ESTRO Anniversary
GEC-ESTRO • EIOF • 11th Biennial
8-12 May, 2011
London, United Kingdom

Cover image: © Sedmak - iStockphoto.com / © Killroy Productions - iStockphoto.com / © Caz - Fotolia.com / © piai - Fotolia.com / © Marina Zlochin - Fotolia.com / © Andresr - iStockphoto.com / © Alex Yeung - Fotolia.com / © Dragomir Uzunov - Fotolia.com

ESTRO Anniversary
GEC-ESTRO • EIOF • 11th BIENNIAL
8-12 May, 2011 • London, United Kingdom

C ONTENT

Saturday, May 7, 2011
Poster discussion
Poster Rapporteur Session: Breast I (Abs. 1-6)
Poster Rapporteur Session: Breast II (Abs. 7-11)
Poster Rapporteur Session: Sarcoma, CNS-Tumors (Abs. 12-19)
Poster Rapporteur Session: Physics, Techniques, Dosimetrics I (Abs. 20-25)
Poster Rapporteur Session: Physics, Techniques, Dosimetrics II (Abs. 26-32)
Poster Rapporteur Session: GI / GU Tumors I (Abs. 33-37)
Poster Rapporteur Session: GI / GU Tumours II (Abs. 38-41)

Monday, May 9, 2011
Teaching lecture
The future of brachytherapy: what are the potential new radionuclides? (Abs. 42)

Symposium
30 years of radiation oncology in Head & Neck cancer - What is the evidence that ‘we’ have created? (Abs. 43-45)
ESTRO-ESSO Joint Symposium: 30 years of radiation oncology in Rectal cancer - What is the evidence-base that‘we’ have created? (Abs. 46-47)

Teaching lecture
Image registration in radiotherapy (Abs. 48)
Advances in reference dosimetry - where do we go next? (Abs. 49)
Impact of 4DRT and RTTs role (Abs. 50-51)

Symposium
Evolution of MRI guided BT in cervix (Abs. 52-54)

Symposium
Dose calculation beyond TG43: impact on clinicians and requirements from vendors (Abs. 55-58)
Head & Neck cancer- What is the evidence that is being created right now? - The best of clinical trials (Abs. 59-62)

ESTRO-ESSO Joint Symposium: Rectal cancer - What is the evidence-base that is being created right now? The best of clinical trials (Abs. 63-65)

Symposium
Functional imaging for tumour and normal tissue characterization (Abs. 66-68)
Novel dosimetry methods (Abs. 69-71)
From conventional to advance practice on miscellaneous treatments (Abs. 72-74)

Proffered paper

Safety in radiation therapy - Joint Symposium with Physics (Abs. 144-146)

Proffered paper
GEC Proffered Papers 3: Cervix Cancer (Abs. 147-153)
GEC Proffered Papers 4: Brachytherapy Physics (Abs. 154-160)

Symposium
ESTRO – JASTRO Joint Symposium: What is the level of evidence needed in Particle Therapy? (Abs. 161-164)

GEC Proffered Papers 1: Breast Cancer (Abs. 75-81)
GEC Proffered Papers 2: Prostate Toxicity (Abs. 82-88)

Proffered paper

Symposium

Clinical Proffered Papers 2: Rectal Cancer (Abs. 165-170)
Physics Proffered Papers 3: Highlights (Abs. 171-175)
Physics Proffered Papers 4: Dose Volume Parameters and Biological Modelling (Abs. 176-182)
RTT Proffered Papers 2: Head and Neck Cancer Treatment (Abs. 183-189)

Head & Neck cancer - Vision for the future: What ‘we’ will ask for in the new grant applications? Biological andimage guided adaptive radiotherapy (Abs. 89-91)
ESTRO-ESSO Joint Symposium: Vision for the future: What ‘we’ will ask for in the new grant applications? Translational research / High technology (Abs. 92-94)

Proffered paper
Physics Proffered Papers 1: Response Prediction: Geometry and Precision (Abs. 95-101)
Physics Proffered Papers 2: Basic Dosimetry (Abs. 102-108)
RTT Proffered Papers 1: Professional Development and Risk Management (Abs. 109-115)

Award lectureAward Lectures (Abs. 116-118)

Symposium
Are there (re)new indications for brachytherapy (Abs. 119-121)
Risks to normal tissue from current and emerging radiotherapy modalities: the results and recommendations of
the ALLEGRO Project (Abs. 122-126)
New frontiers in metastatic cancers - Session developed in collaboration with ASCO and ESMO (Abs. 127-130)

Proffered paper
Clinical Proffered Papers 1: Head and Neck (Abs. 131-137)

Symposium
Intra-fraction challenges - Equipment (Abs. 138-140)
New developments and innovative approaches (Abs. 141-143)

Symposium

Tuesday, May 10, 2011
Teaching lecture
Publications of brachytherapy articles: overview and current trends with focus on “radiotherapy and oncology”(Abs. 190)

Symposium
30 years of radiation oncology in Lung cancer- What is the evidence that ‘we’ have created? - Update on
randomized trials and Meta-analyses (Abs. 191-192)
30 years of radiation oncology in Breast cancer - What is the evidence that ‘we’ have created? - Update on
randomized trials and Meta-analyses (Abs. 193-194)

Teaching lecture
Volumetric imaging: adaptive radiotherapy strategies for clinical implementation (Abs. 195)
A critical overview of arc therapy techniques (Abs. 196)
Image-guided adaptive radiation therapy - more than a verification tool (Abs. 197)

Symposium
The necessity of quality assurance in brachytherapy (Abs. 198-200)
ESTRO-ESTS-ERS Joint symposium: Lung Cancer - What is the evidence that is being created right now? - Thebest of clinical trials - Early stage NSCLC (Abs. 201-205)
Breast cancer - What is the evidence that is being created right now? - The best of clinical trials (Abs. 206-208)

Symposium

Symposium

Intra-fraction challenges - prediction models (Abs. 209-211)

Inter-fraction (between fractions) challenges - organ deformation and motion (Abs. 280-282)

Symposium

Symposium

QA for rotational therapy (Abs. 212-215)

Brachytherapy - imaging and dose adaptation. Joint with GEC-ESTRO (Abs. 283-285)

Symposium

Symposium

IMRT Planning and verification (Abs. 216-218)

Functional imaging and image technology (Abs. 286-288)

Proffered paper

Proffered paper

GEC Proffered Papers 5: Brachytherapy in anal, rectal, bladder and soft tissue sarcomas (Abs. 219-224)
GEC Proffered Papers 6: Prostate (Abs. 225-231)

GEC Proffered papers 7: Head and Neck (Abs. 289-295)
GEC Proffered Papers 8: Gynecological Cancer (Abs. 296-302)

Symposium

Symposium

ESTRO-ESTS-ERS Joint symposium: Lung Cancer - Vision for the future: What ‘we’ will ask for in the new grantapplications? - Translational research / High technology (Abs. 232-234)
Breast cancer - Vision for the future: What ‘we’ will ask for in the new grant applications? - Translational research /High technology (Abs. 235-237)

ESTRO - CARO Joint Symposium: Translating research in imaging into clinical practice (Abs. 303-306)

Proffered paper

Clinical Proffered Papers 4: Breast Cancer (Abs. 307-312)
Physics Proffered Papers 7: IMRT planning and optimisation (Abs. 313-319)
Physics Proffered Papers 8: Functional Imaging (Abs. 320-326)
RTT Proffered Papers 4: Imaging for Treatment Planning and Position Verification (Abs. 327-333)

Physics Proffered papers 5: Strategy and Developments in IGRT (Abs. 238-244)
Physics Proffered Papers 6: IGRT: 4D and Breathing Adapted (Abs. 245-251)
RTT Proffered Papers 3: Treatment Planning and Delivery (Abs. 252-258)

Award lecture

Proffered paper

Wednesday, May 11, 2011

Award Lectures (Abs. 259-263)

Symposium
Treatment of Intermediate-risk prostate cancer patients (Abs. 264-266)
EU Projects: ARTFORCE and ULICE (Abs. 267-269)

Symposium
ESTRO-ASTRO Joint symposium: How high precision technology will change our life (Abs. 270-273)

Proffered paper
Clinical Proffered Papers 3: Lung Cancer (Abs. 274-279)

Symposium
30 years of radiation oncology in Prostate cancer - What is the evidence-based that ‘we’ have created? (Abs.
334-336)

Symposium
30 years of radiation oncology & Normal tissue - What is the evidence that ‘we’ have created? (Abs. 337-338)

Teaching lecture
The tumor micro-environment (Abs. 339)
Physical processes in proton and ion therapy (Abs. 340)
Scope of Practice in the New Core Curriculum for RTs (Abs. 341)
How to convert good material into a good paper in a medical physics or clinical journal (Abs. 342)

Symposium

Presidential symposium

ESTRO-EAU Joint Symposium: Prostate Cancer - What is the evidence-based that is being created right now?
The best of clinical trials (Abs. 343-346)
Normal tissue - What is the evidence-base that is being created right now? The best of needed clinical trials (Abs.
347-350)

ESTRO-ESMO-ESSO-ECCO Presidential symposium: Clinical Oncology: The future of Radiotherapy, Medical
Oncology and Surgical Oncology (Abs. 490-494)

Symposium
Brachytherapy - dosimetry and dose calculation (Abs. 351-353)
Risk assessment and dosimetry in proton and ion therapy (Abs. 354-356)
Clinical audits in radiotherapy - Joint with Physics (Abs. 357-359)
PhD in medical physics, and then......? some in-vivo experiences (Abs. 360-363)

Symposium

Proffered paper
Clinical Proffered Papers 5: Prostate & Gynaecology (Abs. 495-501)

Symposium
Highlights in ESTRO Physics (Abs. 502-504)
Normal tissue dose response modelling beyond the QUANTEC project (Abs. 505-507)

Symposium

ESTRO-EAU Joint symposium: Prostate Cancer - Vision for the future: What ‘we’ will ask for in the new grantapplications? - Translational research / High technology (Abs. 364-366)

Improvement of staff and patient environment (Abs. 508-510)

Symposium

Proffered paper

Normal tissue - Vision for the future: What ‘we’ will ask for in the new grant applications? - Translational research /High technology (Abs. 367-369)

Accessibility of RT resources in Europe and the World (Abs. 511-515)
Clinical Proffered Papers 6: Normal Tissue Effects and Quality of Life (Abs. 516-521)
Physics Proffered Papers 11: In vivo and online dose measurements (Abs. 522-528)
Physics Proffered Papers 12: Image registration and segmentation (Abs. 529-535)
RTT Proffered Papers 5: Patient Care (Abs. 536-542)

Proffered paper
Physics Proffered Papers 8: Highlights - Small and non-reference field Dosimetry (Abs. 370-376)
Physics Proffered Papers 9: Challenges in Treatment Planning (Abs. 377-383)
Physics Proffered Papers 10: Monitoring Treatment Parameters (Abs. 384-390)

PosterYoung scientists ESTRO Poster Session: Trial design and data analysis (Abs. 391-397)
Young scientists ESTRO Poster Session: Treatment planning studies (Abs. 398-404)
Young scientists ESTRO Poster Session: High precision techniques: stereotactic and protons (Abs. 405-411)
Young scientists ESTRO Poster Session: IMRT optimisation (Abs. 412-418)
Young scientists ESTRO Poster Session: Radiation protection and dosimetry (Abs. 419-425)
Young scientists ESTRO Poster Session: IMRT Verification and QA (Abs. 426-432)
Young scientists ESTRO Poster Session: Monte Carlo (Abs. 433-439)
Young scientists ESTRO Poster Session: Functional imaging (Abs. 440-446)
Young scientists ESTRO Poster Session: Radiobiology and dose volume parameters (Abs. 447-453)
Young scientists ESTRO Poster Session: IGRT 4D (Abs. 454-460)
Young scientists ESTRO Poster Session: Rotational IMRT (Abs. 461-467)
Young scientists ESTRO Poster Session: Image analysis (segmentation and registration) (Abs. 468-474)
Young scientists ESTRO Poster Session: IGRT (Abs. 475-481)
Young scientists ESTRO Poster Session: Radiation technologists (Abs. 482-487)

Conference lecture
Honorary Members Award Lectures (Abs. 488-489)

Thursday, May 12, 2011
Symposium
30 years of radiation oncology in Gynecological cancer - What is the evidence that ‘we’ have created? – Updateon randomized trials and Meta-analyses (Abs. 543-545)

Symposium
Testis (Abs. 546-548)

Teaching lecture
The current status of stereotactic body radiotherapy (Abs. 549)
Development of procedures for in vivo dosimetry in radiotherapy (Abs. 550)
Focus on target volume delineation of the upper GI track (Abs. 551-552)

Symposium
ESTRO-ESGO Joint Symposium: Gynecological Cancer - What is the evidence-based that is being created rightnow?- The best of clinical trials (Abs. 553-556)

Interactive session
Ethical issues in managing oncology patients (Abs. 557)

Symposium
Incorporation of molecular and genetic patterns in dose response models (Abs. 558-560)
New beam acceleration for proton and ion therapy (Abs. 561-563)
Guidelines and protocols in the radiotherapy department (Abs. 564-566)
ESTRO-ESGO Joint symposium: Gynecological Cancer - Vision for the future: What ‘we’ will ask for in the new
grant applications? - Translational research / high technology (Abs. 567-570)
ESTRO-EANM Joint Symposium: Imaging (Abs. 571-573)
How to meet the needs for QA in adaptive radiotherapy? (Abs. 574-576)
Mobility of medical physicists in the world (Abs. 577-579)
Improving delivery accuracy by using in-room imaging (Abs. 580-582)

DebateOnline transmission in vivo dosimetry renders pre-treatment QA obsolete (Abs. 583-584)

Posters
ISIORT Meeting

Breast Cancer (Abs. 1-591)
585-591)
GI and Pelvic Tumors (Abs. 592-593)
IORT Technologies, Physics and Biology (Abs. 594-601)
Other topics (Abs. 602-603)
Sarcoma, Head Neck, CNS-Tumors (Abs. 604-606)

GEC-ESTRO Meeting

Brachytherapy: Breast Cancer (Abs. 607-629)
Brachytherapy: Gynaecology (Abs. 630-669)
Brachytherapy: Head Neck (Abs. 670-671)
Brachytherapy: Miscellaneous (Abs. 672-680)
Brachytherapy: Physics (Abs. 681-696)
Brachytherapy: Prostate Cancer (Abs. 697-730)
Brachytherapy: Skin Cancer (Abs. 731-734)

ESTRO International Oncology Forum (EIOF)
Breast cancer (Abs. 735-783)
Gynecological cancer (Abs. 784-807)
Head Neck cancer (Abs. 808-881)
Lung cancer (Abs. 882-902)
Lymphoma (Abs. 903-909)
Normal tissue (Abs. 910-920)
Others (Abs. 921-994)
Palliation (Abs. 995-1005)
Prostate cancer (Abs. 1006-1047)
Rectal cancer (Abs. 1048-1073)

Testis (Abs. 1074-1075)

11th Biennial Physics and RTT

Brachytherapy: Image guidance (Abs. 1076-1079)
Brachytherapy: planning and optimization (Abs. 402-1086)
Brachytherapy: Verification and dosimetry (Abs. 1087-1091)
Disease specific issues (Abs. 1092)
Dose measurement: applied (1D/2D) (Abs. 1093-1096)
Dose measurement: applied (3D/4D) (Abs. 1097-1100)
Dose measurement: basic (Abs. 1101-1111)
Dose measurement: Novel detectors (Abs. 424-1124)
Dose measurement: small and composite fields and flattening free (Abs. 423-1136)
Dose Volume parameters and outcome studies (Abs. 396-1149)
Education and training (Abs. 1150-1156)
Functional imaging for RT and treatment planning (Abs. 440-1172)
IGRT: 4D imaging (Abs. 455-1182)
IGRT: Adaptive treatment schemes and correction strategies (Abs. 1183-1207)
IGRT: Breathing adapted Radiotherapy (Abs. 454-1218)
IGRT: Concomittant dose (Abs. 1219-1221)
IGRT: QA of imaging devices and geometric accuracy (Abs. 479-1228)
IGRT: Treatment delivery and patient positioning (Abs. 458-1263)
IGRT: Volume definition, treatment margins and geometric uncertainties (Abs. 474-1280)
Image registration, segmentation algorithms and delineation (Abs. 468-1298)
IMRT: Clinical implementation (Abs. 1299-1308)
IMRT: Rotational therapies (Abs. 461-1335)
IMRT: Treatment planning and optimization (Abs. 412-1358)
IMRT: Treatment verification and QA (Abs. 427-1383)
MC developments (Abs. 1384-1387)
MC for Brachy (Abs. 1388-1391)
MC for dosimetry and QA (Abs. 433-1398)
MC for TPS (Abs. 436-1407)
Patient care (Abs. 1408-1409)
Patient immobilization and support aids (Abs. 483-1417)
Proton and ion therapy: Clinical (Abs. 410-1418)
Proton and ion therapy: Physics (Abs. 409-1428)
QA for IMRT and rotational therapy techniques (Abs. 426-1449)
QA: Audit, risk management and legal issues (Abs. 484-1455)
QA: In vivo dosimetry (Abs. 432-1464)
QA: of equipment (Abs. 1465-1488)
QA: of software (Abs. 1489-1493)
Radiation Protection (Abs. 419-1501)
Radiation technologists (Abs. 482-1509)
Radiobiological modelling (Abs. 451-1518)
SRS-SBRT (Abs. 405-1539)
Treatment planning and dose calculation (Abs. 398-1572)
Trials: Techniques, dosimetry and QA (Abs. 391-1584)
Undergraduate, postgraduate and continuous education (Abs. 1585-1589)

A BSTRACTS C ONFERENCES ATURDAY, M AY 7, 2011

Saturday, May 7, 2011
Poster discussion
Poster Rapporteur Session: Breast I
1 poster
FAT NECROSIS AND PARENCHYMAL SCARRING AFTER BREASTCONSERVING SURGERY AND RADIOTHERAPY WITH AN INTRAOPERATIVE ELECTRON OR FRACTIONATED, PERCUTANEOUS
BOOST – A MATCHED-PAIR COMPARISON
M. D. Piroth1 , K. Fischedick1 , B. Wein2 , U. Heindrichs3 , D. Piroth3 , R.
Holy1 , M. Pinkawa1 , M. Eble1
1
RWTH A ACHEN U NIVERSITY H OSPITAL, Radiation Oncology, Aachen,
Germany
2
R ADIOLOGISCHE G EMEINSCHAFTSPRAXIS AM K APUZINERKARREE,
Aachen, Germany
3
RWTH A ACHEN U NIVERSITY H OSPITAL, Gynecology and Obstetrics,
Aachen, Germany
Purpose: Radiotherapy after breast conserving surgery can cause fat necrosis, fibrosis, skin thickening or parenchymal scarring complicating the interpretation of follow-up mammograms. The aim of this retrospective analysis
was to evaluate mammographic changes in breast tissue within the first 3
years after breast conserving surgery and whole breast irradiation with anadditional IOERT- versus percutaneous boost.
Materials: A total of 53 breast cancer patients (stage I/II) treated between
2006 and 2008 were included. All patients were treated with breast conserving surgery followed by a fractionated whole breast radiotherapy with a
total dose of 50.4 Gy. Twenty patients had a 10 Gy intraoperative electron
boost (IOB), performed with the mobile Linac NOVAC 7. These patientswere matched-pair compared with 33 patients treated with a fractionated,
percutaneous electron boost (FPB) with median 10 Gy according to age, tumor stage, tumor localization or adjuvant systemic treatment. The follow-up
mammograms, performed every 6-12 months, were focused on fat necroses,
parenchymal scarring and skin thickening. Mammographic changes were diagnosed by a radiologist in a blinded setting. The fisher exact test was used
to detect significant differences.
Results: Fat necroses occurred significantly more frequent in IOB-patientscompared to FPB-patients (50 vs. 18.2 %, p=0.02) (fig 1). The fat necroses
were mammographically detected median 17 vs. 23 months post surgery for
the IOB vs FPB patients. The median size of fat necroses was 24 (14-30) mm
for the IOB-group and 14 (4-53) mm for the FPB-group. The parenchymal
scarring grade 3-4 was significantly more frequent seen in the IORT-boost
patient mammograms (63.2 vs. 21.9 %, p=0.006) (fig 1). The skin-thickening
differed not significantly in the two cohorts (p=0.1) (fig 1). In seven patients(IOB: 5, FPB: 2) the mammographically diagnosis was verified histologicallybecause of diagnostic uncertainties

Conclusions: According to the literature an IORT-boost lead to significantly
more fat necroses and parenchymal scarrings in our analysis. The knowledgeof this phenomenon is clinically relevant because it can mimick in-breast recurrences. The radiotherapy technique must be included in the diagnostic
process of differentiation between posttherapeutic changes and recurrence.
In uncertain cases the MR-mammogramm seems to be helpful but if the clarifying is not completely possible, the biopsy is mandatory.

P OSTER DISCUSSION

S5

2 poster
10-YEARS RESULTS OF INTRAOPERATIVE ELECTRON RADIOTHERAPY (IOERT) IN BOOST MODALITY IN BREAST CANCERPATIENTS TREATED WITH BREAST CONSERVING SURGERY.
G. Fastner1 , R. Reitsamer2 , M. Kopp1 , C. Menzel2 , S. Glück2 , F. Merz1 , P.
Kopp1 , H. Deutschmann1 , F. Sedlmayer1
1
P RIVATE U NIVERSITY C LINIC S ALZBURG, Radiation Oncology, Salzburg,
Austria2
P RIVATE U NIVERSITY C LINIC S ALZBURG, Senology Department, Salzburg,
Austria
Purpose: The aim of this nonrandomized study was to compare ipsilateralbreast tumor recurrence rates in patients with invasive breast cancer, who
had been treated with breast conserving surgery and whole breast irradiationand conventional boost or intraoperative electron radiotherapy boost (IOERT).
Materials: 378 patients were included in the study, 188 patients in group
1 (conventional boost) and 190 patients in group 2 (IOERT boost). Patientswere comparable with regard to age, menopausal status, tumor size, histological type, grading and axillary lymph node status. Included were patients withinvasive breast cancer pT1 and pT2, N0, N1, N2, M0 and breast conserving
surgery with clear margins > 3mm. Excluded were patients with DCIS only,
patients with invasive breast cancers larger than pT2, patients after primarysystemic therapy and patients with multicentric disease. All patients (group 1
and group 2) received postoperative whole breast irradiation of 51 - 56,1 Gy.
Group 1 received postoperative electron boost irradiation of 12 Gy after wholebreast irradiation and group 2 received one intraoperative electron boost of 9
Gy in a single fraction during surgery before whole breast irradiation.
Results: The 10 - years actuarial rates of ipsilateral breast tumor recurrence (IBTR), true local recurrence (TLR), distant recurrence (DR) and disease free survival (DFS) were 7.1% (95%CI, 3.2-11.0%), 4.8% (95%CI, 1.58.0%), 14.2% (95%CI, 9.1-19,4%) and 82.4% respectively in group 1 and2.7% (95%CI, 0.0-5.9%, P=0,062), 0.7% (95%CI, 0.0-2.0%, P=0.016), 13.6%(95%CI, 5.0-22,2%, P=0.90) and 84.0% (P=0.76) respectively in group 2.
Conclusions: Patients treated with IOERT boost and whole breast irradiationachieve excellent local control rates at 10 years and exhibit statistically significant decreased true local recurrence rates compared to patients treated withwhole breast irradiation and conventional electron boost.
3 poster
IPSILATERAL BREAST TUMOR RECURRENCE RATES IN BREASTCANCER PATIENTS TREATED WITH PREOPERATIVE CHEMOTHERAPY, BREAST CONSERVING SURGERY AND INTRAOPERATIVERADIOTHERAPY WITH ELECTRONS
G. Fastner1 , R. Reitsamer2 , C. Menzel2 , S. Glück1 , M. Kopp1 , F.
Peintinger3 , F. Sedlmayer1
1
P RIVATE U NIVERSITY C LINIC S ALZBURG, Radiation Oncology, Salzburg,
Austria2
P RIVATE U NIVERSITY C LINIC S ALZBURG, Senology Department, Salzburg,
Austria
3
G ENERAL H OSPITAL L EOBEN, Department of Gynaecology, Leoben,
Austria
Purpose: Ipsilateral breast tumor recurrence (IBTR) rates are reported to be
increased in patients treated with breast conserving surgery after preoperative chemotherapy. Aim of this study was to evaluate the IBTR rate in patients
who were treated with preoperative chemotherapy followed by breast conserving surgery and intraoperative radiotherapy with electrons (IOERT).
Materials: 84 patients with clinical stage II or III breast cancer were includedin the study. Patients received 3 to 6 cycles of anthracyclin/taxane containing preoperative chemotherapy. All patients had breast conserving surgery
with sentinel node biopsy and axillary lymph node dissection and received
intraoperative radiotherapy with 9 Gy to the 90% reference isodose as an anticipated boost radiation. Whole breast radiotherapy (WBRT) was preformed
after surgery for all patients.
Results: Pathologic complete response was achieved in 18/84 (21%) patients. Mean resection volume was 250 ml. After a median follow-up of 30.5
months (range 6-77 months) no IBTR could be observed. One patient developed a locoregional recurrence an the axilla and nine patients developed
distant disease, five of those died of disease. Three patients developed contralateral breast cancer. 71 patients are alive wthout evidence of disease.
Conclusions: Breast conserving surgery with IOERT in boost modality after preoperative chemotherapy is a reliable tool for prevention of IBTR. The
period between IOERT and WBRT is short as no adjuvant chemotherapy isnecessary. Cosmetic outcome is excellent.

S6

P OSTER DISCUSSIONS ATURDAY, M AY 7, 2011

4 poster
MRI AND FROZEN SECTION IN DECISION MAKING OF IOERT IN
BOOST MODALITY OF THE BREAST
C. Schumacher1 , N. Hindrichs1 , S. Eidt2 , A. Ricke3 , J. Jennissen3 , M.
Jergas4
1
S T. E LISABETH -K RANKENHAUS, Breast Cancer Center, Cologne, Germany
2
S T. E LISABETH -K RANKENHAUS, Pathology, Cologne, Germany
3
CDT-S TRAHLENINSTITUT, Radiation Oncology, Cologne, Germany
4
S T. E LISABETH -K RANKENHAUS, Radiology, Cologne, Germany
Purpose: IORT (intraoperative radiation therapy) in boost modality combinedwith postoperative WBRT (whole breast radiation therapy) has become astandard procedure in breast cancer therapy of unicentric disease resulting
in low recurrence rates. In order to identify the patients egliable for this procedure and to obtain low re-excision rates after IORT we investigated the roleof additional preoperative MRI and intraoperative frozen sections in decision
making of IORT in boost modality.
Materials: From february 2009 to february 2010 every patient with histologically proven invasive carcinoma, T1 and T2, N0 and N+ and supposed
unicentricity by palpation, mammography and ultrasound was enrolled in the
study. In every patient we performed MRI scanning of the breast preoperatively. During surgery in every patient frozen section of the margins and of all
additional MRI marked lesions not biopsied before was performed. IOERT inboost modality was applied after verified unicentric disease and free margins
by frozen section with the mobile electron beam accelerator Mobetron with adose of 9 Gy.
Results: A total of 209 patients were enrolled in the study. The medianage of our patients was 60,6 years, the median tumor size was 14,8 mm.
In 78% of the patients a nodal involvement was missing, 58,9% of the tumors were G2, 87,6% hormonreceptor positive and 90,4% HER 2 negative.
The most frequent histologic subtype was the ductal carcinoma. In 169 patients the IOERT-boost was performed, in 40 patients the decision against IOERT was made according to the frozen section result during surgery.In 17,6%
MRI showing multicentricity was the reason for decision making against IORT.
In 37,6% we decided against the boost because of extensive intraductal lesions or microinvasive components seen in frozen section. In 36% we hadn‘tenough tissue to mobilize for performing the boost after the resection of thetumor. In 10% we found other reasons especially problems concerning general anaesthesia not permitting us the time to perform the boost. By using
MRI in 5,7% of the patients multicentricity was detected precluding BCT and
IORT, in 12,0% of the patients the resection volume was modified by the results of MRI and frozen sections. Frozen section of the margins played an
important role by detection of DCIS- and microinvasive components: in 7,2%of the patients extensive multifocality or multicentricity was detected precluding BCT and IORT, in 14,8% of the patients with IORT resurgery after IORT
was prevented.
Conclusions: MRI and mainly frozen section are important tools to lower
the rate of resurgery after IORT: 22,5% (47/209) of all study patients had abenefit.
5 poster
EXCLUSIVE I.O.R.T. FOR EARLY STAGE BREASTRESULTS AFTER FIRST 50 CASES
M. Dessena1
1
EXPERIMENTAL SURGERY , oncologic surgery, cagliari, Italy

CANCER:

Purpose: To evaluate feasibility, tolerability and cosmetic outcome of intraoperative radiation therapy (IORT) as an exclusive post surgery treatment ofearly stage breast cancer.
Materials: From October 2008 to October 2010 50 patients underwent wide
breast cancer excision or quadrantectomy followed by IORT on tumor bed
with accelerated electrons at the dose of 21Gy. The characteristics of thepatients were the followings: ductal breast cancer or invasive lobular pT1,
pT2 ≤ 2.5 cm, pN0, G1-2, negative margins, age over 35, M0.
Results: The average age was 54.9 (range 38 79) with an average follow
up of 15 months (range 2 24). The pathologic stage of the lesions resulted
pT1 in 46 cases (92,0%), in particular: one case pT1a (2,0%), 38 cases
pT1b (76,0%) and 7 cases pT1c (14,0%); 4 case (8,0%) was pT2 with adiameter of 2.5 cm. .The Grading was G2 in 35 cases (70,0%) and G1 in
15 cases (30,0%). The toxicity, evaluated according to the EORTC-RTOG
criteria, was G0 (40.0%) in 20 cases, G1 (52,0 %) in 26 cases, G2 in 3 case
(6,0%); only one was G3 (2.0%) . The time needed for a complete healingof the wound was less than 10 days in 94,0% of the cases, with 3 case oflimphocele (6,0%); there were no infections of the surgical wound nor any
mastitis, neither in the treated quadrant nor in the other ones.We observed
a light fibrosis in 8 cases (16,0%), moderate in 4 cases (8,0%) but never
severe. Cosmetics, evaluated according to Danoff and co., in four levels,
was excellent in 9 cases (18,0%), good in 35 cases (70.0%), sufficient in 6
cases(12,0%), never insufficient.As regards local control, there was no local
relapse. The global survival was 100%.
Conclusions: The IORT in early breast cancer, at the doses used in thisstudy, proved itself as a secure technique, repeatable, with limited complica-

tions.The advantages of its use are the possibility of a direct control, by thesurgeon and the radiotherapist, of the structures to treat and those to protect;the absence of time needed for cellular repopulation between surgery and radiotherapy, a good cosmetic outcome and logistic advantages.It is necessary
to have a long term follow up to evaluate the efficacy in terms of long term
cosmetic local control.
6 poster
FEASIBILITY OF INTRAOPERATIVE RADIATION THERAPY (IORT)IN WOMEN WITH EARLY BREAST CANCER
L. Belgioia1 , M. Guenzi2 , A. D’Alonzo2 , G. Timon1 , F. Ricchetti2 , S.
Agostinelli2 , R. Corvò2
1
U NIVERSITY OF G ENOA, Radiation Oncology, Genoa, Italy
2
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Radiation Oncology,
Genova, Italy
Purpose: The rationale of partial breast irradiation (PBI) is based on thefinding that most local relapses after breast conserving surgery occur at tumor
bed. Since techniques of PBI include intraoperative radiation therapy (IORT),
our purpose was to evaluate the feasibility of IORT at two different doses inpatients with early breast cancer. This investigation was approved in 2009 by
IST Ethical Committee.
Materials: Eligibility criteria for IORT included pts aged 45 to 85 years withunifocal and non lobular invasive carcinoma, a maximum tumor diameter of
2.5 cm, negative margin, intraductal component <25% and no previous history of cancer. Before performing IORT, primary tumor was evaluated during
surgery by a pathologist to confirm the eligibility criteria and to guarantee
safe surgical margins. Prescription dose depends on tumor size; if < 1 cm
total planned dose was 18 Gy, if > 1cm (up to 2.5 cm) the pts received thestandard dose of 21 Gy. Using α/β ratio for breast tumor of 4 Gy, 21 Gy in 1
fraction would be biologically equivalent to 70 Gy in 35 fractions, such a dosebeing suitable for high risk pts (pT1c and pT2): 18 Gy (equivalent to 60 Gy in
30 fractions) seems to be appropriate for low risk pts (pT1a-pT1b). Full-dose
intraoperative radiotherapy with electrons was delivered using a LIAC (Sordina, Padova, Italy), a mobile linear accelerator delivering an electron beamwith energies ranging from 4 to 10 Mev. After tumor removal, breast gland
was separated from skin and pectoralis major muscle and was sutured over a
dedicated shielding disk; this procedure allows excellent sparing of skin, subcutaneous tissue and chest wall. From April 2010, in-vivo dosimetry was performed using a metaloxide semiconductor field-effect transistor (MOSFET)
detector placed on the outer face of the shielding disk.
Results: From September 2009 to November 2010 136 pts met the protocol pre-surgical eligibility criteria approved at our Institute. Eligibility criteria
were confirmed at extemporary pathological examination in 97 pts (71%) who
therefore received IORT only; 58 (60%) received 21 Gy and the other 39(40%) received 18 Gy. 39 (29%) pts were not considered eligible to exclusive
IORT; 20 were treated with IORT boost (10 Gy) followed by whole breast radiation, whereas 19 pts did not receive IORT at all. Definitive pathology report
supported intraoperative diagnosis of ductal invasive carcinoma in 88 cases;in the other 9 cases it was mucinosus carcinoma (2), apocrine carcinoma (1),tubular carcinoma (1), cribriform carcinoma (3) and lobular carcinoma (2).
The time consumption due to IORT procedure is modest even when in-vivo
dosimetry is performed, being no more than 30 minutes. Cosmetic outcomeswith IORT are satisfying (good or excellent in 77% pts).
Conclusions: IORT is feasible in selected pts with low risk early breast cancer, and the procedure-related time consumption is not an issue in our experience.

Poster Rapporteur Session: Breast II
7 poster
IORT AS ANTICIPATED BOOST IN EARLY STAGE BREAST CANCER:TEN YEARS FOLLOW UP AT S. FILIPPO NERI HOSPITAL IN ROME
A. Ciabattoni1 , M. A. Mirri1 , V. Ciccone1 , T. Palloni1 , F. Vidiri1 , S. Drago2 ,A. Petrucci3 , F. P. Mangiacotti3 , R. Consorti3 , G. Grassi2
1
A ZIENDA C OMPLESSO O SPEDALIERO S AN F ILIPPO N ERI R OMA, UOC
Radioterapia, roma, Italy
2
A ZIENDA C OMPLESSO O SPEDALIERO S AN F ILIPPO N ERI R OMA, UO
Chirurgia, roma, Italy
3
A ZIENDA C OMPLESSO O SPEDALIERO S AN F ILIPPO N ERI R OMA, Fisica
Sanitaria, roma, Italy
Purpose: The effect of a radiation boost tailored to the risk area in the treatment of early stage breast cancer has been investigated in many studies.
The intraoperative radiotherapy (IORT) boost allows to reach higher doses inbreast tissue, avoiding the skin and many experiences reported an incidenceof local recurrence near zero. The aim of this study is to present the results often years follow up on local control, esthetic evaluation and toxicity of I◦ andII◦ stage breast cancer treated with 10 Gy IORT as anticipated boost

S ATURDAY, M AY 7, 2011Materials: From April 1999 to March 2010 IORT given as boost in early breast
cancer patients has been carried on at San Filippo Neri Hospital in Rome. A
total of 278 patients up to 75 years (range 29-75), I◦ and II◦ stage breast
cancer and ECOG performance status < 2, were treated with an anticipatedboost dose of 10 Gy to PTV (tumour volume with a radial margin of 1 to 2
centimetres). The boost was delivered with a movable Linac NOVAC7. All
the patients received additional 45-50 Gy of external radiotherapy in 18-25
fractions to the whole breast. One hundred and twenty six patients were
included in a randomized trial carried on from April 1999 to December 2004
of IORT versus external beam boost The valuation of acute and late toxicity
was performed using WHO scale and the aesthetic result was assessed.
Results:
The median follow-up was 82,7 months (range 2-138
months).Seventy eight patients (28%) were women younger than 45 years.
Two local recurrence were observed: one (true local recurrence) presented
in a 62 years old patient with a ductal infiltrating carcinoma staged as
pT1bN0Mx, G2, after 100 months follow up and the other (marginal recurrence) in a 56 yearss old patient with a ductal infiltrating carcinoma staged
as pT1cN0Mx, G3, at 112 months follow up. No local failures were observed in the group of young women. As acute toxicity 22 patients developed
post-surgical seromas and 7 wound healing problems occurred (6,8%). No
late complications associated with IORT were observed, but three cases ofliponecrosis in the treatment area. In 7 patients, a secondary mastectomy
was performed for tumour multicentricity or excessive intraductal component.
Cosmetic result was very good (objective valuation 92,3% good or excellent,
subjective valuation 88,7%) and comparable to patients treated with externalboost (87,4% good or excellent). The overall DFS was 88,7%, 23 patientsdeveloped distant metastasis and 12 died (nine of them for disease). Six
patients were lost at the follow up
Conclusions: Our data suggest that IORT as anticipated boost after breastconserving surgery is a reliable alternative to conventional postoperative fractionated boost, particularly in younger women, for whom published studies
indicate higher risk of local recurrence. The incidence of recurrence with the
IORT boost, for any age, including young women, is quite low.Further research is required to clarify several issues such as identification of the mostappropriate subgroups of patients for IORT as boost or complete replacementof postoperative radiotherapy.
8 poster
FOUR YEAR RESULTS OF ELECTRON INTRAOPERATIVE BOOSTAND HYPOFRACTIONATED EXTERNAL BEAM RADIOTHERAPY
AFTER BREAST-CONSERVING SURGERY IN PREMENOPAUSAL
WOMEN
G. B. Ivaldi12 , M. C. Leonardi3 , A. Morra2 , R. Lazzari3 , A. Ferrari3 , C.
Fodor3 , B. A. Jereczek-Fossa3 , R. Orecchia3 , U. Veronesi3
1
F ONDAZIONE S ALVATORE M AUGERI, Department of Radiation Oncology I,
Pavia, Italy
2
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Radiation Oncology,
Milan, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Milan, Italy
Purpose: To report preliminary clinical results of a pilot study of electron
intraoperative boost followed by hypofractionated external beam radiotherapy(HEBRT) of the whole breast .
Materials: Between June 2004 and December 2006, 182 premenopausal
women with a diagnosis of early-stage breast cancer were treated withbreast-conserving surgery and sentinel node biopsy +- axillary dissection.
During surgery, an electron intraoperative boost of 12 Gy was administered
to the tumour bed. Median age was 41 years (24-48). Adjuvant local treatment was completed within 4 weeks by HEBRT consisting of 13 daily fractionsof 2.85 Gy to the whole breast to a total dose of 37.05 Gy. Pathologic stages
were as follow: stage I 84(46%), stage IIA 65 (36%) , stage IIB 17 (9%), stage
IIIA 11 (6%), stage IIIC 3 (2%).13 patients (7.1%) were classified as "triple
negative"( estrogens and progesterone receptor negative and Cerb-B2 notexpressed) . Adjuvant systemic treatment consisted of chemotherapy for 21
patients (11.5%), chemo and endocrine therapy for 64 patients (35.2%), endocrine treatment only for 94 (51.6%) while one patient (1%) did not receive
any systemic treatment. In all cases, adjuvant chemotherapy was started
after the completion of HEBRT. After the end of the treatment all patients
underwent follow-up visits every 6 months with the breast surgeon
Results: At a median follow-up of 51.6 months (range 27-74), 175 patients(96%) are alive and 158 (87%) are free from any recurrence. Two patients(1%) had nodal regional recurrence, 14 patients (8%) had distant metastasis(one died after diagnosis of liver metastasis). Two patients (1%) developed
contralateral breast cancer. Four patients (2%) had a second cancer: (tworectal, one thyroid cancer and one died of a metastatic melanoma). Overall
19 recurrences (10%) were observed, none of them in the ipsilateral breast
Conclusions: The intraoperative radiotherapy boost followed by HEBRT allows delivering a very high dose to the tumour bed plus a adequate dose to
the whole breast in a short time. Preliminary results in terms of local control
are promising. Longer follow-up with a larger patient population will allow a
comparison with historic series in order to confirm the results in terms of local
control and assess the actual efficacy in terms of disease specific and overall
survival of this innovative treatment schedule

P OSTER DISCUSSION

S7

9 poster
INTRAOPERATIVE RADIOTHERAPY (IORT) AS A BOOST DURINGCONSERVING SURGERY IN WOMEN WITH EARLY BREASTCANCER.
Z. Warenczak- Florczak1 , K. Bratos1 , H. Wlodarczyk1 , A. Roszak1 , D.
Murawa2 , A. Karczewska - Dzionk3 , P. Milecki3
1
G REAT P OLAND C ANCER C ENTRE, Department of Gynecological Radiotherapy and Oncology, Poznan, Poland
2
G REAT P OLAND C ANCER C ENTRE, Department of Oncological Surgery,
Poznan, Poland
3
G REAT P OLAND C ANCER C ENTRE, Department of Radiation Oncology I,
Poznan, Poland
Purpose: The standard of care for adjuvant therapy in early breast cancer
include whole breast irradiation. The latest Early Breast Cancer Trialists Collaborative Group systemic review confirmed 75% reduction of local recurrence risk after radiotherapy. A dose-response relationship has also been
demonstrated in "EORTC 22881-10882 boost versus no boost trial" where
significantly fewer local failure(p<0,0001). Intraopertive radiotherapy is one of
the boost method base on irradiating the surgical field immediately after tumor is remove. Whereas often a geographic miss in covering the boost target
occurs with external beam boost, the purpose of IORT is to cover the tumor
bed safely. The aim of the study was to analyze the therapy and cosmetic effects, acute and late toxicity and analysis of the quality of live questionnaires
made by the patients.
Materials: Sixty patients with breast cancer in stage Tis-2N0-1A treated withIORT after conserving surgery were randomized. Definitive pathology results
showed ductal-invasive histology in 49 patients (81,7%). The intraoperatively
delivered dose was 10 Gy prescribe to the applicator surface, using 4-12
MV electrons. We use aluminum-lead shielding disc to protect the thoracic
wall, heart and lung during radiotherapy. In 26 patients (43,3%) we also use
0,5-1cm bolus. Median of the dose dept was 1,97cm. In all cases IORT was
followed by EBRT with total dose of 50Gy in 2 Gy fractions. During 12 months
observation in 1, 6 and 12 month every patient was physical examinated withphotos of the breast and analysis of acute and late toxicity. Every patient
made also the quality of live questionnaires ( QLQ-C30 and QLQ-BR23) during observation. Six months after EBRT mammography with ultrasounds ofthe breast was made in all patients.
Results: No local recurrence occurred during 12 months observation. The
IORT combination with EBRT was well tolerated, with no Grade 3 and 4 skinacute and late toxicities. Acute reactions in Grade 1 and 2 of the skin wereobserved in 23,3% of patients. The cosmetic outcome in physical examination
was good to excellent in 78,3% of patients after 12 months. In quality of live
questionnaires after 1, 6 and 12 months of observation 83,3% of patientsevaluated the effect of the therapy as good and very good. Pain in the breastand more sensitivity of the skin estimated in 35% of patient after 1, 6 and 12
months. Edema of the breast was observed in 14% of patients after 1 monthand in 16% after 6 and 12 months. Changes in the skin were assessed in 36%
of patients after 1 month and in 22% after 6 and 12 months of observation.
Conclusions: Intraoperative radiotherapy is a comfortable, effective methodof delivering a single high-dose to the tumor-bed as a boost. The externalbeam course afterwards is shortened by 1 week. After tumor resection thetumor bed can be ideally adapted to the applicator surface and then treatedby electron. A miss of the boost target volume can be avoided through IORT,
as it is often in EBRT.
10 poster
EXPERIMENTAL STUDY OF SUB-LETHAL DAMAGE (SLD) AND DNA
DOUBLE STRAND BREAK (DSB) REPAIR IN RELATION TO IORT
Q. Liu1 , F. Schneider1 , F. Wenz1 , C. Herskind1
1
U NIVERSITY M EDICAL C ENTER M ANNHEIM, Radiation Oncology,
Mannheim, Germany
Purpose: Intraoperative Radiotherapy (IORT) with isotropic 50 kV x rays involves protracted irradiation with typical delivery times of 30-50 minutes. Thus
continuous induction and repair of sub-lethal damage (SLD) during treatment
may affect the relative biologic effectiveness (RBE) and clinical outcome. The
purpose of the present work was to determine the half-time T1/2 of SLD repair
and to study the relationship between SLD and DSB repair in vitro.
Materials: V79 hamster cells, the human breast cancer cell line MCF7, andearly-passage, normal human skin fibroblast, GS4, were used. Split-dose
irradiation with two acute doses of 6 MV x rays (6 Gy/min) was used to determine recovery of cell survival as function of the time interval. The surviving fraction (SF) was determined by the colony formation assay and survival curves were fitted by the linear-quadratic formalism. T1/2 was determined from the Lea-Catcheside time factor for continuous induction and repair of SLD. Induction and decay of DNA repair foci for DSB was monitored
by immunocytochemistry with γ H2AX antibody. 50 kV x rays from a surface
therapy machine (Siemens Dermopan 2 with 1 mm Al filter, dose rate 0.45
Gy/min) and the miniaturized x rays machine (Intrabeam®PRS400, Carl Zeiss
Surgical GmbH, Oberkochen, Germany; 4 cm spherical applicator) were used
to validate results at low photon energy.

S8

P OSTER DISCUSSION

Results: SLD repair was observed for V79 and MCF7 but not for normal
fibroblasts (time intervals 45 min-6h). SLD repair after irradiation with 50 kV
x rays from Dermopan, was validated using V79 cells. The kinetics of SLD
repair during time intervals relevant for IORT was determined for two acutedoses of 6 Gy (V79) or 4 Gy (MCF7) with time intervals of 5-40 min. Initial
T1/2 was 15 min for V79 with a slowing down of the repair rate after 10-15
min. For MCF7, T1/2 was constant at 39 min over the split-dose range tested.
The kinetics of induction and decay of γ H2AX foci after acute irradiation was
similar in all three cell types. The maximum number of foci in V79 produced bya fixed dose of 4.7 Gy of 50 kV x rays from Intrabeam was found to decrease
with decreasing dose rates.
Conclusions: SLD repair was observed in two of three cell lines with halftimes relevant for the time required to deliver IORT with 50 kV x rays. Thus theeffect of continuous induction and repair of SLD during protracted irradiation
should be included when modelling RBE and clinical outcome of IORT with
low-energy x rays. Although normal skin fibroblasts showed no split-dose
recovery (interpreted as SLD repair), all three cell types were proficient in
DNA repair as detected by γ H2AX foci suggesting that SLD is not identical tolesions detected by γ H2AX. Since cellular radiosensitivity of fibroblasts was
not indicative for clinical risk of late fibrosis in previous studies, experimental
studies of dose rate effects on normal-tissue reaction may require in vivo
models.
11 oralIORT WITH ELECTRONIC BOOST IN THE TUMORBED PRIOR TO
POSTOPERATIVE WBRT AS STANDARD PROCEDURE UNICENTRIC BREAST CANCER
A. Ricke1 , C. Schumacher2 , N. Hindrichs2 , S. Eidt2 , J. Jennissen1
1
CDT-S TRAHLENINSTITUT, Cologne, Germany
2
S T. E LISABETH -K RANKENHAUS, Cologne, Germany
Purpose: We implemented an intraoperative electron boost to the tumor bed
prior to postoperative WBRT as standard procedure during breast conserving
therapy of unicentric tumors.
Materials: Between February 2009 and September 2010 we identified 363
women with supposed unicentric disease in stages T1 /T2, invasive histology,
N0-2, M0, where breast conserving surgery was likely and IORT was planned
as anticipated boost strategy during OP. The final decision to perform IORT
was based on intraoperative histological findings and the ability to mobilize
sufficient breast tissue. 288 patients were treated on a mobile electron accelerator ( Mobetron, Sunnyvale, CA, USA) with a dose of 9 Gy.(10 Gy in the
100% maximum)Cone diameters were 50/55/60 mm in 200 patients; in 56
cases, tube sizes >65 and in 50 cases, sizes <50 mm were used. Irradiatedtissue 228 Pat. with thickness amounted 16-30 mm in 228 pts.; in 45 pts. >30mm and in 13 Pat. <15 mm.
Results: 75 (20,66%) patients were unsuited for IORT for different reasons:inability to mobilize sufficient breast tissue (37), R1 resection (7), multicentric disease (15) and others like DCIS-only, bifokal disease and tumor location close to the nipple (16). 288 Patients (79,34%). Of these, 24 Patients(8.33%) were referred to a re-excision to reach RO-status, 5 patients (1.74%)
underwent secondary mastectomy and another 5 underwent separate axillary dissection . 236 patients had stage pT1-tumors ( 16-pT1a / 70 pT1b /150 pT1c), 51 patients pT2 and one patient stage pT3. 46 patients showed
up with G1-, 174 with G2-, and 68 with G3-Grading. 230 Pat. were classified
node- negative ( 3-pNOi+ / 227- pN0), 45 with pN1- ( 34 pN1 / 11 pNmic), 9with pN2- and 4 with pN3-disease.111 pts. underwent adjuvant chemotherapy (CTX) ,14 pts declined CTX, 7 pts are still in CTX. For patients without
CTX (156), WBRT (50.4) started 6 weeks after surgery ( median 47,76 days,
range 21-83). 4 Patients refused WBRT, received postoperative radiotherapy in another center. In patients treated with adjuvant CTX , the mediandelay between IORT and WBRT amounted 168 days 87-233 ).At a medianfollow-up of 12 months, so far no patient developed in-breast or systemic recurrence.Acute toxicity was assessed 6 weeks after IORT and 2 months after
WBRT ( CTC-Criteria), long term morbidity one year after WBRT according
to Lent Soma and Taylor-score after two years, respectively.Acute reactions:
1. 6 weeks after IORT : 190 evaluated patients: wound infection 12 (
6,23%), seroma 23 (12.11%), hematoma 23 (12.11%), pain 5 (5.79%)
2. 4 weeks post WBRT: 157 evaluated pat. with CTC-score 0 in 127
Pat.(80.89%) CTC I in 27 Pat.(17.2%), 3 Pat.(1.91%) CTC II and 0
Pat. CTC III or IV.
3. Late toxicity: Lent-soma-score : 42 evaluated patients.
4. Edema: score 1 : 12 Pat.; score 2 : 1Pat. and 29 Pat. without.
5. Fibrosis: score 1 :13 Pat. ; score 2 : 4 Pat. and 25 Pat without .
6. Pain: score 1 :13 Pat.; score 2 : 2 Pat. and without 28 Pat.
7. Telangiectasia: score 1: 1Pat. ; score 2: 1 Pat. and without 40 Pat.
8. Atrophy: score 1 3 Pat., without 39 Pat.

S ATURDAY, M AY 7, 2011
Conclusions: Intraoperative histological findings and the inability of mobilizing tissue are the most important factors for excluding patients from IORT.
In short-term follow-up, IORT as boost followed by WBRT yields outstanding
tumor control rates. Time delay between IORT and WBRT did not influence
outcome . No grade >2 acute and late reactions have been observed.

Poster Rapporteur Session:
TumorsSarcoma, CNS-S ATURDAY, M AY 7, 2011
compared to primary disease, tumor size, margin status, boost technique,or use of chemotherapy (neoadjuvant 19 pts, concurrent 30 pts) were notsignificantly associated with relapse or survival. Postoperative wound complications requiring additional surgical procedures occurred in 26 pts (37%).
There was a trend towards increasing wound complications among patientstreated with brachytherapy vs. IOERT (60 vs. 30%; p = 0.06), but other factors
such as use of chemotherapy or tumor size showed no association. Clinicallysignificant chronic complications included neuropathy (4 pts), lymphedema (3pts), and fracture requiring surgical fixation (1 pt).

12 oralINTRAOPERATIVE ELECTRON IRRADIATION FOR INTRACRANIAL
TUMOR: LONG-TERM OUTCOME IN A SINGLE INSTITUTION
EXPERIENCE
S. Usychkin1 , F. Calvo2 , J. Samblas1 , D. Ortiz de Urbina Ugarte1 , J.
C. Bustos3 , J. Gutierrez-Diaz3 , K. Sallabanda Díaz3 , C. Peraza4 , J. M.
Delgado4 , H. Marsiglia1
1
G RUPO IMO, Radiation Oncology Department, Madrid, Spain
2
H OSPITAL G REGORIO M ARAÑÓN, Department of Oncology, Madrid, Spain
3
G RUPO IMO, Department of Neurosurgery, Madrid, Spain
4
G RUPO IMO, Department of Medical Physics, Madrid, Spain
Purpose: To describe the feasibility and outcome of intraoperative electron irradiation during craniotomy for primary central nervous system malignancies.
Materials: From 1992 to 2002, 32 patients (p) were treated with an IORT
post-resection boost. Craniotomy was indicated for recurrent disease in 30
patients: 13 p post-surgery + radiotherapy; IORT parameters were: dose 800
cGy (2 p), 900 cGy (2 p), 1000 cGy (15 p), 1250 cGy (3 p), 1500 cGy (7 p),
1600 cGy (1 p) and 2000 cGy (2 p); energy 6 MeV (4 p), 6 MeV (5 p), 10
MeV (2 p), 12 MeV (2 p), 15 MeV (6 p), 18 MeV (13 p); applicator size: 5 cm
(22 p), 6 cm (8 p) and 7 cm (2 p). Postoperative external -beam radiotherapy(40-60 Gy) was added to 15 previously untreated patients. Postoperative
chemotherapy was administered to 14 patients.
Results: Gender distribution was: 18 males and 14 females. Age ranged
from 15 to 76 years old. Histological subtypes included: 5 oligodendrogliomas, 6 astrocytomas low grade, 21 astrocytomas high grade. Mediansurvival time for the entire group was 12 month (9 month high vs 96 months
low grade tumors). 9 patients survived more than 2 years. Long-term survivors include 4 patients at 95, 97, 144 and 187 months of follow-up. Functional, neurological and imaging long-term characteristics are under evaluations for IORT treatment parameter potential correlations.
Conclusions: IORT is a feasible technique during craniotomy for hemispheric tumors, including primary and recurrent central nervous systems malignancies. Long-term survivors are followed with disease control. Updated
results will be present.
13 oral
PREOPERATIVE RADIATION AND INTRAOPERATIVE ELECTRON
RADIOTHERAPY (IOERT) OR BRACHYTHERAPY FOR EXTREMITYSARCOMA
J. Ashman1 , M. Callister1 , C. Beauchamp2 , A. Schwartz2 , T. Fitch3 , L.
Gunderson1
1
M AYO C LINIC S COTTSDALE, Radiation Oncology, Scottsdale, USA
2
M AYO C LINIC S COTTSDALE, Orthopaedics, Scottsdale, USA
3
M AYO C LINIC S COTTSDALE, Hematology-Oncology, Scottsdale, USA
Purpose: Since 2002 at Mayo Clinic in Arizona (MCA), patients with extremity
soft tissue sarcoma (STS) have been treated with preoperative external beam
radiotherapy (EBRT) followed by surgery with either IOERT or brachytherapy.
This review updates and extends our previous reports with regards to outcomes and morbidity.
Materials: A retrospective review was performed of all patients at MCA withextremity STS treated with preoperative EBRT and intention of IOERT boost
using a mobile electron accelerator (Mobetron®). Patients (pts) with desmoid
tumors (n=3) were included. Patients with non-extremity sarcoma, prior EBRT
to the tumor site, or DM at presentation were excluded. Survival analysis was
performed according to the Kaplan-Meier method. Chi-square testing wasused for comparison between groups.
Results: Between January 2002 and December 2009, 71 consecutive pts
were treated with preoperative EBRT (median 50.4 Gy, range 30.6-50.4) followed by surgery and either an IOERT (56 pts; median 12.5 Gy, range 10-15)
or a brachytherapy (15 pts; LDR, 15 Gy-13 pts; HDR, 12 Gy/3 Fx-2 pts) boost
are analyzed for this review. With a median follow-up of 32 months (range
5-99 months), 3-year OS was 77% (Table 1). Pts with high grade disease
had significantly inferior OS at 3 years (100 vs. 69%; p = 0.012), which wascorrelated with an increased rate of DM (6 vs. 37%; p = 0.02). Relapse has
been observed in 25 pts (6 local; 4 nodal; 19 distant). The overall 3-year LC
rate was 90%, with both surgical margin status (R0 vs. R1, 92 vs. 77%; p =0.046) and disease site (lower vs. upper extremity, 92 vs. 72%; p = 0.039)
having significant associations with LC. Presentation with recurrent disease

P OSTER DISCUSSION

S9

and 75% respectively. Younger age showed a significant influence on local control (p=0.02, <50 years vs. ≥50 years) and a strong trend to significance on overall survival (p=0.06) and disease-free survival (p=0.08). Tenpatients (19%) experienced acute postoperative complications including delayed wound healing in nine patients with skin necroses requiring skin graftingin three of them, and surgical duodenal perforation resulting in fatal peritonitis
in one patient. EBRT-related acute toxicity included grade 1 in 9 patients(17%) and grade 2-3 epithelitis in 11 patients (21%). No cases of acute
grade 4 skin toxicity were observed. Late side-effects have been evaluated inthose patients surviving longer than 9 months from IORT (34 patients evaluable). Twelve patients (23%) developed grade 1-2 lymphedema and 9 patients (17%) showed grade 1-2 cutaneous fibroses. No cases of grade 3-5
late toxicity have been observed during the follow-up period. One case of lateneuropathy was observed but attributable to post-treatment medical manipulation of the limb rather than to surgery and/or IORT.
Conclusions: Combination of IORT and EBRT is feasible and the observed
results compare well with data collected from other different groups with similar patients that included local IORT as a component of the treatment.
15 oral
EXTREMITIES SOFT-TISSUE SARCOMAS (STS) TREATED BY
SURGERY, INTRAOPERATIVE RADIOTHERAPY (IORT) AND
EXTERNAL-BEAM RADIOTHERAPY (EBRT): ANALYSIS OF PROGNOSTIC FACTORS.
A. Montero1 , R. Hernanz de Lucas1 , A. Polo1 , D. Perez Aguilar2 , I. Sanchez
del Campo2 , E. Fernández Lizarbe1 , A. Hervas Moron1 , S. Sancho García1 ,M. C. Vallejo Ocaña1 , R. Morera López1 , A. Ramos Aguerri1
1
R AMON Y C AJAL H OSPITAL, Department of Radiation Oncology, Madrid,
Spain
2
R AMON Y C AJAL H OSPITAL, Department Of Orthopedic Surgery, Madrid,
Spain

Conclusions: Limb preservation and local control rates are generally quite
acceptable in this group of patients by virtue of combining preoperative EBRT
with surgery and either IOERT or brachytherapy. From our perspective, both
IOERT and brachytherapy are preferred boost techniques over EBRT. DM
rates remain significant in patients with high-grade lesions, and did not appear
to be impacted by the use of chemotherapy. Wound complications require
close collaboration with a skilled plastic surgery team but do not appear toresult in significant chronic problems for most patients.
14 oralINTRAOPERATIVE RADIOTHERAPY (IORT) COMBINED WITH
EXTERNAL BEAM RADIOTHERAPY (EBRT) FOR THE TREATMENTOF MUSCULOSKELETAL TUMORS.
A. Montero1 , A. Polo1 , R. Hernanz de Lucas1 , I. Sanchez del Campo2 , D.
Perez Aguilar2 , E. Fernández Lizarbe1 , L. Cabañas3 , A. Hervas Moron1 ,S. Sancho García1 , M. C. Vallejo Ocaña1 , R. Morera López1 , A. Ramos
Aguerri1
1
R AMON Y C AJAL H OSPITAL, Department of Radiation Oncology, Madrid,
Spain
2
R AMON Y C AJAL H OSPITAL, Department Of Orthopedic Surgery, Madrid,
Spain
3
R AMON Y C AJAL H OSPITAL, Department of General Surgery, Madrid,
Spain
Purpose: The aim of the present study is to review our own experience using intraoperative radiation therapy (IORT) in combination with external beam
radiotherapy (EBRT) in the multidisciplinary management of musculoskeletalsarcomas.
Materials: From May 2004 to June 2010, 52 consecutive patients with pathologically confirmed bone or soft tissue sarcoma were prospectively enteredinto a data registry of IORT as a part of the multidisciplinary treatment of musculoskeletal sarcomas. Patients’ registry included 24 females and 28 maleswith a median age of 50 years (range 16-80 years). Forty-three patients
presented with primary tumors (83%) while 9 cases (17%) were local recurrences of previously treated sarcomas. Histological subtypes treated were:
liposarcoma in 15 patients (29%), leiomyosarcoma in 10 patients (19%), sarcoma not otherwise specified (NOS) in 7 patients (13%), malignant fibrous
histiocytoma in 4 patients (8%), aggressive fibromatosis in 4 patients (8%),
Ewing’s sarcoma in 4 patients (8%), chondrosarcoma in 4 patients and dermatofibrosarcoma, clear-cell sarcoma, malignant schwannoma and osteosarcoma in 1 patient each. Sarcomas treated with IORT were located in the lower
extremity in 34 patients (65%), retroperitoneum in 7 patients (13%), upper
extremities including shoulder girdle in 5 patients (10%), pelvis in 4 patients(8%) and superficial trunk in 2 patients (4%).
Results: With a median follow-up of 20 monts (range 3-74 months), 5-year
actuarial overall survival (OS) and disease-free survival (DFS) are 70% and62%. Three patients (6%) developed local failure as the sole site of relapse, 7 patients (13%) presented distant relapse without evidence of tumor
recurrence on the primitive location and 3 patients (6%) showed both local
and distant reappearance of sarcoma. The actuarial 5-year locoregionalfree survival (LRFS) and distant-metastases free-survival (DMFS) are 80%

Purpose: To analyze the outcomes and to identify prognostic factors in patients with extremities soft tissue sarcomas receiving IORT as a part of multidisciplinary treatment.
Materials: From May 2004 to June 2010, 34 consecutive patients with pathologically confirmed soft tissue sarcoma of the extremities were prospectively
entered into a data registry of IORT. Patients’ registry included 15 females
and 19 males with a median age of 50 years (range 16-80 years). Majority of patients presented with primary tumors (32, 94%) while 2 cases (6%)
were local recurrences of previously treated sarcomas. Histological subtypes
were: liposarcoma 11p (32%), leiomyosarcoma 9p (26.5%), sarcoma not otherwise specified (NOS) 7 patients (21%), malignant fibrous histiocytoma 2p(6%), aggressive fibromatosis 2p (6%), and dermatofibrosarcoma, clear-cellsarcoma and malignant schwannoma in 1p each. Sarcomas were located inlower extremities in 29p (85%) or upper extremities 5p (15%). All the patients
underwent surgical resection considered as R0 in 32p (94%), R1 1p (3%) or
R2 1p (3%). IORT (median dose 15 Gy, range 15-20 Gy) was followed by
EBRT in 31p (median dose 50 Gy, range 39-60 Gy).
Results: With a median follow-up of 17 months (range 3-74 months), 3-year
actuarial overall survival (OS), disease-free survival (DFS), locoregional-freesurvival (LRFS) and distant-metastases free-survival (DMFS) are 77%, 65%,84% and 72% respectively. Log-rank tests carried-out on possible prognostic factors identified an advanced stage at diagnoses as negative factor for
OS, DFS and DMFS (p<0.0001 for all comparisons) and the negative impactof a delay between IORT and complementary EBRT on DFS (p=0.036) and
DMFS (p=0.056). Analysis also evidenced that age below 50-y had a strong
trend to significance on OS (p=0.069) and DFS (p=0.059). A significant association was found between local relapse and the probability of developing distant metastases (p=0.005) as well as between the presence of distantmetastases and the overall survival (p<0.0001). Seven patients (21%) experienced acute postoperative complications including delayed wound healing
in 6 patients with skin necroses requiring skin grafting in 2 of them. EBRTrelated acute toxicity included grade 1 in 7 patients (21%) and grade 2-3
epithelitis in 9 patients (26.5%). No cases of acute grade 4 skin toxicity wereobserved. Late side-effects have been evaluated in those patients surviving
longer than 9 months from IORT (29 patients evaluable). Ten patients (34%)
developed grade 1-2 lymphedema and 9 patients (31%) showed grade 1-2
cutaneous fibroses. No cases of grade 3-5 late toxicity have been observed
during the follow-up period. One case of late neuropathy was observed but
attributable to post-treatment medical manipulation of the limb rather than tosurgery and/or IORT.
Conclusions: Extremities STS benefit from multimodality treatment including IORT. Efforts made to improve local control appear transcendent as local
relapse are directly related with development of distant metastases and thiscircumstance with overall survival.

S 10

P OSTER DISCUSSIONS ATURDAY, M AY 7, 201116 oral18 oral

EXPERIENCE WITH IORT AS INTRAOPERATIVE INTENSIFICATION THERAPY IN THE TREATMENT OF LOCALLY ADVANCEDRETROPERITONEAL AND PELVIC SARCOMAS
E. Velasco Sánchez1 , J. L. Garcia-Sabrido1 , F. Calvo2 , L. Gómez Lanz1 , L.
Gonzalez-Bayon1 , L. Rodríguez-Bachiller1 , B. Díaz-Zorita1 , E. Ruiz Úcar1 ,P. Álvarez de Sierra1
1
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Oncological
Surgery, Madrid, Spain
2
H OSPITAL G REGORIO M ARAÑÓN, Oncology and Radiotherapy, Madrid,
Spain

KYPHO-IORTINTRAOPERATIVERADIOTHERAPYDURINGKYPHOPLASTY FOR VERTEBRAL METASTASES: FIRST CLINICALRESULTS
T. Reis1 , F. Schneider1 , G. Welzel1 , R. Schmidt2 , U. Obertacke2 , F. Wenz1
1
U NIVERSITY M EDICAL C ENTER M ANNHEIM, Department of Radiation
Oncology, Mannheim, Germany
2
U NIVERSITY M EDICAL C ENTER M ANNHEIM, Department for Orthopaedics
and Trauma Surgery, Mannheim, Germany

Purpose: Sarcomas are rare tumors that develop from mesenchymal cells.
Their management is difficult due to their changing histology, location andbehavior. Our purpose is to discuss the role of IORT in the therapeutic planification of this disease, and present the experience of our institution in thetreatment of locally advanced retroperitoneal and pelvic sarcomas with radical surgery and IORT.
Materials: We present a series of 42 consecutive patients treated in our institution with radical surgery plus IORT, with a diagnosis of locally advanced
retroperitoneal or pelvic sarcoma. We analyze survival, disease free survival,
morbidity and mortality, and compare our results with those found in the literature to asses the potencial benefits of this protocol of treatment.
Results: The complete resection rate was 92%, which includes 13 major vascular resections. The survival rate was 64,7% at 5 years and the disease freesurvival rate was 38,7%. The estimated disease free survival median timewas 28 months. The morbidity and mortality was according to the complexityof the procedure and similar to other comparable surgical techniques
Conclusions: IORT associated with radical surgery seems to improve theoutcomes of surgery alone in terms of local control of the disease, and potencially survival in locally advanced retropertioneal and pelvic sarcomas. The
security of the protocol is according to the complexity of the procedure, withmorbidity and mortality within acceptable limits.
17 oral
USE OF INTRAOPERATIVE RADIATION THERAPY (IORT) FOR
UPPER EXTREMITY SOFT TISSUE SARCOMAS: ANALYSIS OFDISEASE OUTCOMES AND TOXICITY
J. Call1 , S. Stafford1 , I. Petersen1 , M. Haddock1
1
M AYO C LINIC, Department of Radiation Oncology, Rochester, USA
Purpose: To review overall survival (OS), disease control and toxicity for patients who received IORT as a component of therapy for upper extremity sarcoma.
Materials: 61 patients received treatment that included external beam radiation therapy (EBRT), surgery, and IORT (60 using electrons and 1 treatedwith high-dose-rate brachytherapy) with or without chemotherapy for upper
extremity tumors from 1990 to 2009. Eight of these patients were treated forrecurrent disease (4 of which had received radiation at initial diagnosis). Median age was 50 years (range 13 95 years). Median follow-up was 5.9 years.
11 patients had gross (R2) or microscopic (R1) disease documented at thetime of IORT. IORT doses ranged from 750-2000 cGy. EBRT doses ranged
from 1980-5400 cGy. Kaplan-Meier estimates for OS, central control (CC),local control (LC), and distant control (DC) were obtained. Cox regression
analysis was used to test the association of dose on local control.
Results: OS at 5 and 10 years was 72% and 58%, respectively. LC at 5 and10 years was 91% and 88%, respectively. Of the 5 patients who failed locally,
2 ultimately had an amputation. Four patients were known to have metastatic
disease at the time of IORT. For the other 57 patients, DC was 80% at 5
years and 77% at 10 years. Estimated CC was 93% at 5 years and 90% at
10 years. Patients treated for recurrent disease had inferior OS comparedto others at 5 years (63% vs. 74%, p=0.02) and lower LC at 5 years (67%vs. 94%, p<0.01). There was no association between IORT dose and local
control (p=.23). Patients with R1 or R2 resections had LC at 5 years of 100%and at 10 years of 86% compared to 89% and 89% at 5 and 10 years for R0
patients (p=.98). Severe toxicity related to treatment was noted in 4 patients(7%). Of these 4 patients with severe events, 2 had wound complications,
one had avascular necrosis of the humerus, and one had severe peripheral
neuropathy.
Conclusions: Inclusion of IORT in the treatment of upper extremity sarcoma
was associated with excellent local control, limb preservation and survival.
Local control rates were excellent in patients with positive margin resection.
Distant relapse remains as the main pattern of failure and is predicted bytumor size. Patients treated for recurrent disease had worse outcome but
local control and limb preservation was achievable in the majority.

Purpose: Kyphoplasty is an effective procedure providing immediate stability and alleviate pain in vertebral metastases. However it has no provenanticancer effect. To prevent early regrowth these patients receive a postoperative fractionated radiotherapy, which is associated with long treatment
duration. Therefore we established a new approach to deliver intraoperative
radiotherapy (IORT) during kyphoplasty to shorten the treatment time andreach immediate stability and sterilization of the metastases.
Materials: Under general anesthesia a bipedicular access into the vertebra was chosen with insertion of specially designed metallic sleeves. Thesesleeves were used to guide the electron drift tube of the miniature X-ray generator (INTRABEAM® , Carl Zeiss Surgical, Oberkochen, Germany), which
was protected by a specially designed applicator. A radiation dose of 8 Gy
in 5 mm distance (50 kV X-rays) was delivered during about 2 minutes. Afterradiation the INTRABEAM® system was removed and the kyphoplasty wascompleted according to standard procedure. Since August 2009, 18 patientswith instable or painful spinal metastases received Kypho-IORT. Of these patients, 3 underwent procedure at two vertebral levels. The median age was
63 years (range, 43-73).
Results: Kypho-IORT was successfully performed in 18 of 21 vertebral lesions (86%). No severe complications occurred during or early after surgery.
The median pain score using a visual analog scale improved from 5/10 before the procedure to 2,5/10 at day 1 and to 0/10 6 weeks after the procedure(p<0,001). The use of pain medication also decreased after Kypho-IORT(68% before vs. 30% 6 weeks after the procedure). Stable disease (SD)within the irradiated vertebral body was seen in 14 patients (93%), local progressive disease (PD) in one patient (7%). No re-irradiation due to local PD
or pain recurrence was necessary within the median follow up of 5 month.
In contrast to this 11 of 15 patients (73%) developed progressive visceralmetastases or further bone metastases.
Conclusions: The combination of kyphoplasty and IORT is well tolerated
with good local control and adequate improvement of pain. A dose escalation
study to establish the optimal dose has been initiated.
19 oralISIORT-EUROPE DATA REGISTRY: MAIN CHARACTERISTICS OFIORT TREATMENTS
M. Krengli1 , F. Sedlmayer2 , F. Calvo3 , S. Maluta4 , F. Checcaglini5 , R.
Corvò6 , H. Marsiglia7 , E. G. Russi8 , R. Maurizi Enrici9 , A. Ciabattoni10 , W.
Polkowski11 , A. Kuten12 , C. Iotti13 , F. Coghetto14 , V. Valentini15
1
U NIVERSITY OF P IEMONTE O RIENTALE, Novara, Italy
2
L ANDESKLINIKEN S ALZBURG , SJS, Salzburg, Austria
3
H OSPITAL G REGORIO M ARAÑÓN, Madrid, Spain
4
A ZIENDA O SPEDALIERA U NIVERSITARIA I NTEGRATA, Verona, Italy
5
H OSPITAL N UOVO C ITTA DI C ASTELLO, Citta di Castello (Perugia), Italy
6
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Genova, Italy
7
G RUPO IMO, Madrid, Spain
8
A ZIENDA O SPEDALIERA S. C ROCE E C ARLE, Cuneo, Italy
9
U NIVERSITÀ L A S APIENZA , II FACOLTÀ, Rome, Italy
10
O SPEDALE S AN F ILIPPO N ERI, Roma, Italy
11
M EDICAL U NIVERSITY OF L UBLIN, Lublin, Poland
12
R AMBAM M EDICAL C ENTER, Haifa, Israel
13
A RCISPEDALE S. M ARIA N UOVA, Reggio Emilia, Italy
14
O SPEDALE DI T REVISO, Treviso, Italy
15
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Roma, Italy
Purpose: A joint analysis of data from centres within the ISIORT-Europe program was performed to investigate the role of intra-operative radiotherapy(IORT) and contribute to homogenize treatment modalities.
Materials: All ISIORT-Europe centres were invited to record the data of
their IORT treatments using the appropriate file available at the website
www.isiort.org/htm/isiort_europe.htm and send them to the data centre. All
information (institution, patient data, tumour data, treatment modality) were
therefore collected in a common database to analyse clinical and technicalaspects of the treatments.
Results: At present, 2230 cases from 10 Italian, 2 Spanish, 1 Austrian, 1 Polish and 1 Israeli centres have been collected. Table 1 shows, as an example,
some technical aspects of the treatment data.

S ATURDAY, M AY 7, 2011

P OSTER DISCUSSION

S 11

Conclusions: The availability of data from several centres active in IORT
treatments may allow to perform data analysis useful to disseminate knowledge about clinical and technical aspects of this radiation modality and to
dispose a basis for further clinical multicenter trials.

Poster Rapporteur Session: Physics, Techniques,
Dosimetrics I
20 poster
IN VIVO DOSIMETRY WITH MOSFETS DURING INTRA-OPERATIVERADIOTHERAPY FOR PARTIAL BREAST IRRADIATION
A. Petoukhova1 , K. van Wingerden1 , P. Koper1 , H. Ceha1 , A. Verbeek-deKanter1 , A. Marinelli2 , J. van der Sijp2 , H. Struikmans1
1
R ADIOTHERAPY C ENTRE W EST, The Hague, Netherlands
2
M EDICAL C ENTER H AAGLANDEN, Department of Surgery, The Hague,
Netherlands
Purpose: In vivo dosimetry is an important tool to check whether the delivered dose and the planned dose are the same. For intra-operative radiotherapy (IORT) in partial breast irradiation (PBI), this is especially relevant
because the dose is delivered in a single fraction. The purpose of this study
was to compare the given dose to the planned dose in breast conserving
therapy.
Materials: During the period May 2010 - October 2010, nineteen elderly(60+) patients, diagnosed with breast cancer (tumour diameter < 3 cm)
were treated with IORT while in vivo dosimetry with MOSFETs (metal-oxide
semiconductor field-effect transistors, Thomson Nielsen TN-502RD) was performed. For each patient, PBI with a total dose of 21 Gy at 90% was given
during the operation according to the ELIOT study (1). All patients were irradiated with electron beams generated with an IORT dedicated mobile accelerator (Mobetron, INTRAOP, USA). The in vivo dose measurements were done
by attaching the first detector under the bolus at the end of the applicator andthe second detector attached behind the protection plate (6 mm aluminium
plus 3 mm copper), which was used to shield the thorax. Calibration of the
MOSFET detectors was determined by measuring the absolute dose with a
Roos ionization chamber on the same day. The calibration measurements
were performed with the electron beams of the Mobetron in a homemade
PMMA phantom at dose maximum for each energy. The usability of MOSFETs for IORT was studied before (2).
Results: The results of in vivo dosimetry are shown in the table. For patient
10, the measured entry dose deviates by -9.1%, probably because of multiple
relocations of the applicator. The used applicator diameter range between 4
cm and 6.5 cm. The tip angle of the applicator was 0, 15 and 30 for 58%, 5%
and 37% of patients, respectively.

Conclusions: In vivo MOSFET dosimetry during IORT was successful for
PBI. The measured entry dose for the breast tissue agrees within 1.6% withthe expected dose. The results of MOSFET measurements behind the protection plate are lower than calculated based on the transmission measurements in the primary beam through the plate. For our patients, the dose to
the thoracic wall and lungs was lower than 2 Gy even if 12 MeV was applied.
1. Intra M, Luini A, Gatti G, et al, Surgery (2006) 140:467-71.
2. J. Penninkhof, K. van Wingerden, J. van Egmond, et al, Radiother Oncol (2008), 88 (Supplement 2),S387.

21 oral
CHARACTERIZATION OF REINFORCED MICRO MOSFETS:
GROUPING OF CALIBRATION COEFFICIENTS AND DOSE RESPONSE
J. Lopez-Tarjuelo1 , J. D. Quirós Higueras1 , N. de Marco-Blancas1 , A.
Santos Serra1 , A. Bouché-Babiloni2 , C. Ferrer Albiach2 , V. Morillo-Macías2
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Servicio deRadiofísica y Protección Radiológica, Castelló de la Plana, Spain
2
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Servicio deOncología Radioterápica, Castelló de la Plana, Spain

1

Purpose: Intraoperative Electron Radiotherapy (IOERT) treatment consistsof single fraction irradiation. Therefore, in vivo absorbed dose monitoring isdesirable for verification, recording and correction. MOSFET detectors havebeen investigated for these purposes. Reinforced MOSFETs are made by
manufacturer to enhance the mechanical endurance of MOSFETs. As weare concerned that MOSFETs are expendable and linac occupation is usually
very high, we have characterized our dosimetric system with the intention of
optimizing their use as the first stage of reporting in vivo absorbed doses in
our treatments.
Materials: Three reinforced MOSFET model mobile MOSFET TN-502RDMH (Best Medical Canada Ltd., Ontario, Canada) have been calibrated with an
Elekta Precise linac. They were put in their calibration jig and irradiated with a
10x10 cm2 applicator at the depth corresponding to the maximum dose withenergies of 4, 6, 9, 12, 15 and 18 MeV. Calibration coefficients (CC) wereanalyzed to group them in order to determine if the same coefficient could beapplied to various energies in future calibrations. Dose response deviationfrom linearity and dose rate response have been assessed too.
Results: ANOVA analysis of the calibration coefficients concluded that theCCs for 6, 9 and 12 MeV were compatible (p ≥ 0.239), which means that it
is possible to calibrate one MOSFET with one of these energies and apply
its CC to the other two energies without taking more measurements. The
same happened with 15 and 18 MeV (p ≥ 0.459). Calibrations for 4 MeV
should be performed separately.Lack of reproducibility was better than 0.8%
when considering 90% of all CCs.Deviation from linearity was measured to
be within 2% from 20 to 400 monitor units (MU).Dose rate response variation
was better than 0.5% from 50 MU/min to 400 MU/min.
Conclusions: Dosimetric characterization of reinforced micro MOSFETs has
been presented as the first stage of dose delivery verification in IOERT. It is
possible to calibrate each MOSFET for only 6 MeV and measure 9 and 12
MeV with the same CC and do the same with 15 and 18 MeV. These features
allow us to save linac time and to increase the MOSFETs lifetime.Longer
irradiations properly optimized should be considered to test linearity above
400 UM because damage to the detectors accumulates.Lack of reproducibility and lack of constancy with variable dose rate under calibration conditions
are lower than the allowed deviation during absorbed dose verification in otherradiotherapy techniques.Supported by grants PSE-300000-2009-5 and IPT300000-2010-3. Ministerio de Ciencia e Innovacipanish Government.

S 12

P OSTER DISCUSSIONS ATURDAY, M AY 7, 201122 oral23 oralIN VIVO DOSIMETRY BY EBT2 GAFCHROMIC FILMS TO VALIDATEA IORT PROCEDURE
S. Magi1 , R. Romagnoli1 , M. Palombarini1

COMPARISON OF IONISATION AND CHEMICAL DOSIMETRYFOR THE CALIBRATION OF A HEAVILY PULSED ELECTRONACCELERATOR
F. Hensley1 , K. Wagenknecht1 , P. Sharpe2 , C. Pychlau3 , F. Roeder4 , C.

1
AUSL DI B OLOGNA , O SPEDALE B ELLARIA, Department of Medical
Physics, Bologna, Italy

Purpose: In 2009 our centre introduced IORT as anticipated boost in earlystage breast cancer.We use Sordina’s 10 MeV LIAC and, to protect underlying organs at risk, we use Sordina’s shielding disk, made of 3 mm PTFE and3 mm INOX AISI LN 316 steel.The aim of this study is to validate our IORT
procedure by using EBT2 gafchromic films for in vivo dosimetry.
Materials: We measured Entrance and Exit doses by EBT2 gafchromic films
and compared them with the expected values.The calibration of the film wascarried out on a 10 MeV electron beam from a conventional LINAC (Elekta
Precise), using a plane parallel chamber (PTW Markus Chamber) for absolute dose measurements.The 16 bit signal from the films was acquired by
a commercial flat-bed scanner (EPSON 10000XL: white light, CCD reading
system), and filtered in the green channel.Monitor Units were corrected fordaily pressure and output (the temperature of the head was assumed to beconstant).Surface Dose (DSUP) was measured by a small piece of EBT2
gafchromic film, wrapped in a sterile drape and put at the exit of the collimator.Exit Dose (DD ) was measured by a circular cut of gafchromic filmof the same dimensions of the shielding disk, attached on it and envelopedin a sterile drape.Expected Entrance Dose (De-in) is the dose prescribed by
the Radiotherapist at the depth of maximum dose (Dmax) Expected Exit Dose
(De-ex) is the dose estimated at the depth of the disk. The depth is measured
by the surgeon and the dose is derived by correcting the dose prescribedat Dmax for the PDD value.Measured Entrance Dose (Dm-in) at Dmax is
obtained from the gafchromic reading at the surface (DSUP), corrected by
FS®I, the measured multiplying factor, which gives the dose at Dmax: Dmin = (FS®I )d,En. DSUPMeasured Exit Dose, (Dm-ex), is obtained correcting
the Exit Dose measured on the disk (DD) by the measured backscatter factorof the Disk (BS): Dm-ex =(1-(BS)En) . DD.The overall uncertainty of the dosevalues determined by this method is estimated to be around 4% (1SD).
Results: For the first 23 patients, the (mean difference ± 1SD) between expected and measured entrance doses is (-0.6% ± 3.4%).Between expected
and measured exit doses is (+5,0% ± 7.7%).The analysis was performed
also grouping the results per collimator: no correlation or systematic effects
were observed.

Timke4 , G. Felici5
U NIV. K LINIKUM H EIDELBERG, Heidelberg, Germany
2
N ATIONAL P HYSICAL L ABORATORY, Teddington, United Kingdom
3PTW-F REIBURG, Freiburg, Germany
4
U NIVERSITY OF H EIDELBERG, Heidelberg, Germany
5
SORDINA SPA, Mogliano, Veneto, Italy

1

Purpose: Some newer electron linear accelerators (linacs) dedicated for intraoperative radiation therapy (IORT) produce a slowly pulsed electron beam(with repetition rates around 10-40Hz) at extremely high dose per pulse(around 0.3 to 4 cGy per pulse). These pulsation conditions may cause considerable difficulties in ionisation dosimetry. In pulsed radiation, the signal ofan ionisation chamber (IC) is subject to recombination losses. Most dosimetry protocols recommend correction of this effect by a formalism developed
by Boag [1]. However, due to simplifications, Boag’s formalism may largely
overestimate the recombination correction for the high doses per pulse fromthe mentioned linacs [2]. A recent publication [3] suggests a method whichshould provide a more accurate correction. However this method includes
fits of model parameters to saturation curves and probably depends strongly
on the geometry of the ionisation chamber. It must therefore be adjusted toeach individual chamber. Therefore it is recommendable to verify ionisation
dosimetry for the pulsed linacs by reference dosimetry using a method independent of pulse rate and dose per pulse. Chemical dosimetry such as
alanine and thermoluminesent dosimeters (TLD) should provide such independence.
Materials: Dose measurements in a water phantom were performed for the
5 energies of a Liac accelerator ( 4, 6, 8, 10 MeV) with an Advanced Markus
parallel plate ionisation chamber and simultaneously with either alanine or
LiF TLDs. Measuring depths were the calibration reference depth zref as
defined by IAEA TRS 398 and DIN 6800-2 (2008) and depths corresponding to 0.8, 0.5 and 0.25 Dmax. The measurements correspond to pulses
between 0.07and 3.8 cGy/pulse. The data of the three dosimeters was independently evaluated by NPL (alanine), PTW-Freiburg1 (TLDs), and our hospital (IC data). The IC data was corrected for recombination losses applying
the formalism by Laitano[3]. Otherwise, corrections followed the recommendations of DIN 6800-2 (2008).
Results: At zref, all measurements show good agreement within 2.4% for allenergies. At this depth IC and TLDs agree within 0.7%. At 0.5 Dmax, the IC
and TLD measurements agree within better than 1% (one case 2.4%). For the
positions deeper than zref, the alanine measurements show larger deviations
from the IC data which appear to grow (up to 16%) with decreasing electronenergy. No correlation was found to dose per pulse either for the deviationsof alanine or of TLDs in comparison to the IC.
Conclusions: At calibration depth, both alanine and TLD appear to besuitable chemical dosimeters for reference dosimetry of the pulsed electron
beams of the Liac accelerator. At larger depths in material, the observed
different response of the three dosimeter systems needs further investigation.References:1. Boag, J.W. (1966): Ionization Chambers. In: Attix, F.H.,
Roesch, W.C., Eds. Radiation Dosimetry Vol. 2, 172; Academic Press2.
Piermattei etal.: The saturation loss for plane parallel ionization chambers at
high dose per pulse values. Phys Med Biol 45 (2000) 1869-18833. Laitano
etal.: Charge collection efficiency in ionization chambers exposed to electron
beams with high dose per pulse. Phys. Med. Biol. 51 (2006) 64196436
24 posterConclusions: The good agreement between measured and expected entrance dose confirms the reliability of our MUs calculation method.On the contrary, the significant difference between expected and measured exit doses
shows that many unpredictable factors affect this data: uncertainty on depth
estimation, irregular surfaces, accumulation of biological fluid, tissue density
and temperature, machine/patient setup, uncertainty of backscatter factor&
Exit dose measurements and their influencing factors are now under further
investigation.

IN VIVO DOSIMETRY AND MONTE CARLO SIMULATION FOR IORTBREAST CANCER TREATMENT
F. Cavagnetto1 , S. Agostinelli1 , G. Taccini1 , A. Soriani2 , L. Strigari2 , G.
Iaccarino2 , M. D’Andrea2 , L. Bellesi2 , G. Felici3 , A. Ciccotelli3
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Department ofMedical Physics and Radiation Safety, Genova, Italy
2
R EGINA E LENA C ANCER I NSTITUTE, IFO U.O.C.LABORATORIO DI FISICA
E SISTEMI ESPERTI, Roma, Italy
3
S ORDINA S. P.A., Saonara (PD), Italy
Purpose: In vivo dosimetry data measured on 70 patients with MOSFET
detectors have been acquired during IORT breast treatments. In case of verythin targets (<10 mm) measured dose exceed the expected value of about
8%. A further investigation is mandatory to explain these results.
Materials: Treatments were performed using a mobile Linear accelerator with
4, 6, 8, 10 MeV electron beams (LIAC, Sordina S.p.A., Italy), using cylindrical applicators with diameters ranging from 4 to 10 cm. A steel-PTFE plate(3mm+3mm) was placed between the deep face of the residual breast andthe pectoralis muscle to minimize the thoracic wall irradiation. MOSFET (BestMedical, Canada) detectors were used to determine the dose collected by the
deeper part of the target, and were placed inside a thin and sterile catheter,
fixed at the centre of the PTFE side of the disk before the insertion in the

S ATURDAY, M AY 7, 2011breast1 . The detectors were calibrated at 4 Linac electron beam energies
in the same geometry of daily dosimetry check, with an error lower than 3%
for all the energies. MOSFET readings were corrected for depth and isodose normalization. Monte Carlo simulation of LIAC was implemented, using EGSnrc/BEAMnrc code2 . Different targets have been investigated, using
cylindrical and step-shaped geometries.
Results: 12% of MOSFET readings are higher than 10%. In order to investigate these abnormal data, measurements with different set up were performed. MOSFET angular response dependence can be excluded because
differences are less than 6% in the range 0-180◦ . Dose increase due tobackscatter radiation from radioprotection disc (RPD) in case of a thin tissue
layer on the plate can also be excluded: measurements with MOSFET and
Gafchromic film, acquired in a Water phantom at different depths with andwithout RPD under the dosimeter, give differences lower than 5%. We havemeasured differences higher than 10% using a set up with different tissue
layers and air interposed (for example using a glove partially filled of water).
Monte Carlo simulations results confirms measured data. E-beam low energies components, which are greater in the initial millimetres, must be taken
into account in MOSFET output.
Conclusions: Dose distributions knowledge in IORT breast treatment
with thin layers has been improved after the combined actions of invivo dosimetry and Monte Carlo simulations. 1 F.Cavagnetto, S.Agostinelli,
R.Corvo’, S.Garelli, M.Guenzi, M.Gusinu, G.Taccini "In vivo dosimetry in
IORT for breast irradiation: the preliminary experience of IST in Genoa" Abstract - 6th International Conference of ISIORT 20102 L.Strigari, G.Iaccarino,
M.D’Andrea, L.Bellesi, G.Felici, A.Ciccottelli, M.Benassi, A.Soriani, Scientificpaper - 6th International Conference of ISIORT 2010
25 oralPENCIL BEAM FOR ELECTRON INTRAOPERATIVE RADIOTHERAPY. RESULTS OF DOSE CALCULATIONS IN HETEROGENEOUS
MEDIA.
J. A. Calama Santiago1 , A. Garcia-Romero2 , D. Lardiés Fleta3 , M. A. Infante
Utrilla1 , J. Lopez Tarjuelo4 , C. Ferrer Albiach4 , C. Serrano Navarro3 , E.
Lavado Rodriguez1
1
C LINICA L A L UZ, Madrid, Spain
2
H OSPITAL C LINICO U NIVERSITARIO G ONZALO B LESA, Zaragoza, Spain
3
T ÉCNICAS R ADIOFÍSICAS , S.L., Zaragoza, Spain
4
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Castelló de laPlana, Spain
Purpose: To determine the accuracy of dose calculations in heterogeneous
media of a pencil beam algorithm for electron intraoperative radiotherapy(IORT).
Materials: Algorithm modeling was carried out by Tecnicas Radiofisicas(Zaragoza, Spain) adapting a modified Hogstroms pencil beam implemented
in treatment planning system (TPS) PCRT3D for external radiotherapy. Thismodel was previously verified for dose calculation in water for IORT and wasfound to be in close agreement with diode and films measurements. The algorithm use CT-modified stopping and scattering powers relatives to water
to correct for heterogeneities, using effective depths and proper Gaussian
widths, within the limitations of semi-infinite layer approximation. In order tocheck it, international quality assurance protocol tests for TPS were adapted
to IORT with different heterogeneities configurations, more demanding thanthe ones used for clinical practice: solid water step, lung (type chest wall andmediastinum-lung), bone and shielding disks for breast IORT. These tests
were performed for different applicator sizes, bevel angles and beam energy.
Gafchromic EBT2 radiochromic films were used for dose measurements in
Elekta Precise and Varian 21EX linacs.
Results: Different profiles and isodoses curves were obtained, according todifferent heterogeneities setups. For profiles, lack of accuracy was kept within
3% or 4% in solid water step, lung and bone type heterogeneities with bevel
0 applicators; more accurate than others pencil beam algorithms describedin the literature. Discrepancies were higher for bevel angles, but evaluationof dose distributions showed that more than 95% of the points passed the
gamma test with 4% in dose and 4 mm in distance. The main limitation appeared on top of the shielding disk, because pencil beam algorithm cannot
model backscatter radiation. Nevertheless, the modeling of the attenuation
underneath the disk was in good agreement with measurements.

P OSTER DISCUSSION

S 13

Conclusions: Pencil beam is able to model IORT beams for dose calculation,even in heterogeneous media, and supposes an important advance from previous IORT dosimetric calculations based in water measurements, which isthe current state of the art in the field. With this work, we have completed theverification of the algorithm implemented in radianceTM TPS by GMV (Madrid,
Spain). The authors expect that further research with the Montecarlo algorithm can improve the limitations of the semi-infinite layer approximation andpoor backscattering modeling. Supported by grant PSE-300000-2009-5. Ministerio de Ciencia e Innovacipanish Government and FEDER founds.

Poster Rapporteur Session: Physics, Techniques,
Dosimetrics II
26 oralMONTE CARLO SIMULATIONS TO IMPROVE INTRA-OPERATIVERADIATION THERAPY DOSE CALCULATIONS IN CLINICAL SETTING
L. Strigari1 , G. Iaccarino1 , M. D’Andrea1 , L. Bellesi1 , G. felici2 , A. ciccotelli2 ,M. Benassi1 , A. Soriani1
I STITUTO R EGINA E LENA - IFO, Roma, Italy
2
S ORDINA S. P.A., Saonara (PD), Italy

1

Purpose: To calculate the input energy spectrum of two types of Intraoperative radiotherapy (IORT) mobile linear accelerator (mLINAC) using theMonte Carlo codes OMEGA-BEAMnrc and DOSXYZnrc and dosimetric datain order to determine the input data of Monte Carlo simulation and to calculate
the dose distribution using the CT images of patients who undergo IORT.
Materials: The treatment heads design data of two mLINACs and experimental dose data measured in water were provided by the manufacturer(SORDINA S.p.A., Padova, Italy). The electron beams energies of the firstmLINAC (75µm brass target) were 4, 6, 8 and 10 MeV, those of the second(820µm Aluminum target) were 6, 8, 10 and 12 MeV. The beam is collimatedby PMMA cylindrical applicators with diameters ranging from 30 to 100 mm.
To reconstruct the unknown energy spectrum monoenergetic beams with energies ranging from 2 to 14.6 MeV binned in 0.1 MeV steps have been simulated for each applicator. The dose statistical uncertainty was kept around
0,5%. A maximum likelihood optimization routine was used along with thecorresponding measured profiles to obtain the weight of each energy bin.
The optimized spectrum has been used as input of Monte Carlo code to calculate dose distributions based on CT images of patients who undergo IORT
using both mLINACs.
Results: The optimized energy spectrum reproduces the measured depth
and off-axis dose profiles in water to better than an overall 1,6 % and to better
than 0.5% between the build-up and the practical range for both LINACs.
The computed output factors agreed with the measured ones within 2% withworse agreement for the smaller applicators and lower energies, probably
due to measurement uncertainties. Based on optimized energy spectrum,
the Monte Carlo code has been used to calculate dose distribution using
both mLINACs and the CT images of 4 patients, one for each of the tumoursites/patologies that most frequently require a IORT treatment (breasts, headand neck, prostate and sarcomas).
Conclusions: A better characterization of the electron beam in IORT techniques arises from the need for a treatment planning system to be introduced
into clinical practice for a more accurate evaluation of the dose distribution. In
this work, Monte Carlo simulations were used to calculate the energy spectrum from measured data. The Monte Carlo simulation also allows us to calculate the dose distributions in IORT patients based on CT images and both

S 14

P OSTER DISCUSSIONmLINAcs. Monte Carlo simulation dose distributions can be also used as
benchmark of treatment planning systems and to help physicians and physicists in the treatment optimization when critical structures cannot be at all
removed or shielded during IORT delivered using mLINAcs.
27 oralA NEW TREATMENT PLANNING SYSTEM FOR INTRA-OPERATIVERADIOTHERAPY (IORT)
M. D’Andrea1 , S. Carpino1 , G. Iaccarino1 , L. Bellesi1 , G. Felici2 , A.
Ciccotelli2 , M. Benassi1 , A. Soriani1 , L. Strigari1
1
N ATIONAL C ANCER I NSTITUTE R EGINA E LENA, Laboratory of Medical
Physics and Expert Systems, Rome, Italy
2
S ORDINA S. P.A., Technical Division, Saonara (PD), Italy
Purpose: The main concern of Intra-Operative Radiotherapy (IORT) is thereliable assessment of the dose distribution to be delivered to the tumor bed
and to the surrounding normal tissues. This study aims to develop a treatment planning system (TPS) for IORT based on pre-treatment CT images
and pre-calculated Monte Carlo dose distributions. The TPS should allow
the selection of the appropriate energy, applicator diameter and beveling angle, position and incidence angle of the beam. Based on this information thedose distribution should be calculated in a reasonably short time in order tobe used during the pre-treatment simulation phase as well as in the surgicalroom.
Materials: The TPS has been developed using the results of Monte Carlosimulations in water using EGSnrc/BEAMnrc for the Light Intra-Operative Accelerator (LIAC, SORDINA, Italy). A look-up table of dose distributions, one
for each energy, applicator diameter and beveling angle has been calculated
in water in a cartesian grid with a 2mm resolution and stored in a database.
The TPS allows to import the CT images in DICOM format from any scanner,delineate Regions of Interest (ROIs) and reconstruct a 3D model of the patient
and the accelerator to easily select the optimal ballistic. For each ROI an arbitrary electronic density can be assigned in order to mimic missing tissue (surgically removed) or protective devices, such as a protection discs. A fast ray
tracing algorithm has been applied in order to obtain the dose distribution in
the patient taking into account the in-homogeneities from CT images, basedon a appropriate calibration curve. The code has been written in Assembler
in order to reduce as much as possible the computational time as well as toimprove graphical performances. The software has been tested on two mathematical heterogeneous phantoms (with density in-homogeneities) and on
the CT images of 4 patients, one for each of the tumour sites/pathologies thatmost frequently require a IORT treatment (breasts, head and neck, prostateand sarcomas). Calculation times have been registered.
Results: Snapshots of the 3D graphical environment and of a calculated
distribution are shown in the figure below. The agreement between the dose
distribution calculated with Monte Carlo and the TPS is within 1% and 7% forhomogeneous and heterogeneous phantoms respectively. Calculation times
have always been less than 4 minutes.

S ATURDAY, M AY 7, 2011

S ATURDAY, M AY 7, 2011

P OSTER DISCUSSION

S 15

28 oral29 oral30 oralINTRAOPERATIVE ELECTRON RADIATION THERAPY PREPLANNING USING RADIANCE NEW FEATURES. THE NEED FOR
COMMON PROTOCOLS REVISITED
J. A. Santos Miranda1 , J. Pascau2 3 , R. Hernanz de Lucas4 , M. J. Rot San
Juan5 , A. Bouché6 , V. Morillo6 , R. M. Meirino7 , M. A. Infante Utrilla8 , A. P.
Milan Armengol9 , A. Soria9 , C. Illana10 , M. Valdivieso10 , M. Desco23 , F.
Calvo1
1
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Oncología,
Madrid, Spain
2
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Unidad deMedicina y Cirugía Experimental, Madrid, Spain
3
U NIVERSIDAD C ARLOS III DE M ADRID, Departamento de Ingeniería
Biomédica y Aeroespacial, Madrid, Spain
4
H OSPITAL R AMON Y C AJAL, Oncología, Madrid, Spain
5
H OSPITAL R AMON Y C AJAL, Radiofisica, Madrid, Spain
6
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Oncología,
Castelló de la Plana, Spain
7
C LINICA L A L UZ, Oncología, Madrid, Spain
8
C LINICA L A L UZ, Radiofisica, Madrid, Spain
9
T ÉCNICAS R ADIOFÍSICAS , S.L., Zaragoza, Spain
10
GMV A EROSPACE AND D EFENCE , S.A.U., Tres Cantos, Spain

VIRTUAL PLANNING FOR IEORT: RADIANCE MAIN FEATURES AND
RECENT IMPROVEMENTS
J. Pascau12 , J. A. Santos Miranda3 , C. González-San Segundo3 , F.
Carlos4 , A. Ramos5 , R. M. Meirino6 , F. Calvo3 , M. Desco1
1
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Unidad deMedicina y Cirugía Experimental, Madrid, Spain
2
U NIVERSIDAD C ARLOS III DE M ADRID, Departamento de Ingeniería
Biomédica y Aeroespacial, Madrid, Spain
3
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Oncología,
Madrid, Spain
4
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Oncología ,Castelló de la Plana, Spain
5
H OSPITAL U NIVERSITARIO R AMÓN Y C AJAL, Oncología, Madrid, Spain
6
C LINICA L A L UZ, Oncología, Madrid, Spain

AN INTRA-OPERATIVE RADIOTHERAPY ACCELERATOR COMMISSIONING TOOL BASED ON MONTE CARLO SIMULATION
G. Iaccarino1 , M. D’Andrea1 , M. Grusio2 , L. Bellesi1 , A. Soriani1 , G. Felici2 ,A. Ciccotelli2 , M. Benassi1 , L. Strigari1
1
N ATIONAL C ANCER I NSTITUTE R EGINA E LENA, Laboratory of Medical
Physics and Expert Systems, Rome, Italy
2
S ORDINA S. P.A., Saonara (PD), Italy

Purpose: Intraoperative Electron External Radiotherapy (IOERT) is a challenging treatment since it involves radiation therapy and surgery. Recent introduction of radiance simulation and planning system offers a new tool for theradiation oncologist (RO), allowing treatment simulation in several steps: segmentation, applicator positioning using CT and 3D rendering and parameterselection (applicator diameter, bevel angle and electron beam energy) by optimizing the Dose Volume Histograms (DVHs) on the regions. Recently, newfeatures have been included: a pencil beam calculation algorithm is available,
and bolus or protections can be drawn and their electronic density selected,
modifying the calculated dose. Experienced users have tested these new
possibilities reporting a better pre-planning of the procedure. The purpose ofthis work is to evaluate the current version of the tool, including these newplanning advances, in clinical cases by ROs that have not participated in radiance development till now.
Materials: 5 cases, with a CT previous to IEORT, were used for the evaluation. They included the following cancer locations: breast, rectal, ovary
relapse, pancreas, and Ewing sarcoma. All were simulated by different ROs
from three hospitals: the specialist with longest experience on IOERT procedures was used as a reference. The other physicians had no experienceon the use of radiance. Clinical history of the patient was provided with everycase. Each evaluator segmented the regions of interest, placed the applicatorand selected the treatment parameters in order to optimize the dose coverage on the target volume. Accordance between users was evaluated for thefollowing aspects: segmentation regions, treatment parameters, applicator
position and use of bolus and protections.
Results: High agreement was found in the simplest cases: breast and rectal
cancer: All ORs performed similar tumor and high risk areas segmentation,
and applicator parameters were equivalent in both cases. However, the remaining locations showed some discordance in the results: different surgicalaccess, bolus, high risk area definition and applicator location were foundamong the users.

Purpose: The RADIANCE (GMV, Spain) treatment planning system allows
IOERT patient-specific virtual surgical simulation and electron beam interaction. The current state of the project, including details on its clinical use, ispresented in this work.
Materials: Development of the system started as an industrial and academic
initiative in 2007 (GMV, Hospital General Universitario "Gregorio Mara andHospital Provincial de Castellpain). The tool allows planning IOERT interventions from CT studies of a patient. Other modalities can also be used
as complementary information. The planning process is as follows: 1) segmentation, user can select several regions to be considered organs at risk,
structures to be removed during surgery, high relapse risk areas, bolus orprotections; 2) simulation of patient positioning during surgery, accomplishedby rotating the CT image, allowing virtual definition of the surgical frame; 3)
selection of applicator parameters (diameter and bevel angle), and position;4) selection of treatment energy with calculation of Dose Volume Histograms(DVHs) for the different regions. The DVHs are generated from dose distributions measured on a water phantom, but can also be estimated by meansof a specific implementation of the Pencil Beam (PB) algorithm. This allows
estimating the real interaction between radiation beam and patient anatomy
or other objects. The pre-planning process includes interaction with the surgeons, who can indicate the expected surgical access and high risk areas inorder to incorporate this information.
Results: 41 patients have been evaluated, 33 retrospective and 8 prospective. The tumor types were: rectal and colon cancer (19), recurrences (6),sarcomas (8), breast cancer (5), pancreatic cancer (2) and chordoma (1).
Clinical testing has proved feasibility of a) pre-tailoring IOERT target definition in agreement with surgical and radiotherapeutical individualized criteria;b) intra-surgically guided selection and optimization of pre-planning estimatedparameters; c) post-planning definitive registration of the actual performed
procedure for documentation and record. The system has proved the ability
to integrate both radiotherapists and surgeons in the simulation and planning
process. The stability of the current development has allowed the installationand clinical use of radiance systems in four hospitals in Spain (Hospital General Universitario "Gregorio Mara, Clca La Luz, Hospital Provincial de Castellospital Ramajal). These centers are now collaborating in establishing new
protocols for IOERT that involve simulation and planning with the presented
tool.

Purpose: The commissioning of a IORT accelerator requires measurementsof depth dose, off-axis dose profiles and output factors for each energy andapplicator type. In particular the most recent model of the Light Intraoperative
ACcelerator (LIAC, SORDINA, Italy) has 4 energies (6, 8, 10 and 12 MeV) anda set of 28 applicators: 7 different diameters (3, 4, 5, 6, 7, 8 and 10 cm) X 4
different beveling angles (0◦ , 15◦ , 30◦ and 45◦ ). This means that the LIAC
commissioning needs more than one hundred measurements. Aim of thiswork is to develop a tool that helps the medical physicist in the commissioningof a IORT accelerator generating all the necessary data from a minimal set ofbasic measurements.
Materials: The tool has been developed in MatlabTM . It allows to store theexperimental percentage depth doses (PDDs) and off-axis profiles (OAPs)of two mandatory irradiation setups: LIAC with the flat 10 cm applicator andwithout any applicator. Starting from these data the tool calculates the dose
distributions in water for all the other applicators (both flat and bevelled). Thisis done using a database that had been previously created, which contains
the pre-calculated simulated dose distributions of all the applicators for monoenergetic energies ranging from 3.5 to 15.0 MeV with a step of 0.1 MeV.
The Monte Carlo codes BEAMnrc and EGSnrc were used to simulate theparticle transport in the LIAC geometry and to calculate the dose in water, respectively. The simulated annealing optimization algorithm was used to findthe weights of the monoenergetic PDDs that minimize the objective function
given by the sum of the squared differences between calculated and measured PDDs at each depth. The weights obtained from the optimization areused as input to calculate the 3D distributions and the output factors of theother flat/beveled applicators.
Results: The figure shows a step of the optimization process to find the spectrum for a nominal energy of 12 MeV. The software has been tested in thecommissioning of 3 LIACs. For all energies and applicators, the differences
between calculated and experimental depth doses are almost everywhere
less than 2% (about 3% only around the depth of practical range). Likewise,
the distance to agreement between the calculated and experimental off-axis
profiles are almost everywhere less than 1 mm. The differences between calculated and experimental output factors are less than 2%, with the exceptionof the smallest applicator (3 cm diameter) for which the difference is between
3 and 4%.

Conclusions: The software has been proven to be easy to use in handling
patient images, in delineating ROIs, in selecting the optimal beam ballistic andin evaluating the expected dose distributions. Calculation times are consistent
with routine use in the surgical room.

Conclusions: The software is easy to use and useful to check the experimental data from various LIAC, supporting the medical physicist in the commissioning phase reducing the workload and improving accuracy. Noteworthy
the dose distribution generated by this tool can be used as input (i.e. look-up
table) for a treatment planning system.
Conclusions: The results show that although the inclusion of new features
allows better planning of the IOERT procedure, this does not imply coincidence between users if they do not have previous experience with the system. It is still necessary to define common clinical protocols for the preplanning process with this new tool, in order to improve the agreement between clinical users. Project funded by Spanish Ministry of Science and Innovation (PI09/90568, PSE-300000-2009-5, IPT-300000-2010-3, Comunidad
de Madrid ARTEMIS S2009/DPI-1802 and FEDER founds).

Conclusions: This virtual pre-intra-post planning system reproduces the realradiosurgical process involved in IOERT, and includes now real dose modeling. Predictability of IOERT treatment decision process (including surgicaland radiation treatment outcomes) is possible with this version of radiance.
The multi-site collaboration will result in new guidelines for IOERT planningwith this new approach. Project funded by Spanish Ministry of Science and Innovation (PI09/90568, PSE-300000-2009-5, IPT-300000-2010-3, Comunidad
de Madrid ARTEMIS S2009/DPI-1802 and FEDER founds).

S 16

P OSTER DISCUSSION

31 oralMONTE CARLO STUDY OF “HARD” AND “SOFT-DOCKING”
ELECTRON BEAM APPLICATOR SYSTEMS FOR A NEW MOBILEINTRAOPERATIVE ACCELERATOR
A. Wysocka-Rabin1 , P. Adrich1

S ATURDAY, M AY 7, 2011
Results: We found that in 35 treatments the mean target dose differed morethan 5% from the prescription dose, while using Nemo X’s normalization this
could have been reduced to 2 treatments (Fig. 1). The V107% analysis showsthat the over-dosage areas were usually quite large (<V107%> = 35%) while
using Nemo X this drastically reduces to 2%.

T HE A NDRZEJ S OLTAN I NSTITUTE FOR N UCLEAR S TUDIES, Department ofaccelerator physics, Otwock-Swierk, Poland

32 oralAN AUTOMATIC NORMALIZATION TOOL FOR OPTIMIZED IORTTREATMENTS OF THE BREAST WITH ELECTRON BEAMS
S. Agostinelli1 , G. Taccini1
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, S.C. Fisica Medica,
Genova, Italy

Purpose: In IORT treatments of the breast with electron beams the dosenormalization has to take into account the depth of the tumorectomy (target)
site, the entrance dose and the clinical range of the beam. Once chosen themost appropriate beam energy, a good trade-off between target coverage,
entrance dose and tissue over-dosage is to normalize the dose to the R90%
(clinical) range. Quite often however, the target is shallower than the beam’s
range, so normalization to R90% can lead to unnecessary large over-dosage
areas. In this work we analyze an automatic tool for dose normalization basedon the DVH of the target.
Materials: 66 patients which underwent IORT treatment of the breast were
investigated. Al the treatments were performed with a LIAC (Sordina, Italy)
mobile accelerator producing electrons with nominal energy 4, 6, 8 and 10
MeV collimated through Plexiglas circular applicators. For each treatment
an experienced medical physicist provided selection of the beam energy andmonitor units (MU) calculation based on the applicator size, daily output of
the beam and depth of the target. For each treatment the surgeon measured with a needle ruler the target depth at four different positions; based onthese measurements the maximum and minimum depths of the target wererecorded. The selected beams were: 8, 10, 6 and 4 MeV in 47%, 43%, 8%
and 2% of the treatments respectively. Applicator size was: 5, 6 and 4 cm in
56%, 26% and 18% of the treatments respectively.We developed an extension tool of our Nemo X (www.agolabs.com1 ) software application for IORT
treatments. The tool provides MU calculation for IORT beams based on theapplicator-specific dose output and PDD data. Dose normalization can bemade to a specific range (e.g. R90%) or to DVH related quantities (median,mean and V95%). The DVH is computed by modelling the target as a cylinder extending from beam entry to the maximum depth of the target. Nemo X
provides also a "best guess" of the dose as measured by an in-vivo dosimeterput at the distal end of the target based on the analysis of the PDD in the target depth range.Using Nemo X we computed the mean target dose and the
V107% according to the real treatment normalization and in the situation inwhich the dose is normalized so to cover the 95% of the target with the 95%of the prescribed dose (V95% = D95%).
1 http://www.agolabs.com/

34 oralINTRAOPERATIVE ELECTRON BEAM RADIOTHERAPY IN THE
MANAGEMENT OF RECURRENT OVARIAN MALIGNANCIES
B. Barney1 , I. Petersen1 , M. Haddock1
1

1

Purpose: Intra Operative Radiation Therapy (IORT) enables delivery of ahigh dose of ionising radiation to cancer tissue as a single fraction, following tumor ablation during oncological surgery. Specially constructed highlymobile electron accelerators have been developed to facilitate IORT procedures. There are two different methods of docking the applicator, which thesurgeon places in the patient , to the accelerator head. With "hard" docking
the applicator is attached rigidly to the accelerator head, while with the "soft"
docking there is no physical contact between the applicator and the accelerator head. The aim of this work was to study the effects of different docking
systems on such critical beam properties as flatness, X-ray contamination,and the amount of dose delivered outside the treatment field. Based on thesefindings, a docking method will be chosen for the new mobile electron accelerator.
Materials: The Monte Carlo code, BEAMnrc/EGSnrc, was used to build andtest two docking system models for circular metalic applicators. The designof scattering and flattening foils and collimator system was identical for bothmodels.
Results: Simulations were performed for initially monoenergetic electron
beams and SSD equal to 60 cm. Simulations covered beam energy range
from 4 to 12 MeV. Calculations were repeated for circular applicators withdiameters ranging from 4 10 cm for different materials of applicators: steel
and brass. However, as elongated field shapes are often desirable for IORT
procedures, we also studied potential applicators with non circular shape andmaximum length of 12 cm.
Conclusions: Two different docking systems of applicators for a new electron
accelerator for IORT have been designed, verified and optimized based onMonte Carlo calculations. The final selection of the docking system for the
new accelerator will be made by design engineers and a prototype model
will be built and tested in the laboratory. This work was funded by the Polish
Ministry of Science and Higher Education and the EU in frame of Operational
Programme Innovative Economy, project no. POIG 1.1-21

S ATURDAY, M AY 7, 2011

Conclusions: We have developed a tool for automatic normalization of IORT
electron beams based on the target’s DVH. We have shown that this tool can
improve the target dose conformity in terms of mean target dose and overdosage.

Poster Rapporteur Session: GI / GU Tumors I
33 oralAGGRESSIVE LOCAL TREATMENT CONTAINING INTRAOPERATIVE RADIATION THERAPY (IORT) FOR PATIENTS WITH ISOLATEDLOCAL RECURRENCES OF PANCREATIC CANCER
F. Roeder1 2 , C. Timke2 , M. Uhl1 , G. Habl1 , U. Krautter1 , F. Hensley1 , M.
Buechler3 , J. Werner3 , J. Debus1 2 , P. Huber1 2 , R. Krempien4
1
U NIVERSITY OF H EIDELBERG, Department of Radiation Oncology,
Heidelberg, Germany
2
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Radiation
Oncology, Heidelberg, Germany
3
U NIVERSITY OF H EIDELBERG, Department of Surgery, Heidelberg,
Germany
4
A KADEMISCHES LK DER U NIVERSITÄT C HARITÉ, Department of Radiation
Oncology, Berlin, Germany
Purpose: To evaluate the use of intraoperative radiation therapy (IORT) in
the multimodality treatment of patients with isolated local recurrences of pancreatic cancer.
Materials: We retrospectively analyzed 36 patients with isolated local recurrences of pancreatic cancer who have been treated with a combination ofsurgery, IORT and EBRT. Median time from initial treatment to recurrence
was 20 months. All patients were surgically explored. In 18 patients a grosstotal resection was achieved, whereas the other half received only debulking
or no resection at all. All patients received IORT with a median dose of 15
Gy. Additional EBRT was applied to 31 patients with a median dose of 45 Gy,
combined with concurrent, mainly gemcitabine-based chemotherapy.
Results: Median follow-up in surviving patients was 23 months. Local progression was found in 6 patients after a median time of 17 months, resulting
in estimated 1- and 2-year local control rates of 91% and 67%, respectively.
Distant failure was observed in 23 patients, mainly in liver or peritoneal space.
The median estimated progression-free survival was 9 months with 1- and 2year rates of 40% and 26%, respectively. We found an encouraging estimatedmedian overall survival of 19 months, transferring into 1- and 2-year rates of
66% and 45%. Notably 6 of 36 patients (17%) lived for more than 3 years. Severe postoperative complications were found in 3 and chemoradiation-related
grade III toxicity in 6 patients. No severe IORT related toxicity was observed.
Conclusions: Combination of surgery, IORT and EBRT in patients with isolated local recurrences of pancreatic cancer resulted in encouraging local
control and overall survival in our cohort with acceptable toxicity. Our approach seems to be superior to palliative chemotherapy or chemoradiation
alone and should be further investigated in a prospective setting specificallyaddressing isolated local recurrences of pancreatic cancer.

M AYO C LINIC, Radiation Oncology, Rochester, USA

Purpose: Intraoperative electron beam radiotherapy (IOERT) has routinely
been used at our institution for treatment of localized or recurrent gynecologic malignancies when surgical margins are close or positive. Although
peritoneal relapse is the most common pattern of failure in ovarian cancer,
a subset of patients will experience local relapse without peritoneal relapse.
Here we present the clinical outcomes and toxicity data for patients with recurrent ovarian malignancies who received IOERT at the Mayo Clinic as acomponent of their cancer therapy.
Materials: From November 1987 to January 2009, 21 patients with recurrent ovarian malignancies received IOERT. All patients underwent maximum
surgical resection prior to IOERT. Only one patient (5%) had gross residual tumor prior to receiving IOERT. The median IOERT dose was 1250 cGy (range
1000-2250). All but 4 patients (81%) received external beam radiotherapy(EBRT) immediately before or after surgery; 11 (65%) before surgery, and 6(35%) afterwards. The median EBRT dose was 5000 cGy (range 2000-5430).
All patients were followed from the date of IOERT for clinical outcomes including toxicity.
Results: The median follow-up time for surviving patients was 5 years (range0-15). The most common histology was high-grade adenocarcinoma. The
median pre-operative tumor size was 5.0 cm (range 2.2-15.3). Median survival was 29 months, and the 3- and 5-year Kaplan-Meier estimates of survival were 47 and 41%, respectively. Central relapse within the IOERT field
was observed in 2 patients (10%) and 3- and 5-year freedom from central
relapse rates were 94 and 81%, respectively. Local relapse in the EBRT
field was observed in 5 patients (24%) with 3- and 5-year freedom from local relapse rates of 75 and 64%, respectively. All local relapses occurred inpatients who had margin positive surgical excisions. Distant relapse was observed in 9 patients (43%) with 3- and 5-year freedom from distant relapse
rates of 46% and 37%, respectively. Four patients (19%) experienced Grade
3 or higher toxicities, the majority of which were attributed to surgery, EBRT,
and/or chemotherapy. Three patients developed small bowel obstructions,and 1 patient developed an abscess requiring hospitalization. Three patients
experienced Grade 1 or 2 peripheral neuropathy related to IOERT.
Conclusions: Combined modality therapy with EBRT, surgery, and IOERT isa reasonable local treatment for recurrent ovarian cancer. The rates of in-field
failure are low, and toxicities are acceptable. Using this approach, durable
disease control is achievable in patients who experience localized relapse ofovarian cancer.
35 oralINTRAOPERATIVE IRRADIATION IN RECURRENT PELVIC CANCER:UPDATE, TUMOR FRAGMENTATION AND LONG-TERM RESULTS
J. A. Blanco1 , A. Alvarez1 , M. A. Lozano1 , J. L. Garcia-Sabrido2 , L.
Gonzalez-Bayon2 , E. Alvarez3 , R. Herranz1 , F. Calvo1
1
H OSPITAL G REGORIO M ARAÑÓN, Department of Radiation Oncology,
Madrid, Spain
2
H OSPITAL G REGORIO M ARAÑÓN, 1st Division of General Surgery, Madrid,
Spain
3
H OSPITAL G REGORIO M ARAÑÓN, 1Department of Oncology-Pathology,
Division of Clinical Cancer Epidemiology, Madrid, Spain
Purpose: To analyze retrospectively, in terms of feasibility, local control, tumor fragmentation and overall survival, the results of extensive pelvic surgery
plus intraoperative electron irradiation as rescue treatment in localized pelvic
cancer recurrence.
Materials: From 1995 to 2009, 56 patients (p) were treated. Primary sites
included colo-rectal (54%), gynecologic (39%) and other origin (7%). 35 p
were female (62%). Age range from 21 to 84 (median 56). Dominant histology
was adenocarcinoma (73%). Topography of recurrence was: centro-pelvic(57%), presacral (23%) and lateral walls (20%). Size of recurrence range
from 0.8 to 13 cm (median 3.5 cm) and 28% were up to 5 cm.
Results: Patients underwent sacro-pelvic resection in 32%, multiorgan in
34% and atypical debulking or tumor exposures in 34%. IOERT dose ranged
from 750 cGy to 1500 cGy (median 1250 cGy). Additional RT was given to
25% and CT in 37%. Surgical resection margins were positive in 39% of thespecimens. With a median follow-up time of 34 months, the overall survival
was 18% and the cause-specific survival was 26%. Positive surgical margins
was an influencing factor on overall survival (16% vs 31% p=0.02). The local
control rate was 52% with a trend towards negative surgical margins (55%vs 47% p>0.05). Adyuvant treatment with RT and/or CT had no impact on
outcome in our series. 14 patients are still alive with no evidence of disease(25%).
Conclusions: The association of extensive pelvic surgery and IOERT as
rescue treatment for localized pelvic cancer recurrence is a feasible and tolerable procedure with high local control rates and long-term survivors. ThisP OSTER DISCUSSION

S 17

is a promising approach for patients with unprofitable treatment options. Preliminary results on tumor fragmentation will be added.
36 oralINTRAOPERATIVE RADIOTHERAPY FOR LOCALLY ADVANCEDPROSTATE CANCER: TREATMENT TECHNIQUE AND PRELIMINARY OUTCOMES.
A. Vavassori1 , B. A. Jereczek-Fossa12 , F. Cattani3 , C. Fodor1 , F.
Gherardi12 , D. Zerini1 , A. Cecconi1 , R. Cambria3 , E. Rondi3 , C. Garibaldi3 ,R. Lazzari1 , O. De Cobelli42 , G. Musi4 , B. Rocco4 , F. Mazzoleni4 , R.
Orecchia12
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Radiotherapy, Milan,
Italy
2
U NIVERSITY OF M ILAN, Milan, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Medical Physics, Milan,
Italy
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Urology, Milan, Italy
Purpose: To present the technique adopted for intraoperative radiotherapy(IORT) for locally advanced prostate cancer and preliminary outcomes
Materials: Between June 2005 and December 2010 50 consecutive patients(pts) with non-metastatic intermediate-risk or locally advanced prostate cancer were treated with IORT before prostatectomy as part of their surgical procedure.Median age was 65 years. The median iPSA was 14 ng/ml and the
median bioptic Gleason Score was 7.According to NCCN 2010, risk group
distribution was as follows: intermediate risk 4 pts (8%), high risk 43 pts(86%) and very high risk 3 pts (6%). A total of 21 pts (42 %) were treated withneoadjuvant hormonal therapy.Immediately before IORT prostate dimensions
and rectum depth were measured with intraoperative ultrasound in order toselect properly the electron beam energy and the applicator size and to estimate the doses to target and organs at risk.IORT was delivered by a mobile
linear accelerator in the operating room, using 8-10 MeV electron energies
and 5-7 cm diameter applicators. The prescribed dose was 12 Gy at the 90%
isodose.According to the pathological findings further adjuvant radio or hormonal therapy could be administered: three months later, postoperative external beam radiotherapy (EBRT) was prescribed to the prostatic bed alone
and whole pelvis in case of pT3-4 pN0 and pN1, respectively.
Results: According to the Memorial Sloan Kettering Cancer Center nomograms, the mean preoperative probability of organ-confined disease, extracapsular disease and lymph node involvement were 15%, 45% and 22% respectively.Postoperative histological findings were as follows: median GS 8,
pT2 8 pts, pT3 37 pts, pT4 5 pts, pN0 27 pts, pN1 23 pts.One patient diedfor postoperative pulmonary embolism.Organ confined disease with negative surgical margins (R0) was diagnosed in 4 pts and no further radiation
treatment was prescribed.Adjuvant pelvic and prostatic bed EBRT were administered in 21 and 19 pts, respectively.No patients had major acute rectal
toxicity. Twenty-three pts had G1-G2 urinary acute toxicity and 2 pts had
G3 acute urinary toxicity (jatrogenic monolateral uretheral stricture and acuteurinary retention, respectively). No increased risk of urinary incontinence
was recorded.After a median follow up of 31 months 7 pts had evidence ofbiochemical failure, 2 of them with clinical failure evidence (lymph node andbone metastasis).
Conclusions: IORT delivered before prostatectomy appeared a feasible andsafe approach for locally advanced prostate cancer, but longer follow-up isneeded to evaluate late toxicity and clinical control.Further investigation is
warranted in order to identify the patients that benefit most from this treatment
modality.
37 oralINTRA-OPERATIVE RADIOTHERAPY FOR LOCALLY ADVANCEDPROSTATE CANCER: TECHNICAL AND CLINICAL ASPECTS
M. Krengli1 , R. Tarabuzzi2 , G. Apicella1 , G. Loi3 , G. Marchioro2 , D. Beldì1 ,E. Mones3 , A. Volpe2 , L. Turri1 , C. Terrone2
1
R ADIOTHERAPY U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ,Novara, Italy
2
U ROLOGY U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Novara, Italy
3
M EDICAL P HYSICS , U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ,Novara, Italy
Purpose: To analyze the technical and clinical aspects of intra-operative radiotherapy (IORT) in patients with locally advanced prostate cancer and candidates for radical prostatectomy.
Materials: 54 patients aged from 56 to 75 years (median 67.2) with locallyadvanced prostate cancer were enrolled in this prospective study. Patients
had no evidence of lymph node or distant metastases, probability of organconfined disease < 25%, and risk of lymph node involvement < 15% according
to the MSKCC nomogram. Median PSA at diagnosis was 15.32 ng/ml (range
2.03-63.90 ng/ml) and median Gleason score (GS) at biopsy was 8 (range4-10). IORT was delivered by a dedicated linear accelerator after exposureof the prostate with beveled collimator using electrons of 9-12 MeV to a total
dose of 10-12 Gy (median 12 Gy). Rectal dose was measured "in vivo" by

S 18

P OSTER DISCUSSION

radio-chromic films placed on a rectal probe. IORT was followed by completion of radical prostatectomy and regional lymph node dissection. All caseswith extracapsular extension and/or positive margins received postoperative
radiotherapy. Patients with pT3-4 disease or positive nodes received also
adjuvant hormone therapy. All patients had minimum 6 months follow-up.
Results: IORT procedure lasted 31 minutes on average (range 15-45 minutes). No major intra- or post-operative complications occurred. Median dose
detected by radio-chromic films was 4.2 Gy (range 0.1-11.3 Gy) to the anterior rectal wall. Pathological stage was: 18 pT2, 33 pT3, 3 pT4. Median GS
on pathology specimen was 9 (range 6-10). Positive surgical margins were
found in 29/54 (53.7%) patients and positive lymph nodes in 13/54 (24.1%).
Median post-operative PSA was 0.04 ng/ml (range 0.00-5.05 ng/ml). Postoperative radiotherapy was prescribed to surgical bed about 3 months after
surgery, using 3-D conformal technique (4-6 beams or dynamic arcs) to a
total dose of 46-50 Gy (2 Gy/fx). Thirty four patients received adjuvant hormone therapy. In the 47/54 patients who underwent postoperative externalbeam radiotherapy, 2 experienced grade 3 acute toxicity, 1 rectal and 1 urinary. Grade 2 late toxicity was observed in 3/47 cases: 2 cystitis and 1 rectal
bleeding. No grade 3-4 late toxicity was observed. At present, all patients arealive with median follow-up of 24 months (range 6-46 months) and median
PSA value of 0.04 ng/ml (range 0.00-432.00 ng/ml). Eight out of 54 patients(14.8%) experienced biochemical failure with median time to progression of
27 months (range 6-44 months).
Conclusions: IORT during radical prostatectomy is a feasible procedure andallows to safely deliver postoperative external beam radiotherapy to the tumor
bed without relevant rectal toxicity. Longer follow-up is needed to assesslong-term outcome including late side effects and biochemical relapse-freeand overall survival.

Poster Rapporteur Session: GI / GU Tumours II
38 oralINTRAOPERATIVE ELECTRON PELVIC BOOST DURING LAPAROSCOPIC RADICAL SURGERY FOR RECTAL CANCER:PRELIMINARY RESULTS.
J. Serrano1 , F. Calvo1 , M. Gomez-Espí1 , F. Marcos1 , M. Rodriguez1 , B.
Diaz-Zorita1 , E. Del Valle1 , E. Alvarez1 , R. Herranz1
1
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Madrid, Spain
Purpose: To describe the technical feasibility and preliminary outcomes combining laparoscopic radical resective surgery and intraoperative electrons
boost in the model of neoadjuvant combined modality treatment for rectal
cancer patients (p).
Materials: From 07/06 to 11/10, 43 p were included into the program to implement local therapy for locally advanced rectal cancer combining neoadjuvant
fluoropirimidine-based chemoradiation with laparoscopic radical resection integrating an IOERT boost to the tumor bed region (posterior pelvic cavity). P
age ranged from 32-86 years old (median 63). Endorectal ultrasound / MRclinical stages were cT2N+ (12%), cT3N+ (58%) and cT4N0/+ (28%) and.
Distance to the anal margin were: 1-5 cm (42%), 6-10 cm (53%) and >10
cm (5%). Previous abdominal surgery was present in 15 p (35%). The ASA
score was II en 28 p (68%) and III in 6 p (15%).
Results: All patients were resected: 16 abdomino-perineal and 27 ultra-low
or low anterior resection procedures (63% preservative surgery). Protective
colostomy was used in 16 p (37%). IOERT was administered with applicators from 5 to 8 cm (5-6 cm 93%), electron energies ranged from 6 to 15
MeV (12-15 Mev 81%) and doses delivered were from 1000 to 1500 cGy(>1000 cGy 54%). No technical limitations were observed due to the modified surgical approach. Only 11 p (26%) needed blood transfusions along thesurgical process time (7% >2 units). Median time of the surgical procedure including transportation for IOERT component was 265 minutes (IR: 220-345).
Postoperative complications were observed in 16 p (37%): scar infection (5),seroma (2), dehiscence (3), urinary obstruction (2), perineal pain (1), anastomotic bleeding (1) and fistula (1). Complete or quasi-complete mesorectal
excision was achieved in 84% of cases. Radial margin was free from tumor
involvement in 98% specimens and distal margins ranged from 2 to 65 mm(mean 27 mm). The median time to hospital discharge was 8 days (ranged
from 3 to 40 days).
Conclusions: The integration of IOERT boost during laparoscopic radical
surgery for locally advanced rectal cancer is feasible and not limited by thesurgical technical changes and adaptations. IOERT may improve further theefficient progress of laparoscopic cancer surgery.
39 oralPRESACRAL EVOLUTIVE EVENTS AFTER POST-NEOADJUVANTINTRAOPERATIVE PRESACRAL RADIATION BOOST FOR RECTALCANCER.
F. Calvo1 , J. Serrano1 , M. A. Lozano1 , M. Gomez-Espí1 , S. Botella1 , M.
Muñoz1 , E. Del Valle1 , J. L. Garcia-Sabrido1 , E. Alvarez1 , R. Herranz1
1
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Madrid, Spain

S ATURDAY, M AY 7, 2011

Purpose: To analyze the long-term clinico-radiological changes observed in
the IOERT boosted area in locally advanced rectal cancer patients following
neoadjuvant chemoradiation and radical surgery.
Materials: From 12/94 to 08/06, 241 patients with locally advanced rectal
cancer stages cT3 (87%), cT4 (9%) and/or cN+ (60%) received an intraoperative presacral electron boost at the time of surgical resection. Doses
were 1000 cGy (23%), 1250 cGy (75%) or 1500 cGy (2%). Electron energies ranged from 6 Mev to 15 Mev (most frequently selected were 12 and
15 Mev, 30 and 37%). Applicator diameter used ranged from 5 to 9 cm (5/6
cm, 62%). Beveled end of 45 in 95% of procedures. Preoperative external
pelvic radiation consisted in 4500-5040 cGy concurrent to fluoropirimidine
based chemotherapy. Sphincter preserving surgery was performed in 64% ofcases.
Results: With a median follow-up time of 63 months, 5/10-years overall,disease-free and local relapse-free survival were 70%/54%, 69%/65%, and90%/90%, respectively. The incidence of clinico-pathologically proven presacral recurrences (PR) was 3% (1 event as the only site of progression,
3 with synchronous distant metastasis and 3 with metachronous evidenceof dissemination). Non-presacral intrapelvic recurrences (NPIR) included 10
anastomotic (4%), 2 vaginal (1%), 1 urethral (0.5%) and 1 nodal (0.5%) relapses. Non-malignant presacral abnormalities (NMPA) were radiologicallydescribed in 21 patients (9%) along the follow-up period. Five and 10-years
overall survival among presacral events groups were 14% and 0% for PR patients, compared with 81% and 67% observed in NMPA cases (p=0.00). Features related to the development of these clinico-radiological presacral abnormalities were investigated (type of surgery, postoperative complications,applicator size, etc). The abdomino-perineal resection procedure and theuse of high electrons energies during the IOERT boost (≥15 Mev) were significantly associated with a higher risk to develop this presacral events in thelogistic regression model (RR=2.86 [1.24-6.62] and RR=2.74 [1.17-6.45].
Conclusions: Presacral radiological abnormalities can frequently appear after IOERT containing combined modality treatment (12%), but a large proportion of them could correspond to a non-malignant nature (21/28 cases, 75%).
In our cohort of patients, the long-term outcome data confirm the validity ofthis observation (10-years overall survival 67% vs. 0%). The combinationof aggressive procedures over the presacral area may trigger this observation. The potential relationship between NMPA and presacral IOERT is still
unclear.
40 oralPROGNOSTIC ROLE OF CURATIVE RESECTION PLUS IORT IN
LOCAL RECURRENCE OF RECTO-SIGMOID COLON AND RECTALCANCER
A. Ciabattoni1 , M. A. Mirri1 , L. M. Cosentino2 , A. Belardi2 , S. Mancini2 , A.
Siniscakchi1 , F. Fabretti1 , G. Grassi2
1
A ZIENDA C OMPLESSO O SPEDALIERO S AN F ILIPPO N ERI R OMA, UOC
Radioterapia, roma, Italy
2
A ZIENDA C OMPLESSO O SPEDALIERO S AN F ILIPPO N ERI R OMA, UO
Chirurgia, roma, Italy
Purpose: About 50% of the local recurrences of recto-sigmoid colon and rectal cancer (CRC) represents the only localization of disease. Radical surgery
is achievable only in one third of the patients. In recent years, encouraging results of intraoperative radiotherapy (IORT) on CRC have been reported. The
aim of this study is to compare the long-term outcomes of combined modality therapies with or without IORT in patients affected by local recurrence of
CRC.
Materials: Sixty one patients had surgical resection for local recurrence of
CCR from June 1998 to April 2010 in Surgical Department of S. Filippo Neri
Hospital in Rome. All analyzed patients had primary CRC. Thirty six of themwere male and twenty five female. Median age was 68.6 years, (range 3384). Out of sixty one, 13 patients underwent neoadjuvant chemoradiation,with continuous course 45 Gy/25 fractions on the whole pelvis, followed by 5,4
Gy/3 fractions on the gross disease and concomitant 5-FU infusion. Fifteen
patients were treated with post-operative radio-chemotherapy. IORT boost
was employed in all of the 13 patients at a dose of 10 to 12 Gy to the tumor
bed after marginal gross total resection; exclusive IORT was employed infurther 3 patients. Overall IORT was performed in 16 patients. The IORT
was delivered in the operating scenario with a mobile Linac NOVAC7, using
6 MeV electrons on the anatomic site of disease.
Results: In the resected patients, the mean time to local recurrence was26,3 months. The most frequent recorded features for local recurrence were:male gender, previous sphincter saving surgery and recto-sigmoid colon localization, Dukes B stage, G2-3 grading, no lymphnodes involvement of
the primary. The majority of local recurrences were observed in anastomotic/perianastomotic site (57% of the cases). The median follow up was
36 months (range 1 to 180). Ten patients (16,3%) underwent only a derivative colostomy; 38 patients (74,5%) received an R0 resection and 35 patients(68,6%) had a sphincter saving procedure. No major acute or late complications were registered due to IORT boost. The symptoms-free interval was
twelve months (range 1 to 118). Twenty three patients (45%) are alive at the
moment, one patient died of ictus cerebri. The best results were obtained in
R0 patients, who showed a better overall survival (OS) versus the R1-2 (53,8

S 19

M ONDAY, M AY 9, 2011
and 37,2 months respectively). The overall pelvic control disease was 68,7%,
significantly better in IORT patients respect to the no-IORT (76,9% vs 65,7%,
p< 0,001). IORT caused a significant increase in OS both in R0 (94,8 vs 43,2months) and R1-2 resection (48 vs 33 months) and a longer symptoms-freeinterval only in R0 resection (49,7 vs 21,7 months without IORT).
Conclusions: Radical surgery represents the only curative treatment in locally recurrent CRC. An intensive follow-up is recommended in cases withadverse prognostic factors. Our experience confirms the role of IORT boost
on the OS and symptoms-free interval, but further studies are requested tovaluate the role of increased radiation dose on local control, quality of life andsurvival.

Monday, May 9, 2011
Teaching lecture
42 speaker
THE FUTURE OF BRACHYTHERAPY: WHAT ARE THE POTENTIALNEW RADIONUCLIDES?
D. Baltas1
1
K LINIKUM O FFENBACH G MB H, Offenbach am Main, Germany
Abstract not received.

41 oralLONG-TERM OUTCOMES WITH INTRAOPERATIVE RADIOTHERAPY AS A COMPONENT OF TREATMENT FOR ADVANCED UTERINESARCOMA
B. Barney1 , I. Petersen1 , S. Dowdy2 , J. Bakkum-Gamez2 , M. Haddock1
1
2

M AYO C LINIC, Radiation Oncology, Rochester, USA
M AYO C LINIC, Department of Gynaecologic Oncology , Rochester, USA

Purpose: To report our institutional experience with intraoperative radiotherapy (IORT) as a component of treatment for women with locally advanced orrecurrent uterine sarcoma.
Materials: From November 1990 to March 2010, 16 women with primary(N=4) or recurrent (N=12) uterine sarcoma confined to the pelvis and/or abdomen received IORT as part of a combined modality approach. For patientswith recurrent disease, the median time from original diagnosis to relapse
was 17 months (range, 4 to 273 months). Surgery consisted of a gross total resection (GTR) in 10 patients and a subtotal resection with microscopic
residual tumor in 6 patients. IORT was given in a single fraction with electrons(N=15) or with high-dose rate brachytherapy (N=1). The median IORT dose
was 12.5 Gy (range, 10 to 20 Gy). All patients also received perioperative
external beam radiotherapy (EBRT; median dose, 50.4 Gy; range, 20 to 62.5
Gy), including 6 patients with recurrent cancer who had previously received
pelvic irradiation at the time of first diagnosis. Six patients were treated withcytotoxic systemic therapy in the perioperative period as well. Median followup for surviving patients was 32 months (range, 0 to 203 months).
Results: The 3-year actuarial local control (within the EBRT field) was 92%,
and central control (within the IORT field) was 100%. There were no local
failures in any of the 6 patients with a subtotal resection. The 3-year freedom
from distant relapse was 42%, and the most common regions of distant failure
were other peritoneal sites and pulmonary. Median survival was 18 months,
and the 3-year Kaplan-Meier estimates of cause-specific and overall survival
were 56% and 50%, respectively (see figure). Only one patient experienced
Grade 3 or higher toxicity, suffering a pelvic fracture and avascular necrosisof the left femoral head approximately 8 years after primary treatment with
EBRT, surgery and IORT.

Conclusions: A combined modality approach with perioperative EBRT,
surgery, and IORT for advanced uterine sarcoma results in excellent local
disease control, even in patients with a less-than-gross total resection. Toxicity rates using this method are acceptable. The primary pattern of failure
is distant. Utilizing this approach, some patients were able to experiencelong-term freedom from disease recurrence.

S 20

S YMPOSIUM

Symposium
30 years of radiation oncology in Head & Neckcancer - What is the evidence that ‘we’ have created?
43 speaker
UPDATE OF META-ANALYSES AND EBM LEVEL 1 ON: FRACTIONATION
P. Blanchard1
1
I NSTITUT G USTAVE R OUSSY, Villejuif, France
Radiotherapy and surgery, alone or combined together or with chemotherapy, are the mainstay of treatment of head and neck cancers. The mostcommonly used schedule of radiotherapy is 2 Gy in a single fraction per day,
5 days a week, for 7 weeks. Despite these treatments, the prognosis of patients with head and neck squamous cell carcinomas (HNSCC) with locallyadvanced disease remains poor, with 5-year survival rates of 30-35%. In thepast twenty years, new radiotherapy regimens for the treatment of HNSCC
have been assessed. These regimens were designed to increase the doseintensity by delivering a higher total dose in the same time (hyperfractionatedradiotherapy), the same total dose in 5-6 weeks instead of 7 weeks (accelerated radiotherapy), or a smaller total dose given in 3-4 weeks (accelerated
radiotherapy with total dose reduction). Reducing the total treatment timeshould reduce the repopulation of tumour cells between fractions, resulting
in improved locoregional control and ultimately lead to an increase of overall
survival. In hyperfractionated regimens, two to three fractions are delivered
each day, with a reduced dose per fraction of around 1.1-1.2 Gy. The MARCH
meta-analysis showed that altered fractionation radiotherapy improved survival in patients with HNSCC, with an absolute benefit of 3.4% at 5 years(hazard ratio 0.92, 95% CI 0.860.97). Comparison of the different types ofaltered fractionation radiotherapy suggested that hyperfractionation provided
the greatest benefit and that this benefit tended to decrease with increasingage.
The reduction of the dose per fraction might reduce the risk of late toxicity, despite an increased total dose. Moreover, concomitant chemotherapy,
which improves survival when added to standard radiotherapy, has recently
been added to modified fractionation radiotherapy in clinical trials, to further
enhance therapy. This radiation technique has also been used in the postoperative setting, alone or combined with chemotherapy. On the other hand,the use of altered fractionated radiotherapy is associated with some increasein acute toxicity, mostly due to mucositis, and can add some practical constraints in radiotherapy departments that need to be balanced by substantial
benefits.
The different available fractionation regimens used in HNSCC, the role of altered fractionation radiotherapy in the context of concomitant chemotherapy,
or in the post-operative setting will be presented, using high quality randomized trials or meta-analyses as examples.
44 speaker
HYPOXIC MODIFICATION OF RADIOTHERAPY IN SQUAMOUS
CELL CARCINOMA OF THE HEAD AND NECK - A SYSTEMATIC
REVIEW AND META-ANALYSIS.
J. Overgaard1
1

A ARHUS U NIVERSITY H OSPITAL, Experimental Clinial Oncology, Aarhus C,
Denmark
Background: The importance of tumor hypoxia for the outcome of radiotherapy has been under investigation for decades. Numerous clinical trials modifying the hypoxic radioresistance in squamous cell carcinoma of the headand neck (HNSCC) have been conducted, but most have been inconclusive,
party due to a small number of patients in the individual trial. The present
meta-analysis was therefore performed utilizing the results from all clinical
trials addressing the specific question of hypoxic modification in HNSCC undergoing curative intended primary radiotherapy alone.
Methods: A survey of published and unpublished data identified 4805 patients with HNSCC treated in 32 randomized clinical trials, applying ), normobaric oxygen or carbogen breathing (5 trials) hyperbaric oxygen (HBO)(9); hypoxic radiosensitizers (17) and HBO and radiosensitizer (1). The trials
were analyzed with regard to the following endpoints: loco-regional control(32 trials), disease specific survival (30 trials), overall survival (29 trials), distant metastases (12 trials) and complications to radiotherapy (23 trials).
Results: Overall hypoxic modification of radiotherapy in head and neck cancer did result in a significant improved therapeutic benefit. This was mostdominant inobserved when using the direct endpoint of loco-regional control
with an odds ratio (OR) of 0.71, 95% cf.l. 0.63-0.80; p<0.001), but this wasalmost mirrored in the disease specific survival (OR: 0.73, 95% cf.l. 0.640.82; p<0.001), and to a lesser extent in the overall survival (OR: 0.87, 95%
cf.l. 0.77-0.98; p=0.03). The risk of distant metastases was not significantly
influenced although it appears to be less in the tumors treated with hypoxic
modification (OR: 0.87, 95% cf.l. 0.69-1.09; p=0.22), whereas the radiation

M ONDAY, M AY 9, 2011
related late complications were not influenced by the overall use of hypoxic
modifications (OR: 1.00, 95% cf.l. 0.82-1.23; p=0.96). The improvement
in loco-regional control was found to be independent of the type of hypoxic
modification. The trials have used different fractionation schedules, including large doses per fraction, which may result in relative more hypoxia and agreater benefit. However, analysis of HNSCC trials using conventional fractionation only, showed that the significant effect of hypoxic modification wasmaintained.
Conclusion: The meta-analysis thus demonstrate that there is level 1a evidence in favour of adding hypoxic modification to radiotherapy of squamouscell carcinomas of the head and neck.

M ONDAY, M AY 9, 2011

Abstract not received.

ESTRO-ESSO Joint Symposium: 30 years of radiation oncology in Rectal cancer - What is theevidence-base that ‘we’ have created?
46 speaker
EVIDENCE FROM META-ANALYSES (SHORT COURSE,
DIOCHEMOTHERAPY, ADJUVANT CHEMOTHERAPY)
D. Sebag-Montefiore

RA-

Abstract not received.

48 speaker
IMAGE REGISTRATION IN RADIOTHERAPY
G. Rizzo12 , E. Faggiano13
1
I STITUTO DI B IOIMMAGINI E F ISIOLOGIA M OLECOLARE , CNR, Segrate(Milano), Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Nuclear Medicine,
Milan, Italy
3
P OLITECNICO DI M ILANO U NIVERSITY, Department of Biomedical
Engineering, Milano, Italy
Image registration is widely recognized as an important tool in Radiotherapy(RT) to better configure RT plans and to evaluate RT efficacy. Image registration is more and more used to integrate multimodal information derived
from different imaging modalities, in order to better define structural and functional characteristics of the tumor and consequently to enhance delineationof Planning and Biological Target Volumes; furthermore registration of CT images acquired before and during RT is employed to estimate patient anatomical changes during time, thus allowing the study of deformation of organs
induced by RT as well as the introduction of Adaptive RT. However, the good
behavior of an image registration technique is strictly related to the specificclinical application and often to the specific image acquisition protocol: eachregistration approach presents relative merits and limitations that should beknown in order to really exploit the value of registration in RT. In this context
an important point is the availability of tools able to quantitatively assess thespatial accuracy of registration. The lesson introduces the principal registration techniques from the theoretical point of view. Specifically, the models of
spatial transformations (rigid and non rigid) as well as the main categories ofregistrations (feature-based, voxel-based) are comparatively discussed. The
main proposed approaches for non rigid deformation are reviewed. Finally,
the methodological framework to evaluate the performance of image registration in RT applications is presented and the main indices to quantitatively
assess registration accuracy are introduced.
49 speaker

47 speaker
COLORECTAL CANCER OUTCOME IMPROVEMENTS IN EUROPE:
POPULATION-BASED OUTCOME REGISTRATIONS WILL CONQUER THE WORLD
C. van de Velde1 , V. Valentini2
1
L EIDEN U NIVERSITY M EDICAL C ENTER, Department of Surgery, Leiden,
Netherlands
2
U NIVERSITA C ATTOLICA S.C., Department of Radiotherapy, Roma, Italy
In the last two decades, rectal cancer treatment improved considerably inEurope. Clinical trials played a crucial role in improving surgical techniques,(neo)adjuvant treatment schedules, imaging and pathology. However, there
is still a wide variation in outcome after rectal cancer. In most western healthcare systems, efforts are made to reduce hospital variation by focussing on
selective referral and encouraging patients to seek care in high-volume hospitals. On the other hand, the expertise for diagnosis and treatment of common
types of cancer should be preferably widespread and easily accessible for all
patients. As an alternative to volume-based referral, hospitals and surgeons
can improve their results by learning from their own outcome statistics andthose from colleagues treating a similar patient group. Several European surgical (colo)rectal audits have led to improvements with a greater impact thanany of the adjuvant therapies currently under study. However, differences
remain between European countries that cannot be easily explained. To generate the best care for colorectal cancer in the whole of Europe and to meet
political and public demands for transparency, the European CanCer Organisation (ECCO) initiated, together with the European Society for Surgical Oncology (ESSO) and European Society for Radiation Oncology (ESTRO), aninternational, multidisciplinary, outcome-based quality improvement program:
European Registration of Cancer Care (EURECCA). The goal is to create amultidisciplinary European registration structure for patient, tumour and treatment characteristics linked to outcome registration.
To further improve outcomes and diminish variation, EURECCA will establish
the basis for a strong, multidisciplinary, international audit structure that canbe used as a template for similar projects on other tumor types. Both expert
and Delphi rounds as well as real world databases will be a sound structure
for a EU-consensus on diagnosis and treatment of colorectal cancer.
Reference:
Valentini V, Aristei C, Glimelius B, Minsky BD, Beets-Tan R, Borras JM, etal. Multidisciplinary rectal cancer management: 2nd European Rectal Cancer
Consensus Conference (EURECA-CC2). Radiother Oncol 2009;92(2):14863.

S 21

Teaching lecture

45 speaker
UPDATE OF META-ANALYSES AND EBM LEVEL 1 ON: CONCOMITANT AND INDUCTION CHEMOTHERAPY
J. Bourhis

T EACHING LECTUREADVANCES IN REFERENCE DOSIMETRY - WHERE DO WE GO
NEXT?
S. Duane1 , H. Palmans1
1
N ATIONAL P HYSICAL L ABORATORY, Teddington, United Kingdom
Reference dosimetry for external beam radiotherapy using megavoltage xrays is based on measurements, in broad beams, following national and international Codes of Practice such as IAEA TRS-398 and AAPM TG-51. In
the past, treatments would be delivered to patients using beams which typically were not very different from these fields, and the relevance of reference dosimetry was intuitively clear. Advances in treatment techniques suchas IMRT (Intensity Modulated Radiation Therapy) and SRS (stereotactic radiosurgery) involve the use of beams which are very different from those inreference dosimetry. The introduction to mainstream radiotherapy of special purpose machines, such as TomoTherapy, CyberKnife and GammaKnife,
highlights the fact that corresponding advances in reference dosimetry are
overdue.
An international working group on small and composite field dosimetry has
been established by the IAEA, in cooperation with the AAPM, with the aim of
publishing an extension to existing Codes of Practice. They have introduced
the concept of two new intermediate calibration fields: (i) a static machinespecific reference field for those modalities that cannot establish conventional reference conditions and (ii) a plan class-specific reference field which
is closer to the patient-specific composite fields used for treatment. There remain gaps in knowledge and data that must be filled before a comprehensive
Code of Practice can be completed, and which are the subject of continuing
investigation by many research groups.
The aim of this lecture is to provide a short survey of recent progress andcurrent issues in reference dosimetry, with an indication of what we can lookforward to. Topics to be covered include the choice of detectors suitable forabsolute and reference measurements, and practical applications of the new
calibration fields.

Impact of 4DRT and RTTs role
50 speaker
STATE OF ART ON 4DRT - THE PHYSICIST POINT OF VIEW
J. Cuijpers1
1

VU U NIVERSITY M EDICAL C ENTER, Department of Physics and Radiotherapy, Amsterdam, Netherlands
In modern radiation oncology dealing with respiratory motion of tumours andsurrounding tissue imposes a challenging problem in all phases of the treatment process: imaging, target definition, treatment planning and treatment
delivery.
With the introduction of 4DCT, 4D PET-CT and fast MRi a tremendous step
forward has been made in more accurate imaging of mobile tumours and organs at risk in each phase of the breathing cycle. But even 4DCT may still
suffer from motion artefacts due to the finite time resolution of the acquisition
and irregularities in breathing patterns. To assess the quality of the 4DCT
scan at the time of acquisition is an important task of the RTT in clinical practice.
For target volume definition incorporating respiratory motion various approaches exist, like using the Internal Target Volume (the ITV, enveloping
the CTV for every phase of the breathing cycle) or using the mid-ventilation
approach. The delineation of the ITV on the basis of a dynamic 4D scan isa time consuming process. More efficient alternative strategies are needed
without compromising accuracy. The simplest approach is the use of the
maximum-intensity projection but more advanced methods like deformableimage registration are becoming clinically available.
For an accurate dose calculation using the dynamic information of a 4DCT requires the use of advanced non-rigid image registration techniques and accumulation of deformed dose distributions. These techniques are currently not
implemented in commercially available treatment planning systems, requiring
the use of approximate alternatives like the use of the average-intensity projection for treatment planning. In case of lung tumours, appropriate dose calculation algorithms will have to be used to account for tissue inhomogeneities.
A crucial role for RTT’s in the treatment process is the proper setup of patients with mobile tumours using various IGRT approaches. Examples are(gated) planar 2D imaging, with or without implanted markers, or soft tissue
matching on mobile targets using CBCT. For treatment delivery several motion management strategies are applied in clinical practice, like breath hold,
mid-ventilation treatment, gating or tumour tracking. The pro’s and con’s ofthese various issues from a physicists point of view in terms of dosimetry,geometric accuracy and quality assurance will be presented.
51 speaker

START OF ART ON 4DRT - THE RTT POINT OF VIEW
H. McNair1
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiation Technology,
Sutton, United Kingdom
Advances in imaging technology now enables quantification of motion overtime during the imaging, planning, and delivery of radiotherapy i.e 4D information. To apply these techniques effectively and efficiently requires choosing
the method of planning and delivery with respect to individual patients characteristics, methods of immobilisation and the fractionation and dose regime
to be used. An understanding of the different types of internal motion that canoccur is essential. Organ or tumour motion can occur periodically, for example in respiration for patients receiving radiotherapy for lung or liver cancer, or
randomly, which can include respiratory motion or motion of other organs forexample prostate and bladder. Patients need to be assessed individually andthe appropriate method of CT acquisition used to localize the target. If breath
hold or gating techniques are used patient cooperation and training is often
required to fully utilise the benefits of the technique. 4D scanning at planningenables methods such as an internal target volume (ITV), mid ventilation gating or tracking to be used. Techniques to compensate for the random motion
can be more difficult to define and assessment per patient and/or tumour site
is required.
To verify the delivery, 3d/4d soft tissue images are now currently available withvolumetric imaging at treatment. Tumour and patient anatomy changes during the radiotherapy treatment course can therefore be identified. Appropriate
actions such as re planning or on line couch correction must be consideredespecially when hypofractionation or complex treatment planning methods
are used. Specific multi disciplinary staff training and clear communication
within the team and throughout the patient pathway is essential enable decision making and develop guidelines.
Treatment delivery can vary with the method used but often requires moretime which may increase intra fraction motion and can adversely affect the
reproducibility and accuracy of delivery.

S 22

S YMPOSIUM

Symposium

M ONDAY, M AY 9, 2011

Image guided adaptive brachytherapy (IGABT) of cervix cancer enables individualized irradiation, applying high doses to target volume while respecting
organs at risk (OAR) dose constraints. Clear understanding of size and topography of the tumor, OAR and their relations to the applicator is a precondition for IGABT success. Small inconsistencies in definition of these structures
may result in significant uncertainties of optimized dose distribution. This may
compromise treatment outcome, recording and reporting. One of the mostimportant sources of uncertainties is the choice of imaging modality. Various
modalities have been employed in gynaecological IGABT. While US plays animportant role in guiding the insertion of BT catheters, it is used only to alimited extent for contouring. As far as CT and MRI are concerned, variations
in tissue characteristics that influence MR signal are more pronounced thandifferences in X-ray attenuation coefficients. MRI therefore exhibits superior
soft tissue depiction quality than CT, which is further enhanced by its capability of multiplanar imaging. In the 1990’s, early experience with MRI in BT
planning demonstrated its superiority to CT for evaluation of tumor extent,
topography and relations to the applicator [Schoeppel, IJROBP 1992;23(1),Tardivon, Radiographics 1996;16(6), Ptter, Selectr Brachyther J 1991;5(3)]. A
systematic analysis of potential of MRI in cervix cancer IGABT demonstrated
that it enables accurate definition of the regions of interest. [Dimopoulos,
IJROBP 2006;64]. While CT is adequate for OAR delinieation, its value intarget contouring is limited [Viswanathan, IJROBP 2007;68]. MRI has been
recommended for GTV, CTV and OAR contouring and can be consideredcurrent gold standard in cervix cancer IGABT [Haie Meder, Radiother Oncol
2005;74, Ptter, Radiother Oncol 2006;78, Nag, IJROBP 2004;60(4)].
Favourable dosimetric reports on this approach are reflected in encouraging
clinical outcomes. Results of the ongoing prospective EMBRACE study areawaited with enthusiasm (www.embracestudy.dk). Nevertheless, high costand limited access to MRI preclude its early and widespread adoption. In apatterns of care study for BT in Europe in 2002, the use of MRI-based planning was reported by 4.5 and 5 % of centres from European countries withhigh economic wealth and new European countries, respectively. In othercountries, MRI-based dosimetry was not used at that time [Guedea, Radiother Oncol 2007;82(1)]. In 2007, we witnessed an increase of the use of 3D
imaging, in particular CT, for BT treatment planning in Europe [Guedea, Radiother Oncol 2010;97]. In a survey within the ABS, MRI was used as postinsertion imaging at 2% of centres [Viswanathan, IJROBP 2010;76(1)]. In
spite of favourable reports on MRI-based cervix cancer IGABT, its widespread
implementation therefore remains impeded by limited resources, especially inthe countries of central and eastern Europe and the developing world. Strategies to improve availability of MRI or develop technological solutions and recommendations regarding its combination with lower cost modalities such as
CT and US, are therefore essential for the future of cervix cancer IGABT.

and dose volume parameters, primarily due to the higher precision of dosedelivery to the target as compared to 2D brachytherapy. In 2008, the multicentre prospective EMBRACE study was initiated.
Objectives: The aim of the current study (retro-EMBRACE) is to assess clinical outcome of IGABT within a multi-institutional frame prior to the openingof the EMBRACE study.
Material and methods: This study consists of a retrospective consecutive
web-based collection of data from 9 institutions in which IGABT was already routinely performed before 2008 (www.retroembrace.com). All nonEMBRACE patients with stage I-IV locally advanced cervical cancer treatedwith curative intent by means of IGABT and external beam radiotherapy(EBRT) ±concomitant chemotherapy will be included. Availability of an MRIor CT-scan with the BT applicator in place for dose planning purposes ismandatory at least for the first BT fraction. The study comprise multiple parameters (430 in total, with 115 related to follow up) which are based on the
EMBRACE case record forms Equivalent doses in 2 Gy per fraction (EQD2)
values, summing the EBRT and BT doses, were calculated using a/b=3 Gy
for the organs at risk, a/b=10 Gy for tumour, and a half-time for sub lethal
damage repair of 1.5 h.
Results: From October 2010 until now, 175 patients from 9 centres havebeen registered in the RetroEMBRACE database. For 131, data was complete at the time of this analysis. Outcome was based on the reporting on
108 treated with MRI guided BT and 23 with CT guided BT, with a medianfollow-up of 27 month (range 3 - 82). The median age in the study was 54
years (29, 85). According to the FIGO classification, 15 % of the patientswere stage IA-IB, 59 % stage IIA - IIB, 21 % stage IIIA-IIIB and 5 % stage
IV. Histology was squamous cell carcinoma in 82 %, and adenocarcinom or
adeno-squamous carcinom in 14% and 4%, respectively.
EBRT was applied with 3D conformal technique in 88 % of the patients or
IMRT in the remaining 12 %. The median dose to the elective target was 45
Gy (45-50.4 Gy) in 25-28 fractions. Para-aortic EBRT was included in 16 %.
BT was delivered with HDR and PDR in 40 % and 60 %, respectively. The
applicator used was most often a tandem-ring (56 %), followed by tandemovoids (28 %) and the mould technique (14 %). The BT technique was intracavitary only (IC) in 78 %, and combined intracavitary/interstitial (IC/IS) in
22% of the patients at the first implant.
BT dose was most often prescribed to HR CTV (85 %), which had a medianvolume of 34 cm3 (5-132) at the first BT fraction. For D90 of HR CTV and IR
CTV mean values of 88.6±11 Gy and 69± 7 Gy were found. For the organs
at risk, the D2cc values were 76±12 Gy, 63±8 Gy, 62.3±0.4 Gy and 65±8
Gy for bladder, rectum, sigmoid and bowel, respectively.
Among the 108 patients treated with MRI guided BT, five patients had persistent disease and one pt had a local recurrence, resulting in a local control rateof 94 % at a median follow up of 27 months (range 3 - 82). In the CT guided
BT group, one pt had persistent disease and one pt had a local recurrence,
resulting in a local control rate of 91 %, at a median follow up of 27 months(range 3 - 82). Ten deaths occurred among the 131 patients. Mean overall
survival was 83, 7 months (median time for last update: 32 month).
Conclusions: These are the first results from the Retro-EMBRACE database.
However, since only the first 20 - 30 patients were entered by centres, theseresults may not be illustrative, as they are not based on a representative sample. Complete analysis of all RetroEMBRACE patients will produce a moreaccurate conclusion.
Our goal is to collect and analyse data on the estimated 600 patients thathave been treated by IGABT before 2008 in our institutions. This milestone
seems within reach by the end of 2011.

53 speaker

54 speaker

RETRO-EMBRACE: PRELIMINARY RESULTS OF IMAGE GUIDEDBT FOR CERVICAL CANCER IN THE LAST YEARS OF THE 20ST
CENTURY
A. Sturdza1 , J. C. Lindegaard2 , L. U. Fokdal2 , K. S. Nkiwane1 , I.
Chitapanarux3 , A. de Leeuw4 , C. Gillham5 , C. Haie-Meder6 , P. Hoskin7 , R.
Hudej8 , H. Janssen9 , I. M. Jürgenliemk-Schulz4 , G. Lowe7 , R. Mazeron6 ,O. McArdle5 , P. Petric8 , E. Tharavichitkul3 , E. Van Limbergen9 , C. Kirisits1 ,K. Tanderup2 , R. Pötter1
1
M EDICAL U NIVERSITY V IENNA, Department of Radiotherapy, Vienna,
Austria2
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
3
C HIANG M AI U NIVERSITY H OSPITAL, Chiang Mai, Thailand
4
U.M.C. U TRECHT, Department of Radiotherapy, Utrecht, Netherlands
5
S T L UKE ’ S H OSPITAL, Dublin, Ireland Republic of
6
I NSTITUT G USTAVE R OUSSY, Department of Radiotherapy, Villejuif, France
7
M OUNT V ERNON H OSPITAL, Department of Radiotherapy, Northwood
Middlesex, United Kingdom
8
I NSTITUTE OF O NCOLOGY L JUBLJANA, Division of Radiotherapy, Ljubljana,
Slovenia
9
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Radiotherapy,
Leuven, Belgium

EMBRACE UPDATEK. Tanderup1 , J. C. Lindegaard1 , C. Kirisits2 , K. S. Nkiwane2 , E. Fidarova2 ,Evolution of MRI guided BT in cervix
52 speaker
MRI-BASED BRACHYTHERAPY IN CERVIX CANCER: WHERE ARE
WE NOW?
P. Petric1
1
I NSTITUTE OF O NCOLOGY L JUBLJANA, Department of Radiotherapy,
Ljubljana, Slovenia

Background: Image guided adaptive brachytherapy (IGABT) for cervicalcancer has been developed during the last 10 years. Until recently, publishedmono-institutional data have shown major improvement in clinical outcome

C. Haie-Meder3 , P. Hoskin4 , P. Petric5 , I. M. Jürgenliemk-Schulz6 , E. Van
der Steen-Banasik7 , E. Van Limbergen8 , U. Mahantshetty9 , M. Sundset10 ,R. Pötter2
1
A ARHUS U NIVERSITY H OSPITAL, Aarhus C, Denmark
2
M EDICAL U NIVERSITY V IENNA , AKH, Vienna, Austria
3
I NSTITUT G USTAVE R OUSSY, Villejuif, France
4
M OUNT V ERNON H OSPITAL, Northwood Middlesex, United Kingdom
5
I NSTITUTE OF O NCOLOGY L JUBLJANA, Ljubljana, Slovenia
6
U.M.C. U TRECHT, Utrecht, Netherlands
7
ARTI - A RNHEMS R ADIOT HERAPY I NST., Arnhem, Netherlands
8
U NIVERSITY H OSPITAL G ASTHUISBERG, Leuven, Belgium
9
TATA M EMORIAL H OSPITAL, Mumbai, India
10
S T. O LAVS U NIVERSITY H OSPITAL T RONDHEIM, Trondheim, Norway

M ONDAY, M AY 9, 2011
treatment has been completed and reported in 253 patients at the time ofanalysis. Outcome is based on the reporting on 188 patients with a medianfollow-up time of 9 months. The median age of patients in the data extract
was 50 (24-91), performance (WHO) 0-1 in 96% and median haemoglobin
7.9 (4.0-11.4) mmol/l. Hydronephrosis was seen in 9%. FIGO stage distribution showed IB1 4%, IB2 17%, IIA 8%, IIB 45%, IIIA 1%, IIIB 20% and stage
IV 5%. Histology was squamous cell in 82%, adenocarcinoma in 14% andadeno-squamous in 4% of the patients, respectively. Maximal tumour diameter on MRI at diagnosis was more than 50 mm in 57% and 32% had PET-CTor cytological/histological positive nodes.
EBRT was given with 3D conformal technique in 81% and IMRT in 19%.
The median dose to the elective target was 45 Gy (45-50) in 25 fractions.
Para-aortic EBRT was included in 17% of the patients. Nodal boost giving
additional 10-20 Gy by EBRT was given to 33% of the patients (mostly external/internal iliac nodes). Parametrial and/or tumor-boost by EBRT was hardly
used (1%). Concomitant chemotherapy was given to 92% of patients mostly
as weekly Cisplatin (95%).
Brachytherapy was delivered with HDR and PDR in 45% and 55% of thepatients, respectively. The applicator used was most often a tandem-ring(52%), followed by tandem-ovoids (24%) and the mould technique (17%).
The BT technique was intracavitary (IC) only in 71% and combined intracavitary/interstitial (IC/IS) in 29% at the first implant. IC/IS was more frequently
used for repeated implants (33-47%). The dose of BT was most often prescribed to HR CTV (83%). The median volume of the HR CTV at first BT
fraction was 29 cm3 ranging from 10-130 cm3.
EQD2 values adding the dose of EBRT and BT were calculated using a/b=3
OAR and a/b=10 for tumour and a repair halftime of 1.5 h. For D90 of HR CTV
and IR CTV mean values of 88.6±12.5 Gy and 68.7± 6.8 Gy was found. For
OAR the D2cc values were 76.1±13.4, 63.8±8.9, 62.3±6.9 and 63.4±9.7
Gy for bladder, rectum, sigmoid and bowel, respectively.
So far 2 patients with persistent disease and 3 patients with local recurrencesin the BT target volume have been reported, yielding a 1 year local controlof 97±2% (SE). Three of the 5 local failures were adenocarcinomas and all
5 failures were seen in large tumours (>50 mm on MRI at diagnosis). Radical salvage hysterectomy was possible in 2 of these cases. Eight patients
have died, 4 from disease progression which generates an actuarial overall
survival at 1 year of 94±2% (SE). For morbidity (CTCAEv3.0) 3 pts have experienced G3 morbidity (oedema, pain, osteo and soft tissue radionecrosis)
and 2 pts G4 vaginal stenosis.No G3-4 bladder and gastro-intestinal morbidity has so far been encountered. HR QoL questionnaire (EORTC QLQ
C30+CX24) based on a high response rate (82%) points to fatigue, insomnia,
menopausal symptoms as the dominating quality of life impairments following
treatment.
In conclusion, the EMBRACE study is recruiting well and already showpromising data both with regard to dissemination of image guided adaptive
BT based on MRI in a multicentre setting and with regard to outcome including HR QoL. The goal of accruing 600 patients by 2012 seems within reachand based on the data reported so far it will be possible to fulfil the many aimsof the study.

S YMPOSIUM

Symposium
Dose calculation beyond TG43: impact on clinicians and requirements from vendors
55 speaker
WHY WE SHOULD MOVE BEYOND TG43 AND WHAT TG186 WANTS
TO ACCOMPLISH
L. Beaulieu1
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Quebec, Canada
Contrary to external beam radiotherapy (EBRT), the brachytherapy (BT) community has not widely adopted heterogeneity-correction algorithms. Yet, BT
dose calculation accuracy is highly dependent on scatter conditions and photoelectric effect cross-sections relative to water. In specific situations (e.g.,shielded applicators), differences between the current water-based BT dose
calculation formalism (TG-43) and advanced model-based dose calculation
algorithms (MBDCA) can lead to differences in dose calculation exceeding afactor of ten. In other to take these differences into account accurately, theintroduction of new dose calculation algorithms is inevitable and one MBDCA
is already commercially available.
The goal of Task Group 186 is to provide guidance to early MBDCA adopters.
It addresses major issues not tackled by current brachytherapy guidance documents related to handling of radiation transport and scoring medium, thepatient/treatment modeling and commissioning of MBDCA. Specific recommendations are made to ensure that better dose calculation tools are not introduced in the clinics at the expense of worldwide uniformity gain by TG-43
implementation. When data were found to insufficient, interim recommendations were made and potential areas of research identified.
On behalf of AAPM TG-186: L. Beaulieu, A. Carlsson Tedgren, J-F. Carrier,
S. D. Davis, F. Mourtada, M. J. Rivard, R. M. Thomson, F. Verhaegen, T. A.
Wareing, and J. F. Williamson.
56 speaker
TRANSPORT AND SCORING MEDIUM: STATUS AND IMPACT
R. Thomson1
1
C ARLETON U NIVERSITY, Ottawa, Canada
In brachytherapy, the current standard of practice is for water to be used as
the medium for both radiation transport and dose specification, Dww. However, MBDCAs offer the possibility of modeling radiation transport in realistic patient and treatment geometries, including applicators, skin surface contours, and biological tissues. Modeling radiation transport in non-water media
requires the selection of a medium for dose specification: dose to the local
tissue composing each voxel, Dmm, or to a fixed reference medium such as
water, Dwm, regardless of the composition of the underlying voxels, may bereported.
Differences between Dmm, Dww, and Dwm can be significant and depend
on source energy. These differences are most significant for photons withenergies below 50 keV and can be as high as 70%-80% for soft tissues anda factor of seven for bone, due to the the behavior of mass energy absorption
coefficients at these energies (Fig. 1). Differences between Dmm and Dwm
are generally within 3%-5% for higher energy sources (e.g. 192Ir), raising up
to around 15%-25% in bone.
Radiation transport should be simulated using the most accurate tissue composition assignments available. As research regarding the choice of dosescoring medium is ongoing, a definitive recommendation for either Dwm or
Dmm is still premature; however, both often differ significantly from current
water-based standard of practice.
On behalf of AAPM TG-186: L. Beaulieu, A. Carlsson Tedgren, J-F. Carrier,
S. D. Davis, F. Mourtada, M. J. Rivard, R. M. Thomson, F. Verhaegen, T. A.
Wareing, and J. F. Williamson.
57 speaker
ASSIGNING THE CORRECT CROSS SECTION FROM IMAGING
DATA: WHY THIS NEEDS TO BE DONE: RECOMMENDATION
F. Verhaegen1
1

As of Nov 2010 the first data extract has been made and analyzed from theInternational study on MRI guided brachytherapy in locally advanced cervical cancer (EMBRACE). The study include stage I-IV locally advanced cervical cancer treated with external beam radiotherapy (EBRT), concomitantchemotherapy and MRI guided brachytherapy (BT) with curative intent. The
protocol requires strict use of EBRT but is open to institutional dose prescription of BT as long as the GEC ESTRO guidelines are employed and MRI
with the BT applicator in situ is used for BT dose planning. Concomitantchemotherapy is based on weekly Cisplatin (40 mg/m2).
Since July 2008 EMBRACE has recruited 305 pts from 19 centres. Of these,

S 23

MAASTRO C LINIC, Maastricht, Netherlands

Model based dose calculation algorithms in brachytherapy require assignment of interaction probabilities on a voxel-by-voxel basis to compute dose.
In brachytherapy, the dose is administered by photons with lower energies(20 keV 1 MeV). The lower the photon energy, the larger the differences
are between media in terms of interaction coefficients. Sensitivity analysesof Monte Carlo dose calculations to exact tissue composition have been reported recently.
It is recommended to extract material densities from calibrated CT images.
To fully identify the correct medium, information on e.g. the effective atomic

S 24

S YMPOSIUM

number is also needed. This is currently not possible with standard CT scanners, but may become possible with e.g. dual-energy CT scanners, or byusing other imaging modalities such as MRI or ultrasound imaging. In the
meanwhile, the TG-186 report will recommend some standard compositions
for e.g. breast and prostate tissues. A scheme to determine the fraction of
adipose and glandular breast tissue is introduced. Topics such as calcifications are also discussed. The correct media assignment in applicators andshielding is also mentioned. Several material assignment methods are discussed and topics for further research are identified.
On behalf of AAPM TG-186: L. Beaulieu, A. Carlsson Tedgren, J-F. Carrier,
S. D. Davis, F. Mourtada, M. J. Rivard, R. M. Thomson, F. Verhaegen, T. A.
Wareing, and J. F. Williamson.
58 speaker

M ONDAY, M AY 9, 201160 speaker
DOSE CONFORMITY AND ESCALATION: DID WE REALLY DECREASE SIDE EFFECTS AND INCREASE TUMOR CONTROL?
C. Nutting
Abstract not received.

61 speaker

TESTING: NEW TREATMENT COMBINATION
G. Lammering1

WILL CONCOMITANT CHEMO-RADIATION STILL BE USED IN THE
AREA OF EGFR INHIBITORS?
K. Harrington

1

Abstract not received.

There are numerous guidance documents covering various aspect of the TPS
commissioning process. However, to our knowledge there is no literature providing quantitative information or practical guidance on the commissioning ofbrachytherapy MBDCA for clinical use. TG-186 recommends two levels ofcommissioning tests that should be performed in addition to TPS QC/QA recommendations already in place based on societal guidelines.
In level 1, the clinical medical physicist should determine agreement of MBDCA TPS-derived dosimetry parameters in comparison with values of AAPM
consensus TG-43 dosimetry parameters for a given brachytherapy source
model. Calculations should be conducted in the reference condition i.e. water medium providing full scatter conditions at distances up to 10 cm awayfrom the source.
In level 2, the direct comparison of the MBDCA output to a reference treatment plan having heterogeneous media and scatter conditions is mandatory
for physicists to commission MBDCA-based TPS. Comparisons of the 3D
dose distributions calculated with the clinical MBDCA-based TPS should be
independently verified against virtual phantoms mimicking the clinical scenarios. TG-186 is proposing a detailed commissioning workflow in which validated test case plans would be available (e.g. via a website) under DICOM
RT format to the community. Furthermore, TG-186 recommends the creationof a Working Group whose tasks would be to determine prerequisites for suchplans to be accepted as reference datasets and ensuring vendor uniformity.
On behalf of AAPM TG-186: L. Beaulieu, A. Carlsson Tedgren, J-F. Carrier,
S. D. Davis, F. Mourtada, M. J. Rivard, R. M. Thomson, F. Verhaegen, T. A.
Wareing, and J. F. Williamson.

HOW SHOULD WE MANAGE PATIENTS WITH LOCOREGIONALLYADVANCED HEAD AND NECK CANCER WHO ARE NOT SUITABLEFOR CHEMO-RADIOTHERAPY ?
B. O’Sullivan1
1
P RINCESS M ARGARET H OSPITAL, Toronto, Canada

59 speaker
THE NEW DISEASE: HOW TO DEAL WITH THE HPV POSITIVE AND
NOT TO LEAVE THE HPV NEGATIVE BEHIND?
L. Licitra
Abstract not received.

ESTRO-ESSO Joint Symposium: Rectal cancer What is the evidence-base that is being createdright now? - The best of clinical trials
63 speaker

COMMISSIONING TPS BEYOND TG43: LINK TO TG43 UNDERLYINGPROCESS AND GOING FORWARD DISCUSSION
F. Mourtada1
1
U.T. M.D. A NDERSON C ANCER C ENTER, Houston, TX, USA

Head & Neck cancer- What is the evidence that isbeing created right now? - The best of clinical trials

M ONDAY, M AY 9, 201162 speaker

Purpose: Concurrent chemoradiotherapy (CRT) is generally the standard ofcare for loco-regionally advanced (stage III & IV) mucosal head and necksquamous cell carcinoma (LA-HNSCC). However, for various reasons, not all
patients are suitable for chemotherapy or can tolerate the intensity of multimodality protocols. Managing this burgeoning patient population is challenging. The intent of this presentation is to outline and review currently available
treatment options and outcomes for LA-HNSCC patients unsuited to CRT
using reasonable principles of management generally, information from thepublished literature where possible, and an assessment of our prospectively
acquired institutional experience.
Methods: A literature search was conducted for papers published between
2001 and December 2010 addressing the options and outcomes for LAHNSCC patient unsuited to CRT. A retrospective review of our prospective
head and neck anthology data base was also conducted for LA-HNSCC
treated with radiotherapy alone (i.e. without chemotherapy) between 20032009. Criteria for inclusion comprised patients medically unfit for chemotherapy, poor performance status affecting tolerance to chemotherapy, and theelderly where the potential benefit of chemotherapy would be offset by thedeleterious impact of intensive treatment.
Results: No clear definition exists in the literature to define the population"unfit for chemotherapy". There was also a paucity of data describing thetreatment options and outcomes for these patients with LA-HNSCC. Potential approaches generally include radiation alone by conventional fractionation with or without dose and /or radiation target volume modification, altered fractionation radiation schedules in patients of reasonable performancestatus, bio-radiation (e.g. generally combining anti-EGFR agents), and conservative surgery with moderate adjuvant radiation protocols employing reduced dose and / or irradiated volumes in comparison with conventional protocols. In our institutional experience, 578 stage III-IV mucosal HNSCC weretreated with radiation alone between 2003-2009, including 254 oropharynx,
160 larynx, 46 oral cavity, 45 hypophayrnx, 11 nasal cavity and paranasal
sinus, and 62 unknown primary with cervical lymph node metastasis. Nasopharynx was not included. Of these, 218 patients were >70 years oldwhile the remaining 360 patients received radiation alone for the following
reasons: medical contraindication to chemotherapy (e.g. liver, kidney, or pulmonary dysfunction), poor performance status, low volume neck disease, andpatient refusal of chemotherapy. Radiation regimens included conventional
fractionation (70Gy/35f/ 7 weeks: 86) or various altered fractionation schedules: (60Gy/25f/5 weeks, QD: 200; 66Gy/30f/6 weeks, QD: 11; 70Gy/35f/6
weeks, QD, BID once per week: 49, and very accelerated BID fractionation
64Gy/40f/4 weeks: 232). The outcome of these patients is under analysis
and will be reported.
Conclusions: The treatment approaches for LA-HNSCC patients unsuitablefor chemotherapy are varied and should be applied selectively. Outcome data
are scarce and the optimal treatment strategies for this growing population ofpatients merits further study including potential clinical trials designed to address their particular needs.

D EPARTMENT OF R ADIATION O NCOLOGY (MAASTRO), GROW - S CHOOLFOR O NCOLOGY AND D EVELOPMENTAL B IOLOGY, M AASTRICHT U NIVERSITYM EDICAL C ENTER, Maastricht, Netherlands

The treatment response to radiotherapy (RT) of rectal cancer is known to bevery heterogeneous between patients, which is often related to resistance oftumor cells to radio- and chemotherapy. Extensive research in recent years
has stimulated the development of promising targeted drugs against cancer-specific biological pathways in order to overcome this resistance. However,
due to the biological heterogeneity of the tumors as well as the specificityof these drugs, not all patients will probably benefit from the combination ofthese compounds with RT and/or chemotherapy. Thus, modern trials testing these combinations need to integrate high quality translational researchin order to identify biological and imaging criteria as predictors of response.
This is especially important in case of a negative trial, because such negative
trial can still provide important information on possible molecular or imaging based subgroups that benefited from the combination etc. One recent
example is the trial combination of the EGFR-targeted drug Cetuximab andchemoradiotherapy in rectal cancer, which failed to improve the local tumor
response in the tested patient cohort.
Preclinical studies from our lab and others have been able to identify the cellular phosphatidol- inositol -3K (PI3K) pathway as an important mediator ofresistance to RT. Activation of the PI3K pathway is a recurrent feature observed in several human tumors. Improvements in understanding the molecular aberrations underlying resistance of tumor cells to radiotherapy have led
to the identification of the PI3K-Akt pathway as an important central cascade
contributing to a more radioresistant phenotype. This is further supported by
the fact that several other important known molecular contributors to radioresistance, e.g. EGFR family, IGF1R, k-ras and PTEN, which are also often
mutated or amplified, all feed into the PI3K-Akt cascade. Consequently, targeting the PI3K-Akt pathway during radiotherapy of solid tumors has gained
high priority in clinical research. Recently, molecular analysis of the tumor
specimen from the DUTCH TME trial has also revealed important new information on the important role of the PI3K in the local control of rectal cancer
after radiotherapy.
This has stimulated clinical translational research projects, in which early clinical trials are testing the safety and efficiency of molecular targeted drugs
known to modulate the activity of the PI3K in combination with RT. Repeatedhigh quality imaging with dynamic contrast- enhanced MRI and FDG-PET/CT
as well as biology- based high technology research of repeated tumor andblood samples before, during and after mono- and combined treatment will
provide important insight into the biological effects of the tested drugs andwill enable us to define predictive criteria of tumor response to the tested
agents. Several other drugs are being tested at the moment in combination
with radio- and/or chemotherapy in rectal cancer in order to improve the local
tumor response. I will try to give a comprehensive overview of the currently
available data regarding the ongoing treatment combinations in rectal cancer.
64 speaker
ONLY PREOPERATIVE LOCO-REGIONAL AND SYSTEMIC THERAPY IN RECTAL CANCER - THE RANDOMIZED RAPIDO TRIAL
B. Glimelius12
1
U PPSALA U NIVERSITY H OSPITAL A KADEMISKA S JUKHUSET, Uppsala,Sweden2
K AROLINSKA I NSTITUTET, Department of Oncology-Pathology, Stockholm,
SwedenBackground: Surgery is the main treatment in rectal cancer, but clinicallyimportant gains can be achieved by additional treatments given pre- and/or
postoperatively. It was early found that preoperative radiotherapy (RT) was
superior to (more dose efficient, less toxic) postoperative RT and although it
took decades for many clinicians and scientists to accept this and change routines, preoperative treatment is presently the recommended approach. The
advantage of postoperative (chemo)radiotherapy (C)RT is that the information
about stage and other prognostic risk factors is available from the pathological examination.
Improved surgical techniques together with a use of preoperative (C)RT topatients with tumours at high risk for a local failure have reduced the local
failure rates to below 10% at most sites. Overall survival has however not
been improved to any major extent because many patients die from systemic
metastases. Postoperative adjuvant chemotherapy has been given to reduce

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the risk of recurrence, but strong proofs for this are not available from randomized trials when the loco-regional therapy has been optimized.
Treatment of rectal cancer is presently based upon risk of local and systemic
therapy. In the most locally advanced tumours, the "ugly" group, constituting 15-20% of newly diagnosed patients, the most widely used treatment today is CRT to about 50 Gy with 5-fluorouracil (oral capecitabine), surgery
followed by adjuvant chemotherapy for six months depending upon postoperative stage.
Study design: Whether preoperative or neo-adjuvant chemotherapy has
better effects than postoperative adjuvant chemotherapy will be tested in a
"Randomized Multicentre Phase III study of short course RT followed by prolonged pre-operative chemotherapy in primary high risk rectal cancer compared to standard CRT and adjuvant chemotherapy", the RAPIDO trial. Patients with a newly diagnosed non-metastatic rectal cancer with at least oneof the following risk factors (cT4, cT3 mrf+, EMVI+, N2, lateral node positivity) based upon staging with magnetic resonance imaging will be randomized
between an experimental arm and a reference arm. In the experimental arm,
patients will start with short-course RT (5 x 5 Gy in 1 week), 6 cycles ofcapecitabine/oxaliplatin (XELOX) and surgery. Reference treatment is CRT
with 28 x 1.8 Gy plus capecitabine, surgery and postoperative 8 cycles of
XELOX. The primary endpoint is 3 year disease-free survival and 842 patients are planned to be included to show an increase in progression-freesurvival from 50% to 60%.
Discussion: It is hoped that this multicentre trial run by the Nordic and Dutch
Colorectal Cancer Groups will set a new standard of care. Patient inclusionis planned to start in spring 2011 and the inclusion period is anticipated to be
3 years.
65 speaker
TESTING: NEW SUBGROUP BASED TAILORED STRATEGIES
M. A. Gambacorta1
1
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Department of Radiation
Oncology, Roma, Italy
Although surgery remains the curative treatment of rectal cancer, several randomized trials demonstrated a benefit from the addiction of preoperative radiotherapy with a significant increase of local control. However none of thestudies demonstrated a survival benefit even with the addiction of chemotherapy to radiation.
Subgroup analyses of patients treated with short course radiotherapy, clearlystated the uselessness of this strategy in both early and in very advanced
tumors (positive Circumferential Resection Margin), whereas a significant advantage was recorded for intermediate tumors.
On the other hand preoperative long course radiotherapy, due to the intensification given by concomitant chemotherapy and the possibility to achieve
a tumor downstaging in the awaiting time between radiotherapy and surgery,has a higher clinical benefit in patients with advanced tumors (cT4, CRM+).
Moreover, after preoperative chemoradiation a variable percentage of pathological complete response (pCR) specimens is reported. Although some series show no correlation, many series report that patients who achieve a pCR
following preoperative chemoradiation have improved long-term outcomes interms of excellent local control rates, independent of their initial clinical T
and N stages. These data support the concept of heterogeneity among rectal
cancers and the need to identify reliable markers to detect favourable patients
who could be cured with less aggressive therapies.
Although biopsy based molecular biomarkers are not yet available in clinicalpractice, we have now the availability of molecular imaging which seems topredict response to oncologic treatments.
All these parameters need to be managed inside a multidisciplinary team, inwhich clinical strategies are adapted according tumor presentation and tumor
response to therapy. In rectal cancer can be recognized 3 main steps to makeclinical decision: 1) after initial staging (type of preoperative treatment); 2) after neoadjuvant treatment before surgery (type of surgery) 3) after surgery(type of adjuvant treatment and follow-up).
In this time of changing diagnostic and therapeutic approaches, a common
standard for large heterogeneous patient groups will likely be substituted bymore individualized therapies.
However the management of all the parameters driving the clinical decision
can result difficult. Tools such as learning machine, ROC curve platforms
for heterogeneous knowledge and nomograms (a statistical tool that enables
users to calculate the overall probability of a specific clinical outcome for anindividual patient) will be helpful to defined tailored strategies and drive theresearch in rectal cancer.

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M ONDAY, M AY 9, 2011

Symposium

to new paradigms in radiotherapy combined with systemic treatment.

Functional imaging for tumour and normal tissue
characterization

Novel dosimetry methods

66 speaker

69 speaker

FUNCTIONAL MR IMAGING FOR DELINEATION AND CHARACTERIZATION OF PROSTATE TUMOURS
G. Groenendaal1 , A. Borren1 , M. Moman1 , J. Korporaal1 , M. Philippens1 ,M. van Vulpen1 , U. van der Heide1
1
U.M.C. U TRECHT, Utrecht, Netherlands
As evidence is emerging that local recurrences of prostate tumors are often
seen at the original tumor location, an additional boost dose to this tumor
could improve the tumor control probability. By limiting the boost to the visible
tumor, the toxicity to the organs at risk may be kept at a minimum level. Recently, a randomized phase III trial started to investigate the benefit of a focal
lesion ablative microboost (FLAME trial).
Magnetic resonance imaging (MRI) techniques such as diffusion weighted
imaging (DWI) and dynamic contrast enhanced (DCE) MRI have a high sensitivity and specificity for tumor detection. However, for a more widespread
application in radiotherapy, the robustness of the techniques must be improved. As data from multiple MRI techniques reflect tumor heterogeneity
validation of this heterogeneity with pathology is required to identify whichparts of the suspected volumes should be included in the target volume fordose escalation. A relatively simple method to deal with this heterogeneity
would be to use target volumes for different risk levels. This can be improvedby using automated methods to translate multiparametric data into appropriate segmentations.
One approach to improve the robustness of target definition is the use of a logistic regression model. We created a model predicting the presence of tumor
on a voxel-by-voxel basis inside the peripheral zone from DWI and DCE-MRI
images. This model was derived from suspicious and non-suspicious regions
delineated in 85 radiotherapy patients.
The model contained the value of the DWI and DCE-MRI parameters as wellas the minimum and maximum value in the adjacent voxels. The location of
the voxel inside the peripheral zone was also included.
The performance of the logistic model was validated on 11 prostatectomy
patients. On average for all 11 patients, the area under the curve (AUC) retrieved from an ROC analysis was 0.88.
This high value for the AUC suggests that this model is useful for clinical application. This could be used directly in a voxel-based dose painting approach.
Alternatively, the model can be used to identify regions with a high positive
predictive value as GTV. Furthermore, a threshold with a high negative predictive value could be used. Voxels with values lower than the threshold willvery likely not contain tumor tissue, whereas voxels with model values above
this threshold could be considered as ’high-risk CTV’. An example of this approach is shown in figure 1.
In conclusion, DWI and DCE-MRI are valuable techniques for tumor delineation in the peripheral zone of the prostate. The use of a logistic regression
model enables objective interpretation of the images. Tumor probability maps
created by this model could serve as an input for dose planning. In this way
the robustness of dose plans for focal boost therapy of the prostate can begreatly improved.

M ONDAY, M AY 9, 2011

3D DOSIMETRY SYSTEMS - GELS, EPIDS AND OTHERS
M. Duchateau1 , D. Verellen1 , T. Depuydt1 , K. Tournel1 , T. Reynders1 , T.
Gevaert1 , K. Leysen1 , A. Gulyban1 , K. Poels1 , M. De Ridder1
1
UZ B RUSSEL O NCOLOGY C ENTRE, Radiotherapy, Jette, Belgium

67 speaker
FUNCTIONAL IMAGING WITH MRI FOR NORMAL TISSUE RESPONSE IMAGING
Y. CaoAbstract not received.

68 speaker
IMAGING OF RESIDUAL DISEASE IN NSCLC: TOWARDS DOSEPAINTING BY VOLUMES
H. Aerts1 , P. Lambin1 , D. De Ruysscher1
1
MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS TRICHT, Radiation Oncology, Maastricht, Netherlands
Despite major advances during the past decades of the treatment of patientswith advanced cancer, local tumour failure is still very common. To overcome
this problem, the concept of dose painting has been introduced, i.e. guiding the radiotherapy dose towards intra tumour treatment-resistance areasof drugs and radiation. Indeed, high precision radiotherapy is a treatment
modality that enables directing a therapeutic effect in space and time, whilst
still combinations with systemic therapy are possible. Although the concept ofdose painting has been introduced some years ago, many have been sceptic
about the embarkation of dose painting trials, mainly because of the paucityof quantifiable data on the relationship between image characteristics, radioresistance, and failure patterns within the tumour, the uncertainty on the image resolution and related the accuracy of the imaging that is needed, and toa lesser extend the technical impossibility to deliver radiation with voxel-wisedifferences with steep dose gradients. However, recent results of several
groups have shown that it is possible to identify the intra tumour location withthe highest probability of relapse before treatment starts using different imaging modalities. Also are these regions are sufficiently large for current dosedelivery techniques (Lambin et al, 2010). Therefore we postulate that there
is sufficient scientific basis to test dose painting in clinic trials, which can lead

Treatment modalities are becoming more and more complex in order to enable advanced patient treatments with a higher dose to the tumor while sparing the organs at risk. The last couple of years a lot of new treatment techniques and modalities became commercially available such as Intensity modulated radiotherapy (IMRT), Helical Tomotherapy, gated treatments, tumor
tracking, VMAT, RapidArc, IMAT, dynamic delivery techniques (leafs, gantry
and couch), flatness filter free (FFF) designs, etc..
Although the compliance rate for beam calibration is improving and near 98%
for both photon and electron beams, increasing treatment complexity leads
to more technically advanced components in the treatment chain, possibly inducing discrepancies. Credential audit results from the Radiological Physics
Center (RPC) indicate that roughly 30% of the institutions failed to deliver an
IMRT dose distribution to a head and neck phantom that agrees with their own
treatment plan to within 7% or 4mm. So, even though the use of advanced
dosimetry equipment for QA is wide spread, it seams that a lot of caveats arestill present in the QA chain of advanced treatment techniques.
The choice of a specific QA system depends on the number of treatment parameters to be verified and the extensiveness of the desired QA process. For
this choice the use of the conceptual pyramid was proposed by De Wagter
et al. In this conceptual pyramid the treatment chain is divided into 4 levelsof specificity, all based on the stability of the underlying levels. On top of the
pyramid (level 4) we can find the 3D dosimetry of the entire treatment delivery.
Descending brings us to level 3 where we find the 1D-2D dosimetry of individual beam components. Level 2 is the planning system and data consistency
QA level and at the ground level (level 1) we find the machine QA level.The
best way to use the conceptual pyramid is the top down approach where a
3D dosimetry of the entire treatment is delivered to a phantom. When the results show discrepancies, lower levels of the pyramid should be sought to findanswers. 3D dose distributions are QA’ed using different types of dosimeterssuch as; film (EDR2 and EBT2), diode arrays, ionization chamber arrays,
EPID detectors, MVCT imaging detectors, etc...
Is this talk we will try to give a general overview of dosimetry techniques used
to QA 3D dose distributions and we will try to answer some questions:- What techniques are used and are the QA tools keeping up with the rapid
evolutions of the treatment machine manufacturers ?
- How are they applied in the different levels of the conceptual pyramid ?
- Is 3D really 3D ?
- Where do they stand compared to the ’ideal’ dosimeter ?
- What are the pros and cons of each group of dosimeters ?
- How do they fit in the workflow ?
70 speaker
ONLINE LUMINESCENCE DOSIMETRY
C. E. Andersen1
R ISØ N ATIONAL L ABORATORY, T ECHNICAL U NIVERSITY OF D ENMARK,
Department of Medical Physics, Roskilde, Denmark

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heads. RL dosimetry based on plastic scintillators were found to be of particular interest due to their direct water equivalence (i.e. such detectors do
not cause significant perturbation of the radiation field in a water phantom
or a patient) and they have a fast (ns) time-response which allows for doseper-pulse measurements in linear accelerator beams. The prime challenges
with RL/OSL dosimetry was found to be ionization quenching (i.e. lack ofproportionality between absorbed energy in the detector and light output for
highly dense ionizations) and interference by light signals generated in the optical fiber cable during irradiations. The most promising uses of fiber-coupled
RL/OSL dosimetry seemed to be online time-resolved in vivo dosimetry (especially for remotely afterloaded brachytherapy and diagnostic radiology) andgeneral quality assurance equipment for external-beam radiotherapy (for example, scintillator arrays tailored for measurements in small fields or dynamic
treatments).
71 speaker
LITHIUM FORMATE EPR DOSIMETRY FOR DOSIMETRY VERIFICATIONS IN RADIOTHERAPY
S. Olsson1
1
L INKÖPING U NIVERSITY H OSPITAL, Radiation Physics, Linköping, Sweden
Electron paramagnetic resonance (EPR) dosimetry with alanine is becoming more and more appreciated as a dosimetry method in radiotherapy due
to its broad linear dose range and low energy dependence. The alternative
dosimeter material lithium formate has a sensitivity that is at least a factor of
two higher than alanine. In addition, the material is even more tissue equivalent than alanine regarding mass energy absorption coefficient and stopping
power, which makes the signal more independent of beam quality. The dependence of linear energy transfer (LET) of the signal is an important aspect
both for applications with heavy particles and for brachytherapy applications
with low photon energies. For photons, a small LET dependence, 5-6%, forenergies below 100 keV has been found, but there are no signs of any dose
rate dependence. For high LET beams, a strong LET dependence of thesignal have been observed, comparable to earlier results for alanine and ammonium tartrate. Another feature of lithium formate is that the spectrum has
only one peak whereas alanine has five. This makes the material possible touse for EPR imaging where a 2D or 3D dose distribution in a small volume
can be obtained with a high spatial resolution.
However, the suitability for applications such as dosimetry audits, measurements under non-reference conditions and brachytherapy also includes morepractical aspects. One is the possibility to make pellets. The material canbe pressed to pellets manually, but more work is needed to develop an automated process. Another practical aspect is how the signal is affected byhumidity as well as storing and readout temperature. The time dependenceof the signal is affected primarily by air humidity in a complex process thatis not yet fully explored. The influence of short-time storing temperature has
been tested and found to be insignificant in the range -20◦ C to +40◦ C. A
more thorough study of the time dependence is initiated, primarily to finda robust method for dosimetry audits with measurements in non-reference
conditions. A pilot-study with such a system for dosimetry audits has been
performed with promising results. Lithium formate has also successfully beentested for applications such as pre treatment verification of an IMRT plan andphantom measurements in stereotactic radiosurgery, as well as for measurements around 192 Ir brachytherapy sources.
Once the manufacturing and time dependence issues are solved, EPR
dosimetry with lithium formate will be valuable as a complement to other clinical dosimetry methods.

1

Radioluminescence (RL) and optically stimulated luminescence (OSL) fromcertain phosphors can be used for dosimetry in diagnostic and therapeutic
radiology, and RL/OSL dosimetry is an active area of research for several
groups. The objective of this work was to outline and review the current status of this field. RL/OSL dosimetry is entirely based on optical signals, and
it is therefore possible to perform online real-time read out using thin opticalfiber cables and remotely placed instrumentation. Fiber-coupled RL dosimetry can be carried out on the basis of a fraction of a mg of plastic scintillator
material attached to a 10-20 m long optical fiber cables of plastic. During
irradiation, such a dosimeter probe spontaneously emits RL in proportion to
the instantaneous dose rate at the point of the scintillator. The luminescenceintensity can be detected with photomultiplier tubes, CCD cameras or otherhighly sensitive photodetectors. Some crystalline inorganic phosphors, suchas carbon-doped aluminium oxide (Al2O3:C) have the ability to store charge
produced in the crystal during irradiations. The stored charge may later bereleased by fiber-guided laser light under emission of OSL. This OSL signal therefore reflects the passively integrated dose since the dosimeter waslast read out. In contrast to thermoluminescence dosimetry, fiber-coupled
OSL dosimetry may be performed in vivo while the dosimeter is still in thepatient. Some of the attractive features of RL/OSL dosimetry was found tobe: sub-mm detector size, high dynamic range (below a mGy to several Gy),
and absence of electrical wires or other electronics in the dosimeter probe

From conventional to advance practice on miscellaneous treatments
72 speaker
CURRENT STATUS ON TOTAL SKIN ELECTRON IRRADIATION
S. Hynds1 , D. Irvine2 , R. Houston1 , P. Henry1 , S. Stranex1 , J. McAleer1 , J.
O’Sullivan13
B ELFAST C ITY H OSPITAL, Radiotherapy Department, Belfast, United
Kingdom
2
B ELFAST C ITY H OSPITAL, Medical Physics Department, Belfast, United
Kingdom
3
C ENTRE FOR C ANCER R ESEARCH & C ELL B IOLOGY, Q UEEN ’ S U NIVER SITY B ELFAST , Belfast, United Kingdom
1

Introduction: Total Skin Electron Beam Therapy (TSEBT) has been used formany years in the palliation of Cutaneous T Cell Lymphoma (CTCL) such as
Mycosis Fungoides. This rare condition often presents clinically with multiple
cutaneous lesions, severe itch and skin ulceration. The aim of the TSEBT
technique is to uniformly deliver a specified dose over the entire skin surface
to a depth of approx. 8mm to avoid penetration to bone marrow and other organs. The Northern Ireland Cancer Centre, Belfast is the only site that offers

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patients the TSEBT technique on the island of Ireland, with a total number of
36 patients treated since 1993. The aim of this review is to report the changes
to our technique in the past 4 years.
Methods: In March 2006, due to the transfer of clinical services, the TSEBT
technique was re-commissioned on 2 Varian 2100CD Linacs. The originalmodified version of the Stanford system consisted of 6 static fields which did
not fully comply with the EORTC guidelines published in 2002. The TSEBT
technique was changed to a dual angled beam Stanford system with 6 patient
positions per appointment and treatment delivered with 12 beams (2 beams
per field). This presentation will describe in detail the changes implemented
at the N.I. Cancer Centre, Belfast.
Results: In total 4 patients have been treated with the dual angled beam
Stanford technique since 2007, 1 patient died shortly after finishing treatment
and 3 are alive with disease.
The dose and fractionation has changed in line with the EORTC guidelines
from 20Gy in 10 fractions or 36 Gy in 18 fractions to 30Gy in 20 fractions over
5 weeks, treating 4 days per week. An in-house treatment stand has beendeveloped to raise the patient 20cms above the ground into the central partof the beam and to provide patient support. A 3mm Polycarbonate degrader
mounted on casters is placed in front of the patient stand during treatment toachieve the required beam energy.
Conclusions: The EORTC guidelines for TSEBT published in 2002 changed
our local clinical protocol in terms of dose, fractionation/overall treatment time,
QA procedures and treatment set-up. The dual angled beam Stanford technique in Belfast conforms to these guidelines in terms of beam characteristics,
uniformity and x-ray contamination levels.
73 speaker
IMMOBILISATION METHODS IN SARCOMA TREATMENTS
C. Dickie1
1
P RINCESS M ARGARET H OSPITAL, Radiation Technology, Toronto, Canada
Rarity of sarcoma in addition to heterogeneity of anatomic site provides
unique challenges in the management of this disease. Improvement in theaccuracy of immobilization methods parallels the advance of modern external beam radiotherapy approaches.
The objective of this lecture is to provide an overview of sarcoma immobilization methods from conventional radiotherapy to advanced practice, focusing
on common problems encountered while attempting to minimize set up uncertainty related to sarcoma treatment.
The treatment paradigm for sarcoma has evolved from conventional two or
three field techniques to highly conformal targeted therapy using online 3D
daily image guidance with evidence based error margins and dose objectives
for critical structure avoidance. Effective limb immobilization is an essential element of accurate and precise radiotherapy targeting. Immobilization
methods used within our institution have included sand bags, thermoplastic
moulds, polystyrene-filled cradles and an innovative custom device. Goals
for limb immobilization in the modern era should include patient comfort for
lengthy treatment and imaging procedures, limb stability in all cardinal directions, rotational reproducibility, reduction of the random and systematic set up
error, and user friendliness/durability for efficient workflow.
The development of patented inventions such as a versatile extremity immobilization device and a linear accelerator bed extension to accommodate
complex asymmetrical patient setups and variable anatomical tumour presentation will also be discussed.
74 speaker
AN OVERVIEW OF CSA RT; PAST, PRESENT AND FUTURE DEVELOPMENTS
H. Taylor1 , Y. Lee2 , J. Bedford2 , F. Saran3
1

T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiotherapy Dept.,
Sutton, United Kingdom
R OYAL M ARSDEN H OSPITAL T RUST & I NSTITUTE OF C ANCER R ESEARCH,
Physics Dept., London, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiotherapy Dept,
Sutton, United Kingdom
2This presentation will review the indications for Cranio-spinal Axis (CSA) RT
and then provide a brief history of the technique. It will concentrate predominantly on recent developments of a supine CT planned technique and thendiscuss novel techniques being studied or implemented currently. Their objectives are to decrease the acute side-effects and late effects of radiation
without reducing survival in both paediatric and adult CSA RT. A comfortable,
reproducible position for the patient is required, and an elegant solution to theinherent problem of matching fields and reducing dose to OAR such as theheart, thyroid and abdomen.Methods: Radiotherapy of the CSA is indicatedin primary tumours with a high propensity to spread through the CSF (e.g.
PNETs, ependymoma). Over the last 2 decades a reduction in dose to the
CSA has been possible due to the addition of adjuvant chemotherapy. Manygroups have looked at this with the Packer regimen being developed in themid 1990s reducing CSA dose to 23.4Gy for Standard risk disease. (Packer

M ONDAY, M AY 9, 2011
et al Treatment of children with medulloblastomas (MB) with reduced-dose
CSA RT and adjuvant chemotherapy: A CCG Study. J Clin Oncol. 1999
Jul;17(7):2127-36) The quality of the radiotherapy delivered may be a major
contributing factor to outcome and thus a technique which is able to verify
field matches, effect a moving gap and compensate for the inhomogeneity
involved in treating the entire length of the spine while being tolerable for thepatient is still a goal for some centres. Results: Conventional techniques
consisting of overlapped posterior photon fields, with boost fields to provide
additional dose homogeneity, conform poorly to the target volume. This isovercome with helical tomotherapy, although at the expense of a larger volume of normal tissue irradiated to a low dose (Parker et al. Standard andnonstandard craniospinal radiotherapy using helical TomoTherapy. Int J Radiat Oncol Biol Phys. 2010;77(3):926-3). Tomotherapy also eliminates theneed for matched fields. Proton therapy avoids irradiating large volumes ofthe patient to low dose, but still requires field matching (St. Clair et al. Advantage of protons compared to conventional X-ray or IMRT in the treatment of apediatric patient with MB. Int J Radiat Oncol Biol Phys. 2004;58(3):727-34).
VMAT offers a practical solution, based on a linac, which does not require
field matching (Lee et al. Development and evaluation of multiple isocentric
VMAT technique for CSA RT planning. Int J Radiat Oncol Biol Phys. in press).
Recent research towards helical VMAT also promises to provide a simple andefficient delivery solution.Conclusion: Crucially more centres delivering CSA
RT do so with a supine technique, and for those achieving this, improving accuracy, verification and reduced OAR dose is the next step. Patient comfort
and tolerability are much improved with the supine technique, but it is stillchallenging for some due to technical restrictions.

M ONDAY, M AY 9, 2011

Proffered paper
GEC Proffered Papers 1: Breast Cancer
75 oralTWELVE YEAR CLINICAL OUTCOMES WITH INTERSTITIAL ACCELERATED PARTIAL BREAST IRRADIATION
M. Wallace1 , C. Shah1 , C. Mitchell1 , W. John1 , F. Vicini1
1
W ILLIAM B EAUMONT H OSPITAL, Radiation Oncology, Royal Oak, USA
Purpose: To examine 12 year clinical outcomes in patients with early stage
breast cancer receiving adjuvant radiation therapy limited to the tumor bed(Accelerated Partial Breast Irradiation-APBI) utilizing interstitial catheters.
Materials: A total of 199 patients with invasive early-stage breast cancer
were prospectively treated at William Beaumont Hospital with APBI, receiving
interstitial brachytherapy to the tumor bed as part of their breast-conserving
therapy from October 1982 to November 2001. This included a total of 158
women who were prospectively enrolled on of one of three IRB approved
APBI protocols. Treatment techniques included a low-dose rate implant (LDR)
which delivered 50 Gy over 96 hours at 0.52 Gy/hr and a high-dose rate(HDR) implant that delivered either 32 Gy in 8 fractions BID or 34 Gy in 10
fractions BID. Clinical outcomes measured included local recurrence (LR) (ipsilateral breast tumor recurrence), regional recurrence (RR), distant metastases (DM), disease free survival (DFS), cause specific survival (CSS), andoverall survival (OS).
Results: The median follow up for the cohort was 10.7 years. Median age
was 65 years (range: 40-90 years) and median tumor size was 10 mm (range:
1-29 mm). With regards to receptor status, 86% of patients were estrogenreceptor positive, 69% progesterone-receptor positive, and 18% HER-2/neu
positive. Seventy nine patients (40%) received adjuvant hormonal therapy
while 25 patients (13%) received chemotherapy. Twenty three patients (12%)
were found to have N1 disease. Ninety seven percent of patients had negative margins and 3% had close margins (< 2mm). The 12 year rate of LR
was 5.0% while the rates of RR, and DM were 1.6% and 4.5% respectively.
DFS was 91% while CSS and OS were 95% and 71%. By ASTRO consensus
group, the rates of LR for the suitable (n=95), cautionary (n=63), and unsuitable (n=41) were 4.4%, 7.4%, and 2.5% (p=.64). Univariate analysis of LR
found that adjuvant hormonal therapy was a significant factor (p=.02) while
age, receptor status, tumor size, margin status, nodal status, chemotherapy,
and ASTRO consensus group were not.
Conclusions: With 12 year follow-up, clinical outcomes remain excellent withinterstitial APBI and compare favorably to traditional whole-breast techniques.
No differences in LR were seen based on the ASTRO consensus groups or
any other clinical factor.
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Conclusions: With median 72 month follow-up, Breast Conservation radiation therapy utilizing Interstitial Multi-Catheter HDR Implant has yielded local
recurrence rates and cosmetic results which compare favorably to EBRT in
selected patients. Treatment with anthracycline based Chemotherapy, large(> 200 cm3 ) implant volumes, and V-150% > 30%, appear to be relative contraindications to Interstitial HDR Implant. Finally, catheter spacing of 1 cm
yielded optimal dosimetry and minimized complications. Compared to Mammosite and Contura techniques, the Interstitial Multi-Catheter method offers
greater flexibility of radiation delivery. Advantages, include no concern regarding surgical cavity shape irregularities, balloon conformality to surgicalcavity, balloon rupture, balloon movement, air gaps, hematoma, seroma, skinballoon proximity to skin, balloon shape distortion, and catheter movement
within the balloon.
77 oral
MULTI-CATHETER
HIGH
DOSE
RATE
PARTIAL
BREAST
BRACHYTHERAPY: AN INNOVATIVE TECHNIQUE FOR CTBASED IMPLANT INSERTION AND PLANNING
H. Kader1 , W. Ansbacher2 , C. Popescu2 , Y. Pham2 , D. Nguyen1 , P. Truong1
1
BC C ANCER AGENCY, VANCOUVER I SLAND C ENTRE, Radiation Oncology, Victoria, Canada
2
BC C ANCER AGENCY, VANCOUVER I SLAND C ENTRE, Medical Physics,
Victoria, Canada
Purpose: To describe the details of an innovative CT-based, multi-catheter,high dose rate (HDR) interstitial brachytherapy technique, and to qualitatively
evaluate the resulting implants with reference to internationally recognizedbreast brachytherapy physics parameters.
Materials: Between May 2003 and December 2005, 30 patients, who had
undergone breast-conserving surgery for low-risk breast cancer, were treatedon a pilot study of adjuvant partial breast irradiation utilizing CT-based multicatheter HDR interstitial brachytherapy. All patients had pre-implant planning
CT scan with two specially fabricated radio-opaque grids, and corresponding breast skin marks, applied to the medial and lateral aspect of the breast.
An idealized virtual 3-D plan was created using ’BrachyVision’ software templates. Based on this plan, images of the medial and lateral aspects of thebreast were produced depicting the entrance and exit points of the catheters,
referenced to the medial and lateral grids initially marked on the breast (seefigure). Guided by these images, the HDR brachytherapy catheters were
subsequently inserted under conscious sedation and local anesthesia. The
patient then underwent post-insertion CT scan with the catheters in-situ; anda final treatment plan was created, delivering 32.4Gy (covering the 85% isodose line) in 9 BID fractions over 5 days, using an Iridium-192 HDR afterloading system. A retrospective analysis of dose-volume-histograms of thedelivered doses in all 30 patients was performed and referenced to thephysics parameters stipulated in the NSABP B-39/RTOG 0413 study.

INTERSTITIAL HIGH DOSE RATE BRACHYTHERAPY FOR EARLYSTAGE BREAST CANCER : MEDIAN 6 YEAR FOLLOW-UP OF 280
CASES USING MULTI-CATHETER TECHNIQUE
R. Lawrence1 , R. Mark2
1
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology and Nuclear Medicine, Lubbock, Texas, USA
2
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology and Medical Physics, Lubbock, Texas, USA
Purpose: External Beam Radiation Therapy (EBRT) has been the standardof care for breast conservation radiation therapy. Recent data indicates that
Interstitial Implant and High Dose Rate (HDR) radiation afterloading compares very favorably to EBRT in selected patients. We present our results in
280 patients treated with HDR using Multi-Catheter technique.
Materials: Patients with Tis, T1, and T2 tumors measuring < 4 cm, negative surgical margins, and < 3 axillary lymph nodes were judged to be candidates for Interstitial Implant. Implants were performed under Stereotactic
Mammographic guidance with conscious sedation and local anesthesia. The
implants were placed using the Anderson-Nair Template using from 3 to 8
planes, and 8 to 74 needles. Catheters were subsequently threaded thru theneedles, and the needles removed. Catheter spacing was 1.0 to 1.5 cm. Radiation Treatment planning was performed using CT Scanning and the Plato
System. Treatment volumes ranged from 25 cm3 to 359 cm3 . HDR treatment was given using the Nucletron afterloading system. The breast implant
volume received 3400 cGy in 10 fractions prescribed to the Planning Target
Volume, given BID over 5 days.
Results: Between 2000 and 2010, 280 patients underwent Interstitial HDR
Implant. The procedure was well tolerated. No patient required hospital admission. With a median follow-up 72 months (range 6-138 months), local
recurrence occurred in 4.3% (12/280). Cosmetic results were good to excellent in 89.6% (251/280) of the patients. There were no infections. Woundhealing complications developed in 2.9% (8/280). Three of these patients
had received anthracycline based Chemotherapy. The other five had large(> 200 cm3 ) implant volumes, catheter spacing of 1.5 cm, and V-150% of >30%. Two patients healed after 6 months of conservative treatment. Surgery
was required in six patients who developed fat necrosis.

Results: The Mean values (with B-39 criteria in brackets) were: %PTV90= 96% (>90%), V200 = 6cc (<20cc), V150 = 27cc (<70cc) and Dose Homogeneity Index (DHI) = 0.78 (>0.75). All parameters of individual implants werein compliance with these criteria with the exception of 5 cases in which DHI
was <0.75, reflecting the more stringent PTV coverage parameters used inthis pilot study.
Conclusions: The technique used in this study can be utilized to achieve
high quality interstitial multi-catheter breast brachytherapy implants without
the need for real time ultrasound guidance. A detailed illustrative descriptionof the technique will be presented.

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78 oral

80 oral

HIGH-DOSE RATE BRACHYTHERAPY AS AN AMBULATORY BOOSTTECHNIQUE IN BREAST CANCER : EXPERIENCE IN 502 PATIENTS
S. Rivera1 , N. Taright1 , L. Quero1 , C. Maylin1 , C. Hennequin1
1
H ÔPITAL S AINT-L OUIS, Department of Radiation Oncology, Paris, France

LOCALISATION OF THE SURGICAL CAVITY USING SUPINEMAGNETIC RESONANCE AND COMPUTED TOMOGRAPHY
SCAN FUSION FOR PLANIFICATION OF BREAST INTERSTITIAL
BRACHYTHERAPY
M. Jolicoeur1 , M. L. Racine1 , L. Hathout2 , S. David3 , I. Trop4
1
H OPITAL C HARLES L EMOYNE, Radiation Oncology, Longueuil, Canada
2
CHUM - C AMPUS N OTRE -DAME, radiation-oncology, Montréal, Canada
3
CHUM - C AMPUS N OTRE -DAME, Department of Medical Physics andRadiation Safety, Montréal, Canada
4
CHUM - C AMPUS N OTRE -DAME, Radiology, Montréal, Canada

Purpose: A boost dose is mandatory in most of the patients following irradiation of the mammary gland after lumpectomy. The best way to deliver
this boost dose is unknown: simplicity and efficiency are required. HDR
brachytherapy could be performed in one day under local anaesthesia.
Materials: Implant under local anaesthesia is performed early in the morning,
2 to 3 weeks after external beam irradiation (EBRT: 44 Gy). Verification films
and dosimetry (according to Paris’ system) are then immediately done, and afirst dose of 5 Gy is delivered usually 90 to 120 minutes after the beginningof the implant. A second dose of 5 Gy is delivered 4 to 6 hours later in theafternoon. The patient is going back home at the end of the day.Patients:
502 patients were treated between 1990 and 2003. Mean age was 58. Mean
histological size was 15 mm; most of the patients (80%) had an infiltrating
ductal carcinoma, the others having a lobular infiltrating carcinoma or a DCIS.
Surgical margins were negative in 66% of the cases, less than 2 mm in 24%
and positive in 4.8%.
Results: With a median follow-up of 5.5 years, 5-year local relapse rate is4.8%, most of the relapse occurring in the same area. Most of the relapse
occurs in the first four year of follow-up. The only prognostic factor of local
relapse in multivariate analysis was young age (≤ 40 years). Pathologicalstatus of margins was not significantly associated with local control. Half ofthe patients had a cosmetic evaluation with a satisfactory result in more than
80% of the cases. The main adverse effect was fibrosis in the brachytherapy
area.
Conclusions: In view of our results, HDR brachytherapy could be proposed
as an alternative to EBRT to boost the tumour bed. It could be performed in
one day under local anaesthesia in experienced hands.
79 oralA SAFE AND PREDICTABLE METHOD OF DELIVERING THERMALBOOST COMBINED WITH HDR BRACHYTHERAPY IN CONSERVATIVE MANAGEMENT OF BREAST CANCER
A. Chichel1 , J. Skowronek1 , M. Kanikowski1
1
G REATER P OLAND C ANCER C ENTRE, Brachytherapy Department, Poznan,
PolandPurpose: Standard breast conserving therapy (BCT) often uses interstitial multi-catheter HDR brachytherapy (BT) to minimize the risk of local relapse within the treated breast. Contemporary HDR BT offers conformal (CTbased), accurate and effective irradiation of the tumor bed. Nevertheless,there is still some place for further improvement in local recurrence rate. Additional local hyperthermia (HT), substantially used as an adjuvant therapy, isprobably one of the most effective radiation sensitizers known. HT (thermalboost) preceding standard BT boost has a potential of increasing the probability of local cure. The study is to report a new method of enhancing HDR
brachytherapy boost by interstitial microwave hyperthermia (MV HT, thermalboost) in conservative management (BCT) of early breast cancer.
Materials: Between February 2006 and December 2007, 57 stage IA-IIIA
breast cancer patients were treated with BCT ± adjuvant chemotherapy followed by 42,5 50 Gy whole breast irradiation (WBI) and 10 Gy HDR BT boost.
32 patients (56,1 %) were treated with additional pre-BT single session of interstitial MW HT to a tumor bed. Tiny microwave antennas were inserted into
the treated volume via brachytherapy applicators (multi-catheter technique,same implant for both treatments). Sets of planning CT scans provided strictgeometrical information about 3D orientation of applicators within the tumor
bed and enabled planning of the best pattern of MW antennas and thermometers to safely and efficiently heat the target volume before irradiation. Suchapproach enabled saving the skin and pectoral muscle form heating. Reference temperature was set on 43 C and intended therapeutic time (TT) was 1
hour. In addition, the incidence, severity and duration of early side effects ingroup with (I) or without hyperthermia (II) were assessed; significant p-value≤ 0,05.
Results: All 32 patients tolerated HT very well. HT sessions met the intended
requirements (median): reference temperature 42,2 C, therapeutic time (TT)61,4 minutes, total thermal dose 42 minutes and a gap between HT and BT 30
minutes. Median follow-up was 40 months with no local recurrences. GradeI and II radiodermatitis occurred in 24 (42,1 %) and 6 (10,5 %) patients, respectively, no significant difference between group I and II. Skin oedema anderythema occurred in 48 (85,7 %) and 36 (64,3 %) cases, respectively, bothwere equally distributed between the groups. Oedema was present up to 12
months and pattern of its regression was similar in group I and II, p = 0,933.
Conclusions: Combination of HT and standard HDR BT boost was feasible
and well tolerated. Pre-BT HT, having potential of improvement in breast
cancer loca, didn’t increase early toxicity in treated patients. All side effects
were transient and remained for up tol control 12 months. The study has to becontinued on a larger and randomized group of patients to verify the potentialof local control improvement and to assess the risk and profile of late toxicity.

Purpose: To evaluate the feasibility of a supine breast magnetic resonanceimaging (MRI) scanning for definition and localisation of the surgical bed after
breast conservative surgery
Materials: Patients were eligible for this study if they had conservative
surgery for breast cancer were candidates for brachytherapy as a component of their breast conservative treatment and had no contra-indications for
MRI. To ensure position reproducibility, patients were placed supine position
with ipsilateral arm above the head in an immobilization device. Localization
markers were placed around the nipple, on the sternal notch and on the skinalong the scar. All patients underwent planification CT and MRI exams in thesame implant/treatment position. The exam consisted in acquisitions of axial
and sagittal T1 and T2 images at 3-mm intervals. 4 points were predefinedfor CT-MRI image fusion. The surgical cavity was drawn on CT, then MRI,
separately by three independent observers. The MRI was a Siemens 1.5
Tesla with a body coil. Fusion and analysis of CT and MRI images was performed using the ECLIPSE treatment planning software. The surgical cavity
was drawn on CT, then MRI, separately by three independent observers.
Results: From September 2005 to November 2008, 70 patients were included in this prospective study. For each patients, we were able to acquire
axial T1 and T2 images of good quality. For image fusion, axial T2 images
were preferred. Using the predefined points the mean error following the fusion was 5.57 mm. Volumes obtained on MRI were respectively 30%, 38%
and 40% smaller than those determined from CT images for each observers.
There was a good correlation between the localization of the surgical bed on
MRI and CT with 85-95% of the MRI volume contained within the CT volume.
Inter-reader variability in the estimation of surgical bed volume was 10-32 %on both exams.
Conclusions: Supine breast MRI yields a more precise definition of the surgical bed than CT and obviate the need for surgical clips. The volume of thecavity is smaller with MRI. We propose that CT-MRI fusion to be use in thedelineation of the surgical cavity in view of partial breast irradiation
81 oral
BREAST TISSUE MODELING IN MONTE CARLO POST-IMPLANT
EVALUATION OF BREAST LDR BRACHYTHERAPY
H. Afsharpour1 , G. Landry2 , B. Reniers3 , J. P. Pignol4 , L. Beaulieu1 , F.
Verhaegen5
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Quebec, Canada
2
M AASTRICHT R ADIATION O NCOLOGY (MAASTRO CLINIC ), Maastricht,
Netherlands
3
MAASTRO CLINIC, Maastricht, Netherlands
4
O DETTE C ANCER C ENTRE , S UNNYBROOK H EALTH S CIENCES C ENTRE,
North York, Toronto, Canada
5
M AASTRICHT R ADIATION T HERAPY AND O NCOLOGY (MAASTRO) CLINIC,
Maastricht, Netherlands
Purpose: Breast tissue is mainly composed of glandular and adipose tissues.
The proportion of glandular/adipose tissue varies between patients depending on different factors such as the age of the patient. In the special caseof 103Pd LDR breast brachytherapy where low energy photons (21 keV) are
involved, the dose distribution is highly sensitive to chemical composition oftissues. Different approaches have been proposed to model the breast tissue for Monte Carlo dose calculations. The aim of this work is to use several
approaches to model the breast tissue and to compare their effect on postimplant dosimetry for a patient cohort treated with LDR brachytherapy.
Materials: Two months post-implant CT images of 35 breast LDR patientsalong with the contours of different organs are used to recreate accurate patient geometries in a Geant4.9.3-based Monte Carlo dosimetry platform. Different approaches are used to model the breast tissue. The first approach isbased on the TG43 recommendations for which all tissues are replaced by theunit-density water. The second approach uses water to create each voxel withits density assigned from the CT image. The third approach is to create thebreast tissue with a spatially uniform mixture of glandular/adipose with various proportions determined from the mean breast density. A fourth approach
uses a similar method but applies it voxel by voxel. Finally, a semi-automatic
segmentation approach is proposed using a density threshold distinguishing
the glandular from the adipose tissues inside the breast. To investigate theclinical impact, the D90 metric was extracted and compared between different
formalisms. It is important to note that the radiation transport is performed in

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the medium while the dose is scored in water.
Results: The 50-50 uniform breast model represents the highest dose to the
PTV and the lowest dose to the skin compared to the TG43 formalism, which
is predicting the lowest doses to the PTV. Looking at the DVHs for one patient(see the figure below), the D90 value is about 110 Gy in the 50-50 uniform
approach but it decreases to 98 Gy when the TG43 formalism is used. Using
the second approach (water with varying density) the same patient has a
D90 value of about 97 Gy which is very close to what is predicted by the
TG43 formalism. All tissue assignment approaches will be compared for 35
patients.

Conclusions: External validation of the nomogram shows adequate discrimination of AUR, but underestimation of the actual AUR risk. Since the nomogram is able to correctly identify low risk patients with a negative predictive
value of 98%, the nomogram can aid in individualized treatment decisionmaking.

Conclusions: Different tissue modeling schemes were used and comparedin this study. The resulting dose distributions and clinical metrics are quite
different when comparing these formalisms. This argues in favor of an agreement for a standard tissue modeling approach to be used everywhere in theclinics. Semiautomatic segmentation seems promising and feasible for moreaccurate dosimetry in LDR breast brachytherapy.

GEC Proffered Papers 2: Prostate Toxicity
82 oral
EXTERNAL VALIDATION OF THE PRE-TREATMENT NOMOGRAM TO PREDICT ACUTE URINARY RETENTION AFTER I-125
PROSTATE BRACHYTHERAPY
M. van Vulpen1 ,E. Roeloffzen1 ,E. Monninkhof2 ,S. Elantholi
Parameswaran3
1
U.M.C. U TRECHT, Radiation Oncology, Utrecht, Netherlands
2
U.M.C. U TRECHT, Epidemiology, Utrecht, Netherlands
3
P RINCESS M ARGARET H OSPITAL, Radiation Oncology, Toronto, Canada
Purpose: Acute urinary retention (AUR) after Iodine-125 (I-125) prostatebrachytherapy has a negative impact on quality of life. Recently, we developed a nomogram to preoperatively predict the risk of AUR. The aim of thisstudy was to assess the external validity of the nomogram.
Materials: The nomogram was initially developed on 714 patients treatedwith I-125 prostate brachytherapy at the University Medical Center Utrecht,
The Netherlands. Predictive factors included in the nomogram were prostate
volume, IPSS, neo-adjuvant hormonal treatment and prostate protrusion. For
external validation, the data of 715 consecutive patients who underwent I-125
prostate brachytherapy between January 2003 and July 2008 at the Princess
Margaret Hospital (PMH), Toronto were used. The performance of the nomogram was evaluated by discrimination (ability to distinguish between patients
who develop AUR yes or no) and calibration (agreement between observed
and predicted numbers of AUR).
Results: Of the 715 patients treated at the PMH, 67 patients (9.4%) developed AUR, compared to 8.0% in the UMCU cohort. In the validation dataset,the discriminatory ability of the nomogram was good (ROC area 0.86; 95% CI
0.82 0.91), and comparable to the derivation dataset (ROC area 0.82; 95% CI
0.77 0.88). Comparison between predicted risks and observed frequencies
of AUR showed systematic underestimation of the nomogram in the validation
dataset. Still, the negative predictive value for the risk of AUR, using a cut-off
value of 5%, was high (98.1%).

83 oral
URETHRA-SPARING, INTRA-OPERATIVE, REAL-TIME PLANNED,PERMANENT-SEED PROSTATE BRACHYTHERAPY: TOXICITYANALYSIS
T. Zilli1 , D. Taussky2 , D. Donath2 , P. L. Hoa3 , R. X. Larouche3 , D.
Béliveau-Nadeau3 , Y. Hervieux3 , G. Delouya3
1
C ENTRE HOSPITALIER DE L’U NIVERSITÉ DE M ONTRÉAL, Radiation
Oncology, Montreal, Canada
2
CHUM - C AMPUS N OTRE -DAME, Montréal, Canada
3
CHUM - C AMPUS N OTRE -DAME, Radiation Oncology, Montréal, Canada
Purpose: To report the toxicity outcome in patients with localized prostatecancer undergoing 125 I permanent-seed brachytherapy (BT) according to an
urethra-sparing, intra-operative (IO), real-time planned conformal technique.
Materials: Data were analyzed on 250 patients treated consecutively for lowor intermediate-risk prostate cancer between 2005 and 2009. The planned
goal was urethral V150 =0%. Acute and late genito-urinary (GU), gastrointestinal (GI) and erectile toxicities were scored with the International Prostate
Symptom Score (IPSS) questionnaire and Common Terminology Criteria for
Adverse Events (version 3.0). Median follow-up time for patients with at least
2 years of follow-up (n=130) was 34.4 months (range 24-56.9).
Results: Mean IO urethral V150, D5 and D2 were 0.018±0.08%, 193±24.3
Gy and 199±16.3 Gy, respectively. Mean prostate D90 and V100 on day30 computed tomography scan were 158.0±27.0 Gy and 92.1±7.2%, respectively. Low-activity sources (median activity 0.44 mCi, range 0.39-0.49)
were implanted in 113 (45.2%) patients, whereas 137 (54.8%) patients were
implanted with high-activity sources (median activity 0.61 mCi, range 0.540.68). Mean IPSS peak was 9.5±6.3 1 month after BT (mean difference
from baseline IPSS=5.3). The mean difference between baseline and postimplantation IPSS was 5.3 at 1 month, 4.6 at 4 months, 2.1 at 8 months,
and 0.5 at 12 months. 96.8% of the patients were receiving alpha-blockers
1 month after implantation, and this percentage decreased to 84.1%, 72.3%
and 57.3% at 4, 8 and 12 months, respectively. No acute GI toxicity was observed in 86.8% of patients. Overall, 31 (12.4%) and 2 patients presented
with acute Grade 1 and Grade 2 GI toxicity, respectively. The 3-year probability of Grade ≥2 late GU toxicity-free survival was 77.4±4.0%, with Grade
3 late GU toxicity encountered in only 3 patients( 3-year probability rate ofGrade ≥3 late GU toxicity-free survival of 97.5±1.9%) . Three-year Grade 1
late GI toxicity-free survival was 86.1±3.2%. No patient presented Grade ≥2late GI toxicity. At last follow-up, the rate of patients without erectile dysfunction decreased from 59.2% to 30.8%. 20.7% of patients with normal sexual
status at baseline manifested Grade ≥2 erectile dysfunction after BT. On multivariate analysis, elevated baseline IPSS (p=0.016) and high-activity sources(median 0.61 mCi) (p=0.033) predicted increased Grade ≥2 late GU toxicity.
Conclusions: Urethra-sparing IO BT is feasible and results in low acute andlate GU toxicity compared to the literature. High seed activity seems to increase the rate of mild to severe long-term urinary toxicity.

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84 oralDOSIMETRIC ANALYSIS OF URETHRAL STRICTURES FOLLOWING HDR MONOTHERAPY FOR ADENOCARCINOMA OF THE
PROSTATE
V. M. Mullassery1 , P. Diez2 , G. Lowe2 , P. Hoskin1
1

M OUNT V ERNON H OSPITAL, Radiotherapy and Oncology, Northwood
Middlesex, United Kingdom
2
M OUNT V ERNON H OSPITAL, Radiotherapy Physics, Northwood Middlesex,
United Kingdom
Purpose: To evaluate dosimetric parameters related to the development ofbrachytherapy induced urethral strictures in intermediate and high risk - adenocarcinoma of the prostate treated with high-dose rate brachytherapy as
monotherapy.
Materials: A total of 8 strictures were identified based on cystoscopic diagnosis from a cohort of 197 patients treated with high dose rate transperineal
ultrasound guided brachytherapy receiving either 34 Gy in four fractions, 36
Gy in four fractions, 31.5 Gy in 3 fractions or 26 Gy in 2 fractions. Treatment
plans incorporated strict tolerances for urethral D10 and D30. A matched pairanalysis was performed using 2 controls for each case of stricture within thesame fractionation schedule. Thus 16 controls were matched for dose fractionation schedule, pre-treatment IPSS score, number of needles used for
insertion and CTV volume. The urethra was divided into prostatic urethra andmembranous urethra for the purpose of analysis. The prostatic urethra wasdivided further into upper, mid and lower third. Dosimetric parameters wereanalysed for all outlined volumes. Mann-Whitney and Chi-squared statisticaltests were used to evaluate any differences between cases and controls.
Results: There was one stricture in the 34 Gy (3%) group, one in the 36 Gy(4%) group and the other six were in the 31.5 Gy group (6%). As the medianfollow up for the group receiving 26Gy in 2 fractions was only 6 months they
were excluded from the analysis. The median time to stricture formation was
23 months (range 5 and 40 months). The urethral V10, V8.5, D10, D30, Dmax
and mean doses were analysed using Mann-Whitney test and found not to
be statistically different between cases and controls (p values ranging from
0.198 to 1.000 for 95% confidence). Chi-squared test showed no correlation
between stricture rates in the different fractionation schedules.
Conclusions: There was no significant difference in stricture rates between
schedules. No correlation was seen between any of the dosimetric parameters analysed and strictures when compared to matched case controls.

M ONDAY, M AY 9, 2011
comparable to LDR implant. Previous TURP is not a contraindication to HDR
implant for prostate cancer.
86 oralOBJECTIVE BASELINE PARAMETERS INFLUENCE ON URINARY
SIDE EFFECTS AFTER BRACHYTHERAPY OF THE PROSTATE
T. de Vries1 , H. de Jager - Nowak1 , M. Kiewiet de Jonge2 , M. Mast1 , H.
Struikmans1
1
R ADIOTHERAPY C ENTRE W EST, The Hague, Netherlands
2
H AGA Z IEKENHUIS L OCATIE L EYENBURG, Urology, Den Haag, Netherlands

M ONDAY, M AY 9, 2011
years versus 65 years in HDR BRT subgroup (p=0.044). The prostate volume
was larger in IMRT group (median 28.7 vs. 22.5ccm, p=0.0001). Input IPSS
was higher in IMRT group (10 vs. 5). Acute GU toxicity was significantly
higher in IMRT group (p=0.002). The biggest difference we found in grade
2 GU toxicity (fig. 1). The effect of pretreatment IPSS, prostate volume or
the age wasn’t observed. Also acute GIT toxicity was finded as significantly
higher in the group with IMRT (p=2.6x10-12 ). Again the biggest difference wasrecorded in grade 2 GIT toxicity (fig. 2). G3 toxicity wasn’t noted in HDR BRT
arm at all, in IMRT arm was very low.

Purpose: I-125 prostate brachytherapy (PB) shows excellent tumor control
and survival rates in early stage prostate cancer. Hence, toxicity is considered also an important endpoint. Acute urinary retention (AUR) requiring
catheterization, sometimes followed by transurethral resection of the prostate(TURP), has a negative impact on quality of life. The main purpose of thisstudy was to determine if the objectively determined parameters such as urinary flow and residual volume after voiding could help to select patients who
are at high risk for AUR and/or TURP.
Materials: The relevant data were retrieved from a single centre prospective database containing both low and medium risk prostate cancer patientstreated with I-125 PB from 2000 2008. Pretreatment and follow-up maximum urinary flow, post-void residual volume (PVRV), AUR, TURP were documented.For analysis of continuous variables results were analyzed by a ttest. Some variables were transformed to dichotomous variables. To compare
these variables, a chi-square test was used.
Results: A total of 337 patients, with early stage prostate cancer, were analyzed. The mean age was 65 years.For 83 patients urinary flow before PB andfor 213 patients PVRV before PB was measured. Thirty-one (9,2%) patients
had AUR and 34 (10,1%) underwent TURP. Our results show that in the groupof patients with a prostate volume ≥30 cc, more patients developed AUR andunderwent a TURP more frequent than in the group of patients with a prostate
volume <30 cc. Most patients with an urinary flow ≥15 ml/s 3 months after
PB preserved this flow after 9 months. In the group of patients with an urinary flow <15 ml/s before PB more patients developed AUR compared withthe group of patients having an urinary flow ≥15 ml/s. In the group of patients with a PVRV ≥50 cc more patients underwent a TURP compared withthe group of patients having a PVRV <50 cc. The majority of all the TURP
procedures were performed between 6 and 12 months after PB.

85 oralPREVIOUS TRANSURETHRAL RESECTION OF THE PROSTATE(TURP) IS NOT A CONTRAINDICATION FOR INTERSTITIAL HIGHDOSE RATE (HDR) BRACHYTHERAPY FOR PROSTATE CANCER
C. Johansen1 , R. Mark1 , R. Akins1 , M. Nair1
1
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, USA
Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for
prostate cancer using Low Dose Rate (LDR) and High Dose Rate (HDR)
technique has been reported with results comparing favorably to surgery andExternal Beam Radiation Therapy (EBRT). Previous TURP has been considered a relative contraindication for LDR permanent seed implant because ofhigher rates of urinary incontinence. There is little data on previous TURP
and subsequent incontinence after HDR implant. We report our urinary incontinence results with HDR with or without previous TURP.
Materials: Between 1997 and 2010, 428 patients with T1 and T2 localized
prostate underwent TRUS guided interstitial implant. There were no Gleason
Score or PSA exclusions. After discussion of treatment options, 109 patients
elected HDR Implant + IMRT and 319 patients underwent HDR monotherapy.
No patient received Hormonal Blockade. Median Gleason Score was 7 (range: 4 to 10). Median PSA was 9.8 (0.60 to 39.8). IMRT treatment volume
included the prostate + seminal vesicles + 2 cm margin. Implant treatment
volumes ranged from 32 cm3 to 196 cm3 . In patients who received IMRT +HDR, 4500 cGy in 25 fractions was given via IMRT and 1650 cGy to 2000 cGy
in 3 fractions via HDR. Our protocol for HDR alone, has called for two HDR
Implants. The treatment volume received 2,250 cGy in 3 fractions prescribedto the 100% Isodose line, given over 24 hours. A 2nd implant was performed
4 weeks later, delivering a further 2,250 cGy in 3 fractions, bringing the final
dose to the prostate to 4,500 cGy in 6 fractions. Urethral dose points (12-16)
were followed, and limited to < 105% of the prescription dose. Care was also
taken to limit dose to the bladder sphincter regions.
Results: There was no significant difference between the treatment groups
with respect to T-Stage, Gleason Score, and PSA. With a median follow-up
of 102 months (range : 6 months to 174 months), urinary stress incontinence
has occurred in 2.8% (12/428). Previous TURP was performed in 65 patients.
Incontinence has developed in 3.1% (2/65) undergoing previous TURP vs.
2.8% (10/363) in the non-TURP group (p=0.70). RTOG late bladder toxicities
were : 0% Grade 4, 0% Grade 3, and 2.8% (12/428) Grade 2. Urinary stressincontinence has occurred in 2.8% (9/319), undergoing HDR alone, vs. 2.8%
(3/109) treated with HDR + IMRT (p=0.74).
Conclusions: Urinary stress incontinence after HDR implant occurs in rates

Conclusions: Patients with an urinary flow ≥15 ml/s 3 months after PB could
be discharged of the urinary flow follow-up at 9 months after PB.Prostate
volume and urinary flow are potentially suitable as variables predicting for
AUR after PB. Whereas prostate volume and PVRV may predict the necessityof a TURP after PB. Further research has to be done with a larger group ofpatients.
87 oralDOSE ESCALATION WITH IMRT TECHNIQUE VERSUS IMRT +HDR BRT IN PATIENTS WITH HIGH RISK CARCINOMA OF THE
PROSTATE – COMPARISON OF ACUTE TOXICITY
R. Soumarova1
1
O NCOLOGICAL C ENTER N OVÝ J I ČÍN, Radiation Oncology Department,Nový Jičín, Czech Republic
Purpose: Radiotherapy (RT) in combination with hormonal therapy (HT) is
standard treatment option in high risk prostate cancer patients. Elective treatment of the pelvic lymph nodes in this subgroup of prostate patiens might
improve disease-free survival. A dose escalation to the prostate is possible
to provide intensity-modulated RT (IMRT) or high-dose rate brachytherapy(HDR BRT) technique.
Materials: We compared two subgroups of high risk patients (T3, GS 8- 10
or PSA > 20). The both groups underwent pelvic RT using IMRT technique(4550,4Gy in 25-28 fractions) and neoadjuvant HT 3-4 months prior RT, concomitant HT together with RT and adjuvant HT. The dose escalation was
performed using IMRT 26Gy in 13 fractions in the first subgroup or 16Gy in
2 fractions to the reference isodose in HDR BRT subgroup. Acute toxicity
scores were recorded weekly during RT and in 3 month interval post-RT using RTOG acute toxicity scales.
Results: 125 patients with a histological diagnosis were enrolled, 83 in thegroup with IMRT, 42 in the group with HDR BRT. Follow-up median was 18
months. Patients in IMRT subgroup were older in general, median age 68

Conclusions: We recorded a very good therapy toleration in both study
arms. Pelvic IMRT with boost to the prostate was well tolerated in this series,
with low rates of Grade 3 orgreater acute toxicity. Pelvic lymphatic nodes RT
in combination with HDR BRT dose escalation caused acute toxicity of minimal degree. To evaluate late toxicity and biochemical failure we need longer
follow-up interval/period. Longer follow-up for outcome and late toxicity isrequired.
88 oral
PREDICTORS FOR PERSISTENT OBSTRUCTIVE URINARY SYMPTOMS REQUIRING A TURP AFTER BRACHYTHERAPY OF THE
PROSTATE
M. Steggerda1 , T. Witteveen1 , H. van der Poel2 , L. Moonen1
1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Urology, Amsterdam, Netherlands

Purpose: Urinary toxic reactions after brachytherapy of the prostate with
I-125 seeds are mostly temporary symptoms that will gradually disappear
within a few weeks to a few months after the implantation procedure. However, in a relatively small number of cases obstructive symptoms persist anda transurethral resection of the prostate (TURP) is required to regain normal
urinary functioning. The purpose of this study was to investigate possible
relations between persistent obstructive urinary symptoms and physical parameters of I-125 permanent implants.
Materials: In the period between 2002 and 2010, 321 patients with low to intermediate risk prostate cancer were treated with I-125 seeds with an activity

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S 33

of 0.45±0.03 mCi. The prescribed dose was 145 Gy. 14 patients (4.4 %)underwent a TURP procedure to resolve persistent obstructions. The mediantime interval between implantation and TURP was 14 months (range 6-43
months). Dose volume histograms (DVHs) of the prostate, the urethra andthe bladder wall were calculated based on a combined TRUS-CT scan madeone day after the implantation. Several cut-off points of these DVHs andsome other physical parameters were used for statistical analysis. KaplanMeier diagrams, stratifying between ≤median and >median values, and Cox
regression analyses were used to identify predictors for persistent obstructive
symptoms requiring a TURP.
Results: Significant differences were found in "free of TURP" Kaplan-Meierdiagrams distinguishing between prostate volumes of ≤41 cm3 and >41 cm3(p=0.004) and dose to the "hotspot" 1cm3 of the bladder (D1cc-bl) of ≤131
Gy and >131 Gy (p=0.025). Of the 14 TURP cases, 12 had a prostate volume> 41 cm3 and 11 had a D1cc-bl > 131 Gy. After multi-variate Cox regression
analysis the prostate volume and D1cc-bl were the only independent significant predictors (p=0.017 and p=0.042 resp.). Prostate and urethra DVH parameters were not significantly related with TURP.
Conclusions: In a previous study a significant relation was found between
prostate volume as well as bladder hotspot dose and urinary morbidity 3 and6 months after the implantation procedure. In this study we found the same
predictors for persistent urinary obstructions requiring a TURP. We have toconclude that the bladder is an "organ at risk" for prostate brachytherapy (especially in combination with a large prostate) and that sparing the bladdershould be an important issue during the planning and implantation procedure.

S 34

S YMPOSIUM

Symposium
Head & Neck cancer - Vision for the future: What‘we’ will ask for in the new grant applications? Biological and image guided adaptive radiotherapy
89 speaker
UNDERSTANDING AND TAKING ADVANTAGE OF THE TUMORBIOLOGY
R. Brakenhoff
Abstract not received.

90 speaker
LOCALIZE THE ENEMY: IMAGING IN H&N CANCER
V. Grégoire
Abstract not received.

91 speaker
ADAPTIVE RADIATION TREATMENT OF HEAD AND NECK CANCER
IN THE FUTURE – ADVANCED TREATMENT PLANNING AND
DELIVERY
C. Grau1
1
A ARHUS U NIVERSITY H OSPITAL, Aarhus C, Denmark

M ONDAY, M AY 9, 2011
specifically target and inhibit proteins that are of importance for the tumor
growth and survival.
Non-invasive assessment of the response of the tumor to preoperative CRT
is essential for further selection of patients who could be spared invasive
surgery. The usefulness of molecular markers present in the tumor tissue
and blood of the patients and of non invasive imaging techniques such as(Diffusion-Weighted (DW-)MRI and 18-F Fluoro-deoxyglucose positron emission tomography (18FDG-PET) needs careful study.
Strong evidence has emerged indicating that changes in 18FDG uptake,measured by the standardized uptake value (SUV) appear to be a valid predictive factor for outcome (Capirci C et al. Biomed Pharmacother 2004;
Capirci C et al. Eur J Nucl Med Mol Imaging 2007; Janssen MH et al. Int
J Radiat Oncol Biol Phys 2010; Capirci C et al. Int J Radiat Oncol Biol Phys2009). These results were recently confirmed by results on 20 patients at ourcentre (Lambrecht M et al. Acta Oncol 2010).
While conventional MRI lacks functional information, DW-MRI has overcome
these shortcomings and provides functional information of the tumor microenvironment (Koh DM, et al. Am J Roentgenol 2007). DW-MRI has proven its
value in head and neck squamous cell carcinoma (Vandecaveye V et al. Int J
Radiat Oncol Biol Phys 2007). Preliminary results in our centre showed that
DWI is more accurate for early response prediction than volumetric measurements and can be used to estimate 2-year locoregional control and disease
free survival in head and neck cancer (Vandecaveye V et al. Eur Radiol 2010).
This implies that DW-MRI might be able to predict tumor response early. Patients with a good response to treatment generally show a lower ADC prior
to treatment and with a higher ∆ADC during and after chemoradiation. The
hypothesis is that a low initial ADC value represents a more restrictive environment with less interstitial edema, necrosis and a higher cellularity. This
necrosis is generally associated with an acidic environment and a low oxygen
concentration which influences the response to radiotherapy and chemotherapy.

Abstract not received.

ESTRO-ESSO Joint Symposium: Vision for the future: What ‘we’ will ask for in the new grant applications? - Translational research / High technology
92 speaker
ADAPTIVE RADIOTHERAPY IN RECTAL CANCER: FUTURE OR
FUTILE?
C. Marijnen1
1

M ONDAY, M AY 9, 2011

Proffered paper
Physics Proffered Papers 1: Response Prediction:
Geometry and Precision
95 oral
ADAPTATION OF RADIOTHERAPY TO A SHRINKING MACROSCOPIC TUMOR IN ADVANCED STAGE NSCLC DOES NOTUNDERDOSE THE MICROSCOPIC DISEASE AND HAS THE POTENTIAL TO INCREASE TUMOR CONTROL PROBABILITY
M. Guckenberger1 , A. Richter1 , J. Wilbert1 , M. Flentje1 , M. Partridge2
1

U NIVERSITY H OSPITAL W UERZBURG, Department of Radiation Oncology,
Wuerzburg, Germany
2
I NSTITUTE OF C ANCER R ESEARCH, Sutton, United Kingdom

Purpose: Substantial tumor regression has been described in conventionallyfractionated radio(chemo)therapy for advanced stage NSCLC. It was the purpose of this study to evaluate whether adaptation of radiotherapy (ART) toa shrinking gross tumor volume (GTV) bears the risk of underdosage of the
microscopic disease (MD) and whether iso-toxic dose escalation using ART
could increase tumor control probability (TCP).
Materials: For analysis of tumor regression and simulation of ART, weekly
spiral CT images were acquired for 13 patients treated with conventionally fractionated radiochemotherapy for locally advanced NSCLC. Threedimensional conformal radiotherapy plans were generated based on the planning CT with total doses of 66Gy prescribed to the planning target volume(PTV); treatment plans were adapted to GTV shrinkage once (in week 3 or
5) or twice (in week 3 & 5) during radiotherapy; doses in the ART plans were
escalated using an iso-toxic mean lung dose (MLD) based approach. Dose
distributions to the volumes of suspected MD were simulated for a scenario
with synchronous shrinkage of the MD and GTV and for a scenario of a stationary MD despite GTV shrinkage; simulations and dose accumulation were
performed using deformable image registration. TCP calculations considering doses to the GTV and MD were performed using three different models.
Results: Coverage of the MD at 50Gy was not compromised by ART. Coverage at 60Gy in the scenario of a stationary MD was significantly reduced from
92%±10% to 73%±19% using ART; however, the coverage was restoredby iso-MLD dose escalation. Dose distributions in the MD were sufficientto achieve a TCP >80% on average in all simulation experiments, with theclonogenic cell density the major factor influencing TCP. The combined TCP
for the GTV and MD was 19.9% averaged over all patients and TCP models. Iso-toxic dose escalation achieved by ART increased the overall TCP byabsolute 6% (adapting plan once) and by 8.7% (adapting plan twice) on average with large inter-patient variability. Absolute TCP values were significantly
different between the TCP models; however, all TCP models suggested very
similar TCP increase by using ART.

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96 oralTHE IMPACT OF MICROSCOPIC DISEASE ON THE TCP IN NSCLC
C. Siedschlag1 , L. Boersma2 , J. Van Loon2 , M. Rossi1 , A. van Baardwijk2 ,K. Gilhuijs3 , J. Stroom1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiotherapy, Amsterdam, Netherlands
2
MAASTRO CLINIC, Maastricht, Netherlands
3
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiology, Amsterdam, Netherlands
Purpose: to establish the CTV margin required for an adequate treatmentof non-small-cell lung cancer (NSCLC) using either 3D conformal radiotherapy (CRT) or stereotactic radiotherapy (SRT), taking the distribution of the
microscopic disease extension (MDE) into account.
Materials: Previously measured distributions of MDE outside the macroscopic tumor in NSCLC patients were used [1]. The distributions of systematic and random geometrical errors (including delineation uncertainty) weretaken from our clinic (Σ=σ =3mm and Σ=σ =4mm for SRT and CRT, respectively). Then, a PTV margin was added [2] to a spherical GTV with 4 cm diameter, and dose distributions typical for CRT (24x2.75Gy) and SRT (3x18Gy)
were simulated. Finally, Monte-Carlo simulations in 200 patients were performed to study the combined impact of MDE and geometrical uncertainties
on the tumor control probability (TCP), based of the linear-quadratic biological model. The dependence of the TCP on the clinical target volume (CTV)
margins was quantified.
Results: In about 50% of NSCLC patients MDE was found, up to 4 cm fromthe GTV [1]. The presence of MDE had a demonstratable influence on the
TCP in both CRT and SRT when no CTV margins were employed. The impact
of MDE on the TCP values was greater for CRT (61 % and 83 % TCP with andwithout MDE, respectively) than for SRT (84 % and 100 % TCP, respectively).
Looking in more detail at patients with MDE, all TCP failures for SRT occur
outside the main tumor (at distances between 15 and 35 mm from the GTV),
whereas for CRT failures can occur also inside the GTV (near the edge) andoutside the GTV the range with failures is larger (between 10 and 40 mm fromthe GTV). An increase of the CTV margin had the greatest impact for the CRT
technique (see Figure). Different setup errors, when properly accounted forin the PTV margin, lead to differences in TCP for both techniques, showing
the interdependence of CTV and PTV margins.

L EIDEN U NIVERSITY M EDICAL C ENTER, Leiden, Netherlands

Abstract not received.
94 speaker
93 speaker
ADAPTIVE RADIOTHERAPY BY MOLECULAR IMAGING CHANGESK. Haustermans1
1
L EUVENS K ANKER I NSTITUUT (LKI), U NIVERSITY H OSPITAL G ASTHUIS BERG , Radiation Oncology, Leuven, Belgium
Rectal cancer is a frequent and curable malignancy in the Western world.
The introduction of the total mesorectal excision (TME) with its wider lateral
margins reduced the number of locoregional recurrences drastically [MacFarlane, 1993; Kapiteijn 2001]. Preoperative radiotherapy has proven its worth inreducing local control rates and overall survival in all stages of rectal cancer[Kapiteijn 2001], which was further increased by the addition of fluorouracil
based chemotherapy schedules [Sauer 2004]. Besides the increased local
control rate, chemoradiation (CRT) has the additional advantage of inducing
a significant tumor downsizing and even downstaging [Bosset, 2005; Valentini, 2001]. In 10-30% of the patients no residual tumor tissue after CRT canbe observed. These patients have a favorable long term outcome.
Currently, the standard therapy for each patient is preoperative treatment followed by extensive surgery regardless of the tumor response.
However, the last decade the question arose whether extensive surgery can
be avoided and replaced by minimal invasive surgery or no surgery at all forpatients with a pathologic complete response (pCR) without compromisingtumor control [Habr-Gama, 2004]. To date however, the only way to ascertain pCR is pathologic examination of the resection specimen. In contrast
with the patient group with a good prognosis, for which (invasive) surgery
could be omitted, patients with ’ugly’ tumors could benefit from a more intensified treatment by addition of molecular targeted drugs. Therefore, standard(chemo)radiotherapy can be combined with molecular targeted agents that

ADAPTIVE RADIOTHERAPY BY PREDICTIVE BIOLOGICAL MARKERS
C. Rödel1
1
K LINIKUM DER J OHANN W OLFGANG G OETHE U NIVERSITÄT, Department ofRadiotherapy Oncology, Frankfurt, Germany
The rapidly increasing knowledge of the molecular basis and pathways that
influence and modify radiation response has led to the identification of biological markers that may help to predict responsiveness to radiotherapy
or combined modality treatments. Such biomarkers and molecular signatures may be investigated using high-throughput technologies (genomics,
transcriptomics, proteomics) with the aim to fully implement patient-specific"biological stratification" of radiation treatments. Within the next decade, it
should be possible to combine such information with advanced delivery technologies to design biologically adapted radiation therapy, e.g. radiation dose
escalation to more radioresistant regions within the tumor. Changes in tumor
and normal tissue biology during early treatment may also be predictive of tumor response and adaptive strategies during treatment may help to optimize
outcomes. Moreover, these molecular structures can be specifically targetedby modern anticancer drug development with the aim of overcoming radioresistance of tumor cells or protecting normal tissues. Promising modifiers ofradiation response are now entering early clinical trials. Stratification basedon classical parameters plus predictive biological markers is required to fully
exploit the potential of innovative molecular drugs for improving radiotherapy.

Conclusions: Adaptation of radiotherapy to the shrinking GTV did not compromise dose coverage of volumes of suspected microscopic disease andhas the potential to increase TCP by >40% compared to radiotherapy planning without ART.

Conclusions: this modeling illustrates that microscopic disease is not always
eradicated by the beam penumbra using either 3D conformal or stereotactic
radiotherapy. Nonetheless, TCP modeling indicates an overall local control
rate above 90% for the stereotactic technique, so the penumbra takes careof most MDE. For 3D conformal RT, however, a non-zero CTV margin would
yield a relevant improvement in local control of MDE.References:[1] van Loon
J/Siedschlag C, Stroom J et al., Int J Radiat Oncol Biol Phys 2010 [Epubahead of print].[2] Van Herk M, Remeijer P, Rasch C et al. Int J Radiat Oncol
Biol Phys 2000;47:1121-1135.

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M ONDAY, M AY 9, 2011

97 oral98 oralTCP LOSS DUE TO SETUP ERRORS AS A FUNCTION OF DOSERESPONSE SLOPE AND NUMBER OF FRACTIONS
J. Selvaraj1 2 , J. Uzan1 , C. Baker1 , A. E. Nahum1

QUANTITATIVE PARAMETERS OF PAROTID DEFORMATION ARE
HIGHLY CORRELATED TO DVH: EVIDENCE OF A DOSE-BATH
EFFECT AROUND 15GY
S. Broggi1 , E. Maggiulli1 , C. Fiorino1 , I. Dell’Oca2 , G. Sanguineti3 , W.

1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics, Bebington, Merseyside, United Kingdom
2
U NIVERSITY OF L IVERPOOL, School of Health Sciences, Liverpool, United
Kingdom

Purpose: Development of flexible software to study the effect of CTV-PTV
margin size on the population TCP for different fractionation and doseresponse curves (DRCs).
Materials: A program has been developed which calculates the total dose,
fraction by fraction, to each voxel in the target volume for a given standard
deviation of systematic and random errors.TCP is calculated using the "Marsden" model. A spherical dose distribution is generated by convolving a spherewith a 3D Gaussian kernel (3.2 mm SD) to mimic a conformal plan. A CTV of
25mm radius and PTVs defined by margin sizes of 3, 4, 6, 7, 9, 12mm weregenerated. In all cases, the 95% isodose just encompasses the PTVTo study
the effect of fractionation regimes on TCP with different CTV-PTV margins,systematic and random (inter-fraction) errors were sampled from a Gaussian
distribution: 3000 ’treatments’ were simulated for each of the fractionation
regimens (3,10,20,30 fractions). A prescription dose of 55Gy in 20 fractions
was used as reference, and total dose was rescaled for all other regimes sothey all result in 50% TCP for a static tumour. Overall treatment dose wassummed over each fraction, by applying a transformation to each voxel inside the CTV using the error values generated for each fraction. From thesesummed dose distributions, DVHs were calculated using a uniform sampling
method with grid resolution of 1x1x1 mm3 .TCP parameters were α=0.30,
α/β =10, σα =0.048, 0.07, 0.2185 (steep, typical, shallow DRCs), ρcl =107
cm-3 . Mean (population) TCP, D95% to the CTV and the proportion of patients for whom TCP falls by 1% or less were calculated. Tumour repopulation
effects were excluded.
Results: Mean TCP for σα =0.07 ranged from 37.6 to 43.6, 42.6 to 46.8,
47.9 to 49.2, 49.1 to 49.6, 49.76 to 49.9 and 50.0 to 50.0 for 3,4,6,7,9,12mm margins respectively with fraction sizes ranging from 3 to 30 fractions(see figure). Mean TCP for σα =0.048 ranged from 35.02 to 41.65, 41.13
to 45.20, 47.15 to 48.80, 48.70 to 49.42, 49.69 to 49.86 and 49.98 to 50.0
for 3,4,6,7,9,12 mm margins respectively with fraction sizes ranging from 3 to30 fractions. Similarly for σα =0.2185, the mean TCP ranged form 43.27 to
46.82, 46.23 to 48.40, 49.00 to 49.56, 49.40 to 49.83, 49.88 to 49.96, and50.00 to 50.00.

Binbin3 , E. Scalco4 5 , G. M. Cattaneo1 , N. Di Muzio2 , G. Rizzo67 , R.
Calandrino1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Radiotherapy, Milan, Italy
3
J OHN H OPKINS H OSPITAL, Radiotherapy, Baltimore MD, USA
4
I STITUTO DI B IOIMMAGINI E F ISIOLOGIA M OLECOLARE, Segrate (Milan),
Italy
5
U NIVERSITY OF M ILANO -B ICOCCA, Fondazione TECNOMED, Milano, Italy
6
I STITUTO DI B IOIMMAGINI E F ISIOLOGIA M OLECOLARE , CNR, Segrate(Milano), Italy
7
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Nuclear MedicinePET-TC, Milan, Italy
Purpose: The jacobian of the deformation field of elastic registration between
images taken during RT is a measure of compression/expansion of the voxels
within an organ. The histogram of the jacobian values within an OAR (JVH)
was introduced and applied to quantify parotid shrinkage. The correlations
between JVH and planning DVHs were investigatedMaterials: Two groups of patients with HN cancer were separately considered:32 patients treated with Helical Tomotherapy unit (group 1) and 22 withconventional Linac IMRT (group 2). Parotid deformation was evaluated trough
MVCT/KVCT images taken at the start and at the end of the treatment. Jac
was calculated for each voxel of all parotids and integral JVHs were calculated for each parotid gland. The correlation between JVH and planning DVH
was first investigated in group 1; the consistence of the results was then independently verified in group 2.
Results: For group 1, on average 82% (± 17 %) of the voxels shrinks (Jac<1)
and 14% (± 18 %) shows a local compression >50% (Jac0.5), with a medianvalue of 7.2%. For group 2 an average of 84% (± 13 %) of the voxels showeda Jac<1 and 15.4% (± 14 %) was the average Jac0.5. A larger median valueof 13.9% was found for Jac0.5. For group 1 the best correlation between
DVH and JVH was found between V10-V15 and Jac0.4-0.6. (p<0.01). The
best constraint predicting a reduced number of largely compressing voxels(Jac0.5<7.5%, median value) was V15<75% (OR:7.6; p=0.002). V15<75%
was consistently found well correlated to Jac0.5 also in group 2 (p=0.013).
Moreover, when pooling the two groups, V15<75% strongly predicted therisk of having a Jac0.5 larger than the median value of the whole population(Jac0.5>10%, OR: 5.96; p=0.0001).
Conclusions: Quantitative assessment of parotid deformation during RT
may be represented in terms of Jac and JVH. Our analysis shows that thepattern of deformation may be well predicted by the shape of the planned
dose distribution. In particular, a dose bath around V15 to most part of thegland is the most important predictor.
99 oral
APPROACHING THE ‘TRUE’ DVH TO IMPROVE PREDICTION OF
TOXICITY - A RECTAL MOTION SIMULATION STUDY
M. Thor1 23 4 , A. Apte4 , J. O. Deasy4 , L. P. Muren1 23
1
C LINICAL I NSTITUTE, Aarhus University, Aarhus, Denmark
2
D EPARTMENT OF M EDICAL P HYSICS, Aarhus University hospital, Aarhus,
Denmark
3
D EPARTMENT OF O NCOLOGY, Aarhus University hospital, Aarhus ,Denmark
4
D EPARTMENT OF M EDICAL P HYSICS, Memorial Sloan-Kettering Cancer
Center, New York, USA

Conclusions: For the steep DRC with g = 2.8, margins of 8.2mm and 7mm
result in a 1% TCPpop loss for 3 and 30 fractions resp. For shallow DRC withg = 0.2185, 6.6mm and 5.8mm results in a 1% TCPpop loss. It is evident thateven for a steep dose-response curve smaller margins than those from the
VanHerk recipe (van Herk et al, IJROBP,2000, 47:112135) could be applied
whilst still maintaining <1% TCP loss relative to the static tumour case.

Purpose: The rectum exhibits substantial organ motion throughout thecourse of radiotherapy (RT) for pelvic tumour sites. The motion causes uncertainties in the dose delivered to the rectum and is likely to influence on
the probability of developing rectal toxicity. In this study, simulations of rectal
motion is introduced for the purpose of predicting late rectal toxicity in comparison with use of the static rectum only from the planning CT.
Materials: Late rectal toxicity was defined as late gastro-intestinal (GI) toxicity according to the RTOG scoring system in 232 prostate cancer patientspreviously treated to 70 Gy with conformal RT. Random translational rectal
motion described by normal distributions (in 3D) with isotropic shifts i.e. standard deviations of 0.1-1.0 cm were repeatedly applied (1, 5, 10 and 20 trials)
to the static rectum of each patient over their 35 fractions. Average DVHs
based on the trial simulations were generated for each shift. Logistic regression and Spearman’s rank correlation coefficient (Rs) were used to measurepotential differences for the ranked dose parameters (3, 5, 10,&,70 Gy) andvolume parameters (1, 3, 5, 10,&,100 %) between patients with vs. without
late GI grade =/> 2.
Results: Late GI grade =/> 2 was observed in 24 (10%) patients. One single
dose level (40 Gy) was predicting late rectal toxicity with the static rectum andwith five of the shifts (0.1-0.4 and 0.6 cm) for all trials. With 1, 5 and 10 trials,
shifts of 0.8 cm significantly predicted this dose level as well. The predictive

M ONDAY, M AY 9, 2011
value (Rs) was typically lower for large shifts (Rs=0.072-0.094) than for small
shifts (Rs=0.088-0.099). When introducing motion, additional dose levels (15,50, 55 and 70 Gy) were found significantly associated with toxicity. For thevolume parameters, the 85 and 100% rectal volumes were significantly related to toxicity for both the static rectum and for the majority of the shifts. For
shifts of 0.2-0.4 cm, volume parameters between 40 and 60% also became
predictive for rectal toxicity.
Conclusions: We have shown that modelling rectal motion with normally distributed motion applied to the static rectum in the planning CT has potential
for prediction of rectal toxicity. Introducing the shifts lead to additional doseand volume parameters significantly related to toxicity as compared to thestatic rectum. In the further development of these investigations of translational shifts, also other motion patterns such as e.g. systematic shifts will be
included.
100 oral
USING LONGITUDINAL AND CIRCUMFERENTIAL PARAMETERSFROM ESOPHAGUS SURFACE DOSE DISTRIBUTIONS TO PREDICT ACUTE ESOPHAGITIS AFTER CONCURRENT CHEMO-IMRT
FOR LUNG CANCER
C. Chen1 , W. Heemsbergen1 , W. Uyterlinde2 , M. Heuvel van der2 , J. deBois1 , M. Rossi1 , J. J. Sonke1 , J. Belderbos1 , M. van Herk1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiotherapy, Amsterdam, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Thoracic Oncology, Amsterdam, Netherlands
Purpose: Acute esophagitis (AE) is a common side effect of high dose radiation with concurrent chemoradiotherapy in NSCLC patients. Currently, only
dosimetric constraints (e.g. V50, V35) derived from 3D conformal treatments
are applied in the clinic to limit and/or predict AE. There is however, a lack ofconsensus on the most predictive parameter. In a previous study on esophagus surface dose maps (ESDM), the local dose distribution was found to be
associated with AE, suggesting that a higher dose to a longer and/or wider
range of esophagus surface is associated with severe AE. Therefore, in thisstudy, we analyzed longitudinal and circumferential parameters, derived fromthe ESDM, and relate these to the incidence and severity of AE.
Materials: A group of 31 consecutive patients with AE Grade 0~3 (CTCv.3.0)
treated between 2008 and 2009 was selected for this study. Twenty Grade0~2 and 11 Grade 3 patients were categorized as non-toxic (NT) and toxic(T), respectively. All patients underwent daily concurrent chemoradiotherapy
using IMRT in 2.75Gy4 fractions. The esophagus cost function used for treatment planning was V35≤65%. For all patients an ESDM of the planned dose
was computed. Next, two sets of parameters were extracted: 1) the lengthof the esophagus that received more than DGy dose over more than X % of
its circumference on the axial slices and 2) the percentage of the circumference that received more than DGy dose over more than Lcm of its length.
Univariate binary logistic regression was applied to select the most predictive
parameter in either set.
Results: The lengths and circumferences in each set are highly correlated.
The best longitudinal parameter derived from the univariate regression was
the length of the esophagus that received more than 30Gy dose over morethan 70% of its circumference (p=0.056, OR=1.210). This parameter has amean of 10.0cm, with a range of 1.5 to 19.2cm. The best circumferential
parameter was the percentage of the circumference that received more than
65Gy dose over more than 3cm of its length (p=0.029, OR=17.023). Thisparameter has a mean of 58%, with a range of 0 to 100%. Both parameters
were superior to the dosimetric parameters V35 (p=0.085, OR=1.040) or V50(p=0.120, OR=1.035), which are often used in the clinic.

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101 oral
VALIDATION OF THE LQL MODEL FOR NTCP PREDICTION IN
LUNG CANCER PATIENTS TREATED WITH SBRT
A. Scheenstra1 , M. Rossi1 , J. S. A. Belderbos1 , E. Damen1 , M. van Herk1 ,J. J. Sonke1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiotherapy, Amsterdam, Netherlands
Purpose: The extreme high fraction size of stereotactic body radiotherapy(SBRT) as compared to conventionally fractionated radiation radiotherapy
casts doubt on the validity of the LQ model for SBRT. In vitro studies reporting a more linear relation between dose and cell kill at high doses led tothe introduction of the LQL model. In this study we compare the LQ-modeland LQL-model in-vivo by evaluating local lung perfusion reduction (LLPR)
measured with SPECT.
Materials: Forty-one lung cancer patients with peripheral tumors (< 5 cm)
treated with 3 fractions of 18 Gy were included in this study. Pre- and posttreatment (4 months) free breathing perfusion SPECT/CT scans with 99m Tc
were used to quantify the LLPR. The LLPR was related to the 3D dose
distribution by fitting a logistic 3-parameter NTCP model: LLPR = a / (1 +(D50/dose) k ) 2 . For this study, only well-perfused regions outside the PTV
were used. The 3D dose distribution was normalized to biologically equivalent fractions of 2 Gy according to the LQ model using α/β -ratios of 1 Gy, 2
Gy, 3 Gy, 4 Gy, 5 Gy, 7.5 Gy, 10 Gy, 20 Gy, 30 Gy and infinity. Dose normalization according to the LQL model was performed as proposed by Park et
al 1 : The dose was normalized for the same α/β -ratios as the LQ model andfor threshold doses (dt) between 0 and 18 Gy. The NTCP parameters were
optimized for each dose distribution returning the maximum log likelihood.
The best model, i.e. having a fit that results in the highest log likelihood, iscompared to the other models by the profile-likelihood.
Results: The optimal fit was with the LQL model with α/β =4 Gy, dt=12,
a=29.5, d50=40, and k=1.7. This was significantly different from the LQ model
fit with α/β =3 Gy and α/β =4 Gy, but not significantly different from LQL model
fits with α/β =4 Gy and dt=11 Gy and dt=15 Gy (Figure 1). Furthermore, most
LQL models with dt > 11 were not significantly different from the LQ model forthe same α/β -ratio.

Conclusions: This study indicates that the current LQ model with α/β =3 Gy
is suboptimal for SBRT. The preferred model is the LQL model with α/β =4 Gy
with dt between 11-16 Gy. These results support the reported linear relation
at high doses as reported in in vitro studies and endorse the LQL model. Thismodel should be confirmed on larger patient cohorts and for clinical toxicity
endpoints, such as the incidence of radiation pneumonitis. 1 Scheenstra etal. IJROBP 96(S1): 1017 (2010)2 Park et al. IJROBP 70(3): 847-52(2008)

Conclusions: This preliminary study shows that in NSCLC patients treatedwith concurrent chemoradiation, AE toxicity is associated with longitudinaland circumferential parameters describing the shape of the dose distribution on the esophagus. However, more data are required to compare theadditional predictive value of these parameters with conventional dosimetricparameters derived from DVHs.

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Physics Proffered Papers 2: Basic Dosimetry
102 oral
PERIPHERAL GAMMA DOSE AND THERMAL NEUTRON FLUENCIES EVALUATION IN DIFFERENT MATERIALS FOR IMRTF. Sansaloni1 , J. I. Lagares1 , J. Muñiz1 , M. R. Expósito2 , J. A. Terrón3 , L.
Núñez4 , R. Barquero5 , F. Sanchez-Doblado6
1
CIEMAT, Medical Applications Unit, Madrid, Spain
2
U NIVERSIDAD DE S EVILLA, Seville, Spain
3
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Sevilla, Spain
4
H OSPITAL U NIVERSITARIO P UERTA DE H IERRO, Majadahonda - Madrid,
Spain
5
H OSPITAL U NIVERSITARIO DE VALLADOLID, Valladolid, Spain
6
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Sevilla, Spain
Purpose: Gamma doses and thermal neutron fluencies are compared for
four different anthropomorphic NORMA phantoms [1] (polyethylene, polyethylene plus urea, nylon and a real tissue one made with bones and organs froma pork) in two radiotherapy treatments (head and abdomen) to evaluate thedifferences of each phantom with a real patient in order to measure gamma
and thermal neutron organ dose in real tissues.
Materials: The TLDs pair method consists in the combinations of two TLDs,
TLD-600 (LiF:Mg,Ti with 95.6% 6 Li and 4.4% 7 Li) and TLD-700 (LiF:Mg,Ti
with 0.01% 6 Li and 99.99% 7 Li). The different neutron cross section of 6 Li
and 7 Li allows separating gamma and thermal neutron contribution. The
TLD pairs were placed in various spots of NORMA phantoms. These are
distributed over the phantom in such a way that dose at different organ position could be expressed as a combination of dose at these points. The
four NORMA phantoms used are: an standard NORMA made of polyethylene, NORMA(Nu) that is build with polyethylene plus urea homogeneily distributed, NORMA(Ny) nylon made and NORMA(Eq) made with real tissue
from a pork. The NORMA phantoms received two radiotherapy treatment,
head and abdomen. The field size used was 10 x 10 cm2 at 8 angles equally
spaced and the number of monitor units (MU) in each incidence was 1125
(9000 MU in total). The treatments were delivered by means of a 15 MV
photon beam coming from a Siemens Primus Linac.
Results: Thermal neutron fluencies at different positions, for abdomen andhead treatments, are shown in table I. The thermal neutron fluencies werein agreement at most points, but some differences are found. In position
3, in head treatment, the thermals neutron fluence in NORMA(Eq) is much
lower than in the other NORMA phantoms. Another interesting point is thePelvis medium, in this region the neutron fluencies measured in NORMA(Eq)is larger than in the other phantoms. The gamma dose values ranging from 2
Sv near isocenter to 8 mSv at the most distant detector.

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104 oral

RE-ESTABLISHING THE PHOTON ABSORBED DOSE PRIMARYSTANDARD ON THE NPL CLINICAL LINAC
D. Shipley1 , J. Pearce1 , S. Duane1
1
N ATIONAL P HYSICAL L ABORATORY, Radiation Dosimetry, Teddington,
United Kingdom

SENSITIVITY OF THE CORRECTION FACTOR FOR USE IN
REFERENCE DOSIMETRY OF NONSTANDARD BEAMS TO DOSEHOMOGENEITY
E. Chung1 , E. Soisson2 , J. Seuntjens1

Purpose: The UK primary standard for absorbed dose in high-energy beams
is a graphite calorimeter. Secondary standard absorbed dose calibrations areconverted from graphite to water. In this work the primary standard was reestablished and the dose conversion was completed for MV photon beams
from the clinical linac at the National Physical Laboratory (NPL).
Materials: A set of type 2611 ionisation chambers were calibrated in agraphite phantom against the calorimeter in the 7 x-ray energies from the
NPL Elekta Synergy linac. This calibration was then converted to absorbed
dose to water. Secondary standard instruments were calibrated against thesereference chambers at either 5 or 7cm depth in water. Chamber calibrations
are normally given in terms of kQ, the ratio of the calibration factor in quality,
Q, to that in a reference quality, Q0 (60 Co at NPL) where the radiation quality
is defined in terms of tissue-phantom ratio (TPR20/10).Monte Carlo modelsof the linac source were developed for each energy using EGSnrc/BEAMnrc
to determine: corrections to account for the presence of gaps / non-graphite
materials in the calorimeter, water-to-graphite dose ratios in the phantoms,
and corrections to account for the different geometry of the calorimeter andgraphite phantom.For each energy, the source model was fine-tuned in a
30x30cm2 field by matching calculated and measured depth-dose and beamprofile data at different depths in water. The tuned model was validated bycomparing with measurements in a 10x10cm2 field at the reference depth.
Results: Calculated gap corrections were consistent with previous measurements made on the NPL research linac. Calculated water/graphite dose ratios varied from 1.081 for 4MV to 1.115 for 25MV x-rays and were consistent with previously calculated ratios for the research linac. The combined
standard uncertainty in the absorbed dose to water calibration of secondary
standard chambers is 0.7%.The quality dependent correction, kQ, for a type
2611 chamber is shown in Figure 1, together with a cubic fit to data previously
obtained on the NPL research linac.

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1

M C G ILL U NIVERSITY, Medical Physics Unit, Montreal, Canada
M C G ILL U NIVERSITY H EALTH C ENTER, Department of Medical Physics,
Montreal, Canada

2

Purpose: To investigate the sensitivity of the plan-class specific reference(pcsr) correction factor to dose homogeneity.
Materials: A cylindrical PMMA phantom filled with water was constructedat the center of which reference absorbed dose to water was measured. A
simple target volume was virtually constructed at the center of the cylindrical phantom and avoidance structures were contoured at various positions
around the target. Ten different TomoTherapy® -based IMRT fields were created with varying positioning of the avoidance structure and dose constraints.
Dose homogeneity was estimated for each IMRT field using three parameters
calculated from the treatment planning system: (i) modulation factor (MF) at
the whole target volume and (ii) a modified conformal index (COIN) and thehomogeneity index (HI) at the central region of the target volume, where aradiation detector or an ionization chamber was positioned. The relative dose
measurement for each IMRT field was carried out using a PTW micro liquid
ion chamber (microLion). Based on the new dosimetry formalism, a pcsr correction factor for each field was measured for two 0.6 cm3 Farmer-type chambers, Exradin A12 and NE2571, and a smaller (0.06 cm3 ) chamber, Exradin
A1SL. We analyzed the dependence of the measured pcsr correction factor
on the three dose homogeneity parameters.
Results: The uncertainty on the measured pcsr correction factor was in therange of 0.2-0.4 % and 0.2-0.7 % for the Farmer-type chambers and the
Exradin A1SL, respectively. For the two Farmer-type chambers, the correction factor of each IMRT field was the same within the measurement uncertainty. When the heterogeneity of the central target dose was less than 5 %along with values of MF and modified COIN lower than 2.0 and 0.025, respectively, the correction factor was not different from unity by more than 0.7% for the air-filled ionization chambers used in this work. For more heterogeneous dose deliveries, the correction factor differed from unity by up to 2
% for the Farmer-type chambers. For the Exradin A1SL, the correction factor
was closer to unity due to the reduced effect of dose gradients on the smallerchamber. However, for the smaller chamber, the correction factor was highlyvariable in different IMRT fields because of a more significant impact of positioning uncertainties on the response of this chamber.

Conclusions: We have shown that a pcsr correction factor can be specified as a function of dose homogeneity especially for Farmer-type chambers.
This work suggests the use of a parameter to quantify dose homogeneity inselecting a plan-class specific reference field for composite nonstandard field
dosimetry.

Conclusions: As it could be expected, the gamma doses rapidly decreased
with distance from isocenter. Regarding the neutron fluencies some differences have been found in head down region and in pelvis medium region.
Nevertheless, in the comparison with NORMA(Eq.), none of the NORMA
phantom studied is the most representative, except the NORMA(Ny), andthen the Norma phantom used in previous experiments (polyethylene) to evaluate neutron organ dose is a good approximation as a first step. The resultsfor NORMA (Ny) are always minor than the others phantoms probably due
it contains nitrogen. [1] Shez-Doblado, F, Domingo, C, G, F et al. On line
neutron dose evaluation in patients under radiotherapy. In:Dssel O, schlegelWC, editors. WC 2009, IFMBE Proccedings 25/I, Berlin: Springer. 2009;259261.[2] F. Vanhavere et al. Peripheral neutron and gamma doses in radiotherapy with an 18 MV linear accelerator. Radiat Prot Dosimetry. 2004;110(14):607-12

Figure 1: kQ as a function of TPR20/10.The combined standard uncertainty of kQ is estimated to be 0.56%, for both the original curve and the new
points, taking into account correlations in the component uncertainties in thisratio of calibration factors. kQ values for the new x-ray qualities are in good
agreement with the fit to existing qualities used on the research linac.
Conclusions: Absorbed dose to water has been determined in the MV
beams from the NPL clinical linac, via two routes traceable to the current primary standard. For now, 2611 ionisation chamber calibrations will continue tobe reported by normalising the existing kQ curve, however this will be reconsidered when the new NPL primary standard calorimeter is commissioned
and sufficient data from this new calorimeter is available.

105 oral
APPLICATION OF A NEW FORMALISM FOR REFERENCE DOSIMETRY IN TOMOTHERAPY FOR THREE CYLINDRICAL IONIZATIONCHAMBERS
F. Pupillo1 , M. Zeverino1 , G. Taccini1
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Medical Physics,
Genova, Italy
Purpose: Helical tomotherapy (HT) introduction in the clinical routine, andin general the introduction of IMRT techniques, which use small fields or extended fields composed of a multitude of smaller fields, has highlighted dosimetric errors whenever the reference dosimetry protocols (either IAEA TRS398 or AAPM TG-51) are applied. Reference conditions (rc) dictated by the
TRS-398 are expressed by the field size (10x10 cm2 ) and the source-detector
distance (100 cm) to the depth of measurement (10 cm). In the case of HT,
the SAD is fixed to 85 cm, while the field 10x5 cm2 results as the closest to
the reference standard. In addition, beam profiles produced by the machine
have a dose gradient in the radiation field due to the absence of flattening filter. Alfonso et al. have proposed a new formalism for the reference dosimetry,
introducing the kQmsr,Qfmsr,fref correction factor that rectifies the response ofionization chambers (ic) for differences between field size, shape, phantom
material and the beam quality in the case of a fref standard reference field
and in the case of machine-specific reference field fmsr.
Materials: This paper aims to apply this IAEA based formalism to the HT,S 40

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to 38% between Z+σ and Z-σ . (II) Clinical cases were analyzed by comparing PTV D90 for each quantity and similar results as in (I) were obtained. The
choice of scoring quantity has an important effect on dose volume histograms(Figure 1b).

featuring three different ics: Exradin A1SL, PTW 31014 PinPoint and PTW
31010 Semiflex. The first ic was chosen because it is considered as a HT
standard dosimeter, while the other two because they own the same cylindrical geometry with slightly different sensitive air volume than the former. A1SL
was used in pair with the electrometer TomoElectrometer, the other two withPTW UNIDOS E, which have been calibrated in absolute dose. The adopted
rc were: fmsr of 10x5 cm2 and 5x5 cm2 at 10 cm depth (SSD = 75 cm) and10 cm backscatter in a Virtual Water slabs phantom. The first step was toevaluate, in rc chosen, the correction factors to the reading of the ic due tothe beam quality and influence quantity. The same measurements were also
performed under the same HT-adopted rc on a linac Varian Clinac 2100C/D
to confirm the hypothesis of having carried out the measurements to the HTdose profile maximum. The factor kQmsr,Qfmsr,fref was obtained from a direct
calibration of the ic in the rc against a primary standard absorbed dose inwater calibrated or another dosimeter whose calibration is traceable to it: inthis case GafChromic EBT2 radiochromic films.
Results: We found an excellent agreement between correction factors kpol x
ks carried out from measurements performed on both HT and linac (p<0.01).
The determination of kQmsr,Qfmsr,fref is aligned to those found in literature,even though they were obtained choosing as independent an alanine dosimeter. Results for the correction factors are listed in Table 1.

Conclusions: Outstanding agreement is observed between measured andcalculated kQ factors. The level of agreement observed in this study indicates
that, for some chambers where only one chamber of each type is characterized, measured kQ factors are representative of the chamber type.
107 oralConclusions: Agreement of the correction factors between HT and linac confirms the validity of the measurements. The fmsr rc choice did not affect thedetermination of the correction factors. The kQmsr,Qfmsr,fref factors carriedout for the ics quantified the dosimetric error due to the beam variation and rc
difference.
106 oral
HOW ACCURATE ARE MONTE CARLO CALCULATED KQ FACTORSFOR EXTERNAL BEAM RADIOTHERAPY?
B. Muir1 , M. McEwen2 , D. Rogers1
1
C ARLETON U NIVERSITY, Physics Department, Ottawa, Canada
2
N ATIONAL R ESEARCH C OUNCIL OF C ANADA, Institute for National
Measurement Standards, Ottawa, Canada
Purpose: The journal Medical Physics recently published two papers thatreport kQ factors in photon beams for many different cylindrical ionizationchamber types. In one paper (McEwen, Med. Phys. 37 (2010) p. 21792193) measured kQ factors are provided for 27 types of ionization chamber.
In the other (Muir and Rogers, Med. Phys. 37 (2010) p. 5939-5950) Monte
Carlo calculated kQ factors are given for 32 ionization chamber types. This
work aims to synthesize these two data sets with the goals of i) confirming
the reliability of the results presented, ii) carrying out a detailed comparisonof measured and calculated factors, and iii) attempting to put an upper limiton the variation of W/e with beam energy.
Materials: As is the case for many primary laboratories, the NRC disseminates kQ factors via a set of reference ionization chambers. The accuracyof the measured kQ factors therefore ultimately rests on the calibration ofthese reference chambers (type NE2571) against the primary standard water calorimeter and this first step was reviewed in detail. Accuracy of Monte
Carlo calculated kQ factors is tested through comparison to kQ factors calculated with Monte Carlo simulations provided in other publications. The sleeveeffect (for non-waterproof chambers) is analyzed by comparing calculated kQ
factors for identical chambers with and without sleeves weighed against otherpublished results. Additionally, confidence in Monte Carlo calculated kQ factors is achieved through self-consistencies between kQ factors for various
graphite-walled Farmer-type chambers. The two data sets are compared interms of the percent difference between the experimental and Monte Carlocalculated results.
Results: The constancy of the NE2571 chambers at the sub-0.1 % level has
been confirmed by regular monitoring in a reference Co-60 field over a periodof more than fifteen years. Comparison of the measured NE2571 kQ factors
to other high quality experimental results (from a number of primary laboratories) shows agreement with the mean of all measurements within 0.2%.
Calculated kQ factors show excellent agreement with most other publishedMonte Carlo calculated kQ factors. Analysis of the sleeve effect shows expected results. Mean percent differences between experimental and Monte
Carlo calculated kQ factors are -0.08, -0.06 and -0.24 % for 6, 10 and 25
MV beam energies with standard deviation of the samples being 0.17, 0.33
and 0.31, respectively. The figure below shows the distribution of the percent
differences between the two data sets for all chambers investigated and thesubset that meet the specification of a reference-class instrument

SCINTILLATION DOSIMETRY IN EXTERNAL BEAM RADIATIONTHERAPY: REVIEW AND COMPARATIVE ANALYSIS OF THREE
APPROACHES
P. Z. Y. Liu1 2 , N. Suchowerska2 , P. Abolfathi2 , R. Wilkins3 , D. McKenzie1
1
U NIVERSITY OF S YDNEY, School of Physics, Sydney, Australia
2
S YDNEY C ANCER C ENTRE , R OYAL P RINCE A LFRED H OSPITAL, Camperdown, Sydney, Australia
3
B IOMECH, Sydney, Australia
Purpose: Scintillation dosimeters have many advantages over commerciallyavailable dosimeters including high spatial resolution and water equivalence.
However, in a megavoltage photon beam, a significant level of Cerenkov
background signal is generated in the optic fibre that conveys the signal to thereadout system. We compare three methods of accounting for this Cerenkov
background signal in a clinical setting.
Materials: Three commonly used methods to account for the Cerenkov background radiation in scintillation dosimetry include background fibre subtraction [Beddar 1992], spectral filtration [Fontbonne 2002] and air core dosimeter
design [Lambert 2008]. Prototypes using each of the three approaches wereconstructed and evaluated under clinical conditions in a 6 MV photon beam
(Varian). Each prototype was assessed for ease of use, reproducibility, stem
effect, field size dependence, accuracy of percentage depth dose and temporal resolution. In the background fibre method, the Cerenkov light signal in
the optic fibre is estimated from the light signal in a second adjacent fibre. In
the spectral filtration method, a mathematical procedure is used to calculate
the Cerenkov background from signals measured by a colour camera in two
different spectral regions. In the air core method, the optic fibre in the primarybeam is replaced by a silica tube silvered on its interior surfaces. Cerenkov
radiation is not generated in the air core.
Results: The background fibre method was found to be the least accurate
because the relative magnitude of Cerenkov light in the background and signal fibres were not identical. The spectral filtration method and the air core
method both accurately accounted for Cerenkov background radiation for allparameters tested. The former requires a complicated calibration procedure
and a long acquisition time while the latter attenuates the signal during propagation in the air core light guide. The uncertainties in the measured beam
output factor using the spectral filtration method and the air core method wasfound to be ±3% and ±1% respectively.

Conclusions: Both the spectral filtration method and the air core method
successfully operate in the presence of Cerenkov radiation. The choice between these two methods depends on clinical requirements. For example, thephysical flexibility of the polymer fibre used in the spectral filtration method ismore suitable for internal in-vivo dosimetry. However, dosimetry during highdose rate IMRT treatments can only be performed with the speed of the aircore method.Both the spectral filtration method and the air core method successfully operate in the presence of Cerenkov radiation. The choice between
these two methods depends on clinical requirements. For example, the physical flexibility of the polymer fibre used in the spectral filtration method is moresuitable for internal in-vivo dosimetry. However, dosimetry during high dose
rate IMRT treatments can only be performed with the speed of the air core
method.We thank National Health and Medical Research Council Australia
for funding.
108 oral
DOSE TO MEDIUM AND WATER IN LOW ENERGY BRACHYTHERAPY
G. Landry1 , J. P. Pignol2 , L. Beaulieu3 , F. Verhaegen1 , B. Reniers1
1

D EPARTMENT OF R ADIATION O NCOLOGY (MAASTRO), GROW, U NIVER -SITY H OSPITAL M AASTRICHT , Maastricht, Netherlands

2

O DETTE C ANCER C ENTRE , S UNNYBROOK H EALTH S CIENCES C ENTRE,
North York, Toronto, Canada
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Quebec, Canada

3

Purpose: The current brachytherapy dosimetry protocol, AAPM TG43, ignores the effects of heterogeneities and lack of backscatter. AAPM TG186
was mandated to investigate model based dose calculation algorithms (MBDCA) such as Monte Carlo (MC) simulations as an alternative to the TG43
approach. In TG43 radiation is transported away from sources in uniform water and the dose Dw,w is scored in that medium. MBDCA account for local
tissue density ρ and composition Z and inherently calculate Dm,m, i.e. radiation transported in the local medium and dose scored in that medium. It isthought that some cells’ radiation response is better correlated to Dw,m, i.e.
radiation transported in the local medium but dose scored in a small water
volume. In low energy brachytherapy using 125 I, 103 Pd or electronic sources
the photoelectric effect is expected to cause large Z-induced differences between Dm,m and Dw,m which vary with tissue type. The goal of this study
was to quantify these differences for a series of human tissues for single point
sources and clinical implants, regardless of which quantity is better suited for
dose reporting.
Materials: The GEANT4 MC code was used to perform Dm,m and Dw,mcalculations for (I) spherical geometries with point sources emitting real spectra and (II) clinical seed implants with real source models (125 I prostate, 103 Pd
breast, 4 patients each). 19 tissue compositions were studied to assess themagnitude of Dw,m/Dm,m and its dependence on Z as well as on its uncertainty; for a given tissue type such as breast, the mean Z was studied as wellas Z±σ .
Results: (I) We found differences between Dm,m and Dw,m to be significant(>5%) for all tissues involved in brachytherapy, with differences of up to 70%
for adipose tissue and 8% for prostate tissue. It was found that Dw,m/Dm,mis fairly constant with distance from the source and does not vary significantly between sources (Figure 1a, breast as example), simplifying conversions from one quantity to the other. Furthermore Dw,m/Dm,m varied by up

Conclusions: In going away from TG43 and Dw,w the choice of scoring
Dm,m or Dw,m is crucial given the large differences between the two quantities. Guidelines are necessary to avoid reporting of different quantities indifferent centres. Should conversion from one to the other be necessary, ourwork shows that a single source dependent factor is accurate enough.

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110 oral

RTT Proffered Papers 1: Professional Development and Risk Management
109 oral
FIRST RESULTS OF A WORLDWIDE SURVEY ON RESPONSIBILITIES AND RESOURCES IN MODERN RADIATION THERAPY.
R. de Jong1 , J. Nijkamp1 , C. Rasch1
1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

Purpose: IMRT and IGRT are increasingly being implemented in radiation
therapy departments. While most literature focuses on the technical aspectsof the development and implementation of these modern techniques, little is
known about the practical implementation. Many steps in the chain of radiation therapy can be distinguished and different disciplines are involved inthese steps. The aim of this study was to assess the available human resources and responsibilities per discipline with respect to the use of IMRTand IGRT in different departments worldwide.
Materials: We sent out a questionnaire by e-mail to everyone who participated in the ESTRO course "IGRT in clinical practice" between 2006 and2009. The questionnaire addressed questions on department size, availability of human and hardware resources and on the responsibilities of different
disciplines in pre-defined steps of IMRT and IGRT.Disciplines evaluated were
physician, physicist and RTT. The chain of radiation therapy was divided in
6 steps: indication of treatment, pre-treatment imaging (CT/simulation), delineation of organs at risk and target volumes, treatment planning, treatment
delivery, and IGRT (acquisition, registration, evaluation).
Results: Of 480 sent questionnaires, 49 responses were received from 40
different hospitals originating from 19 countries (15 Europe, 1 Canada, 1 Australia, 1 China, 1 South-Africa). The total amount of human resources is 11.1
per linac, ranging from 6.0 to 18.6 (Table 1): it is clear that large differences
between departments exist. There were, however, no clear correlations between number of linacs and any of the other resource parameters.With respect to the responsibilities for the different steps in radiation therapy large
consensus was found for: indication of treatment, pre-treatment imaging, delineation of target volumes, treatment delivery, and IGRT acquisition and registration. For delineation of OAR, treatment planning and IGRT evaluation,
however, large differences existed (Table 1).

A UK APPROACH TO PATIENT SAFETY IN RADIOTHERAPY: HPA
INITIATIVES
U. O’Doherty1 , K. Baldwin1
1
H EALTH P ROTECTION AGENCY, Medical Exposure Department, Chilton,
Didcot, Oxfordshire, United Kingdom

Purpose: With a focus on patient safety the Health Protection Agency (HPA)
provides a dedicated resource to support the radiotherapy community. The
HPA is an independent organisation whose role is to provide an integrated
approach to protecting UK public health. Part of its remit includes the provision of independent advice on radiological practice and radiation safety. The
organisation provides an impartial resource equipped with the knowledge andskills to work in partnership with health care professionals within the clinicalsetting. This paper discusses three distinct, but linked elements of this initiative intended to support effective and safe radiotherapy throughout the UK:1.
national collection and analysis of radiotherapy incidents and near misseswith promulgation of learning across the community2. programme of clinicalsite visits to departments 3. work of the HPA Patient Safety in Radiotherapy
Steering Group (PSRT)
Materials: 1. In the UK, the National Patient Safety Agency (NPSA) has
an established system of voluntary reporting of incidents and near misses,
including those in radiotherapy, called the National Reporting and Learning
Service (NRLS). The HPA has a data sharing agreement with the NPSA toprovide the expertise to undertake the analysis of data collected on radiation incidents on a regular basis. The classification and coding system form
’Towards Safer Radiotherapy’ is employed for the purposes of this analysis.
Reports are routinely published on the HPA website, thus enabling the national sharing of any lessons learnt from incidents and near misses.2. A programme of site visits has been undertaken to provide independent support
to clinical radiotherapy departments. Examples of safe practice are shared
between departments and centres are supported in improving patient safety
and process efficiency in radiotherapy, within the context of legislation. This
work draws on knowledge of data provided by a national collection and analysis of radiotherapy incidents, whether near misses or reportable events, thus
promulgating this experience across the community. 3. The primary objectiveof the HPA PSRT steering group is to improve patient safety in radiotherapy
in the UK by building on the recommendations of ’Towards Safer Radiotherapy’ supporting their implementation and taking them forward. This group is
currently working to identify the underlying causes of radiotherapy errors andthe methods of detection of errors.
Results: 1. Up-to-date analysis of over 2,500 radiotherapy incidents andnear misses will be presented. The vast majority of these events have not
had clinically significant outcomes.2. Common recommendations and examples of safe practice will be shared from over 30 HPA clinical sites visits. 3.
An update on the key workstreams of the HPA PSRT steering Group will be
described.
Conclusions: The HPA continue to work in partnership with the UK community supporting and implementing initiatives to forward patient safety inradiotherapy.
111 oral
PATIENT EDUCATION IN 3D - ”THIS IS HOW RADIATION THERAPYIS DONE”
A. Boejen1 , L. Bloch-Larsen1 , R. L. Poulsen1 , K. Seiersen2
1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark

Conclusions: We found that large variation exists between departments inthe amount of human resources per linac and their distribution in different
disciplines. In particular, responsibilities for treatment planning and IGRT
evaluation differed. Our next step is to investigate the causes of the differences in available resources and responsibilities between departments, andtheir subsequent effect on quality and cost effectiveness.

Purpose: Department of Oncology established in March 2007 a Learning
Centre for Radiotherapy. A part of the centre is a virtual Environment forRadiotherapy Training (VERT). This provides a life size virtual radiotherapy
treatment room with all its equipment and a patient on the treatment couch.
VERT aims to provide the trainee with simulation and visualization of the fullfunctionality of the treatment equipment.To test if VERT is a suitable facility foreducation of patients and their relatives, too, a pilot project was establishedin the autumn 2010.
Materials: Four ’Open House’ events of 90 minutes were organized. Patientsand relatives could arrive without prior registration. The aim was to provide
a radiation physical and technical explanation of effect, planning and delivery of radiotherapy at layman’s level. The presentations alternated between
PowerPoint and demonstrations of VERT. The participants were invited to ask
questions along the way. The contents were demonstration of the accelerator;
isocentre’s significant for dose planning and treatment execution, examplesof technical details with risk for breakdown and waiting time for patients; treatment preparation with fixation, presentation of three selected treatment plans
in 3D, contouring of tumor and organs at risk, field entrances, dose distribution, the importance of positioning and examples of IMRT and rotation IMRT,QA ex IGRT with match of CBCT.
Results: 13 patients and 12 relatives participated in the education. The questions were answered by use of Turning Point.Before the education 48% of

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participants rated their level of knowledge about RT to be medium and 38%
to be small. 52% of participants had received their primary knowledge about
RT from staff in radiotherapy, 24% from family and friends, while 19% haveobtained it from a mailed DVD. 62% felt confident, 24% are a little nervous
and 14% mean nervous at the thought of RT. After the education 25% of participants rated they were less nervous. 88% had understood the importanceof proper positioning at a high level. 71% believed greatly to understand how
RT is going on. 92% of participants believed that teaching had been greatly
relevant, and time allocation of 90 minutes was appropriate. 70% wish to see
a general treatment plan corresponding to their treatment plan, while 83%
would like to see their own treatment plan in 3D. "It would have been great
to know that before. When I’m lying in the mask and can’t see anything, it’s
nice to know what’s going on around me" was one of the comments from theparticipants.
Conclusions: Patients and relatives were very satisfied. The responses indicate that teaching had been highly relevant, the patients were less anxious
and their knowledge level had increased. Their recommendations were that
we must proceed with the offer. The duration of 90 minutes is appropriate.
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SEVEN YEAR REVIEW OF A RADIOTHERAPY INCIDENT REPORTING AND LEARNING SYSTEM
D. Routsis1 , M. Williams1
1
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Radiotherapy Department, Cambridge, United Kingdom
Purpose: Safety in radiotherapy is of paramount importance. Nationalguidelines1 recommend the use of service monitoring, recording episodes
where errors could have or did occur. By assessing the frequency of reported
incidents and near misses and identifying the service area in which they occur, process deficiencies can be identified and hopefully resolved. A monitoring system has been in place in Addenbrooke’s Radiotherapy Centre for 7
years. One of the most common errors in radiotherapy has been highlighted2
as mistakes in applying planned positional movements of the radiation fieldfrom the external reference marks on patients. This review aimed to assess
the affect of local process changes on incidents in radiotherapy, specificallythose attributable to incorrect moves from reference marks.
Materials: The incident logging database was interrogated to quantify thereported episodes of errors in ’Movement from Reference Marks’. Errors wereclassified according to national guidelines1 , reflecting the magnitude of theclinical implication on the patient. Analysis was carried out to identify the partsof the radiotherapy pathway where the errors were most frequently occurring.
The errors were compared against the timeline of service improvements.
Results: Between 2004 and November 2010, 718 episodes were reportedout of 28447 treatment courses. 81 (10% of all episodes) were due to incorrect movements from reference marks, 0.3% of all courses. 53 (6.8%)of these were classified as incidents (any radiation given to incorrect target)and 28 (3.2%) were classified as near misses (incorrect moves detected earlier in pathway). Most common causes within this category were applying
moves in wrong direction (37%) or omitting to apply moves (33%). Incidenceof movement errors was highest in 2006; there has been a threefold decrease
to 2010 (see figure 1). From 2006, improved checking processes had been
established.Between 2004 and November 2010, 718 episodes were reportedout of 28447 treatment courses. 81 (10% of all episodes) were due to incorrect movements from reference marks, 0.3% of all courses. 53 (6.8%) of
these were classified as incidents (any radiation given to incorrect target) and28 (3.2%) were classified as near misses (incorrect moves detected earlier
in pathway). Most common causes within this category were applying moves
in wrong directions (37%) or omitting to apply moves (33%). Incidence of
movement errors was highest in 2006; there has been a threefold decrease
to 2010 (see figure 1). From 2006, improved checking processes had been
established.
Conclusions: Errors due to moves from references occurred in 0.6% ofcourses in 2006 but have decreased to 0.2% in 2010. Double checking systems established throughout the radiotherapy pathway have proven effectiveat detecting errors earlier in the treatment pathway; more near misses arebeing reported than radiation incidents. Where errors have made it throughthe pathway to actual treatment delivery, the magnitude of the clinical implication on the patient has reduced as these are detected by the increased useof portal imaging. Improvements are needed in applying moves in the correct
direction and in reducing incidences of omissions. By using radiotherapy incident reporting systems, those practices that have been effective in improving
patient safety and those areas where improvements need to be made havebeen identified.

References1. The Royal College of Radiologists, Society and College of Radiographers, Institute of Physics and Engineering in Medicine, National Patient Safety Agency, British Institute of Radiology. Towards Safer Radiotherapy. London: The Royal College of Radiologists; 2008.2. Health Protection
Agency. Radiotherapy Newsletter of the HPA: Safer Radiotherapy. Issue 1
ed; 2010.
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HOW MUCH EXPERIENCE IS ENOUGH? A COMPARATIVE ANALYSIS OF IMRT PLANS
V. Batumalai1 , M. Jameson12 , S. Blakeney1 , I. Franji1 , K. Andrew1 , C.
Nguyen1 , A. Wallis1 , D. Forstner1 , P. Vial13 , L. Holloway123
1
C ANCER T HERAPY C ENTRE , L IVERPOOL H OSPITAL, Radiation Oncology,
NSW, Australia
2
C ENTRE FOR M EDICAL R ADIATION P HYSICS , U NIVERSITY OF W OLLON GONG , Medical Physics, Wollongong, Australia
3
I NSTITUTE OF M EDICAL P HYSICS , S CHOOL OF M EDICAL P HYSICS ,U NIVERSITY OF S YDNEY, Medical Physics, NSW, Australia
Purpose: Intensity Modulated Radiation Therapy (IMRT) is becoming thestandard of care for many patients in radiation oncology. Treatment planningfor IMRT is a complex process that requires additional training and expertise. In order to implement IMRT in a manner appropriate for a department’s
resources it would be helpful to know: how much treatment planning experience is enough? The aim of this study was to compare and analyse IMRT
plans generated by radiation therapy technologists (RTT) with varying levelsof IMRT planning experience.
Materials: A patient treated with IMRT for a stage IVB malignant lesion of theleft tonsil was retrospectively selected. The patient’s pre-existing planningtarget volumes (PTV) and all organs at risk were provided with the computed
tomography (CT) dataset. Four RTTs with varying levels of IMRT planning
experience were selected. The level of experience was defined by the number of clinical IMRT plans completed each by RTT A, B, C and D; 17,16,8
and 7 plans respectively. All RTTs generated an IMRT plan according to
the prescription, objectives and constraints as outlined in the department’s
IMRT protocol and without any additional assistance. Visual plan analysis
was carried out by an experienced head and neck radiation oncologist. Dosevolume histograms (DVH) were calculated for each plan to assess against
the supplied planning criteria. Radiobiological assessment was performed by
calculating an equivalent uniform dose (EUD) based figure-of-merit (fEUD) to
quantify the overall plan quality. A greater fEUD value indicates a superior
plan. Treatment delivery efficiency was determined by comparing the numberof beams and segments, and total monitor units (MU).
Results: Plan A and C met the prescription criteria for PTV70 and PTV54,
and plan B and D had minor variations. All four plans satisfied the constraints/objectives for brainstem, spinal cord, mandible and oral cavity. Noneof the plans were able to fulfil the objectives for the right parotid and glottic
larynx but were still considered to be clinically acceptable, due to the close
proximity of the PTV to these structures. The resulting fEUD score shows thatthe quality of the plans is comparable to each other. However, the number ofsegments and MUs varied for each plan. Although plan D scored the highest
fEUD, it also produced the highest number of beams, segments and MUs,
which may not be necessary as demonstrated by the other plans.

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this essential workforce demographic. Only with a satisfied and committed
radiographer workforce will the profession meet the seemingly conflicting objectives of increased workload targets, improving efficiency, effectiveness andpatient centred care. This work identifies a number of relatively simple yet
effects measures that may improve job satisfaction and facilitate personal
and professional development and potentially increase organisational performance and the quality of care to the patient.

Conclusions: Although the plans were not able to fulfil the planning criteria
strictly, all the plans were considered to be clinically acceptable. This planningstudy demonstrated that even with different levels of planning experience it
may be possible for RTTs to produce treatment plans with comparable results
provided adequate training is provided and the planning goals are clearly
defined. However, treatment delivery efficiency should also be consideredwhen planning.
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INVESTIGATING THE FACTORS THAT INFLUENCE JOB SATISFACTION AT THE START OF A THERAPY RADIOGRAPHERS CAREER
D. Hutton1 , A. Eddy2
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Bebington, Merseyside, United
Kingdom
2
S HEFFIELD H ALLAM U NIVERSITY, Sheffield, United Kingdom
Purpose: Retaining and developing an adequately qualified and committed
workforce is a prerequisite to a well-functioning organisation. Staff shortages in radiotherapy has been a historic problem with the greatest retention
challenge that of junior professionals. Recruitment and retention of radiography staff in the NHS is an important yet largely neglected research domain. The importance of successful recruitment and retention strategies will
increase significantly with more challenging workload targets associated witheffectively utilising new technology and the increase in cancer incidence.This
Works seeks to:- Obtain a detailed understanding of the current professional
experiences of Therapy Radiographers from graduation to their first senior /supervisor position. Identify how and why certain factors influence perceptions of job satisfaction. Support the development of future strategies thatcan be employed to increase the level of job satisfaction for this group ofpractitioners. Inform a phase II study comprising a national questionnaire.
Materials: A qualitative study was undertaken employing a case study approach to explore the professional experience of therapy radiographers in two
departments. The sample consists of two large centres in the North of England. The selection of the centres has been based on a number of pragmatic
reasons. One of these centres has identified retention as an issue though a
National Radiotherapy forum, and the other volunteered for the study. Bothcentres have a large number of eligible participants. The four focus groups
comprised 34 participants in total. The age range of the participants was 22-42 years old, with years qualified ranging from <1 to 19 years. The four focus
groups were recorded and then transcribed per Verbatim. Thematic analysis
was employed to identify emergent categories and themes. These categories
informed the development of a thematic framework, facilitating comparison
between and within cases.
Results: Job satisfaction is multifaceted and is dependant on the individual,
context of work and the environment. The participants identified diverse but
interlinking facets that influence satisfaction in their role. Key themes include;
support through transition, professional development, control and autonomy
and the nature of the work performed.
Conclusions: Enhanced insight into the professional experience of therapy
radiographers is valuable to inform retention and development strategies of

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Award lecture

SymposiumAward Lectures

Are there (re)new indications for brachytherapy

116 speaker

119 speaker

ESTRO - 30 YEARS IN 30 MINUTES
J. Overgaard1

BRACHYTHERAPY OF THE LIVER
G. Gademann1 , J. Ricke2
1
OTTO - VON -G UERICKE -U NIVERSITÄT, Department of Radiotherapy,
Magdeburg, Germany
2
OTTO - VON -G UERICKE -U NIVERSITÄT, Department of Radiology andNuclear Medicine, Magdeburg, Germany

115 oral

1
A ARHUS U NIVERSITY H OSPITAL, Department of Experimental ClinicalOncology, Aarhus C, Denmark

NATIONAL INCIDENT REPORTING AND LEARNING SYSTEM
S. Levernes1 2
1
N ORWEGIAN R ADIATION P ROTECTION AUTHORITY (NRPA), Quality
Assurance, Osteras, Norway
2
DNR - N ORWEGIAN R ADIUM H OSPITAL, Medical Physics, Oslo, Norway

The lecture will be a trip down memory lane exploring the history, achievements and visions of ESTRO during 30 years.

Purpose: According to national regulations in Norway all radiotherapy departments shall have an incident reporting system. To help the departments
fulfil this requirement the radiotherapy quality assurance group (KVIST) at
NRPA established a working group with participants from all radiotherapy departments. This group came up with a proposal for a national system thathave been used in all radiotherapy departments since 2003.
Materials: The system is aiming at a very low reporting threshold to be alearning system catching problems before serious incidents happen. If serious incidents happen they will of course be reported further to the hospitalquality system. The incident system is non-anonymous to be able to retrieve
more information if necessary, but effort is put on the aspect that the systemshall be non-blaming, but rewarding reporting. The classification has ten different areas: 1) type of incident 2) no of patients involved3) primary cause ofincident 4) contributing causes5) seriousness for patient(s) 6) potential seriousness7) place of origin 8) proposed actions 9) patient/physician informed10) reported to hospital A common coding system is used for each of theseareas.
Results: The main part of the system is the local system in each department
with quality groups, reporting forms and common classification and coding. A
database solution for the local registration is also developed, but several hospitals have later on implemented the classification and coding system into thehospital quality system. Immediate actions have to be taken at the place theincident was detected, and the initial incident message is generated there.
The local quality groups are responsible for follow-up of the incidents, collecting all necessary information; eventually propose actions to avoid similar incidents, present results for administrative leaders and clinical personnel, andfor classification and coding in the database. On the national level the KVISTgroup annually is collecting statistics from the local systems into a national
database. Anonymized summaries of serious incidents are also reported together with the statistics, and collocated into an internal report. This reportand incident statistics are presented by the KVIST group for representatives
from all ten radiotherapy centres on annual meetings; and experiences, proposals and adjustments are discussed. So far (2003-2009) 5129 incidents
are reported into the national system. Detailed statistics will be presented at
the meeting.
Conclusions: Experience shows: - system facilitates awareness of incidents,
low threshold for reporting, learning without blaming- has provided significant
knowledge locally and nationally using common classification and coding- an
independent national body with competence in radiotherapy - in close cooperation with local quality groups at all radiotherapy centres - is necessary for
coordination, development, and for inspiration locally

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DOSIMETRIC COMPARISON OF LIVER TUMOUR RADIOTHERAPYIN ALL RESPIRATORY PHASES AND IN ONE PHASE USING 4DCT
D. Gabrys1 , R. Kulik2 , K. Trela1 , K. Slosarek2
1

M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTE
G LIWICE B RANCH, Department of Radiotherapy, Gliwice,
Poland2
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , Department of Radiotherapy Planning,Gliwice, Poland
OF O NCOLOGY,

Purpose: Liver tumours exhibit significant intrafractional motions due to respiration therefore 4DCT as well as gated radiotherapy are introduced into
treatment. We could delineate target volume on all respiratory phases andradiation is delivered during free breathing cycle. However the 4DCT technique synchronizes image acquisition with respiratory phase what allows us
to delineate our target on the basis of one respiratory phase and deliver gatedtreatment choosing specific phase for irradiation. Up to now littlie is know
about comparison of both techniques in terms of target and normal tissue
dose distribution.
Materials: In the present paper we analyzed data of 20 patients treated forliver metastases, irradiated to the total dose 36 Gy in 3 fractions. We chose
only tumours, which were clearly separated from the liver tissue. We used
4DCT to characterize tumor motion and create treatment volumes. For all patients we delineated two GTV, one based on all 10 respiratory phases (GTV4D) and based on one phase (GTV GAT). To create PTV’s we added thesame 0,5 mm to GTVs. Two treatment plans were performed (4D and GAT)and dose volume distributions were analyzed in respect to target and normal
tissue. Various tumour motions was included, motion along the superiorinferior direction was greatest mean 1,5 cm (range 1-3), to the side mean motion
was 0.9 cm (0.6-1.3). GTVs volumes were larger in 4D than in GAT, mean
14.9 vs 27.6 cm3, also PTV 37 vs 61 were larger.
Results: We achieved similar dose distribution in PTV4D mean 36.7Gy SD± 0.2 and minimum 34.9 Gy ± 0.3 for 4D plan, and PTVGAT for GAT plan
mean 36.7 Gy SD ± 0.3 and minimum 34.9 Gy ± 0.3, but when we look at thedose distribution in PTV4D in the GAT plan, we found decrease in minimum
dose to 12.3 Gy (2.2-24.3), and mean 33.9 Gy ± 2.3, what could be explain
by differences in target volumes related to tumour movement. Radiotherapy
delivered using GAT gave lower liver doses than using 4D with reduction ofmean volume receiving 5 Gy by 9.3% SD ± 4.7, V10 Gy 6.7 % SD ± 4.2,
V20 Gy 4.8% SD ± 2.7 and reduction of mean kidney volume receiving 5 Gy
by 12% SD ± 10, V10 Gy 7% SD ± 9, V20 Gy 2.8% SD ± 5.6. Moreover
doses to the other normal tissues were also lower. We also found correlation between GTV volume reduction with GAT, GTV motion and doses to thenormal tissues.
Conclusions: Gated radiotherapy allow us to decrease GTV and PTV volumes in comparison to volumes delineated on all respiratory phases. Decreased target volumes are responsible for improvement in dose distribution
in normal tissue especially in the liver and kidney.

Purpose/Objective: Liver metastases mostly of colorectal cancer as well as
the hepatocellular carcinoma show an increasing number and gain more andmore clinical relevance.
Surgical resection and the different ablation techniques demonstrate that allkind of local cytoreduction can result in a delay of systemic chemotherapy
and also an increasing survival time. However, they have anatomical andsize limitations.
We want to present results of an interdisciplinary approach to treat malignant
lesions by CT- or MR-guided brachytherapy. The interventions are performed
jointly by an interventional radiologist as well as a radiotherapist, using interstitial highs dose rate brachytherapy.
Material and Method: The technique of CT-guided brachytherapy in the radiological department is the following: a number of catheders (1 to 7, mean
4 depending on the geometry and size of the target volume) are placed in
the tumor using image guidance with fluoroscopy CT or MRI. After puncture of the tumor in the appropriate patient position using a 18-gauge needle, angiography sheats of 6F in diameter are inserted over a stiff angiography guidewire. Finally, 16 gauche brachytherapy catheters are placed in the
sheath and fixed.Finally, a 3D CT or MR data set is acquired for treatment
planning purposes.
The patient is transported to the brachytherapy room in the department ofradiotherapy in supine or prone position. The CT or MRI images are transfered by network to the planning program (Oncentra). The target volume andOARs and the catheders are defined and an optimal dose distribution using
automatic and manual tools is calculated. Treatment time is limited to appr.
one hour.
The prescribed tumor surrounding dose for metastases of colorectal cancer
is at least 20 Gy, for the hepatocellular carcinoma 15 Gy. No dose restrictions
inside the CTV apply. The limitation to the normal tissue is defined, i.e. forthe liver less than 5 Gy to at least 30 % of the volume.
Mean patient number per week is ten, with a maximum number per day of 5.
So far, more than 6000 patients have been treated since the introduction of
the method in 2004.
Results: Local control of liver metastases after interstitial brachytherapy isstrongly dose dependent. Depending on the histopathology as well as thesize of liver malignancies, local tumor control after 12 months usually is higher
than 90%. HCC lesions as well as metastastic breast cancer need much
lower doses than colorectal cancer. Technically, neither a size limit nor restrictions towards tumor location apply, i.e. in the liver hilum or liver dome.
Prospective randomized or songle arm data is available primarily for colorectal cancer as well as HCC. In both tumor entities, a significant prognostic
benefit of the brachytherapy approach has been proven recently. Complcations are uncommon and usually occur in patients with liver cirrhosis. In thesepatients, symptomatic bleeding or abscess formation may occur in up to 3%
of interventions.
Conclusion: Brachytherapy is safe and has proven prognostic benefit in colorectal liver metastases as well as HCC patients.
120 oral
WHAT REMAIN THE BEST INDICATIONS FOR BRACHYTHERAPY IN
HEAD AND NECK CANCERS?
G. Kovács1 , J. E. Meyer2
1
U NIVERSITY OF L UEBECK, Interdisciplinary Brachytherapy unit, Luebeck,Germany2
U NIVERSITY OF L UEBECK, Head and Neck Surgery, Luebeck, Germany
Purpose: Classic indication for head and neck brachytherapy were the curative and solely interstitial/mould therapy of primary T1-T2 nodal negative cancers as well, rarely, salvage treatments of small recurrent tumors in previously
irradiated areas. Due to the developments in surgery (use of lasers, improved
reconstruction techniques) as well radioprotection issues this entities are
cured nowadays primarily by surgery. In the past years, improved brachytherapy technology (introduction of remote controlled stepping sources) and theuse of advanced software solutions in treatment planning as well incorporation of modern imaging methodology (MRI, PET) offer a great potential ofusing brachytherapy as an effective dose escalation method with less normal
tissue radiation compared to any external beam radiation technique. Furthermore, interdisciplinary cooperation with surgical specialities (head and necksurgery, neurosurgery, dento-maxillo-facial surgery, ophthalmology) lead tosuccessful use of intra-/perioperative brachytherapy for clearance/dose esca-

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lation of surgical margins. This can lead due to lower level of external beam
radiation and/or less aggressive surgery to organ and function preservation.
Materials: Some groups published clinical data showing comparable or better tumor controle with improvements in functional results and in patient quality of life by using interstitial brachytherapy boost compared to different kindof modern external beam radiation techniques (+/- chemotherapy) in baseof tongue/oropharynx cancer as well nasopharyngeal tumors.Others reachedremarkable function (visual acuity) preservation in advanced paranasal/nasal
cavity cancers by using a multidisciplinary aproach combining externalbeam radiochemotherapy, interstitial brachytherapy and function preservative
surgery, however, prospective clinical studies on this field needs to be performed.The use of brachytherapy for salvage in presiously irradiated regionsof the head and neck in combination with ablative and advanced reconstructive surgery has a great potential in a strongly selected patient cohort.
Results:
Conclusions: It is in the responsibility of the brachytherapy community to use
this potential and drive multicentric and prospective comparative studies to beable defining and presenting the important role of modern brachytherapy inthe treatment of head and neck malignancies.
121 speaker
MRI GUIDED ROBOTICS IN BRACHYTHERAPY
M. Moerland1 , M. van den Bosch1 , F. Sollén2 , M. van Vulpen1 , J. Lagendijk1
1
U.M.C. U TRECHT, Department of Radiotherapy, Utrecht, Netherlands
2
N UCLETRON BV, Veenendaal, Netherlands
In the diagnostic and treatment procedures such as biopsies and brachytherapy for prostate cancer, magnetic resonance imaging (MRI) offers superior
soft tissue contrast and consequently improved detection of tumour lesions
and organs at risk. Therefore, MR-compatible robotic systems allowing real
on-line MRI-guided needle placement would be extremely valuable with theseprocedures. A number of MR-compatible devices, ranging from a simple
manipulator to a fully automated system, have been developed or are under development to biopsy suspicious cancer areas or to treat cancer areas,e.g. in prostate or breast.Technical difficulties, such as the restriction of using
solely non-ferromagnetic materials, the limited space within the MR bore, theneedle-induced prostate deformation, the needle-induced susceptibility imaging artefacts and the RF heating of the needles and catheters, make robotic
MRI guidance a hard task. Furthermore, the robotic device generally needs tobe coupled to an MR compatible machine for real MRI-guided treatment, e.g.
an MR compatible HDR brachytherapy afterloader.In this presentation we describe the status of different devices and their applications with focus on our
University Medical Center Utrecht (UMCU) robot dedicated to MRI-guided interventions in prostate cancer patients (see figure) and the first steps in thedevelopment of an MR compatible brachytherapy afterloader to be used in
combination with an MR scanner in a shielded treatment room.

M ONDAY, M AY 9, 2011

M ONDAY, M AY 9, 2011
124 speaker

Risks to normal tissue from current and emerging
radiotherapy modalities: the results and recommendations of the ALLEGRO Project
122 speaker
THE ALLEGRO PROJECT: AN OVERVIEW
A. Ottolenghi1 , K. R. Trott2 , V. Smyth1
1
2

U NIVERSITA DEGLI S TUDI DI PAVIA, Pavia, Italy
S T. B ARTHOLOMEW ’ S M EDICAL C OLLEGE, London, United Kingdom

The ALLEGRO Project has the full title "Early and late health risks to normal/healthy tissues from the use of existing and emerging techniques for radiation therapy". It was funded by Euratom for 2 years 2010-11 to define thecurrent state of the art of understanding and assessment of normal tissuerisks from radiation therapy, in order to be able to provide advice on clinicaltreatment choices and also set the direction for future research efforts.The
project investigations were divided into:
1. measurement and modelling of radiation doses outside the treatment
volume from photon, proton, and carbon ion beams;
2. review and development of current best practice in normal tissue complication probability (NTCP) modelling in head and neck, lung, andprostate cancer;
3. review and test of current research capability on the risks of second
cancer following radiotherapy.
As well as results from the individual investigations, a series of report documents have been produced that summarise the experience gained during
the project and providing recommendations for clinical practice in both current and emerging therapy modalities in order to minimise normal tissue risk
without compromising treatment efficacy, and also to indicate valuable areas
for further research. The research leading to these results has received funding from the European Atomic Energy Community’s Seventh Framework Programme (FP7/2007-2011) under grant agreement n◦ 231965 ("ALLEGRO"
project).
123 speaker
DOSIMETRY FOR NORMAL TISSUE RISK ASSESSMENT: MEASUREMENT AND CALCULATION OF THE DOSES RECEIVED BYNORMAL TISSUES FROM RADIATION THERAPY FROM CURRENTAND EMERGING MODALITIES
M. Durante1 , L. Sihver2 , E. Aird3 , B. A. Jereczek-Fossa4 ,F. Van den Heuvel5
1
G ESELLSCHAFT FÜR S CHWERIONENFORSCHUNG, Darmstadt, Germany
2
C HALMERS U NIVERSITY OF T ECHNOLOGY, Göteborg, Sweden
3
M OUNT V ERNON H OSPITAL, Northwood Middlesex, United Kingdom
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Milan, Italy
5
C ATHOLIC U NIVERSITY OF L EUVEN, Leuven, Belgium
The dose delivery techniques for patients undergoing radiation therapy are
evolving rapidly and newer modalities are brought into clinical use yearly.
It is clear that these new emerging techniques provide an opportunity to deliver more precise and accurate treatments as well as take advantage of adifferent (read better) biological effectiveness of newer modalities. The treatment techniques are optimized to deliver the largest amount of dose to thetarget volume while the surrounding tissues are maximally spared. This increases the effectiveness and reduces the short term side effects. However,late effects due to the possible increase of the volume irradiated with a low
dose or the late effect of additional neutrons or heavier ion fragments has notbeen considered.
Currently, little or no studies are available providing evidence on the safety ofthese techniques, not in the least due to the short time span available. In order to estimate the benefits and possible risks of new techniques we can only
rely on measurement and risk analysis, furthermore to assess the impact inan objective manner it is imperative that correct information is available regarding the dose levels, as well as dose type delivered.
The high dose regions are well defined and predicted in planning software,
while the lower dose regions and the effect of scattered particles have received less attention.
In this paper we will present the methodology and results from measurements of out-of-field doses for newer techniques using photons (IMRT, Arc
treatment, and IGRT contributions), protons (neutrons), and heavy ions (neutrons, nuclear fragments). Finally, a comparison with the doses obtained fromcommercial and in-house planning systems is presented.
The research leading to these results has received funding from the European
Atomic Energy Community’s Seventh Framework Programme (FP7/20072011) under grant agreement n◦ 231965 ("ALLEGRO" project).

NTCP MODELLING: CURRENT MODEL DEVELOPMENT, FITTING,
VALIDATION, AND APPLICATIONS
H. Langendijk1 , K. Haustermans2 , E. Hug3 , K. Trott4
1

U NIVERSITY M EDICAL C ENTER G RONINGEN, Groningen, Netherlands
U NIVERSITY H OSPITAL G ASTHUISBERG, Leuven, Belgium
PAUL S CHERRER I NSTITUTE (PSI), Villigen - PSI, Switzerland
4
U NIVERSITA DEGLI S TUDI DI PAVIA, Pavia, Italy23

Normal Tissue Complication Probability (NTCP) models describe the relationship between radiation dose distribution parameters and the probabilityof a given side effect. Until recently, the classical approach of such models
only included univariate associations. Moreover, The LKB, critical element,
critical-volume and relative-seriality models are exclusively based on the dose
distribution in a single organ. Clinical complications and even damage to single organs, however, are usually the result of dose to multiple organs. The
formulation of these models does not generally facilitate accounting for this
and/or the inclusion of other factors. In the ALLEGRO project, we therefore
used a multivariate logistic regression model. Establishing the optimal combination of predictors resulting in the most accurate prediction of normal tissue
toxicity is, however, not trivial. The development of such models includes 1)
determining which parameter combinations result in a good description of thedata, 2) determining the number of parameters that can be supported by thedata without over-fitting, and 3) determining the robustness of parameter selection.
Most published NTCP-models have not been validated in independent external validation data sets. An important finding in the ALLEGRO project wasthat some NTCP-models developed among patients treated with 3D-CRT
showed markedly lower performance when applied among patients treatedwith IMRT. The lower performance can be explained by difference in casemix, over fitting and the existence of so-called "hidden" factors that may become more important if the dose to certain organs at risk are reduced dueto the new radiation techniques. Therefore, external validation is an essential
and necessary step before a model can be accepted when new techniques
are applied and generally implemented in clinical practice.
The development and validation of NTCP-models require large numbers ofpatients, preferably subjected to well structured and standardised prospective follow up programs.
The research leading to these results has received funding from the European
Atomic Energy Community’s Seventh Framework Programme (FP7/20072011) under grant agreement n◦ 231965 ("ALLEGRO" project).
125 speaker
SECOND CANCERS AFTER RADIATION THERAPY - POTENTIAL
AND PITFALLS OF THE ANALYSES OF CLINICAL DATABASES
W. Dörr1 , D. Bartkowiak2 , T. Grantzau3 , B. A. Jereczek-Fossa4 , U.
Schneider51
T ECHNISCHE U NIVERSITÄT D RESDEN, Dresden, Germany
2
U NIVERSITY H OSPITAL U LM, Ulm, Germany
3
A ARHUS U NIVERSITY H OSPITAL, Aarhus N, Denmark
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Milan, Italy
5
PAUL S CHERRER I NSTITUTE (PSI), Villingen, Switzerland
The risk for radiotherapy-induced second cancers in adult cancer patients is
estimated to be low, at a few percent (with large uncertainties). Hence, thisrisk is comparable to the usually accepted incidence of severe late normal
tissue complications. Clinical data suggest that second cancers are likely tooccur in the regions near the high-dose treatment volume, i. e. the field margins, as well as at distant sites in low-dose volumes. Besides direct cancer
induction by ionising irradiation through malignant transformation of cells, induction of second cancers (in high-dose volumes) can occur indirectly, basedon radiation-induced chronic hyperproliferative inflammatory processes that
represent pre-cancerous lesions. This introduces a deterministic component into the stochastic nature of cancer development after radiation exposure. Hence, the dose-risk relationship of second cancers after radiotherapy
is highly complex. With new treatment modalities such as highly conformal
photon or particle therapy, the dose distribution within the patient changes
substantially compared to conventional radiotherapy techniques, potentiallyassociated with a considerable change in the risk for second tumours.
Confounding factors must be considered for dose-risk analyses of second
cancers. Besides an individual predisposition of the patient, persisting exposure to the initial carcinogen, but also additional chemotherapy or administration of "biologicals" may play a crucial role.
It is essential to quantify and predict this risk for existing and evolving treatment modalities, respectively, as a basis for an optimal choice of treatment. In
the present project, institutional and other databases and registries of second
cancers were evaluated for the availability and accessibility of sufficiently detailed data on patient-related factors, radiotherapy parameters, and additional
therapies. Examples will be presented.
Options for reconstruction of radiation dose and dose distributions, both inlow-dose and high-dose volumes, in relation to the site of the origin of a second tumour, based on patient files and existing documentation in the individ-

S YMPOSIUM

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ual institutions included in the study, were assessed. Dose reconstruction bytreatment planning systems and dose reconstruction software (PERIDOSE)
was compared to physical measurements of the dose distribution close to
and remote from the treatment volume. For second cancer dose-risk analyses, relevant patient factors need to be identified (e. g. age, gender, site of
the primary tumour). In parallel, models to describe the dose dependence of
second cancer risks have to be designed and validated with the data available
from the databases.
Results from the second cancer studies within the ALLEGRO project will bepresented and discussed, and the requirements with regard to clinical documentation and databases, as well as to procedures for dose reconstruction
will be addressed.
The research leading to these results has received funding from the European
Atomic Energy Community’s Seventh Framework Programme (FP7/20072011) under grant agreement n◦ 231965 ("ALLEGRO" project).
126 speaker
CONCLUSIONS AND RECOMMENDATIONS: LESSONS LEARNEDFOR CLINICAL PRACTICE, POLICY MAKERS, EQUIPMENTMANUFACTURERS, PROSPECTIVE DATA COLLECTION, AND
QUESTIONS REMAINING FOR FUTURE RESEARCH
M. Baumann1 , U. Koch1 , D. Kunath1 , W. Enghardt1
1
T ECHNISCHE U NIVERSITÄT D RESDEN, Dresden, Germany
The population of surviving cancer patients treated with radiation therapy isincreasing. This leads to the fact that long term harmful effects of the radiation
to normal tissue become more evident. In particular for children and adolescents the survivorship period may be many decades. It is important to note,that these cancer survivors today constitute one of the largest groups of European citizens for which detailed health epidemiology data are urgently neededfor developing state of the art strategies for providing treatments which efficiently control the tumour but have a low risk of radiation induced sequelae.
The different work packages of the ALLEGRO project address a spectrumof topics relevant for the risk of early and late radiation damage to normal
tissues and for tumour induction including both, conventional treatment techniques and emerging techniques like protons and heavy ions. The ALLEGRO
project reviews the current state of knowledge to identify issues which need
to be addressed in future investigations or in recommendations.
Here we will review results of different work packages of the ALLEGRO consortium and deduct recommendations for clinical practice, policy makers,
equipment manufacturers, prospective data collection and future research inthis field.
The research leading to these results has received funding from the European
Atomic Energy Community’s Seventh Framework Programme (FP7/20072011) under grant agreement n◦ 231965 ("ALLEGRO" project).

New frontiers in metastatic cancers - Session developed in collaboration with ASCO and ESMO
127 speaker
NEW THERAPEUTIC TARGETS FOR ADVANCED LUNG CANCEREGFR AND EML4/ALK
J. C. Soria1
1
I NSTITUT G USTAVE R OUSSY, Villejuif, France
Lung cancer is the leading cause of cancer-related deaths worldwide NSCLC
is currently being revisited on the basis of molecular portraits that have leadto the identification of new molecular subtypes.
Larges scale studies have identified frequent mutation mainly in TP53, RB1,
CDKN2A, and STK11 tumor suppressor and in EGFR, KRAS and NRAS
oncogenes. Many other molecular abnormalities have been reported atlower frequencies in genes such as PI3K, PTEN, AKT1, MDM2, APC, FGFR,
HER2, KDR, MET, CTNNB1, ATM, BRAF, AKT1 and more recently ALK&. The most frequent kinase mutations were identified in EGFR receptor, atarget of many recently developed molecules, in 10 to 20% of NSCLC. The
majority of EGFR mutations occurred in exon 19 (small deletion) or in exon
21 (single point mutation, L858R). These activating mutations are associatedto responsiveness to tyrosine kinase inhibitors. On the other hand, several
mutations in exon 20 (T790M or small insertion) seem to confer resistance tosuch treatments. Patients harbouring EGFR mutation are highly sensitive to
EGFR inhibitors, that have demonstrated a PFS advantage when compared
to standard chemotherapy in the front-line setting.
Epidemiologic characterization of EML4-ALK translocations is ongoing but it
seems to be a rare aberration, most common in non-smokers or light-smokers
with the adenocarcinoma subtype of NSCLC (and signet ring features) , forming a distinct subgroup from patients harbouring EGFR, KRAS, mutations.
The frequency of EML4-ALK fusion transcripts is around 5% or less in Caucasians patients. Crizotinib (PF-02341066) is an ALK and MET inhibitor thathas demonstrated outstanding activity in monotherapy in patients with EML4-

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S YMPOSIUM

ALK translocations: 57% objective response in 82 patients with a median duration of treatment of 5,7 months and a predicted 67% PFS rate at 6 months.
Many other abnormalities linked to tyrosine kinase receptors could be used
for selection of specific therapy such as amplification or activation mutation of
HER2, HER3, HER4, FGFR 1, FGFR2, KDR&
128 speaker
IMPROVING THE OUTCOME WITH CURATIVE HIGH PRECISIONRADIOTHERAPY FOR METASTATIC PATIENTS?
E. Lartigau
Abstract not received.

M ONDAY, M AY 9, 2011
response to radiation and CTLA-4 blockade. Clin Cancer Res. 2009 Jan
15;15(2):597-606.
6. Matsumura S, et al. Radiation-induced CXCL16 release by breast cancer
cells attracts effector T cells. J Immunol. 2008 Sep 1;181(5):3099-107.
7. Dewan MZ, et al. Fractionated but not single-dose radiotherapy induces animmune-mediated abscopal effect when combined with anti-CTLA-4 antibody.
Clin Cancer Res. 2009 Sep 1;15(17):5379-88.
130 speaker
CAN SMALL DOSES OF RADIATION ENHANCE CHEMOTHERAPYIN ADVANCED PATIENTS?
V. Valentini1
1
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Radiation Oncology, Roma, Italy

129 speaker
ABSCOPAL IMMUNE RESPONSE LINKED TO RADIOTHERAPY
S. Formenti1
1
N EW YORK U NIVERSITY S CHOOL OF M EDICINE, New York, NY, USA
Over the past ten years we have developed a clinical translational program
based on the rationale of immunizing patients against their own tumor byconcomitantly: 1) removing existing "breaks" in their immune system and, 2)
harnessing local RT-induced physical and biological perturbations at the irradiated tumor site, to achieve the successful conversion of the original tumor
into an immunogenic hub (1, 2).
To mimic the common clinical setting of established, metastatic cancer, wehave employed as a model the poorly immunogenic 4T1 mouse mammary
carcinoma. After s.c. inoculation 4T1 cells grow to form a highly invasive
primary tumor that early on sheds spontaneous metastases to the lungs,
and other organs (3). Mice usually die of metastatic disease to the lungs.
9H10 mAb against CTLA-4 releases a negative regulator of T cell activation. We demonstrated the effects of combining RT with CTLA-4 blockade
given two weeks after implantation in mice, when primary tumors are palpable and metastatic cells have already spread systemically (4). Whereas single modality treatment was ineffective, RT and CTLA-4 blockade elicited CD8
T-cell-dependent antitumor immunity. The immune response effectively inhibited the growth of spontaneous lung metastases prolonging the survival timeof animals. However, cure was rare, and most mice eventually succumbed totheir disease (4). In the same models we found that RT enhanced the secretion by cancer cells of CXCL16, a chemokine that binds to CXCR6 on Th1
and activated CD8 effector T cells, and mediates their recruitment to sites
of inflammation. CXCR6-deficient mice showed reduced infiltration of tumors
by activated CD8 T cells and impaired tumor regression after RT and 9H10(5). The contribution of invariant natural killer T (iNKT) cells, a subset withunique regulatory functions, in the response to RT and CTLA-4 blockade wasthen investigated. Growth of 4T1 primary tumors and lung metastases wascompared in wild type (WT) and iNKT cells-deficient (iNKT/) mice, resulting
in long-term survival, and resistance to a challenge with 4T1 cells (6).
In preparation to a clinical translation of these findings we hypothesized thatthe type of dose fractionation regimen determines the ability of radiotherapy
to synergize with antiCTLA-4 antibody. Using TSA mouse breast carcinoma
and MCA38 mouse colon carcinoma models, cells were injected s.c. intosyngeneic mice at two separate sites, defined as a "primary" site that wasirradiated and a "secondary" site outside the radiotherapy field. Mice wererandomly assigned to eight groups receiving no radiotherapy or three distinct
regimens of radiotherapy (20 Gy in a single fraction, 8 Gy in 3 fractions, or
6 Gy in five 5 fractions, on consecutive days), +/- 9H10. In neither of thetwo models tested, treatment with 9H10 alone had detectable effect. Eachof the radiotherapy regimens caused comparable growth delay of the primarytumors but had no effect on the secondary tumors, outside the radiation field.
Conversely, 9H10 with either fractionated RT regimens (but not with single
dose RT) achieved enhanced tumor response at the primary and secondarysite (P < 0.0001). The frequency of CD8+ T cells showing tumor-specific IFNgamma production was proportional to the inhibition of the secondary tumor(7).
The findings on dose and fractionation were translated to a preclinical experiment, that tests the combination of radiotherapy and fresolimumab, a monoclonal antibody against TGFβ . A clinical trial to test this combination inmetastatic breast cancer is ongoing, aiming at detecting abscopal responses
in metastases outside the radiation field.
1. Demaria S, Bhardwaj N, McBride WH, Formenti SC. Combining radiotherapy and immunotherapy: a revived partnership. Int J Radiat Oncol Biol Phys
2005;63:655666.
2. Formenti SC, Demaria S. Systemic effects of local radiotherapy. Lancet
Oncol. 2009 Jul;10(7):718-26.
3. Aslakson CJ, Miller FR. Selective events in the metastatic process definedby analysis of the sequential dissemination of subpopulations of a mouse
mammary tumor. Cancer Res 1992;52:13991405.
4. Demaria S et al. Immune-mediated inhibition of metastases following treatment with local radiation and CTLA-4 blockade in a mouse model of breast
cancer. Clin Cancer Res 2005;11:728734.
5. Pilones KA, et al. Invariant natural killer T cells regulate breast cancer

Improvements in the methodology of clonogenic assays within the last decade
have made it possible to observe that the efficacy in killing clonogenic cells ofradiation doses below 0,5 Gy is larger than predicted by the linear quadraticmodel for a variety of tumour cell lines in vitro. In other words, radiation
doses below 0,5 Gy seems to be more effective per unit dose than higher
doses. This phenomenon is known as "Low Dose Hyper-Radio Sensitivity" (LD-HRS). Low-dose radiotherapy (LDR) (<50 cGy) induces enhanced
cell killing in vitro via the hyper-radiation sensitivity phenomenon. The exact
molecular mechanisms underling the HRS phenomenon is still unclear.
LD-FRT has been demonstrated to enhance the effectiveness of multiple
chemotherapeutic agents, including Carboplatin, Cisplatin, Docetaxel, Etoposide, Gemcitabine and Paclitaxel, across a variety of tumor cell lines. Even
if the outcome of clinical results with only LD-FRT are controversial, preliminary results of clinical trials combining LD-FRT with chemotherapy suggestthat this treatment could be both feasible and effective. Although far from being conclusive, these first evidence are promising and support the opportunityof further phase II studies exploring LD-FRT with concurrent chemotherapy
as a new treatment modality.

M ONDAY, M AY 9, 2011

Proffered paper
Clinical Proffered Papers 1: Head and Neck131 oral
THE INFLUENCE OF COMORBIDITY, SMOKING BEHAVIOUR
AND HUMAN PAPILLOMAVIRUS ON OVERALL SURVIVAL IN 1091
PATIENTS WITH OROPHARYNGEAL CARCINOMA: THE DAHANCA
EXPERIENCE
C. R. Boeje1 , P. Lassen1 , C. Hoff1 , J. Overgaard1
1

A ARHUS U NIVERSITY H OSPITAL, Department of Experimental ClinicalOncology, Aarhus C, Denmark
Purpose: Cigarette smoking is a well known risk factor for head andneck squamous cell carcinoma (HNSCC). Besides the carcinogenesis effect,
smoking is also associated with other systemic comorbidities such as pulmonary and cardiovascular diseases. During the past 30 years the incidenceof oropharyngeal carcinomas (OC) in the Western world has increased andHuman papillomavirus (HPV) seems to be the predominant cause. In thesame period, a decrease in smoking has led to a decline in the incidence of
HNSCC at other sites than the oropharynx. Due to demographic changes, thegeneral population becomes older and consequently more HNSCC patients
may suffer from comorbidity. The purpose of this study was to investigate
the impact of comorbidity, smoking behaviour and tumour HPV-associatedp16-status on overall survival (OS) in patients with OC treated with primaryradiotherapy (RT).
Materials: The DAHANCA database contains information on all HNSCCpatients in Denmark from 1971 to 2006 (17.784 patients). Complete dataon comorbidity, smoking behaviour and p16-status was available for 1091
patients with OC treated with primary RT. Information on comorbidity prior
to diagnosis of HNSCC was obtained from the National Patient Registrywhich contains discharge diagnoses from all hospital admissions and outpatient visits in Denmark. This data was adapted to the Charlson Comorbidity Index (CCI). Information on current smoking status and pack-years was
included in the DAHANCA-forms Evaluation of HPV-status was done by p16immunohistochemistry, and tumours were classified as either p16-positive or
negative.
Results: In total 18% of patients had CCI-score 2+. Median age was 61 yrs
and 74% were males. 64% were current smokers with a median of 37 packyears. There was no significant difference in CCI score between genders.
5% of HPV-pos patients had CCI-score 2+ compared to 21% in the HPV-neg
group. In univariate analysis OS was significantly improved for patients without comorbidity (5-year actuarial values 53% vs 38%, p<0.001), non-smokers
during RT (66% vs 39%, p<0.001) and HPV-positivity (58% vs 28%, p<0.001),
respectively.In a Cox proportionate multivariable analysis risk of death was independently associated with comorbidity (HR=1.38 [95% C.I:1.14-1.67]), current smoker status (2.11[1.68-2.65]), number of pack-years (1.01[1.00-1.01]),
HPV-positivity (0.38 [0.23-0.60]), advanced T-stage (1.90[1.58-2.29]), nodal
disease ( 1.71 [1.42-2.06]), and age >60 years (1.40[1.16-1.69]).
Conclusions: Treatment outcome for OC not only depends on the extent ofcancer disease at time of diagnosis, but is also strongly influenced by comorbidity, smoking habits and tumour HPV status. Optimisation of comorbidity
and avoidance of smoking may add to improve efficacy of treatment.
132 oral

EXPRESSION OF THE EPIDERMAL GROWTH FACTOR PREDICTS
THE EFFECT OF HYPOXIA MODIFICATION AS AN ADDITIVE TOACCELERATED RADIOTHERAPY OF LARYNGEAL CANCER IN ARANDOMIZED TRIAL
M. Nijkamp1 , P. Span1 , I. Hoogsteen1 , C. Terhaard2 , P. Doornaert3 , H.
Langendijk4 , P. van den Ende5 , A. Chin6 , A. van der Kogel1 , J. Bussink1 , J.
Kaanders1
1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Radiation Oncology,
Nijmegen, Netherlands
2
U.M.C. U TRECHT, Radiation Oncology, Utrecht, Netherlands
3
VU U NIVERSITY M EDICAL C ENTER, Radiation Oncology, Amsterdam,
Netherlands
4
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Oncology, Groningen, Netherlands
5
MAASTRO CLINIC, Radiation Oncology, Maastricht, Netherlands
6
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Clinical Oncology,
Leiden, Netherlands
Purpose: The Epidermal Growth Factor Receptor (EGFR) is frequently overexpressed in laryngeal carcinomas. Activated EGFR leads to activation ofvarious signaling pathways and transcription of genes responsible for a reduced response to radiotherapy resulting in a decreased local-regional control and survival. New treatment methods to reduce this resistance to radiotherapy are an active field of research. One new treatment method is Accelerated Radiotherapy with CarbOgen and Nicotinamide (ARCON), whichcounteracts enhanced tumor cell proliferation and reduces intratumoral hypoxia. The purpose of this study was to investigate the predictive value of

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EGFR for ARCON in patients with laryngeal carcinoma.
Materials: 345 patients with advanced stage laryngeal carcinoma wererandomized between accelerated radiotherapy alone and ARCON. Paraffinembedded biopsies from these patients were processed for immunohistochemical staining of EGFR. The relative tumor area positive for EGFR (EGFR
fraction) was quantitated with automated image analysis and related to clinical outcome.
Results: A large variation was observed in EGFR fraction between tumors
with expression levels ranging from 0-0.93 (median fraction 0.4). Patientswith tumors with low EGFR expression treated with ARCON had a significantly better 5-year loco-regional control (88%) and disease-specific survival(91%) versus patients with high EGFR expressing tumors (71% and 78 % respectively). No difference between high and low EGFR expression was foundin the accelerated radiotherapy arm.
Conclusions: EGFR fraction is a significant predictive value for tumor response to ARCON treatment. Low EGFR expressing tumors benefit fromtreatment with hypoxia modification in addition to accelerated radiotherapy.
133 oral
DIAGNOSTIC PERFORMANCE OF FDG-PET(CT) FOR POSTTREATMENT RESTAGING OF HEAD-NECK CANCERS: A METAANALYSIS
T. Gupta1 , Z. Master1 , S. Kannan2 , J. P. Agarwal3 , S. Ghosh-Laskar3 , V.
Rangarajan4
1
ACTREC, TATA M EMORIAL C ENTRE, Radiation Oncology, Navi Mumbai,
India
2
ACTREC, TATA M EMORIAL C ENTRE, Epidemiology and Biostatistics, Navi
Mumbai, India
3
TATA M EMORIAL H OSPITAL, Radiation Oncology, Mumbai, India
4
TATA M EMORIAL H OSPITAL, Nuclear Medicine PET-CT, Mumbai, India
Purpose: To conduct a systematic review and meta-analysis of studies assessing the diagnostic performance of FDG-PET(CT) in post-treatment response assessment and/or surveillance imaging of head neck squamous cell
carcinoma (HNSCC).
Materials: Systematic literature search to identify potentially relevant studies.
Standardized metrics of diagnostic test accuracy viz. sensitivity, specificity,
positive predictive value (PPV), and negative predictive value (NPV) usedfrom individual studies and combined using random effects model to estimate weighted mean pooled estimates with 95% confidence intervals (CI).
Subgroup analysis was done for impact of timing of PET scan on diagnostic
performance.
Results: A total of 51 studies involving 2335 patients were included in themeta-analysis. The weighted mean (95%CI) pooled sensitivity, specificity,
PPV, and NPV of post-treatment FDG-PET(CT) for the primary site was
79.9% (73.7-85.2%), 87.5% (85.2-89.5%), 58.6% (52.6-64.5%), and 95.1%(93.5-96.5%) respectively. Similar estimates for the neck were 72.7% (66.678.2%), 87.6% (85.7-89.3%), 52.1% (46.6-57.6%), and 94.5% (93.1-95.7%)
respectively. Scans done ≥12 weeks after completion of definitive therapy
had moderately higher diagnostic accuracy on meta-regression analysis using time as a covariate.
Conclusions: The overall diagnostic performance of post-treatment FDGPET(CT) for HNSCC is good, though its PPV is somewhat suboptimal. Its
NPV remains exceptionally high with a negative post-treatment scan highlysuggestive of absence of viable disease with potential to guide therapeutic
decision-making. Timing of post-treatment imaging has a significant, thoughmoderate impact on diagnostic accuracy.
134 oral
XEROSTOMIA PATIENT REPORTED OUTCOMES ARE A LINEAR
FUNCTION OF CONTRALATERAL PAROTID GLAND MEAN DOSE
Z. Saleh1 , W. Thorstad2 , A. Apte1 , J. Deasy1
1
M EMORIAL S LOAN -K ETTERING C ANCER C ENTER, Department of Medical
Physics, New York, USA
2
WASHINGTON U NIVERSITY S CHOOL OF M EDICINE, Department ofRadiation Oncology, St. Louis, USA
Purpose: To better understand the impact of head and neck radiotherapy
dose-distribution parameters on stimulated parotid gland function as measured by xerostomia-related patient reported outcomes (PROs).
Materials: From September 2006 to May 2009, 113 patients with head andneck cancer were treated at Washington University School of Medicine in St.
Louis using intensity modulated and conventional radiotherapy. As part of an
IRB-approved protocol, patients filled out a xerostomia-related questionnaireof 28 questions prior to radiotherapy and at several time points after treatment. The questions most relevant to this analysis all refer to "the level ofdifficulty" during chewing/swallowing/dryness of the throat while eating. Patients gave discrete scores from 0 to 10 where 10 denotes the greatest possible difficulty and 0 denotes no difficulty. Analysis included only those patients
who completed the questionnaire before as well as after treatment, at a time
point of approximately 16 months post-RT (median 15.77 mos., range 12-22

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P ROFFERED PAPERmos.). Out of 83 patients with available data, 26 patients were treated withradiation alone while 57 received concurrent chemotherapy. Treatment plansfor RT-alone patients were extracted using the Computational Environment forRadiotherapy Research (CERR) to be further analyzed. Univariate and multivariate linear analysis was used to evaluate the relation between the PROsscores and different treatment factors including mean dose to the contralateral and ipsilateral parotid glands, age, gender, chemotherapy, and surgery.
Results: PROs scores at 16 mos. post-RT, for those treated with radiation
alone, have a linear correlation to the mean dose of the contralateral parotid
gland, as illustrated in the figure, which plots responses to two questions:"Rate your difficulty in chewing" and "Rate your difficulty in swallowing solidfood" due to the dryness of the mouth. In both cases, the PRO scores increased linearly (1.2% or 1.8% per Gy for chewing/swallowing respectively),over a dose range from 5 Gy to 30 Gy mean dose to the contralateral parotid
gland. Error bars on the plot represent estimated standard deviations of themean. Surprisingly, patients treated concurrently with chemotherapy (usually
started prior to the first questionnaire) typically already had increased PROs
toxicity scores.

M ONDAY, M AY 9, 2011
larynx after a period 60 months average. We evaluated their voice using
the Voice Handicap Index 30 (VHI 30) scale. Impact on global quality of life
and on feeding difficulties was evaluated using the EORTC Quality of Life
Questionnaire - Core 30 (EORTC QLQ-C30) and the Quality of Life Headand Neck Module (QLQ-H&N35).
Results: LED-FS was seen in 28% of the overall population, with significant
benefits in favour of the TPF arm (36%) compared with the PF arm (21%)(p=0.007). Analysis of functional scores for the 61 patients (91%) completing the questionnaires revealed 15% severe speech handicap of cases andin 20% of cases regarding to feeding. Eight percent of patients used a feeding tube, 3% had undergone tracheostomy, and 27% of patients used food
diet. The results were superior in the TPF arm compared with the PF arm regarding pain symptoms and use of food diet. The main criterion determining
voice quality was the existence of laryngeal remobilisation according to themultivariate analysis.
Conclusions: Our updated showed that successful larynx preservation at
5 years was significantly better in the TPF arm (36%) than in the PF arm(21%) based on a new global evaluation criterion that takes into consideration
survival, control of the disease and laryngoesophageal function. Functional
handicap in terms of phonation and swallowing was low overall in the population analyzed. These data may serve as reference tools for comparison of
future larynx preservation trials and must be collected prospectively.
136 oral
RISK FACTORS FOR SWALLOWING DYSFUNCTION AFTER RADIOTHERAPY IN THE DAHANCA 6 & 7 RANDOMIZED TRIAL
H. R. Mortensen1 , K. Jensen1 , J. Overgaard1 , L. Specht2 , M. Overgaard1 ,J. Johansen3 , J. F. Evensen4 , E. Andersen5 , L. J. Andersen6 , H. S.
Hansen2 , C. Grau1
1
A ARHUS U NIVERSITY H OSPITAL, Aarhus C, Denmark
2
T HE F INSEN C ENTER - R IGSHOSPITALET, Copenhagen, Denmark
3
O DENSE U NIVERSITY H OSPITAL, Odense, Denmark
4
DNR - N ORWEGIAN R ADIUM H OSPITAL, Oslo, Norway
5
U NIVERSITY H OSPITAL H ERLEV, Herlev, Denmark
6
A ALBORG S YGEHUS S YD, Aalborg, Denmark

Conclusions: Consistent with other published results, an increasing meandose to the contralateral parotid gland correlated significantly with increased
xerostomia symptoms. This was true even for mean doses well below thetypical quoted values of 28-39 Gy for severe xerostomia. Thus, reducing
contralateral parotid gland mean doses is probably beneficial to the patient, atleast down, although the effective dose response slope is very shallow. This
research was supported by NIH R01 grant CA85181 and ARRA supplement.
135 oral
LONG TERM RESULTS OF THE GORTEC 2000-01 LARYNX
PRESERVATION RANDOMIZED TRIAL USING A COMPOSITEFUNCTIONAL ENDPOINT
Y. Pointreau1 , C. Debelleix2 , P. Garaud1 , S. Chapet1 , C. Sire3 , C. Tuchais4 ,J. Tortochaux5 , S. Faivre6 , S. Guérif7 , M. Alfonsi8 , G. Calais2
1
H ENRY K APLAN C ENTER , C ENTRE H OSPITALIER R ÉGIONAL U NIVERSI TAIRE , Tours, France
2
C ENTRE H OSPITALIER R ÉGIONAL U NIVERSITAIRE, Tours, France
3
CHBS L ORIENT, Lorient, France
4
CRLCC PAUL PAPIN, Angers Cedex 01, France
5
C ENTRE J EAN P ERRIN, Clermont Ferrand, France
6
I NSTITUT G USTAVE R OUSSY, Villejuif, France
7
H ÔPITAL J EAN B ERNARD, Poitiers, France
8
I NSTITUT S AINTE C ATHERINE, Avignon - Cedex 02, France
Purpose: Induction chemotherapy with taxanes (ICT) followed by radiotherapy can be proposed for an increasing number of patients for larynx preservation in locally advanced head and neck squamous cell carcinoma. However,anatomical preservation is not necessary synonymous with sparing functions(phonation and swallowing). On completion of the GORTEC 2000-01 larynx
preservation trial (which compared TPF versus PF ICT), we updated results
focus on laryngoesophageal dysfunction-free survival (LED-FS) and evaluated the quality of voice and swallowing for patients undergoing conservative
therapy.
Materials: For the 213 patients initially included in the GORTEC 2000-01
study, we carried out a retrospective analysis of LED-FS in which therapeutic
failure is defined as the occurrence of death, local relapse, total or partial
laryngectomy, tracheostomy or use of a feeding tube at two years or more
after the end of treatment. We identified 66 patients still alive with an intact

Purpose: Dysphagia is a common and debilitating side effect in head andneck radiotherapy (RT). The aim of this report was to establish a multivariate
predictive model for acute and late dysphagia after RT, based on informationfrom a large prospective trial.
Materials: The DAHANCA 6&7 randomized phase-III study included 1,476
patients with squamous cell carcinoma of the head and neck eligible for primary RT alone. Patients were randomized between 5 or 6 weekly fractions ofconventional RT, and received 66-68 Gy in 33-34 fractions. If non-glottic cancer Nimorazole was administered. Patients were seen weekly during treatment and at regular intervals until 5 years after treatment. Prospective morbidity recording were available from 1,468 patients.
Results: Acute dysphagia according to DAHANCA grades 1, 2, 3 and 4 occurred in 83%, 71%, 43% and 23%, respectively. Severe dysphagia, definedas "taking liquid food only" or worse (grade 3 or 4) occurred in 47% and
38% of patients receiving accelerated or conventional radiotherapy, respectively (p=0.001). At 1,2,3,4 and 5 years, the prevalence of chronic dysphagia
greater than grade 0, was 46%, 32%, 29%, 24%, 23 %, respectively with nodifference between 5 and 6 fractions.In a multiple logistic regression analysis, the following factors were significant independent factors for severe acutedysphagia: T3-T4 tumors, N-positive, non-glottic cancer, age>62 years, baseline dysphagia > 1 and accelerated radiotherapy.The following factors were
prognostic factors for late dysphagia: non-glottic cancer and baseline dysphagia > 1.
Conclusions: Predictive models were established to characterize patients
who were at risk of developing acute or late dysphagia after RT in the DAHANCA 6&7 trial. The results may be useful to identify patients who could
benefit from prophylactic measures against swallowing dysfunction.The study
is been supported by the Danish Cancer Society. Aarhus University Hospital,
Copenhagen University Hospital, Herlev Hospital, Odense University Hospital, Aalborg Hospital - on behalf of DAHANCA, the Danish Head and Neck
Cancer Group.

M ONDAY, M AY 9, 2011
137 oral
ARE ALL TECHNIQUES ALIKE? A COMPARISON OF THREEROTATIONAL IMRT TECHNIQUES FOR HEAD-AND-NECK CANCER.
Y. Boukour1 , O. De Hertogh2 , R. Ruchaud3 , R. Vanderstraeten4
1
C.H. P ELTZER - L A TOURELLE, Medical Physics, Verviers, Belgium
2
C.H. P ELTZER - L A TOURELLE, Department of Radiotherapy, Verviers,
Belgium
3
C ENTRE P RIVÉ DE R ADIOTHÉRAPIE DE M ETZ, Medical Physics, Metz,
France4
VARIAN M EDICAL S YSTEMS, Medical Physics, Diegem, Belgium
Purpose: For treating HNC, rotational IMRT easily respects dose constraints
for PTV coverage and for parotid gland sparing. However, it raises new issues regarding the dose delivered to the non-tumour tissue (NTT) outside the
PTV and the integral dose. The purpose of this study is:- to compare threerotational IMRT techniques, i.e. Hi-ART (TomoTherapy Inc.), RapidArc (Varian Medical Systems Inc.) and VMAT (Elekta AB), in the setting of HNC.- toassess differences in terms of dose homogeneity within the PTV, dose conformity to the PTV and dose containment outside the target volume. - to calculate the integral dose delivered.- to compare the ability of these techniquesto spare the OAR.
Materials: Locally-advanced HNC cases (T3-4, N2-3) were randomly selected in the database of our centre. Contours were delineated according to the DAHANCA-EORTC-GORTEC-RTOG consensus and were peerreviewed. DICOM studies were sent to three different physicists, each having
a significant expertise in one of the investigated rotational techniques. Six
plans were performed by each physicist, to a 50 Gy prophylactic dose and70 Gy therapeutic dose, both in 2Gy-fractions. RapidArc and VMAT were
calculated using a 2-arc delivery technique. Plans were returned to the coordinating centre and compared using the ArtiView software (AquiLab SAS).
Results: 1. Regarding dose homogeneity to the PTV, RapidArc increases
PTV underdosage by 10% and overdosage by 7% compared to Hi-ART.
VMAT increases PTV underdosage by 24% and overdosage by 18%.2. Dose
conformity to the PTV is quantified by the Overlap Ratio (OR) and the Dice
Similarity Coefficient (DSC): high OR and DSC values indicate a high conformity of the reference isodose to the PTV contour. Compared to Hi-ART,
RapidArc increases the OR and DSC by 6%. VMAT decreases the OR and
DSC by 4%.3. Dose containment outside the target volume is evaluated by
the Dose Gradient (DG), i.e. the sharpness of the dose fall-off in percent per
millimetre. Hi-ART, RapidArc and VMAT respectively achieve DG of 2.8, 2.5
and 1.9%/mm.4. Integral dose (ID) depends on both the dose conformity andon the dose fall-off. Compared to Hi-ART, RapidArc achieves similar ID to
the patient and NTT. VMAT increases ID by 10%.5. Regarding OAR, RapidArc increases the dose to the parotid gland by 2.5 Gy and VMAT by 4 Gy,compared to Hi-ART.
Conclusions: In the present study, Hi-ART ensured a more homogeneous
dose delivery to the PTV and a better OAR sparing compared to the linacbased 2-arc delivery techniques. However, differences between Hi-ART and
RapidArc were small, whereas larger differences were observed with VMAT.
Dose unnecessarily delivered to the NTT is confirmed to be a challenge, as
VMAT increased the ID by 10% compared to Hi-ART and RapidArc. The
present study showed the importance of new evaluation parameters such as
the OR, DSC and DG to assess IMRT plan quality and ID. Further rotational
technique comparisons and trials should encompass these parameters.

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Symposium
Intra-fraction challenges - Equipment
138 speaker
NEW TECHNOLOGIES FOR THE MANAGEMENT OF ORGAN
MOTIOND. Verellen
Abstract not received.

139 speaker
RADIOTHERAPY SYSTEMS WITH INTEGRATED MRI FUNCTIONALITY FOR DIRECT, INTRA-FRACTION TUMOUR TRACKING
B. Raaymakers1 , J. Lagendijk1 , M. Stam1 , S. Crijns1 , K. Smit1 , M. van
Vulpen1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands

1

Integrated MRI radiotherapy systems promise to visualize soft-tissue structures in real-time during radiation delivery. This enables MRI guided radiotherapy with real-time feed-back directly on the tumour position and shapewithout the need for surrogates. Currently three hybrid MRI radiotherapy systems are under investigation: The 1.5 T MRI with a 6 MV accelerator from
UMC Utrecht, The Netherlands, in collaboration with Elekta and Philips, the
0.2 T MRI with a 6 MV accelerator from the Cross Cancer Institute, Canada
and the 0.35 T MRI with 3 60Co sources from ViewRay, U.S.A. It has beenshown that simultaneous MR imaging and radiation delivery is feasible andclinical prototypes are upcoming.
The dynamics of anatomic motion range from daily patient positioning variations, to rectal and bladder filling and peristalsis on a scale of minutes, tobreathing related motion and unintended patient motion on a scale of seconds. The aim of this work is to illustrate the possibilities of the hybrid MRI
radiotherapy systems for tracking intra-fraction motion at various time scales,
for sites such as prostate, cervix, rectum, kidney, liver and lung. A relatively
straightforward approach of tracking is using the MRI as a watchdog for motion, f.i. 50 Hz 1D MRI to monitor stability of a kidney or lung tumour during a breath-hold. Similarly, such data can be used for gating purposes by
only delivering radiation when the tumour is within a pre-defined phase of thebreathing. Alternatively, this signal can act as a direct measure of the tumour
position to be used as an input for dynamic multi-leaf control. Another application is monitoring if the target is within pre-defined bounds/margins, e.g.
2.5 Hz 2D MRI of a representative slice through a cervical or rectal tumour.
Tracking deformation in 3D at 1 Hz can be done for example to detect contourchanges of the liver, but clearly plan adaptation on such changes are morechallenging than simple beam on/off strategies.
As in any MRI acquisition, the signal-to-noise ratio and the contrast-to-noise
ratio are related to the main magnetic field strength and are competing withspatial and temporal resolution. The MR imaging is the first step of intrafraction tracking, the interpretation of these data is the second step. The
challenge for real-time tracking is to define structures in the image that canbe tracked robustly while being representative for the motion monitoring ofinterest. The interplay between MR image quality and the image registration/segmentation used to detect the relevant structures will be discussed.
Fortunately tracking is helped by the fact that we have a daily optimised treatment plan based on an initial on-line MRI as the starting point for intra-fraction
correction. So the location and shape of the tumour is already (approximately)
known from the initial imaging. This makes tracking easier as automatic segmentation from scratch is far more complex than propagating pre-defined
contours from previous images. For instance intra-fraction cervical tumour
motion can be tracked using relatively simple grey-value based rigid registration whereas day-to-day variation can show complex deformations.
In conclusion, MRI can facilitate direct, real-time imaging of the target structures for image guided radiotherapy. For robust tracking the combination of
MRI sequences and the image processing step need to be optimised for eachspecific application.

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140 speaker
MARKER-BASED AND MARKER-LESS NAVIGATION IN CYBERKNIFE RADIOSURGERY
A. Schweikard1
1
U NIVERSITÄT L ÜBECK, Inst. For Robotics and Cognitive Systems, Lübeck,Germany
Purpose Tumors in the chest and abdomen move due to respiration. We
have developed the navigation methods for both marker-based and markerless Cyberknife radiosurgery. Based on this navigation, the Cyberknife robot
tracks a moving tumour in real time during a radiation treatment.To allow for
navigation, we must have an accurate sensor system which detects the current position of the target with very high precision. Our system relies on two
basic prinicples: correlation and prediction. We describe the technology behind both prinicples and relate these prinicples to inverse planning for the
Cyberknife.
Materials To track a moving tumor with the Cyberknife, the exact spatial position of the tumor must be determined in real-time. New sensor techniques
for measuring external motion are sufficiently fast and accurate to report motion of the patient’s skin surface. However, the target motion may not follow
the same direction as the external motion. Therefore external tracking of thepatient’s skin surface motion will generally not be sufficient for our purpose.
As an example, the skin surface may move in vertical direction, while thediaphragm may internally move in horizontal direction. Respiratory motion
patterns vary considerably between patients. Inhalation can result in a curve
motion that differs from the exhalation curve. Some sectors of the curve (exhalation) may be traversed faster than others (inhalation).
Based the Cyberknife robotic radiosurgery system, we combine stereo X-ray
imaging with infrared tracking. X-ray imaging is used as an internal sensor,
while infrared tracking provides information on the motion of the patient surface. While X-ray imaging gives accurate information on the internal target
location, it is not possible to obtain real-time motion information from X-ray
imaging alone. In contrast, the motion of the patient surface can be tracked
in real-time with commercial infrared position sensors. The central idea of
our approach is to use a series of images from both sensors (infrared and
X-ray) where image acquisition is synchronized . Thus, both X-ray image
pairs and infrared data have time-stamps From a series of sensor readings
and corresponding time-stamps, we can determine a motion pattern. Thispattern correlates external to internal motion, and is both patient- and sitespecific. the placement of an internal target tumor is then inferred from thepre-computed (and continuously updated) motion pattern.
We then modified the robot-based treatment mode of the Cyberknife brain
tumor protocol in such a way that respiratory motion can be compensated by
active motion of the robot. Thus, it is not necessary to gate the beam.
The system consists of the following components. A robot arm moves thelinear accelerator generating a 6 MV radiation beam. Infrared emitters areattached to a vest. An infrared tracking system records external motion of thepatient’s abdomen. An X-ray camera system (two X-ray cameras with nearly
orthogonal visual axes) records the position of internal gold markers.
The following approach to respiratory tracking was investigated. Prior to treatment, small gold markers visible in X-ray images are attached to the target organ. Stereo X-ray imaging is used during treatment to determine the precise
spatial location of the implanted gold markers via automated image analysis. Using stereo X-ray imaging, precise marker positions can be establishedonce every 10 seconds. This time interval is too long to accurately following
breathing motion.
In contrast, external markers (placed on the patient’s skin) can be tracked automatically with optical methods at very high speed. Updated positions canbe reported to the control computer more than 600 times per second.
Because neither internal nor external markers alone are sufficient for accurate tracking of lesions near the diaphragm, X-ray imaging is synchronizedwith optical tracking of external markers. The external markers are small active infrared emitters (IGT Flashpoint 5000, Boulder, CO.) attached to a vest.
Notice that the individual markers are allowed to change their relative placement. The first step during treatment is to compute the exact relationshipbetween internal and external motion, using a series of time-stamped snapshots showing external and internal markers simultaneously.
Although the infrared tracking is combined with X-ray imaging, it is not necessary to detect to position of the infrared emitters in an X-ray image. Timestamps permit the simultaneous positions of both marker types to be established, and can therefore be used to determine respiratory motion patterns.
These motion patterns are patient-specific, and can be updated during treatment.
To address the time lag from robot motion time, we use prediction. Henceto past history of the target motion is used to predict the future position by asmall amount of time into the future. This compensated for the time lag, andallows for enhanced tracking accuray.
While the methods (for both correlation and prediction) currently used in the
Cyberknife relied on straightforward methods from the literature, we have recently developed methods based on wavelet algorithms and support vector
machines.
Results We shown that the new methods for correlation and prediction give
substantially improved performance over the current clinical technologies.
Conclusions Robotic tracking of moving tumors can compensate for respiratory motion in radiosurgery. We have shown this for the case of Cyberknife

M ONDAY, M AY 9, 2011
radiosurgery. Since our approach results in improved treatment accuracy,such tracking should be considered in all radiosurgery and radiation therapy
applications.

M ONDAY, M AY 9, 2011

S YMPOSIUM

S 53

142 speaker

New developments and innovative approaches
141 speaker
PRE-CLINICAL ASSESSMENT OF RADIATION RESPONSE: TECHNOLOGY AND RESULTS FROM A SMALL ANIMAL IRRADIATIONFACILITY
J. Wong1 , P. Kazanzides2 , I. Iordachita2 , E. Ford1 , E. Tryggestad1 , M.
Armour1 , R. Jacques2 , R. Tuli1 , T. Deweese1
1
J OHN H OPKINS U NIVERSITY, Department of Radiation Oncology Molecular Radiation Sciences, Baltimore, MD, USA
2
J OHN H OPKINS U NIVERSITY, W HITING S CHOOL OF E NGINEERING,
Department of Computer Integrated Surgical Systems and Technology,
Baltimore, USA
Objective: Small laboratory animals are invaluable in pre-clinical studies.
For radiation therapy, the significant technological disparity between methods
used for human treatment and those for laboratory animal irradiation brings
into question the effectiveness of the latter to represent the clinical environment. In an effort to bridge the gap, we have constructed an advanced small
animal radiation research platform (SARRP) which mimics a human treatment machine.
Methods: The SARRP is a portable (i.e. with wheels), gantry mounted systemequipped with on-board x-ray cone-beam CT (CBCT) to guide focal irradiation. Conformal irradiation of a target is facilitated by a combination of gantry
rotation, from the vertical to 30o below the horizon, and robotic stages fortranslating and rotating the animal. One dual focus x-ray source is employed
for imaging and irradiation; the former with a 0.4mm focal spot operating at
65kVp to 100 kVp, the latter with a 3 mm focal spot operating at 225 kVp.
CBCT is acquired in a novel "pancake" geometry where the x-ray source andflat panel imager are stationary in their horizontal positions, while the study
animal is rotated between them. The pancake geometry allows CBCT imaging of up to 4 mice simultaneously, as well as their irradiation in one setting.
3D dose calculations based on the superposition-convolution method is implemented on a GPU to support 3D treatment planning in near real-time forsimple conformal irradiation. The open source 3D-Slicer software is employed
to support robotic navigation; target localization, image fusion, and robot positioning, for irradiation. Under CBCT guidance, the SARRP is capable ofdelivering radiation dose from beams ranging from 0.5 mm in diameter to 30
mm x 30 mm, to a target with accuracy of 0.2 mm. For beams larger than 1
mm in diameter, a dose rate of 2.5 Gy per min is achieved at the source toisocenter distance of 35 cm. In use for over 3 years, the system has enabledpreviously infeasible radiation studies with mice. These include studies of the
response of neural stem cells to focal irradiation in the brain and femur; thedisruption of the blood-tumor barrier due to focal irradiation, vaccine mediatedimmunotherapy in combination with radiation in orthotopic tumor models; theearly assessment of radiation induced lung toxicity.
Results: Results of several of these studies are maturing such as the arrest of neuronal stem cell migration with irradiation. Our experience has also
shown that localizing small soft tissue targets for irradiation is challenging
with x-ray CBCT imaging. The hurdle is particularly significant for the increasingly important class of small, pre-palpable, orthotopic, or spontaneous,tumor models growing in a normal tissue environment. We have thus initiated an effort to incorporate on-board bioluminescence (and fluorescence)
imaging (BLI) and tomography (BLT) to guide focal irradiation of small soft
tissue targets. Feasibility studies with an implanted bioluminescence sourcein an idealized mouse cadaver model show that an off-line BLT approach
could achieve center-of-mass localization of a BL target with an accuracy of
about 2 mm, suggesting a margin expansion of 4 mm or more would be required. However, studies with a phantom model show that an on-line BLT
complemented with CBCT derived priors would achieve localization accuracy
to within 1 mm, affording a resultant margin expansion of about 2 mm. The
on-board BLI/BLT capability greatly reduces the setup uncertainty associatedwith off-line animal transport and provides a powerful utility to study radiation
response in a living animal. Recognizing the important research utilities ofboth BLT and the SARRP, a dual-use model has been designed and underconstruction to allow each system to function independently, but also as anintegrated system via a novel docking approach. Results from our on-going
pre-clinical focal irradiation studies and advanced system developments will
be presented.
Conclusions: SARRP represents one of several pre-clinical radiation research systems with advanced imaging capabilities to allow the delivery ofconformal radiation to better model human treatment methods. It is becoming
clear that these systems can be used to address many important questions
about radiation treatment and response that could not be studied previously.
At the time of writing, about 10 such systems have been installed at various
institutions, and more will be installed in the near future. We await the exciting
findings from the new experiments that are on-going.
Supported in part by a grant from Xstrahl Ltd (previously Gulmay Medical)
which is commercializing the SARRP for the research community.

INTENSITY MODULATED CT
D. Jaffray
Abstract not received.

143 speaker
PHASE CONTRAST IMAGING: TOWARDS CLINICAL APPLICATION
A. Bravin1
1
E UROPEAN S YNCHROTRON R ADIATION FACILITY, Medical Physics,
Grenoble, France
Phase-contrast imaging (PCI) has emerged as a novel X-ray-based imaging
approach providing enhanced image contrast in biologic tissues and suggesting the potential to improve the diagnostic work-up. Unlike absorption-based
imaging, used in medical diagnostics, PCI uses the fact that X-rays are not
only absorbed but also refracted when passing through matter. These two
effects can be described in terms of a complex index of refraction for X-rays;
the real part corresponds to the refraction and the imaginary one to the absorption. For the energy range used in medical diagnostics and for the soft
tissue especially encountered in medicine, the real part is at least two ordersof magnitude larger than the imaginary one so that the phase contrast effectis much higher than the absorption contrast. Thus, PCI techniques may allow
for visualization of contrast in tissues in which conventional absorption-based
contrast is weak or absent without losing its excellent depiction of high X-ray
absorbing details.
Several techniques have been developed to visualize the phase contrast effects: free space propagation, analyser- based, interferometric- and gratingsbased.
Both the free space propagation and the analyser-based techniques havebeen successfully applied in comparative studies in excised mammographic
samples. Film screen-film and digital phase contrast mammograms havebeen correlated with histological information of the specimens, with the result that PCI was able to dramatically increase the visualization of tiny details.
In analyzer-based imaging high-contrast breast computed tomography at highspatial resolution and a clinically acceptable radiation dose has been demonstrated on full breasts. Pilot clinical trials using projection imaging and thefree propagation technique are being performed at the Elettra Synchrotron
Radiation facility in Trieste, Italy.
In addition to mammographic studies, non-invasive detection of cartilage abnormalities, especially in the initial stages of degenerative joint disease (osteoarthritis) or early in its progression, and also the possibility of non invasively evaluate the status of ingrowth of bone tissue into the implant surface
have also been shown by several authors. In other tomographic in-vitro studies it was possible to obtain an excellent depiction of the 3D architecture of
the cartilage in human patellae and to quantitatively analyse the chondrocyte
content in osteoarthritic vs. normal samples: the latter showed statisticallysignificant lower chondrocyte distribution homogeneity, lower height of tangential, transitional, and radial zones and a higher prevalence of supercial
cartilage damage. Finally, proof of principle of in-vivo studies in small animals on articular joints of guinea pigs, to observe objective early signs of osteoarthritis, have opened the way to more complex longitudinal studies which
could be used to verify the effect of anti-osteoarthritis therapies.
Several kind of biological samples, like animal and human brain, humanhands etc have been analysed in in-vitro laboratory experiments using thegrating interferometer technique. As an example, extraordinary results havebeen obtained in imaging formalin-fixed rat brain, where good contrast between the brain’s white and gray matter was achieved. Although such differentiation is usually hardly possible based on X-ray CT scans, this method
clearly resolved these small density differences in the brain tissue structure.
Phase contrast medical imaging is still in the developments phase, and ispresently mainly applied at large scale facilities, i.e. synchrotron radiation
sources, because these techniques require either quasi-monochromatic radiation, quasi parallel X-rays, small source sizes, naturally available at thosefacilities. When these conditions are not satisfied, depending on the case,either the image phase contrast registration is not possible or the signal appears extremely weak, or requires long acquisition times, incompatible withthe diagnostic practice. In this context, on-going developments towards small
source size and more powerful conventional X-ray sources are certainly extremely exciting. In addition, one of the most promising technologies for transporting phase contrast imaging into a clinical environment is represented by
the ’table-top’ synchrotrons under development around the world, based on
the so-called Inverse Compton scattering principle.
In this paper, the present status of the art of PCI and the potential clinicalapplications will be presented and discussed.

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S YMPOSIUM

Symposium
Safety in radiation therapy - Joint Symposium with
Physics
144 speaker
INTERNATIONAL INCIDENT REPORTING: LESSONS FROM ROSIS
J. Cunningham1
1
TCD D IVISION OF R ADIATION T HERAPY, Radiation Therapy, Dublin,
Ireland Republic of

Background and Purpose: Incident reporting is a recognised tool for learning from incidents. The Radiation Oncology Safety Information System (ROSIS) was established in 2001, to collate and share information on incidents
and near-incidents in radiotherapy, and to learn from these incidents in thecontext of departmental infrastructure and procedures.
Materials and Methods: The data was collected from online Department
Description and Incident Report Forms. 101 Departments and 1074 Incident
reports are evaluated.
Results: The ROSIS Departments represent about 150,000 patients, 343
megavoltage (MV) units, and 114 Brachytherapy units. A total of 1074 reports were analysed; 97.7% relate to external beam radiation treatment and
50% resulted in incorrect irradiation. Many incidents arise pre-treatment, but
are not detected until later in the treatment process. The most commonly reported detection methods were "found at time of patient treatment" and during"chart-check" (Table 1). From a hazard identification frequency analysis, themost common hazards were related to dose (32%), target volume (31%),
and accessories (20%). A classification system was developed with fourmain classes Event/Occurrence, Outcome, Causes/Contributing factors, andDetection. With the exception of the category "Treatment Preparation", theprocess classification showed good inter-rater reliability (Pearson Chi-Square
8.134, p=0.616). Most incidents originated in the pre-treatment stages of the
RO process (359 of 500 classified). The most commonly reported incorrect
parameters were the position of the isocentre within the patient, and the field
geometrical parameters. Datasets were defined for the classification, anddynamic web-forms were developed encompassing these datasets to enableclassification of information at source by the reporter.
Conclusion: The majority of ROSIS reports relate to external beam radiation
treatment; half of the events reported resulted in some treatment delivered incorrectly. Although the majority of incidents reported are of minor dosimetricconsequence, many did bypass defences indicating a need for further evaluation of the effectiveness of quality controls. Responding to the need for more
standardised data collection, a classification system has been devised andimplemented prospectively via department and incident forms. The incorporation of the classification into dynamic forms should facilitate the prospective
collection of the classification dataset, but should be evaluated for validity andreliability.

145 speaker
PREVENTING ACCIDENTAL EXPOSURES FROM NEW EXTERNAL
BEAM RADIATION THERAPY TECHNOLOGIES
O. Holmberg1
1

I NTERNATIONAL ATOMIC E NERGY AGENCY, Radiation Protection ofPatients Unit; Radiation Safety and Monitoring Section; NSRW, Vienna,
Austria
In order to prevent future accidents in radiotherapy, it is necessary to learn
from accidents that have occurred in the past. When aiming to learn fromthese past accidents, it is of value to analyse the specific case histories andfind the causes, contributing factors, actual circumstances of discovering theaccident as well as methods for future prevention. Lessons from accidental
exposures are therefore a crucial resource for revealing vulnerable aspectsof the practice of radiotherapy, and for providing guidance for prevention of
future occurrences.

M ONDAY, M AY 9, 2011
While new external beam radiation therapy technology brings improved radiotherapy, it might also bring an increase in complexity as well as new and
not foreseen error modes. Effective and timely sharing of information about
incidents and near misses involving the use of new radiation therapy technologies becomes a crucial aspect of safety in radiotherapy. In addition, it isof value to enable new users to share experiences in the safe implementationof new technology.
While these actions will help to increase safety for the radiotherapy patient,
they should be complemented by prospective safety analysis. This is especially important when it comes to new technology, where experiences might
not yet have been gained in relation to the new and different error modes.
ICRP recently published its Publication 112 "Preventing Accidental Exposures from New External Beam Radiation Therapy Technologies" wherethese points were made. In addition, a number of specific recommendations
were made in relation to e.g. training of staff, responsibilities of manufacturers and users, handling of images, uniformity and clarity in data transfer approaches, interdisciplinary communication, as well as the approach tosafety culture in radiotherapy. While lessons learned from incidents and accidents in conventional radiotherapy were found to be still valid, the increasingly
complex new technologies require an even more informed safety strategy.
Approaches and recommendations will be presented, together with actions
taken by the IAEA in this area.
146 speaker
THE ROLE OF EDUCATION AND TRAINING IN PROVIDING SAFERADIOTHERAPY
M. D. C. Lopes1
1

I NSTITUTO P ORTUGUÊS DE O NCOLOGIA DE C OIMBRA F RANCISCOG ENTIL , EPE, Medical Physics, Coimbra, Portugal

Modern radiotherapy is heavily dependent on humans interacting with complex technology where computer controlled processes demand high vigilance,awareness and personal commitment to treatment quality and patient safety.
Different professionals in several disciplines work together, each contributing to the entire process. They must perform highly sophisticated sub-tasks
where the potential for technical failure and/or human error is large. Theseduties demand the development of a safety culture that includes measures toencourage an alert and learning attitude and that discourages complacency
concerning safety.
Organizational and human factors, especially insufficient human resources,
excessive workloads, and inadequate skills, education and training have been
identified as major causes of adverse events in radiotherapy.
In the last few years three different approaches to safety in radiation therapy
have been identified. They are the prescriptive, reactive and proactive methods of risk assessment. Prescriptive methods are based on the verificationof institutional and individual compliance with regulatory requirements, codesof practice and international standards. Reactive methods are approaches
that use accident analysis, lessons learned and safety assessments from reported accidents. The need for previewing non reported accidents was oneof the motivations for the development of newer approaches to risk analysis
in radiation therapy that constitute the class of proactive methods. These
are based on a search for all potential failures and errors, estimating theirlikelihood and prioritizing the management and organizational measures toreduce the probability of events leading to higher risk.
In this presentation we will examine the three safety approaches in the context of the education and training initiatives at the European and international
levels towards providing safer radiotherapy.
Following the prescriptive approach recent efforts in core curriculum development for medical physicists will be presented. In Europe, the recast of theEuropean Basic Safety Standards Directive was the driving force for this update with appropriate recommendations on harmonizing education and training within the existing EU legislative network.
The reactive perspective concerning education and training will be illustrated
by the action plans and recommendations following the occurrence of several
safety-related incidents in USA. Also the French health authorities, subsequent to the accidents reported in 2006 and 2007, called for a plan to improvesafety and quality in radiation therapy that deserves reference.
Finally, the rational of proactive methods will be applied to the need for continuous professional development (CPD) for all individuals involved in the radiotherapy process.
Lifelong learning through CPD is particularly important in radiotherapy due
to the rapid and continuous technological developments that demand welltrained, motivated and technically educated personal. All professionals
should maintain their skills and competencies not just at an individual levelbut as a team. The periodic assessment of skills mix and staffing levels isparticularly important before the introduction of new treatment techniques orprocedures.
The detailed description of each operational procedure or work instruction
should state the qualifications required for each task, with the recognition thatin many cases the tasks require competency-based training in addition tominimum academic or professional qualifications. Training in how errors may
occur in radiotherapy and how they may be predicted and prevented shouldbe part of the construction of a safety culture. A multidisciplinary working
environment with clear communication is essential to providing safer radio-

M ONDAY, M AY 9, 2011
therapy. Such a culture, open and non-punitive, should be actively encouraged through regular multidisciplinary meetings to promote inter-professional
communication while respecting and understanding the different roles andresponsibilities of individuals. Communication among staff members is essential for all aspects of the radiotherapy process, since mistakes may bemade because of lack of adequate communication, incorrect information, or
poor understanding of correct information.
As a concluding remark it should be acknowledged that education and training is not the only contributing factor to improving safety in radiotherapy. Nevertheless, the different approaches to acquisition of knowledge, skills andcompetencies are certainly a fundamental pillar supporting patient safety.

P ROFFERED PAPER

S 55

Proffered paper
GEC Proffered Papers 3: Cervix Cancer
147 oral
MULTICENTRE STUDY OF MRI-GUIDED BRACHYTHERAPYTREATMENT PLANNING: COMPARISON AMONG TANDEM OVOIDAPPLICATOR USERS
C. Nomden1 , A. de Leeuw1 , E. Van Limbergen2 , M. De Brabandere2 , A.
Nulens2 , R. Nout3 , M. Laman3 , M. Ketelaars3 , B. Reniers4 , L. Lutgens4 , I.
M. Jürgenliemk-Schulz1
1
U NIVERSITY M EDICAL C ENTER U TRECHT, Radiation Oncology, Utrecht,
Netherlands
2
U NIVERSITY H OSPITAL G ASTHUISBERG, Radiation Oncology, Leuven,
Belgium
3
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Clinical Oncology,
Leiden, Netherlands
4
MAASTRO CLINIC, Radiation Oncology, Maastricht, Netherlands
Purpose: To compare different MRI-guided brachytherapy (BT) treatment
planning methods for cervical cancer in 4 centres that use the tandem-ovoid
applicator.
Materials: For this study we selected 4 patients from the Utrecht clinicaldatabase that are included in the EMBRACE study. High risk clinical target volumes (HR-CTV) and organs at risk (OAR) were delineated according
to GEC-ESTRO recommendations and applicator reconstructions were performed. Volumes of HR-CTV were 19.5, 31.9 33.8, and 68.0 cm3 . Three ofthe 4 patients were clinically treated with the intracavitary/interstitial (IC/IS)
approach, and one intracavitary alone.Four centres (2 using PDR and 2
HDR) with different historical BT background performed treatment planningon these data sets. Each centre created for each of the 4 patients the following plans: an institutional standard (STD) plan normalised to point A, an
optimised MRI-guided treatment plan without (OPT) and one with use of interstitial needles (OPTN). One centre had no experience with the IC/IS approach and therefore did not generate the OPTN treatment plans. The aim
for the D90 HR-CTV (dose given to 90% of the high risk volume) was 85Gy
EQD2 for all treatment plans. The dose constraints for the OAR’s (bladder,
rectum, sigmoid and bowel) were 90, 75, 75 and 75Gy EQD2, respectively.
All centres kept their institutional ’soft constraints’ for treatment planning.We
analysed and compared DVH-parameters, source loading patterns, dose distributions and ’soft constraints’.
Results: The D90 HR-CTV values derived from the STD plans were similar
while variations in OAR’s dose were noticed. Optimisation resulted in smaller
variations in the OAR doses while by adding interstitial needles the variation
increased. Optimised plans with needles showed in all cases higher D90
HR-CTV than without needles but the variation among the centres increased.
The source loading patterns (SLP) of the standard treatment plans varied
between the 4 centres. After optimisation the SLP were more comparable.
However, the dwell weights chosen for the source positions varied, resulting
in different contributions of the applicator parts to the dose distribution. Figure
1 shows an example of one of the patients. The ratio between the D2cc OAR
and the D90 HR-CTV, decreased from STD over OPT to OPTN. A lower ratio
represents the favourable situation of a lower dose to the OAR and a higher
dose to the HR-CTV.

Conclusions: MRI guided treatment planning results in more comparable
DVH parameters than standard planning. The relative contributions of thetandem, ovoids and needles were quite different between the centres. It isremarkable that although similar dose objectives were applied and obtainedfor D90 HR-CTV and D2cc OARs the dose and source time distributions arequite different. This study induced discussions on source loading patterns,
dose distributions and other soft constraints, which in the future may lead tomore comparable treatment approaches.

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to the D2cc (bladder, rectum).

LOCAL RECURRENCES IN CERVICAL CANCER PATIENTS IN THE
SETTING OF MRI-GUIDED BRACHYTHERAPY: A COMPARISON
OF SPATIAL DOSE DISTRIBUTION WITHIN A MATCHED-PAIRANALYSIS
M. Schmid1 , C. Kirisits1 , J. C. A. Dimopoulos2 , N. Nesvacil1 , R. Pötter1
1
M EDICAL U NIVERSITY V IENNA , AKH, Vienna, Austria
2
M ETROPOLITAN H OSPITAL, Athens, Greece
Purpose: To describe different patterns of local recurrence (LR) in patientswith cervical cancer treated in definitive intent with EBRT +/- chemotherapy and MRI-guided brachytherapy and to compare dose volume histogram(DVH) parameters and dose points between patients with LR and patients incontinuous complete local remission (CCLR).
Materials: From 1998 to 2010 24 LRs were documented. For the statistical analysis all patients with LR were randomly matched to patients in our
database in CCLR (n=241) according to the following criteria: FIGO stage,
histology, lymph node status, tumor size, chemotherapy.HR CTV was contoured for all patients and DVH parameters (D90, D100) were assessed. In order to report the minimum dose at the region where the recurrence occurred,
the HR CTV was divided in 4 quadrants on transversal planes. The minimum dose at the HR CTV contour was measured (within the corresponding
quadrant closest to the LR) in the treatment planning system. A mean minimum point dose (MPD) was calculated by averaging these measurements
on 4 consecutive slices at the level of the recurrence for each brachytherapy fraction. EQD2 doses were calculated by summation of all 4 fractions
and external beam therapy.For each matched patient in the control group themeasurements were performed on the same quadrant and at the same level.
Results: Sufficient image data was available for 21 LRs. 8 central failuresand 13 non-central failures were observed. The mean D90 and D100 for
HR CTV were 78Gy and 61Gy for patients with LR and 93Gy and 70Gy forpatients in CCLR, respectively (p<0.01). The MPD was 72Gy for patients in
the LR arm and 100Gy for patients in the CCLR arm (p<0.01). In the LR arm
8 patients had a D90 for HR CTV ≥87Gy, however in 16 patients the MPD
was <78Gy.
Conclusions: This study demonstrated significant differences in local outcome according to the delivered dose. In 76% of the LRs systematic underdosage with less than 78Gy was found at HR CTV contour. While theminimum dose in any part of the target volume contributes to the D100, theMPD seems to be a clinically more relevant dose parameter. In addition to
DVH parameters, inspection of the spatial dose distribution remains a key
point in dose prescription.
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FEASIBILITY OF APPLYING ONE TREATMENT PLAN FOR SUCCEEDING FRACTIONS IN IMAGE GUIDED BRACHYTHERAPY IN
CERVIX CANCER
S. M. I. Mohamed1 2 , S. K. Nielsen3 , L. U. Fokdal1 , J. C. Lindegaard1 , K.
Tanderup1
1
A ARHUS U NIVERSITY H OSPITAL, Oncology, Aarhus C, Denmark
2
N ATIONAL C ANCER I NSTITUTE , C AIRO U NIVERSITY, Radiation Oncology
and Nuclear Medicine, Cairo, Egypt
3
A ARHUS U NIVERSITY H OSPITAL, Medical Physics, Aarhus C, Denmark
Purpose: Cervical cancer is highly prevalent in developing nations. Optimal image guidance approaches requires good resources as it implies multiple imaging and individualised planning for each brachytherapy (BT) fraction.
This study explores the feasibility of limiting dose optimisation to the first fraction (BT1) and applying the same plan for the second fraction (BT2).
Materials: 75 pts with cervical cancer were reviewed. EBRT of 45-50 Gy/25
fractions was administered to the pelvis. PDR-BT was initiated after about
4 weeks of EBRT with an intracavitary (IC) tandem-ring applicator alone
or combined with interstitial needles (IC/IS). The target volumes and OARs
were delineated according to GEC ESTRO guidelines. Optimisation was performed according to treatment planning aims: >85 Gy to HR-CTV, <90 Gy to
bladder, and <75 Gy to rectum and sigmoid in terms of equivalent dose in 2
Gy fractions. For patients with the same applicator geometry the optimised
BT1 plan was copied to BT2 with no further optimisation (single plan scenario). DVH parameters for full optimisation were compared to those of thesingle plan scenario.
Results: 31/43 IC pts had the same applicator geometry in both fractions.
With a mean HR CTV volume of 24.4cc and 23.6cc for BT1 and BT2, respectively. Only a minority of IC/IS pts (4/32 pts) had comparable applicatorgeometry for both fractions, and application of a single plan for two fractions
was not generally feasible in IC/IS patients. For the 31 IC pts with the same
applicator geometry, mean DVH parameters were comparable between full
optimisation and single plan scenarios (table). Only D100 and V100 for the
HR CTV were significantly different. The standard deviation of the difference(table) was up to 3 Gy and indicated individual benefit from optimization. 2/31
pts would receive HR CTV dose marginally less than 85 Gy (84 Gy) for the
single plan scenario. OAR planning aims were fulfilled for all patients with asingle plan, although 5/31 pts would receive between 3 Gy and 10 Gy extra

Conclusions: For IC BT, comparable mean DVH parameters resulted when
applying a single plan, although individual benefit of full optimisation was stillobserved for a fraction of pts. These results are most likely dependent on
the fact that BT is delivered in the late phase of the EBRT schedule, so thatno tumour shrinkage is seen between BT1 and BT2. Individual optimisationfor each BT fraction is recommended for high precision brachytherapy wheninterstitial needles are used.
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EFFECTS OF FULL VS EMPTY BLADDER ON TOTAL EQUIVALENTDOSE TO ORGANS AT RISK IN 3D IMAGE-BASED PLANNING
OF HIGH-DOSE-RATE INTRACAVITARY BRACHYTHERAPY FORCERVICAL CANCER
R. Kim1 , A. Dragovic2 , S. Shen2
1
U NIVERSITY OF A LABAMA AT B IRMINGHAM, Birmingham, USA
2
U NIVERSITY OF A LABAMA AT B IRMINGHAM, Department of Radiation
Oncology, Birmingham, USA
Purpose: Our previous study has shown that an increase in bladder volume
during high-dose-rate (HDR) intracavitary brachytherapy (ICBT) results in asignificant reduction in bowel D2cc values at the expense of an increase inbladder D2cc values.This information may in turn be used to modify treatment planning strategies to reduce toxicity from excess dose to organs at risk
(OARs). We seek to assess one such modification by examining the effectof a full or empty bladder on the total equivalent dose in 2 Gy fractions (theEQD2) received by OARs after 45 Gy of external beam radiotherapy (EBRT)and ICBT.
Materials: Thirteen consecutive patients with cervical cancer were treatedwith HDR ICBT using tandem and ovoid applicator after completion of wholepelvic EBRT. Patients underwent CT simulation with Foley catheter in placewith 180cc of a 5% Omnipaque solution instilled into the bladder to aid in contouring (defined as full bladder). A second simulation scan was performed after draining the bladder (defined as empty bladder). The full or empty bladderscan was chosen for treatment based on the proximity of small bowel to thetandem. For the purpose of this study, treatment planning was then performed
without optimization for OAR to deliver either 8 Gy x 3 fractions or 7 Gy x 4
fractions to Point A. External contours for rectum, bladder, sigmoid, and small
bowel were retrospectively drawn on both full and empty bladder scans anddose volume histograms (DVHs) were used to determine the D2cc for each
OAR over the course of ICBT. Using the linear quadratic model equations,
the EQD2 for each OAR was calculated from the D2cc values from the ICBT
componenet and added to EQD2 from the EBRT component to obtain the total equivalent dose to each OAR. Our goals for OARs were: 90 GyEQD2 forbladder, 75 GyEQD2 for both rectum and sigmoid, and 60 GyEQD2 for small
bowel (α/β = 3 Gy).
Results: For patients with a full bladder, the mean bladder EQD2 increased
from 82.3 to 97.1 GyEQD2 (18% increase, p=0.017) compared with empty
bladder. Conversely, the mean small bowel EQD2 decreased from 76.2
to 63.8 GyEQD2 (16% decrease, p<0.001), and mean sigmoid EQD2 decreased from 78.8 to 73.7 GyEQD2 (6% decrease, p=0.067). Mean rectal
EQD2 values remained stable at 69.7 and 69.4 GyEQD2 for full and empty
bladder, respectively (<1% change, p=0.82). A varying magnitude of small
bowel sparing was observed, depending on the position and size of theuterus, and location of small bowel. With full bladder, our goals for EQD2
were met more frequently for sigmoid (7/13 vs. 4/13) and small bowel (6/13
vs. 1/13); while bladder EQD2 goal were met more frequently if the bladder was empty (8/13 vs. 6/13). No differences were seen in meeting goals
for rectal EQD2 (9/13 vs. 9/13). Movement of the sigmoid colon was seen
frequently during full and empty bladder.
Conclusions: Our goals for OARs are met more frequently with full bladderby pushing small bowel away from intrauterine sources. However, the decision to use a full or empty bladder for ICBT must be individualized due toanatomical factors.

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ANALYSIS OF SPATIAL AGREEMENT BETWEEN CT (+PREBTMRI) AND MRI BASED HRCTV DELINEATION IN CERVIX CANCER
BRACHYTHERAPY
M. Federico1 , I. Fotina1 , N. Hegazy12 , C. Kirisits1 , A. Sturdza1 , D. Georg1 ,R. Pötter1
1
M EDICAL U NIVERSITY V IENNA , AKH, Department of Radiotherapy,
Vienna, Austria
2
M EDICAL U NIVERSITY OF A LEXANDRIA, Department of Clinical Oncology,
Alexandria, Egypt

DOSIMETRIC AND CLINICAL RESULTS OF A FRENCH PROSPECTIVE STUDY OF 3D BRACHYTHERAPY FOR CERVIX CARCINOMA
C. Charra-Brunaud1 , M. Levitchi2 , M. Delannes3 , C. Haie-Meder4 , P.
Quetin5 , C. Kerr6 , L. Thomas7 , I. Barillot8 , D. Peiffert1
1
CRAN - C ENTRE A. VAUTRIN, Radiation Oncology, Vandoeuvre-lès-Nancy
Cedex, France
2
C ENTRE A LEXIS VAUTRIN, Radiation Oncology, Nancy, France
3
I NSTITUT C LAUDIUS R EGAUD, Radiation Oncology, Toulouse, France
4
I NSTITUT G USTAVE R OUSSY, Brachytherapy, Villejuif, France
5
C ENTRE H OSPITALIER R EGIONAL, Radiotherapy
6
CRLC VAL D ’AURELLE /PAUL L AMARQUE, Radiation Oncology, Montpellier
Cedex 5, France
7
I NSTITUT B ERGONIÉ, Radiation Oncology, Bordeaux, France8
H ÔPITAL B RETONNEAU, Radiation Oncology, Tours, France

Purpose: MRI-based target delineation is considered as "high standard approach" in brachytherapy (BT) planning for cervix cancer. If availability of MRI
for planning and contouring is limited, there is a possibility to delineate on
CT referring to pre-BT MR. The aim of this study was to evaluate the agreement between contouring of HRCTV on CT using pre-BT MR information and
MRI-based delineation in cervical patients with different stage disease. The
analysis was performed with focus on spatial agreement between CT and MR
contours.
Materials: MRI and CT images with applicator in place were obtained from27 cervix patients (6 patients with stage IB1 or IB2, 13 patients with stage
II, and 8 with stage III or IVA) who received definitive treatment for cervicalcancer. HRCTV was retrospectively contoured on CT, referring to diagnostic pre-BT MRI (HRCTV-CTpreBTMRI), and compared to the planning MRI(HRCTV-MRI) contour. The images were fused and volumes were evaluated with ARTiView (Aquilab, France) software. Volume ratio, volume overlap (VO), conformity index (CI=ratio of overlap volume to the encompassing
volume), CT additional volume (CTadd) and MRI additional volume (MRadd)
were evaluated for the spatial agreement analysis of the contours (see Fig 1).
As MRadd volume is influenced by applicator delineation uncertainty on MR
images, in the fused images the applicator intersection with MRadd volume
was subtracted from the contours as shown in the Fig.1.

Fig. 1 Schematic representation of the volumes used for the evaluation.
Results: Mean HRCTV-CTpreBTMRI to HRCTV-MRI volume ratio was 1.04
for Stage IB1-IB2 patients, 1.08 and 1.17 for Stage II and III-IVA, respectively.
Mean CI was 0.60 for stage IB1-IB2, 0.49 stage II, 0.58 for stage III-IVA.. VO
values of HRCTV-CTpreBTMRI with HRCTV-MRI were 75,7%, 67,5% and78,5% for Stage IB1-IB2, II and III-IVA, respectively. Largest median CTadd
volume was reported for stage III-IVA cases with 12.5 ccm, followed by stage
II with 10.4 ccm and stage I with 6.1 ccm. Median MRadd volume was foundto be smaller for Stage IB1-IB2 cases (5.0 ccm) and Stage II (4.9 ccm) compared to Stage III-IVA (6.9 ccm).
Conclusions: CT-based contouring of HRCTV with information from preBT MRI results in overall volumes comparable with MRI-based contouring.
Spatial displacement analysis shows, however, that HRCTV-CTpreBTMRI includes only 70 to 80% of HRCTV-MR. The best agreement (highest CI) was
achieved for Stage I cases. Stage I cases have the smallest CT additional
volume and smallest MR additional volume. Presence of MRadd volume, indicating geographical miss of CT-based contouring, is more pronounced forStage IVA and located in the areas of gross tumor invasion, not visible on CT
images. CTadd volume for Stage IVA patients results in inclusion of > 10 ccm
additional volume.

Purpose: To describe dosimetric and clinical data of cervix cancer patientstreated with 3D pulse dose rate brachytherapy (BT).
Materials: A total of 352 patients received 3D BT with or without externalbeam radiotherapy (EBRT) and/or surgery as part of a prospective study
on cervix BT. Three sub groups of patients have been defined according to
the treatment realized: group 1, brachytherapy followed by surgery; group2, EBRT followed by BT then by surgery; group 3, EBRT followed by BT.
EBRT median dose was 45 Gy/25 fractions, associated with chemotherapy
in more than 80% of the cases (mostly weekly cisplatyl).The DVH parameters for CTVs and organs at risk (OARs) were computed as recommended
by GYN GEC ESTRO, as well as ICRU point doses (DICRU). Total doses
were converted to biological equivalent doses by applying the linear-quadraticmodel (α/β = 3 Gy for OARS, 10 for CTVs). Side effects were prospectively
assessed using the CTCAEv3.0.
Results: : The median follow-up was 23.4 months. Dosimetric and clinicalresults are presented in the following table:

Among operated patients, 63% were in complete pathological remission.
Complete remission was correlated with local control; no dosimetric parameter was correlated with complete remission. D90 for HR CTV and IR CTV
were not correlated with local control, whereas IR CTV V60 was correlatedwith local control for groups 2 and 3. among group 3 patients, TRAK anddose to point A were also correlated with local control. Concerning toxicities,
a D2cc rectal dose over 68.3 Gy3 was a significant predictive value for Grade
2-4 gastrointestinal toxicity (HR 3.5); a D2cc bladder dose over 91 Gy3 wasalso predictive for grade 2-4 urinary toxicity (HR 2.6). Smoking had a significant predictive value on urinary Grade 2-4 toxicity with hazard ratio of 2.6.
Conclusions: 3D dosimetry is feasible for cervix brachytherapy and provides
high local control with an acceptable rate of severe toxicity. Cut offs levels
for digestive and urinary toxicity were close to GYN GEC ESTRO recommendations in our study. Increase of the dose is possible as maximal doses to
OARS were not always met, giving room for a further improvement of local
control.

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A 3D PROBABILITY MAP OF THE HR-CTV OF CERVICAL TUMOURSAT TIME OF BRACHYTHERAPY WITH A TANDEM AND OVOIDAPPLICATOR
R. van Leeuwen1 , C. Nomden1 , A. de Leeuw1 , I. M. Jürgenliemk-Schulz1
1
U NIVERSITY M EDICAL C ENTER U TRECHT, Department of Radiotherapy,
Utrecht, Netherlands
Purpose: High-risk clinical target volumes (HR-CTV) of cervical tumours at
the time of brachytherapy (BT) show large variation between patients in sizeand extent. The aim of this study was to map the 3D voxel-based probability
for the HR-CTV around a tandem and ovoid (T/O) applicator, based on delineations of 52 patients. We used this probability map to evaluate the potentialof standard and optimized treatment plans with respect to HR-CTV coverage.
Organs-at-risk (OAR) were not taken into account.
Materials: Delineations of the HR-CTV were made according to our clinicalprotocol, using three T2-weighted (4.5 mm slices) Turbo Spin Echo scans,acquired at the time of the first BT treatment. Nucletron Oncentra GYN software (OG) was used to reconstruct the position of the applicator. Based on
the reconstruction data, individual delineations were backprojected onto a reference applicator. The number of HR-CTV delineations encompassing eachvoxel was determined to create a 3D probability map (value 52 = 100%; 0 =0% chance of HR-CTV). From this map, we derived contours of equal probability, or isosurfaces. The 50%, 30%, 20% and 10% isosurfaces were used asmodels for HR-CTVs of different sizes (lower % = larger HR-CTV). Using OG,
for each HR-CTV model, two clinically-used standard loading patterns werecompared in terms of 3D dose distribution and D90 values. Furthermore, we
evaluated the effect of optimization on these parameters for the 20% and 10%
models, in the latter case making use of additional interstitial needles.
Results: At the level of points A, the width of the 50% HR-CTV model was 33
mm in the lateral direction, and 29 mm in the ventro-dorsal direction. The 10%
model measured 60 mm laterally, and 50 mm along the ventro-dorsal axis,
with a preference for the dorsal direction. Measured along the intrauterine
catheter, the 50% model extended 36 mm and the 10% model extended 56
mm above the ovoids.No large differences in D90 values were found between
the two standard loading patterns for the model HR-CTVs, although the 3D
dose distributions varied substantially. For the 30% and 50% models, standard loading patterns were sufficient to achieve the prescription dose (PD).
For the 20% model, the D90 was just below the PD, making small optimizations necessary. For the 10% model, a D90 of 77% of the PD was reached.
After optimization, including additional dorso-lateral interstitial needles, thePD was reached, while complying with our clinical requirements in terms ofhigh-dose regions and conformity.

Conclusions: We have created and characterised a 3D probability map for
the HR-CTV of cervical tumours, providing insight into the extent of the HRCTV in a cohort of 52 patients. Although OAR have not yet been taken into
account, we have shown that an important part of cervical tumours profit
from 3D MRI-guided optimization and the additional placement of interstitial
needles. Our probability map can be used to improve the design of the T/Oapplicator.

GEC Proffered Papers 4: Brachytherapy Physics
154 oral
CHALLENGES AND REQUIREMENTS FOR THE INTRODUCTION
OF MODEL-BASED DOSE CALCULATION ALGORITHMS IN
BRACHYTHERAPY: A STATUS UPDATE FROM AAPM TASK-GROUP
186
L. Beaulieu1 , Carlsson Tedgren2 , J. F. Carrier3 , S. Davis4 , F. Mourtada5 ,M. Rivard6 , R. Thomson7 , F. Verhaegen8 , T. Wareing9 , J. Williamson10
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Quebec, Canada
2
L INKÖPING U NIVERSITY, Linköping, Sweden
3
CHUM - C AMPUS N OTRE -DAME, Montréal, Canada
4
M C G ILL U NIVERSITY H EALTH C ENTER, Montreal, Canada
5
U.T. M.D. A NDERSON C ANCER C ENTER, Houston, TX, USA
6
TUFTS-N EW E NGLAND M EDICAL C ENTER, Boston MA, USA
7
C ARLETON U NIVERSITY, Ottawa, Canada
8
M AASTRICHT R ADIATION T HERAPY AND O NCOLOGY (MAASTRO) CLINIC,
Maastricht, Netherlands
9
T RANSPIRE I NC, Gig Harbor, WA, USA
10
V IRGINIA C OMMONWEALTH U NIVERSITY, Richmond, VA, USA
Purpose: Factors influencing brachytherapy (BT) dose calculations are highly
dependent on BT source energy and can be traced to scatter conditions andthe variation of photoelectric effect cross-sections relative to water with energy. In contrast to external beam radiotherapy (EBRT), the BT community
has not yet adopted heterogeneity-correction algorithms. In 2009, an AAPM
task group (TG-186) was formed to provide guidelines and practice standards for early adopters of model-based dose calculation algorithms (MBDCA). These include superposition/convolution, Monte Carlo and deterministic transport-equation solvers.
Materials: MBDCA pose three major issues that are not addressed by current guidance documents: 1) MBDCA doses are highly sensitive to choice ofdose specification medium, resulting in energy-dependent dose differences
between computing dose to water in homogeneous water geometry (Dw,w,closest to TG-43), dose to the local medium in the inhomogeneous geometry(Dm,m), and the intermediate scenario Dw,m. 2) MBDCA doses are highly
sensitive to voxel-by-voxel cross section assignments. Neither conventional
single-energy CT nor ICRU/ICRP tissue composition recipes are accurate
guides for the task. 3) With MBDCA each patient is unique and reference
data for all possible source-applicator-site combinations are impractical; a
new commissioning process is required.
Results: Radiation transport should be performed in the inhomogeneous geometry. However, the medium of choice for dose scoring remains an open
question. The difference between Dw,m and Dm,m can vary by up to a factor of 7. Dm,m is a natural quantity of any MBDCA while conversion into
Dw,m, the default in EBRT, requires specific guidelines.. For low-energy BT,
both cases differ significantly from the TG-43 formalism. For 192Ir, this isnegligible.Assignments of voxel-by-voxel cross section represent a particularchallenge. Density information should be extracted from CT imaging. This is
however insufficient and a recommendation is set forth to use a limited number of standardized materials to maintain uniformity across institutions. Sensitivity analysis shows the proposed materials offer increased accuracy over
TG-43.MBDCA commissioning will share commonalities with current TG-43based systems, but in addition there will be algorithm-specific tasks. Conditions similar to clinical BT practice for dosimetry parameter comparisons must
be replicated. For validation of heterogeneity and scatter conditions, MBDCA
should mimic the 3D dose distributions from reference virtual geometries. A
clinical flowchart has been developed
Conclusions: TG-186 identified recommendations and areas of research. At
this time, a single commercial MBDCA is available that has a limited range
of applicability. However, this offers an opportunity to establish uniform recommendations. This effort is critical to ensure that moving beyond TG-43 will
not be done at the expense of worldwide uniformity.
155 oral
ON THE POTENTIAL OF DUAL ENERGY CT TISSUE SEGMENTATION IN LOW ENERGY BRACHYTHERAPY DOSE CALCULATIONS
G. Landry1 , B. Reniers1 , P. Granton1 , F. Verhaegen1
1

D EPARTMENT OF R ADIATION O NCOLOGY (MAASTRO), GROW, U NIVER -SITY H OSPITAL M AASTRICHT , Maastricht, Netherlands

Purpose: The current low dose rate (LDR) brachytherapy dosimetry protocol
for low energy photons, AAPM TG43, ignores the effects of tissue composition. Given the photoelectric effect’s dominance at the low photon energies
in use, the dosimetry is dependent on the elemental composition of tissues.
AAPM TG186 was mandated to investigate model based dose calculation algorithms (MBDCA) such as Monte Carlo (MC) simulations as an alternative
to the TG43 approach. In MBDCA dose calculations, tissue densities are cur-

M ONDAY, M AY 9, 2011
rently extracted from CT data and published elemental compositions (Zeff)are either assigned to density intervals or organ contours. Such compositions are generally obtained from population averaged data sets and have
uncertainties. It has been shown that such uncertainties can have significant
impact on LDR MBDCA dosimetry accuracy. Furthermore CT is unable todifferentiate between most soft tissues since their Hounsfield Units (HU) areclustered in the [100,100] range. Dual energy CT (DECT) has the potential toprovide the effective atomic number Zeff of tissues in addition to their massdensity, possibly improving tissue segmentation. The goal of this study is toassess with a simulation study the dose calculation accuracy improvement
provided by MBDCA dose calculations performed with DECT based tissue
segmentation compared to single energy CT (SECT).
Materials: Virtual CT images have been generated using ImaSim, a CT simulation software based on the x-ray spectrum generator SpekCalc and ray
tracing. The attenuation coefficients of 17 human tissues and 15 RMI tissue substitutes were entered in ImaSim along with the energy response of a
Gd2O2S CT detector. HU measured on a Picker PQ5000 CT scanner at 120
kVp for the RMI tissue substitutes agreed with those from the simulated phantom in ImaSim. The average absolute difference was 20 HU. From images ofa virtual phantom containing human tissues obtained at 80 kVp and 140 kVp,electron density and effective atomic number were extracted. MC dose calculations were performed for 72 103 Pd seeds inserted in the phantom for threecases: (I) tissue segmentation based on the electron density obtained from
HU units from SECT at 120 kVp, (II) the same for the electron density andatomic number images from DECT and (III) the exact known compositions(reference case).
Results: The accuracy of the rhoZ algorithm is presented in Figure 1a. Figure 1b shows that MC dose calculations based on (I) have errors up to 20%
compared to the reference case while those based on (II, Figure 1c) show
minimal errors except for bone, whose electron density is very different fromits mass density. Some errors caused by volume averaging are also visible inboth cases.

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MONTE CARLO DOSIMETRY OF HIGH DOSE RATE GYNECOLOGICINTERSTITIAL BRACHYTHERAPY
M. Desbiens1 , M. D’Amours1 , H. Afsharpour1 , I. Thibault1 , L. Beaulieu1
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Radiation Oncology, Quebec, Canada
Purpose: High dose rate interstitial brachytherapy (HDR-ISBT) using Ir-192
remote afterloading can be successfully used in the management of gynecologic malignancies for patients unsuitable for intracavitary brachytherapy or
suffering from local recurrence. Dosimetry is made through the applicationof TG-43 formalism and optimized using inverse planning simulated annealing algorithm. The purpose of this study is to assess dosimetric effects ofthe presence of the applicator, air pockets in clinical target volume (CTV) andOARs along with tissue heterogeneities using the Monte Carlo (MC) method.
Materials: The CT based dosimetry has been achieved with the Geant4 MC
toolkit version 9.2. DICOM-RT files of 38 patients were exported from their
original treatment planning system (TPS) and imported into our own simulation platform. CT images were read and Hounsfield numbers converted
to densities by the CT calibration curve to build a virtual geometry of eachpatient. Using density threshold and contours information, the phantom wassegmented and tissues composition assigned to materials in accordance withICRU report 46 and NIST. Seed dwell times and seed positions were thenused to launch 4x10E9 photons. According to the clinical information, thephase space file of one of the two Ir-192 sources of interest microSelectronHDR classic or v2 (Nucletron, Veenendaal, The Netherlands) were used toaccelerate computation time. Each photon was tracked along his path anddose was scored assuming the kerma approximation. These dose distributions were compared to those obtained by conventional TG-43 based algorithm.
Results: Effects on the DVHs of tissue heterogeneities and the applicators
vary from patient-to-patient. It is seen that the CTV D90 can be overestimated by as much as 8 % of the prescription dose. For some patients, V100
and V150 calculated by MC simulations are reduced, as seen in the figure
for a prescription dose of 500 cGy, by 4 % and 10 % respectively. Dosimetric indices of the rectum are found to be lower by approximately 3 % for
most cases. Differences for urethra and bladder are usually below 1 %. CTV
indices are strongly affected by exclusion of the applicator volume and air
pockets from the CTV while the observed differences in OARs dose indices
are driven by heterogeneities.

Conclusions: Taking account of heterogeneities has relatively small effects
on dose distributions. However, the exclusion of air pockets and applicator
volumes from the CTV are important, which is common to both MC and TG43 dose distributions; it could be easily implemented and automated in TPS
without impacting computation times. Overall improvement in accuracy ofthe dose-volume parameters may be particularly valuable in assessing dosevolume-toxicity association.
Conclusions: DECT simulations show promise of marked improvement for
tissue segmentation in brachytherapy applications where dose calculation errors from miss-assignments may be large.

157 oral
4D U/S-BASED PROSTATE HDR BRACHYTHERAPY TREATMENTPLANNING: ANALYSIS OF INFLUENCE OF PATIENT MOVEMENT
AND ANATOMY ALTERATION ON THE PLAN QUALITY AND TREATMENT DELIVERY
N. Milickovic1 , P. Mavroidis2 , I. Nikolova1 , Z. Katsilieri1 , V. Kefala1 , N.
Zamboglou3 , D. Baltas14
1
K LINIKUM O FFENBACH G MB H, Department of Medical Physics Engineering, Offenbach am Main, Germany
2
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Department ofMedical Radiation Physics, Stockholm, Sweden
3
K LINIKUM O FFENBACH G MB H, Offenbach am Main, Germany
4
U NIVERSITY OF ATHENS, Nuclear and Particle Physics Section, Physics
Department, Athens, Greece

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Purpose: Modern HDR brachytherapy treatment for prostate cancer basedon the 3D ultrasound (U/S) plays increasingly important role. The purpose ofthis study is to investigate possible patient movement and anatomy alteration
between the clinical image set acquisition, made after the needle implantation, and the patient irradiation, and their influence on the quality of treatment.
Materials: We used 3D US image sets and treatment plans of 25 patientsobtained right after the needle implantation (clinical plan is based on this
3D image set) and before and after the treatment delivery. The change of
Dose-Volume-Histograms (DVHs) for prostate, urethra, rectum and bladder
was calculated for the different dose distributions. Furthermore, the conformity indices COIN were determined to account for the quality of the implant
based on the dose distribution of prostate, OARs and needles’ displacement.
In the figure shown below, COIN values for the reference dose (100%) including OARs are illustrated for the three groups of treatment plans. The response
probabilities of the prostate and OARs were calculated for each patient andtreatment plans together with the complication-free tumor control probability(P+) and biologically effective uniform dose.
Results: We notice the slight decrease of treatment quality with increase oftime between the clinical image set acquisition and the patient irradiation. We
show that in the case that there is patient body movement/anatomy alteration,
this results in modification of the DVHs, hence the plan quality (see figure
below). Still, since we use each implant for one only fraction, all the plans
based on pre and post irradiation imaging are still fulfilling our dosimetricprotocol. The observed average displacement of needles (1mm) and prostate(0.57mm) is quite small as compared with the average displacement noted
in several other reports in the literature and does not cause unacceptable
treatment plans. The change in the expected response rates among the threedifferent sets of treatment plans ranges between 0.5-1.5% for prostate, 0.12.3% for urethra while for bladder and rectum they remain unchanged. The
average P+ index shows a small variation between -1.2-0.4%.

M ONDAY, M AY 9, 2011(ρ) and radius (r) (see figure). The library templates in the GYN software
were optimised to minimise the systematic difference between the planned
and measured dwell positions and orientations. An Excel spreadsheet was
created to assess the effect that source orientation would have on the accuracy of dose calculation to a circle of points 25mm from the ring centre,
in the plane of the ring. The most posterior point on the circle (Rplane) approximates the location of the ICRU rectal point. These calculations were
performed for the 26mm diameter ring geometry.

Conclusions: The measured mean shift of anatomy and needles (beams)
is as low as 1.0mm that is lower by an order of magnitude to values known
from external beam irradiation. For high modulated plans as those in HDR
Brachytherapy such small shifts result in dosimetric changes which are in
general lower than 5%. The results of the expected treatment outcome support this observation. Our results demonstrate that quality assurance procedures have to be clinically implemented to guarantee anatomy and implantstability of the demonstrated order of 1mm. This can only be realized without
any manipulation of the implant and anatomy as it is the case when removing
the U/S-probe before treatment delivery.

Results: Measurements showed that in the ring applicator the distance between adjacent dwell positions was not a constant 2.5mm (range of 1.7 to
3.3mm) and that the source was oriented at an angle of 18±5 (1 s.d) to theapplicator lumen axis. Due to template format limitations, small systematicdifferences remained following optimisation (residual positional differenceswere less than ±1mm for sources in the ring plane, source orientation was
accounted for in dwell positions 1-20). A QA system was established to checkthe validity of the major changes made to the applicator templates. Whenplanning with a standard Vienna loading using a template where there is no
systematic positional error, but the sources are aligned with the applicator lumen axis, the dose at Rplane is underestimated by approximately 3%. The
under or over estimation of dose varies radially and is of a similar magnitude.
Conclusions: The non-uniformity of dwell position spacing and the deviationof the source orientation from the applicator lumen suggest that both factors
should be incorporated in library template design. The removal of systematic
errors in the geometry of the library template is only possible if the templatesources can be spaced by more than 2.5mm. For this reason, we suggestthat in future, library templates should be in a format which stores the positionand orientation of dwell positions, rather than just a list of catheter describing
points.

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159 oral

SYSTEMATIC ERRORS IN SOURCE POSITION AND ORIENTATIONIN RING APPLICATORS. DO THEY MATTER?
J. Lee1 , J. Thornton1 , C. Lee1
1C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics Department, Bebington, United Kingdom

COMPENSATOR-BASED INTENSITY MODULATED BRACHYTHERAPY
R. Flynn1 , Y. Kim1

Purpose: Our centre commissioned the Vienna Ring CT-MR Applicators andthe Oncentra GYN planning software. The planning software utilises editablelibrary applicator templates instead of manual catheter reconstruction. As
a result, systematic differences between the library template dwell positions
and the real dwell positions could introduce errors in the dose calculation. We
present our methods and findings when trying to minimise these errors.
Materials: Source positions (defined in a polar coordinate system by theangle θ ) in the ring applicator were imaged using a CR plate in a speciallydesigned jig. Fluoroscopy imaging of a check cable in the ring applicator wasused to measure source orientation with respect to the applicator lumen axis

1

U NIVERSITY OF I OWA H OSPITALS AND C LINICS, Radiation Oncology, Iowa
City, USA
Purpose: To demonstrate the feasibility of compensator-based intensity
modulated brachytherapy (CIMBT), which delivers conformal dose distributions to non-radially symmetric targets such as MRI-delineated cervical cancer tumors or non-spherical breast lumpectomy cavities with an electronicbrachytherapy (eBT) source. With CIMBT the eBT catheter is wrapped witha patient-specific compensator with spatially-varying thicknesses of an attenuator such as tungsten or lead, enabling IMBT delivery with no additional
moving parts. eBT x-rays are sufficiently low-energy (<50 keV) that compensators can be thin enough (<100 microns) to fit between the catheter andapplicator.

M ONDAY, M AY 9, 2011Materials: A 3-D CIMBT treatment planning system prototype was implemented with the MATLAB software, which simultaneously optimizes the compensator thickness distribution and the source dwell times at multiple positions. The dose calculation currently ignores scatter and uses a 50 keV Xoft
AxxentTM eBT spectrum. Oblique incidence of x-rays on the compensator isaccounted for. Conventional eBT and CIMBT treatment plans were generated
for an ellipsoidal tumor with a length of 10 cm, a width of 6 cm, and a heightof 4 cm. The compensator ran the full length of the tumor, and twenty-one
uniformly-spaced dwell positions were used.
Results: The cutaway in the Figure shows that the dose homogeneity on
the target surface for (a) conventional eBT is inferior to that of (b) CIMBT.
CIMBT reduced the difference between the minimum doses received by thehottest 10% and 90% of the tumor surface from 60% to 25% of the surfaceprescription dose, improving tumor coverage and reducing dose outside thetumor volume. The total mAs required to deliver CIMBT was twice that ofconventional eBT. No benefit was found in CIMBT plan quality for lead compensator thicknesses of above 100 microns, thus a 100 micron compensator
thickness constraint could be applied to the compensator optimization andmanufacturing process. Plan quality converged with 11.25◦ azimuthal and
2 mm longitudinal compensator segment increments. Compensators can be
rapidly generated from laser- or chemical-etched plastic substrate that is filledwith lead or tungsten powder and laminated, or using printed circuit board
technology.
Conclusions: We have demonstrated the promise of CIMBT using simple
dose calculation, optimization, and tumor models. Future studies considering
more complicated tumor volumes are underway, and hardware for a CIMBT
prototype is currently under development.

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160 oral
INTER FRACTION VARIATION OF HIGH DOSE REGIONS IN OAR
IN MR IMAGE BASED CERVIX BRACHYTHERAPY USING RIGIDREGISTRATION.
S. Jamema1 , U. Mahantshetty2 , V. Jagtap2 , P. V. Chitra3 , S. Kadam1 , D.
Deshpande1 , S. K. Shrivastava2
TATA M EMORIAL H OSPITAL, Medical Physics, Mumbai, India
2
TATA M EMORIAL H OSPITAL, Radiation Oncology, Mumbai, India
3
TATA M EMORIAL H OSPITAL, Mumbai, India

1

Purpose: To quantify the inter fraction variation of spatial location of highdose regions of OARs in MR image based cervix Brachytherapy using rigid
registration algorithm
Materials: Ten previously treated patients were evaluated. Each patient had
two applications (MR1 & MR2) with Vienna applicator. Volumes were delineated based on GEC ESTRO recommendations. Standard loading plan was
done for MR1 and MR2 without any form of optimization (Eclipse v 8.9). The
volume of each of the OAR (rectum, bladder and sigmoid) receiving the doseof D0.1cc, D1cc, D2cc, D5cc and D10cc in MR1 and MR2 were generated.
Co registration was performed between MR1 and MR2 with applicator as thereference (Rigid registration algorithm v 8.6.14). Based on the registration,
the overlapping volumes between MR1 and MR2 for each of the OAR for
various dose regions were quantified
Results: Table gives the overlapping dose volumes for various OARs anddose regions. D1cc overlapping was found only for rectum and the mean(SD)volume was 0.2(±0.04)cc. Highest volume of overlapping was found for rectum, as mean D2cc overlapping volume was 0.8(±0.1)cc as compared to0.4(±0.04)cc for bladder and 0cc for sigmoid. Figure shows the saggital section of D2cc overlap region of rectum in red, magenta: MR1, green:MR2. For
sigmoid, overlapping volume was found in D5cc and D10cc and is of the order of 2.00cc. The mean volume of OARs in MR1 and MR2 were 55(±6)cc
vs 60(±7)cc for bladder (p=0.3), 29(±4)cc vs 32(±3)cc for rectum (p=0.4)
and 21(±6)cc vs 23(±7)cc for sigmoid(p=0.1). The mean D2cc dose in MR1
and MR2 were 5.2(±0.7)Gy vs 4.6(±1.5)Gy for bladder (p=0.3), 3.7(±0.9)Gy
vs 3.2(±1.1)Gy for rectum (p=0.2) and 3.4(±0.8) and 2.9(±1)Gy for sigmoid(p=0.0.2). This evaluation shows that the inter-fraction dose to rectum isreproducible not only in dose quantity, but also spatially and hencecan be additive. In bladder, the overlap region is of the order of 0.5cc for D2cc and 1.5cc
for D5cc, which may suggest that the inter-fraction dose quantity may be reproducible, but not spatially. Hence direct addition of D2cc of bladder doses
may not be warranted to evaluate the total dose. In the case of sigmoid, theoverlapping dose was of the order of 2cc for D10cc, which may attribute toorgan motion which needs further review. The limitation of this study arises
from the following uncertainties: inter fraction variation of application, organ
motion, registration and accuracy of small volume DVH. Future studies havebeen planned with new registration algorithms to reduce uncertainties.

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Symposium
ESTRO – JASTRO Joint Symposium: What is thelevel of evidence needed in Particle Therapy?
161 speaker
CONSIDERABLE DIFFICULTY IN RCTS WITH PROTON BEAM
THERAPY –WHICH CANCER STATUS IS APPROPRIATE?H. Sakurai1
1
P ROTON M EDICAL R ESEARCH C ENTER AND T SUKUBA UNIVERSITY,
Radiation Oncology, Tsukuba, Japan

Conclusions: Quantification of inter fraction variation of spatial location ofhigh dose regions of the OARs using rigid registration algorithm has been
attempted. Overlap volume of D2cc region of rectum was more than the
bladder, while no overlap was found for sigmoid. Clinical relevance and implications need to be studied further.

From our experience of approximately 3000 cases treated by proton beam
therapy (PBT) at the Proton Medical Research Center (PMRC) of the University of Tsukuba, I would like to discuss the difficulties in conducting randomized clinical trials (RCT) on PBT. Recently, the complete lack of RCTs comparing PBT with X-ray therapy was pointed out mainly by physicians involved
in research on the so-called high-tech X-ray therapy. First, with the recent
technological innovations in radiation therapy, let me consider whether there
have been enough RCTs, comparing conventional radiation therapy with hightech X-ray therapies such as stereotactic radiosurgery (SRS) and intensitymodulated radiation therapy (IMRT). Although numerous phase I and phase
II trials were conducted during the development of high-tech X-ray therapies,
there are almost no reports of phase-III RCTs with two radiation therapy arms,
to compare old techniques with the new highly encouraging ones.
needless to say, promoting RCTs on PBT is unethical rather than unnecessary for tumors that are absolute indications for PBT, such as a pediatric cancer. For early-stage lung cancer, sterotactic body radiation therapy (SBRT)
is the standard treatment, and a high local control rate of over 90 % with a
low incidence of side effects has been reported. Similarly, localized prostatecancer can be treated by sophisticated IMRT with a high local control rate
and a low incidence of side effects. From the viewpoint of radiation dose distribution, the dose to the target is similar in both modalities, however, low to
medium dose delivery to the surrounding normal tissues is greater in X-ray
therapy than in PBT. Under this circumstance, where a high tumor control
rate with a low incidence of side effects has been demonstrated with hightech x-ray therapies, the advantage of an experimental arm for PBT might below. RCTs should ideally be performed to show equivalence or non-inferiority,
rather than superiority. To put it simply, such a trial would be more likely toprove expensive PBT to be non-inferior to the less-expensive high-tech X-ray
therapies.
Treatment of hepatocellular carcinoma (HCC) is a good model to demonstrate the advantages of PBT. In most cases, HCC develops in a backgroundof cirrhosis of the liver with associated liver insufficiency, and it is essential
for any therapy employed for the treatment of HCC to spare uninvolved livertissue, to minimize the risk of further impairment of the hepatic function. Recently, SRBT was demonstrated to yield good results in the treatment of small
HCCs, however, PBT demonstrated better results significantly even if the tumors treated by PBT was bigger. For HCC treatment, there is no reason toirradiate any liver tissue that is judged not to contain malignant cells. In thiscircumstance, a RCT of SBRT vs. PBT is not necessary.
What about RCTs including PBT in multimodality therapy, especiallychemoradiation? I think it is an important research area for further development of PBT. We are considering the approach into chemoproton therapy for
locally advanced cancers, such as esophageal and lung cancer. In cases withthese tumors, the local control rate achieved using conventional chemoraidation is not adequate, and side effects are considerable. chemoproton therapy
seems to yield superior results in terms of both the tumor control rate and theincidence of side effects. Considering RCTs from the ethical point of view,
could we say that both arms with different normal tissue dose delivery anddifferent tumor dose delivery should be judged to be substantially equivalent
for the patients? Furthermore, if chemoproton therapy were to be proved
to be superior, namely, chemoproton therapy established as standard therapy rather than chemoradiation therapy, could numerous patients with thesecommon diseases be treated by such expensive standard therapy?
Instead of X-ray therapy, comparison of PBT with non-radiotherapeuticmodalities for local treatment, such as surgery, radiofrequency ablation (RFA)
is possibly appropriate. For example, RCTs comparing PBT with surgery, not
SRBT, in the treatment of HCC could possibly be designed.
At present, the PMRC at the University of Tsukuba is conducting 6 ongoing clinical trials, however, none of the clinical trials involve comparison with
X-ray radiotherapy, and all are non-randomized studies. At present, I think
we do not need randomized trials to demonstrate that PBT is superior to Xray therapy. As mentioned previously, the designing of RCTs could involve
considerable difficulty, both ethically and socially, just like very few RCTs arebeing conducted to compare high-tech X-ray therapies with conventional Xray therapy.

M ONDAY, M AY 9, 2011162 speaker
IS PROTON THERAPY MAGIC?
R. Lee1
1
D UKE U NIVERSITY M EDICAL C ENTER, Radiation Oncology, Durham, NC,
USA
Proton enthusiasts claim that protons are superior to photons. In science, theburden of proof falls upon the claimant. The burden of proof is the obligationof a party in an epistemic dispute to provide sufficient warrant for their position. In medicine, by convention and community standards, this burden isconventionally met by rigorous randomized trials. To aver that proton therapy
does not require this level of evidence implicitly suggests that proton therapy
is supernatural, beyond the limits of the natural world; in short, magic. In
this presentation I will assume the position of a true skeptic. The true skeptic takes an agnostic position, one that says a claim is "not proved" rather
than disproved. The true skeptic asserts that the claimant has not borne theburden of proof and that science must continue to build its cognitive map ofreality without incorporating the extraordinary claim as a new "fact." Since thetrue skeptic does not assert a claim, he has no burden to prove anything.
163 speaker
TUMOR SITES TO BE SELECTED FOR COMPARISON OF CARBONIONS VS PROTONS
H. Tsujii1
1

N ATIONAL I NSTITUTE OF R ADIOLOGICAL S CIENCES (NIRS), Biology,
Chiba, Japan
Abstract not received.

164 speaker
WHAT TUMOUR SITES SHOULD BE SELECTED FOR RANDOMISEDTRIALS?
J. Debus
Abstract not received.

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Proffered paper
Clinical Proffered Papers 2: Rectal Cancer
165 oral
POSTOPERATIVE CHEMORADIOTHERAPY IMPROVES SURVIVALAFTER D1 LYMPHADENECTOMY OR R1 RESECTION IN GASTRICCANCER
M. Verheij1 , J. Dikken2 , E. Jansen1 , H. Hartgrink2 , H. Putter2 , H. Boot1 , A.
Cats1 , C. van de Velde2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands
2
L EIDEN U NIVERSITY M EDICAL C ENTER, Leiden, Netherlands

1

Purpose: The Intergroup 0116 phase III study showed that postoperative
5-fluorouracil-based chemoradiotherapy (CRT) improves locoregional control
and overall survival (OS) in gastric cancer. We have recently studied thefeasibility of more intensified CRT schedules in three phase I-II trials. The
purpose of the present study was to compare the patterns of recurrence andsurvival in these studies with those from the Dutch Gastric Cancer Group Trial(DGCT) that randomized patients between D1 and D2 lymph node dissection(LND).
Materials: From 2001 to 2008, 94 patients with gastric adenocarcinoma
underwent surgery followed by irradiation of the gastric bed, anastomoses
and lymph nodes (25 x 1.8 Gy) combined with capecitabine and cisplatin(n=42), capecitabine (n=47), or 5-fluorouracil and leucovorin (n=5). Recurrence and survival patterns were compared with 649 patients from the DGCT
who underwent radical resection with a D1 (n=352) or D2 (n=297) LND. Differences were calculated with Cox-regression after adjustment for several covariates: age, sex, tumor localization, Lauren classification, T-stage, N-stage,
total/subtotal gastrectomy, splenectomy, pancreatectomy, type of LND andradicality (R0/R1).
Results: With a median follow up of 27 months in the CRT group, patientswith a microscopically irradical (R1) resection had a significant benefit in 2year OS after CRT (68% vs 30%, p<0.01) and a decreased LRR rate (3% vs21%, p=0.02). CRT patients who underwent a D1 dissection (n=41) vs DGCTD1 (n=352) showed a significant benefit in 2-year OS for the CRT-group (83%vs 73%, p=0.04) with a significant decrease in LRR (2% vs 18%, p<0.01).
Analysis of CRT-D2 (n=25) vs. DGCT-D2 (n=297) revealed no significant differences. Regional recurrences (peritoneal carcinomatosis) were found more
often after CRT (7% vs. 3%, p=0.01).
Conclusions: In this updated study, postoperative chemoradiotherapy compared to surgery alone showed an increased 2-year OS after a D1 dissection,with a decrease in LRR. Patients with an R1 resection also benefit in 2-year
OS after CRT. These non-randomized results indicate that postoperative CRT
increases survival, specifically after a D1 LND or an R1 resection. The CRT
regimen together with preoperative chemotherapy is currently evaluated in aphase III study (CRITICS; Clinicaltrials.gov NCT 00407186).
166 oral
GASTRIC MALT LYMPHOMA: LONG-TERM EXCELLENT OUTCOME
OF 103 PATIENTS TREATED WITH RADIOTHERAPY ALONEJ. Yahalom1 , S. Lovie1 , P. Bonner1
1
M EMORIAL S LOAN -K ETTERING C ANCER C ENTER, Radiation Oncology,
New York, USA
Purpose: In North America, low-dose involved field radiotherapy (IFRT)
alone has emerged as the standard of care for patients with H. pyloriindependent gastric MALT lymphoma (GML). In Europe, treatment approaches vary, and systemic therapies and/or gastrectomy are often recommended as alternatives. We analyzed two decades of experience with a large
cohort of GML patients treated with IFRT and followed regularly with endoscopic biopsies.
Materials: From 1992-2009, we treated with IFRT 103 consecutive patientswith GML stage I (76%), stage II (20%) or stage IV (4%). 84% had no evidence of H. Pylori infection at diagnosis; the remaining had persistent lymphoma after antibiotic treatments and adequate observation. Prior to RT, 4
had partial gastrectomy and 7 had systemic therapy that failed to control their
GML. Median age was 62 years (range: 25-91). 58% were women. Median
IFRT dose was 30 Gy (range: 22.5-43.5). Following IFRT, 98% had endoscopic biopsies, for most, gastric biopsies were performed throughout theirfollow-up. Median follow-up was 5.5 years (22% >10 yrs; maximal-16 yrs).
Results: 98/101 (98%) patients obtained biopsy-proven complete response.
8 patients relapsed in the stomach 2 within a year with DLBCL, both received
chemotherapy (1 had CR, 1 died of complications). 6 relapsed with GML. Of
those, 2 had also H. Pylori and obtained a CR to antibiotics alone. 1 had CR
to additional IFRT, 1 CR to rituximab, 1 CR to chemotherapy and only 1 is under close observation with asymptomatic residual disease. 10-year actuarial
freedom-from-local failure was 93+ 3%. 10-year overall survival was 74+6%.
6 patients developed lymphoma in extra-gastric sites (MZL-3, DLBCL-2, FL2, SLL-1). 2 patients were diagnosed with carcinoma of the stomach at 1
and 5 years after RT. 3 other patients developed second tumors close to RT

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field (colon-1; pancreas-2; at 3, 8 and 11 years, respectively). Most otherdeaths appeared unrelated to GML or RT, in some cause of death was not
fully detailed. IFRT was well tolerated with no acute or chronic complications
with the exception of a single patient who developed antral stricture requiring
gastro-jejunostomy.
Conclusions: Mature results of a large cohort of unselected patients with
H. pylori-independent GML support the choice of low-dose local RT as a welltolerated, safe and effective treatment. It allows stomach preservation, spares
systemic toxicity and is curative for over 90% of patients.
167 oral
PREOPERATIVE RADIOTHERAPY AND LOCAL EXCISION OF
RECTAL CANCER: RESULTS OF A RANDOMIZED STUDY
K. Bujko1 , P. Richter2 , W. Polkowski3 , M. Szczepkowski4 , T. Gach2 , G.
5

6

5

5

3

Nawrocki , A. Dziki , J. Kusnierz , J. Radziszewski , R. Wierzbicki , L.
Pietrzak1 , M. Kolodziejczyk1 , D. Dymecki7 , A. Radkowski8 , W. Meissner9 ,K. Paprota10 , A. Rychter11
1
M ARIA S KLODOWSKA -C URIE M EMORIAL C ANCER C ENTRE AND I NSTITUTEOF O NCOLOGY , Department of Radiotherapy, Warsaw, Poland
2
J AGIELLONIAN M EDICAL U NIVERSITY C OLLEGE, Department of Surgery,Krakow, Poland
3
M EDICAL U NIVERSITY OF L UBLIN, Department of Surgical Oncology,
Lublin, Poland
4
S ZPITAL B IELANSKI, Clinical Department of General and Colorectal
Surgery, Warsaw, Poland
5
M ARIA S KLODOWSKA -C URIE M EMORIAL C ANCER C ENTRE AND I NSTITUTEOF O NCOLOGY , Department of Oncology, Division of Surgery, Warsaw,
Poland6
M EDICAL U NIVERSITY, Department of Colorectal Surgery, Lodz, Poland
7
M EDICAL U NIVERSITY, Department of Colorectal Surgery, Poznan, Poland
8
R EGIONAL C ANCER C ENTRE, Department of Radiotherapy, Tarnow, Poland
9
M EDICAL U NIVERSITY, Department of Surgery, Poznan, Poland
10
R EGIONAL C ANCER C ENTER, Department of Radiotherapy, Lublin, Poland
11
C OPERNICUS M EMORIAL H OSPITAL , R EGIONAL C ANCER C ENTRE,
Department of Radiotherapy, Lodz, Poland
Purpose: To assess local control after preoperative radiation and fullthickness local excision for rectal cancer and to determine an optimal radiotherapy schedule in a multicentre study.
Materials: The eligibility criteria: G1-2 rectal adenocarcinoma <3-4 cm; flat
raised cT1, cT2 or borderline cT2/cT3; cN0. Mucosa at the tumour edges
was tattooed. Patients were randomized either to 25 Gy in 5 fractions over
one week plus 4 Gy boost or to chemoradiation - 50.4 Gy in 28 fractions plus
5.4 Gy boost in 3 fractions given concurrently with 5-Fu and leucovorin. Local
excision was performed 6 weeks later. Patients downstaged to ypT0-1 category with negative margins (primary endpoint) were followed-up. Immediateconversion to a transabdominal surgery was recommended for remaining patients. Rescue surgery was planned for those with local recurrence.
Results: Due to a poor accrual, the trial was closed prematurely in October 2010. Of 89 patients (cT124%, cT263% and cT2/cT314%) who fulfilled
the entry criteria and underwent both preoperative radiation and local excision(with the use of the retractor 57%, endoscopic microsurgery 40%, and Kraske
procedure 2%) there were 29 patients randomly allocated to the short-courseradiation and 22 to the chemoradiation: 38 patients were not randomized.
The latter patients fulfilled the entry criteria and were treated using the methods described in the protocol, mostly the short-course radiation due to the
comorbidity precluding chemotherapy. In the intention-to-treat analysis of therandomized patients, 62% and 86% of patients did not require conversion
in the short-course and in the chemoradiation group, respectively, p=0.066;
pathologic complete response rate (unplanned analysis) was 38% and 55%,
for short-course and chemoradiation group, respectively, p=0.238. In the perprotocol analysis of the total group of patients, the corresponding figures were66% and 80%, p=0.185; 34% and 64%, p=0.011. Of 27 patients who required
conversion, 9 actually underwent this procedure and 18 were unfit or refused.
The median follow-up was 24 months (range 2-84). Distant metastases occurred in 9% of patients. Of 62 patients who did not require conversion, theincidence of local recurrence was 8% (7% in the short-course group and 10%
in the chemoradiation group). In 18 patients (ypT2 56%, ypT3 28%, ypTx,
positive margin 17%) who required but did not undergo conversion, the incidence of local recurrence was 44%.
Conclusions: Trend towards better effectiveness of chemoradiation compared to short-course radiation was demonstrated. In good responders toradiotherapy, the local control appears to be acceptable. Longer follow-up isneeded for final conclusions.

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169 oral

THE ADDED VALUE OF TEXTURE- AND SHAPE-BASED FEATURESFROM CT-IMAGING FOR RESPONSE PREDICTION IN LOCALLYADVANCED RECTAL CANCER
R. van Stiphout1 2 , H. Aerts1 , M. Janssen1 , G. Lammering1 , E. Postma3 , P.

TARGET VOLUME DELINEATION VARIATION IN PRE-OPERATIVERADIOTHERAPY OF EARLY-STAGE RECTAL CANCER
J. Nijkamp1 , D. de Haas-Kock2 , J. Beukema3 , C. Marijnen41

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands
MAASTRO CLINIC, Radiation Oncology, Maastricht, Netherlands
3
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Oncology, Groningen, Netherlands
4
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Clinical Oncology,
Leiden, Netherlands

Lambin11
MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS TRICHT, Department of Radiation Oncology, Maastricht, Netherlands
2
M AASTRICHT U NIVERSITY, Department of Knowledge Engineering,
Maastricht, Netherlands
3
T ILBURG U NIVERSITY, Tilburg centre for Cognition and Communication,
Tilburg, Netherlands

2

Purpose: After the Dutch TME trial, pre-operative radiotherapy (RT) has
been added to the standard of care in the treatment of early stage rectal cancer. Although local control improves, RT comes with an increase in toxicity.
IMRT can be used to increase dose conformity, reducing the toxicity. These
conformal dose distributions are less forgiving for errors in target volume definition. To facilitate introduction of IMRT nationwide we have conducted anational study to determine the target volume delineation variation, establish
the target volume and diminish the delineation variation.
Materials: Eight patients with early-stage rectal cancer were selected, 4 witha tumor less than 5 cm from the anal verge, and 4 with a distance of > 5 cm.
The dataset, together with the clinical data, was sent to 24 GE-RT oncologists in 21 institutes for clinical target volume definition, without delineation
instructions (phase 1). After observer variation analysis a workshop was organized to establish definition guidelines and an electronic delineation atlas.
Seven months later the same observers re-delineated the same dataset using the guidelines and atlas (phase 2). Delineation variation was analyzed
in terms of variation in volume, most caudal and cranial slice, conformity index between each observer and median volume of each patient and by local
surface distance variation.
Results: Of the 24 observers, 11 completed both the 1st and 2nd phase. The
average delineated target volumes significantly decreased for both the low(p<0.001) and high (p=0.05) seated tumors (Table 1). For the low seatedtumors also the volume variation between observers significantly decreased
from 139 cc to 90 cc (p=0.01). Variation in the most caudal delineated slice
was improved to around 1 cm 1SD, while the definition of the cranial slice
did not improve. Due to the reduction in delineated volume the conformity
index only slightly increased. Analysis of the local surface distance variation
revealed that most initial delineation variation was found at the anterior sideof the CTV, close to the major organs at risk, and at the sphincter region.
Especially in these regions the observer variation was significantly reduced.

Purpose: For locally advanced rectal cancer (LARC) an early accurate prediction of tumour response after preoperative chemoradiotherapy (CRT) is
valuable to tailor treatment. In literature, response prediction for LARC ismainly based on PET-imaging, and specifically the maximal standard uptake
value (SUVmax). In this study, the addition of CT-based features to PETimaging is evaluated for pre-treatment response prediction in LARC.
Materials: In total, 198 LARC patients from Maastro clinic were included,
accrued between 2005 and 2009. All patients received CRT (28 x 1.8 Gyradiotherapy + Xeloda chemotherapy) and surgery (two months after CRT).
The tumours were semi-automatically contoured based on the pre-treatment
PET-scan using a signal-to-background based threshold method (Figure 1A).
Only SUVmax was evaluated from the PET scan. From the CT-scan, 60 features were extracted, including 13 first-order gray-value statistic features, 10
shape features, 26 gray-level co-occurrence matrix (GLCM) features and 11
gray-level run-length (GLRL) features (Figure 1B). Responders were definedas patients with a yielded pathological staging group of ypT012N0 based on
pathology reviews of the resected specimen. First, predictors were identified
using univariate analysis (Wilcoxon signed-ranks test, a = .05). Significant
predictors were included in a multivariate model based on logistic regression
to predict tumour response. Performance of the model was expressed as the
AUC (Area Under the Curve) of the Receiver Operating Characteristic (ROC).
Results: The occurrence of responders in the dataset was 50.5%. The AUCof the prediction model only based on SUVmax was 0.58, while the additionof extra imaging features resulted in a significant increase in AUC to 0.70 (Figure 1C). Next to SUVmax, nine additional significant predictors were found,based on tumour shape (compactness, maximum diameter, surface area, volume and spherical disproportion), first-order histogram statistics (total energy,
root-mean-square), and one GLRL feature: run percentage.

Figure 1. A. Signal-to-background PET-based contouring. B. 3D visualizationof PET contour. C. ROC curves for the response predictions with SUVmax(dotted line) and with SUVmax and additional CT-based features (solid line).
Conclusions: The addition of extra CT-based imaging features to PETimaging results in more accurate models for pre-treatment prediction of tumour response. External validation and data from multiple time-point scans
will be presented.

Conclusions: National consensus guidelines for target volume delineation inearly stage rectal cancer have been established. With the guidelines and anelectronic atlas variation between different observers from different institutes
was significantly reduced. Besides more consistent target definition, the volumes were also significantly smaller. With the consensus guidelines we are
now closer to introduction of IMRT for reduction of dose to the organs at risk,
but delineation variation is still substantial.
on behalf of the Dutch National Platform for Gastroenterology Tumors

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M ONDAY, M AY 9, 2011170 oral
TOWARDS A LYON MOLECULAR PROGNOSTIC SIGNATURE FOR
RECTAL CANCER
J. Doyen1 , E. Letouze2 , P. Romestaing3 , O. Chapet4 , J. P. Gérard1
1
C ENTRE A NTOINE L ACASSAGNE, Department of Radiotherapy, Nice,
France2
L IGUE CONTRE LE C ANCER, Paris, France3
H ÔPITAL P RIVÉ M ERMOZ, Department of Radiotherapy, Lyon , France
4
C ENTRE H OSPITALIER LYON S UD, Department of Radiotherapy, Pierre
Benite, France
Purpose: Tailored treatment is increasingly popular in multimodality approach of cancer. In rectal cancer although some molecular biomarkers havebeen described,none so far have been used in clinical practice. We report aprospective translational research aiming at identifying such new prognostic
biomarker.
Materials: Between 1998-2001 a series of 94 patients with rectal
adenocarcinoma(T1-2-3 M0) was treated in Hopital Lyon Sud with preoperative radiotherapy(RT) with or without concurrent chemotherapy(CT)(78 pts)
or With curative RT alone using contact X Ray therapy (CXRT)(18 pts). All
these patients were included in a translational research program with tumor
biopsy taken at time of rectoscopy before treatment by 2 oncologists (PR,
JPG) . All specimen were frozen (-80 ◦ C).Highthroughput analysis of genomics imbalances (cgh hr illumina beadchips-Evry) and DNA expression (affimetrix chips-illkirch) were performed within the frame of the "Carte d’Identits
Tumeurs (CIT) programme of Ligue du Cancer- France. Biostatistical analysis
were performed and biomolecular results were matched with rate of distantmetastases and specific survival. Mulivariate analysis was performed.
Results: The median survival of the 96 patients was 105 months. The overall
specific survival rate at 8 years was 75% for the preop group and 65 % for the
RT alone group. Overall the rate of distant metastases was 30 % at 8 years (26 pts). A validated biopsy specimen was analysed in 67 pts for DNA expression and for genomic imbalance. Expression of two genes was significantly
associated with specific survival. Most of all a very significant correlation was
found with metastases rate and specific survival with one chromosomal deletion (fig 1)Two other significant correlations were found with 2 chromosomal
abnormalities(p:0.017 and p:0.019). A patent procedure is ongoing for thesemolecular biomarkers and definitive validation will be performed on the initial paraffin embedded blocs and on a large series of rectal cancer throughimmunohistochemistry.
Conclusions: Taking advantage of an homogeneous series of patients witha long follow up we have been able to identify a series of biomarkers able
to predict with a high accuracy the risk of developing distant metastases.
Identification of these biomarkers will be presented at time of the meeting.

M ONDAY, M AY 9, 2011172 oralPhysics Proffered Papers 3: Highlights
171 oral
REALIZATION OF THE ABSORBED DOSE TO WATER FOR I-125
INTERSTITIAL BRACHYTHERAPY SOURCES
T. Schneider1 , H. J. Selbach1
1
P HYS . T ECHN . B UNDESANSTALT (PTB), Dosimetry for radiation therapy
and diagnostic radiology, Braunschweig, Germany
Purpose: Within the EURAMET joint research project ’Brachytherapy’ National Metrology Institutes (NMI’s) in Europe are developing new primary
standards for the absorbed dose to water (Dw) for Low Dose Rate (LDR)
brachytherapy which will replace the current reference air kerma rate (RAKR)
standards in the future. The aim is to improve the accuracy and effectivenessof the dosimetry of brachytherapy to a level comparable to that of radiotherapy
with external beams.
Materials: The German national metrology institute (PTB) decided to base its
primary standard on an extrapolation chamber (EXPO) in a phantom of water equivalent material, as, due to its higher sensitivity, ionometric methods
seem to be the preferred choice. The first idea was to use an existing method
to determine Dw from extrapolation chamber measurements based on the’wall-less chamber approximation’ and the approach to extrapolate linearly
from the conditions of secondary electron equilibrium.However, from the firststudies it turned out that the existing method is not adequate. As a consequence a method was newly developed based on radiation transport theory.
The new method offers a clear analytical expression to determine Dw. A
conversion factor C(xi, xi+1) has to be applied to the difference of ionization
charges measured at two plate separations xi and xi+1. This factor is composed of quotients of kerma values calculated for different plate separationsin the chamber. It has been shown in a recent publication that this conversion
factor is robust against uncertainties of database and spectra in comparison
to conversion factors needed to convert the RAKR into Dw. The uncertainties of the conversion factors could be reduced from 10 % (RAKR) to 1 %(EXPO).The prospective primary standard is a large, air-filled, parallel-plate
extrapolation chamber in a phantom of water-equivalent material (RW1). The
thickness of the entrance plate defines the measurement depth within the water phantom and the inner side of the front plate the reference plane of thechamber. The back plate of the phantom was chosen to be 60 mm in thickness to represent a phantom of infinite thickness for the radiation concerned.
The measuring volume of the chamber is given by the collecting electrodewith a diameter of 100 mm and the plate separation which may amount up to
200 mm.

NORMAL TISSUE REACTION OF THE LIVER AFTER STEREOTACTIC
RADIOTHERAPY(SBRT)
DETERMINEDBY
18FLUORODEOXYGALACTOSE AND PET/CT-SCANNING
1
2
3
1
3
M. Hoyer , M. Sørensen , J. Petersen , M. I. Holt , L. P. Muren , S.

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in 58% of cases (113/196), modifications were partly or completely acceptedby the treating radiation oncologist. At least one of the OARs was delineatedand submitted in 95% of the cases, where only 37% of them were modified.

Keiding2
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus
Hospital, Aarhus C, Denmark
2
A ARHUS U NIVERSITY H OSPITAL, PET center, Aarhus C, Denmark
3
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
1

Purpose: The normal tissue tolerance following standard fractionation radiotherapy is well established. However, there is very limited data on normal
tissue reaction in liver following hypofractionated irradiation as in the case of
SBRT. Hepatitis B or cirrhosis is frequent among patients treated by SBRT forliver tumors and both conditions are related to increased risk of severe reaction. Methods based on measurements of hepatic blood perfusion by dynamic
contrast enhanced CT and SPECT based methods are hampered by their
indirect nature and poor spatial resolution. We have developed a PET/CT
based method for quantitative 3D measurements of liver metabolic function.
This method is being further developed for functional treatment planning.
Materials: The method is based on IV infusion of 18-Fluoro-deoxy-galactose(FDGal) which is almost exclusively metabolized in the liver and PET/CTscanning. Deformable image co-registration was used in analysis of changes
in regional FDGal uptake on pre- and posttreatment PET/CT and in the comparison of these to the dose levels on the treatment planning CT scan.
Results: The 18FDGal PET/CT procedure was developed in a pig modeland has now been tested in 7 patients treated with SBRT with a central doseof 45-56.25 Gy in a 3 fraction schedule for a variety of liver tumors. We
found a dose dependent decrease in FDGal uptake, with features of uptake
on the PET scan closely conforming to the isodose lines of the treatment plan.
Uptake was reduced by 16% (range 0-28%) in liver receiving 15 Gy and 43%(range 9-63%) in 30 Gy volumes. The liver function was almost normalized on
the 3 month FDGal PET/CT scan. Normal liver receiving less than 5 Gy had
a very constant pattern of uptake during the 3 month. A treatment planningstudy indicates that functional-image based treatment planning by use of the
FDGal PET/CT allowed sparing of the best functioning normal liver by as highas 55% at dose levels at 15 Gy or higher.
Conclusions: The present study shows that it is possible to determine
radiation-induced alteration in liver function in 3D by use of FDGal PET/CT.
Pre-treatment FDGal PET/CT may be useful in selection of patients suitablefor SBRT for liver tumors and early measurement of liver function during fractionated treatment may possibly be used for treatment adaptation. Furthermore, functional-image based treatment planning based on FDGal PET/CT
may have a future role in SBRT and conformal radiotherapy for liver tumors.
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PROCARE /RT PART/: IMPROVING CARE OF RECTAL CANCER IN
BELGIUM BY STANDARDIZING CTV DELINEATION
E. Hortobagyi1 , M. Lambrecht1 , J. Verstraete1 , P. Scalliet2 , K.
Haustermans1
U NIVERSITY H OSPITAL G ASTHUISBERG, Leuven, Belgium
2
UCL C LINIQUES U NIV. S T.L UC, Brussels, Belgium
1

Results: The details of the method as well as of the design will be presented.
The determination of Dw of an I-125 seed will be demonstrated by the measurement of a ’BEBIG Symmetra I25.S06’- seed. The results will be compared to the results obtained by RAKR measurements with the PTB primary
standard chamber GROVEX I and a conversion to Dw using the formalism of
TG-43.
Conclusions: The expected benefits of the new method in comparison to
RAKR measurements will be discussed for the source investigated and forother sources applied in LDR brachytherapy as well as for miniature x-ray
sources.

Purpose: The aim of PROCARE (PROject on CAncer of the REctum) -a Belgian multidisciplinary project- is to improve quality in all aspects of the treatment chain (surgery, pathology, radiology, radiotherapy etc), thus improving
outcome in patients treated for rectal cancer. We present the implementation of the radiotherapy part of this project and highlight the role of radiation
technologist (RTT) participation in central review of radiotherapy (RT) volume
delineation.
Materials: A central review facility requiring specific software (Aquilab,
France) installation at each participating center and a secure network connection between them was established. All rectal cancer patients’ planning
CT’s with delineated clinical target volumes (CTV) and organs at risk (OAR)
are submitted for review prior to the start of RT. Together with published target volume delineation guidelines (Roels et al., IJROBP 2006), consensus
organ at risk (OAR) contouring instructions were developed. Review is performed by a specially trained RTT under the supervision of the two radiation
oncologist project leaders. The evaluation may result in suggestions for CTV
modifications; however, acceptance of all or some of these changes is at thediscretion of the local treating physician. The CTV which is ultimately used forpatient treatment is then resubmitted to the central database. The delineationof the suggested OAR and their submission to central review remains on a
voluntarily basis; however in case the OARs are submitted, they are includedin the evaluation.
Results: In the first half of 2010, the first four site installations tested the review software, network connectivity and the review procedure. After this successful pilot phase, 15 additional institutions joined the PROCARE RT project.
By 30/11/2010, central review of 282 patients from 16 centers has been performed (Table 1). In 70% of CTVs, at least one change was suggested, andConclusions: The PROCARE Radiotherapy project is running smoothly between the reviewer sites and the participant centers.This project demonstrates that a well-trained RTT can play a major role in central review of RT
volumes, can assist in treatment standardization and can reduce the workloadof radiation oncologist reviewers. Retrospective analysis of CTVs ultimately
used in patient treatment will be performed illustrating the most frequent modifications. In addition, we expect a learning curve in each department. Therefore, the need for CTV corrections should decrease in time at every centre
that has submitted at least 10 or more CTV’s for correction. The idea is toshow that the repetitive corrections actually improve the quality of the delineated CTV over time.
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ENHANCED 4D PET OPTIMIZATION BASED ON 4D CT MOTIONMODELING
C. Gianoli1 , G. Fontana1 , M. Riboldi1 , C. Cavedon2 , G. Baroni1
1
P OLITECNICO DI M ILANO U NIVERSITY, Milano, Italy
2
A ZIENDA O SPEDALIERA U NIVERSITARIA I NTEGRATA, Verona, Italy
Purpose: The purpose of the study is to evaluate the performance of a novel
strategy aiming at the optimization of 4D PET count statistics, referred to as"virtual 4D PET strategy".
Materials: The proposed optimization of 4D PET count statistics is based on
4D CT motion modeling as resulting from deformable image registration. The"virtual 4D PET strategy" leads to the generation of a 4D PET starting fromthe 3D free breathing PET, with no requirement of specific time resolved PET

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data acquisition. The technique consists of two steps: (1) computation of
deformation fields, by registering a phase-averaged 4D CT image (3D) onto
each phase of the 4D CT acquisition; (2) warping of the free breathing PET toa 4D volume according to the deformation fields defined from the 4D CT motion model (Figure 1). The "virtual 4D PET strategy" strategy was tested on
the 4D NCAT (Nurbs-based Cardiac-Torso) phantom. The synthetic images
generated by NCAT were low-pass filtered and blurred with noise. Breathing
motion was simulated in the phantom with 2 cm peak to peak displacement of
the diaphragm and 1,2 cm antero-posterior chest expansion. A 2 cm spherical lesion was placed into the right lung with a tumor to background ratio in
PET equal to 18,75. Quantification was focused on lesion PET segmentation
by assessing the relative overlap, normalized with respect to the reference
image, between the segmented lesion on the virtual 4D PET and the known
characteristics of the synthetic lesion generated in the NCAT phantom.

Results: Results for the newly designed strategy were compared to motion
compensation in conventional 4D PET acquisitions, according to the deformation between phases. The mean overlap for the "virtual 4D PET strategy"
was 94.2 %, whereas motion compensated PET resulted in a 98.1% overlap.
Both strategies were able to significantly recover the simulated lesion motion,that was designed so that the overlap between exhale and inhale was minimal(0.92%) in the 4D PET image. The overall uncertainties were found to correlate to the amount of deformation due to breathing motion. The computationaltime for the "virtual 4D PET strategy" was reduced by a factor (N-1), where N
is the number of breathing phases, with respect to motion compensated PET.
Conclusions: The proposed "virtual 4D PET strategy" showed the potential
to optimize PET count statistics with similar performance with respect to conventional motion compensation techniques in 4D PET. The main advantages
are related to the computational cost, the coregistration restrictiveness andclinical feasibility, as no 4D PET acquisition required. The count statistics optimization can be further enhanced when considering the application to thesinogram space, in order to achieve a better image signal to noise ratio.
175 oral
DEVELOPMENT OF A COMPREHENSIVE ONLINE ADAPTIVE
SOLUTION TO ACCOUNT FOR INTER- AND INTRA-FRACTIONALVARIATIONS
A. Li1 , F. Liu1 , E. Ahunbay1 , G. Chen1 , A. Tai1 , B. Erickson1
1
M EDICAL C OLLEGE OF W ISCONSIN, Radiation Oncology, Milwaukee, USA
Purpose: Delivery of curative doses has been hampered by large margins
caused by the significant inter- and intra-fractional variations in fractionated
RT. The current IGRT repositioning cannot fully account for the organ deformation and rotation. We have developed a comprehensive solution usinggated IMRT with online adaptive replanning to manage both inter- and intrafractional variations. The implementation of this solution for pancreas RT will
be presented.
Materials: The comprehensive solution starts with the generation of a
respiration-gated IMRT plan (original plan) based on 4DCT. For each treatment, the following online adaptive replanning process is performed: 1)
acquiring daily CT in treatment position right before the treatment using adiagnostic-quality in-room CT (CTVision, Siemens) with the same gating window as that for the planning CT, 2) generating contours of target and organ at risk (OAR) based on the daily CT by auto-segmentation, 3) morphing segment apertures based on new contours and optimizing weights of the
new apertures to generate the adaptive plan, 4) computing and comparing
dose distributions between the adaptive plan and the original plan with patient repositioning, 5) transferring and performing QA tests (independent MU
calculation and validation of planning data transfer) for the adaptive plan witha software tool, and 6) delivering the adaptive plan under gating. The entire solution is validated with phantom measurements and with retrospective
dosimetric analyses for 10 selected pancreatic cancer cases.

M ONDAY, M AY 9, 2011
Results: The online adaptive replanning based on the CT of the day acquired under respiration gating can effective account for the inter- and intrafractional variations including severe organ deformations observed in pancreas RT (Fig.a). With the daily gated-CT-guided gated delivery, ITV volume
is reduced by 20% on average (Fig.b) and the intrafraction motion is <3mm.
The mean V50.4 (volume cover by 50.4Gy)for duodenum was reduced from
43% for IGRT repositioning to 16% for the adaptive scheme (Fig.c). Dosimetric benefits on OAR sparing for using the diagnostic-quality-CT based IGRT,
gating and online adaptive RT (ART) are compared (Fig.d). The adaptiveplans can be generated within 10 min. The online replanning process, eliminating the need to shift the patient, can be performed within the similar orslightly longer time frame required for the current IGRT repositioning and fits
into the routine clinical workflow.

M ONDAY, M AY 9, 2011
Results: The mean dice scores for the best template were: 64%, 66%,
74% and 43% respectively for the prostate, the rectum, the bladder and theSV.Dose differences and significance regions are represented on Fig. 1. Asin the previous study we found that the group of patient without failure received on average significantly more dose in the presacral region and in the
obturator area. However, in thus study this finding was obtained with a single
mapping instead of two separate mappings.

Conclusions: The newly developed online adaptive replanning techniquebased on daily respiration-gated diagnostic-quality CT can effectively account for inter- and intra-fraction variations. This comprehensive solution
enables "image-plan-treat", a new paradigm for IGRT that permits shrinking
PTV margins and can facilitate accurate RT delivery particularly important for
hypofractionations (e.g., SBRT) and/or dose escalations.

Fig 1. Dose difference map (on the right) and p-value map between patients
without and with failure . The dose difference map was constructed using
deformable image registration.
Conclusions: Inter-patient deformable registration allows, in principle,
straightforward comparison between dose distributions of cured and failed
patients. This is the first study using deformable registration for this purpose.
Large anatomical variations existing between patients, as well as the quality
differences of the planning CTs make the dose mapping challenging, however. We are currently optimizing the inter-patient deformable registration
accuracy, for instance by guiding the registration process with the available
delineation information.

Physics Proffered Papers 4: Dose Volume Parameters and Biological Modelling

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176 oral
DOSE MAPPING BASED ON DEFORMABLE REGISTRATION TO
RELATE DOSE OUTSIDE THE PROSTATE WITH FAILURE
G. Cazoulat1 23 , M. Witte1 , M. van Herk1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands
2
U NIVERSITÉ DE R ENNES -1, LTSI, Rennes, France
3
INSERM, U642, Rennes, France
Purpose: In a previous study, a relation between the dose outside theprostate and the tumor control for advanced stage prostate cancer patientswas found by comparing dose distributions of non-failure and failure patients.
To compare the dose distributions, dose mappings based on the distance andthe orientation of each point from the prostate or the rectum were used. The
aim of this study is to compute dose difference maps in a more general andaccurate way by means of deformable registration between study patients.
Materials: First, 50 patients from the whole trial database (669 patients) were
tested to find a template patient as close as possible to the average anatomy.
For each possible template, 30 randomly chosen patients were registeredon it: first rigidly and then in a deformable way with a "demons" algorithm.
The available delineations were deformed and compared with the templatedelineation by means of the dice score for each organ. We chose our final
template as the one giving the best compromise between the different dicescores. Next, we applied dose mapping to a subset of patients. A group of 67
patients with tumor stage T3b and T4 from the Dutch Phase III trial (CKVO 9610) was chosen. The end-point for clinical and biochemical failure was fixedat 4 year. In this group, 30 patients failed. The 67 patients were registered
to the selected template patient with the same "demons" algorithm and theirdose was deformed accordingly. From the mapped dose distributions, themean dose was computed for the two subgroups (with and without failure).
By subtracting the mean dose of patient with failure from the mean dose ofpatient without failure, we obtained a dose difference on each voxel of thetemplate anatomy. A p-value map was computed to estimate the statisticalsignificance of the dose differences.

FOCUSING ON A LONGITUDINAL DEFINITION OF LATE FECALINCONTINENCE AFTER HIGH-DOSE RADIATION FOR PROSTATECANCER: A STRONGER EVIDENCE OF CLINICAL AND DOSIMETRIC PREDICTORS
T. Rancati1 , C. Fiorino2 , G. Fellin3 , V. Vavassori4 , E. Cagna5 , G. Girelli6 , F.
Tortoreto7 , S. Delle Canne8 , R. Valdagni1
1
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Prostate
Program, Milan, Italy
2
I STITUTO S CIENTIFICO H.S. R AFFAELE, Medical Physics, Milano, Italy
3
O SPEDALE S ANTA C HIARA, Radiotherapy, Trento, Italy
4
I STITUTO C LINICO H UMANITAS -G AVAZZENI, Radiotherapy, Bergamo, Italy
5
O SPEDALE S ANT ’A NNA, Radiotherapy, Como, Italy
6
O SPEDALE C IVILE ASL 9, Radiotherapy, Ivrea, Italy
7
O SPEDALE S AN G IOVANNI C ALIBITA FATEBENEFRATELLI, Radiotherapy,
Rome, Italy
8
O SPEDALE S AN G IOVANNI C ALIBITA FATEBENEFRATELLI, Medical Physics,
Rome, Italy
Purpose: To evaluate the relationship between clinical/dosimetric factors andlate fecal incontinence (linc) after high-dose radiotherapy (RT) in prostate cancer patients (pts) accrued in AIROPROS 0102 trial (RT doses: 70-80Gy, 1.82Gy/fr).Toxicity (tox) was defined using a longitudinal definition (mlinc) whichtakes into account both severity and duration of symptoms.
Materials: Self-reported questionnaires of 586 pts enrolled with a minimum
follow up of 36 mos were analyzed. Only pts with a G0 basal linc were included (550/586). Mlinc was defined as the mean score for fecal incontinence calculated over the whole follow up period.G1 linc was scored if unintentional stool discharge was "sometimes" experienced, G2 linc was scoredif unintentional stool discharge was "often" experienced or if pts sporadicallyused sanitary pads; G3 if pts reported daily unintentional stool discharge or
use of sanitary pad >2 times/week. The correlation between pre-treatment
morbidities, hormonal therapy, drug prescription, presence of diabetes or hypertension, abdominal surgery prior to RT, presence of acute LGI tox, pelvic
nodes and seminal vesicles irradiation, mean rectal dose, DVH constraints(from V20Gy to V75Gy) and mlinc was investigated by uni- and multivariate(MVA) logistic analyses.

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Results: Mlinc is a continuous variable (range 0-2.7 in this population).
197/550 pts have mlinc>0, that is 35.8% pts experienced some linc symptoms during the follow up period. 22/550 pts have mlinc greater or equal
than 1, that is 4% pts have either a persistent G1 linc or a G2-G3 linc which
never completely recovered.In MVA (overall p=0.0027), V40Gy (continuous
variable, p=0.025, OR=1.033), use of antihypertensives (protective factors,
p=0.028, OR=0.30) and presence of colon morbidity before RT (p=0.036,
OR=4.33) resulted to be correlated to mlinc.The figure shows mlinc as a function of V40Gy: a clear relationship can be seen between the dose bath at
V40Gy and mlinc.

Conclusions: The use of a longitudinal definition of linc is helpful in taking
both the duration and the severity of symptoms into account. The use of
mlinc: provides additional information which was not elucidated by analysing
linc as a peak tox (recording of the maximum grade of linc) and unveils astronger relationship between dosimetric factors (V40Gy) and clinical risk factors (presence of colon morbidity before RT and use of antihypertensives)
than previously found with linc defined as peak tox (Fellin 2009).
178 oral
LACK OF CORRELATION BETWEEN DVH SPECIFIC ENDPOINTSFOR OAR AND LATE TOXICITY FOR PROSTATE CANCER PATIENTSTREATED WITH IMRT
G. Crehange1 , E. Martin1 , C. Mirjolet1 , M. Gauthier2 , G. Truc1 , K.
Casasnovas1 , A. Petitfils3 , S. Naudy3 , F. Bonnetain2 , P. Maingon1
C ENTRE G EORGES -F RANÇOIS L ECLERC, Radiation Oncology, Dijon,
France2
C ENTRE G EORGES -F RANÇOIS L ECLERC, Biostatistics and Clinical Trials,
Dijon, France
3
C ENTRE G EORGES -F RANÇOIS L ECLERC, Radiation Oncology Physics,
Dijon, France

1

Purpose: The improvement of Dose-volume modeling of late toxicity inprostate cancer (PC) is of paramount concern in the context of high dose
IMRT. Dose volume specific endpoints (DVSE) have been demonstrated tobe reliable and reproducible for predicting toxicity with conformal 3D-RT. New
highly sophisticated delivery techniques can spare OAR more efficiently whilesubstantially increasing the delivered dose. We aim to evaluate whether or
not DVSE could predict accurately the occurrence of any late toxicity in thecontext of dose escalated IMRT.
Materials: Between august 2001 and December 2007, 170 men with localized PC were treated with exclusive IMRT with the same protocol. Whole
OARs were outlined on planning CT and a set of Dose-volume specific endpoints were systematically analyzed at treatment’s planning. Daily image
guidance was performed using a 3D US-based system. The median doseprescribed to the prostate was 78Gy (min. 74Gy max. 78Gy). Patients were
followed for evaluations after treatment every 6 months for 5 years and thenannually. Late toxicity was retrospectively scored according to the CTC v.3.0
morbidity grading scales. A Cox model was used to figure out any correlation
between DVSE and late toxicity.
Results: With a median follow-up of 38.3 months [5.25 87.3], rates of grade(G) 1, G2 genitourinary toxicity were 34.7%, 6.6%. The rates of grade G1,
G2 gastrointestinal toxicity were 20.4%, 2.4%. One patient had a genitourinary G3. For sexual potency, rates of G1, G2 and G3 were 25.8%, 29.3%
and 4.8%. No G4 toxicity was observed. For bladder, the average Dmean,
D98, V75 and V70 were 34.4Gy [6.6-72.0], 8.0Gy [0.2-70.0], 5.5Gy [0.0-64.9]
and 12.7Gy [0.0-74.1]. For the rectum, the average Dmean, D98, V75, V70
and V60 were 39.9 Gy [25.7-61.1], 8.9Gy [1.0-38.8], 1.1Gy [0.0-33.3], 6.0 Gy[0.0-44.0] and 19.0 Gy [1.0-70.0]. For the penile bulb, the average Dmean,
D98, V75 and V70 were 40.4Gy [3.0-77.0], 22.8 Gy [2.8-76.5], 9.4Gy [0.0100.0] and 18.3Gy [0.0-100.0]. Dmean and D98 were not predictive of any
G≥2 late toxicity for the bladder (OR= 1.06 [0.57-1.99], p= 0.84 and OR: 1.17
[0.63-2.20], p= 0.62); for the rectum (OR= 1.54 [0.82-2.89], p= 0.18 and OR=
1.34 [0.71-2.51], p= 0.37) and for the penile bulb (OR= 1.01 [0.44-2.32], p=

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0.98 and OR= 1.06[0.46-2.44], p= 0.89). Results from the Cox model for determining any correlation between DVSE and the occurrence of any ≥ G2
late toxicity are summarized in the following table:

regions and influences the volume effect.

Conclusions: A mechanistic model of normal-tissue damage is an effective
framework for summarising the radiobiological knowledgebase of radiation
pneumonitis, and plausible parameter values have been derived. Future predictive mechanistic modelling would require more quantitative histopathological studies on relevant local dose effects, thereby providing stronger evidence
for the local dose-response relationship. This would provide a stepping stone
from which the mechanisms of organ function loss, as a result of 3D distributions of FSU inactivation, could be studied separately.

Conclusions: Moderate escalated dose IMRT provides PC patients with very
low rates of any toxicity. As a result, commonly used DVH analyzes and DVSE
could be irrelevant with IMRT, thus jeopardizing the clinical benefit of dose escalation. More sophisticated tools evaluating the slope of the curve (terminal
part), AUC (Area Under the Curve) or EUD could predict more accurately late
toxicity when attempting to optimize dose distribution for doses above 78Gy.

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COMBINING DOSE-VOLUME INFORMATION AND PATIENT
CO-MORBIDITIES FOR PREDICTING RADIATION INDUCED PNEUMONITIS
A. L. Appelt1 , A. D. Nygaard1 , A. A. Khalil2 , I. R. Vogelius3 41

V EJLE H OSPITAL, Department of Oncology, Vejle, Denmark
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
3
R IGSHOSPITALET, Department of Radiation Oncology, Copenhagen,Denmark
4
U NIVERSITY OF C OPENHAGEN, Copenhagen, Denmark2

Purpose: The dose-limiting factor when treating lung cancer patients with curatively intended radiotherapy is often the risk of radiation induced pneumonitis (RP). In the present study, we investigated the influence of pre-existingco-morbidities on the risk of RP. Furthermore, we investigated whether theradiation dose-response fit to the clinical RP data could be improved by taking co-morbidities into account.
Materials: Data for 63 patients with inoperable lung cancer treated with curatively intended radiotherapy was retrospectively assessed. The treatment
plans were all conformal 3D plans; dose distributions were calculated witha collapsed cone algorithm and a mean equivalent lung dose in 2 Gy fractions (MELD) was obtained by correcting each dose bin for fractionation. Incidence of radiation pneumonitis was retrospectively graded following the CTCAE (v3.0) scale, as occurring within the first 6 months after the end of treatment. Any pre-existing severe co-morbidity for heart and lung was recorded
from assessment of patient records. Logistic regression was used to relate
MELD and co-morbidity as well as other clinical factors to the incidence ofgrade ≥ 2 RP.
Results: A simple, univariate logistic fit of the relationship between MELD
and RP was found using a response curve with D50 = 22.0 Gy (95% CI,
16.7-27.3 Gy) (dose resulting in 50% response) and steepness γ 50 = 1.18
(0.44-1.92). By including pre-existing co-morbidity in the regression in a multivariate fit, the model became significantly better (p = 0.023), see figure 1.
For the group of patients without co-morbidities, D50 = 26.2 Gy (17.0-35.4
Gy) and γ 50 = 1.44 (0.60-2.26); for patients with co-morbidities D50 = 18.8
Gy (5.5-32.1 Gy) and γ 50 = 1.04 (0.29-1.79). Thus the high and low risk
groups of patients were separated by an odds ratio of 5.07 (p = 0.034), witha difference in D50 of 7.35 Gy, and an increased steepness of the dose response curve for the patients without co-morbidities. The observed odds ratio
was larger than the simple odds ratio found when not taking dosimetric factors into account. Including other clinical risk factors (such as smoking status
and tumour histology) did not significantly improve the fit.

M ONDAY, M AY 9, 2011

Conclusions: The estimation of the dose-response for RP can be significantly improved when taking pre-existing coronary or pulmonary comorbidities into account. Patients with co-morbidities have a much lower
tolerated dose than patients without co-morbidities. It is advisable to takedosimetric factors into account when assessing odds ratios for potential clinical risk factors as the heterogeneity in the cohort originating from the variationin normal tissue dose may otherwise compromise the statistical power and influence the estimation of the odds ratio.
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EXPLORING THE BIOLOGICAL BASIS FOR THE MECHANISTIC
MODELLING OF RADIATION PNEUMONITIS
E. Rutkowska1 2 , I. Syndikus3 , C. Baker1 , A. E. Nahum1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics , Bebington, Merseyside, United Kingdom
2
R OYAL L IVERPOOL U NIVERSITY H OSPITAL, Medical Physics and ClinicalEngineering, Liverpool, United Kingdom
3
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Bebington, Merseyside, United
Kingdom
Purpose: In this study we explore whether a reductionist approach to modelling radiation pneumonitis (RP) can accommodate clinical and preclinicaldata on the pathogenesis of this dose-limiting complication. A previously developed mechanistic 3D model (Rutkowska et al., Phys. Med. Biol. 55 (2010)
2121-2136) is used as a framework for summarising current radiobiologicalknowledge and deriving plausible parameter values for the model.
Materials: The local dose-response function was deduced from data on thedensity of epithelial stem cells and their radiosensitivity, as well as the threshold dose for loss of local lung function. The relationship between radiosensitivity and stem cell density assumed in the model was used to identify thefunctional subunit (FSU). Further, volume effect mechanisms were exploredby studying the results of dose-volume analyses and animal studies.The levelof inter-patient variation in radiosensitivity was guided by experimental animal
data and adjusted to make the local dose-response function agree with thedoses tolerated during total lung irradiation. The value for inter-patient variation in health status was chosen based on the strength of correlation between
mean lung dose and published outcome.
Results: RP was modelled as resulting from extensive FSU inactivation. It
is likely that the target cell for local tissue damage is the type II endothelial
cell and that FSU inactivation increases over a range of 6-22 Gy (see figure).
This finding, together with considerations of the histology of the lung, supports the hypothesis that the alveolus is the FSU corresponding to RP.The
importance of low doses indicated by the figure might be exaggerated due tochemotherapy, but is supported by correlations between V5 and lung toxicity
found in recent studies. It is also consistent with the perception that the lungis very radiosensitive; a large volume effect is required to explain the muchhigher doses tolerated when given to small volumes. Inflammation, triggeredby radiation-induced tissue damage, spreads damage even to unirradiated

ESTIMATED LIFE YEARS LOST DUE TO FATAL LATE COMPLICATIONS AFTER PHOTON OR PROTON RADIOTHERAPY
P. Brodin1 , I. R. Vogelius2 , M. Maraldo2 , M. Aznar2 , A. K. Berthelsen3 , T.
Björk-Eriksson4 , P. Munck af Rosenschöld2 , P. Nilsson5 , L. Specht26 , S.
Bentzen72
1
C OPENHAGEN U NIVERSITY AND C OPENHAGEN U NIVERSITY H OSPITAL,
Department of Radiation Oncology, Copenhagen, Denmark
2
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of Radiation
Oncology, Copenhagen, Denmark
3
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of radiation
oncology and the department of nuclear medicine, Copenhagen, Denmark4
S KÅNE U NIVERSITY H OSPITAL, Department of Radiation Oncology, Lund,
Sweden5
S KÅNE U NIVERSITY H OSPITAL, Department of Radiation Physics, Lund,
Sweden6
C OPENHAGEN U NIVERSITY, Faculty of Health Sciences, Copenhagen,Denmark
7
U NIV. OF W ISCONSIN S CHOOL OF M EDICINE AND P UBLIC H, Departmentof Radiation Oncology, Madison WI, USA
Purpose: To estimate and compare the shortening of life expectancy (LE)due to radiation-induced secondary cancers (SC) and cardiac events after
photon or proton radiotherapy (RT). Estimating the Life Years Lost (LYL) for
competing causes of treatment-related mortality allows direct long-term risk
comparison between alternative radiotherapy plans or modalities.
Materials: The largest clinical data sets available are used to extract doseresponse (DR) parameters for the excess relative risk (ERR) for each endpoint. The ERR is combined with the age- and gender-specific incidence inthe general population (GP) to estimate the absolute excess risk (AER). The
excess mortality rate (EMR) is then estimated by including the prognosis foreach endpoint. The remaining LE for a person of a specific age in the GP
gives the LYL for a patient dying at that age. Competing risks of death prior
to a treatment-related event is taken into account from life tables of childhood cancer survivors. Integrating over all ages gives the LYL attributable toeach complication. The LYL measure is sensitive to the associated mortality
and age dependency of late complications, weighting early occurring events
higher due to more years lost at younger ages. We apply the LYL measure
for comparing treatment plans created with 3D conformal RT (3D CRT), arc
therapy (RapidArc® (RA)) and spot-scanned intensity-modulated proton therapy (IMPT) for craniospinal irradiation (CSI) of 10 paediatric patients.A paired
Monte Carlo method is used to test for difference in LYL between modalities.
The main source of uncertainty lies in the DR relationship for the different
endpoints. Samples are drawn from a log-transformed normal distribution
matching the confidence intervals (CI) of the DR parameters. For each sample, the difference in LYL between pairs of modalities was calculated and thecorresponding mean and CI for each patient was extracted from the distribution.
Results: Figure 1 shows the final LYL estimate averaged for all ten patients.
The attributable LYL varies among endpoints as a function of treatment technique. The dominating causes of LYL appear to be secondary lung cancer

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and cardiac events as a result of the poor prognosis after these events. In
the paired samples test the total LYL was significantly lower for RA than for
3DCRT, mainly due to substantially lower cardiac dose, and LYL with IMPT
was significantly lower than for both photon techniques.

Figure 1. Estimated LYL attributable to various endpoints for the 3D-CRT, RA
and IMPT techniques. LYL varies between treatment techniques due to differences in the distribution of non-target dose. The full bars represent the mean
total LYL for the ten patients for each of the three techniques. Statisticallysignificant p-values from the paired comparison of LYL between techniques
show that these differences are relatively insensitive to uncertainty in DR parameters.
Conclusions: The LYL measure provides a framework for direct comparisonof SC risks and risks of other adverse late complications and is readily applicable to other treatment techniques and endpoints provided the necessarymodel parameters are available. For the ten paediatric patients studied, we
found a significant difference in LYL favoring proton over photon radiotherapy.
We also found a difference favoring RA over 3DCRT, this ranking will however
depend strongly on the relative weight of SC and cardiac events.
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EORTC RADIOTHERAPY QUALITY ASSURANCE PLATFORM: ESTABLISHMENT OF AN INTEGRATED CENTRAL REVIEW FACILITY
A. Gulyban12 , P. Fenton23 , A. Fairchild2 , E. Aird4 , V. Grégoire5 , D.
Lacombe2 , O. Matzinger6 , P. Poortmans7 , B. Baumert8 , R. Pascal2 , D. C.
Weber9 , C. Hurkmans10
1
UZ-B RUSSEL, Brussel, Belgium
2
EORTC H EADQUARTERS, Brussels, Belgium
3
S OUTHAMPTON U NIVERSITY H OSPITAL NHS T RUST, Southampton, United
Kingdom
4
M OUNT V ERNON H OSPITAL, Northwood Middlesex, United Kingdom
5
UCL C LINIQUES U NIV. S T.L UC, Brussels, Belgium
6
C ENTRE H OSPITALIER U NIV. VAUDOIS, Lausanne, Switzerland
7
D R . B ERNARD V ERBEETEN I NSTITUUT, Tilburg, Netherlands
8
MAASTRO CLINIC, Maastricht, Netherlands
9
H ÔPITAL C ANTONAL U NIV. G ENÈVE, Geneva 14, Switzerland
10
C ATHARINA Z IEKENHUIS, Eindhoven, Netherlands
Purpose: Quality assurance (QA) in multi-centre clinical trials is essential toensure treatment is safely and effectively delivered. As QA requirements haveincreased in complexity in parallel with evolution of radiotherapy (RT) delivery
techniques, a pressing need to facilitate digital data exchange and timely review has emerged. Our objective is to present the platform developed for the
integration and standardization of QART activities within our pan-European
academic clinical trial organization.
Materials: Based on 30 years of RT clinical trial and QA experience, the central coordinating team and QART strategic committee identified the essential
requirements for the platform: secure and easy access to data without onsite hardware installation; integration within the coordinating centre’s existing
clinical remote data capture system; and the ability to both customize the platform to specific studies and adapt to currently unforeseen future needs. After
retrospective testing within several clinical trials, the platform was introducedin phases to participating sites and QART study reviewers.
Results: The resulting QA platform, integrating RT analysis software installedat the coordinating centre, permits timely, secure, and fully digital central
DICOM-RT based data review (Figure 1). Participating sites submit requested
data through a standard secure upload webpage. Supplemental information
is submitted in parallel through web-based forms such as type of treatment
planning system and description of the treatment verification protocol. An
internal quality check by the coordinating team verifies data consistency, formatting, completeness, and anonymization. Personnel responsible for QART
reviews have remote online access to DICOM-RT data through a terminal
server, and receive relevant clinical data as well. Reviewers evaluate submissions for protocol compliance through a standardized online evaluation

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matrix. Comments are collected by the coordinating centre after which participating institutions are informed of the results.

Conclusions: This integrated, web-based central review platform facilitates
the performance of rapid, extensive, and prospective QART patient review
within large multinational clinical trials. Timely central review completed inthis manner allows reduction of the risk that trial outcomes are compromised
through inadequate radiation delivery.

RTT Proffered Papers 2: Head and Neck Cancer
Treatment
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IS THERE A CORRELATION BETWEEN SMOKING AND LATE SIDE
EFFECTS FOR HEAD AND NECK CANCER PATIENTS?
D. Wiinholdt1 , C. Pisinger2 , B. Frederiksen2
1
C OPENHAGEN U NIVERSITY H OSPITAL, Department of Radiation Oncology,
Copenhagen, Denmark
2
G LOSTRUP H OSPITAL, Research Centre for Prevention and Health,
Glostrup, Denmark
Purpose: In 2006, 937 new cases of cancer in larynx, pharynx and cavum
oris were registered in Denmark. Because the disease has often spread tothe lymph nodes, the patient is normally treated with radiotherapy. The primary causes of these diseases are smoking and alcohol and, thus, mostpatients are smokers or newly quitters. Every head and neck cancer patient
treated with radiotherapy gets side effects. Currently, we do not know whether
smoking has an influence on the severity of these side effects, and this question is what we seek an answer to in this thesis.
Materials: 795 patients with head and neck cancer who are registered in
the Danish Head and Neck Cancer Group’s database and treated with radiotherapy in the period from 2000-2009 at Copenhagen University Hospital(Rigshospitalet), are included in the study. The patients are divided into 3
groups: never smokers, ex-smokers and smokers. In logistic regressions, wehave looked at smoking and its effect on the side effects 6 and 12 months
after end of treatment, respectively. The 6 types of side effects considered
are: voice, fibrosis, dryness, dysphagia, atrophy and edema.
Results: A significant correlation between smoking at baseline and the side
effects dysphagia and edema after 12 months have been observed. We also
found a significant correlation between the amount of smoking per day andthe number of moderate to severe side effects. Also, quitting smoking during
treatment results in a significant reduction in the probability for experiencing
the side effects voice and edema.
Conclusions: The results are based on, as far as we know, the biggest datamaterial on smoking and late side effects of radiotherapy. We can conclude
that smoking cessation before or during treatment will have a positive effecton the severity and amount of side effects.

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DYSPHAGIA REDUCTION WITH OPTIMIZED PHOTON AND PROTON INTENSITY-MODULATED RADIOTHERAPY FOR HEAD AND
NECK CANCER
H. P. van der Laan1 , T. van de Water1 , H. van Herpt1 , M. Christianen1 , H. P.
Bijl1 , C. Schilstra1 , H. Langendijk1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Department of Radiation Oncology, Groningen, Netherlands

QUALITY OF LIFE ASSESSMENT IN EARLY STAGES GLOTTISCANCER PATIENTS WHO ARE IN THE FOLLOW-UP PERIOD
J. I. Arraras1 , F. Arias1 , A. Manterola1 , M. Uzcanga2 , E. Maravi2 , M. Vila1 ,V. Chicata1 , C. Eito1 , G. Asin1 , U. Zarandona1 , E. Villafranca Iturre1 , M.
Dominguez Dominguez1
1
H OSPITAL DE N AVARRA, Department of Radiation Oncology, Pamplona,
Spain
2
H OSPITAL DE N AVARRA, Otolaryngology, Pamplona, Spain

Purpose: To compare the probability of dysphagia (swallowing dysfunction)with standard intensity modulated radiotherapy (st-IMRT), swallowing sparing
IMRT (sw-IMRT), standard scanned beam intensity-modulated proton therapy(st-IMPT) and swallowing sparing IMPT (sw-IMPT).
Materials: Five patients with oropharyngeal cancer were treated with bilateral irradiation on the primary tumor and the neck and were selected for thisplanning comparative study. For each patient, st-IMRT, sw-IMRT, st-IMPT and
sw-IMPT simultaneous integrated boost treatment plans were created. In 35
similar fractions, a total dose of 70 Gy was delivered to the boost planningtarget volume (PTV) and 54 Gy was delivered to the elective nodal PTV. The
st-IMRT and st-IMPT treatment plan optimization was performed to obtain adequate target volume coverage, limited dose in critical structures such as the
spinal cord and sparing of the parotid glands as much as possible. These
primary objectives were similar for sw-IMRT and sw-IMPT, except that specific attempts were made to spare the organs at risk related to swallowing
dysfunction (SWOARs, Table 1). For all plans, normal tissue complication
probabilities of physician-rated and patient-rated dysphagia were calculatedwith predictive models that were recently developed at our institute.
Results: All plans had adequate target volume coverage and the dose to critical organs was within accepted limits. The mean dose to the parotid glands
was similar for st-IMRT and sw-IMRT, and lowest with st-IMPT and sw-IMPT.
With sw-IMRT and sw-IMPT, the dose to the various SWOARs was reduced
when compared to st-IMRT and st-IMPT, respectively. In general, the lowest
dose to the SWOARs was obtained with sw-IMPT. The predicted mean probability of grade 2-4 physician rated dysphagia (RTOG) was 47%, 36%, 45%
and 31% with st-IMRT, sw-IMRT, st-IMPT and sw-IMPT, respectively. Patient
rated moderate to severe complaints with regard to the swallowing of solid
food, soft food, liquid food and aspiration with sw-IMRT and sw-IMPT weresimilar (Table 1).
Conclusions: The predicted probability of different dysphagia-related endpoints with IMRT and IMPT was reduced by limiting the dose in the SWOARs.
The lowest probability of dysphagia was predicted with sw-IMPT.

Purpose: The aims of the present study are to assess quality of life in a sample of glottis cancer patients who are in the treatment follow-up period, and to
study the differences in Quality of Life between two treatment modalities.
Materials: A sample of patients with early larynx carcinoma glottis in initial stages (T1, T2 N0) has been included in the study. Patients were in thefollow-up period of at least one year.Patients had received either radiotherapy or conservative surgery. Those in each treatment modality had received
the same protocol.Quality of Life has also been assessed in the follow-up period through the EORTC questionnaires QLQ-C30 and QLQ-H&N35, and the
Voice Handicap Index (10 items version).
Results: 100 patients have performed the Quality of Life assessment. 59
had received radiotherapy, 32 surgery and 9 combined treatment.Quality ofLife scores in the QLQ-C30 with the whole sample showed light limitations(15 18 points / 100) in five areas. Light alterations in the QLQ-H&N35 havebeen found in one area (15 20 /100); moderate (20-30/100) in five areas;
and between 30 40 in dry mouth and weight gain. Mean score in the Voice
Handicap Index was 9.3 / 40.No significant differences between treatments
have been found in variables that could influence quality of life: limiting comorbidity, Karnofsky y number of relapses.Differences have been found inemotional functioning (88.5 76.6) and social contact (4.6 12.1) in the EORTC
questionnaires, and in the Voice Handicap Index (6.1 12.8) that favour theradiotherapy group.
Conclusions: Quality of Life scores in the sample are adequate. Weight gain
could be considered as a positive. Quality of Life is better in the radiotherapy
group.
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ASSESSMENT OF HEAD AND NECK IMMOBILIZATION DEVICEFOR ACCURATE RAPIDARC® TREATMENT DELIVERY
B. Al Ahmed1 , E. Khawandanah1 , N. Al Safadi1 , S. Al-Ghamdi1 , A. Saoudi1
1
K ING A BDULLAH I NTERNATIONAL M EDICAL R ESEARCH C ENTER(KAIMRC), Princess Noorah Oncology Center (PNOC), Jeddah, Saudi
ArabiaPurpose: Accurate patient immobilization has become more important withhighly conformal radiotherapy techniques such as RapidArc® that use a steep
dose gradient between tumour and organs at risk. This study was performed
to evaluate the improvement in set-up accuracy in head and neck cases resulting from the introduction of a customized headrest and a precise mouth
bite to the current five fixation points posicast-plus thermoplastic mask.
Materials: The study was performed retrospectively on 58 head and neckcancer patients. The first group of 39 patients were immobilized with five fixation points posicast-plus thermoplastic mask using a standard posifix supine
headrest. The second group of 19 patients were immobilized using thesame system complemented with customized accuform cushion and a precise mouth bite that is attached to the thermoplastic mask. All patients had
a planning CT scan with 2 mm slice thickness and pixel size of 1.27mm x
1.27mm. Our IGRT protocol uses a Cone Beam CT (CBCT) scan with 2.5mm slice thickness and pixel size of 0.65mm x 0.65mm. Data were collectedusing Off Line Review, ARIA® application. The isocenter shifts were calculated from co-registration of CBCT’s and planning CT in three translational
directions (Anterior-Posterior (AP), Superior-Inferior (SI) and Right-Left (RL)).
The 3D anatomical match was approved by the radiation oncologist. In thisstudy the rotational shifts were not taken in account.
Results: A total of 283 CBCT’s were analyzed, of which 125 were obtained
from the first group of patients and 158 from the second group. Translational
shifts more than 2mm were applied to 28% (AP), 22.4% (SI) and 13.6% (RL)of the total population of the first group. Our study of this group suggeststhat the standard posifix headrest doesn’t prevent head rotation both in the
SI and RL direction, resulting from the daily variation in the neck curvature.
This lead us to enforce the immobilization system by adding a mouth biteto minimize the RL and SI shifts and by adding a customized head rest to
stabilize the neck curvature as well as reducing the SI and AP shifts. The
results improved considerably in the second group. Translational shifts morethan 2mm were applied to only 0.6% (AP), 2.5% (SI) and 1.9% (RL) of thetotal population of the second group of patient.
Conclusions: Our result shows that adding a customized headrest cushion and a mouth bite to the five fixation points posicast mask reduces considerably the daily shifts. Sufficient set-up accuracy in all translation directions (Mean ± SD) (AP (0±1.02mm), SI (0±1.3mm), RL (0±1.19mm)) was
achieved for the RapidArc® treatment delivery where PTV margin is 3mm.
As a result the IGRT protocol was changed from a weekly CBCT followed

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by daily kV-kV imaging to three consecutive CBCT at the start of treatment
followed by weekly CBCT throughout the treatment period.
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DOSIMETRIC EVALUATION OF A THREE-PHASE ADAPTIVE RADIOTHERAPY FOR NASOPHARYNGEAL CANCER USING HELICALTOMOTHERAPY
W. W. K. Fung1 , W. C. V. Wu2
1

H ONG KONG S ANATORIUM & H OSPITAL, Department of Radiotherapy,
Happy Valley, Hong Kong (SAR) China
H ONG KONG P OLYTECHNIC U NIVERSITY, Department of Health Technology and Informatics, Kowloon, Hong Kong, SAR, China
2

Purpose: Adaptive radiotherapy (ART) has been introduced in head andneck case to restore the planned dose distribution by correcting the radiationinduced anatomic changes during a treatment course. Nevertheless, few
studies have been carried out specifically on nasopharyngeal carcinoma(NPC), and the issue of when and how often the ART should be performed
is still controversial. This study evaluated the potential dosimetric benefits ofapplying a three-phase adaptive radiotherapy protocol in NPC patients compared to the non-adaptive single phase treatment protocol.
Materials: Ten NPC patients previously treated with this three-phase radiation protocol using Hi-Art Tomotherapy were included. Two new plans, denoted as PII-ART and PIII-ART, were generated based on the up-to-date CT
images and contours and were used for treatment in phase two (PII; after 25th
fraction) and phase three (PIII; after 35th fraction) respectively. To simulate
the situation of no replanning, two hybrid plans denoted as PII-NART and
PIII-NART were generated using the original contours pasted on the PII- andPIII-CT sets by CT-CT fusion. Dosimetric comparisons were made between
the NART plans and the corresponding ART plans.
Results: In both PII- and PIII-NART plans, the doses to 95 % of all the target
volumes (D95) were increased with better dose uniformity, while the organs
at risk (OARs) received higher doses compared to the corresponding ART
plans. Without replanning, the total dose to 1 % of brainstem and spinal cord(D1) significantly increased 7.87±7.26 % and 10.69±6.72 % respectively(p = 0.011 and 0.001 respectively), in which 3 patients would have thesestructures overdosed when compared to those with twice replannings. The
total maximum doses to the optic chiasm and pituitary gland and the meandoses to the left and right parotid glandswere increased by 10.50±10.51 %,8.59±6.10 %, 3.03±4.48 % and 2.24±3.11 % respectively (p = 0.014, 0.003,
0.053 and 0.046 respectively).
Conclusions: The three-phase radiotherapy protocol showed improved dosimetric results to the critical structures while keeping satisfactory target dosecoverage, which demonstrated the advantages of ART in helical tomotherapyof NPC. Moreover, the ART protocol involving two replannings as in this study
was deemed necessary to account for the anatomic variation in later fractionsof radiotherapy for NPC patients.
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DOSE PAINTING BY NUMBERS FOR HEAD AND NECK CANCER:
18F-FDG-PET-VOXEL INTENSITY-BASED VMAT VERSUS 18F-FDGPET-VOXEL INTENSITY-BASED IMRT
B. Speleers1 , I. Madani1 , W. De Gersem1 , W. De Neve1
1
U NIVERSITAIR Z IEKENHUIS, Department of Radiotherapy, Gent, Belgium
Purpose: to compare 18 F-FDG-PET-voxel intensity-based VMAT and IMRT
in dose painting by numbers (DPBN) for head and neck cancer.
Materials: 18 F-FDG-PET-voxel intensity-based VMAT plans were created for
10 non-metastatic head and neck cancer patients treated by 18 F-FDG-PETvoxel intensity-based IMRT in a phase I clinical trial on adaptive DPBN [1].
Dual arc VMAT plans with control points between -176 to -48 and 48 to 176
degrees were optimized with in-house developed extension of the GRATIS
software package [2]. Each patient had two DPBN plans followed by conventional (homogenous dose) treatment. The initial DPBN plan was based ona pre-treatment PET/CT scan while the second DPBN plan (fractions 11-20)
was based on a PET/CT scan acquired after the 8th fraction. The median prescription dose to the dose-painted volume was 30 Gy for both DPBN plans.
The median dose prescription for the conventional plans (fraction 21-32) was
26 Gy. Biological conformity of the plans was evaluated with Q-factor (QF)
[3].
Results: VMAT provided consistently higher biological conformality than
IMRT: QF was 1.6±0.6% vs. 3.4±0.9% (p=0.001) for DPBN1; 1.3±1.1%
vs. 3.5±0.4% (p<0.001) for DPBN2, respectively. Dose-volume parameters
were either equal for IMRT and VMAT, or were better for VMAT (Table 1). D50
to the spinal cord was significantly less in all VMAT plans (p=0.008 for the 1st
and 0.004 for the 2nd DPBN plan). Parotid glands were spared better in VMAT
plans based on pretreatment images: p=0.04 and 0.02 for the right and leftparotid, respectively. D2 and D50 in the high-dose clinical target volume andD2 in the joined (high-dose and elective neck) planning target volume wassignificantly higher in all VMAT plans as compared to IMRT plans.

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T UESDAY, M AY 10, 2011

Tuesday, May 10, 2011

Symposium

Teaching lecture

30 years of radiation oncology in Lung cancerWhat is the evidence that ‘we’ have created? - Update on randomized trials and Meta-analyses

190 speaker
PUBLICATIONS OF BRACHYTHERAPY ARTICLES: OVERVIEWAND CURRENT TRENDS WITH FOCUS ON “RADIOTHERAPY AND
ONCOLOGY”
R. Pötter1
1
M EDICAL U NIVERSITY V IENNA , AKH, Radiation Oncology, Vienna, Austria

Conclusions: Conclusion: VMAT ensures better higher biological conformity of DPBN plans than IMRT. It spares better organs at risk such as the
spinal cord and parotid glands. References 1. Duprez F, De Neve W, De
Gersem W, et al. Adaptive Dose Painting by Numbers for Head-and-Neck
Cancer. Int J Radiat Oncol Biol Phys 2010 Jul 17. [Epub ahead of print].2.
Sherouse G W, Thorn J, Novins K, et al. A portable 3D radiotherapy design system. Med Phys 1989;16:466.3. Vanderstraeten B, Duthoy W, De
Gersem W, et al. [18F]fluoro-deoxy-glucose positron emission tomography([18F]FDG-PET) voxel intensity-based intensity-modulated radiation therapy(IMRT) for head and neck cancer. Radiother Oncol 2006;79:249-58.
189 oral
DOSIMETRIC AND RADIOBIOLOGIC EVALUATION OF BIOLOGICALLY ADAPTED IMRTJ. Rødal1
1
T HE N ORWEGIAN R ADIUM H OSPITAL, Department of Medical Physics,
Oslo, Norway
Purpose: The purpose of the study was to evaluate the planning and deliveryof highly heterogeneous, biologically adapted intensity modulated radiotherapy (IMRT) by dosimetric and radiobiologic measures.
Materials: A 3D hypoxia map of a highly heterogeneous tumour was imported
into the CT planning basis of an anthropomorphic phantom head. EDR2
films were inserted in two transversal planes of the phantom head. The tumour was segmented into four compartments based on the oxygen levels.
The compartments appeared non contiguous, with multiple, millimetre sizedfoci. Biologically adapted IMRT was planned according to the corresponding
3D dose prescription map. Three treatment fractions were delivered to thephantom by means of a conventional linear accelerator equipped with a highresolution micro multi leaf collimator (MLC). Software was developed for voxel
wise analyses of the dose distributions from the prescription, dose plan andfilms. Dose distributions were scored within the four radiobiological tumour
compartments and the treatment effect in each compartment was estimatedas the equivalent uniform dose (EUD). A conventional gamma analysis was
performed for quantitative comparisons of planned and delivered dose distributions.
Results: The dose delivery was conformal to the planned dose distribution.
The gamma analyses showed that, on average, more than 95% of the film
pixels within the tumour passed the 3%/2 mm criteria.The EUD values for thedose plan were severely reduced compared to the prescription (difference
range +1.2% to -33.5%). The differences increased with increasing degreeof hypoxia. The prescribed compartmental doses were met only for the mostoxic compartment.The mean tumour doses measured by the films were lower
than the dose plan values and lay in mean 6.6% ± 0.6% (1 SD) lower than theplanned values. The compartmental EUD values were reduced accordingly(range 3.6% to 11.3%).
Conclusions: Heterogeneous, biologically adapted radiotherapy may be delivered with high precision compared to the dose plan. The compartmental
EUD values showed large reductions from prescribed to delivered treatment,
however, indicating a lower tumour effect than expected. The largest drop in
EUD values occurred in the inverse planning, suggesting inadequate planningand treatment technique.

T UESDAY, M AY 10, 2011

Brachytherapy is among the first techniques pioneered for clinical deliveryof radiation more than 100 years ago with also a long publication history.
Brachytherapy has reached a key role in various clinical fields, among themost outstanding have been gynaecology, urology (prostate), head and neck,eye, and recently also increasingly breast.
The introduction of new radioactive sources with challenging physical and biological characteristics and then remote afterloading techniques prompted alarge popularity of brachytherapy, starting in the 60 with outstanding developments by major brachytherapy schools in Europe (e.g. Paris) and abroad (e.g.
MSKCC) strengthening the role of brachytherapy in the traditional fields suchas gynaecology, head and neck, urology, and breast. This was followed by
the introduction of new dose rates MDR/HDR/PDR, which resulted in major
developments, with HDR and PDR replacing nowadays completely the traditional LDR and MDR.
The following factors and absolute numbers are based on Pubmed search
introducing "brachytherapy" and a second specific keyword.
In the 80’ US guided brachytherapy for prostate cancer was developed andthen clinically implemented resulting in a large and continuous increase of
related publications from 1990 to 2000 by a factor of 17, from 2000 to 2010
by 1.4.
The introduction of CT and MRI into treatment planning lead to a significant
increase of publications from 1990/2000/2010 by 2.9/1.6 for CT and 6.0/2.2
for MRI.
Different subfields of brachytherapy show different trends according to recent
developments. Comparing the years 2000 to 2010, the increase was for gynaecology 1.9, for prostate 1.4, for breast 6.5; the decrease was for endovascular 0.3, while a stable rate of publications was found for head and neck andsarcoma .
For medical physics there has been a significant increase 2000-1010 with afactor of 2.5 from mean ~28 to mean ~69 per year. For radiobiology there isa rather stable situation with an overall low absolute number of 5-10 publications per year.
Brachytherapy related publications show overall during the last three decades
a significantly increasing trend representing the actual issues of development and research during the respective periods as listed above. Using"brachytherapy"as keyword Pubmed lists 148 articles in 1980, 384 in 1990
(2.6), 685 in 2000 (1.8) and 895 in 2010 (1.3) with an overall increase of 6.1
from 1980 to 2010.
During this 30 year-period significant developments not only took place in thevarious areas of research and development but also related to the methods ofscientific publications. These changes have been mostly pronounced in theclinical (and translational) field. The instrument of the "clinical trial" has been
elaborated (phase I-III), with a broad spectrum of clinical research methodologies nowadays available and applied, also for radiotherapy. Whereas in
the past clinical evidence had been mainly derived from single center experience following a certain protocol, this has been steadily replaced during thelast decades by prospective hypothesis driven (multicenter) trials with a welldesigned prospective assessment of endpoints throughout the trial period.
Accordingly, different levels of clinical evidence have been suggested (levels1-5) which form the basis for clinical guidelines becoming increasingly important for the standard practice in oncology.
The pattern of brachytherapy publications only partly reflects the generaltrend towards an increase of prospective trials. Comparing numbers by
Pubmed research there are only few prospective trials during the whole period 2000 to 2010, with a mean value of 7-11 phase II trials per year for thevarious large fields of clinical brachytherapy and altogether 17 brachytherapy
related phase III trials from 2000-2010. This trend is in accordance with the
publication pattern in the green journal during the last years 2007-2010. The
majority of published clinical brachytherapy papers (31) was based on retrospective evaluation of clinical series (28), whereas there were only 3 prospective clinical trials and 2 of them phase III. From the submitted manuscripts on
clinical studies the majority had to be rejected mainly due to the limitationsin clinical study design, with an overall rejection rate of 76% (96/127). This
trend will even increase according to the green journal guidelines comparable
to any peer reviewed journals in regard to clinical studies.
Another increasingly large category of publications may be called "translational" in regard to treatment planning and imaging, which is usually in limited
patient (material) cohorts which are partly related to outcome (prostate, gynaecology).
It seems therefore urgent for the whole brachytherapy field to increase thenumber of prospective trials (including also "translational" research) to provide high level clinical evidence in the various areas of brachytherapy.

191 speaker
THE CONTROVERSY OF MODIFIED FRACTIONATION REGIMENS.
M. I. Saunders12
1
M OUNT V ERNON H OSPITAL, Oncology, Northwood Middlesex, United
Kingdom
2
U NIVERSITY C OLLEGE L ONDON, London, United Kingdom
Saunders M I - Emeritus Professor of Oncology University College London
and Mount Vernon Hospital Middlesex in collaboration with the Meta-Analysisof Radiotherapy in Lung Cancer (MAR-LC) Collaborative Group.
Lung cancer remains the commonest cause of death from cancer in Europe
with 334,800 deaths (20% of all cancer deaths) occurring in 2006. 80% of
these tumours are non small cell lung cancer (NSCLC) and 20% small cell
carcinomas (SCLC). Radiotherapy plays an important role in the cure andpalliation of all histological types but more so in NSCLC which, unlike SCLC,
is of limited responsiveness to chemotherapy.
Modified fractionation schedules were planned to improve the outcome of radiotherapy by reducing the overall time of treatment to prevent repopulation(acceleration) and lowering the dose per fraction to decrease late morbidity(hyperfractionation).
Many modified fractionation regimens were studied from the very accelerated
eg CHART where 54 Gy was given in 36 fractions of 1.5Gy tds over 12 days
inclusive of the week-ends to hyperfractionated regimens which gave 69.6 Gy
in 1.2 Gy fractions bd over 47 days.
An individual patient data meta-analysis has been performed in patients with
non-metastatic lung cancer investigating the effect of modified fractionation
on overall survival (OS), progression free survival (PFS), acute and late morbidity. Preliminary results have been reported on behalf of the Meta-Analysisof Radiotherapy in Lung Cancer (MAR-LC) Collaborative Group. An updatewill be presented at this meeting.
Ten trials have so far been included 8 involving patients with NSCLC and 2 in
SCLC. These trials compared modified radiotherapy (accelerated, hyperfractionated or both) to conventional radiotherapy (1.8 to 2Gy per day five days ofa week to a minimum of 60Gy for NSCLC and 40Gy for SCLC).
The 8 NSCLC trials so far analysed randomised a total of 1,594 patients
who were divided into four groups very accelerated radiotherapy, moderately
accelerated radiotherapy, hyperfractionated radiotherapy with identical dose,
hyperfractionated radiotherapy with increased dose. CHART contributed 35%
of all the patients and as this showed a highly significant improvement in survival it played an important role in the outcome of the meta-analysis.
Modified fractionation improved overall survival (OS) as compared to conventional RT (hazards ratio HR=0.87, 95% confidence interval [0.79-0.97],
p=0.009), resulting in an absolute benefit of 3% at 5 years. This benefit was
not seen on PFS (HR=0.94 [0.85-1.04], p=0.23).No heterogeneity between
trials was found and no subgroup of patients benefited more or less frommodified RT.
Modified fractionation increased the risk of acute oesophageal toxicity(OR=2.13; p<0,001) but not the risk of acute pulmonary or cardiac toxicity.
There was no difference in late cardiac, esophageal or pulmonary toxicity but
the low incidence of events means more data is required before final conclusions can be drawn.
Radiotherapy is given to the mediastinum in SCLC to consolidate the response to chemotherapy. Only 2 trials were identified : OS improvement
was similar to that observed in NSCLC (HR 0.87 (0.74-1.02) with a borderline
signifigance p=0.08). The absolute benefit was1.7% at 3 years.
Modified fractionation in SCLC increased the risk of acute oesophageal toxicity (OR=2.41; p<0,001) and cardiac toxicity (OR 0.87; p=0.001) but not therisk of acute haematological or pulmonary toxicity. Late toxicity data is notavailable.
Considering palliation a series of randomised controlled trials in NSCLC conducted by the Medical Research Council in the 1980s demonstrated that 1 or
2 fractions of radiotherapy was as successful in palliation of symptoms due toboth the primary tumour and metastases as longer fractionation schedules.
This led to short fractionation techniques being applied to patients with advanced and metastatic lung cancer.
Has the benefit achieved justified all the effort? A rise in five year OS for
NSCLC from 9 to 11% may be regarded as marginal but it is a 31% improvement. Such active research has also been a great stimulus to the care ofpatients with lung cancer and the maintenance of high technical standards.
The introduction of FDG PET scans to exclude those patients with metastatic
disease and aid delineation of active disease together with highly conformal
radiotherapy may, with more effective chemotherapy, improve results in the
future.

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192 speaker
UPDATE ON RANDOMIZED TRIALS AND META-ANALYSESCONCERNINGINDUCTION
VERSUS
CONCOMITANT
RADIOCHEMOTHERAPY IN LUNG CANCER
1
1
2
1
C. Le Pechoux , A. Auperin , A. Mauguen , J. P. Pignon
1
I NSTITUT G USTAVE R OUSSY, Radiation Oncology, Villejuif, France
2
I NSTITUT DE C ANCÉROLOGIE G USTAVE R OUSSY, Radiation Oncology,
Villejuif, France
Lung cancer remains a major cause of death worldwide with more than 1.1
million deaths per year. Nonsmall-cell lung cancer (NSCLC) represents now
more than 80% of all lung tumors, and approximately 35% of patients with
NSCLC present with locally advanced nonmetastatic disease for who thestandard treatment has become combined radiochemotherapy. Small-celllung cancer represents 15-20% of all lung cancers, and less than a third ofthese patients who have no metastases will be eligible for combined chemoradiation.
Concerning locally advanced NSCLC, two meta-analyses based on individual
patient data have compared chemotherapy plus radiotherapy to radiotherapy
alone. These meta-analyses were recently updated and demonstrated thatsequential or concomitant chemoradiation improved survival compared to radiotherapy alone with an absolute modest benefit of 4% at 2 years and 2%
at 5 years [NSCLC Collaborative group,1995; Auperin, 2006; Le PechouxGeneve 2008)]. In 1990’s and 2000’s several randomized trials have compared sequential to concomitant chemoradiation. A meta-analysis of thesetrials was performed using individual patient data. [Auperin, 2010]. Data fromsix trials could be collected (1,205 patients, 92% of all randomly assigned
patients). Median follow-up was 6 years. A significant benefit of concomitant chemoradiation on overall survival (HR, 0.84; P=0.004) was observed,
with an absolute benefit of 4.5% (from 10.6% to 15.1%) at 5 years. As
compared to sequential chemotherapy, concomitant treatment decreased locoregional progression but had no significant differential effect on distant progression. As expected, concomitant radiochemotherapy increased grade 3-4
acute esophageal toxicity from 4% to 18% with a relative risk of 4.9 (p=0.001).
As in other solid tumors, concomitant radiochemotherapy should now be considered as the standard treatment in locally advanced NSCLC. However itshould be outlined that most of these trials used 2-D radiotherapy. Future trials should integrate the recent developments in three-dimensional conformal
radiotherapy to optimize concomitant combinations.
Concerning small cell lung cancer, one randomized trial has directly compared concomitant (?) to sequential chemoradiation, and two meta-analyses
have explored the optimal timing, comparing early TRT (Thoracic RadioTherapy) to late TRT and most of these trials included concomitant CTRT in theearly arm. In the only phase III trial, directly comparing concomitant to sequential TRT, the 2- and 5-year survival rates for patients who received sequential TRT were 35.1%, and 18.3%, respectively, as opposed to 54.4% and23.7%, for the patients who had concurrent radiotherapy (p=0.097) [Takada
2002]. Thus overall survival in the concurrent arm tended to be superior but
not significantly. Two meta-analyses based on published data, have investigated timing in SCLC combined modality treatments. They have demonstrated that a short time between the initiation of chemotherapy and the initiation of radiotherapy is prognostic for survival. The delay chosen to define
early and late treatment differs in these 2 studies: 9 weeks after initiation ofchemotherapy [Fried 2004] and 30 days in the other meta-analysis [De Ruysscher 2006]. In another study, De Ruysscher et al hypothesized that the duration from the start of any treatment until the end of radiotherapy (SER) was
important to consider [De Ruysscher 2006]. Concomitant chemoradiation allows a shorter SER as opposed to sequential regimen. Overall duration ofradiotherapy should be considered as well as timing of chest radiation. They
concluded that a short time between the initiation of chemotherapy and thesubsequent completion of radiotherapy was prognostic for survival. This SER
concept should certainly be further evaluated and considered in designing
new studies. Thus these meta-analyses, based on published data, suggestthat TRT should begin early, and accelerated regimen should be considered.
However these results are not very robust, and an ongoing meta-analysis
based on individual patient data, should help solving these important issues.
Its preliminary results showed that chemotherapy compliance is an importantfactor to consider.
Further studies are needed in lung cancer to optimize concomitant combinationsAcknowledgement:
Supported by unrestricted grants from French Programme Hospitalier deRecherche Clinique, Ligue Nationale Contre le Cancer, and Sanofi-Aventis

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T UESDAY, M AY 10, 2011
194 speaker

30 years of radiation oncology in Breast cancer What is the evidence that ‘we’ have created? - Update on randomized trials and Meta-analyses

RADIATION-RELATED HEART DISEASE FOLLOWING TREATMENT
FOR BREAST CANCER
C. Taylor1
1

U NIVERSITY OF OXFORD, Clinical Trial Service Unit, Oxford, United
Kingdom

193 speaker
RADIOTHERAPY AFTER BREAST-CONSERVING SURGERY IN
EARLY BREAST CANCER: UPDATE FROM THE EARLY BREASTCANCER TRIALISTS’ COLLABORATIVE GROUP
S. Darby1
1
U NIVERSITY OF OXFORD, Clinical Trial Service Unit, Oxford, United
Kingdom

Background: For common diseases, including breast cancer, treatmentsthat improve survival by only a few percentage points can save many lives.
Individual trials are often not large enough to detect such small differences
reliably, so overviews combining data from all trials are necessary. By doing
this, it is possible to obtain estimates of the differences between treatmentsthat are more precise than the estimates given by any individual trial. This
combination cannot be done satisfactorily from published data alone, as theinclusion of unpublished as well as published data is necessary to avoid bias.
Furthermore, the information available from the published trials is not sufficient to allow a uniform analysis of all the available data with appropriate
stratification for factors that will affect survival such as age, time since diagnosis, node status, and so on. Thus, analysis based on individual patient datais necessary.
Following breast-conserving surgery for early breast cancer, it is known thatradiotherapy can reduce the risk of recurrence and of death from breast cancer. The question arises as to whether the absolute benefit is greater for somegroups of women than for others. To examine the evidence for any such differences and, where appropriate, to quantify them, collaborative meta-analyses
of individual patient data have been undertaken of the relevant randomised
trials that began before 1 January 2000.
Material and methods: Information was available on 10,801 women in 17
randomised trials of radiotherapy after breast-conserving surgery. Medianfollow-up for early trials was 12.2 years, but only 6.6 years for recent trials
of women judged to be at low risk of recurrence. The 10-yr risks of any
recurrence (ie locoregional or distant) with and without radiotherapy were estimated for women with differing values of various predictive factors. 15-yr
risks of death from breast cancer and from all causes were also estimated.
Women were classified as large, medium, or small predicted absolute benefit
by considering the dependence of the rate of first recurrence on predictive
factors.
Findings: For all women (n=10,801), radiotherapy reduced the absolute 10year risk of any first recurrence by 15.7% (19.3% vs. 35.0%; 2p<0.00001) andthe absolute 15-year risk of breast cancer death by 3.8% (21.4% vs. 25.2%;
2p=0.00005).
In pN0 disease (n=7287), radiotherapy reduced the absolute 10-year risk ofany first recurrence by 15.4% (15.6 vs. 31.0%; 2p<0.00001), and the absolute
15-year risk of breast cancer death by 3.3% (17.2% vs. 20.5%; 2p<0.005).
For women with large, medium, and small predicted absolute benefit, 10-year
absolute reductions in first recurrence risk were 24.3 % (95% confidence interval 19.6, 29.0), 12.4% (9.7, 15.1) and 6.0% (2.2, 11.6) (2p trend <0.00001)
and 15-year absolute reductions in breast cancer death were 7.9% (95% confidence interval 3.1, 12.5), 1.0% (-2.0, 4.2), and 0.1% (-7.5, 7.7) (2p trend 0.03).
In pN+ disease (n=1050), radiotherapy reduced the absolute 10-year risk ofany first recurrence by 21.2% (42.5% vs. 63.7%; 2p<0.00001), and the absolute 15-year risk of breast cancer death by 8.5% (42.8% vs. 51.3%; 2p=0.01).
No factor was independently predictive of absolute benefit.
Interpretation: Radiotherapy conferred substantial absolute reductions in
the risks of recurrence and breast cancer death for pN+ women and for somegroups of pN0 women. For other pN0 women, radiotherapy conferred a moderate absolute reduction in recurrence risk and may also confer a small reduction in breast cancer death.

It has been recognized since the 1960s that the heart may be damaged bysubstantial doses of radiation [>30 Gray (Gy)], such as used to occur during mantle radiotherapy for Hodgkin lymphoma. During the last few years,
however, evidence that radiation-induced heart disease can occur following
doses below 20 Gy has emerged from several independent sources. Thesesources include randomized trials of radiotherapy in breast cancer patients
who received cardiac doses up to about 20 Gy and studies of survivors of theatomic bombings of Japan who received uniform whole-body doses of up to
4 Gy.
Much of our knowledge of the effect of radiation on the heart has come fromlong-term follow-up of breast cancer patients entered into trials in which all
women received similar treatment in terms of surgery and drugs, and thenhalf of the women were allocated at random also to receive adjuvant radiotherapy. One of the first studies to examine the effect of radiotherapy on
long-term survival in breast cancer was a meta-analysis of randomized trials
published in 1987 which showed that survival beyond 10 years was significantly worse for those receiving radiotherapy. This early study was unable
to determine the disease responsible for the detrimental effect on survival,
but subsequent meta-analyses by the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) have shown that mortality from heart disease wasincreased by 27% (2p =0.0001) in women randomized to surgery plus radiotherapy compared with women randomized to surgery alone. Most of theincrease was due to coronary artery disease.
Recently, a preliminary analysis of updated EBCTCG data has related mortality from heart disease to estimated cardiac doses in over 30,000 womenfollowed for up to 20 years. There is clear evidence that the radiation-related
increase is higher in trials with larger mean cardiac doses and that the riskof death from heart disease increases by 3% per Gy (95% CI, 2%-5%; 2p< 0.00001). This estimate can only be taken as an approximate indicationof the risk, as individual treatment plans were not available for the women in
those trials. Nevertheless, the data provide strong evidence that the risk ofradiation-related heart disease was related to cardiac dose in these irradiatedbreast cancer patients.
Outside the context of a randomized trial, comparisons of heart disease rates
in individuals exposed to radiation at different levels are often misleading because those exposed at different levels may well have had different levels ofrisk in the absence of any radiation exposure. In breast cancer, however, a reliable indication of the effect of radiotherapy on heart disease can be obtainedby comparing the experience of irradiated women with left-sided tumors withthat of women with right-sided tumors. This can be done because cardiac
radiation doses in women given radiotherapy for left-sided tumors are usuallylarger than the cardiac radiation doses in women with right-sided tumors, andbreast cancer laterality has, in the past, played little part in determining whoshould be given radiotherapy.
The opportunity afforded by the comparison of left-sided and right-sided
breast cancer patients paves the way for more detailed studies of the effectsof cardiac radiation on subsequent heart disease. For example, a recent
study examining the incidence of coronary artery disease following breast
irradiation revealed a higher prevalence of stress test abnormalities in leftsided than in right-sided tumor patients (59% vs. 8%; p = 0.001). Amongleft-sided tumor patients, the disease distribution differed from that expectedin women, with a preponderance of left anterior descending artery disease.
The anterior portion of the heart and the left anterior descending artery territory are the parts of the heart most often within the tangential radiation fields
used to treat breast cancer. Hence, this finding provides direct evidence ofa causal effect of radiotherapy on the development of coronary artery disease. Another example is the RACE study in which the remarkable possibilities available in Denmark and Sweden are being used to identify women withbreast cancer through the national cancer registries, and then to obtain details of their radiotherapy exposure from the national health care systems andalso information on any subsequent cardio-vascular events from the cause ofdeath and hospital discharge registries. Provisional results of this study will
be presented.

T UESDAY, M AY 10, 2011

Teaching lecture
195 speaker
VOLUMETRIC IMAGING: ADAPTIVE RADIOTHERAPY STRATEGIESFOR CLINICAL IMPLEMENTATION
V. Khoo1
1
R OYAL M ARSDEN H OSPITAL T RUST & I NSTITUTE OF C ANCER R ESEARCH,
Clinical Oncology, London, United Kingdom
The methodology for precision radiotherapy remains appropriate target volume delineation and treatment planning followed by reliable and accurate
dose delivery over the entire course of radiotherapy. It is well recognisedthat one of the limitations for precision radiotherapy whether it is deliveredby conformal or intensity modulated external beam radiotherapy is the presence of internal organ and target motion. This lecture will focus mainly on
external beam therapies rather than on brachytherapy but accurate definition of implanted volumes is also a crucial element of quality brachytherapy.
Amongst the recent strategic developments to account for temporal spatial
variations noted during radiotherapy delivery is the use of adaptive therapy.
The adaptive strategy uses repeated cross sectional imaging to determine
the magnitude of systematic and random components of target variability forthe individual patient. This imaging process often involves several feedback
loops that may be either on-line or off-line to reduce the spatial positional uncertainty inherent in the initial radiotherapy treatment planning scan. Oncethe magnitude of the temporal spatial variations is quantified, the modifications to the treatment plan can be initiated and implemented. This process
will still require verification and may need further optimisation where appropriate. Initially proposed and utilised in prostate radiotherapy, it was reported
to significantly reduce the mean systematic error from 4 mm to 0.5 mm. It has
since been investigated for other tumour subsites such as bladder, cervical aswell as liver and other deformable target sites. In bladder radiotherapy where
the target organ is the bladder, there can be substantial variation in both theposition and size of the organ of up t. there is good evidence to define individual patterns of bladder filling reliably. Using this information, it is possible
to predict the size of the bladder at the time of irradiation subsequent to theuse of daily volumetric imaging on the LINAC. This strategy termed predictive
organ localisation (POLO) has been tested and can be implemented clinicallyusing a library of predefined plans based on the a-priori knowledge of thedeformed bladder. Further refinement on this strategy Adaptive-POLO (APOLO) uses a wider range of library plans for daily on-line adaptive therapy.
This has been implemented in routine clinical practice and can be utilised
within a standard radiotherapy treatment slot. There will need to be education and training needs for radiotherapy staff. Other important issues include
resource allocation. The potential clinical benefits for these adaptive strategies will need to be fully assessed in clinical trials to quantify the magnitude
of benefit for our patients.
196 speaker
A CRITICAL OVERVIEW OF ARC THERAPY TECHNIQUES
T. Bortfeld1 , S. Webb2
1
M ASSACHUSETTS G ENERAL H OSPITAL & H ARVARD M EDICAL S CHOOL,
Radiation Oncology, Boston, USA
2
I NSTITUTE OF C ANCER R ESEARCH & R OYAL M ARSDEN NHS T RUST, Joint
Department of Physics, Sutton, United Kingdom
Purpose/Objectives: Two years ago we published an article on single-arc
IMRT (Rapidarc, VMAT), in which we concluded that single-arc IMRT is apromising technique but that it may compromise the quality of the dose distribution in complex cases if one limits the delivery time to 2 minutes (PMB
54:N9-N20, 2009). We also warned against too high expectations becausesome of the initial studies were driven by commercial as opposed to scientific interests, and suggested that more research work needs to be done tobetter understand the potential and limitations of single-arc IMRT. In the past
two years, many planning studies comparing arc IMRT with several other delivery techniques have been published, as well as relatively few algorithmic
advances of arc IMRT. The main objective of this teaching lecture is to review
the recent publications and thus the state of the art in arc IMRT. We will also
provide some more theoretical insights into the potential dosimetric efficiency
benefits of rotating the gantry during IMRT delivery.
Materials/Methods: We will begin with a brief historic review of arc IMRT. Interestingly, IMRT has its roots in arc therapy but the fixed field IMRT approach
using multiple static gantry positions has become more prevalent in the clinical implementation of IMRT. More recently, arc and single-arc IMRT delivery
have gained more interest again. We will focus in particular on publications
on arc IMRT from the past two years.
Results: The results presented in recent papers on arc-IMRT do not always
agree. However, a few common themes have emerged: the dose distributions
with arc IMRT are as good or sometimes better than with fixed field IMRT.
For complex cases, the use of multiple arcs provides a dosimetric advantage
compared with single-arc IMRT, and Tomotherapy plans are better still. The
delivery times with arc IMRT, especially with single-arc IMRT, are generally
shorter, though not by as much as indicated in the initial studies. Treatment

T EACHING LECTURE

S 77

planning for arc IMRT is more involved and takes substantially more time thanfor fixed field IMRT. These results represent a snapshot in time as far as boththe planning and delivery technologies are concerned. From a more fundamental theoretical point of view, arc and fixed field IMRT are dosimetricallyequivalent if "enough" time is provided for the delivery of the arc treatment,and "enough" beams (of the order of 10-20, i.e., more than the typical number) are used in the case of fixed field IMRT. "Cutting corners" will tip thebalance in either direction.
Conclusions: Overall, the debate about arc vs. fixed field IMRT reminds oneof the discussion of step-and-shoot vs. dynamic IMRT from 15 years ago.
Both techniques have certain pros and cons, but both can yield excellent results and they therefore have been and will be in clinical use in parallel.
197 speaker
IMAGE-GUIDED ADAPTIVE RADIATION THERAPY - MORE THAN A
VERIFICATION TOOL
J. J. Sonke1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands
Considerable geometrical uncertainties such as setup error, organ motion,
shape change and treatment response limit the precision and accuracy ofradiation therapy (RT). Consequently, the actually delivered dose does notequal the planned dose (what you see is not what you get).
Image guided radiotherapy (IGRT) is the process of 1) acquiring an imageof the patients anatomy, generally in the treatment room with the patient intreatment position, 2) comparing the treatment position with planned positionof the tumor, organs at risk or some surrogate and 3) correcting the treatment
position, generally with a couch correction. A large variety of imaging modalities are available for in-room imaging producing 2D, 3D, and/or 4D datasets.
Adaptive radiotherapy (ART) is the process where the patient’s treatment planis customized to patient-specific variation by evaluating and characterizing
the systematic and/or random variations through image feedback and including them in adaptive planning [1]. Where IGRT is generally limited to the
reduction of locally rigid variations, ART has the potential to reduce more
complex variations such as differential motion, shape changes and treatment
response. An important component of ART is deformable image registration
to bring the repeat imaging series into the same reference system for analysis
and dose accumulation.
Additionally, early response assessment on the functional aspects of the tumor and normal tissue’s can be incorporated in a re-plan once these havebeen proven to correlate with outcome.
Image guided and adapted RT (IGART) provides a powerful patient specific quality assurance (QA) platform verifying the patient’s position relative
to planning and making corrections if needed to better approximate to theoriginal treatment intent of the planning stage. Consequently, proving the efficacy of IGART in a clinical trial has ethical objections (in the standard arm,
the available technology to avoid geographic misses is not used). On theother hand, the increased precision and accuracy of IGART might be utilized
to reduce safety margins and personalize the treatment plan based on geometric and possibly functional characterizations.
The efficacy of such changes to the treatment plan relies on additional assumptions of disease spread distributions and dose-effect relationships. Suchchanges are therefore good candidates for clinical trials, where IGART is theenabling technology.
It is important to realize that despite the implementation of advanced correction strategies, treatment uncertainties will never be completely eliminatedand consequently safety margins will never be zero.
D. Yan et al. Computed tomography guided management of interfractional
patient variation, Seminars in radiation oncology 2005;15(3):168-79.

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Symposium
The necessity of quality assurance in brachytherapy
198 speaker
ACCIDENTS IN LDR AND HDR BRACHYTHERAPY
J. M. Cosset1
1
I NSTITUT C URIE, Radiation Oncology, Paris, France
In 2000, the International Commission on Radiological Protection (ICRP) released its publication 86, "Prevention of accidental exposures to patients undergoing radiation therapy". In this document, several specific chapters weredevoted to brachytherapy. The document in particular analyzed in details
the causes and factors contributing to accidental exposures in brachytherapy;
problems linked to the equipment, to the source ordering, delivery, calibration
and acceptance, problems with the treatment planning, the source preparation, the treatment delivery and the source removal. Accidents involving the
public and /or leading to environmental contamination were not forgotten, andfinally, generic lessons were drawn from the existing experience.
In 2005, the ICRP publication 97 concentrated more specifically on "Prevention of High-dose-rate brachytherapy accidents". It was estimated at that timethat about 500,000 HDR procedures were performed annually in the world,with over 10,000 HDR sources transported, with the resultant potential for
accidents. More than 500 accidents involving HDR brachytherapy had beenreported, human errors being the prime cause of radiation events.
Finally, also in 2005, ICRP published its publication 98; "Radiation safety
aspects of brachytherapy for prostate cancer using permanently implanted
sources", dealing with the permanent implantation of Iodin 125 or Palladium
103 seeds in the prostate for the treatment of selected localized prostate cancers.
The presentation will be mainly based on those three publications.
It will take as examples the worst accident occurring with an HDR procedure( the patient died and 94 persons were irradiated) , and the worst accident
with LDR implanted sources ( with 97 suboptimal implants in a cohort of 116
patients, during a 6-years period).
It will finally focus on the generic lessons to be drawn. In the same way it
has to be done in external radiotherapy, all precursor events, incidents or accidents in brachytherapy have to be immediately reported and analyzed, inorder to rapidly propose corrective procedures, to circulate the informationand to learn from experience.
199 speaker
EMERGENCY PROCEDURES: IS YOUR LIFE JACKET READY - OR
WILL YOU LEARN TO SWIM WHEN LANDING ON WATER?
A. Rijnders1
1

E UROPE H OSPITALS - S ITE 2 A LICE, Department of Medical Physics,
Brussels, Belgium

T UESDAY, M AY 10, 2011
recommendations such as AAPM TG 56 state that a trained medical physicist or radiation safety officer should be present during each HDR BT treatment procedure. Furthermore documented emergency procedures should bepracticed with the entire team at a regular interval (e.g. yearly). Before eachprocedure it should be checked that proper emergency equipment is in place,and that radiation monitors and signals are operational.
A few incidents with sources becoming disengaged from the source transfer
cable have been reported in the past, the most infamous happened at the
Indiana Regional Cancer Center in the US in 1992.
It could be stated that source and afterloader manufacturers have learned
from these events, and that the risk of such an event happening with modern
machines is certainly less than in the past. Manufacturers now guarantee anumber of fault-free source transfers which largely exceeds the actual numberof transfers that will be performed with a normally clinical operated afterloader
during the useful lifetime of the source. In this respect a note of care should
be made when using long lived isotopes such as Co60.
However other events can also lead to a source getting blocked in the patient,and the risk of such an event to happen can never be ignored. In Belgium e.g.
recently an incident was reported with a PDR-afterloader unit. At the end of
the treatment, during the source retraction the unit failed, causing the drive
motors to stop. However this failure was not recognized by the software andthe machine did not go in an error state. The problem was fortunately noticed
by a member of the nursing staff who was able to retract the source by pressing the emergency source retraction button. It was the first time that such anerror occurred on this type of unit, while this popular model of afterloader has
been on the marked for more then 2 decades.
The probability of a source getting disengaged or otherwise stuck in the patient may be extremely low, and other risks may show up to be more importantin a Failure Modes and Effects Analyses. But taking into account the severity of a possible incident, the possible harm to the patient and the relatively
low costs of installing appropriate emergency procedures, the existing recommendations should be applied and appropriate safety procedures should be
set up in every department. The entire BT staff should be trained at a regularbasis in applying these emergency procedures.
200 speaker
QUALITY ASSURANCE IN BRACHYTHERAPY
B. Al-Qaisieh
Abstract not received.

ESTRO-ESTS-ERS Joint symposium: Lung Cancer - What is the evidence that is being createdright now? - The best of clinical trials - Early stage
NSCLC
201 speaker

Although quality assurance has been getting more and more attention overthe last decades, the number of reported incidents in radiation oncology does
not seem to be decreasing. Partly this might be due to a better detection andreporting rate, but on the other hand the increasing input of advanced technology in radiotherapy also increases the potential of errors and malfunctions
and demands more stringent QA procedures.
A particular danger in any type of radiation therapy is that of an overdosage
due to administering the treatment during a longer time than intended, either
because of a human error (in the case of manually controlled devices), or
because of a technical failure of the radiation device (failure in the timer orradiation counter,&) or a combination of both.
When the irradiation beam is electronically generated, such as is the case inexternal beam radiotherapy using accelerators or in BT using electronic BT
sources, the irradiation can always be stopped with 100% certainty, ultimatelyby breaking the power circuit to the radiation device. When using radioactive
isotopes for BT however the possibility exists that the radioactive source orsources remain in the patient while the calculated treatment time has elapsed,leading to a continued irradiation.
In classical LDR applications, using manual (after)loading of the sources, thisrisk was most often linked to a human error, as the sources had to be manually removed once the treatment time had elapsed. Several incidents havebeen reported, and often lack of training, non-existing or insufficient procedures or lack of radiation detectors were one of the root causes of theseincidents. Due to the low dose rate (typically 60 cGy/h) consequences for thepatient were usually moderate or even negligible.
In afterloading techniques using a stepping source, and certainly in HDR
techniques, the danger is much higher. Due to the high reference air kerma
strength of the sources used (up to about 40 mGy/h for HDR sources) the
instantaneous dose rate in HDR implants can go up to 7 Gy/min at 1 cm
distance. If a source should for some reason remain stuck in the patient,critical doses leading to severe complications or even death can be reachedin the time span of several minutes, and emergency procedures should beapplied without delay. For this reason many (inter)national regulations and

LIMITED RESECTION
H. J. Hansen1
1
C OPENHAGEN U NIVERSITY H OSPITAL - R IGSHOSPITALET, Cardiothoracic
Surgery RT 2152, Copenhagen, Denmark
A resection can be limited both in the way the surgery is performed and by
the amount of tissue that is resected.
Video-Assisted Thoracic Surgery (VATS) lobectomy has become an accepted, safe and oncologically effective strategy in the surgical managementof early stage lung cancer. In Copenhagen 71% of all cancer lobectomies
were done by VATS in 2009.
On the short term basis VATS lobectomy is associated with less postoperative pain, shorter chest tube duration, less intra-operative blood loss, lees
need for blood transfusion less complications, shorter length of hospital stay,shorter stay in intensive care unit (ICU) and therefore it is cost effective to thehospital. It does allow the general or pulmonary marginal patient to have aprober lobectomy with lymph node handling performed.
On the long term basis VATS lobectomy is associated with less chronic pain,
better preservation of lung function, earlier return to daily activities and bettershoulder function. Furthermore VATS lobectomy is less immunosuppressive
and seems to facilitate the deliverance of adjuvant chemotherapy. The 5 year
survival rate is comparable to or maybe even better than lobectomy by thoracotomy.
As lung cancers are detected at a smaller size and in a peripheral location,lesser surgical resections may be an option. But the only randomized study
shows a benefit to a lobectomy over a sublobar resection. This study wasdone in an earlier era when tumors were often more central, many were
squamous cell cancers, and they were larger stage I tumors. More recent
data are retrospective and most often single-institution reports, but for carefully selected patients with small peripheral tumors, the outcomes for sublobar
resectionswhen possible, anatomic segmentectomyare excellent and compa-

T UESDAY, M AY 10, 2011

S YMPOSIUM

rable in cancer outcome to lobectomy. The optimal tumors for segmentectomy are those NSCLC that are well centered in the segment of interest andsized 2.0 cm or less. In addition, a patient who has limited pulmonary function (forced expiratory volume in 1 second less than 50% of predicted) or hasother lesions that will need to be resected should be given consideration fora segmental resection. The surgeon should always resect all intersegmental
lymph nodes in addition to the hilar and mediastinal nodes that are routinely
taken at the time of a lobectomy.
Using a video-assisted thoracic surgical approach to segmentectomy decreases the morbidity and hastens the recovery of patients having this operation relative to a thoracotomy. This technique can be easily learned bysurgeons who use video-assisted thoracic surgery to perform other operations.
Surgery is still the only way to offer total clearing of the affected lung tissue
and the possible affected local N1 and N2 lymph nodes. In selected centres
VATS lobectomy/segmentectomy now is the standard operation in early stagelung cancer and in near future it must be expected to be so throughout Europe. As the surgery is more demanding it is preferable, that it is done in highvolume centres by dedicated general thoracic surgeons.
202 speaker
STEREOTACTIC RT. THE NEW
PATIENTS WITH STAGE 1 NSCLC?
F. Lagerwaard1

STANDARDFOR

HIGH-RISK

1VU U NIVERSITY M EDICAL C ENTER, Radiation Oncology, Amsterdam,
Netherlands

Stereotactic ablative radiotherapy (SABR) or stereotactic body radiotherapy
has rapidly gained acceptance by chest physicians and patients as a curative
non-invasive treatment of early stage non-small cell lung cancer (NSCLC). In
countries where SABR implementation has taken place, this has led to detectable survival gains in stage I NSCLC on a population level [Palma 2010].
In addition, the availability of SABR in The Netherlands resulted in a change
in treatment utilization and patterns of care in elderly patients with a significant decrease in elderly patients being left untreated [Palma 2010].
Although no exact definition of SABR exists, it can be regarded as a form of
high-precision image-guided radiotherapy, involving the following features: (1)an individualized incorporation of tumour mobility, e.g. using 4-dimensional
CT scans or slow CT scans (2) accurate online patient setup using orthogonal
imaging, on-board kV imaging (OBI), cone-beam CT-scans or fiducial markers at the treatment delivery unit, (3) the use of up to 10 or more radiation
fields or intensity-modulated arcs to minimize normal tissue exposure and (5)the use of ablative doses, typically delivered in 3-5 fractions.
Despite the lack of a randomized trial, superior local control rates of around
90% reported after SABR in multicenter studies, phase I-II trials and single
institution series substantially exceed those obtained with conventional radiotherapy schemes. These excellent local control rates are particularly seen
in series where biological effective doses of above 100 Gy10 for tumour tissue have been used. The superiority of outpatient SABR, which is typicallydelivered in 3-8 fractions, was confirmed by recent a meta-analysis of observational studies [Grutters 2010].
SABR is well tolerated with fatigue and mild chest wall pain the most commonly reported patient-reported early symptoms. The incidence of late toxicity is also low with symptomatic radiation-induced pneumonitis and chestwall complications including chronic pain and rib fractures each observed inless than 5% of patients. Despite early reports of excessive toxicity after
SABR for centrally located lesions, the risk of such toxicity appears to be
low when appropriate risk-adapted fraction schemes are used [Timmerman
2006, Haasbeek 2010]. Both pulmonary function and health-related qualityof life are maintained following SABR, even in patients with considerable comorbidity [Stephans 2009, Senan 2010].
The excellent local control and low toxicity of SABR have challenged the assumption that surgery should be the preferred treatment for all potentiallyoperable patients with Stage I NSCLC. However, randomized prospective trials comparing surgery and SABR in operable patients have not been completed. Two single-arm phase II trials of SBRT in patients who are fit to undergo surgery have been completed, and the mature results of JCOG 0403
(NCT00238875) and RTOG 0618 (NCT00551369) are awaited. Data fromoperable Japanese patients who elected to undergo SABR in 14 Japaneseinstitutions over a 9-year period, reported 5-year overall survival rates of 72%
and 62%, respectively, for Stage IA and IB subgroups [Onishi 2010]. Preceding the outcome of randomized trials, we observe a growing number of potentially operable patients who, after discussion within local multi-disciplinary
tumor board meetings, are referred for SABR instead of surgery. The percentage of potentially operable patients in the Netherlands being referred for
SABR, particularly elderly patients with an increased surgical mortality risk,
has increased to 25% in recent years [Lagerwaard WCLC 2011].
In conclusion, SABR is rapidly replacing conventional radiotherapy as a curative treatment in medically inoperable patients. Until the outcome of prospective randomized clinical trials of SABR and surgery emerges, patients should
be routinely informed of the option of SABR as a possible curative alternative
to anatomical resection.

S 79

203 speaker
HIGH FREQUENCY ABLATION
T. DeBaere
Abstract not received.

204 speaker
ROLE OF ADJUVANT CHEMOTHERAPY
J. P. Sculier1
1
I NSTITUT JULES B ORDET (ULB), Intensive Care
Brussels, Belgium

Thoracic Oncology,

Adjuvant chemotherapy is today considered in Europe and America as a standard in the management of stages II and III resected non-small cell lung cancer (NSCLC). Its theoretic advantages are the assessment of the pathologicalstage, the eradication of micrometastases, the lack delay for surgery in caseof ineffective chemotherapy; its disadvantages are the drugs toxicity and theimpossibility of delivering for patients who become unfit due to surgery. The
decision to administer postoperative chemotherapy is based on the pathological TN. The level of evidence consists in multiple randomised trials andmeta-analyses with regimens containing platinum derivatives (1;2). The absolute 5-year survival gain is estimated around 5 to 10 %. In Japan, by using
the tegafur + uracil regimen, a benefit has been demonstrated for T1bN0M0
and stage IB NSCLC (3). Some subgroup analyses suggest for Caucasiansa significant survival benefit in patients with tumour size > 4 cm (4).
There is only one three-arm randomised trial having compared surgery alone
or neoadjuvant or with adjuvant chemotherapy (5), including mainly stage I
diseases and without survival benefit. According to meta-analyses of the literature, there seems to be no major differences between adjuvant and neoadjuvant chemotherapy (6). At very long-term, the benefit of chemotherapy seems
to be cancelled by early deaths due to the occurrence of multiple diseases (7).
The points that will be discussed during the presentation are the routine
indications for adjuvant chemotherapy after complete resection of NSCLC,
the implications of the new TNM staging system for good interpretation of
the guidelines on the topic, the choice between adjuvant and neoadjuvant
chemotherapy, the follow up to be performed after treatment.
References:
1. Meert AP, Sculier JP. What has the meta-analysis contributed to today’s standard of care in the treatment of thoracic malignancies? Lung
Cancer 2008 August;61(2):141-51.
2. Arriagada R, Auperin A, Burdett S et al. Adjuvant chemotherapy, withor without postoperative radiotherapy, in operable non-small-cell lungcancer: two meta-analyses of individual patient data. Lancet 2010
April 10;375(9722):1267-77.
3. Hamada C, Tsuboi M, Ohta M et al. Effect of postoperative adjuvant
chemotherapy with tegafur-uracil on survival in patients with stage
IA non-small cell lung cancer: an exploratory analysis from a metaanalysis of six randomized controlled trials. J Thorac Oncol 2009
December;4(12):1511-6.
4. Strauss GM, Herndon JE, Maddaus MA et al. Adjuvant paclitaxel plus
carboplatin compared with observation in stage IB non-small-cell lungcancer: CALGB 9633 with the Cancer and Leukemia Group B, Radiation Therapy Oncology Group, and North Central Cancer Treatment
Group Study Groups. J Clin Oncol 2008 November 1;26(31):5043-51.
5. Felip E, Rosell R, Maestre JA et al. Preoperative chemotherapy plus
surgery versus surgery plus adjuvant chemotherapy versus surgery
alone in early-stage non-small-cell lung cancer. J Clin Oncol 2010
July 1;28(19):3138-45.
6. Lim E, Harris G, Patel A et al. Preoperative versus postoperative
chemotherapy in patients with resectable non-small cell lung cancer:
systematic review and indirect comparison meta-analysis of randomized trials. J Thorac Oncol 2009 November;4(11):1380-8.
7. Arriagada R, Dunant A, Pignon JP et al. Long-term results of the international adjuvant lung cancer trial evaluating adjuvant Cisplatin-based
chemotherapy in resected lung cancer. J Clin Oncol 2010 January
1;28(1):35-42.
Adjuvant chemotherapy is today considered in Europe and America as a standard in the management of stages II and III resected non-small cell lung cancer (NSCLC). Its theoretic advantages are the assessment of the pathologicalstage, the eradication of micrometastases, the lack delay for surgery in caseof ineffective chemotherapy; its disadvantages are the drugs toxicity and theimpossibility of delivering for patients who become unfit due to surgery. The
decision to administer postoperative chemotherapy is based on the pathological TN. The level of evidence consists in multiple randomised trials andS 80

S YMPOSIUM

meta-analyses with regimens containing platinum derivatives (1;2). The absolute 5-year survival gain is estimated around 5 to 10 %. In Japan, by using
the tegafur + uracil regimen, a benefit has been demonstrated for T1bN0M0
and stage IB NSCLC (3). Some subgroup analyses suggest for Caucasiansa significant survival benefit in patients with tumour size > 4 cm (4).
There is only one three-arm randomised trial having compared surgery alone
or neoadjuvant or with adjuvant chemotherapy (5), including mainly stage I
diseases and without survival benefit. According to meta-analyses of the literature, there seems to be no major differences between adjuvant and neoadjuvant chemotherapy (6). At very long-term, the benefit of chemotherapy seems
to be cancelled by early deaths due to the occurrence of multiple diseases (7).
The points that will be discussed during the presentation are the routine
indications for adjuvant chemotherapy after complete resection of NSCLC,
the implications of the new TNM staging system for good interpretation of
the guidelines on the topic, the choice between adjuvant and neoadjuvant
chemotherapy, the follow up to be performed after treatment.
References:

T UESDAY, M AY 10, 2011
imaging modality especially suitable for monitoring of intra-tumoral changes
during a course of hypofractionated radiotherapy. However, at this moment
microenvironmental changes visualized and quantified by means of PETimaging need to be validated to allow interpretation of imaging techniqueswith intermediate resolution (such as PET/CT).

Breast cancer - What is the evidence that is being
created right now? - The best of clinical trials
206 speaker
UPDATE AND STATUS REPORT ON HYPOFRACTIONATION AND
ACCELERATION (START AND CANADIAN STUDY)
T. J. Whelan

1. Meert AP, Sculier JP. What has the meta-analysis contributed to today’s standard of care in the treatment of thoracic malignancies? Lung
Cancer 2008 August;61(2):141-51.

Abstract not received.

2. Arriagada R, Auperin A, Burdett S et al. Adjuvant chemotherapy, withor without postoperative radiotherapy, in operable non-small-cell lungcancer: two meta-analyses of individual patient data. Lancet 2010
April 10;375(9722):1267-77.

207 speaker

3. Hamada C, Tsuboi M, Ohta M et al. Effect of postoperative adjuvant
chemotherapy with tegafur-uracil on survival in patients with stage
IA non-small cell lung cancer: an exploratory analysis from a metaanalysis of six randomized controlled trials. J Thorac Oncol 2009
December;4(12):1511-6.
4. Strauss GM, Herndon JE, Maddaus MA et al. Adjuvant paclitaxel plus
carboplatin compared with observation in stage IB non-small-cell lungcancer: CALGB 9633 with the Cancer and Leukemia Group B, Radiation Therapy Oncology Group, and North Central Cancer Treatment
Group Study Groups. J Clin Oncol 2008 November 1;26(31):5043-51.
5. Felip E, Rosell R, Maestre JA et al. Preoperative chemotherapy plus
surgery versus surgery plus adjuvant chemotherapy versus surgery
alone in early-stage non-small-cell lung cancer. J Clin Oncol 2010
July 1;28(19):3138-45.
6. Lim E, Harris G, Patel A et al. Preoperative versus postoperative
chemotherapy in patients with resectable non-small cell lung cancer:
systematic review and indirect comparison meta-analysis of randomized trials. J Thorac Oncol 2009 November;4(11):1380-8.
7. Arriagada R, Dunant A, Pignon JP et al. Long-term results of the international adjuvant lung cancer trial evaluating adjuvant Cisplatin-based
chemotherapy in resected lung cancer. J Clin Oncol 2010 January
1;28(1):35-42.

205 speaker
RADIOBIOLOGY AND MOLECULAR RESPONSE IMAGING IN
HYPOFRACTIONATION
J. Bussink1
1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Radiation Oncology,
Nijmegen, Netherlands
Introduction: One of the main microenvironmental charateristic that is responsible for treatment failure is tumor cell hypoxia. The extent of tumor cell hypoxia may have marked implication if the number of radiotherapy fractions is
reduced. Therefore, the introduction of hypofractionation in clinical practice
may increase the necessity to visualize these resistant hypoxic tumor areas.
Hypoxia and treatment resistance: To overcome hypoxia related treatment
resistance localizing and quantifying hypoxia is necessary. To reduce thenegative effect of tumor cell hypoxia, radiotherapy can be combined with hypoxia mimicking agents such as nimorazole or hypoxic cytotoxins, such as
tirapazamine can be applied. Also, radiotherapy can be applied together
with hypoxia decreasing procedures such as hyperoxic gas breathing during treatment or stimulation tumor blood flow. The more recent introductionof Intensity Modulated RadioTherapy, IMRT, allows specific boosting of tumor subvolumes that may harbor radioresistant tumor cells. Visualizing thesesubvolumes by means of PET imaging for this purpose has great potential.
Several PET tracers are available for hypoxia imaging. These tracers aremainly 2-nitroimidazol derivatives such as FMISO and FAZA. It was shown inseveral solid tumors that the amount of tracer accumulation decreased overthe course of treatment before changes in conventional imaging modalities
were measurable.
Conclusions: One of the main advantages of PET is the potential to monitor tumor metabolism during treatment. This allows to prospectively assesschanges in the tumor microenvironment that are not visible on CT. Making thisT UESDAY, M AY 10, 2011
Conserving Therapy of Early Breast Cancer: 10-Year Results of the Randomized Boost Versus No Boost EORTC 22881-10882 Trial J Clin Oncol 25 (22):3259-3265, 2007.
S. COLLETTE, L. COLLETTE, T. BUDIHARTO, J.C. HORIOT, P.M. POORTMANS, H. STRUIKMANS, W. VAN DEN BOGAERT, A. FOURQUET, J. J.
JAGER, W. HOOGENRAAD, R.P. MUELLER, J. KURTZ, D.A.L. MORGAN,
J.B. DUBOIS, E. SALAMON, R. MIRIMANOFF, M. BOLLA, M. VAN DER
HULST, C. WARLAM-ROODENHUIS, H. BARTELINK. Predictors of the riskof fibrosis at 10 years after breast conserving therapy for early breast cancer- A study based on the EORTC trial 22881-10882 "Boost versus no Boost".
Eur J Cancer 44 (17): 2587-2599, 2008.
208 speaker
EVALUATION OF RADIOTHERAPY IN HIGH-RISK BREAST CANCERPATIENTS GIVEN ADJUVANT SYSTEMIC THERAPY. A 25-YEAR
UPDATE OF THE DANISH BREAST CANCER COOPERATIVEGROUP DBCG 82B&C TRIAL.
M. Overgaard1
1

UPDATE OF THREE MAJOR PHASE III RANDOMIZED TRIALS FROMTHE EORTC BREAST AND RADIOTHERAPY GROUP.
H. Bartelink1 2 , S. Litiere1 2 , S. Collette1 2 , L. Collette1 2 , J. Bogaerts12 , E.
Rutgers1 2 , N. Bijker1 2 , M. Donker1 2 , E. van Werkhoven1 2
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands
2
EORTC H EADQUARTERS, Brussels, Belgium
Three major Phase III randomized trials from The EORTC Breast and Radiotherapy group were updated, all three trials investigated the role of radiotherapy in early breast cancer.
1. Comparing radical mastectomy (RM) with breast conserving therapy (BCT)In this trial 902 patients were randomized between RM and BCT, the previous
analysis revealed a significant higher loco-regional recurrence rate but no difference in overall survival or the time to distant metastasis rate after a medianfollow-up of 13.4 years.
This updated analysis demonstrated that with a median follow-up of 22.1
years, the BCT and mastectomy groups had similar curves with respect totime to DM and overall survival (p = 0.23 and p = 0.23 respectively). Adjustment for clinical tumor size (≤ 2cm versus > 2cm), pathologic axillary lymph
node status (negative versus positive) and age (≥ 50 years old versus <50
years old) did not change these conclusions.
2. Breast-Conserving Treatment With or Without Radiotherapy in Ductal
Carcinoma-In-Situ:
After complete local excision (LE), 1010 women with DCIS were randomly
assigned to no further treatment or radiotherapy (50Gy). One thousand ten
women with mostly (71%) mammographically detected DCIS were included.
The 10 years follow up data demonstrated that radiotherapy after LE for DCIS
continued to reduce the risk of LR, with a 47% reduction at 10 years. All patient subgroups benefited from radiotherapy. If mature for analysis, data froma recent update will be presented at the meeting Data from 15year follow up
data will be presented at the meeting.
3. Boost versus no Boost trial in stage I and II breast cancer
A total of 5,318 patients with microscopically complete excision followed bywhole-breast irradiation of 50 Gy were randomly assigned to receive either aboost dose of 16 Gy (2,661 patients) or no boost dose (2,657 patients), witha median follow-up of 10.8 years. A nomogram was developed for predicting the cost benefit for giving a boost dose predicting the individual chanceon fibrosis and local recurrence. For local recurrence the following factors
associated with local recurrence were included in the nomogram: diameter(per mm: HR 1.01), the presence of accompanying DCIS (HR 1.96) and histological high grade (HR 1.21), systemic treatment with hormones (HR 0.59)
or chemotherapy (HR 0.68), treatment with boost (HR 0.49) with age as themost dominant factor (HR 0.4 for older than 50 years).
J.A. van Dongen, A.C. Voogd, I.S. Fentiman, C. Legrand, R. Sylvester, D.
Tong, E. van der Schueren, P.A. Helle, K. van Zijl, H. Bartelink. (2000) Longterm Results of a Randomized Trial Comparing Breast-Conserving Therapy
with Mastectomy: European Organization for Research and Treatment ofCancer 10801 Trial. Journal of the National Cancer Institute 92(14) pp 11431150.
Bijker N, Meijnen P, Peterse JL, Bogaerts J, Van Hoorebeeck I, Julien JP,
Gennaro M, Rouanet P, Avril A, Fentiman IS, Bartelink H, Rutgers EJ.
EORTC Breast Breast-conserving treatment with or without radiotherapy inductal carcinoma-in-situ: ten-year results of European Organisation for Research and Treatment of Cancer randomized phase III trial 10853–a study
by the EORTC Breast Cancer Cooperative Group and EORTC RadiotherapyGroup.Cancer Cooperative Group. J Clin Oncol. 2006 Jul 20;24(21):3381-7.
Harry Bartelink, Jean-Claude Horiot, Philip M. Poortmans, Henk Struikmans,
Walter Van den Bogaert, Alain Fourquet, Jos J. Jager, Willem J. Hoogenraad,
S. Bing Oei, Carla C. Warlam-Rodenhuis,Marianne Pierart, and LaurenceCollette
Impact of a Higher Radiation Dose on Local Control and Survival in Breast-

A ARHUS U NIVERSITY H OSPITAL, Oncology, Aarhus C, Denmark

On behalf of the DBCG Radiotherapy Group.
Aim: To evaluate the role of postmastectomy radiotherapy in the presenceof adjuvant systemic therapy the Danish Breast Cancer Cooperative Group(DBCG) conducted a randomized trial in high-risk pre- and postmenopausal(<70 years) breast cancer patients between 1982 and 1990.
Methods: A total of 3,083 patients with pathological stage II and stage III
breast cancer were after mastectomy randomly assigned to receive adjuvant
systemic therapy and postoperative irradiation to the chestwall and regional
lymph nodes (1,538 pts), or adjuvant systemic therapy alone (1,545 pts). Preand menopausal patients received 8-9 cycles of CMF with an interval of 4
weeks, whereas postmenopausal patients received tamoxifen 30 mg daily forone year. The median potential follow-up time was 23 (range 20-28) years.
The endpoints were loco-regional control, freedom for distant metastases andoverall survival.
Results: Overall the 25-year actuarial probability of loco-regional recurrence
was 14% in irradiated patients versus 46% in patients who received adjuvant systemic therapy alone (p<0.0001), (Hazard Ratio (HR): 0.23 (95% [cfl0.22-0.24]. Distant metastasis probability at 25 years was 58% in irradiatedpatients compared to 69% in non-irradiated (p<0.0001), HR: 0.80 [0.73-0.88].
These figures were also reflected in a superior survival of the irradiated patients (24% versus 18% at 25 years (p<0.0001), HR: 0.81 [0.75-0.88]. A multivariate analysis demonstrated that postmastectomy irradiation resulted in asignificant improvement in freedom from any recurrence and overall survival,
irrespective of menopausal status, tumor size, number of positive nodes andhistopathologic grading. Radiotherapy did not result in excess death, and radiation related side-effects were minor.
Conclusion: Adjuvant systemic therapy in high-risk breast cancer patientstreated with modified radical mastectomy can not sufficiently prevent locoregional recurrences. The study definitely indicates that optimal treatment ofhigh-risk breast cancer can only be achieved if both loco-regional and systemic tumor control are aimed for. Therefore radiotherapy has an importantrole in the multidisciplinary treatment of breast cancer.

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S 81

Symposium
Intra-fraction challenges - prediction models
209 speaker
MANAGEMENT OF BREATHING MOTION THROUGH MULTILEAFCOLLIMATOR TRACKING
A. Krauss1 , S. Nill1 , U. Oelfke1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Heidelberg, Germany
Intrafraction organ motion especially due to breathing can compromise thebenefits of modern highly conformal radiotherapy deliveries such as IMRT.
Dynamic MLC tracking represents a promising technique to restore this highdose conformity in the presence of organ motion, without affecting the delivery efficiency like respiratory gated radiotherapy.
For MLC tracking the target motion is monitored continuously and the aperture of the MLC is adapted in real-time to the reported target position. Because the leaves then move in synchrony to the organ motion, the techniquecame to be called "breathing leaves".
A variety of motion monitoring systems have been used for MLC tracking,such as external infrared markers, implanted electromagnetic transponders,marker-based kilo- and megavoltage fluoroscopy imaging as well as combinations of them. In phantom studies geometric tracking accuracies partly
even below 1mm have been reported. The beneficial impact of MLC tracking
on the delivered dose distributions has been proven for various delivery techniques such as step-and-shoot IMRT, dynamic IMRT and rotational therapy.
However, there are some limitations in tracking accuracy due to hardware
constraints. Especially the compensation of target motions perpendicular tothe leaf travel direction is limited by typical leaf widths of 5mm on the one
hand and typical maximum leaf travel velocities of several cm/s on the other
hand, which prohibit rapid opening or closing of leaf pairs.
Another challenge is posed by the possibly large reaction times of an integrated tracking system. For the system latency, defined as the time lag between an actual target motion and the system response, values ranging from
160ms to 600ms have been reported for the different MLC tracking systems.
The latency has to be compensated by forward prediction of the breathing
signal. Despite the use of elaborated prediction algorithms, latency remains
a major source of tracking inaccuracies at least for systems with a high latency.
In this presentation different MLC tracking systems with various motion monitoring devices will be introduced and their respective strengths and limitations will be discussed. The breathing motion prediction problem and several
commonly used predictors will be introduced. Strategies to correct for more
complex forms of organ motion such as target rotations and deformations will
also be addressed.
210 speaker
YET ANOTHER APPROACH TO PURSUE A MOVING TUMOUR: THE
GIMBALED LINEAR ACCELERATOR SYSTEM
T. Depuydt1 , K. Poels1 , D. Verellen1 , M. De Ridder1
1

UZ B RUSSEL , V RIJE U NIVERSITEIT B RUSSEL, Radiotherapy Department,
Brussels, Belgium
In radiation therapy, intra-fraction motion results in significant geometric anddosimetric uncertainties in the therapeutic dose delivery treating thoracic andabdominal tumors. To accommodate these issues and to assure adequate
dosimetric coverage of the tumor, geometric safety margins can be applied
which incorporate the entire motion. However, the use of large margins,
where healthy tissues are present, prevents dose escalation as healthy tissue toxicity becomes an increasingly important limiting factor. Tumor dose
escalation has been shown to be beneficial in terms of outcome when it canbe combined with a decreased in excessive irradiation of surrounding normal
tissue and critical structures to minimize complications. Beam modulation devices can help deliver complex radiation fields that can accurately conform to
the PTV whilst at the same time sparing critical structures. The drawback ofsuch treatments known as intensity modulated radiation therapy (IMRT) andto a lesser extent conformal radiotherapy is the presence of dose distribution
with large gradient between the organs at risk and the tumor. If the tumor
moves it could receive a significantly lower dose than planned and the organ
at risk a significantly higher dose. Such event could negate the expected benefit of dose shaping and modulation. This talk focuses on one of the methods
to address organ motion referred to as real time tumor tracking (RTTT). RTTT
is believed to be able to bring together the goals of dose escalation and surrounding tissue sparing for moving tumors.
Most of the RTTT solutions presented exploit existing radiation therapy equipment in new ways to adapt the beam to the tumor motion or adapt the tumor
motion to the therapeutic beam . A first approach is respiratory gating where
the therapeutic beam is switched on only when the moving tumor is adequately covered and switched off otherwise. A drawback here is that the duty
cycle usually is no more than 20 to 30 % which leads to very long treatment times. In an attempt to increase the duty cycle approaches such asactive breathing control (ABC) or breath-holding techniques have been used.

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However, patients affected by tumors in lungs and abdomen, where intrafraction motion is most significant, may experience difficulties even with normal breathing, hence both breath-holding and ABC have limited applicability
and may cause discomfort to the patients.
The most technically challenging method with potentially the best result is toaccommodate tumor motion during irradiation with a real-time tumor tracking
radiation delivery system. The principle is that the tumor should stay in thesame relative position with respect to the beam. This can be accomplishedby continuous adaptation of the patient/tumor position using the patient support system (PSS) with respect to a static beam or by real-time adaptationof the treatment beam itself to the tumor position. The technical feasibilityof using a PSS to compensate for measurable tumor motion with respect
to the treatment beam has been demonstrated. Whilst some studies seemto indicate that the moving patient does not lead to any discomfort and caneven be ’relaxing’ , the influence of counteracting part or all the motion on
patient/tumor position behavior during this continuous repositioning requires
further investigation. Indeed compensation of the motion in one direction may
lead to a motion in another direction. Other approaches with a fixed patient
position were presented where the dynamic behavior of the PSS were takenover by dynamic operation of the multi-leaf collimator (DMLC) or a roboticarm based linear accelerator gantry. An important issue in DMLC tracking is
the orientation of the tumor motion with respect to the leaf motion direction
and the limited speed of the leafs. This introduces a difference in tracking
performance between tracking a tumor moving inline or perpendicular to theleaf trajectories. The resulting combination of DMLC intensity modulation andarc therapy could potentially lead to unrealistic demands on the MLC in termsof dynamics.
Yet another approach to compensate for breathing related tumor motion has
been proposed. The VERO system, a novel platform for image guided stereotactic body radiotherapy, is a joint product of BrainLAB and MHI. A new typeof 6 MV linac with attached MLC is mounted on an O-ring gantry. Orthogonal
gimbals hold the linac-MLC assembly, which allows pan and tilt motions of
the therapeutic beam enabling tracking of moving tumors. Beside an ExacTrac IR camera system, the VERO system is equipped with a dual kV imaging
systems attached to the O-ring at 45◦ from the MV beam, allowing simultaneous acquisition of orthogonal X-rays images and fluoroscopy for guidanceof tumor tracking. A decoupling of the tracking motion from the DMLC based
intensity modulation, seems to be a very promising option. Key to the success of such system is its ability to actually track organ motion consistently
with the required accuracy, moving the full weight of the linac-MLC assembly.
211 speaker
REAL-TIME RESPIRATORY TUMOUR TRACKING BY A ROBOTIC
SYSTEM
M. Hoogeman1 , J. Nuyttens1 , N. van der Voort van Zyp1 , P. Levendag1 , B.
Heijmen1
1
E RASMUS M EDICAL C ENTER R OTTERDAM, Radiation Oncology, Rotterdam, Netherlands
Real-time tumour tracking is performed with the Synchrony Respiratory Tracking System, which is part of the CyberKnife Robotic Radiosurgery System(Accuray Inc., Sunnyvale, CA). The system combines X-ray imaging of internal markers or the tumour itself with a continuously updated external breathing signal. A correlation model relating the external breathing signal with the
motion of the tumour position provides a real-time update of the beam position. The correlation model is built just before the start of each treatment
fraction and is adaptive by updating the model during the fraction. The beamcannot be positioned instantaneously. Data processing, communication to
the robotic controller, and the inertia of the robotic manipulator and the linear
accelerator causes a time delay of 115 ms. A prediction method applied tothe breathing signal compensates for this delay.In this presentation a description will be given of the applied prediction algorithms. Error analysis basedon actual patient data will be presented for the various methods and system
lag times. The best results were obtained for a hybrid mode of operation thatcombined the output of three prediction algorithms into one prediction. For
this method the prediction error, expressed as 1 standard deviation, was below 1 mm for a wide range of respiratory amplitudes.Other sources of errorthat are part of the real-time tracking will be discussed as well. These error
sources are amongst others the correlation model, relating internal tumourand external chest/abdomen motion, and the use of implanted markers assurrogate for the tumour position. For the correlation model that uses both alinear or polynomial fit to the internal and external motion data, it was foundthat internal tumour motion of 44 patients could be modelled to within 2.5 mm(1 SD), while the error without compensation would increase to 8.1 mm. The
stability of markers in relation to the tumour was investigated in 42 patients.
The median marker displacement with respect to the tumour was small (1.3mm). However, marker displacements >5 mm occurred in 12% of markers.
These displaced markers could be identified by a change in the distance between markers and subsequently disabled such that tumour localization was
not compromised.

T UESDAY, M AY 10, 2011

Symposium
QA for rotational therapy
212 speaker
QA FOR TOMOTHERAPY, PROPOSALS OF THE TASK GROUP 148
OF THE AAPM
S. Vynckier1
1

UCL C LINIQUES U NIV. S T.L UC, Department of Radiation Therapy andRadiooncology, Brussels, Belgium
On behalf of the AAPM (American Association of Physicists in Medicine) Task
Group 148.
Objective: Helical Tomotherapy was introduced for clinical applications some
5-6 years ago. It is a new treatment modality including a specific helical IMRT
treatment planning and delivery. Moreover, it does provide IGRT based on an
integrated MVCT scan. Its design, hardware and software are unique. Therefore the AAPM (American Association of Physicists in Medicine) Task Group148 was established to review this treatment modality and to propose newrecommendations for Quality Assurance (QA).
Outline of the Report: The report is divided in 3 main chapters describing
the uniqueness of the treatment imaging, treatment planning and treatment
delivery part. Each chapter describes in detail the proposed QA tests withrecommendations for tolerances and periodicity. A final chapter provides asummary on the QA recommendations and orders them with respect to daily,
monthly, quarterly and annually QA procedures.
Conclusion: This report provides clear information and guidance to the medical physicist to be involved in routine QA aspects of the Tomotherapy unit. It
is the intension to make these procedures uniform among Tomotherapy users
and to provide recommendations towards tolerances and frequencies. This
Tomotherapy equipment presents several modalities i.e. the imaging part, thetreatment planning part and the linear accelerator and delivery part. QA for allthese procedures is closely connected and is covered in detail in this review
report.
213 speaker

EPID-BASED QUALITY ASSURANCE FOR VOLUMETRIC MODULATED ARC THERAPY
L. Hoffmann1 , M. B. Kyed Jørgensen1 , J. Petersen1 , L. H. Praestegaard1 ,R. Hansen1 , L. P. Muren1
1
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
Purpose/Objective: Quality assurance (QA) of the radiotherapy (RT) equipment is an important part of the treatment of cancer patients. Thus, guidelines focusing on QA have been proposed for various parts of the RT process,including the dynamic delivery of treatment plans.[1] Intensity-modulated radiotherapy (IMRT) is a well established technique to deliver a conformal dose
distribution while minimizing the dose to the normal tissue. This technique
has recently been further developed to the volumetric intensity modulated radiotherapy technique (VMAT) which is an alternative IMRT method. VMAT
includes features such as variable dose rate and gantry speed in addition to
the beam modulation achieved with complex patterns of multi-leaf collimator(MLC) motion in IMRT. Although VMAT is an extension of the IMRT-dynamic
MLC technique, additional quality control (QC) is required. A large number ofstudies have addressed IMRT machine QC, but only a few studies have been
published on machine QC for VMAT. For commissioning and QC, Ling et al.[2]proposed three test plans: 1) a picket fence (PF) 2) a dose rate versus gantry
speed (DRGS) test and 3) a dose rate versus MLC leaf speed (DRMLC) test.
The PF test was originally proposed by Chui et al.[3] for QC of the positioningof the leaves of a dynamic MLC. This test has been used as standard QC for
IMRT. These three tests evaluate the VMAT performance in a stepwise manner, so for example if the PF test or the DRGS test fails, the reason should befound and solved before evaluating the following test. The tests may easily
be performed with the on board electronic portal imaging device, the EPID,
and thus, be part of a routine machine QC program designed to ensure theaccurate delivery of VMAT. The PF, the DRGS and the DRMLC tests primarily focus on the dynamic performance of the accelerator. These tests do not
replace standard geometric machine QC of e.g. the gantry angle or the collimator angle that might influence the results of the PF, DRGS and DRMLC
tests. Moreover, neither of the tests evaluates the absolute dosimetry of theaccelerator or the absolute position of the MLCs. Furthermore, these tests
do not replace the patient-specific QC for which additional measurements
are needed.
Methods and materials: The three QC tests proposed by Ling et al, havebeen investigated for Varian accelerators in three studies performed by Ling
et al, Fredh et al, and Jrgensen et al.[2,4,5] Ling et al. used films for the measurements, whereas Fredh et al. and Jrgensen et al. used the EPID. Ling
et al.[2] performed the tests once at one accelerator whereas Fredh et al.[4]performed the tests eight times for each of three accelerators. The study described by Jrgensen et al.[5] aimed at setting up tolerance levels for the threetests by repeating the tests six times for each of nine accelerators. The PF

T UESDAY, M AY 10, 2011
test used for IMRT is a control of the leaf position and the distance between
two facing leaves. The MLC leaf pairs sweep synchronously across a fieldwith a constant distance of 1 mm between the leaves. Ten times, the leaves
stopped irradiating a small strip to a higher dose. Both visual and analyticalmethods have been used for the evaluation of the PF test. In the DRGS andDRMLC tests, different combinations of dose rate, gantry speed and MLC
leaf speed were used to deliver identical doses to separate parts of the EPID.
The tests were evaluated by looking for deviations in the constancy of themeasured dose for the preset combinations of dose rate, gantry speed and
MLC leaf speed.
Results: The three studies find that errors of 0.3 to 0.5 mm in MLC leaf position are detected by the PF test. For the DRGS test maximum deviations of
1 to 2 % was observed in the three studies, revealing a high reliability of thetest. For the DRMLC test, the maximum errors found in the three tests differedconsiderably between the three studies. Fredh et al.[4] observed maximum
errors of 5 % and rejected the test for QC of VMAT. These findings were notconfirmed in the other studies where maximum errors of 1 to 2 % were found.
Conclusion: The PF, the DRGS and the DRMLC tests offer a convenient,fast and accurate machine QC program for linear accelerators used for VMAT.
The MLC positional tolerance and the deviations of the DRGS and DRMLC
speed tests are within the recommendations of 0.5 mm and 3 % of the ESTRO guidelines[1]. These tolerances seem to be compatible to the performance of the accelerators in most cases.[2,4,5] The use of the EPID for QC
is very fast and efficient compared to film measurements. However, communication problems between the EPID and the accelerator may be an issue.
Patient specific QC may be performed instead of the proposed machine QC
program. But this is very time consuming and it is desirable to skip the patient
specific QC after an implementation period.
M. Alber, S. Broggi, C. de Wagter, I. Eichwurzel, P. Engstrm, C. Fiorino, D.
Georg, G. Hartmann, T. Kns, A. Leal, H. Marijnissen, B. Mijnheer, M. Paiusco,
F. Shez-Doblado, R. Schmidt, M. Tomsej, H. Welleweerd, "ESTRO booklet no.
9: Guidelines for verification of IMRT," ESTRO (2008).
C. C. Ling, P. Zhang, Y.Archambault, J. Bocanek, G. Tang and T. LoSasso,"Commissioning and quality assurance of rapidarc radiotherapy delivery system," Int. J. Radiat. Oncol. Biol. Phys. 72(2) 575-581 (2008).
C.-S. Chui, S. Spirou and T. LoSasso, "Testing of dynamic multileaf collimation," Med. Phys. 23(5), 635-641 (1996).
A. Fredh, S. Korreman, P. Munck af Rosenschld, "Automated analysis of images acquired with electronic portal imaging device during delivery of quality
assurance plans for inversely optimized arc therapy," Radiother. and Oncol.
94, 195-198 (2010).
M. K. Jrgensen, L. Hoffmann, J. B.B. Petersen, L. H. Pregaard, R. Hansen,
and L. P. Muren,"Tolerance levels of EPID-based quality control for volumetricmodulated arc therapy" submitted for publication.
214 speaker
SPECIFIC QA ISSUES FOR TOMOTHERAPY: INTRODUCTION OF
NEW QA TOOLS
V. Althof1 , D. Kramer1 , R. Westendorp1 , T. Nuver1 , A. Minken1 , M. Ikink1 ,G. Hilgers1
1
R ADIOTHERAPEUTIC I NSTITUTE RISO, Deventer, Netherlands
Purpose: To review filmless QA tools for rotational radiotherapy using the
Tomotherapy system.
Materials and Methods: Helical Tomotherapy differs from conventional linear accelerators in a number of ways, i.e. helical delivery, binary MLC andcouch movement during radiation delivery. Tomotherapy provides QA tools
which are integrated in the planning- and delivery system. An example is the
Delivery QA (DQA) which allows to recalculate the patient plan on a phantom
and to compare ionization chamber and film measurements with dose calculations. New QA procedures, with user configured MLC delivery patterns(sinograms) and procedure parameters, were developed. These procedures
use the build in MVCT detector to measure open lateral beam profiles andphantom- and patient transmission profiles.
Transmission measurements of a steplike phantom, allows for measurementof beam energy consistency, couch speed, laser position, slit width and synchronization of gantry with couch movement and gantry with leaf dynamics.
Because of the high detector sample frequency (max. 300 Hz), the system issuitable to detect highly dynamic processes like the movement of the leaves(transit time 20 ms) and to measure with high temporal accuracy the abutment of an interrupted treatment and the completion of the treatment.
Simultaneously with the sampling of the lateral beam profile during beam on,
85 system signals are sampled. Profiles and system signals are available
for trend analysis. Most of these developments are incorporated in the Tomotherapy TQA™product.
We developed a number of additional tools, like a monitor of system signals
during delivery of a QA procedure and a sinogram analyzer that analyses
the treatment planning solution by showing the distribution of beamlets passing through a voxel selected in the patient CT study. A hardware tool is developed which allows to diagnose problems in the pulse forming circuit bymeasurement of health signals during rotational procedures with a standard
non-rotating oscilloscope.

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Transmission measurements of the patient allows for reconstruction of thetreatment sinogram and hence subsequent 3D in vivo dose reconstruction
using the patient MVCT or kVCT. This has the potential to replace DQA measurements.
Results: Examples of the QA tools and test results of prereleased Tomotherapy software for in vivo dose reconstruction will be given. Trending data of
QA items was obtained for a 4 year period on both of our Hi-Art II machines
and will be shown as well.
Conclusion: The Tomotherapy system offers the user tools to design his
own QA treatment procedures and to collect system data which can be usedin trend analysis. The MVCT detector is crucial for fast QA procedures anddose reconstruction.
215 speaker
QA FOR VOLUMETRIC-MODULATED ARC THERAPY AT THE
NKI-AVL
A. Mans1 , I. Olaciregui1 , R. Rozendaal1 , R. Tielenburg1 , R. Vijlbrief1 , J. J.
Sonke1 , B. Mijnheer1 , M. van Herk1 , J. Stroom1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology , Amsterdam, Netherlands
Purpose: Since early 2008, all treatments with curative intent are verified
by means of portal dosimetry in the Netherlands Cancer Institute-Antoni van
Leeuwenhoek Hospital (NKI-AVL). If possible, verification is performed invivo, otherwise pre-treatment. In august 2009, VMAT was clinically introduced in our department, and the portal dosimetry method was adapted toallow verification of VMAT treatments. Currently, VMAT is used routinely forprostate and stereotactic lung and brain treatments. Here we report on thefirst year of clinical experience with EPID-based VMAT verification, and compare results to IMRT.
Methods and Materials: For IMRT, the portal dose is back-projected per
beam to a plane parallel to the EPID, intersecting the isocentre, and compared to a corresponding slice from the planned dose distribution of thatbeam. The transmission (necessary for the back-projection) is determinedfrom the ratio of portal and open images.
Three modifications were needed to adapt the back-projection method to
VMAT. 1) Continuous acquisition of EPID data in "movie-mode". 2) Calculation of the transmission from CT data. 3) Back-projection in 3D. With thesemodifications, an EPID movie acquired during VMAT delivery can be converted into a 3D dose distribution in the planning CT scan.
Comparison of EPID-reconstructed and planned dose distributions for VMAT(IMRT) is done by a 3D (2D) γ -evaluation method (3%/3mm); γ -evaluation
statistics is performed within the 50% isodose surface (20% isodose line) of
the planned dose distribution. In 3D, the 50% isodose was chosen to exclude
the buildup region.
VMAT plans are created using the ’SmartArc’ module of Pinnacle 9.0 (Philips
Medical Systems), and delivered using Elekta SL20i accelerators with standard MLC. Brain (1x18 Gy) treatments are verified pre-treatment on a slab
phantom, lung SBRT and prostate treatments are verified in vivo.
Results: The average values of the dose difference at the isocentre, themean γ and the percentage of points with γ <1 are presented in Table 1
for both VMAT and IMRT for the three treatment sites. There is a small
but systematic underestimation of the isocentre dose by the portal dosimetry method. VMAT and IMRT show similar values for the isocentre dose difference, although the standard deviation is somewhat larger for VMAT verification. This is probably caused by an increased susceptibility to anatomicalchanges when calculated transmission is used. The γ statistics are remarkable similar, especially considering the γ evaluation dimensionality: 2D for
IMRT and 3D for VMAT.
Conclusion: Our portal dosimetry method was successfully implemented forroutine dosimetric verification of VMAT, both pre-treatment and in vivo. The
main VMAT verification results (isocentre dose difference and γ statistics) aresimilar to IMRT. Consequently, VMAT treatments are included in our (in vivo)
portal dosimetry programme for every single treatment with curative intent.

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Symposium
IMRT Planning and verification
216 speaker
DOES INVERSE PLANNED INTENSITY MODULATION IN BREAST
RADIOTHERAPY BRING ANY CLINICAL BENEFIT?
H. P. van der Laan1 , E. Korevaar2
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Technology, Groningen, Netherlands
2
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Department of Radiation Oncology, Groningen, Netherlands

T UESDAY, M AY 10, 2011
IMRT technique with coplanar VMAT has reduced the physical workload of radiation therapy technologists, since non-coplanar IMRT techniques required
the technologist to repeatedly enter the treatment room to adjust treatment
couch angles. In addition, delivery of the radiation treatment with VMAT allows in-line monitoring with cone-beam computed tomography, which is now
introduced in our clinic. This allows a better evaluation of the delivered doseand also results in a further decrease in total treatment time since the final
monitoring CBCT scan can be omitted.

217 speaker
VMAT VS. CONVENTIONAL IMRT TECHNIQUES FOR SBRT OF
LUNG CANCER
A. Holt1 , C. van Vliet-Vroegindeweij1 , J. S. A. Belderbos1 , E. M. F. Damen1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
In a steadily growing number of centers worldwide inoperable patients with
peripheral early-stage lung cancer not yet spread to lymph nodes are treatedusing hypo-fractionated radiation schemes. Typically, the treatment is delivered in 3 to 10 fractions with fractions doses of up to 18 Gy. Using IMRT
(Intensity Modulated Radiation Therapy) techniques with limited number ofsegments an overall treatment time of up to 30-45 minutes is needed per
fraction. The advent of VMAT (Volumetric Modulated Arc Therapy) offers interesting possibilities for the radiation treatment of patients with early-stagelung tumors but also primary brain tumors as well as brain and liver metastases, which can often be treated with SBRT (Stereotactic Body Radiation
Therapy). With VMAT the treatment is delivered continuously while the treatment head is moving around the patient, resulting in a major reduction indelivery time.
We explored the potential of coplanar VMAT for SBRT of lung cancer as compared to conventional non-coplanar and coplanar IMRT techniques. Using
VMAT plan quality and sparing of organs at risk including healthy lung tissue,
spinal cord, esophagus, brachial plexus and heart is comparable or even better compared to both conventional IMRT techniques. When applying fraction
doses as high as 18 Gy, dose to skin becomes an issue. Experimental determination of the maximum dose to any point using an anthropomorphic phantom showed that the maximum dose to the skin is comparable for coplanar
VMAT and non-coplanar IMRT, and slightly increased for coplanar IMRT. With
VMAT the irradiation time is significantly reduced by about 70% to now 6-7
minutes compared to 20-25 minutes with non-coplanar IMRT. The total treatment time that includes positioning the patient before treatment by means of
4D CBCT (Cone-Beam Computed Tomography) using tumor match, deliveryof the treatment and monitoring after completed treatment, could be reduced
to 20-25 minutes with VMAT.
The shortened irradiation time reduces the chance for shifts in patient andtumor position during delivery of the fraction, which will result in less dose
blurring and therefore an improved dose distribution in the target. In addition,
the major reduction in total treatment time greatly improves the comfort ofthese mostly elderly patients, often suffering from other diseases that renderthem inoperable. At the same time, VMAT enhances patient throughput inthe clinic without compromises to treatment quality. Moreover, it may open
up radiation therapy as therapy option to lung cancer patients that otherwise
would have left untreated. Furthermore, replacing the previous non-coplanar

Proffered paper
GEC Proffered Papers 5: Brachytherapy in anal,
rectal, bladder and soft tissue sarcomas
219 oral

M EDICAL U NIVERSITY V IENNA , AKH, Department of Radiotherapy,
Medical Univ Vienna, Vienna, Austria

PULSED DOSE RATE BRACHYTHERAPY OF ANAL CARCINOMA:RETROSPECTIVE DATA WITH LONG TERM FOLLOW-UP
S. Van Brussel1 , H. Janssen1 , M. De Brabandere2 , A. Nulens2 , E. Van
Limbergen1 , G. Defraene3
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Radiotherapy
Oncology, Leuven, Belgium
2
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Physics, Leuven,
Belgium
3
U NIVERSITY H OSPITAL G ASTHUISBERG, Leuven, Belgium

Intensity modulated radiotherapy utilizes computer optimized dose distributions with beam data that are transferred through a computer network fromthe treatment planning system to the accelerator for automatic delivery of radiation. In this process there are very few intrinsic possibilities for manual
inspection and verification of the delivered dose albeit there are many steps
where both systematic and random errors can be introduced. In several European countries there are legal aspects based on EURATOM directive 97/43
for independent quality assurance (QA) procedures and their implementation
into national radiation protection and patient safety legislation.
The basic criteria for an IMRT verification method as part of a quality system in advanced radiation therapy are accuracy, reliability, efficiency, simplicity in commissioning, simple to apply in clinical routines and independence
from other systems and data used in the clinic. Compared to IMRT witha static gantry, verification of rotational IMRT is needs to take into accountthe increasing complexity of the beam application (dose rate, leaf movement,
gantry movement).
During the last decade a number of ESTRO physics booklets have been published giving recommendations for quality procedures in radiotherapy. Tworecent ESTRO booklets focus specifically on IMRT, i.e. booklet no 9 "Guidelines for the verification of IMRT" summarizes various experimental dosimetrictechniques while booklet no. 10 "Independent Dose Calculations Concepts
and Models" is focused on dose verification by applying independent dose
calculations (IDC) using advanced beam models. The examples presented
in ESTRO booklet no 9 reflect the large variety of IMRT QA tests performedin daily practice around the world having already some years of clinical experience with IMRT. ESTRO booklet 9 also formulates guidelines concerning
type and tolerances of tests to be performed for IMRT verification in relation
to the required accuracy, as well as the various strategies for patient-specific
IMRT verification, and provides insight into a number of possible pitfalls andpotential errors experience in different departments.
There is a growing interest in using calculation techniques for IMRT verification. IDC have been used for a long time as a routine QA tool in conventional
radiotherapy using empirical algorithms. But to achieve high accuracy with an
IDC tool for IMRT it is recommended applying more general models than the
traditionally used factor based models. Such models will facilitate to detectboth large, mainly random deviations, but also frequent smaller deviations
which be found by statistical analyses of QA data.
The choice of a specific quality control technique for IMRT depends on several clinical aspects and it is still a matter of debate whether calculations,
measurements or a combination of both is the best choice for an individual
clinic.

Purpose: External beam irradiation combining PDR boost brachytherapy is
an attractive and feasible way to preserve the sphincter in patients with anal
carcinoma. With the introduction of CT and MRI guided brachytherapy moreaccurate information is available on dose optimisation. In this study we aim toevaluate the data of long term follow-up of PDR brachytherapy in UZ Leuven.
Materials: From February 1994 to October 2010, 41 patients (median ageof 57.5 years) were treated for squamous cell anal carcinoma. The TNM
classification includes: 4 T1, 24 T2, 12 T3 and 1 T4; 19 N0, 15 N1, 6 N2 and 1
N3; all M0. All patients received external beam irradiation (mean dose 45.13
Gy) to the posterior pelvis (16 patients + inguinal nodes) with concomitantchemotherapy, usually the 5FU-Mitomycine Nigro schedule. After a meaninterval of 18.5 days, interstitial PDR brachytherapy was given to the residual
tumourbed. A mean dose of 17.0 Gy (range 15 - 20Gy) was given to 85%
of the Mean Central Dose. For 22 patients planning was performed using 2D
orthogonal X-rays, 5 had a CT scan and 14 had a MRI guided brachytherapy.
Results: With a mean follow-up of 48 months (range 1m - 146m), crude
overall survival was 80.5% (colostomy-free survival 83%). Local recurrence
was seen in 6 patients (85.4% local control rate): 5 in field relapses and
1 geographical miss. Comparing 2D brachytherapy planning with 3D gives
no difference in local control. The local relapse rate (LRR) was significant
higher in T3-T4 tumours (LRR T3-T4 tumours 23.1% vs LRR T1-T2 tumours
10.7%). We observed also a relationship between complete tumour responsat time of brachy and better local control (Complete responders had 8% LRR,
partial responders 25% LRR). Regional recurrence occurred in 17% of thepatients. Metastatic disease was seen in 14.6% of the cases.The treatment
was well tolerated for most patients: grade I or II acute and late skin, GU
and GI toxicity (RTOG). There was only 1 patient with acute transient grade
3 skin toxicity (decubitus gluteus muscle due to immobilisation). No patient
required colostomy for complications. There was 1 patient with a transient
grade 3 ulceration treated with hyperbaric oxygen therapy. 3 patients hadintermittent grade 3 soiling problems. 2 of the 28 female patients suffer from
dyspareunia. Grade 3 complications are well correlated with a pulse size ≥60
cGy/pulse and a higher brachy dose. With CT and MRI planning we observea significant difference in frequency of soiling (5.2% 3D vs 31.8% 2D) andtransient bleedings ( 5.2% 3D vs 27.2% 2D).
Conclusions: Short split course CRT and PDR brachytherapy are associatedwith good local control, colostomy-free survival and long term QOL. No grade
4 complication is reported. CT and MRI guided brachytherapy gives lesscomplications but no significant difference in local control. Results will becompared with our LDR patients treated from 1983 until 2010 and the current
literature.

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GUIDELINES FOR THE VERIFICATION OF IMRT
D. Georg1
1

Only a limited number of European institutions currently uses inverse planned
intensity modulated radiotherapy (ip-IMRT) as the standard treatment forbreast cancer patients. However, this is expected to change in the near future because an increasing number of institutions implemented ip-IMRT forvarious other cancers. Furthermore, professionals increased their knowledge and skills and radiotherapy procedures have been optimized for ip-IMRT.
This gives rise to the question whether ip-IMRT might also bring benefit forbreast cancer patients. To answer this question we must first define our reference treatment technique. At our institute, we compared ip-IMRT to threedimensional conformal radiotherapy (3D-CRT) and we found that it makes adifference which 3D-CRT method is used in actual practice. In fact, many
institutions acquired specific skills to deliver sophisticated forward planned
3D-CRT, e.g., by using additional manually shaped segments to optimize thedose distribution, reducing the gap between 3D-CRT and ip-IMPT. Similarly,
we also have to define the specific ip-IMRT method that will be used. Do weapply Direct Aperture Optimization? What is the maximum number of segments we allow for a treatment plan? Which and how many beam directions
are used? Is a class solution used with a fixed set of IMRT objectives ordoes one use a trial-and-error adaptive optimization method to improve thetreatment plan? It appears that ip-IMRT generally brings benefit, but that theactual gain depends on a variety of factors. In this presentation we aim toshow that the additional benefit of ip-IMRT also differs between patients, because patient specific anatomy and pathology may have a major impact on
the difference in resulting dose distributions.

T UESDAY, M AY 10, 2011

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REAL-TIME 3D TREATMENT PLANNING FOR IMAGE INTERSTITIAL
ADAPTED HDR BRACHYTHERAPY (IABT) BOOST IN ANAL CANCER
P. Niehoff1 , F. A. Siebert1 , B. Schniewind2 , J. Schumacher1 , V. Kahlke3 , G.
Kovács4
1
UK-SH, C AMPUS K IEL, Klinik für Strahlentherapie und Radioonkologie,
Kiel, Germany
2
UK-SH, C AMPUS K IEL, Klinik für Allgemeine Chirurgie und Thoraxchirurgie, Kiel, Germany
3
P RAXIS FÜR P ROKTOLOGIE, Kiel, Germany
4
UKSH, C AMPUS L ÜBECK, Interdisciplinary Brachytherapy unit, Lübeck,Germany
Purpose: Primary radiotherapy in form of external beam radiotherapy (EBRT)
combined with chemotherapy and/or local dose escalation by brachytherapy
enables anal sphincter preservation and can avoid permanent colostomy. In
this study we present our improved technique of real-time 3D treatment planning using transrectal ultrasound (TRUS) guided 3D target definition, treatment planning and delivery. Aim of this prospective study was to obtain advantages compared to our previous preplanning technique.
Materials: 40 Patients (pts.) with histological proven primary cancer of
the anal canal without distant metastases were treated. A complementary
course of 45 Gy EBRT to the pelvic region with conventional fraction, andP ROFFERED PAPER

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in case of N+ or T3-T4 in combination with chemotherapy, was applied. 2-4
weeks after EBRT a high-dose-rate IABT boost was administered to the tumor
bed/residual tumor using two fractions of 4 Gy. Fraction dose was defined at
the surface of the TRUS visible target volume; needle geometry followed therules of the Paris system. For positioning of the needles the RASHA - applicator was used, which contained also the 360◦ transrectal ultrasound unit.
VITESSE® / BrachyVision® software package was used for 3D reconstruction
and dosimetry.
Results: We analyzed 80 implants with online real-time treatment planning
procedure. Precise postimplant 3D reconstruction as well definition of thetarget and the implanted needles using online image capture (1 to 5 mm
slice thickness) was possible. Furthermore, time consumption of real-timeplanning procedure was 10 to 20 minutes compared to the time consumptionof the preplanning method with typically 90 minutes duration. The mean valueof V100 was 92%, V90 of 95.6% and the mean CI was 0.92. Compared toour previous pre-planning method using between 2-7 needles (mean 3.3) weused now 3-9 needles (mean 4.5) for homogenous PTV coverage.

Conclusions: TRUS-guided IABT boost using real-time treatment planningenables high quality of 3D target definition, and dosimetry as well offers
shorter performance time.
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DOSE ESCALATION WITH CONTACT X-RAY (CXRT) AND ORGANPRESERVATION IN RECTAL CANCER. LYON R96-02 RANDOMIZEDTRIAL
J. P. Gérard1 , C. Ortholan1 , O. Chapet2 , P. Romestaing3
1
C ENTRE A NTOINE L ACASSAGNE, Department of Radiotherapy, Nice,
France2
C ENTRE H OSPITALIER LYON S UD, Pierre Benite, France3
H ÔPITAL P RIVÉ M ERMOZ, Lyon , France
Purpose: Randomized trials with standard neoadjuvant treatments in rectal
cancer T2-3 have failed to increase sphincter or organ preservation (1). To
succeed in such a conservative treatment the hypothesis is that a clinicalcomplete response (CCR) must be achieved before surgery. The Lyon R9602 randomized trial tested this hypothesis using a high dose escalation withCXRT.
Materials: Between 1996 and 2001, 88 pts with T2-3 M0,endorectal ultrasound staged rectal adenocarcinoma in the distal rectum were randomized
between preoperative external beam radiotherapy (EBRT) 39 Gy/13F/2,5w
vs EBRT with a 90 Gy/3F endoluminal local boost with CXRT.The end point
was conservative treatment. CCR was evaluated using digital examination
and rigid rectoscopy perfomed by two radiation oncologists (PR,JPG) (2).
Results: The median follow up is 10 years. Tumor stage was well balanced
between arms with 26 T2 and 62 T3 (not exceeding 50% of rectal circumference). The rate of CCR was 2% with EBRT alone and 29% with CXRT
(p:0.001). The rate of 10 year survival without colostomy was respectively
29% (EBRT) and 61% (CXRT+EBRT) (p: 0.001). Out of 34 patients who had
a conservative treatment after CXRT, 10 had organ preservation(rectum andanus) either with RT alone(+/- interstitial brachytherapy) or with trans anal
local excision (TLE). In all these patients the rectal function was scored as
good or excellent. At 10 years there was no difference between both groups
in terms of local recurrence (13%) or overall survival (55%).

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Conclusions: Clinical complete response is significantly increased by dose
escalation with CXRT. It translates into significant increase in sphincter andorgan preservation. It appears possible to propose for T2N0 patients a conservative approach using CXRT + EBRT with concurrent Capecitabine(CAP
50 regimen)(3) with a "watch and wait" policy in case of CCR. This strategy
will be tested in the international phase II "CONTEM 2" clinical trial(4) . 1)
Bujko K Radioth Oncol 2006;80:42) Gerard JP J Clin Oncol 2004;22:24043)
Gerard JP J Clin Oncol 2010;28:16384) Lindegaard J Clin Oncol 2008;19:738
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HIGH DOSE RATE ENDORECTAL BRACHYTHERAPY BOOST IN
TREATMENT OF MEDICALLY UNFIT PATIENTS TO UNDERGO
SURGERY FOR RECTAL CANCER
T. Vuong1 , N. Tamim1 , B. Bahoric1 , G. Stroian2 , S. Devic1
1

J EWISH G ENERAL H OSPITAL, Radiation Oncology, Montreal, Canada
SMBD J EWISH G ENERAL H OSPITAL, Radiation Oncology , Montréal,
Canada2

Purpose: The management of medically unfit patients with rectal cancer toundergo surgery is challenging. Conventional external beam radiation treatment (EBRT) has been associated with local control of only 25-30%. The
present work reports on our institutional results using high dose rate endorectal brachytherapy (HDRBT) as a boost after external beam radiation therapy.
Materials: From August 2005 to September 2010, 41 newly diagnosed rectal
cancer patients, with a median age of 82 years (65-93 years), were treatedwith a radical course of EBRT and HDRBT boost. There were 22 men and19 women. The pretreatment staging included MRI in 37 patients and endoscopic ultrasound (EUS) in 4 patients with contra-indications to MRI. There
were 7 patients with T2, 34 with T3 and 1 with T4 disease. Only eight patients
had radiologically positive lymph nodes and two patients had metastases atpresentation.The EBRT component consisted of 40 Gy in 16 fractions for 31
and 45 Gy in 25 fractions for 10 patients. The treatment was delivered witha three field technique and a mixed beam of 6 and 18 MV photons. Afterthe completion of the EBRT, the pelvic MRI was repeated in preparation for
the HDRBT boost, which was given on weekly basis: 35 patients received
30 Gy in 3 fractions, 3 patients received 20 Gy in 2 fractions and another 3
patients with very low lesions received 15 Gy in 3 fractions. The prescribed
dose was delivered using a micro-Selectron remote afterloader (Nucletron,
Veenendaal, the Netherlands) employing an iridium-192 source with a nominal activity at installation of 370 GBq (10 Ci). An Intracavitary Mold Applicator(Nucletron) of cylindrical shape is used for treatment delivery.
Results: The EBRT course was well tolerated with 24% (10/41) grade 1 and
76% (31/41) Grade 2 GI toxicity. Also, there were 30% grade I and 70% grade
II skin toxicity incidences. With a median follow up time of 14 months, the local control rate was 76% (31/41). Two patients underwent salvage surgery,one local excision and the other an abdominal perineal resection. Long-term
toxicity was observed in 7 patients (17%) with rectal bleeding (G3) and stenosis in 3 patients (7%). One patient with recurrent tumor had a recto-vaginal
fistula.
Conclusions: Our results suggest that HDRBT boost for medically unfit patients with rectal cancer has an acceptable toxicity profile with a favorable
local control rate, when compared to historical EBRT alone data.
223 oralDA VINCI – CURIE CONNECTION. EARLY EXPERIENCE OF
LAPAROSCOPIC/ ROBOT ASSISTED BRACHYTHERAPY IMPLANTATIONS (LBI) IN SOLITARY BLADDER CANCER.
E. Van der Steen-Banasik1 , G. Smits2
1
ARTI - A RNHEMS R ADIOT HERAPY I NST., Arnhem, Netherlands
2
A LYSIS Z ORGGROEP, Urology, Arnhem, Netherlands
Purpose: Following modern developments in the field of surgery we decided
to postpone the conventional open approach for brachytherapy of bladdercarcinoma and introduce laparoscopy, finally da Vinci®Robot assisted, forthis specific indication. Here we describe the implementation of the techniqueand report the first experiences and early toxicity of laparoscopic implantationof brachytherapy catheters in the bladder wall.
Materials: Eleven patients with solitary transitional cell carcinoma (TCC) of
the bladder ( N=9) and distal TCC of the ureter (N=2, laparoscopic nefroureterctomy in one simultaneously) were treated with a combination of external beam irradiation (3 fractions of 3,5 Gy or 20 fractions of 2 Gy in T1/T2 tumours respectively) and brachytherapy (equivalent 60 or 30 Gy respectively)
in Arnhem Radiotherapy Institute and Alysis Zorggroep Hospital Arnhem between June 2009 and December 2010. During surgery, laparoscopy was
combined with cystoscopy. In this way, the tumour area could also be identified outside the bladder by the laparoscopic view. The borders of the clinicaltarget volume (CTV) were then marked by titanium clips and 3-4 brachytherapy catheters were inserted in this target region. For this purpose we designed needles, in cooperation with Nucletron®, allowing an easy abdominal
wall passage (out-in and in-out) and bladder wall placement of the cathetersby adjusting length, curve and thickness of the needle and its attachment with

T UESDAY, M AY 10, 2011
the catheter.
Results: In 8 patients the duration of laparoscopic procedure decreased subsequently from 2 hours to nearly 1 hour. No adverse events were observed
during hospitalisation which lasted from 5 to max 7 days. This is in contrast to 8-38 days hospitalisation in the conventional procedure (N=96). The
subsequent 3 patients treatment was Robot assisted. Because of this new
approach the duration of the procedure extended again to 2 hours (presumably temporarily). The planning procedure did not differ from the procedureused in conventional brachytherapy. We observed no early toxicity. Up till
now we observed one patient with a persistent lesion, treated 3 month after
completing of radiotherapy with TURB.
Conclusions: LBI is feasible when using modified catheters, specific designed needles and performing cystoscopy simultaneously. Da Vinci assistance makes the approach of difficult located lesions possible. The reductionof patient’s burden seems very promising and the results are at this point satisfactory. We intend to continue LBI, however we are aware of the preliminary
character of our experiences, findings and results.
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TOXICITY, PATTERNS OF FAILURE & OUTCOME IN SOFT TISSUESARCOMAS TREATED WITH PERIOPERATIVE HDR BRACHYTHERAPY & EBRT
I. San Miguel1 , M. Gaztañaga1 , M. E. Rodríguez1 , M. Pagola Divasson1 , M.
Cambeiro1 , L. Arbea Moreno1 , M. Fernandez Sanmamed1 , M. San Julian2 ,R. Martínez-Monge1
1
C LINICA U NIVERSITARIA DE N AVARRA, Oncología, Pamplona, Spain
2
C LINICA U NIVERSITARIA DE N AVARRA, Orthopaedic Department, Pamplona, Spain
Purpose: This study was undertaken to determine factors predictive of toxicity, patterns of failure and survival in a mature series (median f/up: 4.1y) of 60
adult patients with soft tissue sarcomas (STS) of the extremity and superficial
trunk (E&ST) treated with combined perioperative high-dose rate brachytherapy (PHDRB) and External Irradiation (EBRT) at average Eq2Gy doses of≥70Gy.
Materials: Patients with STS of the E&ST were treated with surgical resection and PHDRB (16 or 24Gy) for negative and close/microscopically positive
surgical resection margins, respectively. EBRT (45 Gy) was added postoperatively. Adjuvant chemotherapy with ifosfamide and doxorubicin was given topatients with advanced high-grade tumors.
Results: Grade 3 toxic events were observed in 18 patients (30%) and Grade
4 events in 6 patients (10%). No Grade 5 events were observed. Treatment
Volume 150 (TV150) was significant for grade ≥3 toxic events on multivariate
analysis (HR: 2.8; p=0.017). The rates of local control, locoregional control
and distant control at 9 years were 77.4%, 77.6% and 63.8%, respectively.
On multivariate analysis, local control and locoregional control correlated withpositive margin status (HR: 4.4; p=0.036 and HR: 4.8; p=0.007, respectively)
and distant metastases correlated with tumor size (HR: 9.5; p=0.004). Nineyear disease-free survival and overall survival rates were 47.0% and 61.5%,
respectively. On multivariate analysis, disease-free survival rates were lower
among patients with tumors larger than 6cm (HR: 3.9; p=0.005) and with positive margins (HR: 2.5; p=0.043) while overall survival rates only decreased
with increasing tumor size (HR: 7.5; p=0.011).
Conclusions: The use of PHDRB allows to reach high Eq2Gy radiation
doses of ≥70Gy. However, dose escalation does not seem to offset the deleterious effect of margin positivity. Due to the impact of positive margins on
local control, locoregional control and disease-free survival, strategies aimed
to decrease the rate of R1 resections are warranted.

T UESDAY, M AY 10, 2011Materials: 3 patients with varying pre-implant prostate volumes (38cc, 21cc,42cc) and a varying number of seeds (resp 76, 62 and 42) were included.
T2-TSE (3mm), T1-GE (4mm) and CT (3mm) images were acquired and imported in Variseed8.0. 3 interobserver studies were set up:1) Contouring: 8
physicians delineated the prostate gland on CT and T2. CT was contoured
first, MRI >2 weeks later. For each patient one ref contour was defined on
CT and T2 by 2 radiologists specialised in urology.2) Seed localisation was
done by 7 physicists on T1 and CT, using the implant plan details as well
as 2 postplan x-rays. Seeds were localised manually and with the CT seedfinder tools, first on T1, and >2 weeks later on CT. For each patient 2 expert
physicists defined a consensus ref seed geometry on CT and T1. 3) Fusion
was done by 6 physicists for technique b, c and d, using seeds (if possible)
and anatomical landmarks. T1+T2 fusion was almost a zero-match (aligned
coord. systems) corrected for minor patient motions. Technique d involved
an intermediate step with T1, existing of a seed based CT+T1 match and anearly zero-match of T1+T2. 2 physicists defined consensus fusions for the
3 patients.
Results: For all patients the ref D90 (ref contours, ref seeds, ref fusion) was
highly technique dependent (D90 patient mean in figure).1) The mean observer volumes of the contoured prostates corresponded well with the refvolumes: resp 47cc vs 44cc for CT and 39cc vs 38cc for T2. The SDref forcontouring (1 SD w.r.t. ref volume) was largest for CT (23%), but also surprisingly large for MR (17%). This resulted in large SDref values for D90 for
all techniques. The large variability in CT contouring corresponds well withliterature, and can be attributed to the lack of soft tissue contrast. The large
variability in MRI contouring was mainly due to different interpretations onwhat parts belong to the prostate. 2) Seed reconstruction: the interobserver
variability in D90 was very small for all techniques, except for T1+T2 (values
in figure).3) Fusion: interobserver variability was quite large, especially fordirect fusion of CT+T2 where clearly corresponding landmarks were missing(seeds hardly visible).

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PROSTATE POST-IMPLANT DOSIMETRY: INTEROBSERVER VARIABILITY IN SEED LOCALISATION, CONTOURING & FUSION
M. De Brabandere1 , K. Haustermans1 , F. Van den Heuvel1 , P. Hoskin2 , F.
A. Siebert3
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Radiation
Oncology, Leuven, Belgium
2
M OUNT V ERNON H OSPITAL, Department of Clinical Oncology, Northwood
Middlesex, United Kingdom
3
U NIVERSITY H OSPITAL S-H C AMPUS K IEL, Clinic of Radiotherapy, Kiel,
Germany
Purpose: Post-implant evaluation of prostate seed implants requires optimal
seed localisation and accurate delineation of anatomical structures. Depending on the technique used, uncertainties in seed definition, contouring and fusion affect the dosimetric accuracy, but are not well known. The GEC-ESTRO
groups BRAPHYQS and PROBATE performed a joint study to evaluate theinterobserver uncertainties of 4 CT- or T1/T2 MRI-imaging techniques: a) CT,b) T1+T2, c) CT+T2, d) CT(+T1)+T2.

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n=10/48/103, hormonal therapy (HT) in n=80/108/91.The evaluation of all patients was performed in 1st July 2010, mean observation time was 38,79
months (12-96). Phoenix definition of progress/recurrence was used. In caseof failure, examination of failure causes was performed by technical and clinical tools including MRI, Cholin PET/CT, prostate biopsy and others.
Results: From n=1023, 5 pats were lost to follow up. N=1018 patients were evaluable.In LR/IR and HR group, bNED (dAmico) was
96,66%, 92,04 % and 91,88 %.bNED in initial PSA <4/4-10/>10-20/>2040/>40 was 95,56%/95,40%/90,20%/89,70% and 83,40%.bNED in Gleason< =6/3+4=7a/4+3=7b/>=8 was 95,66%/92,31%/92,96% and 83,11%.Reasons of progression in LR/IR/HR group were local (7/9/3), lymphatic (1/8/6),
systemic (2/9/5) or unknown (6/1/1).
Time to progress in LR/IR/HR
group was 50(15-82)/26 (3-60)/38,75 (8-60) months. Comparison of different risk grouping systems for LR/IR and HR groups showed minor deviations for dAmico grouping (96,66%/92,04%/91,88%) vs. Mt. Sinaigrouping (96,90%/92,17%/91,80%) and vs.
Seattle/MSKCC grouping(96,10%/93,20%/89,90%) although some patient shifts were observed.
Conclusions: Prostate brachytherapy with Iodine 125 stranded seeds shows
excellent results in low, intermediate and high risk prostate cancer, althoughdata also from the learning curve patients are integrated. Of course, data
still have to mature to show long time results.Addition of antihormonal treatment or external radiation for oncological reasons seems only necessary
in selected patients with very advanced intermediate risk or high risk cancer.Good results of brachytherapy in higher gleason grades and PSA-levels
deserve special attention with regard to some limitations in actual clinicalguidelines.There is strong evidence, that results from different riskgroup systems can be compared reliably.Details will be discussed. Data will be shownin correlation to tumor specific prediction plots (e.g. Kattan nomograms) andgeneral age related survival statistics.
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LONG TERM RESULTS OF A PROSPECTIVE DOSE ESCALATIONPHASE-II TRIAL: INTERSTITIAL PDR- BRACHYTHERAPY AS
BOOST FOR INTERMEDIATE- AND HIGH-RISK PROSTATE CANCER
V. Strnad1 , S. Lettmaier1 , M. Lotter1 , S. Kreppner1 , A. Strnad1 , R. Fietkau1
1
U NIVERSITY H OSPITALS OF E RLANGEN, Department of Radiation
Oncology, Erlangen, Germany

Conclusions: The dosimetric parameters for prostate postimplant evaluation showed large technique-dependent interobserver variabilities. Contouring and fusion seem to be the ’weak links’ in the procedure. This could beapproached by respectively training and automated fusion software.
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GEC Proffered Papers 6: Prostate

P ROFFERED PAPER

RESULTS AFTER 8 YEARS OF CURATIVE I-125 BRACHYTHERAPY
IN 1023 CONSECUTIVE PATIENTS WITH LOW, INTERMEDIATE AND
HIGH RISK PROSTATE CANCER
J. Zimmermann123
1
P RAXISZENTRUM A LSTERTAL , D RES . Z IMMERMANN, Abtlg. Brachytherapie, Hamburg, Germany
2
ON BEHALF OF THE INTERDISCIPLINARY P ROSTATE B RACHY G ROUP ,Hamburg, Germany
3
K ATH . M ARIENKRANKENHAUS, Hamburg, Germany
Purpose: To evaluate the effectiveness of I-125 brachytherapy with stranded
seeds in low (LR), intermediate (IR) and high risk (HR) prostate cancer, primarily assessed by the risk group scoring of dAmico.
Materials: Between 6/2002 and 6/2009, a total of n=1023 patients with diagnosis of locally restricted prostate cancer (diagnosis <= 6 months prior totreatment) with a mean age of 67.3 years (43-84) was treated in our institute by I-125 stranded seeds with an activity of 0.15 to 0.82 mCi. Reference
doses were 145 Gy in monotherapy and 108 Gy in combination with EBRT
45 Gy. Patients with insufficient dose after d-30 CT-scan received a second
implant (n=29).N=482 Patients showed low, n=341 intermediate and n=200high risk of tumorprogression according to the dAmico system. In LR/IR and
HR, monotherapy was applied in n=474/305/74 pats, EBRT was added in

Purpose: To review long-term single institution experience with pulsed-doserate brachytherapy dose escalation study in patients with intermediate andhigh risk prostate cancer.
Materials: We treated a total of 130 patients for intermediate and high risk
prostate cancer using PDR-brachytherapy as a boost after external beam
radiation therapy to 50.4 Gy. . Boost brachytherapy doses was escalated
from 25 to 35 Gy - 33 pts. received 25 Gy (total dose 75 Gy), 63 pts. 30
Gy (total dose 80 Gy) and 34 pts. 35 Gy,(total dose 85 Gy) given in one
session. PSA-recurrence-free survival according to Kaplan-Meier using the
Phoenix definition of biochemical failure was calculated and also late toxicities
according Common Toxicity Criteria scale were assessed. Median follow-up
was 5.5 years.
Results: At the time of analysis biochemical control was achieved by 88% of
patients. Biochemical relapse free survival calculated according to KaplanMeier for all patients at 5 and at 9 years’ follow up was 85,7% and 77,2%,
respectively. Analyzing biochemical relapse free survival separately for different boost dose levels, at 5 years it was 97% for the 35Gy boost dose and 82%
for the 25Gy and 30Gy dose levels. The side effects of therapy were negligible - we registered by 18 patients (15%) grade 1/2 rectal proctitis, by 18
patients (15%) grade 1/2 cystitis and by one patient (0.8%) grade 3 proctitis.
No incontinence has been observed.
Conclusions: Image-guided conformal PDR-brachytherapy using 35 Gy as
boost dose after external beam radiation therapy (total dose 85 Gy) is a very
effective treatment option with very low morbidity.
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INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY + IMRT
VS. HDR MONOTHERAPY : MEDIAN 8 YEAR FOLLOW-UP IN 428
PATIENTS
L. Losolla1 , R. Mark1 , R. Akins1 , M. Nair1
1
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, Texas, USA
Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for
prostate cancer using High Dose Rate (HDR) + External Beam Radiation
Therapy (EBRT) technique has been reported with results comparing favorably to surgery, Low Dose Rate (LDR) brachytherapy +/- EBRT, EBRT, and Intensity Modulated Radiation Therapy (IMRT). The role of supplemental EBRTin brachytherapy is controversial. We compare our results of HDR + IMRT vs.
HDR monotherapy.
Materials: Between 1997 and 2010, 428 patients with T1 and T2 localized
prostate underwent TRUS guided interstitial implant. There were no Gleason
Score or PSA exclusions. After discussion of treatment options, 109 patients

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elected HDR Implant + IMRT and 319 patients underwent HDR monotherapy.
No patient received Hormonal Blockade. Median Gleason Score was 7 (range: 4 to 10). Median PSA was 9.8 (0.60 to 39.8). IMRT treatment volume
included the prostate + seminal vesicles + 2 cm margin. Implant treatment
volumes ranged from 32 cm3 to 196 cm3 . In patients who received IMRT +HDR, 4500 cGy in 25 fractions was given via IMRT and 1650 cGy to 2000 cGy
in 3 fractions via HDR. Our protocol for HDR alone, has called for two HDR
Implants. The treatment volume received 2,250 cGy in 3 fractions prescribedto the 100% Isodose line, given over 24 hours. A 2nd implant was performed
4 weeks later, delivering a further 2,250 cGy in 3 fractions, bringing the final
dose to the prostate to 4,500 cGy in 6 fractions. Urethral dose points (12-16)
were followed, and limited to < 105% of the prescription dose.
Results: There was no significant difference between the treatment groups
with respect to T-Stage, Gleason Score, and PSA. With a median follow-up
of 102 months (range : 6 months to 174 months), the overall PSA disease
free survival was 88.0% (377/428). Overall 8 year actuarial PSA Disease
Free Survival (DFS) was 86%. In patients undergoing IMRT + HDR Implant,
PSA disease free survival was 84% vs. 86% for patients undergoing HDR
alone (p=0.73). The 8 year actuarial overall survival was 80% for the group
receiving IMRT + HDR vs. 82% with HDR monotherapy (log rank = 0.5).
The 8 year actuarial PSA DFSs by risk group for patients treated with IMRT+HDR were, 96% for low risk, 84% for intermediate risk, and 69% for high risk.
The corresponding numbers for HDR alone were 94% for low risk, 86% forintermediate risk, and 65% for high risk. Urethral stricture requiring dilatation
has developed in 5.1% (22/428) of patients. Urinary stress incontinence has
occurred in 2.8% (12/428). RTOG late bladder toxicities were : 0% Grade 4,
0% Grade 3, and 2.8% (12/428) Grade 2. RTOG late rectal toxicities were
: 0.5% (2/428) Grade 4, 0% Grade 3, 2.6% (11/428) Grade 2, and 3.0%
(13/428) Grade 1. RTOG rectal toxicity was higher in patients undergoing
HDR + IMRT with 15.6% (17/109) of patients experiencing Grade 2 and 1
symptoms, vs. 2.2% (7/319) receiving HDR alone (p < 0.0001).
Conclusions: With median 8 year follow-up, we have observed no significant difference in PSA disease free survival in patients undergoing HDR
monotherapy vs. HDR + IMRT. Complications were similar, though RTOG
Grade 1 and 2 late toxicity was higher in patients receiving HDR + IMRT.
HDR monotherapy compares favorably to EBRT, LDR +/- EBRT, and HDR +IMRT, both with regard to PSA disease free survival, and complications. With
regard to implant technique, HDR brachytherapy offers other advantages over
LDR, such as no radiation exposure to hospital personnel, no seed migration,
greater dose flexibility and precision of radiation dose delivery. Larger volumes can be treated with HDR. By omitting EBRT, rectal complications may
be reduced.

T UESDAY, M AY 10, 2011
the 4 fraction 2-day procedure as well as with the 2 fraction 1-day implant.
No statistical differences in outcomes were noted. The reduction on BED so
far has not impacted negatively the survival outcomes. Longer f/u is required
particularly for the 1-day regime.
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MODERATE DOSE ESCALATION WITH SINGLE-FRACTION
HIGH-DOSE-RATE BRACHYTHERAPY BOOST FOR CLINICALLYLOCALIZED INTERMEDIATE- AND HIGH-RISK PROSTATE CANCER:
FIVE-YEAR OUTCOME OF THE FIRST 100 CONSECUTIVELYTREATED PATIENTS
P. Agoston1 , T. Major1 , G. Fröhlich1 , Z. Szabó1 , J. Lövey1 , J. Fodor1 , M.
Kásler2 , C. Polgár1
N ATIONAL I NSTITUTE OF O NCOLOGY, Department of Radiation Oncology,
Budapest, Hungary
2
N ATIONAL I NSTITUTE OF O NCOLOGY, -, Budapest, Hungary
1

Purpose: To analyze the clinical outcome and toxicity data of the first 100
consecutive patients treated with a single fraction high-dose-rate brachytherapy (HDR-BT) and external beam radiotherapy (EBRT).
Materials: Two-hundred and eighty patients have been treated with HDR-BT
boost for localized intermediate- to high-risk prostate cancer. Among these,
the outcome and toxicity of the first 100 patients, treated with a single HDRBT fraction were assessed. A median dose of 60 Gy EBRT were given to theprostate and vesicles. Interstitial HDR-BT of 10 Gy was performed during thecourse of EBRT.
Results: Median follow-up time was 61.5 months. The 5-year actuarial rate ofoverall survival, cause-specific survival, disease-free survival, and biochemical no evidence of disease (bNED) for the entire cohort was 93.3%, 99.0%,
89.3%, and 85.5%, respectively. The 7-year actuarial rate of bNED was
84.2% for the intermediate- and 81.6% for the high-risk group (p=0.8464).
The 7-year actuarial rate of bNED for grade 1, 2, and 3 tumors was 97.5%,
80.0%, and 67.1%, respectively. The 5-year probability for developing lategrade 3 gastrointestinal (GI) and genitourinary (GU) toxicity was 2.1% and14.4%, respectively. Grade 3 GU complications occurred significantly more
frequently in patients with a history of pre-irradiation transurethral resection(29.1% vs. 8.8%; p=0.0047).
Conclusions: Five-year outcome after 60 Gy EBRT plus a single fraction of
10 Gy HDR-BT boost are encouraging. Pre-radiation transurethral resection
significantly increases the risk of late severe GU complications.

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CLINICAL OUTCOMES COMPARISON FOR PROSTATE CANCERPATIENTS WITH LOW/INTERMEDIATE RISK FACTORS TREATEDSEQUENTIALLY WITH 2 HIGH DOSE RATE BRACHYTHERAPYSCHEDULES
A. Martinez1 , M. Ghilezan1 , H. Ye1 , P. Chen1 , D. Krauss1 , J. Dilworth1 , M.
Wallace1 , G. Gustafson1
1
W ILLIAM B EAUMONT H OSPITAL, Radiation Oncology, Royal Oak, USA
Purpose: During the last decade, we have seen a large increase in the useof low dose rate (LDR) and high dose rate (HDR) brachytherapy treatments
as monotherapy for prostate cancer patients with low and intermediate risk
factors. We are reporting the outcomes of two HDR dose schedules.
Materials: From 3-1999 to 4-2010, 382 patients have been treated with HDR
monotherapy in two sequential trials. For the first group, 311 patients weretreated with 950 cGy x 4 fractions delivered to the prostate PTV as determined by TRUS with a minimum of 6 hr in between fractions over two days.
The other 71 patients received 1200 cGy x 2 with a 6 hr split in 1-day. All patients were treated using TRUS-based real-time intraoperative inverse planning. Dosimetric goals: prostate V100 >95%, V125<60%, V150<30%, urethra V100<90%,V115<3%, rectum V75<1%. The biological equivalent doseusing and α/f 1.5 was 266 for the 2-day and 208 for the 1-day.
Results: The mean values for: f/u for all patients was 3.9 yr (0.6-11.3), for the
2-day group was 4.2 yr (0.6-11.3) and for the 1-day 2.2 yr (0.8-3.4), age 63(40-83), pretreatment PSA 5.3. No difference in T-staging but more Gleason 7(40% Vs 21%) for the 1-day regime. At 3 years, the Phoenix BC was 90% and95%, local recurrence 0.5% and 0%, clinical failures 0.5% and 0%, disease
free survival 98.5% and 98.3%, distant metastasis 0% and 0%, cause specificsurvival 100% and 100% and overall survival 99% and 98.3% respectively forthe 2-day versus the 1-day schedule. None of these values were statistically different. Acute and chronic toxicity was assessed using the NCI CTAE
version 3.0. There were no statistical differences in either acute or chronic
toxicity for the genitourinary and/or gastrointestinal tract. GU Chronic grade
1 toxicity for frequency/urgency was 18.6%, difficulty with urination 5.1%, incontinence 3.3% , hematuria 1.5% and urethral stricture 0.6%. For grade 2
toxicities, frequency/urgency 4.2%, dysuria 1.8% and urethral stricture 0.6%.
For grade 3 toxicities, dysuria 0.6%, difficulty with urination 0.6% and urethralstricture 1.3%. For chronic GI, grade 1 diarrhea 1.8%, proctitis 0.3%, andrectal tenesmus 0.6%. For grade 2 toxicities, diarrhea 0.3%, rectal bleeding
0.3%, and Proctitis 0.3%. No grade 3 or 4 complications were seen.
Conclusions: Excellent survival and toxicity outcomes were obtained with

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IS SINGLE FRACTION 15 GY THE PREFERRED BOOST DOSE FORPROSTATE CANCER?
G. Morton1 2 , A. Loblaw1 , H. Chung1 , R. Sankreacha3 , N. Law4 , L. Zhang5 ,A. Deabreu6
1
S UNNYBROOK O DETTE C ANCER C ENTRE, Radiation Oncology, Toronto,
Canada2
U NIVERSITY OF TORONTO, Radiation Oncology, Toronto, Canada
3
C ARLO F IDANI P EEL R EGIONAL C ANCER C ENTRE, Medical Physics,
Mississauga, Canada
4
S UNNYBROOK O DETTE C ANCER C ENTRE, Radiation Therapy, Toronto,
Canada5
S UNNYBROOK O DETTE C ANCER C ENTRE, Statistics, Toronto, Canada
6
S UNNYBROOK O DETTE C ANCER C ENTRE, Clinical Trials Unit, Toronto,
CanadaPurpose: High dose-rate (HDR) brachytherapy for prostate cancer is mostcommonly delivered as two or more fractions combined with external beam
radiotherapy (EBRT) over 4 to 5 weeks. Our objective is to provide longer
term results of a phase II clinical trial using HDR as a single fraction of 15 Gy
combined with EBRT over 3 weeks.
Materials: Eligible patients had intermediate risk T1 or T2 carcinoma of theprostate with a PSA < 20 ng/ml and Gleason score of 7 or less, with no androgen deprivation therapy and prostate < 60 cc. We accrued 125 patients witha median PSA of 6.8 ng/ml (2.0-18.6) and median volume of 31 cc (14-59cc);
93% had Gleason 7. HDR brachytherapy was first given as a single fractionof 15 Gy to the entire prostate, using CT planning. After a 2-week break, 37.5
Gy in 15 fractions was delivered to the prostate and base of seminal vesicles
using a 3D conformal EBRT technique. Median prostate V100 was 97%, median V200 10.7%, median dose to 10% of urethra (D10) 120%, and medianrectal V80 0.8 cc. Patients were followed for toxicity (CTCAE v 3.0), healthrelated quality of life (EPIC), urinary symptoms (IPSS), and clinical and biochemical control. A clinically significant decrease in an EPIC domain score
was considered to be a decrease of one standard deviation of baseline values
in that domain.
Results: With a median follow-up of 3.5 years (range: 1-5 years), one patient
relapsed locally with a rising PSA and underwent salvage prostatectomy. Median PSA at 3 years is 0.2 ng/ml. Only 1 of 38 biopsies at 2 years had persistent cancer. Two patients (1.6%) developed acute Grade 3 urinary toxicity,and median IPSS score returned to within 2 points of baseline by 3 months.

T UESDAY, M AY 10, 2011
No late Grade 3 rectal or urinary toxicity has occurred. Mean EPIC urinary
and bowel domain scores decreased in the first 2 years, and returned to within
5 points of baseline at 3 and 4 years. Mean sexual function scores declined
over the first 4 years although sexual bother scores had returned to baseline
at 3 years. On multivariate analysis, baseline IPSS score (p=0.0125), V100
(p=0.0002) and V200 (p=0.0141) were associated with acute Grade 2 urinary
toxicity, but not with late toxicity. Decline in EPIC urinary quality of life domain
was independently associated with urethra D10 (p=0.0168), with an optimal
threshold cut-point of 120%. Decline in sexual domain scores was associated with smaller prostate volume and high baseline erectile functioning. No
associations were found with declining bowel domain scores. Disease control
and toxicity rates were no different from a historical cohort treated with two
fractions of 10 Gy and 45 Gy EBRT in 25 fractions.
Conclusions: Single fraction 15 Gy HDR combined with hypofractionatedexternal beam radiotherapy is a well tolerated and highly effective treatment
for intermediate risk prostate cancer. Limiting urethra D10 may further reduce
impact of treatment on urinary quality of life.

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Symposium
ESTRO-ESTS-ERS Joint symposium: Lung Cancer - Vision for the future: What ‘we’ will ask forin the new grant applications? - Translational research / High technology
232 speaker
PET IMAGING FOR DOSE ESCALATION IN NON-SMALL CELL LUNGCANCER
D. De Ruysscher1 , W. van Elmpt1 , M. Öllers1 , P. Lambin1
1

MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS -TRICHT, Radiation Oncology, Maastricht, Netherlands

Radioresistant tumours do not exist. Any known malignancy can be cured,
whatever its size or molecular characteristics, when the radiation dose is highenough and is delivered in a reasonably short overall treatment time of at
maximum 7 weeks.
The problem to be tackled is therefore the dose to the organs at risk (OAR),
for they limit the radiation dose that actually can be delivered.
A straightforward way to lower OAR doses is to decrease the size of the irradiated volume, which can be accomplished by introducing the best available
imaging modalities for tumour definition. Our group has pioneered the useof FDG-PET-CT scans in the selective treatment of mediastinal lymph nodes
and has shown lower radiation doses to OAR without hampering local tumour
control rates (De Ruysscher et al. Int J Radiat Oncol Biol Phys 2005).
With the advent of physical, clinical and biological parameters that correlatewith toxicity (Dehing et al. Radiother Oncol 2009, Int J Radiat Oncol Biol
Phys 2009, 2010; see also www.predictcancer.org), we have developed individualised radiation schedules that allow the delivery of high (biologically)
radiotherapy dose levels with even less than anticipated side effects, leading
to encouraging survival rates even in patients traditionally deemed being incurable (van Baardwijk et al. Int J Radiat Oncol Biol Phys 2008; J Clin Oncol2010).
It has been recognized that a malignant tumour is not a homogeneous mass,
but composed of regions that differ in tumour cell density, normal tissue involvement, vasculature, hypoxia and gene expression. As a consequence,delivering equal doses to all parts of the tumour leads to a too low dose to themost resistant parts of the tumour and at the same time to overkill in otherareas. Our group has shown that it is possible to determine on the basisof a single pre-treatment FDG-PET-CT scan the parts of the tumour that areresistant to the currently used chemo-radiation treatments (Aerts et al. Int J
Radiat Oncol Biol Phys 2008; Radiother Oncol 2009; Petit et al. RadiotherOncol 2009; Velazquez et al. Acta Oncol 2010). In an ongoing randomised
phase II trial, which was set-up together with the Netherlands cancer Institute, these regions are selectively boosted with higher radiation doses, whilst
keeping the radiation to the OAR and dose to other target areas to current
standards.
We have also been able to identify heterogeneous radiosensitivity within thenormal lung tissue on the basis of FDG-PET-CT scans, making further individualised therapy possible (Petit et al. Int J Radiat Oncol Biol Phys 2010).
Finally, drugs labelled with PET-tracers show heterogeneous uptake in thetumour, which opens a new era of clinical research (Aerts et al. J Nucl Med2009) that includes combing all this in a "voxel-based radiotherapy"-concept(Lambin et al. Radiother Oncol 2010).
233 speaker
PROTONS COMPARED TO X-IMRT COMPARED TO 3D IN LOCALLYADVANCED NSCLC
R. Komaki1 , X. Wei1 , P. K. Allen1 , R. Amos2 , R. Mohan3 , J. Y. Chang1 , Z.
Liao4 , L. Dong3 , J. D. Cox1
1
MD A NDERSON C ANCER C ENTER, Department of Radiation Oncology,
Houston, USA
2
U.T. M.D. A NDERSON C ANCER C ENTER, Department of Radiation Physics,
Houston, USA
3
MD A NDERSON C ANCER C ENTER, Department of Radiation Physics,
Houston, USA
4
U.T. M.D. A NDERSON C ANCER C ENTER, Department of Radiation
Oncology, Houston, TX, USA
Background: The standard of care for patients with locally advanced nonsmall cell lung cancer with good performance status is concurrent chemotherapy and radiation therapy (RT). The superiority of this approach was demonstrated in a series of randomized trials in the era of 2-dimensional (2D) RT.
However, patients treated with concurrent RT and chemotherapy are at risk of
toxic effects such as severe esophagitis, pneumonitis, and bone marrow toxicity that can lead to delayed or missed treatments or hospitalizations, resulting
in both lesser treatment efficacy and greater medical costs. We showed thatusing 3D conformal (X-ray) RT (CRT) can cut the risk of severe esophagitis in half relative to 2D RT. We also showed that use of intensity-modulated(X-ray) RT (X-IMRT) can further reduce the risk of treatment-related pneu-

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monitis, but not that of esophagitis, relative to 3D CRT. Hypothesizing that thephysical dose characteristics of protons will allow proton beam therapy (PBT)
to spare critical structures such as esophagus, lung, and bone marrow fromincidental irradiation to a greater extent than X-ray therapy, we evaluated therates of severe esophagitis, pneumonitis, and bone marrow suppression inpatients with locally advanced NSCLC treated with concurrent chemotherapy
with either PBT or X-IMRT.
Methods: From January 2003 to June 2008, 128 patients with locallyadvanced NSCLC were treated with chemotherapy+PBT (62 patients) or
chemotherapy+X-IMRT (66 patients); all had concurrent chemotherapy, none
had had prior thoracic RT, and all were treated to at least 60 Gy (for X-IMRT)
or 60 CGE (60 cobalt-Gy-equivalent) (for protons). Patients who had both
IMRT and 3D CRT or PBT were excluded. Toxicity was graded according
to the Common Terminology Criteria for Adverse Events version 3.0.
Results: The median follow-up times for the PBT group and the X-IMRT
group were 15.2 months (range, 3.125.7 months) and 17.4 months (range,
1.437.6 months), respectively. Median patient age was 67 years (PBT) and62 years (X-IMRT) (P<0.04); Karnofsky performance scores for both groups
were 80. Nodal involvement was slightly more common in the X-IMRT group(91%) than in the PBT group (81%) (P>0.05). Median dose was 74 CGE(range, 63-80.5 CGE) for the PBT group vs. 63 Gy (range, 60-76 Gy) for
the X-IMRT group (P<0.001). Patients treated with PBT experienced significantly smaller reductions in hemoglobin (P<0.001), neutrophils (P<0.008),
lymphocytes (P<0.001), and white blood cells (P <0.001) compared withthose treated with X-IMRT. No significant differences were found between
groups in platelet counts. Severe (grade 3+) esophagitis occurred in 44% of
patients treated with X-IMRT vs. 5% with PBT. Severe (grade 3+) treatmentrelated pneumonitis was observed in 9% of the X-IMRT group vs. 2% of the
PBT group.
Conclusions: Our preliminary analysis of patients with locally advanced NSCLC suggests that treatment with concurrent chemotherapy+PBT
leads to less bone marrow toxicity than does treatment with concurrent
chemotherapy+X-IMRT, which could allow the use of more aggressive systemic regimens for such patients. This supposition needs to be tested
prospectively in a randomized trial. The considerable reduction in esophageal
reactions after PBT is consistent with the predicted sparing of normal tissues.
The ongoing reductions in severe treatment-related pneumonitis (from 32%
after 3D CRT to 9% after X-IMRT to 2% after PBT) are consistent with theability of advanced technologies to spare normal lung. These findings have
led to the development of a prospective randomized comparative trial of PBTvs. X-IMRT (funded by the U.S. National Cancer Institute) conducted jointly at
MD Anderson and Massachusetts General Hospital. Both arms of the study
will involve high-dose radiation (66 to 74 Gy/CGE) with concurrent carboplatin
and paclitaxel chemotherapy. The endpoints are local tumor control and severe treatment-related pneumonitis. Tumor motion is being accounted for byusing 4D CT simulation to develop internal target volumes for use with breathhold or gating techniques. Future developments in PBT such as discrete spot
scanning and intensity-modulated proton therapy must await resolution of tumor motion issues when these advanced techniques are to be used for protondelivery.
234 speaker
BIOLOGICAL PREDICTION FOR MOLECULAR TARGETING IN
RADIOTHERAPY OF NSCLC
M. Baumann1
1
M EDIZINISCHE FAKULTÄT C ARL G USTAV C ARUS T ECHNISCHE U NIVERSITÄT
D RESDEN, Radiation Oncology, Dresden, Germany
Background: Molecular targeting is widely considered a promising strategy
to improve the still poor outcome of radiotherapy in locally advanced NSCLC.
However novel molecular drugs are not without toxicity and often expensive.
Furthermore there is good reason to believe that many of these drugs, because of their relatively specific mode of action, will be of benefit only for asubsets of patients. Thus there is considerable need to address the use of
biomarkers for molecular targeting combined with radiotherapy in NSCLC.
Methods: Review of preclinical and clinical data taking into consideration the
different current modes of failure of NSCLC after radiotherapy and so calledclassical predictors of local control after radiation therapy.
Results and Conclusions: A rapidly growing number of new drugs with relatively high specificity becomes available every year for clinical testing and an
even larger number of novel compounds is in preclinical research pipelines.
This fact alone urgently calls for the development of biomarkers for the useof the drugs for well stratified groups of patients in the specific clinical context. Unfortunately current efforts are almost exclusively directed toward development of biomarkers for use of the new drugs given alone or combinedwith established chemotherapeutic regimens. This is of major concern as
several preclinical investigations have shown that novel drugs which achieveremission and growth delay do not necessarily improve local tumor control
when combined with radiation. This makes it likely that study endpoints andbiomarkers which are valid in the context of systemic therapy may not be necessarily relevant for enhancing the curative potential of radiotherapy which
depends in a dose-dependent manner on inactivation of cancer stem cells.
Another problem is that in clinical practice several well established parameters affect the chance to obtain permanent local control after radiotherapy,

T UESDAY, M AY 10, 2011
including radiation dose and dose-distribution, number of cancer stem cells
as reflected by tumor volume, repopulation of CSC as reflected by the impact of overall treatment time on local control and aspects of the microenvironment. All these classical biological parameters are confounders which
may importantly limit the usefulness of studies aiming to assess tumor-tissue
based molecular biomarkers predicting outcome of therapy. It therefore does
not come as a big surprise that the current data base for tumor tissue based
biomarkers for molecular targeting in radiotherapy is extremely slim. In thecontext of a multidisciplinary session on visions for novel future research approaches it appears important to stress that specific biomarker research in thecontext of radiotherapy is needed, that this research should be preclinicallyand clinically integrated very early in the translational research chain and not
only after a new drug biomarker couplet has already hit the market without radiotherapy, that in clinical studies patients must be extremely well stratified forthe important prognosticators and predictors known today (including generaluse of multivariate methodologies) and that very high quality of radiotherapy
and treatment monitoring is prerequisite for such investigations.

Breast cancer - Vision for the future: What ‘we’
will ask for in the new grant applications? - Translational research / High technology

T UESDAY, M AY 10, 2011breast cancer followed by radiotherapy were analyzed with regards to fatigue(n=249) in relation to a possible influence from clinical factors as well as theassociation between mRNA expression levels in blood and the developmentof fatigue (n= 329) and fibrosis (n=254).
References:1. Helland A et al., Radiother Oncol. 2006 Aug;80(2):230-5.
PMID: 16890317
2. Rdningern OK et al., Radiother Oncol. 2008 Mar;86(3):314-20. 2007
PMID: 17963910
3. Alsner J et al., Radiother Oncol. 2007 Jun;83(3):261-6. PMID: 17512072
4. Landmark-Hyvik et al., Int J Radiat Oncol Biol Phys. 2011 Mar 1;79(3):87583. 2010 PMID: 21129856
5. Reinertsen KV et al., J Cancer Surviv. 2010 Dec;4(4):405-14. 2010 PMID:
20862614
6. Landmark-Hyvik et al., Pharmacogenomics J. 2009 Oct;9(5):333-40. 2009
PMID: 19546881
236 speaker
PARTIAL BREAST RADIOTHERAPY: WHAT DO WE NEED TO
KNOW?
J. R. Yarnold1
1
T HE I NSTITUTE OF C ANCER R ESEARCH AND R OYAL M ARSDEN H OSPITALNHS F OUNDATION T RUST, Academic Unit of Radiotherapy, London, United
Kingdom

235 speaker
THE GENETIC AND EPIGENETIC INFLUENCE ON RADIATIONRESPONSE
A. L. Børresen-Dale1 , H. Edvardsen2 , H. Landmark-Hoyvik1 , A. R.
Halvorsen1 , Helland1 , S. D. Fosså1 , V. Kristensen1
1
DNR - N ORWEGIAN R ADIUM H OSPITAL, Oslo, Norway
2
R IKSHOSPITALET-R ADIUMHOSPITALET M EDICAL C ENTER, Oslo, Norway
Due to extensive mammographic screening programs, there is now a shift
towards earlier detection of breast cancer in the Western world. As a consequence, many breast cancer patients in this region will only receive locoregional therapy in which radiation treatment plays a central role. Large variations both in the effect of treatment and development of side-effects are seenfrom a clinical viewpoint. However, little is known about the biological background for these effects although we know that treatment related factors suchas dose, fractionation pattern and irradiated volume play a role. To increase
our understanding of the molecular biology resulting in a given tumour response or the development of a late adverse effect in the normal tissue weneed to explore both the genetic variability and the epigenetic contribution tothese end-points.
By studying genetic variation as well alterations in mRNA expression andDNA methylation patterns caused by the radiation treatment in multiple
sources (tumour tissue extracted before and after therapy, fibroblast cell lines,
blood cells) from both breast cancer patients and survivors we hope to be able
to shed light on the underlying molecular mechanisms of a given tumour response or the development of side effects such as fibrosis and fatigue. So far
we have studied in vivo radiation-induced changes in intratumoral mRNA expression levels in biopsies taken before and after neo-adjuvant radiotherapy.
Our goal is to unravel the underlying biology behind tissue effects of radiation
identifying genes involved in cell cycle regulation and DNA repair induced byradiotherapy (1). Studying mRNA gene expression alterations in irradiatedfibroblast cell lines we could identify an expression profile of a minimum of
18 genes associated with risk of radiation induced fibrosis. The identified
genes were related to known biological processes such as apoptosis, extracellular matrix remodeling/cell adhesion, proliferation and ROS scavenging(2,3). A link between this expression profile and genetic variation (SNPs)
in genes involved in, among others IL8 signaling and mitochondrial dysfunction, were also identified. We have shown that BC survivors with radiationinduced fibrosis have a down-regulation of most of the core genes in the TGF
signaling pathway (4) and that radiation induced fibrosis is associated withgenetic variation (SNPs) in proteins involved in metabolizing reactive oxygen
species. Focusing on the development of chronic fatigue in the same cohort of BC survivors we identified an association between chronic fatigue andpsychological distress, treatment-area related discomfort, BMI ≥ 30, CRP as
well as a higher level of leucocytes, lymphocytes and neutrophiles compared
to non-fatigued BC survivors (5). We could also show that gene sets involvedin plasma- and B-cell pathways differed between the chronic fatigued and thenon-fatigued survivors (6).
Material" In vivo radiation study: Biopsies were extracted before and after neoadjuvant radiotherapy treatment (10 treatments (of 2 Gray (Gy) each) from19 breast cancer. Gene expression microarray analyses were performed using Agilent Human 1A oligo microarrays to identify in vivo radiation-responsive
genes in tumours.
" Fibroblast cell lines: Fibroblast cell lines from 31 individuals with variablerisk of radiation induced fibrosis were analyzed with regards to transcriptional
differences in basal and radiation-induced gene expression profiles using 15K
cDNA microarrays.
" Cancer survivor study: Subsets of a cohort of 403 breast cancer survivors having previously undergone curatively intended surgery for stage II/III

The rationale for partial breast radiotherapy (PBRT) rests on the following
assumptions: i) the majority of ipsilateral local relapses (LR) within the first
5 years after breast conservation surgery with or without whole breast radiotherapy (WBRT) present in the vicinity of the primary tumour, and mostof these are true recurrences (TR) preventable by PBRT, ii) the minority ofLR presenting elsewhere in the breast tend to appear after 5 years and aremostly new primaries (NP), which are not preventable by radiotherapy and iii)PBRT causes fewer late adverse effects (AE) than WBRT. The prediction isthat rates of LR will be comparable after PBRT and WBRT, with significantly
lower rates of late AE after the former.
Seven randomized trials testing PBRT, 3 of which are in follow up phase, will
provide outcome data on 15,000 women over the next decade. Metanalysis will provide an estimate of overall effectiveness, and if all trials generate
similar results, interpretation is likely to be straightforward. Metanalysis ofsubgroups is likely, for example, to identify women for whom PBRT is unsuitable, but major inter-trial differences in radiotherapy technique and doseschedule will prevent more precise conclusions relating to important treatment variables, including optimization of CTV and dose intensity. At worst, the
PBRT field will resemble a battle between competing technologies validated
in pragmatic trials and failing to achieve common agreement on optimal CTV
and dose intensity. Competing new technologies will often be the products oftranslational research in the physics lab, but this will not be considered here.
So, what do we want to know about PBRT, why do we want to know it, andare we likely to find it out?
A fundamental question is; "what is the optimal clinical treatment volume(CTV) for PBRT?" CTV may be the single most important determinant of clinical benefit, but its impact on LR and AE will not be straightforward to identify
from 6/7 PBRT trials, which vary dose as well as volume in the experimental
arms. The current PBRT trials will not generate dose response data either,
due to confounding by volume and by profound differences in fractionation,
ranging from a single intraoperative fraction to twice daily and once daily regimens. The next round of grant application is unlikely to address these issues in a systematic way. A future research proposal might compare different
PBRT technologies head to head, but it is perhaps more likely that a range of
PBRT techniques compare PBRT to no RT in low risk populations.
Whatever the clinical protocol, future protocols should consider accurate spatial mapping of LR in relation to the treatment volume, requiring CT scanningin the original PBRT treatment position before further surgery is performed.
If an excess of LR is recorded after PBRT, it will be relevant to understandtheir clonal relationships to the primary tumour as well as their location in or
outside the treatment volume. Sources of LR include residual foci of invasive primary tumour, lymphovascular emboli and NP. Molecular analyses will
help shed light on the clonal relationships between TR and NP, although thedistinction at a genetic level may not be clear. This might be the case if aphenotypic NP develops from pre-existing DCIS sharing much of its genetic
history with the original tumour. The contribution of lymphovascular emboli to
LR can probably only be inferred in multivariate analysis by association between LR and axillary node status at presentation. The relative and absolute
frequencies and locations of each category of LR should help refine patient
selection and treatment variables.
Associated translational studies will test other hypotheses relevant to PBRT.
For example, there is a suggestion that PBRT works by down regulating
wound healing cytokines that otherwise stimulate tumour regrowth and LR
in the early postoperative period. If confirmed as a significant component oftherapeutic effect, the challenge will be to identify which wound healing cytokines are important, which tumours are responsive to them and what the
implications are for CTV.
Another area on investigation may be the trade-off between a (slightly) higher
rate of ipsilateral LR after PBRT and a lower risk of contralateral NP, representing a potential trade-off between non-stochastic and stochastic effects.

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Grant applications will also nclude correlative research relevant to WBRT as
well as PBRT, chief of which must include investigation of predictive biomarkers of late AE and tumour response.
237 speaker
INTERACTION WITH SYSTEMIC THERAPY
A. Fourquet
Abstract not received.

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drift tube and the conical surface models, but reduced for the smaller cathodemodels; 1.67, 0.97 and 2.2mm for the 1.7mm radius cathode, 1mm radius
cathode and the original model respectively at 0.12T.

Physics Proffered papers 5: Strategy and Developments in IGRT
238 oral
INCLUSION OF CONE BEAM COMPUTED TOMOGRAPHY DOSE IN
THE OPTIMIZATION OF A TREATMENT PLAN
J. Stenbeck1 , H. Alkhatib1 2 , K. Bzdusek3 , W. Neglia1 , D. Tedeschi2 1 , B.
Wright1
1
S OUTH C AROLINA O NCOLOGY A SSOC., Columbia, USA
2
U NIVERSITY OF S OUTH C AROLINA, Columbia, USA
3
P HILIPS R ADIATION O NCOLOGY S YSTEMS, Madison, USA
Purpose: The utilization of cone beam computed tomography (CBCT) increases the accuracy of patient alignment and tumor localization; at the sametime, there is an undesirable dose to critical structures that should be avoided.
Therefore, optimization of the CBCT in the treatment planning system is theappropriate step to account for that dose. Typically, treatment planning systems (TPS) do not possess the capability to model photon beams at the low
energies used by CBCT (<150 kVp). However, by introducing monoenergetic
energy deposition kernels into the TPS from 20 to 110 keV, it is possible tocome up with a spectrum to model a diagnostic energy beam. The purposeof this study is to demonstrate how it is possible to model the CBCT treatment
onto a patient to estimate the dose they will receive.
Materials: An Elekta Synergy LINAC equipped with X-ray Volume Imaging(XVI), Elekta’s version of CBCT, was used in this study. Depth dose curves
were measured in a water tank along the central axis of three CBCT collimators used in patient scans; additionally, transverse and radial profiles were
scanned at depths of 1, 5, and 10 cm for each collimator. TG-61 was performed to come up with a cGy/MU value and to get the correct output factors.
Philips Pinnacle Beta was used as the TPS and monoenergetic energy deposition kernels from 20 to 110 keV were added. An energy spectrum wascreated to match the depth dose and profile scans for each collimator for abeam with 120 kVp, 40 mAs, and 10 ms/frame. Film, TLD, and ion chamber (with ADCL calibration for diagnostic energy levels) measurements wereused to verify the model in a simple geometry of a cube of solid water at 90
SSD with an AP beam. Additionally, a Pinnacle CBCT plan was created foran anthropomorphic phantom that used the parameters of a pelvis protocol.
The phantom was loaded with 93 TLDs throughout the area irradiated which
provided a measured dose to compare with the calculated dose in a complex
geometry.
Results: The relative dose readings from the TPS on the solid water matched
the film profiles in the transverse and radial directions. Additionally, an absolute dose was measured to be 7.18 ± 0.12 cGy verses 7.3 cGy in Pinnacle’s
calculation at a depth of 1 cm in the solid water. The noise on the ion chambers is large at depths of 5 cm and 10 cm. However, with multiple scans
and longer dwell times the noise was minimized. This was done by checking
that the averaged and then smoothed data fell within the standard deviationof the raw data, which was then used as the profile to model in the TPS(see Figure 1). The TLD results in the anthropomorphic phantom show thatthe dose in areas of minimal heterogeneities can be accurately predicted.
However, corrections are needed for points in and around bony structures toaccurately account for the low energy photon interactions. Additionally, a half
CBCT scan (180 degrees + fan angle) was modeled and measured, whichshowed regions where the dose reduction was up to 90% while still allowing
for adequate alignment of the anthropomorphic phantom.

Figure 1: The depth dose, transverse, and radial profiles with the measured
and modeled data being the solid and dashed lines, respectively. The modeled beam is specific for the collimator and parameters used in pelvis CBCT
protocols.
Conclusions: The results show that a diagnostic beam modeled in the TPS
calculates the dose a patient will receive from CBCT. Heterogeneity corrections are needed to more accurately calculate the dose in and around bony
anatomy. Additionally, this study is being expanded to the Oncentra TPS tocompare accuracy of dose estimations for CBCT with other algorithms.
239 oral
GEOMETRIC ADAPTATIONS TO AN ELECTRON GUN DESIGN FOR
USE IN AN IN-LINE MRI-LINAC
L. C. Holloway1 23 , D. Constantin4 , P. Keall5 , R. Fahrig4
1
L IVERPOOL AND M ACARTHUR C ANCER T HERAPY C ENTRES, Sydney,
Australia
2
I NSTITUTE OF M EDICAL P HYSICS , U NIVERSITY OF S YDNEY, Sydney,
Australia
3
C ENTRE FOR M EDICAL R ADIATION P HYSICS , U NIVERSITY OF W OLLON GONG , Wollongong, Australia
4
S TANFORD U NIVERSITY, Department of Radiology, Stanford, USA
5
U NIVERSITY OF S YDNEY, Sydney, Australia

Purpose: A number of groups are investigating the development of combined
Magnetic Resonance Imaging scanners and linear accelerators (MRI-linacs).
This development will provide high quality soft tissue imaging during radiotherapy delivery allowing for real time adaptive radiotherapy. Our group isinvestigating the possibility of an in-line design where the magnetic field runs
parallel with the radiation beam direction. In this environment we have previously shown that although with reduced current the electron gun can still
operate, if not optimally, without shielding. This work has investigated some
simple design modifications to determine if these modifications can result inan electron gun which operates optimally within a parallel magnetic field as
will be required for our MRI-linac design.
Materials: An initial electron gun model was developed using Opera/Scalasoftware based on modelling work from St Aubin et al. Med Phys 2010. Operation of this electron gun was simulated within an in line magnetic environment with field strength ranging from 0 to 0.18T (the likely upper bound of our
MRI-linac design). Baseline current and emittance values were determined
for the resulting beam at the exit from the anode and the beam radius was determined at the entrance to the anode. The gun model was then adapted fortwo smaller cathode sizes (1.7 and 1mm radius), two larger anode drift tube
sizes (1.25 and 2.2mm radius) and two conical cathode surfaces (cone angle
172 and 150 degrees). For each of these model adaptations Opera/Scalawas used to model the resulting beam for the same magnetic fields as theinitial model.
Results: The model with the lowest emittance was the conical cathode surface with a 150degree cone angle. Emittance generally increased with increase in the anode drift tube size, decreased with the conical surface andremained constant with the change in cathode size compared to the original model across the magnetic field range(Figure one). The model withthe largest current was the anode drift tube with 2.2mm radius. However,at higher field strengths this current was still below the current achieved by
the initial model with zero field; 0.25A as compared to 0.30A. The beam radius on entering the anode was approximately constant for the larger anode

Conclusions: Basic geometrical adaptations to a Pierce type electron gun
model for use in a in-line magnetic field can improve the beam current or
emittance compared with an initial model. However in these initial investigations we have not been able to simultaneously increase the current andreduce the emittance. Thus more major adaptations to electron gun design
may be required for optimal use within a parallel magnetic field.
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DISTORTION FREE MR IMAGES FOR IGRT ON THE MRIACCELERATOR
S. Crijns1 , B. Raaymakers1 , J. Lagendijk1
1

U.M.C. U TRECHT, Department of Radiotherapy, Utrecht, Netherlands

Purpose: In MR-guided interventions, it is desirable to establish a solid relationship between the imaging coordinate system and world coordinates. Thisis particularly important in IGRT with an MRI-accelerator, as radiation cannot
be visualized in MR images. In general, there are discrepancies between
the coordinate systems. When the conventional frequency encoding is used,diffusion, field inhomogeneities, chemical shift, etc., manifest themselves as
image distortions. We propose here to deal with these effects by using phase
encoding in all directions. We demonstrate the effectiveness of this approachfor several cases.
Materials: Experiments are perfomed on a 1.5T whole body Achieva scanner (Philips Medical Systems, Best, The Netherlands). Spin echo (SE) images are acquired with FOV 128x128 mm2, acquisition matrix 128x128 pixels,
TE/TR 30/150 ms, acquisition time 20 s. Purely phase encoded images are
acquired with the same FOV, acquisition matrix 64x64 pixels, TE/TR 30/150
ms, acquisition time 6.1 min. Images are acquired of two phantoms using aquadrature head coil. Phantom I is a cylinder filled with copper-sulfate doped
water. Phantom II is a co-axial glass cylinder, where the inner cylinder isfilled with a) air and b) sunflower oil and the outer cylinder with copper sulfate
doped water. The phantoms are positioned in the geometrical center of thescanner, with the cylinder axis perpendicular to the magnetic field.
Results: Figure 1 shows SE reference images (A-D) and corresponding
phase encoding images (E-H) of phantom I and II. A and E are images where
the resonance frequency is determined by the scanner and no field inhomogeneities are present. A 500 Hz offset is applied to the resonance frequency
and the acquisition is repeated. The SE image (B) shows the translationthat is to be expected (relative to the scanner center which is denoted bya cross), whereas the purely phase encoded image (F) is unaffected. The
air/water transition in phantom II creates a field inhomogeneity that produces
image distortions as can be seen in C. Finally, in a SE image of phantom
IIb (D) we see distortions and a chemical shift artifact. The two artifacts arecompletely absent when using only phase encoding (G/H), although all four
images (C,D,G,H) are acquired with the same small read-out gradient to exaggerate the distortions.

Conclusions: The pure phase encoding acquisition method can be used
to avoid image distortions related to spatially varying resonance frequency.
Preliminary results indicate that the inherently long acquisition time can be reduced by a combination of sensitivity encoding, compressive sensing and fastacquisitions like SPRITE, but the method is already applicable to calibration
procedures in its current form. This makes purely phase encoded acquisitiona valuable tool in applications that require high geometrical accuracy.
241 oral
A NOVEL APPROACH TO LINAC-MOUNTED INTRA-FRACTIONAL
X-RAY IMAGING FOR MOTION MANAGEMENT
M. Fast1 , U. Oelfke1 , S. Nill1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Division of Medical
Physics in Radiation Oncology, Heidelberg, Germany
Purpose: In modern IGRT treatments, a number of imaging techniques suchas CBCT have helped to reduce the impact of inter-fractional motion. Although highly conformal dose distributions are routinely used to irradiate patients, the effect of intra-fractional motion is still largely unaccounted for. In
order to manage intra-fractional motion efficiently, we have developed an xray imaging framework, which can monitor the target location in respect to thetreatment field over the course of a treatment fraction either continuously or
on demand. Due to the unique in-line geometry of our x-ray imaging equipment, this system is capable of tracking tumour and organ motion perpendicular to the treatment beam, the direction that usually features steep dose
gradients.
Materials: The experimental setup was implemented on a research Siemens
Artiste linear accelerator, equipped with an additional 41x41 cm2 amorphousS 94

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silicon flat-panel detector (FPD) mounted underneath the treatment head.
The in-line geometry allows kV (imaging) and MV (treatment) beams to share
two closely aligned beam axes (see figure). The kV x-ray source, usuallymounted directly across from the flat-panel imager, was retracted towards
the gantry by about 13 cm to geometrically separate the MV treatment field
and kV image on the detector. This step is necessary in order to maximise
the quality of the kV image information. Because the MV signal outnumbers
the kV signal by a factor of 50 for the central region of the detector, two consecutive frames (the first MV-only and the second with kV and MV signals)
were subtracted to generate a kV-only image. The kV images were thenanalysed with an automated threshold-based marker detection algorithm andthe position information sent to the DKFZ tracking tool to allow for adequate
interventions.

T UESDAY, M AY 10, 2011
and OAR contoured on CT, and ii) for the actual HR CTV and OAR delineatedon MR images of this application.
Results: When MR-based target contours of the 1st fraction were applied forplanning of the 2nd application on CT images, the actual HR CTV volumes
differed on average by 0.1±4.6 cm (mean±1 SD). For a prescribed doseof 7 Gy per fraction the D90 was therefore underestimated by 0.3±1.0 Gy(mean±1SD) compared to doses from the original, fully MRI-based clinicalplans of the 2nd BT applications. Only one of the CT-based plans failed toachieve the targeted D90 on corresponding MR contours by 0.5 Gy.Only for
one patient the dose to an OAR varied by more than 1 Gy per fraction, due
to substantial intrafraction variations of the sigmoid between CT and MRI
imaging of the same day and/or contouring uncertainties on CT, which would
have lead to a violation of the clinical dose constraint.
Conclusions: This study proves the feasibility of a combination of one MRI
sequence at the beginning of BT and CT-based treatment planning of subsequent fractions by reuse of the initial MRI target contour. Uncertainties in
automatic target transfer can be minimized by using a 2mm slice thickness for
CT. At least for small tumours the proposed technique produces comparable
results as the current "gold standard". Therefore it could be applied for 3Dimage guided adaptive BT in centres with limited access to MRI. However,uncertainties in contouring on CT without contrast medium may lead to nonnegligible underestimation of the sigmoid dose.(Supported by the Austrian
Science Fund (FWF), project L562)
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INTEGRATED ON-BOARD CBCT-ULTRASOUND IGRT OF SOFT
TISSUE TARGETS
J. Wong1 , P. Kazanzides2 , I. Iordachita2 , P. Xia3 , M. Lachaine4 , K.

Results: To avoid detector saturation by over-exposure to MV radiation, theread-out frequency was set to 15 Hz and the detector gain to its lowest possible setting of 8 pF. By triggering x-ray pulse and detector simultaneously
within a sub-ms tolerance using an in-house developed software and hardware solution, it was possible to maximise the kV-to-MV signal ratio. As two
subsequent frames are acquired within 132 ms, the deduced kV image is inherently offset-corrected and free of ghosting artefacts. A phantom study has
demonstrated that our imaging framework is capable of automatically detecting the position of metallic markers and sending this information to the DKFZ
tracking tool with a latency of about 130 ms and a 7.5 Hz update rate. The
additional kV dose amounts to less than 0.1 mGy per projection.
Conclusions: As of today, our system is able to monitor intra-fractional target
motion with the aid of metallic markers. In future, we seek to extract further
anatomical information from the kV images and reduce system latency. Disclaimer: Partially funded by Siemens Med OCS.
242 oral
BETWEEN GOLD STANDARD AND REALITY: IMAGE GUIDED
ADAPTIVE BRACHYTHERAPY FOR CERVICAL CANCER PATIENTS,
WITH MRI ONLY AT FIRST FRACTION
N. Nesvacil1 , A. Sturdza1 , M. Federico2 1 , N. Hegazy3 1 , R. Pötter1 , C.
Kirisits1
1
M EDICAL U NIVERSITY OF V IENNA, Department of Radiotherapy, Vienna,
Austria2
U NIVERSITY OF PALERMO, Department of Surgery and Oncology, Palermo,
Italy
3
A LEXANDRIA U NIVERSITY - FACULTY OF M EDICINE, Department of clinicaloncology and nuclear medicine, Alexandria, Egypt
Purpose: At the Medical University of Vienna the standard for brachytherapy(BT) for cervix cancer patients is to apply 4 HDR fractions of 7Gy in 2 applications which are done in consecutive weeks. For each fraction treatment
plans are optimized based on MRI with applicator in place. This "gold standard" may not be feasible for centres with limited access to MRI. In order toovercome the shortcomings of target delineation on CT, it is recommended
to use at least one MRI at the beginning of BT.The aim of this retrospective
study was to investigate the technical feasibility combining an initial MRI sequence with consecutive CT-based planning using a software solution, and tocompare the dosimetric outcome of this technique to the MRI gold standard.
Materials: For 15 patients the 1st MRI of the 1st BT application was fused with
CT images of the 2nd application using the OncentraGYN treatment planningsystem (v1.2.3, Nucletron). The reconstructed tandem-ring applicator was
the reference basis for automatic image registration. Target contours outlinedon the 1st MRI were automatically transferred to the CT according to the applicator position. Treatment plans for the 2nd BT application were created,taking into account the actual positions of organs at risk (OAR) delineated on
CT and the related dose constraints. For the resulting plans two sets of DVH
parameters were evaluated and compared: i) based on the transferred target,

Stephans3 , J. Herman1
1
J OHN H OPKINS H OSPITAL, School of Medicine, Baltimore MD, USA
2
J OHN H OPKINS U NIVERSITY, W HITING S CHOOL OF E NGINEERING,
Department of Computer Integrated Surgical Systems and Technology,
Baltimore, USA
3
C LEVELAND C LINIC, Radiation Oncology, Cleveland OH, USA
4
E LEKTA CMS, Maryland Heights, USA
Purpose: Localization of soft tissue targets can be challenging with CBCT
in IGRT. "Snap shot" CBCT also does not allow for continuous monitoring of
the intended target. At present, intra-fraction verification of these treatments
has resorted to localizing implanted markers with AC electromagnetic or xray detection. These are invasive procedures. Additional x-ray imaging doseis also of concern. 3D ultrasound imaging would offer an effective means
for non-invasive, non-ionizing, soft tissue localization, although it has been
applied only in the setting of pre-treatment setup. We have thus initiated thedevelopment of an integrated on-board 3D ultrasound and CBCT imaging
system to provide a superior IGRT solution than current methods for the soft
tissue target localization.
Materials: The ultrasound system will be deployed at time of simulation forsoft tissue imaging. The effects of CT artifacts on dose calculation due to theultrasound probe are examined. The ultrasound probe will be positioned atevery treatment fraction as part of setup with CBCT. It will remain in place
during beam-on for continuous monitoring of intra-fraction motion. Concerns
for user dependency and tissue deformation are resolved by employing a
3D ultrasound probe whose placement is under robotic control. CT scans
were acquired of a gel phantom with imbedded markers that were repeatedly
deformed under controlled compression. The reproducibility of the markers’
positions was measured. The effects of radiation on ultrasound image quality
were measured by placing an active probe 1 cm adjacent to the edge of an
18 MV beam operating at 400 MU per min. Finally, one beam from a 7beam IMRT treatment plan of a liver lesion was removed to accommodate
the placement of the ultrasound probe. The resultant dosimetry of the reoptimized 6-beam arrangement was compared with that of the original plan.
Results: Radiation adjacent to the probe did not affect the ultrasound image
quality. CT artifacts due to presence of an ultrasound probe perturbed thecalculated dose of an 6 MV beam by 20%. When the gel phantom was deformed repeatedly under the same compression, positions of the implanted
markers were reproduced to within 0.3 mm. Dosimetric quality (e.g. DVH,etc) of the 6-beam arrangement was similar to that of original 7-beam plan.
Many beam arrangements can be employed to effectively accommodate thepresence of an ultrasound probe.
Conclusions: An integrated x-ray/ultrasound image guidance system allows
verification of the 3D treatment setup and continuous monitoring of the soft
tissue targets during treatment. The procedure is non-invasive and avoids
x-ray imaging dose. CT artifacts induced by the ultrasound probe for planningpurposes can be avoided by acquiring ultrasound images of the patient intreatment position before CT scanning, and replacing it with a CT compatiblemodel during scanning.

T UESDAY, M AY 10, 2011244 oral
CAPABILITIES AND INHERENT LIMITATIONS OF OPTICAL BODY
SURFACE SENSING USING FOURIER PROFILOMETRY
G. Whitfield1 , G. Price2 , P. Price1 , J. Stratford3 , G. Watkins1 , T. Marchant2 ,A. Jackson1 , J. Davies3 , C. Moore2
1
U NIVERSITY OF M ANCHESTER, Radiotherapy Related Research, Manchester, United Kingdom
2
C HRISTIE H OSPITAL NHS F OUNDATION T RUST, North West Medical
Physics, Manchester, United Kingdom
3
C HRISTIE H OSPITAL NHS F OUNDATION T RUST, Wade Centre forRadiotherapy Research, Manchester, United Kingdom
Purpose: i) To assess whether a novel optical sensor (OS) is capable ofaccurate body surface measurement and ii) define limitations and potential
solutions.
Materials: The OS1 is to our knowledge the only body surface sensor using Fourier profilometry2 , which unlike triangulation or stereophotogrammetry
calculates the surface ’en masse’ from a single camera frame. 3 independent
sensors, each made up of a projector, camera with zoom lens and 3GHz CPU
are arranged above the radiotherapy couch to give a wrap-around patient
view. A fourth master computer interfaced to the Elekta Synergyinear accelerator synchronises OS and cone beam CT (CBCT) recordings. Each sensor
projects a cosine fringe pattern with 7 spots superimposed, in red, green or
blue, captured at 25 frames/s by the corresponding camera. Relative surface
height is decoded by Fourier transform fringe analysis and absolute height by
spot triangulation. Spatial and temporal resolution are limited only by camera resolution (512 x 512 pixels) and frame rate. Recordings of thorax andupper abdomen were obtained in a human-like phantom and in oesophageal,pancreatic and lung cancer patients (Jul 09-Jan 10). In the phantom, opticalsurface accuracy was assessed by comparison with the CT surface. In patients 500 frame mean optical surfaces were compared with simultaneously
acquired CBCT surfaces to assess plausibility of surfaces.
Results: In the phantom, central optical surface accuracy was excellent (distance to CT surface mean 1.2, SD 1.2 mm) with lateral surfaces less accurate(mean 2.2, SD 1.3 mm and mean 4.5, SD 2.3 mm). The 32 mean optical surfaces in 4 patients varied from very good to poor; mean distance to CBCT
surface varied from 1.4 to 12.5 (median 4.3) mm, SD from 1.1 to 9.3 (median2.7) mm.
Conclusions: The OS is capable of accurate, high speed surface measurement. Our research with a single overhead OS with a narrower field of view(FOV) suggests geometry and large FOV (0.4 x 0.7 m) are the main sourcesof inaccuracy: +/- 1 or 2 pixel error in spot detection leads to +/- 2.3 or 4.6 mm
height error; mount stability is also key. Greater angular separation of cameras and projectors improves spot triangulation but reduces ability to detect
steep gradients normal to the fringes (Fourier method gradient limitation)2 .
The Nyquist limit (1/2 fringe period) determines the smallest object visible,
which affects surface detail and may add to height uncertainty in high gradient areas. Improvements (reduced FOV, higher resolution cameras and projectors, white spot(s) visible to all 3 sensors to ensure agreement in overlap
areas, triangulating between different sensors to increase angular separation, rotating fringes on lateral surfaces to run parallel to surface gradient) are
ongoing to improve surface accuracy.1.Proceedings, SPIE Medical Imaging
2010;7622:76224B-1 to B-12.2.Fourier transform profilometry for the automatic measurement of 3-D object shapes. Applied optics 1983;22:3977-82.

Physics Proffered Papers 6: IGRT: 4D and Breathing Adapted
245 oral
COMPARISON OF DIFFERENT STRATEGIES FOR RESPIRATORYMOTION CORRECTION OF CONE-BEAM CT IN LUNG CANCER
SBRTS. Rit1 , J. Nijkamp2 , M. van Herk2 , J. J. Sonke2
1
U NIVERSITÉ DE LYON ; CREATIS ; CNRS UMR5220 ; C ENTRE L ÉON
B ÉRARD, Lyon, France
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands
Purpose: Large scale evaluation of different strategies for respiratory motion correction of cone-beam (CB) CT in lung cancer stereotactic body radiotherapy (SBRT) before clinical replacement of 4D CBCT with motioncompensated CBCT.
Materials: We selected the 48 lung patients which underwent SBRT at theradiotherapy department of the Netherlands Cancer Institute between February 2008 and November 2009, and which tumor motion on 4D planning CT
had a peak-to-peak amplitude greater than 5 mm in one direction. The 4D
planning CT was used to compute a 4D deformation vector field (DVF) using deformable registration. Two CB scanning procedures were used at eachtreatment fraction: two long acquisitions (4 min) for 4D CBCT and one shortacquisition (1 min) for 3D CBCT. Each patient had 5 to 12 long scans andP ROFFERED PAPER

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1 to 7 short scans depending on adjustments in the protocol (349 and 150
in total). Three CBCT reconstructions were performed from each CB acquisition: non-corrected (3D) CBCT, respiration-correlated (4D) CBCT andmotion-compensated (MC) CBCT. The latter two, developed and publishedby the authors, use an image-based respiratory signal. MC CBCT also compensates for the motion described by the DVF during reconstruction. The tumor region of the time-averaged planning CT was registered on each CBCT
image. Three metrics were used to assess the CBCTs: correlation ratio forimage quality, registration accuracy with respect to 4-D CBCT and the motion
amplitude before and after compensation.
Results: The mean image quality of long / short scans was 74% / 70%, 67% /47% and 79% / 74% for 3D, 4D and MC CBCT, respectively. 4D CBCT image
quality was significantly worse (p<10-8 ) than the other two due to noise andstreak artifacts. MC CBCT image quality was significantly higher than 3D
CBCT (p<10-5 ) thanks to the correction of motion blur. Only the registration
accuracy of the long acquisitions is discussed due to higher 4D CBCT image
quality (Table 1). Non-corrected CBCT induces a significative 0.7 mm groupmean in the craniocaudal direction (p<10-3 ) because end-exhale tends to be
more defined on the blurred 3D CBCT image. In contrast, MC CBCT has no
significant group mean (p>0.75). The systematic and the random errors of
MC CBCT were also lower than 3D CBCT. Finally, the median / 95 percentile
peak-to-peak motion amplitude was 5.3 / 10.9 mm and 2.5 / 6.0 mm before
and after compensation, respectively

Conclusions: Using 4D CBCT as a reference registration, MC CBCT improves tumor registration compared to 3D CBCT thanks to substantial motion
compensation. In contrast to 4D CBCT, it gives acceptable image quality witha short acquisition. It is therefore a good candidate to clinically replace 4D
CBCT.
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4D-CT RECONSTRUCTION USING MV PORTAL IMAGING DURING
VOLUMETRIC MODULATED ARC THERAPY
S. Kida1 , N. Saotome1 , A. Haga1 , Y. Masutani1 , H. Yamashita1 , A.
Sakumi1 , K. Ohtomo1 , N. Keiichi1
1
U NIVERSITY OF TOKYO, Tokyo, Japan
Purpose: Recently, Poludniowski et al., investigated the possibility to acquirereconstruction images from MV beams during volumetric modulated arc therapy (VMAT) treatment, named as "VMAT-CT" (Phys. Med. Biol. 55 (2010)5635). In this study, we develop its four-dimensional (4D) version and compare it with in-VMAT kV-CBCT images.
Materials: The treatment planning for lung cancer patients was created with
D95 prescription of 50 Gy in 4 fractions using single-arc VMAT-SRT based on
the beam’s eye view strategy with Pinnacle v9.0 (Philips). A phantom study
using QUASAR (Modus Med. Inc.) and three actual clinical treatments havebeen performed by Synergy accelerator (Elekta). MV-portal images during
VMAT beam delivery were acquired using the iView software. The projection
angles were determined by comparing leaf positions from the portal images
with those recorded by iCOM which also has a gantry angle information. Simultaneously, kV-portal imaging orthogonal to MV imaging was performed
during VMAT delivery. Using the kV-portal images, a respiratory signal wasderived by image-based phase recognition technique. Synchronizing withkV ones, then, MV-portal images were classified to corresponding breathingphase bins. Consequently, both 4D VMAT-CT and 4D kV-CBCT were reconstructed independently with conventional filtered-back projection algorithm.
Results: Treatment time was 270 second on average. Leaf positions obtained by MV images as field edge detection of 50% for maximum value andassuming the capture rate of 0.46 sec interval, were in agreement with a log
data recorded by iCOM within 2mm. This result allows to synchronize thesequence of MV imaging with kV imaging. Right-upper panel of figure shows
VMAT-CT at inspiration while right-lower panel shows that at expiration. It
is found that tumor size and its position are very similar to those of kV 4DCBCT’s indicated in left panel.

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4DCT – HIGH QUALITY IMAGING AND CONTRAST ENHANCEMENT
FOR 3D RADIOTHERAPY TREATMENT PLANNING
C. Schneider1 , J. Nijkamp1 , S. Rit1 , M. van Herk1 , J. J. Sonke1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

247 oral
THE USE OF A GLOBAL RESPIRATORY MOTION MODEL FOR REALTIME 4D RADIOTHERAPY APPLICATIONS
H. Fayad1 , T. Pan2 , D. Visvikis1
1

INSERM U650 L ATIM, Brest, France
MD A NDERSON C ANCER C ENTER, Department of physical imaging,
Houston, USA
2

Purpose: Respiratory motion modeling is a key aspect for improving radiation
therapy, with the objective of delivering less dose to the normal tissues andhigher dose to the tumor during the breathing motion cycle. The main idea of
this work is the use a generic respiratory motion model to predict in real-time
the respiratory motion of the tumor and the adjacent anatomy.
Materials: The generic respiratory motion model used in this work is basedon principal component analysis. Only two static CT images (end-inspiration,
end-expiration) in combination with respiratory synchronized patient’s bodysurface are needed to adapt the model on a given patient anatomy. This
generic model relates the patient’s surface acquired by an external camera
and the internal motion calculated using a non rigid registration algorithm.
The resulting patient adapted model is subsequently used to generate in realtime the motion of the tumor and the adjacent anatomy. In this study 6 patients were used to create the model and 4 other patients were used in thevalidation step. The intrinsic model efficiency was tested by comparing model
generated 4D-CT volumes and their corresponding acquired 4D-CT volumes.
The model based motion information is subsequently used to improve planning and delivery of 4D-IMRT by accounting for 3D tumor (Suh et al 2009) as
well as normal tissue motion. The whole schema of the procedure is shownin figure 1.

Results:
Good correlation (r=0.93±0.4) and expert validation(1.9mm±0.6mm: based on expert anatomical landmarks identification) was found between the model generated series and the acquired 4D-CT
volumes. Preliminary results indicate that including the normal tissue motion
provided by our motion model during the delivery of the 4D-IMRT is better interms of dose delivery optimization than simply accounting for tumor motion.
Conclusions: The use of a global respiratory motion model, which may be
adapted on a specific patient, for radiotherapy applications avoids unnecessary 4D-CT acquisitions. Accounting for normal tissue motion helps to optimize 4D dosimetry compared to considering the tumor motion only.

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scan construction from 4D-respiration-correlated CT-scans. IJROBP 2006;
65:1560-1571.

248 oralConclusions: The visualization of actual dose region delivered in a treatment has been available by means of VMAT treatment. The VMAT-CT superimposed on in-VMAT kV-CBCT could be a visual verification of the actual
treatment in the high-precision treatment era.

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249 oral
MV IMAGE-BASED DYNAMIC MLC TRACKING OF A NITI STENT IN
PIG LUNGS ON A LINEAR ACCELERATOR
P. R. Poulsen1 , J. Carl2 , J. Nielsen2 , M. S. Nielsen2 , J. B. Thomsen2 , H.
K. Jensen3 , B. Kjærgaard4 , P. R. Zepernick4 , E. Worm1 , W. Fledelius1 , B.
Cho5 , A. Sawant6 , D. Ruan7 , P. Keall89
1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
A ALBORG H OSPITAL , U NIVERSITY OF A ARHUS, Department of Medical
Physics, Aarhus C, Denmark
3
A ALBORG H OSPITAL , U NIVERSITY OF A ARHUS, Department of Pulmonary
Medicine, Aarhus C, Denmark
4
A ALBORG H OSPITAL , U NIVERSITY OF A ARHUS, Department of Thoracic
Surgery, Aarhus C, Denmark
5
A SAN M EDICAL C ENTER, Department of Radiation Oncology, Seoul, Korea
Republic of
6
UT S OUTHWESTERN M EDICAL C ENTER, Dallas, USA
7
U NIVERSITY OF C ALIFORNIA , L OS A NGELES, Department of Radiation
Oncology, Los Angeles, USA
8
S TANFORD C ANCER C ENTER, Department of Radiation Oncology,
Stanford, USA
9
T HE U NIVERSITY OF S YDNEY, Sydney Medical School, Sydney, Australia

Purpose: Planning of radiotherapy for moving tumours in lung or abdomen
can be based on respiration-correlated CT-imaging of the tumour in a timeweighted averaged (TWA) position. Locating the closest bin in the respiration period corresponding to the TWA position (MidV-CT) has drawbacks :irregular breathing causes artifacts, while signal to noise ratios and contrast
enhancement (CE) are poorer than in standard 3D-CT. These drawbacks canbe overcome by deforming all 4D image data available to a TWA-3D scan toa Mid-Position (MidP)-CT, as proposed by Wolthaus et al [1]. The purpose ofthis study is to evaluate the effect of this method on image quality.
Materials: For evaluation of the new technique, 10 patients were selectedwith a clearly visible tumour in the periphery of the lung. For all patients,
a 4D-CT and an expiration breath-hold (BH) CT were acquired. For 5 ofthese patients, contrast was given during BH-CT. The 4D-CT-scans were reconstructed in 10 bins over the respiration cycle.The resulting 10 image sets
were deformable registered, applying an iterative multi-scale phase-based
optical flow estimation procedure. For each patient 2 different registrations
were performed. First, the image set at maximum expiration was used as
reference scan to which all other image sets were registered. Next, the average Displacement Vector Field (DVF) over all image sets was subtracted fromeach DVF yielding all deformations with respect to the TWA position. These
DVF were applied to deform all image sets to the TWA position. Finally, the
MidP-CT was calculated as median grey-value for each pixel over all 10 image sets. In the second procedure, an additional DVF from the BH-CT to the
TWA position was calculated. With the latter, a MidP-BH-CT was calculated
by deforming the BH-CT to the TWA position.
Results: Compared to MidV-CT, the MidP-CT improved by: 1) clearly reduced frequency of irregular motion artefacts, 2) increased signal to noise
ratio and 3) CE increased to about 120 HU in vessels at the levels of tumour. Especially for tumours close to the thoracic wall, tumour amplitudes
measured with deformable registration appeared slightly smaller than withthe rigid registration method (sliding tissue effects).

Purpose: Intrafraction tumor motion is a major challenge for precise radiotherapy of lung cancer. Dynamic MLC (DMLC) tracking is an attractive option
for motion compensation and has therefore been the subject of several recent
phantom studies. This work presents the first demonstration of in vivo DMLC
tracking in a mammal and investigates the accuracy and potential limitationsof the tracking.
Materials: A thermo-expandable NiTi stent designed for kV x-ray visualization of lung lesions was inserted into the bronchia of three Gttingen minipigs.
A 4DCT scan was used for planning of a 5-field conformal treatment with 6
cm circular MLC apertures. A 22.5 Gy single fraction treatment was delivered to the anaesthetized pigs. The peak-to-peak stent motion was 3-8 mm
with breathing periods of 1.2-4 seconds. Prior to treatment a pair of x-ray
images was used for image guided setup based on the stent. Before eachfield delivery about ten MV images were acquired. A small area centeredat the stent was selected and used as a template for stent segmentation incontinuous MV images acquired at 7.5 Hz during treatment. The segmented
stent position was used for continuous adaptation of the MLC aperture (Fig.
1). A prediction algorithm accounted for the 400 ms tracking system latency.
Offline, the tracking error in beam’s eye view of the MV beam was calculated
for each MV image as the difference between the MLC aperture center andthe segmented stent position. The standard deviations of the systematic errorΣ and the random error σ were determined and compared with the would-be
errors for a non-tracking treatment with pre-treatment image guided setup.
The pigs were sacrificed after the treatment while still anaesthetized. The
study was approved by The Animal Ethics Council under the Danish JusticeDepartment.

Figure 1: Overview of image quality for CT-slice in mediastinum: MidV CT(top), a MidP CT (middle) and MidP BHCT (bottom) at identical level andwindow settings.
Conclusions: Deforming all image sets derived from clinical 4D-CT-scans
to a MidP-CT is a robust technique and ready to be introduced in the clinic.
Image quality improves in reduced artefacts and noise. This approach also
facilitates application of CE in 4D workflows. Thus, more accurate and reproducible delineation of the tumour and involved lymph nodes is expected.
Wolthaus JW, Schneider C, Sonke JJ, van Herk M et al. Mid-ventilation CT

Results: Reliable stent segmentation was obtained for 11 out of 15 fields.
Segmentation failures occurred when the image contrast was dominated byoverlapping anatomical structures (ribs, diaphragm) rather than by the stent,
which was designed for kV rather than MV x-ray visibility. For the 11 fields
with reliable segmentation Σ was 0.5 mm / 0.4 mm in the two imager directions, while σ was 0.5 mm / 1.1 mm. Without tracking Σ and σ would havebeen 1.7 mm / 1.4 mm and 0.8 mm / 1.4 mm, respectively. For tracking, themain contributors to Σ were gantry sag and positioning reproducibility of the
MV imager, which could easily be accounted for by an automatic online correction. The main contributor to σ was the latency (400 ms), which could besubstantially reduced with direct image buffer access.
Conclusions: For the first time, in vivo DMLC tracking has been performed
on a linear accelerator demonstrating the potential for improved targeting accuracy. The study mimicked the envisioned patient workflow of future patient

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treatments. Clinical implementation of MV image based tracking would require markers designed for MV visibility.
250 oral
LOW DOSE FLUOROSCOPY BASED DETECTION OF IMPLANTEDMARKER POSITION ON THE VERO SYSTEM FOR REAL-TIMETUMOR TRACKING
T. Depuydt1 , K. Poels1 , G. Van Gompel2 , N. Buls2 , D. Verellen1 , M. De
1

RidderUZ-B RUSSEL, Radiotherapy Department, Brussel, Belgium
UZ-B RUSSEL, Radiology Department, Brussel, Belgium

1

T UESDAY, M AY 10, 2011
251 oral
GEOMETRIC ACCURACY OF DYNAMIC MLC TRACKING WITH AN
IMPLANTABLE WIRED ELECTROMAGNETIC TRANSPONDER
T. Ravkilde1 , P. J. Keall2 3 , K. Hoejbjerre1 , W. Fledelius1 , E. Worm1 , P. R.
Poulsen1
1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
U NIVERSITY OF S YDNEY, Sydney Medical School, Sydney, Australia
3
S TANFORD U NIVERSITY, Department of Radiation Oncology, Stanford,
USA

2

Purpose: To determine the balance between kV fluoroscopy imaging dose
and the image quality, for robust detection of implanted fiducial markers inlung on the VERO system.
Materials: The VERO system is capable of real-time tracking of moving tumors. A solution to improve tumor visibility in fluoroscopic images is an implanted fiducial marker in or near the tumor. In total 5 types of fiducial markers
were placed statically in the imaging beam: solid gold markers (CIVCO, Heider), helical coils (FlexiCoil,Visicoil), multiple gold marker assemblies (FlexiMark), spherical markers and stent like markers (MemoCore). To investigate
the interaction of marker detection with projection on the heterogeneous andhigh density structures in the thorax fluoro images, an anthropomorphic phantom was placed on a moving platform behind the markers. Fluoro sequenceswere acquired with variable tube current (0.5 mAs up to 4.0 mAs), kVp, andfor different surrounding anatomical circumstances. Additionally mAs was
physically reduced beyond 0.5 mAs using up 27.0 mm of Al sheets. A marker
detection algorithm was developed using maximization of normalized crosscorrelation with a template library incorporating marker rotations onto unprocessed images. The templates were created from a 3D model of the marker.
The algorithm is detecting both position of the marker as its in-plane and outof-plane rotation. For each fluoro sequence, the marker detection was applied on 25 images and detection scores calculated. Detection success was
defined as agreement with a reference better then 5 pixels of 0.18mm. To relate the findings to imaging dose on the VERO system, TLD measurements
were conducted for a number of different imaging settings.

Purpose: Tumor motion during radiotherapy treatment delivery can substantially deteriorate the target dose distribution. A promising method to overcome
this problem is dynamic multi-leaf collimator (DMLC) tracking, where the MLC
aperture is continuously adapted to the tumor position. The purpose of thisphantom study was to integrate a wired electromagnetic transponder localization system with DMLC tracking and to investigate the geometric accuracyof the integrated system.
Materials: DMLC tracking experiments were performed on a Trilogy accelerator (Varian Medical Systems, Palo Alto, CA) with a prototype DMLC tracking
system. A wired implantable electromagnetic transponder (RayPilot, Micropos Medical AB, Gothenburg, Sweden) was mounted on a motion stage witha 3 mm tungsten sphere used for target visualization in MV images. The
transponder signal was received by antennae arrays in the table top and used
to generate a 3D transponder position signal with 30 Hz frequency. The position signal was sent to a DMLC tracking program that continuously adapted
the MLC aperture to the transponder signal position. A 10 cm circular MLC
aperture was used in all experiments. Continuous MV images acquired at 7.5
Hz were used to determine the MLC aperture center position and the tungsten sphere position in beam’s eye view of the treatment beam. The tracking system latency was determined as the time lag between the tungsten
sphere motion and the MLC aperture motion in the MV images for a sinusoidal motion. The geometric accuracy of the tracking system was measured
by programming the phantom to reproduce four representative lung tumor trajectories (originally measured with a Cyberknife Synchrony system) and four
representative prostate trajectories (originally measured with Calypso electromagnetic transponders). Prediction was used for the lung tumor trajectories
to account for the latency. For each trajectory, three treatments of 72 seconds
duration were delivered: (1) a 358◦ arc field, (2) a vertical static field, and (3)a horizontal static field. The beam-target error was determined for each MV
image as the 2D positional difference between the tungsten sphere and the
MLC aperture center. The root-mean-square (rms) of the beam-target error was determined for each field for each trajectory and compared with thewould-be error without tracking.
Results: The tracking system latency was 140 ms. Fig. 1 shows the 2D rms
beam-target errors for each trajectory for the arc fields. Tracking reduced themean rms error from 4.9 mm to 1.0 mm for lung tumor trajectories and from
3.4 mm to 0.7 mm for prostate trajectories. Static fields gave very similar
results.

Results: Differences were seen in the marker detection scores for the different types of markers in the different anatomical situations. Beside the intrinsic
attenuation of the marker, also its spatial structure played a role in the detection success. Only one type of the marker was detected in all images, even forlow mAs :the FlexiMark, consisting of two gold markers connected by a gold
wire. The single gold marker and coil structure showed decreased detection
score in the proximity of the spinal cord bone edges. The Memocore, having
a lower density, also showed detection failures projected on the ribs. Increasing the mAs did not always increase detection scores. For 0.5 mAs, 100kVp
and an SSD of 900mm a skin dose was measure of 0.031 mGy/image andan exit dose of 0.001 mGy/image. At a frame rate of 14 fps this would mean
an imaging skin dose of 26.04 mGy/min.
Conclusions: With fiducial markers, it is feasible to use fluoroscopy based
real-time tracking with imaging doses comparable to CBCT. Markers with amore elaborate structure made from high density materials have, beside anadvantage of being less prone to migration, also an advantage in terms ofdetection scores when projected on anatomical structures in fluoroscopic images of the thorax.

T UESDAY, M AY 10, 2011
RTT Proffered Papers 3: Treatment Planning and
Delivery
252 oral
DOES DOSE RATE AND GANTRY SPEED PROVIDE SUFFICIENT
DEGREES OF FREEDOM TO ALLOW FOR MULTI-CRITERIA VMATPLANNING?
R. Bokrantz12 , K. Eriksson2 , B. Hardemark2
1
R OYAL I NSTITUTE OF T ECHNOLOGY, Department of Mathematics,
Stockholm, Sweden
2
R AY S EARCH L ABORATORIES, Stockholm, Sweden
Purpose: VMAT allows for irradiation during MLC leaf movement and gantry
rotation. Additional degrees of freedom together with constraints imposed by
the delivery technique make VMAT planning a more challenging and time consuming optimization problem than that of fixed-beam IMRT. We hypothesizethat VMAT due to its high complexity would largely benefit from an interactiveplanning process that allows for informed decisions between conflicting treatment goals. To this end, we evaluate a novel approach for multi-criteria VMAT
planning based on averaging between pre-computed plans with shared MLC
shapes in order for combinations between plans to comply with the delivery
constraints. The final plan selected for delivery is identified using a graphical user-interface that allows for smooth transitions in real-time between precomputed plans.
Materials: 359-degree dual arcs were generated for a prostate and a headand neck case in the RayStation treatment planning system (RaySearch Laboratories, Stockholm, Sweden). Both cases were planned for delivery with a
Varian 2100 linac with 2-degree spacing between control points. Optimization with respect to dose rate, gantry speed and leaf positions was performed
towards weighted dose-volume objectives set according to standard recommendations. Initial MLC shapes were created by sequencing optimized fluence maps at 24-degree increments from the start angle into control points
and then distributing these over adjacent gantry angles. A collection of 25
treatment plans with shared MLC settings was then generated by optimizing
a VMAT plan with unity weights followed by an optimization of dose rate andgantry speed with weights on target objectives varying over the interval [0.1,10]. A collection of reference plans for evaluatory purposes was created by
an identical procedure except that both optimization steps were performed
with respect to the varying objective weights.
Results: Tradeoff curves between tumor coverage and OAR sparing for thehead and neck case are shown in Figure 1. Disconnectedness for the curve
spanned by the reference plans can be attributed to different initial MLC
shapes. The curve spanned by plans with shared MLC shapes aligns withthe reference curve within the variability of this curve and covers about 75 %of the range of the reference curve with respect to improving OAR sparing
and about 10 % of the range for improving target conformity, indicating thatdose rate and gantry speed primarily provides maneuverability with respect
to OAR sparing.

Conclusions: Multi-criteria VMAT planning based on sharing MLC shapes
has been demonstrated. Combining pre-computed plans allows tradeoffs
between incompatible objectives to be explored without having the planning
process interspersed with parameter tweaking and re-optimization. Further
studies are necessary to assess the treatment quality of plans generated by
the proposed technique.
Conclusions: DMLC tracking was integrated with a novel electromagnetictransponder localization system and investigated for arc and static field delivery. The system provides sub-mm geometrical errors for most trajectories.
The tracking latency is the shortest reported so far for DMLC tracking.

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253 oral
CLINICALLY RELEVANT PARETO FRONTS
T. Janssen1 , Z. Kesteren van1 , E. Damen1 , C. van Vliet-Vroegindewij1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

1

Purpose: To implement a framework which allows for the construction andevaluation of clinically relevant Pareto fronts in Pinnacle and, as an example, use this framework to compare IMRT with VMAT for prostate patients.
In evaluating a treatment plan, one typically has conflicting evaluation objectives (EO). Plans where one cannot improve on one EO, without worsening
another, span up the Pareto front. In treatment planning studies, one typically only compares points from near the Pareto front. The choice of a point
however is subjective and thus an observed difference may simply be due
to different choices. Comparing the complete front however presents an objective way to compare techniques.For clinical relevance the fronts need tobe constructed conform clinical practice, using a clinical treatment planningsystem, with the clinical planning objectives (PO) and the clinical EO.
Materials: An application has been written which runs many optimizations
using the Pinnacle treatment planning system with different PO for each run
to steer the optimizer. New PO are generated by randomly changing parameters like the weight, or the dose level of a ’master set’ of PO. After optimization, plans are normalized and the data is saved for evaluation.From the plans
the Pareto front for a set of EO is constructed using Matlab. To compare two
fronts, for each EO a Pareto Similarity Index, Ψ, is defined as the average relative difference between the fronts of that EO. Ψ is normalized to lie between-1 and +1 such that two Pareto fronts are equal for Ψ = 0. See the table forexamples. As an example of the framework described, we have compared
the Pareto fronts of VMAT with IMRT for three prostate cases. Our clinicalset of PO was used as a ’master set’ and plans were normalized to obtainthe clinically required PTV coverage. Pareto fronts were generated based on
1000 plans for a set of EO consisting of the PTV homogeneity and the V75Gy
and V65Gy of the rectal wall. Ideally all these EO are zero.
Results: Constructing and evaluating the Pareto fronts takes about 60 hoursof CPU time per patient and about 15 minutes of human interaction. Ψ for thedifferent patients and EO is given in the table and an example front is shownin the figure. We see that for all patients, for all EO, Ψ is positive, implying inthis case that the Pareto front for the VMAT plans lays lower.

Conclusions: We have successfully implemented a framework to construct
and evaluate Pareto fronts using Pinnacle. The fronts are a realistic representation of clinical practice, since they are based on the clinical PO, the clinicaltreatment planning system and the clinical EO. This framework allows for an
objective comparison between planning techniques, without the arbitrarinessdue to the choices of a planning RTT. As an example we compared VMAT
with IMRT for prostate patients. We found that for the plans which are Paretooptimal for the PTV homogeneity and the V75Gy and V65Gy of the rectal
wall, the VMAT plans are superior for each EO.

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255 oral

ROBUST OPTIMIZATION ACCOUNTING FOR ORGAN MOTION,RANGE ERRORS, AND SETUP ERRORS IN IMPT
A. Fredriksson1 2 , B. Hardemark2
1
R OYAL I NSTITUTE OF T ECHNOLOGY, Department of Mathematics,
Stockholm, Sweden
2
R AY S EARCH L ABORATORIES, Stockholm, Sweden

SBRT WITH VARIAN TRUEBEAM: TIME- EFFICIENCY AND PATIENTSTABILITY
A. Tini1 , A. Walker1 , F. Cavelaars1 , S. Lang1 , C. Winter1 , O. Riesterer1
1
U NIVERSITY H OSPITAL Z ÜRICH, Zurich, Switzerland

Purpose: The quality of IMPT plans may be severely compromised by suchfactors as range errors, setup errors, and organ motion. Conventional margins are often insufficient to account for these errors, but robust optimization
methods have been shown practicable for handling of range and setup errors.
The purpose of this work is to study how well a robust method handles organ
motion in addition to the previously studied uncertainties.
Materials: Robust and conventional plans for a lung case and a prostate casewere optimized in the RayStation treatment planning system. The robust
plans were achieved by minimization of a scenario based weighted power
mean objective function with no margin specified for the CTV. Isotropic setup
errors of 3 mm and density errors of 3 % were assumed for both patient cases.
For the lung case, the organ motion was assumed to be 5 mm inferiorlysuperiorly and 2 mm in the other directions. For the prostate case, the organ
motion was assumed to be 6 mm isotropically and markers were assumed
to be used for the positioning. The conventional plans used margins, SFUD,
and material override (MO) to account for the uncertainties. The conventionallung plan had a margin of 8 mm inferiorly-superiorly and 5 mm in the otherdirections. The prostate plan had a margin of 12 mm in the left-right direction
and 3 mm in the other directions. The robust optimization included 55 error
realization scenarios for each of the patient cases. During the optimization,
the effects of the errors were approximated by translating and interpolating
the spot weights in the spot weight grid for each beam. In the plan evaluation,
the effects of the errors were evaluated by shifting the beam isocenters (forthe setup errors), scaling the mass density (for the density errors), and translating the CTV using deformable registration (for the organ motion errors).
The setup and organ motion shifts were randomly sampled from the ellipsoids of radii corresponding to the respective errors and the density scalings
were sampled from the interval [0.97, 1.03].
Results: The plans achieved using the robust method as well as thoseachieved using margins, SFUD, and MO resulted in robust target coveragefor both patient cases. For the lung case, the robust method resulted in lower
nominal and worst case dose to the lung as well as the external ROI than theconventional plan. For the prostate case, the nominal and worst case doses
to the bladder and the rectum were lower in the robust plan than in the conventional plan, as illustrated for the rectum in Figure 1.The plans achieved
using the robust method as well as those achieved using margins, SFUD,
and MO resulted in robust target coverage for both patient cases. For thelung case, the robust method resulted in lower nominal and worst case doseto the lung as well as the external ROI than the conventional plan. For theprostate case, the nominal and worst case doses to the bladder and the rectum were lower in the robust plan than in the conventional plan, as illustrated
in Figure 1, where 40 scenarios are shown for the robust (left) and the sfud
(right) method.

Conclusions: Robust optimization has been demonstrated suitable for handling organ motion in addition to density and setup errors. For the studied cases, it successfully enabled marginless planning and resulted in lower
doses to healthy tissues compared to conventional methods.

Purpose: With the advanced capabilities of the Varian TrueBeam we clinically
implemented an extracranial, hypofractionated stereotactic body radiotherapy(SBRT) program. Our purpose was to analyze patient stability and develop
imaging protocols to aid in accurate patient set up. In addition, we aimed toevaluate time efficiency for patient set up, imaging acquisition, and treatment
delivery.
Materials: Patients with lung or upper gastrointestinal tumors were immobilized with the CIVCO Body Pro-Lok system and stabilization devices. Using the patients 4DCT the internal target volume (ITV) was delineated andexpanded by 5.0mm to generate the PTV. For every treatment, kV paired
images and pre and post treatment CBCT were acquired to determine intrafractional patient motion. 2D-2D matching was based on bony anatomy
and 3D-3D was matched to the ITV and/or PTV. Daily set up deviations in
6 degrees of freedom were documented and translational and rotational errors were corrected. The treatment was delivered using high definition 2.5mm
MLCs. Several cases (5Gy- 10Gy per fraction) were treated with an increased
dose rate of 1400 MU/min using flattening filter free beams (FFF). Respiratory
tracking was utilized for all mediastinal volumes.
Results: On average 8.0min (1SD=2.9min) were required for patient setup in
the room. With kV paired images we needed 3.8min (1SD=1.8min) for bothacquisition and match procedures. CBCT acquisition required 1.5min and6.0min (1SD=2.8min) were needed for tumor match. Treatment beam-on timewas 3.6min (1SD=1.0min) with the total treatment time recorded at 25.0min(1SD=7.6min). The mean intrafractional motion as measured by repeated
CBCT was 1.0mm (1SD=0.6mm) with the maximum deviation of 2.3mm. The
CBCT showed a mean displacement of 7.3mm (1SD=3.0mm) from the treatment isocentre to the marked isocentre on the patients skin. Retrospectively
comparing the patients’ 2D-2D bony match with their 3D-3D ITV match resulted in a mean discrepancy of 2.7 mm.
Conclusions: SBRT with the Varian TrueBeam is highly time-efficient. Our
imaging protocol using CBCT results in stable patient positioning. Ongoingstudies investigate the impact of shortened beam-on times by use of highdose-rate FFF beams on patient stability. In addition, gated imaging andtreatment procedures as well as pitch and roll corrections are investigated.
256 oral
TOMOTHERAPY AND INTENSITY MODULATED PROTON THERAPYIN THE TREATMENT OF DOMINANT INTRAPROSTATIC LESION.
F. Fellin1 , R. Azzeroni2 , C. Fiorino2 , S. Lorentini1 3 , M. Schwarz1 , C.
Cozzarini2 , N. Di Muzio2
1
AGENZIA P ROVINCIALE PER LA P ROTONTERAPIA, Trento, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Milan, Italy
3
M EDICAL P HYSICS S CHOOL, University of Padova, Padova, Italy
Purpose: To compare HT (Helical Tomotherapy) and IMPT (Intensity Modulated Proton Therapy) dose distributions for prostate cancer with a boost on
the dominant intraprostatic lesion (DIL) up to 100 Gy.
Materials: Treatment plans of seven patients were designed for HT and IMPT.
Tomotherapy planning optimization was performed using a field dimensionof 2.5 cm, a pitch of 0.3 and a modulation factor of 4. 5-field IMPT plans
were optimized in the Hyperion treatment planning system, assuming a constant Relative Biological Effectiveness of protons of 1.1 and a small pencil
beam size (3mm sigma in air at isocentre). The prescribed dose was 71.4
Gy in 28 fractions in the PTV (defined as prostate + margin) and a median dose to DIL up to 100 Gy.In overlap between PTV and rectum, 95%of the volume should receive at least 64 Gy and the average dose must be
65.5-66 Gy at least.Dose tolerance for OARs were defined as follows:- Rectum: V40<60%, V65.5<20%, V68.5<5%, V70<1cc, Dmax≤80Gy;- Bladder:
Dmax=75Gy, as low as possible in the subvolume not in the PTV;- Femur
heads: Dmax<40Gy;- Penile bulb: V52<50%;- Urethra: v80<1cc, V90<0.1cc.
Results: A summary of the dosimetrical comparison is shown in the tablebelow. Both techniques complied with the minimum target coverage in the
PTV. IMPT achieved better target coverage and dose homogeneity than HT(p=0.002): the primary target coverage parameter (V95%) was better in IMPT
than in HT (98.8% vs. 95.5%, p=0.01). In all patients but one D99% was better by at least 3 Gy in IMPT. In the DIL volume, the median dose was reachedby both techniques and protons obtained a better D99% (75.5 Gy vs. 74 Gy).
The average dose in the overlap was the same for the two techniques (differences less than 1 Gy). Dose homogeneity in the overlap was slightly betterin HT than in IMPT. In all cases HT and IMPT plans complied with all OARs
dose-volume objectives. From 0 to 40 Gy the dose to the rectum was betterwith IMPT in all but one patient; above 40 Gy IMPT was in all patients equal
to or slightly better than HT.Concerning bladder, IMPT allowed a statisticallysignificant reduction of the dose from 0 Gy up to high doses (72 Gy); IMPT
reduced from 9% to 28% the average volume receiving 60 Gy or more. The
average mean dose was 16.5 Gy lower in IMPT than in HT.The dose deliv-

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ered to urethra was lower with HT; V80 and V90 was less than 9% and 1.3%
with HT, respectively. D1 was on average slightly better (1 Gy) with IMPT. In
the femoral heads, the dose was much lower with protons; IMPT techniques
allowed a large reduction of both V20 (41.6%) and D1 (18.5Gy).The average penile bulb mean dose and V52 were lower in IMPT by 17 Gy and 22%,
respectively.
Conclusions: HT and IMPT with small beams allowed to reach up to 100
Gy in the DIL volume, while complying with the OARs constraints. In general,
IMPT allowed better dose distributions both in terms of target coverage, dose
homogeneity and OARs sparing, with an increasing benefit for decreasing
doses.

Conclusions: Few (5%) of all patients fitting the criteria (2% all IMRT patients) had variations where the dose variation required replanning. The mostcommon reason for need for dose assessments was reductions in external
contour (mostly in head and neck treatments), followed by the need to adapt
to seroma changes in breast treatments. Local processes have been created for the standard assessment of head and neck treatments at fraction 14(where most shape change was shown) and for the first fraction of all breast
IMRT treatments, where most changes in seroma were seen. The additional
service workload requirements were easily adopted into clinical practices.
References:
1. International Commission on Radiation Units and Measurements. Prescribing, Recording, and Reporting Photon Beam Therapy (Report50). Bethesda: International Commission on Radiation Units and Measurements (ICRU); 1993.

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FEASIBILITY OF DOSE DIFFERENCE ASSESSMENTS FOR
ADAPTIVE RADIOTHERAPY IN ROUTINE PRACTICE WITH TOMOTHERAPY
D. Routsis1 , J. Dean1 , J. Fairfoul2
1
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Radiotherapy Department, Cambridge, United Kingdom
2
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Cambridge, United Kingdom
Purpose: The goal of radiotherapy is to deliver planned radiation doses precisely where needed; as such, the ability to confirm the exact position andmagnitude of the dose received inside each tissue would be beneficial. Oneof the functionalities of TomoTherapy is the ability to export MV CT scans
into the planning system, whereby the dose distribution can be recalculated
based on actual treated anatomical positions. The dose distribution received
can be compared to that planned, quantifying any dose differences. Patientswhere significant dose differences occurred could be identified and their treatment adapted to their needs (adaptive radiotherapy). This study aimed toinvestigate the feasibility of integrating these procedures into routine clinicalpractice.
Materials: Adaptive assessment procedures were implemented locally in
April 2010, following physicists, radiographers and dosimetrists training. Criteria were created for identifying patients thought to require dose evaluations, based on current published evidence. Categories were: external shapechanges ; internal structure shape, size or position changes seen on MVCT
; unexpected treatment toxicities; poor positional reproducibility; first fraction
margin checks (when using virtual bolus or plan dose constraints are narrowly achieved ); trends previously seen (shape changes, dose differences);
after unplanned gaps in treatment; other. The data was analysed for clinicalneed by assessing the number of occasions planned dose parameters were
exceeded outside of international recommendations. The need for replanning took into account the position of the dose variation and was a clinicaljudgement based on individual patient needs.
Results: From 28/4/10 to 15/12/10, 85 out of 236 patients (36%) had dose
assessments following the criteria specified. This equated to 2% (169/8030)
of all IMRT fractions. 90% were head and neck treatments, 6% breast and
3% prostate. 68% were due to changes in external contour of the patient.
Dose differences are shown in table 1. 4 patients were replanned as a resultof the adaptive requirement assessment (5% of patients fitting criteria, 2% of
all IMRT patients). Average staff time for each MVCT export dose evaluation
was 10 minutes.

2. International Commission on Radiation Units and Measurements. Prescribing, recording and reporting photon beam therapy (Supplement to
ICRU Report 50),: International Commission on Radiation Units andMeasurements; 1999.

258 oral
PROBABILISTIC PLANNING REDUCES NORMAL TISSUE COMPLICATION PROBABILITIES IN PROSTATE IMRT PLANS
J. Gordon1 , J. Siebers1
1
V IRGINIA C OMMONWEALTH U NIVERSITY, Department of Radiation
Oncology, Richmond, VA, USA
Purpose: Probabilistic treatment planning has the potential to reduce normal tissue complication probabilities (NTCPs) in IMRT plans, by eliminating
conventional planning target volumes (PTVs) and instead compensating for
setup errors and organ motion by directly optimizing the treated volume aspart of inverse planning. This work quantifies NTCP reductions in 10 IMRT
plans for localized prostate cancer.
Materials: Inter-fraction setup errors are modeled as normally distributedwith standard deviations Σ (systematic) = σ (random) = 3mm. Intra-fraction
motion is not modeled. IMRT optimization is performed using dose-volume
constraints from the high dose arm of the RTOG0126 protocol. The prostateprescription dose is 79.2Gy, and RTOG0126 D15, D25, D35 and D50 tolerance doses are applied to the rectum and bladder. PTV-based plans are
generated with a uniform 1cm PTV margin. Based on the simplified treatment model underlying the van Herk margin formula, a 1cm margin ensuresthat the clinical target volume (CTV) receives the prescription dose for 95%
of treatment courses. For probabilistic planning, traditional dose-volume constraints of the form Dv > d (for the PTV) and Dv < d (for organs at risk (OAR))
are replaced with probabilistic optimization criteria of the form Pr[Dv > d] ≥q (for the CTV) and Pr[Dv < d] ≥ q (for OAR), where q = 95% is referred
to as a coverage probability. Using novel objective functions, probabilisticplans are optimized to meet the probabilistic criteria. Plans are evaluated using conventional (static) dose volume histograms (DVHs), probabilistic DVHs
(PDVHs), tumor control probabilities (TCPs), NTCPs, and the probability ofcomplication-free control: P+ = TCP * (1 NTCPrectum) * (1 NTCPbladder).
TCP is calculated using the Poisson model with published parameters for intermediate risk cancer. Rectum NTCP is calculated according to QUANTEC
recommendations, the modeled endpoint being grade ≥2 late rectal toxicity. Bladder NTCP is calculated with the LKB model and plausible parametervalues, the modeled endpoint being grade ≥2 late bladder toxicity.
Results: Probabilistic plans have comparable TCPs to PTV-based plans, withaverage TCP for both types of plan around 85%. Probabilistic plans reducehigh-end doses to the rectum and bladder, and therefore reduce NTCPs andincrease P+ values relative to PTV-based plans. Rectum NTCP reductions
range from 0% to 10.6% (mean of 4.5%). Bladder NTCP reductions range
from -2.5% to 5.1% (mean of 2.5%). P+ increases range from 3.2% to 7.6%
(mean of 5.1%).
Conclusions: In conventional IMRT planning, PTVs function as intermediate helper structures to generate an acceptable treated volume. By eliminating PTVs, and instead directly optimizing the treated volume, probabilistic

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planning can improve the therapeutic ratio in plans where target dose is constrained by normal tissue tolerance doses.

T UESDAY, M AY 10, 2011

Award lectureAward Lectures
259 speaker
THE TRUTH ON PERMANENT PROSTATE BRACHYTHERAPY
J. J. Battermann1
1
U NIVERSITY M EDICAL C ENTER U TRECHT, Radiation Oncology, Utrecht,
Netherlands
Permanent prostate brachytherapy (PPB) became a serious treatment modality for localized prostate cancer after the publication of Holm in 1973 on perineal implantation guided by ultrasound. This technique was soon adopted
by centres over the world and promising results were reported in literature.
In the past thirty years there was a significant improvement in staging withprostate specific antigen (PSA), Gleason score and imaging with ultrasonography and MRI. However, PPB is still less common than prostatectomy. Whyis that, apart from the fact that surgeons are trained to operate and like to dothat?
Follow-up after PPB is not yet mature, although recently several papers were
published with experience of 10 and more years. After prostatectomy patients in general are only followed for five years or even till PSA is lower than
0.1ng/ml. Unfortunately, even after a long period or such a PSA value laterecurrences are found after both surgery and radiotherapy. Since the natural
history of prostate cancer is protracted in the majority of patients, outcome isoften stated as biochemical disease free survival (bDFS). PSA decrease isslow after PPB and may take 5 years or more to reach PSA nadir <0.1ng/ml.
Overall survival (OS) is not a good end point because many men will dieof cardiovascular disease and not of prostate cancer. In low risk patients(T1c-2c; PSA <10ng/ml; Gleason sum <7) results are similar after permanent
brachytherapy and surgery in several studies, although never proven by randomised studies.
Also for medium risk patients (T1c-2c; Gleason 7; PSA 10-20ng/ml) goodresults are described by different authors. We showed an improvement inoutcome for medium risk patients in the past decade compared with earlier
experience in our centre, but not for low risk patients. One should keep inmind that definition of intermediate risk cases is different from series to series and treatment may be combined with external beam radiotherapy (EBRT)
and/or androgen deprivation therapy (ADT). There are conflicting results inliterature concerning the results in Gleason 3+4 and 4+3 for all treatment
modalities. Looking at prostate cancer specific mortality for Gleason 3+4 and
4+3 after surgery and radiotherapy an increased risk of tumour progression
and specific mortality was found in those with Gleason 4+3 versus 3+4. In
another series of 530 patients with Gleason 3+4 or 4+3 at 10 years primary
Gleason score did not impact survival, while death from cardiovascular disease or second malignancies were 9.6 times more common than death fromprostate cancer.
The introduction of stranded seeds gave us more homogeneity in dose distribution and less seed loss, but comparative studies could not yet show adifference between strands and loose seeds. However, we found with anafter-loading technique using loose seeds not only a better dose distribution
than with stranded seeds, but also a better clinical outcome.
High risk (T3; Gleason >7; PSA>20ng/ml) patients have a significant lower
cure rate because a substantial number of them have microscopic metastases. In controlling local disease HDR brachytherapy can be used, either
alone or in combination with EBRT and/or ADT. There are studies indicatingthat HDR monotherapy in low- and medium-risk patients is feasible. That may
be true, but follow-up time of more than 10 years is not yet available. And often 3 fractions are used, with the possibility of needle displacement during
the interval.
Data in literature shows that outcome after PPB in patients before sixty yearsof age is at least as good as in older patients. But also in men over 74 yearsof age high rates of cause-specific and biochemical progression- free survival
after PPB are reported, while in general older men are considered not to be
candidates for prostatectomy.
It is well known that radiation may induce cancer, but data are presented,
showing an increase in secondary primary cancer (SPC) after EBRT of theprostate. We recently assessed SPC risk after I-125 prostate brachytherapy compared to prostatectomy in a cohort of 1,888 patients treated withbrachytherapy or prostatectomy from a Dutch data base and found no difference. But, at longer follow-up patients ≤60 years had a significant increased
risk of bladder cancer as was found earlier in patients after surgery or EBRT.
Never the less, the Commission on Radiological Protection considers the riskof SPC after PPB negligible.
Of course, results of PPB cannot be much better than surgery, but in experienced hands toxicity after brachytherapy is much lower than after surgery.
Quality of life six years after PPB was similar to base line, as was recently
presented from our centre. Up till now there is no indication that robot assisted laparoscopic prostatectomy will ensure a higher cure rate than open
surgery, nor will it lower the complication rate. Brachytherapy was associatedwith higher urinary function, bother scores and sexual function compared toopen and Da Vinci prostatectomy.
MRI gives the opportunity to better visualise tumour areas in the prostate.
This can be used to select patients for focal brachytherapy and hence further reduce side effects. As was proven by our team in a pilot study with

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local recurrences after previous radiotherapy on the prostate, patients withfocal brachytherapy had significant lower complications than patients treatedon the whole gland. For focal therapy only low risk patients with a single defined tumour might be candidates. On the other hand, in a German study of
243 men with low-risk localized prostate cancer after prostatectomy, despite
unilateral stage at biopsy, bilateral or even non-organ-confined cancer was
reported in 64% of all patients. The authors state that this alarming finding
questions the safety and validity of hemiablative therapy.
In conclusion we can state that PPB is at least equal to surgery and therefore
should be part of the armamentarium for low- and intermediate-risks prostatecancer patients. Excellent long-term biochemical disease free survival for
low- and intermediate risk patients is mentioned in papers from many series
worldwide. Quality of life after PPB is, also after 6 six years, not compromised.
260 oral
UNDERSTANDING XEROSTOMIA: THE ROLE OF MRI TO VISUALIZEEARLY RADIATION-INDUCED CHANGES IN SALIVARY GLANDS
A. Houweling12 , T. Schakel1 , M. Philippens1 , J. M. Roesink1 , C. Terhaard1 ,N. Raaijmakers1
U NIVERSITY M EDICAL C ENTER U TRECHT, Radiation Oncology, Utrecht,
Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands

1

Purpose: Reduced saliva production, xerostomia, is a major side effect of
RT in patients with head-and-neck cancer. The goal of this study was toinvestigate radiation-induced changes in the salivary glands, early after RT,
in detail using MRI.
Materials: Fourteen oropharyngeal cancer patients were treated with salivary gland sparing IMRT. All patients received a 3T MRI exam (Achieva,
Philips Healthcare) before and 6 weeks after RT. Patients were scanned intheir immobilization mask to reduce motion artifacts, using laterally located
Flex M coils. All patients received stimulated salivary flow measurements using Lashley cups. The imaging protocol consisted of a T1-weighted (TR/TE= 697/15 ms), a T2-weighted (TR/TE/TSE = 4200/130 ms/15), and a dynamic contrast-enhanced (DCE) (TR/TE/flip angle = 4.0/1.0 ms/13o ) MRI.
The DCE-MRI consisted of 45 acquisitions of 2.0 s each and the contrast
agent (Gadovist, Schering AG) was administered after 2 acquisitions with aninjection rate of 2 cc/s using a power injector (Spectris Solaris EP, MEDRAD
Inc.). The DCE-MR images were converted to contrast agent concentration
images and the extracted concentration-time curves were fitted to the Tofts
model to evaluate tissue perfusion (Ktrans , kep, vp, and ve). For both time
points separately, the parotid and submandibular glands were delineated on
the MR images. The signal intensities of the T1- and T2-weighted images
were normalized to the average brain intensity, that received a low RT dose.
Differences in volume and median signal of the glands were tested for significance using a Wilcoxon signed-rank test. Spearman’s rank correlation
coefficients were calculated between the MR changes and the RT dose andsalivary flow.
Results: The volume of the glands reduced significantly with 9.2 mL for theparotid and with 1.9 mL for the submandibular gland. The salivary flow reduced on average 60%.The median T1 signal reduced in both glands about
12%, while the median T2 signal significantly increased with 26% on average. The perfusion parameters vp and ve increased, and kep decreased
significantly in both glands. A correlation of the changes with the dose wasfound for the salivary flow in the parotid gland (R=0.7) and in both glands
for the change in T2 signal (R=0.6, Figure). Secondly, the reduction in submandibular volume is correlated to the increased ve (R=-0.6), which might be
an indication of cell loss.

Conclusions: Radiation-induced changes, early after RT, were observed in
the parotid and submandibular gland using MR. The observed differences indicated tissue loss and an increased water content such as found in edema.
This increased water content might be due to the observed reduction in perfusion. The changes could be related to the RT dose, but not to the salivary
flow. The changes in MR will reveal more insight on the underlying mechanisms causing radiation-induced xerostomia and MRI might be used as an
early indicator for salivary gland disfunction at the late stage.
261 oral
RADIOTHERAPY WITH UNFLATTENED PHOTON BEAMS: DOSIMETRIC ACCURACY OF TREATMENT PLANNING SYSTEMS
G. Kragl1 , D. Albrich1 , I. Fotina1 , D. Georg1
1

M EDICAL U NIVERSITY OF V IENNA, Department of Radiotherapy, Vienna,
Austria

Purpose: The aim of this study was to compare the dosimetric accuracyof advanced dose calculation algorithms for flattened (FF) and flattening filter
free (FFF) photon beams. Due to reduced variation of scatter factors with fieldsize and less pronounced off-axis softening for FFF beams, we hypothesizethat calculation accuracy might increase.
Materials: Two dose calculation algorithms were compared: the enhanced
collapsed cone (eCC) algorithm implemented in Oncentra Masterplan (v3.2)
and the XVMC Monte Carlo (MC) code implemented in Monaco (VSM 1.6).
Beam data of 10MV photon beams provided by an Elekta linac with and without FF were acquired and implemented into both TPS. Test cases comprised
single beam arrangements, composite conformal and IMRT plans. Measurements were performed with ion chambers, radiochromic films in a solid waterslab phantom and the heterogeneous CIRS Thorax phantom, as well as using 2D diode arrays (Delta4). Single beam tests were applied to the solid
water and CIRS phantom. Conformal plans and three IMRT plans (prostate,gyn, H&N) were delivered to Delta4. Dosimetric evaluation included absolute
dosimetry, and 1D g-evaluation of on- and off-axis PDDs and lateral profiles.
For single beam tests g-criteria of 2mm DTA and 2% dose deviation were applied; for composite treatment plans 2D/3D g-evaluation was performed with
3mm and 3%.
Results: Absolute dosimetry performed in the heterogeneous CIRS phantom revealed superior results for the MC algorithm with median absolute deviations between calculated and measured doses of 1.1/1.0% (FF/FFF) compared with 1.7/2.6% (FF/FFF) for eCC. For the 1D g-index evaluation, gmean
and gmax values were calculated for 36 line profiles for each algorithm andlinac mode acquired with EBT2 films in the solid water phantom. For MC
average gmean values were 0.53±0.28/0.46±0.22 for FF/FFF beams. The
respective values for eCC of 0.42±0.27/0.38±0.26 were significantly lower(p<0.05). gmax was on average by a value of 0.4 lower for eCC comparedto MC. When comparing the performances of the algorithms between FF and
FFF beams by means of average gmean values, MC revealed significantly
improved results for FFF beams. Considering off-axis profiles separately, we
found significantly reduced average gmean values for FFF beams for bothalgorithms (MC: 0.55±24 vs. 0.45±0.21, eCC: 0.41±0.24 vs. 0.35±0.22).
No significant difference was detected on-axis. All conformal/IMRT plans delivered to the Delta4 system showed similar verification results for FF and FFF
beams and met the acceptance criteria with >95% of the points within g≤1.
Conclusions: The investigated algorithms demonstrated accurate dose calculation for both FF and FFF beams. In the heterogeneous phantom MC

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performed better compared to eCC. Improved results of off-axis profiles of
FFF beams for single fields did not directly translate into higher accuracy ofcomposite plans, which might not be resolved due to the experimental uncertainty.
262 oral
A COVERAGE PROBABILITY BASED METHOD TO ESTIMATEPATIENT-SPECIC SMALL BOWEL PLANNING VOLUMES FOR USE
IN RADIOTHERAPY
L. B. Hysing1 , M. Söhn2 , L. P. Muren3 , M. Alber4
1

H AUKELAND U NIVERSITY H OSPITAL, Department of oncology and medical
physics, Bergen, Norway
L.-M AXIMILIANS -U NIV., K L . G ROSSHADERN, München, Germany
3
A ARHUS U NIVERSITY H OSPITAL, Aarhus C, Denmark
4
K LINIK FÜR R ADIOONKOLOGIE DER LMU, München, Germany
2

Purpose: The aim of this work was to develop a radiotherapy planning concept for the small bowel (SB) which has a high sensitivity in predicting SB
voxels and is specic, meaning that it does not contain many voxels which will
never be visited by SB.
Materials: Our method considers the variability in SB wall (SBW) position
between a number of CT-scans (registered on bony anatomy) and uses thisto estimate a ’soft margin’, such that patients with a mobile SBW would get abroader margin than patiens with a less mobile SBW. The ’soft margin’ is used
to estimate a coverage probability (CP) matrix from where planning organ-atrisk volumes (PRVs) are generated by applying various CP-thresholds. The
PRVs generated from 2-5 CT-scans were evaluated by their sensitivity andspecicity with respect to the PRVs from all 10-11 CT-scans in three patientswith different degrees of SB motion. Furthermore, the PRVs generated for
CP=0.005 (i.e. generous patient-specific PRVs) and for CP=0.03 (i.e. tightpatient-specific PRVs) were compared to an intestinal cavity (IC) approachand a population based PRV approach of 10mm and 30mm isotropic planning margins around SB. This was performed by repeated estimates of theoverlap between the planning volume in question and a randomly chosen
independent SB- /SBW volume as well as by comparing relative planning volumes (i.e. the volume relative to a boundary composed from the hull of allavailable ICs of the patient in question).
Results: The sensitivity and specicity of the PRVs depends on the numberof CT- scans and the CP-threshold. With three CT-scans and a thresholdof 0.03, an average sensitivity of 94-96% and specicity of 86-97% was obtained. The generous patient-specic PRVs and the 30mm margin approach
had an average overlap of >99% of both SB and SBW. The average overlap of SB/SBW for the tight patient-specific PRVs ranged from 92% to 99% ,for the ICs from 92% to 100% and for the 10mm margin from 89% to 98%.
The tight patient-specific PRVs and the 10mm margins had the lowest relative
volumes, followed by the generous patient-specific PRVs, the 30mm margins
and the ICs.
Conclusions: Based on a few CTs, our method generates patient-specic
SB PRVs which are highly sensitive and specic. Compared to conventional
approaches, the patient-specific PRVs are either similar or better in predicting
for SB voxels, and at the same time they occupy a smaller or similar volume
in the patient.
263 oral
TEMPORAL CHARACTERISATION AND IN-VITRO COMPARISONOF CELL SURVIVAL FOLLOWING DELIVERY OF 3D-CONFORMAL,INTENSITY MODULATED RADIATION THERAPY (IMRT) AND
VOLUMETRIC MODULATED ARC THERAPY (VMAT).
C. Mc Garry1 2 , K. Butterworth2 , C. Trainor2 , J. O’Sullivan2 3 , K. Prise2 , A.
R. Hounsell1 2
R ADIOTHERAPY P HYSICS , N ORTHERN I RELAND C ANCER C ENTRE ,B ELFAST H EALTH AND S OCIAL C ARE T RUST, Belfast, United Kingdom
2
C ENTRE FOR C ANCER R ESEARCH AND C ELL B IOLOGY, Q UEENSU NIVERSITY B ELFAST, Belfast, United Kingdom
3
C LINICAL O NCOLOGY, N ORTHERN I RELAND C ANCER C ENTRE , B ELFAST
H EALTH AND S OCIAL C ARE T RUST,, Belfast, United Kingdom
1

Purpose: The aim of this work is to assess the variation in tumour dose
history for clinically relevant inverse planned IMRT and VMAT deliveries andcompare these to a conformal plan. Cell survival is analysed for each 3DCRT, IMRT and VMAT treatment technique following delivery of a clinically
relevant dose (3 Gy) to a cell monolayer and is compared to a series of single
uniform beams delivered over a longer time range for two cell lines.
Materials: A phantom was designed and implemented for delivery of treatment plans to cells in-vitro. Single beam, 3D-conformal radiotherapy (3DCRT) plans, inverse planned 5 field Intensity Modulated Radiation Therapy(IMRT), 9 field IMRT, single arc Volumetric Modulated Arc Therapy (VMAT)
and dual arc VMAT plans were created on a CT scan of the phantom to deliver 3 Gy to the cells and verified using a Farmer chamber, 2D ionisationchamber array and Gafchromic film. Each plan was delivered to a 2D ionisation chamber array to assess temporal characteristics of the plan including

T UESDAY, M AY 10, 2011delivery time, ’cells eye view’ over a 7.62 x 9.14 cm2 area of the chamber
and the effective fraction time, defined as the percentage of the total fraction
time where any dose is delivered to a specific point examined. Each plan wasdelivered to human prostate cancer DU-145 cells and normal primary AGO1522b fibroblast cells. Uniform beams were delivered to each cell line withthe delivery time varied from 0.5 minutes to 20.54 minutes.
Results: Effective fraction time was found to increase with a decreasing number of beams or arcs. Temporal characteristics varied widely between modalities. AGO-1522b cells exhibited a statistically significant trend towards increased survival with increased delivery time for uniform beam delivery. This
trend was not repeated when the different clinical delivery method were used.
Less sensitive DU-145 cells did not exhibit a significant trend towards increased survival with increased delivery time for either the uniform or clinicaldeliveries.
Conclusions: These results confirm that dose rate effects are most prevalent in more radiosensitive cells. Differences in absorbed dose rate histories
of techniques such as 3D-CRT, IMRT and VMAT may not allow direct interpolation of cell survival using data generated from uniform beam delivery over arange of treatment times.

T UESDAY, M AY 10, 2011

Symposium
Treatment of Intermediate-risk prostate cancer patients
264 speaker
SURGERY
T. de Reijke

S YMPOSIUM

S 105

266 speaker
PERMANENT SEED IMPLANTATION FOR INTERMEDIATE RISKPROSTATE CANCER: EXCLUSIVE VS. COMBINED TREATMENT
J. A. Polo Rubio1
1
H OSPITAL R AMON Y C AJAL, Radiation Oncology, Madrid, Spain
Abstract not received.

Abstract not received.

EU Projects: ARTFORCE and ULICE
265 speaker
RADICAL / ADJUVANT EXTERNAL BEAM TREATMENT
A. Bossi1
1
I NSTITUT G USTAVE R OUSSY, Radiarion Therapy, Villejuif, France
The treatment of localized prostate cancer remains controversial because of
the lack of conclusive randomized studies comparing outcomes of the different therapeutic options available. This is particularly true for intermediate risk
group of prostate cancer patients defined based on T stage (= T2b-c), initial
PSA ( 10 20 ng/ml) and bioptic Gleason score (7) for which radical prostatectomy (RP), External Beam Radiotherapy (EBRT) or Brachytherapy (BT), bothunder the form of permanent seeds or temporary high dose rate implant, arecurrently used with similar results in terms of oncologic outcomes. EBRT has
an established role in the management of intermediate prostate cancer but inorder to keep EBRT attractive to patients in a very competitive world such as
the uro-oncology one, several aspects of it need consideration by radiotherapists in the near future.
The impact of dose-escalation on treatment results has been confirmed for
all risk group and technology offers today several solutions in order to safely
deliver high doses to the prostate without significantly increasing organs at
risk toxicity. This can possibly best be achieved by carefully taking into account prostate displacements during the entire RT treatment course by targettracking systems and different methods are nowadays available in order toefficiently perform image guidance. Using higher than standard 1,8 2 Gy
daily fractions in hypofractionated or stereotactic-RT protocols will give us thepossibility to treat in very short overall treatment time (< 10 fractions) insteadof protracted, standard ones (8 weeks) and this will translate in unquestionable convenience advantages for at least a selected group of patients. The
integration of EBRT with hormones for the intermediate risk prostate cancergroup is particularly controversial: little doubts exist today about the need ofassociating long term hormonal treatment to EBRT for high risk patients andconversely, any clear evidence has been produced for low risk patients, but
for the intermediate category guidelines are still ambiguous and results fromwell-conducted phase III randomized trials are awaited in the near future.
Another issue that needs to be explored in clinical trials is the association
between EBRT and a brachytherapy boost (both with permanent low dose
implant and temporary high dose ones) : the feasibility and the advantages ofsuch strategies have been shown in several published monocentric patients
series, systematic reviews of available studies and in at least one randomized trial particularly for the intermediate risk group. Last but not least, a very
promising field of research for EBRT is related to the individual prediction ofhealthy tissues toxicity before irradiation. Constraints based on Dose-Volume
Histograms are only part of the story and new tools have been developed
and tested in order to take into account patient co-morbidities and individual
genetic profiles that could explain unexpected late toxicities. Finally, the management of intermediate risk prostate cancer patients should be based on areal multidisciplinary approach with the direct involvement of all professionals
and of the patient himself in the decision-making process.
Adjuvant EBRT refers to the irradiation of the prostatic bed both immediately
after radical prostatectomy (= pure adjuvant RT) when high risk features for
local relapse are found at the pathology report, or at a later stage in caseof a PSA rising at distance from PR (= salvage RT). The relative merits ofthese two strategies are still debated in the urological literature even after
the recent publication of three major randomized clinical trials involving morethan 1500 post-prostatectomy patients showing clearly a benefit in terms of
relapse free-survival and overall survival (at least for one of the trials) whencomparing immediate irradiation to nothing when positive post-op margins or
extra-capsular disease extension or seminal vesicles infiltration are found on
definitive pathology after RP. Concerns about the toxicity of immediate RT
are regularly raised by urologists who reluctantly refers patients for RT after
RP even when very high risk features for local relapse are detected despite
the fact that, in the three mentioned trials, any significant detrimental effect of
adjuvant RT on quality of life has been shown.

267 speaker
ARTFORCE: INDIVIDUALIZED AND SAFE RADIATION TREATMENT
C. Rasch1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
ARTFORCE (Adaptive and innovative Radiation Treatment FOR improving
Cancer patients treatment outcome) is an EU funded proect within the seventh framework programme. Participating centers are: Institut Gustav Roussy(F), Christie Hospital (UK), Institut Catalan de Salud (E), Karolinska Institut(S), Raysearch (S), Maastro (NL), Maastro innovations (NL), NKI (NL).
New drugs and advancements in technical possibilities have widened the possibilities for treatment of head and neck and lung cancer.
Aim of the project is to improve clinical outcome for patients with lung andhead and neck cancer by means of pre-treatment selection on treatment specific predictors, individualized dose escalation, adaptive radiotherapy, in vivo
dosimetry.
First techniques for quality assurance and adaptive radiotherapy will be developed for the partners. At the end of the project techniques will be available
for the community.
Two clinical trials will be performed within the consortium:
Lung cancer: Randomised trial comparing dose escalation to the FDG-PET
high uptake region versus a dose prescription to the delineated tumour only.
Head and neck cancer: Randomised trial comparing adaptive RT escalated
to 84 Gy and standard IMRT till 70 Gy combined with either cisplatin or an
EGFR inhibitor. Uptake of Zr89 labelled EGFR inhibitor in vivo will be tested
for its predictive value on treatment outcome.
Previously developed biomarkers and gene signatures will be validated on
the tumour biopsies.At the end of the project (2016):
The outcome of the trials and validation of the biomarkers will be presented.
A commercial product for 3D in vivo dosimetry will be available.
268 speaker
ARTFORCE CLINICAL TRIAL IN NSCLC: PET BOOST STUDY
W. van Elmpt1 , E. Damen2 , A. van der Salm1 , A. Lakeman2 , J. van der
Stoep1 , D. Eggels-Emans1 , M. Öllers1 , J. J. Sonke2 , J. S. A. Belderbos2 , D.
De Ruysscher1
1
D EPARTMENT OF R ADIATION O NCOLOGY (MAASTRO), GROW - S CHOOLFOR O NCOLOGY AND D EVELOPMENTAL B IOLOGY , Maastricht, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
Approximately 85% of all patients with lung cancer are diagnosed with nonsmall cell lung cancer (NSCLC), with about 35 % of them presenting withlocally advanced disease (large stage II and III tumors). Even with concurrent
chemo-radiation local failures remains high for these patients, with local progression free survival (LPFS) rates of about 30%. Local recurrences occur
predominantly at the primary tumour site and are related to overall survivalin this patient group. A new strategy by boosting the radiation dose inside
the primary tumour is currently pursued to aim increased local control of the
primary tumour site.
We have recently started a randomized phase II trial investigating the concept of radiation dose redistribution within the tumour based on pre-treatment
FDG-PET scans: the "PET boost trial". Eligible for this trial are, amongst othercriteria, patients with stage II-III NSCLC with a diameter of the primary tumour
4 cm, with a maximum Standard Uptake Value (SUVmax) 5 candidate for RT
or chemo-radiation with curative intent. This cohort will be randomized to receive the standard 66 Gy given in 24 fractions of 2.75 Gy with an integrated
boost to the entire primary tumour (Arm A) or, alternatively, with an integrated
boost to the 50% SUVmax area within the primary tumour (Arm B). Both for
arm A and B the normal tissue constraints remain the same, suggesting thatthe toxicity rate will not be affected. Primary endpoint is local progression freesurvival at 1 year.
In this presentation the methodological/trial design and technical frameworkthat is necessary to perform this randomized dose-painting trial will be presented. Concepts such as QA of functional imaging, standardized normal
tissue delineation, iso-toxic treatment design by dual-arm treatment planningS 106

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and feasibility of treatment plan delivery with increased dose levels to highPET-uptake regions within the primary tumour will be discussed.
269 speaker
ULICE –UNION OF LIGHT - ION CENTRES IN EUROPE: WORKINGFOR HADRONTHERAPY
R. Orecchia1 , R. Pötter2 , J. Debus3 , M. Dosanjh4
1
N ATIONAL C ENTER FOR O NCOLOGIC H ADRONTHERAPY, Milan, Italy
2
M EDICAL U NIVERSITY V IENNA , AKH, Vienna, Austria
3
U NIV. K LINIKUM H EIDELBERG, Heidelberg, Germany
4
E UROPEAN O RGANISATION FOR N UCLEAR R ESEARCH CERNThe ULICE project started in 2009 to address two different complementaryissues:1. The development of the appropriate instruments for high-performance
hadrontherapy, with particular emphasis on carbon ion therapy.
2. The need for intensive collaboration among the existing and planned
centres, as well as with the European hadrontherapy community atlarge.
ULICE is funded for four years by the European Commission with 8.4
million Euros and involves 20 European institutions coordinated by CNAO.
All the existing and planned European ion therapy facilities are involvedin the project, together with two research centres (CERN and GSI) and
two industrial companies (Siemens and IBA). The approach of ULICE to
hadrontherapy deals with all its aspects from medical physics to radiobiology,
from accelerators to particle beams. The experience being built up in
Heidelberg, Pavia and Marburg will help the development of hadrontherapy inEurope and will provide patients throughout Europe access to these centreswith treatment according to standardized protocols. In addition, other centres
planned in Europe which are due to start, will benefit from this experience.
The project consists of 3 pillars:
1. Joint Research Activities focused on the development of instruments
and protocols
2. Networking to increase cooperation between facilities and researchcommunities
3. Transnational access to allow access to hadrontherapy facilities to researchers wanting to perform radiobiological and physics experiments
as well as clinical studies.
Joint Research Activities
This pillar is coordinated by the Medical University of Vienna and focuseson improving the performance of hadrontherapy facilities through thedevelopment of various instruments, partly available, but to be further
adapted for this new and challenging form of radiotherapy. The JRA pillar willdeal with clinical issues such as:
1. developing novel adaptive treatment planning, including protocols thatcombine different types of irradiations;
2. identifying tumours whose treatment would be boosted by the use of
proton or ion beams instead of X-rays;
3. developing a computer assisted patient selection program accessible
to the whole European community interested in hadrontherapy; thiswill not only enable an efficient patient referral to the existing facilities,
but also allow to pursue the clinical research focused on tumours withspecific biological characteristics and/or critical location. These tools
will allow the different centres to optimize which radiation quality has
the best chance to cure specific tumours, and provide a research infrastructure producing scientifically sound evidence on the efficacy of
hadrontherapy. Among the technical issues that ULICE will address
through JRA is the challenge of reducing the dimensions and cost of
the gantries, the structures that bring protons and ions to the patient
allowing to target the tumour from multiple directions.
Networking Activities
The Networking Activities pillar is coordinated by CERN and focuses on:
1. Communication, interaction and interdisciplinary discussion amongthe 20 partners and with the external world
2. Dissemination of the project results to the wider community involved incancer care

T UESDAY, M AY 10, 2011
Networking activities will provide the external research community with a clear
knowledge of what is possible and what is needed in terms of research to be
carried out at the facilities (both through dissemination activities, residentialtraining for researchers and through scientific events and publications).
Transnational AccessThis pillar is coordinated by the University Hospital of Heidelberg, and aims
at providing access for external researchers to the ion therapy facilities forpreclinical research with the available beams of particles. Beam time will beallocated to the external researchers through a review committee, that will assess the scientific impact of the proposed research project. The Transnational
Access pillar will also produce agreed protocols for multi centric clinical trials,
and allow external researchers to participate in these trials. These goals will
be facilitated making an extensive use of advanced e-science grid technology.

T UESDAY, M AY 10, 2011

Symposium
ESTRO-ASTRO Joint symposium: How high precision technology will change our life
270 speaker
HIGH TECH RADIATION THERAPY: WHERE ARE THE LIMITS?
B. Slotman1
1
VU U NIVERSITY M EDICAL C ENTER, Radiation Oncology, Amsterdam,
Netherlands
Over the last few decades, the field of radiation oncology has gone throughimmense changes in technology and treatment concepts. From an era oftreatments using a few large fields, with heavy cerro bend blocks and wedges,
to a number of very small intensity modulated fields or volumetric modulated
arc treatment. Contouring on orthogonal X-rays or paper (or no contouring
at all) has been replaced by contouring using the concepts of GTV, ITV, CTV,
PTV, OAR and PRV delineated on fused CT, MR and PET scans. Single oronce weekly Megavoltage films were first replaced by more frequent electronic portal images and orthogonal KV imaging, later by combined KV-MV
imaging, cone-beam CT, fluoroscopy, and soon MRI will be available on the
linac as well. For moving targets and organs at risk, the standard, population based margins around the volumes have been replaced by individualized margins based on 4D information about motion. Crude estimates aboutnormal organ toxicity and tolerance doses have been better defined. Gating of the radiation beam is now available to limit radiation of mobile tumors
to specific phases of the respiratory cycle, and tracking of target volumes
has outgrown the experimental stage. High precision techniques have enabled the delivery of much higher doses per fraction and higher biologicallyeffective doses. Proton and particle therapy centers are booming business.
Modified conventional linear accelerators have been in use for radiosurgery
and stereotactic radiotherapy for more than 20 years. For various intracranial
indications, radiosurgery has become an alternative to surgery. The case formodern high-tech radiotherapy has really been made by the results of stereotactic body radiotherapy (SBRT). Small lung tumors which received doses of
60 Gy in 25-35 fractions are now treated to the same total dose but delivered in only three to five fractions. This has led to a dramatic improvementin outcome and the technique might become an alternative to surgery. In
other areas, such as head and neck cancers, high-tech radiotherapy has also
led to improved sparing of organs at risk with lower toxicity rates. In spite of
the increase in technology, treatment times have remained approximately thesame. Even complicated stereotactic treatments can nowadays be completed
within 20-30 minutes. Treatments which were considered as intensive or special only a decade ago, have become a normal part of the work load in many
departments. Specific linacs have now been developed for specific purposes.
The original linacs,were developed to only deliver radiation, and they have,over the years evolved into machines with multiple imaging capabilities. Recent developments promise better integration of radiation delivery and imaging functions, opening up new therapeutic avenues. Other specialties in thefield of oncology show an increasing awareness of the transitions taking placein radiotherapy and their potential. The use of systemic therapies with stereotactic radiotherapy for local ablation for example is challenging current conventions and in some cases redefining approaches to palliation and individual
patient treatments. Naturally, patients and medical teams wonder where thisall ends; where are the limits? Are there any limits?Every step in the processof high-tech radiotherapy has its limitations, but there is no reason to assume
that they cannot eventually be overcome. One important factor in improving
outcomes remains better selection of patients who might benefit the mostfrom a given treatment or require a special approach, and a greater ability
to personalize therapy. With high-tech radiotherapy, it is possible to deliver
the dose with a precision that is almost the same as the resolution of available imaging techniques. This means that one of the most critical factors has
become the delineation of the target volume. Numerous studies have shownconsiderable interobserver variation, and improvements are definitely needed
here. This can be achieved by training, intercollegial discussion of contouring,and possibly also with help from automated processes. The integration between irradiation and imaging may be further strengthened by improvements
in online imaging and is essential to exploit the significant shortening of thebeam-on-time that is now possible. New approaches to on-line image analysis and plan evaluation mean that the current chain from treatment planningto treatment delivery may disappear and be replaced by an iterative process
involving daily adaptation of the treatment plan and target volume. In the presentation, a number of the recent technological changes and possibilities for
future changes will be discussed. Technical, biological, logistical ,economical, educational and patient- and doctor-related factors which could limit the
future developments will be addressed.

S YMPOSIUM

S 107

271 speaker
TARGETING CONCEPTS: SPATIAL, MOLECULAR, PHYSIOLOGIC,TEMPORAL
T. Rich1
1
U NIVERSITY OF V IRGINIA, School of Medicine, Charlottesville, VA, USA
The advances in radiation oncology over the history of the field and indeed
over the last 30 years, has been driven largely by technical advances regarding tumor localization, radiation treatment planning, and high precision
therapeutic delivery techniques. Along with these advances has been a more
recent explosion in the biologic knowledge of tumors and normal tissues thatis being actively interwoven into new combination treatment options offered tothe patient with malignancy. In this presentation these treatment approaches
will be discussed in the context of multiple interventions: Spatial targeting:the use of new diagnostic and treatment planning and delivery techniques;
Biologic/molecular targeting: the use of receptor /signal transduction based
therapies and the use of rationally designed chemo- and bio-logic agents;
Physiologic targeting: the use of agents leveraging the "leakiness" and proliferative nature of tumor vasculature, and the consequence of hypoxia; Temporal targeting: the use of cytotoxic agents and irradiation techniques at thebest tolerated and most effective times. There is strong evidence that combinations of these targeting concepts has improved treatment results and thatthe continued study may improve outcomes further. Examples of where theseconcepts have been considered to be advantageous to the patient with malignancy will be presented with emphasis of the interaction between them. Illustrative examples from tumor sites including rectal, pancreatic, and prostatecancers, and brain metastasis will be discussed.
272 speaker
WHAT IS THE CLINICAL BENEFIT OF 4D ADAPTIVE RADIOTHERAPY?
C. Rasch1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
During radiation treatment patients and the tumour within the patients change.
Changes can be reproducible (e.g. breathing motion) or longitudinal (e.g. tumour response or parotid gland volume).
Non respiration correlated (4D) imaging often results in an incorrect pictureof the (lung) tumour. 4D imaging therefore increases the systematic error in
the treatment of lung cancer. Although no randomised trials are performed
to proof the clinical benefit reducing an important systematic error source like
improved imaging perse can be regarded a quality assurance tool.
Day to day variations in target position in the absence of target imaging require large margins (e.g. bladder, prostate and cervix uterus radiotherapy). It
is clear that with repetitive imaging and treatment plan adaptation, either froma treatment plan library or online treatment planning, less normal tissue willbe irradiated as the uncertainty in target position is smaller. Reduced rectal
irradiated volume results in lesser side effects. On top of that: Not performing
repetitive imaging can be dangerous. Data on prostate cancer have shownthat those patients with large initial rectal volumes and/or higher grades ofdiarrea had poorer local control.
Performing adaptive radiotherapy for longitudinal changes like ART for headand neck cancer is not clinically proven better than IMRT alone. In silico data
demonstrated the potential for better sparing of organs at risk. Adapting thetreatment fields on shrinking tumour can be dangerous as the shrinking of a
projected tumour boundary is most likely not the result of elastic regression
but rather a reduction of tumour density below the detectable threshold. Dataon head and neck cancer and lung cancer in this respect point in the same
direction.
273 speaker
ADAPTIVE TREATMENT WITH MOLECULAR IMAGING
D. Zips1
1

O NCO R AY, Dresden, Germany

Radiation and drug response of tumours and normal tissues varies widely
among patients. Understanding of molecular mechanisms underlying thisheterogeneity in response and technology to exploit this knowlegde from biological stratification towards therapeutic intervention is rapidly developing. As
a result, molecular imaging for biologically adaptive radiotherapy became amajor field of translational research activities. The clinical concept, strategies
for evaluation and clinical implementation will be discussed.

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Proffered paper
Clinical Proffered Papers 3: Lung Cancer
274 oralA PRACTICAL PREDICTION MODEL FOR OVERALL SURVIVALFROM STAGE III LUNG CANCER
C. Oberije1 , R. Houben1 , D. De Ruysscher1 , A. M. Dingemans2 , G.
Bootsma3 , W. Geraedts4 , C. Pitz5 , R. Lunde5 , P. Lambin1
M AASTRICHT R ADIATION O NCOLOGY (MAASTRO), GROW - S CHOOLFOR O NCOLOGY AND D EVELOPMENTAL B IOLOGY, U NIVERSITY M AASTRICHT ,Department of Radiotherapy, Maastricht, Netherlands
2
M AASTRICHT U NIVERSITY M EDICAL C ENTRE, Department of Lung
Diseases, Maastricht, Netherlands
3
ATRIUM M EDICAL C ENTER, Department of Lung Diseases, Heerlen,
Netherlands
4
O RBIS M EDICAL C ENTRE, Department of Lung Diseases, Sittard,
Netherlands
5
L AURENTIUS H OSPITAL, Department of Lung Diseases, Roermond,
Netherlands

T UESDAY, M AY 10, 2011
275 oral
INTRA THORACIC ANATOMICAL CHANGES FOR LUNG CANCERPATIENTS DURING THE COURSE OF IRRADIATION: HOW TORESPOND?
S. Conijn1 , J. Belderbos1 , J. Knegjens1 , M. Rossi1 , J. J. Sonke1 , P.
Remeijer1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

T UESDAY, M AY 10, 2011
cision protocol with clear guidelines on how to respond was developed containing three action levels that describe the urgency of taking action for the
RTT and the radiation oncologist. It is estimated that the radiation oncologist
needs to respond immediately in about 12% of the patients. We recommend a
decision protocol to be standard practice in any institution with a CBCT scan.
Decision rules on dosimetric criteria and adaptive interventions are subject ofadditional research.

1

276 oral1

Purpose: Most models regarding outcome of treatment for lung cancer are
prognostic in nature. Recently, a practical and validated prediction model forradiation-induced dysphagia has been published (Dehing-Oberije, 2010). We
aim to design a predictive model for overall survival for patients with stage IIIlung cancer.
Materials: Patient, clinical, treatment and survival data for 492 stage III (according to UICC version 6) lung cancer patients were available for analysis.
Patients were included in the analysis if they (1) were treated with radiotherapy with curative intent, (2) had not received surgery, (3) had no other tumours in the past 5 years and (4) patients with malignant pleurisy were excluded. A predictive model was developed using backwards Cox regression
analysis (excluding variables with p >.20) with R 2.12.0 and the Design library. The final model was internally validated using a 100 times bootstrap
procedure, to check whether variables were consistently selected. Potential
predictors for survival were gender, age (years), T (0, 1 or 2) and N-stage (0or 1-2), WHO-PS (0, 1 or 2), number of positive lymph nodes on PET (0, 1,
2, 3 or >=4), smoking status (never smoked or non-/ex-smoker), lung function(fev1%), chemotherapy (none, sequential or concurrent), gross tumor volume(GTV in cc), radiotherapy dose (Gy) and overall treatment time (days). Missing values were generally less than 10% and patients with missing values
had mostly 1 or 2 values missing. These values were replaced with regression based multiple imputation.
Results: Of all patients, 374 had died at the time of the analysis. Median survival time was 16 months. Backwards Cox regression of possible predictors
resulted in the elimination of age, N-stage, number of positive lymph nodes
on PET and smoking status from the model. Predictors for the final modelwith HR, p-value and 95% confidence interval are shown in table 1. GTV
could only be modeled non-linear, using restricted cubic splines with 3 knots.
Concordance statistic for the final model was 0.66.

Purpose: Cone beam CT (CBCT) guidance is routinely used for setup verification of lung patients in our clinic. CBCTs make us aware of intra thoracic
anatomical changes during the 5 week course of treatment. The radiation
technologist (RTT) and radiation oncologist are responsible for identifying
and responding on these changes. Clear protocols or guidelines, however,are currently lacking. The purpose of this study is to develop and validate adecision protocol for intervention.
Materials: A multi-disciplinary team defined three types of urgency levels.
Urgency level 1: "immediate action" include changes that may affect the tumor and/or lymph nodes position with respect to the PTV. These changes canbe caused by tumor growth, a large in- or decrease of atelectasis and focal increase of normal lung density, like post obstructive pneumonia. Urgency level
2: "No immediate action, inform radiation oncologist" includes minor in- or
decrease of atelectasis and pleural effusion. Urgency level 3: "Tumor regression" without considerable centre of mass displacement or other anatomicalchanges. For level 1 changes, the radiation oncologist needs to be consulted
immediately, as a new planning CT may be required. For level 2, the radiation
oncologist will be informed by email, no immediate decision is required. For
level 3, no action is required. The developed decision protocol was retrospectively evaluated on all lung cancer patients treated with curative intend fromJanuary 2010 until November 2010. For these patients repeat CBCT scans
were available.
Results: Over the period evaluated, 180 lung cancer patients were treatedwith Intensity Modulated Radiotherapy (IMRT). For a total of 83 patients(46%), intra thoracic anatomical changes were detected. 11 patients (6%)
required a new planning CT scan to adapt to the changed anatomy. Retrospectively, level 1 changes were observed for 12 % of the patients. Level 2
occurred in 27% of all patients. Finally, level 3 changes were observed in only
6% of the patients. From all three urgency levels, illustrative examples havebeen selected and included in the clinical protocol manual (figure 1). All RTTs
have been trained in using the urgency levels and the decision protocol has
been implemented clinically.

MEDIASTINAL LYMPH NODE POSITION VARIABILITY IN LUNGCANCER PATIENTS TREATED WITH RADIOTHERAPY
E. Schaake1 , J. S. A. Belderbos2 , J. Nijkamp2 , W. Buikhuisen3 , S. Burgers3 ,J. J. Sonke2
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
3
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Thoracic Oncology, Amsterdam, Netherlands
Purpose: Margins are required to account for inter- and intra-fraction position
variability and respiration induced tumor and pathologic lymph node motion
over the course of radiotherapy (RT). Detailed knowledge however, on thepositional variability of the lymph nodes relative to the bony anatomy (baselinevariation) and primary tumor (differential motion) is lacking. Therefore, thestandard margins used for the lymph nodes range from 1 to 1.5 cm. The
purpose of this study is to quantify mediastinal lymph node position variability
over the course of RT in lung cancer patients.
Materials: A medical ethical committee approved study was recently started.
Small 0.35mm by 5mm golden fiducial markers (Visicoil) were placed in atleast one lymph node station of non-small cell lung cancer (NSCLC) patientsduring a standard diagnostic trans-oesophageal endoscopic ultrasound fineneedle aspiration. For all patients a respiration correlated (RC) 4D planning
CT and daily 4D RC Cone Beam (CB)CT scans were acquired during radiotherapy (66 Gy/24 fractions). A 3D mid-position scan was reconstructedfrom the 4D CT-scan and used as planning CT. All CBCT scans were firstregistered based on bony anatomy to the planning CT. Each scan was subsequently registered frame by frame to the planning CT based on grey-value
registration using a shaped region of interest around the implanted fiducial
marker. Each registration was visually assessed using the fiducial. The rangeof motion of the fiducial for each 4D CBCT scans quantifies the motion amplitude due to breathing. Differences between the bony anatomy- and theaverage 4D fiducial location were used to calculate the systematic and random base-line variations of the lymph nodes.
Results: Five patients were included so far with a total of 6 fiducials placed
in lymph node stations 2L (1), 4L (1), 5 (1) and 7 (3). A total of 146 4D-CBCT
scans were registered. Table 1 lists the results relative to bony anatomy.

Conclusions: Using implanted fiducials we have shown that geometric uncertainties for mediastinal lymph nodes relative to the bony anatomy of
NSCLC patients are substantial. Currently used margins seem to be sufficient for an online protocol. More patients will be included to increase thestatistical power for the remainder of this analysis. The geometric uncertainties were predominantly in cranial-caudal direction, indicating the non-uniform
margins could be beneficial. When on-line tumor position correction is used,
the lymph node variability will possibly be even larger.
Conclusions: The predictive model for overall survival of stage III lung cancer patients highlights the importance of patient, clinical and treatment variables. This model can provide valuable information in determining the best
course of treatment for individual patients. A nomogram for prediction of
overall survival will be presented.References: Dehing-Oberije C, De Ruysscher D, Petit S, Van Meerbeeck J, Vandecasteele K, De Neve W, Dingemans
AM, El Naqa I, Deasy J, Bradley J, Huang E, Lambin P. Development, external validation and clinical usefulness of a practical prediction model forradiation-induced dysphagia in lung cancer patients. Radiother Oncol. 2010
Dec;97(3):455-61.
Conclusions: Clear intra thoracic anatomical changes have been observedin almost 50% of all lung cancer patients treated with curative intend. A de-

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277 oral
ADJUVANT RADIOTHERAPY AFTER EXTRAPLEURAL PNEUMONECTOMY FOR MESOTHELIOMA. PROSPECTIVE ANALYSIS OF
A MULTI-ISTITUTIONAL SERIES
S. Tonoli1 , V. Scotti2 , F. Bertoni3 , F. Saiani4 , L. Spiazzi4 , F. Banci
Buonamici5 , P. Bastiani6 , L. Marrazzo5 , I. Meattini2 , M. Amichetti7 , M.
Schwarz8 , G. Guidi3 , P. Hammer7 , S. Magrini91
B RESCIA U NIVERSITY, Department of Radiation Oncology, Brescia, Italy
2
AOU C AREGGI, Firenze, Italy
3
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Modena, Italy
4
S PEDALI C IVILI DI B RESCIA, Department of Medical Physics, Brescia, Italy
5
C AREGGI H OSPITAL, Firenze, Italy
6
O SPEDALE S ANTA M ARIA A NNUNZIATA F IRENZE, Bagno a Ripoli, Italy
7
AT RE P, AGENZIA P ROVINCIALE PER LA P ROTONTERAPIA, Trento, Italy
8
AGENZIA P ROVINCIALE PER LA P ROTONTERAPIA, Trento, Italy
9
S PEDALI C IVILI DI B RESCIA, Brescia, Italy
Purpose: to evaluate survival, loco-regional control and toxicity in a series of
51 Mesothelioma patients treated in three Institutions (Brescia, Florence andModena) from May 2005 to May 2010 with post-operative radiotherapy after
extrapleural pneumonectomy.
Materials: 57 patients were identified (47 males and 10 females, 32 casesright site, 25 left site). The histology was epithelioid in 84.2% of cases (biphasic in the remaining 15.8 %). Mean age was equal to 58 years (range 36-77).
Four cases were stage I, 12 stage II, 32 stage III and the remaining 9 stage
IV. Four patients were treated with 3DCRT, 51 with IMRT and 2 with helicaltomotherapy. Eighteen patients were submitted to neo-adjuvant chemotherapy (usually 3-4 cycles CDDP/pemetrexed). In 30 cases a dose of 50 Gy
in 25 fractions was given to the hemi-toracic space and the ispilateral mediastinum. In 18 cases a simultaneous integrated boost has been given to thesites of positive margins as evident in the pathologic examination (60 Gy in
25 fractions). Twenty five patients received adjuvant chemotherapy (usually
2-3 cycles CDDP/pemetrexed).
Results:

Univariated analysis shows a negative influence of neo-adjuvant chemotherapy on LRC (p 0.014) and DFS (p 0.045). There was also a trend for better
DMFS (p 0.07) with neo-adjuvant chemotherapy and better DFS (p 0.07) andLRC (p 0.07) with adjuvant chemotherapy.
An acute toxicity of 2-3 degree (according to the CTCAE v.3 scale) was
pointed out in 26.1% of patients (fatigue), 17.8% (dysphagia), 13.1% (dyspnoea), 6.7% (esophagitis), 20% (nausea), 13.3% (vomiting).A late toxicityof 2 degree (according to the CTCAE v.3 scale) was pointed out in 3.7%of patients (fatigue), 3.7% (pain), 3.7% (dysphagia), 7.1% (dyspnoea), 3.7%
(esophagitis).
One patient died for constrictive pericarditis 3 years after the treatment (it is
not known if related with radiotherapy). Another patient died during radiotherapy for pulmonary embolism.
Conclusions: The results are encouraging even if the patients sometimes
need hospitalization during the treatment for acute toxicity. The result in termof locoregional control are good despite the difficulty to obtain an adequate
inclusion of the lower portion of target in the 95% of prescribed isodose (inmost cases treated with IMRT).
278 oral
DOSE ESCALATION USING 3DCRT IN CONCURRENT SETTINGWITH VINORELBINE AND A PLATINUM COMPOUND IN LOCALLYADVANCED NSCLC
P. Rusu1 , T. E. Ciuleanu23 , N. Todor4 , T. Guttman5 , V. Bogdan1 , V.
Cernea21
1
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Radiotherapy,
Cluj-Napoca, Romania
2
U NIVERSITY OF M EDICINE AND P HARMACY "I ULIU H ATIEGANU ", Medical
Oncology and Radiotherapy, Cluj-Napoca, Romania
3
O NCOLOGY I NSTITUTE "P ROF.D R . I ON C HIRICUTA ", Medical Oncology,
Cluj-Napoca, Romania
4
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Biostatistics,
Cluj-Napoca, Romania
5
O NCOLOGY I NSTITUTE "P ROF.D R . I ON C HIRICUTA ", Radiology, ClujNapoca, Romania
Purpose: In order to improve local and distant control, we aimed to evaluate the maximum-tolerated dose (MTD) and efficacy of dose escalation using three-dimensional conformal Radiotherapy (3DCRT) in concurrent setting

S 110P ROFFERED PAPER

with vinorelbine (Vrb) and Cisplatin (DDP) or Carboplatin (CBDCA) in locallyadvanced non-small cell lung cancer (NSCLC).
Materials: Sixty two patients (pts) were included from 09.02.2005 to
16.12.2009 with median age 58.5 (41-74), M/F=57/5, PS 1/2=43/19, stage
IIIA/IIIB=11/51, squamous cell cc 48, large cell cc 2, adenocc 8, non-small"carcinoma 4. Patients who fulfilled the dose-volume histogram constraints,
underwent dose escalation of radiotherapy, if no more than two grade 3 or
one grade 4 toxicities occurred, until MTD. If there were one grade 3 and one
grade 4 toxicities, further expansion continued by 6 more pts. Chemotherapy
consisted of 6 cycles of Vrb (25 mg/sqm, d1, 8, q21) and DDP (100 mg/sqm,
d1, q21), or CBDCA (AUC 5, d1, q21), In concurrent setting, doses were reduced: Vrb 15 mg/sqm, d1, 8, q21, DDP 80 mg/sqm, d1, q21 or CBDCA AUC
4, d1, q21.
Results: Fifty five pts underwent dose escalation in seven cohorts from 64Gy
to 76Gy without dose-limiting toxicity. For each dose level up to 7 pts wereenrolled, with further expansion by 6 pts at 70 Gy dose level.Acute toxicities, in the 62 evaluable pts, were preponderantly mild, of grade 1 and 2.
Severe acute grade 3 and 4 toxicities were: esophagitis in 6 (10%), pulmonary toxicity in 7 (11%), neutropenia in 14 (22%) pts. The preliminary
results showed an objective response rate of 82%. With a median follow-up
of 25.8 months, median survival was not reached yet, the 1 and 2-year survival rates were 87% and 56% ( CI 43%-69%). Progression free survival at 1
year was 61%, at 2 years 30% (CI: 20%-43%) and mTTP 13.9 months. Locoregional progression- free survival at 1 year was 76%, at 2 years 42% ( CI:
29%-56%).
Conclusions: As no MTD was reached during dose escalation this strategy
has to be continued. RR and Survival data were promissing.
279 oral
RADIOCHEMOTHERAPYFOR
LOCALLY-ADVANCEDNSCLC:
WHICH IS THE BEST ASSOCIATION? FROM CHEMOTHERAPY TO
BIOLOGICAL TARGET IN 5 PHASES II TRIALS
S. Ramella1 , R. M. D’Angelillo1 , F. Cellini1 , M. Fiore1 , E. Ippolito1 , E.
Pompeo2 , T. C. Mineo2 , L. Trodella1
1
U NIVERSITA C AMPUS B IOMEDICO, Radiotherapy and Oncology Unit,
Roma, Italy
2
TOR V ERGATA U NIVERSITY, Thoracic surgery, Rome, Italy
Purpose: Radiotherapy and concurrent chemotherapy is actually the standard of care in locally advanced NSCLC even if the optimal regimen of association is still a matter of discussion. Actually, the question of "the right drugfor the right patients" is an emerging topic in oncology. In metastatic NSCLC,
it was largely demonstrated the correlation between drugs activity and histology with some agents more active in squamous cell carcinoma (Gemcitabine)and others in non-squamous one (Pemetrexed)1 . But, in locally advanced
disease, in association with optimized radiotherapy is the same algorithm stilltrue? We report the results of 5 phase II trials exploring the impact of histology on the activity of different drugs concurrent to radiation from old to third
generation drugs, until administration of target therapies.
Materials: 294 patients with histo-citologically confirmed NSCLC were enrolled into 5 phase II trials (A-E) of combined chemo-radiation. Optimized
involved field Radiotherapy was always delivered up to radical or neoadjuvant dose (59.8Gy or 50.4Gy, respectively), with daily fractionation of 1.8
Gy. Concurrent chemotherapy changed during time: from platinoid and5-FU1 to weekly gemcitabine2 associated or not with previous induction
chemotherapy3 ; then with the administration of concurrent cisplatin andgemcitabine4 and finally with TKI target therapy (erlotinib) with pemetrexed
or gemcitabine.Pulmonary, esophageal, hematological, gastrointestinal andskin toxicities were assessed during treatment and follow-up . Adverse
events were recorded according to RTOG or NCI Common Toxicitity Criteria 3.0 scales. Clinical response was evaluated 4-5 weeks after the end ofradiochemotherapy by CT scan with or without PET/TC 18 FDG.
Results: Patients were selected in squamous (SCC) and non-squamous cell
carcinoma (Non-SCC) (adenocarcinoma, large cell and NOS) according tohistology. In neoadjuvant trials (A-B-C) treatment consisted in old or third
generation drug (gemcitabine-GEM). Median survival was 18.3 months. SCC
patients survival was correlated to radiotherapy associated drug with a trend
in favor of GEM-group versus non-GEM one (28.4 vs 17.2 months; p= 0.06),
as expected from recent trials in metastatic patients. In Non-SCC patients,
GEM did not impact on survival (p=0.74). Resection rate was higher in SCC
GEM-group than in non-GEM one (74% versus 54%; p=0.034). Complete
pathological response rate at surgery was a survival predictor (pStage 0-mic
vs I-II-III: 36 vs 18.2 months; p=0.01). In SCC GEM-group complete pathological response were higher than in non-GEM one (66% vs 26%; p=0.001).Also
in non resected patients (trials A-D) SCC histology had benefit from radiotherapy and GEM (16.2 vs 10,2 months), even if statistical significance was
not reached (p=0.11). In the last study (trial E) association between Radiochemotherapy and target therapy was tested. In recent year a novel drug
(Pemetrexed- PEM) had demonstrate activity in Non-SCC histology. This was
confirmed also in our series in association with Erlotinib (E-) and Radiation
therapy with a higher median survival and PFS in Non-SCC patients treatedwith E-PEM versus E-GEM (14.4 vs 4.9 months; p=0.01; 7.5 vs 4.6 months;
p=0.06, respectively).

T UESDAY, M AY 10, 2011

T UESDAY, M AY 10, 2011

Symposium
Inter-fraction (between fractions) challenges - organ deformation and motion
280 speaker
IMAGE REGISTRATION AND DOSE WARPING FOR INTERFRACTION DEFORMATION
K. Brock1
1
P RINCESS M ARGARET H OSPITAL, Department of Medical Physics, Toronto,
CanadaConclusions: In the era of "the right drug for the right patients" the choice ofthe concurrent agent to radiation is a particular interesting topic. Even if third
generation drugs in chemo-radiation had confirmed better results comparedwith previous drugs, a more accurate selection of concurrent agents is warranted. In particular our data confirm the role of histology in the selection of
agents also in concurrent radio-chemotherapy treatment. So, stratification oftherapy according to histology should be a key point in ideating future phase
III trials. Integration with target therapies could be considered another innovative aspect in integrated therapies. 1 J Clin Oncol. 2008 Jul 20;26(21):354351.
2 Annals of Oncology 15: 389398, 2004
3 J Thorac Cardiovasc Surg 31:314-21, 2006
4 Lung Cancer 54, 331-338, 2006
5 J Thorac Oncol. 4: 20096
Data not publishedInter-fraction motion and deformation can be a substantial source of geometric and dosimetric error for many tumor sites treated with external beam
radiotherapy. The motion and deformation can be attributed to several factors
including patient positioning (e.g. reproducing the same neck flexion), physiology (e.g. base-line shifts in breathing motion), and treatment response (e.g.
tumor shrinkage). The complexities of these motion and deformations challenge image registration algorithms, yet accurate dose accumulation depends
on their ability to accurately account for these vast changes in position, shape,and size. This presentation will highlight techniques employed in deformableimage registration algorithms to accurately model these complex changes,
including biomechanical model-based and geometric-intensity based algorithms. Mathematical and phantom-based techniques will be described tovalidate the accuracy of these algorithms in this complex setting, including
the results of multi-center studies focused on evaluating the accuracy of deformable registration algorithms. In additional, the dosimetric impact of theseinter-fraction variations in anatomy will be illustrated. Examples will be shown
for anatomical sites including head and neck, liver, and cervix cancer.
281 speaker
DOSE MAPPING ALGORITHMS AND ERRORS
J. Siebers1
1
V IRGINIA C OMMONWEALTH U NIVERSITY, Department of Radiation
Oncology, Richmond, VA, USA
Dose mapping associates the dose delivered to an irradiated deformed geometry to its spatial location in a reference geometry. Mapped doses canthen be summed for dose accumulation and treatment outcomes analysis.
The correspondence between an irradiated and reference image is given by
the deformation vector field produced by a deformable image registration algorithm. Typically, dose in the reference geometry is assigned to the doseat the corresponding voxel location in the irradiated geometry using either
nearest-neighbor or tri-linear interpolation. Although generally accurate, indose gradient regions which overlap tissue heterogeneities dose errors aslarge as 25% have been demonstrated for dose interpolation methods. Two
Monte Carlo dose algorithms, one which transports particles in deformed reference voxels, the other which maps energy depositions from irradiated toreference voxels, avoid this error; however, the Monte Carlo methods are sensitive to mismatches in the masses of corresponding regions in the reference
and irradiated geometries. Similarly, a direct energy mapping method which
can be used with both conventional and Monte Carlo dose algorithms avoids
the dose interpolation error yet is sensitive to mass deviations. Sources oferror in dose mapping include image registration errors, mass deviations between the irradiated and reference geometries, and the use of insufficiently
fine dose matrix resolutions. Several methods exist to detect dose mapping
errors: use of visual analysis to reveal dose ’motion’ in non-moving tissues;
use of back-and-forth dose mapping to find changes in the dose distribution;
checks on the consistency of integral dose in arbitrary sub-volumes in the reference and irradiated geometries; and analysis of dose-mass histograms fortreatment regions of interest. However, there currently are no known methods
for unequivocally determining whether a dose mapping is error free, and thus
represents the true dose mapping. Consequently, dose mapping should be
used with caution, with clinical effects of possible errors considered in a final
analysis.
282 speaker
NON-RIGID DOSE SUMMATION WITH RESPECT TO ORGAN
DEFORMATION BETWEEN FRACTIONS
T. Piotrowski12 , A. Ryczkowski1 , J. Kazmierska32
1
G REATER P OLAND C ANCER C ENTRE, Medical Physics, Poznan, Poland
2
U NIVERSITY OF M EDICAL S CIENCES, Electroradiology, Poznan, Poland
3
G REAT P OLAND C ANCER C ENTRE, 2nd Radiotherapy Department,
Poznan, Poland
Purpose: The aim is to develop and evaluate the method of the calculation ofdose accumulation in normal tissues in the head and neck region, based on
the pre-registered images processed on GPU by algorithms of elastic masking.

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Material and Method: 20 patients with cancer of oral cavity and oropharynx
were selected. Patients were treated to the total dose of 70 Gy on the Tomotherapy unit (HT). Rigid registration was performed for each fraction during the whole treatment course. Contours for parotids and spinal cord were
customized for actual anatomy detected on MVCT scans. Initial data obtained from rigid registration were used in second step of elastic masking.
B-Spline algorithm with customized masking procedure was used. Prioritiesof the masks were automatically calculated based on mismatch detected during rigid registration. Obtained matrix of deformation vectors were used for
fraction dose reorganization and dose accumulation. All computations were
performed using software developed by authors, in Matlab environment with
64-bit architecture computer. Software was optimized for Nvidia GPU computations using Jacket software.
Result: No statistical nor clinical differences were observed in the accuracyof registrations based on images initially registered on the HT and non preregistered (p>0.7). Use of the pre-registered data reduced the total time ofthe elastic registration procedure by 5 % (from 1200 s to 1140 s). Moreover,these data were necessary for intelligent masking during B-Spline registration.
Intelligent masking procedure increased the accuracy of the registration formasked structure (p<0.03) without decreasing the accuracy in non-masked
tissues. Moreover, additional reduction of the total time by 13% was observed(from 1140 s to 990 s).
GPU computations speeded up the procedure fivefold (from 990 s to 200 s).
Initial volume of the parotids decreased by 10-20% during the RT course.
Additionally, inward displacements were observed (average vector equal to3 mm). As a result, the average of the conventionally accumulated dose(recalculated and rigidly summed) was 10 % higher than the planned dose(increasing from 25.5 Gy to 28.4 Gy). However, the elastic masking procedure shows that the accumulated dose was only 7 % higher than the planned
dose (from 25.5 Gy to 27.3 Gy). Vector of the maximum movement of the
spinal cord was 5 mm. Maximum doses, cumulated in 2 % of the spinal cord
volume, were 33 Gy and 34 Gy for the planned dose distribution and elastic
accumulation of doses, respectively.
Conclusions: GPU computing of elastic registrations can be made in a reasonable time after a fraction dose delivery. The correctness of the proposedmodel enables its implementation in the routine assessment and recording of
the anatomic changes occurring in healthy tissue during the course of radiotherapy. Further development should be focused on the optimal schedule ofthe image-based monitoring.

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T UESDAY, M AY 10, 2011

Symposium
Brachytherapy - imaging and dose adaptation.
Joint with GEC-ESTRO
283 speaker
STATUS OF MR, CT AND US IMAGING IN BRACHYTHERAPY
G. Lowe1
1
M OUNT V ERNON H OSPITAL, Physics , Northwood Middlesex, United
Kingdom
Brachytherapy has been practised since the early days of radiation therapy,
and several well-known formalisms for dose delivery have been published
Manchester and Paris being two well-known examples which pre-date theavailability of cross-sectional imaging. These have been used for many years
in a variety of clinical settings, and as a result a large amount of clinical experience in their safe and appropriate application has been gained.
Whereas anatomical cross-sectional imaging has been in routine use formany years now for external beam radiotherapy planning, it is only more recently that the field of brachytherapy has started to make full use of the relevant anatomical and functional imaging data now available. This has led torecent developments and enhancements to treatment options. Considerable
effort has been required to reconcile the newly available imaging data withthe clinical experience gained using traditional brachytherapy formalisms developed without imaging, and some issues remain to be fully addressed.
From a physics point of view, imaging requirements are different from theexternal beam case in that current treatment planning systems (following TG43) do not require electron or physical density data, and therefore there is
no requirement to include CT imaging. One must not forget however the recent introduction of planning algorithms based on Boltzmann-type radiationtransport which would be capable of modeling the dose perturbation due toinhomogeneities in the patient if CT data are available.
Applicator reconstruction is an additional challenge. Although many MRcompatible applicators are now available, some MR scanners produce complex artefacts, for example from titanium cervical tandem and ring applicators,
which must be completely understood before their clinical use as a primaryimaging modality.
Multi-modality imaging is often used the technique of image registration isslightly different from the approach used in external beam in that the applicators themselves sometimes provide fiducial markers which can be accuratelyaligned. However this is not without its complications, particularly because
timing is often critical because image processing takes place whist the postsurgical patient awaits treatment.
In cervix brachytherapy the introduction of CT and MR imaging allows for deviation from the traditional standard plan. This has recently been shown toallow for extension of the high-dose envelope to encompass disease extending into the parametria; in addition, the use of contoured critical structures (asdistinct from the traditional ICRU reference points) allows plan modification tominimize dose to these structures and thereby allow for a degree of dose escalation. It is here that the desire to introduce new techniques and increase
dose must proceed with care not to disregard the clinical experience gained
over the years of treatment using standard plans without imaging. Issues
such as dose to the upper vagina, and dose to "normal" parametrial tissue
bordering on parts of the CTV must be considered, although most clinicalprotocols do not include these as critical structures.
In the field of prostate brachytherapy, ultrasound imaging can be used as thesole modality, once again so long as the limitations and pitfalls are properly
understood. This is an alternative technique to the use of CT, MR, or the twoin combination. There are future possibilities based on the use of functional
MR imaging to delineate the dominant intra-prostatic lesion, for example using spectroscopy, DCE or diffusion-weighted imaging; this may lend itself tothe simultaneous delivery of a boost to a region of the prostate, whilst stilltreating the whole gland using HDR brachytherapy. Validation of this type oftechnique remains a challenge.
Partial breast irradiation using techniques such as Mammosite also benefits
from simple image guidance, as does intraluminal brachytherapy.
The requirements for quality assurance of treatment delivery escalate as thecomplexity of treatment increases, and as larger doses are delivered to diseased tissue close to critical structures. This will extend to clinical as well as
physical aspects (such as contouring). In prostate seed brachytherapy, forexample, significant programs exist already to ensure the planning and delivery of an implant should be reasonably consistent internationally. Cervix
brachytherapy is the subject of current investigations, and the literature describing the comparison of different traditions of treatment is illustrative of theissues faced in modernizing a very long tradition of treatment.
This symposium talk will illustrate some current practices in the use of crosssectional imaging for brachytherapy (CT, MR and ultrasound) and will discusscurrent clinical issues and some future possibilities.

T UESDAY, M AY 10, 2011

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284 speaker

285 speaker

OVERVIEW OF STUDIES ON ORGAN INTERFRACTION VARIATIONS IN BRACHYTHERAPY
T. P. Hellebust121
O SLO U NIVERSITY H OSPITAL, Department of Medical Physics, Oslo,
Norway2
N ORWEGIAN R ADIATION P ROTECTION AUTHORITY (NRPA), Osteras,
NorwayDOSE ADAPTATION BY MODERN TREATMENT PLANNING CONCEPTS INCLUDING INVERSE PLANNING
P. Trnkova1 , C. Kirisits2
1
M EDICAL U NIVERSITY OF V IENNA, Department of Radiotherapy, Vienna,
Austria2
M EDICAL U NIVERSITY V IENNA , AKH, Department of Radiotherapy,
Vienna, Austria

Purpose/Objectives: Implementation of an adaptive approach using 3D
image based treatment planning in brachytherapy has increased in thelast decade. In high dose rate and pulsed dose rate brachytherapy thetreatment is delivered using typically two to six fractions with one or several
applicator insertions. Interfraction variations of the applicator positions inrelation to anatomical structure including dosimetrical consequences havebeen published by several groups. However, the analysis performed and themethods of reporting these interfraction variations are very different making
an intercomparison difficult. This work seeks to give an overview of thedifferent methods published and to try to identify crucial points in reportinginterfraction variations in brachytherapy.
Results: Some authors have published interfraction variations by giving
the displacement of the applicator(s) in relation to bony landmarks using
fluoroscopy or radiographs [1,2,3]. However, the movement of the applicator
in relation to target structures and organs at risk (OAR) are essential andconsequentially soft tissue image modalities, such as CT or MRI, should be
used when interfraction variation in brachytherapy are analysed. Furthermore, an analysis of displacement should be translated into a dosimetricalimpact to quantify the clinical significance of applicator migration.
In external beam radiotherapy the treatment is usually delivered with morethat ten fractions and interfraction variation is often quantified in termsof standard deviations. This approach was adapted by Hellebust et al ingynaecological brachytherapy where they demonstrated that the averagerelative standard deviations for 13 series of 3-6 fractions were 15 and 17.5%
for D2cc for the rectum and bladder, respectively [4]. They did not look into
the total course of treatment on an individual patient level. This approach
was, however, used by Kirisits et al in a study were they compared individual
MRI based 3D treatment planning for each fraction with the use of only one
MRI treatment plan in cervical cancer brachytherapy [5]. They performed afull-course DVH analysis to try to quantify a potential benefit of performing
3D imaging prior to each fraction. This method was also used by Beriwal etal [6]. Simnor et al compared changes in DVH parameters for three fractionsof interstitial prostate brachytherapy with and without a needle movement
correction [7]. In all these three publications the average difference between
single and multiple treatment plan approach is given. The range of thedifferences does, however, show that there are large variations between thepatients. Kirisits et al showed that for D2cc of sigmoid the average difference
was 5.8 Gy (EQD2) with a range of -0.5 to 14.9 Gy (EQD2). With the single
plan approach 5 patients exceeded the dose limits for the sigmoid, while
the dose constraints could be reached for all the patients using a multiple
plan approach. This means the average change from a single plan to a
multiple plan approach is perhaps not the important parameter to measure.
The results should be given on an individual patient level and analysis totry to identify patients that will benefit from a multiple approach should be
performed. Simnor performed such an analysis by plotting the mean catheter
displacement against the difference in DVH-parameters.
Conclusion: The approach of quantifying interfraction variation in terms ofstandard deviation may not be a proper method in brachytherapy since only
a few fractions are used. The method of using limited number of treatment
plans should be compared to the approach of performing treatment planningprior to each fraction. The results should be given on an individual patientlevel and groups of patient that benefit from the latter method should
preferably be identified.

A 3D image guided brachytherapy is a state-of-art in many centers. Integration of imaging methods lead to the treatment plans individually tailored foreach patient. A dose distribution is optimized with the respect to individual
patient anatomy and organs’ topography. The aim of such optimization is todeliver as much dose as possible in the target structures whereas organs at
risk should be spared.
There are several methods of treatment plan optimization. All of them arebased on the adaptation of dwell positions and dwell times. In so called forward approaches the dwell positions and dwell times are first optimized andthen the dose volume parameters are evaluated. It is an iterative process
where the dose and volume parameters guide the adjustment of the dose
distribution.
In case of bigger tumours, a lot of applicators and / or unfavourable organ topography such optimization can be a complex problem with many degrees of
freedom. Forward approaches can be time consuming and often not resulting in the optimal solution. Inverse planning, which was recently introducedin the brachytherapy, integrates the anatomical information of each individual
patient with dosimetrical requirements. Dose volume constraints are definedfor each anatomical volume of interest and the task of inverse planning algorithm is to derive adequate dwell positions and dwell times configuration that
fulfils a set of limits and constraints to the highest possible degree.
There are several inverse optimization algorithms commercially available.
They differ not only in the calculation engines but also in the implementation
into the treatment planning system. In case of brachytherapy the proper implementation of inverse planning is crucial. Although an unexperienced use of
inverse planning can result in similar DVH values the spatial dose distribution
can be very different. This could result in a clinical impact.

1. Hoskin P et al Radiother Oncol 1996;40:59-62.
2. Bahena JH et al Int J Rad Onc Biol Phys 1998;41:13-19.
3. Datta NR et al Radiother Oncol 2001;60:15-24.
4. Hellebust TP et Radiother Oncol 2001;60:273-280.
5. Kirisits C et al Radiother Oncol 2006;81:269-275.
6. Beriwal S et al Clin Oncol 2009;21:483-487.
7. Simnor T et Radiother Oncol 2009;93:253-258.

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Symposium
Functional imaging and image technology
286 speaker
BIOLOGICAL BASIS OF FUNCTIONAL IMAGING
J. Bussink1
1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Radiation Oncology,
Nijmegen, Netherlands
Introduction: Several features that are characterizing the tumor microenvironment explain tumors response to radiotherapy. Besides intrinsic radioresistance, these are tumor cell hypoxia and accelerated tumor cell proliferation.
Hypoxia: To reduce the negative effect of tumor cell hypoxia radiotherapy canbe applied together with hypoxia decreasing procedures such as hyperoxicgas breathing during treatment or stimulation tumor blood flow. The more
recent introduction of IMRT allows specific boosting of tumor subvolumes
that may harbor radioresistant tumor cells. Visualizing these subvolumes bymeans of PET imaging for this purpose has great potential.
A further advantage of PET is the potential to monitor tumor metabolism
during treatment. This allows to prospectively assessing changes in tumor
metabolism, at which time a response on CT is not yet visible. Non-invasive
monitoring of changes in the biologically relevant resistance parameters earlyin the course of treatment may allow modifying therapy thereby preventing patients to be exposed to ineffective treatment and unnecessary side effects.
Histology and Autoradiography: The microregional distribution patterns ofhypoxia affect the distribution of 18F-labeled nitroimidazole derivative autoradiography. Overall significant correlations exist between the PET-tracers andthe hypoxic fraction (pimonidazole). However, several studies experiments
also showed that the pattern of 18F-labeled nitroimidazole derivative accumulation dependents on the underlying micro-regional distribution of tumor
hypoxia. The potential to detect a decrease in hypoxia induced by carbogen
breathing is also strongly tumor model dependent. These observations form
the basis for further validation of the use of PET tracers for hypoxia as a noninvasive functional assay of treatment-induced changes in tumor hypoxia.
Conclusions: Immunohistochemistry and PET-imaging can both be used
to visualize treatment-induced changes in the tumor microenvironment.
Treatment-induced intra-tumoral changes of parameters that are well known
to cause radiation resistance such as tumor cell hypoxia can thus be monitored. However, at this moment microenvironmental changes visualized andquantified by means of PET-imaging need to be validated by high-resolution
microscopic techniques. This will allow interpretation of imaging techniqueswith intermediate resolution (such as PET/CT) in relation to complex cellularsignaling in response to anti-cancer treatments.
287 speaker
IMAGE SEGMENTATION / REGISTRATION IN A MULTI MODALITY
PLATFORM
J. Lee1
1
UCL U NIVERSITÉ CATHOLIQUE DE L OUVAIN, Center for Molecular Imaging
and Experimental Radiotherapy , Brussels, Belgium
The analogy between radiation oncology and a ballistic problem allows one tointuitively understand the importance of imaging in radiation oncology treatment planning. For many years, computed tomography (CT) has been an
indispensable modality for two main reasons: it provides anatomical details
and it measures the tissue electronic densities. Recently, however, othermodalities have raised some interest, such as magnetic resonance (MR) andpositron emission tomography (PET). The latter modality supplies functional
information, which is complementary to the CT anatomical images. The appeal of PET is even reinforced by the wide availability of combined PET/CT
systems. However, the use of additional modalities in treatment planninggenerally proves to be difficult and raises two problems: the accurate segmentation of the images and their registration with the reference CT images.
The issue of registration also occurs in promising treatment planning strategies, such as adaptive radiotherapy, which allows one to assess the actual
dose delivery and to correct for any drifts.
The course will first define what images are and will review some of their basic properties (the resolution, the pixel grid, the statistical nature of the pixel
intensities, etc.). Special emphasis will be put on resolution. Illustrations of
the effect of noise, resolution blur, reconstruction artifacts, and other distortions will be shown.
Next, the task of image segmentation will be defined. The different data structures that can be used to encode the segmentation results will be reviewed(masks, probability maps, contours) and illustrated. A general overview ofthe various segmentation principles will be sketched, allowing one to distinguish several methods, which rely on a global histogram, which exploit theimage spatial structure, or which involve expert knowledge, such as atlasbased segmentation. Some basic segmentation methods such as hard andsoft thresholding will be illustrated. The interest of the gradient operator will
be highlighted; along with a method that involves gradient information, suchas the watershed transform.

T UESDAY, M AY 10, 2011
The third part of the course will be devoted to a general overview of image
registration. Firstly, the problem of image registration will be stated. Next, depending on the application and the expected type of displacement or deformation, several models will be proposed. For instance, a rigid-body registration
can compensate for positioning differences, whereas non-rigid or deformableregistration can track the evolution of the patient anatomy during the courseof treatment, or can even map one patient to another one in an atlas application. The course will briefly introduce some similarity measures that areused in intra- and inter-modality registration, along with the principle of multiresolution registration.
Finally, the course will briefly summarize the components of a multimodality
platform, both from a hardware and software point of view. An application thatinvolves multimodality imaging, segmentation, and registration will be given
as an example before drawing some conclusions.
288 speaker
USE OF PET-CT IN RT PLANNING
A. Osztavics
Abstract not received.

T UESDAY, M AY 10, 2011

Proffered paper
GEC Proffered papers 7: Head and Neck289 oral
LIMITED-VOLUME PERIOPERATIVE HDR BRACHYTHERAPY AS A
SUBSTITUTE FOR WIDE-FIELD EBRT IN RESECTED HEAD & NECKCANCER
M. Gaztañaga1 , I. San Miguel1 , M. E. Rodríguez1 , M. Pagola Divasson1 ,M. Cambeiro1 , M. Moreno-Jimenez1 , J. J. Aristu1 , N. Montesdeoca2 , J.
Alcalde3 , R. Martínez-Monge1
1
C LINICA U NIVERSITARIA DE N AVARRA, Oncology, Pamplona, Spain
2
C LINICA U NIVERSITARIA DE N AVARRA, Maxillofacial Surgery, Pamplona,
Spain
3
C LINICA U NIVERSITARIA DE N AVARRA, Otolaryngology, Pamplona, Spain
Purpose: This study aimed to test the safety of using perioperative highdose rate brachytherapy (PHDRB) to treat limited treatment volumes (TV)in resected head and neck cancer. Data from two institutional prospective,
phase I/II controlled trials for previously irradiated patients (Group 1, Prior
Irradiation, n=40) or high-risk unirradiated patients (Group 2, Unirradiated,n=57) were compared to their respective reference standards: Group 1 vs.
GORTEC-reirradiation trial and Group 2 vs. RTOG 95-01 and EORTC 22931
trials.
Materials: From October 2000 to October 2008, 97 patients (68 men and29 women, median age 59, range 25-85) with squamous cell cancer of thehead and neck received PHDRB after complete macroscopic surgical resection. Group 1 patients received 32 Gy of PHDRB in 8 b.i.d treatments forR0 resections and 40 Gy in 10 b.i.d treatments for R1 resections. No further
external bream radiation therapy (EBRT) or chemotherapy was given. Group
2 patients received 16 Gy of PHDRB in 4 b.i.d treatments for R0 resections
or 24 Gy in 6 b.i.d treatments for R1 resections followed by standard-field
EBRT of 45 Gy in 25 daily fractions of 1.8 Gy with or without concomitantchemotherapy.
Results: The median follow-up for patients alive at the time of this analysis
was 4.3 years (range, 0.5-9.7+). The cumulative hazard of grade ≥3 complications at 2 years in Group 1 patients (Previously Irradiated) , was 45.9%(GORTEC reirradiation trial; 2-year grade ≥3 complication rate = 39.0%);
and the rate of grade ≥3 complications in Group 2 patients (Unirradiated)
was of 24.6% (RTOG 95-01; 5-year rate = 21.0%). In Group 2 patients, thecumulative hazard of grade ≥3 complications was 37.8% (EORTC 22931; 5year cumulative hazard = 38.0%). The rate of locoregional failure for Group 1
patients was 38.1% (GORTEC reirradiation trial = 45.0%), and the rate of locoregional failure for Group 2 patients was 15.8% (RTOG 95-01 = 16.0%). In
Group 2 patients, the cumulative incidence of locoregional failure was 23.1%(EORTC 22931; cumulative incidence = 18.0%). Finally, the 5-year diseasefree survival rate was 32.2% for Group 1 patients (GORTEC reirradiation trial= 22.0%) and 52.4% for Group 2 patients (RTOG 95-01 = 35.0%; EORTC
22931 = 47.0%), respectively.
Conclusions: In this study, the rates of complications, locoregional failure,and disease-free survival were similar to those reported in the reference standards despite a much smaller treatment volume. Careful delineation of theareas at higher risk of recurrence may provide a useful basis for volume reduction and a subsequent improvement in the therapeutic ratio.
290 oral
HIGH DOSE RATE BRACHYTHERAPY IN LIP CARCINOMA
J. L. Guinot1 , L. A. Arribas1 , M. Tortajada-Azcutia1 , M. Carrascosa1 , P.
Soler1 , M. A. Santos1 , M. Chust1
1
I NSTITUTO VALENCIANO O NCOLOGIA, Department of Radiation Oncology,
Valencia, Spain
Purpose: Low dose brachytherapy (BT) is highly effective to treat lip
carcinomas. Nowadays high dose rate (HDR) is the standard in BT but very
few cases have been described. We present our experience with HDR in lip
carcinoma.
Materials: From 1999 to 2007, 80 consecutive patients with invasive lip carcinoma were treated with HDR BT. Mean age was 73 years old (37-101). Therewas 39 T1, 21 T2, 20 T4, and 6 N+. Twelve cases were treated after surgery
with positive margin. Three T4 cases received combined treatment with 50
Gy external beam radiotherapy (EBRT). Parallel metallic needles in a triangle
shape fixed with templates were used. All cases were treated in five days,
most of them with nine fractions of 5 Gy at 90% isodose, twice a day, to a
total dose of 45 Gy. Cervical EBRT was given to 14 patients, 8 cases withpreventive aim.
Results: The median follow-up was 48 months. Five patients suffered local
relapse with actuarial local control of 93.2% at five and ten year (T1:100%,
T2:94.7%, T4:77.3%). Four of them were salvaged with a second treatment.
Seven patients developed nodal metastasis, and four died by tumour progression. Disease free survival was 84.8% at five and ten year. Acute toxicity was
mucositis G3-4 in most patients, completely solved in 6 weeks. Late toxic-

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ity was minimal with good or excellent cosmetic and functional results in allcases.
Conclusions: HDR BT is a simple technique with very good long term results
and very few complications. It can be recommended as a standard in lip
carcinoma and a wider use should be advantageous for selected patients.
291 oral
LONG-TERM RESULTS IN EYELID CARCINOMA TREATED BY
INTERSTITIAL LDR BRACHYTHERAPY. ANALYSIS OF 60 CASES.
L. Masini1 , M. Krengli1 , G. Gambaro1 , E. Negri2 , G. Loi2
1

R ADIOTHERAPY U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ,Novara, Italy
M EDICAL P HYSICS , U NIVERSITY H OSPITAL “M AGGIORE DELLA C ARITÀ ”,
Novara, Italy2

Purpose: Purpose of this study was to evaluate local control, cosmetic andfunctional results over time in patients with cancer of the eyelid treated withinterstitial LDR brachytherapy by 192 Ir wires.
Materials: Sixty patients affected by carcinoma of the eyelid were treated in
our institution between September 1974 and March 2008. Of the 60 patients,
32 were male and 26 female. The mean age was 70 years (range 49-88
years). Fifty one patients (85%) underwent exclusive brachytherapy, 4 patients (7%) postoperative brachytherapy after surgery and 5 patients (8%) at
relapse after surgery. Of the 60 tumours, 51 were (85%) basal cell carcinoma
and 9 (15%) were squamous cell carcinoma. In the 45 previously untreatedpatients, clinical stage was as follows: 30/60 T1N0, 14/40 T2N0, 1/60 T3N0.
Tumour size ranged from 5 to 35 mm with mean of 14 mm and median of
12 mm. Tumour location was lower lid in 37 (62%) patients, upper eyelid in
8 (14%) patients and internal canthus in 15 (25%) patients. Brachytherapy
implant was made by 1 4 192 Ir wires, length 12 50 mm (mean 25 mm), linear
activity between 1.2 and 1.7 mCi/cm. Prescription dose was 51 70 Gy (mean
65 Gy, median 66 Gy) to the isodose of 85%.
Results: Mean follow up was 92 months (range 6-253). Local control was
obtained in 58/60 patients (97%). Functional and cosmetic outcome was satisfactory in 55/60 patients (90%). All patients developed some degree oftransitory acute reaction in the conjunctiva and in the skin adjacent to the interstitial implant. Late effects were evaluated by the RTOG scale: Thirteen patients (22%) had grade 1-2 chronic conjunctivitis, 2 patients (3%) developed
cataract, 3 patients (5%) ectropion and 4 (7%) stenosis of the naso-lacrimal
duct.
Conclusions: Our study shows that interstitial LDR brachytherapy by 192 Ir
wires for carcinoma of the eyelid and inner canthus can obtain satisfactory
results with acceptable late toxicity.
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BRACHYTHERAPY IN LIP CARCINOMA: LONG-TERM RESULTS
M. Guibert1 , M. Rives1 , M. Delannes1
1
I NSTITUT C LAUDIUS R EGAUD, Toulouse, France
Purpose: The aim of this study was to evaluate the effectiveness of low dose
rate brachytherapy for local control and relapse-free survival in squamous andbasal-cell carcinomas of the lips. We compared two groups : one with skinlocalization and the other with mucosal localization of lip carcinoma.
Materials: All patients had been treated at Claudius Regaud cancer centre
from 1990 to 2008 for squamous or basal-cell carcinoma. Low dose ratebrachytherapy was performed with Iridium192 wires according to the "Parissystem" rules. On average, the dose delivered was 65 Gy.
Results: 172 consecutive patients were included in our study. 69 sufferedfrom skin carcinoma (squamous or basal-cell) and 92 suffered from squamous mucosal carcinoma. The average follow-up was 5.4 years. In the skincancer group, there were five local recurrences and one lymph-node recurrence. In the mucosal-cancer group, there were ten local recurrences andfive lymph-node recurrences. The 8-years relapse-free survival for the entire
population was 80%. The 8-years relapse-free survival was 85% for skin carcinoma is 85% and 75% for mucosal carcinoma, with no significant difference
between groups. The functional results were satisfactory for 99% of patientsand the cosmetic results were satisfactory for 92%. Maximal toxicity observed
was grade 2.
Conclusions: Low dose rate brachytherapy can be used to treat lip carcinomas at stages T1 and T2 as the only treatment with excellent results for local
control and relapse-free survival. The benefits of brachytherapy are also cosmetic and functional, with 91% of patients having no side effects.

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EFFICACY AND SAFETY OF HIGH DOSE RATE INTERSTITIAL
BRACHYTHERAPY BOOST IN 88 PATIENTS WITH HEAD NECKCANCERS.
A. Budrukkar1 , N. Khanna1 , R. Bhalavat1 , V. Murthy1 , S. Ghosh-Laskar1 , T.
Gupta1 , R. R. Upreti2 , S. Jamema2 , J. P. Agarwal1
1
TATA M EMORIAL H OSPITAL, Department of Radiation Oncology, Mumbai,
India
2
TATA M EMORIAL H OSPITAL, Department of Medical Physics, Mumbai, India
Purpose: To study the outcome of patients with cancers of Oropharynx andoral cavity treated with external beam radiation therapy (EBRT) and high dose
rate (HDR) interstitial brachytherapy (BRT) boost.
Materials: Between January 1996 to December 2007, 88 patients with oral
and oropharyngeal cancers were treated with radical intent using combinationof EBRT and BRT. All patients after confirmation of histopathology received
EBRT to a median dose 46 Gy/ 23# @ 2 Gy/# daily fractionation schedule.
BRT was accomplished with HDR 192 Iridium to a median dose of 21 Gy (range
10-36 Gy) with dose per fraction of 4.5Gy and a median activity of 6 Curie(range 2-10 Curie). Median number of catheters used in implant was 9 (range3-20). The median gap between EBRT and BRT was 20 days (range 6-99
days).
Results: There were 77 males and 11 females with a median age of 54 years.
Primary site of disease was predominantly oropharynx in 70 (80%) patientsand oral cavity in 18 (20%). The most common subsites were base of tongue
in 25 (28%), tonsil in 21 (24%), oral tongue in 14 (16%) and soft palate in
12 (14%) patients. Majority (N=62, 71%) patients had T2-T3 primary tumor
with median T size of 3cm. Node negative disease was observed clinicallyin 74 patients (84%). Histopathology was squamous carcinoma in all the patients. Type of growth was proliferative in 36 (41%), ulcerative in 46 (52%)
and infiltrative in 6 (7%). Response to EBRT was evaluated under anesthesia
at the time of BRT and showed complete response in 65(74%) and partial
response in 23 (26%).With a median follow up of 43 months (2-168 months)
for surviving patients, 31 patients developed recurrence of which 24 had local
recurrence with 3 and 5 year local control rates of 68% and median time torecurrence being 8.4 months (3-29 months). The 3 and 5 year disease freesurvival was 61% and 60% respectively. The 3 and 5 year overall survival was
70% and 61% respectively. On univariate analysis site of primary (p<0.001),
type of growth (p<0.007) and response to EBRT (p<0.001) were the significant factors affecting disease free survival. Mild xerostomia as evaluated byphysicians was observed in 65 (74%) patients. Mild to moderate soft tissue
fibrosis was seen in 48 (54%) patients. Six patients developed mucosal atrophy and 4 patients had telengectasia. None of them had bone, cartilage orsoft tissue necrosis.
Conclusions: HDR BRT boost in patients with relatively large oropharyngeal
cancers yielded encouraging results for local control and survival with very
low complication and xerostomia rates. However the disease free survival
was significantly inferior in patients with oral cavity tumors. Based on thisdata we have launched a randomized trial of comparing intensity modulated
radiation therapy boost vs BRT boost for oraopharyngeal tumors .
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RUTHENIUM PLAQUE BRACHYTHERAPY FOR UVEAL MELANOMA
D. Smaniotto1 , B. Diletto1 , S. Fersino1 , L. Azario1 , M. G. Sammarco2 , M.
Pagliara2 , M. C. Caputo2 , A. Scupola2 , G. D’ Amico2 , L. Tagliaferri1 , S.
Luzi1 , E. Balestrazzi2 , M. A. Blasi2 , N. Cellini1
1
C ATHOLIC U NIVERSITY OF S ACRED H EART, Department of Bioimaging
and Radiologic Science, Radiotherapy Institute, Rome, Italy
2
C ATHOLIC U NIVERSITY OF S ACRED H EART, Department of Ophthalmology,
Rome, Italy
Purpose: Radiotherapy is still the most widely used treatment for uveal
melanoma, and the most commonly used form of radiotherapy is brachytherapy, using a radioactive plaque. Ru-106 or I-125 plaques have been proven tobe highly efficient in small and medium-sized tumours. A spherically curved
plaque containing radioactive sources is sutured onto the sclera underling thetumor, where it remains for 3 to 10 days. A highly localized and intense doseof irradiation is delivered to the tumor, allowing normal tissue sparing. Often,
brachytherapy is combined with some form of local ophthalmologic treatment,
which is mostly laser coagulation. We evaluated the best treatment with Ru
106 brachyterapy of choroidal and ciliary body melanomas in terms of plaquetype and energy according to localization and size of tumour.
Materials: Between December 2006 and November 2010, 118 patientswith choroidal or ciliary body melanoma were treated by Ruthenium plaquebrachytherapy in the Ocular Oncology Centre of Catholic University of Rome.
Each case was evaluated in a weekly multidisciplinary meeting with ophthalmologists, radiotherapists and clinical physicists, and it was assessed thebest treatment taking into account the following parameters: tumor size, its
localization (choroidal or ciliary body), proximity to macula or ocular nerve.
Treatment planning was performed by physicists and validated by radiotherapists and ophthalmologists. The dose prescribed to the apix of tumor was100%.

T UESDAY, M AY 10, 2011
Results: : The median age of patients was 63 years (range:18-91); 60 tumors
were localized into the right eye, 22 lesions were localized into the ciliary bodyand 96 into the choroid. The diameters of the lesions before treatment were:
medium height 3,7 mm (median: 3,49; range:2,1-8,8), medium trasversal diameter 8,8 mm (median:8,4; range:5,09-15), medium longitudinal diameter
9,3 (median: 9,4; range:4,16-14,9). We used spherically curved plaques of
Ru 106 (BEBIG PLAQUES, in particularly: CCA in 40 cases (34%), COB in
32 cases (27%), CCB in 28 cases (24%) and CCD in 18 cases (15%), withthis active zone diameter of plaques: CCA 13 mm, CCB 18 mm, COB 17 mm(notched for tumors near macula or optical nerve). The mean value of dose
rate was 164.17 cGy/h (median 153.77, range 286.57 - 84.31). No patients
had acute toxicity; 22 patients had a reduction of visual acuity > 3/10 at 1
year. Two patients had retinal detachment and one had haemovitreous.
Conclusions: Brachytherapy with Ru 106 plaques is an easily implementable
technique, able to treat tumors of choroidal and ciliary body, moreover is awell tolerated treatment with a low toxicity profile.

T UESDAY, M AY 10, 2011

GEC Proffered Papers 8: Gynecological Cancer
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IMAGE GUIDED INTERSTITIAL PDR BRACHYTHERAPY FOR LOCALLY ADVANCED PRIMARY OR RECURRENT GYNAECOLOGICALCANCER
L. Fokdal1 , S. K. Nielsen2 , K. Tanderup1 , H. K. Christensen3 , J. C.
Lindegaard1
1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
3
A ARHUS U NIVERSITY H OSPITAL, Department of Surgery, Aarhus N,
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mor characteristics, including histopathology, tumor stage were noted. Detailsof treatment like EBRT and BT were reviewed. Total (external + brachytherapy) EQD2 doses for target were calculated. BT implantation procedure was
performed under spinal anesthesia and X-ray or CT based planning done andconsisted of one insertion and 4-6 fractions treatments depending on the response. A dose of 3.4 - 4 Gy per fraction with 2 fractions per day 6 hours
apart was planned.
Results: A total of 135 patients were treated by MUPIT implant in our hospital. Out of 135, 113 patients were eligible for final analysis. This study population included 37 patients of postoperative (R2 resection) carcinoma cervix,
57 patients with vault recurrence and 19 with carcinoma vagina. The meanfollow up period was 28 months (median 23 months, range 4-99 months).
The table summarizes the outcome analysis. Various prognostic factors, likeage (< or > 40yrs), disease volume (<4cm or >4cm), parametrium involvement, vaginal extension of disease , response to external radiation therapy(CR versus PR) after EBRT were also analyzed.

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BRACHYTHERAPY IN CHILDREN WITH RHABDOMYOSARCOMAS
OF THE NASOLABIAL FOLD: TREATMENT RESULTS OF 16 CASES
R. Mazeron1 , O. Oberlin1 , I. Dumas1 , F. Kolb1 , C. Haie-Meder1
1
I NSTITUT G USTAVE R OUSSY, Villejuif, France
Purpose: Rhabdomyosarcomas (RMS) are rare, accounting for about 2-4%of all malignancies in children and can occur in nearly all parts of the body.
The nasolabial fold is difficult to manage due to cosmetic considerations andfunctional role. Therefore, brachytherapy (BT) has been proposed to improve
local control and limit irradiated volumes or excisions. A retrospective study
was conducted to assess the role of BT in the management of RMS of nasolabial fold.
Materials: The medical reports of 16 patients treated for RMS withbrachytherapy between 1971 and 2005 were identified from the registries of
the BT department and retrospectively reviewed. At the time of diagnosis,
patients age ranged from 5 months to 13.5 years. Ten were younger than
3 years. Half of the patients were male. Histological subtypes included 10
embryonal RMS and 6 alveolar. At diagnosis, the tumour diameter was 20
mm (6-45). For all children the treatment began with chemotherapy (1 to 12
cycles, median: 6), and 11 children received IVA (ifosfamide, vincristine, actinomycin D). In two cases, BT was used as part of a salvage treatment after
chemotherapy. In four cases, BT was the sole local treatment offered. In mostcases, the local treatment was followed by chemotherapy (12/16 cases).
Results: Median follow-up was 4.4 years (1.7-33). Two lesions were classified IIA and the remaining III, according to the IRS. At the time of local
treatment, median tumour diameter was 11 mm (0-26), and 6 children werein complete clinical remission. In 12 cases, BT was used in combination withsurgery. For those children, a complete resection was achieved in 4 cases,
positive microscopic margins for 7, and macroscopic tumour remnant in 1
case. Implantations were performed according to the Paris system rules, andthe treatment delivered by low dose rate (median: 0.48 Gy/h, 0.32-0.66) with192
I wires (median length 3.5 cm) and a median number of sources of 3 (2 to7). Two plans were needed to cover 6 volumes. The doses delivered ranged
from 50 to 70 Gy, depending on the residual tumour volume after chemotherapy and the status of the margins in case of surgery. The median volume of
100% isodose (V100%) was 6 cm3 (2.7-18.1). 6 children never relapsed. Of
them, 5 had embryonal RMS. Out of the 6 patients treated for alveolar RMS,
5 relapsed. Ten patients experienced relapses. 5 local failures (31%) werereported from which 4 were in the irradiated volume. Among the 8 patientswith incomplete resection, 3 local relapses were observed. 6 regional (cervical lymph nodes) and 2 metastatic relapses (bone and muscles) were also
reported. The median time to relapse was 6.5 months and all except one
occurred within 9 months. Only two relapses were salvaged: one local withchemotherapy intensification and surgery, and one regional with chemo and
EBRT. At the time of analysis, 8 patients were alive, 1 dead. 7 were lost tofollow up but were receiving palliative care at their last follow-up or had returned to their native country because of the terminal nature of their disease.
Therefore, overall survival at 5 years was 50%.
Conclusions: In this particular site, BT gives a local control lower than inpelvic sites (vagina or bladder/prostate) but the patients in this series also had
a poor regional prognosis. This data raises the question of a more aggressive
local treatment and the management of cervical lymph nodes.

Purpose: To assess treatment outcome of image and laparoscopic guided
interstitial pulsed dose rate brachytherapy (PDR-BT) for locally advanced primary or recurrent gynaecological cancer.
Materials: Twenty-four consecutive patients (pts) treated in the period 6/2005
to 8/2010 with locally advanced primary (n=9) or recurrent (n=15) gynaecological cancer were included. Median age was 69 years (range 39-83 years).
Treatment was initiated with whole pelvic external beam radiotherapy (EBRT).
Median dose was 45 Gy (range 45-50) in 25 fractions (range 25-32). Within
2 weeks after EBRT, a PDR-BT boost was delivered using the Martinez Universal Perineal Interstitial Template (MUPIT). All implants were virtually preplanned on BrachyVision using T2 weighted MRI of the pelvis with a dummy
MUPIT in situ. The subsequent implantation was performed under direct intraabdominal laparoscopic visualization of the target. The median number of
implanted needles were 13 (range 9-22). Computed Tomography (CT) was
performed 1-2 hours after implantation and fused with the preplanning MRI.
The HR CTV as defined by use of information from clinical examination, MRI,
laparoscopy and CT, was contoured as well as the organs at risk (OAR) in
terms of bladder, rectum and sigmoid. Prescribed dose of PDR-BT to HR
CTV was 30 Gy delivered in 50 hourly pulses of 0.6 Gy. Manual dose optimization was performed with the aim of reaching a D90 > 80 Gy in the HR
CTV avoiding confluence of double dose volume between needles. The minimal dose to the most irradiated 0.1 cm3 and 2.0 cm3 of OAR were evaluated(D0.1cc, D2cc) using dose constraints for D2cc of 90 Gy for bladder and 70
Gy for rectum and sigmoid.
Results: The median volume of HR-CTV was 29 cm3 (range 7-91). Mediancoverage of the HR-CTV was 97% (range 90-100%). The median D90 for HRCTV was 82 Gy (range 77-88). The D2cc to the bladder, the rectum and thesigmoid was 66 Gy (range 47-81), 61 Gy (range 55-77), and 52 Gy (range 4468), respectively. At a median follow-up of 18 month (range 6-47), recurrencein the HR-CTV has been recorded in 2 pts with large volume HR CTV (64and 91 cm3 ) and in 1 pt with a clear cell carcinoma, resulting in an actuarial
2 year local control rate (LC) of 90%. Disease-free survival (DFS) and overall
survival (OS) was 60% and 76% respectively. No acute complication to thelaparoscopic guided implantation was encountered. Late grade 2 (CTC-AE v
3.0) vaginal, gastrointestinal and bladder morbidity was recorded in 4, 2 and0 patient, respectively. Other grade 2 morbidities included lymphoedema (1pt) pelvic insufficiency fracture (3 pt) and pelvic pain (2 pts). No grade 3-4
complications have been recorded so far.
Conclusions: Image and laparoscopic guided interstitial PDR-BT using the
MUPIT for transperineal implantation and a HR CTV concept defined at timeof BT is an effective treatment of locally advanced primary or recurrent gynaecological cancer with low morbidity.
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CLINICAL OUTCOME OF PATIENTS TREATED WITH TEMPLATE
BASED HIGH DOSE RATE (HDR) INTERSTITIAL BRACHYTHERAPYBOOST IN GYNECOLOGICAL MALIGNANCIESU. Mahantshetty1 , S. Banerjee2 , S. Chopra1 , R. Engineer3 , S. K.
Shrivastava3
TATA M EMORIAL H OSPITAL, Department of Medical Physics and Radiation
Safety, Mumbai, India
2
A HARYA H ARIHAR R EGIONAL C ANCER C ENTER, Department of Medical
Physics and Radiation Safety, Cuttack, India
3
TATA M EMORIAL H OSPITAL, Mumbai, India
1

Purpose: Gynaecological cancers (mainly cancer cervix) constitutes approximately 10% of all cancers in India. Most of the cases present at advanced stages or after inadvertent & inadequate surgery. These patients aretreated with radical radiation therapy (external + interstitial) with or without
chemotherapy. With an aim to introspect and report the outcome of patientstreated with HDR Interstitial Brachytherapy Boost with MUPIT at our institution we undertook this retrospective analysis.
Materials: The treatment charts of patients treated with MUPIT between January 1995 and December 2008 were retrospectively reviewed. Patient and tu-

Conclusions: Radical radiation therapy with Interstitial HDR boost showsa reasonable outcome and comparable. The late sequelae although within
acceptable limits requires further follow-up.
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VAGINAL VAULT BRACHYTHERAPY IN ENDOMETRIAL CANCER:
IMPROVING OUTCOMES WITH IMAGE GUIDED APPLICATORPLACEMENTP. Humphrey1 , P. Cornes2 , H. Al-Booz2
1

B RISTOL H AEMATOLOGY & O NCOLOGY C ENTRE, Radiotherapy Dept,
Bristol, United Kingdom
B RISTOL H AEMATOLOGY & O NCOLOGY C ENTRE, Bristol, United Kingdom

2

Purpose: For intermediate risk stage I endometrial cancer, the PORTEC 2
trial has shown vaginal vault brachytherapy is as effective as external beam
pelvic radiotherapy. Vaginal brachytherhapy applicators in current use varyfrom individualised vaginal moulds to standard size cylinders. Standard cylinder applicators have been reported to show a 32-80% chance of air gaps
between applicator and vaginal wall that could reduce the dose below the expected prescription point. This Quality Assurance Study looks to see if thisawareness, coupled with high resolution CT image guided verification has led
to improvements in the technique over time. The clinical target of vaginal lymphatics lies within 3mm in the stretched vaginal mucosa (Choo et al, 2005).
An air gap greater than 2mm will prevent a portion of the lymphatic channels
from receiving the prescribed dose.
Materials: The rate of air gaps seen in the two published observational series
were 98 in 175 insertions (90 gaps/150 insertions (Richardson 2010) and 8
gaps/25 insertions (Cameron 2008). Between Jan to July 2010, 51 consecutive patients had image guided cylinder applicator adjuvant brachytherapy
for endometrial cancer. Spiral CT with voxels of 1mm were taken and analysed on a Brachyvision planning system (Varian Medical Systems). Air gapsof >2mm mandated applicator repositioning; sometimes a larger size cylinder
was inserted. Imaging was repeated until optimum fit was achieved or individualised treatment decisions had to be made. Comparisons were made withresults from this centre of 2008 and the combined literature series.
Results: Initial vaginal cylinder sizes selected by clinical examination were
2.6 cm, 21 %; 3.0 cm, 58% and 3.5, 21%. Air gaps of >2mm were seen inS 118

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7/51 patients. Repositioning reduced this to 4/51. A significant improvement
in applicator positioning is suggested in our centre between 2008 (Cameron2008) and now (Fisher Exact Probability Test 0.01). This suggests a significant improvement over the total data published to 2010 (Pearson Chi squared
test =36.98 (p <.0001).
Conclusions: Individualised vaginal applicators will take more resources todeliver adjuvant vaginal brachytherapy than standard designs. The realisationof standard applicator limitations, coupled with image guided placement andverification can be used to improve the quality of insertions; in our centre reducing from 32% to 8% those needing individualised brachytherapy solutions
or imperfect treatment.
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VAGINAL BRACHYTHERAPY WITH MRI GUIDANCE: TARGET
VOLUME DEFINITION AND EFFECT OF BLADDER FILLING ON
DOSE TO ORGANS AT RISK.
R. Nout1 , I. M. Jürgenliemk-Schulz2 , M. Laman1 , C. Nomden2 , M.
Ketelaars1 , A. de Leeuw2 , C. Creutzberg1
1
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Department of ClinicalOncology, Leiden, Netherlands
2
U NIVERSITY M EDICAL C ENTER U TRECHT, Department of Radiation
Oncology, Utrecht, Netherlands
Purpose: Postoperative vaginal brachytherapy (VBT) has become standard of care for high-intermediate risk endometrial carcinoma patients in the
Netherlands. ICRU guidelines suggest reporting tumor and organs at risk
(OAR) dose points derived from two-dimensional images; little is known about
the 3D dose volume histogram (DVH) parameters for VBT using MRI. The purpose of this study was to quantify the effect of moderate bladder filling on thedose to OAR and to define the clinical target volume with respect to vaginalwall thickness.
Materials: MRI scans in treatment position were obtained for 10 patientstreated with VBT using a MRI compatible vaginal cylinder, both with an empty
bladder and after moderate filling (100 cc). MRI protocol consisted of T2
weighted images in axial, sagittal and coronal directions and a 3D bSSFP
volume scan for reconstruction purposes. On both sets of MRI scans OAR
were contoured (bladder, urethra, rectum, sigmoid and bowel) by four radiation oncologists. Treatment plans were made with 7 Gy prescribed at 5 mmfrom the cylinder surface and from the cylinder apex, with the 100% isodose
covering the proximal half of the vagina. Mean 2cc dose (D2cc) of the OAR,
and dose to the ICRU bladder and rectal points were calculated and compared with the t-test. D2cc estimates were calculated for 21 Gy in 3 fractions
and transformed to EQD2 data using an α/β =3 for OAR. Vaginal wall thickness was measured at the apex and at 2.5 cm and 5 cm distally in the anterior,posterior, and lateral directions, and the maximum wall thickness at any pointin the proximal vagina was recorded.
Results: Analysis was based on the first 5 patients with 1 observer. Bladderfilling resulted in a decreased dose to the bowel (mean decrease of D2cc 4.0
Gy EQD2, range 2.5 - 6.5 Gy) and urethra; and in lesser extent to sigmoid
and rectum. The dose to the bladder increased (mean increase of D2cc 2.3
Gy EQD2, range -3.8 12.5 Gy EQD2). Mean overall vaginal wall thickness
was 2.8 mm. At the cylinder apex the mean cranial wall thickness was 3.3
mm (range 2.5 - 5 mm); anterior wall 2.5 mm (2 - 3 mm); posterior wall 2.2
mm (2 - 3 mm); and lateral 3 mm (2 4 mm). The maximal thickness at any
point in the proximal vagina was 7.4 mm (range 7 8 mm); this point was mostoften located at the apex lateral wall.
Conclusions: Moderate bladder filling impacts on D2cc estimates of OAR.
This can be of clinical relevance when constraints of OAR are reached, i.e.
when VBT is given as a boost after external beam radiotherapy or as retreatment. The vaginal wall thickness averaged 2.8 mm; the dorsal wall was
thinnest (2.2 mm), while the maximal thickness was noted at the apex lateral wall (7.4 mm). Clinical target volume definition based on 3D MRI images
in the proximal part of the vagina is largely unknown. Updated results withinterobserver variations will be presented.
300 oralIN VIVO DOSIMETRY FOR GYNAECOLOGICAL BRACHYTHERAPYBASED ON A NOVEL RADPOS SYSTEM.
B. Reniers1 , G. Landry1 , R. Eichner1 , E. Bloemen- van Gurp1 , L. Murrer1 ,F. Verhaegen1
1
MAASTRO C LINIC, Maastricht, Netherlands
Purpose: High dose rate (HDR) brachytherapy with 192 Ir would benefit fromin vivo dosimetry to ensure correct dose delivery. With dwell position optimisation and the advent of model based dose calculation algorithms accounting
for heterogeneities, treatment complexity has increased and requires quality
assurance procedures. Metal oxide field effect transistors (MOSFET) havebeen proposed as in vivo dosimeters due to their small sensitive volume anddirect readout. Knowledge of dosimeter position with respect to the source ofradiation is paramount to the interpretation of in vivo measurements given the
sharp dose gradients found in HDR brachytherapy. The prototype RADPOST UESDAY, M AY 10, 2011

T UESDAY, M AY 10, 2011

system (Best Medical Canada) consists of a MOSFET dosimeter physicallycoupled to a position-sensing probe, which deduces its 3D position in static
magnetic fields generated by a transmitter. The purpose of this study was toassess the feasibility of 192 Ir in vivo dosimetry with the RADPOS system.
Materials: Using a PMMA phantom, (I) the positioning accuracy of the RADPOS system was assessed by comparing position readouts with the known
position of the detector along the X, Y and Z axes. (II) RADPOS dose measurements were performed at fixed distances from a Nucletron 192 Ir source ina PMMA phantom. The photon energy spectrum at each distance from the Irsource was calculated using Monte Carlo (MC) calculations to determine theenergy response of the MOSFET used in the RADPOS system. With knowledge of (I) and (II) the RADPOS system can be used at arbitrary positions in
the PMMA phantom in order to evaluate the dose.
Results: (I) Positioning accuracy (Fig 1a) was found to be within 1mm in the
110 cm range from the source, meeting the requirements for in vivo dosimetry. Similar results are obtained for positions along the other axes. (II) Fig 1bgives the energy correction factor normalized at 1cm measured at different
distances from the source. The secondary x-axis gives the mean energy at
the corresponding depth. The results agree with literature* showing that thepresence of the position sensor does not influence the energy dependency of
the MOSFET.(I) Positioning accuracy (Fig 1a) was found to be within 0.5 mm
in the 110 cm range from the source, meeting the requirements for in vivo
dosimetry. Similar results are obtained for positions along the other axes. (II)Fig 1b gives the energy correction factor normalized at 1 cm measured at
different distances from the source. The secondary x-axis gives the meanenergy at the corresponding depth. The results agree with literature* showing that the presence of the position sensor does not influence the energy
dependency of the MOSFET.

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CORRELATION BETWEEN IN-VIVO DOSIMETRY AND 3D DOSE
VOLUME PARAMETERS IN PDR BRACHYTHERAPY OF CERVICALCANCER
J. Kallehauge1 , S. K. Nielsen2 , L. U. Fokdal3 , J. C. Lindegaard3 , K.
Tanderup1
D EPARTMENT OF EXPERIMENTAL CLINICAL ONCOLOGY, Århus, Denmark
D EPARTMENT OF M EDICAL P HYSICS, Aarhus, Denmark
3
D EPARTMENT OF C LINICAL O NCOLOGY, Aarhus , Denmark

1

2

Purpose: The introduction of image guided brachytherapy has made it possible to calculate doses to critical normal tissues in 3D. However, the question
remains whether the calculated dose is the same as the actual delivered dose
measured in the patient. This study explores the correlation between rectal invivo dosimetry and calculated rectal dose in pulsed dose rate brachytherapy(PDR BT).
Materials: 38 patients with cervical cancer were analysed. EBRT of 45-50
Gy/25 fractions was administered, followed by MR image guided PDR- BT. A
total dose of 30-35Gy in 2 fractions, 15-20 hourly pulses was delivered withPDR BT, using either an intracavitary tandem-ring applicator (Varian) alone
or in combination with interstitial needles. The target volumes and OARs
were delineated according to GEC ESTRO guidelines. Dose optimisation
was performed aiming at >85 Gy to HR-CTV, <90 Gy to bladder, and <7075 Gy to rectum and sigmoid in terms of equivalent dose in 2 Gy fractions(EQD2). In vivo dose measurement was performed during BT, using a rectal
5 fold diode dosimeter (PTW). The dose measured in the diode receiving
the highest dose was compared to estimated maximal dose in the diodes ascalculated in the treatment planning system (Varian). Furthermore, the ICRU
reference point and D2cc rectal dose were calculated.
Results: Linear regression showed a significant correlation (p<0.001) between measured diode dose and the estimated diode dose, the D2cc (figure), as well as the ICRU reference point dose. Regression coefficients were0.591±0.075, 0.511±0.083, and 0.257±0.073, respectively. The 95% prediction intervals were symmetric around the regression lines i.e. ±2.010 Gy,±2.180 Gy and ±2.661 Gy, respectively.The measured dose for each pulse
decreased slightly relative to the dose of the first pulse dose with -0.16±0.04%/hour (p=0.003) during treatment. The 95% prediction interval was ±17.9%
around the regression line. The clinical action level at our institution is ±15%and data analysed in this study reveals an incidence of measurements exceeding the lower and upper level of 7.99% and 3.32%, respectively.

Conclusions: The results showed a good linear correlation between rectal invivo dose and organ dose as calculated in the TPS (ICRU and D2cc dose). In
vivo diode dose can predict D2cc to a reasonable degree, making substantialchanges in measured dose a good indicator for major unexpected changes
in rectal dose that may have happened either between imaging and deliveryof BT or during PDR BT itself. However, the sensitivity of in vivo dosimetry toless pronounced errors is limited.
Conclusions: Combining accurate 3D positioning data and dose measurements, the RADPOS system shows promise as an in vivo dosimetry system
for HDR brachytherapy. reference *V. O. Zilio et al. Med Phys 33(6), pp 15322013, June 2006

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LONG TERM FOLLOW-UP AFTER CHEMORADIATION AND HIGHDOSE RATE BRACHYTHERAPY AS CONSERVATIVE FOR VULVARCANCER
M. Jolicoeur1 , T. V. Nguyen2 , S. David3 , P. Gauthier4 , P. Sauthier4 , D.
Provencher4 , M. C. Beauchemin2 , P. Drouin4
1
H OPITAL C HARLES L EMOYNE, radiation-oncology, Longueuil, Canada
2
CHUM - C AMPUS N OTRE -DAME, Radiation Oncology, Montréal, Canada
3
CHUM - C AMPUS N OTRE -DAME, Department of Medical Physics andRadiation Safety, Montréal, Canada
4
CHUM - C AMPUS N OTRE -DAME, Gynecology oncology, Montréal, Canada
Purpose: To evaluate the efficacy and safety of high dose rate (HDR)
brachytherapy as a component of a sphincter sparing treatment for advanceor reccurent vulvar carcinoma.
Materials: Patients were eligible for this pilot study if they had a biopsyproven squamous cell or adenocarcinoma of the vulva, an advance primaryS 120S YMPOSIUM

or recurrent disease. The treatment consisted of chemotherapy concomitantwith pelvic radiation of 45Gy/25fr to the vulva and loco-regional areas. A
boost dose was given to the inguinal nodes by electron or conformal therapy. Boost dose to the vulvar area was achieved by interstitial brachytherapy.
Implant was according to the localisation of the primary. Dosimetry was CT
scan based and an Iridium-192 afterloading system was used to deliver aboost dose of 20Gy/10fr/55 hours.
Results: From November 1997 and December 2006, 41 patients medianage 65 years were included in this prospective study. Patients were stage
according to the FIGO system: 13- stage II, 25-stage III, 3- IV and 2 hadrecurrent disease. There were 37 squamous cell carcinomas and 4 adenocarcinomas. Chemotherapy consisted of platinum (n= 16) or mitomicin (n=25)
based regimen. With a median follow-up of 80 months, the local control rateand loco-regional control rate are 85% and 96% respectively. The diseasefree survival, the overall survival and the disease-specific survival are respectively 79%, 90% and 92% at 5 years. Sphincter preservation rate is 100%.
There was no treatment related death. The most common acute toxicities
were: grade 2 genito-urinary (73%), grade 2 gastrointestinal (70.8%), Grade
3 dermatologic (50%) and febrile neutopenia (5%). Late toxicity mostly consisted of skin fibrosis, telangiectasia in 25% and Grade 2 vaginal atrophy, 3patients had soft tissues necrosis treated by hyperbaric oxygen
Conclusions: Interstitial HDR brachytherapy used as a boost to concomitant chemoradiation provides good results as a sphincter sparing approach inselected patients with vulvar cancer.

T UESDAY, M AY 10, 2011

Symposium
ESTRO - CARO Joint Symposium: Translating research in imaging into clinical practice
303 speaker
FROM GENOMICS TO INDIVIDUALIZED TREATMENT
B. Wouters1
1
P RINCESS M ARGARET H OSPITAL, Toronto, Canada
Important advances in a variety of human diseases including cancer havebeen made through the development and implementation of standardized, evidenced based, treatment protocols. However, implicit in such standardization
is an assumption that the nature of the disease amongst different individuals
is similar, and that patients have similar probabilities of benefiting from thetreatment in question. For cancer therapy in general, and radiation therapy
in particular, this assumption holds only to a first approximation, as several
known biological variables that influence treatment response vary significantly
both within and amongst different tumors. For radiotherapy, these include differences in proliferation, hypoxic fraction, and even the intrinsic radiosensitivity of the tumor cells in question. Recent advances in molecular imaging
have provided tools to assess these properties, particularly their spatial variation within tumors, and to aid in delivering individualized treatment. However,the underlying basis for differences in the biological properties amongst tumors lies in the recent observation that at the genetic level, individual tumors
show an extremely high level of heterogeneity. Rapid technological advances
have revealed that individual tumors often contain thousands of mutations
and that the number of different genes that contribute to cancer development
is much higher than previously thought. Consequently, the number of shared
mutations in tumors from individual patients is very small, limited to a few
commonly mutated genes. These observations suggest that deep genomic
characterization of individual tumors is necessary to both understand theirrelevant biological characteristics and to predict the effectiveness of available treatment options. It is likely that genomic characterization of individual
tumors will also provide a better context for interpreting observations madethrough molecular imaging, such that they can be used more effectively for
guiding treatment in the future.

T UESDAY, M AY 10, 2011
elucidate the marker’s efficacy. For full validation, an imaging biomarker mustfor example demonstrate it is accurate, reproducible, and feasible over time,that measured changes over time in the imaging biomarker are closely coupled or linked to the success or failure of the therapeutic effect. In other words
the imaging biomarker must have therapeutic consequences. Only after thatstage, the imaging biomarker can be used for treatment or trial selection, randomization, stratification or as main endpoint.
During the presentation we will focus on two examples:a) a biomarker of hypoxia [18F]HX4
1. Preclinical evaluation and validation of [18F]HX4, a novel promising hypoxia marker for PET imaging. Dubois et al, PNAS submitted
2. PET imaging of hypoxia using [18F]HX4: a phase I trial. van Loon J et al
Eur J Nucl Med Mol Imaging. 2010 Aug;37(9):1663-8.
b) a labeled drug ([89Zr]Cetuximab).
1. Disparity between in vivo EGFR expression and 89Zr-labeled cetuximab
uptake assessed with PET. Aerts HJ et al. P. J Nucl Med. 2009 Jan;50(1):12331.
2. Development and evaluation of a cetuximab-based imaging probe to target
EGFR and EGFRvIII. Aerts HJ et al. Radiother Oncol. 2007 Jun;83(3):32632.

304 speaker
TRANSLATING MOLECULAR IMAGING INTO THE CLINIC: FROM
MOUSE TO MAN
P. Lambin1 , L. Dubois1 , J. Eriksson2 , A. Windhorst2 , D. De Ruysscher1 , G.
Van Dongen2
1
MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS TRICHT, Radiation Oncology, Maastricht, Netherlands
2
VUMC, Nuclear Medicine, Amsterdam, Netherlands
Classically modern translational research tries to bridge two gaps: a) the gap
between in vitro biomedical research and in vivo imaging and b) the gap between preclinical imaging and clinical imaging. In this paper we will focus on
the last one. Clinical translation of scientific discoveries is often the long-termgoal of academic medical research. However, this goal is not always realized
due to the complicated path between bench research and clinical use. In thisabstract, we outline the fundamental steps required for first-in-human testingof a new imaging biomarker with [18F]HX4 and [89Zr]Cetuximab as examples.
In theory the regulation for new imaging biomarkers is the same as for therapeutic drugs: after promising preclinical testing, the imaging biomarker
has to be synthesized according to Good Manufacturing Practice guidelines (GMP) and tested for toxicity. An extensive "Investigator Brochure"
as well as an "Investigational Medicinal Product Dossier" (IMPD) have tobe registered and approved centrally at the national and the European(http://eudract.emea.eu.int) level. After approval, a "first in human trial" hasto be performed. The development follows four discovery and four development steps, being ESD = Exploratory Screen Development, SDS = Screening/Designed Synthesis, LD = Lead Development, CS = Candidate Seeking
for the discovery steps and CAN = Clinical Candidate, phase 0 (pharmacodynamics and -kinetics at very low doses), phase I (toxicity) and phase II(effectiveness) trials as development steps.
Developing and understanding of clinical significance for specific imaging
biomarkers can be a difficult process. There are two main steps of certification for a surrogate endpoint to be fully established:
Qualification and Validation. For an imaging biomarker to become qualified,
it must go through a somewhat formal qualification process. After qualification, an imaging biomarker may have limited use as a surrogate endpoint.
They may be used in phase I and II clinical trials for correlative studies, but
can only be used in phase III trials for early hypothesis generating studies.
There are two steps for validation, probable validation and known validation.
"Probable validation" requires widespread agreement in the medical or scientific community as to its efficacy, which it is linked to the presence of thetarget disease or condition (we speak also of biological validation). "Known
validation" requires a scientific framework or body of evidence that appears to

305 speaker
DOSE PAINTING: HOW AND FOR WHICH TUMOURS?
V. Khoo1
1
R OYAL M ARSDEN H OSPITAL T RUST & I NSTITUTE OF C ANCER R ESEARCH,
London, United Kingdom
In the optimisation of radiotherapy, it is evident that the ability to modulate
our dose provides improved dose distributions. This has developed sequentially from the traditional use of simple wedges to inverse planning for intensity
modulated radiotherapy (IMRT). Clinically IMRT has been used to permit safe
dose escalation in several tumour sites such as prostate cancer with improvements in local control that is hoped will translate into overall survival. IMRT
can also offer a substantial reduction in normal tissue toxicity (eg prostateand head and neck radiotherapy) and improve quality of life indices for thesepatients.
More recently imaging modalities can provide functional and molecular information to better assess tumour heterogeneity and function. Recognised
issues for tumour radioresistance such as hypoxia, enhanced tumour proliferation, and surrogates of tumour activity such as angiogenesis and aminoacid metabolism can now be assessed and evaluated by positron emission
tomography (PET) and functional magnetic resonance imaging (MRI).
IMRT provides the opportunity to create substantial inhomogenous dose distributions with strategies such as simultaneous integrated boosts or zones
of de-escalation of dose. Together with the ability to define subtumour volumes, the concept of dose painting was developed. A further refinement of
this regional subtumour volume dose painting or dose painting by contours isdose painting by numbers or by voxels where dose is allocated according toquantitative imaging parameters of the imaged voxels within the target. Dosepainting can thus provide the most personalised treatment strategy for any
individual and may ideally, in the future, target individual molecular lesions.
Underpinning the strategy of dose painting is the ability to validate that the imaged regions or voxels do represent suitable biological targets that will benefit
from alterations in dose delivered such as increased dose or larger dose fractions. Appropriate histopathological-imaging studies are needed to quantify
the imaging correlates. Careful prospective studies with patterns of failure
evaluation are necessary to quantify the potential benefit of these strategies.
Critical to any sophisticated treatment strategy such as IMRT and particularly
when there are subtarget dose volumes being dose painted is the need for
accuracy and to incorporate image guided radiotherapy methods to ensure

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reliability for dose painting. Future developments should address assessment of tumour response during therapy to enable the opportunity to implement changes in the treatment schema for both favourable and unfavourable
patient scenarios.
306 speaker
REAL TIME IGART WITH LINAC MR HYBRID
G. Fallone1
1
C ROSS C ANCER I NSTITUTE, Department of Medical Physics, Edmonton,
CanadaPurpose/Objective: IGRT attempts to address the uncertainties of the target’s topography during the course of the treatment. Present techniques arelimited by poor soft-tissue visualization and do not allow real-time imaging
during linac/source irradiation. Since MRI provides superior soft-tissue contrast (most cancers are of soft-tissue type), 3 D imaging without gantry rotation and fast imaging, integrating an MRI with a linac/other radiation source
would offer significant advantages for IGRT.
At the Cross Cancer Institute, Edmonton Canada, we designed, studied anddeveloped an integrated linac-MR system consisting of an open bi-planar(split magnet) with a 6 MV linac with two configuration options (Fig). The
MR’s magnetic field runs perpendicularly to the magnet planes and eithertransversely or longitudinally to the linac central axis.. The Lorentz force inthe transverse option does not change dosimetry significantly for homogeneous tissue, but does change it significantly for inhomogeneous tissues (eg,lungs) at magnetic fields greater than 0.2T. These dosimetric changes are
eliminated or considerably reduced in the longitudinal option for higher fields.
In addition, this option provides an increase in dose to the PTV, because themagnetic field confines the electrons to the forward direction, and can thus
potentially reduce dose to the surrounding tissues. The longitudinal option is
only possible in our design.
Results/Discussion: Our first prototype is a 6 MV linac mounted onto theopen end of a biplanar 0.2 T permanent MR system with a 30 cm pole-topole gap in the transverse option. Present MR imaging is operational during
linac irradiation and MR images produced during irradiation were visually andquantitatively similar to those taken with the linac turned off. It provides 4 MR
images/second with tumours that are automatically countoured, tracked, andfollowed by the linac beam through MLC motion. The shape of the contour isalso followed.
We have eliminated mutual interferences between the linac and the MRI systems:
1) RF Issues: The linac 3 GHz RF from the microwave generator does notinterfere with the MRI because it is electro-magnetically contained within theclosed linac system. However, we found that the pulsed power modulator
creates pulses containing low level MHz harmonics which are specific to thelinac and the treatment room. We implemented configurations to reduce RFinterferences resulting in MR images obtained during linac irradiation to be
the same as those obtained when the linac is off. The effects of RF from the
MLC motors were also determined and eliminated.
2) Magnetic Issues: We simulated/optimized/ measured the 3D linac waveguide and Monte-Carlo -simulated the resultant radiation distribution within asubject. We modeled the 3D magnetic fields emanating from the MRI, andoptimized the size and distance of shielding to reduce the field within the
waveguide to avoid significant displacement of the electron trajectory in the
linac. We investigated the magnetic effects on the linac waveguide for boththe transverse and longitudinal options.
In the transverse option, beam loss depends on the field (eg, 45 % at 6 G,
100 % at 14 G), with the production of a highly asymmetric focal spot (13 %profile asymmetry at 6 G). Profile symmetry is regained at the expense of alateral shift in the dose profiles by translating the focal spot with respect to thetarget coordinates. The lateral profile shifts were corrected by adjusting thejaw positions asymmetrically.
In the longitudinal option, only the electron gun optics that is affected. Although, the longitudinal magnetic fields cause large beam losses within theelectron gun, these losses may be eliminated through a redesign of the electron gun optics or through magnetic shielding.
We optimized passive and active magnetic designs to shield the linac against
magnetic interferences, and found that very simple passive and/or active
shielding designs can easily magnetically decouple the linac from the MR
imager.
We also found that commercial MLC system motors can be used if the magnetic fields at their locations are below tolerances, which in extreme cases
can easily be provided with magnetic shielding.
Our system involves the physical coupling of a linac with a rotating biplanar
MR system to prevent image distortion resulting from relative motion between
the magnet and the linac. However, since the magnet rotates with respect tothe patient, there may be a change in tissue magnetic susceptibility as themagnet rotates resulting in image distortion. We have shown that MRIs withfields below 1.5 T can still maintain acceptable geometric accuracy with rotation.
Conclusion: We are presently implementing the longitudinal option integrating a 6 MV linac to a 0.5 MR system with a 60 cm pole-to-pole gap with, atthe very least, the same imaging and auto-tracking-radiation features of ourpresent prototype.

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Proffered paper
Clinical Proffered Papers 4: Breast Cancer
307 oral
RISK OF SECOND MALIGNANCIES (SM) AFTER BREAST CANCER(BC) TREATMENT AND THEIR RELATIONSHIP WITH THE ADJUVANT RADIOTHERAPY: LONG TERM RESULTS
Y. Kirova1 , Y. de Rycke2 , C. Gautier2 , C. François1 , B. Asselain1 , A.
Fourquet1
1
I NSTITUT C URIE, Paris, France
2
I NSTITUT C URIE, Statistics, Paris, France
Purpose: To assess the role of radiation therapy (RT) and others adjuvant
treatments in the development of SM after longer follow-up and continued
monitoring of these patients to confirm the validity and stability of previously
published results.
Materials: A study of a large single institutional registry-based cohort was
conducted on 24,682 women treated for early stage BC at the Institut Curie
between 1981 and 2000. Of them 17,745 were analyzed (excludes male,metastatic and bilateral BC and patients who had already diagnosis of othercancer before BC): 14,512 patients were treated with radiation therapy (RT)and 3,233 without RT. Incidence of various types of second malignancies
were measured, and the age-standardized incidence ratios (SIRs) for eachmalignancy were estimated, using data for the general French population.
Results: At a median follow-up of 13.4 years (range 2-29), 2370 patients
had developed SM as follows: 2010 (13.8%) patients with SM in RT and 360(11.1%) in no RT group. The 13.4 -year risk of any second malignancy was
nearly identical for both cohorts (8.6% v 7.5%, respectively, NS). The 13.4year risk of a second nonbreast malignancy was 5% for the RT and 4% for
the no RT group. In comparison with the general population, the studied
population had a higher risk of SM (SIR: 2.96 [2.81-3.11]). The greatest riskincreases were seen in hematological malignancies (SIR: 2.4 [1.85-3.03]),
gynecological (SIR: 1.31 [1.14-1.49]), and lung cancers (SIR 1.39 [1.12-1.72],
none of them related to RT. The incidences of gastrointestinal and head andneck cancers were lower in the studied population in comparison with thegeneral French population. No increased risk was observed for malignant
melanoma, genito-urinary, and thyroid cancers.
Conclusions: With a median follow up of 13.4 years, women treated forbreast cancer had a significantly increased risk of several kinds of SM, compared to the general population. The magnitude of this absolute risk was
small in the various types of malignancies studied.
308 oral
SECOND PRIMARY CANCER AMONG DANISH WOMEN WITHEARLY BREAST CANCER TREATED WITH POSTOPERATIVERADIOTHERAPY
T. Grantzau1 , M. S. Thomsen2 , L. Mellemkjær3 , J. Overgaard1
1
A ARHUS U NIVERSITY H OSPITAL, Department of Experimental ClinicalOncology, Aarhus C, Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
3
DANISH C ANCER S OCIETY, Institute of Cancer Epidemiology, Copenhagen,Denmark
Purpose: To evaluate long-term second primary cancer risk among women
treated for early breast cancer with postoperative radiotherapy.
Materials: We conducted a cancer-registry based cohort study that included
all Danish women without a prior malignancy who had been treated for earlybreast cancer in the period from 1982 to 2008. The data used in this study
was supplied by The Danish Breast Cancer Cooperative Group (DBCG). In
order to identify the primary second malignancies the DBCG registry was
linked to The Danish Cancer Registry. The Danish Cancer Registry is nationwide and population based. Second primary breast cancer was not considered an outcome in this study. If women were diagnosed with two or moresecond primary cancers only the first cancer was included in order to avoid
the additional effect of any treatment given.
Results: The cohort included 46,176 one-year survivors: 23,627 (51%)
women had received postoperative radiotherapy (RT) and 22,549 (49%) were
non-irradiated. By the end of 2008 with a median follow-up of 6 years (range
1-26) 2,595 second primary cancers had occurred, including 1,148 second
cancers located in or close to the treatment field. Second primary cancers
located in or close to the treatment field were classified as potentially radiotherapy induced. We included among other the following sites: Pharynx,
Larynx, Lung, Pleura, Esophagus, Stomach, Thyroid gland, Pancreas, Colon,
Bone and Connective tissue. The Standardized incidence ratio (SIR) for the
potentially RT induced sites was 1.2 (95% CI 1.1-1.3) among the irradiatedwomen and 1.0 (95% 0.9-1.1) among the non-irradiated women. The risk ofgetting a second primary cancer increased over time since treatment. SIR
for potentially RT induced sites at a latency of +15 years after breast cancer
diagnosis was 1.9 (95%CI 1.4-2.4) among the irradiated women vs. 1.1 (95%
CI 0.9-1.3) among the non-irradiated. Further, the risk of getting a potentially

T UESDAY, M AY 10, 2011
RT induced second cancer increased with decreasing age at treatment. For
the age group 20-49 years of age SIR for the potentially RT induced sites was
1.7 (1.4-2.1) among the irradiated women compared to 1.1 (0.9-1.4) among
the non-irradiated women.
Conclusions: Among the irradiated women there was an increased risk ofgetting several second primary cancers located in or close to the treatment
field and the risk increased over time since treatment.
309 oral
USING PATHOLOGY AND OUTCOME DATA TO ANALYZE THE
DEPENDENCE OF AGE ON RADIOTHERAPY RESPONSE IN
BREAST-CONSERVING THERAPY
W. Chen1 , J. Stroom1 , A. Schmitz2 , H. Bartelink1 , J. J. Sonke1 , K. Gilhuijs2
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiotherapy, Amsterdam, Netherlands
2
U NIVERSITY M EDICAL C ENTER U TRECHT, Radiology, Utrecht, Netherlands
Purpose: Younger (age≤50) and older patients benefited differently fromradiotherapy following breast-conserving surgery (BCS) in multiple clinical trials. However, radiobiological details to explain this difference are still lacking.
The purpose of this study was to estimate the in-vivo radiosensitivity of residual subclinical tumor after BCS in younger and older patients.
Materials: To estimate the radiosensitivity, pathology data and outcome datafrom two studies were retrospectively analyzed: the MARGINS study andthe EORTC 22881-10882 trial ("boost-vs-no-boost"). In the MARGINS study(N=60), wide-local excision specimens were completely embedded and analyzed to establish the volume of subclinical tumor at various distances beyond the edge of index tumor (DEIT). The density of subclinical tumor cells
was established semi-automatically from digitized microscopy images using
the Aperio cell-counting algorithm. In the EORTC trial (N=1616), pathology
was reviewed to establish the association between the width of the negative
surgical margin and the risk of local recurrence. We correlated these datausing Webb’s TCP model, which describes a relation between tumor-cell
kill, the delivered dose, the volume of the irradiated tissue, tumor cell density and radiosensitivity. We separated the results into two groups using an
age-threshold (50 years), and considered the heterogeneous radiotherapyresponse of each group to be normally-distributed. The radiosensitivity inyounger and older patients was subsequently estimated using a Bayesianinference method with Monte-Carlo simulation.
Results: We observed a weak association between the width of negative
surgical margin and the risk of local recurrence in the EORTC trial (Pearson Correlation coefficient, r=-0.007, p=0.8). The volume of subclinical tumor
around invasive cancer (DEIT < 4mm) was 2.5 times larger in younger patients than in older patients in the MARGINS study (p=0.033). The tumor
cell density was approximately 4.90E+05 cells/mm3 in younger patients, and4.34E+05 cells/mm3 in older patients (p=0.28). After correction of these factors, we still observed a significant difference (p<0.001) in radiosensitivity between younger and older patients: 0.49 Gy-1 ±0.17 Gy-1 (1SD) and 0.62 Gy-1
± 0.18 Gy-1 , respectively (see Fig 1).

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310 oral
CURRENT STATUS OF ELIOT STUDIES ON BREAST CANCER AT
THE EUROPEAN INSTITUTE OF ONCOLOGY IN MILAN
R. Orecchia1
1
U NIVERSITY OF M ILAN AND E UROPEAN I NSTITUTE OF O NCOLOGY,
Department of Radio-oncology, Milan, Italy
Purpose: In spite of positive data on the role of post-operative WBI after
breast-conserving surgery, several institutions are trying to revisit the adjuvant irradiation setting, especially with regard to overall treatment time andtarget volume. This concept has been developed by applying the modern
philosophy of partial breast irradiation (PBI). PBI can be realised using external beam RT, brachytherapy or intraoperative RT (IORT). This last approachhas been estensively tested in Milan. ELIOT (Electron IntraOperative Therapy) consists of a single-fraction treatment targeted at the tumour bed, during
the surgical procedure, immediately after the removal of the tumour mass.
The logistic problem to bring the radiation source and the patient together issolved by the use of mobile accelerators that are brought to the operating
room, and produce electron beams with variable energies from 3 up to 12
MeV. Between 1999 and 2000 a pilot phase I-II trial has been conducted on
101 patients in order to identify the maximum tolerated dose. Dose has been
escalated from 10-15 Gy (as anticipated boost) up to 21 Gy, as sole treatment. From 2000 to 2007 the EIO randomizing 1306 patients, in a prospective phase III trial, to receive conventional EBRT (50 Gy to the whole breast
plus a 10 Gy boost to the tumour bed) or a single dose of 21 Gy of ELIOT.
All patients received quadrantectomy followed by SNB and only in cases of
positive nodes, axillary dissection. The primary endpoint for analysis was therate of local recurrence within a 5year observation period. At the same time,patients who either not completely fulfilled the eligibility criteria or refused toenter the randomized trial, were treated with the same modality. From 1999
to 2008, 1822 patients with unicentric primary carcinomas less than 2.5 cm indiameter were treated. After 5-years, 2.3% of the patients developed a true
local recurrence and 1.3% a second lesion in the other quadrant of the samebreast. The 5-years overall survival was 97.5%. Very few developed serious breast fibrosis. Cosmetic results were good/excellent. At the EIO, breast
surgeons and radiation oncologists combined the subcutaneous mastectomy
with ELIOT to the preserved nipple areola complex (NAC). The aim of this approach would be to maintain the blood supply and the sensitivity of the NAC
avoiding the feeling of mutilation carried by mastectomy, while reducing therisk of recurrence in the central area of the breast. A total dose of 16 Gy at
a 90% isodose is delivered in a single fraction to the clinical target volume
that includes the remaining glandular tissue behind the NAC. Breast reconstruction is performed immediately after irradiation. From this experience weconclude that for large or multicentric tumors and/or diffuse microcalcifications far from the NAC, NSM with ELIOT of the NAC obtain good local control
and satisfactory cosmetic results.
Materials:
Results:
Conclusions:
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TARGETED INTRAOPERATIVE RADIOTHERAPY – THE TARGIT-A
TRIAL UPDATE
F. Wenz1 , J. Vaidya1 , D. Joseph1 , M. Bulsara1 , N. Williams1 , J. Tobias1 , M.
Baum1
1
ON BEHALF OF THE TARGIT TRIALISTS ’ GROUP

Conclusions: Radiotherapy response in breast conserving-therapy is agedependent. To our knowledge, this is the first study to estimate in-vivo radiosensitivity by correlating pathology data with outcome data. For the future,
incorporating radiosensitivity into radiotherapy planning may be useful to optimize the radiation dose, thus improving the balance between local tumor
control and cosmetic outcome in breast-conserving therapy.

Purpose: In June 2010, we reported the results of a randomized trial that
tested the safety and efficacy of using TARGeted Intraoperative radiotherapy
in patients older than 45 with operable, small invasive ductal carcinoma of thebreast.It is important to emphasise the pragmatic nature of this trial, which
compared the policy of conventional whole breast radiotherapy (WBRT) with
the new policy of individualized risk-adjusted radiotherapy i.e., intraoperative
partial breast irradiation with the TARGIT technique using the Intrabeam device in 80-85% of cases with addition of postoperative WBRT in 15-20% of patients who are found to have risk factors on final histopathology. The test wasfor non-inferiority with an acceptable margin of 2.5% in absolute terms. We
reported that the Kaplan Meier estimate of local recurrence at 4 years was notstatistically different in the two treatment policies.We have since had further
9 months of follow up (Feb 2011) and the total number of recurrences in theindex breast has increased from 13 to 21. We performed a blinded analysis
and calculated the Kaplan-Meier estimate of local recurrence for the wholecohort and compared it with a similar estimate in May 2010. The KaplanMeier estimate of local recurrence has remained stable but now has narrower
confidence intervals: Feb 2011: 1.09% (95% CI 0.65 1.85) compared with
May 2010: 1.08% (95% CI 0.33 -1.96) at 4 years and Feb 2011: 1.97% (95%
CI 1.20 - 3.21) compared with May 2010: 1.85% (95% CI 0.93 - 3.69) at
5 years.Furthermore, radiation-related quality of life data was collected using
two validated questionnaires (EORTC QLQ-C30, QLQ-BR23) in patients fromone center (Mannheim). The response rate was 72% (n = 88). Compared to
WBRT patients, IORT patients reported significantly less pain, breast andarm symptoms and better role functioning (mean 21±33 vs 41±32, 7±14 vs

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19±20, 15±22 vs 33±29, and 79±35 vs 62±28 points).This update analysis demonstrates that the local recurrence rate has remained stable and the
5-year K-M estimates have not changed significantly with longer follow up.
Furthermore, better quality of life was observed after IORT as compared to
WBRT.
Materials:
Results:
Conclusions:
312 oral
RESULTS OF AN ISIORT POOLED ANALYSIS WITH LINAC-BASEDIORT WITH ELECTRONS (IOERT) AS BOOST STRATEGY DURING
BREAST CONSERVING THERAPY IN LIMITED STAGE BREASTCANCER
F. Sedlmayer1 , G. Fastner1 , F. Merz1 , H. Deutschmann1 , R. Reitsamer2 , C.
Menzel2 , C. Stierle2 , A. Ciabattoni3 , A. Petrucci3 , E. Hager4 , N. Willich5 , C.
Lemanski6 , R. Orecchia7 , V. Valentini81
U NIVERSITY C LINIC S ALZBURG, Department of Radiotherapy andRadio-Oncology, Salzburg, Austria
2
U NIVERSITY C LINIC S ALZBURG, Department of Special Gynecology,
Salzburg, Austria
3
S AN F ILIPPO N ERI H OSPITAL, Department of Radiotherapy, Rome, Italy
4
L ANDESKRANKENHAUS K LAGENFURT, Department of Radiotherapy,
Klagenfurt, Austria
5
U NIVERSITÄTSKLINIKUM M ÜNSTER, Department of Radiotherapy, Münster,Germany
6
G UI DE C HAULIAC M ONTPELLIER T EACHING H OSPITALS, Department ofRadiotherapy, Montpellier, France
7
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Radiotherapy, Milan,
Italy
8
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Department of Radiotherapy, Roma, Italy
Purpose: Linac-based IORT with electrons (IOERT) was implemented to prevent local recurrences after breast conserving therapy (BCT) and was delivered as a single intraoperative boost dose to tumor bed prior to whole breast
radiotherapy (WBRT). A collaborative analysis has been performed by member institutions of the European Group of the ISIORT for long term outcome
evaluation of this strategy.
Materials: 1110 patients have been identified until 10/05 among seven institutions using parallel methods, sequencing and dosage for intra-and postoperative radiotherapy. Fifty-two percent of the patients (586 pat.) presented
with at least one adverse prognostic factor such as larger tumor size, highgrading, young age and/or positive nodes. were directly applied to the tumor
bed. A median single fractional dose of 10 Gy (range 6-17, SD 0,9) was applied to the tumor bed (90% reference isodose), mainly by electron energiesof 4, 6 and 8 MeV (range 4 to 18), using round perspex tubes with 5-8cm diameter. Whole-breast irradiation with 50-54Gy was performed after a mediantime span of 48 days (range 16-357, SD 47,6 ).96,6% of the patients received
additional adjuvant systemic therapy.
Results: As of March 09, only 16 in-breast recurrences were observed in
1110 patients with a median follow up period of 73,3 months yielding a local
tumor control rate of 99,2%. No follow up data were available for 3 patients.
954 patients are alive without evident breast disease at 7 years follow up.
111 patients developed metastases (50 are still alive).108 patients have died,
57 of them from cancer and 13 from a secondary tumor. Recurrences occurred 20-151 months after primary treatment. At 7 years 87,8 % of patients
maintain disease free survival, 93,3 % disease specific survival and 89,7 %overall survival. In univariate analysis, age, grading, hormonal receptor status
and hormonal therapy turned out to be significantly predictive for the development of in-breast recurrence, in multivariate analysis only grade 3 reachedsignificance (p=0,024). Nodal status and dimension of time delay between
IOERT and WBRT showed no influence.In analysis along patient age, annual
in-breast recurrence rates amounted 0,64 %, 0,34 %, 0,21 % and 0,16 % inpatients < 40 a; 40-49 a; 50-59 a and ≥ 60a, respectively.
Conclusions: In all risk subgroups, IOERT as anticipating boost strategy
prior to WBRT achieves outstanding local tumor control rates in long term
observation, comparing favourably to all trials with similar lenght of follow up.

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follow the 3D prescription accurately, due to a limited resolution of the dosedelivery technique.The uniform (Clinic), classical (PTV15) and probabilistic(CTV15L) plans had 90% confidence to have less than 3.5Gy underdose (5%of 70Gy) in the CTV, indicating identical PTV conformity.Considering the local prescription dose, the PTV15 plan had only 70% probability to meet therequirement of less than 3.5Gy underdose. For the CTV15L plan this was
P=83%. Another probabilistic plan (CTV15H) plan with increased weight on
the minimum dose objective recovered a 90% confidence. However, this planincreased the maximum dose in the CTV and surrounding structures.

Physics Proffered Papers 7: IMRT planning andoptimisation
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EFFECTS OF SETUP CORRECTIONS ON THE DOSE DISTRIBUTION OF SBRT OF LUNG CANCER: DOSE INVARIANCE INVALID
BUT THE PTV CONCEPT HOLDS
A. Holt1 , C. van Vliet-Vroegindeweij1 , J. J. Sonke1 , E. M. F. Damen1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
Purpose: The location of lung tumors with respect to the bony anatomy is
known to vary up to cm’s from day to day. To correct for these baseline shifts,
image-guided online correction strategies are commonly applied with SBRTof lung cancer. The underlying PTV concept implicitly assumes dose invariance, which is questionable in inhomogeneous tissues. Therefore, we systematically investigated the effects of corrections for baseline shifts on thedose distributions by recalculating the dose of treatment plans for many possible shifts. The modeled tumor mass was also shifted to closely represent
actual tissue densities.
Materials: The same CT data set was used to investigate different typical tumor types: 1) small ventral, 2) small central and 3) large central. A sphericaltumor mass was modeled using density overrides in a healthy lung. The GTV
was expanded to the PTV using a typical isotropic margin of 7 mm. Noncoplanar IMRT plans were prepared in Pinnacle3 , and a dose of 54 Gy wasprescribed to the isodose encompassing 95% of the PTV volume. Then, dose
distributions were recalculated for a large number of baseline shifts, i.e. shiftsof the tumor mass, using a systematic shift pattern (panel F). Corrections forthese baseline shifts were simulated using isocenter (and hence PTV) shifts.
In addition, the robustness of the PTV concept was tested by additionally shifting the tumor mass within the PTV systematically by 6 mm for each shifted
isocenter to simulate worst case intra-fraction variation after correction. To
test dose invariance, the dose in the PTV was evaluated. Furthermore, thedose in the GTV was evaluated.
Results: The simulated corrections for baseline shifts result in a decreased
lowest PTV coverage V54 with increasing shift distances (panel A), the mostfor the ventral tumor. Only small effects were seen for the central location, regardless of tumor size. The percentage of plans with still satisfying coverage
is below 60%, regardless of tumor location and size (panel B). However, thelowest D99 in the GTV among all calculated scenarios was >53 Gy (panel C).
For the small ventral and large central tumor all calculated scenarios have a
D99 >54 Gy in the GTV, and for the small central tumor only very few scenarios fail this criterion (panel D). The GTV volume receiving at least the prescribed dose of 54 Gy was always larger than 98.8% (panel E). This meansthat even in extreme situations with large isocenter shift and large residual error, i.e. the GTV located close to the border of the PTV, the GTV was covered
with the prescribed dose in almost all calculated scenarios.

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Conclusions: Setup corrections for baseline shifts (and residual errors
therein) where shown to result in significantly lower PTV coverage, showing that dose invariance does not hold in this situation. However, the lowest
D99 of the GTV observed among all calculated correction scenarios was >53
Gy. Our findings confirm the "dose tracks density" paradigm, which rescues
the PTV concept with SBRT of lung cancer.
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PROBABILISTIC DOSE PAINTING BY NUMBERS: COMPARINGACTUAL WITH PRESCRIBED DOSE USING THE VH
M. Witte1 , J. Van de Kamer1 , A. Houweling1 , C. Rasch1 , M. van Herk1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands
Purpose: Dose painting promises dose escalation in those regions were it
counts, without increasing side effects. We implemented a method for probabilistic dose painting by numbers (directly including positioning errors) bydefining a 3D map of the prescribed dose. Such a map can e.g. be based on
FDG-PET. When assessing the quality of resulting dose distributions, conventional DVHs offer limited information. Therefore, we introduce the new ∆VH
concept as evaluation tool for non-uniform dose prescriptions.
Materials: Objectives were re-implemented in the 8.1y research version of
the Pinnacle treatment planning software. Random geometric errors were
simulated by dose blurring, systematic errors by displacing structures relative
to the blurred dose.We selected an oropharynx case with a clinical plan using
6 beam step&shoot IMRT, and 70Gy prescription. A 3D prescribed dose map
was computed as a linear function of he FDG-PET SUV, prescribing 15Gy
extra to the maximum SUV, while keeping the minimum prescription at 70Gy.
IMRT plans were optimized using a minimum dose objective, i.e. each ROI
point needs to have at least the prescription dose. A classical plan was optimized for the PTV, while for probabilistic plans the objective was applied to
the CTV aiming at 90% confidence.DVHs were generated by binning the dosein the PTV, and ∆VHs by subtracting the prescribed dose from the planned
dose in each point before binning. Confidence levels of DVH and ∆VH points
for the CTV were estimated by Monte Carlo sampling of the geometric error
distributions (SD=23mm).
Results: Figure 1 compares DVHs and ∆VHs. For the clinical plan, thecurves are just shifted by 70Gy. Since in a DVH spatial information is lost,
it is not possible to estimate how well the non-uniform plans match the 3D
prescription (curve DSUV). In the ∆VH curves, dose differences are computed per 3D point. The low steepness of the curves in the bottom panel(compared to the clinical plan) shows that the dose could not be sculpted toConclusions: Probabilistic planning techniques are highly suitable for nonuniform dose prescriptions. DVHs are unsuitable, however, to evaluate theresulting dose distributions. We therefore introduced the ∆VH which is suitable for both homogeneous and inhomogeneous dose prescriptions.
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BEAM ANGLE OPTIMIZATION USING DERIVATIVE-FREE ALGORITHMS
H. Rocha1 , J. Matos Dias12 , B. Costa Ferreira34 , M. D. C. Lopes4
1
INESC-C OIMBRA, Coimbra, Portugal
2FE - U NIVERSIDADE DE C OIMBRA, Coimbra, Portugal
3
I3N- U NIVERSIDADE DE AVEIRO, Aveiro, Portugal
4
I NSTITUTO P ORTUGUÊS DE O NCOLOGIA C OIMBRA - F RANCISCO G ENTIL ,EPE, Coimbra, Portugal
Purpose: The selection of appropriate beam directions is decisive for thequality of the treatment, both for maximizing tumor doses and for organs sparing. However, the beam angle optimization (BAO) problem is still an open
problem and, most of the times, beam directions continue to be manually selected in clinical practice with no guarantee of optimality and consumption oflarge amounts of time. Currently, some commercial treatment planning systems are designed to use gradient-based algorithms in the beam angle space
to address the BAO problem. Due to the many local minima aspect of BAO
problem, such approaches are not efficient. We propose a novel beam angle
optimization approach based on derivative-free algorithms.
Materials: Pattern search methods (PSM) framework is a class of derivativefree algorithms making them a suitable approach for the resolution of theS 126

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non-convex BAO problem. PSM are organized around two phases at every iteration: one where convergence to a local minimum is assured (poll), and theother (search) where flexibility is conferred to the method allowing searches
away from the neighborhood of the current iterate. Any global search strategy
can be applied in the search step including the insertion of previously used
and tested strategies. Due to the myopia of pattern search methods, causedby the non-use of derivatives, these methods have the ability to avoid being
trapped by the closest local minima and to find a local minimum in a lowest region. Locally advanced head and neck clinical cases were selected forthis study. The planning target volumes included the primary tumor, the highand low risk lymph nodes. Organs-at-risk (OARs) included both parotids, thebrainstem, and the spinal cord. For each case, a collection of seven equidistant beams were planned using CERR (computational environment for radiotherapy research). The resulting treatment plan was then compared with theplan using the optimal beam set obtained by PSM.
Results: The plan using the optimal beam set obtained by PSM lead to better quality plans for IMRT delivery. The objective function value of the fluence
optimization problem was reduced 15% when using the optimal beam set obtained by PSM instead of the traditional equidistant beam set. OARs sparing
was improved for the plan using the optimal beam set obtained by PSM. For
the same target volume coverage, the mean dose in the right and left parotid
was reduced by 4.62Gy and 2.81Gy, respectively.
Conclusions: PSM have shown the ability to avoid the local minima closest
to the initial angle configuration with a fast convergence. The efficiency on thenumber of function value computation is of the utmost importance in a busy
clinical practice, particularly when adding beam direction to the optimization
problem. Our results have shown that a global beam angle search using
derivative-free optimization methods yields superior quality plans.
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A STUDY OF ICRU 83 GUIDELINES FOR DOSE REPORTING OF
H&N IMRT PATIENTS.
M. Clarke1 , R. Dearden1 , C. Rowbottom1 , S. Smith1
1
T HE C HRISTIE NHS F OUNDATION T RUST, North Western Medical Physics,
Manchester, United Kingdom
Purpose: ICRU Report 83 introduces new recommendations for dose reporting of IMRT treatments. This work aims to compare the practice at this centre
with the new recommendations, examining the consistency and reliability ofeach method for H&N patients.
Materials: Twenty previously treated H&N IMRT patients, planned using the
Pinnacle TPS, were randomly selected, and represented a range of treatmentsites. All patients had a simulated integrated boost treatment, with standard
UK fractionation1 . OARs were outlined, with Spinal Cord and Brainstem expanded by 0.5 cm axially to create PRVs.The original treatment parameters
remained unchanged, with further analysis of the dose statistics conducted.
The departmental conventions for reporting doses were compared to thoserecommended by ICRU 83. This included investigating mean and mediandoses to PTVs, maximum and minimum doses to both absolute volumes, e.g.
1cc, and percentage volumes, e.g. 2%. The maximum doses to PRVs werestudied along with sensitivity to the length of PRV delineated using multiple
protocols.
Results: Comparison of mean and median (D50%) doses for PTV1 showed
the median to be consistently higher with statistical significance, but only byan average of 0.2 Gy. This was deemed insignificant clinically.ICRU 83 recommends reporting the near-maximum and near-minimum absorbed doses,
D2% and D98%, for PTVs. The average 2% volume for PTV1 was 7.98 cc(range 3.06 - 15.73 cc) and for PTV2 was 5.11 cc (range 2.06 - 10.53 cc).
These are relatively large volumes to consider as hot/cold spots. The variance in volume across the cohort of patients creates inconsistency in thereporting of near-maximum and near-minimum absorbed doses for a population. The average dose difference between D2% and D1cc was 0.75 ± 0.16
Gy for PTV1 and 2.03 ± 0.86 Gy for PTV2. The average difference between
D98% and DVol-1cc was 2.47 ± 0.76 Gy for PTV1 and 1.64 ± 0.84 Gy for
PTV2.ICRU 83 recommends recording D2% for PRVs. This volume is often
smaller than 1cc for the Brainstem PRV, and interrogating the dose with sufficient sampling frequency for such small volumes would require unrealistic
dose grid resolution of around 0.15 cm. D2% was found to be highly sensitive
to changes in PRV delineation protocols, necessitating a universal protocol
for scanning and delineating PRVs for it to provide a meaningful measure
for comparison.Reporting D1cc instead of D2%, for example, would allow
a more consistent comparison across departments with different delineation
protocols.
Conclusions: Dose reporting as outlined in ICRU 83 using percentage volumes leads to inconsistencies within a patient cohort and also between departments. The use of an absolute value of volume, e.g. 1cc, provides greater
consistency for reporting of IMRT treatments.1. Clark C H, Hansen V N et al.
(2009). "Dosimetry audit for a multi-centre IMRT head and neck trial." Radiotherapy and Oncology 93(1): 102-108

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DOSIMETRIC COMPARISON OF IMRT USING HELICAL PHOTONBEAMS VERSUS RANGE-MODULATED ELECTRON BEAMS IN
RADIOTHERAPY OF BREAST AND CHEST WALL CANCER
E. Gargioni1 , F. Cremers1 , T. Gauer1 , K. Engel2 , Y. Goy1 , C. Petersen1
1

U NIVERSITY M EDICAL C ENTER H AMBURG - E PPENDORF (UKE), Department for Radiotherapy and Radio-Oncology, Hamburg, Germany
R OSTOCK U NIVERSITY, Institute for Mathematics, Rostock, Germany

2

Purpose: In radiotherapy of breast and chest wall cancer, conventional photon treatment planning often results in high doses to heart and ipsilateral lung.
On the other side, IMRT planning has the advantage of significantly better
sparing surrounding healthy tissue. However, high dose conformity is often
achieved at the cost of considerable low-dose exposures to heart and contralateral breast which might induce secondary malignancies. When using
electrons, IMRT planning opens new possibilities to reach dose conformanceo near-surface targets through both intensity and electron/range modulation.
This study aims at comparing treatment plans obtained by IMRT optimization
with photons versus electrons.
Materials: Treatment plans for five patients (left/right-sided breast, chestwall including lymph nodes, sarcoma of medial chest wall/sternum) were
calculated for both helical photon (TomoTherapy Hi-Art 2.2.2.05) and electron IMRT treatment. For electron IMRT, an accelerator-controlled add-on
electron MLC (Euromechanics) was modelled using a Monte-Carlo beammodelling algorithm (Pinnacle, Release 8.1s). Optimal electron beam parameters (gantry/table angles, intensity, range and MLC shape) were determined by means of a stand-alone optimization program. Electron IMRT plans
were afterwards verified by a film-based dose verification procedure using
GafChromic EBT films (ISP) and a solid-water phantom with breast extension and bone/lung inserts.
Results: The electron IMRT plans were composed of 10-15 beam orientations, 5 energies between 6 and 14 MeV, and 30 to 50 step-and-shoot
MLC segments. Compared to the TomoTherapy approach, IMRT planningwith electrons resulted in considerably better sparing of total healthy tissue.
Electron IMRT for breast cancer also achieved better sparing of heart andcontralateral breast with respect to mean dose, maximum dose, and percentage volume. Mean ipsilateral lung doses were similar with both techniques.
The maximum ipsilateral lung dose could significantly be reduced in all cases
when using electron IMRT. Target coverage by the 95%-isodose, however,
was higher with photon IMRT.
Conclusions: IMRT planning with electrons allows for depth-conformal dose
distributions sparing underlying healthy organs. The resulting IMRT plans
were associated with a low-dose exposure only to small parts of the ipsilateral lung. Compared to corresponding photon plans, the risk of developing
radiation-induced secondary malignancies is therefore much lower when using electrons. Additionally, photon IMRT requires breathing control or gating
techniques due to breast motion during respiration which lead to higher complexity and prolongation of the treatment. Electron dose delivery is generally less affected by breast motion as electron ranges of vertically incoming
electron beams are almost independent of slight source-to-surface distancevariation.
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FULLY INTEGRATED COMPUTERIZED OPTIMIZATION OF BEAM
ANGLES AND FLUENCES IN (NON)-COPLANAR IMRT AND IMPLICATIONS FOR VMATP. Voet1 , S. Breedveld1 , M. Dirkx1 , B. Heijmen1
1
E RASMUS M EDICAL C ENTER R OTTERDAM, Radiation Oncology andMedical Physics, Rotterdam, Netherlands
Purpose: To quantify potential plan improvements of integrated computerized optimization of (non)-coplanar beam directions and intensity profiles for
IMRT treatments of head and neck cancer patients. For VMAT the impact of
optimized non-zero couch angles was assessed.
Materials: An in house developed algorithm for multi-criterial, integrated
beam angle and intensity optimization, named iCycle, [1] was used. For 20
randomly selected head and neck cancer patients to be treated with maximum sparing of salivary glands, 5 plans were designed: i,ii: 7 and 9 beamequi-angular coplanar plans (iCycle7equi, iCycle9equi). iii: a 9 beam coplanar plan with optimized beam angles (iCyclecopl). iv: a 9 beam non-coplanar
plan with optimized gantry- and couch angles (iCyclenoncopl). v: a 9 beam
coplanar plan with an optimized couch angle (iCyclecouch). All iCycle plans
were generated fully automatically using an identical wish-list [2] consisting ofhard constraints and prioritized objectives. To assess differences in plan quality NTCP values for salivary glands were derived. Using Monaco (Elekta AB),
VMAT plans with optimized couch angles derived by iCycle were comparedwith plans without couch rotation.
Results: For each patient, all iCycle plans had similar target coverage. The
best salivary gland sparing was observed for the optimized non-coplanarplans (iCyclenoncopl), yielding a mean NTCP for the parotid glands of 7%(range = 1-47%), and for the submandibular glands of 30% (range=10-65%).
In the table statistics on differences in NTCP values are presented for the

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other plans. Especially for the 7 beam equi-angular plans (iCycle7equi) the
NTCP values were substantially higher (5% on average for the submandibular glands, with a maximum of 20%). 9 equi-angular coplanar beams (iCycle9equi) performed better than 7. By using optimized beam angles (iCyclecopl) sparing of the salivary glands was further improved. For 18 of the
20 patients coplanar plans with one optimized couch angles (iCyclecouch),requiring less delivery time at the treatment unit, were similar to the fully noncoplanar plans. For all patients, compared to VMAT plans without couch rotation, application of the optimized couch angle derived by iCycle improved the
NTCP by up to 4 % for parotid glands and 3 % for submandibular glands.
Conclusions: Integrated computerized optimization of beam profiles and angles for IMRT treatment of head and neck cancer patients can significantly
improve sparing of salivary glands for specific patients. Sparing is optimal
for fully non-coplanar plans. VMAT with an optimized couch angle can improve salivary gland sparing compared to the commonly applied zero couch
angle.1: Breedveld et al, 2009 Radiother. Oncol.: 92, S2042: Breedveld etal, 2009 Phys. Med. Biol.: 54, p7199

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PERIPHERAL DOSES IN PROSTATE CANCER RADIOTHERAPY: A
COMPARISON BETWEEN IMRT AND RAPIDARC TREATMENTS
G. Defraene1 , F. Van den Heuvel1
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Radiation Oncology, Leuven,
Belgium
Purpose: To measure both photon and neutron extraneous doses in different
treatment techniques for prostate cancer radiotherapy and to make a comparison with treatment planning system (TPS) results.
Materials: Optimized 10MV intensity modulated radiotherapy (IMRT) and
RapidArc®(RA) prostate plans to 74 Gy were generated for a standard Alderson phantom. Peripheral dose was measured for one delivered fraction of 2
Gy, using TLD-100 (LiF) for photons (25 positions within the phantom) and2 types of bubble detectors (BDT and BD-PND from BT bubble technology
industries) for (epi)thermal (threshold at 100 keV) and fast neutrons, respectively (5 positions). Measurement uncertainties were on the order of 15% to
25% for neutron doses (detector response, bubble counting, temperature dependence) and lower than 15% for photons.The results were compared with
Varian eclipse TPS and with the Peridose software (Van der Giessen et al.).
Results: In RA lower photon doses per Gy were obtained in all but one position (ranging from 7.4 mGy/Gy in colon to 0.3 mGy/Gy in esophagus). The
main reason was the 16% lower number of monitor units (MU) needed in the
RA plan. Table 1 shows the results (in mGy for a whole treatment of 37 fractions) going from positions close to the field isocenter (colon at 9 cm) towards
larger distances (esophagus at 56 cm). The difference between both techniques varied from 7% to 16% for the mean organ doses. This difference
being not everywhere as low as the 16% MU decrease could be explainedby the slightly larger field size in the RA plan. For the neutron doses nosuch systematic difference was observed (Table 1). The thermal component
was almost constant throughout the body (approximately 0.5 mSv per treatment), whereas the fast neutron component gradually decreased from colon
to esophagus. The contribution of neutrons to the total organ doses was verylow (ranging from 1.2% to 6.3%). The TPS only calculated doses in the colon(underestimations of 30% to 70%). Further away (>20 cm) from the target weonly could use the predictions of the peridose system. Large overestimationsof 60% to 130% were observed here, probably due to a wrong assumption
on the collimator scatter and the high dependence of the peripheral dose
calculation on field size which is not well defined in IMRT.
Conclusions: The photon low dose bath seen in IMRT treatments was diminished with approximately 10% for most peripheral organs with RA. The dosefrom neutrons was representing less than 6% of the total dose in these 10 MV
treatments. Eclipse and peridose failed to robustly predict peripheral doses.
The previously used IMRT with 18 MV beams is also being analysed. Preliminary results showed the photon dose bath to be much higher (up to 1.1
Gy in colon and exceeding 0.5 Gy in lungs), while the neutron contribution
seemed to become more important. Acknowledgements: This study waspartly funded by the ALLEGRO-project (7th Euratom Framework Programme
for Nuclear Research and Training).

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Results: When normalized to the amount of contrast agent injected, AIFPHASE has good agreement in both shape and height with AIFCT. Furthermore, Ktrans maps in corresponding slices of CT and MRI show similar patterns in all patients (subfigure a). Quantitative analysis gives median Ktransvalues for the healthy considered PZ of 0.10 and 0.08 min-1 for the DCE-MRI
and the DCE-CT exam respectively and 0.40 and 0.35 min-1 for ROIsusp(subfigure b). No significant differences (paired Wilcoxon signed rank test)
were found between the Ktrans values of MRI and CT in the PZ (p=0.424) andROIsusp (p=0.380).

Physics Proffered Papers 8: Functional Imaging
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GEOMETRICAL ROBUSTNESS OF DIFFUSION WEIGHTED MRIMAGING OF THE PROSTATE
S. Hoevenaars1 , U. van der Heide1 , T. Schakel1 , M. van Vulpen1 , M.
Philippens1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands
Purpose: Diffusion weighted MR imaging (DW-MRI) has shown to enable
the detection of tumor tissue in the prostate. Its weakness is the occurrenceof geometrical distortions due to small magnetic field inhomogeneities. In
this study we quantified geometrical distortions before and after retrospective
correction of an optimized DW-MRI protocol.
Materials: Pelvic areas of four healthy volunteers and 10 prostate cancer patients were imaged on a 3.0 Tesla MR imaging system (Achieva TX, Philips
Medical Systems, Best, the Netherlands), using a 16 element SENSE HR
Cardiac coil. A diffusion weighted single shot spin-echo echo-planar imaging (ssSE-EPI) sequence was optimized to acquire 20 transverse slices withvoxel sizes 2.00x2.00x4.00 mm3 . The phase encoding direction, in whichmost artifacts occur, was chosen to be lateral to minimize the disturbanceof the prostate geometry by magnetic inhomogeneities induced by rectal air
filling. To maximize the lateral bandwidth and thus to minimize lateral distortions, parallel imaging (SENSE=4) was applied. With this MR sequence,
two images were acquired with geometrical distortions in opposing directions(LR and RL) to quantify the distortions and the effectiveness of retrospective correction. Also a B0 field map of every subject was acquired, reflecting
magnetic field inhomogeneities from which individual pixel shift maps were
derived. These pixel shift maps were used to retrospectively correct for geometrical distortions in the DW-MRIs with the FMRIB FUGUE software[1] . In
house developed software in Matlab was used to estimate the geometrical
distortions before correction of the pixel shift maps. In addition, the initial
shifts and the remaining displacements of the prostate borders after correction were assessed in thresholded absolute subtraction maps of the opposing
DW-MRIs (figures 1a and 1b).
Results: The pixel shift maps derived from the B0 field maps showed a mean
displacement of 2.0 mm in the prostate, with a mean 95th percentile of 3.7
mm. From the subtracted opposing DW-MRIs (figure 1a) a mean shift of 2.5
mm (mean 95th percentile: 4.3 mm) of the prostate borders was obtained.
Retrospective corrections of the distorted DW-MRIs (figure 1b) in the pelvis
reduced the mean geometrical distortion obtained from the subtracted opposing DW-MRIs to 1.9 mm, with a mean 95th percentile of 3.2 mm.

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Materials: Forty-nine patients with biopsy-proven prostate cancer were
prospectively enrolled in an imaging study consisting of T2w-MRI, DCE-MRI
and DW-MRI at 1.5T. All patients underwent radical prostatectomy and extended lymphadenectomy. Histopathological evaluation was performed by anexperienced uropathologist, who delineated cancerous regions on the wholemount haematoxylin and eosin (H&E)-stained sections. MR images were
evaluated independently by 2 experienced uroradiologists who were blinded
for the histopathological findings. Tumor regions were outlined on the different MR modalities in different imaging sessions. Tumor localization wasrecorded and correlated between the pathologic and MR imaging findings.
Therefore, the prostate was divided into 3 regions (base, mid and apex) andevery region was divided further into octants, yielding 24 evaluable segments
per patient. Moreover, analyses were conducted with a stringent approachand a more clinically relevant approach, in which small tumor lesions (< 5mm
were excluded from the analysis.
Results: In total, 1179 segments were analyzed in these 49 patients, ofwhich 654 (55.6%) and 469 (39.9%) contained tumor using the stringent or
clinical approach respectively. According to the stringent analysis the sensitivity and specificity values for T2w-MRI, DCE-MRI and DW-MRI for the first
reader were respectively 25.4% and 94.4%, 21.3% and 93.5%, and 39.3%
and 92.5%. For the clinical analysis the sensitivity and specificity values were33.5% and 94.6%, 26.0% and 92.8%, and 48.8% and 90.5% respectively.
The combination of all 3 MRI modalities resulted in a sensitivity of 52.0%
and 62.9% for the stringent and clinical analysis respectively, while specificity
values were 84.1% and 81.9%. A significant correlation was found between
the total tumour volume (cc) on the histopathological slices and the DW-MRI
slices (Spearman; R=0.64, p<0.0001). The statistical analysis for the data of
the second reader is currently being processed. These results as well as theinter-observer variability and correlation data with relevant clinical parameters
will be presented by the time of congress.
Conclusions: Combining different MRI modalities for prostate cancer detection and localization is feasible with reasonable sensitivity and high specificity.
Multi-modality MR imaging thus represents a valuable approach to guide focalradiation therapy.
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SEGMENTATION OF DCEMR IMAGES OF CERVICAL CANCERS
USING K-MEANS CLUSTERING FOR OUTCOME PREDICTION
E. K. F. Andersen1 , G. B. Kristensen2 , H. Lyng3 , E. Malinen1
1
O SLO U NIVERSITY H OSPITAL, Department of Medical Physics, Oslo,
Norway2
O SLO U NIVERSITY H OSPITAL, Department of Gynaecologic Oncology ,Oslo, Norway
3
O SLO U NIVERSITY H OSPITAL, Department of Radiation Biology, Oslo,
NorwayConclusions: The proposed optimized DW-MRI protocol at 3.0 Tesla resulted in a geometrical distortion in the prostate borders of 2.5 mm, which
can be reduced to 1.9 mm by retrospective correction.References: [1] M.
Jenkinson 2010
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IMPROVING THE ROBUSTNESS OF QUANTITATIVE DYNAMIC
CONTRAST-ENHANCED MRI FOR TUMOR DELINEATION IN
PROSTATE CANCER
J. Korporaal1 , N. van den Berg1 , M. van Osch2 , G. Groenendaal1 , M. van
Vulpen1 , U. van der Heide1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands
2
L EIDEN U NIVERSITY M EDICAL C ENTER, Radiology, Leiden, Netherlands
Purpose: For dose painting in prostate cancer, dynamic contrast-enhanced(DCE) MRI is used to delineate the tumor. However, much uncertainty exists
on what thresholds of the permeability parameters should be used to distinguish tumor from healthy tissue, as parameter values differ substantiallybetween institutes. Contrary to DCE-CT, the conversion from signal to theconcentration contrast agent, needed for quantification with a tracer kinetic
model, can be challenging for DCE-MRI, in particular for the arterial input
function (AIF). The robustness of this quantification can be improved by determining the AIF from the phase of the MRI signal, rather than from its amplitude. The aim of this study is to validate this approach in 12 patients bycomparing it with DCE-CT exams.
Materials: Twelve patients with biopsy proven prostate cancer (mean age
67.5) underwent a DCE-MRI and a DCE-CT exam prior to radiotherapy. DCEMRI was performed on a 3T MRI scanner (TR/TE 4.0/1.7ms) and a total of
120 scans were obtained at a 2.4s time interval, after injection of 0.1 ml/kg
gadobutrol. The DCE-CT exam (120kV, 200mAs) consisted of acquisitions at
42 time points within 5 minutes, after injection of 60ml iopromide.An AIF measured from the MRI amplitude signal has a non-linear relationship with thecontrast agent concentration and suffers from T2*-effects at higher concentrations, B1-field inhomogeneities and inflow-artifacts. Therefore, we measured
the AIF from the phase signal (AIFPHASE), which has a linear relationshipbetween phase shift and contrast agent concentration and is insensitive tothe artifacts mentioned before.Parameter maps of the Tofts model were calculated from the DCE-MRI and DCE-CT exams of each patient. On the Ktransmaps, corresponding regions of interest (ROI) were delineated in healthy considered regions in the peripheral zone (PZ) of the prostate and in regions withelevated Ktrans values, suspected of tumor tissue (ROIsusp).

Conclusions: By using an arterial input function obtained from the MRI
phase signal, quantification of DCE-MRI data with a tracer kinetic model gives
consistent Ktrans values when compared to DCE-CT. This creates the possibility to establish DCE-MRI guidelines for tumor delineation, dose painting andtreatment monitoring for radiation therapy in prostate cancer.
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MULTI-MODALITY MR IMAGING FOR PROSTATE CANCER DETECTION IN CORRELATION TO WHOLE-MOUNT HISTOPATHOLOGY
S. Isebaert1 , L. Van den Bergh1 , K. Haustermans1 , E. Lerut2 , L. De Wever3 ,T. Budiharto1 , P. Slagmolen1 , S. Joniau4 , H. Van Poppel4 , F. Claus3 , R.
Oyen3
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Radiation
Oncology, Leuven, Belgium
2
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Histopathology,
Leuven, Belgium
3
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Radiology, Leuven,
Belgium
4
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Urology, Leuven,
Belgium
Purpose: Accurate imaging is an indispensible prerequisite for focal radiation therapy of prostate cancer. Therefore, the aim of this study was todetermine the value of multi-modality magnetic resonance imaging (MRI) for
accurate detection and localization of intraprostatic tumor nodules by using
T2-weighted (T2w) MRI, dynamic contrast-enhanced MRI (DCE-MRI) anddiffusion-weighted MRI (DW-MRI) with whole-mount histopathology as a gold
standard reference.

Purpose: Dynamic contrast enhanced MRI (DCEMRI) allows for non-invasive
characterization of vascular properties of tumors. The aim of this study was
to determine if regions within tumors showing similar vascularization could be
identified and if these regions was associated with local relapse after radiotherapy.
Materials: Eighty-one patients with locally advanced cervical cancer treatedwith chemoradiotherapy underwent DCEMRI with Gd-DTPA prior to externalbeam radiotherapy. The median follow up time was four years. Nine patients
had local relapse, that is, relapse within the treated volume. Two pharmacokinetic parameters, Ktrans and υ e, were estimated voxel by voxel from the
DCEMR-images. Ktrans characterizes the transfer rate of contrast agent between blood plasma and extravascular-extracellular space (EES), while υ eis the volume fraction of EES to the voxel. Intratumoral regions with similar
vascular properties where classified by k-means clustering of the two pharmacokinetic parameter estimates over all patients. The k-means clustering
method uses an iterative approach to minimize the intracluster scatter, hence
the method may identify clusters of voxels with similar vascular properties.
The volume fraction of each cluster to the tumor volume was used as a metricfor characterizing each tumor. The cluster volume fractions were compared
to treatment outcome by log-rank survival tests.
Results: Classification of voxels using three clusters provided a sufficient reduction of the intercluster point scatter to characterize different vascular properties. The three cluster centers correspond to Ktrans values of 0.10, 0.20 and
0.15 and υ e values of 0.20, 0.45 and 0.80, respectively. The corresponding
median volume fraction of each cluster volume to the tumor volume was 0.43,
0.41 and 0.08, respectively. The second cluster was significantly associatedwith local relapse in a log-rank test (p-value: 0.04), showing a decreased riskof local relapse for patients with high volume fraction of voxels.
Conclusions: Intratumoral regions showing similar vascular properties could
successfully be classified in three distinct clusters and the relative size of one
cluster region was significantly associated with local relapse.

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DOSE PAINTING BY CONTOURS VERSUS DOSE PAINTING BYNUMBERS FOR LOCALLY ADVANCED LUNG TUMOURS; PRACTICAL IMPLICATIONS OF USING A BROAD OR SHARP BRUSH
G. Meijer1 , M. Bal2 , K. De Jaeger1 , D. Schuring1 , J. Steenhuijsen1 , J.
Theuws1
1
C ATHARINA Z IEKENHUIS, Radiotherapy, Eindhoven, Netherlands
2
P HILIPS H EALTHCARE, PO Box 80068, Netherlands
Purpose: Local recurrence remains high in patients with stage II and III
NSCLC with current standard radiation schemes of 66 Gy in 2 Gy fractions.
Boosting high SUV volumes on the pretreatment FDG-PET scan potentially
increases the local control while maintaining acceptable toxicity levels. The
quantitative use of FDG PET data for locally painting the boost dose to lungtumours is currently subject of investigation in multiple studies. In this work
we compare a threshold based dose painting by contours (DPBC) approachversus a voxel based dose painting by numbers (DPBN) approach.
Materials: PET-CT data of 10 stage II and III NSCLC patients were used inthis study. Two dose painted plans were generated for each patient both witha baseline dose of 66 Gy to the entire PTV and boost dose to the high SUV
areas within the primary GTV. The DPBC strategy aims for a uniform boostat the volume encompassing the SUV50% region plus an 8-mm margin. The
DPBN strategy aims for a boost dose that increases linearly with the underlying SUV within the primary GTV (Fig. A). The boost dose was escalated
to 130 Gy or until a dose limiting constraint of an organ at risk was met. In
order to make a fair and unbiased comparison between both strategies, reoptimizations were carried out with tuned (i.e. most confining) dose volume
parameter values of all risk organs whenever needed.

T UESDAY, M AY 10, 2011
Conclusions: Both large brush DPBC and sharp brush DPBN techniques
can be used to considerably boost the dose to the FDG avid regions within
the lung tumour. However, significantly higher boost levels can be obtained in
the high SUV voxels using sharp brush DPBN techniques at the cost of lower
tolerances for tumour setup inaccuracies.
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AUTOMATIC TUMOUR CONTOURING USING FUZZY C-MEANS
CLUSTERING AND SUV THRESHOLDS IN PET/CT FOR
ESOPHAGEAL CANCER PATIENTS
R. Kierkels1 , C. Muijs1 , R. Wierts2 , J. Beukema1 , H. Langendijk1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Department of Radiation Oncology, Groningen, Netherlands
2
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Department of Nuclear Medicine and Molecular Imaging, Groningen,
Netherlands
Purpose: The integration of positron emission tomography-computed tomography (PET-CT) in radiotherapy treatment planning for esophageal cancer
might lead to increased accuracy of gross target volume (GTV) contouring
compared to CT alone. Currently, endoscopic ultrasound (EUS) is used
as ’golden standard’ for tumour length determination in esophageal cancer.
However, it is difficult to translate this information to CT images. Automatic
PET contouring techniques could assist the radiation oncologist during GTV
delineation. The aim of this study was to determine the best automatic PETCT-based delineation method for esophageal tumours and to compare it withcurrently used CT-based delineations.
Materials: Nineteen patients, diagnosed with esophageal cancer, were included in this prospective study. All patients underwent both 18 F-FDG PETCT scan and EUS for tumour length measurement. The FDG-PET scan
(5 MBq/kg) was performed on a Biograph mCT 4-64 PET-CT scanner using the UltraHD (TrueX + ToF) reconstruction algorithm. All PET data werenormalized for the blood glucose level acquired shortly before the injectionof FDG.GTV delineation using PET was performed by means of three different absolute standardized uptake value thresholds (SUV2.0, SUV2.5 andSUV3.0) and Fuzzy C-Means (FCM) clustering (3 and 4 clusters). The GTV
contouring on the CT scan was performed using all available diagnostic information, including EUS. Tumour lengths were recorded from PET- (LPET)and
CT-based (LCT) contours and compared with the EUS measured lengths(LEUS). The concordance indices (CI) and volume ratios were determined
between the PET- and CT-based contours. Mean (±SD) values were compared using the paired t-test.
Results: Using the FCM technique, PET-based GTVs could be obtained forall patients. However, for the absolute SUV threshold technique, we could
not determine a PET-based GTV due to the fact that the SUVmax was below the chosen threshold level. There were no significant differences between all LPET (54±15 mm) and LEUS (52±20 mm) measures. However, the CT-based tumour lengths (LCT = 64±18 mm) differed significantly
from the LEUS (p < 0.01). Volume ratios ranged from 0.47 0.88 indicating smaller PET-based GTVs than CT-based GTV delineations. Mean CI
were 0.44±0.11 for FCM3, 0.38±0.12 for FCM4, 0.52±0.14 for SUV2.0,
0.48±0.16 for SUV2.5, and 0.43±0.17 for SUV3.0. A threshold of SUV2.0
yielded the highest CI between PET/CT- and CT-based GTVs.
Conclusions: PET-based tumour lengths corresponded significantly to EUS
measures, for all PET-based delineation methods. This was not the case forCT-based length measures. A threshold of SUV2.0 yielded the highest CI
and volume ratios. Therefore, the SUV2.0 seems most useful to assist in
GTV delineation for esophageal cancer.
326 oralResults: For two patients (with relatively small peripheral tumours) the dose
within the GTV could be boosted to 130 Gy using both strategies. For the remaining patients the boost dose was confined by a dose limiting constraint ofa critical structure (large vessels 2 lungs 2 bronchus 2 spinal cord 1 brachial
plexus 1. In general the amount of large brush DPBC boosting is limited
whenever the PTVboost is close to any serial risk organ. In contrast DPBN
inherently boosts at a voxel-by-voxel basis allowing significant higher dosevalues (10-40 Gy) to high SUV voxels more distant to the organs at risk. Furthermore, for all patients the biological SUV gradients are reasonably congruent with the dose gradients that can be delivered with a standard linear
accelerator (Fig B). As a word of caution it should be noted that the DPBN
method is inherently marginless meaning that accurate online IGRT setup
procedures are essential to assure correct delivery.

DOSE RESPONSE OF NORMAL LUNG DURING RT ASSESSEDBY CONE BEAM CT - A POTENTIAL TOOL FOR BIOLOGICALLYADAPTIVE RADIATION THERAPY
A. Bertelsen1 2 , T. Schytte1 3 , S. Bentzen4 , O. Hansen1 3 , M. Nielsen2 , C.
Brink1 2
1U NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark
2
O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
Denmark
3
O DENSE U NIVERSITY H OSPITAL, Department of Oncology, Odense,
Denmark
4
U NIVERSITY OF W ISCONSIN S CHOOL OF M EDICINE AND P UBLIC H EALTH,
Department of Human Oncology, Madison, USA
Purpose: Cone Beam CT (CBCT) is increasingly used to verify patient setup accuracy during radiotherapy for lung cancer. However, standard CBCT
images contain much more than just the position information. This study
shows the feasibility of quantifying density changes in the healthy lung tissue
from CBCTs during the radiotherapy course and that these changes correlate
to the locally delivered dose.
Materials: 26 lung cancer patients treated with IMRT to 60 or 66 Gy in 2 Gy

T UESDAY, M AY 10, 2011
fractions were randomly selected from our patient database. Patients withgood performance status (13/26) were treated with concomitant chemotheraphy. Exclusion criteria were lung atelectasis or pleural exudate during thetherapy course. A total of 245 CBCTs were acquired at specific fractions
throughout the treatment course for the patients in this study. All CBCT scans
were deformably registered to the planning CT. The local change in densityof the healthy lung tissue was estimated by subtracting the first CBCT fromthe other scans. These changes were related to the locally delivered dose as
calculated in the treatment plan.
Results: The figure shows density changes in the healthy lung at the 10th ,20th and 30th fraction averaged over all patients as function of the locallydelivered dose. The error bars on the graph are standard errors estimatedby boot strapping and documents a dose response relationship at the endof the treatment course. For the 30th fraction statistically significant increasein the signal exist between lower and higher doses (signed Wilcoxon test
p<0.03). The accumulated signal over all doses observed at the 30th fraction
is correlated to the signal observed at the 10th and 20th fraction (Spearman’srank correlation test R=0.56, p= 0.004 and R=0.64, p= 0.001, respectively).
On average the lung density was found to increase significantly between fromthe 10th to the 30th fraction as well as from the 20th to the 30th fractions(signed Wilcoxon test p= 0.005 and p=0.002, respectively). A study of thepossible association between measured CBCT density changes and clinicaladverse events is in progress. If such a correlation is established it would
be possible to predict the toxicity outcome of some of the patients quite early
during the therapy course.

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results were compared to the time needed to position the patient using kV-MV
imaging and marker-matching during the other sessions.
Results: The global accuracy compared to the marker-match repositioning
was -0.09 (SD=1,30), -1.28 (SD= 2,55) and -0.62 (SD=2,11) mm in lateral,longitudinal and vertical axis respectively (N=83). For 3 patients the mean
deviation in one of the axes exceeded 3 mm. This could be explained by theTracer location being far from the center of mass of the other fiducials and due
to rotation and/or shrinkage of the prostate. A disadvantage compared to 3 or
4 fiducial markers is that deformation and shrinkage of the prostate cannot be
detected with this system. No migration of the Tracers was observed in anyof the patients.The mean time to position the patient to the isocenter using
the RealEye System was 118 sec (SD=36) (N=99), compared to 358 sec(SD=128) (N=470) with marker-matching. This translates into a significant
reduction in overall time per treatment session of about 240 seconds.
Conclusions: The Navotek system is a fast and reliable positioning system
which reduces the overall time per treatment session by 4 minutes comparedto the standard IGRT online marker-match system. Therefore, the Navotek
system offers an excellent alternative for the currently used matching systems in daily monitoring, even in between irradiation fields during the samesession. For low energy beams, monitoring during treatment even for Rapid
Arc is also possible. The reliability of the system is, as for every other fiducial
marker, dependent on the position of the tracer in the prostate.
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INTERFRACTION DISPLACEMENT OF PELVIC LYMPH NODESDURING RADIOTHERAPY FOR BLADDER CANCER
M. Kamphuis1 , N. Van Wieringen1 , L. Elfering1 , A. Bel1 , M. Hulshof1
1

ACADEMIC M EDICAL C ENTER, Department of Radiotherapy, Amsterdam,
Netherlands

Conclusions: Density changes in healthy lung can be assessed from standard CBCT scans made for positioning the patient. The density change correlates with dose delivered locally and the signal measured at the 10th and20th fraction can be related to the signal at the end of treatment. The clinicalimplications of these findings needs to be established, but this assay could
potentially form the basis for adapting the therapy plan during the treatment
course.

RTT Proffered Papers 4: Imaging for Treatment
Planning and Position Verification

Purpose: At the radiotherapy department of the Academical Medical Center of Amsterdam patients with inoperable solitary bladder cancer are treatedusing IMRT in 20 fractions of 2,75 Gy to the primary tumour, and 2 Gy electively to the pelvic lymph nodes. A concomitant boost technique is used.
Lymph nodes, not visible on CT-scan, are delineated using guidelines of Taylor (2005). A 1,0 cm CTV-PTV margin is used to account for several uncertainties, often resulting in large treatment volumes. To safely limit margins
we need to quantify the error sources. In case of (perfect) online correctionof translational set-up errors (registration on the bony anatomy), the motionof the lymph nodes and rotations of the pelvic area will be the most important factors for determining the required margin. The aim of this study is toevaluate these two uncertainties.
Materials: Ninety-four Conebeam CT-scans of 7 supine positioned patientswere selected based on the presence of calcifications in the pelvic arteries.
These calcifications were used as a surrogate for the position and mobility of
the lymph nodes. Seven areas in the pelvic lymph nodes were distinguished:
the bifurcation, a.iliaca communis (left and right), a.iliaca interna (left andright) and the a.iliaca externa (left and right). First an automatic registration
to the bony anatomy was performed, quantifying pelvic rotations. After that,the calcifications were registered manually. The mobility of calcifications (i.e.
lymph nodes) was measured relatively to the bony anatomy and is presented
in terms of random (RMS of the SD’s of all patients) and systematic errors(SD of the means per patient).
Results: For every pelvic area both systematic and random error of lymph
node displacements were about 0,1 cm (table 1). Largest random and systematic error were found in the Z-axis and were all below 0,2 cm. Rotations
were largest around the X-axis and ranged from 355,0 to 5,8 degrees. A
maximum average rotation of 2,5 degrees was found in the Z axis.

327 oral
A RELIABLE AND FAST (REAL-TIME) POSITIONING SYSTEM(NAVOTEK®) REDUCES THE OVERALL TIME PER TREATMENTSESSION.
J. Verstraete1 , L. Van den Bergh1 , W. de Kruijf2 , S. Hol2 , B. Wijsman2 , R.
Davits2 , B. Corn3 , F. Van den Heuvel1 , P. Poortmans2 , K. Haustermans1
1
L EUVENS K ANKER I NSTITUUT (LKI), U NIVERSITY H OSPITAL G ASTHUIS BERG , Leuven, Belgium
2
D R . B ERNARD V ERBEETEN I NSTITUUT, Tilburg, Netherlands
3
T EL AVIV M EDICAL C ENTER, Tel Aviv, Israel
Purpose: To evaluate patient set-up time and positioning accuracy of aninvestigational gantry-mounted tracking system (RealEye, Navotek Medical
Ltd., Israel) using an implanted low-activity iridium-192 source in the prostate(Tracer, Navotek Medical Ltd.).
Materials: In two institutions, this EC-approved study included a total of
20 patients that were implanted with the Tracer alongside standard fiducial
markers. Patient positioning accuracy with the RealEye tracking system wascompared during 5 sessions (throughout the whole radiotherapy treatment)with the standard on-line verification procedure based on the implanted gold
seeds, using kV and/or- MV images.Secondly, time measurements were performed starting from the moment the patient was placed on the treatment
couch until correct isocentric positioning using the RealEye System. These

Conclusions: The interfraction motion of pelvic lymph nodes relative to thebony anatomy, are below 0,2 cm. Rotations of the pelvis on the other handare substantial, resulting in lymph node displacements of maximal 1,3 cm.
Because the lymph nodes form an elongated area, the impact of these rotations on the dose coverage of the CTV should be explored.

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331 oral

AUTO-ADAPTIVE, APERTURE-BASED IGRT, A³IGRT
P. Scherer1 , H. Deutschmann1 2 , G. Kametriser1 , F. Sedlmayer1 2
P RIVATE U NIVERSITY C LINIC S ALZBURG, University Clinic for Radiotherapy
and Radio-Oncology, Salzburg, Austria
2
S ALZBURG PARACELSUS U NIVERSITY, rad ART Institute for Research andDevelopment of Advanced Radiation Technologies, Salzburg, Austria

HOW TO IMPROVE IMAGE QUALITY OF ELECTRONIC PORTALIMAGING DEVICES WITH MLG CALIBRATION AND TEMPERATURECORRECTION
S. Huber1 , B. Mitterlechner2 , M. Mooslechner1 , F. Sedlmayer12 , H.
Deutschmann1 2
1
PARACELSUS M EDICAL U NIVERSITY, Institute for Research and Development on Advanced Radiation Technologies (radART), Salzburg, Austria
2
U NIVERSITY C LINIC S ALZBURG, University clinic for radiotherapie andradio-oncology, Salzburg, Austria

1

Purpose: The aim of image-guided radiotherapy (IGRT) is an exact application of the dose and a reduction of CTV-to-PTV margins respectively. A lot of
influencing factors have to be taken into account to prudentially reduce thesemargins and therefore reduce side effects without compromising on tumor
control. aIGRT can reduce some of these factors.
Materials: The method derives from the assumption that if the detected deviations can be described though transformations which can be used to adjust the patients, then the inverse corrections can be applied on the 3D-CTV
which can afterwards be used to recalculate aperture positions. 4 implanted
gold-markers are used to reconstruct the exact position (translations, rotations and dilations) of the prostate out of two perpendicular planar kV-images.
These transformations are then applied to the structure set (prostate, seminal vesicles,...) in 6 degrees of freedom. Further the shapes of the intensity
modulated radiotherapy (IMRT) segments and MLCs and Jaws are reshaped
respectively according to the transformed structures.
Results: Due to the adaptation of the aperture aIGRT can correct for translations as well as rotations without movement of the patient. This adaptationof the aperture can be done within a few seconds and therefore allows online
correction and can be easily implemented into daily routine on the treatment
machines. An individualisation of margins for patients with large intra-fraction
motion is possible as well.
Conclusions: aIGRT is a tool that allows online adaptation of IMRT
fields/segments. It allows to correct for 6 degrees of freedom of internal organ motion and an additional reduction of margins. Promising aspects for the
future are the possibility of a correction of detected intra-fraction motion areeven tracking.
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A COMPARISON OF TREATMENT AND IMAGE MATCH TIME FOR
THREE DIFFERENT IGRT – PROCEDURES IN RT OF BLADDERCANCERM. B. Ellegaard1 , A. Schouboe1 , A. Vestergaard2 , L. P. Muren2
1

A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
Purpose: New image guided radiotherapy (IGRT) techniques led to clinicalimplementation of different match procedures in radiotherapy of bladder cancer patients. In this study we compared time consumption of the following
three match procedures: A) 2D match based on orthogonal 2D KV-images
with an On Board Imager (OBI). B) 3D volumetric match based on bony
anatomy in cone beam CT (CBCT), and C) 3D volumetric match based on
injection of the contrast medium Lipiodol as a liquid radio-opaque fiducial
marker as seen in CBCTs. The Lipiodol was injected into the bladder wall in
the periphery of the tumour for image-guided boost to the tumour. The purpose of this study was to compare the match evaluation time (MET) as wellas the total fraction delivery time (FDT).
Materials: We included a total of 49 bladder cancer patients that received in
total 1229 fractions in the period June 2008 to September 2010. The first fraction of each patient was not included in the analysis. Three different match
types with 60 Gy per 30 fractions with 5 fractions per week per patient wereanalyzed related to MET. Group A: 9 patients treated with IMRT using matchprocedure A. Group B: 33 patients treated with Volumetric Arc therapy (VMAT)or Intensity modulated radiotherapy (IMRT) using match procedure B. Group
C: 7 patients treated with VMAT boost, 10 Gy in 5 fractions with match procedure C. The definition of MET was the time from image acquisition until thedelivery of the first field. FDT was defined as the time from the patient record
was loaded onto the treatment console until it was closed and saved to the
database. Time measurements were taken from the ARIA database (Varian
Medical Systems, Palo Alto (CA)) and analyzed in Intercooled STATA version
10 and Microsoft Office Excel 2007.
Results: Mean MET were for group A 5.36 min (SD 3.40 min), group B 2.26
min (SD 1.43 min) and group C 5.03 min (median). Mean MET was significant
longer in group A compared to group B (p<0.0001). For the group with thelargest number of patients (group B) a learning curve was observed with significantly reduction of FDT (p<0.0001) and MET (p=0.0002) during the study
period.
Conclusions: Using CBCT and bony anatomy match it is possible to reduce MET significantly compared with the use of OBI. As expected, MET
was higher when using match on Lipiodol as compared to CBCT and bony
anatomy match. Gaining experience was observed to reduce MET and FDT
for CBCT based bony anatomy match.

Purpose: Amorphous silicon flat panel detectors are widely used in radiotherapy for on board kV and MV imaging tasks. Imaging of anatomy for patient setup-corrections or port verifications as well as imaging of unabsorbed
beams for fluence verification in IMRT or for calibration procedures and linac
constancy checks require a linear dose response of pixels or perfect stabilityof system in order to achieve good and reproducible results. However, due toirradiation damages, aSi:H MV panels are aging. They require re-calibrations
that fail after a certain period of clinical use. Typically, MV panels have tobe replaced after 18 months due to increasing but inpredictable noise andsubpanel-related artefacts that change during the day. Especially at low MU
imaging applications (check film), during the startup of beams or at lower
doserates, these artefacts become the main problem of aSi:H imaging, limiting accuracy of calibration tasks as well as overall image quality and clinicalusability.
Materials: We developed a novel approach to separate the subpanel-related
artefacts, which can be explained by insufficient radiation hardness of amplifiers in readout electronics, from radiation damages in the active area. While
first artefacts are line specific, second become dominant in areas more often irradiated, typically in the center of the panel. Both aging effects introduce non linearities in pixel response to doserate, which are of utmost importance at irradiation with lower doserates (<50 MU/min). Therefore, two-pointcalibrations (gain / offset) are not sufficient for appropriate correction of native
panel images. A multi-level gain correction approach promises better results
and has the potential to prolongue overall panel lifespan. However, our investigations showed that non-linearities change during the day. We found thatchanges in the offset value after irradiation will have an effect on gain values,
the older a panel, the worse the stability of gain images acquired by flood field
irradiations. The same correlation was seen, if the temperature was changed:
At increasing temperatures, offset values are typically increasing, while gain
values might decrease for a majority of pixels. Considering the sources of
non-linearities (amplifiers of readout and damages of photo diodes / TFT),
we found a method to predict and correct the related artefacts by means of atemperature related multi level gain correction.
Results: aSi:H image quality can be improved significantly by advanced corrections of native image without a need to re-calibrate the device frequently.
Temperature of amplifiers and active area can be derived from ghost-free offset images (analysis of non-irradiated panel borders) directly and used as
an input for temperature related multilevel gain correction. Life span can beat least doubled: In Salzburg, we work with 4 year old panels, that havebeen in the beam for most patients on a daily basis. After advanced corrections, acquisition of dosimetrical meaningful images (used for MLC calibration, symmetry-, homogeneity- or monitorchamber-checks or other QA tasks
in IMRT verification) as well as of clinically acceptable images (setup or verification tasks) is still possible.
Conclusions: By separation of panel properties from radiation properties
during calibration, a multi level gain acquisition has only to be performed once
per panel, independent from energies used. By separation from readoutrelated aging artefacts from active area artefacts and correlation of these
artefacts with panels temperature, re-calibration intervals can be significantly
reduced and life span of costly devices prolongued.
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QUANTIFICATION OF DIFFUSION-WEIGHTED MRI FOR TREATMENT RESPONSE ASSESSMENT IN HEAD AND NECK CANCER
H. Van Herck1 , S. Nuyts1 , V. Vandecaveye1 , M. Lambrecht1 , R. Hermans1 ,F. De Keyzer1 , P. Suetens2 1 , P. Slagmolen1
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Leuven, Belgium
2
C ATHOLIC U NIVERSITY OF L EUVEN, Medical Image Computing (ESAT/PSI),
Faculties of Medicine and Engineering, Leuven, Belgium
Purpose: Radiotherapy (RT) is one of the cornerstones in the treatment ofhead and neck cancer (HNC). Locoregional control is an important problem
in this field. Recently, diffusion weighted MRI (DWI) has shown promising
results in identifying treatment resistant tumors, of which precise visualization might help deliver the treatment more accurately. Although registration
between different modalities and time points remains a challenging task, apossible solution is proposed here.
Materials:

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receiving 10 Gy were respectively 71.5% (12) with the SIB IMRT at 72 Gy
and 80% (13) with 3DRTC 60 Gy (p=0,0959).The mean percentages (SD) of
healthy brain volume receiving 40 Gy were statistically different , being 30%(13) with 3DRTC 60 Gy and 17,7% (7) with SIB IMRT 72 Gy (p=0,0026).
Conclusions: We developed a robust and reliable image processing protocol
for MR spectroscopy integration to TPS. The dosimetric study comparing 60
Gy conventional RT and 72 Gy SIB IMRT guided by MR spectroscopy showedthat the doses to healthy surrounding brain were lower with increased dose
SIB IMRT up to 72 Gy than with standard 60 Gy conventional RT. A randomised multicentric clinical trial is now starting comparing conventional RTwith SIB IMRT guided by MR spectroscopy.

Before the start and 2 weeks into RT, 5 patients underwent an anatomical MRI
with DWI. Two T1-weighted images (T1pre and T12w) and two apparent diffusion coefficient maps (ADCpre and ADC2w) were used for analysis (Figure1).For the evaluation of treatment-induced changes after 2 weeks, variations
in patient position and organ deformations as well as modality-specific artifacts have to be taken into account. As a way of countering especially the
first two distortions, a combination of a rigid and nonrigid mutual informationbased registration using B-splines [1,2] was performed (Figure 1). Next, togreatly reduce artifacts in the ADC maps and remaining smaller deformations, two point-based thin-plate spline (TPS) warped registrations [3] wereapplied with markers manually placed on distinct landmark positions in images ADC2w (after the previously mentioned rigid and nonrigid registration),
ADCpre and T1pre.
Results: The presented registration method was tested on head and neck
MRI’s, acquired from 5 patients, on which corresponding anatomical structures were delineated. Corresponding to literature [1,2], the result of the rigid
and nonrigid registration showed, for these 5 patients, a strong visual correlation with the image T1pre, both in terms of image contours and internalorgan structure. After marker-based registration, the deformed versions of
the above mentioned delineations (e.g. spinal canal, tumor, &) fell within theircorresponding unregistered areas, using an average of 20 markers.
Conclusions: Preliminary results demonstrate that automatic B-spline registration using maximization of mutual information followed by semi-automatic
registration using manually placed markers can be used as a tool to assess
RT-induced and patient related changes between different imaging modalities
at different time points. This can help us identify anatomical regions resistant to treatment.References: [1] F. Maes, A. Collignon, D. Vandermeulen,
G. Marchal, and P. Suetens.Multimodality Image Registration by Maximization of Mutual Information. IEEETrans. Med. Imag., 16(2):187-198, 1997.[2]M. Modat, G.R. Ridgway, Z.A. Taylor, M. Lehmann, J. Barnes, N.C. Fox, D.J.
Hawkes and S. Ourselin. Fast free-form deformation using graphics processing units. Comput. Meth. Prog. Bio, accepted. [3] F. L. Bookstein, Principal Warps: Thin-plate Splines and the Decompositionof Deformations. IEEE
Trans. Pattern Anal. Machine Intell., 11: 567585, 1989.
333 oral
GLIOBLASTOMA DOSE PAINTING WITH IMRT SIMULTANEOUS
INTEGRATED BOOST GUIDED BY MR SPECTROSCOPY.
A. Laprie12 , L. Vieillevigne1 , S. Ken21 , C. Supper1 , F. Thomas1 , X.
Franceries2 , L. Simon1 , G. Hangard1 , J. A. Lotterie2 , R. Michel1 , M.
Delannes1 , I. Berry2 , C. Pierre2 , E. Moyal-Cohen-Jonathan1
1
I NSTITUT C LAUDIUS R EGAUD, Toulouse, France
2
INSERM UMR 825, Toulouse, France
Purpose: In order to prepare an upcoming multicentric clinical trial on dose
escalation for glioblastoma , we developed an integration technique of MR
spectroscopy to TPS. Then we performed a dosimetric study comparing conventional RT and dose-escalated MR-spectroscopy-guided SIB IMRT, in order to define the best ballistic choices for PTV dose conformity and characterize healthy brain sparing.
Materials: We used 3D MR spectroscopy, which was described as predictive
for the site of post radiotherapy relapse for glioblastoma, MRI and planning
CT of 19 glioblastoma patients included in a previous prospective trial of aradiosensitizer and conventional 3D RT.First, as MR spectroscopy metabolic
maps are not delivered in a DICOM format, we developed an automated image processing tool for MR spectroscopy data integration onto planning CT,
and performed the same processing 10 times for each of the 19 patients inorder to test reproducibility.Then we performed a dosimetric study for eachpatient, comparing doses to healthy brain with two different treatments : 1)with conventional 3DCRT at 60 Gy /2 Gy fractions targeted to contrast enhancement (CE) with a 2cm margin 2) with SIB IMRT (60Gy/ 2gy/fractions on
CE + 2cm and 72 Gy/2.4 Gy by fraction on the boost), the boost corresponded
to the MR spectroscopy abnormalities (Cho/NAA ratio>2 with a 1cm margin). The V10 Gy and V40 Gy to healthy brain (brain tissues minus PTVs) werecompared.
Results: The image processing protocol for the coregistration of MR(anatomic maps) and MR spectroscopy (metabolic maps of Cho/NAA>2) toplanning CT, included global normalization and volume segmentation. The
results of the reproducibility study showed means ( with standard deviationsSD) of translation parameter to be 0.05 cm ( 0.03) and rotation parameter tobe 0.92 degree (0.7). The mean percentages (SD) of healthy brain volume

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S YMPOSIUM

Wednesday, May 11, 2011
Symposium
30 years of radiation oncology in Prostate cancer- What is the evidence-based that ‘we’ have created?
334 speaker
DOSE ESCALATION: HOW BIG IS THE ADVANTAGE?
D. P. Dearnaley1
1
I NSTITUTE OF C ANCER R ESEARCH, Academic Radiotherapy, Sutton,
United Kingdom

International randomised controlled trials of dose escalated radiotherapy
have included more than 4,000 patients. Overall there is consensus that biochemical (PSA) control of disease is improved with an odds ratio for failureof approximately 0.6 in favour of high dose treatment and "number needed
to treat" (NNT) to prevent 1 failure of about 10. There is general agreementthat there is little heterogeneity of benefit between low, intermediate and highrisk groups of patients. Improved PSA control leads to a reduction or delay in time to salvage hormonal therapy, however data on the development
and metastases, and overall and prostate cancer specific survival remains
immature. Further long term follow up of trials is required to confirm that
improved biochemical control translates into improved overall outcome. Trial
meta-analysis is desirable. Improved PSA control comes at the cost of anincrease in bowel (but probably not bladder) side effects - and the NNT for
increased toxicity is again approximately 10. Refinements of radiotherapy
techniques should reduce side effects whilst maintaining benefit. Challenges
remain in determining the appropriate use of combined modality treatment
with radiotherapy and androgen suppression/blockade, the use of modest or
extreme hypofractionation, functional imaging and dose painting, and the development of biomarkers to personalise treatment predicting outcome of different dose/fractionation schedules on an individual basis. Further large clinical trials and translational research initiatives are addressing these issues
with the prospect of developing a sound evidence base for more effective,
safer and convenient radiotherapy treatments in the future.
335 speaker
PROSTATE CANCER: ADJUVANT ANDROGEN DEPRIVATIONTHERAPY IN THE ERA OF NEW TECHNOLOGIES AND DOSEESCALATION
M. Bolla1
1
CHU DE G RENOBLE - A.M ICHALLON, Radiation Oncology, Grenoble,
FranceRadiotherapy plays a significant role in the treatment of localized and/or locally advanced prostate cancer (PCa), all the more as individual or mass
screening increases the opportunity to diagnose early prostate cancers andenables the patients to choose a conservative treatment with brachytherapy
or intensified modulated radiotherapy (IMRT), should it be possible. Nevertheless, according to prognostic factors, infra-clinical disease may be present
outside the pelvis, requiring androgen suppression to prevent the occurrenceof distant metastases, which may impact on health related quality of life. Feasibility of IMRT and brachytherapy, multidisciplinary approach and guidelines(1), allow us to tailor the therapeutic strategies within the frame of a large
range of possibilities.
Low risk localized prostate cancer : T1c-2a, Gleason < 6, PSA< 10 ng/ml-Brachytherapy for those patients who meet the eligibility criteria,-IMRT with dose escalation (78 Gy)
Intermediate risk localized prostate cancer : T2b, Gleason 7, PSA <20 ng/ml-There is no phase III randomized trial comparing EBRT with dose escalation(80 Gy) versus the classic approach represented by the d’Amico trial: 3DCRT (70 Gy) plus 6 months of a complete androgen blockade which has
shown a significant increase of the 8-year overall survival with respect to
EBRT alone (70Gy) (p<0.001(1). The 94-08 RTOG trial has also shown asignificant gain of the 12-year overall survival (p=0.03) in favor of the combination approach with EBRT (66.6 Gy) plus 4 months complete androgenblockade (2).
-IMRT with dose escalation (80 Gy) or a combination of IMRT (46 Gy) + low
dose rate (120 Gy) or high dose rate brachytherapy (3)High risk localized prostate cancer : T2c, or Gleason 8-10, or PSA >20 ng/ml-Short term (6 months) androgen suppression with IMRT (78 Gy)
Locally advanced prostate cancer T3-4 N0-X M0-Patients classified as T3 with Gleason 6 and PSA <10 ng/ml or patients suffering from co-morbidities, have to receive EBRT with dose escalation with ashort term androgen suppression (6 months).
-Other patients must receive long term androgen suppression (3 years (4)with 3D-CRT +/-IMRT; dose escalation is recommended (5)( 6).
-Irradiation of pelvic lymph nodes is recommended since it was used in all

W EDNESDAY, M AY 11, 2011
the trials which have shown a significant increase of overall survival in locallyadvanced PCa with the combined approach (7,8,9).
Consensus on pelvic lymph nodes CTVs (10) makes possible the increase of
the dose to the pelvic lymph nodes with the use of IMRT.
References
1 Heidenreich A, Bellmunt J, Bolla M et al. EAU Guidelines on Prostate Cancer. Part 1: Screening, Diagnosis, and Treatment of Clinically Localised Disease. Eur. Urol . 2011 ; 5 9 : 6 1 7 1
2 D’Amico A, Renshaw AA, Loffredo M, Kantoff PW. Androgen suppression
and radiation vs radiation alone for prostate cancer; a randomized controlled
trial. JAMA 2008 Jan;299(3):289-95
3 Stock RG, Yalamanchi S, Hall SJ, Stone NN. Impact of hormonal therapy
on intermediate risk prostate cancertreated with combination brachytherapy
and external beam irradiation. J Urol. 2010;183(2):546-50.
4 Bolla M, de Reijke TM, Van Tienhoven G, et al. Duration of Androgen
Suppression in the Treatment of Prostate cancer. N Engl J Med 2009; 360:
2516-27.
5 Zelefsky MJ, Yamada Y, Kollmeier MA, Shippy AM, Nedelka MA. Longterm outcome following three-dimensional conformal/intensity-Modulated external beam-beam radiotherapy for clinical stage T3 prostate cancer. Eur
Urol. 2008:1172-1179.
6 Zapatero A, Valcarcel F, Calvo FA et al. Risk-adapted androgen deprivationand escalated three-diomensional conformal radiotherapy for prostate cancer: does radiation dose influence outcome of patients treated with adjuvant androgen deprivation? A GICOR study. J Clin Oncol 2005. 23:6561-6568.
7 Bolla M, Collette L, Blank L, et al. Long-term results with immediate androgen suppression and external irradiation in patients with locally advanced
prostate cancer (an EORTC study): a phase III randomized trial. Lancet 2002;
360: 103-08.
8 Horwitz EM, Kyounghwa B, Hanks GE, et al. Ten-year follow-up of Radiation Therapy Oncology Group Protocol 92-02: A phase III trial of the durationof elective androgen deprivation in locally advanced prostate cancer. J Clin
Oncol 2008; 26: 2497-504.
9 Pilepich MV, Winter K, Lawton CA, et al. Androgen suppression adjuvant
to radiotherapy in prostate carcinoma-Long-term results of phase III RTOG
85-31. Int J Radiat Oncol Biol Phys 2005; 61: 1285-90.
10 Lawton CA, Michalski J, El-Naqa I et al. RTOG GU radiation oncology specialists reach consensus on pelvic lymph node volumes for high-risk prostatecancer. Int J Radiat Oncol Biol Phys 2009; 74: 383-387.
336 speaker
SALVAGE OR ADJUVANT RADIATIONTHERAPY AFTER PROSTATECOMY
T. Wiegel1
1

U NIV.- K LINIK U LM, Ulm, Germany

Abstract not received.

W EDNESDAY, M AY 11, 2011

S YMPOSIUM

Symposium

338 speaker

30 years of radiation oncology & Normal tissue What is the evidence that ‘we’ have created?

PATHOGENESIS AND REPAIR OF NORMAL TISSUE DAMAGE
W. Dörr1
1
T ECHNISCHE U NIVERSITÄT D RESDEN, Dresden, Germany

S 135

337 speaker
FRACTIONATION: CLINICAL APPLICATION OF RADIOBIOLOGICALKNOWLEDGE
M. Joiner1
1
WAYNE S TATE U NIVERSITY, Radiation Oncology, Detroit, USA
Biological effect and physical dose are non-linearly related. This was implicitly recognized very early in the development of radiotherapy, and led to thepower-law equations which dominated thinking for several decades. Deficiencies in the power-law description were identified even as early as the 1960’s,
and in the 1970’s and 80’s a massive amount of experimental work on many
newly-developed models of normal-tissue injury in rodents and pigs, showedthat ln(Surviving Fraction) is much better described by a second-order polynomial in dose, the well-known Linear-Quadratic (LQ) equation. The LQ description has since been thoroughly tested in the clinical domain. LQ is thesimplest mathematical description of a non-linear relationship and though empirical in nature, it has nevertheless been subject to many attempts to connect
with our understanding of how radiation injury is produced and repaired at thecell and molecular level, yet any meaningful and clinically useful link in thisrespect has remained largely elusive.
LQ deals specifically with the relationship between total dose and dose per
fraction, and with interfraction interval using the Incomplete-Repair derivativemodel. The relationship between total dose and overall treatment time, originally included in the power-law models in a manner that didn’t match actual
clinical observations, is an even more complex relationship dependent on the
different underlying radiobiology of different tissues even within the apparently same category of early-reacting or late-reacting tissues, distinguishedby respectively a "high" or "low" ratio of α/β in the LQ equation. Overall timeis therefore better handled independently of LQ. Prediction of tolerance toretreatment is an even more complex issue where our radiobiological understanding is earlier in development and useful models are not yet to hand.
A straightforward but untested hypothesis for the different α/β values forearly- and late-reacting tissues, is that a naturally low α/β for a target cell
population is smoothed out to a higher value as the sum of the responses
of different proliferative subpopulations, and different phases of the cell cycle that these are in. This same explanation could also be applied to the
responses of malignancies in the head and neck and in the lung, also addingin the additional response variation of cells at various levels of hypoxia inthese sites. Importantly, it is now evident that in some malignancies, notably
prostate and breast, clinical data indicate a low α/β which may reflect more
uniformity in response perhaps more characteristic of early-stage disease.
This has resulted in new efforts to test hypofractionation which have also
been enabled by the better dose localization achievable with image-guided
IMRT. Also of note is the recent connection made between outcome of radiotherapy and HPV status in oropharyngeal cancer, which implies a possible
difference in α/β , and hence treatment strategy, between these tumor subtypes.
There is evidence that the LQ model becomes less reliable at doses per fraction <1 Gy, due to possible low-dose hyper-radiosensitivity, and also at >6 Gy
per fraction for reasons not yet understood. Though, it is axiomatic that LQ
would indeed overestimate effect at very high doses because the effective D0
would become unrealistically low. This makes the outcome of hypofractionated regimes less predictable: using LQ at high doses per fraction would beplaying safe in predicting toxicity of hypofractionation, while overestimating
the effect on the target malignancy, noting that possible hypoxia in a tumor
also limits the effectiveness of large dose fractions.
The EQD2 and BED, products of the LQ equation, have proven valuable inbeing able to simply intercompare different fractionation schedules within a"common currency". To account additionally for dose variations within a target and adjacent structures, and also for the effect of volume irradiated, dosecan be spatially integrated to provide an equivalent dose that if given uniformly across the treatment volume would result in the same tumor control
or complication probability, as the non-uniform dose actually administered.
An example of this procedure is the Generalized Equivalent Uniform Dose(gEUD). We have demonstrated that if this calculation is performed by first
converting physical dose to biologically effective dose voxel by voxel, andthen integrating those voxel EQD2 values to obtain gEUD2, we can significantly differentiate between treatment plans which would appear similar on
the basis of physical dose alone. We expect that making these enhancements available to the treatment planning systems could provide improved
therapy particularly in patients with substantial biological heterogeneity within
their disease.

The radiation response of normal tissues encompasses changes in tissuespecific cell populations (parenchyma), connective tissue (fibroblasts) andvascular components (capillaries), as well as direct or secondary reactions of
the immune system (macrophages). Normal tissue radiation effects are not
only a consequence of cell kill, but are also subject to complex sequencesof post-irradiation "damage processing" events. The radiation sensitivity ofnormal tissues is largely independent of their proliferative activity, while thetime to clinical manifestation of their radiation response is clearly dependingon their proliferative and biological structure.
For early radiation effects, e. g. in oral or gastrointestinal epithelia or the epidermis, the parenchymal reaction is dominating their clinical manifestation.
In these tissues, radiation-induced impairment of cell production in the germinal tissue compartments, in face of ongoing cell loss at its physiological rate,
eventually results in epithelial denudation and protective barrier breakdown.
One consequence is bacterial infiltration, with a risk of local and systemic infections. The latent time for these early radiation effects is depending on the
biology of the tissue (in particular the turnover time, i. e. the time interval inwhich all cell are physiologically replaced once), and - over a wide range independent of the radiation dose.
Late radiation sequelae predominantly present as radiation fibrosis or atrophy,
based on the orchestrated response of the above mentioned tissue components. Radiation induces parenchymal hypoplasia through the sterilization oftissue-specific cells, changes in the vascular network with a pronounced lossof capillaries and telangiectasia, as well as differentiation of fibroblasts into fibrocytes with increased collagen deposition. Activation of macrophages andother immune cells directly by irradiation or indirectly through the radiationinduced changes in paracrine signaling significantly contributes to tissue remodeling. Late radiation responses are usually considered progressive andirreversible. The latent time to the onset of clinical changes is inversely dependent on the radiation dose. Therefore, with more conformal irradiation
techniques that are associated with an expansion of the volume exposed to"moderate" doses, late reactions may be expected later compared to conventional radiotherapy.
The morphological manifestation of radiation effects in normal tissues islargely confined to the volume irradiated, depending on the local dose inthis volume. The clinical consequences, however, are defined by both thestructure of the tissue and the size of the exposed volume, as well as by the
localization of the irradiated volume within the organ. A number of models
have been developed to describe this volume effect, which yet need to be
improved considerably. This requires comprehensive and precise collectionof information on dose distributions and manifestation of side effects.
"Repair" in the present context must be interpreted as a composition of several processes: (i) recovery, as the basis of the fractionation effect, (ii) repopulation, defining the effect of overall treatment time, and (iii) long-term restoration, characterizing the re-irradiation tolerance of tissues and organs.The fractionation effect, describing the increase in tissue tolerance (or iso-effective
doses) with a decrease in dose per fraction, may be described by the linearquadratic model of radiation effects. This effect is most pronounced in late
responding tissues, as indicated by their low -value in the linear-quadraticmodel. In early responding tissues, a compensatory regeneration response(repopulation) - already observed during the course of radiotherapy - results
in a significant increase in radiation tolerance with increasing overall treatment time. Repopulation is based on a complex re-organization of the proliferative structure of the tissue, including accelerated stem cell divisions, production of additional stem cells, and residual proliferation of doomed cells.
Long-term restoration of tissues may be based on surviving (stem) cells within
the irradiated volume or by migrating cells from un-irradiated tissue, as wellas on other mechanisms. However, also progression of the initial damage or
secondary damage (epithelial atrophy, chronic inflammation) may result fromlater vasculo-connective tissue damage can occur. There are very big differences in re-treatment tolerance between tissues, and even for different typesof damage within one tissue. No general formula can be applied to estimate
re-treatment tolerance, although pre-clinical data and clinical experience canbe used to provide approximate guidelines.
A broader illustration of the various aspects of normal tissue pathogenesisand "repair" mentioned above can be found in "Basic Clinical Radiobiology,
4th edition", by Joiner and Van der Kogel, 2009.

S 136

T EACHING LECTURE

Teaching lecture
339 speaker
THE TUMOR MICRO-ENVIRONMENT
A. van der Kogel1
1

R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Biology, Nijmegen,
Netherlands
Abstract not received.

340 speaker
PHYSICAL PROCESSES IN PROTON AND ION THERAPY
L. Sihver1 23
1
C HALMERS U NIVERSITY OF T ECHNOLOGY, Applied Physics, Göteborg,
Sweden2
T EXAS A&M U NIVERSITY, Nuclear engneering, College Station, USA
3
R OANOKE C OLLEGE, Physics, Salem, USA
In contrast to conventional photon beams, the absorbed dose of protons
and ions increases along the penetration depth and shows a sharp maximum (Bragg peak) at the end of the particle range, followed by a sharp decrease behind it. This makes beams of protons or heavy ions the preferredchoice over conventional photon beams for deep seated tumors. The lateral and range scattering decreases quadratically with the atomic number ofthe charged particles, which favours light ion beams compared to protons.
The RBE of ions is also superior to that of conventional radiotherapy beams,
using x-ray and γ -ray, even in conditions of hypoxia. Therefore radiation
resistant tumors that have a high repair capacity against photon irradiation
become sensitive for treatment with ions beams. However, in order to estimate the biological effects of proton and ion beams, accurate knowledgeof the physical, chemical and biological processes of the charged particles
in human tissue and organ is necessary. When high energetic ions collidewith the human cells, a new mixed radiation field is created. This new radiation field consists of projectile fragments, which have lower charges thanthe original beam particles, mixed LET and longer ranges, slow moving target
fragments. These target fragments have lower charges than the target atom,high LET, and shorter ranges than the primary particles and therefore higher
local biological effect. There will also be recoil movements of the remnantsof target atoms, and free electrons and many other particles are produced.
The nuclear reactions of the ions with the human targets depend on theirenergies. In the energy interval of therapeutic interest, interaction mechanisms go from fragmentation at higher energies to more complex ones at thelower energies. Depending on the nuclear structure of the interacting ionsand on the impact parameter, the low energy reaction mechanisms vary from
Coulomb Scattering to deep inelastic processes and complete/incomplete fusion. The difference in biological action between charged particles and photons is mainly due to the different spatial distribution of the electrons and ionization events along the tracks of the particles. Photons produce stochastic
distributed Compton, photo and pair electrons, while protons and ions dissipate their energies along their trajectories, ionizing the target atoms andproduce free electrons. These so-called δ -electrons create secondary andtertiary ionization processes around the ion track. The maximal penetrationof δ -electrons from the track core is proportional to the energy of the impinging particles and 70-80 % of the dissipated energy is used for the ionization
process, and only 10 to 20% are left for target atom excitation. Therefore,
it is the action of the δ -electrons that, together with the primary ionization,
determines the biological action of the ions. Heavier particles are faster thanlighter ones at the same LET, hence they deposit a larger fraction of energy
via fast δ -electrons at a greater distance from the particle trajectory whichleads to that particles of the same LET, but different atomic number, havedifferent RBE. Along the particle tracks, radicals and reactive oxygen species(ROS) are also produced due to radiolysis of water. To understand in details
the track structure around the primary and secondary particles are therefore
essential to be able to determine the biological effects of the particles. This
presentation will describe the basic physical phenomena which occurs whenhigh energetic protons and ions penetrates human tissue and organs, incl.
nuclear reactions, dE/dx, straggling, and the production of δ -electrons. Somemodels and particle and heavy ion transport codes used to describe some ofthese phenomena will also be discussed.
341 speaker
SCOPE OF PRACTICE IN THE NEW CORE CURRICULUM FOR RTS
M. Coffey1
1

TCD D IVISION OF R ADIATION T HERAPY, Radiation Technology, Dublin,
Ireland Republic ofAbstract not received.

W EDNESDAY, M AY 11, 2011
342 speaker
HOW TO CONVERT GOOD MATERIAL INTO A GOOD PAPER IN A
MEDICAL PHYSICS OR CLINICAL JOURNAL
D. I. Thwaites1 2 , S. Webb3
1
I NSTITUTE OF M EDICAL P HYSICS , S CHOOL OF M EDICAL P HYSICS ,U NIVERSITY OF S YDNEY, NSW, Australia
2
U NIVERSITY OF L EEDS, Medical Physics, Leeds, United Kingdom
3
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Department of Medical Physics, Sutton, United Kingdom
Purpose: In this invited talk we give our pooled personal views on whatmakes for a good paper at the publication stage.
Materials: The talk is from the perspective of personal experience over some
30-40 years of publishing in peer-reviewed journals and from acting as reviewers, editors and editorial board members.
Results: Key considerations are: (i) what exactly is the "story" - writers
should be clear what they want to say and what is the key message; (ii) the
introduction should clearly indicate where the research work fits into the theexisting research envelope in the field. The authors should progress rapidly
from generalities to specifics. Even well carried out work presented in a wellwritten paper will not be acceptable in high impact-factor journals if it is not
sufficiently novel and/or significant; (iii) the methods should be written in a
way that someone else could in principle repeat the work. Good diagrams
are helpful. The writers should imagine themselves as readers and be clear
and complete. Acronyms should be explained in full the first time of use. (iv)
results should clearly tie figures and tables to text. Ideally figures and tables
should standalone. (v) the conclusions should relate back to the key message
and each be verifiable by reference to the results. The discussion and conclusions should not just be a re-statement of the results in different wording!
It is good practice to have the ’final’ draft paper read over internally by a colleague who has not been connected with the work and who is not an expert
in that topic and ask for comments on clarity, gaps, etc. If they can’t understand it then neither will the referees! It is often the case that leaving a gap
between starting to draft a paper and finalising it for submission can greatly
help to clarify the possible missing information and further work, ie. when you
read it again yourself. Check the journal requirements for submission format
and comply with it. Hastily prepared submissions are usually poorly preparedsubmissions! Badly written papers, not complying with the journal requirements and for example having mistakes in references, immediately give theimpression that the work has not been thought through properly, given thatthe evidence shows that the paper has not been thought through properly!
Conclusions: Much that can be said about good paper writing is fundamentally obvious. Like all didactic activities it can be learnt by working with a moresenior author (e.g. PhD supervisor) as a start. Another good technique is to
ask this person to annotate a paper they recommend as a good model. A
certain way to see some bad papers is to act as a reviewer! We don’t professto be ideal ’paper-writers’, but we have prepared a lot ourselves and seen
even more as reviewers and editors and believe that new writers can learn
good practice by example.

W EDNESDAY, M AY 11, 2011

Symposium
ESTRO-EAU Joint Symposium: Prostate Cancer What is the evidence-based that is being createdright now? The best of clinical trials
343 speaker
OPTIONS AND OUTCOME OF SALVAGE TREATMENT AFTER
RADIOTHERAPY
G. Ahlgren1
1

S KÅNE U NIVERSITY H OSPITAL, Lund, Sweden

Recommendations in the updated EAU guidelines from April 2010 on salvage
treatment after radiotherapy are;Local recurrences may be treated by salvage radical prostatectomy in carefully selected patients, who presumably demonstrate organ-confined disease,i.e. PSA < 10 ng/ml, PSA-DT > 12 months, low-dose-radiation brachytherapy,
biopsy Gleason score < 7 Grade B
Cryosurgical ablation of the prostate and interstitial brachytherapy are alternative procedures in patients not suitable for surgery Grade B
High-intensity focused ultrasound might be an alternative option, however,patients have to be informed about the experimental nature of this treatment
modality due to the short follow-up periods reported.
ADT is an option in patients with presumed systemic relapse Grade B
Local failure after radiation therapy is known to occur in 20-30% in different
series. If there is a PSA failure defined as PSA nadir + 2 ng/ml without signsof metastasis, local failure should be ruled out by performing a transrectal
biopsy before hormonal treatment is started
If a local failure is verified, a C11-choline PET-scan may rule out lymph nodemetastasis and the patient should be offered local salvage treatment.
The options described are radical prostatectomy, brachytherapy, High Intensity Focused Ultrasound (HIFU), vascular targeted photodynamic therapy(VTP) and cryotherapy. No randomized trials on local salvage treatment areavailable and the data presented are institutional reports.
Radical prostatectomy is recommended in patients with clinically localized
disease, PSA<10 ng/ml and a Gleasonscore ≤7. Other predicitve factors ofa high success rate are also PSADT >12 months, brachytherapy failure and<50% cancer in biopsies. The success rates depend upon patient selection,
but are regularly reported to be approximately 50% Alternative treatments are cryotherapy and brachytherapy. The successrate is higher in patients that has not received hormonal therapy and with a
PSA < 10 ng/ml at salvage treatment. The lower the PSA nadir post salvage
treatment, the higher the success rate.
In a recent series of brachytherapy only 38% biochemical relapse free (BCR)
survival was reported and radiation resistant prostate cancer should perhaps
not be treated with more radiation. Data on cryotherapy from the cold registerby Pister et al 2008 shows a BCR-free survival of 60% at 5 years.
Complication rates include incontinence and impotence as well as rectourethral fistula after all types of local salvage treatment.
Systemic failure after radiation therapy (RT) for prostate cancer may betreated with early or late Hormonal treatment (HT). In the control arm notreceiving HT with RT in a randomized trial RTOG 85-31, overall survival weresignificant longer in the early HT group (PSA < 10 ng/ml) compared to thosereceiving late HT. Many studies have shown a significant prolonged time tometastasis with early HT, but survival benefit is limited.
Ongoing trials are testing HT in combination with docetaxel at the time of rising PSA. A new generation androgen receptor blockers like MDV3100 is also
challenging conventional HT in patients with rising PSA after treatment withcurative intention.
344 speaker
WILL OUR GUIDELINES BE RESHAPED BY: ROBOTIC SURGERY?
V. Ficarra1 , M. Mancini1 , M. Iafrate1 , F. Dal Moro1 , G. Novara1
1
U NIVERSITY OF PADUA, Department of Oncologic and Surgical Sciences,
Urologic Unit, Padua, Italy
According to the most important international guidelines (EAU and NCCN)
radical prostatectomy (RP) is considered the gold standard for surgical treatment of patients with clinically-localized prostate cancer (PCa) and a life
expectancy >10 yr. Best candidates for radical prostatectomy are patientsgrouped in low or intermediate risk groups following the D’Amico risk stratification. Selected patients with high risk prostate cancer can be consideredgood candidate for RP and extended lymphadenectomy. Active surveillancein patients with low risk disease, and external radiation therapy, with or without androgen deprivation, in intermediate and high risk groups represent atpresent the best therapeutic alternative. RP with extended lymphadenectomy can be considered also in selected very high risk patients. Retropubic
radical prostatectomy (RRP) is still considered the gold standard for surgical treatment of localized prostate cancer. However, in the last decade, increased interest has been shown for laparoscopic techniques, both in Europe
and United States. The acceptance of traditional laparoscopic RP (LRP) has

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been limited primarily by the steep learning curve; in contrast, robot-assisted
laparoscopic prostatectomy (RALP) has spread rapidly around the world. Today, in the United States, more than 80% of RP are performed robotically, anda similar trend has been observed in Europe. Peri-operative, functional andoncologic aspects are the most relevant outcomes after RP.
Available comparative studies show that LRP and RALP have significantly
lower blood loss and transfusion rates as compared to RRP. In addition, mostof the studies showed similar overall complication rates. Twelve-month urinary continence rates ranged from 66 to 93% after RRP and from 67 to 95%
after LRP. Reported 12-mo urinary continence rates after RALP are 8497%.
So far, studies comparing RRP and LRP have shown overlapping results interms of urinary continence recovery. RALP seems to be associated withan earlier continence recovery, with overlapping 12-mo urinary continence
rates. In patients who underwent nerve-sparing RP, the 12-month potency
rates after RRP ranged from 40 to 73%. This results seem to improve with alonger follow-up, reaching percentages variable between 63 to 86%. The 12mo potency rates after LRP and RALP ranged from 46 to 82% and from 70
to 80%, respectively. Unpublished cumulative analysis of studies comparing
RRP and RALP seem to show a significant advantage of RALP in terms ofpotency recovery. Patients who underwent RRP showed an overall positive
surgical margins (PSM) rate ranging from 12 to 37%, according to different
pathological stage. In LRP patients, these percentages ranged from 4.7% to21%, in pathologic organ-confined tumors, and from 17% to 54%, in pathologic locally-advanced tumors. Looking at the largest RALP series, the overall
PSM rates ranged from 9% to 29%. Specifically, PSM rates were from 1.5%
to 18% in pathologic organ-confined disease and from 19% to 57% in locallyadvanced disease. Cumulative analysis of all available studies comparing
RRP and RALP showed a statistically significant difference in favor of RALPin terms of PSM. More recent RRP series showed a 5 and 10-yr biochemicaldisease-free survival ranging between 70-92% and 68-85% of cases, respectively. Looking at cancer-specific survival, the 5 and 10-yrs survival estimates
after RRP were 99% and 95-99%, respectively. Few data were available concerning bDFS after LRP and RALP. Recently, Menon et al. published theoncological results of 1384 patients submitted to RALP between 2001 and2005, with a median follow-up of 5 years (IQR 37.2-69.7 months). The actuarial BCR-free estimates at 3, 5, and 7 yr were 90.6%, 86.6%, and 81.0%
respectively.
RP remains an effective treatment for localized prostate cancer, with excellent
long-term oncological outcomes. Currently, results of RALP series analysis
don’t seem to be mature enough for a definitive strict oncologic evaluation.
However, RALP provides a less invasive approach, with apparently similar
oncologic outcomes and probably slightly better functional outcomes (especially in terms of potency recovery).
According to this data, it is our opinion that the next international guidelines
should consider to include RALP as a suitable alternative to open surgery, in
prostate cancer surgical treatment.
References
Ficarra V, Novara G, Artibani W,et al. Retropubic, laparoscopic, and robotassisted radical prostatectomy: a systematic review and cumulative analysis
of comparative studies. Eur Urol. 2009; 55(5):1037
Murphy DG, Bjartell A, Ficarra V, Graefen M, Haese A, Montironi R, Montorsi
F, Moul JW, Novara G, Sauter G, Sulser T, van der Poel H. Downsides of
Robot-assisted Laparoscopic Radical Prostatectomy: Limitations and Complications. Eur Urol. 2010; 57: 735-746
Menon M, Bhandari M, Gupta N, Lane Z, Peabody JO et al Biochemical Recurrence Following Robot-Assisted Radical Prostatectomy: Analysis of 1384
Patients with a Median 5-year Follow-up Eur Urol 5 8 ( 2 0 1 0 ) 8 3 8 8 4 6345 speaker
WILL OUR GUIDELINES BE RESHAPED BY: PARTICLE BEAMS?
A. Zietman1
1
M ASSACHUSETTS G ENERAL H OSPITAL, Radiation Oncology, Boston, MA,USA
12 years ago the question could have been will our guidelines be shaped by
IMRT. Most would have said no and been wrong. IMRT has proved a safer
way to deliver higher radiation doses and higher doses are associated with ahigher chance for cure as proven in multiple RCTs. IMRT, though expensive,
is not orders of magnitude more expensive than the least costly alternative.
There may also be lower morbidity from IMRT but this is more difficult toprove. Particle beams will be widely accepted if they are:
1. if they are able to prove further dose escalation is safe and further increases cure. Current evidence suggests that we may be approaching adose-limit for the prostate by any means of radiation delivery although partial
prostate boosting may be feasible.
2. if quality of life studies can be performed and show significant benefit relative to other forms of radiation and surgery. The few studies performed todate are not optimistic, perhaps because most of the major morbidity is theconsequence of the high-dose volume rather than the radiation of the more
peripheral tissues to lower doses.
3. If there is the capacity for treating prostate cancer after the priority areasof pediatrics, eye, and spine tumors have had their time. This assumes that
European nations place these more evidence-based endpoints higher on thepriority scale than looser indication such as prostate cancer.

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4. if the cost of delivery can be dramatically reduced. Here there is substantial potential.
5. if the novel technology of real-time PET dosimetry proves a safer way toadjust beams and verify dose delivered. Here there is substantial potential.
6. if overuse does not discredit the technology and provoke a backlash either
by the public, governments, or insurers. In the United States this point may
have already been reached.
I do believe that particle beams will be "game changers" in the field of radiation oncology but may not do so in the world of prostate cancer without
significant proof of value defined as benefit that is worth the cost.
346 speaker
WILL OUR GUIDELINES BE RESHAPED BY: BRACHYTHERAPY?
P. Hoskin1
1
M OUNT V ERNON H OSPITAL, Cancer Centre, Northwood Middlesex, United
Kingdom
Prostate brachytherapy may be given by low dose rate seed permanent
brachytherapy or high dose rate temporary afterloading brachytherapy. Low
dose rate seed brachytherapy is now well established as an important treatment option for patients with low risk prostate cancer. High dose ratebrachytherapy used as a boost with external beam radiotherapy is gaining increasing popularity as a means of dose escalation for intermediate and higher
risk prostate cancer. In future years the role of brachytherapy is likely to expand representing the most conformal means of delivering high dose rate
radiation to the prostate gland.
LDR seed brachytherapy used alone has been largely confined to patientswith early low risk disease as defined in the ESTRO EAU guidelines. There ishowever increasing experience of using LDR seed brachytherapy in patientswith intermediate risk prostate cancer with results equivalent to those of othermodalities and given the favourable toxicity profile its role in this group of patients is likely to expand.
Combined treatment with external beam and brachytherapy represents the
optimal means of dose escalation. The increasing evidence to support a
low alpha beta ratio for prostate cancer strongly supports the use of highdose rate brachytherapy with large doses per fraction in this setting. Thereis one randomised trial providing level I evidence that this is an effectivemeans of dose escalation but using unconventional hypofractionated externalbeam radiotherapy. There is no randomised data to support the use of seedbrachytherapy as a boost after external beam radiotherapy but nonethelessthis has also become common treatment in centres where seed brachytherapy is the preferred method of interstitial treatment. Early data suggests thatsingle dose HDR boosts are effective and further evidence supporting thisview and providing more robust data on toxicity is likely to make this the treatment of choice for combined external beam and brachytherapy schedules.
High dose rate brachytherapy alone has yet to be fully exploited. The
favourable biological characteristics of prostate cancer make high dose
rate brachytherapy using large doses per fraction an attractive proposition.
There is an increasing body of published data of patients treated with HDR
monotherapy successfully for both low risk and intermediate risk cancers. Optimal dose fractionation schedules will be established and based on these it
is to be hoped that randomised trials will ensue to establish the relative rolesof HDR brachytherapy and LDR brachytherapy alone in the management ofearly and intermediate risk prostate cancer together with their relative toxicity
profiles.
Brachytherapy is also a potential means of enabling retreatment for local relapse after external treatment. Both LDR and HDR techniques have beenreported and with increasing experience this is likely to be a further option forrelapsing patients seeking local salvage.
In summary brachytherapy will remain an important treatment modality forprostate cancer both alone for low and intermediate risk disease and in combination with external beam schedules for intermediate and high risk disease.
New indications will include LDR brachytherapy for intermediate risk disease,
HDR monotherapy for low and intermediate risk disease and both LDR andHDR techniques for salvage after local relapse.

Normal tissue - What is the evidence-base that isbeing created right now? The best of needed clinical trials
347 speaker
INTRODUCTION: WHAT IS THE EVIDENCE BEING CREATED NOW?
F. Stewart1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Experimental Therapy, Amsterdam, Netherlands

1

As cancer treatments become more successful, there are increasing numbersof long-term cancer survivors. Unfortunately, many of these cancer survivors
are at risk for development of treatment related side effects. UnderstandingW EDNESDAY, M AY 11, 2011
the mechanisms of development of damage in irradiated tissue is fundamental to attempts to limit or prevent these side effects. This talk will introduce
some of the approaches for inhibition of radiation injury that have been developed in pre-clinical models and discuss how they are being, or could be,applied in the clinic.
Strategies for reducing the severity of acute radiation injury are aimed at either preventing initial cell death or stimulating proliferative recovery. It is obviously crucial that these effects are limited to normal tissues and do not occur
in tumours. Induction of free radicals occurs rapidly after ionizing radiation
and radical scavengers are potent radiation protectors. Amifostine is among
the most effective of this class of drug and it has been widely studied asa clinical radioprotector, particularly to reduce xerostomia in head and neckcancer patients. Protection against radiation-induced pneumonitis has also
been reported some clinical trials. Transient inhibition of apoptosis (by inhibition of p53 in epithelial or lymphoid stem cells) gives effective protection
against acute bone marrow and intestinal injury after whole body irradiation of
mice. Some experimental studies also show that inhibition of early radiationinduced apoptosis in endothelial cells (through a p53-independent inhibitionof ceramide production) can protect against acute small bowel and lung radiation toxicity. The efficacy of these approaches for protection in the clinic
remains to be tested.
Haematopoietic growth factors have been used for many years to stimulate
recovery of the bone marrow and this approach is now being extended toother growth factors. KGF-1 (palifermin) gives substantial protection against
acute radiation-induced oral mucositis, intestinal damage and pneumonitis in
pre-clinical studies. Palifermin has now been successfully tested in patients
receiving total body irradiation and chemotherapy prior to bone marrow transplantation. Some promising results are also reported for patients undergoingpost-operative radiotherapy for head and neck cancer.
Vascular damage and fibrosis are major underlying causes of late radiation injury. Inflammatory and coagulation cascades are initiated in irradiatedvessels, which lead to vascular leakage, micro-thrombus formation and secondary tissue ischaemia. Over-production of TGFβ and thrombin also drivesmooth muscle cell proliferation and collagen production in fibroblasts, initiating the development of fibrosis. Various intervention therapies aimed atblocking TGF signalling have proved effective in reducing the developmentof fibrosis in lung and intestine in animal models. Anti-platelet agents inhibit microvascular damage and late radiation induced injury in some animalmodels. In addition to their lipid lowering properties, statins are potent antiinflammatory and anti-thrombotic agents that also inhibit Rho/Rock signallingand production of fibrogenic CTGF. Experimental studies show that statins inhibit macrophage recruitment to irradiated lung, reduce fibrosis and increaseanimal survival. Statins also reduce radiation enteropathy in animal models,and one clinical study demonstrated reduced rectal toxicity after pelvic irradiation in combination with statins.
Radiation induced damage is associated with prolonged oxidative stress. Superoxide dismutase (SOD) decreases oxidative stress and confers protection against radiation induced pneumonitis in experimental models. Cu/Zn
SOD has also been successfully used to treat established radiation fibrosis inboth animal models and in clinical trials. Pentoxifylline and vitamin E, whichhave both anti-inflammatory and anti-oxidative properties, also significantly
reduced lung toxicity and skin fibrosis in clinical trials of irradiated breast orlung cancer patients.
The renin angiotensin system (RAS) plays a key role in regulation of haemodynamics in the kidney, lung and circulatory system. Angiotensin II (AII) also
upregulates TGF and may thereby contribute to fibrosis. Preclinical studies
show that ACE inhibitors and AII receptor antagonists inhibit development andprogression of radiation nephropathy, lung and brain damage. A clinical trial
has now also demonstrated improved renal function and increased survival inpatients who received captopril after TBI with bone marrow transplant.
348 speaker
LATE REACTIONS: WHICH MOLECULAR PATHWAYS ARE INVOLVED
M. C. Vozenin-Brotons1
1
I NSTITUT G USTAVE R OUSSY, Biology, Villejuif, France
Fibrosis is one of the main pathological hallmarks associated with late reactions induced by radiation therapy. Characterized by abnormal remodellingof extracellular matrix, radiation-induced fibrosis is triggered by activation of
local fibroblasts and circulating fibrocytes into activated myofibroblasts. During the past 20 years, the signals involved in these activation processes havebeen extensively studied. Today, several fibrogenic factors have been identified along with their downstream intracellular signalling pathways.
Among these factors, transforming growth factor beta 1 (TGFb1) is the best
described. The immediate source of activated TGFb1 is extracellular, as it
is stored in a latent form (LTGFb1) bound to the matrix. Active TGFb1 is released from LTGFb1 by the actions of proteases (plasmin and thrombin) andreactive oxygen species (ionising radiation). Active TGFb1 binds and activates specific plasma membrane receptors (types I and II serine/threonine
kinases) that signal via the canonical Smad pathway, in which Smad proteinsact as signalling molecules, transcription factors and co-factors for procollagen and other matrix target genes. Alternative signalling routes from the
TGFb1 receptor (TGFb1R) complex in the plasma membrane to the nucleus

W EDNESDAY, M AY 11, 2011
bypass cytoplasmic Smad proteins, using the so-called p38, JNK, ras/ERK
MAP kinase and Rho/rho kinase (ROCK) pathways.
TGFb1 is not the only fibrogenic cytokine capable of activating myofibroblasts, in addition to TGFb1 the products of Thy-2 lymphocytes can be mentioned including IL-4 and IL-13. Amongst the growth factors basic fibroblast
growth factor (bFGF), platelet derived growth factor (PDGF), insulin growth
factor (IGF), several chemokines, endothelin-1 (ET-1) and connective tissue
growth factor (CTGF) form a longer list of potent fibrogenic factors capableof activating myofibroblasts alone and more importantly in conjunction with
TGFb1.
CTGF is a matricellular protein that promotes fibroblast proliferation and ECM
production yet uncharacterized plasma membrane receptors and activatesdownstream fibrogenic signalling cascades.
PDGF represents a family of structurally and functionally related growth factors, including PDGF-A, -B, -C and -D that mainly target mesenchymal cells.
Their physiological and fibrogenic actions are achieved by homodimerisation of the growth factors (creating PDGF-AA, PDGF-BB etc dimers) thatbind to specific plasma membrane receptors (PDGFR-a and PDGFR-betc).
PDGFR-a is transactivated by TGF-b1 and is especially associated with fibrosis. PDGF signals through major transduction pathways including PI3K,
Ras/MAPK and PLCg to stimulate myofibroblast proliferation and extracellular matrix synthesis.
The identification of pathways involved in radiation-induced fibrosis offers abewildering range of therapeutic targets that need to be carefully investigatedand validated to provide safe clinical opportunities to improve the quality oflife of long-term cancer survivors.
349 speaker
VASCULAR MEDIATED NORMAL TISSUE DAMAGE AND STRATEGIES FOR INHIBITION OF THIS PROCESS
M. Hauer-Jensen1
1
U NIVERSITY OF A RKANSAS FOR M EDICAL S CIENCES, Biology, Little Rock,USA
The risk of injury to normal tissues continues to limit the cancer cure rates
that can be achieved with radiation therapy. While killing of target cells is
primarily responsible for the initial injury after exposure to radiation, damage to the microvascular endothelium exerts a substantial influence of bothacute and chronic toxicity in many normal tissues. In the past, strategies
aimed at preventing or mitigating the microvascular aspects of normal tissue
radiation toxicity have consisted mainly of various types of anticoagulants or
antiplatelet agents. More recent insight into the crosstalk between the coagulation system and the inflammatory system; into the mechanisms that underlie thrombin’s cellular, receptor-mediated properties; and increased knowledge about the molecular basis by which endothelial cell injury interacts withother cell types provide opportunities for endothelial-oriented interventions
that ameliorate tissue injury with little or no effect on blood clotting. Examples
of such interventions include preservation or restoration of the thrombomodulin/protein C system, blockade of cellular thrombin receptors, or strategies
to prevent uncoupling of endothelial nitric oxide synthase. This lecture provides an overview of the mechanisms by which radiation causes endothelial
dysfunction and briefly discusses how novel vasculoprotective interventions
may ameliorate radiation-induced oxidative and nitrosative stress, endothelial
dysfunction, and tissue injury.
350 speaker

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Symposium
Brachytherapy - dosimetry and dose calculation
351 speaker
IMAGE BASED POST DOSIMETRY AS A PART OF ADVANCEDQA PROCEDURES AFTER SEEDS IMPLANTATION IN PROSTATE
BRACHYTHERAPY
G. Zwierzchowski12 , B. Blasiak1 , J. Skowronek3
1
G REATER P OLAND C ANCER C ENTRE, Medical Physics Department,
Poznan, Poland
2
P OZNAN U NIVERSITY OF M EDICAL S CIENCES, Electroradiology, Poznan,
Poland3
G REATER P OLAND C ANCER C ENTRE, Brachytherapy, Poznan, Poland
Purpose: The quality of life after treatment, good clinical results andshort, one-time hospitalization are recognized as advantages of low-dose
rate prostate brachytherapy. It’s also established that CT/MR-based postdosimetry is the mandatory procedure after implantation. The aim of thisstudy was to compare the dose distributions for real-time intraoperative USbased dosimetry and post-implant CT-based dosimetry and use this procedure as advanced QA routine after seeds implantation.
Material and methods: Real-time intraoperative procedure was performed
under general anaesthesia. The treatment plan containing information about
seeds positions and dose distribution parameters for prostate and critical organs (urethra, rectum) was prepared, and then I-125 seeds were introduced
into the prostate gland. The dose distribution for 50 patients implanted withlinked I-125 seeds were analyzed. The study was based on two groups ofpatients: with CT scans one day after implantation (33 patients) and with CT
scans after one day and one month (17 patients). Sets of CT images wereprepared to evaluate the positions of the seeds, and prepare post-plans toevaluate the dose distribution. For both imaging modalities (TRUS and CT
images) the dosimetry parameters for prostate (D90, D0.1ccm, V100, V150,
V200), urethra and rectum (D10, D0.1ccm) were recalculated for each patient.
Results: US and CT based analysis showed differences for D10, D90,
D0.1cm, V100, V150 and V200. For prostate the difference was 4% to 40%,
1% to 17% for D90 and D0.1cm and 7% to 32%, 2% to 36% and 4% to 42%
for V100, V150 and V200, respectively. For urethra the difference was 5% to40%, 4% to 60% for D10 and D0.1cm, respectively. For rectum the difference
was 25% to 70%, 1% to 57% for D10 and D0.1cm, respectively.
Conclusions: Statistically significant differences were observed between
dose distribution parameters for real-time intraoperative US-based dosimetry
and post-implant CT-based dosimetry. Observed differences for the prostate
gland and critical organs are results of different patient positioning during thereal-time procedure and CT acquisition. For the CT post-dosimetry high dosearea parameters for the prostate (V150, V200) were more conservative. The
doses for the urethra were higher and the doses for the rectum were lower
than for US-based dosimetry. The seeds migration was not observed. Image based post-dosimetry should be mandatory procedure of QA after seeds
implantation.
352 speaker
COMPARISONS OF CONVENTIONAL AND CONTEMPORARY
TREATMENT PLANNING SYSTEMS IN BRACHYTHERAPY
P. Papagiannis1
1

OXIDATIVE STRESS IN RADIATION-INDUCED NORMAL TISSUEDAMAGE AND STRATEGIES FOR INHIBITION OF THIS PROCESS
J. Williams
Abstract not received.

M EDICAL S CHOOL , U NIVERSITY OF ATHENS, Department of Medical
Physics, Athens, Greece
Besides its socioeconomic advantages and its inherent ability to achieve optimum delivery of conformal radiation dose distributions, brachytherapy lagged
behind external beam radiation therapy in the evolution of dose calculation
algorithms employed in treatment planning systems.
Patient dose calculations in conventional brachytherapy treatment planningsystems rely on the superposition of the same dose matrix for each source /source position. This matrix is pre-calculated according to the American Association of Physicists in Medicine TG-43 formalism, in homogeneous waterof given geometry and dimensions.
Patient imaging is used to delineate patient structures for dose prescription
and reporting purposes. However, the exact dimensions of the bounded patient geometry, the inherently inhomogeneous nature of patient anatomy andinhomogeneities introduced by catheters often used in brachytherapy, arecompletely disregarded in dose calculations. Hence the information available
through patient imaging, an integral part of modern brachytherapy for many
years now, is not fully exploited.
This is about to change as a paradigm shift is currently established inbrachytherapy treatment planning. Following many publications delineating
the deficiencies introduced by the approximations of conventional treatment
planning, several methods have been proposed as advanced dose calculation algorithms in brachytherapy treatment planning. These include analytic
methods, convolution/superposition algorithms, Monte Carlo simulation anddeterministic, grid based Boltzmann solvers. The latter method has been in-S 140S YMPOSIUM

troduced as a standalone option in a commercially available system to provide
individualized patient dosimetry, justifying the use of the term "contemporary
brachytherapy treatment planning".
The aim of this lecture is twofold. First, to critically assess the potential improvements of contemporary over conventional treatment planning as implemented currently. In this regard, the obvious advantage of increased dosimetric accuracy, which has yet to be translated to potential clinical significance,
has to be weighed against simplicity, speed and intra-/inter- clinic consistency. Second, to discuss the need to augment existing commissioning and
QA procedures in order to fulfill the regulatory mandated need for independent dose calculations checks and smooth the uniform transition from conventional to contemporary treatment planning practice. While pertinent societal recommendations are underway, different approaches are beginning toform. Program and spreadsheet methods that perform comparisons at user
selected-reference points are fast and practical. They might lack however the
resolution necessary to delineate differences in 3D image based brachytherapy treatment planning, while the explanation of potential differences mightpresent a formidable problem. A complimentary approach could be the use of
2D/3D methods employing virtual, DICOM-based, phantoms and accompanying reference dose distributions. The problems pertinent to the configuration of such test cases, their realization, and the establishment of acceptancecriteria are also discussed.
353 speaker
NEW DEVELOPMENTS WITH MONTE CARLO CALCULATIONS FOR
BRACHYTHERAPY
M. Rivard1
1
TUFTS-N EW E NGLAND M EDICAL C ENTER, Medical Physics, Boston MA,
USA
Monte Carlo (MC) simulations of radiation transport are the accepted reference method for estimating dosimetric properties of brachytherapy sources.
Given 100 years of clinical use and medical physics activities for characterization and quality assurance, there is good agreement (often within a few
percent) between results of measured and MC-simulated dose rate distributions. While a reality check based on measured results is important due tothe susceptibility of MC methods to gross and fine user-errors and assumptions, MC methods have greater flexibility to simulate a variety of physicalenvironments given their computational nature. This is highlighted by thenearly infinitesimal spatial resolution and high spatial range capable using
this method. Further, unphysical environments and complex temporal effects
may be examined sometimes in a discretized manner. For example, dosimetric contributions from individual photon energies emitted by a polyenergetic
source may be assessed. This concept can be extended to account for evaluating the total dose distribution based on summation of dose distributions
from individual dwell positions. Consequently, the field moves towards MCbased dose calculations for use in clinical treatment planning systems. Here,
substantial improvements are possible over current dose calculation methods
based n the TG-43 approach using superposition of single-source dose rate
distributions in homogeneous liquid water spheres. Scatter conditions andpatient material heterogeneities are currently ignored in clinical practice. MC
methods for evaluating single-source dose distributions and for use in treatment planning will surely advance the field of brachytherapy. Practical approaches are discussed towards building off current paradigms for estimating
clinical dose distributions with MC methods. Coordination of these activities
within the framework of societal recommendations and efforts towards cohesive clinical practice are promoted.

W EDNESDAY, M AY 11, 2011and metal stabilizing structures) CT data can be significantly corrupted due
to problems with the reconstruction algorithms around such structures. Second, there is the problem of converting from CT Hounsfield numbers to proton
stopping powers, as required for accurate proton range calculations. Due tothe non-uniqueness of this relationship, there are inevitably uncertainties resulting from this conversion. Third, over the course of fractionated treatment,
or even between the time of the planning CT and the first treatment day, significant changes in patient geometry can occur that can significantly effectproton range in-vivo. All these uncertainties are problematic as, for the mostpart, they are almost certainly systematic in nature. That is, a range error resulting from inaccurate CT data will be potentially the same every fraction of
the treatment, making such errors particularly worrisome. A final, and related
issue, is the uncertainty in the RBE value in the proton Bragg peak. Although
this can lead to some increased (biological) doses at the Bragg peak, it could
also potentially lead to a ’shifting’ of the distal fall-off of the Bragg peak toslightly deeper depths. As such, RBE uncertainty can also be considered tocontribute to the overall uncertainty of range in-vivo. So is there a risk to using proton therapy from the point of view of range and RBE? Not necessarily
if the issues are understood and are taken into account when designing andevaluating proton treatments. Indeed, although it is still not standard practice
to completely spare a critical structure by the use of the distal fall-off alone,
the fact that protons do stop in the patient (if only with a predictable accuracyof a few percent), still brings significant advantages in normal tissue dose
reduction and also in the complexity of treatment that can be delivered. In
short, the advantage of protons is that they stop, and the disadvantage of notknowing exactly where can be dealt with through knowledgeable and careful
treatment techniques.
355 speaker
PROSPECTS AND CHALLENGES OF IN-VIVO RANGE VERIFICATION IN PROTON THERAPY
A. Knopf1
1

PAUL S CHERRER I NSTITUTE (PSI), Department of Medical Physics,
Villingen, Switzerland
Radiotherapy with protons has the potential of delivering highly conformal
doses to the tumor whilst sparing the surrounding tissues. However, due tothe steep distal dose gradient, uncertainties in treatment planning and delivery can have a profound impact on the actual applied dose. To take full advantage of the superior characteristics of proton beams, tools to monitor andcontrol these uncertainties are needed. The use of on-line/off-line positronemission tomography/computed tomography (PET/CT) scans during or after
proton beam delivery as a quality assurance tool is currently under investigation at a number of proton therapy facilities.
In this talk we want to address the following questions: Is a mm-accurate
treatment verification feasible with off-line activity measurements at commercially available PET/CT scanners? Which tumor sites can most benefit
from off-line PET/CT scans? Which factors compromise off-line activity measurements? Which improvements of the PET/CT verification approach areneeded for other tumor sites? Which accuracy can be expected from on-line
activity measurements? Which alternatives to PET/CT imaging exist for invivo range verification in proton therapy?
References:
1. Gensheimer MF, Yock TI, Liebsch NJ, Sharp GC, Paganetti H, Madan
N, Grant PE, Bortfeld T. "In vivo proton beam range verification
using spine MRI changes." Int J Radiat Oncol Biol Phys. 2010 Sep
1;78(1):268-75. Epub 2010 May 17.

354 speaker

2. Knopf AC, Parodi K, Paganetti H, Bortfeld T, Daartz J, Engelsman
M, Liebsch N, Shih H. "Accuracy of Proton Beam Range Verification
Using Post-Treatment Positron Emission Tomography/Computed
Tomography as Function of Treatment Site." Int J Radiat Oncol Biol
Phys. 2010 Jun 18.

ARE THERE RISKS ASSOCIATED WITH PROTON THERAPY? RANGE DOSIMETRY AND RBE
A. Lomax1
1
PAUL S CHERRER I NSTITUTE (PSI), Center of Proton Therapy, Villingen,
Switzerland

3. Knopf A, Parodi K, Bortfeld T, Shih HA, Paganetti H. "Systematic
analysis of biological and physical limitations of proton beam range
verification with offline PET/CT scans.", Phys Med Biol. 2009 Jul
21;54(14):4477-95.

Risk assessment and dosimetry in proton and ion
therapy

Proton therapy is a rapidly expanding area, with many new facilities currently
in operation, or in the commissioning or planning phase. The reason for thiscurrent boom is clear the well defined range of the proton Bragg peak. However, as has been stated before, although the advantage of protons is thatthey stop, the disadvantage of protons is that we don’t always know where.
So what are the reasons for this uncertainty, and what are the consequences?
Although in water we can measure the Bragg peak range extremely accurately and precisely, there are a number of inherent uncertainties with thesame calculations in the patient. First there is the imperfection of the CT data
used for such calculations, such as beam hardening, noise, partial volume effects etc. In addition, in the presence of high density implants (such as fillings

4. Knopf A, Parodi K, Paganetti H, Cascio E, Bonab A, Bortfeld T. "Quantitative assessment of the physical potential of proton beam range
verification with PET/CT." Phys Med Biol. 2008 Aug 7;53(15):4137-51.
5. Mumot M, Algranati C, Hartmann M, Schippers JM, Hug E, Lomax
AJ. "Proton range verification using a range probe: definition of concept and initial analysis." Phys Med Biol. 2010 Aug 21;55(16):4771-82.
6. Testa M, Bajard M, Chevallier M, Dauvergne D, Freud N, Henriquet
P, Karkar S, Le Foulher F, Lng JM, Plescak R, Ray C, Richard MH,

W EDNESDAY, M AY 11, 2011
Schardt D, Testa E. "Real-time monitoring of the Bragg-peak positionin ion therapy by means of single photon detection." Radiat Environ
Biophys. 2010 Aug;49(3):337-43.

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covered, while the actual criteria of good practice are discussed on genericlevels only. The borderline between clinical audit and other quality assessments (accreditations, certifications, peer reviews) and regulatory inspections
is also discussed.
Ideally the clinical audit should cover the structure, process and outcome of
RADIOLOGICAL practice. The priorities of clinical audit for radiotherapy isshown in the Table.

ABSOLUTE AND RELATIVE DOSIMETRY FOR PROTONS AND IONS- CHALLENGES AND SOLUTIONS
H. Palmans1
1
N ATIONAL P HYSICAL L ABORATORY, Teddington, United Kingdom
Proton and ion beams are increasingly used in radiotherapy because of theiradvantages over photon beams such as the finite penetration depth, theBragg peak near the end of the range, the lower number of beams needed
for high conformality and the lower integral dose delivered to surrounding tissues. Accuracy requirements in dosimetry of these beams are similar as forphoton beams to exploit them to their full potential.
Several groups are trying to establish primary standards for protons andions based on calorimeters. However, the workhorses for routine reference
dosimetry in a clinical environment remain ionisation chambers while someother detectors like alanine, diodes, diamonds, scintillators and radiochromic
film have been reasonably well characterised for relative dosimetry. Many
problems of dosimetry for passively scattered beams have been solved to an
acceptable level in recent years, but the increased usage of scanned particle
beams has raised a whole new range of dosimetric problems.
For passively scattered beams, questions remain concerning the chemicalheat defect in water calorimeters and the derivation of dose to graphite todose to water in graphite calorimeters. For the latter, fluence correction factors are needed due to different total nuclear interaction cross sections andproduction cross sections in water and graphite. For ion chambers, new evidence has emerged that wall and central electrode perturbations are notnegligible and the values and accuracy of stopping power ratios are still under debate. For other detectors like alanine and radiochromic film, the energy
dependence of the dose response has been studied in detail recently.
For scanned particle beams, heat conduction phenomena in calorimeterspose a potential problem. Water calorimeters have the advantage that thethermal diffusivity is low while the advantage of graphite calorimeters is thatthey can be operated in isothermal mode. In ionisation chambers an issue
concerning scanned beams is the potentially high recombination effect due
to the high instantaneous dose rates that it will experience while the spot
sweeps over or hits the chamber and also due to the inhomogeneity and timedependence of dose profiles. Another aspect that needs further investigation
is if perturbations due to the instantaneous inhomogeneity are compensatedwhen a large field is built up from small beamlets. For relative dosimetry themain problem is that point dosimeters are not suitable in scanned beams andion chamber, diodes arrays, gels, scintillating screens and liquids, etc. are
introduced, many of which have not been sufficiently characterised for proton
and ion beam dosimetry.
The above mentioned problems and proposed solutions will be reviewed withparticular attention for dosimetric issues that are the result of moving frompassively scattered beams to actively scanned beams.

Clinical audits in radiotherapy - Joint with Physics
357 speaker
EUROPEAN GUIDELINES - 2009 RECOMMENDATION BY EUROPEAN COMMISSION
H. Järvinen1
1
R AD. AND N UCLEAR S AFETY AUTHORITY (STUK), Helsinki, Finland
Purpose/Objective: The Council Directive 97/43/EURATOM [1] introduced
the concept of clinical audit to medical RADIOLOGICAL (diagnostic radiology,
nuclear medicine and radiotherapy) procedures. Clinical audit is a systematic
review of the procedures in order to improve the quality and the outcome ofpatient care. According to the directive, clinical audits shall be implemented
in accordance with national procedures. The review of its implementationin Europe has revealed a high variation of approaches and many practicalproblems. Therefore, the European Commission has undertaken a project toprepare further guidelines on clinical audits. The purpose is to improve theimplementation of clinical audits and to enable the Member States to adopt
the model of clinical audit with respect to their national legislation and administrative provisions.
Material/Methods: Within a two year project (2007-2008) funded by the European Commission, further guidelines on Clinical audit has been preparedand published by the EC in its report Radiation Protection No 159 (2009) [2].
Results: The European guidelines address clinical audits in all fields of applications (diagnostic radiology, nuclear medicine and radiotherapy). They
point out the importance of both internal and external assessments for clinical audit. The report deals with all types and levels of clinical audit and gives
practical guidance for application. It defines the list of topics which should be

The European guidelines address all professional groups, hospital management, auditing organizations and regulatory bodies. It is important to recognize that the report is not a legal requirement. It is flexible by nature and canbe supplemented by other guidelines of clinical audit such as the guidelines
for comprehensive clinical audits in radiotherapy (QUATRO [3]), published by
the IAEA.
Conclusions: The clinical audit is a multi-disciplinary, multi-professional asseessment for the improvement of the safety and quality of the practices. The
European guidelines (Radiation Protection 159) provides a general framework to establish a sustainable national system. The EC guidelines can besupplemented by other guidelines on clinical audit, such as thouse publishedby the IAEA (QUATRO).
References:
1. EUROPEAN COMMISSION. Council Directive 97/43/Euratom of 30
June 1997, on health protection of individuals against the dangers ofionizing radiation in relation to medical exposure, and repealing Directive 84/466/Euratom. Official Journal of the European Communities
No L 180/22-27, 9.7.1997.
2. EUROPEAN COMMISSION. "European Commission Guidelines on Clinical Audit for Medical Radiological Practices(Diagnostic Radiology,
Nuclear medicine and Radiotherapy)", Radiation Protection No 159, 2009, available fromhttp://ec.europa.eu/energy/nuclear/radiation_protection/publications_en.htm
3. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA). Comprehensive Audits of Radiotherapy Practices: A Tool for Quality Improvement.
Quality Assurance Team for Radiation Oncology (QUATRO). IAEA, Vienna 2007.

358 speaker
CLINICAL COMPREHENSIVE AUDITS - AN IAEA PROJECT AND
CURRENT DEVELOPMENT
M. Coffey
Abstract not received.

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W EDNESDAY, M AY 11, 2011359 speakerjob, or work in countries where it is possible to be trained in the post. Certainly it is always very helpful to have an international PhD to apply for thevarious options and take the decision.
In conclusion an international PhD is an excellent way of starting to work in
medical physics, but bearing in mind that to work in an hospital environment
after finishing it, in most cases it is still necessary to undergo a clinical training.

IMPLEMENTATION OF CLINICAL AUDITS IN RADIOTHERAPY IN
POLAND IN THE LIGHT OF NEW EC RECOMMENDATION
M. Bogusz-Czerniewicz1
1

G REAT P OLAND C ANCER C ENTRE, Poznan, Poland

Background: In 2006, following a call for tenders on the basis of advice
from the Working Party on Medical Exposure under the Article 31 Group ofExperts, the European Commission decided to award a contract to develop
European guidance on implementation of clinical audit of medical radiologicalprocedures. In 2008 the Guidelines on Clinical Audit for Medical Radiological
Practices were drafted under contract and subsequently discussed with various stakeholders. As a result in 2009 European Commission published Radiation Protection No 159 European Commission Guidelines on Clinical Audit
for Medical Radiological Practice (diagnostics imaging, nuclear medicine andradiotherapy Directorate-General for Energy and Transport Directorate H Nuclear Energy Unit H.4 Radiation Protection 2009". The main purpose of theseEC guidelines was to a/ provide guidance on clinical audit in order to improve
implementation of Article 6.4 of Council Directive 97/43/ EURATOM (European Commission, 1997, b/ increase awareness of staff involved in the process of auditing and c/to provide comprehensive information on procedures
and criteria for Clinical audit in radiological practices: diagnostic radiology,
nuclear medicine and radiotherapy. The Regulation of the Polish Ministry of
Health on safe use of ionizing radiation for medical purposes passed on August 25, 2005 and amended in 18 February 2011 obliges all radiotherapy
units to perform the internal and external clinical audits since 2009.
Aim: The aim of this paper is to present the clinical, internal and external audit model for radiotherapy in Poland elaborated by the author on the requestof the National Centre for Radiation Protection in Health Care and the Ministry of Health.
Materials and Method: The aforementioned EC guidelines together with thecomprehensive audit for radiotherapy practice model proposed by IAEA Quality Assurance Team for Radiation Oncology (QUATRO) were used as a platform for the elaboration of the national clinical audit model, compliant with thenational regulations in Poland.
Results: The model of internal and external clinical audit for radiotherapy
including procedures and the complementary documentation has been elaborated. The detailed procedure has been presented in Figure 1: Externalclinical audit model for radiotherapy in Poland.
Discussion: The National Commission for Standard Procedures and External Clinical Audits for Radiotherapy, appointed by the Polish Ministry of Healthis responsible for the implementation of the proposed model and the conduction of clinical audits in 27 operating radiotherapy facilities in Poland. It isplanned to audit at least 5 institutions annually every five years. The external clinical audits for radiotherapy although mandatory since 2009 will belaunched in May 2011 which is undeniably triggered by the publication of the
EC Guidelines on Clinical Audit for Medical Radiological Practice.

W EDNESDAY, M AY 11, 2011

361 speaker
THE BENEFITS AND CHALLENGES OF HAVING CLINICAL TRAINING FIRST THEN A PHD
P. Carrasco de Fez1
1
H OSPITAL DE LA S ANTA C REU I S ANT PAU, Servei de Radiofísica iRadioprotecció, Barcelona, Spain

PhD in medical physics, and then......? some invivo experiences

PhD is supposed to certify excellence in a subject and the ability to do research in a field. In my opinion, and from a rational point of view, the best
way to manage knowledge about a subject is first knowing perfectly the whole
field you are dealing with and then going deeper into a specific subject, which
would be the PhD thesis. Physicists are not trained in clinical issues during our studies. Having a clinical training first gives you a broader picture of
the field, conveys you the order of magnitude of all parameters and makes
you know what is essential and what is negligible. Knowing perfectly all theequipment and tools for your research in advance makes your research more
efficient; and doing it in a particular subject of real clinical interest makes it
more remarkable and relevant.
After a clinical training, the trainee usually starts working in a hospital environment. Therefore, when the PhD is done after a Clinical Training, theresearcher is usually working at the same time that the research is being
done. Doing a PhD while working is always a challenge, but doing it in Medical Physics is especially difficult. If it is done in a hospital is even more
complicated. Hospitals are intended to treat patients and all the technology
is obviously dedicated to patients. Therefore, to have all the required technology available it is necessary to wait until the normal activity is finished. Other
strategies to manage the situation are possible but they have to be set up
carefully. Medical physics is a quite demanding working field, so in working
hours there is no time for research. Consequently, most of the spare time
while doing a PhD has to be sacrificed.
The main drawback of doing a clinical training first is that sometimes there
researcher would like to have more time for studying, thinking, planning thework and evaluating the results as intensively as one would like to.
Despite all the previous circumstances, the balance is positive and from mypoint of view, the ideal way of doing a PhD in Medical Physics would be having
had a clinical training first.

360 speaker
THE BENEFITS AND CHALLENGES OF AN INTERNATIONAL PHD
FOLLOWED BY WORK IN A HOSPITAL ENVIRONMENT
V. Panettieri1
1
W ILLIAM B UCKLAND R ADIOTHERAPY C ENTRE, Melbourne, Australia
The ways to get to work as a Medical Physicist in a clinical environment arecertainly vary and up to now different countries have had different regulations
to start this career. The most followed route is a clinical training but anothervery valid path is to undertake a PhD in a medical physics related topics, fromany scientific background, and then start working in the clinic.
The advantages of this alternative route are many and, in my opinion, very
enriching. Starting from a PhD provides you with the opportunity to study indepth some aspects of the subject and to have time to understand some of
the theory behind the day-by-day routine, which is usually a difficult task in aclinical post where the majority of the time is dedicated to quality assuranceof patients and machines. If the PhD is conducted full-time there is also thepossibility to organise the schedule in order to use the resources, usually notavailable during treatment times, towards research and to explore new technologies and methods freely.
A PhD in medical physics is also an excellent way to get to know a job anda field that in some cases was not included in the previous education, and it
allows you to observe and learn new practices. This is even truer if the research is carried out in different countries, since it is an experience which not
only allows you to learn different ways of dealing with clinical issues but also
to meet many experts in the field and develop a broader and international vision of the profession. Moreover, travelling and working in different countries
is a wonderful personal experience more difficult to have once one is involvedin the clinical routine.
The downside to it is that there is not an easy way then to enter a hospital environment after a PhD. Some countries still require you to undergo acomplete clinical training even if you have been spending many years working in medical physics. This training can be of 3 o 4 years, which add up to
those done during the graduate education. To decide to follow this route canbe quite difficult, and in some cases even not possible since in a number ofcountries regulations might limit the access to the medical physics training
only to students that have obtained a degree in physics. Often the alternative
is to become a post-doctoral researcher which in most cases is a temporary

362 speaker
COMBINING RESEARCH AND CLINICAL WORK WITHOUT A
FORMAL PHD PROGRAMME
C. Garibaldi1
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Medical Physics, Milan, Italy
In Italy there are more than 600 medical physicists, most of them working inRadiotherpy departments. To become a Radiotherapy physicist it is mandatory to undergo the specialization school in Medical Physics which last four
years and provides theoretical and practical training in the fields of radiotherapy, radiology and nuclear medicine. During the specialization school, thephysicist who wants to become a Radiotherapy physicist usually applies fora fellowship in a Radiotherapy department but he/she has also to undergo
practical training in Radiology and Nuclear Medicine departments. During
this four years, the physicist is involved in all aspects of the clinical work without having any responsability under the supervision of experienced physicists
and he/she can also be involved in research activities.
Almost all the italian medical physicists, even those actively involved in research, do not have a PhD in Medical Physics, simply because most of the
Universities in Italy do not provide a PhD programme in Medical Physics.
Moreover, the very few PhD programmes in Medical Physics are rarely related to radiotherapy. So an Italian physicist who wants to apply for a PhD in
the field of radiotherapy has to go abroad.
For physicists who decide to pursue a career in radiotherapy physics andwant to combine clinical and research work, the most important thing to do
is to carefully choose the department. In a large department, especially if
it is wholly or partially university founded, there is more space for research
activities compared to a small department. Most radiotherapy departments
in Italy have low staffing levels so the physicists has to handle, as a priority, the routine aspects of the work required, especially if the department issmall. Moreover, most of the physicists in Italy do work that should be undertaken by radiation technologists. The role of the physicist should be also thatof overseeing the work of radiation technologists, after having trained themand having provided the protocols to follow. This would allow the physicist to
have more time for research and development activities. Even in those departments where research is required, as the one I work in, physicists have

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to perform research beyond the normal work time, in the evenings or weekends. Therefore, most of the time, research activities are carried out thanks
to the willingness of the physicist who wants to combine the clinical work withresearch.
Ideally, the main function of the physicists should be to undertake researchand development with the endpoint that the results of their work should beclinically implemented in order to be of benefit to the patients. In reality, thephysicists, at least in Italy, have to put a lot of efforts trying to do some research beyond the large amount of daily clinical work.
363 speaker
TO PHD OR NOT TO PHD, THAT IS THE QUESTION
C. Clark1 , G. Gagliardi2 , L. P. Muren3
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Medical Physics, Sutton,
United Kingdom
2
K AROLINSKA U NIVERSITY H OSPITAL, Medical Physics, Stockholm, Sweden
3
A ARHUS U NIVERSITY H OSPITAL, Medical Physics, Aarhus C, Denmark
Background: In combining research into your career the question arises as
to whether it necessary or a benefit to undertake a PhD. There are several
approaches as to how to go about this start with a PhD and then continue
with a clinical career or undertake a PhD after having gained clinical experience and whether each should be done full or part time. There is also thequestion of whether training or working in a different country is a benefit. The
Young Scientists committee wanted to ask these questions of a broad rangeof physicists, both young and experienced, to see what the advice would be.
Methods: In order to get input from as many people as possible a questionnaire was designed and sent to all physicists on the ESTRO database.
Questions asked included: Do you have a PhD, did you undertake clinical formal training, at what stage did you do your PhD, is a PhD needed in a career
as a radiotherapy physicist and are there sufficient opportunities to carry out
research whilst working clinically in your country?
Results: 655 answers were received (70.0% from Europe, 3.1% from USA
and 26.9% from other countries). 74.5% undertook formal clinical training.
42.6% had a PhD with 50.8% doing before starting clinical training. 66.9%
felt that having the PhD first benefitted their clinical training. 80.0% of those
who did their PhD after gaining clinical experience said that having clinicalexperience helped with their PhD research. 64.8% did their PhD full time,
whereas 29.6% and 6.4% worked clinically and non-clinically at the sametime as undertaking their PhD studies. 52.2% thought that a PhD is useful for
career advancement, with 38.1% saying it was necessary and 6.9% stating it
was formally required. The majority (55.1%) thought that there were not sufficient opportunities to carry out research part time whilst working clinicallyin their country. 71.4% felt that if more physicists had PhD then the status
and profile of the profession would be raised. Overall a PhD was thought tobe helpful to work in another country in research (92.2%) and in the clinic(66.7%). A more detailed analysis will be given in the presentation.
Conclusions: This survey asked for the opinion of the ESTRO physicists on
the value of undertaking a PhD during a career in radiotherapy physics. The
consensus was that doing a PhD was a beneficial step to take during a careerin radiotherapy physics and that it also benefitted not only individuals, but the
profession as a whole.

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Symposium
ESTRO-EAU Joint symposium: Prostate Cancer Vision for the future: What ‘we’ will ask for in the
new grant applications? - Translational research /High technology
364 speaker
BEYOND STAGE, PSA AND GLEASON SCORE: GENETIC PROGNOSTIC FACTORS
J. Schalken1
1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, 267 Urology,
Nijmegen, Netherlands
Prostate cancer (PrCa) is a major health care problem. Not all criteria aremet for diseases for which population based screening is advised. Yet many
medical organizations have endorsed PrCa screening for the well informed
patient. Currently, PrCa screening is based on the serum PSA test. The
conditional recommendation for screening is due to the main limitations of
the PSA test, i.e. the low specificity and the fact that the test does not discriminate indolent from clinically significant PrCa. High specificity is a priority
requirement for a screening test. Other criteria for PrCa screening tests are, easy obtainable sample, -simple and -cost effectiveness, -ability to discrimate
significant from indolent PrCa and -ability to detect early PrCa. Advancementin biotechnology, such as molecular profiling using microarrays, have given
more opportunities to discover new biomarkers that are better than PSA.
Many steps and a long period of time is needed to identify a novel marker
as an alternative to PSA, and to clinically implement it. Many markers arebeing identified but until now only two markers, PCA3 and ETS gene fusions,are clinically available or close to implementation. These marker are candidates to evaluate in a screening setting. These two biomarkers still needmore validation-, cost effectiveness - and prospective studies. Meanwhile,
there are several ways to increase PSA specificity and sensitivity. Targetinghigh risk population by stratification based on SNPs identified by Genome
Wide Association Studies (GWAS) has been suggested GWAS has found at
least 40 relevant SNPs, but if this can be translated to the entire population
remains to be shown. Recently, gene variants are also found to correlatewith serum PSA levels, so one should anticipate to individualize PSA cut-off
levels. Another gene that was widely studied is BRCA. Men carrying BRCA2
mutations have a high chance to develop aggressive PrCa. There is one
international study to explore PSA based screening effect to this BRCA2 positive population (the IMPACT study). Risk calculators have been developed toincrease PSA specificity and sensitivity since PSA was considered as rangeof risk. Risk calculators were developed based on certain population so theutility of these calculators may be limited to similar patient populations. Nevertheless, risk calculators provide an excellent tool to integrate the effect ofvarious available clinical-, pathological- and molecular parameters.
365 speaker
BEYOND STAGE, PSA AND GLEASON SCORE: WAIT AND SEE
RANDOMISED TRIAL:
A. Widmark1
1
U NIVERSITY U MEÅ N ORRLANDS U NIVERSITETSSJUKHUS, Umeå, Sweden
There is still a great need for further evaluation of the benefit of local curative treatment in prostate cancer. Today active monitoring is also common touse in low risk patients. Regarding surgery, the SPCG-4 trial (Bill-Axelsson)shows 5% increase in overall survival in favour of surgery, after12 years follow
up.
During the late 80’s a group of doctors in Umearted the Ume trial where they
compared deferred treatment versus radiotherapy 64 Gy in similar patients(T1-T2, WHO Grad 1-2) as in the SPCG-4 trial. This trial has now 20 years
follow up of 215 patients, including 40 patients in Denmark and 10 patientsfrom Norway. Presently approximately 75% of the patients have died andan update is ongoing. Fortunately the ProtecT randomized trial in UK, withadequate number of patients, will compare 3 treatments (active monitoring,radical prostatectomy and radical radiotherapy) and evaluate the effectiveness, and acceptability of treatments for men with localized prostate cancer.
In low risk prostate cancer the overall developmental aim of local curative
treatment is to maintain efficacy with reduced toxicity. Examples are implanted markers that facilitates decreased margins and use of more sophisticated imaging (MRI, PET/CT) for doseplaning Decreased toxicity could also
be achieved with new techniques to move risk organs i.e. the rectal wall awayfrom the prostate target. The rectal fixation probe, Turesson et al. and datafrom Prada et al has shown that during brachytherapy, using hyaluronic acidto separate the rectal wall from the prostate will decrease rectal toxicity. To
justify these new techniques, randomize studies on side-effect outcome has
to be evaluated with validated Quality of Life and symptom questionnaires
where the patients are asked about their side effects prior to start of curative
treatment, and than during long follow up (10 years). In Sweden we recently
have started a national project trying to evaluate toxicity prior to start of all

W EDNESDAY, M AY 11, 2011
forms of curative therapy in prostate cancer patients, with follow forms after
at 1 year and 5 years independent of treatment techniques.
In high risk tumours the developmental aim is to improved outcome with combined or more efficient treatments, by performing pivotal studies on doseescalation, HYPO-fractionation, lymphnode treatments and all forms of neoand adjuvant treatments in combination with radiotherapy.
It is well established in many studies that in high risk PC patients hormonal
treatment + radiotherapy (70 Gy) improves outcome in comparison to radiotherapy alone (70 Gy). (Bolla, Granfors, dmico). Today technical developments have occurred with radiotherapy by adding image guided radiotherapy,
intensity modulated radiotherapy and lately VMAT technique treatments. No
randomised studies have evaluated the need for hormonal treatment in highdose ( >78 Gy) treated Intermediate and High-risk PC-patients so there is acontroversy regarding which patients will need additional hormone treatment
with radiotherapy above 78 Gy.Regarding the efficacy of radiotherapy in more
locally advanced PC the SPCG-7 trial published in Lancet 2009 showed thata combination of radiotherapy + hormones is better than hormones alone,
cutting the prostate cancer specific mortality in half, and largely reducing thenumber of patients that progressed.
All the above data are done with radiotherapy 70 Gy, instead of today’s standard 78 Gy with all technical development (IGRT, IMRT, VMAT), or the combination of HDR and external beam radiotherapy suggesting that even higher
doses than 78 Gy could be given. These two techniques should be comparedin randomized trials, to test if > 78 Gy is beneficial with reasonable toxicity,
and also to justify the more expensive technique with EBRT + HDR.
Regarding the future translational research the main focus should be on theissue of which of the men will have a "localized" prostate cancer that later willmetastasise and make the patient dye. This is the overall most important issue in prostate cancer. Most of the studies so far have focused on stage, PSA
and Gleason score evaluated on biopsies or radical prostate ectomy specimens from the primary tumour at diagnosis. Whether these observations in
the primary tumour will predict in whom and how the prostate cancer metastasizes is still a sparsely studied in PC. Future translational studies should probably focus on the interaction between prostate cancer cells and the metastatic
bonetissue, including its stroma. If published results suggesting that 60% of
patients in low risk PC have prostate cancer cells in bonemarrow at diagnosis, the issue on seeding is probably not possible to solve, but bigger focus
should be on new applications to the study of interaction between prostatecancer cells and for example bone metastases.
366 speaker
BEYOND STAGE, PSA AND GLEASON SCORE: BIOLOGICAL AND
FUNCTIONAL IMAGING
J. Barentsz
Abstract not received.

W EDNESDAY, M AY 11, 2011

Symposium
Normal tissue - Vision for the future: What ‘we’
will ask for in the new grant applications? - Translational research / High technology
367 speaker
PREDICTION AND PROGNOSIS OF NORMAL TISSUE RADIATION
INJURY
J. Alsner1
1
A ARHUS U NIVERSITY H OSPITAL, Biology, Aarhus C, Denmark
Presented on behalf of the International Radiogenomics Consortium.
During the last decade, a number of studies have supported the hypothesis that there is an important genetic component to the observed interpatientvariability in normal tissue toxicity after radiotherapy (1). Genetic markers
with sufficient predictive power to be used at an individual level have notbeen identified yet (2). Progress has been made recently, particularly, forpredicting late toxicity. Some of the more promising predictive assays are
based on lymphocytes or fibroblasts. Commonly following in vitro irradiation,
gene expression profiles are measured or functional assays are recorded andused to identify individuals with low or high risk of normal tissue toxicity. Although the technical set-up for these assays makes it unlikely that they willenter any routine clinical settings, they allow the identification of genes thatare involved in the development of radiation induced morbidity. These genes,or the pathways in which they are functioning, could be relevant targets forintervention and might also lead to the identification of candidate genes for
single nucleotide polymorphism (SNP) association studies. So far, most of
the SNP association studies reported have been limited by the inclusion of
low numbers of patients with different kinds of normal tissue toxicity. Future
genetic association studies will be equally impeded by the difficulties in characterising well-defined clinical and biological phenotypes and handling of themany confounding factors.
Recently, an International Radiogenomics Consortium was established (3, 4)
with the primary aim of bringing together researchers interested in indentifying the genetic variants, primarily reported as single nucleotide polymorphisms, associated with the development of radiation toxicity. There are twolong-term goals of this field of research: to develop an assay capable of predicting which cancer patients are most likely to develop radiation injuries following treatment with a standard radiotherapy protocol; to obtain information to assist with the elucidation of the molecular pathways responsible forradiation-induced normal tissue toxicities. The rationale underlying the consortium is that the international scientific community must work together toprovide definitive answers regarding the importance of individual SNPs bycarrying out adequately powered studies which require many thousands ofpatients. The consortium currently has 110 members from North America,
Europe, and Asia. It constitutes a platform for interdisciplinary research andcollaborations among clinicians, epidemiologists, and basic scientists, andprovides a forum for sharing best practice in terms of i) collecting toxicity andnon-genetic risk factor data (particularly dose volume data); ii) genotyping
and resequencing technology; and iii) analysis of genetic associations with
toxicity. The consortium also provides a platform for large collaborative grantapplications. So far, the consortium has arranged two meetings, in Manchester, UK (2009) and New York (2010). As a first task, the consortium hascollected clinical and genetic data on 5,603 patients from 20 published andunpublished studies, and is conducting a meta-analysis on associations between SNPs in TGF and normal tissue toxicity.
References:
1. Barnett GC, West CM, Dunning AM, et al. Normal tissue reactions toradiotherapy: towards tailoring treatment dose by genotype. Nat. Rev.
Cancer 9: 134-142, 2009.
2. Andreassen CN. Searching for genetic determinants of normal tissue
radiosensitivity–are we on the right track? Radiother. Oncol. 97: 1-8,
2010.
3. West C and Rosenstein BS. Establishment of a radiogenomics consortium. Radiother. Oncol 94: 117-118, 2010.
4. West C, Rosenstein BS, Alsner J, et al. Establishment of a Radiogenomics Consortium. Int. J Radiat. Oncol Biol. Phys. 76: 12951296, 2010.

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368 speaker
STEM CELL / PROGENITOR CELL THERAPY TO INHIBIT RADIATION INJURY
R. Coppes1
1

U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN Departments of Radiation Oncology and Cell Biology, Groningen,
Netherlands
GEN ,During the treatment of cancer with radiotherapy inevitably normal tissues arealso exposed to ionizing radiation. Many factors play a role in the responseof tissues to irradiation, but ultimately the ability of stem cells to reconstitute functional cells determines the onset and the severity of the radiation
side-effects. Stem/progenitor cell therapy provides a potential prevention ortreatment of radiation-induced normal tissue damage. Several stem cell types
are being investigated for their potential use in stem/progenitor cell therapy:
embryonic stem cells, induced pluripotent stem cells, tissue adult stem cells(ASC), mesenchymal stem cells (MSC) and epithelial progenitor cells (EPC). Of these the last three are used as or are close to clinical application andwill be discussed in the current presentation.
The maintenance and repair of the tissue integrity are the primary roles of
the tissue stem cell. Stem cells are undifferentiated reside between differentiated cells and are able to self-renew to prevent aging. They can produce cells that differentiate and proliferate to yield all specialized cell typesof a specific tissue. In contrast, progenitor cells although capable of producing specialized cell types have a limited life-span as they are incapableof self-renewal. For the normal tissue it is of eminent importance to spare
the tissue stem cells. Recently, it became apparent that the tissues stem
cells may not be evenly distributed over the tissue. Here specific sparingof high stem cell density regions may be preferable. If it is unfeasible tospare the normal tissue, stem/progenitor cell therapy may be an option. One
option which has been extensively addressed is the stimulation of surviving
stem/progenitor cells using growth factors. This approach has been shownpreclinical to potentially be promising in e.g. gut and salivary glands albeit
only when sufficient stem/progenitor cell remain after irradiation. Another option would be the transplantation of supportive MSC which secrete growth
factors and modulate immunogenicity. However, although depending on themodel some transdifferentiation has been observed also the regenerative potential of these cells depend on the number of surviving stem/progenitor cells.
For tissue in which vascular damage is the main cause of organ dysfunction after irradiation, transplantation or mobilisation of bone marrow derived
EPCs and vascular progenitor cells may result in inhibition of normal tissue
damage, although also for such therapies survival of local stem/progenitor
cells seems to be a prerequisite. Independent from the number of surviving
stem/progenitor cells ASC transplantation seems to be a promising therapy.
For mouse salivary gland the potential of such therapies has been shown andare currently being translated to clinical application. Recent developments will
be discussed. The application of stem/progenitor cell therapy in all its forms
to reduce normal tissue effects will have a tremendous impact on radiation
oncology in the near future.
369 speaker
UNDERSTANDING AND MANIPULATING CYTOKINE NETWORKS
INVOLVED IN DEVELOPMENT OF RADIATION INJURY
H. P. Rodemann1
1
U NIVERSITÄTSKLINIK FÜR R ADIO -O NKOLOGIE, Biology, Tübingen,Germany
Abstract not received.

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P ROFFERED PAPER

Proffered paper
Physics Proffered Papers 8: Highlights - Small andnon-reference field Dosimetry
370 oral
EVALUATION OF THE ANISOTROPIC ANALYTICAL ALGORITHM
FOR SMALL FIELD DOSIMETRY AND ITS INFLUENCE IN RAPIDARC
DELIVERY
C. L. Ong1 , J. Cuijpers1 , S. Senan1 , B. Slotman1 , W. Verbakel1
1

W EDNESDAY, M AY 11, 2011

P ROFFERED PAPER

S 147

371 oral

372 oral

373 oralNEW HIGH RESOLUTION 2D LIQUID FILLED IONIZATION CHAMBER ARRAY FOR SMALL FIELD MEASUREMENTS
L. Brualla Gonzalez1 , A. Vicedo1 , D. M. González-Castaño2 , A. Gago
Arias2 , J. Pardo Montero2 , A. Pazos Alvarez2 , M. Bermúdez3 , F. Gomez2 ,J. Rosello1
1
H OSPITAL G ENERAL DE VALENCIA _ERESA, Servicio de Radiofísica,
Valencia, Spain
2
U NIVERSIDAD S ANTIAGO DE C OMPOSTELA, Particle Physics
3
S IEMENS, Servicio Técnico, Tres Cantos, Spain

DOSIMETRIC STUDY AND ARRAY ASSESSMENT OF PLASTICSCINTILLATION DETECTORS IN STEREOTACTIC RADIOSURGERYCONDITIONS
J. C. Gagnon12 , D. Thériault1 , M. Guillot12 , L. Archambault12 , S. Beddar3 ,COMPARISON OF DIODE, DIAMOND AND SCINTILLATION DETECTORS FOR THE MEASUREMENT OF SMALL FIELD OUTPUT
FACTORSK. Warrener12 , A. Ralston3 , P. Liu34 , D. McKenzie4 , N. Suchowerska34
1
C ENTRE FOR M EDICAL R ADIATION P HYSICS , U NIVERSITY OF W OLLON GONG , Wollongong, Australia
2
I LLAWARRA C ANCER C ARE C ENTRE, Medical Physics, Wollongong,
Australia
3
S YDNEY C ANCER C ENTRE , R OYAL P RINCE A LFRED H OSPITAL, Radiation
Oncology, Camperdown, Sydney, Australia
4
U NIVERSITY OF S YDNEY, School of Physics, Sydney, Australia

VU U NIVERSITY M EDICAL C ENTER, Amsterdam, Netherlands

Purpose: To investigate the accuracy of the anisotropic analytical algorithms(AAA) for a variety of small fields in homogeneous and heterogeneous media,
and its influence on the dosimetric accuracy of RapidArc plans.
Materials: Dose distributions calculated using AAA version 8.6.15 (AAA8)
and 10.0.25 (AAA10) were compared to measurements performed with
GafChromic EBT film, using phantoms made of polystyrene or a combination of polystyrene and cork. The accuracy of the algorithms calculated using
grid resolutions of 2.5 mm and 1.0 was investigated for different small fieldsizes, and for RapidArc plans (head and neck, small meningioma, and lung).
Additional plans were optimized to create excessive multileaf collimator modulation and measured on a homogenous phantom. Gamma evaluation criterion of 3% dose difference and 2- or 1-mm distance to agreement (DTA) wereapplied to evaluate the accuracy of the algorithms.
Results: AAA8 underestimated the peak doses for a 1 cm x 1 cm field inpolystyrene and cork by up to 5% and 10%, respectively (Figure 1a). Both
AAA10 and finer grid calculations improved the accuracy of AAA calculations.
Using AAA10 and a finer calculation grid of 1.0 mm reduced these deviations
to ≤ 2%. At the direction parallel to the MLC leaves, AAA predicted a broader
penumbra than the measurements, especially in cork (Figure 1b and 1c). In
head and neck plans, the accuracy of AAA correlated significantly with theamount of monitor units generated (p<0.05). Measurements demonstrated
higher dose modulation than calculations, especially in plans with more monitor units. For a RapidArc meningioma plan, AAA8 failed to identify a sharp
peak within the target, resulting in dose underestimation of 13%. With AAA10
calculated using a grid of 1.0 mm, this deviation reduced to < 3%. In low
density cork, AAA8 underestimated the average dose for a lung plan by 4%(maximum 12%), with up to 21% of the surface failing the gamma criterion;
whereas the introduction of a small polystyrene sphere (to imitate the presence of a tumor), resulted in only 7% and 1% of the surface failing the gamma
criterion (3% dose and 2 mm DTA), using AAA8 and AAA10, respectively.

W EDNESDAY, M AY 11, 2011

Purpose: To present the performance of a new 2D liquid filled ionizationchamber array in the verification of small field delivery.

Materials: We have developed a new 2D array for the verification of small
fields. It consists in an 8x16 array of square shaped, plate parallel 2 x 2 mm2
liquid filled ionization chambers with a distance between chambers of 2 mm.
The detector gap is 0.5 mm and it is filled with non-ultrapurified isooctane.
Polarization voltage is +1000 V. The readout of the chambers is performed
with a XDAS board with an Ethernet interface.A complete characterizationof the dosimetric response of the device has been carried out. The following aspects have been studied: i) Dose rate dependence (both varying thedose-per-pulse and pulse repetition frequency)ii) stability and reproducibilityiii) response linearity with monitor units/dose iv) output factor measurementv) beam incidence dependence (isotropy) vi) energy dependence.The
results were compared with air filled ionization chamber, radiographic film or
diode measurement depending on the test. The device was also used toverify IMRT radiosurgery treatments and the results of the full delivered treatments were compared with radiographic film results.
Results: The dose rate dependence check when varying linac dose-perpulse shows a small recombination deviation from linearity (below 1%) . Maximum anisotropy is less than 6%, which can be considered acceptable considering a multiincidence treatment delivery. The detector shows very good
agreement with the other dosimeters employed except for small effects (alsounder a 1%) related to dose rate dependence. These small recombination
effects observed can additionally be parametrised and corrected for (on-line).
The gamma analysis of IMRT treatment verifications exhibits excellent agreement when compared with radiographic film.

L. Gingras12 , L. Beaulieu12
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Radio-oncologie, Quebec, Canada
2
U NIVERSITÉ L AVAL, Département de Physique, Génie Physique etd’Optique, Québec, Canada
3
U.T. M.D. A NDERSON C ANCER C ENTER, Houston, TX, USA
1

Purpose: To compare the performance of a plastic scintillation detector(PSD) to micro ion-chamber (IC), Gafchromic EBT2 films, shielded diode (SD)and unshielded diode (UD) in small fields, stereotactic radiosurgery conditions and assess a new 2D crosshair array prototype adapted to radiosurgery
dosimetry.
Materials: The PSD is composed of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain Crystals, Paris, France) coupled to apolymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co.,
Ltd., Tokyo, Japan). Output factors (OF) for apertures used in radiosurgery
ranging from 4 mm to 40 mm in diameter have been measured with all detectors. The PSD crosshair array (PSDCA) is a water equivalent device made up
of 49 PSD contained in a 1.63 cm radius area. Dose profiles measurements
were taken for radiosurgery fields using the PSDCA and were compared toother dosimeters. A stereotactic radiosurgery treatment delivered with 4 noncoplanar arcs was planned, using Xknife (Integra Radionics Burlington, MA),and was delivered on a spherical phantom in which an UD, IC or PSD wasplaced.
Results: OF measured with the PSD have a mean difference of 1.3% with
EBT2 films normalized to a 10x10 cm field, and 1.0% when compared withUD measurements normalized to the 35 mm cone OF. Gamma values were
calculated to compare dose profiles of 4, 10 and 40 mm cones measured
using the PSDCA, with dose profiles from EBT2 and UD measurements andshowed 99.1% and 100.0% respectively of detector passing the gamma acceptance criteria of 0.3 mm and 2%.

The dose measured by the PSD for a complete stereotactic radiosurgery
treatment delivered with a 35 mm cone was found to be within 1 % of theplanned dose For a 5 mm cone, the measurement of a similar treatment plan
was within 1.4% with the planed measurement corrected for its SD-based
OF. Furthermore, volume averaging of the IC can be observed for the 5 mm
aperture where it differs by as much as 9.1% compared to the PSD measurement. The angular dependency of the UD was also observed, unveiled by anunder-response around 2.6% for both 5 and 35 mm aperture plans.
Conclusions: OF and dose profiles measurements performed respectively
with the PSD and the PSDCA were in agreement with those obtained with the
UD and EBT2 films. For stereotactic radiosurgery treatment verification, thePSD gives accurate results compared to the planning system and the IC once
the latter is corrected to compensate for the averaging effect of the IC. The
PSD provides precise results when used as a single detector or in a dense
array, showing a great potential for stereotactic radiosurgery QA applications.

Conclusions: AAA10 improves the accuracy of dose calculations, and a gridof 1.0 mm is superior to using 2.5 mm, although calculation times increasedby factor of 5. A suitable upper MU constraint should be assigned during
optimization to avoid plans with high modulation. Careful quality assurance
should be performed for plans with a relative high number of monitor units,
and for planning target volume (PTV) regions containing large area of low
density tissue. Calculations using 1 mm grid resolution are recommended forplans with high modulation.

Conclusions: This liquid filled ionization chamber array has been designed
to achieve a 2D map with outstanding spatial resolution. The intercomparison
with other standard dosimeters demonstrate that this device is a real alternative for on-line dose distribution measurements in small fields, allowing theimmediate determination of output factors and profiles of such therapeutic
beams. The same technique could be used in standard field dosimetry verification allowing a multipoint measurement that delivers not only the dose but
the local dose gradient.

Purpose: The distinguishing characteristics of small MV photon fields include
source occlusion and lack of charged particle equilibrium. These combinedwith the need for a dosimeter with a small sensitive volume and minimal field
perturbation have resulted in significant uncertainty in the determination ofdose. This study provides evidence to assist in the selection of the optimal
dosimeter and methodology for small fields conditions.
Materials: We compared the performance of a PTW diode E (type 60012),
a PTW diamond detector (type 60003) and an air-core scintillation dosimeter(Lambert 2009) for the measurement of in-water and in-air output factors insmall fields defined by MLCs (5 mm to 30 mm) and SRS cones (4 mm to
30 mm) on a Varian Novalis linear accelerator. In-water measurements were
performed with conventional geometry in a water tank. In-air measurements
were performed using brass mini-phantoms with either a cap design (Zhu
2009) or rods with zero thickness sidewall (McKerracher 2007) of varying
heights and widths.
Results: The in-water output factors determined using the three detectors
agreed well down to 10 mm field size. For smaller fields, the diode and diamond detectors read higher and lower than the scintillation detector respectively. However, after applying perturbation correction factors to the diodereadings and volume averaging correction factors to the diamond readings(Francescon 2008), the three detectors agreed within 2.5%. Normalised inair output factors were independent of brass mini-phantom height (from 2 15 mm) but strongly dependent on cap or rod width. The use of a range ofmini-phantoms and detectors matched to the appropriate field sizes is criticalto avoid introducing significant measurement errors.

Conclusions: This study confirms the validity of previously published correction factors for diode and diamond detectors in small fields. The scintillation
detector has a clear advantage because it can be used without the need forcorrection factors due to its water equivalence and small size. For accurate
in-air output measurements in field sizes down to 4 mm it is recommended touse a range of mini-phantoms.Acknowledgement: This work has been supported by a project grant from NHMRC Australia.
374 oral
SMALL FIELD MANAGEMENT FOR RAPIDARC DELIVERY: COMPARISON BETWEEN MEASUREMENTS AND CALCULATIONS
A. Clivio1 , A. Fogliata1 , G. Nicolini1 , E. Vanetti de Palma1 , L. Cozzi1
1
I STITUTO O NCOLOGICO DELLA S VIZZERA I TALIANA, Medical Physics,
Bellinzona, Switzerland
Purpose: The management of small fields for RapidArc treatment is a key
issue for stereotactical treatment with this technique. A comparison study
between measurements and calculations is presented.
Materials: Comparisons in terms of PDD, profiles and MU calculations of simple open square small fields was performed in order to assess the capabilityof the treatment planning system (TPS) and related algorithms to compute
such a stereotactical openings. Field sizes ranged from 3x3 cm2 down to 1x1
cm2 . A 6MV beam from a Clinac 2100iX equipped with MLC-120 Millennium
was used. Measurements were done with a diamond Riga-PTW detector of

S 148

P ROFFERED PAPERa sensitive surface of 4mm2 and a thickness of 0.4mm in a waterphantom.
Calculations were done in Eclipse (Varian TPS) and the Anisotropic Analytical Algorithm (AAA) versions 8.6, 8.8 and 10.0 as well as the newer Acuros
XB versions 10.0 and 11.0 (pre-clinical) photon dose calculation algorithms.
Spot size setting was 0mm for AAA and 1mm for Acuros XB. Calculation grid
was set to 1mm in all cases. Beam data for each algorithm included measurements for field sizes down to 1x1 cm2 .Four RapidArc cases were simulated,with jaw settings to 3x3, 2x2 and 1x1 cm2 , the last having two plans, onewith high and one with low modulation. One arc per case was planned, from110◦ to 250◦ CCW gantry angles, collimator to 45◦ . Plan and measurements
were performed in the PTW Octavius phantom. The same diamond detector
was used for data acquisition. A gamma analysis as per the pre-treatment
QA based on EPID images converted to dose (through the GLAaS algorithm)
was performed with 2mm, 2% and 3% as DTA and delta dose criteria.
Results: Concerning PDD of small static fields, agreement was found within<1% for Acuros XB, 1-2% for AAA 10.0; larger differences can be found forearlier AAA in the first 3-4cm depth. MU difference between calculations andmeasurements was within 0.5% for Acuros XB, within 1% for AAA. Measured
profiles were well reproduced by all calculations. After having assessed thereliability of delivery and calculations for simple small static fields, the RapidArc cases were analysed. Dose output was compared between diamondmeasurements and isocentre dose considering a sphere of 2mm radius. Maximum dose difference was within 3% for all cases. Pre-treatment QA presented a gamma agreement index of more then 95% for 3x3 and 2x2 cm2cases, and between 80 and 90% for the 1x1 cm2 cases.
Conclusions: RapidArc can be considered a safe solution for stereotactical treatment in terms of delivery. The two algorithms AAA and Acuros XB
implemented in Eclipse are accurate in this context.
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EXPERIMENTAL SMALL FIELD OUTPUT FACTOR ANALYSIS FORVARIOUS DIODE DETECTOR AND ACCELERATOR COMBINATIONS
G. Cranmer-Sargison1 2 , S. Weston3 , N. Sidhu1 4 , D. I. Thwaites3 2
1

S ASKATOON C ANCER C ENTRE, Saskatoon, Saskatchewan, Canada
U NIVERSITY OF L EEDS, Leeds, United Kingdom
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom
4
U NIVERSITY OF S ASKATCHEWAN, Saskatoon, Canada
2

3

Purpose: The goal of this work was to measure 6 MV small field output factors (OFs) using the IBA stereotactic field diode (SFD) and the PTW T60008,
T60016 and T60017 field diodes on both Varian iX and Elekta Synergy accelerators, and to establish the uncertainty estimates for the experimental
values.
Materials: Data was acquired at depths of 1.5, 5.0 and 10.0 cm and fieldsizes of 3.0, 1.0, 0.9, 0.8, 0.7, 0.6 and 0.5 cm. Three isocentric measurements comprised of 5 readings were made to calculate an experimental OF (± uncertainty) with respect to a field size of 5.0 cm. The coefficient of variation (CV) was calculated to characterize the precision associated with each detector-linac combination. Another measurement set wasmade to investigate the influence of jaw position accuracy. The jaws (Varian) or MLC/diaphragms (Elekta) were repositioned between each reading.
The generality of the characterisation was investigated for each treatment
machine by repeating the measurements using the T60017 diode on multiple
beam matched machines. All data is presented at a 95% confidence interval.
Results: As expected for field sizes smaller than 3.0 cm, the measured OFs
were not consistent across all detectors. However, the SFD and T60017 data
was found to be nearly equivalent, as were the T60008 and T60016 results.
Interestingly this correlates with detector design those being energy compensated (T60008 and T60016) and those that are not (SFD and T60017).
The experimental OF unbiased percent uncertainty was found to be nearlyconsistent across all detector-linac combinations: less than ±0.25% for the
3.0 cm field size, increasing to approximately ±1.25% for the smallest fieldsizes. SFD measurements did reveal an experimental uncertainty greaterthan ±2.00% which may hint at detector stability but this would have to beinvestigated further. At field sizes greater than 1.0 cm, the average CV wasvery nearly constant for all detector-linac combinations at 0.05%. As the fieldsize was reduced to 0.5 cm the CV increased to 0.10% and 0.15% on the
Varian and Elekta linacs respectively. The additional reduction in precisionfound for the Elekta measurements is thought to be the result of variationsin the electron spot size and/or shape incident on the target. The CV did
increase when the jaws (Varian) or MLC/diaphragms (Elekta) were repositioned between readings yet a paired t-test revealed the differences not to bestatistically significant at the p = 0.05 level. This was also the case for all
measurements made on the beam matched linacs.
Conclusions: Experimental 6 MV small field OFs can be measured with thediode detectors used in this study to within ±1.25%. The precision of any one
set of measurements can be characterized with a CV approximately 0.10%.
However, measurement accuracy as it relates to the actual relative dose towater would require Monte Carlo simulation.

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W EDNESDAY, M AY 11, 2011376 oral
THE USE OF ALANINE/EPR FOR THE CALIBRATION OF HELICALTOMOTHERAPY BEAMS
R. Thomas1 , S. Duane1 , P. Sharpe1
1
N ATIONAL P HYSICAL L ABORATORY, Radiation Dosimetry, Teddington,
United Kingdom
Purpose: TomoTherapy Hi-ART machines cannot deliver the flattened,
10x10 cm2 beam required by dosimetry protocols. This work reports the useof alanine/EPR dosimetry to provide a traceable absorbed dose calibration ofion chambers directly in the treatment beam. To date, all TomoTherapy machines installed in the UK have been calibrated this way [Duane et al., 2006]
and a summary of the results will be presented.
Materials: Alanine/EPR dosimeters are small, water-equivalent and provide
a suitable means to transfer absorbed dose from the reference conditions inwhich a primary standard measurement is made, to non-reference conditions
such as are found in helical TomoTherapy. Ion chambers of type A1SL andNE2611 have been calibrated using alanine in helical and in static treatmentswith two different solid water-equivalent phantoms. The NE2611 chamber has
also been calibrated at NPL in a range of MV photon beams under standard
reference conditions, and the result expressed as a function of the quality
index TPR20/10.The static TomoTherapy beam calibration of both chamber
types was performed in a rectangular full scatter phantom. The A1SL chamber was also used to measure a beam quality parameter TPR20/10(Tomo) for
the same 5x10 cm2 beam. This parameter, although not conforming to thedefinition of quality index, was used to evaluate the NE2611 calibration forcomparison with the direct calibration using alanine.The helical beam calibration was performed at the centre of a cylindrical phantom, 10 cm in diameterand 20 cm long. This phantom was CT scanned and a treatment preparedusing the TomoTherapy Planning System, to deliver a uniform dose of 3 Gy toa concentric cylindrical target volume, 8 cm in diameter and 10 cm long. Thiswas repeated for each beam width (1 cm, 2.5 cm and 5 cm) with the phantom
concentric with the machine, and also for the 2.5 cm beam with the phantom
offset from the machine axis.In this work the definitive calibration of machine
output, for each beam width, is based on the corresponding alanine/EPR determined absorbed dose.
Results: The figure shows alanine/EPR based correction factors for theNE2611 chamber, normalised to 60 Co, in all TomoTherapy beams measured
to date (points). Also shown is the quality dependent correction, kQ, basedon calibration against the primary standard in NPL linac beams (curve).

Physics Proffered Papers 9: Challenges in Treatment Planning
377 oral
BENCHMARK OF A NEW ALGORITHM FOR DOSE CALCULATIONIN RT USING A GRID-BASED BOLTZMANN EQUATION SOLVER
M. B. Kyed Jørgensen1 , L. Hoffmann1 , H. S. Rønde2 , J. Petersen1
1

A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
2
V EJLE H OSPITAL, Department of Medical Physics, Vejle, Denmark
Purpose: The Acuros XB advanced dose calculation algorithm (Acuros XB)
was developed to improve the accuracy and speed of external photon beamtreatment planning. Acuros XB uses a grid-based technique to solve the Linear Boltzmann transport equation and directly accounts for the effects of heterogeneities in patient dose calculations. The aim of this study is to test theaccuracy of the Acuros XB algorithm for heterogeneous media (lung, bone
and tissue) and homogeneous media (water) by comparison with film measurements and measurements in water. The calculations in heterogeneous
media were also performed with the Anisotropic Analytical Algorithm (AAA).
Materials: All fields and test plans were calculated in Eclipse (Varian Oncology Systems, Ca) for both 6 MV and 15 MV photons and compared tomeasurements performed at a Varian accelerator.In connection with the implementation of Eclipse, output factors, profiles and depth doses for squaresymmetric fields were measured in a PTW water tank with a diamond detector(PTW, Freiburg, Germany) and a RK ion chamber (Precitron, Sweden). Furthermore, various asymmetric fields, fields with different MLC configurationsand various source skin distances (SSD) (80 cm to 130 cm) were measured
in the water tank for comparison with the Acuros XB algorithm. Eight testplans were calculated on a CIRS Thorax Phantom (CIRS, Va) consisting oftissue, lung and bone equivalent plastic materials. Dose distributions within
the phantom were measured for selected transversal slices with Gafchromic
EBT dosimetry films (ISP, NJ). The 2D dose distributions were evaluated in
VeriSoft (PTW Freiburg, Germany) with a Gamma criterion of 3 % in doseand 3 mm in distance to agreement (DTA), G(3,3).
Results: The accuracy of the Acuros XB algorithm for profiles at five different
depths is within 1%, 1mm except outside the field. For the depth dose curves,the mean value of the deviations is within 1 mm/1 % for 6MV and 2mm/1%
for 15MV. The output factors are within 1%. Similar results were obtained for
output factors of asymmetric fields, fields with different MLC configuration andfields with various SSDs.Overall, the measured and calculated 2D dose distributions of the CIRS Thorax Phantom showed good agreement. The numberof points meeting the G(3,3) criterion was higher for the plans calculated with
the Acuros XB algorithm than with the AAA algorithm, with both algorithms
failing at low doses (< 0,1 Gy) and on gradients. On average, the number ofpoints meeting the G(3,3) criterion was 96 % for the Acuros XB algorithm.
Conclusions: The dose calculations performed with the Acuros XB algorithm
in both homogeneous and heterogeneous media display a good agreementwith measurement. Film measurement of the eight test plans showed that
the Acuros XB algorithm is superior to the AAA algorithm in heterogeneous
media.
378 oralConclusions: The static beam calibration is an instance of the machine specific reference field proposed by the IAEA Working Group [2]while the helical beam calibrations are examples of their plan class specific reference field. The static beam calibration results indicate that the factor
fmsr ,frefkQ

msr ,Q

that corrects for the differences in field size and beam quality between thecalibration under reference conditions and the calibration in the smaller,
flattening filter-free TomoTherapy beam, is close to unity. Similarly theanalogous correction factors
fpcsr ,frefkQ

pcsr ,Q

for these helical beams are also close to unity. For these fields at least,the dosimetry protocol would reduce to a straightforward application of thecalibration coefficient determined in conventional reference conditions.

FUNCTIONAL FORMS FOR PHOTON SPECTRA OF CLINICAL
LINACS
E. Ali1 , D. Rogers1
1

C ARLETON U NIVERSITY, Physics, Ottawa, Canada

Purpose: In a clinical photon beam, the spectrum is a pre-requisite fordose calculations in treatment planning systems and for calculations of otherspectrum-averaged dosimetric quantities. Describing spectra using a functional form with a few free parameters is desirable because it is compact,
it facilitates virtual source modeling, and it tames the classic ill-conditioned
problem of unfolding spectra from depth dose or transmission measurements.
The literature has scattered parameterization models which are not rigorously
benchmarked or compared to each other. This study thoroughly evaluates
existing functional forms and proposes a new form that addresses existing
limitations.
Materials: Nine different functional forms published between 1989 and 2008
are evaluated, and a new functional form is proposed. The proposed form
has five parameters, including the maximum energy and the magnitude of
the 511 keV annihilation peak. The proposed function uses general featuresof linac heads and the common terms in thin target formulae from the classic bremsstrahlung review article of Koch and Motz. Fits are done for theenergy fluence, not the fluence, because the energy fluence has a smaller
range of variation, reveals better the discrepancies at the higher end of thespectrum, and is a more direct indicator of dose. Fitting is done using thestandard LevenbergMarquardt least squares algorithm. A library of about 70
high resolution Monte Carlo spectra is used for testing all functional forms.

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The library includes spectra from Varian, Siemens and Elekta machines (allwith and without a flattening filter, on- and off-axis), Tomotherapy (on- and offaxis, treatment and imaging modes), Cyberknife and research spectra (NRC
Vickers linac and NPL linac).
Results: Existing functional forms are found to have one or more of the following limitations: too simple to accommodate spectra from all current linac
beams, unjustifiably too complex to be practical, not based on physics andthus prone to yielding non-physical spectra when used in spectral unfolding,or have tails and thus are inaccurate in maximum energy estimation. Whentested against the full library of spectra, the proposed functional form shows
an average absolute deviation of ~1 %. Estimates of the maximum energy,
peak energy and fluence-weighted mean energy were, on average, within 4%, 3 % and 0.8 % of their true values, respectively. Sample fits are shown in
the figure. In separate studies we show that the proposed functional form iswell-behaved (and thus not over-parameterized) when used to unfold spectrafrom depth dose or transmission measurements.

Conclusions: The proposed functional form is accurate within 1 %. The
function is simple, physics-based, has reasonably few parameters, and is
flexible enough to accommodate photon spectra from all currently used linacs.
379 oral
VOXEL BASED METHOD TO GENERATE CT EQUIVALENT IMAGESFROM MR IMAGES FOR TREATMENT PLANNING PURPOSES
T. Nyholm1 , A. Johansson1 , M. Karlsson1
1

U MEÅ U NIVERSITY, Department of Radiation Sciences, Umeå, Sweden

Purpose: The voxel intensities in CT images are directly related to the electron density. CT is therefore a natural choice as a basis for dose calculations
and patient positioning in external radiotherapy. There is however an emerging interest in replacing the CT with MR because of the superior soft tissue
contrast obtained with magnetic resonance imaging. The main challenge isthe extremely short T2 relaxation time of bone, 0.40.5 ms, making discrimination between bone and air difficult using traditional MR sequences. Therefore, ultra short echo time (UTE) sequences can be used to acquire signal
from bone.The aim of the present work was to develop a voxel based method
for generating a substitute CT (s-CT) image from an MRI examination.
Materials: We made use of five clinical datasets with MRI and CT data of thehead. Each of the five patients was imaged with CT and three MR sequences:
two dual echo UTE sequences (TE = 0.07 and 3.76 ms) with different flip angles (10◦ and 60◦ ), and one conventional T2 weighted sequence. All MR
images were acquired on a Siemens Espree 1.5 T scanner. For each patient
the MR and CT images were co-registered and for each MR image two newimages were derived by calculating the mean value and standard deviationof the voxels in a 27-voxel neighborhood around each voxel. The distributionof voxels in this 16-dimensional (5 MR images + CT) intensity space wasapproximated by a mixture of 20 multivariate Gaussians using the Expectation Maximization (EM) algorithm with k-means initialization. The model wastrained on the MR and CT data from four patients at a time and applied to
the MR data of the remaining patient to generate a substitute CT image. This
procedure was repeated for all five combinations of training and validation
data in a leave-one-out cross-validation (LOOCV) procedure. The substituteCT was compared to the real CT for each patient by calculating the mean
absolute error (MAE) in Hounsfield units (HU).
Results:

S 150P ROFFERED PAPERW EDNESDAY, M AY 11, 2011
out using pre validated PHSP files and the DOSXYZnrc code. VSM calculations were carried out using DOSXYZrt, a modified version of DOSXYZnrc
which includes support for histogram-based particle sampling.
Results: Our study has shown that for a non bow-tie filtered beam, 92%of the photons exiting the CBCT unit last interacted in the X-Ray target, 3%
in the filtration cone and 5% elsewhere. For bow-tie filtered beams, 85%of the photons last interacted in the target, 3% in the filtration cone, 10%
in the bow-tie filter and 5% elsewhere. For each source in the VSM, twoplanes were used to generate particles: one origin plane and one sampling
plane. For both target and filtration cone, the origin plane was set to the X-ray
focal spot and the sampling plane at 100 cm from the target. For the bow-tie
filter source, the origin plane was set at the back of the filter. The particle’s
energy spectrum was modelled and sampled separately. Figure 1 depicts theagreement between full MC and VSM calculations for the dose deposition inwater of a clinical CBCT beam using large pelvis CBCT scans (120 kV, L20,
F0).

W EDNESDAY, M AY 11, 2011
values (bony structures = 400; lung = -750 or air in the rectal balloon = -1000
and all other structures assumed to be water-equivalent). In the third approach all structures (ROI mapping) were overridden with the HU from planning CT for each patient. The accuracy of dose calculation was analyzed by
DVH comparison.
Results: Comparison of PTV (coverage with prescribed dose and meandose) indices is presented on the Figure 1 (a-b). For prostate cases PTV
coverage and mean dose were underestimated with CC approach on average by 3% compared to planning CT, whereas WAB and ROI mapping overestimate these indices by 1.5% and 0.6%, respectively. Maximum doses forrectum and bladder were underestimated by CC method by 1.5% and overestimated by 1.8% by the two other approaches. All three techniques showed
lower volume of rectum and bladder covered with the 50% isodose (10 ccm
for 4F-box and 3.5 ccm for IMRT) compared to the CT plan (Fig. 1 c). Dose
difference for femoral heads was below 1% in all three approaches. For lungcases mean difference in PTV coverage resulted in underestimation by 5%with CC approach and overestimation by 0.5% using the two other methods.
With regard to the OARs, underestimation of maximum dose to lung, spinal
cord and esophagus by 0.5-1% was shown, whereas mean lung dose was
0.5% higher in all three approaches (Fig. 1 d).

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S 151(mean±2SD) of 4.4%±2.1% of Dmax, 6.0%±3.1% of D0.1cc, 7.2%±2.3%
of D1cc and 8.9%±1.9% of D10cc. For the most exposed rib we measured 2.6%±3.8% of Dmax, 3.3%±3.0% of D0.1cc, 4.3%±2.5% of D1cc
and 5.0%±2.4% of D2cc. The mean difference of Dmax in ipsilateral lungwas 5.0%±3.1%. Parameter V20Gyαβ 3 was only available for 3 patients (0cm for the others) and showed a mean difference of 19.9%±0.9%.According
to the gynaecological case we found that the difference in D2cc of rectosigmoid was less than 1% and ~1% for the bladder. While same results wereobserved for the titanium applicator, the dose to the closeby bladder showed
up to 2.6% difference. Data on a more detailled study pending.
Conclusions: The results show a significant difference in DVH parameters
for APBI plans between the calculation algorithms of TG43 and BTE-based
Acuros BV for lung and close to the skin. It is usefull to check the dose distribution with Acuros BV especially for target structures near these regions. For
GYN the differences are expected to be smaller, although the impact of theapplicator material has to be studied in more detail.The Acuros BV softwaremodule was provided as an in-kind loan by Varian for research purposes only.
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4D DOSE CALCULATION FOR SCANNED PROTON BEAMS USING
A DEFORMING DOSE GRID AND SIMULATED 4DCT
D. Boye1 , T. Lomax1 , A. Knopf1
1

The LOOCV MAE for the all the s-CT images was 141 HU. A real CT is seenalong with a substitute CT in fig. 1 - Real CT (a, c, e, g) and a substitute CT
derived from MR images of the same patient (b, d, f, h). Differences between
real and substitute CT images were primarily found at the patient surface andat bonetissue and airtissue interfaces inside the head. The method did very
accurately distinguish bone from air, which has been a problem for other MR
based methods. All structures commonly used for patient positioning wereclearly visable in the DDR’s based on the s-CT.
Conclusions: Fig. 1. The fixation used during CT imaging is also seen in
the real CT images.The s-CT concept is very promising both to generate a
MR based basis for dose calculations and to serve as a reference for patient
positioning. As the method is voxel based, i.e. the transformation from MR
to s-CT is performed voxel by voxel, the method is not sensitive to untypicalanatomy, which is a large problem for atlas based methods.
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A VIRTUAL SOURCE MODEL FOR CONE BEAM CT DOSE DEPOSITION
E. Spezi1 , M. Fix2 , W. Volken2 , D. Frei2

Figure 1. Percentage depth dose (A) and lateral dose profile (B) for full MC(solid line) and VSM (symbol).
Conclusions: In this work we fully characterised the radiation output of akV CBCT unit. We demonstrated that it is possible to reconstruct a diagnostic CBCT X-ray beam using a VSM. We built a generalised VSM for target,
filtration cone and bow-tie filter and validated the VSM against full MC calculations. This is a first step towards the incorporation of concomitant dose
calculation in commercial treatment planning systems.References:
1. Med Phys. 2009 Jan;36(1):127-36.
2. Phys Med Biol. 2009 54(7):N93-N100.
3. Med Phys. 2009 36(9):4156-67.
4. Med Phys. 2004 31(11):3106-21.

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V ELINDRE C ANCER C ENTRE, Department of Medical Physics, Cardiff,
United Kingdom
2
I NSELSPITAL , U NIVERSITÄT B ERN, Division of Medical Radiation Physics,
Bern, Switzerland

FEASIBILITY OF CBCT-BASED DOSE CALCULATION: COMPARISON OF THREE HU ADJUSTMENT TECHNIQUES
I. Fotina1 , J. Hopfgartner1 , M. Stock1 , T. Steininger2 1 , D. Georg1
1
M EDICAL U NIVERSITY V IENNA , AKH, Department of Radiotherapy,
Vienna, Austria
2
V IENNA U NIVERSITY OF T ECHNOLOGY, Vienna, Austria

Purpose: The purpose of this work is to study the main source components
of kV X-ray beams generated by an on-board cone beam CT (CBCT) unit andto develop a virtual source model (VSM) that can be used for the calculationof concomitant dose due to the use of CBCT in IGRT.
Materials: A previously built Monte Carlo (MC) model of the Elekta XVI unit
[1-3] has been used to generate phase space (PHSP) files containing position, direction cosines, energy, weight, charge and position of the last interaction (ZLAST) for each particle exiting the CBCT unit. The PHSP files wereseparated accordingly to ZLAST and sub sources were generated for target,
filtration cone, and bow-tie filter using an enhanced version of the beampp
MC code [3]. Particles which last interacted in the remaining components of
the unit were neglected. After a detailed analysis of the position, direction andenergy spectrum characteristics of the sub sources, a histogram-based VSM
was built, following an approach previously used in MV external beam radiotherapy [4]. The VSM was used to sample particles’ position, direction andenergy for subsequent calculations of dose deposition in phantoms and validated against full MC simulations. Reference MC calculations were carried

Purpose: Decisions in adaptive radiotherapy can be performed on conebeam CT (CBCT)-based dose assessment. However, CBCT scans do notprovide correct Hounsfield Units (HU) and cannot be used directly for thedose calculation. The aim of this study was to compare the accuracy of threedifferent methods for HU adjustment in dose calculation on CBCT for different
patient geometries and planning techniques.
Materials: CBCT images of five prostate cases and five stereotactic lungcases were acquired on the XVI Synergy system (Elekta, Sweden). A four
field box (4F-box) and 7 beam IMRT plans were created on planning CT for
prostate while a 7 beam coplanar conformal technique was used for SBRT.
Dose calculation was performed with a Monte Carlo-based algorithm using
the iPlan treatment planning system (Brainlab, Germany). Structure sets andplans were transferred from planning CT to fused CBCT image sets and dose
was recalculated. For the first approach dedicated HU conversion curves(CC) based on the Catphan phantom and determined from abdomen or thorax acquisition protocol, were applied to CBCT images. The second method
called Water-Air-Bone (WAB) approach overrides the structures with fixed HU

1Figure 1. Box-plots of volume and dose differences for target volumes andOARs compared to planning CT data. Outliers are numbered by patient case.
Conclusions: ROI mapping and WAB provide alternative approaches to theconversion curves for CBCT dose calculation. They are less prone to theimage artifacts and dose differences for OARs are very small. WAB method
is associated with smallest workload, whereas ROI mapping provides more
personalized calculation.
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COMPARISON OF DVH-PARAMETERS FOR DOSE CALCULATIONBY TG43 AND BOLTZMANN BASED ALGORITHM ACUROS BV™
J. Scheuch12 , N. Nesvacil2 , A. Resch2 , R. Pötter2 , C. Kirisits2
1
K RANKENHAUS H IETZING, Department of Medical Physics, Wien, Austria
2
M EDICAL U NIVERSITY V IENNA, Department of Radiotherapy, Vienna,
Austria
Purpose: The aim of this study was to show the variation of DVH-parametersin 3D image guided Brachytherapy (BT) planning by using the Acuros BVDose Calculation Tool (Varian Medical Systems) instead of common TG43.
Acuros BV is based on the Boltzmann Transfer Equation (BTE) which is taking into account inhomogeneities such as anatomical and applicator material
since it uses electron density information from CT.
Materials: We analysed DVH parameters from CT-based treatment plans of
6 randomly selected patients treated with accelerated partial breast irradiation (APBI) by PDR-BT with flexible plastic implants in 2010. The treatment
planning system BrachyVision v10.0 (Varian Medical Systems) was used tocreate plans based both on standard TG43 and Acuros BV v1.4.0 algorithms.
Ipsilateral lung and the most exposed rib were contoured as regions of interest. A help structure for evaluating skin dose was delineated outside theskin surface. The corresponding DVH parameters were V20Gyαβ 3 for lung,
D0.1cc D1cc and D2cc for rib and D0.1cc D1cc and D10cc for the skin help
structure. Also for all structures Dmax was reported.In addition we compared
the DVHfor bladder and rectosigmoid of a cervix cancer treatment plan witha plastic tandem-ring applicator. A titanium applicator was simulated by datafrom a built in applicator library.
Results: As expected, dose in all regions of APBI was overestimated by
TG43 due to lack of taking into account missing backscatter from air inside
the lung and outside the body. For the skin structure we found differences

PAUL S CHERRER I NSTITUTE (PSI), Villigen - PSI, Switzerland

Purpose: The Center for Proton Therapy at the Paul Scherrer Institut (PSI) is
treating cancer patients with an active spot scanning technique. So far only
static tumors are treated, since moving target sites lead to interplay effects
compromising target dose homogeneity and target dose coverage.However, asecond generation proton scanning Gantry, which is optimized to treat moving
targets, is currently under construction at PSI. The treatment of moving target
sites is an ongoing project at PSI and here we propose a new method for time
resolved (4D) dose calculations using a deforming dose grid.
Materials: The analytical dose calculation at PSI is capable of simulating thecontribution of each pencil beam individually. Depending on gantry properties
proton pencil beams are delivered in a specific order and timeline, defined ina timestamp file. Dose calculation is performed per pencil beam on a gridof points (dose grid). According to the timestamp of each pencil beam, adisplacement and a change in radiological depth can be read in from previously calculated displacement- and density-variation-maps. Dose calculationis then performed on the deformed geometry accounting for patient motion.
This procedure is successively repeated for each pencil beam. Sources ofdisplacement- and density-variation-maps can be 4DCT datasets or 4DMRI
together with simulated 4DCT datasets.
Results: Our 4D dose calculation algorithm could produce the expected interplay pattern due to motion. Furthermore, anticipated target misses andtarget overshoots due to density changes in the beam path were reflected.
Figure 1 shows dose distributions for a spherical target volume in a homogeneous water phantom in a static scenario (a) and if left-right target motion witha peak-to-peak amplitude of 16mm was considered (b,c). Dynamic calculations were done for two different starting phases, resulting in different interplay pattern. Figure 1d) shows DVHs for all three scenarios. In the static casevery homogeneous dose in the PTV was obtained, reflected in a low D5-D95
value of 2.12. In the dynamic cases, dose homogeneity degraded, reflected
in higher D5-D95 values of 29.06 and 22.68. To restore dose homogeneity
in the dynamic scenarios motion mitigating techniques like rescanning arenecessary.

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comparison method identified all cases corresponding to 20 mm and 30 mm
needle movements, while some errors remained unidentified for smaller needle movements. The figure shows one case out of 20 where the needleto-needle dose comparison identified a simulated treatment error while theintegrated dose comparison did not.

W EDNESDAY, M AY 11, 2011
MU delivery error changed the TCP by 8.3% for the prostate plan. This plan
passed a gamma criterion of 5%/4mm but failed at 4%/4mm. Effects on theoropharynx plan were comparable but slightly smaller as the TCP was higher
so a lower gradient part of the dose response curve was being explored. A
4% MU delivery error in the oropharynx plan changed the TCP by 3%; thiserror was detected by a gamma criterion of 3%3 mm.
Conclusions: The most significant biological effect was a reduction in TCP
associated with MU delivery errors. For the plans tested, none of the errors
had a significant effect on NTCP. A gamma threshold of 3%/3mm or less was
required to ensure changes in TCP in the prostate were less than 6%. However, gamma criteria were insensitive to errors in mean dose and a criterion of
2% mean dose difference should be used in conjunction with the gamma criterion. With both criteria applied, a reduction in TCP of 4% would be identified
in the prostate plan.
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REAL-TIME VERIFICATION OF MLC-DRIVEN RADIOTHERAPYUSING AN OPTICAL ATTENUATION–BASED FLUENCE MONITOR
M. Goulet1 , L. Gingras1 , L. Beaulieu1
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Département de physique, Quebec, Canada

Conclusions: It was shown that the use of a deforming dose grid is a feasible
alternative to the common approach of warping time resolved dose distributions to a reference phase. Our approach does not require 4DCT data sets.
Motion information from 4DMRI can be used, which provides a large variety
of motion characteristics acquired in volunteers over many breathing cycles
without any assumption about periodicity. Thus, our approach enables a realistic verification of treatment plans for robustness against motion variations
during treatment delivery. Our advanced 4D proton dose calculations emphasize the necessity to use optimized target volumes.

Physics Proffered Papers 10: Monitoring Treatment Parameters
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ONLINE DETECTION OF IMPOSED BRACHYTERAPY ERRORS IN A
PHANTOM USING FIBER-COUPLED LUMINESCENCE DOSIMETRY
G. Kertzscher1 , C. E. Andersen2 , J. C. Lindegaard3 , S. K. Nielsen3 , K.
Tanderup3
1
R ISØ N ATIONAL L ABORATORY FOR S USTAINABLE E NERGY, T ECHNICALU NIVERSITY OF D ENMARK, Radiation Research Division, Roskilde, Denmark2
R ISØ N ATIONAL L ABORATORY FOR S USTAINABLE E NERGY, T ECHNICALU NIVERSITY OF D ENMARK, Roskilde, Denmark
3
A ARHUS U NIVERSITY H OSPITAL, Aarhus C, Denmark
Purpose: Treatment errors in afterloaded brachytherapy can occur by e.g.
exchanged guide tubes, mis-adjusted applicators, and reconstruction errors.
Our 1 mm diameter fiber-coupled luminescence probe fits inside standard
brachytherapy needles and has demonstrated capacity for online dosimetry
directly in the tumor region. The objective for the present work was to evaluate an improved read-out procedure and to demonstrate its ability to identify
imposed dose-delivery errors in a phantom study.
Materials: Thirteen parallel interstitial titanium needles were mounted on a
MUPID with relative positions according to a cervix cancer treatment plan
previously used at the hospital. Twelve of the needles were connected to a
Varian GammaMed Plus PDR afterloader housing a 14 GBq Ir-192 source,
while the remaining needle carried the dosimeter probe. Irradiations wereconducted with the needles submerged in a 30 cm x 25 cm x 26 cm watertank. Dosimetry was performed twelve times for the base case configurationin order to accurately assess the repeatability and to create a reference nullcase. The capacity of the in vivo system to detect errors was tested for 32
different simulated treatment errors with modified base case configurations.
Modifications involved swaping pairs of needles and displacing one or moreneedles 2, 5, 10, 20 or 30 mm. For this study, the sensitivity of the exisiting
luminescence dosimetry system was improved by using a two-channel optical filtration read out procedure in conjunction with the so-called saturated
radioluminescence signal from carbon-doped aluminum oxide .
Results: Dose measurements that deviated from null case mean values bymore than three standard deviations were defined as potential treatment errors. The standard uncertainty, calculated as the quadrature sum of the repeatability and a five percent measurement uncertainty, was smaller than
5.7% for all needle positions and the integrated dose. Based on the error
identification criteria, comparisons on a needle-to-needle basis correctly revealed discrepancies in 25 cases out of 32. Only five errors would be revealed
based on integrated dose comparisons for the complete pulse. The former

Conclusions: The results substantiated the conclusion from previous simulation studies that time resolved dosimetry can detect errors in brachytherapy
that are unseen by integrated dose measurements. Further improvements
could be achieved by comparing dose rates for individual dwell positions, orby introducing additional dosimeter probes.

Purpose: MLC-driven conformal radiotherapy modalities (e.g. IMRT, IMAT
and SBRT) are more subject to delivery errors and dose calculation inaccuracies than standard modalities. Fluence monitoring during treatment delivery
could reduce such errors by allowing an independent interface to quantify
and assess measured difference between the delivered and planned treatment administration. We developed an optical attenuationbased detector tomonitor fluence for the online quality control of radiotherapy delivery that can
detected both errors in delivered fluence and individual leaf position. The
purpose of the current study was to develop a theoretical framework of theinvention and to evaluate experimentally the detector’s performance.
Materials: We aligned sixty 27-cm scintillating fibers coupled to a photodetector via clear optical fibers in the direction of motion of each of the 60
leaf pairs of a 120 leaves Millenium MLC on a Varian Clinac iX, as shownon the included figure. The whole device is placed in the accessory trayof the linac so that fluence verification can take place during the treatment
delivery. We developed a theoretical model to predict the intensity of lightcollected on each side of the scintillating fibers when placed under radiation
fields of varying sizes, intensities, and positions. The model showed thatboth the central position of the radiation field on the fiber (xc) and the integral
fluence passing through the fiber (int) could be assessed independently ina single measurement. We evaluated the performance of the prototype by1) measuring the intrinsic variation of the measured values of xc and int as
a function of field size, 2) measuring the impact on the measured values ofxc and int of random leaf positioning errors introduced into IMRT fields and3) measuring the influence of the fluence monitor on the incoming radiation
beam.

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AN ANALYTICAL APPROACH TO ACCEPTANCE CRITERIA FORQUALITY ASSURANCE OF INTENSITY MODULATED RADIOTHERAPY
A. Carver1 , M. Gilmore1 , P. Mayles1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics Department, Bebington, Merseyside, United Kingdom
Purpose: A variety of phantoms and comparison criteria exist to perform
and analyse pre-treatment QA of complex Volumetric Modulated Arc Therapy(VMAT) treatment plans. Previous studies have measured the sensitivity ofvarious pre-treatment QA procedures in terms of the dosimetric error. The
aim of this study was to relate the acceptance criteria used in practice to theclinical significance of deliberately introduced errors.
Materials: Errors were simulated in two RapidArc treatment plans, one
prostate plan and one oropharynx plan. Simulated errors were: a uniform
MLC offset (up to 2.5 mm), a monitor unit (MU) delivery error (up to 4%) andgravity sag of up to 2.5 mm. These plans were then delivered on a RapidArc
linac using the Delta4 phantom to measure the fields. The Delta4 analysis
software was used to determine the gamma index pass rate using thresholds
from 2%/2 mm to 7%/4 mm. Tumour Control Probability (TCP) and Normal
Tissue Complication Probability (NTCP) were calculated from the dose volume histograms (DVH) to assess the clinical significance of the errors as afunction of the magnitude of the error in the plan. (NTCP was for rectal bleeding and loss of parotid gland function as appropriate.)
Results: MU errors were found to have a much larger effect on the TCP
than the MLC positional errors. The effect on Organs At Risk (OARs) was
found to be generally small for all errors. The gravity sag effect increased thedose to OARs posterior to the PTV in both prostate and oropharynx plans.
As expected, the MU delivery errors shifted the OAR DVHs along the dose
axis but had no effect on the shape of the curve. MLC offsets as small as
1.5 mm reduced the fraction of the PTV receiving 95% of the prescribed doseto less than 99% leading to a TCP reduction of 0.5%. This error was notdetected with a gamma threshold greater than 3%/2mm or 2%/3mm. The 4%

Results: We observed a very low intrinsic dispersion, dominated by Poisson
statistics, for both xc (standard deviations of less than 1 mm) and int (standard
deviations of less than 0.25 %). When confronted with random leaf positioning errors from IMRT segments, int was highly sensitive to single errors as
small as 1 mm at isocenter, while xc was sensitive to leaf pair translation errors of at least 2 mm at isocenter. The fluence monitor achieved a uniform
beam transmission of 98.3%. Changes in percent depth-dose and relative
dose profiles of square beams were found to be within 1%.
Conclusions: Our study showed that an optical attenuationbased detector
could be used to effectively monitor fluence during radiotherapy delivery. The
performance of such a system would enable real-time quality control of theincident fluence in current MLC-driven treatments such as IMRT and future

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adaptive radiotherapy procedures where new treatment plans will have to bedelivered without passing thru the current standard quality control chain.
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AN INDEPENDENT DOSE CALCULATION PROGRAM FOR THE
CHECKING OF TOMOTHERAPY PLANS
S. Thomas1 , K. Eyre1 , S. Tudor1 , J. Fairfoul1
1
A DDENBROOKE ’ S H OSPITAL, Medical Physics, Cambridge, United Kingdom
Purpose: It is usual practice for all patients being treated on Tomotherapy tohave individual delivery quality assurance (DQA) measurements to verify thedose delivered to a phantom. A major reason why it has not possible to relax
this requirement has been the lack of an independent means of calculating
the dose distribution. We have developed an independent calculation system
which takes the patient-specific files from the TomoTherapy planning system
and applies it to the patient CT data set in three dimensions.
Materials: Beam data was measured to provide output factors, tissue phantom ratios, longitudinal beam profiles and in-plane beam profiles. They were
measured on a TomoTherapy Hi-Art using A1SL chambers in a water tank.
The HiArt delivers radiotherapy by rotating a beam around the patient whilst
moving the couch longitudinally. The fluence is modulated with a set of binary
collimators. The fluence pattern for each of 51 gantry positions, for each rotation, is saved in a sinogram file. The planning system also saves an XML file,that contains information such as the field width (defined in the direction ofcouch motion), the pitch, the speed of gantry rotation, the gantry start angle
and the patient position at the start of irradiation. Each projection in the sinogram can be modelled as a set of segments. A program was written in Matlab
to calculate the dose by interpolating into the measured beam data for eachsegment. The radiological path length for each calculation point is calculated
by projecting through the CT images. Dose is calculated at 3375 calculation
points, and compared with the doses in the DICOM dose cube exported by
the Tomotherapy planning system.
Results: The system was tested on a range of prostate and prostate+nodes
plans. Calculation times range from 1.1 to 4.7 minutes, depending on thecomplexity of the sinogram. Averaged over all points within the 50% isodose surface, the mean dose difference between the two sets of calculated
doses ranged from -1.3% to +0.6% for prostate plans, -0.3% to +2.4% forprosate+nodes plans. The Gamma index was used to compare dose distributions. A 4mm/4% Gamma index gave between 93% and 98% of points
within the 50% isodose surface achieving Gamma<1 for prostate patients.
Figure 1 shows a typical Gamma histogram. The Kappa and Box indices canbe used as alternatives to Gamma. Simulating moves of 2% and 2mm causes
the percentage passing to fall by 8-10%, demonstrating the use of the system
in detecting simulated errors.
Conclusions: Having a fast means of independently checking the dose distribution provides a useful additional safeguard against errors. The use ofbeam data derived from measurement ensures independence from the planning system. The system achieves a level of accuracy sufficient to serve asa means of detecting errors in the plan. We are currently undergoing final
testing and evaluation of the system, prior to a decision of whether to reduce
the frequency of DQA measurements.

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INITIAL EXPERIENCE WITH A NOVEL ON-LINE BEAM MONITORINGSYSTEM
M. Islam1 , B. Norrlinger1 , D. Jaffray1 , G. Wilson1 , Y. Wang1 , R. Heaton1
1
P RINCESS M ARGARET H OSPITAL, Department of Radiation Physics,
Toronto, Canada
Purpose: To explore the feasibility and effectiveness of an independent beam
monitoring system for routine validation of treatment beam delivery.
Materials: An on-line independent beam monitoring system, consisting of a
spatially sensitive large area ionization chamber mounted after the MLC, anelectrometer, and a calculation algorithm to predict the signal for each beam
segment, has been developed for routine clinical use. The system, termed
Integral Quality Monitor (IQM), utilizes a simple spatially dependent checksum for each beam segment to validate the treatment delivery. The treatment is validated by comparing pre-calculated signals with those measured
on-line. In the case of Volumetric Modulated Arc Therapy (VMAT) the IQM
software captures gantry angle information independently from an inclinometer mounted on the gantry. In preparation for clinical implementation of IQM
we have used the device during simulated patient treatments on an Elekta
Synergy®linear accelerator involving Radiation Therapists, the purpose ofwhich was to determine IQM’s impact on workflow. The system has also beenused to monitor beam delivery during physics QA of more than 100 IMRTand VMAT plans. The system’s performance has been evaluated in termsof reproducibility, calculated signals versus measured, and error detectability. To examine the uniqueness of the IQM checksum for each segmented
treatment field we have compared the measured signals from 50 prostate patients’ plans. The uniqueness of each treatment field has been evaluated by
calculating a Similarity Index (SI). Two fields are considered to have 100% SI
if two conditions are met: (1) they have the same number of segments and(2) if the checksums from corresponding segments of both fields agree withina certain tolerance (e.g. 5%).
Results: The results of the patient treatment simulation demonstrated thatthe use of IQM has minimal impact on workflow. IQM is fully automated,
requiring only the installation and removal of the ion chamber as needed.
The system’s response was reproducible to within 0.4%. The agreement between the calculation and measured signals for prostate IMRT field segments
were within 1% on average, with a maximum deviation of 5%. The system’s
response for a small geometrical segment changed by 2% for a leaf bank calibration error of 1 mm or a single leaf positioning error of 3 mm. Using the SI,
no two fields were found to be similar.
Conclusions: A novel on-line beam monitoring system has been developed
and validated for clinical use. The system has been shown to be capableof capturing common errors while validating beam delivery with minimal impact on workflow. As an on-line beam delivery monitor, the system has thepotential to improve quality and patient safety in radiation therapy.
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TOWARDS AUTOMATIC QUALITY ASSURANCE (QA) OF VOLUMETRIC MODULATED ARC THERAPY (VMAT)
R. Ruchaud1 , C. Rodrigues1 , D. Gibon2 , L. Massoptier2
1
P RIVATE R ADIOTHERAPY C ENTER OF M ETZ, Metz, France
2
AQUILAB SAS, Lille, France
Purpose: Volumetric Modulated Arc Therapy (VMAT) delivery systems combine multi-leaf collimator (MLC), gantry and dose-rate modulation for dose
conformation purposes. We developed test patterns and algorithms to automatically evaluate: leaf positions, speed and dragging effects. The techniques implemented rely on images produced by an Electronic Portal Imaging
System (EPID) and they correct inherent images deformations.
Materials: VMAT delivery with a Beam Modulator Synergy (ELEKTA, Crawley, UK) was evaluated by analyzing the EPID images generated by 4 test
patterns. Processing was done on the development platform of the ARTISCAN software (AQUILAB SAS, Lille, France).Leaf speed effects on position
accuracy during gantry rotation were evaluated, including detection accuracy(by simulating MLC leaf position errors of 0.5, 1, 2 and 5 mm). Six picket fence
images were required using a single-arc for three dose rates (150, 300, 600
MU/min) and two collimator angles (0◦ , 90◦ ). Constant leaf movements werechecked by processing the image generated by sweeping a 1-cm slit continuously during a single-arc. Six images were required with combinations of
three dose rates (150, 300, 600 MU/min) and two collimator angles (0◦ , 90◦ ).
Leaf dragging effects were investigated by using Sin and Chi2 functions asleaf speed relations in the same conditions as above.All the mentioned tests
are based on automatic detection of inter-leaf positions and leaf border localization. Contrast enhancement, gradient-based peak filtering and mathematical morphology techniques are combined for this purpose. Deformation
corrected profiles of each leaf trajectories were extracted and analyzed independently to compute each parameter. Average and width of irradiated areas
were computed and compared with leafs on the same bank.
Results: Inter-leaf positions and leaf borders were automatically detected,
free of image distortions, by the developed algorithm using 360◦ EPID image acquisitions. For leaf position and speed tests, defective leafs could be

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spotted whenever one of its parameter p didn’t belong to the range [µp-3σ p;µp+3σ p] (where µp and σ p are, respectively, the average and the standard

deviation of parameter p). In addition, all simulated MLC errors were correctly detected by the automatic algorithm with no false positive.For the leaf
dragging effects theoretical Sin and Chi2 functions were correlated to the distribution of average intensities on leaf profiles and no dragging effect could
be observed on our linear accelerator.
Conclusions: The developed algorithms show reliability for automatic QA of
linear accelerators in VMAT mode.
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INVESTIGATION OF DIFFERENT PIXEL DETECTORS FOR LASERDRIVEN ACCELERATED PARTICLE BEAMS
S. Reinhardt1 , W. Assmann1 , C. Granja2 , J. Jakubek2 , P. Kneschaurek3 , F.
Krejci2 , J. Wilkens3
1
L UDWIG -M AXIMILIANS -U NIVERSITY, Fakultät für Physik, Munich, Germany
2
C ZECH T ECHNICAL U NIVERSITY OF P RAGUE, Institute of Experimental andApplied Physics, Prague, Czech Republic
3
TU M ÜNCHEN, Klinikum rechts der Isar, München, Germany
Purpose: p { margin-bottom: 0.08in; }One of the main goals of the Munich
Centre for Advanced Photonics (MAP) is the use of laser driven accelerated(LDA) particle beams for radiation therapy. Due to the unique acceleration
process ultrashort particle pulses of high intensity (> 107 particles/cm2 /ns)
are generated, which makes online detection an ambitious task. So far, thestate of the art in detection of laser accelerated ion pulses are non-electronic
detectors like radiochromic films (RCF), imaging plates (IP) or nuclear track
detectors (e.g. CR39). All these kind of detectors are offline detectors requiring several hours of processing time. For this reason they are not qualified
for an application in radiation therapy where quantitative real time monitoringof the beam is an essential prerequisite. p { margin-bottom: 0.08in; }Therefore we are investigating pixel detectors for real time detection of LDA particle
pulses. As each pixel represents a small detector unit in itself, only a small
fraction of the whole LDA beam will be detected by each pixel and so problems due to detector saturation might be overcome by this new approach.
Due to excellent spatial resolution of pixel detectors additional information
about the spatial fluence distribution is obtained.
Materials: p { margin-bottom: 0.08in; }Response of different types of pixel
detectors has been tested in a 820 MeV proton beam from an electrostatic
accelerator for different beam conditions (single ion, dc, pulsed beam).Two of
the used systems are commercially available, one based on a digital camera
CCD-chip (7.4 micron x 7.4 micron pixel size, 106 pixels) and the other on a
CMOS photodiode array in a matrix of 512 x 1024 pixels with 48 micron pitch.
Both sensors are optimized for detection of visible light, featuring a depletion depth of 2-3 microns.The third investigated system is a non commercial
system, developed in the framework of the Medipix collaboration. It is basedon the Medipix2 read-out chip containing 256 x 256 pixels with a pitch of 55
micron, bump-bonded to a 300 micron Si-detector chip.
Results: p { margin-bottom: 0.08in; }All systems show good linearity between
integrated detector signal and particle fluence. Furthermore single protons
can be detected with all systems. Placing the detectors under a grazing angle
with respect to the beam direction, we were able to measure the track lengthand Bragg curve of the incident protons.
Conclusions: p { margin-bottom: 0.08in; }The performance of all tested devices is promising with respect to the saturation level. Nevertheless, in caseof the two systems optimized for optical detection, energy resolution is limited
due to the fact that energy loss and energy loss straggling are of the sameorder of magnitude. However pixel detectors are promising candidates formonitoring the spatial dose distribution for future application of a LDA beams
in radiation therapy.

W EDNESDAY, M AY 11, 2011

PosterYoung scientists ESTRO Poster Session: Trial design and data analysis
391 poster
DESIGNING A MULTI-CENTER DOSE-PAINTING TRIAL: METHODOLOGY AND PITFALLS
W. van Elmpt1 , E. Damen2 , M. Öllers1 , J. J. Sonke2 , J. Belderbos2 , D. De
Ruysscher1
D EPARTMENT OF R ADIATION O NCOLOGY (MAASTRO), GROW - S CHOOLFOR O NCOLOGY AND D EVELOPMENTAL B IOLOGY, M AASTRICHT U NIVERSITYM EDICAL C ENTER, Maastricht, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

1

Purpose: Intensity modulated radiotherapy has reached a status that is sufficient to test dose-painting (DP) in clinical trials, such as for head-and-neckand lung cancer. Both dose-painting by numbers (DPBN) or by dose painting
by contours/volumes (DPBC) are hypothesized to individualize the treatmentof cancer patients to provide the most optimal treatment. We will discuss themethodology and possible pitfalls for designing DP trials and use our currently
ongoing multi-center randomised phase II PET-boost trial as an example.
Materials: Our multi-center DPBC trial for stage II-III non-small cell lung cancer patients (PET-boost trial: NCT 01024829) recently started. We hypothesised that DPBC based on pre-radiotherapy PET imaging improves local
control of the primary tumour. The following criteria were taken into accountin the design of this DP trial: 1) Forcing iso-toxicity is mandatory to provethat DP is superior compared to homogeneous dose delivery without the biasof more toxicity and/or more integral target dose in the experimental arm; 2)Standardization of the imaging techniques is of utmost importance as well as3) standardized delineation of organs-at-risk (OAR) and 4) treatment planningtechniques and delivery should be comparable in all centers.
Results: We designed a randomized phase II trial on dose-escalation ofadvanced NSCLC patients to the primary tumour. A two-arm randomized
design was chosen. Arm A: homogeneous boost to the entire primary tumour target volume. Arm B: boost to the high FDG-uptake region (SUV
max>50%) within the primary tumour without decreasing the minimal PTV
dose below our current standard (66 Gy/ 24 fractions). 1) Both arms A
and B are normalized, i.e. forced isotoxic for the mean lung dose (MLD) toeach other by performing dual arm treatment planning for every patient andforcing a downscaling of the treatment plan with the highest MLD towards
equal MLD of the other arm. 2) The FDG-PET imaging is standardized using the NEDPAS protocol (Boellaard et al. 2009) for all PET scanners usedin the participating centres. 3) An atlas was created (freely downloadable at
http://www.maastro.nl/web/show/id=62542/langid=432 ) and is used to standardize delineations of the OARs. 4) A feasibility treatment planning study
prior to start of the trial was performed to assure that the dose-escalationlevels for identical patients were similar.
Conclusions: Designing a dose-painting trial is not trivial. Unbalanced or
single arm studies will be biased against the fact that the integral dose insuch DP trials is higher, hence leading to improved local control, thus not investigating dose redistribution in the PTV but also dose-escalation. A control
arm with approximately equal toxicity and preferably also equal integral doseto the target structures might provide solid evidence that DP has an added
value towards treatment outcome.
392 poster
INTERNATIONAL IMRT CREDENTIALING BY PHYSICAL PHANTOMIRRADIATION: THE EORTC ROG EXPERIENCE
A. Fairchild1 , A. Gulyban2 , J. M. Denis3 , S. Vynckier3 , N. Hernandez4 ,A. Molineu4 , D. Followill4 , P. Fenton1 , D. C. Weber15 , C. Hurkmans16 , V.
Grégoire13
1
EORTC, Brussels, Belgium
2
UZ-B RUSSEL, Brussel, Belgium
3
UCL C LINIQUES U NIV. S T.L UC, Brussels, Belgium
4
R ADIOLOGICAL P HYSICS C ENTER, Houston, USA
5
H ÔPITAL C ANTONAL U NIV. G ENÈVE, Geneva 14, Switzerland
6
C ATHARINA Z IEKENHUIS, Eindhoven, Netherlands
Purpose: For credentialing of an international IMRT head and neck cancer trial, three identical anthropomorphic head phantoms were obtained froman external dosimetry laboratory (EDL). The phantom’s insert contains eight
TLDs marking primary and secondary PTVs and one organ at risk (OAR;
Figure 1). GAFchromic dosimetry film is placed through the primary PTV in
the axial and sagittal planes and steel needles act as fiducial markers. Our
objective was to investigate the timeliness, reproducibility and accuracy of
reloading the insert independent of the EDL.
2 http://www.maastro.nl/web/show/id=62542/langid=43

P OSTERS 155

Materials: Four sequential CT simulation scans were performed; between
each, the insert was completely disassembled, reassembled (TLD, film), andthe scans were co-registered. KV-CT doses were separately extracted fromTLD doses based on EDL procedures. Following the final scan, the insert
was left intact; volumes were delineated and an IMRT plan created with thefollowing dosimetric objectives: primary and secondary PTVs should receive
6.6Gy and 5.4Gy respectively, and maximum allowed dose to the OAR is
4.5Gy. The phantom was irradiated with this plan three times, with the insert
reloaded each time. The fourth and final irradiation was to enable extractionof dose contributed by position verification (MV-CT).
Results: On average, it took 15-20 minutes to reload the dosimetry insert,
which moved <2mm between CT acqusitions. The degree of exposure of
GAFchromic film was not different from background compared to KV-CT. MVCT dose based on TLD evaluation was <0.01Gy. For the three irradiations,the average ratio between the actual dose delivered to the primary PTV (measured by TLD exposure at the EDL) and dose prospectively planned was 0.96,
0.96 and 0.95 (acceptable range 0.93-1.07). Values for the secondary PTV
were 0.95, 0.96 and 0.95. Film dose maps confirmed concordance (<0.5mm
displacement) of the calculated and observed dose gradient in the region between the primary PTV and the OAR for each irradiation.
Conclusions: This confirms both the feasibility and equivalent accuracy of
reloading of the dosimetry insert independent of the EDL, permitting parallel
phantom irradiation via site visits for IMRT credentialing. To date, this has
been completed in 14 institutions (seven each via site visits and direct shipment of phantoms from the EDL to participating institutions).

Figure 1. Cross-sectional view of the insert in the axial film plane as found in
irradiation instructions of the EDL.
393 poster
AD-HOC DATA SHARING INFRASTRUCTURE FOR RADIOTHERAPYRESEARCH COLLABORATION: A TOOL FOR MULTICENTRIC
CLINICAL RESEARCH
A. Dekker1 , E. Roelofs1 , E. Meldolesi2 , V. Valentini2 , P. Lambin1
1
M AASTRICHT R ADIATION O NCOLOGY (MAASTRO), GROW - S CHOOLFOR O NCOLOGY AND D EVELOPMENTAL B IOLOGY, U NIVERSITY M AASTRICHT ,Maastricht, Netherlands
2
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Roma, Italy
Purpose: Extensive multifactorial data sharing is widely recognized as crucial for current and future radiotherapy research, clinical research in general,but the cost, time and effort it takes to share data is often a roadblock. The
purpose of this work is to present a quick, ad-hoc data sharing infrastructure between two radiotherapy departments based on free or open source
products.
Materials: A collaboration and data transfer agreement was signed which
describes the type of data, the permitted use and the protection of the data.
This agreement was submitted to and approved by the local ethical authority.
On a research workstation (Windows XP 32-bit, Intel Xeon, 2.53GHz, 4GBRAM) the following software was installed: SQL Server 2008 (free Express
version, Microsoft, Redmond, WA); Clear Canvas Image Server and Workstation (both free and open source, Clear Canvas, Toronto, Canada); DCMTKDICOM toolkit (free and open source, Offis, Oldenburg, Germany); RSNA
Clinical Trial Processor CTP (free and open source, RSNA, Oakbrook, IL) andMatlab Runtime Component (free, Mathworks, Natick, MA). Nightly text andDICOM synchronization with the local clinical databases was implemented.
Part of the synchronization mechanism is an extensive de-identification andthe translation of local terms to a standardized terminology (SNOMED).

S 156

P OSTERW EDNESDAY, M AY 11, 2011
Where seroma was clearly visible, the KCL was high for all observers, regardless of experience or training. However, in the cases with less visible
seroma, the experts’ experience in defining the tumour bed to cavity interface based on clips and architectural distortion was demonstrated in higher
KCLs than for their less experienced junior colleagues. For cases with lessvisible seroma, the use of the training protocol improved conformity amongst
the less experienced observers.
Conclusions: Conformity in CTV delineation amongst experienced IMPORTLow study triallists is satisfactory, and use of a training protocol improves conformity in target volume delineation amongst inexperienced clinicians. Conformity is lower for all observers, regardless of experience, where seroma isless visible.
395 poster

Results: The data sharing infrastructure was implemented in two months(July-August 2010). As of November 2010, the ResearchDB holds about1100 lung and 1200 rectum cancer patients and the ResearchPACS holds
about 5.000 de-identified DICOM objects using a total of 1 TB storage. All
new rectum and lung cancer patients are added automatically to the ResearchDB and PACS through the nightly synchronization, with a projected
yearly increase of approximately 150 lung and 70 rectum patients. The infrastructure is actively used in the Thunder trial (NCT00969657) in which multiple
PET/CT scans before after and during concurrent chemo-radiation are used
to predict the likelihood of a complete pathological response in rectum cancer
patients. A second IRB approved trial using the infrastructure will be the "Radiomics in NSCLC" trial (NIH U01-CA143062-02) in which advanced analysis
of CT and PET images of lung cancer patients are correlated with genetic
expression and outcome.
Conclusions: We have described one way to build a data sharing infrastructure quickly and at low cost, which makes sharing of data easier between two
institutes wishing to work together. Starting with contractual arrangements on
the use and protection of the data, it is possible to build a data infrastructurethat uses either free or open source products and that can address common
problems such as data de-identification, the need to share DICOM RT objects
and the need for a common language/ontology
394 poster
IMPORT-LOW PARTIAL BREAST OUTLINING STUDY: USE OF A
TRAINING PROTOCOL TO IMPROVE INTER-OBSERVER CONCORDANCE
A. Kirby1 , R. Jena2 , Y. Tsang3 , L. Ciurlionis3 , E. Harris4 , J. R. Yarnold5 , C.
Coles2
1
R OYAL M ARSDEN H OSPITAL, Radiotherapy, London, United Kingdom
2
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Radiotherapy, Cambridge, United Kingdom
3
M OUNT V ERNON H OSPITAL, Physics, Northwood Middlesex, United
Kingdom
4
I NSTITUTE OF C ANCER R ESEARCH, Physics, Sutton, United Kingdom
5
I NSTITUTE OF C ANCER R ESEARCH, Radiotherapy, Sutton, United Kingdom
Purpose: Delineation of partial breast volumes is associated with significant
interobserver variability (IOV). IOV can be reduced by use of guidelines suchas those provided for all investigators in the NCRI IMPORT-Low partial breast
irradiation study. We aimed to test 1) the degree of concordance between
experienced triallists, and 2) whether or not the IMPORT-Low training protocol
improved accuracy in target volume localisation amongst previously untrained
clinicians.
Materials: Three IMPORT-Low cases with six tumor bed (TB) clips in-situ,
and with discrete seroma (case 1), minimal seroma (case 2) and no seroma(case 3) respectively, were selected and anonymised. Sixteen principal investigators (PI) from centres participating in the IMPORT-Low study eachoutlined TB, clinical target volume (CTV) and planning target volume (PTV)
on each case. Sixteen untrained specialist registrars (SpR) from the same
centres were also asked to outline TB, CTV, and PTV, both before and after training according to the IMPORT-Low protocol. Datasets were analysedusing SHERRI (Surrey Heuristics Engine for Radiobiology, Radiotherapy andImaging) (a suite of software tools for assessment of contours (morphometrics)). For each of the three cohorts (experts, SpR pre-training, and SpR
post-training), the Kouwenhoven Conformity Level (KCL) for the CTV was
calculated.
Results:

A REVIEW OF IMRT CREDENTIALING FOR CLINICAL TRIALS IN
THE UKL. Ciurlionis1 , Y. M. Tsang1 , E. Miles1 , O. Naismith2 , C. Clark3 , E. Wells2 ,E. Aird4
1
M OUNT V ERNON H OSPITAL, Radiotherapy Physics, Northwood Middlesex,
United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiotherapy Physics,
London, United Kingdom
3
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, Radiotherapy Physics, Guildford, United Kingdom
4
M OUNT V ERNON H OSPITAL, Medical Physics, Northwood Middlesex,
United Kingdom
Purpose: The National Radiotherapy Trials Quality Assurance group (RTTQA) is supported by the NCRI (National Cancer Research Institute) andwas established to coordinate the work of clinical trial QA teams in the UK.
In recent years the group has developed and coordinated the QA for 4 IMRT
trials (CHHiP, PARSPORT, COSTAR and IMPORT HIGH), which has so far
involved 15 centres. The aim was to provide a credentialing program which
would cover clinical and dosimetry audit for each centre and be appropriate
to anatomical site. The long term goal is to standardise procedures across all
IMRT trials.
Materials: The programme provides a full IMRT audit from commissioning, delineation and planning through to QA measurements. It consists ofnine modules covering outlining, planning, treatment planning system (TPS)
checks, fluence and dose distribution verification, point dose verification andalso includes a questionnaire and the requirement to develop a process document for each centre. A further benefit of bringing these centres together isthe determination of acceptable tolerance values for IMRT QA for clinical trials. The RTTQA group is also developing audits which include credentialing
for advanced techniques such as VMAT (volumetric modulated arc therapy).
Results: 15 out of 60 UK radiotherapy centres have undergone the full IMRT
credentialing programme for clinical trials and several others are in the process of completing. Dose points measured in the primary and secondary
target volumes for head and neck and prostate plans were within 2.4% and2.7% respectively of the prescribed doses, all passing the initial tolerance
value of 3%. For combined field film dosimetry, 84% of films passed with agamma tolerance parameter of greater than 95% at the 4%/4mm level with
a 20% threshold. The films with measurements outside the initial tolerance
values were from 2 centres. These were found to be mainly due to the use of
a dose grid greater than that recommended, and complexity of planning anddelivery for some plans. All issues were resolved after discussion with thetrial centres.
Conclusions: This review of data from the credentialing programme has provided confidence that UK centres are able to deliver IMRT treatment with ahigh level of conformity to clinical trial protocols. It is allowing us to determine
site specific tolerances which can be applied in a range of trials, and we arealso interacting with the relevant national bodies such as the National Cancer Action Team to define equivalent IMRT QA standards for routine clinicalpractice.
396 poster
STRUCTURING THE DATA-BASE OF A MULTICENTRIC STUDYTO EVALUATE PREDICTORS OF GU AND SEXUAL TOXICITY IN
PROSTATE RT
E. Maggiulli1 , C. Cozzarini2 , A. Deli2 , M. La Macchia3 , G. Fellin4 , L. Perna1 ,T. Rancati5 , V. Vavassori6 , S. Villa7 , R. Valdagni5 , C. Fiorino1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Radiotherapy, Milan, Italy
3
AT RE P, AGENZIA P ROVINCIALE PER LA P ROTONTERAPIA, Radiotherapy,
Trento, Italy
4
O SPEDALE S ANTA C HIARA, Radiotherapy, Trento, Italy
5
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Prostate
Program, Milan, Italy
6
C LINICHE G AVAZZENI, Radiotherapy, Bergamo, Italy
7
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Radiotherapy,
Milan, Italy
1

W EDNESDAY, M AY 11, 2011

Purpose: In spite of the advances in radiotherapy treatment modalities, acuteand late toxicity remains an issue of paramount importance in the evaluation of the clinical benefit of radical external radiation (ERT) for prostate cancer.Literature data on clinical and dosimetric factors potentially affecting therisk of genito-urinary (GU) toxicity and erectile dysfunction (ED) after ERT
are scarce and controversial.In April 2010, a prospective multicenter observational trial (Disfunzione Urinaria Erettile, DUE-01) was activated aiming at
developing quantitative predictive models of GU toxicity and ED. Up to now,
fifteen centers are participating, with San Raffaele Institute (HSR), as the coordinating group. 500 patients are expected to be enrolled in two years.
Materials: Main inclusion criteria are as follows: age<80 yrs; baseline IIEF
questionnaire score ≥13 (in erectile domain and for ED sub trial only); irrelevant value of the basal IPSS score (in GU sub trial); RT doses ≥ 70Gy.The
methodology of the study includes an informative questionnaire filled before
therapy on clinical patient data: age, body-mass-index, concomitant comorbidities (diabetes, hypertension), previous pelvic/abdominal surgery, use ofdrugs, dietary habits, T staging, type and duration of neo-adjuvant hormonal
therapy, testosterone levels, technical and dose-volume data (dose; fractionation; volumes; irradiation technique; dose statistics for PTVs, bladderand penile bulb). Four questionnaires on QoL, GU and erectile disfunctions(QLQ-C30, IPSS, ICIQ-SF, IIEF) are given to the patients before, at the endof ERT and every 6 mos up to 5 yrs post-treatment.Dosimetric data (DVH,
images/contours, 3D dose maps) will be recorded and analyzed with a dedicated research program (Vodca Software, MSS GmbH, Zurich).
Results: Up to now (December 2010), 37 patients have been enrolled in 5
Institutes. The other institutes are expected to start enrollment once the trial
is approved by ethical committees. The structure of the database has beencreated in Vodca; clinical and dosimetric data regarding 22 patients wereentered in the database. Procedures for monitoring the sending of the data
to the coordinator centre are being finalized. An external platform to facilitate
the uploading of dosimetric data is under testing as well as compatibility forthe different treatment planning systems used within the group of Institutes
involved.
Conclusions: The DUE-01 study started this year with the aim of better
assessing predictors of late GU toxicity and sexual dysfunction after highdose Radiotherapy of prostate cancer. Procedures for properly structuring
the database and the uploading of data have been activated using a research
dedicated program. The study is supported by a grant from the Associazione
Italiana Ricerca sul Cancro (AIRC-IG8748)
397 poster
EXTENSIONS OF CERR FOR COMPARATIVE COHORT EVALUATIONS
A. Apte1 , J. O. Deasy1
1

M EMORIAL S LOAN -K ETTERING C ANCER C ENTER, Medical Physics, New
York, USA
Purpose: Treatment outcomes across patient cohorts may obviously dependon differences in treatment plans, imaging, and anatomic contouring, yet software tools that facilitate the side-by-side review of patient data cohorts areunavailable. The purpose of this effort was to extend a set of existing tools
to provide a convenient system to access, review and evaluate patient cohorts in a side-by-side fashion, integrated with a system for extracting data
for statistical modeling.
Materials: This work builds on the existing open-source frameworks of CERR
[1] (The Computational Environment for Radiotherapy Research) and DREES[2] (The Dose Response Explorer System) to provide (1) a graphical environment for side-by-side review of a cohort of patients, (2) convenient reconciliation of variable names for the same structures, (3) extraction of dose volume
parameters and/or user-coded metrics, (4) statistical modeling on the derived
cohort, and (5) storage of data extracted from the selected cohort as native
Matlab, Excel, or sql database objects.
Results: Figure shows graphical interface for the software. The user canreview the selected structure for the entire cohort in batches of 16 patientsat once. An example is shown for a cohort of rectum contours for prostatecancer patients. This tool is integrated with other CERR and DREES tools
to conveniently facilitate review and extraction of treatment planning data as
well as statistical outcomes modeling. The entire system has recently been
GNU-copyright using the lesser-GNU license.

P OSTER

S 157

Conclusions: This extension of CERR and DREES provides a powerful platform to create and validate outcomes models and inter-institutional datasets.
The tool provides a convenient method for reviewing and comparing structures, images, and treatment plan dose distributions for cohorts of patients.
This research was partially supported by NIH R01 grant 85181 References[1]J.O. Deasy, et al, CERR: A computational environment for radiotherapy research, Med Phys 30, pp. 979985, 2003.[2] El Naqa I et al, Dose response
explorer: an integrated open-source tool for exploring and modeling radiotherapy dose-volume outcome relationships Phys. Med. Biol. 51, pp. 5719-35,
2006.

Young scientists ESTRO Poster Session: Treatment planning studies
398 poster
PHOTON ARC AND PROTON THERAPY PLANNING COMPARISONFOR HIGH GRADE GLIOMA BASED ON CT, FDG-PET AND DTI-MRIAND FIBER-TRACKING
P. Munck af Rosenschöld1 , S. Spahn-Horn1 , L. Ohlhues1 , S. A. Engelholm1
1
T HE F INSEN C ENTER - R IGSHOSPITALET, Radiation Oncology, Copenhagen, Denmark
Purpose: The purpose of this study was to compare treatment plans generated using fixed beam Intensity Modulated Radiation Therapy (IMRT), inversely optimized arc therapy (RapidArc®, RA) with spot-scanned Intensity
Modulated Proton Therapy (IMPT) for high-grade glioma. Plans were compared with respect to target coverage and sparing of organs at risk (OARs).
Materials: Fifteen consecutive patients diagnosed with glioma grades III andIV were selected. The target and organs at risks were delineated based on
CT, FDG-PET and T1, T2, Diffusion Tensor Imaging (DTI) MRI and fibertracking (BrainLab). A 6 MV photon beam with a high-definition MLC machine(NovalisTx) and the PT2 proton therapy machine were used, implemented
in the Eclipse (v8.6) treatment planning system (Varian Medical Systems,
US). Two RapidArc fields using both a coplanar (clinical standard) and a noncoplanar setup was attempted. Three and three to four non-coplanar fields
where used in the spot-scanned IMPT and IMRT plans, respectively. The
same set of planning objectives (i.e. priorities) were used for the four techniques. The highest planning priority was given to the brainstem (max 54 Gy)
followed by the PTV (prescription 60 Gy); the hippocampuses, eyes, opticalfibers and chiasm were given lower priority. Doses were recorded for theplans to targets and OARs and compared to our clinical standard techniqueusing the Wilcoxon signed rank test.
Results: The mean doses to the eyes were significantly lower for both the
IMRT (2.1 Gy) and IMPT (0.2 Gy) plans compared to the standard (3.9 Gy),
which was achieved using carefully selected beam directions. The maximum
doses to the chiasm and brainstem were comparable for all techniques. The
PTV coverage was most conform for IMPT, followed by the RA and then the
IMRT technique (see Figure 1). In case of a tumor located in a temporal lobe
(8 patients), the non-coplanar RA and IMPT techniques yielded a significantly
lower dose to the contralateral hippocampus compared to the standard (22%and 97% average reduction for RA and IMPT, respectively). The IMPT technique allowed for the largest healthy tissue sparing of the techniques in termsof whole brain doses.
Conclusions: For tumors in the temporal lobe, the non-coplanar RA and the
IMPT techniques were able to reduce doses to the contralateral hippocampus. RA techniques produced more conform target doses than IMRT at thecost of slightly elevated doses to the eyes.

S 158P OSTERW EDNESDAY, M AY 11, 2011

W EDNESDAY, M AY 11, 2011
fluence with a suitable kernel. Second, that a transformation (T) kernel exists,such that the DD in the presence of a MF can be described by a convolutionof a DD without MF and a T kernel K0B (r). This kernel can be derived fromthe point-spread kernels with and without MF, K0(r) and KB(r), respectively, asBr )]−1 F3 [KB (K0 (r ) = F3F3 [K0 (r )]-1

400 poster

Figure 1. Cumulative dose volume histogram for the PTV averaged for all
patients for IMRT, IMPT and the RA techniques.

IMPACT OF BREAST SHAPE CHANGES ON VMAT: A SUGGESTEDPLAN STRATEGY
G. Nicolini1 , A. Fogliata1 , A. Clivio1 , E. Vanetti de Palma1 , L. Cozzi1
1, where F3 and F3 denote the 3D Fourier transform and its inverse.The
method was tested on MC DDs in a 10x10cm water phantom using Geant4,
for both monoenergetic beams and one having a 6MV linac spectrum. A MC
DD was transformed into a DD with MF of 1.5T and 3T and the result wascompared with MC DDs incorporating a MF.
Results: In first calculations, both position and shape of the shoulders of thecross profiles generated by the T agreed with the MC-simulated DD (cf.fig.).
In the high dose area, local deviations were around 5% for the monoenergetic case and around 10% for the spectral case; however, the fluctuationsin the MC simulations used were of the same magnitude such that it is anticipated that this error reduces when using MCs with better statistics and/or
smoothing.As expected, large differences were observed at the exit surfaceof the beam from the water phantom, since the T does not model the electron
return effect in air.

IOSI, Medical Physics Unit - RadioOncology Dept, Bellinzona, Switzerland

399 poster
ISOTOXIC DOSE-ESCALATION IN NSCLC RADIOTHERAPY: TARGET DOSE COVERAGE AS A FUNCTION OF DOSE-CALCULATIONALGORITHM, MULTILEAF PENUMBRA MARGIN, AND BREATHING
MOTION.
V. Panettieri1 2 , J. Fenwick2 3 , Z. Malik4 , D. Landau5 , P. Mayles2 , A. E.
Nahum2 , P. Jain4
1
W ILLIAM B UCKLAND R ADIOTHERAPY C ENTRE, Department of Physics,
Melbourne, Australia
2
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Department of Physics,
Bebington, Merseyside, United Kingdom
3
S CHOOL OF C ANCER S TUDIES, Liverpool, United Kingdom
4
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Radiotherapy, Bebington,
Merseyside, United Kingdom
5
G UY ’ S AND S T. T HOMAS ’ NHS F OUNDATION T RUST, Department ofRadiotherapy, London, United Kingdom
Purpose: Several institutions are using isotoxic dose-escalation schedules
for the treatment of non small-cell lung cancer.Among these, the IDEAL-CRT
phase I/II clinical trial was initiated in the UK in order to treat patients withan individualised prescription dose (ranging from 63 to 73 Gy in 30# combined with a chemotherapy regime) calculated according to the relative mean
normalised total dose (rNTDmean), a metric related to lung toxicity.Since thistrial is being conducted in various centres using different treatment planningsystems (TPS), a study was performed to look at differences in the calculated target dose coverage.Additionally the use of different multileaf (MLC)
penumbra margins was analysed in order to maximise dose-escalation, andthe study was extended to account for breathing motion using the 4D-dose
accumulation tool in the Research Interface of the Pinnacle TPS.
Materials: Seventeen lung patients, ten scanned with a 3D-CT and sevenwith a 4D-CT protocol, and planned with a standard 7 mm MLC penumbra
margin, were initially planned using the Pinnacle Collapsed Cone Convolution(CCC) algorithm. The plans were recalculated with the pencil beam convolution (PBC) and AAA algorithms of the Eclipse TPS with the same prescriptiondose, and the PTV, V95 and V90 were compared. Using the IDEAL-CRT protocol [1], prescription doses were then calculated with CCC and AAA for MLC
penumbra margins of 3 to 10 mm, in order to identify the margin size which
maximised the PTV minimum target dose-level (D99) according to the rNTDmean value. The same study was also carried out for a further 4 patients,
taking into account respiratory motion by calculating doses accumulated on
different breathing phases using Research Pinnacle.
Results: For a 7 mm multileaf margin and for all the patients studied, a PTV
V95 of 98-99% using the PBC algorithm corresponds to a V95 of at least 90%
and a V90 of 98-99% using the CCC and AAA algorithms.For CCC and AAA,
varying the MLC margin between 3 and 10 mm for all patients, the margin
found to maximise dose escalation and provide the best tumour coverage
according to rNTDmean lies between 5 and 7 mm (Fig 1). This same range
of optimal margins is found when breathing motion is taken into account using
4D dose accumulation calculation in 6 or 10 phases.
Conclusions: For isotoxic schedules the PTV dose coverage should be carefully chosen in order to maximise target doses deliverable for a constant predicted level of lung toxicity. For the IDEAL-CRT trial, if the AAA and CCC
algorithms are used, a V90 of 98-99% of the PTV is achievable using an MLC
margin of 5-7 mm, and is equivalent to a V95 of 98-99% for the PBC.This conclusion is valid if the tumour moves up to 2 cm in amplitude due to respiratory
motion. AcknowledgementWe thank PHILIPS Oncology Systems for making
available the Pinnacle Research interface. [1] V.Panettieri, Z Malik, C Eswar,
D Landau, J Thornton, A Nahum, P Mayles, J Fenwick" Influence of dose calculation algorithms on isotoxic dose-escalation of non-small cell lung cancer
radiotherapy", 2010, Radiotherapy and Oncology, 2010 Dec;97(3):418-24.

Purpose: In Breast radiotherapy, it is well established the practice to extend
dose fluence outside the average CT body contour, both in 3D conventional
and in static IMRT planning technique. From the practical point of view, thesame approach (e.g. opening beam size, fluence extension, etc), is not transferable to VMAT planning. In this study, a planning strategy in the Varian
environment to overcome these limitations is proposed and evaluated.
Materials: RapidArc (RA) plans for 6 breast cancer patients (3 right and 3
left cases), were optimised (PRO version III) on the original CT data set (O)and on an expanded one (E), where body in the breast region and PTV contours were extended in air (and tissue HU assigned). Final dose calculation
for the 2 plans was performed on the same original CT data set O, normalizing the dose prescription (50Gy) to target mean. In this way, two treatment
plans on the same CT set O for each patient were derived: the no action plan
(OO) and the alternative plan based on an expanded optimization (EO).Fixing
MU, these 2 plans were also recomputed on the 1 cm expanded CT data
set and on an intermediate one (expansion=0.5cm), to mimic, in particular,
breast shape change due to oedema during treatment. This allows to quantify the robustness of dose distributions from RA plans when the OO or the
EO strategies are adopted. For all the combinations, a DVH analysis of all
involved structures is reported.
Results: I. The two optimisation approaches give comparable dose distributions on the original CT data set. II. When plans are evaluated on the
expanded CTs (i.e. when patient present oedema), the EO approach show
to be significantly superior to OO in guarantee target coverage: on CT_1cm,
DV=98%[%]=92.5+0.9, 68.5+3.1 respectively for EO and OO. Minor changes
are registered in terms of organ sparing for both EO and OO respect to theoriginal studied plans. III. From dose distributions and DVHs, it is evident
that EO approach allows to irradiate the expanded target region as usuallyachieved in the past with skin flashing of treatment fields; this would account also for intrafraction movements. If oedema has to be considered, are-calculation of the plan on a new CT data set to have the correct amount of
MU could be addressed to guarantee the correct target coverage. Probably,
this step could be limited to a small subset of patients, for whom big changes
would early appear.
Conclusions: The proposed plan strategy can represent a good solution tobenefit of dosimetric improvements and logistical advantage of RA planningrespect to the static IMRT, without compromising its robustness due to thepresent lack of any semi-automatic skin flashing management.

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402 poster
GEUD-BASED OPTIMIZATION FOR HDR PROSTATE BRACHYTHERAPY: NUMERICAL STABILITY AND SENSITIVITY ANALYSIS
D. Giantsoudi1 , A. Karabis2 , P. Mavroidis3 , D. Baltas4 , C. Shi1 , N.
Papanikolaou1
1
CTRC @ UT HSC AT S AN A NTONIO, Radiation Oncology, San Antonio,
USA
2
PI M EDICAL, Athens, Greece
3
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Stockholm,
Sweden4
K LINIKUM O FFENBACH G MB H, Offenbach am Main, Germany
Purpose: An inverse planning optimization tool based on the generalized
equivalent uniform dose (gEUD) has been suggested for HDR prostatebrachytherapy by our previous work (Giantsoudi et al ESTRO 2010), whichindicated the potential of improved sparring of the organs at risk (OAR). In
the present study, the numerical stability and sensitivity of this new inverse
planning technique is investigated.
Materials: For a given patient geometry, catheter position pattern and initial set of source dwell times (t0), the BFGS quasi-Newton method is implemented to calculate the set of source dwell times that minimize the gEUD
objective. To verify the numerical stability of this model, 150 optimized solutions were obtained for a clinical case of HDR prostate brachytherapy implant,
varying only t0, in the range of -500 to 500 sec. Statistical analysis of the 150
optimized sets of dwell times and resulting values of dosimetric evaluators
was performed using the root mean square deviation (RMSD) as well as themean and standard deviation (SD) quantities. The sensitivity of the optimization system was studied by varying the importance factors (n-parameters) of
the objectives in the range of 0-20 for the structures of the prostate-PTV (target), prostate-OAR (used to set an upper dose limit to the target) and normal
tissue (ring surrounding the prostate), for various clinical cases. The conformal index (COIN-Baltas et al 1998) was calculated for each case and plottedagainst the values of the importance factors (Figure).
Results: The convergence analysis showed less than 0.0001% discrepancies in the resulting dosimetric evaluators for the 150 differently initialized
optimized solutions, and a mean RMSD value of less than 10-3 sec for the optimized sets of dwell times, indicating the successful convergence of the optimization algorithm. The sensitivity analysis showed a stronger dependence
on the prostate-PTV importance factor over the range of the studied values
compared to the other studied structures. The set of the importance factor
values that maximize COIN in all the cases [n(prostate-PTV) = 18, n(prostateOAR = 2), n(NT) = 2] is proposed as the default optimization protocol for thismethod.

401 poster
A TRANSFORMATION APPROACH FOR DOSE CALCULATION IN A
MAGNETIC FIELD
A. Pfaffenberger1 , U. Oelfke1
1

G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Medical Physics inRadiation Oncology, Heidelberg, Germany
Purpose: Efforts exist to integrate magnetic resonance imaging (MRI) withconventional linear accelerators (linacs) or cobalt devices. Online image guidance using MRI is desired due to its excellent soft-tissue contrast, its potential
for physiological imaging and the lack of ionizing radiation such that imaging
time and frequency are not an issue. Other groups have described the effectof a magnetic field (MF) on the physical dose distribution (DD) with the helpof Monte Carlo (MC) simulations. Presently, MC is the only existing calculation method for DDs in a MF. In this work, an approach is presented thattransforms a DD without any MF into one that would be generated if a MF
was applied.
Materials: Two assumptions are made. First, that also in a MF, the DD
in homogeneous media can be described by a convolution of the photon

Conclusions: The T shows good results in homogeneous media, while heterogeneities are not yet modelled. It presents a first approach in the direction of kernel-based dose calculation in a MF and it is still to be determined
whether it has the potential to be extended to an accurate method also incorporating heterogeneities. Using only a single convolution, it may then be fastenough to assist online re-planning.

Conclusions: Our study verifies the convergence ability of the algorithm toa solution over a wide range of initializing dwell times. The sensitivity of themethod over a range of importance factors was studied and a default set ofparameters maximizing COIN is suggested.
403 poster
COMPARISON OF TWO PERMANENT PROSTATE SEED IMPLANT
BRACHYTHERAPY TECHNIQUES - INCLUDING POST-IMPLANT
EVALUATION
K. Andersen1 , P. F. Geertsen1 , B. Holch Kristensen1
1
H ERLEV H OSPITAL, Radiation Therapy, Herlev, Denmark
Purpose: To evaluate and document the use of real-time intraoperative (IO)
planned prostate brachytherapy, the IO technique is compared to a standard

S 160P OSTER

preplanning (PP) technique on both ultrasound based implant plan (IP) andon 3D CT based post-plans (CTPP).
Materials: 40 patients are included in this study. 20 patients are implantedusing PP and 20 using IO. Both techniques use the same dose constraints
with an ordinated dose of 144Gy.The PP plans were performed in the Nucletron Plato system and the implantation technique is based on stranded seeds
and a modified uniform loading.The IO plans were performed in the VariSeed
system end the implantatione technique is based on loose seeds and on peripheral loading.CTPP for all 40 patients (both techniques) was done in the
VariSeed system with a CT scan aquired approximately one month after implantation.The main differences in treatment parameters (e.g. total activity,
number of seeds and needles) and setup for both personnel and patient aredescribed.The dose to the patient is on both IP and CTPP evaluated on fourparameters: 1) dose to 90% of the prostate (D90), 2) percentage of prostaterecieving 100% of ordinated dose (V100), 3) percentage of prostate recieving
150% of ordinated dose (V150) and 4) rectum volume recieving more than
144Gy (Vrectum144). The most important parameter is D90 since it correlates to PSA free survival. V150 and Vrectum144 relates to unwanted side
effects.
Results: There is no significant difference in the mean total activity and mean
number of seeds, while the mean number of needles is significantly less using IO.There is no significant difference in mean D90 dose coverage for IP[D90(PP)=169.2±3.8, D90(IO)=174.3±6.0 (p>0.05)], while for CTPP a significant difference is observed [D90(PP)=149.5±14.2, D90(IO)=165.7±22.1(p<0.001)]. Five PP CTPP did not fulfill the dose constraint D90>144Gy.
This was only the case for one IO CTPP.The other parameter evaluatingdose coverage V100 shows similar results with no significant difference in
IP while significantly better coverage is observed with CTPP.V150 evaluates
the overdosage volume size and for both IP and CTPP a significantly higher
mean volume size is seen in the IO plans [V150,CTPP(PP)=49.7±13.6%,
V150,CTPP(IO)=64.3±9.8% (P<0.001)]High dose volume to the rectum
Vrectum144 is also significantly higher in the IO plans evaluated with both
IP and CTPP.
Conclusions: The IO technique resulted in the best tumor coverage evaluated on CTPP. 95% of the IO plans had D90>144Gy, while this was only
was only the case for 80% of the PP cases.The IO technique however has
more overdosage evaluated on CTPP in both prostate and rectum.Despite of
the overdosage issue the IO technique is recommended for treatment due tobetter tumor coverage, more flexible planning and treatment scheduling andsince no adverse events related to rectum is observed on the 20 IO patients.
404 poster
SENSITIVITY OF CALCULATED TUMOR CONTROL ON CHOICE OF
BIOLOGICAL PARAMETERS FOR LDR PROSTATE IMPLANTS
N. Papanikolaou1 , C. Knaup2 , P. Mavroidis3
1

C ANCER T HERAPY, San Antonio, TX, USA
CTRC @ UT HSC AT S AN A NTONIO, San Antonio, USA
3
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Stockholm,
Sweden2

Purpose: Biological parameters used in the calculation of tumor control probability (TCP) have been reported with considerable variation. It then becomes
important to explore the effects that different parameters have on the calculation of TCP. In this work, the effect of using different combinations of biological parameters for tumors in low dose-rate brachytherapy (LDR) prostate
implants was explored.
Materials: Forty-four LDR prostate patients were used in this study. All thepatients were treated with Palladium-103 seeds and were planned on the
Spot treatment planning system. The prescription doses for the patients were
either 90 Gy or 120 Gy. The 90 Gy patients were to receive additional radiotherapy, but were used in this study to determine the effects of different
biological parameters at a lower physical dose level. A post-implant CT was
taken for each patient and was used for post-implant planning. From eachpost-implant plan, a dose-volume histogram for the tumor was created. Using
this dose information and different biological parameters, the linear-quadraticmodel was used to calculate the biological effective dose (BED) to the tumor
for each patient. The BED was then used to calculate the TCP for each patient. Combinations of the following biological parameters were evaluated:
α/β = 2, 3, 4 Gy; maximum normalized dose-response gradient (γ ) = 2, 3, 4;
and D50 = 30, 50, 70 Gy. The TCP for each patient was calculated for eachof the twenty-seven different combinations.
Results: The combinations that had the highest TCP value at a given low
BED level were those were D50 was low and α/β and γ were high. For manyof these combinations the patients’ calculated TCP was unrealistically high.
The combinations for which the TCP value was low at given high BED levels
were those were D50 was high and α/β and γ were low. Parameter values of
α/β = 2 Gy, D50 = 50 Gy and γ = 4 were determined to provide TCP values
that are most consistent with realistic patient outcomes. These parameters
also yield an α value that was consistent with newer findings.
Conclusions: In this study, the sensitivity of TCP calculations on biologicalparameter choices was evaluated for LDR prostate brachytherapy patients.
This was done by calculating the BED to the tumor and subsequently the corresponding TCP. The parameters that best matched realistic clinical results
were α/β = 2 Gy, D50 = 50 Gy and γ = 4.

W EDNESDAY, M AY 11, 2011
Young scientists ESTRO Poster Session: High
precision techniques: stereotactic and protons
405 poster
CONTRIBUTION OF FLATTENING FILTER FREE BEAMS TO
EXTRACRANIAL STEREOTACTIC VMAT TREATMENT OF NSCLCPATIENTS
J. Hrbacek1 2 , S. Lang1 , S. Graydon1 , S. Klöck1 , O. Riesterer1
1
U NIVERSITY H OSPITAL Z ÜRICH, Department of Radiation Oncology,
Zurich, Switzerland
2
PAUL S CHERRER I NSTITUTE, Villigen - PSI, Switzerland
Purpose: This study aims to evaluate contribution of flattening filter free(FFF) beams of TrueBeam linear accelerator (Varian Medical Systems, Palo
Alto, USA) to stereotactic body radiotherapy (SBRT) of early stage non-small
cell lung carcinoma (NSCLC) patients.
Materials: In total 11 patients with stage I peripheral non small cell lung cancers were subject to 4DCT based SBRT treatment planning. PTVs ranged
between 14 and 150 cm3 . VMAT plans (Eclipse, Varian Medical Systems)
were prepared, using 2 full arc fields with 90 degree angular separation of collimator and utilizing avoidance sectors where a contra-lateral lung fully covers
PTV. Plans were optimized to deliver 50 Gy in 5 fractions and to produce dose
distributions that meet criteria defined by the RTOG 0915 protocol. Each plan
was optimized for three different energies (X6FFF, X6, and X10FFF) using
the same constraint set and allowing maximum dose rate for each energy,
i.e. 1400, 600, and 2400 MU/min. Obtained dose distributions were analyzed
and additional quantitative parameters (MU, dose inhomogeneity in a target,
dose to healthy tissue, conformity index, max dose at 2 cm away from PTV(D2cm), volume enclosed by 50% of prescription dose (V25Gy/VPTV), organat-risk sparing) were compared using paired Wilcoxon test. Plan verification
was performed using Delta4 system (Scandidos, Sweden).
Results: Dose distributions achieved for the three beams are comparable.
With increasing PTV size, FFF plans require higher number of MUs than X6plans (up to +25 % for 150 cm3 PTV), yet mean body dose does not change
due to missing dose in lateral direction for FFF beams. Good conformity
was obtained in all cases (CI<1.10). Dose gradient specifying parameters
demonstrate best results for X6FFF beam, which systematically creates the
sharpest gradient. In comparison to X6 plans, mean distance between 50 Gy
and 25 Gy isodose is on average reduced by 4.2 %, V25Gy/VPTV by 4.6 %(both p<0.001). V20Gy and V12.5Gy for lung are reduced by 5 %, if X6 beamis replaced with X6FFF (p<0.001). No statistically significant differences were
found between X10FFF and X6 beams. Utilizing FFF beams significantly
reduces treatment time. Whereas mean beam-on time was 111 s (2 SD = 11s) for X10FFF and 128 s (2 SD = 19 s) for X6FFF, X6 plans require on average
269 s (2 SD = 71 s). Good agreement was observed for the verification of allplans.
Conclusions: VMAT treatment utilizing FFF beams yields dose distribution
comparable to the one obtained for flattened beams deliverable at significantly
reduced beam-on times. X6FFF beam produces the sharpest gradient, whichleads to the best sparing of surrounding lung tissue.
406 poster
DOSIMETRIC CHARACTERIZATION OF A NOVEL STEREOTACTIC
RADIOTHERAPY DEVICE FOR BREAST CANCER
Y. Mutaf1 , C. Yu1 , J. Zhang2 , K. Prado1 , S. Feigenberg1 , B. Yi1 , W.
D’Souza1 , W. Regine1
1
U NIVERSITY OF M ARYLAND S CHOOL OF M EDICINE, Department ofRadiation Oncology, Baltimore, MD, USA
2
X CISION M EDICAL S YSTEMS, Maryland, USA
Purpose: A dedicated stereotactic gamma irradiation device, GammaPodTM
from Xcision Medical Systems, has been developed to treat early stage breast
cancer. This study presents the first set of dosimetric and geometric characteristics of a prototype unit installed at University of Maryland Radiation
Oncology Department.
Materials: The GammaPodTM device consists of a hemi-spherical source
carrier containing 36 60 Co sources, a series of tungsten collimators with 2
built-in collimation sizes, a dynamically controlled patient support table, and abreast immobilization cup that also functions as the stereotactic frame for thepatient. The source carrier contains 36 sources spaced 1 degree apart laterally and 10 degrees apart longitudinally. The carrier rotates together with thevariable-size collimator to form 36 non-coplanar, concentric arcs focused at
the isocenter. Total activity of 4400 Curies provides a dose rate of about 4.0
Gy/min at the isocenter. The treatment table enables motion in three dimensions to position the target at the focal point in the prone position. The table
can also move continuously during treatment to dynamically shape the dose
distribution. The breast is immobilized using a two-layered breast cup witha negative pressure applied between the layers. Embedded imaging fiducials in the outer cup function as the stereotactic frame. Spatial accuracy andthe localization uncertainty were evaluated for both the immobilization andpositioning systems. Dosimetric characteristics of the unit are modeled with
Monte Carlo simulation using the actual source size and collimation struc-W EDNESDAY, M AY 11, 2011
ture, and the calculated dose distributions are compared to ion chamber andradiochromic film measurements.
Results: With 36 non-coplanar arcs and a dynamic dose shaping feature, theGammaPodTM can deliver uniform doses to targets of up to 8.0 cm with good
conformity. Spatial accuracy of the unit itself is less than 0.05 cm. Localization
accuracy for breast lesions are also evaluated and reported to be less than
0.2 cm. Figure 1 shows the dosimetric profiles achieved with two sizes ofcollimators; 1.5 and 2.5 cm. The single shot penumbra (80% to 20% isodoseline) for 1.5 and 2.5 cm collimators were 0.8 and 1.1 cm respectively in xz coronal plane and 0.6 and 0.9 cm in the y-z sagittal plane. Verifications ofdose profiles using single shot distributions demonstrated agreement with thespatial accuracy specifications of the unit.

P OSTERS 161

based on the statistical correlation function between the three-dimensionaldose distribution and the PTV while the OAR fitness function is based on
the volume-weighted normalized dose computed from the dose-volume histogram (DVH).
Results: PARETO treatment plans (DVHs and dose distributions) using
coplanar beams will be presented for a spine tumour case containing several
OARs. A trend of improved dose conformity to the PTV with an increasing
number of optimized beams is apparent until a threshold is reached beyond
which changes in the PTV dose conformity are small (Figure 1). The degreeof OAR sparing will be compared between plans with a varying number of
optimized beams.

Conclusions: Thus, from many Pareto-optimal plans, the clinician may select the plan which they decide is the most appropriate multi-objective compromise for a particular patient.
408 poster

Conclusions: The dosimetric potential of the GammaPodTM stereotactic
breast radiotherapy device is characterized. The agreement between the
MC based calculations and dosimetric measurements is reported for a single shot irradiation, as well as for treatments implementing dynamic dose
shaping techniques.
407 poster
MULTI-OBJECTIVE SBRT TREATMENT PLANNING USING PARETO
P. Potrebko1 , J. Fiege2 , B. McCurdy3 , H. Champion2 , A. Cull2
1
W INNIPEG H EALTH S CIENCES C ENTRE, Research, Winnipeg, Canada
2
U NIVERSITY OF M ANITOBA, Physics and Astronomy, Winnipeg, Manitoba,
Canada3
C ANCER C ARE M ANITOBA, Medical Physics, Winnipeg, Manitoba, Canada
Purpose: Stereotactic body radiation therapy (SBRT) treatment planning isfundamentally a multiobjective global optimization problem because clinicalobjectives are invariably in conflict and compromises are necessary. We propose a novel and powerful beam number and orientation optimization package for radiotherapy optimization, called PARETO (Pareto-Aware Radiotherapy Evolutionary Treatment Optimization), which consists of a multi-objective
genetic algorithm capable of optimizing several objective functions simultaneously and mapping the structure of their trade-off surface efficiently andin detail. Given one or more objective functions for each region-of-interest(ROI), a Pareto-optimal treatment plan is one for which there does not exist
another plan that is strictly better in at least one objective function while being no worse in every other ROI objective. PARETO generates a databaseof Pareto-optimal solutions and allows the graphical exploration of trade-offs
between multiple planning objectives during IMRT treatment planning.
Materials: Multiobjective beam number and orientation optimization isachieved through a genetic algorithm called Ferret, part of the Qubist global
optimization package which is a third party global optimization toolbox for
MATLAB, available from nQube Technical Computing Corporation. The current version of PARETO utilizes ray-tracing methods to calculate the primary dose, including divergence, attenuation, and inverse-square law effects,
which is then convolved with a scattering kernel to simulate patient scatter. Rays are assumed to be conformal to the projection of the PTV in thebeam’s-eye-view plane, and are modulated by a parameterized fluence pattern at each beam angle. In this work, the fluence pattern is modeled by aninverse cosine transform whose coefficients are treated as free parameters
and optimized using multiobjective fitness functions, that robustly encode theattributes of the dose distribution, by PARETO. The PTV fitness function is

CLINICAL AND RADIOLOGICAL OUTCOMES OF STEREOTACTIC
RADIOTHERAPY WITH TOMOTHERAPY FOR PATIENTS WITH
OLIGOMETASTATIC BRAIN LESIONS
M. Galeandro1 , P. Ciammella1 , E. Donini1 , N. D Abbiero1 , A. Muraglia1 , E.
Cagni2 , A. Botti2 , C. Iotti1
1
A RCISPEDALE S. M ARIA N UOVA, Radiation Oncology, Reggio Emilia, Italy
2
A RCISPEDALE S. M ARIA N UOVA, Medical Physics, Reggio Emilia, Italy
Purpose: A significant proportion of adults with cancer will develop brain
metastases. The outcome for these patients is generally poor, with a mediansurvival following whole brain radiotherapy alone of only 3-4 months regardless of primary tumor histology. These results have shed light on the possibility of improving outcomes, in terms of local control, overall survival andquality of life, by using high-dose local radiotherapy in the treatment of brain
oligometastases. The aim of the present study was to retrospectively evaluate
the dosimetric parameters and the radiological response rate of stereotactic
radiation therapy (SRT) for patients affected by brain oligometastases.
Materials: Twenthy one patients with 1-3 brain metastases, treated between
January 2009 and December 2010 with stereotactic radiation therapy, using
Tomotherapy Hi-ART, were analyzed. The most common histology of themetastatic lesion was non small cell lung cancer (9), followed by breast cancer(6), renal cancer (2), rectal cancer (2) and melanoma (2). To be eligible
for SRT, patients had to have a Karnofsky performance status greater than
70% and have stable systemic disease. Any patients had received prior brain
radiotherapy.At the time of brain metastases diagnosis, 6 patients had an inoperable single brain lesion and 15 patients had 2-3 lesions, measuring lessthan 3 cm in maximum diameter and producing minimal mass effect. All patients, immobilized by a thermoshell in supine position, underwent computed
tomography (CT) scan for radiotherapy planning. Magnetic resonance imaging (MRI) scan with Gadolinium contrast was performed in all patients andfused with CT images to draw the macroscopic (gross) tumour volume (GTV)
and the organs at risk (OAR) (eyes, lens, optical nerves, chiasma, brainstem).
A 3 mm margin was added to the GTV to create the planning target volume(PTV). A total dose of 24 Gy, prescribed to the 70% isodose line, was administered in three consecutive fractions. Plans were optimized for conformity andtarget coverage with maximum OAR sparing. A Tomotherapy megavoltage
computed tomography (MVCT) was performed every day to verify and correct the patient set-up.Patients were seen 6-8 weeks after SRT completionand the local tumour response was evaluate with MRI, using the McDonald
Criteria. Any toxicity was recorded according to the National Cancer InstituteCommon Terminology Criteria for Adverse Events (CTCAE vs 3.0).
Results: Twenthy one patients (median age 67 years, range 50-87 yrs) witha total of 41 lesions (with mean diameter 1.68 cm, range 0.7-2.8 cm) wereanalyzed. The mean GTV volume was 4.73 cc and the mean PTV was 13.10
cm3 Dosimetric results were as follows: the mean conformity number was
0.85 + 0.1 with a median target coverage of 0.98 + 0.01. Intralesional dose

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P OSTERS 163

averaged a maximum of 34.3 Gy and a minimum of 24 Gy. The mean time
to delivery a single treatment was 6.9 min. The shortest time (4 min) was
measured for a plan with single metastasis, while the longest time (10.2 min)for a plan with three metastases. The mean time to perform and evaluate the
MVCT was 5 min (range 4-8 min).From a clinical point of view, radiologicalresponse was rapid in the patients with adenocarcinoma metastases, whileslight reduction or stabilization occurred in those patients with melanoma andrenal carcinoma. At a mean follow up of 14.4 months (range 1-23), the overall
median survival was 14.4 months, with one-year survival rate of 45%. At last
follow up local control was 81%, with radiological evidence of radionecrosis
in 2 pts. Only eight lesions failed in the treated volume or in its immediate
margins. No major acute toxicity occurred. Although four patient had transient general seizures on the treatment day of RT, they were soon managedwith an administration of a corticosteroid. As to chronic toxicity, one patientunderwent surgical resection for localized radiation necrosis after 3 months
from RT. Except for the 1 patient, no other major chronic CNS toxicity wasrecorded in the 21 patients evaluated.
Conclusions: Precise stereotactic radiotherapy was effective and safe intreatment of oligometastatic brain lesions, and allow the treatment salgave
with local radiotherapy or whole brain RT of brain recurrence. Taking into
consideration significant prognostic factors should help us to choose an appropriate way of treatment for each patient, and further investigation with respect to the "oligometastases situation" might offer novel findings of importance that could be incorporated in designing a new-stage treatment strategy
with stereotactic radiation treatment.
409 poster
ENERGY SPECTRUM UNCERTAINTIES IN RADIATION THERAPYWITH LASER ACCELERATED PARTICLES
S. Schell1 , J. Wilkens1
1
K LINIKUM RECHTS DER I SAR , TU M ÜNCHEN, Department of Radiation
Oncology, München, Germany
Purpose: Laser plasma acceleration of charged particles for radiation therapy may become a compact and cost efficient alternative to synchrotrons andcyclotrons. However, many problems are yet to be solved. Here we address
the reproducibility of the energy spectrum of the accelerated particles andevaluate the effect of spectral uncertainties on the resulting dose distributions.
Materials: We assume the existence of an energy selection system[1] thatdefines a lower and an upper bound of the transmitted particle energies on ashot to shot basis. The energy width of the used spectra can be determinedby an algorithm that maximises beam efficiency while preserving plan quality[2]. However, due to the uncertainties in the laser acceleration process, theparticle fluence per energy within the window of transmitted energies is subject to fluctuations. We analyse the influence of systematic and statistical uncertainties on both spread-out Bragg peaks (SOBPs) and three dimensional
patient plans.
Results: The analysis of SOBPs shows that for reasonable spectral uncertainties the dose stays homogeneous within the whole tumour. This is mainly
due to the fact that the minimal and maximal transmitted energies are notaffected by the simulated uncertainty. Even for broad spectra (e.g. 20 MeV)
a redistribution of particles to different energy bins within the transmission
window is of minor importance. Figure 1 shows the irradiation of a SOBP
where the spectrum used for planning (denoted by "0") is subject to Gaussian shaped statistical changes (1-sigma alteration in each direction ("+"/"-")).
Each of the 5 different SOBPs illustrates one possible resulting dose. The total number of transmitted particles is a good measure for the effects of theuncertainty. If the total amount of particles is higher or lower than intended,
the dose level will change correspondingly. Therefore, systematic uncertainties may be characterised by the total number of used particles. The impact
of statistical uncertainties is influenced by the number of shots used to irradiate each tumour spot. A high number of shots per spot levels out all statisticaluncertainty.

Conclusions: Even for broader energy spectra, the total number of transmitted particles is a good measure for the energy spectrum uncertainty of laser
accelerated particles. The error in dose is roughly proportional to the error
in the total number of particles. A high number of shots levels out statisticaluncertainties.Acknowledgement: Supported by DFG Cluster of Excellence:
Munich-Centre for Advanced Photonics.
References:
1. Fourkal, Li, Ding, Tajima and Ma; Med Phys 30:1660-70; 2003

Conclusions: Despite the 5 mm CTV-PTV margin used in this study, for threeout of five patients a systematic shift of 1 to 2 mm resulted in a violation ofdose criteria in a common three-field geometry. This underlines the needto evaluate plans on the impact of systematic alignment errors with respect
to the dose to the target and critical volumes. Simple modifications in usedbeam geometries may be needed to maintain the benefits associated with a
ssIMPT plan.

2. Schell and Wilkens; Med Phys 37:5330-40; 2010

410 poster
IMPACT OF SYSTEMATIC ALIGNMENT ERRORS ON SPOTSCANNED INTENSITY-MODULATED PROTON THERAPY FOR HEAD
AND NECK CANCER
H. van Herpt1 , T. van de Water1 , H. P. van der Laan1 , C. Schilstra1 , P. vander Hulst1 , H. Langendijk1 , A. van ’t Veld1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Oncology, Groningen, Netherlands
Purpose: To verify the impact of systematic translational alignment errors on
spot-scanned intensity-modulated proton therapy (ssIMPT) plans in the headand neck region with respect to the dose to the target volumes and normal
tissues.
Materials: ssIMPT plans in a common three-field geometry (gantry angles
180, -50 and 50) were created for five patients with oropharyngeal cancer
who were indicated for primary radiotherapy for the bilateral neck. A CTV to
PTV margin of 5 mm was applied conform our clinical protocols. Elective andboost PTV prescriptions, with prescription dose 54 Gy (PTV54) and 70 Gy(PTV70), respectively, were combined using a simultaneous integrated boost
technique. Each plan was optimized (XiO, Elekta) with criteria for adequate
PTV coverage (≥98% of volume ≥95% of dose; ≤2% of volume >107%dose), sparing the parotid glands as much as possible and limiting the spinal
cord dose (≤ 2% of volume ≥ 50Gy). The impact of systematic alignment
errors was quantified by simulating isocentre shifts of -2, -1, 1 and 2 mm inlateral (X), longitudinal (Y) and vertical (Z) directions, i.e. 12 shifted plans
per patient, and checking our criteria for CTV and normal tissues. In one of
the cases where the criteria were exceeded using shifts, an alternative beamgeometry was applied to remedy this, by splitting the most critical beam, e.g.,
in a geometry with -150, -50, 50 and 150 gantry angles.
Results: In general, a shift in the vertical direction had the least impact on
the evaluated criteria. No translational alignment error violated the spinal
cord criterion.For the CTV70 one violation of the V95 CTV criterion resulted
from a 1mm lateral shift in one patient (V95 was 97.1%), and three violations
resulted from 2 mm shifts in three patients (5 shifted plans, V95 range was95.3-97.4%). In all unshifted plans, one parotid gland was deliberately sparedand received a mean dose of <23 Gy. For this gland, the applied shifts yielded
increases in mean dose from -3.4 Gy to +6.3 Gy (Figure 1). A correction
with additional CTV to PTV margin to meet the CTV V95 criterion in thesecases would have further increased the mean dose to the parotid gland. In
contrast, the violation of the CTV V95 could be easily overcome with a splitbeam adaptation in a four-field plan.

Conclusions: rsIMPT improved sparing of the salivary glands, while maintaining similar target coverage. This was expressed in a statistically significant
reduction of the NTCP for (1) xerostomia and (2) parotid and submandibular
salivary dysfunction.

Young scientists ESTRO Poster Session: IMRT optimisation

411 poster

412 poster

INTENSITY-MODULATED PROTON THERAPY WITH A REDUCEDSPOT SIZE IMPROVES SALIVARY GLAND-SPARING IN OROPHARYNX CANCER
T. van de Water1 , A. Lomax2 , H. P. Bijl1 , C. Schilstra1 , E. Hug2 , H.
Langendijk1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Oncology, Groningen, Netherlands
2
PAUL S CHERRER I NSTITUTE, Center for Proton Radiation Therapy, Villigen- PSI, Switzerland

PROBABILISTIC TREATMENT PLANNING FOR DOSE-ESCALATIONIN NSCLC: FIRST RESULTS
G. Shakirin12 , W. van Elmpt2 , M. Witte3 , M. Bal4 , M. van Herk3 , P. Lambin2
1
P HILIPS R ESEARCH, Eindhoven, Netherlands
2
MAASTRO CLINIC, Maastricht, Netherlands
3
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands
4
P HILIPS H EALTHCARE, PO Box 80068, Netherlands

Purpose: The second-generation proton gantry that is under development
at the Paul Scherrer Institute allows upstream energy regulation, yielding a
reduced spot size as compared to the currently used gantry. In this planningcomparison study, we investigated whether intensity-modulated proton therapy (IMPT) with a reduced spot size (rsIMPT) could reduce the parotid andsubmandibular gland dose compared with previously calculated IMPT plans
with a larger spot size. In addition, we investigated if the obtained dose reductions would theoretically translate into a reduction of the probability of salivary
dysfunction and xerostomia.
Materials: Ten patients with N0 oropharyngeal cancer were included in an
in silico planning comparative study. All IMPT plans delivered simultaneously
70 Gy to the boost planning target volume (PTV) and 54 Gy to the elective
nodal PTV. IMPT and rsIMPT used identical 3-field beam arrangements. In
the simulated rsIMPT plans the Gaussian cross section of the pencil beam
had an initial σ of 3.5 mm in air (identical to the initial σ in IMPT plans),
which, in contrast to the simulated IMPT plans, was not degraded by range
shifter plates (used for energy modulation). In the IMPT plans the parotid andsubmandibular salivary glands were spared as much as possible. rsIMPTplans used identical dose-volume objectives for the parotid glands as thoseused for the IMPT plans, whereas the objectives in the rsIMPT plans for thesubmandibular glands were further tightened. Existing normal tissue complication probability (NTCP) models were used to calculate NTCPs for salivary
dysfunction and xerostomia.
Results: Target coverage was similar for both IMPT techniques, whereas
rsIMPT clearly improved target conformity (the conformity index reduced from1.40 with IMPT to 1.23 with rsIMPT). The mean doses in the parotid glands
and submandibular glands were significantly lower for three-field rsIMPT(14.7 Gy and 46.9 Gy, respectively) than for 3-field IMPT (16.8 Gy and 54.6
Gy, respectively), p< 0.01. Hence, rsIMPT significantly reduced the NTCP
of patient-rated xerostomia and parotid and contralateral submandibular salivary flow dysfunction (27%, 17% and 43% respectively) compared with IMPT
(39%, 20% and 79%, respectively). In addition, mean dose values in the sublingual glands, the soft palate, and oral cavity were also reduced (Table 1). Of
note is that in a previous study we showed that, compared with photon IMRT,IMPT with the standard spot size did not significantly reduce the dose to thesubmandibular glands. In contrast, the current study shows that rsIMPT doessignificantly reduce the contralateral submandibular gland dose (Table 1).

Purpose: Dose escalation to the target based on organs at risk (OAR) constraints as well as various dose painting strategies based on information
about radiosensitivity of tumor subregions are of high interest nowadays. Different approaches exist to account for uncertainties of tumor location in thetreatment planning: (i) extend clinical tumor volume (CTV) to the planned tumor volume (PTV) using margins based on expected systematic and random
errors, (ii) in probabilistic approach the IMRT objectives are based on the distribution of possible CTV locations instead of a PTV. The aim of this work is tocompare probabilistic and margin based treatment planning approaches fortwo dose escalation strategies in NSCLC.
Materials: Treatment plans were designed for patients eligible for dose escalation using a margins approach and a custom probabilistic IMRT objective approach in the Pinnacle TPS, research version 9.100 (Philips Radiation
Oncology Systems, Fitchburg, WI, USA). Probabilistic plans accounting forpatient systematic (Σ=0.29 cm) and random (σ =0.1 cm) set-up errors weregenerated using a confidence level of 90%. Systematic set-up errors were
simulated by shifting target volumes with respect to the dose. The random
errors were simulated by dose blurring. Margin based treatment plans weredone using the standard 8 mm CTV to PTV margin; i.e. corresponding toabove mentioned systematic and random errors. Margin based and probabilistic plans were created for two dose escalation strategies: a) non-specificuniform dose escalation to the target and b) dose boosting of the area of
50 % and more of SUV maximum derived from the FDG PET scan. All plans
were normalized to the same mean lung dose. The final dose distribution wastested using a standalone Monte Carlo evaluation tool which creates 10000
histories of possible target positions according to given systematic and random errors and calculates mean DVHs. Two scenarios were tested: normal(Σ=0.29 cm, σ =0.1 cm) and worst case (Σ=0.35 cm, σ =0.3 cm).
Results: The mean dose inside the CTV was 8 Gy higher for the probabilistic plans compared to the standard plans for both dose escalation strategies.
The mean dose inside the high SUV uptake region was 14 Gy higher in theprobabilistic planning. The inhomogeneity of the dose inside CTV increased
for the probabilistic plans whereas the dose to the OARs (esophagus, spinalcord) was even slightly decreased. DVHs of probabilistic planning are influenced more in worst case scenario, showing, however, robustness to increasing errors.

S 164

P OSTERW EDNESDAY, M AY 11, 2011
413 poster
REDUCING TRIAL-AND-ERROR WITH PROBABILISTIC
PLANNING FOR PROSTATE CANCER
R. Bohoslavsky1 , M. Witte1 , T. Janssen1 , M. van Herk1

IMRT

1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands

Purpose: Probabilistic planning allows treatment optimization and evaluation
without using explicit safety margins. This added flexibility generally leads tobetter compromises when PTV and OARs overlap. We are currently developing a practical planning system for future clinical use. Because probabilisticplanning has more freedom to optimize, we expect that less user intervention
will be needed to obtain a good plan. Our aim was therefore to study the potential reduction in trial-and-error steps during plan optimization for prostatecancer.
Materials: Probabilistic optimization was implemented by extending the clinical cost functions of the Pinnacle TPS research version to include the effect of translational and rotational geometrical uncertainties. Random errors
are incorporated by blurring the dose distribution. Systematic errors are included by rotating and shifting the CTV with respect to the blurred dose. The
same geometrical uncertainties are applied in our in-house developed evaluation tool to analyze the resulting plans.In clinical practice, treatment plans
are first optimized using a standard set of objectives (default plan) which aresubsequently manually modified until a clinically acceptable plan is achieved(clinical plan). The actual number of additional optimizations depends on theplanner’s expertise and the characteristics of the patient. In this study clinicalplans were re-planned applying a set of probabilistic objectives (probabilisticplan). Comparing these three plans allows estimation of the potential reduction in trial-and-error steps needed to obtain an acceptable plan.
Results: SIB treatment plans from 41 prostate cancer patients were evaluated. The typical optimization time for probabilistic and standard plans
was 10 and 2 minutes respectively. The probability of delivering at least
95% of the original prescribed dose (78Gy) to 99% of the target (prostate
gland and seminal vesicles) versus the rectal wall volume receiving morethan 65 Gy was analyzed using our evaluation tool (PD95V99,V65). The median results were compared, keeping the original clinical plans as reference[PD95V99=87%, V65=17%]. After the first optimization, planning with probabilistic objectives lead to better plans [PD95V99=87%, V65=16%] than standard planning [PD95V99=72%, V65=16%], obtaining higher target coveragewith similar rectal wall dosage (Fig.1).
Conclusions: Probability based treatment planning directly includes geometrical uncertainties during optimization without using explicit safety margins.
Plans obtained after one optimization run achieve acceptable dose-volume
metrics more often than those using standard objectives. This indicates apotential reduction in trial-and-error steps, i.e. even though probabilistic planning is computationally more demanding, the total planning time is likely to
reduce.

W EDNESDAY, M AY 11, 2011

P OSTERS 165

414 poster

415 poster

INTEGRAL DOSES IN NON-COPLANAR 3DCRT, LA-BASED IMRTAND HELICAL TOMOTHERAPY FOR SKULL BASE MENINGIOMAS
R. R. Upreti1 , A. Patil2 , T. Gupta3 , S. Kadam1 , D. Deshpande1 , R. Jalali2

ANATOMY DRIVEN OPTIMISATION OF GEOMETRICAL PARAMETERS IN MULTI-ARC AND MULTI-ISOCENTRES VOLUMETRICMODULATED ARC THERAPY TECHNIQUE FOR TOTAL MARROWIRRADIATION
P. Mancosu1 , P. Navarria1 , A. Fogliata2 , L. Castagna3 , F. Lobefalo1 , G.
Reggiori1 , S. Castiglioni1 , A. Santoro3 , M. Scorsetti1 , L. Cozzi2
1
I STITUTO C LINICO H UMANITAS, Department of Radiation Oncology,
Rozzano (Milan), Italy
2
O NCOLOGY I NSTITUTE OF S OUTHERN S WITZERLAND, Medical Physics
Unit, Bellinzona, Switzerland
3
I STITUTO C LINICO H UMANITAS, Department of Clinical Oncology, Rozzano(Milan), Italy

1

TATA M EMORIAL H OSPITAL, Medical Physics, Mumbai, India
TATA M EMORIAL H OSPITAL, Radiation Oncology, Mumbai, India
A DVANCED C ENTRE FOR T REATMENT R ESEARCH AND E DUCATION IN
C ANCER, Radiation Oncology, Navi Mumbai, India

2
3

Purpose: Radiotherapy for complex shaped skull-base tumours is challenging in view of their proximity to critical structures. Integral dose is a concern
in radiotherapy especially with high precision radiotherapy as it may lead toan increase in second malignancies. We present a dosimetric comparison of
3DCRT, LA-IMRT and Tomotherapy for these tumours in terms of target coverage, conformity, homogeneity, integral and mean doses to OAR’s & normal
tissues.
Materials: Image datasets of eight patients with residual skull-base meningiomas were considered for present analysis. PTV, OARs and normal tissues were delineated on co-registered CT-MRI images. Non-coplanar 3DCRT(P1), coplanar IMRT (P2), non-coplanar IMRT (P3) and helical Tomotherapy(P4) plans were generated using Eclipse8.6 and Tomotherapy TPS. Six toseven beams were used for all LA plans. For P1 and P3 gantry and couch
angles were kept same which was manually optimized for each patient tokeep maximum OAR’s projections out of BEV. Planning objective was kept
to achieve PTV coverage by 95% of prescription dose and minimal OAR’s
doses. The planning objective was kept same for all plans for fair dosimetric comparison. Dose prescription was 54Gy/30 fractions. DVH of PTV andOARs were generated to compute plan evaluation parameters including PTV
coverage (CI95% = VPTV95% /VPTV *100), conformity [conformity index =(VPTV95% /VPTV) * (VPTV95% /V95%)], homogeneity index (HI = D5% /D95%), mean doses and integral doses to OARs (ID = mean dose * VOAR)
and normal tissues (non-tumour integral dose ’NTID’).
Results: Mean (SD) PTV volume (cc) was 86.25±54.11 (range 17.52
180.11). All techniques achieved CI95% > 99%. Conformity index was most
optimal (0.80) with P2 and P4, both being 23% superior to P1 (0.65). Mean
HI of P4 (1.05) is comparable to P1 but found superior to both LA-IMRT plans.
Decrease of 11.2% in mean NTID (Gy-Lt) was observed in P3 (30.65±11.64)
over P1 (34.82±12.66). Mean NTID was 27.89±8.49 for P4. Mean NTID
was the lowest in P2 (23.52±8.08), however, P2 found worst among IMRT
plans for sparing critical OAR’s. The mean (SD) beam path length for P3
and P1 was 9.03±1.96 cm, for P2 and P4 it was observed 7.57±1.39 and8.14±1.81 cm respectively. Figure shows the integral doses and mean doses
to OAR’s. P4 achieved the maximal sparing of ipsilateral optic apparatus andbrain stem, however better sparing of contralateral optical apparatus was observed in P3 compared to other plans. Better sparing of temporal lobes wasobserved in P3, however P2 was found superior in sparing frontal lobes.

Purpose: To evaluate the possibility to optimize dose distribution for total
marrow irradiation employing volumetric modulated arc therapy (VMAT) with
the RapidArc (RA) technology by optimising the position of isocentres and ofjaws apertures based on anatomical features of patients.
Materials: Plans for five patients were generated with the RA engine(PROIII): 8 arcs were distributed along 4 isocenters and simultaneously optimized with collimator set to 90◦ . Two models were investigated for geometrical settings of arcs: (1) in the "natural" model isocenters were equispaced
and field apertures were set the same for all arcs to uniformly cover the entire target length. (2) In the "anatomy driven" both field sizes and isocentre
positions were optimised to minimize the target volume near to field edges,
i.e. to maximise the freedom of motion of MLC leaves inside the field aperture (for example avoiding arcs with ribs and iliac wings in the same BEV).
All body bones from the cranium to mid of the femurs were considered as
PTV, the maximum length achieved in this study was 130 cm. 12 Gy in 2
Gy/fraction were prescribed on the PTV and the plans were normalized atmean dose to PTV. For all organs at risk (including brain, optical structures,
oral and neck structures, lungs, heart, liver, kidneys, spleen, bowels, bladder,
rectum, genitals) planning strategy aimed to maximise sparing according to
ALARA principles aiming to reach a mean dose lower than 6-7 Gy.
Results: Figure 1 shows an example of the two different approaches. Mean
MU/fraction resulted 3184±354 and 2939±264 for the two strategies, corresponding to a reduction of 7% (range -2% to 13%) for (1) and (2). Target
homogeneity, defined as D2%-D98% was 18% better for (2). Mean dose to
the heathy tissue, defined as body minus PTV, had 7% of reduction with (2)better.

Conclusions: The isocenters position and the jaws apertures are significant
parameters to optimize the total marrow irradiation with RA technique, showing the the medical physicist crucial role for driving the optimization and thus
obtaining the best plan. A clinical protocol started in our department in October 2010.

Figure 1. Mean DVHs produced by the Monte Carlo evaluation tool for normal
and worst case scenarios. ArmA corresponds to the uniform dose escalation
to the target, armB corresponds to the dose boosting of the high FDG uptake
region.
Conclusions: Dose escalation techniques may benefit from probabilisticplanning. Increase in mean target dose is achieved both for conventionaldose escalation and dose painting techniques. For equal values of systematic and random errors probabilistic plans deliver higher dose to the target
compared to the standard margin based approaches. Probabilistic planningmight be a useful tool designing treatment plans for dose-escalation of lungtumors.

416 poster
COMPUTERISATION OF 2 STEP IMAT/IMRT SEGMENT GENERATION
M. Gainey1 , K. Bratengeier1 , M. Flentje1
1

J ULIUS -M AXIMILIANS U NIVERSITY, Department of Radiation Oncology,
Würzburg, Germany

Conclusions: Intensity modulation improves dose conformity and NTID compared with 3DCRT. Coplanar IMRT plans deliver the lowest integral dose to
the normal tissues. Non-coplanar IMRT plans achieved better sparing of contralateral optical apparatus, however delivered higher NTID compared to Tomotherapy and coplanar IMRT. Tomotherapy plans were superior in terms of
PTV coverage, homogeneity and overall sparing of OARs.

Purpose: 2-Step IMRT/IMAT are techniques which employ the topology ofplanning target volume(s), and organ at risk(s) to pre-define segment shapes
used in IMRT or IMAT. Previous work by our group has demonstrated thepotential to use 2-Step IMRT/IMAT as the basis for daily ad hoc plan adaption.
Hitherto the pre-definition of segment shapes was performed by manually
applying geometric rules. C++ software has been developed to automate thistime consuming process.
Materials: The Pinnacle3 (Philips, Fitchburg, WI, USA) treatment planningsystem (TPS) was used. All patient models were generated using a Somatom
CT scanner (Siemens Healthcare, Erlangen, Germany). The volume of interest (VOI) information for the relevant PTV(s) and OAR(s) was read into andS 166

P OSTER

processed by in house C++ software.For each gantry angle BEVs were determined for all PTVs and OARs. Each projection was stored as a binary arrayobject, mask, whose dimensions correspond to the maximum field size (inmm) of the multileaf collimator (MLC) for the TPS commissioned linacs.The
masks for each PTV-OAR pair were processed by combining Boolean anddilation operations to generate the zeroth, first and second order apertures(S0, S1 and S2). The resulting apertures were then sequenced into deliverable control point sequences and imported into the TPS to verify the accuracyof the S0,S1 and S2 segment shapes for each BEV.
Results: The algorithms have been tested using a number of tumour sites(parspinal, prostate and breast) to test the robustness and speed of the algorithms. The algorithm successfully generated IMRT and IMAT control point
sequences. A typical 9 field 2-Step paraspinal IMRT comprising 2 PTVs and1 OAR (spinal column) resulted in 81 segments generated in a total timeof 45s: pre-processing of the structure information (20s), mask generation(10s), mask processing (10s) and plan file generation and export to the TPS(5s). This compares favourably to the approximately 90 minutes necessary
for manual generation. A large number (on the order of 900 per PTV-OAR
pair) of segments are initially generated for IMAT plans which are filtered into
between one and three deliverable arcs, each comprising a maximum of 179
control points.
Conclusions: The computerisation of 2 Step IMRT/IMAT segment generation has been successfully tested for a range of tumour localisations: up to
three PTVs and three OARs, which should be sufficient even for complex
head and neck cases. The software is readily extendable to be compatible
with other TPSs and MLCs. 2 Step based treatment planning is moving towards the clinic.

W EDNESDAY, M AY 11, 2011

W EDNESDAY, M AY 11, 2011

Purpose: To compare the use of mean lung dose (MLD), mean perfusionweighted lung dose (MpLD) and mean dose to a functional lung region (rMLD)
in aperture-based IMRT for lung cancer with or without angle optimization.
Materials: For seven cases of lung cancer, treatment plans were optimized
with an aperture-based IMRT system. SPECT perfusion images were available for these patients. Prescription was 50 Gy to the CTV and 66 Gy to the
PTV2 with appropriate margins. A mean dose objective was included in thecost function for the lungs following three methods, either penalizing the MLD,
the MpLD or the rMLD of a region corresponding to 60% of the maximum
perfusion. Plans were composed of either seven equidistant beams or four
coplanar beams with optimized gantry angles. Various objective values were
explored in a multiobjective fashion until a plan with acceptable OAR doseand borderline adequate target coverage was obtained for each method.
Results: With seven equidistant beams, despite the explicit inclusion of
SPECT information in the optimization, no difference was obtained whencomparing the various methods. Mean variations in MpLD values were of-0.4 Gy (MpLD method, range -1.60.3) and -0.3 Gy (rMLD method, range 2.81.8) compared to the MLD method, with some plans actually doing worse
when including SPECT. Using only four gantry-optimized beams, we foundthat in six out of seven cases, values of MpLD decreased. Mean variationsin MpLD values were of -0.6 Gy (MpLD method, range -1.90.1) and -1.1 Gy(rMLD method, range -3.81.1) compared to the MLD method. Figure 1 shows
dose-volume and dose-function histograms for the PTV2 and lungs for one of
the cases, comparing the MLD and MpLD methods.

S 167

420 poster
THERMAL NEUTRON FLUENCY MEASUREMENT IN A HEAD AND
NECK PROTON THERAPY TREATMENT
J. I. Lagares1 , F. Sansaloni1 , J. A. Terrón2 , J. L. Muñiz1 , M. T. Romero
Expósito3 , J. J. Nieto-Camero4 , A. Korf4 , P. Arce5 , L. Núñez6 , M. Loubser4 ,F. Sanchez-Doblado78
1
CIEMAT, Medical Applications Unit, Madrid, Spain
2
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiotherapy Department,
Sevilla, Spain
3
U NIVERSIDAD DE S EVILLA, Fisiología Médica y Biofísica, Seville, Spain
4
I T HEMBA LABS, Medical Radiation Department, Somerset West, South
Africa5
CIEMAT, Basic Research, Madrid, Spain
6
H OSPITAL U NIVERSITARIO P UERTA DE H IERRO M AJADAHONDA, Radiophysics, Majadahonda - Madrid, Spain
7
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Fisiología Médica yBiofísica, Sevilla, Spain
8
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiotherapy, Sevilla,
Spain

Conclusions: This study showed that for fixed configurations of many coplanar beams, using any of the three methods does not lead to functional avoidance. However, including beam angle optimization in the process allows adecrease in MpLD. Functional lung avoidance efforts should therefore be focused on finding patient-specific beam configurations.

Conclusions: Using a fluence median filter during the optimization process
for IMRT planning allows considerably reducing the total amount of MU up
to 40%. Filter mask and size have substantial impact on the MU reduction
strength. If strong MU reduction for IMRT planning is desired, variable filter
mask is recommended, since it shows less adverse effects on min dose to
the PTV than mirrored- and crossed filter mask.

417 poster
FUNCTIONAL AVOIDANCE THROUGH MEAN LUNG DOSE AND
BEAM ANGLES OPTIMIZATION FOR LUNG CANCER IMRTJ. St-Hilaire1 2 , A. Dagnault1 , C. Lavoie1 , F. Beaulieu1 , F. Morin3 , L.
Beaulieu1 2 , D. Tremblay1 2
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Department of Radiation Oncology, Quebec, Canada
2
U NIVERSITÉ L AVAL, Department of Physics, Engineering Physics andOptics, Québec, Canada
3
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Department of Nuclear Medicine, Quebec, Canada

P OSTER

418 poster
MU REDUCTION FOR IMRT PLANNING WITH DIFFERENT FLUENCE MEDIAN FILTER STRATEGIES
A. Stoll1 , S. Nill1 , U. Oelfke1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Division of Medical
Physics in Radiation Oncology, Heidelberg, Germany
Purpose: Inverse planning for IMRT results in heterogeneous fluence distributions. Multiple segments are necessary to deliver the physical dose to apatient. The total amount of MUs increases, when a large number of small
segments are needed to build up the total dose distribution. Many methods toreduce the number of segments and amount of MU are proposed, e.g. intensity restrictions, smoothing procedures, beam modulation penalties or direct
aperture optimization. Incorporating a median filter strategy, into iterative gradient descent optimization, allows considerably reducing the amount of MU in
comparison to an unfiltered optimization process. As a drawback, strong filtering can cause adverse effects on the dose distribution and must always be
considered. This contribution evaluates eight fluence median filter strategies
for beamlet based inverse planning.
Materials: Median filter is chosen as a well known and non-parametric filtering strategy. One- and two-dimensional median filter masks are evaluated. Two-dimensional masks are encompassing four and eight element neighborhoods. Total MU reduction is evaluated for three prostatecases, with 7 beams at sequencing levels 3, 5 and 7, beamlet size 5x5mm for a 160 MLC and 76Gy prescribed dose to the PTV. Two onedimensional and six two-dimensional configurations, considering three masks
m={crossed,mirrored,variable} and two mask sizes s={3,5}, are evaluatedand compared to the unfiltered case: 1) Unfiltered. 2) 1D s=3. 3) 2D s=3
m=crossed. 4) 2D s=3 m=mirrored. 5) 2D s=3 m=variable. 6) 1D s=5. 7) 2D
s=5 m=crossed. 8) 2D s=5 m=mirrored. 9) 2D s=5 m=variable. 1D medianfilter and crossed mask are involving zero elements at the boundary of thefluence field. Mirrored mask is substituting zero elements with the mirrored
element along the central element and variable mask is entirely excluding
zero elements. As a measure of treatment plan quality, min dose to the PTV
is evaluated.
Results: This investigation shows that 2D median filtering is superior to 1D
median filtering, in respect of MU reduction, and is independent from sequencing level. Variable mask behaves worse in reduction of MU than mirrored mask, but, as an advantage, has less adverse effects on min dose to thePTV. It is observed that variable mask is superior, when increasing mask size
from 3 to 5. In mean, min dose for the PTV changes by 1.3% with variablemask, but 3.6% with mirrored- and 3.8% with crossed mask.

Young scientists ESTRO Poster Session: Radiation protection and dosimetry
419 poster
ESTIMATES OF DOSE TO PATIENT, SPOUSE AND RTT FROMAN IR-192 FIDUCIAL MARKER FOR USE IN EXTERNAL RT OF
PROSTATE CANCER
M. Hörling1 , T. H. Sørensen1 , D. Sjöström1 , P. F. Geertsen1 , C. F. Behrens1 ,B. H. Kristensen1
1
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Oncology,
Herlev, Denmark
Purpose: A positional system for radiotherapy based on a permanently implanted radioactive Ir-192 fiducial marker and a dedicated detector system
has recently been developed (Navotek Medical Ltd.). The system is planned
to be tested for set up of prostate patients and for monitoring inter- andintra-fractional motion of the prostate. The purpose of this study is to estimate the anticipated radiation dose from the marker to the patient, his
spouse/caretaker and the radiotherapy technicians (RTTs) involved.
Materials: Markers with a total activity of 15.8 MBq (427 µCi) were put into asmall tube inserted in an anthropomorphic body phantom (RANDO), approximately in the position of the prostate. An ion chamber survey meter (Fluke
Biomedical/Victoreen 451) was used to measure the dose rate at the bodysurface anterior of the prostate, as well as in distances of 0.5 m and 1.0 m
from the marker. The measured dose rates were scaled to correspond to an
implanted activity of 4.44 MBq (120 µCi), as this will be the maximum marker
activity at time of implantation. Using these dose rate values, and assumptions of occupancy and exposure time, worst case and likely annual wholebody doses to RTTs, and, in the case of the spouse/caretaker, whole bodydoses integrated from time of implantation to infinity were calculated.In orderto get rough estimates of the absorbed dose to the prostate and the effective
whole body dose to the patient, the MIRD formalism and S values for kidney
were used. The former was used as an indication of the dose received by
the parts of the rectum closest to the prostate, the rectum being the OAR ofprimary interest here.
Results: Measured dose rates (scaled to a 4.44 MBq implant activity) were22.4, 1.57 and 0.36 µSv/h at body surface, 0.5 m and 1.0 m, respectively.
The calculated worst case RTT annual whole body dose was 1.8 mSv. For the
likely case the value was 0.63 mSv. The worst case whole body dose to the
spouse/caretaker was 30.7 mSv, with a likely value of 2.0 mSv. The estimatedabsorbed dose to the prostate was 4.6 Gy and the estimated effective wholebody dose to the patient was 34 mSv.
Conclusions: None of the calculated doses indicate that the implantation of a 4.44 MBq Ir-192 fiducial marker in prostate cancer patients would
pose a dosimetric problem, neither for the staff, nor for the patient and his
spouse/caretaker. However, in order to reduce the dose to children, patients
will be restricted from having children in close proximity (e.g., sitting in the lapof the patient) during the first couple of months following the implantation.

Purpose: The evaluation of the neutron fluency in proton radiotherapy isgoing up in interest due to its contribution to the creation of second cancer,
as the patient longevity is increasing every year. In the present work weestimate the thermal neutron fluency distribution in a proton therapy headand neck treatment using an anthropomorphic NORMA phantom [1]. This
work is included into a more complex project to measure and characterize
the neutron dose contribution and to make a model to predict the risks.
Materials: TLD 600/700 couples were used to do the measurement. These
TLDs couples are commonly used to estimate the thermal neutron fluency
and the equivalent dose in a neutron field with energies below 20 MeV, thanks
to the different neutron nuclear reactions with 7 Li and 6 Li isotopes. In thepresent case, there are neutrons from thermal energies up to 200 MeV, produced by incident protons with a maximum proton maximum energy of 200
MeV. Nevertheless, Monte Carlo Simulations show that neutron production
with energy over 20 MeV constitute only a small fraction of the total neutron
production. Furthermore the cross sections on 7 Li and 6 Li for neutrons over
20 MeV decreases in an exponential way with the energy and they are negligible with respect to the cross sections for thermal neutrons [2]. The target
volume was defined as a cylinder of 3 cm diameter and 3 cm height. Two lateral opposed beams were used. The prescription dose was 10 Gy into the 90% isoline in the phantom. The TLD detectors were placed in 15 points inside
the NORMA phantom corresponding to different anatomical regions and oneout of the phantom, in the treatment room.
Results: The results obtained with the TLD pair method show a flux ranging
from 4.3106 n/cm2 at the pelvis medium to 3.3107 n/cm2 at the neck. Figure
1 shows the thermals neutron fluencies in all the points inside the anthropomorphic NORMA phantom and at the reference point in the room. We canappreciate the symmetry of thermal neutron fluencies at breasts, thorax andlegs, due the two lateral opposed irradiations used. The values decrease with
distance from the target volume. It can also be observed an increase of flux
with the proximity of the TLDs to the body surface, due to the absorption ofthermal neutrons present in the treatment room by the phantom material. To
estimate the neutron doses conversion factors of fluencies to organ equivalent doses in a phantom are needed, and until now they do not exist.

Conclusions: The results with the TLD pair method show that for proton
therapy treatments the neutron fluencies decrease with the distance from thetarget volume. The gamma doses delivered at different regions are no big.
1. Shez-Doblado, F, Domingo, C, G, F et al. On line neutron dose evaluation in patients under radiotherapy. In:Dssel O, schlegel WC, editors.

S 168P OSTERWC 2009, IFMBE Proccedings 25/I, Berlin: Springer. 2009;259-261.

2. A.J. Koning and D. Rochman.TENDL-2009: "TALYS-based Evaluated Nuclear Data Library".

421 poster
CALCULATION OF BRACHYTHERAPY BROAD BEAM TRANSMISSION FACTORS USING MC GENERATED MONOENERGETIC DATA*
K. Zourari1 , F. Ballester2 , D. Baltas3 , P. Papagiannis1 , J. Pérez-Calatayud4 ,W EDNESDAY, M AY 11, 2011
Mevatron, Primus, Oncor, Clinac, SL, Precise, Synergy). A new digitalneutron detector [1] was employed for measuring and performing an intercomparison under similar conditions.
Results: Due to the physical process in photo-neutron reaction, simulated
and experimental spectra agree, and similar relative shapes are obtained independently of the energy and manufacturer. The only difference is the absolute value of the neutron fluence, which is very well related with the electronic
signal of the digital device (events). Figure 1 shows the behaviour for the setof accelerators studied (different Varian Clinac models have been grouped
due to similar results).

J. Venselaar5
M EDICAL S CHOOL , U NIVERSITY OF ATHENS, Medical Physics Laboratory,
Athens, Greece
2
U NIVERSITY OF VALENCIA -IFIC, Valencia (Paterna), Spain
3
K LINIKUM O FFENBACH G MB H, Offenbach am Main, Germany
4
H OSPITAL U NIVERSITARIO L A F E, Valencia, Spain
5
D R . B ERNARD V ERBEETEN I NSTITUUT, Tilburg, Netherlands
1

Purpose: MC simulation has been previously used to generate radiationtransmission data of photon radiation emitted from various radionuclides
through various materials, in an effort to address the limited availability ofradiation shielding data for brachytherapy as well as some disparity in existing data. Since new radionuclides are continuously investigated for use inbrachytherapy applications, this work aims at evaluating a method to calculate the broad beam radiation transmission data for any poly-energetic photon
source, using corresponding MC simulation generated data for monoenergetic photon sources.
Materials: The MCNP simulation code was employed for the calculation ofpoint source, monoenergetic photon radiation transmission data though leadand concrete, in the energy range of 10 to 670 keV, in 10 keV intervals. The
simulation geometry comprised the broad beam simulation geometry presented in a previous work [Med. Phys. 35, 4898, 2008]. All other simulation details were also identical. The resolution of barrier thickness for eachenergy-material combination was adjusted so that three values were calculated per order of magnitude of transmission reduction, down to 104 . The
3-parameter model introduced by Archer et al. [Health Phys. 44, 507, 1983]
to facilitate diagnostic x-ray shielding calculations was fit to the MC results ofthis work. The method presented by Kharrati et al. [Med. Phys. 34, 1398,
2007] was then adopted for the calculation of transmission factors for actual
polyenergetic photon emitting radionuclides used in brachytherapy. Results
were compared to corresponding data for the actual polyenergetic beams obtained by MC simulations in the previous work using the same methodology.
Results: Overall, analytically calculated transmission data of this work were
found in good agreement with corresponding MC simulation results, regardless of the radionuclide effective energy and material. As expected, agreement deteriorates with increasing material thickness remaining however adequate for radiation shielding calculation purposes.
Conclusions: The proposed method for the combination of monoenergetic
photon transmission data to arrive at corresponding data for any polyenergetic photon source is found efficient for structural radiation shielding calculations in brachytherapy. * Work performed within the framework of the
GEC-ESTRO working group BRAPHYQS (brachytherapy physics quality assurance system) physicist’ network
422 poster
COMPARISON OF PHOTO-NEUTRON FLUENCE FOR DIFFERENTENERGIES, MANUFACTURERS AND MODELS OF LINACS.
M. T. Romero Exposito1 , F. Sanchez-Doblado1 2 , J. A. Terrón2 , C.
Domingo3 , K. Amgarou3 , M. J. Garcia-Fuste3 , X. L. González Soto4 , J. I.
Lagares5 , F. Gomez4
1
U NIVERSIDAD DE S EVILLA, Departamento de Fisiología Médica y Biofísica,
Seville, Spain
2
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiofisica, Sevilla, Spain
3
U NIVERSITAT AUTÒNOMA DE B ARCELONA, Physics, Cerdanyola, Spain
4
U NIVERSIDADE DE S ANTIAGO DE C OMPOSTELA, Particle Physics, Santiago
de Compostela, Spain
5
CIEMAT, Madrid, Spain
Purpose: Neutron contamination in radiotherapy using photon beams over
10 MV could represent an important drawback for patients under treatment,
due to the increase of probability of acquiring a long term second cancer.
The majority of these particles are generated in the head of the linac. In consequence, manufacturers have a significant responsibility in designing andselecting components to reduce as much as possible the unwanted extra
peripheral dose in the patient. For this purpose, some comparative measurements have been performed, considering almost all types of operative
machines in the world.
Materials: Spectra, obtained both from Monte Carlo simulation and experimentally using boner spheres with gold activation foils, have been obtainedor estimated at the isocentre for different photon energies (15-23 MV), manufacturers (Varian, Siemens, Elekta, General Electric) and models (Saturne,

W EDNESDAY, M AY 11, 2011
factors of 6 MV small fields ii) Beam profiles of cobalt 60 narrow fields and iii) 6
MV intensity modulated radiotherapy (IMRT) segments.The two-dimensional
RF of a PTW 30013 IC was obtained by MC simulation of the absorbed doseto cavity air when the IC was scanned by a 0.6 x 0.6 mm2 cross section parallel pencil beam. In these simulations the IC laid horizontally in a water tankat 1 cm depth. Two pencil beam spectra were considered i) A monoenergetic
1.25 MeV beam and ii) that obtained for a 0.5 x 0.5 cm2 field delivered by a 6
MV Siemens PRIMUS.Fluence distributions for small fields ranging between
0.5 x 0.5 and 10 x 10 cm2 and delivered by a 6 MV Siemens PRIMUS wereobtained by MC simulation.Fluence distributions for 1.4 x 1.4 and 3 x 3 cm2fields and delivered by a MLC-equipped AECL Theratron Cobalt 60 unit were
determined by diode measurements.Fluence distributions for 6 MV IMRT clinical segments were obtained by radiochromic film dosimetry measurements
and Treatment Planning System (TPS) calculations. For each of the cases
studied, the results of the IC direct measurement were compared with thecorresponding obtained by the C/S method.
Results: For all of the cases studied, the agreement between the IC direct
measurement and the IC calculated response was excellent. The relative
deviation between both responses was below 0.8% in the cases of 6 MV
small field output factors (as it can be seen in figure 1) and cobalt 60 narrow
beam profiles. In the case of IMRT segments the relative deviation was below
1%.

P OSTER

S 169

acquired varying the polarization voltage from 400V to 800V in 50V steps. An
Ir-192 source was used during the continuous beam experiment. The source
had a dose rate of 5.98 cGy/min at 10 cm with a varying polarization voltage
ranging from 400 to 800 V in 50 V steps.
Results: The microLion chamber demonstrated a linear relationship (slope =0.2%/o K) as a function of temperature for both the 400 and 800V polarization
voltages. The polarization effect study showed a polarization < 1.0% for bothpolarization voltages with a stem effect of .3% for the 400V and .8% for the
800V. In the general, recombination effect demonstrated a linear relationshipat polarization voltages higher than 600 V and a dropping curve with voltages
lower than 600 V in both delivered modes: pulse and continuous beam.

Conclusions: The microLion ionization chamber demonstrated a linear dependence with increase temperature which is consistent with the theoreticalmodel based on the Onsager theory. The polarization effect study showed
percent differences of less than 1.0% in both polarization voltages and thegeneral recombination effect showed similar response to previously publisheddata on the isooctane liquid used in different geometries.

Conclusions: As expected, higher values are obtained for higher photon
beam energy. In addition, linac manufacturer is an important factor in which
dose depend on. Highest doses were obtained in Varian accelerators andlowest, in Elekta. Besides, we have observed also that new models of
Siemens (Oncor) and Elekta (Synergy) linacs seem to produce smaller neutron contributions, with lower values of doses with respect to the previous
versions.[1] G F, Iglesias I and Sanchez-Doblado F. A new active method forthe measurement of slow-neutron fluence in modern radiotherapy treatment
rooms. Phys Med Biol 2010;55:10251039. The authors are indebted to the
University Law (LOU) contract between the University of Seville and the Andalusian Health Service (SAS) and especially to the Spanish Nuclear Security Council (CSN). Experimental measurements would have been impossible without the kind collaboration of a huge number of medical physicists andtechnicians in the hospitals selected for the study.
423 poster
CONVOLUTION MODEL AS AN ALTERNATIVE TO FULL MOTECARLO DERIVED CORRECTION FACTORS FOR THE DOSIMETRY
OF NON STANDARD FIELDS
D. M. González-Castaño1 , L. Brualla-González2 , G. A. Araceli1 , J. Pardo
Montero1 , F. Gomez1 , F. Sanchez-Doblado3
1
U NIVERSIDADE DE S ANTIAGO DE C OMPOSTELA, Departamento de Física
de Partículas, Santiago de Compostela, Spain
2
ERESA, H OSPITAL G ENERAL U NIVERSITARIO, ERESA, Valencia, Spain
3
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Departamento de
Fisiología Médica y Biofísica, Sevilla, Spain
Purpose: This work contains an alternative for obtaining correction factors
for ionization chamber (IC) dosimetry of small fields and also an alternative tothe use of correction factors in composite fields. The method is based on the
convolution/superposition (C/S) of an IC response function (RF) with energy
fluence distribution. This method is an alternative to full Monte Carlo (MC)approach
Materials: The response of an IC at a point inside a phantom irradiated by acertain beam can be obtained as the convolution of the fluence spatial distribution caused by the beam and the IC two-dimensional RF.This method wasapplied to predict the response of a PTW 30013 IC when measuring: i) Output

Figure 1. Comparison between direct measurement (full squares) and calculated response of output factors (void squares) for a PTW 30013 IC.
Conclusions: This method could be implemented in TPS in order to perform
an experimental IMRT treatment verification with in-phantom ionization chamber measurements. The miss-response of the IC due to the non-reference
conditions could be corrected by this method rather than employing MC derived correction factors. This method can be considered as an alternative tothe plan-class associated correction factors proposed in Alfonso et al Med
Phys 35 (11) 2008 as part of an IAEA work group on non-standard field
dosimetry.
424 poster
CHARACTERIZATION OF THE TEMPERATURE, POLARIZATION,
AND ION RECOMBINATION FOR THE MICROLION LIQUID IONIZATION CHAMBER
A. Gutierrez1 , S. Stathakis2 , N. Papanikolaou2
1
U NIVERSITY OF T EXAS H EALTH S CIENCE C ENTER /C ANCER T HERAPY AND
R ESEARCH C ENTER, Department of Radiation Oncology, San Antonio, USA
2
C ANCER T HERAPY, San Antonio, TX, USA
Purpose: To study the temperature, polarization and general recombination
effects of the PTW microLion ionization chamber.
Materials: Measurements were performed on a Clinac 2300C 80MLC linear
accelerator. The MP3-XS water phantom (PTW, Hicksville, NY) which integrates the detector positioning TRUFIX was used during all measurements.
The temperature dependence of the ionization chamber was done by varying the water temperature in two degree steps from the reference of 295o K
down to 286o K and up to 301o K. Five consecutive measurements with a 6MV
photon beam and two different polarizing voltages (400V and 800V) were acquired at each temperature increment. The polarization effect was performedby irradiating the microLion with a 9 MeV electron beam as a function of
depth and for two different polarization voltages (400/800V). The general recombination effect was done for pulse and continuous beam. In the first case,the pulse repetition frequency (PRF) of the linear accelerator was set at 30
pulses/sec for an 18MV beam and 60 pulses/sec for a 6MV beam and a pulse
length of 3.7 µs in both cases. Three different doses per pulse were used ineach case. For the 6 MV beam, the three doses per pulse were: 0.023,
0.0175 and 0.012 cGy/min, while for the 18 MV beam the doses per pulse
were 0.046, .035 and .023 cGy/min. Five consecutive measurements were

425 poster
BIOPHYSICAL ESTIMATION OF DNA DAMAGE AND SECONDCANCER RISK USING GAMMA H2AX AND TLDS IN PROSTATECANCER IMRTO. Chan1 , M. Hussein2 , M. Worku3 , R. Laing1 , T. Jordan2 , H. Pandha4 , R.
Morgan4 , S. Short3 , A. Nisbet2 , T. Guerrero Urbano1
1
S T L UKE ’ S C ANCER C ENTRE , R OYAL S URREY C OUNTY H OSPITAL,
Guildford, United Kingdom
2
T HE R OYAL S URREY C OUNTY H OSPITAL NHS F OUNDATION T RUST,
Department of Medical Physics, Guildford, United Kingdom
3
UCL C ANCER I NSTITUTE, London, United Kingdom
4
U NIVERSITY OF S URREY, Postgraduate Medical School, Guildford, United
Kingdom
Purpose: IMRT is reported to be associated with a higher risk of second
cancer compared to conformal RT. It can potentially double the risk due tothe increased volume of normal tissue receiving low doses and increased
scatter radiation and leakage from longer beam on times.This risk is potentially higher in patients treated with higher energy beams, generally used totreat deep seated tumours.Phosphorylated H2AX (gamma H2AX) is an earlycellular response to DNA double strand break formation and can be used toquantify radiation induced DNA damage.It could potentially be used as a surrogate marker for second malignancy as some studies have suggested thatlevels increase linearly with radiation dose.The aim is to evaluate DNA damage and dosimetric parameters with changes in beam energy and treatedvolume.
Materials: 20 patients with prostate cancer were treated with IMRT, with
5 patients per group: Prostate (74Gy/37F-6MV, 57-60Gy/19-20F-6MV, 5760Gy/19-20F-15MV), Prostate and nodes (74Gy/37F-6MV).Pre- and 30 minutes post-irradiation venous samples were taken to assess DNA damage atplanning CT, F1, F2, midway and end of RT, plus at week 10.Clinical IMRT
plans were delivered to a phantom containing thermoluminescent dosimeters.Organ equivalent doses and effective dose were calculated using tissue
weighting factors from International Commission on Radiological Protection
103.The effective dose was used to estimate the theoretical age-corrected
lifetime risk of second cancer.
Results: At least 300 cells were counted from each of the 189 samples.Across all patients, the mean baseline gamma H2AX level was 0.033(SD=0.012) and recovery at 10 weeks was observed, with mean 0.037

S 170P OSTER(SD=0.014), p=0.505. When analysed for each group, there was a trend towards incomplete recovery in the 15MV group (p=0.113).Comparisons weremade between the standard 74Gy prostate only group and the 3 other groups
for mean difference between post- and pre-irradiation levels. There was no
significant difference between the groups at any time point. There may be
a trend towards increased difference at the end of RT in prostate and nodes
compared to 74Gy prostate only (0.048 compared to 0.032, p=0.158).Similar
comparison was made for effective dose and it was found to be significantly higher for prostate and nodes (p=0.041) and slightly lower for 15MV
(p=0.071). However, this did not translate to a difference in age-correctedrisk.

W EDNESDAY, M AY 11, 2011

W EDNESDAY, M AY 11, 2011

426 poster
DEVELOPMENT OF AN A-SI EPID-BASED SYSTEM FOR MACHINE,IMRT AND VMAT QUALITY ASSURANCE
L. A. Vazquez-Quino1 , X. Chen1 , M. Fitzpatrick1 , C. Shi1 , P. Mavroidis2 , H.
Alkhatib3 , D. Mihailidis4 , N. Papanikolaou1
1
CTRC @ UT HSC AT S AN A NTONIO, San Antonio, USA
2
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Stockholm,
Sweden3
S OUTH C AROLINA O NCOLOGY A SSOC., Columbia, USA
4
C HARLESTON R ADIATION T HERAPY C ONS, Charleston, USA

Conclusions: Gamma H2AX is potentially a promising biological dosimetry
marker to add to physical parameters used to provide estimates of second
cancer risk with IMRT.There is a trend towards incomplete recovery at week
10 with 15MV, but with possibly lower effective dose.This could be due toimproved dose at depth with 15MV, as well as possible limitations of the small
study number, laboratory technique and phantom measurements.Increased
numbers are required to draw further conclusions.

S 171

Results: The accuracy with which an error in MLC position was detected depended on the location of the error relative to the detectors in the matrix. In
some locations, the method creates blurring of the reconstructed dose (figure1). For leaf positioning errors from 1 to 5 mm, the reconstructed dose in an
individual rectangular field was correct within 3% in at least 50% of the locations. The reconstructed dose showed maximum inaccuracies of 8% in asmall area (10x10 mm2 per leaf) close to the erroneously positioned leaf. Position inaccuracy of the field edge never exceeded 2 mm. The mean gamma
provided by the system was on average correct, although a variation depending on the location of the field edge existed. The number of points above
gamma 1 was sufficiently accurate to ensure error detection for QA purposes
at 762 mm SDD. Using the detector at 1000 mm SDD increased the dose
blurring effect of the correction kernel, which affects the sensitivity for QA
purposes by decreasing the number of points above gamma 1.

Young scientists ESTRO Poster Session: IMRT
Verification and QA

Purpose: The increasing prevalence of amorphous-silicon (a-Si) electronic
portal imaging devices (EPID) for in-line verification imaging, has led toheightened interest in applying EPID based dosimetry to machine and patient quality assurance (QA). As such, EPID dosimetry offers the potential tofill a useful role when verifying intensity modulated radiotherapy (IMRT) andvolumetric arc therapy (VMAT) treatment plans. The purpose of the present
study is to validate the development of an in-house software using an EPID
measured beam fluence for IMRT and VMAT QA.
Materials: EPID images are acquired by directly irradiating an aS1000 EPID
in the following two acquisition conditions: 1) Using an integrated image acquisition mode, for a 6 MV beam, 600 MU/min dose rate with an IMRT planand; 2) Using a continuous image acquisition mode, for a 6 MV beam, 600
MU/min dose rate with a VMAT plan. Signal intensity of the EPID images areconverted to a planar dose map using a calibrated linear signal-to-dose relationship. Using an in house QA software system we analyze the EPID-based
fluence images. For routine machine QA, recommendations by TG-40 and
TG-45 AAPM reports are implemented to evaluate beam flatness/symmetry,
perform dynamic MLC validation and perform a Wiston-Lutz isocenter test.
For IMRT and VMAT QA, the fluence maps are reconstructed from the EPIDmeasured fluence and serve as input to the treatment plan system. The treatment planning system is then used for dose calculation and trial comparison
between the measurement and the plan.
Results: EPID-measured machine QA results are comparable to film measurements for the Winston-Lutz isocenter test, beam flatness and symmetry along with checks of dynamic MLC treatment profiles. Figure 1 shows
the comparison of the calculated dose using EPID-measured fluence to theplanned dose for IMRT and VMAT. The EPID based IMRT and VMAT QA
method was able to verify the treatment plan and demonstrates a good planversus-QA comparison with a gamma analysis (3% maximum dose, 3 mmdistance to agreement) resulting in over 99 % of points with a gamma <1 asshown in figure 1. Point dose between EPID and Ion chamber measurements
for IMRT plans were on average within 2% for 20 plans of different treatmentsites.

P OSTER

Figure 1: Comparison of EPID-based QA dose (left) to plan dose (right); a)
Head and neck IMRT plan comparison, b) Prostate VMAT plan.
Conclusions: Our results show that EPID may be used as a tool for clinical
QA tasks and the implementation of an EPID-based QA system for machine,
IMRT and VMAT QA. Our method for EPID IMRT and VMAT QA uses theplanning system itself for volumetric dose calculation and comparison with theclinical plan. The dose is recalculated in the patient image and is reflectiveof the true dose given tot eh patient based on the measured fluence maps.
(Research sponsored by Oncology Data Systems, Inc, Oklahoma City, OK)
427 poster
RECONSTRUCTION OF HIGH RESOLUTION 3D DOSE FROM LOWRESOLUTION MATRIX MEASUREMENTS: A CORRECTION KERNELMETHOD
J. Godart1 , E. Korevaar1 , R. Visser12 , D. Wauben1 , A. van ’t Veld1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Oncology, Groningen, Netherlands
2
R ESEARCH AND I NNOVATION G ROUP IN H EALTH C ARE AND N URSING/ H ANZE U NIVERSITY OF A PPLIED S CIENCES, Medical Imaging andRadiotherapy, Groningen, Netherlands
Purpose: 2D ionization chamber arrays are increasingly used for IMRT quality assurance, but they suffer from a low spatial resolution which limits theircapability to check with high resolution the fluence coming from a linear accelerator. The COMPASS system, from IBA Dosimetry, uses a fluence reconstruction method which aims to overcome this disadvantage and allows
3D dose reconstruction in the patient CT. However, the implemented fluence
reconstruction uses a correction kernel method that introduces inaccuracies
in the 3D dose reconstruction. The purpose of this work was to quantify
the dosimetric accuracy of the COMPASS correction kernel method and to
determine its ability to detect dose delivery errors caused by MLC leaf mispositioning.
Materials: This work was based on a comparison between two COMPASS
dose reconstruction situations for a single delivery that included leaf positioning errors: the first reconstruction was done with the nominal dicom RT plan
(which did not show the introduced errors), and the second with a plan inwhich the position of the leaves was corrected according to the real delivery(including introduced errors). Measurements were done at an Elekta Linac at
6MV, equipped with a MLC with 10 mm leaf width. The MatriXX evolution wasused with Source Detector Distances (SDDs) of 762 and 1000 mm. A totalof 425 dose reconstructions were performed for MLC position errors of various sizes (1 to 10 mm) at various locations in the field, for both rectangular
and IMRT fields. The QA capability of the system was tested for every casethrough gamma evaluation, with 3%/3 mm criterion.

Conclusions: The correction kernel method used by the COMPASS system
is an adequate tool to perform accurate QA of IMRT treatment plans with aregular MLC, despite local inaccuracies in the dose reconstruction.

S 172

P OSTERW EDNESDAY, M AY 11, 2011

W EDNESDAY, M AY 11, 2011428 poster

429 poster

430 poster

EMPIRICAL CHARACTERIZATION OF A SILICON STRIP DETECTOR
FOR A NOVEL 2D MAPPED METHOD FOR DOSIMETRIC VERIFICATION OF RADIOTHERAPY TREATMENTS
A. Bocci1 , M. I. Gallardo2 , J. M. Espino2 , R. Arráns3 , Z. A. Haidara1 , M.
A. G. Alvarez2 , M. A. C. G. Cortes Giraldo2 , J. M. Quesada2 , A. Perez
Vega-Leal4 , F. J. Pérez Nieto5
1
C ENTRO N ACIONAL DE ACELERADORES, Seville, Spain
2
U NIVERSITY OF S EVILLE, Department of Atomic, Molecular and Nuclear
Physics , Seville, Spain
3
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Sevilla, Spain
4
U NIVERSITY OF S EVILLE, Higher Technical School of Engineering, Seville,
Spain
5
I NSTALACIONES I NABENSA S.A., Spain

AN EFFICIENT AND INDEPENDENT 3D DOSE CALCULATIONTOOL FOR QUALITY ASSURANCE OF COMPLEX RADIOTHERAPYTREATMENT PLANS
R. Visser1 2 , J. Godart1 , D. Wauben1 , A. van ’t Veld1 , E. Korevaar1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Oncology, Groningen, Netherlands
2
R ESEARCH AND I NNOVATION G ROUP IN H EALTH C ARE AND N URSING/ H ANZE U NIVERSITY OF A PPLIED S CIENCES, Medical Imaging andRadiotherapy, Groningen, Netherlands

CLINICAL COMMISSIONING OF RAPIDARC TREATMENT TECHNIQUE IN VARIAN UNIQUE LINEAR ACCELERATOR
S. K. Chan1 , K. Y. Lee1 , M. L. M. Cheung1 , M. C. Chau1 , K. Y. Cheung1
1
P RINCE OF WALES H OSPITAL, Clinical Oncology, Hong Kong, Hong Kong
(SAR) China

Purpose: Dose distribution verification is highly advisable prior to real dosedelivery to patient for IMRT treatments. In fact, the increasing sophisticationand complexity of IMRT treatments is a major challenge for Treatment Planning Systems (TPS) which might miscalculate under some circumstances.
Usually, radiochromic films are used for IMRT treatments verification. Nevertheless, this dosimeter has the main drawback of its unavoidable delayed
reading process, that makes it unsuitable an on line detector. Recently, 2D
arrays based on silicon diodes or ion chambers have been developed andused as on line detectors. However, the higher spatial resolution and the possibility of measuring dose maps in axial planes is still a major advantage offilms with respect to 2D arrays.
Materials: In this work we present the characterization of a silicon DCcoupled single-sided strip detector (SSSSD) from Micron Semiconductor Ltd.
irradiated with a Siemens PRIMUS linac at 6-MV photon mode. The SSSSD
has 16 strips 500 µm thick, 3.14 mm pitch each covering an area of 50.0 x
50.0 mm2 . This work is part of a more ambitious project aiming to validatea novel method for measuring axial dose maps in IMRT treatments. Twophantom prototypes have been designed for the detector characterizationand treatment verification: a water-equivalent slab phantom with the detector placed perpendicular to the beam direction and a quasi-anthropomorphic
cylindrical phantom with the capability of rotating along its symmetry axis.
The cylindrical phantom has the detector placed perpendicular to its symmetry axis (see figure). This situation is close to conditions normally foundin clinical environments, where dose distributions are normally presented asdose maps in the patient axial plane. Despite its spatial resolution limitations,
the SSSSD is a cheaper solution for studying the pros and cons of this semiconductor technology for providing a novel method for using it as treatment
verification system. Geant4 simulations and TPS calculations for both phantoms have been performed and comparison to experimental data has been
carried out.

Results: Measurements showed that the linearity of the device is remarkablewithin 0.5 %. The concordance of the PDD with respect to an ion chamberis within 1 %. The penumbra shows a value higher with respect to a silicon
diode (6 mm versus 4 mm), probably due to the strip pitch of the SSSSD. The
angular response of the detector has been also studied and comparisons toGeant 4 and TPS calculations are in good agreement.
Conclusions: Final results show that the behavior and the characteristics ofthe detector are acceptable for verifying the reliability of a 2D reconstructionof specific radiotherapy treatments. Further improvements in the spatial resolution of this method could be obtained using a SSSSD with a smaller strip
pitch, or with a pixellated system.

Purpose: The importance of efficient QA tools for radiotherapy treatments
grows due to the increasing number of complex treatment plans. The COMPASS system (IBA Dosimetry) is a QA tool that offers 3D dose determination
in a patient CT by a model based calculation or a measurement based reconstruction. Combination of the two methods can lead to a QA procedure thatprovides the required increase in efficiency. The model based calculation isused in the clinic as an independent verification of the TPS calculated doseby gamma index (GI) and dose volume histogram (DVH) evaluation. The purpose of this study is to validate the model based 3D dose calculation and toevaluate the efficiency of the combination of model based and measurement
based 3D dose reconstruction.
Materials: The first part of the study focussed on the validation of 3D dose
calculations in homogeneous and inhomogeneous media using water phantom measurements and Monte Carlo (MC) simulations as reference, respectively. Water phantom measurements (output factors, depth dose curves andprofiles) were obtained for rectangular field sizes ranging from 3x3 to 39x39
cm2 for a 6MV photon beam on an Elekta Synergy machine and these werecompared to COMPASS (v1.2) computations. A linac model was createdin BEAMnrc (2010) and dose calculations were computed with DOSXYZnrc(2010) for artificially created CT phantoms that contained either a low density region (0.25 g/cm3 ) or various cylinders with higher densities (1.202.70g/cm3 ). The second part of the study evaluated the use of COMPASS for
210 clinical IMRT treatment plans created with Pinnacle (v8.0h). Each treatment plan was imported into COMPASS for an independent 3D dose checkincluding a gamma analysis with criteria of 3%/3mm and DVH comparison
for organs at risk (OAR) and PTVs. For DVH doses exceeding DVH specificdose limits, the treatment plan was evaluated by a radiation oncologist and/or
analysed using a measurement based dose reconstruction. Monthly measurement based QA was performed with COMPASS for head and neck IMRT
treatments to verify correct behaviour of the linac over time.
Results: COMPASS computed dose showed good agreement with water
phantom measurements and MC dose calculations in homogeneous andinhomogeneous media. Dose differences were within clinical criteria of
3%/3mm.On average the 210 clinical treatment plans showed good agreement with Pinnacle with a mean GI of 0.28 ±0.06 (figure 1). Higher GI values
corresponded to higher doses in the OAR or PTVs calculated by COMPASS.
Seventeen treatment plans showed exceeding OAR or PTV doses which wereapproved after an evaluation by the radiation oncologist or an extra measurement based dose reconstruction. The model based QA procedure was on
average completed within 10 minutes and a measurement based QA within
30 minutes. Regular measurement based QA showed correct behaviour ofthe linac with a mean GI of 0.31±0.04 over one year.

Conclusions: COMPASS is suitable to verify the TPS calculated 3D dose forcomplex treatment plans. The model based QA procedure is more efficientthan measurement based QA, and, in combination with regular measurement
based QA, correct behaviour of the linac is verified over time.

Purpose: To verify the dosimetric and geometric accuracy of a Volumetric
Intensity Modulated Arc Therapy (VIMAT) system delivered by a new modelof linear accelerator (Varian UNIQUE).
Materials: Two head-and-neck, and one prostate cases were selected in thisinvestigation. The equipment under test was a Varian UNIQUE linear accelerator with 6MV single photon energy operating in RapidArc mode. The patientplans for these 3 cases were transferred to a cylindrical perspex round phantom for dosimetric measurement. The multi-point dose measurement was
performed using ionization chambers to verify the dose delivery and the relative dose map measurement was done with film dosimetry. For the mechanical performance, the system log files (Dlog and Dynalogs) were extracted
from treatment control system and reconstructed for analyzing the accuracyof the MU delivery against gantry angle and MLC leaf positions at each control point. An independent inclinometer was installed inside the gantry tomonitor the gantry trajectory and verify the digital readout of gantry angle. A
Ficket-Fence test in Arc mode was done to verify the MLC leaf position. Integrated Transient Fluence Map (ITFM), an IMRT-like fluence map, was generated from the system log files and was introduced to check the fluence map
in a rotating frame (it was in analogy to exposure of film mounted on gantry
head in an arc treatment).
Results: For the dosimetric measurement, the planned and measured pointdoses showed a good agreement, with a maximum deviation of +/- 2%. The
isodose distribution from Treatment Planning System (TPS) and film agreed
well at the 80, 90 and 95% isodose levels, with a mean distance-to-agreement
less than 1mm. For the mechanical performance, the analysis of the log files
indicated that the average discrepancies of the delivered MU and gantry angle were 0.05 MU and 0.50 respectively. The angular trajectory of the inclinometer was in good agreement with the digital readout of gantry angle andthe Ficket-Fence pattern showed the discrepancy of MLC leaf position within
only +/- 0.5mm. In addition, the correlation coefficient of planned and measured ITFMs was in average 0.9997 (close to unity) and the image subtraction
between them showed negligible difference.
Conclusions: The dosimetric and geometric accuracy of RapidArc treatment
delivered by Varian UNIQUE has been verified and commissioned for clinicalservice. High quality conformal radiotherapy treatment can be delivered withthis technique in a much shorter time than that using conventional IMRT technique.
431 poster
CHARACTERIZATION OF A NEW WATER-EQUIVALENT 2D DETECTOR ARRAY FOR THE DOSIMETRY OF IMRT PLANS
M. Guillot1 , L. Gingras1 , L. Archambault1 , S. Beddar2 , L. Beaulieu1
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Quebec, Canada
2
U.T. M.D. A NDERSON C ANCER C ENTER, Houston, TX, USA
Purpose: This work aims to evaluate the ability of a new 2D detector array toaccurately measure complex dose distributions such as those encountered in
IMRT.
Materials: We developed a new 2D detector array for the dosimetry of megavoltage energy photon beams for radiation therapy. The 2D-array consists in
781 plastic scintillation detectors (PSDs) inserted in a plane of a 3x30x30 cm3plastic water slab. The PSDs are spaced 10 mm apart, except for two central
perpendicular lines where the detector spacing is 5 mm. The total detection
area is 26x26 cm2 . The plastic water containing all the PSDs is fixed in a
specially designed acrylic water tank. The sensitive volume of each PSD is
made of a small polystyrene scintillator of 1 mm diameter and of a length of 3
mm (BFC-12, Saint-Gobain Inc., Paris, France). The scintillators are coupled
to clear plastic optical fibers to guide the scintillation light produced toward a
photodetector. An optical system was designed to read simultaneously all the
PSDs at a rate of one measurement per second with no dead time between
each measurement. To assess the ability of the device to measure complex
dose distributions, a clinical head and neck IMRT plan was delivered to the
2D-array. The plan was composed of six beam incidences (0◦ , 103◦ , 257◦ ,309◦ , 165◦ and 195◦ ), each beam being composed of five or seven segments. The IMRT plan was first delivered by keeping the gantry angle fixedat 0◦ . This allows to eliminate possible errors caused by deviations in thegantry angle, phantom corners intercepted by the incident beams and gravity
effects on the MLC. In a second step, the plan was delivered with the planned
gantry angles. The dose distributions of the IMRT plan were calculated on aCT-scan of the 2D-array using a treatment planning system (Pinnacle3 Version 8.0m, Philips Medical Systems, Andover, MA, USA). The measured dose
distributions were compared to the planned one by using a gamma evaluation
with dose tolerances expressed as a percentage of the maximum dose in thedetection plane and a distance to agreement of 3 mm.

P OSTER

S 173

Results: For all beams of the plan delivered at fixed gantry angle 0◦ , thepassing rate of the evaluation (2% or 3 mm) was superior to 99.0 % when
all the PSDs were considered and superior to 97.7 % when only the PSDs
located in the high dose region (doses > 50 % of the maximum dose) wereconsidered. The results from the gamma evaluation (3% or 3 mm) are presented in TABLE I for the case where the plan was delivered with the planned
gantry angles. The average passing rate was 98.2 % when all the PSDs wereconsidered and 97.6 % for the high dose region.

Conclusions: A good agreement was obtained between the measured andplanned dose distributions. These results suggest that the developed 2Darray could potentially be used to perform accurate dosimetric verification of
IMRT plans.
432 poster
VALIDATION OF TWO DOSE DELIVERY VERIFICATION METHODSFOR IN-VIVO DOSIMETRY IN HELICAL TOMOTHERAPY
C. Lesven1 , S. Caneva2 , A. Mazal1 , P. Francois1
1
I NSTITUT C URIE, Medical Physics, Paris, France
2
I NSTITUT C URIE, Medical Physics, Saint Cloud, France
Purpose: To verify two dose delivery verification methods applied to helicaltomotherapy software using test-geometries of 3 levels of complexity.
Materials: Tomotherapy has developed a dose verification system which allows in-vivo daily dosimetry quality control in several points of the patient volume. Two dose delivery verification methods are available. First, the "Threshold" method uses the pulse by pulse signal collected by the on-board MVCT
exit detector during the radiation delivery to determine each MLC leaf open
time. With this information, and the machine output collected by the headmonitor chamber, a delivery sinogram can be generated and the dose computed. The second one, or "Database" method, also provides a delivery sinogram. However, this method uses attenuation data stored as a function of thebeam radiological path-length.For both methods, it is possible to reconstruct
the dose either using the planning KVCT or the daily MVCT image set.Threetest levels of increasing complexity were created. The first level consists of acylindrical PTV in a homogeneous cylindrical phantom (TomoPhantom, Gammex Middleton), for the three field widths available: 1, 2.5 and 5cm. The second level adds heterogeneities. PTV is simple but geometry constraints areapplied during the planning process (OAR, blocks ...). Finally, the third level
requires a head-and-neck Rando phantom planned using the head & neckclinical protocol implemented at our Institution for routine Tomotherapy IMRT
patient treatments.For the first two tests, absolute dose measurements were
performed using an ionization chamber (Exradin A1SL, Std. Imaging) andthen compared to the reconstructed dose in selected points within the volume. For level 3, relative dose measurements using Kodak EDR2 films werecompared to calculations. For all three geometries, calculation points wereselected to validate reconstructed dose in both low dose gradients (inside thePTV) and high dose gradients (penumbra) areas.
Results: Differences between measured and reconstructed dose were foundto be within 5% and 3.5mm in areas of low or high dose gradient respectively.
Both methods show good agreement with film relative dose distributions forthe head and neck configuration
Conclusions: The two methods have been validated for all three levels ofcomplexity. This study allowed us to determine some limitations of the TomoTherapy TPS by comparing calculated to measured dose especially in thecase of individual doses when the PTV is close to the phantom surface (between 1.5 and 3cm depth). Patient exit detector data is being currently collected during selected treatments to fully validate the system before clinicalimplementation.Conflict of Interest: Supported in part by a research agreement with TomoTherapy,S 174

P OSTERW EDNESDAY, M AY 11, 2011

Young scientists ESTRO Poster Session: MonteCarlo433 poster
MONTE CARLO DERIVED MONITOR BACKSCATTER AND OUTPUT
FACTORS USING DIRECTIONAL BREMSSTRAHLUNG SPLITTING
R. Ottosson1 2 , A. R. Beierholm1 , C. E. Andersen1 , C. F. Behrens2 , I. A.
Popescu3
1
R ISØ N ATIONAL L ABORATORY, T ECHNICAL U NIVERSITY OF D ENMARK,
Roskilde, Denmark2
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Oncology,
Herlev, Denmark
3
B.C. C ANCER AGENCY - VANCOUVER C ENTRE, Vancouver, BC, Canada
Purpose: Monte Carlo (MC) simulations report dose per incident particle on
the linac target. In order to convert to absolute dose; normalization to a reference dose is necessary. By doing so, the field-size dependent backscatterfrom the collimators to the monitor chamber needs to be considered. It has
previously been shown that by applying a two-step simulation protocol monitor chamber backscatter correction factors (BSF) can be simulated with MC. A
recently introduced variance reduction technique, Directional Bremsstrahlung
Splitting (DBS), has been reported to yield a 20-fold increase in photon fluence efficiency, for a 6 MV 10 0 beam, compared to uniform bremsstrahlung
splitting. The purpose of this study was to investigate whether DBS is compatible with the two-step protocol.
Materials: EGSnrc/BEAMnrc was used to MC simulate a Varian 2300iX
with and without the use of DBS. The treatment head was divided into twosegments: the static upper part (target through mirror) and lower field size
dependent part (monitor chamber through exit window), where the lower
part simulation used the phase space generated from the simulation of theupper part as input. Dose contribution to the monitor chamber was scoredfor both the upper and lower simulations (Dforw ch and Dback ch, respectively).
BSF were calculated according to eq (1). Target current measurements wereused as a reference. Subsequently, the lower phase space file was used as
input for a simulation in a homogeneous water phantom using DOSXYZnrc.
Relative Output Factors (ROF) were calculated through eq (2) and compared
to corresponding ion chamber (IC) measurements. The numbers of histories
were chosen so that the relative standard deviations (1 SD) of the ROFs
were approximately 1%.

BSF (Y × X) =ROF (Y × X) =

f orw
back
+ Dch
(10 × 10)Dchf orw
back (Y × X)
Dch
+ Dch

Dxyz (Y × X)
BSF (Y × X)
Dxyz (10 × 10)

(1)

(2)

Results: The BSFs and ROFs agreed, between MC simulations with andwithout DBS, within the uncertainties for all fields (figure 1). No significant
difference was found between measured and simulated ROFs, regardless of
the usage of DBS. The maximum deviation from IC measured ROFs were0.7% and 0.6% for simulations with and without DBS, respectively.

W EDNESDAY, M AY 11, 2011

P OSTERS 175

Conclusions: No significant difference was found between simulations withand without DBS and the results agreed with measurements. Thus, the results support that the DBS is compatible with the two-step simulation protocol.
However, DBS parameters need to be carefully selected. It is of particular importance to ensure that the splitting field radius is large enough to cover theintended field size and penumbrae region.
434 poster
MONTE CARLO MODELING OF THE SCANNING BEAM DIGITAL
X-RAY SOURCE (SBDX)
M. Bazalova1 , M. Weil2 , E. Graves3
1
S TANFORD U NIVERSITY S CHOOL OF M EDICINE, Department of Radiation
Oncology, Stanford, USA
2
S IRIUS M EDICINE, Golden, CO, USA
3
S TANFORD C ANCER C ENTER, Department of Radiation Oncology,
Stanford, USA
Purpose: To develop a Monte Carlo model of the scanning beam x-ray
source (SBDX) used for inverse geometry fluoroscopy imaging.
Materials: The SBDX (Triple Ring, Newark, CA) source was modeled in
the EGSnrc/BEAMnrc and DOSXYZnrc codes. The source consists of alarge (255) cm2 tungsten target and a scanning electron beam (Fig 1 topleft). The electron beam dwells at 10000 positions and the generated x-ray
beam is then collimated using a brass/lead collimator with 10000 holes. The
collimator circular holes are divergent and were modeled using the BLOCK
component module (CM). The 1 mm diameter circular openings wereapproximated with 8-sided polygons and the collimator hole divergence wasapproximated by 5 layers of BLOCK CMs. Each electron beam dwell position
had to be modeled separately. Bremsstrahlung cross-section enhancement
and uniform Bremsstrahlung splitting were used. Due to the complex andmemory intensive collimator geometry, only 121 collimator holes adjacentto the collimator hole of interest were simulated for each electron beam
position. The source was modeled for 80, 100, and 120 kV and validated
against EBT Gafchromic film measurements. Three EBT Gafchromic films
were sandwiched between four slabs of solid water. Two-dimensional (2D)
dose distributions were measured at 1, 6, and 11 cm depths with 16.5 cm
source-to-surface distance. The irradiation time was such that the central
axis dose was 2 Gy for each tube voltage. The measured (166) cm2 beamdose distributions were compared to MC simulations.
Results: Modeling only a section of the collimator sped up the simulation
by a factor of 30. The difference between the full collimator geometry andmodeling only a section of the collimator was within 1%. The MC and film
dose distributions were compared in terms of 2D dose distributions (Fig 1
top right), central axis depth dose curves (Fig 1 bottom) and beam profiles.
The measured 2D dose distributions showed a higher beam intensity
in the bottom left section of the beam which might be due to alignment
and/or beam-shape effects. The three measured central axis depth dosepoints agreed with MC simulations to within 5%. Similarly, the in-plane andcross-plane film beam profiles matched the MC ones to within 5% except forthe parts where the intensity of the measured beam was higher. These local
differences were up to 15%. The conversion factor from MC simulations to
the actual dose was found to be 4.43x1020 Gy/(200 mA,15 min)/(incident
particle).

Conclusions: A Monte Carlo of the inverse geometry scanning beam x-ray
source has been built and validated. The model can be further used for evaluation of patient imaging dose and for optimization of the source design.
435 poster
MONTE CARLO SIMULATION AND TG-43 PARAMETERS FOR THE
125I NUCLETRON SELECTSEED BRACHYTHERAPY SOURCE
X. J. Juan-Senabre1 , I. Porras2 , A. M. Lallena2
1
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofMedical Physics and Radiation Safety, Castelló de la Plana, Spain
2
U NIVERSIDAD DE G RANADA, Atomic, Molecular and Nuclear Physcis,
Granada, Spain
Purpose: To simulate the 125 I brachytherapy source SelectSeed using theMonte Carlo (MC) code PENELOPE [1]. In particular, we want the parameters of the formalism proposed by the AAPM TG-43 [2]. New parameterizations for the simulation data, for which precise fits can be achieved, areproposed
Materials: MC simulations were performed using PENELOPE code. The
tracking parameters used were: C1 = C2 = 0.05, Wcc = 10 keV, Wcr = 1
keV. The absorption energy for photons was chosen as 1 keV and 10 keV forelectrons and positrons. The TG-43 parameters {dose rate constant Λ, radialdose function g(r), anisotropy function F(r,θ ) and anisotropy factor Φan(r)}were reported and compared to those published by Karaiskos et al. [3]. The
geometrical and material source description was taken from [2], and the energy spectrum of the photons from TG-43 [2]. The number of particles employed in the simulations, depending on the particular quantity obtained, lie
between 109 and 1011 in order to guarantee enough statistics.
Results: For the Λ, the simulation result was 0.953 ± 0.004 cGy h-1 U-1 ,to be compared to the value found by Karaiskos et al. [3]: 0.954 ± 0.005
cGy h-1 U-1 . For g(r) the agreement is also good, within 2%. In addition, thefunction g(r) = (a0 + a1r)e- µ 1r (1 - (b0 + b1r+ b2r2 ) e- µ 2r ), provides accuratefits of data. This function consists of two factors. One of them expresses thelong range decay, being approximately constant for small r, and the other one
describes the build-up phase, being approximately constant beyond a valueof r near the maximum of g(r).The results for F(r,θ ) are in good agreement to
the reference study as well (see fig.). The new fit formalism proposed is thefollowing: the angular dependence of the dose rate is given by the product ofG(r,θ ) and F(r,θ ), which can be expanded exactly in the complete orthonormal
Legendre polynomials set of cos θ : F(r,θ ) = 1 - (a + b θ ) cos θ ecr Resultsfor Φan(r) are in good agreement to those found in [3] (see fig.). The values
obtained can be fitted using a function similar to that we used for g(r). The
description and fitting of the anisotropy factor near the source was studied
carefully and a new data table was reported.

Conclusions: In this work a detailed MC study of the dosimetry of the selectSeed brachytherapy source of 125 I was performed using the PENELOPE
code. The analysis of the different TG-43 parameters confirmed previous results found in the literature. The fact that our calculations were carried out
with a high statistics, allowed us to refine the values of some parameters previously reported. This was the case of the anisotropy factor near the source.
New precise functional fits with simple expressions have been found. We
consider that the new set of parameters can be easily implemented in therapy planning systems. References[1] Salvat F, Fernez-Varea JM, Sempau
J. PENELOPE, A Code System for Monte Carlo Simulation of Electron andPhoton Transport. Nuclear Energy Agency Organisation for Economic CoOperation and Development. Workshop Proceedings Issy-les-Moulineaux,France (2003). [2] Rivard MJ, Coursey BM, DeWerd LA, et al. Update of
AAPM Task Group N. 43 Report: A revised protocol for brachytherapy dose
calculations. Med. Phys. 31: 633-674 (2004). [3] Karaiskos P,Papagiannis
P and Sakelliou. Monte Carlo dosimetry of the selectSeed 125I interstitialbrachytherapy seed. Med. Phys. 28 (8): 1753-1760 (2001)

S 176

P OSTER436 poster
DEVELOPMENT AND EXPERIMENTAL VALIDATION OF TPSSOFTWARE TO DETERMINE THE DOSE OUTSIDE THE RADIATION
BEAM
B. Igor1
1

CEA LIST, Saclay, France

Purpose: Even if the IMRT modality allows a more accurate definition of
the target volume in radiotherapy, low doses are still delivered around the tumour to organs at risk. Epidemiological studies demonstrated the relationshipbetween peripheral doses and second cancers or heart diseases. Our aim
is to develop a Monte Carlo tool to compute the dose at the target volume
and the organs at risk in order to enable a decrease of the peripheral doseby adapting the treatment’s parameters. This tool will be implemented in a
TPS (Treatment Planning System). In this paper we expose the first validation step of the out-of-field Monte Carlo calculations, using a comparison withmeasurements in a specific water tank.
Materials: The PENELOPE MC (Monte Carlo) code has been parallelized
to save computation time by running the calculations on a cluster of 84 processors.To validate the simulations results, OSL (Optically Stimulated Luminescence) dosimeters made of Al2O3:C were used. The OSL Nanodots are
manufactured by LCIE Landauer. The OSL measurements are comparedwith NE2571 IC (ionization chamber) measurements. Irradiation has been
done at LNHB (French Primary Standard Laboratory) on a GE Saturne 43
accelerator at the 6, 12 and 20 MV qualities. The only difference with theirradiation conditions proposed in the AIEA protocol 398 is the use of a large
water phantom specially machined for this experiment; it is a 60x30x30 cm3tank.
Results: Three main corrections are done on the OSL measurements: particular sensitivity for each Nanodot, air calibration factor Dwater/Kair and energy
dependence correction. The picture shows out-of-field dose profiles at reference depth (10 cm) for MC calculations, ionization chamber and OSL measurements. The doses are normalized to the maximum of dose. In this figure,the energy dependence is not corrected for the OSL. Considering that theionization chamber dose is the reference value, one can observe that OSLs
always over-estimate the dose. The energy response of the OSL dosimeterhas been investigated to correct this over response.

W EDNESDAY, M AY 11, 2011
Purpose: The purpose of this work is to investigate the capability of the
FLUKA Monte Carlo (MC) code to reproduce the predictions of the Elekta
Leksell Gamma Knife Perfexion (LGK-PFX) treatment planning software Leksell GammaPlan (LGP) for an homogeneous target. This is the first step tobuild a MC verification of treatment planning in actual clinical cases.
Materials: The LGK-PFX is a 60 Co medical device based, manufactured by
Elekta AB Sweden, able to apply a sophisticated radiation surgery technique
for the treatment of different brain pathologies. By means of three different
collimator sets (4, 8 and 16 mm) gamma rays are focused on the isocenterof the field. LGP is the treatment planning software specifically designed for
LGK-PFX. Since LGP employs a simplified physical model, the quality assurance program requires to verify its the output by means of external methodologies. The intrinsic difficulties of dose measurements, especially in small
beams field, makes the Monte Carlo (MC) method a suitable and powerfultool in order to perform an accurate dosimetric comparison in critical regions.
FLUKA is a multipurpose MC code which finds many different applications inphysics, developed as a joint project of INFN and CERN. It computes transport and interaction of particles over a wide energy range. Thanks to thecollaboration with Elekta, which provided us with the technical construction
details of the Perfexion radiation unit under a confidential agreement, we
could build an accurate input model for our FLUKA simulation. In order tovalidate the MC results, we have compared to LGP results the relative linear
dose distributions along the three coordinated axes for each kind of collimatorsize and the output-factor (OF) for various size of scoring volumes. A satisfactory agreement has been achieved between FLUKA calculations and the
LGP predictions.
Results: FLUKA MC calculation provided the OF values of 0.921 and 0.792
for the 8mm and the 4mm collimators. These values are in good agreementwith the Elekta provided data which are 0.924 and 0.805 respectively. Asa first example of the good agreement achieved in the relative linear dose
profile comparison, the 16mm collimator profile along the coordinated x-axis
is shown in figure.

W EDNESDAY, M AY 11, 2011clinical electron beams in order to accurately calculate electron beam dose
distributions in homogeneous and heterogeneous media. In addition to this,electron output factors can be quickly calculated, eliminating the need of an
output measurement.
Materials: Twenty breast cancer patients who received adjuvant whole breast
RT followed by an electron boost to the tumor bed were selected for thisstudy. Patient treatment plans from Eclipse TPS were imported into MMCTP
for a MC calculation of electron output factors, PDDs and 3D-dose distributions. MMCTP facilitates complex electron beam treatment planning using BEAMnrc and DOSXZYnrc MC codes for the calculation of output factors from various electron beam energies and applicator sizes. Measured
PDDs and dose profiles at various depths of clinical interest and for multiple
cutout sizes were used to commission the MC electron beam model. Electron
beam commissioning also included 2D-measurements performed with EBT-2
GAFCHROMICTM film in homogeneous and heterogeneous cases.
Results: Electron output factors for those fields were compared against measurements and were accurate to within 3.0%. A dose difference of 3% anddistance-to-agreement of 3 mm were used to compared two dimensionaldose maps using the gamma method, and results are very promising. The
average electron MC calculation time was 2 hours.
Conclusions: Our accurate electron beam model incorporated into our MCTPS is a valuable treatment planning tool for electron beams. Clinical electron treatment plans can be quickly recalculated within MMCTP for patient
specific quality assurance (QA) verification. A clinical implantation will also
provide the clinic with an automated alternative to the electron cutout output
measurements.

P OSTER

S 177

profiles at two depths) GGPB shows significant dose underestimation (max.
~20 %) in lung and overestimation in water adjacent to lung (max. ~20 %),whereas eMC results in much better agreement with MC dose distributions,
showing an overestimation of 5 % at maximum.

Conclusions: We conclude that eMC introduces definite improvements into
clinical electron beam dose calculation, especially in aforementioned geometries, when compared to GGPB. On the other hand, MC methods prove theirusability as an accurate dose determination method for QA purposes. Anyhow, one has to bear in mind that since the dose differences in target volumes
and/or OARs between the two algorithms may be relatively large, special attention has to be drawn, when using eMC after commissioning and assessing
if a plan meets given dose prescription and/or DVH constraints. Criteria usedwith GGPB may have to be revised/modified to account for the increased
dose calculation accuracy of eMC. E.g., with GGPB, in a chest wall irradiation
with one anterior field the dose in lung would be underestimated, the dose inlung/mediastinum boundary and in coronaries would be correctly calculated
and the dose in myocardium would be overestimated.

Young scientists ESTRO Poster Session: Functional imaging
440 poster

439 poster

Conclusions: The results obtained in this work show that our full FLUKA
simulation is able to reproduce the LGP prediction in homogeneous media.
We can now proceed to work at the comparison of MC results with LGP predictions in the case of heterogeneous targets.

MC-BASED VERIFICATION OF ABSORBED DOSE DISTRIBUTIONSIN THE LUNG CALCULATED BY TWO ELECTRON BEAM ALGORITHMS
J. Ojala12 , S. Hyödynmaa12
1

TAMPERE U NIVERSITY H OSPITAL, Department of Oncology (Radiation
Therapy), Tampere, Finland
TAMPERE U NIVERSITY OF T ECHNOLOGY (TUT), Department of Biomedical
Engineering, Tampere, Finland2

438 poster
The MC data are in good agreement with the IC measurements up to 200 mm
from the centre of the beam. For further positions, the calculations underestimate the dose in comparison with the IC measurements. In the beam, thedata are in good agreement (error < 3 %).
Conclusions: After correcting the energy dependence, the OSL dosimeter
will give satisfying results so that it can be used to validate the calculationsof the new MC calculation tool in a real IMRT configuration with an anthropomorphic phantom. Further research is necessary to explain the discrepancy
between measured and calculated dose for large distances. Besides, theimplementation of reduction variance techniques in the MC tool should be
helpful by allowing a better accuracy of the calculation out of the beam. Partof the work has been done within the frame work of EURADOS WG9.
437 poster
FLUKA MONTE CARLO SIMULATION FOR THE LEKSELL GAMMAKNIFE PERFEXION: HOMOGENEOUS MEDIA.
G. Battistoni1 , N. Bertolino2 , M. G. Brambilla2 , F. Cappucci1 2 , H. S.
Mainardi2 , A. Torresin2
1
I STITUTO N AZIONALE DI F ISICA N UCLEARE (INFN), Milano, Italy
2
A ZIENDA O SPEDALIERA O SPEDALE N IGUARDA C A ’G RANDA, Milan, Italy

MONTE CARLO BASED ELECTRON BEAM TREATMENT PLANNING
FOR BREAST CANCER
E. Mitrou1 2 , A. Alexander2 , F. DeBlois1 2 , J. Thebaut1 2
1
SMBD J EWISH G ENERAL H OSPITAL, Radiation Oncology Physics,
Montréal, Canada
2
M C G ILL U NIVERSITY H EALTH C ENTER, Medical Physics Unit, Montreal,
CanadaPurpose: Breast cancer is the third most common type of cancer in Canada
with nearly 23 300 new cases per year. Current treatment options include a
combination of surgery, chemotherapy, hormonal therapy and radiation therapy (RT). For early stage invasive breast cancer, a breast-conserving treatment involving RT is usually the preferred treatment. It involves tangential
photon fields to the whole breast followed by an electron boost field to the tumor bed. Electron RT, under a specific suitable geometry may offer a numberof advantages over photon RT. The high surface dose, combined with a rapid
dose fall-off beyond the target volume may increase the tumor control probability and may decrease the normal tissue complication (lung, heart). Deterministic algorithms for electron dose calculations that are found in commercial planning systems often yield treatment planning inaccuracies. Therefore
electron treatments are mostly clinically planned without dose distributions.
Our current research aims to use Monte Carlo (MC) methods, incorporated
within the McGill Monte Carlo Treatment Planning (MMCTP) system, to model

Purpose: In this work the purpose was to verify electron dose distributions
calculated in both simple homogeneous water phantom and more complex
phantoms with lung inhomogeneities by two electron beam dose calculation
algorithms in Eclipse™8.6 TPS by Varian Medical Systems (Palo Alto, California, USA). The resulting dose distributions of the algorithms, Generalized
Gaussian pencil beam (GGPB) algorithm and electron Monte Carlo (eMC)
algorithm, were compared to MC calculations and measurements.
Materials: General purpose MC codes BEAMnrc/DOSXYZnrc were used to
calculate dose distributions in similar phantoms as with GGPB and eMC, forwhich treatment plans were prepared using Eclipse™, simulating radiotherapy of volumes representing water phantom, water phantom with lung slab
and a water phantom with half lung slab representing a simplified version ofan anterior chest wall irradiation (See Fig.). The MC model was based on
Varian Clinac 2100C/D linear accelerator and it was optimized for 16 MeV
electron beam to produce dose distributions of high accuracy compared tomeasurements. MC dose distributions and measurement data were thenused for verification of the algorithms.
Results: In homogeneous phantom eMC and GGPB show very good agreement with MC and PTW 34001 IC measurements, which were verified witha combination of Gafchromic EBT radiochromic film, Scanditronix DEB050
stereotactic diode and PTW 60003 diamond detector measurements. E.g.,
gamma values, using acceptance criteria of 1 % / 1 mm, for each PDD calculation at CAX compared to measurement were 0.26, 1.27 and 1.63 forMC, eMC and GGPB, respectively. In heterogeneous phantoms differences
are more pronounced. Especially in phantom with half lung slab (See Fig.

A GRADIENT-BASED SEGMENTATION METHOD FOR FDG-PETBASED GTV DELINEATION: CLINICAL VALIDATION IN NSCLC
M. Wanet1 , J. A. Lee1 , B. Weynand2 , M. De Bast1 , A. Poncelet3 , V.
Lacroix3 , E. Coche4 , V. Grégoire1 , X. Geets5
1
UCL C LINIQUES U NIV. S T.L UC, Center for Molecular Imaging andExperimental Radiotherapy , Brussels, Belgium
2
UCL C LINIQUES U NIV. S T.L UC, Department of Pathology, Brussels,
Belgium
3
UCL C LINIQUES U NIV. S T.L UC, Department of Thoracic Surgery, Brussels,
Belgium
4
UCL C LINIQUES U NIV. S T.L UC, Department of Radiology, Brussels,
Belgium
5
UCL C LINIQUES U NIV. S T.L UC, Department of Radiation Oncology,
Brussels, Belgium
Purpose: The integration of PET in the treatment planning is promising but
remains technically complex especially for the accurate definition of the tumor boundaries in regard of many available tools. We developed an innovative PET segmentation method that exploits the image gradient information
and was previously validated on phantoms and head and neck patients withpathological specimens. In this context, we aimed to validate this gradientbased segmentation method for GTV delineation on FDG-PET in NSCLC
patients through surgical specimen, in comparison with threshold-based approaches and CT.
Materials: Briefly, the concept of the gradient-based method relies on the association of the boundaries of an object of interest with the gradient-intensity
crests observed in the image. The acquired images are denoised and deblurred and these preprocessing steps sharpen the image gradient, making
it easier to detect peaks of gradient magnitude with algorithms, such as thewatershed transform. In this study, the validation of the method in NSCLC
patients was performed using the surgical specimen as "ground truth" reconstructed in 3D. We compared the macroscopic primary tumor volume with
GTVs obtained using contrast-enhanced CT and gated FDG-PET. For the delineation of the different GTVs, we used the gradient based method as well as
the conventional threshold-based segmentation approaches (i.e. the source
to background ratio method and fixed threshold values at 40% and 50%) on
PET images reconstructed with voxel sizes of 2 and 4 mm and two window
settings (i.e. lung and mediastinal windows) on CT images.

S 178P OSTER

Results: FDG-PET provided volumes close to the surgical specimen whileboth lung and mediastinal windowed CT led to a large overestimation of themacroscopy especially for cases of poor defined tumor (atelectasia or lungfibrosis). In contrast, the mediastinal windowed CT accurately assessed themacroscopic specimen when tumors were well defined. Among various PET
segmentation methods, estimation of the true tumor volume was the best
through gradient-based technique. Furthermore, PET images with a low resolution (i.e. 4 mm voxels) resulted in larger GTVs on average, independentlyof the segmentation method used.
Conclusions: FDG-PET improved the GTV definition in NSCLC comparedto CT particularly when the primary tumor was surrounded by modificationsof the lung parenchyma. In this context, the gradient-based method outperformed the threshold-based ones in terms of accuracy and robustness aspreviously observed on phantoms and head and neck patients. Therefore,
we believe that the gradient-based method should be used as the reference
segmentation in the field of PET-driven delineation of head and neck and lungtumors.
441 poster
FLT PET IMAGING FOR WEEKLY EVALUATION OF BONE MARROWRESPONSE TO CHEMORADIATION THERAPY IN CERVICALCANCER PATIENTS
S. McGuire1 , G. Jacobson1 , Y. Menda2 , L. Ponto2 , B. Gross1 , J. Bayouth1
1
U NIVERSITY OF I OWA H OSPITALS AND C LINICS, Radiation Oncology, Iowa
City, USA2U NIVERSITY OF I OWA H OSPITALS AND C LINICS, Radiology, Iowa City, USA
Purpose: The purpose of this study was to evaluate the dose response ofbone marrow (BM) using FLT PET imaging at multiple time points duringchemoradiation therapy.
Materials: Two cervical cancer patients were enrolled in an IRB approved
protocol to obtain FLT PET images prior to and during chemoradiation therapy. The pre-therapy image was used as a control for bone marrow FLT
uptake change and to create a bone marrow sparing IMRT plan. Initially, an
IMRT plan was created to meet target and normal tissue standards specified in RTOG 0418. Then, bone marrow volumes identified using FLT PET
SUVs were added to the optimization to spare bone marrow without significantly changing normal tissue or target DVHs. Each subject was imaged
1 week (after 5 fractions), 2 weeks (after 10 fractions), and 3 weeks (after
15 fractions) post therapy of 1.8 Gy/fraction to the PTV and 1 cycle of 70
mg cisplatin chemotherapy/week. Weekly CBCs were monitored throughout
chemoradiation therapy to correlate with change in FLT uptake in bone marrow. The bone marrow dose response was measured by FLT PET mean SUV
within 1 Gy/week dose volumes within the boney pelvis, lower vertebrae, andfemurs.
Results: Example axial images from the FLT PET week 0, 1, 2, and 3 scansof subject 1 with the total isodose distribution overlay are shown in Figure 1.
FLT uptake is visibly diminished after week 1 within the 15 Gy isodose level (3Gy/week). After week 2, the FLT uptake in the bone marrow is indistinguishable from background. Mean BM SUV decreased 50% in the 4-5 Gy volume
and a ~70% maximum decrease occurred at 7 Gy or higher after 1 weekof therapy for both subjects. Mean BM SUV also decreased ~50% or morein the 4-6 Gy volume after 2 weeks of chemoradiation therapy, and a ~80%
maximum decrease occurred at ~14Gy for both patients. Both the mean SUV
decrease of 50% and maximum decrease occurred at higher dose levels after 3 weeks for subject 1. A 50% decrease was not exceeded until the 6-9
Gy volume. However, a 50% decrease for subject 2 was exceeded in the 3-6
Gy volume after 3 weeks. A ~83% maximum decrease occurred at ~24 Gy
for both subjects. The systemic effect of bone marrow activity change during
therapy was observed in WBC changes for both subjects. Subject 1 WBCs
were 5.3, 4.4, 4.0, and 2.4 K/mm3 for weeks 0, 1, 2, and 3 respectively. Subject 2 WBCs were 12.2, 8.8, 7.3, and 4.6 K/mm3 for weeks 0, 1, 2, and 3
respectively.

W EDNESDAY, M AY 11, 2011
Conclusions: In two subjects, 5 Gy decreased FLT uptake 50% or more asmeasured by mean SUV in the bone marrow of the pelvic region. This decrease appeared to be independent of time within the first 2 weeks for one
subject and within 3 weeks for the other. It may be that bone marrow radiation dose response is independent of time and fractionation schemes usually
implemented for normal tissue sparing. FLT PET was useful in identifying active bone marrow in the pelvis and demonstrating spatial bone marrow toxicity
early in chemoradiation therapy.
442 poster
DYNAMIC FDG-PET IMAGING FOR TREATMENT MONITORING IN
RADIOTHERAPY OF CANINE HEAD AND NECK TUMORS
A. Soevik1 2 , J. Rødal2 3 , H. Kippenes Skogmo1 , E. Malinen2
1
N ORWEGIAN S CHOOL OF V ETERINARY S CIENCE, Department of Companion Animal Clinical Sciences, Oslo, Norway
2
N ORWEGIAN R ADIUM H OSPITAL, Department of Medical Physics,
Montebello, Norway
3
N ORWEGIAN U NIVERSITY OF S CIENCE AND T ECHNOLOGY, Department of
Physics, Trondheim, Norway

W EDNESDAY, M AY 11, 2011
ing two imaging protocols one low dose ("Clinical") and large slice thickness(80kV, 100mA, 2.5 mm) and one with higher dose ("QA") and smaller slice
thickness (80kV, 300mA, 1.25 mm). Both were imaged for 90 seconds witha 1 s gantry rotation. Two scanners were investigated in this work a GE Discovery ST 16 slice scanner and a Toshiba Aquilion One 320 slice scanner.
Results: This phantom and its surrounding flow system are capable of creating a wide range of clinically relevant TACs which are reproducible with minimal error between experiments (σ /µ <1.2%, n=3). The TACs generated by
the system are predictable based on the system parameters to a high degreeof accuracy (R2 > 0.95). The effect of ROI size on the arterial input function(AIF) was investigated to determine an operating range of ROI sizes whichwere minimally affected by noise at the low end and partial volume effects
at the high end. It was possible to establish the measurement sensitivity ofboth the Toshiba (ROI radius from 1.0 to 2.8 mm "Clinical", 1.0 to 3.0 mm"QA") and GE scanner (1.0 to 2.6 mm "Clinical", 0.8 to 3.0 mm "QA"). (Figure 1 depicts Toshiba 320 "Clinical" protocol). This QA protocol also provides
the ability to evaluate the effect of the AIF error on kinetic model parameter
predictions which will be discussed subsequently.

Purpose: To investigate the potential role of dynamic FDG-PET imaging intreatment monitoring and early response assessment in fractionated radiotherapy of canine head and neck tumors.
Materials: Three dogs with spontaneous head and neck tumors received
intensity-modulated radiotherapy (IMRT) with 42 47 Gy given in 10 fractions.
Dynamic FDG-PET imaging was performed 4 5 days prior to the start ofradiotherapy, at mid-treatment (after 16.8 18.8 Gy), and at 3 12 weeks after the completion of treatment. Dynamic contrast-enhanced CT (DCECT)
was also performed at the pretherapy session. From the dynamic PET images, the kinetic rate parameters K1 k3, the vascular fraction (VB), andthe metabolic rate of glucose (MRglc), were obtained through the applicationof a three-compartment pharmacokinetic model. Furthermore, time-activity
curves (TACs) were evaluated, and the standardized uptake value (SUV) 45
minutes post injection was calculated.
Results: For all three patients, MRglc and SUVdecreased and k2 increased
from the pre- to the intertherapy PET session, while response patterns varied
between patients for the remaining parameters. However, parametric mapsof most of the pharmacokinetic parameters showed increased heterogeneityfrom the pre- to the intertherapy PET session. There was in general good
agreement between the DCECT uptake curves and the initial phase of the
PET TACs. Furthermore, the changes observed in the TACs from pre- tointertherapy PET sessions were most pronounced at the end of the uptake
curves, indicating that the metabolic changes predominated over the vascularchanges in response to treatment. In patients where tumor regrowth was
detected on the post-treatment PET examination, both MRglc and SUV wereincreased on the post-treatment PET scan compared to the inter-treatment
values.
Conclusions: Kinetic analysis of dynamic FDG-PET images may prove useful for monitoring the effect of radiotherapy. Furthermore, the changes in FDG
uptake kinetics may provide information on changes in tumor biology during
and after treatment and may help elucidate how these relate to treatment
response.

S 179

dynamic imaging (DI) leads to characterization of functional properties oftumors and assessment of response to therapy. The first hybrid PET/MRI
systems have appeared on the market allowing concurrent DI.The aim of
this study was to explore the potential complementary value of concurrent
PET/MRI DI on the accuracy of PK analysis for both modalities. This aim ispursuit by a simulation of PK analysis exploiting the concept that the underlying patient morphology is the same during concurrent DI.
Materials: PET and MRI PK were analyzed using two compartmental models
in which the extracellular-extravascular-space (ve) and the blood-volume fraction (vp) represented the underlying morphology. We set-up a Monte-Carlosimulation in which 1) PET and MRI dynamic data from 1000 different sets ofmodel parameters were generated (ground-truth), 2) noise was added to thedata, 3) the parameters of the PET and MRI models were fitted to the data.
Three methods of exploiting the underlying morphology during optimization
were used in the fits: 1) ve and vp were equal in the MRI and PET models;2) ve and vp were fitted on MRI data and subsequently used to fit the PET
data; 3) independent fit of PET and MRI data.Acquisition times in the simulation were varied between 10 and 20 minutes for PET, and between 4 and 10
minutes for MR. For each parameter the ratio between the fitted parameterto ground truth was defined; the average of the ratio of every fit represented
the accuracy of the method; the variance of the ratios represented the precision. The parameters were: ve, the MRI perfusion constant Ktrans and thePET uptake constant k3. The overall precision of the fit was the sum of thevariances of the ratios; the overall accuracy was the average of ratios.
Results: Method 1 increases the overall accuracy of estimating k3 compared
to method 3: 0.94±0.1 against 0.78±0.08. The precision for ve was comparable (0.97±0.04 and 1.05±0.07, respectively), as well as the precision for
Ktrans (1.02±0.07 and 1.03±0.02, respectively). The average overall accuracy of the fits was comparable for the three methods; in terms of averageoverall precision, method 1 and 2 had comparable performance, superior tothat of method 3. The overall precision correlated with increasing PET acquisition time : R=-0.721 (method 1), R=-0.853 (method 2), R=-0.541 (method
3).
Conclusions: Concurrent methods in the PK analysis of PET/MRI data leads
to a higher accuracy and precision compared to separate PK analysis of PET
and MR data.
445 poster
INTENSITY PROFILE BASED MEASUREMENT OF PROSTATE GOLD
MARKER IMPACT ON 1.5T AND 3.0T DIFFUSION-WEIGHTED MR
IMAGES
S. Rylander1 , S. Thörnqvist12 , S. Haack3 , E. Morre Pedersen4 , L. P.
Muren12A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
3
A ARHUS U NIVERSITY H OSPITAL, Department of Clinical Engineering,
Aarhus C, Denmark
4
A ARHUS U NIVERSITY H OSPITAL, Department of Radiology, Aarhus C,
Denmark
1

443 poster
QUANTITATIVE DCE-CT IMAGING QUALITY ASSURANCE WITH ANOVEL DYNAMIC FLOW PHANTOM
B. Driscoll1 , H. Keller1 2 , C. Coolens1 2
1
P RINCESS M ARGARET H OSPITAL, Department of Radiation Physics,
Toronto, Canada
2
U NIVERSITY OF TORONTO, Department of Radiation Oncology, Toronto,
CanadaPurpose: To produce typical clinical time-attenuation curves (TACs) using anovel dynamic flow imaging phantom with the goal of developing a Quality
Assurance protocol for DCE-CT measurement sensitivity analysis allowing
the quantification and validation of DCE-CT measurements under realistic
flow conditions.
Materials: The phantom is based on a simple two-compartment model and ismade up of an external cylinder with an internal section containing openings
to exchange mass between the compartments. The phantom was printed
using a 3D printer and is made of the water-neutral polymer PC-ABS. Initial characterization of the phantom involved simple flow measurements andprogressed to DCE-CT experiments in order to test the phantoms range andreproducibility. The phantom was then utilized to generate realistic input TACs
in which the arterial input function has both an original bolus and secondary
recirculation peak. A predictive compartmental model was generated which
can accurately predict the TACs generated by the phantom given a set of control parameters (flow rate, contrast injection pulse and output flow valve positions). A DCE-CT quality assurance protocol was developed and performed
using the phantom to investigate image noise, partial volume effects and CT
number accuracy under realistic flow conditions. Scans were performed us-

P OSTER

Figure 1: Measurement Sensitivity Analysis of DCE-CT
Conclusions: The dynamic flow imaging phantom is capable of producing
accurate and reproducible results which can be predicted and quantified resulting in a unique tool for DCE-CT quality assurance under realistic flow conditions which can be applied to compare different CT scanners and imaging
protocols.
444 poster
CONCURRENT ANALYSIS OF DYNAMIC PET AND MRI INCREASESPRECISION OF PHARMACOKINETIC ANALYSIS
E. Pasca1 , J. J. Sonke1 , K. Gilhuijs2
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiotherapy Department, Amsterdam, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiology Department, Amsterdam, Netherlands
Purpose: PET and MRI are currently used for tumor characterization and fortarget delineation in radiotherapy; pharmacokinetic analysis (PK) of PET/MRI

Purpose: Diffusion-weighted imaging (DWI) has demonstrated promising results in visualizing prostate tumors either solely or accompanied with T2weighted imaging. However, the echo planar acquisition technique utilized
in DWI is prone to susceptibility artefacts. The purpose of this study was toinvestigate the impact of fiducial markers (FMs) on DW images (DWIs).
Materials: An Agar-gel phantom was constructed with two cylindrical goldFMs (1 x 3 mm) embedded. Transversal T1W (1.5T/3.0T; TE: 5/4 ms, TR:
500/400 ms, in-plane resolution: 1.09 x 1.09/1.88 x 1.88 mm/pxl) and DWIs
acquired at same slice position and similar FOV was accomplished with 1.5T
and 3.0T MRI scanners. The echo planar imaging based DW sequence parameters, based on clinical protocols of the pelvis, were: 1.5T/3.0T; b-value:
0, TE: 98/89 ms, TR: 3300/5016 ms, in-plane resolution: 2.19 x 2.19/2.02 x
2.02 mm/pxl, acquisition-matrix: 128 x 128/119 x 119, slice-thickness: 4 mm.
The CT images were registered with the T1W images. The intensity profile
across reconstructed FMs in x- and y direction was investigated to assess
relative position of FMs and size of intensity variations caused by FMs in the
DWIs and T1W images. The mean minimum intensity position (mMIP) of FMs
on the DWIs was compared to the T1W images.
Results: The FM artefacts were particularly pronounced in the phaseencoding (PE) direction where the mean size of the intensity variations developed from the FM reconstruction was: 1.5T/3.0T; DW: 2.48 ± 0.24/1.97± 0.35 cm, T1W: 0.47 ± 0.12/0.34 ± 0.11 cm. The estimated mMIPs of
FMs on T1W images matched the center-positions of markers on CT images.
The analyzed mMIPs on DWIs relative to the T1W images showed a mean
position displacement in opposite direction of the PE direction: (1.5T/3.0T;
1.9 ± 1.6 (max: 3.6)/8.1 ± 2.9 mm (max: 11.8)) and an insignificant shift infrequency-encoding (FE) direction (0.4 ± 0.5 mm). The measured distance
between mMIPs of the two FMs was: 1.5T/3.0T; DW: 4.08/4.20 cm, T1W:
4.10/4.06 cm and the relative distance between FMs in the CT images was
4.12 cm.
Conclusions: The resulting artefact from marker reconstruction on acquired
DWIs (1.5-3.0T) extended considerably in the PE- in comparison to the FE

S 180P OSTER

direction. This introduces an uncertainty in performing accurate image interpretation and use of FMs for image registration on DWIs in the PE direction.
The mMIPs of FMs on DWIs relative the reference position showed a displacement towards the direction opposite of the PE direction.
446 poster
REPRODUCIBILITY STUDY OF DIFFUSION-WEIGHTED IMAGING
IN RECTAL CANCER.
M. Intven1 , O. Reerink1 , M. Philippens1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands
Purpose: Diffusion-weighted MR imaging (DW-MRI) reflects the microanatomy in tissues and is increasingly used in rectal cancer for response
assessment in order to allow a more tailored minimal invasive approach forgood therapy responders. To fully implement DW-MRI in clinical practice themeasurements have to be reproducible. Therefore the purpose of this pilot
study was to examine the reproducibility of DW-MRI in rectal cancer at 1.5T.
Materials: Five patients receiving short course pre-operative radiotherapy(5x5 Gy) underwent daily 1.5T MRI scans before each treatment fraction. In
every MRI session of 25 minutes two diffusion weighted (DW) scans wereacquired, leading to 23 DW series for analysis. Both the repeatability during
a single session and the day-to-day changes were analyzed.On each MRI
scan with b-value 0 s/mm2 the rectal tumor was delineated for analysis. The
apparent diffusion coefficient (ADC) map was generated using DW-MRIs withb-values of 200 and 800 s/mm2 by a linear regression, ln(S) = ln(A)-b*ADC,
where S represents the signal intensity and A the relative amplitude. BlandAltman analysis was performed to estimate ADC variations within one scansession using the repeated DW-MRIs and for the day-to-day variation using
the first DW-MRI of the day, comparing day 1-2, 2-3, 3-4 and 4-5.
Results:
The mean ADC value for all measurements was
1.07x10-3 s/mm2 (SD 0.15x10-3 s/mm2 ).
For every individual patient,mean ADC values over all days were 1.08 (SD 0.05x10-3 s/mm2 ), 1.27 (SD
-3
2
-3
2
0.10x10 s/mm ), 1.07 (SD 0.05x10 s/mm ), 0.97 (SD 0.04x10-3 s/mm2 )and 0.82 (SD 0.07x10-3 s/mm2 ). Bland-Altman analysis for the reproducibility of ADC measurements during one scan time showed a bias of
0.02x10-3 s/mm2 and a coefficient of repeatability of 0.24x10-3 s/mm2 (figure1). The measured tumor ADC values were all within the 95% limits ofagreement except one. The bias for the grouped day-to-day analysis was-0.02x10-3 s/mm2 and the coefficient of repeatability 0.18x10-3 s/mm2 .

W EDNESDAY, M AY 11, 2011
Young scientists ESTRO Poster Session: Radiobiology and dose volume parameters
447 poster
RELATIONSHIP BETWEEN DOSE DISTRIBUTION ON THE RECTALWALL AND LATE TOXICITY AFTER PROSTATE RT WITH ENDORECTAL BALLOON
A. van der Geest1 , F. Buettner2 , S. Gulliford3 , M. Partridge2 , S. Webb3 , D.
P. Dearnaley4 , M. Sydes5 , J. Kaanders1 , R. J. Smeenk1 , E. van Lin1
1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Nijmegen, Netherlands
2
I NSTITUTE OF C ANCER R ESEARCH, Sutton, United Kingdom
3
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Sutton, United Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Sutton, United Kingdom
5
M EDICAL R ESEARCH C OUNCIL, London, United Kingdom
Purpose: To correlate spatial dose distribution parameters for the rectal wall,
based on dose-surface maps (DSMs), with late anorectal toxicity in patients irradiated for prostate cancer. To investigate the effect of an endorectal balloon(ERB) on both DSM and toxicity, two patient populations were compared: onetreated with an ERB and one treated without ERB. An attempt was made toformulate clinically applicable constraints and recommendations for reducing
late anorectal toxicity.
Materials: Two hundred-thirty-seven patients, irradiated for localised prostate
carcinoma were included: 87 treated with 3D-CRT or IMRT to a total dose of
70 Gy in 2.5 Gy fractions (biologically equivalent to 78 Gy in 2 Gy fractions)using an ERB (RUNMC group), and 150 irradiated with 3D-CRT to a total
dose of 74 Gy in 2 Gy fractions without ERB (MRC group). During follow up,
rectal bleeding, proctitis, sphincter control, stool frequency, sphincter control
management, loose stools and rectal urgency were scored. To depict rectal
wall dose distributions, DSMs were generated. The rectal wall was delineatedon the treatment planning CT, whereupon the rectal wall contour was virtually
cut open posteriorly to ’unfold’ the rectum. The dose delivered to the rectal
wall was projected onto it, thus creating a DSM. Subsequently, a cumulative
dose-surface histogram (DSH) was calculated as well as the following spatialdescriptors: centre of mass, longitudinal and lateral extent, and eccentricity of the dose distribution at each dose level. Correlations between dose
distribution shapes and anorectal toxicity were assessed. The differences indose distribution shapes and toxicity between the patient populations wereanalysed.
Results: Rectal bleeding after prostate RT was significantly correlated with
DSH, the lateral extent and longitudinal extent of the dose to the rectal wallat doses ranging from 32-65 Gy. The strongest predictor was a lateral extent
of 43% of the circumference of the rectum at 55 Gy. For the other toxicity parameters no significant correlations were observed. The RUNMC patient population, treated with a daily inserted ERB, has significantly less late anorectal
toxicity and a significantly lower lateral dose extent.
Conclusions: The lateral extent of the rectal wall dose was significantly correlated with rectal bleeding, especially at a dose level of 55 Gy. Consequently,
it is recommended that rectal doses of 55 Gy or higher are limited to 43% orless of the rectal circumference. Use of ERBs may facilitate this.
448 poster
CORRELATIONS BETWEEN 3D DOSE DISTRIBUTION TO THE
ANAL SURFACE AND LATE RECTAL TOXICITY AFTER PROSTATERADIOTHERAPY
F. Buettner1 , S. Gulliford1 , S. Webb1 , M. Sydes2 , D. P. Dearnaley3 , M.
Partridge1
1
T HE I NSTITUTE OF C ANCER R ESEARCH AND R OYAL M ARSDEN H OSPITALNHS F OUNDATION T RUST, Joint Department of Physics, London, United
Kingdom
2
MRC C LINICAL T RIALS U NIT, Cancer Group, London, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Academic Unit ofRadiotherapy, Sutton, United Kingdom

Conclusions: In this pilot study, we analyzed the reproducibility of DW-MRI in
rectal cancer at 1.5T. Our results show small variations in ADC values within
one scan session. These variations are probably caused by movement of
the rectal tumor during the scan duration due to peristalsis and air bubbles.
Day-to-day variations were also small but increased as the week advanced
possibly due to the radiotherapy treatment effect which causes microscopic
tumor changes and an increase in bowel movements. In conclusion, the coefficient of reproducibility for DW-MRI analysis in rectal cancer is acceptable(15-25% of the mean value). This is important to pave the way for clinicalimplementation of DW-MRI for tumor response assessment.

Purpose: Many studies have been performed to assess the dose-response of
the rectum with most focusing on late rectal bleeding. However, it has beenreported that other symptoms such as rectal urgency or lack of sphincter
control have a large impact on quality of life. It has been suggested thatdifferent symptoms are related to the dose to different parts of the anorectal
wall. The aim of this study is to quantify correlations between the 3D dose
distribution to the anal surface and clinical outcome.
Materials: The rectum was outlined from the anus taken at the level of theischial tuberosities or 1 cm below the planning target volume, whichever was
more inferior to the rectosigmoid junction, and the anal canal was definedas the caudal 3 cm of the rectum. Dose-surface-maps (DSMs) were generated by virtual unfolding of the anal canal. Binary DSMs were generated
by thresholding the primary maps at 29 doses between 15 Gy and 71 Gy.
At each dose level an ellipse was ?tted to the largest dose-cluster. Lateraland longitudinal extent were quanti?ed by projecting the axes of the ellipse
to the main axes of the DSMs. The irregularity was described by the ec-

W EDNESDAY, M AY 11, 2011
centricity of the ellipse. Correlations between these measures as well as
conventional DSHs, mean dose and maximum dose and 7 clinically relevant
endpoints were quanti?ed. This was done by maximally selecting standardised Wilcoxon rank-sums which were calculated by using permutation tests.
The study was performed using the data of 388 prostate patients from theRT01 trial (ISRCTN 47772397).
Results: The only endpoint which was significantly correlated to the doseto the anal surface was subjective sphincter control. Significant correlations were found for the lateral extent of the dose distribution, DSH and themean dose. The strongest correlations were found for lateral extent at 51 Gy(p=0.01) and dose distributions where the relative lateral extent of the anal
surface receiving at least 51 Gy did not exceed 56% were beneficial. The
mean dose was also significantly correlated to outcome (p=0.047) and patients who received a mean dose of 45.1 Gy or greater to the anal surface
had a significantly higher complication risk. In a previous study no significant
correlations between the dose to the entire anorectal surface and subjective
sphincter control were found.
Conclusions: Subjective sphincter control was significantly correlated to thedose to the anal surface. Volumetric measures such as DSH and mean dose
as well as spatial aspects such as the lateral extent of the dose distribution
were important for outcome. Mean doses greater than 45 Gy to the anal surface should be avoided as this results in a significant increase in complication
risk. Furthermore, the lateral extent of the dose distribution at 51 Gy should
not exceed 56%.
449 poster
INDIVIDUALISING STEREOTACTIC LIVER RADIOTHERAPY FOR
LARGE TUMOUR VOLUMES USING LIVER NORMAL TISSUECOMPLICATION PROBABILITY (NTCP) ESTIMATION
I. Blasiak-Wal1 , V. N. Hansen1 , M. Hawkins2
1
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Joint Department of Physics, Sutton, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department ofRadiotherapy, London, United Kingdom
Purpose: Most radiotherapy prescriptions are decided prior to planning andmaintain fixed dose and fractionation. Liver irradiation is challenging due tosensitivity of normal liver to radiation. NTCP modelling can be used to estimate risk of radiation induced liver disease. The aim is to investigate planning techniques and deliver safe, but as high as tolerable doses to large liver
metastases based on normal liver NTCP criteria.
Materials: Forward planned multiple field plans were generated and delivered for 11 colorectal cancer patients with unresectable liver disease. Eachplan had an individualised planning target volume (PTV) defined using tumour
motion information from 4DCT and cine MRI scans. Each patient was considered for individualised dose according to effective volume of uninvolved
liver irradiated (Veff). The dose was stratified in 3 dose bins: Veff <30% =40-60Gy, Veff 30-50% = 35-50Gy and Veff 51-70% = 30Gy. The fractionationand time were fixed 10 fractions over 2 weeks. In order to increase therapeutic ration, the highest safe dose based on normal liver NTCP<1% using Lyman-Kutcher-Burman model (Dawson et al 2002) was prescribed while
maintaining the dose constrains for uninvolved liver and organs at risk (OAR):
gastro-intestinal tract (small bowel, stomach, duodenum, oesophagus) 37Gy
to 1cc, kidneys (combined1/3 <18Gy) and spinal cord (34Gy max).
Results: Photon energies 6-15 MV were used for the plans with no specificbeam number, the median number of beams used was 4 (3-5). Beam arrangement was chosen to spare maximum volume of normal liver and to create steep dose gradient near OAR outside PTV. PTV mean = 294cc, (range
69 674cc) Veff mean = 41%, (range = 11.8 55.7%). Tumour lesions awayfrom OAR can be escalated to higher doses. 2 out of 11 patients with isolated
from OAR targets received relatively high doses (50 and 60Gy). 3 patients
had the prescription restricted by normal liver Veff and had the tumours irradiated to doses below 40Gy. The PTV volume in all those 3 cases exceeded
400cc and the Veff was ≥ 50%. The remaining 6 patients with targets overlapping with OAR (small bowel, duodenum and stomach) received doses of
35 40Gy, despite the Veff permitting dose escalation.
Conclusions: Radiotherapy can be safely delivered to large volumes of disease, however if liver metastases PTVs overlap OAR, critical structures (especially gastro-intestinal tract) limit the dose escalation and target volumes
become less important. If PTVs are away from OAR the limiting constrain is
the normal liver Veff and therefore the size of the tumour matters.
450 poster
UTILISING BIOLOGICAL-BASED IMRT TO REDUCE PAROTID DOSE
AND ACUTE XEROSTOMIA IN RADICAL RADIOTHERAPY OF THE
LARYNX.
N. Anderson1 , M. Rolfo1 , V. Khoo2 , D. Lim Joon1 , M. Wada1
1
AUSTIN H EALTH, Radiation Oncology, Heidelberg West, Melbourne,
Australia
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom

P OSTER

S 181

Purpose: Intensity modulated radiation therapy (IMRT) is frequently used in
the management of head and neck malignancies. Clinical outcomes correlatestrongly with dose parameters to critical structures in this region such as theparotids which are largely responsible for salivary production. Multiple studies have reported the importance in minimising incidental parotid irradiation,and thereby reducing the acute and late effects of treatment-induced xerostomia. Geographical differences in high dose treatment volume and parotids insquamous cell carcinoma of the larynx can often facilitate reduced incidental
parotid irradiation. Recent advances in biologically based treatment planninghave enabled further parotid avoidance compared to conventional IMRT practice. A correlative study of clinical outcomes was undertaken to quantify theclinical benefit of this dosimetric improvement.
Materials: Twenty-nine patients with SCC larynx were prospectively analysed
for dosimetry and acute salivary toxicity. Seventeen patients were planned
using physical based IMRT (CMS XiO), and twelve patients using biological based IMRT (CMS Monaco). Unilateral whole parotid and bilateral wholeparotid mean dose was recorded. Patients were reviewed weekly during treatment, and acute salivary toxicity scored using Common Terminology Criteria
for Adverse Events (CTCAEv3). Grade 2 and 3 salivary toxicity incidence wasdeemed clinically significant, and reported for comparison.
Results: Significant dose differences were seen between the two planningalgorithms: left parotid (XiO = 24.4Gy, Monaco = 19.8Gy, p = 0.015), rightparotid (XiO = 24.4Gy, Monaco = 20.0Gy, p = 0.006) and bilateral wholeparotid mean doses (XiO = 24.4Gy, Monaco = 19.9Gy, p = 0.004). Overall,Monaco derived plans derived a significant reduction in dose to the parotids.
Monaco derived plans resulted in a significant reduction in acute Grade 2
salivary toxicity in week 6 of 37.4% (55.6% to 18.2%, p = 0.047) and week 7
of 50.0% (75% to 16.7%, p = 0.031), when compared to XiO derived plans.
No Grade 3 toxicity events were recorded in either group.
Conclusions: Treatment induced acute xerostomia may negatively impact
quality of life throughout and post radical head and neck radiotherapy. Current IMRT practice provides an excellent platform for parotid dose avoidancein laryngeal irradiation as evidenced by the absence of grade 3 toxicity in thiscohort. However biological based treatment planning has facilitated further
parotid dose avoidance. This is particularly important in optimising dose reduction, where incidental irradiation has shown to facilitate parotid shrinkage,and subsequent dose intensification beyond planning. This study demonstrates the importance of minimising dose beyond reported recommendations
to deliver optimal clinical benefit with an early correlation for reduced acutesalivary toxicity and further study.
451 poster
FEASIBILITY OF TCP-BASED DOSE-PAINTING BY NUMBERS AT
THE EXAMPLE OF A PROSTATE CASE WITH [18]F-CHOLINE PET
T. Dirscherl1 , M. Rickhey2 , L. Bogner1
1
U NIVERSITÄTSKLINIKUM R EGENSBURG, Department of Medical Physics inRadiation Oncology, Regensburg, Germany
2
K LINIKUM I NGOLSTADT G MB H, Institut für Medizinphysik, Ingolstadt,
Germany
Purpose: Sophisticated imaging techniques like PET have become invaluable tools for staging and target delineation of various tumor entities, but theyalso provide functional information about the heterogeneous distribution of
biological parameters within a tumor. A biologically adaptive radiation treatment method, which maximizes the TCP, is shown. Functional imaging isused to derive the three-dimensional distribution of the parameters of thelinear-quadratic model and to acquire a heterogeneous dose prescription interms of dose-painting by numbers.
Materials: Adapted from a method for selective dose escalation under theguidance of spatial biology distribution, a model, which translates heterogeneously distributed radiobiological parameters into voxelwise dose prescriptions, was developed. At the example of a prostate case with 18 F-choline PET
imaging, different sets of reported values for the parameters were examined
concerning their resulting range of dose values. Furthermore, the influenceof each parameter of the linear-quadratic model was investigated. The uptake of choline can potentially be correlated with the proliferation rate of thetumor cells, therefore a correlation between PET signal and proliferation as
well as cell density was assumed. Using our in-house treatment planningsoftware Direct Monte Carlo Optimization, a treatment plan based on the obtained dose prescription was generated. The feasibility of applying such aheterogeneous dose distribution was investigated by means of a dosimetricevaluation with Gafchromic EBT films and gel dosimetry.
Results: For every considered set of radiobiological parameters, the model
suggested a dose escalation exceeding 100 Gy in the prescription, when a
TCP of 99% was aimed for. With a less ambitious demand for the TCP, oneof the parameter sets resulted in a dose range of 87.1 Gy to 99.3 Gy, stillyielding a TCP of 94.7%. The TCP of the plan decreased to 73.5% after
optimization based on that prescription. The figure shows the resulting dose
distribution (right) together with the PET imaging (left) and dose prescription(middle). The dose difference histogram of optimized and prescribed dose
revealed a mean of -1.64 Gy and a standard deviation of 4.02 Gy. Dosimetricverification showed a reasonable agreement of planned and delivered dose.

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P OSTERW EDNESDAY, M AY 11, 2011
not improve on cEUD. We conclude that cEUD may be a simple and usefulmetric for treatment plan review, but needs further testing. Partially supported
by NIH R01 grant CA85181.
453 poster

Conclusions: If the distribution of radiobiological parameters within a tumor
is known, this model can be used to create a dose-painting by numbers plan
which maximizes the TCP. It could be shown, that such a heterogeneous dose
distribution can be planned and applied.
452 poster
TESTING WHETHER THE CELL-KILL-BASED EQUIVALENT UNIFORM DOSE (CEUD) FORMULA PREDICTS LOCAL CONTROL FOR
NON-SMALL-CELL LUNG CANCER
A. Zuniga1 , A. Hope2 , P. Lindsay2 , J. Bradley3 , J. Deasy1
1
M EMORIAL S LOAN -K ETTERING C ANCER C ENTER, Department of Medical
Physics, New York, USA
2
P RINCESS M ARGARET H OSPITAL, Department of Radiation Oncology,
Toronto, Canada
3
WASHINGTON U NIVERSITY S CHOOL OF M EDICINE, Department ofRadiation Oncology, St. Louis, USA

Purpose: To investigate the predictive power of cell-kill based equivalent uniform dose formula (cEUD) for radiotherapy local control of non-small cell lungcancer (NSCLC). If this were established, cEUD could be used as one input
into treatment planning decision support.
Materials: 57 patients, treated at Washington University in Saint Louis, using
three-dimensional conformal radiation therapy (3DCRT) and standard fractionation for NSCLC (typically 1.8 Gy/day), had isolated lesions with local
control status determined radiographically on followup. Of these, 22 patients
failed locally during followup (median followup time for all patients was 20months). Monte Carlo-corrected dose distributions were used for the analysis. The cell-kill based model for equivalent uniform dose (as suggested
by Niemierko) was evaluated using univariate logistic regression analysis fordifferent values of the (unknown) surviving fraction at 2 Gy (SF2). Mathematical models were built using a logistic regression function with cEUD and thelogarithm of the gross target volume (GTV) volume as input parameters. A
Poisson-based tumor control probability (TCP) model with radiosensitivity (alpha) and an effective density of clonogens as internal parameters was also
investigated. The capability of the models to predict local control correctly
was tested by evaluating the area under the receiver operating characteristic
curve (AUC) for each model fit.
Results: Univariate logistic regression results for the simplest cEUD calculation correlated significantly with local control for SF2=0.5 (p<0.01; Spearman rank, Rs=0.33; and AUC=0.69). cEUD for SF2=0.8 gave the best univariate correlation (p=0.001, Rs=0.4 and AUC=0.73). The Poisson-modelbased TCP function also correlated with local control (p=0.001, Rs=0.4 and
AUC=0.74), but no better than cEUD. The figure plots the logistic regression
model of cEUD for SF2=0.8; bars represent the observed rates of local control.

CONSEQUENCES OF NANOSCALE ENERGY DEPOSITIONAROUND HEAVY ATOM NANOPARTICLES: IMPLICATIONS FOR
RADIOTHERAPY
S. McMahon1 , W. Hyland2 , M. Muir3 , J. Coulter1 , S. Jain4 , K. Butterworth1 ,G. Schettino1 , G. Dickson1 , A. R. Hounsell4 , J. O’Sullivan4 , K. Prise1 , F.
Currell3
1
C ENTRE FOR C ANCER R ESEARCH & C ELL B IOLOGY, Q UEEN ’ S U NIVER SITY B ELFAST , Belfast, United Kingdom
2
S CHOOL OF P HARMACY, Q UEENS U NIVERSITY B ELFAST, Belfast, United
Kingdom
3
D EPARTMENT OF P HYSICS AND A STRONOMY, Q UEEN ’ S U NIVERSITY,
B ELFAST, United Kingdom
4
B ELFAST C ITY H OSPITAL, Belfast, United Kingdom
Purpose: The use of contrast agents in radiotherapy offers the potential tosignificantly improve conformation of dose to tumour volumes by providing
a much clearer difference in mass energy absorption between healthy andcancerous tissue. As a result, there is a considerable interest in the effects
of agents which bear heavy elements (such as cis-platinate compounds, andgold nanoparticles) on the radio-sensitivity of cancer cells. The effects ofthese contrast agents are suggested to derive from their high mass energy
absorption coefficient increasing the amount of energy deposited in the target
volume. However, there is a discrepancy between the physical increase in energy deposit and the degree of radio-sensitisation which has been observedin in vitro cellular studies, with significant increases in cell killing observedat concentrations orders of magnitude lower than physically predicted.In thiswork, dose distributions were modelled on the nanometre scale in the vicinity of a gold nanoparticle, to determine if small-scale inhomogeneities were
responsible for the significant observed biological effectiveness.
Materials: Dose distributions following X-ray exposure were modelled aroundindividual gold nanoparticles using the Geant4 simulation toolkit, along with
its low-energy G4DNA extensions. These dose distributions were then used
as inputs for models which have been developed to predict the effects ofhighly inhomogeneous doses, including the Local Effect Model, to map thesedose distributions to cell survival outcomes.
Results: These simulations show an extremely large variation in dose in thevicinity of irradiated gold nanoparticles, with doses of hundreds of Gy deposited near their surface following a single ionising event. These extremely
high localised doss lead to predictions of a significantly larger increase inbiological effectiveness than simply considering average dose increases, by
as much as an order of magnitude. These results were found to be in good
agreement with experimentally observed in vitro cellular experiments for cells
treated with 1.9 nm gold nanoparticles before exposure to 160 kVp X-rays.
Conclusions: This model is the first which accurately predicts the radiation
sensitizing properties of gold nanoparticles from physical dose distributions.
It indicates that the majority of the sensitizing effects are the result of thelarge number of low-energy short-range secondary particles, which deposit
extremely high doses in the vicinity of the nanoparticle. This has significant
implications for future therapeutic approaches, as it means that the nanoscale
localization of the particles is of great importance to their sensitizing properties.

Young scientists ESTRO Poster Session: IGRT 4D
454 poster
COMPARATIVE PERFORMANCE OF RESPIRATORY MOTIONPREDICTORS FOR REAL-TIME TUMOR TRACKING
A. Krauss1 , S. Nill1 , U. Oelfke1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Heidelberg, Germany

Conclusions: For this dataset, cEUD of the GTV correlates well with local
control of non-small cell lung cancer. TCP is also a good predictor, but does

Purpose: Prediction of respiratory motion is essential for accurate real-time
tumor tracking of lung or liver tumors to compensate for system latenciesof typically several hundred milliseconds. We aim to guide the choice ofa suitable prediction model by comparing the performance of four popular
predictors for various system latencies and sampling rates. Because computation times for model parameter selection on an patient specific basis areprohibitive in clinical settings, we evaluate the feasibility of selecting a patientindependent set of model parameters, which yields good predictions for every
breathing motion trace.
Materials: The considered predictors were linear regression (LR), neural network prediction (NN), kernel density estimation (KDE) and support vector regression (SVR). We used 12 traces of 3D lung tumor motion sampled at 30Hz.
Prediction errors were quantified as root mean squared errors between predicted and actual tumor motion. We evaluated latencies of 200ms, 400ms,

W EDNESDAY, M AY 11, 2011
600ms and sampling rates of 30Hz, 15Hz, 7.5Hz. To guarantee robustness against amplitude variations and baseline drifts, we subtracted runningmeans and normalized running variances to one in a sliding window preprocessing step. We tested three training schemes: (1) stationary fixed training
data window of 40s length, (2) adaptive training window updated every 3s,
length of 40s fixed, (3) adaptive-expansive training window updated every
3s, length iteratively enlarged to 60s. We addressed the problem of model
parameter selection by applying a grid search in the model parameter spacefor each predictor, all latencies, all sampling rates and all training schemes.
For each grid point, prediction errors were evaluated on the time window from43s to 83s of the breathing patterns, thus allowing 3s of training time after the
40s training data collection period. The optimum patient-independent model
parameter set was chosen such that the mean prediction error over the 12
breathing traces was minimized.
Results: The prediction accuracy decreased by less than 10% when changing from model parameters optimized patient-specifically to the patientindependent model parameter set. Figure 1 summarizes patient-averaged
prediction errors for 15Hz sampling rate using the patient-independent model
parameters. Apparently all predictors approximately halved prediction errors
when compared to using no prediction. The NN slightly outperformed theothers with an improvement of around 10% compared to LR. The adaptiveexpansive training performed advantageous. Almost no dependency on thesampling rate could be observed.

P OSTERS 183

rotated together over 90 degrees. The last 20 degrees were sampled onlywith the leading source. In this way both single and dual source imaging
systems described the same trajectory. A large amount of different image
acquisition settings, varying gantry speed and image frame rate, were simulated. The breathing was modeled as a sine wave and also Cyberknife patient
tumor track data was used as breathing signal in the simulation. The projection images were binned in 8 phases and a bin was scored when a projection
image was acquired. Angular bins of 1 degree were used. To evaluate thereconstructed tomographic image quality in function of moving objects, digital reconstructed radiographs (DRR) were generated for both single and dual
source 4D CBCT. A 6 cm spherical object moved according to the CyberKnife
tumor track data. The acquisition settings for this simulation were 0.5 /s and1 /s gantry speed with 6 fps.
Results: The completeness in phase binned projection data was not alteredwhen using dual source scanning, while we reduced the scanning time with45%. We found that increasing the frame rate did not induce any difference
between single and dual source CBCT scanning and only will increases thedose. For a sine wave breathing signal, an increase in projection completeness was seen for increasing breathing frequency. For the Cyberknife data
the increase in projection data only became linear for a low gantry speed(<1.5◦ /s). The 4D reconstruction from the DRRs generated for a moving
sphere, showed a better shape conservation for 4D dual source CBCT with
1 /s rotation speed in comparison with single source CBCT after reconstruction. When the gantry speed was lowered to 0.5 /s, the reconstructed spherebecame equal for both image acquisition methods. The shape of the FDK
reconstructed object was assessed based on the transversal outer contour(Fig. 1). The 4D dual source CBCT acquistion for 1◦ /s gantry speed rotationagreed better (or best) with the reference contour.

Conclusions: By using dual source cone-beam CT for 4D CBCT imaging
we can acquire the same amount of projection data in 55% of the scan timecompared to single source CBCT. Due to the use of less breathing cycles,
the geometric accuracy improved and the blurring in image quality decreasedusing fast 4D dual source CBCT acquisition.
456 poster
VISUAL FEEDBACK OF LIVE OPTOELECTRONIC BODY SURFACEMEASUREMENT FOR MOTION AND POSE MANAGEMENT DURING
RADIOTHERAPY
J. Parkhurst1 , G. Price1 , P. Sharrock1 , T. Marchant1 , A. Jackson1 , C.
Moore1
1
C HRISTIE H OSPITAL NHS T RUST, Manchester, United Kingdom
Conclusions: Thorough parameter tuning allows choosing a patientindependent model parameter set, such that all predictors are able to adapt tothe patient specific breathing patterns and yield almost equally good prediction accuracies. The impact of both the sampling rate and adaptive retraining
is surprisingly small.
455 poster
FAST 4D CONE-BEAM CT IMAGING USING THE DUAL SOURCE
ORTHOGONAL KV SYSTEM OF THE VERO SYSTEM
K. Poels1 , T. Depuydt1 , D. Verellen1 , M. De Ridder1
1
U NIVERSITAIR Z IEKENHUIS B RUSSEL, Brussels, Belgium
Purpose: To improve image quality in 4D CBCT imaging by using a fast dual
source system integrated on real-time tumor tracking O-ring linear accelerator.
Materials: To study the principal of dual source CBCT acquisition for 4D
imaging we did a computer simulation calculating the completeness of projection data for both single and dual-source 4D CBCT. Here for we scored thesampling of the breathing signal based on the breathing phase and the angular position of the acquisition source. In a first simulation no tumor motion
within a phase bin was assumed. A single cone-beam kV source was assumed to rotate over 200. A second kV source was added and both sources

Purpose: Patients undergo complex motion during radiotherapy irradiation that is undetectable using X-ray imaging or conventional video monitoring (Moore et al. DOI: 10.1016/S0360-3016(03)00079-8, Moore et al.
10.1109/MEDIVIS.2006.1). Attempts have been made to try and ensure
patients control their breathing and maintain a fixed position during treatment (Venkat et al. DOI: 10.1088/0031-9155/53/11/N01, Cervino et al. DOI:
10.1088/0031-9155/54/22/007). However, many patients are often asked tosimply ’keep still’ without further qualification or quantification. We describe
a true real-time live feed-back device using 3D optical body surface sensing designed to give patient and radiographer easily appreciated, large area
information about body motion and pose during treatment.
Materials: An in-house tri-colour optical sensor, installed in a treatment
room, was enhanced under NIHR project K021 to generate densely populated, real-time surface data using Fourier profilometry (Moore et al. DOI:
10.1016/S0360-3016(03)00079-8). To intuitively show motion, either the native 3D body shape or a reduction to a dynamic flexing lamina is displayed
from the point of view of the patient looking down their body. Laminas are
created by the subtraction of a reference surface from each consecutive surface in real-time to show the deviations in position across the patient’s body(left in figure). The features shown in the patient displays are tailored to individual ability/health. Thresholds indicate the bounds of acceptable motion.
For subjects who have difficulty interpreting the motion of the lamina, this isfurther condensed into a ’traffic-light’ bar-indicator (right in figure). PersonalS 184

P OSTERW EDNESDAY, M AY 11, 2011display is provided as an option. Radiographers can select all or part of thesurface for detailed monitoring. Members of the UK NCRI Consumer Liaison
Group (CLG) are formally engaged in the project.

W EDNESDAY, M AY 11, 2011

P OSTERS 185

some patients an extra CBCT within a treatment fraction is required. Large
breast volumes may have a severe effect on the quality of these treatments
and further analysis on a larger patient group evaluating the intrafractional
movement of the tumor is required.
459 poster

Conclusions: We have presented a novel method to track the 2D motion ofa lung tumour in CBCT projections and to perform a motion compensatedreconstruction of the tumour. We have produced promising looking resultson simulated data from a real patient. We are now working on applying thismethod to real CBCT data acquired as part of clinical practice.

FIDUCIAL MARKER BASED CBCT GUIDED STEREOTACTIC RADIATION THERAPY FOR LIVER TUMORS EMPLOYING TRAJECTORY
ESTIMATION
E. Worm1 , W. Fledelius1 , M. Høyer1 , J. E. Nielsen2 , L. P. S. Larsen2 , P. R.
Poulsen1
1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Radiology, Aarhus C,
Denmark

458 poster

Results: Real-time performance of 23, 512x512 point 3D surfaces per second, either native or reduced to lamina visualisation was achieved. NCRI CLG
Feedback is very positive with a preference for the anonymity of reduced lamina display for patients strongly expressed. Following successful laboratory
testing a clinical system has been installed and is operational in a treatment
room. Ethical approval has been granted to conduct a clinical study using thedevice.
Conclusions: We describe a true real-time 3D optical body surface sensor
for direct patient feedback and radiographer motion and pose management
during radiotherapy. The performance of 23 dense surfaces per second issufficient to capture and analyse shifts and physiological motion live during
treatment. Most importantly, a method for intuitively visualising motion for patients asked to ’keep still’ during irradiation is provided, with detail customised
to the patient’s ability. Simple thresholds are used to indicate the range of motion that is acceptable.
457 poster
LUNG TUMOUR TRACKING AND MOTION COMPENSATED RECONSTRUCTION IN CONE BEAM CT
J. McClelland1 , J. Martin1 , D. Hawkes1
1
U NIVERSITY C OLLEGE L ONDON, Centre for Medical Image Computing(CMIC), London, United Kingdom
Purpose: Lung tumours can appear blurred in CBCT scans due to respiratory
motion, and can be difficult to detect in the 2D CBCT projections because they
can become obscured by high intensity structures such as bones. We havedeveloped a method of enhancing the tumour appearance in the 2D CBCT
projections, tracking and correcting for the 2D motion of the tumour in eachprojection, and then performing a motion compensated reconstruction of thetumour.
Materials: The ’blurred’ tumour plus approximately a 10 mm margin is delineated in the original CBCT scan. Simulated projections are then generated
from just the delineated volume, and from the original CBCT scan with thedelineated volume set to the same intensity as air. To enhance the appearance of the tumour in the 2D projections the simulated projections that do notinclude the delineated volume are subtracted from the original CBCT projections. This should remove all of the stationary anatomy not included in thedelineated volume from the projections. Any moving anatomy not included in
the delineated volume (e.g. the diaphragm) will not be correctly subtracted
and will create artefacts in the enhanced projections. To minimise these artefacts the projections from just the delineated volume are used as a mask, andpixels outside the mask are set to 0.In order to track and correct for the 2D
tumour motion, the enhanced projection is translated to find the best alignment with the ’blurred’ tumour in the projection of the delineated volume. Thistranslation is applied to the original projections, and the translated projections
are used to reconstruct a motion corrected CBCT volume where the tumour
should appear less blurred (although any anatomy that does not move withthe tumour will be blurred). If necessary, the same region that was previously
delineated can be extracted from the motion corrected CBCT and used togenerate simulated projections of the delineated volume with a less blurred
tumour. These may enable more accurate tracking of the 2D tumour motion.
This whole process can potentially be iterated to improve the quality of the
motion corrected CBCT volume.
Results: We have performed a feasibility test of the presented method on
simulated data. The data was simulated from a deformable registration based
motion model derived from Cine CT data from a real lung cancer patient.
Promising results were obtained, as shown in Figure 1.

ASSESSMENT OF INTRA-FRACTION MOTION DURING PARTIAL
BREAST IRRADIATION.
N. Bouzeya1 , S. Vreeswijk1 , P. Elkhuizen1 , J. J. Sonke1 , C. Vliet van Vroegindeweij1 , P. Remeijer1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

1

Purpose: A study directed at implementing pre-operative image guided accelerated partial breast irradiation (PAPBI) without compromising local control
in early breast cancer patients has recently been implemented in our institute.
Accurate tumor delineation and radiation dose delivery is imperative for thesepatients. A marker placed during biopsy aids target volume delineation andimage guidance using cone beam CT (CBCT). Intra-fraction movement is oneof the residual uncertainties after image guidance. The purpose of this study
is to quantify such motion.
Materials: Patients ≥60 yrs with a unifocal cT < 3cm pN0(sn) M0 breast tumor are eligible for this study. Sentinel node procedure is performed before
RT. Patients are treated with a dose of 10 x 4 Gy over 12 days. A wide local
excision is performed 6 weeks after RT. During the biopsy procedure a fiducial marker is placed in the tumor. The CTV margin is 2cm. A further marginof 0.5cm for set-up errors is added (PTV). The marker is used for daily setup
correction using CBCT. Patients were irradiated with IMRT delivered in ≥3
beams using 6 18 MV photons. Prior to irradiation a CBCT is acquired andregistered to the bony anatomy first and then to the marker. Setup correction was performed based on the marker position. Another CBCT is acquired
post treatment to determine intrafraction movement. When intrafraction translations ≥ 0.5cm were observed in any direction, an extra CBCT was acquired
halfway within the fraction and was also scheduled for subsequent fractions.
We also calculated the breast volume for each patient and evaluated a possible correlation with intrafraction motion. Group mean, systematic (Σ) andrandom (σ ) standard deviations were determined for initial setup errors andintrafraction motion.
Results: Eight patients were evaluated. The initial and intrafraction setup is
shown in table 1. The infra-fraction movement was substantial. Therefore
4 patients required extra scans halfway treatment for the subsequent fractions. The largest initial setup and intrafraction errors were observed in theanterior/posterior (AP) direction, possibly due to the effect of gravity on thelarger breast volumes. Although no correlation was found between breast
volume and large intrafraction motion, this could be due to the small numberof patients.

Conclusions: The use of a fiducial marker aids an optimal tumor localization allowing delivery of high dose irradiation. The results indicate that for

Purpose: Accurate image guidance is vital for precise delivery of stereotactic
body radiation therapy (SBRT) to liver tumors. Using implanted fiducial markers it is possible to obtain an accurate estimate of the 3D target trajectory fromthe individual cone beam CT (CBCT) 2D projections. The aim of this study
was to demonstrate how this adds detailed information about tumor position
compared to set-up based on a reconstructed 3D CBCT volume.
Materials: Three patients each receiving three fractions of SBRT for liver
metastases at a conventional linear accelerator had two gold markers implanted in the rim of the tumor. A CBCT scan showing the marker position
in all projections was acquired immediately before and after treatment. Each
CBCT scan had approximately 650 projections acquired during a full gantry
rotation in 55-60 seconds. On-line manual registration was performed between the CBCT volume and the mid-ventilation phase of the 4D planning
CT to calculate the required couch shifts for marker-based setup. An additional registration based on the bony anatomy was used to quantify baseline
shifts of the markers relative to the spinal vertebrae. Off-line, template based
marker segmentation was performed in all CBCT projections and used tobuild a 3D probability density function for each marker from which the 3D
marker trajectories were estimated. The mean position along the trajectories
relative to the planned marker position as defined on the planning CT wasused as an alternative way to calculate the required couch shift. This wascompared with the on-line CBCT registrations used at treatment.
Results: Respiratory induced motion-smearing of the gold markers in the
CBCT volumes (Fig. 1) made an auto-match unfeasible. Furthermore, thesmearing introduced some undesirable subjectivity in the manual imageguidance process. Defining the mean marker position from the 3D trajectoryas the true optimal baseline gives an objective and more correct measure of
the required couch shift. Fig. 1 (bottom) shows the trajectory of a marker
and the result of the different match-strategies obtained by analyzing a single
CBCT scan. The mean absolute set-up error by the manual CBCT volume
registrations on the markers (line 2, Fig. 1) relative to the optimal baseline(line 1, Fig. 1) was 0.7 ± 0.6 [0.0; 2.7] mm (mean ± SD [total range]), 1.3 ±0.8 [0.1; 3.0] mm, and 0.5 ± 0.4 [0.0; 1.5] mm in the Anterior-Posterior (AP),Cranio-Caudal (CC), and Left-Right (LR) directions respectively. For comparison the mean magnitude of the set-up error for bony anatomy (compare line
1+3, Fig.1) would be 4.9 ± 1.9 mm (AP), 9.9 ± 6.2 mm (CC), and 3.5 ± 3.0
mm (LR).

Conclusions: Tumor motion is a challenge in liver SBRT. A manual CBCT
match on implanted markers is feasible but prone to subjectivity and error.
This problem can be solved by extracting the full 3D marker trajectory fromthe CBCT projections adding valuable information to the image guidance process.
460 poster
RADIOPAQUE MARKER MOVEMENT DURING CBCT AS A PREDICTOR OF INTRA-FRACTIONAL MOVEMENT FOR PROSTATECANCER PATIENTS
U. Bernchou1 , S. Agergaard1 , S. Hansen2 , C. Brink13
1
O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
Denmark
2
O DENSE U NIVERSITY H OSPITAL, Department of Oncology, Odense,
Denmark
3
U NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark
Purpose: The intra-fractional movement of the prostate constitutes a hindrance for the reduction of the PTV margin for prostate cancer patients. Monitoring the movement of the prostate during treatment is a promising but (inmost institutions) not feasible solution. However, the projection images ofthe pre-treatment CBCT provide information about the motion of the target
immediately preceding the treatment [IJROBP 72, 1587, 2008]. This motion
information can be extracted from any standard CBCT scan and is thus available in many institutions. In this study we measure the motion of the prostate
during the pre-treatment CBCT and investigate whether this motion is correlated with the intra-fractional movement of the prostate.
Materials: Pre- and post-treatment CBCT scans were made during a number of the fractions (average 11 range 8-12) for 13 prostate cancer patientsduring the radiation treatment course. The scans were acquired over 180 degrees at a frame-rate of 5.5 Hz. Most patients had 3 (one patient had only2) radiopaque markers implanted in the prostate. The pre-treatment CBCTS 186

P OSTERwas registered to the planning CT using a manual seed match and the couch
was adjusted to correct for the positional error. The post-treatment CBCT was
likewise registered to the planning CT and the positional displacement of themarkers was used to assess the intra-fractional movement of the prostate.
For all the 282 pre- and post-treatment scans the 2D marker trajectories in
the projection images were tracked using an automated image analysis algorithm written in MATLAB. For each scan we used a maximum likelihood
estimation to find the most probable 3D Gaussian probability density function
which results in the observed projection data. Based on this probability density function the 3D trajectory of the markers during the CBCT was estimated.
Results: We generally found that the marker movement during the scans(average 31 sec) was very small. The mean standard deviation of the position of the prostate during a single scan was 0.08 mm, 0.17 mm, and 0.24
mm in the left-right (LR), anterior-posterior (AP) and cranial-caudal (CC) directions, respectively. We found no correlation between the motion of themarkers during the pre-treatment CBCT and the corresponding subsequent
intra-fractional movement. The correlation coefficients were -0.05, 0.07, and-0.05 in the LR, AP, and CC directions, respectively. Furthermore, we foundonly very limited correlation between the prostate motion during the pre- andthe subsequent post-treatment CBCT. The correlation coefficients were 0.22,
0.24, and 0.12 in the LR, AP, and CC directions, respectively.
Conclusions: It is tempting to exploit the pre-treatment CBCT to predict the
intra-fractional movement of the prostate but, unfortunately, we have foundno correlation between the intra-fractional movement and the motion of theprostate immediately prior to treatment.

Young scientists ESTRO Poster Session: Rotational IMRT
461 poster
TOWARDS POSITION-VERIFICATION USING CT IMAGES RECONSTRUCTED FROM VMAT PORTAL IMAGES
G. Poludniowski1 , M. Thomas1 , P. Evans1 , S. Webb1
1
I NSTITUTE OF C ANCER R ESEARCH & R OYAL M ARSDEN NHS T RUST, Joint
Department of Physics, Sutton, United Kingdom
Purpose: Volumetric Modulated Arc Therapy (VMAT) has become a hot-topic
of research in recent years. Portal images acquired with an Electronic Portal
Imaging Device (EPID) during a treatment fraction form an incomplete conebeam CT (CBCT) data-set. Previously we have shown that a set of such portal images, when used in a modified CBCT algorithm, allows a recognizable
CT-volume and anatomy to be reconstructed. Such "VMAT-CT" reconstructions therefore provide a potential tool for treatment position-verification. We
show that a tumour mass in a lung cancer patient is visible within a VMAT-CT
volume and demonstrate the principle of image registration between such a
volume and a planning CT scan.
Materials: The methodology for VMAT-CT reconstruction has been presented
previously (G Poludniowski et al 2010 Phys. Med. Biol. 55 5635). We apply this method to data acquired during hypofractionated VMAT treatmentsof small-volume lung cancer patients (60 Gy in 8 fractions). An Automatic
Breathing Coordinator was used during treatment. The portal images wereacquired using an Elekta linac and EPID. The Multi-Leaf Collimator used forcollimation in each case was a Beam Modulator (40 leaf-pairs, 4 mm leafwidth). The number of portal images acquired during each fraction was typically ~300 over a single 350 degree arc. The reconstruction matrix was
128x128x128 cube of dimension 12x12x12 cm2 and saved as a series of DICOM slices. After import into a Pinnacle Treatment Planning System (Philips
Healthcare) the VMAT-CT volume was registered to the planning CT scan using Image Fusion. This was done automatically using a Normalized Mutual
Information metric.
Results: Lung tumour masses could be visualised on VMAT-CT reconstructions. This is illustrated by the figure. An axial slice of a planning CT scanis shown (left) along with a slice from of VMAT-CT reconstruction (right). The
shape of the mass in the VMAT-CT slice corresponds quite closely to thatin the planning scan. For this patient an image registration inferred a shiftof 1.3 mm between the planned position of the tumour mass and the actual
treatment position.

W EDNESDAY, M AY 11, 2011

W EDNESDAY, M AY 11, 2011
Conclusions: In terms of VMAT delivery efficiency and treatment time, themaximum leaf speed of the linac is the most significant limiting parameter.
The sensitivity to the limiting leaf speed may have implications for linac design, and could impact upon VMAT treatment planning, in which more complex plans may be produced if delivery constraints are relaxed.

P OSTER

S 187

464 poster
STUDY OF THE EFFECT OF LONGITUDINAL BREATHING MOTIONIN TOMODIRECT TREATMENTS
D. Sevillano1 , C. Minguez1 , J. A. Garcia1 , J. M. Delgado1
1
GRUPO IMO, Tomotherapy Unit, Madrid, Madrid, Spain

463 poster

Conclusions: The visibility of anatomy in VMAT-CT reconstructions suggeststhat this could provide a useful position-verification tool for radiotherapy treatment fractions. Initial investigation has proved promising: automatic image
registration was possible between the VMAT-CT volume and the planning CT
volume for lung-cancer patient data.

REAL-TIME DYNAMIC MLC TRACKING DURING ARC THERAPY:A DOSIMETRIC COMPARISON FOR IRREGULAR AND REGULAR
TUMOUR MOTION
M. Falk1 , P. Keall2 , B. Cho3 , S. Korreman4 , P. Munck af Rosenschöld1
1
R IGSHOSPITALET, Department of Radiation Oncology, Copenhagen,Denmark
2
S YDNEY M EDICAL S CHOOL , U NIVERSITY OF S YDNEY, Radiation Physics
Laboratory, Sidney, Australia
3
A SAN M EDICAL C ENTER , U NIVERSITY OF U LSAN C OLLEGE OF M EDICINE,
Department of Radiation Oncology, Ulsan, Korea Republic of4
R OSKILDE U NIVERSITY, Department of Science Systems and Models,
Roskilde, Denmark

462 poster
THE USE OF A VMAT DELIVERY EMULATOR TO OPTIMIZE
DYNAMIC MACHINE PARAMETERS FOR IMPROVED TREATMENTEFFICIENCY
C. Boylan1 , R. Carl1
1

T HE C HRISTIE NHS F OUNDATION T RUST, North Western Medical Physics,
Manchester, United Kingdom

Purpose: One of the major benefits of VMAT is that treatment times are
significantly reduced compared to fixed-field IMRT. In order to maintain thisefficiency, many planning systems limit the allowable change in leaf and jaw
position between adjacent control points. This ensures that a higher dose
rate can be selected by the treatment linac, thus producing a more stable andtime-efficient VMAT beam. The purpose of this study is to investigate which
dynamic machine parameters are the most important to efficiently deliver a
VMAT plan. Using a software emulator, parameters such as the maximum
leaf, jaw and gantry speed can be adjusted to determine their impact on theoverall treatment time and dose rate efficiency.
Materials: Software was written in Java to emulate the linac control system(LCS) of a VMAT-capable Elekta machine. Currently, Elekta linacs use binned
dose rates and select the appropriate bin and gantry speed in order to deliver
the correct number of monitor units in a time which allows the MLC shape
to reach its next control point. The emulator, like the LCS, contains maximum values for the leaf, jaw, and gantry speed. Gantry inertia is also modelled within the emulator in order to more accurately predict delivery time.
The software emulator was validated against five prostate VMAT plans, whichwere plotted using the Elekta Machine Graphing tool, which allows dynamic
parameters to be recorded every 250ms during delivery. A number of experiments were carried out with the emulator. Increases in maximum allowableleaf, jaw and gantry speed were introduced, and their effect on the overall
treatment time and average dose rate was assessed.
Results: Overall, the emulator showed good agreement in the dose rate /gantry speed selection, and the predicted delivery times were accurate within±2.5s. For five prostate VMAT plans, increasing the maximum allowable leaf
speed from 2.0cm/s to 2.5cm/s produced significantly shorter delivery times(mean -13.8s, p«0.01), and a significantly increased average dose rate (mean
304MU/min increased to 348MU/min, p«0.01). The percentage of monitor
units delivered in the top dose rate bin (600MU/min) was also increased byan average of 11.4% (p«0.01). As shown in figure 1, beyond 2.5cm/s there
is no significant efficiency improvement. No differences were found if thejaw speed was adjusted, indicating that the VMAT delivery is not limited bychanges in jaw position. Increasing the maximum allowed gantry speed from
6.0◦ /s to 7.0◦ /s produced only a modest reduction in the delivery time (mean-1.5s) although this did not show statistical significance.

Purpose: Real-time dynamic MLC tracking for management of intra-fraction
motion uses the multileaf collimator (MLC) to adjust the treatment to the target
movements. Lung tumour motion can be represented by a simple sinusoidal
trajectory but when moving towards clinical implementation of MLC tracking,it is essential to evaluate the delivery accuracy for irregular patient-specifictumour motion in 3D. Irregular motion is more challenging to predict thansinusoidal trajectories and makes it therefore harder to account for the delay
time of the system. In this study the dosimetric accuracy of MLC tracking
delivery to a target moving according to a patient specific tumour motion trace
was evaluated and compared to delivery to a target with sinusoidal motion.
Materials: Lung tumour motion was simulated using the HexaMotion®phantom (ScandiDos) moving according to a 3D patient specific tumour
motion trace (Stanford University, CA) with irregularities and baseline shifts.
The maximum displacement from the isocenter was 3 mm (SI), 8 mm (AP)and 10 mm (LR) and the average speed was 6 mm/s. Evaluation of the HexaMotion prior to the experiments showed position accuracy better than 0.5
mm. The sinusoidal motion was formed using the Respiratory Gating Platform (Standard Imaging Inc) moving in the superior-inferior direction with apeak-to-peak displacement of 2 cm (i.e. a maximum displacement from theisocenter of 1 cm) and a cycle time of 6 s, giving an average speed of 7 mm/s.
The motion phantoms carried the Delta4® dosimetric device (ScandiDos) during delivery of an inversely optimized arc radiotherapy plan. The plan was
created in a research version of EclipseTM 8.8 using the RapidArc®techniquefor a fractionation dose of 2 Gy and used 6 MV, a maximum dose rate of 600
MU/min, a collimator angle of 45◦ , jaw positions of 11 x 11.5 cm and 447 MU.
The plan was delivered using a linear accelerator with a high definition MLC.
The delivery was adjusted to the target motion using MLC tracking, guided
in real-time by the optical part of the ExacTrac®system (Brainlab). Gamma
index was used for the evaluation with measurements of plan delivery to the
Delta4 stationary as reference, and the dose deviation evaluated with respect
to the isocenter dose.
Results: With MLC tracking, the gamma index failure rate was 0.0% with
criteria 3% and 3 mm for both motion patterns and 2.8% (patient specific)
and 0.2% (sinusoidal) with criteria 2% and 2 mm. Without tracking the failure
rate was increased to 13.3% (patient specific) and 19.5% (sinusoidal) with
criteria 3% and 3 mm and to 36.1% (patient specific) and 44.6% (sinusoidal)
with criteria 2% and 2 mm (fig. 1).

Purpose: To evaluate the impact of longitudinal breathing motion in TomoDirect (Tomotherapy inc., Madison, WI) treatments. Treatment parameters of
TomoDirect technique may provoke an interplay effect between breathing andcouch motion due to longer projection times and faster couch speeds than inhelical Tomotherapy.
Materials: Treatment simulations were calculated assuming a 1D model inwhich dose delivered in the longitudinal axis is the convolution of the beam
intensity and the dose profile of that beam during treatment. Beam profilechanges its position during treatment due to couch and breathing motion.
Beam intensity was modelled as a periodic rectangular function with a period equal to the projection time and a width equal to the mean leaf open
time calculated from the modulation factor of the field. Breathing motion wasconsidered to fit a cos4 function. A breathing period of 4 s was used in allof the cases, and all of the calculations were made using a breathing rangeof 0.3 cm and 1 cm. Treatment parameters such as pitch, projection time,
modulation factor and irradiation length were those of a real four-field accelerated partial breast irradiation plan. Dose profiles for the four fields were
calculated assuming the same depth. In order to analyze the influence ofbreathing motion in the dose to the target, five ten-fraction treatments where
simulated using random phases of the breathing cycle for all of the fields forboth ranges and compared to the static case. Profiles of individual fields
where also compared to check a dependency with couch speed.
Results: Dose profiles of simulated plans were compared with those assuming no breathing motion. In the case of a whole ten-fraction treatment it isshown that the motion effect is averaged over the days of treatment, resulting
in dose differences below 0.5% in the central area of the PTV (figure 1). A
wider penumbra occurs in craneo-caudal direction. This effect is dependantof motion range, having a negligible importance when breathing range is 0.3
cm and being of only 1 mm when the range is 1 cm. When single fractions areanalyzed, a modulation of the dose delivered is observed, this interplay effectmight be caused mainly by fields with faster couch speeds. Dose differencesin each fraction do not excess 1% inside the PTV when breathing range is 1
cm, and this effect can increase to a 3% in the PTV limits.

Conclusions: Treating moving targets with TomoDirect is feasible considering that PTV to CTV margins include the whole amplitude of movement of theCTV. Dose differences where acceptable both in a whole ten-fraction treatment and in single fractions. The effect of a single TomoDirect beam is not a
blurring but a modulation of the dose delivered. This effect is then averagedby the same effect of the other beams of the treatment.
465 poster
INVESTIGATION OF A NEW 4D-VMAT PLANNING SYSTEM WITH
COMPARISON TO 3D, GATING AND TRACKING VMAT TECHNIQUES
E. Chin1 , K. Otto2
1
U NIVERSITY OF B RITISH C OLUMBIA, Physics and Astronomy, Vancouver
BC, Canada
2
N ORTHWEST M EDICAL P HYSICS C ENTER, Lynnwood, USA

Conclusions: The results indicate that the MLC tracking method used inthis work very accurately accounted for sinusoidal translations. The patientspecific 3D motion proved somewhat more difficult to correct for, more datais therefore required to clarify if MLC tracking can account for patient specifictumour motion in general.

Purpose: A new 4D Volumetric Modulated Arc Therapy (4D-VMAT) planning system is presented where radiation sparing of organs at risk (OARs)
is enhanced by exploiting the relative motion between the tumour and OARs
during respiration.
Materials: In conventional radiation therapy of moving tumours, a motion
encompassing margin is normally added to the clinical target volume (CTV)
to ensure the tumour receives the planned treatment dose. This results inS 188P OSTERa substantial increase in dose to surrounding healthy tissue and OARs. Our
4D-VMAT algorithm aims to reduce OAR dose by fully incorporating voxelby voxel a priori knowledge of 4D target and OAR motion directly into the
optimization process. During optimization, phase correlated beam samples
are progressively added throughout the full range of gantry rotation. The
resulting treatment plans have respiratory phase-optimized apertures whose
deliveries are synchronized to the patient’s respiratory cycle. 4D-VMAT plans
reduce dose to the OAR by: (1) eliminating the motion margin (2) selectively
redistributing OAR dose over the OAR volume and (3) timing larger dose
contributions (MU) to respiratory phases where greater separations between
the target and OAR occur.Our 4D-VMAT algorithm was tested by simulatinga variety of tumour motion amplitudes (0.5-2 cm) in the cranial/caudal andanterior/posterior directions. 4D-VMAT’s performance was compared against
3D-VMAT, gated VMAT and dynamic MLC tracking VMAT.

W EDNESDAY, M AY 11, 2011
GORTEC-RTOG consensus and were peer-reviewed. DICOM studies weresent to ten TomoTherapy European users. Planning was performed to 50Gy
prophylactic dose and 70Gy therapeutic dose, both in 2Gy-fractions. All 100
plans were compared using the ArtiView software (AquiLab SAS). Experienced TomoTherapy users were compared to "newcomers".
Results:
1. The improvement in dose homogeneity achieved by each IMRT plan
was calculated with respect to a reference DVH (minimally compliant
with the ICRU-62 requirements) by mean of an AUC calculation. HiART planning increased dose homogeneity by 44 to 82%, experienced
users achieving a 72% improvement compared to 61% for newcomers.
2. Dose conformity to the PTV was quantified by the Overlap Ratio (OR)and the Dice Similarity Coefficient (DSC), high values indicating a highconformity of the reference isodose to the PTV contour. Experienced
users consistently achieved 0.75 to 0.80 OR values and 0.85 to 0.90
DSC values.
3. Dose containment outside the target volume was evaluated by the
Dose Gradient (DG), i.e. the sharpness of the dose fall-off. Experienced TomoTherapy users consistently achieved sharper gradients, atleast 2.5%/mm for bilateral volumes and 3%/mm for unilateral tumours.
4. Improvement in dose conformity and dose fall-off allowed experienced
users to decrease the ID by a mean 20% (and up to 30% in somepatients)
Conclusions: Large discrepancies in dose homogeneity remain undisclosed,
not being properly assessed by the HI, CI or CO. A simple AUC calculation,comparing the actual DVH to a reference DVH, measures the improvement
related to IMRT planning. Dose unnecessarily delivered to the NTT is confirmed to be a challenge. Experience in IMRT planning allows a consistent
20% decrease in ID. The present study shows the importance of new evaluation parameters such as the OR, DSC and DG to assess IMRT plan quality
and ID. Further clinical trials investigating rotational IMRT treatments should
encompass these parameters, as large undisclosed discrepancies in ID will
impact on treatment outcome and patients late complications.
467 poster

Results: Results show that OAR sparing of 4D-VMAT was greater than 3DVMAT in all cases due to the smaller PTV margin. Compared to dynamic
MLC tracking VMAT, 4D-VMAT’s OAR sparing is superior only when the relative distance between the PTV and OAR is changing. For gated VMAT, resultscompared to 4D-VMAT are phantom dependent. There was negligible difference in plan qualities for the tested case of motion in the anterior/posterior
axis. For motions in the cranial/caudal axis, gated VMAT’s narrow beamon window reduces the irradiated OAR volume but can also allow hotspots
to accumulate. In contrast, 4D-VMAT can reduce hotspots but at the costof redistributing the OAR dose over a larger volume. Finally for 4D-VMAT,
an increase in tumour motion no longer resulted in greater irradiation of the
OAR as seen in conventional 3D radiation therapy. OAR dose levels were
preserved for increasing target motion along the anterior/posterior axis. For
increasing cranial/caudal motion, the volume of OAR exposed to high doses
actually decreased due to dose redistribution.
Conclusions: Our investigation demonstrated that the 4D-VMAT system has
the potential to improve radiation therapy of periodically moving tumours overgating or tracking methods.
466 poster
HAS ROTATIONAL IMRT REALLY BECOME A TURNKEY TECHNIQUE? THE UPCOMING CHALLENGE OF INTEGRAL DOSE IN
HEAD & NECK CANCER. . .
O. De Hertogh1 , Y. Boukour2 , A. Lisbona3 , D. Van Gestel4 , D. Verellen5
1

C.H. P ELTZER - L A TOURELLE, Radiotherapy, Verviers, Belgium
C.H. P ELTZER - L A TOURELLE, Medical Physics, Verviers, Belgium
3
C ENTRE R ENÉ G AUDUCHEAU, Medical Physics, Saint-Herblain, France
4
U NIVERSITY H OSPITAL A NTWERP, Radiotherapy, Edegem, Belgium
5
U NIVERSITAIR Z IEKENHUIS B RUSSEL, Medical Physics, Brussels, Belgium
2

Purpose: For treating HNC, rotational IMRT easily respects dose constraints
for PTV coverage and for parotid gland sparing. However, it raises new challenges regarding dose homogeneity within the PTV which is inadequately
assessed by the homogeneity, conformity and coverage indexes (HI, CI, CO),and new issues regarding the dose delivered to the non-tumour tissue (NTT)outside the PTV and the integral dose (ID). The purpose of the present study
is: - to develop a new parameter to assess PTV dose homogeneity.- to evaluate the impact of personal experience in terms of dose homogeneity within
the PTV, dose conformity to the PTV and dose containment outside the target
volume. - to calculate the impact of these parameters on the ID.
Materials: Ten locally-advanced HNC cases were randomly selected in our
database. Contours were performed according to the DAHANCA-EORTC-

FLATTENING FILTER FREE BEAMS FOR HYPOFRACTIONATED
RADIOTHERAPY OF LOCALIZED PROSTATE CANCER
S. Lang1 , J. Hrbacek1 , Y. Najafi1 , T. Streller1 , S. Klöck1 , G. Studer1 , K.
Zaugg1 , U. M. Luetolf1 , D. Zwahlen2 1
U NIVERSITY H OSPITAL Z ÜRICH, Zurich, Switzerland
2
K ANTONSSPITAL G RAUBÜNDEN, Chur, Switzerland

1

Purpose: To evaluate the benefits of flattening filter free (FFF) photon beams
in the treatment of prostate cancer.
Materials: Treatment planning was performed for seven patients using four
photon beams of TrueBeam®linear accelerator (Varian Medical Systems,
Paulo Alto): 6 and 10 MV beams with (X6 and X10) and without (X6FFF
and X10FFF) flattening filter in the beam path. For each patient VMAT plans
were prepared in Eclipse treatment planning system (PRO 8.9, AAA 8.9, Varian Medical Systems). The prescribed dose was 19 x 3 Gy = 57 Gy. Plan
objectives for hypofractionation were based on the ongoing phase III CHHIP(Conventional or Hypofractionated High dose Intensity Modulated Radiotherapy for Prostate Cancer) trial protocol. In order to fulfil the criteria either one
or two 360◦ arcs with maximum dose rate of 600 MU/min for flattened beams,
and 1200 MU/min for FFF beams were used, respectively. For the X6 beam
the objectives for the organs at risk were interactively lowered during optimisation, as long as target coverage was not compromised. As soon as asatisfactory set of constraints was achieved, plans for all four energies were
optimized using this set. Plan evaluation was performed according to the constraints used in the CHHIP trial. In addition, monitor units, mean body dose,mean doses to rectum and bladder, conformity index and treatment time wererecorded. Results were compared with a paired Wilcoxon signed-rank test.
Results: For all patients, there was only minor difference in dose distributions
for the four beams. No difference was detected between the four beams withrespect to PTV coverage, conformity and homogeneity. The mean dose to
the body as well as the volume of the body receiving 50 % of the prescribed
dose were decreasing with increasing mean energy (R2 = 0.8275, p < 0.01).
X6FFF beam delivered +3.6 % more dose compared to the X6 beam (p <0.01). In contrary, X10FFF beam delivered 3.0 % (p < 0.01), and the X10
beam 5.8% (p < 0.01) less dose compared to X6 beam. There was no difference in the mean dose to the rectum as well as the dose parameter V68%,
V81%, V95%, V100% for X6, X6FFF and X10FFF. There was a significant
increase in the mean dose to the rectum for the X10 compared to X6 beam
by 2.6 % (p < 0.01). The mean dose to the bladder was increased by 1.3 %for X6FFF and decreased by 2.3 % for X10FFF. No such difference was foundfor X10. For all patients and all energies, V68% for bowel and femoral heads
were below the CHHIP objectives. For plans using a single arc, treatment
time was reduced by 35 % (2SD = 10 %), when using FFF beams. Due tothe limited gantry speed there was no difference in treatment time if two arcs
were used.

W EDNESDAY, M AY 11, 2011

P OSTER

S 189

Conclusions: For RapidArc®treatment plans, FFF beams resulted in dose
distributions similar to flattened beams. X10FFF beam may be advantageous
sparing rectum and bladder and keeping whole body dose as low as possible. The use of FFF beams reduced treatment delivery time. This got more
pronounced using hypofractionation.

Young scientists ESTRO Poster Session: Image
analysis (segmentation and registration)
468 poster
GEOMETRICAL VARIABILITY OF PAROTID GLANDS DURING
RADIOTHERAPY MEASURED WITH DEFORMABLE REGISTRATION
S. R. van Kranen1 , M. van Herk1 , J. J. Sonke1 , C. Rasch1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands
Purpose: Parotid shrinkage during radiotherapy (RT) of head and neck cancer (HNC) is frequently observed and associated with a shift of the gland into
the high dose region, potentially leading to increased toxicity. Plan adaptation
could help to spare this organ at risk. Currently, anatomy changes, if noted,
are visually assessed and occasionally lead to plan adaptation. A techniqueto regularly assess daily geometrical variability (other than manual contouring) is currently lacking. Therefore, as a first step towards clinical implementation of adaptive RT, we have applied an automated method to detect parotidchanges during RT and analyzed daily geometrical variations of volume andposition.
Materials: Daily cone beam CT scans (1 mm3 resolution) for 11 patients with
HNC (T3-T4, 9x oropharynx, 1x base of tongue, 1x oral cavity) were nonrigidly registered with the planning CT (1mm2 in plane, 3 mm slices): in total
342 registrations. We used an in-house developed BSpline deformable registrations algorithm, based on mutual information and regularized on rigidity ofbony anatomy and general smoothness of deformations. Previously the registration error was determined to be ~1 mm SD per axis. For each fraction wemeasured volume and position of the lateral and contra-lateral parotid glands
by propagating the original contours according to the measured deformations.
Results: Deformable registration proved robust and visual inspection showedthat the parotid glands were reasonably well registered. There was no significant difference in parotid reaction at the lateral and contra-lateral side.
A volume reduction was seen for all patients over the full course of treatment: in the last week on average -18.5% (7.7% SD). Linear regression
over parotid volume over time showed an average regression of -0.47%/day(0.26% SD). However, linear regression was often inappropriate: some patients only showed a single moment of volume reduction during treatment(e.g. patient 2 in figure 1). Four out of 8 patients demonstrated a notablecorrelation in volume changes with the administration of chemotherapy (cisplatin and normal saline hyperhydration) around day 1, 22, 43 (see figure 1).
The center of mass of the glands had moved inwards for all patients during
treatment: 0.7, 1.8 and 2.5 mm in weeks 1&2, 3&4 and 5 to 7 relative to theplanning situation (0.8, 0.8, 1.0 mm 1SD).
Conclusions: The measured volume reduction and shift of the parotid glands
into the high dose region was in line with literature. We found, however, large
day-to-day variability, occasionally related to administration of chemotherapy,
and variability between patients. Applying deformable registration to routinely
assess daily geometrical variation of parotid glands is a feasible method toselect patients that may benefit from plan adaptation. However, the exact
moment to acquire a repeat CT for replanning should be chosen with care, inparticular when concommitant chemotherapy is applied.

469 poster
EVALUATION OF ATLAS-BASED AUTO-SEGMENTATION FOR ART
OF PROSTATE CANCER
M. Stock1 , I. Simmat1 , G. Goldner2 , P. Georg2 , W. Birkfellner3 , D. Georg1
1
M EDICAL U NIVERSITY V IENNA, Department of Radiotherapy, Div. Medical
Radiation Physics, Vienna, Austria
2
M EDICAL U NIVERSITY V IENNA, Department of Radiotherapy, Vienna,
Austria
3
M EDICAL U NIVERSITY V IENNA, Center for Biomedical Engineering andPhysics, Vienna, Austria
Purpose: The time-consuming task of CT image segmentation is consideredas the bottle neck in re-planning for adaptive radiotherapy. Organ at risk
and target delineation is still predominantly performed manually and prone tointer-observer variation. In summary, for adaptive radiotherapy based on CT
or CBCT faster contouring procedures will become mandatory. In this study
two atlas-based autosegmentation tools were tested in terms of accuracy andefficiency.
Materials: Twenty patients with variations regarding contrast agent, rectal
balloon, rectal filling and body mass index (BMI) were selected for this study.
Automatic contouring with ABAS (Elekta CMS) and iPlan (BrainLAB) was performed and compared to manual delineation of bladder, rectum and prostate.
First the performance of available DEMO-atlases on CT was investigated.
Second, planning CTs of five patients were selected as new individual atlas
and the automated segmentation of CBCT data, acquired during treatment of
the same patients, was tested. Dice Similarity Coefficient (DSC), generalized
conformity index and indicators for under- and over-segmentation were calculated and compared to inter-observer (IO) variability. Qualitative evaluationin terms of usability of the automatically drawn structures was assessed bya senior radiation oncologist using a visual analogue scale (VAS). In addition
segmentation speed was documented.
Results: The comparison to manual contouring resulted in significant differences of the two systems for bladder (mean over all patients: DSCABAS= 0.86 and DSCiPlan = 0.51) and prostate (mean: DSCABAS = 0.71 and
DSCiPlan = 0.57). The inter-observer variability for the same patient set wasless for bladder (DSCIO = 0.94) and prostate (DSCIO = 0.79). Rectum delineation showed comparable results (mean: DSCABAS = 0.78 and DSCiPlan =0.84) to inter-observer variation (DSCIO = 0.85). The qualitative judgment by
the expert showed similar trends than the coefficients used (e.g. for bladder
VASABAS 6.2 and VASiPlan 1.5). Automatic CBCT segmentation showed
high dependence on the corresponding image quality (mean DSC: bladder
0.66, rectum 0.53, prostate 0.40). Segmentation speed was on average 4
minutes for ABAS and half a minute for iPlan.
Conclusions: Results of atlas-based automatic segmentation for prostatecancer using commercial software are still inaccurate. They require corrections which raise the question about sufficient time savings using these tools.

S 190P OSTER

Further ideas for improvement are inevitable but may not only be restricted
to the registration algorithms but e.g. also to the image quality provided by
CBCT images.
470 poster
A MULTI-PARAMETRIC CHANGE ANALYSIS METHODOLOGYFOR QUANTIFYING TUMOUR CHANGE AND ASSESSING VOXELCORRESPONDENCE QUALITY
J. Hoisak1 2 , C. Menard3 2 , D. Jaffray1 2
1
U NIVERSITY OF TORONTO, Department of Medical Biophysics, Toronto,
Canada2
P RINCESS M ARGARET H OSPITAL, Radiation Medicine Program, Toronto,
Canada3
U NIVERSITY OF TORONTO, Department of Radiation Oncology, Toronto,
CanadaPurpose: Recently developed response assessment methods for quantifying
tumour functional change have superior sensitivity to conventional structuralchange indices but are limited by local registration uncertainty where tumourmorphology changes over time, as is often the case when applied to longitudinal imaging. Such methods must account for disrupted spatio-temporalvoxel correspondences if the change quantification is to be related to tissue properties, or to inform a dose-response model. We hypothesize thata multi-parametric change analysis can quantify tumour structural change atthe voxel level and enable an estimate of voxel correspondence quality prior
to applying functional change analyses. The methodology was demonstrated
with T1-weighted (T1W) magnetic resonance (MR) images acquired as partof a longitudinal imaging study of patients with glioblastoma.
Materials: Twenty-three patients with histologically-confirmed glioblastoma receiving definitive radiotherapy (RT) concurrent with temozolamide
chemotherapy underwent post-contrast axial T1W fast-spin echo imaging on
a 1.5T MR scanner (Signa Excite, GE Healthcare, USA) at post-operative
pre-RT baseline (BL), at the sixth week of RT (WK6), and one month postRT (MO1). Images for each patient were rigidly registered to the BL acquisition, and structural similarity between spatially corresponding voxels wasevaluated using intensity-invariant multi-resolution local histograms. Shannon’s entropy was computed in the local neighbourhood about each voxel,
and was used to identify increased or decreased image structure complexity.
Image change between voxel pairs was then classified according to similarity and complexity thresholds, yielding a 3D volume of T1W image structurechange at the voxel level [Figure 1], computed over multiple acquisition intervals. The methodology was validated by evaluating spatial overlap consistency between the image change volume and the convex hull of the pre- andpost-RT gross tumour volumes (GTV) defined by a radiation oncologist.

Results: The mean spatial overlap index (n=23) with respect to T1W GTV
morphology for the BL-WK6 and BL-MO1 intervals was 0.84 ± 0.07 and0.80 ± 04, respectively. Furthermore, the change analysis revealed heterogeneous patterns of tumour structural change not apparent in conventional
image sequences.
Conclusions: A methodology has been developed for quantifying multiparametric tumour change. Spatial overlap analysis showed that the extent ofimage change was consistent with T1W tumour morphology. Image change
maps can be used to assess voxel correspondence quality prior to the application of analysis methods with inherent sensitivity to local registration uncertainties. Tumour sub-regions identified by multi-parametric change analysis
may also be useful as biomarkers of resistance and response and is the focus
of current research.

W EDNESDAY, M AY 11, 2011
471 poster
CT-BASED AUTO-SEGMENTATION OF LUNG TUMORS SHOWSHIGH OVERLAP WITH ONCOLOGIST DELINEATIONS AND PATHOLOGY
E. Rios Velazquez1 , H. Aerts1 , D. De Ruysscher1 , P. Lambin1
1

MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS -TRICHT, Department of Radiation Oncology, Maastricht, Netherlands

Purpose: In radiotherapy, CT data is acquired immediately before dose delivery. It is known that tumor delineation has a high inter-observer variability. An
automated delineation method would enable a more reproducible tumor definition, to optimize the daily workflow and would facilitate multi-centric trials.
Here we present and compare an automatic CT-based segmentation method,
based on region growing and context, with pathology and with CT/PET manual delineations by five independent oncologists in non-small cell lung cancer(NSCLC).
Materials: For eighteen NSCLC patients the gross tumor volume was delineated manually on CT/PET scans by five independent oncologists and segmented using a CT based automatic tool. Tumor volume and overlap fractions
between the intersection and union of the manual delineations and the autosegmentation tool were compared. All measurements were correlated withthe maximal diameter on macroscopic examination of the surgical specimen.
Results: High overlap fractions were observed between the autosegmentation tool and the intersection (94.52 ± 6.38) and union(91.75±9.16) of the manual delineations. Differences in tumor volume were
not observed between the automatic segmentation (median, 40.3 cm3 ) andmanual delineations (35.89 cm3 ; p = 0.98). The maximal tumor diameter of
the auto-segmented tumor mask correlated strongly with the macroscopic diameter of the primary tumor (correlation coefficient = 0.902). This correlation
was lower for the manual delineations (computing the calculations).

W EDNESDAY, M AY 11, 2011

P OSTERS 191

Fig 1. The body, lungs and gross tumor volume are automatically segmented
on a CT scan (a, left panel); manual delineations are shown for the same
patient (a, right panel). Correlation between the maximum diameter on the CT
auto-segmentation and the macroscopic diameter of the surgical specimen(correlation coefficient = 0.901; b). Volume comparison between the autosegmentation tool and the average of the manual delineations (c).
Conclusions: Tumor volume measurement and 3D definition using a
CT-based auto-segmentation algorithm demonstrated high agreement with
CT/PET manual delineations and showed a high correlation with the macroscopically dimensions on pathology considered the "gold standard". Thismethod may be used routinely in clinical practice and could be employed
as a validated segmentation method for multi-centric clinical trials or highthroughput data mining research.
472 poster
SPATIAL CORRELATION BETWEEN PROSTATE CANCER RECURRENCES AND ORIGINAL DOSE USING NON-RIGID REGISTRATION
A. van de Schoot1 , J. Korporaal1 , M. Moman1 , M. van Vulpen1 , U. van der
Heide1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands
Purpose: In patients with a local recurrence after primary radiotherapy of
prostate cancer, the location of the recurrence compared to the original lesion and the locally delivered dose were studied. Because of deformations(shrinkage), we used non-rigid registration of pre-treatment MRI and CT, and
MRI after recurrent cancer to investigate the location of the recurrence in relation to the location of the primary tumor and the originally delivered dose.
Materials: So far, ten patients with biopsy proven prostate cancer recurrences after primary external beam radiotherapy were included. The prescribed dose was 70 Gy in 1 patient and 77 Gy in all other patients. All patients (age 62-75 year) had a PSA relapse at least 32 months after treatment(period 2004-2006). The MR data set made before treatment contained a T2weighted and a balanced Fast Field Echo image. The MR data set made after
PSA relapse contained a T2-weighted turbo spin echo, a balanced Turbo Field
Echo and a DCE-MR exam. Both examinations were performed on a 3 Tesla
MRI scanner. The registration program Elastix was used to perform registrations between the different data sets from different time points (pre-treatment
MRI and CT and MRI after PSA relapse). The registration accuracy wasquantified by the Dice similarity coefficient of the delineated prostates andthe average absolute distance between the prostate delineations.The original dose distribution and the location of the recurrence were co-registered
to the pre-treatment MR scan. Initial tumor locations were compared withthe location of the recurrences and the planned dose was compared (paired
Wilcoxon signed rank test) with the dose to the tumor and the location of therecurrence.
Results: After registration of the two MR data sets, the overlap of the prostatedelineations had an average Dice score of 0.97 (0.97 0.98). The average median of the absolute distance between the delineations was 0.3 mm (0.3 0.5)
with 90% below 1.0 mm (0.8 1.9). The registration between CT and MR pretreatment data sets had an average Dice score of 0.95 (0.90 - 0.97) and an
average median of the absolute distance between the prostate delineationsof 0.5 mm (0.4 0.9) with 90% below 1.4 mm (1.0 2.1). Nine out of ten patients had a clearly visible recurrence, of which seven overlapped with theinitial tumor location. The average volume, average dose and average D99
of both the initial tumor and recurrence are shown in the table. No significant
differences were found between the average dose of the original tumor andthe dose at the location where the recurrence was later found (p=0.496) andbetween the average D99 of the original tumor and the recurrence (p=0.652).

Conclusions: An accurate registration between the different data sets was
obtained, even when substantial deformation of the prostate had occurred.
We found GTV recurrences in 7 of the 9 patients, with the lowest D99 in arecurring tumor volume of 69.4 Gy.

S 192

P OSTER473 poster
DEFORMABLE IMAGE REGISTRATION OF FDG-PET-POSITIVECONTOURS IN RADIOTHERAPY OF HODGKIN LYMPHOMA
M. Aznar1 , A. K. Berthelsen1 , A. Loft2 , P. M. Petersen1 , L. Specht1
1
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of Radiation
Oncology, Copenhagen, Denmark
2
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of Clinical Physiology Nuclear Medicine, Copenhagen, Denmark
Purpose: Radiotherapy (RT) is a standard treatment component of combinedmodality treatment for early stage Hodgkin Lymphoma (HL). With involvednode RT, all PET-positive lymph nodes on the pre-chemotherapy FDG-PETCT scan must be included in the treatment volume. The volume on the planning CT is then extended to include suspicious nodes as identifiable on prechemotherapy CT. It is difficult and time-consuming for the physicians (radiation oncologists, radiologists and nuclear medicine specialists) to define thepre-chemotherapy PET positive region on the post-chemotherapy treatment
planning CT scan with sufficient accuracy: the scans are difficult to coregisterbecause these images are taken several months apart, the lymphoma has regressed, and the patient position may have changed. Treatment margins areoften added during delineation because of this uncertainty in contour propagation. We hypothesized that deformable image registration (DIR) could be
used as a first step in the propagation of PET positive volumes in order toease the delineation process on the planning CT.
Materials: 10 HL patients were selected for this retrospective study. All patients had pre-chemotherapy PET-CT scans on a flat couch with arms up,
but were furthermore fixated with a dental bite block for the RT planning CTscan. Pre-chemotherapy (PET-CT) and planning (CT) images were fusedboth with rigid and deformable registration in VelocityAI (Velocity Medical
Solutions, USA) and the PET-positive volumes (VPET) were propagated tothe planning CT. The changes in propagated PET positive volumes wererecorded (∆VPET=VPETrigid VPETdeformable). The overlap between VPET
and planning CTV, as defined by the physicians, was analyzed using an Overlap Index (OI= (CTV ) VPET) /VPET) .
Results: The average shrinkage ∆VPET was 109 cm3 (range: 1.6-767). The
OI ranged from 0.38 to 0.92 (mean: 0.63 ± 0.18) with rigid registration andfrom 0.57 to 1.00 (mean: 0.80 ± 0.16) with deformable registration. In all but
one patient, the OI was increased when using deformable registration with anaverage increase of 17% (range: -9 to 38%).
Conclusions: DIR shows potential as a first step of contour propagation,
though the performance of the deformation algorithms in complex situations
with considerable tumour shrinkage requires further investigation. Deforming
pre-chemotherapy PET-CT contours on the planning CT scan appears to bea better starting point than rigid registration and may facilitate the contouring
process for lymphoma patients treated with RT.
474 poster
AUTOMATIC PET-BASED TUMOR CONTOURING: SIGNAL-TOBACKGROUND RATIO VERSUS GRADIENT-BASED CONTOURING
M. Janssen1 , H. Aerts1 , J. A. Lee1 , P. Lambin1
1
MAASTRO CLINIC, U NIVERSITY H OSPITAL M AASTRICHT, UM-GROW,
Maastricht, Netherlands
Purpose: To compare a source-to-background ratio (SBR) based andgradient-based (watershed) PET auto-delineation to the tumor delineations
manually performed by radiation oncologists for patients diagnosed with nonsmall cell lung cancer (NSCLC).
Materials: Nineteen patients diagnosed with NSCLC were included in thisstudy. For all included patients, a FDG-PET-CT scan was performed prior totreatment. Based on the PET-data, two tumor delineations were performed
fully automatic: one delineation was based on standardized-uptake-value(SUV) thresholding with the threshold based on the SBR and one delineation
was based on gradients within the image using a watershed clustering algorithm. Also, the GTVs were manually delineated by 5 radiation oncologists on
fused PET-CT images. The automatic generated PET-based contours werecompared to the tumor contours delineated by the radiation oncologists bydefining two overall tumor contours: the "Union" and the "All Onc Contour"(Fig. 1).
Results: When comparing the contours delineated by the radiation oncologists with the gradient based PET-contour, 90.1±7.1% (range: 75.0 98.8%)of the "All Onc Contour" was present within the gradient based PET-contour,
whereas 99.8±0.5% (range: 98.4 100.0%) of the gradient based PETcontour was present within the "Union" of the contours of the five radiation
oncologists. Comparison of the contours delineated by the radiation oncologists and the SBR based PET-contour resulted in an average overlap of
85.9±10.9% (range: 61.6 97.5%) of the "All Onc Contour" with the SBR
based PET-contour, whereas 88.0±10.1% (range: 66.4 98.1%) of the SBR
based PET-contour was present within the "Union" of the delineations of theradiation oncologists.
Conclusions: The gradient based PET-contour presented with a complete
overlap with the "Union" of the contours of the radiation oncologists, whereas
the contour resulting from SUV-thresholding had an average overlap of onlyW EDNESDAY, M AY 11, 2011
88% with the "Union". Also, over 90% of the region contoured by all radiation oncologists was present in the gradient based PET-contour. Automatic
tumor delineation on PET-images using watershed clustering results in a better agreement with manual delineation by a radiation oncologist compared toautomatic delineation on PET-images based on SUV-thresholding.

W EDNESDAY, M AY 11, 2011

P OSTERS 193

476 poster

477 poster

INTER & INTRA FRACTION BLADDER VOLUME VARIATION FOR
FULL AND EMPTY BLADDER: A COMPARISON
H. M. Dees-Ribbers1 , A. Betgen1 , F. Pos1 , T. Witteveen1 , P. Remeijer1 , M.
van Herk1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiotherapy, Amsterdam, Netherlands

DOSIMETRIC EVALUATION OF MARGIN REDUCTION AND INTRAFRACTION MOTION FOR PROSTATE SBRT
L. Jiang1 , H. Li2 , T. Boike1 , J. Heinzerling1 , T. Solberg1 , R. Foster1
1
U NIVERSITY OF T EXAS S OUTHWESTERN M EDICAL C ENTER, Departmentof Radiation Oncology, Dallas, USA
2
H ENRY F ORD H OSPITAL, Department of Radiation Oncology, Detroit, USA

Purpose: The purpose of this study is to compare inter- and intra-fraction
bladder volume variation during radiotherapy (RT) for bladder cancer with fulland empty bladder. Most bladder motion is caused by bladder and rectum
filling during treatment. At our department we use two different protocols for
bladder cancer RT. For patients with multiple tumors, the clinical target volume(CTV) is the whole bladder, treated empty. Most solitary bladder cancers,
however, are treated with partial bladder RT. These patients are treated witha full bladder to move healthy tissue away from the treatment fields. For whole
bladder RT bony anatomy registration is used, and both inter & intra-fraction
variation affect the precision. For partial bladder RT, markers at the bordersof the tumor are used for image guidance. In that case the precision is mostly
affected by intra-fraction variation.
Materials: We studied bladder volumes of 24 patients with bladder cancer.
For all patients, one planning CT and on average 7 sets (pre & post treatment) of cone beam CTs (CBCTs) were acquired (range 4-14 sets). Eightpatients were treated with an ’empty bladder’ (EB) protocol and sixteen patients with a ’full bladder’ (FB) protocol: they were instructed to empty their
bladder and drink 250 ml water one hour before the planning CT and eachtreatment fraction. The bladder was delineated on all scans by one experienced radiographer. Time trends in bladder volume (V) and volume increase,filling rate (dV/dt) and bladder wall movement were studied.
Results: The statistics of the bladder volume is show in Table 1. The randomvariations in bladder volume are similar for both protocols, The average time
between pre and post irradiation CBCT was 8 minutes. (range 6-18 min) The
average filling rate was 2.1 ml per minute (range 0.02-8.9 ml/minute) which
did not differ between EB and FB. Five of 24 patients (1 EB, 4 FB) had asignificant bladder volume decrease over the whole course of treatment andtwo of them had a decrease in filling rate. The largest intra-fraction bladderwall movement was found in the cranial anterior direction: mean displacement
there was 3.2 mm with a SD of 3.4mm. Intra-fraction wall motion up to 17 mm
was found.

Purpose: The margin added to the prostate (CTV) for Stereotactic Body Radiotherapy (SBRT) is necessary to account for intrafraction motion, but increases the dose to adjacent normal tissues such as the rectum and bladder.
The purpose of this study is to investigate the effect of margin reduction on
CTV and PTV coverage and dose to normal tissues in the presence of intrafraction prostate motion during high dose per fraction radiotherapy.
Materials: Eight prostate cancer patients who received SBRT under an IRBapproved protocol at our institution were selected for this study. Patients weretreated in a stereotactic body frame and a rectal balloon was used for prostate
immobilization. The Calypso Localization System (Calypso Medical Technologies, Inc., Seattle, WA) was used to track the prostate at a rate of 10 Hz
during radiotherapy. Patients were planned with a 2 mm dose grid resolution
using 0, 1, 2, and 3 mm PTV margins (Pinnacle 8.1y, Philips Radiation Oncology Systems, Madison, WI). Patients were treated with an IMRT techniqueusing 13 co-planar beams and a beam energy of 10 MV. The prescription was
10 Gy per fraction to a total of 50 Gy. Only tracking data recorded while thebeam was on was used in the calculation of the probability density functions(PDFs), which describe the probability of displacement of the prostate in the
Lateral (R/L), Vertical (A/P) and Longitudinal (S/I) directions. The planned
static 3D dose distribution was convolved with the PDFs to determine thedelivered dose. The mean planned and delivered dose to the CTV, PTV, anterior rectal wall and bladder were evaluated, along with the volumes of the
CTV and PTV receiving the prescription dose.
Results: Due to the intrafraction motion, the mean delivered dose to the
CTV, PTV and bladder wall was slightly lower than the planned dose. The
prescription dose coverage of the CTV volume was 96.1%, 99.1%, 99.6%,
and 99.9% in the delivered plans for PTV margins 0, 1, 2, and 3 mm, while
the planned coverage was 97.2%, 99.5%, 99.9%, and 100% respectively.
Figure 1A illustrates the difference in CTV and PTV coverage for different
margins with and without motion included. The CTV volume covered by theprescription dose decreased when intrafraction motion was accounted for,but is not clinically significant. The mean delivered dose to the anterior rectal
wall decreased as margins were reduced and increased for all margins whenmotion was included, but only by 1 2% (Figure 1B).

Young scientists ESTRO Poster Session: IGRT
475 poster
ACHIEVING THE PRECISION OF STEREOTACTIC FRAME-BASEDCRANIAL RADIOTHERAPY IN A THERMOPLASTIC SHELL
N. Rosenfelder1 , L. Corsini2 , C. Lamb3 , K. Burke3 , H. McNair4 , M.
Bidmead3 , A. Aitken2 , P. De Ieso2 , V. Khoo1 , M. Brada5
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Clinical Oncology,
London, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Academic Departmentof Radiation Oncology, London, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of Medical
Physics and Radiation Safety, London, United Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Academic Departmentof Radiation Oncology, Sutton, United Kingdom
5
T HE I NSTITUTE OF C ANCER R ESEARCH AND T HE R OYAL M ARSDEN NHSF OUNDATION T RUST, Clinical Oncology, Sutton, United Kingdom
Purpose: The relocation accuracy of the Gill-Thomas-Cosman frame forstereotactic cranial radiotherapy is <2mm. Patients unable to tolerate theframe can be immobilised in a thermoplastic shell but relocation is less precise and larger margins are applied to create the planning target volume. The
ExacTrac (ET) imaging system allows fast, accurate verification with low radiation dose. This study compares the setup errors and the required setup margin (SM) for patients in a shell with daily online correction with those achievedfor patients in a frame using the standard correction protocol using ET imaging.
Materials: 15 patients underwent treatment in a shell (daily imaging and correction) and 15 in a frame (standard imaging and correction days 1-3, thenweekly). A total of 1919 kV images were obtained; 1916 (99.8%) were available for review, corresponding to 363 sets of pre- and post-correction image
pairs from shell patients (18-29 pre/post-correction pairs/patient), and 116
sets from frame patients (6-12 pre/post-correction pairs/patient). Population
systematic () errors and random (σ ) errors pre- and post-correction were
calculated for each group. The effect of setting theoretical tolerances of 1, 2oand 3 mm/ was assessed. For each tolerance, if all translational/rotational
initial setup errors were within tolerance, initial errors were copied to postcorrection errors, as
if shifts had not been applied. SM was calculated using+0.7σ described by van Herk et al.
the formula SM=2.5
Results: Systematic and random Errors (vert/long/lat/yaw/roll/pitch) and SM(anterior-posterior/superior-inferior/left-right) are shown in the table.

Conclusions: Using a daily online correction protocol, the relocation accuracy of the frame can be achieved in patients immobilised in a shell.
error such as intrafraction motion, delineation, and imOther sources ofager/linac coincidence errorsmust be considered before margin reduction, but
if acceptable, larger margins may not be necessary for shell-based treatment.
Furthermore, frames may become unnecessary.

Conclusions: Intra-fraction volume variation is small compared to interfraction variation. However, it should be taken into account, especially for
cranial-anterior located tumors. Bladder filling rate was not different in the
EB and FB group. Contrary to common believe, both empty and full bladder
protocols have similar inter-and intra-fraction uncertainties.

Conclusions: This study demonstrates that the dosimetric impact of intrafraction motion during prostate SBRT delivery is not clinically significant
when a rectal balloon is combined with Calypso for assessment of intrafraction motion. Reducing PTV margins can spare more of the anterior rectumS 194

P OSTER

without significantly decreasing CTV coverage. Reducing the dose to the rectum may decrease the severity of early bowel toxicity experienced by thesepatients or allow higher doses if 50 Gy proves to be ineffective.

W EDNESDAY, M AY 11, 2011
478 poster
COMPARISON OF MVCT AND OPTICAL SURFACE SYSTEMS FORPATIENT POSITIONING
G. Guidi1 , E. Luppi2 , E. Cenacchi1 , F. Falciola2 , C. Piani2 , F. Bertoni2 , T.
Costi1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Medical Physics, Modena,
Italy
2
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Radiation Oncology,
Modena, Italy

1

Purpose: The aim of the job is to compare, for several anatomical districts,
the results of the setup and repositioning errors using a MVCT and an opticalsurface system installed at the LINAC. The final goal is to verify, if the MVCTand the optical system can provide a common error setup independently by
the machine and analyze the opportunity to use the optical system instead thedaily MVCT (or CBCT) using a common protocols of setup and immobilization
devices and maintaining the same accuracy level.
Materials: 42 patients (21 Pelvi&Prostate, 12 Thorax, 10 Brain) are been coregistered using the Tomotherpy MVCT and 35 patients (14 Brain, 11 Thorax, 10 Pelvis&Prostate) are co-registered using an optical surface system(VisionRT). The co-registration is done with the kVCT data, using a mutual
information algorithm. A total of 965 MVCT and 954 Optical Surface shifts
are been recorded. For X,Y,Z directions are been calculated the weighted
average shifts, the magnitude and the 95% of confidence. The work include
an ANOVA analysis to compare the correlation of the measures done using
the system independently and in correlation for the same pathologies.
Results: The results reported in table show the mean shift and the magnitudeof the setup error with both the systems.

W EDNESDAY, M AY 11, 2011

Conclusions: As evident from the data and by the ANOVA analysis, usingsame type of immobilization and repositioning techniques, the co-registration
applied with the MVCT or using Optical surface system can permit to control
the setup error of the patients with very small adjustment. The measures
are consistent using the same system and its have a excellent reproducibility independently by the pathology. Unfortunately the systems have showed
different level accuracy compared to each other. VisionRT can produce verysmall adjustment, but the same resolution is not confirmed by the MVCT forthe same pathologies and for pelvis and thorax region could be highly inadequate. The only use of the optical system could be dangerous for repositioning purpose of the internal anatomy, but could be a excellent tool toguarantees a faster setup and a continuous check for each fraction, if a daily
MVCT or CBCT is not performed before the treatment fraction or during thetreatment. These benefits could increase the quality of treatment without increasing the treatment time.
479 poster
EVALUATION OF VISABILITY OF BOTH LOW AND HIGH DENSITYFIDUCIAL MARKERS ON MR, CT, CBCT AN KV IMAGES
B. Holch Kristensen1 , R. H. Hansen2 , J. Sjöberg1 , D. Sjöström1
1
2

H ERLEV H OSPITAL, Radiation Therapy, Herlev, Denmark
H ERLEV H OSPITAL, Radiology Department, Herlev, Denmark

Purpose: Fiducial markers are now commonly used for prostate positioning. The markers used are traditionally made of high density material (gold)
to be able to identify them when a MV beam is used. The drawback withgold markers is that they are not visible in T2-weighted MRI images used todelineate prostate and also give rise to prominent star artefacts in the CT
images. The best marker would give rise to smaller artefacts in CT and an

S 195

adequate susceptibility artefact in MRI which makes the marker visible but
not to an extend so the image quality is degraded or the geometrical uncertainty increases. Since modern accelerators are equipped with kV imaging
other materials compatible with both MRI and CT are of great interest. The
purpose of this study is to find a suitable marker material when using CT and
MRI for treatment planning and kV imaging for setup.
Materials: Five different commercially available markers of different material
composition, 24 carat gold, 18 carat gold/copper, 24 carat gold/iron core,gold/nitinol and carbon/zirconium, were implanted into a meat phantom. The
phantom was imaged using clinical routine imaging parameters in both CT
and MRI scanner to identify the visibility of the different markers and if thegeometrical position of the marker was correct. MV and kV on-board imaging
systems capable of performing CBCT were also used to test the visibility ofthe markers at the linear accelerator. The best suitable marker was implanted
into four volunteer patients in order to study the contrast properties in vivo with
anatomical structures present.
Results: The gold/nitinol marker material composition was found to be optimal for both MRI and CT applications with significantly reduced star artefacts
in the CT images and enhanced visibility in the T2-weighted MRI images withsmall geometrical distortion. However, due to the relatively low attenuation
properties it is not possible to identify the markers with MV imaging. Furthermore, it is essential to use proper exposure parameters and a proper fieldsize for the patient positioning with kV planar imaging.
Conclusions: A marker optimal for MV imaging is not preferable for CT and
MRI imaging. When having kV modality for patient setup other material composition can be used. In this study a marker material composition suitable formultimodality imaging has been found.
480 poster
QUANTIFICATION OF MR IMAGE SUSCEPTIBILITY DISTORTIONSFOR IGRT
T. Stanescu1 , K. Wachowicz2 , D. Jaffray1
1
P RINCESS M ARGARET H OSPITAL, Department of Radiation Physics,
Toronto, Canada
2
C ROSS C ANCER I NSTITUTE, Department of Medical Physics, Edmonton,
CanadaThe results reported in the ANOVA table show the agreement between themean shift obtained using the same system independently by the pathology
and the results of the hypothesis that the systems cannot replace each otherfor a specific pathology.

P OSTER

Purpose: To quantify the magnitude of magnetic resonance (MR) image susceptibility distortions in the context of radiation treatment (RT) planning andpatient setup verification.
Materials: Susceptibility-related image artifacts are produced at the interfaces between materials with significantly different susceptibility values (e.g.,
air-tissue interface). This effect is due to variations in the local magnetic field
induced by the intrinsic properties of the materials. To quantify the susceptibility distortions we used a method consisting of the following steps a) patient
CT data is segmented into susceptibility relevant anatomical volumes (softtissue, bone, lung/air), b) 3D susceptibility masks are generated by assigning bulk susceptibility values to structures from a), c) numerical simulationsof the magnetic field are performed using finite difference methods, and d)
the simulated magnetic field distributions are converted into distortion maps.
CT images were preferred over MR images in order to isolate the effect ofsusceptibility from other spurious artifacts. The numerical simulation engine
was extensively validated using phantom data and against analytical solutions. The distortion fields can be used for evaluating treatment plans (turning on/off the distortions) and requirements for patient setup verification (e.g.,
MR-CBCT, MR-MR).
Results: The susceptibility distortions were investigated for several cancer
sites, i.e. brain, lung, prostate, head & neck. The simulations were performed
for main magnetic fields (B0) ranging from 0.2 to 3.0 T, and readout gradientstrengths of 2 to 20 mT/m. The magnitude of distortion increases with thedecrease of both B0 and the readout gradient. The artifacts also depend on
the anatomical volumes’ shape and their relative orientation to the appliedfield. The susceptibility distortion plots can be generated as a function of B0
and the readout gradient. These can be used to optimize the MR scanning
protocols for the acquisition of patient data required in the RT planning andverification processes. RT plans were evaluated to quantify the impact of susceptibility distortions. At low magnetic fields the plan accuracy is not altered
due to a reduced level of distortions (within image resolution). In contrast, at
higher fields and/or low gradient strengths the quality of the plans decreased
significantly, leading to poor target dose coverage and increased dose to adjacent critical structures.

Conclusions: The susceptibility distortions were determined via numericalsimulations for a wide range of cancer sites. The impact of these distortions
was quantified in the context of RT planning simulation and patient setup verification. Depending on the MR imaging protocol (i.e., B0 and the direction
and strength of the readout gradient) the patient images may need to be corrected for susceptibility distortions to achieve desired spatial accuracy.
481 poster
SHARED GUIDELINES FOR THE TREATMENT PLANNING OF
NEO-ADIUVANT RT BY 3D CONFORMAL AND VMAT TECHNIQUES:CONTOURING INTER-VARIABILITY AND DOSIMETRIC CONSEQUENCES.
F. Lobefalo1 , M. Bignardi1 , G. Reggiori1 , S. Castiglioni1 , E. Infusino1 , A.
Tozzi1 , A. Fogliata2 , P. Navarria1 , P. Mancosu1 , M. Scorsetti1
1
I STITUTO C LINICO H UMANITAS, Department of Radiation Oncology,
Rozzano (Milan), Italy
2
O NCOLOGY I NSTITUTE OF S OUTHERN S WITZERLAND, Medical Physics
Unit, Bellinzona, Switzerland
Purpose: To evaluate whether the introduction of shared guidelines could
reduce the inter-variability contouring in the neo-adjuvant rectum cancer definition and to assess the dosimetric uncertainty for 3D-conformal RT (3D-CRT)and volumetric modulated arc therapy by RapidArc (RA) techniques.
Materials: Ten patients with rectum cancer subjected to neo-adjuvant RT
were randomly selected from the internal database. Four radiation oncologists were asked to contour the clinical target volume (CTV) in blind mode.
After that, shared guidelines were introduced to give general criteria for thecontouring of rectum target. After at least one month, the four radiation oncologists defined the CTV following the guidelines. For each patient six intervolume intersections (I) and unions (U) were calculated coupling the contoursof the various oncologists. This was repeated for the contours drawn after theguidelines. Agreement Index (AI=I/U) was calculated pre and post guidelines.
For each of 80 contoured targets, two RT plans (3D-CRT using 3-4 fields andRA using single modulated arc) were optimized. All the plans were optimized
on one oncologist’s PTV (PTVi) and, for the remaining oncologist’s contours(CTVj,k and z), the CTV volume receiving at least 95% of the prescribed dose
(CTV V95%) was calculated and used as a parameter.
Results: The inter-operator AI pre guidelines was 0.60 and was increased
up to 0.72 post guidelines. The mean volume difference between the various
CTV couples passed from 200±75 cm3 to 75±45 cm3 after the introductionof guidelines. The mean percentage CTV volume receiving 95% of the prescribed dose was 93.6% before and 96.7% after the introduction of guidelines
for the 3D-CRT, for RapidArc the increase was more relevant, passing from
86.5% (pre) to 95.0% (post). For organs at risk (OAR) the results were thefollowing: V40Gy for bladder in 3D-CRT were ~40% and ~26% respectively
before and after guidelines, while the mean dose to the femurs resulted 31.5
Gy (pre) and 29.5 Gy (post); with RapidArc V40Gy for bladder passed from
~26% to ~12% before and after guidelines, while the mean dose to the femurs
remained the same.
Conclusions: The introduction of guidelines reduces considerably the intervariability in neo-adjuvant rectum cancer CTV definition and assures a greater
OAR sparing (better for RA than 3D_CRT); this is because CTV mean volumes are smaller probably due to the higher confidence in contouring thatavoids exceedingly conservative contours. This appears particularly relevant
for RA technique where CTV V95% increases of 8.5%. in conclusion, while
for 3D-CRT techniques guidelines may be useful, this work reveals their essential role for modulated techniques.

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P OSTER

Young scientists ESTRO Poster Session: Radiation technologists

W EDNESDAY, M AY 11, 2011
corrections are applied. The consequence of the setup errors on HFS and
HFP treatment plans will be presented.

482 poster
TREATMENT DELIVERY FOR FRAMELESS INTRA-CRANIALSTEREOTACTIC PATIENTS: A FASTER AND MORE ACCURATE
APPROACH
A. Kuijpers1 , S. Lang1 , A. Walker1 , J. Hrbacek1 , C. Linsenmeier1 , O.

W EDNESDAY, M AY 11, 2011
MV, 10 MV and 15 MV. Ge-doped optical fibres having the same individual
sensitivity were retained in groups of fifteen to be loaded into black plastic
capsules. A total of 42 capsules of Ge-doped optical fibres were madeready and measurements were performed under the following conditions:
6 MV energy, 2 Gy dose, 10 cm x 10 cm field size, and 100 cm-nominal
source-to-surface distance (SSD), use being made of three Varian linear
accelerators. In order to calculate absorbed dose to water, Dw the following
equation was used, based on the IAEA TLD audit system of Izweska et al(2007):

Riesterer1 , C. Winter1
1
U NIVERSITY H OSPITAL Z ÜRICH, Zurich, Switzerland

Dw = M N fSi fhol ff ad flin fengy fdose rate ftem fang
Purpose: Since May 2010, twenty intra-cranial stereotactic patients havebeen treated with the Varian TrueBeam STx. This new platform of linear
accelerators should allow easier, faster and more accurate patient set up
and treatment delivery. We therefore performed time and accuracy studies
to evaluate potential advantages of the TrueBeam.
Materials: All twenty patients were immobilized using a BrainLAB mask system. Patients were treated either using a VMAT or an IMRT technique. For
at least five fractions, image guidance was performed with a kV image pairfollowed by a CBCT. All positioning discrepancies were documented including pitch and roll. Translational and rotation errors were corrected daily. A
post treatment CBCT was acquired to analyze intra-fractional patient stability.
For each fraction the time needed for preparation, imaging and treatment wascollected using a MatLab program.
Results: Intra-fractional motion was found to be below 1.1mm for all patientsfor all treatments. The mean shift was 0.56 mm (2SD= 0.54 mm). Shifts during treatment in longitudinal and lateral direction were non-systematic, however we observed a systematic shift of -0.5 mm (2SD= 0.4 mm) in verticaldirection, which is likely related to the sagging of the patient in the mask.
Both pitch and roll were non-systematic and below 1.5◦ . Differences of up to
3 mm were observed between 2D-2D matching and 3D-3D matching. However when the cranial border of the skull was included on the 2D-2D matching
better agreement was seen. Treatment delivery was reduced from 11 min on
our former linac to 6.6 min for an IMRT plan and 2.99 min for Rapid Arc delivery.
Conclusions: Less deviation was found between 2D-2D matching and 3D3D matching when the cranial border of the skull was included in the initial
kV paired images. The minimal intra-fractional errors will enable us to further implement a non-invasive Radiosurgery program. The advanced clinicalfeatures of the Truebeam allowed us to significantly reduce our treatment delivery time.
483 poster
POSITIONING IN BREAST RADIOTHERAPY; SMALLER SETUPERRORS IN SUPINE COMPARED TO PRONE POSITIONING
H. Jonker1 , W. Jansen2 , M. Jonker2 , A. Scholten2 , C. Marijnen2
1
L EIDEN U NIVERSITY M EDICAL C ENTER, Clinical Oncology, Leiden,
Netherlands
2
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Leiden, Netherlands
Purpose: In radiotherapy a stable and reproducible treatment position allowing an efficient treatment plan for the desired target volume is instrumental. In
view of this, the reproducibility of the two most widely used positions in breast
cancer treatments were tested: head first supine (HFS) and head first prone(HFP).
Materials: Thirty-one breast cancer patients got multiple CT-scans in both
HFS and HFP position. In HFS patients were immobilized on an angled
breast board with their ipsilateral arm abducted and externally rotated. A
prone breast board (ClearVueTM Prone Position Breast Radiotherapy System) was used for HFP positioning. Patients were scanned in both HFS and
HFP position on day 1 and again 3-4 days thereafter. To simulate actual
treatment setup, fiducial markers at the isocenter were used to realign thepatient.CTV’s were outlined by a single radiation oncologist. Volume matches
between the first and second scan in each position were made with fusion
in Pinnacle3 v8.0m. From this, data on rotation and translation could be extracted in X, Y and Z axes for each treatment position. The translation vector
was calculated as the square root of X2 , Y2 and Z2 . Because the first andsecond scans were acquired on the same equipment, setup error can be interpreted as mainly random.
Results: The average volume of the CTV was 780 cc for HFS and 870 cc for
HFP respectively, but showed large individual differences (range 143-1992
cc for HFS and 143-2200 cc for HFP). Comparison on an individual baseshowed an average discrepancy of 11.5% (range <1-33%) between HFS and
HFP. There was no significant difference in the rotation error between HFS
and HFP (< 0.5). The average translations in X, Y, and Z direction were 3.9mm, 4.1 mm and 5.5 mm for HFS and 4.6 mm, 3.6 mm and 6.7 mm for HFP,
respectively. The average translation for HFP is 1 mm larger than for HFS in
all directions (corresponding vector = 1.7mm). No correlation between CTV
volume and required translation or rotation could be demonstrated. Figure 1
shows the translation vectors required for a match for each patient, orderedby magnitude. From this figure, it can be concluded that in HFS and HFP
a vector of 1 cm is only sufficient for 50% of the patients if no further setup

where M is the mean readings of the 15 Ge-doped optical fibres in a capsule,
N is an average calibration coefficient of the Ge-doped optical fibres in thecapsule and the factors fsi fhol ffad flin fengy fdose rate ftem f ang correct forindividual characteristics: the Ge-doped optical fibres holder, fading, linearity,
energy, dose-rate, temperature and angular-dependence. The averagecalibration coefficient of the Ge-doped optical fibres, N was determinedaccording the equation:

N =Conclusions: In breast cancer patients, repeated CT-scans show equivalentrotation errors in HFS and HFP. However, translation vectors are smaller in
HFS than in HFP. Hence, HFS has a smaller initial setup error than HFP. Bothfor HFS and HFP the setup error is shown to be independent of the breast
volume. This indicates that CTV-PTV margins do not require adjustment withsmaller or larger breast size.
484 poster
AN INVESTIGATION OF THE SUITABILITY OF GE-DOPED OPTICALFIBRES IN MAILED THERMOLUMINESCENCE DOSIMETRY AUDITS
OF RADIOTHERAPY DOSE DELIVERY
N. Mohd Noor1 , D. Bradley1 , A. Nisbet1 2
1
U NIVERSITY OF S URREY, Department of Physics, Guildford, United
Kingdom
2
T HE R OYAL S URREY C OUNTY H OSPITAL NHS F OUNDATION T RUST,
Department of Medical Physics, Guildford, United Kingdom
Purpose: The need for accuracy in radiotherapy is well established. One
tool for ensuring consistency in dosimetry is the use of the intercomparison audit. This may range from use of lithium fluoride thermoluminescence
dosimeter (TLD) audits, as organised by the IAEA, or on-site visits using ionisation chambers and appropriate phantoms. The complexity of parameters
audited may cover basic reference dosimetry through to in vivo dosimetryor advanced radiotherapy techniques. The aim of the present investigation,using high energy photon beams, is to undertake a pilot audit aimed at establishing the potential of a mailed commercial Ge-doped optical fibre TLD
system in measuring beam output under reference conditions. Prior to theaudit, the Ge-doped fibres have first been screened to establish dosimetriccharacteristics of such TL media, including reproducibility, linearity, fading,energy-, dose rate-, angular-, and temperature-dependence. Fibres with suitable dosimetric characteristics were retained in groups of fifteen and loaded
into plastic capsules for use in this pilot audit. The pilot audit irradiation was
carried out using three different linear accelerators located in one UK radiotherapy centre. A total of 42 capsules of selected Ge-optical fibres were irradiated to an absorbed dose to water of 2 Gy using a purpose built holder,
based on the IAEA TLD holder design, in a Qados water tank. In order to calculate absorbed dose to water the equation proposed by Izweska et al (2007)
in the IAEA TLD audit system was applied. Subsequent to these irradiationsa mailed audit of all Malaysian radiotherapy centres is ongoing.
Materials: The silica-glass optical fibres used are single-mode INOCORP(Canada) Ge-doped optical fibres, core diameter 9 µm and cladding
diameter 116 ± 0.1 µm. This medium has been determined to form aneffective TL dosimeter, offering features such as good spatial resolution,high sensitivity, cost-effectiveness, small size and minimal fading. Prior to
the audit excercise, a large collection of Ge-doped fibres were screened toestablish individual performance using an ionisation chamber placed at thesame depth as the TL-detector in a perspex phantom. Only fibres providinga response within ±5% of the batch mean and reproducibility of better than
5% were used in this audit. The fibres were also characterised for theirindividual sensitivity factor, linearity with dose, fading, dose-rate, energy,
temperature and angular dependence to ensure the tightest possible control
of influencing factors using nominal megavoltage energy photon beams of 6DiMi − B

where Di and Mi are the dose given (determined by using the IPSM 1990
Code of Practice) and the mean reading of the 15 optical fibres in each
capsule respectively, B is the average background reading. The value ofindividual Ge-doped optical correction factor, Si was determined through therelation of Claudio Furetta (2003).

Si =



ref

M net
Mi − Moi

where M ref net average of the reference dosimeters, Mi is the reading of theith dosimeter annealed and irradiated at a well defined dose D, and Moi is the
background reading of the same dosimeter after annealing but not irradiated.
The IAEA holder correction factor, fhol as measured by Izweska et al (1996)
was used to determine the absorbed dose value since the Ge-doped holder
was based on the design of the IAEA TLD holder.A Solaro TLD reader (Vinten
TLD, Reading, UK) provided for Ge-doped optical fibres readout, care being
made to use a nitrogen gas atmosphere of 0.5 bar. Nitrogen gas was used
to suppress spurious light signals from triboluminescence and also to reduce
the oxidation of the heating element. Triboluminescence is a potential issue incutting fibres into 6 mm long pieces. During readout the following parameters
were used: preheating the temperature of 160◦ C for 10 seconds; readout
temperature of 300◦ C for 25 seconds with a heating cycle ramp rate of 25◦ C
per second. An annealing temperature of 300◦ C was used for 10 seconds toremove any residual signal in the fibres.
Results: The dosimetric characteristic investigation results showed the Gedoped optical fibres have reproducibility within ±5% after five repeated measurements and linear response for all megavoltage photons beam energies
for doses from 5cGy up to 1000 cGy. The fibres were also found to be dose
rate-, angular- and temperature-independent. However, a small energy dependent response was found in the range 3 to 5% for all megavoltage photons beam energies used. Concerning the effect of environmental temperature on the fibre, the results showed minimal fading of 26 % at 180 days
post-irradiation when held at room temperature but a 12 % decrease of TL
yield when stored at 35o C for 10 days post-irradiation. For the preliminary
pilot audit in the UK, corrections for dose rate, angular and temperature effectand energy dependence in the absorbed dose to water calculation were unity.
Corrections for fading and dose linearity were also close to unity since there
was no delay between irradiation and the readout time for the Ge-optical fibres. In addition, the fibres response was also found to be linear with dosein the dose range used in this pilot audit. From an original 42 Ge-doped
capsules, a total of 27 capsules were observed to provide good agreementwith the stated dose. Capsules with values outside of the range of acceptablereadings were discarded and a new set batch of Ge-doped capsules were obtained with optimum uniformity in the TL response and these are now readyto use as mailed dosimeters in the current dose intercomparision exercise of
Malaysian radiotherapy centres.
Conclusions: 9 µm diameter core Ge-doped fibres represent a viable system for use in mailed audit radiotherapy programmes due to its small physical size, flexibility, modest cost and radiation response characteristics. The
current stage in this study is to mail out the selected Ge-doped batch to eight
Malaysian radiotherapy centres who have agreed to participate in a dosimetry
audit based on the pilot audit results in the UK. To standardize the irradiation
procedure, optical fibres (both irradiation samples and controls), radiotherapy centre detail sheet, technical instruction sheets and a dose data reportsheet will be sent to each radiotherapy centre. Using the returned fibres andcompleted data, TL reading from the mailed optical fibres will be analysed

P OSTER

S 197

and from this a report of the variation from the standard 2 Gy dose will be
constructed, in terms of the measured/expected dose ratio against the confidential identification code for each centre. References:
1. Furetta, C., (2003). "Handbook of Thermoluminescence", World Scientific Publishing Co.Pte.Ltd.
2. Izewska, J., Novotny J., Dutreix A., Van Dam J., van der Schueren E.,(1996).The influence of IAEA standard holder on dose evaluated fromTLD samples. Physics Medicine Biology 41, 1-9.
3. Izewska, J., Georg, D., Bera, P., Thwaites, D., Arib, M., Saravi, M.,
Sergieva, K., Li, K., Yip, F. G., Mahant, A. K., Bulski, W., (2007).A
methodology for TLD postal dosimetry audit of high-energy radiotherapy photon beams in non-reference conditions. Radiotherapy and Oncology 84, 67-74.

485 poster
RESIDUAL LYMPH NODE SET-UP ERRORS IN PROSTATE/PELVICSIB TREATMENT USING FIDUCIAL MARKER BASED SETUP
E. H. Thøgersen1 , A. Vestergaard1 , M. Høyer2 , L. P. Muren1 , J. B.
Petersen1 , L. Bentzen2
1
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
Purpose: Patients with locally advanced prostate cancer can be treated withradiotherapy (RT) to the prostate (CTV-p) and pelvic lymph nodes (CTV-ln)
using a simultaneous integrated boost (SIB) IMRT technique. In this setting,positioning based on orthogonal kV images matched on implanted prostatefiducials is an option. However, the CTV-p and CTV-ln are likely to have independent motion patterns. The aim of this study was to calculate translationaland rotational errors of the CTV-ln using fiducial marker based IGRT.
Materials: The study included ten patients treated with a SIB IMRT techniqueand with daily 2D kV image registration based on fiducials. Cone-beam CT
scans (CBCTs) in treatment position were acquired after treatment fractiondelivery approximately once a week, giving a total of 68 CBCTs. For the purpose of this study, the CBCTs were rigidly registered to the planning CT (pCT)in the Eclipse planning system (ver. 10.0, Varian Medical Systems) using thefiducials but without rotational correction. As the CTV-ln was assumed to bein fixed position to the pelvic bones, a rigid bone match from the CBCTs topCT was performed to quantify the translational errors of the CTV-ln relative
to the fiducials. The systematic and random setup errors were calculated.
Rotational errors were determined using the same approach, except that thematches now accounted for both translations and rotations.
Results: The systematic (Σ) and random (σ ) setup errors of the lateral (LR),anterior/posterior (AP) and cranial/caudal (CC) errors as well as the pitch,rotation and roll are summarised in figure. For LR and CC translational errors the random errors were larger than the systematic errors while in the
AP direction, the systematic error was larger than the random error. Two patients showed large systematic errors and visual inspection revealed a large
distension of the rectum on the pCT compared to all subsequent CBCTs. Exclusion of these two patients halved the systematic error in the AP direction.
Rotational errors were limited and comparable to published data.

S 198P OSTER

Conclusions: The translational errors quantified in this study suggest thatan IMRT-delivered SIB technique for the prostate and pelvic lymph nodes
using daily fiducial marker based set-up can be accurately performed using
adequate PTV margins. The study emphasises the importance of controllingrectal filling in both the planning and delivery stage of RT.
486 poster
DEVELOPMENT OF A NOVEL TREATMENT PLANNING MODULEFOR CREDENTIALING ROTATIONAL IMRT TECHNIQUES IN THE UK
Y. M. Tsang1 , E. Aird1 , L. Ciurlionis1 , C. Clark2 , E. Miles1 , K. Venables1
1

M OUNT V ERNON H OSPITAL, Northwood Middlesex, United Kingdom
2
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, Guildford,
United Kingdom
Purpose: The increasing use of tomotherapy and volumetric modulated arc
therapy in UK centres will result in more centres choosing to use this technology in a clinical trials setting. The NCRI Radiotherapy Trials QA group(RTTQA) have developed a new module to integrate into their IMRT credentialing programme to cover rotational IMRT delivery.
Materials: Based on the original treatment planning system tests (TPS) in the
IMRT credentialing programme, a 3DTPS test was designed specifically for
rotational IMRT techniques. This was sent out to 7 experienced UK centres
to plan, with the recommendation that the planning time was similar to thattaken to produce a complex clinical IMRT plan.
Results: The study included 3 RapidArc, 2 VMAT and 2 helical tomotherapy plans. Initially, centres tried to optimise plans following guidelines in the
ICRU reports 50 and 62 to achieve the dose homogeneity criteria of -5% to+7% for each of the PTVs whilst minimising dose to the remaining volume atrisk (RVR) as far as possible. This proved to be very difficult due to the stepchange in relative prescription doses of abutting PTVs. The task was thenredesigned with three planning goals and the relevant priorities which weredeveloped from the concepts from AAPM TG119 and ICRU 83 reports. Centres were asked to re-optimise plans and to perform their own in-house QA toensure that plans were deliverable within clinical tolerance. All plans fulfilled
the primary goal. The table attached showed that tomotherapy and RapidArc plans achieved the remaining goals while VMAT plans struggled. The
common QA tolerance level chosen was gamma 3%3mm with a pass-rate of95%.

Conclusions: The extra planning module for rotational therapy techniques
has been developed and validated for the RTTQA IMRT credentialing programme. This will form one of the components included in the Pilot Rotational
Radiotherapy Audit planned for early 2011 by the Institute of Physics andEngineering in Medicine and the National Physical Laboratory.
487 poster
DOSIMETRIC COMPARISON OF LUNG CANCER RADIOTHERAPYIN ALL RESPIRATORY PHASES AND IN ONE PHASE USING 4DCT
R. Kulik1 , D. Gabrys2 , K. Trela2 , K. Slosarek1
1
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , Department of Radiotherapy Planning,Gliwice, Poland
2
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , Department of Radiotherapy, Gliwice,
PolandPurpose: Four-dimensional computerized tomography scans (4DCT) as well
as gated radiotherapy are used in treatment of tumors’ located in lung. With
4DCT we are able to delineate target volume on all respiratory phases andradiation is delivered during free breathing cycle. We could also delineate
our target on the basis of one respiratory phase and deliver gated treatment
choosing specific phase for irradiation. Up to now littlie is know about comparison of both techniques in terms of target and normal tissue dose distribution.
Materials: In the present paper we analyzed data of 30 patients treated forprimary or metastatic lung tumour. We chose only tumours which were clearly
separated from the lung tissue. We used 4DCT to characterize tumor motion
and create treatment volumes. For all patients we delineated two GTV, one
based on all 10 respiratory phases (GTV 4D) and based on one phase (GTV
GAT). To create CTV’s we added the same 0,8 mm to GTVs and further 0.3
mm for PTVs. Two treatment plans were performed (4D and GAT) and dosevolume distributions were analyzed in respect to target and normal tissue.

W EDNESDAY, M AY 11, 2011
Results: Various tumour motions was included, motion along the superiorinferior direction was greatest mean 0.9 cm (0.3-2). GTVs volumes weresignificantly bigger in 4D than in GAT, mean 8.8 vs 4.9 cm3, also CTV 41.4 vs28.3, and PTV 63.8 vs 24.7 were bigger (p<0.01). We achieved similar dose
distribution in PTV4D mean 100.7% ± SD 0.7 and minimum 94.6% ± 0.9 for4D plan, and PTVGAT for GAT plan mean 100.4% ± 0.8 and minimum 95.1%± 0.9, but when we look at the dose distribution in PTV4D in the plan GATplan, we found decrease in minimum dose to 66.5% (3.6-95.5), and mean
97.8% ± 2.9, what is explain by differences in target volumes. Radiotherapy
delivered using GAT gave lower lung doses than using 4D with reduction ofmean volume receiving 5 Gy by 2.2% (0.1-5.9), V10 Gy 4.4% (0-11), V20 Gy
4% (0-10.7). and reduction of mean heart volume receiving 5 Gy by 3.6%
(0-10.3), V10 Gy 1.1% (0-7.4). Also volumes of spinal cord were lower withGAT than 4D. We also found a strong correlation between reduction in lungand heart parameters and GTV motion.
Conclusions: Using gated radiotherapy we are able to decrease GTV, CTV
and PTV volumes in comparison to volumes delineated on all respiratory
phases. Decreased target volumes are responsible for improvement in dose
distribution in normal tissue especially in the lung and heart.

W EDNESDAY, M AY 11, 2011

P RESIDENTIAL SYMPOSIUM

S 199

Conference lecture

Presidential symposium

Honorary Members Award Lectures

ESTRO-ESMO-ESSO-ECCO Presidential symposium: Clinical Oncology: The future of Radiotherapy, Medical Oncology and Surgical Oncology

488 speaker
THE BEST OF TWO WORLDS
A. Chiti1
1
IRCCS H UMANITAS, Nuclear Medicine, Rozzano - Milano, Italy
Purpose: The increasing use of molecular imaging in radiation treatment
planning is reshaping the way of thinking of both radiation oncologists andnuclear medicine physicians. This contribution is aimed at looking what has
been done, what is on the way and what can be forecasted in the future.
Methods: Great efforts are on their way to have a better integration of two
worlds: radiation oncology and nuclear medicine. These efforts are not only
on the technical and methodological side but, most of all, on the professional
collaboration and integration.
Results: The fruitful cooperation between ESTRO and EANM is leading the
integration of the best molecular approaches to cancer detection and characterization within the best treatment procedures in radiation oncology.
Conclusions: The future is going to be one of a deeper integration between
molecular imaging and radiation oncology.
489 speaker
HEAD NECK CANCER: PROMISES, PITFALLS, CHALLENGES &OPPORTUNITIESJ. P. Agarwal1
1

TATA M EMORIAL H OSPITAL, Radiation Oncology, Mumbai, India

Head-neck cancer is the commonest cancer in developing countries including India where it constitutes over a quarter of the overall cancer burden.
Early stage disease is treated equally well with either surgery or radiotherapy. Advanced stage disease mandates the use of combined modality treatment. Traditionally, surgery followed by post-operative radiotherapy has beenused for improving outcomes. Recent evidence supports the use of adjuvant
chemo-radiotherapy in high-risk resected squamous cell carcinoma. The current emphasis on organ and function preservation has made definitive radiotherapy with concurrent systemic chemotherapy the contemporary standardof care in the non-surgical management of loco-regionally advanced headneck cancer. There has been renewed interest in Induction chemotherapy
followed by loco-regional therapy both as part of an organ-preservation protocol as well as improving resectability in borderline tumors. With deeper
insights and mature understanding of molecular biology of head-neck cancer,
EGFR-directed therapy is being widely integrated into the therapeutic armamentarium.
Progress in head-neck cancer can be largely attributed to meaningful biological, translational, and clinical research conducted worldwide over the lasttwo decades resulting in shifting paradigms and changing clinical practice. In
keeping with the times, we at the Tata Memorial Centre have evolved from
simple two-dimensional techniques to high-precision conformal radiotherapy(3D-CRT, IMRT, IGRT). There has been a concerted effort to generate quality
evidence from within our own population by hypothesizing and answering clinical questions through simple relevant trials, both at the institutional, national,
and international level. The presentation will discuss progress in head-neckcancer and describe our evolution over the years.

490 speaker
CLINICAL ONCOLOGY: THE FUTURE OF RADIOTHERAPY AND
MEDICAL ONCOLOGY, LANCET APRIL 18, 1981. STATUS THEN
AND NOW (30-YEARS LATER) – DID THE WISHES COME TRUE?
M. Peckham
Abstract not received.

491 speaker
CLINICAL ONCOLOGY IN EUROPE 2011 AND BEYOND
D. Kerr
Abstract not received.

492 speaker
CLINICAL ONCOLOGY IN EUROPE 2011 AND BEYOND - THE ROLE
OF SURGERY
P. Naredi1
1
U MEÅ U NIVERSITY, Umeå, Sweden
Cancer care develops rapidly and the individual physician is replaced by themultidisciplinary team in the decision making. The evolution of new cancer
drugs based on increased knowledge in cancer biology catches most headlines but will for many years to come not replace potentially curative treatments. Radiotherapy and/or cancer surgery can and will be used with a curative intent. There will be improvements in surgical treatment to minimize thetrauma and enable an aging population to receive surgery.
Surgery will be less invasive. Laparoscopic procedures will not be the bigleap forward but the principles of video- and robotic-assisted surgery will enable development of high precision procedures in narrow areas. Nano techniques and tracers targeted against cancer specific receptors will facilitate
image guided surgery. The hunt for detectable cancer nodules can be motivated in several cancers, e.g. ovarian and colorectal cancer, when combinedwith adjuvant systemic treatments. A fifty percent five years survival after
liver resection for colorectal liver metastases shows that systemic spread ofcancer cells still can lead to localised disease worth resecting. The difficultylies in identification of cancer patients who will benefit from extensive cancer
surgery.
Clinical trials will define the role of surgery. This has been the case for rectal
cancer where a substantial decrease in local recurrences is observed after
the introduction of total mesorectal excision (TME). Trials have also shown
the added value of preoperative radiotherapy. In breast cancer diagnostic axillary dissection is replaced by sentinel node biopsy and most likely clinical
trials will define the patient population where there is limited advantage of additional axillary surgery.
Nothing indicates that insufficient (not radical) surgery can be substituted by
local radiotherapy or systemic treatments. These treatments should be considered as part of the multimodality treatment and not as salvage therapies.
Clinical trials will also define the role of surgery versus local ablative treatments for smaller localised cancers. Radiofrequency ablation or stereotactic radiotherapy become more common and need to be evaluated in wellconducted randomized trials. The indications for treatment with curative as
well as palliative intent must be decided.
The cancer surgeon from 2011 and beyond must be prepared to submit toa broad practical as well as theoretical training. Technical skills are necessary but the cancer surgeon must be perceptive, have knowledge in basic
science and understand the principles behind pharmaceutical and radiation
therapies. Surgery will be less costly than many other cancer therapies but
an increasing incidence of cancer and improved possibilities to treat cancer
patients will force surgeons as will as other cancer specialists to economizewith resources. The question will not be "can we resect the tumour" but "is
it indicated to resect the tumour". Rarely will the surgeon take that decision
herself/himself but instead as an important member of a team of cancer specialists.

S 200P ROFFERED PAPERW EDNESDAY, M AY 11, 2011493 speaker

Proffered paper

CLINICAL ONCOLOGY IN EUROPE 2011 AND BEYOND
J. Bourhis

Clinical Proffered Papers 5: Prostate & Gynaecology

Abstract not received.

495 oral

494 speaker

FIVE-YEAR SURVIVAL IN A RANDOMIZED PHASE III TRIAL OF
CONCURRENT RADIOCHEMOTHERAPY WITH 5-DAY VERSUSWEEKLY CISPLATIN IN LOCALLY ADVANCED CERVICAL CANCER
V. Nagy1 2 , C. Ordeanu3 , N. Todor4 , O. Coza1 3 , A. Rancea5 6

CLINICAL ONCOLOGY IN EUROPE 2011 AND BEYOND
M. Baumann
Abstract not received.

1

U NIVERSITY OF M EDICINE AND P HARMACY "I ULIU H ATIEGANU ", Medical
Oncology and Radiotherapy, Cluj-Napoca, Romania
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Radiotherapy
Departement, Cluj-Napoca, Romania
3
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Brachytherapy,
Cluj-Napoca, Romania
4
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Biostatistics,
Cluj-Napoca, Romania
5
U NIVERSITY OF M EDICINE AND P HARMACY "I ULIU H ATIEGANU ", Oncological Surgery, Cluj-Napoca, Romania
6
O NCOLOGY I NSTITUTE "P ROF.D R . I ON C HIRICUTA ", Oncological Surgery,Cluj-Napoca, Romania
2

Purpose: The comparison of the 5 year results obtained by two radiochemotherapy (RCT) regimens: 5-day vs weekly cisplatin at 326 patientswith locally advanced cervical cancer.
Materials: Patients with stage IIBIIIB squamous cell cervical carcinoma wererandomly assigned in two therapeutic arms: A) concurrent RCT with cisplatin
20mg/m x 5 days, at 21 day interval or B) concurrent RCT with cisplatin 40
mg/m/day weekly during radiotherapy. External beam radiotherapy (EBRT)
was delivered to the pelvic region using 15MV x-rays in daily fractions of 2
Gy, 5 days/week, four- field technique. A cervical boost was given using
the X-rays arch technique or high-dose-rate (HDR) intracavitary brachytherapy using iridium-192 isotope. At 46 Gy/pelvis + 10 Gy/boost, patients wereclinically evaluated according to local response: in stage IIB, they optionally
underwent surgery or continued concomitant RCT and in stage III only patients with good response (reduction of the lateral parametrial invasion) wereoperated. Surgery (radical abdominal hysterectomy with bilateral pelvic lymphadenectomy) was performed 46 weeks after the end of RCT. Patients withradical RCT immediately continued RT until 64 Gy/32 fractions/pelvis and 14
Gy boost/central tumor volume with concomitant CT (schedule according torandomization).In this study 326 patients were included from a single institution between March, 2003 and March, 2005:164 in arm A and 162 in arm
B.
Results: 160(49%) patients were in stage IIB, 103 (31.5%) in stage IIIA, and63 (19.5%) in IIIB. The median age was 48 years (range 24-70 years), themedian tumor size was 4 cm in both arms (range 1- 8 cm), and the medianfollow up was 62.8 months.After administration of the RCT dose of 46 + 10
Gy with cisplatin 20 mg/mp x 5 days or 40 mg/mp/weekly, 201(62%) patients
underwent surgery: 93 (57%) in arm A and 108(67%) in arm B.Comparing
the 5 year survival rate obtained by the two RCT regimens even though bothoverall survival (OS) (78% in arm A vs 72% in arm B) and DFS (73% in arm
A and 69% in arm B) show a tendency to superiority in arm A, the difference
isn’t statistically significant.Local relapse free survival obtained in arm A wassuperior (87%) compared to arm B (77%) (p<0.01).Sixty one (18.7%) local
relapse and 43(13.2%) distant metastasis were registered. In arm A, the local
relapse rate was twice lower (12,8%) then in arm B (24.7%) (p<0.01) while
distant metastasis were equal in the two therapeutic groups (22, respectively
21).
Conclusions: The 5 day cisplatin RTCT-regimen was superior to weekly
cisplatin-regimen regarding the local control and the 5 year local-relapse-freesurvival.
496 oral
IMPORTANT MORTALITY REDUCTIONS BY SHORT TERM ANDROGEN DEPRIVATION AND RADIOTHERAPY FOR LOCALLYADVANCED PROSTATE CANCER: 10 YEAR TRIAL DATA FROMTROG 96.01
J. Denham1 , A. Steigler2 , D. Lamb3 , D. Joseph4 , S. Turner5 , J. Matthews6 ,C. Atkinson7 , J. North8 , D. Christie9 , N. Spry4 , T. Keen-Hun10 , C. Wynne7 ,W EDNESDAY, M AY 11, 2011
C. D’Este11
U NIVERSITY OF N EWCASTLE, School of Medicine and Public Health,
Newcastle, Australia
2
U NIVERSITY OF N EWCASTLE, Callaghan, Australia
3
U NIVERSITY OF OTAGO, W ELLINGTON, Wellington, New Zealand
4
S IR C HARLES G AIRDNER H OSPITAL, Perth, Australia
5
W ESTMEAD H OSPITAL, Sydney, Australia
6
AUCKLAND C ITY H OSPITAL, Auckland, New Zealand
7
C HRISTCHURCH H OSPITAL, Christchurch, New Zealand
8
D UNEDIN H OSPITAL, Dunedin, New Zealand
9
P REMION , T UGUN, Queensland, Australia
10
P ETER M AC C ALLUM C ANCER C ENTRE, Melbourne, Australia
11
U NIVERSITY OF N EWCASTLE, Centre for Clinical Epidemiology andBiostatistics, Newcastle, Australia

1

P ROFFERED PAPER

S 201

7; 1.5 / 1.0cm: 7 vs.12). In total, 49 men have recommenced hormonal
treatment for recurrent disease. 8/64 men with PSA failure remain on an observation policy alone with a median duration of 7.5 yrs;2 more have diedof non-prostate cancer causes without treatment. Of the 40 patients with local or metastatic failure: 19/21 were from the 64/74 Gy and 20/20 from the
1.0/1.5cm margin groups, respectively. Hormonal therapy was restarted in
26/23 men from the 64/74Gy groups and 26/23 from the 1.0/1.5cm margingroups, respectively.
Conclusions: To our knowledge, this is the longest follow-up of any dose
escalation trial in prostate cancer available. As yet there is no clear survival
benefit for the dose escalated group or reduction in control with the smaller
RT margin. It is notable that 62% of deaths have been non-prostate cancer
related.Ref: 1. D P Dearnaley et al Br J Cancer 2005.92(3): 488498
498 oralPurpose: The TROG 96.01 trial determined whether 3 and 6 months shortterm neo-adjuvant androgen deprivation (NADT) produces important reductions in clinical progression and mortality following radiotherapy for locallyadvanced prostate cancer (PC).
Materials: Between 1996 and 2000, 818 men with T2b, c, 3, 4 N0 M0 wererandomised to 0, 3 or 6 months goserelin and flutamide prior to and during radiation to 66Gy to the prostate and seminal vesicles. Competing risks
and Cox regression analyses determined trial outcomes adjusted for baseline
age, tumour stage, Gleason score, PSA, and treatment arm.
Results: 802 men were eligible for analysis after median follow-up of 10.6
years. Compared to radiation alone, 3 months NADT reduced cumulative incidence of PSA progression (adjusted hazard ratio [HR] 0.72, 95% CI [0.570.90] p=0.003), clinical progression (HR 0.62 [0.46-0.85] p=0.002), and secondary therapeutic intervention (STI) (HR 0.65 [0.50-0.83] p=0.001), andimproved event-free survival (HR 0.63 [0.52-0.77] p<0.001). Six months
NADT produced greater reductions in PSA progression (HR 0.57 [0.46-0.72]
p<0.001), clinical progression (HR 0.47 [0.35-0.64] p<0.001), STI (HR 0.46
[0.35-0.59] p<0.001), as well as a greater improvement in event-free survival(HR 0.51 [0.42-0.61] p<0.001). It also reduced prostate cancer-specific mortality (HR 0.49 [0.32-0.74] p=0.001) and all-cause mortality (HR 0.63 [0.480.83] p=0.001). Sensitivity analyses showed that the outcome benefits from
6 months NADT would be maintained had 74Gy rather than 66 Gy been delivered.
Conclusions: Six but not 3 months NADT produced highly significant improvements in all efficacy outcomes following radiation in locally advancedPC.
497 oral
PHASE III PILOT STUDY OF DOSE ESCALATION USING CONFORMAL RADIOTHERAPY IN PROSTATE CANCER: LONG TERMFOLLOW UP
A. Creak1 , E. Hall2 , A. Horwich1 , R. Eeles3 , R. Huddart1 , D. P. Dearnaley1
1
T HE I NSTITUTE OF C ANCER R ESEARCH AND T HE R OYAL M ARSDEN NHSF OUNDATION T RUST, Academic Urology Unit, Sutton, United Kingdom
2
T HE I NSTITUTE OF C ANCER R ESEARCH, Clinical Trials and Statistics Unit
(ICR-CTSU), Section of Clinical Trials, Sutton, United Kingdom
3
R OYAL M ARSDEN H OSPITAL T RUST & I NSTITUTE OF C ANCER R ESEARCH,
London, United Kingdom
Purpose: Radical conformal external beam RT, in conjunction with initial androgen suppression, is a standard form of management of localised prostatecancer. This trial evaluated the role of dose escalation and the appropriate
target volume margin and was the ’pilot study’ for the national MRC RT01 trial.
Initial results were reported in 2005[1]. We now report long term follow-up.
Materials: Eligible patients had histologically proven T1b-T3b N0 M0 prostatecancer. There was no limit on pre-treatment prostate specific antigen (PSA)
levels. After an initial 3-6 month period of androgen suppression, 126 men
were recruited from a single centre between July 1995 and December 1997.
The RT target volume included prostate and all or part of seminal vesicles.
Treatments were randomised using a 2 x 2 factorial trial design A) to deliver
a dose of 64 Gy with either a 1.0 or 1.5 cm margin around the tumour volume and B) to treat either with or without a 10 Gy boost to the prostate alone(64/74 Gy groups). Tumour control was monitored by PSA testing, clinical examination. Follow up was updated from the hospital electronic patient record
system supplemented by direct GP and patient contact. Stratified log-rank
tests were used to compare survival data between randomised margin anddose groups with hazard ratios (HR) calculated from Cox proportional hazards models.
Results: Median follow-up is 13.6 yrs (range 1.1-15) and 70/71 of living men
have at least 12 yrs follow-up. Median age of living men at last follow-up is
78.9 yrs (range 64-89). Median presenting PSA level was 14 ng/ml (range
1142) and 72%/10% of men had moderately/poorly differentiated cancers.
64 men (50.8%) have developed biochemical PSA failure. 8 have developed
clinically detectable local failure only, and 32 have metastatic disease. Median overall survival is 14.4 yrs. No statistically significant differences havebeen observed between dose (64/74 Gy 28 vs. 22 HR=0.79 (95% CI: 0.451.38); p=0.41) or margin groups (1.5/1.0 cm 21 vs. 29 HR=1.47 (0.84-2.58);
p=0.18). 19 prostate cancer deaths have been reported (64/74 Gy 12 vs.

A DOUBLE-BLIND PLACEBO-CONTROLLED RANDOMIZED CLINICAL TRIAL WITH MAGNESIUM OXIDE TO REDUCE PROSTATE
MOTION FOR PROSTATE CANCER RADIOTHERAPY
I. Lips1 , C. van Gils2 , A. Kotte1 , M. van Leerdam3 , U. van der Heide1 , M.
van Vulpen1
U NIVERSITY M EDICAL C ENTER U TRECHT, Department of Radiation
Oncology, Utrecht, Netherlands
2
U NIVERSITY M EDICAL C ENTER U TRECHT, Julius Center for Health
Sciences and Primary Care, Utrecht, Netherlands
3
E RASMUS M EDICAL C ENTER R OTTERDAM, Department of Gastroenterology and Hepatology, Rotterdam, Netherlands

1

Purpose: In an attempt to reduce the intrafraction motion of the prostate,
several groups use magnesium oxide laxative during the course of radiotherapy. The rationale behind this approach lies in the hypothesis that magnesiumoxide diminishes the amount of gas pockets and causes a more stable rectal filling. We performed a double-blind, placebo-controlled randomized trial
to investigate whether magnesium oxide during external beam radiotherapy
reduces intrafraction prostate motion during treatment.
Materials: Between December 2008 and February 2010, 92 prostate cancer patients scheduled for 5-beam intensity-modulated radiotherapy (77Gy
in 35 fractions) using fiducial marker-based position verification, were randomly assigned to receive daily magnesium oxide (500 mg twice a day) or
placebo during radiotherapy. The portal images, taken of the first segment ofeach of the five beam directions, were used to determine the location of thegold markers within every treatment beam under the assumption of minimal
marker movement. The range of motion during each fraction was used as theintrafraction motion. The irradiation time of each fraction varied between 5-7
min. The primary outcome was the proportion of patients with clinically relevant prostate motion, defined as the proportion of patients who demonstrated
in ≥ 50% of the fractions an intrafraction motion outside a range of 2 mm.
Secondary outcome measures included quality of life and acute toxicity.
Results: In total, 46 patients per treatment arm were enrolled. The primary
endpoint did not show a statistically significant difference between the treatment arms with a percentage of patients with clinically relevant intrafraction
motion of 83% in the magnesium oxide arm as compared with 80% in theplacebo arm (P = 1.00). The average and standard deviation intrafraction
motion per patient was not statistically significant different between the twogroups either (Table 1). Concerning the secondary endpoints, exploratory
analyses demonstrated more patients with worsening of QoL in the magnesium oxide arm compared to the placebo arm. However, these differenceswere not statistically significant. Concerning toxicity, the magnesium oxidegroup showed slightly more GI acute adverse events, more loperamide wasprescribed for severe diarrhea and more patients decided to stop de study
medication because of side-effects compared to the placebo group. However, these differences were not statistically significant either.

Conclusions: Magnesium oxide is not effective in reducing the intrafraction
prostate motion during external beam radiotherapy. Magnesium oxide may
be harmful for patients because of worsened QoL and more toxicity. In conclusion, there is no indication to use it in clinical practice for the purpose of
reducing intrafraction motion.

S 202

P ROFFERED PAPERW EDNESDAY, M AY 11, 2011499 oral

500 oral

SALVAGE OR ADJUVANT?5Y-RESULTS OF THE “AIRO NATIONAL
WORKING GROUP ON PROSTATE RADIOTHERAPY” MULTICENTERPROSPECTIVE STUDY
F. Maurizi1 , A. Bonetta1 , R. Bortolus1 , F. Mauro1 , S. Barra1 , C. Iotti1 , S.
Nava1 , E. M. Bonetto1 , F. Salvi1 , V. Vavassori1 , M. Signor1 , F. Bertoni1 , G.
Moro1 , G. Malinverni1
1
AIRO N ATIONAL W ORKING G ROUP ON P ROSTATE R ADIOTHERAPY,
Department of Radiation Oncology, Italy, Italy

HYPOFRACTIONATED TOMOTHERAPY TREATMENT (HTT) IN
PROSTATE CANCER LYMPH NODAL RELAPSE DETECTED BY
11CCHOLINE PET/CT
G. Berardi1 , B. Pappalardi1 , C. Fiorino2 , C. Cozzarini1 , G. Guazzoni3 , R.
Calandrino2 , N. G. Di Muzio1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Radiation Oncology,
Milan, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Medical Physics,
Milan, Italy
3
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Urological department, Milan, Italy

Purpose: Using postoperative radiotherapy (RT) in patients (pts) at risk for
local recurrence is well established for many tumour sites. The postoperative
subgroup of the AIRO National Working Group on Prostate RT carried out
a multi-institutional prospective study to evaluate the impact of adjuvant RT(PORT) and salvage RT (SART) on biochemical outcomes in prostate cancer
pts.
Materials: Between January 2002 and December 2003, data of 440 pts(mean age: 65 years, range 42-81) treated with radical prostatectomy (RP)were collected by 13 Italian RT Departments. Of the 428 pts available for the
analysis, 302 (70.6%) received PORT (started <6 months after RP) and 126
underwent SART because of increasing PSA level after having been undetectable or persistently elevated PSA (> 6 months after RP). Gleason Score(GS) > 7 and positive surgical margins (SM+) have been shown by 280 pts(65.4%) and 302 pts (70.6%) respectively; 324 pts (75.7%) presented locallyadvanced disease (pT3-4), 35 (8.2%) positive pelvic nodes; 159 pts (37.3%)
revealed seminal vesicles invasion (SVI). RT was delivered to the prostatic
fossa alone in 68.6 % pts (mean dose of 67.8 Gy, range: 60-76). Pelvic RT
was delivered to 116 pts (31.4%). Androgen deprivation (AD) was prescribedto 44% pts. Among 126 SART pts, pre-RT PSA level was 1 ng/mL or less in
57 pts (45.2%).
Results: Of 428 pts available for analysis, 308 (72%) are disease free (DF)and 408 (95.3%) are still alive. Five year (5-y) overall survival and biochemical
control (BC) rate were 94.1% and 63.5% respectively. On univariate analysis,
PORT versus SART, SVI and GS > 7 significantly influenced 5-y biochemical
failure rate: 29% versus 52.1% according to adjuvant or salvage setting (p <0.001); 49.6 % pts with SVI versus 28.5% without SVI (p = 0.002); BC rate has
been 56.9% in pts with GS > 7 and 75% in pts with GS < 7 (p= 0.046). SM+,pathological T and N stages, AD or pelvic RT had no impact on biochemicalrecurrence rate. SVI and PORT versus SART were variables associated with
BC on multivariate analysis. Only pre-RT PSA level significantly influenced
disease free survival in SART setting: when the pre-RT PSA was 1 ng/mL or
less, 61.8% pts were disease free at 5 years compared with 38.2 % of thosetreated at PSA levels greater than 1 ng/mL (p= 0.02).
Conclusions: Pts in the adjuvant radiotherapy group and pts without
seminal vesicle invasion show better BC rates . Postoperative RT deliveredin high risk prostate cancer patients can reduce the impact of othercommon unfavourable prognostic factors (pT stage, positive surgicalmargins). Early referral for SART offers better disease control after radical
prostatectomy. This prospective multicenter study confirms outcomes ofother series.Radiotherapy Centers and Coordinators:
1. Aviano (CRO): R. Bortolus

Purpose: The aim of this work is to update the Hypofractionated Tomotherapy Treatment (HTT) feasibility-study, by evaluation of acute/late toxicity andclinical outcome, in lymph nodal relapse of patients (pts) already treated forprostate cancer. The role of 11C-Choline PET/CT in detecting prostate cancer recurrence and as a "guide" of Tomotherapy treatment was also evaluated.
Materials: From January 2005 to December 2009, 40 prostate cancer pts
with biochemical recurrence after prostatectomy (PSA0 > 0.2 ng/ml) andwith evidence of lymph nodal relapse at re-staging 11C-Choline PET/CT(PET/CT0), were treated with high dose moderate hypofractionated Tomotherapy treatment, guided by 11C-Choline PET/CT0 images. To evaluate treatment efficacy, PSA serum measurement (PSA1) (all pts) and 11CCholine PET/CT (PET/CT1) (n=19) were performed after treatment and compared to basal evaluations. In 36/40 pts PET/CT0 suggested the presenceof lymph nodal metastases (LNMs) at para-aortic and/or pelvic level while in
the remaining 4 at mediastinal level. PET/CT0 positive lymph nodes weretreated with high dose using a simultaneous integrated boost, as allowed by
Tomotherapy. A Mega-Voltage CT scan (MVCT) was performed before eachfraction to allow the right patient’s repositioning in order to reduce PTV margin and side effects to surrounding tissues. The doses ranged from 42 Gy
in 6 fractions to 74.2 Gy in 28 fractions. All patients continued the previous
hormonal therapy during HTT treatment.
Results: Radiation Therapy treatment was well tolerated in all patients. Witha median follow-up of 16 months (range: 3-54) 37/40 pts documented a significant reduction of PSA value after HTT. Of the 19 pts with PET/CT1 evaluation, 14 presented Complete Metabolic Response and 2 Partial Metabolic Response. During follow-up, none of the 40 pts had progression in the irradiatedarea and 3 showed disease in other sites. One died of tumour progression.
In 16/40 pts (5 genito-urinary [GU] and 11upper-gastro intestinal [uGe]) G1
acute toxicity was recorded. Only 2 G2 uGe and 3 G2 GU were observed. No
G3-G4 acute side effects were registered. Among the 21 pts with follow-up
greater than 12 months, only 5 had G1 late toxicity (1 Ge and 4Gu), none
showed G2-G3 late toxicity.
Conclusions: These preliminary data show that HTT-11C-Choline PET/CTguided with IGRT for precise repositioning of patients is safe and effective
in lymph nodal relapse of previously treated prostate cancer patients andcould be a valid alternative to chemotherapy . Although further evaluations
are necessary, the good rate of local control suggests that HTT treatment
guided by 11C-Choline PET/CT images may be reasonably proposed in thesepatients.

2. Biella (Osp Infermi ASL 12) G. Moro

501 oral

3. Bologna (Osp. Civile Bellaria) G. Frezza, F. Salvi

OPTIMAL DOSES AND REGIMENS OF DISTANT RADIOTHERAPYIN PATIENTS WITH BONE METASTASES.
E. Khmelevsky1 , G. Panshin1 , N. Dobrovolskaya2 , V. Solodki3

4. Candiolo (IRCC) G. Malinverni
5. Cremona (Ist. Ospitalieri) A. Bonetta
6. Cotignola (Villa M. Cecilia) F. Mauro
7. Genova (Ist. Naz. Tumori) S. Barra, M. Marcenaro
8. Modena (ASL Policlinico) F. Bertoni, P. Giacobazzi
9. Monza (Osp. S. Gerardo) S. Meregalli, E. Bonetto
10. Monza (Policlinico) S. Nava
11. Reggio Emilia (Osp. S. Maria Nuova) G.Zini, C. Iotti
12. Udine (Osp. S. Maria) M. Signor
13. Varese (Osp. Di Circolo) V. Vavassori

1
2
3

RSCRR, Department of Radiation Oncology, Moscow, Russian Federation
RSCRR, Chimiotherapie Ambulatoire, Moscow, Russian Federation
RSCRR, Administration , Moscow, Russian Federation

Purpose: Optimization of radiotherapy parameters in patients with bonemetastases.
Materials: Analysis was performed on randomized trial of 333 patients withbone metastases and 488 treatment radiation courses. Seventy one percentof the patients had breast cancer. Fourty five percent of the patients hadbone metastases that were located in the spine, 33% in the pelvis, 14% in the
femur and humerus. In trial was compared pain response and survival from3, 4 and 5-fractions treatment schedules of 6,5 Gy once in a five days, oncein two days or everyday and standard treatment schedule of 22-23 fractionsof 2 Gy daily. In this study patients enrolled after failed of systemic treatment.
Results: Overall response rate (complete or partial pain decrease in treatment zone) registered in 95,8%-100% cases independent of treatment doseand schedule. The study demonstrated complete response rate (CRR) independent of treatment schedule and significantly increased from 33,3% to50,4% and 65,9% in 2,3 and 4-fractions of 6,5 Gy each, respectively (p<0,03).
A multiple-fractions radiotherapy schedule 2 Gy each had the complete response rate 78,4% (p<0,01). CRR more frequently observed in patients withbreast and prostate cancer (67% and 63%, respectively) and more rarely inpatients with lung and renal cancer (47% and 30%, respectively) (p<0,05).
Also the metastases localization was not influence the CRR, it decreased
significantly only in sacrum isolated metastases -26,7% versus 68,2%, 59,6%

W EDNESDAY, M AY 11, 2011
and 56,7% of CRR in spine, pelvis and femur/humerus metastases, respectively. The pain relapse rate in the treatment zone was 8,2% , it independent
from primary tumor and metastases localization, dose and treatment schedules. However the time to pain relapse was longer in multiple-fractions treatment schedule 2 Gy each 23,5 months versus 9,6 months and 8,7 months
for 3- and 4-fractions of 6,5Gy each, respectively (p=0,06). Paravertebral soft
tissue fibrosis 1-2grade (RTOG/EORTC) significantly rare observed after 3fractions of 6,5 Gy each treatment than after 4-fractions and multiple-fractions
radiotherapy of spine (7,1% versus 31,3% and 26,3%, respectively, p<0,05).
Conclusions: For patients with bone metastases of breast and prostate cancer with expected overall survival more than 1 year preferable the treatment
schedule of three fractions of 6,5 Gy each, and for bone metastases of lungand renal cancer four fractions of 6,5 Gy each once in two days or everyday.

S YMPOSIUM

S 203

Symposium
Highlights in ESTRO Physics
502 speaker
BIRTH AND GROWTH OF PHYSICISTS CONTRIBUTION IN ESTRO
A. Dutreix1
1
I NSTITUT DE C ANCÉROLOGIE G USTAVE R OUSSY, Villejuif, France
30 years ago, a group of European radiation oncologists decided that it wastime to set up a new European Society independent of the existing Radiology
Societies in which 90% of the activities were devoted to Diagnostic.
During the preparation of the status of the new Society, as well as during thefounding meeting in Milan (September 1980), there have been hard discussions on the status of physicists and radiobiologists, but finally in 1981 they
have been accepted as full members.
When the first ESTRO meeting (to be held in London in June 1982) wasplanned, the scientific Committee asked Roy Parker from the Royal Marsden, and myself to present papers during the clinical sessions. However, in
December 81, I received a telephone call from Roy suggesting sessions dedicated to physics. Roy was very convincing and finally, by phone, (there was
no Fax and of course no e-mail) we decided about the program for 2 sessions
and the names of invited speakers. It was too late for free papers. Becauseof the short delay we called our colleagues by phone. All of them accepted
the challenge although there was no money available. Finally the 2 sessions
were a great success with 50 to 70 participants, including a non negligible
number of radiation oncologists.
After this first success, the number of Physics sessions and the number ofPhysicists attending the meetings increased regularly year after year. This
success was obvious during the third meeting in Jerusalem (1984), where therooms attributed to the physics sessions were much too small to accommodate the many participants crowding along the walls. The discussions wereso vivid that some of the sessions lasted one hour more than planned on the
program.
After a few years, some physicists suggested to the ESTRO board that biennial physics meetings be organised the same years as the ECCO-ESTRO
meetings. The first physics meeting in Budapest, in 1991, was a great success and the beginning of an always appreciated series.
In 1985, the first ESTRO training course on "Physics for Clinical Radiotherapy" has been organised in Leuven following a proposal of Prof. van der
Schueren. We were not sure of the necessity to organise a yearly course,
but the constant success of the course swept out all the hesitations. This firstcourse was rapidly followed by many courses on other specific topics.
In 1991 radiotherapy oncologists from five countries in the European Community succeeded in convincing the European Committee "Europe against
Cancer" to support the project of a European Network for Quality Assurancein Radiotherapy. This network performed dose checks in European Centreswith mailed TLDs, in close co-operation with the IAEA. The Measuring Centre
was set-up in Institut Gustave Roussy, France (IGR) whose previous experience was recognized. During a limited number of years the project was extended to a second measuring center at the Leuven University Hospital, andwas known as EROPAQ. In 1997, a permanent structure, EQUAL (for ESTRO
Quality Assurance Network), was set up in IGR and supported by ESTRO.
During the first two years EQUAL checked 235 Co-60 and x ray beams from
102 radiotherapy centers. The scope of this project was extended successively to electron beams and brachytherapy.
In 2004, for administrative reasons, the Equal Laboratory was converted into
a commercial company owned by ESTRO: Equal-Estro. However the locationof the Laboratory and the measuring procedures remained the same under
the responsibility of Attila Veres as chief physicist. Every year Equal-Estro
checks about 700 beam outputs and doses delivered by brachytherapy techniques. Dose checks have also recently been extended to modern radiotherapy techniques such as IMRT or tomotherapy, proton beams, and will soon
cover microbeams and Cyberknives.
The regularly increasing number of physicists members of ESTRO, 1175 thisyear, as compared with a total of 4500 members, (physicists are about 26 %of the total number of ESTRO members) shows clearly how successful is thecollaboration with radiation oncologists.
503 speaker
ESTRO- PHYSICS/ DEVELOPMENTS OF MEETINGS, COURSES,
AND RESEARCH PROGRAMMES DURING ALMOST 30 YEARS.
H. Svensson1
1
U NIVERSITY U MEÅ N ORRLANDS U NIVERSITETSSJUKHUS, Department ofMedical Physics, Umeå, Sweden
In the first ESTRO-meeting in London 1982 the physics program was organized by Andrutreix. She was very much behind a successful introductionof Physics in ESTRO. The first lecture in physics session 1 was given by
Svensson and Nahum on ‘How Accurate can Absorbed Dose to Tissue be
Determined. The present lecture will very much deal with the successive
improvement of accuracy in patient dosimetry and at the same time the intro-

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duction of much more advanced treatments.
The IAEA had in the 80-ties shown large deviations of absorbed dose determinations in centers in different countries of Europe. In addition reporting of
the target dose was also very different. The first teaching course in ESTRO‘Physics for Clinical Radiotherapy was set up 1985 to improve the situation.
The success with this course certainly trigged more specific courses that now
also are available.
The accuracy in treatments was supported through the ESQUIRE program,which included EQUAL and was set up in the mid 90-ties with support fromthe EU. We were also involved in the EC Directive 97/47 that states that Clinical Audit shall be carried out in radiotherapy.
In late 80-ties it was obvious that we sometimes needed discussions between
experts in physics, or in radiation biology that were too specific for our friends
in radiation oncology; the physics and the radiobiology committees were introduced 1989. The physics meeting was first set up 1991.
Finally, I will end with recent activities. My department introduced 1985 thevery first MLC for both MV X-rays and electrons. IMRT that was suggested
already 1987 and is now common practice. Particle therapy might be part of
the future!? The ENLIGHT program was supported by EU and organized by
ESTRO.
I am grateful to ESTRO that I have been involved in all these activities!

W EDNESDAY, M AY 11, 2011
organisations in developing guidelines for other topics in RT, which may thenat a later stage be endorsed by ESTRO-EIR.Although the direct participationof ESTRO in clinical trials is not anticipated, there may be an important roleof ESTRO Physics, in cooperation with EORTC and other organisations, indeveloping QA guidelines and performing actual QA of clinical trials, including audits of participating institutions. Another activity that requires a supranational approach is the construction of well defined data bases of clinicalrecords. Such a consistent set of European data would allow the further development of TCP and NTCP models. New developments in hadron therapy
may also benefit from a European approach in which ESTRO Physics could
be involved.Figure 1. Attentive audience during the First Biennial Meeting on
Physics in Clinical Radiotherapy, Budapest, 14-17 October 1991 (Courtesy
Tommy Knoos).

504 speaker
ESTRO PHYSICS: THE PAST, THE PRESENT AND WHAT’S NEXT?
B. Mijnheer1
1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Medical Physics, Amsterdam, Netherlands

Physicists have contributed to the development of ESTRO in various ways.
Already from the start of ESTRO, physicists were involved in the scientificprogramme. The idea of having specific physics sessions in ESTRO scientific meetings was a timely decision because at that time there was noother European scientific congress where medical physicists working in RT
departments could exchange their knowledge and experience. Furthermore,
the combined sessions with radiation oncologists gave physicists and clinicians insight in each other’s problems and paved the way to solve them together.In 1991 the First Biennial ESTRO Meeting on Physics in Radiotherapy was held (see figure). The format was more or less similar to the combined ESTRO meeting; a limited number of teaching sessions, high quality
scientific presentations of experts combined with proffered paper sessions.
The biennial Physics Meeting included, however, also many short presentations, often given by young physicists for whom it was the first time to present
their work at an international meeting. It was also a good moment to involve our central and eastern European colleagues in a number of ESTRO
Physics activities.Due to the fast development of new equipment many innovative treatment techniques became available. This created a large numberof challenges to the physics community which was reflected in the continuous
growth of ESTRO-guided scientific meetings, teaching courses and projects
devoted to these new technical developments. In addition to the biennial
Physics Meeting one-day workshops were held dedicated to an up to date
topic such as conformal radiotherapy (1997), verification of IMRT (2001), optimisation of IMRT (2003) and image-guided radiotherapy (2005).The radiation technologists (RTTs) joined us both during the biennial meeting, since2001, and as teaching staff in many courses. In this way a number of practical aspects related to the actual treatment of patients, including immobilisation techniques, quality assurance of the treatment and workflow issues
could be elucidated to a broad European audience.New developments in RT
can only be implemented in a safe and efficient way if representatives of all
disciplines work together in an optimal way. That message was already themain theme of the first ESTRO course in which physicists and clinicians were
present both as teaching staff and as participant. Currently there are many
ESTRO courses related to the implementation of technological advances inradiation oncology where combined teams of RT staff members profit fromeach other’s knowledge. Also the many ESTRO projects funded by the EU
and other organisations have contributed to the early implementation in many
clinics of new developments in RT.Close cooperation between physicists andclinicians is also the philosophy of GEC-ESTRO, the brachytherapy group in
ESTRO, which was formed in 1990. This group has a large impact in Europe
by improving education, collaboration and research in brachytherapy. Since
2004, the GEC-ESTRO annual meeting has been fully incorporated into the
ESTRO annual meeting every other year.Although the flow of technical innovations has not yet stopped, one of the major activities nowadays in a RT
department is the safe and efficient use of the technology already installed,
including the streamlining of the process. Non-optimal use of new tools suchas IMRT without adequate verification of patient position and dose delivery
may even cause a decline in clinical results compared to good conformal RT.
ESTRO has provided early guidelines for the QA of IMRT but further activities
in this field might be useful.Adaptive radiotherapy, making use of the possibilities of new image-guided technology, is currently pursued in a number of
RT centres. Still many problems have to be solved before these solutions canbe put into large scale clinical practice in busy departments. ESTRO-EIR is
involved in the development of clinical guidelines to which ESTRO Physics
may contribute in various ways including the use of advanced imaging tools
for target volume delineation. ESTRO Physics may also cooperate with other

Normal tissue dose response modelling beyond
the QUANTEC project
505 speaker
DVH-BASED PARAMETERS AND MODELS FOR TOXICITY PREDICTION
J. Deasy1
1

M EMORIAL S LOAN -K ETTERING C ANCER C ENTER, Department of Medical
Physics, New York, USA
Purpose: We will review the current ability of models to predict which patient/treatment plan combinations are likely to result in complications. Although the focus will be on standard fractionation, we will briefly mention
some issues relevant to hypofractionation.
Materials: We will briefly review the current status of normal tissue toxicity
predictive models that account for dose-distribution factors (Normal Tissue
Complication Probability, NTCP models), including the recent QUANTEC review and some recently published and ongoing efforts to validate QUANTEC
recommendations. NTCP models can probably be improved significantly byefforts in several areas we will discuss, including: combining biomarkers withdose distribution characteristics; combining data from multiple institutions thatcover a wider range of patient and treatment dose characteristics; more input from relevant small and large-animal experiments; better identification of
relevant tissues to an endpoint or structures within an organ that are relevant
to an endpoint an improved understanding of the impact of organ motion;and improved statistical model building methodologies. In addition, several
relevant areas of normal tissue radiobiology are relatively under-developed.
For example, little if anything is understood about the extremely shallow dose
response curves often seen for organ dysfunction endpoints (such as theparotid gland, kidney, lung, etc.). The role of stem cell rescue is only beginning to be understood and may have a profound impact as well. The previously accepted linear-quadratic framework for acute endpoints does not account for the fact the complications occur during a course of radiotherapy.
Conclusions: Predictive NTCP models will likely improve very significantlyin the next 5-10 years, but this will likely require a more dedicated effort tosystematically pool relevant, full-treatment data combined with blood-based
biomarkers.

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506 speaker
INTERNAL MOTION AND ITS INFLUENCE ON MORBIDITY PREDICTION FOR PELVIC ORGANS
L. P. Muren1 , M. Thor1 , A. Apte2 , L. B. Hysing3 , M. Alber4 , M. Söhn5 , S.
Thörnqvist1 , J. B. Petersen1 , M. Hoyer1 , L. Bentzen1 , A. Karlsdottir3 , J.
Deasy2
1
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics andOncology, Aarhus C, Denmark
2
M EMORIAL S LOAN -K ETTERING C ANCER C ENTER, Department of Medical
Physics, New York, USA
3
H AUKELAND U NIVERSITY H OSPITAL, Department of oncology and medical
physics, Bergen, Norway
4
U NIVERSITÄTSKLINIK FÜR R ADIOONKOLOGIE, Section for Biomedical
Physics, Tübingen, Germany
5L.-M AXIMILIANS -U NIV., K L . G ROSSHADERN, Department of Radiation
Oncology, München, Germany
In radiotherapy of pelvic tumour sites, internal organ motion gives rise toconsiderable uncertainty in the dose/volume parameters for important organs at risk (ORs). The deviations between the dose distribution calculatedon the basis of the pre-therapy planning scan and the doses actually received/accumulated in the ORs may be substantial. This presentation will
cover research activities addressing this challenge with regards to morbidity
prediction, focusing on the rectum and the bowel.
The studies on the rectum follow two different tracks. The first track includes
attempts to increase the correlation between morbidity and dose/volume parameters based on the planning scan only. Previous studies have included
use of volume expansion (PRV margins), showing increased correlations withmorbidity, in particular for intermediate dose levels when moderate-size margins were added. In on-going studies we have introduced a simple model for
rectum motion, and we are exploring the patterns of the resulting associations
between morbidity and simulated ’motion-inclusive’ dose/volume parameters
for both random and systematic motion (Fig. 1). The second line of research
has focused on rectum dose accumulation approaches, initially testing thecapabilities of currently available intensity-based deformable image registration algorithms. Studies have been performed on both CT and CBCT data
sets, showing clear limitations for both modalities. The motion patterns of thebowel are even more complex, and we have therefore developed a coverage
probability based method (for the small bowel) that on the basis of a limited
no. of CT data sets can produce patient-specific planning volumes that haveboth high specificity and sensitivity in predicting the location of small bowel
during the course of therapy. Future studies will reveal whether these volumes or the coverage probability distribution directly can be helpful both foroutcome prediction, as well as for treatment optimisation for this organ.
507 speaker
IMAGE-BASED DOSE-VOLUME EFFECTS PREDICTION
C. Fiorino1 , G. Rizzo23 , S. Broggi1 , G. M. Cattaneo1 , E. Maggiulli1 , E.
Scalco2 , G. Sanguineti4 , R. Calandrino1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
2
I STITUTO DI B IOIMMAGINI E F ISIOLOGIA M OLECOLARE , CNR, Segrate(Milano), Italy
3
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Nuclear Medicine,
Milan, Italy
4
J OHN H OPKINS U NIVERSITY, Department of Radiation Oncology,
Baltimore, MD, USA
Purpose: A quite new emerging field of investigation in the arena of dosevolume effects modeling concerns the possibility to use imaging findings toscore toxicity and/or predict clinically evident side effects. The increasing
availability of images of the irradiated organs at risk during the treatment due
to the spread of IGRT and adaptive radiotherapy will rapidly expand this fieldof investigation.
Material and methods: Morphological as well as functional imaging findings have been used to objectively score toxicity in a number of situations,mostly for lungs and parotids. Just looking to morphological changes, volume variations of irradiated organs may be a simple and generally available
information that can be considered in many cases as a "measure" of an effect due to radiation, as reported, for instance, for head and neck structures
including parotids, larynx and constrictor muscles. The development of methods to better quantify the spatial modifications of organs at risk may include
the use of elastic image registration. The Jacobian of the deformation field
is a parameter that can describe the entity of compression or expansion ofvoxels within a certain organ and has been already used for measuring thealterations of breathing patterns correlated to a reduced ventilatory capacityof lungs. The use of the Jacobian concept may be applied for monitoring deformations during and after the treatment, although proper validation of theelastic registration methods needs to be carried out. A recently suggested
extension of this concept is to consider the histogram of the jacobian map(namely, the jacobian-volume histogram, JVH) within the deforming organ.
We applied this concept to the case of parotid shrinkage showing how dosevolume effect may be enhanced when JVH-based parameters are use to de-S 206

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pict acute effects into the parotids.
Results: A strong correlation between JVH and planning DVH was found ina large population of patients. This result clearly suggests that quantitative
parameter describing parotid deformation may be explained by a model taking the shape of the dose distribution into account.
Conclusions: Image-based parameters recovered during and after the treatment are candidate to become more and more important in improving ourknowledge of dose-volume effects. Among the available methods, the use of
the Jacobian and of JVH is quite promising.

W EDNESDAY, M AY 11, 2011

Symposium
Improvement of staff and patient environment
508 speakerW EDNESDAY, M AY 11, 2011
Routledge LondonRichards, M (2003) Preface. In: Petrone, MA, ed. The
Emotional Cancer Journey. MAP Foundation, HoveZeki, S (2011) Artistic
Creativity and the Brain - Science Magazine (293) 5527 51-52Photograph ahelping hand image- sourced from :http://www.dreamstime.com/ "A Helping
Hand"

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Proffered paper
Accessibility of RT resources in Europe and theWorld
511 oralHEALING ENVIRONMENT FOR CANCER PATIENTS
A. van den berg

AVAILABILITY OF RADIOTHERAPY RESOURCES WORLDWIDE:THE IAEA DIRECTORY OF RADIOTHERAPY CENTRES (DIRAC)
E. Rosenblatt1
1
I NTERNATIONAL ATOMIC E NERGY AGENCY, Division of Human Health,
Vienna, Austria

Abstract not received.

509 speaker
THE ART OF HEALING IN HEALTH CARE-TRANSFORMING LIVES
THROUGH ART
B. Devlin1
1
M ARIE C URIE C ANCER C ARE, Belfast, United Kingdom
Art work has been shown to be beneficial in health care.It can be used asa channel for communication. Art activity can bring to consciousness thatwhich is unconscious. It is particularly helpful where individuals are unable
to express feelings, due to cognitive impairment, dysphasia or because theperson does not have the vocabulary to express their feelings. It addresses
the existential dimension, in that it can also help in the search for meaning. This is especially important when one is faced with a health issue or life
threatening condition. Art can improve one’s sense of self-worth as creativity is enhanced. Examples of art work produced by those who have faced
illness and its consequences clearly demonstrate some of the feelings andemotions they experienced.Art is very important in helping the brain reachits full potential.It introduces the brain to diverse cognitive skills that help us
unravel intricate problems. It activates the creative part of our brain - thepart that works without words and can only express itself non-verbally; theintuitive side of the brain.This is why art so important. It benefits the brain
by training it to think outside the box. It helps children understand concepts
more easily. It helps them to be greater achievers. In practice developmentof the artistic side of the brain helps in problem solving. It guides individuals to cerate solutions.It helps individuals to think beyond linear and logicalthinking (Eckert accessed online 16-10-2010).Semir Zeki, a former professor of neurobiology at the University College, London detailed the relationship between the development of cognitive abilities and the creative process.
He asserted that artistic expression is the key to comprehending ourselves.
He also considered art and its expression as an expansion of brain function. In other words, art helps the brain in its search for knowledge.So what
are the benefits of art on the brain? When individuals create art and reflect
on it, the processes, increase self-awareness, initiate awareness of others
and helps individuals cope with stressful, and traumatic experiences. Art enhances cognitive abilities and provides individuals with the ability to enjoy
the life-affirming pleasures of making art (Zeki, 2001).In relation to cancer
Fallowfield (2003) asserts that it is necessary to use modes of expression
other than language to capture what cancer really means to those affectedby itThe power of the arts as a channel for communication has been clearly
demonstrated through Michele Angelo Petrone’s (a professional artist) paintings of his cancer journey. (Fallowfield, 2003;Richards, 2003).Health caremust be holistic with emphasis on giving attention to the physical, social,emotional and spiritual domains of the individual. Art work helps address all
domains.The emphasis on maintaining the quality of life for individuals in ourcurrent health care philosophy and mission statements is partly met throughart work intervention.Qualitative findings through case studies of patients involved in art work demonstrate that clients regained a sense of control intheir lives, after being given the opportunity to explore personal issues andemotions (Pratt, 1998).Art work may be completed alone or in groups. Completed alone it allows time for reflection; in groups it can be therapeutic for
those with similar problems; for example a group who are experiencing griefthrough death or the thought of a loved one dying; or the losses individuals
experience when faced with life threatening illness. Bonding can develop withindividual group members helping, not only themselves but each other too as
they identify and externalise common feelings.Facilitators of art work must beaware of the potential power of the art medium; just as any image, sound or
smell can evoke a powerful reaction.It is important to highlight that it is theprocess of the art work that is important, not the artistic skill of the individual (Dalley, 1981). The environment must be psychologically safe. "Found
images" may be used as a "safety net" that is, an image on a postcard or
photograph which evokes some feeling for the individual. This is particularly
helpful if art work seems threatening initially.It is important that a creative
space is made in order to assist with the process of the art work, that is aspace that is physically comfortable and aesthetically appealing with the appropriate lighting.Breige Devlin MSc Health Promotion University of Ulster;
Advanced Diploma in Teaching Studies University of Ulster RN N. Ireland
SAA (The Society For All Artists) Member UKDalley, T(19981)Assessing thetherapeutic effects of art: an illustrated case study - Art Psychotherapy 7(1) 11-17Eckert, G http://www.self-help-healing-arts-journal.com/art-benefitsbrain.html accessed 16-12-2010Fallowfield, L (2003) Forward. In: Petrone
MA, ed. The Emotional Cancer Journey. MAP Foundation, Hove Pratt,M;
Wood, M (1998)eds. Art Therapy in palliative care The creative response

510 speaker
EFFECT OF LIGHT AND NATURE VIEW ON PATIENTS AND STAFF
IN A RADIOTHERAPY DEPARTMENT
H. Hellinga1 , M. Mast2 , J. Van Egmond2 , T. de Bruin - Hordijk1 , H.
Struikmans2
1
D ELFT U NIVERSITY OF T ECHNOLOGY, Delft, Netherlands
2
R ADIOTHERAPY C ENTRE W EST, The Hague, Netherlands
Purpose: Radiotherapy Centre West is situated in the basement of a large
hospital. The coffee room and waiting area are situated in this basement andaccess of daylight is present. This outside space lies below ground level andis on one side enclosed by the basement and on the other side by a concretewall. Recently a footbridge was placed above on ground level and a verticalgarden was made in the outside space.To investigate how this renovation haschanged the (subjective) perception of the indoor spaces and the rate of satisfaction of employees with the coffee room and patients with the waiting area
we have conducted a survey research.Methods and Materials: We investigated whether the perceived well-being of employees and patients was associated with a the reduction of daylight and addition of greenery in the coffee
room and waiting area. During different phases of the renovation questionnaires have been distributed to employees and patients.Results: The questionnaire results show that the rate of satisfaction with the coffee room andwaiting area has changed during the research, but the changes did not affectthe perceived well-being of both employees and patients. In the first phasesof the research, the reduced daylight in the coffee room made the space lookdarker, and was appreciated as less beautiful and pleasant. The footbridge
made the employees in the coffee room feel significantly less satisfied.In contrast, the footbridge did not affect the appreciation of the waiting area, andin the first three phases of the research the satisfaction level of the patients
did not change. The vertical garden made both the employees and patientssignificantly more satisfied with the indoor spaces. These spaces were described as more beautiful and more pleasant in the presence of the verticalgarden. Surprisingly, the coffee room was also found to be less dark than it
did before the vertical garden was implemented.Conclusion: We noted thatboth daylight and greenery play an important role in the perception of the hospital environment. In the coffee room the realisation of a vertical garden wascompensated for the loss of daylight. However, the research also showedthat employees of the hospital would like to have more access to daylightin their work environment and confirmed that both patients and employees
have a natural need for daylight and greenery, and that the presence of both
improves the visual quality of healthcare environments.

Purpose: The IAEA maintains a world directory of radiotherapy centres(DIRAC) which contains information on radiotherapy facilities, teletherapy andbrachytherapy equipment, imaging equipment, treatment planning, dosimetry
ancillary equipment and personnel. No other centralized database is currently
available describing the capacity to deliver radiotherapy worldwide.
Materials: DIRAC may serve as a basis for developing indicators that may
represent the status of radiotherapy in different countries, regions, of theworld as a whole. Such indicators include availability of radiotherapy machines per million populations and per crude cancer incidence; ratio between
Co-60 units and clinical accelerators, and for instance the relation between
brachytherapy capacity and the incidence of cervical cancer.
Results: Currently DIRAC encompasses 6985 radiotherapy centres operating 14.829 teletherapy and 2672 brachytherapy machines, which serve theglobal population of 6.6 billion people. These numbers suggest that on average, each teletherapy machine serves approximately 600.000 people. Thereis an average of 8, 1.2 and 0.2 teletherapy machines per million in high,middle and low income countries respectively. It is evident that access oflarge populations to radiotherapy services is inadequate and there is a significant need for additional radiotherapy facilities.The map depicts the numberof teletherapy machines per million inhabitants in 2010. Countries that appear in red are those that have between 5-15 machines per million. Thereare currently 49 countries (countries, independent territories and island nations) with no radiotherapy facilities at all. The number of teletherapy machines/1000 cancer cases plotted against the GNI per capita, reveals that as
the GNI increases so does the number of teletherapy machines, and that their
proportion is higher for North America, Western Europe and less for the AsiaPacific and Eastern Europe. This reflects the relatively higher investment inradiotherapy services in these regions.There are 30 operational proton beam
therapy centres worldwide and others under construction or expansion. As of
March 2010 there are five carbon ion therapy centres in Japan, Germany andChina and there are several more in preparation.

Conclusions: To approach the level of higher-income countries, countries oflower income would need to increase the availability of radiotherapy equipment by tenfold or more. Strategies to develop new facilities need carefulplanning and have to be accompanied by a substantial investment in trained
human resources.

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512 oral
50 YEARS OF THE IAEA DOSIMETRY LABORATORY WORK FOR
RADIOTHERAPY
J. Izewska1 , A. Meghzifene2
1
IAEA - I NT ’ L ATOMIC E NERGY AGENCY, Nuclear Sciences and Applications, Wien, Austria
2
IAEA - I NT ’ L ATOMIC E NERGY AGENCY, Wien, Austria
Purpose: The objective of this paper is to discuss the impact of the IAEA
dosimetry services for radiotherapy on dosimetry practices worldwide at the50th anniversary of the IAEA Dosimetry Laboratory (DOL).
Materials: DOL was set up in 1961 with the purpose to design a calorimeter and prepare a dosimetry system suitable for postal dose comparisons
for radiotherapy centres. At that time there were no dosimetry standards forthe dose calibrations in radiotherapy, although the methodology was underdevelopment in a few standards laboratories. First trial postal dose interhospital comparisons were conducted by the IAEA in 19651966 involving
Fricke dosimeters and TLDs. Eventually, the service was established basedon TLDs and it has been operated this way until today. In 1969, the first
TLD batch was sent to radiotherapy centres within the project called "Joint
IAEA/WHO Dose Intercomparison Service for Radiotherapy". In the next
decade efforts were made to establish national laboratories for dosimetry
standardization of radiation measurements in hospitals. These lead to theestablishment of the IAEA/WHO Network of Secondary Standards Dosimetry Laboratories (SSDLs) in 1976 with DOL acting as the Central Laboratoryof the Network. The Network started with 9 laboratories and this number
increased to over 30 in the following year.
Results: In 50 years of its operation, several developments took place in
DOL services. By 2010, the IAEA/WHO TLD audit service has verified thecalibration of more than 8000 radiotherapy beams in about 1700 hospitals in
120 countries. In the early years, the TLD service recorded approximately
50% audited beams having adequate calibration. This percentage of acceptable results has now increased to 96%. However, discrepancies in the beam
calibration are still observed and without an independent audit they may havenot been discovered and patients may have been treated incorrectly.Today,
35 years after its inception, the IAEA/WHO SSDL Network consists of 85
laboratories in 67 countries. The IAEA has provided support for the establishment of many SSDLs in developing countries. DOL calibrates dosimeters
for them this way transferring the dosimetry standards to the national level.
It organizes inter-laboratory comparisons to verify the quality of dosimetry
calibrations and operates dosimetry audit services to ensure that the dose
measurements by SSDLs are kept within internationally accepted levels.
Conclusions: The major role of IAEA has been in achieving the worldwide
coherence in radiotherapy dosimetry traceable to SI units. The IAEA/WHO
TLD audits for radiotherapy have brought improvements in dosimetry practices in several countries. The SSDL Newtork related activities have consolidated the international community involved in radiation metrology, assisted
individual SSDLs in carrying their functions in radiation measurements, andcontributed to the increase of overall expertise in dosimetry worldwide.
513 oral
STATE OF RADIATION ONCOLOGY IN THE UK
K. Benstead1 , J. Barrett2 , C. Beardmore3 , A. Beavis4
1
G LOUCESTERSHIRE O NCOLOGY C ENTRE, Cheltenham, United Kingdom
2
R OYAL B ERKSHIRE NHS F OUNDATION T RUST, Reading, United Kingdom
3
T HE S OCIETY AND T HE C OLLEGE OF R ADIOGRAPHERS, London, United
Kingdom
4
Q UEENS C ENTRE FOR O NCOLOGY AND H AEMATOLOGY, C ASTLE H ILL
H OSPITAL, Cottingham, United Kingdom
Purpose: Over 250,000 people in England are diagnosed with cancer every
year and around 130,000 die from the disease 1 .The projected need for radiotherapy was significantly underestimated 15-20 years ago.Detailed modellingsuggests that 52% of patients should receive radiotherapy as part of theirtreatment. In 2007, it was estimated that only 37% of cancer patients accessed this treatment2 . The NHS was delivering 30,000 fractions per million
population compared with the predicted need of 48,000 fractions per million. While radiotherapy capacity has increased, the demand has not increased
at the rate previously predicted and there remain variations in activity acrossthe country. It has been estimated that there is a two and a half fold variation in the number of fractions that are provided per million population between cancer networks. Increasing deprivation is correlated with lower ratesof access to radiotherapy (r=0.820)3 There is wide variation in throughput perradiotherapy machine. The average capacity of a radiotherapy machine iscurrently 7,000 fraction per year. The target, set by the government in 2007 is
8,7004 . A national modelling tool is being refined to allow prediction of radiotherapy demand locally and so enable appropriate radiotherapy capacity to
be planned. Collaborative working through multiprofessional work streams
has been encouraged through the National Radiotherapy Implementation
Group.Pressures on machine time, an ageing linac stock, heavy workloads
for clinical oncologists including increasing chemotherapy commitments, ashortage of therapeutic radiographers and physics staff, together with a lack

W EDNESDAY, M AY 11, 2011of a standard tariff for IMRT has led the UK to be slow adopters of IMRT andimage guided 4D adaptive radiotherapy 5 . Further linac instillations, including expansion machines, replacement programmes and satellite centres, atarget specifying the minimum IMRT activity per centre by disease site andthe development of a national tariff for IMRT should improve this in the near
future. Targeted training in IMRT for clinical oncologists in the UK is a significant educational need. An e-learning package focussing on IMRT developedby collaboration between all professional groups and supported by government funding will be launched in Spring 2011.In 2007 a streamlined process
to arrange proton treatment for patients outside the UK was developed. A
single proton facility is being planned to serve the UK 1.The establishment of
the Gray Institute for Radiation Oncology and Biology in Oxford and the National Cancer Research Networks has led to increasing activity in both basic
and clinical research. Phase 3 trials are allowing the development of national
standards for volume definition and fractionation regimens as well as providing external quality assurance for departments introducing IMRT. Academic
training fellowships have been developed to support trainees who aspire toa career in research. In 2010, a national appointment system for trainee
clinical oncologists was established and a competency based curriculum 6
with workplace based assessments was introduced. Competition for places
is intense and the calibre of successful candidates very high.. The development and implementation of a four tier career framework for the therapeutic
radiographers, with advanced and consultant radiographer practitioners supported with assistant practitioners offers the opportunity to enhance the skills
mix across the service enabling adaption of roles to meet local service need
7,8,9
. A new training scheme for dosimetrists is being piloted and the intended
introduction of further "assistant" and "practioner" roles into the physics workforce may partially address the shortage of clinical scientists 10 . This has
all been achieved through multi-professional collaboration11. Therefore, while
the effect of the proposed changes to the NHS, with GP commissioning andincreased private provision, on radiation oncology are unclear, the excellenceof our trainees gives us justified grounds to hope that the service will continue to improve.In summary there remain some problems with capacity andthe introduction of more advanced planning techniques, however, considerable work is underway across the UK to support service development. This
will be achieved through multi-professional collaboration.
1. Department of Health (2011) Improving Outcomes for Cancer: A Cancer Strategy .
London: Department of Health (http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/ PublicationsPolicyAnd Guidance/DH_123371 )2. Radiotherapy in England in 2007: modelled demand and audited activity. Williams MV, Drinkwater, KJ; Clin Oncol (R Coll Radiol) 2009; 21(8); 575-90.
3. Geographical variation in radiotherapy services across the UK in 2007
and the effect of deprivation. Williams, MV, Drinkwater KJ; Clin Oncol(R Coll Radiol) 2009; 21(6):431-40.
4. NRAG (2007) Radiotherapy: developing a world class service for England. Report to Ministers from National Radiotherapy Advisory Group
26 February 2007
5. Survey of the availability and use of advanced radiotherapy technology
in the UK. Mayles WP; Radiotherapy Development Board; Clin Oncol(R Coll Radiol) 2010; 22 (8); 636-42
6. http://www.gmc-uk.org/education/postgraduate/approved_curricula_systems.asp
7. College of Radiographers (2000) A Strategy for the Education and Professional Development of Therapy Radiographers. London: The College of Radiographers
8. College of Radiographers (2005) Implementing Radiography Career
Progression: Guidance for Managers. London: The College of Radiographers
9. College of Radiographers (2006) Positioning Therapeutic Radiographers within Cancer Services: Delivering Patient-Centred Care. London: The College of Radiographers
10. Department
ofHealth(2011)
Modernising
Scientific Careers.
London.
Department of Health (www.dh.gov.uk/en/Aboutus/Chiefprofessionalofficers/
Chiefscientificofficer/DH_086661 )11. The Royal College of Radiologists, The Society and The College of Radiographers, The Royal College of Nursing, the Institute of Physics andEngineering in Medicine (2002 Breaking the Mould: Roles, Responsibilities and Skills Mix in Departments of Clinical Oncology. London.
The Royal College of Radiologists.
Materials:
Results:
Conclusions:W EDNESDAY, M AY 11, 2011
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ORION®: SIMPLE AND EFFECTIVE METHOD FOR SYSTEMICANALYSIS OF EVENT OCCURRING IN HOSPITAL PRACTICE
F. Debouck1 , J. Bourhis2 , G. Noël3 , H. Petit1 , L. Ravinet1 , T. Didier1
1
AFM42 C ONSULTING, Chambourcy, France
2
I NSTITUT G USTAVE R OUSSY, Villejuif, France
3
C ENTRE PAUL S TRAUSS, Strasbourg, France
Purpose: Morbimortalty review is now recommended by the French Health
Authority (Haute Autorit SantAS]) in all hospital settings. As regularly done inradiotherapy centres, this a posteriori analysis may be completed by a systemic analysis of precursors which may potentially result in medical damage,even thought no damage has yet occurred.Frequently overloaded, medical
teams do not favour analysis of precursors as a current practice as far as it
requires a method difficult to learn and difficult to use. It is the reason why
ORION® has been set up.
Materials: ORION® is based on experience acquired in aeronautics whichis the main precursor in risk management since aircraft crashes are considered as unacceptable even though the mortality from aircraft crashes is
extremely low compared to the mortality from medical errors in hospital settings. ORION® is an easy-to-learn but nevertheless rigorous analytic method.
It permits to build the chronology of facts resulting in the considered event,to identify the causes of the event and to propose corrective actions aiming
at improving the overall system of working. The systemic analysis is divided
in 6 steps: Step I: Collecting data Step II: Rebuilding the chronology of facts
Step III: Identifying the deltas Step IV: Identifying contributing and influential
factors Step V: Proposing actions to put in place Step VI: Writing the analysis report. When identifying contributing and influential factors, four kindsof factors favouring the event are considered: technical domain, working environment, organisation and procedures, human factors. Although they are
essentials, human factors are not always correctly considered. The systemic
analysis is done by a special committee, set up in each service of the hospitaland including all categories of people acting in the setting: assistants, nurses,
health managers, quality managers, pharmacists, physicians &Results: ORION®is now used in more than 400 French hospital settings for
systemic analysis of either event precursors or morbimortality cases. Generally, and particularly in 145 radiotherapy centres, systemic analysis of event
precursors is carried out through CREX (Comite Retour d’Expence), monthly
committees analysing experience feedback.
Conclusions: As shown by the number of hospital settings currently themethod, ORION® , the easy-to-use analytic method is successful. It permits
medical teams to make systemic analysis of both event precursors and medical events leading to effective corrective actions favouring right hospital working and improving patients’ care.
515 oral
FAST TRACK FOR HEAD AND NECK CANCER PATIENTS: THE
STORY OF THE DANISH NATIONAL STRATEGY FOR ACCELERATED DIAGNOSIS AND TREATMENT OF CANCER
C. Grau1 , K. Toustrup1 , A. Christensen2 , N. M. Lyhne3 , M. C. Alanin4 , M. T.
Bruun5 , T. H. Junge6 , M. A. Bruhn7 , J. B. Jespersen7 , C. A. Kristensen8 , E.
Andersen6 , C. Godballe5 , C. Buchwald2 , T. Bundgaard1 , J. Johansen5 , K.
Lambertsen7 , H. Primdahl1 , J. Overgaard1
1
A ARHUS U NIVERSITY H OSPITAL, Aarhus C, Denmark2
C OPENHAGEN U NIVERSITY H OSPITAL - R IGSHOSPITALET, Copenhagen,Denmark
3
A ARHUS U NIVERSITY H OSPITAL, Aarhus N, Denmark
4
N AESTVED H OSPITAL, Naestved, Denmark
5
O DENSE U NIVERSITY H OSPITAL, Odense, Denmark
6
U NIVERSITY H OSPITAL H ERLEV, Herlev, Denmark
7
A ALBORG S YGEHUS S YD, Aalborg, Denmark
8
T HE F INSEN C ENTER - R IGSHOSPITALET, Copenhagen, Denmark
Purpose: Significant tumor progression has been observed during the waiting time for treatment of head and neck cancer. A meta-analysis of clinicalobservations in head and neck, breast and other cancer types has shown thatthe risk of local recurrence increases with increasing waiting time for treatment. The increase in local recurrence rate may translate into decreased
survival rates in some clinical situations. A Danish study (Primdahl et al. Acta
Oncologica 2006) has shown that compared to 1992, the waiting time before
start of radiotherapy was significantly longer in 2002 (median 70 versus 50
days).
Materials: A pilot study of fast track accelerated diagnosis of head and neckcancer was conducted in Aarhus during 2007. This study tested structuralchanges in infrastructure for rapid diagnosis, including
Telephone hotline to coordinator, for GP and patientsReserved slots for clinical examination in ENT department
Pre-booked radiology slots
Fast pathology reporting (1-3 days)
Multidisciplinary tumor boards and clinics twice weekly
Results: The pilot study in Aarhus proved that it was possible to reduce

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median time from cancer suspicion to treatment start from 56 days to 29
days. The current waiting times for all Danish head and neck centers will beanalyzed in a follow-up study of the 1992-2002 survey (data available April2011).Based on research data and supported by public demand,"fast track"
was declared a national Danish policy for all patients with suspicion of cancer,
starting from 2008. This means that patients with suspicion of cancer are
given the highest priority in the health care system. The total course, fromcancer suspicion to start of treatment, must be carried out without any delays(<3 weeks).
Conclusions: Waiting time for treatment is potentially hazardous. Reducing
waiting time by fast track implementation is possible, but requires a substantial concerted effort of the involved health sectors. The effect on survival
outcome is still to be proven. Authors on behalf of the Danish Society for
Head and Neck Oncology (DSHHO) and The Danish Head and Neck Cancer
Group (DAHANCA).

Clinical Proffered Papers 6: Normal Tissue Effects
and Quality of Life516 oral
ASSOCIATION OF BREAST TUMOUR BED SEROMA WITH POSTOPERATIVE INFECTION AND LATE NORMAL TISSUE TOXICITY:RESULTS FROM THE CAMBRIDGE BREAST IMRT TRIAL
M. Mukesh1 , G. Barnett21 , J. Cumming1 , J. Wilkinson1 , M. Moody1 , C.
Wilson1 , C. Coles1
1
A DDENBROOKE ’ S H OSPITAL, Department of Oncology and Radiotherapy,
Cambridge, United Kingdom
2
U NIVERSITY OF C AMBRIDGE, Department of Oncology and Radiotherapy,
Cambridge, United Kingdom
Purpose: There are two main surgical techniques for managing the tumour
bed after breast cancer excision. Firstly, closing the defect by suturing thecavity walls together, and secondly leaving the tumour bed open thus allowing
the seroma fluid to collect. There is debate regarding which technique ispreferable, as it has been reported that a post-operative seroma may increase
infection rates and increase late normal tissue side effects. We investigate
whether the presence of seroma is associated with increased rates of postoperative infection, cosmesis and normal tissue toxicity at two years after
completion of radiotherapy in a large group of patients with early stage breast
cancer.
Materials: Data on 633 patients who participated in the Cambridge Breast
IMRT trial were used. The seroma was identified on the axial CT images
at the time of radiotherapy planning and graded as not visible/subtle or easily visible. The following parameters were collected prospectively as part of
the Cambridge Breast IMRT trial: presence or absence of post-operative infection, two year normal tissue toxicity assessed using serial photographs,
clinical assessment and self assessment questionnaire. STATA 10 version
was used for the statistical analysis to test for association between seroma
and these parameters.
Results: The presence of easily visible seroma was associated with increased risk of post-operative infection (OR=1.80, 95% Confidence Interval
1.21, 2.68; p=0.004). On univariate analysis, presence of breast seroma
was associated with worse breast cosmesis (p= 0.02), tumour bed induration(p=0.01) and breast oedema (p=0.01) at 2 years. On multivariate analysis,
the presence of seroma was associated with tumour bed induration (p=0.005)
and breast oedema (p=0.02) but was no longer associated with worse overall
cosmesis (p=0.2). There was no significant association between the presence of seroma and the development of either breast shrinkage or breast
pain at 2 years on univariate and multivariate analysis.
Conclusions: The presence of seroma at the time of radiotherapy planning
is associated with increased rates of post-operative infection. It is also an
independent risk factor for tumour bed induration and breast oedema at two
years. Early results suggest possible worse overall cosmesis in patients with
post-operative seroma. The updated results for normal tissue toxicity at five
years will be presented.

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QOL / OUTCOMES OF AN INTERNATIONAL PHASE 3 TRIAL
OF INTERMITTENT V CONTINUOUS HORMONE THERAPY FORRELAPSED PROSTATE CA
G. G. Duncan1 , C. O’Callaghan2 , K. Ding2 , D. P. Dearnaley3 , C. Higano4 ,E. Horwitz5 , S. Malone6 , L. Goldenberg7 , M. Gospodarowicz8 , L. Klotz9 , J.
Crook10
1
B.C. C ANCER AGENCY - VANCOUVER C ENTRE, Radiation Oncology,
Vancouver, Canada
2
NCIC, Clinical Trials Group, Kingston, ON, Canada
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiation Oncology,
Sutton, United Kingdom
4
U NIVERSITY OF WASHINGTON, Medical Oncology, Seattle, WA, USA
5
F OX C HASE C ANCER C ENTER, Radiation Oncology, Philadelphia, USA
6
OTTAWA H EALTH R ESEACH I NSTITUTE, Radiation Oncology, Ottawa,
Canada7
VANCOUVER P ROSTATE C ENTRE, Vancouver, Canada
8
P RINCESS M ARGARET H OSPITAL, Radiation Oncology, Toronto, Canada
9
S UNNYBROOK R ESEARCH I NSTITUTE , H EALTH S CIENCES C ENTRE,
Urology, Toronto, Canada
10
BC C ANCER AGENCY - C ENTRE FOR THE S OUTHERN I NTERIO, Radiation
Oncology, Kelowna B.C., Canada
Purpose: PR7 is an NCIC CTG led UKICR-SWOG-CTSU randomized trial
which demonstrates equivalence in overall survival (OS) between intermittent
androgen suppression (IAS) and continuous androgen deprivation (CAD) inpatients with PSA progression following previous radical therapy of prostatic
cancer. We report on the quality of life (QOL) experiences of IAS and CAD.
Materials: 1386 patients were randomized. Secondary endpoints included
time to castration resistance, time to testosterone (and potency) recovery(IAS cases), lipid profile, as well as QOL using EORTC-QLQ30 and trial specific checklist data. Stratification included time since RT (1-3 years vs > 3
years), initial PSA (3-15 ng/ml vs >15 ng/ml), prior radical prostatectomy, andprior hormone therapy.
Results: The median age was 74.2 years. With a median follow up of 6.9
years, 524 died (268 (IAS) vs. 256 (CAD)), with equivalent OS (HR 1.02,
95% C.I. 0.86 1.21). Significant toxicities included hot flashes, impotence,loss of libido, urinary freq/urge, and fatigue but only hot flashes are less frequently reported (90% IAS vs 93% CAD, p=0.04). 35% of IAS cases had
testosterone recovery to baseline levels (rates differ by country). Cross sectional QOL analysis shows a range of benefits for IAS cases at multiple timeframes. Using a 10 point change from baseline score as a clinically meaningful response, IAS patients had better QOL with respect to global healthstatus, physical function (p < 0.01), fatigue (p < 0.01), urinary problems (p =0.01), hot flashes (p < 0.01), desire for sexual activity (p < 0.01) and erectile
function (p < 0.01).
Conclusions: This large study shows QOL benefits for patients on intermittent therapy but the differences in QOL were small using conventional QOL
methodologies. The observed QOL gains are made without any adverse effect on disease progression or survival.

W EDNESDAY, M AY 11, 2011
ing to mean esophageal dose (MED). The estimated TD50 (dose corresponding to 50% incidence of the endpoint) was MED=63.4 Gy. The median MED
for all patients was 31.6 Gy for patients receiving 3D-CRT (range 0.2-55.6
Gy), 31.2 Gy with IMRT (range 0.9-62.7 Gy), and 15.9 Gy for PBT (range
0-56.6 Gy). Using either relative or absolute values of VDose, the optimal
threshold dose for predicting Grade 3 or higher esophagitis was 42.2 Gy, withrelative volumes more strongly predictive of high-grade esophagitis than absolute volumes. When examining relative volumes, cut-off doses between 15
Gy and 45 Gy produced similar fits to the data.
Conclusions: MED and the incidence of high-grade esophagitis are decreased with PBT compared to 3D-CRT and IMRT in patients receiving highradiation doses for NSCLC. The volume of esophagus receiving 40 Gy or
higher (either absolute volume or relative) is a reasonable cutoff for predicting high-grade esophagitis, regardless of technique. Current studies are in
progress to update the clinical and dosimetric data, and to determine why theincidence of high-grade esophagitis in this early subset of IMRT patients ishigher than that found in patients treated at our institution during later time
periods.

W EDNESDAY, M AY 11, 2011519 oral
RECOVERY OF SALIVARY GLAND TOXICITY: CONTRALATERALPAROTID GLAND (PG) VERSUS BILATERAL SUPERFICIAL LOBESPAROTID SPARING IMRT (PARSPORT VERSUS PARSPORT II)
A. Miah1 , S. Gulliford2 , K. Harrington1 , S. Bhide1 , K. Newbold3 , C. Nutting1
1
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Head and Neck Unit, Sutton, United Kingdom
2
T HE I NSTITUTE OF C ANCER R ESEARCH, Department of Radiotherapy
Physics, Sutton, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Head and Neck Unit,
Sutton, United Kingdom
Purpose: Intensity modulated radiotherapy has demonstrated an advantage
over conformal radiotherapy in reducing the incidence of high grade long term
xerostomia . The aims of this study are to establish whether there is a difference in the incidence of high grade xerostomia with different PG sparing techniques and whether different tolerance doses for recovery of salivary function
exist for the superficial lobes of the parotid gland when compared to the entire
parotid gland following IMRT.
Materials: An attempt to spare the superficial lobes of both PGs was described as an alternative to sparing the entire contralateral (C/L) PG in asingle institution phase II study (PARSPORT II); a mean dose constraint of 24
Gy was applied. Acute (NCI CTCAE v3.0) and late toxicity (LENTSOMA and
RTOG) scores were recorded prospectively. The superficial lobes of both PGs
were outlined in the PARSPORT trial cases as a comparator . The groups
were dichotomised to subjective xerostomia scores G0-1 (recovery) versus≥ G2 (no recovery). Mean doses to the entire PG and combined superficial
lobes for each group and differences in incidence of toxicity were compared.
Results: In the PARSPORT II study, 71 patients received IMRT for base of
tongue cancers and had one year follow up. These data were compared tooutcomes reported in the 63 patients from the PARSPORT trial. Mean doses
and incidences of high grade subjective xerostomia at 1 year are describedin Table 1. Additionally, significant differences in the mean doses received by
the superficial lobes of both PGs associated with recovery versus no recovery
of xerostomia (LENTSOMA) were demonstrated in both PARSPORT II (26.1
Gy vs 28.5 Gy, p=0.03) and PARSPORT IMRT (28.0 Gy vs 35.0 Gy, p=0.003).
The differences in C/L PG mean doses were non-significant.
Conclusions: Attempting superficial lobes PG sparing may offer a higher incidence of recovery of salivary function compared to whole C/L PG sparing
alone in oropharyngeal cancers. Tolerance doses of each structure will bepresented.
1
Nutting CM et al. Parotid-sparing intensity modulated versus conventional
radiotherapy in head and neck cancer (PARSPORT): a phase 3 multicentre
randomised controlled trial. Lancet Oncology 2011; 12:127-36.
2
Acknowledgements: We would like to thank the ICR-Clinical Trials andStatistic Unit for providing follow up PARSPORT Trial data

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PREDICTIVE
DOSIMETRIC
FACTORSFOR
HIGH-GRADEESOPHAGITIS IN PATIENTS TREATED FOR NON-SMALL CELLLUNG CANCER (NSCLC) WITH DEFINITIVE 3D CONFORMAL
THERAPY (3D-CRT), INTENSITY MODULATED RADIATION THERAPY (IMRT), OR PROTON BEAM THERAPY (PBT)
D. Gomez1
1
U.T. M.D. A NDERSON C ANCER C ENTER, Houston, USA
Purpose: Esophagitis is a common toxicity in the treatment of NSCLC withdefinitive radiation. The aim of this study was to evaluate dosimetric predictive factors for high grade esophagitis in patients treated with three different
radiation techniques.
Materials: From 1999-2008, 678 NSCLC patients were treated with radiation
therapy (RT) to a prescription dose of at least 60 Gy and had dosimetric information available. No patients had received prior radiation treatment to thethoracic region. The stage distribution was as follows: stage I, 13.5% (n=92);
stage II, 6.5% (n=45); stage IIIA, 33% (n=224); stage IIIB, 38% (n=256); stage
IV, 6% (n=42); recurrent, 3% (n=19). The modality distribution was: 3D-CRT
68% (n=462); IMRT 18% (n=122); PBT 14% (n=94). Thirty eight percent
of patients (n=255) underwent induction chemotherapy, and 72% of patients(n=488) received concurrent chemotherapy. The mean esophageal volume
was 35.7 cc (range 10.6 103.6 cc), and the mean RT dose to the esophagus
was 29.9 Gy (range 0-62.7 Gy). The Lyman model was fitted to the data for
Grade 3 or higher esophagitis, and probit analysis was performed to determine the threshold doses for which absolute and relative values of VDose,the volume of esophagus receiving a dose higher than the threshold, weremost strongly associated with high-grade esophagitis.
Results: The incidence of grade 3 or higher esophagitis with the three RT
techniques was: 3D-CRT, 14% (n=65); IMRT, 27% (n=33); PBT, 6% (n=6).
The estimated volume parameter for the Lyman model was n=1, correspond-

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THIRD INTERNATIONAL CONSENSUS ON PALLIATIVE RADIOTHERAPY: A JOINT ASTRO, ESTRO, CARO & TROG INITIATIVE
P. Hoskin1 , E. Chow1 , L. Dawson1 , C. Hahn1 , T. Holt1 , S. Lutz1 , G.
Rodrigues1 , M. N. Y. Tsao1
1*O N BEHALF OF THE I NTERNATIONAL PALLIATIVE R ADIOTHERAPYC ONSENSUS 2010 COLLABORATORS, London, United Kingdom
Purpose: This International Consensus was established to re-visit the guidelines developed from the 2nd International Consensus meeting held in theyear 2000. The remit was extended to include not only bone metastasis, brain
metastasis and non small cell lung cancer (NSCLC) but also liver and spinal
metastasis including metastatic spinal cord compression. Working groups
were convened comprising members from each of the participant organisations to review the current literature and undertake patterns of practice surveys from which a consensus for future practice could be defined.
Consensus Findings:
Bone Metastasis

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Single dose radiotherapy (RT) remains the treatment of choice for most patients with equivalency shown in multiple prospective randomised trials compared to multifraction schedules. Supplementary treatment with bisphosphonates, radionuclides and surgery should also be considered. Future trials will
inform the role of re-treatment of painful bone metastasis and the use of dose
escalation with stereotactic body radio-surgery. Metastatic Spinal Cord Compression
MRI remains the gold standard for diagnosis and the role of MRI in screening asymptomatic patients is increasing. Steroids using dexamethasone inintermediate doses of 8mg daily is recommended and for patients with neurological symptoms with a prognosis greater then 3 months a neurosurgicalopinion should be mandatory. There is a wide range of fractionation practicein spinal cord compression related primarily to institution rather than an evidence base and further trials are urgently needed. Brain Metastasis
Solitary brain metastases should be treated with surgery or radiosurgery (RS)and whole brain RT (WBRT), or RS alone; for limited multiple metastases anda prognosis >3 months either WBRT, RS or WBRT and RS should be considered; multiple metastases otherwise should receive WBRT unless the life
expectancy is < 3 months when symptomatic measures only may be preferred. Predictive tools such as the RPA or GPA should be used for patient
selection. NSCLC
Palliative RT is indicated for stage IV and selected stage III disease based on
factors such as performance status, respiratory function, symptoms, weightloss and patient preference. Whilst short course palliation has a role in patients with poor performance status, intermediate doses of 30Gy in 10 fractions or more have benefit for those with good performance status. There is
no routine role for brachytherapy but it may be useful for retreatment. Liver
Metastasis
RT is effective in local ablation of focal liver metastases but high level evidence is lacking. Trials are needed evaluating the role of stereotactic RT for
focal metastases and low dose RT for palliation of multiple metastases.
Materials:
Results:
Conclusions: Radiotherapy has an important role in the management ofmetastatic disease. The consensus guidelines will be published during 2011
to guide future practice and research.
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TEETH: THE POORLY DEFINED ORGAN-AT-RISK
R. Thompson12 , R. Schneider1 , C. Ares1 , A. Lomax1 , E. Hug1
1
PAUL S CHERRER I NSTITUTE (PSI), Center for Proton Therapy, Villigen PSI, Switzerland
2
M ONTEFIORE M EDICAL C ENTER , A LBERT E INSTEIN C OLLEGE OF
M EDICINE, Bronx, USA

Purpose: Irradiation of pediatric facial structures can lead to severe impairments of permanent teeth later in life. However, few reports address this toxicity of radiation on the developing dentition. We therefore focused on primaryand permanent teeth as organs-at-risk, investigating the ability to identify thedeveloping tooth bud in children and infants and to obtain individual tooth
dose distributions.
Materials: We reviewed 14 pediatric patients treated at our institution between 2003 and 2009 who received radiation of >20 Gy(RBE) to one or moreprimary or permanent teeth. Patients (ages 1-16 years) were treated by spotscanning proton therapy with 50-59.4 Gy(RBE) in 23-33 daily fractions for avariety of tumors including rhabdomyosarcoma (n=10), sarcoma (n=2), teratoma (n=1), and carcinoma (n=1). Individual teeth were contoured on transverse image slices from the original planning CT scan, and DVH data wereretrospectively obtained from the total delivered treatment, calculated using
in-house treatment planning software.
Results: All primary teeth and permanent incisors, canines, and first molars
were individually contoured without difficulty in all patients, regardless of age.
This included 8 infants and toddlers (ages 1-4 years). However, CT-based
identification of the two permanent premolars and second molars correlatedroughly with expected time of initial tooth calcification, with all teeth being
readily identifiable by 4 years of age. DVH analysis showed a wide range
of intra-individual dose distribution to the teeth, with an average minimum
single-tooth dose of 0.57±1.04 Gy(RBE) and an average maximal dose of
48.42±12.12 Gy(RBE). Predictably, each patient exhibited markedly different
patterns of dose exposure, depending on the geometry of the PTV target andits proximity to the dentition.
Conclusions: Assessment of dose distribution to individual teeth is possible by CT-based imaging, though delayed calcification may complicate tooth
identification in the youngest patients. There is ample evidence to suggestthat dose exposure should be determined for each single tooth, and that thepatterns of dose exposure to the dentition vary markedly among patients (dependent on the incident fields, target volumes, and anatomy). Importantly,
the doses observed demonstrate significant sparing of exposure to large areas of the dentition as dose fall-off in proton treatments is rapid, generally
avoiding a "low-dose bath" of the distal dentition. Irrespective of therapeuticmodality, this study demonstrates the ability to identify and contour teeth intheir early developmental phases and to obtain individual DVH’s. Correlationof dose with dental complications is in progress, and will hopefully improve
future clinical risk assessment and lead to OAR dose constraints to minimize

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toxicity to the developing teeth.

W EDNESDAY, M AY 11, 2011
which are inherently flexible. The potential for organic photolvoltaics in solar
power generation is being keenly researched however the technology can beadapted to measure radiation. The added advantage of these materials isthat they can be printed on an inductrial scale so that they offer the potential for relatively inexpensive radiation detectors.Initial results are presentedof the efficency and radiation hardness of these devices.
Materials: An organic photovoltaic device was developed using a thin film
blend of the conjugated polymer poly(3-hexythiophene-2,5- diyl) and thefullerene derivattive phenyl -C61-butyric acid methyl ester. The prototype
evaluation devices were fabriacted on glass substrate. These devices typical have external quantum efficiences of upto 80% at 500nm. The devices
were coupled with a Gadolinium Oxysulphide phosphor to convert the incident
high energy photons into optocal photons.The devices were irradiated using
an Elekta synergy linac at 15, 10 and 6MV. The devices were placed at dmax
under WTe solid water. The devices were irradiated and the photovoltaic current measured. A conventional diode was also used in the measurement
geometry for comparison.
Results: The devices have a sensitivity of approximately 0.86 C m-2 Gy-1 ,control experimetns without the phosphor layer show that X-rays can be detected directly but the sensitivity is over two orders of magntiude lower. Importantly the current measured from a Scanditronix EDP-10 diode was a factorof 14 times lower.The radiation durability of the devices were measured byirradiating them to more than 10 kGy. Despite the intial radid fall of dose thesensitivity remained high even at that total dose. It is estimated that a regularly used in-vivo dosimeter would receive a dose of approximately 1000 Gy
per annum, hence these devices would be resilient in regular clinical use
Conclusions: We have prototyped a megavoltage X-ray detector consistingof a phosphor layer in contact with an organic photovoltaic fabricated from
P3HT:PCBM. X-rays incident on the phophor generate luminescence whichis then detected by the organic photovoltaic. The well matched spectral response between the phosphor and the organic photovoltaic led to a sensitivity
higher than a commercial silicon detector along with excellent stability - 70%
retained sensitivity after irradiation to 10 kGy.Our measurements demostratethat these organic based detectors have a linear response, high sensitivity ,and high radiation hardness. This suggests that they may find application asa real time dosimeter for in-vivo dosimetry of intensity modulated beams.

Physics Proffered Papers 11: In vivo and online
dose measurements
522 oral
TREATMENT PLANNING SYSTEM BASED EXIT DOSIMETRY
R. Cufflin1 , E. Spezi1 , A. Millin1 , D. G. Lewis1
1
V ELINDRE C ANCER C ENTRE, Medical Physics, Cardiff, United Kingdom
Purpose: The aim of this work is to set-up an accurate, efficient and costeffective method of verifying our clinical IMRT plans during treatment using
an Electronic Portal Imaging Device (EPID). We have developed an efficient
exit dosimetry verification technique enabling the dose delivered during IMRT
to be calculated at an exit plane defined within the treatment planning system (TPS) to be coincident with the position of the EPID fitted on the treatment linac. A series of pre-calculated correction factors, dependent on patient
thickness, field position and shape, are used to convert the dose at the EPID
level to image intensity, for comparison against EPID images acquired during
treatment. This technique enables verification results to be analysed quickly
in a clinical setting and has the advantage that it uses the same TPS that wasused for initial dose calculation of the patient IMRT plan.
Materials: All dose distributions are planned and optimised on Oncentra
Masterplan (OMP, Nucletron). The patient CT data-set is exported into MATLAB software, where it can be manipulated and the water equivalent ’EPID’layer added at the appropriate level and position, before being re-imported
into OMP. Full forward Monte Carlo (MC) calculations of portal dose wereused to compare dose in water with dose in EPID both within the field andbeneath the MLC, enabling dose conversion factors to be obtained. In addition, correction for non-uniform backscatter from the Varian EPID and its
supporting structures was required.
Results: MC calculations of exit dose in water-equivalent material at the
EPID level verified the ability of the TPS to calculate the dose correctly forthis situation. There was very good agreement between the collapsed conealgorithm and MC simulation, to within 0.5% for the thicknesses investigated,
although the pencil beam algorithm overestimated the exit dose at the EPID
level by up to 14%. For the first 68 IMRT beams evaluated, derived from 4
pelvic and 4 head and neck IMRT plans, an average of 95% of points passed
a gamma criterion of 5%, 5mm, comparing very well with the full MC simulation results. In addition, the technique has identified changes in exit dose resulting from patient anatomy variations between planning CT and treatment.
Figure 1 illustrates the beam’s eye view and gamma map for a pelvic IMRT
field. It can be seen that a small area, corresponding to patient bowel, failed
the gamma criterion.

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EVALUATION OF ONEDOSEPLUSTM MOSFET DOSIMETER FOR IN
VIVO DOSIMETRY IN HIGH ENERGY X-RAY BEAMS
N. Jornet1 , P. Carrasco de Fez2 , M. E. Alayrach3 , T. Eudaldo2 , R. Garcia3 ,M. Ribas Morales2
1
H OSPITAL DE S ANT PAU, Servei de Radiofísica i Radioprotecció,
Barcelona, Spain
2
H OSPITAL DE LA S ANTA C REU I S ANT PAU, Servei de Radiofísica iRadioprotecció, Barcelona, Spain
3
I NSTITUT S AINTE C ATHERINE, Avignon - Cedex 02, France

Conclusions: Although still in the development phase, the results of thistreatment planning system exit dosimetry technique are very promising, theresults obtained showing very good agreement with measurements and fullforward MC calculations. The technique enables results to be analysed
quickly in a clinical setting and has the advantage over alternative methodsof forward prediction of EPI images in that it uses the same TPS and dose
calculation algorithm that was used for initial dose calculation of the patient
IMRT plan.
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DEVELOPMENT OF FLEXIBLE IN-VIVO DOSIMETRY ARRAY
S. Weston1 , J. Kingsley2 , D. Lidzey2
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Department of Medical Physics and Engineering, Leeds,
United Kingdom
2
U NIVERSITY OF S HEFFIELD, Department of Physics and Astronomy,
Sheffield, United Kingdom

1

Purpose: To accurately verify the delivery of anIntensity modulated field(IMRT or IMAT) it is necessary to measure the delivered fluence at a large
number of points across the whole of the field. This is imnpracttical with conventional diode based dosimetry because of the diffuclty with psotioning andcorrelating a large number of individual detectors. Ideally what is required
is a two dimensional array which will conform to the patients surface. Thisis difficult with silicon based technologies because of the inherent rigidity ofthe materials. Organic electronics can be used to create elctronic devices

Purpose: This work aimed to characterise a commercialised single-use
MOSFET detector (OneDosePlusTM , Sicel) for entrance in vivo dose measurements in 6 and 18 MV x-rays. This detector has two characteristics thatmake it different from other commercialised MOSFET detectors: it is calibrated at the factory and it incorporates a build-up cap. As it is designed for
one use, the user cannot calibrate it and has to use the calibration provided
by the manufacturer. Therefore, measurements were performed to determine
the level of accuracy for entrance dose measurements using the manufacturers’ pre-set calibration and correction factors (CF).
Materials: Five different lots of OneDosePlusTM detectors (from 2007 to2010) were used for this study. In global 400 detectors were tested. All
measurements were performed on a Varian Clinac 2100 CD linear accelerator. The dose measured with MOSFET detectors placed on the surface ofa plastic water (CIRS) phantom was compared to the dose measured at thedepth of dose maximum with an 0.6 cc cylindrical ionisation chamber. Film
dosimetry was used to measure the perturbation of the radiation field behind these detectors.The irradiation conditions were not entered in the reader
for any measurements therefore the correction factors were applied manuallyfrom the fits given in the lot calibration sheet provided by the manufacturer.
The reading, in cGy, was the voltage shift multiplied by the individual factory
calibration factor. The intra-lot reproducibility for different doses, accuracyof the calibration factors in reference conditions, temperature dependence ofthe dose response, and accuracy of the dose measurements under clinicalirradiation conditions were studied for all lots. The field size, SSD, wedge
and angle correction factors given by the manufacturer were validated. The
uncertainty of dose measurements was estimated.
Results: The inter-lot reproducibility depended on the lot ranging from of 4%(1SD) to 2.5% (1SD) for 1 Gy irradiation. The linearity of the response withdose was excellent for all lots. The accuracy in dose determination in reference conditions was better than 1% for all lots and both energies except for
two lots: 9% dose underestimation for both energies and 6% underestimation for 6MV. These two lots were retired from the market after contacting the
manufacturer. The mean and the SD of differences between MOSFET andion chamber doses measured in clinical conditions are shown in table1. Field
size, SSD and wedge CF measured agreed with those used by the manufacturer within the uncertainty (2 to 3% depending on the CF). The detectors

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presented a strong angular dependence; 10% under-response at 45 for 18
MV x-rays. The attenuation under the detector at 5 cm depth was 2.5% for 6
MV x-rays and 2% for 18 MV x-rays. No response temperature dependence
was found. The uncertainty of entrance dose measurements depended on
the lot being on average 8% (2SD). The last lot presented a better behaviour(reproducibility and accuracy) than the previous ones which could indicate an
improvement in the manufacturing and also in the factory calibration procedures.

Conclusions: OneDosePlusTM MOSFET detectors cannot be used on patients without verification of their pre-set calibration factors. Due to the highuncertainty of dose measurements the ±7% action levels, as recommended
by AAPM (AAPM report no 87 2005) or ESTRO (ESTRO booklet no.5 2001),
could be too tight for these detectors. As differences among readings fromtwo detectors can be as high as 5% two MOSFET should be placed at thesame time. Care should be taken in doing this, as the perturbation on thedose distribution will increase and this would further limit the number of sessions that can be controlled by in vivo dosimetry.
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CAPABILITIES OF RADPOS, 4D IN VIVO DOSIMETRY SYSTEM
J. Cygler12 , A. Cherpak12 , S. Monica3 , J. Seuntjens4 , R. MacRae5 , J.
Pantarotto5 , G. Perry6
1
T HE OTTAWA H OSPITAL C ANCER C ENTRE, Ottawa, Canada
2
C ARLETON U NIVERSITY, Department of Physics, Ottawa, Canada
3
H ÔPITAL M AISONNEUVE -R OSEMONT, service de radiophysique, Montréal,
Canada4
M ONTREAL G ENERAL H OSPITAL , M C G ILL U NIV., Medical Physics Unit,
Montréal, Canada
5
T HE OTTAWA H OSPITAL R EGIONAL C ANCER C ENTRE, Radiation Oncology,
Ottawa, Canada
6
T HE OTTAWA H OSPITAL C ANCER C ENTRE, Radiation Oncology, Ottawa,
CanadaPurpose: The RADPOS system is a new in vivo dosimetry tool capable ofsimultaneously recording dose and spatial position of points on a patient’s
body. Testing was conducted to evaluate the system, first in a lab setting, thenusing a deformable lung phantom, and finally during a clinical trial involving
lung cancer patients. The goal was to determine its potential as a 4D invivo dosimetry system, for quantification of variations in patients’ breathing
patterns and to monitor inter-fraction variations in dose.
Materials: One RADPOS detector was positioned directly inside a tumour
embedded in a deformable lung phantom, and another detector inside thelung portion of the phantom, outside the tumour. The phantom and RADPOS system was then used to simulate a free-breathing and an adaptive
treatment. Measurements were taken and compared to CT imaging-based
positions and treatment planning dose calculations. For the clinical trial, patient measurements were taken during the acquisition of 4DCT data and daily
treatments. Three RADPOS sensors were positioned at marked points on thepatient’s chest and abdomen and a fourth reference detector was placed on
the couch. Position coordinates of the sensors were read in real-time and thetotal dose was read at the end of each fraction.
Results: The RADPOS has dosimetric characteristics similar to microMOSFET detectors, when the latter is used standalone. Displacement measurements have an accuracy between 1.1-1.3 mm, within an optimal volume withrespect to the transmitter. The stability of the position readout is within 0.21
± 0.07 mm and is not affected by the linac beam. Compared to positional information extracted from CT imaging, the accuracy of the RADPOS reported
position is better than 2.5 mm inside the deformable phantom and total doses
reported by RADPOS agreed to within 1.5-5.0% of treatment planning doses.
The clinical trial has been completed with multiple measurements taken on
ten patients. The standard deviation of the measured dose at each point
ranged from 2.5 to 13.7 cGy over all patients, depending on detector location. Variations in breathing patterns were largely patient-specific; however
several common patterns have been identified. Nine patients showed a moderate or strong negative correlation between period of breathing and timesince planning CT and for five of the patients, the daily amplitude measured
during treatment was greater than the amplitude at the time of the 4DCT in
the majority of the treatment fractions.

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Conclusions: RADPOS trials indicate that the system can be used as anefficient quality assurance tool for 4D radiation therapy. The clinical study has
shown that the RADPOS system can provide accurate real-time feedback regarding patient motion in addition to dose measurements. Breathing patterns
were found to be patient-specific and should be monitored to ensure accurate
positioning and treatment delivery.

of deformable registration and GPU-based computation, accurate dose accumulation may be achievable in the next years.

Purpose: 3D EPID-based dose reconstruction has proven to be a feasible
tool for in vivo dosimetry of IMRT and VMAT. However, it is an open issue toestablish guidelines for 3D dose evaluation that provide the same sensitivity
as the usual methodologies applied for 2D dose distribution analysis. This isessential for VMAT EPID-dosimetry where 2D analysis is practically impossible. The aim of this study was to assess which interpretation of the 3D results
can provide the same error detection rates as 2D analysis per beam. For
that purpose, 3D gamma dose evaluation methods were compared with ourclinically routinely applied 2D gamma analysis of in vivo EPID dosimetry for
12 selected IMRT treatments that include a variety of errors.
Materials: Using a back-projection dose reconstruction model based in thetransmission of measured images with and without the patient in the beam,
2D and 3D in vivo dose distributions were calculated for IMRT treatmentsof different treatment sites. During 3 treatments significant errors were intercepted in one or more beams (Red cases), 4 treatments had minor errors (Orange cases) and 5 treatments were approved automatically (Green cases).
2D gamma analysis (3%/3mm criterion) was used to evaluate the results forthe 2D dose distributions applying as parameters the mean gamma (gmean),gamma 1% (g1%), and the percentage of gamma values below 1 (%g1). 3D
gamma analysis, using the same gamma parameters but comparing 3%/3mm
and 2%/2mm criteria, was performed to the 3D dose distributions. Furthermore, DVHs of the reconstructed 3D dose distributions were calculated andcompared with the DVHs obtained from the TPS.
Results: For all cases, the gamma evaluation results in 3D using 2%/2mm
showed similar error detection rates as the routinely applied 2D gamma evaluation applying 3%/3mm criteria (Table 1). Consequently, 3D gamma analysis
with 3%/3mm criterion showed less error detection sensitivity. The differences between the mean dose in the PTV determined by the TPS and the
EPID (∆Dmean) deduced from the DVHs showed that this parameter canalso be used for error detection. All Green cases yielded values for ∆Dmean
1%, while the average value of ∆Dmean for Orange and Red cases were1.11% ± 0.01 and 1.80% ± 0.02, respectively.

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practice and we expect that the use of this method will improve the agreement
between calculations and IN-VIVO measurements.

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ANGULAR CORRECTION OF THE IN-VIVO RECTUM PROBEREADINGS IN ROUTINE GYNECOLOGICAL BRACHYTHERAPYTREATMENT.
V. Stserbakov1
1
N ORTH E STONIA R EGIONAL H OSPITAL, Department of Radiotherapy,
Tallinn, Estonia

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FROM 2D TO 3D DOSE EVALUATION FOR IN VIVO IMRT VERIFICATION
P. Camargo1 , R. Rozendaal1 , S. Joep1 , J. J. Sonke1 , M. van Herk1 , B.
Mijnheer1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, 2nd Radiation Therapy Department, Amsterdam, Netherlands

W EDNESDAY, M AY 11, 2011

Conclusions: This preliminary study shows that 3D gamma evaluation on
3D reconstructed dose distributions can give similar error detection rates as
the 2D gamma methods routinely applied in our institution. However, thegamma-parameters used in 3D should be narrower than the ones used in 2D.
The results also indicate that certain parameters deduced from the DVHs are
sensitive enough for error detection.

Purpose: The aim of this study was to find out the cause of disagreement between point doses values, which were measured (IN-VIVO) and calculated forsome patients. For this purpose additional studies of the detector response
as a function of the angle of the diode to the direction of radiation comingfrom the source were performed.
Materials: All measurements were done with rectal Fivefold Detector Probe
PTW Type 9112. For angular calibration set-up the adapter for probe and theAfterloading Calibration phantom for IN-VIVO calibration PTW T 9193 wereused. An angular calibration scale was applied on the phantom body for determining the rotation angle of the detector to a radiation source (angle step= 15). Accumulated charges (nC) of the diodes (collecting time = 1 min) were
measured with electrometer PTW VIVODOS in Multichannel Mode. GammaMed Plus remote afterloader with source Ir-192 (decay factor ~2) wasused. The 0.6 cc Farmer chamber type 30001, placed inside the adapter
30001 on the opposite side of the phantom, was taken as a reference chamber.
Results: The directional dependence (up to 12%) of IN-VIVO detector response was found. In the figure 1a normalized readings of the rectal probes(R1 R5) as function of the diode angle to the radiation source φ are shown.
Additionally, it can be noticed that the manufacturer has built detectors inside
the catheter directionally on about the same angle (figure 1c) and therefore
behavior of the detectors‘ readings is quite consistent. Surprisingly, the signals of the diodes were higher (few %) when the radiation was parallel to theplates of the detectors (angles 0◦ and 180◦ ).

Physics Proffered Papers 12: Image registrationand segmentation
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CLINICAL EVALUATION OF A SPEED OF SOUND ABERRATIONCORRECTION ALGORITHM IN QUANTITATIVE ULTRASOUNDAIDED IMAGE GUIDED RADIOTHERAPY.
D. Fontanarosa12 , S. van der Meer1 , F. Verhaegen13
1
MAASTRO C LINIC, Physics Research, Maastricht, Netherlands
2
T ECNOLOGIE AVANZATE TA, RD, Torino, Italy
3
M C G ILL U NIVERSITY, Montreal, Canada
Purpose: To investigate the clinical impact of a recently introduced speed ofsound (SOS) aberration correction algorithm in ultrasound (US) imaging systems for image guided radiotherapy (IGRT). The SOS algorithm was applied
to four prostate cancer patients and two liver cancer patients to assess in areal clinical application the extent and spatial distribution of the corrections.
Materials: The developed algorithm transforms the simulation computerized
tomography (CT) scan, available in IGRT applications co-registered to the USscan, into a SOS map, using an empirical relationship between the physicaldensity, provided by the CT scan, and the SOS. These SOS values are thenused to correct the distances in US images. Four prostate cancer and twoliver cancer patients, for whom both simulation co-registered CT/US scans
and treatment US scans were available, were considered. All patients had
an US scan at the simulation stage (USref) and daily scans at the treatment
stage (UStrt). The same simulation CT scan was used to correct all USref
and UStrt images. For this work, the latter was always chosen as the last US
scan performed in order to have the maximum time period between the two,and therefore possibly also the maximum difference in patients’ shape. The
SOS algorithm was applied and a cumulative shift image was plotted (Fig.
1), which shows the total spatial shift undergone by each voxel due to SOS
aberration correction.

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TOMOTHERAPY IN-VIVO DOSIMETRY FOR PROSTATE TREATMENT YIELDS EXCELLENT RESULTS
T. Nuver1 , D. Kramer1 , V. Althof1 , R. Westendorp1 , A. Minken1
1
RISO, Deventer, Netherlands
Purpose: To verify the delivered dose for prostate patients Tomotherapy
HI-ART treatments using dose reconstruction based on the integrated MVCTdetector.
Materials: In this study, a dose-verification software tool, supplied by Tomotherapy, was used to compare reconstructed delivered dose with theplanned dose. Two groups of prostate patients were selected. For the firstgroup of 10 patients (April 2009 to Feb. 2010) all fractions delivered on oneof our two Tomotherapy HI-ART machines were considered (206 fractions).
For the second group of 12 patients (Sept. and Oct. 2010) only the firsttreatment fraction was considered. Different treatment fractionation schedules were used: fraction dose varied from 2.0 to 2.9 Gy. Treatment plans weregenerated on Tomotherapy Hi-Art Planning Software V3.1.4. All patients werepositioned based on daily, on-line MVCT scans using implanted gold markers. The detector signals were attenuation corrected based on the MVCT
scan to reconstruct the incoming fluence. This fluence was then re-projectedon the MVCT scan to calculate delivered dose. The planned dose distribution was subtracted from the reconstructed distribution, and histograms wereconstructed from the differences. Only voxels with a dose larger than 30% of
the fraction dose were considered.
Results: For the first group of patients, for all fractions, the errors were
smaller than ±5% of the prescribed dose. For 90% of the fractions the errors were smaller than ±4%. A target change in October 2009 resulted in asignificant change (3%) in the calculated dose differences, which appeared
to be related to changes in the grey values of the MVCT scan. For the second group, for which the MVCT grey values were monitored and adjusted
more strictly, the errors were smaller than ±3% of the prescribed dose. The
largest dose differences were seen for patients with large variations in theamount of gas in their rectum. Dose differences due to small artefacts in the
MVCT scans were seen in a period of one week, caused by wrong MVCT
calibration.
Conclusions: Dose reconstruction based on MVCT detector data yields excellent agreement with the planned dose distribution for prostate patients. Accurate quality assurance on the Tomotherapy HI-ART MVCT is fundamental
to obtain optimal dose reconstruction accuracy. With the further development

Figure 1. Results of the measurements. Definitions of the angular scale.a)
The charges of the diodes are accumulated during 1 min and then normalized
to some arbitrary value.b) Schematic cross-section of the IN-VIVO catheter;
definition of the angular scale: for the null angle (φ=0) is chosen direction,
which is parallel to the plates of the detectors. c) Fluoroscopic images of"source-eye view" of the IN-VIVO probe for two orientations: φ=0 and φ=90.
Conclusions: Performed measurements provide useful ideas for calibration
technique and clinical use of rectal IN-VIVO probe.Firstly, the angular response of the detectors is sharp for the angles close to 0 and 180. Therefore it
is reasonable to perform the long-term reproducibility calibration of the detectors for angular ranges 50 110 or 240 300.Secondly, after the brachytherapy
treatment of gynecological patient is finished and the IN-VIVO measurements
for this treatment are done, the final angular correction for diodes readings
should be applied. The angle φ detector to radiation source can be estimated from the fluoroscopic images (AP, anteriorposterior, or LAT, lateral)quite precisely, ± 10.At present we are introducing this technique into clinicalFig. 1: In the top row, SOS map, and non-corrected simulation and treatment
US images. In the bottom row, shift map, and comparison between corrected
and non-corrected USref and UStrt images for one of the prostate cancer
patients.
Results: Significant shifts (up to 4 mm) are present in the corrected US images. The shifts map derived from the simulation CT scan affects the USref
and UStrt images differently (Fig. 1) the same way as SOS aberrations affectalong different paths due to the different tissue distributions non corrected US
images.
Conclusions: Significant SOS corrections were found, especially for patientswhere large changes occurred between simulation and treatment stages.
This error has probably affected several previous US-CT studies reported in
the literature: the corrections improve accuracy in direct USCT comparisons
but also yield an improved image quality (reducing defocusing and geometricdistortion) and more accurate outline of regions of interest. Other sites (gynaecological, head and neck) are likely to benefit from the SOS correction.

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A NOVEL METHOD FOR MEGAVOLTAGE SCATTER CORRECTION
IN CONE-BEAM CT ACQUIRED CONCURRENT WITH ROTATIONALIRRADIATION
M. van Herk1 , J. J. Sonke1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation therapy , Amsterdam, Netherlands

AUTOMATIC BLADDER SEGMENTATION ON CBCT FOR ONLINEART OF BLADDER CANCER
X. Chai1 , M. van Herk2 , J. Van de Kamer2 , M. Hulshof1 , P. Remeijer2 , A.
Bel1
1
ACADEMIC M EDICAL C ENTER, Radiation Oncology Department, Amsterdam, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology Department, Amsterdam, Netherlands

A NOVEL CT-BASED CONTRAST ENHANCEMENT TECHNIQUE FOR
MARKERLESS LUNG TUMOR TRACKING IN X-RAY PROJECTION
IMAGES
A. Fassi1 , J. Schaerer2 , M. Riboldi1 , D. Sarrut2 , G. Baroni1
1
P OLITECNICO DI M ILANO U NIVERSITY, Bioengineering, Milano, Italy
2
U NIVERSITÉ DE LYON ; CREATIS ; CNRS UMR5220 ; C ENTRE L ÉON
B ÉRARD, Lyon, France

Purpose: Acquisition of cone-beam CT (CBCT) concurrent with rotational irradiation techniques such as VMAT allows efficient data collection for off-line
decision protocols, validation of the patient geometry during actual therapy
and detection of intra-fraction motion. Unfortunately, lateral scatter of themegavoltage (MV) beam unto the kilovoltage (kV) detector has a considerable impact on CBCT image quality as substantial amounts reach the kV
detector. The MV scatter depends on patient geometry, dose rate and fieldshape . Our purpose is to develop a MV-scatter correction scheme that does
not require knowledge of these data. One method would be to alternate MV
and kV acquisition. However, since one aims at minimal MV delivery times,
interruption of the MV irradiation is not preferred.
Materials: The kV source is pulsed only for even frames, while odd frames
are acquired without kV pulse. In this way, subsequent images measure kVdata with MV scatter, and MV scatter only. In principle it is then trivial tosubtract the MV scatter (odd frames) from the even frames to eliminate the
MV scatter profile (doubling MV scatter quantum noise). Our procedure ismore extensive to reject the significant amount of non-linear ghosting in theodd frames as well as MV quantum noise therein. In the novel method, scatter, noise and artifacts in the odd frames are separated based on their spatial and temporal frequency characteristics and subsequently subtracted fromthe even frames. The method was tested on a CatPhan 600 scanned on an
Elekta Synergy system (version 4.5, 120 kV, 20 mA, 20 ms, 860 acquired
frames) simultaneously with delivery of a typical arc of one of our SBRT patients (one out of two arcs, 9 Gy delivered dose per arc). After correction for
MV scatter, regular reconstruction was applied.
Results: Without correction, acquisition during VMAT leads to significant cupping (Fig. 1b) as the MV scatter has similar intensity as the attenuated kV
signal. Straightforward subtraction of even and odd frames introduces subtantial artifacts due to non-linear ghosting (Fig. 1c). Our proposed method
totally corrects the MV scatter (Fig. 1d). Compared to acquisition without MV
beam (Fig. 1a), the reconstruction quality is identical except for the unavoidable addition of noise due to the scattered MV radiation in the even frames.
The reduced effective frame rate still allows a sufficient number of images
to be collected as VMAT delivery times generally exceed CBCT scan times.
Correction is performed in-line with acquisition without introducing delays.

Conclusions: We developed a novel method to correct for MV scatter reaching the kV chain during concurrent acquisition of CBCT scans with rotational
radiotherapy that does not require prior knowledge of the MV delivery sequence or the patient shape. The method was tested on phantoms. It will bevalidated during patient irradiation in the near future.

Purpose: In online adaptive radiotherapy (ART) strategies of bladder cancer,
plans with different bladder volumes are created based on images acquired
early during treatment. Subsequently, the smallest plan covering the bladderon CBCT is selected as the plan of the day. The aim of this study is to develop
an automatic bladder segmentation approach, and test this approach to selectthe appropriate plan from the library of plans for an ART procedure.
Materials: 7 bladder cancer patients with a planning CT and about 16 CBCT
scans were included in our study. For each patient, all CBCT scans werematched to the planning CT using bony anatomy. The bladder contours weremanually delineated for each CT (as reference) and CBCT (for model building and validation). The automatic segmentation method consisted of two
steps: first a bladder deformation model was built from the training data (theplanning CT and first 5 CBCT scans) and then the model was applied toautomatically segment bladders in the test data (the remaining CBCT scans).
Principle component analysis (PCA) was applied to the training data to model
patient-specific bladder deformation pattern. PCA is a method from multivariate statistics, which quantitatively determines the most important modes ofcorrelated motion of the training data. The number of PCA modes was chosen such that 95% of the total shape variation was described. The automatic
segmentation started from the mean bladder shape, which was adjusted bychanging the weight of each PCA mode. As a result, the segmentation contour was deformed consistently with the training set to fit the bladder in test
image. A cost function was defined by the cross correlation between the gradient field of a planning CT sampled on its corresponding bladder contour
and the gradient field of a test CBCT sampled on the contour candidate. The
cost function measured the goodness of fit of the segmentation on the test
image. The segmentation was obtained by minimizing this cost function using a simplex optimizer (Figure 1). Volume and distance based metrics andthe accuracy of plan selection were evaluated to quantify the performance.

Results: For all 7 patients, only 3 PCA modes were needed to represent 95%of the bladder shape variation. The automatically segmented outlines had agood agreement with the manual delineation (overlap from 0.78 to 0.92, mean
overlap is 0.86). The mean and SD of the local residual error averaged overall patients were 3.6 mm and 2.6 mm, respectively. The agreement of plan
selection between automatic and manual bladder segmentation was 87%.
Conclusions: PCA is an efficient method to describe patient-specific bladderdeformation. The statistical shape based segmentation approach is robust
to the relatively poor CBCT image quality and allows reliable automatic segmentation of the bladder on CBCT. This method is suitable to more objectively
select the appropriate plan for online ART of bladder cancer.

Purpose: Direct lung tumor tracking using in-room X-ray imaging systems,
such as digital radiography or rotational cone-beam CT, provides valuable
information for IGRT applications. The superimposition of surrounding radioopaque structures may however result in poor lesion contrast. The aim of
this study is to develop and investigate a novel automatic method for contrast
enhancement and robust markerless tracking of lung tumors in X-ray images,
exploiting anatomical information derived from CT volumes.
Materials: The implemented technique was tested on 10 lung cancer patientstreated with stereotactic body frame based radiation therapy. Data collected
for each patient include 4D CT images acquired using a Philips Brilliance CT
scanner and CBCT acquisitions performed with the Elekta Synergy systemfor patient setup.CT-based contrast enhancement: Lung regions including thetumor are masked in the 4D CT maximum intensity projection (MIP), applying threshold-based segmentation algorithms. Digital reconstructed radiographs (DRRs) are generated from the resulting image, following rigid registration with the reconstructed CBCT volume. Contrast-enhanced tumor ROIs
are obtained by subtracting the generated DRRs to the original cone-beam
images at corresponding projection angles, after ROI histogram equalization.Tumor tracking: Target identification on enhanced CBCT projections isrealized through robust template matching techniques. Reference templates
for each cone-beam image are obtained by projecting at different angles thegross tumor volume (GTV) delineated on the reference 4D CT 50% phase image. The position of the projected GTV centroid is identified on CBCT images
performing fast normalized cross correlation in the frequency domain.
Results: The developed tracking method was evaluated on 10 cone-beamacquisitions (1 for each patient), including about 650 two-dimensional projections provided over a full 360◦ gantry rotation. The rate of target identificationin contrast enhanced CBCT images proved to be on average 34% (±6%)
higher than in original projections adjusted for intensity. In case of tumor
recognition achieved with and without enhancement, the cross-correlation coefficients with the reference templates increased by 11% (±4%) when thecontrast enhancement technique was applied. Exemplifying results for threeselected studies are reported in figure 1, showing the capability of the proposed method in increasing tumor region visibility and reducing the overlap
effect of the surrounding anatomical structures, such as the spine or the rib
cage.

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Conclusions: A method for contrast enhancement and robust markerless
tracking of lung tumors in X-ray projections is proposed. The developed technique can be applied to improve robust trajectory estimation of moving targets
from CBCT projections for intra-fraction motion compensation and to increase
the clinical application of image guidance techniques in lung cancer patients
based on markerless 2-D X-ray imaging.
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ADAPTIVE RADIOTHERAPY TREATMENT FOR PATIENTS WITH
ATELECTASIS BASED ON PORTAL DOSIMETRY AND REPEATEDCONEBEAM CT
L. Persoon1 , M. Öllers1 , S. Wanders1 , D. De Ruysscher1 , D. Tissen1 , J.
Wouters1 , F. Verhaegen1 , S. Nijsten1
1

D EPARTMENT OF R ADIATION O NCOLOGY (MAASTRO), GROW –S CHOOL FOR O NCOLOGY AND D EVELOPMENTAL B IOLOGY, M AASTRICHTU NIVERSITY M EDICAL C ENTRE, Maastricht, Netherlands

Purpose: The amount of atelectasis (lung fluid) in lung cancer patients canchange during the course of treatment and may displace tumors or healthy
tissue. Consequently, the delivered dose to these patients can be different
from the planned dose. To ensure that the correct dose was delivered and to
be able to adapt a planned treatment to changes in anatomy, dose verification
during treatment is essential. In this study, we describe the implementationof an adaptive clinical protocol for lung cancer patients with atelectasis and amethod to determine decision parameters.
Materials: An adaptive protocol using weekly conebeam CT (CBCT) scans
and 2D portal dosimetry was implemented. In the protocol, a treatment
was adapted when either large anatomical changes were visible on CBCT
(changes in target positioning >7 mm) or significant dose deviations were detected using 2D portal dosimetry. A dose deviation was classified when for
all beams of a treatment fraction >5% of the pixels showed a gamma value(γ ) >1, using gamma criteria of 3%, 3mm. In case of re-planning a second
CT was acquired. The dose-volume-histograms (DVHs) for the non-adapted
scenario were compared to three adaptive scenarios, which involved doserecalculation and/or re-planning in the second CT. The DVHs were calculatedusing deformable registration based on demons to accumulate the dose of
the different plans on the initially planned patient anatomy and delineations.
For this study, we analyzed 6 patients included in the adaptive protocol.
Results: From the 6 evaluated patients, 2 patients got a treatment adaptation
based on 2D portal dose differences and 2 patients showed target displacements on the CBCT of more than 7 mm, also leading to an adaptation of thetreatment. Fig. 1a shows a dose deviation starting to emerge from fraction
11. After fraction 21 a new plan was used for treatment and dose errors diminished considerably. The DVHs showed (Fig. 1b) that when no adaptation
was performed the lung dose would have been higher than originally planned.

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patient is irradiated with the non-coplanar treatment plan that was based on
the planning CT-scan (current clinical protocol). In the second strategy, prior
to irradiation the fluence profiles of the treatment beams were re-optimized
based on the daily CT scan (beam angles remained the same as for the planning scan). In the last strategy, for each fraction a completely new plan (beamangles and profiles) was generated based on the daily CT-scan. Non-rigid
registration and LQ-corrections were used to obtain cumulative dose distributions.
Results: In 50% of the patients, constraint violations occurred for the repeated plan when we look at the dose distributions of the single fractions. For
33% of those patients, severe constraint violations in a single fraction even resulted in constraint violations in the integral dose distribution , i.e. in one case
11 Gy was delivered to an OAR with a constraint of 5 Gy. In those cases, thebeamweight plan and adaptive plan were easily capable of taking those OAR
deformations into account and both methods designed good treatment plans
without constraint violations. In one patient the prescribed dose to the PTV,
that was limited because of OAR constraint violations, could be increased by
the two re-optimization methods. The adaptive plan performed slightly better
than the beamweight plan, but the latter requires only some minutes computation time while full re-optimization would take a few hours.
Conclusions: Adaptive re-optimization of fluence profiles based on daily
CT scans can significantly improve dose distributions in liver SBRT. Reoptimization of both beam angles and beam profiles gives little extra gain.

536 oral
RTOG 9601: SALVAGE RT & ANTI-ANDROGEN THERAPY IN
PROSTATE CANCER PATIENTS WITH ELEVATED PSA AFTER
SURGERY
W. U. Shipley1 , D. Hunt2 , H. Lukka3 , N. Heney1 , P. Major3 , D. Grignon4 , M.
Patel3 , J. P. Bahary5 , C. Lawton6 , H. Sandler7
1
M ASSACHUSETTS G ENERAL H OSPITAL, Department of Radiation Oncology, Boston, MA, USA
2
RTOG S TATISTICAL C ENTER, Philadelphia, PA, USA
3
J URAVINSKI C ANCER C ENTER, Hamilton, Canada
4
I NDIANA U NIVERSITY S CHOOL OF M EDICINE, Indianapolis, USA
5
CHUM - C AMPUS N OTRE -DAME, Montréal, Canada
6
M EDICAL C OLLEGE OF W ISCONSIN, Milwaukee, USA
7
S AMUEL O SCHIN C OMPREHENSIVE C ANCER I NSTITUTE, Los Angeles,
USA

TRACKING LATENCY IN KV IMAGE-BASED DYNAMIC MLC TRACKING WITH DIRECT IMAGE ACCESS
W. Fledelius1 , P. J. Keall2 , B. Cho3 , X. Yang4 , D. Morf4 , S. Scheib5 , P. R.
Poulsen1
1
A ARHUS U NIVERSITY H OSPITAL, Oncology, Aarhus C, Denmark
2
S YDNEY M EDICAL S CHOOL , U NIVERSITY OF S YDNEY, Sidney, Australia
3
A SAN M EDICAL C ENTER, Seoul, Korea Republic of
4
VARIAN M EDICAL S YSTEMS, Imaging Laboratory GmbH
5
VARIAN M EDICAL S YSTEMS I NTERNATIONAL AG, Baden-Daettwil,
Switzerland

Conclusions: We have implemented an adaptive treatment protocol in dailyclinical practice based on repeated CBCT scans and 2D portal dosimetry.
Patients are monitored during treatment to support decision making for adaptation. At this moment we use decision criteria for treatment adaptation basedon portal dosimetry, however, further optimization is necessary to better predict changes in a DVH. We have shown that it is feasible to acquire DVHs
during treatment for comparison of different scenarios. By optimizing the decision parameters it should be possible to prevent either over or under dosageof the tumor or OARs.
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ADAPTIVE LIVER SBRT: DAILY RE-PLANNING TO COMPENSATEFOR NON-RIGID ANATOMY CHANGES IMPROVES DOSE DISTRIBUTIONS
S. Leinders1 , Y. Seppenwoolde1 , S. Breedveld1 , E. Vásquez Osorio1 , A.
Mendez Romero1 , B. Heijmen1
E RASMUS M EDICAL C ENTER R OTTERDAM, Rotterdam, Netherlands

1

Purpose: In stereotactic body radiotherapy (SBRT) of liver tumors, daily image guidance based on contrast enhanced CT-scans enables precise deliveryof high tumor doses with small margins (Mez Romero et al. IJROBP 2010).
In this paper we also demonstrated that the daily tumor set-up corrections
were not always effective in avoiding OAR dose constraint violations caused
by non-rigid patient anatomy changes. Dose to a surrounding organ at risk
(OAR) could even increase in case of an isocenter shift in the direction of
the OAR. In this study we evaluated the impact of daily re-planning based on
acquired contrast-enhanced CT-scans to compensate for non-rigid anatomychanges.
Materials: For eight patients with twelve tumors in different liver regions,
three different planning strategies were simulated. All plans were generatedusing iCycle, a novel in-house developed algorithm for integrated beam angle and profile optimization (Breedveld et al. PMB 2006&7). Total dose wasdelivered in three fractions (clinical protocol). In all strategies, the patient was
shifted each fraction to correct for the tumor displacement derived from registration of the daily CT-scan with the planning scan. In the first strategy, theS 219

RTT Proffered Papers 5: Patient Care

535 oralPurpose: Target tracking is a promising method for motion compensation inradiotherapy. All tracking systems have latency, i.e. a time lag between thetarget motion and the correcting beam-target re-alignment. For image-based
dynamic multileaf collimator (DMLC) tracking, latency has been shown to be
the main contributor to geometrical errors in tracking of respiratory motion.
The reported latency was mainly due to slow transferring of image data fromthe image acquisition system to the tracking system via image file storage ona hard disk. The purpose of the current study was to integrate direct image
access with a DMLC tracking system and to quantify the tracking latency of
the integrated system.
Materials: A DMLC tracking system integrated with a linear accelerator wasused for tracking of a motion phantom with an embedded marker during delivery of a 6 MV field with circular MLC aperture. The motion stage performeda sinusoidal motion parallel to the MLC leaves. The peak-to-peak motion amplitude was 20 mm and the period length was 4-8.5 seconds. Fluoroscopic
kV images were acquired perpendicular to the treatment beam with an OnBoard Imager system. The kV images were transferred directly to a computer
program that segmented the marker and sent the projected pixel position to
the DMLC tracking program. This program estimated the 3D marker position
and refitted the MLC aperture to the marker. DMLC tracking was performed
with kV imaging intervals dTimage of 66.7 ms, 100 ms, 133 ms, 150 ms, 200
ms, 500 ms, and 1000 ms (15 Hz to 1 Hz). Continuous MV images wereacquired during the treatment delivery. Offline, the motion of the marker andthe MLC aperture center were extracted from the MV images and fitted tosinusoidal functions. The tracking system latency was determined from thephase shift between marker motion and MLC motion. The combined latency
contribution from image acquisition and image transfer to the marker segmentation program was calculated by subtraction of all other latency contributions.
The results were compared to kV image based DMLC tracking without direct
image access (i.e. with image transfer via image file storing on the hard disk).
Results: Fig. 1 (top) shows the tracking latency with and without direct image
access. The latency is shown as function of the imaging interval dTimage.
With direct image access the tracking latency was 159ms + 0.56 * dTimage,which was a substantial improvement compared to tracking based on image
file writing. As an example the tracking latency was reduced from 550 ms
to 265 ms for 5 Hz imaging. The combined latency contribution from image
acquisition and image transfer was 124 ms (±9 ms, 1 standard deviation)
independent on dTimage ( Fig. 1, bottom).

P ROFFERED PAPER

Conclusions: kV image based DMLC tracking with direct image access was
successfully implemented, resulting in large reductions of the tracking latency.
It should allow for more accurate tracking. Work will follow on direct image
access for MV image based DMLC tracking.

Purpose: To test by a Phase III trial, if anti-androgen therapy (AAT), whencombined with Radiation Therapy (RT), will improve further the cancer control
outcomes as well as overall survival in this subgroup of patients with elevated
PSA levels after radical prostatectomy (RP).
Materials: RP patients with pT3, N0 or with pT2, N0 (and also positive margins) who have an elevated PSA were entered on a double-blinded, placebocontrolled trial of RT alone (64.8 Gy in 36 fractions of 1.8 Gy) Vs RT plus AAT(24 months of bicalutamide, 150mg QD) during and after RT. The primary
end-point is overall survival.
Results: From 3/98 to 3/03, 771 eligible patients (median age 65) were randomized to RT plus AAT (387) or RT alone (383). 252 patients (33%) were
pT2, N0 and 518 patients (67%) were pT3, N0. 672 patients (87%) had a PSA
nadir after RP of < 0.5 ng/ml. 655 patients (85%) had an entry PSA value of<1.6, 115 patients (15%) had an entry PSA of 1.6-3.9. Median follow up is 7.1
years. The actuarial overall survival at 7 years is 91% for RT plus AAT and
86% for RT alone. Too few "primary end-point events" have occurred as yet toallow a statistical comparison between these groups. PSA progression was
defined as a PSA > 0.4 ng/ml in patients whose protocol treatment resulted
in an undetectable PSA or, if not, when the PSA rose 0.3 ng/ml above theentry PSA. Freedom From PSA Progression (FFP) at 7 years is 57% for RT
plus AAT and 40% for RT alone (P < 0.0001); for 226 patients with GS < 6
are 63% and 50% (P<0.02): for 411 GS 7 are 55% and 39% (P<0.0006), andfor 134 GS 8-10 are 56% and 26% ( P < 0.0008). The cumulative incidenceof metastatic PC at 7 years is in the RT & AAT arm, 7.4% ( 25 patients),Vs
12.6% (46 patients) in the RT & placebo arm (p<0.041).Late Grade 3 and
4 GU, GI and cardiac toxicity were similar in the bicalutamide and placeboarms. Gynecomastia differed significantly, 89% and 15%. In the RT plus AAT
arm Grade 3 was the highest liver toxicity observed which occurred in 3 of387 patients.
Conclusions: The addition of 24 months of peripheral androgen blockade(AAT) during and after RT significantly improved FFP and reduced the incidence of metastatic PC without adding significantly to radiation toxicity. The
significance of the benefit in overall survival, as well analysis of risk-stratified
subsets, awaits longer follow up.
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A SOCIETY AND COLLEGE OF RADIOGRAPHERS UK SURVEY OF
RADIOTHERAPY SKIN CARE
R. Harris1
1
T HE S OCIETY AND T HE C OLLEGE OF R ADIOGRAPHERS, London, United
Kingdom
Purpose: The primary objective of the survey was to evaluate skin care practice at radiotherapy centres across the United Kingdom. The results will be
used to review guidelines issued by The Society and College of Radiographers.
Materials: A link to an on-line survey, using the Survey Monkey™ tool, wase-mailed to all radiotherapy centre managers in the United Kingdom (N = 67)
and they were invited to provide one response per department. 54 centres
responded within the allocated timeframe with a final response rate of 81 %.
Results: Key results:
Guidelines and Assessment prior to radiotherapy
46 centres had skin care guidelines for staff.
30 centres do not use a skin assessment tool.
The RTOG skin assessment tool1 is used by 20 centres.
Despite papers emphasising potential risk factors2 36 respondents reported
no formal documentation.Prophylactic skin care
Despite a lack of evidence to support prophylactic use of any specificproduct.3
1. 26 centres recommend an aqueous cream.

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2. 5 recommend an Aloe vera product.
Evidence indicates that gentle skin and hair washing should be unrestricted
for patients and there should be no restriction to using a specific type ofsoap.4
1. 42 centres specify the type of soap to use: ’simple®’, ’dove®’ or ’none’
being the most common answers.
2. 9 specify the type of deodorant to use: ’none’ or ’Pitrok®’ being themost common answers. Some departments are still saying ’no deodorant’ despite updated evidence.5
Main products used during treatment:
Erythema
1. 49 aqueous cream
2. 8 Aloe vera
3. 7 Diprobase®
Dry Desquamation
1. 35 aqueous cream
2. 24 hydrocortisone 1 % - despite contradictory evidence6
Moist desquamation
1. 33 hydrogels
2. 21 silicone dressing i.e. Mepitel®
3. 18 hydrocolloids
Lanolin and gentian violet are still in use, despite the evidence to contraindicate this practice.7
Of those undertaking care of moist desquamation 29 centres have staff withadditional training in wound care management.
Conclusions: The type of regime applied preventatively and to erythema appears to have no influence.2 It would seem that topical agents are unlikely
to realistically affect skin reactions from occurring and perhaps we should befocussing on symptomatic comfort of our patients.8
Variation in product utilisation could be reduced if evidence based recommendations were adopted. References:
1. Cox, J. et al. (1995). Toxicity criteria of the Radiation Therapy Oncology Group (RTOG) and the European Organisation for Research andTreatment of Cancer (EORTC). Int J Rad Onc Biology Physics 31 (5):1341-1346
2. Russell, N. et al. (1994). Quantification of patient to patient variation ofskin erythema developing as a response to radiotherapy. Radiotherapy
and Oncology 30 (3): 213-221
3. Wells, M. et al. (2004). Does aqueous or sucralfate cream affect theseverity of erythematous radiation skin reactions? A randomised controlled trial. Radiotherapy and Oncology 73 (2): 153-162
4. Bolderston, A. et al. (2006). The prevention and management of acuteskin reactions related to radiation therapy: a systematic review andpractice guideline. Supportive Care in Cancer 14 (6): 802-817
5. Theberge, V. et al. (2009). Use of axillary deodorant and effect onacute skin toxicity during radiotherapy for breast cancer: a prospective
randomised noninferiority trial. Int J Rad Onc Biology Physics 75 (4):1048-105
6. Sperduti, A. et al. (2006). A feasibility study of an internal control
methodology using hydrocortisone cream for the management of skinreactions in patients receiving radical radiation therapy for cancers of
the head and neck. Journal of Radiotherapy in Practice 5: 211-218.
7. Gollins, S. et al. (2008). RCT on gentian violet versus a hydrogel
dressing for radiotherapy-induced moist skin desquamation. J Wound
Care 17 (6): 268-70, 272, 274-5
8. Gosselin, T. et al (2010). A prospective randomized, placebocontrolled skin care study in women diagnosed with breast cancer undergoing radiation therapy. Oncol Nurs Forum 37 (5): 619-626

W EDNESDAY, M AY 11, 2011
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BREASTCANCERPATIENTS’KNOWLEDGE
BASE
OF
RADIOTHERAPY- DEVELOPING AN E-KNOWLEDGE TEST
1
2
3
M. Siekkinen , A. Ryhanen , S. Pyrhonen
1
T URKU U NIVERSITY H OSPITAL, Department of Radiotherapy, Turku,
Finland2
T URKU C ITY H OSPITAL, Department of Internal Diseases, Turku, Finland
3
T URKU U NIVERSITY H OSPITAL, Department of Nursing Science, Turku,
FinlandPurpose: Patient education is an essential part of a radiotherapy (RT) period
because of its psychosocial and physical side effects. Knowledge of RT has
positive effect on side-effects and quality of life of breast cancer. Radiotherapists should obtain objective evidence of patients’ knowledge of radiotherapy
and provide patient education according to their needs. The test can be aneffective instrument to measure and do the diagnosis of the knowledge base.
The purpose is to develop an e-knowledge test to analyze breast cancer patients’ knowledge of radiotherapy at the beginning of treatment (e-RTKT-BC).
The ultimate goal is to improve the empowering patient education in radiotherapy.
Materials: Systematic literature review of the knowledge needs of breast cancer patients relating to RT was done. The knowledge needs were examinedwith the empowering knowledge as a framework. The content validity wasdetermined. Two panels; a sample of six professionals of Turku university
hospital in cancer policlinic and RT and a sample of five breast cancer patients of support group in South-Western cancer society, were asked to readeach item and respond to three questions of intelligibility and consistency.
The face validity and adequacy of the knowledge test was measured by apilot study of ten breast cancer patients at the beginning of their radiotherapy.
Results: The final version of the e-RTKT-BC consisted of 24 items of radiotherapy based on the literature review. The searches in CINAHL (19822010)
and MEDLINE (19502010) and hand searching undertaken in February 2010
according to PRISMA statement included six papers. The literature showsthat the most frequently cited category of knowledge needs were biophysiological and functional category, social and financial categories were cited only
once, and ethical and the experiential and ethical categories were cited not atall. The essential concepts concerning "RT process", "possible side-effects","side-effects and self-care" and "daily life and RT", were composed to measurable form according to the used variables. The items were true or false
items; correct answer yielded one point, no points of incorrect answer.
Conclusions: The e-RTKT-BC should be used to measure breast cancer
patients’ knowledge base of radiotherapy. Further developing is needed. Inorder to determine the reliability of the e-RTKT-BC further research should
be focused on testing it in radiotherapy and evaluated in terms of reliability.
The empowering effect of patient education according to knowledge basediagnosis should also be studied.
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EVALUATING THE EFFECT OF CAPHOSOL IN REDUCING ORALMUCOSITIS IN HEAD AND NECK CANCER PATIENTS UNDERGOING CHEMORADIOTHERAPY OR RADIOTHERAPY
M. Thomson1
1
B EATSON O NCOLOGY C ENTRE W ESTERN I NFIRMARY, Glasgow, United
Kingdom
Purpose: The purpose of this study was to evaluate the implementation of
Caphosol in the prevention and treatment of mucositis in patients undergoingRadiotherapy or Chemo-radiotherapy whose treatment fields included a largepart of the oral cavity. compared to the previous standard treatment.
Materials: 60 patients undergoing whole mouth irradiation for oral andoropharynx cancers over a 6 month period in 2010 were included in theassessment. Patients suitable for inclusion in the study were selected bya consultant radiographer. A retrospective review of 30 patients who hadcompleted radiotherapy receiving the standard treatment were compared to
30 patients who had received Caphosol mouthwash.Patients were treatedaccording to the following regimen: 36 patients: 68Gy in 34 fractions; 24 patients: 66Gy in 33 fractions;All patients were instructed to rinse with Caphosol
4 times daily from the start of radiotherapy until radiation therapy was completed. Caphosol was prescribed on a weekly basis so that compliance tostudy medication could be assessed.Patients were monitored through weekly
clinic assessment for: Grade of oral mucositis - using the CTC/EORTC/RTOG
assessment scale (range 0-4); Weight change; Performance status - assessed using the WHO Scale (range 0-4); Oral intake - assessed using the
BWoSCC scale (range 0-4); Pain - using the WHO Pain Ladder which includes a patient self-assessment
Results: The results from the statistical analysis showed statistical significance in Oral Mucositis (OM)grade and in analgesic steps. OM grade showedstatistical significance for weeks 3,4,5,6 and 7 with a p values of 0.004 forweek3, p=0 for week4, p=0 for week 5 and p=0 for week 6. Week 7 had adifferent sample size N=17 for Caphosol and N=12 for Corsodyl. Week 7 had
a p value of 0. The median for Caphosol was lower in each of these weeks
which showed Caphosol improved OM grade.Results for the analgesic steps

W EDNESDAY, M AY 11, 2011were similar. Week 1,2,and 3 showed no statistical significance and week 4,
5, 6 and 7 all showed a significant diference between the two mouthwashes.
P value for week4 was 0, week 5 p=0.001 and week 6 p=0.001. Again week 7
had a different sample size but showed a statistical difference with a p valueof 0.003.The results for oral intake showed no statistically significant difference between the mouthwashes for weeks 1 and 2. Week,3 4, 5, and 6 all
showed statistically significant differnece with p values of 0.004 for week3,
p=0.32 for week4, p=0.01 for week 5 and p=0.02 for week 6. This shows thatpatients using Caphosol can eat more orally during treatment.
Conclusions: Positive: Results encouraging with statistical significance inthe reduction of overall grade of OM and the reduction in the use of analgesia.Caphosol worthy of further investigation in the weeks immediately prior tocompletion of radiotherapy treatment in the area of head and neck cancers
Results consistent with previously published studies in head and neck cancer
and other therapy areasLimitations : mucositis graded by members of MDT
so possibility of inconsistency in grading limited to 4 rinses per day only noadvice to increase in line with symptoms as per product information whichstates can increase to 10 per day
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PATIENT GROUP DIRECTIONS: FACILITATING EFFICIENT RADIOTHERAPY SERVICE AND PATIENT CARE
G. Hill1
1
T HE C HRISTIE, Radiotherapy Department, Manchester, United Kingdom
Purpose: The Christie at Oldham commenced treating patients in March
2010, from the onset radiographers took on additional responsibilities andwere given advanced training to facilitate patient care in a satellite environment. Patient Group Directives (PGDs) were seen as imperative in this aim
to provide a more efficient and effective service. PGDs allow the supply or
administration of medicines to groups of patients who may not be individually
identified before presentation for treatment1 . The HSC 2000/0262 details the
exemption of sections 52 and 53 of the Medicines Act 19683 thus allowing
PGDs. The Allied health professions (AHP) prescribing and medicines supply mechanisms scoping report recommends expanding AHP access to themechanisms to supply prescription only medications4 .
Materials: All radiographers with over 2 years experience were required tocomplete competencies allowing them to dispense items most commonlyused in radiotherapy; this can be achieved without a prescription or clinician
involvement and is provided at the point of treatment delivery. Strict trust
policy5 for training of radiographers PGDs includes a period of supervised
dispensing, verbal examination by an appropriately trained radiographer andonce deemed competent the PGD was signed.
Results: PGD’s can be dispensed at the time of treatment by radiographers
without impacting on service. The average wait for dispensing is 5 minutes
and there is no need for clinician involvement or prescription. In comparison the average time for review is 36 minutes with an additional 30 minutes
in pharmacy. Approximately 171 items have been dispensed under PGDs
on the treatment units in Oldham over a period of 5 months to 161 patients.
These results indicate an average saving of 4.37 weeks of waiting and consultation time within the 5 month period based on a 37.5 hour week. There
were 5 prescriptions for PGD medications written by the clinician based at thesatellite during the same time period.
Conclusions: The benefits to implementing PGDs within the workforce would
appear obvious. The results demonstrated that PGD Radiographers reduce
patient waiting times and the burden on review clinics and pharmacy, thus
improving patient experience and efficiency of the service5 . Radiographersmonitor patient reactions daily and give more appropriate advice to patients
regarding medications under the PGDs; this expands the radiographer’s current role and thus will improve morale and retention7 .
541 oral
HEALTH STATUS EVALUATION OF CHILDREN WITH BRAIN TUMORS WHO WERE TREATED BY CRANIOSPINAL IRRADIATION
A. Sengul1 , S. Kamer1 , Y. Anacak1
1

E GE U NIVERSITY, Department of Radiation Oncology, Izmir, Turkey

Purpose: To determine the growth, endocrinologic, neurocogtive and odiologic late term side effects profiles in survivors of pediatric medulloblastoma
patients treated by craniospinal irradiation.
Materials: 28 survivors of pediatric medulloblastoma patients treated bycraniospinal irradiation were participated in this study. Craniospinal radiation dose of 7 patients was between 23,4 and 24 Gy and the rest received
between 35,2 and 36 Gy. Total tumor bed dose was between 53,2 and 59,4
Gy. Height, weight and body mass index (BMI) at the time of treatment wererecorded from archive records. Patients were invited to the clinic and lastvalues of height, weight, BMI, sitting height and head circumference were
calculated. Puberty examination was performed and odiologic tests were applied. Cognitive functions were evaluated by Raven’s Standard Progressive
Matrices (RSPM). Free T3, T4 and thyroid stimulating hormone (TSH) values
were assessed from blood.

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Results: The mean standard deviation score (SDS) of height at the time oftreatment was 0,1±1,3 while it was -1,8 ± 1,4 after treatment. At the lastevaluation, mean height SDS was significantly less then normal population
at the same age. Loss in weight after the treatment was observed. SDS of
BMI was significantly lower after treatment because of the serious decreasein height and little decrease in weight. Sitting height of the patients who received high dose of craniospinal irradiation was significantly lower than the
low-dose group. Mean head circumference was -1,6 ± 1,3. 7 % of patients
had delayed puberty. Hypothyroidism was detected in % 58. From the patients who underwent odiologic tests, % 79 had any degree of loss of hearing
at any ear. % 39 had grade 3 or 4 ototoxicity. Patients age less than 7 hadhigher risk of ototoxicity (p=0,043). The mean percentile of RSPM test results
was 32 ± 26 while it was 50 percentil for Turkish poopulation.
Conclusions: Serious adverse effects occur because of the treatment in survivors of pediatric medulloblastoma. Patients should be evaluated by a teamincluding radiation oncologist, pediatric oncologist, endocrinologist and psychiatrist regularly after treatment.
542 oral
CLINICAL IMPLEMENTATION OF A PROTOCOL FOR PATIENTSCARRYING A PACEMAKER OR ICD RECEIVING RADIOTHERAPY
J. Wolthaus1 , H. Uiterwaal2 , K. Kui1 , H. Wijrdeman1 , H. Welleweerd1
1
U.M.C. U TRECHT, Radiation Oncology, Utrecht, Netherlands
2
U.M.C. U TRECHT, Department of Cardiology, Utrecht, Netherlands
Purpose: With an aging population, the number of radiotherapy (RT) patientswith a pacemaker (PM) or implantable cardioverter defibrillators (ICD) is increasing. Previously, planning decisions, precautions during treatment anddevice checks were not regulated. The limited literature available reports alarge variation in radiosensitivity between PMs and ICDs, between devices ofdifferent vendors, types and even within the same type. Safety assurance istherefore necessary for this patient group.We developed a new protocol for
RT patients with a PM or ICD, based on the literature available and our own
experience. The protocol aimed to avoid device failures due to irradiation
during RT.
Materials: Participants from several disciplines were involved, including radiation oncologists (RO), appointment staff, treatment planners, RTTs, cardiotechnicians and medical physicists. The workflow was ordered chronologically and sorted by discipline, to optimise workload efficiency as the numberof patients intended for RT increases. The RO records the vendor name andtype of the device and then delineates the device on the CT scan, if it is in theCT field of view. During planning, the device is kept outside the beam by amargin of 3 cm. A distinction is made between PMs and ICDs, since the latterare more radiosensitive. The maximum cumulative dose, Dc(max), allowedis 5.0 and 2.5 Gy for the PM and ICD, respectively. These thresholds werebased on recommendations in literature which described failures in limitedsize experiments. The Dc is estimated either by computing the dose within
the delineation, or by visual inspection of the device position with respect toDc(max) isodose lines. If Dc > Dc(max), dose reduction can be achievedby changing beam angles, the treatment scheme, or by repositioning the device.If the estimated Dc < 0.5 Gy, the cardio-technician checks the device
twice; before the first and after the last treatment. If Dc > 0.5 Gy, extra checks
are performed weekly and for a follow-up period after RT. This threshold optimises the workload for the cardio-technician. For every RT fraction, RTTs
ensure the cardio-technician is present if a check is planned, and that theresuscitation and audio-visual patient inspection equipment are in order. The
RTTs also place an ICD-magnet on the patient at every fraction to suppress
a possible ICD failure, after careful instruction by a cardio-technician.
Results:
Conclusions: A safety protocol was implemented to prevent cardiac devices
failure for RT patients with a PM or ICD. The workflow was divided among
the relevant disciplines and is therefore seamlessly integrated into the standard workflow. Radiation-related failures are reduced by the cumulative dose
restriction and detected in time by the device check-scheme. Furthermore,registration of this patient group via a protocol allows for more accurate followup and analysis of device failures due to RT

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S YMPOSIUM

Thursday, May 12, 2011
Symposium
30 years of radiation oncology in Gynecologicalcancer - What is the evidence that ‘we’ have created? – Update on randomized trials and Metaanalyses
543 speaker
CHEMORADIATION FOR CERVIX CANCER: HOW FAR HAVE WE
COME?
G. Thomas1
1
O DETTE C ANCER C ENTRE , S UNNYBROOK H EALTH S CIENCES C ENTRE,
Radiation Oncology, North York, Toronto, Canada
Sixty years ago using kilovoltage external beam irradiation and radium
brachytherapy, cure rates in cervical cancer were reported as 80% for stageI, 54% for stage II and 32% for stage III. Increasingly sophisticated radiation techniques using linear accelerators and refined brachytherapy have improved the therapeutic ratio.
After 1999 when the NCI US issued a clinical announcement endorsing
the use of concurrent cisplatin based chemotherapy with pelvic irradiation(CT/RT), this strategy became a "standard of care" and was widely implemented in the developed world. This treatment is not often accessible for the
majority in the developing world where advanced disease is rampant. Wideacceptance of CT/RT for advanced cervical cancer and as post surgical adjuvant for node, margin or parametrial positive early disease was subsequently
supported by an individual patient data based meta analysis of the results of
28 randomized clinical trials involving over 5800 patients. These data demonstrated an absolute survival benefit at five years of 8% (from 60 to 68%) witha significant reduction in both local and distant failure. The magnitude of survival benefit declined with increasing FIGO stage; it was 10% for stage IB/IIA,
7% for stage IIB and 3% for stage IIIB to IVA. The meta analysis confirmedthat the benefit of non-platinum containing concurrent chemotherapy, usually
5FU or 5FU and mitomycin was similar to that of cisplatin. Hypothesis generating data suggested that additional courses of adjuvant chemotherapy may
improve outcomes further. While Image Guided Brachytherapy and External
Beam Therapy have refined radiation delivery further to decrease complication rates no major gains in outcomes were reported between 1999 and 2009.
Duenas-Gonzalez et al (ASCO 2009) reported results for a phase III randomized controlled trial conducted in eight developing countries comparing standard concurrent cisplatin radiation to concurrent cisplatin and gemcitabine
and radiation with two further courses of systemic adjuvant cisplatin and gemcitabine. The experimental regimen, while acutely more toxic, appeared to
improve the progression-free survival at three years by 7%. Reliable longer
term overall survival data are inconclusive as follow up was truncated.
Making future gains is a challenge. Randomized clinical trials become moredifficult as the patient population in the developed countries with trial resources declines because of effective screening and HPV vaccination forsome populations. The next planned international (OUTBACK) trial will include developed and developing countries and will examine the additionof adjuvant courses of carboplatin and taxol to standard concurrent cisplatin/radiation. Similar studies of adjuvant chemotherapy are being conducted in the post surgical adjuvant setting for those at high-risk for recurrence. No molecular targeting agents are ready for inclusion in large randomized trials of CT/RT.
Making a global impact on death rates from advanced cervical cancer remains the greatest challenge.
544 speaker
CERVIXCANCER:
BRACHYTHERAPY
DOSE/RATE/FRACTIONATION
1
C. Haie-Meder
1
I NSTITUT G USTAVE R OUSSY, Radiation Oncology, Villejuif, France
Traditionally, except in some particular centers, brachytherapy (BT) in cervix
cancer has been based on standard dose prescription to point A dose, using
2D X-ray dose planning. Dose-effect relationship to point A has been clearly
defined in the past. A point A dose of at least 80Gy-85Gy (including external
irradiation and BT) was necessary to cure an advanced cervical cancer, stillwith a risk of 35% local failure. Increasing the dose leads to a better local control, but with an increase in morbidity. Recently, the GEC-ESTRO has introduced recommendations based on imaging with applicator in situ using target
volume definition. These new definitions allow an improvement in dose prescription, especially with the use of optimization. Point A nowadays appears
to be a poor surrogate when compared to the dose to an image-guided delineated 3-D target, which even becomes a 4-D target if the tumour regression is
integrated, representing the concept of image-guided adaptive BT (IGABT).
IGABT was also the basis for the development of new applicators, combining

T HURSDAY, M AY 12, 2011
endocavitary and interstitial implants. This type of applications is particularly
indicated when parametrial infiltration is still present after external irradiation.
Recent published data have showed promising results with improvement inlocal control linked to an increase in total dose, reaching 90Gy+, translating
into survival benefit.
Intracavitary BT in the form of low-dose rate (LDR) has been in use for thetreatment of cervical cancer for nearly a century, although the method has
significantly evolved. The introduction of high-dose rate (HDR) machines
progressively modified BT modalities. Comparison between LDR and HDR
brought a lot of controversies. A recent meta-analysis was performed in locally advanced cervix cancer, based on 4 randomized trials with data collected on 1265 patients. The review showed no difference between HDR
and LDR, in terms of local control, survivals and complications. Nowadays,
whatever the dose-rate, the current use of the linear quadratic model allows
treatment modalities comparison, providing the basis for a common language.
With the application of the linear quadratic model, large variations in doses
have been observed, for the same given clinical situation, according to treatment policy and BT modalities. The differences are related to dose-rate, butalso to fraction size, and fraction numbers. It is very important in the future tocorrelate these parameters to the local control, in order to give recommendations on the total EQD2 dose for a given clinical situation, taking into accountthe tumour extension at time of diagnosis and at time of brachytherapy.
Organs at risk (OAR), mainly bladder, vagina, rectum, and sigmoid for BT,
also represent an area where improvements were achieved, however withsome limitations. A clear relationship was evidenced between ICRU rectal
dose and the risk of complications, based on 2D experience. IGABT allows
visible OAR delineation, in particular the sigmoid, which was not studied withthe 2D approach. The D2cc appeared to be relevant to prospectively assess
the risk of complications. Further investigations have to be performed for
bladder as, so far, no correlation has been found between dose and complications. The risk of vaginal complications has not been clinically extensively
studied in the 2D experience. Dose volume constraints for OARs need further
validation, also taking into account the topography.
The ongoing prospective multicenter EMBRACE is a very promising study
which will give relevant information on the clinical and biological interest of
IGABT.
545 speaker
POST-OPERATIVE ADJUVANT THERAPY FOR ENDOMETRIALCANCER. RECENT TRIALS AND THE WAY FORWARD
P. R. Blake1
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department ofRadiotherapy and IBFM-CNR, London, United Kingdom
Post-operative radiotherapy, either external beam (ERT) or brachytherapy(BT), has been used for decades in endometrial cancer patients in an attempt to reduce local and distant relapse rates. In the early 1990s a surveyof cancer centres in the UK showed little consistency between centres withregard to the definition of low, intermediate or high risk groups and the treatment of these patients. Prognosic groups were generally based on histological tumour type and grade and depth of myometrial invasion (often measured
in thirds rather than halves). However, it is notable that the diagnoses ofclear-cell, uterine serous papillary carcinoma (USPC) and carcinosarcoma,
then called malignant mixed mullerian (or mesodermal) tumour, were seldom
made. Equally, lymphovascular space invasion was not usually noted to bepresent or absent. These histological features would now be considered to bepart of the basic dataset required to describe any endometrial tumour. Thesechanges in histological description and staging mean that historical series
are of limited value and inter-trial comparisons across the dates of change in
FIGO staging (notably 1989 and 2008) are difficult.
In the 1990s and early 2000s, when the FIGO 1989 staging system wasused, a number of randomised trials took place to try to determine the valueof post-operative ERT, BT and chemotherapy in post-operative patients withno macroscopic residual disease. Important amongst these in determining
the role of radiotherapy in low and intermediate risk patients are GOG99,
PORTEC 1 and the ASTEC trial radiotherapy arm. PORTEC 2 compared
ERT with BT. In addition, data from the amalgamated NSGO/EORTC trialsof chemotherapy plus radiotherapy versus radiotherapy alone gives some insight into the potential usefulness of chemotherapy in high-risk patients.
The GOG99, PORTEC 1 and ASTEC trials all had slightly different entry
criteria. All the patients in GOG99 had undergone pelvic lymphadenectomy, whereas none in PORTEC had. In the ASTEC trial, patients were recruited from the surgical arm of ASTEC where they had been randomised
to lymphadenectomy or not. Also patients could be entered into the radiotherapy arm after local standard surgery which may or may not have involved lymphadenectomy. However, patients were stratified on the basisof lymphadenectomy prior to randomisation. Of note, the surgical arm of
the ASTEC trial subsequently failed to show any survival benefit from pelvic
lymphadenectomy. ASTEC also included the intermediate risk patients with
FIGO 1989 stage 1c G3 tumours (including clear-cell and USPC) whereas
these patients were excluded from GOG99 and PORTEC 1.
All three trials failed to show an overall survival benefit when comparing radiotherapy with no radiotherapy. A meta-analysis of the 2011 patients in thethree trials was carried out as part of the ASTEC trial report and showed no

T HURSDAY, M AY 12, 2011
benefit (a 0.2% difference in overall survival at five years). Toxicity was worsein the radiotherapy arms. All three trials showed a lower local relapse rate in
the radiotherapy arm.
The PORTEC 2 trial of BT versus ERT in low-intermediate risk patients
showed similar local control rates with lower toxicity in the BT arm.
The NSGO/EORTC trial of radiotherapy versus radiotherapy plus chemotherapy had a number of problems. These related to the very long period of
accrual to both studies and the changes in patient management over that
period. In addition the two trials had not been designed initially to be combined. However, despite these problems, the trial showed a significant benefit
in progression-free survival at 5 years in patients with endometrioid carcinomas. The effect was less evident in patients with clear-cell or USPC.
These trials have indicated that there is probably no benefit in overall survivalin the use of ERT in low-intermediate risk patients. However, intermediatehigh risk patients may benefit from chemotherapy and brachytherapy appears
to be an effective, low-toxicity way of reducing vaginal vault recurrence rates.
The PORTEC 3 study, which is currently underway, is comparing radiotherapy
with or without chemotherapy in a more controlled way than was possible in
the NSGO/EORTC study. If that shows a genuine benefit to the addition ofchemotherapy then the next trial could conceivably be of chemotherapy withor without radiotherapy, either ERT or, more probably, brachytherapy.

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Symposium
Testis
546 speaker
HOW WE LEARNT TO CURE TESTICULAR CANCER
M. Williams1
1
A DDENBROOKE ’ S H OSPITAL, Radiation Oncology, Cambridge, United
Kingdom
Forty years ago the diagnosis of metastatic non-seminoma germ cell tumour
was usually a death sentence. However, some patients with metastatic disease could be cured by radical radiotherapy, including some of those withlimited lung metastases. Complete remission and long-term survival after
treatment with single agent chemotherapy was reported but cure was rare.
A dramatic 35% complete response to treatment with vinblastine andbleomycin was described by Samuels in 1976. The major breakthrough was
the addition of cisplatin to the regimen by Einhorn to develop the PVB regimen (1977). This doubled the complete response rate to 70% and cured ahigh proportion of patients. However, treatment was complicated by paralytic
ileus, abdominal pain, uncontrolled nausea and vomiting and a 10% death
rate from sepsis. Etoposide as a first-line treatment (BEP) was first reported
by Peckham in 1983. Einhorn conducted the landmark trial published in 1987
which established BEP as the optimum treatment (with less toxicity than PVB
and improved results in high risk patients). Treatment related mortality was
4%, with 2% dying of sepsis and 2% of bleomycin pulmonary toxicity.
Treatment has become more tolerable with the development of 5-HT3 antagonist antiemetics. Mortality from neutropaenic sepsis has been reducedby early treatment with improved antibiotics. The death rate from bleomycin
pulmonary toxicity has fallen with the withdrawal of the drug at the first signof toxicity. There is no established predictive test and patients treated solely
with EP have been shown to have an equivalent rate of pulmonary toxicity tothose receiving BEP.
In 1997, the IGCCCG consensus statement on risk categories was published. Good risk patients comprised 56% of the patient population andhad a 92% progression-free 5-year survival when treated with cisplatin based
chemotherapy. They were identified as those having no adverse factors including gross marker elevation, non-pulmonary visceral metastases and mediastinal primary. Intermediate prognosis patients, having only adverse markers, comprised 28% of the population and had an 80% progression-free 5year survival. The remaining high risk category comprised 16% of the patient
population and had a 48% progression-free 5-year survival. This sub-division
allowed patient risk categories to be taken into account when testing potential
improvements to therapy. For good risk patients, carboplatin as a replacement for cisplatin was assessed in 3 randomised trials but found consistently
to result in a 10% reduction in progression-free survival. A subsequent large
trial examined 3 or 4 cycles of BEP delivered over 3 or 5 days. This established 3 cycles of 3-day BEP as the standard of care for patients with goodrisk metastatic non-seminoma.
For intermediate and high risk patients, more intensive chemotherapy wastested. Double-dose Cisplatin and other approaches including VIP and BOPVIP were not shown to be better and had more haematological toxicity.
CBOP-BEP and accelerated BEP are dose dense regimens which remain
under evaluation and a single trial of high dose therapy as initial treatment
has shown no benefit compared to BEP.
The development of effective chemotherapy meant that surveillance without
treatment could be considered for patients with stage I disease. Before thisapproach was introduced by Peckham in 1982, patients were routinely treatedeither with retroperitoneal node dissection in North America or with radiotherapy in Europe. Surveillance was a dramatic innovation and is now established as a standard treatment option. It has been found that the presenceof lymphovascular invasion in the orchidectomy specimen increases the riskof relapse to 50% compared with the risk of 20% for those without this feature. This allows discussion with patients about the risks and benefits ofthe possible use of adjuvant chemotherapy for those without demonstrable
metastases.
There is now considerable evidence that the risk of cardiovascular disease
and second cancer is increased by BEP chemotherapy. One of the largest
papers showed an increase in the relative risk of cardiovascular events estimated between 1.2 and 5.8. It is difficult to translate this into absolute excess risk (AER) but it is about 1.5% per decade; for second cancers the
AER is about 2% per decade. The increase in risk of cardiovascular disease
and second cancer is equivalent to that of the patient being a smoker. Thisis a significant long-term hazard about which patients should be counselled
before treatment, particularly adjuvant treatment. Those treated in the pastshould be informed of this risk to allow it to influence decisions about medical
management of their cardiovascular risk.
Thirty years after it was described, BEP remains the standard treatment formetastatic germ cell cancer. For those who cannot avoid it, nothing is better
than BEP.

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547 speaker

T HURSDAY, M AY 12, 2011
548 speaker

THE PROBLEMS CAUSED BY CURING TESTICULAR CANCER ANDSURVIVORSHIP
S. D. Fosså1
1
O SLO U NIVERSITY H OSPITAL, Resource Center for Late Effects afterCancer Treatment, , Oslo, Norway

LEARNING LESSONS FROM THE PAST: THE PATH FORWARD AND
NEW OPPORTUNITIES
R. Huddart1
1
I NSTITUTE OF C ANCER R ESEARCH & R OYAL M ARSDEN NHS T RUST,
Oncology, Sutton, United Kingdom

Due to improved multimodal management and the introduction of cisplatinbased chemotherapy the 5-year relative survival of testicular cancer has increased from approximately 70% before the "cisplatin area" to >95% thereafter (1). The therapeutic gain has been most evident for metastatic cases.
The long life expectancy of the young testicular cancer survivors (TCSs) together with raising incidence of TC has lead to increased prevalence of TCSs
who are at risk of long-term and late adverse effects (AEs) which threaten
their lives and quality of life. The most frequent life threatening AEs comprisesecond cancer (OR: 1.62 [95% CI: 1.51-1.74]) (2) and -after chemotherapycardiovascular diseases (CVD; OR: 1.44 [95% CI: 1.06-1.91]) (3). With the
exception of leukemia these late events are typically diagnosed after a latencyof >10 years. At that time the survivor no longer is followed-up by cancer
specialists. The relation between radiotherapy and second cancer has beenrecognized for a long time. The etiological role of cisplatin-based chemotherapy for the development of solid second cancer is more unknown. The current
hypothesis of development of endothelial damage, premature atherosclerosis
and of the metabolic syndrome seems to be a relevant start point to explain
the increased risk of CVD in TCSs. As cisplatin is detectable in TCSs’ serum>15 years after their chemotherapy (4), future multi-disciplinary research has
to uncover any pathophysiological relation between AEs and the residual cisplatin serum levels.
20-30% of TC survivors suffer from neuropathy, ototoxicity, hypogonadism
and sub-infertility (5). Though probably of limited influence on survival, thesemorbidities lead to impaired psycho-social well-being, not only of the patients
but also of his family. Long-term participation in the working force may become another issue of clinical research in TCSs. No truly long-term studies
exist which have dealt with this topic in TCSs who 20-30 years after treatment
still should be ahead of the age-related retirement.
The recognition of these late and long-term AEs in TCSs has lead to the establishment of risk-adapted treatment strategies of TC, which challenges thehealth care service as to appropriate follow-up immediately after such "minimized" therapies (frequency of follow-up visits, use of CT versus MR). Afterdiscontinuation of TCSs‘ follow-up within the oncological service another challenge is the organization of aftercare of TCSs at risk aiming for prevention,
early detection and treatment of late AEs. Who should have regular followup? By which health care professionals? How often? What kind of tests
are necessary and which organization is the most cost-effective one? In any
case, appropriate life-long aftercare requires improved under- and post- graduate education of future health care workers, emphasizing the specific longterm health problems of TCSs .Further, future research has to prove that the
reduction of treatment burden has resulted in improved survivorship issues in
TCSs. Finally, both epidemiological, clinical and genetic factors have to be
identified which categorize patients according to their risk of late toxicity.
Treatment of TC has been highly successful, but has also has also emphasized health care professionals‘ need to be aware about long-term and late
toxicity, not only in TCSs ,but in r long-term cancer survivors, in general.
References:

At the end of the 20th century with the advent of new chemotherapy drugs,
radiation and surgical techniques we learnt how to cure most men with testicular cancer. During the early part of the 21st century we have been learning
about the long term consequences of these treatments. Though there areareas such as in poor prognosis and relapsed disease where there is scope
to improve results, it is the challenge of the second decade of this century
to use the information on late effects to aid us in maintaining the high rate ofcures whilst minimising the long term effects of these treatments.
There are several facits to this.
Firstly, we need to carefully re-evaluate our treatment strategies and for eachindividual assess which approach has the minimum burden of treatment andlong term risk. This is not straightforward. The best data on long term effects is based on older treatments that often over time have been modified
e.g. most data on radiotherapy is based on patients receiving ’dogleg ’ pelvic
and para-aortic radiotherapy whilst more modern patients would receive radiotherapy to the para-aortic nodes only; the most mature chemotherapy datais on 4 cycles of PVB whereas 2 or 3 cycles of BEP is more commonly used
now and there is little or no data on single agent carboplatin. A key issue is
we have little or no data on whether less chemotherapy has fewer long term
effects. A key question particularly in stage 1 disease, is whether it is betterto expose most individuals to a low dose treatment (e.g a single cycle of carboplatin) or a few patients to more extensive treatment in terms of global longterm risk of recurrence.
Secondly, we have to continue research into minimising treatment toxicity. Recent years have seen changes in management in response to this data. Examples include using 3 rather than 4 cycles of BEP chemotherapy for good
prognosis NSGCT and The move away from radiotherapy in many centres
to either surveillance or carboplatin for stage 1 seminoma. Other examples
being tested currently are studies investigating whether 1 cycle of BEP is sufficient treatment for stage I NSGCT and trials looking at the intensity of follow
up [MRC TE08 and TRISST] and use of MRI rather than CT [TRISST].
Thirdly, we need to re evaluate how we follow and counsel patients. With
what we know about late effects. follow up may need to be as much as about
detection and management of long term effects as about tumour recurrence.
A key issue is the risk of cardiovascular disease the risk of which has been
estimated to be similar that of a life long smoker. Should we be focussing as
much on counselling the patient of healthy lifestyle and modyfing other cardiac risk factors as looking for recurrence? Who is the best person to do this?
How should this be done? There may be need to learn from multidisciplinary
clinics developed in paediatric oncology.
Finally we need to look at how best to identify patients at risk for toxicity andlook at strategies to minimise this risk. For instance inflammatory and othermarkers are known to be elevated in patients with atherosclerotic cardiovascular disease and coronary calcification can be seen in those at risk. Could
these markers be used to identify patients treated for testicular cancer who
could then be offered secondary prevention? Are there genetic markers thatsuggest an individual is more prone to develop toxicity?
We have made little progress in introducing newer targeted therapies into
testis cancer. Developing these treatments may hold the key to improving
treatment for poor prognosis disease where little has been proven to be better
than BEP but alos may hold hope for less toxic treatment for better prognosis
disease. An issue here is the relative poor funding on basic research into
testis cancer to help us develop mechanism based therapies.
In conclusion, Testicular cancer has been an oncological success story. Ourpatients now have the expectation in most cases of been cured. Our challenge moving forward is to ensure our cured patients survive and prosper inthe long term

1. Verdecchia A, Francisci S, Brenner H, Gatta G, Micheli A, Mangone L,
et al. Recent cancer survival in Europe: a 2000-02 period analysis of
EUROCARE-4 data. Lancet Oncol 2007;8(9):784-96.
2. Travis LB, Fossa SD, Schonfeld SJ, McMaster ML, Lynch CF, Storm H,
et al. Second cancers among 40576 testicular cancer patients: Focus
on long-term survivors. J Natl Cancer Inst 2005;97(18):1354-65.
3. Foss, Gilbert E, Dores GM, Chen J, McGlynn KA, Schonfeld S, et al.
Noncancer causes of death in survivors of testicular cancer. J NatlCancer Inst 2007;99(7):533-44.
4. Travis LB, Beard C, Allan JM, Dahl AA, Feldman DR, Oldenburg J, etal. Testicular Cancer Survivorship: Research Strategies and Recommendations. J Natl Cancer Inst 2010;102;1114-30.
5. Gietema JA, Meinardi MT, Messerschmidt J, Gelevert T, Alt F, Uges
DR, et al. Circulating plasma platinum more than 10 years after cisplatin treatment for testicular cancer. Lancet 2000;355(9209):1075-6.

T HURSDAY, M AY 12, 2011

Teaching lecture
549 speaker
THE CURRENT STATUS OF STEREOTACTIC BODY RADIOTHERAPY
M. Guckenberger1

T EACHING LECTURE

S 225

calculation process as possible. Portal dosimetry is a promising development.
Acknowledgement: The contribution of the other IAEA CRP participants is
acknowledged.

1

U NIVERSITY H OSPITAL W UERZBURG, Department of Radiation Oncology,
Wuerzburg, Germany
Stereotactic body radiotherapy (SBRT) is one of the most successful developments of modern radiotherapy. Practice of SBRT for early stage non-small
cell lung cancer resulted in local tumor control rates of 90% and these excellent results have been achieved consistently in multiple prospective andretrospective studies. Additionally, SBRT is now successfully practiced fora number of different tumor sites like primary and secondary liver cancer or
prostate cancer. Despite these promising clinical outcome data, SBRT is nota well standardized radiotherapy technique but rather an umbrella term forthe practice of dose escalated, high precision radiotherapy in the body part:
this missing standardization makes clinical implementation outside of academicals centres difficult and may also affect implementation of SBRT into
multi-disciplinary guidelines.
This lecture will summarize the latest clinical results of SBRT for early stage
NSCLC. Furthermore, modern imaging, planning and delivery technologies
for SBRT will be discussed. Imaging for treatment planning will focus on integration of FDG-PET for staging and target definition. The current statusof respiration correlated CT imaging for evaluation of breathing induced target motion will be discussed with focus on integration of this 4D information
into the process of treatment planning and image-guidance. Different motion
compensation strategies will be evaluated and their influence on reduced ofsafety margins will be analyzed. Technologies for compensation of inter- andintra-fractional uncertainties will be described.
550 speaker

DEVELOPMENT OF PROCEDURES FOR IN VIVO DOSIMETRY IN
RADIOTHERAPY
P. Mayles1
1

C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics Department, Bebington, Merseyside, United Kingdom

Introduction: In vivo dosimetry is widely recommended as providing the ultimate check of the accuracy of radiotherapy. It can detect major errors, identify
problems with understanding, identify planning system problems (if exit doses
are measured) and is an independent check providing defence in depth. However, the system procedures need to be carefully designed and the costs ofimplementation considered.
Detectors: The first step in establishing an in vivo dosimetry programme isto decide the detectors to be used. These include TLD (Thermoluminescent
Dosimeters), OSL (optically stimulated luminescence) and semiconductor detectors (diodes and MOSFETs). Each system has the common requirementof applying appropriate build-up to the detector to minimise the influence ofsuch factors as source skin distance and field size. An IAEA co-ordinated research project (CRP) entitled "Development of procedures for in vivo dosimetry in radiotherapy", concluded that diodes offer the greatest precision.
Measurement Procedure: A key issue is to establish a method of determining the expected dose. The method recommended by the IAEA CRP wasto use the dose calculated by the treatment planning system at the depth ofdose maximum for each beam. Detectors should be calibrated to indicate thedose at the depth of dose maximum with a specific correction applied for thedifference in SSD between this point and the position of the detector. Having measured the effect of the various influence quantities it is necessary to
carry out a series of verification phantom measurements, ideally using an anthropomorphic phantom. The time taken to carry out in vivo measurements
is a significant consideration. The additional cost per patient is of the orderof e70. A significant part of this cost is the investigation of out-of-tolerance
patient measurements. If too tight a tolerance is chosen this cost will greatly
increase and, if investigation regularly fails to identify a problem with the treatment, the system will rapidly fall into disrepute. It is wise to start with a wide
tolerance which should aim at an out-of-tolerance rate between 5% and 10%.
(In the IAEA CRP a tolerance level of 7% for breast and 5% for other sites
was found to be appropriate.) A procedure for follow up of out-of-tolerance
measurements is required. Appropriate records must be kept of the results
so that analysis of trends can take place. Once the system is established it islikely that variability will reduce allowing a reduction in the tolerance level.
Future developments: Portal imaging devices offer many advantages for invivo dosimetry and at least one commercial system is now available. Advantages of portal dosimetry include reduced impact on patient throughput,
applicability to intensity modulated radiotherapy and derivation of a full 3D
dose distribution. Disadvantages are the increased processing time required
and the impossibility of making measurements with some non-coplanar beamarrangements.
Conclusions: In vivo dosimetry is a useful addition to QA but should not replace careful phantom measurements prior to the introduction of a new technique. Care is required to ensure that the system is as independent of the

Focus on target volume delineation of the upper
GI track
551 speaker
PET IN TARGET VOLUME DELINEATION AND DOSE PLANNING
FOR OESOPHAGEAL CANCER
C. Muijs1
1

U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN -GEN , Department of Radiation Oncology, Groningen, Netherlands

Adequate tumour delineation of esophageal carcinoma for radiotherapy isoften hampered by the poor discriminative value of currently used imaging
modalities, in particular computed tomography (CT), and the inability to relateendoscopic (ultrasound) information to CT-images.
Addition of positron emission tomography (PET) information may improve theaccuracy in the delineation process by adding the functional information of
FDG-PET to the anatomical information of CT.
FDG-PET is able to detect most esophageal tumours. Furthermore, FDGPET/CT seems useful for the detection of locoregional lymph nodes. Overall, integrated FDG-PET/CT has a higher sensitivity, specificity and accuracy
compared to CT or FDG-PET alone. The use of FDG-PET/CT in target volume delineation results in both reductions and increases of the GTV, CTV
and PTV. Subsequently, these changes may result in both inadequate dosecoverage of the PTV and, in clinically relevant changes in dose distributions tonormal tissues. Furthermore, addition of FDG-PET may reduce the inter- andintra-observer variability. For further reduction of the inter-observer variability, various automatic or semi-automatic contouring methods are proposed.
However, usable SUV thresholds, in order to distinguish pathologic tissue
from normal tissue, should be determined and validated. Pathologic evidence supporting the validity of the use of FDG-PET/CT in the tumour delineation process is very limited.FDG-PET based tumour lengths correlate
well with tumour lengths as assessed by pathologic examination. However,tumour length correlation does not automatically mean correct tumour imaging in terms of tumour localisation. Finally, the use of FDG-PET for tumour
delineation for radiotherapy should be validated in terms of clinical outcome.
So far there are no studies demonstrating the use of PET/CT in terms of improved locoregional control or survival.
Since evidence is very limited standard implementation of FDG-PET/CT into
the tumour delineation process for radiation treatment seems unjustified andneeds further clinical validation first. This is now subject of a prospective
multicenter study in the Netherlands.
552 speaker
4D-CT AND PET IN TARGET VOLUME DELINEATION AND DOSE
PLANNING FOR PANCREATIC CANCER
G. M. Cattaneo1 , P. Passoni2 , B. Longobardi1 , N. Slim2 , N. di Muzio2 , C.
Riccardo1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Radiotherapy, Milan, Italy
Background and aim. Despite a number of new chemotherapeutic agents
tested in combination with radiotherapy (RT), prognosis of pancreatic ductal adenocarcinoma (PDA) remains disappointing. Delivery of higher dosesof standard fractionated RT or hypofractionation could provide a benefit inlocal control. In both cases, a more selective irradiation of tumour is mandatory to limit the risk of actinic toxicity. The accurate definition of abdominal
diseases is problematic due to organ motion mainly related to the respiratory
process. In contrast enhanced CE-4D-CT procedure a reconstructed 3D data
set is created for each phase and intrafractional organ mobility can thus be
accurately quantified; moreover this protocol yielded images allowing gooddifferentiation between neoplastic tissues, normal tissues and regional vessels. Pancreatic tumours in general are FDG-avid and FDG-PET parameters
have been shown to be of prognostic value for local control. The rational forusing PET in target volume definition is the higher sensitivity and specificityof PET for tumour tissue in comparison with CT and MRI. FDG-PET/CT has
been used to define target volume delineation in a few studies and the actual
value of adding FDG-PET to tumour volume delineation however is under investigation.
Material and methods. Given the availability in our department of 4DCT,PET and IMRT/IGRT (Tomotherapy) technologies, a Phase I study was defined to treat locally advanced PDA using a (moderate) hypofractionated irradiation regime with concomitant chemotherapy. From March 2006, 24 patients (age: 64 ± 10 y, range: 4086 y) affected by stage III PDA and candidate to concomitant chemoradiotherapy underwent a WB PET/CT and CE-

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4D-CT study performed using an integrated PET/CT system within a clinicalradiological protocol approved by the internal ethics committee.
This study investigated the following main points: the impact of the CE-4DCT and PET imaging technique on RT planning; the intra-observer variability
in the contour definition procedure and the possibility of dose escalation in a
sub-tumour volume area with an integrated boost approach.
Results and conclusions. The planning definition of PDA derived from the
4D technology could significantly avoid geographic misses and/or reduce
the treated volume with consequent sparing of healthy tissues. The intraobserver variability in the 4D-CT-based contour definition procedure was considered acceptable. The role of PET needs further investigations.

T HURSDAY, M AY 12, 2011

Symposium
ESTRO-ESGO Joint Symposium: Gynecological
Cancer - What is the evidence-based that is being
created right now?- The best of clinical trials
553 speaker
CERVIX AND ENDOMETRIUM CANCER: IMAGING/CONTOURING
AND TECHNOLOGY (IMRT, IGRT)
M. Powell
Abstract not received.

554 speaker
CERVIX CANCER: IMAGE GUIDED ADAPTIVE BRACHYTHERAPY IN
THE SETTING OF DEFINITIVE RADIO-CHEMOTHERAPY - STATUS
OF CURRENT MULTI-CENTRE STUDIESJ. C. Lindegaard1 , C. Haie-Meder2 , C. Brunaud3 , E. Van Limbergen4 , C.
Kirisits5 , K. Tanderup6 , R. Pötter5
A ARHUS U NIVERSITY H OSPITAL, Department of Radiation Oncology,
Aarhus C, Denmark
2
I NSTITUT G USTAVE R OUSSY, Villejuif, France
3
FNCLCC (F ÉDÉRATION N ATIONALE DES C ENTRES DE L UTTE C ONTRE LE
C ANCER ), SFRO, Paris, France
4
U NIVERSITY H OSPITAL G ASTHUISBERG, Leuven, Belgium
5
M EDICAL U NIVERSITY V IENNA , AKH, Vienna, Austria
6
A ARHUS U NIVERSITY H OSPITAL, Aarhus C, Denmark
1

Brachytherapy (BT) has been an integrated part of definitive radiotherapy
in locally advanced cervical cancer for a century. Based on orthogonal
X-rays (2DBT) local control rates in the range 50-85% and major morbidity in
7-15% of the pts have been reported. Although the addition of concomitantchemotherapy has improved survival, significant therapeutic challenges
remain, especially in locally advanced disease. Since the publication of
the GEC ESTRO recommendations in 2005, the concept of image guided
adaptive brachytherapy (IGABT) has gained significant momentum. IGABT
is based on an adaptive 4D target concept and requires the use of imaging(preferably MRI) with the BT applicator in situ at the time of BT. IGABT isnow considered the gold standard in several countries, but so far only limited
clinical data has been published. However, 3 multi-centre studies (STIC,EMBRACE and retroEMBRACE) are now in the pipeline.
The first prospective multi-centre study including 705 pts was performed
2005-2007 in France based on a national grant: "Soutien aux Techniques
Innovantes et Coteuses" (STIC). The STIC study was not randomized, so
decision to use 2DBT or IGABT (mainly CT) was based on availability. About
2/3 of the pts were subjected to planned surgery, leaving 235 pts treated withdefinitive radio-chemotherapy. The FIGO stage distribution in the definitive
radio-chemotherapy group was IB1 7%, stage IB2-IIB 63% and IIIA-IIIB in
30%. There were no clinical significant difference between 2DBT and IGABTwith regard to TRAK, dose to point-A and the ICRU points The mean D90 for
HR CTV and IR CTV in the 117 pts treated with IGABT were 73 Gy and 62
Gy (EQD2), respectively. With IGABT the mean D2cc for OAR were all below
current recommended constraints. Local control at 2 years was improved
from 74 to 79% and G3-4 morbidity reduced from 23 to 3% when comparing
2DBT and IGABT. No significant effect was seen on disease free survival.
IGABT also improved local control by 8-9% and decreased morbidity by
about 5% in pts also treated with surgery. However, even with IGABT thelevel of late morbidity for the combined radio-chemo-surgical approach (9%)
was higher than for definitive radio-chemotherapy (3%).
In 2008 a prospective observational phase 4 study with the aim of implementing MRI based IGABT in locally advanced cervical cancer (EMBRACE)
in a multicentre and multinational setting was opened (www.embrace.dk).
EMBRACE requires strict use of external beam radiotherapy (EBRT) but isopen to institutional dose prescription of BT as long as the GEC ESTRO
guidelines are employed and MRI with the BT applicator in situ is used for
BT dose planning. In Nov. 2010 the first data extract was analyzed on the
305 patients accrued from 19 centres at that time point. Treatment wascompleted in 253 pts and outcome data was available for 188 pts with a
median follow-up time of 9 months. FIGO stage distribution showed IB1 4%,
IB2 17%, IIA 8%, IIB 45%, IIIA 1%, IIIB 20% and stage IV 5%. EBRT wasgiven with 3D conformal technique in 81% and IMRT in 19%. The mediandose to the elective target was 45 Gy in 25 fractions. Para-aortic EBRT was
included in 17% of the pts. Nodal boost giving and additional 10-20 Gy by
EBRT was given to 33% of the pts. Parametrial boost was hardly used (1%).
Concomitant chemotherapy was given to 92% of pts. The BT technique
was intracavitary only in 71% and combined intracavitary/interstitial in 29%.
For D90 of HR CTV and IR CTV mean values of 89 Gy and 69 Gy (EQD2)
were found. For OAR the mean D2cc values were 76, 64, 62 and 63 Gy(EQD2) for bladder, rectum, sigmoid and bowel, respectively. The 1 year
local control rate and overall survival rate is at the moment 97 and 94%,
respectively. For morbidity (CTCAE) 3 pts have experience G3 morbidity

T HURSDAY, M AY 12, 2011
(oedema, pain, radionecrosis) and 2 pts G4 vaginal stenosis. No G3-4
bladder and gastro-intestinal morbidity has so far been reported. HR QoLquestionnaire (C30+CX24) based on a high response rate (82%) points todiarrhoea, fatigue, insomnia, hot flushes and fear of pain at intercourse as
the dominating quality of life aspects following treatment.
The latest multi-centre initiative involves the retroEMBRACE study
targeting about 600 pts treated at 9 institutions experienced in IGABTin the pre-EMBRACE era.
The web-based retroEMBRACE database(www.retroembrace.com) has been open since Oct. 2010 and 175 pts havebeen registered so far. The result of the first analysis has so far shown aremarkably similarity to the EMBRACE data.
In conclusion, IGABT for definitive radio-chemotherapy in locally advanced
cervical cancer performed according to the GEC ESTRO guidelines is
feasible in a multi-centre and multinational setting. IGABT provides a highdose in the tumour target and significant sparing of nearby OAR. The STIC
trial points to a significant improvement of the therapeutic window, which
may be widened even further based on the preliminary data from EMBRACE
and retroEMBRACE.

555 speaker
CERVIX CANCER: ONGOING TRIALS AND THE GCIG INITATIVE
H. Kitchener
Abstract not received.

556 speaker
ADJUVANT TREATMENT OF ENDOMETRIAL CANCER: CURRENTEVIDENCE AND ONGOING TRIALS.
C. Creutzberg1
1
L EIDEN U NIVERSITY M EDICAL C ENTER, Radiation Oncology, Leiden,
Netherlands

Adjuvant treatment for endometrial carcinoma (EC) is risk-based. The majority of patients are at low risk of recurrence and are cured with surgery alone.
The indication for adjuvant radiotherapy, brachytherapy and /or chemotherapy
is based on the classical adverse prognostic factors stage, age, grade, histological type, depth of myometrial invasion and lymph-vascular space invasion.
Over the last decade, four randomized trials have established the roleof pelvic external beam radiation therapy (EBRT) in intermediate-risk EC,
demonstrating that EBRT provides a highly significant reduction of vaginal
and pelvic recurrence, but without survival advantage and at the cost of increased gastro-intestinal (GI) toxicity. The evidence from these trials has
resulted in reduction of the use of EBRT. Patients with high-intermediate risk
features (advanced age, high tumor grade, deep myometrial invasion andlymph-vascular space invasion as defined in the PORTEC-1 and GOG#99 trials) have approximately 20% risk of locoregional relapse without further treatment. For these HIR patients, the PORTEC-2 trial (2002-2006) has demonstrated that vaginal brachytherapy (VBT) can safely replace EBRT in HIR endometrial carcinoma, to maximize vaginal control with less toxicity. Five-year
vaginal recurrence rates were 1.8% in the VBT group and 1.6% after EBRT,
and disease-free survival (83% vs 78%) and overall survival (85% vs 80%)
were similar in the two groups. Patients treated with VBT reported significantly less GI toxicity and better quality of life than those who had EBRT. The
current standard adjuvant treatment for EC patients with HIR features has
therefore shifted from EBRT to VBT alone.
The challenge for current research is improving survival rates for women withhigh-risk and/or advanced stage disease. Patients with grade 3 EC with deep
myometrial invasion, and those with FIGO 2009 stage II and III disease or withserous or clear cell histology are at increased risk of distant metastases. For
these patients, EBRT continues to be the most effective treatment to ensure
pelvic control. Adjuvant chemotherapy (CT) has been compared to EBRT in
the JGOG and Italian trials, without significant differences in survival or relapse rates. In the GOG#122 trial for stage III and IV EC, 8 cycles of doxorubicin and cisplatin (AP) was compared to whole-abdominal radiation therapy(WART). This trial did not only investigate adjuvant treatment, as stage IV
represents disseminated disease and residual macroscopic disease up to 2
cm was allowed. Predicted adjusted 5-year survival was significantly betterfor AP (55 vs 42%), but toxicity was substantial. Event rates were similar (54vs 50%), and unadjusted predicted 5-year PFS rates were 42 vs 38%. WART
cannot be recommended for treatment of abdominal disease spread.
Combinations of radiotherapy and chemotherapy seem more effective. The
NSGO 9501/EORTC 55991 trial which compared EBRT with EBRT preceded
or followed by 4 cycles of doxorubicin and cisplatin containing chemotherapy(mostly AP), was the first to show a significant 7% increase in progressionfree survival with the addition of chemotherapy (79 vs 72%, p=0.03), however
overall survival was not significantly improved. 27% of patients did not complete chemotherapy. The trial population involved mainly intermediate-riskpatients, with 50% stage I and only 8% stage III disease.
In both NSGO/EORTC and GOG#122 trials the 20% patients with serous cancers did not benefit from chemotherapy, with overlapping PFS and OS curves,

S YMPOSIUM

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in contrast to the benefit found for endometrioid histology. This underlines theneed to establish the efficacy of adjuvant chemotherapy for serous cancers in
randomized trials.
Current ongoing trials for adjuvant treatment of EC are focusing on the roles ofchemotherapy, radiotherapy and combinations. In the international PORTEC3 trial for high-risk stage I-III EC, EBRT alone is compared to EBRT combined with chemotherapy, starting both treatments early (2 cycles of cisplatin
during EBRT, and 4 cycles of carboplatin and paclitaxel after completion of
EBRT). PORTEC-3 investigates both survival benefit and ’cost’ in terms of
toxicity and quality of life for these elderly patients. The GOG#249 trial forhigh-intermediate and high-risk stage I-II EC compares EBRT with VBT plus
3 cycles of carboplatin and paclitaxel. The GOG#258 trial includes stage IIIIV EC patients, comparing the same EBRT and CT combination schedule asused in PORTEC3 with 6 cycles of carboplatin and paclitaxel alone. These
trials will answer many of the unresolved questions regarding optimal treatment of EC patients with high-risk features, and provide a unique opportunity
for translational research.

S 228S YMPOSIUM

T HURSDAY, M AY 12, 2011

Interactive session

Symposium

Ethical issues in managing oncology patients

Incorporation of molecular and genetic patterns indose response models

557 speaker
ETHICAL ISSUES IN MANAGING ONCOLOGY PATIENTS
S. Guglani1 , K. Benstead1 , R. George2 3 , F. R. Macbeth4 , T. Roques5
1

G LOUCESTERSHIRE H OSPITALS NHS F OUNDATION T RUST, ClinicalOncology, Cheltenham, United Kingdom
2
C ICELY S AUNDERS I NSTITUTE KCL, Clinical Ehtics, London, United
Kingdom
3
G UYS AND S T T HOMAS NHS F OUNDATION T RUST, Palliative Care,
London, United Kingdom
4
N ATIONAL I NSTITUTE FOR H EALTH AND C LINICAL E XCELLENCE, ClinicalOncology, London, United Kingdom
5
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, ClinicalOncology, Norwich, United Kingdom
The practice of oncology demands clinical and technical excellence: full assessment of the patient with staging and typing of their tumour, and treatment
with evidence-based interventions delivered with technical skill within a suitably developed operational framework. Our undergraduate and post-graduate
training focuses on developing these competencies to an acceptable level.
Although such expertise is necessary, it is not sufficient for the good practiceof oncology. Difficult judgments about how patients are most appropriately
managed have to be balanced against seemingly unlimited therapeutic possibilities. Such ethical judgments infuse the daily practice of oncology. Although open to rational consideration, ethical debate is arguably lacking in
the practice of oncology, such that individual value judgments can profoundly
affect treatment decisions (Seale, 2010)" The risks and benefits of potentially toxic radical treatment may be perceived
very differently between clinicians and patients or indeed between clinicians.
What are the implications of this for valid ’informed’ consent, telling the truth
to patients and respecting their autonomy?
" In the treatment of advanced disease might such variation in evaluation influence decisions to withhold or continue active treatment.
" When the prognosis is poor, are doctors reluctant to withdraw or withhold
active treatment because of concern that such omissions are culpable andpotentially contributory to their patients’ premature death?
" What is the balance between fostering hope and deceiving patients about
the reality of their condition?
" How do we decide on the timing and thresholds for withdrawing active treatments are we led by our patients and their perceptions of futility, harm andbest interests or should medicine have a definable set of principles for such
judgments?
" How much do our duties as doctors extend beyond the care of individual patients, to a consideration of broader societal healthcare needs and judgments
about resource distribution?
" The National Health Service (NHS) has traditionally promoted a utilitarian view of healthcare that, while championing good care at the individuallevel, has recognised the need for fair and equitable distribution of limited
resources. Institutions such as the National Institute for Health and ClinicalExcellence (NICE) have reflected this drive, in judging new interventions not
only on clinical but also cost-effectiveness criteria. Is this legitimate or mighta free market deliver better care for cancer patients?
" Might such models fragment cancer care for example by separating specialist palliative care from active cancer treatment, rather than seamlessly
incorporating them in parallel (Temel, 2010)? Further, might such models of
healthcare be driven primarily, and potentially inequitably, by technologicalpossibility, demand and expectation rather than the universal application of
the basics of good treatment?
Through a session involving case presentations and live debate between an
audience and panel, we aim to explore these and related issues.
REFERENCES:
Seale, C. (2010) ’The role of doctors’ religious faith and ethnicity in taking
ethically controversial decisions during end-of-life care’, Journal of Medical
Ethics, vol. 36, pp. 677-682
Temel, J. S. et al (2010) ’Early palliative care for patients with metastatic nonsmall cell lung cancer’, New England Journal of Medicine, vol. 363, pp. 733742

558 speaker
MODELLING TUMOUR CONTROL OUTCOME BASED ON BIOLOGICAL IMAGING RESPONSE
M. Alber1
1
U NIVERSITÄTSKLINIK FÜR R ADIOONKOLOGIE, Medical Physics, Tübingen,Germany
Functional imaging modalities, such as some magnetic resonance (MRI)
techniques, positron emission tomography (PET) with specific biomarkers orcontrast dynamics measurements with computed tomography (DC-CT) havebeen applied to characterize the structural and biological diversity of tumours,
and to monitor the response of tumours to radiotherapy.
Naturally, functional imaging is fraught with difficulties, many of which originate directly from the complex nature of tumours themselves. Tumours areoften highly irregular entities both biologically and structurally, whose properties are variable across their volume down to length scales of tens of micrometers. They show a highly heterogeneous and often delayed response totherapy. A multitude of interlinked parameters, such as proliferation rate, cellsensitivity and vascular status influence therapy success. Finally, functional
imaging methods often provide substitute information (e.g. diffusion weighted
MRI), are not overly specific (e.g. 18F-FDG PET) or are difficult to handle andinterpret, with associated issues concerning sensitivity, specificity and quantification.
For these reasons, ab-initio mechanistic models of tumour control using the
input of functional imaging are bound to fail, especially as each single imaging modality only offers an incomplete picture. However, several functional
imaging techniques have proven their predictive power either applied pretreatment or as a continuous monitor of therapy response. In the very least,
an indication of therapy success could be given shortly after the end of treatment; in the very best a coarse stratification of tumours was established.
Ideally, functional imaging provides information about a potential failure oftreatment as early as possible in the treatment course in order to allow fortimely adaptations of the treatment regime. It is here that models can lend anedge to functional imaging.
In many promising applications of functional imaging, the common denominator appears to be the tumour vasculature and -perfusion. Abnormal properties
can be both the sign and the mediator of therapy resistance, whereby in thecontext of radiotherapy, hypoxia may play an important role. An abnormal or
deficient vasculature can be picked up by a variety of imaging methods, andcan be used to stratify patients into risk groups. Of course, the predictionof therapy success from a perfusion map of the tumour is hopeless withoutcomplementary information. However, models can be devised that address
the following questions in a biologically relevant manner: what is the influenceof tumour volume on outcome? How can greatly varying image intensities be
combined to one quantity? How can multiple images of the same tumour be
combined to yield more information?
In the presence of so many unknowns, these models must be largely descriptive. Yet, they can be built around some basic assumptions: linearity
in volume, exponential dose-effect and dominance of the most resistant cell
sub-type. Functional images would then be used to adapt the open parameters of the model spatially and temporally, in case of repeated imaging fortherapy monitoring. An example of this kind of model can be given for repeated hypoxia-sensitive PET imaging, where the crucial parameter is thetime-to-reoxygenation of the most radioresistant cell sub-type.
Apart from geometrical information about tumour location and extent, functional imaging also offers spatial and temporal information about tumour composition. The latter is of great potential use for treatment adaptation and selection. To date, descriptive models of tumour response can be formulated
that support this decision making progress, and the use of multiple imaging
modalities in parallel.
559 speaker
INCLUDING MOLECULAR AND GENETIC PREDICTORS IN NORMAL
TISSUE DOSE-VOLUME MODELLING
T. Rancati1
1
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Prostate
Program, Milan, Italy
Radiation-related side effects are related to a number of patient- andtreatment-related factors.
With the advent of newer technologies, there is increased interest in decreasing the incidence of radiotherapy side effects. For this reasons, in recent
years, increased interest arose in models that could achieve better complication prediction. With the availability of more accurate individual toxicity estimates, a better increased dose can be prescribed and this translates to abetter tumor control.
Some recently published studies have shown that current NTCP models can

T HURSDAY, M AY 12, 2011
be improved by incorporating clinical risk factors into model formulation.
A further important step is the includion of molecular/genetic predictors into
NTCP models. This issue is still at a very primitive stage and should be elucidated because, given the same set of clinical/dosimetric factors, patient-to
patient variability in normal tissue response to radiation has been widely recognized in clinical practice, suggesting that this phenomenon might be, atleast in part, genetically driven.
In this presentation data on molecular/genetic markers influencing radioinduced toxicity are presented, together with the first findings supporting the
hypothesis that a genetically determined doseresponse relationship is possible and could be used to predict the probability of side effects associated withradiotherapy and serve as a rational basis for individualized radiation doseprescriptions.
References:
1. Alsner et al Differential gene expression before and after ionizing radiation of subcutaneous fibroblasts identifies breast cancer patients
resistant to radiation-induced fibrosis. RO 07
2. Cesaretti JA et al A genetically determined dose-volume histogram
predicts for rectal bleeding among patients treated with prostatebrachytherapy. IJROBP 07
3. Valdagni et al To bleed or not to bleed. A prediction based on individual gene profiling combined with dose-volume histogram shapes inprostate cancer patients undergoing three-dimensional conformal radiation therapy. IJROBP 09
4. Z. Liao, Q.Wei, M.K. Martel et al. Incorporating SNPs as biomarkers
to improve fit of the Lyman model for radiation pneumonitis. IJROBP
10560 speaker
THE INCORPORATION OF NORMAL TISSUE FUNCTIONAL IMAGING IN DOSE RESPONSE STUDIES
M. Partridge1
1
T HE I NSTITUTE OF C ANCER R ESEARCH, Joint Department of Physics,
Sutton, United Kingdom

Considerable advances have been made in recent years in the use of imaging for the assessment of normal tissue function. A range of nuclear medicine
techniques exist that have been shown to be useful for assessment of damage to the heart, lungs, kidneys, digestive tract, salivary glands, brain andthe skeleton. Magnetic resonance imaging can also provide information on
tissue damage through measurements of diffusion and perfusion and thoughspecialised techniques such as 3-He hyperpolarized gas imaging in the lungs
and diffusion tensor imaging in the brain.
Functional imaging can be used to provide valuable input to radiotherapy
dose-response modelling in three different ways: i) to measure baseline normal organ function and therefore better assess the risk of or distinguish thedirect effects of radiation-related toxicity; ii) to observe early normal tissue
damage, possible before the onset of clinical symptoms, and intervene to either prevent further damage or better manage consequential toxicities; iii) as
a purely observational tool to investigate correlations between radiation dose
distribution and toxicity.
However, there are considerable practical and technical challenges that must
be overcome before the majority of these functional techniques can beroutinely used for dose-response prediction. Many of the emerging functional techniques, although highly promising, are highly scanner-dependent;
standardised protocols will therefore need to be developed to allow theirwidespread use. Prediction of the dose-response of normal tissues using
imaging information is also a complex problem. Reproducible and accuratequantitative imaging in itself may not be sufficient. It might be important tounderstand the link between the observed signal from an imaging device andmicroscale function (for example microscopic heterogeneity in tracer uptake
or for MRI water mobility). Studies comparing imaging signatures with histology are certainly required in some cases. The micro and mesoscopic mechanisms governing radiation toxicity, such as repair, cell migration and repopulation may also be important, together with the characteristic volume of anorgan which can be repopulated without loss of function (functional sub-unit).
Many of these questions are currently only partially answered.
Despite the abovementioned limitations, useful models have been presented
for assessment of the risk of radiation pneumonitis in lung cancer patients,
with lung function measured using 99m-Tc-labelled macro-aggregated albumin SPECT, hyperpolarized 3-He MRI ventilation or 4DCT. Functional imaging has also been shown to be useful for assessment of radiation-induced
liver disease and radiation damage to the salivary glands using diffusionweighted MRI and a range of nuclear medicine techniques.
For significant progress to be made in this field, good quality clinical data areessential. Prospective clinical studies where functional imaging is acquiredalongside the traditional radiotherapy and clinical outcome data, following
standardised imaging protocols and toxicity reporting schemes, are clearly

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S YMPOSIUM

required. Such data will allow us to more fully exploit the great potential benefits that functional imaging has to offer in the understanding and modellingof radiation toxicity.

New beam acceleration for proton and ion therapy
561 speaker
COMPACT ELECTROMAGETIC ACCELERATIONSDELIVERIES FOR PROTON AND ION THERAPY
M. Schippers1

AND

BEAM

1
PAUL S CHERRER I NSTITUTE (PSI), Department of Medical Physics,
Villingen, Switzerland

The strong increase of interest in radiation therapy with protons or carbon ionsat clinics has encouraged new developments in accelerator technology andan increase of the different possibilities offered by various vendors. Typicallya cyclotron or a synchrotron is used as an accelerator, followed by a beamtransport system that sends the particle beam to one of 3-4 treatment rooms.
In principle this concentration yields a better efficiency and a concentration ofexpertise. However, installation of these multi-room facilities require substantial financial investments. Furthermore, in regions with low population density
the capacity of such large facilities may be not completely exhausted, withnegative financial consequences. For this reason there is a strong interest
to decrease the costs of the accelerator-transport-gantry system. Scale reduction is the typical approach pursued by several groups, with a single-room
particle treatment facility as the ultimate goal. For the time being carbon ion
therapy in a single-room facility is out of the question, but methods to reduce
the size of the accelerator and of the gantry are being investigated.For protons studies are in progress to combine functions of transport and gantry.
Several approaches are in development to reduce the size of the accelerator
or to combine functions of accelerator and energy selection. However, in all
small systems compromises are made. In order to judge new developments,
one has not only to consider their (usually claimed economic) advantages, but
above all whether they can at least provide treatments with the same quality
as the current particle therapy modalities. In this talk different techniques,
accelerators and proposals will be reviewed.
562 speaker
THE DIELECTRIC WALL ACCELERATOR: INDEPENDENT EVALUATION OF PROJECT STATUS [1]J. R. Alonso1
1
L AWRENCE B ERKELEY N ATIONAL L ABORATORY, Accelerator and Fusion
Research Division, Berkeley, Califorina, USA
High priority is being placed on development of new sources of protons for radiotherapy that are compact, and offer price-performance benefits over existing technology. The Dielectric Wall Accelerator (DWA) concept is capable ofachieving these goals, but substantial engineering and technical challenges
still lie ahead. Based on new materials capable of supporting extremely highvoltages for very short periods of time, the DWA is believed to be capable ofachieving accelerating gradients of 100 MV/meter, making a 200 MeV proton
linear accelerator about 2 meters long. By comparison, a "conventional" (RF)200 MeV proton linac might be over 100 meters long. The original concept
showed a DWA structure mounted on a gantry rotating around a patient, much
like current electron linacs used for x-ray therapy. The Lawrence Livermore
National Laboratory team, led by George Caporaso, is a world-leading developer of induction linacs, machines used typically for flash radiography withextremely high currents (kiloamperes) of electrons in very short (nanosecond)
pulses. They proposed using the induction-linac concept, with the new "HGI"(High Gradient Insulator) materials and other innovations to provide proton
pulses at intensity and repetition rates suitable for radiotherapy applications.
In 2007, TomoTherapy Inc. teamed up with the LLNL group through the US
Government’s CRADA process to develop the DWA as a proton-therapy device. In 2008, CPAC (Compact Particle Accelerator Corporation) was spunoff from TomoTherapy, and has taken responsibility for commercialization of
the DWA.
Many technical challenges presented themselves, both in the accelerator systems and in adapting the pulsed beam to clinical beam delivery. Some havebeen overcome, others are at various stages of development. Currently, somecomponents of the accelerating system are reaching planned performancelevels, and preliminary acceleration tests have shown energy gain in particles (electrons and protons). Effective gradients for short test assemblies
including all necessary components (switches, charging strips (Blumlines),
HGI toroids) are still substantially below the 100 MV/m level.
However, a realistic roadmap has been developed by CPAC that calls for several milestones leading up to completion in Q4 of 2012 of a 150 MeV prototype with beam performance suitable for therapy delivery. The machine
configuration, with a conservative accelerating gradient, and an industriallyproven proton injector, will be too long to provide isocentric beams without theaddition of a downstream gantry, but a robotic patient positioner will provideS 230S YMPOSIUM

some flexibility for treatment with the available static horizontal beam.
Development will continue, and in principle there do not seem to be any technical show-stoppers to in time achieving the high gradients and compact
injector designs necessary to gantry-mount the machine, but at present there
is no published timetable for these developments.
[1] The ESTRO Organizers requested the author, who has no connection
with the DWA project, to perform an independent assessment of its progress
towards readiness as an effective source of beams for proton therapy.

T HURSDAY, M AY 12, 2011
majority of experiments.
Conclusion: The successful systematic in vitro cell experiments at laser
driven particle beams form an important milestone on the way to the development of clinically applicable laser particle accelerators. Currently, the laser
driven proton beam will be improved with respect to maximum energy as wellas to spectral and spatial shaping in order to enable radiobiological animal
experiments in a subsequent step.
This work has been supported by the German Federal Ministry of Education
and Research (BMBF), grant no. 03ZIK445.

563 speaker
LASER DRIVEN ACCELERATORS FOR RADIOBIOLOGY EXPERIMENT
J. Pawelke1 2 , M. Baumann1 , E. Beyreuther2 , T. Burris-Mog2 , T. Cowan2 ,Y. Dammene1 , W. Enghardt1 2 , M. Kaluza3 , L. Karsch1 , S. Kraft2 , L.
Laschinsky1 , E. Leßmann2 , J. Metzkes2 , D. Naumburger1 , M. Nicolai3 , C.
Richter1 2 , H. P. Schlenvoigt3 , U. Schramm2 , M. Schürer1 , J. Woithe1 , K.
Zeil2
1
O NCO R AY - N ATIONAL C ENTER FOR R ADIATION R ESEARCH IN O NCOL OGY , Technische Universität Dresden, Dresden, Germany
2
H ELMHOLTZ -Z ENTRUM D RESDEN R OSSENDORF, Institute of Radiation
Physics, Dresden, Germany
3
F RIEDRICH -S CHILLER -U NIVERSITÄT, Institute for Optics and Quantum
Electronics, Jena, Germany
Objective: The novel technology of particle acceleration based on high intensity lasers promises to reduce the large dimensions and high costs of present
hadron (proton and light ion) therapy facilities. However, the therapeutically
relevant parameters of laser driven particle beams dramatically differ fromthose of beams from conventional electromagnetic accelerators: The duty
cycle is extremely low, whereas the number of particles and thus the dose
rate per pulse is very high. Laser accelerated particle beams show a broad
energy spectrum and substantial intensity fluctuations from pulse to pulse.
The consequences of these properties on (i) dosimetry, (ii) radiobiological effectiveness, (iii) solutions for therapy beam deliveries, and (iv) therapy quality
assurance have to be investigated systematically. With this purpose as wellas to develop a compact high power laser system delivering therapeutic particle beams with a range of 30 cm in water at a dose rate exceeding 2 Gy/(minl) as the main technical challenge, the German research project onCOOPtics
was started.
Material and Methods: In a first step of the translational chain for developing
the laser based technology towards applicability in radiation therapy, radiobiological in vitro cell experiments were established. At first, electron pulses
were generated using the Titanium:Sapphire 10 terawatt laser system JeTi
at Friedrich-Schiller-University Jena. Laser pulses (80 fs duration, 0.8 J energy, 2.5 Hz repetition rate) were focused into a helium gas jet, accelerating
electrons to energies of up to a few ten MeV. In order to perform proton experiments, the increased laser intensity of the 150 terawatt laser system Draco,
recently installed at the Helmholtz-Zentrum Dresden Rossendorf, was necessary. Laser pulses (30 fs duration, 3.5 J energy, 0.1 Hz repetition rate) werefocused to a focal spot of 3 mm diameter on a 2 mm thick Ti foil, accelerating
protons to a maximum energy of up to 20 MeV.
Before starting irradiation experiments, the laser accelerator systems had to
be extensively tuned and optimized with respect to intensity, energy distribution, spot size, stability and reliability of the particle beams. Furthermore,beam filtering and transport to an in-air irradiation site were developed andrealised. At this, compact magnetic dipole beam filters together with special
aperture setups were used to shape the particle distribution appropriate forthe cell irradiation experiments and to efficiently suppress particles with energies below a lower cut-off energy and background radiation at the cell sample
position. The particle beams were controlled and monitored in real-time bymeans of an ionization chamber and an in-house Faraday Cup for defineddose delivery of the prescribed dose. Moreover, EBT radiochromic film wasused for retrospective precise determination of absolute dose delivered to thecell monolayer and for verification of a homogeneous dose distribution at thetarget.
Cell irradiations with doses in the range of 0.3 to 10 Gy have been performed for squamous cell carcinoma and non malignant cell lines. Following irradiation, the dose-dependent cellular survival was measured using theclonogenic survival assay. Additionally, the immunohistochemical detectionof co-localized gH2AX and 53BP1 molecules was applied to analyze DNA
double-strand breaks which remain in the cells 24 hours post-irradiation. Reference irradiation with a continuous beam from conventional accelerator, aclinical electron LINAC and a proton tandem accelerator, respectively, wasperformed in parallel with experiments at the laser accelerated pulses.
Results: All the key requirements for systematic radiobiological cell experiments have been fulfilled, such as the supply of a reasonably stable andreproducible laser-accelerated particle beam providing homogeneous dosedelivery on a desired macroscopic irradiation field in an appropriate irradiation time, online dose monitoring for irradiation control and the precise determination of the absolute particle dose delivered to the cells. All components
and methods have proven their stability and reliability in systematic studies
over months. Moreover, dose response curves have been measured for the
chosen endpoints and cell lines showing no significant differences in radiobiological response between pulsed and continuous particle beams for the vast

Guidelines and protocols in the radiotherapy department
564 speaker
STAFFING AND EQUIPMENT OF RT CENTRES: COMPARING THE
EORTC, ESTRO AND DUTCH GUIDELINES
C. Hurkmans1
1
C ATHARINA Z IEKENHUIS, Department of Radiation Oncology, Eindhoven,
Netherlands

T HURSDAY, M AY 12, 2011
Multislice CT, MRI) and functional (eg. MRS, PET/CT) imaging modalities
help in determining the target volume and organs at risk as well as assesment of organ motion. To control and compensate for the image degradation
related to motion (due to respiratory cycle) one of the most recent technological progress is a PET/CT system integrated with respiratory gated (RG)
4D-PET/CT acquisition techniques.
To fully exploit the capabilities of the IMRT treatment it is necessary to introduce and develop IGRT techniques to localize the tumor and the organs at
risk before treatment delivery and to calculate organ motion during a single
fraction as well as in the whole course of Radiotherapy. In the clinical practicethey are divided into: off-line and on-line solutions.
IGRT aims at: reduction of set-up margin - EPID, KVCBCT, MVCBCT including MVCT in helical Tomotherapy and reduction of the internal margin with
Stereoscopic KV used for gating and tumor tracking, EPIDs in combination
with an On-board kV-system, MV imaging. It also allows to estimate the tumor response and to adapt the treatment plan during the same course ofradiotherapy -adaptive radiation therapy (ART).
Due to the organ motion in the treatment plan implementation, time factor
should be taken into account, especially in case of hipofractionated radiotherapy protocols. Therefore the implementation of methods for measuring
the motion in real time such as gating and tumour tracking is crucial for future
development of IGRT.
566 speaker

Purpose: First, to compare the guidelines on staffing and equipment fromthe EORTC ROG from 2009 to the ESTRO 2005 and the Dutch 2010
guidelines. Second, to suggest a common framework for future guidelines.
Materials and methods: The guidelines and associated underlying datafrom the three surveys were analysed. For the Dutch guidelines, theguidelines were recalculated to number of patients per Full-Time-Equivalent(or per equipment unit).
Results: Both EORTC and ESTRO have based their workload definitions
on the number of patients that receive radiotherapy. The Dutch NVRO
guidelines refined the workload calculations by introducing 4 radiotherapy
complexity classes for teletherapy and 5 classes of brachytherapy. Using
this latter refinement, a more than merely patient numbers related workloadincrease could be foreseen, which stimulated timely planning of investments.
The more recent EORTC and Dutch guidelines are similar to the slightly
older ESTRO guidelines (see table). However, an increase of throughput for
CT scanners/simulators is foreseen, reflecting the increased replacement of
conventional simulators by time efficient CT scanners. The ESTRO guidelines are based on a survey of national guidelines, whereas the EORTC and
Dutch guidelines are based on actual infrastructure information. Although all
three surveys collected data on technologist staffing and treatment planningequipment, no guidelines were formulated for these important topics by the
ESTRO and the EORTC. However, minimum requirements have been set in
the EORTC and Dutch (in brackets) guidelines as follows: MV units: 2 (4);radiation oncologists: 3 (8); and clinical physicists: 2 (3). IT-specialists: - (1.5)

Conclusion: The various guidelines are reasonably similar but figures fortechnologists and infrastructure other than MV units are missing. The suggested set ofminimum facility requirements for a department varies muchmore, reflecting the huge variance throughout Europe. Overall, there exists a need for more comprehensive guidelines that closely follow trends intechnology and workload.
565 speaker
USE OF PRE-TREATMENT IMAGING PROTOCOLS FOR MOTION
ESTIMATION
B. Bak1
1
G REATER P OLAND C ANCER C ENTRE, 2nd Radiotherapy Department,
Poznan, Poland
Modern techniques of the imaging and dose delivering during irradiation allow
to separate the tumor volume from normal tissue with almost surgical precision. This allow for the reduction in treatment toxicity with the potential fordose escalation and thus improved tumour control. Precision and accuracyof our actions becomes crucial so it is necessary to carefully define target
volume and to precisely deliver the daily treatment.
Currently the standard method of imaging for the treatment planning process
is the CT. Continuous evolution including improvements in morphological (eg.

THE IMPACT OF RECTAL AND BLADDER PREPARATION IN
PROSTATE RADIOTHERAPY
L. Mullaney1 , P. Thirion2 , M. Coffey3
1

SLRON S T. J AMES ’ S H OSPITAL, Department of Radiation Oncology,
Dublin, Ireland Republic of
SLRON S T. L UKE ’ S H OSPITAL, Department of Radiation Oncology
3
T RINITY C ENTRE FOR H EALTH S CIENCES, Division of Radiation Therapy,
Dublin 8, Ireland Republic of2

Purpose/Objective: Patients’ anatomy can vary during a course of fractionated prostate radiotherapy resulting in a lower than intended dose to theprostate and a greater than intended dose to the OARs. The purpose of thisresearch is to recommend a suitable rectal and bladder preparation protocolthat would achieve a consistent rectal volume (RV) and bladder volume (BV)
and minimise prostate displacement.
Material/Methods: Forty 3DCRT prostate patients treated using cone beam
CT imaging were enrolled in the study. Twenty patients were assigned to no
specific rectal preparation instructions (NRP arm) and twenty patients wereassigned to a rectal preparation (RP arm) protocol. This protocol consistedof a low fibre, anti-flatulence diet and laxative (30ml Milk of Magnesia), as
required. Within these arms, patients were randomly assigned to one oftwo bladder filling protocols (1080ml or 540ml of water, 30-40mins prior totreatment). Having completed a bony registration, prostate displacement wasmeasured using a bounding box technique. RV and BV were assessed, as
was GI and GU toxicity. For the bladder filling aspect of the study patient
comfort was also assessed.
Results: For the 40 patients a total of 363 scans were reviewed. The NRP
arm reported significantly less prostate displacement at the left (p=0.015) andinferior prostate border (p=0.009) when compared to the RP arm. However
for both arms, the mean prostate displacement at these borders (<5mm) were
within the PTV margin; therefore not clinically significant. The RP arm hadsignificantly less RV variation when compared with the NRP arm (p=0.048).
There was no significant difference in prostate displacement or BV variation
between the bladder filling arms. The 540ml arm was reported marginallymore comfortable than the 1080ml arm. Both arms in the rectal preparation
and bladder filling protocols were comparable in terms of acute and late toxicity. For the forty patients, there was a correlation between the BV variationand displacement of the superior prostate border (r= -0.39; p= 0.01; n=40)
and RV variation and displacement of the posterior prostate border (r= 0.55;
p=0.002; n=40). The correlation between the posterior prostate border andRV variation did not hold true when the NRP arm was investigated in isolation.
Conclusion: The RP protocol and 540ml of water bladder filling protocol resulted in prostate displacement of <5mm and achieved consistent RV and BV
throughout a course of radiotherapy.

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ESTRO-ESGO Joint symposium: Gynecological
Cancer - Vision for the future: What ‘we’ will ask
for in the new grant applications? - Translational
research / high technology
567 speaker
ANTIVIRAL APPROACHES TO TREAT HPV RELATED TUMORS :THE INSTITUTE GUSTAVE ROUSSY EXPERIENCE FROM PRECLINICAL DATA TO CLINICAL TRIALS
E. Deutsch12 , M. C. Vozenin-Brotons1 , P. Morice3 , C. Lhommé4 , P.
Pautier4 , M. Deberne1 , J. C. Soria4 , C. Haie-Meder2 , J. Bourhis21
1
INSERM 1030, Radiobiology, Villejuif, France
2
I NSTITUT G USTAVE R OUSSY, Radiation Oncology, Villejuif, France
3
I NSTITUT G USTAVE R OUSSY, Surgery, Villejuif, France
4
I NSTITUT G USTAVE R OUSSY, Medicine, Villejuif, France
The knowledge of high risk HPV implication in a significant proportion ofsquamous cell carcinoma of the cervix, anus, head and neck raises thequestion of biologically-driven therapeutic approaches for these tumors(1, 2). Large scale anti HPV vaccination will require at least one or two
decades before affecting incidence of HPV-relative cancers.
Despiteimprovements in survival and local control due to concomittant administrationof radiotherapy and chemotherapy in cervix tumors due to conconcomittant
chemoradiation and opitmisation of brachytherapy, the treatment of locallyadvanced tumors remains a challenge. We have developed an original
approach aiming at sensitizing HPV related tumors to ionizing radiation andchemotherapy using an antiviral agent Cidofovir. Cidofovir is a nucleosideanalog. Combination of Cidofovir increase radiation sensitivity in vitro andin vivo. Of interest, preclinical findings suggests that this radiosensitizing
effect is HPV dependant, suggesting a tumor relative specificity in the clinic.
Exposure to Cidofovir indeed correlates with a decrease in HPV related
oncoproteins and a restauration of the tumor suppressor protein levels
p53 and pRB (3). In addition, exposure to cidofovir is associated with asharp decline in metastatic potential, reflecting the inhibitory effects on the
cxcr4/SDF1 chemotactism as well as a restoration of the p53 inhibition on
VEGF. We also found that Cidofovir can also exert synergistic cell killing in
combination with antiEGFR targeted agents. Cidofovir is and antiviral agent
approved for the treatment of CMV retinitis, its main dose limiting toxicity isrenal. We have initiated a clinical trial in order to assess the safety of theaddition of Cidofovir to chemoradiation and brachytherapy. Carboplatinum
has been used along with hyperhydratation and probenecide in order tominimize synergistic nephrotocity. Patients with locally advanced cervicaltumors, with evidence of HPV infection on tumor biopsy and/or pap smear
are included into this trial. So far, 3 out of the four dose levels of Cidofovir
have been achieved. No dose limiting toxicities were observed and the lastdose level should be completed in 2011. We will present the preliminary datafrom this trial as well as the approach developed at Institute Gustave Roussy
for the treatment of HPV related malignancies.
1. Vozenin, Deutsch et al What Have We Learned From Human
Papillomavirus-Positive Tumors? Trying to Connect Data About
Biomarkers Among Human Papillomavirus-Related Squamous Cell
Carcinomas. J Clin Oncol. 2010
2. Vozenin, Deutsch et al. Unravelling the biology of human papillomavirus (HPV) related tumours to enhance their radiosensitivity. Cancer Treat Rev. 2010.
3. Abdulkarim et al. Antiviral agent Cidofovirrestores p53 function andenhances the radiosensitivity in HPV-associated cancers. Oncogene.
2002
4. Amine, Bourhis , Deutsch, Vozenin-Brotons. Novel anti-metastatic
action of cidofovir mediated by inhibition of E6/E7, CXCR4 andRho/ROCK signaling in HPV tumor cells. PLoS One. 2009568 speaker
CERVIX CANCER: TECHNOLOGY, TRANSLATIONAL AND CLINICALRESEARCH
R. Pötter1
1
M EDICAL U NIVERSITY V IENNA , AKH, Radiation Oncology, Vienna, Austria
After the introduction of chemoradiation into standard of care in 1999, theevolution of Image Guided (Adaptive) Radiotherapy during the last decade
has widened the research avenue for improvement of cervix cancer treatment
with significant progress to be expected from technology orientated clinical research. This treatment improvement research pathway is to be understood inS 232

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T HURSDAY, M AY 12, 2011

parallel with other important areas as HPV vaccination and screening whichhave been and will be changing the clinical scenario, mainly in the westernworld and partly outside. The global impact of systematic screening and vaccination programmes can only be expected after many decades and aftersome global economic and social "revolution".
It seems therefore necessary to invest into treatment improvement researchin a major female cancer with ~473.000 new cases and ~253.000 deaths per
year worldwide (increasing), also or in particular, when a large proportion ofthese women live in regions with limited resources.
Image Guided Adaptive BrachyTherapy (IGABT), based mainly on MRI (CT)at present is just leaving its pioneer phase with first prospective multicenter
data starting to come up now and during the next years: STIC, RetroEMBRACE, EMBRACE. The major clinical results will likely refer mainly to control
and reduction of treatment related morbidity and to improvement of local control, maybe associated with improvement of survival. It can be expected that
there will be a next generation of hypothesis driven clinical trials asking specific questions within phase III trials, e.g. on dose escalation/de-escalation.
For EBRT large variations for tumour and OAR during chemoradiation havebeen reported based on repetitive imaging studies. Adaptive IGRT protocols
based on IMRT will be developed applying advanced target concepts within
specific clinical settings. Such IGART will aim mainly at a reduction of morbidity and at dose escalation in specific lymph node areas at risk.
The value of imaging will be further elaborated and clarified both for IGABT(tumour) and IGART (lymph node areas). The concept of adaptive target definition (HR CTV) will have to be validated and analogue concepts to be developed for IGART which have to be further elaborated by (functional) imaging((USPIO) MRI, PET). For IGABT the role of CT associated with MRI will haveto be clarified.
As cervix cancer is a major disease in regions with limited resources, low cost
imaging and treatment technologies will become important areas of R&D for
IGABT. Therefore, besides CT imaging, US imaging to be also proven as
clinically not too far inferior to MRI - and US based adaptive brachytherapy
technologies are worthwhile to be further developed (see prostate US guidedBT), which include the advantage of interactive application guidance.
Image based adaptive treatment planning (technology) will become more validated with evidence based clinically relevant DVH parameters together withspatial allocations of specific regions of interest, which applies for all CTVs
and OARs, in BT and EBRT. This will be based on 4D local/regional failure
and morbidity analysis in prospective settings like EMBRACE. The various
uncertainty issues which have been recently addressed both for IGABT and
IGART will be further elucidated.
The underlying models as suggested by the GEC ESTRO Recommendations
including the "worst case assumption" dose reporting model and the "linearquadratic" model for BT effects will become further elaborated based on alarge clinical data set (EMBRACE/RetroEMBRACE).
DVH parameters for tumour and OAR and their biological modelling will haveto be investigated taking into account advanced biological techniques assessing individual radio-sensitivity of OAR (e.g. genome, SNPs) and tumour(radio)-biology (e.g. hypoxia, COX-2, SCC, EGFR).
Distant failure will become even more the predominant area of failure whichasks for relevant drug development and testing within clinical trials. Therefore
there seems to be a strong need to enter more intensively into the researcharea of risk stratification, which implies specific clinical scenarios with highrisks for distant spread and major research work on prognostic factors in thetranslational setting (e.g. hypoxia, COX-2, EGFR). Beside biological treatments ("targeted therapies") the adjuvant chemotherapy setting for patientswith a high risk of distant recurrence will have to be further explored.
Finally, at the very end of a long and complex R&D process a full integration of all relevant diagnostic, prognostic, predictive and treatment planning parameters should become possible which will then enable an evidence
based highly individualized risk adapted overall treatment strategy combining
IGART, IGABT and advanced drug treatment. 4 D integration of IGART and
IGABT will become part of this process through advanced image registration
techniques, which will further increase the safety of treatment planning anddose application.

are investigating the roles of radiotherapy and of concurrent and/or adjuvant
chemotherapy, given alone or in combinations.
Despite the risk stratification based on classical prognostic factors there still
remains considerable overtreatment. Strategies to further improve outcome
and avoid overtreatment in endometrial cancer are to 1) decrease overtreatment by using combinations of known risk factors and seek novel risk factors
to improve tailored treatment; 2) increase the efficacy of existing or novel
systemic therapies to decrease the rate of distant metastases; 3) improveexisting radiation treatment delivery techniques, maintaining efficacy while
reducing treatment related toxicity.
Two subtypes of endometrial cancer have been described: type-I endometrioid endometrial carcinoma (EEC) associated with unopposed estrogen exposure, and the less frequent type-II non-endometrioid carcinoma (NEEC;
usually papillary serous or clear cell). Evidence for divergent molecular alterations supporting this dualistic model of endometrial tumorigenesis has accumulated in the last decade. In EEC relevant molecular changes are describedin the RAS-RAF-MEK-ERK and P13-AKT signaling pathways, resulting in enhanced proliferation, transformation and cell survival. NEEC frequently show
gene alteration in p53 which results in evasion of apoptosis and genomic instability. Despite these differences, considerable overlap in clinical disease,morphology, immunohistochemical expression profile and molecular features
have been described. Most studies have focused on single genes or signaling pathways in small patient populations. Future studies will be aimed at
describing molecular risk profiles for high-grade disease, myometrial invasionand (lymph node) metastasis by studying candidate gene sets in larger patient populations with longer clinical follow-up. These molecular risk profiles
can be further tested for their capacity to improve patient-tailored treatment.
Recent developments in image-guided MRI-based 3-dimensional brachytherapy for cervical cancer have led to improved target coverage and sparing oforgans at risk. For vaginal cylinder brachytherapy (VBT) as adjuvant therapy
in endometrial carcinoma, ICRU guidelines suggest reporting tumor and organs at risk (OAR) dose points derived from two-dimensional images. A large
variation in dose and fractionation schedules have been reported, specifying
the dose at the cylinder surface or at 5 mm depth, and with target volumes
including different lengths of the vagina. Although all of these schedules werereported to be effective, most studies have included patients with a low riskof recurrence, hampering evaluation of a dose-effect relationship. Low rates
of bowel and urinary toxicity have been reported. However, various definitions of toxicity have been used in these studies, especially regarding vaginalmucosal toxicity. Since large variations in vaginal surface dose and treatedlength have been reported, dose effect relationships for tumor control andtoxicities remain uncertain.
Little is known about clinical target volume (CTV) definition for adjuvant VBTbased on 3D MRI images in the proximal part of the vagina. Future studies will focus on defining a MRI-based CTV and 3D dose volume histogram(DVH) parameters of both CTV and OAR, in order to establish more precise
estimates of dose effect relationships.
The total dose used in adjuvant VBT is relative low, with low exposure of thegastrointestinal and urinary organs, explaining the low toxicity rates. When
VBT is given as a boost after external beam radiotherapy or as retreatment
for recurrent disease, higher total doses in OAR and higher toxicity rates arereported. Brachytherapy in the setting of primary treatment or retreatment forrecurrent disease is far less frequently applied than in the postoperative adjuvant setting and existing studies report two-dimensional dose points. Futurestudies will focus on using 3D MRI-based brachytherapy to establish doseeffect relationships for both tumor and OAR in the setting of recurrent disease.

569 speaker

Abstract not received.

TECHNOLOGICAL DEVELOPMENTS AND TRANSLATIONAL RESEARCH IN ENDOMETRIAL CANCER TREATMENT: MOLECULARDATA AND IMAGE GUIDANCE
R. Nout1
1
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Radiation Oncology,
Leiden, Netherlands
In view of the good prognosis of the majority of endometrial cancer patients,
adjuvant treatment is risk-based and tailored to well established prognostic
factors based on clinical and pathologic studies. Strongest prognostic factors
are stage, histologic subtype, tumor grade, depth of myometrial invasion, age,and lymph-vascular space invasion. Patients with a (high-)intermediate risk
profile, approximately 30% of all patients, are predominantly at risk of local
recurrence at the vaginal vault. For these patients, vaginal brachytherapy has
been shown to ensure a high probability (98%) of vaginal control, and is associated with less gastrointestinal symptoms and a better QoL than externalbeam radiotherapy. For patients with high-risk disease (15%), current trials

570 speaker
WHAT’S NEW IN SENTINEL LYMPH NODE DETECTION IN VULVARCANCER
A. van der Zee1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN, Gynaecology, Groningen,
Netherlands

T HURSDAY, M AY 12, 2011

ESTRO-EANM Joint Symposium: Imaging
571 speaker
PET IN ONCOLOGY IN 2011: A REVIEW OF THE EQUIPMENTS,
TRACERS, INDICATIONS, OVER THE LAST 10-20 YEARSW. Vogel1
1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

Abstract not received.

572 speaker
PET IN RADIATION ONCOLOGY IN 2011: WHERE ARE WE? USE OF
DIFFERENT PET RADIOPHARMACEUTICAL FOR TARGET VOLUME
SELECTION AND DELINEATION
A. Chiti1
1
I STITUTO C LINICO H UMANITAS, Nuclear Medicine, Rozzano (Milan), Italy
Purpose: This contribution is intended to be an overview of the possible applications of radiopharmaceuticals different from 18F-FDG in the target volume selection and delineation.
Methods: The availability of radiopharmaceuticals able to image several
metabolic pathways allowed to overcome the limitation of FDG, due to its
biodistribution and to the fact that some tumors are characterized by a low
glucose consumption.
Data from the available literature are illustrated and summarized, taking into
account in particular the recently published special issue of Radiation andOncology, dealing with the use of PET in radiation treatment planning.
Results: An increasing number of papers are being published on these topics and clinical results are already available.
Conclusions: Positron Emission Tomography is going to be increasingly
used in radiation treatment planning, thanks to the wide range of radiopharmaceuticals available.
573 speaker
PET IN RADIATION ONCOLOGY IN THE NEAR FUTURE: WHERE
ARE WE GOING TO?
X. Geets1
1
C LINIQUES U NIVERSITAIRES S AINT L UC, IMRE, Brussels, Belgium
Positron Emission Tomography (PET) has been playing a growing role in various domains of oncology such as cancer diagnosis, staging and therapeutic
evaluation for years. In radiation therapy, PET has also provided a uniquetool for the non-invasive molecular characterization of the tumor biology thatmight further be exploited for individually adapting treatment approaches. In
this regard, the PET 3D mapping of phenotypic tumor characteristics known
to affect the clinical response to radiation, such as metabolism or hypoxia,
might first be used for redistributing or escalating the dose to the target in abinary or gradual way using dose-painting strategies. Secondly, PET mightbring essential information to the available molecular data to establish a predictive signature of individual tumor response. This would help at adjusting
the treatment regimen accordingly by modifying the delivered drugs, the total
radiation dose and/or the dose fractionation, at the time when further treatment improvements may still be expected.
Although promising, this exquisite personalization of treatment will still require
intense efforts from research teams in the coming years to become a clinicalreality. From the biological point of view, additional works should focus on theidentification by PET of functional tumor parameters of interest that unequivocally correlate with the patient outcome. For each of these parameters, theoptimal tracer, i.e. highly sensitive and specific, and optimal image acquisition
settings (static vs dynamic acquisition, timing of acquisition) should then be(re)defined. Finally, TCP models would be derived from the imaging data, andthus would ultimately drive heterogeneous dose prescriptions to get a uniform
density of clonogen surviving. Encouragingly, evidences already exist about
the radioresistant effect of high tumor FDG uptake and the technical feasibility of redistributing radiation doses. Based on these observations, PET-driven
dose-escalation trials were recently designed in HNSCC and NSCLC. Theseongoing studies are expected to shortly confirm the added value of such approaches in terms of both local tumor control rates and patient survival. At
the same time, the emergence of new tracers such as radiolabeled antibodies, will certainly participate at the global, in vivo detection of the receptor
status that correlate with particular tumor phenotypes, with the purpose of
better selecting patients who would benefit from targeted therapies.
Another important issue that has to be quickly addressed concerns the unfavorable physical characteristics of the PET system, i.e. its poor spatial resolution and limited statistics. Indeed, the PET images are blurred and noisy,

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both effects preventing the precise identification of the tumor regions boundaries. If many delineation methods have already been developed to assist
the radiation oncologist in this task, the most accurate and robust technique
has not yet been identified. Expert research teams are currently joining theireffort to define large, high-quality validation data sets from which the optimal segmentation would probably emerge, and made widely available amongradiation centers. Along these lines, companies are hardly working on thedevelopment of high-resolution and combined multi-parametric imaging systems that would reduce both partial volume and tissue fraction effects (PVE
TFE), that would provide a larger range of morphological and functional information about the tumor, and that might thus serve as a more reliable basis
for biologically-adapted strategies.
As a conclusion, intensive technologic developments in radiation delivery
techniques, imaging, computational and biology, offer new opportunities toin-depth modify the way the treatment is designed and the dose delivered,in accordance with the radiobiology of cancers. If the 2000’s were theyears of emerging concepts, the 2010’s should come to clinical realities bymeans of additional technical refinements and clinical trials. Hopefully, thebiologically-driven dose prescriptions should soon offer to our patients optimized complication-free tumor control.

How to meet the needs for QA in adaptive radiotherapy?
574 speaker
ECONOMIC BURDEN OF QA IN ADVANCED RADIOTHERAPY
Y. Lievens1
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Radiation Oncology, Leuven,
Belgium
The rapid diffusion of technology has been identified as one of the most important factors driving the escalating health care expenses. In the field of radiotherapy, new imaging and information-communication opportunities alongwith the technical improvement of radiotherapy equipment have all had a considerable impact on the accuracy of the treatments we deliver. Unfortunately,
there is no free lunch: higher accuracy came with higher complexity, hencecosts. Moreover, the better dose conformity has made the precision of treatment delivery more critical, thus the need for more quality assurance before
and during treatment.
Only few studies inform us on the cost of radiotherapy, and more specifically, on the evolution of radiotherapy cost over time with evolving technology. Already ten years ago, the Swedish Council of Technology Assessment
in Health Care calculated a 16% increase in cost between 1991 and 2000.
More recently, a Canadian overview estimated the annual cost increase at
the radiotherapy treatment level at roughly 5%. These data however all refer to techniques of the nineties, that is, before the wide introduction of noveland more complex approaches such as intensity-modulated, stereotactic andimage-guided radiotherapy, only to name a few.
There is only limited evidence on the actual cost implications of these techniques and of their associated quality assurance. Depending on the typeof pathology, treatment complexity, fractionation schedule and the required
quality control, cost increases compared to ’standard’ three-dimensional radiotherapy have been reported to vary between 30 and 100%. Even moredifficult is it to appraise their value for money, and not only because of the
difficulty to compute the costs. The principal difficulty with which one is facedin performing cost-effectiveness evaluation on quality-improving activities inradiotherapy, is to value their incremental impact on outcome. Lacking longterm effectiveness data, we can at best rely on improved dose-distribution,
which can then be assumed to translate into a better outcome in a later sometimes much later stage.
The scarcity in available evidence stresses the difficulty of evaluating thecost(-effectiveness) of novel, evolving technologies, with the subsequent riskthat they will become obsolete even before this evidence has formally beenobtained. It is however imperative that the radiotherapy community starts investing in this type of research: the comparison of computed cost data withreimbursement levels frequently demonstrates an imbalance in disfavor of income. Which in turn may slow down the implementation of quality-improving
innovations.
Having recognized the importance of this, ESTRO is now launching the
HERO (Health Economics in Radiation Oncology) project, which will focus
on the needs and accessibility, on the cost and cost-effectiveness of radiotherapy in the European context.
575 speaker
REPLACING QA MEASUREMENTS BY CALCULATIONS?
J. Olofsson1
U MEÅ U NIVERSITY, Department of Radiation Sciences, Umeå, Sweden

1

Quality assurance (QA) is, for good reasons, an important part of the radiation

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therapy process. Looking at the variety of QA tools that has become available
along with the clinical introduction of intensity modulated radiotherapy (IMRT)
one can draw the conclusion that dose verification based on measurements
is a very common practice. But is it really necessary to perform QA measurements on each individual IMRT plan in order to maintain patient safety? The
tradition is, quite opposite, to restrict QA measurements to pure accelerator/beam properties and to instead verify individual treatment plans by some
non-experimental inspection procedure. The reason for this approach has
obviously been to minimize the fraction of accelerator/beam time used for QA
instead of treatments.
The complexity of state-of-the-art treatment plans, categorized as IMRT, IMATor Adaptive, certainly increases the level of expertise required for designingand performing adequate QA. In our opinion it should, however, be possible
to ensure patient safety without having to retreat into always delivering theactual treatment beams prior to the first treatment. The potential benefits are:
1. Reduced workload for QA, 2. A more flexible QA process that can be
fine-tuned for each clinic, 3. Improved accuracy through more sensitive QA
methods. But it also requires an extensive analysis of the process that results
in a patient receiving advanced radiation therapy.
One important part of the treatment plan inspection is the independent dose
calculation (IDC). Old factor-based dose/MU calculation methods must be replaced by modern model-based algorithms that can handle treatments madeup by small and dynamic beams. Another important aspect of IDC that should
be further explored is how to set up action limits for deviations and how to use
them. Deviations outside the action limits must be investigated to avoid erroneous treatments, but how should one consider deviations inside the actionlevels? By introducing tools for statistical analysis of these deviations there isa potential to learn more and to refine the clinical dose calculation methods
used today.
576 speaker
PATIENT-SPECIFIC QA FOR ADAPTIVE RADIOTHERAPY
W. van Elmpt1
1
MAASTRO C LINIC, Department of Medical Physics, Maastricht, Netherlands

Current clinical procedures used in patient-specific Quality Assurance (QA)
which are necessary to verify complex patient treatments are discussed.
QA procedures should focus on imaging (patient geometry, positioning andtarget verification) and dosimetry (e.g. target dose coverage, in vivo dosimetry). The recent introduction of IMRT and volumetric modulated arc therapy
for a wide variety of treatment sites has increased the necessity of QA procedures. With the current interest of the society in adaptive radiotherapy, QA
procedures might have to be adjusted for this purpose.
This talk will focus both on the current standard procedures available for QA
of radiotherapy treatments and discuss the suitability to use these methods
in the context of complex radiotherapy treatment and adaptive radiotherapy.
For imaging, cone-beam CT is frequently used to align the patient using theplanning CT as a reference and advanced strategies are based on imaging
features (e.g. dose-painting or geometry adapted treatment planning). For
dosimetry, the most frequent used verification strategies are performed pretreatment comparing a measured dose in a phantom or delivered to a 2D
detector. For in vivo dosimetry purposes, commonly used techniques withsingle point dose measurements (e.g. diodes) have become less popularand less effective for advanced therapy techniques. New strategies basedon the measured 2D and 3D dose during treatment either with specialized
detectors or using electronic portal imaging devices have become available.
These techniques are ideally suited to be implemented for these treatments.
Strategies for performing quality assurance in external beam therapy havechanged over the last decade. In the upcoming decade, adaptive radiotherapy procedures will increase the complexity of treatments. Quality assurance
procedures need to keep up to maintain the high level of quality achieved incurrent radiotherapy procedures.

T HURSDAY, M AY 12, 2011activities.
Education and Training: Common education and training goals across Europe would go a long way towards enhancing mobility of professionals including medical physicists. The Council of EFOMP at its September 2008 meetingin Krakow set in motion the ’Tuning of Educational Structures in Europe’ process for Masters’ programs in Medical Physics in Europe. For the medical
physics profession a fundamental component of Tuning would be the setting
up of an inventory of agreed pan-European learning outcome competences
for such programs. This would represent the minimum set of competencesthat a student should acquire at the exit point of the program. One of the tangible outcomes of this process has been the convergence of Education andTraining syllabi in both Diagnostic Radiology and Radiotherapy with Nuclear
Medicine following closely. These documents now not only contain the knowledge required of a practitioner, but also provide an overview of the practicalskills and competencies which are essential to a Medical Physicist. In addition, EFOMP has recently issued Policy Statement 12 : "The Present Statusof Medical Physics Education and Training in Europe. New perspectives and
EFOMP Recommendations." This document provides minimum standards ofEducation and Training required of medical physicists and is closely alignedwith the syllabi.
Accreditation of Medical Physics Education and Training Programs:
EFOMP issued policy statement No.6 "Recommended guidelines of National
Registration Schemes for Medical Physicists" in 1994. This policy statement
aims firstly to stimulate countries to establish a Registration Scheme for Medical Physics and secondly, to harmonise the requirements to become a registered physicist. To date 11 countries have their Registration scheme evaluated by EFOMP. Currently, the scheme is somewhat of a paper exercise which
validates that the country has 1) minimum standard of education required 2)
training assessment for the medical physicist and 3) the presence of CPD
program. EFOMP is currently reviewing ways to strengthen the scheme toincrease its credibility and an update will be given on this.
European Network of Medical Physics Schools: EFOMP considers Continuing Professional Development a critical component of the professional responsibilities of the Medical Physicist. It has in fact issued a Policy Statement on this (No.8, 1997). IT should be noted that a considerable numberof courses and workshops now apply for EFOMP CPD credits. This ensurescompatibility of standards across Europe. TO expand on this, EFOMP iscurrently working towards a "European Network of Medical Physics Schools
which should become a future Core of Knowledge for the Medical Physicist.
EFOMP would consider such a School to consist of a number of components: firstly a repository and calendar of Courses which would qualify for EFOMP
CPD credits. Secondly, it would also include a repository of post-graduate
education courses (both Diploma and MSc level) which should allow a medical physicist from one country to easily choose a course in another country
should he/she so desire. Finally, we envisage that ENMPS would also include
physical schools and institutions, where individuals can obtain practical training. An update on the progress of the ENMPS will be given.
Medical Physics Expert Project: European Directive 96/29/Euratom and97/43/Euratom introduced the definition of the Qualified Expert in Radiation
Protection (QERP) and the Medical Physics Expert (MPE) respectively. The
function of a QERP has been introduced in most countries as that of the Radiation Protection Advisor. However, this has not happened with the Medical
Physics Expert. Within the re-writing of the European Directives on Radiation
Protection it became obvious that there was a considerable difference within
individual countries within Europe on what constitutes an MPE. To clarify thisand to provide guidance, the Commission issued a tender for a project to 1)
provide a working and operational definition of MPE 2) review the status oftraining and education of MPEs across Europe and 3) conduct surveys on
the number of physicists and the actual roles which are performed by MPEs.
The project is scheduled to be completed late 2011 and this presentation will
provide an update on the status of the project.
Summary: It is gratifying that in an increasing number of countries in Europe, the profession of Medical Physicist has become one which is regulated
under law. EFOMP has a critical role to play to ensure that such necessaryregulation, does not become an unnecessary barrier to mobility.
578 speaker

Mobility of medical physicists in the world
577 speaker
THE MOBILITY OF MEDICAL PHYSICISTS IN EUROPE. ROLE OF
EFOMP
W. van der Putten1
1
E UROPEAN F EDERATION OF O RGANISATIONS OF M EDICAL P HYSICS, York,
United Kingdom
Purpose: One of the guiding principles of the European Community is freedom of movement of the citizens of the individual member states. Although
this is not a major problem for ordinary relocation, it is a problem where theprofession of the individual is regulated in a member state. This is the casefor Medical Physics in a number of countries. From its’ inception, EFOMP has
been involved in activities which aim to increase the mobility of the Medical
Physicist in Europe. This presentation will give an overview of some of these

AAPM: STANDARDIZED APPROACH TO SUPPORT QUALITY AND
MOBILITY IN MEDICAL PHYSICS
B. Paliwal1
1
U NIV. OF W ISCONSIN S CHOOL OF M EDICINE AND P UBLIC H, Departmentof Medical Physics, Madison WI, USA
Abstract not received.

T HURSDAY, M AY 12, 2011579 speaker
IOMP: GLOBAL APPROACH TO SUPPORT MOBILITY OF MEDICALPHYSICISTS
M. D. C. Lopes1
1

I NSTITUTO P ORTUGUÊS DE O NCOLOGIA C OIMBRA - F RANCISCO G ENTIL ,EPE, Medical Physics, Coimbra, Portugal

Introduction: The International Organization for Medical Physics (IOMP)
was formed in January 1963 initially with 4 affiliated national member organizations. The Organization has continuously grown to a membership in year
2010 of 80 national member organizations and 6 regional organizations representing more than 18000 medical physicists worldwide.
IOMP is charged with a mission to advance medical physics practice worldwide by disseminating scientific and technical information, fostering the educational and professional development of medical physics and promoting thehighest quality medical services for patients.
In a basic approach, mobility is facilitated by IOMP through support and sponsorship for international conferences and symposiums in medical physics.
IOMP provides some travel assistance for medical physicists from developing
countries to attend international conferences and training courses in medical
physics.
In a deeper approach, harmonization of standards for education, training andprofessional development is the keyword for mobility of professionals contributing to elevate the profession globally so that available skills and knowledge can be equitably distributed in all countries.
Education, Training and Professional Development of Medical Physicists: To provide guidance on professional development of medical physicists, IOMP is publishing a policy document on their role and responsibilities
meeting the global worries for strengthening medical physics knowledge andcompetencies towards safer practices for patients and professionals.
In order to carry out the roles and responsibilities a medical physicist must be
fully qualified to work independently.
IOMP is also publishing a policy statement that provides guidance and requirements on education and training of medical physicists. The two key
points of the requirements are: i) demonstrating competency by appropriate education and clinical training; ii) obligation to participate in a continual
professional development program.
A Model Curriculum for Medical Physics Education is being developed as an
IOMP E&T Committee (ETC) project initiated during 2006. It aims to provide
guidance on entry requirements, structure of the curriculum model of teaching, number of teaching and self-learning hours, student projects and dissertations, assessment of students, accreditation of the program, etc. A Validation and Accreditation Panel (VAP) was also established under the ETC. This
sub-committee could not only assess and validate the programs, but could
also provide external examiners and suggest suitable lecturers to serve small
countries.
Professional recognition of medical physicists with clinical responsibilities isa corollary of proper education and training and includes two levels of approach: validation and accreditation of MSc. Courses and certification of
professionals through a national or international body.
IOMP recommends that as a quality assurance measure on standard of practice all MPs working as health professionals should be subject to professional
certification. A task group has been established to explore the possibilities of
implementation on a global basis of a system of professional certification for
medical physicists.
Professional competency should be maintained through the implementationof a mandatory CPD scheme (national or external).
International Cooperation: IOMP is collaborating on a variety of medical
physics issues with national and international organizations like IAEA, WHO
and IRPA. A common concern is that the quality of patient care and patient
safety should be the same in every country.
Specific initiatives concerning Low and Medium Income countries (LMI) havebeen taken for the last decades. Since 1992, IOMP has co-sponsored with
AAPM the International Scientific Exchange Program (ISEP) which is held
on an annual basis to provided training to medical physicists in developing
countries. IOMP is also collaborating with AAPM and other national member
organizations in developed countries under the Library and Equipment Donation Programs.
Recently, the idea of an ’International Centre for Medical Physics’ to be established in a LMI country has been proposed. The centre would have a permanent scientific staff but visiting scientists would be encouraged to spend
sabbaticals at the centre or to be seconded to it. The main roles of the centre
would be research, development, education and professional advice.
Conclusion: Mobility is facilitated by harmonized education and training
standards, which is a prerequisite to improve the quality of the profession,
to raise the professional status and to ensure best clinical outcome. The
unwanted consequence of mobility is "brain drain". This is a delicate issue
that should not be forgotten by international organizations when designing
supporting programs and initiatives. It is a real concern that affects many
professions and Medical Physics is not an exception.
Maria do Carmo Lopes is currently the Chair of the Education and Training
Committee in IOMP.

S YMPOSIUM

S 235

Improving delivery accuracy by using in-room
imaging
580 speaker
CONE BEAM CT FOR USE IN DAILY CLINICAL ROUTINE: AN
UPDATE
C. Machado1 , C. Miguel1 , A. Martins1 , C. Cerqueira1 , D. Cardoso1
1
H OSPITAL DA L UZ, Radiotherapy Department, Lisbon, Portugal
Modern radiotherapy techniques demand modern imaging approaches. Conebeam CT, allowed improved efficiency in conventional treatments and encouraged the implementation of state of the art delivery techniques.
Advanced treatment delivery requires lowering the risk of misplacing plannedtarget volumes or critical structures. The level of confidence is determined by
the quality of anatomical imaging technique. 3D visualisation and image guidance, give the possibility to reduce planned-treated differences and restrict
daily set-up variation. Also allows the reduction of unnecessary irradiatedtissue when location, movement and dimension of targets are determined,
therefore adopt more efficient dose regimes.
Imaging protocols, using cone beam CT, are still being studied regarding dose
exposure to the patient, image resolution, matching algorithms and workflow
issues. The optimisation of these parameters is an important guide towards
the decision of implementing new treatment techniques in a radiotherapy center. Integrated KV/MV CBCT imaging LINACs made possible to achieve verysatisfactory workflow parameters. The various software and hardware options provide efficient time consuming values and its versatility allows a wide
anatomical application.
This lecture will consist in summarising our current knowledge and perspectives about the use of cone beam CT after include it in our daily clinical routine. It will give emphasis to practical considerations on currently applied
protocols and their relevance in each delivery technique and treatment site.
581 speaker
OPTIMIZING SETUP MARGINS BY USING ON-LINE/OFF-LINE
VERIFICATION PROTOCOLS
F. Moura12
1
H OSPITAL C UF D ESCOBERTAS, Lisboa, Portugal
2
E SCOLA S UPERIOR DE T ECNOLOGIA DA S AUDE DE L ISBOA, Lisboa,
Portugal
Why using verification protocols?
Using verification protocols on the treatment routine allows the optimizationof different techniques and procedures which takes an important role on thecharacterization of setup variations. The trend of setup error vectors is crucial
on defining setup margins and guarantees that clinical target volume (CTV)and organs at risk (OARs) receives the planned dose. Treatment quality
assurance is the main issue for measure and correct deviations from theplanned dose in a reference image set (i.e. Computerize Tomography) todaily patient setup and organs motion.
On-Line/Off-Line protocols define the correction action level and decision
making by means the time on which verification is validated and applied. The
Workload and Expertise by using in-room verification systems (e.g. Portal Image, kV/Mv CT, kV/Mv CBCT, MRI, ultrasounds, optical guidance), will define
the accuracy and type of verification protocol in different treatment scenarios.
Depending on the treatment site, method of immobilization and technical procedures (including the type of verification systems) verification protocols are
more or less effective and should be used to improve setup accuracy andsetup margins optimization.
On-line correction protocols are mainly used for reduction of both systematicand random errors, but it could increase the daily setup time and the prescribed dose to surrounding tissues if localization images are made. With
off-line protocols, the aim is to reduce the systematic setup error, which normally uses the statistical data available for specific patient treatment group
and all in-room setup verifications applied for each individual patient.
The sources of random and systematic population-based setup errors canbe distinguished. These mainly concern to mechanical faults, patient related
mobility and individual radiation therapist (RTT) related setup accuracy, as
well as the time available to setup the patient. The accuracy can also be influenced by physical and mental state of the patient.
Both on-line and off-line protocols could be applied to guarantee the best
achievable daily treatment setup, either together or alone, which can leadto setup margins reduction and dose escalation for better tumor control andtreatment outcomes.
With the recent developments on treatment setup optimization, several studies have been made to achieve better understanding on how these protocols
can influence the planned doses, which will be reviewed and compared withour clinical findings.

S 236D EBATE582 speaker
ADAPTIVE TREATMENT WITH HI-ART TOMOTHERAPY FOR
LOCALLY ADVANCED HEAD AND NECK SQUAMOUS CELL CARCINOMA
F. Carruthers1 , J. A. Lee2 , R. Lhommel3 , V. Grégoire4
1
UCL C LINIQUES U NIV. S T.L UC, Radiation Oncology, Brussels, Belgium
2
U NIVERSITÉ C ATHOLIQUE DE L OUVAIN, Center for Molecular Imaging andExperimental Radiotherapy , Louvain-la-Neuve, Belgium
3
C LINIQUES U NIVERSITAIRES S AINT L UC, Department of Nuclear Medicine,
Brussels, Belgium
4
UCL C LINIQUES U NIV. S T.L UC, Department of Radiation Oncology,
Brussels, Belgium
Purpose/ Objective: As a Radiation Oncology department one always
strives to achieve treatment closest to the plan created for the patient; however, we are never completely certain that the dose actually delivered is exactly the one planned as patients alter shape due to weight lost and tumour
shrinkage. With the use of Tomotherapy Adaptive planning we can now see
the dose delivered on the daily MVCT imaging, and if requested eventuallyreplan the patient.
In this framework, we aimed to analyse data collected from patients treatedwith Radiation Therapy with Tomotherapy and use this to predict changes in
dosimetry over time. We aimed to compare the planned dosimetry with thedaily dose delivered and identify trends throughout treatment and between
patients. Using this information, we can then decide when, if needed, replanning must be made.
Material/methods: Patients were registered with the trial if they weredeemed to match the following criteria: a locally advanced HNSCC (T2-T4,
any N) treated by concomitant chemo-radiation therapy or EGFR radiation
therapy. The tumour needed to be 3cm or greater in size when seen on CT
or MR images. Patients received 70Gy in 35 fractions at 5 per week withchemotherapy in weeks 1, 4 and 7 (or daily EGFR inhibitors). Patient followed the normal pre-treatment imaging series and then had a daily highquality MVCT on the Tomotherapy machine; scanned from base of skull toclavicles, these images were used in conjunction with dosimetry information
to predict the trends in the radiation therapy treatment.
Imaging matching was performed between the Kv planning series and the
MVCT daily images. The Tomotherapy Adaptive Planning System was used,
and with current deformation software, showed the change of both tumour
volumes and critical structures; this was validated against contoured volumes
seen on KvCT imaging. The deformation software showed planned contours
deformed on MVCT taking into account patient positioning and weight loss.
Daily dosimetry was analysed and deviations from the original plan wererecorded and rated against acceptable changes throughout the treatment.
Results: Data from 9 patients were collected and analysed so far out of the
25 patients planned for the study. Dosimetric values for all tumour volumes(TV) and the deviation from the planned values were recorded. Organs at
risk (OAR) recorded were Spinal Cord (SC), Right and Left Parotid and Oral
Cavity as these were common to all tumour positions. Changes of more than
5% from the plan for the TV and of more than 3% for OARs were considered
to be outside acceptable deviations from planned dosimetry. The adaptive
software showed the trend of dose given (dose summation, dose per fraction,mean and maximums dose received by ROI) and could be used to predict the
total dose outcome compared to the intended dosimetric plan.
Preliminary results indicated that although there were changes and deviations from the intended plan of each patient, these were not systematic nor
required a complete patient replan. The deviations were, for the most part,
random and were often rectified over further fractions. So far, there has notbeen a detectable trend between patients indicating a threshold for all patients where replanning is necessary.
Conclusion: Although, the evidence so far indicated that no great deviations
from patient plans were occurring on a daily basis, further investigation isneeded. A larger cohort is required to indicate trends during treatment andbetween patients. Further data collection will reveal the need, if any, to replan
or adjust parameters in order to achieve desired dose outcomes.

T HURSDAY, M AY 12, 2011

DebateOnline transmission in vivo dosimetry renders
pre-treatment QA obsolete
583 speaker
IN FAVOUR OF THE MOTION
S. Nijsten1 , W. van Elmpt1 , F. Verhaegen1
1

MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS -TRICHT, Radiation Oncology, Maastricht, Netherlands

Purpose/Objective: Dose delivery has become more complex with the useof Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated
Arc Therapy (VMAT). The most common approach to verify these complex
treatment techniques is based on pre-treatment patient-specific quality assurance (QA). Most centers use film measurements in phantoms or specialized
2D detectors for this. Such procedures are time-consuming and do not represent the errors in patient anatomy. Hence, the delivered dose distribution ina patient could still significantly differ from the intended dose distribution. We
state that by using an on-line in vivo dosimetry procedure both the treatment
technique and the actual dose delivery to a patient could be checked simultaneously, rendering pre-treatment QA obsolete.
Materials/Methods: To verify the 3D dose delivery to a patient in vivo, both
3D imaging and 3D dose reconstruction methods based on dose measurements can be used. Imaging should be executed preferably during treatment or as close as possible before or after treatment to get an accurate 3D
anatomical patient model; dosimetry can be performed by several types of
dosimeters during treatment. We focus on the use of electronic portal imaging devices (EPIDs) to acquire both cone beam CT scans and transit portal
dose images. These objects are used in a 3D dose reconstruction procedure,
resulting in the delivered "dose-of-the-day".
Results: Different dose reconstruction strategies and approaches will be presented that can distinguish between dose delivery errors due to treatment
technique inaccuracies and patient related dose delivery errors. Sensitivity and accuracy of these methods, but also measurement times will be discussed. A comparison is made between the pre-treatment and in vivo patientspecific dose verification strategies.
Conclusions: The integration of patient-specific QA of treatment techniques
and in vivo dosimetry by using electronic portal imaging devices into one
single procedure is feasible and could render pre-treatment QA obsolete in
future. However, there is an important task for manufacturers to provide theradiotherapy community with appropriate portal dosimetry software solutions.
Procedures should also be standardized.
584 speaker
AGAINST THE MOTION
S. Kry1
1

U.T. M.D. A NDERSON C ANCER C ENTER, Houston, TX, USA

Online transmission in vivo dosimetry can help verify treatment delivery in
new and exciting ways, including monitoring the progression of treatment.
However, it does not offer the same information as pre-treatment QA, anddoes not serve as a complete replacement. Rather, online transmission invivo dosimetry is a complement to the pre-treatment QA that is necessary
to achieve robust and logical treatment verification. Pre-treatment QA does
not test as many treatment aspects as in vivo transmission dosimetry, but it
does check known sources of possible delivery error, and it does so before
the patient is exposed to radiation.
Pre-treatment QA is well established at detecting dose calculation errors andmachine-based dose delivery errors. Even though these errors may be detected with in vivo dosimetry, it is irresponsible if not unsafe to test for theseerrors while delivering the treatment to the patient. In such a case, where the
QA of the treatment is based entirely on in vivo measurements, a detected error is much more serious than if it is detected in a pre-treatment environment.
While a pre-treatment environment offers the physicist ample opportunity to
explore the error and revise the plan if necessary, the situation can not be
considered acceptable if an error is found during delivery of the treatment.
A best case scenario would be a simple interruption of the first fraction of
the treatment, with the patient asked to return a few days later with shaken
confidence in the procedure. Worse would be a negative dosimetric outcome
resulting from the partial delivery of an erroneous treatment.
While catching a dosimetric error at some point during the patient’s first fraction may be clinically insignificant for standard fractionation, this is not necessarily the case for hypofractionated or stereotactic therapies. With a limited
number of fractions, serious outcome consequences may result from the delivery of even part of a single fraction as there are few additional fractions inwhich to absorb this error. As these modalities become more popular, theneed for pre-treatment QA increases, rather than decreases.
A similar complication that can be avoided with pre-treatment QA is machine
clearance failure. Although good dosimetry practices can minimize the riskof potential collisions between the gantry and the couch or patient, clinical

T HURSDAY, M AY 12, 2011
experience shows that such treatment plans are nevertheless occasionallyapproved. Although there would not be a dosimetric complication from suchan error, it would still require an interruption of the treatment. It seems difficult to justify such an interruption because a clearance issue was missed asa result of pre-treatment QA being deemed unnecessary and obsolete.
In addition to the above needs for pre-treatment QA, we must also consider
some of the limitations of online transmission in vivo dosimetry. First, numerous substantial correction factors go into EPID-based transmission dosimetry,addressing its very sensitive energy dependence and ghosting artifacts. Although methods exist to correct for these effects, this remains a less robust
dosimetric technique than ion chamber readings that have minimal, well established, and well understood correction factors. Second, for this dosimetry
approach to be "online," results are largely limited to planar fluence or dose.
Although 3D back-calculations onto the patient are possible, it is not feasible
to do this with an accurate algorithm quickly enough as to allow intervention
in that fraction. Planar dose information is a useful tool for gross error checks,
but it has been shown to be insensitive to clinically relevant dosimetric errors.
This further complicates the idea of relying solely on online in vivo dosimetry,as this technique may not be a viable tool for treatment plan assessment.
Simply, while in vivo dosimetry offers new QA options that are not available
with pre-treatment techniques, reasonable clinical practice must continue toevaluate the treatment plan before the patient is exposed to the beam.

D EBATES 237

P OSTERSB REAST C ANCERISIORT Meeting

S 241

Breast Cancer
585 poster>10 YEARS FOLLOW UP AFTER IORT IN EARLY BREAST CANCER:
CLINICAL AND RADIOLOGICAL OBSERVATIONS
S. Usychkin1 , F. Calvo2 , M. Santos3 , J. L. Tisaire Sanchez1 , C. Bourgier4 ,R. Beni5 , H. Marsiglia1
G RUPO IMO, Radiation Oncology Department, Madrid, Spain
2
H OSPITAL G REGORIO M ARAÑÓN, Department of Oncology, Madrid, Spain
3
H OSPITAL C LINICAL B ENIDORM, Department of Radiation Oncology,
Benidorm, Spain
4
I NSTITUT G USTAVE R OUSSY, Radiation Oncology Department, Villejuif,
France5
H OSPITAL S AN F RANCISCO DE A SIS, Department of Surgery, Madrid,
Spain

1

Purpose: To describe long-term outcome findings after intraoperative electron boost at the time of tumorectomy and external radiotherapy for breast
conservation in early stage breast cancer patients (p).
Materials: From 1997 to 2000, 13 patients were treated in a breast conserving program including IORT component. IORT parameters were: dose
ranged from 800 to 1200 cGy; applicator size 5 cm (7 p), 6 cm (5 p), 7 cm
(1 p) diameter; electron energy 4 MeV (8 p), 6 MeV ( 2 p), 8 MeV (1 p), 10
MeV (1 p). Whole breast external beam irradiation dose was 50 Gy. External
electron irradiation tumorectomy boost (10 Gy) was added in 8 patients. Adjuvant chemotherapy was administered to 7 patients and hormonal therapy to
9 patients.
Results: Age ranged from 35 to 69 years old. Tumor stages were: I (2 p),
IIA (9 p) IIB (1 p). With a median follow-up time of 12 years, 10 patients arealive with no evidence of disease (NED) (ranging from 8 to 13 years). Twopatients have died from progressive uncontrolled breast cancer. One local
relapse was documented. One patient was lost of follow-up at 4 years while
NED. Long-term cosmetic results were considered by responsible physician
within excellent / good categories. Breast fibrosis was reported in 5 patientsby mammography or ultrasound. Specific imaging changes within the IORT
boosted area are under investigations by prospective mammography, MRI
and PET-CT scan at maximal follow-up.
Conclusions: IORT boost contribute to long-term breast cancer control inearly stages patients. Updated results will be presented regarding breast
normal tissue late effects with more than a decade of follow-up.
586 poster
EARLY CLINICAL RESULTS OF OUR INTRAOPERATIVE BREAST
TREATMENT SERIES
C. Philippson1 , S. Simon2 , C. vandekerkhove2 , J. M. Nogaret3 , D. hertens3 ,I. Veys3 , D. Noterman3 , F. De Neubourg3 , D. larsimont4 , P. Van Houtte1
I NSTITUT B ORDET, Department of Radiation Oncology, Brussels, Belgium
2
I NSTITUT B ORDET, Department of Medical Physics in Radiation Oncology,
Brussels, Belgium
3
I NSTITUT B ORDET, Department of Surgical Oncology, Brussels, Belgium
4
I NSTITUT B ORDET, Department of Pathology Oncology, Brussels, Belgium
1

Purpose: After breast conservative surgery, the highest incidence of local
relapse (more than 85% of cases) occurred in the tumor bed (true recurrences). The remaining 15% of the relapses occurred in other quadrants
must be considered as new primary carcinomas. Intraoperative radiotherapy with electrons delivers a single dose of radiation equivalent to the total
dosage with external fractionated radiotherapy directly to the involved portionof the breast using a mobile linear accelerator located in the operating room.
Alternatively, a smaller dose can be delivered as an anticipated boost before
external radiation therapy.This paper will review our early experience.
Materials: From February to December 2010, 113 patients were selected forPartial Breast Irradiation. Thirty were excluded after preoperative MRI or during the intervention due to the tumor size, an involved sentinel lymph nodeor a non appropriated histology.Eighty-three patients (mean age 61, range
40-84) were evaluable; two of them had bilateral tumors. Sixty-seven tumor
beds were treated with 21 Gy prescribed at the 90% isodose as a complete
radiation treatment. In all those cases, the tumor size was then smaller than 2
cm and the sentinel node was not involved. Eighteen patients received 9 Gy
as a boost prescribed at the 90% isodose. The boost approach was chosen
due to the involved sentinel lymph node, the size larger than 2 cm or a lobular histology. These patients received postoperative external radiation.The
mobile linear accelerator delivers electrons at different energies: 4, 6, 9 & 12
MeV. The alignment of the beam is achieved by a soft docking system. The
flat and bevelled (15◦ & 30%) used applicators have a diameter ranging from35 to 65 mm. The treated depths vary between 10 and 37 mm. These treateddepths could be modulated by the use of boluses.
Results: The operative time was slightly increased. No immediate surgical morbidity was noticed. Late local side effects include hematoma (1.2%),
breast infection (1.2%), axillary infection (1.2%), erythema (1.2%) and scardehiscence (1.2%). The cosmetic results were good or very good in 87.5%.

S 242

GI AND P ELVIC T UMORSB REAST C ANCER

Conclusions: This technique is not associated with any operative difficulties. We need to access long term results according to local relapse risk andcosmesis.
587 poster
FMECA ANALYSIS OF THE IORT PROCESS FOR BREAST CANCER
G. Frezza1 , R. Romagnoli2 , F. Mosconi1 , I. Zaccherini2 , A. Baldissera1 , C.
Degli Esposti1 , R. Bisognin3 , D. Moretto4 , M. C. Cucchi5 , L. Lanzoni5 , R.
Velardi5
1
O SPEDALE B ELLARIA, Department of Radiotherapy, Bologna, Italy
2
O SPEDALE B ELLARIA, Department of Medical Physics, Bologna, Italy
3
O SPEDALE B ELLARIA, Department of Oncology, Bologna, Italy
4
O SPEDALE B ELLARIA, Quality Assurance Division, Bologna, Italy
5
O SPEDALE B ELLARIA, Surgical Oncology, Bologna, Italy
Purpose: Failure Mode Effects and Criticality Analysis (FMECA) is a tool forprospectively evaluating safety and reliability of a process. We report ourexperience in applying FMECA in the setting of IORT procedure for breast
cancerMaterials: We performed a FMECA analysis for IORT process for breast cancer. We faced the following tasks: (1) Definition the work group, (2) Complete
and detailed analysis of the process (flow chart and responsibility map), (3)Identification of possible failure modes, consequences and causes; (4) Quantitative analysis, by assigning Risk Probability Numbers (RPN).These werebased on tabulated scores for the severity, frequency of occurrence, and detectability, each on a scale of 1 to 10; and (5) Search of improvements thatare both feasible and effective.
Results: We analyzed 46 different activities, parts of the whole process,obtaining one or more failure modes for each.For every failure mode, RPN(Risk Probability Numbers) were established, defined as:RPN= Severity X
Frequency of Occurrence X Detectability, each on a scale of 1 to 10. RPN
scores ranging from 8 to 540 were obtained.The six top-ranked failure modes(see table 1) were considered for process improvements.

Conclusions: The multi-professional aspect is a peculiarity of IORT process,as Surgeons, Nurses, Radiotherapists, RTTs, Medical Physicists, Anaesthetist and Pathologists work very closely. Indeed, our FMECA analysis
detected as minimum an activity for every professional, in the top six failure modes. We experienced FMECA as an excellent "team building" instrument, as all the involved professionals tackle each other and reach together
a deeper knowledge of the whole processAs well, IORT is a very high risk
process, as it adds up all the risks of a surgical procedure and those ofradiotherapy. FMECA technique provides a systematic method for finding
vulnerabilities in a process before they result in an error. We now intend toincorporate the specific improvement we designed, into our daily practice andreview the results of the whole process after their implementation.
588 poster
IN VIVO DOSIMETRY WITH DIODE AND SETUP VERIFICATION
THROUGH GAF CHROMIC RTQA IN IORT FOR BREAST IRRADIATION
B. G. Augelli1 , E. Roberto1 , F. Fusconi2 , P. Piatti2 , E. Fasci2 , F.
Checcaglini2 3 , E. Bracarda2 , M. Paolucci4 , R. Di Lorenzo4 , G. Lolli5 , M.
Patiti5
1
A.S.L. N.3 UMBRIA, U.O. Radioterapia Oncologica - Servizio Fisica
Sanitaria , Spoleto (PG), Italy
2
A.S.L. N.3 UMBRIA, U.O. Radioterapia Oncologica, Spoleto (PG), Italy3
ASL 1 UMBRIA, U.O. Radioterapia Oncologica, Città di Castello, Italy
4
ASL N3 UMBRIA, SS Fisica Sanitaria, Foligno (PG), Italy
5
ASL N3 UMBRIA, UO Chirurgia, Foligno (PG), Italy
Purpose: In the A.S.L. N.3 Umbria from March 2009 to December 2010 105
patients with different diseases (breast, stomach, pancreas and rectum) havebeen treated by IORT. In the breast cancer IORT treatment, the organ withhigher risk is the lung so we have estimated the dose to the lung by in vivo

dosimetry (IVD) using diodes and the alignment of the Disk Protection withapplicator by GAF Chromic RTQA.
Materials: The treatment of patients with breast cancer has been performed
giving a single dose of 10 Gy (boost treatment) or 21 Gy (exclusive treatment). We use a LIAC by Sordina with electron beams of 6,8,10 and 12
MeV, applicator with a diameter from 3 cm to 10 cm and shielding protection disk made of steel - PTFE (3+3 mm). The IDV systems diodes-basedis interfaced with electrometer in wireless mode. We have characterized thediode checking, at reference condition, the repeatability, reproducibility, linearity; we have determined the calibration factor using RW3 phantom by intercomparison with Roos or Markus chamber for different energy of clinicaluse (6, 8 and 10 MeV). The correction factor of the clinical field (from 8 cm
to 3 cm) have been determined in the following geometry: 20 cm of phantom+diode/chamber+shielding protection disk+different thickness of phantom(from 5 mm to 20 mm with step of 1 mm) that reproduce the mammary
gland+beam radiation. The verification of the alignment of the applicator withprotection disk have been performed with GAF Chromic RTQA. The surgeon
places the film and then the diode under protection disk. Finally, he reconstructs the mammary gland.
Results: The errors in diode calibration is 3.7 % for all energies. We haveanalyzed the data of 10 patients treated with 10 Gy (energy beam 6 MeV)
and 2 patients treated with 21 Gy (energy beam 8 MeV). The results obtained
from IDV diodes-based compared with experimental measurements allow toevaluate an error of the 13 %. However the average dose to the lung fortreatment boost is less than 30 mGy and for exclusive treatment is less than
85 mGy. Measurements performed with GAF Chromic films for checking thealignment disk - applicator showed an average setup error equal to 0,9 cm(max 1,9 cm and min 0.2 cm). The unshielded radiation due to misalignment
always occurs towards the medial side of the patient.
Conclusions: The dose delivered to the chest wall, measured by diode, allows to estimate a dose to the lung less than 1 % of the prescribed one. As
for the error setup, it is possible to suggeste to enlarge the margin required
for entry into the cavity of a disk 2 cm in diameter greater than the diameterof the applicator. Analysis of the results suggest to pay close attention to the
movements of the bed and the coupling between the applicator at the distaland proximal portion of it. The diode will also be used to measure the doseout of the mammary gland (upper the disk protection) and to evaluate the lungdose to the clinical use of other energies for two modes of prescription dose(boost and exclusive).

589 poster
INTRAOPERATIVE RADIOTHERAPY (IOERT) WITH ELECTRONS IN
BREAST CANCER.
A. Bouché1 , V. Morillo1 , F. Carlos1 , C. Casillas2 , E. BOLDO3 , A. Santos4
1
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofRadiation Oncology, Castelló de la Plana, Spain
2
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofRadiology, Castelló de la Plana, Spain
3
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofSurgical Oncology, Castelló de la Plana, Spain
4
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofMedical Physics and Radiation Safety, Castelló de la Plana, Spain
Purpose: The IOERT is a variety of treatment that consists of direct andprecise irradiation of a tumor or tumor bed during the surgical act, in a single
session. This allows direct visualization of target volumes, with the consistent
reduction of toxicity in adjacent healthy tissues through their separation. The
major recurrences in breast cancer can be found in the immediate vicinity ofthe tumor bed (85% in the same quadrant).The Purpose of this study was theevaluation of surgical complications, acute and aesthetic toxicity, in patientswith breast cancer and IOERT.
Materials: Between July 2008 and December 2010,12 women previously diagnosed with breast cancer were treated with conservative surgery. Meanage 67 (43-82). Inclusion criteria: PS 0-1, age ≥ 45 years, histology of infiltrating single centered ductal carcinoma G1-G2-G3; tumor size ≤ 2.5 cm,
no surgical macroscopically negative margins and study prior to surgery withmammography and magnetic resonance. IOERT as a boost was administered in 4 patients (33.3%), dose of 9 Gy, and as exclusive treatment in 8
(66.7%), dose of 21 Gy, including the PTV + 2 cm margin. The most usedapplicator was 7 cm (33.3%) and energy of 9 MeV (66.7%. External radiotherapy consisted of 50 Gy total dose, fractionation of 200 cGy/day. Acutetoxicity was assessed with the RTOG scale.
Results: The Mean follow-up was 29 months. One patient developed postopera-tive seroma requiring drainage in 2 cases. The acute toxicity was G1
in 7 (58.3%) and G2 in 5 (41.7%). The aesthetics was good or excellent in
75% and 25% acceptable.
Conclusions: The IOERT is administered in a single session and can beused as exclusive treatment in a selected group of patients, or prior to external beam radiotherapy as an overlay. Eliminates the possible vaguenessof the tumor location, allowing treatment with a limited volume of glandular
tissue. By preserving the skin and subcutaneous tissue of radiation reduces
the likelihood of fibrosis and telangiectasia, which improves aesthetics andtoxicity is similar to conventional treatments. It also reduces the duration ofradiation contributing to patients comfort and cost reduction.
590 poster
QUALITY OF LIFE AFTER INTRAOPERATIVE RADIOTHERAPY(IORT) AS A BOOST IN PATIENTS WITH EARLY BREAST CANCER
E. Blank1 , G. Welzel1 , U. Kraus-Tiefenbacher1 , M. Sütterlin2 , F. Wenz1
1
U NIVERSITY M EDICAL C ENTER M ANNHEIM, Clinic for Radiotherapy andRadiation Oncology, Mannheim, Germany
2
U NIVERSITY M EDICAL C ENTER M ANNHEIM, Department of Gynaecology
and Obstetrics, Mannheim, Germany
Purpose: Intraoperative radiotherapy (IORT) as a boost during breast conserving surgery is increasingly used. In a retrospective cross-sectional analysis, we assessed Quality of Life (QoL) and late toxicity in women treated with
an IORT boost followed by whole breast irradiation (WBRT).
Materials: Between 02/2002-12/2006, 142 patients (median age 63 years)
were treated with an IORT boost (20 Gy; INTRABEAM System) and WBRT
(46 50 Gy) after completed wound healing or chemotherapy. After a medianinterval of 34 months at the end of EBRT, QoL data were assessed in 103
patients with two reliable and valid questionnaires: the QLQ-C30 and QLQBR23. We also performed clinical examinations every 6 12 months anddocumented late effects according to the LENT SOMA scale.
Results: With a median follow-up of 32 months most toxicity and QoL scores
were good/excellent and QoL had no clinically relevant difference of > 10
points compared to an age adjusted population. However, our patients had
significantly lower ratings in global health/QoL (58.66 vs. 64.77; p = 0.016).
Patients with higher grade toxicities rated significantly more emesis/nausea(p = 0.018), constipation (p = 0.002), breast (p = 0.008) and arm symptoms(p = 0.013) and showed worse QoL (56.74 vs. 60.58 points). Pain > ◦ II had
most influence. Satisfied patients (89%) had fewer breast and arm symptoms(p < 0.001) and fewer higher grade toxicities (p = 0.004).

S 243

Conclusions: Patients with an IORT boost had a good QoL in a medianfollow-up of nearly three years. Higher grade toxicity had a small impact on
QoL.
591 poster
SURGICAL TIPS TO OPTIMICE BREAST IORT
E. BOLDO1 , R. LOZOYA1 , G. PEREZ DE LUCIA1 , A. Bouché2 , V. Morillo2 ,F. Carlos2
1
H OSPITAL P ROVINCIAL DE C ASTELLON, Surgical Oncology, CASTELLON,
Spain
2
H OSPITAL P ROVINCIAL DE C ASTELLON, Radiation Oncology, CASTELLON,
Spain
Purpose: Breast intraoperative radiotherapy (IORT) has been developed toreduce local recurrence rate, aesthetic radiation side effects and radiation
schedule. Nevertheless, all these objectives can be hampered if improper
surgical and radiation techniques are used. The aim of this report is to underline the surgical tips that, in our experience, must be fulfilled systematically toobtain the best results with breast IORT.
Materials: In our practice, surgical principles in breast IORT include: resection of the tumor before radiation, metilene blue marking of the resection
margins (figure 1), protection of the chest structures using aluminium roundprotectors (figure 2), purse string suture of the resection margins in order toinclude the risk area in the radiation field (figure 3), checking this inclusion(facilitated by metilene blue markings) after fixing the bolus (figure 4), using
as wider applicators as possible and protecting skin wedges with moistenedswabs (figure 5).
Results: From November 2008 to November 2010, 12 breast IORTs had
been performed in our center. The local recurrence rate has been 0% after a mean follow up of 29 (1-24) months. Aesthetic radiation side effects
have been mild, as none of our patients have been referred to plastic surgery.
Radiation schedule (compared to ERT) has been reduced in all cases.
Conclusions: Metilene blue marking of the resection margins altogether withmeticulous surgical and radiation techniques may help to achive breast IORT
advantages.

GI and Pelvic Tumors
592 poster
FEASIBILITY STUDY OF INTRA-OPERATIVE RADIOTHERAPY FOR
LOCALLY ADVANCED ESOPHAGEAL CANCER: PRELIMINARY DATA
L. Turri1 , M. Krengli2 , S. Gentilli3 , E. Negri4 , S. Torrente5 , E. Mones6 , L.
Masini5 , G. Gambaro5 , M. Garavoglia7
1
R ADIOTHERAPY U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ,Novara, Italy
2
U NIVERSITY OF P IEMONTE O RIENTALE, Novara, Italy
3
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ N OVARA, Novara, Italy
4
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ N OVARA, Oncology,
Novara, Italy
5
R ADIOTHERAPY U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ,Radiotherapy, Novara, Italy
6
R ADIOTHERAPY U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ,Radiation Physics, Novara, Italy
7
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Surgery, Novara, Italy
Purpose: To analyze the feasibility of intra-operative radiotherapy (IORT) in
patients affected by locally advanced esophageal cancer and candidates forsurgery
Materials: Eleven patients, 9 males and 2 females, aged from 52 to 72 years(mean 61.5, median 60) with locally advanced esophageal cancer were enrolled in this prospective study. Tumour locations were: 1 in upper, 7 in middle
and 3 in lower third. All cases were squamous cell carcinoma. Clinical TNM
stage was as follows: 5 T3N0M0, 4 T3N1M0, and 2 T3N0M1. The 2 cases
classified as M1 had sub-diaphragmatic lymph nodes enlarged at CT andpositive at PET. After multidisciplinary discussion, all patients were included
in an institutional protocol and candidate to pre-operative chemo-radiation
followed by surgery with IORT as a boost. Pre-operative radiotherapy wasprescribed with 3D-conformal technique using a treatment plan based on CT
and PET fused imaging to a total dose of 44 Gy in 22 fractions (2 Gy/fraction).
Two cycles of chemotherapy with cisplatin and 5-fluorouracil were given concomitantly to radiotherapy.
Results: Chemo-radiotherapy was administered in all but one patient who
received radiotherapy alone because of severe renal failure. Two patientsdeveloped chemo-related hematologic (G4) and renal/hepatic toxicity (G1).
Surgery consisted of total esophagectomy with standard mediastinal lymphadenectomy and neck esogastric anastomosis. IORT was delivered by a
dedicated linear accelerator after tumour removal to the operative tumour bed
and/or regional lymph nodal areas. Collimator with diameter of 4-5.5 cm andS 244IORT T ECHNOLOGIES , P HYSICS AND B IOLOGYIORT T ECHNOLOGIES , P HYSICS AND B IOLOGY

beveled angle from 0◦ to 30◦ were used with electrons of 6-12 MeV to deliver
a total dose of 10-15 Gy (median 12 Gy). Pathological stage was as follows:
1 pT2N0M0, 3 pT3N0M0, 5 pT3N1M0, 2 pT3N0M1; 9/10 were R0, 1 R1, and
1 R2. Postoperative complications occurred in 3/11 cases and consisted of
pulmonary embolism, gastro-tracheal fistula, and respiratory distress. Posttreatment follow-up ranged from 2 to 31 months (median 14 months). Threeout of 11 patients are still alive with no tumour progression, 4/11 are alivewith disease progression and 4/11 died, 3 of tumour progression and 1 of
pulmonary embolism. Of the 7 patients with tumour progression, 1 developed
regional, 2 regional and distant, and 4 distant relapse.
Conclusions: IORT during surgery for esophageal carcinoma is a feasible
procedure and can be combined with preoperative external beam radiotherapy and chemotherapy to the tumour bed. A larger number of patient andlonger follow-up is needed to assess long-term outcome including late side
effects, local control and relapse-free and overall survival.
593 poster
INTRA-OPERATIVE RADIOTHERAPY WITH ELECTRONS AND
SURGERY IN PELVIC RECURRENCE
V. Morillo1 , A. Bouché1 , F. Carlos1 , J. López2 , R. LOZOYA3 , J. C. Ruiz
Rodriguez2
1
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofRadiation Oncology, Castelló de la Plana, Spain
2
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofMedical Physics in Radiation Oncology, Castelló de la Plana, Spain
3
H OSPITAL P ROVINCIAL DE C ASTELLON, Department of Surgical Oncology,
CASTELLON, Spain
Purpose: The percentage of local relapse after radical treatment in rectal
neoplasias is around 25%. Fifteen percent die without distant disease andmedian survival without treatment is around 8 months.The purpose was theassessment of recurrence treated with surgery plus IOERT in our institution,in terms of locorregional control and toxicity.
Materials: Retrospective study from March 2008 to December 2010 of sevenpatients with rectal recurrence. They have received IOERT as part of the rescue treatment. 57.1% were women and 42.9% men. The median age was 63
years (range 45-82 years). The medium interval since the primary tumor isdiagnosed onto the recurrence was 20.7 months. 71.4 % were asymptomaticto the recurrence. Five of the seven patients examined received neoadyuvant
radiotherapy (range 45-54 Gy) and the other two adyuvant radiotherapy.The
treatment volume was defined by tumor size plus a margin that contains thearea at risk; marked with surgical clips for a correct display. The energy ofelectrons being used 9-15 MeV. The IOERT dose varies according to the surgical margin: R0, R1, and R2 with 10, 12.5-15 and 17.5-20 Gy, respectively(90% isodose). Assessment of toxicity according to RTOG scale.
Results: With a median follow-up of 32 months, the current overall survivalof 57.1% is not statistically significant (p= 0.661) vs R0 vs R1. The diseasefree survival, distant and the local control is about 57.1 %, 71.4% and 85.7%,
respectively. The dominant pattern of distant relapse: liver and lung.As for
maximum acute toxicity was: grade II rectal 28.6%, moderate neuropathic
pain 28.6% and genitourinary in 42.9 %. There were no late toxicity.
Conclusions: The use of IOERT in treatment of recurrent rectal can significantly improve local control without increasing the incidence and severity of
toxicity. Individualized strategies and longer follow-up are needed.

> 60 years, pT 2.5 cm and pN0, ductal invasive unifocal carcinoma, andtumor-free margin of >10 mm. In the other 226 patients the IORT was used
as tumor bed boost with dose of 10 Gy, followed by 44-50 Gy whole-breast
external-beam radiotherapy, in 16-25 fractions respectively. in vivo dosimetry has been carried out both by radiocromic films and diodes. We treated
17 patients with gastric cancer, not submitted to neoadjuvant treatment, 25
patient with locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy 17 tumors of the pancreas treated in 10 cases with palliative
intent and 7 cases with curative intent, the doses used were ranged from 10
to 20 Gy.We also conducted 11 patients with soft tissue sarcoma, 22 patientswith prostate cancer with a dose of 18 or 20 Gy.
Results: We evaluated 175 breast cancer with a follow-up of at least than 12
months: 131 treated with IORT as anticipated boost and 44 were treated withIORT alone. For the 131 cancer treated with boost the median follow-up was
35 months. We observed a local recurrence and lymph node recurrence andone patient developed metastases. For 44 patients treated with IORT alone,
the median follow-up was 33 months To date there has been only one local
recurrence outside the quadrant of the primary tumor. There have been noserious surgical or radiation complications. After follow-up of at least than 12
months, no patients with prostate cancer and rectal cancer developed a local
relapse. No other long-term complications occurred.
Conclusions: Our experience with IORT with movable linac suggests that
this technique is feasible, user friendly, and might be an appropriate treatment
for selected patients. IORT the accurate localization tumor bed, minimizes
the damage to the normal tissue. Results in terms of local control are very
encouraging, but need to be confirmed by longer follow-up.
595 poster
COMPARISON OF DIFFERENT METHODS FOR OUTPUT FACTOR
MEASUREMENTS ON 10 MEV LIAC LINACS
R. Romagnoli1 , S. Magi1 , M. Palombarini1 , G. Felici2
1
2

AUSL DI B OLOGNA , O SPEDALE B ELLARIA, Fisica Sanitaria, Bologna, Italy
S ORDINA S. P.A., Saonara (PD), Italy

Purpose: We evaluated on three different 10 MeV LIAC LINACs the dosimetric characteristics of different detectors available for Output Factors measurements.
Materials: Several dosimeters were used to measure Output Factors (OFs)on 10 MeV LIAC LINACs.In particular, on one LIAC (S/N 0011), measurements were performed by: PTW Pin Point Chamber; PTW Advanced Markus
Chamber, PTW Roos chamber and EBT 2 Gafchromich films. PTW Rooschamber was not used for measuring 4 cm diameter applicator, because thedimensions of the detector are comparable with the applicator’s ones.For 60
mm applicator, measurements were performed using Fricke dosimeters as
well.Fricke dosimeters were made and read after their irradiation by ENEA
INMRI, the National Institute of Ionizing Radiation Metrology, Italian PrimaryStandard Institute.Furthermore, on three different 10 MeV LIAC LINACs (oneinstalled in Bologna, Bellaria Hospital and two in Rome; Sordina S.p.A.) Advanced Markus measurements were performed to compare OFs.
Results: For all applicators wider than 4 cm, all measurements performed
with different methods are in good agreement (CV% = 0- 2%) for all energies, while OFs measured for 4 cm applicator show a greater variability (CV= 2-4%), even if Roos chamber was excluded a priori in such evaluation,
because of its dimensions. Measurements performed on different 10 MeV
LIAC LINACs using Advanced Markus chamber show OFs in good agreement (CV% 0-2%).

IORT Technologies, Physics andBiology594 poster
ANALYSIS OF ACTIVITY OF INTRAOPERATIVE RADIOTHERAPY OF
TWO HOSPITALS IN UMBRIA (CITTÀ DI CASTELLO AND FOLIGNOITALY ) HOSPITALS UNDER THE SAME MANAGEMENT.
F. Checcaglini1 , A. Marina1 , A. Massimo1 , E. Bracarda2 , C. Francesca1 , F.
Francesca1 , F. Fabrizio2 , P. Paolo2 , A. Boris2 , P. Massimiliano2 , P. Andrea1 ,R. Giampaolo1
1
ASL 1 UMBRIA, Department of Oncology, Città di Castello, Italy
2
ASL N3 UMBRIA, Department of Oncology, Foligno (PG), Italy
Purpose: We report data on 435 patients treated in Radiotherapy department
in Citt Castello and Foligno Hospitals directed by Dr. Checcaglini Franco.
From February 2005 at the Citt Castello Hospital and from January 2009 at
the Foligno Hospital is made intraoperative radiotherapy with a movable linac
NOVAC 7 (electron energies from 3 to 9 MeV) in Citt Castello and with LIAC
(electron energies from 3 to 12 MeV) in Foligno.
Materials: We performed a total of 438 IORT of these 343 breast cancer,
107 patients were treated with IORT exclusively with one 21 Gy fraction prescribed at 90% isodose. These showed the following characteristics: age

Conclusions: For applicator’s diameter larger than 4 cm, OF measurements can be equally performed by the different dosimetric methods here
investigated (plane parallel chambers, small thimble chamber, gafchromich
films, Fricke dosimeters), while for smaller applicators, different detectors givelarger variations in OF measurements, highlightning the need of further investigations. The same method (Advanced Markus measurements) applied on
different 10 MeV LIACs, gives coherent results, showing uniformity in construction method.

596 poster
DEVELOPMENT AND OPTIMIZATION OF A BEAM SHAPER DEVICEFOR A MOBILE IORT ACCELERATOR
A. Soriani1 , G. Felici2 , A. Ciccotelli2 , G. Iaccarino1 , M. D’Andrea1 , L.
Bellesi1 , P. Pinnaro3 , C. Giordano3 , L. Strigari1
1
I STITUTO R EGINA E LENA - IFO, Medical Physics Lab, Roma, Italy
2
S ORDINA S. P.A., Saonara (PD), Italy
3
I STITUTO R EGINA E LENA - IFO, Radiation Oncology Department, Roma,
Italy
Purpose: The IORT technique usually allows to place outside the field thenormal tissues not to be irradiated, but for some structures or in some special
cases, this is not possible. For example in sarcomas targets have usuallyirregularly elongated shapes, with adjacent anatomical structures that haveto be preserved. The aim of this study was to design build and characterize aprototype of a dedicated IOERT beam shaper that conforms the beam to thetarget geometry.
Materials: The first step was the choice of materials that absorb theelectron beam without producing other undesirable effects, such as X-ray
bremsstrahlung radiation. We selected a combination of a first layer of low
Z material, PTFE, with a second layer of high Z material, Steel (AISI 316 LN),
undertaking sterizability and biocompatibility of the device. To define the optimal thicknesses we used Monte Carlo simulations with the code BEAMnrc of
a 12 MeV electron beam produced by a mobile IORT LIACTM . The multileaf
system consists of four mobile graduated bi-component blades, which allows
to obtain any rectangular fields. We used diode in water phantom to determine the effect on the PDDs varying the field size and the air gap between
the device and the phantom surface. Gafchromic films were used in a PMMA
phantom to measure the isodoses of rectangular field. Finally measurementsof the output factors at the reference depth for all energies, at different air
gaps, varying the side of the rectangular field by a cylindrical micro chamber
were performed.
Results: The optimal blade thicknesses (from MC simulation) were equal to
29 mm of PTFE and 8 mm of steel. This choice ensures both a significant
attenuation of the X-rays produced and an adequate mechanical strength ofthe entire system. It’s possible to conform fields to any rectangle inscribable a circle 100 mm in diameter. The four blades are mounted on a special
device (support) and can slide on each other so that there are no areas oflower attenuation of the beam (see figure). The total length of the applicator device, with the shaper fixed at its end, is equal to 60 cm like a standard
LIAC Applicator.From our results we can observe that when the short side of
the rectangular field is reduced, the R50 value decreases and Rmax moves
towards phantom surface while the output factors first increase and then decrease at each energy. This effect becomes more evident when the air gap
increases.

S 245

Conclusions: The designed devices, optimized and tested in laboratory, areeffective for the protection of organs at risk within the field of radiation. Tests
on the field conforming system, confirm its validity when the IORT techniquerequires fields with shapes other than circular or elliptical.
597 poster
DOSE DISTRIBUTION OPTIMIZATION WITH NOVAC7 USING THE
PROTECTION DISC IN BREAST ELIOT: A MONTE CARLO – GEANT4
STUDY
G. Russo12 , C. Casarino3 , G. C. Candiano3 , G. Arnetta3 , P. Spiccia3 , G.
Borasi3 , C. Messa145 , M. C. Gilardi15
1
CNR-IBFM, Cefalù (PA), Italy
2
F ONDAZIONE I STITUTO S AN R AFFAELE G. G IGLIO DI C EFALÙ, Cefalù (PA),Italy
3
L ABORATORIO DI T ECNOLOGIE O NCOLOGICHE HSR G IGLIO, Cefalù (PA),Italy
4
U NIVERSITY OF M ILANO -B ICOCCA, Milano, Italy
5
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Milan, Italy
Purpose: Improvement of the protection disc performance in intra-operative
breast electron radiation treatment investigating new disc characteristics (materials and thicknesses).
Materials: The Geant4 Monte Carlo toolkit was used to simulate the entire
geometry of linear accelerator NOVAC7 (accelerator head, monitor chambers, collimators system); the characteristics of the electron beam (energy,
spatial and momenta distributions); the setup of the breast treatment (water
phantom for the patient and the protection disc) and to calculate the dose distribution inside water phantom positioning the disc at the depth corresponding
to 90 percent of the max dose released (R90). Aim of this work is to reduce
the thickness of disc and improve the comfortable clinical setup. The following disc configurations were simulated, double-layered PMMA-W (tungsten),
Al-W, Cu-W and triple-layered PMMA-Cu-W, and analyzed to calculate theRadiation Attenuation (RA) and the Back-Scattering Factor (BSF). The best
disc configuration (maximum RA, minimum BSF and minimum thickness) was
studied at different beam energies and depth positions in treatment region(from 10 to 24 mm).
Results: Every configuration allows to reduce drastically the energy release outside the treatment area (97%<RA<98%). Nevertheless, most cases
present a un-trivial back-scattering over peak (3%<BSF<10%). Otherwise,
the use of the double layered Al-W (5.0 mm) and the triple layered PMMACu-W (4.0 mm) discs give a zero BSF in the treatment region resulting in a
uniformly well dose distribution. The last is the best configuration giving a reduction of the dose by more than 97% with a maximum dose over peak equal
to 7.0% with all available energies and at different depth positions.
Conclusions: The triple layer PMMA-Cu-W (4.0 mm) is the best configuration, combining a well suited protecting role with a comfortable clinical setup
due to the small-sized thickness. This disc may be a good alternative to thestandard Al-Pb (6.0 mm) actually used.
598 poster
IN VIVO DOSIMETRY IN IORT BREAST CANCER TREATMENT
F. Cavagnetto1 , S. Agostinelli1 , M. Guenzi2 , M. Gusinu1 , M. Zeverino1 , G.
Taccini1
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Department ofMedical Physics and Radiation Safety, Genova, Italy
2
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Departments ofRadiation Oncology and Cell Biology, Genova, Italy
Purpose: The aim of this work is to illustrate our experience in IORT breast
cancer treatment using MOSFET in vivo dosimetry: our activity started in
September 2009 with partial breast irradiation using an electron beam treatment unit; up to November 2010 we have treated 230 patients, for 43% cases
we have performed in vivo dosimetry
Materials: Treatments were performed by LIAC (Sordina) mobile Linear accelerator with 4, 6, 8, 10 MeV electron beams, using cylindrical applicatorswith different diameter between 4-10 cm; a steel-PTFE plate (4mm+3mm) is
place between the deep face of the residual breast and the pectoralis muscle
to minimize the thoracic wall irradiation. Since march 2010 we have started
to use MOSFET (Best Medical) detectors to determine exit dose, in order
to measure the dose collected by the deeper part of the target, the detectors are placed inside a thin and sterile catheter and fixed at the centre of
the PTFE side of the disk before the insertion in the breast, Monitor Units(MU) are splitted in two parts in order to perform two different measures toallow MU corrections. The detectors were calibrated with the 4 Linac electron
beams in the same geometry of daily dosimetry check; the errors in MOSFET
calibration are lower than 3% for all the energies1 . Prescribed doses ranging between 10 and 21 Gy at 95% or 90% isodose depending on tumor size,
target depth and tumor typology, it as been established to perform MU corrections if the differences between delivered and prescribed dose is higher than
5%, taking in account isodose normalization, if MOSFET reading are lower
than prescribed dose no correction because it can’t exclude a bad dosimeterS 246OTHER TOPICSIORT T ECHNOLOGIES , P HYSICS AND B IOLOGY

positioning.
Results: The istogram in Figure 1 shows the percentage deviation between
measured and prescribed dose corrected for depth and isodose normalizationin the first part of irradiation, 12% of MOSFET readings are higher than 10%.
To understand these abnormal readings we have tested different experimentally set up and we can exclude a MOSFET angular response dependence(differences lower than 6% in a range 0-180◦ ) and also an increase due tobackscatter radiation from attenuator plate in case of a thin tissue layer on
the plate (water phantom measurement with MOSFET and Gafchromic film
at different depth with and without attenuator plate under the dosimeter givedifferences lower than 5%). Only creating a set up with different tissue layer
and air interposed (using a glove semi-fill of water) and the applicator tilted
we have measured differences higher than 10%.

Conclusions: Next step will be to investigate the problem using Monte Carlosimulation with different set up, in order to support our experimental results. 1 F.Cavagnetto, S.Agostinelli, R.Corvo’, S.Garelli, M.Guenzi, M.Gusinu,
G.Taccini "In vivo dosimetry in IORT for breast irradiation: the preliminary experience of IST in Genoa" Abstract, 6th International Conference of ISIORT2010
599 poster
INITIAL CLINICAL EXPERIENCE OF PENCIL BEAM DOSE MODELLING FOR INTRAOPERATIVE ELECTRON RADIATION THERAPY(IOERT)J. A. Santos Miranda1 , J. Pascau2 3 , M. D. Lardies4 , M. Desco2 3 , F. Calvo1
1
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Oncología,
Madrid, Spain
2
H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Unidad deMedicina y Cirugía Experimental, Madrid, Spain
3
U NIVERSIDAD C ARLOS III DE M ADRID, Departamento de Ingeniería
Biomédica y Aeroespacial, Madrid, Spain
4
T ÉCNICAS R ADIOFÍSICAS , S.L., Zaragoza, Spain
Purpose: RADIANCE is an IOERT patient-specific treatment planning system for virtual surgical simulation and electron beam interaction description
with patient anatomy. The tool facilitates applicator positioning on a preoperative available CT, displaying Dose Volume Histograms (DVHs) calculated on pre-segmented regions of interest. An implementation of Pencil
Beam (PB) algorithm for dose modelling has been included in RADIANCE,
improving the simulator capabilities and turning the system into a real treatment planning tool. The purpose of this work is to present the initial results
when PB is used to calculate electron dose on a real patient.
Materials: The RADIANCE system and the PB implementation have beendeveloped by GMV (Madrid, Spain) and Ticas Radiofcas (Zaragoza, Spain)
in collaboration with three hospitals (Hospital General Unversitario Gregorio
Mara Clca La Luz and Hospital Provincial de Castell The PB algorithm calculates the dose distribution depending on the treatment parameters (applicator
dia meter, bevel and gantry angles and treatment energy) and the Hounsfield
Units from the CT. Geometrical or free-hand regions can be included, with
their corresponding electronic densities, in order to simulate bolus effect orprotections used during the radiation process, and the corresponding modifications of the treatment beam. Breast cancer was selected as the initialcase model, since it presents several remarkable features: partial breast irradiation is one of the main applications of IOERT, the anatomy is minimally
distorted during treatment compared to the previous CT scan and the area
includes several interfaces (air in lung, fat tissue in the breast and bone in theribs). It is expected that PB calculations will correctly identify beam interaction with those regions. Several planning options were tested modifying all
the described treatment parameters.
Results: Our results show that isodose curves modify as expected in all interfaces with air, fat tissue and bones. Dose distribution is more heterogeneous
when estimated using PB than when approximated form water measures,
particularly on the applicator edges. The useful treatment volume is slightly
smaller with PB, what is expected since electron interaction with the tissue
is being estimated. Evaluation of protections shows that they are effective
stopping the radiation. Bolus behaviour according to PB is consistent, giventhat dose in tumour bed surface is increased when radiation beam interacts
first with the bolus. For the kind of treatment that has been studied (breast),energies commonly used (≤ 6 MeV) do not deposit significant dose on lungand ribs.

dures using C-arm based 3D-imaging appear to be feasible and manageable in an acceptable time, resulting in a proof of principle for the proposed
method. For routine use, improvements are needed in image quality, beamarrangement and dose calculation.
601 poster
SHIELD PLACEMENT ASSESSMENT DURING INTRAOPERATIVERADIOTHERAPY BREAST TREATMENTS
S. Simon1 , C. Philippson2 , C. Vandekerhove1 , J. M. Nogaret3 , I. Veys3 , D.
Noterman3 , F. De Neubourg3 , P. Van Houtte2
1
I NSTITUT J. B ORDET, Department of Radiophysics, Brussels, Belgium
2
I NSTITUT J. B ORDET, Department of Radiation Oncology, Brussels,
Belgium
3
I NSTITUT J. B ORDET, Department of Surgery, Brussels, Belgium

Conclusions: PB dose modelling has identified several aspects of IO ERT
treatment that cannot be evaluated with conventional water phantom measures. RADIANCE IOERT simulation and planning system moves one step
forward to a more precise dose estimation by the inclusion of this algorithm.
The use of PB allows quantifying and predicting the influence of several parameters in this IOERT breast model. We expect to validate these results onother locations.Acknowledgements: the authors would like to thank GMV for
their leadership in the development of radiance. This project has been fundedby Spanish Ministry of Science and Innovation (PI09/90568, PSE-3000002009-5, IPT-300000-2010-3, Comunidad de Madrid ARTEMIS S2009/DPI1802 and FEDER founds).
600 poster
POSTPLANNING OF A THREE-DIMENSIONAL DOSE DISTRIBUTION FOR INTRAOPERATIVE ELECTRON RADIATION THERAPY(IOERT) USING INTRAOPERATIVE C-ARM BASED 3D-IMAGING : A
PHANTOM STUDY
F. Roeder1 2 , O. Schramm1 , A. Schwahofer3 , C. Timke2 , G. Habl1 , M.
Tanner4 , P. Huber1 2 , J. Debus1 2 , R. Krempien5 , F. Hensley1
1
U NIVERSITY OF H EIDELBERG, Department of Radiation Oncology,
Heidelberg, Germany
2
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Radiation
Oncology, Heidelberg, Germany
3
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Radiation
Physics, Heidelberg, Germany
4
U NIVERSITY OF H EIDELBERG, Department of Surgery, Heidelberg,
Germany
5
A KADEMISCHES LK DER U NIVERSITÄT C HARITÉ, Department of Radiation
Oncology, Berlin, Germany
Purpose: In contrast to other radiation techniques, currently no planning tool
for three-dimensional dose calculation is available for IORT procedures. We
therefore conducted this phantom study to evaluate the use of intraoperative
C-arm-based 3D-imaging to establish a post-planning method as first step
toward a three-dimensional planning tool.
Materials: We placed a metal-free imaging sleeve, which allows a direct insertion of a treatment applicator, on a phantom containing bone-equivalent
structures. The sleeve contains radioopaque markers to define applicator
position and beam axis. A mobile c-arm system with 3D-option was placed
over the arrangement. 3D-datasets of images were recorded with the c-arm
continuously moving around the arrangement. To simulate the postoperative
CT scan, a conventional CT-scan using the phantom without applicator wasused. The datasets were imported into a commercially available treatment
planning system and fused according to the bone-equivalent structures. An
electron beam was defined according to the radioopaque markers in the carm dataset. Then the dose distribution of the electron beam was calculatedon the conventional CT scan.
Results: Appropriate placement of the C-arm system and recording of theimages were easily manageable in acceptable time. The imaging sleeve, theradioopaque markers, the air-tissue surface and the phantom-inhomogenities
were sufficiently visible, although image quality was limited compared to conventional CT scans. Import via DICOM and fusion of the datasets according
to the bone-equivalent structures were easily manageable in acceptable time.
The arrangement of the electron beam according to applicator size and plane
as defined by the radioopaque markers was performed manually and needed
extensive time for stepwise adjustments, but was generally feasible. The calculated dose distribution was similar to known distributions of IORT procedures from phantom measurements, although for simplifications purposes,
the calculation of the dose distribution was done using beam characteristics
of a conventional accelerator.
Conclusions: In summary, all steps of the proposed post-planning method
for the calculation of a three-dimensional dose distribution of IORT proce-

Purpose: Partial Breast Irradiation with Intraoperative electron beams is associated with the delivery of a single high dose of radiation. In such circumstances, the selectivity principle must always be respected. In order toprevent unnecessary irradiation of the ribs or the lung, a shield with suitable
diameter, thickness and composition can be positioned on the pectoral muscle. The objective of this study is to assess the impact of different treatment
parameters on the correct alignment between the shield and the beam.
Materials: As soon as the pathological tumor size has been determined, afield diameter and a shield diameter are chosen in the OR. First, the shield issutured to the pectoral muscle, then the mammary gland to be treated is sutured above the shield and that makes the shield position difficult to assess.
Intraoperative electron treatment is performed with a mobile electron accelerator. The treatment parameters are the applicator diameters (available from
3 to 10 cm), the type of applicator tip flat or beveled-, the energies ranging
from 4 to 12 MeV, the uses or boluses (none, 5 mm or 10 mm) to modulate
the depth of the prescription isodose, the gantry and tilt angles to align theaccelerator with the applicator with a laser soft docking system. The alignment between the shield and the field is evaluated with a classical silver film,
placed on the beamstopper. The darkening of the film is due to the braking
radiation produced by the electron slowing down.
Results: 73 films from 72 patients have been processed. When the beam
is not perfectly aligned with the shield, a darker eclipse is visible inside theimage of the beam. The shield coverage is calculated as the part of the beam
surface covered by the shield. The general mean shield coverage is 85%(range: 40-100%). The shield alignment was considered as poor (<60%) in 5
cases (7%), as fair (between 60 and 80 %) in 12 cases (17%), as good (between 80 and 90 %) in 17 cases (23%) and as excellent (>90%) in 39 cases(53%).Nor the shield depth in tissue, nor the energy used, nor the type of
applicator tip, nor the use of boluses, nor beam orientation (to see any gravity
effect on the shield) seem to have an impact on the mean shield coverage.
On the other hand, the shield size does logically matter. We defined theshield margin as the shield diameter minus the beam diameter at the depthof the shield. When the margin is less than 10 mm, the mean shield coverageis 76% (range: 50-98%). When the margin is between 10 and 20 mm, themean shield coverage is 84% (range: 40-100%). When the margin is larger
than 20 mm, the mean shield coverage is 95% (range: 85-100%).
Conclusions: In Intraoperative Radiotherapy, a correct shield placement isof great importance to prevent side effects. The shield alignment with thebeam can be easily controlled by a plain X-ray film. Even when one takes
really care of the shield position, the shield coverage is not always optimum.
A margin larger than 10 mm and preferably, if the patient anatomy permits,larger than 20 mm is needed to obtain excellent coverages.

Other topics
602 poster
A POSITIONING TOOL FOR REPRODUCIBLE MEASUREMENTS OF
BEVELLED IORT APPLICATORS ON ACCELERATORS WITHOUT
ROOM-RELATED POSITION INDICATORS
A. Runz1 , K. Wagenknecht2 , E. Gernot1 , F. Roeder3 , C. Timke3 ,F. Hensley2
1
2
3

G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Heidelberg, Germany
U NIV. K LINIKUM H EIDELBERG, Heidelberg, Germany
U NIVERSITY OF H EIDELBERG, Heidelberg, Germany

Purpose: Applicators with bevelled end are a useful tool for many applications in Intraoperative Radiation Therapy (IORT) with electrons: " they may
be used to direct an electron field into a hollow structure in the patient’s bodywhich is not accessible in an orthonormal approach, " they may be used toplace an applicator onto the surface of a slanted surface without excessive rotation of the accelerator head" or they may simply be used to produce an enlarged, oval field with an applicator of smaller diameter.However, commissioning bevelled applicators can be problematic since it is difficult to reliably (andS 247

reproducibly!) adjust the beam angle and to centre a measuring probe within
the radiation field, especially on a mobile accelerator without fixed isocentre
and room-related positioning aids.
Materials: A positioning aid was developed to reproducibly place the bevelledapplicators of a mobile electron accelerator (Liac ) onto the surface of a remotely controlled motorized water phantom (MP3, PTW-Freiburg ). The tool isbased on the TRUFIX®detector positioning system (PTW-Freiburg) which isdesigned to provide an exact positioning of a large number of detectors. Thissystem uses a special setup tool with which the motor drive and the chamber carriage of the phantom are positioned in relation to the water surface.
The tool is then replaced by a set detector holders which put each detector’s
effective point of measurement onto exactly the same position. In our development, the positioning tool is again used to adjust the phantom drive tothe water surface. The tool is then replaced by a template which defines theexact vertical and horizontal position and the entrance angle of the bevelledapplicator. The template is mounted onto the motor drive of the phantom anddesigned to place the centre of the applicator at a defined distance from theposition indicated by the setup tool. After adjusting the accelerator and applicator, the motor drive coordinates are corrected for the distance between theapplicator centre and the measuring point. By this adjustment the detector isplaced at the water surface under the centre of the applicator so that the xand y-axes of the water phantom follow the axes of the oval given by the endof the applicator.
Results: Repeated measurements of the radiation fields from bevelled applicators provide reproducible dose distributions.
Conclusions: The positioning tool may be a useful device also for the commissioning of other applicators, other accelerators and other types of measurement.1 Sordina S.p.A. , Via Emilia Romagna, 9, Saonara (PD) Italy2
PTW Freiburg, Lrracher Str. 7, 79115 Freiburg, Germany
603 poster
INTRA-OPERATIVE RADIOTHERAPY WITH ELECTRONS (IOERT)AND SURGERY IN RECURRENCE AND PRIMARY TUMORS
F. Carlos1 , A. Bouché1 , V. Morillo1 , C. Casillas2 , J. López3 , R. LOZOYA4 ,E. BOLDO5
1
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofRadiation Oncology, Castelló de la Plana, Spain
2
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofRadiology, Castelló de la Plana, Spain
3
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofMedical Physics in Radiation Oncology, Castelló de la Plana, Spain
4
H OSPITAL P ROVINCIAL DE C ASTELLON, Department of Surgical Oncology,
CASTELLON, Spain
5
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofSurgical Oncology, Castelló de la Plana, Spain
Purpose: IOERT is a therapeutic variety of selective overimpression on tumoral volumes or area at relapse risk. That allows to protect the adjacenthealthy tissues.The purpose of this study was the assessment of toxicity andsurvival of intra-operative radiotherapy in exclusive treatment or overimpression of primary tumors and relapse.
Materials: Retrospective study carried out between February 2008 and December 2010 in 29 patients who were administered IOERT as part of multidisciplinary treatment. 72.4% were women and 27.6% men. The median age
was 63 years (range 38-82).The classification according to the localization
was: 41.4% breast, 34.4% colon-rectal, upper limb 10.3%, lower limb 6.8%,
gynaecological: 3.4% and pancreas 3.4%. 58.6% were administered IOERT
as primary treatment, 4 patients as overimpression (9 Gy) and 8 as exclusive
treatment (21 Gy). 82.8% showed R0 after surgery.The most frequently useddiameter of the applicator was 6 cm (27.6%) and the electron energy: 6-15
MeV. The dose varies according to the intention (9-21 Gy, median 14.92 Gy)
and the surgical margin. 27.6% were administered later external radiotherapy
as adjuvant treatment (median dose 44.5 Gy).
Results: With a median 34 month, the current overall survival was 75.9%. The disease free survival (DFS) and the nodal relapse were 79.3% and89.7%, respectively. The current local control was 93.1% with no statisticallysignificant differences between primary versus relapse. Of the patients withrelapse after treatment, 60% received chemotherapy with criteria of diseaseprogresion at 60%. Three of those patients (10.3%) died due to surgicalcomplications. The maximum acute toxicity was GII: dermatitis 27.6%, genitourinary 10.3% and moderate limitation in mobility was 6.8%. Two patients
presented neuropatic pain GIII with improvement one month after treatmentend. No later complications have been assessed because of the short monitoring period.
Conclusions: The use of IOERT, either as a relapse treatment or primarytumor (exclusive or overdosing on surgical bed) offers acceptable results oflocal control. It minimizes toxicity and the duration of the treatment.

S 248B RACHYTHERAPY: B REAST C ANCERS ARCOMA , H EAD N ECK , CNS-T UMORS

Sarcoma,Tumors

Head

Neck,

CNS-

604 poster
COLLAGEN MESH SHOULD BE USED FOR ABDOMINAL WALL
REPAIR AFTER SURGERY AND IORT
E. BOLDO1 , R. LOZOYA1 , G. PEREZ DE LUCIA1 , A. Bouché2 , V. Morillo2 ,F. Carlos2
1
H OSPITAL P ROVINCIAL DE C ASTELLON, SURGICAL ONCOLOGY UNIT,
CASTELLON, Spain
2
H OSPITAL P ROVINCIAL DE C ASTELLON, Radiation Oncology, CASTELLON,
Spain
Purpose: Covering extensive defects after wide margin surgery always represents a challenge in the management of groin sarcoma patients. Besides,
transportation of the patient out of the pro-sterile OR ambiance and exposureof the operative field for intraoperative radiotherapy (IORT) increases the riskof operative site infection (OSI). The paradigm of imperative need of a meshin a prone to infection area needs to be solved. Collagen meshes are indicated for abdominal wall repairs with high risk of infection. We report the useof this type of meshes as a possible solution for these IORT candidates.
Materials: We report a case of a 58 y.o. male patient presenting a recurrent
left groin sarcoma (fig 1). The patient had been operated in another center
twice. Pathological examination of the previous surgeries reported fusiform
type sarcoma. The day of surgery, prophilactic antibiotics (3rd generation
cephalosporin) were given. After 6 hours of surgical procedure another doseof antibiotics was administered. Collagen mesh repair was planed as risk factors for OSI (cancer patient, long and extensive operative procedure, transferof the patient to RT suite, flap viability and prolonged drain) were present.
Results: After wide margin surgery (abdominal wall, inguinal canal and left
orquiectomy) and IORT, a collagen mesh (Collamed, Bard Inc, Falstag USA)was used to substitute the resected inguinal fasciae and muscles (fig 2). The
area was covered with a free flap (fig 2). The patient was reoperated due
to flap necrosis and an abdominoplasty was performed. OSI (E. Coli) was
discovered in the 12th postoperative day (fig 3). The patient was put on antibiotics and the wound drained. After discharge, a follow up CT demonstrated
complete re-absorption of the mesh (Fig 4).
Conclusions: In case of abdominal wall repair needed after IORT, use ofcollagen (or other biological type) meshes should be considered, given thetheoretical increased risk of OSI.
605 poster
GLIOBLASTOMA MULTIFORME IN CHILDREN: PROGNOSTIC
FACTORS & SURVIVAL
I. Haider1 , U. Majeed2
1
S HAUKAT K HANUM C ANCER H OSPITAL, Lahore, Pakistan
2
P OLOKWANE R ADIATION O NCOLOGY, Department of Radiation Oncology,
Polokwane, South Africa
Purpose: Glioblastoma multiforme, a malignant tumor of neuroepithelial origin, is relatively uncommon in childhood and accounts for 7%-9% of intracranial tumors. The outcome in children is generally thought to be more favorable
than in adults.A retrospective study was conducted in order to determine clinical characteristics, prognostic factors and survival in Glioblastoma patientstreated in Shaukat Khanum Memorial Cancer Hospital & Research Centre
Lahore.
Materials: Fifteen pediatric patients with Glioblastoma treated from January
2006 to December 2009 were included in this retrospective study. Medianage was 10 years (range 4-17 years). The male to female ratio was 1.5:1.
The mean clinical history was 2 months (range 1-5 months). Intracranial hypertension was present in all cases, associated with long tract signs in 2 andcranial nerve involvement in 3 patients. The tumor site was frontal lobe 4,
temporal 3, parietal 5, cerebeller 1 and frontoparietal lobe in 1 patient. All
patients underwent surgery (Gross Total resection 3, Subtotal resection 7,
biopsy only 5 patients) followed by fractionated radiotherapy median dose
50.2Gy (range 30-60Gy).
Results: The overall median survival was 14 months (Range 2-53 months).
67% of patients achieved radiological response (Complete Response 13%,
Partial Response 20% and Stable Disease 34%) and 70% achieve durable
symptoms palliation 6 weeks following radiotherapy. On univariate analysis
female sex, duration of symptoms >2 months and extent of surgery wereassociated with better prognosis (p=0.03, p=0.09 and 0.01 respectively) andno factor was found significant on multivariate analysis.
Conclusions: Glioblastoma multiforme remains an important cause of morbidity and mortality in children. The overall prognosis is dismal. Multidisciplinary therapy including maximum safe resection and adjuvant radiotherapeutic and chemotheurapeutic approaches can significantly prolong survivalwith good quality of life.

606 poster
OUT COME OF GLIOBLASTOMA MULTIFORME IN ADULTS
U. Masood1 , I. Haider1
1
S HAUKAT K HANUM C ANCER H OSPITAL, Lahore, Pakistan
Purpose: Glioblastoma multiforme (GBM) is the most common and most malignant primary intracranial tumor. The prognosis of Glioblastoma Multiforme(GBM) remains very poor despite aggressive treatment with surgery, radiation, chemotherapy and novel therapeutic strategies. The aim of this study
was to analyze the prognostic factors & survival of GBM patients treated at
our institution.
Materials: The SKMCH & RC Cancer Registry was accessed and 51 patients of GBM treated in our institution were identified between Jan 2006 to
May 2010. Surgery was performed in 49 patients (8 gross total resection
and 41 subtotal resection) while 2 patients were surgically unresectable. All
patients received radiotherapy (8 patients were given conventional radiotherapy 60Gy/30 fractions at 2Gy per fraction over a period of 6 weeks while 43
patients treated with hypofractionated regimen 48Gy/16 fractions at 3Gy per
fraction over a period of 3 weeks.
Results: Median age at diagnosis was 47 Years (Range 18-73) and Male tofemale ratio was 3:1. ECOG performance status 0, I, II was 24%, 16% and
11% respectively. Radiological response was 64% (Partial response 34% andstable disease in 30%) and 36% had progressive disease on MRI which wasdone 3 months following completion of radiotherapy. On Univariate analysis
ECOG performance status, extent of surgical resection and response following radiotherapy were significant prognostic factors (P=0.003, P=0.01 and
0.002 respectively). Median over all survival for all patients was 8 months.
Conclusions: The outcome of GBM remains poor despite adequate surgical resection and good radiotherapy techniques. Extent of surgery and theperformance status were the most important prognostic factors. Improved
outcome with the use of temozolamide is a step forward in this regard.

GEC-ESTRO Meeting

S 249

Brachytherapy: Breast Cancer
607 poster
3D INTERSTITIAL HDR BRACHYTERAPHY BOOST IN THE CONSERVATIVE TREATMENT OF BREAST CANCER
M. Kubaszewska1 , J. Kobzda1 , A. Szymil1
1
E UROMEDIC, Brachytherapy, Poznan, Poland
Purpose: We present our protocol to treat the tumor bed as a boost after
breast conservative therapy (BCT) in early-stage breast cancer (BC) using
high dose rate brachytherapy (HDRB) based on pre and post implant computed tomography (CT) imaging.
Materials: Between October 2009 and October 2010, a total number of 46 female patients with stage I to II BC underwent BCT including: sparing surgery;whole breast irradiation and HDRB as the tumor bed irradiation. The boost
dose was 10 Gy. Flexitron HDR remote afterloading equipment with Iridium192 isotope was applied. The HDRB procedure consisted of: patient selection based on clinical, surgical, histological report; pre-implant CT-based
simulation to detect and localize titanium clips which define the tumor bed
after closed cavity surgery; implantation technique conducted under generalanesthesia; post-implant CT reconstruction of implant geometry with a 2 mm
slice separation, electronically transferred to 3-dimensional (3D) brachytherapy planning system; CT-based calculation and optimization of 3D physicaldose distribution. 6 to 17 needles spaced 15 mm apart were usually required. In 13 patients the needles were replaced with flexible catheters, fixedby plastic buttons. Double and triple plane implants were used in 17, and16 cases respectively. The treatment planning was based on the CT guided
3D reconstruction of the surgical clips, implant catheters/needles and criticalstructures localization (skin, lung, thoracic wall muscle and ribs). Target volume definition as the clinical target volume (CTV) was defined with a marginof 1-2 cm of breast tissue surrounding the primary tumor bed.
Results: We obtained following results of selected parameters from evaluation of DVH:

Conclusions:
1. Two sets (pre-implant and post-implant) of CT scans were required to
improve the implant quality,
2. The irregular 3D shape of the TV and the normal tissue structures
could be correctly localized on the basis of visual information obtained
from cross-sectional CT-imaging.
3. The use of surgical clips and CT imaging technique to demarcate tumor bed could substantially increase the accuracy in determining theboost volume, increasing the probability of local tumor control and decreasing undesirable cosmetic results.
4. The flexible implants were better tolerated by the patient, but it wasoften impossible to keep optimum geometry of rigid needles.
5. V200 and V300 decreased in higher number of planes and in rigid
implants instead of flexible, which might have an influence on late cosmetic side effects.

608 poster
A NUMERICAL CRITERION FOR FILLING OF MAMMOSITE´SBALLOONR. Díaz Fuentes1 , T. Murillo1 , E. Cabello Murillo1 , A. Ferrando Sanchez1 , F.
Clemente Gutierrez1 , M. A. De la Casa de Julian1 , J. C. Ramirez Ros1 , P.
Adaimi Hernandez1
1
H OSPITAL U NIVERSITARIO 12 DE OCTUBRE, Madrid, Spain
Purpose: To develop an equation of the minimum balloon volume required in
mammosite technique to irradiate adequately the clinic target volume (CTV),
based on the deformation of the lumpectomy cavity caused by the balloon
filling effect.
Materials: Interstitial is the most popular brachytherapical technique in Europe for partial breast irradiation. CTV for interstitial brachytherapy is usually defined as 1.5 cm margin volume enveloping the lumpectomy cavity(RTOG0413). However, dose prescription in mammosite is taken at 1 cm
from balloon’s border. Difference is justified if the 1.5 cm tissue ring aroundS 250B RACHYTHERAPY: B REAST C ANCER

B RACHYTHERAPY: B REAST C ANCER

the lumpectomy cavity is comprised at least 0.5 cm in radial direction by theballoon pressure. Although breast tissue is essentially uncompressible, i.e.
density is nearby constant, it can be stretched. Let us consider CTV as aspherical crown of 1.5 cm width around a theoretical spherical lumpectomy
cavity with radius RCAV. If the cavity radius were expanded by the balloon,
CTV would be contained into a spherical crown of 1 cm width at some balloon radius, RBALLOON > RCAV. In this way, the minimum balloon volume
required to cover up CTV by the prescription dose can be calculated as acavity volume function.
Results: An approximate solution is (volume unit in cc): VBALLOON
0.52(1.46VCAV 0.33 + 1.59)3 [eq. 1]. If we consider also air or seroma inside the CTV up to 10% in volume, uniformly distributed on a ring fitted to theballoon, we obtain: VBALLOON 0.52(1.42VCAV 0.33 + 1.26)3 [eq 2]. Exactcalculations (points) and approximations (continuous curves) for both cases
are showed in the graph. Horizontal lines indicate the available diameter
range of spherical mammosite balloons: 4-5 cm and 5-6 cm.

Conclusions: We think it’s important including the minimum volume balloon
among the usual acceptation criteria of mammosite implants. The volume ofthe surgically extracted piece is described in the anatomo-pathologiycal report and the balloon volume is determined by TC image, therefore verification
is easy. The optimum filling is just the one for which real CTV is encompassed
into 1 cm ring, but some additional safety margin is needed. Lumpectomy
cavity deviation from the spherical shape increases the necessary filling. The
same when there is no uniform air/seroma distribution. For this reason, we
consider that eq 2 yields a reasonable value whenever air/seroma is small or
relatively uniform.
609 poster
ACCELERATED PARTIAL BREAST IRRADIATION IN THE TREATMENT OF EARLY STAGE BREAST CANCER
R. Bilimagga1 , S. PS1 , G. SP1
1

B ANGALORE I NSTITUTE OF O NCOLOGY, Radiation Oncology, Bangalore,
India
Purpose: To determine the feasibility and effectiveness of Accelerated Partial
Breast Irradiation in patients with early stage breast cancer.
Materials: A total of 11 patients were treated with Accelerated Partial Breast
Irradiation during 2009 & 2010. 6 patients had T1N0M0 disease. 5 patients
had T2N0M0 disease. Interstitial implantation brachytherapy was used as a
Modality of Accelerated Partial Breast Irradiation. Dose given was 34Gy in 10
fractions. Local control and cosmesis were used as end points.
Results: A good local control and excellent cosmesis was achieved in all thepatients. No toxicities were observed.
Conclusions: Interstitial Implant brachytherapy is a safe and effective treatment modality for Accelerated Partial Breast Irradiation. It is well tolerated
treatment with a good local control and an excellent cosmesis.
610 poster

ACCELERATED PARTIAL BREAST IRRADIATION: A DOSIMETRICCOMPARISON OF PERI- AND POSTOPERATIVE IMPLANTS
K. Loessl1 , N. Cihoric1 , B. Isaak2 , D. Terribilini2 , D. M. Aebersold1
1
I NSELSPITAL , U NIVERSITÄT B ERN, Universitätsklinik für Radioonkologie,Bern, Switzerland
2
I NSELSPITAL , U NIVERSITÄT B ERN, Abteilung für Medizinische Strahlenphysik, Bern, Switzerland
Purpose: The use of brachytherapy in the management of breast cancer has
increased for accelerated partial breast irradiation (APBI) outside of clinical
trials. A main argument for APBI is to shorten the treatment time of adjuvant
radiotherapy in breast conserving treatment for better convenience especiallyin elderly patients with co-morbidities. These shorter courses of higher dose
fractions of multi-catheter-brachytherapy imply a quality assurance to receive
an acceptable cosmetic outcome. The objective of this study was to compare
the dosimetric analyses of the two treatment groups with perioperative andpostoperative delayed interstitial implants.

Materials: A dosimetric comparison of interstitial HDR brachytherapy for accelerated partial breast irradiation analogue to the GEC-ESTRO-APBI-Trial
was performed. Between 2007 and 2010 we implanted plastic tubes (in median 14 tubes in 3 planes) in 50 patients (pts) with newly diagnosed breast
cancer after breast conserving surgery for HDR-brachytherapy delivered with
Ir-192. 25 pts received implantation in a time-delayed setting (postoperative= group A), 25 pts were implanted peri-operative (during primary surgery =group B). After CT-image-based planning the target volume was defined as
the excision cavity marked by surgical clips plus a 2 cm margin. The prescription dose to the planning target volume (ptv) was 4 Gy per fraction for 8
fractions twice daily to a total dose of 32 Gy. Dosimetric analyses and earlyclinical outcome were compared.
Results: With a median follow-up of 15 months (1-37 months) there wasno local recurrence, 1/50 pts with a locoregional lymph node relapse after negative sentinel resection. 2/25 pts presented impaired healing after seroma/haematoma in group B. 0/25 pts with any acute side effects ingroup A.1 pt (group B) developed a symptomatic fat necrosis after extensive
haematoma. We delineated a V(ptv) in median of 45 ccm for group A and 66
ccm for V(ptv) for group B. With respect to the target volume, a median of 90.8
% (range 88-94%) for group A and 91.2 % (range 88-96%) for group B of thisvolume received 100% of the prescribed dose (Dref) (coverage index). The
median percentage of volume receiving 150% of the Dref was 27 % in group
A und 31 % in group B. However, there were no differences in further indexes
for conformity and homogeneity (median DNR: 0.31, DHI: 0.63, COIN: 0.71)
in the two groups.
Conclusions: The dosimetric quality and target volume coverage represented in the two different implant groups were similar. The data demonstrated that it is possible to receive a comparable geometrical implantation for
the required quality assurance for multi-catheter-HDR-brachytherapy in accelerated partial breast irradiation in the peri-operative situation versus theroutine post-operative implantation. As expected, the peri-operative impaired
wound healing and the absolute delineated target volume were higher in theperi-operative implanted group. A longer follow-up is needed for evaluation
for increased late side-effects.
611 poster
ANDROGEN DEPRIVATION THERAPY (ADT) FOR SALVAGE TREATMENT OF PSA ONLY RECURRENT PROSTATE CANCER AFTER
INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY FOREARLY STAGE PROSTATE CANCER : MEDIAN 6 YEAR FOLLOW-UP
IN 26 PATIENTS
I. Garcia1 , R. Mark2 , R. Akins3 , M. Nair1
1
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology and Image, Lubbock, Texas, USA
2
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology and Department of Medical Physics, Lubbock, Texas,
USA
3
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology and Image-Applied Medicine, Lubbock, Texas, USA
Purpose: Salvage treatment of biochemical recurrence after radiation implant is a subject of considerable controversy. Management options include PSA surveillance, radical prostatectomy, cryosurgery, External Radiation Therapy (XRT), Intensity Modulated Radiation Therapy (IMRT), and Androgen Deprivation Therapy (ADT). Complication risks after radical prostatectomy, cryosurgery, XRT and IMRT salvage can be significant. We present
our results in 26 patients treated with ADT for biochemical recurrence afterHigh Dose Rate (HDR) implant.
Materials: Between 1997 and 2010, 319 patients with T1 and T2 localized
prostate underwent TRUS guided interstitial implant, under spinal anesthetic
or local anesthetic. There were no Gleason Score or PSA exclusions. No patient received XRT, IMRT, or initial ADT. Median Gleason Score was 7 (range: 4 to 10). Median PSA was 9.3 (2.7 to 39.8). At last follow-up, 36 patients
had developed PSA only relapse. After a discussion of management options,
26 patients elected salvage treatment with intermittent ADT, starting with Casodex. All patients started Casodex 50 mg qd with PSA < 10.
Results: With a median follow-up of 72 months (range : 8 months to 150
months), the PSA control rate on Casodex was 84.6% (22/26). Four patients
have become refractory to Casodex, and were switched to Lupron. Two ofthese patients remain controlled on Lupron. One patient has entered a clinical
trial for Chemotherapy. Two patients have died from metastatic prostate cancer. One patient developed bone metastases, which have cleared on Lupron.
Side effects have been acceptable. One patient sustained a myocardial infarction, and a 2nd suffered a fractured hip.
Conclusions: With median 6 year follow-up, ADT appears to be a reasonable salvage option for patients experiencing a PSA only relapse after HDR
implant.

612 poster
CLINICAL RESULTS OF THE COMBINED TREATMENT INCLUDINGINTRALUMINAL CF-252 BRACHYTHERAPY FOR BREAST CANCER
V. Nevulis - Obuchovska1 , E. Aleknavicius1 , V. Atkocius1 , K. P. Valuckas1 ,V. Ostapenko1 , I. Kuzmickiene1
1
I NSTITUTE OF O NCOLOGY V ILNIUS U NIVERSITY, Vilnius, Lithuania
Purpose: The aim of this study was to evaluate the impact the preoperative radiotherapy including intraluminal Cf-252 brachytherapy on risk of locoregional recurrence and long-term survival in breast cancer patients treatedwith mastectomy in 1987-1997.
Materials: Weretrospectively reviewed records for 155 patientswith invasive
medial and central breast cancer (T1-T3, N0-2) who received preoperative
irradiation of the chest wall, axillary, and supraclavicular, and parasternal regions and underwentmastectomy.Median age was 55 years, 56.5 % of the patients were lymph node negative. Patients received of conventional 36-45 Gy
radiation dose in 2-Gy fractions and intraluminal Cf-252 neutron brachytherapy to parasternal lymph nodes. During surgery catheters were placed in thearteria thoracica interna and on the first or second post-operative day, flexible
Cf-252 sources were inserted into catheters. Their active length was 10-12cm, irradiation dose at a distance of 1 cm from the centre of source was 4045 Gyeq. There was no Tamoxifen given. The five-year actuarial and 10-yearof loco-regional recurrence and survival probabilities were estimated by the
Kaplan-Meier method and differences between patient subgroups were compared by the log-rank test.
Results: Overall survival was 73.8, 72.2 and 44.0% at 3, 5 and 10 years.
The 5-yer acturial overall survival was 38% for patients with chest wall, axillary, supraclavicular or internal mammary lymph node (one case) recurrence.
Recurrence was observed in 31 of 154 (20 %) patients at the end of thisstudy. Loco-regional recurrence rate was 7.4, 13.9 and 20.4% at 3, 5 and10 years. The recurrence rate was 1.96% in patients without lymphovascularpermeation, and it increased to 21.36 % in patients with in patients with lymphovascular permeation (p=0.03). Patients younger than 50 years at primary
diagnosis had statistically significantly higher rates of 10 year recurrence [16of 53 (30.2%)] than older patients [15 of 101 (15 %)], p=0.03. The side effects
included of pneumonitis (3 cases, 1.9%), lung fibrosis (26 cases, 16.8 %) andoedema of the arm (37 cases, 23.9%).
Conclusions: The long-term data show that the preoperative radiotherapy
including intraluminal Cf-252 brachytherapy has positive impact on time ofloco-regional recurrence and survival in patients after mastectomy.
613 poster
COMPARISON BETWEEN VOLUME AND GEOMETRICAL OPTIMIZATION IN CT BASED HDR BREAST IMPLANTS AND ITS IMPACT
ON COSMETIC OUTCOME
S. Saha1 , A. Gangopadhyay2 , P. Chatterjee1 , K. Ghosh3
1
AMRI H OSPITALS, Radiotherapy, Kolkata, India
2
M EDICAL C OLLEGE KOLKATA, Radiotherapy, Kolkata, India
3
M EDICAL C OLLEGE & H OSPITAL, Radiotherapy, Kolkata, India
Purpose: The goal of HDR breast implant is to attain good cosmesis, in addition to local control. Prudent optimisation in a comprehensive plan is thecorner stone of a good implant. When PTV definition and delineation are
possible - as with CT based planning, volume optimization with fine tuning(VO) is considered much conformal than geometrical optimisation (GO). In
spite of this, most centres apply GO for individualized image based planningof breast implants, possibly due to time constraints. This work aims to compare GO with VO for HDR breast implants in terms of conformity and dose
homogeneity parameters (as per ICRU 58) and also to find its impact on clinical outcome mostly on long term cosmesis..
Materials: 31 HDR interstitial breast implants (Boost= 27, PBI = 4) were enrolled in this study between July 2006 and September 2007: 21 had 2-planeand 10 had 3-plane insertions. Target volume, implant planes necessary andorientation of needle entry and exit points were conceived from pre-implant
CT scan. Individual post insertion CT - based planning was done. Following applicator contouring, marking of active lengths and contouring of CTV
using Varian Brachyvision software, two computer planning options- GO and
VO were compared for each treatment. V100, D90, V150, V200, DHI, DNR,
Coverage index, Dskin and Dchest wall were recorded for comparison, alongwith conformity parameters viz. COIN.25/31 patients were treated with GO
and remaining 6 were with VO.
Results: Both optimization options achieved almost similar V100 of median
93% (88 - 97). D90 for VO plans was slightly higher (median 98%) against
median 94% for GO plans. With VO, high dose volumes were markedly lower
as evidenced by V150 (24% with VO vs. 46% with GO) and V200 (7% with
VO vs. 12% with GO). Dose homogeneity was improved with VO (Dose homogeneity Index - DHI = 0.73 against 0.53 with GO).Volume optimization alsooffered better conformity (median COIN= 0.79 for VO vs. 0.67 for GO). Doseto OARs was also found lower with VO. Skin dose rose from median 34%
in VO to 41% in GO plans. Chest wall dose was evidently higher with GOplans (median 24% compared to 18% for VO). After a median follow up of 48
months only 2 patients had in-breast failure. Grade 1-2 fibrosis was noted in

S 251

19/25 with GO and 1/6 with VO. (P= 0.013). Gr.1-2 telengiectasia occurredin 3/25 with GO vs. 1/6 in Arm II (P= NS). Grade 3 fibrosis was observedin 2 patients with GO and in none with VO. Regarding cosmetic outcome,14/25 patients (56%) were good + excellent, 11 fair and none poor with GO.
Corresponding figures with VO were 5/6 (83%), 1/6 and 0/6 (P = NS).
Conclusions: Both conformity and dose homogeneity parameters favored
volume optimization for each insertion, as also dose to skin and chest wall.
Consequently late toxicity mainly fibrosis- was significantly more with geometrical optimization and cosmetic outcome is likely to improve with volume
optimization with fine tuning, although it is significantly more time consuming
than geometrical optimization.
614 poster
COSMETIC OUTCOME AFTER TARGIT COMPARED WITH EXTERNAL BEAM RADIOTHERAPY FOR EARLY BREAST CANCER
M. Keshtgar1 , N. Williams1 , T. Corica2 , C. Saunders3 , D. Joseph2 , M.
Bulsara4
1
R OYAL F REE AND UCL M EDICAL S CHOOL, Department of Surgery,
London, United Kingdom
2
S IR C HARLES G AIRDNER H OSPITAL, Department of Radiotherapy, Perth,
Australia
3
S IR C HARLES G AIRDNER H OSPITAL, Department of Surgery, Perth,
Australia
4
U NIVERSITY OF N OTRE DAME, Institute of Health and Rehabilitation
Research, Fremantle, Australia
Purpose: The randomised controlled TARGIT Trial was designed to determine non-inferiority between the novel technique of TARGIT [intra-operative
radiotherapy with Intrabeam®(Carl Zeiss, Germany)] and conventional external beam radiotherapy (EBRT) in women with early breast cancer. The main
outcome objective is risk of local relapse within the treated breast. We report here data from a sub-protocol assessing cosmesis in 114 women over
50 years of age participating in the TARGIT Trial from one centre (Perth, Australia).
Materials: Frontal digital photographs from were assessed, blind to treatment, using specialist software (BCCT.core 2.0, INESC Porto, Portugal)
which produces a composite score based on symmetry, colour and scar. Statistical analysis was by generalised estimating equations (GEE) on all of thedata, and logistic regression analysis at year 1.
Results: 114 patients have been assessed, median age at randomisation 62
years (IQR 56 to 68). Photographs were taken at baseline (before surgery)and one, two, three and four years after initial breast conserving surgery;none had subsequent breast surgery. The scores were dichotomised into Excellent and Good (EG), and Fair and Poor (FP). There was a non-significant
45% increase in the odds of having an outcome of EG for patients in the TARGIT group relative to the EBRT group (OR=1.45, 95%CI 0.78 2.69, p=0.245)
after adjusting for tumour size. The results were similar when adjusted fortumour grade and age of the patient. For year 1 only there was a statisticallysignificant 2.35 fold increase in the odds of having an outcome of EG for patients in the TARGIT group relative to the EBRT group (OR=2.35, 95%CI 1.02
5.45, p=0.047) after adjusting for age of the patient, tumour size and grade.
Conclusions: These results confirm a significantly better cosmetic outcome
with TARGIT compared to EBRT in the first year after surgery.
615 poster
DOSIMETRIC CHARACTERISTICS OF ACCELERATED PARTIAL
BREAST IRRADIATION WITH CT IMAGE-BASED MULTI-CATHETER
INTERSTITIAL BRACHYTHERAPY: A SINGLE INSITUTION’SEXPERIENCE
T. Major1 , G. Fröhlich1 , C. Polgár1
1
N ATIONAL I NSTITUTE OF O NCOLOGY, Department of Radiotherapy,
Budapest, Hungary

Purpose: To present dosimetric assessment of CT-based high-dose-rateinterstitial brachytherapy of breast cancer including dose-volume histogram
analysis of dose to critical structures.
Materials: Treatment plans of forty-nine patients with early-stage breast cancer enrolled to the GEC-ESTRO Phase III. clinical trial and treated with interstitial partial-breast irradiation were selected for the study. Treatment planningwas performed with the use of pre- and postimplant CT imaging. Quantitative
dosimetry on target volume including calculation of target volume coverage,
dose homogeneity and conformality indices was performed. Detailed DVH
analysis was carried out to characterize the dose to breast, lung and heart.
Results: Three-, four-, five, and six-plane implants were used in 17, 21, 10
and 1 patients, respectively. The median number of catheters was 15 (range
6-28). The mean volume of the PTV was 66.4 cm3 (range 15.5-176 cm3 ).
On average, 92% (range 90-96%) of the PTV received the prescribed dose.
The mean values for DNR and DHI for target were 0.32 (range 0.25-0.41)
and 0.65 (range 0.50-0.76), respectively. The mean COIN was 0.68 (range
0.51-0.82), and breast tissue volume around PTV which received at least theprescribed dose ranged between 5.3 and 51 cm3 . The mean maximum doseS 252B RACHYTHERAPY: B REAST C ANCER

B RACHYTHERAPY: B REAST C ANCER

to skin, lung and heart were 55%, 44% and 21%, respectively. Volumes ofthe lung and heart receiving 5 Gy were 50.6 cm3 and 12.8 cm3 , and for 10
Gy 6.7 cm3 and 0.3 cm3 respectively. The V10 for lung was 16% and V5 forheart was 47%.
Conclusions: The implant technique based on two sets of CT scanning resulted in acceptable dose distributions with respect to target coverage, dose
homogeneity and conformality. Volumetric evaluation of dose to critical structures provides the possibilities to correlate the doses to side effects.

The mean values of PTVref and PTVmin have increased from 74,8% to 95,5%and from 40,6% to 72,3% respectively, since 2006. DHI was at the 0,7 levelin the period of 2D guided treatment planning and drop significantly whentreatment plans based on CT scan were introduced. However, it should bepointed out that DHI has constantly increased since 2009 and now the levelof dose homogeneity is satisfactory. In the 2D era only implant parameters
could be evaluated. None of PTV correlated parameters were estimated atthat period. COIN is the only parameter that hasn’t evolved yet. Its value
oscillate between 0,57 and 0,62.
Conclusions: All changes that have been introduced to APBI method have
led to higher treatment plans quality. However, our experience shows that
improvement of some parameters is still required.

616 poster
DOSIMETRIC COMPARISON OF EXTERNAL RADIOTHERAPYTECHNIQUES AND HIGH DOSE RATE BRACHYTHERAPY FOR
BREAST CANCER BOOST
Senkesen1 , H. Kucucuk1 , I. S. Aslay2 , E. Tezcanli3 , E. Goksel1 , M.

618 poster

Garipagaoglu3 , M. Sengoz3
ACIBADEM KOZYATAGI H OSPITAL, Department of Radiation Oncology,
Kozyatagi - Istanbul, Turkey
2
I STANBUL U NIVERSITY O NCOLOGY I NSTITUTE, Department of Radiation
Oncology, Istanbul, Turkey
3
ACIBADEM U NIVERSITY, Department of Radiation Oncology, Istanbul,
Turkey1

Purpose: The addition of a tumor bed boost after whole breast radiotherapy(WBRT) has been shown to improve local control in breast cancer patients.
Boost plans generated with photons or electrons usually result in inhomogeneous dose distributions within the tumor bed while increasing the doses inbreast volume. Breast brachytherapy (BT) might provide a better homogeneity within the tumor bed while reducing the dose in the breast tissue. In thisstudy, we aimed to compare dose-volume histograms of conformal external
radiotherapy plans with high dose rate (HDR) BT.
Materials: Four patients pathologically diagnosed with breast cancer underwent breast conserving surgery received WBRT followed by BT boost at our
institution. Boost plans were initially tailored with 16MeV electron beams for
3 of the patients and 18MV for 1 patient with ECLIPSE version 8.6 (Varian
Palo Alto USA) radiotherapy planning system, three dimensional conformalplanning was done to obtain dose - volume information. Boost plans weresummed up with WBRT plans in order to evaluate the dose distributions.
Given the large irradiated volumes and hot spots inside the breast tissue,
these patients were found to be candidates for BT boost. BT plans were generated via ECLIPSE BrachyVision treatment planning system and treatments
were applied with Varisource 200 HDR (Ir-192 source). Plastic catheters wereplaced in the breast depending on the location size and shape of the tumor
bed and geometrically adjusted in order to cover the tumor bed with the helpof a guiding template, under general anesthesia. The catheters were measured through the transfer cables connecting to the source. All patients were
scanned with a multi-detector 16 slice CT (Siemens sensation 16 Erlangen,Germany) with 3mm interval. Images were transferred as DICOM III format
via network between CT and ECLIPSE. The catheters were contoured andtheir positions within the breast were defined. Target volumes and organs at
risk (OAR) were delineated. Source lengths and their locations in the transfer cable were illustrated depending on the tumor size. Dose distribution was
manually optimized in order to achieve adequate tumor bed coverage. The
implantation and dose specifications were performed similar to the rules of
the Paris system. The minimum central dose (MCD) was defined by calculating the mean of basal doses while minimum peripheral dose (MPD) was
defined by calculating the 85% of mean basal dose. The total HDR boost
dose of 15Gy was delivered in 5 fractions of 3Gy MPD, two fractions a day, 8hours apart.
Results: Table1 summarizes the data for 4 cases including the MCD, MPD
and homogeneity index (HI) parameters. D90 is the dose received by the 90%of the volume, V100, V90 and V50 describe the volumes receiving the 100%,90% and 50% of the prescription dose, respectively. Lung dose changes
depending on the treatment technique are shown in table2.

Conclusions: Interstitial HDR BT provides a convenient method for boosting
the tumor bed following conformal whole breast irradiation without overdosing
normal tissues. The fractionation scheme of 15Gy in 5 fractions is well tolerated. Better cosmetic outcome in long term is shown in many studies as aresult of dose homogeneity and reduced radiated breast volume. Lung doses
are also minimal in BT because of its dosimetric features.
617 poster
DOSIMETRIC PARAMETERS OF 2D AND 3D PLANNING IN ACCELERATED PARTIAL BREAST IRRADIATION – GLIWICE EXPERIENCE
A. Cholewka1 , M. Szlag1 , B. Białas2 , S. Kellas-Sleczka2 , K. Slosarek1
1
C ENTER OF O NCOLOGY - MSC M EMORIAL I NSTITUTE, Department ofRadiotherapy and Brachytherapy Planning, Gliwice, Poland
2
C ENTER OF O NCOLOGY - MSC M EMORIAL I NSTITUTE, Brachytherapy
Department, Gliwice, Poland
Purpose: This study covers over five years of our clinical trials with accelerated partial breast irradiation method (APBI). Dosimetric and volumetricparameters of the treatment plans were evaluated.
Materials: APBI treatment plans and implantation technique have been constantly improved in Brachytherapy Department. At the beginning, orthogonalfilms (2D imaging) were taken for both treatment planning and pre-planning
procedure(preparation for implantation). Later on, we have introduced 3D
planning and pre-planning, based on CT scans, to APBI method. At present,
pre-planning is carried out in real time of implantation. Needles are inserted
and modified if necessary. Real time evaluation of the implant geometry is
performed with Cone Beam CT. Treatment plans, calculated for all patientstreated with APBI - BT from June 2006 till now, were used for this study.
Patients were divided into groups depending on periods of time when different imaging techniques were used for treatment planning and pre-planning
procedures. To evaluate progress we’ve made in our APBI procedure, following parameters were taken into account: percentage of the target volume
receiving the reference dose (PTVref), minimum dose in the target volume
expressed as a percentage of reference dose (PTVmin), dose homogeneity
index (DHI) and conformity index (COIN). According to the definition DHI=1(V150/Vref), where Vref and V150 quantify volumes receiving the reference
and 1,5 times of the reference dose respectively. The COIN defines coverageof the target volume by the reference isodose including unwanted irradiationof normal tissues and defined as COIN=(PTVref/Vref)(PTVref/VPTV). Meanvalues of the selected parameters were computed in each group.
Results:

FOUR-YEAR RESULTS USING BALLOON BASED BRACHYTHERAPY TO DELIVER APBI WITH A TWO-DAY DOSE FRACTIONATIONSCHEDULE
J. B. Wilkinson1 , A. Martinez1 , M. Ghilezan1 , C. Shah1 , M. Wallace1 , C.
Mitchell1 , E. Sebastian1 , A. Limbacher1 , P. Bentiez2 , E. Brown2 , I. Grills1 ,P. Chen1 , F. Vicini1
1
W ILLIAM B EAUMONT H OSPITAL, Department of Radiation Oncology, RoyalOak MI, USA
2
W ILLIAM B EAUMONT H OSPITAL, Department of Surgery, Royal Oak MI,
USA
Purpose: Patients with early-stage breast cancer treated with accelerated
partial breast irradiation (APBI) using brachytherapy in the United States traditionally receive 10 fractions over five days. We present four-year resultsfrom a Phase I/II trial using balloon-based brachytherapy to deliver accelerated partial breast irradiation (APBI) in two days.
Materials: Between March 2004 and August 2007, 45 patients received
breast-conserving surgery followed by adjuvant radiation therapy using aballoon-based brachytherapy applicator delivering 2800 cGy in four fractions
over two days. Negative surgical margins and a skin to balloon distance> 8mm were required for all patients. Toxicities were evaluated using the
National Cancer Institute Common Toxicity Criteria for Adverse Events v3.0
scale. Outcomes analyzed include toxicities scored using the CTC v3.0 scale,
ipsilateral breast tumor recurrence (IBTR), regional nodal failure (RNF), distant metastasis (DM), overall survival (OS), disease free survival (DFS), andcause specific survival (CSS).
Results: Median age was 66 years (range 48-83) and median tumor size was
0.6 cm (range 0.2-2.3 cm). Five percent of patients were node positive (n=2),
while 73% were estrogen receptor positive (n=33). Median follow up was 3.4
years (2.2-6.1 years) with greater than two years of follow up for all patients.
Only Grade 1 and Grade 2 toxicities were noted with fat necrosis (29%) andasymptomatic seromas (58%) being the most common toxicities. Seven percent of patients developed ipsilateral rib fractures (n=3), although this was notstatistically associated with maximum rib dose (p=0.31). Ninety eight percent
of patients had a good or excellent radiation-related cosmetic outcome at thetime of last follow up. There were no IBTRs or RNFs; however, two patientsdeveloped DMs. Four-year actuarial OS was 93%, DFS 96% and CSS was
100%. Most patients treated (64%, n=29) fell into the "cautionary" categoryof the ASTRO consensus statement (CS) for APBI, although assignment to a
CS category did not correlate with any negative clinical outcome.
Conclusions: Treatment of early-stage breast cancer patients with breast
conserving therapy using a two-day radiation dose schedule employing
balloon-based brachytherapy resulted in acceptable chronic toxicity and similar clinical outcomes as standard five-day fractionation.
619 poster
HIGH DOSE RATE BRACHYTHERAPY BOOST VERSUS ELECTRONBEAM BOOST IN THE TREATMENT OF EARLY BREAST CANCER OUR EXPERIENCE IN INDIAN FEMALES
A. R. Bhatnagar1 , R. Sharma1 , D. P. Singh1

S 253

patients in the implant group had increased fibrosis and pigmentation thanthe electron group.
Conclusions: Patients with early breast cancer after undergoing breast conserving surgery and whole breast irradiation have better cosmetic results andreduced chances of fibrosis when they are given electron boost as comparedto HDR BT boost. For local tumor control assessment long term follow up
studies are needed. Breast conservation therapy nowadays is an effective
treatment for early breast cancer with more and more patients preferring thisoption due to better psychosexual quality of life.
620 poster
INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY FOR
BREAST CANCER IN WOMEN < 50 YEARS OF AGE COMPARED TO> 50 YEARS OF AGE : MEDIAN 6 YEAR FOLLOW-UP IN 280 CASESUSING MULTI-CATHETER TECHNIQUE
A. Gipson1 , R. Mark2 , R. Akins2 , M. Nair3
1

J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Lubbock, Texas, USA
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, USA
3
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology Molecular Radiation Sciences, Lubbock, Texas, USA
2

Purpose: External Beam Radiation Therapy (EBRT) has been the standardof care for breast conservation radiation therapy, for more than 20 years. It is
well known that pre-menopausal women have a worse prognosis than postmenopausal women. However, it is also known that mastectomy does notconfer a better prognosis than breast conservation in these younger women.
Hence, the American College of Radiology does not have an age limit forbreast conservation candidacy. Recent data indicates that Interstitial Implantand High Dose Rate (HDR) radiation afterloading compares very favorably to
EBRT in early stage breast cancer. There is controversy regarding the useof HDR in patients < 50 years of age. We present our data in patients < 50years of age compared to > 50 years of age.
Materials: Patients with Tis, T1, and T2 tumors measuring < 4 cm, negative
surgical margins, and 1-3 positive axillary lymph nodes were judged to be
candidates for Interstitial Implant. Implants were performed under Stereotactic Mammographic guidance with conscious sedation and local anesthesia.
The implants were placed using the Anderson-Nair Template using from 3
to 8 planes, and 8 to 74 needles. Catheters were subsequently threaded
thru the needles, and the needles removed. Catheter spacing was 1.0 to 1.5
cm. Radiation Treatment planning was performed using CT Scanning and
the Plato System. Treatment volumes ranged from 25 cm3 to 359 cm3 . HDR
treatment was given using the Nucletron afterloading system. The breast implant volume received 3400 cGy in 10 fractions prescribed to the Planning
Target Volume, given BID over 5 days.
Results: Between 2000 and 2010, 280 patients underwent Interstitial HDR
Implant. The procedure was well tolerated. No patient required hospital admission. With a median follow-up 72 months (range 6-138 months), local
recurrence (LR) occurred in 4.3% (12/280). Cosmetic results were good to
excellent in 89.6% (251/280) of the patients. LR occurred in 6.1% (2/33) ofpatients < 50 years of age vs. 4.0% (10/247) in patients > 50 years of age(p = 0.63). There were no infections. Wound healing complications developed in 2.9% (8/280). Three of these patients had received anthracycline
based Chemotherapy. The other five had large (> 200 cm3 ) implant volumes,
catheter spacing of 1.5 cm, and V-150% of > 30%. Two patients healed after
6 months of conservative treatment. Surgery was required in six patients whodeveloped fat necrosis.
Conclusions: With median 72 month follow-up, Breast Conservation radiation therapy utilizing Interstitial Multi-Catheter HDR Implant has yielded local
recurrence rates and cosmetic results which compare favorably to EBRT in
selected patients. There was no statistically significant difference in LR between patients < 50 years of age vs. > 50 years of age. While there was atrend towards higher LR in patients < 50 years, LR appears comparable topatients treated with EBRT. Therefore, we believe that age < 50 years should
not be a contraindication for HDR for breast conservation.

1

S.M.S. M EDICAL C OLLEGE & ATTACHED H OSPITALS, Department ofRadiotherapy, Jaipur, India
Purpose: To evaluate the effect of high dose rate brachytherapy (HDR BT)
boost versus electron beam boost on local tumor control, side effects andcosmesis after breast conserving surgery in early breast cancer.
Materials: 40 women with Stage I-II breast cancer who underwent breast
conserving surgery were treated by 50 Gy adjuvant radiotherapy to the wholebreast and then randomly assigned to receive 15-16 Gy boost to the primarytumor bed either with HDR BT (n = 20) or electron beam using linear accelerator (n = 20). HDR BT was performed using interstitial Iridium-192 temporary
implants. Breast cancer related events, side effects and cosmetic results
were assessed after one and a half year.
Results: There was no significant difference in local tumor control between
patients treated with electron or HDR BT boost over a period of one and ahalf year in our study. Patients in the electron group had better cosmesis
than those in the implant group, which was statistically significant. However,621 poster
INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY FOR
DUCTAL CARCINOMA IN SITU OF THE BREAST : MEDIAN 6 YEARRESULTS OF 66 CASES USING MULTI-CATHETER TECHNIQUE
W. Vance1 , R. Mark1 , M. Nair1 , R. Akins1
1
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, USA
Purpose: External Beam Radiation Therapy (EBRT) has been the standardof care for breast conservation radiation therapy, in both Invasive Ductal Carcinoma (IDC) and Ductal Carcinoma In Situ (DCIS). Recent data indicatesthat Interstitial Implant and High Dose Rate (HDR) radiation afterloading compares favorably to EBRT in selected cases of IDC. There is little data regarding HDR in DCIS. Current ASTRO and American Brachytherapy Society
Guidelines consider DCIS an investigational category for primary HDR treat-S 254B RACHYTHERAPY: B REAST C ANCER

B RACHYTHERAPY: B REAST C ANCER

ment. Notably, DCIS is not a contraindication for EBRT. We report our HDR
results in 65 patients with DCIS.
Materials: Patients with Tis, T1, and T2 tumors measuring < 4 cm, negative
surgical margins, and < 3 axillary lymph nodes were judged to be candidates
for Interstitial Implant. Implants were performed under Stereotactic Mammographic guidance with conscious sedation and local anesthesia. The implants
were placed using a Template with from 3 to 8 planes, and 8 to 74 needles.
Catheters were subsequently threaded thru the needles, and the needles removed. Catheter spacing was 1.0 to 1.5 cm. Radiation Treatment planningwas performed using CT Scanning and the Plato System. Treatment volumes
ranged from 25 cm3 to 359 cm3 . HDR treatment was given using the Nucletron afterloading system. The breast implant volume received 3400 cGy in 10
fractions prescribed to the Planning Target Volume, given BID over 5 days.
Results: Between 2000 and 2010, 280 patients underwent Interstitial HDR
Implant. The procedure was well tolerated. No patient required hospital admission. With a median follow-up 72 months (range 6-138 months), local
recurrence (LR) occurred in 4.3% (12/280). LR occurred in 3.7% (8/214) ofpatients with IDC vs. 4.5% (3/66) in DCIS (p = 0.72). Cosmetic results weregood to excellent in 89.6% (251/280) of the patients. There were no infections. Wound healing complications developed in 2.9% (8/280). Three ofthese patients had received anthracycline based Chemotherapy. The otherfive had large (> 200 cm3 ) implant volumes, catheter spacing of 1.5 cm, andV-150% of > 30%. Two patients healed after 6 months of conservative treatment. Surgery was required in six patients who developed fat necrosis.
Conclusions: With median 72 month follow-up, Breast Conservation radiation therapy utilizing Interstitial Multi-Catheter HDR Implant has yielded local
recurrence rates and cosmetic results which compare favorably to EBRT in
selected patients. There was no difference in LR between patients with IDC
and DCIS. Based on this data, we believe that HDR should be considered a
primary breast conservation treatment option for patients with DCIS. Large(> 200 cm3 ) implant volumes, and V-150% > 30%, appear to be relative contraindications to Interstitial HDR Implant. Finally, catheter spacing of 1 cm
yielded optimal dosimetry and minimized complications. Compared to Mammosite and Contura techniques, the Interstitial Multi-Catheter method offers
greater flexibility of radiation delivery. Advantages include, no concern regarding surgical cavity shape irregularities, balloon conformality to surgicalcavity, balloon rupture, balloon movement, air gaps, hematoma, seroma, skinballoon proximity to skin, balloon shape distortion, and catheter movement
within the balloon.
622 poster
OPTIMISATION OF MAMMOSITE BRACHYTHERAPY
K. Eyre1 , D. Whitney1 , H. Chantler1 , C. Coles2 , C. Wilson2
1
A DDENBROOKE ’ S H OSPITAL, Department of Medical Physics and Radiation
Safety, Cambridge, United Kingdom
2
A DDENBROOKE ’ S H OSPITAL, Oncology, Cambridge, United Kingdom

Purpose: Current local practice for MammoSite Breast Brachytherapy follows
the protocol of the FORUM (Feasibility Of breast Radiotherapy Using MammoSite) trial, using 1 source dwell position at the centre of a single catheter.
There are physical and dosimetric limitations to this technique. Planning target volume (PTV) coverage is affected by the anisotropy of the 192 I sourcethat results in isodoses pulled in along the source axis. Inability to modify
dose distribution when the balloon is close to skin or asymmetrically inflated
can result in exclusion from the trial.This study investigated 2 solutions: (i) aline source plan (multiple dwells along a single catheter) to compensate forsource anisotropy and (ii) Multi-Lumen MammoSite to compensate for asymmetry.
Materials: The solutions were applied to datasets for 8 clinical patients, 3of whom were ineligible for the trial due to asymmetry.Inverse planning simulated annealing (IPSA) within Oncentra Masterplan was used to re-plandatasets using multiple sources along a single catheter. Inverse planning cancreate unexpected imperfect dosimetry. Therefore, the IPSA plans were used
to create a generic template of dwell positions and dwell weights for forward
planned MammoSite treatments. This generic line source was applied to all
patient datasets using same prescription point as the single source.Datasets
were planned a second time using a Multi-Lumen catheter. This consists ofa central catheter and 3 outer catheters arranged 3mm from the central one
and 120 degrees from each other. The generic line source was loaded onto
the central catheter and dwells in the outer catheters were optimised to compensate for balloon asymmetry and/or close skin proximity.The V100 (volumeof the PTV receiving 100% of the prescribed dose) and the Full Width Half
Maximum (FWHM) of the differential PTV DVH was calculated. The FWHM
measures the affect of the new techniques on the homogeneity of the dose
distribution.
Results: Table 1 shows results for the single source, line source and theMulti-Lumen plans. The generic line source plan increased the coverage of
the PTV in all cases compared to the single source plan. The Multi-Lumencatheter improved PTV coverage in all cases compared to the single sourceand produced equivalent or better coverage in 7/8 cases compared to thegeneric line source. The Multi-Lumen improved dose homogeneity as shownby the reduction in FWHM. Doses to the heart and lungs and volumes ofnormal tissue receiving 150% and 200% of the prescribed dose remained
within recommended constraints.

brachytherapy on the long term survival in central and medial breast cancer
patients treated with mastectomy.
Materials: Between January 1987 and December 1997, 418 patients with
Stage II and III breast carcinoma completed preoperative radiotherapy andmastectomy at the study institution. A retrospective analysis was conductedto compare the outcome of radiation therapy for the three groups: 237 patients have received hypofractionated radiotherapy (7 Gy twice or 4-5 fractions
by 5 Gy), 181 patients conventional preoperative radiotherapy (40 Gy in 20
fractions) to the chest wall, axillary, supraclavicular and parasternal regions.
145 patients from hypofractionated radiotherapy group underwent irradiationof the parasternal lymph node chain by the flexible interstitial Cf-252 sources
40 Gyeq 1 cm from central axis of the sources. Mean age 54.8 yr. The median of follow-up 8.4 yr. Overall survival was calculated from mastectomy todeath from any cause data. The Kaplan-Meier method with the log-rank test
was used for overall survival.
Results: At10 years, there was no statistically significant between groups.
The overall survival for stage II was 52%, 47%, 46% (p=0.46) and for stage
III was 31%, 31%, 29% (p=0.36) in groups of hypofractionated radiotherapy, conventional preoperative radiotherapy and hypofractionated radiotherapy with Cf-252 intraluminal brachytherapy respectively.
Conclusions: The long term survival data have demonstrate similar survival
rates in a trial hypofractionated and conventional premastectomy irradiationgroups of the patients with stage II and III breast cancer as well as for hypofractionated radiotherapy including intraluminal Cf-252 brachytherapy.
625 poster

Conclusions: Line source and Multi-Lumen techniques consistently improved the PTV coverage compared to the single source technique. In addition, dose optimisation using Multi-Lumen compensated for balloon asymmetry and close skin proximity so that patients previously excluded from the
FORUM trial would now be eligible for treatment.
623 poster
PHASE II STUDY WITH A SINGLE FRACTION OF HDR
BRACHYTHERAPY (FAST-BOOST) AFTER WHOLE BREAST
IRRADIATION IN EARLY BREAST CANCER. LONG-TERM RESULTS
J. L. Guinot1 , M. Carrascosa1 , M. Tortajada-Azcutia1 , M. Santos1 , P. Soler1 ,V. C. Contreras2 , L. A. Arribas1
1
I NSTITUTO VALENCIANO O NCOLOGIA, Department of Radiation Oncology,
Valencia, Spain
2
I NSTITUTO VALENCIANO O NCOLOGIA, Department of Radiation Physics
and Radiation Safety, Valencia, Spain
Purpose: We present the outcome at ten-year follow-up of a prospective
study about 192-Ir high dose rate brachytherapy (HDR) with a single fraction
as a boost after whole breast irradiation in breast-conserving therapy.
Materials: During 1999 and 2000, 84 consecutive patients with invasive
breast cancer after conservative surgery were treated with 6 MV photon external beam radiotherapy (EBRT) to achieve 46 Gy to the whole breast. One-two
weeks later, an implant with parallel metallic needles was performed under local anaesthesia and sedation in an outpatient basis. A free margin of morethan 4mm was required. All cases were stages T1-2 but one case T3. There
was node involvement in 19%. Chemotherapy was previously used in 47%
and hormonal therapy in 87%. A single dose of 7 Gy (HDR) with optimizationin volume was prescribed to the 90% isodose. Implant volume was decided byclinical assessment. No simulation or CT scan was performed, and dosimetry
was calculated theoretically. We have named this technique as "FAST-boost",
because the whole treatment is delivered in 2-3 hours.
Results: The median follow-up was 120 months. Three patients relapsedin the margin of the implant and two in a different quadrant with an actuarial
local control of 98.5% and 95.6% at five and ten year. Breast control was
97.4% and 92.6%. Eleven patients developed distant metastasis. Disease
free survival was 90.2% and 79.9% and overall survival 92.7% and 90.2%.
Cosmetic results were good or excellent in 92.5% and the acute and late
toxicity was minimal.
Conclusions: FAST-boost with a single fraction of HDR is a good, quick,simple technique when surgical margins are free. Local control and cosmetic
results at ten-year follow-up are good enough to consider it as a standard.
624 poster
PREOPERATIVE HYPOFRACTIONATED AND INTRALUMINAL
RADIOTHERAPY FOR BREAST CANCER TREATMENT
D. Sendiuliene1 , K. P. Valuckas1 , E. Aleknavicius1 , V. Atkocius1 , V.
Ostapenko1 , I. Kuzmickiene1
1
I NSTITUTE OF O NCOLOGY V ILNIUS U NIVERSITY, Vilnius, Lithuania
Purpose: The aim of this study was to evaluate the impact of hypofractionated preoperative radiotherapy including intraluminal Cf-252 neutron

PROSPECTIVE STUDY OF PARTIAL BREAST IRRADIATION USINGHIGH DOSE RATE INTERSTITIAL BRACHYTHERAPY: SEVEN-YEAR
OUTCOMES
H. Kader1 , W. Ansbacher2 , C. Popescu2 , M. Panadés3 , J. Pai1 , D. Nguyen1 ,P. Truong1
1
BC C ANCER AGENCY, VANCOUVER I SLAND C ENTRE, Radiation Oncology,
Victoria, Canada
2
BC C ANCER AGENCY, VANCOUVER I SLAND C ENTRE, Medical Physics,
Victoria, Canada
3
U NITED L INCOLNSHIRE H OSPITALS, Clinical Oncology, Lincoln, United
Kingdom
Purpose: To report toxicities, cosmetic outcomes and local control in a seriesof patients treated on a pilot study of partial breast irradiation (PBI), using CTplanned high-dose-rate (HDR) multi-catheter interstitial brachytherapy.
Materials: Between May 2003 and December 2005, 30 subjects with low-riskbreast cancer were treated with adjuvant PBI using multi-catheter interstitial
HDR brachytherapy. All subjects fulfilled the following criteria: age >50 years;
invasive ductal histology; T <3cm, pN0; ER positive; LVI negative; and surgical margin >0.2cm. Pre-implant CT was performed 4-8 weeks following
breast-conserving surgery. The PTV was the excision cavity + 1.5cm, excluding chest wall and 0.5 cm from skin. An ideal virtual implant was createdbased on the Paris System. Post-implant CT planning was performed, delivering 32.4Gy in 9 BID fractions over 5 days, using an Iridium-192 HDR
after-loading system. Acute toxicity (NCI criteria), late morbidity (RTOG)
and overall cosmesis (EORTC) were prospectively evaluated and recurrence
rates have been updated.
Results: Mean tumour size was 1.2cm (0.4 2.4cm). Acute toxicities at 6
weeks and 3 months were all grade 1: fatigue (7%, 0%); pain due to radiation(4%, 7%) and radiation dermatitis (7%, 0%). Telangiectasia was observed in
two subjects (7%), maximum dimension 3.5 and 2.0cm, 25 and 37 months
after treatment. Fat necrosis occurred in 3 subjects (10%), 13, 16 and 68
months after treatment, one undergoing mastectomy. Cosmesis was goodexcellent in 82% of patients at baseline; while 89% had stable or improved
cosmesis at three years compared to baseline. At a median follow-up of 80
months (range 60-90 months), patient and disease status were as follows:
32 months after diagnosis, one subject developed an ipsilateral breast nodepositive tumour in a different quadrant which was pathologically distinct fromthe original tumor; salvaged with mastectomy, axillary dissection and postoperative RT. Another subject developed nodal-only recurrence at 42 months,
salvaged with axillary dissection and post-operative RT. A third developed
lung and bone metastases 49 months after diagnosis and died 8 months later.
None of the subjects experienced recurrence in the same quadrant as theindex tumour.
Conclusions: In this cohort of women with favorable-risk breast cancer, PBI
with CT-planned interstitial HDR brachytherapy provided excellent local control, good-excellent cosmesis and acceptable acute and late toxicities.

S 255

626 poster
PULSED DOSE RATE BRACHYTHERAPY AS THE BOOST
AFTER EXTERNAL BEAM RADIATION THERAPY AND BREASTCONSERVING SURGERY OF T1–T2 BREAST CANCER
J. Skowronek1 , A. Chichel1 , M. Kanikowski1 , G. Zwierzchowski2 , W.
Burchardt1
1
G REATER P OLAND C ANCER C ENTRE, Brachytherapy Department, Poznan,
Poland2
G REAT P OLAND C ANCER C ENTRE, Medical Physics, Poznan, Poland
Purpose: Breast-conserving surgery (BCS) followed by radiotherapy (RT)
has become the standard treatment for the majority of patients with earlybreast cancer. Postoperative whole-breast irradiation is associated with highlocal tumor control rates. Patients remaining at high risk for local failure are
well defined and should be treated with an additional boost to the tumor bed
with proper safe margin, and adequate technique based on clinical and morphological factors. Most of this patients are treated with HDR technique but
PDR technique is also in area of interest. We present our clinical observations of irradiation of the tumor bed as a boost using Pulsed Dose Ratebrachytherapy (PDR-BT) after breast conservation therapy (BCT) in patientswith early-stage breast cancer.
Materials: Between July 2002 and October 2007, a total of 63 female patients with stage I to II breast cancer underwent BCT. This therapeutic procedure consist of a BCS, whole breast irradiation (WBRT), and a boost asadditional irradiation to the tumor bed using interstitial PDR-BT via flexible
implant tubes. Single, double and triple plan implant was used in 6, 44 and13 cases respectively. The boost dose was 10 Gy (1 Gy pulse hourly) inall patients and they were treated with a Nucletron-microSelectron HDR remote afterloading equipment using an Ir-192 isotope with initial activity of
370 GBq (10Ci). Two sets (pre-implant and post-implant) of CT scans wererequired to improve the implant quality. The treatment planning was basedon the CT guided 3-D reconstruction of the surgical clips, implant tubes andcritical structures localization (skin, ribs and lungs). We analyzed clinical outcome and cosmetic effect (RTOG/EORTC Late Radiation Morbidity Scoring
Schema) in comparison with chosen prognostic and dosimetric factors. We
analyzed also technical feasibility of this technique.
Results: Median follow-up was 66 months (36 96 months). After the followup local control was reported by all patients. Four different patients showedsigns of having distant disease (n=2, 3.2%) or axillar lymph node metastasis (n=2, 3.2%). These patients are still in the treatment. Late side effects
of grade 1 we noted in 6 cases (9.5%) and of grade 2 in 2 cases (3.2%).
Global cosmetic result, classified by radiooncologists, was excellent to fairin 50 cases (79.4%) of patients. From the patients view, 58/63 (92.1%) had
an excellent to fair cosmetic outcome. Due to short overall treatment time(shorter than 10 hours) we didn’t observe serious technical problems.
Conclusions: The interstitial PDR-brachytherapy is in patients with earlybreast cancer a meaningful treatment option with a high local control rate.
The advantages of PDR brachytherapy include: outpatient treatment, controlof patient positioning to assure accuracy of treatment delivery, ability to optimize dose distribution, improvement in radiation protection for staff, possibilityof shorten treatment time in compare to electron boost technique. It seems
that cosmetic effect of PDR-BT was satisfactory in the majority of patients.
627 poster
QUALITY INDEXES IN 3D-CT-BASED HIGH DOSE RATE BREAST
BRACHYTHERAPY WITH PLASTIC MULTI-CATHETERS
M. D. De las Peñas-Cabrera1 , L. Díaz Gómez1 , E. Gonzalez Calvo1 , V. Díaz
Díaz1 , E. Munive Alvarez1 , I. Villanego Beltran1 , E. Alonso Redondo1
1
H OSPITAL U NIVERSITARIO P UERTA DEL M AR, Department of Radiation
Oncology, Cadiz, Spain
Purpose: To evaluate quality indexes in 3D-CT-based HDR breast
brachytherapy and to compare between patients with accelerated partial
breast irradiation and those with boost after external whole breast radiotherapy.
Materials: This is a prospective study on 82 patients from March 2008 to
December 2010. In 14 cases (17.07%) patients received accelerated partial breast irradiation (APBI) and the remaining 68 (82.92%) had boost after
external radiation therapy. In total, age was 53.79 ± 11.67. Age was significantly lower in the boost group (50.46 ± 9.64 Vs. 69.43 ± 6.90; p =0.000000001). Tumor size was significantly bigger in the boost group (18.46± 10.07 Vs. 12.57 ± 7.99 mm; p = 0.04) while the margin was similar in bothgroups (6.54 ± 3.43 Vs. 7.32 ± 5.73 mm for the partial irradiation and boost
respectively; p = 0.63). Planning margin was established in 1 cm for boost
and 2 cm for APBI.Data are shown as mean ± SD. The Student’s t test wasused for comparisons.
Results: Patients were planned using 2 planes in 2 cases of APBI (14.3%)
and in 31 cases of boost (45.58%). In the rest 3 plannes were used. PTV, DHI
and VI-200 were significantly higher in patients receiving APBI than in thosewith boost (82.00 ± 46.00 Vs. 54.40 ± 27.96; p = 0.004 for PTV; 78.79 ±3.55 Vs. 76.04 ± 4.56; p = 0.03 for DHI; and 8.5 ± 3.8 Vs. 6.62 ± 2.31; p =0.01 for VI-200. The rest of the studied indexes were similar in both groups.

S 256B RACHYTHERAPY: G YNAECOLOGYB RACHYTHERAPY: B REAST C ANCER

PTV-90: 86.5 ± 13.25. VI-150: 21.79 ± 12.22. ΦV-200: 5.29 ± 2.5 mm.
COIN: 56.71 ± 10.27 for patients with APBI and PTV-90: 79.54 ± 86.50;
VI-150: 17.35 ± 6.99; ΦV-200: 4.46 ± 1.43; COIN: 52.68 ± 11.03 for theboost group. There were no significant correlations between tumor size andany of the studied quality indexes.
Conclusions: Quality indexes in 3D-CT based HDR were within the recommended ranges for patient planning, although COIN was in the lower limit
which should be improved. Quality indexes were better in the APBI group.
These differences are not related to a larger tumor size but probably to awider planning margin in patients with partial irradiation.
628 poster
SHORT-COURSE ACCELERATED PARTIAL BREAST IRRADIATION(OVER 2 DAYS) IS FEASIBLE WITH THE CONTURA® MULTI-LUMEN
BRACHYTHERAPY DEVICE
A. Khan1 , F. Vicini2 , R. Dale3 , B. Haffty1 , D. Todor4 , D. Moore1 , D. Arthur4
1
C ANCER I NSTITUTE OF N EW J ERSEY, New Brunswick, NJ, USA
2
W ILLIAM B EAUMONT H OSPITAL, Royal Oak MI, USA
3
C HARING C ROSS H OSPITAL /I MPERIAL C OLLEGE, London, United Kingdom
4
V IRGINIA C OMMONWEALTH U NIVERSITY, Richmond, VA, USA
Purpose: Accelerated partial breast irradiation (APBI) is now considered astandard of care adjuvant therapy for selected groups of women by several
specialty societies, including the American Society of Radiation Oncology(ASTRO). A typical course of APBI consists of 10 fractions delivered over
5 treatment days. Shorter courses of APBI with novel fractionation schedules
are now being actively investigated. A large randomized trial from Europe has
recently shown the safety and efficacy of a single-fraction adjuvant approach(with limited follow-up). We designed a prospective trial of hypofractioned,
balloon based APBI that circumvents the potential radiobiological and logistical shortcomings of currently available, single-fraction APBI approaches.
Materials: We designed a single-arm, multi-institutional, prospective phase
II trial that sequentially treats three cohorts of women (each n=30) with threeprogressively hypofractionated schedules. Eligible women are older than 50
with unifocal invasive or in situ tumors less than 3.1 cm, excised with negative
margins, and with negative lymph nodes and positive hormone-receptors. Using a reference schedule of 60 Gy delivered in 2 Gy fractions, and assuming
tumor parameters: = 4 Gy; = 0.27 Gy-1, and repopulation parameters of: effective doubling time Teff = 26 days; delay time = 0 days, the reference tumor
BED is 86 Gy4. For the APBI treatment, we assume the balloon is sphericalwith an average diameter of 4.5 cm. Dose is prescribed 1cm from the balloon
surface, i.e., the balloon radius is 2.25 cm and the prescription distance is
3.25 cm. Given these considerations, we began with a schedule of 4 fractions of 7 Gy delivered twice-daily. If specific predetermined criteria for stopping the study due to significant toxicity are not reached we plan to change
the fractionation to 8.25 Gy for 3 fractions and then to the final fractionation
schedule of 10.5 Gy for 2 fractions. Given the novelty of this approach, wechose to use the multilumen Contura MLB®(Bard, Irvine CA) device to afford
dosimetric flexibility beyond what could be expected of a single lumen device.
We defined very conservative dosimetric criteria for acceptability: maximum
skin and rib dose to not exceed 100% of prescription dose, and V150 and
V200 to not exceed 40 cc and 10 cc, respectively. Each dose cohort of 30
women will be followed for a minimum of 6 months before advancing to thenext dose cohort.
Results: A total of 14 patients have been enrolled at the 7 Gy x 4 fractions
dose-level. Dosimetric criteria have been achieved in all cases. In 13 patientswith available data, the range of skin spacing has been 7-25 mm (mean=12.5mm), and the range of rib spacing has been 3-52 mm (mean 18 mm). No
predefined toxicities have been observed, and no acute toxicity greater than
CTCAE grade 2 have been observed.
Conclusions: Short-course APBI is dosimetrically feasible using the ConturaMLB®. Our approach is based on well-defined radiobiological parameters
and allows for an abbreviated course of treatment that is guided by full pathological review and the ability to objectively achieve and validate acceptable
dosimetric criteria in each case.
629 poster
TUMOR BED LOCALIZATION IN CLOSED CAVITY AND ONCOPLASTIC SURGERY IN BREAST BRACHYTHERAPY. A VOLUMETRICBASED MODEL.
L. Díaz Gómez1 , M. D. De las Peñas-Cabrera1 , V. Díaz Díaz2 , E. Gonzalez
Calvo2 , E. Munive Alvarez2 , I. Villanego Beltran2 , L. Gutierrez Bayard2 , C.
Salas Buzon1 , E. Alonso Redondo2
1
H OSPITAL U NIVERSITARIO P UERTA DEL M AR, Department of Radiation
Oncology, Cadiz, Spain
2
H OSPITAL U NIVERSITARIO P UERTA DEL M AR, Cadiz, Spain
Purpose: Breast Brachytherapy after recent publications of several prospective clinical trials has become a useful alternative both APBI as boost after
EBRT. For the location of the tumor bed on both cases, they have been usedvarious methods of image, by joining all facilitate this work. In cases with open

cavity, intraoperative ultrasound has become the standard method for the localization of bed, but in cases with closed cavity and oncoplastic surgery as
occurs in our centre, where also patients going under adjuvant chemotherapy
if is indicated with the changes that this entails, one must use various techniques to be certain of making the implant with adequate quality. Our aim
with this study is to describe our method of localization of the tumor bed inour experience in breast brachytherapy in recent years.
Materials: From March 2008 until November 2010, 82 patients were selected
to perform breast brachytherapy in the 2 described ways. For the correct
location of the tumor bed, our procedure is divided into the following steps.
Step 1: In the case of boost, we design a PTV that would be similar to EBRTBoost, with 3D simulation. On the last day of EBRT, we calculate a 0 reference
beam without collimation that delimitates a volume with proper margins forthe previous PTV that defines the upper, lower and laterals surgical clips.
With this we get the volumetric accuracy of the area of lumpectomy. Step
2: The day before the completion of the implant, with the radiology service
collaboration, we made an ultrasound (US) where they indicated the surgicalarea or seroma if present, the distance of the upper limit to the skin to ensure
is equal or more than 5 mm, and the lower limit to the pectoral muscle.Step 3:
After US, is designed the implant and we choose the number of planes andtemplates to use that include the volumetric and ultrasound areas. With thispattern, is made a CT scan that verifies the correct placement in every axe of
space.
Results:
Conclusions: With this method, in cases of oncoplastic surgery+ close cavity
and adjuvant chemotherapy, we get a perfect localization of the tumor bed andwe have the certain that is made a quality implant satisfying the coverage
standard for the volume design.

Brachytherapy: Gynaecology
630 poster
3D IMAGE BASED TREATMENT PLANNING IN VAGINAL CANCER
BRACHYTHERAPY
H. B. Zobec Logar1 , R. Hudej2 , B. Segedin2 , P. Petric2

S 257

without disease (89,5 %), and 2 cases death for another cause (3,5 %). With
median follow-up of 16 months, the 2 years free disease survival was 90.2%
and 2 years overall survival was 88.3%. No toxicity was reported in the 52,6%of patients, and when it was present the most frequent was cystitis (12.3%).
Conclusions: The exclusive vaginal brachytherapy is effective in ensuring
vaginal control, with few toxic effects. So, this schedule should be an adyuvant treatment for patients with endometrial carcinoma with early stage.

1

I NSTITUTE OF O NCOLOGY “I.C HIRICU ŢĂ ”, Department of Brachytherapy,
Cluj-Napoca, Romania
2
I NSTITUTE OF O NCOLOGY L JUBLJANA, Department of Brachytherapy,
Ljubljana, Slovenia

Purpose: Vaginal cancer represents less than 1 % of all gynaecological malignancies and radiotherapy is the treatment of choice for most patients. We report on our first experience with MRI/CT assisted vaginal cancer
brachytherapy (BT).
Materials: Four patients with locally advanced squamous cell cancer ofvagina, treated at our institution between December 2008 and December
2009, were included in analysis. Two patients presented with FIGO stage
III, one with stage IVA and one with stage IVB (two small lung metastases)
tumor.Treatment consisted of pelvic 3D conformal external beam radiotherapy (45 to 50.4 Gy, 1.8 Gy per fraction) plus weekly cisplatin. Following
EBRT, MRI- (3 patients) and CT- (one patient) based PDR BT, using interstitital/intracavitary applicator, was performed. HR CTV and organs at risk
(OAR: bladder, rectum and urethra) were contured on post-insertion pelvic
MRI/CT, according to the adequately adapted GEC-ESTRO recommendations for cervix cancer BT. A nominal dose of 18.5-20 Gy in 21-25 hourly
pulses per insertion was prescribed to the HR-CTV. We aimed to achieve a
D90 for the HR CTV of > 85 Gy, while respecting our dose constraints for
the OAR. Total dose (external beam + BT) was calculated according to equivalent dose in 2 Gy fractions for HR CTV (α/β =10 Gy) and organs at risk
(α/β =3 Gy), using 1.5 h as the half time of sublethal damage repair. In stage
IVB patient, resection of lung metastases was performed after completion ofchemo-irradiation. DVH parameters for the target volumes (D90, D100 andV100) and OAR (D0.1cc for urethra, D2cc for bladder and rectum) were reported. Complete remission rate and acute toxicity were assessed.
Results: Mean D90 for the HR CTV was 87 Gy (st. dev. 12 Gy). OAR dose
constraints were respected in all cases with D2cc for bladder and rectum at
63 Gy (st. dev. 6 Gy) and 64 Gy (st. dev. 5 Gy), respectively. Urethral D0.1cc
was 86 Gy (st. dev. 15 Gy). Complete tumor remission was achieved in all
patients. Self limited acute toxicity (no grade 3 or 4) resolved within 3 weeks.
After a short follow up, all patients are alive with no evidence of disease orgrade 3-4 late side effects.
Conclusions: GEC ESTRO recommendations for MRI based cervix cancer
BT can be applied, with some modifications, for treatment of vaginal tumors.
Systematic adaptation of concepts and terms, defined in the recommendations, may be warranted for this tumor site. 3D optimization of dose distribution is reflected in favourable DVH parameters and encouraging treatment
outcome. Larger patient number and longer follow up are needed to assess
the clinical impact of the described approach.
631 poster
ADYUVANT VAGINAL BRACHYTHERAPY WITHOUT PELVIC EXTERNAL BEAM RADIOTHERAPY FOR ENDOMETRIAL CANCER
M. D. P. Vargas Arrabal1 , I. Tovar Martin1 , R. Del Moral1 , N. RodriguezIbarria2 , M. Gentil Jiménez1 , M. Zurita Herrera1 , T. Guerrero1 , M. Martinez
Carrillo1 , M. Navarro González3
1
H OSPITAL U NIVERSITARIO V IRGEN DE LAS N IEVES, Radiation Oncology,
Granada, Spain
2
H OSPITAL RUIZ DE A LDA, Radiation Oncology, Granada, Spain
3
H OSPITAL U NIVERSITARIO V IRGEN DE LAS N IEVES, Radiation Oncology,
Granada, Spain
Purpose: The aim of this study is to report the results obtained in patientsdiagnosed of endometrial carcinoma stage IA-IIA treated with radical hysterectomy, bilateral salpingo-oophorectomy, peritoneal washing citology andlymph node dissection followed by adyuvant brachytherapy at our institution.
Materials: From 2006 until 2009, 57 patients with endometrial carcinoma
stage IA-IIA have been treated with surgery and exclusive vaginal brachytherapy. Median age of the series was 62 years. Total hysterectomy, double anexectomy, pelvic lymphadenectomy and peritoneal washing was made in 61,4
% of the patients. The other 38,6 % were treated with abdominal hysterectomy, double anexectomy alone and random node sampling. The majority ofthe pathologycal FIGO stages were IB (77,2 %), and histological degree wereII (52,6 %). Exclusive brachytherapy was performed using vaginal cylinders
with 3 cm of diameter (50,9 % of patients). The reference isodosis covering
the proximal 3 cm of the vagina (96,4 % of cases). The dose was specified at
5 mm distant from the surface of the cylinder. Dose schedule with high dose
rate brachytherapy was 21 Gy in 3 fractions of 7 Gy (over a period of three
weeks). The median of dose equivalent received in the rectum was 31,8 Gy
and in bladder 38 Gy.
Results: At the moment of this analysis there are 4 relapses (7.2 %): 2 ofthem live with disease (3,5 %), and 2 death for tumor (3,5 %); 51 cases live

632 poster
APPLICATOR DISPLACEMENTS DUE TO ADDITIONAL SCAN FOR
3D IMAGE GUIDED BRACHYTHERAPY FOR CERVICAL CANCER
Y. Kim1 , Y. Huang1 , D. Chesnut1 , N. Sangster1 , A. Oldham1
1
U NIVERSITY OF I OWA, Radiation Oncology, Iowa City, USA
Purpose: To present an applicator localization system and quantify thedisplacement of an applicator due to a patient’s movement between abrachytherapy (BT) room and CT /MR scan room.
Materials: A titanium Fletcher Suit Delclos style tandem and ovoids (T&O)(Varian) was used for high dose rate BT. To minimize T&O displacements, a
localization system has been developed. Orthogonal radiographs were taken
before and after MRI scan (pre- and post-X-ray). Six T&O implants wererandomly selected. Active tandem lengths ranged 5 ~9 cm. Tandem angles
were 30 and 45 degrees. Ovoid diameter was 1.6 cm for all cases. Two
T&O reconstructions were retrospectively performed on pre- and post-X-ray.
The measurements of vector distances (d) were performed between eachdwell position of T&O and a reference point (i.e. the center of bladder foley).
The differences of d (d) were used to quantify T&O displacements. A radioopaque gauze was used for vagina packing. A high resolution (3 Tesla) MR
scanner located at radiation oncology department was used. T&O procedure
was performed under full anesthesia.
Results: A T&O localization system consists of a HDR-board (Figure panel
A, B, C) and a T&O support device (Figure panel D). A HDR-board can be
split into two pieces so that a patient lays down on it at the beginning, gets
implanted by splitting its inferior part, gets transferred to MR scan with theboard, and receives treatment on the board in HDR room. At early learningcurve periods, we found considerable T&O displacement could be happened
mainly when a patient was transferred between HDR-table to a transfer-table/ a transfer-table to MR-table. A T&O support device with MR-compatible titanium localized T&O against a patient body. Utilizing the localization system,
T&O displacements due to MRI scan was determined as on average d = 1.6± 0.6 mm. The values of d were on average 1.3 ± 0.6 mm for tandem andon average 2.2 ± 1.7 mm for ovoids. However, the cases showing ≥ 5mm
displacements were clinically observed with very low frequency (e.g. ≤ 5%).
An applicator displacement is recommended to be carefully monitored whena patient is moved to different rooms for MRI or CT, especially without an applicator localization system. The studies for a robust localization system are
expected to be followed as 3-D image-guided BT is widely practiced in clinics.

S 258B RACHYTHERAPY: G YNAECOLOGYB RACHYTHERAPY: G YNAECOLOGY
a local control rate of 90%. The toxicities relating to this technique are minimal and our published results reveal a 14% Grade 1, <3% Grade 2 Rectal
toxicity and 6% Grade 1, <2% Grade 2 Bladder toxicity. These results arecomparable with published data from other centres employing image-basedbrachytherapy
Conclusions: Accessible imaging modalities, such as ultrasound, allow departments with limited resources to deliver highly conformal and adaptive
brachytherapy in a safe and timely manner that does not compromise outcomes.
634 poster
CT IMAGE BASED DOSIMETRIC EVALUATION OF GYN GEC-ESTRO
DVH PARAMETERS FOR HDR BRACHYTHERAPY IN CERVICALCANCERS
V. Jagtap1 , A. Mawlong1 , U. Mahantshetty2 , S. Jamema3 , R. Engineer1 , S.
Chopra1 , D. Deshpande3 , S. K. Shrivastava1
1
TATA M EMORIAL H OSPITAL, Department of Radiation Oncology, Mumbai,
India
2
TATA M EMORIAL H OSPITAL, Mumbai, India
3
TATA M EMORIAL H OSPITAL, Department of Medical Physics, Mumbai, India

Conclusions: Applicator displacements were determined on average 1.6 ±0.6 mm when an applicator localization system was utilized. To minimize
overall uncertainties in 3-D image-guided BT procedures, a localization system for an applicator seems to be beneficial.
633 poster
BRACHYTHERAPY IN REAL-TIME AND REAL-LIFE: ADAPTIVE AND
CONFORMAL, IS IT POSSIBLE?
P. Khaw1 , S. Van Dyk1 , M. Garth1 , D. Bernshaw1 , K. Narayan1
1
P ETER M AC C ALLUM C ANCER C ENTRE, Division of Radiation Oncology
and Cancer Imaging, East Melbourne, Australia
Purpose: To describe an image-based brachytherapy program that provides
adaptive and conformal planning in a situation where access to MRI is limited.
Materials: This program has evolved due to limited available resources andinfrastructure, in particular the need to maintain a high patient throughput,despite limited access to both the HDR unit, housed in the Operating Suite,and MRI. The resulting program routinely uses ultrasound guidance for applicator insertion, placement verification and conformal planning. Brachytherapy planning is based on a rigid, locked applicator system, (Nucletron MRI
compatible Standard CT/MRI applicators). A single MRI and sequential ultrasound images at each insertion facilitate real-time, forward planning for every
patient.Information on all patients treated with this system since its inception
has been collected in a prospective database, allowing us to assess both ourtumour control and toxicity outcomes.
Results: Our centre routinely treats up to 3 patients per session (4 hours= 1 session), with 2 sessions per week being available for Gynae-Oncology
Brachytherapy, averaging 50-60 patients per annum. The routine use of ultrasound with each insertion means we are able to:1. Verify position of the tandem and ovoids at each insertion, resulting in a controlled insertion with little
risk of uterine perforation.2. Verify position of bladder and rectum in relation
to the tandem and ovoids.3. Adapt our treatment plan according to the geometry we achieve with each insertion to ensure that we maintain target volume
coverage and minimize, where possible, increased dose to Organs at Risk.4.
Ensure that once the tandem and ovoids are inserted and verified, there is noor minimal movement between insertion and treatment delivery.Each patient
has access to 1 MRI per course of treatment, which is used to contour the
GTV and organs at risk, and confirm that the plan has adequate coverage ofthe target volume. Our group has already published disease control and toxicity outcomes using this technique. With this method, we are able to achieve

Purpose: In cervical brachytherapy, ICRU 38 based rectal and bladder point
doses are reported on orthogonal X-ray based planning. In past decade,imaging modalities like CT, MR, PET have been incorporated in externaland brachytherapy planning. GYN GEC ESTRO Working Group has recommended contouring guidelines, concepts and terms in 3D Image Based
Treatment Planning with the use of MRI. With wide and easy availabilityof CT Scanners, its use in external radiation planning is standardized. Inbrachytherapy planning, it has its own limitations. To evaluate CT Imaging forcontouring and documentation of DVH parameters for rectum, bladder andsigmoid we undertook this dosimetric study.
Materials: In this dosimetric study, cervical cancer patients undergoingradical radiation therapy and Ring-tandem HDR Intracavitary Brachytherapy(ICBT) were included. The CT data sets were retrieved and OAR’s namely
bladder, rectum and sigmoid were contoured on planning CT scan. Outerwalls of the organs were contoured as OAR volumes. Bladder was contoured
from bladder neck including the foley’s bulb upwards. Rectum contoured fromanal canal upto recto-sigmoid and sigmoid upto fundus. CT based planningwas done with standard loading patterns with dose prescription of 7 Gy topoint A. Manual optimization to reduce doses to OAR’s was allowed. ICRU
rectal and bladder point doses, doses received by 0.1cc, 1cc and 2cc OAR
volumes were documented. ICRU point doses were compared to rectal andbladder 2cc doses.
Results: A total of 28 patients ( 1 applications each) were evaluated. The
results for prescription of 7 Gy to point A were calculated. The mean (±SD)
dose for ICRU bladder and rectal points were 5.4Gy(±2.7) & 5.5Gy(±1.8)respectively. With CT image based planning 0.1cc, 1cc and 2cc doses
were 10.5(±5.6), 8.4(±3.2), 7.3(±2.4) for bladder, 7.2(±2.8), 5.7(±1.8),
4.9(±1.4) for rectum and 8.1(±4.4), 5.7(±2.2), 5.09(±1.8) for sigmoid respectively. On comparison, mean 2cc bladder doses were significantly higher(p = 0.003) than mean ICRU bladder point [mean 7.3(±2.4) Vs 5.4(±2.7)].
However, mean 2cc Rectal dose was not significant (p = 0.10). In spite ofmanual optimization mean 2cc doses of sigmoid are high compared to rectal
2cc doses.
Conclusions: CT Based contouring of rectum, bladder and sigmoid is feasible. The Bladder 2cc doses are significantly higher than ICRU point. 2cc
Rectal doses correlate well with ICRU Rectal point. In our series sigmoid
contouring and dose compilation was possible only on CT imaging. Clinicalrelevance and implications of high sigmoid doses needs to be establishedfurther.
635 poster
DAILY MRI IMAGING IN PULSED DOSE RATE BRACHYTHERAPYFOR LOCALLY ADVANCED CERVICAL CANCER
M. Morgia1 , L. Walsh1 , J. Xie2 , J. Jezioranski2 , J. Yan1 , Y. B. Cho2 , A.
Fyles1 , M. Milosevic1
1
P RINCESS M ARGARET H OSPITAL, Department of Radiation Oncology,
Toronto, Canada
2
P RINCESS M ARGARET H OSPITAL, Department of Radiation Oncology andMedical Physics, Toronto, Canada
Purpose: Increasingly MRI-based volumetric planning is being incorporated
into delivery of brachytherapy, allowing for optimisation of target coverageand sparing of organs at risk (OAR). Critical to this is the accurate delineationof these volumes given the steep dose gradients achieved in brachytherapy.
Daily MRI imaging during pulsed dose rate brachytherapy (PDR BT) was used
to evaluate the changes in high risk CTV (HR CTV) and OAR volumes andchanges in dosimetry.
Materials: 50 patients undergoing definitive chemoradiotherapy for locallyadvanced cervical cancer between October 2008 and September 2010 were
prospectively enrolled on an MRI-guided PDR brachytherapy protocol. An

MRI was done after insertion of a customised intrauterine single line source,
followed by an MRI on Day 2 and Day 3. The HR CTV and OARs were
contoured by a radiologist and reviewed by the treating radiation oncologist.
A brachytherapy plan was optimised along the GEC ESTRO guidelines. Day
2 and Day 3 MRIs were compared to the Day 1 images and plan with regards
to volumetric and dosimetric differences, with adequate dosimetry defined as
HR CTV D90 ≥ 87Gy (EQD2).
Results: 50 patients had volumetric and dosimetric data available for Day 1,
39 and 23 patients had MRIs on Day 2 and 3, respectively. The mean HR CTV
on the Day 1 MRI was 30.4cm (range 10.6cm - 74.6cm). HR CTV increased
during treatment (mean 33.6 cm on Day 2 and 35.4cm on Day 3, p=0.0001),
with an average increase of 15%. Mean Day 1 rectal volume was 54.6 cm
with a mean increase in volume on Day 2 to 67.6cm (p=0.002).Adequate
dosimetry was achieved in 92%, 66% and 50% of cases on Day 1, Day 2 andDay 3, respectively with a mean D90 on Day 1, 2, and 3 of 96.1Gy, 89.3Gy
and 87.5Gy (p<0.0001). The mean Day 2 and Day 3 D90 of patients notachieving the GEC-ESTRO-defined D90 were 80Gy (range: 57.6 86.5Gy)
and 81Gy (range 59.3 86.4Gy). It was observed that all patients with poor
Day 1 dosimetry had subsequent poor dosimetry. 42% of those with poor
dosimetry on any day had poor average dosimetry (mean D90 86.7Gy).There
was no significant variation in bladder dosimetry over time. The mean Day
1 rectal 2cc dose was 69.9Gy. There was a mean difference of 4.2% and4.5% on Day 2 on Day 3, with a significant increasing trend in dose over time
(p=0.04).
Conclusions: Reassuringly, the overall D90 over a 3 day period of PDR BT
for 91% of patients met the GEC ESTRO criteria. This was despite a significant trend of D90 dosimetry decreasing over time and significant changes in
HR CTV and rectal volumes on daily MRI imaging.
636 poster
DOSIMETRIC INTERACTION BETWEEN LYMPH NODE IRRADIATION AND MR BASED BRACHYTHERAPY FOR ADVANCEDCERVICAL CANCER
J. Van de Kamer1 , A. de Leeuw2 , M. Schippers2 , C. Nomden2 , I. M.
Jürgenliemk-Schulz2
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands
2
U.M.C. U TRECHT, Radiation Oncology, Utrecht, Netherlands
Purpose: To investigate the dose contribution of external beam radiotherapy(EBRT) lymph node irradiation to the high-risk clinical target volume (HRCTV) in combined EBRT and brachytherapy treatment (BT) of cervical cancer.
Additionally, the BT dose to the pathological lymph nodes (LN) was assessed.
Materials: From our clinical database, we selected five patients who underwent lymph node irradiation as part of their treatment. All patients received
25*1.8Gy EBRT, given with IMRT combined with a PDR BT boost on the HRCTV, in 2 fractions of 32x60cGy. An EBRT boost of 5 or 7*2 Gy was given to
the LN, using an APPA or a combination of APPA and 4 field technique. The
nodes were located at the iliac region. For brachytherapy, the HR-CTV andorgans at risk were contoured on T2 weighted MR datasets, in accordancewith the GEC-ESTRO guidelines. Additionally we contoured the visible nodes
on these data sets, in total 16. The volumes of the HR-CTV were 15.9, 19.5,
29.3, 32.7 and 91.3 cm3 . We generated a standard plan and an optimised
plan, using additional interstitial needles for optimisation. We aimed for D90
HR-CTV of 84 Gy EQD2.With homemade software tools, we computed thebiologically weighted 3D EQD2 dose distributions of the complete treatment,
i.e. a summation of the elective EBRT, the EBRT boost, and the 2 BT dose
distributions. For biological modelling we used a half-time of repair of 1.5 hand α/β =10 Gy (HR-CTV and LN) and 3.0 Gy (other tissues). For this study,
we calculated both the contribution of the lymph node irradiation to the D90of the HR-CTV, and the contribution of the BT dose to the lymph nodes.
Results: The contribution of the EBRT LN boost to the D90 HR-CTV was <=1.0 Gy EQD2 for 8/10 plans (4 patients); for one patient it was 2.8 and 1.6 Gy
EQD2 for standard and optimised plan respectively. Compared to an aimed
dose of 84 Gy EQD2 this contribution is of minor importance.On the other
hand, the contribution of the BT dose distributions to D90 of the lymph nodes
varied between 3.1 and 12.0 (on average 6.0) Gy EQD2, highly dependanton the location of the node. An iliaca externa node received the highest dose.
Clinically, these dose values can be used to fine-tune the dose for the EBRT
LN boost.
Conclusions: For these 5 patients, the effect of the EBRT LN boost on D90
HR-CTV is negligible; the contribution of the BT dose distribution on the ilac
nodes can be considerable, depending on their location. Therefore, the BT
dose distribution should be taken into account when irradiating these lymph
nodes.

S 259

637 poster
DOSIMETRY OF SINGLE, MULTI-CHANNEL INTRACAVITARY
AND INTERSTITIAL HDR BRACHYTHERAPY USING 3D INVERSE
PLANNING.
C. Dempsey1 , C. Lapuz1 , P. O’Brien1 , A. Capp1
1

C ALVARY M ATER N EWCASTLE H OSPITAL, Department of Radiation
Oncology, Newcastle, Australia
Purpose: These days, there are an ever-increasing number of treatment applicators available for high dose rate (HDR) brachytherapy. Coupled with thefact that HDR brachytherapy now incorporates 3D planning and inverse dosevolume optimisation, it is valuable to understand the dosimetric limitations andadvantages of each applicator type. This study compared single and multichannel intracavitary applicators, along with a standard interstitial treatment
configuration for treatment of primary vaginal cancer and vaginal recurrencesof gynaecological cancers.
Materials: Several patients who have been treated for vaginal cancer witha multi-channel intracavitary applicator (Nucletron Miami applicator) werere-planned using a single channel approach and also an ’ideal’ interstitial
treatment arrangement. All plans were produced using the inverse planning
through simulated annealing (IPSA) module of Nucletron Oncentra MasterPlan planning software (version 3.2). The same planning target volume (PTV)
was used for all 3 applicator types, as were the bladder and rectal contours.
The same inverse-planning objective and constraint criteria were also applied
for all plans. Dose-volume histograms (DVHs) were then analysed for theirconformance to the ideal treatment dose.
Results: The conformance of the IPSA plan for each treatment type is highly
dependent on the size and symmetry of the PTV itself. Results indicate that
there is a critical depth (from the vaginal wall) of the PTV surface, beyond
which intracavitary applicators generate unacceptable mucosal dose. Interstitial treatments benefit from greater mucosal and rectal sparing, however
the IPSA module struggles to provide adequate coverage to any PTV lying
superior to the needle tips. Interstitial treatments also have a minimum PTV
surface depth, with the IPSA module unable to generate acceptable plansat depths shallower than this. This critical depth appears to lie between 7
mm and 10 mm, with PTV depths below 7mm conforming best with a single
or multi-channel intracavitary treatment approach and PTV depths beyond
10mm requiring interstitial treatment applications.
Conclusions: The depth and symmetry of the vaginal treatment PTV is the
crucial element in determining the appropriate brachytherapy treatment type.
A PTV surface depth between 7 mm and 10mm requires special consideration of mucosal sparing, dose coverage superiorly and rectal tolerance aswell as departmental factors such as theatre and staff availability. Patient
general well-being and tolerance to surgery must also be considered in suchcircumstances.
638 poster

ENDOMETRIOID CANCER AT “PROF.DR.ION CHIRICUTA” CANCERINSTITUTE, THE ROLE OF ADJUVANT RADIOTHERAPY
C. Ordeanu1 , R. Stahiescu2 , O. Coza2 , N. Todor3 , A. Irimie4 , A. Traila5 , M.
Muresan4 , S. Hica5 , A. Rancea4 , V. Nagy2
1"I.C HIRICUTA " C ANCER I NSTITUTE, Brachytherapy, Cluj-Napoca, Romania
2
U NIVERSITY OF M EDICINE AND P HARMACY C LUJ -N APOCA, Radiation
Oncology, Cluj-Napoca, Romania
3"I.C HIRICUTA " C ANCER I NSTITUTE, Medical Informatics, Cluj-Napoca,
Romania
4
U NIVERSITY OF M EDICINE AND P HARMACY C LUJ -N APOCA, Surgery,Cluj-Napoca, Romania
5"I.C HIRICUTA " C ANCER I NSTITUTE, Surgery, Cluj-Napoca, Romania
Purpose: The most common malignancy of the female genital tract is represented by endometrial cancer and it is usually managed through surgery;for patients who have a high risk of recurrence the radiotherapy necessary ingeneral is the adjuvant one. This study had the aim of assessing the efficacy
of adjuvant RT following surgery in endometrial cancer with endometrioid histology.
Materials: 389 patients with endometrial cancer were treated at the Oncology Institute "Ion Chiricuta" between January 2001 and December 2004; 277(71.21%) patients presented stage I , 74 (19.02%) - II , 34 (8.74%) - III, and
4 (1,03%) stage IV respectively. 96 (34.6%) patients, 51 (68.9%), and 21(61.7%) of patients with stage I, II and III respectively, were treated using
adjuvant RT. Depending on their age the patients were distributed into thefollowing age groups: 50-59, 60-69, respectively ≥ 70 years of age.
Results: The median follow-up was 87.95 months. The overall survival wasof 97%, 91% and 80% respectively for the low, intermediate and high-risk
group factor (p<0.01). We noticed that patients with endometrial cancer presnted different risks of local recurrence correlated with the presence of risk
factors including stage, grade, lymphovascular space invasion and age. The
locoregional recurrence was developed by 46.67% patients from the high risk
group including stage 1C and grade G3, IIA-G3 and IIB, without adjuvant radiotherapy, vs.12.28% who were treated by employing adjuvant RT (p<0,01).
17.31% patients with lymphovascular space invasion developed locoregionalS 260B RACHYTHERAPY: G YNAECOLOGYB RACHYTHERAPY: G YNAECOLOGY

recurrence vs. 7.42% respectively (p=0.04); 15 (9.26%), 13 (10.48%) and
12 (24.49%), patients age 50-59, 60-69, respectively ≥ 70 presented locoregional recurrence (p<0.01).
Conclusions: Adjuvant RT for patients with endometrial cancer had an important effect in reducing locoregional recurrences for patients with stage I
and II with high risk group factors
639 poster
EVALUATION OF UTILITY OF 3D INVERSE PLANNING SIMULATEDANNEALING (IPSA) IN THE TREATMENT OF UTERINE CERVIXWITH HDR BRACHYTHERAPY USING TANDEM AND RING APPLICATOR.
N. Bhandare1 , J. Clarke2
1
U NIVERSITY OF F LORIDA, Radiation Oncology, Gainesville, FL, USA
2
N UCLETRON C ORPORATION, Columbia, MD, USA
Purpose: To compare the utilization of 3D inverse treatment planning simulated annealing (IPSA) using dose objectives and weighting factors for dose
optimization with dose prescription to D90 of HRCTV with traditional method(Manchester system) of dose prescription to point A.
Materials: CT-MR fused image sets of 6 patients obtained for each of 5 fractions of HDR brachytherapy using tandem and ring applicator, were used
to generate 2 sets of treatment plans. The dose was prescribed to point
A in the 1st set of plans with use of standard dwell weight pattern, and to
D90 of HRCTV in the 2nd with plan optimization using IPSA.For each image
set, target volumes (GTV, HRCTV, IRCTV) and OARs (Bladder, Rectum, Sigmoid) were delineated. Per fraction prescription dose (6 Gy) and the limiting
doses to bladder (4.6 Gy), rectum and sigmoid (4.2Gy) were determined using EQD2 formulation accounting for dose delivered by external beam (Total
D90 for HR-CTV of 85 Gy, limiting EQD2 for bladder of 80 Gy, and that for rectum and sigmoid of 75 Gy). HRCTV, uterus, vaginal volume and OARs wereused for optimization. In accordance with GEC-ESTRO recommendations following parameters were obtained for target volumes: GTV-V, HR-CTV-V, IRCTV-V, GTV-D100, GTV-V100, HRCTV-D90, HRCTV-D100, HRCTV-V100,
HRCTV-V150, HRCTV-V200, IRCTV-D100, IRCTV-V100 and dose received
by 0.1, 1.0, 2.0 and 5.0 cc of each bladder rectum and sigmoid.
Results: The ratio of GTV-D100/ prescription dose varied between 0.80-1.5
for 1st set of plans and between 1.1-1.35 for 2nd set. HRCTV-V for 3 patients was <25cc (largest tumor radius < 2.0 cm) and >25 cc (largest tumor
radius ≥2 cm) for others. For 1st set of plans, when HRCTV-V < 25 cc theratio of doses HRCTV-D90/ dose to point A, varied between 1.15 to 1.50,
when HRCTV-V>25 cc, it varied between 0.75 to 0.95 . In 2nd set of plans,
HRCTV-D90 always received prescription dose. For the 1st set of plans theratio HRCTV-D100/ HRCTV-D90 varied between 0.56-0.74 and for the 2nd
between 0.45-0.75. For the 1st set of plans the ratio HRCTV-V150/ HRCTVV100 varied between 0.68-0.80 and for the 2nd between 0.50-0.70. The ratio
IRCTV-D100/prescription dose varied between 0.5-0.95 for 1st set of plans
and 0.5-0.75 for the 2nd . Doses to 2 cc of one or more OARs exceeded thelimiting doses in 4 patients 1st set of plans but remained less than or close tolimiting dose in all patients in 2nd set of plans. A 20-50 % reduction of doseto 2 cc of bladder, 15-35% to 2 cc of rectum/sigmoid were obtained in 2nd setof plans.
Conclusions: Though time consuming, optimization of treatment plan using IPSA yields a desired dose to HRCTV-D90 while holding the doses to
OARs close to it’s limiting value for the tumor volumes considered in thisstudy and offers a significant benefit in treatment of patients using image
based brachytherapy over traditional method.
640 poster
EXTERNAL BEAM RADIOTHERAPY PLUS VAGINAL BOOST WITH
LDR-BRT IN ENDOMETRIAL CANCER: STANDARD OR OVERTREATMENT?
D. Smaniotto1 , F. De Rose1 , C. G. Rinaldi1 , G. R. D’Agostino1 , B. Diletto1 ,L. Tagliaferri1 , G. Scambia2 , S. Luzi1 , N. Cellini1
1
C ATHOLIC U NIVERSITY OF S ACRED H EART, Department of Bioimaging
and Radiologic Science, Radiotherapy Institute, Rome, Italy
2
C ATHOLIC U NIVERSITY OF S ACRED H EART, Department of Gynaecology
and Obstetrics, Rome, Italy
Purpose: The aim of this retrospective analysis was to evaluate the morbidity
and effectiveness of radiotherapy (pelvic ERT and vaginal boost BRT-LDR) in
terms of local control (LC), disease free survival (DFS) and, overall survival(OS) in women with endometrial cancer treated with surgery followed by RT
and vaginal boost BRT-LDR.
Materials: Between 2000 and 2008, 201 patientswith endometrial cancer
after radical hysterectomy +/- pelvic and/or lombo-aortic lymphadenectomy
were submitted to adjuvant radiotherapy (45 Gy, 1.8 Gy/day on the wholepelvis) and subsequential vaginal boost (25 Gy to 0.5 cm from surface of theapplicator with LDR-BRT). Late toxicity was recorded according to EORTCRTOG scale.
Results: A total of 201 patients who received postoperative radiotherapy (RT)between 2000 and 2008 were evaluated, retrospectively. The mean age was
63 years (32-83), of them 68% were ≥ 60 years. Stage and grading distribution were as follows: 111 patients (55%) FIGO stage I, 54 patients (27%)
FIGO stage II, and 36 patients (18%) FIGO stage III; 24 patients (12%) G1;
120 patients G2 ( 60%), 57 patients (28%) G3. One hundred and twenty(60%) of the patients had a histological grade 2 tumour, while 57 (28%) and24 (12%) had a histological grade 3 or grade 1 tumour, respectively. The median follow-up was 62 months (range 4-115 ). OS and LC at 5 years were
93.8% and 94.8%, respectively. The disease free survival (DFS) at 5 years
was 85,4%. The stage, according to FIGO classification, resulted to be anegative prognostic factor far survival: survival rate was 96% in stage I, 88%
in stage II (IIA, IIB), 77% in stage III disease. Differences, even if not statistically significant, have also been found In terms of local control (98.1% instage I vs 92.4% in stage II, and 88.2% in stage III); the incidence of distantmetastases was 9% in stage I, 19% in stage II and 22% in stage III. The
age of patients seemed also to have a significant impact on prognosis : patients aged over 60 years had in fact a worse outcome, both in terms of 5
years survival (88.8% vs 100%) and incidence of distant metastases (25% vs
3%, p=0.01). Even histology, as expected, proved to influence the outcome:5-year OS was in fact 94% among endometrioid adenocarcinoma patients,
vs 87.6% of the special histotypes, while the incidence of relapse was 3.5%
vs 19% (p=0.024). A global 19% of late toxicity (EORTC-RTOG scale) wasrecorded. In particular 7.25% of the patients developed vaginal stenosis, ofthem more than 75% were > 60 years; 6% presented fund vaginal fibrosis;
other toxicity events such as proctitis, urinary incontinence and haemorrhoids
were shown in 7.35% cases.
Conclusions: Our results suggest that adjuvant ERT and BRT are associated with a better local control and improve survival in certain subgroups;
furthermore, these treatments are a well tolerated and effective therapeutic
option.
641 poster
EXTERNAL BEAM RT AND BRACHYTHERAPY AS ADJUVANTTREATMENTS OF ENDOMETRIAL CANCER: A SINGLE INSTITUTION’S SERIES.
G. Gambaro1 , L. Masini1 , L. Deantonio1 , S. Tunesi2 , C. Pisani1 , C.
Magnani2 , M. Krengli1
1

U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Radiotherapy, Novara,
Italy
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Epidemiology andBiostatistics, Novara, Italy2

Purpose: The purpose of this study was to retrospectively analyze a series ofendometrial cancer treated by adjuvant radiotherapy including external beam
radiation (EBRT) and brachytherapy (BRT).
Materials: From January 1995 to December 2006, a total of 224 patients with
Stage Ia-IIIc endometrial cancer were treated by adjuvant EBRT associatedwith intra-cavitary BRT in case of invasion of the cervical canal. Median age
was 66 years (range 41-83 years). All patients underwent surgery with pelvic
washing. Pelvic/paraaortic lymph node sampling was obtained in 107 patients(47.8%). Pathological stage according to the FIGO classification was as follows: 1 Ia, 51Ib, 87 Ic, 20 IIa, 23 IIb, 23 IIIa, 2 IIIb,17 IIIc. Miometrial invasion >50% was detected in 146 cases (65.1%) and positive washing in 12/224 (5%).
Histology was adenocarcinoma in 201 cases, mullerian carcinoma in 2, clear
cell carcinoma in 4, adeno-squamous carcinoma in 8, papillary serous carcinoma in 3, mixed cell type carcinoma in 3 and undifferentiated carcinoma in
3. All patients underwent EBRT to the pelvic region to a total dose of 45 Gy
in 5 weeks with daily fractions of 1.8 Gy, with a "four-field box" 3D-conformal
technique with 15 MV X-rays. After EBRT, 47 patients (21%) underwent intracavitary BRT boost with LDR 137 Cs sources inserted with a customized vaginal moulde (moulage). The median LDR dose, prescribed 0.5 cm from thevaginal surface, was 13 Gy (range, 10 -15 Gy). Acute and late effects wereassessed by the RTOG scoring systems.
Results: Follow-up ranged from 4 to 193 months (median 61 months) and
212/224 patients were assessable for tumour response. The global vaginal/pelvic control rate was 92% (195/212). After a median 10 months followup, loco-regional recurrence occurred in 8% of patients (17/212): 4.7% vaginal (10/212) and 3.3% pelvic (7/212). Vaginal relapse occurred in only 1.4%
(3/212) of cases in BRT group and in 3.3% (7/212) of patients who had notreceived BRT. Distant metastasis were observed in 7.5% patients (16/212)
with a median follow-up time of 60 months. At the last follow up, 179 patient
are alive free of disease (84.4%). Twenty patients died after progression disease (9.4%) and 13 died for other causes (6.1%). Thirty five patients developed G1 vulvar toxicity (15.6%), 21 in the group of patients treated by EBRT
and 14 in the group of patients treated by EBRT and BRT, 84 G1-G2 enteric
toxicity (37.5%), 64 in the group of patients treated by EBRT and 20 in thegroup of patients treated by EBRT and BRT; and 33 G1-G2 urinary toxicity(14.7%) 19 in the group of patients treated by EBRT and 14 in the group ofpatients treated by EBRT and BRT. Only two patients treated by EBRT and
BRT (0.9%) experienced late urinary toxicity.
Conclusions: Adjuvant RT including BRT in case of cervical invasion canoffer an high local control rate (92%), with modest acute and late toxicity. Our
results are supported by other similar literature data.

642 poster
FEASIBILITY OF USING CT-MR FUSION FOR HR-CTV CONTOURING IN IMAGE-GUIDED BRACHYTHERAPY FOR CERVIX CANCER
L. Tan1 , R. Jena2
1
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Oncology
Department, Cambridge, United Kingdom
2
A DDENBROOKE ’ S H OSPITAL, Cambridge, United Kingdom
Purpose: This is a retrospective dosimetric study to investigate the feasibilityof using CT-MR fusion for HR-CTV contouring in image-guided brachytherapy(IGBT) for cervix cancer.
Materials: The study group comprised 8 patients with locally advanced cervical cancer treated with radical chemo-radiation. The FIGO stage distribution
was IIa = 2, IIb = 4, IVa = 2. The uterus was anteverted in 5 patients andretroverted in 3 patients. All patients underwent initial chemo-radiation to thepelvis, 45 Gy in 25 fractions over 5 weeks. During the fifth of external beam
radiotherapy (EBRT), patients underwent a diagnostic MRI scan to assess response. Following EBRT, patients proceeded to CT-based IGBT, 3-4 fractions
over 8 days.For this study, an initial HR-CTV (HR-CTV-MR) was contoured
on the axial oblique MRI obtained during week 5 of EBRT. The axial oblique
MRI was then fused to the first planning CT with the BT applicator in situ. The
external and internal cervical os were used as fusion points to minimise fusion discrepancy in the region of the cervix. A second HR-CTV (HR-CTV-CT)
and the OAR (rectum, sigmoid and bladder) were outlined on the planning
CT. The concordance of the paired HR-CTV volumes was compared using
the conformity index. Three dosimetry plans were created for each pair of
HR-CTV using different prescription points: point A, D90 of the HR-CTV-CT
and D90 of the HR-CTV-MR. One patient was contoured on all three planning
CTs as her uterine position shifted significantly between BT fractions, making
a total of 10 paired HR-CTV volumes for analysis. A standard loading pattern
was used for each plan with no attempt at plan optimisation.
Results: The mean volume for the HR-CTV-MR and HR-CTV-CT was 12.9
cc and 21.4 cc respectively. The HR-CTV-CT was 1.2-2.4 times larger thanthe HR-CTV-MR (mean 1.7). The conformity index between paired HR-CTV
volumes ranged from 0.35-0.57 (mean 0.43).When 7 Gy was prescribed topoint A, the mean D90 of the HR-CTV-CT and HR-CTV-MR was 8.1 Gy (range
3.5-10.2) and 10 Gy (range 4.2-12.7) respectively (p=0.001). The D90 HRCTV-CT was 67-99% that of the D90 HR-CTV-MR (mean 80%). When 7
Gy was prescribed to the D90 of the HR-CTV-CT, the mean D90 of the HRCTV-MR was 8.4 Gy (range 7.1-10.4). The constraints for the D2cc rectum,
sigmoid and bladder were exceeded in 3, 3 and 2 patients respectively. When
7 Gy was prescribed to the D90 of the HR-CTV-MR, the mean D90 of the HRCTV-CT was 5.9 Gy (range 4.7-6.9). The constraints for the D2cc rectum,
sigmoid and bladder were exceeded in 3, 2 and 2 patients respectively. The
OAR doses were reduced by 1-33% (mean reduction 20%).
Conclusions: The study has shown that the use of CT-MR fusion for HRCTV contouring in IGBT for cervix cancer is feasible and may lead to lower
OAR doses compared to CT-based IGBT alone.
643 poster
GEC-ESTRO VERSUS ICRU 38 DOSIMETRY: THE CO-60 PERSPECTIVE
O. Hayman1 , A. Palmer1 , S. Muscat1
1

Q UEEN A LEXANDRA H OSPITAL, Portsmouth, United Kingdom

Purpose: Ir192 is the conventional isotope used for HDR brachytherapy andis extensively reported in the literature [1]. Co60, is emerging as a viable alternative - this study contributes to the required research on the use of thisisotope in the context of treatment prescription and reporting parameters. A
planning system study which compares CT-based gynaecological brachytherapy plans created using the dosimetric quantities from the GEC-ESTRO guidance against ICRU 38 parameters is reported. Portsmouth Oncology centreis the first department in the UK to use Co-60 for HDR brachytherapy (IBtBebig HDR Multisource), having prior extensive experience of Ir-192 use.
Materials: Six patients received HDR brachytherapy with a ring applicatorand IUT. CT images were used for determining the high-risk clinical target
volume (HRCTV) and for reporting associated GEC_ESTRO dosimetry parameters: V100% and D90Gy. Rectum, bladder and sigmoid volumes were
outlined for determination of D0.1cm3 , D1.0cm3 and D2.0cm3 . ICRU 38
A Points, bladder and rectum points were also positioned. Two optimisedplans were created for each patient, one based on prescription to the HRCTV
and the other on dose to A-points. Doses to the HRCTV and the organs atrisk(OARs) were compared.
Results: The results demonstrate that the dose delivered to the HRCTV isgreater for plans prescribed to the HRCTV compared with those prescribedusing dose to Point A. There is an increase in the V100% and the D90Gy
for all 6 patients with a maximum increase of 2.8Gy in D90Gy.The D2cm3
volume for rectum was less than 80% of the prescription dose for 4 of the 6patients. A decrease was observed across all patients when prescribing to
HRCTV rather than Point A. The same trend is observed with the ICRU rectal
point.The D2cm3 bladder doses are higher, ranging from 59% to 110% whenprescribing to the HRCTV compared to Point A. This is also seen with the

S 261

ICRU 38 bladder point.
Conclusions: When prescribing to the HRCTV, the dose delivered to thevolume is greater than when prescribing to the A -points. This method ofprescribing also reduces the dose to the OAR ICRU dose points and GECESTRO volumes of D2cm3 for the rectum. There are significant differences in
the radial dose function and anisotropy function for Co60 compared to Ir192,
especially along the extension of the central axis of the source. Since themajority of research and guidance in brachytherapy has been generated using Ir192 sources, further investigation into the behaviour of the Co60 source
when prescribing at asymmetric and different distances from the central axisof the source in all directions is necessary. Further work on optimisation
methods in brachytherapy treatment planning is also required. However, theresults presented here have demonstrated that a move from ICRU 38 to GECESTRO based dosimetry is valid for Co-60 sources. [1] The GEC ESTRO
Handbook of Brachytherapy, Gerbaulet A, Potter R, Mazeron JJ, Meertens H,
Van Limbergen E. 2002
644 poster
HIGH DOSE RATE BRACHYTHERAPY FOR UTERINE CERVIXCARCINOMA : COMPARISON OF EFFICACIES AND TOXICITIESBETWEEN TWO DIFFERENT FRACTIONATION REGIMENS
C. Y. Kim1 , C. H. Rim1 , D. S. Yang2
1
KOREA U NIVERSITY A NAM H OSPITAL, Department of Radiation Oncology,
Seoul, Korea Republic of
2
KOREA U NIVERSITY G URO H OSPITAL, Department of Radiation Oncology,
Seoul, Korea Republic ofPurpose: There is no consensus as to the best dose-fractionation regimen
in high dose rate (HDR) brachytherapy for uterine cervix cancer. This study
is designed to compare the efficacies and toxicities between two different
fractionation regimens.
Materials: From September 1992 to February 1998, 235 patients treated byremote controlled HDR brachytherapy at Korea University Medical Center.
Twenty-five patients were excluded due to inadequate follow-up. For 103 patients, intracavitary brachytherapy was delivered with 6 fractions of 4 or 4.5
Gy at point A (Group A), and for 102 patients, intracavitary brachytherapy wasdelivered with 10 fractions of 3 Gy at point A (Group B). There were 1 in situ
patient, 12 stage Ia, 36 stage Ib, 14 stage IIa, 26 stage IIb, 7 stage IIIb, 6
stage IVa, 1 stage IVb in group A and 2 in situ patients, 10 stage Ia, 24 stageIb, 17 stage IIa, 32 stage IIb, 1 stage IIIa, 10 stage IIIb, 5 stage IVa, 1 stage
IVb in group B. There was no significant difference by stage between group
A and group B. The median follow-up time was 73 months. Kaplan-Meiermethod was used to calculate survival and late complication.
Results: The overall 5 year survival was 75.7% in group A and 66.8% ingroup B (p=0.31). The 5 year disease-specific survival was 80.8% in group A
and 72.7% in group B (p=0.34). The 5 year local control rate was 89.1% ingroup A and 89.4% in group B (p=0.61). The 5 year cumulative incidence ofgrade 3 or higher gastrointestinal(GI) late complication were 3% in group A,
2% in group B (p=0.32) and grade 3 or higher genitourinary(GU) late complication were 1% in group A and 2% group B (p=0.14).
Conclusions: Overall survival, disease specific survival and local control rate
were comparable among 2 groups. Grade 3 or higher GI and GU late complication was no significant differences between Group A and Group B(p=0.32,
p=0.14). Schedule of 6 fractions(Group A) may provide convenience to patients by shorter treatment time.
645 poster
IMPACT OF DELINEATION ERROR ON DOSE TO ORGANS AT RISKIN IMAGE-GUIDED BRACHYTHERAPY.
F. Duane1 , C. Gillham1 , G. Rangaswamy1 , L. Walsh1 , C. Lyons1 , M.
Dunne2 , B. Langan3 , C. Walker3 , O. McArdle1
1
S T. L UKE ’ S H OSPITAL, Department of Radiation Oncology, Rathgar, Dublin
6, Ireland Republic of2
S T. L UKE ’ S H OSPITAL, Clinical Trials Unit, Rathgar, Dublin 6, Ireland
Republic of3
S T. L UKE ’ S H OSPITAL, Department of Physics, Rathgar, Dublin 6, Ireland
Republic ofPurpose: Target delineation is a potential source of significant error in thetreatment planning process. The purpose of this study is to quantify the interobserver and intra-observer variation in contouring organs at risk (OARs),an essential step in image-guided brachytherapy for the treatment of cervicalcarcinoma. The dosimetric consequences of this variation are reported inaccordance with current GEC-ESTRO guidelines for OAR dose calculations.
Materials: A retrospective CT planning study including 8 consecutive women
undergoing brachytherapy for cervical cancer was conducted. All patients
had CT scans performed with the applicator in situ and 25mls of contrast
placed in the bladder via urinary catheter. Bladder, rectum and sigmoid were
contoured by 5 blinded observers on 2 identical anonymised scans from eachof the 8 patients according to a delineation protocol.This provided 80 scans
for analysis. Dosimetric parameters analysed were D0.1cc, D1cc and D2cc.

S 262B RACHYTHERAPY: G YNAECOLOGYB RACHYTHERAPY: G YNAECOLOGY

Mean volume of each OAR was calculated. These endpoints were compared
between and within observers.
Results: The inter-observer coefficient of variation for reported D2cc was
13.2% for the bladder, 9% for the rectum, and 19.9% for the sigmoid. Mean
D2cc (range) was 5Gy (3.0-6.9) for bladder, 3.1Gy (2.4-3.5) for rectum and3.9Gy (2.3-6.7) for sigmoid. The median intra-observer variation for reported
D2cc ranged from 2.6-9.6% for the bladder, 1.4%-9.5% for the rectum and2.5-40.7% for the sigmoid. Bladder and rectal contours largely agreed on
anatomy but varied in interpretation of visual data i.e. small differences inplacement of the posterior wall of the bladder. In contrast, sigmoid contours
varied in anatomical interpretation i.e. inclusion or not of entire loops of sigmoid.

Conclusions: Delineation variation is a source of error in the image-guided
BT planning and delivery process. Inter-observer variation in D2cc to thebladder and rectum is comparable to previous published results. Inter- andintra-observer variation in reported D2cc is markedly high for the sigmoid,reflecting varying interpretation of sigmoid anatomy. The recorded dose received by each OAR may vary accordingly and this may significantly influenceplanning optimisation.
646 poster
IMPACT OF INFORMATION FROM FIGO STAGE +/- 3D CLINICALDRAWING ON HRCTV DELINEATION FOR CT BASED CERVICALCANCER BRACHYTHERAPY WITH STANDARDIZED LENGTHS
N. Hegazy1 2 , N. Nesvacil2 , M. Federico2 , A. Sturdza2 , E. Fidarova2 , C.
Kirisits2 , R. Pötter2
M EDICAL U NIVERSITY OF A LEXANDRIA, Department of Clinical Oncology,
Alexandria, Egypt
2
M EDICAL U NIVERSITY OF V IENNA, Department of Radiotherapy, Vienna,
Austria1

Purpose: The introduction of 3D MRI based brachytherapy in the treatmentof cervical cancer patients allowed evaluation of individual dose distributions
applied to a certain volume and provided dose volume histograms for proper
estimation of the dose in relation to the target volumes and OAR. Although
MRI is superior to CT in identifying cervical cancer extension, some institutions do not have an access to an MRI unit or their unit is located at a significant distance from the radiation oncology unit. The aim of our study wasto evaluate the feasibility of CT based HRCTV delineation using only staging
information +/- clinical examination and assess the impact of using different
length of uterus on CT based HRCTV volume contouring.
Materials: Twenty patients with cervical cancer (7 FIGO stage IB, 7 FIGO
stage IIB, and 6 FIGO stage III) received definitive chemoradiotherapy (45-50
Gy EBRT and 4 fractions of MRI guided BT of 7 Gy) between 2007 and 2010.
All patients had both CT and MRI with applicator in place, and clinical drawing in 3D indicating results of clinical examination at the time of brachytherapy.
The CT at the time of brachytherapy was used to delineate HRCTVstage on
basis of CT information and FIGO staging. HRCTVstage+3Dclin was contoured based on clinical examination at the time of BT with 3D clinical drawing additional to the abovementioned data. As length of tumour cannot be
assessed by staging and clinical examination, we performed contouring using three different lengths for HRCTV: whole uterus, two thirds of uterus andhalf of uterus, resulting in six target volumes for each patient. The resulting
HRCTV volumes and dimensional parameters were normalized to the respective parameters of original MRI guided HRCTV delineated on MRI at the timeof brachytherapy.
Results: When whole length of uterus was used, the normalized median volumes for HRCTVstage and HRCTVstage+3Dclin were 2.6±0.6 and 2.1±0.5
respectively. When two third of uterus, was used, normalized median volume
for HRCTVstage was 2.3±0.5 and for HRCTVstage+3Dclin was 1.8±0.4.
For half of uterus, the normalized median volumes for HRCTVstage and
HRCTVstage+3Dclin were 1.9±0.4 and 1.5±0.3.The normalized height values for HRCTVstage were 1.6±0.3 (whole uterus), 1.3±0.2 (2/3 of uterus)and 1.1±0.2 (half of uterus), while for HRCTVstage+3Dclin were 1.5±0.3,
1.2±0.2 and 1.02±0.2. Three patients had tumor involving more than half ofuterus. The resulting normalized width values were 1.5±0.3 for HRCTVstage
and 1.2±0.2 for HRCTVstage+3Dclin.
Conclusions: In centres with no or limited access to MRI, CT-based delineation of HRCTV may be applied as a tool of contouring for 3D image
guided adaptive BT when it is accompanied by reproducible 3D clinical drawing based on 3D precise clinical examination in addition to FIGO stage; although there is need for more improvement. The inclusion of one half of whole

length of uterus as standard length of the HRCTV results in target coveragecomparable to the original MRI HRCTV, in particular for small tumours.
647 poster
INDIGENOUSLY DESIGNED CUSTOM MADE PERINEAL TEMPLATEFOR INTERSTITIAL BRACHYTHERAPY IN RECURRENT CARCINOMA CERVIX
M. Kumar1 , S. Bhaskaran1 , B. Satheesan2
1
M ALABAR C ANCER C ENTRE, Radiation Oncology, Kannur, India
2
M ALABAR C ANCER C ENTRE, Surgical Oncology, Kannur, India
Purpose: Interstitial Brachytherapy is generally used for patients either withextensive pelvic and/or vaginal cancers or when anatomy does not allow intracavitary brachytherapy with standard applicators. We report the treatment
outcome for a patient with carcinoma of cervix with lower vaginal recurrence
treated with interstitial brachytherapy using indigenously designed custom
made template.
Materials: Interstitial implantation is a brachytherapy technique performed
by inserting radiation sources into the needles or catheters placed directly
into the tumor. We used a custom made afterloading template to treat thelesion which was lower vaginal recurrence. The device basically consists ofa set of templates made of thermoplastic sheets with a predrilled array ofholes of diameter 1.9mm that allows placement of the metallic needles. The
templates have an axial hole large enough to pass a central tandem. The
central tandem provides provide better template stability and additional treatment options. Needle positions were selected to adequately encompass thetumor. Hollow, closed-end, stainless steel trocars of diameter 1.9mm (12-20
cm long) are then inserted through the guide holes into the tissues undertransrectal ultrasound guidance that produce optimal coverage of the treatment volume. Guide holes are designed to allow the inserted needles lie inparallel horizontal planes, perpendicular to the template plane. The planes
are spaced vertically one cm apart. The needles are arranged with a spacingof 1 cm between adjacent needles. Planning CT scan is done to for confirmation of the needle positions and for CT-based treatment planning to evaluate
the dose distribution. Radiation dose distribution was calculated using the
PLATO Brachytherapy Planning System and was adjusted to achieve optimal tumor coverage with maximal dose uniformity and acceptable bladderand rectal doses. The HDR dose 10 Gy prescribed at the first isodose linethat contiguously included all of the needles at 5 mm from the needles wasused. Implant needles were then connected to the HDR brachytherapy machine with the transfer cables. The radiation was delivered with the 10-Curie
Iridium-192 source in the brachytherapy room using remote controlled afterloading technique. Two sessions one week apart was done under epidural
analgesia.

Results: The patient achieved complete tumor regression on last follow up at
three months.
Conclusions: The advantages of the technique are that the template being
custom made is suitable for that particular case. It turns out to be lot cheaper
than MUPIT (Martinez universal perineal interstitial template) or other imported perineal templates. Such designing is possible, practical and can bedone as individualized template treatments.

S 263

648 poster

650 poster

INTERSTITIAL BRACHYTHERAPY IN GYNECOLOGICAL MALIGNANCIES - SINGLE INSTITUTION EXPERIENCE
V. Anand1 , M. Lala2 , V. Kannan1 , K. Keditsu2 , S. Deshpande1
1
P.D. H INDUJA N ATIONAL H OSPITAL, Department of Radiation Oncology,
Mumbai, India
2
P.D. H INDUJA N ATIONAL H OSPITAL, Department of Surgical Oncology,
Mumbai, India

INTRODUCTION OF MRI IMAGE GUIDED BRACHYTHERAPYIN INTRACAVITY BRACHYTHERAPY FOR CERVICAL CANCER:
IMPACT ON OUTCOME AND MAJOR TOXICITY
R. Cooper1 , P. Bownes2 , E. S. Choong1 , E. Brealey2 , C. Richardson2 , S.

Purpose: Technological advances has improved therapeutic outcomes in advanced gynecological malignancies, utility of High Dose Rate brachytherapy(HDRBT) along with external radiation therapy has demonstrated superior
control of disease.
Materials: 26 patients with epithelial gynecological malignancies were retrospectively analyzed who were treated over a period of 5 years from July 2005
to July 2010. Sixteen patients with carcinoma cervix, eight with vaginal vault
recurrence and two with carcinoma vulva were included in the study. FIGO
staging of cervical cancer patients were : IB2 in 1, IIB in 7, IIIA in 1, IIIB in 4,
IVA in 2 and IVB in 1 patient, staging of vulval cancer was stage II in two patients . The median age was 57 years (Range 44-76 years). Vaginal bleeding
was the most common presenting symptom in 19 patients (73%) and the median duration of symptoms was 2 months (Range 2 weeks to 18 months). All
patients received external beam radiotherapy (EBRT) followed by fluoroscopy
guided interstitial brachytherapy using a SYED-NEBLETT template. The median dose of EBRT received was 45 Gy in 25 fractions (Range 28 Gy 60
Gy) and median dose of interstitial brachytherapy 22 Gy in 4 fractions (Range
11 36). Seventeen patients received concurrent chemotherapy. All patients
received weekly Cisplatin dose of 40 mg /m2 except one who received carboplatin with an average of 5 cycles.
Results: Median follow-up was 21 months (6 to 54 months). Averagebrachytherapy dose to 2cc rectum was 16.5 Gy, two patients developed grade
I and one Grade II rectal toxicity and none experienced any bladder toxicity
as per the RTOG-LENT scale. Average brachytherapy prescription dose covering planning tumor volume (PTV) was 79.62%. Disease free survival was
73.9 % and overall survival was 78.2%.
Conclusions: Combined modality offers better tumor control and reduced
treatment related toxicity. Adding interstitial brachytherapy as integral part ofradiation therapy in the management of gynecological malignancies achieves
superior local control.
649 poster
INTRA-FRACTIONAL APPLICATOR AND ORGAN AT RISK MOVEMENT DURING PULDE DOSE RATE BRACHYTHERAPY FORCERVICAL CANCER
J. Gilmore1 , I. Dumas2 , T. Messai1 , R. Mazeron1 , C. Haie-Meder1
1
I NSTITUT G USTAVE R OUSSY, Brachytherapy Department, Villejuif, France
2
I NSTITUT G USTAVE R OUSSY, Physics , Villejuif, France
Purpose: To use computed tomography to assess the intra-fractional movement of customized utero-vaginal applicators in three dimensions during
pulse dose-rate brachytherapy. To, similarly, assess the intra-fractional movement of organs at risk (OARs) and the dosimetric impact of such movement.
Materials: A prospective study of 12 patients was undertaken. Brachytherapy
planning for these patients was MRI based. After the MRI, each patient proceeded to have a CT scan. CT scans were performed, with BT device in situ,
on day 0 (d0), day 1 (d1) and day 2 (d2) of the brachytherapy treatment. The
3 CT scans for each patient were fused using d0 as the reference scan. Displacement and volume variation of OAR were assessed. The utero-vaginal
applicator was contoured on each of the patients scans and movement assessed at the level of the tip of the uterine tandem and at the junction where
the uterine tandem meets the vaginal applicator. Movement was assessed in
the antero-posterior, lateral and sup-inf directions. Doses for the 2 cc tissue
volume (D2cc) for the rectum, bladder and sigmoid were calculated on each
CT scan.
Results: Variation of rectal volume between d0, d1 and d2 was statisticallysignificant (p=0.04). For the bladder, and the sigmoid, this difference was
not statically significant. The rectal isocenter displacement between the 3
CT exams was statistically significant in the cranio-caudal direction (p=0.038)
and the antero-posterior direction (p=0.016). Movement of the applicator was
most significant at the level of the tip of the uterine tandem in the ant-post
direction. This was most significant between d0 and d2.
Conclusions: Applicator movement and significant differences for major dosimetric parameters were found during the course of these patientsbrachytherapy treatment. This has significant implications for the timing ofplanning for PDR and the accepted doses to OARs. These results encourage
further assessment of the optimal timing for dosimetric planning in intracavitary PDR-BT in a larger cohort.

Swift3 , C. J. Orton1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Department of Clinical Oncology, Leeds, United Kingdom
2
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Department of Medical Physics, Leeds, United Kingdom
3
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Department of Radiology, Leeds, United Kingdom
Purpose: This study reports the clinical outcome following the introductionof using optimised treatment plans based on GEC-ESTRO recommendationsfor MRI defined target volumes.
Materials: Between 01/2008 and 07/2010 48 patients have been treated with
MRI image guided brachytherapy. Treatment consisted of 48Gy in 24 fractionsof conformally planned EBRT combined with weekly cisplatin (40mg/M2 ), followed by 21Gy in 3 fractions to point A or the high risk clinical target volume (HRCTV). All patients, underwent MRI with the applicators in place on
fraction one (at least) and a CT with each fraction. Using image registration techniques and the assumption that the HRCTV, is fixed with respect
to the applicator the HRCTV is transferred onto the subsequent fraction CT
image sets. Total doses were normalised as 2Gy equivalent dose using
a/b=10Gy for tumour and a/b=3Gy for the organs at risk. We aimed to for
a HRCTV(D90) of 84Gya/b=10Gy, and D2CC to bladder <90Gya/b=3Gy andrectum/sigmoid/small bowel <75Gya/b=3Gy. Late toxicity was LENT-SOMA
scoring system.
Results: The median follow-up was 12 months (4-32). The stage was IB1 in
3, IB2 in 6, IIA 4, IIB, 29, IIIB 2, IVA, 1 and IVB 3. The majority were node
positive (3 para-aortic disease). 41 patients were treated with a standard planfor the first fraction, and 7 patients were treated with a conformal plan for all
fractions, including one patient treated with the interstitial ring applicator. For
those treated with a standard plan to point A for fraction one a conformal plan
was generated retrospectively and assessed prior to the subsequent fractions
to see if a benefit was observed. 33 patients received a conformal treatment
on at least one of their subsequent fractions. The remainder were treatedusing a standard plan to point A for all fractions. The dosimetry of the 40
patients, who received at least one conformal treatment, showed that using
three dimensional optimisation, four out of five of the dosimetric aims were
met in 38 out of 40 patients. In this series 31 out of the 40 patients were
optimised principally to reduce the dose to the organs at risk. The remaining
patients were optimised to improve both HRCTV coverage and OAR dose
sparing. Patients who did not benefit from optimisation already met four out offive of the dosimetric aims. Mean HRCTV D90 using optimisation was 96±10Gya/b=10Gy and volume of HRCTV encompassed by the 100% isodose was98±3%. The D2cc for the bladder, rectum, sigmoid and small bowel was
82±10, 65±6, 65±8 and 60±7 Gya/b=3Gy respectively.1 patient (2%) have
had a local recurrence, 2 (4%) had regional recurrence, 2 (4%) metastatic
recurrence and 1 (2%) regional and distant. Two patients had grade 3/4 bowel
toxicity, 1 bladder and 4 skeletal.
Conclusions: MRI guided brachytherapy following the GEC-ESTRO guidelines for cervical cancer has enabled 3D optimisation. Initial clinical results
indicate excellent local control with acceptable late toxicity.
651 poster
LONG TERM RESULTS OF THE COMBINED RADIOTHERAPY(INCLUDING CF-252 HDR BRACHYTHERAPY) FOR CERVICALCARCINOMA
V. Atkocius1 , E. Janulionis1 , K. P. Valuckas1 , V. Samerdokiene1
1
I NSTITUTE OF O NCOLOGY V ILNIUS U NIVERSITY, Vilnius, Lithuania
Purpose: To estimate long term survival of the cervix carcinoma patients (IIB, III B) treated by combined RT using Cf-252 brachytherapy.
Materials: During period October 1, 1996 March 31, 1998 combined radiotherapy (RT) was prescribed for 131 patients with cervix carcinoma. We
present data regarding treatment results of the 100 patients who have completed combined RT: 30 pts with stage II B and 70 III B. 30 pts have notcompleted combined radiotherapy: 27 pts received only external Co-60 gammatherapy and 3 only brachytherapy. One pt was excluded with stage I B. All
pts received external Co-60 gammatherapy (median dose point B: II B 44,0
± 4,9 Gy, III B 50,0 ± 4,2 Gy) and Cf-252 HDR brachytherapy (median dosepoint A: II B 40,0 ± 7,4 Gyeq, III B 40,0 ± 6,5 Gyeq) in 5 fractions.
Results: The case records were collected at the Institute of Oncology, Vilnius University as well as the data of the Cancer Registry (31 December2009).Stage II B. Overall 5 yr and 10 yr survival was 73,3 % and 66,7 % respectively. There was no statistically significant survival according Hb level(≥ 120 g/l vs < 120 g/l). The 1 relapse have been found in this group. Stage
III B. Overall 5 yr and 10 yr survival was 48,6 % and 45,7 % respectively.
There was statistically significant survival (p<0.0001) according Hb level 29,0
% and 25,8 % vs 61,5 % and 61,5 % for <120 g/l and ≥ 120 g/l for the sur-S 264B RACHYTHERAPY: G YNAECOLOGYB RACHYTHERAPY: G YNAECOLOGY

vival 5 yr and 10 yr respectively. 5 pts developed relapses. The 4 second
primaries (min 1 yr after treatment) have been recorded: 2 for stage II B and
2 for stage III B.
Conclusions: The high survival rates have been estimated for cervix uteri
carcinoma II B and III B after combined RT including Cf-252 HDR brachytherapy.
652 poster
MAGNETIC RESONANCE IMAGING-GUIDED BRACHYTHERAPYFOR CANCER OF CERVIX: CLINICAL RESULTS
E. Villafranca Iturre1 , P. Romero1 , V. Chicata1 , S. Pellejero2 , S. Lozares2 ,M. Vila1 , A. Sola1 , M. Rico1 , M. Dominguez Dominguez1 , J. C. Muruzabal3 ,C. Sanchez4
1
C OMPLEJO H OSPITALARIO DE N AVARRA, Department of Radiation
Oncology, Pamplona, Spain
2
C OMPLEJO H OSPITALARIO DE N AVARRA, Medical Physics, Pamplona,
Spain
3
C OMPLEJO H OSPITALARIO DE N AVARRA, Gynecology oncology, Pamplona,
Spain
4
C OMPLEJO H OSPITALARIO DE N AVARRA, Radiology, Pamplona, Spain

Materials: We have performed a retrospective review of 12 patients withcervical cancer who have been treated with radical external beam radiotherapy (EBRT) followed by intrauterine pulsed dose rate (PDR) brachytherapy between June 2009 and July 2010. All patients received 50.4Gy 28#
1.8Gy/# EBRT. On completion of EBRT a single intrauterine tube is inserted
for brachytherapy delivery. Retrospectively we contoured the outer wall of the
bladder, rectum and sigmoid on the planning CT scan according to the GECESTRO guidelines and have calculated the D2cc for each organ. The rectum
was defined as starting at the anal verge and extended cranially to the inferior extent of the sacro-iliac joints. The sigmoid was outlined from this point to
2cm above uterus. We accepted a D2cc rectum, sigmoid and bladder cumulative dose tolerance of 75Gy, 75Gy, and 90Gy respectively, as recommended
by GEC-ESTRO.
Results: Of our 12 patients only 3 received 26Gy to the Oxford prescription
point. In the remaining 9 patients the dose was modified to between 18-24Gy
due to concerns of exceeding previously recommended maximum cumulative rectal or bladder point doses. On reviewing the D2cc for each organ atrisk, using the GEC-ESTRO guidelines, the prescribed dose to all of these9 patients could have been increased without exceeding the GEC-ESTRO
recommended D2cc dose limits.

Purpose: To determine the local control and toxicity in patients with cervix
cancer using optimized magnetic resonance imaging guided brachytherapy(MR-IBT)
Materials: Between May 2008 and September 2010, a total of 26 patientswith cervical cancer FIGO Stage IIB-IIIB were treated in our Hospital. All ofthem were studied with pelvic MRI, abdominal CT and laparoscopic paraorticpelvic lymphadenectomy. They received a total dose of 45 Gy with external beam radiation therapy concomitant to weekly cisplatin 40 mg/m2. Two
weekly sessions from a total of 5 fractions of BT insertions with 6 Gy eachwere delivered the week after pelvic EBRT (RTOG)MRI-compatible intrauterine BT applicator (Nucletron®) was used. MRI scans were acquired after
the insertion of the applicator. Gross Tumor Volume at diagnosis and at BT,
high-risk (HR- CTV) and intermediate-risk clinical target volume (IR-CTV),and rectal, sigmoid, and bladder were delineated according to GEC-ESTRO
guidelines.HDR-BT was planned and delivered based in MRI.
Results: Clinical results: 22 patients (p) with histology of squamous cell carcinoma and 4 p with adenocarcinoma. Stage: T1b2 2p, T2b 21p, T3b 2p andT4a 1p; N0 18p, pelvic nodes 5p, paraortic nodes 3p. At a median follow-up
of 20 months, all patients are alive with a complete response after MRI andbiopsies. The locoregional control is optimal in all patients and only one had adistant metastatic recurrence.Toxicity: rectal-sigmoid G2 in 3p (8%), uretheral
stenosis in 1p (4%).Dosimetrical results: The HR-CTV and intermediate-risk
CTV were adequately treated in 24 of 26 implants: D90 HR-CTV: median132.5 % (range: 114-183%). In two patients, the coverage of HR-CTV was
suboptimal and the implant was modified to an interstitial implant, the first one
with a MUPIT applicator and the second using the Utrecht applicator. With
MR-IBT optimization the median mean dose to the 2cm3 of rectal, sigmoid,and bladder wall volume was 68.7%, 72.9% and 86.1% respectively.
Conclusions: MRI-based BT for cervical cancer made a low urinary andrectal toxicity and an optimal locoregional control, although a longer following
period is needed.

Conclusions: When compared to conventional radiography-based approach, MRI-assisted treatment planning improves the DVH parameters fortarget volume and OAR in cervix cancer brachytherapy. The clinical impact of
this improvement on our patient series will be reported after a longer follow
up.
655 poster
MRI-GUIDED INTRACAVITARY BRACHYTHERAPY FOR CERVICALCANCER – DVH PARAMETERS AND OUTCOMES OF A PROSPECTIVE TRIAL
L. Walsh1 , M. Morgia1 , X. (. Xie2 , J. Jezioranski2 , J. YAN2 , Y. B. CHO2 , A.
Fyles1 , M. Milosevic1
1
P RINCESS M ARGARET H OSPITAL, Department of Radiation Oncology,
Toronto, Canada
2
P RINCESS M ARGARET H OSPITAL, Department of Radiation Oncology andMedical Physics, Toronto, Canada

653 poster
MOVING TOWARDS GEC-ESTRO GUIDELINES IN CERVICALCANCER BRACHYTHERAPY. THE OXFORD CANCER CENTRE
EXPERIENCE.
S. Jonnada1 , M. Costelloe2 , A. Foulsham3 , S. Trent4
1
C HELTENHAM G ENERAL H OSPITAL G LOUCESTERSHIRE H OSPIT, Department of Radiotherapy, Cheltenham, United Kingdom
2
C HURCHILL H OSPITAL, Department of Physics and Radiotherapy, Oxford,
United Kingdom
3
C HURCHILL H OSPITAL, Department of Radiotherapy, Oxford, United
Kingdom
4
C HURCHILL H OSPITAL, Department of Radiation Oncology, Oxford, United
Kingdom
Purpose: The GEC-ESTRO working group issued guidelines for 3D based
treatment planning in cervical cancer. This included guidelines for outlining the tumour volume and also the organs at risk (OAR). In May 2009 wechanged our intrauterine brachytherapy policy at the Oxford Cancer Centre,
we moved from LDR to PDR brachytherapy. Initially at the time of the changeover we attempted to prescribe a dose of 24Gy to the Oxford prescription
point (2cm lateral to the midpoint of the treatment height in the intra-uterinetube); this was then increased to 26Gy in May 2010 following review of radiobiological evidence. For each individual insertion the prescribed dose wasmodified according to maximum rectal and bladder point dose as defined byclinicians on the CT scan performed with the intrauterine tube in situ. We
accept a maximum cumulative rectal point dose of 72Gy and bladder point
dose of 75Gy. The ICRU reference points for bladder and rectum are also
recorded.

radiographs with the applicator in place. Implementation of 3D imaging into
treatment planning enables optimization of dose-volume histogram (DVH) parameters for the target volume and organs at risk (OAR). We report on theintercomparison of DVH parameters, obtained by conventional radiographyand MRI- based treatment planning.
Materials: 48 patients with locally advanced cervix cancer, treated at our
institution between June 2006 and August 2009 were included. Following
3D conformal external beam radiotherapy (EBRT) of the pelvis (45-50.4 Gy
in 25-28 fractions) with or without concurrent chemotherapy and paraaortic
field irradiation, 2 weekly applications of MRI guided adaptive BT were performed. GTV, HR CTV, IR CTV, bladder, rectum and sigmoid colon were
contoured according to GEC-ESTRO recommendations. The standard nominal prescribed dose was 18.5 Gy per insertion, applied in 25 hourly pulses.
Total dose (EBRT+BT), normalized to equivalent dose in 2 Gy fractions (α/β10 and 3 Gy for tumor and OAR, respectively; repair half-time: 1.5 h) was
calculated. Conventional loading (dose prescription at point A) was used as
starting point for dose planning. Next, source dwell-times and positions were
optimized, when indicated, aiming at a total D90 for the HR CTV of 90 Gy
and V100>90%, while respecting our OAR dose constraints (bladder D2cc
<75 Gy; rectum and sigmoid D2cc <70 Gy). Mean HR CTV size was 35
cm3 (13-99 cm3 ). DVH parameters of conventional and MRI-based treatment
plans were compared separately for the patients with small and large tumors
at BT (<35 cm3 and >=35 cm3 ).
Results: In small tumors, an exceedingly high mean D90 of 101 Gy (st. dev.
16 Gy) for HR CTV was achieved by conventional plans, while OAR dose
constraints were violated in 53% of cases. In large tumors, conventional plans
resulted in a mean D90 of 84 Gy (st. dev. 11 Gy), while OAR dose constraints
were violated in 30% of cases. MRI-based optimisation equalized the mean
D90 value at 90 Gy both for small (st.dev. 4 Gy) and large (st.dev. 5 Gy)
tumours, while reducing violation rate for OAR dose constraints to 6% and
8%, respectively. Large standard deviations on DVH parameters, obtainedwith conventional plans, reflecting high variation between individual values,
were reduced by MRI-based optimization (Table).

Conclusions: Using the GEC-ESTRO guidelines we hope to optimise thedose to the cervix whilst avoiding excessive toxicity to the organs at risk. We
hope that this translates into better local control rate. Prospective toxicity data
is being collected.
654 poster
MRI ASSISTED TREATMENT PLANNING IMPROVES THE DVH
PARAMETERS IN CERVIX CANCER BRACHYTHERAPY
P. Petric1 , R. Hudej1 , B. Segedin1 , H. B. Zobec Logar1
1
I NSTITUTE OF O NCOLOGY L JUBLJANA, Department of Radiotherapy,
Ljubljana, Slovenia
Purpose: Most common method of treatment planning in cervix cancer
brachytherapy (BT) is still based on 2D systems of points, defined on pelvic

Purpose: To determine initial tumor response rates and analyze dose volume
histogram (DVH) parameters, as recommended by GEC ESTRO, utilizing optimized MRI-guided brachytherapy (BT) for locally advanced cervical cancer.
Materials: BT plans of 50 patients (pts) (treated with 45-50Gy EBRT andweekly cisplatin from Oct 2008 - Dec 2010), and enrolled on a prospective
trial evaluating MRI-guided PDR BT, were evaluated. Patients had a single
intrauterine insertion of a custom-made MRI-compatible single-line source
applicator. The minimum dose (Gy) delivered to 90% (D90) & 100% (D100) of
the high-risk (HR) and intermediate-risk (IR) CTV, and the percentage HR andIR volume encompassed by > 100% target dose (V100) was calculated foreach patient. The maximal dose (Gy) delivered to 0.1, 1, and 2cm3 (D0.1cc,
D1cc, D2cc) of the organs-at-risk (OARs) was evaluated. Pts achieving complete treatment response (CR) (assessed clinically and by 3-month MRI) was
determined. Toxicity was prospectively recorded.
Results: FIGO stage was I, II, III, in 15, 12, 23 pts respectively. Median overall treatment time was 42 days (34-85). Median BT and overall total dose was
40Gy (17 - 45) and 85Gy (62.4 - 90.4) respectively. With a median follow-up of
442 days, 45 pts have had 3 month clinical assessment and MRI performed.
CR occurred in 40 (90%) pts and 2 (4%) had progressive disease. 3 (6.7%)
pts had a partial response: 1 had later local and distal progression, 1 had normal clinical examination but residuum on MRI, and 1 had residuum on clinicaland MR assessment. Grade 3 late gastrointestinal and vaginal toxicity occurred in 2 (4%) and (8%) pts respectively. HR CTV D90 was > 87Gy in 46(92%) pts (Table 1). HR CTV and IR CTV were adequately treated (% volume
treated to > 100% of intended dose was > 95%) in 40 (80%) and 49 (98 %) pts

S 265

respectively. Bladder D2cc was <90Gy in 44 (88%) pts. Rectum and sigmoid
D2cc was <75Gy in 41 (82%) and 29 (58%) pts respectively.There was no
significant correlation between response and DVH parameters, or between
OAR dosimetry and toxicity.

Conclusions: Optimized MRI-guided PDR BT using a single line-source applicator, without ovoids or a ring, adhered closely to GEC-ESTRO DVH parameters in this pt group. This method leads to highly satisfactory response
rates, with acceptable toxicity.
656 poster
MULTI FRACTION HDR BRACHYTHERAPY FOR CERVIX CANCER
DURING ONE HOSPITALIZATION: PRELIMINARY RESULT PHASE II
S. Guérif1 , A. Berger2 , B. Lavigne3 , O. boissonade3 , C. Chung2 , P.
Regnault2 , X. Fritel4 , R. J. Bensadoun5
1
PRC CHU, BRACHYTHERAPY SUITE, POITIERS, France
2
PRC CHU, Department of Radiation Oncology, POITIERS, France
3
PRC CHU, Division of Medical Physics in Radiation Oncology, POITIERS,
France4
P ÔLE M ÈRE ENFANT CHU, Gynecology Department, Toulouse, France
5
CHU DE P OITIERS, Department of Radiation Oncology, Poitiers, France
Purpose: The cervix HDR brachytherapy is usually realized in several applications with local or general anesthesia. The access to the anesthesia islimiting the activity of brachytherapy. We propose to evaluate a multifraction
HDR brachytherapy with one application under local or general anesthesia for
cervix cancer during one hospitalization.
Materials: From April 2010 to December 2010, we began the first step (D90HRCTV= 4,6 gy point A) of a phase II study with inform consent. In patients with bulky disease EBRT was performed with a four-field box techniqueusing a linear accelerator. A total dose of 45 Gy was applied in five fractions of
1.8 Gy weekly. High dose rate (HDR) brachytherapy was performed with five
fractions within tree days, with a time interval of at least 6 h between two consecutive fractions (4,6Gy/fraction), starting in two week after EBRT. In caseof small tumors, High dose rate (HDR) brachytherapy was performed before
surgery with nine fractions within five days, with a time interval of at least
6 h between two consecutive fractions (4,6Gy/fraction). The Bladder werefilled with 50cc threw the catheter before each fraction. We use MRI based
Brachytherapy with Brachyvision. First step we use Vienna standard Loading with prescribe dose on point A. The D90HRCTV = Dose point A. Then
we optimize manual with the local stepper in order to respect constraints on
HRCTV and D2cc OAR. For each patient, the cumulative dose was computed, consisting of EBRT and brachytherapy contribution, normalized to 2
Gy per fraction (Diso) with an α/β ratio of 10 Gy. The iso-doses with of D2cc
for the rectum, sigmoid and small bowel was low than 75 gy and Bladder <90
gy.
Results: From April 2010 to December 201020 brachytherapies (14 ring andtandem, 5 ring and tandem with free needles), 16 brachytherapy + EBRT, 4

S 266B RACHYTHERAPY: G YNAECOLOGYB RACHYTHERAPY: G YNAECOLOGY

bachytherapy alone + surgery. Median follow-up was 4 mouths. 16 bulky disease and 4 small tumors 2IIIa, 12IIb, 1 IIa, 4 Ib. 10 total clinical respons. 3/4
histological complete response Acute Toxicity CTCAE v3.0 : Urinary symptome 5 G0, 10 G1, 5 G2,< 15 days. No grade > G2. No Digestive toxicity. 10
total clinical response. 3/4 histological complete response .
Conclusions: The first step Diso 50gy with an α/β ratio of 10 Gy in 9*4,6gy
for brachytherapy before surgery and Diso 72gy with an α/β ratio of 10 Gy
in 5*4,6gy with EBRT 45gy is well tolerate. The study continu in order to test
the second step with Diso 75gy on D90HRCTV. The goal is to prescribe Diso
85 gy on point A as GEC ESTRO recommendation.

658 poster
PATHOLOGIC COMPLETE REMISSION AFTER PREOPERATIVEHDR BRACHYTHERAPY IN PATIENTS WITH OPERABLE CERVIXCARCINOMA
J. Vízkeleti1 , I. PETE2 , I. Vereczkey3 , G. Fröhlich1 , S. Varga1 , T. Pulay2 , M.
Kásler4 , C. Polgár1
1
N ATIONAL I NSTITUTE OF O NCOLOGY, Radiotherapy, Budapest, Hungary
2
N ATIONAL I NSTITUTE OF O NCOLOGY, Gynaecology, Budapest, Hungary
3
N ATIONAL I NSTITUTE OF O NCOLOGY, Pathology, Budapest, Hungary
4
N ATIONAL I NSTITUTE OF O NCOLOGY, Budapest, Hungary

657 poster
OPTIMISATION TECHNIQUE FOR MRI BASED 3D TREATMENTPLANNING FOR HDR BRACHYTHERAPY CERVIX TREATMENTS
S. Aldridge1 , G. Block1 , M. Naeem1 , R. Johnstone1 , S. Humphreys1 , A.
Winship2
1
G UY ’ S & S T. T HOMAS ’ NHS F OUNDATION T RUST, Department of Medical
Physics, London, United Kingdom
2
G UY ’ S & S T. T HOMAS ’ NHS F OUNDATION T RUST, Department of ClinicalOncology, London, United Kingdom
Purpose: Intracavitary brachytherapy (BT) plays a crucial role in the therapeutic management of patients with invasive cervical carcinoma from stage
IB2 to IV. MRI has been proven to be the gold standard for target and organ
at risk (OAR) delineation for BT cervix treatments enabling the dose distribution to be conformed to the target for individual patients. We implemented
MRI based 3D treatment planning for HDR BT treatments of cervical carcinoma following the GYN GEC-ESTRO recommendations in May 2010 andhave optimised treatment plans for every patient to date. This work assesses
the value of the optimisation process by comparing the optimised plans withalternative standard plans.
Materials: MR and CT scan scans are acquired for every BT fraction. The
3D image sets are fused, the MR images are used to delineate the target
and critical structures (OAR), and the CT images are used for applicator reconstruction (Rotterdam). A standard plan (set-up during commissioning tomimic dose distributions of Manchester LDR loadings) is viewed. The plan isthen optimised as required to keep the OAR below tolerance and to achieverequired target doses.
Results: 100% of our treatment fractions (8 patients, 3 fractions, 24 plans)required individual plan optimisation following standard plan evaluation. We
used a variety of optimisation techniques; including removing the dwell positions from the top of the IUT (15/24), using asymmetric dwell times in the
ovoids (16/24) and using asymmetric ovoid sizes (13/24). In the majority of
individual fractions these optimisation techniques resulted in reduced OAR
doses with the desired D90 coverage of the HR-CTV achieved.The graphbelow compares the D2cc values for the sigmoid against the HR-CTV D90
coverage for standard and optimised treatment plans. The tolerance doseline indicates the dose, which if repeated for all three fractions, is considered
to be tolerable.

It can be seen that the maximum D2cc and the range of D2cc for the sigmoid have both been reduced by the optimisation process. Similar results
are observed for the bladder. The D2cc results for the rectum were below thetolerance dose in all but one plan for both the optimised and standard plans.
Conclusions: Individual optimisation of treatment plans per fraction is required for all patients to account for differences in applicator position, organ
at risk location and tumour response/position. MR imaging has facilitatedplan optimisation which it is hoped will reduce BT associated toxicities whist
still achieving good tumour control. Optimisation has been shown to limit the
maximum D2cc observed compared to the use of standard plans. The limiting OAR during dose optimisation have been the bladder and sigmoid, while
the rectal dose has rarely been a cause for concern.

integrate FDG-PET/CT into the brachytherapy treatment planning in cervix
cancer represents a challenging issue.
660 poster
PRELIMINARYRESULTSOF
MRI-BASED
IMAGE-GUIDED
BRACHYTHERAPY FOR CERVIX CANCER – THE ADDENBROOKE’S
EXPERIENCE
D. Gregory1 , L. T. Tan1 , C. Coles1 , S. Brooke2 , D. Whitney2
1

A DDENBROOKE ’ S H OSPITAL, Department of Oncology, Cambridge, United
Kingdom
A DDENBROOKE ’ S H OSPITAL, Department of Medical Physics, Cambridge,
United Kingdom
2

Purpose: The preliminary evaluation of the efficacy of preoperative highdose-rate (HDR) brachytherapy (BT) measured by the rate of pathologic complete remission (pCR) in cervical cancer patients enrolled on a prospective,
randomized, multicentric study.
Materials: Between May 2005 and December 2008, one hundred operable
cervical cancer patients of FIGO stage I/A2 (n=4), I/B1 (n=51), I/B2 (n=19),
IIA (n=17), and proximal II/B (n=9) were randomized: in arm "A" (n=50) patients received 2x8 Gy preoperative intracavitary HDR BT, in arm "B" (n=50)
no preoperative treatment was given. In both arms patients underwent radical Wertheim (Piver 3) hysterectomy. The rate of pCR according to treatment
arms was determined by histopathological examination of the surgical specimens.
Results: 41 (82%) and 42 (84%) patients underwent the planned radical hysterectomy in arm "A" and B", respectively. The pCR rate was 26.8% (11/41)
after preoperative HDR BT, while it was only 7.1% (3/42) with surgery alone(p=0.0204).
Conclusions: Preoperative HDR BT significantly increases the rate of pCR
in patients with operable cervical cancer. The possible impact of pCR on theultimate local tumor control and survival can be established after a longer
follow-up period.
659 poster
PET/CT GUIDED BRACHYTHERAPY USING RING APPLICATORIN CERVIX CANCER. A FEASIBILITY STUDY AND DOSIMETRICCOMPARISON.
I. Rodriguez1 , C. Huerga2 , E. Corredoira2 , A. Córdoba1 , S. Elías1 , C.
Huertas2 , A. Serrada2 , A. Mañas1
1
H OSPITAL U NIVERSITARIO L A PAZ, Department of Radiation Oncology,
Madrid, Spain
2
H OSPITAL U NIVERSITARIO L A PAZ, Department of Medical Physics andRadiation Safety, Madrid, Spain
Purpose: Brachytherapy plays a relevant role to improve local control
in cervix cancer. In the three-dimensional (3D) era, based adaptative
brachytherapy has been reported with computed tomography (CT), magnetic
resonance imaging (MRI) and more recently with PET-CT using [18 F]-fluorurodeoxy-D-glucose (FDG-PET/CT). The latter’s advantage is that it has shown
functional and structural details in the same setting. This fact and an easier access to FDG-PET/CT at our institution have enabled the conduct of
this study. The objectives are, first, to evaluate the feasibility of using FDGPET/CT as a tool of target, critical organs and applicator delineation for intracavitary cervix cancer treatment planning, using a segmentation method withthreshold image intensity established at a certain percentage of the peak tumor intensity. Secondly, it is meant to analyze and compare the dosimetricresults of using a ring applicator in a treatment planning of 3D volumetric andfunctional image FDG-PET/CT versus a CT without FDG-PET for which theapplicator works as a reference.
Materials: The acquisitions were carried out in a hybrid PET/CT Discovery
LS, General Electric using the standard protocol. The CT image was used for
applicator reconstruction and organs at risk (OAR) delineation. PET imaging
was used to define target volume. In order to obtain segmentation thresholdfor our device, measurements were carried out on phantom with six hot inserts and distinct backgrounds, and a threshold of 37% of maximum activity
was used. Two types of optimization were performed and afterwards compared: the first one, based on the applicator and regularly used at our hospital, is outlined with a margin of 5 mm to be covered by the 100% isodose.
The second one is based on the PET defined volume. In both cases, the OAR
are contoured and optimized imposing restrictions of 2cc of the bladder andrectum as GEC-ESTRO recommended. This study will include 10 patients;
there are preliminary results for two of them.
Results: FDG-PET/CT for brachytherapy in cervix cancer is feasible, provides a reliable estimate of the cervical cancer volume and also a 3D spatial relationship of the tumor to the tandem and ring applicator, integrating
morphological and functional images. FDG-PET/CT not only localizes anddefines the extent of the cervical tumor, but also provides information about
the spatial orientation of the tumor as well as the bladder and rectum, withrespect to the ring applicator.
Conclusions: Using FDG-PET/CT as an image-based 3D brachytherapy
treatment planning may provide necessary information to optimize the delivered dose by allowing delineation of target volumes for quantifying target
dose coverage, and also provide similar information to critical structures. To

Purpose: We report our early experience of MRI-based image-guided
brachytherapy (IGBT) for cervix cancer using the tandem-ring applicator +/interstitial needles.
Materials: 29 patients were treated between January 2009 and June 2010.
The median age was 43 (range 31-83). The FIGO stage distribution was I =10, II = 13, III = 5 and IVa = 1. 8 patients had involved pelvic nodes and 2
had involved paraaortic nodes. Patients received external beam radiotherapy(45-50.4 Gy in 25-28 fractions) to the pelvis +/- para-aortic nodes with weekly
cisplatin chemotherapy (median number of cycles = 5). This was followed by
4 fractions of HDR BT over 3-8 days in 1 or 2 insertions. Interstitial needles
were added if there was residual parametrial disease at the time of BT. For
each insertion, a planning MRI was obtained on day 1 with the BT applicators in situ. The high risk clinical target volume (HR-CTV) was contoured on
the MRI images and was used to plan all subsequent fractions for that insertion. Planning CTs were obtained on each day of treatment and were used
for contouring the organs at risk (OAR). Individualised dosimetry plans werecreated for each day of treatment and were manually optimised to meet thetarget dose (85 Gy10 to D90 of HR-CTV) and OAR constraints (D2cc rectumand sigmoid = 75 Gy3, D2cc bladder = 90 Gy3).
Results: The median follow-up for surviving patients was 14 months (range
5-23). The 2-year actuarial survival was 96%. One patient with Stage 3b
disease died of metastatic disease 8 months after completion of RT. There
were no local recurrences. 22 patients received intracavitary BT alone. The
median doses for these patients were point A = 78 Gy (range 56-84), D90= 110 Gy10 (range 76-146), D2cc rectum = 64 Gy3 (range 51-75), D2cc
sigmoid = 69 Gy3 (range 47-77), D2cc bladder = 77 Gy3 (range 60-92). 7
patients were treated with intracavitary + interstitial BT. Their median doses
were point A = 84 Gy (range 58-89), D90 = 100 Gy10 (range 88-114), D2cc
rectum = 72 Gy3 (range 69-84), D2cc sigmoid = 71 Gy3 (range 53-77), D2cc
bladder = 83 Gy3 (range 65-104). 111 fractions were delivered and individual
dose adaptation was performed in 87.
Conclusions: Implementation of MRI-based IGBT has resulted in higher
doses to point A and D90 of the HR-CTV and lower D2cc rectum, sigmoid
and bladder compared to a previous cohort treated with CT-based IGBT. Early
results suggest that this has resulted in improved survival and local control,
but longer follow up is required to confirm this.
661 poster
QUALITY ASSURANCE: TOTAL REFERENCE AIR KERMA(TRAK), IRRADIATION TIMES AND TRANSIT TIMES IN CERVIX
BRACHYTHERAPY.
O. Oyekunle1 , B. Akinlade1

S 267

increased just by the same factor as corresponding values of source activity
had decreased, with respect to initial activity at first fractions. While transit
times are excluded in irradiation times, results showed that the former andconsequently calculated transit doses are apparently independent of fractional doses. Transit times for gynesource 3-channel treatments range from39.02 s to 58.40 s with a mean of 45.40 s ± 1.96 s. These translated intotransit doses of 0.156 Gy and 0.225 Gy respectively with a mean of 0.18 Gy± 0.009 Gy. Consequently, patients’ additional radiation doses range from
0.51 Gy to 0.59 Gy with an individual average of 0.54 Gy ± 0.018 Gy.
Conclusions: Evidently, TRAK is directly related to HDR fractional dose,and is a good parameter to compare brachytherapy treatment plans independent of source activity. Since patients’ additional dose depend to a larger
extent on transit time, constant efforts should be made to keep guide tubes
without bends when connected with afterloader and applicators. Further investigations of observed indefinite variation in transit time are required. It
is recommended that transit dose corrections be made for remote controlled
afterloading units.
662 poster
RADICAL INTERSTITIAL HDR BRACHYTHERAPY IN TREATMENT
OF RECURRENT VULVAR CANCER – A CASE STUDY
S. Kellas-Sleczka1 , B. Bialas1 , M. Fijalkowski1 , M. Szlag2 , A. Cholewka2
1
C ENTRE OF O NCOLOGY - I NSTITUTE MSC G LIWICE, Department of
Brachytherapy, Gliwice, Poland
2
C ENTRE OF O NCOLOGY - I NSTITUTE MSC G LIWICE, Department ofRadiotherapy and Brachytherapy Planning, Gliwice, Poland
Purpose: To present and assess tolerance and efficacy of radical interstitial
HDR BT for elderly patient in post operated second locally recurrent vulva
cancer.
Materials: Case Report80 year woman with G1 vulvar squamos cell carcinoma, localized on left labia majora, underwent vulvectomy and three months
later an inguinal lymphadectomy because of metastases to left ILN.
Results: 5 years after surgery tumour of 2 cm was observed on the left side of
the vulvectomy scar. Patient underwent radical treatment with interstitial HDR
brachytherapy alone to the total dose of 32 Gy in 3.2 Gy fractions scheduled
twice a day with 6 hours break. No tumour excision was performed before
irradiation. Three flexible catheters were implanted under local anaesthesia.
Reference dose was prescribed 5 mm from the central axis of the catheter.
Two fluoroscopic images were taken for planning purpose, immediately after implantation. Treatment plan was calculated with Plato system (NucletronB.V.) based on the reconstructed implant. Treatment was well tolerated. Although, five weeks after HDR-IBT the patient complained of an itching andburning in uro-genital area. There was also a 2cm focus of epitheliolysis intreated region, but it was healed in six weeks of follow up.In February 2010
(five years after brachytherapy), second recurrence of the tumour was observed on right side of a vulvectomy scar and in area of posterior fourchette.
The area of previous BT was free from disease. The patient underwent second definitive HDR-IBT scheduled and prepared as previously. The total dosewas 31.5 Gy delivered in 3.5 Gy fractions. At the first days of HDR-IBT andabout two weeks after the catheter removal the patient reported itching andslight pain because of superficial epitheliolysis which was healed in eightweeks. The patient is still under periodical controls. Till now, there is noevidence of recurrence.
Conclusions: Case analysis demonstrates that for vulva carcinoma radical
interstitial HDR BT seems to be an effective method, safely administered forelderly patient even in second locally recurrences.

1

U NIVERSITY C OLLEGE H OSPITAL, Department of Radiotherapy, Ibadan,
Nigeria

Purpose: Malignancy of the cervix is the primary indication for brachytherapy.
Effective quality assurance demands that issues that often prevent correct delivery of prescribed doses be addressed particularly in high dose rate (HDR)
brachytherapy. This study investigates total reference air kerma (TRAK), irradiation times and transit times in HDR intracavitary brachytherapy as a meansof controlling errors; and advises on what to check to achieve quality in treatment delivery.
Materials: A total of 165 HDR fractions involving 55 cervix cancer patientstreated with cobalt-60 gynesource afterloader unit and HDRplus planningsoftware from March to November, 2010; at the Department of Radiotherapy,
University College Hospital (UCH), Ibadan, Nigeria; were entered into thisstudy. In all treatments, patients ’additional radiation doses were calculated
from activity of the source at the instant of treatment as well as the corresponding transit times. TRAK, irradiation times, transit times and calculatedtransit doses were analyzed to understand how source decay is handled andenhance quality assurance vis-is dosimetry. Point ’A’prescribed doses of 15
Gy, 18 Gy and 21 Gy in 3 fractions were meted out to 36, 4 and 13 patients
respectively. Fractional doses to the two other patients were 4.5 Gy and 8 Gy.
Results: In 108 applications of 5 Gy, TRAK values range from 0.173 cGy.m2
to 0.457 cGy.m2 , 12 applications of 6 Gy had its values ranging from 0.362
cGy.m2 to 0.490 cGy.m2 while 39 fractions of 7 Gy showed least and peak
TRAK of 0.399 cGy.m2 and 0.533 cGy.m2 respectively. With one treatment
plan per patient, irradiation times for the 2nd and 3rd brachytherapy fractions

663 poster
REDUCTION OF RECTAL, SIGMOID AND BLADDER SIDE EFFECTS IN CERVICAL CANCER PATIENTS TREATED WITH 3D HDR
BRACHYTHERAPY
P. Pedicini1 , G. Califano1 , R. Caivano1 , G. Castaldo2 , F. Alba2 , V. Fusco2
1
I.R.C.C.S.- C.R.O.B., Medical Physics, Rionero in Vulture, Italy
2
I.R.C.C.S.- C.R.O.B., Radiation Therapy, Rionero in Vulture, Italy
Purpose: To increase the biological effectiveness of high-dose-ratebrachytherapy (HDR-BRT) in patients with gynecological cancer (GC), many
schemes of dose-fractionation were tested using a biological equivalent dosevolume histogram (BE-DVH) for plan analysis and as tool for the assessment
and choice of fractionation biologically most effective.
Materials: CT datasets for 22 women with GC were retrospectively selected.For all patients external beam radiotherapy (EBRT) was planned withtotal dose of 45Gy in fractions of 1,8Gy daily. Afterwards we planned by
3D HDR-BRT the boost of dose with a dose of 40Gy EQD2 (2Gy/fraction
and a/b=10) on 100% of GTV to reach a total dose of 85Gy EQD2. The
dose prescribed on the boost area, with the same relative dose distribution,
was shared by many fractionation schemes with the equal BED on the neoplastic target (7x4,5Gy, 6x5,2Gy, 5x6Gy, 4x7Gy, 3x8,5Gy, 2x11Gy) in orderto evaluate where we got lower toxicity for rectum, sigmoid and urinal bladder. This assessment was made by transformation of the DVH in BE-DVH

S 268B RACHYTHERAPY: H EAD N ECKB RACHYTHERAPY: G YNAECOLOGY

which is obtained from new index called "Toxicity Index", defined for each
OAR by linear quadratic model with condition of equal radiobiological effecton the target volume. BE-DVH can provide better choices for the kind ofdose fractionation that determines major benefits especially considering adequately sub-volumes of interest for each organ treated (10cc, 2cc, 1cc and 0.1cc).With this aim, from the DVHs we calculated the averages of D10cc, D2cc,
D1cc and D0.1cc and afterward from BE-DVH we calculated the equivalentdoses for each OAR (a/b=3) chancing the dose fractionation. The comparative analysis was made using 4x7Gy as reference fractionation and comparing the average of doses with correspondent tolerance doses reported in
Gyn GEC ESTRO working group recommendation (TD2cc=90Gy EQD2 forbladder, TD2cc=70Gy EQD2 for rectum, TD2cc=70Gy EQD2 for sigmoid).
Results: Mean value differences of equivalent dose between each fractionation and the reference fractionation, are shown in table as percentage. Positive values indicate a reduction in toxicity whereas negative values indicate
an increase in toxicity. The data show that with a decreased dose per fraction we have a reduction of toxicity more and more important. Converselywith an increased dose per fraction there is an increase of toxicity. However,the best compromise between reduced toxicity and reduced number of fractions (for the compliance of the patient) seems to be related to the reference
fractionation 7x4Gy or with 6x5Gy.

Conclusions: The BE-DVH allows to choose the best dose fractionation invaginal vault HDR-BRT treatments in patients with GC.
664 poster
RESULTS OF EXCLUSIVE ADJUVANT VAGINAL BRACHYTHERAPYIN INTERMEDIATE-RISK ENDOMETRIAL CANCER
O. Coza1 2 , S. Gavris1 , C. Ordeanu1 , M. Bako1 , A. Irimie3 4 , D. Eniu3 4 , A.
Rancea3 4 , S. Hica3 , D. Coza5
1
I NSTITUTE OF O NCOLOGY “I.C HIRICU ŢĂ ”, Brachytherapy Department,
Cluj-Napoca, Romania
2
U NIVERSITY OF M EDICINE AND P HARMACY C LUJ -N APOCA, Radiation
Oncology, Cluj-Napoca, Romania
3
I NSTITUTE OF O NCOLOGY “I.C HIRICU ŢĂ ”, Surgical Oncology, Cluj-Napoca,
Romania
4
U NIVERSITY OF M EDICINE AND P HARMACY C LUJ -N APOCA, Surgical
Oncology, Cluj-Napoca, Romania
5
I NSTITUTE OF O NCOLOGY “I.C HIRICU ŢĂ ”, Cancer Register, Cluj-Napoca,
Romania
Purpose: this is a retrospective nonrandomized study with the aim to evaluate adjuvant vaginal brachytherapy (VBT) efficiency in the intermediate-risk
endometrial cancer.
Materials: the study includes 79 patients with stage I-IIA (FIGO 1998) endometrial cancer. The median patients age was 58 (42-78) years. All patientswere initially submitted to radical surgery. After a median postoperative interval of 52 days VBT was performed: an endocavitary vaginal cilinder wasinserted 2 times per week, at 72 hours interval, for a total dose deliveredin high-dose rate (HDR) regimen of 28 Gy/ 4 fractions. The dose was prescribed at 5 mm. from the cilinder surface. The total treatment time was 10days. Median follow-up was 23 months (6-48).
Results: Local vaginal relapse ocurred in 4 patients (5%). Another two patients developed distant hematogenous metastases (lung and liver), both ofthem with agressive histology (clear cell carcinoma). Late vaginal toxicity wasobserved in 6 patients: 1 G3 and 5 G1 (CTCAE v 3.0).
Conclusions: In stage I-IIA endometrial cancer VBT is an effective treatment method with an acceptable rate of late toxicity. Adjuvant VBT can be
performed on an outpatient basis with a relatively short total treatment time.
665 poster
TREATMENT PLANNING FOR HDR BRACHYTHERAPY OF CERVIXCANCER BASED ON TOTAL DOSE CONSTRAINTS
Y. Bahadur1 , C. Constantinescu2 , A. Hassouna2 , M. Ezzat2
1
K ING A BDULAZIZ U NIVERSITY H OSPITAL, Radiology, Jeddah, Saudi Arabia
2
K ING FAISAL S PECIALIST H OSPITAL, Oncology, Jeddah, Saudi Arabia

Purpose: In order to apply the recommendation of the GYN GEC-ESTRO
Working Group in our routine clinical practice, we compare the 3D inverse
planning optimization versus conventional treatment plan (point A planning
method) for cervical carcinoma, and evaluate the improvement of DVH parameters when applying CT-based image guided brachytherapy.
Materials: We are reporting the analyzed data of 10 patients with cervix cancer treated with external beam radiotherapy to the whole pelvis (45 Gy in 25
fractions) followed by HDR brachytherapy (21 Gy in 3 fractions). For treatment
planning of HDR brachytherapy, the basic equations of the linear quadratic(LQ) model are used to calculate the physical dose for each brachytherapy
fraction needed to achieve a given total iso-effective dose for the whole treatment. For high risk (HR CTV) and intermediate risk (IR CTV) clinical target
volumes, the dose that covers 100% and 90% of the volume (D100, D90) areevaluated. For organs at risk (OARs), the mean doses to the most irradiated1 cm3 , 2 cm3 , and 5 cm3 (D1cc, D2cc, D5cc) are evaluated.
Results: In conventional plans, the HR CTV was well covered in only 15/30
and the IR CTV in 7/30 of the brachytherapy implants, while DVH constraints
of OARs bladder and rectum were respected in 28/30 and respectively 14/30
of implants. After optimization, the HR CTV and IR CTV DVH constraints
were respected in all the implants, and the bladder and rectum DVH constraints were respected in 25/30 and respectively 17/30 of cases. In conventional plans all DVH constraints were simultaneously respected in only 1/30of the brachytherapy implants, as compared to 16/30 brachytherapy implants
in optimized plans. Although the dose was in general increased, the recommendation of the GYN GEC-ESTRO Working Group for a cumulative D90 of
HR CTV EQD2 ≥ 85 Gy was not fulfilled.
Conclusions: Point A is a poor surrogate of target dose in an individual
patient, but may provide a reasonable estimate of the average HR CTV D90
in a patient population. Overall discrepancies between point doses and DVH
parameters support the use of 3D image-based inverse planning and useof DVH parameters for better assessment of both target and OARs dose inbrachytherapy of cervical cancer.

667 poster

669 poster

VALUE OF MRI IN THE DETERMINATION OF HR-CTV AND OAR IN
3D CERVIX CANCER: COMPARATIVE STUDY WITH CT SCAN.
I. David1
1
I NSTITUT C LAUDIUS R EGAUD, Department of Radiation Oncology,
Toulouse, France

WHOLE PELVIC TOMOTHERAPY FOR LOCALLY ADVANCEDCERVICAL CANCER WITH PARAMETRIUM SIB FOLLOWED BY HDR
BRACHYTHERAPY
S. Garelli1 , R. Bampi1 , S. Barra2 , F. Giannelli2 , F. Vallerga3 , G. Taccini1
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Medical Physics,
Genova, Italy
2
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Radiation Oncology,
Genova, Italy
3
U NIVERSITÀ DI G ENOVA, Radiation Oncology, Genova, Italy

Purpose: To evaluate the value of magnetic resonance imaging (MRI) in comparison with computed tomography (CT) in the determination of high risk CTV(HR-CTV) and organ at risk (OAR) in 3D gynaecologic PDR brachytherapy.
Materials: Twelve patients with primary locally IBI-IV cervical carcinomas
were treated with PDR brachytherapy using Fletcher-Suit applicator suitablefor MRI, after concomitant pelvic chemo-radiotherapy. Both MRI and CT scanwere realized the day of application.Target and OAR volumes, based on clinical exam and diagnosis MRI, were delineated on MRI and CT using the GYN
GEC-ESTRO recommendations, by one resident, one assistant and one senior radiation oncologist. CT and MRI contours were realized at different
period of time to avoid real time inter comparison.
Results: The HR-CTV volume measured on MRI was significantly lower thanthat measured on CT (p=0.034) for the practitioners all together, and particularly for the resident (p=0.0037)There were no volume difference for OAR,
excepted for the sigmoid (p=0.0029)The coefficient of correlation between
practitioners was 88% for MRI versus 80% for CT scan for the HR-CTV volume, and 79.3% versus 38.7% for the sigmoid volume.
Conclusions: MRI allows to improve the reproducibility of contouring between different practitioners in the determination of VHR, for cervical carcinoma.Volumes measured on MRI were significantly lower than that measured
on CT scan, in particular for the practitioners experimented.The MRI has tobecome the standard in the determination of HR-CTV and OAR in 3D gynaecologic brachytherapy

666 poster

668 poster

UTRECHT APPLICATOR RECONSTRUCTION IN MRI-BASEDCERVIX GYNAECOLOGICAL BRACHYTHERAPY
J. Pérez-Calatayud1 2 , V. Carmona1 , F. Lliso1 , M. D. C. Pujades

VULVOVAGINAL INTERSTITIAL HDR BRACHYTHERAPY IN PRIMARY AND RECURRENT GYNAECOLOGICAL MALIGNANCIES
P. De Ieso1 , V. M. Mullassery1 , R. Shrimali2 , G. Lowe1 , P. Hoskin1
1
M OUNT V ERNON H OSPITAL, Northwood Middlesex, United Kingdom
2
T HE C HRISTIE NHS F OUNDATION T RUST, Manchester, United Kingdom

Claumarchirant1 , C. Camacho1 , F. Ballester3
1
H OSPITAL U NIVERSITARIO L A F E, Radiation Therapy Department,
Valencia, Spain
2
ITIC, H OSPITAL C LÍNICA B ENIDORM, Radiation Therapy Department,
Benidorm, Spain
3
U NIVERSITY OF VALENCIA -IFIC, Radiation Therapy Department, Valencia(Paterna), Spain
Purpose: GYN GEC-ESTRO recommendations stated the convenience ofperforming a 3D magnetic resonance imaging (MRI)based treatment planning for brachytherapy in cervical cancer. The aim of combining intracavitary/interstitial brachytherapy is to tailor the dose of irradiation to the anatomyof the patient with a better coverage of the high risk CTV and intermediate risk
CTV, eg. lessions that involve different levels of parametrium. To this purpose
several applicators have been developed, among them the Utrecht applicatorconsisting of a tandem plus colpostats with plastic needles inserted.Dummycatheters for tandem and colpostats reconstruction have been developed byPerez-Calatayud et al. (R&O 2009) but there are not dummies for the needles.The objective of this work is to describe our experience in the MRI-based
reconstruction of the Utrecht applicators.
Materials: At our department combined interstitial/intracavitary Utrecht applicators are used in cervical cancer HDR brachytherapy applications consisting in 4 fractions of 7 Gy, after 45 -50 Gy of 3DCRT. For each application
MR scans with applicator in situ are made. Two different MRI modalities havebeen used to acquire the images that are imported in Oncentra MasterPlan (V3.2, Nucletron) treatment planning system to calculate the dose distribution.a)
In a first stage the sequence of images were acquired in a GEMS SIGMA
EXCITE MRI Unit with strength of 1.5T. Details of the acquisition and thereconstruction of the intracavitary catheters have been described in PerezCalatayud et al. (R&O 2009).b) Lately the acquisition is done in a Siemens
TrioTim MRI unit with a field strength of 3T, using a 3D sequence based ona set of acquired coronal images, dedicated to the geometric reconstructionof the catheters, in conjunction with transverse images that are intended tothe definition of the volumes of interest by the radiation oncologist and theradiologist. Regarding the reconstruction of the interstitial needles, the information of the retraction of the applicator scale is set on Oncentra MasterPlan
with the help of the measuring distance tools on the paracoronal/parasagitalreconstructed planes that contain the needle. At the same time the black holecorresponding to the needle position in the transverse view is used.
Results: Several examples are presented to illustrate the fast and efficient
process described here, which allows the reconstruction of the Utrecht applicators without any dummy phantom.Great difficulties were found in the interstitial needles reconstruction with the 1.5T scans whereas with the 3T technique the image quality has been improved.The reconstruction has been alsoenhanced by the 3D acquisition mode.
Conclusions: A feasible method for the Utrecht applicator reconstruction
based on 3T MRI data acquisition has been established.

S 269

Purpose: Evaluation of interstitial high dose rate (HDR) brachytherapy to
the vulvovaginal region both alone and in combination with external beam
radiotherapy (EBRT) for primary or recurrent gynaecological malignancy.
Materials: From 1998 to 2009, 37 women with a mean age of 68 years weretreated with HDR perineal interstitial brachytherapy. Fifteen patients (40.5%)
were treated for primary disease while 22 (59.5%) patients were treated forrecurrent disease. Median time to local recurrence was 31 months (2 312
months). Primary sites included endometrium (12), vulva (11), vagina (10),vulvo-vaginal (1), cervix (1) and bladder (2). Thirty one patients (83.7%) in
this series were treated with radical intent while 6 (16.3%) were treated withpalliative intent. Radically treated patients received between 45 to 60 Gy(median 45Gy) of EBRT. The median number of days from EBRT to HDR
boost was 5 (1 35 days). The HDR brachytherapy doses ranged from 11Gy
in 2 fractions to 38Gy in 5 fractions (dose per fraction varied from 4 - 8.5Gy)
and fractions were given at least 6-8 hours apart.
Results: Eight of the 31 patients (26%) treated with radical intent relapsed
locally. Eleven of 37 patients (30%) treated with either radical or palliative
intent recurred locally. The 2 and 5 year local PFS was 74% and 63.4% respectively. The total PFS which includes local, locoregional /nodal and distantrecurrence at 2 and 5 years was 73.6% and 45.6% respectively. With a meanfollow up of 27 months (3.88-111.9 months) the median survival for the patientgroup was 16.57 months with a 2 and 5 year OS of 47.7% and 36.4% respectively.Acute grade 3 toxicity was seen in 13 (35%) of the 37 patients (skin -10,urinary 2, genital 2, gastrointestinal -0). No acute grade 4 toxicities wereseen. A total of 10 of the 37 patients (27%) developed late grade 3 toxicities.
Five of the 22 patients (22%) treated for recurrent disease with radical intent
developed grade 3 toxicity (skin -4, urinary -2, genital -1, radiation induced
fracture of acetabulum - 1 gastrointestinal -0) while 1 of the 6 patients treatedwith palliative intent had grade 3 toxicity (skin 1). No late grade 4 toxicities
were seen.
Conclusions: This retrospective series suggests interstitial perineal HDR
brachytherapy is a safe and effective treatment option for primary or locallyrecurrent gynaecological malignancies. It is a valuable option in patients who
have received previous EBRT to the pelvis, achieving good local control withacceptable late treatment related side effects.

Purpose: To evaluate the treatment plan with helical tomotherapy (HT) for
whole pelvic irradiation with simultaneously integrated boost (SIB) for locallyadvanced cervical cancer followed by high dose rate (HDR) intracavitarybrachytherapy.
Materials: From May to December 2010 5 patients with FIGO II-III uterine cervix cancer received concurrent chemoradiation with pelvic helical tomotherapy (Hi-Art) irradiation including SIB to parametrium and involved at
diagnosis lymph nodes followed by HDR intracavitary brachytherapy.Wholepelvic external beam irradiation was 45 Gy and a 57.50 Gy SIB was deliveredin 25 fractions. During external beam irradiation all patients were treatedwith Cisplatin 40-50 mg/m2 intravenously.The HDR intracavitary brachytherapy total dose was 24 Gy/4 fractions twice a week. Total treatment duration
was seven weeks.For external radiotherapy, delineation of target volumes
was according to ICRU Report 50 and 62. The OARs bladder, rectum, intestine and femoral heads were contoured.For brachytherapy all patients atevery treatment session underwent MRI scan. HR and IR CTVs were delineated according to the Recommendations from GYN GEC-ESTRO Working
Group. OARs bladder, rectum and intestine were contoured.For every helicaltomotherapy plan a standard 3D plan and a conventional step & shoot IMRT
were compared.Dose-volume histograms of the PTVs and the critical normal
structures were analyzed. For PTVs we evaluated V95, D5 and D95. The
conformal index and the uniformity index have been used to evaluate plans;
for critical organs we examined different doses. We also evaluated the possibility to have DVH for PTVs and OAR for the external plan summed to theintracavitary plans.
Results: For what concerns external radiation plans we found that helical tomotherapy provides better sparing of OARs in terms of mean dose and otherparameters for bladder, rectum, intestine and femoral heads. It provides also
better conformity and uniformity for both PTVs. For whole pelvic irradiation
we have C.I.mean (1.39 ± 0.04), U.I.mean (1.13 ± 0.04). For SIB volume
we have C.I.mean (0.99 ± 0.04), U.I.mean (1.07 ± 0.02).Acute toxicity oftreatment was scored in according to RTOG scoring system, one grade 2
for diarrhea and leucopoenia was noted during CT/RT. Nobody interrupted
treatment radiation.
Conclusions: In our preliminary results we can conclude that helical tomotherapy provides a very good sparing of OARs with a good conformity
and uniformity for PTVs also with a SIB. The SIB permits to have a boost
external dose delivered in parametrium and lymph nodes to compensate thedrop dose with intrauterine irradiation. Our external radiotherapy fractionation
permits also a seven weeks whole treatment duration.

Brachytherapy: Head Neck
670 poster
A CASE OF ORBITAL INTRAOPERATIVE BRACHYTHERAPY.
C. Gutiérrez Miguélez1 , E. Martinez Perez1 , J. pera1 , F. Mascaro1 , O.
Picon1 , S. Moreno Amagro1 , J. M. Piulats1 , F. Gonzalez Delgado1 , M. N.
Gonzalez Imhof1 , B. Londres1 , F. Guedea1
1
I NSTITUT C ATALÀ D ’O NCOLOGIA, Radiation Oncology Dept. and Center
for Molecular Imaging and Experimental Radiotherapy, L’Hospitalet de
Llobregat, Spain
Purpose: To describe an unusual localization of intraoperative brachytherapy.
A 23-year old patient was diagnosed with orbital sarcoma. Previous medical
history: when the patient was 3 months old, he was diagnosed with bilateralretinoblastoma. He underwent left enucleation followed by bilateral orbital
irradiation. He was free of disease, but as a sequelae he presents cranial
and facial bone hypoplasia. In May 2009 he noted an inflammation in his rightinferior eyelid. In September 2009 a mass was found on MRI and removed.
The pathological finding was " radiation-induced fusocelular sarcoma". The
patient refused enucleation of his only eye. In September 2010 a relapse
was diagnosed byclinical examination and confirmed with MRI. As the patient
continues to refuse radical surgery, we propose conservative treatment withlocal extirpation and intraoperative brachytherapy.
Materials: After macroscopical removal of the tumor, 4 plastic tubes in one
plane were inserted into the tumoral bed, in the inferior and external part ofhis right orbita and his inferior eyelid. A CT scan was performed afterwards todefine the tumor bed, and the organs at risk: the optic nerve and the retina.

S 270B RACHYTHERAPY: M ISCELLANEOUS

B RACHYTHERAPY: M ISCELLANEOUS

Results: A total dose of 50 Gy with PDR at a rate dose of 0.7 Gy/h wasadministered to the surgical bed. There was no important acute toxicity. The
catheters were removed without problems and for the moment, the patient isalive and free of disease. The patient will need to be monitored for possible
late toxicity.
Conclusions: Conservative treatment of orbital tumors with surgery and intraoperative brachytherapy can be performed in certain circumstances if tumor removal is feasible. Col.laboration with surgeons is mandatory.
671 poster
SALVAGE HIGH-DOSE-RATE INTERSTITIAL BRACHYTHERAPY IN
RECURRRENT AND PREVIOUSLY IRRADIATED HEAD AND NECKCANCER.
L. Gutierrez Bayard1 , M. C. SALAS BUZON1 , M. E. Angulo Pain2 , E. Munive
Alvarez1 , E. Gonzalez Calvo1
H OSPITAL U NIVERSITARIO P UERTA DEL M AR, Oncology radiation departament, Cadiz, Spain
2
H OSPITAL U NIVERSITARIO P UERTA DEL M AR, Department of Radiophysics,
Cadiz, Spain
1

Purpose: Despite advances in the treatment of head and neck cancer (HNC),
15%-50% of patients will have their disease recur. For patients who present
with locally recurrent disease or a second primary tumor in a previously irradiated field, therapeutic options are limited. Surgical salvage as curative
intent resection is the preferred option for those with limited-volume disease.
Reirradiation with or without the addition of chemotherapy may hold promisefor long-term survival for selected patients.
Materials: High- dose- rate (HDR) brachytherapy can play an important rolein the salvage treatment of previously irradiated recurrent head and neck cancer. We report a 56-year old man diagnosed of tongue cancer, with recurrent
metastatic contralateral cervical node 1.5 years after radical treatment withsurgery and adjuvant external radiotherapy. He received multidisciplinary
treatment with chemotherapy, surgery and HDR interstitial brachytherapy.
Results: After 2.5 year of follow up, the patient is free of recurrence, his
performance status is zero, without pain, and toxicity according to the Radiation Therapy Oncology Group (RTOG) grading system and National Cancer
Institute common toxicity criteria (version 3.0) was grade I late soft tissues
fibrosis.
Conclusions: Re-irradiation with HDR brachytherapy is feasible in recurrent
HNC. The delayed toxicities seem to be decreased compared to conventional
external beam therapy. This technique offers dosimetric advantage, radiation
safety and patient comfort, with a good local control and acceptable morbidity. Multidisciplinary planned surgical resection followed by HDRBT, have obtained a good response in this high-risk patients. Treatment in recurrent headand neck cancer is a therapeutic challenge, but we think the multidisciplinary
cancer team has been very important in patient outcomes.

Brachytherapy: Miscellaneous
672 poster
ENDOBRONCHIAL BRACHYTHERAPY : A TREATMENT OPTIONWITH MINIMAL SIDE EFFECTS
S. Shadchehr1 , J. Pantano1 , T. Lo2 , C. Lamb1
1
L AHEY C LINIC, Pulmonary Medicine, Burlington, USA
2
L AHEY C LINIC, Radiation Oncology, Burlington, USA
Purpose: Limited treatment options exist for patients with locally recurrent
lung cancer and metastatic endobronchial tumors. Endobronchial brachytherapy (EBBT) remains a viable option to provide localized radiation to palliate
symptoms and reestablish airway patency with minimal side effects.
Materials: The radiation oncology database of patients treated with EBBT in
our institution from February 1996 to April 2009 was used for this study with
IRB approval. It was a retrospective chart review of 88 patients. Each patient record was analysed for presenting symptoms including cough, dyspnea,
chest pain, hemoptysis, pneumothorax, and respiratory failure necessitating
hospital admission before and after EBBT. Endobronchial brachytherapy was
typically delivered in 3 sessions of 6 to 7 Gy each, in weekly intervals.
Results: The incidence of catheter malposition was 25% in the right upper
lobe (RUL).A small percentage of procedure related side effects were notedin our cohort: 4.5%. One patient (2.5%) developed cough immediately after
the procedure. Three patients (3.8%) developed respiratory failure after theprocedure, necessitating transfer to a higher level of care for either increased
oxygen therapy or closer monitoring without endotracheal intubation. There
were no deaths as a result of treatment. There were no documented symptoms of shortness of breath, chest pain, hemoptysis, or pneumothorax documented related to EBBT.EBBT improved the following symptoms: hemoptysis(90.9%), respiratory failure (85.7%), cough (79.5%), chest pain (76.9%), andshortness of breath (73.2%).Survival was defined as days alive after EBBT.

Survival was evaluated and divided by pathological category into small cell
carcinoma, non-small cell carcinoma, and metastatic. Our data showed thatthe best survival was in the metastatic/other group (272 days), followed by
non-small cell carcinoma (122 days), and small cell carcinoma (112 days).
This result appears to parallel the nature history of the disease.
Conclusions: EBBT is a safe procedure with a low complication rate. Careful patient selection and modification of intended treatment in cases where
there is evidence of prior radiation-induced damage seem to have averted
significant treatment complications.EBBT in conjunction with other invasive
interventional procedures can be a good option for palliating symptoms fromendobronchial malignancies causing hemoptysis, cough, and shortness ofbreath.
673 poster
HDR BRACHYTHERAPY AS CONSERVATIVE TREATMENT FOR
EARLY LOWER RECTUM ADENOCARCINOMA
G. Kacso1 2 , S. A. Istrate3 , Z. Sparchez4 2 , A. Rancea5 2 , A. Irimie5 2
1
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Brachytherapy
Department, Cluj-Napoca, Romania
2
I ULIU H ATIEGANU M EDICAL U NIVERSITY, Cluj, Romania, Cluj, Romania
3
I NSTITUTE OF O NCOLOGY P ROF. D R . I. C HIRICUTA, Radiotherapy
Department, Cluj Napoca, Romania
4
3 RD M EDICAL C LINIC, Gastroenterology, Cluj-Napoca, Romania
5
O NCOLOGY I NSTITUTE "P ROF.D R . I ON C HIRICUTA ", Surgery, Cluj-Napoca,
Romania
Purpose: Efficacy and toxicity analysis of high dose-rate brachytherapy(HDR-BT) adjuvant after endoanal excision for early stage lower rectum adenocarcinoma (ELRAK).
Materials: In our institution, since 2005, all patients with T1NoMo ELRAK involving less than 50 % of the rectal circumference and who refused amputation of the rectum were offered adjuvant HDR-BT after endoanal full-thickness
excision, provided it was pT1-2 with negative margins (Ro). From June 2005
to June 2010, only 10 patients were included in this prospective study. Ambulatory one weekly fraction Iridium 192 HDR-BT was delivered via endorectal
applicator (for elderly pT1 patients with contraindications for general anesthesia) or stainless equidistant parallel needles placed in the rectal wall throughthe Papillon type perineal template for all others. The dose prescription points
were 5 mm external to the cylinder surface or needles axis. The dose was 5 fr
of 6.5 Gy/fr for pT1, 6 fr of 7 Gy/fr for minimal pT2 (focal invasion limited to theinner muscle layer of the rectal wall). For frankly pT2 (external muscle layer
involvement), 3fr of 4Gy were added as a boost to 50Gy/25fr/ 5 wks externalbeam radiotherapy (EBRT). Local recurrence obviated salvage amputation.
Toxicity was recorded on CTC 3.0 criteria.
Results: Median age was 69 years [47- 85], 50 % being T1, 30 % minimal T2
and 20 % frankly T2. With a median follow-up of 28 months [6 to 65 months],
the local control was 100 %, 66 % and 50% for pT1, minimal and frankly
pT2, respectively. The sole recurrence for the minimal pT2R0 subgroup was
related to a close resection margin (0.2 mm). The overall 3 year local control
was 100% including the salvage surgery (2 patients). The maximum rectal
acute toxicity was G2, transient and there were no G2 or higher late toxicities.
Conclusions: Adjuvant HDR-BT after conservative full thickness endoanal
excision might be a reasonable alternative to amputation for lower rectum
pT1or minimal pT2 Ro cN0Mo adenocarcinoma. Patients having a deep muscle invasion or with resection margins less or equal to 0.2 mm need upfront
radical surgery, as dose escalade by BT boost to the EBRT can not palliate asuboptimal conservative surgery.
674 poster
INTERSTITIAL BRACHYTHERAPY FOR SOLITARY METASTATICLESIONS OF LUNG AND LIVER
D. N. Sharma1 , G. Rath1 , S. Thulkar2 , P. Julka1 , A. Gandhi1
1
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, Radiation Oncology,
NewDelhi, India
2
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, Radiology, NewDelhi, India
Purpose: To study the feasibility of interstitial brachytherapy (IBT) in patientswith solitary metastatic lesions of lung and liver, not suitable for surgery.
Materials: Twelve patients with solitary metastatic lesions in lung (9 patients)
or liver (3 patients), were enrolled in this study. The procedure of IBT was
carried out in CT scan room under local anesthesia. A single stainless steel
blind end needle for lesions up to 4 cm and two needles for lesions up to 6
cm in diameter were used. The needle was inserted percutaneously throughthe intercostal space into the center of lesion under the CT guidance. A single dose of 20 Gy with high dose rate (HDR) brachytherapy was prescribedat the periphery of lesion. The treatment was delivered on remote afterloading HDR brachytherapy unit in adjacent room and the needle was removed
immediately after treatment.
Results: There were 8 males and 4 females with a median age of 52 years.
The lesion size raged from 3.0-5.5 cm (median 4.0 cm). The average time
taken in IBT procedure was 50 minutes. No patient had acute severe proce-dure related complication (hemo/pneumothorax or hemoptysis) during perioperative period. CT scan at one month revealed complete regression (CR)of the lesion in 1 patient; and more than 50% regression (partial regression,PR) in 5 patients and minimal response in 2 patients. At 6 month follow up, 8
patients had complete ablation of the lesion. One patient developed jaundice
3 months after the procedure.
Conclusions: IBT with HDR is safe and feasible in the treatment of solitary
metastatic lesions of lung and liver.
675 poster
LOCAL CONTROL AND TOXICITY IN PATIENTS WITH SOFT TISSUESARCOMA TREATED IN COMBINATION WITH INTERSTITIAL
BRACHYTHERAPY AND EXTERNAL BEAM RADIOTHERAPYADJUVANT.
M. La Macchia12 , A. Galuppi2 , S. Medoro2 , L. Bordonaro2 , S. Cima2 , E.
Lombardo3 , I. Ammendolia2 , S. Cammelli2 , A. Ferraro4 , S. Ferrari5 , M.
Mercuri4 , E. Barbieri2
1
AT RE P, AGENZIA P ROVINCIALE PER LA P ROTONTERAPIA, Department ofRadiation Oncology, Trento, Italy
2
P OLICLINICO S. O RSOLA M ALPIGHI, Department of Radiation Oncology,
Bologna, Italy
3
P OLICLINICO S. O RSOLA M ALPIGHI, Department of Medical Physics andRadiation Safety, Bologna, Italy
4
I STITUTO O RTOPEDICO R IZZOLI, Department Of Orthopedic Surgery,
Bologna, Italy
5
I STITUTO O RTOPEDICO R IZZOLI, Department of oncology and medical
physics, Bologna, Italy
Purpose: The purpose of this study was to evaluate local control and complication rate after treatment of soft tissue sarcoma (STS) with surgery combined with pulsed-dose rate (PDR) interstitial brachytherapy (BRT) and external beam radiotherapy (EBRT).
Materials: Between January 2002 and December 2009, 251 patients withhistological proven STS, have had surgery at Rizzoli Orthopedic Institute(IOR) and BRT at Radiotherapy of Policlinico Sant’Orsola-Malpighi and subsequentially external-beam radiotherapy (EBRT). The mean age is 51 (range
9-86), 107 female (47%) and 144 male (53%). The areas most frequently
suffering from the disease were: the lower extremities in 161 patients (64%),
the upper extremities in 69 patients (27%). The remaining cases (9%) include
various locations of the disease mainly superficial trunk. The most frequent
histology was fusate cells sarcoma in 52 patients (21%), synovial sarcoma
in 36 patients (14%) and mixoid lipopsarcoma in 14 patients (6%). Patientswere divided into 3 groups depending on the type of surgery performed. The
first group of 105 patients (41%) underwent to excision of scar, the secondof 64 patients (25%) underwent to excision of local recurrence, and the thirdgroup of 62 patients (24%) received surgery in the first. All 251 patients were
performed to BRT after surgery. The median dose for the PDR-BRT is 20 Gy.
The EBRT after the surgery and BRT was performed: the median dose of
EBRT is 46 Gy.
Results: In our group of 251 patients, local control was opteined in 96% of
patients of first and second group and in 98 % in the third group.
Conclusions: Our study suggests a trend in favour of PDR-BRT boost plus
EBRT as a optimal adjuvant local strategy for STS. BRT resulted in an effective modality with a good cosmetic and functional results and acceptablereversible toxicity. The percentage of patients without local recurrence is 95%:
this result agrees with literature values.The main problem remains the occurrence of metastasis, expecially to the lung, that is the main reason of therapeutic failure.
676 poster
PERI-OPERATIVE HIGH-DOSE RATE BRACHYRTHERAPY IN THE
TREATMENT OF KELOIDS OF THE HEAD AND NECK AREA.
R. Hernanz de Lucas1 , A. Montero1 , A. Polo1 , E. Fernández Lizarbe1 ,A. Hervas Moron1 , S. Sancho García1 , R. Morera López1 , M. C. Vallejo
Ocaña1 , A. Ramos Aguerri1
1
R AMON Y C AJAL H OSPITAL, Department of Radiation Oncology, Madrid,
Spain
Purpose: Keloids are benign and proliferative growths of dermal collagen,usually resulting from excessive tissue response to trauma. Surgical resection remains as the mainstream of treatment, although recurrences are frequent. Post-operative radiotherapy has demonstrated to lessen local recurrences. We present our experience with peri-operative HDR brachytherapy inthe treatment of keloids.
Materials: From July 2009 to October 2010, 7 consecutive patients withkeloids were attended in our department. There were 6 males and 1 female,with a median age of 40 years (range 26 to 77 years).Three patients were
black and the remaining four were white. Keloids were located on the ear-lobe(6 patients) and the neck (1 patient). Peri-operative brachytherapy was performed leaving a 6F plastic catheter attached to the surgical bed along before
wound closure and extended at least 10 mm beyond both wound extremes.

S 271

Treatment was carried out by an HDR equipment containing a 192-iridium
radioactive source (Microselectron Nucletron BV, Veenendaal, the Netherlands). Dose-calculations were made according to the rules of the Paris
System and a total dose of 16-20 Gy in 4-5 fractions on two consecutive
days (median 16 Gy in 4 fractions) was prescribed at 5 mm depth from thecatheter. First fraction was administered within 90 minutes from surgical resection. Fractions 2 to 4 were separated at least 6 hours facilitating normal
tissue recovery.
Results: With a median follow-up of 7 months (range 2-17 months), all patients are free from keloid recurrence. Cosmetic result is considered as goodor excellent and the 7 patients, without having presented acute nor late toxicity attributable to brachytherapy procedure.
Conclusions: This study supports that surgical excision of keloids followed
by immediate peri-operative HDR brachytherapy is a reliable approach withgood results and few complications.
677 poster
PLAQUE BRACHTHEAPY EXPEIENCE IN DEVELOPING COUNTRIES: JORDAN AS AN EXAMPLE
L. Y. I. Mula-Hussain1 , S. Wadi-Ramahi1 , A. Al-Mousa1 , M. Mehyar2 , S.
Kharma2 , K. Rawashdeh2 , I. Nawaiseh2 , G. Abdeen3 , I. Sultan4 , I. J.
Jaradat1
1
K ING H USSEIN C ANCER C ENTER, Department of Radiation Oncology,
Amman, Jordan
2
K ING H USSEIN C ANCER C ENTER, Department of Surgery, Amman, Jordan
3
K ING H USSEIN C ANCER C ENTER, Department of Medicine, Amman,
Jordan4
K ING H USSEIN C ANCER C ENTER, Department of Pediatrics, Amman,
JordanPurpose: Ocular tumors (OT) are rare in general. Multi-modality approach"including the integration of Plaque Brachytherapy (PB)" for glob "with/without
vision" preservation showed dramatic improvement for OT care in developed
countries, however, this technique is hardly found in many developing countries. This abstract will highlights the three years experience of a single institute (King Hussein Cancer Center - KHCC) in Jordan as an example ofestablishing this technology in developing countries.
Materials: A descriptive review for the logistic and practical steps involvedin the establishment of PB at the KHCC in Jordan and its related practicalchallenges and preliminary clinical results.
Results: As part of the Ocular Oncology Program at KHCC, the preparatory
steps of PB were started in mid 2006. The assigned multi-disciplinary teamcollaborated with other advanced PB programs in developed countries (USA,Germany and Canada). Since Mar. 2008, the team did twelve proceduresfor different cases of OT "25% Retinoblastoma in children and 75% Ocular
Melanoma in adults", 75% were Jordanian and 25% were from neighboring
countries. Our preliminary results were encouraging (91% organ preservation/local control).
Conclusions: PB was successfully implemented at KHCC in around 18
months and this service can be applied easily in other developing countries.
This program served our national patients and those from neighboring countries. Close integration with other advanced centers and programs is mandatory for this implementation in order to safely and correctly transfer this technology from developed and developing nations. Our preliminary results wereencouraging and were similar to other programs worldwide.
678 posterQUOVADIS: A FAST AND ACCURATE TOOL FOR QA OF HDR
BRACHYTHERAPY SOURCE TRANSIT SPEED, DWELL POSITION
AND TIME OVER ALL THE SYSTEM CHANNELS
M. Carrara1 , G. Gambarini2 , M. Borroni1 , A. Cerrotta3 , C. Fallai3 , G.
Zonca1
1
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Medical Physics,
Milan, Italy
2
U NIVERSITÀ DEGLI S TUDI , IRCCS AND INFN, Department of Physics,
Milan, Italy
3
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Department ofRadiotherapy, Milan, Italy
Purpose: The likelihood that each individual treatment is administered consistently and that it accurately realizes the radiation oncologist’s clinical intent is maximized by developing a dedicated brachytherapy quality assurance(QA) program. Purpose of this program is to ensure that all devices required
for treatment planning and delivery continue to function as assumed by thetreatment delivery protocol.Aim of this study was to develop a system for thefast, objective and accurate QA of some non-dosimetric brachytherapy source
parameters recommended by the AAPM TG-56 protocol. To this aim, a tool
named QuoVadis composed of a measurement system and a dedicated software was developed, characterized and tested.
Materials: The hardware of QuoVadis consists basically of a fluorescentscreen and a high definition CCD camera. 18 catheters are placed under theS 272B RACHYTHERAPY: P HYSICSB RACHYTHERAPY: P HYSICS

screen in the CCD camera field of view and firmly hold in place. Whenever
the source is in the CCD field of view and the room light is turned off, a fluorescent halo due to the source radiation is clearly visible on the screen andrecorded by the camera. Source dwell position and time as well as source
transit speed are then deducted from that halo by means of an automatedsource position recognition algorithm. As results of the analysis, QuoVadis
returns the estimated source transit speed, measured dwell positions, measured dwell times, differences between measured and reference values andtheir comparison with tolerance values.In this study, brachytherapy irradiations were performed by means of a 18 channels Microselectron HDR remote
afterloading device. To validate QuoVadis, the inter-frames reproducibility of
the automated source position recognition algorithm was evaluated and QA
measurements were performed and compared to reference values of all the
18 channels.
Results: Mean and median differences of the location of a standing source
over 891 images were both of 0.02±0.01mm, respectively, resulting in a very
high reproducibility of the source dwell position recognition on each image
frame. The reported figure shows the planar distribution (in millimetres) of all
the obtained positions of the standing source.

5 patients were treated with a conformal plan (CP) CP used CT images to define the Gross Tumour Volume (GTV entire circumference of involved tumour
bearing region of the oesophagus). Margins of 2 to 3 cm were added superiorly and inferiorly by extending the volume of the GTV manually to define
the PTV. 8Gy was prescribed to the isodose providing the best PTV coverage. We compared the dosimetry of SP with CP retrospectively for the first 5
patients and prospectively for the last 5 patients.
Results: Mean V100 PTV (volume that received 100% of the prescribeddose) coverage for CP were 80.7% (range 53.6 - 96.9%) and 55.8% (range
22.1 - 79.1%) for SP. Mean V200 PTV ( mucosal dose) was 33.06% (range
23.04 42.36%) and 15.34% (range 6.43 24.31) for CP and SP respectively.Mean D90PTV (dose to 90% of the PTV) for the CP cohort was 6.65
Gy (range 3.72 9.6 Gy) when compared with SP = 4.55 Gy (range 1.83-6.9).
The improvement in the mean D90PTV in the CP cohort was 2.1Gy (range
1.06-3.19). The maximum value of dose to 0.1cc of cord (D0.1cc) were CP=
2.77Gy and SP=2.03Gy.No acute grade 3 or 4 toxicity was observed. 2 patients have required stents for local progression following brachytherapy.
Conclusions: This small series demonstrates the advantage of conformalplanning and is now routinely used in our centre.

Materials: The commissioning of the Brachytherapy module of OM treatment
plan system was performed taking Plato as the standard TPS used in clinicalpractice. Commissioning tests consisted in comparison of dwell times in simple catheter configurations, varying the length and the diameter of the cylinder
applicator used in clinical practice for endovaginal intracavitary gynaecological implants and the prescription dose. The source step was 2.5mm.Using
the option axis points, a set of dose points were created at 5mm external
to the applicator surface. The dose was optimized at these points.We used
Gafchromic EBT2 films to compare the isodoses obtained with the two treatment plannings.
Results: The better agreement between the dwell times of the two treatment
planning systems was obtained with DTGR 0.452 in OM and 0.5 used as default in Plato BPS, as previously indicated by C. Alves de Oliveira et al. Using
these parameters the total dwell time the agreement was under 1%.The differences obtained regarding dwell time in the central part of catheter reachedthe 50% in the case of cylinder applicator with diameter 35 mm and length 4
cm length; the prescribed dose was 500cGy.

680 poster
THE EFFICACY OF HYPERBARIC OXYGEN THERAPY IN THE
TREATMENT OF MEDICALLY REFRACTORY SOFT TISSUE NECROSIS AFTER PENILE BRACHYTHERAPY
A. Gomez-Iturriaga1 , J. Crook2 , W. Evans3 , S. Elantholi Parameswaran4 , J.
Jezioranski5
H OSPITAL DE C RUCES, Radiation Oncology, Baracaldo-Vizcaya, Spain
2
BC C ANCER AGENCY - C ENTRE FOR THE S OUTHERN I NTERIO, Radiation
Oncology, Kelowna B.C., Canada
3
TORONTO G ENERAL H OSPITAL, Hyperbaric Medicine, Toronto, Canada
4
P RINCESS M ARGARET H OSPITAL, Radiation Oncology, Toronto, Canada
5
P RINCESS M ARGARET H OSPITAL, Physics of Radiation, Toronto, Canada
1

Regarding QA measurements, mean and median differences between reference and measured dwell positions were both of 0.06±0.16mm, whereas
mean and median differences between reference and measured dwell times
were both of -0.03±0.03s. Setting tolerance values of 0.5mm and 0.1s, nomeasured value was outside these tolerances.
Conclusions: QuoVadis represents an accurate reliable and affordable tool
for the determination of some important non-dosimetric brachytherapy source
parameters recommended by the AAPM TG-56 protocol.
679 poster
SINGLE CENTRE EXPERIENCE USING 3D CT CONFORMALPLANNING FOR PATIENTS TREATED WITH INTRALUMINAL
BRACHYTHERAPY (ILBT) IN OESOPHAGEAL CANCER
G. Radhakrishna1 , P. Bownes1 , C. Richardson1 , K. Harris1 , G. Roe1 , E.
Brearley1 , D. Sebag-Montefiore1 , A. M. Crellin1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom
Purpose: Preserving swallowing function in patients with advanced oesophageal cancer is important for palliation. Intraluminal brachytherapy canbe used to maintain swallowing function. We compared the use of 3D
conformal planning and 2D planning for patients treated with intraluminal
brachytherapy in our centre.
Materials: 10 patients were treated in the St. James’ Institute of Oncology
from April to December 2010. All patients were treated with afterloading HDR
Ir192 (Nucletron) single line source treatment. Naso gastric loading tubes
were inserted under direct fluoroscopic guidance by a consultant radiologist.
6 patients have been treated with 30 Gy in 10 fractions 3 D Conformal External Beam Radiotherapy followed by a single 8 Gy ILBT boost, 2 patients hadbrachytherapy as salvage following local relapse after previous external beam
radiation (30 GY in 10 fractions) but were able to manage a soft diet and 2
patients had brachytherapy following local relapse after external beam radiation and failed stent insertions (due to stent migration).A standard prescription(SP) to a defined length was a single 8Gy dose prescribed to 1 cm from thesource axis on orthogonal radiographs for the first 5 patients treated.The last

Purpose: Soft tissue necrosis is reported in up to 26% of patients undergoing radiotherapy for penile cancer. Management options include local irrigation, wound debridement, antibiotics, local anti-inflammatories and analgesics. Refractory lesions may be treated with partial penectomy. Hyperbaric
Oxygen Therapy (HBO) has a well-defined role in the treatment of late radiation toxicities. We present our experience with HBO for medically refractory
soft tissue necrosis after penile brachytherapy.
Materials: From November 2001 to January 2009, 7 men of 43 treated withpenile brachytherapy for squamous carcinoma developed medically refractory
soft tissue necrosis and were treated with HBO. All had received a prescribed
dose of 60Gy through interstitial Pulse Dose Rate (PDR) brachytherapy using
Paris system guidelines. All had failed conservative medical therapies for soft
tissue necrosis.
Results: Median age was 55 years (range: 35-72). Co-morbidities potentiallyeffecting wound healing included hypertension in 2 patients but none haddiabetes mellitus, or peripheral vascular disease. Five were current smokers
and one a former smoker. Median time between completion of brachytherapy
and appearance of soft tissue necrosis was 13 months (range 9-24) and the
median interval before starting HBO was 7.5 months (3-13). The median
number of "dives" per HBO course was 40 (30-53). All 7 experienced an
excellent response with healing of the necrosis and resolution of symptoms,
although 3 required an additional course, two for consolidation of healing andone for a relapse 4 months later. No patient was submitted to penectomy.
Conclusions: Consistent with the evidence of its efficacy in other organ systems, HBO should be considered whenever possible as a management option in patients with medically refractory soft tissue ulceration of the penis
following radiation therapy.

Brachytherapy: Physics
681 poster
COMPARISON BETWEEN ONCENTRA MASTERPLAN AND PLATOBPS TREATMENT PLANNING SYSTEMS
M. Piergentili1 , C. D’Ambrosio1 , L. Mondini1 , S. Garelli2 , S. Agostinelli2 ,F. Foppiano1
1

ASL 5 "S PEZZINO ", S.C. Fisica Sanitaria, La Spezia, Italy
N ATIONAL I NSTITUTE FOR C ANCER R ESEARCH, S.C. Fisica Medica,
Genova, Italy2

Purpose: During the commissioning of the Brachytherapy module, version
3.2, of the Oncentra MasterPlan (OM) treatment plan system from Nucletron
we noticed different dwell time in respect of those obtained with Plato system, also from Nucletron. Our purpose is describe these differences and theresulting differences in the given doses

Conclusions: We assumed the differences in the dwell times at the extremities of the catheter are due to the new anisotropy modelling. Moreover wesupposed the differences in the dwell times in the central positions of thecatheters are due to the optimization process that works in a different andunexpected way in the two TPS.
682 poster
DOSE TO MEDIUM OR DOSE TO A WATER CAVITY EMBEDDED IN
MEDIUM?
S. Abbasinejad Enger1 , A. Ahnesjö2 , L. Beaulieu1
1

C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Département de Radio-Oncologie, Quebec, Canada
2
U PPSALA U NIVERSITY, Department of Oncology, Radiology and Clinical
Immunology, Uppsala, Sweden
Purpose: Traditionally in radiation therapy the absorbed dose has been computed and reported as dose to a Bragg-Gray water cavity enclosed in water,
Dw. In more modern dose calculation algorithms the transport and energy
deposition occur in the local medium and dose to local medium Dm,M or thedose to a water cavity embedded in the medium, Dw,M is reported. The question of which quantity should be adopted for comparison purposes is under
debate. The target for radiotherapy is to sterilize cells by imposing damage totheir DNA content. Cell nucleus with its DNA content is biologically the most
relevant dose target. In brachytherapy the photon energies are sufficiently
low that the ranges of secondary electrons may be close to the dimensionsof cell nuclei. Aim of this study was to investigate, by means of Monte Carlo(MC), the relations of Dm,M , Dw,M to Dc,M - the dose to a cell in medium,
Dn,M - the dose to a cell nucleus in the medium for different energies used inbrachytherapy and different cavity sizes.
Materials: Geant4.9.3.patch2 MC code is used to calculate Dm,M , Dw,M,
Dc,M and Dn,M. A parallel mono-energetic photon beam is let in across one
side of a cubic phantom (5x5x5 mm3 ). The phantom consists of different tissue material. The highest photon energy is 350 keV to represent the higher
energy end in brachytherapy i.e.192 Ir. The lowest energy is 20 keV to represent the lower energy end 103 Pd or 125 I. Spherical cavities representing cell(range 4-20 mm) and nuclei (2-10 mm) are placed inside the phantom at different depth depending on the energy of the photon beam to ensure CPE
conditions. Scatter is eliminated. Absorbed dose and electron fluence inside
the cell and the cell nucleus is scored. Absorbed dose is also calculated withthe large cavity theory (LCT) and smal cavity theory (SCT) and comparedto the MC calculated absorbed dose to investigate when to expect dominant
LCT or large LCT behavior, and for which photon energies we have intermediate conditions. Restricted and unrestricted stopping power values wereobtained by EGSnrc MC code.
Results: The lower end of brachytherapy energies is more sensitive to chemical composition of the cell and nucleus. The difference between cell lines

S 273

with different water content is significant. LCT for the lowest engeries is valid
down to 3 mm. For 3 mm nucleus MC calculated dose deviates from the dose
calculated with LCT.
Conclusions: There is a large variation between different Dn,M values depending on the cell line and the water content. Conversion factors used tocoververt Dm,M into Dw,M are not valid for all cell, nucleus size and bracytherapy energies.
683 poster
DOSIMETRIC ANALYSIS OF 30 INDIVIDUAL INTRACAVITARY
BRACHYTHERAPY TREATMENT PLANS GENERATED WITH THREE
BRACHY TREATMENT PLANNING SYSTEMS
A. B. Mohamed Yoosuf1 , G. Workman1 , M. O’toole1 , M. straney1
1
B ELFAST C ITY H OSPITAL, Radiotherapy Medical Physics Service, Belfast,
United Kingdom
Purpose: To compare geometric applicator reconstruction; prescription isodose volumes; organ at risk DVHs and inter-observer variability of High Dose
Rate intracavitary brachytherapy (ICBT) plans produced by three different
Treatment Planning modules.
Materials: 30 HDR intracavitary radiation therapy fractions were included inthis study. Orthogonal images using Nucletron integrated brachytherapy unit®(IBU) were acquired with applicators in situ. Subsequently, CT scanningwas carried out. 2D plans were produced on Nucletron Plato ®(N2DP) using
the IBU images. The CT data sets were imported into Nucletron Oncentra Masterplan ®(N3DO) and relevant OARs (rectum, bladder & bowel) were
contoured. 3D plans were produced with Nucletron 3D Oncentra Masterplan®, the image set with contoured structures were exported and also planned
using Nucletron 3D Plato ®(N3DP). Doses to 2cc volumes (D2cc) of OARs
(rectum, bladder, and bowel) were calculated for both 3D planning modules.
The implant volume enclosed by the prescription isodose was recorded for allplans. The applicator reconstruction variability between the treatment planning modules was evaluated by defining three parameters: the linear distance
between point A and plane of ovoid sources (l); separation of ovoids (s) andthe total treatment time (t). Each 3D plan was carried out by two independent
planners to assess inter-observer variability.
Results: A total of 150 plans were generated and evaluated in this study.
The mean implant volume enclosed by prescription isodose (100%) was measured to be 107.5cc (±18.2), 107.5cc (±18.4) & 110.4cc (±18.2) for N2DP,
N3DP & N3DO respectively. The geometric applicator reconstruction as defined by three parameters (l, s & t) agreed to within 1% for the three modules.
The mean doses recorded with N3DP to D2cc volume were 5.3Gy (±1.4),
3.7Gy (±1.1) & 4.5Gy (±1.3) for bladder, rectum & bowel respectively, while
N3DO, results were 5.5Gy (±1.5), 3.4Gy (±1.1) & 4.4Gy (±1.3) respectively. The mean difference in D2cc between N3DP & N3DO was found to
be 3.2%, 6.7% & 3.6% for bladder, rectum & bowel respectively. Our interoperator analysis between N3DP & N3DO showed that the mean difference
between two operators was 0.4% (±0.4) & 0.3% (±0.03) for geometric applicator reconstruction, 0.4% (±3.2) & 0.6% (±3.7) for volume enclosed by
100% isodose and 1.3% (±1.8) & 0.2% (±0.5) for dose-volume analysis of
OARs respectively.
Conclusions: The results demonstrate that for three treatment planning
modules the geometric applicator reconstruction is very reproducible whichgave confidence with reconstruction technique and assisted in the implementation of clinical 3D planning. The differences observed with D2cc in OARs is
most likely due to the proximity of the high dose region within the OAR to dwell
positions in the applicators and any slight variation in applicator localization
can result in relatively large differences in dose.
684 poster
DOSIMETRIC VALIDATION OF HDR TREATMENT PLANNING
SYSTEM USING DIODES AND SMALL VOLUME IONISATIONCHAMBERS
E. Hogg1 , S. Misson-Yates2 , S. Aldridge2
1

K ING ’ S C OLLEGE H OSPITAL, Medical Engineering and Physics, London,
United Kingdom
G UY ’ S & S T. T HOMAS ’ NHS F OUNDATION T RUST, Medical Physics,
London, United Kingdom

2

Purpose: The Flexiplan v.2.6 TPS calculates the radiation dose distribution
exposed to human tissue (water) in 3D for an 192 Ir HDR source (Flexisource).
At commissioning extensive validation of the Flexiplan TPS was conductedby manual calculations and film dosimetry with reference to the Monte Carlo(MC) data from the Granero paper and TG-43.The aim of this study is to experimentally verify the isodose data produced by the TPS, in multiple planes,
through comparison with both ion chamber and diode measurements in a
PTW MP3 water tank.
Materials: Tank QC was performed, based on advice given in IPEM 81, toestablish the accuracy of tank movements. A daily QC procedure was developed to ensure repeatability of both the Flexisource position within theapplicator and the source-chamber set-up.A titanium Rotterdam IUT applica-S 274B RACHYTHERAPY: P HYSICSB RACHYTHERAPY: P HYSICS

tor was fixed in a custom made jig, designed to hold the IUT approx. centred in the tank and at least 10cm away from any scattering surfaces.Dose
fall-off data was collected to allow inter-comparison of each chamber to the
MC data.The PTW chambers used were: PinPoint (PP) Chambers 31014 and
31016 (3D); Dosimetry Diodes P 60008 (shielded) and E 60012 (unshielded).
Both chamber types were chosen because they provide very high spatial resolution. Additionally the PPs are ideal for small fields and the diodes havehigh sensitivity.The effective points of measurement for the PP chambers
were established.Profiles were collected at multiple depths and distancesfrom the IUT to generate isodose plots in various planes. Data was collectedusing PTW MEPHYSTO v7.42 and analysed using PTW MEPHYSTO mc2
v.1.3. PTW VeriSoft v.4.0 was used to compare the isodoses to the TPS
using gamma analysis.

were implanted 1 cm center to center uniformly. Postimplant dosimetric verification was accomplished by obtaining a CT scan of the implant volume justafter the whole implant procedure.
Results: The mean PTV volume was 101 cc for the ten patients. 80 seeds
were implanted on the average, with the single seed activity of 0.5-0.8 mCi.
The mean activity implanted per cc PTV was 0.69 mCi. The mean D90 was
91.5 Gy, and V100 (the percentage of the PTV volume receiving 100% of theprescription dose) was 85.5%. The mean V150 and V200 were 68.9% and52.1%. The mean mPD (minimum peripheral dose) was 38.5 Gy.
Conclusions: Satisfactory dosimetric distribution can be achieved with CTguided 125 I seeds implant for recurrent rectal cancer. Uniform implants resultin inhomogeneous dose distribution, and low dose in the peripheral region oftargets due to the constraints of bony structures and organs at risk for somepatients.
686 poster
DOSIMETRY COMPARISON BETWEEN TG-43 AND MONTE CARLOCALCULATIONS USING THE FREIBURG FLAP FOR SKIN HDR
BRACHYTHERAPY
J. Vijande1 , F. Ballester1 , G. Domingo2 , Z. Ouhib3 , M. D. C. Pujades4 , J.
Pérez-Calatayud4
1
U NIVERSITY OF VALENCIA, Department of Atomic, Molecular and Nuclear
Physics , Burjassot, Spain
2
E RESA VALENCIA, Department of Radiation Oncology, Valencia, Spain
3
LYNN C ANCER I NSTITUTE OF B OCA R ATON C OMMUNITY H OSPI, Radiation
Oncology, Delray Beach , USA
4
H OSPITAL U NIVERSITARIO L A F E, Department of Radiation Oncology,
Valencia, Spain

Results: The accuracy of positional readouts of the tank was established tobe ±0.2mm. The daily positioning of the source was within ±0.5mm of expected. The centre of the source was established daily and for each detector
using profiles in both directions.Comparison of dose fall-off curves with the
MC and TPS data showed very good agreement for all detectors, with PP
31014 being the best: when normalised to 15mm the distance to agreementis ≤0.5mm (when distance to source ≤50mm) and magnitude of absolute difference is ≤1.3 percentage points. However, all the curves were found to fall
off more slowly than the MC and TPS data. The two diodes over-responded
at distance: at 60mm there was an absolute percentage difference of ~1.5%
compared with the MC data.Detailed analysis of the isodose data is being
performed.
Conclusions: The PTW MP3 water tank is suitable for dosimetric measurements of the HDR brachytherapy source and it is possible to collect data
as is required for this study.All chambers seem acceptable for collection of
HDR 192 Ir dosimetric data, with the PinPoint 31014 being the most suitable.Comparison of dose fall-off curves shows excellent agreement with themodelling of the source by the TPS; further comparison with full isodose data
will complete the study.
685 poster
DOSIMETRIC VERIFICATION OF CT-GUIDED 125I SEED IMPLANTAT IN RECURRENT RECTAL CANCER
R. Yang1 , J. Wang2

Purpose: Freiburg Flap (FF) is a flexible mesh surface mold with channels of
flexible implants tubes 1 cm apart. This device is used in HDR Brachytherapy
for skin treatment. It consists of a large sheet of connected plastic pellets of 1
cm in diameter that can be cut to sizes to accommodate the target area withadditional margins.The main purpose of the present work is to compare thedelivered dose to the skin surface and to the prescription depth (5 mm) using
TG-43 data (full scatter conditions in water) and Monte Carlo (MC) predicteddose (taken into account air surrounding the FF and its density and composition).It is of special interest to evaluate the possible existence of a scatter
defect on the skin.
Materials: A 5 mesh formed by silicon spheres of 1 cm diameter has been
considered. The phantom was a 3000 cm3 water cube surrounded by dry
air. The FF applicator is located on one of the sides in direct contact withwater. Primary and secondary dose, including contributions due to x-rays
and bremsstrahlung photons, have been stored using voxels z = 0.25 mm indepth into the water phantom and x = y = 1 mm parallel to the FF.The mHDRv2 source (Nucletron BV, Veenendaal, The Netherlands) has been simulated
as described in Daskalov et al. [Med. Phys. 25(1998)2200-2208]. As abenchmark and as dose kernels, two different source positions were chosen: at the center of the central sphere, and between two adjacent central
spheres. Experimental measurements have been done using radiochromic
films (RF).The superposition principle (SP) was applied to compare the dose
distribution as calculated by TPS using TG-43 data with that obtained applying SP but using kernels from individual source positions as described above.
A clinically optimized plan treatment was obtained locating the source at 35
different positions. The dwell times from this plan were used to derive therealistic dose rate distribution using the kernels previously obtained.
Results: MC and RF measured dose distributions agree within 3% in thesource vicinity, therefore validating the MC data. In these kernels the scatter
defect is up to 15% when the source at located in the center of the sphere andup to 25% when the source is between two spheres.The comparison of the
TPS plan with that calculated using kernels are illustrated in the figure thatshows the ratio between the TPS dose distribution and that obtained from
MC. Maximum deviations between these two distributions are of the order of
4 - 6%, well within tolerance limits, in both surface and 5 mm depth (1 cmfrom source positions) which is the typical prescription depth.
Conclusions: Deviations in the dose distributions for a standard treatmentusing TG-43 data with respect to that calculated taking into account the composition and shape of the FF and the surrounding air is lower than 5%. Therefore, this simulation support the validity of the TPS used in clinical practicewith the FF.

1

P EKING U NIVERSITY 3 RD H OSPITAL, Department of Radiation Oncology,
Beijing, China
2
U NIVERSITY OF B EIJING, Department of Radiation Oncology, Beijing,
China
Purpose: To verify the postimplant dose distribution achieved in recurrent
rectal cancer patients treated with CT-guided 125 I seed implant.
Materials: Ten recurrent rectal cancer patients treated with CT-guided 125 I
seed implant were selected for this study. Pre-implant plans were designed
one week before the implant, with the prescription dose of D90 (the dose
received by 90% of the target) of 100 Gy for planning target volume (PTV).
Implant needles were inserted according to the pre-implant plans, with theinterval of 1 cm and in parallel to each other under CT guidance. The seeds

687 poster
EFFECT OF USING DIFFERENT U/S PROBE STANDOFF MATERIALS IN IMAGE GEOMETRY FOR BRACHYTHERAPY
S. Diamantopoulos1 , S. Butt1 , N. Milickovic1 , Z. Katsilieri1 , V. Kefala1 , P.
Zogal2 , G. Sakas3 , D. Baltas1
1
K LINIKUM O FFENBACH G MB H, Department of Medical Physics andEngineering, Offenbach am Main, Germany
2
M EDCOM, Darmstadt, Germany
3
F RAUNHOFER IGD, Cognitive Computing and Medical Imaging, Darmstadt,
Germany

Purpose: This research investigates the distortion of needle imaging andanatomy geometry, caused by various standoff materials used for covering atransrectal bi-planar ultrasound probe in HDR and LDR prostate brachytherapy, during needle implantation. Furthermore, an evaluation of currently established water-bath based QA procedures is presented.
Materials: On a high resolution TPV 061 template (GfMMedizintechnik mbH,
Darmstadt, Germany), 9 stainless steel trocar needles (1.5 mm x 200 mm)(Nucletron B.V., Veenendaal Netherlands) were placed at symmetrical positions. The template was connected to a mechanical stepper (GfMMedizintechnik mbH, Darmstadt, Germany), a CLA 6.5/R10/2x128/BIP-1224 ultrasound probe (Vermon SA, Tours, France), LogicScan 128 INT-2Z beamformer(Telemed UAB, Vilnius, Lithuania ) and Biopsee® software (MedCom GmbH,
Darmstadt, Germany and Pi Medical Ltd., Athens, Greece) and placed vertically in a water tank filled with normal water at 37.7◦ C (rectum temperature). The materials that were put under test were: EA 4015 Silicone Standoff
kit (Civco, Kalona, USA), UA0059 Endocavity balloon (Civco, Kalona, Iowa,
USA), filled either with water or 40 ml of Endosgel® (Farco-Farma GmbH, Kln,
Germany) or 40 ml of Instillagel® (Farco-Farma GmbH, Kln, Germany) or with
40 ml of Ultraschall gel (Dahlhausen & Co. GmbH, Kln, Germany). For eachmaterial, image acquisitions were carried out at two frequencies (5 MHz and
7 MHz). The acquired images were compared to a pair of reference images
at both frequencies, having the ultrasound probe "uncovered" in the water.
Results: For Silicone Standoff kit, in normal water with sound speed of 1525
m/s, a 3 mm needle shift was observed, that expands dimensions of appeared
objects in radial direction, following the form of sound wave transmission. The
shift is independent of frequency and needle position. The use of Endocavity
balloon either filled with water, Endosgel® or Ultraschall gel, did not cause any
significant shift (0.3 mm) in needle imaging. On the other hand, Instillagel®
"shrinks" objects in an ultra-sound image. The average disposition of theneedles is 0.7 mm in the radial direction and towards the probe.
Conclusions: The use of Silicon Standoff kit and Instillagel® for image acquisition, leads to wrong reconstruction and placement of needles which will result to incorrect dose calculation during prostate brachytherapy. Moreover, as
speed of sound in normal water is closer to the speed of sound in soft tissue(1540 m/s), QA procedures should always be performed in normal insteadof distilled water (1480 m/s), for more accurate simulation of real conditionsof ultrasound imaging. The dosimetric impact of these findings is a work inprogress.
688 poster
EVALUATION OF THE I25-S06 SEED DESIGN DIMENSIONS USING
DESTRUCTIVE AND NON-DESTRUCTIVE METHODS
F. A. Siebert1 , D. Cutarella2 , M. Döring1 , I. Aubineau-Lanièce2
1
U NIVERSITY H OSPITAL OF S CHLESWIG -H OLSTEIN , C AMPUS K IEL, Clinicof Radiotherapy, Kiel, Germany
2
CEA, LIST, L ABORATOIRE N ATIONAL H ENRI B ECQUEREL, Gif-sur-Yvette,
FrancePurpose: Low dose rate (LDR) brachytherapy implants using Iodine-125
seeds are a worldwide well established technique to treat prostate cancer
in early stage. Doses are calculated individually for each patient by sophisticated brachytherapy treatment planning software (TPS). The computation of
the dose around the sources is based on the design of the source model.
Thus to follow the exact internal dimensions of the sources is of importancefor treatment algorithms like the TG-43 algorithm or more modern ones thatare based e.g. on the Linear Boltzmann Transport algorithm. Normally it is
not possible for the user to check the internal source dimensions. In this study
two different methods are presented to evaluate the seed design. Results arecompared for the IBt Bebig I25-S06 seed model.
Materials: In Method A, the non-radioactive sources were casted in a special resin and manually grinded until the half of the seed was cut. To checka parallel grinding process, markers were casted beneath the source to indicate the depth of stock removal. After the grinding process microscopic
digital photos were taken to evaluate the internal seed design. Using thistime-consuming method, three different I25-S06 sources were investigated.
Fifteen different seeds of I25-S06 type were analyzed with method B. In the
non-destructive technique, micro x-ray images were taken from the sources.
An appropriate dimensional calibrated piece of material was imaged simultaneously with each source to be used as a dimensional reference. The resulting digital images were enlarged, printed and manually investigated. To
reduce the subjective part of the measurement, each dimension assessment
was repeated at least four times using either a common ruler or a calliper
ruler. Considering the following summary of the results, the specified range
refers to the experimental standard deviation of the mean value.
Results: The measurements of the overall seed lengths resulted in 4.51 mm(range: 4.53 to 4.49) for method A and 4.49 mm (range: 4.47 to 4.51) for
method B. The specification (spec.) of the sources indicated a length of 4.56mm (Hedtj et al. Med Phys 27, 2000). Comparisons of the outer diameter
showed constantly 0.8 mm (spec. 0.8 mm). Furthermore, it was possible tomeasure the lengths and diameters of the ceramic cores. For method A, alength of 3.48 mm (range: 3.48 to 3.49), for method B of 3.52 mm (range:
3.48 to 3.56) were obtained (spec. 3.5 mm). The diameter of the ceramiccore was 0.59 mm (range: 0.58 to 0.60) and 0.64 mm (range: 0.63 to 0.65),

S 275

respectively (spec. 0.7 mm). Lengths of the gold x-ray marker were 3.51 mm(range 3.50 to 3.51) and 3.43 mm (range 3.40 to 3.46) respectively (spec.
3.5 mm). Diameters of the gold x-ray marker were 0.18 mm (range: 0.17 to0.20) and 0.17 mm (range: 0.16 to 0.18) (spec.0.17 mm). The thickness ofthe titanium wall was measured with 0.05 mm (range: 0.05 to 0.06) and 0.05
mm (range: 0.04 to 0.06) by the two techniques (spec. 0.05 mm). Diametersof the spherical welds on both ends of the source were observed to be 0.44
mm (range: 0.43 to 0.44) and 0.47 mm (range: 0.44 to 0.50) (spec. 0.44-0.48mm). In summary, a very good agreement between both methods and thespecification of the source was found. Only in the diameter of the ceramiccore differences of more than 0.1 mm between the grinding method and thespecification were measured.
Conclusions: Our investigation shows: a) it is possible to check the internal
design of LDR sources using destructive and non-destructive methods withhigh accuracy, and b) the manufacturing tolerances of the evaluated seedmodel I25-S06 are very small. Consequences from the tolerances of seeddimensions to the dosimetric outcome should be out of clinical impact.
689 poster
I-125 SEED CALIBRATION USING THE SEEDSELECTRONAFTERLOADER. PRACTICAL SOLUTION TO FULFIL AAPM RECOMENDATIONS
J. Pérez-Calatayud1 , J. Richart2 , J. Pérez3 , D. Guirado4 , F. Ballester5 , S.
Rodríguez2 , M. Santos2
1
H OSPITAL U NIVERSITARIO L A F E, Radiation Oncology , Valencia, Spain
2
C LINICA B ENIDORM, Radiotherapy Department, Benidorm, Spain
3
N UCLETRON E SPANA , S.A., Madrid, Spain
4
H OSPITAL U NIVERSITARIO S. C ECILIO, Radiotherapy Department,
Granada, Spain
5
U NIVERSIDAD DE VALENCIA, Department of Atomic, Molecular and Nuclear
Physics , Valencia, Spain
Purpose: SeedSelectron is an afterloader system used in prostate insterstitial permanent brachytherapy with I-125 seeds. The system is composedof an array of diodes to assay all implanted seeds. Because seeds are on
preesterilized cartridges, just 1-2 seeds can be assayed to check manufacturer SK and to calibrate the diode array. This is done during the intraoperative procedure once the interactive planning is completed assuming the
manufacturer SK value. To fulfil AAPM Recommendations two are the criticalpoints: high practical difficulties to assay the required seed quantity and the
low accuracy of the diode system.The purpose of this work is to present thepractical solution adopted to fulfil AAPM Recommendations.
Materials: An agreement has been done with Nucletron to obtain a separate container with 10 seeds from the same batch for all users under request.
These seeds are measured prior the implant.Seeds SK are evaluated using an ionization chamber (SourceCheck PTW Germany) calibrated at PTB(Germany) for the SelectSeed I-125 source model. To optimize the measuring procedure, in this work, an insert has been developed to be used leaned
to the wall chamber plate. It allows measuring SK of the overall 10 seeds
set.A corresponding factor to be operated by the camber calibration factor
was obtained for the developed insert from the calibration chamber factor using a NIST standard source. Chamber profile response along 10 cm length
was evaluated.Typical results are presented for 10 patients: comparison with
manufacturer SK from both the average of 10 non-sterile seeds and the isolated seed extracted during the intraoperative procedure
Results: Corresponding factor obtained has been 1.88 ±0.04. Chamber
profile response resulted within ±1.5%. For the 10 patients assayed, thevalues of the differences with manufacturer value for the 10 seeds had an
average, standard deviation and range of -1.81%, 0.02%, and -4.6% to 3%
respectively; and isolated seeds: -2.9%, 0.03%, -7.8% to 2% respectively.
Conclusions: This new solution allows evaluating seeds SK prior the intraoperative procedure, avoiding the diode limitations and the deviations because
dispersion/uncertainty involved in just one seed assay. The developed insert
allows to perform efficiently the mean SK evaluation. This procedure has
been adopted by Nucletron to be extended to all SeedSelectron users.
690 poster
IMPLEMENTATION OF AN IMAGE GUIDED BRACHYTHERAPY(IGBT) SERVICE
G. Liney1 , M. Bush1 , J. Marsden1 , A. Beavis1
1

C ASTLE H ILL H OSPITAL, Radiation Physics, Cottingham, United Kingdom

Purpose: Following recommendations by the gynaecological GEC-ESTRO
working group [1] we have adopted Image Guided Brachytherapy (IGBT) for
treatments of cervical carcinoma using a HDR Flexitron unit. This involves
treatment over three fractions; the first utilising CT fused with MRI with theremaining two fractions using CT-only. This work describes how we have addressed the important 3D volumetric considerations at our Centre, ensuring
the safe and effective transition to this new technique.
Materials: An initial simple phantom was made with our Stockholm applicator set in gelatine to simulate in-vivo tissue. This was imaged for a range of

S 276B RACHYTHERAPY: P HYSICSB RACHYTHERAPY: P HYSICS

pulse sequences and acquisitions at 1.5 and 3.0 Tesla to characterise the appearance of the applicator. The phantom was further modified by adding anarray of Perspex rods fixed around the tube and ring to assess susceptibilityinduced distortion. This phantom was imaged with MRI and also CT to provide a gold-standard dataset. Images were transferred to the RTP system(Flexiplan) to test both the geometric accuracy of the MRI and the fusion
process. In order to verify the 3D planning accuracy of our RTP system,
in-house developed software (’BrachyChecker’) was written (MATLAB). Thiswas designed to be a GUI-application that enables the applicator and dwell
positions to be visually displayed in three dimensions and dose calculated
at any given point together with an independent planning activity check. The
RTP files containing source position data were exported from the RTP system
and used in conjunction with previously published tabulated source strength
data [2] to calculate dose. Various interpolations of the source data were
evaluated in terms of accuracy for both simple plans and real applicator configurations.
Results: MR imaging of the phantom was useful in characterising the appearance of the intrauterine (IU) tube and ring for various sequences anddemonstration of an artefact along the tandem that is related to its angulation
with B0 (Figure 1(a)). The phantom also enabled us to test the acquisitionof oblique imaging which was subsequently adopted to reduce partial volume
effects in the CTV. Results show that the fast spin-echo sequence demonstrated only negligible distortion in the immediate vicinity of the IU tube andring (Figure 1 (b)). The BrachyChecker software demonstrated an agreement
to within 0.19 % of Flexiplan values using a spline interpolation and this has
since been implemented as our secondary dose verification method (Figure1(c)). Figure 1: (a) (left) 3D renderings of the applicator for various protocols and an example image through the IU tube. (b) (middle) CT and MR
images of the distortion phantom shown at the level of the IU tube. (c) (right)
Screenshot of the independent second check software.

Conclusions: IGBT represents a step-change in complexity that requires
a comprehensive and robust QA procedure with particular attention placedon the volumetric imaging and planning aspects. The work described here
has enabled us to successfully deliver the first 18 months of this service withconfidence and will be useful for other Centres as they seek to implement thistechnique.
References:
1. Haie-Meder C et al. Recommendations from gynaecological (GYN)
GEC-ESTRO working group (I): concepts and terms in 3D image
based 3D treatment planning in cervix brachytherapy with emphasis on
MRI assessment if GTV and CTV. Radiotherapy Oncol 2005; 74:23545.
2. D. Granero et al. A dosimetric study on the Ir-192 high dose rate flexisource. Medical Physics 2006; 33:4578-82.

691 poster
INTERSEED ATTENUATION EFFECTS IN I-125 SEED IMPLANT
PROSTATE BRACHYTHERAPY
J. Mason1 , P. Bownes1 , B. Al-Qaisieh1 , A. Henry2 , D. I. Thwaites1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Department of Medical Physics and Engineering, Leeds,
United Kingdom
2
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Clinical Oncology, Leeds, United Kingdom
Purpose: TG43 based dose calculations for prostate permanent I-125 seed
implants ignore the effects of inter-seed attenuation (ISA). This study investigates the magnitude of ISA effects in simple seed arrangements and clinicalimplants using Monte Carlo (MC) simulation techniques. MC results are verified with experimental dose measurements. ISA effects for Oncura™model
6711 and Thinseed™(9011) are compared.
Materials: MC simulations were performed with MCNPX v2.5.0. Seed models 6711 and 9011 were simulated singly to verify the accuracy of the modelby comparison to previously published data. Then simple two seed arrangements and full clinical implant arrangements were simulated to assess ISA
effects and consequences for typical patient DVH parameters. Experimental dose measurements using a MOSFET in a PMMA phantom were used tovalidation MC simulation results.

Results: Close agreement with published data was achieved for both seedmodels. Two seed arrangements demonstrate significant attenuation along
the source transverse axis with the 9011 being slightly less attenuating. Clinical simulations show that ISA has significant effects on clinical dose-volume
histogram (DVH) parameters. Experimental dose measurements agree with
MC simulation results.
Conclusions: The study demonstrates the need to take account of ISA effects in permanent I-125 seed implant treatments. Ongoing work will investigate post implant dosimetry using MC simulation to determine when ISA
effects are clinically significant.
692 poster
ISODOSE SELECTION FOR DOSE PRESCRIPTION IN OPTIMIZEDHDR BREAST IMPLANTS
G. Fröhlich1 , T. Major1 , C. Polgár1
1
N ATIONAL I NSTITUTE OF O NCOLOGY, Department of Radiotherapy,
Budapest, Hungary
Purpose: To evaluate the optimal dose prescription in treatment plans ofimage-based high-dose-rate (HDR) partial breast brachytherapy (BT) implants.
Materials: Treatment plans of 34 patients with early stage breast cancer were
evaluated based on dose-volume histograms. 30.1Gy was prescribed to the
PTV, geometrical and graphical optimisations were applied. The dose reference points were placed in the central plane of the catheters (basal dosepoints), and dose was normalized to its mean (Mean Central Dose, MCD).
The dose prescription was determined by the F-factor (the ratio of the reference dose and the MCD). The following constraints were used: PTV coverage(CI) ≥ 0.9, dose homogeneity (DNR) ≤ 0.35 and dose to skin ≤ 70%. Ffactor was modified between 0.5 to 1, and the corresponding DNRs and CIs
were calculated.
Results: With increasing F-factor the DNR is decreasing in HDR breast BT
plans, and it has a minimum (DNR=0.19) at F=0.85, while the dose coverageis decreasing monotonously (CI: 1-0.39), which is not clinically acceptable
under 0.9. The optimal dose prescription in terms of dose coverage andhomogeneity is around the 0.74 value of the F-factor, where DNR=0.25 and
CI=0.96 in average. In the treatment plans of our 34 patients the average
F-factor was 0.75 (0.70-0.85), the DNR was 0.32 (0.25-0.41) and the CI was
0.92 (0.9-0.96).
Conclusions: The ideal dose distribution regarding dose homogeneity andcoverage is can be obtained with around 0.75 value of the F-factor for doseprescription in HDR breast BT implants, which is lower isodose than 85% of
the MCD used in the Paris Dosimetry System.

S 277

694 poster
MONTE CARLO CALCULATION OF DOSE DISTRIBUTIONS FOR
ASYMMETRIC CIA-TYPE 106-RU/106-RH OPHTHALMIC PLAQUE
M. Hermida Lopez1 , A. Seoane1
1

H OSPITAL U NIVERSITARIO VALL D ’H EBRON,
Barcelona, Spain

Physics Department,

Purpose: 106 Ru/106 Rh ophthalmic plaques have been used for decades totreat choroidal melanoma with good clinical outcome. Dosimetry of suchplaques is complicated by the steep dose gradients and the spherical shapeof the plaques. Most publications available were focused on symmetricplaques. We calculated absorbed dose to water distributions for asymmetricCIA-type plaque, for which no published data is available, with PENELOPE
2008.1 Monte Carlo (MC) code.
Materials: First, a planar 106 Ru/106 Rh non-clinical plaque was simulated tovalidate PENELOPE physics model for low-energy β radiation with a simple geometry. Then, a model of asymmetric CIA-type 106 Ru/106 Rh plaque
was created with PENELOPE, based on ICRU Report 72 data and information provided by manufacturer (IBt Bebig, Berlin, Germany). CIA plaque has
an external diameter of 15.3 mm and a radius of curvature of 12 mm. Radioisotope is encapsulated at a 0.1 mm depth within pure silver sheets witha total thickness of 1 mm. We assumed a uniform radioisotope distribution
and only 106 Rh β -spectrum (Emax = 3.54 MeV) was considered. Plaque
was assumed to be immersed in water. PENELOPE simulation parameters
were selected for a compromise between accuracy and calculation speed:
EABS(e- ) = EABS(e+ ) = 70 keV, EABS(photons) = 10 keV, C1 = C2 = 0.1,
WCC = 30 keV, WCR = 4 keV. No variance-reduction techniques were applied. 108 histories were simulated for each plaque. For planar plaque, absorbed depth dose to water along the central axis was calculated and compared with published data. For CIA-type plaque, absorbed dose to water
profiles along the central axis and transversal dose profiles at depths of 2, 4
and 6 mm were calculated. In both cases, calculation bin size was 0.5 mm.
Results: The statistical uncertainty attained in our calculations was within
2% (3σ level). For planar applicator, our depth dose curves agreed within
2% in the range 0.5-8 mm with published measurements and EGS4 MC code
calculations (ICRU Report 72). For CIA plaque, our calculations are shownon the figure. For clarity, statistical uncertainties (±3σ ) are not shown on all
the graphs. Where not plotted, error bars are the size of data points. Dosecurves are normalized at a point 2 mm depth along the central axis.

693 poster
MANUAL AND AUTOMATIC TREATMENT PLANNIG IMAGE-GUIDEDCERVICAL CANCER BRACHYTHERAPY TRETMENT PLANS
M. Paluga1 , M. Kolarcik1 , P. Trnkova2 , R. Pötter2 , C. Kirisits2
1
N ATIONAL O NCOLOGY I NSTITUTE, Department of Radiation Oncology,
Bratislava, Slovakia
2
M EDICAL U NIVERSITY V IENNA , AKH, Department of Radiotherapy,
Vienna, Austria

Purpose: To report manual and automatic multiple replanning of 3D MRI
brachytherapy treatment plans for cervix carcinoma and to evaluate set of"importance factors" (I.F.) in HIPO algorithm used for the automatic optimizations.
Materials: The Oncentra Gyn (Nucletron) is a treatment planning system(TPS) containing reconstructed Vienna applicator in its own library. Ten clinically used treatment plans were replanned several times to study differences
between individual manual and automatic optimizations. The DVH parameters for HR CTV and OARs (bladder, rectum, sigmoid) based on GYN GEC
recommendations were analysed for more than 50 plans. Moreover, doseto point A (A1, A2), the volume of reference isodose (Vpd, V2pd) and conformity index (COIN, considering both, HR CTV and OARs) were evaluated.
For automatic optimization the standard pattern of dwell positions was always
used.
Results: Volumes of HR CTV varied from 13 to 44cm3 . The automatic optimized plans had the highest value of COIN for all ten cases. Apart from one
case the lowest Vpd values were related to automatic optimization. The Vpd
values for the both manual and automatic plans varied from 35 to 127cm3 .
There were used 5 I.F. as an arguments in HIPO algorithm. Variation intervalof I.F. values was for HR CTV (10-100), sigmoid (10-30), sectum (0.1-100),
sladder (0.01-20) and normal tissue (0.1-10). The mean I.F. values are for HR
CTV 57.9, sigmoid 15.2, rectum 15.5, bladder 10.2 and normal tissue 1.1.
Conclusions: It is convenient to use automatic optimization of dwell times togenerate several plans and select the most optimal treatment plan according
to the set of parameters. However, careful evaluation of the spatial dose
distribution is essential to control the results of the optimizer.

Conclusions: PENELOPE-2008.1 MC code, with the chosen simulation parameters, could accurately calculate dose distributions for 106 Ru/106 Rh planar
plaque, compared with published data. We calculated depth and transversal dose profiles for asymmetric CIA-type 106 Ru/106 Rh ophthalmic plaque, forS 278B RACHYTHERAPY: P ROSTATE C ANCER

B RACHYTHERAPY: P HYSICS

which no published data are available. Attained statistical uncertainty waswithin 2% (3σ ).
695 poster
SOURCE PATH MEASUREMENTS FOR RING APPLICATORS
Y. Niatsetski1 , S. Fekkes2 , H. Vreeken1
1
N UCLETRON BV, RD, Veenendaal, Netherlands
2
N UCLETRON BV, Service, Veenendaal, Netherlands
Purpose: To determine the actual source positions in the ring applicators inorder to use the measured source path in brachytherapy treatment planningsystemMaterials: Full set of Nucletron metal and plastic ring applicators and afterloaders, including microSelectron HDR and PDR classic and v2/v3, as well
as Flexitron treatment units.
Results: Two sets of measurements were completed, using modified plastic rings with transparent ring cups to visually access the source channel
and make digital camera images of the dummy source in each of the visible
dwell positions; and metal and non-modified plastic rings and X-ray imaging (simulator) in two orthogonal projections, providing 3D coordinates of all
possible source positions within the ring part of the applicators. Each of thedata sets is based on a number of dummy source runs, providing the possibility to evaluate the uncertainties of the measured source positions. These
uncertainties are smaller in the connector part of the ring tube than in thetip part. The largest observed uncertainty for the whole range of measurements was about ±1.5 mm. The largest source of uncertainties (< 2.0 mm)
is the difference between the afterloader and source combinations (including the source cable), used for the same ring tube. The uncertainties dueto the differences in the ring tube for the same afterloader are significantly
smaller (< 0.7 mm). The impact of the separate source runs for the same afterloader and the same ring to the total uncertainty is even lower (< 0.3 mm)
and is in the order of the digitization procedure accuracy.The measurements
resulted in 72 source path data sets, covering the four types of sources (Flexisource 192-Ir, 192-Ir-mHDR-v1, 192-Ir-mPDR-v1, and 192-Ir-mxDR-v2 usedin microSelectronHDR-v2, microSelectronPDR-v2 and microSelectron-v3 afterloaders) and 18 types of ring tubes (9 metal and 9 plastic, both of threedifferent diameters and three different angles).The measurements showedthat the distance between the neighboring dwell positions changes in different parts of the ring tube. In the first (connector) part of the ring tube thedistance is equal or very close to the step size of the source set at the afterloader. In the area around the middle part of the source path the distance
between the dwell positions is significantly smaller than the expected stepsize, because the increased friction between the source, source cable andthe ring tube forces the source cable to roll out along the outer lumen wall
while the source only rotates. In the tip end of the ring tube the distance
between the dwell positions is slightly smaller than the expected step size,
varying for different types of ring tube and afterloader.All measured source
paths cover the complete range of dwell positions in the ring part of the tubes
without gaps between the dwell positions. In the majority of clinical cases
the dwell positions are defined only in few ring segments. The selected dwell
positions during the discrete source run were compared to the same dwell
positions during the full source run. The correspondence was found to be acceptable. The displacement of the source positions is within the uncertainties
found for the same positions on the source path of the full run.
Conclusions: For the ring applicators, having a large curvature and substantial inner lumen diameter, actual source positions do not coincide withthe central line in the catheter’s lumen. The distance between the consecutive dwell positions in some ring segments is smaller than the step size ofthe source, defined at the afterloader. The measured source path shall be
used instead of the theoretical central line based path as more accurate fortreatment planning.
696 poster
USING IPSA ALGORITHM IN DOSE PLANNING FOR CERVIX HDRBRACHYTHERAPY WITH THE UTRECHT APPLICATORS. FIRSTPHASE RESULTS
D. Krishnamurthy1 , A. J. Cunha1 , I. C. Hsu1 , J. Pouliot1 , J. PérezCalatayud2 , A. Tormo2 , V. Carmona Meseguer2 , F. Lliso2
UCSF C OMPREHENSIVE C ANCER C ENTER, Department of Radiation
Oncology, San Francisco CA, USA
2
H OSPITAL U NIVERSITARIO L A F E, Radiotherapy Department, Valencia,
Spain

1

Purpose: Several studies using Inverse Planning Simulated Annealing(IPSA) for cervical brachytherapy optimization have been published. However, different institutions may use different applicators and have different implant techniques so they may lead to different dosimetric results. In this year
our centre has incorporated the Utrecht applicator (Nucletron), it consists of atandem plus ovoids with a set of plastic needles inserted in each ovoid. The
purpose of this study is to compare our forward planning approach (FWD)with the IPSA approach.

Materials: 11 intact cervical cancer patients treated using HDR brachytherapy at the University Hospital La Fe in Valencia (HULFV) were used in thisstudy. All implants were done using the Utrecht interstitial applicator, withtandem and ovoids plus 2 to 3 interstitial catheters. The original plans were
performed using HULFV’s FWD method. It consists of a prescription to thedose points around the HR-CTV and graphical optimization slice by slice.
An iterative evaluation is done to reach the required EQD2 values for D90
HR-CTV, D90 IR-CTV, D2cc OAR (sigmoid, rectum and bladder) according
to GEC-ESTRO Recommendations. All the patients’ data (MR based structure set, plan and dose) were then exported to Oncentra MasterPlan system
at University of California San Francisco (UCSF). The same contours including: HR-CTV, rectum, bladder and sigmoid were used for IPSA planning, withexception of an additional applicator contour (outline of the ovoids). The optimization was done at UCSF by completely using IPSA without any manualadjustment of the source dwell times.
Results: Dosimetric data obtained using IPSA were compared to the forward
planning approach. The HR-CTV average V100 values for IPSA and FWD
were 93.5 ± 4.6 % and 90.0 ± 15.6 % respectively. Similarly the average
V75 values for rectum, bladder and sigmoid colon were 0.3 ± 0.4 cc and 0.8± 1.3 cc; 0.7 ± 0.5 cc and 2.1 ± 3.1 cc; and 0 ± 0.1 cc and 0.1 ± 0.1 cc
respectively. The average implant V100 value was 11.1 ± 21.6 cc and 25.4
± 24.7 cc. In the FWD approach some dwell positions outside the HR-CTV
were routinely activated. The average FWD took approximately 30 minutes
per patient. Optimization using IPSA which involved running and adjust IPSA
parameters took on average 15 minutes per patient.In a second phase, D90
for HR-CTV and IR-CTV, D2cc for OARs and weight of the interstitial component versus tandem plus ovoids will be evaluated.
Conclusions: Our first phase study showed that IPSA gives promising results on HR-CTV coverage and OAR sparing for all the cases. This projectwill help in producing a class solution to be applied for this applicator modality
in order to make IPSA a very consistent and efficient tool in clinical practice.

Brachytherapy: Prostate Cancer
697 poster
A 7 YEAR EXPERIENCE OF PROSTATE HDR BRACHYTHERAPY AS
MONOTHERAPY: ANALYSIS OF OUTCOME AND TOXICITY
S. Sacco1 , R. D’Amico1 , C. Frigerio2 , G. Sangalli2 , F. Declich2 , A.
Colombo1
1
O SPEDALE "M ANZONI " DI L ECCO, Radiation Oncology Department, Lecco,
Italy
2
O SPEDALE "M ANZONI " DI L ECCO, Medical Physics Unit, Lecco, Italy
Purpose: to estimate the dosimetric aspects, the toxicity and the clinical outcome of the 3D Conformal HDR brachytherapy (BRT) as monotherapy treatment of localized prostate cancer.
Materials: 166 patients with prostate cancer (T1c-T2cN0M0) were treatedin our institute from November 2003 to December 2010 using 3D conformal
HDR brachytherapy as monotherapy with a temporary implant. The mean
age was 66 years with a range of 47-81 years. 106 patients were low risk, 51
intermediate risk and 9 high risk. 156 patients were treated with 4 fractionsof 9.5 Gy (2 fractions/day in 2 days) whereas 10 patients received 2 fractionsof 13 Gy (in one day). The treatment plan was elaborated using CT based
software to perform 3D conformal dose planning aided by an inverse planningalgorithm using these dosimetric constraints for OAR: dose receveid by 2ccof rectum (D2cc) < 75% of prescription dose (PD); D2cc of bladder < 80%PD.
For the urethra: the dose received by 1% of volume (D1%) < 115%PD and
D10% < 110%PD. The prescription for the target was D90% > 95%PD.
Results: Regarding the dosimetric aspects, we obtained satisfactory dose
distributions in terms of PTV coverage (D90%>100%PD), with a strict respectof OAR constraints. Overall survival and cause specific survival rates were96% and 100% respectively, with a minimal follow up of 12 months. Biochemical disease free rate was 96% with a minimal follow up of 12 months:
the specific rates were 99%, 94% and 90% for low, intermediate and high risk
respectively. Genitourinary (GU) toxicity was modest in spite of high urethral
dose: 46 patients of 166 (28%) showed an acute GU toxicity > G2 whereas
30 patients showed late G2 toxicity (18%) and 3 patients late G3 (2%). A
5% of the patients showed a chronic GU toxicity > G2. Gastrointestinal (GI)
toxicity rate was very low: 3 patients of 166 (2%) showed an acute GI toxicity> G2 whereas 10 patients showed late G2 toxicity (6%) and 1 patients late
G3 (1%).
Conclusions: From our experience, HDR BRT is a valid treatment modality
for patient with localized prostate cancer, in terms of both biochemical and local control as well as toxicity. Future studies can be addresses to evaluate thegain in quality of life that can be achieved with this technique and to evaluate
other hypofractionated schedules.
698 poster
ACUTE TOXICITY IN PATIENTS TREATED WITH SELECTIVE HDRIMAGE GUIDED BOOST TO DOMINANT INTRA-PROSTATIC LESION
R. Apardian Manougian1 , E. Vigneault1 , E. Chevrette2 , S. Aubin1 , L.
Beaulieu1
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Département de Radio-Oncologie, Quebec, Canada
2
CHUQ-CHUL, Department of Radiology, Quebec, Canada
Purpose: To report acute (6 months) genito-urinary (GU), gastro-intestinal(GI) and sexual toxicity (SxT) in patients treated with inverse-planned selective HDR brachytherapy boost to the dominant intra-prostatic lesion (DIL) defined with magnetic resonance spectroscopy (MRS).
Materials: We analyzed data prospectively collected from 8 patients treatedin 2010 for localized intermediate risk prostate adenocarcinoma. Before theCT Planning, all patients had an MRI/MRS to define the DIL. After while, theyreceived external beam pelvic radiation (40-44 Gy in 20-22 fractions) followed
by HDR (Ir-192) brachytherapy boost. The boost dose was 15Gy in one fraction to the whole gland with simultaneous 3Gy selective boost to the DIL.
All patients were planned with inverse-planning simulated annealing (IPSA).
Thereafter, IPSS score, GU/GI toxicities and sexual function questionnaires
were completed prospectively at each 3 months follow-up visit.
Results: The median age was 63 years. 50% of the patients had clinicalstage T1c and 50% T2a-b. All patients were Gleason score (GS) 7 with 62.5%
GS (3+4) and 37.5% GS (4+3). The initial PSA was ≤ 10ng/ml in 87.5% of
our patients while 12.5% was between 10-20ng/ml. No patients received hormonotherapy. The average IPSS score at baseline and 6 months were 5.5/35
and 5.25/35 respectively. At 6 months 50% of patients presented no GI symptoms and 50% occasional GI symptoms. No patients presented severe GI
toxicity at 6 months. The baseline sexual function (SHIM-like test scoring)
revealed no erectile dysfunction in 71.4%, mild erectile dysfunction in 14.3
% and severe in 14.3% of the patients. At 6 months there were no erectile
dysfunction in similar in 75%, mild erectile dysfunction in 12.5 % and severein 12.5% of the patients. Noteworthy the 2 patients who presented importantsexual dysfunction before and after EBRT refused the medication. The median D90 was 15.5 (range 16-15.1 Gy) and the V100 was 93.32 (95.96-91.02)% with a urethral V125 of 0.15 (0.7-0.01) % and a rectal V75 of 1.13(2.1-0.35)

S 279

cc. The V40 in the rectum was 18.7 %( 31.7-11.9). The Rectum D2cc was
10.2(11.3-8.95) Gy and D5cc = 8.4(9.3-7) Gy. The average of prostate volume was 61.02 cc. Even if the number of patients is small, the acute toxicity
observed compared favorably with patient who received a 15 Gy HDR boost(without selective DIL boost) in our institution (N=138).
Conclusions: Selective DIL image guided (MRS) HDR brachytherapy boost
in intermediate risk cancer, is feasible with acceptable acute GU and GI toxicity. It is also associated with good sexual function at 6 months. Longer
follow-up is necessary to evaluate late toxicity and tumor control.
699 poster
BENEFIT OF DUAL IMPLANT VS. SINGLE IMPLANT STRATEGY IN
TWO-FRACTION HDR BRACHYTHERAPY FOR PROSTATE CANCER
A. Rink1 , D. Jaffray1 , C. Menard1
1
P RINCESS M ARGARET H OSPITAL, Radiation Medicine Program, Toronto,
CanadaPurpose: HDR brachytherapy for prostate cancer has been gaining momentum, but the fractionation scheme, imaging method, and implant strategy varysignificantly between centres. Two main strategies exist: single implant performed once, and catheters left in for all fractions; new implant performed
prior to each fraction. While there are pragmatic benefits to both strategies,
the objective of this modeling experiment is to investigate dosimetric benefitsof dual- versus single-implant strategy in HDR prostate brachytherapy. The
hypothesis was that Dmin would increase, while hyperdose volumes (>150%)
would decrease.
Materials: A geometric model of prostate, urethra and rectum was created,
and imported into Oncentra MasterPlan. The prostate consisted of a halfcylinder 6 cm in diameter and 3 cm in length, with a 5 mm diameter urethra
through it. The 4 cm in diameter rectum was positioned 2.5 mm posterior
to the prostate. Fifteen HDR brachytherapy plans were created by simulating semi-random positions of fourteen catheters within the prostate, andimporting those positions into MasterPlan. Dwell positions and times were
optimized using IPSA and standard criteria for plan dose objectives. Ideally,
V100%>98%, but V100%>95% were accepted as long as V95%>98% andV150%<50% were satisfied for the prostate gland. D0.5cc<75% for rectum,and D0.5cc<125% for urethra were used. The plans were then combined withitself (single-implant), and with each of the other plans (dual-implant) in theanalysis module. No organ deformation or volume change between first andsecond fraction was assumed. Dosimetric parameters for prostate, rectumand urethra were recorded for each combination.
Results: The average V100% for single-implant was 97.8 ± 1.0, comparedto 99.2 ± 0.5 for dual-implant. Selecting only the sub-optimal implants(95%<V100%<98%), the average V100% was 96.6 ± 0.8 for single-implant.
When combined with another implant, this increased to above 98, even if another suboptimal implant was used. D90%, V95%, V150% and Dmin werealso higher for dual-implant plans compared to single-implant, although not
all increases were statistically significant (using α=0.01). No statistically significant reduction in hyperdose volumes (V200% and V300%) were observed.
No statistically significant changes in dosimetry for urethra and rectum wereobserved.

Conclusions: Dual-implant strategy has shown overall better coverage of theprostate with improvement in both D90 and V100%. This resulted in a slightincrease in V150%, but no significant changes in V200%, V300% or to thedose of rectum and urethra. Our next objective is to investigate whether afurther improvement in dosimetric parameters can be achieved by utilizing information from first fraction to position catheters for the second fraction, rather
than relying on a semi-random approach, and to establish clinical impact byusing radiobiological weighting.

S 280B RACHYTHERAPY: P ROSTATE C ANCER

B RACHYTHERAPY: P ROSTATE C ANCER

700 poster
BIOLOGICAL EFFECTIVE DOSE (BED) CALCULATION FOR
PERMANENT 125I SEEDS IMPLANTATION FOR MONOTHERAPYPROSTATE TREATMENT
M. Dennehy1 , A. Zuchora1
1

U NIVERSITY H OSPITAL G ALWAY, Department of Medical Physics andBioengineering , Galway, Ireland Republic ofPurpose: Brachytherapy seeds implantation is used for both monotherapy
and boost treatments of prostate cancer. Permanent 125I seeds are implanted in the prostate under transrectal ultrasound (TRUS) guidance throughthe perineum. D90 (dose delivered to 90% of contoured PTV), V100 (PTV volume to receive 100% dose), V150 (PTV volume to receive 150% prescriptiondose), Dose Volume Histogram (DVH) are the commonly used parameters fordose reporting in prostate brachytherapy. However, these parameters are notconsidered adequate to fully characterise the biological response to the implant. BED provides a direct measure of the amount of cell kill that result froma given irradiation. Many studies have found BED to be a highly significant
predictor of biochemical control. In this study two BED calculation methods
are compared.
Materials: The D90 value is calculated by Variseed software both during theseed implant procedure using TRUS and 30 days post implant using CT. Bothof these D90 values were used for analysis. BED calculation was carried out
using the Dale method as defined in AAPM TG137 and also using the Stockmethod. The associated formulae and input parameters for each BED method
were entered into a Matlab M-file for calculation.
Results: The BED values calculated using data gathered from 83 monotherapy prostate seed patients at UHG have been compared with results reported
in literature. The average Dale BED value (127Gy SD 13) is slightly higher(~10Gy) than comparable studies, however 76% of patients had a BED valueof greater than 116Gy which has been previously cited as the lower limit indicating a "good quality implant". The average Stock BED value calculated(164Gy SD 14) is also within the range reported in literature. Comparing bothmethods the Dale BED values were 25% to 35% lower than Stock values
which is also reported in literature. The histograms of BED values using bothmethods for the population studied are shown in figure 1.

Conclusions: The BED information provides a useful input into any discussions around the dose-response relationship in prostate seed brachytherapy.
Adequate long-term follow-up is the most important consideration in confirming the treatment outcomes. The next step is to correlate the BED values tothe clinical outcomes and from this analysis create a BED limit above which
an implant can be classified as good quality. Thus by correlating BED ranges
with clinical data a separate BED limit would be set for the Dale or Stockmethods. Generally the BED value is useful for comparing outcomes withresults from different treatment modalities i.e. external beam alone. Also forcomparison with other studies, it is important to clarify the definition of the
PTV contour used as this can vary in different institutions.
701 poster
C-ARM CONE-BEAM CT AND TRUS GUIDED HDR-BOOST FOR
PROSTATE TREATMENT
R. Westendorp1 , T. Nuver1 , A. van der Molen2 , J. Kosse2 , J. Immerzeel2 ,ternal beam procedure, four fiducial gold markers were implanted. The onestop brachytherapy procedure was performed in an operating theatre: Theradiation-oncologist first determined the needle configuration with TRUS. The
prostate was fastened with two fixation needles and the first TRUS-scan was
obtained. After that, steel needles were inserted in the prostate if needed.
One additional gold-marker was placed posterior at the apex to serve as alandmark for co-registration later on. After finishing the implant the legs ofthe patient were lowered, the pressure of the TRUS-probe to the prostate
was minimized and a second TRUS scan was made. A 3D C-arm fluoroscopic unit with isocentric design was then used to generate CBCT images
without the probe in the rectum and with the legs lowered. Slices were reconstructed at 1 mm intervals, enabling accurate localisation of needle-tips
and gold-markers. A PA X-ray image was made as a reference to determine
possible shifts of the implant with regard to the prostate markers. Prostate,
rectum and urethra were contoured. The urethra was contoured including asafety margin to prevent overdosage. The CBCT scan was registered to thesecond TRUS with a marker based registration on several peripheral needletips and the apical gold marker. A treatment plan with a prescribed dose of 10
Gy to the prostate was made. Just prior to treatment another PA X-ray image
was made and compared to the first. Shifts of the needles were determinedwith respect to the gold markers.
Results: The whole procedure was performed in 3 hours. On average 15.7
(1221) needles were used, prostate volumes varied from 20 to 60 cc. No
shifts of the implant with respect to the goldmarkers were observed. The
V100 equalled 97% (SD 2.4) of the prescribed dose for the PTV. Concerning
the organs at risk: D1cc of the rectum was 64% (SD 6) of the prescribed
dose. The maximum urethra dose is 126% (SD 5) on average, with the highdose in the extra margin.
Conclusions: An efficient new method to perform a one-stop single-fraction
HDR-boost to the prostate is presented. Dosimetry is well within the recommended range.

703 poster
COMBINED RADIOTHERAPY OF PROSTATE CANCER: HDR BOOSTVS LDR BOOST.
I. Albitskiy1 , A. Vinikovetskaya2
1
RUSSIAN S CIENTIFIC C ENTRE FOR R OENTGEN -R ADIOLOGY, Departmentof Radiation Oncology Radiological Sciences/Radiology, Moscow, RussianFederation
2
RUSSIAN S CIENTIFIC C ENTRE FOR R OENTGEN -R ADIOLOGY, departmentof CT, Moscow, Russian Federation

Purpose: To compare different combined irradiation techniques of prostatecancer treatment on effectiveness, frequency and expressiveness of irradiation damages.
Materials: We studied the results of treatment in two groups of patients.
Group 1 - 56 patients after combined irradiation with LDR boost, group 2 45 patients after combined irradiation with HDR boost. Brachytherapy was
the first part of treatment with additional EBRT in both groups. All patientsare standard by age, stage (T2-3N0M0) of disease and prognostic (intermediate and poor) factors. The median follow-up is 29 months. The median ageof patients is 64 years.
Results: The 3-years BFFS is no significantly higher in the HDR group86,6±5,0% vs. 91,1±4,7%, and there were no loco-regional relapse in thegroup 2, versus 4 2 local, 2 pelvic lymph node metastasis in LDR group. Late
irradiation damages in groups 1 and 2: rectitis 48,9±4,3% vs. 37,7±4,1%,
grade 2 - 28,6±3,7% vs. 13,33±3,9%, cystitis 46,2±2,6% vs. 44,4±2,9%,
grade 3 - 8,9±3,2% vs. 4,4±2,8%. The differences in irradiation damage
expressiveness are significant in two groups.
Conclusions: So, we consider combined irradiation technique with HDR
boost more preferable in prostate cancer patients because of better results
and lower complication level.

702 poster
COMBINED HDR BT AND 3D-CRT IN INTERMEDIATE AND HIGHRISK PROSTATE CANCER PATIENTS: A DOSE ESCALATIONMETHOD
O. Santa Cruz1 , C. Marques de Jesus1 , V. Mendonça1 , J. Melich-Cerveira2 ,G. Marcelino2 , I. Monteiro-Grillo1 3
1
H OSPITAL DE S ANTA M ARIA, Serviço de Radioterapia, Lisbon, Portugal
2
I NSTITUTO DE M EDICINA M OLECULAR , FACULDADE DE M EDICINA DAU NIVERSIDADE DE L ISBOA, Lisbon, Portugal
3
FACULDADE DE M EDICINA DE L ISBOA, Lisboa, Portugal
Purpose: The aim of this study is to evaluate the effect of escalating thedose on intermediate and high risk prostate cancer patients (pts) treated withcombined high-dose-rate brachytherapy (HDR-BT) and 3D C-external beam
radiotherapy (EBRT) vs the associated risk of complications
Materials: Data from 120 pts with intermediate and high risk prostate adenocarcinoma treated consecutively from January 2005 to December 2009 wereanalyzed. Median age was 65 years (47-76). Two different fractionation protocols were used according to patient collaboration: Group 1 (HDR-BT: 9,5
Gy /1 fraction, followed by EBRT: 60 Gy/ 30 fractions, biological effect: 89,9):83 pts; Group 2 (HDR-BT: 19 Gy/2 fractions/1 implant, followed by EBRT:46
Gy/23 fractions, biological effect: 105,7Gy ): 37 pts; 101 (84%) pts received
neo-adjuvant and/or adjuvant androgen deprivation. Toxicity was scored by
the Radiation Therapy Oncology Group morbidity grading scales. PSA relapse was defined according to the Phoenix consensus.
Results: With a median follow-up time of 31 months (range 7-66) for thewhole group, a specific survival of 100% was observed. Five pts died withno evidence of disease, 1 pt is alive with bone metastases. Seven pts hada biochemical recurrence and 1 patient didn’t respond to treatment (lowest
nadir was 4,5 ng/ml at 2,5 years). No significant difference on the 3 years
biochemical control for Group 1 and 2 was observed. Late gastro-intestinal
toxicity (GI) grade 1 and 2 was observed: 24% for Group 1 and 8.6% forGroup 2 (p=0,05). No grade 3 and 4 late GI toxicity in Group 1 and 2 pts.
Four pts from Group 1 had late grade 3 and 4 genito-urinary toxicity (GU).
In the group of pts who did not underwent hormonal therapy 31,6% had not
erectile dysfunction.
Conclusions: The association of HDR-BT and EBRT is currently used inmany centers to escalate the dose, however without any consensus about
dose and fractionation. This study addresses the efficacy of these two protocols with regards of biochemical control. Late toxicity was significantly reduced compared with what has been observed with 3D-C EBRT alone. However, pts from group 2 had a significant reduced late GI and GU toxicity.

704 poster
CT-BASED PROSTATE BRACHYTHERAPY TREATMENT PLANS
SHOW LOWER TARGET COVERAGE WHEN EVALUATED ON MRIANATOMYA. Dinkla1 , B. Pieters1 , H. van der Grient1 , N. van Wieringen1 , K.
Koedooder1 , R. van der Laarse2 , A. Bel1
1
AMC, Radiotherapy, Amsterdam, Netherlands
2
Q UALITY R ADIATION T HERAPY, Zeist, Netherlands
Purpose: For brachytherapy treatment planning in prostate cancer, accurate
definition of prostate and organs at risk (OARs) is required. Delineation of
the prostate is more accurate on MRI than on CT images. Despite the lower
visibility of the prostate boundaries, CT is mainly used for treatment planningof PDR/HDR prostate brachytherapy. This is because it is widely available
and known to visualize the location of implanted catheters accurately. By
also defining the contours on MRI, the effect of using CT-based contours on
the actual treatment can be investigated. The aim of this study is to assess
the impact of using CT on relevant DVH parameters by calculating DVHs fromCT and MRI anatomy.
Materials: In this retrospective study, post-implant CT and MRI image dataof 13 patients were used to delineate the prostate and OARs. The implanted
catheters (typically 12) were reconstructed on CT. An experienced planner
created treatment plans based on the CT structure set. DVHs of all organs(CT and MRI) were calculated to study the relevant parameters (V100, D90,
rectum V80, urethra V140) that define the quality of the treatment plan.
Results: We detected a statistically significant lower target coverage (definedas V100%) when the CT-based treatment plans were evaluated on the actual
target (i.e. MRI contours). Also, D90 on MRI appeared to be lower than theD90 on CT. Finally, doses to OARs delineated on MRI were on average higher
than doses to OARs delineated on CT (Table I).

C. Hoekstra2
RISO, Medical Physics, Deventer, Netherlands
2
RISO, Radiation Oncology, Deventer, Netherlands

1

Purpose: To present the introduction of an one-stop single fraction HDR
boost using (1) TRUS to contour the prostate and (2) in-room C-Arm ConeBeam CT (CBCT) to reconstruct needle-positions.
Materials: Since February 2010 28 Patients with cancer of the prostate eligible for combined therapy were enrolled in this new protocol. For the ex-

Conclusions: Evaluation of CT-based treatment plans on the MRI anatomy
showed decreased V100 and D90, and increased rectum V80 and urethra
V140. We found that the values of DVH parameters are worse than expected

S 281

from CT-based planning. We conclude that using CT for planning increases
the risk of treatment errors. Therefore, we recommend using MRI for prostatebrachytherapy treatment planning.

S 282B RACHYTHERAPY: P ROSTATE C ANCER

B RACHYTHERAPY: P ROSTATE C ANCER

705 poster
DOSE VOLUME HISTOGRAMS IN PATIENTS TREATED IMAGE
GUIDED SELECTIVE (DIL) HDR BOOST TO THE PROSTATE
E. Vigneault1 , R. Apardian Manougian1 , E. Chevrette2 , M. C. Lavallée1 , S.
Aubin1 , A. G. Martin1 , L. Beaulieu3
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Département de Radio-Oncologie, Quebec, Canada
2
CHUQ-CHUL, Department of Radiology, Quebec, Canada
3
C ENTRE DE RECHERCHE EN CANCEROLOGIE DE L’ UNIVERSITE L AVAL,
Quebec , Canada
Purpose: The purpose of this study is to describe Doses /Volumes Histograms obtained in patients treated with selective DIL (dominant intraprostatic lesion) HDR boost to the prostate.
Materials: Since December 2009 MRI (Magnetic Resonance Imaging)/MRS(Magnetic Resonance Spectroscopy) and correlation with the biopsy to define
the DIL for the dose escalation in the prostate cancer. All the patients wereintermediate risk prostate cancer. And none received androgen deprivation
therapy.13 patients received HDR boost (15Gy+3Gy in the DIL) in one fraction using inverse planning with simulated annealing (IPSA) for their localized
prostate cancer after 40-44 Gy of EBRT. Several dosimetry parameters wereanalyzed. For prostate (target) P_D10, P_D50, P_D90, P_V100, P_V150,
P_V200 and Homogeneity Index (HI) were available. For urethra, U_D10,
U_D50, U_D90, U_V100, U_V125, U_V150 were available. For bladder,
B_D10, B_D50, B_D90, B_V50, B_V100, B_V150 were available. For rectum, R_D10, R_D50, R_D90, R_V50, R_V75, R_V100, R_V150 were alsoavailable and D2cc, D5cc.
Results: The mean P_V100 was 93.32% (95%CI 91.02-95.96), P_V150 was
27.46% (95%CI 19.21-36.4) and P_V200 was 9.77% (95%CI 7.14-13.1) respectively. The U_V100 were 81.2% (95%CI 70.1-91.6) and U_V150 were0.03% (95%CI 0-0.2) respectively. The B_V50 were 8.06 %( 95%CI 4.0111.4) and B_V100 in 0.04% (95%CI 0.05-0.2) respectively. The R_V50,
R_V75 and R_V100 were 12.26 (95%CI 6.07-22.02), 1.86 (95%CI 0.533.12) and 0.005(95%CI 0.00-0.004) respectively. In the Rectum the valuesof D2cc 10.2(8.95-11.3) Gy and D5cc 8.4 (7-9.3) Gy. Homogeneity Index(HI) were 0.70(0.60-0.80)The DIL; D90 was 18.97(range17.7-20.04), V120
was 95.73(86.2-99.13) and V 150 was 40.95(18.3-64.5) These DVHs parameters compared favorably with those obtained in patients treated with HDR for
prostate cancer without selective boost to DIL.
Conclusions: The use of image guided (MRS) selective HDR boost to DIL
with IPSA is feasible while keeping DVHs comparable to standard prostate
HDR bracytherapy. Increases the dose to the DIL 120-150% preserving
prostate coverage. Longer follow-up is needed to evaluate the benefit andoutcomes.
706 poster
EFFICACY, TOXICITY AND DOSIMETRIC ASPECTS OF HDR
BRACHYTHERAPY IN PROSTATE CANCER PATIENTS :4 YEARSEXPERIENCE
T. Filipowski1 , K. Dorota1 , S. T. Anna1 , N. Wiktor2 , P. J. Barbara2
1

B IALOSTOCKIE C ENTRUM O NKOLOGII, Department of Radiotherapy,
Bialystok, Poland
B IALOSTOCKIE C ENTRUM O NKOLOGII, Department of Medical Physics,
Bialystok, Poland

2

Purpose: To analyze efficacy, toxicity profile and dosimetric aspects of radical
brachytherapy HDR +/- teleradiotherapy in prostate cancer patients.
Materials: Between December 2006 and December 2010 -128 patients(pts) with prostate cancer (T1 T2c) underwent conformal HDR brachytherapy(HDR-BRT) with a temporary implant. The mean age of pts was 69 years,
while mean PSA 12,069 [ng/ml]. Gleason score was observed from 3 to
7 and most of the patients received androgen deprivation. 60 patients received 30 Gy in 2 fractions of HDR brachytherapy (21 days interval) and weretreated to a dose of 30 Gy in 15 fractions with 3D external beam radiotherapy (3 to 5 fields) on to the prostate region. 68 patients were treated with
exclusive HDR-BRT 45 Gy in 3 fractions (21 days interval). HDR brachytherapy was delivered using an Iridum-192 source (MicroSelectron, Nucletron)and treatment planning system: SWIFT 2.11.8 and Oncentra Prostate 3.0.9
real-time treatment planning software SWIFT incorporates inverse planning
optimization. Dose volume constraints for this inverse planning system included: prostate V 100 ≥95 %, maximal urethral dose ≤ 120% and averagerectal dose ≤85% of the prescription dose. Patient were monitored weekly
during radiotherapy and 1, 3, 6, 9,and 15 months after the end of treatment
and then at three months interval. Follow-up visit included clinical examination and PSA value assessment. The acute toxicities were graded according
to the EORTC/RTOG scales.
Results: Median follow up was 18 months with 95% disease-free survival
rate. The most common urinary symptoms were: urinary urgency, urinary
frequency, dysuria and nocturia in both treatment options. The rectal symptoms (rectal urgency, frequency and tenesmus) were rare. No grade 3 and 4
acute toxicities were recorded. One death case was reported during combine
treatment. Overall survival data need longer follow-up.

Conclusions: HDR-BRT is a valid treatment modality for patients with localized prostate cancer. HDR-BRT have an important role in achieving dose
escalation for the radical treatment of prostate cancer patients. The treatment
was well tolerated by majority of patients with acceptable degree of acute toxicities.

Results: Treatment was well tolerated with less than 10% of patients requiring urinary catheterization and grade ≤3 genitourinary and gastrointestinal
toxicity rates of <5%. The 5-year actuarial biochemical no evidence of disease (bNED) survival rate and the 5-year overall survival rates were 92% and
86% respectively. With a median follow-up of 48 months there have been
27 PSA failures. There have also been 33 deaths, 5 due to prostate cancerand 17 to other malignancies. Of the latter, lung and GI primary tumours
accounted for over 50 % of these deaths.
Conclusions: With a median follow-up of 48 months, prostate brachytherapy
using a permanent I125 implant is an effective treatment option for patientswith low risk adenocarcinoma of the prostate. It is well tolerated with acceptable morbidity and favourable long-term PSA failure free rates.

707 poster
EVOLUTION OF 15 YEARS IN INVERSE PLANNED HIGH ACTIVITY
I-125 SEEDS PROSTATE BRACHYTHERAPY AT L’HOTEL-DIEU DE
QU É BEC: AN UPDATE ON CANCER CONTROL.
A. G. Martin1 , E. Vigneault1 , W. Foster1 , S. Aubin1
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Department of Radiation Oncology, Quebec, Canada
Purpose: To review our disease free survival in prostate I-125 brachytherapy
through our evolution in technology over the past 15 years.
Materials: We analyzed prospectively collected data from 1198 patients,
which had over 24 months of PSA follow-up. We started doing prostatebrachytherapy in 1994 using high activity seeds with an inverse-planning simulated annealing (IPSA) dosimetric approach. Since year 2004 we used an
intra-op technique which build the seed sequence and robotically deliver theseeds and then retract the loading needle. In the year 2003-4 needles werebuild intra-op but seed loading and needle retraction were done manually.
Prior to that time, needles were pre-loaded. Year 2000-2 consists in ourincrease in procedure numbers and more stringent application of selection
criteria and CT dosimetric evaluation. The years 1994-2000 corresponds tothe initial phase prostate implantation at the Hotel-Dieu de Quc. Biochemicaldisease free survival (BDFS), genito-urinary (GU), gastro-intestinal (GI) andsexual toxicity (SxT) are reported using patient based questionnaires.
Results: The median age of our population at the procedure is 64,13 years
old and the tumor risk level is low in 83,8% of the cases, intermediate in
13,2% and high in 3%. 92% of the patients had PSA < 10 ng/mL, Gleason
score were < 7 in 99,1% of the population and, Stage of the disease was T2Aor less in 91,2% of the patients. Of all the population, 95,9 % are disease
free @ 61,4 months median for PSA follow-up. Patients were absolutely freeof GI symptoms in approximately 58,4 % @ more then 6 months post treatment. Less then 5,2% reported regular GI symptoms. Using IPSS standard
questionnaire in the late phase (> 6 months post implantation), 27,4 / 49,3
/ 23,3 % if the patients reported mild, moderate and severe urinary symptoms. Erectile dysfunction was reported in 19,8% of our patients in the latephase. Throughout time, we modify our implantation technique and the results followed. The BDFS @ 5 years is 94,5% - 97,45% - 97,76% - 99,08%
respectively with correlated for year < 2000, 2000-02, 2003- 04 and > 2004.
Conclusions: Biochemical disease specific survival was increased throughtime and procedure evolution. Our side effects were also kept low by thesame way. This study suggests that the technique improved was worthwhile
for our patients.
708 poster
EXPERIENCE OF IMAGE-GUIDED HDR BRACHYTHERAPY FOR
LOCALIZED PROSTATE CANCER WITH FAVORABLE PROGNOSTIC
FACTORS IN THE REPUBLIC OF BELARUS
E. L. Slobina1 , S. Polyakov2
1
N.N. A LEXANDROV N ATIONAL C ANCER C ENTER OF B ELARUS, Division ofRadiotherapy, Minsk, Belarus
2
N.N. A LEXANDROV N ATIONAL C ANCER C ENTER OF B ELARUS, Departmentof Oncourology, Minsk, Belarus
Purpose: To report results of treatment for localized prostate cancer withfavorable prognostic factors using 192 Iridium HDR interstitial image-guided
brachytherapy
Materials: Between February 2007 and October 2010 a total of 27 previously
healthy patients, Table 1, with favorable prognostic factors (Gleason score ≤7, PSA ≤ 10 ng/ml) and biopsy proven adenocarcinoma. HDR brachytherapy
was performed by conformal image-guided transperineal HDR brachytherapy
with real-time planning.The total dose was 34.5 Gy/3 fractions (1st day twice
a day with 4-6 hours interval between fractions, after 2 weeks gap 1 fraction),
the dose per fraction was 11.5 Gy. 5 patients received temporary androgendeprivation starting 2-9 month before brachytherapy.

S 283

710 poster
FOCAL BRACHYTHERAPY FOR PROSTATE CANCER : A PILOT
STUDY
J. M. Cosset12 , G. Wakil1 , N. Pierrat1 , X. Cathelineau2 , V. Marchand1 , G.
Vallancien2
1
I NSTITUT C URIE, Paris, France
2
I NSTITUT M UTUALISTE M ONTSOURIS, PARIS, France

Results: The median follow-up was 16 months (range 3 - 44 months). There
was no evidence of distant metastases, biochemical or clinical failure. All 27
patients experienced some degree of acute urinary toxicity, Table 2. However,chronic reactions are absent. The median first post-treatment PSA was 0.81
ng/ml (range 2.8-0.04 ng/ml).

Purpose: Permanent implant prostate brachytherapy (using Iodine-125
seeds) is now recognized as one of the standard therapies for low-risk localized prostate cancer. For strictly selected patients, focal therapy is nowadays
increasingly proposed to limit toxicity and permit easier salvage in case of
failure. Brachytherapy, which is able to treat a well-defined partial prostate
volume at a well-defined dose level, appears to be particularly well adapted
to focal prostate therapy.
Materials: At the Institut Mutualiste Montsouris (IMM), focal brachytherapy
was initiated in February 2010, according to a protocol approved by the IMM
ethics committee, with all patients signing an informed consent. Patient selection is based on (at least) two series of prostate biopsies and on a highresolution MRI. Only patients with very limited and localized tumors, according to strict criteria, were selected for the procedure. The technique is directly
derived from the "real-time" procedure (already published by our team) with
the implantation of "free" Iodine-125 seeds, with dynamic dose calculation(continuous feedback as per the real positioning of each seed). We chose todeliver to the focal volume the dose usually recommended by GEC-ESTRO
for the whole prostate (145 Gy).
Results: Wrong block type.
Conclusions: Focal treatment by brachytherapy is easily feasible with apparently little acute toxicity. Further investigation is needed to assess the resultsin terms of tumor control and toxicity.
711 poster

Conclusions: Interstitial HDR brachytherapy can be an useful and effective treatment approach in certain cases of prostate cancer especially as
monotherapy for treatment of patients with favorable prognostic factors. The
treatment results in low toxicity and in excellent functional results. It is a very
useful modality as alternative kind of treatment to a surgical approach andexternal beam irradiation.

HDR BRACHYTHERAPY AS MONOTHERAPY FOR EARLY STAGE
PROSTATE CANCER: ACUTE TOXICITY
S. Aluwini1 , P. van Rooij2 , W. Kirkels3 , C. Bangma3 , I. K. Kolkman-Deurloo4
1
E RASMUS M EDICAL C ENTER R OTTERDAM, 2nd Radiotherapy Department,
Rotterdam, Netherlands
2
E RASMUS M EDICAL C ENTER R OTTERDAM, Radiation Oncology, Rotterdam, Netherlands
3
E RASMUS M EDICAL C ENTER R OTTERDAM, Urology, Rotterdam, Netherlands
4
E RASMUS M EDICAL C ENTER R OTTERDAM, Rotterdam, Netherlands

709 poster
FIVE-YEAR OUTCOME FOLLOWING PERMANENT INTERSTITIAL
BRACHYTHERAPY FOR LOW RISK PROSTATE CANCER
C. Springer1 , L. Skeates2 , S. Ozard3
1

W INDSOR R EGIONAL C ANCER C TRE, Windsor, Ontario, Canada
W INDSOR R EGIONAL C ANCER C TRE, Radition-Oncology, Windsor, Ontario,
Canada3
W INDSOR R EGIONAL C ANCER C TRE, Radiation Oncology Physics,
Windsor, Ontario, Canada
2

Purpose: To evaluate the 5-year biochemical disease-free outcome of patients with early stage adenocarcinoma of the prostate treated with prostatebrachytherapy as monotherapy using a permanent I125 implant at the Windsor
Regional Cancer Centre (WRCC).
Materials: This is a retrospective case study of 429 consecutive patients treated transperineal ultrasound-guided prostate brachytherapy between June 1999 and May 2009. All patients had a biopsy confirmed diagnosis of adenocarcinoma of the prostate and were treated with prostatebrachytherapy to a prescribed dose of 144 Gy. The median age at presentation was 66 years (range, 4686 years). The median follow-up was 48 months(range 8-50 months). Follow up was calculated from the date of the implant.
Four hundred and sixteen (97%) patients presented with low risk disease,defined by the following: PSA ≤10, T-stage ≤2b, and Gleason Score ≤6.
Biochemical disease-free survival was defined using the Phoenix definition(PSA > nadir + 2).

Purpose: The use of HDR brachytherapy as monotherapy for early stage
prostate cancer patients is increasing worldwide. We report our experience
regarding the acute toxicity.
Materials: Between September 2007 and October 2010 a group of 78 patients underwent HDR monotherapy as treatment for their biopsy proven earlystage prostate cancer with favorable prognostic factors (stage ≤ T2b, Gleason score (GS) ≤ 6, initial PSA (iPSA) ≤ 15 ng/ml). HDR brachytherapy
was performed using US guided implantation and CT based treatment planning (according to R&O 2004; 73; 73-77). The total dose was 38 Gy in 4
fractions within 36 hour. Our constraints for target and organ at risk are:prostate D90>9.5 Gy, prostate V100>90%, rectum V80 < 1 cc, bladder V80< 2 cc, urethra V120 < 5%.Validated questionnaires (IPSS, EORTC/RTOG)
were prospectively administered to all patients before and at 0.5, 1, 2, 3, 6
months after treatment and were evaluated in this report.
Results: Median age of patients was 68 years (range 51-79), 22 patientsclassified with stage T2a and 56 T1c disease, one patient had GS of 5, andall others had GS of 6. Median iPSA was 7.1 (range 1.4-13 ng/ml). Median number of needles was 17 (range 12-23). Median pretreatment prostate
volume (ultrasound) was 33 cc (range 15-55 cc). Median post-implantation
prostate volume on the CT-scan was 63 cc (range 27-86 cc). The treatment
was well tolerated. No operation complications were reported. The median
D90 (dose delivered to 90% of the prostate) was 10.1 Gy (range 9.5-10.8
Gy). The median V100 (the percentage of the prostate that received the prescribed dose) was 94% (range 89.9-98.6). The constraints of the bladder,
rectum and urethra were well met. Seventy four patients have 3 months FU

S 284B RACHYTHERAPY: P ROSTATE C ANCER

B RACHYTHERAPY: P ROSTATE C ANCER

and 68 patients 6 months. Acute toxicity evaluated by IPSS score, with a
median IPSS-score of 5 (range 0-20) before treatment, showed a median increase of total score of 5 (mean IPSS-score 12) and 3.5 (mean 11) after 3 and6 months respectively. The EORTC/RTOG toxicity scales show for rectal anddefecation symptoms mild symptoms (grade 1) in 21%, 7%, 10%, 3% and
3% of patients after 2 weeks, 4 weeks, 8 weeks, 3 months and 6 months respectively. Moderate (grade 2) symptoms have been seen in 4%, 3% and 0%
after 1, 3 and 6 months respectively. No grade 3 symptoms have been registered.Urinary toxicity (grade 1) was seen in 53%,46%,22%, 11%, 21%, while
grade 2 urinary toxicity was seen in 11%, 6%, 3%, 4%, 0% of patients after
2, 4, 8 weeks, 3, 6 months respectively. Five patients needed a temporally
catheter (grade 3 toxicity) shortly after the treatment.There is no biochemicalrecurrence registered till now, the mean PSA is 1.1 and 0.9 after 12 and 24
months respectively.
Conclusions: This regimen of CT based planning HDR brachytherapy as
monotherapy for early stage prostate cancer has been well tolerated withminimal acute toxicity in combination with excellent dose coverage of theprostate. Long term disease control results will be reported in the future.
712 poster
HIGH-DOSE RATE BRACHYTHERAPY AS ONE-DAY MONOTHERAPY DELIVERED IN 2 FRACTIONS FOR FAVORABLE-RISKPROSTATE CANCER. PRELIMINARY TOXICITY DATA.
M. Ghilezan1 , A. Martinez1 , D. Krauss1
1
W ILLIAM B EAUMONT H OSPITAL, Department of Radiation Oncology, Royal
Oak, USA
Purpose: HDR-BT as monotherapy was initiated at William Beaumont Hospital in 1997 as a single implant and four fractions for a total dose of 38 Gy
BED1.5= 266, delivered over 36 hours. In an effort to shorten the treatment
time and hospital stay, an HIC-approved study was started in 2005, consisting of a single implant and 2 fractions (12Gy x 2) for a total dose of 24 Gy
BED1.5=208, subsequently increased to 27Gy (13.5Gy x 2) BED1.5=261 delivered over one day. We report the acute and early chronic genito-urinary(GU) and gastrointestinal (GI) toxicity
Materials: From 3-1999 to July 2010, 163 patients with favorable or low
intermediate-risk prostate cancer have been treated with the HDR-BT 2fraction protocol. The first 100 patients were part of a HIC-approved study. 94
patients had a minimum follow-up of 6 months and were included in this analysis. All patients were clinical stage ≤T2b, Gleason score (GS) 2 to 7 (3+4)
with <50% of (+) cores and PSA ≤12 ng/ml. Ultrasound guided HDR-BT with
online real-time dosimetry was employed. The prescription dose was 24Gy in
the first 50 patients and 27Gy for the next 50 patients of which 44 patients areincluded in this report. The dosimetric goals and constraints were: prostate
V100>95%, urethra V100 <95%, V115<3%, rectum V75<1%, and were thesame for the two dose groups. All patients met the dosimetric requirements.
Toxicity was scored according to NCI CTAE v3 criteria. The highest toxicity
score encountered were reported.
Results: Median follow-up was 17 months (range 6-40.5 months). Medianpatients’ age was 63. The majority of patients had grade 0 acute GU toxicity. Grade 2 acute GU toxicity was mainly frequency/urgency (13%), dysuria(5%), hematuria and dribbling/hesitancy (2%). there was no grade 3 acute
GU toxicity and none of the patients was discharged with a Foley catheter.
There were no grade 2 or 3 acute GI toxicities. 8% of patients experienced
mild grade 1 diarrhea in the first week, likely related to prophylactic antibiotics post-procedure. There were no other acute GI toxicities. Most common
chronic toxicity was urinary frequency/urgency grade 2 in 16% of patients followed by dysuria in 4% of patients. 2 patients had grade 2 rectal bleeding andone grade 4, whom required laser treatment. No other grade 2-4 GI toxicities
were recorded.
Conclusions: Favorable-risk prostate cancer patients treated with a single
implant HDR-BT to 24Gy-27Gy in 2 fractions delivered in one day and 6 hours
interval, have an excellent tolerance with minimal acute and chronic toxicities.
Longer follow-up is needed to reliably assess thechronic toxicity profile of thisconvenient treatment modality as well as its clinical outcome.
713 poster
HIGH-DOSE-RATE BRACHYTHERAPY COMBINED WITH EXTERNAL BEAM RADIOTHERAPY FOR LOCALIZED PROSTATE CANCER:
CLINICAL PREDICTIVE FACTOR FOR OVERALL, DISEASESPECIFIC, AND BIOCHEMICAL RELAPSE-FREE SURVIVAL
S. Kariya1 , I. Yamasaki2 , K. Tamura2 , T. Shuin2 , A. Nishioka1 , Y. Ogawa1
1

KOCHI M EDICAL S CHOOL, Department of Diagnostic Radiology Radiation
Oncology, Kochi, Japan
2
KOCHI M EDICAL S CHOOL, Department of Urology, Kochi, Japan

Purpose: The aim of this study is to determine what kind of clinical factors
were predictive for overall survival (OS), disease-specific survival (DSS), andbiochemical relapse-free survival (bRFS) of prostate cancer (CaP) patientstreated with high dose rate-brachytherapy (HDR-BT) combined with externalbeam radiotherapy (EBRT).

Materials: Between July 1999 and September 2007, 15, 51 and 41 patients
considered as low-risk group (stage < or = T2a, PSA < or = 10 ng/ml, andGleason score (GS) < or = 6), intermediate-risk group (stage = T2b, 10 <PSA < or = 20 ng/ml, or GS = 7), and high-risk group (stage > or = T2c,
PSA > 20 ng/ml, or Gleason score > or = 8), respectively, were treated with
HDR-BT followed by EBRT at Kochi Medical School Hospital in Japan. Patient age ranged from 55 to 81 years (median 71). Forty-two patients hadreceived neoadjuvant hormonal therapy, which was stopped at the beginningof radiotherapy in all casesBetween July 1999 and September 2007, 15, 51
and 41 patients considered as low-risk group (stage < or = T2a, PSA < or =10 ng/ml, and Gleason score (GS) < or = 6), intermediate-risk group (stage =T2b, 10 < PSA < or = 20 ng/ml, or GS = 7), and high-risk group (stage > or =T2c, PSA > 20 ng/ml, or Gleason score > or = 8), respectively, were treatedwith HDR-BT followed by EBRT at Kochi Medical School Hospital in Japan.
Patient age ranged from 55 to 81 years (median71). Forty-two patients hadreceived neoadjuvant hormonal therapy, which was stopped at the beginningof radiotherapy in all cases.Patients were treated with EBRT to 39-45 Gy in
13-25 fractions, and HDR-BT to 18 Gy in 2-3 fractions for prostate. Adjuvant hormonal therapy was not performed until biochemical failure or clinicalrecurrence became apparent. PSA failure was defined as the Phoenix definition of nadir + 2ng/mL. OS, DSS, and bRFS rates were estimated using
the Kaplan-Meier method. Cox proportional hazards regression analysis wasused for univariate and multivariate analyses examining these factors in relation to bRFS: clinical T stage, initial PSA level, GS and use of neoadjuvant
hormonal therapy
Results: The 5-year OS rate in low-, intermediate- and high-risk group were100%, 100%, and 90.1%, respectively. The 5-year OS rate did not differ statistically significantly between three risk groups. The 5-year DSS rate in low-,intermediate- and high-risk group were 100%, 100%, and 97.4%, respectively. The 5-year DSS rate also did not differ statistically significantly between
three risk groups. The 5-year bRFS rate in low-, intermediate- and high-risk
group were 100%, 97.9%, and 83.7%, respectively. The 5-year bRFS rate inhigh-risk group was statistically inferior to that in intermediate-risk group (p =0.0206). On univariate and multivariate analyses, clinical T state remained
an independent predictor of bRES. None of initial PSA level, GS, or use ofneoadjuvant hormonal therapy was not predictive factor for bRFS of CaP patient with HDR-BT combined with EBRT.
Conclusions: Clinical T3 CaP carries a worse bRFS than clinical T1-2 Cap.
However, T3 Cap Cap had excellent overall and disease-specific survival
rates.
714 poster
HYPOFRACTIONATED EXTERNAL BEAM RADIOTHERAPY PLUS
HIGH-DOSE-RATE BRACHYTHERAPY FOR INTERMEDIATE ORHIGH RISK PROSTATE CANCER: ANALYSIS OF MEDIUM-TERM
URINARY TOXICITY PRECEPTIVE FACTORS AND BIOCHEMICALCONTROL
A. C. A. Pellizzon1
1
H OSPITAL A.C. C AMARGO, Department of Radiation Oncology, Sao Paulo,
BrazilPurpose: The best management of localized and locally advanced prostatecancer remains controversial, but there are evidences that for patients considered of unfavorable outcome dose escalation radiotherapy has a significantly
better outcome. The rational for the use of tumor dose escalation is that itshould hypothetically overcome radioresistance of tumor clonogens seen atconventional dose levels. Studies of the radiobiology of prostate cancer (PCa)also suggest that it may be more susceptible to large fraction sizes comparedwith standard fractionation of external beam radiation. Hence the the association of hipofractionated conformal tri-dimensional radiotherapy (hEBRT) and
HDR for dose escalation in the treatment of PCa would led to better, or atleast equal biochemical control rates (bC) when compared to conventionaldose fractionation, with less time spent for treatment for the treatment.
Materials: Between 2005-2009 a total of 39 unfavorable patients were treatedin a phase I-II trial for dose escalation with high-dose rate (HDR)- 30Gy/4
fractions BID/2 implants and hipofractionated conformal/tri-dimensional radiotherapy (hEBRT)-45Gy/3Gy fractions in 3 weeks, at Hospital AC Camargo,
Sao Paulo, Brazil.
Results: Median age of patients was 69 years old. With a median follow
up of 42.5 months the highest RTOG acute and late severe genitourinary
toxicity (GU-TX) were grade 3 in 2 patients (5.1%) and 1 (2.6%) patients,
respectively. No predictive clinical or dosimetric factor related to acute GUTX was found. Regarding late GU-TX, prostate volume > 45cc (p=0.024),<11 needles per implant (p=0.038) and urethral dose >130% of prescribed
dose (p<0,001) were statistical significant predictive factors. On multivariate
analysis the only predictive factor for late GU-TX was urethral dose >130%,p=0.017 (95%CI1.39-29.49), HR-6.4. The actuarial overall survival, biochemical control and disease specific survival rates at 3.5-years were 92.0%,
87.6% and 96.9%, respectively.
Conclusions: HDR combined to hEBRT is well tolerated in the short andmedium term. Acute toxicity was minimal and improved outcomes in terms of
reduced late toxicity can be achieved using at least 11 needles and prostate
volumes up to 45cc to be implanted. The maximum urethral dose should be
kept bellow 130% of prescribed dose.

715 poster
INTEROBSERVER VARIATION IN MRI AND CT BASED CONTOURING FOR PROSTATE CANCER
B. Segedin1 , J. But Hadzic1 , P. Rogelj2 , M. Sesek1 , H. B. Zobec Logar1 , B.
Kragelj1 , P. Petric1
I NSTITUTE OF O NCOLOGY L JUBLJANA, Ljubljana, Slovenia
FACULTY OF M ATHEMATICS , N ATURAL S CIENCES AND I NFORMATIONT ECHNOLOGIES, Koper, Slovenia

1

2

Purpose: Capability for conformal dose escalation, afforded by brachytherapy (BT), exceeds any other radiotherapy modality. Even minimal contouring
variation may result in significant dose delivery uncertainties, undermining
overall treatment efficacy. We aimed to quantify feasibility of delineation anddegree of interobserver variation in MRI and CT based contouring for prostate
BT.
Materials: At the Institute of Oncology Ljubljana, intermediate and high risk
prostate cancer patients are treated with pelvic external beam radiotherapy,
followed by MRI-based PDR BT boost. After ultrasound-guided needle insertion, pelvic MRI is obtained for planning. Three fractions of 6 Gy (10 hinterfraction interval) are applied to gland periphery. Prior to 3rd fraction, CT
is performed to quantify implant displacement. In this study, prostate wasoutlined by 4 radiation oncologists in 5 consecutive patients (test contours)on MRI and CT. Ability to discriminate gland apex, base and lateral borders
on both modalities was scored by each observer, utilizing a 3-tiered scale(1-poor, 2-moderate, 3-excellent). Test contours were compared to referencedelineations, representing a consensus of two senior radiation oncologists.
Dedicated software, developed ar our department, was used to perform quantitative volumetric and topographic analysis of contouring variation for bothmodalities.
Results: Mean ability to discriminate apex, base and lateral prostate borders
was higher on MRI (2.5, 2.5 and 2.8, respectively), when compared with CT(1.4, 1.6 and 2.0, respectively). Sizes of contoured volumes were 41 ± 15
and 45 ± 14 cm3 on MRI and CT, respectively. Ratio between common andencompassing volume of reference and test contours was higher for MRI thanCT (0.83 ± 0.04 vs. 0.69 ± 0.05 mm). Radial inter-contour distances were
smaller on MRI than CT (1.5 ± 0.4 vs. 3.5 ± 0.7 mm). Maps of variation
distribution were created. Variations were most pronounced in apical region
for both modalities. Mean cranio-caudal distance between reference and test
contours was smaller on MRI (base: 0.8 ± 1.6 mm; apex: 1.9 ± 2.7 mm)
when compared with CT (base: 2.9 ± 2.1 mm; apex: 3.4 ± 2.6 mm).
Conclusions: MRI enables superior definition of outer prostate boundaries
when compared with CT. Using MRI, contouring variation and resulting dosedelivery uncertainties in temporary prostate BT can be minimized.
716 poster
INTERSTITIAL BRACHYTHERAPY (IB) FOR LOCALIZED PROSTATECANCER (LPC): THE TRENTO EXPERIENCE.
G. Fellin1 , S. Mussari1 , C. Divan2 , F. Coccarelli2 , O. Caffo3 , F. Ziglio4
1
O SPEDALE S ANTA C HIARA, Radiotherapy, Trento, Italy
2
O SPEDALE S ANTA C HIARA, Urology, Trento, Italy
3
O SPEDALE S ANTA C HIARA, Oncology, Trento, Italy
4
O SPEDALE S ANTA C HIARA, Trento, Italy
Purpose: IB is a therapeutic option for radical treatment of LPC and thistherapy has been offered to selected patients (pts) in our Hospital from 2000.
The IB management has been performed by a dedicated Brachytherapy Pool
(BP) involving the departments of Radiotherapy, Urology, Medical Oncology,
and Health physics. The present report is aimed to retrospectively report theTrento experience.
Materials: From May 2000 to December 2008, we treated with IB a consecutive series of 409 pts with LCP. The IB consisted of I125 permanent implant
and was performed as exclusive treatment in 380 pts (with a delivered dose of
145 Gy) and as a boost treatment (with a delivered dose of 100 Gy) in association with 45-50.4 Gy external beam radiotherapy in 29 cases. A short-term
pre-IB hormonal therapy was performed in 153 pts. The median age was 66
yrs (range 49-78); the NCCN risk class was low, medium and high in 68%,
30% and 2% of the cases respectively. CT-based dosimetry at 4 weeks after
implant was used for post-planning evaluation. D90 and V100 were recorded
for each patient, along with other dosimetric parameters. The biochemical
relapse (BR) was defined according to the Phoenix ASTRO Consensus Conference recommendations. Side effects and quality of life (QL) were recorded.
Results: The prescribed D90≥100% and V100 ≥90% dose was achievedby 83% of the pts. A RTOG grade ≥2 urinary toxicity was observed in 15%of the cases with 2% requiring temporary use of catheter due to acute urinary
retention. Twelve pts (3%) showed a G1 rectal toxicity. Late grade ≥1 urinary
toxicity was observed in 10.5% of the pts with 2.5% requiring a TURP. After amedian follow-up of 55 months, the relapse rate was 11% with 8 pts (2%) developing a clinical relapse and 36 (9%) showing only a biochemical relapse.
The 5- and 10-yrs relapse free survival (RFS) was 92% and 79%, respectively. At this time, 30 pts dead (27 relapse free), with a 5- and 10-yrs overall
survival of 93% and 85%, respectively. Low-risk pts had better RFS compared
to intermediate-risk (5-y: 95% vs 88%; 10-y: 80% vs 73%; p: NS). Similarly,

S 285

pts with better dosimetric parameters (V100≥90% and D90≥100%) had better PFS compared to the others (5y: 95 vs 80%; p<0.05). QL outcomes of pts
treated until 2005 has been previously published (IJROBP 66: 3137, 2006).
A new prospective QL evaluation started from 2005 and is ongoing.
Conclusions: Our data reproduce the outcomes of larger published series.
In this view, IB may be considered as an effective treatment not only in
low- but also in intermediate risk LPC. Dosimetric quality parameters (D90
and V100) significantly influence biochemical outcome. The multidisciplinary
management of IB represents an added value in enhancing pts selection and
IB quality.
717 poster
INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY AS
MONOTHERAPY FOR EARLY STAGE PROSTATE CANCER : MEDIAN
8 YEAR RESULTS IN 319 PATIENTS
R. Mark1 , R. Akins2 , M. White3 , M. Nair2
1
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department for
Radiation Oncology and Experimental Cancer Research, Lubbock, Texas,
USA
2
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, USA
3
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department for
Radiation Oncology - section Quantitative Magnetic Resonance Imaging,
Lubbock, Texas, USA
Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for
prostate cancer using Low Dose Rate (LDR) and High Dose Rate (HDR)
technique has been reported with results comparing favorably to surgery andExternal Beam Radiation Therapy (EBRT). Often, HDR and LDR interstitial
implant is combined with EBRT. There is little published data on HDR alone.
We report our results with HDR alone.
Materials: Between 1997 and 2010, 319 patients with T1 and T2 localized
prostate underwent TRUS guided interstitial implant, under spinal anesthetic
or local anesthetic. There were no Gleason Score or PSA exclusions. No
patient received EBRT or Hormonal Blockade. Median Gleason Score was
7 (range : 4 to 10). Median PSA was 9.3 (2.7 to 39.8). Treatment volumes
ranged from 32 cm3 to 196 cm3 . Treatment volume included the prostate andseminal vesicles in all cases. Radiation Treatment planning was performed
using CT Scanning and the Nucletron Plato Treatment Planning System. Our
IRB protocol for HDR alone, has called for two HDR Implants, spaced 4 weeks
apart. The treatment volume received 2,250 cGy in 3 fractions prescribed to
the 100% Isodose line, given over 24 hours. A 2nd implant was performed
4 weeks later, delivering a further 2,250 cGy in 3 fractions, bringing the final
dose to the prostate to 4,500 cGy in 6 fractions. Urethral dose points (12-16)
were followed, and limited to < 105% of the prescription dose.
Results: With a median follow-up of 102 months (range : 6 months to 174
months), PSA disease free survival was 88.7% (283/319). Actuarial 8 year
PSA disease free survival was 86%. The actuarial 8 year PSA DFSs by risk
group, were 94% for low risk, 86% for intermediate risk, and 65% for highrisk. The procedure was well tolerated, with all patients having completed theprocedure. Acute and chronic complications were uncommon. Acute urinary
retention occurred in 5.0% (16/319) of the patients, requiring temporary insertion of an indwelling foley catheter. Urethral stricture requiring dilatation
has developed in 5.6% (18/319) of patients. Urinary stress incontinence has
occurred in 2.8% (9/319). RTOG late bladder toxicities were : 0% Grade 4,
0% Grade 3, and 2.8% (9/319) Grade 2. RTOG late rectal toxicities were :0.6% (2/319) Grade 4, 0% Grade 3, 1.0% (3/319) Grade 2, and 1.3% (4/319)
Grade 1.
Conclusions: Eight year results with HDR implant alone compare favorably
to EBRT, LDR +/- EBRT, and HDR + EBRT, both with regard to PSA disease free survival, and complications. HDR offers other advantages over
LDR, such as no radiation exposure to hospital personnel, no seed migration, greater dose flexibility and precision of radiation dose delivery. Larger
volumes can be treated with HDR. By omitting EBRT, bladder and rectal complications appear to be significantly reduced.
718 poster
INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY UNDERLOCAL ANESTHESIA FOR EARLY STAGE PROSTATE CANCER : A
REPORT OF 546 CASES
R. Hargrove1 , R. Mark1 , R. Akins2 , M. Nair3
1

J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Section of Radiobiology, Lubbock, USA
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Departments ofRadiation Oncology, and Imaging Research, Lubbock, Texas, USA
3
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, Texas, USA
2

Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for
prostate cancer using Low Dose Rate (LDR) and High Dose Rate (HDR)
techniques has been reported with results comparing very favorably to ex-

S 286B RACHYTHERAPY: P ROSTATE C ANCER

B RACHYTHERAPY: P ROSTATE C ANCER

ternal beam radiation therapy. TRUS interstitial implant of the prostate has
been traditionally performed under general or spinal anesthetic in an operating room. We report our results with a technique performed under local
anesthesia in a Department procedure room.
Materials: Patients with T1 and T2 localized prostate cancer were judged
to be candidates for TRUS guided interstitial implant. Conscious sedationconsisted of intravenous Morphine (12-22 mg), Versed (6-14 mg), and Ativan (0.5-2 mg), or intravenous Demerol (50-250 mg), Versed (3-12 mg), andAtivan (0.5-2 mg). Local anesthetic was given with a mixture of 1% Lidocaine, 0.25% Marcaine, 1:100,000 Epinephrine, and 4% Sodium Bicarbonate neutralizing solution (20-120 cc). Local anesthesia was given to a 5 x 5cm perineal area to a depth of 10 cm under TRUS guidance. The implants
were placed under mobile multi-plane prostate template (Radiation Therapy
Products Prostate Template) guidance using from 3 to 4 planes, and 12 to
22 needles. Needle spacing was 1.0 cm. The implant procedure included
sigmoidoscopy and cystoscopy.
Results: Between 2002 and 2010, 546 TRUS guided prostate implants were
performed under local anesthesia. Median implant time was 45 minutes(range : 30 to 150 minutes). HDR treatment was given using the Nucletron afterloading system. The implant volume received 2,250 cGy in 3 fractions prescribed to the 100% Isodose line, given over 24 hours. Urethral dose points(12-16) were followed, and limited to < 105% of the prescription dose. The
procedure was well tolerated, with all patients having completed the procedure. Four patients developed respiratory suppression, and required reversal
with Narcan. All recovered uneventfully. Otherwise, there have been no acutecomplications to date.
Conclusions: TRUS interstitial implant of the prostate under local anesthesia
is feasible. Implant time, complications, cost, and scheduling convenience,compare favorably to general or spinal anesthetic technique.
719 poster
LONG-TERM RESULTS OF HIGH-DOSE EBRT AND EBRT WITH
BRACHYTHERAPY BOOST IN TREATMENT OF PROSTATE CANCERPATIENTS.
B. Smolska-Ciszewska1 , L. Miszczyk2 , B. Białas3 , M. GawkowskaSuwinska1 , G. Plewicki1 , M. Fijałkowski3 , M. Giglok1 , K. Behrendt1 , E.
Nowicka1 , A. Zajusz1
1
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , II Radiotherapy Clinic, Gliwice, Poland
2
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , Radiotherapy Department, Gliwice,
Poland3
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , Brachytherapy Department, Gliwice,
PolandPurpose: The retrospective assessment of the effectiveness and normal tissue reactions of high-dose EBRT and EBRT with high-dose rate brachytherapy boost (HDR-BT) for prostate cancer patients.
Materials: The analysis enrolled 194 patients (group A - 96 patients who
underwent high-dose EBRT and group B - 98 patients who were treated with
EBRT with HDR-BT). The clinical characteristics of the groups were comparable: the median age was 67 years (range 49-83), the median PSA level-12,3
ng/ml (0,34-64), the Gleason score ranged from 2 to 10. Group A was treatedwith EBRT to the total dose of 74-76 Gy. The combined schedule comprised
external-beam treatment delivering 52-56 Gy (median 54 Gy) followed bytemporary HDR afterloading implant delivering 10 Gy in one fraction. Wholepelvis irradiation depended on the risk factors and oncologist decisions. The
efficacy of the treatment was evaluated by biochemical relapse-free survival(bRFS), recurrence free survival (RFS), metastases-free survival (MFS) andoverall survival (OS). Kaplan-Meier method was used to plot survival curves
and chi-square statistics to compare survival curves. Toxicity was assessed
according to EORTC/RTOG scoring criteria.
Results: All patients were followed continuously during a median of 6 years(range 0,3-7,7) Biochemical relapses according to phoenix definition (nadir
PSA +2) occurred in 49 cases: 16 in group A and 33 in group B, local recurrences in 21 patients: 4 and 17, distant metastases in 19: 8 and 11, respectively. For group A and B, the 7-year bRFS was 78% and 60% (p=0,03), RFS
83% and 71% (p=0,0004), MFS 88% and 80% (p=0,93), OS 79% and 84%(p=0,32). More grade 2 and 3 late rectal complications occurred in group A
than in group B (26% and 1% vs 9% and 0), whereas less grade 3 late urinary toxicity occurred in group A than in group B ( 2% vs 6%). No patientdeveloped grade 4 complications.
Conclusions: The analysis has shown an acceptable effectiveness and tolerance of both schedules. The long-term results of high-dose EBRT were
better. Radiation dose used in the group with a combined therapy was probably not optimal. It is advisable to use a higher dose therapy.

720 poster
OUR FIRST EXPERIENCE IN LDR PROSTATE BRACHYTHERAPY
E. Aleknavicius1 , A. Burneckis1 , A. Ivanauskas1
I NSTITUTE OF O NCOLOGY V ILNIUS U NIVERSITY, Clinic of Radiotherapy,
Vilnius, Lithuania
1

Purpose: In Vilnius University Oncology Institute we started to perform LDR(low dose rate) prostate brachytherapy technique for good and intermediaterisk prostate cancer patients in 2008-05-06. We treated 117 pts. until 201011-11. The follow-up of these patients was performed. The main purposes
were to determine: acute and late genitourinary (GU) and gastrointestinal (GI)side effects and toxicities, benefit of fosfodiesterase inhibitors to decrease GU
toxicity and PSA value dynamics.
Materials: We performed our treatment using permanent interstitial 125 I implantation delivered via real-time intra operative planning. The prescribed
dose of 125 I was 160 Gy. Treated pts. were: cT1c cT2b, Gleason score 6 andPSA value 3,13 14,4 (low and intermediate group prostate cancer patients),
median age 60 years. The prostate volume 14 56 ml. We implanted from31 to 81 permanent 125 I seeds per patient. 26% of these patients received
neoadjuvant antiandrogen hormonal treatment (1 9 moths). Treatment characteristics and follow-up data were retrospectively analyzed.
Results: Genitourinary toxicity was graded according to the the Radiation
Therapy Oncology Group/European Organization for Research and Treatment of Cancer radiation morbidity scoring system. The incidence of slight
Grade 2 acute GU (most often urination urgency, painful urination) toxicity
was and 58%, and for 70% of this patient group side effects decreased or
disappeared using fosfodiesterase inhibitors (doxazosinum, tamsulosinum),and 3 patients developed acute urinary retention 24 48 hours after implantation. The incidence of slight Grade 2 acute GI (most often mucous secretions
which disappeared without treatment) side toxicity was 15% and no higher
grade acute rectal side effects was observed. The whole follow-up incidenceof late Grade 2 GU toxicities (mostly more frequent urination) was 15%, late
Grade 3 GU toxicity was 3.3% and no higher grade late side effects was observed. Late Grade 2 GI toxicity was 11% (most often mucous secretions
which disappeared after application of steroid suppositories) and no higher
grade complications have been observed. It was hard to clearly summarise
PSA value dynamics during the period after implantation. The main ideas
which arised while investigating the PSA dynamics were that it is slow, gradual process. It seems there is no point to check PSA earlier than 3 moths
after implantation and PSA could reach nadir after 12 - 18 moths or later.
Conclusions: The PSA dynamics after permanent interstitial 125 I implantation slow, gradual process and we need longer follow up to get reliable
data. The acute and late morbidity observed in this patient group is consistent with previous reports from single institutions with significant prostate
BT experience. We have quite considerable incidence of slight acute urinaryside effects and quite low acute rectal and late gastrointestinal side effects
after permanent interstitial 125 I implantation.The acute urinary side effects
which was graded as Grade 2 was slight and well eradicated with fosfodiesterase inhibitors. We need to improve, sophisticate our toxicity grading
system because the border between Grade 1 and 2 is very unclear, especially in brachytheraphy. The PSA dynamics after permanent interstitial 125 I
implantation slow, gradual process and we need longer follow up to get reliable data Longer follow up is nessesary to get more reliable data.
721 poster
OUTCOME AFTER I-125 BRACHYTHERAPY COMBINED WITH
EXTERNAL BEAM RADIOTHERAPY FOR HIGH-RISK PROSTATECANCER
Y. Shiraishi1 , A. Yorozu1 , T. Ohashi2 , K. Toya1 , K. Yoshida1 , T. Kaneda1 , S.
Saito3 , T. Nishiyama3 , T. Hanada2 , N. Shigematsu2
1
TOKYO M EDICAL C ENTRE , N ATIONAL H OSPITAL O RGANIZATION, Department of Radiation Oncology, Tokyo, Japan
2
K EIO U NIVERSITY S CHOOL OF M EDICINE, Department of Radiation
Oncology, Tokyo, Japan
3
TOKYO M EDICAL C ENTRE , N ATIONAL H OSPITAL O RGANIZATION, Department of Urology, Tokyo, Japan
Purpose: To report the outcome after I-125 brachytherapy followed by external beam radiotherapy (EBRT) for high-risk prostate cancer.
Materials: From 2003 to 2007, a total of 195 patients with high-risk prostatecancer were treated with combined modality therapy. Patients were defined
as being high-risk if they possessed at least one of the following high-riskfeatures: Gleason score 8 to 10, PSA >20, clinical stage t2c to t3, or two or
more intermediate risk features: Gleason score 7, PSA >10 to 20, or stage
t2b. Neoadjuvant hormonal therapy was performed in 179 patients. Hormonal
therapy was discontinued after seed implantation. The prescription dose for
I-125 was set at 100 Gy. The median EBRT dose delivered was 45 Gy in 25
fractions. Patients were followed for a median of 5 years (range, 3.5 to 6.5
years). PSA failure was determined using the definition of the American Society for Therapeutic Radiology and Oncology. Toxicity was scored according
to the National Cancer Institute Common Terminology Criteria for Adverse
Events toxicity scale, version 4.

Results: The median D90 was 121 Gy, and the median V100 was 98.0%.
The median minimal dose received by 10% of the urethra was 151 Gy, andthe median rectal volume receiving a minimum of 100% of the prescribed
dose was 0.29cc. The actuarial 5-year freedom from PSA failure (FFPF) rate
was 87%. Patients included in this study because of two or more intermediaterisk features had 5-year FFPF rate of 90%, compared with 82% for patientswith one or more high-risk features (p = 0.126). Acute Grade 2 genitourinary
toxicity was seen in 17.9% and late Grade 2 in 6.2%. Acute Grade 2 gastrointestinal toxicity was seen in 5.1% and late Grade 2 in 10.3%. Late urinary
retention (Grade 3) and rectal bleeding (Grade 3) were seen in one patient
each, respectively.
Conclusions: The combined modality approach for treatment of high-risk
prostate cancer results in excellent biochemical control, and is well tolerated.
This outcome is equivalent to the report of trimodality therapy by Stock et al.
722 poster
PERMANENT BRACHYTHERAPY AS SALVAGE THERAPY FOR
LOCALLY RECURRENT PROSTATE CANCER AFTER EXTERNAL
BEAM IRRADIATION.
A. Vavassori1 , F. Cattani2 , C. Fodor1 , F. Gherardi13 , S. Comi2 , E. Rondi2 , R.
Spoto3 , R. Lazzari1 , B. A. Jereczek-Fossa13 , D. Zerini1 , V. Dell’ Acqua13 ,A. Cecconi1 , O. De Cobelli43 , B. Rocco4 , G. Musi4 , R. Orecchia13
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Radiotherapy, Milan,
Italy
2
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Medical Physics, Milan,
Italy
3
U NIVERSITY OF M ILAN, Milan, Italy
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Urology, Milan, Italy
Purpose: To estimate the incidence of acute and late toxicity and to evaluate the biochemical outcome after transperineal ultrasound-guided permanent prostate brachytherapy (PPB) for local failure after initial external beam
radiotherapy for prostate cancer.
Materials: Between August 2000 and May 2010 18 patients (pts) underwent salvage PPB using 125 I for intraprostatic recurrence after external beam
radiotherapy (EBRT).The median patient age was 68 years.Risk group distribution at initial diagnosis was as follows: low risk 4 pts (22.2%), intermediate risk 5 pts (27.8%) and high risk 9 pts (50%).All pts were treatedusing a perioperative treatment planning with dedicated hardware and software. Total re-irradiation dose was 145 Gy. Prior to PPB 12 pts were treatedwith androgen-deprivation therapy.Urinary symptoms (International Prostatic
Symptom Score, IPSS) and uroflowmetry were evaluated before treatment:
the median IPSS was 4 and the median maximum flow rate was 14 ml/sec.Radiation Therapy Oncology Group/European Organization for Research
and Treatment of Cancer criteria and Houston-Phoenix definition (PSA nadir+ 2 ng/ml) were used for toxicity and biochemical failure evaluation, respectively.
Results: The median follow-up was 28 months. One patient developed acuteurinary retention. No patient developed urinary incontinence. No rectal toxicity was observed. One patient died for prostate cancer after biochemical
failure; two pts died for other causes.Eight pts (47.1%) are alive without biochemical failure.At last follow-up the biochemical control rate using risk category at first diagnosis was 50%, 60%, and 44% in patients with low, intermediate and high risk prostate cancer, respectively.
Conclusions: Salvage PPB after irradiation is feasible with low urinary andrectal morbidity. These early results are comparable with literature.Main limitations of our study include small number of patients and short follow-up:
further experience and longer follow-up are needed to evaluate the role of
PPB in the treatment of local recurrences and to identify patients most likely
to benefit from it.
723 poster
PROSTATE BRACHYTHERAPY TREATMENT PLANNING SUPPORTED BY CONTRAST-ENHANCED ULTRASOUND TO INCREASETHE DOSE IN INTRAPROSTATIC LESIONS
B. Pieters1 , H. Wijkstra2 , M. van Herk3 , R. Kuipers2 , E. Kaljouw1 , J. de la
Rosette2 , C. Koning1
1
ACADEMIC M EDICAL C ENTER, Radiation Oncology, Amsterdam, Netherlands
2
ACADEMIC M EDICAL C ENTER, Urology, Amsterdam, Netherlands
3
ACADEMIC M EDICAL C ENTER, Biomedical Engineering, Amsterdam,
Netherlands
Purpose: To investigate the usefulness of contrast-enhanced ultrasound(CEUS) as support in treatment planning for prostate brachytherapy.
Materials: Ten consecutive patients suitable for pulsed-dose rate (PDR)
brachytherapy boost for prostate cancer were entered in the study. Patientswere first treated with external beam radiotherapy to the prostate and seminal
vesicles followed by a PDR brachytherapy boost. Twenty-four PDR pulses of
1.2 Gy were given with a 2.0 hour interval. Prior to external beam radiotherapy a CEUS was performed for identification of intraprostatic tumor lesions

S 287(ILs) with a Philips C8-4v vaginal probe. By using correlation techniques fortransversal and longitudinal planes a 3-dimensional (3-D) reconstruction of
the prostate was made. ILs were drawn on this data-set. Ultrasound (US)images for brachytherapy treatment planning were obtained from a separate
3-D volume data-set acquired with a multiplane Hitachi rectal probe. Both US
data-sets were registered to each other. The delineated ILs was available asa binary mask.Two treatment plans were generated; the first without knowledge and the second with knowledge of the location of the ILs. Dose-volume
parameters and TRAK of both plans were compared to each other.
Results: Two patients were excluded from analysis because of poor visualization of ILs and large uncertainty in image US-US fusion due to prostate
deformation. The ILs were coded as IL1 for the largest one and IL2 for thesmallest one. The mean V140% of IL1 and IL2 increased from 67.7% to95.7% and 66.0% to 92.5%, respectively when considering the plans with delineated ILs compared to without delineation. The D90 increased from 1.57 to
1.81 Gy/pulse and 1.49 to 1.76 Gy/pulse, respectively. The DVH-parameters
for the whole prostate, rectum, and urethra and TRAK were not statisticallysignificantly altered.

Conclusions: CEUS was shown to be a valuable investigation for improved,
adapted and optimized brachytherapy treatment planning for prostate cancer.
Further developments for a brachytherapy-dedicated solution are necessary
for clinical use. In this way fusion of different US data-sets is not necessary,
allowing use of one (CE)US dataset for both IL identification and treatment
planning. The advantage of treatment planning with CEUS is that uncertainties related to image fusion can be avoided. In this study, differences inprostate deformation due to probe pressure were the main cause of image
fusion problems. Also there is no need to perform image fusion with otherimaging modalities for identifying ILs.
724 poster
PROSTATE SPECIFIC ANTIGEN KINETICS FOLLOWING THE
PERMANTENT (I-125) BRACHYTHERAPY FOR PROSTATE CANCER
IN THE GREATER POLAND CANCER CENTER – PRELIMINARYRESULTS
W. Burchardt1 , B. Blasiak2 , J. Skowronek1
1
G REATER P OLAND C ANCER C ENTRE, Brachytherapy Department, Poznan,
Poland2
G REAT P OLAND C ANCER C ENTRE, Poznan, Poland
Purpose: The serum prostate-specific antigen (PSA) test is the most commonly used method to confirm response of prostate cancer after definitive
permanent brachytherapy (LDR-BT). PSA levels are expected to decrease
after LDR-BT but usually remain detectable. The aim of our work was todetermine the clinical and dosimetric factors that predict PSA bouncing andto evaluate PSA kinetics after the permanent implants brachytherapy in the
Greater Poland Cancer Center.
Materials: From December 2008 to December 2010 fifty-three patients weretreated in the Greater Poland Cancer Center with median iPSA 8.23 ng/ml(ranged 2,6 -28,8), median Gleason score 6 (ranged 2-7), median volumeof 34,2 ml (ranged 14-62), median seeds number 51 (ranged 30-82). They
were treated with I-125 brachytherapy as monotherapy to a total dose 145
Gy. ”PSA bounce" was defined as a PSA rise of >0.2 ng/ml followed by spontaneous return to prebounce level or lower, biochemical failure as ”nadir + 2
ng/ml". The PSA blood tests of 45 patients were preformed one month after
an approach and followed by three months controls. Clinical factors evaluated included: patient age, Gleason score, maximum initial pretreatment PSA
value (iPSAmax), clinical stage, prostate volume, median time to PSA nadir,median PSA nadir value and patient follow-up in months. Dosimetric factors
evaluated included the percentage of the prostate volume receiving 100%
(V100), 150% (V150) and 200% (V200) of the prescribed minimal peripheral
dose.
Results: The median follow-up was 12 (3-24, n=45) months. Urinary retention was observed in one case, in two cases bone metastases occurred andacute urinary infection. The PSA blood level decreased in forty-three cases
and the median PSA fall-down was at 91%. In two cases biochemical failure
was detected. In first case patient belonged to intermediate risk group, insecond case to a low risk group. In one cases PSA value didn’t reach upper border of normal value. Due to minimal rate of failures we didn’t observe
any differences between groups of patients with PSA bounce or biochemical
failure and clinical and dosimetric factors.

S 288B RACHYTHERAPY: P ROSTATE C ANCER

B RACHYTHERAPY: P ROSTATE C ANCER

Conclusions: Low-dose-rate brachytherapy with I-125 achieves a high rateof biochemical and clinical control in patients with low-risk disease in the shortterm evaluation. The decline of PSA following brachytherapy with low-doserate isotopes is a sign of successfully introduced technique in the Greater
Poland Cancer Center.
725 poster
SALVAGE HDR BRACHYTERAPHY FOR LOCAL RECCURANCES OFPROSTATE CANCER PRELIMINARY RESULTS
M. Gawkowska-Suwinska1 , M. Fijalkowski1 , B. Bialas1 , S. Kellas-Sleczka1 ,M. Szlag2 , J. Bystrzycka2 , A. Andrejczuk1 , A. Zajusz3 , B. SmolskaCiszewska3 , G. Plewicki3 , K. Behrendt3 , E. Nowicka3 , M. Giglok3 , K.
Olejnik4
1
C ENTRE OF O NCOLOGY - I NSTITUTE MSC G LIWICE, Department of
Brachytherapy, Gliwice, Poland
2
C ENTRE OF O NCOLOGY - I NSTITUTE MSC G LIWICE, Department of
Physics, Gliwice, Poland
3
C ENTRE OF O NCOLOGY - I NSTITUTE MSC G LIWICE, 2nd Radiotherapy
Department, Gliwice, Poland
4
C ENTRE OF O NCOLOGY - I NSTITUTE MSC G LIWICE, Department ofAnesthesia, Gliwice, Poland
Purpose: The aim of the study was to analyze early effects and toxicity of salvage high dose rate brachytherapy for local recurrences of adenocarcinoma
of prostate after external beam radiotherapy
Materials: Twenty three eligible patients were treated and analyzed fromFebruary 2008 until now. All patients had confirmed local recurrence afterradiotherapy. HDR brachytherapy was delivered using an Iridium-192 stepping source. Treatment planning was performed intra-operatively. Needle
applications were performed during spinal anesthesia. The treatment consisted of 3 fraction 10 Gy each given every 14 days. Maximal urethral doses
were constrained to be equal or less than120% of prescribed dose. Maximal
bladder and rectum doses were constrained to be equal or less than 70%
of prescribed dose.Mean PSA level before salvage brachytherapy (sBT) was
4,72 ng/ml. Thirteen patients had hormonal therapy because of recurrence,
4 patients had hormonal resistant prostate cancer.
Results: All patients completed the treatment without major complication.
The most common early complication were: macroscopic hematuria, pain inlower part of the abdomen, transient dysuria. A Foley catheter was removed
on day 2nd to 5th . No complication after spinal anesthesia were observed. After the procedure increase in IPPS score were noticed.MeanIPSS score one
month after sBT 7,9 and 12 months after sBT was 6. Bladder EORTC/RTOG
score was ranging from 0 to 2. Three pt. developed urinary retention (onerequired TURP).In two patients grade 1 toxicity for rectum was observed, 2patients complained for stools incontinence, in one of them inconsistence
persist until 9 months after treatment.Mean follow up was 12 months.Duringfollowup four patients (15%) develop metastases (3 to bone, one to lymph
nodes)The median PSA level 3, 9 and 12 PSA months after salvage HDR-BT
was respectively 0,56 ng/ml; 2,31 ng/ml;0,23 ng/mlTo better estimated theeffect of sBT on local control, PSA level was analyzed in a group of patients
without distant metastasis and with hormone sensitive tumor. The median
PSA level 3, 9 and 12 months was 0,18 ng/ml, 0,19 ng/ml and 0,16 ng/ml
respectively. Fig 1.

726 poster
SEED STRENGTH MEASUREMENTS PERFORMANCE OF AN UPGRADED SEED-LOADER SYSTEM FOR PERMANENT PROSTATEIMPLANTS
A. Bourque1 , J. Morrier1 , L. Beaulieu1
1

C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Department of Radiation Oncology, Quebec, Canada

Purpose: The FIRST seedloader (Nucletron BV, The Netherlands) is an automatic needle loading system for brachytherapy permanent prostate implants.
The system also performs seed assay while building needles for delivery. The
current clinical version does poorly, at the level of ± 3.0% average of the true
seed strength (Rivard et al. JACMP 2004). An upgraded version of the system is about to be released with several new dosimetric features avoiding
constant recalibration of the diode detectors. The transfer tube’s design waschanged to ensure constant seed-detector positioning and the seeds are now
slowly pushed for peak activity detection. Furthermore, each seed is pushed
1cm forward after detection, limiting overlap of activities from other seeds andthe need for a compensation factor. This study aims at evaluating the accuracy and reproducibility of the new system. Radiation protection analysis andvariation of the calibration factor were also assessed to establish the detector
reliability over time.
Materials: To perform accuracy and reproducibility tests, a cartridge of 45
seeds (initial Sk = 0.997 U) and 2 calibration seeds (SelectSeed from Nucletron) were used and pushed one at the time in front of the diode array.
Values of Air Kerma Strength were obtained in both our NIST calibrated WellChamber (WC) (Standard Imaging Model 70016) and from the seedloader.
Accuracy was assessed from mean deviation between WC and the seedloader, while reproducibility was obtain considering a 95% confidence interval value. Measurements (WC and seedloader) were repeated at several time
points for each seed strength range between 1.054 and 0.497 U.
Results: Measurements of the calibration seeds revealed excellent reproducibility properties with a detector accuracy of ±0.78% and ±0.46% (95%CI = 2s) for Sk = 0.616 U and 1.054 U respectively. The 45 seeds cartridge
measurements provided a low 1.00% difference of mean detected strength
between the seedloader (N = 45, s = 0.01U) and the calibrated WC (N =45, s = 0.006U). QC revealed a maximum deviation of 9.61% for one seed,with an overall standard deviation of 1.78 % confirming the detector accuracy. Radiation leakage in term of dose rate during seed detection was found
16.1µSv/h, in the worst case, this is still safe for clinical needs. Finally, thedetector calibration appears stable (under 1%) over a two months period.

Conclusions: The dosimetric performance of the new version of the Nucletron’s seedloader is much improved. The accuracy, as well as reproducibilityof the diode detector system was confirmed by cross comparison to a NIST
calibrated WC. The calibration of this new seedloader seems stable over timeand should allow accurate seed strength QC of 100% of the implanted seeds.
Radiation protection tests demonstrate the system to be safe for clinical use.
727 poster

Conclusions: Salvage HDR brachytherapy for localized prostate cancer(3 x 10 Gy every 14 days) seems to be safe and well tolerated procedure.Significant decline in PSA level is seen in patients with hormone responsive cancer, who did not developed distant metastases. Long term efficiency
and toxicity of the procedure is yet to be established.On the GEC-ESTROISIORT Europe Conference updated analysis of about 30 patients will bepresented.

SINGLE FRACTION HDR BRACHYTHERAPY AS ANTICIPATEDBOOST IN LOCALIZED PROSTATE CANCER
A. Cerrotta1 , C. Fallai2 , M. Carrara2 , M. Borroni3 , S. Villa1 , N. Bedini1 , M.
Garcia1 , A. Maucione4
1
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Department ofRadiotherapy, Milan, Italy
2
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Milan, Italy
3
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Department ofMedical Physics and Radiation Safety, Milan, Italy
4
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Department ofAnesthesia, Milan, Italy
Purpose: High dose rate (HDR) brachytherapy (BCT) has radiobiological, dosimetric, and practical advantages over external beam radiotherapy(EBRT). Actually, the radiobiology of prostate cancer seems to favor large

fractions. Accelerated hypofractionation treatments such as HDR BCT may
therefore be used to try to improve the therapeutic ratio. In December 2009 a
new HDR facility was implemented for prostate pts at the INT, Milan., and it is
our aim to report on the feasibility of the method, the dosimetric parameters
obtained, and acute toxicity during the early period after the procedure in thefirst group of pts treated.
Materials: Intermediate and high risk prostate cancer pts to be treated withradiotherapy were evaluated as candidates to combined HDR BCT + EBRT.
Pts were selected according the GEC/ESTRO-EAU recommendations on
temporary brachytherapy using stepping sources for localised prostate cancer (Kovacs G. et al. Radiother Oncol 2005; 74:137148). Patients refusing or for whom HDR BCT was considered inappropriate were addressedto EBRT alone. Pts were first submitted to epidural anesthesia, to obtainpain sedation and immobility during the procedure which is of paramountimportance for treatment accuracy and duration. As a second step the patients underwent an ultrasound scan (with a Pro Focus®B-K Medical scannerwith a 8848 transducer) to be used for an online pre-planning; on the basis of the scan the physicist indicated where and how many catheters were
to be inserted; after the catheter positioning, a second ultrasound scan was
performed to guide the actual dose delivery, and taking into account any intrafraction displacement. All HDR BCT procedures were finally performed
using a micro-Selectron (Nucletron)®. HDR BCT consisted of 1 implant, 1
fraction, 14 Gy/fraction. All the needles were removed immediately after theend of the treatment. Pts were planned to undergo EBRT (total dose 50 Gy
in 25 fractions) 2-3 weeks after completion of the HDR BCT anticipated boost
session.Dosimetric constraints for the treatment were the following: prostate,>90% of prescribed dose to >90% of the prostate volume; urethra: <115%
of prescribed dose to <0.1 cc; bladder and rectum <80% and <75% of prescribed dose, respectively, to < 2cc of the organ volume.The treatment tolerance in terms of skin, genitourinary or gastrointestinal adverse events wasmeasured according to the Common Terminology Criteria for Adverse Events(CTCAE v 4.0).
Results: From December 2009 to may 2010, 7 patients affected with histologically proved prostate adenocarcinoma were treated with HDR BCT. Meanage was 69.1 years (range 57-75 years). All pts were high risk (PSA > 20
ng/ml and /or GPS >7 and/or clinical stage T3). All procedures were completed in 4-4.5 hours.On the average 15.7 needles were needed for the implant (range 13-18 needles).The dosimetric results are reported in the following tables for the prostate and organs at risk: in all cases it was possible
to fullfill the planned dosimetric constraints.Acute tolerance immediately after
the procedure was extremely good, apart from a transient ecchymosis in theperineal area that resolved completely after 2 weeks, only one patient developed a G2 urethritis that benefitted promptly from a local anesthetic ointment(Luan®).

Conclusions: The HDR BCT schedule, as that one proposed in the present
study, consisting of 1 single session for the boost, instead of the 2 fractions
generally used, has strong practical advantages. This is a real time image
guided treatment modality as it is performed under the guidance of ultrasoundscans for both treatment preplanning and planning. This may obviate to the
problem of interfraction catheters displacement that may jeopardize a correct
dose distribution to tumor and organs at risk and may intercept intrafraction
displacement. Overall, the procedure is feasible, definitely confortable for thepatient, and without significant immediate toxicity.
728 poster
THE IMPACT OF METAL ARTIFACT CORRECTION ON POSTIMPLANT DOSE DISTRIBUTIONS IN PERMANENT SEED IMPLANTS
L. Beaulieu1 , C. Xu1 , D. Laurendeau2 , F. Verhaegen3 , S. AbbasinejadEnger1
1
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Department of Radiation Oncology, Quebec, Canada
2
U NIVERSITÉ L AVAL, Department of Radiation Oncology, Québec, Canada
3
M AASTRICHT R ADIATION T HERAPY AND O NCOLOGY (MAASTRO) CLINIC,
Maastricht, Netherlands
Purpose: Metallic objects such as prostate seeds generate artifacts in x-ray
CT images. The artifacts complicate the visualization of the prostate boundary and comprise dose calculation outcome in brachytherapy. An automatic
method for metal artifacts reduction (MAR) from brachytherapy seeds has
been used directly on raw CT data for different clinical cases. The aim of thisstudy was to quantify the impact of artifact correction on dose distributions
by calculating the absorbed dose in prostate and organs at risk using theuncorrected and the MAR corrected images.

S 289

Materials: The absorbed dose calculations were performed by using the
GEANT4 Monte Carlo code version 9.2 patch 02. Low energy electromagnetic package was used. Both sets of images were imported via DICOM RT
in Geant4, together with the contours and seed positions. The clinical CT calibration curve was applied to extract voxel densities. Prostate, rectum, bladderand inter-organ tissues were considered. A previously developed MAR algorithm from our team is used to perform seed trace detection and correction in
the sinogram space. For both corrected and uncorrected cases, the complete
seed 3D geometry (selectSeed by Isotron, Germany) was simulated such thatinter-seed attenuation is taken into account. Only the effect of the artifacts on
the absorbed dose between the two calculations remains. Ten clinical sets ofimages taken at 30 days post-implant were included in the study.
Results: The clinical target volume (CTV) D90 parameter has a mean valueof 154.8 Gy for the artifact corrected image while for the raw image the samevalue was 130 Gy. The V100, V150 and V200 values for CTV and the artifact corrected image were 93%, 76% and 60% while for the raw image themean values for the same parameters were 89%, 72% and 51%. Dose parameters for the urethra, rectum and bladder were also calculated and will bepresented.
Conclusions: We have demonstrated that metal artifacts prevent accurate
heterogeneous dose calculations in low-energy brachytherapy. Reducing themetal artifacts enables more accurate brachytherapy dose calculations. The
standard dosimetric parameters were shown to change significantly for theartifact corrected image sets.
729 poster
THE USEFULNESS OF HYBRID INTERACTIVE TECHNIQUE IN
PERMANENT PROSTATE BRACHYTHERAPY ESPECIALLY FOCUS
ON THE REDUCTION OF EXCESS SEEDS
K. Kobayashi1 , H. Yamazaki1 , K. Okihara2 , T. Iwata2 , K. Kamoi2 , T.
Tsubokura1 , T. Miki2 , T. Nishimura1
K YOTO P REFECTURAL U NIVERSITY OF M EDICINE, Department ofRadiology, Kyoto, Japan
2
K YOTO P REFECTURAL U NIVERSITY OF M EDICINE, Department of Urology,
Kyoto, Japan1

Purpose: The aim of this study is to evaluate our Hybrid interactive
brachytherapy with procedure time, dosimetry, and excess seeds. We especially focused on the reduction of excess seeds as wastes of expensive
medical materials.
Materials: Between April 2005 and April 2010, 289 consecutive patients were
underwent permanent prostate brachytherapy. Of them, we assessed 234 patients underwent Hybrid interactive brachytherapy without additional externalbeam radiotherapy. The median age of the patients was 69 year (range 46- 80). Using D’Amico classification, 51% of patients categorized as low risk,
49% were intermediate risk. To evaluate the usefulness of Hybrid interactive
method, we assessed the parameters as following; time of procedure including planning time, dosimetric factors and total excess seeds. In addition, forthe assessment of excess seeds, we calculated requiring number of seeds
according to established Nomogram and compared to our actual seed number required.
Results: Median procedure time 54 (35 - 75) minutes. prostate D90 (pD90);
170 Gy (130 - 190Gy), pV100; 97.8% (83.5 - 100), pV150; 54.6% (27.5- 82.4), Urehtral D90 (uD90); 164 Gy (130 219 Gy), uD5; 210Gy (152 259.7 Gy) No one experienced definite local recurrence or metastasis. Dosimetric results and morbidity were not inferior to the previously reported series.Around 40 50 % of patients produce excess seed five or more and 3
4% patients required further seed if we calculated by Anderson Nomogramor Mt. Sinai Lookup Table. On the contrary, the number of excess seeds
was nine in two patients (0.6%) using our Hybrid interactive brachytherapy
actually. Therefore, we can save over 10 seeds in 20 % patients.
Conclusions: Our Hybrid interactive Mick prostate brachytherapy reduced
the excess seeds, maintaining the quality of procedure and dosimetric parameters.
730 poster
VARIATION OF DOSE-VOLUME PARAMETERS IN BRACHYTHERAPY OF PROSTATE CANCER DURING MONOTHERAPY.
M. Kanikowski1 , J. Skowronek2 , A. Chichel2
1
G REATER P OLAND C ANCER C ENTRE, Brachytherapy, Poznan, Poland
2
G REAT P OLAND C ANCER C ENTRE, Poznan, Poland
Purpose: Amount of patients suffered from prostate cancer is rising all over
the world. Nowdays some of them have been treated by surgeons, the othergroup can be qualified to radical radiotherapy, usually followed by hormonal
treatment. Radiation dose to the prostate gland is possible to be given bybrachytherapy alone (HDR-BT) or in combination with external beam radiation treatment (EBRT). The aim of this work was to analyze the variationsof dose-volume parameters beetween (HDR-BT) fractions, in patients withinitially localized prostate cancer treated in monotherapy schedule.
Materials: Ten patients with prostate cancer were treated with interstitial HDR

S 290B RACHYTHERAPY: S KIN C ANCER

B RACHYTHERAPY: S KIN C ANCER

brachytherapy since June 2006 till October 2007 in Greater Poland Cancer Center. HDR-BT with a remote afterloading microSelectron unit (192Ir
source) was performed in three fractions. After brachytherapy planning (Nucletron SWIFT system has been applyed), all patients received 15 Gy of HDRBT dose per fraction. The mean value of D90 (reference dose given to 90%
of volume) was 92,03%. Hot spots parameters in target volume (V200, V150,
V120, Dmax) were found respectively: 14,97%, 39,3%, 67,53%, 1182,16%.
Mean urethral D10 (dose given to 10% of urethral volume) was estabilishedon 120,37%. Mean values of high doses parameters for urethra (Dmax, V100,
Dmean) were as follows respectively: 140,79%, 46,57%, 86,79%. Mean rectal D10 dose was estimated as 65,21%. According to parameters Dmax,
V100, Dmean (84,68%, 0,18%, 49,35%) were found as a hot spots in rectum
volume. The doses values were presented as a percent or biologic effective
dose in Gy. Comparison of dose-volume parameters was done by Friedmann
and Dunn tests.
Results: After statistical comparison we observed lower values of high target
doses (V200, V150, V120, Dmax) in the third fraction. Parameter V120 was
the only one with statistical significance in Friedmann test (p=00247). According to these changes, parameters of target doses like D90 (p=0,0608) and
Dmean (p=0,2019) were lower than previously observed (without statisticalsignificance). These corrections of dose-volume target parameters in treatment planning system caused lower values of urethral doses D10 (p=0,0608),
V100 (p=0,2019), Dmax (p=0,9048) without statistical significance. The same
parameters for another organs at risk (rectum) were higher: V100 (p=0,5258),
Dmax (p=0,1496) which can increase risk of serious complications in this localization.
Conclusions: 1. HDR brachytherapy parameters in prostate cancer treatment are not statisticaly different in most fractions. 2. High dose inside thetarget needs to be decreased during the third fraction. 3. This correction
caused higher rectum and lower urethral doses during the third fraction intreatment planning procedure. 4. Significance can be achieved by involving
more patients in Friedman’s statistical comparison.

Brachytherapy: Skin Cancer

732 poster
HIGH-DOSE-RATE (HDR) PLESIOTHERAPY WITH CUSTOM-MADE
MOULDS FOR THE TREATMENT OF SKIN TUMORS.
R. Hernanz de Lucas1 , A. Montero1 , B. Capuz2 , E. Fernández Lizarbe1 ,A. Polo1 , R. Colmenares2 , A. Hervas Moron1 , S. Sancho García1 , M. C.
Vallejo Ocaña1 , R. Morera López1 , A. Ramos Aguerri1
1
R AMON Y C AJAL H OSPITAL, Department of Radiation Oncology, Madrid,
Spain
2
R AMON Y C AJAL H OSPITAL, Department of Radiation Physics, Madrid,
Spain
Purpose: The aim of the present study is to review the efficacy and feasibility of personalized HDR plesyotherapy in the treatment of tumors other thanmelanoma arising in the skin.
Materials: From July 2005 to September 2010, 16 consecutive patients with
20 non-melanoma skin tumors were included. There were 9 females and 7
males with a median age of 84 years-old (range 59-95 years-old). There were
11 basal cell carcinomas, 6 squamous cell tumors, 2 extramammary Paget’s
Disease and 1 Merkel-cell carcinoma. Fourteen patients were treated for primary tumors whereas 2 patients were treated because of a relapsed tumor.
Sixteen lesions (80%) were located on the skin of the face, two lesions (20%)
on the skin of upper extremities and two lesions on the vulva and perianalskin. The tumor had been grossly removed in 8 cases with margins microscopically affected on the pathologist examination. In all the other cases,
only a diagnostic procedure, either FNA or punch, had been performed before treatment. All the patients were treated with custom-made moulds and
HDR plesyotherapy reaching a final dose of 44-48 Gy (median 44 Gy) in 1112 fractions (median 11 fractions) of 4 Gy over 4 weeks.
Results: With a median follow-up of 22 months (range 2-60 months) no casesof cancer death or distant metastases have been recorded. One patient suffered from local relapse 12 months after treatment, leading to a crude rate of
local control for all the tumors treated of 95%. Acute toxicity was acceptable
and cosmetic result was considered as excellent/good in 14 patients.
Conclusions: This modality of treatment offers an alternative for those patients not candidate to surgical procedures because of medical contraindications or risk of disfigurement or functional impairment.

731 poster
HDR BRACHYTHERAPY FOR SUPERFICIAL SKIN CANCERS: LESSHYPOFRACTIONATION RESULTS IN BETTER COSMESIS
R. Gauden1 , M. Pracy1 , A. M. Avery1 , I. Hodgetts1 , S. Gauden1
1
W.P. H OLMAN C LINIC, L AUNCESTON G ENERAL H OSPITAL, Launceston,Australia
Purpose: Our initial experience using recommended hypofractionated superficial brachytherapy treatment schedules resulted in less than optimal longterm cosmetic results. Accordingly, this study aimed to assess in a prospective group of patients the use of standard Leipzig (Nucletron B.V.) surface
applicators for High Dose Rate (HDR) brachytherapy, with or without surgical excision, for the treatment of small skin cancers using a more protracted
treatment schedule.
Materials: From March 2002 a total of 200 patients with 236 lesions weretreated. The median follow-up was 34 months (range 8 - 105 months). The
disease was macroscopic in 162 lesions while in 74 cases brachytherapy
was given after surgical resection because histopathology confirmed positive
microscopic margins. The study population consisted of 136 males and 64
females with a median age of 76 years (range 46 to 98 years). 121 lesions
were basal cell carcinomas, 115 were squamous cell carcinomas. 198 lesions were located on the head and neck (face excluding ear 129, ear 47,
neck 11, scalp 11), 26 on the extremities and 12 on the trunk. Treatment wasdelivered by HDR brachytherapy with standardised Leipzig surface applicators. The appropriate applicator was fitted into a thermoplastic cast, with thedimension chosen so that the lesion fell within 80% of the nominal field diameter. A total dose of 36 Gy, prescribed to the appropriate depth, generally 3
to 4mm, was given in daily 3 Gy fractions, delivered Monday to Friday. Acuteskin toxicity was evaluated weekly during irradiation using the RTOG criteria. Local response, late skin effects and cosmetic results were monitored atperiodic intervals after treatment completion. No patient was lost to follow-up.
Results: Local control for the study population was 232/236 (98%). 4 patientsrequired further surgery to treat their recurrent skin lesions. Grade 1 acuteskin toxicity was detected in 168 of the lesions treated (71%) and grade 2
in 81 (34%). All patients completed the treatment. Cosmetic results wereconsidered to be good, very good or excellent in 207 cases (88%). Late skin
hypopigmentation changes were observed in 13 cases (6%). A review ofthe dosimetry achieved with the Leipzig applicator confirms significant dose
inhomogeneity. The dose distribution can be improved with the addition of aflattening filter.
Conclusions: HDR brachytherapy with standardised surface applicators offers an effective alternative treatment technique to other radiation therapy
modalities for the treatment of small superficial skin cancers. From the clinical perspective, the technique of delivering 36 Gy over 2 weeks is well tolerated and provides a high local control rate without significant sequelae orcomplications.

733 poster
PRELIMINARY CLINICAL RESULTS USING VALENCIA APPLICATOR
AND A NEW FRACTIONATION IN NON MELANOMA SKIN TREATMENTS
A. Tormo1 , J. Pérez-Calatayud1 , S. Roldan1 , F. Lliso1 , S. Miranda1 , V.
Carmona Meseguer1 , P. Antonini1 , M. Kasper2 , Z. Ouhib2 , C. Pujol3 , A.
Ballesta4
1
H OSPITAL U NIVERSITARIO L A F E, Radiotherapy Department, Valencia,
Spain
2
LYNN C ANCER I NSTITUTE OF B OCA R ATON C OMMUNITY H OSPI, Radiation
Oncology, Delray Beach , USA
3
H OSPITAL U NIVERSITARIO L A F E, Department of Dermatology, Valencia,
Spain
4
H OSPITAL U NIVERSITARIO L A F E, Radiology Department, Valencia, Spain
Purpose: Non-melanoma skin cancers have been treated with different
modalities: surgery alone or in combination with external beam radiotherapy
or interstitial low dose rate brachytherapy. Recently, treatments have beendelivered using HDR Brachytherapy and specific applicators like the Valencia applicator. The goal was to obtain similar results in terms of cure rateand desirable cosmetic results.The purpose of this work is to evaluate theoncologic and cosmetic outcomes and the initial acute complications of cutaneous basal cell tumour treatments using the Valencia applicators in a new
fractionation regime.
Materials: We have retrospectively reviewed the results of 48 basal cell carcinomas in 33 patients, treated in our hospital between January 2008 andMarch 2010 and with a follow up between 6 and 26 months (30% of patiens
has a follow-up of more than 2 years). Most of patients were male (55%)
and 70% were older than 70.In order to provide high-rate brachytherapy doseto skin lesions, a skin applicator (Valencia applicator, Nucletron) have been
added to the micro Selectron HDR (Nucletron) unit allowing the treatment oflesions up to 4 mm deep and 3 cm in diameter.The established treatment
protocol includes the determination of the GTV-CTV area, performed by adermatologist under dermatoscopic vision, and the depth of the lesion by asoft tissue ultrasound exploration. The PTV is obtained by the addition of aradial margin between 5 and 10 mm. The treatment schedule is: 6 Gy per
fraction, 2 fractions per week in order to deliver 7 fractions (42 Gy). The doseis prescribed at 3 mm in lesions which depth is smaller than 3 mm and 4 mm
in lesions between 3 and 4 mm.
Results: Among the 38 applications, 35 were located on the face and 13
were extrafacial. In 47/48 applications the depth of the lesion was smaller
than 3 mm.At 3 months, the local control was 47/48 (97.9%) at all locations.
The maximum acute skin toxicity was grade one in all cases (RTOG).In 47/48
patients this toxicity has been resolved in 4 weeks with topical moisturizing
treatment and in one patient 8 weeks were necessary with the same treat-

ment.The cosmetic results (RTOG) have been excellent in 100% of patients.
Conclusions: In our experience, this protocol of high dose rate brachytherapy with the Valencia Applicator has turned out to be an excellent treatmentof cutaneous basal cell tumours in multiple locations regarding the short-term
local control without any severe acute complications and the cosmetic results.
Moreover, the "two fractions per week" schedule has shown to be a comfortable schedule for the patients which are mostly elderly.
734 poster
SUPERFICIAL BRACHYTHERAPY IN THE HEAD AND NECKREGION – COULD WE IMPROVE THE QUALITY OF DOSE DISTRIBUTION USING IMAGE BASED TREATMENT PLANNING.
G. Zwierzchowski12 , G. Bieleda1 , B. Blasiak1 , J. Skowronek3 , M.
Dymnicka1
1
G REATER P OLAND C ANCER C ENTRE, Medical Physics Department,
Poznan, Poland
2
P OZNAN U NIVERSITY OF M EDICAL S CIENCES, Electroradiology, Poznań,Poland3
G REATER P OLAND C ANCER C ENTRE, Brachytherapy, Poznan, Poland
Purpose: The main aim of this study was to analyse the dose distribution
parameters for image based treatment planning for skin cancer in the headand neck region, and evaluate possible benefits.
Materials: The treatment plans for three localisations were prepared using
Alderson® phantom and a set of CT images. The forehead, cheek and nose
regions were selected to analyse the dose distribution parameters for different
curvatures of skin surface. In the first step the doses for the skin surface andcontrol points 5 mm below the skin surface were recalculated. Treatment
plans for flat arrangement of the Freiburg Flap Applicator Set® were used for
curved surfaces of the head region and compared with the dose distribution
for plans with reconstructed curvature of the applicators. In the second step
the parameters of dose distribution for the simulated CTV and normal tissues
were analysed.
Results: For the forehead region, the doses for 210 points were compared,
for the cheek for 34 points, and for the nose for 60 points. The statisticallysignificant differences were observed (p<0.05, Wilcoxon Test) when the plans
prepared with flat arrangement of applicators were used on curved surfaces.
The observed doses 5 mm below skin surface were up to 22% higher than
the reference dose. For the surface of the skin, the observed doses were up
to 30% higher than for the plans with reconstructed curvature, for all three
localisations, differences were statistically significant at a=0.05 level. For theimage based plans V100 was lower by 7.9 %, 4.0% and 13.3% for forehead
cheek and nose, respectively. V150 (high dose area) was lower by 2.6%,
18.6% and 2.0%, respectively. D90 for CTV was lower by 13.0%, 8.5% and7.3% for selected regions. The doses in surrounding healthy tissues wereanalysed using D2cc and D0.1cc parameters. For the image based plans theobserved values were lower by 15.0% and 7.5% for the forehead, 9.8% and9.3% for the cheek, 10.1% and 14.0% for the nose. The maximum doses inhealthy tissues were lower by 26.3%, 18.4% and 26.5% for analysed localisations.
Conclusions: Using imaging methods for the treatment planning allows to reconstruct the curvature of applicators. The observed dose distributions weremore conservative in the target area. The doses for the surface of the skinwere lower, the high dose area was reduced. The doses in healthy tissues
were significantly reduced. When the procedure is clinically justified, using
imaging methods for reconstruction of the curvature of applicators could improve the quality of dose distribution.

S 291

ESTRO International Oncology Forum (EIOF)

S 292B REAST CANCERB REAST CANCER

Breast cancer
735 poster
A COMPARISON OF TECHNIQUES: CONVENTIONAL SIMULATORVERSES CT-VOLUMED SUPRACLAVICULAR FOSSA RADIOTHERAPY FOR ADJUVANT BREAST CANCER.
A. M. Brunt1 , S. Lupton1 , J. C. Handley2 , K. Thorley3 , L. Pearce3
1
U NIVERSITY H OSPITAL OF N ORTH S TAFFORDSHIRE, Clinical Oncology,
Stoke-on-Trent, United Kingdom
2
U NIVERSITY H OSPITAL OF N ORTH S TAFFORDSHIRE, Medical Physics,
Stoke-on-Trent, United Kingdom
3
U NIVERSITY H OSPITAL OF N ORTH S TAFFORDSHIRE, Therapeutic Radiography, Stoke-on-Trent, United Kingdom
Purpose: The aim of this paper is to provide a review of our current practice ofCT planning the supraclavicular fossa (SCF) volume and to compare it withthe previous technique of conventional simulation used in our department.
We aim to highlight the dosimetric advantages of CT planned SCF radiotherapy which UK radiotherapy centres may be in the process of considering asa development.
Materials: A cohort of the initial 50 breast cancer patients was identified retrospectively from those who had the SCF irradiated according to the new 3D CT
planning protocol. Data was collected regarding dose delivery to the PTV andcompared with what would have been given had the previous technique (a direct anterior field approach) for treatment planning been used. The previous
technique was reproduced by virtual simulation methods on the DRR reconstructed from the planning CT scan. Data collected included beam energy,
field size, PTV minimum, maximum and mean doses, depth of normalisation
and V20 lung volume.
Results: Analysis of PTV coverage using the CT volumed SCF technique
showed that 88% of plans received a mean dose which was within ICRU recommended limits compared with only 6% of plans generated by the conventional simulator technique. 76% had better coverage with 10MV rather than
6MV and 2% had a posterior opposing field. The previous technique had apredefined normalisation depth of 3cm but the new one a mean of 4.5cm.
The new technique resulted in reduction of the V20 lung dose from 5.39% to4.24% (P<0.005)
Conclusions: Dose coverage of the SCF PTV was greatly improved for plansproduced from CT volumes compared to conventional simulation.
736 poster
A DOSIMETRIC COMPARISON OF CONVENTIONAL WEDGEFIELDS VERSUS ‘FORWARD-PLANNED’ IMRT FOR TANGENTIAL
BREAST RADIOTHERAPY
H. Kerr1 , J. Pettingell2 , S. Razaq1 , K. Walsh1 , A. Eve1 , M. Robb3 , N. Mc
Andrew3 , P. Peters4 , B. Mzenda4
1
C ANCER PARTNERS UK, Elstree Cancer Centre, Elstree, United Kingdom
2
C ANCER PARTNERS UK, London, United Kingdom
3
C ANCER PARTNERS UK LTD., Portsmouth, United Kingdom
4
C ANCER PARTNERS UK LTD., Southampton, United Kingdom
Purpose: The Royal College of Radiologists recently stated(1,2) that in breast
cancer there is evidence that forward-planned tangential IMRT can be used
to reduce the toxicity of conventional wedged breast radiotherapy. They referenced the clinical trial carried out by the Royal Marsden Hospital(3) , publishedin 2007, which found a significant association of late adverse effects with thepresence of regions receiving doses ≥ 105% of the prescribed dose. Following these recommendations CancerPartnersUK treats breast patients where
the maximum dose in the conventional wedged technique exceeds 105% withforward-planned IMRT.
Materials: All intact breast and mastectomy patients were planned with boththe conventional wedged field technique and forward planned IMRT. To enable a fair comparison, the plans were normalized such that the modal dose
within the fields of both plans was the same and this was the normalization
used for the clinical treatment plan. The ’clinical maximum’ (2cc) and point
dose maximum for each plan were recorded.
Results: Considerable improvements in the size and location of the clinicalmaximum were recorded in the IMRT plans for the majority of patients. For
example, the initial results (23 patients) indicate an average clinical maximum
for the IMRT plans of 104% compared to 109% for the conventional wedged
technique. Further results will be described.
Conclusions: The use of intensity modulation in the planning of both intact
breast and mastectomy radiotherapy patients significantly reduces the maximum radiation dose for the majority of patients.

737 poster
A NEW CLINICAL APPROACH FOR RIGHT BREAST CANCER
TREATMENT: UNIQUE COMBINATION OF TOMODIRECT IMRT AND
HELICAL IMRT TECHNIQUES
A. Franzetti Pellanda1 , G. Ballerini1 , K. Schombourg1 , N. Corradini2 , R. O.
Mirimanoff3 , S. Presilla1
1
C LINICA L UGANESE M ONCUCCO, Center for Radiotherapy, Lugano,
Switzerland
2
B ETH I SRAEL, Department of Radiotherapy, New York, USA
3
C ENTRE H OSPITALIER U NIV. VAUDOIS, Department of Radiotherapy andClinical Oncology, Lausanne, Switzerland
Purpose: To apply in a single clinical approach two combined intensity modulated radiation therapy (IMRT) techniques in postoperative breast cancer
treatment: 3 fields TomoDirect and helical IMRT. We report on the feasibility,
safety and planning benefit of this new advanced technique in terms of target
coverage and organs at risk sparing.
Materials: We treated with external beam radiotherapy (EBRT) ten consecutive patients with right-sided breast cancer following breast-conserving
surgery. They received a radiation treatment of the whole breast to 50GYwith
2 Gy daily fraction followed by a boost of the tumor bed to 10 or 16 GY, 2
Gy daily. For whole breast treatment we applied 3 fixed modulated fields with
TomoDirect, two tangential fields plus an orthogonal field. Sequential boost
was performed by helical IMRT with HiArt Tomotherapy. For all patients (AP)
we used 3D treatment planning with a careful evaluation of the isodoses anddose volume histogram (DVH).
Results: Each patient received at least 95% of the dose prescription to
99% of target volume (ICRU recommandations) Concerning organs at risk,
the contralateral breast received a mean dose of 0.43Gy (0.22-0.59),themean dose for heart was 1.49Gy (0.1-5.8), the mean dose for right andleft lungs were respectively 6.85Gy (0.76-14.35) and 1.61Gy (0.16-3.86).The
right humerus received a mean dose of 0.99Gy (0.03-3.78). For one patient
the maximum dose was 112%wich was included in the PTV and for AP themean of maximum doses was 109%. The mean standard deviation for target coverage for AP was 1.4 with a maximum of 2.4. The mean value of
PTV coverage was 101.02% (99.8-103.5%). Regarding acute toxicity eightpatients presented a CTC 3 Grade 1 skin toxicity at the end of treatment andtwo patients Grade 0.
Conclusions: From our unique experience in this new clinical applicationof two combined IMRT techniques for breast cancer radiation treatment wefound a good PTV coverage and a very good sparing of the organ at risk andnormal tissue. The acute toxicity was very low without clinical impact.
738 poster
A PROSPECTIVE EVALUATION OF VERIFICATION IMAGING
FOR BREAST RADIATION THERAPY TANGENTIALLY +/- NODALTREATMENTV. Patenaude1 , C. Golling1 , E. Wai2 , D. Wells3
1
BC C ANCER AGENCY, VANCOUVER I SLAND C ENTRE, Radiation Therapy,
Victoria, Canada
2
BC C ANCER AGENCY, VANCOUVER I SLAND C ENTRE, Radiation Oncology,
Victoria, Canada
3
BC C ANCER AGENCY, VANCOUVER I SLAND C ENTRE, Radiation, Victoria,
CanadaPurpose: Radiation therapy (RT) treatment for breast cancer uses tangential fields to encompass all breast tissue while minimizing dose to lungs andheart. Standard verification protocols use tangential electronic port images(EPIs) which are compared with digitally reconstructed radiographs (DRRs).
A retrospective analysis of tangential EPIs indicated a lack of sensitivity torotational deviations which may cause clinically significant set-up errors to be
missed, particularly in the medial/lateral (ML) direction. This study evaluatedthe benefits of an anterior reference image (ANT REF), which is sensitive torotational deviations about the superior-inferior axis, to improve set-up accuracy.
Materials: The study cohort consisted of 200 patients, 100 receiving breast
irradiation and 100 receiving breast plus nodal irradiation. EPIs were taken of
all treatment fields and the ANT REF setup field. EPIs were evaluated overthree consecutive days utilizing Varian’s offline anatomy matching software.
Deviations were determined in the X-and Y-planes of the EPI and data entered into an in-house electronic worksheet that calculated corrective couchmoves in the ML, anterior/posterior (AP) and superior-inferior (SI) directions
based on two methods. Method 1 (CURRENT) used setup deviation information only from the tangential EPIs whereas method 2 (STUDY) calculated the
ML shift based on the ANT REF image and the AP shift from the tangential
image. SI shifts were calculated in the same manner for both methods. If
any setup deviation exceeded a 5mm tolerance, then corrective moves (andadditional EPIs) were taken based on the two methods
Results: The standard deviation (SD) for ML, AP and SI deviations formethod 1 was 1.7, 2.0 and 2.1mm, respectively versus 4.2, 2.7 and 2.1mm,
respectively for method 2. Method 2 detected 55 subjects which exceededtolerance versus only 10 subjects for method 1(See Figure 1). After correc-

tive moves were made using method 2, SD for ML, AP and SI deviations decreased from 6.7 to 3.7, 3.8 to 3.4 and 2.9 to 2.4mm, respectively, whereas,using method 1, SD decreased less for ML (5.9mm) and actually increased
for AP (4.7mm) post move.

Conclusions: By incorporating setup deviation information from an ANT REF
image, corrective moves for breast RT are more accurate than if deviation
information is used only from tangential images, this is especially importantas treatment techniques become more sophisticated with the use of multi-leaf
collimators and intensity modulated radiation therapy.
739 poster
ACUTE TOXICITY IN PATIENTS TREATED POSTOPERATIVELY WITH
CONCURRENT RADIOTHERAPY AND TAXANES FOR BREASTCANCER. A RETROSPECTIVE ANALYSIS
A. Huscher1 , E. simoncini2 , E. Montani3 , D. Barbieri1 , L. Bandera4 , V.
amoroso2 , B. Lazzari5 , G. Pietta5 , M. Maddalo4 , S. Pedretti4 , P. Frata16 , S.
Magrini16
1
S PEDALI C IVILI DI B RESCIA, Department of Radiation Oncology, Brescia,
Italy
2
S PEDALI C IVILI DI B RESCIA, Department of Medical Oncology, Brescia,
Italy
3
S PEDALI C IVILI DI B RESCIA, ESA Fellowship Dept Medical Oncology,
Brescia, Italy
4
S PEDALI C IVILI DI B RESCIA, University of Brescia, Brescia, Italy
5
S PEDALI C IVILI DI B RESCIA, University of Brescia, Brescia, Italy
6
U NIVERSITY OF B RESCIA, Brescia, Italy
Purpose: Breast or chest wall radiotherapy are generally not administeredconcurrent to taxanes, in order to avoid excessive toxicity. In selected cases,
however, in order to maintain an adequate timing of radiation therapy, in Our
Insitution irradiation and taxanes were delivered concurrently. Aim of thiswork is a retrospective analysis of acute toxicity in these patients. Haematological toxicity will be analysed further.
Materials: From 2004 to june 2010 160 patients meet the criteria for the analysis, that means that at least one chemotherapy cycle was delivered concurrently to irradiation. All patients were treated on chest wall or breast with
tangential fields of X Photons of 4-6 Gy on breast or chest wall. Nodal irradiation, according to internal practice was delivered only in cases with at least
4 positive axillary nodes. Supraclaviculare or axillary nodes were treated withthe same energy. 3D conformal treatment planning was applied in all cases.
In all cases heart or lung inclusion were kept below standard contraints.No
irradiation of internal mammary nodes was included in the analysis. 48%
of patients were treated on the chest wall, 52% on breasts. Primaries werestaged T1 in 46% of cases and T2 in 48%. N0 patients were less than 20%.
Grading was G3 in half of the patients. ER negative lesions were about 20%.
Half of patients were treated on right chest wall or breast. Chemotherapy
was mainly docetaxel scheduled every three weeks and generally following
antracyclines administration
Results: Patients were weekly evaluated during radiation therapy delivery.
Maximal acute skin toxicity was G3, more frequently in patients irradiated on
intact breasts, and localized to the inframammary fold (15%). The remaining
85% of patients developed a G2 or G1 reaction. Maximal grades of reactions
were recorded at a median dose of 40 Gy. No acute radiation pneumonits or
cardiac events were recorded.
Conclusions: Acute toxicity profile in this subgroup of patients seems to be
acceptable and similar to other chemo-radiotherapy regimens (e.g. CMF concurrent to chemotherapy). Concomitant administration of radiotherapy andtaxanes could reduce the interval between surgery and irradiation with potential benefits in high risk patients. Further analysis are needed to define
feasibility of this schedule in standard conditions

S 293

740 poster
ADJUVANT INTERSTITIAL HIGH DOSE RATE BRACHYTHERAPY AS
RE-IRRADIATION FOR RECURRENT BREAST CANCER-SAFETY
AND EFFICACY
B. Bahoric1 , G. Stroian1 , S. Devic1 , F. DeBlois1 , T. Muanza1 , N. Tamim1 , K.
sultanem1 , T. Vuong1
1
J EWISH G ENERAL H OSPITAL, Radiation, Montreal, Canada
Purpose: To evaluate the safety and efficacy of High Dose Rate Ir-192 (HDR)
brachytherapy for breast cancer patients, previously treated with whole breast
external beam radiotherapy (EBRT) post lumpectomy.
Materials: From May 2003 to December 2008 11 women with recurrent carcinoma of the breast received HDR brachytherapy post first or second recurrence. There were 8 invasive ductal carcinomas and 3 ductal carcinomas insitu (DCIS). Median size of recurrence was 1.2 cm (0.7-2.8 cm). The margins
at the resections were positive in 6/11 patients and close (less than 2 mm)in the rest. The median dose of brachytherapy was 30 Gy (25-31.2) in 12
fractions (10-12). The treatment was given with two to three plain implants
with 1 cm margin for PTV around the contoured cavity. Distance to the skin
was maintained at 0.5 cm. 100% dose was allowed to 1cm2 of skin.
Results: With a median follow-up of 3.3 years (1.7-5.9) 1/11 patients recurredin the irradiated field 2.6 years after brachytherapy. The same patient diedof metastatic disease 5 years following brachytherapy. Three more patientsdeveloped metastatic disease without local recurrence. One died 3.7 years
post brachytherapy of metastatic disease. There was no grade 3 toxicity, withgrade 1 telangiectasia in two patients. The cosmetic result was considered
fair to good in all patients, mostly because of previous surgeries and externalbeam radiotherapy.
Conclusions: Lumpectomy and adjuvant HDR brachytherapy is an effective
alternative to total mastectomy for recurrent carcinoma of the breast previously irradiated with EBRT. Despite close or positive margins and PTV of
only 1 cm, 10/11 patients were free of local recurrence. Distant metastasis
remains a major problem in this population of patients.
741 poster
ADJUVANT WHOLE BREAST RADIATION THERAPY DELIVEREDWITH STATIC ANGLE TOMOTHERAPY EMPLOYING TOMODIRECT:EARLY RESULTS AND TOXICITY
P. Franco1 , D. Cante1 , P. Catuzzo2 , G. Girelli1 , P. Sciacero1 , V. CasanovaBorca2 , M. Pasquino2 , F. Zenone2 , S. Tofani2 , M. R. La Porta1 , U. Ricardi3 ,F. Ozzello1
1
O SPEDALE R EGIONALE ’U. PARINI ", Radiation Oncology, Aosta, Italy
2
O SPEDALE R EGIONALE ’U. PARINI ", Medical Physics, Aosta, Italy
3
R ADIATION O NCOLOGY U NIT,U NIVERSITY OF T URIN, Turin, Italy
Purpose: Adjuvant radiation delivered to the whole breast (AWBRT) is thestandard therapeutic approach after conservative surgery for early stage
breast cancer (EBC). The most commonly employed solution consists of two
wedged tangential fields delivered with a 3D conformal field arrangement.
Recently, the TomoTherapy Hi-Art II system (TomoTherapy Inc,. Madison,
WI) has introduced an upgrade of the commercially available platform named
TomoDirectTM adding the possibility to deliver radiation at discrete angles with
Tomotherapy. The system allows for the delivery of MVCT- driven imageguided static IMRT. We herein present our preliminary clinical experience inthe clinical context of AWBRT. To our knowledge this is the first report concerning this issue.
Materials: Between May and November 2010 a total of 30 consecutive EBC
patients has been treated with TomoDirect at our Institution Hospital. Histologically proven breast adenocarcinoma pathologically staged pT1/pT2, pN0N1a were included. After planning CT acquisition and volumes contouring,
DICOM-RT images were exported to the TomoTherapy HiArt treatment planning system v4.0, where TomoDirectTM plans were generated. Patients wereprescribed 50 Gy/25 fr to the whole breast employing the TomoDirect system
and a boost dose of 10 Gy/5 fr to the surgical bed using a helical Tomotherapy
approach. The 95% percentage PTV volume should be covered at least by
95% of the prescribed dose. The PTV was restricted to <53.5 Gy at 3% volume. The constraints for the ipsilateral lung were V20Gy<10%, V10Gy<20%,
and V5Gy<42%. The constraints for the contralateral lung were V5Gy<5%,for the contralateral breast Dmax<5Gy and for the heart V25Gy<10%. All
but 4 patients received a 2-fields TomoDirect approach, while the remaining
patients a 4-fields approach.
Results: All patients completed the planned radiotherapy program with nointerruptions. At the end of ABRT, 60% of the patients had grade 0 acute toxicity, 30% experienced grade 1 acute toxicity, while 10% had grade 2 (according to RTOG). Ten patients achieved a minimal follow-up time of 6 months.
Among them, only 1 patient had grade 1 subacute toxicity (hyperpigmentation). As expected no local or systemic relapse were detected. Mean beamon time was 450 seconds for the 2 fields technique and 480 seconds for the
4 fields technique.
Conclusions: TomoDirect has demonstrated to be a feasible and efficientmean to deliver AWBRT after conserving surgery for EBC, with a robust dose
distribution, negligible toxicity, acceptable set up time and limited treatment

S 294B REAST CANCERB REAST CANCER

room occupancy time. Adjunctively, for certain anatomical sites and clinicalcontexts, where the number of beam directions is supposed not to affect planquality, TomoDirect might be an efficient mean to deliver radiation at static
angles with Tomotherapy.
742 poster
ANALYSIS OF THE RELATIONSHIP BETWEEN THE DISPLACEMENTS MEASURED BASING ON 4D-CT OF THE WHOLE BREASTTARGET AND SELECTED SKIN-MARKER AND SILVER CLIP
W. Wang1
1

S HANDONG C ANCER H OSPITAL, Radiation Oncology Department, Jinan,
China

Purpose: Based on four-dimensional computed tomography (4D-CT)to investigate the movement of the whole breast target along with respiratory cycle in the state of free breathing (FB)and to explore the relationship of thedisplacement of whole breast target and selected skin-marker, nipple and silver clip.
Materials: Thirteen breast cancer patients after breast-conserving surgery
who were recruited for whole breast intensity-modulated radiotherapy(IMRT)
gathered 4D-CT scans in FB state. The whole breast target, nipple, superior clip and skin-marker were delineated on ten respiration phases,then thedisplacements of the delineated targets in the mediolateral (X), anteroposterior(Y) and superoinferior (Z) direction were achieved, the displacement of
the whole breast and its relativity with the displacement of the clip, nipple andmarker were analyzed. The ipsilateral lung was delineated in every respiration phase and analyzed the relativity of its volume change with the displacement of whole breast.
Results: The maximum displacement of the whole breast in the state of FB
was ( 0.71±0.42 ) mm,0.76±0.40mm, and1.29±0.61mmrespectively in X , Y, and Z axes, the difference were statistically significant (F=5.755 , P=0.007).
There was no relativity between the displacement of whole breast and its volume, and there was also no relation between the displacement of the wholebreast and the volume of ipsilateral lung. There was no significant difference of mean target displacement in three-dimensional directions between
the selected two successive end-inspiration phases (EI) and three successive end-expiration phases (EE), and there was no significant difference of thevolume of whole breast between EI and EE, but the volume of ipsilateral lung
between EI and EE was significant difference (t=-10.501,P=0.000).In X andY axes, there was no relativity between the displacements of whole breast
and the displacements of nipple, skin-marker and superior clip; in Y axes,
the proportion of patients in whom the displacement of whole breast target
was relative to the displacement of nipple, skin-marker and superior clip was
8/13,7/11and 9/13,respectively, but according to the population-based analysis, the displacement of whole breast target was relative merely to the displacement of superior clipr=0.657P=0.015.
Conclusions: The whole breast target displacement in the state of FB is
maximum in Z axes; the magnitude of the volume of the breast and the volume change of ipsilateral lung is not significantly relative to the displacementof whole breast target; EI is feasible to be considered as the gating phasewhen IMRT is delivered; The clip is feasible to be used as a surrogate fortracking target movement compared with skin-marker and nipple, the clip registration is more credible and sensitive to measure and correct the displacement of the target during radiotherapy.
743 poster
BREAST CANCER IN ELDERLY WOMEN- TOLERANCE TO RADIATION THERAPY
D. Fonte1 , P. Meireles1 , A. Costa2 , G. Pinto3
1
H OSPITAL S ÃO J OÃO, Radiation Oncology, Porto, Portugal
2
H OSPITAL S ÃO J OÃO, Oncology, Porto, Portugal
3
H OSPITAL S ÃO J OÃO, Direction of Radiation Oncology Department, Porto,
Portugal
Purpose: Analysis of survival, locoregional control and toxicity in a groupof patients with breast cancer aged 65 years and older treated according to
the initial stage. The purpose of this study was to review the experience ofa single institution in breast cancer in elderly women proposed to adjuvant
radiotherapy (RT).
Materials: This is a retrospective observational study of elderly (65 years
and more) patients with breast cancer treated during the period between Jan/
2005 to May/ 2006. It reports the epidemiological analyses, clinical and therapeutic aspects of all breast cancers in elderly proposed to RT, during thisperiod.
Results: This study included 46 patients with breast cancer, stages 0-IIIC.
There was a 8,7% follow-up lost. Median age was 72 years (65-84).Eightynine percent of the patients presented with at least two comorbidities. The
majority of the tumors were invasive (93,5%) with the most common histological type being invasive ductal carcinoma (67,4%). Thirty-nine percent
of cancers were screen-detected with almost 70% being symptomatic at diagnosis. The most common stage of the tumor was IA (39,9%), followed

by stages IIA and IIB (15,2% each). Axillary nodes were positive in 36,9%.
Seventy-three percent were estrogen receptor (ER)-positive and only 6,5%
were triple negative. All except one (for cardiopulmonary contraindications)
received adjuvant RT. The majority (50%) did adjuvant RT (total dose 50-52
Gy, isocenter technique) and hormonotherapy. 67,4% were primarily submitted to conservative surgery and 19,6% to mastectomy with only one patient
requiring mastectomy after initial lumpectomy. Sixteen patients (34,8%) werealso submitted to chemotherapy (TAC, CMF or FEC).Complete response wasobtained in 91,3% of the patients. Twenty-eight percent women relapsed withmean progression disease free survival obtained by Kaplan Meyer method of
75,7 months (IC 95% : 70 81), and global survival of 119 months. Six patients died from disease progression. Distant metastases have developed in
5 (10,9%) women and 3 (6,5%) patients had developed a second primary tumor. With a mean follow-up time of 56 months (8-135 months), 78,3% of thepatients diagnosed with breast cancer are still alive. Seven patients (15,2%)
had local recurrence and local recurrence control was almost of 85%. During RT, grade I skin toxicity was reported by 36 (78,3%) patients, with only 3(6,5%) patients being classified grade 3 according to RTOG tables.

Conclusions: There is a paucity of clinical data regarding radiation therapy
in elderly patients. RT was well tolerated in all patients. According to theseresults, RT should not be omitted depending on age.

S 295

breast was 3.3% (range 1.5-6.1) in supine and 6% (range 2-12.8) in prone
position.
Conclusions: Our experience shows that prone position could decrease lungdoses but for CTV, heart and controlateral breast dosimetric data are morefavorable in the supine than in prone position. Only 3 patients received theactual treatment in the prone position due to patients compliance, their particular anatomical configuration or clear superiority of the treatment plan.
745 poster
BREAST CONSERVING THERAPY: EVALUATION OF THE TUMOR
DIAMETER AND TREATED VOLUMES
M. den Hartogh1 , E. Monninkhof1 , B. van Asselen1 , M. van den Bosch1 , M.
van Vulpen1 , P. van Diest1 , K. Gilhuijs1 , L. Van de Bunt1 , W. Mali1 , D. vanden Bongard1
1
U.M.C. U TRECHT, Utrecht, Netherlands
Purpose: In breast-conserving therapy, local recurrences are mainly foundin the original tumor bed. Therefore, both surgically tumor free resection
margins and exact localization of the postoperative tumor bed are essential.
Moreover, minimizing the excised and irradiated volumes is important, sincelarge treated volumes do significantly decrease cosmetic outcome. The purpose of this study was, to determine the exact relation between the microscopic tumor diameter (TD), the excised specimen (ES) volume and the delineated tumor bed (TB) volume in patients treated with breast conserving
therapy.
Materials: In 209 patients with pTis-2N0 breast cancer, the microscopic
tumor diameters, ES volumes and TB volumes (as delineated on theradiotherapy-planning CT scan) were retrospectively determined. Linear regression analysis was performed to study the association between these variables. Moreover, the influence of tumor characteristics (i.e. (non-) palpable
tumors, tumor location, histology) and surgical procedures were studied.
Results: Median microscopic tumor diameter was 1.2 cm (range 0.1-3.6 cm),
median ES volume was 72 cm3 (range 7-497 cm3 ) and median TB volume
was 15 cm3 (range 0.5-374 cm3 ). The explained variance for TD on the ESvolume was 7%. This association slightly increased for palpable tumors andlobular carcinomas. Re-excision caused a decrease in this association. The
explained variance for ES on the TB volume was 20%. This association decreased when the excision cavity walls were approximated by the surgeon.
Only 3% of the TB volumes could be determined by the original microscopic
tumor size.

744 poster
BREAST CANCER: COMPARATIVE STUDY OF ADJUVANT RADIOTHERAPY IN PRONE VERSUS SUPINE POSITION
P. Porcu1 , I. meaglia1 , P. tabarelli2 , M. liotta2 , G. B. Ivaldi1
1
F ONDAZIONE S ALVATORE M AUGERI, Department of Radiation Oncology,
Pavia, Italy
2
F ONDAZIONE S ALVATORE M AUGERI, Department of Radiation Physics,
Pavia, Italy
Purpose: Postoperative radiotherapy is a fundamental part of the integrated
approach to conservative treatment of breast cancer.Prone positioning has
been suggested as an alternative to conventional supine position for the patients receiving breast radiotherapy (RT). Our purpose is to compare the adequacy of target coverage, dose homogeneity and volume of organs at risks(OARs) in the treatment of the whole breast in supine and prone position.
Materials: Between 07/2010 and 12/2010, we studied 26 early stage left
breast cancer patients referred to our division to receive whole breast RT
after breast conserving surgery. Median age was 54 (range 37-76). Twocommercial immobilization devices each specific for supine and prone breast
RT were used. Contiguous 5-mm CT axial images were obtained including
the entire breast heart and lungs in both the supine and the prone positions.
Treatment plans with opposing tangential fields (6/15 MV) were performed inboth position for each patient according to ICRU criteria. Prescribed dose was
45 Gy in 20 fractions plus a concomitant electron boost of 5 Gy in 4 fractions(1fr/week). Dose volume histograms (DVH) were generated applying uniform
margins for target volumes, contralateral breast, heart and ipsilateral lung inprone vs supine position.
Results: Breast volumes were not significantly different in prone and supine
position. Median CTV in supine position was 522cc (range 134-1361) vs
558cc (range 149-1535) in prone position.In supine CTV mean dose (Dmean)
was 45.1 ± 0.5 Gy and 45.2 ±0.7 Gy in prone; mean V95% was 97.1 ± 1.7
Gy in supine and 91.9 ± 9.4 Gy in prone position. Lung doses were lower
in prone position: mean maximum lung distance (MLD) was 1.8 ± 0.6 cm
in supine position vs 0.9±0.9 cm in prone position; median V20Gy in supine
vs prone position was 6% (range 0-15.9) vs 0.2% (range 0-8.4), respectively.
However, cardiac doses increased in prone position: a 1.7 ± 0.7 Gy Dmean
was observed in supine vs 2.4 ± 1.1 Gy in prone position. Median V5Gy
heart dose in the supine and in the prone patients was 1.9% (range 0-9.5)
and 6.7% (range 0-14.8) respectively.Median Dmax of 1cc for contralateral

Conclusions: In this study, no clinically significant associations have beenfound between the microscopic tumor diameter and the excised and irradiated volumes in women with early-stage breast cancer treated withbreast-conserving therapy. Future studies should assess whether imageguided, minimally invasive operation techniques and image-guided radiotherapy might lead to a better correlation and reduction in treated volumes.

S 296B REAST CANCERB REAST CANCER

746 poster

747 poster

CARDIAC DOSES IN LEFT-SIDED BREAST CANCER PATIENTSRECEIVING TANGENTIAL FIELD RADIOTHERAPY WITH CARDIAC
SHIELDING
F. Bartlett1 , I. Locke2 , A. Kirby3
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom
2
ICR AND R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Sutton, United Kingdom

CARDIAC TOXICITY IN PATIENTS WITH BREAST CANCER UNDERGOING CONCOMITANT RADIOTHERAPY AND TRASTUZUMAB .
V. Garcia Reglero1 2 , M. Colomer1 , E. Aguirre3 , M. Mira Flores1 , C. Monfà

Purpose: The Early Breast Cancer Trialists’ Collaborative Group systematic
overview demonstrates that whole breast radiotherapy (WBRT) is associatedwith a 1% increase in non-breast-cancer-deaths at 15 years, the majority ofwhich are attributable to cardiovascular disease. Although improvements in
WBRT techniques over recent decades have led to reduced mean heart/ leftanterior-descending coronary artery (LAD) doses and falling cardiovascularmortality rates, cardiac doses from standard tangential fields remain clinicallysignificant. The current standard approach at the Royal Marsden, Sutton is
to shield cardiac tissues using multi-leaf collimation. However, this strategy
risks simultaneously shielding target tissue. We set out to determine a) mean
heart/ LAD doses resulting from our current technique, and b) the proportionof women in whom coverage of breast tissue is being compromised (ie theproportion of women in whom alternative strategies such as breath-hold or
prone positioning might be beneficial).
Materials: Sixty-seven consecutive left-sided breast cancer patients who had
undergone tangential field radiotherapy at the Royal Marsden between October 2009 and February 2010 were identified. Whole and partial breast clinicaltarget volumes (WBCTV and PBCTV), heart and LAD volumes were definedon planning CT scans according to published criteria. Mean heart/LAD doses,
maximum LAD dose (LADmax), WBCTV and PBCTV V95 were calculated
from dose-volume histograms. Data were analysed by index quadrant.
Results: Mean heart dose for all patients was 0.8Gy (range 0.2-1.7Gy),
mean LAD dose 4.5Gy (range 1.2-11.4Gy) and LADmax 33.6Gy (range 2.450.5Gy). Although there was no detectable difference in cardiac doses by index quadrant, LADmax was significantly higher for women with tumour bedsin the lower as opposed to the upper half of breast tissue (LADmax 37.6Gy(lower) vs 34.0Gy (upper) (p=0.04)). WBCTV V95 was <90% in 33% of patients, and PBCTV V95 <95% in 7% of patients. WB CTV (but not PB CTV)
coverage was more likely to be compromised in women with lower as opposed to upper half tumours (WBCTV V95 <90% in 44% vs 29% respectively).
Conclusions: Our data suggest that, despite shielding cardiac tissues with
MLC during tangential-field WBRT, clinically significant doses continue to bedelivered to heart/LAD. In addition, WBCTV coverage appears to be compromised in one third of cases. The pursuit of alternative strategies (such as
breath-hold) that can reduce cardiac doses whilst maintaining WBCTV coverage is warranted.

Zellars1
1
J OHNS H OPKINS K IMMEL C OMPREHENSIVE C ANCER C ENTER, Baltimore,USA

Binefa1 , E. Garcia Alonso1 , J. E. Baquedano Baquedano1 , Ripol1 , J. A.
Carceller1
1
H OSPITAL A RNAU D E V ILANOVA, Oncología Radioterápica, Lleida, Spain
2
I NSTITUT DE R ECERCA B IOMÈDICA DE L LEIDA (IRBLL), Lleida, Spain
3
H OSPITAL A RNAU D E V ILANOVA, Oncologia Medica, Lleida, Spain
Purpose: Trastuzumab is used as adjuvant treatment in patients with HER2 positive breast cancers. The experience with it is limited but there is invitro evidence of a radiosensitisation effect. We evaluated the incidence of
cardiac function alteration in patients with breast cancer on treatment withtrastuzumab and radiotherapy.
Materials: We analysed patients with left or right HER-2 positives breast
cancer treated with radiotherapy and trastuzumab during 2007 period. Radiotherapy was administered with two tangential fields of 6 MV photons atdose of 50 Gy in 25 fractions. Trastuzumab was given concomitantly withradiotherapy to complete one year.We evaluated the mean dose (Dm) to theheart and V30 cardiac. Cardiac function was monitored with left ventricularejection fraction (FEVI).
Results: During 2007 were treated 15 patients; 7 with right breast cancer and8 patients with left HER-2 positive breast cancer.The Dm to the heart in thegroup of right breast cancer was 0,0 Gy and in the group of left breast cancer
was 4,9 Gy.At beginning of treatment the average FEVI was 65,4% in the rightbreast cancer group and 67,6% in the left side group.Once the treatment was
finished, the FEVI value was 58,8% in the right side and 59,6% in the left
side group.The medical histories were reviewed three years after completionof radiation therapy, and none of the patients had cardiac events.
Conclusions: Despite of being a limited group of patients, we have observed
neither increase of incidence in the alteration of ejection fraction after theradiotherapy addition to trastuzumab treatment, nor the cardiac toxicity
748 poster
CATHETER DETECTION BY MEANS OF ANALYSIS OF ULTRASOUND RAW DATA
A. Poelstra1 , H. M. Overhoff1
1
U NIVERSITY OF A PPLIED S CIENCES G ELSENKIRCHEN, Gelsenkirchen,
Germany
Purpose: The planning of a high dose rate (HDR) afterloading brachytherapyof the mamma depends strongly on the position of catheters. Their location
can be determined e.g. by stereotactic mammography or even CT image
volumes. While mammography can give only restricted insight to the spatial
relations, CT is a resource consuming modality. 3-D ultrasound is a promisingalternative for image based catheter detection but suffers from poor image
contrast. It is investigated if catheters can be detected automatically in 3-D
ultrasound image volumes.
Materials: With the help of the Research Interface of a MyLab70 ultrasoundsystem (Esaote Europe B.V., Maastricht, The Netherlands), focused receive
raw data, i.e. A-lines (50 images), of patients who have underwent lumpectomy were acquired after implantation of flexible plastic tubes at the Oncologic
Department of the University Hospital Erlangen, Germany. The data were analyzed and reconstructed to images using MATLAB. Within the images, several bright, straight lines representing either catheters or tissue structures arevisible. They relate to short time samples of the raw data. It is hypothesized,that a combination of (1) the amplitude, (2) the low pass content from lower (fl)to upper (fu) cut off frequency of the Fourier spectrum of these samples and(3) the number N of spatially neighbored samples allows distinguishing between tissue und catheters. An algorithm was implemented that determines
all raw data samples with high intensity A. For these samples, the frequency
with maximal amplitude is identified. For decision whether these samples belong to a catheter, the frequency criterion and the neighborhood criterion isapplied.In a fourfold test, an optimal setting of the parameters A, fl, fu and N
was determined.
Results: The fourfold test yielded that A=183, fl = 4.75MHz, fu = 6MHz andN = 11 is a good choice to separate catheters from tissue. The figure shows
the detected catheter pixels for an exemplary chosen image.

S 297

Conclusions: The combined analysis of amplitude and frequency content ofsummed receive raw data has shown to be a promising approach to detect
catheters automatically in ultrasound images. This method can potentiallysimplify the interpretation of such typically noisy images.
749 poster
CONSERVATIVE TREATMENT OF DCIS OF THE BREAST: THE
FINAL RESULTS OF A MULTI-INSTITUTIONAL ITALIAN RETROSPECTIVE STUDY
C. Vidali1 , O. Caffo2 , C. Aristei3 , F. Bertoni4 , A. Bonetta5 , M. Guenzi6 , C.
Iotti7 , C. Leonardi8 , S. Mussari9 , S. Neri10 , N. Pietta11
1
A ZIENDA O SPEDALIERO -U NIVERSITARIA, Radioterapia, Trieste, Italy
2
O SPEDALE S ANTA C HIARA, Oncología , Trento, Italy
3
P OLICLINICO M ONTELUCE, Radioterapia, Perugia, Italy
4
P OLICLINICO DI M ODENA, Radioterapia, Modena, Italy
5
A ZIENDA O SPEDALIERA, Radioterapia, Cremona, Italy
6
I STITUTO N AZIONALE DEI T UMORI, Radioterapia, Genova, Italy
7
A ZIENDA O SPEDALIERA A RCISPEDALE S.M ARIA N UOVA, Radioterapia,
Reggio Emilia , Italy
8
E UROPEAN I NSTITUTE OF O NCOLOGY, Radioterapia, Milan, Italy
9
O SPEDALE S ANTA C HIARA, Radioterapia, Trento, Italy
10
P OLICLINICO S. O RSOLA M ALPIGHI, Radioterapia, Bologna, Italy
11
A ZIENDA O SPEDALIERA C ARLO P OMA, Radioterapia, Mantova, Italy
Purpose: To evaluate the long term clinical outcome of ductal carcinoma
in situ (DCIS) treated with conservative surgery and post-operative radiation
therapy (RT).
Materials: A collaborative multi-institutional study was conducted in Italy in 10
Radiation Oncology Departments. A consecutive series of 588 women with
DCIS histologically confirmed, treated between February 1985 and March
2000 was retrospectively evaluated.The median age was 54 years (range:
29-84); 30 patients were 40 years old or younger. All women underwent
conservative surgery followed by whole breast RT, for a median total dose of
50 Gy (range: 45-60 Gy); the tumor bed was boosted in 294 cases (50%) at
a median dose of 10 Gy (range: 8-20 Gy).
Results: After a median follow up of 136 months (range: 16-292 months),
59/588 patients (10%) experienced a local recurrence: invasive in 37 cases,
intraductal in 20 and not specified in 2. Salvage mastectomy was the treatment of choice in 46 recurrent patients; conservative surgery in 10 and it was
unknown in 2 patients. The incidence of local recurrence was significantly
higher in women younger than 40 years (31.2%) (p= 0.0009).Nine patientsdeveloped distant metastases; in 5 cases they appeared after ipsilateral invasive recurrence. Furthermore 40 patients developed a contralateral breast
cancer and 30 a second primary tumor in a different site.The 10-year actuarial overall survival (OS) was 95.5% and the the 10-year actuarial diseasespecific survival (DSS) was 99%.
Conclusions: Our results are consistent with those reported in the literature. In particular it has been defined the importance of young age (40years) as a relevant risk factor for local recurrence.This retrospective multiinstitutional italian study, which represents one of the largest series treatedconservately, confirms the long term efficacy of breast conserving surgery
with RT in women with DCIS.
750 poster
COSMETIC OUTCOME AFTER PARTIAL BREAST IRRADIATIONWITH CONCURRENT CHEMOTHERAPY IN EARLY-STAGE BREASTCANCER
L. de Souza Lawrence1 , V. Stearns1 , D. Frassica1 , F. Asrari1 , T. Tsangaris1 ,L. Myers1 , S. DiPasquale1 , J. Lange1 , L. Jacobs1 , L. Emens1 , D.
Armstrong1 , J. Fetting1 , E. Garrett-Mayer1 , N. Davidson1 , A. Wolff1 , R.

Purpose: Anthracyclines and concurrent whole-breast irradiation result inprohibitive cutaneous toxicity. We hypothesized that anthracycline-based
chemotherapy and concurrent partial breast irradiation (PBI) is safe and conducted a single-arm feasibility trial testing this hypothesis, with short-term
results as previously reported by Zellars et al (JCO 2009). We now report the long term cosmetic outcomes after concurrent anthracycline-based
chemotherapy and partial breast irradiation.
Materials: Eligible patients with T1-2, N0-1 breast cancer and ≥ 3mmlumpectomy margins received PBI (40.5Gy in 15 daily 2.7 Gy fractions) concurrently with the first two of four cycles of ddAC (60 and 600 mg/m2 of doxorubicin and cyclophosphamide, respectively, every 14 days). A modified
Harvard cosmetic scale was used to delineate the cosmetic consequences
most likely resulting from adjuvant therapy. The modified cosmetic scale useddigital images of the ipsilateral, post-surgical breast (before adjuvant therapy)
as a baseline reference. A panel of seven physicians and nurses, who were
not part of the treatment team, scored the cosmetic outcome for each patient by comparing the baseline images of the untreated breast to the images
taken at follow-up.
Results: Twenty-seven patients enrolled between November 2004 and January 2007, twenty-five of whom completed the planned PBI. One patient waslost to follow-up. Twenty-four patients had images at a median of 40 months
from the completion of therapy. Using these images, 22 (92%) had a good to
excellent cosmetic outcome. Of the remaining patients, one had a fair, andthe other a poor cosmetic outcome. The single patient with the poor cosmetic
outcome had a significant degree of fibrosis at the site of the lumpectomy
cavity, without appreciable skin changes.
Conclusions: Cosmetic outcome is influenced by both definitive (surgical)
and adjuvant therapy (radiation and chemotherapy). While we used a modified cosmetic scale to help us identify cosmetic changes which occurred only
after the immediate surgical period, it remains difficult to identify the primary
etiology of long term fibrotic changes. Nevertheless, our results indicate thatpartial breast irradiation with concurrent anthracycline therapy results in acceptable late cosmetic outcomes.(Funded by The Breast Cancer Research
Foundation)
751 poster
DO WE MUST CONSIDER MASTECTOMY AS THE STANDARDSALVAGE THERAPY FOR IPSILATERAL BREAST CANCER RECURRENCE?
J. M. Hannoun-Levi1 , T. Ihrai2 , B. Flipo3 , A. Courdi4 , F. Ettore5 , C.
Chapellier6 , A. Figl3 , I. Raoust3
1
C ANCER C ENTER A NTOINE -L ACASSAGNE . U NIVERSITY N ICE S OPHIA A NTIPOLIS, Department of Radiation Therapy, Nice, France
2
C ENTRE A NTOINE L ACASSAGNE, Department of Surgery, Nice, France
3
C ANCER C ENTER A NTOINE -L ACASSAGNE . U NIVERSITY N ICE S OPHIA A NTIPOLIS, Department of Surgery, Nice, France
4
C ENTRE A NTOINE L ACASSAGNE, Department of Radiation Therapy, Nice,
France5
C ANCER C ENTER A NTOINE -L ACASSAGNE . U NIVERSITY N ICE S OPHIA A NTIPOLIS, Department of Pathology, Nice, France
6
C ANCER C ENTER A NTOINE -L ACASSAGNE . U NIVERSITY N ICE S OPHIA A NTIPOLIS, Department of Radiology, Nice, France
Purpose: Salvage radical mastectomy is considered as the standard local
treatment for ipsilateral breast cancer recurrence (IBCR). However, in termsof Evidence Based Medicine, the proof level is not sufficient for accepting
this statement. Could a second conservative approach be proposed as analternative to the mastectomy?
Materials: From June 2005 to October 2010, 48 patients (pts) presenting withan IBCR, underwent a second conservative treatment based on a lumpectopmy followed by an interstitial high dose rate brachytherapy delivering a
total dose of 34 Gy in 10 fractions over 5 consecutive days (catheters placed
intra-operatively).
Results: With a median follow-up of 29 months, 1 pt died due to concomitantmetastatic and second local recurrence. The rate of second local control was
98%. Twenty-four pts (50%) presented breast complications scored (CTC
V3.0) as G1 for 15 pts (62.5%), G2 for 8 pts (33.4%) and G3 for 1 pt (4.2%).
A review of the literature suggests that the overall survival after IBCR is not
significantly affected by the type of local treatment. However, in case of second conservative approach, a second irradiation of the tumor bed seems toincrease the local control.
Conclusions: Currently, there is no standard local treatment for IBCR. If thepatient asks for a second conservative approach, it should be possible todiscuss an alternative to a salvage mastectomy.

S 298B REAST CANCERB REAST CANCER

752 poster
DOSIMETRIC BENEFIT OF POSTERIOR AXILLARY BOOST ON THE
AXILLARY LYMPH NODES IN BREAST CANCER
J. H. Lee1 , M. J. Chung1 , J. Y. Kim1 , G. W. Lee1 , W. C. Park2 , S. M. Chung1
1
C OLLEGE OF M EDICINE , T HE C ATHOLIC U NIVERSITY OF KOREA,
Department of Radiation Oncology, Seoul, Korea Republic of2
C OLLEGE OF M EDICINE , T HE C ATHOLIC U NIVERSITY OF KOREA,
Department of General Surgery, Seoul, Korea Republic ofPurpose: Posterior axillary boost(PAB) technique has been widely used foryears, but this technique is still unclear about the effect in the optimal dosecoverage. The purpose of this study was to evaluate the lymph node coverageof a computed tomography(CT)-based posterior axillary boost technique inthe advanced breast cancer patients.
Materials: CT simulation data of 20 consecutive patients who were treatedwith breast conserving surgery and axillary lymph node(ALN) dissection followed by radiation therapy including supraclavicular(SCV) field were selected.
Level II and III ALNs, ipsilateral lung and brachial plexus were anatomicallydelineated. Plans using three techniques were generated. Three techniques
were (1) anterior oblique supraclavicular field alone (AP); (2) anterior obliquesupraclavicular field using wedge (APW); and (3) anterior oblique supraclavicular field using posterior axillary boost(AP-PAB). Standard rules for the plans
were; (1) level II and III ALN volume percentage that receiving more than 95%
of prescribed dose was 90% or more, (2) brachial plexus should not received
more than 107% of prescribed dose, and (3) PAB field was designed to supplement to any insufficient region of the ALNs delineated on CT images. Fifty
Gy was prescribed to the ALNs.
Results: Mean treatment volume percentage receiving more than 90%(V90)
and 95%(V95) of prescribed dose were 99.5% and 95.5% in AP-PAB, compared to 85.8% and 63.0% in AP (p<0.001), and 97.6% and 88.0% for APW,
respectively(p=0.023 and p=0.001, respectively). AP-PAB showed higher
mean treatment volume percentage receiving more than 107%(V107) of prescribed dose than AP(17.9% vs. 5.7%; p<0.001), but similar with APW(14.8%; p=0.344). Homogeneity index(HI) in AP-PAB was also superior tothe other plans(p<0.001). Mean dose of ipsilateral lung increased in AP-PAB
compared to APW(46.2% vs. 46.0%; p=0.041), but ipsilateral lung volume receiving more than 20 Gy did not(23.9% vs. 23.8%; p=0.105). Mean irradiatedvolume receiving more than 40 Gy in AP-PAB was significantly less than thatin APW(573.3 cc vs. 607.8 cc, respectively; p<0.001). In terms of AP-PAB,
V95 and HI increased more significantly in patients with deep ALN(maximum
depth≥7cm) than those with shallow ALN(maximum depth<7cm)(p=0.011
and p<0.001, respectively). On the other hands, brachial plexus dose andirradiated volume decreased more in deep ALN group than in shallow ALN
group(p=0.022 and p=0.028).

Conclusions: Addition of PAB to the anterior oblique SCV field improved
dosimetric coverage of ALNs without increase of lung or brachial plexus dose.
This effect of PAB increased in deep ALN patients.
753 poster
EARLY TOXICITY RESULTS OF A FORWARD PLANNED HYPOFRACTIONATED IMRT FOR WHOLE BREAST ADJUVANT TREATMENT
A. Fodor1 , A. Bolognesi1 , P. Mangili2 , M. Pasetti1 , C. Fiorino2 , A. Chiara1 ,I. Dell’Oca1 , S. Broggi2 , A. Deli1 , N. Slim1 , G. Cattaneo2 , E. Villa1 , B.
Pappalardi1 , R. Calandrino2 , N. G. Di Muzio1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Radiotherapy,
Milan, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy

Purpose: We report the early toxicity of our forward planned IMRT(FIMRT)
approach, in low risk breast cancer patients treated with HypofractionatedWhole Breast Irradiation(HWBI).
Materials: From 02/2009-06/2010 221 patients were treated with HWBI witha schedule similar to the one of the START B trial, i.e. whole breast, 40 Gy/
15 fractions, delivered in 3 weeks. The patient median age was 61 years(28-84 yrs). The FIMRT approach was chosen to reduce skin toxicity that canbe registered with hypofractionation, maintaining a short time of treatment
planning and patient delivery.A median number of 4 segments were used(28) within a tangential two field irradiation technique. 65,8% of the patientsneeded 4 segments to obtain an homogeneous dose, with hot spots ≤ 108%
on PTV, and with 3% of the heart≤ 40 Gy D2Eq, and ≤15% of ipsilaterallung≤ 25 Gy D2Eq. For 29,7% of patients the classic 2 fields have beenenough to reach the dose costraints. The rest of the patients ( 3,5%) needed
a combination of 2-4 segments with different energies (6 MV and 18 MV).
Skin protection creams were prescribed for all patients.
Results: With a median follow-up of 7 months (1-14 months) the patients presented the following RTOG/EORTC acute skin toxicity: 86/221(38,9%) G0,
113/221(51,1%) G1, 20/221(9,1%) G2 and only 2/221(0,9%) G3. None of thepatients had to discontinue the treatment. Eleven of the patients presented adelayed (for 8-14 days after the end of RT) maximum toxicity.Considering thequadrants the toxicity was as follows: medial 212(95,9%) ≤G1 vs 9(4,1%)
G2; lateral 213(96,4%) ≤G1 vs 8(3,6%) G2; inframmamary fold 204(92,3%)≤G1vs 15(6,8%) G2 vs 2(0,9%) G3; mammary areola 210 (95%) ≤G1 vs11(5%) G2; axillary 210(95%) ≤G1 vs 11(5%) G2. Many patients experienced toxicity of only one or two of the quadrants; the most frequent in
the inframammary fold, were the 2 cases of G3 toxicity were registered.The
effect of chemotherapy on skin toxicity: 59/221 patients had a previous orconcomitant chemotherapy (51 of them with anthracyclines) and the skin toxicity was as follow: 20/59(33,9%) G0, 32/59(54,2%) G1, 6/59(10, 2 %) G2
and 1/59(1,7%) G3. 110 patients performed the six months evaluation: 96 ofthem had no toxicity (87,3%) and 14(12,7%) presented a G1 toxicity, intended
as a skin discoloration or a slight hardening of the skin.No other toxicities(tolung or heart) were registered.
Conclusions: Large studies that explored the HWBI, some of them with long
follow up (> 12 years), have found that fewer, larger doses are as effective as
conventional schedules in reducing the risk of recurrence. The FIMRT that we
adopted allowed us to get a good result of acute and subacute skin toxicity,
proving that a shorter, cheaper and more convenient three-week course ofradiation can be adopted for most patients with early stage breast cancer.
754 poster
ELECTROMAGNETIC PROPERTIES OF BREAST CANCER
I. Marinova1 , A. Chakarova2 , V. Mateev1
1
T ECHNICAL U NIVERSITY OF S OFIA, Department of Electrical Apparatus,
Sofia, Bulgaria
2
N ATIONAL H OSPITAL OF O NCOLOGY, Department of Radiotherapy, Sofia,
Bulgaria
Purpose: Determination of exact electromagnetic properties of human tissues as electric permittivity - , magnetic permeability - µ and electric conductivity σ are of paramount importance for investigations of electromagnetic
fields distributions in human body. The difference between normal and cancer
tissues properties values can be used for effective electromagnetic diagnostic and treatment methods and procedures such as impedance tomography,
radio frequency ablation, etc.
Materials: Computerized measurement system for electromagnetic field
property determination based on electric bioimpedance measurements is set
up. The measurement system is composed of precision impedance analyzer
Agilent 4294A, tissue test fixture and computer system. The measurement
frequency range is from 40Hz to 110MHz. The system is applied for measurements of surgically extracted pairs of tissue samples which contains anormal and cancer material both acquired from a same patient.
Results: Electrical conductivity σ and electrical permittivity  due to current
flow or polarization induced by an electric field in matter under investigation are measured. These properties are determined by measurement of
bioimpedance using known shape and sizes of samples. The developed approach is addressed to characterizing of the electromagnetic properties ofbreast cancer in all stages. Electric impedance amplitude and angle of breast
tissue samples are shown in Fig.1, here the normal tissue is with better conductivity in whole frequency range. Impedance frequency spectrograms are
not the same for different persons, but values of tumor and normal tissues
are always different for one patient.

S 299

were postmenopausal. Modified radical mastectomy and breast conserving
surgery rate were 55.2% and 29.3%, respectively. Adjuvant radiotherapy andadjuvant chemotherapy were prescribed in 51 (87.8%) and 56 (96.6%) patients, respectively. BRCA 1 mutation on exon 2 and 20 were positive in two
and two patients respectively and there was no statistically significance with
Her-2 status (p=0.528). BRCA 2 mutation was positive in 7 patients and allof them were Her-2 negative but it was not statistically significant (p=0.067).
There was no association with BRCA 1-2 gene mutation with stage, lymph
node involvement, histological and nuclear grade, lymphovasculary and perineural invasion (p>0.05).

Conclusions: Electric impedance measurements were performed on breast
cancer human tissue samples at different frequencies. The electromagnetic
properties of human tissues are determined by electric impedance data. Tumor and normal tissues can be distinguished on their impedance frequency
spectrums. Acknowledgement: This work was supported by the National
Science Fund of the Ministry of Education and Science of Bulgaria underContract "D002-157/2008".
755 poster
ENHANCED RAD21 COHESIN EXPRESSION CONFERS POOR
PROGNOSIS AND RESISTANCE TO CHEMOTHERAPY IN HIGHGRADE LUMINAL, BASAL AND HER2 BREAST CANCERS
M. McKay1 , H. Xu2 , M. Yan3 , Y. Yan2 , R. Ramsay2 , R. Sutherland4 , S. Fox3
1

T HE C ANBERRA H OSPITAL AND AUSTRALIAN N ATIONAL U NIVERSITY,
Radiation Oncology Department, Canberra, Australia
P ETER M AC C ALLUM C ANCER C ENTRE, Department of Research,
Melbourne, Australia
3
P ETER M AC C ALLUM C ANCER C ENTRE, Department of Pathology,
Melbourne, Australia
4
G ARVAN I NSTITUTE FOR M EDICAL R ESEARCH, Sydney, Australia
2

Purpose: RAD21 is a component of the cohesin complex, which is essential
for chromosome segregation and error-free DNA repair. We assessed its
prognostic and predictive power in a cohort of in situ and invasive breast
cancers, and its effect on chemosensitivity in vitro.
Materials: RAD21 immunohistochemistry was performed on 345 invasive
and 60 pure in-situ carcinomas. Integrated genomic and transcriptomic analyses were performed on a further 48 grade 3 invasive, cancers. Chemosensitivity was assessed in breast cancer cell lines with an engineered spectrumof Rad21 expression.
Results: RAD21 expression correlated with early relapse in all patients (HR1.74, 95% CI 1.062.86, p=0.029). This was due to the effect of grade 3 tumors (but not grade 1 or 2) in which RAD21 expression correlated with early
relapse in luminal (p=0.040), basal (p=0.018) and HER2 (p=0.039) groups.
In patients treated with chemotherapy, RAD21 expression associated withshorter overall survival (p=0.020). RAD21 mRNA expression correlated with
DNA copy number, with amplification present in 32% (7/22) of luminal, 31%(4/13) of basal and 22% (2/9) of HER2 grade 3 cancers. Variations in RAD21mRNA expression in the clinical samples were reflected in the gene expression data from 36 breast cancer cell lines. Knockdown of RAD21 in the MDAMB-231 breast cancer cell line significantly enhanced sensitivity to cyclophosphamide, 5-fluorouracil and etoposide. The findings for the former two drugs
recapitulated the clinical findings.
Conclusions: RAD21 expression confers poor prognosis and resistance tochemotherapy in high grade luminal, basal and HER2 breast cancers. RAD21
may be a novel therapeutic target.
756 poster
EVALUATION OF BRCA 1-2 GENE MUTATIONS IN PATIENTS WITH
TRIPLE NEGATIVE AND ER(-), PR(-), HER-2(+) BREAST CANCER
M. C. Uzal1 , S. Sener2 , A. Özen1 , S. Cakina2 , T. Sipahi2 , R. Cosar1 , T.
Gulyasar2 , H. Karagol3 , O. Yalcin4
1
T RAKYA U NIVERSITY M EDICAL FACULTY, Radiation Oncology, Edirne,
Turkey2
T RAKYA U NIVERSITY M EDICAL FACULTY, Biophysics, Edirne, Turkey
3
T RAKYA U NIVERSITY M EDICAL FACULTY, Medical Oncology, Edirne, Turkey
4
T RAKYA U NIVERSITY M EDICAL FACULTY, Pathology, Edirne, Turkey
Purpose: We aimed to evaluate BRCA 1-2 gene mutation in breast cancer
patients with worst prognostic factors such as triple negative and ER negative,
PR negative, Her-2 positive.
Materials: We studied 58 women who were treated with triple-negative andER negative, PR negative, Her-2 positive breast cancer. Patients data reviewed retrospectively. All blood samples were analyzed with PCR-SSCP for
BRCA 1 (185delAG exon2 and 5382insC exon20) - 2 (6174delT) gene mutation.
Results: Patients characteristics are shown in Table 1. Median age was 53(31-75). 30 (51.7%) patients were premenopausal and 28 (48.3%) patients

Conclusions: We could not find any association between BRCA 1-2 genemutation with different histopathological findings in breast cancer patientswith worst prognostic factors such as triple negative and ER negative, PR
negative, Her-2 positive.
757 poster
EVALUATION OF SICAM-1 AS A MARKER OF LUNG INJURY IN
BREAST CANCER PATIENTS UNDER RADIATION TREATMENT
M. Piperi1 , E. Kalogera2 , X. Provatopoulou2 , G. Zografos3 , E. Athanasiou1 ,A. Gounaris2
1
AG . A NARGYROI O NCOLOGICAL H OSPITAL, Radiation Oncology, Athens,
Greece2
H ELLENIC A NTICANCER I NSTITUTE, Research Center, Athens, Greece
3
H IPPOKRATIO H OSPITAL, 1st Department of Propaedeutic Surgery, Athens,
GreecePurpose: Injury to the alveolar epithelium and the vascular endothelium is a
key component of the pathogenesis of acute lung effects. Soluble intercellular adhesion molecule-1 (sICAM-1) is thought to be an important mediator ofneutrophil recruitment and trafficking into the lung, since increased expression has been demonstrated in the setting of acute lung injury. In an effort to
explore the prognostic and pathogenic significance of sICAM-1 in radiationinduced side effects, we investigated its expression in serial blood specimensof breast cancer patients undergoing radiation treatment.
Materials: In a prospective single-center study, sICAM-1 plasma levels were
measured in 38 breast cancer patients under radiation therapy and 10 healthy
controls. The mean age of the patients was 51.97 ± 11.62 years. Peripheral
venous bloodsamples were collected prior to, during (9th day), at completionof radiation treatment (38th day) and after a follow up of 2 months (90th day).
The determination of plasma sICAM-1 levels was performed in duplicates,
using Milliplex Map Immunoassay kits in a Luminex Bioanalyzer (Luminex
Corp, Texas, USA). All patients received a total dose of 50 Gy (2 Gy daily for
5 weeks), whereas 29/38 patients received an additional boost.
Results: Patients were assigned into 2 groups, according to their mediansICAM-1 plasma levels; 31/38 (81.58%) patients were assigned to group A
and 7/38 (18.42%) to group B. Group A patients exhibited low expression
levels of sICAM-1 throughout the study period (Prior: 132.84 ng/ml, 9th day:
127.53 ng/ml, 38th day: 133.65 ng/ml, 90th day: 128.97 ng/ml). Higher plasma
levels of sICAM-1 were observed in patients of group B (Prior: 310.55 ng/ml,
9th day: 242.54 ng/ml, 38th day: 234.87 ng/ml, 90th day: 256.32 ng/ml). It isnoteworthy that in group B patients, sICAM-1 expression was elevated bothS 300B REAST CANCERB REAST CANCER

before and after the radiation therapy course, however highest levels were observed prior to radiation treatment. Median sICAM-1 plasma levels in healthy
controls were 114.51 ng/ml.
Conclusions: The study was designed to explore radiation-induced side effects through the serial expression of molecules associated to acute lung injury. The results indicate that measurement of plasma sICAM-1 levels during
radiotherapy may be useful in the identification of patients at higher risk ofacute lung injury, not necessarily associated with radiation treatment.
758 poster
FIDUCIAL BASED IMAGE GUIDED RADIOTHERAPY FOR WHOLE
BREAST IRRADIATION
E. Harris1 , J. Prtiz1 , K. Latifi1 , G. Zhang1 , K. Forster1
1
H. L EE M OFFITT C ANCER C ENTER, Radiation Oncology, Tampa, Florida,
USAtheir microscopic invasion varied between 9%-17%. According to our treatment policy all this women underwent prophylactic irradiation of IM region
within 44-46Gy.
Results: Macroscopic LN invasion was diagnosed by BrS in 7 of 98(6.9%) evaluated patients. All of them were irradiated in accordance with
45Gy+10Gy strategy. In 29 (31.9%) of the remaining 91 patients lymph flow
scintigraphy revealed sentinel LN in IM region. IM LN were visualized in 15/57(26.3%) women with breast cancer localized in external quadrants and in
14/35 (40%) in central or internal regions. Only 3 (10.3%) of this 29 patients had sentinel IM LN on the both sides from sternum. In other 26 cases
IM LN were visualized on one side from midline: 12 (46.2%) on the left, 14(53.8%) on the right. Radiation dose for IM LN never exceed in this group
46Gy.
Conclusions: Two step functional imaging with 99mTc-MIBI and 99mTcnanocolloids effectively determine patients who need prophylactic IM LN irradiation and those who can benefit from IM LN boost.
760 poster

Purpose: Image guided radiation therapy (IGRT) may be beneficial to
improve set up accuracy and reduce margins around treatment volumes,
thereby improving efficacy while decreasing long term toxicity of whole breast
irradiation (WBI). In order to assess if intraparenchymal fiducials can facilitate
the use of IGRT, this study quantified fiducial motion over the entire course ofwhole breast irradiation.
Materials: On a prospective IRB-approved protocol, three or four intraparenchymal textured gold fiducial markers were placed in fifteen patients at
the periphery of the surgical bed intraoperatively. Patients were then treatedwith 3D conformal WBI over 5 to 6 weeks. Free breathing 4D CT image sets
were obtained at pre-treatment simulation and at the end of treatment. Fiducials were contoured at end-inspiration and end-expiration on all 4D CT image
sets. Respiration induced motion was assessed by comparing the positionsof the fiducials center of mass (COM) between inspiration and expiration, andlong term fiducial migration by comparing interfiducial distances between the
pre and post treatment CTs. Daily AP and LAT megavoltage (MV) images
were also acquired. Daily distortions of the breast position were estimated bymeasuring the variation of interfiducial distances on the MV images.
Results: The 4D CT image sets were acquired over a period of 55 ± 4 days
(range 49 to 60 days). The average intrafraction respiration induced fiducial
motion was 0.8mm (SD = 0.6 mm; range 0 to 2.2 mm). The average variationof respiratory motion pre- to post treatment was 0.0 mm (SD = 1.0 mm,
range -2.5 to +2.2 mm. The average fiducial migration over the entire courseof whole breast irradiation as determined from relative fiducial positions on
the repeat CT image sets was -1.2 mm (SD = 1.5 mm; range -4.2 to 1.3 mm),with fiducials moving closer to each other 71% of the time and away fromeach other 29% of the time. Daily distortions as determined by interfiducial
separations on the daily MV image sets averaged 0.7 mm (SD = 3.1 mm,
range -12 mm to 24 mm) and the distance between fiducial pairs varied by <6 mm in 95% of measurements.
Conclusions: Fiducial position was very stable during a course of wholebreast treatment, and there was minimal respiration induced motion. As expected daily variation in position caused the largest degree of variation, andthis would be reduced by aligning to fiducials daily rather than bony landmarks. Using IGRT, there is the potential to improve the accuracy of daily
set-up and to reduce margins in WBI to about 5 mm. Better tumor bed localization and reduced margin size will decrease the volume of normal tissue
treated, which may translate into improved local control by ensuring accurate coverage of the target volumes throughout the treatment course, andimprovements in cosmesis and other late normal tissue toxicities.

IMPACT OF RADIOTHERAPY (RT) ON QUALITY OF LIFE (QL) IN
ELDERLY WOMEN WITH BREAST CANCER. A PROSPECTIVE
STUDY
A. Manterola1 , G. Asin1 , M. A. Domínguez2 , J. I. Arraras3 , V. Chicata
Sutmöller2 , M. Vila2 , R. Mikel2
1
C OMPLEJO H OSPITALARIO DE N AVARRA, Radiation Oncology, Pamplona,
Spain
2
H OSPITAL DE N AVARRA, Radiation Oncology, Pamplona, Spain
3
H OSPITAL DE N AVARRA, Psycho-Oncology Unit, Pamplona, Spain
Purpose: To evaluate the impact of Radiotherapy (RT) on the Quality ofLife (QL) in elderly non-metastatic breast cancer patients (p). We also compareQL of this sample with those of a group of younger patients.
Materials: 126 p E I-III treated with local/locorregional RT with/without hormonotherapy entered in a prospective study of QL. They were invited to complete EORTC QLQ-C30 and QLQ-BR23 questionnaires and the IDDD dayli
activity scale 4 times: (1):before RT, (2):in the last week of treatment, (3):6
weeks and (4):2-3 years after finalizing treatment. All included patient havesigned the informed consent (IC).
Results: 126, 121 and 109p had completed the 3 first questionnaires, respectively. 40 p had the adequate follow up to complete the fourth. Median age
was 73.2.QL scoring were high and stable (> 70/100 points) in most areas.
There were moderate limitations (>30/100) in Global QL and sexual areas inall four measurements, and in worry about future in 3 and 4.Small limitations(20-30/100) appeared in pain and breast symptoms in 2 measurement, andin fatigue in 2 and 3.Areas of physical functioning, roll, fatigue, pain, breast
symptoms and Global QL offer worse levels in the 2 in relation to 1 and 3;
fatigue level was also worst in the 3 than in the 1 but all this differences havebeen small.Woman who had completed the 4 measurement present betterscores than in 1 except for cognitive item and corporal image. In relation
to type of surgery, scores were better with less radical surgery (conservative breast / SNB) compared to mastectomy and axillary lymphadenectomy.
Also, patients with local RT (without regional irradiation) have better physicalfunctioning.QL differences among age based samples appeared in few areas,
were small (< 15 points), and favoured younger patients.
Conclusions: Radiotherapy is well tolerated in this group of patients andthe repercussion on QL is small. Age should not be the main factor when
deciding on treatment.

759 poster

761 poster

FUNCTIONAL IMAGING AS A GUIDE FOR DIFFERENTIATEDSTRATEGY OF INTERNAL MAMMARY (IM) LYMPH NODES (LN)
IRRADIATION IN PATIENTS WITH BREAST CANCER: PRELIMINARYEVALUATION OF CLINICAL DATA.
S. Kanaev1 , S. Novikov1 , O. Zotova1 , V. Semiglazov2 , P. Krivorotko2
1
P ROF. N.N. P ETROV R ESEARCH I NSTITUTE OF O NCOLOGY, Radiotherapy
and Nuclear Medicine, St. Petersburg, Russian Federation
2
P ROF. N.N. P ETROV R ESEARCH I NSTITUTE OF O NCOLOGY, Departmentof breast cancer, St. Petersburg, Russian Federation

IMPLANT BREAST RECONSTRUCTION FOLLOWED BY RADIOTHERAPY: CAN THE TOMOTHERAPY BECOME A STANDARD OF
IRRADIATION?
C. Massabeau1 2 , N. Fournier-Bidoz1 , G. Wakil3 , A. Fourquet4 , S. Zefkili4 ,Y. Kirova4
1
I NSTITUT C URIE, Department of Medical Physics and Radiation Safety,
Paris, France
2
I NSTITUT C LAUDIUS R EGAUD, Toulouse, France
3
M ONTREAL G ENERAL H OSPITAL, Montreal, Canada
4
I NSTITUT C URIE, Paris, France

Purpose: Various nuclear medicine technologies are aimed to diagnose
macro- and microscopic LN invasion. In this study we evaluate role of nuclear medicine in differentiated radiotherapy for IM LN.
Materials: 98 consecutive patients 34-76 y.o. were included in this study.
Breast scintigraphy (BrS) with tumour seeking agent 99mTc-MIBI was used
for diagnosis of macroscopic IM LN. Acquisition in tomography regime started
15-45 min after i/v injection of 740 MBq of 99mTc-MIBI. Macroscopic LN invasion was diagnosed in the cases of local hyper accumulation of tracer in
IM LN. In these cases we irradiate IM region to 45Gy with subsequent 10Gy
boost to involved IM LN. In patients with normal BrS we determine lymph flowfrom primary tumour. LN scintigraphy in anterior projection was performed
30-60 and 240-360 min after intralesion injection of 75-150 MBq (0.5-1 ml) of
99mTc-nanocolloids. In women with visualised IM sentinel LN probability of

Purpose: To evaluate the benefits and limitations of helical tomotherapy (HT)for locoregional irradiation in patients after mastectomy and immediate implant based reconstruction.
Materials: A total of ten breast cancer patients with retropectoral implants
were randomly selected for this comparative planning study. The target volumes PTV1 (the volume between the skin and the implant plus margin) and
the PTV2 (supraclavicular, infraclavicular and internal mammary nodes, plus
margin) were given 50 Gy in 25F using either a conventional linac-basedplan (an optimised 3D field-in-field technique associated with an IMN electron beam irradiation) or intensity-modulated Tomotherapy planning. The extracted dosimetric data were compared using a two-tailed Wilcoxon matchedpairs signed-ranks test.

Results: Doses to PTV1 and PTV2 were significantly higher with HT (V95
of 98.91% and 97.91% respectively) contrarily to with the standard technique(77.46% and 72.91% respectively). Similarly, the indexes of homogeneity
were significantly greater with HT (p=0.002). The heart volume receiving 25
Gy was negligeable with both techniques. The mean heart dose was higher
with the HT technique (7.27 Gy vs. 3.53 Gy), without, however, any significant
difference for the mean left coronary artery dose. Besides, HT significantly
reduced the ipsilateral lung volume received 20 Gy or more (16.7% vs. 35%)(p=0,002) and the ipsilateral lung Dmean value (17.49 Gy with HT vs. 10.68
Gy with standard technique) (p=0,002). In HT, the dose to each OAR was
maintained below the constraint guideline but as expected, the HT techniquedelivered low doses to a greater volume of all the neighbouring organs thanthe conventional 3D technique. The mean dose (2.8 vs 0.5 Gy; p=0.002) aswell as the V5 to the contralateral breast (0.04% vs. 5.17%; p=0,002) werehigher with HT. Likewise, HT yielded a higher V5 to bilateral lungs (36.67%
vs 33.11%; p=0.010).
Conclusions: This dosimetric study is a first step to implement HT as the optimal technique for the challenging issue of locoregional irradiation following
total mastectomy and implant-based reconstruction, achieving a better target
coverage and dose homogeneity while decreasing high dose to the ipsilaterallung.
762 poster
INTERSTITIAL HDR BRACHYTHERAPY FOR PBI IN EARLY BREASTCANCER: RESULTS AFTER A MINIMUM FOLLOW-UP OF THREE
YEARS
I. Palumbo1 , A. Farneti1 , C. Raymondi2 , M. Margaritelli1 , V. Lancellotta1 , L.
Falcinelli1 , A. Cavalli3 , E. Perrucci3 , C. Aristei1
1
R ADIOTERAPIA, Dipartimento di Scienze Chirurgiche, Radiologiche eOdonstomatologiche, Università di Perugia, Perugia, Italy
2
F ISICA S ANITARIA, Azienda Ospedaliera di Perugia , Perugia, Italy
3
R ADIOTERAPIA, Azienda Ospedaliera di Perugia , Perugia, Italy
Purpose: To assess outcome after PBI with 192 Ir interstitial multicatheter
HDR brachytherapy in breast cancer patients.
Materials: From August 2003 to December 2007 85 patients (age range 4984 years; median 66 years) were treated. There were 68 infiltrating ductal, 3infiltrating tubular, 1 infiltrating papillary and 13 intraductal carcinomas. Median tumor size was 9 mm (range 2-28); ER and RPg were positive in 71
and in 51 cases respectively, Ki-67 was over-expressed (>25%) in 11, p53
was over-expressed (>20%) in 7, cERB-B2 was positive in 4 . Eight patients
received adjuvant chemotherapy (CMF 1-8 for 6 cycles in 4, CMF 1-8 for 6
cycles followed by trastuzumab in 1, FEC for 6 cycles in 1, FEC for 4 cycles
plus paclitaxel for 4 cycles in 1 and epirubicine for 14 weekly administrationsin 1); hormone therapy was prescribed in 66 cases (tamoxifen in 24 and anastrozole in 42). Brachytherapy treatment schedule was 4 Gy twice a day for 4days, up to a total dose of 32 Gy, with an interval between fractions of at least
6 hours. Toxicity was classified using EORTC/RTOG criteria, and teleangiectasia using the Turesson and Notter scale, modified by Van Limbergen.
Results: Median follow-up was 58 months (range 5-85). Incidence of perioperative and acute toxicity was very low: haematoma was observed in 7 casesand cutaneous erythema in 8. Late toxicity was: breast pain in 1 patient, G3
cutaneous toxicity in 1, G1 subcutaneous toxicity in 7, teleangiectasia in 14(13 G1,1 G2), fat necrosis in 10 . Two local relapses developed. One occurred 4 years after PBI (pT2N2aM0; CDIG2 ER 40%, PgR 40%, Ki-67 10%,cERBB2 1+; localized in a different quadrant) and was treated with mastectomy and axillary dissection followed by EBRT to chest wall and supraclavicular fossa. The second was diagnosed 19 months after PBI (pT1bN2aM0,
CDIG2 ER 80%, PgR 0%, Ki-67 28%, cERBB2 negative; localized in a different quadrant) and was treated with BCS and axillary dissection followed by
adjuvant chemotherapy (docetaxel and cyclophosphamide for 6 cycles) and
EBRT to residual breast and supraclavicular fossa with a boost to the tumoral
bed. One regional relapse occurred 7 months after BRT (supraclavicular andaxillary nodes) and was treated with EBRT. At 34 months after BRT the same
patient developed haepatic and bone metastasis. Only 1 died of metastatic
disease, 1 of multiple myeloma, 1 of haepatic adenocarcinoma, 1 of lungadenocarcinoma, 1 of cerebral neoplasm, 1 of gastric lymphoma and 1 ofgallbladder cancer.
Conclusions: Our data show that PBI with 192 Ir interstitial multicatheter HDR
brachytherapy is associated with low perioperative and acute and late toxicity. The relapse rate was similar to the best that has been reported elsewhere. No higher toxicities were observed even in patients who had received
chemotherapy.
763 poster
INTRAOBSERVER AGREEMENT AMONG RADIATION ONCOLOGISTS AND TECHNOLOGISTS IN BREAST EPI VERIFICATION
B. A. Jereczek-Fossa12 , L. Santoro3 , S. P. Colangione12 , F. Cattani4 , L.
Morselli2 , D. Rozza1 , A. Leppa1 , M. C. Leonardi1 , M. Sarra Fiore1 , R.

S 301

Orecchia12
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Radiation Oncology,
Milan, Italy
2
U NIVERSITY OF M ILAN, Milan, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Epidemiology andBiostatistics, Milan, Italy
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Medical Physics,
Milan, Italy
Purpose: To check the inter-observer agreement among radiation oncologists and technologists using EPI protocol for breast cancer RT.
Materials: The inclusion criteria for the study were as follows: non-metastatic
breast cancer, indication for postoperative (breast conserving surgery or mastectomy) irradiation including tangential fields only, availability of routine setup verification data using on-line EPI institutional protocol (performed on-line
by a radiation oncologist). For the purpose of this study, these on-line firstfraction EPI data were employed as a reference data set. All first-fraction EPI
images were reviewed independently off-line by 2 blinded radiation technologists.
Results: The first-fraction EPI data of 40 consecutive pts were analyzed. A
total of 80 images were analyzed (medio-lateral and latero-medial EPI image
for each of 40 pts) and 240 measurements were reported for each observer (3measurements for each EPI image), so a total 720 measurements were analyzed. Mean misalignment between EPI and reference digitally reconstructedradiograph (DRR) was < 2 mm (standard deviation < 3 mm). The difference
in measurements between observers was < 2 mm in 92.5% of cases. Highobserver agreement was found (table 1).

Conclusions: Our study showed significant agreement between radiation
oncologists and technologists in the manual EPI registration of breast cancer
tangential field radiotherapy. These findings are useful in quality assurance
and in the optimization of workload in the radiotherapy departments.
764 poster
INTRAOPERATIVE RADIOTHERAPY FOR MANAGEMENT OF
DUCTAL CARCINOMA IN SITU: A PILOT STUDY
D. Holmes1 , S. Villegas-Mendez1 , R. Afshin2 , O. Streeter3
1
USC N ORRIS C OMPREHENSIVE C ANCER C ENTER AND H OSPITAL, Surgical
Oncology, Los Angeles, USA
2
USC N ORRIS C OMPREHENSIVE C ANCER C ENTER AND H OSPITAL,
Radiation Oncology, Los Angeles, USA
3
H OWARD U NIVERSITY, Radiation Oncology, Washington, DC, USA
Purpose: Intraoperative radiotherapy (IORT) has emerged as an efficacious,
convenient, and low morbidity approach for administering accelerated partial
breast irradiation at the time of lumpectomy for invasive breast cancer. However, the use of IORT in the management of ductal carcinoma in situ (DCIS)
is limited by the inherent challenges of evaluating the extent of disease andensuring adequate tumor resection in patients with pure DCIS. As a result,in the absence of pre-treatment surgical pathology results, patients with pure
DCIS are commonly excluded from protocols evaluating the use of IORT in
the management of DCIS.
Materials: IORT was administered immediately following lumpectomy or reexcision in women with pure DCIS under an IRB-approved protocol. Prior to
IORT, all patients were evaluated preoperatively with digital diagnostic mammography and bilateral breast contrast enhanced MRI (1.5 Tesla) to evaluate
the extent of residual disease, and patients with imaging evidence of DCIS
> 4cm were excluded from IORT. All eligible patients underwent 2-wire localizations to bracket residual imaging abnormalities or biopsy site markers
Following specimen radiography, IORT was administered to the tumor bed
using the Intrabeam Photon Radiosurgery System (Carl Zeiss-Meditec, Inc.,
Oberkochen, Germany), with a prescribed dose of 20 Gy to the surgical margins. Diagnostic imaging studies, core needle biopsy, and surgical pathology
results were evaluated to identify factors associated with successful breast
conserving surgery with IORT.

S 302B REAST CANCERB REAST CANCER
Results: The 5 - years and 10 - years overall survival (OS) was 44% and10%. The 5 years and 10-years Disease free survival(DFS) was 36% and
11% .Local and distant metastasis were seen in 8% and 30% of the patients
respectively. In our series, univariate analysis for OS showed statistical significance for duration of symptoms (p=.0462) and type of cancer(p=.0000)
while poorly differentiated tumor (p=.1125),pathological stage (p.1266) andaxillary lymph node involvement (p=.34) although demonstrated no statisticalsignificance yet clinically we noted their significance.
Conclusions: This study shows MBC presents late and out look of majorityof patients treated with surgery remains poor. The OS and DFS are clearlyless than female breast cancer locally and internationally. We suggest education, facilities for early detection and adequate treatments are necessary
for improving outcomes.
766 poster

Results: Sixteen (16) patients with DCIS underwent lumpectomy (n=13) or
re-excision (n=3) followed by IORT. Breast conserving surgery (BCS) was
successfully performed in 94% (15/16) of patients receiving IORT. For patients who received IORT at the initial lumpectomy, 92% (12/13) had successful breast conserving surgery (BCS). Two of the twelve successful lumpectomy patients required additional therapy to re-excise margins <1mm. The
one unsuccessful patient underwent repeat re-excision and subsequent mastectomy for transected margins. Among the 3 patients who first received
IORT during a re-excision for positive or close margins, 100% (3/3) successfully underwent BCS and required no additional surgical or radiation therapies. Among patients receiving IORT at the time of lumpectomy, the mean
maximal diameter of the DCIS was 18.9mm (range: 3-30mm) by pathology
and 14.4mm (range: 6-40mm) on digital mammography. The lesion could
only be detected by MRI in 46% (6/13) of patients and by ultrasound in 39%(5/13) of patients for mean maximal diameters of 16.6mm (range 8-38mm)
and 15.6mm (range 7-26mm) respectively.
Conclusions: IORT is a feasible treatment option for breast conserving
surgery in women with DCIS. Although 3/16 patients required additional therapy due to inadequate surgical margins, 77% of patients receiving IORT at
the time of initial lumpectomy required no additional surgery or radiotherapy.
Although the best outcomes were obtained in patients who received IORT at
a second operation, most patients who received IORT at the time of the initial
lumpectomy were spared a second operation or the need for post-operative
radiotherapy. The 23% re-excision rate for DCIS is well within the accepted
standard for DCIS treated with lumpectomy, and only one of 13 patients who
received IORT at the initial lumpectomy failed to meet the NSABP standard ofclear margin resection-non-transection. In this study, mammography was thebest predictor of histological lesion size because lesions could be identifiedin each patient. Perhaps as a result of the small lesion size, non-visibility of
the lesion(s), and the use of core needle biopsies, MRI and ultrasound had
limited value for predicting lesion size in women with pure DCIS.

MAMMOGRAPHIC FINDINGS AFTER INTRAOPERATIVE RADIOTHERAPY OF THE BREAST
D. Holmes1 , R. Rivera1 , P. Sheth2 , S. Villegas-Mendez1 , V. Smith-Bronson3
1
USC N ORRIS C OMPREHENSIVE C ANCER C ENTER AND H OSPITAL, Surgical
Oncology, Los Angeles, USA
2
USC N ORRIS C OMPREHENSIVE C ANCER C ENTER AND H OSPITAL,
Radialogy, Los Angeles, USA
3
USC N ORRIS C OMPREHENSIVE C ANCER C ENTER AND H OSPITAL,
Student, Los Angeles, USA
Purpose: Intraoperative Radiotherapy (IORT) is a form of accelerated partial breast radiation that has been shown to be equivalent to conventional
whole breast external beam radiotherapy (EBRT) in terms of local cancer
control. Our goal was to identify, quantify, and compare the pre and post surgical mammographic findings of patients who received IORT and EBRT in aprospective, randomized controlled clinical trial.
Materials: This is a descriptive analysis of mammographic findings performed by an independent, blinded breast radiologist at a Comprehensive
Cancer Center. It included patients with early stage invasive breast cancer undergoing breast conserving therapy between July 2005 and December
2009. Treatment groups were compared with regard the 1, 2 and 4 year incidence of 6 post-operative mammographic findings: architectural distortion,skin thickening, skin retraction, calcifications, fat necrosis, and mass density.
Results: Blinded review of 93 sets of mammograms of 15 IORT and 16 EBRT
patients demonstrated no statistically significant difference on univariate analysis in the incidence of each outcome measure at years 1, 2, and 4.

765 poster
MALE BREAST CANCER IN PAKISTAN: A RETROSPECTIVEANALYSIS
I. Haider1 , S. M. A. Bokhari2
1
S HAUKAT K HANUM C ANCER H OSPITAL, Departement of Radiation
Oncology, division Radiobiology, Lahore, Pakistan
2
S HAUKAT K HANUM C ANCER H OSPITAL, Department of Surgery, Lahore,
PakistanPurpose: Male Breast Cancer (MBC) is very rare and accounts for less than
one percent of all cancers in men. We report on clinicopathological characteristics and survival in non metastatic MBC at presentation treated in our
institution.
Materials: The hospital cancer registry identified 52 patients with nonmetastatic MBC treated between 1994 and 2009. Demographics, clinical,
pathological and treatment variables were extracted from the medical records.
The median age of presentation was 57 years (Range 20 to 80years). The
most common presentation was breast lump in 98% and lump with nipplechanges 2% .Family history of breast cancer was present in 8% of cases.
Infiltrative ductal carcinoma was found in 86%, papillary carcinoma 6%, insitu ductal carcinoma 2%, invasive lobular 2%, liposarcoma 2% and spindlecell carcinoma 2%. Histological grades I,II and III were 10%,46% and 44%
respectively. Estrogen receptor and Progesterone receptor were positive in
75% and 83% respectively. Most common pathological tumor size (pT) was
pT2(56%) while pT4 was 12%. Regional lymph node involvement was diagnosed in 56% of patients. The incidence of pathological stages 0, I, II, III inpatients were 6%, 2%, 65%, and 27% respectively. MRM was a standard
procedure in 86% of cases and mastectomy alone in 14%. Sixty percent
received adjuvant chemotherapy and only 4% cases got Neo-adjuvant. Radiation therapy done in 65 % of cases and 77% cases received hormonal
therapy .

Conclusions: Mammographic findings following single fraction intraoperative
accelerated partial breast radiotherapy were indistinguishable from the mammographic findings of patients undergoing conventional breast radiotherapy.
Compared to EBRT, there was no indication that IORT impaired mammographic surveillance for breast cancer recurrence.
767 poster
PARTIAL BREAST IRRADIATION WITH CONCURRENT DOSE
DENSE DOXORUBICIN & CYCLOPHOSPHAMIDE: LATE TOXICITY &RECURRENCE
R. Zellars1 , D. Frassica1 , V. Stearns2 , F. Asrari1 , J. Fetting2 , D. Armstrong2 ,L. Myers1 , T. Tsangaris3 , J. Lange3 , L. Emens2 , E. Garrett-Mayers4 , N.
Davidson5 , A. Wolff2
1
J OHNS H OPKINS K IMMEL C OMPREHENSIVE C ANCER C ENTER, Radiation
Oncology and Molecular Radiation Sciences, Baltimore, USA
2
J OHNS H OPKINS K IMMEL C OMPREHENSIVE C ANCER C ENTER, Medical
Oncology, Baltimore, USA
3
J OHNS H OPKINS K IMMEL C OMPREHENSIVE C ANCER C ENTER, Surgery,
Baltimore, USA
4
U NIVERSITY OF S OUTH C AROLINA, Biostatistics, Columbia, USA
5
U NIVERSITY OF P ITTSBURGH, Medical Oncology, Pittsburg, USA
Purpose: Anthracyclines and concurrent whole breast radiation result in prohibitive cutaneous toxicity (40% grade 4 radiation dermatitis-Fiets et al., Eur J

Cancer, 2003). However, with the advent of partial breast irradiation (PBI), we
hypothesized that anthracycline-based chemotherapy and concurrent breast
irradiation may now be tolerable. Potential benefits of concurrent chemoradiation include: shorter duration of overall therapy, greater efficacy from thedelivery of therapy closer to surgery, and better local control via the radiation sensitizing effects of chemotherapy. This is of particular interest with recent reports of increased local regional failure in patients with triple negative(ER/PR/HER2-) breast cancer. Thus we conducted a single arm feasibility
trial of PBI with concurrent chemotherapy. We have previously reported that
acute toxicity is minimal. We now present the late skin and subcutaneous
tissue toxicity and recurrence rates.
Materials: Women with T1-2, N0-1 breast cancer with ≥3 mm lumpectomy
margins received PBI (40.5 Gy in 15 daily 2.7 Gy fractions) concurrently withthe first 2 of 4 cycles of ddAC (60 and 600 mg/m2 respectively, every 14 days
with colony-stimulating factor support). The primary endpoints of skin/soft tissue toxicities were graded by the treating physician and nurse according to
the Common Terminology Criteria for Adverse Events manual (version 3.0).
Additional, systemic therapy after ddAC was given at the physician’s discretion. Cosmetic outcomes will be reported separately.
Results: Twenty-seven patients enrolled between 11/04 and 1/07. Two patients did not receive protocol therapy (one withdrew consent and anotherwas found to have metastatic disease on work up). One patient withdrew
consent after completing therapy. Median tumor size was 1.8 cm (range 0.4-3.0cm), 62% were pN0, 46% were ER positive, 42% were triple negative(ER/PR/Her2-) and 50% received Taxol after ddAC. With a median f/u of 54
months (range 35-74 months), the observed rate of ≥ grade 2 late skin, andsubcutaneous tissue toxicity was 0% and 4% respectively. Although powered
for a feasibility trial, there have been no local/regional or distant recurrences.
Conclusions: These results suggest that PBI with concurrent ddAC is tolerable. No patient had grade 3, or 4 late skin or subcutaneous tissue toxicity(one sided 95% CI, 0% to 12%). With nearly 5 years of f/u there have been norecurrences. Based on these results we have initiated a second trial of PBI
and concurrent chemotherapy with various systemic regimens. The results ofthis study deserve validation in a larger trial.(Funded by The Breast Cancer
Research Foundation)
768 poster
POSTMASTECTOMY
RADIOTHERAPY
AFTER
EXPANDER/IMPLANT
BREAST
RECONSTRUCTION:ANALYSIS
OF 101 CONSECUTIVE CASES
E. Perrucci1 , L. Falcinelli1 , V. Bini2 , M. Scricciolo1 , I. Palumbo1 , A. Farneti1 ,R. Crisci1 , R. P. Petitto1 , G. Verzini1 , C. Aristei1
1
I STITUTO DI R ADIOTERAPIA, Dipartimento di Scienze Chirurgiche,
Radiologiche e Odonstomatologiche, Università di Perugia, Perugia, Italy
2
I STITUTO DI M EDICINA I NTERNA, Dipartimento Medicina Interna Perugia,
Perugia, Italy
Purpose: . After mastectomy the breast is reconstructed with autologous
tissues or tissue expander/implant. A few studies with small numbers of patients and short follow-ups reported a high incidence of complications andpoor cosmetic outcomes after radiotherapy (RT), particularly in patients who
had undergone expander/implant reconstruction. Risk factors were identified as the smoking habit, diabetes, obesity, vascular disease and hypertension. The present study retrospectively analysed outcomes after mastectomy,
breast reconstruction with tissue expander, with or without definitive implant,
and RT.
Materials: From July 1997 to July 2009, data were analysed from 101 breast
cancer patients (mean age 50 years, range 30-79; 32 smokers; 26 obese;
8 with diabetes; 2 with vascular disease) . Disease staging: 19 T1, 43 T2,
16 T3, 13 T4, and 9 chest wall relapses with skin infiltration in 18 cases andmuscle infiltration in 5. Histology: ductal carcinoma in 88, lobular carcinoma
in 9 and other histologies in 4. Grading: G1 in 2 , G2 in 44 and G3 in 39.
Positive resection margins in 6 cases and lymph-vascular invasion in 4. Axillary nodes were positive in 92 and negative in 9. Treatment: 93 patients
received adjuvant chemotherapy (82 with antracyclin-based schemes) and
79 hormone therapy. RT was delivered to the chest wall in all patients and to
the draining nodes in 76. 4-6 MV photons were used; single dose was 1.8-2.0
Gy and total dose 50-50.4 Gy. In 2 cases a boost was administered to thethoracic wall. The X2 tested the association between categorical variables
and Cohen’s k the agreement on aesthtetic valuation. The Kaplan-Meier estimated cancer-specific survival rates and Cox regression analysis determinedthe effect of several variables on survival or complications.
Results: After a mean follow-up of 50 months (range 19-239) 73/101 patients are alive (72.3%). Mean OS was 174.7 months ( 96.5% at 24 months;
83.7% at 60 months). Minor complications occurred in 17 patients and majorin 6. At 2 and 5 years 77.1% and 73.3% of patients were complication-free.
In multivariate analysis major and minor complications were not significantly
associated smoking habit, diabetes, obesity or vascular disease. Cosmetic
results were assessed by 84/101 patients and physicians, with good agreement on outcomes. Outcome was good/excellent in 57 (68%) self-evaluationand 58 (69%) physician evaluation and poor in the others, due not only tothe effects of RT but also to the technical limitations of breast reconstructive
surgery.
Conclusions: Unlike other reports, the present study showed that immedi-

S 303

ate breast reconstruction with expander/implant after mastectomy was associated with a low incidence of post-RT complications and a good cosmetic
outcome in the majority of patients, suggesting this approach is feasible evenfor patients requiring RT.
769 poster
POTENTIAL BENEFITS OF USING CARDIAC GATED IMAGES TO
REDUCE THE DOSE TO THE LEFT ANTERIOR DESCENDING
CORONARY DURING RADIOTHERAPY OF LEFT BREAST AND
INTERNAL MAMMARY NODES
C. E. de Almeida1 , N. Fournier-Bidoz1 , C. Massabeau1 , A. Mazal1 , P.
Canary2 , Y. Kuroki3 , C. François1 , A. Fourquet1 , Y. Kirova1
1
I NSTITUT C URIE, Paris, France
2
A LBERT E INSTEIN H OSPITAL, Sao Paulo, Brazil
3
CUCC-UFRJ, CDPI, Brazil
Purpose: To assess the benefits of using cardiac gated images for treatment
planning of breast and internal mammary nodes (IMN).
Materials: Inspiration breath hold CT series acquired at prospectively gateddiastolic phase were used for planning. Three different techniques were compared. Technique A used tangents and an IMN field covering the three 1rst
inter-rib spaces; technique B used an extended IMN including part of themedial breast in junction with tangential fields; the 3rd technique used helical tomotherapy. For each technique, two treatment plans were performed:
one plan (plan-01) where mean dose and V25 to the heart were considered
for plan evaluation and a second plan (plan-02) where LAD irradiation was
minimized.
Results: V25 to the heart was found to be < 5% for all 6 plans. Mean doses
to the heart were within 4.8 Gy to 7.2 Gy. By attempting to lower the dose to
LAD, heart Dmean was decreased by 20-30% for the two techniques A and
B while being unchanged for tomotherapy. Regarding target coverage, there
was no marked difference between plans where only heart dose was considered (plans-01) and plans where LAD dose was minimized (plans-02). When
LAD dose was part of plan evaluation, Dmean to LAD could be decreased by
24%, 19% and 9% for techniques A, B and tomotherapy respectively. The 3
techniques exposed segments of the left coronary to different levels of dose.
Conclusions: This study showed that evaluation of the dose to the LAD
coronary may change the treatment strategy. Cardiac gated images without
IV contrast permitted a good visualization of the coronaries in order to optimize the dose on these structures. In addition to heart V25, the dose to
the coronaries should be included in prospective studies on RT related heart
toxicity in association with all additional risk factors.
770 poster
PROGNOSTIC SIGNIFICANCE OF CARBONIC ANHYDRASE IX (CAIX) IN BREAST CANCER PATIENTS TREATED WITH RADIOTHERAPY
L. Beketic-Oreskovic1 , P. Ozretic2 , Z. Rabbani3 , I. Jackson3 , B. Sarcevic4 ,S. Levanat2 , P. Maric1 , Z. Vujaskovic3
1
U NIVERSITY OF Z AGREB , S CHOOL OF M EDICINE , U NIVERSITY H OSPITALFOR T UMORS , Department of Radiation Oncology, Zagreb, Croatia
2
RUDJER B OSKOVIC I NSTITUTE, Division of Molecular Medicine, Zagreb,
Croatia
3
D UKE U NIVERSITY M EDICAL C ENTER, Department of Radiation Oncology,
Durham, NC, USA
4
U NIVERSITY OF Z AGREB , S CHOOL OF M EDICINE , U NIVERSITY H OSPITALFOR T UMORS , Department of Pathology, Zagreb, Croatia
Purpose: The purpose of this study was to analyse tumor expression of carbonic anhydrase IX (CA IX) to evaluate this hypoxia marker as potential prognostic parametar for overall survival (OS) and relapse-free (RFS) survival inbreast cancer patients treated with radiotherapy.
Materials: Immunohistochemical expression of CA IX was analyzed onparaffin-embedded tumor tissues, obtained during surgery from forty female
breast cancer patients. The extent of CA IX expression was used to assess prognostic implication of this hypoxic marker on overall survival (OS)and relapse-free survival (RFS) in breast cancer patients. Relation of CA
IX expression and clinicopathological parametars was determined. All patients received standard adjuvant treatment including radiotherapy. Fisher’s
exact test, chi-square test, Spearman rank correlation coefficient, KaplanMeier univariate method and the Cox proportional hazards regression model
were used for statistical analysis.
Results: Patients with high CA-IX expression (above cut-off value) had ahigher occurrence of relapse (P=0.002). High CA-IX expression was significantly associated with shorter RFS (P<0.001, hazard ratio (HR) 0.21) andshorter OS (P<0.001, HR 0.19). High expression of CA-IX was associatedwith moderate to severe tumor necrosis (P=0.004) and positive lymph nodes(P=0.003). Among the lymph node negative patients and those with grade
II tumors it was possible to differentiate patients with better and worse prognosis based on the expression level of hypoxia marker CA IX. Lymph node
negative patients with high CA-IX expression had worse RFS (P=0.031, HR

S 304B REAST CANCERB REAST CANCER

0.14) and OS (P=0.005, HR 0.05). Within the subgroup of patients withgrade II tumors, those patients with high CA IX expression showed shorter
OS (P=0.046, HR 0.28). Multivariate analysis proved that high CA-IX expression was strong independent prognostic indicator for shorter OS (HR 4.14,
95% CI 1.28-13.35, P=0.018) and shorter RFS (HR 3.99, 95% CI 1.38-11.59,
P=0.011).
Conclusions: According to this study, elevated expression of CA IX wasan independent prognostic factor for decreased RFS and OS and a significant marker for tumor aggressiveness in breast cancer patients. We also
showed that the extent of CA IX expression was a strong prognostic factor
among node-negative breast cancer patients and those with grade II tumors,for which additional prognostic parameters are sometimes needed to determine optimal adjuvant therapy.Since hypoxia plays a significant role in tumor
sensitivity to radiotherapy, the implication of CA IX as a predictive marker
remains to be determined.
771 poster
QUALITY OF FORWARD IMRT PLANNING TECHNIQUE- COMPARISON OF 2 GROUPS OF BREAST CANCER PATIENTS PLANNEDAFTER 6 MONTHS INTERVAL
K. Antunac1 , V. Rajevac2 , M. Solaric2 , H. Sobat3
1
C LINICAL H OSPITAL "S ISTERS OF C HARITY "/U NIVERSITY H OSPITAL FOR
T UMORS, Department of Radiation Oncology, Zagreb, Croatia
2
C LINICAL H OSPITAL "S ISTERS OF C HARITY "/U NIVERSITY H OSPITAL FOR
T UMORS, Department of Radiotherapy, Zagreb, Croatia
3
U NIVERSITY H OSPITAL FOR T UMORS, Department of Radiation Oncology,
Zagreb, Croatia
Purpose: to compare the quality of planning technique at the introduction of
forward IMRT and 6 months later
Materials: patients with cancer of the left breast and negative axillary lymph
nodes after breast conserving surgery. Group 1 consists of 18 patientsplanned in March and April 2009 and group 2 consists of 23 patients planned
November and December 2009. Prescribed dose was 50Gy in 25 fractions.
PTV consisted of CTV (left breast) plus 1 cm margin; distance from skin surface was 5 mm. Required PTV coverage was 95-107% of prescribed dose.
Delineated organs at risk were lungs, heart and right breast; dose constraints
were V20< 35% for left lung and V20< 10% and V40< 5% for heart. Patientswere placed on Med-Tec MT-350 with both hands above head, head in forward position. For planning software XIO 4.3.1 with algorhytm resolution of0,2 cm was used. Statistical method: student t-test.
Results:

Statistically significant difference was observed in maximal dose and prescribed dose ratio, fraction of target volume that receives dose higher than
105% of prescribed dose, left lung volume that receives dose higher than
20Gy, and heart volumes that receive doses higher than 20 Gy and 40 Gy,
respectively. In patients in 2nd group higher dose homogeneity and betterlung and heart sparing was achieved.
Conclusions: 6 months after the introduction of forward IMRT quality of planning was upgraded, which resulted in better coverage of target volume andbetter sparing of organs at risk.

and 3DRT in patients with bilateral breast cancer after breast conserving therapy.
Materials: In our analysis we included ten bilateral breast cancer women, after breast conserving surgery dedicated for the further elective irradiation only
to the both breasts. Supraclavicular and axilla region were not irradiated. All
patients were irradiated to the total dose of 50 Gy in 2 Gy per fraction, fivetimes per week. For each patients three plans were generated: IMRT, 3DRT
- classical three dimensional tangential field radiotherapy, and RapidArc (Volumetric Modulated Arc Therapy), a novel version of IMRT. We analyzed dosevolume distribution for target volume as well as for normal tissue (lung andheart), we also calculated Conformality Index (CI).
Results: Mean CI for RapidArc was 0.92 (range 0.86-0.96), for IMRT 0.9(range 0.8-0.97) and for 3DRT 0.8 (range 0.84-0.92). Mean volume of thelung irradiated with the dose of 40 Gy for RapidArc, IMRT and 3DRT were:
11.2% (range 4.5% - 13%); 5.8% (range 3.0% - 7.4%); 6% (range 4.1% 9.4%) respectively. Mean volume of both lungs irradiated with ≥20Gy for
RapidArc, IMRT and 3DRT were: 47% (range 20% - 67%); 10.8% (range
9% - 12.5%); 12.1% (range 9.1% - 15.1%) respectively. Mean volume of theheart irradiated with the dose ≥40Gy for RapidArc, IMRT and 3DRT were
1.9% (0% - 4.7%); 0.6% (0% - 0.9%); 0.8% (0% - 1,5%) respectively.
Conclusions: Independently from the applied technique, in all comparedirradiation plans for the bilateral cancer of the breast high conformality index
were achieved. In all cases estimated volume of heart being irradiated tothe high doses for every technique, was low. In our analysis the essential
limitation for RapidArc standard use in all bilateral breast cancer patients islarge volume of the lung irradiated with the dose ≥20Gy. Further evaluation
is carried out for proper patients selection for such a treatment.

patients underwent surgical treatment by mastectomy. 253 patients have received preoperative HRT (7 Gy twice or 4-5 fractions by 5 Gy), 184 conventional preoperative (2 Gy by 20 fractions) and 192 postoperative radiotherapy
to the chest wall, axillary, supraclavicular and parasternal regions. 183 patients from preoperative group received irradiation of the parasternal lymph
nodes by the intraluminal brahytherapy using flexible Cf-252 sources pushed
in to the a thoracica interna (40 Gyeq at the distance 1 cm from centre axisof the Cf-252 source). The median interval after the RT to the developmentof the second cancer was 11.0 years (range from 8.1 to 19.7 years). The riskof developing a second cancer detailed analysis was carried out with respect
to age, disease stage, radiation technique.
Results: After 20 years of follow-up of any second malignancy, a second
cancer developed in 108 patients, in 47 cases of radiation-induced cancer
occurred more than 8 years after irradiation. 46 second cancer occurredfor HRT patients (17.9 %), 32 (17.4%) - for conventional radiotherapy. 26
cases (14,2%) of second cancer observed in HRT with intraluminal Cf-252
brachytherapy group. There were no cases of second lung cancer, althoughwere two cases of thyroid and one case of mediastinum cancer. During the5632 person-years of observation, the crude incidence rate of the second
cancer for HRT patients was 18.3 per 1000 person years, 20.0 per 1000 person years for conventional radiotherapy group. Hazard Ratio for the HRT, as
compared with simple schedules, was 0.82 (95% CI = 0.52-1.30, p>0.1).
Conclusions: Radiation therapy technique, such at use of preoperative hypofractionation radiotherapy well as the Cf-252 brachytherapy, had no influence on the risk of second breast or nonbreast cancer.

773 poster

STEREOTACTIC RADIOSURGERY FOR EARLY-STAGE BREASTCANCER: A NEW PARADIGM
C. Yu1 , S. Feigenberg1 , Y. Yu2 , M. Zheng2 , C. Wang2 , W. Regine1

SCINTIGRAPHIC EVALUATION OF MYOCARDIAL UPTAKE OF
99MTC-TETROFOSMIN IN PATIENTS WITH BREASR CANCER AND
LYMPHOMA
A. Tchakarova1 , A. Tzonevska2 , E. Piperkova2 , V. Parvanova3 , I. Marinova4
1
N ATIONAL H OSPITAL OF O NCOLOGY, Clinic for Radiation Therapy, Sofia,
Bulgaria
2
N ATIONAL H OSPITAL OF O NCOLOGY, Clinic for Nuclear Medicine, Sofia,
Bulgaria
3
N ATIONAL H OSPITAL OF O NCOLOGY, Clinic of Radiotherapy, Sofia,
Bulgaria
4
T ECHNICAL U NIVERSITY OF S OFIA, Department of Electrical Apparatus,
Sofia, Bulgaria
Purpose: Purpose: To evaluate the usefulness of myocardial scintigraphy
as a monitoring tool for early sign of chronic antracycline cardiotoxicity, thecurrent study define the relationship between myocardial uptake and washoutof 99m Tc-Tetrofosmin and pathological myocardial changes after antracycline
treatment
Materials: Material and method: We studied 64 patients: 32 with breast cancer and 32 with Hodgkin’s Lymphoma, mean age 47,3. Each patient passed
myocardial scintigraphy 30 min. and 3 hours after 99mTc-Tetrofosmin (740MBq) application. The tracer uptake in the early scan and washout in the latescan were calculated in % using ROI regions
Results: Results: All patients were divided into 3 groups: I group (control)13 patients without antracycline therapy and normal early myocardial scintigraphy; II group- 28 patients with antracycline therapy with cumulative dose up
to 450 mg/m2 and normal early myocardial scintigraphy and III group- 23 patients with antracycline therapy with cumulative dose up to 450 mg/m2 and visualized reversible hypoperfused defects during myocardial scintigraphy. The
mean tracer washout rates in group I (control) were 13,9%± 9; in II group21,01%±12; in III group-60,87%±13. The statistical analysis indicated significant difference in the tracer washout in group II and III, P<0,001. The mostprobable reason for that result is the mechanism of myocardial deterioration
after antracycline treatment.
Conclusions: Conclusion: 99m Tc-Tetrofosmin myocardial washout up to
50%, 3 hours after application, can be used as an indicator for early detectionof antracycline cardiotoxicity and therapy adoption in patients with antracycline treatment

772 poster
RAPIDARC, IMRT, AND 3DRT IN BILATERAL BREAST CANCERPATIENTS
K. Trela1 , D. Gabrys1 , R. Kulik2 , L. Michalecki1 , G. Glowacki1 , L. Misztal2
1
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , Department of Radiotherapy, Gliwice,
Poland2
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , Department of Radiotherapy Planning,Gliwice, Poland
Purpose: Radiotherapy in bilateral breast cancer patients is an challenge forclinicians during treatment planning. This difficult irradiation may be improved
with new modern techniques of radiotherapy such as IMRT or RapidArc. Estimation of usefulness of RapidArc irradiation technique in comparison to IMRT

774 poster
SECOND CANCER AFTER CF-252 INTRALUMINAL BRACHYTHERAPY OF THE PARASTERNAL LYMPH CHAIN FOR BREAST CANCERPATIENTS
A. Karklelyte1 , V. Atkocius1 , E. Aleknavicius1 , K. P. Valuckas1 , V.
Ostapenko1 , I. Kuzmickiene1
I NSTITUTE OF O NCOLOGY V ILNIUS U NIVERSITY, Vilnius, Lithuania

1

Purpose: In this study the incidence and clinical features of second cancer
occurring after preoperative hypofractionated radiotherapy (HRT) or postoperative radiotherapy for breast cancer was evaluated.
Materials: We conducted a long term retrospective cohort study of 629 patients treated by radiotherapy at our institute between 1987 and 1997. All

775 poster

1
2

U NIVERSITY OF M ARYLAND, Radiation Oncology, Baltimore MD, USA
X CISION M EDICAL S YSTEMS, Maryland, USA

Purpose: Stereotactic radiosurgery (SRS) has not been used for breast cancer primarily due to 2 reasons: 1) the lack of a suitable immobilization device
since the breast is a pliable organ; and 2) the lack of a SRS delivery systemthat can concentrate a high radiation dose non-invasively. We have developed
a dedicated SRS system which effectively addresses the two major obstacles
and demonstrated the dosimetric feasibility of simultaneously ablating the intact tumor and sterilizing the tumor bed.
Materials: A breast immobilization device consists of a solid outer cup withembedded stereotactic frame and a porous inner cup with a space between
the two cups; the two cups join at the chest wall side by a soft goggle-likelip for comfort. A negative pressure is applied to the space between the twocups to immobilize the breast tissues within the inner cup. 15 patients withsurgical clips in their breast underwent a geometric reproducibility trial using
an early generation immobilization device, in which the patients received two
CT scans spaced 10-60 minutes while wearing the cup. Between the twoscans, the patients got up from the table on their own and filled a questionnaire regarding the comfort of the immobilization cup. A SRS delivery system
uses 36 non-coplanar Co-60 sources which rotate around a focal point to produce 36 non-coplanar arcs. Two collimator sizes, 25mm and 15mm can beswitched dynamically. The breast cup is locked on the treatment couch withthe patient in prone position. The couch moves dynamically during treatment,
allowing the focal spots to "paint" the desired 3D dose distribution. The optimal motion trajectory is optimized by a dedicated treatment planning system
based on the dose prescriptions.
Results: The reproducibility of the 42 available clips was 1.83 mm +/- 1.08
mm (2σ ) and the patients reported good comfort. The SRS delivery unit installed at the University of Maryland has gone through rigorous geometricand dosimetric testing. With dynamic dose painting, the SRS system has
shown to be able to deliver high uniform doses to the target and simultaneously deliver a lower dose to the tumor bed. Fig. 1 shows a treatment plan
simultaneously delivering an ablative dose of 18Gy to an intact tumor plus a
3mm margin (CTV1: 3.2cm) and 10Gy to the tumor bed (CTV2 = CTV1+1cm).
The Dose-volume histogram shows very uniform dose coverage with 98% of
CTV1 receiving 18Gy and 100% of tumor bed receiving 10Gy. Only 21% of
the normal breast volume receives a dose greater than 5Gy. It is therefore
safe to deliver 3 fractions of such doses.

S 305

Conclusions: A breast specific SRS system has been developed. Planningstudies illustrated the feasibility of managing early stage breast cancer with
SRS. Clinical studies which will identify patients in whom current forms ofsurgery and postoperative radiation may be eliminated are planned, allowing completion of local therapy noninvasively within a few days rather thanmonths.
776 poster
THE PRELIMINARY RESULTS OF PHASE II STUDY: NEOADJUVANTCHEMOTHERAPY AND LOW-DOSE RADIOTHERAPY FOR BREASTCANCERL. Nardone1 , M. C. De Santis1 , D. Terribile2 , G. Mantini1 , G. C. Mattiucci1 ,G. Franceschini2 , A. Mulè3 , R. Masetti2 , V. Valentini1
1
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Radiotherapy Department, Roma, Italy
2
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Surgery, Roma, Italy
3
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Anatomical and Cellular Pathology, Roma, Italy
Purpose: Many in vitro studies have shown that there was a mayor radiosentivity for doses below 0.5 Gy. From 2009-2010 a phase II study was performed
in order to evaluate a benefit of this kind of association, in term of pathological complete response: an anticipated boost on the tumour was associatedto the neoadjuvant chemotherapy with " low dose fractions", for a total doseof 10 Gy.
Materials: We evaluated a group of patients, who received "Low-doseRadiotherapy"( 40 cGy photons twice daily for two days for 6 cycles on grosstumour volume + 0.5-1 cm margins by 3D conformal technique and tangential
fields as anticipated boost) and concomitant chemotherapy with anthracycline
and docetaxel in a neoadjuvant setting. The pathological complete response
was evaluated after surgery in terms of Tumour Regression Grade (Mandard’s
TRG).
Results: Seventeen patients, recruited from 2009 to 2010, were evaluated.
Were observed two patients with stage IIA (12%), fourteen with stage IIB(82%), one with stage IIIA (6%). Three patients had lobular cancer and fourteen ductal cancer. Median age was 51 years (range 30-70 yrs). The grading
was G3 in nine patients and G2 in eight patients. The median volume of
the tumour was 44 mm (range 22-80 mm). The patients received 6 cyclesof neoadjuvant chemotherapy based on pegylated liposomal antrhacyclinesand docetaxel. In the first and in the second day of chemotherapy the patients received low dose radiotherapy. Total dose was 960 cGy. This represented an anticipated boost. No acute skin toxicity was observed. Fourteenof the seventeen patients received conservative surgery; only three patients
had mastectomy. After surgery fourteen patients underwent radiotherapy onwhole breast (50 Gy/180 cGy) and four of fourteen underwent radiotherapy
on supraclavicular lymphonodes. Three of seventeen patients underwent an
adjuvant chemotherapy. The pathological complete response (TRG 1-2) was
observed in nine patients (53%); two (11.7%) had TRG 3 and six (35.3%) had
TRG 4-5.
Conclusions: Our data show that the use of "low dose radiotherapy" in association with neoadjuvant chemotherapy, as a boost on the tumour, seem toincrease the effectiveness of chemotherapy and the percentage of pathological complete response. A randomized phase II is planned.
777 poster
US-GUIDED&ENZYME-TARGETING
RADIOSENSITIZATIONTREATMENT (KORTUC II) WITHOUT ANY SURGERY FOR PATIENTSWITH BREAST CANCER OF STAGES I & II
Y. Ogawa1 , K. Kubota1 , M. Tadokoro1 , T. Yamanishi1 , N. Hamada1 , S.
Kariya1 , A. Nishioka1 , Y. Suzuki1 , N. Aoyama1 , M. Nogami1 , N. Yokota1 , T.
Sasaki1 , S. Yaogawa1 , A. Tsuzuki1 , R. Akima1 , K. Suzuki1 , S. Tokuhiro1
1
M EDICAL S CHOOL , KOCHI U NIVERSITY, Diagnostic Radiology Radiation
Oncology, Nankoku, JapanS 306B REAST CANCERB REAST CANCER

Purpose: Breast-conserving surgery has become the most popular surgicalprocedure for primary breast cancer. The siginificance of extended resection
has become less important, since the long term survival rate among women
who undergo breast-conserving surgery is the same as that among women
who undergo radical mastectomy. Thus, nowadays, local control is expected
to be minimally invasive on the basis that permanent curability is estimatedto be comparable. Various types of non-surgical ablation have been introduced as a local control for early breast cancer that also achieve cosmetic
gains. Recently we have developed a new enzyme-targeting radiosensitization treatment utilizing hydrogen peroxide (H2O2) & sodium hyaluronate for
intratumoral injection, Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas, Type II (KORTUC II) (Ogawa Y et al. Int J Oncol 34: 609-618, 2009),
and confirmed the safety & effectinveness of the treatment mainly for patientswith locally advanced neoplasms. Therefore, in the study, we applied KORTUC II for non-surgical treatment for patients with breast cancer of stages I &II.
Materials: KORTUC II radiosensitizer was used as an intratumoral injection
for breast cancer as approved by our local ethics committee. Since H2O2
is an irritant and may cause severe adverse effects, experimental studies
were performed prior to clinical application in order to ascertain safety ofthe method (Tokuhiro S et al. Oncol. Letters 1: 1025-1028, 2010). In order to allow long-acting radiosensitization of the local tumor tissue, sodium
hyaluronate was added to H2O2 in order to make the solution more viscousand to slow the degradation of the H2O2 (Tokuhiro S et al). The radiosensitizing agent was composed of 0.83% sodium hyaluronate & 0.5% H2O2, andwas prepared by adding 0.5 ml of 3% H2O2 solution (Oxydol; Ken-ei Pharmaceutical Co.Ltd., Osaka, Japan) to a commercially available disposable
syringe containing 2.5 ml of 1.0% sodium hyaluronate. H2O2 was added immediately before use in order to avoid degradation of the sodium hyaluronate
due to oxidation by H2O2. Thirty-five female stages I & II breast cancer patients (invasive ductal carcinomas) were enrolld in the KORTUC II trial. Eachpatient signed an informed consent form before participation in the study. Patients were eligible for the study if they had stages I & II breast cancer andhad either contraindication to general anesthesia due to significant comorbidity or had declined surgical treatment. Concerning radiation therapy (RT),hypofraction RT was given using a tangential field approach; energy level was
4 MV, total RT dose was 44 Gy, administered as 2.75 Gy/fraction, and 3 timesof electron boost of 3 Gy was added just following to 14th , 15th and 16th administration of 4 MV X-ray irradiation. A maximum of 6 ml of the agent was
injected into breast tumor tissue twice a week under ultrasonographic (US)guidance, just prior to each administration of RT. The injection of the agent
was started at the 6th fraction of RT. Patients with stage II breast cancer under 75 years old undertook systemic chemotherapy (EC and/or Taxan) prior
to the KORTUC II treatment, and patients with estrogen receptor-positive tumors also undertook hormonal therapy following KORTUC II.
Results: Treatment was well tolerated with a minimum of adverse effects.
All patients experienced mild local pain at the injection site. For 23 patients,
radiation-induced dermatitis was mild (grade I), and grade II for the other 12
patients, and almost equivalent to dermatitis induced by RT alone. All of
the patients achieved complete response and are alive without any distantmetastasis. Only one patient exhibited local recurrence at 34 months after
KORTUC II. Cosmetic results were excellent for 30 of the 35 patients. The
mean follow-up period at the end of November 2010 was 26.8 months.
Conclusions: KORTUC II represents a novel form of treatment using a new
radiosensitizer containing H2O2 & sodium hyaluronate that is injected intratumorally, mainly under US guidance. The treatment was well tolerated, with aminimum of adverse effects such as local pain at the injection site, and breastconservation treatmant without any surgical procedure was safely performedby the use of KORTUC II. The method is targeted at intrinsic peroxidase andcatalase present in tumor cells, infiltrating granulocytes, and contaminating
red blood cells in the tumor tissue. Therefore, it is considered to be a new
enzyme-targeting radiosensitization treatment potentially indicated for almost
every type of low-LET radioresistant neoplasm. Regarding use of the agent,
it is essential to avoid direct injection of the agnet into blood vessels and to
confirm even distribution of oxygen microbubbles throughout the tumor tissue using US or computer tomographic guidance. Hence, KORTUC II canbe considered as a new image-guided & enzyme-targeted radiosensitization
method. Because this radiosensitizer is effective and safe, and remarkably
less expensive than other methods, it has potential for worldwide and immediate use. In conclusion, KORTUC has great potential to become a viablenoninvasive replacement for surgical procedures and a valuable radiosensitizer for low LET-radioresistant neoplasms.
778 poster
USEFULNESS OF FIELD-IN-FIELD TECHNIQUE (FIF) IN WHOLE
BREAST RADIOTYERAPY -COMPARISON WITH STANDARD
WEDGED TANGENTIAL TECHNIQUE (WT) IN DOSIMETRIC ANDTECHNICAL STABILITYK. Kobayashi1 , H. Yamazaki1 , T. Tsubokura1 , N. Kodani1 , N. Aibe1 , M.
Hashiba1 , T. Nishimura1
K YOTO P REFECTURAL U NIVERSITY OF M EDICINE, Department ofRadiology, Kyoto, Japan1

Purpose: The aim of this study was to be able to implement the Field-in-Field

technique (FIF) in our daily practice for whole breast radiotherapy.
Materials: The data were obtained 40 Japanese breast cancer patients who
had undergone breast-conserving surgery (21 left-sided, 19 right-sided). Average of age, BMI were 54y.o. (range, 30-76) and 21.6 (range, 18.0-27.6). For
these patients the average planning target volume PTV volume was 267cm3(range, 117-675), PTV was defined as breast from the surface down to 5mm
depth. 4MV or 6MV photon beam from a Synagy Platform was used, motorized wedge were applied from 15-30 degrees. FIF and wedged tangent
technique (WT) plan were planned with Pinnacle ver.7.6c. The planning constraints were Maximum dose < 107% prescription, PTV mean dose > prescription. Organs at risk (OAR) were defined ipsilateral lung and heart. Central Lung Distance (CLD) and Maximum Heart Distance (MHD) were within
2cm and within 1cm. FIF and WT plans were compared for doses in PTV(mean dose and maximum dose), maximum dose area over 107% prescribed
dose, the monitor units required for treatment and treatment time. We assumed the prescription dose 200cGy per fraction. We assessed the dosestability of plans against inter- or intra- fractional organ motion.(Organ Mortion Test, OMT) For the assessment we make a plan one side field move
5mm posterior with the same MU. We evaluate the change of the PTV doseor maximum dose.
Results: Of 40 patients, 1 patient was cleared the dose regulation with nowedge or no subfield using multi-leaf collimator. The average of maximum
dose were FIF 213.5cGy (SD 0.27) vs. WT 217.1cGy (SD 2.01). The averageof PTV mean dose were FIF 201.8cGy (SD 1.25) vs. 201.3cGy (SD 2.20). FIF
achieved better homogeneity for PTV. SD of FIF was smaller than those of WT
technique. It means that FIF can achieve constant dosimetric result without
wide variety from individual difference. The average total MU of FIF vs. WT
were 234.4 (range, 228.6-244.5) vs. 359.5 (range, 278.5-500). From the MU
data, FIF could reduce treatment time 23.9 second (range, 7.5-51.3). In the
OMT study, the change of PTV mean dose were FIF -1.82cGy (SD 0.856) vs.
WT -0.52 (SD 1.23), the change of maximum dose were FIF -0.19cGy (SD1.28) vs. WT -0.04cGy(SD 1.56). This means FIF is more sensitive than WT
to the motion, but the change was very small for daily treatment.
Conclusions: The field-in-field provides much better dose distribution in the
PTV and irradiation area. And FIF can decrease MUs needed for treatment
and treatment time. But FIF is a little more sensitive to patient motion thanWT, it requires a little more accurate assumptions on patient motion and setup
reproducibility.
779 poster
UTILIZATION OF COMPUTED-TOMOGRAPHY DELINEATION OFREGIONAL LYMPH NODE IN BREAST CANCER RADIOTHERAPY.
T. Nageeti1 , Y. Khan2 , A. Saoudi3
1

PNOC-KAMC, M EDICAL C ITY, Department of Oncology, Jeddah, Saudi
Arabia
PNOC-KAMC, M EDICAL C ITY, Department of Oncolory, Jeddah, Saudi
Arabia3
PNOC-KAMC, M EDICAL C ITY, Medical Physics, Jeddah, Saudi Arabia
2

Purpose: This study aimed to assess the impact of Computed-Tomography(CT) delineation of supraclavicular/level III lymph node area (SC/III) on optimal prescribed dose coverage of regional nodal area in adjuvant radiotherapy
for breast cancer.
Materials: We retrospectively evaluated 14 consecutive breast cancer casesthat required SC/III lymph node areas irradiation as part of their adjuvant
radiotherapy. All patients were treated with single anterior beam (AP) anddose of 50Gy prescribed to 3cm depth. We repeated the plan prospectively
on all cases after we delineated the SC/III node areas on CT simulation slices
and we prescribed a dose of 50Gy by which at least 90% of the prescribed
dose (45GY) covers the SC/III delineated volume.
Results: We found that the average central depth of the delineated volumeof SC/III is 5.3 cm (2.3-7.2 cm). Of the delineated SC/III volume only 46% ±26.5 (± SD) covered by the 90% isodoseline when prescription to empiricaldepth of 3 cm was used. While using the delineated SC/III volume for planning achieved average target volume coverage of 98.8 % ± 1.1 by the 90%
isodose. In thirteen of the cases we needed to use 18MV energy to be able
to cover the volume adequately and on 3 of them a posterior beam were required to achieve the adequate dose coverage. The average field width was
6.5 cm vs 9.5 cm and field length 6 cm vs 6.5 cm for (new plan vs old plan).
Conclusions: Delineating SC/III volume on CT for planning adjuvant nodal
irradiation for breast cancer is mandatory to be able to choose appropriate
energy, to achieve adequate target dose coverage and to avoid treating unnecessary tissue.

780 poster
VERIFICATION OF DIFFERENT IMMOBILIZATION DEVICES FOR
RADIOTHERAPY TO BREAST OR CHEST WALL IN PATIENTS WITH
BREAST CANCER.
J. Topczewska-Bruns1 , D. Kazberuk1 , C. Jurczykowski1 , K. Bielicki1 , E.
Rozkowska1 , T. Filipowski1
1
C OMPREHENSIVE C ANCER C ENTER, Department of Radiotherapy,
Bialystok, Poland
Purpose: Radiotherapy is essential in breast cancer treatment. Reproducible
patient’s (pts) immobilization is necessary to precise dose delivery during radiotherapy. The aim of the study was to estimate number, magnitude anddirection of any displacements of tangential fields (TF) after breast conservative treatment (BCT) and mastectomy (M) pts irradiated on 2 immobilization
system: breast board (BB) or All-In-One System (AIO).
Materials: On the BB the upper part of the body was elevated for 10 degrees above the couch level and on AIO pts were lying flat on the base plateof device. All TF were simulated in accordance with digital reconstructedradiographs deriving from treatment planning CT scan. The portal images
obtained on accelerator were compared with the reference images. Displacements in mm were recorded for horizontal (H) and vertical (V) directions anddegree of field rotation (R) was noted. The results are presented as mean
and SD. The percentages (%) of shifts in each direction below 5mm are also
reported.
Results: 1154 images of TF was analyzed - among those: 382 after M and
42 after BCT immobilized on BB and 690 after M and 40 after BCT on AIO.
For pts. with M treated on BB the mean and SD shifts in H, V and R directions were -1,2±3,23; -0,9±2,85; -3,9±1,59 and -0,3±4,3; -2,9±3,02;
0,9±3,34 for medial and lateral fields, respectively. The mean and SD shifts
in H, V and R directions were 0,1 ±2,6;1,2±2,74; -1,3±1,68 and -6±3,2;
2,6±2,17; 07±1,14 for medial and lateral fields after M immobilized on AIO,
respectively. For pts with BCT irradiated on BB the mean and SD shifts in H, V
and R directions were -0,7±3,04; 1,39±3,31; -0,15±1,57 and -0,78±3,16;
0,78±3,5; -0,25±1,63 for medial and lateral fields, respectively. Similarly,
the mean and SD shifts in H, V and R directions were 0,13 ±2,66; 1,3±4,19;-0,75±1,98 and 0,33±2,96; -1,34±2,84; 049±1,73 for medial and lateralfields after BCT treated on AIO, respectively. For pts irradiated on BB % ofcases in which mean displacements were below 5mm in H, V, R directions
were 82,9%, 95,2%, 99,4% and 87,5%, 90,8%%, 95,8% for medial and lateral fields after M and after BCT for medial field 92,7%, 91,2%, 100% and forlateral 92,9%, 90,8% and 99,4%. While for pts irradiated on AIO % of cases
in which mean displacements were below 5mm in H, V, R directions were100%, 90,5%, 100% and 86,4%, 95,5%, 100% for medial and lateral fields
after M and after BCT for medial field 100%, 90,5%, 100% and for lateral
91,7%, 100% and 100%.
Conclusions: Our analysis has shown that immobilization with BB an AIO
leads to some discrepancy in TF position in BCT and M pts. Displacements
below 5mm under 90% of portals measured are mostly expressed in H direction. The highest % of shifts along H,V and R directions below 5mm wasachieved for pts irradiated on AIO. This work has enabled us to evaluate theefficiency of 2 immobilization system. Differences in setup accuracy havebeen incorporated into preparing treatment plan for pts with breast cancer.
781 poster
VIRTUAL COMPUTER SIMULATION OF TIME DOSE FRACTIONATION EFFECT OF SKIN ERYTHEMA AFTER BREAST IRRADIATIONUSING BY NOVEL LQ MODEL
H. Sekine1 , C. Kanehira2 , K. Suzuki1 , Y. Kumazaki1 , Y. Otani1
1
S AITAMA M EDICAL U NIVERSITY I NTERNATIONAL M EDICAL C ENTER,
Department of Radiation Oncology, Hidaka, Japan
2
J IKEI U NIVERSITY S CHOOL OF M EDICINE, Radiology, Minato-ku, Japan
Purpose: The purpose of this study is to demonstrate computer simulation ofirradiated skin erythema, time course of which is supposed to be expressedby general linear quadratic (GLQ) model. GLQ model includes not only interfraction interval, but also time after irradiation. The model can express bothdivision cell death and apoptotic cell death.
Materials: Seventy-one of early breast cancer patients after breast conserving surgery, who were planned post-operative radiotherapy, were enrolled tothis study. Radiotherapy was delivered tangentially non-coplanar method in
2 Gy/fr with 4 -6MV photon beams, 5 fr/w until 50 Gy, and some patientswere given boost irradiation. Quantitative measurements of radiation induced
skin erythema have been detected using by reflectance spectrophotometer(CM-2500d, KONIKA-MINOLTA, Tokyo, Japan) every week until the end of
the radiation coarse. Follow up time after the therapy is 2weeks, 1 month andevery three months thereafter. Measured color is expressed by 3-dimentional
factors using L*a*b*: L* indicates lightness and a* and b* are chromaticity
coordinates. For the computer simulation, L*a*b* values were converted to
HSB (Hue, Saturation, and Brightness) values. The coefficients of α, β , andT1/2 are estimated by non-linear regression analysis of dose-effect plots of H,
S, and B, respectively. By the assumption that skin erythema will repair until
steady state, repair half time of skin erythema is obtained by iterative calcula-

S 307

tion. Accumulated doses were projected on time scale. Produced GLQ modelof each H, S, and B parameters simulates the appearance of skin erythema
during and after irradiation on the 3D breast graphic model. Software used inthis study is Mathematica ver. 7.
Results: Because S was increased according to dose accumulation, nonlinear regression curve of 1/S produced by fitting of inverted S data, andre-inversion of this curve induced regression curve of S (Fig). Nonlinear regression coefficients were got as follows: α/β = 3.88(H), 3.782(S), 1.9(B) ,doubling time=15, T1/2=12, Label Index=3%. Graphical simulation of skinerythema will be shown on the slides.

Conclusions: GLQ model can analyze Time-Dose Effect of fractionated irradiation along time scale. By this model, visual simulation of rise and fall of skinerythema during and after irradiation could be shown on screen. GLQ model
will be applied to the difference of survival between different split coarse ofradiotherapy, etc.
782 poster
WHOLE BREAST IRRADIATION USING THE RPM SYSTEM –BETTER COVERAGE OF THE TARGET: LEFT BREAST
V. Pyatigorskaya1 , H. Granot1 , M. Ben-Ayun1 , D. Elezra1 , R. M. Pfeffer1 , Z.
Symon1 , M. Ben-david1
1
S HEBA M EDICAL C ENTER, Radiation Oncology, Ramat-Gan, Israel
Purpose: Adjuvant RT for breast cancer (BC) reduces local-recurrence andimproves survival. Anterior position of the heart and baseline small lungvolume may compromise adequate dose coverage of the breast or nodes.
Deep inspiration is used to remove the heart from its anterior position andcreate higher lung-volume. The RPM (Real-Time Position management) system is a respiratory-gating device (Varian). Using an infrared tracking-camera
and a reflective marker, the system measures the patient’s respiratory patternand displays them as a waveform. Patient is directed to breath in repeatedly
steady normal respiratory volumes. For breast radiation, the gating thresholds were set for 80-100% inhale position, and radiation was delivered for that
breathing period repeatedly to the end of that fraction. The purpose of thisstudy was to compare treatment planning for left sided breast radiation using
the RPM system compared to normal breathing planning.
Materials: Between 5.2010-8.2010, 22 women with left sided BC and anterior
heart position were treated using the RPM system at the Sheba Medical Center. All women had normal-breathing CT-simulation (NBCT) and controlledbreathing simulation with the RPM system with 0.5 cm cuts. Treatment planning was optimized for both sets, with proper breast or chest-wall coverage(using ICRU 50 recommendations), limited to bilateral lungs volume of lessthen V20 of 32%, and no heart in treatment fields. 14 were treated also to
lymphatic basins including IMN. However, for the purpose of this study, only
breast and chest-wall were considered a target, and dose was calculated for
50 Gy in 2 Gy/Fx for all cases. Following IRB approval, data were collected
and analyzed to compare best treatment-planning of NBCT and RPM. Treatment areas were: 18 breasts, 2 reconstructions and 2 chest-walls.
Results: All patients in this analysis had anterior heart position with compromised breast coverage for protecting the heart. For each patient in the
NBCT, at least 3 cm of medial left breast area was not covered appropriately.
Median age was 48 years (range 30-65). Mean lung-volume was 1754cm(range 2980-1136) in the RPM group vs. 1104cm (2362-711) in the NBCT,
p=0.013. Maximal heart dose (measured for 2cm) was 1.7 and 1.5Gy, respectively, p=0.28, and heart V5 was also similar between groups. There was nodifference in V20, V10 and V5, maximal and mean lung-dose between thegroups (p=NS). Mean contralateral lung-dose was similar. Maximal side effects: grade-I in 15 and -II in 7.
Conclusions: For women with left-sided BC, using the RPM gating systemenabled better breast coverage without excess lung or heart dose. Lung vol-S 308G YNECOLOGICAL CANCERG YNECOLOGICAL CANCER

ume and heart dose were comparable between the techniques. This technique is now incorporated as treatment option for women with left-sided BC
who have anterior heart position for better breast radiation dose coverage.
783 poster“FEELING A WOMAN” WITH A BREAST CANCER: PRELIMINARY
EXPERIENCE.
A. Fiorentino1 , M. A. Carriero2 , V. Fusco1
1
I.R.C.C.S.- C.R.O.B., Department of Radiation Oncology, Rionero in
Vulture, Italy
2
I.R.C.C.S.- C.R.O.B., Department for Radiotherapy and Oncology,
Rionero in Vulture, Italy
Purpose: Women with breast cancer suffer from various treatment sideeffects: from surgery, to radiotherapy and chemotherapy; but all woman havepsychological and social symptoms. The aim of this study is To describe thesensation of "feeling like a woman" after diagnosis of breast cancer.
Materials: In our institution, we created a questionnaire for patients affectedby breast cancer. This questionnaire was divided into 3 items: Diagnosis,
Treatment and Tips for health professionals to improve the therapeutic courseof patients. In the section of Diagnosis and Treatment, we investigated about
the experience of patients (if they feel alone or have had the support of family
or otherwise, and if cancer experience has influenced the sensation "to be awoman").Patients (pts) affected by breast cancer and submitted to Quadrantectomy +/- chemo-ormonotherapy, compiled this questionnaire anonymously
during Radiotherapy.
Results: From March 2010 to November 2010, 24 Questionnaire werecompiled. Median age was 50 (range40-80 ), 60% received chemoormonotherapy. All pts received Radiotherapy with a standard total dose of
60 Gy (50 Gy + 10Gy boost).Questionnaire showed following:8,33% of pts
faced the diagnosis and treatment alone,8,33% had the support of medical
doctor,45,84% had the support of family, 25% Of husband, 12,5% of children.41,67% of pts were not longer able to look in the mirror because thescar is really a soul’scar and they didn’t feel "like a woman",8,33% of pts
didn’t feel "like a woman", but "the touch of husband" helped them.It was also
found that many women (29,2%) took inside anxiety and fear of not hurting
the family.In addition, pts asked for more psychological support not only forthemselves but also for family, demanded less bureaucracy and fast track theimplementation of instrumental tests.
Conclusions: In our experience the "total care" is the winning weapon in thefight against cancer. Patients should not and can not feel abandoned.

Gynecological cancer
784 poster
A REVIEW OF THE MANAGEMENT OF CERVICAL CANCER IN HIV
POSITIVE WOMEN IN ZIMBABWE
N. Tsikai1 , N. Ndlovu2
1
R ADIOTHERAPY C ENTRE , PARIRENYATWA H OSPITAL, Radiotherapy
Department, Harare, Zimbabwe
2
C OLLEGE OF H EALTH, Harare, Zimbabwe
Purpose: Cancer of the cervix is the most common cancer in Zimbabwean
women, occurring on a background of a high prevalence of HIV infection.
The purpose of the study was to define the burden of HIV infection in patients
presenting with concurrent conditions in our local population and discuss thepresentation, management and outcome of these women.
Materials: Retrospective review of patients with invasive cancer of the cervixand HIV infection referred to the Radiotherapy Centre, Harare from January
2007 to December 2008. Information was collected from medical records andanalysed using Epi-Info.
Results: A total of 258 women with invasive cancer of the cervix were evaluated and of these 80% (207/258) were tested for HIV. The HIV seroprevalence amongst the 207 women tested for HIV was 43.5% (90/207). Of the
90 HIV positive patients, 45.6% (41/90) had CD4 counts and 26% (34/90)
were on ARV therapy. The mean age for HIV positive women was 41.7 years.
Most patients 82% (74/90) had advanced stages of disease IIB to IVB. Radiotherapy (RT) was received by 60% (54/90) of patients and of these 55.6%(30/54) received RT with curative intent and 44.4% (24/54) received palliative
RT. Brachytherapy was administered to only 33.3% (10/30) of the patientsthat received RT with curative intent. External beam RT dose was escalated
to 60Gy to the whole pelvis in 23.3% (7/30) patients who did not receive
brachytherapy. Of the patients that received RT with a curative intent, 3 outof the 30 (10%) received chemoradiation as it was contraindicated in the rest.
Palliative RT for pelvic symptoms ranged from single fractions of 8 or 10Gy tohigh dose palliation of up to 60Gy in 30 fractions in 6 weeks. Treatment waswell tolerated by most patients. There was no report of toxicity during treatment in 63% (34/54) of patients. Treatment outcome was noted at 6 weeks

post-treatment for 78% (42/54) of the patients. The complete response ratein the 24 curative intent patients reviewed was 67% (16/24). In the palliative
RT group, 94% (31/33) of the reviewed patients achieved complete resolutionof symptoms at that time. Long term follow up was poor as only 10 patientswere seen at the one year review and of these 5 patients were in remission
and the rest were alive with disease.
Conclusions: The study revealed a high prevalence of HIV infection of
43.5%. Majority of these patients were unfortunately not on ARV therapy.
Most patients presented with advanced disease. Chemoradiation was contraindicated in a large number of patients because they were either not on
ARV therapy or had low CD4 counts. In the absence of brachytherapy, total
external beam dose escalation to 60 Gy at conventional fractionation was effective and well tolerated. The proportion of patients receiving palliative RT in
this group of patients was high. Palliative RT doses of 8 or 10Gy as a single
fraction achieved good palliation of symptoms.
785 poster
ANAEMIC SYNDROME CORRECTION IN PATIENTS RECEIVINGCHEMORADIATION THERAPY WITH EPREX FOR UTERINE CERVICAL CANCER
M. Fagim1 , S. Dina1 , D. Svetlana1
1
T HE R EPUBLICAN C LINICAL O NCOLOGIC D ISPENSARY, Ufa, RussianFederation
Purpose: of the present research is efficacy assessment of anaemic
syndrome correction in uterine cervical cancer patients (UCC) pharmacoradiologically treated with recombinant erythropoietin EPREX.
Materials: 63 newly admitted UCC patients (the median age 43.3 ±2.2
years) undergoing chemo-radiologic treatment were included into the list ofresearch participants. The combined radiotherapy was amplified by weekly
injections of 50 mg cisplastin up to the cumulative dose of 250 mg. The
anaemic syndrome was compensated with recombinant human erythropoietin epoetin alfa EPREX. In the course of four weeks 10 000 IU Eprex was
subcutaneously injected three times a week supplemented with oral administration of daily 200 mg Sorbifer Durules (Ferrous sulfate+Ascorbic acid ) ironpreparation. In order to determine the therapy efficacy,hemoglobin (Hb) level
and coagulation profile assessment measurements, as well as daily examination and inquiry of the patients and anaemic clinical symptoms evaluation,
were daily undertaken. The SF-36 Health Survey Questionnaire including
questions regarding both the physical and the psychological health components, with evaluation of symptoms intensity caused by the disease and its
treatment, was employed to estimate the effect of EPREX on the patients’ life
quality factors.
Results: Initially, Grade 1 anaemic syndrome (mild) was observed in 15(23.8%) patients, Grade 2 in 30 (47.6%) patients, Grade 3 in 12 (19.0%)
patients, Grade 4 (severe) in 6 (9.6%) patients. In 32 (71%) out of 45 Grade1,2 anaemia patients, Hb level was restored to the standard values, an improvement in the anaemia grade down to Grade 1 was observed in 8 (18 %)cases, whereas in 5 (11%) patients Hb level remained unchanged. Hb level
restoration in Grade 3, 4 anaemia patient groups up to the target values wasobserved in 9 (50%) patients, an increase in Hb level reaching Grade 1 in
3 (17%) cases, reaching Grade 2 in 6 (33%) patients. Analysis of the effect
EPREX exerted on life quality factors of UCC patients undergoing concomitant radio and chemo-radio therapy demonstrated anaemia correction to have
improved the overall quality of life, daily life activity level, and power level inall the patients. When enquired before the beginning of the anaemia therapy,
the patients complained of being weak and weary, feeling depressed, having sleep disturbances, memory impairments and dysorexia. Apart from thephysical health disorders, the patients’ psychological, social and emotional
functioning was disturbed. A significant improvement in overall social activity,
attitude of mind, appetite improvement and anxiety decrease were observed
following 4 weeks of treatment.
Conclusions: Thereby, therapy with epoetin alfa has proved to increase thelevel of Hb in UCC patients, irrespective of the anaemic syndrome severity
degree, following radio and chemo-radio therapy. The application of EPREX
has contributed to the improvement of the overall life quality in UCC patients
undergoing chemo-radio and radio therapy, due to normalizing Hb level values, 120 g/l and its lasting antianaemic effect.
786 poster
APOLIPOPROTEIN C-II AS A POTENTIAL BIOMARKER AND PROGNOSTIC FACTOR FOR LOCALLY ADVANCED CERVICAL CANCERAFTER RADIOTHERAPY
Y. Harima1
1
K ANSAI M EDICAL U NIVERSITY, Radiology, Moriguchi City - Osaka, Japan
Purpose: To determine the pretreatment serum protein level as a generally
applicable measurement in predicting and estimating the radiation treatment
outcome of patients with locally advanced squamous cell cervical carcinoma(CC).
Materials: In a screening study,we took the measurements twice: At first, 6

serum samples from CC patients (no evidence of disease [NED] 3, cancercaused death [CD] 3) and 2 from normal controls were tested. In the nextscreening test, 12 serum samples from different CC patients (NED 8, CD 4)
and 4 from normal controls were estimated. Subsequently, 28 different CC
patients (NED 18, CD 10) and 9 controls were analyzed in the validation study.
The samples were treated on protein chips, and the serum protein patterns
were detected by surface-enhanced laser desorption and ionization-time-offlight mass spectrometry (SELDI-TOF MS). Then, we used two methods forprotein identification of a peak: single MS-basedpeptide mass fingerprinting(PMF) method and tandem MS (MS/MS)-basedpeptide/protein identification
method. And then, the protein that best matches this peptidepeak was measured by a turbidimetric assay.
Results: The same peak 8918 m/z was identified in both screening studies. Neither the screening study nor the validation study had significant differences in the appearance of this peak in the controls and NED.However,
the appearance of the peak of CD was significantly lower than that of controls and NED in both screening study (p=0.02, p=0.04) and validation study(p=0.01, p=0.001). The protein that best matches this peptide8918 m/z peak
was identified as Apolipoprotein C-II (ApoC-II) using PMF and MS/MS methods. The mean levels of ApoC-II in serum using a turbidimetric assay showeda tendency to decrease with CD group than that of NED group (p = 0.051).
Conclusions: ApoC-II could be used as a biomarker for detection in predicting and estimating the radiation treatment outcome of patients with CC.

S 309

full local regress of a tumor became at a complete recovery low signal on
2WI from cervical stroma, and presence in stroma indistinctly outlined sitesof the raised signal was regarded as partial regress of a tumor with presence
residual tumoral infiltrations (drawing 2).

787 poster
APPLICATION OF TECHNIQUES OF COMPLEX MEDICAL VISUALIZATION IN AN ESTIMATION CHEMO RADIATION THERAPY OF THE
CERVICAL CANCER
Z. Telguziueva1 , V. Philippenko1 , Z. Zholdybay1 , F. Aupov1 , S. Kim1
1

T HE K AZAKH SCIENTIFIC RESEARCH INSTITUTE OF ONCOLOGY AND

RADIOLOGY, Brachytherapy Department, Almaty, Kazakhstan

Purpose: Estimation of the efficiency of chemo radiation therapy of patientswith the cervical cancer (CC) at use of modern radial diagnostics methods(the complex of special US-techniques and MRT)
Materials: Preliminary results of treatment of 36 patients of the cervical cancer with FIGO stages IIA IIIB who have been divided into 2 groups on a wayof medical influence are presented: the basic group (n=16) the patients, whohave received combined radiation therapy (RT) with application of cisplastin in metronomic chemotherapy regimens (40mg/m2 ) for 1-st, 8-th, 15-th,
22-nd, 29-th day of an irradiation; control group (n=20) - the patients who
have received radical course RT by the standard scheme. mbined RT in bothgroups was made the same and included sessions of the external beam radiation therapy (EBRT) on gamma-therapeutic devices (Teragam, Sirus) or
IMRT (linear accelerator Clinac-600) to total focal dose (TFD) for point B
of 40-46Gy and the intracavitary brachytherapy (BR) on gamma-therapeutic
complex Agate-VT by a doses 5Gy x 2 times a week to TFD at point A 4550Gy. Intravenous infusion of cisplastin in metronomic regimens throughout
5 weeks of an irradiation (a single dose 50mg, total course dose 250mg)
was spent on patients in the basic group during the combined RT. The average dose of RT was TFD (point A) 76.2Gy, TFD (point B) 58.2Gy. In
the control group the average dose of the RT was TFD (point A) 73.5Gy,
TFD (point B) 55.9Gy.The efficiency of the treatment was estimated in dynamics (before treatment was considered, at an irradiation dose 20Gy andafter treatment) by means of radial diagnostics methods - the complex of UStechniques (B-mode, tissue harmonic imaging, pre- and post-processing, amplitudes gystography, volumetry, Ultrasound Image on 3D-technology, Color
Doppler Imaging (CDI) and Power Doppler (PD)) and MRT of a small pelvis.
The following US-equipment is used SDU-1200, Viking 2400, GE Logic7; RT
is executed on GE Signa Profile tomograph with preliminary contrasting agent
omniscan (15.0 ml) x 30 minutes prior to research.
Results: The regress of initial volume of a tumor in the basic group (on the
average) - from 107.2cm3 to 4.0cm3 (according to US) and from 91.2cm3 to
3.6cm3 (according to RT) observed In the course of treatment; in the control group - from 68.7cm3 to 6.9cm3 (according to US) and from 90.6cm3
to 5.6cm3 (according to RT). The following more expressed destructive processes in a tumor were observed at US-monitoring carrying out in dynamics
of treatment in the basic group: change of tumors chostructure at the expense of increase of echogenicity; sound transmission decrease in a kind of
approach of a sclerosis; reduction of the topometrical indicators of a tumor of
the cervical cancer in 93.7% cases (the control group 70.0%); decrease indegree of pathological vascularization by the treatment end in 31.3% cases(in control group - the priority of a pathological blood-groove high (30.0%
has remained) and average degree (40.0%)); reduction of quantity of visualized vessels with the advent of avascularization zones at 68.7% of patients(the control group 30.0%); approach of an indicator of conditional densityof a tumor to value of density of a normal tissue at 68.7% of patients (thecontrol group 25.0%), drawing 1.The change of qualitative and quantitative
US-characteristics of a tumor of the cervical cancer observed at treatment
was characterized by approach of similar structural changes in a tumor at
RT-research. Therefore, anechogenic inclusions (the centers of necrosis) occurrence was observed at the big primary sizes of a tumor; more accurate
visualization of external contours of a tumor at the expense of reduction per
focal infiltrations specific and inflammatory character; the conclusion about

Conclusions: The received results show rather high efficiency of beam therapy of the cervical cancer at a combination with metronomic regimen of
chemotherapy with cisplatin. The obtained data testifies that application ofcomplex radial diagnostics methods are important not only in respect of specifying diagnostics of an oncological pathology, but also in respect of monitoring
for an estimation of efficiency of antineoplastic treatment.
788 poster
CD8 T-LYMPHOCYTES AND B-LYMPHOCYTES PREDICT RADIATION TOXICITY IN CERVICAL CANCER PATIENTS TREATED WITH
RADIOTHERAPY
P. C. Lara Jimenez1 , E. Bordon1 , L. A. Henríquez Hernández1 , B. Pinar1 ,C. Rodriguez-Gallego2 , M. Lloret1
1
H OSPITAL U NIVERSITARIO DE G RAN C ANARIA D R . N EGRÍN, Radiation
Oncology Services, Las Palmas de Gran Canaria, Canary Islands, Spain
2
H OSPITAL U NIVERSITARIO DE G RAN C ANARIA D R . N EGRÍN, Immunology
Department, Las Palmas de Gran Canaria, Canary Islands, Spain
Purpose: In the present study, we reported the role of CD4 and CD8 Tlymphocytes, B lymphocytes and Natural Killer cells in the prediction ofradiation-induced toxicity. Radiotherapy for cervical cancer consists of wholepelvic external beam radiotherapy (RT) and intracavitary brachytherapy. A
regimen of concurrent chemoradiation for definitive treatment of cervical cancer is widely used. Tumour control by RT requires the use of maximum dosethat can be delivered while maintaining a tolerance risk of normal tissue toxicity. Toxicity is a function of many controllable treatment-related variables: external beam technique; dose and fractionation; brachytherapy volume, doseand dose rate; and chemotherapy sensitisation of normal tissues. Different
predictive factors of tumour radiosensitivity have been described. Low levelsof radiation-induced apoptosis (RIA) in peripheral blood lymphocytes (PBL)
and late radiation toxicity have been shown to be correlated. Moreover, previous reports have suggested that PBL apoptosis could be used to identify
radiosensitive patients based on the apoptotic response of CD4 and CD8 Tlymphocytes.
Materials: Ninety-four consecutive patients and four healthy controls were
included in the study. The majority of patients had squamous cervical carcinoma (76.8%) in early stage of the disease (I (52.68%) II (41.20%)). A total
dose of 4550 gray (Gy) was administered in a 1.82 Gy/day schedule followed
by brachytherapy treatment at a dose of 20 Gy, to a total dose of 69.39 ±15.28 Gy. Toxicity was evaluated using the LENT-SOMA scale. The meanfollow-up was 26.14 ± 17.61 months (range 373). PBL subpopulations wereisolated and irradiated at 0, 1, 2 and 8 Gy. Apoptosis was measured by flow
cytometry.
Results: RIA increased with radiation dose and time of incubation, and data
fitted to a semi-logarithmic model defined by two constants: α (percentageof spontaneous cell death) and β (percentage of cell death induced at a determined radiation dose). Higher β values in CD8 and B-lymphocytes wereobserved in patients with low bowel toxicity (Hazard Ratio (HR) = 0.96, p =0.002 for B-cells); low rectal toxicity (HR = 0.96, p = 0.020; HR = 0.93, p =0.05 for B and CD8 subpopulations respectively); low urinary toxicity (HR =0.93, p = 0.003 for B-cells) and low sexual toxicity (HR = 0.93, p = 0.010 for
CD8-cells).

S 310Conclusions: We observed for the first time that B-lymphocytes can predictlate toxicity after 24 h of incubation. Feasibility and cost effectiveness of thisassay would favor larger studies to analyze the predictive role of this model.
789 poster
CONCURRENT CHEMORADIOTHERAPY WITH HIGH-DOSE-RATE
BRACHYTHERAPY FOR LOCALLY ADVANCED CERVICAL CANCER
Y. S. Kim1 , J. H. Kim1 , S. W. Lee1 , S. M. Yoon1 , S. D. Ahn1 , E. K. Choi1
1
A SAN M EDICAL C ENTER, Radiation Oncology, Seoul, Korea Republic ofPurpose: To evaluate the clinical outcomes of concurrent chemoradiotherapy with high-dose-rate brachytherapy (HDR-BT) and to identify prognostic
factors for uterine cervical carcinoma.
Materials: From 1999 to 2009, 328 patients with uterine cervical carcinoma
were treated with external beam radiotherapy (EBRT) and HDR-BT. The patients with FIGO stage ≤IIB received 41.4 Gy in 23 fractions of whole pelvic
EBRT followed by 35 Gy in 7 fractions of HDR-BT. The patients with FIGO
stage ≥IIIA received 50.4 Gy in 28 fractions whole pelvic EBRT followed
by 30Gy in 6 fractions of HDR-BT. The patients with para-aortic lymph nodemetastasis underwent extended field radiotherapy. Concurrent chemotherapy
was done in 254 patients (77%).
Results: The median follow-up period was 37 months for surviving patients.
The 5-year overall survival (OS) and cause specific survival (CSS) rates were
71% and 74%, respectively. The 5-year disease free survival rate was 71%.
The 5-year OS rates were 76% for Stage I disease, 74% for Stage II disease,and 61% for Stage III patients. The 5-year locoregional relapse-free survival
rates were 98%, 87%, and 76% for patients with Stage I, II, and III patients,
respectively. In multivariate analysis, tumor size (p=0.002) and presence ofpara-aortic lymph node metastasis (p=0.017) were significant prognostic factors for CSS, and tumor size (p=0.010) for locoregional control. Forty-six
patients (13%) experienced acute grade 4 toxicities, including mainly hematologic toxicity. Thirteen patients (4%) developed late grade 3 complications.
Planned treatment was completed in ≥ 90% patients.
Conclusions: The present study suggested that our treatment schedule of
EBRT and HDR-BT was effective and tolerable, and late complications were
acceptable. Tumor size was significant prognostic factor for CSS and local
control, and para-aortic lymph node metastasis for CSS.
790 poster
CORRELATION BETWEEN DEFINED VOLUMES WITH OR WITHOUTPET/CT IN GYNECOLOGICAL BRACHYTHERAPY
S. Meregalli1
1

G YNECOLOGICAL CANCERG YNECOLOGICAL CANCER

A.O. S AN G ERARDO, Department of Radiotherapy Oncology, Monza, Italy

Purpose: Concomitant chemoradiation with cisplatinum and intracavitarybrachytherapy is the standard of care in patient with locally advanced cervix
cancer. Treatment planning for brachytherapy provides for the use of three
dimensional imaging, such as CT scan or MRI. Positron Emission Tomotherapy with [18 F]FDG is an imaging modality that can aid in image-guided radiation treatment planning, in fact, is currently used in staging and restaging of this malignancy. The aim of this study is to estimate the feasibilityof this method and added benefit of employing PET/CT in gynaecologicalbrachytherapy image-guided radiation treatment planning.
Materials: From January 2007, at Radiation Department of San Gerardo
Hospital of Monza, nine patients with advanced cervical carcinoma wereenrolled in this study. All patients underwent external beam radiation therapy (EBRT) to whole pelvis (box technique with four shape-field; 1.8 Gy
per fraction to a total dose of 50.4 Gy) with weekly concomitant cisplatinum
chemotherapy (40 mg/m2 ). HDR brachytherapy has been performed weekly
during the course of pelvic radiation therapy, starting in the third week of
EBRT (5 Gy per fraction; 5 to 6 fractions). The HDR brachytherapy fractions
have been planned with CT scan except the first and the fourth fraction forwhich FDG-PET/CT was employed.
Results: In this study PET-defined target, the so called BTV that includes
both the clinical target volume as defined by CT and PET positive areas, andCT-defined target volumes during the first (for nine patients) and the fourth(for six patients) fraction have been analysed. A good linear correlation has
been observed between PET-defined volumes and CT-defined volumes with
R2 = 0.85 (R2 = 0.85 for first fraction volumes and R2 = 0.88 for fourth fraction
volumes).
Conclusions: The main goal of our analysis could be to define, after anadequate follow-up, the site of possible recurrence: the recognition of a local
relapse in the BTV area may suggest the necessity of escalated local dose.
791 poster
DOSIMETRIC EVALUATION OF IMPACT OF BLADDER FILLINGSTATUS ON THREE DIMENSIONAL DOSIMETRY (3D - DVH) IN
HIGH-DOSE-RATE INTRACAVITARY BRACHTHERAPY (HDR - ICBT)WITH TANDEM-RING APPLICATION FOR CERVICAL CANCERS
S. Kumar1 , U. Mahantshetty2 , S. Roy1 , S. Jamema3 , R. Engineer1 , S.
kadam3 , D. deshpande3 , S. K. Shrivastava1
1
TATA M EMORIAL H OSPITAL, Department of Radiation Oncology, Mumbai,
India
2
TATA M EMORIAL H OSPITAL, Mumbai, India
3
TATA M EMORIAL H OSPITAL, Department of Medical Physics, Mumbai, India

Twenty patients (22.5%) presented with Grade 1- 2 urinary or bowel toxicity
and 40 patients (45%) with Grade 1-2 vaginal toxicity.
Conclusions: Despite the majority of locally advanced carcinoma, excellent
local and regional control rates were achieved with an acceptable rate of late
toxicity. Dose volume optimization resulted in a higher dose to the target
volume and a better local control.
793 poster

Purpose: To investigate the effect of bladder filling on 3D DVH parametersand determine an optimum bladder volume during HDR-ICBT in Cervical cancers.
Materials: In this dosimetric study, 22 patients who underwent HDR-ICBT
with CT/MR compatible applicator as a routine treatment were invited for thisstudy. Each patient underwent CT planning with bladder emptied (series 1),
after 50 ml filling (series 2) and 100 ml filling (series 3). Bladder filling wasdone with a saline infusion through the bladder catheter. Contouring for bladder, rectum, sigmoid and small bowel in all series and patients was done.
Treatment planning was performed on all the three series for each patient on
the Eclipse Planning System (Version 8.1; Varian Medical Systems). Treatment planning was done with 7 Gy to point A prescription with the standard
loading patterns. Dose Volume Histogram (DVH) for bladder, rectum andsmall bowel were obtained. Recommended 3D - DVH Parameters (0.1 cc,
1 cc and 2cc doses) and for lower doses and larger volumes 5 cc, 10 cc
and mean doses to the OAR’s were noted. All the doses were converted to
EQD2 levels (a/b = 3 for OAR’s) and analyzed. Paired t tests and Pearson
correlations analyses were performed.
Results: The mean (+ SD) bladder volume was 65 (+ 25) cc, 118 (+ 28) cc
and 170 (+ 28) cc, for series 1, 2 and 3 respectively. Similarly, the mean
rectal, sigmoid and small bowel volume for all series were comparable The
1cc, 2cc, 5cc and 10cc mean bladder doses for series 1 and 2 were similar
at 17, 14, 10 & 8 Gy EQD2 respectively, while for series 3 they were 18, 15,
11 & 8 Gy EQD2. However, there were no statistically significant differencesin the mean across all the series (series 1 Vs 2; 2 Vs 3 & 3 Vs 1), although
there was trend towards higher bladder doses in series 3. Similarly, for small
bowel region, the 1cc, 2cc and 5 cc mean doses for series 1, 2 and 3 were
6.5, 5.5, & 4, 5.6, 4.7, & 3.5 and 4.8, 4 & 3 Gy EQD2 respectively. There
was a significant increase in the small bowel doses with series 1 (empty) as
compared to series 3 (p< 0.01), while there was trend towards higher doseswith series 2 as compared to series 3 (p = 0.07) and no significant difference
between series 1 and 2 over small bowel doses. However, the rectal andsigmoid doses were not significantly affected with either series.
Conclusions: Bladder filling protocol was well tolerated by all patients. A
reasonably reproducible bladder volume was achieved in all patients. In our
analysis so far, there is no significant impact of bladder filling on bladder DVH
parameters although larger bladders tend to have higher doses. Small bowel
doses are lesser with higher bladder volumes. Further evaluation and validation is necessary.
792 poster
DVH PARAMETERS AND CLINICAL OUTCOME IN CERVICAL CANCER PATIENTS TREATED WITH 3D IMAGE GUIDED
BRACHYTHERAPY
H. Janssen1 , M. De Brabandere1 , A. Nulens1 , C. Sweldens1 , E. Van
Limbergen1
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Radiation
Oncology, Leuven, Belgium
Purpose: To report our 7 years’ experience of chemoradiotherapy for cervical cancer with MRI (or CT) guided brachytherapy using the tandem-ovoid
applicator
Materials: Eighty-nine patients with cervical cancer stage IB-IVB weretreated in our institute between 2002 and 2009. All patients received external beam radiotherapy +/- chemotherapy followed by a Pulse of Low Dose
Rate brachytherapy boost. MRI or CT images were taken with the applicatorin situ. The first 16 patients were treated according to traditional X-ray-basedplans. High-Risk CTV, Intermediate-Risk CTV, bladder, rectum and sigmoid
were retrospectively contoured. In all other patients, treatment plans weremanually optimized after delineation of the target volumes and organs at risk
at MRI or CT. Doses were converted to the equivalent dose in 2 Gy (EQD2)
by applying the linear quadratic model. The median age of the patients was
57 years (range 28-88). Most patients (87%) had locally advanced disease.
Of the 89 patients, 26 had pelvic and 16 lumbo-aortic lymph node involvement. In 5 patients the intracavitary technique was combined with interstitialbrachytherapy.
Results: The mean D90 and D100 for the High-Risk CTV were 83 +/- 9.2 Gy
and 66.5 Gy +/- 6.5 Gy with a mean D90 of 76 Gy for the first 16 patientscompared to 84.5 Gy for the other patients. Mean D90 and D100 values for
the IR CTV were 69 +/- 5.2 Gy and 58 +/- 3.9 Gy. At a median follow-up of
27 months (range 8-77 months), the 3 year local control rate for all patientswas 95%, the regional control rate 88% and metastasis free survival rate 78%. Local recurrence rate was 12.5 % in the first 16 patients compared to
2.7% in the second patient group. Five patients (5.6 %) developed grade 3
or 4 gastro-intestinal toxicity. No grade 3-4 genito-urinary toxicity was found.

FDG-PET CT SCAN BASED NODAL STAGING AND OUTCOME IN
ADVANCED CARCINOMA CERVIX.
M. Upasani1 , U. Mahantshetty1 , V. Rangarajan2 , M. Thakur3 , N.
Purandare2 , S. Chopra1 , R. Engineer1 , A. Maheshwari4 , R. Kerkar4 , S. K.
Shrivastava1
1
TATA M EMORIAL H OSPITAL, Department of Radiation Oncology, Mumbai,
India
2
TATA M EMORIAL H OSPITAL, Department Of Bio-Imaging, Mumbai, India
3
TATA M EMORIAL H OSPITAL, Department of Radiodiagnosis, Mumbai, India
4
TATA M EMORIAL H OSPITAL, Department of Gynaecologic Oncology ,Mumbai, India
Purpose: Nodal staging is not a part of Clinical FIGO staging in cervicalcancer. However, nodal disease is an independent prognostic factor for outcome. Newer imaging modalities including MR and FDG PET-CT have been
evaluated for the same. We evaluated the utility of FDG PET-CT in Advanced
Carcinoma Cervix in a prospective study. One of the aims was to study theincidence of nodal involvement with FDG PET-CT and their outcome and isbasis of this report.
Materials: In this prospective observational study, 103 patients underwent
screening and serial follow-up FDG PET-CT scans from September 2005 to
December 2008. All patients underwent pre treatment USG and / or CT abdomen pelvis and MRI and FDG PET-CT followed by radical chemo-radiation.
MRI & FDG PET-CT was done as per the institutional protocol. Follow-up
surveillance FDG PET CT was done for these patients at 6 months interval.
Results: Of the 103 patients, 62 were FIGO Stage IIB (60%) and 41 were
FIGO Stage IIB (40%). Conventional imaging identified nodes in 63 patientswith 44 having pelvic nodes, 16 patients with pelvic and para-aortic nodes
and isolated para-aortic nodes in 3 patients. Similarly, FDG PET-CT identified
nodal disease in 69 patients, with pelvic nodes in 44 patients, pelvic and paraaortic in 22 patients and isolated para-aortic nodes in 3 patients. The mean(±SD) SUV value for pelvic nodes was 6.9 (±4.2) and for the para-aortic
nodes 8.8 (±10.1). FDG PET-CT identified additional pelvic nodal disease in
18 patients, additional para-aortic nodes in 12 patients who were not detectedon conventional imaging. All patients underwent tailored treatment with radiation. With a median follow-up of 28 months (12 60 months), out of 103, 35
patients had recurrence or residual. 6 patients were deemed lost to followup. Follow-up PET-CT scans identified 27 patients with recurrences. By FDG
PET-CT based nodal staging, 6 recurrences (3 loco-regional; 3 had local withpara-aortic or distant metastasis) was seen in node negative patients while 29
recurrences were seen in node positive patients (4 loco-regional; 14 had local with para-aortic and/or distant metastasis, 4 had para-aortic nodes only, 7
had only distant metastasis). Patients with only para-aortic or solitary distantmetastasis received further radical treatment successfully.
Conclusions: FDG PET-CT identifies additional pelvic and para-aortic nodes
in advanced carcinoma cervix. It assists in optimization of the treatment. The
outcome in patients with FDG PET-CT node positive is poor as compared
to node negative patients. Further follow-up and larger studies required toconsolidate its impact.
794 poster
HDR BRACHYTHERAPY FOR CARCINOMA OF THE UTERINECERVIX: DIFFICULTIES IN THE INSERTION WITHOUT ANESTHESIA
R. J. Miechi123 , C. Porrato1 , J. Piccinini1 , F. Maini1 , G. Tuttolomondo1
1
R ADIOTHERAPY C ENTER “D R . J OSÉ M IECHI ”, Rosario, Argentina
2
P ROVINCIAL C ENTENARY H OSPITAL, Rosario, Argentina
3
M EDICAL S CHOOL , R OSARIO N ATIONAL U NIVERSITY, Department of
diagnostic imaging and radiotherapy, Rosario, Argentina
Purpose: The aims of this retrospective study, for cervical cancer in patientspreviously treated with external beam irradiation, were to evaluate the difficulties to insert the brachytherapy applicators into the uterus without pain, orslightly unpleasantly, when no anesthesia nor sedation was used.
Materials: 1096 patients treated from October 1995 to October 2010 for cervical carcinoma with HDR using a remote afterloading system, total 5480 insertions, were reviewed. Treatments were performed with a Nucletron Microselectron HDR UPS V11.22 with an Ir-192 source. Dose optimization points
were initially located along a line 2 cm lateral to the tandem, beginning at the
tandem tip at 0.5-cm intervals, ending at the tail, and optimized to 100% of thepoint A dose. There were 14.8% Stage Ib patients, 15.5% Stage IIa, 38.7%
Stage IIb, 14.0% Stage IIIa, and 17.0% Stage IIIb. The median age was 50(23-81). Radiotherapy consisted of external beam irradiation (LA-Co60) to the

S 311

pelvis (mean dose of 45-50 Gy), combined with HDR brachytherapy (meandose of 30 Gy to point A) given, 6 Gy per session twice weekly or 7 Gy twice
weekly. The applicators were 4 and 6cm tandem lengths, and 2.0, 2.5 and3.0cm ovoid diameters. When to insert the aplicators was impossible, only
vaginal ovoid was used in spite of not having given the recommended doses.
The procedure took place without anesthesia or sedation.
Results: 43 patients (3.9%) were found with difficulties in the insertion, 39 ofwhich, whose anatomy had also been severely modified by external irradiation, were advanced stages (IIb, IIIa or IIIb). The rest were in pain.
Conclusions: Anesthesia or sedation can be avoided in HDR brachytherapy
treatments for cervix cancer. Only a few patients, in pain or advanced stage,would need anesthesia to reach recommended doses.
795 poster
IS FDG UPTAKE IN CERVICAL TUMOURS PREDICTIVE OFOUTCOMES IN CERVICAL CARCINOMAS TREATED BY RADIOCHEMOTHERAPY?
J. CHAMOIS1 , K. Peignaux1 , M. Liegard-Gauthier2 , A. Berriolo-Riedinger3 ,G. Truc1 , N. Blanchard1 , A. Ligey1 , F. Bonnetain2 , G. Crehange1 , P.
Maingon1
1
C ENTRE G EORGES -F RANÇOIS L ECLERC, Department of Radiation
Oncology, Dijon, France
2
C ENTRE G EORGES -F RANÇOIS L ECLERC, Department of Biostatistics,
Dijon, France
3
C ENTRE G EORGES -F RANÇOIS L ECLERC, Department of Nuclear Medicine,
Dijon, France
Purpose: To determine whether cervical tumour uptake of 18-Fluoro-deoxyglucose (18FDG) measured as the maximal standardized uptake value (SUVmax) is a relevant prognostic factor of tumour response to radiochemotherapy(RCT) at 45 Gy, at treatment completion and of patients’ outcomes.
Materials: We retrospectively reviewed the cases of 45 patients treated by
RCT and intracavitary pulse-dose-rate (PDR) brachytherapy (BT) for locallyadvanced cervical carcinoma.All of them had cervical MRI, 18 FDG PET atdiagnosis, and clinical assessment and MRI at 45 Gy. Tumour response was
evaluated at treatment completion. The largest diameters of the tumour on
the first and second MRI, SUV max, and routinely used prognostic factors
were recorded.
Results: Stage distribution was (using FIGO): IB 11%, IIA9%, IIB 62% and
IIIB 18%. The mean pretreatment SUV max was 10 (0- 21) and was higher
when pelvic nodes were involved (13.4 vs. 8.9, p=0.03). The mean tumour
volume measured on the first MRI was 45.2 cm3 (6.5-154). Patients received
RCT delivering 45 Gy in 5 weeks on the PTV, concurrent weekly chemotherapy, and BT delivering a median dose of 30 Gy (range 15-45 Gy). At 45 Gy:
the mean tumour volume regression measured on MRI was 82%. According
to RECIST, 36% of patients achieved complete tumour response, 53% partial
response, and 11% stable disease. FIGO stage predicted global response at
45 Gy according to RECIST (p=0.006), but SUV max did not. At treatmentcompletion: the global response to RCT at 45 Gy was the only significant
predictive factor of complete response (OR=26, 95% CI= [1.8 376], p=0.02)
in univariate analysis. With a median follow-up of 27 months, the two-year actuarial overall survival and relapse free survival were respectively 84 % and82%. In univariate regression analysis, lymph node involvement was the only
significant prognostic factor for relapse (OR=8.7, CI95% [1.1-65.9], p=0.036).
Using a cut-off value of 10 for SUVmax, we found that patients with SUVmax< 10 tended to have a lower risk of relapse than those with SUV max >10.
Conclusions: SUV max correlated with pelvic nodal involvement. However,
FIGO staging, pelvic nodal status, and tumour regression assessed by MRI
following RCT at 45 Gy were more accurate than SUV max in predicting response to treatment and failure.
796 poster
MOTION AND VOLUME CHANGES OF PELVIC LYMPH NODES INCERVICAL CARCINOMA PATIENTS TREATED WITH CHEMORADIATION: WHAT MARGINS ARE REQUIRED?
M. Schippers1 , G. Bol1 , B. Raaymakers1 , H. Verkooijen2 , U. van der
Heide1 , A. de Leeuw1 , I. M. Jürgenliemk-Schulz1
U NIVERSITY M EDICAL C ENTER U TRECHT, Department of Radiation
Oncology, Utrecht, Netherlands
2
U NIVERSITY M EDICAL C ENTER U TRECHT, Department of Radiology,
Utrecht, Netherlands

1

Purpose: To investigate the weekly volume changes and motion of enlarged
lymph nodes in patients with cervical cancer treated with chemoradiation.
Margins were derived to accommodate the changes and it was evaluatedwhether the clinically used treatment margins were sufficient.
Materials: 17 patients with cervical cancer FIGO stages 1B-3B with enlarged
pelvic lymph nodes (short axis more than 5 mm) were treated with a combination of IMRT external beam radiotherapy, PDR brachytherapy and weekly
Cisplatin. All patients underwent MRI examination before and weekly during the external IMRT treatment. A total of 39 lymph nodes were delineatedS 312G YNECOLOGICAL CANCERG YNECOLOGICAL CANCER

on the T2-weighted sequences. Weekly volumes were measured and volume
changes were calculated. By overlaying all delineations on a master CT scan,
the margins in the six main directions (medial, lateral, anterior, posterior, superior and inferior) were manually derived with respect to the pre-treatment
images to encompass the variations in nodal motion, nodal volume differences and our institutional registration error. We validated our margins withthe margins derived with an in-house developed computer program. Nonparametric Wilcoxon test was used to test for statistical differences in volumes
and margins over the course of the treatment
Results: All but one node showed regression in volume during treatment.
The median nodal volume decreased significantly (p<0.001) and was 0.99
[0.30-8.06], 0.92 [0.17-8.22], 0.67 [0.17-9.74], 0.49 [0.07-10.68] and 0.34 [05.52] cm3 on the pre- and 1, 2, 3 and 4 weeks post treatment scans respectively. Around the pre-treatment nodal volume a margin of 8, 5, 7, 8, 7 and 9mm was needed in the medial, lateral, anterior, posterior, superior and inferior
direction to encompass 95% of the lymph nodes over the 4 weeks of treatment (see graphic). The median margins needed to encompass the nodes inweek 4 were in all directions significant smaller than these maximal margins.

Conclusions: For 39 enlarged lymph nodes weekly volumes were measured
and inhomogeneous margins were derived around the pre-treatment nodal
volume to accommodate for changes in motion and volume. In our clinicalroutine we can safely operate with a homogeneous margin of 1 cm aroundthe nodal pre-treatment volume, bearing in mind the average reduction of thelymph nodes during the course of treatment. However, the choice of margins
is dependent on the treatment technique used for nodal irradiation and theposition verification method.
797 poster
NEW TECHNIQUE TO AVOID GENERAL ANESTHESIA DURINGCERVIX CANCER BRACHYTHERAPY
A. Hassouna1 2
1KING FAISAL S PECIALIST H OSPITAL & R ESEARCH C ENTER , Oncology
Department, Radiotherapy Unit, Jeddah, Saudi Arabia
2
N ATIONAL C ANCER I NSTITUTE , C AIRO U NIVERSITY, Radiation Oncology
Department, Cairo, Egypt
Purpose: To keep the cervical canal dilated after the first high dose rate(HDR) brachytherapy fraction avoiding general anesthesia for subsequent applications.
Materials: In the first HDR brachytherapy application: cervical dilatation was
done under general anesthesia. The proximal 4 cm of 3-way urinary Foley catheter was cut (new cervical sleeve), inserted into the cervical canaland fixed by 3 simple sutures. Uterine tandem was inserted into the uterus
through the new sleeve and procedure was completed as usual. The newsleeve was left in place after the 1st session keeping the cervical canal dilated in between the HDR brachytherapy applications.
Results:

In total: 9 HDR brachytherapy applications were done for 3 cancer cervix patients. For each patient: first application was done under general anesthesia
while 2nd and 3rd applications were done without general anesthesia (analgesia or sedation was given if needed). The uterine tandem was inserted
easily and correctly with the new cervical sleeve in place. No complications
occurred during or after the procedures.

Conclusions: This simple new technique help uterine tandem insertion without general anesthesia avoiding its hazards (especially in risky patients) andsave time during brachytherapy applications. The new sleeve is as safe andapplicable as Smitt sleeve; however, it is more available and cheaper.
798 poster
ONCE OR TWICE A DAY? TWO SCHEDULES OF RADIOCHEMOTHERAPY IN PATIENTS WITH ADVANCED CERVICALCANCER.
H. Grzbiela1 , K. Raczek-Zwierzycka1
1
MSC M EMORIAL C ANCER C ENTER AND I NSTITUTE OF O NCOLOGY,
G LIWICE B RANCH, III Radiotherapy Clinic, Gliwice, Poland
Purpose: The aim of the study was to evaluate and compare the early toxicity
and efficacy of two different schedules of treatment in patients with advanced
cervical cancer.
Materials: 72 patients, aged 32-69, diagnosed with cervical cancer clinical stage III B (FIGO), histopathologic type squamous cell carcinoma, weretreated with radiotherapy combined with chemotherapy and subsequent
brachytherapy. Only women who completed the treatment and received atleast 9 months of follow-up were analysed.Method: external beam radiation
therapy to the whole pelvis the patients were divided into two groups:o Group
1 37 patients, treated once a day with 2.0-Gy fractions to total dose of 54
Gy;o Group 2 35 patients, treated twice a day with 1.3-Gy fractions (withat least 6 hours interval between fractions) to total dose of 52 Gy; concurrent chemotherapy with cisplatin administered weekly at a dose of 40 mg/m2 ;HDR brachytherapy the patients received a total dose of 30 Gy in uterine
cavity (given to the reference point in 3 fractions) and 48 Gy in upper vagina(in 6 fractions).
Results: All patients received the planned dose of radiotherapy. 18.9% of
patients in group 1 and 25.7% of patients in group 2 didn’t receive the fullplanned dose of chemotherapy due to severe haematological toxicity (grade
3 or 4 on WHO scale).Most patients developed haematological toxicity grade
1 or 2 low leucocyte count in 75.7% of patients in group 1 and in 80% of
patients in group 2; anaemia in 29.7% and 17.1% of patients, respectively;
and low platelet count in 8.1% and 2.9% of patients, respectively. Severe
side-effects (grade 3 or 4 on the EORTC/RTOG scale) concerning lower alimentary tract were observed in 2.7% and 11.4% of patients, respectively.
Severe acute reactions of the urinary bladder were found in 8.1% of patientsin group 1, but the toxicity didn’t exceed grade 2 in group 2.A complete response was achieved by 59.6% of patients in group 1 and 60% of patients ingroup 2.
Conclusions: Both treatment schedules show good therapeutic effects andtoxicity levels were acceptable in both groups. In group 1, anaemia, lowplatelet count and acute bladder reactions were observed more often thanin group 2, whereas severe rectum reactions were more frequent in group 2.
In the second group the total time of treatment was shortened to 26 days (instead of 37 days).Further observation will allow us to evaluate late reactions
and efficacy of the treatment in long-term follow-up.
799 poster
PET SCAN FOR PREDICTING CLINICAL OUTCOME OF PATIENTSWITH RECURRENT CERVICAL CARCINOMA FOLLOWING RADIATION THERAPY
D. N. Sharma1 , G. Rath1 , R. Kumar2 , S. Kumar3 , P. Julka4
1
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, Department of Radiation
Oncology, NewDelhi, India
2
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, Department of Nuclear
Medicine PET , NewDelhi, India
3
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, Department of Gynaecologic
Oncology , NewDelhi, India
4
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, NewDelhi, India
Purpose: To evaluate the role of positron emission tomography (PET) for
predicting the clinical outcome of patients with recurrent cervical carcinoma
following definitive radiation therapy (RT).
Materials: Twenty two patients of post irradiated recurrent cervical carcinoma(PIRCC) were enrolled in this prospective study. 18-fluorodeoxyglucose(FDG) PET imaging was performed in each patient before the salvage therapy. The maximum Standardized Uptake Value (SUVmax) and metabolic
tumor volume (MTV) were measured and correlated with cumulative progression free survival (PFS).
Results: Median age of patients was 42 years. Majority of patients had stage
III disease at the initial presentation and all 22 patients had received priordefinitive RT. The median recurrence free period was 11 months. Salvage
therapy consisted of surgical resection, re-irradiation or palliative chemotherapy depending upon the various clinical and radiological factors. Median SUVmax was 5.8 (range 1.8-50.6) and median MTV was 43 cm3 (range 5.8-243).
The cumulative PFS for all patients was 20% at 30 months. The 1-year PFS
was 28% for patients with SUVmax value of >5.8 versus 42% for those with
SUVmax value of <5.8 (p value 0.01). The 1-year PFS was 43% for patientswith MTV value of >43 cm3 versus 45% for those with MTV value of <43 cm3(p value 0.8).
Conclusions: Our results have suggested that FDG uptake on PET scan can
predict the clinical outcome of PIRCC patients. Further randomized studies
may be conducted with large sample size and longer follow up to establish its
definite predictive value.
800 poster
POST OPERATIVE INTENSITY MODULATION RADIOTHERAPY(IMRT) FOR ENDOMETRIAL CANCER: RESULTS OF THE QUALITY ASSURANCE PROGRAM “DUMMY RUN” OF THE PHASE 2
RTCMIENDOMETRE FRENCH MULTICENTRE TRIAL
I. Barillot12 , K. Peignaux3 , B. Castelain4 , M. Leblanc-Onfroy5 , D.
Williaume6 , C. Haie-Meder7 , D. Lerouge8
1
CHU DE TOURS, Department of Radiation Oncology, Tours, France
2
U NIVERSITÉ F RANCOIS -R ABELAIS, Tours, France
3
C ENTRE G EORGES -F RANÇOIS L ECLERC, Department of Radiotherapy,
Dijon, France
4
C ENTRE O SCAR L AMBRET, Department of Radiotherapy, Lille, France
5
C ENTRE R ENÉ G AUDUCHEAU, Department of Radiotherapy, Saint-Herblain,
France6
C ENTRE E UGÈNE M ARQUIS, Department of Radiotherapy, Rennes Cedex,
France7
I NSTITUT G USTAVE R OUSSY, Department of Radiotherapy, Villejuif, France
8
C ENTRE F RANÇOIS B ACLESSE, Department of Radiotherapy, Caen,
FrancePurpose: The Phase 2 trial RTCMIENDOMETRE was designed to evaluate
the impact of post-operative intensity modulation radiotherapy (IMRT) on thegastrointestinal acute toxicity during treatment of endometrial cancer of stage
I and II. In order to assess the ability of the participating centres to comply
with the protocol guidelines, they were requested to participate in a dummy
run procedure
Materials: CT-data of an eligible endometrial cancer patient were sent to the
7 centres through Equal-Estro platform, including a description of the clinicalcase and a summary of the planification constraints. Each investigator was
requested to delineate: rectum, bladder, small intestine, peritoneal cavity (excluding CTV), femoral heads and the CTV according to RTOG Atlas. Dose
distribution must deliver 45 Gy to 100% of CTV, with the following constraints
to PTV : V40,5 Gy ≥ 95 % and V52 Gy ≤ 5 %). The software Artiview
P2E (Aquilab SAS) was used to compare the contours (kappa test (K)), thedose distribution (from RTdose),to calculate the dose volume histogram andconformity indices (RTOG conformity index (CI), coverage factor (CF), tissue
protection factor (PF); conformity number (CN = PF x CF). In 5 centres thecalculation of the dose distribution has been made using a 3D-IMRT "conventional" technique and with tomotherapy in 2 centres.
Results: According to the mean kappa value of 0.72, the investigators havedemonstrated their capability to conform to protocol requirements regarding
the delineation of the target volume (CTV). However, the qualitative analysis
showed major discrepancies in 4 centres : the first one delineated the entire
vagina instead of the upper third; the second one extended the volume 15 mm
beyond the aortic bifurcation and 2 others did consider a margin of less than
1 cm around the upper third of the vagina. Those centres were requested
to correct their delineation. However, the volume of interest of the vaginalvault did not receive less than 43 Gy in all centres. The delineation of the
bladder and the rectum were highly consistent (K 0.78; K 0,94). Conversely,
small intestine (K 0,49) volume was significantly different from centre to centre
whereas the delineation of the peritoneal cavity was reproducible (K 0,91). All
centres met the compliance criteria for the PTV. V40 Gy in less than 40% of
volume of rectum and bladder was also easily achieved (median dose 35 Gy
and 36 Gy), as well as V40 Gy in less than 300 cc of the peritoneal cavity(median dose 37 Gy). In overall, the dose distribution was good with meanvalues of 1.5, 0.92, 0.70, and 0.63 (ideal values = 1) for CI, CF, PF, and CN,
respectively
Conclusions: Results of this quality assurance program demonstrated thatthe 7 centres were able to comply with the protocol guidelines providing minor
corrections. The use of the RTOG delineation Atlas might have increased theconsistency between centres. The delineation of peritoneal cavity was easierand more reproducible than the delineation of small intestine and was usedin the trial.
801 poster
RADIOTHERAPY PLUS BRACHYTHERAPY IN ELDERLY PATIENTSWITH GYNECOLOGICAL CANCER
C. Chiumento1 , A. Fiorentino1 , A. M. Mileo1 , S. Clemente1 , P. Pedicini2 , G.
Califano1 , V. Fusco2
1
IRCCS/CROB, Department of Radiation Oncology, Rionero in Vulture,
Italy
2
C ENTRO DI R IFERIMENTO O NCOLOGICO DELLA B ASILICATA, Departmentof Radiation Oncology, Rionero in Vulture (PZ), Italy

S 313

Purpose: To examine the acute toxicity profile in elderly patients (pts) withgynecological cancer (GC) receiving adjuvant radiotherapy.
Materials: Patients with age > 65 years old, histological confirm of endometrial cancer and cervical cancer were analyzed in this retrospective study. The
therapeutic approach included Surgery, EBRT (External Beam Radiotherapy)
and BRT (Brachitherapy) (High dose rate HDR, Low dose rate LDR), adjuvant
chemotherapy. Stage was defined according to the FIGO definition. Acutetoxicity was evaluated with RTOG scale.
Results: From August 1999 to December 2009, a total of 50 pts with a median age of 70 years (range 65-83) were treated. Forty-two pts (84%) had
endometrial cancer, only eigth pts (16%) had cervix cancer.FIGO stage was
as follows: 9 pts (18%) IB, 17 pts (34%) IC, 5 pts (7%) IIA, 3 pts (6%) IIB,
10 pts (20%) IIIA, 4 pt (8%) IIIB, 2 pt (4%) IIIC. Forty-seven patients (94%)
underwent radical hysterectomy plus bilateral salpingo-oophorectomy withpelvic lymph node dissection in only 14 pts (30%); 3 pts (6%) did not receive
surgery for medical reasons. All pts were treated by EBRT with a total dose of
45.0-50.4 Gy (180cGy/die).15 pts (30%) received chemotherapy; most given
carboplatin and paclitaxel.BRT was performed in 48 pts (96%) with vaginal
cylindres: 6/48 pts received LDR-BRT, 42/48 HDR-BRT. Only two pts refused
BRT. Compliance to radiotherapy was 100%Acute toxicity was mild. During
irradiation, hematological acute toxicity G1-2 occurred in 13 pts (26%), while
G3 in only 1 pts (2%).Eleven pts (22%) developed rectal acute toxicity G1
and 4 pts (8%) G2; about bladder acute toxicity G1 developed in only 2 pts(4%).During BRT no patients experienced acute toxicity.At a median follow-up
of 60 months (12-136); all pts are alive: 42 pts (84%) without disease and 8
pts (16%) with recurrence.
Conclusions: Older endometrial cancer patients have fewer acute adverse
effect with both EBRT plus BRT treatments. It is necessary to evaluate, inthis setting of patients, the quality of life.
802 poster
ROLE OF ADJUVANT RADIOTHERAPY FOR EARLY ENDOMETRIALCANCER: CLINICAL RESULTS
G. De Pascalis1 , M. A. Montesi1 , V. Graziano2 , D. Musio2 , N. Raffetto2
1
P OLICLINICO U MBERTO I, Radiation Therapy, Roma, Italy
2
P OLICLINICO U MBERTO I, Roma, Italy
Purpose: To evaluate the effects of postoperative radiotherapy for different
stages of early endometrial cancer
Materials: Between January 1995 and march 2004, 69 patients affected byearly stages endometrial cancer we observed at the Department of Radiation Oncology, University "Sapienza", Rome. Patients population aged between 37 and 88 years (median age 63,47 years). Risk factor included: early
menarche, late menopausa, nulliparity, diabetes, obesity and unopposed estrogen therapy. Pathologic classification was endometrioid carcinoma in 51 pt(73,9%), papillary serous carcinoma in 12 pt (17,4%), clear cell carcinoma
in 4 pt (5,8%), uterine sarcomas in 2 pt (2,9%). The stage classification(FIGO) was IB G2 21 pt (30%), IB G3 7 pt (10%), IC G1 14 pt (20%), IC
G2 27 pt (40%). All women underwent hysterectomy and bilateral salpingooophorectomy. Lymphovascular invasion (LVSI) was present in 45 pt (65%).
37 pt (54%) were treated with EBRT and 32 pt (46%) with EBRT+ VBT boost.
In EBRT the target volume consisted of the previous site of the uterus andadnexa, the parametria, the proximal two-thirds of the vagina, and the lymphatics along the iliac vessels up to the promontory; the total dose delivered
to this volume was 50-50,4 Gy in 25-28 fractions (2-1,8 Gy/die). Adjuvant
vaginal brachyterapy (192 Ir), pulsed BT or LDR, was delivered with a vaginal
cylinder using 5 Gy weekly fraction for three weeks (total dose 15 Gy in 24-48
h).
Results: In the EBRT group the overall 5-years survival was 81% (30 pt)
and disease free survival was 84%. In the EBRT+VBT group overall 5-years
survival was 85% (27 pt) and disease free survival was 88%. In the EBRT
group locoregional relapse were observed in 405 of patients almost locatedin the vaginal vault. No distant metastases were found in both group. Treatment was well tolerated: most of the acute complications were of grade 1(78%)(RTOG) of the gastrointestinal tract and during the follow-up we did notregister late side effects.
Conclusions: The role of adjuvant radiation therapy in early endometrial cancer is no well longer clearly defined. Our results agreed with data from literature of the stage-1 endometrial carcinoma treated with surgery and postoperative radiotherapy tailored to prognostic factor. Postoperative radiotherapy
in stage-1 endometrial cancer seems to reduce locoregional recurrence but
has no impact on overall survival.
803 poster
SETUP ERRORS USING PORTAL IMAGING IN PATIENTS WITHGYNECOLOGICAL CANCERS BY TWO METHODS OF ALIGNMENT
S. Singh1 , A. Singh1 , K. J. M. DAS1 , H. SINGH1 , S. Kumar1
1
S ANJAY G ANDHI P OSTGRADUATE I NSTITUTE OF M EDICAL S CIENCES,
Department of Radiotherapy, Lucknow UP, India

Purpose: Alignment tattoos on a lax abdomen contribute to misalignmentS 314of patients undergoing abdomino-pelvic radiotherapy (RT). Therefore, setup
reproducibility during RT using portal images in patients with gynecologicalcancers positioned identically but aligned to the machine isocentre by two
different ways was undertaken.
Materials: A prospective study in 35 women treated with RT for uterine or
cervical cancer using conformal techniques was undertaken. Following a RT
planning scan in the supine position using an ankle positioning device, 3 reference points were tattooed (reference plane) - anteriorly at the symphysis
pubis (mons pubis) and one on each side laterally at a fixed table top-tovertical height of 10cm, while a fourth point was tattooed at the xiphoid in theanterior midline. A 4-field box plan was generated with beams-eye-view fittingof the planning target volume by multi-leaf-collimators. Patients were alternatively assigned to a conventional method of set up- Arm I (n=18), where a newsetup isocentre was defined by a cranial offset to the reference plane or Arm
II (n=17) where the patient was aligned to the reference plane and moved afixed distance of 4cm cranially for daily treatment. Anterior and right lateral
digitally reconstructed radiograph setup fields of 20x20cm2 were created at
the treatment isocenters and compared with orthogonal MV portal images(PI) taken during initial 3 days of RT and subsequently twice weekly. Setup
deviations - rotations and translations were analysed in medio-lateral (ML),cranio-caudal (CC) and antero-posterior (AP) direction. No online/offline corrections were performed. The set up time to position patients and their weight
were recorded on the days of PI. Population systematic and random errors
were calculated and planning target volume (PTV) margins required were estimated using the formula of van Herk.
Results: Arm I had 209 PI while Arm II had 188 PI. Patients in both the arms
has similar body weight (mean ± SD; 58.2Kg±11.7 vs. 56.6Kg±11.2) andsetup time (240sec±61 and 250sec±59) respectively. From the anterior portal images systematic errors (SE) in ML, CC direction and yaw were 0.50cm,
0.37cm, 0.91◦ and 0.28cm, 0.27cm, 1.07◦ respectively while the random
errors (RE) were 0.48cm, 0.35cm, 0.79◦ and 0.34cm, 0.59cm, 1.05◦ respectively. Similarly for the lateral portal images SE in CC, AP direction and pitch
were 0.32cm, 0.20cm, 2.30◦ and 0.25cm, 0.20cm, 1.90◦ respectively while
the RE were 0.31cm, 0.24cm, 2.26◦ and 0.57cm, 0.25cm, 1.92◦ respectively.
It was observed that Arm II had a lesser SE in the ML direction and major deviations (>5mm) in ML were recorded in 28% in Arm II vs. 47% in Arm I. The
corresponding PTV margin in the ML direction calculates as 1.6cm vs. 0.9cm
in Arm I and II respectively. SE in AP direction was least (0.20cm) in both thegroups.
Conclusions: The setup arm (II) had a better reproducibility without an increase in setup time suggesting that locating the anterior tattoo at the relatively immobile portion of lower abdomen (mons pubis) is superior to a morecranial location over the flabby abdomen
804 poster
SMALL CELL CANCER OF GYNAECOLOGY ORIGIN: MANAGEMENT
AND RESULTS
N. G. Charnley1 , A. hindley1 , G. skailes1 , M. Hogg1
1

H EAD N ECK CANCERG YNECOLOGICAL CANCERR OYAL P RESTON H OSPITAL, Oncology , Preston, United Kingdom

Purpose: To assess management and outcomes of patients treated for small
cell cancer (SCC) of gynaecological origin from 2000-2010
Materials: 4 patients with SCC of the cervix and 2 patients with SCC of thevagina were treated between 2000 and 2010. All patients had radiotherapy
to the pelvis with neoadjuvant chemotherapy and 5 had concurrent platinum
based chemotherapy. Survival was calculated from the start of chemotherapy.
Results: Median age of patients was 46. One patient had NIDDM. No othercomorbidity was identified. Two patients were within six months post partum
when diagnosed.Three patient were stage 1, 2 stage 2 and 1 stage 3. Twopatients were node positive. One patient had radical hysterectomy prior to radiotherapy. Three patients received 45 Gy in 20# to the pelvis, 3 had 40 Gy/20#, and 1 patient had an additional boost of 20 Gy/10#. One patient had paraaortic nodes treated. Three patients had prophylactic cranial irradiation (PCI)
following chemoradiotherapy, 25Gy/10#. No patients had brachytherapy.Five
patients had weekly cisplatin during radiotherapy. Four patients had 2 cyclesof etoposide cisplatin prior to and following radiotherapy. One patient had
2 cycles of carboplatin etoposide alone pre radiotherapy. One patient had
6 cycles of adriamycin, cyclophosphomide etoposide pre radiotherapy. All
patients completed their treatment. One patient had grade 3 haematologial
toxicity which led to a deferral in chemotherapy. One patient had neutropenic
sepsis.All patients had an initial response to chemoradiotherapy. One patientwith vaginal cancer had persistent disease on completion of treatment. One
patient who did not have PCI developed brain metastases 5 months after
completing treatment, and one patient developed in field local recurrence 9months after treatment. Both these patients have died.At last follow up, 4/6
patients were alive, 3/4 were free from disease. In this small group of patients,
median survival was 2.3 years.
Conclusions: A reasonable outcome is achievable following chemoradiotherapy for SCC of gynaecological origin. This is better than would be expected for SCC of lung origin. Data suggests we should explore the role of
PCI in these patients.

805 poster
THE MANAGEMENT OF PATIENTS WITH UTERINE SARCOMA: A
RETROSPECTIVE ANALYSIS OF 41 PATIENTS.
S. Pandit1 , A. K. Gandhi1 , D. Sharma1 , S. Jain2 , P. Julka1 , G. Rath1
1
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, Department of Radiation
Oncology, NewDelhi, India
2
A LL I NDIA I NSTITUTE OF M EDICAL S CIENCES, Department of Gynaecology
and Obstetrics, NewDelhi, India
Purpose: To evaluate the treatment outcome and survival data in patientswith uterine sarcoma
Materials: Medical records of 41 patients of uterine sarcoma treated in gynecological oncology clinic from 2000 to 2010 were reviewed. Mean age was49.3 years (range 25-75 years). There were 19 had carcinosarcomas, 13
leiomyosarcomas, and 9 endometrial stromal sarcoma.
Results: Seventeen patients had underwent TAH+BSO and pelvic lymphadenectomy, 17 underwent had underwent TAH+BSO, 4 underwent TAH,
2 underwent tumor debulking while 1 patient did not undergo surgery. Altogether 24 patients received adjuvant radiotherapy (dose: 45-50.40Gy), and3 patients received palliative radiotherapy. Among the patients who received
adjuvant radiotherapy, 14 received HDR-brachytherapy (intracavitary in 9 andinterstitial in 1) while 10 patients did not receive brachytherapy treatment. Altogether 13 patients received adjuvant chemotherapy (range3-6 cycles). Survival analysis included 32 patients who had follow up of at least 1 month. Outof these patients 21 had no evidence of disease and 13 had progressive disease in last follow up. Median progression free survival (PFS) of whole groupwas 31.4 months. Univariate analysis revealed that adjuvant radiotherapy
was associated with significantly better PFS (11 months Vs. 49.2 months,
p=.011, log rank test), while chemotherapy (p = 0.71), histology (p = 0.26)
and patient age (p = 0.45) did not have significant effect on PFS.
Conclusions: Uterine sarcoma is a heterogeneous group of rare tumors thatusually have a poor prognosis. Multimodality treatment with surgery and adjuvant radiotherapy and chemotherapy is the treatment of choice. Adjuvant
radiotherapy using external beam radiation and brachytherapy significantly
improves survival of these patients.
806 poster
TOXICITY AND RESULTS OF WHOLE ABDOMINAL PELVIC RADIOTHERAPY (WAPR) WITH OR WITHOUT CHEMOTHERAPY IN
ADVANCED ENDOMETRIAL CANCER
M. A. Cascales1
1
H OSPITAL 12 DE O CTUBRE, Radiation Oncology, Madrid, Spain
Purpose: Advanced serosus-papilaris or extrauterine-disease of endometrial
cancer, behave like ovarian serosus cancer. A well-made optimal surgery,must be the most important objective in order to get the best global outcome.
Adyuvant treatment could be whether chemo-radiotherapy on the primary siteof the tumor localization whether WAPR with or without chemotherapy. The
purpose of this review is to analyze our experience about the treatment andthe outcome of patients with advanced endometrial cancer or serosus papilaris cancer of the uterus treated with WAPR, associated with or without
chemotherapy.
Materials: Between 2001 and 2010 we have treated 34 women with advanced endometrial cancer or serosus-papilaris endometrial cancer. All ofthem received the WAPR technique; 8 of them received WAPR like theonly adyuvant treatment and in 26 of them, WAPR was administrated after
chemotherapy. Mean disease free survival (DFS) was 30,7 months (r: 2-112).
Mean patients’ age was 60 years (r: 45-76). Only 20 patients received an optimal surgery (an ovarian surgery-like). Residual disease was not found in 27
patients, 2 patients had a residual disease of less than 1 cm and 6 women
had a residual disease of more than 1 cm. There was no node resection in 7
patients, negative nodes were found in 7 patients (pN-) and 20 patients had
positive nodes (pN+), whether in pelvic or para-aortic site. Pure endometrial
histology was found in 28 patients, while 6 patients had synchronic endometrial and ovarian cancer. Post-surgery FIGO stage was IIIA in 8 patients, IIIBin 1 patient, IIIC in 16 and IVB in 9. Pathologic histology was endometrioid in
15 patients, serosus-papilaris/clear cell in 16 and 3 patients Mullerians. The
histologic grade was G1-G2 in 10 patients while G3 was in 24. Chemotherapy was carboplatine-taxol x 6 in 21 patients, and cisplatine-adriamicine in 5.
Patients treated only with WAPR (as the only adyuvant therapy) received 30
Gy in abdominal field (fractionated at 5 x 150 cGy) and pelvic+/- paraaortic
field (15-50 Gy, at 5 x 180 cGy or 5 x 200 cGy). Patients treated with Chemoradiotherapy received 22,5 Gy in the abdominal field (at 5 x 150 cGy) anda pelvic +/- paraaortic field of 23,4-24 Gy (at 5 x 180 cGy or 5 x 200 cGy).
Afterwards, 29 patients received vaginal brachitherapy wheter LDR whether
HDR.
Results: Patients treated with chemo-radiotherapy (QT-WAPR) have tolerated treatment as well as those ones who received only WAPR. Though initial hemoglobin, leucocite, neutrophyle and platelet count levels were lower(p < 0,001) in the first group, their decrease was significantly lower than in
the second group. Only one patient had a gastrointestinal acute G3 toxicity (diarrhea). There was no bowel obstruction for the surveillance period.

There were 11 relapses (8 of them abdominal, 1 inguinal metastase and 2
mixtes; metastases and abdominal relapses). 6 of these patients have deaddue to their disease. Actuarial DFS at 3 and 5 years was 60% and 53% respectively. Univariant analysis shows a lower DFS in histologic grade G3 (p=0.046), with a residual disease bigger than 1 cm (p 0,01) or having more than
3 extrauterine sites (p = 0,003)
Conclusions: WAPR is a feasible and sure adyuvant therapy, with or without
the association of chemotherapy. It has an acceptable toxicity. Prognostic
factors significant in DFS have been Histologic grade G3, residual disease
and the number of extrauterine sites (>3)
807 poster
VOLUMETRIC MODULATED ARC THERAPY WITH RAPIDARC(RA-IMRT) FOR GYNAECOLOGICAL MALIGNANCIES
R. Lazzari1 , A. Cecconi1 , V. Dell’Acqua12 , A. Vavassori1 , E. Rondi3 , S.
Vigorito3 , F. Cattani3 , C. Fodor1 , B. A. Jereczek-Fossa12 , R. Orecchia12
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Radiotherapy, Milan,
Italy
2
U NIVERSITY OF M ILAN, Milan, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Medical Physics, Milan,
Italy
Purpose: To evaluate the impact of a novel image-guided radiotherapy technique with volumetric intensity modulated arc therapy -RapidArc (RA-IMRT)
in gynaecological cancer in terms of genito-urinary (GU) and gastro-intestinal(GI ) acute toxicity and clinical outcome.
Materials: From February to November 2010, 32 patients (pts) affected bygynaecological malignancies were treated with RA-IMRT. Seven received radical therapy for unresectable cervix carcinoma, 13/32 - post-operative therapy
for cervix carcinoma, 1/32 reirradiation for the recurrent vaginal carcinoma,
3/32 post-operative therapy for endometrial carcinoma, 2/32 post-operative
therapy for vulvar carcinoma, 3/32 radical therapy for cuff recurrence of endometrial carcinoma, 2/32 radical therapy for pelvic recurrence of cervical carcinoma and 1/32 palliative treatment for para-bone pelvic metastases of vaginal carcinoma.In 18/32 patients concomitant chemotherapy was added to RAIMRT (agents: CDDP or CDDP plus Paclitaxel).For treatment planning the CT
scan was integrated with CT/FDG-PET and/or MRI for gross tumour volume(GTV) delineation. Simultaneous integrated boost (SIB) technique was employed: 45-56 Gy (1.8 Gy/fraction) was prescribed to the T or surgical T bed,
45-50.4 Gy (1.8 Gy/fraction) to N0 pelvic and/or para-aortic lymph nodes and55 Gy (2.2 Gy/fraction) to the positive lymph nodes.For 18 pts the radiation
treatment schedule included also a boost of 15-30 Gy to be delivered withhigh or pulsated dose rate brachytherapy (HDR or PDR).Radiation Therapy
Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria were used for the acute toxicity classification.
Results: Maximum acute toxicity registered during radiotherapy treatment
was: cutaneous toxicity: G0=29pts, G1=3pts, GU toxicity: G0=20pts, G1=9pts, G2=3 pts and GI toxicity : G0=10 pts, G1=16 pts, G2=6 pts. The last
day of radiotherapy-treatment the majority of acute events were resolved: thecutaneous, GU and GI toxicity as follows: G0=30 pts ,G1=2 pts ;G0=25 pts,
G1=6 pts;G0=18 pts,G1=13 pts, G2=1 pts respectively.One month after treatment 21/32 pts are evaluable and the skin, GU and GI toxicity was G0 for all
pts but one (GU toxicity G1). After a mean follow-up of 2 months (range 1-7
months) 21/32 pts are evaluable: 18/21 pts are in complete remission, 1/21
is not evaluable and 2/21 experienced progressive disease in other site.Only
6/32 pts are evaluable after 3 months of follow-up and the toxicity was G0.
Conclusions: Our preliminary experience showed that RA-IMRT is a highly
tolerable technique with low skin, GU and GI toxicity. Further investigation
with higher patient number and longer follow-up is warranted in order to verify
if low acute toxicity observed in our preliminary analysis is translated to low
late toxicity and satisfactory tumour control.

S 315

Head Neck cancer
808 poster
18F- FLUOROAZOMYCIN ARABINOSIDE (FAZA) PET IN PATIENTSWITH HEAD AND NECK SQUAMOUS CELL CARCINOMA (HNSCC)
L. S. Mortensen1 , M. Busk1 , M. Nordsmark1 , J. Johansen2 , J. Theil3 , J.
Overgaard1
1
A ARHUS U NIVERSITY H OSPITAL, Department of Experimental ClinicalOncology, Aarhus C, Denmark
2
O DENSE U NIVERSITY H OSPITAL, Department of Oncology, Odense,
Denmark
3
A ARHUS U NIVERSITY H OSPITAL, PET center, Aarhus C, Denmark
Purpose: Tumor hypoxia induces resistance to therapy, and is associatedwith poor local control and survival. The purpose of this clinical study was
to investigate baseline hypoxia in patients with head and neck squamous cell
carcinoma (HNSCC) using 18 F- fluoroazomycin arabinoside (FAZA) PET prior
to and during the radiation therapy.
Materials: A total of 40 patients with HNSCC requiring primary radiotherapy therapy were to be included in the study. A pretherapy PET/CT scan
was performed 2 hours following administration of approximately 350 MBq
FAZA. Some patients had a second scan 1-2 weeks following the start of theirtreatment. The patients received radiotherapy according to the DAHANCA
guidelines. FAZA-uptake was quantified by calculating standard uptake values (SUV), tumor-muscle-ratios (T/M) and expressed as percentages of injected dose. For each tumor individual histograms of T/M will be presented.
For patients with 2 scans, the two histograms will be compared.
Results: To date pre-treatment measurements have been performed on 17
HNSCC patients (T2-T4 N0-N3 M0). Of these patients, 9 had a second scan
1-2 weeks following the start of treatment. Preliminary results show the PET
scans to demonstrate variable uptake of FAZA at baseline in the primary tumor as well as the lymph nodes. For the patients who received a second
scan only some of the patients had uptake of FAZA.An example of two scansof a 50 year old woman with T3 N2 M0 cancer of the oropharynx is seen in
figure 1. The baseline scan shows uptake of FAZA within the tumor. A week
after start of treatment ( 66 Gy/34 fractions with concomitant Cisplatin andNimorazol) there is still high uptake of FAZA within the tumor.
Conclusions: Multiple scans are possible. Additional patients are being
included and the PET measurements will later be correlated to outcome interms of loco regional control and survival.

809 poster
2D PORTAL DOSIMETRY FOR A SMALL ANIMAL IRRADIATOR
P. Granton12 , S. van Hoof3 , M. Podesta42 , S. Nijsten52 , W. van Elmpt52 , F.
Verhaegen2
1
MAASTRO C LINIC, Department for Radiotherapy and Oncology, Maastricht, Netherlands
2
M AASTRICHT R ADIATION T HERAPY AND O NCOLOGY (MAASTRO) CLINIC,
Department of Radiation Oncology, Maastricht, Netherlands
3
T ECHNICAL U NIVERSITY E INDHOVEN, Department of Medical Biophysics,
Eindhoven, Netherlands
4
M AASTRICHT R ADIATION O NCOLOGY (MAASTRO CLINIC ), Department ofRadiation Oncology, Maastricht, Netherlands
5
MAASTRO CLINIC, Department of Radiation Oncology, Maastricht,
Netherlands
Purpose: New image-guided small animal micro-irradiators (micro-IR) arebecoming available for pre-clinical research. However, modern treatment
planning software platforms are not easily adapted to small animal microIR devices due to the beam sizes (down to 1 mm) and beam energies (0-300kVp), making complex dose calculations challenging. To ensure that differences between planned dose and delivered dose distributions are reasonably
small, the goal of this study was to develop a dosimetric calibration model fora small animal irradiator using the on-board flat panel detector. This is a firststep towards a reconstruction model to establish 3D delivered dose.

S 316

H EAD N ECK CANCER

H EAD N ECK CANCER

Materials: The dose deposition at the isocenter of a small animal micro-IR(225Cx, PXI Inc., CT, USA) was characterized using radiochromic film andcompared to images from the on-board 1024 x 1024 CsI flat panel amorphoussilicon detector. A dosimetric calibration model was developed to include again/field, beam blur kernel, and image lag correction for an irradiation energyof 225 kVp, 5 mA, 0.32 mm Cu at the isocenter.To determine the accuracy ofthe dosimetric calibration model, three fixed beam sizes (5, 10 and 18 mm indiameter) were delivered for 24, 36, and 30 seconds (approximately 2 Gy total
dose) to radiochromic film at the isocenter of the micro-IR and compared to ameasured portal dose image (in-field) using a gamma calculation with gamma
criteria of 5% and 5 mm.
Results: A comparison between the measured portal dose image and radiochromic film resulted in 83 % of the pixel values <1. The field was foundto vary less than 0.1 % over the region-of-interest at the detector. Therefore,a homogeneous field was assumed for the gain/field correction since highfrequency errors in the film (i.e. dust) were found to detract from the correct
gain/field correction. The beam blur kernel was determined iteratively for thesmallest sized beam as a 15 x 15 pixel Gaussian function with a standard
deviation of 7 pixels. The image lag was characterized using the trailing edge
response function that was found to reach a maximum residual signal of 2.5% following 120 frames of radiation reaching saturation. An image lag correction kernel was determined iteratively as an exponential decay function(Signal(frame iN) = 0.005*exp(-0.4(frame iN-1)) for a 10 frame window.

the smallest beam. Selective beam blur kernels for each size beam should
improve our dosimetric calibration model.
810 poster
2D/3D COMPARISONS OF IG-IMRT VERIFICATIONS FOR NASOPHARYNGEAL CARCINOMA IN THE SOUTHERN PHILIPPINES
N. Arriola1 , E. Tangco1 , G. Banuelos1 , M. Cruz1 , M. Olvina1 , T. Sarmiento1 ,C. R. Aguilar1 , C. Devilleres1
1
S T. F RANCES C ABRINI M EDICAL C ENTER, Department of Radiation
Oncology, Batangas, Philippines
Purpose: This is a prospective study of all patients diagnosed with nasopharyngeal carcinoma (NPCA) from the period of 2008 to 2010 who underwent
Image Guided-Intensity Modulated Radiation Therapy (IG-IMRT). All patientswere treated using IMRT technique combined with anterior split neck using
ELEKTA Synergy linear accelerator. This is to report a single institutional experience with the promising technology that would enhance and develop astandard protocol for Filipino patients diagnosed with NPCA in St. FrancesCabrini Medical Center and compare their treatment accuracy using 2D imaging via electronic portal imaging device (EPID) and 3D x-ray volumetric image(XVI) guidance RT.
Materials: The dawn of volumetric image-guidance for the delineation of targets and anatomical skeletal structures assists in the beginning of the 3D
verification of treatments from volume-reconstructed Computed tomography(CT) images. Positioning and verification prior to treatment played a major role in the correct and precise implementation. The 3-millimeter CT-plan
images of the patient were acquired using Philips Brilliance 6 CT scannerwith thermoplastic mask immobilization. All necessary contours were identified by the attending radiation oncologist in every slice. The equally spaced
fivetwelve coplanar field IMRT plans were centered on the gross tumor volume (GTV) via forward planning using Precise planning system. The treatment encompasses the lymph nodes through the clinical target volume (CTV)
and at least 0.5cm margin for the planning target volume (PTV). Verificationof positioning was done through IviewGT EPID and XVI Cone Beam CT (XVI
CBCT) module. Necessary corrections were incorporated in the plan through
EPID correction and volumetric-check through the XVI CBCT and vice versa.
Inter-treatment motion quantification was accomplished through EPID and
XVI CBCT after treatment.
Results: A total of 9 NPCA patients were included in this study. Comparisonof the positioning displacement showed that positioning with IGRT showed
an increase in accuracy compared to the positioning done with EPID. Intertreatment positioning discrepancy was found to be minimal.
Conclusions: IMRT combined with IGRT allows visualization and optimalcorrection to ensure that treatments were as accurate as possible. This study
represents most of the patients treated with IG-IMRT using the XVI CBCT 3D
VolumeView radiation image in combination with 2D IviewGT EPID verification techniques. The study demonstrated an integration of advance technologies for immobilization, 3D volume imaging for target localization with correction, and quality assurance for the accuracy of the treatments. This study also
showed the feasibility of IG-IMRT on a daily basis for the institution’s patients
undergoing radiation therapy.
811 poster
64CU-ATSM PET/CT AND 18F-FDG-PET/CT IN THE STAGING ANDTARGET VOLUME DELINEATION FOR HEAD AND NECK CANCER(H&N).
A. Cecconi1 2 , C. Nanni3 , F. Bunkheila4 , I. Grassi3 , A. Guido4 , S. Fanti31 ,E. Barbieri4 1
1
U NIVERSITY OF B OLOGNA, Bologna, Italy
2
E UROPEAN I NSTITUTE OF O NCOLOGY, Milan, Italy
3
P OLICLINICO S. O RSOLA M ALPIGHI, Division of Nuclear Medicine,
Bologna, Italy
4
P OLICLINICO S. O RSOLA M ALPIGHI, Division of Radiotherapy, Bologna,
Italy

Conclusions: This report represents work towards a 2-D, and ultimately 3D, in vivo portal dose model for a small micro-IR. The portal dose correction
model developed here fell within a 5 % 5 mm criterion with the deviations
largely found around the perimeter of the two largest beams. These inaccuracies are likely due to the beam blur kernel which was determined only for

Purpose: To highlight hypoxic areas within the primary tumour and/or lymph
nodal metastasis with 64Cu-ATSM PET/CT and to correlate its uptake withthe event free survival after Intensity modulated radiation therapy (IMRT)
in pts affected by H&N cancer. Secondary aim is to compare 64Cu-ATSM
PET/CT to FDG-PET/CT which is routinely used in our institution to draw thetarget volume.
Materials: From September 2009 to December 2010, 7 pts with H&N cancer
have been enrolled ,median age was 57 years (range 45-82 years) . All pts
underwent an 18f-FDG-PET/CT (carried out with standard technique) before
therapy to stage the disease and for target volume delineation (gross tumour
volume : GTV). Within 2 wks, they underwent also a 64Cu-atsm pet/ct tohighlight the hypoxic areas in the neoplastic lesions. 185 to 555 MBq of 64CuATSM were injected iv. Images were acquired after 2h (early acquisition)and 16h (late acquisition) on a dedicated scanner (GE, Discovery STE) to
eventually observe a tracer re-distribution. SUV max was calculated both for
FDG and ATSM. After this diagnostic flow chart, the pts were treated with

IMRT on the basis of FDG-PET/CT.
Results: All the pts presented and increased uptake of FDG and ATSM,
showing highly proliferative and hypoxic tumours. The following table shows
the results of imaging procedures.64Cu ATSM presented a biodistribution
equivalent or inferior to FDG and the SUV max tended to increase in lateacquisitions. After a median follow-up of 10 months (range 1-15 months) 4
pts are in complete remission, 1 pt died after 1 month for persistence of disease and 2 pts currently undergoing to radiotherapy treatment.

S 317

to the PTVs. Due to left-sided visual loss, maximum priority was placed onachieving dose constraints of <50Gy to the right optic nerve (RON) and optic chiasm (OC). Standard dose constraints were used for the other OARs.
The fixed gantry IMRT plan was optimised using seven coplanar fields. The
3DCRT plan used an anterior and parallel opposed lateral fields to the primary tumour and matched anterior fields to the neck. The RA plan was
optimised using two 360o coplanar arcs in clock- and counterclock-wise directions. Quantitative analysis of the plans was performed using DVHs. PTV
conformity and homogeneity, MU and delivery time were assessed.
Results: Dosimetric results from DVH analysis of the plans are shown in
Table 1. PTV coverage was better in the IMRT and RA plans compared to the
3DCRT plan but not significantly different between the IMRT and RA plan.
PTV1 coverage was compromised in all the plans due to the close proximitywith the RON and OC. PTV1 maximum doses (D2%) were 108%, 105% and106% of the prescription dose in the 3DCRT, IMRT and RA plans respectively.
PTV1 minimum doses (D95%) were 68%, 92% and 90% of the prescription
dose in the 3DCRT, IMRT and RA plans respectively. PTV conformity andhomogeneity was similar between the IMRT and RA plans. All plans achieved
the dose constraints to the RON and OC. Spinal cord maximum doses werelower in the RA plan while brainstem maximum doses were slightly lower
in the IMRT plan. Parotid gland sparing was not achieved due to the small
volume of the glands. The RA plan required fewer MU (48% less) and shorter
delivery time (reduced by a factor of 5) compared to the IMRT plan.

Conclusions: 64Cu ATSM PET/CT did not change the radiotherapy plan. A
wider population of pts (especially with negative ATSM PET/CT) is needed tounderstand whether ATSM uptake is a prognostic factor or not, and to clarify
if adding a boost of dose in ATSM positive areas may change pts prognosis.
812 poster
A COMPARISON OF RADIOTHERAPY PLANNING TECHNIQUESFOR A COMPLEX CASE OF SINONASAL UNDIFFERENTIATED
CARCINOMA
M. Teoh1 , D. Rickard2 , S. Sandle3 , G. Distefano2 , C. Clark4 , K. Wood5 , S.
Whitaker6 , A. Nisbet7
1
R OYAL S URREY C OUNTY H OSPITAL, Clinical Oncology, Guildford, United
Kingdom
2
R OYAL S URREY C OUNTY H OSPITAL, Medical Physics, Guildford, United
Kingdom
3
R OYAL S URREY C OUNTY H OSPITAL, Radiotherapy Department, Guildford,
United Kingdom
4
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, Medical
Physics, Guildford, United Kingdom
5
T HE R OYAL S URREY C OUNTY H OSPITAL, Clinical Oncology, Guildford,
United Kingdom
6
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, ClinicalOncology, Guildford, United Kingdom
7
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, Guildford,
United Kingdom
Purpose: Sinonasal undifferentiated carcinoma (SNUC) is a rare malignancy
arising in the paranasal sinuses and commonly presents at an advanced
stage with poor prognosis. The recommended treatment for operable disease is surgical resection and post-operative radiotherapy. We present thecase of a 66 year old patient with an extensive locally advanced SNUC arising in the nasal cavity, invading the anterior skull base and left optic nerve.
She was treated with radical chemoradiotherapy using IMRT. The aim of thisstudy is to perform a retrospective planning comparison between the fixed
gantry IMRT plan, a conventional 3D conformal radiotherapy (3DCRT) plan
and a volumetric modulated arc therapy (RapidArc (RA)) plan to evaluate theoptimal treatment plan for this complex case.
Materials: The same planning CT dataset was used in all the plans. The
dose prescription to the primary PTV (PTV1) was 65Gy in 2.17Gy/fractions
and 54Gy in 1.8Gy/fractions to the elective PTV (PTV2). The planning objectives were to achieve maximum dose <107% and minimum dose >95%

Conclusions: IMRT and RA techniques achieved comparable treatment
plans which were superior to the 3DCRT plan in this case. Both techniquesshould be considered for such technically complex planning cases. RA has
the additional benefit of reduced MU and delivery time.
813 poster
A RANDOMISED STUDY COMPARING TWO IMMOBILISATION
DEVICES FOR PATIENTS RECEIVING RADIOTHERAPY FOR HEAD
AND NECK CANCER (H & N) VIA CONE-BEAM CT.
K. Woods1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Department Of Oncology Radiotherapy Unit, Bebington, Merseyside, United Kingdom
Purpose: Two forms of immobilistion , clear plastic shells and a commercial
thermoplastic material were compared for immobilisation , cost and radiationskin reaction .Both types of immobilisation device locate onto a carbon fibreand individual T-shaped vacuum bags were used as headrests.
Materials: 30 patients with oropharyngeal cancer were planned using thetreatment planning system and treated using intensity modulated radiotherapy (IMRT) on a Varian linear accelerator with cone beam computerised tomography (CBCT) facility. All patients had CBCT’s at fractions 1-3 and thenweekly once the systematic errors had been identified and the random errors
were within departmental tolerances. The CBCT’s were registered with reference scan on line at the superior, centre and inferior levels of the PTV. The
results from the match of reference scan with CBCT were used to compare
the interfraction displacement for both types of immobilisation mask. Theinterfraction displacements were separated into systematic (Σ) and random
errors(σ ). For each patient, the average displacement (Mp) and the standard
deviation (SDp) of all the displacements over all fractions were calculated.
The systematic error was calculated from the standard deviation of Mp of all
patients for both types of immobilisation mask; the random error was calculated as the root-mean-square over all SDp.

S 318H EAD N ECK CANCER

H EAD N ECK CANCER

the study will be compared to previous research in the area and it is hoped toformulate a list of products and methods used to overcome oral problems byparticipants in the Irish setting.
Conclusions: Recruitment for this study will finish in April 2011 and results
will be analysed and compared to previous research in the area.

Results:
Conclusions: The study showed that Thermoplastic and clear plastic shells
produced similar patient immobilisation , equivalent in cost , however , theclear plastic shells produced more severe skin reactions.
814 poster
ACCELERATED FRACTIONATION FOR EARLY GLOTTIC CARCINOMA – SINGLE INSTITUTE EXPERIENCE
A. S. Sudha1 , R. Kumar1 , C. Kainickal1 , N. Bhuvanendran1 , R.
Kunnambath1
1
R EGIONAL C ANCER C ENTER, Department of Radiotherapy, Trivandrum,
India
Purpose: To report the outcomes of definitive accelerated radiotherapy (RT)for early stage squamous cell carcinoma (SCC) of the glottic larynx.
Materials: Retrospective analysis of 275 patients with T1-T2 N0 squamouscell carcinoma of the glottis treated between 2003 and 2008. All patients weretreated with an accelerated radiotherapy schedule of 52.5Gy /15fr (3.5Gy/fr)
over 3 weeks.
Results: The median follow-up is 46 months. The 5 year disease free survival
rates were : T1a,94 %; T1b,94.5%; T2,89.9% and overall 93.4%. Seventeen(6.2%) patients relapsed either locally or in the neck, of which 11 patientswere salvaged successfully by surgery with an ultimate local control of 96% at
5 years. In univariate analysis, involvement of the subglottis was the only factor found to influence the local control and overall survival. Eighteen patients( 6.5%) had loss of laryngeal function due to laryngectomy (8 patients) or tracheostomy (10 patients). Three (1.1%) patients developed chondronecrosis
which required laryngectomy and10 (3.6%) patients had dyspnoea due to laryngeal edema which required tracheostomy. The 5 year survival rates withlaryngeal function preservation are T1a, 94.5%; T1b, 85.7%; T2, 79.7% andoverall 90%. Tumour stage and subglottis involvement were found to significantly influence the laryngeal function preservation rates.
Conclusions: Accelerated radiotherapy has excellent cure rates in T1-T2 N0glottic SCC and has very low rates of severe late complications.
815 poster
ADVANCED RADIATION THERAPY PLAN FOR GLM BASED ON
FMRI
J. Berberat1 , S. Rogers1 , S. Khan1 , A. Meister1 , S. Bodis1 , L. Remonda2 ,G. Lutters1
1
K ANTONSSPITAL A ARAU, Radiation Oncology, Aarau, Switzerland
2
K ANTONSSPITAL A ARAU, Neuroradiology, Aarau, Switzerland
Purpose: Following radical radiotherapy (RT), high grade gliomas such as
glioblastoma multiforme (GBM) frequently recur within the high dose volume
and it is plausible that conventional planning margins might be reduced without a loss of local tumour control. Akin to the current evaluation of reduction in
the dose delivered to the hippocampal and limbic systems to reduce radiationrelated memory impairment, other uninvolved critical functional cerebral areas should be spared to minimise the potential acute and late toxicities ofradiation therapy. The aim of this study was to explore the impact of speech
centre localisation using functional MRI (fMRI) on the RT planning process in
GBM.
Materials: Language function was activated in a 68-year old male with aright fronto-parietal GBM using a ’word generation’ task. Block designed
blood oxygenation level dependent (BOLD) fMRI was applied (1.5 T Siemens
Avanto scanner) during lingual stimulation [1]. BOLD-clusters were assessedindividually for anatomical localization. fMRI was performed using EPI sequence and T1-weighted anatomical 3D VIBE sequence was used for functional image analysis and overlay [1]. The functional image analysis andoverlay procedures were performed using BrainVoyager (BrainInnovationBV,
Maastricht, The Netherlands). A CT scan (Siemens Open Sensation) was
performed to delineate the radiation target volume and organs at risk (OAR)(Fig 1A). The fusion of the 3-D anatomical and functional datasets (CT+fMRI)
as well as the segmentation of the radiation target volume was achieved using Siemens Oncology workstation (Fig. 1B). The speech centres were defined as OARs in the IMRT planning process (mean 45 Gy, max. 50 Gy)(Fig. 1C). The treatment plan (Pinnacle 8.0m TPS, Philips Healthcare, The
Netherlands) was not used clinically and the patient was informed.
Results: Speech activation areas and the GBM (as defined on the T1 MRI
images) could be visualised separately. The plan did not compromise anyother constraint and spared the critical structures. The mean and maximum
doses to the PTV (60 Gy prescribed to 100%) were 61.97 Gy and 69.47 Gy
respectively. Broca’s area was partially within the PTV, however the mean
and maximum doses to Wernicke’s area were 36 Gy and 52.81 Gy (Fig. 1C).
Figure 1. A) CT scan, B) Broca’s and Wernicke’s areas as detected by fMRI
and C) axial slice through radiation treatment plan.

S 319

818 poster
AN INVESTIGATION OF SEQUENTIAL BOOST IMRT VERSUS SIBIMRT FOR HEAD AND NECK CANCER
H. Takegawa1 , S. Nakamura2 , K. Miyagi2 , Y. Kawaguchi2 , O. Suzuki2 , K.

Conclusions: Our 3-D CT/fMRI fusion protocol provides a method to localise
the speech centres and thus to define them as OARs for clinical radiotherapy
planning. This novel technique enables the first steps towards the individualisation of radiotherapy treatment planning for selected patients with glioma,
where the tumour does not overlap the speech areas. [1] Berberat et al. Radiother Oncol 96: Suppl. 1; 1136, 2010

Nishiyama2
1
O SAKA U NIVERSITY G RADUATE S CHOOL OF M EDICINE, Medical Physics
and Engineering, Osaka, Japan2O SAKA M EDICAL C ENTER FOR C ANCER AND C ARDIOVASCULAR D IS EASES , Radiation Oncology, Osaka, Japan816 poster

Purpose: To compare dose volume histograms (DVHs) of sequential boost(SEQ) intensity-modulated radiation therapy (IMRT) with those of simultaneous integrated boost (SIB) IMRT plans for head and neck cancer patients.
Materials: Three patients with nasopharyngeal cancer (T1-2N1) and 3 patients with oropharyngeal cancer (T2N2b) were selected for this analysis. The
SIB IMRT plans were retrospectively generated for comparison. In the SEQ
IMRT, 40 Gy were delivered in 20 fractions to the planning target volume ofthe elective volume (PTVCTV), and further 30 Gy were delivered in 15 fractions to the gross tumor volume (PTVGTV). In the SIB IMRT, 56 and 70 Gy
were delivered in 35 fractions to PTVCTV and PTVGTV, respectively. The
two types of plans were compared with respect to DVHs, and other dosimetric indexes of PTVCTV , body, and carotid arteries.
Results: The mean doses to PTVCTV were 62.6 Gy for SEQ IMRT,
whereas they were 65.7 Gy for SIB IMRT. The mean body V40/50/60 were
10.4/5.6/3.2% for SEQ IMRT and 12.8/8.4/3.7% for SIB IMRT, respectively. In
all cases, the mean doses to the contralateral carotid arteries with SEQ IMRT
were lower with SIB IMRT, by 5.1-15.1 Gy (p < 0.01).
Conclusions: Compared with SIB IMRT, it is possible to reduce doses towhole neck, especially contralateral carotid artery with SEQ IMRT. Further
study is necessary to quantify the long-term clinical impact of this technique.

ALTERNATING CHEMO-RADIOTHERAPY FOR ADVANCED HEAD
AND NECK CANCER: 30 YEARS OF EXPERIENCE IN GENOA
M. Marcenaro1 , R. Corvò1 , A. Bacigalupo1 , G. Sanguineti2 , M. Benasso3 ,E. G. Russi4 , S. Vecchio5 , M. Merlano6
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Radiation Oncology,
Genova, Italy
2
J OHN H OPKINS U NIVERSITY, Radiation Oncology , Baltimore, MD, USA
3
O SPEDALE S. PAOLO, Medical Oncology, Savona, Italy
4
A ZIENDA O SPEDALIERA S. C ROCE E C ARLE, Radiation Oncology, Cuneo,
Italy
5
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Medical Oncology
C, Genova, Italy
6
A ZIENDA O SPEDALIERA S. C ROCE E C ARLE, Medical Oncology, Cuneo,
Italy
Purpose: To review data from advanced HNSCC pts enrolled in several
CTRT clinical trials exploring the alternating approach devised at National
Institute for Cancer Research Genoa, Italy.
Materials: From 1983 to 2010, 662 pts with stage II-III-IV HNSCC/UNPC or
relapsed after surgery were treated with different CT-RT cooperative protocols
aiming to improve outcome and toxicity
Results: The clinical trials were carried out to assess the role and/or timingof alternating CTRT in comparison to conventional or accelerated RT and toevaluate how to safely intensify this strategy. These issues were addressedby a phase III randomized trial (HN7) published in 1988 and updated in 1991:
116 pts were randomized to receive sequential CT(VBML)RT vs alternated
CTRT (ALT-VBML). The ALT-VBML RT arm had better complete response,
PFS and OS but worse mucosal toxicity. Results from two subsequent phase
II trials published between ’88 and ’90 showed good results with mild toxicity
in 34 pts treated with ALT CT (Cisplatin-5FU)RT and good results with hightoxicity in 16 pts treated with the CT (Cisplatin-5Fu) alternated with RT given
in 2 courses of 32 Gy/10 fx/2Gy Bid each. Owing to the interesting resultsof the platin based ALT CTRT, in 1996 the results of a second phase III trial(HN8) that addressed the question about the superiority of ALT CTRT over RT
alone were published: data from 157 pts showed significantly better results for
the ALT CTRT group. In 1997 a comparison between the HN7 and HN8 arms(273 pts) showed better outcome in pts treated with CDDP ALT CTRT. In 2001
data from a phase III randomized trial (HN9) showed in 136 patients no better
results with ALT CTRT when compared with partly accelerated RT (PART). In
2008 we explored ALT CTRT after induction CT in 50 pts with stage IV UNPC
with excellent outcome (OS 81%9 . Between 2001 and 2008, data from three
trials, addressing the question if different doses of a strong radiosensitizer
as Gemcitabine added to ALT CTRT could further improve outcomes, were
published. As 2 trials (9 and 47 pts) with different full doses of GEM added to
ALT CTRT showed good results in terms of outcome but high rates of grade
III-IV toxicity, a third trial (47 pts) with low doses of GEM added to ALT CTRT
was performed with improved long term outcome and an acceptable increaseof mucosal toxicity. The step forward further improvement of outcome andtoxicity profile has been made with the ALTERC trial which has explored thebenefit of adding to ALT CTRT a biologic agent as Cetuximab given weekly
concurrent to RT. Data published in 2010, from the 45 pts enrolled, show highrates of CR and good toxicity profile. Results are shown in tab 1

Conclusions: During the last 3 decades many efforts have been made to
improve advanced HNSCC pts prognosis while keeping toxicity to an acceptable level. We recorded good clinical results with platin based ALT CTRT
regimens in the first trials and investigated the activity of a radiosensitizer ora biologic agent to the same CTRT regimen with encouraging results despite
worse toxicity.
817 poster
AN ANALYSIS OF THE IMPACT OF XEROSTOMIA ON THE QUALITY
OF LIFE OF HEAD AND NECK CANCER PATIENTS RECEIVING
RADIOTHERAPY.
A. Fallon1 , P. Sloane2 , M. Coffey1 , A. Craig1
1
T RINITY C OLLEGE D UBLIN, Discipline of Radiation Therapy, Dublin, Ireland
Republic of2
T RINITY C OLLEGE D UBLIN, Dept. Clinical Speech Language Studies,
Dublin, Ireland Republic ofPurpose: This study aimed to investigate the experience of acute xerostomia and the impact on quality of life among head and neck cancer patients
receiving radiotherapy. The study also aimed to investigate which methods
and products were used by patients to manage their oral problems.
Materials: Patients undergoing radiotherapy for a head and neck malignancy
were given information on the study by the Information and Support Radiation Therapist (ISRT) during their first day in the department. Patients who
signalled interest in participation in the study returned a completed returnedto the ISRT during the third week. The tools used in the study consisted of a)a brief questionnaire, relating to demographics b) the University of Michigan
Xerostomia-related Quality of Life Scale (XeQoLS) and c) the Eating Assessment Tool 10 question format (EAT-10) (Belafsky et al. 2008). The XeQoLS
section consists of fifteen questions relating to perceived quality of life. The
EAT-10 was used by participants to rate eating ability or the self-perceived
level of dysphagia. The XeQoLS and EAT-10 have been validated and usedclinically in studies to date. Both scales were scored in accordance with the
instructions.
Results: Recruitment in this study is ongoing and the interim results arepresented here. A total of 5 respondents have participated in the study todate. All respondents in this study were male with the youngest participant
in the 41-50 age range and the oldest in the over 75 category. The interim
results show that patient’s QoL was reduced during their RT treatment, due to
Xerostomia. Patients were quite anxious and nervous about their problems
and felt that their daily lives were affected greatly by this. Some oral products and methods were used by participants in this study, particularly BMX
mouthwash® and Gingival toothpaste and mouthwash® . The final results of

819 poster
BRAIN TUMORS BRACHYTHERAPY BY USING IR192
R. Mickevicius1 , A. Burneckis1 , E. Aleknavicius1
1
I NSTITUTE OF O NCOLOGY V ILNIUS U NIVERSITY, Vilnius, Lithuania
Purpose: To design a methodology of the insertion the catheters into brain
the tumor’s cavity. We used rigid Ir 192 catheter with VariSource system forhigh dose rate (HDR) brachytherapy in the different types brain tumours.
Materials: Over the 2 year 12 patients were treated: 6 patients with recurrent
glioblastoma multiforme (GBM), 2 patients with recurrent anaplastic astrocitoma (AA), 3 patients with metastatic tumours (MTS) and 1 patient with recurrent anaplastic meningioma. Minimum Three Ir192 catheters were placedin the resection cavity at the time of surgical resection. We used an original
method to insert and fix the catheters in the brain; Low-dose rate radiation
was delivered locally into previously calculated and designed shape of tumour by VariSource systemThey received radiation therapy using the Ir 192
to a mean dose of 24 Gy and Single local dose 6Gy. Catheters were keeptfrom 4 to 7 days depending the dose. All patients had confirmed pathology of
the tumour. The median Karnofsky performance status (KPS) was 80.
Results: All patients were followed-up over the year. At the time of analysis
3 patients with anaplastic Astrocitoma and MTS showed no radiological signsof tumour progression. However all patients with GBM and one with AA has
tumor progression. Acute side effects were wound infection and liquorhea inthree cases. Two patients got mild-nausea and/or headache. 2 incidents ofsymptomaticradiation necrosis with surrounding edema were observed.
Conclusions: We designed original safe system to use rigid IR192 wire forbrachytherapy that allowed to create a precise shape of radiation field andprecisecalculated dose of radiation in functional sites of the brainTreatment
was generally well tolerated.
820 poster
CANCERS OF THE PHARYNX AND LARYNX IN THE PEDIATRICPOPULATION
A. Salem1 , J. Khader1 , L. Y. Mula-Hussain1 , I. Jaradat1 , A. Dayyat1 , S.
Hashem1 , A. Al Mousa1
1
K ING H USSEIN C ANCER C ENTER, Department of Radiation Oncology,
Amman, Jordan
Purpose: Cancers of the pharynx and larynx in the pediatric population are
extremely rare. Squamous cell carcinoma of the head and neck in a child wasS 320H EAD N ECK CANCER

H EAD N ECK CANCER

first described in 1868. Since then, few reports have addressed this uncommon but important topic. We present an account of childhood and adolescentmalignancies arising from the pharynx and larynx with focus on pathologicalfeatures, anatomical locations, therapeutic regimens and disease outcomesof this poorly understood disease entity.
Materials: Review of relevant literature addressing pharyngeal and laryngeal
cancer in the pediatric population. We performed an exhaustive MIDLINE
database search using the following keywords; "pharynx", "larynx", "head andneck cancer", "SCCHN" and "pediatric". Sixteen papers were included in thisreview. Papers were included if they reported patients ≤18 years of age at
the time of diagnosis.
Results: Embryonal rhabdomyosarcoma is the third most common extracranial solid tumor in childhood, however, the incidence of this malignancy in thepharynx and larynx of children is extremely low. Our literature review yielded
19 cases of laryngeal SCC in 5 published reports. We failed to return any pharyngeal SCC cases in the literature. Mucoepidermoid carcinoma is the mostfrequent malignancy of the salivary glands in adults; however, it rarely occurs
in children. A review of literature returns 7 mucoepidermoid carcinomas ofthe palate and larynx in the pediatric population. Delays in the definitive diagnosis of these tumors frequently occur since underlying symptoms are often
attributed to the physiological voice changes during puberty or the upper respiratory tract infections prevalent at that stage of maturity. The choice of initial
therapy in these patients should be guided by clinical stage, histological typeand anatomical location of the primary lesion. However, there is an unspoken
inclination among head and neck surgeons to avoid mutilating surgeries inchildren and adolescents.
Conclusions: This literature review represents a detailed report addressing
pharyngeal and laryngeal neoplasms in childhood and adolescence. Numerous difficulties are encountered in diagnosis and treatment of these cases.
As such, these patients are probably more appropriately managed at a multidisciplinary level.
821 poster
CHEMO-RADIOTHERAPY AS A PRIMARY MODALITY FOR LOCALLYADVANCED HEAD AND NECK CANCERS: TWO YEAR SURVIVALAND TOXICITY OUTCOMES FROM A REGIONAL CANCER CENTRE
IN UK
R. Dandamudi1 , L. Fresco2
1
U NIVERSITY H OSPITALS C OVENTRY AND WARWICKSHIRE NHS T RUST,
Arden Cancer Center, Coventry, United Kingdom
2
U NIVERSITY H OSPITALS C OVENTRY, Arden Cancer Center, Coventry,
United Kingdom
Purpose: To evaluate the 2-year cause-specific and overall survival (OS),loco-regional control rates, acute severe and late toxicities of locally advanced
Head and Neck cancer patients treated with Primary Chemo-radiotherapy(CRT) over a two year period. We have also compared our results against
the international standards published in the literature.
Materials: Between June 2006 and May 2008, sixty three patients with locallyadvanced Head & Neck cancer who had not undergone previous surgery
were treated with primary CRT with a curative intent. Three patients diedduring treatment due to disease-related problems, leaving 60 patients available for analysis. All were Squamous cell carcinomas, involving Oropharynx(63.3%), Nasopharynx (8.3%), Supraglottis (11.6%), Glottis (6.6%) and Hypopharynx (10%). Overall, Stage 3 were 17 patients (28.33%), Stage 4A
were 39 patients (65%), Stage 4B were 4 patients (6.66%). Primary CRT
was delivered using concurrent 3 weekly Cisplatin (75-80 mg/m2 ) and radiotherapy dose of 66-70 Gy in 33-35 fractions, treated daily in three phases byconformal 3-dimensional CT-planning. Treatment response was assessed radiologically 3 months post primary CRT. Survival was calculated from the timeof histological diagnosis and Time to Treatment Failure (TTF) from the completion of treatment. Radiation related acute severe (grade 3/4) and late toxicities were classified according to Radiation Therapy Oncology Group (RTOG)
criteria. 2-year cause-specific survival was calculated using Kaplan-Meiercurves.
Results: The median age was 57 years (range 18-79) with a Male: Female
ratio of 3:1. Out of 60 patients who have completed intended treatment, the2-year OS was 73.3 % and loco-regional control rate was 86.6 %. The primary treatment failure rate was 13.3 % (8/60 patients) of which 3 patients
had residual disease at 3 months imaging and rest of the 5 had loco-regional
recurrence. The median TTF was 8 months (range= 1 to 15 months). Sixteen patients (26.6%) died with in 2 years of treatment of which eight patients(13.3 %) died of loco-regional disease progression and five patients (8.3%)
died of distant recurrence. Remaining three died of other causes including
two (3.3%) from second primary (lung and oesophageal) cancers. The incidence of acute severe or persistent oral mucositis was 8.3 % (RTOG grade
3) and none had grade 3/4 skin toxicity. The incidence of late toxicities was
8.3 % for Osteoradionecrosis (ORN) of the mandible, 6.6 % for severe trismus and 1.6 % had sinus formation. The incidence of severe oropharyngeal
stenosis/ total dysphagia was 6.6 % and 3 patients (5 %) were on long term
(15-32 months) gastrostomy feeding tube for nutrition. None of the patients
had treatment related death.
Conclusions: The 2 year survival and loco-regional control rates for locallyadvanced head & neck cancers treated with primary CRT (conventionally)

from this single institute in UK were on par with international standards published in the literature. The incidence of acute severe and late toxicities was
below 9 %.This data will be followed up for long-term outcomes and can beused as a bench mark for comparison with current modern planning techniques like Intensity Modulated Radiotherapy (IMRT).
822 poster
CHK1 DELETION SUPPRESSES TUMOURIGENESIS IN A NOVELIN VIVO MODEL FOR SQUAMOUS CELL CARCINOMA AND ENHANCES IN VITRO CYTOTOXICITY OF THERAPIES RELEVANT TO
HEAD AND NECK SCC
L. Tho1 , G. Zachos2 , E. Black2 , R. Rampling2 , D. Gillespie2
1
B EATSON I NSTITUTE FOR C ANCER R ESEARCH, Cell and Molecular Biology,
Glasgow, United Kingdom
2
B EATSON I NSTITUTE FOR C ANCER R ESEARCH, Glasgow, United Kingdom
Purpose: Chk1 is a key regulator of DNA damage response and genome
stability in eukaryotes. Recent evidence has shown that inhibition of DNA
damage repair mechanisms in tumours (eg. PARP inhibition) can be exploited
as a novel anti-cancer strategy and Chk1 inhibition similarly, is under exploration. However in vivo models relevant to squamous cell carcinoma (SCC)
are required before this strategy can be advanced.
Materials: A novel murine model for SCC was developed in order totest the effects of chk1 gene deletion on SCC tumourigenesis. Keratin14
driven Cre-ER expression was used to conditionally delete loxP flanked
chk1 in squamous epidermis. 7,12-dimethyl-benz[a]anthracene /12-O-tetradecanoyl-phorbol-13-acetate chemical carcinogenesis was used to induce tumours. 5-bromo 2-deoxyuridine label retaining techniques were used to identify and track tissue stem cells. An in vitro chk1 -/- cancer cell line was used
to test sensitivity of chk1 loss to radiotherapy and chemotherapy.
Results: A novel conditional chk1 murine model was successfully developed.
Complete deletion of chk1 suppressed papilloma and carcinoma tumour formation. The few tumours that managed to form were smaller, displayed increased latency and always retained Chk1 expression. Chk1 loss was accompanied by an accumulation of DNA damage and cell apoptosis. This led
to stem cell recruitment out of quiescence in order to maintain homeostasis
and the phenotype of the mouse was unaffected. There was enhanced cellkilling of chk1 -/- cancer cells when subjected to megavoltage γ -irradiation,
cisplatin and 5-fluorouracil.
Conclusions: We have developed a novel murine model to test chk1 deletionin vivo, with particular relevance to SCC. Checkpoint kinase chk1, is essential
for the survival of incipient cancer cells and deletion significantly suppresses
tumourigenesis. Minimal toxicity was recorded and chk1 deletion was welltolerated. Chk1 loss in cancer cells sensitizes them to cytotoxicity in combination with therapies relevant to head and neck SCC.
823 poster
CLINICAL OUTCOME OF PATIENTS WITH LOCALLY ADVANCEDHEAD AND NECK CANCER TREATED BY INDUCTION CHEMOTHERAPY FOLLOWED BY CHEMORADIATION
J. O. Brömme1 , J. Vock1 , A. Arnold2 , A. Geretschläger1 , B. Klaeser3 , P.
Zbären2 , D. Rauch4 5 , T. Krause3 , D. M. Aebersold1 , M. Schmuecking1
1
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Radiation
Oncology, Bern, Switzerland
2
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of ENT and HNS,
Bern, Switzerland
3
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Nuclear
Medicine PET , Bern, Switzerland
4
S PITAL STS AG, Department of Oncology and Haematology, Thun,
Switzerland
5
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Oncology andHaematology, Bern, Switzerland
Purpose: Induction chemotherapy followed by definitive chemoradiation(CRT) has emerged as an option for the treatment of patients with locallyadvanced squamous cell carcinoma of the head and neck. In this setting,the most studied induction regimen is docetaxel, cisplatin, and 5-fluorouracil(TPF). However, the role of induction therapy remains to be fully validated bystudies comparing TPF followed by CRT versus CRT alone. In addition, it
remains unclear if patients with a complete metabolic remission after TPF as
detected by PET or complete morphological remission as detected by MRI or
CT should receive the same radiation dose as compared with patients withpartial remission or no change of disease.
Materials: Between 2006 and 2010, 36 patients suffering from locally advanced squamous cell cancers of the oral cavity, oropharynx or hypopharynx(stage III-IVM0 SCCHN) were treated with two to three cycles of induction
chemotherapy (n = 26: TPF q3w or n = 13: TP q3w) followed by definitive
chemoradiation (72 Gy to the regions of gross tumor with a margin of 15mm
from GTV to CTV taking into account anatomical boundaries, and a marginof 3mm from CTV to PTV). Initial staging consisted of MRI or CT, in 19 outof 36 patients additionally of 18F-FDG PET/CT. After induction chemother-

apy restaging was done by MRI or CT; in 9 out of 19 patients additionallyby a second 18F-FDG PET/CT to evaluate the metabolic remission prior tochemoradiation. Mean time for follow-up was 11 months (range 2 months 41
months).
Results: Complete remission (CR) after induction chemotherapy was observed in 6 out of 36 patients (17%), partial remission (PR) in 24 out of 36
patients (66%), no change / progressive disease (NC, PD) in 6 out of 36 patients (17%), 3 patients with complete metabolic remission as detected by
PET showed only a partial remission in their MRI or CT studies. Acute grade
III/IV side effects were noted in 15 out of 36 patients (42%). Main toxicities
were afebrile leucopenias, neutropenias, stomatitis and dysphagia. 1 year
recurrence free survival is 77% (sd +10%), 3 year recurrence free survival
is 53% (sd +16%), median recurrence free survival is 34 months (sd + 10
months). 3 year overall survival is 66% (sd + 27%). All patients with NC
or PD (n = 6) after induction chemotherapy survived less than 34 months;
all patients with a complete metabolic remission had no recurrence duringfollow-up (range 3 months 17 months).
Conclusions: Induction chemotherapy with TPF or TP followed by chemoradiation seems to be an effective treatment in patients with unresectable advanced head and neck cancer with a considerable toxicity that needs special expertise which is best assured in a multidisciplinary setting. Our data
are comparable with the international literature. Metabolic remission as detected by PET precedes morphological remission as detected by MRI or CT.
Randomized studies are warranted to optimize clinical outcome with reduced
toxicity.

S 321

toxicity and local control
Materials: All recurrent carcinoma tongue, without neck node treated between Jan 2010 to Oct 2010 by Cyberknife robotic radiosurgery were analyzed. All patients underwent minimum 3 gold fiducials placement into the
tongue. They were immobilized with orfit cast and vacloc. Planning PET CT
simulation and MRI were used for delineating Gross tumor volume and Clinical target volume. All patients were treated with 24Gy in 3 fractions to CTV.
The fiducial tracking method was used during treatment by cyberknife. The
cases were analyzed for tolerability, toxicity. All patients underwent reassessment after 3 months for the response.
Results: Five cases were eligible, all were male, mean age was 55 years[39-78].Mean GTV volume was 27cc [13.54 - 48.77 cc], Average number ofbeams used was 220 [163 - 285],nodes 83.30 % isodose surrounding target
was within 15mm.Fiducial tracking during the treatment delivery was easy.
All the patients tolerated the treatment well. None of the patients had Grade
3 toxicity at the end of 3 weeks. The symptomatic pain relief was there in
all patients. All the patients responded to treatment.4 patients had complete
metabolic [PET] response, 1 patient had partial response.

824 poster
CONSERVATIVE TREATMENT WITH BRACHYTHERAPY FORUVEAL MELANOMA: MORE THAN 300 CASES FROM THE INSTITUTCATAL À D’ONCOLOGIA
C. Gutiérrez Miguélez1 , J. Pera1 , J. M. Cminal Mitjana2 , E. Martinez1 , J. M.
Piulats1 , F. Guedea2
1
I NSTITUT C ATALÀ D ’O NCOLOGIA, L’Hospitalet de Llobregat, Spain
2
H OSPITAL DE B ELLVITGE P RINCEPS D ’E SPANA, Barcelona, Spain
Purpose: Brachytherapy in uveal melanoma is the treatment we use in our
hospital to conserve the eye. In our study we want to know our results inlocal control, survival and vision, and to compare our results with the ones
published by other authors.
Materials: About 300 patients diagnosed with uveal melanoma were referedto our hospital for treatment. The oftalmologist visited them to confirm thediagnosis by ultrasound and measure the tumor (height and diameters) andthe distance to the organs at risk, the optic nerve and the macula. All ofthem were studied with hepatic ultrasound, torax X-ray and blood analysis
to confirm there were not distant metastases.The patients were treated withbrachytherapy with 125-Iodine, using the COMS applicators. The applicator
was chosen to cover the maximum diameter of the tumor plus a margin of 2mm. A dose of 75 Gy to the tumor apex was administered.
Results: With a mean follow-up or 3.6 years, overall survival is 100%, 82%
and 76% depending on the size of the tumor. 16% developed distant metastases and were refered for surgery or chemotherapy, although their prognosis
is very bad. 6.8% of the patients were enucleated due to relapse or otherlocal causes. 38% of the patients maintain a good vision and 60% an usefulvision.
Conclusions: Conservative treatment for uveal melanomas with brachytherapy obtains the same survival results that enucleation and mantains an acceptable vision in most cases. Our results are similar to those published byother authors.
825 poster
CYBERKNIFE ROBOTIC RADIOSURGERY FOR RECURRENTCARCINOMA TONGUE
S. Papaiah Susheela1 , R. Bilimagga2 , P. A3 , J. A3 , G. M J4 , K. Swamy1 , K.
Kallur5 , S. Battachraji1 , A. K. BS1
1
HCG B ANGALORE INSTITUE OF ONCOLOGY S PECIALTY CENTER, Radiotherapy and Oncology, Bangalore, India
2
HCG B ANGALORE INSTITUE OF ONCOLOGY S PECIALTY CENTER, Bangalore, India
3
HCG B ANGALORE INSTITUE OF ONCOLOGY S PECIALTY CENTER, Physics,
Bangalore, India
4
HCG B ANGALORE INSTITUE OF ONCOLOGY S PECIALTY CENTER, Radiology, Bangalore, India
5
HCG B ANGALORE INSTITUE OF ONCOLOGY S PECIALTY CENTER, Nuclear
Medicine, Bangalore, India
Purpose: The management of recurrent carcinoma tongue is challenging
when the lesion is inoperable or patient refuses surgery. The reiiradiationby conventional methods have limitations in terms of tolerability, toxicity andlocal control. The role of Cyberknife robotic radiosurgery is less explored inthese types of tumors. This study looks into role of Cyberknife Robotic Radiosurgery using fiducial tracking for recurrent carcinoma tongue, its tolerability,

Conclusions: Cyberknife Robotic Radiosurgery using fiducial tracking forrecurrent carcinoma tongue is well tolerated with minimal toxicity and good
local control. Long term follow-up and randomized trials will be required toprove this fact.
826 poster
DEVELOPING BIOMARKER ASSAYS FOR DNA DOUBLE STRAND
BREAKS
K. Shah12 , C. Clelland3 , K. A. Shah3 , A. Salisbury2 , K. A. Vallis12
1
G RAY I NSTITUTE FOR R ADIATION O NCOLOGY & B IOLOGY, U NIVERSITY OF
OXFORD, Oxford, United Kingdom
2
OXFORD C ANCER C ENTRE , C HURCHILL H OSPITAL, Oxford, United
Kingdom
3
OXFORD R ADCLIFFE H OSPITALS NHS T RUST, Cellular Pathology, Oxford,
United Kingdom
Purpose: To develop a feasible, reliable and robust assay for biomarkers of
DNA double strand breaks using immunofluorescence in tumour fine needle
aspiration (FNA) specimens.
Materials: The DSB Biomarkers Pilot Study was established with regulatory approval to develop the clinical assay. Forty FNA specimens havebeen obtained from seven patients with histologically proven malignancies
including head and neck squamous cell carcinoma, metastatic malignant
melanoma and lung adenocarcinoma. In addition, specimens of peripheral
blood mononuclear cells have been separated and irradiated ex vivo as astaining control.
Results: FNA sample handling and staining procedures have been developed. Specimens obtained before and after external beam radiotherapy havebeen used to demonstrate an increase in the number of foci of gamma-H2AX
with irradiation. These differences have been quantified using automated image analysis.
Conclusions: A biomarker of DNA double strand breaks can be demonstrated and quantified in tumour fine needle aspirate specimens using a novel
assay. The study continues in order to establish the robustness of the method
and the variability in quantification.

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827 poster
DNA DAMAGE AND REPAIR IN PERIPHERAL BLOOD LYMPHOCYTES IN A LI FRAUMENI PATIENT
M. Worku1 , N. Fersht1 , S. Short1
1
UCL C ANCER I NSTITUTE, Oncology, London, United Kingdom
Purpose: Li Fraumeni syndrome (LFS) is a hereditary cancer predisposition
syndrome that is characterized by a familial clustering of tumours, with a predominance of sarcomas, breast cancers, brain tumours, and adrenocorticalcarcinomas, diagnosed before the age of 45 years. Germline mutations of
the tumour suppressor gene p53 have been identified in approximately 70%
of families. Mutations of Chk2 have also been found in some patients with
LFS. p53 and Chk2 are important in detection and repair of radiation induced
DNA double strand breaks, but the repair defect following radiation-induced
DSB in LF has not been studied in detail. In this study we measured theinduction and repair of DNA damage in a patient with family history of LFS
compared to an unaffected control.
Materials: Peripheral blood samples were collected from a patient diagnosed
with a glioma and with a familial history of LFS and from normal control. Lymphocytes were separated from 8 ml whole blood using ficol method and resuspended in RPMI medium supplemented with 10% serum and penicillin
and streptomycin. Lymphocyte culture was divided into two parts and irradiated with 0Gy or 2Gy X-Ray and incubated at 37o C and 5% O2. After 1h and24h cells were fixed and stained with phospho-serine139 γ H2AX antibody
and γ H2AX foci were counted using confocal microscopy.
Results: A low basal level (0.34 and 0.19) foci/cell was found in the control
and the LFS patient respectively. Irradiation of lymphocytes with 2Gy X-Ray
induced 11.95 foci/cell for the control and 24.70 foci/cell of LFS patient at 1
hour. 24h after 2Gy irradiation 0.19 foci/cell (7.8%) in the control and 3.16
foci/cell (12.9%) in LFS remained.

Purpose: The Ottawa Hospital Cancer Centre (TOHCC) has commenced aphase I/II dose escalation study of multiple myeloma patients with autologous
hematopoietic stem cell rescue using Helical Tomotherapy (HT) to treat theentire bone marrow. Three Total Marrow Irradiation (TMI) patients have beentreated to a dose of 14Gy in 7 fractions (BID) since January 2010. Although
TMI treatments have been previously delivered in other centres, those patients were treated with radiation alone, without chemotherapy. The TOHCC
clinical trial plans to dose escalate by 2Gy every three patients to a final total
dose of 28 Gy in 14 fractions BID.The following work will describe treatment
preparation, planning and the technical aspects of treatment.
Materials: Patients are immobilized using a head and neck shell(Aquaplast/Qfix Systems™), a torso/pelvis and lower limbVac-Lok™. Bolus(5mm) is conformed around hands, knee caps and feet to ensure accurate
dose coverage. Two scans, an upper and lower body, are performed usinga CT scanner (Philips Gemini). Once the scans are fused, all OARs andbones are contoured, expanded by various margins and one PTV is created.
A smooth junction region is created by using a range of doses to various junction PTVs. A 2.5cm beam was used for the superior plan in order to reducedose to critical structures while a 5.0cm beam was used for the inferior plan.
Once the plan was calculated (on a fine grid) the total time for the treatment
planner to optimize the plan was 8 hours
Results: Figure 1 demonstrates an example a DVH for the PTVs and selectsensitive structures in the upper body. ImageI software was used to sum thedose from the superior and inferior plans to determine the total dose distribution in the whole patient, including the junction region. There were someclinically acceptable hot spots in the junction area due primarily to the threadeffect in the extremities. DQAs were delivered and analyzed in several regions, including the junction area, and the results showed good agreement,
indicating that our method for fusing and junctioning is effective. The averagetreatment time was 54 minutes. During treatments, in addition to the initial
setup adjustments, scheduled interruptions were performed in order to ensure reproducibility. The average shifts after the interruption on the superiorplan were 2.9mm in the left and right direction and 0.5mm in the anterior andposterior direction. No superior or inferior shifts were performed after the initial setup adjustments. The average shifts for the inferior plan were -4.0mm
left/right and 8.3mm anterior/posterior. Larger PTV margins are used for the
lower plan in order to account for the greater variability.
Conclusions: Treatments have been well tolerated by all three patients, withminimal acute toxicities. Despite the junctioning challenges, this treatment
technique is feasible and we expect to be able to continue dose escalate.
829 poster
EARLY AND LATE PERFUSION AND VOLUME CHANGES IN
SALIVARY GLANDS AFTER RADIOTHERAPY MONITORED BY MRI
T. Schakel1 , A. Houweling1 , C. van den Berg1 , J. M. Roesink1 , C. Terhaard1 ,N. Raaijmakers1 , M. Philippens1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands

Conclusions: These data suggest a change in radiation induced DSB induction and repair in LFS compared to control consistent with a radiosensitive
phenotype.
828 poster
DOSE ESCALATION TRIAL OF MULTIPLE MYELOMA PATIENTS BY
TREATING TOTAL MARROW USING TOMOTHERAPY
L. Montgomery1 , H. Atkins2 , G. Fox1 , L. Gerig3 , K. Carty1 , G. Niedbala3 ,B. Nyiri3 , R. S. Samant1
T HE OTTAWA H OSPITAL C ANCER C ENTRE, Department of Radiation
Oncology, Ottawa, Canada
2
T HE OTTAWA H OSPITAL, Department of Hematology and Oncology,
Ottawa, Canada
3
T HE OTTAWA H OSPITAL C ANCER C ENTRE, Division of Medical Physics inRadiation Oncology, Ottawa, Canada
1

Purpose: The most common side effect of radiotherapy (RT) in patients withhead-and-neck cancer is xerostomia. However, the exact changes in the salivary glands leading to xerostomia are not known. In this study, the short andlong term radiation induced changes in the salivary glands were investigated.
Materials: Six oropharyngeal cancer patients underwent an MRI exam on
a 3T scanner (Achieva, Philips Medical Systems) before RT and at 6 weeks
and 1 year after the end of RT. To allow registration with pretreatment dose,patients were scanned in their immobilization mask in treatment position.
Laterally located surface coils were applied as receiver coils. The imaging
protocol consisted of a T2 weighted (TR/TE/TSE = 4200/130 ms/15) and a
DCE-MRI (TR/TE/FA = 4.0/1.0 ms/13◦ ) sequence. The DCE-MRI consistedof 45 acquisitions with time interval 2.0 s, contrast agent (Gadovist) was injected.All patients underwent stimulated salivary flow measurements using
Lashley cups.The parotid and submandibular glands were delineated on the
MR images for each time point separately. The signal intensity of the T2
weighted images was normalized to the signal intensity in the brainstem.
The DCE-MRI images were converted to contrast concentration. Extracted
concentration-time curves were analyzed using the pharmacokinetic Tofts
model.Radiation dose maps and MRI were rigidly registered using mutual
information in the Elastix software. The mean dose and the median value foreach MRI parameter, in the delineated region were used for analysis. The differences were tested for significance using a Wilcoxon matched-pairs signed
rank test and for correlation with the mean planned dose using Pearson’s
correlation (GraphPad Prism 5.03).
Results: Early effectsA decrease in volume was observed in parotid (24%)
and submandibular (30%) glands. Average salivary flow decreased with 63%.
On average, T2 (21%), ve (73%) and vplasma (142%) increased significantly.
The gland perfusion parameters varied widely and correlated with dose (upto R=-0.8 for Ktrans ). Glands receiving a lower dose showed an increased
perfusion while glands receiving higher dose levels showed lower perfusion(figure).Late effectsThe glands did not shrink further after 6 weeks. Salivary flow decreased with 83% on average compared with baseline flow. Ve
renormalized to its level before RT, while Ktrans , kep and vplasma significantly
decreased below baseline values.

S 323

Conclusions: PPEG decreased the rate of progression and severity ofgrade-3 weight loss in nasopharyngeal carcinoma patients who received concurrent chemo-radiation followed with adjuvant chemotherapy.
Conclusions: Radiation induced early and late changes after RT were observed in the parotid and the submandibular gland using MRI. The glandvolume was decreased 6 weeks after RT and stabilized hereafter. Glands
receiving a low dose showed an acute increase in perfusion, corresponding
with the development of edema, followed by a late impaired perfusion. Moreover, glands receiving a higher dose showed lower perfusion which was also
followed by late impairment of perfusion.

831 poster
EVALUATION OF DOSE PROFILES OF GAMMA KNIFE USINGEGSNRC CODE AND PAGAT GEL DOSIMETER
T. Allahverdi Pourfallah1
1
M AZANDARAN U NIVERSITY M EDICAL S CIENCES, Biophysics and Biochemistry, Sari, Iran Islamic Republic of

830 poster
EFFECT OF PROPHYLACTIC PEG ON WEIGHT LOSS DURINGCHEMO-RADIATION IN PATIENTS WITH NASOPHARYNGEALCARCINOMA
T. Peerawong1 , R. Sagthong2 , T. Phungrassami1 , K. Pruegsanusak3
1

P RINCE OF S ONGKLA U NIVERSITY, Radiology, Songkhla, Thailand
P RINCE OF S ONGKLA U NIVERSITY, Epidemiology, Songkhla, Thailand
3
P RINCE OF S ONGKLA U NIVERSITY, Otolaryngology/Head and Neck
Surgery, Songkhla, Thailand
2

Purpose: To examine the effect of prophylactic PEG on weight loss in locallyadvanced nasopharyngeal carcinoma (LANSP) treatment.
Materials: The data of LACNSP patients who received concurrent chemoradiation in Songklanagarind hospital during Jan 2004 December2009 reviewed. Inclusion criteria were patients with stage Ib and IVa squamouscell carcinoma; age above 18 years; Eastern Cooperative Oncology Group(ECOG) ≤ 2, available medical records in both radiation oncology and otolaryngology clinics. Patients were excluded if having metastasis during treatment or had other treatment regimens.Treatment regimenRadiation treatment with conventional or three dimensional radiotherapy techniques was
performed. The radiation doses were 70 Grey (Gy) in 35 Fractions (F) 5 F
per week for gross tumor and 50Gy in 25 F 5 F per week for microscopic disease with cobalt machine or 6-MV linear accelerator.Five cycle of chemotherapy were given. Cisplatin 100 mg/m2 or Carboplatin AUC5 gave every three
weeks at an out-patient unit in concurrent phase. In adjuvant phase, Cisplatin
75-80 mg/m2 or Carboplatin AUC5 on day 1 and 5-FU 1000 mg/m2 on day
1-4 were administrated every 4 weeks. In-patients admitted to the hospital.
. The selected treatment regimens and dose adjustment based on patients’conditions and physician’s judgment. Weight in kilogram was recorded atbaseline and in subsequent treatments. W eight loss defined by a reductionof weight at each point from baseline and then classified into grade1-3 basedon common toxicity criteria adverse event version 3 including loss of 5-10%,
10-20%, and >20% of baseline. Chi-square and Fisher’s exact tests wereused for data analysis at p-value < 0.05
Results: Patients categorized into PPEG (n=77) and non-PPEG group(n=142). No significant difference in baseline characteristics found in the twogroups including sex, age, height, baseline weight, histology, staging, typeand schedule of chemotherapy, radiation dose, completed of radiation treatment and total treatment time. However they differed in ECOG performancestatus and co-morbidity namely chronic obstructive pulmonary disease andheart disease. Figure 1 shows a comparison of weight loss pattern between
patients with and without PPEG during 5 cycles of treatment. In the 1st cycle,
most patients in both groups were in grade-1weight loss group whereas 2% ofgrade-3 group found in non- PPEG group. There was no significant difference
between the two groups. Grade-2 and grade-3 weight loss had increased inboth PPEG and non-PPEG groups over time but was more obvious in the
non-PPEG group. By the end of the treatment cycle, grade-3 weight loss
found in non-PPEG group (57%) greater than that in PEG group (8%) without
significant difference (P=0.11) due to small number of population (n=19).

Purpose: In the present study EGSnrc calculated dose profiles along threespatial coordinates were compared with those measured with the MR polymer
gel dosimeter for single-shot irradiations of Gamma Knife unit and seeks toreveal that inserting inhomogeneities inside the Plexiglas head phantom cancause dose disturbances that are not in agreement with predicted accuracyof GK unit.
Materials: A custom-built 16 cm diameter spherical Plexiglas head phantom was used in this study. Inside the phantom, there is a cubic cutout for
inserting of gel cubics and another cutout for inserting the air and Poly-tetrafluoro-ethylene (PTFE) inhomogeneities.PAGAT polymer gel dosimeter was
fabricated according to composition proposed by Venning et al. For fabricating the gel dosimeter, the De Deene et al proposed method have beenused.The evaluation of the polymerized dosimeter was performed on a 1.5 T
clinical Siemens scanner in the transmitter/receiver head coil. A multi-echo
sequence with 32 echoes was used for the evaluation of irradiated polymergel dosimeters. The parameters of the sequence were as follows: TR 3000
ms, TE 22640 ms, slice thickness 1 mm, FOV 128 mm, matrix size 25656,
pixel size 0.5.5 mm2, and one acquisition. The R2 (spin-lattice relaxation
rate, 1/T) were computed using modified radiotherapy gel dosimetry image
processing software coded in MatLab. The R2 matrix was subsequently converted into a relative dose matrix normalized to the maximum prescribed doseof 40 Gy.The EGSnrc-based MC user code BEAMnrc was used to simulate
the geometry of the simplified GK source channel, and outputs phase-spacedata (phase-space files), which include all the particle information (i.e. thecharge, position, direction, energy and history tag for each particle).Anothergeneral-purpose MC EGSnrs user code DOSXYZnrc which considers thephantom divided in a large number of small volume elements, or voxels, wasemployed to obtain the 3D dose distributions in the phantom.
Results: Regarding acceptance criteria for conformal radiotherapy, it is clearthat the GK as a stereotactic radiosurgery unit must conveys such degree of
accuracy. According to values of table 1 within high isodose levels (>80%)
there are dose differences higher than 7%, especially between air inserted
and PTFE inserted phantoms, which were obtained using both simulationand experiment. This means that these values exceed the acceptance criterion of conformal radiotherapy and stereotactic radiosurgery (i.e., within some
isodose levels less than 93% of prescription dose are delivered to the target).
TABLE I. Dose differences (DDs) for MC simulation and PAGAT Polymer gel
dosimeter. Homogeneous vs. air inserted phantoms (DD(H-A)%), Homogeneous vs. PTFE inserted phantoms (DD(H-P)%), and air inserted vs. PTFE
inserted phantoms (DD(A-P)%), in three coordinate axes.

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H EAD N ECK CANCER
ment of Radiological Sciences, Seoul, Korea Republic of5
I NJE U NIVERSITY, S ANGGYE PAIK H OSPITAL, Department of Radiation
Oncology, Seoul, Korea Republic ofConclusions: The discrepancies observed between the results obtained forheterogeneous and homogeneous phantoms suggest that LGP predictions
which assume the target as a homogeneous material must be corrected inorder to take care of the air- and bone-tissue inhomogeneities.
832 poster
EVALUATION OF FRACTIONATED STEREOTACTIC RADIOTHERAPY WITH VAGINA CAROTICA PROTECTION FOR RESIDUAL
NASOPHARYNGEAL CARCINOMA
F. Liu1 , J. Xiao2
1
C HINESE ACADEMY OF M EDICAL S CIENCES, Department of Oncology,
Radiology and Clinical Immunology, Beijing, China
2
C HINESE ACADEMY OF M EDICAL S CIENCES, Beijing, China

Purpose: To evaluate the effect of magnetic field on percent depth dose(PDD) and beam profile of Co-60 and to determine the dose effect in inhomogeneity situation.
Materials: The PDD and beam profile data was calculated by GEANT4 Monte
Carlo Code in the field size of 5x5, 10x10, and 30x30 cm2 under the transverse or longitudinal magnetic field of 0T, 1T, 1.5T, 3T, 7T. The inhomogeneous phantom of the tissue-air-tissue and tissue-bone-tissue was evaluatedwith identical field size and magnetic field strength.
Results: The PDD data corresponded to the published Co-60 beam dataof deviation within 0.35%. Maximum dose depth (dmax) decreased as themagnetic field strength increased under the transverse magnetic field in a
homogenous phantom. The dmax was 4.2mm and 1.5mm when B=1T and
7T, respectively. The beam profile showed no significant changes in Co-60
beam with 1.17 MeV and 1.33 MeV. But significant shift was observed whenthe energy was increased to 6 MeV. There was no meaningful change under
the longitudinal magnetic field.In the situation of tissue-air inhomogeneity, the
PDD showed a peak at tissue-air interface and a decreased plateau at the air
area. This is caused by the electron return effect which was increased until
B=1T and then decreased gradually as the magnetic field strength increased.
In the tissue-bone-tissue inhomogeneity phantom, the reverse pattern wasobserved.
Conclusions: The characteristics of Co-60 beam could be affected by magnetic field. As the magnetic field strength increased, the dmax point was
shifted to the surface which resulted in a decline of skin sparing effect. Hot
and cold spots can be increased in inhomogeneity situation which can result
the higher probability of inappropriate treatment or toxicity to the patients.
834 poster
EXPERIENCE OF A REGIONAL UK CENTRE :TREATING HEAD AND
NECK CANCER WITH TOMOTHERAPY
S. Chatterjee1 2 , R. pearson2 , I. mallick1 , M. robinson3 , C. kelly2
1

TATA M EDICAL C ENTER, Kolkata, India
N ORTHERN C ENTRE FOR C ANCER T REATMENT, Newcastle upon Tyne,
United Kingdom
3
N EWCASTLE U NIVERSITY, Newcastle upon Tyne, United Kingdom
2

Purpose: To evaluate the clinical efficacy and complications of fractionatedstereotactic radiotherapy (FSRT) with vagina carotica protection for locallyresidual nasopharyngeal carcinoma patients after the first course of radiotherapy.
Materials: From August 2006 to August 2010FSRT with vagina carotica protection was delivered to 37 such patients. The patients’ age ranged from 13
to 63 years with a median of 41 years. 25 patients were males and 11 werefemales. Their stages before FSRT, according to the Fuzhou Staging System(1992) were: 8, 8 , a 18, b 2 and UICC Staging System (2002) were:a2, b 8, 16, a 6, b 4. In the first course of radiotherapy, 4 patients received
conventional radiotheraphy and 32 patients received IMRT and 22 patients
received concurrent chemoradiotherapy. The total dose of the first course ofradiotherapy is 69.96-74.92 Gymedian: 70.41 Gy. The interval between thefirst course of radiotherapy and FSRT ranged from 20 to 68 daysmedian38
days. All patients had pathological evidence of locally residual lesions. Target volumes ranged from 875.2 to 26836.7 mm3 median:10418.0 mm3 .90%
isodose curves were chosen for prescribed dose where the total FSRT dose
were12.5-21.0Gymedian:15.0 Gy2.1-4.0Gy per fraction. The typical FSRT
dose were 15 Gy/3 fractions/5 Gy per fraction.The received dose of vagina
carotica was less than 2Gy per fraction.
Results: The median follow-up time is 29 months(2-50 months). The one,two and three-year follow-up rates were 83.3%,52.8%,30.6%.The one-,twoand three-year local control rates were 100%. The one- ,two and three-year
overall survival rates were 100%,97.2%,94.4%. The one- ,two and three-year
disease-free survival rates were 100%,94.4%,91.7%.No patient with cranial
nerve injury and no case with nasopharyngeal massive hemorrhage, ulceration or other serious radiation-related complications was observed.
Conclusions: FSRT with vagina carotica protection is effective and safe for
local residual nasopharyngeal carcinoma with reduction of radiation-related
neurovascular lesions.
833 poster
EVALUATION THE EFFECT OF MAGNETIC FIELD ON CO-60 BEAM
USING GEANT4 MONTE CARLO CODE
C. I. Lee1 2 , T. S. Suh1 , B. Y. Choe1 , W. G. Jeong1 , J. W. Shin3 , S. W.
Hong3 , S. W. Park4 , Y. H. Ji4 , J. Y. Jung5 , S. M. Jeong2
1
T HE C ATHOLIC U NIVERSITY OF KOREA, Department of Biomedical
Engineering, Seoul, Korea Republic of2
Y EIDO S T. M ARY ‘ S H OSPITAL , T HE C ATHOLIC U NIVERSITY, Departmentof Radiation Oncology, Seoul, Korea Republic of3
S UNGKYUNKWAN U NIVERSITY OF KOREA, Physics, Seoul, Korea Republicof
4
KOREA I NSTITUTE OF R ADIOLOGICAL AND M EDICAL S CIENCES, Depart-

Purpose: Helical Tomotherapy (HT) delivers image guided (IGRT) intensity
modulated radiotherapy (IMRT). Head and neck tumour are one of the commonest sites treated using IM/IGRT. The article discusses practical and dosimetric details of the first 52 head and neck patients treated with HT.
Materials: The treatment details of the first 50 patient were retrospectively
analysed for PTV dose, OAR dose (parotid, larynx, mandible, spinal cord,
brain stem, and optic apparatus), beam on time, treatment time, and daily
shifts (X, Y, Z axis as well as roll). Dosimetric audit check and set up shiftchecks were analysed. PTV margin was calculated at 2.5 SE + 0.7RE tocheck if current CTV to PTV margins were adequate such that no check if
daily imaging could be prevented.
Results: 41 patients were treated radically (61% oropharynx, 9.7%Larynx,
7.3% Paranasal sinus, 7.3%Nasopharyngeal cancers) and 9 patients werereceived retreatment. A pitch of 0.287 and field width of 2.5cm was used forall oropharynx cases whereas for nasopharynx cases pitch of 0.43 and field
width of 1cm was used. A modulation factor of 2.4 was used in all cases
apart from 1case with paranasal sinus tumour where a modulation factor of
3 was used . Prescription to high dose PTV (PTV1) ranged from 60Gy (adjuvant) to 65Gy in 30 fractions. The achieved mean and median doses were
within 0.3% of prescribed dose. Median of the mean parotid dose for left andright parotids were 27.6Gy and 28Gy with 92% and 88% parotids receiving
less than 30Gy respectively. Mean larynx dose was 39.2Gy (SD+/-6.2). The
median of the maximum cord and brain stem doses were 25Gy and 30Gy
respectively. Constraints for all the optic apparatus doses were achieved.
When oropharynx patients were analysed separately, the prescribed PTV1
dose was 65Gy and the median achieved was 64.8Gy. Median of the mean
parotid doses was 27.5Gy versus 27.9Gy for left and right parotids respectively; the median of the mean larynx dose was 37.6Gy. The mean for theshifts were 1.29cm (range0.87-1.44) for x axis, y axis- 1.82 (-5.37 to 2.85),
z axis-1.67, (-0.68 to 8.01) and roll 0.45deg (-1.22-1.28). The median beamon time (overall and for oropharynx) was 403.5secs and treatment time was
25.74 mins.
Conclusions: All doses for PTV and constraints of OARs were achieved. The
systematic errors for shifts were calculated and were above the 3mm CTV to
PTV margins, reititerating the importance of daily image guidance. The beamon time and overall treatment time were comparable to other IG/IMRT capable
linear accelerators.

835 poster
FLAP RECONSTRUCTION AND POSTOPERATIVE IRRADIATION IN
LOCALLY ADVANCED HEAD-NECK CANCER: OUR MULTIDISCIPLINARY EXPERIENCE
C. L. Deantoni1 , A. Baio1 , D. Cavallini Francolini1 , S. Colombo1 , P. De
Vecchi1 , L. Squillace1 , P. Massaro1 , C. Plasmati1 , F. Cammarano1 , G.
Bertino2 , A. Occhini2 , M. Benazzo2 , C. Porta3 , F. Corbella1
1
I.R.C.C.S. P OLICLINICO S AN M ATTEO,, Struttura Complessa di Radioterapia Oncologica, Pavia, Italy
2
I.R.C.C.S. P OLICLINICO S AN M ATTEO,, Institute of Otolaryngology Head
Neck Surgery, Pavia, Italy
3
I.R.C.C.S. P OLICLINICO S AN M ATTEO,, Department of Oncolory, Pavia,
Italy
Purpose: The aim of this retrospective study was to evaluate the efficacy
and acute and late toxicity of postoperative irradiation in patients affected by
locally advanced head and neck cancer who underwent radical surgery withflap reconstruction.
Materials: From January 2003 to December 2009, 39 patients affectedby locally advanced head-neck cancer, treated with radical surgery withflap reconstruction, underwent 3D conformational radiotherapy. Thirty-four
were males and 5 were females with mean age of 60,3 years (range 4281 years). The cancer was placed in oral cavity in 18 patients (46,2%), in
oropharynx in 4 patients (10,3%), in hypopharynx in 12 patients (30,8%)
and in larynx in 5 patients (12,8%).All tumors were squamous, with different grading: G1 = 5,1%, G2 = 51,3%, G2-G3 = 12,8%, G3 = 30,8%.
At staging we found T1N0=2,6%, T1N2b=2,6%, T2N0=7,7%, T2N1=7,7%,
T2N2a=7,7%, T2N2b=7,7%, T2N2c=5,1%, T2N3=2,6%, T3N1=7,7%,
T3N2a=2,6%, T3N2b=10,2%, T3N2c=5,1%, T4aN0=7,7%; T4aN1=5,1%,
T4aN2a=2,6%, T4aN2b =10,2%, T4a N2c=5,2%.The flaps were removed
from radius (25,6%), pectoral (17,9%), forearm (12,8%), jejunum (10,3%),
fibula (7,7%), thigh (23,1%) and platisma (2,6%).All patients were treated on
surgical bed and bilateral cervical nodes (PTV II: 50-54 Gy). In 26 cases wedefined also a PTV I in case of "close"margins (60 Gy), on surgical bed if lips
were infiltrated or on nodal seat if there was capsulary breaking (66 Gy). The
dose was administered in fractions of 1,8-2 Gy for 5 days a week.
Results: At the end of treatment, all patients obtained completed remissionof disease (RC).Out of totality of cases we observed disease free survival(DFS): 74,4% with medium follow up of 24,6 months (range 0-63), primary
tumour relapse: 17,9% (medium time of 16 months), nodal relapse: 2,6%
(time of 10 months), distant metastases incidence: 5,1% (time of 14 months).
During treatment, G1-G2 mucositis, dermatitis, dysphagia, odynophagia, xerostomia, oedema and trismus were recorded but only three G3 events in 2
cases. All patients completed the treatment. No significant late toxicity wasobserved during the follow-up.None of the patients showed flap necrosis or
pain.
Conclusions: Few studies about flap reconstruction and postoperative irradiation are reported in literature.Our data show good results in terms of
disease-free survival rate and very limited acute and late toxicity, especiallyin irradiated flaps.
836 poster
FUNCTIONAL MR IMAGING IN PATIENTS WITH OROPHARYNGEALCANCER AND THE RELATION TO HPV.
M. Lambrecht1 , V. Vandecaveye2 , E. Van Limbergen3 , I. Roebben2 , F. De
Keyzer2 , R. Hermans2 , S. Nuyts1
1
L EUVENS K ANKER I NSTITUUT (LKI), U NIVERSITY H OSPITAL G ASTHUIS BERG , Radiation Oncology, Leuven, Belgium
2
U NIVERSITY H OSPITAL G ASTHUISBERG, Radiology, Leuven, Belgium
3
U NIVERSITY H OSPITAL G ASTHUISBERG, Experimental Radiotherapy,
Leuven, Belgium
Purpose: Recent publications have shown that the human papilloma virus(HPV) status is a strong and independent prognostic factor for survival inpatients with oropharyngeal cancer [1]. In this study we want to investigate whether findings on pretreatment diffusion weighted (DW-) and dynamic
contrast-enhanced (DCE-) magnetic resonance imaging (MRI) correlates with
the HPV status.
Materials: A total of 50 patients with biopsy-proven oropharyngeal cancer
have been included in this study. All patients were treated with definitive(chemo-)radiotherapy. Formalin paraffin embedded tumor biopsies were subjected to p16 immunohistochemistry. Subsequently DNA was tested for HPV
with the GP5+/6+ consensus primers set in a polymerase chain reaction(PCR). All patients underwent a pretreatment MRI with DW (6 b-values between 0 and 1000 s/mm) and DCE-MRI. All primary lesions were delineatedon both imaging modalities. The apparent diffusion coefficient (ADC) andtumoral perfusion were calculated using dedicated software. For the preliminary results an unpaired t-test was used to compare the pretreatment ADC
values and semi-quantitative DCE parameters (washin, cpeak and time topeak (TTP)) of the tumor between HPV + and HPV - tumors.
Results: So far 15 patients were analyzed on both HPV status and DWI.
Analysis of the pretreatment ADC values in these patients showed a signifi-

S 325

cant difference in pretreatment ADC value between HPV+ compared to HPVpatients (0,99 ± 0,16 x10-3 mm/s vs. 1,35 ± 0,28 x10-3 mm/s, p: 0,02 respectively). (Figure 1) Semiquantitative evaluation of DCE imaging in 14 ofthese patients demonstrated a tendency towards a lower wash-in value in the
HPV+ tumors (15.1 ± 4.8 /s vs 22.1 ± 8.5 /s, p: 0.1) .

Conclusions: In this small patient population, a significantly lower pretreatment ADC was found in HPV+ compared to HPV- tumors in patients withoropharyngeal cancer. For DCE-MRI, a tendency towards a lower washin was found in HPV+ compared to HPV- tumors. These preliminary findings suggest differences in cellularity and vascularization between HPV+
and HPV- tumors. Future analysis on the entire study population is required to confirm these findings and correlate the investigated functional MRIparameters as potential imaging biomarkers in head and neck cancer.
References: [1] Ang KK, Harris J, Wheeler R, et al. Human papillomavirus
and survival of patients. N Engl J Med 2010 363:24-35.
837 poster
HIGH-DOSEINTENSITY-MODULATEDRADIOTHERAPYSINONASAL TUMORS: 10-YEAR CLINICAL EXPERIENCE.
1
1
1
F. Duprez , I. Madani , L. Morbee , T. Boterberg1 , W. De Neve1
1

FOR

G HENT U NIVERSITY H OSPITAL, Radiotherapy Department, Ghent, Belgium

Purpose: To report long-term treatment outcome of intensity-modulated radiotherapy (IMRT) for sinonasal tumors.
Materials: Between 1998 and 2009, 130 patients with non-metastasizedsinonasal tumors were treated with IMRT to a median total dose of 70 Gy (n= 120) or 60-66 Gy (n = 10) in 2-Gy daily fractions. IMRT was post-operativein 101 patients. Since January 2006 cone-beam CT has been used for patient position verification. Most of the patients had adenocarcinoma (n = 82),
squamous cell carcinoma (n = 23) and esthesioneuroblastoma (n=10). Of 18
patients with recurrent tumors, 10 were reirradiated. T-stage was T1-2 (n =39), T3 (n = 21), T4a (n = 38) and T4b (n = 22). Esthesioneuroblastoma wasstaged as Kadish A, B and C in 1, 3 and 6 cases, respectively. Late toxicity
was scored from ≥ 6 months after IMRT.
Results: Median follow-up was 52, range 15-121 months. Nine patients did
not finish treatment due to toxicity (n = 1), complications after craniofacial resection (n = 1), intercurrent death (n = 1), refusal (n = 2), disease progression(n = 2) and newly diagnosed second primary metastasized cancer (n = 2). For
the whole patient cohort, 5-year local control (LC) was 59%. On multivariate
analysis LC was worse in patients with T4-tumors,with invasion of the cribriform plate and brain and who did not undergo surgery. Five-year overall (OS),disease-specific (DSS) and disease-free (DFS) survival were 52%, 64% and39%, respectively (Figure). On multivariate analysis invasion of the cribriform
plate and orbit and absence of surgery negatively affected OS. LC, OS, DFS
and DSS did not differ between primary vs. recurrent tumors (p = 0.3, 0.7,
0.3 and 0.8, respectively). Acute toxicity was evaluated in 128 patients. No
patients developed severe dry-eye syndrome during treatment. Nine patients
had other acute grade 3 ocular toxicity that did not translate into late grade
3 toxicity. Late toxicity was assessed in 86 patients. No radiation-induced
blindness was observed. The worst grade of ocular late toxicity was grade
3 in 11 patients, grade 2 in 31 patients, grade 1 in 33 patients and grade
0 in 11 patients. Late grade 3 tearing occurred in 10 patients. One patient
had grade 3 visual impairment due to radiation-induced ipsilateral vasculitis.
Other late grade 3-4 toxicity included brain necrosis (n = 5, reirradiation in1), grade 3 xerostomia (n = 2; reirradiation in 1), taste alteration (n = 7) andosteoradionecrosis of the ipsilateral maxilla (n = 1 after reirradiation).

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H EAD N ECK CANCER

H EAD N ECK CANCER
Results: All 5 cases received a mean dose to the gross tumor volume (GTV)of 70Gy. 2 year follow up showed an overall survival of 100% and 100%
complete response. All 5 patients received concurrent chemotherapy. Acuteside effects were grade 1 dysphagia, ageusia and mucositis, late side effects
noted only in 1 patient was sensorineural symptoms.
Conclusions: IG-IMRT for nasopharyngeal carcinoma in the Philippinesachieved better if not comparable outcomes compared with contemporaryseries reporting on IMRT of the nasopharyngeal carcinoma abroad. Online
CBCT reduces the radiation dose to normal critical structures and creates
possibility of escalating dose to the target.
840 poster
IMRT-SIB IN NASOPHARYNGEAL CANCER: QUALITY AND TOXICITY EVALUATION IN A MONOISTITUTIONAL EXPERIENCE
D. Russo1 , A. Papaleo1 , E. Cavalera1 , A. Leone1 , M. G. Natali2 , G.
Ronzino3 , A. Palumbo4 , C. Nuzzo5 , G. Pastore2 , M. Santantonio1
1
R ADIATION T HERAPY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
2
M EDICAL P HYSICS U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
3
O NCOLOGY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
4
OTORHINOLARYNGOIATRY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
5
R ADIOLOGY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy

Conclusions: Implementation of IMRT in treatment of sinonasal tumors allowed delivering high doses to the target and improved disease control atminimal toxicity, in particular ocular toxicity. None of our patients developed
severe dry-eye syndrome or radiation-induced blindness.
838 poster
ICE CREAM ADAPTED AS A NUTRITIONAL SUPPLEMENT IN
CANCER PATIENTS: IMPACT ON QUALITY OF LIFE
F. Casas1
1
H OSPITAL CL INIC, 2nd Radiation Therapy Department, Barcelona, Spain
Purpose: A prospective comparative study that assesses the impact of ice
cream adapted as a dietary supplement on the quality of life (QOL) of malnourished patients with cancer.
Materials: We present an exploratory prospective observational study comparing two patterns of nutrition: adapted ice cream and nutritional supplements. Patients were selected from two different hospitals from the same
Oncologic Institute. QOL was examined by Hospital Anxiety and Depression Scale (HADS) and QLQ of the European Organization for Research andTreatment of Cancer (EORTC QLQ C30). Nutrition was determined by PGSGA test.
Results: In HADS, significant differences were found at the end of the study
only in Group I, in anxiety (p = 0.023) and depression (p = 0.011). QLQ-C30
revealed statistically significant differences in baseline measures of global
dimension between the two groups (Group I: 40.64-56.36 CI; Group II: 25.7043.11 CI; p=0.017). Differences were also present in the social dimension(Groups I: 77.42-93.51 CI; Group II: 55.85-82.85 CI; p=0.039. Statisticallysignificant differences were observed between the two groups at the end of
the study on the global scale: Group I had 49.36-63.88 CI and Group II had
33.05-51.88 CI; p=0.016, and on the fatigue scale: Group I had 36.19-53.83
CI and Group II had mean = 65.87, CI 52.50-79.23 CI, p=0.007.
Conclusions: : The administration of ice cream would partly cover the social
aspect of food and improve QOL in malnourished cancer patients. These
results are encouraging and deserve further confirmation.

Purpose: To evaluate quality of dosimetric results and early toxicity pattern inpatients affected by Nasopharingeal Cancer, treated with Serial Tomotherapy
IMRT.
Materials: From November 2008 to October 2010, 11 patients (median age:
52ys, range:16-68ys) affected by Nasopharyngeal cancer received SIB-IMRT
using Serial Tomotherapy. Istopathology was squamous carcinoma Regaud
type in 9 pts and lymphoepitelioma Schminke type in 2 pts. TNM stage (6thedition) was IIB in 1 pt, III in 5 pts, IVA in 4 pts and IVB in 1 pt. Seven pts(63,6%) received 3 cycles of induction chemotherapy (5 CDDP/5FU, 1 TPF
and 1 CDDP/EPI). Ten pts (91%) received concomitant weekly CDDP. On CT
scan were defined PTV1 (primary and metastatic lymph nodes), PTV2 (lymphnodes at high risk of subclinical invasion) and PTV3 (lymphnodes at low
risk of subclinical invasion), spinal cord, brainstem, parotid glands and lens.
Prescription doses were 69.9 Gy in 2.33 Gy fractions to PTV1, 60 Gy in 2
Gy fractions to PTV2 and 54 Gy in 1.8 Gy fractions to PTV3 (1,2). Overall
treatment time was 6 weeks. In every IMRT plan, for each target we calculated Homogeneity Index and Conformity Index.Early toxicity was classified
according to RTOG Criteria. Every patient underwent FLSD 30-45 days after
treatment completion.
Results: HI and CI values are summed in table 1; their interpretation was
performed according to RTOG criteria. Mean dose to omolateral and controlateral parotid was 35,5 Gy (range 28-49 Gy) and 34,2 Gy (range 27-44
Gy) respectively. Maximum dose to spinal cord and brainstem was 40,2 Gy(range 28-49 Gy) and 47,7 Gy (range 38-60 Gy) respectively. Maximum doseto lenses was 4,38 Gy (range 2,5-8 Gy).Side effects were dysphagia G2-G3
in 5 pts (54,5%), skin toxicity G2-G3 in 6 pts (54,5%), and mucositis G2 in 2
pts (18,2%). All patients continued oral nutrition. Salivary toxicity was always(G1-G2). One patient died during treatment, after 29 radiation fractions.FLSD
after one month showed RC in 8 pts and RP in 2 pts. Nine patients are actually alive without evident disease. One patient showed progression disease
after six months.

839 poster
IMAGE-GUIDED RADIOTHERAPY FOR NASOPHARYGEAL CARCINOMA IN THE PHILIPPINES: FIRST CLINICAL EXPERIENCE
M. Cruz1
1
S ACRED H EART M EDICAL C ENTER C ANCER I NSTITUTE, 2nd Radiotherapy
Department, Batangas, Philippines
Purpose: The advent of new level of treatment precision has brought requirements for image confirmation of the targetsduring treatment, automatedimage guidance of the radiotherapydelivery and reduction of side effects. Its
promising technology aim to improve the accuracy in the treatment of headand neck malignancies especially in developing countries. This is to reporta single institutional experience with the use of image guided (IG)- based intensity modulated radiotherapy (IMRT) for nasopharyngeal carcinoma in thePhilippines.
Materials: Elekta synergy E1594 system which integrates a X-ray volumetricimager (XVI), was used to treat the first 5 cases of nasopharyngeal carcinoma. 7 coplanar beams were generated via forward planning using Precise
treatment planning system. Image guide registration using cone beam computed tomography (CBCT) were done on 1st 5 days of radiation therapy thentwice weekly until end of treatment. Concurrent chemotherapy was recommended in all patients and radiation therapy was given for 35 sessions, 5
fractions per week.

Conclusions: Corvus® inverse planning allows acceptable dosimetric resultsand HI and CI values are compliant with IMRT protocols. Worse toxicity pattern were observed in patient with greater treatment volumes. Patient deadduring treatment (stage T4bN2cM0) received induction TPF and concomitant
RT-CDDP, which is probably a more toxic schedule; high dose volumes inthis patient were very large (V70: 444cc, V60: 440cc, V54: 51cc). Althoughdemostration of altered fractionation’s clinical advantage needs longer followup, we can suppose that it doesn’t induce severe early toxicity. LRR and OS
in this series are encouraging, but demostration of correspondance between
dosimetric advantages and improvement in terms of outcome and late effects
needs a greater patients’ number and a longer follow-up.

841 poster
INDUCTION TPF IN LOCALLY ADVANCED HEAD AND NECK CANCER IN THE COMMUNITY SETTING: OUTCOMES AND TOXICITIES
D. Cagney1 , I. Collins2 , C. Cagney1 , J. Kinsella3 , C. Timon3 , L. Stassen4 ,K. O’Byrne2 , D. O’MAHONY2 , D. Hollywood5 , S. Brennan1
S T J AMES U NIVERSITY H OSPITAL, 1st Clinical Oncology Department,
Dublin, Ireland Republic of2
S T J AMES U NIVERSITY H OSPITAL, Department of Medical Oncology,
Dublin, Ireland Republic of3
S T J AMES U NIVERSITY H OSPITAL, Department of ENT, Dublin, Ireland
Republic of4
S T J AMES U NIVERSITY H OSPITAL, Department of Maxillofacial Surgery,
Dublin, Ireland Republic of
5
T RINITY C OLLEGE D UBLIN, 1st Clinical Oncology Department, Dublin,
Ireland Republic of1

Purpose: Evaluate our institutions use of induction TPF in locally advanced
HNSCC in the community setting, and to assess response rates, toxicities
and outcomes of treatment. Assess whether our data is comparable to highly
selected trial populations
Materials: A retrospective analysis was performed on patients receiving induction TPF over a 4 year period. Induction chemotherapy (IC) consisted of
docetaxel 75 mg/m2 & cisplatin 100 mg/m2 Day 1 & 5-FU 1000 mg/m2 on
Days 1-5 three weekly. Radiotherapy(RT) was given at 70 Gy (2 Gy per day,7 weeks) with concomitant cisplatin 40 mg/m2 /carboplatin AUC 1.5.
Results: 18 patients were treated with induction TPF. Four patients had
been treated with primary surgical intervention & therefore salvage treatment
was instituted. Fourteen patients were treated with induction TPF followed
by definitive RT. The median age was 52 years. Eighty-six percent of patients had an ECOG of 0/1. Seventy-nine percent were stage 4 diseasealthough none had distant metastasis. Twenty-one percent were stage 3.
The major grade 3/4 toxicities, (CTCAE v3) associated with chemotherapy
were neutropenia(57%), mucositis(36%), nausea(29%), ICU admissions with
ARF(14%), and a chemotherapy related death(7%).Chemotherapy response
was excellent with 86% (12/14) patients achieving a PR. One patient developed progressive disease and went on to receive palliative radiotherapy. One
patient died during chemotherapy. Twelve patients went on to receive radical
CT-RT, of whom 11 received concomitant chemotherapy. The major grade 3/4
toxicities associated with CT-RT were dermatitis(42%), xerostomia(33%), mucositis(25%), neutropenia(25%) & dysphagia(8%).Of the 14 patients treatedwith radical intent in this study 9 patients are alive and are disease free with a
median follow up of 20 months. One patient died due to induction chemotherapy, two patients died due to distant metastatic disease, while two patientsare alive but have loco-regional recurrence.
Conclusions: Our data is comparable from a toxicity point of view to randomized control trials where induction TPF is administered. Despite the advanced
stage of our patients the response rates are encouraging with 64% alive anddisease free. We would emphasize the importance of careful patient selection
when it comes to administering induction TPF.
842 poster
INTENSIFICATION TREATMENT BY CONFORMAL STEREOTACTIC
BOOST AND TEMOZOLOMIDE IN NAÏVE HIGH GRADE GLIOMAS:NEUROCOGNITIVE EVALUATION AND LONG TERM RESULTS
S. Manfrida1 , G. Chiloiro1 , G. Apicella2 , S. Chiesa1 , G. R. D’ Agostino1 , L.
De Filippo1 , F. Alba1 , M. A. Gambacorta1 , C. G. Rinaldi1 , V. Valentini1 , C.
Anile3 , M. Balducci1
1
C ATHOLIC U NIVERSITY - U NIVERSITY H OSPITAL "A.G EMELLI ", Radiotherapy Department, Roma, Italy
2
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Radiotherapy Department, Novara, Italy
3
C ATHOLIC U NIVERSITY - U NIVERSITY H OSPITAL "A.G EMELLI ", Neurological Surgery, Roma, Italy
Purpose: The aim of this phase II study was to evaluate the late neurotoxicity by Mini-Mental-State-Examination (MMSE) in patients affected by High
Grade Glioma (HGG- III and IV grade WHO) treated by 3D-Conformal Radiation Therapy (3D-CRT) plus Fractionated Stereotactic Conformal Radiation
Therapy (FSCRT) until 69.4Gy and Temozolomide (TMZ). The outcomes interms of disease free survival (DFS) and overall survival (OS) have been
analysed
Materials: Patients (≥18 yrs) with CTV≤8 were enrolled. Two different
schedules of radiotherapy have been used to obtain the total dose prescribed(69,4Gy).Total dose of 3D-CRT was 50.4Gy in case of concomitant plus sequential FSCRT boost or 59.4Gy in case of sequential FSCRT boost. These 2schedules were selected by the CTV1 diameter (≤6 cm or >6 cm and ≤8cm).
Concomitant TMZ (75mg/m2) was administered during the first 2 or 4 weeks
of radiotherapy related to FSCRT modality. Adjuvant TMZ (150-200mg/m2)
was administered for at least 6 cycles. Acute toxicity was evaluated according
to RTOG score. The neurocognitive functions were evaluated in patients with
an OS>14,6 months (median OS of Stupp’s study) according to MMSE (total
score-TS =30): space-time orientation (TS=10), short-term memory (TS=3),

S 327

attention and ability to calculate (TS=5), memory (TS=3), language (TS=8)
and construction skills (TS=1).
Results: We enrolled 43 patients (38 Glioblastoma-GBM): 27 (63%) maleand 16 (37%) female. Median age was 53 years (range 25-72). With a medianfollow up of 72 months (range 23-81), 12 patients were alive with a medianDFS of 10 months (GBM: 10 months) and median OS of 29 months (GBM:
26 months). Two-years DFS was 32,6% (GBM: 26,3%) and OS was 55,8%(GBM: 50%). The acute neurological toxicity G1/2 and G3 were 12% and 3%,
respectively. Late neurological toxicity included 2 cases of radio-necrosis ofhistologically-proven radio-necrosis (at 14 and 24 months). Neurocognivefunctions were evaluated in 11 out of 33 elegible patients. With a mean TSof 27,9, we observed a complete preservation of short-term memory andlanguage functions in all patients; mean score of space-time orientation was
9,6 (4 patients obtained 9/10); the attention and calculation skills were themore damaged function (mean TS of 4,1), but it may be correlated to thescolarity level; mean memory score was 2,2 and only 1 patient presented
difficulties in construction skills.
Conclusions: FSCRT boost associated to 3D-CRT and TMZ is well tolerated
with a good preservation of neurocognitive functions; moreover it seems toincrease outcomes in patients with HGG.
843 poster
IS SAFE DOSE ESCALATION POSSIBLE IN OROPHARNGEAL SCC:RESULTS OF THE VORTIGERN STUDY
S. Chatterjee12 , J. Frew2 , J. Wilsdon3 , J. Mott2 , P. Stevenson2 , N. Willis2 ,R. maxwell4 , C. Kelly2
TATA M EDICAL C ENTER, Kolkata, India
2
N ORTHERN C ENTRE FOR C ANCER T REATMENT, Newcastle upon Tyne,
United Kingdom
3
N ORTHERN C ENTRE FOR C ANCER T REATMENT, Department of Radiation
Oncology, Newcastle upon Tyne, United Kingdom
4
N EWCASTLE U NIVERSITY, Newcastle upon Tyne, United Kingdom

1

Purpose: One of the challenges for escalating dose to the oropharynx includes high likelihood of dysphagia and trismus. Vortigern study explores thepossibility of safe dose escalation in the oropharynx.
Materials: To get baseline data on doses received by the mastication apparatus (pterygoids (P), masseter(M), temporalis(T) and temporomandibular
joints (TMJ)), 15 standard dose oropharynx plans (65Gy in 30 fractions): 5
with forward planned 2 phase (F2P), 5 forward planned one phase (F1P),
and 5 helical tomotherapy (HT) with oropharyngeal cancers were compared.
Following this, after informed consent, a feasibility dose escalation (9% escalation, α/β =10, dose 67.2Gy in 28 fractions) was explored using HT within
the Vortigern study. Dose escalation (DE) was planned on a FDG PET/CT
avid (40% of maximum tumour intensity) GTV plus 2mm target, a standard
dose (63Gy in 28 fractions equivalent to 65Gy in 30 fractions) to high risk PTV
and 56Gy in 28 fractions was prescribed to the prophylactic PTV.
Results: Mean pterygoid doses with F2P versus F1P versus HT were
57.82Gy, 58.22Gy, 52.95Gy; mean masseter doses were 54.73Gy, 53.35Gy,
39.31Gy; mean temporalis doses were 20.52Gy, 34.16Gy, 31.07Gy and TMJ
doses were 47.99Gy, 35.1Gy and 33.02Gy respectively. Safe dose escalation plans were possible with median prescribed escalated tumour doses
being achieved. OAR doses were within limits of tolerance (parotids mean
<30 Gy and was comparable to the standard dose plan; constrictors meandoses were 62Gy with the escalated GTV volume encompassing part of themuscles). Mean Temporalis, masseter and pterygoids recorded lower doses
well within limits of their tolerance.
Conclusions: Dose escalation in the oropharynx tumour subvolumes was
possible with dose to the muscles of mastication as in the non dose escalated
HT plans and tolerance dose to swallowing structures were achieved.
844 poster
LOCALIZATION AND QUANTIFICATION OF DELIVERED DOSE TO
THE SPINAL CORD: IS THE DOSE TO THE SPINAL CORD STILL AN
ISSUE IN DAILY IGRT?
M. N. Duma1 , T. Schuster2 , L. S. Fromm3 , N. Aswathanarayana3 , M.
Molls1 , H. Geinitz1
1
K LINIKUM RECHTS DER I SAR , TU M ÜNCHEN, Department of Radiation
Oncology, München, Germany
2
K LINIKUM RECHTS DER I SAR , TU M ÜNCHEN, Department of Statistics,
München, Germany
3
M EDICAL FACULTY, T ECHNISCHE U NIVERSITÄT M ÜNCHEN, München,
Germany
Purpose: Several preclinical data indicate dose differences in spinal cordradiation-sensitivity. The ED50 that can be applied to small regions decreases
significantly if the adjacent cervical spine is irradiated with a low dose. Further, some data are available on differences in radiation-sensitivity of the anterior spinal cord when compared to the posterior spinal cord if the whole spinal
cord is irradiated with the same dose. No data are available about the localization of actual delivered doses to the spinal cord in humans. The purpose

S 328H EAD N ECK CANCER

H EAD N ECK CANCER

of the study was to localize and quantify the delivered dose to the cervicalspinal cord (SC) during head and neck cancer (H&N) helical TomoTherapy(HT).
Materials: 20 H&N patients treated with bilateral nodal irradiation (including
the supraclavicular lymph nodes) were analyzed. Daily pretreatment megavoltage CTs (MVCTs) were performed for each patient on each treatment
day for setup purposes (image-guided radiotherapy - IGRT). Every registration was corrected by staff members before treatment. On every second
MVCT the SC was recontoured and the delivered dose for the given treatment day was recalculated. The Dmax on the planning CT scan (PCT-Dmax)
and the actual delivered Dmax (a-Dmax) were analyzed. When the a-Dmax
was higher that the PCT-Dmax we assessed: 1. in which CT slices the spinal
cord received a higher dose than the PCT-Dmax;2. which quadrants (anterior
right, anterior left, posterior right, posterior left) of the spinal cord received ahigher dose than the PCT-Dmax;3. the volumes of the spinal cord that received a higher dose than the PCT-Dmaxand compared this data to the dataof the PCT.
Results: 51% of the analyzed fractions had a higher a-Dmax than the PCTDmax. For these fractions, the median increase of Dmax/ fraction comparedwith the PCT-Dmax was +3% (range 0% to +44%). For all patients the increase involved mainly the two anterior quadrants: anterior right and anterior
left. The quadrants which received a higher dose than the expected PCTDmax did not overlap with the quadrants where the PCT-Dmax was located.
The quadrants and CT slices that were affected by an increase in dose were
for the majority of fractions similar from MVCT to MVCT for the same patient (Fig. 1. a and b). The Dmax changes can be explained by the soft
tissue shrinkage that all H&N patients undergo during treatment, as well as
by the different setup of the patient within the mask. Even in patients with atight mask a different curvature of the cervical spinal cord was noted on the
MVCT. These "new" curvatures were daily reproducible on the MVCTs andwere probably due to patients’ adjustment to the treatment procedure (e.g.
relaxing).Fig. 1 a. Example of analyzed quadrants on MVCT in slice 19 for
fraction no. 14. The darker area anterior right and posterior right represents
the isodose of the delivered dose that was higher than the PCT-Dmax. Fig. 1
b. Overall distribution of doses higher than the PCT-Dmax in all quadrants forthe analyzed fractions. The PCT-Dmax was localized for this patient on theslices 19 and 20, right-sided (grey underlined in the table).

age 18-80 years; RPA classes V-VI; estimated survival 3 months; normal
haematological, renal, hepatic, cardiac and respiratory functions. Gross
Tumor Volume (GTV) was defined as the surgical bed with gross residual
contrast-enhancing tissue on magnetic resonance imaging. The Clinical Target Volume (CTV) was defined as the GTV with a 30 mm margin to include
any potential subclinical tumor. The Planning Target Volume (PTV) was defined as CTV + 5 mm, due to set-up uncertainties. Hypofractionated 3D conformal radiotherapy (3D-CRT) was delivered on GTV (total dose: 30 Gy in
fractions of 3 Gy/day) with concomitant and adjuvant (1 cycle) temozolomide(TMZ). From second to fifth cycle of adjuvant TMZ (200 mg/m2 ), if neither
progression disease was demonstrated on magnetic resonance imaging, nor
unacceptable toxicities were recorded, LD-FRT was associated (2 daily fractions of 0.40 Gy, over 5 days, q 28). Primary endpoint of the study was theevaluation of toxicity and safety of this schedula (RTOG criteria). Clinical response (RECIST criteria), progression free survival (PFS) and overall survival(OS) were also evaluated.
Results: From June 2008 to October 2010 15 patients with a newly diagnosis of GBM were enrolled in this study. Eight patients underwent incomplete
surgical resection and 7 patients received only biopsy. The median total doseof LD-FRT delivered was 1040 cGy (range 320 1920). Up to this date 11
patients are evaluable. Grade 12 haematological toxicity was observed in 18% of patients, grade 34 was observed in 9 % of patients, mainly represented
by leukopenia and thrombocytopenia; however no neurological acute and late
toxicity were observed. No treatment related death occurred. Four patients(36%) had a partial response (PR), while 2 patients (18%) had a stable disease (SD), lasting more than 8 weeks (Clinical Benefit 54%). At a medianfollow-up of 9 months (range 2 22) median PFS was 5 months and median
OS was 9 months, with a survival rate at 1 year of 30%.
Conclusions: The results of the study demonstrated that LD-FRT with concurrent chemotherapy, after hypofractionated 3D-CRT plus Temozolomide, isa well tolerated treatment with a low toxicity profile. This data seem to be
encouraging and suggest the prosecution of the analysis.
846 poster
LOW-DOSE FRACTIONATED RADIOTHERAPY PLUS CHEMOTHERAPY IN PATIENTS AFFECTED BY GLIOBLASTOMA MULTIFORME
IN FIRST RECURRENT OR PROGRESSIVE DISEASE: INTERIMANALYSIS.
G. R. D’ Agostino1 , S. Chiesa1 , S. Manfrida1 , B. Diletto1 , G. Mantini1 , V.
Frascino1 , F. Miccichè1 , R. Autorino1 , V. Valentini1 , F. De Rose1 , C. Anile2 ,M. Balducci1
1
C ATHOLIC U NIVERSITY - U NIVERSITY H OSPITAL "A.G EMELLI ", Radiotherapy Department, Roma, Italy
2
C ATHOLIC U NIVERSITY - U NIVERSITY H OSPITAL "A.G EMELLI ", Neurological Surgery, Roma, Italy

Conclusions: There is only a small difference in the delivered Dmax to thespinal cord if daily IGRT is performed. A higher dose than the planning CT Dmax was observed in approximately half of the fractions and affected mostly
the anterior half of the spinal cord. The localization and magnitude of increasein Dmax cannot be predicted by analyzing the PCT. The quadrants and CT
slices that receive a higher dose than the PCT-Dmax are very similar fromfraction to fraction. Thus, in radiotherapy plans that go as high as the known
tolerance doses of the spinal cord a recalculation of dose on the MVCT canbe useful in order to predict the localization and magnitude of the changes in
Dmax. Preclinical studies should focus on differences in anterior vs. posteriorcervical spinal cord irradiation.
845 poster
LOW DOSE FRACTIONATED RADIOTHERAPY AND TEMOZOLOMIDE IN NEWLY DIAGNOSED GLIOBLASTOMA MULTIFORME:PRELIMINARY RESULTS OF A PILOT STUDY
S. Chiesa1 , B. Diletto1 , G. R. D’ Agostino1 , S. Manfrida1 , G. Mantini1 , L. De
Filippo1 , V. Frascino1 , S. Fersino1 , A. Mangiola2 , C. Anile2 , V. Valentini1 , M.
Balducci1
1
C ATHOLIC U NIVERSITY OF S ACRED H EART, Department of Bioimaging
and Radiologic Science, Radiotherapy Institute, Rome, Italy
2
C ATHOLIC U NIVERSITY OF S ACRED H EART, Department of Neurosurgery,
Rome, Italy
Purpose: Glioblastoma Multiforme (GBM) is the brain tumor with the worst
prognosis, especially for patients with gross residual tumor after surgery (RPA
classes V and VI). In vitro studies demonstrated the hyper-radiosensitivity ofhuman malignant glioma cell lines to low radiation doses, moreover preclinical studies hypothesized a synergism between low doses fractionated radiotherapy (LD-FRT) and chemotherapy. Therefore we planned a pilot study todefine the feasibility and the efficacy of this approach in na GBM RPA classes
V-VI.
Materials: Patients enrolled in the study had the following characteristics:
histological diagnosis of GBM, based on minimal surgical resection or biopsy;

Purpose: Glioblastoma Multiforme (GBM) is characterized by a dismal outcome and patients with recurrent or progressive disease have, obviously, a
far worse prognosis. An hyper-radiosensivity to low radiation doses of human malignant glioma cell lines has been demonstrated by in vitro studies
while preclinical studies have shown a chemo-sensitization induced by low
doses fractionated radiotherapy (LD-FRT). We present data about a prospective analysis performed in patients with recurrent and/or progressive GBM,
treated by concurrent chemotherapy and LD-FRT, investigating the feasibility
and efficacy of this approach.
Materials: Patients with a radiological diagnosis of recurrent or progressive
GBM were enrolled. All patients were previously treated by surgical resection followed by radio-chemotherapy according to Stupp’s schedule modified.
LD-FRT were performed on gross tumor volume + 3 cm margins, associated with chemotherapy according to two different schedules related to timeof progression: patients presenting progression during Temozolomide (TMZ)
therapy received 30 cGy twice a day on days 1-2,8-9,15-16, q42, concurrently with cisplatin (30 mg/m2 on days 1, 8, 15) and fotemustine (40 mg/m2 ,on days 2, 9, 16); patients presenting recurrence after 4-6 months from TMZ
received 40 cGy twice a day, over consecutive 5 days, q 28, concurrently withTMZ (150/200 mg/m2 ). Toxicity and safety of these schedules (RTOG criteria), Clinical response (RECIST criteria), Progression Free Survival (PFS)and Overall Survival (OS) were evaluated.
Results: Seventeen patients were enrolled between February 2008 and May
2010. Median age was 65 years (range 21-71). The median total dose of
LD-FRT delivered was 720 cGy (range 240 1160 cGy). LD-FRT were administered with TMZ in 59% of cases and with cisplatin and fotemustine in 41% of
patients. A grade 1-2 hematologic toxicity was observed in 35.2% of patients,a grade 3-4 toxicity, mainly leucopenia, was experienced by 6% of patients;
no cases of neurological toxicities, nor treatment related death occurred. One
patient (6 %) had a partial response (PR), while 3 patients (17.6%) experienced a stable disease (SD) for at least 8 weeks (Clinical Benefit 23.6%).
With a median follow-up of 40 months from the diagnosis of primary disease(range 21 - 76), the median PFS was 3 months, while the PFS at 6 and 12
months were 22% and 0% respectively. The median OS was 7 months, witha survival rate at 6 months of 69% and a 1-year OS of 16%.
Conclusions: Concurrent LD-FRT and chemotherapy was well tolerated.
These data seems to be encouraging and warrant the start-up of a phase
II study.

847 poster
ONCOLOGICAL OUTCOME IN ADVANCED LARYNGEAL CANCERS
TREATED WITH DIFFERENT MODALITIES IN A SINGLE INSTITUTION. A RETROSPECTIVE ANALYSIS ON 65 CASES.
F. Micciche1 , F. Bussu2 , N. Dinapoli1 , R. Autorino3 , G. Mantini1 , P.
Bonomo1 , M. Rigante1 , T. tartaglione3 , J. Galli3 , G. Almadori4 , P. Gaetano5 ,V. Valentini1
1
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Roma, Italy
2
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Campobasso, Italy
3
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Roma, Italy
4
UCSC, Roma , Italy
5
C ATHOLIC U NIVERSITY, Rome, Italy
Purpose: Treatment of laryngeal SCC has been predominantly surgical for
decades, but in the last 20 years non surgical modalities (radiotherapy), withthe aim of organ preservation, became predominant also among advanced
stages. Retrospectively evaluating our series of stage III and IV LSCCs, we
compared the 2 main therapeutic modalities.
Materials: Medical records of 65 consecutive advanced LSCC patients, from
November 2005 to January 2009, were reviewed.
Results: Among irradiated patients 2-year organ preservation was 86% for
cT2, 43% for cT3, 17% for cT4a (p=0.037 at Wilcoxon test). As for survival,
the only significant differences between surgery and radiotherapy were detected among cT4a (p=0.03 at Wilcoxon test), in favour of surgery.
Conclusions: The present results confirm the surgical recommendation
for cT4a LSCCs. On the other side, for T<4, our results confirm that radiochemotherapy warrants a similar survival than total laryngectomy, allowing
to preserve the larynx in a relevant number of cases.

S 329

event appears to be directly related to overexpression factor receptor (EGFR)
and its signaling pathways. Knowledge of this fact can help establish risk
subgroups with the intention of individualized therapies.Our objectives in thisstudy were to analyze receptor overexpression of epidermal growth factor(EGFR) in head and neck tumors. To evaluate the response to radiotherapy (in terms of locoregional relapse) and overexpression of EGFR. Identify
groups of high-risk patients may benefit from more aggressive therapy or included in studies with targeted therapies to target the EGFR or its signaling
pathways
Materials: We analyzed 67 patients diagnosed and treated with radiotherapy and chemotherapy of head and neck tumours. Four main locations: oralcavity, larynx, hypo pharynx, oropharynx. The expression of EGFR was determined by immunohistochemistry with the EGFR monoclonal Ab (Dako Cytomation). Cuts were obtained from 5 microns selected paraffin blocks, weredeparaffinized and rehydrated. Positive and negative controls were included.
Three types of analysis were conducted and graded: INTENSITY (I): negative, weak, moderate, intense; Distribution of immunostaining (D): negative,
incomplete membrane, complete membrane-incomplete membrane plus citoplasmic, complete membrane plus citoplasmic, citoplasmic; and Percentage
of stained cells (P): negative, <10%, 10-50%, >50%. Locoregional relapse
was objectified with otolaryngology examination and imaging (CT). Survival
was estimated from the end of radiotherapy.
Results: Mean follow up was 77 months. EGFR positive samples were 49(72%). Mean survival: 34 months. 24 patients still alive (36%). Locoregional
recurrence was tested in 29 patients (43%). Average time of LRR was 8
months. Analyzing the intensity of staining, With a follow up of 28 months,
intensity negative: 88.5% free of LRR, and intensity positive patients 46%
free of LRR (p=0.001)

848 poster
OPTIMUM FRACTIONATION – DEPENDS ON TUMOUR PROLIFERATION
J. Fowler12
1
U NIVERSITY OF W ISCONSIN , M ADISON, Madison WI, USA
2
G RAY I NSTITUTE FOR R ADIATION O NCOLOGY & B IOLOGY, U NIVERSITY OF
OXFORD, Oxford, United Kingdom
Purpose: There is no good reason to avoid the best possible radiation-onlyschedules no matter what adjunctive chemical or biological measures are
considered too. To understand how the limits & advantages of multifractionation radiotherapy really work, it is necessary to model both acute and latetolerance constraints, which was not possible until 2002-3 (Drr, Denham et al& Fowler, Harari et al.) Tumour proliferation rate first determines what is thealpha/beta ratio of the tumour. This decides strategy. Then for Head & Neck
Radiotherapy, kinetic considerations determine tactics.
Materials: Radiation scheduling is driven by differences in repopulation between tumour (starts at Tk = 2-5 wks) and acute (mucosal) normal tissue,(starts at Tk = 7d for mucosa, clinical data). Calculations were done of every
tolerated fraction size for Late Damage =70Gy EQD2/3Gy, & minimum overall
time for Acute Damage = 51 Gy EQD2/10Gy ; from 1F x17.3 Gy in 1 day to
115 F x 0.8 Gy in 23 (or 12 weeks @ 2F/d). Other assumptions were a/b =10 Gy for tumour and mucosa, and cell doubling time = 3d in tumours & = 2.5
d in mucosa. It was the difference in Tk’s that had the strongest effect.
Results: Optimum tumour cell kill was found for 20 fractions at 5F/wk (+/- 2Gy
EQD range =16 25F) but at 63 fractions at 10F/wk (range 47-75F). The maximum tumour doses for 2F/d were 2-5 Gy EQD higher than the maximum for
1F/d, these advantages becoming greater if Tp in tumours was slower. Only if
the Tp in tumours was as short as ~2d did results for1F/d approach those for
2F/d, using traditional Manchester-type 16F x 3.41Gy/ 21d hypofractionation.
To continue fractionated RT until the start of tumour repopulation (Tk) could
give an obvious gain, by permitting more and smaller fractions which always
allowed higher BEDs.
Conclusions: More attention should be given to finding individual tumour repopulation factors part-way through multifraction treatments, including seeking correlations with pre-treatment measurements of Tpot.

Conclusions: The rate of locoregional control and OS with RT+/-CT in advanced tumors of head and neck in our environment is consistent with previous reports. LRR remains the major cause of failure and death. Thereis positive correlation between EGFR (IH-intensity) and Local and Regional
Recurrence p=0,001. The systematic study of EGFR overexpression with immunohistochemical techniques in advanced head and neck tumors can help
select groups of patients to more aggressive and individualized treatment including non-conventional radiation therapy regimens and therapies aimed atother targets
850 poster
P16 IMMUNOHISTOCHEMISTRY AND HPV-PCR FOR RESPONSE
PREDICTION AFTER RADIOTHERAPY IN HNSCC
S. Nuyts1 , E. Van Limbergen2 , R. Dok1 , E. Hauben3
1

L EUVENS K ANKER I NSTITUUT (LKI), U NIVERSITY H OSPITAL G ASTHUIS -BERG , Department of Radiation Oncology, Leuven, Belgium

2

U NIVERSITY H OSPITAL G ASTHUISBERG, Department of Radiation
Oncology, Leuven, Belgium
L EUVENS K ANKER I NSTITUUT (LKI), U NIVERSITY H OSPITAL G ASTHUIS BERG , Pathology, Leuven, Belgium

3849 poster
OVEREXPRESSION OF EPIDERMAL GROWTH FACTOR RECEPTOR, LOCOREGIONAL RECURRENCE AND OVERALL SURVIVAL IN
HEAD AND NECK CANCER AFTER RADIOTHERAPY
M. Soler Tortosa1 , J. L. Monroy Anton1 , M. Lopez-Munoz1 , A. V. Navarro
Bergadá1 , M. A. Estornell Gualde1 , C. Gaspar Martinez1 , L. Morell
Quadreny1
1
H OSPITAL U NIVERSITARIO DE LA R IBERA, Department of Radiation
Oncology, Alzira, Spain
Purpose: In the treatment of head and neck cancer with radiotherapy, locoregional recurrence (LRR) is the dominant form of death. This adverse

Purpose: Recently, it has become clear that a subgroup of head and necksquamous cell carcinoma’s (HNSCC’s) related to human papilloma virus(HPV) responds far better to radiotherapy than the classical smoking andalcohol related HNSCC’s. As a result from the expression of the HPV viralprotein E7, p16 expression is strongly upregulated, in such a way that it canbe used as a biomarker for HPV related tumors. In this study we try to determine the role of p16 expression for response prediction after radiotherapy,
and its relation to HPV status.
Materials: Some 100 paraffin embedded [FFPE] tumor samples from patients irradiated for an oropharyngeal carcinoma at the Leuven University
hospital between 2001 and 2007 were subjected to p16 immunohistochemistry. Samples were scored for p16 staining as strong (when more than 25%

S 330H EAD N ECK CANCER

H EAD N ECK CANCER

of cancer cells had at least moderate immunoreactivity), as moderate (when10-25% of cancer cells had at least weak p16 immunoreactivity) or as negative (when less than 10% of cancer cells had p16 immunoreactivity).To investigate the relation of p16 immunoreactivity and HPV, DNA was extracted fromthe FFPE tumor samples. HPV status was determined with the GP5+/6+ consensus primers set in a PCR reaction. The Kaplan-Meier method was used
for survival analysis.
Results: Sixty-four samples have been evaluated at this moment. Respectively 21, 17, and 26 patients had negative, moderate and strong p16 stainingof their tumors. A dose response curve for p16 staining intensity and locoregional-control rate with 28%, 70% and 88% at 5 years (p=0.01) was seen
(fig1a). Additional tissue for HPV testing in the p16 positive staining groups
was available from 20 patients. In the moderate staining group only one patient in nine (11%) had a positive HPV PCR in contrast to the strong p16
staining group where eight on eleven (73%) patients had a positive PCR.
When we compared locoregional tumor control in patients with a positive p16
staining (moderate or strong) to patients with a negative p16 staining we sawthat the p16 positive group still had the better locoregional control even when
all patients with a positive HPV-PCR were excluded from the p16 positive
group (p=0.04) (fig1B).

Conclusions: The estimated prevalence of HPV related oropharyngeal carcinoma is 30% in our patient population (Leuven, Flanders, Belgium). In accordance to the literature HPV related tumors tend to have predominantly
strong p16 staining. Additionally, there seems to be a second group of tumors
with moderate p16 staining that tends to be HPV negative. The stronger the
p16 staining the better the locoregional control after radiotherapy (p=0.01).
Tumors with positive p16 staining have better locoregional control after radiotherapy even when they are HPV negative (p=0.04). All taken together, p16
may be a better marker than HPV status when it comes to response prediction after radiotherapy. Multivariate analysis will be performed on the entire
study population.
851 poster
PATTERN OF DISTANT METASTASES FOR HPV-RELATED OROPHARYNGEAL CANCER TREATED WITH RADIOTHERAPY
S. H. (. Huang1 , B. Perez-Ordonez2 , F. F. Liu1 , J. Waldron3 , J. Irish4 , L.
Siu5 , J. Kim1 , I. Weinreb2 , P. Gullane4 , B. O’Sullivan3
1
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO,
Department of Radiation Oncology, Toronto, Canada
2
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO,
Pathology, Toronto, Canada
3
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO,
Department of Radiotherapy Oncology, Toronto, Canada
4
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO,
Department of Surgical Oncology, Toronto, Canada
5
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO, Medical
Oncology, Toronto, Canada
Purpose: To report unusual pattern of distant metastases (DM) observed in
HPV-related oropharyngeal carcinoma (OPC) treated with radical radiotherapy (RT).
Materials: A retrospective cohort study was conducted for all newly diagnosed OPC cases treated with RT between 7/1/2003~4/30/2009. HPV positivity was determined by p16 immuno-staining in tumors. The frequency andpattern of distant metastases (DM) were compared between the HPV positive[HPV(+)] and HPV negative [HPV(-)] cohorts.
Results: HPV status was evaluated in 318 of 613 (52%) consecutive OPC
cases, revealing 236 HPV(+) and 82 HPV(-). With a median follow-up of 3.3
years, 36 DMs were identified, including 24 (10%) in the HPV(+) and 12 (15%)
in the HPV(-) cohorts. There was no difference in the overall incidence of DM
between HPV(+) and HPV(-) cohorts (p=0.27). However, the interval until
development of DM after RT was longer for HPV(+) DM than HPV(-) DM (1.6
year vs. 0.5 year, p=0.04). DM in multiple organ (>2) was evident in 11/24
HPV(+) compared to 0/12 for HPV(-) (p<0.01). The DM site in the HPV(-)
cohort was mainly lung followed by bone and liver: lung alone (9), lung &bone (2), liver & bone (1). Lung was also the most common DM site in the
HPV(+) cohort (15/24, 63%). However, in the HPV(+) group dissemination
to unusual sites was equally represented including skin (7), intra-abdominal(retroperitoneal, mesentery, and iliac) lymph nodes (5), brain (4), duodenum(1), paraspinal muscle (1), and axillary lymph nodes (1) (Table 1).

Bilateral RT in these patients, with its increased risk of xerostomia, can be
avoided. The risk for contralateral neck recurrence is low even in those patients with N2b disease.
853 poster
PEDIATRIC INTRACRANIAL EPENDYMOMA: OUTCOME AND
PATTERNS OF FAILURE FOLLOWING POST-OPERATIVE RADIOTHERAPY
D. Mansur1 , J. Leonard2 , M. Smyth2 , T. Park2 , D. Limbrick2 , A. King3 , J.
Michalski1 , A. Hollander3 , J. Rubin3
1
WASHINGTON U NIVERSITY M EDICAL C ENTER, Radiation Oncology, St.
Louis, USA
2
WASHINGTON U NIVERSITY M EDICAL C ENTER, Neurological Surgery, St.
Louis, USA
3
WASHINGTON U NIVERSITY M EDICAL C ENTER, Pediatrics, St. Louis, USA

Conclusions: While DM rate is unaffected by HPV status, dissemination of
HPV(+) OPC is more often observed at multiple organs and unusual sites,
and likely after longer intervals. The frequency of these events is low but may
have clinical implications in designing post-treatment surveillance protocols.
The routine assessment of HPV status for all OPC is warranted.
852 poster
PATTERNS OF FAILURE IN TONSILLAR CANCER PATIENTSTREATED RADICALLY WITH IPSILATERAL HYPOFRACTIONATED
RT
S. Loo1 , K. Geropantas1 , T. Bradnam2 , C. Martin1 , T. Roques1
1
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, Departmentof Oncology, Norwich, United Kingdom
2
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, Departmentof ENT, Norwich, United Kingdom
Purpose: To report the pattern of recurrence following radical hypofractionated three-dimensional conformal radiotherapy (3D CRT) to the ipsilateraloropharynx and neck in patients with T1-3 N0-2b squamous cell carcinomaof the tonsil with no tongue base or soft palate involvement.
Materials: We identified 725 patients with head and neck cancer treated withradiotherapy in our department between January 2004 and August 2009 fromour database. Of these, 41 had T1-3 N0-2b squamous cell carcinoma of thetonsil with no tongue base or soft palate involvement. They were all treatedwith hypofractionated 3D CRT to the ipsilateral oropharynx and neck, withor without chemotherapy. The high dose CTV included the primary site andinvolved nodal levels and received a dose of 55 Gy in 20 fractions over 4
weeks. The low dose CTV included the ipsilateral uninvolved nodal levels
at risk of microscopic disease, receiving a dose of 35.75 Gy in 13 fractions
over 2.5 weeks. Two or three unilateral beams were used matched to an
ipsilateral anterior low neck field. We analysed their pattern of recurrence
and loco-regional control rate.
Results: There were 36 male and 5 female patients. Median age was 57
years. 3 had stage I, 4 stage II, 9 stage III and 25 stage IVA disease. T
and N distribution were as follows: TX - 1, T1 - 22, T2 - 16, T3 - 2, N0 - 7,
N1 - 9, N2a 4 and N2b - 21. 11 patients received RT alone, 7 concomitant radiochemotherapy (CRT) and 23 induction chemotherapy followed by
CRT. Median follow-up was 23 months. Six patients had disease recurrence,
two within the oropharynx, two in the contralateral neck and two with distantmetastases. Median time to disease recurrence was 18 months. The twopatients with contralateral nodal relapse had N2b disease at presentation but
both had a negative PET-CT three months after treatment completion. Bothwere then treated with salvage surgery and postoperative CRT, but one developed a further recurrence in the contralateral neck and received palliative
chemotherapy. Contralateral nodal control was 95% for the entire cohort and
87.5% for patients with N2b disease.
Conclusions: Hypofractionated 3D CRT to the ipsilateral oropharynx andneck is a reasonable treatment option in patients with T1-3 N0-2b squamouscell carcinoma of the tonsil with no tongue base or soft palate involvement.

Purpose: A retrospective analysis of intracranial ependymoma was performed to determine the efficacy of surgery and post-operative radiation therapy and patterns of failure.
Materials: Fifty consecutive patients age less than 20 years with grade II or
III intracranial ependymoma and no evidence of disseminated disease havebeen treated between 1965 and 2008. The majority were male (52%) and
had infratentorial tumors (60%). Pathology slides were re-reviewed for the
20 patients for whom material was available. There were 25 World HealthOrganization (WHO) grade II tumors, and 25 grade III tumors. CSF cytology
was documented as negative in only 40% of patients, but no patient had
known disseminated disease. All patients received radiation therapy postoperatively to a median dose of 51.3 Gy (range 18-70). Eighteen patients inthe earlier era were treated with extended fields (11 craniospinal, and 7 wholebrain), while the majority (64%) received local field RT.
Results: The median age of patients was 7.2 years (range 1-19). With a
median follow up of 4.8 years, the 5 year progression-free survival (PFS) andoverall survival (OS) for all patients was 56% and 68%, respectively. Patientstreated in the modern imaging era had improved OS (81% vs 50%, p=0.05).
Patients with gross total resection had improved OS compared to those withbiopsy only or subtotal resection (82.4% vs 58.5%) but this difference did notreach statistical significance. Older children (> 7 years old) had improved
PFS (67% vs 44%, p=0.01) and OS (78% vs 58%, p=0.03). Higher radiationdose (>54Gy) was associated with improved PFS (78% vs 39%, p=0.02) andOS (88% vs 52%, p=0.03). Multivariate analysis revealed only younger age
to adversely affect PFS. No difference in outcome was seen based on WHO
grade, tumor location, gender, or radiation volume. Of the 24 patients whorecurred or progressed, 86% did so only within the irradiated volume. No
patient had an isolated failure outside the irradiated volume.
Conclusions: While the outcome of children with intracranial ependymoma
has improved in the modern era, disease progression is common, especiallyin younger children and after subtotal resection. The dose-response seen andthe lack of benefit to extended fields supports the modern radiotherapeutic
approach of high-dose RT to limited conformal volumes.
854 poster
PHANTOM-BASED VALIDATION OF AN ADAPTIVE RADIOTHERAPYSOFTWARE
E. Lennerts1 , J. F. Daisne1
1
C LINIQUE S T. E LISABETH, Radiotherapy Department, Namur, Belgium
Purpose: Fractionated stereotactic head and neck radiotherapy is often challenged by patients weight fluctuations, which may cause anatomical modifications with respect to the original planning CT. It may shift the isocenter andreduce plan conformity with PTV underdosage and radiation-induced toxicity as extreme potential consequences. Adaptive radiotherapy (ART) helps
to guide treatment plan adaptation in function of organ shape modifications.
This requires to re-scan the patient and re-contour both organs at risk (OAR)
and target volumes, which is time-consuming and practically impossible toperform online.Brainlab iPlan RT 4.5 ART software was designed to speed
up the adaptive workflow process by automatic deformation of delineated volumes from the original planning CT to follow-up CT or CBCT scans. This
allows fast and straightforward online evaluation of the validity of the original
treatment plan using CBCT data used for patient positioning. We aimed totest and validate the software on a basic phantom model, controlling isovolumetric and volumetric deformations.
Materials: A homemade, deformable low neck phantom was homemade withplaster, plasticine and plastic tubes, mimicking 6 vertebras, one mandible,
oral cavity and trachea. The plasticine was moulded on a neck support tomimick the neck and oral cavity soft tissues. The phantom was first CTscanned in a native position (CT4) with a native "soft tissue" volume. It was
subsequently mechanically deformed and rescanned (three scans: CT1 toCT3), and then shrunken by iteratively removing around 50 cc plasticine eachtime, followed by rescanning it every time (four scans: CT5 to CT8) The acquired CT-scans were transferred to the Brainlab workstation. "Bony" structures and body contours were manually segmented on every CT-scan. These

S 331

manually contoured gold standard (GS) volumes were compared to the contours resulting from the elastic fusion of the contours of CT4 to CT1 - CT3 andCT5 - CT8. Volume deformation relative accuracy was evaluated by comparing the absolute volume changes between the morphed ART volumes andthe GS ones. Dice similarity coefficient (DSC) index was used for objective
comparison purpose.
Results: All volumes taken together, individual DSC values ranged from 0.90
to 0.99. For the body, the mandible and the six vertebras, the mean DSC
indexes were 0.98, 0.94, 0.93, 0.96, 0.95, 0.95, 0.94 and 0.96 respectively.
Conclusions: In a simplified non rigid head and neck phantom model, theART software proved to be accurate. Validation should now be performed on
patients’ data sets.
855 poster
POSTOPERATIVE CONCURRENT CHEMORADIATION FOR HIGHRISK HEAD & NECK SQUAMOUS CELL CANCER
T. Antonadou1 , T. Paschalis2 , A. Silyvridou2 , D. Roumeliotis3 , M. Spyrakos2 ,V. Dimakopoulou4 , D. Pantazis3 , N. Throuvalas1 , I. Bankousli4
1
ATHENS M EDICAL C ENTRE, Radiation Oncology, Athens, Greece
2
ATHENS M EDICAL C ENTRE, Medical Physics, Athens, Greece
3
T HRIASION H OSPITAL, Head and Neck Surgery, Greece
4
ATHENS M EDICAL C ENTRE, Oncology, Athens, Greece
Purpose: Patients with locally advanced operable head & neck cancer are
at high risk for treatment failure. The integration of platinum based concurrent chemoradiotherapy (CRT) has improved loco - regional control leading
to improved disease free survival and overall survival. The aim of this study
was to evaluate the efficacy and toxicity of concurrent CRT administered after
transoral laser surgery.
Materials: Between October 2000 and February 2010 112 consecutive patients 105 men and 7 women, with a median age of 65 years (range 33-77)
with locally advanced resectable squamous cell head & neck cancer (SCCHN) were referred to our department after transoral laser surgery of the primary tumour and functional neck dissection. All patients underwent platinum
based concurrent CRT. Most common chemotherapy (CT) schedule was a
weekly 30mg/m2 cisplatinum. Primary sites included larynx (67 pts), oropharynx (40 pts) and hypopharynx (5 pts). AJCC stage was III in 65 pts and IVA
in 47 pts. All patients received radiotherapy with 6MV photon beam and 6-12
MeV electron beam combinations. Total dose ranged from 60Gy to 66Gy (2Gy /5 fractions per week) depending upon the extent of the disease, the surgical excision and the pathology report. 3D treatment planning was performed
for all patients and dose volume histograms for PTV, spinal cord and parotid
glands were calculated. After beam optimization was performed, PTVs received doses from 95% up to 107%, according to ICRU specifications. Doses
to the spinal cord ranged from 42Gy to 48Gy (in less than 2% of the cord) forall patients.
Results: All patients completed the treatment protocol and were monitored
weekly during CRT. Toxicities were graded following the RTOG scoring criteria. Parotid gland sparing was achieved depending on the tumour primarylocation, while in cases were the PTV extended superiorly, three quarters of
the parotid gland volumes received doses up to 50Gy. Median follow up of thepatients was 44 months (range 9-110months). Neither severe acute toxicity
nor grade IV haematological toxicity was observed. Acute grade III mucositis was recorded in 62pts (55%), dysphagia in 68pts (61%), xerostomia anddysgeusia in 24pts (21%) respectively. Late radiation side effects were evaluated at 2 years. Only 11pts (10%) presented xerostomia and 5 pts (4%)
dysphagia. 4 year disease free survival estimate was 55%. Functional larynx
preservation was possible in 57 pts (85%).
Conclusions: Concurrent CRT after transoral laser surgery for locally advanced SCCHN is an effective, well tolerated treatment. The loco regional
control and overall survival were significantly improved over those reported
for radiation treatment alone. It also offers functional organ preservation to
the vast majority of the patients with laryngeal carcinoma.
856 poster
PREDICTION OF DISPLACEMENT DURING RADIATION THERAPY(INTRAFRACTION MOTION) IN TREATMENT PLANNING FOR
PATIENTS WITH HEAD AND NECK NEOPLASM
M. Yamamoto1 , H. Hirakawa2 , K. Tanaka3
1
K URE N ATIONAL H OSPITAL , C HUGOKU D ISTRICT C ANCER C E, Radiation
Oncology, Kure, Hiroshima, Japan
2
K URE N ATIONAL H OSPITAL , C HUGOKU D ISTRICT C ANCER C E, Otolaryngology, Kure, Hiroshima, Japan
3
K URE N ATIONAL H OSPITAL , C HUGOKU D ISTRICT C ANCER C E, oral
surgery, Kure, Hiroshima, Japan
Purpose: The development of image guided radiation therapy (IGRT)
provides accurate daily patient set-up. However, there is no useful method
for prediction of displacement during radiation therapy (intrafraction motion).
We prospectively investigated and evaluated the displacement in treatment
planning for patients with head and neck neoplasm.

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H EAD N ECK CANCER

H EAD N ECK CANCER

Materials: Between February 2007 and February 2010, 33 patients withsquamous cell carcinoma of the head and neck were immobilized with anindividual thermoplastic mask and received both unenhanced and contrastenhanced computed tomography (CT) scans using a 64-multidetector
CT scanner. Following unenhanced scan, a contrast bolus (100ml) was
administered over 50 seconds and immediate imaging acquisition followed.
One hundred seconds after completion of the bolus, a delayed imaging
acquisition obtained. It was about 3 minutes from unenhanced scan todelayed imaging acquisition. Scan data were sent to planning system, on
which the displacement between unenhanced imaging and delayed imaging
were measured. For each patient, five points were defined to determine
the displacement: bilateral mastoid process, mandibular process, dens andspinous process of fourth cervical vertebrae.
Results: The average translocation difference was 1.07 +/- 0.38 mm inbilateral mastoid process, 1.65 +/- 0.64 mm in mandibular process and1.03+/- 0.24 mm in dens and spinous process of fourth cervical vertebrae.
We found large displacement beyond average translocation difference in 2
patients.
Conclusions: We could predict the displacement by compared unenhanced
imaging with delayed imaging. If we found large displacement in treatment
planning, we have to try to improve immobilization or add more margins inplanning target volume.
857 poster
RADIOTHERAPY FOR SCHN IN MULTI-MORBID PATIENTS OR IN
CASE OF CHEMOTHERAPY RESISTANT TUMOURS
J. Szabó1
1
A LBERT S ZENT-G YÖRGYI U NIV.M ED.S CH ., Department of Radiotherapy
Oncology, Szeged, Hungary
Purpose: From June 2007. cetuximab with concurrent radiotherapy (E-RT)
was introduced in our institute. This report summarizes the results of ourdata.
Materials: A prospective analysis of 26 pts (median age 56.7 years- range
38-77) with loco regionally advanced/ recurrent (3 cases) squamous cell headand neck cancer (stage III-IV, epi-, meso-, hypopharynx) was performed.
Chemotherapy was contraindicated in 10 cases because of co-morbidity andin 13 cases because of not responding tumour to neoadjuvant chemotherapy.
EGFR inhibitor cetuximab was received weekly with 400 mg/m2 initial dose,
followed by weekly doses at 250 mg/m2 (mean 4.3; 2-10 cycles). All patientswere treated with CT or PET/CT based 3D conformal RT and received mean
69.6 Gy (range 61.2-72) full dose. Adapted volume was defined for boost
after 50Gy based on repeated planning CT- CT fusion.
Results: In 3 cases of recurrent SCCHN the E-reRT were tolerated well resulting in tumour regression. 21/23 pts completed the E-RT. Grade III radiodermatitis/ radiomucositis (N=19). was managed with fraction dose reduction(3 pts) or with intermittent pause (16 pts). 1 progression, 4 stable disease
and 16 partial remission were detected after the 22. RT fractions (39-43 Gy)
made retopoCT-CT fusions. Complete remission was detected in 5 cases after full dose of E-RT. The 1-year loco regional relapse-free survival rate was
14. 3 %. The 2- year disease- free survival was 23. 8 %.
Conclusions: While E-RT is an effective combination in the local control andtreatment response of SCCHN, because of relative high toxicity it’s seems
that the adequate patients selections and the best supportive care are essential. The further benefit can be expected from addition of sequantionaland concomitant chemotherapy.
858 poster
RADIOTHERAPY IN T1 GLOTTIC CANCER: HAVE WE REACHED A
CEILING?
K. Geropantas1 , S. Loo1 , C. Martin1 , T. Roques1
1
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, Departmentof Oncology, Norwich, United Kingdom

Purpose: 1) To analyze the recurrence-free, laryngectomy-free and diseasespecific survival rates of patients with T1 glottic squamous cell carcinoma
treated with hypofractionated three-dimensional conformal radiotherapy (3D
CRT) at our institution 2) To compare our results with published data from theera of two-dimensional simulator-based radiotherapy (2D RT) planning andconventional fractionation
Materials: For the last 8 years, patients presenting to our institution with T1
glottic squamous cell carcinoma have been treated with 3D CRT according
to ICRU guidelines. The GTV consists of the primary tumour as identified
on CT and nasendoscopy. The CTV comprises the entire laryngeal aperture
with a margin of at least 10 mm superiorly and inferiorly from the GTV. A 3
mm margin is then added to the CTV to form the PTV. The superior treatment field border is usually at the level of the mid-body of the hyoid bone
and the inferior border at the inferior edge of the cricoid cartilage. Treatment

consists of two anterior oblique or parallel opposed lateral beams. An anterior beam is sometimes required to ensure at least 95% dose coverage of
95% of the PTV. Standard dose-fractionation is 55 Gy in 20 fractions over 4
weeks. A smaller number of patients received 50 Gy in 16 fractions over 3.5
weeks. We analysed the recurrence-free, laryngectomy-free and diseasespecific survival rates of 100 consecutive patients treated with this techniquebetween January 2003 and January 2010
Results: There were 89 male and 11 female patients. Median age was 71
years. Fifty-nine patients had T1a and 49 T1b tumours. Anterior commissure
involvement was noted in 43% of cases. Dose-fractionation was 55 Gy in 20
fractions over 4 weeks in 74 patients, 57.5 Gy in 20 fractions over 4 weeks in
2 patients and 50 Gy in 16 fractions in 24. Median follow-up was 28 months.
Eleven patients recurred, all within the treated volume. Of these, 6 had T1aand 5 T1b tumors with 6 having anterior commissure involvement. Mediantime to recurrence was 13 months. Seven had salvage total laryngectomy; ofwhom one recurred at the tracheostomy site and died from his disease. One
patient had a partial laryngectomy. Four patients had laser excision, of whom
1 had a further local recurrence and subsequent laryngectomy. There was adifference in recurrence rates between the two fractionation regimens (7% for
the 55 in 20 vs 21% for the 50 in 16). Overall recurrence free rate was 89%
and laryngectomy free rate 92%. Disease specific survival rate was 99%
Conclusions: Hypofractionated 3D CRT resulted in recurrence-free,laryngectomy-free and disease-specific survival rates that were comparablewith published data from the era of 2D RT and conventional fractionation inpatients with T1 glottic squamous cell carcinoma. This suggests that - as opposed to other body sites - improvement in RT techniques has not translated
into better outcomes in T1 glottic cancer
859 poster
RADIOTHERAPY INDUCED PAIN IN HEAD AND NECK CANCERPATIENTS TREATED WITH BUPRENORPHINE
J. Menten1 , K. Van Beek1 , H. De Schutter1 , I. Carpentier1
1
U NIVERSITY H OSPITAL G ASTHUISBERG, Radiotherapy-Oncology, Leuven,
Belgium
Purpose: Many head and neck cancer (HNC) patients have painful dermatitis
and mucositis due to radio(chemo)therapy. The intake of oral analgesics isdifficult and often postponed leading to under treatment of pain. This study
evaluated the need for transdermal buprenorphine in HNC patients treated to≥50Gy-72Gy ± chemotherapy.
Materials: This prospective non-interventional study started to include patients, after giving informed consent, during the second week of their radiotherapy or radiotherapy and chemotherapy/cetuximab (combined treatment)
for head and neck cancer. Demographic and treatment-related variables wererecorded: age, sex, medication use, and anticancer treatment (irradiation,
chemotherapy, target therapy). Radiotherapy induced dermatitis and mucositis were scored according to the Common Toxicity Criteria 3.0 and patients’
pain intensity was scored (VAS). Patients were asked to register their daily
analgesic consumption in a diary and were seen weekly for clinical examination, pain assessment and scoring of toxicity and adverse events. Pain
was first treated with either paracetamol to a maximal dose of 4000mg/day ortramadol to a maximum of 400mg/day. In case of insufficient pain relief, transdermal buprenorphine was started at 17,5 µg/h and was gradually increased
when pain scores were >30/100. Tramadol or buprenorphine sublingual wereavailable for breakthrough pain in doses equivalent to 1/6 (VAS >50) or 1/12
(VAS <50) of the daily equivalent buprenorphine dose. Weekly visits were
foreseen during and after the irradiation until the patient was back at the original pain medication level before radiotherapy.
Results: Forty-five patients were included in the study. Nineteen of them had
VAS pain scores below 30 and stayed on paracetamol or tramadol treatment.
Moderate to severe pain (VAS >30) was present in 26 patients 4 weeks after
the start of radiotherapy and persisted at least for 2 weeks after the end of
irradiation, these were treated with buprenorphine. Patients irradiated <70Gy
needed a mean dose of 20-30 µg/h buprenorphine, patients with ≥70Gy
needed 40-50 µg/h while the combined treated patients needed 50-60µg/h
to keep the VAS pain scores between 30 and 50. Even with buprenorphine up
to 70µg/h was the mean VAS-score for pain still ≥40/100 during 3 measure
points for RT ≥70Gy and the combined treatment patients. Laxatives wereused in about 50% of the patients receiving buprenorphine and 10% in thenon buprenorphine treated patients.
Conclusions: Twenty-six patients irradiated for head and neck cancer needbuprenorphine due to insufficient pain relief with paracetamol or tramadol.
Patients were treated with doses up to 70µg/h buprenorphine although themean pain VAS-scores were temporarily ≥40/100. Patients and caregivers
have to up titrate buprenorphine dose more assertively to better relief treatment induced pain.

860 poster
RADIOTHERAPY WITH FRACTION SIZE OF 2.25GY IN T1-2 LARYNGEAL AND HYPOPHARYNGEAL CANCER
K. Karasawa1 , H. Hirowatari1 , T. Furuya2 , S. Ozawa2 , S. Sugimoto2 , K.
Sasai1
1
J UNTENDO U NIV. FACULTY OF M EDICINE, Department of Radiation
Oncology, Tokyo, Japan
2
J UNTENDO U NIV. FACULTY OF M EDICINE, Department of Medical Physics,
Tokyo, Japan
Purpose: To evaluate the influence of fraction size of 2.25Gy on local controlof T1 and T2 laryngeal and hypopharyngeal cancers.
Materials: Between August 2002 and December 2010, 80 patients with T1
andT2 laryngeal or hypopharyngeal cancers were treated with definitive radiotherapy with a fraction size of 2.25Gy to a total dose of 63.0 Gy. Primarysites were larynx in 69 and hypopharynx in 11. Fifty-three patients were T1
and 27 were T2. All patients’ pathology was squamous cell carcinoma except
one carcinosarcoma. The radiotherapy was delivered 5 days per week with a
4-MV photon of Varian 21EX, opposite fields using electronic tissue compensation of Eclipse with a radiation dose homogeneity within ±7% in the central
axis plane. Acute toxicities were assessed weekly and graded according to
CTCAE v 4.0. Treatment response was assessed at 1 month after treatmentcompletion. The late adverse effects have been observed every 3 months after the treatment and scored by CTCAE v 4.0. Statistical analysis of survival
was calculated using the Kaplan-Meier method. The relapse-free survival
rates were compared with our historical control of fraction size of 2.0Gy.
Results: Overall treatment time ranged from 38 to 49 days (median: 41days). No grade 3 toxicities including mucositis or dermatitis was observed.
All patients obtained complete response. The median follow-up period was
25 months (ranging from 2 to 101 months). Eight patients developed a recurrence, 6 were in local and 2 were in neck lymph nodes. Three patientswere dead, 1 was of laryngeal cancer and 2 were of intercurrent diseases.
The two-year relapse-free survival rate was 87.3% and five-year rate was
68.9% in the entire group, respectively. Significant prognostic factors at twoyear relapse-free survival rates were primary site (100% in hypopharynx, and84.8% in larynx), and T stage (92.3% in T1, 78.2% in T2). Comparing the results with historical control, two-year relapse-free survival rates were(2.25Gy
vs 2.0Gy), 90.4% vs 88.5% for T1 larynx cases, and 85.7% vs 76.3% for T2
larynx cases.
Conclusions: Fraction size of 2.25Gy may increase relapse-free survival
rates from those of 2.0Gy in T1 and T2 lesions of larynx.
861 poster
RAPID SYMPTOMATIC HELICAL TOMOTHERAPY IRRADIATION:FEASIBILITY AND EVALUATION OF CONFORMITY INDEX ANDOARS DOSE
P. Antognoni1 , A. Bruni1 , E. Cenacchi2 , G. De Marco1 , G. Guidi2 , B.
Lanfranchi1 , E. Mazzeo1 , B. Meduri1 , M. Parmiggiani1 , G. Tolento1 , E.
Turco1 , C. Danielli2 , F. Bertoni1
1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Radiation Therapy,
Modena, Italy
2
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Physics, Modena, Italy
Purpose: To evaluate workflow and feasibility of rapid palliative irradiationby helical Tomotherapy (StatRTTM ), and potentials of better conformity index/OARs dose in a retrospective series of 14 symptomatic metastatic patients (pts).
Materials: Between March 2009 and October 2009 at the Radiotherapy Department of Modena 14 pts with symptomatic metastasis were prospectively
accrued to establish the workflow, to define the procedures, and evaluate
the clinical benefit of helical Tomotherapy for scanning, planning, and delivering treatment in a single radiotherapy (RT) date. Patient mean age was
67.7 years (range: 48-95). Twelve pts received RT for palliation of painfulbone metastasis, 1 pt for important rectal bleeding, and 1 for symptomaticlung lesion. Twelve patients were treated at 1 single site while in 2 pts RT
was delivered to 2 metastatic sites in a single session. 28.6 % of cases
were re-treatments to previously irradiated sites. After patient positioning on
the treatment couch, a Megavoltage CT (MVCT) with superior/inferior borders
encompassing the intended treatment volume was done to define on-line contouring of GTV, and GTV expansion of 1 cm to PTV. IMRT plans were created
and optimized to the PTVs. The necessary time for each treatment phase(set-up, MVCT, contouring, plan calculation and RT delivery) has been registered and each patient compliance evaluated by creating an arbitrary index
score (1=good, 2=fair, 3=poor). A dosimetry comparison between conventional 3D-CRT and Tomotherapy rival plans was also performed by evaluating
Conformity Index (C.I.) and OARs and PTV dose distribution
Results: Mean overall treatment time (pt IN-OUT) for the 14 treated pts was
106.3 min. (range: 48-180 min.), with longer time in pts with lower compliancescore (3 pts) and multiple lesions (2 pts). Median compliance score for thewhole group was 1.The comparison of rival plans (3D-CRT vs. Tomotherapy)
which was done in all pts showed an improvement of C.I. (0.034 +/- 0.021
vs. 0.026 +/- 0.014), a decrease of median dose to OARs (13.4 Gy +/- 9.08

S 333

Gy vs. 7.09 Gy +/- 5.14 Gy) and a better PTV coverage (V95Dp) in favour ofTomotherapy. During the analysis period a reduction in total treatment time
was observed which was directly proportional to the progressive improvementof technical skill of the RT staff and to satisfactory patient compliance, and thiscan probably lead to an average machine occupation time lower than 1 hour
per patient
Conclusions: Rapid palliation with helical tomotherapy may be considered
in compliant patients who need urgent treatment of symptomatic metastasis,and especially in those requiring re-treatments after previous RT, with CI and
OARs dose gain. Further prospective studies in larger patient series seemwarranted in order to more accurately define workflow procedures and thecosts/benefits ratio of this modality, particularly in poor compliant patients.
862 poster
RE-IRRADIATION OF RECURRENT AND/OR PERSISTENT SQUAMOUS CELL CARCINOMA OF HEAD AND NECK REGION
K. Singh1 , S. Shekhar1 , J. D. Baruah1 , A. K. Bahadur1 , A. Gulati1 , A. K.
Rathi1M AULANA A ZAD M EDICAL C OLLEGE, Radiotherapy, New Delhi, India

1

Purpose: The squamous cell carcinoma of head and neck region is among
most common types of cancer in India. Here the most common form of failure
after irradiation is local recurrence. Reported incidence of local recurrence
varies between 15-50%. The most important factors related with it are size ofprimary tumor and presence of nodal metastasis. The other factors contributing are extra capsular spread of lymph node metastasis, peri-neural involvement, positive surgical margins and tumour differentiation.The managementof recurrence and residual disease in head and neck region is challenging.
After failure of primary radiotherapy or combined modalities, surgery will be
helpful only in selected small T1, T2 disease or isolated neck node recurrence. But not at all useful in advance cases, even palliation is not possible
by surgery. The choice of palliative chemotherapy in recurrent or metastatic
head and neck cancer continues to be controversial as long term prognosis
is poor and quality of life with chemotherapy is not always improved. Reirradiation may occasionally be attempted in certain cases after failure of primary radiotherapy. Literature of re-irradiation of recurrent local head and neckcancer, reported long term survival in 13 to 20% of patients.Our aim of study
was to document "role of re-irradiation in patients with unresectable, recurrent
and/or persistent previously irradiated squamous cell carcinoma of the headand neck region in terms of palliation and tolerance to therapy".
Materials: Patients included in the study were histologically proven locoregional recurrence and/or persistent disease in an area that had previously
been irradiated to a standard dose of 60-65 Gy in 6-7 weeks, unresectabledisease and without distant metastases. There should be a minimum gapof 6months from primary radiotherapy. Patient excluded were non-squamouscell carcinoma and ECOG >2.After routine work up all patients were irradiated by teletherapy to a dose of 45 Gy by conventional fractionation after andassessed by WHO criteria and pain scoring.
Results:

Conclusions: Re-irradiation is a potential option for giving the symptomatic
relief in patients with inoperable recurrence. This results in a fairly good symptom free survival. But more data are needed to prove that it is a viable option
for treatment of recurrence by conventional or newer techniques of radiotherapy.
863 poster
REDUCTION OF SET-UP MARGINS WITH THE USE OF A CBCTIMAGE-GUIDED PROTOCOL IN THE TREATMENT OF HEAD AND
NECK CANCER PATIENTS
F. Dionisi1 , M. Palazzi1 , M. G. Brambilla2 , C. Carbonini2 , F. Bracco1 , A.
Torresin2
1
A ZIENDA O SPEDALIERA O SPEDALE N IGUARDA C A ’G RANDA, Radiotherapy
Unit, Milan, Italy
2
A ZIENDA O SPEDALIERA O SPEDALE N IGUARDA C A ’G RANDA, UNIT OF
MEDICAL PHYSICS, Milan, Italy
Purpose: 1) To evaluate set-up accuracy in head and neck (H&N) radiotherapy with the use of cone beam computed tomography (CBCT) and 2) todetermine the effectiveness of an internal online correction protocol in maximising the dose delivery precision and in reducing set-up margins from CTV
to PTV.

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H EAD N ECK CANCER

H EAD N ECK CANCER

Materials: Patients undergoing postoperative or definitive radiotherapy for a
H&N cancer were immobilised with a 4-point head and shoulder thermoplastic mask and treated with the use of an Elekta linear accelerator mounting a
CBCT scanner (Elekta Synergy, Elekta Oncology Systems Ltd, Crawley, UK).
Both conventional 3D and IMRT techniques were adopted. Image registration
was performed using soft-tissue algorithm applied to an extensive region ofinterest including the whole PTV. Image guided radiotherapy was performed
for the first 3 fractions of treatment, then weekly. An on-line correction protocol was adopted, with the first 3 scans used to correct systematic errors witha 3 mm Action level. Only translational (no rotational) errors were considered by the present analysis. The overall mean shift (M), the SD of the groupsystematic error (S), the root mean square of the SD of all patients (s) andthe 3D vector of displacement were calculated. The Van Herk recipe (2.5 S+
0.7 s) was used to determine CTV to PTV margins. Margins for geometric
uncertainties around the spinal cord were calculated according to the formulaby Mackenzie (1.3S + 0.5s). The impact of the correction protocol was determined quantifying the set-up accuracy without the application of systematic
adjustments.
Results: Forty-four patients treated at our Unit between June 2009 and July2010 were considered for this analysis. A total of 420 CBCT scans (average
9.5 scans per patient, range 6-14) were analysed. 1260 positional errors inmedio-lateral (ML), supero-inferior (SI) and antero-posterior (AP) directions
were recorded. A systematic correction according to the 3 mm Action levelprotocol was applied in 40% of patients. A set-up error > 3 mm occurredin 176/1260 (13.9%) measurements, mostly (79/176) in SI direction. Bothin case of application of the protocol and if no systematic corrections wereapplied, the value of overall mean displacement (M) was below 1 mm in
the 3 directions. Values of and in ML, SI and AP axes were 1 mm, 1.1
mm, 1.2 mm and 1.5 mm, 1,8 mm, 1,9 mm, respectively. Overall set-up
accuracy was described in table 1. The mean 3D vector of displacements
was 1.93 0,79 mm. Set-up margins from CTV to PTV were 3.48 mm, 4.08mm and 4.33 mm along the 3 axes. Margins to generate PRV for the spinal
cord were 2 mm, 2,38mm and 2,5mm in ML, SI, and AP directions. If
systematic corrections were not considered, the values of raised to 1.4mm, 1.7 mm and 1.8 mm in the 3 directions, while the mean 3D vector
length increased to 2.56 ± 1.44 mm. Set-up margins with no systematic
corrections raised to 4.48 mm, 5.58 mm and 5.83 mm in ML, SI and AP axes,
respectively. In absence of systematic corrections, a PRV margin for the
spinal cord of 2,52 mm, 3.16 mm and 3.29 mm along the 3 axes was required.

Conclusions: Kilovoltage CBCT image registration is an effective tool to determine set-up accuracy for head and neck cancer patients. The low valueof M detected confirmed the reliability of set-up procedures and of the equipments used at our Unit. The correction protocol allowed for a 30% reductionof the SD of the systematic errors (S) in all directions. The minimum estimated CTV-PTV margins, accounting only for set-up errors, were reduced
to < 5 mm along the 3 axes. Reduction of random set-up errors could beachieved by increasing the number of image-guided fractions.
864 poster
RESULTS FROM INDUCTION DOCETAXEL, CISPLATIN, AND FLUOROURACIL (TPF) FOLLOWED BY CONCOMITANT CISPLATIN PLUS
RADIOTHERAPY IN LOCALLY ADVANCED NASOPHARYNGEALCANCER (NPC)
E. Kerboua1 , K. Bouzid1
1
P IERRE AND M ARIE C URIE C ENTER, 1st Clinical Oncology Department,
Algiers, Algeria

Purpose: In squamous cell carcinoma of head and neck cancer, TPF induction chemotherapy (CT) improved survival over cisplatin plus fluorouracil(MR. POSNER:NEJM,vol357,oct 2007). The main objective of this study is toevaluate the activity and safety of TPF in patients (pts) with locally advanced
NPC followed by concomitant cisplatin plus radiotherapy (cCTRT).
Materials: Pts with undifferentiated NPC were enrolled from December
2006December 2009, and received 3 cycles of TPF (docetaxel 75 mg/m2 andcisplatin 75/m2 day 1, plus fluorouracil 750 mg/m2 days 15, every 4 wks) with
G-CSF days 15 post CT. Induction CT was followed by cCTRT with cisplatin
40 mg/m2 /wk and radiotherapy (6570 Gy) starting 4 6 wks after the third cycleof induction CT. The primary endpoint was overall response rate (ORR) after
induction CT and after cCTRT. Secondary end points were toxicity, disease
free survival (DFS), and overall survival (OS).
Results: Thirty-three (33) pts with locally advanced NPC have been enrolled(19 M/14 F). UICC 1997 classification: n=2 stage II, n=15 stage III, n=16
stage IV (n=6 IVA; n=10 IVB). Median age is 37 yrs (range 1854). Evocative
clinical signs are cervical nodes n=16, rhinologic n=8, otologic n=6, and neurologic n=3. All pts were evaluated for safety and 27 for response. TPF waswell tolerated with main toxicities grade 34 (WHO) consisting of neutropenia 33%, thrombocytopenia 30%, anemia 18%, diarrhea 6%, and mucositis
18%. One pt died from sepsis that was probably treatment-related. ORR was
90% with an 81.4% (n=22) complete response (CR) rate, 11.1% (n=3) partial response (PR), and 7.4% (n=2) stable disease. No pts progressed after
induction CT. Main toxicity during cCTRT was neutropenia grade 34 in 7%,
mucositis grade 3 in 44% and grade 4 in 3.7%. Late toxicities were xerostomia grade 3 in 50%. At treatment completion, CR and PR rates were 74%
and 18.5%; 2 pts had stable disease. At a median follow up of 20 months(range, 736), 3, 4% of pts have shown recurrence or progressive disease.
DFS and OS rates at 24 months were 75% and 80%, respectively.
Conclusions: TPF followed by cCTRT appears to be an active and feasible regimen with an acceptable tolerability profile and may be a promisingtherapeutic option for pts with high stage NPC.
865 poster
RETROSPECTIVE STUDY OF POSSIBLE REASONS FOR RECURRENCE AFTER RADIOTHERAPY OF HEAD AND NECK CANCER
E. Samsøe1 , J. Bentzen1
1
U NIVERSITY H OSPITAL H ERLEV, Department of Oncology, Herlev,
Denmark
Purpose: The purpose of this ongoing study is to detect possible reasons for
locoregional recurrences in patients who have previously received (chemo) radiotherapy (RT) for their head and neck cancer. The goal is improve
our procedures as we learn from any mistakes made or suboptimal procedures performed in the target definition, the planning process and/or during
the treatment course itself. Ultimately, the study is anticipated to minimize
the number of unintended events in connection to contouring, planning andtreatment of patients with head and neck cancers.
Materials: From October 2009 to November 2010, twenty-tree patients withrecurrent disease after (chemo-) RT of head and neck cancer were registered in our institution. The patients were originally treated for cancers in thelarynx (seven), the mouth (four), the oropharynx (seven), the hypopharynx(three) and the rhinopharynx (two). The originally contoured target volumes
were reviewed by experienced radiologists and oncologists and all originallyavailable scans, such as MRI and CT, were available during the evaluation.
All dose plans were reviewed by an experienced physicist and evaluated withrespect to the present guidelines for target coverage of head and neck cancers. The physicist evaluated the daily patient setup errors by considering
the daily kV images and their respective match to the corresponding digitallyreconstructed radiographs (DRRs) originating from the planning CT scan.
Results: In two patients (9%) the relapses may have derived from geographic
miss due to insufficient target delineation. Two of the treatment plans (9%)
used tangential fields in the treatment of the larynx, which is in contradiction
to our institutional guidelines. The online setup errors exceeded our local
tolerances during four treatment courses (17%). However, it was found thatthese setup errors did not result in any compromise of dose at the sites ofrecurrences. The total acceptable treatment time (42 days) was exceeded intwo (9%) treatment courses.
Conclusions: As a result of our findings, several initiatives have been established. A check-list will be introduced to ensure that the physicians areaware and in possession of all present diagnostic images (e.g. MRI, CT,
PET) when delineating the target. Systematic reviews of the contoured volumes have been introduced at daily PTV conferences and a local target delineation workshop is planned for January 2011. Furthermore, a local workshop
has been organized in order to re-educate dose planners regarding field techniques. Instructions have been revised and personnel have been re-informed
and re-educated in our tolerance policy regarding patient positioning during
treatment. A radiobiology group has been established in order to develop
guidelines for handling any unintended breaks and compensation for suchbreaks in the course of treatment.

866 poster
ROLE OF FDG PETCT IN DIAGNOSIS AND MANAGEMENT OF
OLFACTORY NEUROBLASTOMA.
P. McCloskey1 , M. Moran2 , S. Napier3 , D. Stewart4 , W. Primrose2 , S.
Hughes5
C LINICAL O NCOLOGY, N ORTHERN I RELAND C ANCER C ENTRE , B ELFAST
H EALTH AND S OCIAL C ARE T RUST,, Department of Radiation Oncology,
Belfast, United Kingdom
2
N ORTHERN I RELAND R EGIONAL H EAD & N ECK S URGERY U NIT, Head
Neck Surgery, Belfast, United Kingdom
3
R OYAL V ICTORIA H OSPITAL, Department of Pathology, Belfast, United
Kingdom
4
N ORTHERN I RELAND C ANCER C ENTRE, Clinical Oncology, Belfast, United
Kingdom
5
R OYAL V ICTORIA H OSPITAL, Department of Radiology and Nuclear
Medicine, Belfast, United Kingdom
1

S 335

mask yielded high positioning reproducibility for our patients. To spare theparotid gland in the proximity of the target, a fraction of the target volume may
not receive the prescribed dose. In the best-achievable plan of our studiedcohort, only 43% of parotid gland volumes were treated to more than 30 Gy,
while an average of 7,8% of the target volume received less than 95% of theprescribed dose. This is mainly related to the steep dose gradient in the region where the target abuts the parotid gland. The inverse planning systemallowed us the freedom of weighting normal tissue-sparing and target coverage to select the best-achievable plan. Local control was achieved in all, but
one patients, who showed a PD after six months.
Conclusions: A system for patient immobilization, setup verification, anddose optimization for head and neck cancer with parotid sparing without significantly compromising target coverage is being implemented for a
tomotherapy-based IMRT plan at the Radiotherapy Division of Lecce Hospital. The initial clinical experience in tumor control is promising, and no severe
adverse acute side effects have been observed.
868 poster

Purpose: Olfactory neuroblastoma (ONB) is a rare tumor of neuroectodermal
origin that arises from the olfactory epithelium in the roof of the nasal cavity.
The stage is highly predictive of survival and local disease has an excellent
prognosis. Surgical treatment for localized disease is successful, however
there is also a role for postoperative radiotherapy. Radical radiotherapy canbe used if surgery is not deemed to be appropriate and chemotherapy has
a role for tumor spread beyond the nasal cavity and paranasal sinuses. The
current imaging modality of choice for assessment of these tumors is contrast enhanced computed tomography (CT), although magnetic resonanceimaging (MRI) has a role also. This case series indicates a role for [F18]2’-fluoro-2’-deoxy-D-glucose (FDG) positron-emission tomography combinedwith CT (PETCT) for radiological evaluation of ONB.
Materials: A retrospective review of the medical records of all patients diagnosed with ONB in Northern Ireland between 1996 and 2009 was carried out.
FDG PETCT images were analyzed where available and correlation madewith clinical data. Eight patients (4 male, 4 female) were included, and threeof these individuals had FDG PETCT scanning.
Results: FDG PETCT is an effective imaging tool for assessment of newly
diagnosed ONB, recurrence of disease and distant metastases. Findings on
PETCT images correlated with the clinical picture in the three cases studied.
Increased FDG uptake was seen in all confirmed recurrent ONB. One case
had FDG positive directed surgical management of recurrent disease on two
occasions. The final FDG PETCT indicated no recurrence and the patient
remains alive and disease free. The second patient presented with Kadish
stage IV disease, which was positive on FDG PETCT. Response to therapy
assessment with FDG PETCT was negative and the patient died approximately 12 months after treatment. The third patient also had Kadish stage IV
disease which was also FDG positive, but the patient rapidly deteriorated anddied eight days following PETCT scan.
Conclusions: PETCT is an effective tool in the imaging of ONB. ONB tumors
appear to be FDG positive and this characteristic highlights the perceived
benefit of PET-CT over conventional CT imaging.
867 poster
SERIAL TOMOTHERAPY BASED IMRT IN HEAD AND NECKCANCER: OUR INITIAL EXPERIENCE.
D. Russo1 , A. Papaleo1 , E. Cavalera1 , A. Leone1 , M. G. Natali2 ,G. Ronzino3 , A. Palumbo4 , C. Nuzzo5 , G. Pastore2 , F. Fiorica6 , M.
Santantonio1
1
R ADIATION T HERAPY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
2
M EDICAL P HYSICS U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
3
O NCOLOGY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
4
OTORINILARYNGOIATRY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
5
R ADIOLOGY U NIT O SPEDALE V ITO FAZZI, Lecce, Italy
6
R ADIATION T HERAPY U NIT U NIVERSITY H OSPITAL F ERRARA, Ferrara, Italy
Purpose: To investigate the feasibility and the optimization of serial
tomotherapy-based IMRT in patients with head and neck cancer treated withsimultaneous integrated boost technique.
Materials: From November 2008 to May 2010, 13 patients with squamouscell locally advanced carcinoma of the head and neck were treated with IMRT.
Patients were immobilized with a noninvasive mask and treated using a serial tomotherapy device on a 6 MV linear accelerator (Siemens Primus MD.)
Treatment planning was performed on a Peacock inverse planning systemand prescription optimization was used to achieve the best plan for target
coverage and parotid sparing. The treatment planning system process has adosimetric characteristic of delivering different doses to different target structures simultaneously in each daily treatment. Therefore, three different doses
were delivered, 2.33 Gy , 2 Gy and 1.8 Gy daily to reach a total dose of 69.9,
60 and 53 Gy. All patients but two received concurrent chemotherapy.
Results: Median follow-up was 12 months (range 1-17). All patients completed the prescribed treatment without unexpected interruption. Acute side
effects were tolerable and comparable to those of patients treated with conventional beam arrangements. Only a patient required nasogastric feeding
tube. The preliminary experience showed that the noninvasive immobilization

SIMULTANEOUS INTEGRATED BOOST 18FDG-PET BASED HELICAL TOMOTHERAPY IN RADICAL LOCALLY ADVANCED HEAD AND
NECK CANCER.
I. Dell’Oca1 , C. Fiorino2 , A. Fodor1 , A. Chiara1 , E. Villa1 , W. Casagrande1 ,A. Rognone3 , M. Pasetti1 , S. Broggi2 , E. Busnardo4 , C. Landoni4 , L.
Gianolli4 , R. Calandrino2 , N. Di Muzio1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Radiation Oncology,
Milan, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
3
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Oncology, Milan, Italy
4
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Nuclear Medicine,
Milan, Italy
Purpose: To evaluate acute, late toxicity and early outcome of Helical Tomotherapy (HT) in radical locally advanced Head and Neck cancer patientstreated with the Simultaneous Integrated Boost (SIB) technique with dose
escalation to PET/CT positive tumor sub volumes .
Materials: Sixty two patients who underwent HT for locally advanced Headand Neck cancer (stage III IV B) were prospectively evaluated. Twenty six
patients were affected by Nasopharynx cancer, 27 Oropharynx, 5 Larynx, 2Hypopharynx and 2 Oral Cavity. HT was delivered with the SIB technique atdifferent dose levels: 69Gy (2.3 Gy/day) to the PET-positive volume, 66 Gy(2.2 Gy/day) to the clinical target volume and metastatic nodal station, 54 Gy(1.8 Gy/day) to the clinical negative neck region concomitantly. Concurrent
chemotherapy was given for 46 patients (cisplatin 75-100 mg/m every three
weeks, or 30 mg/m weekly for 42 patients and Cetuximab for 4 patients).
Care was taken to minimize as much as possible the dose to many structures(mucosae outside PTV1, larynx, oesophagus, inner ear, thyroid, brain, lungs,
sub-mandibular connective tissue, bones structures) without compromising
the respect of the constraints set for PTV coverage and the remaining OARs
like spinal cord, brain stem and parotids.
Results: All patients completed the treatment. Fifty-five patients had Radiation Therapy Oncology Group Grade (G) 0-1 acute salivary gland toxicity
while no G3 toxicity was seen. Twenty five and 21 patients had respectively
G 2 and 3 acute mucositis, while 35 and 12 acute G 2 and 3 skin reactions,no G4 toxicity was seen. Six patients were lost at follow-up while for theremaining 56, with a median follow-up of 18 months (3-64), 41 were locoregionally NED, 13 patients experienced locoregional relapse while for 9 pts
distant metastasis were seen. For patients with more than six months followup, no severe late toxicity was seen. Four patients experiencing taste suppression and 7 G2 salivary gland toxicity.
Conclusions: These preliminary findings show that SIB-HT with dose escalation to 18FDG-PET positive tumor sub volumes is a feasible technique also
when administered concurrently with chemotherapy and might also prove to
be biologically more effective. Taking care in sparing normal tissues, HT allows very acceptable rates of acute toxicity while shortens the overall treatment time in radical treatment of patients with advanced head and neck cancer. Although the results are promising, a larger population of patients anda longer follow-up period are needed to evaluate ultimate tumor control andtoxicity.
869 poster
SIMULTANEOUS INTEGRATED BOOST VOLUMETRIC MODULATEDARC THERAPY (SIB-VMAT) IN HEAD AND NECK TUMORS
F. Deodato1 , S. Cilla2 , G. Macchia1 , M. Massaccesi1 , E. Ippolito1 , C.
Digesù1 , P. Bonomo1 , V. Picardi1 , P. Viola3 , D. Sabatino2 , M. craus2 , V.
Valentini4 , N. Cellini4 , A. Piermattei2 , A. G. Morganti1
1
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Radiation Oncology, Campobasso,
Italy
2
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Physics Unit, Campobasso, Italy
3
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Physics Unit, Roma, Italy
4
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Radiation Oncology, Roma, Italy

S 336

H EAD N ECK CANCER

H EAD N ECK CANCER

Purpose: Volumetric modulated arc therapy (VMAT) holds the promise of improving both plan quality and delivery efficiency as compared with fixed field
IMRT. This study evaluate the performance of VMAT in the treatment of headand neck tumors in a simultaneous integrated boost approach, assuming SIBIMRT as a benchmark.
Materials: CT datasets of 6 patients, previously planned and treated with
fixed field step and shoot IMRT (SS-IMRT), were used for re-planning withdouble arc VMAT. All plans were generated with the treatment planning system (TPS) Masterplan Oncentra (Nucletron. The Netherlands) for an Elekta
Precise linac with 1 cm leaf MLC. Three PTVs were defined from the respective clinical target volumes adding 4 mm with 3D expansion. Dose prescription was 67.5 Gy at 2.25 Gy/fraction to primary tumour, 60.0 Gy at 2.00
Gy/fraction to intermediate risk nodal region and 55.5 Gy at 1.85 Gy/fraction
to low risk nodal region. All volumes were treated simultaneously according to SIB approach. Planning objectives for PTVs were V95%>95% and107%<1% of prescribed dose. Planning organ at risk volumes (PORV) wereobtained from respective OARs adding a 4 mm 3D expansion. Maximum
doses to spinal cord, brainstem and chiasma PORVs were limited to 45 Gy,
50 Gy and 50 Gy, respectively. For parotids, D50%<30 Gy and Dmean<26 Gy
were assumed as objectives. Plans for SS-IMRT and VMAT were comparedby means of Dose-Volume Histograms (DVH). Minimum doses (D99%), maximum doses (D1%), mean doses, homogeneity and conformality index wereused for plan comparisons.The delivered time and the monitor unit (MU) number were analyzed to score the treatment efficiency.
Results: Target coverage and homogeneity results improved with VMAT technique compared to IMRT. V95% increased from 98.2%, 98.4% and 98.2%(IMRT) to 98.4%, 98.5% and 99.1% (VMAT) for PTV1, PTV2 and PTV3, respectively. For PTV1, V107% decreased from 4.6% from 3.5% from IMRT to
VMAT. D99% increased from 63.0 Gy, 55.9 Gy and 51.7 Gy (IMRT) to 63.5
Gy, 56.6 Gy and 53.3 Gy (VMAT) for PTV1, PTV2 and PTV3, respectively.For
spinal cord PORV, average D1% decrease from 41.9 Gy and 40.0 Gy. On
brain stem, D1% was found 28.9 Gy and 31.5 Gy for IMRT and VMAT, respectively. The D50% to the contra-lateral parotid reduced from 24.9% (IMRT) to
24.5% (VMAT). The mean number of MUs per fraction resulted to be 563 for
IMRT and 496 for VMAT. Overall delivery time was found 21.2 minutes for
IMRT and 4.5 minutes for VMAT.
Conclusions: VMAT technique was able to deliver a simultaneous integrated
boost in head and neck tumours. Double arc VMAT showed improvements
in target dose homogeneity and conformality and similar OARs sparing as
respect to IMRT technique. Overall, the VMAT plans significantly reduced
MU and treatment time as compared to IMRT by 12% and 79%, respectively,
making possible the delivery of SIB treatments in less than 4.5 minutes on a
Elekta Precise linac. These results can lead to clinically significant advancesin the management of head and neck cancers, in addition to the positive impact on patient comfort and clinical workload. VMAT is currently our standard
intensity-modulated radiotherapy approach for head and neck tumors.
870 poster
SIMULTANEOUS INTEGRATED BOOST WITH VOLUMETRIC INTENSITY MODULATED RADIOTHERAPY(RAPID ARC) IN THE RADICALTREATMENT OF 51 ADVANCED HEAD AND NECK CANCERPATIENTS: A PRELIMINARY REPORT.
F. Alongi1 , S. Pentimalli1 , E. Clerici1 , P. Mancosu1 , L. Cozzi2 , R. Cavina3 ,A. Fogliata2 , S. Castiglioni1 , A. Tozzi1 , P. Navarria1 , A. Chiti4 , A. Santoro3 ,M. Scorsetti1
1
I STITUTO C LINICO H UMANITAS, Radiotherapy and radiosurgery department, Rozzano (Milan), Italy
2
IOSI, Bellinzona, Switzerland
3
I STITUTO C LINICO H UMANITAS, Medical Oncology, Rozzano (Milan), Italy
4
I STITUTO C LINICO H UMANITAS, Nuclear Medicine, Rozzano (Milan), Italy
Purpose: To report early toxicity results and preliminary clinical outcomesof radical radiation treatment of 51 advanced head and neck cancer patients(pts) using a moderately hypofractionated simultaneous integrated
boost(SIB) approach delivered with volumetric modulated arcs (Rapid Arc
technology).
Materials: Between February 2009 and September 2010, 51 head and necksquamous cell carcinoma(HNSCC) pts were treated at Humanitas ClinicalInstitute with Rapid Arc(RA) (35 males and 16 females; median age 67
years).Thirty-nine patients were classified as stage IV, 7 were stage III and3 stage II. Of these, 20 pts received concomitant chemotherapy with Cisplatin 100mg/mq (every 3 weeks), 3 pts other chemotherapy regimens, 21
pts Cetuximab, 7 pts were treated with RT exclusively. All pts were treated as
exclusive curative intent. Dose was prescribed at Planning Target Volumes(PTV) with simultaneous integrated boost: 54.45Gy (to elective lymph node
regions) and 69.96Gy (to T and N+) in 33 fractions. In the last 8/47 pts, FDG
PET images were utilized to define T and N+. From CTVs(clinical Target
Volumes) to PTVs, the margins applied were 4mm in all directions, considering that patients were repositioned every day by cone beam CT(CBCT)
that take set-up errors into account. Inverse planning optimisation was performed on the planning station; parotid glands, esophagus, chiasm, eyes, ocular nerves, spine, oral mucosa, were considered as OARs. For all patients,
set-up was assessed before each fraction through CBCT image guidance.

Clinical and treatment data, including dose-volume histogram (DVH) werereviewed. Acute toxicities were evaluated and scored in terms of mucositis, radiation dermitis and dysphagia, according to the Common Terminology
Criteria for Adverse Events (CTCAEv3.0) system developed by the National
Cancer Institute. Clinical Outcomes were assessed with RECIST Criteria system. The median follow up time was 8 months (range:3-18). All patients were
evaluated weekly during the RT course and after the completion of the treatment with a predefined follow-up schedule every three months.
Results: Concerning planning optimization strategies and constraints, as per
PTV coverage, for all groups, D98%>95% and V95%>99%. Conformity Index
CI ranged from 1.02±0.03 to 1.07±0.03. As regards organs at risk, all planning objectives were respected, and this was correlated with observed acutetoxicity rates. Of the 51 patients, 12 experienced G3 mucositis, 7 G3 dermitis
and 3 had G3 dysphagia. Nobody required feeding tubes to be placed during
treatment. Acute toxicity is also related to chemotherapy. Two patients interrupted the course of radiotherapy because of a quick worsening of generalclinical condition. At Follow-up evaluation, considering clinical outcomes, 19
showed complete response, 2 showed stable disease, 10 pts were in progression; forty-six were lost, 5 pts died, 4 caused by the HNSCC progression.
Conclusions: These preliminary results stated that SIB using volumetricmodulated arc therapy by means of RA in radical treatment of advanced headand neck cancer is feasible, with acceptable toxicities. Further follow up isneeded to assess late toxicity and definitive tumor control outcome.
871 poster
THE EFFECT OF ZILONGJIN® IN PATIENTS WITH HEAD AND
NECK CANCER NEEDING RADIOTHERAPY WITH AND WITHOUTCHEMOTHERAPY
J. R. Resubal1 , M. J. Calaguas1
1
S T L UKE ’ S M EDICAL C ENTER, Radiation Oncology, Quezon City,
Philippines
Purpose: To evaluate whether the addition of Zilongjin® in patients with headand neck cancer needing radiotherapy with and without chemotherapy can
impact: incidence and time to onset of mucositis, pain, xerostomia; weightchange; Complete Blood Count (CBC) and Immune Deficiency Profile (IDP)
values; quality of life; compliance to treatment schedule.
Materials: Thirty six patients with cancer of nasopharynx, tongue, palate,paranasal sinus, larynx were enrolled. Computer generated randomization
assigned patients into 1 of 4 groups: radiotherapy+Zilongjin® , radiotherapy+placebo, chemoradiotherapy+Zilongjin® , chemoradiotherapy+placebo.
Patients and physicians were blinded from randomization. Four tablets ofZilongjin® were taken 3x a day. Toxicities were assessed at baseline thenweekly using: Oral Mucositis Visual Assessment, Brief Pain Inventory, University of Michigan Xerostomia Questionnaire, MD Anderson Symptom Inventory Head and Neck Module. CBC was taken at baseline then weekly
while IDP was taken at baseline and 1 month after completion of treatment.
Intention to treat analysis was used to determine: mean incidence and meantime to onset of oral mucositis, pain, xerostomia; mean weight change; meanchange in CBC and IDP values; mean change in scores for quality of life;
mean compliance to treatment schedule.
Results: Zilongjin® is a traditional Chinese medicine composed of 4 herbs.
For chemoradiotherapy ± Zilongjin® : incidence of mucositis, pain,
xerostomia was the same; onset of mucositis was earlier forchemoradiotherapy+placebo with hazard ratio of less than 1 forchemoradiotherapy+Zilongjin® (0.744); the same onset for pain andxerostomia; weight change showed decreasing trend for both groups;
difference in CD4/CD8 counts pre and post treatment were greater forchemoradiotherapy+Zilongjin® (3.505 versus -4.533, ANOVA>1); increased
incidence and earlier mean time to onset of anemia, neutropenia, thrombocytopenia for chemoradiotherapy+placebo; improved score for generalactivity and relations with other people for chemoradiotherapy+Zilongjin® ;improved compliance for chemoradiotherapy+Zilongjin® .
For radiotherapy±Zilongjin® : weight change showed decreasing trend forboth groups; difference in CD4/CD8 counts pre and post treatment were thesame; no incidence of anemia, neutropenia, thrombocytopenia; decreased
score for fatigue and shortness of breath for radiotherapy+Zilongjin® ; thesame compliance for both groups.
Conclusions: Trends show that Zilongjin® does not prevent mucositis, pain,
xerostomia. Hematologic enhancing action of Zilongjin® may have caused
the decreased incidence and delayed onset of anemia, neutropenia, thrombocytopenia while its immune system enhancing function and mild analgesic
property may have stabilized the CD4/CD8 counts and improved the qualityof life in chemoradiotherapy+Zilongjin® group thus increasing compliance intreatment schedule.

872 poster
THE IMPACT OF CONCOMITANT BOOST RADIOTHERAPY IN
CARCINOMA BASE OF TONGUE
A. RISHI1 , S. GHOSHAL1
1
P OST G RADUATE I NSTITUTE OF M EDICAL E DUCATION AND R ESEARCH,
Radiation Oncology, Chandigarh, India
Purpose: To retrospectively analyze the outcome of radical radiation in patients in patients with squamous cell carcinoma of base of tongue, and evaluate the efficacy of accelerated fractionation radiotherapy with concomitantboost schedule outside a trial setting.
Materials: Case records of 250 patients with carcinoma base of tongue,
treated radically at PGIMER, Chandigarh, from 2004 - 2008 were analyzed.
Radical radiotherapy comprised of conventional fractionation radiotherapy
with or without concurrent chemotherapy and accelerated fractionation radiotherapy with concomitant boost schedule. In conventional fractionation
radiotherapy, a total of 66 Gy was delivered in 33 fractions at 2 Gy per fraction (BED Gy10 = 79.2). In chemoradiation patient also received concurrent
cisplatin (100mg/m2 ) 3 weekly for at least 2 cycles. In concomitant boost
schedule, the large field was irradiated with 1.8 Gy/# to 45 Gy over 5 weeks
and the boost was given concomitantly during the last 3 weeks of treatment
as second daily fraction (1.5 Gy/#), with an interfraction interval of 6 hours.
The dose to tumour was 67.5 Gy (BED Gy10 = 78.98). There were 92 patients who were treated with concomitant boost schedule, while 158 patientswere treated with conventional fractionation schedule. Disease free survival
was evaluated and compared among the different groups using Kaplan Meiermethod. Toxicity and prognostic factors were also studied among the different
groups.
Results: The median age of the study group was 55. Number of patientsin stage I, II, III & IV were 5, 14, 64 and 167 respectively. There were 7 patients who did not complete their treatment and were excluded from analysis.
The 2 year actuarial disease free survival for stage III/IV disease was 50%
and 38% for concomitant boost and conventional fractionation radiotherapy,
respectively (p = .03). Maximum survival difference was observed for stage
III in favour of concomitant boost schedule. Distant metastasis was observedin 3 patients of concomitant boost schedule and 7 with other modality. In
concomitant boost schedule grade 3 mucositis and dermatitis were observedin 67% and 11% respectively. In conventional fractionation schedule Grade
3 mucositis and dermatitis was observed in 57% and 16% respectively. Using univariate analysis, advanced stage of disease, unscheduled treatment
breaks and age of patients were found to be poor prognostic factors.
Conclusions: More than 90% of patients with carcinoma base of tongue
presents with locally advanced disease in our institute. Radical radiation inthese patients resulted in a 2 year disease free survival of 40%. The useof accelerated fractionation with concomitant boost schedule can significantly
improve the outcome of treatment, particularly in stage III disease.
873 poster
THE ROLE OF PET-CT IMAGING IN HEAD AND NECK CANCERPATIENTS AFTER RADICAL CHEMORADIOTHERAPY
J. Sherriff1 , C. McConkey2 , T. Ogunremi3 , S. Colley3 , P. Sanghera1 , A.
Hartley1
1
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Cancer Centre, Birmingham, United Kingdom
2
C LINICAL T RIAL U NIT, U NIVERSITY OF WARWICK, Coventry, United
Kingdom
3
Q UEEN E LIZABETH H OSPITAL B IRMINGHAM, Department of Radiology,
Birmingham, United Kingdom
Purpose: Positron emission tomography with computerised tomography(PET-CT) scanning is increasingly being utilised in head and neck cancer
to assess response after radical concomitant chemoradiotherapy. The UK
NCRN PET-NECK trial is currently evaluating this extensively in a prospective format. Whilst the results of this trial are awaited, uncertainty remains
regarding the appropriate use and timing of PET-CT scanning for this patientgroup. The purpose of this study was to assess the use of PET-CT following
chemoradiotherapy at our institution.
Materials: All patients receiving radical chemoradiotherapy for head and neckcancer over a 5 year period were identified. Outcome data including local
control and overall survival was collected for all patients. The positive andnegative predictive values (PPV and NPV) of PET-CT for local recurrence
were calculated.
Results: Sixty nine patients who had a post treatment PET-CT were identified
from a total of 251 patients receiving radical concomitant chemoradiotherapy.
Median time from completion of chemoradiotherapy to PET-CT scan was 3.4(Range: 2-8) months. Median follow-up in surviving patients was 19.5 and20.1 months in the PET-CT and non-PET-CT groups respectively. Two year
local control rates were 73.1 (95% CI: 60.6-85.8) % and 77.7 (95% CI: 70.484.9) % in the PET-CT and non-PET-CT groups respectively. Two year overall
survival in the PET-CT group was 66.2 (52.8-79.3) % compared to 81.8 (95%
CI: 74.9-88.7) %, in those not having a PET-CT scan.Of the 69 patients who
had a post treatment PET-CT, 24 had local uptake: 8 within the primary tu-

S 337

mour site alone; 6 within the neck alone; 7 within both the primary site andthe neck nodes and 3 locally but at a different site. Local recurrence subsequently occurred in 19 of all patients scanned. The NPV and PPV for local
recurrence were 88.9% and 58.3% respectively.
Conclusions: Post chemoradiation PET-CT may aid subsequent management decisions. Patients with a negative PET-CT scan post radical chemoradiotherapy have an 88.9% chance of remaining free of local recurrence 20months post treatment.
874 poster
THE ROLE OF SALVAGE SURGERY IN THE TREATMENT OF
LOCOREGIONAL FAILURE AFTER RADIOTHERAPY OF BASETONGUE TUMOR
Z. Takacsi-Nagy1 , J. Fodor1 , F. Oberna2 , T. Major1 , M. Kásler2 , C. Polgár1
1
N ATIONAL I NSTITUTE OF O NCOLOGY, Department of Radiotherapy,
Budapest, Hungary
2
N ATIONAL I NSTITUTE OF O NCOLOGY, Department of Radiotherapy andHead and Neck, Laser and Reconstructive Plastic Surgery , Budapest,
Hungary

Purpose: In this study, the results of definitive radiotherapy (RT) and salvage
surgery treatment of base of tongue cancer were evaluated.
Materials: A total of 94 consecutive patients (16 female and 78 male) with
T1-4, N0-3 and M0 disease underwent definitive RT between 1992 and 2005.
External beam RT alone (mean dose, 63 Gy) or external beam RT (meandose 61 Gy) with brachytherapy boost (mean dose, 17 Gy) was given for 50
and 44 patients, respectively. Eight patients were subjected to neck nodedissection generally at the time of brachytherapy.
Results: At a median follow-up time of 95 months, 37 (39 %) patients had
no residual disease or locoregional recurrence, 34 (36 %) patients had logoregional residual disease, and 23 (25 %) patients developed locoregional
recurrence. The 5-year cause-specific survival for all patients was 45 % (43of 94). In multivariate analysis, N2-3 stage and histological grade 3 proved
to be independent negative predictors of cause-specific survival (relative risk:
2.2 and 3.1, respectively). The overall number of patients with locoregional
failure was 57. Salvage surgery was possible in 18 (32 %) patients; morethan half of the patients (31of 57) with locoregional failure was not suitable
for salvage surgery due to unresectable disease, poor health status or distantmetastasis. Salvage surgery was successful in 10 (56 %) patients, while 8
patients developed a second locoregional recurrence.
Conclusions: For patients undergoing definitive RT more effective follow-up
and care is needed to increase the rate of salvage surgery.
875 poster
THREE DIMENSIONAL CONFORMAL RADIOTHERAPY (3DCRT) OFHEAD AND NECK TUMOURS WITH MULTIPLE FIELDS, AVOIDINGTHE USE OF ELEC-TRON BEAMS FOR SPINAL CHAIN IRRADIATION AND HALF-BEAM TECHNIQUE FOR SUPRACLAVICULARIRRADIATION.
G. Martin1 , G. Totaro2 , M. D. Falco32 , E. Verga2 , V. De Chiara2 , P.
Morrone24
1
C ENTRO M ORRONE, Radiotherapy, Caserta, Italy
2
C ENTRO M ORRONE, Caserta, Italy
3
D EPARTMENT OF D IAGNOSTIC I MAGING , M OLECULAR I MAGING , I NTER VENTIONAL R ADIOLOGY AND R ADIOTHERAPY , Radiotherapy, Rome, Italy
4
C ENTRO R ICERCHE M ORRONE, Caserta, Italy
Purpose: Purpose A technique to irradiate the entire neck at a dose of 5054 Gy by a 3DCRT using multiple wedged fields with a single isocenter was
evaluated . This technique avoid the use of electron beams for spinal chain
irradiation and half beam technique for supraclavicular irradiation.
Materials: From July 2008 to october 2010 twenty patients with head andneck tumour were selected. 14 were affected by Laryngeal Ca., 1 by lymph
node metastasis from sqamous cell ca., 3 by oropharynx ca., 1 rinopharinx and 1 of tongue ca. Aged from 31 to 78 years (average 62). Tree hadan exclusive treatment, 17 a post operative, twelve underwent concomitantchemotherapy and two concurrent Cetuximab . All were T3-T4 from N0 to
N2. TC scan was used to determine the CTV and the OAR. CTV included
all the levels of neck lymph nodes. PTV was determined adding 1 cm to
CTV. Isocentre was placed at the geometric centre of PTV. Eight wedged
beams [OAD=330◦ , LDX=270◦ , LDXC=270◦ , OPD=210◦ 230◦ , OAS=30◦ ,LSN=90◦ , LSNC=90◦ , OPS=140◦ 150◦ ] conformed on PTV with MLC wereused. In eight cases (big shoulders), a ninth wedged beam [AP=0◦ ] wasadded . In OPD and OPS beams the gantry,the collimator angles and the
MLC configuration was custom to shield at best the spinal cord. 6 MV energy
Photon beams were used for all fields, except for OPD, OPS and AP, where 15
MV energy was used. The dose 50 Gy (54 Gy to the patients with lymph nodemetastasis from sqamous cell carcinoma) was prescribed to CTV(2 Gy/Fx) 5
day per week, with a median dose of 98% (within a range from 96,5% to99%). The dose to PTV was not considered and estimated because part of
the PTV ROI lies "in air", and so it didn’t take part in the calculation of doseS 338H EAD N ECK CANCER

H EAD N ECK CANCER

distribution. Seventy patients continued to the most risk area up to a dose of
60 Gy and three (exclusive RT) reached 70 Gy .
Results: Homogenous dose to CTV ranging from 85 % to 109 % of prescribed dose, was achieved. The dose to spinal chord lay from 40 to 45
Gy.The treatment was always completed. Only one patient got a week ofsuspension after 4 fractions caused by an infection. Acute side effects of thetreatment were moderate. All patients had a grade 1- 2 dermatological toxicity and only 2 grade 3 (Cetuximab patient). Dysphagia was mainly grade 2 in"only RT" and more severe (grade 3) in "concomitant therapy". Four patientswith concomitant chemotherapy got mucositis of grade 3 and the other got
mucositis of grade 2. Salivary change of grade 2 was reported in all patients.
At the moment only two patien with bilateral neck dissection devolope a necklinphedema. Among all patients, ,only tree suffered from a local recurrence(two laryngeal ca. N2 no chemotherapy and a tongue N2).

878 poster
VALIDATION OF ELASTIC REGISTRATION TO STUDY PAROTID
DEFORMATION IN HEAD AND NECK TOMOTHERAPY
E. Scalco12 , E. Faggiano13 , S. Liberini1 , C. Fiorino4 , E. Maggiulli4 , S.
Broggi4 , G. M. Cattaneo4 , R. Calandrino4 , G. Rizzo15
1
I STITUTO DI B IOIMMAGINI E F ISIOLOGIA M OLECOLARE , CNR, Segrate(Milano), Italy
2
U NIVERSITY OF M ILANO -B ICOCCA, Fondazione TECNOMED, Milano, Italy
3
P OLITECNICO DI M ILANO U NIVERSITY, Department of Bioengineering,
Milano, Italy
4
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
5
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Department of Nuclear Medicine,
Milan, Italy

Conclusions: Subclinical hypothyroidism is important sequelae seen in thetreated patients of head and neck when thyroid is in the radiation field. The
patients with age less than 41 years are more prone to develop hypothyroidism. Chemotherapy has not affected the incidence of hypothyroidism significantly. Also, the dose of radiation has not shown any statistically significant
difference.
877 poster
TOLERABILITY OF SEQUENTIAL CHEMORADIATION FOR HEAD
AND NECK CANCER PATIENTS OUTSIDE A CLINICAL TRIAL
T. Roques1 , K. Geropantas2 , Z. Tasigiannopoulos2 , S. Loo2 , C. Martin2

Conclusions: This technique for 3DCRT seemes routinely feasible and associated with moderate acute toxicity and thanks to the isocentric set up requires an easy and unique initial positioning to perform the entire treatment.Moreover it gives the possibility to raise the dose to the neck up to 54 Gy.
876 poster
THYROID DISEASES AS A SEQUELAE FOLLOWING TREATMENT
OF HEAD AND NECK CANCER
R. P. S. Banipal1 , M. K. Mahajan1 , B. Uppal2 , M. John3
1

C HRISTIAN M EDICAL C OLLEGE AND H OSPITAL, Department of Radiotherapy, Ludhiana, India
2
C HRISTIAN M EDICAL C OLLEGE AND H OSPITAL, Department of Biochemistry, Ludhiana, India
3
C HRISTIAN M EDICAL C OLLEGE AND H OSPITAL, Department of Medicine,
Ludhiana, India
Purpose: To evaluate the radiation induced sequelae on thyroid gland andinfluence of concomitant chemotherapy.
Materials: This prospective study was carried out on 53 patients of headand neck carcinoma in the age group of 30 75 years (55.9 years). Patientswere treated with external beam radiotherapy (52.8%) or concurrent chemoradiotherapy with 5-flourouracil and cisplatinum (47.1%). The target volume
included the thyroid gland, which received an average dose of 60 Gy in 30
fractions. Thyroid function tests were done at the start of radiotherapy. Follow
up thyroid function tests were done on completion of radiotherapy treatment,
at 3 months, at 6 months after treatment, and then every 6 months. Follow up
ranges from 3 - 51 months (median - 27 months).
Results: Subclinical hypothyroidism was seen in 4 (7.5%) of the 53 patients.
In three patients the incidence was seen after a gap of 12 months and in
one patient after a gap of 35 months. Of the four patients, three were ofage ≤ 41 years and 1 was of age 66 years. In younger age group (3039 years) patients, TSH shows statistically significant (P<0.05) increase in
TSH values(Image). No significant difference was observed in radiation andchemo-radiation treatment groups. (P>0.10)

1
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, ClinicalOncology, Norwich, United Kingdom
2
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, Norwich,
United Kingdom

Purpose: We routinely use sequential cisplatin/5-fluorouracil (PF) induction chemotherapy and radical radiotherapy with concomitant weekly carboplatin (SCRT) in the management of patients with locoregionally advanced
HNSCC. The aim of this study is to assess the tolerability of PF induction
chemotherapy and whether it may compromise delivery of the subsequent
radiochemotherapy.
Materials: The SCRT protocol in our department comprises up to 3 cycles
of PF induction chemotherapy with cisplatin 100mg/m2 on day 1 combinedwith continuous infusion 5-fluorouracil 1000mg/m2 /day days 1-5 administered
every 21 days. This is followed by curative RT with or without concomitantweekly carboplatin 100mg/m2 . We analyzed 190 consecutive patients treatedwith SCRT between March 2003 and May 2010.
Results: There were 144 males and 46 females. Median age was 60 years.
42 patients (22%) were older than 70 years. Primary tumour sites were as
follows: oropharynx - 123, larynx - 17, hypopharynx - 15, nasopharynx - 8,oral cavity - 7, nasal cavity - 2 and unknown upper aerodigestive tract primary - 18. 78% completed all planned cycles of PF. 15% and 7% of patients
had one and two cycles of PF omitted respectively. 28% required PF dose
reduction and 19% a change of chemotherapy from cisplatin to carboplatin.
Two patients (1%) died after the first cycle of PF as a result of neutropenic
sepsis. 7.4% required hospitalization for PF-related toxicities. Median timefrom the first cycle of induction chemotherapy until start of radiotherapy was
72 days. Serum haemoglobin was compared before first cycle of induction
chemotherapy and before start of radiotherapy and a reduction was seen in
87% of patients (mean fall of 2.5g/dl). 25% required a blood transfusion during either induction or concomitant chemotherapy. 95% of patients completed
radiotherapy as prescribed. 2.5% did not complete RT whilst RT treatment
duration was prolonged by more than two days in another 2.5%. In 63% of
patients no more than one cycle of concomitant chemotherapy was missed,
but 18% did not receive any concomitant chemotherapy with their RT.
Conclusions: PF induction chemotherapy in HNSCC can be delivered without compromising subsequent RT in almost all patients. A significant numberof patients do not complete all planned cycles of concomitant chemotherapy
but it is unclear whether this is due to the induction chemotherapy alone. Concerns remain over the significant number of patients who experience a dropin their serum haemoglobin levels from PF. The impact of this on hypoxia andtherefore on tumour control remains unknown.

Purpose: In Head and Neck Cancer (HNC), patients undergo significant
anatomical changes during a treatment course. In this context an important
issue is the analysis of parotid anatomical modifications in order to identify
potential predictors of toxicity and design optimized adaptive treatment plans.
To study these anatomical changes rigid registration is not sufficient and theintroduction of accurate deformable registration is needed.
In this work we propose and validate an elastic registration method toevaluate parotid deformation in HNC Tomotherapy
Materials: The original data set consisted of MVCT images of 11 patientstreated for HNC with Helical Tomotherapy. Image registration between MVCTat the beginning of treatment (MVCT1) and MVCT at the end (MVCT2)
was performed using a non-rigid approach based on Mutual information,
free-form deformation (FFD) and B-splines. The method consisted in apreliminary stage of rigid motion recovery and in a second step of local
deformable transformation.
In order to quantitatively evaluate the registration accuracy in the parotid
region, manual contours referred to parotids were drawn by 3 observers
on MVCT2. Automatic contours were generated on MVCT2 by a contour
propagation algorithm based on the deformation field obtained from theelastic registration: for each parotid, from contours manually drawn on
MVCT1 the algorithm generated a corresponding surface triangular mesh;
the mesh is deformed by displacing its vertices according to the displacement
map obtained from the deformable registration; finally, the deformed contours
were obtained by cutting the deformed mesh through planes corresponding
to the MVCT2 slices. The correspondence between automatic and manualcontours was analyzed using metrics based on contour distance (Average
Symmetric Distance (ASD), Maximum Symmetric Distance (MSD)) andarea overlapping (Dice). For each patient and each parotid gland, average
ASD, MSD and Dice were calculated between each manual contour and theautomatic contour. Statistical comparison was performed using the Wilcoxon
test.
Results: In the validation analysis, very similar values were found (average
ASD, MSD and Dice equal to 1.598, 9.738, 0.806 and 1.721, 10.073, 0.796
for manual and automatic contour, respectively). No significant differences(p-values>0.05) were present between manual and automatic metrics. This
result confirms that, in general, the deformable registration was successful inregistering MVCT studies.
Conclusions: The elastic registration method is effective in assessing deformation field in the region of parotids, as it can be observed from the validation results. Therefore this deformation field can be used to evaluate parotid
glands shrinkage during Tomotherapy.
879 poster
VARIATION IN CONTOURING BETWEEN HEAD AND NECK ONCOLOGISTS TREATING OROPHARYNGEAL CARCINOMA
L. Pettit1 , A. Hartley2 , S. Bowden3 , J. Cashmore4 , P. Sanghera2
1
Q UEEN E LIZABETH H OSPITAL , U NIVERSITY H OSPITAL B IRMINGHAM NHSF OUNDATION T RUST, Clinical Oncology, Birmingham B15 2TH, United
Kingdom2
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Clinical Oncology, Birmingham, United Kingdom
3
Q UEEN E LIZABETH H OSPITAL , U NIVERSITY H OSPITAL B IRMINGHAM NHSF OUNDATION T RUST, Clinical Trials Unit, Birmingham B15 2TH, United
Kingdom
4
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Department of Medical Physics and Radiation Safety, Birmingham, United Kingdom
Purpose: Consensus guidelines on elective nodal contouring exist when using intensity modulated radiotherapy (IMRT) to treat oropharyngeal carcinomas; however there are no agreed guidelines for defining the high dose clinical target volume (CTV). This study aims to establish current practice within
the UK.
Materials: Questionnaires were sent to UK Head and Neck Oncologists.
Data collected included access to IMRT, induction chemotherapy use, dose

S 339

/ fractionation and definition of CTV from gross tumour volume (GTV) defined as follows: Anatomical alone (An), Geometric alone (Gm) and Combined Anatomical and Geometric (cAG).
Results: Forty Oncologists replied from 33 centers. IMRT was used by 22
centers. Whilst all Oncologists used induction chemotherapy, frequencies
varied as follows: occasionally 15, frequently 22, always 3. TPF (Docetaxel,
Cisplatin, 5-FU) was used by 27; PF by 7 and 6 used both. In centers using
IMRT, 16 used 3 dose levels and 6 used 2 (see table 1). High dose CTV
growth from GTV was as follows: An: 1 centre, Gm: 6 centers, cAG: 15
centers. Intermediate CTV growth was as follows: An, 6 centers, Gm: 2centers, cAG: 7 centers (1 centre: information not available).
Conclusions: There is variation in the use of dose levels CTV formation
when using IMRT to treat oropharyngeal carcinomas. Furthermore, use of
induction chemotherapy is common practice and can influence final CTV(s).
Intermediate dose levels surrounding the GTV are used by a majority of UK
centers and allow reduction in normal tissues receiving the highest dose;
however research is required to evaluate the clinical benefits of this approach.

S 340

L UNG CANCER

L UNG CANCER

880 poster
WAITING TIME FOR RADIOTHERAPY IN MALIGNANT GLIOMAPATIENTS
M. Hetnal1 , J. Urbanski2 , B. Glinski3 , K. Malecki3 , A. Mucha-Malecka3 , P.
Dymek3
1
C ENTRE OF O NCOLOGY - I NSTITUTE MSC K RAKÓW, Radiation Oncology,
Krakow, Poland
2
S T L UKE ’ S H OSPITAL, Radiation Oncology, Tarnów, Poland
3
C ENTRE OF O NCOLOGY - I NSTITUTE MSC K RAKÓW, Head and Neck
Tumor Department, Krakow, Poland
Purpose: The aim of this paper is an assessment of influence of waiting time
for radiotherapy (WTR) on overall survival in patients with malignant gliomas
after resection.
Materials: 308 pts with malignant gliomas (glioblastoma - 198 cases,
anaplastic astrocytomas - 110 cases) were irradiated postoperatively (60 Gy;
2 Gy/fraction) between 1975 and 2005. WTR was defined as a period between the time of operation until the start of radiotherapy. Two thresholdvalues of WTR were assumed for the calculations: WTRI - 37 days and WTR
II - 46 days. Main endpoint of the analysis was 2-year overall survival (OS).
Univariate, multivariate and survival analyses of prognostic factors were performed using log rank, Cox’s proportional hazard method and Kaplan-Meiermethod respectively.
Results: The 2-year OS was 17% for all patients (glioblastoma 10%; anaplastic astrocytoma 30%). For all patients 2-year OS was significantly better in thegroup treated earlier than 37 days from the surgery rather than later (24% vs14%). The univariate analysis showed that age (favoured younger than 40
years old), tumor location (favoured frontal), tumor type (favoured anaplastic
astrocytoma) and waiting time for radiotherapy (treated earlier than 37 days
from the surgery) had a significant impact on OS. For the 2-year OS, theindependent prognostic factors were age and WTRI. Patients older than 40
years and those that started irradiation after 37 days from the surgery had respectively three times and one and half time more risk of death compared toyounger patients and those that started radiotherapy earlier.WTR II (46 days),extend of surgery and performance status appeared not to be of prognostic
significance in this group of patients.
Conclusions: In patients with malignant glioma irradiation should be started
within 37 days after the operation, especially in the group older than 40 years
and with the tumor location other than frontal.
881 posterWEEKLY POSITION, VOLUME AND DOSIMETRIC CHANGESDURING IGRT WITH KILOVOLTAGE CT-ON-RAIL FOR HEAD AND
NECK CANCER
Y. S. Kim1 , H. S. Jang1 , B. O. Choi1 , S. C. Yoon2
1
T HE C ATHOLIC U NIVERSITY OF KOREA, Department of Radiation
Oncology, Seoul, Korea Republic of2
T HE UNIVERSITY OF KOREA , C OLLEGE OF MEDICINE, Department ofRadiation Oncology, Seoul, Korea Republic ofPurpose: To investigate the setup error, weekly volume changes of target volumes and organ-at-risk and the resulting dosimetric changes during imageguided radiation therapy (IGRT) for head and neck cancer patients.
Materials: Twenty-eight patients of head and neck patients had treated withvolumetric IGRT. KVCT (kilovoltage CT) scans had repeat weekly for 3D conventional radiotherapy, and daily for IMRT using CT-on-rail. The set up error,
volume changes and resulting dosimetric changes of the gross target volume(GTV) and organ at risk (spinal cord) were measured.
Results: Mean set up error of all three axis was 1.67mm (95% CI, 1.60-1.74).
Each value of medial-lateral, anterior-posterior and superior-inferior is 1.91
mm (95% CI, 1.77-2.05), 1.64 mm (95% CI, 1.51-1.76) and 1.45 mm (95%CI, 1.34-1.55), respectively. Mean set up error of all three axis for each weekly
IGRT and daily IGRT was 1.72 mm(95% CI, 1.58-1.85) and 1.65 mm (95%CI, 1.56-1.73). Each value of 3 axis was 1.81 mm(95% CI, 1.55-2.08), 1.72
mm(95% CI, 1.51-1.92), 1.62 mm(95% CI, 1.39-1.85) for weekly IGRT and1.95 mm mm(95% CI, 1.79-2.11), 1.61 mm mm(95% CI, 1.46-1.76) and 1.38mm mm(95% CI, 1.27-1.5) for daily IGRT, respectively. Significant volume
difference of GTV was seen after 2 weeks (15.1%, p=0.001) and 3 weeks(7.1%, p=0.002) compared to previous week. There was significant volume
reduction for ipsilateral parotid gland at week 2 and week 4 (18.5%, p=0.001
and 4.4%, p=0.037 respectively) and contralateral parotid gland at 2 weeks
and 3 weeks (15.5%. p=0.002 and 5.0%, 0.024) No dosimetric change formean, minimal dose to GTV, mean dose to parotid gland and maximal doseto spinal code were noted.
Conclusions: Significant volume change was occurred after 2 weeks and3 weeks in GTV, and 2 weeks and 3 weeks in ipsilateral parotid gland andcontralateral parotid gland. These finding could be used the guidline of thetiming of a further adaptive planning for head and neck cancer. Although
there was a limitation of small number of cases, weekly volumetric IGRT can
improve patient set up and accuracy in radiation delivery.

Lung cancer
882 poster
3-YEAR OVERALL SURVIVAL FOR INOPERABLE NON-SMALL
CELL LUNG CARCINOMA PATIENTS TREATED WITH RADIOCHEMOTHERAPY - SINGLE-INSTITUTION RETROSPECTIVEANALYSIS.
J. Topczewska-Bruns1 , D. Hempel1 2 , B. Pancewicz-Janczuk3 , E. Sierko12 ,T. Filipowski1 , M. Wojtukiewicz2
C OMPREHENSIVE C ANCER C ENTER, Department of Radiotherapy,
Bialystok, Poland
2
M EDICAL U NIVERSITY, Department of Oncology, Białystok, Poland
3
C OMPREHENSIVE C ANCER C ENTER, Department of Physics, Bialystok,
Poland

1

Purpose: Radical surgery is treatment of choice in non-small cell lung cancer(NSCLC) patients (pts). However, approximately 30% of them are diagnosed
at an advanced stage of the disease or are inoperable due to comorbidities.
The aim of the study was to analyze efficacy and predictive prognostic factors
for OS in pts treated with 3-D conformal radiotherapy (CRT) in combination
with chemotherapy (CT) for inoperable NSCLC pts.
Materials: 43 NSCLS pts were treated with 3D-CRT and platinum-based
sequential (89%) or concurrent (11%) CT. In both cases conventional fraction
dose of RT was delivered using megavoltage X-ray energy (6, 9 and 15 MV).
Median age of the pts was 66 yrs (range, 41-81 yrs). The group consisted of
32 males and 11 females. Six pts were diagnosed at II B, 17 at III A and 20
at III B stage of the disease. In 16 pts tumor was situated in left lung, in 27 inright lung. Prior to the treatment, the median FEV1 was 1,93 l (72,3%). The
mean hemoglobin level prior to CT was 12,5 g/dl, prior the RT or RT-CT 11,6
g/dl and after completed treatment 10,6 g/dl.
Results: The mean radiation dose was 64.6 Gy (range, 54-68 Gy) with themean treatment delivering time of 50 days. The mean dose in ipsilateral lungwas 39,03 and 35,9 Gy while V20 69 and 63 Gy, for left and right lung,respectively. Contralateral lung (both left and right) received mean dose of
19,9 Gy, while V20 = 36 and 37 %, respectively. 3-year OS was 23% with a
median OS 19,5 months for all pts. However, patients with negative lymph
nodes N(-) had higher 3-year OS than lymph node positive NSCLC pts (33%vs 17,4% with a median OS 23 vs 19, respectively). Among patients withN positive disease median OS was 19 months and 17,3 months for N2 andN3 group, respectively. Hb level after RT correlated with OS (p<0.05), as
well there was tendency to correlation between pretreatment FEV 1 and OS
in negative lymph nodes pts. For pts with N+ a weak correlation between
duration of RT and OS was observed. In IIIA pts correlation between age ofpts and OS was observed (p<0.05).
Conclusions: The results of radiochemotherapy for inoperable NSCLC pts
are not satisfactory in aspect of overall survival. Patients with negative lymph
nodes had better overall survival than those with lymph nodes metastasis.
Better outcome is also associated with Hb level, spirometry parameters, duration of RT as well as age at the time of diagnosis.
883 poster
3–D NON-COPLANAR CONFORMAL RADIOTHERAPY FOR THE
TREATMENT OF STAGE I NSCLC – ITS USEFULNESS FOR CENTRAL TUMORS
K. Karasawa1 , N. Okano1 , Y. Machitori1 , T. C. Chang1 , G. Kuga1 , N.
Mitsui1 , N. Hanyu1 , N. Kunishima1
1
TOKYO M ETROPOLITAN KOMAGOME H OSP., Department of Radiation
Oncology, Tokyo, Japan

tumors. Median follow-up period was 39 months.
Results: Three-year local control rate, overall survival rate, cause-specificsurvival rate, and relapse-free survival rate for overall cases were, 86%, 67%,79%, and 56%, respectively. For central tumors, they were, 86%, 72%, 82%,
and 51%, respectively, and for peripheral tumors, they were, 86%, 63%, 75%,
and 59%, respectively. There were no differences between the two groups.
There were 7 Grade 3 pulmonary toxicities (9%), but there were no severe
adverse effects concerning serial organs.
Conclusions: 3-DNCCRT for stage I non-small cell lung cancer has beensafe and effective both for central and peripheral tumors, and might become
an alternative treatment for central tumors, which SBRT might cause serious
toxicities. Further follow-up with a larger number of cases were necessary.
884 poster
CHEMO-RADIATION ALONE, WITHOUT RESECTION, MAY OFFER
EXCELLENT LOCAL CONTROL AND SURVIVAL FOR INVASIVE
THYMOMA
R. Allison1 , S. Salenius2 , D. Dosoretz3
1
21 ST C ENTURY O NCOLOGY, Greenville, USA
2
21 ST C ENTURY O NCOLOGY, I NC., Research, Fort Myers, USA
3
21 ST C ENTURY O NCOLOGY, I NC., Fort Myers, USA
Purpose: Invasive thymoma is a rare diagnosis and larger published series
include patients treated decades ago often including diagnostic and therapeutic techniques that may now be considered antiquated. We examined thecurrent management of patients with this diagnosis using modern interventions.
Materials: An IRB-approved search of our database identified 45 patientswith the diagnosis of invasive thymoma (male-27, female-18, mean age 63
years). All patients underwent CT guided biopsy for diagnosis and CT scansfor extent of disease workup. PET/CT was undertaken in 17. No patient was
found to have metastases on imaging. All but 3 patients were taken to surgery
for definitive resection. A total of 12 patients were deemed unresectable due
to invasion of critical organs, 15 were debulked and 18 were rendered free ofgross disease. Consolidative radiation therapy was employed in all patients
via IMRT or 3-D technique achieving a median dose of 54 Gy (range 30-70.2
Gy) in once daily fractions of 1.8 or 2 Gy. Chemotherapy was delivered to 15
patients: preoperative cisplatin-based regimen for debulking in 6 patients andpostoperative carboplatin-taxol in 9.
Results: Follow up extends to 37 months. No statistical difference was foundfor survival or local control based on disease stage, surgical extent, radiation dose, chemotherapy, age, gender or performance status. Disease extent
based on CT and PET/CT was frequently able to predict resectability andimaging studies were integral to defining radiation treatment fields. Patients
who underwent gross resection did not appear to have improved local control
compared to those found unresectable and treated by combined chemoradiation. Preoperative chemotherapy, employed to debulk disease in 6 patients,
was found to offer tumor shrinkage of 50% based on serial imaging, andsurgical confirmation in 4 patients. Radiation and chemotherapy were welltolerated with no grade 3 toxicity.
Conclusions: The role of surgery for Invasive thymoma may be reconsideredas all 12 unresectable patients achieved excellent local control and survivalwith the use of chemoradiation. Eliminating resection could reduce a sourceof significant morbidity. Overall, a 95% local control rate post radiation was
found and this outcome appears improved over historical controls in which 2D treatment planning was often employed. Preoperative chemotherapy may
debulk lesions but the role of chemoradiation without resection should befurther explored in larger series.

S 341

total dose of 50-60 Gy given in 2 Gy/5 fractions weekly to a volume including
the primary tumor and the mediastinum. Biological and clinical parameters
were analyzed in regard to the overall survival (OS) using Kaplan-Meier.
Results: Complete or partial response was achieved at the end of therapy inall patients. The median follow up was 16 months (ranging 1,5 to 60 months)
after RT. The analysis showed a mean OS of 24,6 months, as the 3-years
cumulative survival was 19% regardless of the RT regimen. No statistically
relevant significance for the OS was found in regard to gender, age, histological subtype, tumour differentiation, haemoglobin levels and lung function
testing results before treatment. Irrespective of the applied RT regimen, statistically shorter OS was observed in patients in clinical stage III (mean OS 10 months) compared to patients in stage II (mean OS - 19 months) (=0.03),
irradiated volume more than 100 cm3 (=0.02), 1 and 2 ECOG (=0.014), lowvalues of FEV-1 in lung function testing at the end of RT (mean OS - 7,5months) compared to values close to 100% (=0.003).
Conclusions: Our data showed that the restriction of the PTV up to the volume of the primary tumor and the involved lymph nodes, as well as the different fractionating of RT dose did not result in poorer outcome. Only younger
patients below 50 yrs could benefit the irradiation of the mediastinum without
evidence for tumor involvement with longer OS. The prognostic significanceof clinical stage, ECOG, tumor volume and the respective treatment volume
was confirmed. Functional lung testing before therapy has not prognostic relevance; however, at the end of RT it might contribute to additional prognostic
evaluation.
886 posterCYCLIN D1 (A870G) GENE POLYMORPHISM IN LUNG CANCER
S. Cakina1 , T. Gulyasar1 , T. Sipahi1 , A. Özen2 , Z. Koçak2
1
T RAKYA U NIVERSITY M EDICAL FACULTY, Biophysics, Edirne, Turkey
2
T RAKYA U NIVERSITY M EDICAL FACULTY, Radiation Oncology, Edirne,
TurkeyPurpose: This study aims to identify the susceptibility of Cyclin D1 (CCND1)
A870G gene polymorphism for causing lung cancer.
Materials: CCND1 genotypes were determined in 75 patients of lung cancer
and in 65 control subjects. DNA was isolated from blood samples. A870G
polymorphism of the CCND1 gene was identified by using PCR and RFLP
assay.
Results: Median age was 62, 72 (96%) patients were male and 61 (71.3%)
patients were non-small cell lung cancer. The distribution of CCND1 A870G
polymorphism did not show significant difference among overall lung cancer
cases and controls (Table 1). However, the AA+AG genotype associated withan increased risk of metastases lung cancer cases (p = 0.048) has sown an
increased difference compared to the GG genotype (Table2). Genotype frequencies of patients and controls were both confirmed to the Hardy Weinberg
equilibrium.

885 poster
Purpose: Threedimensional non-coplanar conformal radiotherapy (3DNCCRT) has recently been considered promising for the treatment of stage
I non-small cell lung cancer (NSCLC). Usually, it is performed in the form of
SBRT using 10 20Gy fraction dose. However, this method is considered tobe contraindicated for so-called central tumors because of the toxicity of serialorgans, such as bronchus, great vessels, etc. We have been treating thesetumors with relatively small fraction dose (usually 3Gy) keeping BED10 at thesimilar level to that of SBRT. In this study, we compared the results of central
tumors and peripheral tumors.
Materials: Eligibility criteria were as follows: maximum tumor diameter not
greater than 5cm, PS between 0 and 2, and no limitation regarding age andpulmonary function. Radiotherapy was given with 6MV photon beam by fixed
10 non-coplanar conformal beams to a total dose of 75Gy in 25 fractions in
5 weeks. Irradiation was aiming at the ITV with proper margins. No ENI was
given. Between Jan. 2002 and Nov. 2008, 80 eligible cases were treated.
Age ranged from 53 to 91 (median 77). The male/female ratio was 59/21.
There were 48 T1 tumors and 32 T2. Fifteen tumors were sqcca, 56 adenoca, and 9 others. There were 66 inoperable cases (83%), among thempoor pulmonary function was in 48 (60%), and 14 operable cases, who refused operation. The average tumor size was 3.0cm (range; 1.0 to 5.0 cm).
There were 75 PS 1 and 5 PS 2 cases. Among the entire cases, 37 cases
were central tumors and the other 43 were peripheral tumors. There were
no differences in the patient characteristics between central and peripheral

COMPARATIVE ANALYSIS OF TWO RADIOTHERAPY REGIMENSFOR THE TREATMENT OF PATIENTS WITH NON-SMALL CELLLUNG CANCER
R. Lazarov1 , I. Mihaylova2 , N. Gesheva-Atanasova2 , S. Bakardjiev2
1
TOKUDA H OSPITAL S OFIA, Department of Radiotherapy, Sofia, Bulgaria
2
N ATIONAL O NCOLOGICAL C ENTER H OSPITAL, Department of Radiotherapy,
Sofia, Bulgaria
Purpose: The aim of the study was to compare the therapeutic results of two
radiotherapy (RT) regimens with different Planning Target Volume (PTV) andfractionation for the treatment of non-small cell lung carcinoma and to evaluate the prognostic significance of essential clinical and functional parameters
for the overall survival (OS).
Materials: In total, 76 patients with non-small cell lung carcinoma were recruited at the Department of Radiotherapy, Tokuda Hospital Sofia, and theClinic of Radiotherapy Department, National Oncological Hospital Sofia during 2005-2010. The patients were stage II-III, at a median age of 59,6 years(33-83 years). Definitive 3D conformal radiotherapy was performed in all patients using linear accelerators. In 46 patients RT was performed up to a total
dose of 51 Gy given in 3 Gy/4 fractions weekly to a treatment volume including
the primary tumor and the positive lymph nodes, while in 30 patients up to aConclusions: Our findings suggest that the CCND1 A870G polymorphism
might be a marker for genetic susceptibility to the clinical behavior of thetumors, such as cancer progression and treatment response.
887 poster
FIRST RESULTS OF CBCT ACQUISITION CONCURRENT WITH
VMAT DELIVERY FOR SBRT IN LUNG CANCER PATIENTS
M. Rossi1 , J. Knegjens1 , J. Belderbos1 , P. Remeijer1 , M. van Herk1 , J. J.
Sonke1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
Purpose: Volumetric modulated arc therapy (VMAT) recently replaced IMRTin stereotactic body radiotherapy (SBRT) for pulmonary lesions in our clinic,
considerably reducing treatment delivery times. Previous to VMAT treatment,S 342

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L UNG CANCER

patients received two preRT CBCT scans for tumour alignment and verification and a post treatment CBCT to evaluate intrafraction motion. With both
CBCT and VMAT being rotational modalities, concurrent image acquisitionand dose delivery became feasible and allows verification of the tumour position during treatment without an increase in treatment time. The purpose ofthis study is to evaluate the first clinical results of this new verification strategy.
Materials: VMAT plans using two coplanar arcs were optimized using the
SmartArc module in Pinnacle3 (Philips, Best, The Netherlands). 15 patients
receiving SBRT for NSCLC were setup according to departmental guidelines.
Cone beam CT scans (Elekta Synergy, Crawley, UK) were performed following our SBRT protocol which included both bony anatomy as well as tumour
registration. After setup correction had been performed and verified 4DCBCT
acquisition was started simultaneous with VMAT. This scan was checked oncompletion of the 1st arc before continuing with the second arc. If the visualcheck of this demonstrated a displacement in tumour position then registration and possible corrections were performed. Only when tumour position
was deemed correct was the second arc delivered with 4DCBCT simultaneous acquisition. Differences in setup correction between the preRT verification scan and each VMAT arc scan were evaluated. Group mean (M), systematic (Σ) and random (σ ) intrafraction position variability were calculated.
Results: In total 71 concurrent CBCT scans in 15 patients were analysed. In
some cases, the scan quality was less optimal than expected due to incorrect
automatic dark field calibration (which initially did not take MV delivery into
account). The imaging dose per scan was ~1-1.5cGy. (standard 4DCBCT
2cGy). In 4 patients a correction was performed in one fraction as a resultof the 1st VMAT arc scan. These discrepancies were >2mm but did not exceed 5mm (range -0.47 to 0.26cm). In general over the whole patient groupintrafraction motion between the preRT CBCT and the arc scans was small~1mm, for group mean(M), systematic(Σ) and random(σ ) errors indicating
negligible intrafraction motion. (Table 1) Larger differences were observed inpatients with setup corrections between arcs predominantly in cranial/caudal(CC) and anterior/posterior (AP) directions. Differences were negligible in thisgroup between the 2nd arc scan and the mid-fraction scan. (Table 1)

33% (2p=.002), 26% vs 7% (2p=.003), 17% vs 3% (2p=.007), 9% vs 1%(2p=.043) in HD AHF and CF groups respectively. Kaplan-Meier estimation
also favored HD AHF, log-rank chi-square 11.8, p=0.001 (pict.).

P. Leogrande1 , P. Salustri1 , S. Saccia1 , C. Aristei1
R ADIATION O NCOLOGY P ERUGIA, Perugia, Italy

1

HIGH DOSE ACCELERATED HYPERFRACTIONATED RADIOTHERAPY IN THE TREATMENT OF LIMITED STAGE SMALL CELL LUNGCANCER
Y. Skripchak1 , M. Valkov2 , S. Asakhin3 , G. Kononova2
1
M URMANSK R EGIONAL O NCOLOGICAL H OSPITAL, Medical Oncology,
Murmansk, Russian Federation
2
N ORTHERN S TATE M EDICAL U NIVERSITY, Department of Radiology andRadiation Oncology, Arkhangelsk, Russian Federation
3
R EGIONAL O NCOLOGY H OSPITAL, Radiation Oncology, Nizhny Novgorod,
Russian Federation
Purpose: To assess retrospectively survival of limited stage small cell lungcancer (LS-SSLC) patients received high-dose accelerated hyperfractionatedradiotherapy (HD AHF).
Materials: One hundred forty patients with LS-SSLC received sequential chemoradiation between December 1993 and December 2006 at the
Arkhangelsk Regional Oncology hospital were selected. All patients received no more than 2 induction and not less than 2 cycles of consolidation
chemotherapy by schemes EP, CAV or VEC in therapeutic doses. Radiotherapy was delivered using either conventional fractionation (54-64 Gy/27-32 fr.,
CF group) or accelerated hyperfractionation (1.3 Gy b.i.d. to 39 Gy, than 1.6
Gy b.i.d. to total 64.6 Gy, HD AHF group). Two-dimensional technique withelective lymph node irradiation to BED 40 Gy was used.
Results: Forty seven patients received HD AHF radiotherapy, 93 were assigned to CF group. Groups were well balanced according to the age (both56 yr, SD 9), proportion of women (8% vs 3%, Fisher’s exact test 2p=.224),
centrally located tumors (92% vs 85%, 2p=.232), and stage 3 (72% vs 65%,
2p=.092). The rates of grade 3+ pneumonitis and esophagitis were 4% vs
3%, 10% vs 7% in HD AHF and CF groups respectively, 2p<0.05. With median follow-up period of 13 years 1-, 3-, 5-and 7-year survival were 62% vs

INTEGRATION OF PET/CT BASED DCECT BLOOD FLOW ANDPERMEABILITY MEASUREMENTS IN THE PLANNING OF RADIOCHEMOTHERAPY OF LUNG CANCER
K. Szluha Lazanyi1 , A. Abramyuk2 , Pintye1

MOTION VERIFICATION WITH 3-D CBCT IMAGING AND ‘BACKUPGATING’ IN PATIENTS WITH MOBILE LUNG TUMOURS
P. Jain1 , A. Baker2 , J. Littler1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Department of Radiation
Oncology, Bebington, Merseyside, United Kingdom
2
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Departments of Radiation
Oncology and Cell Biology, Bebington, Merseyside, United Kingdom

U NIVERSITY OF D EBRECEN M ED. AND H EALTH S CIENCE C EN, Departmentof Radiation Oncology, Debrecen, Hungary
TU D RESDEN , M ED. FACULTY C ARL G USTAV C ARUS, Department ofRadiation Oncology, Dresden, Germany

HIGH DOSE-RATE (HDR) BRACHITHERAPY IN NON-SMALL CELLLUNG CANCER: A MONOISTITUTIONAL EXPERIENCE.
M. Lupattelli1 , M. Massetti1 , R. Bellavita1 , L. Falcinelli1 , G. Capezzali1 , M.

888 poster

892 poster

2889 poster

Conclusions: The introduction of simultaneous 4DCBCT acquisition during
SBRT VMAT treatment in lung cancer allows tumour position verification during treatment. Results indicate that for a subset of patients intra-treatment
monitor of tumour position is beneficial.

890 poster

1

Conclusions: The scheme HD AHF is non-toxic and probably accompaniedwith improved survival comparatively to conventionally fractionated radiotherapy to standard total dose in sequential chemoradiation for LS-SSLC.

Purpose: This is a retrospective analysis of our experience in order to evaluate the feasibility, toxicity and effectiveness of HDR endobronchial brachitherapy in non-small cell lung cancer patients, both as palliative or definitive
treatment.
Materials: We reviewed our database involving patients with histologicallyconfirmed non-small cell lung cancer undergoing palliative or definitive brachitherapy. A remote after-loading high-dose rate unit was used (Microselectron HDR Nucletron) with 10 Ci Ir-192 source. Brachitherapy consisted of
15-20 Gy in 3-4 fraction/1 week as palliative option and 30-35 Gy/6-7 fraction/1 week as radical treatment; after external beam radiotherapy a doseof 10 Gy in 2 fraction/1 week as a boost was used. Dose fraction of 5Gy
was prescribed at 1cm from the source. Clinical target volume was definedby broncoscopy as the tumor site (or surgical bed after surgery) plus a 2cm
of cranio-caudal margin. Response to treatment was evaluated by clinicaland/or radiological tools (broncoscopy, CT scan). Toxicity was evaluated according to RTOG-EORTC score systems. Survival analysis was calculated
from the date of brachitherapy with Kaplan-Meier method.
Results: From April 2004 to August 2010, 34 patients were treated at our Istitution. Four patients were not evaluable due to early death not related to thetreatment. Characteristics of patients were as it follows. Gender M/F: 27/3;
median age 70 years (range 41-84); median KPS 90% (range 70-100%); histology: epidermoid 23, adenocarcinoma 3, carcinoid 2, others 2 patients; siteof disease: main and lobular left bronchus 14, main and lobular right bronchus
13, trachea 2, carina 1; stage: 0/I 10 patients, II 3, III 4, IV 4, pathological R1
7 and recurrent disease 7. On admission symptoms referred were: dyspnoea
in 11, cough 7, hemoptysis 5, pneumonitis in 2 cases. Eighteen patients werepretreated with surgery and chemotherapy. Brachitherapy was administeredas adjuvant, radical and palliative treatment in 8 , 14 and 8 cases, respectively. The median total dose of brachitherapy was 20 Gy in 4 fractions (range
10-35Gy) and the median length of clinical target volume was 6 cm (range
3-8 cm). A total of 140 treatments were administered. No acute or late toxicity related to the treatment was registered. Overall clinical response rate was100%. 1-year and 2-year overall survival was 65.2% ± 9.9% and 35.6% ±10.5%, respectively. 1-year and 2-year disease-free survival was 47.8% ±10.4% and 37.2% ± 10.5%, respectively.
Conclusions: According our experience, HDR brachitherapy was feasible,
easy to administer in outpatient setting, well tolerated, providing good symptomatic relief and was effective both as adjuvant and radical option.

S 343

Purpose: The aim of this study was to investigate the local tumor blood supply parameters relative tumor blood volume (rTBV) and transfer coefficient(Ktrans) measurable with dynamic contrast enhanced computed tomography(DCE-CT) in patients with nonsmall-cell lung cancer (NSCLC) scheduled forradiation therapy (RT).
Materials: rTBV and Ktrans were assessed in 31 patients with inoperable
NSCLC (stage IIV), which received or did not receive induction chemotherapy (IChT) and were assigned to RT. To evaluate DCE-CT in the management of NSCLC patients, possible links between rTBV and Ktrans and timeto-progression (TTP), overall survival (OS) and maximal standardized uptake value (SUVmax) from fluorodeoxyglucose positron emission tomography(FDG-PET) as well as histological findings were analyzed.
Results: NSCLC showed a wide range of rTBV and Ktrans values depending on stage and IChT. A significant difference in rTBV values wasfound in patients with and without IChT. A negative correlation between rTBV
and TTP was revealed only in RT patients with curative therapeutic intent
who manifested progression in developing distant metastases (n=7, r=-0.96,
p=0.0006). An inverse correlation was shown between Ktrans and TTP(n=24, r=-0.53, p=0.008) in all RT patients. In patients with curative therapeutic intention, an inverse correlation between Ktrans and TTP was found(n=20, r=-0.53,2 p=0.016). No relevant correlation was found between rTBV,
Ktrans and SUVmax or histological subtypes and grading.
Conclusions: Tumor blood supply parameters derived from DCE-CT may be
useful to characterize tumor vascularity before radiotherapy in patients with
NSCLC and outcome prediction may be supplemented.
891 poster
LOCAL RELAPSE OF MALIGNANT PLEURAL MESOTHELIOMA: A
MONOISTITUTIONAL STUDY OF SALVAGE HYPOFRACTIONATED
RADIOTHERAPY WITH TOMOTHERAPY.
N. D Abbiero1 , P. Ciammella1 , M. Galeandro1 , E. Donini1 , R. Micera1 , E.
Cagni2 , A. Botti2 , C. Iotti1
1
A RCISPEDALE S. M ARIA N UOVA, Radiation Oncology, Reggio Emilia, Italy
2
A RCISPEDALE S. M ARIA N UOVA, Medical Physics, Reggio Emilia, Italy
Purpose: Malignant pleural mesothelioma (MPM) is a rare malignancy andits incidence is expected to continue in the near future and still there is neither
any cure nor any evidence of the optimal treatment. The prognosis for malignant mesothelioma remains disappointing, although there have been somemodest improvements in prognosis from newer chemotherapies and multimodality treatments. Radiotherapy has a role in both palliative and after extrapleural pneumonectomy (EPP). Recently, radiotherapy has also been used asa treatment on the pleural frame pleurectomy/decortication as radical treatment. But the lung and cardiac related toxicity, also using techniques suchas IMRT, reduce the likely benefit of this aggressive approach. In such scenario is more reasonable to use a less aggressive approach that preserves
the quality of life of patients. Treat only the sites of recurrence rather than thewhole pleural cavity with hypofractionated radiotherapy is a new approachthat is feasible and safe with modern radiation techniques.
Materials: From June to November 2010 eight patients with local relapse of MPM, primary treated with pleurectomy/decortication and adjuvant
chemotherapy cisplatin based, were analyzed. In all patients gross tumor
volume (GTV) was defined using (18) F-fluoro-2-deoxyglucose ((18)F-FDG)
positron emission tomography (PET) and thorax CT scan with specific contrast infusion protocol. Tumour motion is evaluated with the four dimensional(4D)-CT-PET scan. A 5 mm margin was added to the CTV to create the planning target volume (PTV).All patients underwent to hypofractionated radiation
treatment with IMRT technique using Helical Tomotherapy unit, delivering a
total dose of 48 Gy in 12 daily fractions.Plans were optimized for conformity
and target coverage with maximum OAR sparing. A Tomotherapy megavoltage computed tomography (MVCT) was performed every day to verify andcorrect the patient set-up.Patients were seen 6 weeks after RT completionand the local tumour response was evaluate with CT scan. Any toxicity wasrecorded according to the National Cancer Institute Common Terminology
Criteria for Adverse Events (CTCAE vs 3.0).
Results: All patients have completed treatment without acute toxicities. Today all patients are alive. At first radiological examination, 3 patients demonstrated thorax progression of disease, 2 stable disease and 3 partial response.
Conclusions: Hypofractionated IMRT on site of relapse of MPM is safe, but
the short follow-up does not allow us to draw conclusions and evaluation of
the quality of life is still in progress.

Purpose: Tumour motion is the largest intrafraction variation during radiotherapy in lung cancer. 4-D CT scanning is considered gold standard forincorporating tumour motion in radiotherapy planning. Tumour motion may
be affected during radiotherapy by changes in breathing pattern, chest infection, and side effects. Hence tumour motion verification is important during
radiotherapy. The study was carried out to look at the adequacy of 3-D CBCT,
effectively a slow CT, to verify tumour motion.
Materials: Patients were selected for 4-D scanning, using Varian Real time
Position Management (RPM) system, if tumour motion of > 1cm was seen
at simulation. An ITV was contoured using the MIP and radiotherapy wasplanned on the average intensity projection acquired from all the bins. Patients were treated with 20 daily fractions of 2.75 Gy over four weeks. 3-D
CBCT scans were acquired on a minimum of 4 occasions during radiotherapy and co-registered with the planning scan. Tumour coverage as seen in
the CBCT against the ITV on the planning scan and tumour match was assessed. For each patient, the RPM system was used to monitor the breathing
rate and amplitude during the planning CT and at each treatment, we havetermed this ’back up gating’.
Results: 19/20 evaluable patients from January to October 2010 had a tumour motion between 1-1.5cm. Observational analysis of the CBCT data
showed good match between the tumour and ITV drawn on the planningscan in 18 patients (94.7%). Segmental lung collapse was responsible forthe mismatch between the CBCT/planning scan in one patient who was thenre-planned. Soft tissue/tumour match gave systematic and random errors
ranging from1.8 to 2.1 mm and 1.6 to 2.6 mm respectively in the 3 translations. For most patients, the breathing amplitude remained the same during
treatment so the beam was not interrupted.
Conclusions: Tumour motion appears to be stable in majority of patientsduring radiotherapy. 3-D CBCT verification with ’backup gating’ is a confident way of monitoring tumour motion, where amplitude is <1.5cm, in theabsence of a 4-D CBCT. 3-D CBCT not only provides verification of inter andintrafraction motion but is able to identify changes in tumour position due tosegmental/lobar lung collapse during radiotherapy.
893 poster
NON-GATED F-18 FDG PET/CT FOR TARGET VOLUME DELINEATION IN STEREOTACTIC BODY RADIATION THERAPY (SBRT)IN PATIENTS WITH STAGE I NON-SMALL CELL LUNG CANCER(NSCLC) OR HYPERMETABOLIC OLIGOMETASTATIC LUNG LESIONS
M. Schmuecking1 , B. Klaeser2 , M. Toepfer3 , M. Malthaner4 , N. Blumstein1 ,M. Frueh5 , E. Born4 , J. O. Brömme1 , L. Plasswilm3 , T. Krause2 , D. M.
Aebersold1
1
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Radiation
Oncology, Bern, Switzerland
2
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Nuclear
Medicine PET , Bern, Switzerland
3
K ANTONSSPITAL S T. G ALLEN, Department of Radiation Oncology, St
Gallen, Switzerland
4
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Medical
Physics, Bern, Switzerland
5
K ANTONSSPITAL S T. G ALLEN, Department of Medical Oncology, St Gallen,
Switzerland
Purpose: By design, stereotactic body radiotherapy (SBRT) is applied tosmall treatment volumes, using fewer but significantly higher dose fractions,and steep dose gradients all of which act to maximize cell kill and minimize the risk of damage to the surrounding normal tissues. Using F-18
FDG PET/CT for staging, radiation therapy of locally advanced non-small celllung (NSCLC) without elective nodal irradiation (ENI) has a risk of mediastinal out-field recurrences of about 2% to 4.3%. Treating stage I NSCLC or
oligometastatic lung lesions by SBRT, it is a prerequisite to exclude hilar andmediastinal lymph node involvement and distant metastases.
Materials: Inclusion criteria: Informed consent, histologically proven NSCLC
stage I or hypermetabolic oligometastatic lung lesions. Peripheral or central
localization, maximal tumor diameter of 45mm. Karnofsky index > 60%. Medically inoperable. Moving of the lung lesion during breathing less than 5mm asdetected by 4D-CT. Initial staging: whole body F-18 FDG PET/CT in radiation
treatment position, MRI of the brain. Optional for staging: F-18 FDG PET/CTof the lung in breath hold technique in radiation treatment position. Radiation
treatment planning: 4D-CT and angio-CT in radiation treatment position fortarget volume delineation. BodyFIX®vacuum cushions for comfortable, accurate and reproducible patient positioning during radiation treatment. Using

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L UNG CANCER

4D-CT for target volume delineation, a Boolean operation was used to sum
the multiple gross target volumes (GTV) delineated in diagnostic lung window to form an internal target volume (ITV). The planning target volume wasderived by a three-dimensional isotropic expansion of the ITV by 5mm to account for both microscopic extension and daily setup errors. Using non-gated
PET/CT (frame mode) for target volume delineation of the ITV the iso-line of
SUV 2.5 was used or the tumor/background algorithm as proposed by Nestle
et al. JNM 2005. For 16/22 lung lesions the prescription dose was 5 x 12
Gy, for 1/22 centrally located lung lesion the prescription dose was 5 x 10 Gy,
for the initial 5/22 lesions the prescription dose was 5 x 7 Gy. For all patientsthe prescription isodose was the 80% line (prescription line identical with theplanning target volume). Maximal time for follow-up: 21 months.
Results: For 20/22 lung lesions, the ITV derived by Boolean operation was
identical or smaller than the ITV derived by non-gated PET, in 2/22 lesionsof patients with stage I NSCLC bigger due to spiculae as seen in the diagnostic lung window. So far, no metabolic in-field recurrences were detectedby PET/CT during follow-up. One out-field recurrence was detected in hilar
and mediastinal lymph nodes 12 months after SBRT, one patient developed
a singular bone metastasis 18 months after SBRT, both patients were treatedwith 5 x 7 Gy (BED < 100 Gy). No treatment related deaths occurred and no
grade III/IV toxicities.
Conclusions: Our preliminary data suggest that in addition to high levels of
local control, SBRT delivery results in low rates of treatment-related toxicity.
However, SBRT delivery of 5 x 7 Gy (BED < 100 Gy) covers insufficiently thearea of microscopic extension beyond the GTV which may lead to in-field orout-field recurrences. Non-gated F-18 FDG PET/CT in radiation treatment
position is helpful for the ITV delineation of lung lesions and may be used toevaluate the magnitude of the daily setup errors prior to radiation treatment.

896 poster
RADIATION THERAPY OF NON-SMALL CELL LUNG CANCER WITH
DOSE ESCALATION ON COBALT 60 GAMMA UNITS. FOUR YEARSRESULTS
V. Sotnikov1 , G. Panshin1 , M. Ilin1 , A. Ivashin1
1
RUSSIAN S CIENTIFIC C ENTER OF R OENTGENOLOGY, Moscow, RussianFederation

894 poster
PALLIATIVE RADIOTHERAPY FOR NON SMALL CELL LUNG CANCER: A SURVIVAL ANALYSIS OF TWO FRACTIONATION REGIMESZ. Tasigiannopoulos1 , K. Geropantas1 , S. Loo1 , T. V. Ajithkumar1 , T.
Roques1 , C. Martin1
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, Departmentof Oncology, Norwich, United Kingdom

1

Purpose: To compare the overall survival of patients with non small cell lungcancer (NSCLC) treated with two different fractionation regimes of high-dose
palliative thoracic radiotherapy
Materials: A total of 128 patients with lung cancer who received palliative
thoracic radiotherapy between February 2003 and February 2009 were identified from our database. 107 patients had biopsy confirmed NSCLC, while
21 (16%) were not biopsied. They were divided into two groups based on
the number of fractions. Group 1 (57 patients) comprised 35 patients treatedwith 39 Gy in 13 fractions and 22 patients who received 36 Gy in 12 fractions
over 2.5 weeks. Group 2 (71 patients) included patients treated with 6 fractions twice-weekly over 3 weeks of whom 51 received a total dose of 27 Gy,
19 received 30 Gy and 1 received 36 Gy. Decisions regarding fractionation
schedule were made at the discretion of the treating physician. We compared the overall survival of these two groups of patients and studied various
prognostic factors
Results: There were 85 males and 43 females. Only 4 patients were aliveat the time of analysis. Median follow-up for the entire group was 8 months.
Patient characteristics, treatment details and survival outcome for the twogroups are summarized in table 1.

Conclusions: There was no difference in the median overall survival between patients with NSCLC treated with the two different fractionation schedules of palliative thoracic radiotherapy at our institution. However, subset
analysis has shown that patients who responded to chemotherapy had a prolonged survival with 12-13 fractions compared with 6 fractions (21.5 months
vs. 13.9 months p=0.02). The overall survival of patients who had nochemotherapy or without any response to chemotherapy was similar with both
fractionation regimes, suggesting that 6 fractions can offer a convenient treatment without compromising clinical benefits. Further analyses are being doneto evaluate the role of other prognostic factors
895 poster
PILOT STUDY TO DETERMINE SYSTEMATIC UNCERTAINTITIES IN
STEROTACTIC LUNG RADIOTHERAPY.
M. Nuñez Fernandez1 , A. Navarro-Martin1 , M. D. M. Arnaiz1 , J. M. Sole1 ,R. De Blas Pinol2 , R. Rodriguez3 , V. Navarro4 , F. Guedea5
1
I NSTITUT C ATALÀ D ’O NCOLOGIA, Department of Radiation Oncology,
L’Hospitalet de Llobregat, Spain
2
I NSTITUT C ATALÀ D ’O NCOLOGIA, Department of Medical Physics andRadiation Safety, L’Hospitalet de Llobregat, Spain
3
I NSTITUT C ATALÀ D ’O NCOLOGIA, Accelerator Department, L’Hospitalet de
Llobregat, Spain
4
I NSTITUT C ATALÀ D ’O NCOLOGIA, Clinical Trials and Statistics Unit,
L’Hospitalet de Llobregat, Spain
5
H OSPITAL DE B ELLVITGE P RINCEPS D ’E SPANA, Department of Radiation
Oncology, Barcelona, Spain
Purpose: To determine systematic error in Stereotactic Lung Radiotherapy(SLRT) patients treated under cone-beam computed tomography (CBCT) image control.
Materials: We analyzed 20 patients enrolled in a phase II trial for Sterotactic Lung Radiotherapy . Fifty four Grays are administered in three fractions
18Gy per fraction in peripherically located tumours. Immobilization system isbased in vacuum mattress. All patients underwent a zero session to evaluate
possibility of gantry-patient collisions. CBCT image control is performed ineach session to do soft tissue registration for internal target volume. Couchmovement for positional adjustment is registered in each session.
Results: Positioning data form 60 CBCT scans were analyzedLateral mean
adjustment registered was 0.5 cm range (05-1.20), vertical mean adjustment
0.66 cm (0,30-1.79) and longitudinal mean adjustment 0.33(1.7-0.29). No
relationships between collisions or larger displacements were found. A larger
displacement trend was found in the third session on the three dimensions.
Conclusions: Several guidelines have been published this year in SLRT, but
no agreement in immobilization system or image control movement has been
established. Main concern is that these patients have physical impediments
and a single vacuum mattress system is not the best method in these patientsand this larger displacement in the third session , in our opinion means thatan extra immobilization system should mandatory in these procedures.

Purpose: The high dose radiation therapy is used for numerous tumor sites,
including lung cancer. It demands expansive modern equipment and rarely
realized on Cobalt 60 gamma units. The purpose of this work was to evaluate
the toxicity and long term results of telegamma therapy of peripheral nonsmall cell lung cancer (NSCLC) with escalation of daily dose (3-4Gy) andtotal dose 60Gy.
Materials: Between January 2003 and September 2009 we intend to treat
46 patients age 45-81 years (median age 68) with peripheral NSCLC (stage
IA-7, stage IB-13, IIB-9, IIIA-5, IIIB-7, stage IV -5 patients), not suitable forsurgery due to stage or severe cardiac and/or lung comorbidities. All cases
are morphologically proven (epydermoid cancer 20, adenocarcinoma 8, others 8). Twelve patients received 2-4 cycles of neoadjuvant chemotherapy
After CT-based 2-D planning all the patients were irradiated on Cobalt 60
gamma units. Tumor and involved lymph nodes irradiated separately. The tumor motion was determined by roentgenoscopy on simulator and add to PTV.
Gross tumor volume + 1cm of surrounding lung tissue were included in PTV.
In order to minimize MLD two fields with wedges were typically used, as in
the most of the cases the tumor was localised near the chest wall or directly
invade it. The daily dose 3-4Gy (specified at 90% isodose) was given 5 times
a week. The total dose for tumor was 60Gy (α/β =3, EQD2=72-84Gy), thetotal dose for involved lymph nodes was 39Gy (EQD2=47Gy).
Results: 44 (96%) patients completed the full course of irradiation and were
included in analysis. In two cases the irradiation was finished prematurely
due to exacerbation of ischemic heart disease. In 6 cases the irradiation wasinterrupted due to esophagitis. According to RESIST criteria, after the radiation therapy the complete regression of the tumor was seen in 12 patients(27,3%), partial regression of the tumor was seen in 18 patients (40,9%), stabilization in 14 patients (31,8%). Pulmonitis grade II was diagnosed onlyin 7 patients (15,9%) during the next 3 months after the radiation therapy
and in all cases resolved successfully. Local changes of lung tissue density were revealed radiologically in all patients and are more sever in nonsmoking patients. No patients experienced shot-term or long-term toxicity
grade 3-4 according to RTOG criteria.Disease-specific survival for all group:
1 year - 87,2±5,4%, 4 years 34,1±10,0% (stage IA,IB - 93.3±6,2% and56,0±15,9%, stage IIB-IV - 81,8±8,2% and 22,5±12,0%).Survival without
infield progression for all group: 1 year 82,4±6,3%, 4 years 57,9±11,2%(T1-2: 1year - 91,7±5,5%, 4 years - 69,9±10,5%).Overall survival for allgroup: 1 year 79,9±6,4%, 4 years 30,1±9,0% (stage IA,IB - 92,9±6,4%
and 55,7±15,9%, stage IIB-IV - 69,7±9,4% and 17,7±9,8%).
Conclusions: Radiation therapy of the peripheral non-small cell lung cancer
with escalation of daily dose up to 3-4Gy (60Gy total dose) can be safely performed on traditional Cobalt 60 gamma units. About half of the patients withearly stage NSCLC are probably cured. Comparing with classic fractionation
this regimen decrease the period of irradiation from 40 to 28 days, and thenumber of procedures from 30 to 20, so more patients can be treated on thesame equipment with more chances not only for local cure, but for long term
survival.
897 poster
SBRT FOR MEDICALLY OPERABLE AND INOPERABLE EARLYNSCLC: MARKOV INSIGHT FOR OPTIMAL PATIENT SELECTION
A. Louie1 , G. Rodrigues2 , M. Hannouf3 , D. Palma1 , S. Senan4
1
L ONDON R EGIONAL C ANCER P ROGRAM /LHSC, Radiation Oncology,
London, Canada
2
L ONDON R EGIONAL C ANCER P ROGRAM /LHSC, Epidemiology andBiostatistics, London, Canada
3
U NIVERSITY OF W ESTERN O NTARIO, Epidemiology and Biostatistics,
London, Canada
4
VU U NIVERSITY M EDICAL C ENTER, Radiation Oncology, Amsterdam,
Netherlands
Purpose: Randomized clinical trials evaluating the role of SBRT in stage I
NSCLC are now ongoing but these are not expected to complete accrual in
the short-term. We therefore developed Markov models, which are tools forstatistical modeling, to simulate both short term and long-term outcomes indifferent sub-groups of patients presenting with this disease.
Materials: We constructed a Markov model to simulate the clinical historyof (i) medically operable stage I NSCLC patients treated with either SBRTor lobectomy, and (ii) patients aged ≥75 years with COPD who undergo
SBRT or best supportive care (BSC), both for a 5-year timeframe. Clinical parameters for recurrence rates and Markov state utilities for appropriate AJCC
stages of NSCLC were extracted from the literature and adapted to monthly
time intervals. For medically operable patients, age- and sex-specific rates
of death from all other causes were extracted from standard life tables andS 345

varied according to smoking habit. Surgical outcomes from the model werecompared to Adjuvant! Online (AO). Elderly COPD patients were stratified
into 4 classes according to T stage (1 vs. 2) and COPD GOLD score (I-II vs.
III-IV). The 4 patient classes were: I (T1, GOLD I-II), II (T2, GOLD I-II), III (T1,GOLD III-IV), and IV (T2, GOLD III-IV). We report various treatment strategy
overall and quality adjusted survival outcomes stratified by age, sex, smoking history, COPD, and T-stage. Sensitivity analyses on the quality of life of
SBRT, treatment-related death, and proportion of patients with recurrent disease receiving radical treatments were performed to determine thresholds fortreatment modality preference.
Results: For surgical patients, the 5-year overall survival, cancer specific survival, and other causes of death as predicted by our model correlated closelywith AO, ranging from 0.0% to 3.8%. Differences between surgery and SBRT
ranged from 2.2% to 3.0% in 5-year overall survival and 0.07 to 0.09 in quality adjusted life years, both in favor of surgery. The SBRT utility threshold forpreferring SBRT over surgery was 0.90. Outcomes were sensitive to the quality of life after SBRT, the proportion of local and regional recurrences treatedwith radical versus palliative treatments, and the surgical and SBRT treatment
related mortalities. For high risk patients, our model predicted for a benefit
in 5-year overall survival of 4.0% to 38.2% and 8.8 to 17.4 quality-adjusted
life months in favor of SBRT over BSC for the 4 classes. Outcomes were notsensitive to the disutility associated with SBRT or disease progression.
Conclusions: Markov modeling suggests that withholding SBRT from patients based upon their age and/or COPD severity appears to be unjustified.
In addition, SBRT may offer comparable overall survival and quality adjusted
life expectancy in operable cases, as compared to surgical resection
898 poster
STEREOTACTIC BODY IRRADIATION WITH HELICAL TOMOTHERAPY FOR T1-T2 NSCLC OR LUNG METASTASES FROM OTHERPRIMARY SITES
M. Marcenaro1 , L. Belgioia2 , E. Mantero2 , D. Doino2 , D. Agnese2 , S.
Vagge1 , S. Agostinelli3 , F. Cavagnetto3 , S. Garelli3 , M. Gusinu3 , M.
Zeverino3 , R. Corvò1
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Radiation Oncology,
Genova, Italy
2
R ADIOTHERAPY S CHOOL U NIVERSITY, Radiation Oncology, Genoa, Italy
3
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Medical Physics,
Genova, Italy
Purpose: To evaluate feasibility and preliminary results in pts with NSCLC orlung mts from different primary sites treated with SBRT.
Materials: Between August 2009 and December 2010, 33 pts with T1-T2
primary NSCLC and no more than 4 mts from different primary sites underwent SBRT at the Radiation Therapy Department, National Cancer Institute,Genoa. SBRT was performed with helical Tomotherapy (HT). Pts were treatedwith different fractionation schemes depending on T stage, tumor location inside the chest (central/peripheral), presence of lung primaries or metastatic
disease: all but 4 pts received a planned BED> 100Gy10 according to recent
literature recommendations. In the first 4 pts SBRT with BED<100Gy10 was
allowed to assess treatment tolerance. Our policy was to treat T1 peripheral
tumors with 48Gy/4fx, T2 peripheral tumors with 52Gy/4fx, any T1-2 central
tumors with 50Gy/5fx for the higher risk of major toxicity, mts and previously
irradiated pts with 60Gy/8fx. In 7 out of 33 pts a simulation CT/PET was
performed. In 29 of 33 pts a diagnostic CT/PET was available.
Results: Median age of the 33 pts was 73 yrs (range 57-86). Median follow
up was 6 months (range 1-14). Pts stage was as follow: 13 pts (40%) with T1
NSCLC, 4 pts (12%) with T2a NSCLC, 8 pts (24%) with local recurrence fromprevious NSCLC, 8 pts (24%) with up to 4 metastatic lung localization fromeither NSCLC or other primary location. 16 and 12 pts had peripheral andcentral lesions, respectively. 5 pts had both central and peripheral disease.
7 pts have had previous chest irradiation. Histology was available in 19/27
pts with lung cancer, 13 (48%) of those had adenocarcinoma, 5 (18%) had
squamous cell carcinoma and 1 (4%) had undifferentiated carcinoma. In theremaining 8 pts (30%) diagnosis of lung cancer was based on CT or CT/PET
findings. 6 pts were diagnosed with mts from previous bladder, colon, rectal,
uterus or gastric primaries. Of the 33 pts treated with SBRT, 13 (40%), 2 (6%),
7 (21%), 7 (21%) and 4 (12%) were given 60Gy/8fx, 52Gy/4fx, 50Gy/5fx,
48Gy/4fx and different fractionation schemes, respectively. SBRT was welltolerated in all 33 pts. No or mild acute toxicity (dysphagia, dyspnoea, fatigue)
was recorded. In 3/33 pts (9%) lung fibrosis were detected on a follow up CT
scan. Response to treatment was assessed with CT and/or CT/PET: 7/33
pts (21%), 4 pts (12%) and 11 pts (34%) had complete response, partial
response and stable disease, respectively. 9 (27%) pts had local or systemic
progression. We recorded one cancer related death and one death due tonon-oncologic cause.
Conclusions: With the limit of the short follow up, these preliminary data
seem to confirm that SBRT by HT for pts with small and few lung localizations
from lung or other cancer sites is feasible, well tolerated and gives good results in terms of local control. More pts and a longer follow up are needed toassess the clinical benefit of the adopted fractionation schedules.

S 346

LYMPHOMA

L UNG CANCER

899 poster
STEREOTACTIC BODY RADIATION THERAPY FOR INOPERABLE
NSCLC WITH STAGE I-II: A MONO-INSTITUTIONAL RETROSPECTIVE STUDY
S. Masciullo1 , F. Casamassima1 , C. Menichelli1 , I. Bonucci1 , L. Masi1 , R.
Doro1
1
U.O.R ADIOBIOLOGIA C LINICA U NIVERSITÀ DI F IRENZE, Firenze, Italy
Purpose: Stereotactic body radiation therapy (SBRT) is becoming a standard
treatment for non-small cell lung cancer (NSCLC). We report our experiencein this setting in terms of survival, local control, modality of progression andtoxicity.
Materials: We reviewed the medical records of 63 inoperable patients withcito/histological diagnosis of NSCLC (29 adenocarcinomas, 20 squamous
cell, 12 others, 2 not performed) treated by SBRT in our Institution between
2001 and 2010. The patients characteristics were: female=11, male=52;
median Karnofsky PS=90 (60-100); median age=78 (54-86); stage IA=20,
IB=25, IIA=2, IIB=16; N1=7; median tumor size=3 cm (1.5-7); peripheral localization 50, central 13; BPCO moderate-severe in 35 patients. For the majority of cases the GTV was delineated on two contrast-enhanced CT data
sets acquired at the end of inspiration and expiration and the contours fused
to obtain an ITV. Median PTV was 41 cc (4.8-166). Prescription dose ranged
from 26 to 36 Gy (median 30) in 1-4 fractions (median 3). The dose was prescribed at isocenter and PTV covered at least by 90% isodose. 25 patientswere treated with SRS in single fraction. Cone-Beam CT in 38 cases andBody Frame in 25 were used for setup corrections and isocenter verification.
A 6-MV LINAC equipped with dynamic mMLC was utilized for dose delivery.
CTCAE v.4 and modified RECIST criteria were used for toxicity assessment
and response evaluation.
Results: With median follow-up of 16.2 months (2-83) 41 patients are alive (6NED). 3-years overall and cancer-specific survival from the end of radiotherapy were 51% and 62% for stage I and 46% and 53% for stage II, respectively.
Among 56 evaluable patients with at least one radiographic follow-up, actuarial 3-years local control was 63%, without differences between SRS and SRT.
Stratifying for three BED levels (<70, 70-90, >90 Gy10), the better local control was obtained with BED > 90 Gy10, although statistically non significant
owing to the small number of patients enrolled. Overall, there were 4 nodal
failures and 7 distant failures. Nodal recurrence without systemic progression
occurred in one patient. 3-years PFS (local, locoregional and systemic) was
46.4%. No acute or late toxicity of grade ≥2 was observed.
Conclusions: Our results are in line with those reported in literature andsupport the role of SBRT as a very effective treatment option for inoperable
early-stage NSCLC patients. Locoregional and distant progression rates suggest the utility of systemic therapies for selected patients. Nodal recurrence
alone occurred just in one patient, confirming the safe avoidance of elective
nodal irradiation for early NSCLC stages.
900 poster
STEREOTACTIC BODY RADIATION THERAPY FOR NEW LUNGCANCER ARISING AFTER PNEUMONECTOMY FOR BRONCHOGENIC CARCINOMA.
A. Testolin1 , C. Baiocchi1 , M. S. Favretto1 , S. Galuppo1 , S. Cora2
1
O SPEDALE S AN B ORTOLO, Department of Radiation Oncology, Vicenza,
Italy
2
O SPEDALE S AN B ORTOLO, Department of Medical Physics, Vicenza, Italy
Purpose: Curative treatment for new lung cancer after pneumonectomy (P)is challenging. Repeat surgery often is contraindicated because impaired pulmonary reserve or comorbidity. In recent years numerous studies have shownthat Stereotactic Body Radiation Therapy (SBRT) is an effective and well tolerated treatment for inoperable stage I lung tumor. However only limited data
exist on the tolerance and outcomes of curative radiotherapy in patients (pt)
who develop a new lung cancer after P. In this work we evaluated the clinicaloutcomes after SBRT for such pt.
Materials: From January 2007 to June 2010 10 pt, who developed a second
lung cancer in the controlateral lung after P, were treated with SBRT. The median time from P to new primary was 3.6 years (y) (1-9.8). Seven lesions werescored as metachronous primary stage I tumor and 3 as solitary mestastasis because the disease free interval between cancers was < 2 years. The
median maximum tumour diameter was 2.1 cm (1 4.5). The planning target
volume (PTV) consisted of the tumor volume, including all respiration motion
derived from 4DTC scan, plus an addition safety margin of 4-5 mm. The
median PTV was 20.7 cm3 (2.4-101.2). Treatment planning was performed
with Multiplan System treatment planning (version 2.1.0, Accuray Inc., Sunnyvale, CA) and resulted in a median of 117 non-coplanar beams (84-197).
All pt were treated using a CyberKinife System with dynamic tracking system.
Each treatment lasted about 60 minutes. Five pt were treated with a single
fraction (f) of 26 Gy and 5 with fractionated schemes (3 pt with 3 f of 10 Gy,
1 pt with 3 f of 15 Gy 1 pt with 4 f of 10 Gy). The dose was prescribed to the
80% isodose line. Median FU was 15 months (m) (6-32).
Results: local recurrence occurred in 2 pt, regional recurrence in 1 pt and distant metastases in 2 pt. Four pt died for disease progression at 24,26,31,32

m (local 1 pt, local and distant 1 pt, regional 1 pt and distant 1 pt). One pts
died of intercurrent disease at 11 m. Five pt are alive and without evidenceof disease at 18,12,11,7 and 6 m. Kaplan-Meier local control at 1 an 2 y wasrespectively 87.5 and 58.3% . Overall and cancer specific survival at 2 y wererespectively 65% and 75 %. Treatment was well tolerated. Early side effects
were limited to fatigue in 3 pts (grade I-II). No clinically symptomatic pneumonitis was observed. Subjective symptoms of increased dyspnoea during
FU occurred in 2 pts but without the need for oxygen therapy. Asymptomaticradiation induced lung fibrosis was detected in 3 pt.
Conclusions: SBRT appears to be a safe and minimally invasive modality fortreating pt with a second lung tumor in the controlateral lung after P for a bronchogenic carcinoma. The use of more aggressive treatment, with biologicaleffective dose (BED) of > 100 Gy10, can further improve upon these results.
Longer FU will be required to fully establish toxicity as well as probability of
local failure.

brain. Optional staging: F-18 FDG PET/CT of the lung in breath hold technique in radiation treatment position. Restaging after SBRT was done by CT
or F-18 FDG PET/CT. Maximal time for follow-up: 21 months, range 3 to 21
months. Median time for follow-up: 9 months.
Results: Eighteen patients were evaluated. Nine out of 18 patients (50%) received an additional breath hold acquisition of the lung. In 2 out of 9 patients(22%) additional lesions were detected (hilar lymph nodes, mediastinal lymph
nodes, pulmonary lesions) excluding them from SBRT. Due to a reduced lungfunction and health condition these PET positive lesions of these two patientswere not histologically proven, however follow-up studies by CT or F-18 FDG
PET/CT show, that these lesions were correctly staged and not false positive lesions. So far, no in-field recurrences were detected by PET/CT or CT
during follow-up after SBRT. One out-field recurrence occured in hilar andmediastinal lymph nodes 12 months after SBRT, and one patient developed asingular bone metastasis 18 months after SBRT; both patients did not receive
the breath hold acquisition.

901 poster
THE "PTV LIE" WHEN USING ANALYTICAL ANISOTROPIC ALGORITHM (AAA) COMPARE TO THE PENCIL BEAM (PB) ALGORITHM
A. Meirovitz1 , A. Wygoda2 , M. Wygoda2 , J. Feldman1
1
H ADASSAH - H EBREW U NIVERSITY M EDICAL C ENTER, Oncology andRadiotherapy, Jerusalem, Israel
2
H ADASSAH U NIVERSITY H OSPITAL, Oncology and Radiotherapy, EinKerem Jerusalem, Israel
Purpose: The Analytical Anisotropic Algorithm (AAA) implemented in the
Eclipse treatment planning system is a 3D algorithm that models the primary
photons, contamination electrons and the transport electrons released dueto heterogeneities. The purpose of this study is to compare the performanceof two algorithms, the AAA and the Eclipse Pencil Beam (PB), in estimatingdose volume histograms (DVH) for planned tumor volume (PTV) and organs
at risk in Lung.
Materials: A phantom model, simulating a lung tumor in several positions
was used. A water balloon was marked gross tumor volume (GTV) and a
CTV was established to cover all GTVs. Margins of 0.5cm were set for the
PTV. Treatment plans were created using both algorithms. In addition, we
compared 20 patient treatment plans using both algorithms. CTVs were established and corrected for breathing motions using three CT simulations (inspirum, expirium and free breathing). The DVH of the GTV, PTV, and Lungs
were compared between these two algorithms.
Results: In all cases the AAA algorithm revealed lower dose coverage to
the PTV. However the GTV coverage was as prescribed for both algorithms
independent to GTV position. In the PB algorithm there was an underestimation of the volume receiving low doses (<~20Gy) and an overestimation of
the volume receiving high doses (>~20Gy). The amount of the misestimating depends on the tumor size, number of fields and gantry angles. These
differences were up to 40%.
Conclusions: A PTV coved by 95% the prescribed dose calculated with PB
and recalculated with AAA results in insufficient dose coverage due to air in
the PTV. However the GTV will receive the prescribed dose independent tobreathing motions. This we called the "PTV lie". The "PTV lie" phenomena
should question the way we prescribe dose to lug tumors when using AAA.
The one point on the DVH curve, V-20 is used to guide dose constrains tolung and is similar in both algorithms, while there are big differences between
the DVH curves. Therefor it may be necessary to reestablish new dose constrainers for lung based on more than one point on the curve.
902 poster
WHAT IS THE ADDITIONAL ROLE OF THE BREATH HOLD ACQUISITION USING F-18 FDG PET/CT IN STAGING NON-SMALL
CELL LUNG CANCER (NSCLC) PRIOR TO STEREOTACTIC BODY
RADIOTHERAPY (SBRT)?
M. Schmuecking1 , B. Klaeser2 , M. Frueh3 , M. Toepfer4 , M. Malthaner1 , E.
Born1 , J. O. Brömme1 , L. Plasswilm4 , T. Krause2 , D. M. Aebersold1
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Radiation
Oncology, Bern, Switzerland
2
U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Department of Nuclear
Medicine PET , Bern, Switzerland
3
K ANTONSSPITAL S T. G ALLEN, Department of Oncology and Haematology,
St Gallen, Switzerland
4
K ANTONSSPITAL S T. G ALLEN, Department of Radiation Oncology, St
Gallen, Switzerland
1

Purpose: When treating stage I NSCLC with stereotactic body radiotherapy(SBRT), it is crucial to exclude hilar and mediastinal lymph node involvementand distant metastases. We evaluated the role of the breath hold techniquein addition to whole body acquisition.
Materials: All patients in this retrospective analysis had histologically provenstage I NSCLC, peripheral or central localization, maximal tumor diameter of
45mm, Karnofsky index > 60% and were medically inoperable. Initial staging: whole body F-18 FDG PET/CT in radiation treatment position, MRI of the

S 347

months. Patients with Primary Cutaneous Diffuse Large B-cell Lymphoma(PCDLBL) and MF histology had poorer overall survival compared to otherhistological subtypes. Performance status correlated closely with overall survival.There was no significant difference in the local relapse free survival rates
between Low (BioEqDose <20Gy) and High dose radiotherapy (p = 0.476).
There was a higher rate (20.7%) of local recurrence noted in patients with
PCDLBL compared to other histological subtypes.
Conclusions: Low dose radiotherapy is an excellent treatment of local control of cutaneous lymphomas giving a high local control rate (91.14%) andconvenient dose delivery. It can also be used to with good effect to salvage
local failures. Certain histological types like PCDLBL may require more aggressive treatment for better control.
904 poster
BEXXAR PROTOCOL CP98-020 :RADIO-IMMUNOTHERAPYRESULTS WITH I-131 LABELED ANTIBODY IN PATIENTS WITH
FOLLICULAR NON-HODGKIN’S LYMPHOMA : MEDIAN 5-YEAR
RESULTS IN 70 CASES
I. Shalaby1 , R. Mark2 , R. Akins2
1

J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department of
Hematology and Academic Unit of Clinical and Molecular Oncology,
Lubbock, Texas, USA
2
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, Texas, USA

Conclusions: Our very preliminary results show, that the breath hold acquisition may be of added value to correctly stage patients with stage I NSCLC
suitable for SBRT.

Lymphoma
903 poster
A STUDY OF OUTCOMES OF LOCAL RADIOTHERAPY FORPRIMARY CUTANEOUS LYMPHOMAS.
A. Haridass1 , H. Wong2 , I. Syndikus1 , V. Ramani1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Clinical Oncology, Bebington,
Merseyside, United Kingdom
2
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Medical Statistics, Bebington,
Merseyside, United Kingdom

Purpose: Non-Hodgkin’s Lymphoma (NHL) B-Cell subtype, is generally very
sensitive to Chemotherapy and Rituxan. In patients who have developed refractory disease, the course of disease is usually rapidly fatal. Many NHL
B-Cells express CD-20 Antigen. Such patients may be candidates for Radioimmunotherapy (RIT) with tositumomab murine monoclonal antibody conjugated with I-131, which can bind to CD-20 expressing cells with potentiallylethal effects. We present results in 69 patients treated according to theBexxar CP98-020 Protocol.
Materials: Initially, candidates for Bexxar CP98-020 Protocol, were patientswith NHL expressing CD-20 which had become refractory to Chemotherapy
and Rituxan. Since 2006, seven patients have received primary treatment
for NHL with RIT. Eligibility criteria included Platelet count > 100,000, lessthan 25% involved bone marrow, and no kidney dysfunction. In addition, thepatients could not be pregnant or breast feeding. Between 2001 and 2010,
70 patients received I-131 labeled Antibody. The total body dose was 75 cGyfor Platelet counts > 150,000 and 65 cGy for Plt 100-150,000. Activity ranged
from 60 mCi to 120 mCi.
Results: Median follow-up was 60 months (range 6-120 months). The response rate was 74.3% (52/70), with complete response achieved in 25.7%(18/70) of the patients. Median progression free survival was 16 months.
All seven patients treated with primary RIT remain free of recurrence, withfollow-up periods ranging from 32-68 months. Toxicity was moderate, with
7.1% (5/70) of patients experiencing profound (Platelets < 10,000) thrombocytopenia, which was prolonged, lasting more than 20 weeks. There wereno bleeding complications, and no patient required a transfusion. For the remaining 65 patients, Plt counts decreased mildly for 4-6 weeks following RIT,
and then returned to normal values by 10-20 weeks.
Conclusions: RIT has yielded promising 5 year results in NHL patients refractory to Chemotherapy and Rituxan. Toxicity has been acceptable. RIT
may be considered for first line treatment in some cases of NHL.
905 poster

Purpose: Background:Cutaneous lymphomas are a rare and heterogeneous group of malignancies with a low incidence of 0.4 per 100,000 per year
but a high prevalence due to high survivorship. Although incurable in most instances standard palliative treatment for this group uses low dose radiotherapy produces lasting CR in individual lesions against a background of disease
relapsing at other sites over a long time frame (months).Aims and objectives:To report outcomes of cutaneous lymphomas patients treated with local radiotherapy.The primary end point was local relapse free survival (LRFS);
secondary endpoints included LRFS after salvage radiotherapy, overall survival and local control rates.
Materials: Data was extracted from case records for patients who had beentreated with radiotherapy between 2002 and 2008. Data on histological type,staging, radiotherapy doses used, sites treated, systemic treatment, and outcomes of treatment were obtained and analysed.
Results: 39 Male patients and 28 female patients with the median age of
67 were treated for this condition with a total of 315 treatment episodes. B
cell lymphomas constituted 53% of the diagnoses and 44% were T-cell lymphomas mainly mycosis fungoides (MF). A majority (91%) were treated withlow dose radiotherapy with 8Gy in 1-2 fractions being the commonest dose(76%),delivered using Kilovoltage X-rays (91%).64% of the patients are alive
without relapse, a further 12% alive with disease and 23% dead; 9% due toprogressive disease. The median LRFS was 14.3 months with a range of 0.3
to 96 months. There were 28 local relapses (8.86%) of which 26(93%) weretreated with salvage radiotherapy. The median dose and fractionation used
was 8Gy/2#. 23(88.5%) patients were successfully salvaged with radiotherapy achieving a median LRFS of 6.67months.Median overall survival was 38

CEA/ABVD: A NEW REGIMEN CHEMOTHERAPY FOR HODGKIN’SLYMPHOMA.
I. Albitskiy1 , P. Datsenko2 , V. Sotnikov1 , Y. Melnik1 , P. Podolski1
1

RSCRR, Department of Radiation Oncology, Moscow, Russian Federation
RSCRR, Department of Radiation Oncology
Molecular Radiation
Sciences, Moscow, Russian Federation

2

Purpose: Today more than 95% of patients with Hodgkin’s lymphoma (HL)in early stages and in advanced stages 85-90% can be cured. ABVD which
nowadays is accepted as "gold standard" for the treatment of advanced HL.
The CEA/ABVD (lomustine (CCNU), etoposide, adriamycine, bleomycine,
vinblastine and dacarbacine) regimen was developed to improve treatment
results by addition of etoposide and lomustine to chemotherapy ABVD (adriamycine, bleomycine, vinblastine and dacarbacine).
Materials: One hundred seven patients with HL stage II - IV according to
the Ann Arbor classification were treated with CEA/ABVD regimen, 12 patients with early, and 39 patients with intermediate and 56 patients with unfavorable prognostic group (GHSG). The CEA/ABVD chemotherapy regimen(baseline) was introduced in 2000 has been previously reported. Chemotherapy was given weekly for 13 weeks as follows: doxorubicin 25 mg/m2 on
weeks 1, 2, 4, 5, 8, 9, 12, and 13; bleomycin 10 mg/m2 (maximum dose, 15mg) and vinblastine 6 mg/m2 (maximum dose, 10 mg) and dacarbazine 375
mg/m2 on weeks 1, 2, 5, 8, 9, and 13; lomustine 80 mg/m2 and etoposide 100
mg/m2 for three days on weeks 4, and 12. Sixty patients were treated with

S 348N ORMAL TISSUE

LYMPHOMACEA/ABVD regimen (baseline). Bloc-chemotherapy CEA/ABVD regimen was
introduced in 2007. Chemotherapy was given weekly for 17 weeks as follows:
doxorubicin 25 mg/m2 on weeks 1, 3, 5, 7, 9, 11, 13, 15, and 17; bleomycin
10 mg/m2 (maximum dose, 15 mg) and vinblastine 6 mg/m2 (maximum dose,
10 mg) and dacarbazine 375 mg/m2 on weeks 1, 5, 7, 11, 13, and 17; lomustine 80 mg/m2 and etoposide 100 mg/m2 for three days on weeks 3, 9, and
15. Forty seven patients were treated with bloc-chemotherapy CEA/ABVD
regimen. Eight patients were treated with IFRT or INRT, 45 with EFRT, 54
with STNI.
Results: After a median observation time of 4.1 years, the rates for freedom
from treatment failure (FFTF) are 95.5 percent, and for overall survival (OS)93.7 percent for regimen CEA/ABVD. There have been no deaths among
the 51 patients in groups with early and intermediate prognosis, one relapse
has occurred (1.9%). Two relapses and one death (HL) have occurred in
the group of 20 patients with stage II bulky mediastinal disease, one relapse
and four deaths in the group of 38 patients with stage III-IV disease (1 HL,
1 hematologic toxicity, 2 cardiovascular disease; age>45 years). In grope
CEA/ABVD (baseline) with a median follow-up of 6.6 years, 3 of 60 patientswere relapse HL, rates for FFTF are 94.7 percent, OS 91.1%. In grope
bloc-chemotherapy CEA/ABVD with a median follow-up of 1.9 years, 1 of
47 patients were relapse HL, rates for FFTF are 96.4 percent, OS 100%.
In grope with STNI two relapse has occurred (3.7%), with EFRT 2 (4.4%),
IFRT or INRT 0%.Acute Toxicity: one death has occurred in the group with
CEA/ABVD (baseline) to patient with hematologic toxicity grade 4 (male, 48
year; 1.7%). Myelosuppression constituted the major acute toxicity (107 patients). Thirty three patients had an ANC less than 500/µL (35.5%) and 15
patients had an ANC less than 100/µL (14%) at some time during chemotherapy. In the groups with CEA/ABVD (baseline or bloc) toxicity was tolerablewith WHO grade 3/4 leucopenia in 63.3% and 74.4% of chemotherapy cycles,
grade IV leucopenia 25% and 44.7%. Grade 3-4 anemias were observed in
13.3% and 25.5%, thrombocytopenia grade 3/4 recorded in 20% and 19.1%.
In grope with CEA/ABVD (baseline) G-CSF was routinely used after the initial
dose reduction or delay, a total of 25 patients received G-CSF. Dose reduction
was a total of 14 patients (23.3%), delay chemotherapy - 2 patients (3.3%),
1/2 course - 7 patients (11.7%). In grope with bloc-chemotherapy CEA/ABVDa total of 33 patients received G-CSF (72.2%). Dose reduction no was ingroup bloc-chemotherapy CEA/ABVD (0%), dose delay of 7 days - 1 patient(2.3%). Febrile neutropenia in the course of bloc-chemotherapy CEA/ABVDno complicated of combination chemotherapy injections. In contrast, febrileneutropenia (23.3% and 21.9%) were more frequent in CEA/ABVD (baseline).
Infection rate was 11.5% (CEA/ABVD (baseline) 11.6%; Bloc-chemotherapy
11.4%), pneumonia (1.7% and 2.3%), and hair loss 100%. In contrast, acutenausea (83.3% and 72.7%), gastrointestinal toxicity (8.3% and 2.3%), andpharyngeal toxicity (5% and 9.1%) were more frequent in CEA/ABVD (baseline). Two patients were hospitalized during or within 3 months of completing CEA/ABVD (baseline) with cardiovascular disease (3.3%), one of themdied. One death occurred in the group with CEA/ABVD (baseline) to patientwith fatal pneumonitis (1.7%). Late Toxicity: a 31-year-old woman developed
non-Hodgkin’s lymphoma orbit through 2.5 year after CEA/ABVD chemotherapy regimen (baseline). A 31-year-old man developed tuberculosis through2 year after CEA/ABVD chemotherapy regimen (baseline). With a medianfollow-up of 4.1 years, after CEA/ABVD (107 patients) no cases of a single second malignancy, secondary leukemia, myelodysplasia have been observed to date.
Conclusions: These data confirm that CEA/ABVD chemotherapy with
RT is highly effective in locally extensive and advanced Hodgkin’s disease.
It is most important to compare this approach with standard
doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy to determine whether CEA/ABVD with or without RT represents a therapeuticadvance.
906 poster
OCULAR TOXICITY AFTER 3D-CONFORMAL RADIOTHERAPY FOR
NON-HODGKIN ORBITAL LYMPHOMA
L. Vinante1 , C. Boso1 , F. Vianello1 , H. El Barbir1 , S. Aversa2 , D. Marino2 ,D. Fiore3 , G. Sotti1
1
I STITUTO O NCOLOGICO V ENETO, Department of Radiotherapy andNuclear Medicine, Padova, Italy
2
I STITUTO O NCOLOGICO V ENETO, Department of Oncology, Padova, Italy
3
U NIVERSITY OF PADUA, Department od Diagnostic Sciences and Special
Therapies, Padua, Italy
Purpose: The orbital Non-Hodgkin lymphoma (NHL) is a rare malignancy,
usually localized and low aggressive, which management requires the irradiation of whole orbital cavity. This involves structures, as lens, particularly
sensible to radiation effects. This single institution study wants to evaluate
the acute and late side effects of conformal 3D irradiation for primary NHL.
Materials: We retrospectively evaluated 59 consecutive patients (20 womenand 39 men, mean age 59 ± 16 yrs) with stage IEA NHL from 1986 to 2010.
The disease was localized in the left eye in 34 (58%) patients, in the right in 21(35%), bilateral in 4 (7%), and involved the orbit in 30 (51%), the conjunctiva
in 18 (31%) and other orbital structures in 11 (18%). All patients underwent
3D-conformal radiotherapy after diagnosis (by pathological or cytological examination), staging (haematological tests, total body CT, bone marrow biopsy,

orbital CT or MR) and in 4 cases after chemotherapy. The median dose was
30.6 Gy (range 30-40 Gy) with a standard fractioning (1.8 Gy per day) and
the PTV consisted of whole orbital cavity. The bolus (thickness 0.5-1 cm)
was used only in case of superficial localizations (25%). We described acuteand late toxicity incidence and calculated the risk factors for cataract, using
chi-square or Fisher test as appropriate.
Results: The mean follow up was 68.3 ± 55 months. It was performed byclinical and radiological examinations (total body CT, lymphatic stations US)
and by ophthalmic visits, every 46 months during the first 5 years and thenonce a year. The local control was obtained in 58 (98.3%) patients. According to the RTOG scale, the grade (G) 1 and 2 acute effects were 37% and
24% respectively, no G3-4 were observed in 39%. Thirty-six (61%) patients
had no late toxicity, 22(37%) presented low effects (G1-2) and only 1 (2%)
had retinopathy and bilateral cataract (G3). The table 1 reports the adverse
effects. The cataract developed in 20 (34%) patients 2-7 yrs after radiotherapy was the more common late effect. It was easily treated by surgery. We
considered as possible risk factors for cataract: age >60 yrs, Karnofsky performance status < 90%, total dose > 30.6 Gy, use of bolus and chemotherapy
association. Total dose > 30.6 Gy resulted significantly associated (p<0.005).
Cataract was developed in 13 of 24 patients (54%) treated with dose >30.6(median 36 Gy), in 7 of 35 (20%) with dose ≤ 30.6.

Conclusions: 3D conformal radiotherapy was effective and well tolerated,with low-grade acute and late toxicity, for patients with orbital lymphoma.
Cataract was the more frequent side effect, it was associated with a total
dose > 30.6 Gy and easily treated with surgery. Eyesight was well preserved.

not retain significance at multivariate analysis, but it is associated with better
OS when "short" and "long term" survivors are analyzed separately. Overall
median survival was 187 days; actuarial OS at 1 and 5 years was 42% and
5% respectively.
Conclusions: Age ≥ 60 years, normal immune status, good performancestatus are confirmed as important prognostic factors. High doses of RT andadherence to prescribed treatment are the most important predictive factors
related to RT treatment. RT alone, also hypofractionated, with doses > 46 Gy
can be considered in selected patients not eligible for radical treatment.
908 poster
RISK OF CARDIAC AND VALVULAR DISEASE AFTER MANTLE OR
INVOLVED NODE RADIOTHERAPY IN HODGKIN LYMPHOMA
M. Maraldo1 , M. Aznar1 , P. Brodin1 , P. Munck af Rosenschöld1 , P. M.
Petersen1 , I. R. Vogelius1 , L. Specht12
1
T HE F INSEN C ENTER - R IGSHOSPITALET, Copenhagen, Denmark2
C OPENHAGEN U NIVERSITY, Faculty of Health Sciences, Copenhagen,Denmark
Purpose: The risk of developing cardiac disease (CD) for long-term Hodgkin
lymphoma (HL) survivors after mediastinal radiotherapy (RT) is under debate,
as current data are, primarily, derived from patients treated with the outdated
Mantle Field (MF) technique.In this work, we compare doses to the heart
and four heart valves with Involved Node RT (INRT), the present standardof treatment, and MF. We also derive and compare the excess absolute risk
(EAR) of developing CD using both techniques.
Materials: We included 10 adolescents-young adults with clinical stage I-II
HL. All patients were treated with chemotherapy and INRT (30-36 Gy). For
each patient we simulated a MF, delivering 36 Gy.We derived a logistic doseresponse function for the 25 year risk of any CD and valvular disease (VD)
using published data from a HL cohort[1]. For each patient we estimated therisk of any CD and VD from the individual dose volume histogram and thedose-response function.
Results: For all 10 patients the mean heart dose was 4.9 Gy (range: 0.118 Gy) and 24.8 Gy (range: 18.6-28.8) with INRT and MF, respectively. For
mean doses to the individual valves see fig. 1.The mean EAR 25 years after
treatment was 0.8% (range: 0.4-3.5%) for CD and 0.04% (range: 0-2.46%)
for any VD with INRT. For MF the mean EAR was 6.6% (range: 6-10. 1%) for
CD and 8% (range: 2.7-14.4%) for any VD.

907 poster
PRIMARY CNS LYMPHOMA (PCNSL): A RETROSPECTIVE ANALYSIS OF PATIENTS TREATED WITH PALLIATIVE RADIOTHERAPY(RT)
M. Buglione1 , P. Borghetti1 , F. Trevisan1 , M. Maddalo1 , B. Bonetti1 , L.

909 poster
TOTAL MARROW IRRADIATION AS SELECTIVE BOOST MODALITY
AFTER CONVENTIONAL TBI FOR PATIENTS WITH ADVANCEDHEMOPOIETIC MALIGNANCIES UNDERGOING AN ALLOGENEICSTEM CELL TRANSPLANT.
S. Vagge1 , M. Zeverino2 , S. Agostinelli2 , S. Barra1 , F. Frassoni3 , G.
Taccini2 , A. Bacigalupo3 , R. Corvò1N ATIONAL I NSTITUTE FOR C ANCER R ESEARCH, Department of Radiation
Oncology, Genova, Italy
2
N ATIONAL I NSTITUTE FOR C ANCER R ESEARCH, Medical Physics, Genova,
Italy
3
A ZIENDA OSPEDALIERA UNIVERSITARIA S AN M ARTINO, Hematology,
Genova, Italy
1

Purpose: To report our clinical experience in planning and delivering Total Marrow Irradiation (TMI) after Total Body Irradiation (TBI) in patients withacute leukemia in relapse status or in second remission undergoing an allogeneic stem cell transplant (SCT).
Materials: Patients received conventional TBI as 200 cGy BID/ day for 3
days boosted the next day by TMI (2 Gy in a single fraction) and followed bycyclophosphamide (Cy) 60 mg/ kg for 2 days. While TBI was delivered withlinear accelerator, TMI was performed with helical tomotherapy (HT).
Results: Seventeen patients were treated from July 2009 till August 2010,
eleven with acute myeloid leukemia, five with acute lymphoid leukemia andone with myelodisplasia.. At the time of radiotherapy eight patients were in
relapse, eight in second remission and one in third complete remission (CR)after relapse. The donor was a matched sibling in 7 cases, an unrelateddonor in11 cases. Median organ-at-risk dose reduction with TMI ranged from
30% to 65% with the largest reduction (-50%-65%) achieved for brain, larynx, liver, lungs and kidneys. Target areas (bone marrow sites and spleen in
selected cases) were irradiated with an optimal conformity and an excellent
homogeneity. Follow-up ranges from 90 days to 530 days (median 320 days).
However, tolerance was not different from a conventional TBI-Cy. All patientstreated with TBI/TMI reached CR after SCT. Seven (41%) patients relapsed atmedian time of 276 days (range: 166- 446 days) . Eight (47%) patients have
died, 5 for treatment-related toxicity and 3 for disease relapse. Nine (53%)
patients are alive with five survivors in table clinical remission of disease
Conclusions: This study confirms the clinical feasibility of using HT to deliver
TMI as selective dose boost modality after TBI. Since the rate of relapse
remains high after 14 Gy TBI/TMI, a dose escalation trial to determine themaximum tolerated dose of TMI given as multi-step boost irradiation is now
starting at our institution for the treatment of patients with relapsed acuteleukemia after previous SCT.

Normal tissue

Bandera1 , L. Triggiani1 , L. Donadoni1 , B. Shehi1 , S. Magrini1
1
S PEDALI C IVILI DI B RESCIA, Department of Radiation Oncology, Brescia,
Italy
Purpose: The incidence of PCNSL has increased in the last decades, inimmuno-compromised as well as in immuno-competent individuals; generally
HIV positive patients have a worse prognosis. Nowadays, in a curative setting, the standard treatment of PCNSL is considered systemic chemotherapy
with high dose methotrexate (HD-MTX) and Ara-C, with RT given upfront tocomplete first line treatment. RT can also be considered a less aggressive
possibility in the salvage and/or palliative setting. The aim of this study isto retrospectively analyse the clinical and therapeutic features of 64 patientsconsecutively treated at the Radiation Oncology Department Brescia University between January 1988 and April 2008.
Materials: All the clinical, diagnostic and therapeutic features of the 64 cases
were collected from the clinical records and analysed after their introduction
in a general database. The different clinical and therapeutic features wereanalysed. Overall survival (OS) was calculated from the end of RT to the last
follow-up. "Short" and "long" survivors were defined patients died within 1
and after 6 months from the end of RT, respectively. All statistical analysis
were performed with SPSS 17th software.
Results: In this series two peaks of accrual were observed: 1993 through1997 and in the last two years (2006-2008). Most of the patients were
immunocompetent (83%). Eleven patients had AIDS. Thirty-eight patients(59%) were aged > 60 years, 28 (44%) had IK <=70 and most of them had
different neurological symptoms (95%). The symptoms were often differently
combined but the most frequent were cognitive focal deficits in 43% (28 pts),
depressed level of consciousness 20 % (13 pts); intracranial hypertension
15% (10 pts). The majority of these pts (61%) had histological confirmationof the diagnosis, the others only an unequivocal radiological diagnosis; 35 patients (54%) had high grade lymphoma. The first site of disease was mainlyin the deep structures of the brain (64%). All the patients were treated with
RT and 70% with RT alone. RT dose < 30 Gy was used mostly in young (< 60years), HIV positives and KPS < 70 patients. "Palliative high dose approach"(≥ 30 Gy), older age, KPS ≥ 70, immunecompetency are significantly related with better OS at univariate analysis. Of these factors, RT dose does

S 349

910 poster
ASSOCIATION BETWEEN SINGLE NUCLEOTIDE POLYMORPHISMS
AND HAPLOTYPES IN THE VEGF GENE AND LATE TOXICITY IN
PROSTATE CANCER PATIENTS
T. Langsenlehner1 , E. M. Thurner1 , W. Renner1 , G. Hofmann1 , K. Kapp1 ,U. Langsenlehner1
M EDICAL U NIVERSITY OF G RAZ, Graz, Austria

1

Fig. 1. The distribution of the mean dose to the whole heart and the four heart
valves for our 10 patients for INRT (red) and MF (blue). The boxes represent
25-75% percentile and the whiskers represent the range.
Conclusions: Our results show, that the mean dose to the heart and four
heart valves was much lower with INRT compared with MF for most patients.
However, for a subset of patients, even INRT plans will expose the heart andheart valves to high doses with a 25 year EAR of a cardiac event of up to
3.5%. For such patients the use of even more conformal techniques than
INRT, and/or further dose reduction, is needed to minimize the risk of severe long-term complications. References[1] G. Schellong et al. Late valvular and other cardiac diseases after different doses of mediastinal radiotherapy for Hodgkin disease in children and adolescents. Pediatr Blood Cancer
2010;55:1145-1152.

Purpose: Vascular endothelial growth factor (VEGF) plays a key role in theregulation of angiogenesis and vascular permeability and has been shown
to be up-regulated during the late phase of radiation injury. The present
prospective study was performed to evaluate the association of VEGF single nucleotide polymorphisms (SNPs) and haplotypes with the developmentof radiation induced late side effects in prostate cancer patients.
Materials: To analyze the role of VEGF polymorphisms and haplotypes forhigh-grade rectal or genitourinary late toxicity (defined as late toxicity RTOG
≥2) 493 prostate cancer patients from the Austrian PROCAGENE study
treated with definitive radiotherapy were included in the present investigation. Seven candidate polymorphisms in the VEGF gene were selected anddetermined by 5-nuclease (TaqMan) assays. Haplotypes and linkage disequilibrium were determined using the Haploview program. Haplotype analysis showed two separate blocks of high-linkage disequilibrium, formed by
five polymorphisms (-2578C>A, -2489C>T, -1498C>T, -634G>C, -7C>T) upstream of the coding sequence (promoter and 50-untranslated region) andtwo polymorphisms (936C>T and 1612G>A) downstream of the coding sequence.
Results: Within a median follow-up time of 35 months, 42 patients (8.5%)
developed high-grade late rectal toxicity and 47 patients (9.5%) late bladdertoxicity. In a KaplanMeier analysis, carriers of the VEGF -7C>T polymorphism were at increased risk of high-grade late rectal toxicity (p= 0.003), in
multivariate analysis including clinical and dosimetric parameters as potential
confounders the VEGF -7C>T polymorphism remained a significant predictor for high-grade late toxicity (HR= 2.8, 95% CI 1.349 to 5.813; p= 0.006).

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Furthermore, the ATTGT haplotype demonstrated a significant association
with the risk of late rectal toxicity (p=0.001). No significant associations were
found for the remaining polymorphisms and haplotypes.
Conclusions: We conclude that genetic variants in the VEGF gene may influence the risk of high-grade late rectal toxicity after definitive radiotherapy
in prostate cancer patients.
911 poster
BIOMARKERS OF RADIATION FIBROSIS IN BREAST CANCER: A
METHODS VALIDATION STUDY FOR INTERLEUKIN 6
C. Westbury1 , S. Davies2 , J. Haviland3 , L. Gothard2 , R. Stratton4 , S.
Short1 , J. R. Yarnold2
1
C ANCER I NSTITUTE , UCL, Department of Oncology, London, United
Kingdom
2
I NSTITUTE OF C ANCER R ESEARCH, Academic Radiotherapy, Sutton,
United Kingdom
3
I NSTITUTE OF C ANCER R ESEARCH, Clinical Trials and Statistics Unit,
Sutton, United Kingdom
4
R OYAL F REE AND UCL M EDICAL S CHOOL, Centre for Rhematology andConnective Tissue Disease, London, United Kingdom
Purpose: Biomarkers of fibrotic disease can provide an estimate of fibrotic
activity but have not been determined for established radiation fibrosis. Patients entered into the START trial of breast radiotherapy, in whom normal
tissue outcome data are available, provide a population for investigation ofnovel biomarkers of radiation fibrosis. The study objective was to obtain pilot
data to validate the methods of sample handling and analysis for the candidate cytokine, Interleukin 6 (IL-6), in this population.
Materials: Two cytokines, IL-6 and connective tissue growth factor (CTGF),
implicated in the pathogenesis of fibrosis, were selected from gene expression microarray data comparing paired stromal specimens of irradiated andnon-treated breast tissue from women treated with breast radiotherapy. In thecurrent study, blood and urine were collected from START trial patients withestablished breast fibrosis and control patients with minimal/no breast fibrosis. Plasma, serum and urine samples were processed using standard protocols. Measurements of IL-6 in plasma, serum and urine in patients representing both fibrosis and control groups were carried out using an enzyme-linked
immunosorbent assay (ELISA) from R&D. A reference interval for plasma andserum IL-6 was determined.
Results: Samples have been collected from 22 patients out of a target of
70 patients. All samples were processed and frozen within 3 hours of collection. IL-6 levels in plasma, serum and urine from 10 patients (2 fibrosis
and 8 control) were measured by ELISA. The manufacturer’s specified minimal detectable dose (MDD) for IL-6 was 0.016 pg/ml and one plasma sample
was below this limit (0.00 pg/ml). Median plasma and serum IL-6 levels were0.16 pg/ml (range 0.00-1.22) and 0.38 pg/ml (range 0.08-1.07), respectively.
There was a significant correlation between serum and plasma IL-6 (Spearman rho=0.697, p=0.025). For urine, 6 out of 10 samples assayed were above
the MDD. Of these, the median was 1.52 pg/ml (range 0.08-9.77). For serumand plasma, the results are in keeping with published data for IL-6 levels. For
urine, the IL-6 range is wider in keeping with the fact that protein compositionin urine may differ from serum or plasma.
Conclusions: This pilot data validates planned methods for sample handlingand analysis of the cytokine IL-6 within a population of breast cancer patientstreated with radiotherapy. The normal ranges for IL-6 in serum and plasma
are in accordance with the normal range reported by others using the same
ELISA. In this study, there was no difference between the normal range of IL-6
in serum and plasma. Further data are required to determine the usefulnessof urine as a source of protein for estimation of IL-6 in this patient population.
Future work to compare levels of IL-6 and CTGF in START Trial patients withbreast fibrosis compared to control patients will be carried out to determine
the potential of these cytokines as biomarkers of radiation fibrosis.

rouracil 300 mg/m2 continuously. Patient characteristics: 72 year old malein performance status 1. Former heavy smoker, quitted 22 year prior to treatment. The lung function was normal with FEV1=3.58 l (113%) and FVC=4.44
l (107%). Normal tissue constrains were kept with lung V20=22.3% and meanlung dose=11 Gy. Cone-beam scans (CBCT) were taken at fraction 1, 2, 3,
and 20. Retrospectively the CBCT were deformable registered to planning
CT. By subtracting the first CBCT scan from the other scans the local change
in density of the healthy lung tissue during the treatment course was estimated.
Results: After the RT was completed, the pt experienced increasingly cough,severe dyspnoea, and declining general condition. Pulmonary embolism was
excluded when ventilation-perfusion scintigraphy and CT-scan were executed.
Chest x-ray had diffuse density changes similar to radiation field. The conclusion was RP and treatment with prednisolone and antibiotics were initiated with improvement in consequence. However, it took about 2 months
before the pt was able to return to his usual work. Lung function test in
June: FEV1=3.27 l and FVC=4.29 l.Significant density changes in the healthylung tissue inside the radiation field were observed after 20th fraction. Thesechanges were in the same area as seen on chest x-ray taken 3 weeks afterRT.
Conclusions: This case story about RP indicates that RP might be correlated
to density changes observed on CBCT. Actually the first density changes
were detected after only 10 fractions. If these findings can be established
to a large population this assay could potentially form the basis for adapting
the therapy plan during the treatment course and can be used to identify pts
in great risk of developing RP and initiate early treatment.

therefore modulate responses to radiation and the risk of radiation-induced
late side effects. We selected three functional SNPs in XRCC1 (rs1799782:
Arg194Trp; rs25489: Arg280His; rs25487: Arg399Gln) to analyze their association with radiation-induced late side effects grade ≥2 in patients treatedwith 3DCRT for prostate cancer.
Materials: The present study was performed using 603 participants from the
PROCAGENE study with histological diagnosed prostate cancers who weretreated with three-dimensional conformal radiotherapy in a three-field technique. Late genitourinary and rectal toxicity was graded according to standard RTOG criteria. Genotypes were determined by a 5exonuclease assay(TaqMan). Statistic analysis was done using SPSS 16.0 for Windows.
Results: After a median follow-up time of 35 months, 91 patients experienced
severe genitourinary and/or rectal late side effects, classified as RTOG≥2.
In a KaplanMeier analysis evaluated by log rank test, carriers of a XRCC1
280His allele were at decreased risk of late side effects grade ≥2 (p=0.022).
Univariate Cox proportional hazard analyses showed a lower risk of late side
effects grade ≥2 for carriers of an XRCC1 280His allele (HR=0.28, 95% CI
0.09 - 0.90; p = 0.032). In a multivariate Cox regression model including clinical and dosimetric factors as potential confounders the XRCC1 Arg280His
polymorphism remained a significant factor predicting for lower risk of highgrade late toxicity (HR= 0.229, 95% CI 0.054 to 0.976; p= 0.046). None of
the remaining polymorphisms was significantly associated with late toxicity
grade≥2.
Conclusions: The Arg280His polymorphism in the XRCC1 gene may be protective against the development of severe late side effects after radiotherapy
for prostate cancer.
914 poster
LATE RECTAL TOXICITY FOLLOWING IRRADIATION IN RATS
H. Doi1 , N. Kamikonya1 , Y. Takada1 , M. Fujiwara1 , K. Tsuboi1 , H. Miura1 ,H. Inoue1 , M. Tanooka1 , T. Nakamura2 , T. Shikata2 , T. Tsujimura3 , S.
Hirota1
1
H YOGO C OLLEGE OF M EDICINE, Department of Radiology, Nishinomiya,Japan
2
T HE H OSPITAL OF H YOGO C OLLEGE OF M EDICINE, Department ofPharmacy, Nishinomiya, Japan
3
H YOGO C OLLEGE OF M EDICINE, Department of Pathology, Nishinomiya,Japan

912 poster
CAN RADIATION PNEUMONITIS BE DETECTED EARLY BY CBCT IN
THORACIC CANCER PATIENTS TREATED WITH RADIOTHERAPY?
T. Schytte1 , A. Bertelsen2 , C. Brink2 , O. Hansen1
1
O DENSE U NIVERSITY H OSPITAL, Departments of Radiation Oncology andCell Biology, Odense, Denmark
2
O DENSE U NIVERSITY H OSPITAL, Department of Medical Physics andRadiation Safety, Odense, Denmark
Purpose: BackgroundRadiation pneumonitis (RP) is one of the most common and serious treatment-related toxicity to definitive radiotherapy (RT) in
thoracic cancer patients (pts). The mildest cases are detected radiographically, whereas clinically evident RP may involve cough, dyspnoea, fever. In
severe cases RP is potentially lethal. The question is whether signs of RP
are evident early in the treatment course.
Materials: This is a case story of a pt with oesophageal cancer who wastreated with definitive chemo-radiotherapy in February-Marts 2009. The radiotherapy was 3D-CT planned IMRT 60 Gy/ 30 F with concomitant fluo-

S 351

913 poster
CORRELATION BETWEEN SINGLE NUCLEOTIDE POLYMORPHISMS IN THE XRCC1 GENE AND THE RISK OF SEVERE SIDE
EFFECTS AFTER RADIOTHERAPY FOR PROSTATE CANCER
E. M. Thurner1 , W. Renner1 , U. Langsenlehner1 , A. Gerger1 , G. Hofmann1 ,K. Kapp1 , T. Langsenlehner1
1
M EDICAL U NIVERSITY OF G RAZ, Graz, Austria
Purpose: XRCC1 is a major player in the base excision repair pathway andis involved in the repair of DNA single-strand breaks. We hypothesized thatpolymorphisms in gene for XRCC1 would influence DNA repair capacity andPurpose: The purpose of this study was to establish the experimental rat
model of late radiation proctitis, and to examine the assessment strategy.
Materials: A total of 57 female Wistar rats (5 weeks old) were used in thepresent study. 45 of them were divided into four groups due to the follow-up
term after irradiation as follows; Group A ; those sacrificed at the 4th week
following irradiation(n=12), Group B; those sacrificed at the 12th week following irradiation (n=11), Group C; those sacrificed at the 24th week following
irradiation (n=11), Group D; those sacrificed at the 37th week following irradiation (n=11). These rats were irradiated. The remaining 12 rats were thecontrol group without irradiation. The rats, which belonged to Group A to D,
were irradiated to the rectum selectively with a single fraction of 25 Gy underanesthesia. The clinical findings were observed sequentially following irradiation. Rats in each group were sacrificed according to the experimental
plan. The rectum was removed immediately following sacrifice, and evaluated macroscopically and pathologically. The results in the macroscopic findings were graded from 0 to 4 and compared among the groups according tomilder or more severe status as applicable. The absolute number of vessels
was counted in four specimens individually in microscopy. In addition, thediameters of the lumen and the vascular endothelium were measured in the
stenosed vessels, and the former was divided by the latter to evaluate the degree of the vascular stenosis. In addition, the results in the degree of vascularstenosis were graded from 0 to 4. The relationship between the groups wasassessed using a chi-squared test and Fisher’s exact test (P<0.05).
Results: The clinical findings occurred apparently on the 10th day, decreased
at the 4th week once, and developed again. Five irradiated rats died in thefollow-up term, and these rats were excluded from the histological evaluation.
The results in the macroscopic findings in Group B were significantly milder
than the other groups. In the pathological examination, squamous metaplasia
and submucosal fibrosis were found in the rectal mucosa in Group A. Vascular stenosis was found with fibrinoid necrosis and thickening of the wall. In
Group B, C, and D, the regeneration of the damaged epithelium proceededwith time. However, the glandular epithelium was displaced into the submucosa, and the heteromorphic structure of the epithelium was found. The
absolute number of vessels per individual was 289.7 (±63.5), 385.8 (±60.6),
256.6 (±70.0), 282.1 (±57.1), 141.4 (±47.5) in Group A, B, C, D, and thecontrol group respectively. In addition, significant differences were observed
between Group B and the other groups, and also between the control groupand the irradiated rats of the other groups. The degree of stenosis could
be evaluated in microvessels microscopically. The proportions of stenosed
vessels in Group A, B, C, and D accounted for 16.0%, 10.6%, 13.3%, and14.6% respectively in a total of the absolute number of vessels. In addition,
no significant differences were observed between GroupA and D, and also
between Group C and D. In the proportion of the severe stenosis, there wereno significant differences among the groups.
Conclusions: The sequential changes following irradiation were observed inS 352

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the rectal mucosa in the present study. The results indicated late radiation
proctitis followed acute proctitis. We could establish an animal experimental
model of late radiation proctitis, and also established a novel method to evaluate the severity of late radiation proctitis focusing microangiopathy. Our animal experimental model may be also used as an animal experimental modelof radiation induced microangiopathy.
915 poster
MORBIDITY PROFILES FOLLOWING CONFORMAL VS. INTENSITYMODULATED RADIOTHERAPY FOR URINARY BLADDER CANCER.
J. Søndergaard1 , M. Holmberg2 , A. R. Jakobsen3 , L. P. Muren4 , C. Grau1 ,irradiated individually with a single dose of 8 Gy. 2, 2, 4 and 1 deaths were
occurred in groups, respectively. Animals underwent both Tc99m DTPA (Diethylene triamine pentaacetic acid) dynamic renal imaging and Tc99m DMSA
(Dimercaptosuccinic acid) static renal imaging at the end of three months
follow-up period. Proximal tubular degeneration, tubular atrophy, interstitial
fibrosis and glomerular degeneration were assessesed histopathologically.
Results: The mean Tmax and T1/2 values in the RT group were 4.2 ± 0.8
and 14.5 ± 4.1, respectively. In the L-Carnitine + RT group, those values
were 2.8 ± 0.4 and 12.8 ± 1.7 and significantly lower than those in the RT
group (p=0.03, p=0.04). In L-Carnitine + RT group, the glomerular structures
were well protected compared to RT group (0.78 ± 0.22 vs. 1.88 ± 0.58,
p=0.04) (Table 1).

M. Hoyer1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
A ALBORG U NIVERSITY H OSPITAL, Department of Oncology, Aalborg,
Denmark
3
A ALBORG U NIVERSITY H OSPITAL, Department of Medical Physics,
Aalborg, Denmark
4
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
1

Purpose: The improved dose distributions of intensity modulated radiotherapy (IMRT) compared to conformal radiotherapy (CRT) is well characterized
in radiotherapy (RT) of pelvic tumours. Moreover, previous studies in particular for prostate cancer have reported a reduction of toxicity enabling treatment
intensification and improved outcome. In RT of bladder cancer large intestinal
volumes are irradiated in particular when pelvic lymph nodes are included in
the target. The purpose of the present study was to evaluate acute and late
toxicity following RT for bladder cancer and to correlate these to dose-volume
parameters. This analysis was performed in patients treated in the same time
period at two different RT centres where patients according to local policy received IMRT in one centre and CRT in the other.
Materials: 116 consecutively treated patients with muscle invasive bladdercancer who received either CRT (n=66) or IMRT (n=50) in the time period
2007-2010 were analysed. Patient charts and treatment plans were retrospectively evaluated. A cross-sectional evaluation of late toxicity was performed by telephone interview of 44 surviving and recurrence free patients.
Acute and late toxicity was scored according to the Common Terminology
Criteria for Adverse Event version 3.0 (CTCAE). The toxicity scores were dichotomized, and comparisons between the groups were analyzed by twosided Fishers exact test and logistic regression modelling where appropriate.
Results: Acute diarrhoea grade 2+ occurred more frequently in patientstreated by CRT (56%) compared to IMRT (30%) (p=0.008). There were nodifferences in other acute gastrointestinal (GI) toxicities such as bowel painor the use of anti-diarrhoea medication. The acute genitourinary (GU) toxicities were not different in the two groups receiving IMRT or CRT. Logistic regression analysis revealed a statistically significant correlation between acutediarrhoea and volume of bowel cavity exposed to irradiation. Severe late toxicity (CTCAE grade 3+) was recorded in 10% in the total patient cohort; there
was no difference between the IMRT and CRT groups. In the cross-sectional
study any late grade 2+ GI toxicity occurred in 17% and 40% of patients receiving IMRT and CRT, respectively (p=0.1), while the corresponding no. forany late grade 2+ GU toxicity were 63% and 48% of the patients (p=0.4).
Conclusions: Patients treated with IMRT experienced significantly less acutediarrhoea compared to those treated with CRT, whereas there was no significant difference in late morbidity. The increased occurrence of acute diarrhoea
in CRT patients could be explained by the high bowel volume receiving irradiation by this treatment.
916 poster
PROTECTIVE ROLE OF CARNITINE AGAINST RADIATIONINDUCED KIDNEY DAMAGE IN INFANT RATS: SCINTIGRAPHIC
AND HISTOPATHOLOGIC EVALUATION
C. Rusen1 , G. Durmus Altun2 , F. Oz Puyan3 , M. Saynak1 , K. Ibis1 , A.
Özen1 , G. Bayir-Angin1 , F. Ustun4 , B. Denizli1 , S. Parlar1 , M. Caloglu1 , V.
Yurut-Caloglu1 , M. C. Uzal1 , Z. Koçak1
1
T RAKYA U NIVERSITY M EDICAL FACULTY, Radiation Oncology, Edirne,
Turkey2
T RAKYA U NIVERSITY M EDICAL FACULTY, Nuclear Medicine, Edirne, Turkey
3
T RAKYA U NIVERSITY M EDICAL FACULTY, Pathology, Edirne, Turkey
4
C ANAKKALE U NIVERSITY FACULTY OF M EDICINE, Nuclear Medicine,
Canakkale, Turkey
Purpose: The aim of this paper is to clarify, whether L-carnitine has a protective effect in prevention of radiation induced nefrotoxicity (RIN) during latephase following radiation therapy in an infant rat model.
Materials: Thirty-one two-week-old male Wistar albino rats divided into fourgroups. Group 1 (n=10): Control, Group 2 (n=10): L-Carnitine alone, Group 3(n=10): Irradiation alone (RT), Group 4 (n=10): L-Carnitine before irradiation(L-Carnitine + RT), injected with L-Carnitine (LC) (300 mg/kg) i.p., 30 minutes
before the irradiation. The rats in the RT and L-Carnitine + RT groups wereConclusions: The use of radioprotective drug is more important for children where there is probability of long-term survival. L-Carnitine is a natural
substance, which is well tolerated and can be given by oral administration.
L-Carnitine may have protective effects on RT-induced late nephrotoxicity ininfantile period.
917 poster
RADIATION-INDUCED CHRONIC-OXIDATIVE RENAL DAMAGE CAN
BE REDUCED BY AMIFOSTINE
C. Rusen1 , V. Yurut-Caloglu1 , S. Eskiocak2 , A. Özen1 , K. Ibis1 , N. Turan3 ,B. Denizli1 , M. C. Uzal1 , M. Kaldir4 , M. Saynak1 , S. Parlar1 , M. Caloglu1 , B.
Uregen1 , Z. Koçak1
1
T RAKYA U NIVERSITY M EDICAL FACULTY, Radiation Oncology, Edirne,
Turkey2
T RAKYA U NIVERSITY M EDICAL FACULTY, Biochemistry, Edirne, Turkey
3
T RAKYA U NIVERSITY M EDICAL FACULTY, Biostatistics, Edirne, Turkey
4
EBV SAĞLIK ÜRÜNLER İ SAN.VE T İC.LTD ŞT İ, Radiation Oncology,
Istanbul, Turkey
Purpose: In the current study, amifostine is evaluated for its radioprotective role in serum and kidney tissue by oxidative (malondialdehyde-MDA, advanced oxidation protein product-AOPP) and antioxidative markers (catalase,
glutathione-GSH, free-thiols-F-SH).
Materials: Thirty Wistar-Albino 3-4 months old, female rats, were randomly
divided into Group I (n=10): Control, Group II (n=10): Irradiation-alone, GroupIII (n=10): Amifostine before irradiation. In group II and III, right kidneys of therats were irradiated with a single dose of 6 Gy using a Co60 treatment unit.
Rats in group III received 200 mg/kg amifostine intraperitoneally, 30 minutes
prior to irradiation. Following sacrification at 24th week, blood and kidney
tissue samples were collected. Statistical analysis was done by One way
ANOVA, Post-hoc Bonferroni, Dunnett T3 and Mann-Whitney U tests.
Results: Administration of amifostine significantly decreased the serum
AOPP and MDA levels when compared to the irradiation-only group (p=0.004,
p=0.006; respectively). Also amifostine significantly increased serum catalase activities and GSH levels, when given 30 min prior to irradiation (p=0.02,
p=0.000; respectively). In the kidney tissue, administration of amifostinesignificantly decreased AOPP and MDA levels (p=0.002, p=0.016; respectively). Tissue GSH activity was increased following amifostine administration(p=0.001) (Table 1).
Conclusions: Amifostine may reduce radiation-induced nephropathy by inhibiting chronic oxidative stress. Biomarkers of oxidative stress in serum andkidney tissue may be used for evaluation of the radiation-induced nephropathy.

perfusion chemotherapy (LPC) for T3-pancreatic cancer and the result indicated the increase of the long-term survival. Specific aim of this analysis wasto assess long-term renal function after preoperative CRT.
Materials: Preoperative CRT consisted of concurrent radiotherapy (50 Gy in
25 fractions) and chemotherapy (GEM 1,000 mg/m2 intravenous, weekly for
12-15 weeks, three times during 4 weeks). Irradiation fields covered boththe primary pancreatic tumor and retropancreatic tissues including the aorta,celiac, and superior mesenteric arteries. Between 2002/6 and 2007/9, we
treated 123 patients with 50 Gy of radiotherapy except for 2 patients whose
treatment was stopped at 46 and 48 Gy. Patients underwent restaging andwere taken to surgery in the absence of disease progression. Surgical resection was performed to 82 (67%) of 123 patients. The renal function ofpatients survived for >3 years after CRT was assessed by the changes of theestimated glomerular filtration rate (eGFR), prior to CRT and 1-, 2-, 3-years
after CRT.
Results: Forty (33%) of 123 patients survived for > 3 years after CRT andno patients who survived <3 years after CRT died of radiation-associatedrenal dysfunction. The characteristics of these 40 patients who survived
for >3 years were as follows; median age was 65 years (range, 41-81),
20 (50%) were female, median planning target volume (PTV) of radiotherapy was 223 cm3 (range, 111-380), and percentage of bilateral renal
volume receiving at least 5/10/15/20/25/30/35 Gy and mean kidney dosewere 71/48/39/25/11/5/2% and 13 Gy, respectively. With median followup of 50 months (range, 38-88), mean eGFR slightly decreased from 80.7
mL/min/1.73 m2 (range, 57.3-103.3, SD 11.2) before CRT to 81.6, 78.2, 76.5
mL/min/1.73 m2 at 1-, 2-, 3-years after CRT, respectively.
Conclusions: Preoperative CRT with relatively small PTV for T3-pancreaticcancer did not affect the renal function at 3 years follow-up.
919 poster
THE PROTECTIVE EFFECT OF AMIFOSTINE ON RADIATIONINDUCED PROCTITIS: SYSTEMIC VERSUS TOPICAL APPLICATION
M. C. Uzal1 , A. Sezer2 , U. Usta3 , N. Sut4 , A. Özen1 , M. A. Yagci2
1
T RAKYA U NIVERSITY M EDICAL FACULTY, Radiation Oncology, Edirne,
Turkey2
T RAKYA U NIVERSITY M EDICAL FACULTY, General Surgery, Edirne, Turkey
3
T RAKYA U NIVERSITY M EDICAL FACULTY, Pathology, Edirne, Turkey
4
T RAKYA U NIVERSITY M EDICAL FACULTY, Biostatistics, Edirne, Turkey
Purpose: The aim of the study was to evaluate the radioprotective efficacy of
intrarectal administration of amifostine in radiation-induced proctitis compared
to intraperitoneal administration.
Materials: 32 Sprague-Dawley rats were randomly divided into four groups:
Control (CONT), irradiation alone (RT), intraperitoneal amifostine plus irradiation (IPAMI), and intrarectal amifostine plus irradiation (IRAMI). The rats in the
RT, IPAMI and IRAMI groups were irradiated individually with a single dose of
17.5 Gy to the pelvis.Amifostine was administered by the intraperitoneal (200mg/kg) or intrarectal (2000 mg/kg) method before irradiation. Histopathologic
analysis of rectum was performed 14 days after irradiation.
Results: Significant radiation damage appeared in all histopathologic parameters and was reduced by amifostine.Pretreatment with IPAMI significantly
reduced the inflammatory infiltrate in the lamina propria (p=0.021), cryptitis (p=0.002), crypt abscess (p=0.015). However, the protective effect of
IRAMI was significant for all parameters with equal or higher significance than
IPAMI, including the eosinophil leucocytes count (p=0.02), distortion of thecrypts (p=0.008), and was also significant for regenerative/reparative atipia(p=0.013) (Table 1).

918 poster
RENAL FUNCTION AFTER PREOPERATIVE CHEMORADIATIONFOR T3-PANCREATIC CANCER
S. NAKAMURA1 , Y. Kawaguchi1 , O. Suzuki1 , K. Nishiyama1
1
O SAKA M EDICAL C ENTER FOR C ANCER AND C ARDIOVASCULAR D IS EASES , Radiation Oncology, Osaka, Japan
Purpose: We performed a combination of preoperative concurrent chemoradiotherapy (CRT) with full-dose gemcitabine (GEM) and postoperative liver

Conclusions: Intrarectal high dose topical administration of amifostine ismore effective in the prevention of radiation-induced proctitis when comparedwith its intraperitoneal systemic administration.

S 353

920 poster
WHY THERE ARE NO EVIDENT THRESHOLD DOSE-VOLUME
PARAMETERS FOR THE LUNG?: THE IMPACT OF CLINICALFACTORS AND CHEMOTHERAPY ON PULMONARY FUNCTION
TESTS
B. Sanchez-Nieto1 , K. Goset Poblete2 , I. Caviedes Soto34 , I. Delgado
Becerra5 , A. Córdova Bernhardt2
1
P ONTIFICIA U NIVERSIDAD C ATÓLICA DE C HILE, Facultad de Física,
Santiago, Chile
2
C LINICA A LEMANA DE S ANTIAGO, Unidad de Radioterapia, Santiago, Chile
3
C LINICA A LEMANA DE S ANTIAGO, Servicio Broncopulmonar, Santiago,
Chile
4
FACULTAD DE M EDICINA , C LÍNICA A LEMANA -U NIVERSIDAD DEL D ESAR ROLLO , Departamento de Medicina, Santiago, Chile
5
FACULTAD DE M EDICINA , C LÍNICA A LEMANA -U NIVERSIDAD DEL D ESAR ROLLO , Instituto de Epidemiología y Políticas de Salud Pública, Santiago,
Chile
Purpose: The QUANTEC publication (1) addresses the need for knowledgeof how dose distributions affect normal tissue (NT) outcomes. This publication
includes 16 organ specific clinical papers. Regarding the lung (2), an extensive literature review was carried out. One of the conclusions is that there areno evident threshold "tolerance dose-volume" levels and that a further understanding of the impact of clinical factors (among others) is required (2).The
purpose of this work addresses the above open question by proposing multivariate (dose-volume parameters, clinical factors and systemic agents) predictive models for changes in pulmonary function tests (∆PFTs) of breast
cancer and lymphoma patients undergoing radiotherapy (RT).
Materials: A prospective study was designed to measure ∆PFTs in patients
undergoing RT. 66 patients were included. Unambiguous endpoints (Spirometry, Lung Capacities and Diffusing Capacity for carbon monoxide) and NT
organ definition (irradiated lung) were used. Multivariate analysis including
single and interaction terms were carried out.
Results: Predicting ∆PFTs based solely on dosimetric factors is not ideal. Ina univariate analysis, threshold levels impact on ∆PFTs exhibited a dependence on the latency of the damage. In the multivariate analysis most of thesingle factors did not retain significance; only interaction terms did so.
Conclusions: Multifactorial modeling based on tolerance dose-volume, clinical factors (e.g, pre-RT functional status and smoking habits) and chemotherapy regimes are proposed separately for each ∆PFT, being different for acuteand late changes.
References
1. Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC):
Int. J. Radiation Oncology Biol. Phys., Vol. 76, No. 3, 2010.
2. Marks et al. Radiation dose-volume effects in the lung. Int. J. Radiation
Oncology Biol. Phys., Vol. 76, No. 3, (pp S70-S76), 2010.

S 354OTHERS

OTHERS

Others921 poster
SBRT DOSE ESCALATION PHASE I STUDY FOR LIVER METASTASES USING VOLUMETRIC MODULATED ARC THERAPY
S. Castiglioni1 , A. Tozzi1 , P. Mancosu1 , P. Navarria1 , S. Pentimalli1 , F.

cleation. Symptom control included eight TTT for exudative retinal detachment and ten cataract surgeries. At most recent followup, 32 patients (71%)
maintained 20/200 vision or better in the treated eye. In this first report of131
Cs plaque therapy with a mean followup of 20 months, there were two TTT
procedures and one definitive failure requiring enucleation after ten months.
Published results from 22 series were reviewed and reported.

Alongi1 , E. Clerici1 , A. Fogliata2 , L. Cozzi2 , G. Torzilli3 , M. Scorsetti1
1
I STITUTO C LINICO H UMANITAS, Radiotherapy and radiosurgery department, Rozzano (Milan), Italy
2
O NCOLOGY I NSTITUTE OF S OUTHERN S WITZERLAND, Medical Physics
Unit, Bellinzona, Switzerland
3
I STITUTO C LINICO H UMANITAS, General Surgery, Rozzano (Milan), Italy
Purpose: To report the feasibility and early clinical results of a phase I studyof stereotactic body radiotherapy (SBRT) delivered with modulated volumetricarc therapy (VMAT) for the treatment of patients with liver metastases.
Materials: Patients with one to three hepatic lesions and maximum individual
tumour diameters less than 6cm, that were inoperable or medically unsuitable for resection, were recruited to this research ethics board approved trial.
Chemotherapy was not given from 2 weeks before to 4 weeks after SBRT.
From December 2008 to November 2010, 21 patients were enrolled in thistrial. Patients were immobilized during multi-phases CT simulation with vacuum pillow and personalized body mask using abdominal compression. Daily
cone beam CT was performed before each fraction to minimize the set-up uncertainties. SBRT was delivered with VMAT by RapidArc technique. Initially a
total dose to the isocenter of 50Gy/3 fractions (group A) was prescribed anddelivered, afterwards a dose escalation until 75Gy/3fractions was planned(group B). The organs at risk (OAR) considered were: healthy liver (dose at
700cm3 <15Gy), spinal cord (maximum dose Dmax<21Gy), kidneys (volume
receiving 15Gy V15<35%), stomach and duodenum (Dmax<21Gy), heart(mean dose<30Gy). If it was not possible to respect the dose constraints
for normal tissues, an initial dose reduction of 10% was provided and if necessary further reductions of up to 30%. Local response was defined using
modified RECIST (Response Evaluation Criteria in Solid Tumor) to describe
the change in the irradiated metastases.
Results: Three patients (four lesions) were treated in group A, 18 patientsin group B (3 with reduction of dose to 30%). Overall treatment was welltolerated with no radiation induced liver disease, serious liver toxicity, or otherdose limiting toxicity for both groups A and B. Only one patient in group B had
acute toxicity gr2 (vomiting). Blood tests after radiation treatment didn’t findaltered hepatic function unless an increase of γ GT in 1 and in 5 patients ofgroup A and B, respectively. At median follow-up of 9 months 7 patients hadcomplete remission, 4 partial remission, 5 stable disease, 5 local progression
out of treatment volume.
Conclusions: SBRT using VMAT is feasible, safe and effective for patientswith liver metastases, with minimum toxicities and good local control. Deeper
investigation is required to evaluate the global life expectancy.
922 poster
A 17-YEAR RETROSPECTIVE STUDY OF EYE PLAQUE
BRACHYTHERAPY FOR UVEAL MELANOMA USING 125I,
103PD, AND 131CS
K. Leonard1 , N. Gagne1 , J. Mignano1 , J. Duker2 , E. Bannon1 , M. Rivard1
1
T UFTS M EDICAL C ENTER, Radiation Oncology, Boston, USA
2
T UFTS M EDICAL C ENTER, Department of Ophthalmology, Boston, USA
Purpose: Survival, local and distant failure rates, ocular toxicity, and visionpreservation in patients treated with Collaborative Ocular Melanoma Study(COMS) eye plaque brachytherapy from our institution were compared withthose in the published literature.
Materials: Records were available and reviewed for 53 patients with the diagnosis of uveal melanoma treated with plaque brachytherapy at TMC overthe past 17 years. AJCC staging (T1, T2, or T3) was 4, 39, and 10 patients,
respectively. All patients were treated using 125 I (n = 37), 103 Pd (n = 5), or131
Cs (n = 11) to a dose of 85 Gy (or documented as 100 Gy prior to 1996 forthe same physical dose) prescribed to a height of 5 mm from the tumor basefor tumors < 5 mm in height or to the tumor apex for tumors > 5 mm in height.
All patients were treated to a total physical dose of 85 Gy (documented as
100 Gy prior to November 1996) prescribed to a height of 5 mm from thetumor base for tumors < 5 mm in height or to the tumor apex for tumors > 5
mm in height. Plaques ranged from 14 mm to 22 mm (chosen to accommodate the maximum tumor basal dimension with a 2-3 mm margin), and were
either standardized COMS plaques or notched (about 23% of patients) witha lip for positioning and shielding of the optic nerve. Treatment planning was
performed using the AAPM TG-43 2D formalism for the model 6711 125 I (Oncura, Inc., Princeton, NJ), model 200 103 Pd (Theragenics, Inc., Buford, GA),and model CS-1 Rev2 131 Cs (IsoRay Medical, Inc., Richland, WA) sources.
Results: With a mean followup of 75 months, 38 of 53 patients were still
alive. Five patients (all 125 I) developed liver metastases (9%) with no evidence of local failure. There were ten definitive local failures and four additional transpupillary thermo-therapy (TTT) procedures performed to ensure
local control for lesions slow to respond. Twelve patients (23%) required enu-

ml and 919 ml vs. 914 ml). The similar tendency was observed in low dose
irradiated volume of the body. The mean monitor units to deliver a 2.0-Gy
fraction were significantly larger in cIMRT than RapidArc (873 vs. 354).
Conclusions: RapidArc delivered IMRT for WV with a fewer monitor units
while keeping the target coverage and the normal tissue sparing, comparedwith cIMRT. The median dose to the normal brain and body didn’t significantly
differ between two techniques.

Conclusions: Adjuvant treatment with chemoradiation is a feasible procedure in hospitals in the public health system in Chile with similar results to
those of the international literature. The use of capecitabine decreased overall survival. There is a lack of studies that demonstrate their equivalenceon the standard adjuvant treatment with the standard adjuvant radiotherapy
and 5 fluorouracil in patients with locally advanced gastric adenocarcinoma
completely resected.

924 poster

926 poster

ADIUVANT RADIOCHEMOTHERAPY FOR GASTRIC CANCER PATIENTS - SINGLE-INSTITUTION RETROSPECTIVE EXPERIENCE.
D. Hempel12 , E. Popławska-Maksimowicz1 , P. J. Barbara1 , E. Sierko12 , T.

AN ADAPTIVE THRESHOLD ALGORITHM FOR FDG-PET/CT
TARGET VOLUME DELINEATION: VALIDATION IN LYMPHNODES.
L. Vigna1 , L. Deantonio2 , R. Matheoud1 , G. Sacchetti3 , G. Loi1 , P. Della

Filipowski1 , M. Z. Wojtukiewicz32
C OMPREHENSIVE C ANCER C ENTER, Department of Radiotherapy,
Bialystok, Poland
2
M EDICAL U NIVERSITY, Department of Oncology, Białystok, Poland
3
C OMPREHENSIVE C ANCER C ENTER, Department of Oncology, Bialystok,
PolandMonica1 , S. Valzana1 , L. Leva4 , M. Brambilla4 , M. Krengli5
1
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Medical Physics,
Novara, Italy
2
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Radiation Oncology,
Novara, Italy
3
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Nuclear Medicine,
Novara, Italy
4
U NIVERSITY H OSPITAL M AGGIORE DELLA C ARITÀ, Novara, Italy
5
U NIVERSITY OF P IEMONTE O RIENTALE, Radiation Oncology, Novara, Italy

1

Conclusions: Our disease control and ocular results were comparable
to those in the literature given the extended followup. The findings for131
Cs were comparable to other radionuclides. We are developing a multiinstitutional, prospective clinical protocol for considering radionuclide selection and other prescriptive criteria.
923 poster
A PLANNING COMPARISON OF RAPIDARC AND CONVENTIONAL
MLC INTENSITY-MODULATED RADIOTHERAPY FOR WHOLE
VENTRICLES
K. Sakanaka1 , M. Takashi1 , H. Masahiro1
1
K YOTO U NIVERSITY, G RADUATE S CHOOL OF M EDICINE, Radiation
Oncology and Image-applied Therapy, Kyoto, Japan
Purpose: To investigate whether RapidArc for whole ventricles (WV) canachieve sufficient target coverage and spare the normal brain compared withconventional MLC intensity-modulated radiotherapy (cIMRT).
Materials: Computed tomography datasets of 13 patients with localized intracranial germinoma were included. Clinical target volume (CTV) was defined as the volume of the tumor bed with a 15 mm expansion plus the volumeof the third, fourth and lateral ventricles with a 5 mm expansion. Planning target volume (PTV) was created with a 5 mm margin to the CTV. Volumes of
the normal brain (brain minus PTV) and body were also contoured. Plansof cIMRT and RapidArc were created on the Eclipse treatment planning system using 6 MV X-rays with 5 mm wide multileaf collimator. 24 Gray wasprescribed to the PTV in 12 fractions. Seven coplanar fixed gantry beams
were used in cIMRT and double arc beams in RapidArc. In optimization forboth techniques, the primary objective was to satisfy D98% (DX% represents
the dose covering X% of the structure volume) to the PTV > 98% of the prescribed dose and D2% to the PTV < 107% of the prescribed dose. As far as
satisfying the target constraints, the dose to the normal brain were minimized.
After completing optimization and dose calculations, the value of D50% to
the PTV in plans of RapidArc was normalized to the same value in plans ofcIMRT. For target comparison, D2%, D98% and homogeneity index (HI) =(D2%-D98%)/D50% were used. For the normal brain and body, D50% andthe volume of the normal brain and body receiving 6 Gy, 3 Gy and 1 Gy (V6Gy, V3 Gy and V1 Gy) were compared between 2 techniques. Paired t-test
was used for comparisons and all statistical tests were two sided. A p value< 0.05 was considered as significant.
Results: Mean D50% to the PTV was 102.4% of the prescribed dose inboth plans. D2% and D98% to the PTV and D2% to the normal brain weresignificantly smaller in cIMRT than in RapidArc but those differences wereless than 1% of the prescribed dose (98.2% vs. 98.7%, 104.8% vs. 105.3%
and 100.1% vs. 100.8%). HI and D50% to the normal brain and body didn’t
significantly differ between two techniques. V1 Gy of the normal brain was
smaller in cIMRT than in RapidArc (1028 ml vs. 1044 ml), while V3 Gy andV6 Gy of the normal brain was larger in cIMRT than RapidArc (880 ml vs. 870

S 355

Purpose: Radical surgery is the treatment of choice in gastric cancer patients(pts). Postoperative concurrent radiochemotherapy is indicated for resected
II-IIIB stage pts. The aim of the study was to analyze experience of a single
institution in adiuvant 3-D conformal radiotherapy (CRT) in combination withchemotherapy (CT) for operable gastric cancer pts.
Materials: 3D CRT with 5-fluorouracyl and leucovorin was apllied in 37 gastric cancer pts. In both cases conventional fraction dose of RT was delivered
using megavoltage X-ray energy (6, 9 and 15 MV). The toxicity of the treatment was evaluated on the basis of CTC NCI v 3.
Results: Median age of the pts was 58 yrs (range, 51-65 yrs). The groupconsisted of 29 males and 8 females. Eight pts were diagnosed at II, 14 at
III A and 15 at III B stage of the disease. In 16 pts tumor was situated in the
body of gastric, in 11 in the cardia and in 10 pts in the pylorus of gastric.
The mean radiation total dose was 45.7 Gy (range, 45-54 Gy) with the mean
treatment delivering time of 37 days. Left kidney received the mean dose of
23.3 Gy, the right 10.6 Gy. D30, D50, D60, D100 was 30, 22, 19, 7 Gy for left
kidney and 14, 9, 3, 2 Gy for right, respectively. The treatment toxicity wasobserved as radiation dermatitis: grade (G) 1 6 pts (16%), diarrhea: G1 4
pts (11%) and G2 1 pts (3 %); nausea: G1 7 pts (19%) and G2 2 pts (5.5%);
vomit: G1 2 (5.4%), abdominal pain 3 pts (8 %). No grade 3, 4 or 5 toxicity
was observed. The mean hemoglobin and creatine level prior to RT-CT was
12,3 g/dl and 0,7 mg/dl, after completed treatment 12,0 g/dl and 0,6 mg/dl,
respectively. Median follow-up was 14 months (2 54 months). One-year,
2-year and 3-year overall survival were 85%, 65% and 50%, respectively.
Patients with negative lymph nodes N(-) had higher 1-year, 2-year and 3-year
overall survival than lymph nodes positive gastric cancer pts (100%, 67% and
67% vs 74%, 64% and 45%, respectively).
Conclusions: Adiuvant radiochemotherapy for operable gastric cancer pts
is a feasible therapeutic modality with acceptable toxicity profile. Patientswith negative lymph nodes present better overall survival than those withmetastatic lymph nodes.
925 poster
ADJUVANT RADIOCHEMOTHERAPY IN GASTRIC CANCER COMPLETELY RESECTED: HOSPITAL VAN BUREN EXPERIENCE,
VALPARAISO, CHILE
N. Isa1 , J. Solis2
1
G RUPO IMO, Radiation Oncology, Madrid, Spain
2
H OSPITAL C ARLOS VAN B UREN VALPARAISO, Oncología Radioterápica,
Valparaiso, Chile
Purpose: Retrospective analysis of overall survival and prognostic factors ofsurvival in patients with locally advanced gastric adenocarcinoma, completely
resected treated with adjuvant concurrent radiochemotherapy.
Materials: From December 2007 to December 2009, 80 patients with locallyadvanced gastric adenocarcinoma, completely resected, stages IIA to IIIC
were treated with adjuvant concomitant chemoradiotherapy in the oncology
department of the Van Buren Hospital, Valparaiso, Chile. The median age
was 64 years. The treatment consisted of total or subtotal gastrectomy with
D1 or D2 lymphadenectomy, followed by conformal radiotherapy, 45 Gy in 25
fractions over the tumor bed, regional nodes and anastomosis sites. Concomitant chemotherapy consisted of 5 fluorouracil (425-500 mg/mt2/dia) andleucovorin (20 mg/mt2/dia) during the first and fifth weeks of radiotherapy or
capecitabine (600-650 mg/mt2 / twice a day) Monday to Friday for 25 days
during radiotherapy.
Results: With a median follow up of 25.8 months in living patients, overall
survival at 2 years was 64.3%. In univariate analysis the statistically significant factors of poor prognosis for overall survival were tumor-infiltrating surrounding tissues (T4), have involved nodes, higher AJCC stage and the useof capecitabine. In multivariate analysis the only factor that decreased overall
survival was the use of capecitabine.

Purpose: To validate an adaptive threshold algorithm (ATA) for tumor delineation on FDG-PET image derived from phantom measurement.
Materials: In our institution, 25 patients who underwent a staging FDGPET/CT examination showing 37 distinguishable non-confluent nodal (LN)
FDG accumulation (LNFDG) in body areas unaffected by respiratory movement were enrolled in this study. PET/CT examinations were performed on
the Biograph 16 HI-REZ (Siemens) scanner equipped with pico-3D digitalelectronics. PET images were reconstructed with the attenuation weighted
FORE-OSEM algorithm (2 iterations/8 subsets, 8mm FWHM Gaussian 3D
filter) on a 256x256 frame and sent to the treatment planning system Pinnacle (Philips) with the correspondent CT images. LN evaluated as positive
on PET scan were delineated as gross tumour volumes (GTV) first on CT(GTVCT) by two expert radiation oncologists and then on PET (GTVPET) images using an easily applicable method based on ATA. ATA was developed on
IEC phantom measurements and TS% depends on two parameters, the ratio
between maximum activity concentration in target and medium surrounding
background (TB)and target area (A), according to:A < 133 mm2 , TS% = 79.2
- 0.23 x A(mm2 ) + 48.7/TBA > 133 mm2 ,TS% = 36.6 + 68.2/TB.The algorithm requires the definition of the threshold on central slice of the target(observed in transverse, coronal, and sagittal view). From TB measure on
PET image, TS% is derived and applied to evaluate LNarea; radius is derived from the area and finally the volume can be calculated using sphericalmodel. Agreement between GTVCT as delineated by the two observers andbetween GTVCT and GTVPET were analyzed according to the method ofBland-Altman.
Results: All LN had a central area > 133 mm2 . Average TB was 12 ± 7(range 4 - 33) while TS% was 44 ± 5 (range 38 - 59). Average GTVCT
was 3.2 ± 3.1 ml (range 0.8 - 15.8 ml) and average GTVPET was 3.0 ±2.4 ml (range 1.0 - 12.4 ml). The mean difference between GTVCT and
GTVPET was 0.1 ± 0.8 ml with minimum and maximum difference of -0.7 ml
and 3.5 ml, respectively. We would expect most of the differences (limits ofagreement) between GTVCT and GTVPET to lie between -1.4 and 1.7 ml, as
shown by the Bland-Altman plot while the corresponding limits of agreement
between GTVCT as delineated by the two observers ranged from -0.6 and
0.5 ml (not shown).

Conclusions: This ATA allows the delineation of GTVs for LN on FDG-PET
imaging with accuracy. Its extension for primary tumors requires further development and validation.

S 356OTHERS

OTHERS927 poster
ASSESSMENT OF PLANNING TARGET VOLUME MARGINS BASEDON RANDOM AND SYSTEMATIC ERRORS: WITH AND WITHOUTCORRECTION PROTOCOLS
M. Djordjevic1 , B. Sorcini1
1

K AROLINSKA U NIVERSITY H OSPITAL, Department of Medical Physics andRadiation Safety, Stockholm, Sweden

Purpose: To determine the impact of correction strategies on required planning target volume margins. Data from daily on-line image registrations wereused to evaluate correction protocols.
Materials: Setup correction data for daily kilo-voltage 2D/2D on-line image
registrations with Varian On-Board Imager (OBI) were used to analyse random and patient systematic variations. The study includes data from 100
prostate, 64 cervical and 46 HeadandNeck cancer patients. The most important anatomical structures were outlined in the DRR images by physicians toaccurately match the target sites. Gold marker implants were used for daily
localisation of the prostate. Required PTV margins based on random andsystematic setup errors were estimated according to the margin formula M =2.5Σ + 0.7σ . Corrections of the patient systematic error based on the three
to five first fractions were simulated on the data set. The data was also compared with clinical correction protocols in terms of number of isocenter corrections, frequency of corrected directions and frequency of out-of-tolerance
in remaining part of treatment.
Results: The required margins for Head-and-Neck patients were 5.8 mm,
7.2 mm, and 5.8 mm in the lateral (LR), anterior-posterior (AP) and superiorinferior (SI) directions. With corrections based on the mean value of the fiveinitial fractions and a correction action level of 2 mm, the required margins
were reduced to 3.8 mm (LR), 4.6 mm (AP) and 4.0 mm (SI). Decreasing theaction level from 3 mm to 2 mm, did only show a small additional reduction of
the systematic error. For cervix cancers the required margins were reduced
from (13.2, 9.5, 8.3) mm to (9.9, 7.6, 7.8) mm in the (LR, AP, SI) directions,with an action level of 4 mm. Without applying corrections, the systematicand random components were equal, Σ = σ , in the pelvis region, while for
Head-and-Neck the systematic components was larger, Σ > σ , in all directions.Table 1. PTV margins, with no setup correction and with correction of
the systematic error based on the mean value of the five initial treatment fractions. The margin for the prostate includes internal movement and setup error
according to implanted gold markers.

geographical contributions to cancer nanotechnology research via biometric
literature search.
Materials: On 6 October 2010, a Medline search was conducted using the
National Library of Medicine’s search service "PubMed" to retrieve research
reports in cancer nanotechnology. Retrieval was limited to papers publishedfrom 1 January 2000 to 6 October 2010. "Nano", "Cancer", "radiation", "radiotherapy" and the country of interest were used as search phrases. Eachsearch was limited to a specific year using the "Limits" function incorporated
in the search engine. Data pertaining to the number of articles, date of publication and country of origin were analyzed. The number of published reports
was considered an index of research productivity.
Results: Five hundred and twenty three reports addressing cancer nanotechnology research were published from 2000 to 2010. The United States had
the greatest gross productivity of over the years with 196 (37.5%), followedby China with 60 (11.5%), South Korea with 50 (9.6%), Japan with 35 (6.7%),
Germany with 24 (4.6%), United Kingdom with 15 (2.9%), Canada with 14(2.7%), followed by India and Australia both with 11 published reports compromising 2.1% of global publication. Other world countries with less than
10 published reports include Sweden, The Netherlands, Spain, Denmark,Greece, Turkey, Singapore, Egypt, South Africa, Brazil, Iran and Chile. The
world output of cancer nanotechnology research increased progressively over
the years from 4 (0.8%) in 2000, 6 (1.1%) in 2001, 8 (1.5%) in 2002, 18(3.4%) in 2003, 31 (5.9%) in 2004, 47 (9%) in 2005 and 2006, 66 (12.6%)
in 2007, 77 (14.7%) in 2008, 109 (20.8%) in 2009 and 110 (21%) in 2010
to the time of this study. The research outputs of China and Korea haveincreased substantially over the past 3 years with 78% and 80% of the respective total number of reports published between 2007 and 2010. Thirty
three reports addressing radiotherapy-related cancer nanotechnology wereretrieved. Among those; radiobiology-related research was narrated in 6
reports (18%), radiation-related imaging strategies in 4 (12%), novel radiotherapy delivery techniques in 3 (9%), radiation toxicity studies in 2 (6%),
chemotherapy-radiotherapy interactions in 1 (3%) and radiation dosimetry in
1 (3%) report. The remaining 16 (49%) reports narrated various radiotherapyrelated nanotechnological advances.
Conclusions: These results provide crucial information on the worldwide geography of nano-related cancer research. The United States continues to play
the leading role in advancement of this branch of biomedical research possibly reflecting the huge resources involved in this field. China and South Korea
provide major and rapidly increasing research contributions. Lack of basic
research infrastructure, human expertise and funding appear to be significant issues pertaining to the lag of widespread boom in radiotherapy-related
nanotechnology research. Our study shows that cancer nanotechnology research is growing indicating strong global commitment, however, the inadequacy of funding -at least in some nations- appears to hinder more comprehensive global participation.
929 poster

feasible with a relatively longer-term survival. The results justify further investigation of higher dose radiotherapy using intensity modulated radiotherapy.

928 poster
BIBLOMETRIC ANALYSIS OF CANCER NANOTECHNOLOGYRESEARCH: ARE RADIOTHERAPY-RELATED APPLICATIONSLAGGING BEHIND
A. Salem1 , J. Khader1 , L. Y. I. Mula-Hussain1 , I. Jaradat1 , I. Mohammed2 ,S. Hashem1 , A. Al Mousa1
1
K ING H USSEIN C ANCER C ENTER, Amman, Jordan
2
K ING H USSEIN C ANCER C ENTER, Department of Radiation Oncology,
Amman, Jordan
Purpose: Nanotechnology is the science addressing manipulations of matter in the range of 1-100 nanometers. While the roots of this branch of science stretch back many years; the explosion of research activity has only
occurred within the last ten to fifteen years. Today, there is increasing optimism that nanotechnology -applied to oncology research- will bring significant advances in the diagnosis and treatment of cancer. As a consequence,cancer nanotechnology has been under intense development for applications
in cancer imaging, molecular diagnosis and targeted therapy. Analysis ofcancer-related nanomedical publications could be used to monitor research
progress and overall trends. This study provides an overview of the research
performance of major world countries in cancer nanotechnology with special reference to radiotherapy-related nanotechnology publications. We intend to evaluate the overall scientific research output and assess worldwide

REGIONAL LYMPH NODE METASTASIS
J. Wang1 , Y. Wang1 , Y. Wang1 , D. Tian1 , J. Yang1 , S. Zhu1 , C. Han1
1

930 poster
CHEMO-RADIOTHERAPY IN GLIOBLASTOMA MULTIFORME.
THE EFFECT OF MGMT PROMOTER HYPERMETHYLATION ON
SURVIVAL
P. R. Jampana1 , C. Blesing2 , N. Warner1 , O. Ansorge3
1

OXFORD C ANCER C ENTRE , C HURCHILL H OSPITAL, Oxford, United
Kingdom
OXFORD C ANCER C ENTRE , C HURCHILL H OSPITAL, Clinical Oncology,
Oxford, United Kingdom
3
OXFORD R ADCLIFFE H OSPITALS NHS T RUST, Department of NeuroPathology, Oxford, United Kingdom
2

Purpose: Glioblastoma Multiforme is a common and aggressive primarybrain tumour. The overall prognosis for patients with this tumour is poor.
Chemo-radiotherapy with concomitant and adjuvant Temozolomide gives patients the best chance of longer survival. The presence of MGMT promoter
hypermethylation has been shown to influence survival in these patients. Our
objective was to look at Overall Survival in patients having Radical Chemoradiotherapy and in particular those that were MGMT promoter positive.
Materials: We retrospectively looked at the survival of 59 patients treated inour centre, who received Radical chemo-radiotherapy over a period of 3 years
from March 2006 to March 2009. Patients received Temozolomide(75mg/m2)
daily during standard fractionation radiotherapy of 60Gy, followed by adjuvant
Temozolomide at a dose of 150-200 mg/m2, for 5 days of every 28 day cycle,for 6 cycles. The 59 patients were divided into 2 groups.Group 1 (20 patients) consisted of patients who were treated between March 2006 and June
2007. During this period, in our centre, due to funding constraints, radical
chemo-radiotherapy was mainly given to patients who were MGMT positive
while others had either radical radiotherapy alone or palliative radiotherapy orbest supportive care. We report those who received radical chemo radiotherapy, 75% of whom were MGMT positive. Group 2 (39 patients) were treatedbetween July 2007 and March 2009. In this group, MGMT status was notanalysed as Chemo-radiotherapy was given to all patients who were considered fit enough to receive it.
Results: We looked at the overall survival, one year survival and two year
survival for these patients.Group 1- The median survival for patients in thisgroup was 21.9 months with a 1 year survival of 75% and a 2 year survival of
50%. For comparison, during the same period, the median survival for MGMT
negative patients having radical radiotherapy alone was 12.5 months, with a
one year survival of 50% and no one surviving more than 18 months.Group
2- The median survival for patients in this group was 12 months with a 1 year
survival of 48% and a 2 year survival of 25.6%.

CANCER OF THE PELVIS: DEFINITIVE RADIOTHERAPY FOR
THE PATIENTS WITH ISOLATED RECURRENCE OF ABDOMINALPARAAORTIC LYMPH NODEK. Yahara1
1
UOEH, Department of Radiology, Kitakyusyu, Japan
Conclusions: Correction protocols, aimed to correct the mean error of thepatient, allow a reduction of the setup margin with a small amount of workload. However, image verification with appropriate intervals during the remaining part of the treatment is required to account for anatomical changes
and the uncertainty in the estimated mean error.

S 357

T HE F OURTH H OSPITAL OF H EBEI M EDICAL U NIVERSITY, Radiation
Oncology, Shijiazhuang, China

Purpose: To explore the prognosis factors of 3-dimensional conformal radiotherapy (3D-CRT) versus intensity modulated radiation therapy(IMRT) for
esopageal carcinoma with regional lymph node metastasis.
Materials: From January 2001 to December 2008, 112 patients with cervical or thoracic esophageal carcinoma with regional lymph node metastasis were retrospectively analyzed, 60 patients were in 3D-CRT group and
52 patients were in IMRT group, with a total dosage of 56Gy70Gy/2835 fx/5.67 weeks ( median 60Gy). Simultaneous integrated boost (SIB) technique
was used in 35 patients in IMRT group, with a prescribed GTV dosage was
2.2Gy/fx, prescribed CTV dosage was 2.1Gy/ fx, prescribed PTV dosage was
2.0Gy/fx. Concurrent chemoradiotherapy was given in 23 patients in 3D-CRT
group and 35 patients in IMRT group(χ2 =9.37p=0.002). It was given on thefirst week of irradiation: Calcium Folinate 200mg at days 1-5, 5-fluorouracil
500mg/m2 at days 1-5, cisplatin 12mg/m2 at days 1-5 or 25mg/m2 at days 1-3(LFP regiments), and repeated in every 4 weeks to a total 1-2 cycles during
the irradiation. Survival rates and itsrelated prognotic factors were evaluatedrestrospectively with SSPS 11.5 software.
Results: After the irradiation , as for short-term efficacy evaluation, complete response (CR) rate, partial response (PR) rate and no response (NR)rate were 33.9% (38/112), 64.3% (72/112) and 1.8% (2/112) respectively,
the rate of total efficiency(CR+PR) was 98.2%. In all the patients , the1-,2-,3-year overall survival rates were 62.49%, 39.37%, 23.67%, respectively; the median survival time was 17 months. The 1-,2-,3-year survival
rates and median survival were 51.67%, 32.80%, 18.61% and 12.4months
in 3D-CRT group and 75.00%, 46.73%, 40.05% and 17months in IMRT
group, respectively(χ2 =4.74p=0.030). The 1-,2-,3-year free-recurrence survival rates were 64.41%, 45.02% and 45.02% in 3D-CRT group and 72.21%,
58.67% and 58.67% in IMRT group (χ2 =2.27p=0.132). With uninvariate analysis, for patients with female, ages≤65, tumor located in cervical and upperthoracic, >5cm lesion length in barium esophagogram, ≤4cm the largest diameter of lesion in CT scaning image, T4 stage, or semi-liquid or liquid diet
before the irradiation, survival rate were higher in IMRT group than in 3D-CRT
group(p<0.05); but in patients with male, ages>65, tumor located in middle
and lower-thoracic, ≤5cm lesion length in barium esophagogram, >4cm thelargest diameter of lesion in CT scaning image, T1-3 stage, or normal diet
before the treatment, concurrent chemotherapy and prescribed dose of irradiation, survival rate were not different between IMRT group and 3D-CRT
group (p>0.05). Multivariate analysis revealed that the different diet and T
stage were independent prognostic factors.
Conclusions: Stage of primary tumor is still the most important prognostic
factor in esopageal carcinoma patients with regional lymph node metastasis
treated by 3D-CRT or IMRT technics. It seems that IMRT has some advantage for part of esophageal carcinoma patients in subgroup when comparedwith 3D-CRT. IMRT-SIB technique should be studied further to confirm thatit could improve efficacy by expanding sample size and accumulating clinicalexperience.
932 poster

Purpose: Some positive results have been reported for curative surgical resection in the patients with isolated abdominal paraaortic lymph node (PALN)
recurrence of pelvic cancer. However, the efficacy of definitive radiotherapy
as a salvage therapy has scarcely been reported in these patients. The purpose of our study was to evaluate the outcome of definitive radiotherapy for
isolated abdominal PALN recurrence in the patients with primary controlled
cancer of the pelvis.
Materials: Consecutive 24 patients with isolated abdominal PALN recurrence
who were treated between May 1993 and March 2009 were retrospectively
analyzed. The patients were included in this study if they were eligible toreceive definitive radiotherapy for abdominal PALN recurrence with primarycontrolled cancer of the pelvis without other distant/recurrent diseases. The
sites of the primary lesion were as follows: cervical cancer (n=11), endometrial cancer (n= 1), ovarian cancer (n=8), rectal cancer (n=1) and bladdercancer (n=1). Median time between the front-line therapy and radiotherapy
for isolated PALN metastases was 26 months. Median total irradiation doseof radiotherapy was 50Gy (range, 5061). Nine (38%) of 24 patients received
concurrent chemotherapy, and 6 (25%) of 24 patients also underwent adjuvant chemotherapy after the radiotherapy.
Results: Twenty-two (79%) patients had an objective tumor response (CR in
14 patients, PR in 5). The infield or marginal failure occurred in 3 patients(13%), while failure of outside of the irradiated field was recognized in 11(46%). Overall, progression-free and local control survivals at 5 years were65%, 25%, and 47%, respectively. Statistically significant prognostic indicators of overall survival rate were irradiation dose (more than or equal 51Gy)(p<0.0001), chemotherapy (p<0.0001), and time between front-line therapy
and radiotherapy (more than or equal 24 months) (p=0.03). The toxicities
were mild; neutropenia of Grade 3 was detected in one patient, and Grade 3
or higher non-hematologic toxicity was not observed.
Conclusions: Definitive radiotherapy for isolated abdominal PALN recurrence in the patients with primary controlled cancer of the pelvis may be

COMPARISON OF PENUMBRA IN THE SMALL RADIOSURGERY
FIELD SIZES BASED ON CIRCULAR CONE AND LINAC’S JAW WITHPIN POINT CHAMBER
M. Yarahmadi1 , M. Allahverdi2 , H. A. Nedaie3 , S. A. Vaezzadeh3
1
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Medical Physics andEngineering, Tehran, Iran Islamic Republic of2
T EHRAN U NIVERSITY OF M EDICAL S CIENCES R ADIATION O N, Tehran, Iran
Islamic Republic of3
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Tehran, Iran Islamic
Republic ofConclusions: The results show the effectiveness of chemo-radiotherapy
improving survival in patients with Glioblastoma Multiforme, in particular
those patients whose tumours express methylated MGMT promoter. Our results compare favourably with those of Stupp et al. (2005) who showed a
26% 2 year survival in those treated with chemo RT (regardless of MGMT
status). Routine checking of MGMT status should be practised as thiswill provide valuable prognostic information.Stupp et al. NEJM. 2005 Mar
10;352(10):987-96
931 poster
COMPARE THE PROGNOSIS OF THREE-DIMENSIONAL CONFORMAL RADIOTHERAPY (3D-CRT) VERSUS INTENSITY MODULATEDRADIATION THERAPY (IMRT) FOR ESOPAGEAL CARCINOMA WITH

Purpose: In stereotactic radiosurgery (SRS), a narrow beam penumbra isoften desired for producing steep dose fall-off between the target volume andadjacent critical structures. Due to limited source sizes, scattering effects andthe partial blocking of the beam source, the physical penumbra of the X-Knife
is often produced therefore measuring beam penumbra is more important. In
this work we report experimental measurements of beam penumbra of thesmall radiosurgery field sizes based on circular cone and Linac’s Jaw.
Materials: The small field sizes were produced by Varian Clinac-2100 accelerator’s Jaws and circular cone coupled to this linear accelerator. The side
length of square fields and diameter of circular fields were 5, 10, 20 and
30 mm. PTW Pinpoint was used for measured 80-20% and 90-10% beam
penumbra at a source to surface distance of 100 cm in water at 5cm depth.
The 6MV photon beam was investigated using 200 monitor units.
Results: The 90-10% beam penumbra for circular fields were obtained 2.71%- 1.73% - 4.04 and 26.33% smaller than square fields for field sizes 5 - 10 20 and 30 mm respectively. The 80-20% beam penumbra for circular fields
were obtained 5.32% - 2.48% - 4.52 and 31.72% smaller than Square fields
for field sizes 5 - 10 - 20 and 30 mm respectively.
Conclusions: It is found that circular cones reduced beam penumbra in all of

S 358OTHERS

OTHERSthe small field sizes and circular cones are necessary to create narrow beam
penumbra for using in SRS.
933 poster
COMPARISON OF VOLUME RENDERING TECHNIQUES FOR
TUMOR VISUALIZATION IN 3-D ULTRASOUND IMAGE VOLUMES
H. M. Overhoff1 , C. Sobotta1 , S. Maas1
1U NIVERSITY OF A PPLIED S CIENCES G ELSENKIRCHEN, Medical Engineering Laboratory, Gelsenkirchen, Germany
Purpose: 3-D ultrasound images can be examined e.g. by consecutive inspection of 2-D image slices in 3 orthogonal orientations or as a 3-D semitransparent volume. The latter can visualize the spatial relation of anatomicalor functional structures, if a proper assignment of gray scale to gray scaleand opacity values to the voxels, i.e. proper gray scale (GTF) and opacitytransfer functions (OTF) are applied for rendering. This rendering process
assumes parallel viewing rays from the computer screen through the entire
volume. The gray scale and transparency properties of all voxels along a ray
are projected onto one pixel on the screen.Most of such TFs exploit solely thevoxel’s gray scale value and therefore yield intuitively perceptible scenes only
if the voxels of different anatomical structures have different gray scale values like vessels in soft tissue.It was investigated, if TFs that map gray scaledifferences of spatially adjacent voxels, i.e. gradient data, onto gray scale(GGTF) and opacity values (GOTF) improve the visibility of anatomical structures significantly. The influence of the TFs on visualization was exemplarily
investigated for suspicious masses in a breast.
Materials: A MyLab70 ultrasound device (Esaote Europe B.V., Maastricht,
The Netherlands) was used to acquire 10 3-D ultrasound image volumes witha 3-D linear 8-13 MHz transducer of patients with at least a suspicious massin a breast. Each of the volumes consisted of about 350 individual 2-D ultrasound images.In the image volumes, the location of the suspicious mass
and its gray scale values were identified. If existent, further structures wereidentified that potentially obscured a direct spatial view through the image
volume onto this mass. 3-D visualizations were rendered as a (a) maxim
intensity projection (MIP). Here, all voxel keep their gray scale values, andtheir opacity is proportional to the gray scale values. During the rendering thevoxel with the maximal gray scale value on a parallel viewing ray is visualized.
Furthermore, GTFs, OFTs and GOTFs were interactively set and applied to
the volume before its MIP. The volume rendering was implemented in C using
the Visualization Toolkit library (Kitware Inc., Clifton Park, USA).The resultsof these three visualizations were rated w.r.t the unimpeded visibility of themass in cases when close-by anatomical structures of similar gray scale values existed.
Results: The figure shows a volume visualization sequence of one data set.
For the upper left subimage, a MIP was generated as a reference. The mass
is rarely visible. In the upper right subimage, a GTF is applied and improves
the mass’s visibility (dark gray volume) at still rare contrast. In the lower row a
GOTF finally makes the mass clearly visible due to high transparency of the
mass’s surrounding tissue in different viewing aspects.

Conclusions: The visibility of anatomical structure in 3-D ultrasound image
volumes can be improved by properly chosen transfer functions. This interactive procedure should be automated to improve clinical usability.

934 poster

936 poster

CONCURENT RADIOTHERAPY WITH CAPECITABINE AND MITOMYCIN IN ANAL CANCER - SINGLE INSTITUTION EXPERIENCE
N. Angelovska1 , B. Grozdanovska1 , N. Mitreski1

DOSE ESCALATION STUDY USING 4D CT PLANNING IN LOCALLYADVANCED PANCREATIC CANCER
G. Radhakrishna1 , M. collins1 , S. Wilson1 , D. Sebag-Montefiore1 , B.
Carey1 , S. Swift1 , K. Franks1 , J. Lilley2 , D. Smith1 , S. Kirwin1 , R.
Lindsay1 , H. Summers1 , A. Woolley1 , P. Byrne1 , N. Roberts1 , J. Sykes1 , A.
Needham1 , A. M. Crellin1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom
2
S T J AMES ’ S I NSTITUTE OF O NCOLOGY, Leeds, United Kingdom

1

I NSTITUTE OF R ADIOTHERAPY AND O NCOLOGY, Gastrointestinal Radiotherapy Unit, Skopje, Macedonia Former Yugoslav Republic ofPurpose: The aim of the study was to evaluate the efficacy and toxicity ofradiotherapy with concurrent mitomycin and capecitabine in patients with T3,
T4 anal carcinoma
Materials: 5 (five) patients with T3 and T4 anal (planocelular) carcinoma
received radiochemotherapy with capecitabine and mytomicin as neoadjuvant
treatment. Pelvic radiotherapy was given using a four field technique withmegavoltage photons. Pts received a total dose of 59,4 Gy in 33 fractions of
1,8 Gy. Capecitabine, 825 mg/m2, was administered concurrently, twice daily,
continuously, starting on the first day till last of the irradiation with pause forweekend. The first daily dose of capecitabine was administered in a periodof two hours before radiotherapy treatment, and the second dose was given
12 hours after the first one. Mitomycin, 10mg/m2, was administered as iv
infusion on the first day of irradiation.
Results: After 3 months follow-up on CT scan, partial response was observed in 3 pts, complete response in 1 patient confirmed with anal biopsy
and pathohystology and stable disease in 1 patient. In 3 pts with partial
response and in the patient with stable disease, surgery was performed 3
months after chemoradiation. As expected, gastrointestinal toxicities werethe most common adverse events. Diarrhea was experienced in all patients.
In 2 pts it occurred at grade 2, and in 3 pts at grade 3. Haematologic toxicity was mild, with leukocytopenia grade 1 in one pts, and thrombocytopenia
grade 2 also in one pts. Two pts had hemorrhage ex ano. Most of these
events occurred during the fourth week of the therapy. Four pts had skin toxicity presented as erythema in the perianal and inguinal region, but it can bealso attributed to the radiotherapy. There were no cases of hand-foot syndome.
Conclusions: Oral capecitabine plus radiotherapy demontrates equivalent
efficassy with PVI 5FU and predictible and favorable safety profile. As an oral
fluoropirimide, capecitabine acts like continuous 5 FU infusion. Respectivly,
concurrent capecitabine and radiotherapy is an alternative to PVI 5FU andirradiation. Administration of oral capecitabine simplifies chemoradiation andenables PVI adequate radiochemotherapy in institutions where protracted infusion is not available during to technical reasons.
935 poster

CONFIGURING THE MOSAIQ® ONCOLGY MANAGEMENT SYSTEMTO MEET LOCAL CLINICAL DEMAND.
J. Hirons1 , I. Stronach1 , K. Natarajan1
1
U NIVERSITY H OSPITAL B IRMINGHAM NHSFT, Medical Physics Imaging,
Birmingham, United Kingdom
Purpose: To safely and effectively enhance Impac Mosaiq® at University
Hospital Birmingham NHS Foundation Trust (UHB NHS FT), replacing an
existing Oncentra Visir® installation. We proposed utilising existing Trust IT
infrastructure, where appropriate, and presenting the Mosaiq® application
within a managed Microsoft Windows™ interface, suitable for routine local
clinical use.
Materials: Dedicated Virtual Local Area Networks within the Trust network infrastructure were used and corporate enterprise IT solutions adopted where
suitable. Required links to other specialties and information systems, such as
SRS, HDR and HIS etc. were established and additional external precautions
employed to enhance data security and to protect confidentiality. A locked
customised Windows™ interface was applied to Mosaiq® workstations to permit access to relevant clinical applications and utilities only. Individual user
rights within the Mosaiq® application were externally augmented and complemented by controls used to present explicit functionality to targeted locked
auto-login Windows™ accounts, and individual clinical Mosaiq® workstations.
Results: Additional configuration, by means of measures peripheral to theclinical application, effectively place constraints upon certain Mosiaq® tasks
from being carried out in inappropriate areas. Examples include controllingthe importation of digital photographs and restricting access to certain networked resources from within the Mosaiq® application to dedicated workstations. Since the user interface is locked, access to unnecessary functionality is denied and the risk of problems caused by staff inadvertently making
configuration changes has been eliminated. The Windows™ security model
employed has also successfully been applied to ProSoma® virtual simulation
workstations.
Conclusions: The customisation of dedicated Windows™ accounts, associated IT policies and the limited additional configuration of Mosaiq® workstations, improves the security, stability and effectiveness of the Radiotherapy
Service at UHB NHS FT. Compliance with documented clinical proceduresis enhanced by means of the external controls and restrictions applied, in
addition to the standard security provided within the Mosaiq® application.

S 359

Results: An overview of the results is presented in table 1. The magnetic field
does not influence the linearity or short term reproducibility of the dosimeters.All dosimeters show various magnetic field strength dependencies forthe two orientations.The Edge and Microlion appear to need an extra preirradiation of 17 cGy to achieve electron equilibrium after movement, or orientation change, in a magnetic field.For all devices the reading is influenced
to some degree by the orientation between the magnetic field and the device.
The Edge diode, Microlion and Pinpoint chamber are all suited for profile
measurements within the spatial accuracy of the MRI compatible water tank.

Purpose: Approximately 30% of patients diagnosed with pancreatic cancer
will present with locally advanced unresectable disease (LAPC). The prognosis for these patients remains poor. We reviewed the utility of 4D CT planningin these patients treated with chemoradiation (CRT). Improvement in radiotherapy planning techniques may have the potential for an escalation in radiation dose. We set out to evaluate thisMaterials: From February 2010, patients with LAPC suitable for CRT wereplanned using contrast enhanced (Intravenous and oral) 4D CT scanning. Patients were treated with concurrent Capecitabine and image guided radiotherapy to the pancreas to a dose of 50.4 Gy.Gross Tumour volume (GTV) was
outlined on all respiratory phases of imagesets generated by 4D CT with aradiologist(NCRN SCALOP study protocol). An Internal Target Volume (ITV)
was generated as a composite of all the GTV. This ITV was grown with 1to
1.2cm circumferential margin of 1.2 to 1.5 cm superior-inferiorly to produce a
PTV. We defined organs at risk constraints as Spinal Cord PRV (spinal cordwith 5mm circumferential margin) <40Gy, Liver V30 (volume of liver receiving 30Gy)<40%and combined kidney V20 (volume of kidneys receiving 20Gy
<30%) We reviewed the utility of escalating the radiotherapy dose to 55.8Gyusing a multi-field technique of four to seven coplanar beams and compared
it to our departmental standard four field technique.
Results: We identified 8 patients with pancreatic cancer who had 4D CT
scans to date. Tumour delineation was carried out in conjunction with a radiologist for all patients.PTV coverage was compliant with ICRU 62. We foundthe use of a multi-field technique at 50.4 Gy reduced the mean small bowel
V15 by 27% (range 136.1 cc to 628.0cc) and V45 by 14% (range 11.4cc to132.7cc) when compared to the departmental standard. With dose escalation to 55.8GY, the multi-field plan remained compliant with the organs at risk
constraints. The mean small bowel V15 was reduced by 9% (range 107 cc to397 cc) and the V45 was comparable (range 16.7cc to 151.9cc).
Conclusions: The utility of 4D CT planning and a multi-field technique may
enable Radiation dose escalation to 55.8 Gy. The application of 4D CT planning and dose escalation in LAPC warrants further study
937 poster
DOSIMETER CHARACTERISATION IN A MAGNETICDOSIMETRY FOR A 1.5 T MRI-LINAC HYBRID
K. Smit1 , J. Kok1 , B. Raaymakers1 , J. Lagendijk1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands

FIELD;

Purpose: At the UMC Utrecht (The Netherlands) we built an MRI-linac: an
integration of a closed bore 1.5 T Philips MRI scanner and a 6MV Elekta
linear accelerator.The isocenter of this system lies inside the bore of the MRI,
meaning dosimetry will take place in a 1.5T magnetic field possibly influencing
dosimeter characteristics. Here we will investigate 4 dosimeters; Edge diode(Sun Nuclear), Microlion liquid filled ionization chamber (PTW) and air-filled
ionization chambers Pinpoint IC-04 (Rosalina Instruments) and Farmer NE
2571 (PTW).
Materials: The following characteristics were investigated:
1. The influence of the magnetic field on the dose-response is measured
for two irradiation orientations using an electromagnet at a clinical accelerator. Magnetic field strength was varied between 0.0 T and 1.2
T, in steps of 0.1 T. With these dependencies the influence of a 1.5 T
field can be estimated.
2. The linearity and short term reproducibility in a 1.5 T magnetic field
are determined for all dosimeters, to gain insight into the reliability ofthe dosimeter.
3. A possible significant discrepancy between the average doseresponse and the dose-response for the first applied dose after movement, or rotation, or both, in a 1.5 T magnetic field was investigated.
This indicates if additional pre-irradiation is necessary for profile measurements.
4. The influence on the dose-response due to a change in orientation between the dosimeter and magnetic field or radiation beam, was measured in 10◦ steps for a total 180◦ rotation.
The Edge diode, Microlion and Pinpoint chamber are used to measure Percentage Depth-Dose (PDD) profiles and lateral profiles in a water tank withsteps of 5 mm (3 mm for penumbra region).

Conclusions: All dosimeters need a correction factor for the magnetic field
when performing absolute dosimetry. For relative dosimetry, the Pinpoint IC04 chamber appears to be most suited, because of its stability, reproducibility,
and relative insensitivity to magnetic field influences.
938 poster
EFFECTS OF PTEN STATUS ON POLY (ADP-RIBOSE) POLYMERASEINHIBITION IN ADDITION TO RADIATION AND TEMOZOLOMIDE IN
GLIOBLASTOMA
E. Hlavin Bell1 , D. Patel1 , K. Palanichamy1 , A. Chakravarti1
1
T HE O HIO S TATE U NIVERSITY, Department of Radiation Oncology,
Columbus, USA
Purpose: Inhibition of poly (ADP-ribose) polymerase (PARP), a DNA repair
enzyme activated by genotoxic stress, represents a potential strategy to enhance the cytotoxic effects of radiation therapy (RT) and alkylating agents.

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The efficacy of PARP inhibition under treatment conditions of RT plus temozolomide (TMZ) for glioblastoma (GBM) has not been previously reported,
therefore we sought to determine the effects of PARP inhibition as well as themolecular determinants of response to PARP inhibitors in combination withstandard treatment of GBM.
Materials: In the present study, PJ-34, a highly potent PARP inhibitor, wasused to investigate the effects of PTEN status on PARP inhibition in combination with RT and TMZ using in vitro and in vivo models of GBM. First, two
primary GBM cell lines that lack PTEN expression and two primary GBM cells
lines that express PTEN were utilized to determine if PTEN status affects theefficacy of PARP inhibition in combination with RT and TMZ. Next, DNA damage and ATP levels were measured after the addition of a PARP inhibitor to
RT and TMZ with respect to PTEN status. The role of glucose metabolism
and PI3K/ AKT signaling in the response to PARP inhibition was then characterized in correlation to PTEN status. Finally, a U87-MG xenograft model wasused to validate our in vitro findings.
Results: Cell lines lacking PTEN were sensitized to PJ-34 in the setting of RT
plus TMZ, whereas PTEN expression was associated with resistance. AKT
activation was higher in resistant cell lines and was associated with increased
ATP levels. Additionally, forced expression of PTEN conferred resistance toPJ-34. Treatment with the glycolytic inhibitor 2-deoxyglucose (2-DG) or thephosphatidylinosotide-3 kinase (PI3K) inhibitor LY294002 sensitized resistant
PTEN-expressing cell lines to PJ-34 suggesting PI3K/AKT signaling is likely
responsible for resistance in PTEN positive cells. The therapeutic benefits of
PARP inhibition observed in PTEN-null cell lines may be dependent on RT, as
treatment with TMZ alone prevented sensitization.
Conclusions: In summary, PTEN status may be a promising marker to identify tumors that will respond to PARP inhibition when administered with TMZ
and RT. Our findings suggest that the ability of PARP inhibitors, such as PJ34, to enhance the anti-tumor effects of RT and TMZ is highly dependent on
the equilibrium between PARP’s pro-survival (increased PI3K/AKT signaling)
and pro-death (increased DNA damage) functions. To this end, we are thefirst to report that the ability of PARP inhibition to enhance TMZ and RT response depends on the proteomic profile of GBM tumors, especially PTEN
status.
939 poster
EFFECTS OF RADIATION-INDUCED ALPHAVBETA3 INTEGRINMODULATION ON CILENGITIDE EFFICIENCY IN PEDIATRIC
GLIOMA CELLS
P. Leblond1 , S. Meignan2 34 , F. Le Tinier2 , A. Dewitte2 , N. Wattez2 , E.
Lartigau5 , A. Lansiaux2
1
C ENTRE O SCAR L AMBRET, Lille, France
2
C ENTRE O SCAR L AMBRET, Laboratoire de pharmacologie antitumorale,
Lille, France
3
I NSERM U837 TEAM 4, Lille, France
4
IRCL, Lille, France
5
C ENTRE O SCAR L AMBRET, Department of Radiotherapy, Lille, France
Purpose: Despite the conduct of numerous clinical trials in pediatric cancers,
the prognosis for children with high grade gliomas (HGG) remains poor, indicating a critical need for new treatments. Cilengitide (EMD 121974, Merck
KGaA, Germany), a new compound in early clinical development, is a selective antagonist of αvβ 3 and αvβ 5 integrins, known to be involved in cell adhesion, tumor growth, angiogenesis and metastasis development. The aim ofour study is to evaluate the direct efficiency of cilengitide in combination withionizing radiation on pediatric glioma cell lines and to determine its mechanism of action in these specific glioma cells.
Materials: We used a wide tumor cell panel including 3 high grade (SF188,
KNS42, UW479) and 2 low grade (Res259, Res186) pediatric glioma celllines compared to the prototypic adult HGG cell line U87MG. Previous study
revealed various αvβ 3 expression levels but no correlation with the tumor
grade. As expected, the pediatric cell line UW479, which doesn’t express
αvβ 3, presented no sensitivity to cilengitide. All other pediatric cell lines, expressing αvβ 3, were sensitive to cilengitide. We previously demonstrated ahigher cytotoxicity of cilengitide in pediatric than in adult glioma cells. Cilengitide action on glioma cells appeared not only dependent of αvβ 3 expression
but also of their sensitivity to anoikis, two properties found in the majority ofpediatric cell lines. Albert et al [1] reported that ionizing radiation could induce
the expression of αvβ 3 and αvβ 5 integrins in endothelial and non-small-celllung cancer models.
Results: First of all, we show the impact of different doses of ionizing radiation on αvβ 3 integrin expression levels in our pediatric glioma cell lines.
Then, irradiated cells are treated with cilengitide using different schedules.
Cell detachment assay will be performed and we will try to correlate the biological effect of cilengitide with the radiation-induced modification of the αvβ 3integrin expression level. The cytotoxicity of cilengitide used as a single agent
and in combination with ionizing radiation will be demonstrated by MTS assay
on pediatric cell lines and compared with the adult HGG cell line. We will also
try to explore the potential use of cilengitide as a radiosensitizer.
Conclusions: The potential modification of αvβ 3 integrin expression level
following ionizing radiation could lead to an increase of the cell detachment
induced by cilengitide in the pediatric glioma cell lines, and to a synergy between these two therapeutic modalities. Future in vivo experiments should

confirm these expected results in pediatric glioma orthotopic xenografts models.[1] Albert et al., Integrin alpha V beta 3 antagonist cilengitide enhances efficacy of radiotherapy in endothelial cell and non-small-cell lung cancer models. Int J Radiat Oncol Biol Phys, 2006
940 poster
EVALUATION OF COMBINED TEMOZOLOMIDE AND HIGH LINEARENERGY TRANSFER RADIATION IN GLIOBLASTOMA CELL LINES
L. Barazzuol1 , N. Burnet2 , R. Jena3 , J. Jeynes1 , M. Merchant1 , K. Kirkby1 ,N. Kirkby4
1
U NIVERSITY OF S URREY, Ion Beam Centre, Guildford, United Kingdom
2
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Cambridge, United Kingdom
3
A DDENBROOKE ’ S H OSPITAL, Cambridge, United Kingdom
4
U NIVERSITY OF S URREY, Faculty of Engineering and Physical Sciences,
Guildford, United Kingdom
Purpose: Radiotherapy is a valuable post-operative treatment in patients withglioblastoma (GBM), with dose an important determinant of tumour control.
High linear energy transfer (LET) radiation offers superior biophysical properties over conventional radiotherapy and may have a great potential for treating
radioresistant tumours like GBM. However, very little pre-clinical data exists
on the effects of high LET radiation on GBM cell lines and moreover on theconcomitant application of chemotherapy. This study investigates the in vitro
effects of temozolomide (TMZ) in combination with low energy proton andalpha-particle radiation in cell lines from high-grade brain tumours.
Materials: Human GBM LN18 and U87 cell lines were treated with either
conventional X-ray, proton (LET 12.9 keV/µm), or alpha-particle (LET 98.24
keV/µm) radiation concurrently with 25 µM TMZ. The effects of TMZ on theradiosensitivity were evaluated using clonogenic assay, immunodetection ofphosphorylated histone H2AX (γ -H2AX), and cell growth analysis.
Results: The relative biological effectiveness (RBE) at 10 % survival increased as LET increased. No significant difference was noticed between
X-rays and protons, with RBE values ranging from 0.95 to 1 for LN18 andU87 cell lines, respectively. Alpha-particles showed an increased RBE in bothcell lines (1.8-1.9). TMZ, independently of the quality of radiation, increased
cell killing in the O6 -methylguanine DNA methyltransferase (MGMT)-deficient
U87 cell line. In contrast, TMZ provided no therapeutic enhancement in the
MGMT-expressing LN18 cell line. The residual number of γ -H2AX foci at 24h after treatment with radiation and concomitant TMZ was found to be lower
than or equal to that expected by DNA damage with either of the individual
treatments.
Conclusions: These results suggest that TMZ in combination with radiation
causes additive cytotoxicity regardless of the radiation quality. Nevertheless,particle therapy combined with chemotherapy may offer a promising alternative with the additional benefit of a more precise dose distribution and no extra
normal tissue toxicity.
941 poster
EXPERIENTIAL LEARNING OPPORTUNITIES IN RADIOTHERAPYDEPARTMENT IN CORK UNIVERSITY HOSPITAL (CUH) COMPAREDTO THE EUROPEAN TRAINING STANDARDS
Z. Ali1
1
WATERFORD R EGIONAL H OSPITAL, Radiology, Waterford, Ireland RepublicofPurpose: This study aims to identify the learning opportunities through theexposure of the non-consultant doctors to the work throughput and casemix in the bacground educational environment in Radiotherapy department
in Cork University Hospital (CUH). CUH provides radiotherapy services to acatchment area of over one million population and is the second biggest public department in Ireland. workload and infrastructure are compared to theminimum requirement that meet the standards of the European core curriculum.
Materials: The study describes the workload, casemix, infrastructure, equipment, staffing, learning resources and educational activities and environment.
The workload and case mix was extracted from the electronic database (LANTIS) and stratified by patient gender, treatment intent (radical vs. palliative),
treating consultant and tumour site. Tumour sites were further stratified int
common, frequent and rare cases according to the frequency of the presentation of new cases to the department weekly, monthly or less frequent, respectively. All these aspects were compared to the European core curriculum
and minimum infrastructure required for training departments.
Results: The department delivered services to 4619 patients over three
years between July 05 -June 08 including 3109 newly referred patients,
treated by four cunsultant lead medical teams, utilizing one conventional andone CT simulators and four linear ccelerators, one superficial treatment unit,
one brachytherapy unit and a radioactive treatment isolation unit. The department had access to all medical and allied health professionals services
within CUH and to all educational facilities and resources resources affiliatedto University College Cork (UCC) medical complex. Of the newly referredcases 53% were male patients vs. 47% females and 68% were treated withradical intent compaared to 32 % of patients treated with palliative intent intheir first visit. Common tumour sites included Breast, Prostate, Skin andpalliative bone metsastasis. Frequent tumour sites included rectal cancers,
uterine cervical and endometrial tumours, primary brain tumours, testicularseminoma, and palliative brain and spine metastasis, and palliative primarylung cancers. broad spectrum of less frequent cases were found to rpresent
cases seen at a frequency of less than 20 per year.
Conclusions: The Infrastructure, treatment planning and delivery equipment, staffing, and access to other specialty services and educational resources were found to meet the minimum criteria defined for radiotherapy
training in europe. The workload and case mix allows trainees to fulfill therequired standards. more organisd protected learning time on weekly basis
is required in addition to more structured training format to increase exposure to rare cases through the three years of training is required. Continuous
development in education and training need to go hand-in-hand with the technology development that took place in the fields of planning and delivery ofRadiotherpy over the last three decades.
942 poster
GAMMA KNIFE RADIOSURGERY (GKRS) IN THE MANAGEMENT OF
PARKINSON’S DISEASE AND ESSENTIAL TREMOR : LONG-TERM
FOLLOW-UP REPORT OF 196 CASES
R. Mojica1 , R. Mark1 , H. Smith1 , R. Akins1 , M. Nair1
1

J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, USA

Purpose: Management options for tremors secondary to Parkinson’s Disease (PD) and Essential Tremor (ET), include medications, Deep Brain Stimulation (DBS), Radiofrequency (RF), and Gamma Knife Radiosurgery (GKRS).
Results with GKRS have compared favorably to DBS and RF with respect totremor relief and complications. We report our updated long-term results with
GKRS in the treatment of tremors.
Materials: Between 1991 and 2010, 196 patients underwent MRI Scan targeted GKRS thalamotomy for medically refractory tremors secondary to PD(n = 120) and ET (n = 76). The target was the Ventralis Inter-Medius (VIM)
nucleus. The target received between 140 Gy in a single shot prescribed to
Dm using the 4 mm collimator. Treatment planning was accomplished thru
the Leksell Treatment Planning System. Pre-operative and post-operative
blinded assessments were performed by a team of independent examiners.
The Unified Parkinson’s Disease Rating Scale and Clinical Rating Scale for
Tremors was used to score tremors.
Results: With a median follow-up of 7 years (range 2-19 years), 82.6%(161/196) of patients had significant, or complete resolution of tremors. In
patients with PD, 81.7% (98/120) had near or complete tremor resolution, vs.
82.9% (63/76) with ET. There was no statistically significant difference by the
Fisher’s Test (p = 1.0). Five patients experienced MRI proven edema andtransient hemiparesis and speech difficulty. In four patients, the deficits wereresolved on high dose steroids. The 4th patient required high dose steroids
and hyperbaric oxygen for resolution of deficits and edema. There were nocases of hemorrhage, infection, or death.
Conclusions: GKRS thalamotomy to the VIM nucleus provides favorable results, both in tremor relief and complications, for patients with medically refractory tremors secondary to PD or ET. Furthermore, these results compare
favorably to DBS and RF, with regard to tremor relief, complications and cost.
In view of these long-term tremor resolution results, low complication risks,and cost savings, GKRS should be considered as a primary initial treatment
option in medically refractory tremors. The optimal dose with minimal complications, is 140 Gy.
943 poster
GAMMA KNIFE RADIOSURGERY (GKRS) IN THE MANAGEMENT
OF TRIGEMINAL NEURALGIA (TN) : MEDIAN 10 YEAR FOLLOW-UP
OF 545 PATIENTS
K. Thompson1 , R. Mark2 , R. Akins3 , M. Nair4
1

J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology and Image-applied Therapy, Lubbock, Texas, USA
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, USA
3
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology Molecular Radiation Sciences, Lubbock, Texas, USA
4
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Lubbock, Texas, USA

2

Purpose: Gamma Knife Radiosurgery (GKRS) has been used successfully inthe treatment of Trigeminal Neuralgia (TN). Results have compared favorably
to surgical procedures with respect to pain relief and complications. We report
our updated long-term results with GKRS in the treatment of TN.
Materials: Between 1991 and 2010, 545 patients with medically refractory
typical TN were treated with GKRS, and have not been lost to follow-up.
Prior neurosurgical intervention had been performed in 30.3% of the patients(165/545), with a total of 374 procedures. All patients had typical TN. GKRS

S 361

was given to the cranial nerve V entry root zone into the brainstem. Targeting
was defined by CT and MRI Scans, and inversion recovery MRI, utilizing axial, coronal and sagittal images. Treatment planning was accomplished thru
the Leksell Treatment Planning System. The prescribed doses ranged from70 to 90 Gy prescribed to Dm, in one shot using the 4 mm collimator, with the
20% Isodose line just touching the brainstem. Response to treatment was defined as excellent (no pain, off analgesics), good (no pain, with analgesics),
and poor (continued pain despite analgesics). Response to treatment wasrecorded in interviews conducted by a Gamma Knife Nurse.
Results: With a median follow-up of 10 years (range 5-19 years), 53.9%(294/545) of patients reported an excellent result, and 22.9% (125/545) a
good result after GKRS. There was a dose response, with 55.7% (68/122) ofpatients reporting an excellent or good response after 70 Gy, compared to80.8% (207/256) at 80 Gy, and 86.2% (144/167) at 90 Gy (p <0.01). Temporary ipsilateral facial numbness occurred in 18.7% (102/545), and permanent
facial numbness in 5.3% (29/545). Loss of corneal reflex occurred in 1.7%
(9/545), and painful dysesthesias in 2.9% (16/545). There have been threecases of anesthesia dolorosa. There was a dose response in facial numbness, with temporary numbness occurring in 6.5% (8/122) at 70 Gy, 17.6%(45/256) at 80 Gy, and 29.3% (49/167) at 90 Gy (p<0.01). Permanent numbness occurred in 2.5% (3/122) at 70 Gy, 4.3% (11/256) at 80 Gy, and 9.0%
(15/167) at 90 Gy (p<0.01).
Conclusions: GKRS offers favorable results, both in pain relief and complications, compared to surgery in the management of medically refractory
TN. In view of these long-term good pain relief and low complication risks,
GKRS should be considered as a primary initial treatment option in medically refractory TN. The optimal dose with maximum pain relief and minimal
complications, appears to be 80 Gy.
944 poster
GAMMA KNIFE RADIOSURGERY FOR THE TREATMENT OFNON-SURGICAL CYSTIC CEREBRAL METASTASES
P. Goetz1 , S. Lwu1 , M. Aryaee1 , E. Monsalves1 , J. Ebinu1 , N. Laperriere2 ,C. Menard2 , M. Bernstein3 , G. Zadeh4
1
TORONTO W ESTERN H OSPITAL - U NIVERSITY H EALTH N ETWORK, Divisionof Neurosurgery, Toronto, Canada
2
P RINCESS M ARGARET H OSPITAL, Department of Radiation Oncology,
Toronto, Canada
3
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO, Divisionof Neurosurgery, Toronto, Canada
4
U NIVERSITY H EALTH N ETWORK, Toronto, Canada
Purpose: Treatment options for cystic cerebral metastases include surgicalaspiration/resection, whole-brain radiation therapy (WBRT), and stereotactic
radiosurgery (SRS). Larger cystic lesions are regarded as unsuitable for SRS:
higher radiation doses required carry an associated risk of radiation toxicity
and the non-cellular component may not respond to radiation. Such lesions
often require surgery. We aimed to assess the role of Gamma Knife Radiosurgery (GKRS) in the treatment of non-surgical cystic brain metastases.
Materials: We reviewed a prospectively maintained database of brain metastases patients treated at our institution between February 2006 and July 2009.
223 consecutive patients with brain metastases underwent GKS. Lesions witha greater and less than 50% cystic component were identified. Clinical, radiological and dosimetry parameters were reviewed to establish the response
to SRS and identify potential predictive factors of response
Results: 57 lesions in 40 patients were analyzed. The primary cancer was
lung, breast and other in 47%, 16% and 37% respectively. 52% of the patientswere RPA Class I, the remainder class II. Mean tumour volume was 4.4 ml(range 0.1123.18 ml). Mean prescription dose was 20.1 Gy (range 15-24
Gy). Mean follow-up was 12.5 months (range 1.8-56). Mean conformality
index was 1.6 (range 0.83-3.2). Local control rates were 94, 87, 72 and 51%
at 3, 6, 12, and 18 months respectively; they were superior in lung compared
to non-lung subtypes and unaffected by percentage of cystic component.
Conclusions: These results support the use of GKRS in the managementof non-surgical cystic metastases despite a perceived poorer response in thereported literature. Our local control rates are comparable to a matched cohort of non-cystic brain metastases. Tumour subtype was as predictor of
response.
945 posterGAS ELECTRON MULTIPLIERS (GEM) DETECTOR - A NOVELRADIOTHERAPY IMAGING DEVICE: GEM VERSUS AMORPHOUS
SILICON PANELS
B. Mitterlechner1 , S. Huber2 , M. Mooslechner2 , F. Sedlmayer12 , H.
Deutschmann21
1
U NIVERSITY C LINIC S ALZBURG, University Clinic for Radiotherapy andRadio-Oncology, Salzburg, Austria
2
PARACELSUS M EDIZINISCHE P RIVATUNIVERSITÄT, Institute for Researchand Development on Advanced Radiation Technologies, Salzburg, Austria
Purpose: Todays standard in electronic portal imaging devices (EPID) as

S 362OTHERS

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used for kV and MV imaging applications in radiotherapy is amorphous silicon (aSi:H) flat panel technology. While new aSi:H panels provide relatively
good MV images, the quality and dosimetrical usefulness of devices suffers
significantly from radiation damages under normal clinical use. After average
life spans of 18 months, detectors have to be replaced. A novel flat panel
imaging technology, based on gas electron multipliers (GEMs), is promisingunlimited life span due to increased radiation hardness.
Materials: A new GEM detector was installed on a clinical linear accelerator(retro-fit), and integrated in our software open-radART (a record and verify
system with fast image feedback loops to enable robotic applications in adaptive IGRT on conventional linacs). In several test plans, we compare images
from the GEM detector with the aSi:H flat panel devices. Focus is set on exact
specification of framerate, digital quantum efficiency, linearity of response todoserate, spatial resolution (MTF), temperature behaviour, ghosting (imagelag) and aging / radiation hardness. Besides phantom studies, first clinicalimages of the GEM detector are captured.
Results: The clinical test environment was successfully implemented and alltest cases were performed in this setting. At a first glance, 16 bit image quality
is comparable to that of aSi:H imaging devices with the advantage of higher
possible framerates of the GEM panel (20 Hz vs. 2 Hz). Ghosting effects havenot been seen with GEM (intrinsic: no trapped charges), digital quantum efficiency (SNR at lower doses per frame) is significantly increased compared
to aSi:H. Although pixel size and active area are comparable, depending on
adjustable high voltage settings on the GEMs, the spatial resolution (MTF)
can be slightly lower compared to aSi:H technology. The GEM system appears to be stable, and re-calibration intervals are reasonable. However, longterm follow up data of radiation hardness in a typical clinical setting is not yet
available.
Conclusions: Relating to the measurement results, the GEM detector has
proven its potential to be a suitable imaging device in radiotherapy. However,further investigations need to be done to gain more expertise on tuning of
the new detector’s properties and to quantify aging effects due to radiation
damages.
946 poster
GLIOBLASTOMA IN ELDERLY: IS ADJUVANT RADIOCHEMOTHERAPY EFFECTIVE AND FEASIBLE?
A. Fiorentino1 , C. Chiumento1 , A. M. Mileo1 , V. Fusco1
1
IRCCS/CROB, Department of Radiation Oncology, Rionero in Vulture,
Italy
Purpose: Glioblastoma (GBM) is frequent among elderly patients (>65yars).
The Purpose of this retrospective study was to evaluate the feasibility and theeffective of Standard Radiochemotherapy (RTCHT) in GBM elderly patients.
Materials: Patients (pts) >65 yrs old with histological proven GBM (WHOgrade IV); were retrospectively evaluated. Patients received a surgical resection or biopsy and standard RTCHT with TMZ. The Clinical Target Volume
was defined as surgical bed + residual tumor + oedema + 0.5 cm and thePlanning Target Volume was defined as CTV + 0.7 cm. RTOG scale wasused to define acute toxicity.
Results: From March 2005 to June 2010, 27 GBM patients (pts) >65 yrs
were treated in our Institution (21 pts > 70 yrs). Fourteen are female and
13 male. Eight pts (29.6%) received a complete resection. After a medianfollow-up of 27 (range 3-65) months, median progression-free survival (PFS)
was 7 months (mts) and median Overall Survival (OS) was 12 months. Extent
of resection (p:0.03) and RPA class (p:0.05) correlated with OS. At multivariate analysis only the extent of resection was a significant prognostic factor(p:0.032).During RTCHT toxicity was mild, thrombocytopenia G3-4 occurredin 3 pts and Neurological toxicity G3-4 in 2 pts.
Conclusions: In conclusion, our data suggest that the association of RT with
TMZ could be considered as a safe and effective strategy to treat GBM in
elderly pts.
947 poster
HAS COMBINED MODALITY TREATMENT OF GLIOBLASTOMA
MULTIFORME CHANGED THE PATTERNS OF PROGRESSION?
G. Ryan1 , A. Gunjur2 , Y. Taouk3

to analyse the pattern of progression of GBM in our institution, to guide us in
future research and treatment protocols.
Materials: Patients with GBM treated as per Stupp protocol between October 2004 and August 2009 at the Peter MacCallum Cancer Centre in Melbourne were reviewed retrospectively. Sixty-eight eligible patients with complete follow-up were identified, of whom 54 were found to have progressed following treatment. MRI scans at progression and original radiotherapy plans
were available for 47 patients, and were fused in the radiotherapy planningsystem and analysed for site(s) of progression.
Results: There was an over-representation of males and patients over 60
years in our patient group (66% and 38% respectively) compared to the Stupp
study population. Coverage of site(s) of progression by the radiotherapy planning target volume was defined as: central >95% coverage, in-field >80-95%,
marginal 20-80%, and out-offield <20%. In our patient group 77% of progressions were central, 15% in-field, 6% marginal and 2% out-of-field. Given thesmall number of out-of-field recurrences, no temporal trends could be identified. Overall survival for the cohort was 11.6 months, with the 1 and 2 year
survival rates 50% and 18%.
Conclusions: There is no evidence of an increase in out-of-field progressions in our patient group. The relatively unfavourable demographics of thegroup may have contributed to this negative result. Further patient data will
be collected prospectively to address potential biases, and will be correlatedwith MGMT methylation status and newer imaging modalities.
948 poster

Purpose: More than 90% of patients with glioblastoma multiforme (GBM)
treated with adjuvant radiotherapy alone post-surgery progress within 2cm of
the enhancing tumour/surgical cavity, and this information is currently used indefining radiotherapy field margins. With the introduction of combined modality adjuvant treatment incorporating temozolomide chemotherapy (the "Stupp
Protocol"), there is emerging literature suggesting that the risk of progression
beyond these margins is substantially increased. This study therefore aims

950 poster
IMPLEMENTATION OF A WEB BASED ELECTRONIC CHEMOTHERAPY PRESCRIBING AND PATIENT RECORD SYSTEM IN A UK
CANCER NETWORKC. Blesing1 , D. Marshall-Searson1 , S. Coutts2 , A. Barkwith2 , N. Stoner1 , J.

Purpose: The DAVID is a harp-style transmission detector that is attached tothe accessory mount of the collimator of the linac. The DAVID has a signal
wire for each leaf pair in the leaf bank giving it the potential to perform invivo dosimetry on advanced treatment deliveries. Different versions of the
DAVID are available for different designs of MLC. Initial work has been done tocharacterise the response of the DAVID. The results have been encouraging
with the DAVID response varying linearly with delivered dose and behaving
predictably with field size.
Materials: The DAVID phantom was attached to the collimator of an Elekta
Synergy linac with an MLCi2 head. The position of the DAVID device within
the mount was adjusted until the detection wires were aligned with the MLC
leaves. A PTW semiflex chamber was placed at 10 cm deep at the isocentre
in a WTe solid water phantom. The David device was irradiated with square
fields of varying size and monitor units. Simultaneous measurements weretaken of the signal generated by the DAVID device and the dose delivered tothe isocentre
Results: Figure 1 shows the linear relation ship between delivered dose and
DAVID response for a constant field size. The relationship between DAVID
response and field size is slightly more complicated but can be described bya simple power law.

Pattinson3 , S. Moule4 , F. Ma2 , R. Furlong2 , D. Gray5 , K. Enwright5
OXFORD C ANCER C ENTRE , C HURCHILL H OSPITAL, Department of
Oncology, Oxford, United Kingdom
2
T HAMES VALLEY C ANCER N ETWORK, Oxford, United Kingdom
3
B UCKINGHAMSHIRE H OSPITALS NHS T RUST, Department of Haematology
4
H EATHERWOOD AND W EXHAM PARK NHS F OUNDATION T RUST, Department of Haematology
5
VARIAN M EDICAL S YSTEMS
1HDR BRACHYTHERAPY IN SKIN CANCERS: TARGET DETERMINATION AND OUTCOME VERSUS CONVENTIONAL RADIOTHERAPY
F. Piro1 , R. Siciliano2 , D. Cosentino1 , P. Indrieri1 , L. Ziccarelli1 , P.
Ziccarelli1 , L. Marafioti1
1
O SPEDALE M ARIANO S ANTO, Department of Radiotherapy, Cosenza, Italy
2
O SPEDALE M ARIANO S ANTO, Fisica Sanitaria, Cosenza, Italy
Purpose: Brachitherapy in skin cancers is a interesting alternative to conventional radiotherapy because offers personalized treatment (also in multisite cancers) and due to new fractionation used in our Center the treatment
time is shorter than conventional RT. Otherwise the leterature data for thesetreatment are few. So we performed this rewiew to evaluate outcome, toxicity
and or target missing in patients treated with high dose rate brachytherapy,
and with minimum follow up of 60 months.
Materials: From August 1999 to September 2010, 118 consecutive pts. withskin cancer (20% squamous cell) (5% with cancer larger >4 cm) were enrolled
in this perspective study: HDR treatment consisting of twice-daily fractionation of 350 cGy each, 6 hour apart final dose delivered 49 Gy as esclusive
modality or as postoperative treatment for positive margins; as postoperative treatment for squamous cell with clear margins the final dose deliveredwas 42 Gy. To provide the maximum coverage of the tumor the implants
were performed with afterloading spaced (at least 1 cm) catheters embedded in personalized surface molds or interstitial implant both planned with asemi-3-D technique aided by simulator. Radiopaque markers for target definition around the cancer were obbligatory (minimum space 5 mm maximum 10mm). So implant dosimetry was performed as 100% of prescription at eachskin marker. The follow up consisted in clinical examination of each cancer
site. We studied the pts. with a minimum follow up of 5 years. For failurecases a rewiew of dosimetry was performed.
Results: The eligible pts. were 93, the median follow up 84 months (range
60-96). The cosmetics results were poor in 6% of cases; the only important
toxicity was a telangectasia of the skin. The local relapse were 10% (9 cases)
especially for bulky cases (6), for 3 of these cases a full-dose reirradiation
was performed after the dosimetry rewiew without severe toxicity. The casesof missing target 3% (3 cases).
Conclusions: According the letterature this treatment schedule is effective
and can be used in skin cancers with a good compliance of the treated pts.
(seven days of treatment). HDR brachytherapy is a tecnique with a goodlearning curve that offers personalized treatments without radiation damage
to OAR ( as eye ) in alternative to conventional radiotherapy. Actually thisschedule is the standard for skin cancer in our Center.
949 poster

1

P ETER M AC C ALLUM C ANCER C ENTRE, Radiation Oncology, Melbourne,
Australia
2
P ETER M AC C ALLUM C ANCER C ENTRE, Medical Student, Melbourne,
Australia
3
P ETER M AC C ALLUM C ANCER C ENTRE, Biostatistics and Clinical Trials,
Melbourne, Australia

that was given in a dose of 60 Gy/30 fractions/6 weeks, 30 patients having
post radiation residual lesion not more than 6 cm in maximum dimension weretreated in this prospective non-randomized trial: 16 patients in the experimental arm and 14 in the control arm. Patients in the experimental arm received
brachytherapy boost dose of 24-25Gy/5-6 fractions on daily basis using highdose rate Ir192 source.
Results: Median follow-up was one year (range, 0.4:7.5 years). Median overall survival was 14 and 11 months for boost and control arms respectively (P= 0.49). Median progression free survival was 10 and 8 months for boost andcontrol arms respectively (P = 0.44). Acute and late toxicities were low. Twopatients developed limited CSF leakage and sever pain was reported in one
patient.
Conclusions: Increasing the dose of radiation by additional HDR brachytherapy boost prolonged the median OAS and PFS by 3 and 2 months respectively but the number of patients was too small to reach statistical significance.
The implant was tolerable and toxicity due to an additional brachytherapy
boost was low and may be considered as a safe treatment option.

S 363

HIGH DOSE RATE BRACHYTHERAPY BOOST FOR RESIDUAL
MALIGNANT GLIOMA: CLINICAL RESULTS FROM SINGLE INSTITUTION
M. H. Elnaggar1 , H. El Bakry1 , A. Fakhr2 , A. Hassouna1 , M. El-Sayed1
1
E GYPTIAN N ATIONAL C ANCER I NSTITUTE , C AIRO U NIVERSITY, Radiation
Oncology Department, Cairo, Egypt
2
FACULTY OF M EDICINE , A IN S HAMS U NIVERSITY, Neurosurgery, Cairo,
Egypt

Purpose: Investigate the role of additional brachytherapy boost in malignant
glioma patients having residual lesion after conventional radiotherapy treatment.
Materials: After initial surgical intervention and external beam radiotherapy

Purpose: Key drivers which led us to introduce a cancer network wide
electronic chemotherapy prescribing system in 2007 were: improved patient
safety; ensuring best practice using peer agreed chemotherapy regimens;
accurate treatment data for trusts and commissioners for governance andaccounting. In 2008 the National Chemotherapy Advisory Group (NCAG)
recommended improvements in chemotherapy services - we worked with the
supplier to develop the electronic system to deliver these.
Materials: 6 hospital trusts in a cancer network (2.5M pop) agreed to use
a centrally managed web based chemotherapy prescribing system. 13 Tumour Site Groups updated the network chemotherapy regimens. 60 clinicians
agreed: to dose band common drugs +/-5% to reduce costs; not to cap surface area; standardised day case hydration schedules, antiemetic and support regimens. A universal patient identifier (NHS number) was agreed. Links
with trust patient administration and pathology systems were established. A
confidentiality agreement between trusts was drawn up. 474 standard regimens (including 11 chemo RT), 353 clinical trial and 100 support regimens
were uploaded into the system and validated by 2 pharmacists and site specific clinicians. Trust based super users trained 984 staff using locally produced User Guides. At a national user group meeting in 2009 we proposedsystem improvements required for NCAG compliance.
Results: The system is used for all adult chemotherapy treatments. Auditof the electronic recording of administration by nursing staff has seen a risefrom 47 to 85% over a 3 month period. Performance status (18%) and toxicity recording (36%) have been fed back to staff to encourage recording.
Triage nurses access the system for patients with side effects. We configured the system to prescribe chemotherapy and support drugs separately.
Changes to the support regimens can therefore be implemented. Eg 25%
saving (e115K) in GCSF costs was achieved by making one simple change
to switch the drug used. A pilot download of 42 data fields for the proposed
national chemotherapy dataset is the first national test of this process. These
include: Diagnosis, staging, treatment line, performance status, consultant,
toxicity, reason for discontinuing and modifying the drug doses. Close liaison with the supplier led to improvements in the set up of these items in a
recent version upgrade. Additional reports and notes templates have been
written including: Treatment plan for GP and patient, regimen specific toxicity
assessments, end of treatment summary, chemotherapy unit referral and assessment forms. Regimens have been configured and reports developed: toreport activity for commissioners using the HRG codes; audit report of deaths
within 30 days of treatment.
Conclusions: A cancer network led initiative to convert chemotherapy prescribing to an agreed web based electronic system has been successfully
implemented.
951 poster
INITIAL EVALUATION OF THE DEVICE FOR ADVANCED VERIFICATION OF IMRT DELIVERIES (DAVID) AS AN IN-VIVO DOSIMETER
D. Johnson1 , F. Coveney1 , S. Weston1 , V. Cosgrove1 , D. I. Thwaites1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom

Conclusions: This preliminary investigation shows that, given a square fieldsize and number of monitor units the DAVID response can be predicated.
More work will be done to further characterise the response of the DAVID
so that the DAVID response can be predicted for any field shape. This will
enable the DAVID to be used as an upstream in-vivo dosimeter for conformal,
modulated and arc therapy deliveries.
952 poster
INTEGRATED TREATMENT IN 301 BRAIN TUMOR PATIENTS(PTS) SUBMITTED TO “PARTIAL SURGERY”(PS) FROM BRESCIAUNIVERSITY.
M. Buglione1 , P. Borghetti1 , B. Shehi1 , B. Lazzari1 , L. Donadoni1 , L.
Triggiani1 , M. Maddalo1 , R. Cavagnini1 , S. Pedretti1 , F. Barbera1 , S.
Magrini1
1
S PEDALI C IVILI DI B RESCIA, Radiation Oncology, Brescia, Italy
Purpose: Standard treatment of high grade glioma is radical surgery, radiotherapy (RT) and chemotherapy (CHT). Extent of surgery (SUR) is an important prognostic factor. It is debatable the therapeutic approach for pts with
PS. We analyzed in retrospect the treatment modalities and their impact onoverall survival (OS) in pts who underwent PS.
Materials: 541 pts treated with RT for WHO G3 and G4 brain tumor werecollected and the 301 pts given PS were identified. We analyzed the distribution of those accrued respectively 1985-1995; 1996-2002 and 2003-2010,
according to the different clinical, pathologic, and therapeutic features and theprognostic weight of each variable. Uni-and multivariate analysis of OS andχ2 -test were applied as appropriate.
Results: 91 pts (30%) were aged < 50 y; 156 (52%) had KPS >70 and 209(70%) had Order score 1-2; 164 pts had RMN before SUR, mostly in the lastaccrual period (57%) (χ2 -test p=0.000).26%, 70%, 1% and 3% had respectively biopsy only, PS, no SUR at all and SUR with unknown extent. Most pts
had RT as unique treatment (73%), the remaining had different combinationsof adjuvant CHT and RT, mostly in the last period (75%) (χ2 -test p=0.000).
RT volume included the site of disease, with or without a boost, whole brain(WB) and WB+boost in 55%, 8% and 37% of the pts respectively; larger volumes were used mainly in the earlier accrual period (97%) (χ2 -test p=0.000).
Low hypo-fractionated dose was given to 59 pts (20%), an higher dose (44 70 Gy) in the remaining. Exclusive RT, "big" RT volumes and palliative doses
were used mostly in the group of pts with biopsy only (p=0.02, 0.009 and0.02 respectively). Among the 79 pts submitted to biopsy only age guided thetreatment choice: 60% and 7% of older pts (> 65 y) were treated respectively
with low hypo-fractionated doses and with CHT vs 14% and 36% of youngerS 364OTHERS

OTHERSpts (<50y). Median actuarial OS of the entire group is 296 days. At univariate analysis, age <50 y, good KPS, more extensive SUR, use of CHT andhigher RT doses (>44Gy) were related to better OS (p=0.000; 0.000; 0.03
and 0.000, respectively); significance of all these features apart from CHT
was confirmed in the biopsy only group, when the biopsy only (79 pts) andPS (210 pts) groups were separately analyzed. Multivariate analysis confirmed the prognostic role, for OS (in the entire series, and in the biopsy only
and PS groups) of younger age (p value between 0.005 and 0.05) and of
higher dose (p=0.000 - 0.004). In the PS group and in the entire group KPS> 70 was significantly related to better survival (p < / =0.001). Biopsy only
conditioned a worse prognosis in the entire group (p=0.01) when compared
to PS.
Conclusions: This analysis confirms the role of multimodal "aggressive"
treatment in young pts with good KPS also in pts without radical SUR, especially if submitted at least to PS. RT doses > 44 Gy should be used. It
is confirmed the role of palliative treatment in older pts submitted to biopsy
alone.
953 poster
INTRADURAL, EXTRAMEDULLARY SPINAL LESIONS. FIVE YEARS,SINGLE-INSTITUTION RADIOSURGERY EXPERIENCE.
M. Marchetti1 , I. Milanesi1 , L. C. Bianchi2 , A. Brgentin2 , A. Franzini1 , G.
Broggi1 , C. L. Solero1 , L. Fariselli3
1
F ONDAZIONE IRCCS I STITUTO N EUROLOGICO C B ESTA, Neurosurgery,
Milano, Italy
2
C ENTRO D IAGNOSTICO I TALIANO, Radiation Therapy, Milan, Italy
3
I ST. N AZIONALE N EUROLOGICO "C. B ESTA ", Milan, Italy
Purpose: At the state of art, surgery represents the first choice treatments
for spinal, intradural lesions. The more recent advance in radiosurgery technology made possible treatments also in proximity of radiosensitive structures
such as the spinal cord. In this study we report about our own radiosurgery
experience in treatment of benign intradural, extramedullary tumours of thespine.
Materials: In this study we analyzed the 32 benign intradural, extramedullarylesions with a minimum follow-up period of 12 months. Five cases were associated to fibromatosis type 1 or 2. The lesions included 19 meningiomas,
11 schwannomas, 1 neurofibroma and 1 paraganglioma. Treatments planning were always CT based (1.25 mm thickness). CT and MR images werefused to better define the target volume and the critical structures. Planning
Tumour Volume (PTV) was defined as the radiographic tumour volume withno margin. All patients were clinically and radiologically evaluated before andafter treatment (every 6 months during the first two years and thereafter once
per year).
Results: The mean follow up was 38 months (range 12-78, median 36
months). All patients well tolerated the procedures. The mean tumour volume
was 10,3 cc (range: 0,2-138 cc, median 2,3 cc). Twelve patients underwent asingle fraction treatment, the total dose to the target ranged from 10 to 15 Gy(average: 12.3 Gy) to the 70-80 %. All the others received a hypofractionatedradiotherapy treatment (4 to 6 fractions) with a prescribed dose ranging from
14 to 30 Gy (average 22 Gy). The maximum dose to the spinal cord ranged
from 9 to 26 Gy. Although these are only preliminary results, during all thefollow-up period, no lesion showed a radiological evidence of progression.
Neurological conditions were preserved or improved. No permanent sequelae were registered. A significantly and durable pain relief (where present)
was observed. Nevertheless the present study also underlined an improvement in the quality of life (QoL).
Conclusions: Spinal frameless stereotactic radiosurgery was found to beboth safe and effective for extra-axial, spinal lesions. Although surgical excision remains the primary treatment option for most intradural tumours, CyberKnife offers a true alternative therapeutic modality for such lesions, especially in case of recurrent and residual lesions or when surgery is contraindicated.
954 poster
IS THE TOTAL GAMMA INDEX PREDICTIVE OF THE ACTUAL DOSE
TO ORGANS IN IMRT PLANS?
A. Miranti1 , S. Bresciani1 , A. Maggio1 , M. Stasi1
1
IRCC-C ANDIOLO, Department of Medical Physics, Candiolo, Italy
Purpose: MapCheck2 and its dedicated software are widely used devices
for the verification of IMRT plans. The goal of this work was to evaluate thevariation of the Gamma Index (GI) inside organs, target and organs at risk,
and the GI of the entire plan.
Materials: For 15 prostate cancer patients, submitted to a 5-field-smartIMRT treatment, the measured dose for each beam was acquired by using
2D diodes array MapCheck2 (Sun Nuclear, Melbourne, FL) and compared tothe planned dose calculated with Eclipse Treatment Planning System (Varian,
Palo Alto, California, USA). The pre-treatment quality Assurance evaluation
was assessed using Gamma Index (Van Dyk method), with a 10% isodose
threshold (TH), a percentage Dose Difference (%DD) of 3% and a Distance-

to-Agreement (DTA) equal to 3 mm. Patients’ structures were imported on
MapCheck 5.2 software which evaluates the points within the structures andcalculate GI inside them. We evaluated the GI for the PTV of prostate, for the
rectum, the bladder and the bowel. The GI of the entire plan was obtained
weighting the GI on the number of evaluated points of each beam. The GIof each structures for each beam was weighted on the points fitted in the
structure, too.
Results: For the 15 patients GI of the entire plan ranged from 90.3% to99%, mean 92.8%. Average GI for the PTV was 76% ranging from 60.3%
to 98.5%, for the bladder was 90.7% ranging from 85.8% to 99.3%, for the
rectum was 90.6% ranging from 84.7% to 98.3% and for the bowel was 93.9%
ranging from 90.9% to 94.9%. The lowest GI corresponds to the structureswith the lowest number of points. The percentage difference between the
GI calculated for a single structure in the plan and the GI of the entire plan
ranged from 33.3% to 0.3%. GI of the PTV is, for all of the patients, below the
GI of the whole plan, while for all the other investigated structures it can bealso higher.
Conclusions: Gamma Index is a useful and effective tool to evaluate IMRT
Treatment Plans, but it could not be used as a stand-alone parameter sincein may not represent the actual GI of a single structure. It may be of interest
to study the impact of the GI variation on the outcome of the treatment bycorrelating measured data to estimated DVH and comparing estimated DVH
to planned ones.
955 poster
LATE OUTCOMES FOR BLADDER SPARING CONCOMITANTCHEMORADIATION FOR NONMETASTATIC MUSCLE INVASIVE
BLADDER CANCER
G. Kacso1 2 , Z. Fekete3 , N. Todor4 , O. Veresezan5 , C. Cebotaru6 , N.
Ghilezan2
1
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Brachytherapy
Department, Cluj-Napoca, Romania
2
I ULIU H ATIEGANU M EDICAL U NIVERSITY, Cluj, Romania, Cluj, Romania
3
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Radiotherapy,
Cluj-Napoca, Romania
4
O NCOLOGY I NSTITUTE "P ROF.D R .
I ON C HIRICUTA ", Biostatistics,
Cluj-Napoca, Romania
5
C ENTRE H ENRI B ECQUEREL, Radiotherapy, Rouen, France
6
O NCOLOGY I NSTITUTE "P ROF.D R . I ON C HIRICUTA ", Medical Oncology,
Cluj-Napoca, Romania
Purpose: Analysis of long term outcomes of bladder sparing curative concurrent chemoradiation (CRT) for muscle invasive transitional bladder carcinoma.
Materials: From 1991 to 2003, 60 consecutive patients were prospectively
treated with curative intent chemoradiation: 40-50 Gy/20- 25 fr/4- 5 weeks external beam radiotherapy (EBRT) to the pelvis, plus Cisplatin (CDDP) 20mg/m
2/day, D1-5/q21 for T2 or 100mg/m2 / day/q21 for T3-4a as bladder sparing approach. The inclusion criteria were: T2-T4a transitional cell bladdercarcinoma completely resected by maximal TUR or partial cystectomy, ageless than 80 years, natural life expectancy of at least 5 years, ECOG performance status less or equal to 2, good hematology, liver, heart and renal
status. Cystoscopy re-evaluation was done at the completion of these doses
to all patients, with biopsies of the tumor bed and any other suspicious areas. The complete responders were simply followed while radical cystectomy
was offered to all others. Patients unfit medically or those refusing radical
surgery received, without split, a 10-20 Gy standard fractionation to the bladder, concurrent with the third cycle of CDDP. Bladder mapping biopsies were
performed 6 weeks after chemoradiation and during follow up. Salvage cystectomy was proposed in case of residual disease, relapse or severe radiation
cystitis refractory to conservative therapy. Toxicity was assessed according
to CTC 3.0 criteria.
Results: Median age was 58 years [33- 78]. There were 41.6 % T2, 33.3%
T3 and 25 % T4a; high grade predominate (60% G3).With a median followup of 7.5 years, 10 years overall, specific and radical cystectomy free survival
were 38, 46 and 42% respectively. Local recurrence was recorded for 45 % ofcases, 20 % being however superficial (some of them probably new primarytumors) and still allowing bladder conservation. GU, GI and hematologicalacute G3-4 toxicity were 15%, 10% and 5 % respectively whereas the correspondent figures for late toxicity were 6.6 %, 5 % and 1.6%. Doses above
60 Gy and 3 full dose cycles of CDDP were associated with higher rates andseverity of acute and late toxicity. Hydronephrosis, partial response to CRT
and, interestingly, doses above 60 Gy were correlated with poorer long term
survival.
Conclusions: CRT is highly effective for muscle invasive bladder cancer, with
10 years survival of 42 % with bladder conservation, in our experience. This
makes CRT a very reasonable alternative to the radical cystectomy. Acuteand late toxicity are quite low if the total dose is kept between 50 to 60 Gy
with concurrent Platinum.

S 365

956 poster

958 poster

LINAC-STEREOTACTIC RADIOSURGERY (LSRS) IN THE MANAGEMENT OF TRIGEMINAL NEURALGIA : MEDIAN 6 YEAR FOLLOW-UP
IN 51 CASES
Y. Ho1 , R. Mark1 , R. Akins1 , M. Nair1
1
J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department ofRadiation Oncology, Lubbock, USA

LUTETIUM-177 DOTATATE THERAPY FOR NEUROENDOCRINETUMOURS – THE UCLH EXPERIENCE.
M. Hadaki1 , C. Walker1 , J. Bomanji2 , J. Gains1 , M. Gaze1
1U NIVERSITY C OLLEGE L ONDON H OSPITALS NHS F OUNDATION T RUST,
Department of Radiation Oncology, London, United Kingdom
2
U NIVERSITY C OLLEGE L ONDON H OSPITALS NHS F OUNDATION T RUST,
Department of Nuclear Medicine, London, United Kingdom

Purpose: Stereotactic Radiosurgery (SRS) with the Gamma Knife (GK) has
been used successfully in the treatment of Trigeminal Neuralgia (TN). Results
have been comparable to open surgery. There have been few reports withthe use LSRS in the management of TN. We report our updated results with
LSRS in the treatment of TN.
Materials: Between 2000 and 2010, 51 patients with medically refractory
TN were treated with LSRS. Prior neurosurgical intervention had been performed in 39 patients. Twenty two patients had one procedure, 14 patients
two, and 5 patients three interventions. All patients had typical TN. LSRS wasgiven to the cranial nerve V entry root zone into the brainstem. Targeting was
defined by CT and MRI Scans, and CT Cisternogram, utilizing axial and coronal images. Treatment planning was accomplished thru Radionics Treatment
Planning System. The dose was 87 Gy to Dm, in one fraction using the 5 mm
collimator and 6 arcs with the 20% Isodose line just touching the brainstem.
This dosimetry is similar to Gamma Knife. The dose rate was 400 MU/min.
Average Arc length was 130 degrees. Response to treatment was defined as
excellent (no pain, off analgesics), good (no pain, with analgesics), and poor
(continued pain despite analgesics).
Results: With a median follow-up of 74 months (range 54-130 months),
62.7% (32/51) of patients have reported an excellent or good result after
LSRS. One patient has sustained permanent ipsilateral facial numbness. A
2nd patient developed anesthesia dolorosa.
Conclusions: LSRS offers comparable results to Gamma Knife SRS in the
management of TN.
957 poster
LONG TERM RESULTS FOR COMBINED MODALITY TREATMENT
FOR ANAL CANCER
I. Oblak1 , P. Petric1 , A. L. Vodusek1 , V. Velenik1 , F. Anderluh1 , R. Hudej2 ,B. Segedin1 , A. P. Fras1
1
I NSTITUTE OF O NCOLOGY L JUBLJANA, Radiation Oncology, Ljubljana,
Slovenia
2
I NSTITUTE OF O NCOLOGY L JUBLJANA, Radiotherapy and Brachytherapy
Planning Department , Ljubljana, Slovenia
Purpose: To analyse results of radiochemotherapy in patients with squamouscell carcinoma of the anal canal, treated at our institution.
Materials: Between January 2003 and January 2010, 80 (46 female,
34 male) patients with anal canal cancer were treated with radical radiochemotherapy at the Institute of Oncology Ljubljana. Planned treatment
schedule consisted of 3D conformal external beam radiotherapy (45 Gy in 25
fractions), with two cycles of concurrent chemotherapy (5-fluorouracil / mytomycin C), followed by interstitial brachytherapy or external beam boost (9 28 Gy) to the primary tumour. Actuarial rates of locoregional control (LRC),
disease-free survival (DFS), disease-specific survival (DSS), overall survival(OS), colostomy-free survival (CFS) and the rates of acute and chronic sideeffects were estimated. The impact of individual tumour- and therapy-related
factors on treatment outcome was assessed.
Results: Sixty-six (82.5 %) patients completed treatment according to theprotocol. The median follow-up time in 59 (73.8 %) survivors was 39 months(range 11-92 months). At 5-years LRC, DFS, DSS, OS and CFS rates were70%, 66%, 81%, 72% and 85% respectively. On multivariate analysis, complete disease response was identified as an independent prognostic factor
for LRC and all analysed survival rates (p<0,0001). Low Hb retained its independent prognostic value for OS (p=0.027), and salvage surgery for LRC(p=0.034) and DFS (0.039). The most frequent acute side-effect of treatment
was radiodermatitis (grade 3 in 58.8% of patients). Grade 3-4 late radiationside effects according to the LENT-SOMA scoring system were observed in
13 (16.3%) patients. Late anal stenosis, chronic ulceration and grade 3 4 incontinence developed in 3 (3.8 %), 2 (2.5 %) and 7 (8.8%) of colostomy-freesurvivors, respectively. Patients treated with brachytherapy boost on primarytumor had less late site effects compared to patients treated with externalbeam boost. The difference was statistically non-significant (p=0.058).
Conclusions: Radiotherapy with concurrent 5-FU / Mitomycin C chemotherapy is feasible, with acceptable toxicity. The presented treatment outcome iscomparable to other published results.

Purpose: Peptide receptor radionuclide therapy is a treatment option for patients with metastatic neuroendocrine tumours. Lutetium-177 DOTATATE is
one of several possible radionuclide-vector combinations. Lutetium-177 allows better imaging of uptake than Yttrium-90 and DOTATATE may spare kidneys more than DOTATOC. The aim of study is to audit our experience oflutetium DOTATATE therapy for metastatic neuroendocrine tumours.
Materials: Patients with adult type neuroendocrine cancers shown on
Gallium-68 DOTATATE PET/CT to have SUV greater in tumour than liver were
eligible for therapy. Patients received premedication with anti-emetics and an
amino acid solution to protect renal function. A standard activity of 7.4GBq
was then administered by IV infusion. Objective response was determined
by Gallium-68 DOTATATE PET/CT; subjective response by symptom assessment. RTOG toxicity scoring and overall survival was also measured.
Results: Since 2007 we have treated 21 patients: 11 males and 10 females;
median age 55 years (range 15-74). They received between 1 and 4 administrations, totalling 50. Of the 21 patients, 5 are still undergoing treatment
and are not evaluable. Of 16 evaluable, 6 did not complete treatment due
to disease progression. On re-assessment imaging, 7 patients had SD; 2
patients had a PR and 1 a CR. Clinical assessment at follow up shows that
10 patients had a good clinical response to therapy with 9 reporting improved
symptom control (5 of these becoming completely asymptomatic). Symptoms
occurring within 24 hours of the 50 administrations included nausea (10), abdominal discomfort or pain (7), diarrhoea (6), vomiting (5) and fatigue (3) andflushing (2). These may have been acute side effects or symptoms of the disease. Sub-acute haematological toxicities reported include grade 1 anaemia(15); grade 2-3 thrombocytopenia (10); grade 1-3 leukopenia (10) and grade
3 neutropenia (5). Myelosuppression resolved with appropriate support. No
serious delayed toxicities were reported.
Conclusions: Our audit showed that Lutetium-177 DOTATATE therapy is asafe and well tolerated treatment for patients with metastatic neuroendocrine
tumours. Among those who completed the treatment the clinical and radiological response rate were 90% and 30% respectively.
959 poster
MINIMISING VARIABILITY IN NECK FLEXION AND LAT HEAD
ROTATION FOR PATIENTS IMMOBILISED IN MASKS.
J. Palmer1
1
OXFORD C ANCER C ENTRE , C HURCHILL H OSPITAL, Radiotherapy, Oxford,
United Kingdom
Purpose: To minimise rotation and flexion within a mask and ensure correct
fit throughout the patient’s treatment.
Materials: Having recognised that radiographers can fit a mask with up to
a 10mm variation in the sup/inf direction. 50 patients with masks had a set
position in the sup/inf direction on the head rest before the mask was madewhich was checked and replicated on CT but no measurement given to thetreatment machine. The next 50 patients had a set measurement at mouldroom that was replicated on the CT and also set on the treatment machine.
The images taken routinely for both sets of patients were reviewed, looking
specifically for lateral pitch to show flexion of neck and rotation of the skull.
Results: There was less flexion and rotation in the group that the treatmentarea set the patient in the correct sup/inf direction on the head rest before
applying the mask. The masks were reported to be easier and quicker to fit
by the treatment radiographers.
Conclusions: Patient position within the mask is variable in the sup/inf direction (even with a customised head rest); this will affect the amount of flexion
and rotation of the patient. Ensuring that the patient is in the same position on
the head rest in the sup/inf direction before the mask is applied will minimise
this.
960 poster
MULTI-SESSION RADIOSURGERY FOR VESTIBULAR SCHWANNOMAS. LOCAL CONTROL AND HEARING PRESERVATION.
M. Marchetti1 , I. Milanesi1 , L. C. Bianchi2 , A. Bergantin2 , G. Broggi1 , L.
Fariselli1
1
F ONDAZIONE IRCCS I STITUTO N EUROLOGICO C B ESTA, Milano, Italy
2
C ENTRO D IAGNOSTICO I TALIANO, Milan, Italy
Purpose: Aim of the present study is to evaluate the possible advantage ofmultisession radiosurgery both in terms of effectiveness and safety.

S 366OTHERS

OTHERS

Materials: All the 61 patients included in present study underwent a multisession radiosurgery treatment with a prescription dose of 18 Gy, in 3
fractions All patients are classified according to the American Academy of
Otorinolaryngology-Head and Neck Surgery classification. In order to improve the target definition and to obtain more anatomic details about the critical structures the CT images were always fused with MRI. Cranial nerve function, audiograms, and magnetic resonance images (MRI) were monitored 2
months after treatment and every 6 months thereafter. The PTV was definedas the tumour volume without margin. The mean tumour volume was 4,5
cc (range 0,05-13,2cc; median 3,6cc). The mean dose to the cochlea was
16,3Gy to the 50% of the volume.
Results: the mean f follow-up period was 35 months (range 23-60 months).
Four patients died during the follow-up. One patient had a cerebral stroke
and other three patients died due to unrelated causes. The tumour growth
control was achieved in 95% of the series. Eighteen percent had a partial response (shrinkage > 25%). Only the 5% of the patients showed a progression
disease. The 75 % of the patients maintained a serviceable hearing function.
Conclusions: Although the short follow-up period, the preliminary resultsfrom this experience suggests that multisession radiosurgery by CyberKnife
would be safe and effective. The tumour growth control was optimal and thehearing function preservation rate was promising.
961 poster
OUR EXPERIENCE WITH ADJUVANT RADIOTHERAPY IN PATIENTSWITH CUTANEOUS MALIGNANT MELANOMA
A. Masarykova1 , D. Scepanovic1 , M. Pobijakova1 , M. Havrankova2
1
N ATIONAL C ANCER I NSTITUTE OF S LOVAKIA, Department of Radiation
Oncology, Bratislava, Slovakia
2
N ATIONAL C ANCER I NSTITUTE OF S LOVAKIA, Department of Dermatology,
Bratislava, Slovakia

Purpose: Background: The primary treatment of a cutaneous malignant
melanoma is surgical excision. Radiation therapy is not part of the traditional
adjuvant treatment approach due to historically fact that melanoma has been
considered as a relatively radio-resistant tumour. The aim of this study is totry to assess the value of radiotherapy as adjuvant form of treatment.
Materials: The medical records of 33 patients (pts) with malignant melanoma
were retrospectively reviewed. They are treated during the period from 2005
till 2009. Median age was 64 years (yrs) (min=32, max=84). There were 14
female and 19 male pts. All pts were initially treated with surgical excision.
Forty eight per cent of pts performed adjuvant therapy while 52% of pts did
not. Six pts received adjuvant systemic therapy. However, adjuvant radiotherapy (ART) was performed in 10 (30%) pts but 23 (70%) pts were without ART.
Adjuvant radiotherapy was applied on the primary tumor (1 patient) and regional lymph nodes (9 pts) to a median dose of 48Gy at 4Gy/fraction delivered
three times weekly.
Results: At a median follow-up of 36 months, 31 pts had relapsed and 20 pts
had died. The median time to progression (TTP) was 13 months for all pts.
In the group of pts with ART loco-regional relapse is diagnosed in 1 patient
while 6 pts had loco-regional relapse in group of pts without ART. There wereno statistically significant difference in loco-regional relapse rate between two
groups of pts (p=0.3968, Fisher’s test). Seven pts developed distant metastases in ART group and 17 pts in group without ART. There were no statistically significant difference in distant relapse rate between two groups of pts(p=1, Fisher’s test). However, two pts were without relapse in ART group ofpts (p=0.0852). In whole group of pts the actuarial overall and disease-freesurvival rates at 3 yrs were 58% and 10%, respectively. There were no statistically significant difference regarding 3-year overall survival (OS) between
ART and without ART groups of pts (76%, 67% respectively, p=0.13). However, there was statistically significant difference regarding 3-year disease
free survival (DFS) favoring ART group of pts (70% versus 46%, p=0.008).
Conclusions: Although ART did not improve OS in our pts, use of ART
demonstrated superior 3-year DFS compared with group of pts without ART.
Consequently, there may be an opportunity to integrate adjuvant radiotherapy
into the multimodality treatment of pts with malignant melanoma.
962 poster
OUTCOMES OF THREE-DIMENSIONAL CONFORMAL RADIOTHERAPY FOR RESIDUAL, RECURRENT, OR UNTREATEDMENINGIOMAS
S. M. Yoon1 , Y. Jeong1 , J. H. Park1 , S. S. Kim1 , Y. S. Kim1 , S. Y. Song1 , S.
W. Lee1 , J. H. Kim1 , E. K. Choi1 , S. D. Ahn1
1
A SAN M EDICAL C ENTER, Radiation Oncology, Seoul, Korea Republic ofPurpose: To evaluate of long-term outcome of residual, recurrent, or untreated meningiomas treated with three-dimensional conformal radiotherapy(3D-CRT).
Materials: From January 1990 to June 2007, forty-four patients were treatedwith definitive (n=13) or postoperative radiotherapy after gross total or subtotal resection (n=31). Of the patients, 15 (34.1%) were men and 29 (65.9%)
were women. Patient ages ranged from 22 to 75 years with a median of 48

years. The median tumor size was 3.6 cm (range, 1.6 6.2 cm). The median total dose was 54 Gy (range, 50 60 Gy) with daily fraction size of 1.8
2 Gy. Tumor control was evaluated clinically and radiologically by magnetic
resonance imaging or by computed tomography.
Results: The median follow-up was 64.8 months (range, 39.2 126.3 months).
Of these, 42 were locally controlled. One failure occurred 12 months after
3D-CRT and a second at 6 years after 3D-CRT. Five-year local relapse-freesurvival rates were 94.1%. The 5- and 10-year overall survival rates were
91.9% and 72.6%, respectively. Acute toxicities during radiotherapy weremild and transient. Late morbidity was observed in 3 patients during longterm follow-up.
Conclusions: 3D-CRT affords satisfactory long-term local control without
significant treatment-related morbidity. Radiotherapy can be an alternative
treatment for meningiomas especially in situations, not suitable for surgery.
963 poster
PATTERNS OF CARE AND OUTCOMES OF ADULT OSTEOSARCOMA IN A TERTIARY CARE CANCER CENTRE IN PAKISTAN
A. S. Kazmi1 , S. Imtiaz1 , G. Husnain2 , S. Iqbal1
1
S HAUKAT K HANUM M EMORIAL C ANCER H OSPITAL & R ESEARCH C ENTRE,
Department of Medical Oncology, Lahore, Pakistan
2
S HAUKAT K HANUM M EMORIAL C ANCER H OSPITAL & R ESEARCH C ENTRE,
Department of Internal Medicine, Lahore, Pakistan
Purpose: Osteosarcoma is a relatively uncommon tumour in adults and treatment protocols are evolving. We present our experience of treatment outcomes in adult osteosarcoma patients.
Materials: 188 adult osteosarcoma patients were identified from 1995 till
August 2009. Of these only 74 patients completed the planned treatment,
while the rest defaulted. These 74 patients are included in this retrospective
analysis. Median duration of follow-up was 1.94 years. 58 (78%) patientswere in the age group of 18-29 years. Male-female ratio was 3:1. Commonest site of disease was femur(43%) followed by tibia(37%). 63 (85%)
had localized disease(LD) at presentation. Commonest site of metastasis atpresentation was lungs(7/11). 14/63 patients (34%) with LD and 4/7 (57%)
with lung only metastases underwent primary definitive surgery(PDS) while
49 (66%) with LD and 2/7(28%) with lung metastases received neoadjuvant chemotherapy(NAC) which was Cisplatin/Doxorubicin based. High-dose
Methotrexate(HDMTX) was part of chemotherapy in 20/51(39%) patients. In
all 66 patients underwent definitive surgery(PDS=18, NAC =48). 61 patients
received adjuvant chemotherapy(AC). This consisted of Cisplatin/Doxorubicinin 28(46%), Cisplatin/Doxorubicin/HDMTX in 24(39%) and Ifosfamide based
regimen in 9(15%) patients.
Results: Of the 66 patients undergoing definitive surgery, 59 (89%) had amputation. All of the limb salvage operations(7/61) were in the NAC group.
Good histopathological response(>90% tumor necrosis) rate in HDMTX containing regimens was 7/20(35%) and non-HDMTX regimens was 11/31(35%)
with an overall good response rate of 35%(18/51). Thirty-four patients arealive to date(28 without and 6 with disease). The commonest site of relapse
was lung(41%). Twelve out of 21 patients with lung only metastases underwent successful metastatectomy. Overall survival(OS) for all 74 patients at 2
years was 71%. For patients with LD at presentation median EFS was 1 year
and median OS 2.4 years with 2-year EFS 42%, and 2-year OS 82%. For
patients with metastases at presentation median PFS was 0.66 year, medianOS 1.47 years and 2-year OS 45%. Median OS for patients receiving HDMTX
containing vs non-HDMTX regimens was 1.7 years vs 2.9 years.
Conclusions: Adult osteosarcoma treated with Cisplatin/Doxorubicin based
chemotherapy and surgery has good outcomes. The role of HDMTX in adultosteosarcoma remains uncertain. In our experience a vast majority of patients declined treatment due to fear of limb amputation.
964 poster
PATTERNS OF RECURRENCE AND SURVIVAL IN 168 GLIOBLASTOMA PATIENTS AFTER TEMOZOLOMIDE BASED CHEMORADIATION
I. Coremans1 , R. Wiggenraad2 , M. Jong de1 , J. van Santvoort2 , D. ages1 ,H. Putter3 , S. van Duinen4 , R. Natte4 , M. Taphoorn5 , C. Marijnen1 , C.
Creutzberg1
1
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Department of ClinicalOncology, Leiden, Netherlands
2
R ADIOTHERAPY C ENTRE W EST, The Hague, Netherlands
3
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Department of Medical
statistics, Leiden, Netherlands
4
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Department of Pathology,
Leiden, Netherlands
5
M EDICAL C ENTER H AAGLANDEN, The Hague, Netherlands
Purpose: To investigate the patterns of recurrence and survival and prognostic factors in a consecutive series of 168 patients with newly diagnosed
glioblastoma treated with temozolomide (TMZ) based chemoradiation.
Materials: From July 2004 to July 2009, 168 patients with glioblastoma weretreated after surgical resection or biopsy in two radiotherapy centres (60 Gy to
the tumor with 2 cm margin, 3D conformal planning), with TMZ concomitant(75 mg/m/d) and adjuvant (6 cycli of 5 days; 150 mg/m/d). Clinical, pathological, MGMT methylation and treatment data were collected and reviewed. For
analysis of the patterns of failure, the pretreatment and serial post treatment
MRI scans were registered with the original CT planning scans. The exact
localization of the recurrences was determined as in-field (central i.e. local
progression), marginal, or out-of-field, defined with respect to the 95% isodose (D95) of the original treatment plan of the primary tumor. Recurrenceswere regarded out-of-field in case of ≤20% overlap with the D95; in-field incase of >80% overlap, and marginal if >20% and ≤80% overlap. Follow-up
was complete for all 168 patients. Analysis was done using the logrank test,
Kaplan-Meier method, Cox proportional hazards model and Chi square test.
Results: Median follow-up of for patients alive was 13.2 months. The median
OS was 14 months (95% C.I. 12.3-15.8 months), with 1-year and 2-year survival rates of 62% and 33%, respectively. The overall median PFS was 8.5
months (95% C.I. 7.7-9.4 months): 18.4 months for MGMT methylated patients in contrast to 7.6 months for those with unmethylated MGMT (p=.010).
Recurrences were diagnosed in 132 of 168 patients. Among these recurrences, 82% were in-field, 11% marginal and 7% out-of-field. Although arelationship was found between the time to recurrence and MGMT methylation status, there was no relation between MGMT status and pattern of recurrence. Prognostic factors for survival were age, type of surgery, MGMT
status, location of the primary tumour (solitary/multiple) and WHO. In multivariate analysis age, WHO, MGMT status and type of surgery remained
significant prognostic factors.
Conclusions: Although survival has improved after introduction of TMZ
based chemoradiation, central recurrence still predominates. Patients withmethylated MGMT had a significantly better OS and PFS. MGMT methylation
status was not related with the pattern of recurrence.
965 poster
PILOT STUDY OF ADJUVANT FRAMELESS STEREOTACTIC RADIOTHERAPY (FSR) TO THE SURGICAL CAVITY IN PATIENTS WITH
BRAIN METASTASES.
S. Villà Freixa12 , C. Hostalot1 , D. Linero1 , L. Escude1 , S. Canales1 , R.
Arnalte1 , E. Vargas1 , I. Toscas1 , S. Jorcano Picart1 , R. Miralbell31
1
I NSTITUTO O NCOLOGICO T EKNON, Barcelona, Spain
2
C ATALAN I NSTITUTE OF O NCOLOGY. B ADALONA, Radiation Oncology,
Badalona. Barcelona, Spain
3
H ÔPITAL C ANTONAL U NIV. G ENÈVE, Geneva 14, Switzerland
Purpose: To assess the feasibility of adjuvant FSR in patients with brain
metastases (BM) after complete resection.
Materials: The first 11 patients (6 male and 5 female) treated since 2009 at
Instituto Oncolo Teknon are presented. The median age was 57 years (range,
44-77). The primary tumour origin was the lung in 7 cases, the breast in 2, thekidney in 1, and unknown in 1. The median KP score was 80% (range, 70100). Four patients were RPA class I and 7 class II. The GPA score was 1.5 in
3 patients, 2.0 in 3, 2.5 in 3, and 3.0 in 2. Depending on size and/or locationof the original BM, 8 patients received a single treatment session while 3 weretreated with a hypofractionated schedule.The median PTV was 6.9 cc (range,
1.1-32.7). The median single fraction and hypofractionation total dose was
17 Gy (range, 16.1-19.1) and 18 Gy (range,15-24), respectively.
Results: The median follow-up was 12 months (range, 3-23). One case ofradiation necrosis was observed (20 months after FSR). Whole brain radiotherapy was delivered, in addition, to 3 patients (1 patient before FSR and 2
patients after progression 4 and 8 months after FSR). Four more patients progressed after FSR and were successfully re-treated with FSR. One of thesepatients progressed systemically.
Conclusions: Adjuvant FSR after BM excision is feasible and may avoid
whole brain radiotherapy in a significant number of patients.
966 poster
PLASTIC-WATER PHANTOMS IN CLINICAL PROTON DOSIMETRY
L. AL-Sulaiti1 , D. Shipley2 , R. Thomas2 , P. Owen2 , A. Kacperek3 , P.
Regan1 , H. Palmans2
1
U NIVERSITY OF S URREY, Department of Physics, Guildford, United
Kingdom
2
N ATIONAL P HYSICAL L ABORATORY, Radiation Dosimetry Team, Teddington, United Kingdom
3
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Douglas Cyclotron, Bebington,
Merseyside, United Kingdom
Purpose: Plastic-water phantoms are widely used in radiotherapy as a substitute for water, in particular for non-reference dosimetry. However, they areusually made water equivalent for a particular beam type and not universallywater equivalent due to their different elemental composition than water. Numerous studies of the water equivalence of plastic-water phantoms have beenreported for photon and electron beams, but none in clinical proton beams. In
the latter, non-elastic nuclear interactions take place which could potentially

S 367

influence the water equivalence.
Materials: In this work, the water equivalence of plastic water (PW), plastic
water diagnostic therapy (PWDT) and WT1 phantoms was studied for proton energies of 60 MeV and 200 MeV. The fluence correction factor at waterequivalent depths was calculated; first with respect to water and then withrespect to graphite. This was performed by analytical model calculations,Monte Carlo (MC) simulations using MCPNX 2.5.0 and FLUKA 2008.3 andexperiments in the Clatterbridge Centre for Oncology (CCO) 60 MeV clinicalproton beams.
Results: Analytical calculations showed primary proton losses of 5% and
25% for all materials in 60 MeV and 200 MeV protons, respectively. The derived fluence corrections with respect to water are smaller than 0.5% for 60
MeV proton beams for all three plastics while for 200 MeV they are up to 1%
for PW and WT1 and up to 2% for PWDT. MC simulations showed that the
fluence correction factor with respect to water was up to 0.3% different fromunity for PWDT and WT1 and unity for PW at 60 MeV. At the higher energy
of 200 MeV, the correction was less than 0.4 % for PW and less than 1% for
PWDT and WT1 up to the entire penetration depth. The experimental results
for modulated and un-modulated 60 MeV proton beams showed good agreement with the MC simulation yielding small fluence corrections with respect
to graphite of less than 1 % for the three plastic-water phantoms. Graphite
has previously been shown to exhibit good water-equivalence.
Conclusions: All three plastic-water phantom materials showed good waterequivalence for dosimetry in clinical proton beams.
967 poster
PROGNOSIS OF T4 ESOPAGEAL CARCINOMA WITH THREEDIMENSIONAL CONFORMAL RADIOTHERAPY (3D-CRT)
Y. Wang1 , S. Zhu1 , J. Wang1 , R. Qiu1 , J. Su1 , W. Shen1
1
T HE F OURTH H OSPITAL OF H EBEI M EDICAL U NIVERSITY, Radiation
Oncology, Shijiazhuang, China
Purpose: To explore prognosis and its related factor in T4 esopageal carcinoma with three-dimensional conformal radiotherapy (3D-CRT).
Materials: From January 2001 to June 2007, 130 patients of esopageal cancer were treated with 3D-CRT, total dose of irradiation was 50Gy-76Gy. Gender, age, location of primary tumor, the different bite, the lesion length inbarium esophagogram, the largest diameter of lesion in CT scaning image,
metastasis of lymph node, M stage, dose of irradiation, chemotherapy andrecent efficacy were used as analysis factor for COX regerssion univariate
and miltivariate analysis.
Results: After radiotherapy, CR in 34, PR in 83 and NR in 13 patients, therate of total efficiency(CR+PR) was 90%. 1-,3-,4-years survival rates andmedian was 7.69%, 22.73%, 6.92% and 14.2months respectively. With univariate analysis, location of primary tumor, the different bite, the lesion length
in barium esophagogram, the largest diameter of lesion in CT scaning image,
metastasis of lymph node or organ, and recent efficacy were related withprognosis of esophaeal cancer after 3D-CRT (p0.05); but gender, age, doseof irradiation and chemotherapy were not related with prognosis of esophaealcancer(p0.05). With miltivariate analysis, location of primary tumor, the different diet, the lesion length in barium esophagogram, metastasis of lymph
node and M stage were independent prognostic factor.
Conclusions: For patients of T4 stage esophageal cancer with 3D-CRT, themain prognotic factor were location of primary tumor, the different diet, the lesion length in barium esophagogram, metastasis of lymph node and M stage.
968 poster
RADIATION THERAPY IN THE MANAGEMENT OF RENAL CELLCARCINOMA
R. Sharma1 , R. Sharma2 , R. Bargotra3 , . Dinesh Kumar4 , A. Gupta5
1
G OVERNMENT M EDICAL C OLLEGE J AMMU, Dept. of Radiation Oncology
and Radiation Therapy, Jammu, India
2
G OVERNMENT M EDICAL C OLLEGE J AMMU, Department of Radiological
Sciences, Jammu, India
3
G OVERNMENT M EDICAL C OLLEGE J AMMU, Departments of Pathology,
Jammu, India
4
G OVERNMENT M EDICAL C OLLEGE J AMMU, Department of Preventive
Medicine, Jammu, India
5
G OVERNMENT M EDICAL C OLLEGE J AMMU, Department of Radiation
Oncology and Radiation Therapy, Jammu, India
Purpose: Role of radiation therapy (RT) in the treatment of renal cell carcinoma has been controversial except for focal palliation of metastases. Retrospective data suggests possible utility of adjuvant and pre-operative radiation
therapy. We performed a retrospective review of patients with renal cell carcinoma treated in our department with the aim of finding out how our resultscompare with the medical literature regarding stage distribution, local control and survival by stage, and outcome after adjuvant and palliative radiation
therapy.
Materials: A total of 41 patients of renal cell carcinoma were treated between
January, 2001 and December, 2009 and were included in the analysis. Diag-S 368OTHERS

OTHERS

nosis was confirmed using CT scan, MRI, USG, Angiography and FNAC. 12
patients received palliative RT to bones, brain and unresectable large primarytumor. 10 patients received adjuvant RT after radical nephrectomy. Dose of
RT was 4500 cGy in 25 fractions over 5 weeks.
Results: The patients included 31 males and 10 females with a median age
at presentation of 55 years (range 20 91 years). All patients had histologicalproved RCC including 37 patients with clear cell carcinoma, 3 patients withpapillary renal cell carcinoma and 1 patient with oncocytoma. There were
3 patients with Grade 1, 14 patients with Grade 2, 20 patients with Grade
3 and 4 with Grade 4 histology. 9 (22%) patients had distant metastasis atpresentation. There were 9 patients with T1, 5 patients with T2, 20 patientswith T3 and 7 patients with T4 disease. 20 patients had tumor in right kidneyand 21 patients had it in left kidney. The median maximum diameter of thetumor was 8 cm (range, 4 20 cms). 22 out of 41 patients received RT at somepoint of time in their life. The median follow up for patients was 19 months(range 4 52 months). Mean locoregional relapse free survival was 15.46
months. Mean distant relapse free survival was 18.29 months. Mean relapse
free survival for stage I and II was 30.64 months, and for stage III and IV was
11.88 months. Mean overall survival of 9 patients with distant metastasis atpresentation was 4 months. Median locoregional relapse free survival for 10
patients who received adjuvant radiation therapy was 15 months versus 12
months for those who did not receive adjuvant radiation therapy.
Conclusions: Radiotherapy is an effective treatment modality in the management of renal cell carcinoma though it has not been shown to significantly
improve locoregional relapse free survival in the adjuvant setting.
969 poster
RADIOSURGERY (SRS) FOR ACOUSTIC NEUROMAS - WHAT
HAPPENS LONG TERM?
D. Roos1
1
R OYAL A DELAIDE H OSPITAL, Radiation Oncology, Adelaide, Australia
Purpose: Long term follow-up data on SRS for acoustic neuromas is limited.
This report summarises the results of the Royal Adelaide Hospital experiencefor patients treated with linac SRS at least 10 years ago.
Materials: Data was collected prospectively in the SRS clinic for 51 patientstreated between 1994 and 2000. Four patients with NF2 and three treatedfor post-operative recurrence were excluded. For the remaining 44 patients,
the median age was 63 (range 33-75), 26 were male and the median tumour
diameter was 21 mm (range 11-34 mm). The marginal dose was 14 Gy (4patients) or 12 Gy (40 patients).
Results: No patient required surgical salvage. For the 35 patients with atleast 10 years of potential follow-up (eight died and three were lost to followup before 10 years), 5 tumours remained stable and 30 decreased in size
(median shrinkage 5 mm, range 3-15 mm). Of 22 surviving patients withserviceable hearing at presentation (pure tone average ≤ 50 dB), 5 patients(23%) have retained serviceable hearing at 107-183 mo follow-up, while 17
patients (77%) lost it at a median of 25 mo (range 8-77 mo). Five patients
had new or worsened trigeminal neuropathies (14 Gy = 2, 12 Gy = 3), one ofwhom also had a facial neuropathy (12 Gy), all transient. Three patients required ventriculo-peritoneal shunting at 5, 6 and 27 mo (two with pre-existing
ventriculomegaly). There were no second tumours attributable to the SRS.
Conclusions: Long term follow-up of SRS for acoustic neuromas confirms
excellent tumour control (100% freedom from surgical salvage), but few patients preserve useful hearing. Late morbidity is very rare.
970 poster
RADIOTHERAPY +/- TEMOZOLOMIDE IN ELDERLY PATIENTS WITHGLIOBLASTOMA
M. Niyazi1 , S. Schwarz1 , B. Suchorska2 , F. W. Kreth2 , J. C. Tonn2 , C.
1

Belka
1
L.-M AXIMILIANS -U NIV., K L .
G ROSSHADERN, Radiation Oncology,
München, Germany
2
L.-M AXIMILIANS -U NIV., K L . G ROSSHADERN, Neurosurgery, München,
Germany
Purpose: The optimal treatment for elderly patients (age ≥ 70 years) withglioblastoma (GBM) remains controversial. We conducted a retrospective
analysis in 43 consecutive elderly patients with glioblastoma who either underwent radiotherapy (RT) or radiotherapy plus concomitant temozolomide(TMZ).
Materials: 43 patients 70 years of age or older (median age 75.8 years) witha newly diagnosed glioblastoma and a Karnofsky performance status (KPS)≥ 70 were treated with RT alone (median 60 Gy in 2 Gy single fractions) or
RT plus TMZ at the dose of 75 mg/m2 per day. The two groups were wellbalanced, univariate (log-rank test) and multivariate Cox proportional hazards
analysis were used to identify relevant prognostic factors.
Results: The median overall survival (mOS) of the entire patient cohort was
264 days (8.8 months) and the median PFS was 192 days (6.4 months). The
factors age, sex, previous surgery, KPS and the concomitant use of TMZ had
no significant influence on overall or progression-free survival (PFS) which

was confirmed by multivariate analysis. TMZ use resulted in a trend towards
poorer overall survival when applied concomitantly (314 days compared to
192 days within the TMZ group, p = 0.106). The subgroup analysis revealed
that TMZ use resulted in significantly worse survival rates in patients withKPS 70, for patients with KPS 80 this difference was not detectable.
Conclusions: TMZ should only be used carefully in elderly patients with unfavourable KPS. In this patient cohort, radiotherapy alone is a reasonableoption. Standard RT plus concomitant TMZ may be a treatment option only
for those elderly patients presenting with good prognostic factors.
971 poster
RADIOTHERAPY AND DISEASE-FREE SURVIVAL FOR PATIENTSWITH DESMOID TUMORS: A CASE REPORT AND REVIEW OF
LITERATURE
A. Parisi1 , S. Takanen1 , V. Graziano1 , B. Resuli1 , S. Fouraki1 , G. Parisi1 , R.
Lisi1 , N. Raffetto1
1
L A S APIENZA U NIVERSITY, Department of Radiation Oncology, Rome, Italy
Purpose: Extra-abdominal desmoid tumours or aggressive fibromatoses are
rare, slow-growing, benign lesions derived from fibroblastic cells, with variable biological behaviour. They account for about 0.03% of all neoplasms andless than 3% of all soft tissue tumours. Desmoid tumours are associated withhereditary syndromes, pregnancy, (especially if second) and female sex hormones in adults. The aggressive nature, the high recurrence rate and the tendency to infiltrate and invade critical structures of extra-abdominal desmoid
tumours require a multidisciplinary approach in the pathology’s management.
Radiation therapy showed to have an important role for increasing diseasefree survival and to reduce local tumour recurrence.
Materials: In 2002 a 23-year-old woman was admitted with a slowly-growing
mass of 2 years duration, located on the upper medial surface of the shoulder.
Physical examination revealed a firm, non movable and moderately painful
mass attached to the scapula but not adhering the overlyring skin. The patientunderwent local excision of the lesion and the histopathological examination
showed features of extra-abdominal periosteal fibromatosis with low mitotic
index and negative resection margins. Local lymph nodes were normal. In
2004 and 2007 the young woman had a local recurrence of the lesion treatedby surgical intervention with complete excision of the disease. After the last
surgery, she underwent an adjuvant hormone-therapy (tamoxifene 20 mg/die)and 3D Conformational External-Beam radiation therapy (EBRT) using a 6
MV photon linac directed to a target area at the left chest, for a total dose of
60 Gy, with 200 cGy daily fractions (5/w).
Results: Wide surgical excision represents the gold standard treatment ofthese tumours, even if they are characterised of a high local recurrence rate,
due to their infiltrative nature. Despite adequate margins, local recurrenceis a significant problem that has been reported to range from 25% to 77%
at en years. Few cases, showed by literature, evidence that EBRT improves
local control of desmoid tumours, in adjuvant setting, mainly in adults in unresectable disease and for gross residual tumour with positive or equivocal
surgical margins, also to avoid mutilating surgery. Our case report has confirmed the role of radiation therapy in increasing disease-free survival, without
suffering significant side effects: currently the patient is in good conditions
with a recurrence- free survival time of 3 years.
Conclusions: Adjuvant postoperative radiotherapy improves local tumour
control and could therefore reduce the recurrence rate, increasing diseasefree survival period in an aggressive malignant disease, such as desmoid
tumour. This study shows the impact of radiotherapy on 3 year-disease freesurvival. In conclusion, clinical trials can guide us choose to deliver RT immediately after surgery or wait till the relapse.
972 poster
RADIOTHERAPY WITH CONCOMITANT WEEKLY LOW DOSEGEMCITABINE FOR LOCALLY ADVANCED PANCREATIC CANCER
A. KAWAGUCHI1 , M. Yokokawa1 , S. Ikeda1 , M. Masahiro1 , Y. Kawabata2 ,S. Yano2 , T. Tanaka2 , N. Uchida1
1
S HIMANE U NIVERSITY FACULTY OF M EDICINE, Department of Radiation
Oncology, Izumo Shimane, Japan
2
S HIMANE U NIVERSITY FACULTY OF M EDICINE, Department of Surgery,Izumo Shimane, Japan
Purpose: To evaluate the feasibility and efficacy of radiotherapy concomitantwith weekly low dose Gemcitabine for locally advanced pancreatic cancer.
Materials: We reviewed 16 patients (male 5, female 11, ages 55 to 84 years,
median 71 years) with pancreatic cancer who received chemo-radiotherapy
from June 2008 to December 2009. The condition of six of the 16 patients
prevented surgical intervention due to invasion of major vessels. Ten patients
received postoperative chemo-radiation for adjuvant therapy. The patients’clinical stages according to UICC TNM classification (6th Ed. ) were B: 1, A:
2, B: 2, : 10, and A: 1. The non-surgical patients received radiotherapy of 50.4
Gy in 28 fractions, and post-operative patients 39.6Gy, from a linear accelerator by 3D-CRT. GTV was defined to cover the primary tumor and regional
involved lymph nodes on CT for the non-surgical group, while for the postop-erative group it was defined to cover the surgical clip marking placed by thesurgeon during surgery. Weekly intravenous administration of Gemcitabine(40mg/m2) was done during the irradiation period. Adjuvant chemotherapyof Gemcitabine (1000mg/body) with oral 5-FU agent(TS-1) for 8 weeks wasdone following completion of chemo-radiation. CTCAE ver.3.0 and RTOG /EORTC criteria were used to evaluate toxicity. Initial local response was evaluated by tumor size reduction on CT images according to RECIST. KaplanMeier analysis was used to calculate cumulative overall survival.
Results: Median follow-up time was 19 months. The local tumor responses
were: SD: 4, and PD : 2. Only 2 patients had Grade 3 neutropenia. Twopatients had a break longer than 8 days during radiation treatment course
because of neutropenia. There were no terminations of the radiation treatment course. No Grade 3/4 late toxicity or treatment-related death occurred.
The median overall survival time was 13 months for the non-surgical group,and 22 months for the postoperative group. .
Conclusions: Radiotherapy with concomitant weekly administration of Gemcitabine appears to be a feasible and effective adjuvant or palliative treatment
for patients with locally advanced pancreatic cancer. However, additional clinical studies are required to confirm the therapeutic efficacy.
973 poster
RANDOMIZED TRIAL OF RADIOSURGERY VERSUS SURGERY,
EACH WITH WHOLE BRAIN RADIOTHERAPY, FOR SOLITARY
BRAIN METASTASES
D. Roos1
1
R OYAL A DELAIDE H OSPITAL, Radiation Oncology, Adelaide, Australia
Purpose: This randomized non-inferiority trial was designed to assess
whether radiosurgery plus adjuvant whole brain radiotherapy (RS+WBRT) is
as effective as surgery plus WBRT (S+WBRT) for cancer patients with a solitary brain metastasis, with respect to overall survival and quality of life.
Materials: Major inclusion criteria were a history of systemic cancer within
5 years and enhanced MRI-confirmed solitary brain metastasis suitable forboth radiosurgery and surgery. All patients were to receive WBRT (30 Gy
in 10 fractions). The radiosurgery dose was slightly modified from Radiation
Therapy Oncology Group 90-05 guidelines. Between February 2003 and April
2009, 40 patients were considered eligible, 22 consented to randomizationand 21 were analyzed (RS+WBRT 11, S+WBRT 10). The trial was closed
early due to slow accrual.
Results: Estimated median overall survival times for RS+WBRT and
S+WBRT patients were 6.2 and 2.8 months respectively (hazard ratio 0.53,
95% confidence interval 0.201.43, P=0.20). Corresponding median failurefree survival times were 3.1 and 1.7 months (P=0.20). For 19 "per protocol"
patients, 2 of 10 in the RS+WBRT arm had distant intra-cranial failure (onealso had local failure) and 3 of 9 S+WBRT patients had distant intra-cranial
failure (no local failures). There were no grade 34 late radiation toxicities. Twomonths after commencing treatment, there were no significant differences inquality of life between the arms.
Conclusions: In this small randomized trial we found no evidence that
RS+WBRT is inferior to S+WBRT for patients with a solitary brain metastasis
suitable for either strategy. (ClinicalTrials.gov number, NCT 00124761)
974 poster
RETROSPECTIVE ANALYSIS OF COMMERCIAL MONTE CARLOTREATMENT PLANNING SYSTEM FOR LUNG CANCER
H. Miura1 , M. Norihisa1 , R. J. oh2 , H. Shiomi2 , K. Norihiko3 , I. Toshihiko2
1
M IYAKOJIMA IGRT CLINIC, Department of Medical Physics, Osaka, Japan
2
M IYAKOJIMA IGRT CLINIC, Department of Radiotherapy, Osaka, Japan
3
H YOGO C OLLEGE OF M EDICINE, Department of Radiology, Nishinomiya,Japan
Purpose: We performed a retrospective analysis of dosimetry concerningstereotactic body radiation therapy (SBRT) for 53 lung cancer patients treatedat our institution with the commercial Monte Carlo (MC) algorithms to evaluate
the variation in actual tumor and normal lung doses delivered.
Materials: Fifty-three patients (CTV: 0.5-33.3cc, PTV: 7.7-102cc) who underwent SBRT for the lung between April 2009 and August 2010 were retrospectively reviewed. The SBRT treatment plans were performed on iPlan RT
Dose (BrainLAB) treatment planning system using the prescribed dose was
48Gy/4fractions to the PTV periphery with PB calculations. Using beam arrangement and monitor units used for the actual treatment, dose distributions
were recomputed with the heterogeneity correction turned on using the MC.
MC calculation were performed with full MLC geometry simulation with a spatial resolution of 2 mm and a variance of 1%. We evaluated the dose-volume
measurement for the CTV: D99, PTV: D95 and lung (V20 V10 V5) Two-sided,
paired Student’s t tests were used to evaluate these differences. We madethe virtual phantom and evaluated concerning CTV size (0.3-22.3cc), different lung (CT value:-650-750-850) density, different CTV density (CT value:
0.-200,-400), and effect of the tumor location (distance from chest wall).
Results: The dose covering 99% volume of CTV (D99) based on the PB was
11.4% (range 3% to 22%) lower on average than planned with MC. The dose

S 369

covering 95% volume of PTV (D95) based on the PB was 19.4% (range 10%
to 33%) lower on average than planned with MC. The lung volume receiving greater than 20Gy (V20) was 10% (range 3% to 29%) higher on averagecompared to the MC. There was a significant difference between dose calculations with PB and the MC algorithms (p<0.001).The dose distributions
depends on the size and the tumor location in relation to beam orientationand field size. With the virtual phantom calculations, the dose were lower
for smaller field size, lower lung density, lower CTV density, greater distancefrom the chest wall.
Conclusions: Statistically significant dose differences were found with theeach algorithm. Our clinical protocol for the lung cancer is supposed thatprescribed dose is 44Gy/4 fractions to the CTV with MC calculations. We areplanning to implement MC calculations for lung cancer patients.
975 poster
SALVAGE HIGH-DOSE-RATE BRACHYTHERAPY FOR RECURRENTESOPHAGEAL CANCER
S. Wong Hee Kam1 , L. Quero1 , S. Rivera1 , S. Michaud1 , C. Maylin1 , C.
Hennequin1
1
H ÔPITAL S AINT-L OUIS, Service de Radiotherapie, Paris, France
Purpose: To evaluate outcomes after salvage high-dose-rate intraluminal
esophageal brachytherapy (HDR-IEBT) for previously irradiated patients withrecurrent esophageal cancer.
Materials: 32 patients were treated with curative intent using HDR
brachytherapy for inoperable local esophageal cancer from january 1999 tonovember 2008. The median age was 65 years. They had received external
radiotherapy (minimal dose of 40 Gy) for previous esophageal cancer (n =26)
or thoracic cancer (n=6). At time of recurrence, none of them had visceralmetastasis, 2 patients had local node metastasis. Brachytherapy consistedof 4-6 fractions of 5 Gy (mean dose of 22.4 Gy), delivered 1 cm from thesource, with a margin of 2 cm above and below the tumor.
Results: The complete histologic response rate, evaluated at 1 month after
HDR-IEBT, was 59%, significantly associated to full treatment (87.5% of thepatients) (p=0.01). The estimated overall and cause-specific median survival
rates were 9.6 months and 10.4 months. At 1 year, the overall survival and thecause-specific survival rates were 34.3% and 36.9%, and at 3 years, 17.6%
and 18.9% respectively. Severe acute toxicity occured in 6 patients (19%)
including treatment-related fistulas in 2 patients (6%) and one severe case of
esophagitis leading to death in these 3 patients (9%). Severe late strictures
occured in 5 patients, leading to death in one case.
Conclusions: HDR-IEBT may be a salvage treatment for selected patientswith recurrent esophageal cancer after external radiotherapy. It offers a 3years cause-specific survival of 18.9% in patients without other therapeutic
alternative.
976 poster
SINGLE AND MULTI-SESSION RADIOSURGERY TREATMENT FOR
BRAIN METASTASES. SINGLE INSTITUTION, 5 YEARS EXPERIENCE ANALYSIS.
I. Milanesi1 , M. Marchetti1 , L. C. Bianchi2 , G. Beltramo2 , C. L. Solero1 , G.
Broggi1 , L. Fariselli1
1
F ONDAZIONE IRCCS I STITUTO N EUROLOGICO C B ESTA, Milano, Italy
2
C ENTRO D IAGNOSTICO I TALIANO, Milan, Italy
Purpose: The treatment of brain metastases is in changing. Many technicalradiotherapy options are available and actually under clinical evaluation. In
the present study, we retrospectively evaluated the efficacy and toxicity ofboth single and multi-session radiosurgery
Materials: In the period between June 2004 and December 2009, 443 patients referred to our Institute for a metastatic disease of the brain. In thisperiod 729 lesions were treated by either single or multi-session radiosurgery
with CyberKnife (CK). The KPS was always higher than 70. A prior WBRT
was performed in 107 patients. Five-hundred-seventy-two patients weretreated by single session radiosurgery. The mean dose was 19 Gy, encompassed by the 82 % isodose line. The mean target volume was 2,8 cc (median
1,4). One-hundred-fifty-seven patients were treated by multi-session radiosurgery. The mean dose was 23,4 Gy delivered in 2 to 5 fractions. The mean
reference isodose line was the 79 %. The mean tumor volume was 14,6 cc(median 10,3 cc). The number of treatments for each patient ranged from 1
to 9. All patients were evaluated with clinical and radiological follow-up using
MRI after 2 months and every 4 months thereafter
Results: Actuarial overall survival was 69,3%, 51,7%, 31,6% and 23,3% at 6,
12, 24 and 36 months, respectively. The median overall survival was medianoverall survival 12,7 months (95% CI: 9.0-16.4). The median follow-up period
was 46 months (95% CI: 38.1-54.7) According to the McDonald criteria, after
six months, CR was achieved in 18,7% of the lesions, PR in 22,7%, and SD
in 40%. The 16,7% of the treated lesion showed a progression. The causeof death was the systemic progression of the disease in 68% of the patientsand the intracerebral progression in 19%. Only the 10% of the patients diedbecause of the treated lesion. RPA class has been confirmed as a prognostic

S 370OTHERS

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factor. Upfront WBRT had no impact on survival and local control. Neurological status improved in 65% of pts. Adverse event were rare and usually mild
(4 patients had a RTOG toxicity > grade 2)
Conclusions: This experience suggest that both single and multi-session
radiosurgery should be proposed as an alternative approach to WBRT in thetreatment of one to three metastatic lesions in selected patients
977 poster
SPOT SCANNING PROTON BEAM THERAPY DELIVERED AT THE
PAUL SCHERRER INSTITUT FOR INTRACRANIAL AND EXTRACRANIAL MENINGIOMAS
D. C. Weber1 , R. Schneider2 , T. Koch3 , C. Ares2 , G. Goitein3 , E. Hug2
1
G ENEVA U NIVERSITY H OSPITAL, Radiation Oncology, Geneva, Switzerland
2
PAUL S CHERRER I NSTITUTE (PSI), Center for Proton Therapy, Villingen,
Switzerland
3
PAUL S CHERRER I NSTITUTE (PSI), Center for Proton Therapy, Villigen PSI, Switzerland
Purpose: To assess the long term clinical results of spot scanning proton
beam therapy (SSPT) in the treatment of meningiomas.
Materials: Forty patients with meningioma (histologically proven 35/40) weretreated with SSPT between 1997 and 2010. Thirty nine patients had intracranial meningioma and 1 patient had a spinal meningioma. Mean age was
47.1±17.9 years. For patients undergoing surgery, 23, 10 and 2 patients had
a diagnosis of WHO grade 1, 2 and 3 meningioma, respectively. The female
to male ration was 3.4. The median administered dose was 56.0 Gy E (range,
52.2 68.4). Gross tumor volume (GTV) ranged from 0.76 to 546.5 ml (median, 24.1). Late toxicity was assessed using the NCI CTCAE (v3.0) grading
system. Mean follow-up time was 62.7 months and all patients were follow-up> 6 months.
Results: Six patients presented with tumor recurrence and 6 patients diedduring follow-up, of which 4 of tumor progression. Five-year actuarial local
control and overall survival rates were 85.3% and 82.5%, respectively. The
cumulative 5-year grade ≥ 3 late toxicity-free survival was 85%. On univariate analysis, LC was negatively influenced by WHO grade (p=0.003), GTV(p=0.013) and male gender (p=0.058).
Conclusions: SSPT is a safe and effective treatment for patients with untreated, recurrent or incompletely resected meningiomas. WHO grade andtumor volume was an adverse prognostic factor for local control.
978 poster
STEREOTACTIC RADIOSURGERY (SRS) IN PATIENTS PREVIOUSLY TREATED WITH EXTERNAL BEAM RADIATION THERAPY
K. Adamska1 , A. Lewandowska1 , D. Jezierska1 , S. Smol2 , T. Majewski2 , W.
Liebert2 , A. Skrobała3
1
G REAT P OLAND C ANCER C ENTRE, Department of Radiation Oncology,
Poznan, Poland
2
U NIVERSITY H OSPITAL, Neurosurgery, Poznan, Poland
3
G REAT P OLAND C ANCER C ENTRE, Department of Medical Physics andRadiation Safety, Poznan, Poland
Purpose: Stereotactic radiosurgery (SRS) is used for the definitive treatmentof recurrence of inoperable brain tumours. We wished to determine the efficacy of SRS in the treatment of patients who had received prior externalbeam radiation therapy (EBRT) to the treated site.
Materials: Records were reviewed for the 25 patients enrolled into a SRS
prospective observational database at Great Poland Cancer Center between
2005 and 2010.
Results: The median age of the patients was 54 years.Dose per fraction
ranged from 10Gy to 20/Gy, median 14.7/Gy, depending on the anatomic
site treated and tumour size.Overall survival (OS) and local control (LC) were
estimated. Analysis was used to evaluate the effect of patient- and treatmentrelated factors on the clinical endpoints and toxicity.
Conclusions: STR appears to be an effective, well-tolerated local therapy forrecurrence of small lesions . These data suggest that re-irradiation using SBR
treatment is of low toxicity and have minimal side effects.Further investigation
with larger patient cohorts is necessary.

979 poster
STEREOTACTIC RADIOSURGERY FOR THE TREATMENT OFMELANOMA AND RENAL CELL CARCINOMA BRAIN METASTASES
P. Goetz1 , S. Lwu1 , M. Aryaee1 , C. Menard2 , N. J. Laperriere2 , M.
Bernstein1 , G. Zadeh3
1
TORONTO W ESTERN H OSPITAL - U NIVERSITY H EALTH N ETWORK, Divisionof Neurosurgery, Toronto, Canada
2
P RINCESS M ARGARET H OSPITAL, Department of Radiation Oncology,
Toronto, Canada
3
U NIVERSITY H EALTH N ETWORK, Division of Neurosurgery, Toronto,
CanadaPurpose: Renal cell carcinoma (RCC) and melanoma brain metastases are
traditionally considered radioresistant. However, stereotactic radiosurgery(SRS) is becoming more accepted as a treatment option. The aims of thisstudy were to evaluate the role of SRS for local control for these lesions bothwith and without prior whole brain radiotherapy (WBRT), and to identify predictors of response.
Materials: All RCC and melanoma patients treated with Gamma Knife SRS
between July 2006 and September 2010 were reviewed. Clinical, radiologicaland dosimetry parameters were examined as predictors of response to SRS.
Results: Ninety-nine lesions (41 RCC, 55 melanoma) in 33 patients wereanalysed. Median age was 57 years. 56% of lesions had been treated previously with WBRT while the remainder received SRS alone upfront. Medianprescription dose was 21 Gy (range, 15-24). Median target minimum dosewas 20.2 Gy (range, 11.62-31.85). Median and mean tumour volumes were0.39 cm3 and 1.3 cm3, respectively (range, 0.003 to 13.36 cm3). Medianfollow-up was 5 months (range, 1-41 months). Median RTOG conformality
index was 1.96 (range, 1.04-9.76). Local control rates were 93%, 91%, 85%,
72%, and 57.4% at 3, 6, 12, and 18 and 24 months respectively. Three (3.1%)
lesions required local salvage therapy (surgical resection). Twenty-four (25%)
lesions received WBRT 2 to 21 months after SRS for distant brain failure.
Conclusions: Stereotactic radiosurgery is a valuable option for local control
of RCC and melanoma brain metastases. Based on our institutional data,
delay of WBRT is safe without significant difference in local control rates. We
also report on the factors that are predictive of response to SRS for RCC andmelanoma metastases.
980 poster
STEREOTACTIC RADIOSURGERY USING X KNIFE: AN INSTITUTIONAL AUDIT
R. Achari1 , A. Bhanage2 , V. Sathyanarayanan3 , J. Bhangale3
1
TATA M EDICAL C ENTER, Department of Radiation Oncology, Kolkata, India
2
RUBY H ALL C LINIC K AMALNAYAN B AJAJ C ANCER C ENTER, Department of
Neurosurgery, Pune, India
3
RUBY H ALL C LINIC K AMALNAYAN B AJAJ C ANCER C ENTER, Department ofMedical Physics, Pune, India
Purpose: there exists a definite paucity in literature as far as Indian experience of stereotactic radiosurgery is concerned. In order to circumvent thesame, an institutional audit was undertaken for all the patients who underwent
stereotactic radiosurgery over a period of three years. All patients underwent
radiosurgery using the linear accelerator. Only those patients were included
for analysis who had a follow up of at least six months in order to give us theexact insight into tumour response or complications.
Materials: Fifty five patients who underwent stereotactic radiosurgery using
the linear accelerator in our institute over the last three years with a follow
up of at least 6 months were evaluated. All these patients were treated on
the Siemens Oncor Impression Unit with Brainlab Millenium micromultileaf
collimator. For target delineation all patients underwent a CT angiography
and/ or DSA for vascular malformations and a contrast enhanced MRI for theremainder of the lesions. In order to deliver radiosurgery, multiple conformal
arcs were used in 55%, conformal beams in 40% and intensity modulated
radiosurgery in 5% of the lesions. Data was analysed using SPSS version
17.0.
Results: Vascular malformations, both arteriovenous malformations (AVM)
and non AVM lesions were the most commonly treated entity accounting for
33% (19) of the lesions treated. This was followed by acoustic schwannomas 31% (17), of which 2 patients had bilateral lesions, metastases 13% (7),meningiomas 9% (5), gliomas 6% (3) and other lesions like pineal tumours,
pituitary adenoma and third nerve schwannomas accounted for the remaining
8%. The distributions of lesion types appear consistent with world literature(ref3). Majority of the patients were in the fifth decade of life and there was
equal distribution between both sexes. On subset analysis, the demographic
profiles remained the same for vascular malformations and acoustic nerve tumours.The mean volume of vascular malformations was 11 cc and received a
median dose of 22 Gy to the periphery of the lesion. Three patients (6%) had
a post procedure generalized tonic clonic convulsion, 1 patient had a sigmoid
sinus thrombosis and 1 patient rebled at one year. Four patients (21%) havea complete angiographic response at 18 months. The angiographic obliteration rates appears lower than that quoted in literature of 35% -90% (ref 1,2)
at three years possibly because our evaluation is at a median followup of 18

months.The mean volume of acoustic tumours was 4 cc and received a median dose of 12 Gy to the periphery of the lesion. Three patients (17%) haveradiological partial response at 18 months, of which only one patient has objective improvement in pure tone audiometry. The remainder of this subset
has stable disease on imaging. The numbers of patients in the remainder
diagnosis are insufficient for independent evaluation. However, at a medianfollow up of 18 months none of the patients have clinical or radiological complications of radiosurgery.
Conclusions: there exists a definite paucity in literature as far as Indian experience of stereotactic radiosurgery is concerned. With rapid adoption of highend technology in the Indian subcontinent over the last 5 years it is essentialthat more centers audit and peer review their clinical practice for delivery ofsafe and quality assured treatment. Our results are consistent with that published in literature (ref3, 4) and we await further follow up.
REFERENCES:
1. FriedmanWA, Bova FJ. Linear accelerator radiosurgery for arteriovenous
malformations. J Neurosurg 77:832-41, 1992
2. FriedmanWA, Bova FJ, Mendenhall WM. Linear accelerator radiosurgery
for arteriovenous malformations: the relationship of size to outcome. J Neurosurg 82:180-189, 1995.
3. Hamri AK, Monk J, Plowman PN. Stereotactic radiosurgery at St
Bartholomew’s hospital: third quinquenial review. The Br J Radiol, 78: 384393, 2005.
4. Kondziolka D, Lunsford D, McLaughlin MR, et al. long term outcomes afterradiosurgery for acoustic neuromas. N Engl J Med, 339:1426-33, 1998.
981 poster
SURVIVAL PREDICTION BY MIRNA EXPRESSION PATTERNS INGLIOBLASTOMA
M. Niyazi1 , F. Zehentmayr1 , O. Niemoeller1 , H. Kretzschmar2 , C. Belka1
1L.-M AXIMILIANS -U NIV., K L .
G ROSSHADERN, Radiation Oncology,
München, Germany
2
L.-M AXIMILIANS -U NIV., K L . G ROSSHADERN, Neuropathology, München,
Germany
Purpose: In order to define new prognostic subgroups in patients withglioblastoma we performed a miRNA screen (> 1000 miRNAs) from paraffintissues. Complete follow-up data and data on the MGMT methylation patternwere available. We analyzed whether there were MGMT-independent miRNA
patterns with prognostic significance.
Materials: 35 patients treated in a single institution with surgery and postoperative radio(chemo)therapy from 7/2005 -8/2008 were included in this retrospective analysis. For microarray analysis the febit biochip "Geniom® Biochip
MPEA homo sapiens" was used. Total RNA was isolated from FFPE slides,
altogether 1100 different miRNAs were analyzed.
Results: It was possible to segregate a distinct miRNA expression patter inpatients with glioblastoma. The defined miRNA pattern significantly predicted
early death versus long-term survival (split at 450 days) in a (p = 0.015). The
pattern and the prediction was independent of the MGMT status.
Conclusions: To our best knowledge this is this first set of data defining a
prognostic role of miRNA expression patterns in patients with glioblastoma.
Having defined such a pattern it is now possible to prospectively validate theresults.
982 poster

TARGETED RADIONUCLIDE THERAPY FOR METASTATIC PITUITARY CARCINOMA
N. Fersht1 , M. Gaze1 , S. Short2 , J. Bomanji3 , M. Powell4
1
UCLH NHS F OUNDATION T RUST, Oncology, London, United Kingdom
2
U NIVERSITY C OLLEGE L ONDON H OSPITAL NHS T RUST, Oncology,
London, United Kingdom
3
UCLH NHS F OUNDATION T RUST, Nuclear Medicine, London, United
Kingdom
4
N ATIONAL HOSPITAL FOR N EUROLOGY AND N EUROSURGERY, Neurosurgery, United Kingdom
Purpose: We present an innovative treatment for a 64 year old patient withmetastatic pituitary carcinoma.He presented originally aged 41 years in 1987
with bi-temporal hemianopia and had a frontal craniotomy and resection ofa pituitary adenoma, followed by adjuvant radiotherapy.In 2006, he underwent transphenoidal resection of his recurrent pituitary adenoma. MRI at thetime demonstrated meningeal thickening throughout the neuraxis and leptomeningeal nodules infra and supratentorially.By June 2009 the primary tumour was stable but the meningeal thickening and leptomeningeal nodules
had increased in size and number.In August 2009 one of the spinal nodules
was excised and confirmed the diagnosis of metastatic pituitary carcinoma(histologically resembling his original pituitary adenoma, both lesions being
cytologically bland without elevation of the proliferation index or over expression of p53).Pituitary carcinoma is an extremely rare condition (between 0.1 0.5% of all pituitary tumours) diagnosed by the presence of craniospinal and /or systemic metastases, rather than local invasion. It is thought to arise fromS 371

a benign adenoma rather than de novo. No standard chemotherapy regime
exists. Various combinations of drugs have been tried but with only temporary
responses seen.
Materials: As significant numbers of neuroendocrine tumours express somatostatin receptors, we carried out a 68Ga-octreotate whole body PET-CT
scan. This confirmed the presence of an Octreotate-avid pituitary adenoma
recurrence with cerebral and bony skull Octreotate-avid metastases.We decided to commence treatment with 177-Lutetium-Dotatate. This consistsof a somatostatin peptide analogue, coupled with a complexing moiety(DOTA) labelled with the beta-emitter Lutetium-177. By targeting somatostatin receptor-positive tumours we may deliver a tumoricidal radiation dose.
The treatment is well tolerated with minimal side-effects, and easy to administer requiring only a short in-patient stay in a radiation protected environment.
Results: He underwent the full treatment course uneventfully.
Reassessment imaging demonstrated stable disease.
Conclusions: At UCLH we have now treated 17 patients with neuroendocrine tumours with 177-Lutetium-Dotatate (including 4 children), each
receiving up to four administrations three months apart. However, this is our
first patient with a metastatic pituitary carcinoma.
983 poster
THE 3D QUANTIFICATION OF DELIVERED IMRT DOSE DISTRIBUTIONS FOR MOBILE TARGETS
S. Hoffe1 , D. Opp1 , K. Latifi1 , J. Pritz1 , R. Shridhar1 , T. Dilling1 , G. Zhang1 ,V. Feygelman1 , K. Forster1
1
H. L EE M OFFIT C ANCER C ENTER, Radiation Oncology, Tampa, USA
Purpose: Multiple publications report the degradation of delivered dose distributions for mobile tumor volumes being treated with MLC based IMRT. The
discrepancy between planned and delivered doses has been attributed to theinterplay between the dynamic delivery and the respiration induced motion.
We hypothesize that using an ITV planning approach coupled with compensator based IMRT will result in better agreement between planned and delivered dose distributions.
Materials: IMRT and compensator-based plans were generated in our Pinnacle treatment planning system (TPS) for a series of previously treated patients(5 pancreatic, 6 esophageal, and 4 liver cases). The PTV coverage and OAR
sparing were matched yielding nearly identical DVHs. The deliveries of theseplans were measured with a bi-planar diode array (Delta4 ) with a 5 mm spacing between diodes in the central 6 cm and 1 cm spacing for the rest of the
20 cm detector. The Delta 4 was placed on an acrylic table manufactured
and programmed for two dimensional motion. The motion platform moved
on an engraved ramp with a 10◦ inclination with a motion pattern that wasdetermined from a 4D CT of an esophageal case. For the specific data set
presented, motion was varied by amplitude (24, 14.4, 10, and 6 mm) while
frequency remained at 12 cycles per minute. Gamma analysis, using a 3%,
3mm passing criteria, was performed by using motion measurements as themeasured doses and static measurements as the reference doses. The measurements were repeated 15 times for 7 cases to examine the effect of phaseon these results. We chose three cases where measurements showed significant differences in passing rates for the two delivery techniques while theremaining four showed only minor differences in passing rates.
Results: The average percentage of motion dose points that agreed with thestatic measurement for motion of 24, 14.4 and 10 mm with compensators was
significantly higher than with MLCs. For 24 mm motion and compensators,
the Avg = 95.6% (STD=1.6) while the MLC delivery was 86.8 (STD = 3.6) p= 0.025. For 14.4 mm motion and compensators, Avg = 99.0% (STD = 1.3)
compared to MLC Avg = 93.6% (STD = 2.0) p = 0.015. For 10 mm motion andcompensators, Avg = 100.0% (STD = .02) while MLC Avg = 97.5 (STD = 2.9)
p=0.024. For 6 mm motion, both compensator and MLC deliveries averaged
over 99% agreement with the static delivery. The reproducibility analysis forthe 7 multiply-retested cases showed an average passing rate of 95.8% (SD= 1.1%) for compensators and 84% (SD = 4.8%) for MLC.
Conclusions: The interplay between the dynamic delivery techniques of
IMRT and respiration induced motion significantly degrades the delivered
dose distribution with MLC based techniques as compared to compensator
based treatment for motion larger than 10 mm. A single measurement that includes motion may also not accurately reflect the delivered dose distribution,
particularly with MLC-based IMRT.
984 poster
THE DEVELOPMENT OF A SCREENING TOOL FOR THE PROVISION OF RADIOTHERAPY PATIENT CENTRED SUPPORTIVE CARE
J. Maamoun1
1
T HE O DETTE C ANCER C ENTRE - S UNNYBROOK H EALTH S CIENCESC ENTRE, Toronto, Canada
Purpose: Individuals undergoing radiotherapy for cancer may experience awide range of supportive care needs that are frequently not addressed. A
screening tool was designed for radiation therapists to quickly identify thosepatients that require additional intervention during the course of their radiation

S 372OTHERS

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treatment, allowing early and timely referral, and facilitating the provision ofquality in-depth patient centred supportive care.
Materials: A comprehensive and itemized screening tool was designed to
identify the patient distress level and captures the patient desires to be helpedwith specific concerns. It informs us of alternative help provided. The tool wasadministered simultaneously with the quality of life questionnaire (QLQ-C30).
One hundred and fifteen radiotherapy patients completed both instruments on
three occasions; the first two were two days apart, and the third two weeks
later. The degrees of agreement between the responses on the first two occasions (the first comparison reliability) and those between the first and lastoccasion (the second comparison sensitivity) were analyzed for both instruments. Correlations between the responses on the two instruments were
examined (validity).
Results: For the screening tool both McNemar’s test and the simple kappa
statistic were used. The former showed a 25% decrease in agreement fromthe first to the second comparison. The latter showed a shift in over 97% of
the items on the screening tool from a higher agreement to a lesser agreement. For the QLQ-C30 the Pearson correlation coefficient fell on the average from 0.749 to 0.573 for the first and the second comparisons. Statisticallysignificant correlations were established between the responses on the two
instruments with p-values < 0.0001 for > 95% of responses.
Conclusions: The new screening tool was proven to be reliable, sensitiveand valid. It is anticipated that the screening intervention will allow clinicians
to standardize and formalize their approach to supportive care in radiotherapy
out-patient clinics and enhance their capacity to identify and address patientconcerns in a timely manner.
985 poster
THE IMPACT OF PET/CT ON RADIOTHERAPY OF ANAL CANCER
J. Sveistrup1 , A. Loft2 , A. K. Berthelsen1 , B. M. Henriksen3 , S. A.
Engelholm1
1
R IGSHOSPITALET, Department of Radiation Oncology, Copenhagen,Denmark
2
R IGSHOSPITALET, PET and Cyclotron Unit, Department of ClinicalPhysiology and Nuclear Medicine, Centre of , Copenhagen, Denmark
3
R IGSHOSPITALET, Department of Radiology, Section of Ultrasound X4123,
Copenhagen, Denmark
Purpose: To compare Transanal endoscopic Ultrasound (TAUS) and abdominal Ultrasound (US) with PET/CT in detecting regional lymph node metastases in patients with anal cancer. The impact of the PET/CT on the treatment
plan was evaluated.
Materials: Ninety-five (95) patients referred to our clinic between July 1st
2005 and December 31 2009 were retrospectively reviewed. All patients
had biopsy-proven primary squamous cell cancer of the anal canal. There
were 65 females (68%) and 30 males (32%), and the median age was 58(age range 35-88 years). All patients were staged during anaesthesia with 3Dimensional Transanal Endoscopic Ultrasound (TAUS) and US of the inguinal
regions. Seventy-seven (77) patients were furthermore examined with US of
the abdomen. All 95 patients underwent whole-body FDG-PET/CT as partof radiotherapy planning. The detection of suspicious perirectal, internal iliac
and inguinal lymph nodes by TAUS/US and PET/CT, respectively, was evaluated. Suspicious perirectal and internal iliac lymph node were not biopsied.
Suspicious inguinal lymph nodes were biopsied with few exceptions.
Results: Twenty-eight patients were diagnosed with suspicious perirectal
node metastases. TAUS identified 24 of the patients. PET/CT identified 15,
nine of which had not been seen on TAUS. Eleven patients were diagnosed
with suspicious internal iliac node metastases, all of which were detected on
PET/CT. One of these patients had not been examined with abdominal US.
US diagnosed suspicious internal iliac nodes in one patient.Inguinal nodes
suspicious of malignancy were visualized on either US or PET/CT in 41 patients. Seventeen (17) of these had confirmed malignant disease on biopsy,
and 15 had confirmed benign disease. All 17 patients (100%) with malignant
inguinal nodes were diagnosed by PET/CT, whereas US identified 16 of the
17 patients (94%). PET/CT detected suspicious inguinal nodes in 10 patients,
which had not been seen on US. On biopsies one of these was proven malignant, three were benign and six did not have any biopsy. Five patients had
their treatment changed from radiotherapy alone to concomitant chemoradiotherapy due to the finding of lymph node metastases on the PET/CT. Twoof these patients had suspicious perirectal nodes, one patient had internal
iliac nodes, and the final two patients had inguinal lymph node metastasis, ofwhich one was proven malignant on biopsy, and in the other case no biopsy
was performed.Six patients were radiated on either one or both inguinal regions as a consequence of additional inguinal node metastases detected on
the PET/CT.

Conclusions: Compared to TAUS/US,PET/CT seems important for especially the N2/3-stage in anal cancer and resulted in additional inguinal irradiation of either one or both sides in six patients. The detection of additional
lymph node metastases on PET/CT resulted in five patients receiving concomitant chemoradiotherapy instead of radiotherapy alone. It is a limitation ofthis study that not all suspicious lymph nodes were biopsied. However, thetrue sensitivity and specificity of any staging technique cannot be determined
unless the patients undergo a full lymph node exairesis. Finally, a minor partof the patients had not been examined with US of the abdomen which makes
it impossible to compare PET/CT and US regarding the detection of internal
iliac metastases in these cases.
986 poster
THE INFLUENCE OF FRACTIONATION RADIOTHERAPY REGIMENON THE SURVIVAL OF PATIENTS WITH MUSCLE-INVASIVE BLADDER CANCER
A. Popov1 , M. Valkov2 , L. Parygina1
1
R EGIONAL C LINICAL O NCOLOGY H OSPITAL, Radiation Oncology,
Arkhangelsk, Russian Federation
2
N ORTHERN S TATE M EDICAL U NIVERSITY, Department of Radiology andRadiation Oncology, Arkhangelsk, Russian Federation

Purpose: Radiotherapy is one of the effective methods of bladder-preserving
treatment in muscle-invasive bladder cancer (MIBC). Aim of the study is tocompare long-term survival in patients with after conventional (CRT) or accelerated, hyperfractionated radiotherapy (HFRT), and to determine the prognostic influence of such factors as age, gender, stage of disease, and treatment regimen.
Materials: A prospective analysis of MIBC 48 patients, treated with HFRT
(1.25 Gy b.i.d. to 70 Gy) from 2007 through 2009 was performed. Ninety
four case-reports MIBC patients treated with CRT from 2003 through 2006
were retrospectively analyzed as controls. All patients received radiotherapy
as a part of bladder-conserving treatment at the Arkhangelsk regional oncology hospital and were biopsy-confirmed (transitional-cell cancer in all cases).
Two-dimensional external beam radiotherapy consisted of irradiation to small
pelvis to 40 Gy BED, than, after 2 weeks split, to bladder only to total 68-74
Gy BED. Additionally intravesical chemotherapy was performed after completion of RT. Transurethral resection and cystectomy were used only for savage.
Actuarial survival curves for overall survival were computed using the KaplanMeier method and compared by log-rank test. Influence of age, gender, tumor
stage, and treatment method on survival was studied by Cox regression.
Results: No significant difference between HFRT and CRT groups was observed for age (mean age 63.59 (SD, 9.474) years vs 64.53 (SD, 9.318)
years (t=0.561, =0.576)) and gender (proportion of men 76.1% vs 87.2%(χ2 =2.795, =0.143)), respectively. HFRT and CRT groups differed by thestage of BC: T2, 82.6% vs 57.4%; T3-4, 17.4% vs 42.6% of patients, respectively (χ2 =8.679, =0.004). Six patients died in the HFRT group in 116 month after treatment, while 45 patients died in 0-58 months in the control group. The overall survival was significantly higher in the HFRT group(χ2 =5.546, =0.019), though it turned to tendency after correction for T-stage.
No associations of overall survival with selected prognostic factors in multiple
Cox regression analysis were observed, although the method of treatment(HFRT vs. CRT) had the most contribution to the overall survival (OR=0.416,
CI=0.172-1.003, p=0.051).
Conclusions: HFRT can be offered as an alternative option to CRT, as theoverall survival rates of bladder invasive transitional cell carcinoma treatment
with HFRT are comparable to those of CRT. The absence of benefit after
HFRT may be due to the limited number of observations, therefore the study
will be continued.
987 poster
THE RECENT EFFECT OF RADIOTHERAPY COMBINED WITHCOMPOUND KUSHEN INJECTION FOR ELDERLY PATIENTS WITH
ESOPHAGEAL CANCER
Q. Shao1
1
S HANDONG C ANCER H OSPITAL, Departments of Radiation Oncology andCell Biology, Jinan, China
Purpose: To observe the recent effect of radiotherapy combined with compound Kushen injection for elderly patients with esophageal cancer.

Materials: Fifty-two elderly patients no less than 75 years old were diagnosedby pathology or cytology confirmed. The patients were randomly divided into
treatment group and control group and each group had 26 cases. The treatment group was treated with radiotherapy combined with compound Kushen
injection and the control group was treated with radiotherapy alone. The total dose of two groups was 5666Gy/2833 fractions.The median dose was60Gy. Symptoms ameliorated and adverse effects during radiotherapy wereobserved.The treatment effect were evaluated 1 month after radiotherapy.
Results: Symptoms ameliorated were earlier and better in treatment groupthan control group. The adverse effects were less in treatment group thancontrol groupp0.05. The rates of complete and partial response in treatmentgroup and control group were 34.6% and 53.8%, 26.9% and 53.8% , and thetotal response rate was 88.5%80.8%p0.05respectively.
Conclusions: Radiotherapy combined with compound Kushen injection fortreatment elderly patients with esophageal cancer shows to reduce adverse
effects and imoprove Symptoms and it may be to improve efficacy.
988 poster
TO INVESTIGATE WHETHER THERE IS EVIDENCE OF A CORRELATION BETWEEN THE PLANNING TARGET VOLUME (PTV)
AND THROMBOCYTOPENIA DURING CONCOMITANT TREATMENT
WITH RADIATION AND DAILY TEMOZOLOMIDE IN PATIENTS WITH
NEWLY DIAGNOSED GBM
M. MacKinnon1 , A. Williamson1
1
T HE B EATSON W EST OF S COTLAND C ANCER C ENTRE, Cancer Centre,
Glasgow, United Kingdom
Purpose: Concomitant chemo-radiotherapy is the gold standard treatment forpatients with glioblastoma (GBM). Although generally safe, a small percentage of patients suffer marked myelosuppression, particularly thrombocytopenia. Predisposing factors for this are not clear. Large volume radiotherapy
can also be associated with haematotoxicity and we wished to see whether
glioblastoma patients with larger radiotherapy treatment volumes were at
greater risk of thrombocytopenia.To investigate whether there is evidence ofa correlation between the Planning Target Volume (PTV) and thrombocytopenia during concomitant treatment with radiation and daily Temozolomide inpatients with newly diagnosed GBM
Materials: All patients with GBM diagnosed between March 2008 and Nov
2010 undergoing concomitant treatment (radiotherapy 60Gy in 6 weeks withdaily temozolomide 75mg /m2) were reviewed retrospectively. Patients weremonitored at least weekly during treatment, which included a full blood countat each visit. If the platelet level fell to < 50% of baseline or to below 100,
treatment continued with radiotherapy alone. The PTV (cm3 ) for each patient
was measured directly from the radiotherapy planning system (Eclipse v8.6)
Results: 72 Patients were reviewed. 15 Had significant drop in platelets.
PTV volumes for these 15 patients ranged from 186.1-477.3cm3, with theaverage PTV of 279.12cm3. The average PTV for the remaining 57 patientswas 331.5cm3. There was no significant difference between these volumes.
Conclusions: There was no correlation between PTV and thrombocytopenia
in this group of patients who received concomitant treatment in our centre.
However, as a significant drop in platelets was observed in 20% of this groupwhich in many cases preceded more general haematoxicity it has endorsed
our weekly treatment review protocol which includes a FBC. It suggests further search for predictors of this phenomenon is necessary.
989 poster
TRAINING FOR A WORLD CLASS SERVICE: UK DOSIMETRISTEARLY IMPLEMENTATION PROGRAMME.
R. Lynn1 , M. Bidmead2
1
G UY ’ S AND ST T HOMAS ’ NHS T RUST, Medical Physics, London, United
Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Medical Physics,
London, United Kingdom

Purpose: Current advances in radiotherapy are dramatically improving theoutcome for patients with cancer. New applications of science underpin theseadvances, providing new opportunities for bright, committed individuals to become part of a world class scientific workforce in the National Health Service(NHS) within the United Kingdom. A national working group, however, identified a skills shortage amongst dosimetrists. In light of this, an early implementation dosimetrist training programme for science graduates has been fundedby the Department of Health’s (DH) National Cancer Action Team (NCAT). It
has been developed by the DH NCAT and the Modernising Scientific Careers(MSC) programme. The practical training has a strong emphasis on delivering new and emerging technologies within Radiotherapy and aims to broaden
the role of dosimetrists in the skill mix in Radiotherapy.
Materials: MSC has introduced a common training and career pathway for all
scientific staff within the NHS. At its heart are principles which seek to ensure
delivery of: patient safetystandards, quality and delivery of patient caretransparent workforce planning to develop a flexible, affordable and sustainable
workforcesecure and sustainable funding recognition for the unique contri-

S 373

bution of the scientific work force to research and innovation in the NHS A
multi-disciplinary steering committee, formulated from both clinical and nonclinical representatives across the UK from the MSC team, NHS London,
NCAT, the Institute of Physics & Engineerinq in Medicine (IPEM), the Society
and College of Radiographers (SCoR) and National Radiotherapy Implementation Group (NRIG), has worked closely alongside Heads of Radiotherapy
Physics departments in London to develop the workplace competencies, supported by a programme of academic learning.
Results: 11 trainees are now in post on a 2 year contract at 8 hospitals
within London. Assessment uses an online portfolio containing the workplacecompetenciesincluding: Dose planning and virtual simulation" Mould room"
Brachytherapy" Quality control of radiotherapy systems" Dose measurement"
Image guidance These are completed by the trainees, who determine when
and who will assess their competence and understanding during the 2 year
training period.Training sessions have been developed for their training supervisors, and cross-department mentoring will take place to maintain consistency of teaching standards, which will be overseen by IPEM.
Conclusions: An external evaluation of the programme will be carried out
to see if it meets the expectations and needs of the stakeholders. The first
results of the evaluation will be shared at the meeting. A ’toolkit’ is being
developed to assist in the roll-out of the scheme through out the UK, following
growing interest from other centres, keen for involvement as the lessons arebeing learned from this project.
990 poster
TREATMENT OF PATIENTS WITH PAEDIATRIC EWING SARCOMA(EWS). A SINGLE INSTITUTION EXPERIENCE
J. A. Nixon1 , I. Fragkandrea-Nixon2 , V. Sidi3 , D. Koliouskas3
1
F RIMLEY PARK H OSPITAL, Orthopaedic Department, Surrey , United
Kingdom
2
R OYAL M ARSDEN HOSPITAL, Neuro-Oncology, Sutton, United Kingdom
3
H IPPOKRATION H OSPITAL, Paediatric oncology, Thessaloniki, Greece
Purpose: Ewing sarcoma (EWS) is a rare, non differentiated, high grademalignant bone tumor. It belongs to the neuroectodermal tumor group, that
constitute a heterogeneous group of bone and soft tissue tumors. The aimof this study is to assess the clinical outcome of patients with EWS treatedwith the European Intergroup Cooperative Ewing Sarcoma Study (EICESS-92 and EURO EWING -99 ) protocols at a single center, during the period
1994-2009.
Materials: We included 19 pediatric patients with average age of 10,5 ( from
3 to 15) years, 12 male ( 63%) and 7 female ( 33%) who were treated according to the protocols EICESS -92 (11 patients) and EURO EWING 99( 8). In order to diagnose EWS for each child, demographic data, clinicallaboratory, imaging findings (CT or MRI of the primary site, thorax CT forlung metastases, Tc -99m bone scan for bone metastases) and bone marrow aspiration were evaluated. At the time of diagnosis, localized tumor wasobserved in 14 patients (73,6%), and metastatic disease in 5 patients (26,3%) (only lungs 2 ,combined or other sites 3). The most affected sites werefemur (7 patients 36,8%), distal lower extremity (6 patients 31,5%), pelvis(4 patients 21,04%) and rib (2 10,5%).The treatment plan included intensive
induction chemotherapy (EICESS -92 for 11 and EURO EWING 99 for 8 patients) consist of courses chemotherapy (Vincristine,Adriamicyn, Ifosfamide
and Etoposide), surgery, radiotherapy and finally consolidation with 8 courses
IVA (Ifosfamide,Vincristine, Dactinomycin).
Results: 12/19 patients are alive at 8,8 ( range 2 -15 ) years and 7 /19 diedfrom progressive disease(metastases or relapse). The 5 year overall survival(OS) was 63% and the 5 years eventfree survival (EFS) was 61,4%.
Conclusions: Results indicate that OS and EFS of children with Ewing sarcoma is in accordance with current international bibliographic data. Improved
EFS requires aggressive systemic chemotherapy, radiotherapy and surgery.
991 poster
TREATMENT OF PRIMARY LIVER CANCER USING HIGHLYCONFORMAL RADIOTHERAPY WITH KV-IMAGE GUIDANCE ANDRESPIRATORY CONTROL
W. T. Ng1 , A. Lee1
1
PAMELA YOUDE N ETHERSOLE E ASTERN H OSPITAL, 1st Clinical Oncology
Department, Hong Kong, Hong Kong (SAR) China

Purpose: Historically, the role of radiotherapy in hepatocellular carcinoma(HCC) was very limited due to the low radiation tolerance of liver. However,using advanced highly-conformal 3-dimensional radiotherapy, with imageguidance and respiratory gating technology, it is now possible to deliver a
sufficient level of radiation dose precisely to a highly-specific part of the liver,while sparing the surrounding normal liver tissue and other critical structures.
We report the preliminary treatment results of inoperable HCC using thishighly sophisticated technique in our centre.
Materials: Thirty-three patients with liver confined HCC were treated between May 2006 and Dec 2009. Radiotherapy was planned by conformal
techniques; and the treatment was delivered under respiration control andS 374PALLIATIONPALLIATION

image guidance using the Varian Real-time Position Management System
and On-Broad Imager respectively. The prescribed dose to the planning target volume was >50Gy over 10 fractions unless exceeding the normal tissue
dose constraints. The tumor response was evaluated on serial CT scans andalpha fetal protein (AFP) measurements every 3 months for the first year andthen annually.
Results: After a median follow up period of 16.5 months (3.5-40.7 months),
all but 2 patients demonstrated radiological tumor regression. Eight patients(24%) achieved complete remission. The median tumor shrinkage was 42%(27-100%). Subsequent in-field tumor progression was observed in only threepatients (10%). For the 23 patients with abnormal AFP level, 22 of themshowed biochemical response with a median AFP level drop of 78%. The
treatment was well tolerated. Grade 3 toxicities occurred in 5 patients (1 leucopenia, 1 elevated liver enzyme and 3 elevated bilirubin level) but there was
no grade 4 toxicity or treatment related death. The 1 year overall survival rate
is 71.7% and median survival time is 17.2 months (3.5-40.7 months). Qualityof life (QOL) data was collected on FACT-Hep in 29 (87.88%), 26 (78.79%),
19 (57.58%) and 12 (36.36%) patients at baseline, end of treatment, and at
3 and 6 months post-treatment respectively. The baseline FACT-Hep was
139.66, 133.56 at the end of the treatment (P = 0.26), 137.81 at 3 months (P= 0.55) and 130.00 at 6 months (P = 0.09). There was no statistically changein FACT-Hep score in all the time points when comparing with the initial.
Conclusions: Our encouraging result illustrates how technological advancesin radiotherapy have opened up a horizon in the treatment of inoperable HCC.
992 poster
TREATMENT PARAMETERS INCLUDING EUD FOR RE-RT OF
MALIGNANT GLIOMA
M. Niyazi1 , M. Söhn1 , U. Ganswindt1 , S. Schwarz1 , P. Lang1 , C. Belka1
1L.-M AXIMILIANS -U NIV., K L .
G ROSSHADERN, Radiation Oncology,
München, Germany

Results: A 4x4=16 cone demonstrator collimator has been build and evaluated. It confirmed the GEANT4 Monte Carlo simulations results of low scatterand a transparency of 28% at 1mm electron focal spot size. We achieved
about 80ms switching time between closed and open states for each cone
independently.
Conclusions: We demonstrate a method for ultrafast arbitrary 2D X-ray
beam shaping, which is one of the crucial components for achieving therapy
times in the low seconds range. Freezing patient motion during treatment
may become a viable alternative to motion adaptive treatments.

996 poster
994 poster

Purpose: Despite the given advances in neuro-oncology most patients withmalignant glioma ultimately fail locally or locoregionally. In this setting, reirradiation may serve as a reasonable treatment option. Although this treatment option has been widely adopted, data is lacking on treatment parameters concerning PTV coverage, re-irradiated volumes and dose deposition inorgans at risk (OAR).
Materials: Using the department database, 39 patients with a second courseof radiation were identified. GTV, PTV and relevant OAR (brainstem, optic chiasm, optic nerves, brain) were retrospectively analyzed. Relevant treatment
parameters were collected such as Dmax, Dmin, Dmean and volume [cc].
EUD values were calculated using TCP and NTCP models. Altogether approximately 1200 parameters were analyzed using descriptive statistics andunivariate analyses.
Results: Re-irradiation is a safe and feasible re-treatment option. Time interval between first and second irradiation was regularly above 6 months. EUDs
to the organs at risk were 11.9 Gy (range, 0.7, 27.4 Gy) to the optic chiasm,
17.6 Gy (range, 0.7, 43.0) to the brainstem, 4.9/2.1 Gy (range, 0.3, 24.5) tothe right/left optic nerve and 29.5 Gy (range, 25.5, 32.5) to the brain. No
correlation between treated volume and survival was seen. Cold spots anddose did not correlate with survival. Re-irradiated volumes were treated within average lower doses if they were larger and vice versa.
Conclusions: This study provides a guideline for possible normal tissue tolerances and determines the prognostic significance of different re-treated volumes. EUD values are derived and may serve as reference for further studies,including IMRT protocols.
993 poster
ULTRAFAST TWO-DIMENSIONAL MATRIX X-RAY COLLIMATORSO. Heid1 , T. Huges1 , T. Kluge1 , J. Heller1
1
S IEMENS AG, CTT P-HTC, Erlangen, Germany
Purpose: Patient motion during radiation treatment is becoming a dominantprecision limitation in IMRT X-ray treatments. Current motion adaptive treatment schemes have a number of specific problems and risks. Avoiding the
problem altogether by freezing motion requires treatment times of a few seconds instead of minutes as currently employed. Such a strategy necessitatesa significant redesign the treatment machine and therapy schemes. IMRT
dose delivery is based on a succession of a large number of independent arbitrary 2D beams, so breathhold treatments imply beam reshaping two ordersof magnitude faster than achievable with current leaf collimators.
Materials: We herewith present a novel ultrafast 2D matrix collimator (German patent 102008055921.0) which allows individual independent control of
32x32=1024 beamlets in less than 0.1 second. The design uses rotating
tungsten half cones (3) in front of a tungsten block with an array of conicalholes (4). This results in double focused collimation channels with the common focus (7) at the LINAC electron target. The cones are driven by electric
micro motors under real time computer control.

Purpose: Lung cancer is one of the most frequent causes of brain metastases in cancer patients, and radiotherapy the main treatment used in thesesituations. The survival of these patients after radiotherapy is not high, so thatits main goal is to improve their quality of life. Our objective was to evaluate
the survival time after application of radiation, to analyze the benefit of thistreatment
Materials: A total of 143 patients were treated with external beam radiation.
Of these, 134 were analyzed and 9 patients were eliminated from the study
due to lack of monitoring data. All of them were diagnosed with brain metastases from lung cancer. The treatment technique was external beam radiation applied on a holocraneal volume, with two opposed lateral fields and two
main types of fractionation: 3Gy/fraction in 10 fractions, (total dose = 30Gy);
4Gy/fraction in 5 fractions, (total dose = 20Gy)
Results: The distribution of cases according to pathology of primary lungtumor was: squamous 43 samples, adenocarcinoma 27, small cell 26, andother tumors 16. 23 had no definite pathological diagnosis. Median survival
was 4 months (range: 0-63 m), measured from the completion of radiation
therapy until the patient’s death or until his condition was considered terminal(premortem) and sent to home care unit. Survival between 0-3 months was
47.7% (64 patients); 3-6 months, 26% (35 patients); 6-12 months, 19.4% (26patients); and >12 months, 6.7 % (9 patients)
Conclusions: In our study survival after radiotherapy treatment in most patients with lung cancer and cerebral metastases is less than 6 months (around
73% of patients). After this work we consider it important to objectify clinicalcharacteristics and outcome of patients to establish criteria for treatment incertain patients whose survival is not only influenced after treatment with radiotherapy. These features could help to identify groups of patients for whombrain radiation treatment had no positive influence on survival and could be
avoided.

’NON-RHABDO SOFT TISSUE EXTREMITY SARCOMAS IN CHIDHOOD. 15 YEARS EXPERIENCE
I. Fragkandrea-Nixon1 , J. A. Nixon2 , V. Sidi3 , D. Koliouskas3
1

R OYAL M ARSDEN HOSPITAL, Neuro-Oncology, Sutton, United Kingdom
F RIMLEY PARK H OSPITAL, Orthopaedic Department, Surrey , United
Kingdom
3
H IPPOKRATION H OSPITAL, Paediatric oncology, Thessaloniki, Greece
2

Purpose: Sarcomas constitute 10% of childhood cancers. Major strides havebeen documented in the management of childhood sarcomas in the last two
decades leading to significant improvement in event free survival. This aretrospective study analyzing the overall survival in children with Non Rhabdo
Sarcomas of the extremities that have been treated in our institution over thelast 15 years.
Materials: From December 1994 to December 2009 (15 year period), 9 children patients with soft tissue sarcoma of the extremities, 5 boys and 4 girls,
mean age 8 years old, have been treated in our institution. We treated 3
cases of fibrosarcoma, 2 of liposarcoma, 2 of synovial sarcoma, 1 of alveolar
sarcoma and one of desmoplastic sarcoma. Two patients had lung metastases at diagnosis (1 with alveolar soft part sarcoma and 1 with desmoplastic
sarcoma). All children received multi modality management as per standardized protocols We audited, recorded and analyzed data regarding symptoms,investigations ,treatment administered and outcome of children patients withrare soft tissue sarcomas of the extremities.
Results: All children underwent induction chemotherapy followed by surgery.
Wide surgical excision was accomplished to 8/9 patients ,whereas one boy
with fibrosarcoma underwent amputation. Radiotherapy was offered to the2 patients with metastatic disease, as part of the protocol.Seven out of nine
(7/9) children are alive at a median of 96 (range 15 -170) months of follow up.
There were two deaths of progressive or metastatic disease (1 with fibrosarcoma and 1 boy with desmoplastic sarcoma)
Conclusions: Our data suggests improving trends in survival outcome in asingle institution. Radical surgical resection is the main& therapy for NonRhabdo Sarcomas in childhood, whereas multimodality treatment improves
survival and disease free survival.

Palliation
995 poster
BRAIN METASTASES IN LUNG CANCER PATIENTS: SURVIVALAFTER RADIOTHERAPY TREATMENT.
J. L. Monroy Anton1 , M. Soler Tortosa1 , M. Lopez-Munoz1 , A. V. Navarro
Bergadá1 , M. A. Estornell Gualde1
H OSPITAL U NIVERSITARIO DE LA R IBERA, Department of Radiation
Oncology, Alzira, Spain

1

EASYSIM: A PATIENT FRIENDLY VIRTUAL SIMULATION PROCEDURE FOR BONE METASTASES BASED ON DIAGNOSTIC IMAGING
A. Betgen1 , R. Haas1 , N. El-Mesbahe-Bouzeya1 , D. Minkema1 , M. Wolfrat1 ,C. Panneman1 , P. Remeijer1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
Purpose: Many cancer patients develop symptomatic skeletal metastases,
which may cause considerable morbidity such as pain, fractures, neurological complications and mortality. External beam radiotherapy (RT) plays animportant palliative role in the management of these patients. Conventional
simulators and CT based virtual simulation can be used to define irradiation
fields. In order to reduce the number of painful transfers from bed to simulator
and treatment couch and to reduce the total treatment time for the patient, wedeveloped a cone beam CT (CBCT) procedure which covers both simulationand treatment verification for bone metastases.
Materials: An application was developed to use a diagnostic CT, PET/CTor a MRI scan as a reference scan for the irradiation. In this application
an isocenter can be defined on this diagnostic scan, in combination with atreatment field. The treatment fields are standardized with a width of 10 cm
and a variable length of 7-20 cm at intervals of 0.5 cm. A standard treatmentplanning, prepared on a phantom, is added to these fields. Each treatment
plan is designed to deliver 1x8 Gy at a depth of 5 cm via a single PA field.
After selecting the isocenter and treatment field the plan is exported to thetreatment machine. At this treatment machine preparations for the irradiationand image guidance are performed (i.e. importing the data in the Record& Verification and image guidance systems). The patient is positioned on
the treatment couch and a CBCT is acquired. This CBCT is registered tothe diagnostic CT, PETCT or MRI scan. A couch shift is performed and asa second check an electronic portal image is acquired by administering 10
MU’s. The patient can then be irradiated.
Results: To date 23 patients were treated using this new application; all patients had metastases in the thoracic or lumbal vertebrae. In 9 patients a diagnostic CT-scan was used as a reference scan, in 5 patients a PET/CT andin 9 patients a MRI scan. The preparation time (without patient) was about
45 minutes, which includes preparation in the new application, treatment machine (Mosaiq) and the CBCT software (XVI). The total treatment time, which
includes the positioning of the patient, acquiring a CBCT, registration to thereference scan and irradiation, was on average 23 minutes (range 13 45)
Conclusions: We developed a procedure to treat patients with painful skeletal metastases using CBCT treatment verification. The entire procedure isquick, reliable and patient friendly.
997 poster
FRACTIONATED STEREOTACTIC RADIATION THERAPY VERSUSRADIOSURGERY IN BRAIN OLIGOMETASES: A LONG TERMANALYSES
R. Autorino1 , S. Chiesa2 , G. Chiloiro2 , G. R. D’Agostino2 , S. Manfrida2 ,A. Fiorentino2 , F. Micciche2 , G. C. Mattiucci2 , V. Frascino2 , C. Anile2 , V.

S 375

Valentini2 , M. Balducci2
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Department of Radiotherapy,
Roma, Italy
2
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Roma, Italy

1

Purpose: To aAnalyze the outcome of patients with brain oligometastases
treated by fractionated stereotactic radiotherapy (FSRT) or single dose Radiosurgery (SRS) after Whole Brain Radiotherapy (WBRT).
Materials: We retrospectively evaluated patients affected by 1-2 brain metastases, treated between January 1997 and May 2008, in our Institution, withFSRT (Group A) or Radiosurgery (Group B) plus WBRT.The two treatmentgroups were matched for the following potential prognostic factors: WBRT
schedule, age, gender, performance status, tumor type, number of brain
metastases, extracerebral metastases, recursive partioning analysis class(RPA).
Results: A Total of 47 patients were selected (25 M; 22 F) who were submitted to WBRT followed by FSRT (Group A, n: 30 pts) or Radiosurgery +WBRT (Group B, n: 17 pts). The median number of brain metastases was
1 (range 1-2) and median age of the patients was 57 (range 40-77 ys). No
statistical difference was found in the two groups in terms of age, histology,
number of brain metastasis, and RPA class. With a median follow-up of 102
months (range: 17-151), the median survival was 18,5 months for all patients,
with a median of 16 months for the SRT group and 22 months for the SRS
group. One-year and 5-year survival was 62,1% and 3% in Group A and 56%
and 16%, respectively, in Group B . Neither treatment proved to significative
impact on OS (p= 0,4).The 1-year local control rates were 61,1 and 80% respectively in two groups. No difference was observed in terms of brain control
between two groups (p= 0.15). Toxicity was acceptable in both groups, only
one patient (Group A) presented radionecrosis, radiologically demonstrated.
Conclusions: In our analysis seems that Radiosurgery or Fractionated
Stereotactic Radiation Therapy after WBRT could offer the same outcomesin patients with brain oligometasteses. Further investigation is warrented toconfirm these data and define the optimal dose/fractionation.
998 poster
PALLIATIVE RADIOTHERAPY IN PATIENTS WITH CANCER. REGIONAL CANCER INSTITUTE EXPERIENCE UNIT ALCAZAR DE
SAN JUAN (IMO.ASJ). CIUDAD REAL. SPAIN.
P. Sempere1 , J. L. Tisaire Sanchez2
1
I NSTITUTO O NCOLOGICO DE C ASTILLA L A M ANCHA, 2nd Radiation
Therapy Department, Alcazar de San Juan, Spain
2
GRUPO IMO, 2nd Radiation Therapy Department, Madrid, Spain
Purpose: Radiotherapy is a local treatment option used in 80% of cases palliative cancer, by frequency indications are pain, spinal cord compression syndrome, understanding tumor masses, bleeding, neurologic syndrome, brain
metastases and local recurrences primary tumors after definitive treatment
with curative intent, although surgery is could be a treatment option in thesecases, clinical conditions and locations of difficult surgical access, patient
morbidity, overall therapeutic option that difficult .The most common diseases
are: lung, breast, prostate, colorectal, head and necktreatment regimens aremost commonly used subdivisions of 30Gy in 10fracciones 3GY for almost all
locations, 50Gy in weekly 4Gy 4fracciones of 8Gy in single fraction for painfulbone injuries to spinal cord compression syndrome, and other schemes to
250Gy 25Gy/fr are also used.The main basis of palliative radiotherapy is toadminister the deposit of the highest possible dose to the tumor with the greatest protection in healthy tissues nearby, this goal is more accurate due to advances in technology allowing to obtain data quantifying the dose received
reducing the uncertainties both clinical and technical setting new challenges
and treatment alternatives to clinical situations not previously possible. The
development of radiotherapy in the collection, handling, image processing,planning systems more precise, versatile and medical physicists, results ofclinical and applied research have allowed the indication for palliative radiotherapy has also been developed. The level of evidence in palliative radiotherapy is 1As NCCN category. The National Cancer Center, for specific casessuch as spinal cord compression syndrome, brain metastasis.Whereas radiotherapy unit Alcazar de San Juan is coordinated with the Hospital La Mancha
Centro Ciudad Real, with a year of activities together. The following paper
aims to describe the distribution of indications in palliative radiotherapy incancer patients have been treated in the Radiotherapy Unit of Alcazar de
San Juan from November 2008 to February 2010.
Materials: The following work is descriptive, retrospective study included all
patients admitted for palliative radiotherapy from November 2008 to February2010 using the criteria of HLM-IMASJ medical group. Ciudad Real. Spain,
protocols of the Treaty 6mV Elect Accelerator. The factors that were considered: sex, age, indication for palliative radiotherapy, to describe the distribution and location of primary tumor metastasis, bone lesions, soft tissue mass
associated fractionation scheme according to pathology.
Results: 104 patients were treated between November 2008 to February2010 using the criteria of HLM-IMASJ medical group. Ciudad Real. Spain,with an indication for palliative radiotherapy for symptomatic metastatic disease. The average age was 78 th (40 th -88 th), males (59%) and female (41%) primary tumors were the most frequent metastatic non-small cell

S 376PALLIATIONPALLIATION(PNCP) 20%, breast 9%, colorectal 7 %, prostate 6%, other (10%) and 2%
kidney, bladder, 2%, multiple myeloma, 2%, 2% vagina. Holocraneo indication of brain metastasis was 36% for PNCP was the most frequent (45%)
and the indication for bone metastases was 53%, and breast (40%), prostate(30%) and soft tissue (lymph nodes ) 16%. In bone metastases, dorso-lumbar
spine was the most frequent (77%), spinal cord compression syndrome waspresent in 30%, without soft tissue mass (31%) and soft tissue mass (69%) .
Fractionation schemes for the treatment of 3x10fracciones was used in 98%
of holocraneo and 2.5x10/15f (2%) in bone lesions: In column: 3x10fr (82%),
2.5x10/15fr (15%) , 4x5fr (9%), fr 2x21 (1%).
Conclusions: The indication for palliative radiation therapy more frequentin HLM-IMASJ. Were the brain and bone metastases. Bone lesions dorsal
lumbar spine with associated soft tissue mass and spinal cord compression
syndrome is the most common. The 3x10fr fractionation scheme is the mostwidely used to treat bone injuries and strokes.
999 poster

exposure. Majority of the patients who were on pain killers showed a significant reduction in pain after SPMF exposure. Many patients after the SPMF
exposure returned to their routine daily activities. 5 of the 57 brain tumour
patients were lost to follow up. The survival record of 52 patients, revealed
the following: 15.3% of patients survived for 12 months 5.76% of patientssurvived for 24 months 7.69% of patients are still alive for the past 48 months
Conclusions: These findings not only herald a new strategy for palliative
care of cancer but also suggest that it has the potential to improve the qualityof life of cancer patients in terminal stages and furthermore, to be used as
first line of treatment for brain tumours in future.
1001 poster
SPINAL RADIOSURGERY – EFFICACY AND SAFETY AFTER PRIORCONVENTIONAL RADIOTHERAPY
K. Nikolajek1 , M. Kufeld2 , A. Muacevic2 , B. Wowra2 , M. Niyazi1 , U.
Ganswindt1
L.-M AXIMILIANS -U NIV., K L .
G ROSSHADERN, Radiation Oncology,
München, Germany
2
E UROPÄISCHES C YBERKNIFE Z ENTRUM M ÜNCHEN G ROSSHADERN,
Munich, Germany
1

PALLIATIVE RADIOTHERAPY USE OF LA MANCHA IN THE HOSPITAL CENTER
P. Sempere1 , J. L. Tisaire Sanchez2
1
I NSTITUTO O NCOLOGICO DE C ASTILLA L A M ANCHA, Alcazar de San Juan,
Spain
2
GRUPO IMO, Madrid, Spain
Purpose: The Hospital General La Mancha Centro, attending a healtharea of 180,000 people, with a concerted Radiotherapy Unit of the IMOGroup.Palliative radiotherapy is an important component of multidisciplinary
treatment of cancer. Its aim is to control symptoms caused by tumor or metastases. Different publications estimate that between 28-54% of treatments
are used for palliative radiotherapy, depending on the availability of this resource.The aim of this study is to analyze the distribution and characteristics
of patients referred for palliative radiotherapy in the area TheMancha Centro.
Materials: We prospectively collected data on the use of radiotherapy withpalliative (symptom control) in the Unit of Alcazar de San Juan, during theperiod of 12 months (January-December 2009).
Results: Of the 257 patients treated in this period, 76 (29.5%) were referred
for palliative treatment, 15% required more than one treatment for new locations. The mean age was 61 years (R :29-88), 56% men.Location ofprimary tumor: lung 40.8%, breast 17.1%, prostate 13.1%, 7.9% Colorectal, ENT 3.9%, and other types in 17.1%.Locations of metastasis: 34.2%
brain, spine 30.2%, bone 19.7%, primary tumor or regional lymph node area
in 31.5%.58% of patients with lung cancer were referred for brain metastases and 46% ofpatients with ca. vertebral metastasis breast.Fractionation
schemes used: 10x300 cGy in 51%, 15x250 cGy: 19%, 5x400 cGy: 12.55,
17.5% other schemes.Total dose: 20 - 66 Gy (median 30 Gy).
Conclusions: In our unit, almost 30% of the welfare activity is devoted to palliative radiotherapy.The development and implementation of forecasting algorithms allow the individualization of treatment and optimization of resources
1000 poster
SEQUENTIALLY PROGRAMMED MAGNETIC FIELD (SPMF) THERAPY IN THE MANAGEMENT OF ADVANCED STAGES OF CANCER(TERMINALLY ILL)
V. Vasishta1
1
I NSTITUTE OF A EROSPACE M EDICINE , I NDIAN A IR F ORCE, Radiodiagnosis,
Bangalore, India
Purpose: Sequentially Programmed Magnetic Field (SPMF) technology involves use of programmed magnetic fields, generated from Magnetic Field
Generators (MFG) which can be focussed onto the target tissue, based on its
proton density, in a precisely controlled manner. These are non-thermal, nonionizing and has no known side effects. Dealing with cancer has become oneof the challenges of the day; concurrently giving a tough time to scientists
trying to develop an effective treatment for the deadly disease. Some cancers when detected and treated at an early stage have found to be reactive
but those at an advanced stage do not respond to most of the anti-cancerous
drugs. Even if there is a response, one has to undergo a lot of anguish because of the side effects of the treatment rather than the disease itself. There
was always a need for a treatment without any side effects.
Materials: 143 patients with terminally ill cancer of all major organs wereenrolled for the study. 57 of the 143 patients were with malignant tumours
having completed all standard treatment and had come with recurrence. All
patients had enrolled for the study on a voluntary basis. The patients were
exposed to SPMF Therapy daily for 1 hr, for 28 consecutive days and wereassessed using the Karnofsky Performance scale scores before and after
exposure. 85 of the 143 patients were also assessed by FACT scores.
Results: The assessment of 143 patients with terminally ill cancer patients
revealed a statistically significant (p value < 0.001) correlation between KPS
Score improvement and SPMF therapy exposure. 85 of the 143 patients who
were also assessed for FACT-GP Scores, across treatments, showed significant correlation (p< 0.0001) between FACT-GP Score and SPMF Therapy

Purpose: Conventional external beam radiotherapy is a standard procedure
for treatment of spinal metastases. In case of progression spinal cord tolerance limits further radiotherapy in pre-irradiated areas. Spinal stereotactic
radiosurgery (SRS) is a non-invasive option to re-treat pre-irradiated patients.
Nevertheless, SRS results in relevant dose deposition within the myelon withpotential toxicity. Aim of the study was to retrospectively analyze the efficacy
and safety for salvage SRS of spinal metastases.
Materials: During a period of 4 years 70 lesions in 54 patients were analyzed. Clinical and radiological follow-up was collected prospectively afterradiosurgery. Pain as a main symptom was classified by Visual Analogue
Scale (VAS) score. Every patient received single session SRS after having
been treated first-line with conventional radiotherapy. Kaplan-Meier method
and life tables were used to analyze freedom from local failure and overall
survival.
Results: The actuarial rates of freedom from local failure at 6/12/18 months
were 95%/93%/83%. The VAS score of patients with pain (median 6) dropped
significantly (median 4, p=0.002). One patient developed a progressive paraparesis one year after the last treatment at lumbar level L3. Due to multiple
treatments and further local progression, the exact reason remained unclear.
Apart from that, no CTC grade III or higher toxicity has been observed.
Conclusions: By applying SRS relevant radiation doses can be limited tosmall parts of the myelon. This seems to prevent for myelopathic side effects
and makes it an efficient and safe treatment option.
1002 poster
STEREOTACTIC RADIOTHERAPY ALONE IN BRAIN METASTASES:ANALYSIS OF 279 PATIENTS.
E. Maranzano1 , F. Trippa1 , P. Anselmo1 , S. Carletti2 , M. Principi3 , F. Loreti4 ,M. Italiani5 , M. Casale6 , R. Rossi6 , C. Giorgi7
1
R ADIOTHERAPY C ENTRE, Department of Oncology, Terni, Italy
2
N EUROSURGERY C ENTRE, Department of Neurology, Terni, Italy
3
N EURORADIOLOGY C ENTRE, Department of Radiology, Terni, Italy
4
N UCLEAR M EDICINE S ERVICE, Department of Radiology, Terni, Italy
5
O SPEDALE S ANTA M ARIA, Department of Oncology, Terni, Italy
6
O SPEDALE S ANTA M ARIA, Terni, Italy
7
N EUROSURGERY C ONSULTANT, Terni, Italy
Purpose: We report our experience with radiosurgery (SRS) or fractionatedstereotactic radiotherapy (FSRT) performed with 5-MV linear accelerator fitted with a commercial dynamic micromultileaf collimator, in the treatment ofpatients (pts) with brain metastases (BM).
Materials: Between September 2001 and October 2008, 279 pts with 434
BM were treated with stereotactic radiotherapy (SRS or FSRT) without wholebrain radiotherapy (WBRT). Male/female ratio was 163/116, median age was
63 years (range, 22-86), and WHO performance status (PS) ranged between
60 and 100 (median 90). Most common tumour histologies were: non small
cell lung cancer 53%, breast 14%, kidney 9%, melanoma 7%, colorectal 4%,other tumours 12% and unknown primary 1%. The 54% of pts had a controlled primary tumour while remaining 46% had local or systemic progression of disease. Median neurological functional score and recursive partitioning analysis class were 0 (range 0-4) and 2 (range, 1-3), respectively. Score
index for radiosurgery ranged from 2 to 10. Four hundred lesions (92%) weretreated with SRS, and remaining 34 (8%) with FSRT. The overall average
number of lesions treated per patient was 1 (range, 1-4), with an averagecross-sectional diameter of 13 mm for SRS and 32 mm for FSRT. The volume
ranged from 0.1 to 25 cc (median 1.2) and from 0.3 to 79.9 (median 18) in
SRS and FSRT, respectively. The median dose was 23 Gy (range, 12-25) in
SRS, while FSRT pts received 10 x 3Gy, 5 x 6 Gy, 5 x 7 Gy, or 6 x 5 Gy in
13, 4, 10, and 7 lesions, respectively. Dose was prescribed at isocentre, withminimum accepted dose of at least 90%. Patients were seen for follow-up 4

weeks after the end of stereotactic radiotherapy, then in 3-month intervals or
as needed. During follow-up, magnetic resonance imaging (MRI) was madeevery 3 months or when clinical worsening developed. Local control was defined when the BM irradiated not showed a progression.
Results: Response was evaluable in 264 of 279 (94%) pts with a total of 407
metastases receiving MRI evaluation. Duration of response and survival wereassessed in 245 (88%) patients because 34 (12 %) pts were lost to follow up.
Median follow-up was 67 months (range, 24-110). Local control was obtainedin 94% of the lesions, according to the following response rates: complete
remission 95 (23%), partial remission 146 (35%), stable 142 (35%) and progression in 24 (6%) metastases. There were 187 (46%) brain relapses: 26(7%) "in-field", 136 (33%) "out-field" and 25 (6%) both "in-field" and "out-field".
Salvage treatment was administered in 52 (21%) pts, 27 (52%) of which received SRS, 4 (8%) FSRT, 18 (34%) WBRT, 1 (2%) surgery followed by WBRTand 2 (4%) SRS followed by WBRT.
Conclusions: Our results showed that pts with 1-4 BM, good PS and life
expectancy more than 3 months could be treated only with SRS or FSRT
avoiding WBRT. This approach may be done on condition that patients arecarefully selected by MRI.
1003 poster
STEREOTACTIC RADIOTHERAPY FOR THE TREATMENT OF BRAINMETASTASES
A. Papaleo1 , D. Russo1 , P. Adriana2 , P. Cantisani3 , C. D. Gianfreda3 , C.

S 377

treatment and 13 lesions were treated with whole-brain radiotherapy plus a
HSRT boost. The macroscopic (gross) tumor volume (GTV) was drawn on
the MRI images. The dosimetric planning was performed with the Corvus
Inverse Planning System. The prescription isodose line was generally 1 to 2
mm larger than the GTV to account for fixation inaccuracy. The prescribed
dose was 30 Gy with 5 fractions to a median 98% isodose line (range, 95%100%). Patients received treatment daily on consecutive days. The maximum
dose to the optic apparatus was limited to 20 Gy in 5 fractions and that tothe brainstem was limited to 25 Gy in 5 fractions. The treatment volume ratio(TVR) was defined as the total volume receiving the prescription dose divided
bythe tumor lesion volume. The TVR was calculated for relative comparison
between plans as a measure of the conformality of the dose distribution to
the tumor lesion volume. Patients were seen at least 4 weeks after HSRT
and were evaluated with MRI and a physical examination. Each lesion wasmeasured for local tumor response and graded using the criteria of MacDonald et al with the following categories: 1) complete remission (CR) indicatedthe disappearance of all enhancing lesions on MRI, 2) partial remission (PR)indicated evidence of a >50% reduction in the cross-sectional dimension of
the tumor on MRI, 3) progressive disease (PD) indicated a >25% increase insize, and 4) stable disease (SD) indicated all other responses. Any significant increase in tumor size (>25%) in the interval was defined as local tumor
control failure and the appearance of any new lesion was considered to be an
overall brain tumor control failure. Any toxicity (defined as an adverse event)
was recorded according to the RTOG.
Results:

Accettura4 , M. Santantonio1
1
O SPEDALE V ITO FAZZI, Department of Radiation Oncology, Lecce, Italy
2
O SPEDALE V ITO FAZZI, Department of Neuro-Radiology, Lecce, Italy
3
O SPEDALE V ITO FAZZI, Department of Neurosurgery, Lecce, Italy
4
O SPEDALE V ITO FAZZI, Department of Clinical Oncology, Lecce, Italy
Purpose: Patients with brain metastases are traditionally treated withsurgery, whole-brain radiotherapy(WBRT), or stereotactic radiosurgery(SRS). In the past decade, the use of SRS in the treatment of brain metastases has grown considerably. Recent studies have revealed an overall survival advantage with the incorporation of SRS after WBRT. SRS is typicallydelivered in a single fraction using an invasive head frame. Although theframe provides accurate localization and minimizes motion, patients are often reluctant to undergo standard head frame placement because of pain andgeneral discomfort. Because of the radiobiologic advantage of fractionatedtreatment on sensitive structures in the brain, radiosurgery systems were developed with relocatable head frames to allow for stereotactic delivery overmultiple fractions without the need for repeated invasive head frame applications. Such fractionated approaches have been found to provide accuracy
equivalent to that of single-fraction SRS, while providing protection for eloquent structures through fractionation. This retrospective review evaluatedthe efficacy and toxicity profiles of hypofractionated stereotactic radiotherapy (HSRT) with Talon, an relocatable head frames in the treatment of brain
metastases.

Materials: Between November 2008 and November 2010, 37 patients with
1-4 brain metastases were treated with HSRT at the Department of Radiation
Oncology at V. Fazzi Hospital. In total, 63 brain metastases were treated with
HSRT. Of these 63 lesions, 50 lesions were treated with HSRT as the primary

The median follow-up interval was 12 months (range, 2 months- 20 months).
The median maximum tumor dimension, treatment volume, and TVR were
11.6 mm (range1.7 mm-31.2 mm), 0.52 cc (range, 0.05 cc-15.41 cc), and3.4 (range, 1.7-24.0), respectively.The median overall survival time was 10.8
months, and 66.7% of patients died of disease progression. After HSRT treatment of 63 brain lesions, 30 lesions demonstrated complete responses, 15
lesions demonstrated partial responses, 15 lesions demonstrated stable disease, and 3 lesions demonstrated progressive disease. Actuarial local tumor
control rates at 6 months and 1 year were 93.9% and 68.2%, respectively.
Maximum tumor dimension and a tumor volume <1 cc were found to be statistically significant factors for local tumor control. Twentynine patients did nothave any adverse events >grade1. The majority of common adverse eventswere grade 2 headaches (reported in 4 patients; 15%), grade 2 motor neuropathy (reported in 2 patients; 7,6%), and grade 2 lethargy (reported in 1
patient; 3,8%). One patient (3.8%) developed a grade 3 headache 5 months
after receiving HSRT.
Conclusions: HSRT provides a high level of tumor control with minimal toxicity. The results of this retrospective study demonstrate that HSRT is a very
effective and safe treatment approach that is comparable to SRS at controlling brain metastases. The results of our study are similar to those of previous
single-fraction SRS studies. Compared with WBRT plus SRS as used in the
RTOG 9508 trial (which reported local control rates of 82% and 71%, respectively, at 3 months and 1 year), the local tumor control rates producedby HSRT in the current series were comparable.Previous investigators havedemonstrated that maximum tumor dimension (in mm) and volume (in cc) are
prognostic factors for local tumor control and toxicity. We found similar resultsin the current study and there was a significant difference in the local tumor
control rates among the treatment groups when segregated by maximum tumor dimension (≤ 20 mm vs >20 mm and ≤ 30 mm vs >30 mm; P = .033).
Tumors measuring ≤ 20 mm were found to have better actuarial local control
rates at 1 year than tumors measuring >20 mm (81.5% vs 37.5%). With regard to tumor volume, patients with a tumor volume ≤ 1.0 cc were found tohave a better tumor control rate (P = .028). Actuarial local tumor control rates
for tumors with volumes ≤ 1.0 cc and >1.0 cc at 6 months were 100% and87.5%, respectively. Furthermore, local control rates for tumors with volumesof ≤ 1.0 cc and >1.0 cc at 1 year were 100% and 46.7%, respectively. Thisfinding also may be closely supported by the discovery that even the treatment group with tumor volumes ≤ 2.0 cc had a better chance of achieving
local tumor control than those with tumor volumes >2.0 cc (P =.068). Future studies including a larger number of patients and close follow-up will beneeded to understand this issue better Therefore, we believe there is a needfor a larger prospective study to establish dosing guidelines for HSRT and topave the way for a randomized trial to compare single-fraction SRS with ahypofractionated approach.

S 378P ROSTATE CANCERP ROSTATE CANCER

1004 poster
TOMODIRECT: AN EFFICIENT MEAN TO DELIVER PALLIATIVERADIOTHERAPY WITH DISCRETE ANGLES TOMOTHERAPY FORSKELETAL METASTASES
P. Franco1 , P. Sciacero1 , P. Catuzzo2 , D. Cante1 , G. Girelli1 , V. CasanovaBorca2 , M. Pasquino2 , S. Tofani2 , M. R. La Porta1 , F. Zenone2 , U. Ricardi3 ,F. Ozzello1
1
O SPEDALE R EGIONALE ’U. PARINI ", Radiation Oncology, Aosta, Italy
2
O SPEDALE R EGIONALE ’U. PARINI ", Medical Physics, Aosta, Italy
3
U NIVERISTY OF TORINO - S. G IOVANNI B ATTISTA H OSPITAL, Radiation
Oncology, Torino, Italy
Purpose: Radiation therapy is one of most effective agent to palliate painrelated symptoms for skeletal metastases in oncological patients. In this context, hypofractionated schedules are employed and often simple and rapid
radiation techniques are used .Recently, the TomoTherapy Hi-Art II system(TomoTherapy Inc,. Madison, WI) has introduced an upgrade of the commercially available platform named TomoDirectTM adding the possibility to deliverradiation at discrete angles with Tomotherapy. The system allows for thedelivery of fast and effective radiotherapy to the affected bones. We hereinpresent our preliminary clinical experience with TomoDirect in the clinical context of skeletal metastasis. To our knowledge this is the first report concerning
this issue.
Materials: Between May and November 2010 a total of 25 metastatic skeletal
lesions (20 patients) has been treated with TomoDirect at our Institution Hospital. Mainly vertebral metastasis have been treated (70%); the other 30% of
the lesions were located within long bones or pelvic bones. Main primary site
was lung. After planning CT acquisition and volumes contouring, DICOM-RT
images were exported to the TomoTherapy HiArt treatment planning system
v4.0, where TomoDirectTM plans were generated. Patients were prescribed
different radiation schedules according to the appropriate clinical context (30Gy/10 fr; 20 Gy/5 fr; 8 Gy/1 fr). The 90% percentage PTV volume should becovered at least by 95% of the prescribed dose.
Results: All patients completed the planned radiotherapy program with nointerruptions. Different fields arrangement were employed according to thecharacteristics of the anatomical sites (2 fields mimicking a single one or
multiple fields). Brief Pain Inventory form were obtained from any patientat the end of the treatment and at 2 months follow up. No acute toxicity wasrecorded. The median self-reported worst pain decreased significantly; 63%of the patients reported pain relief.
Conclusions: TomoDirect has demonstrated to be a feasible and efficientmean to deliver palliative radiation to relief bone pain for skeletal metastasis. Acceptable dose distribution, negligible toxicity, limited set up time andtreatment room occupancy time have been detected.

Prostate cancer
1006 poster
A NOMOGRAM TO PREDICT THE NUMBER OF I-125 SEEDS AND
NEEDLES FOR PROSTATE BRACHYTHERAPY
H. Mosalaei1 , C. Lewis1 , M. Mulligan1 , N. Patil2 , D. D’Souza2
1
L ONDON R EGIONAL C ANCER P ROGRAM /LHSC, Department of Medical
Physics and Radiation Safety, London, Canada
2
L ONDON R EGIONAL C ANCER P ROGRAM /LHSC, Radiation Oncology,
London, Canada
Purpose: Intraoperative adaptive planning for low dose rate (LDR) prostatebrachytherapy requires ordering appropriate number of iodine (I-125) seeds
and needles. The total activity required to deliver the prescribed dose is predicted by nomograms based on the prostate volume. The total activity is used
not only for ordering the seeds but more importantly, it is used to estimate thenumber of seeds to be implanted peripherally (75%) and internally (25%). After peripheral seeds are implanted, the internal seeds are added to achieve
optimum dosimetry. However, overestimation of total activity results in too
many seeds implanted peripherally, which is difficult to correct for with internal needles, especially for small prostates. This can result in a high urethral
dose. At our center we used two different nomograms1, 2 and both over estimated total activity, in particular for prostates smaller than 30cc. The purposeof this study was to design a nomogram that predicts the number of seeds
and needles based on the prostate size.
Materials: Data from patients with I-125 seed prostate implants at our center
between 1998 and 2010 have been analyzed. We used prostate volumes,
which ranged from 11.8 to 59.8 cc with an average of 32.29 cc to predict total
activity, max width and height to predict the number of peripheral needles,
and the length to predict the number of seeds per needles.
Results: Using developed nomogram, we could predict the number of seeds
more accurately to prevent excess number of seeds implanted peripherally
and reduce the number of leftover seeds to 3-4% of the total number of seeds.
This results in good peripheral dose coverage with an acceptable urethraldose less than 130% of the prescribed dose.
Conclusions: The total activity required to deliver the prescribed dose to thetarget volume can be predicted without over estimation. This could result inbetter dosimetry and reduce the overall cost of treatment by accurate prediction of the number of seeds before implant.
1. Variseed program version 8.0, Varian Medical Systems
2. Al-Qaisieh B, Brearley E, St Clair S, Flynn A. "A study of a pretreatment method to predict the number of I-125 seeds required for prostatebrachytherapy" Int J Radiat Oncol Biol Phys. 2006 May 1;65(1):304-71005 poster
TWO PROGNOSTIC INDEXES RPA AND GPA IN BRAIN METASTASIS: THE CROB/IRCCS EXPERIENCE.
A. M. Mileo1 , A. Fiorentino1 , C. Chiumento1 , R. Caivano1 , M. Cozzolino1 ,V. Fusco1
1
IRCCS CROB, Department of Radiation Oncology, Rionero in Vulture,
Italy
Purpose: To evaluate Overall Survival (OS) in patients (pts) with brain metastases (BMs) treated with External Beam Radiotherapy (EBRT), according to
the two prognostic index: Recursive Partitioning Analysis (RPA) and Graded
Prognostic Assessment (GPA) .To evaluate Overall Survival (OS) in patients(pts) with brain metastases (BMs) treated with External Beam Radiotherapy(EBRT), according to the two prognostic index: Recursive Partitioning Analysis (RPA) and Graded Prognostic Assessment (GPA) .
Materials: Patients aged ≥18 yrs with diagnosis of BMs and treated in ourRadiotherapy Departement ,were retrospectively evaluated .Patients underwent to 3D Whole Brain Radiation Therapy based on conventional computer
tomography with 2 opposite field and a total dose of 30 Gy/300cGy die or
20 Gy/400cGy die.Pts were stratified by: RPA and GPA class. Overall Survival (OS) was calculated from the diagnosis of BMs to death or last followup.SPSS v 13 (Palo Alto ,USA) was used for statistically analysis.
Results: From October 2005 to March 2009, 53 patients (pts) were treated:25
pts were female and 28 male, the median age was 64 years (range: 36 -80
yrs). Sixteen pts received 30 Gy and 37 pts 20Gy.After a median follow-up of
14 months (range 9-62 mo), median OS was 6 months with 1 and 3yrs OS of
25 and 11%.When stratified patients on RPA and GPA class no significantly
differences were found on outcome ( p0.3 and p0.2 respectively ). This results
depend from small sample size.
Conclusions: More studies are mandatory to confirm the greatest prognostic
power.

1007 poster
ACUTE TOXICITY OF FORWARD PLANNED SIMULTANEOUS
INTEGRATED BOOST IMRT IN PROSTATE PATIENTS TREATED
WITH 76GY IN 37#
H. B. Musunuru1
1
S T. JAMES ’ S INSTITUTE OF ONCOLOGY, Clinical Oncology, Leeds, United
Kingdom
Purpose: Following publication of NICE guidance (2008), the radical radiotherapy protocol for non-metastatic prostate cancer(PC) at St. James’s Institute of Oncology, Leeds was changed to 76Gy in 37 fractions(#). A single
phase field in field IMRT technique (4 beam arrangement) is used. The 95%
isodose encompasses the GTV (prostate +/- SV). The PTV = GTV with a
10mm isotropic margin (8mm posteriorly) and is encompassed by the 86%
isodose.
Materials: 105 consecutive patients were treated from February to August
2009. Information was collected prospectively with toxicity assessed 6 weeks
from completion of treatment using RTOG GU and GI toxicity scores. Data
related to age, PSA, Gleason score, risk group, neoadjuvant hormones, comorbidities, mean rectum diameter at superior, mid and inferior PTV slices,
DVH for rectum and bladder, acute GI and GU toxicities was collected for the
first 105 patients treated within the new protocol.Data was analysed using
one way ANOVA to compare means and chi-square to compare percentages.
Results: All patients completed radiotherapy.
1. Mean age 69 (range 54-79) yrs, mean PSA 10.9 (range 1.5-79.5)
ng/ml, median Gleason score 7 (range 6-9).
2. 12, 31, and 57 % were in low, intermediate, and high NCCN risk groups
respectively.
3. 92 patients (87.6%) were started on neo adjuvant hormones (either
short term or long term).
4. Acute toxicity was assessed at 6 weeks post treatment. 54 (55%),
37(38%) and 7(7%) patients had grade 0, 1 and 2 GU toxicities respectively.

5. 68 (70%), 24 (25%), 5 (5%) patients had grade 0 ,1 and 2 GI toxicities respectively. One patient had large rectal bleed needing bloodtransfusion (grade 3 GI toxicity).
6. DVH statistics have shown that mean % of bladder receiving >74Gy
is 0.16 ,0.17, 0.17 and >67Gy is 10.5, 10.8 and 7.7 for patients withgrade 0 ,1 and 2 GU toxicities.
7. Mean% of rectum receiving >74Gy is 0.1 , 0.4, 0.09 and 0, >70Gy is
8, 7, 12, 13, >67Gy is 17 ,16, 23, 24, >55.5Gy is 33 ,32, 41, 42 forpatients with grade 0, 1, 2, 3 GI toxicities respectively.
8. The mean anteroposterior rectal diameter (cm) at superior, isocentricand inferior PTV slices is 2.79, 3.3, 3.0 respectively for patients withgrade 0 GI toxicity, 2.7,3.3,2.8cm for grade 1, 2.8,3.5,2,5 cm for grade
2 and 3.1,3.2,2.7 cm for patients with grade 3 GI toxicity.
9. There was no significant difference in planning scan rectal diameter
between patient toxicity groups.
% of rectum receiving (X) dose in patients with grade 0,1,2,3 GI toxicities.

Conclusions: Radical radiotherapy for Prostate cancer at a dose of 76Gy
in 37 fractions was well tolerated. The increase in the volume of rectum receiving >70Gy, >67Gy and >55.5Gy might be associated with increased GI
toxicity.
1008 poster
CAN ANTI-ANDROGENIC THERAPY INDUCE ADIPOSE TISSUE
CHANGES IN PROSTATE CANCER PATIENTS? AN EXPLORATORYANALYSIS.
A. Martos1 , S. Sabater1 , E. Jimenez1 , M. V. Carrizo1 , R. Berenguer2 , I.
Andres1 , M. Sevillano Capellan1 , M. Aguayo Martos1 , M. Rivera2 , A. T.
Núñez2 , V. de la Vara Olivas3 , M. V. Villas1 , M. Arenas Prat4
1
H OSPITAL G ENERAL DE A LBACETE, Department of Radiotherapy, Albacete,Spain
2
H OSPITAL G ENERAL DE A LBACETE, Department of Medical Physics,
Albacete, Spain
3
C OMPLEJO H OSPITALARIO A LBACETE (CHUA), Department of Medical
Physics, Albacete, Spain
4
H OSPITAL S ANT J OAN DE R EUS, Department of Radiotherapy, Tarragona,
Spain
Purpose: Hypognadism is a well known factor related to the adipose tissue
increase, cardiovascular risk and skeletal myopathy. Quantitative CT scans
have shown a fat redistribution and a decrease in bone density secondary tohypogonadism. Androgenic blockade (AB) induces an hypogonadism status
and thus prostate cancer patients are expected to show a fat redistribution on
CT scans. The aim of our study was to quantify throughout time, with serial
CT, fat and loan changes related to this induced status.
Materials: CT scans from 17 prostate cancer patients treated with androgenic blockade were reviewed. CT sets were analyzed with the MIPAV software, developed by the Center for Information Technology (v.4.4.1, U.S. National Institutes of Health) using the abdomen segmentation plugin and thegrow region tool. Fat and loan areas and mean Hounsfield units (HU) wererecorded from abdominal total, subcutaneous and visceral fat tissue, as wellas waist and hip circumferences. To quantify tissues the next thresholds weretaken into account: fat pixels -190/-30; muscle pixels 0 / 100. Patients hada basal CT scan and another study acquired 6, 12, 18 or 24 month later.
Nonparametric paired statistics were used.
Results: 8 men underwent a long term androgenic blockade, for another8 patients it lasted 9 month or less, and one patient didn’t receive antiandrogens. To improve statistics 6 and 12 CT studies results were grouped,
the same was done for the 18-24 CT studies. Mean abdominal area significantly increased 6-12 month after the start of AB (871.24 vs 946.56 cm2 )that couldn’t reach significance at 18-24 month, but lean abdominal area

S 379

significantly decreased at this time (mean 202.92 vs 79.97 cm2 ). Visceralarea increased significantly at 6-12 month compared to basal scan (422.61
vs 394.36 cm2 ), but no differences were seen when comparing fat and loan
visceral area.
Conclusions: Hypogonadism has been related to an adipose redistribution,
our results have demonstrate also a fat redistribution, but the small size ofthe sample and the short interval after the AB start has prevented to obtaina complete statistical significance for all the analyzed variables. So we areplanning to evaluate a large sample of patients.
1009 poster
CLINICAL USE OF FIDUCIAL MARKER MATCHING AND CBCT
REVIEW FOR PROSTATE AND PELVIC NODE IMRT
M. Vilarino-Varela1 , D. Eaton1 , J. McCaffrey1 , K. Pigott1
1
R OYAL F REE H AMPSTEAD NHS T RUST, Radiotherapy, London, United
Kingdom
Purpose: The use of fiducial markers allows accurate localisation of theprostate target volume in radiotherapy, which can move substantially compared to bony anatomy. However, when also treating the pelvic nodes, a decision based solely on the marker matching could lead to a geographic missof the nodal volume. Therefore a hybrid correction protocol was developedin our centre and CBCTs used to assess volume coverage online, and DVH
tolerances offline in the treatment planning system.
Materials: From June 2009 to November 2010, 15 patients were treated with
IMRT for prostate +/- pelvic nodes (14 prostate + pelvic nodes, 1 prostate+ seminal vesicles). Daily verification imaging was performed, with CBCT
on the first three fractions and weekly thereafter, and large field orthogonalkV images on other days. Marker matching was performed and corrections
applied with a tolerance of 2mm, if the bony match also agreed within 5mm.
CBCT images were reviewed by the oncologist and transferred to the planningsystem on request, for fusion and outlining of rectum, bladder and small bowel
as required. DVHs were calculated from the original planning scan based onthese volumes to assess the impact of any changes.
Results: 81% of imaging sessions were matched to fiducial marker position
under the hybrid protocol, with 13% bony matched due to differences greaterthan 5mm, and 6% bony matched due to unavailability of the kV imaging
treatment unit. Patients had 9-12 CBCT scans and an average of 5 scans
were reviewed in the planning system (range 0-9). 8 patients (53%) had
some form of intervention as a result of CBCT review: 2 were stopped early
due to rectum or small bowel DVH tolerance breaches; 2 were replanned due
to changes in external contour leading to degradation of target coverage; andin 6 cases bladder and bowel prep was re-discussed or modified to achieve
greater parity with the planning scan.
Conclusions: The use of fiducial marker localisation in large volume IMRT
should be tempered by consideration of whole target coverage and normal
tissue tolerances. CBCT is an invaluable feedback mechanism to assess thegeometric and dosimetric impact of any changes, for clinicians and physicists
alike.
1010 poster
COMPARISON OF HORMONE THERAPY ALONE WITH HORMONE
THERAPY COMBINED WITH RADIOTHERAPY FOR HIGH-RISKPROSTATE CANCER PATIENTS
P. Milecki1
1
1. G REAT P OLAND C ANCER C ENTRE , 2. U NIVERSITY OF M EDICALS CIENCES, Departments of Radiation Oncology and Cell Biology, Poznan,
PolandPurpose: To compare the efficacy of hormone therapy (HT) alone with hormone therapy combined with radiotherapy (HT +RT) in the group of high risk
prostate cancer patients.
Materials: Into analysis were included 320 high-risk prostate cancer patientstreated between 1999 and 2004. Patients were divided into 2 groups: group
1 hormone therapy alone (n=158 pts.); group 2- combined treatment of hormone therapy and 3D conformal radiotherapy (n=162 pts.). Disease staging
was based on the following steps: peripheral blood count, digital rectum examination, PSA serum level , prostate ultrasonography, bone scan, chest xray, computer tomography or magnetic resonance tomography of pelvis. Patients were eligible with pathology report of prostate adenocarcinoma gradedaccording to Gleason Score, performance status 0 or 1 according to ECOG,
lack of distant metastases, presence of at least one of the following high-risk
group factors (T3, Gleason >7 or PSA >20 ng/ml), and informed consent with
option to choose the treatment arm (HT or HT + RT). Patients were ineligible when eligibility criteria were not met or with PSA >70ng/ml.The following end-points to measure efficacy of treatment were used: overall survival,
cancer-specific survival, distant metastases progression free survival, andbiochemical progression free survival. Acute and late treatment toxicity of RT
were assessed according to EORTC/RTOG scale. The quality of life was also
evaluated for both groups. Mean total dose of radiotherapy was 70.2 Gy toprostate (range: 66 Gy 74 Gy), and 46.4 Gy (44 Gy 50 Gy) to elective pelvic

S 380P ROSTATE CANCERP ROSTATE CANCER

lymph nodes. Hormone therapy included ablation (surgical or pharmacological) or maximal androgen blockade (MAB) but for group when was combinedwith RT was started at least 2 months before RT and continued concurrently
and then administered in adjuvant fashion for minimum duration of 24 months.
Results: The 5-year overall survival (OS) was 75% in combined (HT + RT)
arm and 59% in HT, respectively (p= 0.03). Median overall survival time was62.2 months in HT alone arm and 70.8 months in combined treatment. Actuarial 5-year cancer specific survival (CSS) was 83% in (HT + RT) groupand 70% in HT group (p= 0.01). Actuarial 5-year distant metastases-free survival in (HT + RT) was 79% and 54% in HT alone group (p= 0.007). Medianbiochemical progression-free survival for HT group was 34 months and 59.4
months in HT + RT group (p= 0.000).
Conclusions: Combined treatment with hormone therapy and radiotherapy
shows benefit when compared with hormone therapy alone in terms of overall survival, cancer specific survival, distant metastases-free survival and biochemical progression-free survival. Acute and late treatment toxicity level in
combined arm was low and in addition had now adverse effect on quality oflife measures when compared to hormone therapy alone.
1011 poster
DOES MARKER-BASED PROSTATE RADIOTHERAPY CAUSEWORSE ACUTE TOXICITY?
J. Sham1 , N. Rosenfelder1 , S. Ashley2 , C. Lamb3 , N. van As4 , V. Khoo1
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of ClinicalOncology, London, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of Medical
statistics, London, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of Medical
Physics and Radiation Safety, London, United Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of ClinicalOncology, Sutton, United Kingdom
Purpose: Setup accuracy is improved using fiducial markers (FM) insteadof bony matching for image-guided radiotherapy (IGRT) for prostate cancer.
However, more reproducible setup may increase normal tissue toxicity due tothe increased reproducibility of organs-at-risk positioning, particularly in thehigh dose volume. This study compares the incidence of acute bladder (GU)and rectal (GI) toxicity with and without FMs.
Materials: Acute rectal and bladder toxicity was evaluated in 15 patientswith FM (FM+) and 15 controls without FM (FM-), selected sequentially (nonrandomised) and matched for radiotherapy technique (conformal vs intensitymodulated radiotherapy (IMRT)) and dose/fractions (#). Acute toxicity data,
recorded during treatment, was collected retrospectively and compared forthe two groups. In each group, 3/15 received 74Gy/37# with standard conformal techniques 12/15 received 74Gy/37# with IMRT
Results: Acute bladder and rectal toxicity data (RTOG grading) was available
for all 30 patients. Results are summarised in the table. GU toxicity wassignificantly better in the FM+ patients than FM- patients (p=0.03).

Cobelli4 2 , R. Orecchia3 2
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Radiation Therapy,
Milan, Italy
2
U NIVERSITY OF M ILAN, Milan, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Milan, Italy
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Urology, Milan, Italy
11013 poster

1

1012 poster
EARLY OUTCOME OF VOLUMETRIC MODULATED RAPIDARCTM
HYPOFRACTIONATED POST-PROSTATECTOMY RADIOTHERAPYOF PROSTATE CANCER
B. A. Jereczek-Fossa1 2 , D. Zerini3 , M. Bonora3 2 , C. Fodor3 , P. Fanti3 2 ,R. mauro3 2 , I. Bossi-Zanetti3 2 , M. caputo3 2 , A. Vavassori3 , S. Vigorito3 ,R. Luraschi3 , S. Comi3 , F. Cattani3 , R. Cambria3 , C. Garibaldi3 , O. De

respectively.
Conclusions: Daily CBCT with our rescan protocol may be promising to reduce the inter-fraction motions of the prostate, which were as small as 1 mm.
The rescan was needed in 5% of the IMRT fractions and could resolve thesevere misregistration mainly caused by excessive rectal gas.
1014 poster

Purpose: To report on feasibility and acute toxicity of hypofractionated volumetric arc intensity modulated radiotherapy using RapidArcTM (RA-IMRT) for
postoperative or salvage treatment of prostate cancer.
Materials: Between 2/2010 and 11/2010, 54 pts (median age 68 yrs, median
GS score 7, median iPSA 8.3 ng/ml), were treated with postoperative (34pts) or salvage RA-IMRT (20 pts) after open (31 pts), laparoscopic (2 pts) or
robotic prostatectomy (21 pts). Pelvic RA-IMRT was added in case of pN1
or high risk cN0/pNx. In case of undetectable postoperative PSA, prostatic
bed dose was 66Gy/30fr (2.2Gy/fr) equivalent to 69Gy, according to linearquadratic model with α/β of 1.5Gy. In case of detectable postoperative PSA
or salvage RT, prostate bed dose was 68.2Gy/31fr (2.2Gy/fr) (equivalent to
72 Gy) or 69Gy/30fr (2.3Gy/fr) (equivalent to 75 Gy). In case of pelvic RT,
simultaneous integrated boost (SIB) was employed and 1.7Gy or 1.8Gy x 30
fr to 51-54Gy was delivered to N0 or N+ sites, respectively. Pts were invited tohave full bladder and empty rectum, and were treated in supine position with a
Combi-fixTM device. The CTV-T included the prostatic bed with CTV-T to PTVT margins of 10 mm in all directions, except 5 mm posteriorly. Pelvic lymph
nodes volume was identified delineating pelvic vessels. Then CTV-N volume
was created adding a 8-mm margin (avoiding bone, bladder, muscle, andmesorectum). An additional 5-mm margin expansion was added to create theultimate PTV-T and PTV-N volumes. Dose volume histograms (DVHs) were
elaborated for organs at risks (urinary bladder, rectum, anal canal, peritoneal
cavity, penis, penile bulb, testicles, femoral heads) and respected for each
RA-IMRT plan according to the institutional DVHs constraints. Cone beam
CT was performed for the first 3 RA-IMRT sessions, and weekly thereafter.
Institutional action level protocol was applied to correct the set-up and organ
motion errors.
Results: All but 1 pts completed RA-IMRT (median overall treatment timewas 43 days, range 36 - 66 days). Acute toxicity was low and included genitourinary G1 events in 17 pts (31.5 %), G2 events in 4 pts (7.4 %), G3 eventin 1 pt (1.9%) and rectal G1 events in 21 pts (38.9 %), G2 event in 1 pt (1.9%), G3 event in 1 pt (1.9 %). No acute G4 events were observed. RA-IMRT
was interrupted in 2 pts (for 1 and 7 days, respectively) due to G3 events.
One patient terminated RA-IMRT at the dose of 60.75Gy due to fatigue.
Conclusions: Mildly hypofractionated RapidArc-IMRT in postoperative or
salvage setting for prostate cancer patients seems a feasible approach withexcellent acute toxicity profile and high patient compliance. Further investigation with higher patient number and longer follow-up is warranted in orderto verify if low acute toxicity observed in this series is translated to low late
toxicity and satisfactory tumour control.

EFFICACY OF DAILY CONE-BEAM COMPUTED TOMOGRAPHY
ON A RESCAN PROTOCOL FOR SEVERE MISREGISTRATION TO
REDUCE THE INTER-FRACTIONAL MOTION OF THE PROSTATE
S. Yamaguchi1

Conclusions: Neither GU nor GI toxicity is more pronounced when FMs
are used for daily setup for radiotherapy. In fact, despite the small numberof patients, a statistically significant difference in favour of FMs was seen
for GU toxicity. Further study is in progress to assess the acute and late
toxicity for patients undergoing prostate radiotherapy with and without FMs
in an International Trial. With improved setup accuracy, the calculated dose
received by organs-at-risk may represent the dose volume histogram morereliably and organ tolerances may need to be re-evaluated.

S 381

UOEH, Department of Radiotherapy, Kitakyusyu, Japan

Purpose: The purpose of this study was to analyze the inter-fraction motion of the prostate in the patients with prostate cancer treated with intensitymodulated radiation therapy (IMRT) using image-guided radiotherapy (IGRT)of daily cone-beam computed tomography (CBCT) on a rescan protocol forsevere misregistration, and to evaluate the efficacy of our protocol.
Materials: Sixty-one patients with prostate cancer underwent IMRT using thefollowing protocol; 1) a magnesium-oxide and dimethylpolysiloxane were administrated between 2 weeks before the planning CT and completion of the
IMRT, 2) patients were instructed to have an appropriate distended bladderduring the planning CT and daily irradiation and to finish a defecation before the planning CT and daily irradiation, 3) each daily kilovoltage CBCT
image was fused into the planning CT image, using prostate outline, and 4)
if severe misregistration was recognized, rescan of CBCT and re-registration
were performed after appropriate countermeasure such as discharge of gas
and defecation. In all patients, total irradiation dose was 76Gy with 38 fractions, and CBCT was performed in every IMRT fraction. Three shifts for theinter-fractional motion of the prostate were analyzed using total of 2318 CBCT
data; the data at rescan were used in the fractions which needed rescan. PTV
margin was the CTV plus 4mm posteriorly and 7mm in all other directions.
Results: The rescans of CBCT for severe misregistration were performedin 114 (5%) of 2318 fractions and in 41 (67%) of 61 patients. After the rescans, the severe misregistrations were resolved in 112 (98%) of 114 fractions.
The reasons for the severe misregistration were as follows: excessive rectalgas (n=96 fractions), artifact (n=12), excessive stool (n=1) and others (n=5).
The total mean and standard deviation (SD) of the inter-fractional motion of
the prostate in the AP, LR, and SI directions were 1.1±2.4, -0.1±2.3, and
0.7±3.0 mm, respectively. The percentage of couch shift agreements within
the PTV margin in the AP, LR, and SI directions was 97.4, 99.9, and 97.6,

EFFICACY OF KETOCONAZOLE AND DIETHYLSTILBESTROL IN
HORMONE REFRACTORY PROSTATE CANCER
M. Solak Mekic1 , M. Solaric1 , V. Mataga2 , T. Krnic1 , H. Sobat1
1
C LINICAL H OSPITAL "S ISTERS OF C HARITY "/U NIVERSITY H OSPITAL FOR
T UMORS, Department of Radiation Oncology, Zagreb, Croatia
2
U NIVERSITY H OSPITAL FOR T UMORS, Zagreb, Croatia
Purpose: Diethylstilbestrol (DES), a synthetic ethynyl estrogen, and intermediate dose ketoconazole (IDK) and hydrocortisone, a combination of antimycotic and corticosteroid, are often used as salvage therapy after several
hormone manipulations. We investigated their efficacy in patients with hormone refractory prostate cancer (HRPC).
Materials: A retrospective review of medical records of 32 HRPC pts receiving IDK and 19 pts receiving DES from Jan 2005 to Dec 2009.
Results: Prior to IDK, patients received four lines of hormonal therapy. The
median baseline serum PSA level was 75.8 ng/ml (range 1.75-563.3). A
PSA response (defined by ≥ 50% decline in baseline PSA) or any PSA decline were observed in 5 (17.9%) and 11 (39.3%) pts, respectively.For theentire study group, the median time to progression (TTP) was 2.25 months(interquartile range (IQR) 2.0-5.75 mths), and the median survival was 11months (IQR 5-21 mths). In PSA responders, TTP was significantly longer (7mths) than in PSA non-responders (2.0 mths) (p=0.014). TTP was also significantly longer (6 mths) in patients with any PSA decline than in the group
without decline (2.0 mths)(p<0.001). Intolerable side effects caused IDK discontinuation in 8 (28.6%) pts. Prior to DES, patients received one line ofhormonal therapy more than the IDK group. The median baseline serum
PSA value was 43.1 (IQR 7.1-118.8) and the median treatment duration was
8 months (IQR 3.9-10.5mths). Any PSA decline and >50% decline were observed in 11 (68.7%) and 6 (37.5%) pts, respectively. The median TTP was
7.25 months (IQR 4.0-9.25 mths) and the median overall survival was 12months (IQR 7.4-17.5 mths). Using the >50% response criteria, the median
TTP for responders was 8.25 mths compared to 4.5 mths for non-responders(p=0.093). DES toxicity was reported in only one patient.
Conclusions: Diethylstilbestrol and ketoconazole are a valuable option for
HRPC patients. DES can induce prolonged responses and is well tolerated.
Early identified PSA responders to IDK will benefit from this therapy. A substantial proportion of patients discontinue therapy due to intolerable side effects. Long responses are more likely to occur in men initiating IDK or DES
early in the course of their disease.
1015 poster
EVALUATION OF ROTATIONAL IMRT FOR THE TREATMENT OFPROSTATE CANCER PATIENTS WITH PROSTHETIC HIP
R. Venkitaraman1 , A. Esmail2 , S. Boston1 , H. James1 , C. D. Scrase1
1
S UFFOLK O NCOLOGY C ENTRE T HE I PSWICH H OSPITAL NHS T, Ipswich
Suffolk, United Kingdom
2
M OUNT V ERNON H OSPITAL, Northwood Middlesex, United Kingdom
Purpose: To evaluate the potential advantage of rotational IMRT with Varian RapidArc for treating prostate cancer patients with prosthetic hip, and adosimetric comparison with 3D CRT.
Materials: Five prostate cancer patients with prosthetic hip, due to receive
radical radiotherapy, had planning CT scans. The CTV was defined as
prostate and seminal vesicles, PTV as CTV plus margin of 1 cm. Prescribed
dose to PTV was 70Gy. Plans were generated for each sets of scans for 3D
CRT and Varian RapidArc.18 MV 3D CRT plans were created avoiding direct
beam entry through the prosthetic hip. RapidArc plans utilised a single 6MV
arc rotating from 179.90 to 180.10 , incorporating an avoidance sector during
optimisation to prevent beam entry through the prosthesis. A comparison of
the DVH by the two techniques with regards to the PTV coverage and radiation dose received by the OAR was undertaken, utilising the paired samples
T test, and p value of 0.05 was considered significant.
Results: Adequate PTV coverage was obtained with both plans with a mean
conformity index of 0.5 for Rapid Arc and of 0.6 for 3D CRT plan(p=0.28).
The average maximum dose to bladder (71.2 Vs 74.6; p=0.003) and opposite
hip (36.7 Vs 49.8; p=0.021) were lesser with RapidArc plan compared to the
3D CRT plan, while that for rectum (71.5 Vs 72; p=0.105) was similar. The
average mean dose to the rectum (46.7 Vs 52.8; p=0.209), bladder (31.3 Vs
33.5; p=0.268) and opposite hip (20.5 Vs 31.3; p=0.036) were lesser with
RapidArc plan compared to the 3D CRT, though not statistically significant.
Comparison of the individual DVHs also suggest a reduction in the bladderand rectal volume receiving each dose level for the Rapid Arc plans comparedto the 3D CRT plan (table).

Conclusions: Rotational IMRT with Varian Rapid Arc enables optimal delivery of the prescribed dose to the PTV, whilst reducing the dose to the OAR,
in comparison with 3D CRT in patients with prosthetic hip receiving radical
radiotherapy for prostate cancer, potentially reducing the acute and late sideeffects of radiotherapy.
1016 poster
FOCAL SALVAGE FOR PROSTATE CANCER RECURRENCES.
M. Peters1 , M. Moman1 , U. van der Heide1 , M. Moerland1 , S. Franken1 , J.
J. Battermann1 , M. van Deursen1 , M. van Vulpen1
1
U.M.C. U TRECHT, Utrecht, Netherlands
Purpose: Recurrent prostate cancer after previous radiotherapy can betreated with a salvage treatment of the entire prostate. Data from salvage
prostatectomy, salvage cryotherapy or salvage brachytherapy series showhigh rates of severe (grade 3 or higher) toxicity, even up to 30%. This causes
the urology community to be reluctant with regard to salvage treatments tothe entire prostate. Currently, Dynamic-Contrast Enhanced (DCE-)MRI allows localization of the recurrence within the prostate and thus enables focal
salvage. We hypothesize severe toxicity rates will be significantly reduced byusing focal salvage.
Materials: In 16 patients with biopsy proven local recurrent prostate cancer focal salvage was performed by I-125 brachytherapy. Recurrences werelocated by DCE-MRI and confirmed by a 12-core biopsy scheme. Prescription dose to the recurrence was 144Gy, GEC-ESTRO guidelines with regard
to sparing of rectum and bladder were met. Toxicity was recorded using theCommon Toxicity Criteria (CTC) and quality of life was measured using Rand36, EORTC-C30 and-PR25.
Results: With a minimum follow-up of six months, grade 3 gastro-intestinal
toxicity was observed in only 1 patient. Quality of life was not impaired.
Conclusions: Based on these preliminary data we conclude focal salvage
seemed to be technically and clinically feasible, with an acceptable toxicity
rate.
1017 poster
GENITOURINARY TOXICITY IN PROSTATE HDR BRACHYTHERAPY
E. Aleknavicius1 , A. Burneckis1 , A. Ivanauskas1
1
I NSTITUTE OF O NCOLOGY V ILNIUS U NIVERSITY, Clinic for Radiation
Therapy, Vilnius, Lithuania
Purpose: In Vilnius University Oncology Institute we started to perform HDR(high dose rate) prostate brachytherapy technique in combination with 3 D
conformal external radiotherapy for high and intermediate prostate cancer
patients in 2009-07. We treated 16 pts. until 2010-12. The follow-up ofthese patients was performed. The main purposes were to determine: acutegenitourinary (GU) and gastrointestinal side effects and toxicities, PSA value
dynamics
Materials: We performed combined modality (CM) treatment using
brachytherapy machine Varisource 200 with Iridium 195 (125Ir) source forbrachytherapy and Varian linear accelerator for external beam therapy. The
prescribed BT dose was 9,5Gy (26 izoGy) to the prostate and basis of seminal
vesicals and after 10-14 days EBRT 50 Gy to the prostate and whole seminal vesicals and regional lymph nodes (if lymph node irradiation was needed.
Treated pts. were: cT2b cT3b, Gleason score 6-7 and initial PSA value
4,13 50 ng/ml (intermediate and high risk group prostate cancer patients),
median age 56 years. The prostate volume 22 46 ml. 14 of these patients received neoadjuvant antiandrogen hormonal treatment (1 12 moths).

S 382

P ROSTATE CANCERP ROSTATE CANCER

Treatment characteristics and follow-up data were retrospectively analyzed.
3 of these patients received EBRT to regional lymph nodes, the others only
seminal vesicals.
Results: Genitourinary toxicity was graded according to the the Radiation
Therapy Oncology Group/European Organization for Research and Treatment of Cancer radiation morbidity scoring system. The incidence of slight
Grade 2 acute GU side effects was about 50%. The incidence of slight Grade2 acute GI side effects was 2% and no higher grade acute rectal side effects
was observed. It was hard to clearly summarise PSA value dynamics during
the period after this CM therapy because of short follow-up and slow, PSA
dynamics after tis type of treatment. It seems there is no point to check PSA
earlier than 3 moths after implantation and PSA could reach nadir after 12 18 moths or later
Conclusions: The longer follow-up is needed to get reliable data on PSA
dynamics and late GU and GI toxicities. The investigation showed that the
major advantage of this type of CM radiotherapy could be less acute urinaryand especially rectal toxicity with dose escalation up to 76 izoGy. The longer
follow-up is needed to get reliable data on PSA dynamics and late urinary andrectal toxicities.

androgen-senisitive group and 4/8 in androgen-resistant group), the time
to relapse range from 0,5 to 8,7 years (median 1,25). Seven patients revealed distant metastases (4/25 and 3/8, respectively) - all with diagnosed
biochemical relapses earlier. Median time to occur metastases was 2,8 years(androgen-sensitive 7,6, androgen-resistant 1,8). One patient recurred locally (androgen-sensitive subgroup), with time to recurrence 65,9 months.
The 7-year bRFS was 58%, RFS 89% , MFS 77% and OS 60%.
Conclusions: In rigorously selected patients, especially androgen-sensitive,
radical radiotherapy for high PSA can achieve satisfactory prostate cancer
control.
1020 poster
HOW BIOLOGICALLY EFFECTIVE DOSE (BED) LEVEL IMPACT
LONG-TERMOUTCOMESIN
INTERMEDIATE-RISKPROSTATE CANCER PATIENTS TREATED WITH HIGH-DOSERATE BRACHYTHERAPY
H. Ye1 , A. Martinez1 , D. Krauss1 , L. Kestin1 , M. Ghilezan1 , G. Gustafson1
1
W ILLIAM B EAUMONT H OSPITAL, Radiation Oncology, Royal Oak, USAand dysuria. Presently, post RT PSA values are being requested and will bereported as well as serial post-RT PSA determinations.
Conclusions: The use of Hypofractionated IG-IMRT in the Philippine setting
is viable and have shown minimal side effects. This method of treatment
allows dose escalation with greater chances of tumor control with minimalside effects. The availability of IG- IMRT in the Philippine setting has allowed
the investigators to use higher doses per fraction with confidence because of
its accuracy and precision. At the same time it is cost beneficial to the patient
because of the over-all decrease in treatment time.
1022 poster
IMPACT OF ANDROGEN DEPRIVATION ON THE PROGNOSTICVALUE OF NEUROENDOCRINE DIFFERENTIATION FOR HIGHGRADE PROSTATE CANCERS TREATED WITH RADIOTHERAPY
D. Krauss1 , M. Amin2 , S. Hayek2 , H. Ye1 , L. Kestin1 , F. Vicini1 , M.
Ghilezan1 , D. Brabbins1 , G. Gustafson1 , A. Martinez1
1
W ILLIAM B EAUMONT H OSPITAL, Radiation Oncology, Royal Oak, USA
2
W ILLIAM B EAUMONT H OSPITAL, Pathology, Royal Oak, USA

1018 poster
HIGH-DOSE-RATE (HDR) BRACHYTHERAPY WITH EXTERNAL
BEAM RADIOTHERAPY FOR LOCALIZED HIGH RISK PROSTATECANCER: 5-YEAR RESULTS IN 141 PATIENTS
K. Masahito1 , K. Miki1 , M. Aoki2
1
J IKEI U NIVERSITY S CHOOL OF M EDICINE, Department of Urology,
Minato-ku, Japan
2
J IKEI U NIVERSITY S CHOOL OF M EDICINE, Department of Radiation
Oncology, Minato-ku, Japan
Purpose: To present outcome and morbidity of high-dose-rate (HDR)
brachytherapy with external beam radiotherapy (EBRT) for localized high risk
prostate cancer.
Materials: Between May 2005 and April 2009, 131 patients underwent Ir-192
HDR brachytherapy with EBRT and passed after HDR bachytherapy morethan one year. The median follow-up was 26 months (range 2-52 months).
All patients were high risk and localized prostate cancer. Median PSA was
25.3ng/ml (range 4.1-201ng/ml). Median Gleason Score was 8 (range 6-10).
Initial 77 patients, the total prescribed dose was 11Gy in 2 fractions of HDR
and 45Gy in 15 fractions of EBRT. Recent 64 patients, 18Gy in 2 fractionsof HDR and 40Gy in 16 fractions of EBRT. All patients were treated over six
months neo-adjuvant hormonal therapy and over twenty-four months adjuvant
hormonal therapy.
Results: Only one patient had died of lung small cell carcinoma. Five patients
had revealed biochemical (BC) failure by Phoenix definition. BC free rate was
80.5%. Of the 131 patients, only one patient displayed Grade 3 late GI toxicity.
There were no other acute nor late severe toxicity.
Conclusions: HDR brachytherapy for localized high risk prostate cancer resulted in good outcomes and had comparatively minor toxicity. Based on thisresult, we are planning the clinical prospective randomized study for HDR in
Japanese high risk prostate cancer.
1019 poster
HIGH-RISK PROSTATE CANCER PATIENTS WITH INITIAL PSA100
NG/ML TREATED WITH EXTERNAL-BEAM RADIOTHERAPY.
B. Smolska-Ciszewska1 , G. Plewicki1 , M. Giglok1 , K. Behrendt1 , M.
Gawkowska-Suwinska1 , E. Nowicka1 , T. Dworzecki1 , U. Dworzecka1 , A.
Zajusz1
1
M ARIA S KŁODOWSKA -C URIE M EMORIAL C ANCER C ENTER AND I NSTITUTEOF O NCOLOGY, G LIWICE B RANCH , II Radiotherapy Clinic, Gliwice, Poland
Purpose: To assess the outcome of patients with initial PSA of 100 ng/ml or
higher undergoing radical radiotherapy for prostate cancer.
Materials: Thirty three patients with a median age of 65 years (range: 5374) underwent external beam radiotherapy (EBRT) in our department. The
initial PSA range from 100 to 930 ng/ml (median 136). The stage distribution was: T1c - 5 patients (15,2%), T2a 1 (3%), T2b - 11 (33,3%), T2c 8 (24,3%), T3a 7 (21,2%), T3b 1 (3%). Five patients had node metastases (N1). The Gleason score range from 3 to 8 (median 7). The resultsof imaging tests (bone scan, abdominopelvic ultrasound, CT or MRI, chest
X-ray) were all interpreted as being normal. Hormonal therapy prior to radiotherapy was applied in all patients with median duration time of 6,5 months(range: 3-38,8). Twenty five patients were androgen-sensitive at the beginning of radiotherapy, 8 - androgen-resistant. All patients underwent EBRT.
Adjuvant androgen deprivation was used in 26 cases (78,8%), the duration
time of adjuvant therapy range from 4,5 to 53 months (median 22,4). The
efficacy of the treatment was evaluated by biochemical relapse free survival(bRFS), metastases-free survival (MFS) recurrence-free survival (RFS) andoverall survival (OS). Kaplan-Meier method was used to plot survival curves.
Results: All patients were followed continuously during a median of 4 years(range 1-12 years). Biochemical relapses occurred in 11 cases (7/25 in

Purpose: We are reporting the 10-years prostate cancer related events andsurvival outcomes for intermediate-risk prostate cancer patients treated with
HDR brachytherapy.
Materials: From 1991 to 2010, 1047 men were treated with dose escalated
HDR brachytherapy boost and HDR monotherapy for prostate cancer. Seven
hundred seventy one men had either one or more intermediate-risk features(prostate-specific antigen [PSA] level 1020 ng/mL, Gleason score 7, or StageT2b). Biologically effective dose (BED) values were calculated by using α/f1.5. Patients were stratified according to BED. BED ranged from 184 to 278.
Low dose level was considered as BED ≤ 227 Gy1.5 and high dose level was
BED >227 Gy1.5. Biochemical failure was analyzed by the Phoenix (nadir+2
ng/ml) definition, clinical failure (CF) was defined as any locoregional recurrence (LRR) or distant metastasis (DM). Univariate analyses were used todetermine whether any patient characteristics and treatment related factors
was predictive for prostate cancer related events and survival. A two-sided pvalue of <0.05 was considered significant.
Results: The median follow-up time was 7.2 years (0.4-18.96 years). At 10years, CF was 19.2% and 3.3% for low-dose and high-dose level (p<0.001),
DM was 11% vs. 2.1% (p=0.002), OS was 70.5% and 81.0% (p=0.025),
respectively. On univariate analysis, increasing CF was associated with increasing PSA (p=0.025), higher stage (p=0.004), lower BED level (p=0.001),
and number of risk factors (p<0.001); BC was associated with Gleason score(p=0.042) and number of risk factors (p=0.012); DM was associated withstage, BED level and number of risk factors with p-value 0.049, 0.005, and
0.001 respectively. BED was the only factor significantly impact on OS withthe p-value 0.026. On multivariate analysis, BED and number of risk factors
were found to be associated with CF, DM and OS.
Conclusions: Radiation dose is an important predictor for CF, DM and OS inintermediate-risk prostate cancer patients. However, high BED has not foundto significantly impact on BC.
1021 poster
HYPOFRACTIONATED IMAGE GUIDED IMRT FOR PROSTATECANCER:PHILIPPINE’S FIRST CLINICAL EXPERIENCE
G. Banuelos1 , C. Aguilar1 , M. Cruz1 , M. Olvina1 , T. Sarmiento1 , E.
Tangco1 , N. Arriola1 , C. De Villeres1
1
S T F RANCES C ABRINI M EDICAL C ENTER AND C ANCER I NSTITUTE,
Department of Radiation Oncology, Sto Tomas, Philippines
Purpose: Dose escalation with Intensity Modulated Radiation Therapy(IMRT) and Hypofractionation in the treatment of Prostate Cancer has shown
improvement in local control and has minimized the acute and late toxicities
of normal tissues. The advent of Image Guided Radiation Therapy (IGRT) allowed greater accuracy and precision in daily treatment and higher doses per
fraction to be delivered safely. The first IGRT machine for the Philippines wasstarted in 2008. In 2009, we started the Hypofractionated IG-IMRT treatment
for Prostate Cancer. This is a report on our clinical experience regarding thismodality.
Materials: Elekta synergy E1594 system which integrates an X-ray volumetric imager (XVI) and Cone Beam Ct-scan, was used to treat the first 4 casesof Prostate cancer with Hypofractionated IMRT using 6 MV photons. All patients have Gleasons Score between 6-8. Between 5-9 non-coplanar beams
were generated via forward planning using Precise treatment planning system. Image guided on-line registration using Cone Beam Computed Tomography (CBCT) was done daily before treatment. A total dose of 64Gy in 20
fractions was given in 4 weeks. Acute toxicity for the GIT and GUT regions
were monitored at the end of each week.
Results: The mean dose received by the CTV was 65.24 Gy. The criticalstructures received the following mean doses: rectum 37.49 Gy; bladder
31.93 Gy; small bowels 12.40 Gy. Acute upper GIT reactions was Grade
1 with nausea. Acute lower GIT reactions was Grade 1, 2 with diarrhea andmild abdominal pain. Acute GUT reactions was Grade 1, 2 with frequency

Purpose: Prior analysis has demostrated that neuroendocrine differentiation(NED) in Gleason score 8-10 prostate cancers treated with radiotherapy (RT)is associated with increased rates of distant metastases and inferior causespecific survival. Much of the theoretical explanation for this observation has
related to an increased resistance to androgen deprivation therapy (ADT).
We conducted a subset analysis correlating clinical outcomes with degree of
NED stratified the the administration of ADT.
Materials: Chromogranin A (CgA) staining was performed and overseen by asingle pathologist on core biopsies from 176 patients from the William Beaumont Hospital prostate cancer database. 142 had evaluable biopsy material
and available data pertaining to the administration of ADT. CgA staining wasquantified as 0%, <1%, 1-10%, or >10% of observed tumor cells. Clinical outcomes were blinded at the time of staining. Patients received external beam
RT alone or together with high dose rate brachytherapy boost between years
1987 and 2007. Subgroups of patients were generated based categoricallyon whether or not any ADT was administered. Cox regression and Kaplan
Meier estimates determined if the presence of NED correlated with clinicalendpoints.
Results: Median follow-up for the entire patient cohort was 5.5 years. 59
patients (42%) received and 83 (58%) did not receive ADT. For those receiving ADT, the presence of CgA staining was noted in 18 patients (31%) andwas not associated on Cox regression with increased rates of biochemical,
clinical, or distant disease failure. Likewise, no differences in cause-specificor overall survival were appreciated. For the 83 patients not receiving ADT,CgA staining was significantly associated (p<0.05) with inferior 10-year rates
of freedom from distant metastases (79.1% vs. 57.9%) and cause-specificsurvival (89.4% vs. 65.8%). While there was suggestion of inferior rates ofbiochemical control and any clinical failure for these patients, it did not reachstatistical significance.
Conclusions: The poor prognosis conferred by the presence of NED inpatients with high-grade prostate cancers does not relate exclusively to increased resistance to ADT.
1023 poster
IMPACT OF POSTURAL CHANGES IN POSTIMPLANT DOSIMETRICANALYSIS FOR I-125 PROSTATE BRACHYTHERAPY
T. Ohashi12 , T. Momma3 , S. Yamashita2 , T. Hanada1 , J. Fukada1 , N.
Shigematsu1
1
K EIO U NIVERSITY S CHOOL OF M EDICINE, Department of Radiotherapy,
Tokyo, Japan
2
S AITAMA H OSPITAL , N ATIONAL H OSPITAL O RGANIZATION, Department ofRadiology, Saitama, Japan
3
S AITAMA H OSPITAL , N ATIONAL H OSPITAL O RGANIZATION, Department ofUrology, Saitama, Japan
Purpose: Postimplant dosimetric assessement is essential for optimal patientcare. In most institutions, postimplant CT scans are performed in supine position. The aim of this study is to assess the variability of dosimetric parametersby postural changes in acquisition of postimlant CT imaging.
Materials: A total of 85 consecutive patients agreed to participate in thisstudy. Fifty-three patients received seed implantation alone and the remaining 32 patients received combined therapy of seed implantation and externalbeam radiotherapy. For postimplant analyses, CT scans were obtained inthree patterns of patient’s position, such as supine, prone, and left lateral decubitus. To evaluate the variabilities of the dosimetric parameters followedby postural change, the results are given in terms of relative differences withreference to the value of supine position. All of the postimplant dosimetries
were performed by one investigator experienced in postimplant analyses.
Results: The median volume of prostate was 22.4mL in supine, 22.5mL in
prone (p=0.51), and 22.7mL in left decubitus (p=0.46). The median value of
prostate D90 was 120.1%, 120.3% and 119.1% in supine, prone and decubitus, respectively, without statistical differences. The mean value of prostate

S 383

V100 was 97.1%, 97.0% and 96.9% in supine, prone and decubitus, respectively, also without statistical differences. The mean rectal V100 was 0.42mL,
0.33mL (p<0.01) and 0.34mL (p<0.01) in supine, prone and decubitus, respectively, with significant differences compared with supine position. The
rectal D2cc decreased significantly in prone position compared to supine position (mean, 59.1% vs. 63.6%; p<0.01), but there was no significant difference between supine and decubitous position. The larger postimplant
prostate volume was the predictive factor affecting decreased rectal dosesby the postural change.
Conclusions: There were no significant differences among the prostate D90
assessments by the postural changes. This study suggests that the postimplant rectal doses can decrease in prone position.
1024 poster
INDEPENDENT ASSESSMENT OF INTRAFRACTION PROSTATEAND PATIENT MOVEMENT FOR IMRT PATIENTS WITH RECTALBALLOON
E. Steiner1 , M. Stock1 , G. Goldner1 , D. Georg1
1
M EDICAL U NIVERSITY V IENNA , AKH, Department of Radiotherapy,
Vienna, Austria
Purpose: The purpose of this work was to investigate the movement of theprostate for IMRT patients during a treatment fraction. To reduce prostatemotion an endorectal balloon was utilized. The shift of bony structures wasmeasured additionally in order to determine patient movements during thedelivery of an IMRT fraction. Thus, a differentiation between the prostate andthe whole patient movement was included in the analysis.
Materials: Ten prostate cancer patients, each with 3 implanted fiducial gold
markers (1.2 mm diameter, 3 mm length) within the prostate, were immobilized in supine position utilizing a knee support. To spare the rectal wall and toimmobilize the prostate a 40 ccm endorectal balloon was used. After the first
setup based on skin marks patients were imaged using the BrainLAB ExacTrac stereoscopic imaging system. If the marker displacement exceeded thetolerance of 3 mm in relation to the marker positions on the planning CT, thepatients were shifted accordingly and verification images were taken. Additionally, patients were imaged during (approximately at halftime) and after thetreatment to obtain a time trend of the current position of the prostate and thebony anatomy. Marker/prostate and bone drifts were evaluated as a functionof treatment time for more than 350 treatment fractions.
Results: The patient movement evaluated by bone match seems to bestrongly patient dependent. Nevertheless, when applying a paired t-test generally a significant motion in lateral and longitudinal direction with increasing
treatment time was determined. At the end of a treatment fraction the bone
movement was 0.9 mm and 0.5 mm on average. The mean total treatment
time was 13 minutes. The largest movements of bony anatomy with a magnitude of 12 mm, however, were measured for one patient in vertical direction.
In contrast, marker (=prostate) drifts are less dependent on patients and show
a significant increase with treatment time in longitudinal and vertical direction.
On average the net prostate displacement corrected for patient movement at
the end of one fraction is 1.6 mm and 1.9 mm for longitudinal and verticaldirection, respectively. In lateral direction the prostate stays stable at its position.
Conclusions: As intrafraction prostate and patient motion causes significant
positioning errors, for reducing the treatment margin repositioning of the patients during the treatment will be necessary. As bone drift increases as afunction of treatment time patients seem to become the more uneasy thelonger the treatment takes shorter IMRT fractions should be considered.
New treatment techniques like rotational IMRT will help to tackle the issue
of intrafraction motion effects.
1025 poster
INTENSITY MODULATED RADIATION THERAPY FOR PROSTATECANCER
S. Obata1 , H. Takatsuki1 , Y. Ohta1 , T. Kan1 , S. Kanegae1 , Y. Inoue1 , M.
Matsuo2
1
N AGASAKI P REFECTURE S HIMABARA H OSPITAL, Department of Radiology
and Radiotherapy, Shimabara, Japan
2
N AGASAKI P REFECTURE S HIMABARA H OSPITAL, Department of Urology,
Shimabara, Japan
Purpose: A total of 222 patients of localized and locally advanced prostatecancers have been treated the intensity modulated radiation therapy (IMRT)
between January 2005 and December 2009. We have initially treated prostatic cancers with a total dose of 72Gy, and finally 76Gy from January 2004.
We herein present and discuss their therapeutic effects and adverse events.
Materials: The clinical records of 183 patients were selected and evaluated.
The mean age was 72 years old, ranging from 53 to 85 years old. The valueof PSA was 4 to 250ng/ml, Gleason score (GS) was divided into score 6
in 49, score 7 in 54, over8 in 70 and unclassified score in 10. The clinicalstages were classified into T1c/T2 in 126, T3 in 45, T4 in 3, T4N1 in 2, and
TX in 7.The clinical target volume(CTV) was follows; prostate and proximal

S 384

P ROSTATE CANCERP ROSTATE CANCER

two third of the seminal vesicle (when T3b and more, all parts of the seminal
vesicle and the invasive lesions), The planning target volume (PTV) by LG
was limited CTV plus 10 mm out of the margin, and CTV plus 6 mm out of
the margin directed to the rectum in fitting the contour of pelvic bone until
March 2007. By using Sonarray, directed target contour could be done fromMay 2007. PTV was finally fixed CTV plus 5mm (CTV plus 3.5 mm directedto the rectum). The total irradiation dose was 72Gy in 24, 74Gy in 30, 76Gy
in 119, and <70Gy in 10. A total of 149 patients (82. 3%) were treated with
neo-adjuvant endocrine therapy between 3 months and 9.5 years.
Results: All of acute adverse events were grade 1 as follows; frequent urination in 31.1%, urinary disturbance in 20.8%, anal and rectal bleeding / rectal
flame in 8.1%, anal pain in 4.9%, dermatitis in 0.5%, microscopic hematuria in
0.5%. Late adverse events were almost grade 1 (we could follow 96 patients)
as follows; anal and rectal bleeding/rectal flame in 17.7% (only 1 patient wasgrade 3), frequent urination in 0.1%, anal pain in 0.1%. PSA failure was only
2% (both patients were high risk group).
Conclusions: IMRT for prostate cancer is good therapeutic option and adverse events were in within an acceptable range.
1026 poster
INTRA-PROSTATIC FIDUCIAL MARKER STABILITY; SUB-MMAVERAGE MARKER DISPLACEMENT THROUGHOUT TREATMENT
K. Aitken1 , C. Lamb2 , N. Rosenfelder3 , K. Burke2 , M. Bidmead2 , N. vanAs4 , V. Khoo3
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of ClinicalOncology, London, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Medical Physics,
London, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Clinical Oncology,
London, United Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Clinical Oncology,
Sutton, United Kingdom
Purpose: The accuracy of prostate radiotherapy can be improved by using
fiducial markers for setup instead of bony anatomy. However marker displacement over the course of treatment may limit the accuracy achieved. Previous
studies have reported mean ± SD changes in inter-marker position of 1.2±0.2 mm during treatment but movement up to 4-10mm was seen in eachstudy. The aim of this study was to compare the stability of fiducial markers
used in our institution to the published data.
Materials: 26 patients each underwent insertion of 3 markers prior to RT
planning. Reference inter-marker distances were calculated from the planning CT. 794 daily image sets were acquired for setup (14-37 per patient),
consisting of BrainLab ExacTrac orthogonal kV image pairs (394), Varian OBI
orthogonal kV image pairs (332), Varian OBI kV CBCT (64) or orthogonal
MV EPID image pairs (4). Each marker was identified in each image, 3D
coordinates determined, and inter-marker separations calculated. For eachresult the difference from reference situation was calculated. Changes ininter-marker separation from baseline were defined as marker displacement.
Results: A total of 786 image sets (99%) were suitable for analysis (8-37 per
patient). Average (±SD) marker displacement for all patients and all fractions
was 0.2±0.8mm. All marker displacements for all fractions were ≤1mm in
2 patients (7.7%), ≤2mm in 18 (69.2%) patients, ≤3mm in 24 (92.3%) patients and ≤4mm in 25 (96.2%) patients. In 25 patients the average marker
displacement was ≤1mm for all markers throughout the course of treatment.
Migration of 1 marker was seen in 1 patient. In this patient, marker displacements >4mm were identified in 6 of the first 8 fractions, but from fraction 9
this increased considerably (separation changes 25-58mm), at which time
this marker was excluded for setup.
Conclusions: These results compare favourably to the published data anddemonstrate that fiducial marker position is relatively stable during a course oftreatment. All patients had marker displacement ≤4mm except in one patientwhere marker migration occurred. Changes in marker position may reflect underlying prostate deformation in response to treatment. These results should
be taken into account when assessing potential margin reduction.
1027 poster
IS DAILY ONLINE CORRECTION BENEFICIAL FOR PROSTATERADIOTHERAPY?
N. van As1 , N. Rosenfelder1 , C. Lamb1 , U. Schick1 , K. Burke1 , M.
Bidmead1 , A. Aitken1 , V. Khoo1
1
R OYAL M ARSDEN H OSPITAL, London, United Kingdom
Purpose: Setup errors (SE) for prostate radiotherapy (RT) with fiducial markers (FM) can be reduced using an on-line correction protocol. This enables
setup margin (SM) reduction. Additional time required for post-correction
imaging may be problematic for busy departments and correcting errors below a certain tolerance may provide little benefit. This study assesses the
improvement in SE and resulting SM using daily on-line correction and theeffect of applying different tolerances, whereby errors within tolerance are notcorrected.

1030 poster

Materials: 13 patients undergoing prostate RT received ≥10 fractions using
daily ExacTrac imaging. 3 FM/patient were inserted prior to RT. 258 image
pairs were acquired after initial setup and shifts applied for all fractions using
FM registration.
 Imaging was repeated post-correction. Population system) (standard deviation of per-patient mean) and random errors
atic errors ((σ ) (mean of per-patient standard deviation) pre- and post-correction were
calculated. The effect of setting theoretical tolerances of 4mm/o and 5mm/o
was assessed. For each tolerance, if all translational/rotational errors on initial setup were within tolerance, initial errors were copied to post-correction
errors, as if shifts had not been applied.
SM was calculated using the van+0.7σ ).
Herk recipe for each tolerance (SM=2.5
Results: Wrong block type.
Conclusions: Daily online correction allows large reduction in SE and the SM
required. 5mm/o tolerance reduced post-correction imaging by 34% whilst
enabling clinically significant SM reduction. 4mm/o tolerance provided furtheroimprovement but with 17% more imaging required.
 Tolerances <4mm/ proerrors such as intrafraction
vided little additional benefit. Other sources of
motion, and delineation and imager/linac coincidence errors must be considered before margin reduction.

LDR IODINE-125 BRACHYTHERAPY AS BOOST IN CURATIVEINTENT RADIOTHERAPY OF PROSTATE CANCER
Z. Fekete12 , D. Dordai3 , G. Kacso12 , C. Mocan1 , E. Dordai3
1
I NSTITUTE OF O NCOLOGY P ROF. D R . I. C HIRICUTA, Department ofRadiation Oncology, Cluj Napoca, Romania
2
UMF C LUJ, Cluj, Romania
3
I NSTITUTE OF O NCOLOGY P ROF. D R . I. C HIRICUTA, Department ofMedical Physics and Radiation Safety, Cluj Napoca, Romania

1028 poster
IS THERE A BENEFIT OF HORMONAL THERAPY FOR PATIENTSWITH HIGH RISK PROSTATE CANCER IN THE ERA OF DOSEESCALATED IMAGE-GUIDED RADIATION THERAPY
J. Huang1 , A. Martinez1 , D. Brabbins1 , S. Li1 , H. Ye1 , M. Ghilezan1 , L.
Kestin1 , F. Vicini1
1
W ILLIAM B EAUMONT H OSPITAL, Radiation Oncology, Royal Oak, USA
Purpose: To retrospectively review the impact of long-term hormonal therapy(HT) for high-risk prostate cancer (HR-PCa) patients treated with externalbeam radiotherapy (EBRT) using image-guidance and dose-escalation.
Materials: One hundred and sixty-eight HR-PCa patients (as per the NCCN
criteria) were treated with dose-escalated adaptive image-guided EBRT(IGRT, median dose 75.6 Gy, range 70.2-79.2Gy) from 1998-2009. Neoadjuvant and/or adjuvant HT were given to 127 patients (76%). Multivariate cox regression analysis (MVA) included Gleason score, PSA, T stage, RT dose, HT,and age. Biochemical failure (BF) was scored according to the Phoenix definition. Clinical failure (CF) was defined as any locoregional recurrence (LRR)or distant metastasis (DM). All endpoints were calculated from the completionof IGRT.
Results: Median follow-up was 4.4 years (range 0.59-10.3), and median PSA
follow up was 3.5 years (range 0.44-10.2). Distribution of NCCN high-risk features were: 10% T3, 39% PSA >20 ng/mL, 71% Gleason 8-10. HT group had
younger age and higher percentage of Gleason 8-10 (p < 0.05) as comparedto the no HT group. However, race, RT dose, pretreatment PSA and clinicalT-stage were not significantly different between the two groups. BF, LRR, DM,
CF, cause-specific survival (CSS) and overall survival (OS) were not different
between the HT and no HT groups (all p > 0.05, and see Figure 1). Subset
analysis restricted to those with Gleason 8-10 yielded the same results. On
MVA, HT was not a significant predictor for BF, LRR, DM, CF, CSS and OS(all p > 0.05).
Conclusions: The routine use of long-term HT with dose-escalated IGRT
for HR-PCa may warrant further investigation. Certain Subset of HR-PCa
patients may not derive significant benefit from HT when treated with doseescalated IGRT.

S 385

1029 poster
LATE TOXICITY OF RADICAL RADIOTHERAPY TO THE PROSTATEIN YOUNG VERSUS OLDER MEN WITH NON METASTATICPROSTATE CANCER
C. Driscoll1 , A. Montazeri1 , W. Myint1 , H. Wong1 , I. Syndikus1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Bebington, Merseyside, United
Kingdom
Purpose: Radical radiotherapy (RT) to the prostate in combination with hormonal treatment is an alternative to radical prostatectomy in patients withnon metastatic prostate cancer. In younger men (men <60 years old) there
is a preference towards surgery because of a possible increased late toxicity
including second cancers. However there is some evidence showing no difference in terms of toxicity amongst different age groups1 . Complications ofradical prostatectomy may affect the patients’ quality of life2 .In this retrospective study we have investigated the hypothesis that there is no difference inlate effect toxicity between younger (age <60) and older patients (age ≥60)
therefore radiotherapy can be recommended for younger patients with an acceptable toxicity.
Materials: The records of 120 patients with non metastatic prostate cancer(T1-3) who received radical radiotherapy +/- hormone at the Clatterbridge
Centre for Oncology between January 2004 and October 2009 were reviewed. Patients were divided into two age groups: 60 younger cases (age <60) and 60 matched older controls. In the matched older group patients werematched to their age +10 years +/- 2 years and T staging. Patient and tumourcharacteristics including, age, performance status, TNM staging, initial PSA,
Gleason score, duration of hormonal treatment, and RT dose/ fractionation
were recorded. The bladder and rectal toxicity at last clinic follow up werescored according to the RTOG scoring system. All data were analysed byusing SPSS V18.
Results: The mean age was 56.4 years (range=55-58) for the younger group
and 66.1 years (range=63-70) for the older group. T stage for the younger
and older group were T1=23%, T2=45%, T3=32% vs. T1=23%, T2=42%,
T3=35% respectively. There was no grade 3 bladder or rectal toxicity seenin either group. The grade 1 and 2 bladder toxicity was seen in 17% and
2% respectively among younger patients compared to 33% and 7% in older
groups. (p=0.11) There was 2% grade 2 rectal toxicity in younger group while
5% was noted among the older group. The grade 1 rectal toxicity was seen
in 18% younger patients compared to 32% of older group (p=0.41).
Conclusions: Our study shows that there is no statistically significant difference between the two age groups in terms of maximal bladder or rectal
toxicities.

Purpose: To evaluate the efficacy and toxicity of combined brachytherapy
and external beam conformal radiotherapy in the treatment of locally advanced or high risk prostate cancer.
Materials: Between Jan. 2007 and May 2010 we have prospectively included
53 advanced/high risk prostate cancer patients to receive I125 LDR BT followed by 3DCRT. Additionally, neoadjuvant and adjuvant hormonal treatment
was performed in the majority of the patients. Two patients were excluded
from the present analysis because they didn’t receive EBRT. One developed
ALL and died and for the second, a PET-CT performed after the BT showed
a positive iliac lymph node.The age ranged from 51 to 81 years. From 51
patients, 39 (76.5%) were stage cT3a, 4 cT3b, 4 cT2a, 2 cT2c and 2 patients
T1c. All patients were cN0M0 on abdominal CT and bone scintigraphy. All
were high risk after D’Amico’s classification. The PSA varied between 3.7-42
ng/ml, with a median of 17.The prescription dose was 110 Gy for the BT and
45 Gy/25 fr for EBRT. The exceptions were 3 patients, who received 49-50 Gy,
to compensate a suboptimal post-implant dosimetry. The CTV on the EBRT
included the prostate and the extracapsular extension plus the base of theseminal vesicles. In cT3b patients the entire volume of the seminal vesicles
was irradiated and for a risk of over 15% of subclinical lymph node metastases, the regional lymph nodes were included too. The prostate volume on
BT was between 12 and 58 ml, between 8 and 21 needles were used andbetween 23 and 60 seeds.
Results: In all cases D90% for the BT CTV was over 120% from the prescribed dose and V100% over 99%. D10 for the urethra was over 150% fromthe prescribed dose in just 7 cases (max. 158%). Rmax at the rectal mucosa was over 100% only in 4 cases (max. 115%). After a median follow
up of 20 months (4-43) after BT, only one patient presented relapse (bonemetastases after 2 years of the treatment). Four patients presented bounce
PSA (nadir+0.2) and one patient biochemical failure (nadir+2), but without evidence of the disease on prostate biopsy, abdomino-pelvine CT and scintigraphy. Regarding late grade 3-4 toxicities, 4 patients (8%) developed urethralstricture requiring dilatation (at 6-19 months), one developed acute urinary
retention requiring urethral catheter and one patient developed severe, G3pollakiuria. One patient developed rectal necrosis after he was biopsied inanother hospital for hematochezia. Because of the combined hormonal treatment the sexual toxicity of the radiotherapy is not evaluable.The toxicity of thetreatment did not correlate with the BT dose on organs at risk.
Conclusions: On short term, combined BT and EBRT plus 2-3 years of hormonal treatment seems to be an efficient and safe choice for locally advanced
or high risk prostate cancer.
1031 poster
METHOD FOR ONLINE X-RAY GUIDANCE DURING DELIVERY OF
MRI BASED HDR BRACHTHERAPY FOR PROSTATE CANCER
J. Abed1 , A. Rink1 , A. Beiki-Ardakani1 , J. Publicover1 , G. O’Leary2 , D.
Iupati1 , C. Elliott3 , D. Jaffray1 , C. Menard1
1
P RINCESS M ARGARET H OSPITAL, Radiation Medicine Program, Toronto,
Canada2
TORONTO G ENERAL H OSPITAL, Anesthesia, Toronto, Canada
3
H OLOGIC
Purpose: HDR prostate brachytherapy is a precise treatment mandating highperformance in accuracy of delivery. Where time elapses between planningand delivery, catheter displacement remains a concern. Furthermore, theaccuracy of the first dwell position depth is limited by slice thickness resolutionin MRI. We hypothesized that x-ray imaging during a dummy cable check of
the first dwell position would improve accuracy.
Materials: Patients were enrolled on a prospective clinical trial of MRI-guided
and tumor-targeted salvage HDR prostate brachytherapy performed under
Propofol sedation to minimize patient movement. Foley balloon (FB) was
inflated with 10cc of diluted Visipaque. Once catheters are inserted into
the prostate, the template (Sentinelle Medical Inc.) is locked and a highresolution MRI image acquired for planning (Axial T2-weighted FSE, 2mm
slice thickness). We identified 5 factors for catheter displacement prior to delivery: insertion/removal of obturators, attachment of transfer tubes, patienttransport, and elapsed time. Care was taken to verify stable catheter depths
at the template surface. C-arm fluoroscopy was used to acquire lateral X-ray
projections (9MAs, 110KV) of the dummy cable while paused for 5 seconds
at the first dwell position of each catheter. The SI co-ordinate of the firstdwell position was measured relative to implanted fiducial markers (FM) andFB (using MIPAV), and quantitatively compared to the geometry derived from
the MRI-based treatment plan. X-ray images and 3D projections of MRI dataS 386

P ROSTATE CANCERP ROSTATE CANCER

were also qualitatively reviewed for concordance.
Results: Patients remained immobilized throughout the procedure. X-ray
data was analyzed for 3 procedures to date. The average elapsed time between MRI imaging and the dummy cable check immediately prior to treatment delivery was 81 minutes. Images of the first procedure were analyzed
offline, whereby no offset corrections were applied to the treatment plan prior
to delivery. Mean SI error between actual and planned conditions was 1.8 mm(SD 1.4mm). First dwell position depth error exceeded MRI voxel resolution in
3/18 catheters, up to 5mm. For the subsequent procedures, offset corrections
were applied to the treatment plan prior to delivery. Qualitative image review
was concordant with the measured depth errors for all catheters. Depth errors
were not predicted by inspecting shifts at the template surface. The first dwell
position was revised in 6/29 catheters, with a mean SI correction of -2mm(range -4 to 4mm).

Conclusions: Catheter depth errors were identified despite controlled conditions and relatively short elapsed times between MRI imaging and treatment
delivery. Online X-ray imaging can improve SI accuracy by increasing the image resolution of the first dwell position to sub-millimeter scale, and correctionof the treatment plan based on the actual depth of the first dwell position

1033 poster
OUTCOME AUDIT ON POST-OPERATIVE PROSTATE RADIOTHERAPY
S. Vengalil1 , L. Shum1
1

B ELFAST C ITY H OSPITAL, Clinical Oncology, Belfast, United Kingdom

Purpose: BackgroundThe role of post-prostatectomy radiotherapy remains
controversial.There is uncertainty whether post-prostatectomy radiotherapy
should be administered adjuvantly or for salvage when PSA level rises. But
there is mounting evidence that immediate radiotherapy in high risk clinicopathological cases is superior to observation alone. Studies have demonstrated improved biochemical control and/or disease free survival with adjuvant radiotherapy, but it’s benefit in terms of overall survival is not clear.
Approximately 15-40% of patients will experience a biochemical recurrence
within 10 years after surgery. The factors which identify risk of biochemical failure include positive surgical margins, Gleason score, extra-capsularextension, seminal vesicle invasion, positive lymph nodes and pre-operative
PSA levels.ObjectivesTo evaluate outcome and toxicities of adjuvant and salvage radiotherapy treatment following radical prostatectomy and comparewith standards published from clinical trials.
Materials: Retrospective review of case notes of patients who received postprostatectomy radiotherapy between January 2000 and December 2008 at
our institution. We collected information on baseline patient characteristics,
pathology details, radiotherapy dose, acute/late radiotherapy toxicity and outcome data (biochemical and clinical control). The RTOG/EORTC criteria wereused to evaluate radiotherapy toxicities. We used ASTRO definition to definebiochemical failure following EBRT. Survival rate was determined using the
Kaplan-Meier life table analysis.
Results: Median follow-up was 31.2 months (3.2 - 104.5).Biochemical failure
free survival at 36 months was 79.6% for adjuvant radiotherapy comparedto 62.8% for salvage radiotherapy (p= 0.2919), which are similar to results
published from clinical trials.

PRIMARY RADIOTHERAPY AND HORMONE THERAPY IN PATIENTSWITH HIGH-RISK PROSTATE CANCER: PRELIMINARY RESULTS
OF A RANDOMIZED TRIAL
M. Ibraimova1 , V. Kim1 , Z. Syrymbet Kyzy1
1
K AZAKH RESEARCH INSTITUTE OF ONCOLOGY AND RADIOLOGY, Almaty,
Kazakhstan

Conclusions: Our study have demonstrated superior freedom from biochemical failure (FFBF) with adjuvant radiotherapy compared to salvage radiotherapy treatment, in keeping with results from clinical trials and the incidence ofgrade 3 and 4 acute/late toxicities are within acceptable limits. Currently ourpatients are enrolled into the RADICALS trial which is also evaluating the roleof androgen deprivation therapy in this setting.

Purpose: To report the results of a randomized trial on primary radiotherapy
in combination with androgen deprivation in patients with high-risk prostatecancer.
Materials: Between January 2004 and January 2009, 90 patients with locallyadvanced prostate cancer (stage cT3-4 cN0-1 cM0) [age range 52-69, median 60.5 years] were randomized between the two arms: in the 1st group 47
patients (52.2%) received neo-adjuvant androgen deprivation (zoladex on day
1 every 28 days and kalumid daily) for 3 months followed by radiotherapy. The
2nd group included 43 patients (47.8%) underwent concomitant radiotherapy
and androgen deprivation with kalumid daily. 3D-conformal radiotherapy wasdelivered to a median dose of 70 Gy in 35 fractions. After treatment completion all patients continued hormone therapy. Before treatment PSA was 25.4
and 26.7 ng/ml in group 1 and 2, respectively.
Results: Median follow-up was 57.5 and 53.1 months in group 1 and 2, respectively. Three-year biochemical progression-free survival was 100% in
both groups; 5-year overall survival was 71.9% in group 1 versus 63.8% ingroup 2. Grade ≤ 2 genitourinary and gastrointestinal toxicity were observedin 81 and 76 patients, respectively.
Conclusions: Primary radiotherapy and hormone therapy resulted in thegood outcome with tolerable and mild toxicity. Neoadjuvant androgen deprivation with zoladex and kalumid appeared to be more effective in patientswith high-risk prostate cancer.

1032 poster
MLN8054, A NOVEL INHIBITOR OF AURORA KINASE A SENSITIZES ANDROGEN-RESISTANT PROSTATE CANCER MODELS TO
RADIATION
L. Moretti1 23 , K. Niermann2 34 , S. Schleicher5 , K. W. Kim5 , P. Kopsombut5 ,D. K. Jung5 , B. Lu2 34
1
I NSTITUT J. B ORDET, Department of Radiation Oncology, Brussels,
Belgium
2
VANDERBILT-I NGRAM C ANCER C ENTER, Nashville, USA
3
VANDERBILT U NIVERSITY M EDICAL C ENTER, Department of Radiation
Oncology, Nashville, Tennessee, USA
4
VANDERBILT S CHOOL OF M EDICINE, Nashville, Tennessee, USA
5
VANDERBILT S CHOOL OF M EDICINE, Department of Radiation Oncology,
Nashville, Tennessee, USA
Purpose: Despite multi-modality treatment, the existence of androgenresistant subpopulations in prostate cancer poses an important therapeutic
problem. Expression of Aurora kinase A (AURKA) is increased in humanprostate cancer and has been correlated with poor prognosis and cancer
progression. Because MLN8054, a specific small-molecule inhibitor of AURKA has been shown to delay G2/M progression and to inhibit proliferation inhuman prostate carcinoma, we evaluated MLN8054 as a potential radiosensitizer in androgen-insensitive prostate cancer models.
Materials: PC3 and DU145 androgen-insensitive prostate cancer cells weretreated with various doses of MLN8054 for various time points to determine
the cell cycle conditions that yielded maximal increase in G2/M phase andpolyploidy cells. To assess DNA damage, γ -H2AX phosphorylation wasquantified by immunofluorescence for cells grown under optimal radiosensitizing conditions and subjected to either 0 (control) or 5 Gy radiation. Clonogenic assays of these cells were performed to determine radiosensitivity. A
hind limb prostate cancer mouse model was used to study tumor growth delay in vivo. Using immunohistochemistry, tumor sections from prostate cancer xenografts were analyzed for cell proliferation (Ki67), angiogenesis (VonWillebrandt), and apoptosis (caspase-3).
Results: We found that inhibition of AURKA by MLN8054 sensitized prostatecancer cell lines, as determined by clonogenic assay (PC3: DER=1.37,
p=0.02; DU145: DER=1.27, p=0.019). In both cell lines, 1µM MLN8054 induced significant G2/M accumulation, polyploidy, and DNA damage (PC3:
100% vs. 76%, p=0.035; DU145: 100% vs. 69.33%, p=0.034). In vivo, theaddition of MLN8054 to radiation significantly increased tumor growth delay
and apoptosis, with reduction in cell proliferation and vascular density.
Conclusions: MLN8054, a novel small-molecule AURKA inhibitor enhances
the cytotoxic effects of radiation on prostate cancer and its vasculature both invitro and in vivo, and extends tumor growth delay. Our findings warrant clinical
trials to determine the full potential of this combination therapy in patients withprostate cancer.

pN+ patients. The prescribed median dose was 66,6 Gy (range 50-70) to theprostate bed and 45-50.4 Gy to the regional nodes.
Results: Median follow-up time was 57 months (range 5.2 - 138). Biochemical relapse occurred in 29 patients (13.5%), loco-regional relapse in 7 (2.9%)
and distant metastasis in 20 (9.3%). Six patients (2.8%) died from systemic
progression of disease, 7 (6%) from other causes and 4 (1.8%) because of
second cancer. Biochemical relapse-free survival was 90% at 3 years, 80%
at 5 years. Loco-regional relapse-free survival was 100% at 3 years, 90%
at 5 years . Distant metastasis-free survival was 95% at 3 years, 90% at 5
years . Overall survival was 95% at 3 years, 90% at 5 years. Different risk
factors (stage, GS, preoperative and pre-RT PSA levels, margins status, HT)were evaluated in univariate and multivariate analysis. In multivariate analyses preoperative (p =0.001) and pre-RT PSA levels (p =0.001) and stages
T3b (p=0.032) and T4 (p=0.001) were independent predictors of biochemical
relapse. Although not significative, HT has a protective role when administered for more than 402 days (HR = 0.45; 95% CI 0.14-1.43). Pre-RT PSA
value (p=0.002) and stage T4 (p=0.046) were independent predictors of distant metastasis. Acute ≥ grade II GU (genitourinary) and GI (gastrointestinal)
toxicity occurred in 21% and 43% of cases respectively. Thirteen (6%) patients developed late grade III GU complication. Adjuvant RT had no adverse
effect on the urinary continence.
Conclusions: Postoperative high dose (66-70 Gy) conformal radiotherapy inpatients with high risk pathological features was associated with a low risk ofbiochemical and local recurrence accomplished with minimal morbidity.
1035 poster

1034 poster

1036 poster

POSTOPERATIVE HIGH DOSE CONFORMAL RADIOTHERAPY IN
PATIENTS WITH HIGH RISK PROSTATE CANCER
R. Bellavita1 , M. Massetti1 , F. Arcidiacono1 , V. Radicchia1 , F. Matrone1 , G.
Montesi1 , I. Abraha2 , C. Aristei3
1
U NIVERSITY OF P ERUGIA, Department of Radiation Oncology, Perugia,
Italy
2
U NIVERSITY OF P ERUGIA, Epidemiology, Perugia, Italy
3
U NIVERSITY OF P ERUGIA - S.M. DELLA M ISERICORDIA H OSPITAL,
Department of Radiation Oncology, Perugia, Italy

PROPHYLACTIC BREAST IRRADIATION TO PREVENT ANTIANDROGEN (BICALUTAMIDE) INDUCED GYNAECOMASTIA IN
LOCALLY ADVANCED PROSTATE CANCER
R. Dandamudi1 , A. Samanci1
1
N EW C ROSS H OSPITAL , D EANESLY C ENTRE, 1st Clinical Oncology
Department, Wolverhampton, United Kingdom

Purpose: To evaluate treatment outcome and toxicity of three-dimensional
conformal radiotherapy (3D-CRT) after radical prostatectomy (RP).
Materials: From August 1998 to December 2007, 214 patients with positive
resection margin and/or pT3-4 or N+ prostatic adenocarcinoma underwent
postoperative 3D-CRT. Patient characteristics were as follows: median age
65 years (range 51-77); stage pT2N0 in 48 patients (22%), pT3aN0 in 41
patients (19%), pT3bN0 in 76 (36%), pT4N0 in 17 (8%), N+ in 32 (15%); positive margins in 158 patients (74%); Gleason score (GS) 2-6 in 43 patients(20%), 7 in 91 (42%), and 8-10 in 80 (37%). Median preoperative and pre RT
PSA values were 7.93 ng/ml (range 0.57-166) and 0.05 ng/ml (range 0.0026,39) respectively. Median time from surgery to RT was 5.3 months (range
1.2-8.8); 150 patients (70%) received hormonal therapy (HT) with LHRH analogue and/or antiandrogen. 3D-CRT was delivered with 15-18 MV photons
to the tumor bed in 182 patients (85%) and to the regional nodes in the 32

Purpose: To prospectively evaluate the efficacy of prophylactic breast irradiation to prevent Anti-Androgen (bicalutamide) induced Gynaecomastia in
locally advanced Prostate cancer patients in our institute and compare theresults with the published data.
Materials: Between January 2006 to December 2008, sixty five patients had
prophylactic breast irradiation before commencing long term (≥ 2 years) Bicalutamide (150mg/day) monotherapy for locally advanced adenocarcinomaof the prostate. The median age was 67 years (range 47-81). Sixty patients(92.3%) received single dose of 12Gy, three (4.7%) received 8Gy and twopatients (3%) received 15Gy delivered by electron energy (6-12 MeV). The
average field size was 4 cm circle (range 3.5 - 8cm) centered around the nipple and areola. Baseline and 3-monthly follow up assessment was done byphysical examination and direct questioning. Gynaecomastia and radiation
dermatitis scoring was done according to Common Toxicity Criteria (CTC).
Results: At three month follow up, none of the patients developed Gynaecomastia and 0% had Grade 3 or 4 acute radiation dermatitis. At the endof 12 month follow-up, all the sixty five patients remained on bicalutamide.

S 387

Of these, fifty two patients (80 %) had Grade 0, eight patients (12.3%) had
Grade 1 and five patients (7.7%) had Grade 2 Gynaecomastia. No long term
radiation dermatitis noted.
Conclusions: Prophylactic breast radiotherapy to prevent bicalutamide induced Gynaecomastia is effective as shown in the published literature andour results are encouraging.
1037 poster
PROSTATE BRACHYTHERAPY INDUCED SECOND PRIMARYCANCER: A COMPETITIVE RISK ANALYSIS.
M. van Vulpen1 , M. Schaapveld2 , K. Hinnen3 , H. van der Poel4 , I. vanOort5 , J. Roermund6 , J. J. Battermann7 , S. Franken7 , U. van der Heide7 , E.
Monninkhof8
1
U.M.C. U TRECHT, I Radiotherapy, Utrecht, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Epidemiology, Amsterdam, Netherlands
3
U NIVERSITY M EDICAL C ENTER U TRECHT, Radiotherapy, Utrecht,
Netherlands
4
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Urology, Amsterdam, Netherlands
5
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Urology, Nijmegen,
Netherlands
6
U.M.C. U TRECHT, Urology, Utrecht, Netherlands
7
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands
8
U.M.C. U TRECHT, Epidemiology, Utrecht, Netherlands
Purpose: To assess the risk of second primary cancers (SPC) after I-125
prostate cancer brachytherapy compared to prostatectomy and the general
population.
Materials: In a cohort consisting of 1,888 patients, who received either
brachytherapy (1,187; 63%) or prostatectomy (701; 37%), SPC incidenceswere retrieved through a query in the Dutch Association of Comprehensive
Cancer Centres tumour registry. Standardized incidence rates (SIR) and absolute excess risk (AER), the excess incidences of SPC per 10,000 personyears, were calculated for comparison. The effect of brachytherapy on SPC
incidence was quantified in multivariate Cox-regression analysis adjusted forage.
Results: In total, 223 patients were diagnosed with a SPC, 136 patients inthe brachytherapy group and 87 patients in the prostatectomy group. The SIR(95% confidence interval) for all malignancies, bladder cancer and rectal cancer were respectively 0.94 (0.78-1.12), 1.69 (0.98-2.70) and 0.90 (0.41-1.72)
for brachytherapy and 1.04 (0.83-2.28), 1.82 (0.87-3.35) and 1.50 (0.68-2.85)
for prostatectomy. The risk of SPC of the bladder was significantly increased
after brachytherapy for patients aged ≤ 60 years, SIR 5.84 (2.14-12.71); AER
24.03 and in the first 4 years of follow-up, SIR 2.14 (1.03-3.94); AER 12.24.
Adjusted for age, the hazard ratio for brachytherapy versus prostatectomy
was 0.87 (95% CI 0.64-1.18) for all SPC’s, 0.96 (p=0.924) for gastrointestinal
SPC’s and 1.13 (p=0.754) for urinary tract SPC’s.
Conclusions: The SPC incidence rate after brachytherapy is comparable toprostatectomy as well as the general population. The higher than expected
incidences of bladder SPC after brachytherapy in the first 4 years of follow-up
may be the effect of lead-time or screening bias. Adjusted for age, no difference in SPC risk exists between brachytherapy and prostatectomy patients.
1038 poster
PROSTATE BRACHYTHERAPY WITH OR WITHOUT ADJUVANT ADT
IN INTERMEDIATE PROSTATE CANCER: STUDY PROTOCOL
K. Miki1 , K. Masahito1 , M. Aoki2
1
J IKEI U NIVERSITY S CHOOL OF M EDICINE, Department of Urology,
Minato-ku, Japan
2
J IKEI U NIVERSITY S CHOOL OF M EDICINE, Department of Radiation
Oncology, Minato-ku, Japan
Purpose: The optimal protocol for 125 I-transperineal prostatic brachytherapy (TPPB) in intermediate-risk prostate cancer (PCa) patients remains controversial. Data on the efficacy of combining androgen-deprivation therapy(ADT) with 125 I-TPPB in this group remain limited and consequently theguidelines of the American Brachytherapy Society (ABS) provide no firm recommendations.
Materials: Seed and Hormone for Intermediate-risk Prostate Cancer (SHIP)
0804 is a phase III, multicenter, randomized, controlled study that will investigate the impact of adjuvant ADT following neoadjuvant ADT and 125 I-TPPB.
Prior to the end of March, 2011, a total of 420 patients with intermediaterisk, localized PCa will be enrolled and randomized to one of two treatment
arms. These patients will be recruited from 20 institutions, all of which havebroad experience of 125 I-TPPB. Pathological slides will be centrally reviewed
to confirm patient eligibility. The patients will initially undergo 3-month ADT
prior to 125 I-TPPB. Those randomly assigned to adjuvant therapy will subsequently undergo 9 months of adjuvant ADT. All participants will be assessedat baseline and at the following intervals: every 3 months for the first 24
months following 125 I-TPPB, every 6 months during the 24- to 60-month post-S 388P ROSTATE CANCERP ROSTATE CANCER

125

I-TPPB interval, annually between 60 and 84 months post-125 I-TPPB, andon the 10th anniversary of treatment. The primary endpoint is biochemical progression-free survival (BPFS). Secondary endpoints are overall survival (OS), clinical progression-free survival, disease-specific survival, salvage therapy non-adaptive interval, acceptability (assessed using the international prostate symptom score [IPSS]), quality of life (QOL) evaluation, andadverse events. In the correlative study (SHIP36B), we also evaluate biopsy
results at 36 months following treatment to examine the relationship between
the results and the eventual recurrence after completion of radiotherapy
Results:
Conclusions: These two multicenter trials (SHIP0804 & SHIP36B) are expected to provide crucial data regarding the efficacy, acceptability and safetyof adjuvant ADT. SHIP36B will also provide important information about
the prognostic implications of PSA levels in intermediate-risk PCa patientstreated with 125 I-TPPB.

months) concerning QL outcomes of the pts treated with IB.
Materials: From March 2005, we evaluated a consecutive series of 228 pts
treated with IB for LPC. All pts were requested to fill a self-filled QL questionnaire a week before, one month, 6 months, and yearly after IB (until 5
years). The questionnaire (listing 64 items) derived from a validated instrument used in the first published study. The items identify the following QL
subscales: physical well-being (PHY), psychological well-being (PSY), relational life (REL), physical autonomy (POW), rectal (REC), urinary (URI) andsexual functioning (SEX). The subscales were based on 6, 5, 4, 6, 6, 12,
16 items respectively. Differences between the pre- and post-treatment subscales value means were statistically analyzed by one-way variance analysis.
Results: The mean subscale scores observed before and after treatment are
showed in the table (in bold values which statistically differ from baseline).

1039 poster
PSA RESPONSE TO NEOADJUVANT ANDROGEN SUPPRESSIONTHERAPY PRIOR TO HIGH DOSE RATE BRACHYTHERAPY COMBINED WITH HYPOFRACTIONATED EXTERNAL BEAM RADIATIONTHERAPY PREDICTS BIOCHEMICAL PROGRESSION FREE SURVIVAL IN LOCALIZED HIGH RISK PROSTATE CANCER
M. Aoki1 , K. Miki2 , K. Masahito2 , J. Yamamoto2 , S. Takaki1 , M. Kobayashi1 ,C. Kanehira1
1
J IKEI U NIVERSITY S CHOOL OF M EDICINE, Department of Radiation
Oncology, Minato-ku, Japan
2
J IKEI U NIVERSITY S CHOOL OF M EDICINE, Urology, Minato-ku, Japan
Purpose: High dose rate (HDR) brachytherapy combined with externalbeam radiation therapy (EBRT), neoadjuvant androgen suppression therapy(NAST) and adjuvant androgen suppression therapy (AAST) (Tri-modality)
have been used to treat localized high risk prostate cancer. To define prognostic factors of biochemical relapse free survival (bRFS), an analysis of patients treated with Tri-modality were performed.
Materials: Between May 2005 and July 2007, 74 high-risk prostate cancer patients (D’Amico classification) were treated with NAST prior to HDRbrachytherapy combined with hypofractionated EBRT. Among 74 patients, 72
patients (97%) had completed AAST for 24 months after whole radiotherapy.
The median age was 68 years (range, 59-81). The median initial PSA was
23.5 ng/ml (range, 3.9-192). The median Gleason score was 8 (GS 6/7/8/9/10: 6/18/25/22/1). The median follow up was 48 months (range, 40-64). The
median NAST was 8 months (range,1-18). The median AAST was 24 months(range, 3-24). All patients had been treated with HDR brachytherapy (PTV:
5Gy, 6Gy, 2fx/day) and hypofractionated EBRT (45Gy : 3Gy5fx/3weeks). Hypofractionated EBRT was performed 1weeks after HDR brachytherapy. 48
patients were given total androgen suppression as NAST.
Results: With a median follow up of 48 months, bRFS of all patients was
83.1%. On multivariate analysis of factors predicting bRFS, only Gleason
score was significant (p=0.03) and Pre-HDR PSA tended to be significant
predictor (p=0.059), but age and initial PSA were not significant respectively(p=0.24, 0.47). Patients in the Pre-HDR PSA0.1 group have significantly improved bRFS compared to patients in the Pre-HDR PSA0.1 group (93.7%
vs. 67.8%, p=0.026). On multivariate analysis of factors predicting Pre-HDR
PSA level, the term of NAST was significant (p=0.01) and other factors including age, initial PSA, Gleason score were not significant respectively (p=0.08,
0.35, 0.26).
Conclusions: For high-risk prostate cancer patients treated with Tri-modality(NAST, HDR plus EBRT, AAST), Gleason score and Pre-HDR PSA were important prognostic factors (p=0.03, 0.059 respectively). Patients in the PreHDR PSA0.1 group have significantly improved bRFS compared to patientsin the Pre-HDR PSA0.1 group (p=0.026). A further study is needed to confirm
the importance of Pre-HDR PSA in Tri-modality treatment.
1040 poster
QUALITY OF LIFE (QL) OF PATIENTS (PTS) TREATED WITH
INTERSTITIAL BRACHYTHERAPY (IB) FOR LOCALIZED PROSTATECANCER (LPC).
O. Caffo1 , G. Fellin2 , S. Mussari2 , C. Divan3 , F. Coccarelli3 , F. Ziglio4
1
O SPEDALE S ANTA C HIARA, Medical Oncology Department, Trento, Italy
2
O SPEDALE S ANTA C HIARA, Radiotherapy Department, Trento, Italy
3
O SPEDALE S ANTA C HIARA, Urology, Trento, Italy
4
O SPEDALE S ANTA C HIARA, Medical Physics, Trento, Italy
Purpose: Today, IB is considered as a therapeutic option for LPC and thistherapy has been offered to selected patients (pts) in our Hospital from 2000.
Since IB is usually perceived (by both pts and physicians) as a treatment able
to produce a low impact on pts QL, we have evaluated this outcome by two
prospective studies. The results of the first, specifically devoted to IB pts,
were previously published (IJROBP 66: 3137, 2006). The second (started
in 2006) attempted to evaluate QL of pts with LPC treated with different local treatments. The present report shows the preliminary results (until 24

Conclusions: Our data confirms that IB negatively impacts on physical functions (rectal, urinary and sexual) within the first two years after the implant.
We are waiting the analysis of the data at 3,4, and 5 years to assess thelong-term QL outcomes.
1041 poster
SIMULTANEOUS INTEGRATED BOOST-IMRT WITH SERIAL TOMOTHERAPY VS 3DIMENSIONAL-CONFORMAL HIGH-DOSE RT IN
PROSTATE CANCER
A. Papaleo1 , A. Leone2 , D. Russo2 , E. Cavalera2 , M. G. Natali1 , M.
Santantonio2
1
O SPEDALE V ITO FAZZI, Division of Medical Physics in Radiation Oncology,
Lecce, Italy
2
O SPEDALE V ITO FAZZI, Department of Radiation Oncology, Lecce, Italy
Purpose: The aim of this study was to compare the dose coverage of planning and clinical target volume and organs-at-risk (rectum, bladder and femurs) and to evaluate quantitatively the clinical benefits of using SIB-IMRTvs 3D-CRT in treating localized prostate cancer, based on the acute and lateadverse events frequency.
Materials: Between November 2007 and February 2009, at the Operative
Unit of Radiotherapy of V. Fazzi Hospital of Lecce, during the implementation of dynamic-arc-IMRT with NomoStat System®for Serial Tomotherapy,
23 localized prostate cancer patients were selected for this comparative
study.Twelve patients were treated with 3D-CRT to 76 Gy in 38 fraction to
prostate (60 Gy in 30 fraction to seminal vesicles). The SIB-IMRT for 11
patients plans were designed to deliver 78,5 Gy in 35 fractions (2,24 Gy/fr)
to the prostate while simultaneously delivering 66,5 Gy in 35 fractions (1,9Gy/fr.) to seminal vesicles.The doses to the bladder and to the rectum were
evaluated based on dose-volume histograms of the entire bladder/rectal volume. The association of these dose parameters with acute and late toxicity
was conducted. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, was used to score toxicity. During a 12months median follow-up (range,6-18 mesi), the periodical PSA score andthe erectile dysfunction were investigated.
Results: The average values for the percent volume that received at least
95%of the prescription dose (V95), the target volume covered by 100% of theprescription dose ( D100%) and the conformity index of the PTV were 99,3%,
97,8% and 0,9 for SIB-IMRT, 95%, 68,8%, and 0,65 for the 3D-RT, respectively.The mean dose to the bladder was 38,8 Gy (range, 34-55) and 26.8 Gy(range, 22-35) with 3D-CRT and IMRT, respectively (limit of dose considered:
V50<30%). The volume of rectum receiving 70 Gy or more (V70) was 18%
for SIB-IMRT and 33% for the 3D-RT, respectively (V45<30%). The mean
femur doses with SIB-IMRT were approximately 30% lower than obtainedwith 3D-CRT.The must common acute grade 2 events were cystitis (23% vs
36,7%) and urinary urgency/frequency (15% vs 26,7%). Only one case of
grade 3 rectal bleeding was observed in conventional treatment.At a medianfollow-up of 12 months, late toxicity was uncommon for SIB-IMRT (1 pts withurinary urgency vs 5 pts with erectile dysfunction and urinary urgency and 2
pts with chronic pelvic pain). The PSA relapse-free survival provides a good
indication of the efficacy of RT, but did not correlate with any of the dosimetricparameters examined.
Conclusions: The IMRT with Serial Tomotherapy achieved the must conformal dose distribution to the PTV, in return for a larger, but acceptable, dose
inhomogeneity and markedly reduced doses to the critical structures for mostof the cases considered in this study. The SIB-IMRT, moreover, was welltolerated in this series, with low rates of Grade 2 or greater acute and late
toxicity. The interim results at our institution indicate that SIB-IMRT is feasible and effective, because offers an accelerated approach to treating low- tointermediate-risk disease and minimize the volume of normal tissue treatedto high dose levels. Additional follow-up, however, is necessary to fully define the long-term toxicity, the disease-free-survival, the overall survival anddevelopment of second cancers.
1042 poster
SURVIVAL AND ACUTE TOXICITY AFTER PROSTATE LDR
BRACHYTHERAPYIN
ELDERLY
PATIENT:ASINGLEINSTITUTIONAL EXPERIENCE
1
1
2
1
C. Chiumento , A. Fiorentino , P. Pedicini , S. Clemente , V. Fusco2
1
IRCCS/CROB, Department of Radiation Oncology, Rionero in Vulture,
Italy
2
C ENTRO DI R IFERIMENTO O NCOLOGICO DELLA B ASILICATA, Departmentof Radiation Oncology, Rionero in Vulture (PZ), Italy

S 389

1044 poster
THE IMPACT OF ANTI-COAGULANTS AND STATINS ON PROSTATECANCER
M. Alizadeh1 , M. P. Sylvestre2 , T. Zilli1 , T. V. Nguyen Huynh1 , J. P. Guay1 , J.
P. Bahary1 , D. Taussky1
1
CHUM - C AMPUS N OTRE -DAME, Département de Radio-Oncologie,
Montréal, Canada
2
CRCHUM - C ENTRE DE R ECHERCHE DU C ENTRE H OSPITALIER DE
L’U NIVERSITÉ DE M ONTRÉAL , Montréal, Canada

Purpose: To determine the acute genitourinary (GU) toxicity and biochemicaldisease free survival (b DFS) rate after I125 permanent prostate brachytherapy implant (LDR-BRT) in elderly patients (pts) affected by prostate cancer.
Materials: Pts with diagnosis of prostate cancer, aged > 65 yrs (range 6586) were treated in our Institution and were retrospectively evaluated. All patients received LDR-BRT as monotherapy ; the prescribe dose was 145 Gy toprostate. Patients were stratified into recurrence risk group according to the
National Comprehensive Cancer Network (NCCN). Biochemical failure wasdefined according to the ASTRO criteria. Acute toxicity was scored according to RTOG Scale. b-DFS was calculated from implant date to biochemicalrecurrence.
Results: A total of 81 pts were treated between June 2003 and December
2008 , 64 pts with low-risk (79%) ,12 pts with intermediate-risk (14%) and 5
pts with high risk (6%) prostate cancer were treated by LDR-BRT monotherapy . Median age was 79 years (range 65- 86). With a median follow-up of
49 months (24-90), the b-NED survival rate was 88%, with a global actuarial
5-year b-DFS of 86%. Acute Grade 3 GU toxicity was observed in 3 pts (4%).
Conclusions: Our data suggest that LDR-BRT was effective and safe as
monotherapy in elderly pts affected by prostate cancer

Purpose: Statins and anti-coagulants (AC) are both associated with a lessaggressive prostate cancer and a better outcome after treatment for localized
prostate cancer. Results of these studies might be confounded by the factthat patients might often take both medications at the same time. We analyzed their respective influence on prostate cancer aggressiveness at initialdiagnosis.
Materials: We analyzed 402 patients treated with either external beam radiation therapy or brachytherapy for either low (N=155), intermediate (N=152) or
high-risk (N=95) localized prostate cancer. Statin and AC (anti-platelet therapy or warfarin) use were noted before treatment. Univariate and multivariate
logistic regression analysis were used to investigate an association between
these drug classes and National Comprehensive Cancer Network (NCCN)
risk class, PSA level, Gleason scores and T-stage. We tested whether theconcomitant use of Statin and AC had a different effect than that of either ACor statin use alone.
Results: 185 patients (46%) were taking statins and 162 (40.3%) AC. 118(29.4%) patients used both. There was a strong association between theuse of both (6.9 95% CI, 4.5, 10.9; p<0.0001). In the univariate analysis,
statin users were less likely to have a PSA >20 ng/ml (OR 0.45, 95%CI, 0.22,
0.88; p=0.0202). AC use was associated with risk group (p<0.0001), PSA(p=0.009) and Gleason score (p=0.002). In the multivariate analysis, statin
use was not associated with risk group (p=0.3074), but age (p<0.0001) andAC use was (p=0.0117). The use of AC was associated with double the riskof being in either the intermediate and high risk group compared to the lowrisk group.
Conclusions: The influence of AC on prostate cancer aggressiveness ismuch more important than the one of statins which might be limited to PSA
only. This might have confounded previously published studies that analyzed
statin use only.

1043 poster

1045 poster

THE
CONFORMATIONAL
RADIOTHERAPYIN
LOCALIZEDPROSTATE CANCERS. EXPERIENCE OF RADIOTHERAPY ONCOLOGY DEPARTMENT
A. MESSAOUD1 , K. Boualga2
1
C ENTRE A NTI -C ANCER, Radiotherapy Oncology, Blida, Algeria
2
C ENTRE A NTI -C ANCER, Blida, Algeria

THE PROGNOSTIC VALUE OF EXPRESSION OF HIF 1, VEGF-A
AND EGFR IN PROSTATE CANCER FOR INTERMEDIATE-RISK PATIENT TREATED WITH RADIATION THERAPY WITH OR WITHOUT
ANDROGEN DEPRIVATION THERAPY.
J. C. Tille1 , D. C. Weber2 , K. Hammad1 , P. Granger1 , J. F. Egger1 , L.
Rubbia-Brandt1 , R. Miralbell3
1
G ENEVA U NIVERSITY H OSPITAL, Pathology and Medical Biology, Geneva,
Switzerland
2
G ENEVA U NIVERSITY H OSPITAL, Radiation Oncology, Geneva, Switzerland
3
G ENEVA U NIVERSITY H OSPITAL, Radiation Oncology Department, Geneva,
Switzerland

Purpose: The conformational radiotherapy is used in first intention in locatedcancers of the prostate,it is curative treatment wich preserves a certaine quality of life and has the potentiel to reduce considerably the dose delivered tothe healthy bodies,to thus decrease the acute and late effects of irradiation
generally transitory.This study aimed to describe the therapeutic methods ,toevaluate the preliminary results in terms of biochemical control and toxicity.
Materials: Between january 2008 and january 2009,34 patients ,of median69 years affected of localized cancer of the prostate were treated in our department by a conformational radiotherapy.The tumors were stratified according to the three prognostic groups of AMICO : favourable ( 12%),intermidiary(59%),unfavourable (29%).All the patients received a conformational radiotherapy prostate of total dose of 72 Gy;associated with a androgenic deprivation.
Results: The duration of the therapeutic follow-up post was 24 months.At theend of the treatment ,the independent factor of evaluation was the biologicalfactor : rate of PSA.The rate of PSA was standarized at the totality of thepatients.Clinical examinations;radiological and biological (PSA) were carriedout at our patients (100%),did not show any anomaly.As regards toxicity,there
is a better tolerance compared to the conventional radiotherapy since the side
effects were from G1 and G2,reversible after a medical care.
Conclusions: This conformational radiotherapy showed a benefit as regards
results to the former patients treated by conventional radiotherapy :- not of toxicity G3,G4-normalization of the biological criteria related to an good tumoricide answerThe conformational technique should be essential like a standard
in radiotherapy with curative aim of the prostate cancer,appears similar to thatof surgery some is the stage of the disease.Survival and the complications require a follow-up of long life and through analysis.

Purpose: Androgens stimulate the production of hypoxia-inducible factor(HIF1α) and ultimately vascular endothelial growth factor (VEGF-A). Additionally, epithelial growth factor (EGF) mediates HIF1α production. This study assesses the prognostic relation between HIF1α, VEGF-A and EGFR expression in diagnostic samples of patients with intermediate risk prostate cancer
treated with radiation therapy, with or without androgen deprivation therapy(ADT).
Materials: Between 1994 and 2004, 70 prostate cancer patients (meanage, 69.4±6.5), with intermediate risk localized prostate cancer (mean PSA,
13.5±3.1), were treated with radiation therapy (median dose, 74 Gy). Thirtynine (55.7%) patients received ADT (median duration, 6 months; range, 024). The prognostic significance of HIF1α, VEGFR and EGFR expression byimmunochemistry on diagnostic biopsies was assessed.
Results: Median follow-up was 98.7 months. On univariate analysis, high expression of EGFR, but not HIF1α or VEGF-A, was a significant (p=0.027) predictor of a shorter time to biological failure. The 8-year biological progressionfree survival (bPFS) was 50%, 70.5% and 91.7% for patients with strong,weak and no EGFR expression, respectively. A trend toward significance(p=0.08) was observed between EGFR expression and a high Gleason score.
After exclusive RT, the 8-year bPFS was 81.6% and 51.3% for patients withnegative and positive EGFR staining, respectively (p=0.14). After RT combined with ADT, the 8-year bPFS was 100% and 68.4% for patients with negative and positive EGFR staining, respectively (p=0.18).
Conclusions: Our study suggests that for patients with intermediate risk
prostate cancer treated with radiation therapy, high expression of EGFR in
diagnostic biopsies was significantly associated with a shorter time to biochemical failure. ADT administration did not improve the biological outcomeof patients with EGFR positive tumors.

S 390R ECTAL CANCERR ECTAL CANCER

1046 poster

but we do not have complete control over the tumor dose and the overdoseof normal tissues; therefore we introduced dose-volume parameters.
Conclusions: Thus, intracavitary therapy for anal cancer is the optimal variant of radiation therapy. It is the optimal treatment method with a minimalradiation load for surrounding tissues and critical organs.

URETHRAL STRICTURE AS A COMPLICATION OF HIGH DOSE
RATE BRACHYTHERAPY FOR PROSTATE CANCER
T. Lo1 , A. Vanni2 , P. Cronin1
1
L AHEY C LINIC, Radiation Oncology, Burlington, USA
2
L AHEY C LINIC, Urology, Burlington, USA
Purpose: Urethral stricture is one of the well-known complications of treatment for prostate cancer, regardless of the particular type of therapeuticmodality. The goal of our study was to determine the incidence, timing, andoutcomes of urethral strictures in the cohort of patients undergoing high dose
rate (HDR) brachytherapy for prostate cancer.
Materials: A retrospective review of 360 consecutive patients undergoing
HDR brachytherapy at our institution from 1997-2009 was performed. Amongthe 360 patients, 158 patients had high risk prostate cancer, 187 patients hadintermediate risk prostate cancer, and 15 patients had low risk prostate cancer. Three hundred thirty-six patients (93%) received neo-adjuvant hormone
therapy. The HDR protocol typically called for 3 treatment sessions over a
period of 24 hours in 2 days. A single radioactive iridium-192 source wasused with a nominal activity of 370 GBq. The peripheral minimum dose to
the prostate gland per session was 6 Gy. All patients received supplementary
external beam radiation therapy after completion of the brachytherapy procedure, and external beam dose ranged from 45 Gy to 50.4 Gy (median 50 Gy)
using conventional fractionation schemes. Twenty patients were lost to follow
up or had insufficient follow up and were excluded from analysis. All urethralstrictures were diagnosed cystoscopically. Patient demographics, operative,
and postoperative data were reviewed.
Results: Three hundred thirty-nine patients were analyzed with an overall
survival rate of 98.6%, at a mean follow-up of 55 months. Two patients diedfrom metastasis and 2 other patients died from unrelated causes. Two hundred eighty-two patients (83.1%) are currently free of disease or biochemical
progression. Twenty-two patients (6.5%) have developed urethral strictures
to-date. The median time between radiation therapy and the diagnosis of urethral stricture was 4 years (range 1-8 years), with nearly all strictures locatedin the bulbomembranous urethra. At last follow-up, 2 patients had a stable,
patent urethra. One of these patients was managed with single balloon dilation, while the other patient underwent urethroplasty after failing endoscopic
management. The remaining 20 patients did not have a stable patent urethra. Nine (41%) of these patients required a urethral dilation schedule, and 3
patients (14%) needed either suprapubic tube or urethral catheter drainage.
Five patients (23%) have required multiple endoscopic procedures or dilations(range 2-7), while 3 patients (14%) have required dilation at last follow-up.
Conclusions: Urethral stricture incidence from HDR brachytherapy in combination with external beam radiotherapy for clinically localized prostate cancer
is 6.5%. Although radiation induced urethral stricture has a relatively low incidence, it could result in significant morbidity for the patient. Short term data
supports HDR brachytherapy as an equivalent therapy for localized prostatecancer, but should be limited to high volume centers to minimize refractory
urethral stricture complications.
1047 poster
VOLUMETO-DOSIMETORIC INFLUENCE OF ROV ON PTV AND CTV
IN THE TREATMENT OF THE PROSTATE.
H. Nagano1 , M. Kato2 , H. HASHIMOTO1 , T. SHIMO2
1

C HIGASAKI TOKUSHUKAI M EDICAL C ENTER, Department of Radiation
Oncology, Chigasaki, Kanagawa, Japan
2
TOKYO W EST TOKASHUKAI H OSPITAL, Department of Radiology, Tokyo,
Japan
Purpose: One of the great difficulties in the radiation treatment of the prostate
carcinoma is rectum override volume (ROV) over planning target volume(PTV). Intensity-modulated radiation therapy (IMRT) has been contributing
to reduce radiation doses to this volume, however, little is known how ROV
works on dosimetric parameters of PTV and CTV. We plotted some parameters such as D1, D50, D95 and D99 of PTV and CTV against ROV andanalyzed the relationships using linear regression fitting.
Materials: Fifty seven consecutive patients were analyzed (T1-2 35 cases,
T3 22 cases). Prescription dose for PTV was 72 Gy as minimum dose, andfor CTV (prostate in T1-2 cases, prostate and seminal vesicle in T3 cases) 76
Gy as uniform dose in 38 fractions. Seven beams and fifty segments set-up
were employed with the step-and-shoot technique. Direct machine parameter
optimization was done on Pinnacle3 . CRAN’s R free software was used forlinear fitting computations. D1, D50, D95 and D99 of PTV and CTV were
defined as responses of a linear predictor of ROV.
Results: Regression coefficients or effects for D1, D50, D95 and D99 of
PTV were 0.086 (p=0.135), -0.062 (p=0.018), -0.307 (P<0.001) and -0.516(p<0.001), respectively. Those values of CTV were 0.040 (p=0.091), -0.082(p=0.001), -0.152 (P<0.001) and -0.167 (p<0.001). Intercepts for D1, D50,
D95 and D99 of PTV were 76.65 Gy, 74.81 Gy, 71.91 Gy 70.97 Gy, respectively. Those values of CTV were 76.42 Gy, 76.12Gy, 75.68 Gy and 75.17 Gy.
Average value of ROV was 4.7 ml (SD = 2.6 ml).

1049 poster
ADAPTIVE IMAGE-GUIDED TOMOTHERAPY CONCOMITANT TOCHEMOTHERAPY IN RECTAL CANCER: EARLY CLINICAL EXPERIENCE
N. Slim1 , P. Passoni1 , C. Fiorino2 , E. Maggiulli2 , S. Broggi2 , N. A. Iacovelli1 ,F. De Cobelli3 , C. Losio3 , R. Calandrino2 , N. G. Di Muzio1
1
I STITUTO S CIENTIFICO H.S. R AFFAELE, Department of Radiation
Oncology, Milano, Italy
2
I STITUTO S CIENTIFICO H.S. R AFFAELE, Department of Medical Physics
and Radiation Safety, Milano, Italy
3
I STITUTO S CIENTIFICO H.S. R AFFAELE, Department of Radiology, Milano,
Italy

Conclusions: D50, D95, D99 of PTV and CTV showed significant linear decrease as ROV increased. D95 of PTV decreased more than 2 Gy if ROV waslarger than 6.5 ml (=2/0.307). In eleven cases (about 20%) of our patients,
ROV were more than 6.5ml. In these cases we should do some to keep prescription doses as were intended. Increase a number of segments may be
one of solutions in those cases.

Rectal cancer
1048 poster
A CHOICE OF THE OPTIMAL STRATEGY OF ANAL CANCERINTRACAVITARY THERAPY
M. Chernykh1 , O. Kozlov1 , I. Gladilina1 , M. Nechushkin1 , A. Trigolosov1 , D.
Naumov1
1
N.N. B LOKHIN C ANCER R ESEARCH C ENTER, Brachytherapy andIntraoperative radiotherapy Unit, Moscow, Russian Federation
Purpose: To compare various methods of anal cancer treatment using different implants for different target configurations. We treated 27 patients forvarious tumors using 3 different applicators for the MicroSelectron.
Materials: 27 patients for various tumors using 3 different applicators for
the MicroSelectron:1. Simple proctostat with central channel. The applicator
can be completed with various shields: 90, 180 and 270 degrees.2. MUPIT
Applicator set.3. Miami Applicator Set.Patients have been treated using a
3D planning technique since 2007.3 groups of patients with different sizesof tumors were selected. Group 1: patients with minor thickness of tumors(0,5 cm). Treatment with the 1st applicator.Group 2: patients with moderate
thickness of tumors (0,5-1.2 cm). Treatment with the 2nd or the 3rd applicator.Group 3: patients with increased thickness of tumors (1-2+ cm). Treatment with the 1st and the 2nd applicator or with Miami with activation of thecentral channel.Distant radiation therapy for the minor pelvis was performed,
up to total irradiation dose of 44 Gy. After a gap, intracavitary radiation therapy was initiated. The irradiation was performed thrice a week, 3 Gy per
fraction. 6-8 fractions were performed. Total radiation dose=24-34Gy. The
PLATO brachytherapy planning system was used for dose and DVH calculations. Geometrical optimization was used for 1-3 applicators.Comparison
was performed with the following parameters: Coverage index (CI), External
volume index (EI), Relative Dose Homogeneity index (HI), Overdose volume
index (OI).Dose calculation algorithm in PLATO is based on the recommendation of the American Associaciation of Psysicists in Medicine (AAPM) Task
Group 43. Geometrical optimization was used for 1-3 applicators. Also wedetermined the dose at 12 reference points - six of them were at 2 mm fromthe applicator and defined maximum observed dose in the rectum, and theother six were at a distance of 5 mm from the tumor and these defined thedose decrease over the tumor.
Results: All patients tolerated the treatment well. 1-2 stage rectitis werenoted in all patients with the recovery in 2- weeks. The complete tumor
regress was observed in all patients. A local recurrent disease was foundin 3 patients in 6-12 months. Liver metastases were found in 1 patient in
13 months after the treatment.The reference points have clinical significance,

Purpose: To test the clinical feasibility of adaptive RT concomitant to oxaliplatin (oxa) and 5FU c.i. in rectal cancer.
Materials: With the aim of exploring a concomitant boost (SIB) approach on
the residual tumour during Tomotherapy, daily Megavoltage images (MVCT)of six patients previously treated within a moderate hypofractionated schedule
were used to assess rectal volume variations in the cranial (mobile) half ofthe rectum. Based on the results of this investigation, ten patients (pts) weretreated with a dose of 41,4 Gy in 18 fractions (2.3 Gy/fr) on PTV1 derived
from CTV (mesorectum and regional lymph-nodes) concomitant to 3 cyclesof oxa (100mg/m2 ) and 5-FU (250mg/m2 /day c.i.) while a daily dose of 2.7
Gy/fr (2 pts) and 2.9 Gy/fr (8 pts) was delivered during the last 6 fractions as
SIB on PTV2, corresponding to the residual tumour visible on an intermediate
MRI/CT with a margin taking rectal deformation into account.
Results: Most of the rectum volume variation was observed in the first halfof the treatment with an average reduction equal to 50%. A first estimateof optimized margins for adaptive radiotherapy with concomitant boost to thetumour was done by expanding the rectum at the first MVCT and at halftreatment MVCT with different margins (0.5, 0.7, 1, 1.5, 2 cm). Concerning
the second half of the treatment, more of the 90% (range: 82.4%-100%) of theunion was yet contained within a margin of 0.5 cm, while at least 1 cm marginis necessary to obtain the same coverage in the first part of the treatment. In
the 10 pts treated, PTV2 was defined as the residual tumour plus a marginof a 0.5 cm. NCI_CTC(v3) Intestinal acute toxicity was as follows: diarrhoea
G1-G2=50% , tenesmus G1-G2=40%. No G3 toxicity occurred. Five pts wereoperated. Initial stage was T4N+ (3 pts) and T3N1 (2 pts). Pathological stage
was pCR, pT3N0, pT4bN0, pT3N0, pT2N0 respectively.
Conclusions: The estimation of rectal volume variations gives the possibility to better guide the irradiation for preoperative treatment. In particular thetumour volume reduction and the possibility to decrease the PTV margin in
the second half of the treatment could allow an escalation of tumour doseusing SIB adaptive strategies with reduced margins for the T component of
the boost. No G3 intestinal acute toxicity occurred in the 10 pts treated. The
reduced motion of cranial rectum in the second half suggests also the possibility of adaptive concomitant boost during the last 6 fractions to the whole
PTV1 with avoidance of the rectum outside PTV2 and overlap between PTV1
and bowel/bladder.

S 391

1050 poster
CHANGES IN TUMOUR PERFUSION INDUCED BY NELFINAVIR
AND RADIOTHERAPY: TRANSLATION TO A PHASE I-II CLINICAL
TRIAL
E. Hill1 , N. Qayum1 , T. Brunner1 , P. Quirke2 , W. Mckenna1 , R. A. Sharma1
1
T HE G RAY I NSTITUTE OF R ADIATION O NCOLOGY AND B IOLOGY, Oxford,
United Kingdom
2
S T. J AMES U NIVERSITY H OSPITAL, Leeds - West Yorkshire, United
Kingdom
Purpose: The aim of this study was to translate the measurement of changes
observed in tumour vasculature during treatment with nelfinavir, an inhibitorof the PI3-kinase tumour cell signalling pathway and radiosensitising agent,from preclinical models to a clinical trial in patients receiving radiotherapy
for rectal cancer. It incorporated a novel histological technique, Tumour Cell
Density (TCD) analysis, as a primary endpoint for assessing the efficacy ofradiotherapy with a radiosensitising agent.
Materials: The pre-clinical aspect of this research involved the implantationof immunodeficient mice with human tumour xenografts. When the tumours
reached 100 mm3 , the animals were treated with nelfinavir at a dose of 20
mg/kg daily for 2 weeks. Three-dimensional power-doppler ultrasound was
performed to measure tumour blood flow when the tumours reached 100
mm3 and 14 days after treatment with nelfinavir both in the xenograft miceand in controls. The findings from this preclinical model were used to designa phase I-IIclinical trial in 80 patients with rectal cancer who received shortcourse radiotherapy (25 Gy in 5 fractions in 7 days) +/- nelfinavir 1250 mg bd
for 7 days before and then during radiotherapy. Patients recruited to this trial
underwent both diffusion contrast-enhanced (DCE)-CT and DCE-MRI scansof the pelvis pre-treatment, after 7 days of nelfinavir treatment alone and on
the last day of nelfinavir plus radiotherapy. Tumour perfusion characteristics measured by perfusion CT and DCE-MRI were compared with data frompreclinical models and changes in perfusion were correlated with morphological responses on conventional cross-sectional imaging 8 weeks post treatment to determine whether changes in perfusion predicted response to treatment. Pre-treatment biopsies and post-treatment biopsies taken 7 days after
completion of radiotherapy and nelfinavir were processed in order to analysechanges in TCD.
Results: In the preclinical model, nelfinavir treatment resulted in sustained
improvement in tumour blood flow, perfusion and oxygenation, as demonstrated by 3-D power-doppler ultrasound. Quantification of Doppler signal:volume ratio showed an increase after treatment with nelfinavir in tumours
after 14 days (p=0.046). Based on the optimal timescales demonstrated inthis model for radiosensitisation of tumours, the phase II clinical trial of radiotherapy and nelfinavir for locally advanced rectal cancer has opened torecruitment. The results of the phase I component of this trial, including assessment of TCD and vascular responses to nelfinavir and radiotherapy will
be presented at the meeting.
Conclusions: Based on the preclinical demonstration of a functional mechanism by which nelfinavir can cause radiosensitisation, a phase I-II clinical
trial of nelfinavir plus radiotherapy for rectal cancer has been designed andopened to recruitment. The phase I component of this trial has demonstrated
the feasibility of measuring both a novel histological biomarker and changes
in tumour perfusion
1051 poster
CLINICAL OUTCOMES IN ANAL CANCER: A SINGLE INSTITUTION
EXPERIENCE
S. Ahmad1 , R. Soomal1
1
S UFFOLK O NCOLOGY C ENTRE T HE I PSWICH H OSPITAL NHS T, Department of Clinical Oncology, Ipswich Suffolk, United Kingdom
Purpose: The management of anal cancer has evolved significantly in recent decades. Results from the ACT II trial confirm excellent response inanal SCC, complete response (CR) of 95%. Chemoradiotherapy (CRT) with
5-fluorouracil (5-FU) and mitomycin-C (MMC) is currently standard of careas first-line radical treatment. Anal adenocarcinoma is rarer with a lessfavourable outcome. AP resection remains an essential part of its treatment.
We report results in all anal cancer patients managed at our institution in thelast five years.
Materials: All anal cancer patients treated at The Ipswich Hospital NHS Trustfrom 2005-2010 were identified using local histology records and the Eastern
Cancer Registryand Information Centre (ECRIC).
Results: In total 27 patients were identified. 23 (85%) had SCC of which
2 presented with metastases. 2 of the 4 adenocarcinoma cases weremetastatic and treated palliatively. Median age 59 years (38-87); 19% male,
81% female. SCC stage T1-T2 (39%), T3-T4 (61%); node negative (52%),
positive (48%). Median follow-up was 28 months. In the SCC group, 1 patientwith T1 disease had excision biopsy alone and relapse free at 32 months
follow-up. The other 22 SCC patients, including 2 metastatic, were treatedradically with CRT, (5FU + MMC 95% or 5FU + cisplatin 5%). RT was administered in 2 phases as per ACT II 30.6 Gy + 19.8 Gy in 28 fractions of 1.8 Gy.
In 4 cases, phase 2 was given with IMRT and these patients had less acuteS 392R ECTAL CANCERR ECTAL CANCER

and a reduced area of grade 3/4 skin toxicity. 1 patient received an electron
boost and has severe chronic skin telangectasia. Grade 3/4 haematological
toxicity occurred in 17%. CR was 95%. In the adenocarcinoma group, the2 radical patients had N2 disease and received 45 Gy in 25 fractions to thepelvis with a 15 Gy in 7 fraction electron boost to groin nodes. Both achieved
clinical CR prior to AP resection and had a pathological CR as well. In allgroups only 3 patients required admission for acute treatment related complications. 3 SCC patients have relapsed (local only, local plus liver and liveronly) with 2 deaths from anal cancer and 1 from myocardial infarction. Bothmetastatic patients are alive with metastases but have controlled pelvic disease at 21 and 15 months follow-up. Recurrence free survival (RFS) at 2
years was 81% (13/16).
Conclusions: Our outcomes for anal SCC are similar to those in ACT II.
Complication rates were relatively low and patients receiving phase 2 IMRT
were noted to have reduced acute skin toxicity. Our data supports evidence
that anal cancer has an excellent response to CRT, CR 95% and RFS at
2 years 81% in SCC. IMRT was considered for Phase 2 in complex volumes
and appears a potential option to reduce acute/late toxicity and avoid electron
boosts. Most patients were treated radically and benefit from local disease
control even when metastases are present.

1052 poster

1053 poster

DOSE DISTRIBUTION OF CONFORMAL RADIOTHERAPY USINGFIELD-IN-FIELD TECHNIQUE IN RECTAL CANCER
M. J. Chung1 , J. H. Lee1 , J. Y. Kim1 , G. W. Lee1 , I. G. Lee2 , S. M. Chung1

EFFECTS OF CARBON ION BEAM ON PUTATIVE COLON CANCERSTEM CELLS AND ITS CORRELATION WITH RADIOCURABILITY
S. Sai1 , K. Oonishi2 , S. Yamada2 , T. Kamada2 , R. Okayasu1
1
N ATIONAL I NSTITUTE OF R ADIOLOGICAL S CIENCES (NIRS), Radiation
Biology, Chiba, Japan
2
N ATIONAL I NSTITUTE OF R ADIOLOGICAL S CIENCES (NIRS), Departmentof Clinical Oncology and Radiotherapy, Chiba, Japan

1C OLLEGE OF M EDICINE , T HE C ATHOLIC U NIVERSITY OF KOREA,
Department of Radiation Oncology, Seoul, Korea Republic of
C OLLEGE OF M EDICINE , T HE C ATHOLIC U NIVERSITY OF KOREA,
Department of General Surgery, Seoul, Korea Republic of2

Purpose: The traditional standard four-field technique in rectal cancer toirradiate gross tumor and regional lymphatics often fails to cover the centrally positioned rectal cancer with prescribed dose without hot spots in thesmall bowel. We carried out a comparative treatment planning study to determine whether the three-dimensional conformal radiotherapy with a field-in
field technique improves target dose distribution and normal tissue avoidance
for rectal cancer.
Materials: Thirty consecutive rectal cancer patients were included. Twenty
two patients were preoperative aim and eight patients were salvage aim forrecurrence in anastomosis site. Gross target volume (GTV), rectum, bladder, small bowel, femur head were outlined on the radiation therapy planningcomputed tomography with prone position. Clinical target volume to include
mesorectum and pelvic nodal chain and planning target volume to accountfor patient set up errors were created on radiation treatment planning system. We made two plans standard four field radiation technique (4FRT) andfield-in-field technique (FIFT) for each patient to ensure coverage of the PTV
with the 95% isodose line and to limit the small bowel not exceeding 107% of
the prescription dose. The field border of standard four fields included PTV
by the guidance of bony landmarks on digitally reconstructed radiographs. In
FIFT, the weight of original set of fields is reduced and the second set of fields
with reduced field size was designed in the same angle to avoid the 103% of
the prescribed dose in 4FRT. The prescribed dose is 180 cGy/fraction. Dosevolume histogram of the GTV, CTV, PTV and small bowel was compared between two techniques.
Results: Mean dose of GTV, CTV, PTV were significantly higher in FIFT
(182.9 cGy, 181.2 cGy, 181.3 cGy) than 4FRT (180.8 cGy, 180.1 cGy, 180.4
cGy) (p < 0.001, p = 0.001 and p = 0.002, respectively).The volume receiving more than 100% of prescribed dose (V100) of GTV, CTV, PTV were significantly increased from 70.1%, 73.2%, 74.4% in 4FRT to 90.8%, 84.3%,
83.8% in FIFT (p < 0.001, p < 0.001 and p = 0.001, respectively). On theother hand, FIFT significantly reduced the V95 of small bowel (4FRT=22.4%,
FIFT=21.7%; p=0.005)and Dmax of small bowel (4FRT= 189.9 cGy, FIFT=
188.8 cGy; p=0.011). In FIFT, we used median 2 additional in field portals (range, 1-4), median field size 6.5x13.2cm in field portals (range, 4x412x18cm). Median monitor unit of additional in field portals was 5 (range,2-14).

Purpose: To investigate whether carbon ion irradiation had beneficial effects
by targeting putative human colon cancer stem cells
Materials: Colony formation assay, spheroid formation assay, FACS analysis,
as well as xenograft tumor growth control analyses were performed by carbon
ion and X-ray irradiation (IR) in human colorectal cancer cells HCT116 andSW480.
Results: The relative biological effectiveness value of carbon ions relative
to X-rays was calculated to be 1.6 in vitro (D10 survival fraction) and 3.9 invivo (tumor regrowth delay). CD133+, CD44+/ESA+ cells significantly havehigher number of colony, spheroid and less of gammaH2AX foci compaered
to CD133-, CD44-/ESA-cells. CD133+, CD44+/ESA+ cells were showed radioresistance to both X-ray and carbon ion IR, but carbon ion IR has more
effect to kill CSC. CD133+, CD44+/ESA+ cells have shown more potential toform tumors in SCID mice than CD133-, CD44-/ESA-cells, and carbon ion IR
has more effectively eradicate xenograft tumors compared to X-rays.
Conclusions: Heavy ion irradiation has a great potential to effectively target
radioresistant putative cancer stem cells. This is considered to be one of
the major contributing factors for the high radiocurability of heavy ion cancer
treatment.
1054 poster
ESTIMATION OF CTV TO PTV MARGINS FOR PREOPERATIVERECTAL CANCER RADIOTHERAPY
J. Park1
1
INHA U NIVERSITY , Radiation Oncology, Daejeon, Korea Republic ofPurpose: To determine the magnitude of setup and organ motion errors froma subset of rectal cancer patients treated with preoperative radiotherapy, andto estimate the CTV-PTV margin according to published margin recipes.
Materials: A prone position planning CT and every other day pre-treatment
electronic portal images were acquired for 10 patients. Cone beam CT scans
were acquired after treatment. Using automatic registration, the necessary
setup margin was investigated by means of bony landmarks. Using the planning CT scan as a reference, volumetric and positional changes were analyzed in the subsequent CT scans.
Results: Based on pre-treatment OBIs, the required setup margins computed with published margin recipes were 0.93 cm, 0.94 cm, and 1.24 cm inthe lateral, vertical, and longitudinal directions. Using post-treatment CBCT,
the required setup margins were 0.52cm, 0.36cm, and 0.43 cm in the lateral, vertical, and longitudinal directions. Motion of the CTV was not equalin all directions. Clinical margin should be differentiated in position along the
cranio-caudal axis, in the anterior-posterior direction. The largest differencein the CTV occurred 10 cm caudal to the anus, with a standard deviation of
6 mm. The current clinical uniform PTV margin of 1cm appears to be insufficient.
Conclusions: Customized PTV margin definition has been possible throughin-house measurements of geometrical clinical uncertainties involved in theconformal radiotherapy process. Additional margin reduction procedures areneeded in order to accomplish conformal radiotherapy goals.
1055 poster

Conclusions: A significant dosimetric advantage of FIFT over standard
4FRT in whole pelvic irradiation for rectal cancer was shown in terms of target
covering and small bowel sparing. Conformal radiotherapy using FIFT could
be an alternative choice for novel technique like IMRT..

HIGH-DOSE NEOADJUVANT RADIOCHEMOTHERAPY FOLLOWEDBY SURGERY IN MRI AND EUS-DEFINED POOR-RISK RECTALCANCER.
P. Calvo Crespo1 , R. GARCÍA FIGUEIRAS2 , E. Fernández Fernández3 ,J. PAREDES COTORE4 , B. TABOADA VALLADARES3 , J. IGLESIAS5 , A.
Carballo3 , P. Peleteiro3 , V. Luna Vega6 , A. Gomez Caamaño3
1
H OSPITAL C LÍNICO U NIVERSITARIO, Radiation Therapy Department,
Santiago de Compostela, Spain
2
H OSPITAL C LINICO DE S ANTIAGO, Radiology Department, Santiago deCompostela, Spain
3
H OSPITAL C LINICO DE S ANTIAGO, Radiation Therapy Department,
Santiago de Compostela, Spain
4
H OSPITAL C LÍNICO U NIVERSITARIO, Surgery Departement, Santiago deCompostela, Spain
5
H OSPITAL C LÍNICO U NIVERSITARIO, Gastroenterology, Santiago deCompostela, Spain
6
C OMPLEJO H OSPITALARIO U NIVERSITARIO DE S ANTIAGO DE C OM POSTELA (CHUS), Radiotherapy Physics, Santiago de Compostela, Spain

S 393

Purpose: To evaluate high-dose Neoadjuvant Radiochemotherapy followed
by Surgery in MRI and EUS-Defined Poor-Risk Rectal Cancer.
Materials: The criteria for poor-Risk rectal cancer were tumours with circumferencial resection margin threatened, T4 tumors, and N2 tumors. Patients
received high dose neoadyuvant radiotherapy with a median dose of 59.4
Gy with a concomitant fluoropyrimidine based chemotherapy. Surgery wasplanned 6-8 weeks after CRT. The pathologic responses and toxicity were
evaluated as study endpoints.
Results: Between January 2006 and November 2009, 41 elegible patientswere recruited. Thirty-seven patients underwent surgery. The complete
pathologic response rate was 17.9%. Twenty patients had down-staging(54.1%). T down-staging was achieved in 23 patients (65.7%). During preoperative radiochemotherapy no patients had Grade 3-4 toxicity. Diarrhea andproctitis was the most common type of toxicity. Thirteen patients (31.7%) developed surgical wound infection, one patient had anastomotic leak (2.4%),
one patient had urinary fistula (2,4%) and three patients had presacral abscess. There was no perioperative mortality. At a median follow up of 21months, only one local recurrence was detected (2.4%) and sixteen patients
had systemic recurrence (39%).
Conclusions: High-dose Neoadyuvant Radiochemotherapy was found to beeffective in poor- risk rectal cancer, with higher responses rates, dowstaging
and with manageable toxicities.
1056 poster
IMPACT OF NEOADJUVANT CHEMORADIATION IN LOCALLYADVANCED CARCINOMA RECTUM- A FEASIBILITY STUDY IN
INDIA.
M. K. B.12
1
AIIMS, Radiation Oncology, New Delhi, India
2
P OST G RADUATE I NSTITUTE OF M EDICAL E DUCATION AND R ESEARCH,
Radiation Oncology, Chandigarh, India
Purpose: To evaluate the rate of sphincter preservation, tumor downstaging,
local control and acute toxicities of Neoadjuvant chemoradiation in locally advanced distal rectal carcinoma.
Materials: A total of 64 patients have been enrolled in this single arm feasibility study from July 2007 to December 2009. All the patients were initially evaluated and declared as locally advanced carcinoma rectum requiring abdominoperineal resection by gastrointestinal (GI) surgeon. Patientswith clinical T3 / T4 and N1/N2 cancer of distal rectum were subjected toreceive Combined Neoadjuvant chemoradiation followed by surgical resection. All the patients were given inj. Leucovorin (@30 mg/m2 ) and inj. 5FU (@325 mg/m2 ) D1 concurrently with radiation of 45 Gy/25# @ 1.8 Gy
for 5 weeks. Megavoltage external beam (6 MV-15 MV) delivered with four
field Box technique. All the patients were immobilized in prone position on
a ’BELLY BOARD’. Multi Leaf Collimators were used to spare posterior soft
tissue and small bowel.Surgery was performed 4-6 weeks after completionof chemoradiation by the same GI surgeon. The primary end points of thisstudy were tumor regression and sphincter preservation. Acute normal tissue
toxicities were taken into account as secondary point.
Results: The study showed overall resectability rate of 81% and a sphincter
preservation rate of 55%.The complete pathological response rate was 39%.
Only 19% patients were declared inoperable in whom palliative colostomy
were done. The main complication observed were Non hematological toxicities: diarrhoea grade III = 21% and skin reaction grade II =16%; grade III=5%). Grade II neutropenia (5%) and grade I thrombocytopenia (2%) were thehematological toxicity observed. With a median follow up period of 14 months
no loco-regional failure has been seen. Only one patient has failed distantly
presenting with lung metastasis without any local failure.
Conclusions: Concurrent preoperative chemoradiation for locally advanced
carcinoma rectum is associated with improved tumor resectability which results in improved sphincter preservation, local control and is relatively safe,
effective and well tolerated.
1057 poster
LATE FUNCTIONAL OUTCOME AND QUALITY OF LIFE AFTER
RADIOTHERAPY AND SURGERY FOR RECTAL CANCER
M. Guren1 , K. Bruheim1 , B. L. Rekstad2 , K. M. Tveit1
1
O SLO U NIVERSITY H OSPITAL, Medical Oncology and Radiotherapy, Oslo,
Norway2
O SLO U NIVERSITY H OSPITAL, Medical Physics, Oslo, Norway
Purpose: An increasing number of patients receive radiotherapy or chemoradiotherapy for rectal cancer. The rate of local recurrence has decreased, andsurvival increased. The objectives have been to investigate the late side effects and functional outcome in irradiated rectal cancer survivors, the relation
to normal tissue radiation dose, and measures to prevent late effects.
Materials: All patients diagnosed with rectal cancer are registered in a national database. Recurrence-free patients diagnosed in 1993-2003 were invited to participate in a follow-up study; 199 irradiated and 336 surgery-only
patients were included. Functional outcome of bowel, anorectal, urinary, andS 394R ECTAL CANCERR ECTAL CANCER

sexual function, male hormonal status, and health-related quality of life was
examined, and have been published. Studies are ongoing to correlate normal
tissue radiation dose with functional outcome, and to investigate techniques
for reducing normal tissue dose.
Results: In an early study we found that type of surgery had only minimal
influence on quality of life; however, irradiated patients had worse rectal function in terms of frequency, urgency, and incontinence (p<0.01). The follow-up
study assessed functional outcome after median 4.8 years. Irradiated patients were more often incontinent for liquid stools (49% vs 15%, p<0.001),
needed sanitary pad (52% vs 13%, p<0.001), and lacked ability to defer defecation (44% vs 16%, p<0.001). Patients with faecal or urinary incontinence
had impaired score for social function and global quality of life (p<0.001). Irradiated patients had increased odds ratio for erectile dysfunction (p<0.001)
and had more vaginal problems than surgery-only patients. Mean serum
testosterone was reduced in irradiated patients (p<0.001), related to low fieldedge. These findings of late effects in a national patient sample are in accordance with findings from prospective trials.Further studies are ongoing toinvestigate the relationship between normal tissue dose and later functional
outcome. A dose-planning study found that half beam technique may reduce mean testicular dose while maintaining the dose to the target volume.
Systematic counseling/treatment of patients with poor anorectal function isplanned.
Conclusions: Long-term survivors after radiotherapy for rectal cancer are at
risk for poor functional outcome that may have an impact on the quality of life.
Increased knowledge may lead to better prevention and treatment of late side
effects.

Chemotherapy consisted of orally administered capecitabine in most patients.
Results: With the exception of 9 patients who presented in poor general condition, we treated the rest with radical intent. However, treatment toxicities
were quite significant in both groups (post-op and pre-op radiochemotherapy groups). In particular, hematological and gastrenteric grade II-III toxicity
occurred in almost 80% in those treated with postoperative radiochemotherapy and resulted in modifications or treatment discontinuation in 15 out of 19(78%). Those treated with preoperative combined therapy had better tolerance; grade II-III toxicities experienced by 52% of patients while 85% managed to complete therapy with no significant modifications. Clinical and radiological response was seen in all, however, only 14 of 20 underwent surgery,
4 were poor candidates for open operation and 2 refused surgery. Of thosepatients treated palliatively, 5 managed to receive a worthwhile dose (30Gy)
and had a significant improvement of their symptoms although side effects
were not negligible while 4 received only a few fractions of radiotherapy andhad no symptom response.
Conclusions: Older patients with rectal cancer can be treated radically provided that their general condition is satisfactory. They should be managedwith preoperative chemoradiotherapy instead of postoperative while particular care should be given to the technical aspects of radiotherapy as well as
the chemotherapy schedules in order to minimize toxicity.
1060 poster
MOLECULAR AND BIOLOGICAL BASIS OF THE ASSOCIATION OF
RADIOTHERAPY, 5-FLUOROURACIL AND GEFITINIB IN RECTALCANCER
I. Palumbo1 , S. Piattoni2 , F. Falzetti2 , P. Contavalli2 , V. Marini2 , M.
Lupattelli3 , M. A. Gambacorta4 , F. M. Vecchio5 , S. Dazzini3 , C. Aristei1
1
R ADIOTERAPIA, Dipartimento di Scienze Chirurgiche, Radiologiche eOdonstomatologiche, Università di Perugia, Perugia, Italy
2
E MATOLOGIA ED I MMUNOLOGIA, Dipartimento di medicina Clinica e
Sperimentale, Università di Perugia , Perugia, Italy
3
R ADIOTERAPIA, Azienda Ospedaliera di Perugia , Perugia, Italy
4
S EZIONE DI R ADIOTERAPIA, Dipartimento di Bioimmagini e Scienze
Radiologiche, Università Cattolica del Sacro Cuore, Roma, Roma, Italy
5
A NATOMIA PATOLOGICA, Dipartimento di Patologia Umana, Università
Cattolica del Sacro Cuore, Roma, Roma, Italy

1058 poster
LOCAL EXCISION AND CONTACT RADIOTHERAPY (CXR) FOR
EARLY RECTAL CANCER: A SINGLE INSTITUTION EXPERIENCE
V. S. Ramani1 , A. Sun Myint1 , A. Montazeri1 , H. Wong2
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Clinical Oncology, Bebington,
Merseyside, United Kingdom
2
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Clinical Effectiveness ,Bebington, Merseyside, United Kingdom
Purpose: Surgery in the form of Total Mesorectal Excision (TME) remains
the gold standard treatment for early rectal cancer. TME is associated withconsiderable morbidity and mortality especially in the elderly and frail. Conservative alternatives include local excision techniques such as Trans-anal
Endoscopic Microsurgery (TEM) or Trans-anal Resection (TAR); endocavitary Contact Radiotherapy (CXR); laser photocoagulation etc. However in
the UK TEM alone has been found to have a high risk of local recurrencesof 18% and 29% for pT1 and pT2 tumours respectively.The purpose is topresent outcome data for patients treated with local excision followed by CXR
in our centre
Materials: Data was collected retrospectively from patient case notes. Descriptive statistics were used to analyse the data using SPSS v18.
Results: Between 1993 and 2007, 45 patients with early rectal cancer (pT1,
pT2 N0) were treated with local excision followed by CXR. All patients werestaged by clinical examination and radiology (CT, MRI or trans-anal ultrasound). CXR was delivered to the local excision scar via a rectal applicator using a therapax machine (energy 50KV). Details of patient characteristics, tumour stage, treatment and recurrence details are as shown in thetable.Majority (56%) patients underwent a TAR as the local excision procedure. Median total CXR dose was 60Gy in 2 fractions with a range of 20-110
Gy. A significant proportion (82%) had adjunct external beam radiotherapy(EBRT) before or after CXR (78% long course and 4% short course radiotherapy).After a median follow up of 2.76 years (range 0.13-13.95 years) 3
patients had local recurrence (7%) at the site of previous treatment and 1(2%) had distant relapse. Two of the 3 local recurrences were salvaged successfully with surgery and remain NED at the time of last follow up. Disease
free survival after salvage surgery is 98%. No treatment related mortality wasobserved.

S 395

Conclusions: Local excision followed by endocavitary CXR with or without
EBRT is a reasonable option for patients with early rectal cancer who have ahigh risk of morbidity and mortality from TME surgery and in those wishing to
avoid a permanent stoma.
1059 poster
MANAGEMENT OF RECTAL CANCER IN THE ELDERLY
L. Vini1 , N. Gouvas2 , C. Kakana3 , A. Silyvridou4 , E. Diamantidou5 , D.
Hourmouzi6 , E. Xynos2
1
ATHENS M EDICAL C ENTRE, Radiation Oncology , Athens, Greece
2
AG S OFIA H OSPITAL, Surgery, Athens, Greece
3
I NTERBALKAN M EDICAL C ENTER, Medical Physics, Thessaloniki, Greece
4
ATHENS M EDICAL C ENTRE, Medical Physics, Athens, Greece
5
I NTERBALKAN M EDICAL C ENTER, Medical Oncology, Thessaloniki, Greece
6
I NTERBALKAN M EDICAL C ENTER, Radiology, Thessaloniki, Greece
Purpose: To assess tolerance and toxicities as well as results of multimodality treatment in elderly patients with rectal cancer.
Materials: Between 2002 and 2009, 61 patients with rectal cancer aged at diagnosis over 70 years (range 70-84 years) were treated in our center. There
were 39 male and 22 females with biopsy proven adenocarcinoma of therectum and localized disease in the pelvis (19 had stage II and 29 stage
III disease). ECOG performance status was 0/1 in 35 patients and 2/3 in
13. Nineteen patients were initially treated surgically (7 underwent an AP resection) and were then given postoperative radiotherapy and chemotherapy.
Twenty patients were primarily treated with chemoradiotherapy followed bysurgery in 14 while the remaining 9, were treated with palliative radiotherapy for symptom control because of their poor general condition. Radiotherapy was 3D conformally planned and delivered with a 3-field technique on
18MV linear accelerator. Postoperatively the median administered dose was
40Gy (28-52.2Gy) and preoperatively 45Gy (36-50.4Gy) in 1.8Gy per fraction.

Purpose: To evaluate the molecular and biological basis of integrated treatment with radiotherapy (RT), 5-Fluorouracil (5-FU) and gefitinib in a colorectal
cell line (LoVo) with moderate EGFR expression (representative of the general population of patients affected by rectal cancer).
Materials: Cells were treated with fractionated RT (2 Gy every day for 3 consecutive days up to 6 Gy), 5-FU (0.3, 2.5, 5 mM), gefitinib (0.2,0.4,0.8 mM),
RT+5-FU, RT+ gefitinib, 5-FU+ gefitinib and RT+5-FU+ gefitinib. EGFR expression was determined by western blotting (WB) and reverse transcription
real-time PCR. Viable cells were evaluated. The cell cycle was investigatedusing cytofluorimetry with iodurum propide (IP) and WB for cyclines A, B and
E. DNA damage was assessed by WB for p53, p21 γ H2AX and reverse transcription real time PCR for ERCC1. EGFR signalling pathways was assessed
by WB for EGFR, P-EGFR, AKT, P-AKT, ERK1-2, P-ERK1-2 and apoptosis bycytofluorimetry with IP and by WB for caspases 8 and 9. Clonogenic capacity
was determined by colony forming unit assay.
Results: Here we report only results on RT, 5-FU (0.3 mM) and gefitinib (0.4mM) alone and combined (5-FU+gefitinib 48h before RT and during RT), as
evaluated 48 hours after RT. RT reduced cellular proliferation by about 70%,
induced cell cycle arrest in G1 and G2-M and DNA damage, activated EGFR
signalling pathways (in particular P-EGFR and P-AKT), induced apotosis andreduced clonogenic capacity by about 68%. 5-FU reduced cellular proliferation by about 80%, induced cell cycle arrest in S and high level DNA damage,activated EGFR, induced apotosis and reduced clonogenic capacity by about
50%. Colonies were larger than in control cells due to aggressive behaviourof 5-FU surviving cells. Gefitinib reduced cellular proliferation by about 50%,
induced cell cycle arrest in G1 and G2-M, did not induce DNA damage, inactivated EGFR, induced apotosis and reduced clonogenic capacity by about di40%. RT+5-FU+gefitinib had a synergistic effect. The most interesting characteristic was the clonogenic capacity. In fact not only the number but also
the size of colonies were reduced (figure 1).

Conclusions: Our results confirm that RT caused DNA damage and increased P-EGFR, as reported elsewhere, especially at low doses. 5-FU hada cytotoxic effect and interfered with DNA syntesis. Gefitinib had a cytostatic
effect.5-FU induced more marked DSB and cell-death than RT, but surviving
cells were activated towards proliferation (P-EGFR, P-AKT and P-ERK1-2
upregulation). 5-FU+RT acted synergistically, but activation of surviving cells
persisted. Gefitinib seemed to interferes with increased proliferation of surviving cells after 5-FU. Colonies of cells treated with RT+5-FU+gefitinib were
smaller and fewer than those formed by cells treated only with RT+5-FU.
1061 poster
MULTIDISCIPLINARY MANAGEMENT OF LOCALLY RECURRENT
COLORECTAL CANCER
N. Gouvas1 , L. Vini2 , A. Silyvridou3 , E. Diamantidou4 , C. Dervenis1 , E.
Xynos1
1
AG S OFIA H OSPITAL, Surgery, Athens, Greece
2
ATHENS M EDICAL C ENTRE, Radiation Oncology, Athens, Greece
3
ATHENS M EDICAL C ENTRE, Medical Physics, Athens, Greece
4
I NTERBALKAN M EDICAL C ENTER, Medical Oncology, Thessaloniki, Greece
Purpose: This is a retrospective study aiming to assess the effectiveness ofmultimodality treatment, chemotherapy, radiotherapy and surgical resectionin the management of locally recurrent colorectal cancer.
Materials: Between 2002 and 2007, 21 patients with recurrent colorectal cancer were referred to our center. There were 14 male and 7 female patientswith a median age of 58 years (range 32-82 years). Sixteen patients had
rectal carcinoma treated with surgery 16-42 months earlier; 2 of these hadreceived adjuvant radiotherapy and 5 chemotherapy. Five patients had ceacal cancer treated with surgical resection and chemotherapy 20-38 months
earlier. The recurrence was documented with CT scan in 6, MRI in 11 andPET-CT scan in 4. In addition to local recurrence, 3 patients also had metastases in the liver. Three patients were initially treated surgically and werethen given radiotherapy and chemotherapy while the remaining 18 were initially treated with concurrent chemo-radiotherapy and surgery was performed
later in 12. Radiotherapy was CT simulated and 3D conformally plannedand delivered with 18MV linear accelerator to a median dose of 48Gy (range
38Gy60Gy). Chemotherapy consisted of continuous infusion of 5FU in 5 and
Xeloda in 16 (9 were also given oxaliplatin).
Results: The 3 patients who initially underwent surgery, had localised small
volume recurrence at the anastomosis; two remain disease-free 21 and 38
months after treatment and the third is alive with recurrence in the liver 19months after the local recurrence. Of the 18 patients who were treated withchemoradiotherapy, response was documented radiologically in 15 (83%).
Two patients with PET-CT confirmed complete response had no further treatment and remain disease-free for 6 and 10 months. Fourteen patients underwent surgical resection of the residual disease and their median survival was
21 months, 3 refused surgery and 2 (with no response to chemoradiation)
were deemed inoperable. All 5 developed progressive disease locally (3 also
developed liver, bone and brain metastases) and their median survival was
13 months.
Conclusions: The management of locally recurrent colorectal cancer is difficult. This small retrospective series indicates that a combination of chemoradiotherapy and surgery offers the best results in terms of local control andprobably survival.

S 396R ECTAL CANCERR ECTAL CANCER

1062 poster
NEOADJUVANT CHEMORADIATION IN LOCALLY ADVANCEDRECTAL CANCER
P. Meireles1 , D. Fonte1 , A. Costa2 , D. Almeida2 , M. Reis Lima Marques1 , C.
Sarmento2 , C. Rey2 , G. Pinto1
1
H OSPITAL DE S ÃO J OÃO, Department of Radiation Oncology, Porto,
Portugal
2
H OSPITAL DE S ÃO J OÃO, Department of Medical Oncology, Porto, Portugal
Purpose: Neoadjuvant combined therapy has become the standard of carein Locally Advanced Rectal Cancer. This approach has demonstrated improved local control rates, pathological complete response and downstage of
locally advanced disease preoperatively. The endpoints of this study were
downstaging and pathological complete response.
Materials: We retrospectively evaluated 140 patients that received neoadjuvant chemoradiation for locally advanced rectal cancer between January
2003 and June 2010. Ten cases were excluded from this analysis due tothe lack of information regarding the chemotherapy regimen used. RT dose
ranged from 45 Gy in 25 fractions to 50,4 in 28 fractions. The most recent
patients received 50 Gy in 25 fractions. Concurrent chemotherapy was either
5-FU based or with capecitabine. Surgery was performed 6-8 weeks after theend of neoadjuvancy.
Results: The median age at diagnosis was 63 years with a minimum of 34
and a maximum of 83 years. There was a male predominance (63,1%) in the
study population. Regarding location 9,2% of the cases where in the upper
third of the rectum, 38,5% in the middle third and 52,3% in the lower third.
According to clinical staging, 33,8% of the cases were in stage IIa, 4,6% instage IIb, 60,8% in stage IIIb and 0,8% in stage IIIc. All patients received
chemoradiation. The chemotherapy regimen was 5-FU based in 60,8% of
the patients and capecitabine in 39,6%. The radiotherapy fractionation waseither 1,8 or 2 Gy/daily fraction, with a total dose that ranged from 45 Gy
to 50,4 Gy for the patients with a 1,8 Gy/daily fraction and 46 to 50 Gy forpatients with a 2 Gy/daily fraction. One patient had to stop treatment with a
total dose of 36 Gy due to hematologic toxicity. Surgery was performed in
129 patients and 1 patient refused. Of those 129 patients 41,1% had an abdominoperineal ressection, 52,7% a low anterior ressection and in 6,2% was
nonresectable. There was downstaging after neoadjuvante chemoradiationin 61,2% of cases. In 13,2% (17 patients) there was a pathological complete
response (pCR) after neoadjuvant chemoradiation.
Conclusions: Neoadjuvant chemoradiation with 5-FU or capecitabine allows
pCR and downstaging. These results are similar to those published in theliterature
1063 poster
NEOADJUVANT VOLUMETRIC MODULATED ARC THERAPY FOR
RECTAL CANCER: ANALYSIS OF ACUTE TOXICITY DATA OF 16
PATIENTS
A. Cecconi1 , P. Porcu2 , M. C. Leonardi1 , R. Lazzari1 , B. A. JereczekFossa1 3 , A. Vavassori1 , R. Mauro1 3 , E. Rondi4 , S. Vigorito4 , F. Cattani4 , C.
Fodor1 , R. Orecchia1 3
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Radiotherapy, Milan,
Italy
2
F ONDAZIONE S ALVATORE M AUGERI, Division of Radiotherapy, Pavia, Italy
3
U NIVERSITY OF M ILAN, Milan, Italy
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Medical Physics, Milan,
Italy
Purpose: Pre-operative chemo-radiotherapy (CT-RT) of rectal cancer (RC)in locally advance stage has become a widely accepted treatment modality.
Aim of the present study is to evaluate feasibility and acute toxicity in a seriesof 16 patients (pts) treated with neoadjuvant volumetric intensity modulated
arc therapy with RapidArc (RA-IMRT) for RC.
Materials: From February to October 2010 16 pts affected by locally advanced RC were treated with neoadjuvant RA-IMRT. 11 pts were male and 5
pts were female, median age was 63 years. The T stage distribution was asfollows: T2, T3 and T4 in 2 pts (12.5%) in 13 pts (81.5%) and in 1 pts (6.25%),
respectively. The N stage distribution was as followes: N0, N1 and N2 in 3
pts (18.7%), 9 pts (56.2%) and 4 (25%), respectively. 3 pts had proximal, 3
pts had medium-distal and 9 distal(RC).In all pts concomitant chemotherapy
with oral capecitabine schedule was added to RA-IMRT. All pts underwent a 3mm slicing simulation/treatment planning CT scan from diaphragm to lesser
trochanter.Clinical target volume (CTV) of the primary tumor was created byaddition of 10 mm to GTV. Margins of 5/10mm and 5 mm were added tocreate PTV-T (planning target volume) and PTV-N from CTV-T and CTV-N,
respectively.Dose prescription was set according to simultaneous integrated
boost (SIB) strategy to 55 Gy to the primary tumor and positive lymph nodes(N) (at 2.2Gy/fraction) and to 45 Gy (at 1.8 Gy/fraction) to N risk area including presacral, internal and external iliac and obturator N. Before treatment all
pts were seen by radiation oncologist. During RA-IMAT patients were visited
twice a week, and then at the end of treatment.The RTOG/EORTC criteria
were used to evaluate the acute genito-urinary (GU), the gastro-intestinal (GI)and the skin toxicity (SKT).

Results: Before treatment all pts had a Karnofsky performance status (KPS)
100 and 2 pts complained about pain, 9 pts bleeding, 4 pts constipation, 1 pt
abdominal distension, 2 pts diarrhea, and 4 pt had diarrhea or constipation
alternately. 15 out of 16 pts have now completed treatment without any interruption. 1 pt stopped treatment for "metabolic syndrome X" (36 Gy). Acutetoxicity at the end of RA-IMRT included GI (G0: 4 pts; G1: 5 pts, G2:6 pts);
GU (G0: 7 pts, G1: 4 pts; G2:4 pts); and SKT (G0:7 pts, G1: 7 pts, G2:1 pts).
Conclusions: Our preliminary experience showed that RA-IMAT is a highly
tolerable treatment modality with low GU, GI and SKT, as demonstrated by
the complete absence of toxicity G3 at the end of treatment despite dose escalation and SIB.Further investigation with higher patient number and longer
follow-up is warranted in order to verify if low acute toxicity observed in our
preliminary analysis is translated to low late toxicity and satisfactory tumour
control.
1064 poster
ON THE DEVELOPMENT AND CLINICAL IMPLEMENTATION OF
AN INCLINED BELLY BOARD FOR CONSISTENT SMALL BOWELDISPLACEMENT
V. Kundapur1 , G. Cranmer-Sargison2 , H. Vachhrajani1 , N. Sidhu2
1

S ASKATOON C ANCER C ENTRE, Radiation Oncology, Saskatoon,
Saskatchewan, Canada
S ASKATOON C ANCER C ENTRE, Department of Medical Physics andRadiation Safety, Saskatoon, Saskatchewan, Canada

2of p53 immunohistochemical staining of pretreatment biopsy specimens andpathohistological response to preoperative chemoradiotherapy.
Materials: Between October 2006 and December 2008, 50 patients with locally advanced rectal cancer (T3 stage -76%, T4 stage - 24%) were treatedwith preoperative radiotherapy with total dose of 45 Gy combined with concomitant chemotherapy Mitomycin C and Capecitabine. Surgery was performed six to eight weeks after the end of chemoradiation. p53 immumohistochemical staining was performed on pretreatment biopsy specimens in all
patients and results were compared with histopathological tumor regression
according to a standardized semiquantitative score grading system. p53 wasconsidered overexpressed when ≥10% of the malignant nuclei was positive.
If fewer than 10% of the nuclei were stained, the specimen was scored ashaving normal p53 expression.
Results: All patients underwent surgery. At pathologic examination, 8(16%)
of 50 patients had a pathologic complete response (pCR), 8 (16%) were pT2,
32 (64 %) pT3 and 2 (4%) pT4. Positive lymph nodes were detected in 22(44%) patients. Overall, 48% of patients had major tumor downstaging. Outof 50 pts, overexpression was noted in 33 pts (66%) and 17 pts (34%) had
normal exspression on biopsy specimen. After surgical resection pathological complete response (pCR) was noted in 2pts(11,76%) with normal p53
expression and in 6 pts(18,18%) with p53 overexpression, but we didnt findstatistical significant diference between tested groups (p=0.699).
Conclusions: We did not find correlation between p53 overexpression andhistopathological response to preoperative chemoradiotherapy. The same
result was obtained by majority of other published studies until now.
1066 poster

Purpose: Excluding small bowel (SB) during pelvic radiation is challenging.
Techniques and devices reported on in the literature are varied. To date, very
little data has been published on the true SB displacement during treatment
and no published work on the reproducibility in SB displacement. We havedeveloped an inclined belly board (iBB) that is ergonomic, ensures stable patient set up and provides reproducible small bowel displacement. We validate
the reproducibility in SB displacement during treatment using CBCT.
Materials: An initial 49 patients were treated on an iBB constructed in-house.
Patient set-up, comfort and small bowel displacement were all assessed andfrom our recommendations a commercial iBB produced by CDR System Inc.
A total of 69 patients have now been treated on the commercial iBB. Patient
treatment position, as well as the consistency in small bowel displacement,
has been quantitatively and qualitatively assessed for 24 of the 69 patientsusing CBCT data. At treatment, a set of kV-kV images were taken daily, abony anatomy match performed and subsequent couch moves made alongeach axis. CBCT data was acquired once every 5 fractions (weekly) for a
total of 5 images per patient. A 3D-3D bony anatomy auto-match was performed offline and the residual difference in position recoded for analysis. A
Likert response scale questionnaire was used to assess the quality in small
bowel displacement (CT data) and the consistency of the displacement overthe course of treatment (CBCT data). The evaluations were conducted on
12 of the 24 patients by 2 ROs blinded for patient information. A quality assurance (QA) program has been developed for the routine use of the iBB toensure consistent small bowel displacement and patient setup while irradiating malignant tumours in the pelvis.
Results: The average residual difference in patient position calculated using the bony anatomy auto-match was AP = -1.07 ± 2.25 mm, SI = 0.85 ±1.45 mm and LR = -0.07 ± 1.11 mm. The grading associated with the normalized Likert response scores for SB displacement and consistency in SB
displacement were as follows: moderate (0.4 to 0.6), good (0.6 to 0.8) andexcellent (0.8 to 1.0). The average scores taken over the 12 data sets were0.72 (displacement) and 0.73 (consistency) for RO1 and 0.79 and 0.83 forRO2. Using the findings of this investigation we developed a QA program forusing the iBB which encompasses the initial patient set-up at CT simulation,isocenter selection, treatment set-up as well as CBCT acquisition frequency.
These details will be presented.
Conclusions: Our work resulted in the development of an ergonomically iBB
which provides robust patient set-up resulting in satisfactory displacement of
the small bowel for rectal cancer patients during radiation treatment
1065 poster
P53 AS PREDICTIVE BIOMARKER IN LOCALLY ADVANCED RECTALCANCER TREATED WITH PREOPERATIVE CHEMORADIOTHERAPY
S. Stojanovic-Rundic1 , M. Micev2 , I. Popov3 , Z. Krivokapic4 , D. Gavrilovic5
1
I NSTITUTE FOR O NCOLOGY AND R ADIOLOGY OF S ERBIA, Radiotherapy,
Belgrade, Serbia
2
I NSTITUTE FOR D IGESTIVE D ISEASE , C LINICAL C ENTER OF S ERBIA,
Pathology, Belgrade, Serbia
3
I NSTITUTE FOR O NCOLOGY AND R ADIOLOGY OF S ERBIA, Medical
Oncology, Belgrade, Serbia
4
I NSTITUTE FOR D IGESTIVE D ISEASE , C LINICAL C ENTER OF S ERBIA,
Surgery, Belgrade, Serbia
5
I NSTITUTE FOR O NCOLOGY AND R ADIOLOGY OF S ERBIA, Data Centre,
Belgrade, Serbia

Purpose: This study was performed to investigate correlation between value

PALLIATIVE RADIOTHERAPY INSTEAD OF SURGERY IN SYMPTOMATIC RECTAL CANCER WITH SYNCHRONOUS UNRESECTABLE METASTASES
D. Tyc-Szczepaniak1 , L. Wyrwicz2 , M. Olszyna-Serementa1 , L. Pietrzak1 , J.
Kryński2 , A. Rutkowski2 , K. Bujko1
1
M ARIA S KLODOWSKA -C URIE M EMORIAL C ANCER C ENTRE, Department ofRadiotherapy, Warsaw, Poland
2
M ARIA S KLODOWSKA -C URIE M EMORIAL C ANCER C ENTRE, Department of
Gastrointestinal Cancer, Warsaw, Poland
Purpose: Apart from chemotherapy, palliative primary tumour resection or
diverting stoma creation is currently a standard method of management forpatients with symptomatic rectal cancer and nonresectable synchronous distant metastases. The potential advantage of using conservative treatment
over surgery is to avoid stoma and postoperative complications. In the frameof a prospective study, we aim to answer the question as to whether surgery
can be avoided by using short-course pelvic irradiation and immediate consolidation chemotherapy.
Materials: Patients with symptomatic mid and low-lying rectal cancer and unresectable distant metastases received 5 x 5 Gy to the pelvis and oxaliplatinebased chemotherapy after one week. Planning target volume included only
gross tumour with a margin. The effectiveness of local treatment was assessed by the self-administered questionnaires filled out by patients.
Results: All twenty-one consecutive patients (planned sample size) who fulfilled the entry criteria were enrolled into our study between December 2009
and September 2010. Tumour obstructive symptoms were most frequently
reported (62%). One month after radiotherapy, 38% of patients reported complete relief from pelvic symptoms, 57% reduction of symptom’s intensity and
5% (one patient) had stoma creation. At the last follow-up, two patients (10%)
had stoma. The remaining 19 patients (90%) did not need surgery duringfollow-up which ranged from 1 to 9 months; with the median of 6 months. In
the last questionnaire, 37% of these patients reported complete relief frompelvic symptoms, 47% partial response and 16% improvement with consecutive progression of symptoms but without a need for surgery. Seven patientsdied within 1 to 8 months (median 3) post radiation. Of these, six patients had
their pelvic symptom controlled and did not require surgery and one patient
had a stoma. Updated results will be presented at the conference.
Conclusions: For symptomatic rectal cancer patients with unresectable distant metastases, pelvic radiation with consolidation chemotherapy represents
a promising approach.
1067 poster
POSTOPERATIVE
IRINOTECAN/CISPLATINCHEMOTHERAPYFOLLOWED BY CHEMORADIATION FOR STAGE IB-IIIB GASTRICCANCER.
E. Diamantidou1 , L. Vini2 , D. Hourmouzi3 , C. Kakana4 , A. Silyvridou5
1
I NTERBALKAN M EDICAL C ENTER, Medical Oncology, Thessaloniki, Greece
2
ATHENS M EDICAL C ENTRE, Radiation Oncology, Athens, Greece
3
I NTERBALKAN M EDICAL C ENTER, Radiology, Thessaloniki, Greece
4
I NTERBALKAN M EDICAL C ENTER, Medical Physics, Thessaloniki, Greece
5
ATHENS M EDICAL C ENTRE, Medical Physics, Athens, Greece
Purpose: The aim of this prospective study was to evaluate toxicity
and efficacy of postoperative adjuvant sequential Irinotecan and Cisplatin

S 397

chemotherapy, followed by Capecitabine-based chemoradiation in patientswith resected stage IB-IIIB gastric carcinoma.
Materials: Patients with localized stage IB-IIIB resected gastric carcinoma, one month after gastrectomy, were treated with 3-weekly Irinotecan(65mg/m2) and Cisplatin (30mg/m2) for two courses, followed by 3D conformally planned radiotherapy (total dose 5040cGy in 28 fractions) concurrently
with Capecitabine 1000mg/m2 divided in two doses as radiosensitizer. Patients received an additional course of chemotherapy upon completion of radiation therapy.
Results: Between April 2005 and December 2009, 84 patients were enrolled
in the study. There were 53 men and 31 women with median age at diagnosis of 56 years (range 37-78 years). Seventy-one of them had total gastrectomy with extensive lymphadenectomy and thirteen had subtotal gastrectomy.
The most common hematological toxicity was grade 2 neutropenia in 60% of
the patients, Grade 2 aneamia and thrombocytopenia occurred in 35% and
38% and Grade 2 nausea and vomiting in 40% of the patients. With a median follow-up of 39 months (9-58 months) 6 patients relapsed locally (7%),
4 developed small volume peritoneal deposits (5%) and 7 developed distantmetastases (8%). Five year overall survival was 66% and disease-free survival 48%.
Conclusions: Our results, indicate that the combination of postoperative Irinotecan and Cisplatin chemotherapy followed by chemoradiation(Capecitabine-based) is an effective and safe regimen with moderate toxicity
for patients with resected adenocarcinoma of the stomach.
1068 poster
PREOPERATIVE CAPECITABINE, RADIATION AND BEVACIZUMABIN RECTAL CANCER: FINAL RESULTS OF THE CRAB PHASE II
TRIAL
V. Velenik1 , J. Ocvirk2 , M. Music3 , M. Bracko4 , F. Anderluh1 , I. Oblak1 , I.
Edhemovic5 , E. Brecelj5 , M. Kropivnik3 , M. Omejc6
1
I NSTITUTE OF O NCOLOGY L JUBLJANA, Department of Radiation Oncology,
Ljubljana, Slovenia
2
I NSTITUTE OF O NCOLOGY L JUBLJANA, Department of Medical Oncology,
Ljubljana, Slovenia
3
I NSTITUTE OF O NCOLOGY L JUBLJANA, Department of Radiology, Ljubljana,
Slovenia
4
U NIVERSITY MEDICAL CENTER, Department of Pathology
5
I NSTITUTE OF O NCOLOGY L JUBLJANA, Department of Surgery, Ljubljana,
Slovenia
6
U NIVERSITY MEDICAL CENTER, Department of Surgery
Purpose: We assessed the efficacy and safety of adding bevacizumab (Bev)
to standard, capecitabine-based neoadjuvant radiochemotherapy (CRT) to
increase the pathological remission rate of locally advanced rectal cancer as
primary end point.
Materials: Enrolled patients (pts) with MRI-confirmed stage II/III rectal cancer were treated with an infusion of Bev (5 mg/kg) 2 weeks prior to neoadjuvant CRT, followed by Bev 5 mg/kg on week 3, 5, 7 and capecitabine 825
mg/m2 bid including weekends during RT. RT was administred at 50.4 Gy(25x1.8 Gy with boost 3x1.8 Gy, 3d conformal technique), starting on week
3. Total mesorectal excision was scheduled 6-8 weeks after completition of
CRT. Tumor regression grades (TRG) were evaluated on surgical specimens
according to Dworak. The primary endpoint was complete pathological response (pCR; TRG 4).
Results: A total of 60 pts were eligible for analysis. Median age was 60(range: 31-79) years, 64% of pts were male. Three pts presented with stage
T2 (4.9%), 53 with stage T3 (86.9%), 5 with stage T4 (8.2%), and lymph
node involvement was detected in 49 pts (80.3%). In 28 pts (45.9%) tumor
invaded the mesorectal fascia. The median tumor distance from anal verge
was 6 (range: 0-11) cm.Dose eduction or treatment interruption was requiredfor 7 pts (11.6%) due to grade 2 (n=2) and grade 3 (n=2) leukopenia, grade
3 diarrhea (n=1), grade 3 (n=1) and grade 4 (n=1) vascular toxicity. Other
grade 3 toxicities included dermatitis (n=6), proteinuria (n=4) and hypertension (n=1). Treatment was terminated in 1 pt due to withdrawal of the informed consent.Radical resection was achieved in 57 pts (95%) and 42 pts(70%) had sphincter preserving surgery. TRG 4 (pCR) was recorded in 8 pts(13.3%) and TRG 3 in 9 pts (15%). T-, N- and overall downstaging rates were46.7%, 65% and 75%, respectively.Thirty-eight pts (62.3%) developed perioperative complications, most common delayed wound healing (n=18, 30%),
infection/abscess (n=12, 20%) and anastomotic leak (n=7, 11.7%). Six pts
required surgical reintervention for leak (n=3), abdominal abscess (n=2) andpneumothorax (n=1).Fifty pts (83.3%) received postoperative chemotherapy.
Conclusions: The addition of Bev to standad capecitabine-based preoperative CRT is feasible and well tolerated. The high rate of radical resections
suggests its potential effect on tumor downstaging. However, it is associatedwith considerable toxicity and with no clinically relevant increase in pCR rate.
Longer follow-up is needed to assess the impact on other efficacy endpoints.

S 398

T ESTISR ECTAL CANCER

1069 poster
PREOPERATIVE RADIOCHEMOTHERAPY WITH CAPECITABINEVERSUS RADIOTHERAPY ALONE IN PATIENTS WITH LOCALLYADVANCED RECTAL CANCER
I. Mihaylova1 , V. Parvanova1 , N. Dimitrova2 , G. Kurteva3 , R. Lazarov4
1
N ATIONAL H OSPITAL OF O NCOLOGY, Clinic of Radiotherapy, Sofia,
Bulgaria
2
N ATIONAL H OSPITAL OF O NCOLOGY, Cancer Register, Sofia, Bulgaria
3
N ATIONAL H OSPITAL OF O NCOLOGY, Clinic of Oncology, Sofia, Bulgaria
4
TOKUDA H OSPITAL S OFIA, Sofia, Bulgaria

Purpose: Combined modality therapy consisting of surgery, radiation therapy
and chemotherapy is recommended for the majority of patients with stage
II-III rectal cancer. Preoperative radiotherapy combined with 5FU continuous infusion is considered as the standard treatment in such cases. Oral
capecitabine is replacing continuous infusion with 5FU. The purpose of thisstudy is to evaluate the results obtained with preoperative radiochemotherapy
with capecitabine (RCHT) v/s radiotherapy (RT) alone in terms of pathologicalcomplete response, tumor downstaging, distant metastases, local recurrence
and observed survival rate.
Materials: 85 patients with locally advanced rectal cancer stage II and III,age 40 to 75 (mean age 57) were treated for the period 2005 - 2010 in the
Department of Radiotherapy. The follow up period of these patients was
between 2.17 to 59.43 months (mean follow up - 31.49 months). Staging
was performed with CT of abdomen and pelvis, endorectal ultrasound and
MRI. The patients were randomized in two groups. In the first group (RCHT),
33 patients were treated with radiotherapy in combination with Capecitabine
825mg/m2 /12h daily, during the complete course of the radiation. In the second group (RT), 52 patients were treated with radiotherapy alone, with box"
technique on 60 Co, or on LINAC to total dose of 50Gy, in daily dose of 2Gy,
5 times weekly. Clinical staging T in the first group was as follows: T3-18(54.5%), T415 (45.4%) and the second group T3-20 (38,4%), T4-32 (61,5%).
Following the preoperative RCHT and RT treatment all patients undergo surgical procedure using the method of total mesorectal excision. The observed
survival rate was evaluated using the Kaplan-Maier method and Log rank test.
Results: The rate of pathologic complete response in RCHT group was 9%,
versus 2% in RT group. Tumor downstaging in RCHT group was 80%, versus
68% in RT group. The rate of local recurrence in RCHT group was 24.2%,
versus 38% in RT group. The rate of distant metastases in RCHT group was
18%, versus 25% in RT group. The observed survival rate in RCHT groupwas 76.9% versus 72.7% in RT group (p=0.837). The mean survival time is38.27 months (95% CI: 33.05 43.49) in the RCHT group versus 48.04 months(95% CI: 42.40 53.68) in the RT group.
Conclusions: RCHT with capecitabine is an adequate therapy in patientswith rectal cancer in stage II-III. It provides better pathologic complete response, tumor downstaging and local control versus radiotherapy alone.
There is no statistically significant difference in both groups regarding theobserved survival rate.
1070 posterRESPONSEWITHOXALIPLATIN
BASEDNEOADJUVANTCHEMOTHERAPY BEFORE CHEMORADIATION IN LOCALLYADVANCED RECTAL CANCER
A. S. Kazmi1 , W. I. Ali2 , A. A. Syed3 , M. A. Yusuf4 , S. Hameed2 , U.
Majeed2 , M. A. Shah2 , I. Haider2 , A. Jamshed2
1
S HAUKAT K HANUM M EMORIAL C ANCER H OSPITAL & R ESEARCH C ENTRE,
Department of Medical Oncology, Lahore, Pakistan
2
S HAUKAT K HANUM M EMORIAL C ANCER H OSPITAL & R ESEARCH C ENTRE,
Department of Radiation Oncology, Lahore, Pakistan
3
S HAUKAT K HANUM M EMORIAL C ANCER H OSPITAL & R ESEARCH C ENTRE,
Department of Surgical Oncology, Lahore, Pakistan
4
S HAUKAT K HANUM M EMORIAL C ANCER H OSPITAL & R ESEARCH C ENTRE,
Department of Internal Medicine, Lahore, Pakistan
Purpose: Neoadjuvant chemoradiation (CRT) with 5-FU in locally advanced
rectal cancer has shown improvement in local control and survival. Local control is related to pathological response and achieving clear surgical margins.
Primary aim of our study is to see pathological complete response (pCR)
rate using oxaliplatin and capecitabine (CapOx) as induction chemotherapy
followed by chemo radiation prior to TME surgery in AJCC stage III/IV rectal
tumors. Secondarily overall APR rate, circumferential margins and toxicities
were assessed.
Materials: Seventy two patients analyzed retrospectively from August 2007
August 2010, including 65% (47) males and 35% (25) females with a medianage of 42 years (Range 18 75). All were locally advanced adenocarcinomasof the rectum staged as T2N+ 1.4% (1), T3N0 4% (3), T3N+ 69% (50), T4N0
1.4% (1) and T4N+ 24% (17). On average 3 to 4 cycles of CapOx, using 130
mg/m2 Oxaliplatin on day 1 with 1000mg/m2 BID capecitabine for two weeks
repeated every 21 days was given as neoadjuvant chemotherapy followedby concurrent chemoradiation using capecitabine 825 mg/m2 BID. Radiationdose 50.4Gy over 5 and half weeks at the rate of 1.8Gy/day was delivered via
three field technique. Resectability and preoperative down staging was as-

sessed through MR pelvis after 5 weeks completing chemoradiation. Surgery
was done within 6 8 weeks and pathological response established on final
histopathology.
Results: Pathological complete response (pCR) noted in 28% (20), residual tumor seen in 61% (44) while 11% (8) were unresectable. Proportion oftumors within 5cm from anal verge was 51% (37) and the overall APR rate
was 29% (21). Negative circumferential margins were achieved in 64% (46).
Toxicity profile showed grade 3/4 diarrhea in 11% (8), grade 3/4 handfoot syndrome in 11% (8) and grade 3/4 skin reactions in 14% (10). In haematological
toxicities grade 3/4 leucopenia was seen in 7% (5) and grade 3/4 thrombocytopenia in 4.2% (3) patients. The worst neuropathy seen in oxaliplatin group
was grade 2, present in 11% (8) patients.
Conclusions: Improvement in pathological complete response (pCR),
achieving more negative circumferential surgical margins and decrease in
overall APR rate with acceptable toxicity by the addition of Oxaliplatin andcapecitabine in neoadjuvant setting is encouraging and merits further investigations in clinical trials.
1071 poster
SHORT-COURSE PREOPERATIVE RADIOTHERAPY COMBINEDWITH CHEMOTHERAPY IN RESECTABLE LOCALLY ADVANCEDRECTAL CANCER: A MONO-INSTITUTIONAL PHASE II STUDY.
P. Ciammella1 , M. Galeandro1 , M. P. Ruggieri1 , N. D Abbiero1 , T. Palmieri1 ,A. Giunta2 , M. C. Banzi3 , E. Donini1 , C. Iotti1
1
A RCISPEDALE S. M ARIA N UOVA, Radiation Oncology, Reggio Emilia, Italy
2
A RCISPEDALE S. M ARIA N UOVA, Surgery, Reggio Emilia, Italy
3
A RCISPEDALE S. M ARIA N UOVA, Oncology Clinic, Reggio Emilia, Italy
Purpose: The present study was undertaken to evaluate whether shortcourse preoperative radiotherapy combined to chemotherapy is effective on
local failure rates. This protocol differs from the other trials in two important
aspects: the neo-adjuvant RT was combined with neo-adjuvant chemotherapy treatment and the total dose of RT was modified from 25 Gy in five fractions (Swedish protocol) to 20 Gy in five fractions, to potentially reduce thepotentially higher acute toxicity (for the addition of the chemotherapy), maintaining the total treatment time of one week.Management of resectable rectal
cancer is a multidisciplinary treatment, because, although surgery still plays
a fundamental role, the addition of radiation therapy and chemotherapy, in
pre-operative or adjuvant setting, results in significantly improved local control(LC) and overall survival (OS) in comparison to the surgery alone. Several trials has shown that the pre-operative radiation therapy (RT) door to a diminution of the risk of local relapse also of 50-70%. The most frequent regimens
in the pre-operative setting of patients with resectable rectal cancer are conventionally fractionated chemo-radiation therapy (45-50 Gy in 1.8-2 Gy per
fraction) with delayed surgery or short-course irradiation (25 Gy in 5 fractions)with immediate surgery, with similar results in terms of long-term survival, local control and late morbidity. The present study was undertaken to evaluate
whether short-course preoperative radiotherapy combined to chemotherapy
is effective on local failure rates. This protocol differs from the other trials in
two important aspects: the neo-adjuvant RT was combined with neo-adjuvant
chemotherapy treatment and the total dose of RT was modified from 25 Gy
in five fractions (Swedish protocol) to 20 Gy in five fractions, to potentiallyreduce the potentially higher acute toxicity (for the addition of the chemotherapy), maintaining the total treatment time of one week.
Materials: The patients with resectable locally-advanced rectal cancer enrolled between 1997 and 2006 in a prospective mono-institutional study of
pre-operative SC-RT were analyzed. The most important eligibility criteria
were: biopsy-proven resectable rectal cancer, maximum 12 cm above dentate line (upper limit), and no evidence of sphincter involvement. The treatment was:- neo-adjuvant chemotherapy (modified FOLFOX6) administered
every 2 weeks for 4 cycles.- pre-operative SC-RT administered 1 week after
chemotherapy completion, delivering 20 Gy in 4 fractions over 1 week. - ananterior resection (AR) or an abdominoperineal resection (APR), with total
mesorectal excision, was performed immediately in the following week.- adjuvant 5-FU based chemotherapy was planned for pathological stage UICC
≥ II.The LC, overall survival (OS), disease-free survival (DFS), and early andlate complications (RTOG scale) were analyzed.

Results: 67 patients were enrolled in this study. Median age was 64 years
and male:female ratio was 1,4:1. The clinical UICC stage classification was
48% stage II and 52% stage III. Tumor location was the upper, middle andlower third of the rectum in 17%, 51% and 32% of the patients respectively.
Chemotherapy and RT were well tolerated and completed in all the patients.
After AR (73%) and APR (27%), the pathology stages were I in 25%, II in
42%, and III in 33% of patients. Stable disease was obtained in 24 patients(36%), reduction of staging disease in 34 patients (50.7%) and progressionin 9 cases (13.3%). No complete response was achieved. Complete local resection of the rectal cancer was achieved in 100% of cases, with median distance margins of 44 mm (range 7-120 mm). Perioperative mortality

was absent; early mild post-operative complications were observed in 24%of the cases (anastomotic leakage, anastomotic stenosis and wound infection). Late post-operative complications were observed in 16 patients (23%).
Re-operation due to post-operative complications was required in one patient
for anastomosis stenosis 15 months after surgery. Administration of adjuvant chemotherapy was indicated in 21 patients. A total of four locoregional
out RT fields recurrences were observed resulting in a five-year LC of 94%.
Locoregional recurrences were observed between 14 and 48 months fromsurgery. Two recurrences developed in the pre-sacral region and two in theregional lymph nodes. A total of 11 systemic recurrences were observed resulting in a five-year DFS of 84%, with median time to systemic progressionof 24 months. Seven patients developed liver metastes and five patients lungmetastases. After median follow-up of 84 months the five-year OS was 68%.
Late toxicity > grade II was observed in 9 % of the patients. 17 patients diedduring follow up and cause of death was progression of rectal cancer (n=8),
intercurrent disease (n=5) and unknown (n=4).
Conclusions: The preoperative SC-RT combined to chemotherapy for
locally-advanced resectable rectal cancers was well tolerated, with favourable
outcomes. The current small monocentric study was a pilot for a larger
prospective study to determine the difference in terms of disease control endpoints and quality of life between long course and short course pre-operative
RT, both associated with chemotherapy treatment.
1072 poster
STEREOTACTIC BODY RADIATION THERAPY FOR COLORECTALLIVER METASTASES
C. Menichelli1 , S. Masciullo1 , F. Casamassima1 , I. Bonucci1 , L. Masi1 , R.
Doro1
1
U.O.R ADIOBIOLOGIA C LINICA U NIVERSITÀ DI F IRENZE, Firenze, Italy
Purpose: To evaluate the effectiveness of image-guided stereotactic body radiation therapy (SBRT) for hepatic metastases from colorectal cancer (CRC).
Materials: A total of 53 patients (18 female, 35 male) with median age of 66
years (37-85) were treated in our Institution with SBRT for CRC liver metastases (n=92). Primary tumor was controlled by surgery in all but four cases.
Median interval between diagnosis and liver metastases appearance was
9 months (0-78). In 21 patients liver was involved at onset of disease andsynchronous metastases were treated with surgery or thermoablation. Median interval diagnosis-metastases treated with SBRT was 31 months (7-73).
Three patients underwent second SBRT treatment for new hepatic lesions.
The median number of hepatic metastases at the time of first SBRT course
was 1 (1-4). Thirty-five patients presented extrahepatic metastases and 35
received prior or following chemotherapy within six months of radiotherapy.
GTV was delineated on two CT scans acquired in expiration and inspiration,in order to obtain an ITV. PTV was obtained adding an 3 mm isotropic margin.
Median PTV was 4.5 cc (4-632). Median prescription dose was 36 Gy in threefractions (9-12.5 Gy) at 67% isodose line (n=54) or at isocenter (n=38). A
Cone-Beam CT was acquired before each fraction for setup corrections andisocenter verification, using diaphragm contour (19 Pts) or implanted gold
fiducials (34 Pts). CTCAE v.4 and modified RECIST criteria was used for
toxicity and response evaluation.
Results: With median follow-up of 15.7 months (2-45), 25 patients are alive.
Kaplan Meier OS at 2-years was 40%. Median survival among deceased patients was 14.4 months. No statistical difference between patients with hepatic only or extrahepatic disease was found (p=0.8). The 2-years actuarial
local control (LC) was 66.7% (79 evaluable lesions). Overall, were observed
17 local failure in 14 patients, with median "in field" time-to-progression (TTP)of 7 months (3-17). Significant difference (p=0.001) was found on the LC comparing alignment by fiducials or diaphragm contour. However, in the fiducials
group higher doses were given by virtue of the possibility of a more precise
set-up (median dose 37.5 Gy at 67% isodose line Vs. 36 Gy at isocenter).
There were hepatic relapse "out field" in 21 patients (median TTP 9 months)
and extrahepatic in 24 (median TTP 9 months); 11 patients showed both
intra- and extrahepatic failure. Acute GI toxicity grade ≤2 occurred in 6 patients (nausea, vomit, gastritis) and late toxicity in one case (gastrointestinal
ulceration medically recovered).
Conclusions: CRC patients with liver metastases fare well after imageguided SBRT. In particular, higher local control can be obtained with joined
use of intrahepatic implanted fiducials and dose escalation. These results
lead to consider the SBRT an effective locoregional therapy for the treatmentof not resecable hepatic metastases.
1073 poster
STEREOTACTIC BODY RADIATION THERAPY FOR LIVERMETASTASES: INFLUENCE ON LOCAL CONTROL OF TARGETSURROGATES FOR ALIGNMENT AND DOSE LEVELS
F. Casamassima1 , S. Masciullo1 , C. Menichelli1 , L. Masi1 , R. Doro1 , I.
Bonucci1
1
U.O.R ADIOBIOLOGIA C LINICA U NIVERSITÀ DI F IRENZE, Firenze, Italy
Purpose: To evaluate the influence on local control of the use of implanted

S 399

gold fiducial markers as target surrogate for stereotactic IGRT in comparison
to diaphragm contour alignment.
Materials: Ninety-two patients (43 f, 49 m) with median age of 65 years (3785) were treated in our Institution by SBRT for liver metastases (n=150). Primary tumor was colorectal in 50 Pts, breast in 15, pancreas in 7, other in
20. Ten patients underwent other SBRT-courses for new lesions. The median
number of hepatic metastases at the time of first SBRT course was 2 (16). In 50% of cases there were extrahepatic metastases. Sixty-one patients
received prior or following chemotherapy within six months of radiotherapy.
GTV was delineated on two CT scans acquired in expiration and inspiration,in order to obtain an ITV. For 70 Pts a spirometer (Elekta ABC) was used forrespiratory motion monitoring during image acquisition and treatment. For 58
Pts 2-4 fiducial markers were implanted by CT-guidance in the proximity oflesion. Median PTV was 35.2 cc (4-632). Median prescription dose was 36
Gy in three fractions (9-12.5 Gy) at isodose line ranging from 67% to 100%.
Maximum dose at isocenter ranged from 30 to 66 Gy in three fractions (median 39). A number of 3-16 coplanar arcs were utilized and the planned dose
was delivered by a 6 MV Elekta Synergy equipped with dynamic mMLC. A
Cone-Beam CT was acquired before each fraction for setup corrections andisocenter verification, using diaphragm contour (34 Pts) or implanted fiducials(58 Pts). CTCAE v.4 and modified RECIST criteria was used for toxicity assessment and "in field" response evaluation.
Results: With median follow-up of 13 months (2-43), the Kaplan Meier OS
at 1- 2 years was 65% and 32%. The 1- and 2-years actuarial local control (LC) was 86% and 72%. Overall, there were 24 local failure in 18 Pts,
with median time-to-progression of 12 months. No differences was found for
LC rates between colorectal and breast metastases. Comparing the impactof alignment modalities on local control, there was a significant difference
between fiducial-alignment and diaphragm-alignment (1-year LC= 90% Vs.
64%, p=0.009). However, in the fiducials group higher doses were given by
virtue of the possibility of a more precise set-up (maximum dose median 57
Gy vs. 36 Gy). Acute toxicity was GI of grade ≤2 in 9 Pts, late toxicity wasobserved in 3 Pts as gastrointestinal ulceration medically recovered.
Conclusions: In our experience image-guided SBRT for liver metastases appears effective and with mild and acceptable acute/late toxicity. Local control
is clearly influenced by the use of fiducial markers as target surrogate andby the dose escalation, but it is difficult in this series to establish the relative
weight of these two factors.

Testis1074 poster
BONE MARROW-SPARING INTENSITY-MODULATED RADIATIONTHERAPY FOR STAGE I SEMINOMA
T. Zilli1 , C. Boudreau1 , R. Doucet1 , M. Alizadeh1 , C. Lambert1 , T. V.
Nguyen1 , D. Taussky1
1
CHUM - C AMPUS N OTRE -DAME, Radiation Oncology, Montréal, Canada
Purpose: A direct association between radiotherapy dose, side-effects andsecondary cancers has been described in patients with seminoma. A
treatment planning study was performed in order to compare computed
tomography-based traditional radiotherapy (CT-tRT) versus bone marrowsparing intensity-modulated radiation therapy (BMS-IMRT) in patients with
Stage I seminoma.
Materials: We optimized in 10 patients a CT-tRT and a BMS-IMRT treatment plan to deliver 20 Gy to the para-aortic nodes. CT-tRT and IMRT consisted of anteroposterior-posterioranterior parallel-opposed and seven nonopposed coplanar fields using 16 and 6-MV photon energies, respectively.
Dose-Volume Histograms for clinical target volume (CTV), planning target
volume (PTV) and organs at risk (OAR) were compared for both techniques
using Wilcoxon matched-pair signed rank-test.
Results: Dmean to CTV and PTV were similar for both techniques, even if
CT-tRT showed a slightly improved target coverage in terms of PTV-D95%(19.7 vs. 19.5 Gy, p = 0.005) and PTV-V95% (100 vs. 99.7%, p = 0.011)
compared to BMS-IMRT. BMS-IMRT resulted in a significant reduction (5.2
Gy, p = 0.005) in the Dmean to the active bone marrow (ABM). The V100%
and V75% of the OAR were reduced with BMS-IMRT by: ABM-V100% =51.7% and ABM-V75% = 42.3%; bowel-V100% = 15.7% and bowel-V75%= 16.8%; stomach-V100% = 22% and stomach-V75% = 27.7%; pancreasV100% = 37.1% and pancreas-V75% = 35.9% (p = 0.005 for all variables).
Conclusions: BMS-IMRT reduces markedly the dose to the OAR comparedto CT-tRT. This should translate into a reduction in acute and long-term toxicity, as well as into the risk of secondary solid and hematological cancers.

S 400B RACHYTHERAPY: I MAGE GUIDANCET ESTIS1075 poster
TESTICULAR SEMINOMA: A 12 YEARS EPIDEMIOLOGICALREVIEW OF THE EXPERIENCE OF A SINGLE INSTITUTION.
D. Fonte1 , P. Meireles1 , A. Costa2 , L. Alves1 , G. Pinto3
1
H OSPITAL S ÃO J OÃO, Radiation Oncology, Porto, Portugal
2
H OSPITAL S ÃO J OÃO, Oncology, Porto, Portugal
3
H OSPITAL S ÃO J OÃO, Direction of Radiation Oncology Department, Porto,
Portugal
Purpose: Analysis of survival, locoregional control and toxicity in a group ofpatients with testicular seminoma treated according to the initial stage. The
purpose of this study was to review the experience of a single institution inseminoma treated with adjuvant radiotherapy, in the last 12 years.
Materials: This is a retrospective observational study of patients with seminoma treated during the period between Jan/ 1998 to Jun/ 2010. It reports the
epidemiological analyses, clinical and therapeutic aspects of all seminomas
treated in our department, during this period.
Results: This study included 31 patients with testicular seminoma. Medianage was 31 years (21-45). All the patients were submitted to surgery (onlytherapeutic modality in two cases that refused adjuvant treatment) and the
majority (87,1%) received adjuvant radiotherapy (total dose 27-30 Gy) to thelombo-aortic and pelvic chains. 6,5% of patients (stages IIc-IIIc) received also
adjuvant chemotherapy (BEP). The most common stage of the tumor was I(67,7%), followed by stage II (16,1%). With a median follow-up time of 29
months (2-161 months), the rate of overall and specific survival in stages I
and II was 100%. No "in-field" recurrences occurred. Only one (3,2%) patient
relapsed and this was the case of one of the patients submitted to surgery
with no adjuvant treatment. No patient developed a second primary tumor.
During RT, grade I-II gastrointestinal toxicity was reported by 19 (61,3%) patients, according to CTCAE (V4.03) tables.
Conclusions: The results presented in this retrospective study are similar
to those obtained by larger series. The treatment with RT was overall welltolerated. According to these results, the association of surgery with RT in
testicular seminomas in early stages can result in optimal locoregional control
and large survival with an acceptable toxicity.

11th Biennial Physics and
RTTBrachytherapy: Image guidance
1076 poster
3-D IMAGING IN GYNAECOLOGICAL BRACHYTHERAPY
D. Larsen1 , C. Lee Dann1
1
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Radiation
Oncology, Herlev, Denmark
Purpose: In the brachytherapy unit at our large radiotherapy clinic is it highly
prioritised to optimise our imaging procedure for treating cancer patients. In
the brachytherapy unit we have recently installed an imaging device, whichenables us to perform on-board 3-D imaging directly at the treatment couch.
The ceiling suspended C-arm performs digital fluoroscopy and radiographs
along with Cone Beam CT (CBCT). Together with the MRI scanner dedicatedfor radiotherapy it is possible to plan and verify treatments for cervical cancer
patients in 3-D. The purpose is to make online 3-D evaluations of our standard
treatment and to verify the MRI-based plans and set-ups in more advanced
treatments without moving the patients. It is possible to fusion MRI with CBCT
in order to verify the planning and adapt the treatment if necessary.
Materials: The first task was to create a functional treatment unit and a treatment protocol for cervical cancer. The process involved installing and training
in the use of the equipment and creating a treatment protocol. It was necessary to develop add-ons for the imaging equipment, the Allura FD 20®from
Philips, and to prepare a new treatment set-up. In order to be able to perform
CBCT and MRI with the applicator in situ, it was necessary to purchase CTand MRI-compatible applicators. We chose the Vienna®applicator from Nucletron. The image set-up provides on-board imaging with the use of CBCT.
This results in a number of advantages such as enhanced reliability of verification, a more efficient workflow and a more patient friendly procedure.
The CBCT takes only one minute to perform, and our standard verification
method, radiographs in 2-D, is now followed by 3-D images with soft tissue
information. This allows us to be able to perform the treatment set-up withhigh accuracy and instant verification. We are in the process of implementing
interstitial treatments of cervical cancer to patients with more advanced tumours. Up until now we have treated ten cervical cancer patients in stage IIb
with the use of the Vienna applicator. During the first brachytherapy treatment
we perform CBCT and MRI with the catheter in situ. The following treatments
are verified only by CBCT.
Results: Today we use the 3-D imaging as a standard in brachytherapy ofcervical cancer. This set-up method is optimal in order to verify the positionof the treatment applicator. The dose planning in soft tissue areas is instantand precise, so the dose calculation for both the tumour and risk organs is
optimal. As a result of this we are developing our treatment method in order
to be able to perform interstitial treatments in the future.
Conclusions: Without prolonging the treatment procedure, we perform a true
3-D image of the dose distribution in treating cervical cancer. The perspective
is to be able to perform adaptive brachytherapy.
1077 poster
DEFORMABLE REGISTRATION FOR BLADDER DOSE ACCUMULATION DURING FRACTIONATED CERVIX CANCER BRACHYTHERAPY
T. Aagaard1 , K. N. Østergaard2 , S. K. Nielsen3 , L. Fokdal4 , J. C.
Lindegaard5 , K. Tanderup4 , T. S. Sørensen6
Å RHUS S YGEHUS, Department of Medical Physics - Research, Århus,
Denmark2
Å RHUS U NIVERSITY, Computer Graphics Lab, Århus, Denmark
3
Å RHUS S YGEHUS, Department of Medical Physics and Radiation Safety,Århus, Denmark
4
Å RHUS S YGEHUS, Department of Oncology, Århus, Denmark
5
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
6
A ARHUS U NIVERSITY, Department of Computer Sciences, Aarhus C,
Denmark
1

Purpose: Assessment of total dose from several brachytherapy (BT) fractions
is currently performed by crude addition of DVH parameters the so called"worst case assumption". However, when hot spots are distributed differently
in succeeding BT fractions, this will be result in an overestimation of dose.
The purpose of this study was to use deformable registration to assess how
much the "worst case assumption" overestimates the dose.
Materials: 32 pts with locally advanced cervical cancer were analysed. All
patients received elective EBRT (45-50 Gy/25-30 fractions) and pulsed dose
rate BT (30-35 Gy/2 fractions 15-20 pulses) with MRI based planning foreach BT fraction. The bladder was contoured on both BT fractions (BT1 andBT2), and deformable registration between the two bladder contours was performed. The registration was based on surface mesh registration and energy
minimisation of an elastic surface membrane. Three landmarks were included
to constrain the deformation. The deformation was visually evaluated with regard to physiological plausibility. The deformation map was applied to theBT1 dose matrix to cumulate BT1 and BT2 dose. DVH parameters of theresulting 3D dose matrix were calculated and compared to those obtained by

S 401

addition of BT1 and BT2 DVH parameters.
Results: In 30/32 patients the deformable registration was successful. For
2 patients with irregular bladder surface it was not possible to obtain a consistent deformable registration. Addition of DVH parameters overestimatedthe bladder dose by median 1% and 5% for D2cc and D0.1cc, respectively
whereas the 75% quantile was 4% and 9%, respectively. Overestimation of
more than 10% and up to maximum 17% was found in 2/30 and 3/30 patientsfor D2cc and D0.1cc, respectively. Visual inspection of the dose distributions
indicated that the most significant overestimations were consistent with different location of the hot spot dose in BT1 and BT2.
Conclusions: Simple addition of DVH parameters provided a good estimateof total D2cc hot spot dose in the bladder. This indicates that D2cc was in
the same region of the bladder during both BT fractions for the majority ofpatients. D0.1cc showed more variation since half of the patients had an
overestimation of more than 5%. In conclusion, "the worst case assumption"
provides a good dose estimate for D2cc, whereas D0.1cc is less robust to thisapproximation.
1078 poster
IMAGE GUIDED BRACHYTHERAPY FOR CERVIX CARCINOMA:IMPACT OF MAGNETIC RESONANCE IMAGING
K. Peignaux-Casasnovas1 , A. Petitfils2 , G. Truc1 , E. Martin1 , J. Chamois1 ,A. Ligey1 , G. Crehange1 , C. Khouri1 , P. Maingon1 , D. Krause3
C ENTRE G EORGES -F RANÇOIS L ECLERC, Department of Radiation
Oncology, Dijon, France
2
C ENTRE G EORGES -F RANÇOIS L ECLERC, Department of Medical Physics,
Dijon, France
3
C ENTRE HOSPITALO - UNIVERSITAIRE DU B OCAGE, Department of Radiology, Dijon, France

1

Purpose: To compare target delineation with computed tomography (CT) versus magnetic resonance imaging (MRI) in cervical cancer brachytherapy.
Materials: Eleven patients underwent pulse-dose-rate brachytherapy forcervix carcinoma. They were treated by combined chemoradiation for locally advanced disease (n=9). Brachytherapy was planned one week after
completion of external beam irradiation. Both planning T2 weighted MRI andCT with section thickness of 3 mm were performed after Fletcher CT/MR applicator insertion. The same trained radiation oncologist contoured high-risk
clinical target volume (HR-CTV) and intermediate risk clinical target volume(IR-CTV) on CT and MRI according to GEC-ESTRO recommendations. The
HR-CTV included the whole cervix and extracervical residual tumour extension at the time of brachytherapy. The IR-CTV encompassed HR-CTV with a
1 cm margin around.
Results: Mean values of target volumes obtained on CT and T2 weighted
MRI were respectively 25.2 cm3 and 19.7 cm3 for HR-CTV and 95.2 cm3 and85 cm3 for IR-CTV. Target delineation on MRI was easier for the radiation
oncologist compared to CT and allowed a decrease in 22% of volume for
HR-CTV and 11% for IR-CTV. However this difference was not significant
probably due to the small number of patients.
Conclusions: CT delineation overestimates target volume. MRI allows abetter discrimination between normal tissues and residual disease and must
be the standard for CTV delineation for cervix cancer brachytherapy. The
impact on toxicity will be soon evaluated.
1079 poster
ROLE OF IN-VIVO DIODES DOSIMETRY FOR CRITICAL ORGANDOSE EVALUATION IN HDR BRACHYTHERAPY OF CERVIX CANCER
A. Hassouna1 , Y. Bahadur2 , C. Constantinescu1 , M. Ezzat1 , H. Naseem2 ,A. Naga1
1
K ING FAISAL S PECIALIST H OSPITAL, Oncology, Jeddah, Saudi Arabia
2
K ING A BDULAZIZ U NIVERSITY H OSPITAL, Radiology, Jeddah, Saudi Arabia
Purpose: The aim of the present study was to investigate the role of in-vivo
dosimetry using diodes as a quality assurance method for HDR brachytherapy of cervix cancer.
Materials: After calibration of the in-vivo dosimetric system, a phantom study
was performed for comparing the calculations results provided by the TPS
and measurements, in order to estimate the reproducibility and uncertainty of
the in-vivo dosimetry system. A series of 32 intracavitary brachytherapy implants with a prescribed dose of 7 Gy at point A were evaluated prospectively,
the differences between the calculated and measured doses were estimatedand the influence of a possible geometrical shift of the probe position wasinvestigated.
Results: The mean uncertainty of calibration factor of the in-vivo dosimetry
system was 1.9% (range 0.4% to 4.3%). The reproducibility of measurements using diodes was better than 0.5% over one week.For the rectum,
72/160 (45%) measurements showed a higher calculated dose, and a difference of more than 10% was found in 28/60 (48%) measurements. The
ratio of 1 cm3 rectal dose to the diode was 1.9 ± 0.6, and the ratio of the
ICRU reference rectal point dose to the diode was 1.8 ± 0.4.For the bladder,S 402B RACHYTHERAPY: PLANNING AND OPTIMIZATIONB RACHYTHERAPY: PLANNING AND OPTIMIZATION

15/32 (46%) applications showed a higher calculated dose, and a differenceof more than 10% was found in 18/32 (56%) measurements. The ratio of
1 cm3 bladder dose to the diode was 1.8 ± 0.7, and the ratio of the ICRU
reference bladder point dose to the diode was 1.2 ± 0.5.

Results: The maximum skin dose was reduced up to 12% and 21% for the
19 mm and 25 mm conical applicators, respectively. For a parallel-opposed
beam configuration, the 19 mm and 25 mm conical applicators reduced thetreatment time up to 34% and 17%, respectively, in comparison to a roundapplicator having the same diameter. Agreement between MC-simulated and
TPS-calculated dose distribution using the gamma-index test was > 99.95%
for 2.0 mm distance-to-agreement and 2.0% dose accuracy criteria. DVHs
(figure) generated using Pinnacle3 indicated that the conical applicators provided similar PTV coverage to the round applicators and reduced the maximum dose to skin, chestwall, and lung up to 27%, 42%, and 43%, respectively. The maximum PTV dimensions in the midplane of the compressedbreast covered by the 90% isodose line were obtained and may serve as
clinical guidance for applicator selection.

tumor, you should use proctostat with shields.2. A practical investigation. We
treated 27 patients for various tumors using 3 different applicators (aforementioned). On the basis of the previous investigation as well as of improvementof methods and technologies during patient treatment, we managed to develop the following groups of patients, with different treatment techniques.3
groups of patients with different sizes of tumors were selected. We using
various techniques for each groups.
Results: All patients tolerated the treatment well. The complete tumor
regress was observed in all patients. The reference points have clinical significance, but we do not have complete control over the tumor dose and theoverdose of normal tissues; therefore we introduced dose-volume parameters.
Conclusions: Thus, intracavitary therapy for anal cancer is the optimal variant of radiation therapy. It is the optimal treatment method with a minimalradiation load for surrounding tissues and critical organs. For each patient, a
treatment method is developed according tumor process configuration.
1082 poster
IMPROVING LDR PROSTATE IMPLANT PLAN EVALUATION
C. Knaup1 , P. Mavroidis2 , N. Papanikolaou3
1

CTRC @ UT HSC AT S AN A NTONIO, San Antonio, USA
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Stockholm,
Sweden3
C ANCER T HERAPY, San Antonio, TX, USA
2

Conclusions: In-vivo dosimetry using diodes can be an important method
for a quality assurance program for HDR brachytherapy of cervix, but clinicaldecisions should be made based on 3D image-based dose calculation.

Brachytherapy: planning and optimization
1080 poster
3D TREATMENT PLANNING OF CONICAL BREAST BRACHYTHERAPYAPPLICATORSUSINGCONVENTIONAL
TREATMENTPLANNING SOFTWARE
1
1
1
1
Y. Yang , C. Melhus , S. Sioshansi , M. Rivard
1

Conclusions: 3D dose distributions for the conical applicators have been
generated using both MC and a conventional TPS using a TG-43 hybrid
method. As the conical applicators reduced treatment time and provided
lower OAR dose, they may be a promising tool for accelerated partial breast
irradiation.
1081 poster
DOSE DISTRIBUTION DEVELOPMENT FOR ANAL CANCER INTRACAVITARY BRACHYTHERAPY
O. Kozlov1 , M. Chernykh1 , I. Gladilina1 , M. Nechushkin1 , D. Naumov1
1
N.N. B LOKHIN C ANCER R ESEARCH C ENTER, Brachytherapy Department,
Moscow, Russian Federation

Purpose: Low dose-rate brachytherapy of the prostate is one of the few techniques in radiotherapy were the delivered dose distribution is often considerably different from the planned. This is due to seed migration, prostate edema
and imperfect implant technique. This makes accurate treatment plan evaluation critical to future patient care decisions. If the tumor dose it too low, additional therapy may be required. Presently, treatment plan evaluation is basedon the mean, maximum and minimum doses given to the tumor and organs
at risk. These doses are compared to tables of known cure and complication endpoints to determine treatment effectiveness. However, these do notaccount for varying dose-rate effects, tumor repopulation and other biologicaleffects. By including the biological response in addition to dose distribution amore clinically relevant treatment plan evaluation may be obtained.
Materials: Ten LDR prostate cancer patients were evaluated in this study.
Each patient received a 120 Gy implant. Iodine-125 seeds were used andthe treatment plans were created on the Prowess treatment planning system.
The same day as the implant, each patient received a CT scan. This scan
was used to determine the post-implant position of the seeds. From these
CT images the post-implant plan was created. In the post-implant plan, theprimary tumor (PTV), bladder and rectum were contoured. The biologicallyeffective dose (BED) was calculated for each voxel using the physical dose
and the biological parameters of the appropriate organ. The BED was used
to determine the tumor control probability and the normal tissue complication
probabilities for the bladder, rectum and surrounding tissue.
Results: By incorporating radiobiological measures in the treatment planevaluation the predicted outcome of the therapy is concisely given by the response probabilities of each organ. The average tumor control probability was
95% and the complication probabilities for the bladder, rectum and surrounding tissue were 0.2%, 20% and 4% respectively. Not only do these measuresprovide a simpler means for evaluation, but since they include radiobiologicalfactors, the calculated response probabilities provide a more reliable estimateof clinical outcome.
Conclusions: The goal of this work was to create a more clinically relevant
treatment plan evaluation by incorporating radiobiological measures that estimate the actual therapeutic results. This resulted in a simpler descriptorof the overall treatment plan quality based only on the expected response
probabilities rather than having to consider many endpoint doses for several
organs.

T UFTS M EDICAL C ENTER, Radiation Oncology, Boston, USA

Purpose: AccuBoost is a non-invasive image-guided technique that serves
as an alternate to conventional electron beam boost for delivering partial
breast irradiation dose. The round applicator design has been changed byadding an internally-truncated conical shield and reducing of the source:skindistance while uniformly irradiating the target volume, minimizing skin dose,and reducing treatment time. This study evaluated the TG-43 hybrid technique of dose calculation against reference Monte Carlo (MC) simulations.
Materials: The conical applicators have internal diameters ranging from 5
cm to 8 cm in 1 cm increments and applicator heights of 19 mm or 25 mm.
Dose distributions were simulated and modeled using MCNP5 and Pinnacle
for all eight conical and four round applicators. Comparisons using a gammaindex test were performed between the MC-simulated and TPS-calculatedbrachytherapy dose distributions. Ten CT image datasets from five patientswith breast compressions in medial-lateral and cranial-caudal directions wereused for 3D treatment planning. Dose was delivered using parallel-opposed
AccuBoost beams and normalized to 1 Gy midway through the compressedbreast on the applicator central axis for all twelve aforementioned applicators.
DVHs for planning target volume (PTV) and organs at risk (OAR) such as
skin, chestwall, and lung were obtained and compared for each CT dataset.

Purpose: The purpose is to develop choice criteria of an optimal dose distribution for anal cancer treatment using 3 applicator sorts for intracavitarybrachytherapy.
Materials: 2 phases of the investigation were performed:1. A theoretic studyof dose distribution from distinct applicators for treatment of tumors of different size.We compare various methods of anal cancer treatment using different implants for different target configurations. We calculated treatment
plans for various tumors using 3 different applicators:1. Proctostat with various shields.2. MUPIT applicator set.3. Miami Applicator Set.Comparison
was performed with the following parameters: Coverage index, External volume index, Relative Dose Homogeneity index, Overdose volume index. Also
we determined the dose at 12 reference points - six of them were at 2 mmfrom the applicator and defined maximum observed dose in the rectum, andthe other six were at a distance of 5 mm from the tumor and these defined thedose decrease over the tumor. The reference points have clinical significance,
but we do not have complete control over the tumor dose and the overdoseof normal tissues; therefore we introduced dose-volume parameters.Criteria
for evaluating treatment plans were determined. The main parameter should
be determined in accordance with the task.The Miami Applicator Set is goodfor intracavitary brachytherapy, but if you want to control the overdose of the1083 poster
PARAMETERS AFFECTING THE UNKNOWN RECTUM DOSE IN
HDR BRACHYTHERAPY OF PROSTATE CANCER WHEN USING APROSTATE DISPLACEMENT KIT
B. Bø1 , C. Leite2 , E. Kofoed-Larsen2 , K. Hammerfjell Hagen2 , Folkedal2 ,E. S. Bergstrand1
1
DNR - N ORWEGIAN R ADIUM H OSPITAL, Oslo, Norway
2
O SLO UNIVERSITY COLLEGE, oslo, Norway
Purpose: HDR brachytherapy of prostate cancer (intermediate to high risk)
is used as a boost (10 Gy x 2) before external radiotherapy (50 Gy) at OUS
Radiumhospitalet. Rectum is an organ at risk to which the dose should be reduced to the greatest extent possible. HDR brachytherapy gives high dose to
the prostate gland, without affecting the surrounding tissue to a great extent.
This is favourable when the dose tolerance to organs at risk should not be
exceeded. A prostate displacement kit, which is an inflatable water balloon
surrounding the rectal ultrasound probe, is used to increase the distance between the rectum and prostate in HDR brachytherapy. In the planning phase

S 403(live plan) the water balloon is distended, but during radiation treatment (postplan) it is deflated. The water balloon improves image quality, which is important for proper placement of HDR needles in the prostate gland. When aballoon is used a reduction in rectal dose is expected when the water is removed, because the distance between the rectum and prostate gland should
increase. In this study the postplan images, without the water in the water balloon, were used to calculate the rectum dose. The purpose was to investigate
whether one can use parameters in the live plan to make a quick estimate ofthe dose to rectum when the water balloon is deflated.
Materials: Data from 8 patients who have completed two HDR brachy treatments was included in the study. Each treatment plan has a set of live andpost plan images. In live plan the delineation of the structures is performed.
The delineations were exported from live plan to post plan which causes a
mismatch between the structures and the delineations because the balloon
is deflated in the post plan. Therefore the delineation of the rectum and needles had to be adjusted in post plan in order to obtain the rectum dose after
emptying the water balloon. In hope of finding a model for estimating the post
plan (no-water) rectal dose while avoiding the time-consuming process justdescribed above, dose reduction to 2cc was plotted as a function of balloon
thickness, the size of the PTV and the number of needles. The average dose
reduction was also calculated.
Results: Our work s showed that reduction in rectal dose associated with theremoval of water was influenced by the number and placement of needles,
the size of the PTV and the balloon thickness. The latter seemed to havethe greatest correlation with dose reduction. Plotting dose reduction as afunction to the balloon thickness gives the function y = 0,3847x 0,7743 andan R2 0,4013.
Conclusions: The balloon thickness was found as the most reliable functional parameter for estimating the dose reduction to the rectum. However,this can not be used as a clinical guidance without further review due to therather low correlation. This may be related to the size of the data included inthis study and that other factors not quantified affect the relationship between
rectum dose with and without water in the water balloon.
1084 poster
RADIOBIOLOGICALLY EVALUATED DWELL TIME MODULATION RESTRICTION IN HIPO OPTIMIZED HDR PROSTATE
BRACHYTHERAPY IMPLANTS
P. Mavroidis1 , Z. Katsilieri2 , V. Kefala2 , N. Milickovic2 , N. Papanikolaou3 , A.
Karabis4 , N. Zamboglou5 , D. Baltas26
1
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Department ofMedical Radiation Physics, Stockholm, Sweden
2
K LINIKUM O FFENBACH G MB H, Department of Medical Physics Engineering, Offenbach am Main, Germany
3
U NIVERSITY OF T EXAS H EALTH S CIENCES C ENTER, Department ofRadiological Sciences, San Antonio, Texas, USA
4
PI M EDICAL LTD., Ampelikipoi, Athens, Greece
5
K LINIKUM O FFENBACH G MB H, Offenbach am Main, Germany
6
U NIVERSITY OF ATHENS, Department of Physics, Nuclear and Particle
Physics Section , Athens, Greece
Purpose: The selective existence of high dose volumes around some few
dominating dwell positions is one of the issues that have to be accounted forin HDR brachytherapy planning, especially if there is no information available
about its necessity. The limitation of the free dwell time modulation can eliminate this effect. This possibility can be offered by HIPO, which is an inverse
treatment plan optimization algorithm. Although in treatment plan optimization there are various methods that try to regularize the variation of dose
non-uniformity in order to find a good dose distribution they do not provide
any information regarding the expected treatment outcome.
Materials: The dose distributions of 12 clinical HDR brachytherapy implants
for prostate that were produced by HIPO with modulation restriction (MR)have been compared with alternative plans by HIPO without MR. The clinicaleffectiveness of the different dose distributions was investigated by examining all common dose-volume indices for the prostate and the organs at risk
(OARs) (the individual dose volume histograms are shown in the figure below)
and calculating their corresponding response probabilities using the Poissonand the relative seriality models. Furthermore, the complication-free tumor
control probability, P+ and the biologically effective uniform dose were used
for treatment plan evaluation and comparison.
Results: Based on the clinically used dosimetric indices, HIPO with a MR of
0.1-0.2 can produce high quality treatment plans which are practically equivalent to those that are produced by HIPO without MR. However, some of theradiobiological indices showed a considerable variation between the different
plans. Compared to the HIPO without MR treatment plans, the HIPO with
MR plans demonstrated a lower total dwell time by a mean of 1.4% that wasproved to be statistically significant (p=0.002). Furthermore, the HIPO with
MR plans produced a higher P+ by 0.5%, which stemmed from a better sparing of the OARs by 1.0%.

S 404B RACHYTHERAPY: V ERIFICATION AND DOSIMETRYB RACHYTHERAPY: V ERIFICATION AND DOSIMETRY

Conclusions: Statistically significant correlation was found between degreeof edema of prostate followed by CT-guided interstitial brachytherapy using
125
I microsources and number and total activity of seeds. No statistically significant dependency was found between degree of edema and age of patient,level of PSA, and average activity of seeds. One can suggest the dependency might be detected as a result of multi-variant analysis. In addition tothese factors another factors should be included in the study. New conclusions also will be published.
Conclusions: The present analysis shows that the HIPO with MR treatment
plan optimization gives on average similar results with the HIPO optimization
without MR regarding common dosimetric indices and widely known radiobiological measures. Based on our results, it appears that a minor improvementin the effectiveness of the optimized HDR dose distributions is expected to be
introduced by the examined dwell time regularization technique.
1085 poster
THE ANALYSIS OF SIGNIFICANT FACTORS OF DEVELOPMENT
OF EDEMA DURING PERMANENT BRACHYTHERAPY WITH
MICROSOURCES 125I
N. Panarina1
1
C LINIC OF F EDERAL M EDICAL B IOLOGICAL AGENCY OF RF, Centre of
Brachytherapy of Prostate Cancer, Obninsk, Russian Federation
Purpose: While performing CT-guided brachytherapy of prostate cancer using the permanent implantation of microsources 125 I the edema is unavoidable. Its level is variable from case to case. In search of the answer to aquestion on influence of the certain factors on the level of edema we havecarried out the statistical analysis the results of treatment of 500 patients of
the Centre of Brachytherapy of prostate cancer, headed by Dr. Pavel Sviridov,
Obninsk, Russia. In this article are preliminary conclusions. Purpose: To findfactors that have the most influence on development of edema during permanent brachytherapy with microsources 125 I. The knowledge of the reasons ofdevelopment of edema will allow to raise degree of covering prostate 100 %treatment dose (V100) one of the basic criteria of quality BT, to lower risk ofdevelopment of postoperative complications and to keep quality of life of thepatient.
Materials: Ninety-four patients treated with 125 I under CT-guided permanent
prostate brachytherapy were evaluated. Volume of prostate before and immediately after BT was assessed using CT-images by the same radiologist.
The edema factor (K) has been calculated in absolute values as: K = V2 V1,
where V1 volume of prostate before BT, V2 volume of prostate after BT. For
the statistical analysis following factors have been chosen: age of patients at
the moment of BT; the level of PSA; number of seeds; total activity of seeds,
average activity. For implantation under CT-control are used the different activities in a range 0,25 - 0,55 mCi. Volume of prostate before BT ranged from
14 to 79 sm (mean 32), after implantation it ranged from 20 to 150 sm (mean47). The edema factor ranged from 1 to 86 (mean 15). The Spearman nonparametric correlation analysis has been applied to studying of interrelationof degree of edema of prostate with investigated factors. During this analysis
the null statistical hypothesis about absence of communication of signs which
deviated at p <0,05 has been checked up.
Results: Results of the Spearman nonparametric analysis are presented inTable 1.

1086 poster
THE EFFECT OF RIB AND LUNG INHOMOGENEITY ON THE
DOSE DELIVERY TO LUNG AS A RESULT OF IR-192 HDR BREAST
BRACHYTHERAPY: A MONTE CARLO STUDY
H. Salehi Yazdi1 , R. Jaberi2 , H. shabani3 , S. A. Vaezzadeh3
1
A MIRKABIR U NIVERSITY OF T ECHNOLOGY, Tehran, Iran Islamic Republicof2
C ANCER I NSTITUTE T EHRAN U NIV. OF M EDICAL S CIENCE, Tehran, Iran
Islamic Republic of3
T EHRAN U NIVERSITY OF M EDICAL S CIENCE, Department of Medical
Physics and Engineering, Tehran, Iran Islamic Republic ofPurpose: This study investigates to what extent the dose response received
by lung for a commercially available treatment planning system 192 Ir highdose-rate (HDR) in breast brachytherapy is accurate, with the emphasis on
tissue inhomogeneities and taking into account the presence of ribs in dosedelivery to lung.
Materials: CT image scan of breast aids to construct a patient-equivalentphantom as used in the clinical treatment planning system. An implant involving of 13 plastic catheters and 383 programmed source dwell positions
were simulated, Using MCNPX code.
Results: Results are compared with corresponding commercial TPS in theform of percentage isodose and cumulative dose volume histogram in breast,
lung and rib. The comparison of Monte Carlo results and TPS calculationshows that the percentage isodose greater than 75% in the breast which arelocated rather close to implant or away from breast curvature surface andlung boundary are in well agreement.TPS calculations however overestimate
dose in lung for lower isodose contours that are lying near the breast surface
and boundary of breast and lung and are relatively away from the implant
Conclusions: Taking in to account the rib and entering the actual data forbreast, rib and lung, revealed an average over estimation of dose by a factor
of 8% in lung for TPS calculation. Therefore the accuracy of the TPS results
may be limited to regions near implants where the treatment is planned andis more conservative approach to regions at boundaries with curvatures ortissues with different material than breast.

Brachytherapy:
dosimetry

Verification and1087 poster
A VIRTUAL PHANTOM/DICOM PROTOCOL - BASED QA PROCEDURE FOR CONTEMPORARY HDR 192IR BRACHYTHERAPY TPS
K. Zourari1 , E. Pantelis1 , A. Moutsatsos1 , E. Roussou1 , E. Georgiou1 , L.
Sakelliou2 , P. Karaiskos3 , P. Papagiannis1
1
M EDICAL S CHOOL , U NIVERSITY OF ATHENS, Medical Physics Laboratory,
Athens, Greece
2
U NIVERSITY OF ATHENS, Nuclear Particle Physics Section, Athens,
Greece3
U NIVERSITY OF ATHENS, Medical Physics Laboratory, Athens, Greece

Purpose: Contemporary brachytherapy TPS employing advanced dose calculation algorithms have begun phasing in to clinical practice. This marks asignificant departure from the simplified assumptions of conventional TG-43
based TPS dosimetry. New methods are therefore required to affirm the dosimetric accuracy improvement of these TPS. These methods should be readily
available and suitable for use in the clinic in order to meet regulatory demands
for commissioning and enhance uniform transition from conventional to contemporary planning practice.
Materials: A set of virtual phantoms were prepared in DICOM CT image format. Four phantoms comprised homogeneous water geometries appropriate
for checking automatic catheter reconstruction, source dosimetry accuracy
in TG-43 conditions, altered scatter conditions and the presence of shielded
applicators. Two more phantoms were prepared to assess TPS accuracy ininhomogeneous geometries, as well as the efficiency of auto-contouring, volumetric and DVH calculation TPS features. These were imported to the Oncentra v3.3 and Brachyvision v10.0 TPS. TG-43 results from both TPS andresults obtained using the Acuros grid based Boltzmann solver of the latter
TPS were exported in DICOM-RT format. Reference dose distributions wereobtained using MC simulations for the VS2000 and microSelectron-v2 HDR
192
Ir sources. MC and TPS comparison results were performed using custom
made tools where necessary.
Results: MC and TPS comparison results in homogeneous phantoms
yielded very good agreement for both TPS with noticeable differences observed at a limited number of points. Although these differences are of minor
clinical significance, they could easily go undetected when using conventional
tools that perform comparison at user selected points. Both treatment planning systems were found to perform satisfactorily in terms of catheter reconstruction, contouring and DVH calculations. Comparisons also confirmed theability of the Brachyvision TPS to accurately account for scatter conditions,applicator and patient inhomogeneities. Differences beyond the acceptancecriteria, which were set equal to the statistical uncertainty of MC, were spatially limited in agreement with similar findings in the literature.
Conclusions: The tools and procedure proposed in this work are shown
appropriate for a thorough QA test of dosimetric performance and other basic
features of both conventional and contemporary brachytherapy TPS.
1088 poster
CALIBRATION AND USE OF GAFCHROMIC® EBT2 FILMS FOR QA
IN HDR BRACHYTHERAPY
E. Meilán Bermejo1 , F. Del Moral1 , L. Pereira1 , A. G. Teijeiro Garcia2 ,A. Lopez Medina1 , V. M. Munoz Garzon2 , M. Salgado Fernandez2 , B.
Andrade1 , D. Medal Francesch1 , J. S. Vázquez Rodríguez1 , S. Francisco1
1
H OSPITAL DO M EIXOEIRO, Medical Physics, Vigo (Pontevedra), Spain
2
MEDTEC, Vigo (Pontevedra), Spain
Purpose: One of the challenges of dosimetry is the surface-dose determination, because its experimental complexity. Gafchromic EBT2 films haveexcellent properties like a high spatial resolution or a precise dose response
at a wide energy range with low energy dependence. It allows their use inmany applications within radiotherapy. These two characteristics make themespecially suitable for skin dose measurements. Intrinsic brachytherapy problems are TPS limitations, applicator positioning errors (though Microselectron®from Nucletron has an accuracy of 1 mm, the positioning of the applicator or the mold in skin by a person introduces more uncertainty) or the transition applicator-skin. These additional problems can be solved, or at least
detected, with EBT2 films. The aim of this work is to calibrate Gafchromic
EBT2 films for its use in brachytherapy, show the problems of this calibrationand how these have been solved in order to obtain a relationship between
dose and pixel value. In our institution more than 258 treatments have beendelivered last 2010, 18 of them were skin cancer treatments. The main application of this study will be to check the correct dose delivery in these skincancer treatments.
Materials: Microselectron®192 Ir HDR (Nucletron) is one of the most usedsystems in brachytherapy. Its source has been widely simulated andcharacterized. Data published by Daskalov is the most referenced source
about this topic. These data have been used to obtain a relationship between
dose and dwell time using the air kerma strength of our source. A 6F
catheter (a plastic catheter with an external circumference of 6mm) was
fixed in a Gammex solid water block. A set of calibration measurements
has been made between 0.3 Gy and 8 Gy. Dwell time was calculated foreach calibration point using previously calculated relationship. The depth
calibration was chosen to 2 cm in order to obtain a reasonable ratio between
short delivery time and misalignment or positioning errors due a close
distance between film and source. The calibration dose is calculated 2
cm depth transversally to the stop point of the source. It means that thecalibration films will not be irradiated homogenous and it will be have to betaken in account. 24 hours after the irradiation, films were scanned fivetimes and averaged with a specific software on red channel to reduce noise.
Non-uniformity of the scanner has been taken in account and corrected bysoftware. Processed scanned film was analyzed with a home-made code
on Mathematica. Since the film had not been irradiated homogeneously, theaim was to obtain the pixel value in the closer position to the stop point of
the source (maximum pixel value). A least squares fitting to the function:f(x,y)=A1+A2x+A3y+A4x2 +A5y2 +A6x3 +A7y3 +A8xy+A9xy2 +A10x2 y+A11x2 y2

S 405

reduces the statistical noise associate to film and scanner.

Results: With the experimental configuration showed and subsequent analysis, a relationship between dose and pixel value was obtained. A graph
was constructed using Origin (OriginLab) and the result can be seen in attached figure. Obtained data were fitted to the equation D = B1 log(PV) + B2
[log(PV)]B 3+B4 being PV the pixel value in Omnipro I’mRT format.
Conclusions: This method allows a good fit of EBT2-film calibration forbrachytherapy QA purposes. Pixel values in film have been taken in accountthrought a least-squares fit to obtain a relationship between dose and pixel
value which makes possible to determine the calibration. This is a suitable
method for QA purposes in brachytherapy treatments.This research was supported by Consellere Econom Industria of Xunta de Galicia (Spain), underGrant 09SIN007CT.
1089 poster
EVALUATION OF ELONGATED AND CURVED 192IR AND 103PD
SOURCES USING A HYBRID TG-43 DOSIMETRY DOSE CALCULATION METHOD
E. Bannon1 , Y. Yang1 , M. Rivard1
1
T UFTS M EDICAL C ENTER, Radiation Oncology, Boston, USA
Purpose: Current brachytherapy dose calculations evaluate dose distributions of single sources and combine them to obtain the total dose. However,the superposition principle cannot account for source:source attenuation forextended brachytherapy sources such as elongated and curved sources. The
purpose of this study is to determine the optimal line segment length forcurved 192Ir and 103Pd sources by comparing the dose distributions of asingle source with source constructed with small line segments via different
techniques.
Materials: Monte Carlo (MC) simulations were performed in spherical liquidwater using MCNP5 for 192 Ir and 103 Pd. The *F4 mesh tally was used forline segments and toriodal ring sources. Voxel resolution of 0.5 mm and 2 x
109 photon histories resulted in 0.1% (k=1) statistical uncertainties 1 cm fromthe source. The superposition principle was first checked by comparing MCsimulated single sources to sources constructed with MC-simulated line segments for the same total length. Dose distributions for 0.1 cm to 8.0 cm line
segments were entered into the Pinnacle treatment planning system (TPS)
for source commissioning. Line sources of 0.1 cm to 8.0 cm and toroidal
sources of 0.5 cm to 8.0 cm diameter were constructed in TPS with different
line segment lengths. These dose distributions were then compared to theoriginal MC results using the IBA Dosimetry OmniPro gamma-index comparison with distance to agreement ∆d of 2 mm and dose difference ∆D criteria
of 2%, 5%, and 10%.
Results: For the MC superposition check, the average ratio was 1.009 for192
Ir and 1.051 for 103 Pd through the whole volume. With ∆d = 2 mm and∆D = 2%, 99.2% and 98.9% pixels passed the gamma-index comparison for192
Ir with 3.0 cm and 5.0 cm length, and 98.3% and 96.5% for 103 Pd for thesame lengths. Line segments < 1.0 cm produced the best comparison results; 1.0 cm was subsequently used for convenience. The region where the
gamma-index comparison failed was inside the source and within 0.25 cm of
the source periphery. Excluding this region, both 192 Ir and 103 Pd had passing
rates > 98% for tori radii < 4.0 cm. For 8.0 cm radii tori, the passing rate was >98% for 192 Ir with line segments < 2.0 cm. For 103 Pd, the passing rate was <98% for 8.0 cm tori for all line segment lengths due to self attenuation (figure).
However, the passing rate was > 99% for 8 cm 103 Pd tori with ∆d = 2 mmand ∆D = 5%. To achieve a passing rate > 98%, the ratio of line segment
length to the diameter of the torus should be < 0.25.

S 406

D OSE MEASUREMENT : APPLIED (1D/2D)

D ISEASE SPECIFIC ISSUES
a need to use an uniform protocol in order to be able to compare the parameters used in different studies. The general use of the ESTRO/EAU/EORTC
recommendations could solve this problem.

erative chemo-radiotherapy is nowadays the standard treatment. Our study,in spite of a small number of pts included, showed that R0 resections andnodal ratio are stronger predictors of survival.

1091 poster
QUALITY ASSURANCE OF BRACHYTHERAPY TREATMENT PLANNING SYSTEM FOR I-125 EYE PLAQUE DOSIMETRY
S. Deshpande1 , R. Kumar2 , P. Patwe1 , R. Mhatre1 , V. Anand1
1
P.D. H INDUJA N ATIONAL H OSPITAL, Department of Radiation Oncology,
Mumbai, India
2
B HABHA AUTOMIC R ESEARCH C ENTRE, RPAD, Mumbai, India

Conclusions: A conventional brachytherapy TPS and a new brachytherapy
dose distribution comparison technique were used to evaluate the superposition principle for elongated and curved 192 Ir and 103 Pd brachytherapy sources.
The optimal line-segment lengths for wire and toroidal sources were determined by comparing dose distributions based on MC methods and the TPS.
1090 poster
INTERPRETATION OF DOSIMETRIC PARAMETERS FOR PERMANENT PROSTATE BRACHYTHERAPY: IMPORTANCE OF THE
ESTRO/EAU/EORTC RECOMMENDATIONS
E. Verhenne1 , K. Stellamans1 , A. Lambrecht1
1
A.Z. G ROENINGE C AMPUS L OOFSTRAAT, Department of Radiotherapy,
Kortrijk, Belgium
Purpose: In our center, we use real-time intra-operative dosimetry with ultrasound verification of seed positioning for permanent prostate brachytherapy.
In this study we compared the variation in dosimetric outcome for the different dosimetric parameters between our approach and the recommendationsof ESTRO/EAU/EORTC regarding implant and post-implant dosimetry.
Materials: During implantation procedure we take 5mm steps ultrasound images and we outline the prostate as the visible contour without any expansion. The prescribed dose is 145Gy to the 100%-isodoseline which encompass the prostate on most places by one to a few millimeters in the different
directions except for the posterior border where the 100%-isodoseline follows this border. For post-implant evaluation, CT-images are taken 4 to 6
weeks after implantation and the prostate as such is outlined on the different
slices.For this study, a second clinical target volume (CTV) according the ESTRO/EAU/EORTC recommendations was outlined: prostate with an expansion of 3mm in each direction except for the anterior rectal wall and the bladder neck. For post-implant dosimetry we used two different CTV-delineations.
The CTV-P is the post-implant contour of the prostatic gland defined by thecapsule, where the CTV-PM is the CTV-P with a three-dimensional expansion of 3mm. We have included 70 patients in this study, being treated fromjanuary 2009 until august 2010, for which we have calculated the dosimetric parameters D90, V100 and V150 with the Variseedanning system for thedifferent CTV-delineations.
Results: First we evaluated the intra-operative implant dosimetry. If we add
the margin to the prostate we have an increase in volume for the CTV witha mean of 28.0% (SD= ±3.3%). The mean D90 for the prostate is 179.0Gy(SD= ±3.2Gy). For the CTV the D90 drops to a mean of 157.3Gy (SD =±7.4Gy). The V100 of the prostate has a mean of 98.7% (SD= ±0.6%)
which becomes for the CTV a mean of 94.0% (SD= ±2.3%). 45 of 70 patients(64.3%) didn’t meet the required V100 95%. The V150 for the prostate hasa mean of 64.6% (SD = ±4.6%) and for the CTV the mean is 55.4% (SD= ±4.0%).For the post-implant dosimetry we found the following results. By
adding the margin to the prostate we see an increased volume for the CTVPM with a mean of 51.0% (SD = ±8.1%). The mean D90 for the CTV-P is182.5Gy (SD ±15.5Gy) and for the CTV-PM mean D90 is 141.1Gy (SD =±12.4Gy). The requirement of D90 above 145Gy was not fulfilled for only
1 patient regarding the CTV-P definition but for the CTV-PM there are 45
patients (64.3%) who didn’t fulfill the requirement. For the CTV-P mean V100
is 97.6% (SD= ±1.9%), the mean of the CTV-PM is 87.9% (SD= ±5.1%).
The mean V150 of the CTV-P is 73.1% (SD= ±9.1%), the mean V150 of the
CTV-PM is 55.9% (SD= ±8.2%).
Conclusions: This study shows that the value of the dosimetric parameters
in one patient can vary a lot if different specifications of CTV are used. There’s

Purpose: Dosimetric verification tobrachytherapy treatment planning system(BTPS) (BrachyVision) for I-125 eye plaque dosimetry using Gafchromic film.
Materials: Bhabha Atomic Research Centre (BARC) developed Iodine (I125) Occu-Prosta source was configured in brachytherapy treatment planningsystem (BTPS) (Brachyvision; Varian Medical System, USA). Published dosimetric parameters as per AAPM TG43U1 of the source: dose rate constant,anisotropy functions, radial dose function and geometry function were used
for configuration of the BTPS. Gafchromic film (EBT film, ISP Inc USA) wasused to compare the dose calculated by treatment planning from single I-125
source at different depths. CT images of virtual water phantom sheets were
imported into the planning system for dose calculation. Similar set-up was repeated during experimental measurements. Depth dose curve due to a single
source was calculated by BTPS and measured using the Gafchromic films.
Dose at depth of 5 mm and 10 mm were calculated by BTPS for single source
and films at these spatial positions were irradiated for the corresponding calculated dose time. Eye plaque of 14 mm diameter with twelve I-125 seeds
source geometry was entered in treatment planning system. Gafchromic film
was placed at 5mm and 10mm from center of curvature of plaque for BTPS
calculated time. Irradiated EBT Gafchromic films were scanned with flatbed
scanner (Epson Expression 10000XL; EPSON, UK). The scanned images
were analyzed using the ImageJ software (NIH, USA).Gafchromic film wascalibrated with 6 MV x-ray photon beam from a medical linear accelerator
and proper energy correction factor was applied in estimating the dose fromthe I-125.
Results: Measured depth dose curveshows good agreement with BTPS calculated depth dose curve. Measured and calculated dose values by single
source at 5 mm and 10 mm were within acceptable limit. Calculated andmeasured doses at 5 mm and 10 mm for 14 mm eye plaque were in good
agreement.
Conclusions: BrachyVision treatment planning system calculated doseshows good agreement with measured values..

Disease specific issues
1092 poster
GASTRIC CANCER TREATMENT: THE EXPERIENCE OF
O. Santa Cruz1 , A. L. Vasconcelos1 , F. Pina1 , J. Cerveira2 , G. Marcelino2 ,I. Monteiro Grillo1
1
U NIVERSITY H OSPITAL S ANTA M ARIA, 1st Clinical Oncology Department,
Lisboa, Portugal
2
U NIVERSITY H OSPITAL S ANTA M ARIA, School Medicine, Lisboa, Portugal
Purpose: The aim of this analysis is to compare our results with the standard
treatment reference, and to analyse the correlation between the degree ofresection and survival
Materials: 61 patients (pts) with gastric cancer undergone surgery between
February 2003 and Febreuary 2010 followed by adjuvant QT/RT according
to the INT 0116 trial, and were included in this retrospective study. 56.2%
of pts underwent a total gastrectomy. Localization was proximal in 18.7%,
middle in 37.5% and distal in 43.7%. D1 dissection was performed in 75%
pts, with 50% tumor size less than 50mm; 31 (50%) pts had grade 3 tumors.
Splenectomy was performed in 10.8% of pts. Localization, type of resection,
linfadenectomy D1 or D2 and percentage of removed nodes vs positive nodes(nodal ratio) were analysed. Recurrence was classified according to locoregional (surgical bed and regional nodes), peritoneal and metastatic disease.
Results: The median follow-up was 30 months (95% CI=18-40mths). The
overall survival was 52.4% (32pts). Ten pts (16.4%) were lost for follow-up
and 19 pts died, (four with no evidence of disease). Median age was 62 years
and 62.3% of pts were males. The mean overall and specific survival was
16 mths (95% IC=8-31 mths) and 15mths (95% IC=7-31 mths) respectively.
Eleven pts (18%) had recurrence disease: 6 pts with peritoneal recurrence, 6
pts with metastatic disease and 1 pt with locorregional recurrence. Between
pts who are alive 54.8% (p=0.04) had a nodal ratio <20% and 81.2% of pts(p=0.03) had negative microscopic margins.
Conclusions: Gastric cancer is a very aggressive disease. Surgical resection remains the primary curative treatment option and combined with postop-

Dose measurement:(1D/2D)applied1093 poster
DOSIMETRIC PROPERTIES OF RADIOPHOTOLUMINESCENTGLASS DOSIMETER IN HIGH-ENERGY ELECTRON BEAMS
K. Son12 , H. Jung12 , S. H. Shin2 , H. H. Lee23 , M. S. Kim12 , Y. H. Ji12 , K.
B. Kim12
1
U NIVERSITY OF S CIENCE AND T ECHNOLOGY, Seoul, Korea Republic of
2
KOREA I NSTITUTE OF R ADIOLOGICAL AND M EDICAL S CIENCES, Seoul,
Korea Republic of
3
YONSEI U NIVERSITY, Seoul, Korea Republic ofPurpose: The purpose of this study was to investigate the suitability of GDbased dosimetric systems for high-energy electron beams for clinical use.
Therefore, we measured the dosimetric features of GD including dose linearity, reproducibility, angular dependence, dose rate dependence, and energy
dependence for electron beams applications at 10 different electron energy
beam qualities.
Materials: The GD system examined consists of silver-activated metaphosphate glass detectors and a fully automatic reader unit. The elemental composition of the GD used was; P: 31.55%, O: 51.16%, Na: 11.00%, Al: 6.12%,
and Ag: 0.17%. The model GD-302M used in this study had a diameter of
1.5 mm and a length (without its holder) of 12 mm. The reader unit (FGD1000, Asahi Techno Glass Corporation, Shizuoka, Japan) used detects theintensity of the orange luminescence. After exposure to UV stimulation, thestable RPL centers remains at the exposed level. The GD-302M was irradiated in a water phantom with therapeutic electron beams. We used nominal
electron energies of 5, 7, 8, 10, and 12 MeV from a Siemens Mevatron linear
accelerator and 6, 9, 12, 16, and 20 MeV from a Varian Clinac iX linear accelerator. Absorbed doses delivered to GDs were calculated from the ionizationchamber calibration factor using the absorbed dose to water in accord with
the IAEA Code of Practice TRS-398. Dose linearity of GDs was evaluatedby comparing delivered and absorbed doses. The delivered dose range wasfrom 1 to 10 Gy and GDs were irradiated at nominal energies of 6, 9, 12, 16,
and 20 MeV. GD reproducibility was measured using 100 GDs with electronenergies of 6, 9, 12, 16, and 20 MeV. GDs were set at reference depths (Zref(cm) = 0.6R50 - 0.1) in the water phantom for each electron beam energy.
Angular dependence was measured using a 9 MeV from the Varian Clinac
iX linear accelerator and the spherical PMMA phantom. Measurements weremade at angles of 0◦ , 15◦ , 30◦ , 45◦ , 60◦ , 75◦ , 90◦ , and 105◦ . Dose rates
dependence was measured using 9 MeV and a depth of dmax with 10x10
cm2 applicator size. GDs were irradiated to a 2 Gy at each of the following
dose rates: 100, 200, 300, 400, 500, 600, and 1000 MU/min. To determine
the energy dependence of GDs for electron beams, GDs were set at thereference depth in the water phantom and measurements were taken 100 timesin
the nominal energy range 5 to 20 MeV.
Results: For high-energy electron beams, the results of dose linearity measurement showed well fitted regression lines with R2 = 0.999 between 6 MeV
and 20 MeV.The reproducibility of the 100 GDs was ±1.2% (one standard
deviation). The angular dependence of the GD is normalized versus the
GD readout value at 90◦ . GD response differences to the electron beam
were within 2.0% for angles ranging from 45◦ to 90◦ . In dose rate dependence, measured values were normalized to the value obtained from 500
MU/min. The uncertainties were measured within ±1.5% except the value
from 100 MU/min. Dose rates of 100 MU/min was obtained within 3.0%. Theenergy dependence on average showed the same trend with a variation of
0.975±0.012% (one standard deviation) for the Mevatron and the Clinac iX.
Conclusions: As a result, GD shows that it can be potentially used as adetector for determining doses when a high-energy electron beam is used.
1094 poster
EVALUATION OF DISTORTION DISTRIBUTION INTRODUCED BY
FLAT BED SCANNERS TO DOSE DISTRIBUTIONS MEASURED
WITH RADIOCHROMIC FILMS
K. Chelminski1 , G. K˛edzierski2 , B. Ksiadz
˛ 2 , P. Lewandowski2 , J. Turska2 ,W. Bulski1
1
T HE M ARIA S KLODOWSKA -C URIE M EMORIAL C ANCER C ENTER, Department of Medical Physics, Warsaw, Poland
2
WARSAW U NIVERSITY OF T ECHNOLOGY, Faculty of Physics, Warsaw,
PolandPurpose: The purpose of the study was the evaluation and comparison of

S 407

distortions introduced by two flat bed scanners to dose distributions results
measured using radiochromic dosimetry films.
Materials: In the study two models of flat bed film digitisers were examined using uniformly exposed radiochromic dosimetry films. Epson Perfection
V750 Pro was designed for scanning transparent media of maximum size of
8.5 by 11.7 inches (A4 format). Epson Expression 10000XL photo scanner
was designed for large format transparent media of maximum size of 12.2 by
17.2 inches (A3 format). Both scanners produced RGB colour images with48 bit depth (16 bit per each colour channel). Uniformly exposed Gafchromic
EBT radiochromic dosimetry films of size 8.5 by 11 inches were used for evaluation of the distortions introduced by the scanners. Because the films are
sensitive to UV radiation they were exposed outdoor by sun light during asunny day. The films were exposed horizontally for 10, 19, 37 and 72 minutes
reaching optical density (OD) 0.35, 0.43, 0.61, and 0.81 respectively. Duringexposition the films became blue dye resulting in the highest absorption of
red light. The exposed films were digitised and the red colour channel data
were extracted and analysed in order to find the response profiles over theglass bed in two perpendicular directions.
Results: For Epson Expression 10000XL the measured profiles show that in
the direction perpendicular to direction of the light tube move the distortions
are growing symmetrically at the distance of 4 inches from the centre to theborder of the film reaching maximal 3% higher output. The level of distortionin this direction does not depend on the optical density of the exposed films.
In the direction of the light tube move the distortions close to the film borders
reach 10% lower output in respect to the centre. The effect depends on the
optical density and is higher for more exposed films.For Epson Perfection
V750 Pro scanner the profiles show that in the direction perpendicular to thedirection of the light tube move the distortions depend on the optical density ofthe exposed films and are growing symmetrically at the distance of 4 inchesfrom the centre reaching from 2% to 7% lower output at the border of theunexposed film and of the exposed one to 0.81 OD respectively. In the lighttube move direction the distortions are distributed uniformly along the film
reaching about 2%. The effect in this direction does not depend on the opticaldensity of the exposed film.
Conclusions: The obtained results confirm that the dose distributions measured using films are biased by the distortions introduced by the scanners.
The experiments show that for each model of the scanner the planar distribution of magnitude of the distortions has to be identified and the correction
function has to be applied over the surface of the scanner glass surface.
1095 poster
IN VIVO DOSIMETRY WITH RADIOCHROMIC FILMS IN INTRAOPERATIVE RADIATION THERAPY
S. Guariglia1 , G. Meliadò1 , M. G. Giri1 , N. Marciai2 , C. Cavedon1 , S.
Maluta2
1
A ZIENDA O SPEDALIERA U NIVERSITARIA I NTEGRATA, Department ofMedical Physics, Verona, Italy
2
A ZIENDA O SPEDALIERA U NIVERSITARIA I NTEGRATA, Department ofRadiation Oncology, Verona, Italy
Purpose: The purpose of this study is the evaluation of the dose distributiondelivered to the target volume during intraoperative radiation therapy (IORT)
for breast cancer.
Materials: Since May 2006, 226 patients have been treated with IORT for
breast cancer. IORT was performed by means of a dedicated linac (Mobetron,
IntraOp, California) provided with four electron energies (4, 6, 9, 12 MeV)
in a dedicated and shielded operating room. The dose prescription was 21
Gy at the point of maximum dose.During the first two years we performedin vivo dosimetry in 40 patients with micromosfet detectors (TN502-RDM,
Thomson & Nielsen), and we recently introduced measurements by meansof radiochromic films (Gafchromic MD55-V2, ISP inc.), performed so far inten patients. We put the film under the mammary gland that constitutes thetarget volume: this position allowed us to verify that the whole target volume
was included in the reference isodose curve.
Results: In general we found an important inhomogeneity of the dose distribution, consistent with a significant variability of the target thickness.For every
patient we analyzed the maximum, minimum and mean dose.Considering all
the patients we found a mean maximum dose of 21.4 Gy (with SD of 6%)
and a mean minimum dose of 16.2 Gy (with SD of 8%).We also found that: the maximum dose might exceed the prescription dose, possibly because of
the irradiation geometry;- the minimum dose might be lower than the required
80% prescription dose, which entails underdosage of the target volume thatmight be due to inaccurate measurement of the thickness;- the minimum dosemight be higher than the expected 80% prescription dose;- the mean dose foreach patient is satisfactorily similar to the expected value.
Conclusions: Radiochromic dosimetry presents many pros versus mosfet
dosimetry:- it provides 2D information and not just a point-like information;it offers simplicity of handling (a radiochromic film is simpler to position thana micromosfet, that we used to sew to the exposed tissues);- it doesn’t needcables, which means no need for sterile catheters and no electrometer tobe connected in a sterile environment.An obvious disadvantage is to have a
response after many hours from treatment (at least 24h in our protocol).In
vivo dosimetry is particularly important, especially in IORT radical treatments
because the whole dose is delivered in a single session. The use of ra-

S 408D OSE MEASUREMENT : APPLIED (3D/4D)

D OSE MEASUREMENT : APPLIED (3D/4D)

diochromic films implies only an observation of the outcome of the single
treatment and it’s not intended to take a level of action, however by looking
at general results this dosimetric verification might show the need to improve
the procedure.Up to now, our results show us that the measured dose is satisfactorily similar to the expected distribution.
1096 poster
NOVEL SPIRAL PHANTOM FOR VOLUMETRIC MODULATED ARC
THERAPY DELIVERY VERIFICATION
M. Tanooka1 , H. Inoue1 , H. Doi2 , Y. Takada2 , M. Fujiwara2 , K. Okuhata1 ,F. Ishimaru1 , T. Yamashita1 , T. Sakai1 , H. Nakagawa1 , M. Oda1 , K.
Yasumasa1 , K. Sakamoto1 , N. Kamikonya2 , S. Hirota3
1
T HE H OSPITAL OF H YOGO C OLLEGE OF M EDICINE, Clinical Radiology,
Nishinomiya, Japan
2
H YOGO C OLLEGE OF M EDICINE, Radiation Oncology , Nishinomiya, Japan
3
H YOGO C OLLEGE OF M EDICINE, Radiology, Nishinomiya, Japan
Purpose: Volumetric modulated arc therapy (VMAT) method is a very novel
treatment technique, but it is insufficient to make dose verification at only
one point, profile, or in a singleplane. Complete verification has to be volumetric including total coverage of the cross-section of the beam at all gantry
angles. Conventionally we employed films sandwiched between stacked multiple square blocks, where the films were oriented either parallel or perpendicular to the beam. We have proposed a method for verifying VMAT delivery
using a newly developed spiral phantom (R-TEC. Inc., Tokyo, Japan) withradiochromic films.
Materials: A spiral phantom was newly conceived and manufactured in which
an EBT2 Gafchromic film (ISP Corp., Wayne, NJ, USA) was placed alonga spiral wall in water. The calculated data were obtained by projecting thepatient plan data on the spiral phantom in the Monaco treatment planningsystem (MTPS). The measured data were obtained by irradiating the spiralphantom as per the treatment plan. The calculated and measured data wereconverted to a two-dimensional (2D) dose distribution with the DD-System(R-TEC. Inc., Tokyo, Japan). Comparison of these dose distributions were
performed using the gamma index analysis (with distance to agreement anddose discrepancy set to 3 mm and 3%, and a dose threshold of 50% of the
maximum dose on each analyzed plane) for a simple plan and six VMAT
plans using 10 MV photons. Furthermore, our method was compared withthe conventional method.

1097 poster
ANALYSIS OF THE RECENT VERSION OF EBT2 FILM FOR ITS USE
IN DOSIMETRY
F. Lliso1 , M. D. C. Pujades Claumarchirant1 , C. Camacho1 , V. Carmona1 , J.
Pérez-Calatayud1 2 , F. Ballester3
1
H OSPITAL U NIVERSITARIO L A F E, Radiation Therapy Department,
Valencia, Spain
2
ITIC, H OSPITAL C LÍNICA B ENIDORM, Radiation Therapy Department,
Benidorm, Spain
3
U NIVERSITY OF VALENCIA -IFIC, Valencia (Paterna), Spain
Purpose: Due to their characteristics, EBT films have been of great interest
in 2D dosimetry since their introduction in 2004. In 2009, the manufacturers discontinued EBT films replacing them by EBT2 in order to improve thefilm dosimetric accuracy. After having worked with EBT, we received the first
EBT2 films in April 2010 and at the preliminary examinations this batch was
found to be very heterogeneous and the same occurred with the following
batch. After the recent changes incorporated by the manufacturer to increase
the film homogeneity (September 2010), we received a third batch (December 2010).The properties of EBT films have been widely studied and even for
the EBT2 films there are already extensive studies. However, differences exist between the publications in some of the key parameters that influence theuncertainty in dosimetry: ROI size used to characterize the film; sensitometriccurve and background subtraction. There is not a unique protocol for uncertainty evaluation and requirements to use the EBT2 films in measurementswith high dose gradients.The purpose of this work has been to characterize
the recent batch of EBT2 films in order to subsequently use it in IMRT andbrachytherapy measurements.
Materials: EBT2 films of batches F03181001-A, A041510-01AA and
A09171002 have been used. In our protocol films are calibrated in a Co60 unit (Theratron Phoenix) with 19 dose points (0-800 cGy), fitting the curve
to a 4th degree polynomial. Films are digitized with an EPSON Expression
10000XL Photo flatbed scanner, before and 24 hours after irradiation to perform registration and to subtract the background. The films are positioned in
the middle of the scanner bed, scanned in transmission mode (100 dpi, 48
bits RGB colour, TIFF format) and analysed with DoseLab (Childress 2009)software using the red channel.At the moment of this work we have studied,using pixel values (PV), some of the EBT2 films parameters that had been
already reported (Richley et al. 2010) but might be influenced by the latest
changes: - Film homogeneity- Inter-sheet uniformity- PV variation with successive scans (80 scans; 0, 1, 2, 3, 5, 8 Gy)- Uniformity with scanner position(2.5 cm intervals up to 10 cm; 0.2, 1, 3, 8 Gy)
Results: The preliminary results of the characterization of the latest EBT2
films (batch No. A09171002) are presented. This batch shows a better uniformity than previous ones; inter-sheet PV differences are within 1%; a slightdecrease of the PV with successive scans is observed (maximum 0.5%); theinfluence of the scanner position increases with the dose level, (for 3 Gy lessthan 2% at 7.5 cm off-axis, reaching 5% for 8 Gy at 10 cm off-axis), being
these values compatible with the literature.
Conclusions: This latest EBT2 batch shows better uniformity than initialones, although further work is necessary to assess our global uncertainty.
Finally, in our opinion the manufacturer should still keep on improving one of
the main concerns: the homogeneity of the film.
1098 poster

Results: The spiral phantom was used to validate the dosimetric accuracyof the treatment plan. Comparison of the calculated and measured data
provided a visually qualitative assessment of the treatment to be delivered.
Comparison between calculated and measured dose distributions yielded anaverage pass rate using gamma index (3%, 3 mm) of 88.3% (max 91.2%,
min 84.7%), however, the pass rate was lower than that of the conventional
method.
Conclusions: EBT2 Gafcromic film’s dose response was known to be very
similar to that of ion chamber scanned in water through comparisons of depth
dose. Therefore, the film system may continue to be the most practical andcost effective, and also provide a better spatial resolution than other 2D arraysystems. Additionally, one can clearly see the value of the spiral phantom asa qualitative assessment tool for complex isodose distributions obtained frominverse planning algorithms. A novel spiral phantom provides a simple andcost-effective approach to sample 3D dose distributions delivered by VMAT.
Furthermore, the spiral phantom offers a completely innovative approach torotational delivery QA (Quality Assurance) superior to familiar 2D conventions.

Dose measurement:(3D/4D)appliedDYNAMIC MODELLING OF THE DOSE RESPONSE OF POLYMERGEL DOSIMETERS
S. Ceberg1 , M. Lepage2 , S. Bäck1 , H. Gustafsson3 , C. Ceberg4
1
S KÅNE U NIVERSITY H OSPITAL , M ALMÖ, Department of Radiation Physics,
Malmö, Sweden
2
C ENTRE D ’ IMAGERIE MOLÉCULAIRE DE S HERBROOKE , U NIVERSITÉ DES HERBROOKE, Département de médecine nucléaire et de radiobiologie,
Sherbrooke, Canada
3
ACT H EALTH, Department of Medical Physics, Canberra, Australia
4
L UND U NIVERSITY, Department of Medical Radiation Physics, Lund,
SwedenPurpose: Modern dynamic radiotherapy techniques such as breathing
adapted volumetric arc therapy has introduced both motion and interrupted
beam sequences into the picture, which poses new challenges to dosimetry.
The advantage of using high resolution gel dosimetry when verifying theseradiotherapy techniques, is that the dose can be obtained in the entire irradiated volume and that the response is independent of energy, field size, andthe direction of the incident radiation. However, recently published data showthat some polymer gel compositions have a dose rate- and fractionation- (sequential irradiation) dependency. Since this may introduce inaccuracies forapplications of gel dosimetry in dynamic radiotherapy further investigationsin this area are highly desirable. The aim of this study was to design a dynamic compartment model to evaluate the effects of dose rate and fractionation schemes on the resulting R2 values, which is the MR parameter used forthe estimating the absorbed dose.
Materials: A model based on the assumption that magnetization in the gel

dosimeter is exchanged rapidly between the different chemical species andwater was developed. In this model, the protons affecting the magnetic resonance signal and the R2-value of the gel were separated into mobile protons (i.e., water protons and monomer protons), gelatin protons and polymer
protons. Each proton pool was assigned a specific relaxation rate and theweighted sum of the contributions from each pool was calculated. Upon absorption of radiation, protons from the mobile pool are gradually transferredto the polymer pool (Figure 1). A set of differential equations describing thetransfer between the different compartments were solved using an in-house
written Matlab code, and the resulting distribution of protons in the different
compartments was then used to calculate a global R2 value, which was compared to the corresponding measured R2 value. Polymer gel dosimeters were
irradiated from 0 4 Gy using different fractionation schemes (the total dose
was given in 1 33 fractions) and to 2 Gy with different dose rates (2.0 and 5.0
Gy/min).

S 409

tron primary beam, a whole process of commissioning was performed, including depth and profile dose and in-room fast neutron fluence measurements.
Results: The results obtained are quite satisfactory: the photoneutron spectra at superficial points show both fast and thermal component whereas atdeeper points the fast components becomes much less important. Furthermore, the magnitudes of the calculated thermal neutron fluence values in thephantom are in good agreement with those measured by the CIEMAT laboratory using TLDs.
Conclusions: The simulations provide realistic values of the neutron fluenceenergy spectrum at 16 points of an anthropomorphic phantom, which can beused to infer the equivalent neutron dose at these points from experimental
neutron fluence measurements. These fluence values can in turn be related
to in-room thermal neutron fluence measurements, thus providing us with auniversal method for patient neutron dose estimation.
1100 poster
MODELLING, VALIDATION AND PLANNING WITH XIO® FOR TOTAL
BODY IRRADIATION AT EXTENDED SSD (400 CM)
A. G. Teijeiro Garcia1 , L. Pereira2 , F. Del Moral2 , J. Vazquez2 , A. Lopez
Medina2 , D. Medal2 , F. Salvador2 , B. Andrade Alvarez2 , M. Salgado
Fernandez2 , V. Muñoz2
1
H OSPITAL DO M EIXOEIRO, Department of Medical Physics and Radiation
Safety, Vigo (Pontevedra), Spain
2
H OSPITAL DO M EIXOEIRO, Vigo (Pontevedra), Spain

Results: The compartment model captures the dose rate and fractionationdependence of polymer gel dosimeters. The difference between calculated
and measured R2-values was on average 1.1±1.6% (1 SD).
Conclusions: A simple compartment model was designed and can be used
to predict the gel dosimeter response both to fractionated irradiation and dose
rate variations for polymer gel dosimeters. By studying the basic dose response characteristics theoretically the understanding of the dose rate- andfractionation- dependency of the gel dosimeter has improved. Using thismodel the optimal gel dosimeter can be selected for each specific measurement.
1099 poster
HIGH MEGAVOLTAGE RADIOTHERAPY NEUTRON SPECTRASIMULATION INSIDE AN ANTHROPOMORPHIC PHANTOM
X. L. González Soto1 , K. Amgarou2 , J. I. Lagares3 , J. Muñiz3 , R. Méndez3 ,M. R. Expósito4 , F. Gomez1 , C. Domingo2 , F. Sanchez-Doblado45
1
U NIVERSIDADE DE S ANTIAGO DE C OMPOSTELA, Física de Partículas,
Santiago de Compostela, Spain
2
U NIVERSIDAD AUTÓNOMA B ARCELONA, Física, Barcelona, Spain
3
CIEMAT, Madrid, Spain
4
U NIVERSIDAD DE S EVILLA, Fisiología Médica y Biofísica, Seville, Spain
5
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Sevilla, Spain
Purpose: The evolution of radiotherapy has had the outcome of a better
confinement of the radiation dose around the clinical target. It seems now
necessary to develop additional methods to provide an adequate radiation
protection of the patient leading to an optimal treatment evaluation, accounting also the out-of-field dose delivered. In particular, neutron contaminationfrom high energy photon beams is still a subject of research and discussion.
The NEUTOR project aims to provide a universal means to estimate the patient neutron dose, using an anthropomorphic phantom. The responses of thedetectors and the relative biological effectiveness have a strong dependence
on the neutron energy. For this purpose, a set of simulations were performed
in order to calculate the neutron fluence spectra in 16 representative points
inside the NORMA phantom for a complete radiotherapy treatment.
Materials: Simulations were carried out using the MCNPX-2.6.0 code. The
calculation of the neutron spectra for each beam incidence was made in one
only simulation file, including the treatment room, the phantom and the linac.
In order to obtain a most realistic photoneutron spectrum of the Siemens
PRIMUS accelerator, the most up-to-date accurate geometry and material
composition, taken from Siemens datasheets, was utilized. Furthermore, as
neutron photoproduction depends heavily on the nominal energy of the elec-

Purpose: Total body irradiation (TBI) is a treatment in which patient is irradiated at extended SSD (350-400 cm). Dose is prescribed usually at the
midpoint of the abdomen. Most TPSs do not allow the treatment of patientswith SSD higher than 80-120 cm. On the other hand the use of a table TBI
with "spoiler" to increase the skin dose must be taken into account. Therefore, the use of a TPS for TBI involves measures and validation "ad hoc" forthis type of treatment.
Materials: The objective has been modeled a TPS (XIO®4.60.0 ) for clinical use in TBI treatments to evaluate the dose distribution. TPS calculations
have been done in Multi-Grid Superposition (MGS) method to improve dose
calculations at inhomogeneities like lungs. The linac is a PRIMUS (Siemens)
6MV. Spc have been measured at SSD=400 cm. Sc previously measured forconventional RT have been used. Additional PDDs at 130 cm with a simulated spoiler (1 cm PMMA at 5 cm of surface) have been measured. PDDs
at 400 cm and OARs have been measured and compare with TPS. In thesame sense we have used different phantoms with different size to simulated
abdomen, head and ankle. Gafchromics®films EBT2 and Alderson Rando
anthropomorphic phantom have been used to measure relative dose in an
inhomogeneous medium.
Results:

S 410D OSE MEASUREMENT : BASIC

D OSE MEASUREMENT : BASIC

Dose measurement: basic

films have a 97-µm thick protective polyester coating only on one side of the
7-µm thick active layer making them suitable for measurements of low energy electrons. The HD-810 films were calibrated in 100, 150, and 200 kV
x-ray beams using a PTW 30013 chamber and doses ranging from 0.5 to 70
Gy. Prior the actual dose enhancement measurements, (1x1) cm2 films were
soaked in iodine solutions with 0, 40, 80, 160 and 320 mgI/mL for 10 minutes.
The films were then placed on a 10 cm thick solid water slab and covered witha 1 cm thick solid water slab for build-up. The films were irradiated to what
would be a 2 Gy dose with no iodine using 100, 150, and 200 kV beams.
The films were washed with water and dried out after irradiation, read out ina flatbed scanner and converted to absorbed dose using the corresponding
calibration curves.
Results: The calibration curves for the three voltages are shown in Fig 1a.
The film dose response decreases with decreasing photon beam energy. The
difference between 200 kV and 100 kV for optical density (OD) of 0.08 is 28%.
The difference between 200 and 150 kV for the same OD is 19 %. HD-810
films are highly energy dependent at low photon beam energies. The ratioof dose with iodine to the dose without iodine, the dose enhancement factor(DEF), is plotted as a function of iodine concentration and tube voltage in Fig
1b. As expected, based on the mean energies of the studied beams (53, 71,
and 86 keV for the 200, 150, and 100 kV beams, respectively) and the K-edgeof iodine (34 keV), the DEF decreases with decreasing tube voltage. The
maximum measured DEF of 10.6 for 320 mgI/mL is to the first approximation
only 50% of the actual macroscopic DEF. This is due to the fact that the doseenhancement from the polyester coated side could not be measured due tothe short range of photoelectrons.
Conclusions: A methodology for dose enhancement measurements with
HD-810 Gafchromic films has been developed and tested with iodine contrast agent. Additional measurements with tungsten and gold nanoparticles
will be taken.

1101 poster
COMPARISON OF SURFACE AND PERIPHERAL RADIOTHERAPYDOSES USING ENHANCED DYNAMIC AND PHYSICAL WEDGES
A. Lahooti1 , A. Takavar1 , H. A. Nedaei2
1
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Department of Medical
Physics and Biomedical Engineering, Tehran, Iran Islamic Republic of2
T EHRAN C ANCER I NSTITUTE, Tehran, Iran Islamic Republic of

In general at good agreement between measurements and TPS has beenachieved, in figure is possible to see the agreement on PDD between TPS
results and measurements using EBT2 films. The most discrepant point isaround the maximum at 1.5 cm depth, TPS is not able to correctly calculate the electron contamination produced by the spoiler and underestimatesdose in that area about 3%, at deeper points discrepancy is lower.OAR at
SSD=400 has been measure using a phantom with chamber at 10 cm depth.
Measurements have been done moving this phantom in a position tranverse
to beam. A good agreement has been achieved with an uncertainty lesser
than 2% in absolute dose. Absolute measurements have been done withdifferent phantoms in order to simulated abdomen, head and Ankle.

Purpose: The wedge fields are often used in various clinical situations to
obtain homogeneous dose distribution around target volume. Differences insurface and peripheral dose between Enhanced dynamic wedge and physicalwedges are important for choosing a wedge system for clinical application.
The aim of this study is to measure and compare surface and peripheral dosein Enhanced dynamic wedge and upper Physical wedge using Gafchromic
EBT film and Advanced Markus chamber.
Materials: Measurements were performed using 6 and 18 MV X-rays from
Linac. Following exposure parameters were applied: 100 cm SSD, 5*5 cm2 ,10*10 cm2 and 20*20 cm2 field sizes for 15◦ and 30◦ wedge angles and 5*5
cm2 , 10*10 cm2 and 15*15 cm2 for 60◦ wedge angle. A 2*2 cm2 film wasplaced at the center and four pieces outside field on the surface of the solid
water phantom and at the depth of maximum dose deposition. All measurements were carried out and repeated by Advanced Markus Plane-Parallel
chamber (PTW). Measurements of peripheral doses were performed for fieldsizes of 5*5 cm2 and 10*10 cm2 at the distance of 5cm and 10cm outside thefields. For field sizes of 15*15 cm2 and 20*20 cm2 , measurements were done
only at 5cm distance away from outside the fields. We used water-equivalent
RW3 slab phantoms (PTW) for all measurements.
Results: Surface doses on the central axis under dynamic wedge are morethan that of the physical wedge using the same exposure conditions. The
maximum surface dose produced by the dynamic wedge is 27±2cGy andby the physical wedge is 24.5±0.5cGy for 30 wedge in 20*20 cm2 field size.
Peripheral doses of dynamic and upper wedges are similar (PV<0.002). Surface and peripheral doses for 18MV beams are less than that for 6MV. The
percentage discrepancies between 18 and 6MV beams for 5*5 cm2 , 10*10
cm2 and 20*20 cm2 for 15◦ wedge angle are 53.01, 43.56 and 35.36 ,respectively, this discrepancy reduces by increment of wedge angle. Our results showed a direct relationship between the eld size and surface/peripheral
doses. GafChromic EBT lm provides precise measurements for surface dosein the high energy photons. Agreement between lm and plane-parallel chamber measurements was found to be within ±0.8% for doses in depth of maximum dose. There was 7% overestimate on the surface doses when compared with the plane-parallel chamber measurements for all eld sizes in photon beams of all energies.
Conclusions: The two wedge systems produce significantly different surface
and peripheral doses that should be considered when choosing a wedge system for clinical use. Dynamic wedge and Physical wedge systems deliver
peripheral doses similar to those of open fields.

1104 poster
INFLUENCE OF THE PHANTOM COMPOSITION ON PERIPHERAL
NEUTRON ORGAN EQUIVALENT DOSE EVALUATION
C. Domingo1 , K. Amgarou1 , M. J. Garcia-Fuste1 , R. Barquero2 , M. R.

Conclusions: Biodistribution of [201 Tl](III)-DTPA-HIgG demonstrated significant inflammated tissue uptake and low muscle and blood uptake, allowing
for imaging of inflammated tissues.

1102 poster
DETERMINATION OF HUMAN ABSORBED DOSE OF 201 TL(III)DTPA-HIGG BASED ON BIODISTRIBUTION DATA IN RATS
A. Khorrami moghaddam1
1
T EHRAN U NIVERSITY OF M EDICAL S CIENCE, Department of Medical
Physics, Tehran, Iran Islamic Republic ofUsing an Alderson Rando anthropomorphic phantom and EBT2 films dose
has been measured and compared dose in lung, zone in which TPS overestimates dose about 7%.Preliminary comparisons with in vivo dosimetry (MOSFETs) in patients have obtained a discrepancy lower than 2% in central doseabdomen with TPS. Discrepancies are bigger in head (6.9%) due probably a
misalignment of MOSFETS and intrafraction motion of the head.
Conclusions: XIO® is suitable method to calculated TBI combine with agood immobilization system to avoid dose uncertainties. This method allows
reduce the number of MOSFET replacing them by TPS calculations.
This research was supported by Consellere Econom Industria of Xunta de
Galicia (Spain), under Grant 09SIN007CT.

Purpose: We attempted to estimate the absorbed dose in normal organs
and inflammated tissue following i.v. administration of [201 Tl](III)-DTPA-HIgG
by using biodistribution data in inflammation-bearing rats.
Materials: The percentages of injected dose per gram of each organ were
calculated. The Medical Internal Radiation Dose (MIRD) formulation wasapplied to calculate the absorbed dose for various organs.
Ctissue (t) =[ A tissue(t)/M tissue]/ A total/100 Where Atissue(t) is the 201Tl
activity in the sample, Mtissue is the mass of the sample and Atotal is thetotal activity of 201Tl injected into the rat.
Results:

S 411

1103 poster
DOSE MEASUREMENTS IN DOSE-ENHANCED RADIATION THERAPY
E. Graves1 , M. Bazalova1 , G. Nelson2 , N. Ackerman2
1
S TANFORD C ANCER C ENTER, Stanford, USA
2
S TANFORD U NIVERSITY S CHOOL OF M EDICINE, Department of Radiation
Oncology, Stanford, USA
Purpose: To experimentally evaluate dose enhancement for iodine contrast
agent and tungsten and gold nanoparticles irradiated with three kilovoltage
photon beams using HD-810 Gafchromic films.
Materials: Measurements of dose in dose-enhanced radiation therapy(DERT) are challenging due to the short ranges (20-100 µm) of photoelectrons released by kilovoltage beams in high-Z materials. These electrons
typically do not reach the active volume of common dosimeters. In thisstudy, dose enhancement was measured with HD-810 Gafchromic films (ISP,
Wayne, NJ). Unlike the laminated EBT and EBT2 Gafchromic films, HD-810

Expósito3 , J. A. Terrón4 , X. L. González Soto5 , F. Gomez5 , F. SanchezDoblado34
1
U NIVERSITAT AUTÒNOMA DE B ARCELONA, Department of Physics,
Cerdanyola, Spain
2
H OSPITAL U NIVERSITARIO DE VALLADOLID, Valladolid, Spain
3
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Sevilla, Spain
4
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Sevilla, Spain
5
U NIVERSIDADE DE S ANTIAGO DE C OMPOSTELA, Santiago de Compostela,
Spain
Purpose: Peripheral dose in radiotherapy could represent an important issue in the decision of the treatment strategy. The NEUTOR project has thegoal of estimating peripheral doses from the readings of a new online digital neutron detector [1] placed inside the treatment room. Measurementswith passive dosemeters are performed at 16 places of an anthropomorphic
phantom (NORMA) to correlate organ equivalent doses with the electronic
device measurement [2]. The original NORMA phantom was built in polyethylene, which is almost tissue equivalent for electron and photon transport, andthe lungs were simulated by low density wood. Nevertheless, questions may
arise about the behaviour of neutrons in polyethylene due the lack of O and,specially, N, which has a relevant cross section for neutron interaction.
Materials: A complete abdominal treatment was delivered into four identical shape phantoms, made on different materials: i) the original polyethylene NORMA, ii) a Nylon phantom (with higher N content than tissue) with
air cavities to simulate lungs, iii) a polyethylene phantom with thousands ofsmall urea filled cavities (with N content equivalent to tissue), and iv) a phantom with wooden boxes filled with real mammalian tissues, organs, bloodor bones, using pork meat. CT scans of the phantoms and posterior photon
dose distribution by Pinacle treatment planning system were obtained. CR-39
detectors were employed in the 16 locations prepared inside each phantom,
which were processed and read in the standard way [3].
Results: Neutron fluence is calculated from the readings of the CR-39 detectors, using the adequate calibration coefficient. The quality factor weighted
kerma factors for each phantom material is then used to convert to (organ)
equivalent dose at each measurement location. Figure 1 shows these factors
for polyethylene and ICRU tissue [4]. Although the big differences in thesecoefficients, equivalent dose results for the different phantoms lie in the sameorder of magnitude

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D OSE MEASUREMENT : BASIC

D OSE MEASUREMENT : BASIC
1106 poster
MEASUREMENTS AND UNCERTAINTIES VALUES FOR DOSE
POLARIZATION AND RECOMBINATION CORRECTION FACTORS
L. Alejo Luque1 , R. Rodríguez Romero1 , P. Castro Tejero1 , J. M. Fandiño
Lareo2
H. U. P UERTA DE H IERRO M AJADAHONDA, Department of Medical Physics
and Radiation Safety, Majadahonda, Spain
2
C ENTRO O NCOLÓGICO DE G ALICIA, Department of Medical Physics andRadiation Safety, A Coruña, Spain
1

Conclusions: The original NORMA phantom is a good first approximation
for neutron organ dose assessment, although more precise results require
the usage of phantoms having composition closer to tissue.
Acknowledgements: The authors are indebted to the University Law (LOU)
contract between the University of Seville and the Andalusian Health Service (SAS) and especially to the Spanish Nuclear Security Council (CSN).
We want to give thanks to J. P. Cano (workshop physics faculty university of
Seville), Mariano A. (carpentry) and Alejandro (Matadero del Sur) for the construction and cession of the pork for the phantoms.
References:
1. F G et al. (2010), Phys. Med. Biol. 55 10251039.
2. F Shez-Doblado et al. (2009), WC 2009, IFMBE Proccedings 25/I,
Berlin: Springer, 259-261.
3. C. Domingo et al. (2009), Radiation Measurements, 44, 1073-1076
4. B.R.L. Siebert and H. Schuhmacher (1995), Radiat, Prot. Dosim., 58,
177-183.

Purpose: Measurements and uncertainties values for dose polarization andrecombination correction factors (kpol, ks) for different cylindrical and planeparallel ionization chambers are discussed. These values are obtained using
photons and electrons beams of various nominal energies generated by Varian Clinac 21EX linear accelerators and TomoTherapy Hi-Art II, in order tostudy the behavior of these uncertainties and factors, and analyze trends.
Materials: Applying IAEA TRS-398 protocol, kpol and ks values were obtained for different chambers and energies: four PTW 30013 Farmer in 6MV,
15MV and 18 MeV, two PTW 31010 Semiflex, two PTW 31016 PinPoint 3D
in 6MV and 15MV, two Exradin A1SL in 6MV, two Roos 34001 and a Markus
34045 in 6MeV, 9MeV, 12MeV, 15MeV and 18MeV electron beams. Except
Exradin chambers, whose factors were obtained in TomoTherapy Hi-Art II 6
MV beam, a Varian CLINAC 21EX linear accelerator was used. Since dose
calibrations are corrected by recombination effect but not polarity, kpol uncertainty had to be estimated considering its maximum values reported incalibration certificates. Type A and B uncertainties were calculated with a
K=2 coverage factor.
Results: No significant variations with energy were found for polarity correction values, excluding PinPoint 3D chambers (that increase with photon energy) and Markus (that decrease with electron energy), although their uncertainties are comparatively higher. Also, Markus chamber shows higher kpol
values and uncertainties than those obtained for Roos chambers (< 1,001).
Excluding Farmer and Semiflex chambers, saturation factor values have noenergy dependence. In 18 MeV, Farmer chambers values were greater than
1,007. Markus values were lower (< 1.003) than Roos chamber values (>1,007). Polarity uncertainties are subestimated due to kpol true value is unknown.

1105 poster
IS REFERENCE CHAMBER CALIBRATION IN MV PHOTON BEAMSNECESARRY FOR ABSOLUTE DOSE DETERMINATION?
A. Vestergaard1 , H. S. Rønde2 , M. Berg2 , L. H. Præstegaard1
1

A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
2
V EJLE H OSPITAL, Department of Medical Physics, Vejle, Denmark

Purpose: To compare the two methods of absolute dose determination suggested in IAEA Technical Reports Series No 398 (TRS 398): 1) Referencechamber calibration in MV photon beams and 2) Reference chamber calibration in 60 Co combined with correction for the radiation quality of the user
beam (kQ factor).
Materials: The investigation evaluates six cylindrical ionization chambers of
the type FC65-G (IBA Dosimetry, Schwarzenbruck, Germany) with calibration
factors measured in 60 Co. Three different radiation therapy beams: 6MV SRS(stereotactic radio surgery mode), 6MV and 15MV were used. The corresponding Tissue Phantom Ratios (TPR20,10) of the beams are 0.660, 0.667
and 0.761. In addition, one of the ionization chambers has been calibrated in
MV photon beams from 4 to 18 MV at the NPL (National Physics Laboratory,
Teddington, Middlesex, UK). Below this chamber is referred to as the reference chamber. All other chambers were cross calibrated with the referencechamber using a solid water phantom (Gammex 457, Gamma Med, North
Jackson, Ohio) with chamber inserts. During the cross calibration, the twochambers were interchanged and a mean of the two measurements is used
for the cross calibration. All charge measurements were corrected for recombination. The kQ factor for each chamber and beam quality was calculated on
the basis of the cross calibration. In addition, the mean kQ value for all chambers for each TPR20,10 was calculated and compared to the corresponding
kQ factor tabulated in TRS 398.
Results: The mean kQ factors are 0.988 (SD: 0.002), 0.988 (SD: 0.002) and
0.968 (SD: 0.002) for 6MV SRS, 6MV and 15MV beams, respectively. The
ratios of mean kQ factors relative to the values in TRS 398 are 0.992, 0.992
and 0.987 for the 6MV SRS, 6MV and 15MV beams, respectively.
Conclusions: The measured kQ factors are up to 1.3 % lower than the tabulated kQ factors in TRS 398. As a consequence absolute dose determination
measurement using 60 Co calibration and kQ factors from TRS398 is up to
1.3% too high. This corresponds to the delivery of a too low dose to thepatients.

Results: We got output factors in cGy/UM which depend on the diametersof the cones , bevel degrees, energy and SSD. We have separated different
dependences, using the following absorbed dose equation. For a cone andenergy given dose D:D(SSD)=UMFCONE FOBL FCONE,OBL(SSD)Where
Fcone is the cone output factor, and shows the diameter dependency. We set
the reference Fcone to a diameter of 6 cm, 0 degrees and SSD=100 cm.FOBL
is the obliquity factor, and shows the bevel degree dependence . We set thereference FOBL to 0 degrees. FCONE,OBL(SSD) is the function that takes
into account de SSD dependence (Note that is a function not a factor).Data
calculated by this formalism were compared with the measured data, and the
maximum deviation was bellow 4% (few cases). That is sufficient, taking intoacount the uncertainties for this technique.
Conclusions: This formulation is a quick and simple way for this purpose,and is easy to implement, for example through a worksheet. Furthermore weconclude this formalism have a sufficient reliability level for IORT.
1108 poster
RECOMBINATION FACTOR DEPENDENCY ON IONISATION CHAMBER AND DOSE PER PULSE
B. Geelen1 , E. Kok1 , M. de Langen1
1

R EINIER DE G RAAF G ROEP, Radiotherapy Department, Delft, Netherlands

Purpose: For proper electron dose measurement in water, an accurate determination of the ion recombination factor ks is essential. ks depends onchamber geometry, the collecting voltage and ion density. We determined ks
using the 2 voltage method of Boag1 as recommended in the IAEA report2 .
We found, especially for the Farmer chamber, discrepancies of up to 1,4 %between the measured values for ks and values mentioned in the literature.
This raised the question whether values for ks from literature can be usedgenerally. The aims of this work are to determine the origin of the discovered
discrepancy and the correct way to determine ion recombination factors.
Materials: We investigated the chambers listed in table 1 with a Dose 1
dosimeter (Scanditronix). ks was determined for energies 6, 9, 12, 16 and 20
MeV on a Varian Clinac 2100c/d. We re-measured ks using different voltage
combinations (for constant V1) and tested the linearity of the chambers.To
derive the theoretical value of ks, the dose per pulse, the electrode separation d and µ, a constant depending on the ion mobilities and recombination
rate of the gas in the chamber volume, must be known. The dose per pulse
value for the linac was obtained from Varian. The values of d and µ wereobtained from the chamber manufacturers, as there are chamber-to-chamber
variations within a given chamber type. The value for µ for a Farmer chamber
must not be calculated using cylindrical geometry, as this would underestimate the value.The recombination correction on a Varian linac should not bemeasured with ’dose servo on’, because then the exact dose per pulse cannot
be determined.
Results: All voltage combinations (same V1) yielded the same results. Nochange was found in chamber sensitivity with polarising voltage. For all electron energies, the dose per pulse for the Varian linac was 0,0926 cGy. Thisvalue is higher than for Elekta machines (0,016 0,037 cGy/pulse). Calculating ks using Boag’s formula showed good agreement with our measurements
for especially the farmer and Roos chambers. (Table 1)

Conclusions: An homogeneous behavior for each chamber type can be observed: similar factor and uncertainty values. It seems that a generic polarization and recombination factors can be achieved. Further studies are
required. Also, it should be notice that polarity uncertainties grow as ion
chamber volume decreases.

Purpose: Intraoperative radiotherapy (IORT) is a direct technique of electron
irradiation on surgical bed. UM calculation for IORT requires a fast answer,
and we need a quick and simple calculation method (we must manage a greatamount of data) and easy to implement. In this paper, we show a simple
parametric method to obtain UM for this technique.
Materials: A Primus Linac (Siemens), with several IORT cones whose diameters are 3, 4, 5 6, 7 , 8, 9 y 10 cm, and are beveled at 0, 15, 30 y 45, provided
by MCP Iberia. We set the Linac apertures to 13x13 field size. Definitions ofclinical and geometrical cone axes are referred in the literature. The Relative
measurements were performed using a semiconductor detector: PDD along
clinical and geometrical axis, y dose profile perpendicular to clinical axis at
90%, 100% and 50% dose (normalized at maximum clinical pdd). In order tocharacterize dose for each pair cone-bevel degree, a Markus (PTW) ionization chamber was used, at the depth of the geometrical axis maximum, andat source-surface distance (SSD) from 100 cm to 110 cm (we have assumed
that maximum depth does not depend on SSD).

FFF and dose rate 400UM/min. Percentage depth dose curves (PDDs) were
measured point to point, using two ionization chambers (PTW-30013 Farmer
Chamber and PTW- 31016 Pinpoint chamber) with a NE Ionex Electrometer
for a 10 cm x10 cm square field. Two methods have been used to obtain
the recombination correction: the two-voltage Boag technique and a multivoltage analysis. For the Farmer chamber, the measurements were takenwith only two potentials (100 and 300 V), and values given by Bruggmoser etal (2007) were used to calculate the multi-voltage correction. For the Pinpoint,seven different voltages, ranging from 50 to 350 V, were applied to measurein six representative depths, covering all the charge collection range of PDD.
As with the Farmer chamber, 100 and 300 V measures were used for thetwo-voltage method. The values of Ks of other depths were obtained by interpolation. The multi-voltage analysis was implemented with all the voltages,
and the Ks of intermediate values of charge were calculated through a linear
regression.
Results: The Farmer chamber gives us differences between the PDD corrected by two-voltage and multi-voltage methods of up to 0.96%. When absolute measurements want to be done (without normalization in the reference
depth) differences are smaller a maximum of 0.17%. These results can be
explained since maximum differences in absolute dose are near the maximum, and that values are used as a normalization values in PDD while atdeeper points differences are smaller. The representation of the correction
factor Ks vs the collected charge is presented in the figure.Opposite behavior
happens with the Pinpoint chamber. The differences in absolute dose moves
around 0.7%, while the relative differences in the PDD are much lower (lessthan 0.1%). The explanation is that the slopes of the correction of both methods are quite similar, but not the correction value itself.

Conclusions: In summary, in terms of recombination correction, our results
indicate that is preferred to measure the PDDs with the Pinpoint chamber.
However, in order to measure the absorbed dose in reference conditions,
it is preferred to measure with a Farmer type chamber. In both cases, thedifferences between using the two-voltage method or the multi-voltage will besmaller than 0.2%.
1110 poster

1107 poster
PARAMETRIC FORMULATION FOR IORT UM CALCULATION
E. Cabello Murillo1 , M. A. De la Casa de Julian1 , F. Clemente Gutierrez1 , J.
García Ruiz-Zorrilla1 , R. Díaz Fuentes1 , A. Ferrando Sanchez1 , J. Castro
Novais1
1
H OSPITAL U NIVERSITARIO 12 DE OCTUBRE, Madrid, Spain

S 413

Conclusions: The discrepancies found in our initial measurements appeared
to be due to using values of ks obtained from literature. Therefore we conclude that ks should not be taken from literature. In stead they must be calculated using explicit values for dose per pulse and for d and µ for the usedlinac and ionisation chamber respectively. These parameters must be obtained from the manufacturers.
1109 poster
STUDY OF THE RECOMBINATION CORRECTION IN PDD CURVESFOR FLATTERING FILTER FREE (FFF) BEAMS
D. Navarro Jimenez1 , J. Puxeu Vaqué1 , R. De Blas Pinol1 , M. C. Lizuain1 ,F. Pino1
1
I NSTITUT C ATALÀ D ’O NCOLOGIA, Department of Medical Physics andRadiation Safety, L’Hospitalet de Llobregat, Spain
Purpose: The objective was to evaluate the recombination correction magnitude (Ks) for FFF beams and to compare two distinct methods to do it. It’s
known that the correction is very small for conventional beams, but maybe
not for FFF beams, due to the greater dose per pulse.
Materials: Measurements have been performed on a Clinac TRUEBEAM(VARIAN) linear accelerator with a photon beam of nominal energy 10 MV

THE COMPONENT ANALYSIS OF LEAKAGE RADIATION THROUGH
MLC LEAVES
S. Yasuharu1
1
KOMAZAWA U NIVERSITY, sato laboratory, Tokyo, Japan
Purpose: The first objective of this study is to analyze simply the componentof leakage radiation measured by the diode detector. The second aim is toevaluate the characteristic of the MLC from our data obtained.
Materials: A Varian Clinac iX linear accelerator which has an 120-leaf HighDefinition Multileaf Collimator ( HD120TM MLC ) was used. The leakage radiation through MLC was measured with PTW Diode E type 60017, at 100
cm source to surface distance and a depth of 1.5 cm which is approximately
maximum depth dose in a water phantom, PTW SCANLIFT . Dose rate was
set to 400 MU / min.The field size defined by the jaw was kept at constant
100 cm2 . MLCs were set to block the entire open area. Both sides of the leaf
end were shifted from central axis to 10cm on the right to except transmission
derived from rounded leaf tip. The diode detector was transferred perpendicular to leaf travel in increments of 1 mm.To analyze the component of theleakage, the composite function calculated by Gnuplot with FORTRAN cord
was fitted to measurement value. The composite function was consisted ofmulti-function which can be separated into two Gauss function and one Linear function. Finally, both the measured value and the calculated value werereferenced to the value of central axis of open area. In addition, the fitting accuracy of the composite function using Gnuplot was estimated by root meansquare ( RMS ).

S 414

D OSE MEASUREMENT : N OVEL DETECTORSD OSE MEASUREMENT : N OVEL DETECTORSResults: The leakage radiation from a pair of abutment leaves was focusedon. Measurement value of cross-leaf leakage showed the rhythmicity whichwere composed of a big wave and a small wave in the profile, which was dueto the cross-sectional MLC which have Tongue and Groove design. A pairof abutment leaves having Tongue and Groove design produced two typesof inter-leakage. The component of leakage through a single narrow slit wasapproximated by Gauss function. From the obtained calculation value, theratio of inter-leakage 1 and inter-leakage 2 to reference value were 0.389 %and 0.118 %, respectively. The sum of component of the intra-leakage andthe leaf scatter was approximated by Linear function. The contribution of theintra-leakage and the leaf scatter in reference value was about 0.964%. This
indicates that the approximate calculation in this study was very sufficient,because RMS value between measurement values and calculation values
was 0.012.
Conclusions: The components of leakage radiation from MLCs having
Tongue and Groove design includes two types of Inter-leakage, a Intraleakage and a leaf scatter. A Tongue and Groove design made the component of leakage radiation complicated and reduced the component of a Interleakage, but increased the component of a Intra-leakage and a leaf scatter.
1111 poster
THE QUANTITATIVE ASSESSMENT OF MAYNEORD FACTOR AT
DIFFERENT ENERGY, FIELD SIZE AND SOURCE TO SKIN DISTANCE USING MONTE CARLO SIMULATION AND EXPERIMENTAL
MEASUREMENT
S. A. Vaezzadeh1 , M. Allahverdi2 , H. A. Nedaie3
1
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Tehran, Iran Islamic
Republic of2
T EHRAN U NIVERSITY OF M EDICAL S CIENCES R ADIATION O N, Tehran, Iran
Islamic Republic of3
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Cancer Institute, Tehran,
Iran Islamic Republic ofPurpose: When two source-to-skin distances (SSD) use for treatment, thecorrection of Percent depth doses (PDD) from one SSD to another consistof two components; the inverse square law correction component, as represented by Mayneord factor (FM) and the Scatter correction component, which
is often ignored. In this study, the accuracy of FM quantitatively was evaluatedusing Monte Carlo (MC) simulations.
Materials: MC simulations of Varian clinac 2100CD using MCNP code were
implemented. Based on PDDs, FM at two energies (6MV and 18MV), four
field sizes (10x10, 20x20, 30x30 and 40x40 cm2) and three SSDs (80, 100
and 110 cm) were calculated and analyzed for each combination. The correspondent experimental measurements were performed using PTW Dosimeter (0.125 ionization chamber) in the water tank (50x50x70 cm3). Finally, FM
was calculated by its analytical formula for those same fields.
Results: FM results from simulations, experimental measurements and analytical formula calculations were analyzed and differences were quantified foreach case. For the case of 80 cm vs. 100 cm SSDs, Mean differences between calculation and measurement were 2% and 3% while mean differences
between simulation and measurement were 0.7% and 1% for 6MV and 18MV
respectively. For 110 cm vs. 100 cm SSDs, Mean differences between calculation and measurement were and Mean differences between simulation andmeasurement were 0.7% and 1.0% whilst mean differences between simulation and measurement were 1.1% and 1.5% for 6MV and 18MV respectively.
Conclusions: Because MC simulations have lower differences than calculations with measurements for all cases, it could give more accurate result
for calculation of dose at the desired point. Since overall uncertainty in thedelivery of absorbed dose to the target volume is 5%, Scatter correction component should be considered to calculate accurate dose at a specified point
especially at 6MV.

not proportional to absorbed dose. Building on existing research carried out
at the NPL, we aim to create a tissue-equivalent detector primarily for microdosimetry of protons and light ions in order to better understand the biologicaleffect of different treatment modalities. The detector is based on the Inductive Superconducting Transition-Edge Detector (ISTED) designed at the NPL,
where we intend to extend the technology’s current application in low energy
photon detection to the dosimetry of protons and ions. Work has been carriedout by Kellerer et al. to develop a method for using microdosimetric spectra
to predict the relative biological effectiveness (RBE) of ions. It is our intention
to use microdosimetric spectra measured with our detector to calculate RBE.
The device is at present in the design and initial production phase and Monte
Carlo simulations are used to aid this design process.
Materials: Simulations of microdosmetric spectra were performed with
Geant4 version 4.9.3. For electromagnetic interactions, low-energy models
were used for all particles using the default ICRU Report 49 stopping power
parameterisation for protons. For non-elastic nuclear interactions the Bertini
Intra-nuclear Cascade models were used. The phantom was made of Perspex containing a spherical detection region of 3 mm diameter composed of
low-pressure tissue equivalent propane gas equivalent to a 1µm sphere oftissue. The secondary production range cut was set to 30 nm in the absorber
giving an energy threshold of 100 eV for electrons/photons. Simulations of
4 MeV protons and 194 MeV/u carbon ions have been carried out to determine the final absorber dimensions and material. The results of the carbon
ion simulations were compared with measurements recorded by Gerlach etal. using a TEPC.
Results: The calculated spectra compare qualitatively well with the data from
Gerlach et al. although a higher proportion of low energy interactions were
found in the simulation. Simulations of potential absorber geometries using
a 4 MeV proton beam show microdosimetric spectra peaking at about 10
keV/µm with a width of 10 keV/µm. For absorbers of 15 35 µm total thickness split into 0.1 µm layers, a small increase in the number of interactions
above 15 keV/µm was found as a function of depth.
Conclusions: Geant4 simulations of microdosimetric spectra were performed to aid the design of the microcalorimeter. Following these simulations
a range of detectors sized between ~25 µm and 40 µm square are now in
production. Whilst the larger size reduces the sensitivity it simplifies the production. In future more detailed simulations of the exact detector geometry
as produced will be performed to assess corrections to measured microdosimetric spectra.

1. F. Shez-Doblado et al., "Neutron-induced second cancer risk estimation in patients under radiotherapy by means of an online in-vivo
dosimeter" 11th symposium on neutron and ion dosimetry, iThemba
Laboratory for Accelerator-Based Sciences, Cape Town, South Africa
12-16 October 2009

ACTIVE ON-LINE NEUTRON MONITOR FOR HIGH MEGAVOLTAGE
RADIOTHERAPY
F. Gomez1 , F. Sanchez-Doblado2 , J. Marin-Muñoz3 , X. L. González Soto4 ,G. A. Araceli4 , M. Zapata-Criado1
1
U NIVERSIDADE DE S ANTIAGO DE C OMPOSTELA, Física de Partículas,
Santiago de Compostela, Spain
2
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Sevilla, Spain
3
CIEMAT, Sensors and electronics, Madrid, Spain
4
U NIVERSIDADE DE S ANTIAGO DE C OMPOSTELA, Santiago de Compostela,
Spain
Purpose: High megavoltage radiotherapy modalities have the undesired outcome of an additional neutron dose delivered to the patient. Due to the large
scattered photon fluence and its pulsed nature it has been difficult to consider an active system as a real alternative to passive methods of neutron
detection inside radiotherapy room. From the research of Single Event Upset in digital devices it has appeared a LET discriminating methodology that
overcomes the mixed photon-neutron radiation field problems. Several articles have been published demonstrating the reliability and performance of
this technique [1, 2, 3]. Several problems of the first version of the instrument have been addressed and considered to produce a new planar version
with mapping capabilities and faster readout, while keeping the sensitivity ofprevious version.
1. F. G, A. Iglesias and F. Shez-Doblado 2010 Phys. Med. Biol. 55 1025

1112 poster

3. C. Domingo, F. G, F. Shez-Doblado, G.H. Hartmann, K. Amgarou, M.J.
GarcFust.T. Romero, R. Bttger, R. Nolte, F. Wissmann, A. Zimbal, H.
Schuhmacher 2010 Rad. Meas. 45 1513-1517

Purpose: The Bureau International des Poids et Mesures has recommended
to define a new quantity to account for the biological effect of ionising radiation used in radiotherapy as the biological effect of proton and ion beams is

to possess a 15% sensitivity variation when exposed to doserates varying
from 0.012cGy to 0.12cGy. A recent study has also shown that parallel-platechambers, which are the reference dosimeter for electron beams, exhibit significant depth and energy dependence in electron beams2 , especially for low
energy electrons. In light of these facts, there is a need to revisit the questionof silicon diode response in electron beams.
Materials: We used a single scanning water equivalent plastic scintillation detector (PSD) mounted on a high-precision (0.1 mm reproducibility) scanningtank to measure depth-dose curves in 6, 12 and 18 MeV electron beams froma Varian Clinac iX. The PSD dosimeter used in this study consists in a 1 mm
diameter and 2 mm long plastic scintillating fiber coupled to a clear non scintillating fiber. The scintillation photons are output onto color charge coupleddevice camera (CCD). The prototype is described in detail in Ref. 2. We alsomeasured depth-dose curves using three types of diodes: IBA dosimetry EFD
and SFD and PTW 60012 unshielded. The diodes reading was corrected for
known doserate dependencies. We assumed, based on previous studies2 ,that the PSD was water equivalent and did not exhibit any significant dose,
doserate or energy dependencies. The PSD was then considered to be thereference depth-dose, i.e. to be free of artifacts for the subsequent analysis.
We calculated the ratio of PSD to diode dose for each measurement depth
and energy by dividing the normalized depth-doses. This ratio is termed the"relative perturbation factor" in accordance with ion chamber dosimetry practice.
Results: Figure 1 shows the relative perturbation factors for the EFD, SFD
and PTW diodes for 6 MeV. Also shown are Monte-Carlo results from the
Wang and Rogers paper3 . The response of all three diodes differs from thatof the PSD to various degrees for the buildup region and the Bremmstrahlung
tail. All diodes tend to overestimate the Bremmstrahlung component. All
diodes furnish adequate depth-dose curves from dref to close to R50. However, the relative perturbation factor is significantly higher than predicted byMonte-Carlo, especially at large depths (> R50) and low energies.

1113 poster

Dose measurement: Novel detectors
A NOVEL DETECTOR FOR THE MEASUREMENT OF MICRODOSIMETRIC SPECTRA FOR PROTONS AND LIGHT IONS
S. Galer1 2 , H. Palmans1 , D. Shipley1 , L. Hao1 , A. Nisbet3 , K. Kirkby2
1
N ATIONAL P HYSICAL L ABORATORY, Teddington, United Kingdom
2
U NIVERSITY OF S URREY, Guildford, United Kingdom
3
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, Guildford,
United Kingdom

Results: Several previous works within the NEUTOR collaboration [4] have
proved that (once calibrated) the detector readout could be used for the estimation of patient neutron exposure at least for each treatment plan class(such us pelvis, head & neck, etc). Figure 2 was obtained dividing the dose
measured through PADC detectors inside an anthropomorphic phantom normalized to the digital detector readout placed inside the radiotherapy room.
As it can be appreciated in the Figure 2, the dose to detector readout ratio
is quite independent (up to 15%) from the linac energy and room size.Figure
2 Caption: Neutron dose at different points in an anthropomorphic phantom
normalized to the digital detector readout for different clinical facilities.

S 415

2. F. G, F. Shez-Doblado, A. Iglesias, C. Domingo 2010, Rad. Meas. 45
1532-1535

Materials: The detector is based on COTS (Components Off the Shelf) using
128 SRAM with 512 kiB size (8 bit words) (Figure 1). The system is basedon the detection of memory upsets in the array that is managed through anembedded microprocessor. The system has serial readout and represents
the second generation of the device under patent US 2010/0258732 A1.
Figure 1 Caption: New version of the planar neutron monitor showing the 128
SRAM array.

Conclusions: The diodes tested exhibit little perturbation for depths between
dref to close to R50. However, the perturbation increases rapidly for depths
greater than R50.
1. M McEwen and C Ross, "Unexpected Doserate Dependencies of
Diodes for Beam Scanning", Med. Phys. 35,pp. 2920-2920 (2008).

Conclusions: The new planar version of the neutron monitor will solve problems arising from self-neutron absorption and will provide a faster and morereliable device for monitoring the neutron production in radiotherapy facilities.
1114 poster
DEPTH-DEPENDENT RESPONSE OF SILICON DIODES IN ELECTRON BEAMS
F. Lacroix1 , M. Guillot2 , M. McEwen3 , L. Beaulieu4
1
CHUM - C AMPUS N OTRE -DAME, Radio-oncologie, Montréal, Canada
2
H OTEL -D IEU DE Q UEBEC CHUQ, Radio-oncologie, Montreal, Canada
3
N ATIONAL R ESEARCH C OUNCIL, Ionizing Radiation Standards, Ottawa,
ON, Canada
4
C ENTRE H OSPITALIER U NIVERSITAIRE DE Q UÉBEC, L’H ÔTEL -D IEU DEQ UÉBEC, Radio-oncologie, Quebec, Canada
Purpose: It is commonly assumed, based on qualitative comparisons to ion
chamber measurements, that silicon diode response is independent of depth
in electron beams. However, the AAPM TG-25 did point out that the stopping
power ratio decreases by up to 6% with decreasing electron energy below 5
MeV. This is likely to affect depth dose curves at depth where the electron energy drops. It has also been shown recently that silicon diodes exhibit doserate dependencies1 ; for example, the PTW 60012 electron diode was shown

2. F. Lacroix, M. Guillot, M. McEwen, C. Cojocaru, L. Gingras, A. S. Beddar, and L. Beaulieu, "Extraction of depth-dependent perturbation factors for parallel-plate chambers in electron beams using a plastic scintillation detector", Med. Phys. 37, 4331 (2010).
3. L. L. W. Wang and D. W. O. Rogers, "Monte Carlo study of Si dioderesponse in electron beams", Med. Phys. 34, 1734 (2007)

1115 poster
DETERMINATION OF CORRECTION FACTORS IN KILOVOLTAGE
ENERGY RANGE OF THE ONEDOSETM SYSTEM
A. Lo Bosco1 , M. D. Falco2 , G. Rinaldi3 , L. Strigari4 , M. D’Andrea5 , F.
Quagliani5 , R. Santoni6
1
TOR V ERGATA U NIVERSITY, Department of Physics, Rome, Italy
2
TOR V ERGATA U NIVERSITY G ENERAL H OSPITAL, Department of Diagnostic
Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy,
Rome, Italy
3
T EMA S INERGIE, Faenza, Italy
4
R EGINA E LENA C ANCER I NSTITUTE, Roma, Italy
5
N ATIONAL C ANCER I NSTITUTE R EGINA E LENA, Laboratory of Medical
Physics and Expert Systems, Rome, Italy
6
P OLICLINICO TOR V ERGATA, Roma, Italy

S 416

D OSE MEASUREMENT : N OVEL DETECTORSD OSE MEASUREMENT : N OVEL DETECTORS

Purpose: We studied the OneDoseTM System (ODS), using MOSFET
solid-state radiation detectors designed for high-energy photon radiotherapy
beams, to find the energy and Field Of View (FOV) correction factor to connect the MOSFET reading to dose in kilovoltage (kV) energy range for diagnostic and interventional procedures (IR). The aim was to have an alternativeand easy to use system to measure the Entrance Surface Dose (ESD) for invivo dosimetry.
Materials: All measurements were performed on a C-arc GE Medical System
Innova 4100. To calibrate ODS in kV energy range, a reference setting (RS)(kVp = 80, FOV = 40 cm x 40 cm, mAs = 500, Source Surface Distance(SSD) = 80 cm) was fixed. The doses measured with ODS were compared toreference doses measured with a PMX-III RTI Electronics. We attached both
the dosimeters on the entrance surface of an air equivalent phantom at thesame time. The correction factor for energy dependence, named CkV , wascalculated as the ratio between the reference incident air kerma measured
by an ionization chamber and the same value measured by ODS in RS. To
test if CkV depended on mAs values, this test was repeated for others two
different mAs (250 and 700 mAs) using the same experimental set-up. This
test was also repeated on a different C-arcs used in IR using the same set-up
configuration. To simplify the comparison, a mAs fixed values (250) has beenchosen. Finally, a FOV dependence in RS varying only the FOV parameterhas been analized.
Results: The response of CkV factors was roughly uniform from 50 to 110
kV (at 500 mAs). The CkV values versus kV using all mAs input (250, 500,700) have been then graphed and a best fit function has been reserched. A
fifth grade was the best fit function with a good R2 value (0,975). It can beconcluded that CkV is independent from mAs in the energy range valuated.
Finally, it has been found that the energy correction factor CkV was independent from the X ray tube utilized, finding a difference among the two systems
analysed better then 2 %; only the lower kV values (50 and 60) showed alittle difference. Probably this could be due to a small sensitivity of the ODS
in this range. The CFOV values were graphed versus FOVs. The results
showed that the best fit function was a polynomial of the fourth grade (R2 =1).
Therefore, replacing the kV and FOV values in the respective fit equation, thecorresponding CkV and CFOV can be determined.
Conclusions: We found the best fit function for CkV (at different mAs input)
and CFOV dependence and also that CkV was independent of the X ray tube
utilized. This would be that the variation on the output are inside the errors
and the variability of the system used. It can be concluded that this system
in diagnostic X-ray energies, after applying proper corerction factors, can besuitable in measuring the ESD during IR.
1116 poster
DOSIMETRIC COMPARISON OF THE ONEDOSE MOSFET SYSTEMAND GAFCHROMIC XR TYPE QA IN RADIOLOGICAL ENERGY
RANGE
M. D. Falco1 , A. Lo Bosco2 3 , G. Rinaldi4 , L. Strigari5 , M. D’Andrea6 , F.
Quagliani6 , M. Rebuzzi1 , R. Santoni7
1
TOR V ERGATA U NIVERSITY G ENERAL H OSPITAL, Department of Diagnostic
Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy,
Rome, Italy
2
A ZIENDA ASL R OMA H, Rome, Italy
3
TOR V ERGATA U NIVERSITY, Physics Department, Rome, Italy
4
T EMA S INERGIE, Faenza, Italy
5
N ATIONAL C ANCER I NSTITUTE R EGINA E LENA, Rome, Italy
6
N ATIONAL C ANCER I NSTITUTE R EGINA E LENA, Laboratory of Medical
Physics and Expert Systems, Rome, Italy
7
P OLICLINICO TOR V ERGATA, Roma, Italy
Purpose: In testing the dose accuracy of a new dosimetric system, the comparison of the measurements with values obtained with the reference systemused for the calibration of the new system, could obscure some flaws. The
aim of this work is to compare, in the radiological energy range (80 kV), thedoses measured using the MOSFET based One Dosestem, originally precalibrated by the manufacturer using a 60 Co source under full buildup, to thosemeasured with gafchromic film XR Type QA , the latter being an alternativeand independent system different from the Ionization Chamber used to determine the energy kV response of the One Dosestem itself.
Materials: The measurements have been performed on a C-arc GE Medical
System Innova 4100. For all measurements (five dose levels ranging from15 to 100 mGy, obtained changing mAs), the MOSFET detector was placed,
together with a single piece of gafcrhomic, at the centre of the FOV and on
an air equivalent phantom positioned on the Image Intensifier Surface (reference settings : FOV= 40 cm x 40 cm, mAs = 500; kVp = 80, SSD = 50 cm).
In addition, a Ionization Chamber (IC), positioned near the two system, measured the reference dose. The MOSFET dose has been determined from thereading of the MOSFET by applying the energy and FOV calibration factors
derived from the MOSFET energy calibration curves obtained during the calibration procedure of the One Dosestem in the radiological energy range. The
gafchromic film dose, for each dose level, has been determined from the corresponding Gray Level (GL), using the dose response curve of the gafchromic
system. Such curve had been determined in the same experimental set-up(80 kVp and a FOV of 40 cm x 40 cm) as a fourth order polynomial with anmaximum uncertainty of 6% as the best to fit the curve.

Results: The doses measured with the MOSFET agree with those measured
with gafchromic films, within a maximum percentage difference of 9% (Table1). In addition, the maximum percentage difference between the reference
doses measured with the IC and the doses measured with the MOSFET andgafchromic films, are 7% and 8%, respectively. These results are within thedose error of 20% stated for radiological practice.
Conclusions: The One Dosestem is accurate in reporting doses in the radiological energy range. Tanks to the easiness of use and to the absenceof connecting wires, it can be considered suitable to measure patient’s skindose in radiological procedures.

1117 poster
EPID CHARACTERISATION FOR DOSIMETRY OVER A WIDERANGE OF PHOTON ENERGIES
J. Pearce1 , S. Nijsten2 , C. Clark3 1 , S. Duane1 , M. Podesta2 , L. Persoon2 ,D. Shipley1 , W. van Elmpt2 , F. Verhaegen2
1
N ATIONAL P HYSICAL L ABORATORY, Radiation Dosimetry, Teddington,
United Kingdom
2
MAASTRO CLINIC, Maastricht, Netherlands
3
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, Guildford,
United Kingdom
Purpose: The objective of this study was to explore the dose-response characteristics of an amorphous silicon (a-Si) EPID over a wide range (4-25 MV)
of clinically relevant photon energies. The investigation covered ghosting andimage lag effects as well as field size dependence.
Materials: EPID measurements were performed using a commercial a-Si detector (Perkin Elmer, USA) on a modified Synergy linear accelerator (Elekta,
Crawley, UK). This accelerator is a unique facility that can be configured todeliver 7 X-ray beam energies, covering the range 4-25 MV. Two basic characteristics were investigated. First, the ghosting and image lag characteristics
were determined by delivering a range of monitor units (MU) between 1 and
700 MU. Image lag and ghosting were further investigated by analysing theresidual image signal after beam off. Second, the field size dependent response of the EPID was measured for field sizes ranging from 3x3 to 26x26
cm2 .Each EPID image was corrected for gain and dark current effects. Relative response measurements were made using a calibrated CC13 ionisationchamber (IBA Dosimetry, Louvain, Belgium) in a scanning water tank connected to a Dose 1 electrometer (IBA Dosimetry, Louvain, Belgium). Dosein water measurements were performed at a source-to-chamber distance of
160 cm and at a depth of either 5 or 7 cm, depending on beam energy.The
relative EPID response (REPID) was defined as ICORR/Dref, where ICORR
is the average pixel value within a region-of-interest of 1x1 cm2 at the central
beam axis in the EPID image after correction for gain and dark current, andDref is the reference dose measured using the ionisation chamber. REPID
was determined as a function of time after the beam was turned for all photon
energies in order to examine ghosting of the signal.
Results: Figure 1 shows the EPID response as a function of field size normalised to the response for a 10x10 cm2 field. Higher photon energies cause
larger field size dependent differences in relative EPID response.Results for
the EPID response as a function of delivered MU showed an under-response
for low MU. No effect was observed when changing the pulse repetition frequency of the linac.Image lag and ghosting effects illustrated that the residual
signal was less than 0.5% of the maximum signal at all energies within 10s of
beam off.

Figure 1. Relative EPID response as a function of field size for an a-Si EPID
at 7 photon energies over the range 4-25 MV.
Conclusions: An a-Si EPID has been characterised over the range 4-25 MV.
The greatest energy-dependent effect was found to be the field size dependence, with the EPID showing a change in response with field size of up to
18%. Variations in image ghosting properties were observed for the various
photon energies. The characterisation described in this abstract is necessary
for open field dosimetry using EPIDs.

S 417

Purpose: Since several years, polymer gel dosimeters have been proposed
for three-dimensional dose verification of conformal radiotherapy treatments.
Clinical use of normoxic polymer gel dosimeters however has been limited
to a few radiotherapy centers worldwide partially because of a lack of reproducibility. In this study the intra-batch accuracy and precision of polymer gel
dosimeters is assessed.
Materials: Eight similar spherical glass recipients (250 ml) and nineteen
test tubes (12 ml) were filled with a polymer gel consisting of gelatin (6%),
acrylamide (2.5%), N,N’-methylene-bis-acrylamide (2.5%) and the antioxidant THPS (5 mM).The spherical phantoms were irradiated using a purposebuild phantom holder on an Elekta Synergy linear accelerator (figure a). The
centre of the spherical recipients was positioned at the irradiation isocentre. The treatment was composed of three 6 MV photon beams of size 3.2
x 3.2 cm, collimator angle 0◦ , gantry angle -60◦ , 180◦ and 60◦ and fluence 375 MU, 525 MU and 150 MU. A total dose of 11.24 Gy was given at
the centre of the spherical phantoms as calculated by the treatment planningsystem (TPS) Pinnacle 8.0m and verified with a pinpoint ion chamber measurement. The nineteen test tubes were irradiated with a predetermined dose
ranging between 0 and 15 Gy. The eight irradiated spherical phantoms andtest tubes were positioned in a clinical NMR scanner (Siemens Avanto 1.5T)
using the same phantom holder and were scanned one-after-the-other (figure b). Quantitative NMR spin-spin relaxation rate images (R2-maps) wereacquired in a transverse plane (2D) through the isocentre. The 2D measurements for all eight phantoms were repeated at times 6 hours, 30 hours and
54 hours post-irradiation. In addition, full 3D R2 distributions of all eight phantoms were acquired 92 hours post-irradiation. All R2-maps were converted todose maps using an R2-dose calibration plot derived from the test tubes. A
quantitative comparison between measured and planned dose distributions
was made.

1118 poster
FREE-RUNNING SYNC CORRECTION FOR MV-IMAGING WITH
ASI:H FLAT PANELS
M. Mooslechner1 , M. Bernhard2 , S. Huber1 , H. Weichenberger1 , P.
Steininger1 , F. Sedlmayer12 , H. Deutschmann12
1
PARACELSUS M EDIZINISCHE P RIVATUNIVERSITÄT, Institute for Researchand Development on Advanced Radiation Technologies, Salzburg, Austria
2
U NIVERSITY C LINIC S ALZBURG, University Clinic for Radiotherapy andRadio-Oncology, Salzburg, Austria
Purpose: Native image frames captured by electronic portal imaging devices
show a range of artefacts, that have to be eliminated by clinical or dosimetrical applications. During irradiation with lower dose rates, at low MU imaging,moving vertical stripes (periodic synchronization artefacts) become a dominant feature of image frames, if the panel is operated in free-running mode.
Materials: We introduce a sync correction method, which is based on a theoretical model describing the interferences of the panel’s readout procedure
with the linac’s pulse repetition frequency (PRF). The used amorphous silicon flat panel detector (PerkinElmer) comprises 2 x 8 subpanels with 128
x 512 pixels each (total 1024 x 1024 pixels), which are read column-wisefrom the outside to the inside of the active area (16 pre-amble columns, 512
frame columns, 16 post-amble columns; readout time 796 µs/column). Using
the fastest free-running mode, a frame takes 433 ms acquisition time. Depending on the applied PRF, a certain number of pulses (1/64 MU/pulse) is
captured per frame. The amplitude of the periodic sync signal as well as its
period can be calculated analytically, while the phase of the sync stripes canbe determined per frame by cross correlation with the theoretical interference
model. The process is self-triggering, and the sync artefacts can be eliminated multiplicatively in dose-calibrated frames without additional information
about thyratron pulse timing.
Results: For all PRFs (Elekta Synergy 6.25, 12.5, 25, 50, 100, 200 and
400 pps) excellent single frame image quality is achieved. The sync stripes
are successfully eliminated. Remaining stochastic spikes (single columns
affected) can be corrected by column specific median filtering (frame postprocessing) and are averaged over buffer accumulated frames.
Conclusions: The presented free-running sync correction improves absolute
dosimetry and clinical image quality. The method supports the developmentof new imaging applications, such as low-MU imaging at higher frame rates(e.g. to track moving gold fiducials in the lung). Simultaneous kV / MV acquisition benefits from new possibilities of MV scatter removement from kV
images before reconstruction. Adaptive IGRT protocols become even feasible in VMAT plans, where doserate / PRF is changing during delivery.
1119 poster
INTRA-BATCH ACCURACY OF NORMOXIC 3D POLYMER GELDOSIMETERS
J. Vandecasteele1 , Y. De Deene12
1
G HENT U NIVERSITY H OSPITAL, Department for Radiation Oncology andExperimental Cancer Research, Ghent, Belgium
2
U NIVERSITÉ DE S HERBROOKE, Département de médecine nucléaire et deradiobiologie, Sherbrooke, Canada

Results: The R2-dose calibration plots were found to be mono-exponential.
The variations in the dose-R2 calibration plots between the eight measurements correspond with equivalent relative dose variations of 8.06%, 3.05%,
1.12% and 4.3% for measurements performed 6h, 30h, 54h and 92h postirradiation respectively. During the first measurements (6h post-irradiation)
the equivalent relative dose variation was more pronounced due to postirradiation chemical instabilities.The equivalent relative dose variations in theisocentre of the eight phantoms amount to 7.86%, 4.71, 2.86% and 1.43% respectively. The absolute deviation between the TPS calculated dose and thegel measured dose in the isocentre amounted to 6.49% at 6h, 9.12% at 30h,
11.01% at 54h and 12.88% at 92h post-irradiation. The measured dose maps
were normalized to the ion chamber measurements for all gel phantoms individually and dose difference maps and gamma maps between gel-measured
and calculated dose distributions were constructed in both 2D and 3D.
Conclusions: All 2D and 3D dose distributions (calibrated individually) show
large deviations in absolute dose when compared to TPS and ion chamber measurements. However, an intra-batch correspondence in equivalentrelative dose within 5% is found between the different spherical phantoms
which suggests that a calibration with a phantom of similar volume can be
performed.
1120 poster
MICROSCOPIC AND SPECTRAL DOSIMETRY USING GAFCHROMIC FILMS AND SURFACE ELECTRON MICROSCOPY
F. Van den Heuvel1 , G. De Kerf1 , S. Maria2 , E. Van Limbergen1 , E.
Couteau3 , S. Nuyts1 , J. P. Locquet3
1
K ATHOLIEKE U NIVERSITEIT L EUVEN, Dept of Experimental Radiotherapy,
Leuven, Belgium
2
K ATHOLIEKE U NIVERSITEIT L EUVEN, Dept. Metallurgy and Material
Engineering, Leuven, Belgium
3
K ATHOLIEKE U NIVERSITEIT L EUVEN, Solid State Physics and Magnetism
Section , Leuven, Belgium
Purpose: The use of high-Z nano-particles (NP) increases the dose in the
nearby volume by absorbing more photons of keV energy. The resulting electrons deposit the dose locally. Additionally, Auger electrons are generated.

S 418D OSE MEASUREMENT : SMALL AND COMPOSITE FIELDS AND FLATTENING FREE

D OSE MEASUREMENT : N OVEL DETECTORS

These very low energy electrons can contribute to dose in a high LET modeincreasing the effectiveness of the dose deposition. In combination with tumor specific agents such a dose deposition mechanism could provide an efficient methodology to increase dose to microscopic disease in addition to dosenormally delivered to the tumor.To quantify dose enhancement and spectralchanges in the vicinity of these particles we propose the use of GaF-chromic
film which can be analysed using scanning electron microscopes (SEM) toyield microscopic insight in the processes at hand. It is the goal of this paper
to outline the methodology and use of these films under these conditions.
Materials: Measurements were performed using a clinical RT-simulator running at 40kVp. GaF-chromic active layer only film (International Specialty
Products, Wayne, NJ, USA) was coated with a layer of gold NP’s of about
30nm thick. The film was irradiated with the NP downstream from the source
to a dose of 0.01Gy. As control a radiate and non-radiated film was used. The
three films were analyzed using scanning electron microscopy on top and bottom of each films.The samples were characterized by means of the SEM unitof the FEI Dualbeam Nova 600 Nanolab, operating at 2kV and 53pA. As the
GaF Chromic films are not conductive, the surface is coated prior to SEM observations with a thin layer of Au in a sputter coater, which uses an Ar-plasma
on a gold target (deposition time of about 1 min.). The samples are placedoutside of the plasma, however, some heating (<50C) occurs during the deposition.The resulting images showed a landscape with a number of cracks
which we hypothesize to be electron tracks. The images were processed using a skeletonization technique based on mathematical morphology, yielding
the number of cracks and a quantification of the track length. This was compared to a monte carlo simulation of the setup as described above using a
mono-energetic 40keV photon beam. Histograms of the track lengths and of
the continuously slowing down range (CSDA) matched to the electron energy
tally in the MC-simulation were produced.
Results:

The figure presents a SEM image of the GaF-chromic film (left), the subsequent skeletonization (middle) and the resulting histograms, track length(top) and CSDA range (bottom). Reasonable agreement between the two
histograms exist. The low energy portion of the MC-simulation fails as electrons with energies lower than 10keV are not tracked. We also see a larger
peak at the track length histogram most probably due to the finite resolutionof the film.Regarding total dose a larger number was found in NP-coated films
compared to non coated. Furthermore, the average length of the cracks increased. Also the reference film showed cracks but in smaller numbers.
Conclusions: We have shown that GaF-chromic films can be used to gain insight in the overall dose deposition and enhancement at a microscopic level.
Additionally, the spectral information can readily be obtained also. In a further development we will report on the behavior of this novel measurement
approach with varying dose levels and changes in spectrum.

The increase density of superparamagnetic nanoparticles is the indication of
possible tumor.
Results: Preliminary results show that the method can detect 50 100 superparamagnetic nanoparticles, which practically suggests detection of single
malignant cells (in which ~100 antibodies per cell attract the same number ofSN).
Conclusions: The method offers a method to determine the position and thecorresponding spatial distribution of superparamagnetic nanoparticles, thus
allowing for the conclusion of possible malignant cells.
1122 poster
SILICON DIODE ARRAYS FOR SMALL FIELD QA AND STEREOTACTIC RADIOSURGERY/THERAPY VERIFICATION
S. Manolopoulos1 , G. Heyes1 , T. Anaxagoras2 , N. Allinson2 , G. Moldovan3 ,A. Kirkland3
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Department of Medical Physics, Birmingham, United Kingdom
2
U NIVERSITY OF L INCOLN, Computer Science, Lincoln, United Kingdom
3
OXFORD U NIVERSITY, Department of Materials, Oxford, United Kingdom
1

Purpose: Small photon fields are increasingly used in modern radiotherapy and especially in IMRT and stereotactic radiosurgery/radiotherapy(SRS/SRT) treatments. Uncertainties related to small field profile measurements, and in particular in the penumbra region, can introduce significant
systematic errors to the overall treatment process. We will report progress
to create novel dosimeters with sufficient spatial resolution for real time measurements at steep dose gradients by utilising active pixel sensor technology,
originally developed for particle physics and microscopy.
Materials: Diode arrays manufactured in monolithic silicon, using fabrication
processes typically encountered in microelectronics, have been used successfully for the measurement of the basic beam data of clinical linac based
radiosurgery systems (S. Manolopoulos, ESTRO2009). Whereas, our first
prototype (DOSI) was proved capable of characterising the beams of BrainLAB’s conical collimator SRS system with sub-millimetre spatial resolution
and in real time (S. Manolopoulos et al., Phys. Med. Biol. 54 (2009) 485),
its usefulness as a clinical dosimeter was restricted by the nature of its design (1D). Therefore, our investigations continue with the adoption of 2D arrays of active pixel sensor technology based on complementary metal-oxidesemiconductors (CMOS).

1123 poster
SIMPLE PROPOSAL FOR DOSIMETRY WITH AN ELEKTAIVIEWGTTM ELECTRONIC PORTAL IMAGING DEVICE (EPID)
J. Liebich1 , J. Licher1 , C. Scherf1 , E. Kara1 , N. Koch1 , C. Rödel1 , U.
Ramm1
1
K LINIKUM DER J OHANN W OLFGANG G OETHE U NIVERSITÄT, Klinik fürStrahlentherapie und Onkologie, Frankfurt, Germany
Purpose: An electronic portal imaging device (EPID) is used to control patient setup and positioning during fractionated radiotherapy. Due to the risingcomplexity and conformity of irradiation techniques the demand for an accurate verification of the dose delivered to the patient has also increased. The
purpose of this study was to investigate a simpleproposal for dosimetry with
an Elekta iViewGTTM EPID using commercial software modules.
Materials: EPID measurements were performed using an Elekta iViewGTTM
EPID on a linear accelerator with 6 MV X-ray beam. To activate the software of the iViewGTTM for dosimetric purposes, it was used in the IMRTDosimetricWeighting mode. The EPID signal was studied for reproducibility, as
well as characteristics as a function of dose, dose rate and field size. As
reference system and for calculation an ionization chamber 0.3 cm3 , PTW
Freiburg, was used at the depth of maximum dose in a PMMA phantom at
160 cm SDD (source detector distance). A series of experiments, comparing the response of the flat panel imager and measurements of dose withthe reference system, determines the parameters for the calibration model.
EPID measurements were also compared with calculations of the treatment
planning system (TPS), Oncentra Masterplan. For additional crosschecks wemeasured the profiles with a 2D-Array (PTW).
Results: We found a stable response of the EPID signal over a period of 14
months. It showed a non-linearity depending on dose up to 6.8 %. There were
low changes depending on dose rate up to 1.2 %. The relative output-factors,
as a function of field size, of the EPID reveal a steeper slope according to
the reference system. This implies different scattering characteristics of theEPID, which has to be adjusted with a correction factor for each pixel, considering the difference between the output factors of the EPID and the reference
system. For all fields the calibrated flat panel profiles match the measured
and calculated dose profiles with maximum deviation of 2 3 % for the infield region. In the high gradient areas we found higher differences. The
gamma evaluation indicates very good correlation between the two measurement systems EPID and the 2D-Array. The deviations between the EPID and
the TPS may indicate the accuracy of the calculation of the TPS in comparison to the dose distribution delivered by the linac for IMRT-fields. Especiallyin this case, the scattered radiation and the radiation of the interleaf leakage
could be underestimated by the TPS
Conclusions: The gamma evaluation indicates good correlation between
predicted and acquired EPID image. The EPID-based pre-treatment IMRT
verification method will help to improve the quality assurance procedure.
1124 poster
SMALL FIELD DOSIMETRY AND BEAM DATA ACQUISITION FOR
STEREOTACTIC RADIOSURGERY
C. Antoine1 , G. Heyes1 , S. Manolopoulos2
1
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Department of Medical Physics and Radiation Safety, Birmingham, United Kingdom
2
U NIVERSITY H OSPITAL B IRMINGHAM NHSFT, Department of Medical
Physics and Radiation Safety, Birmingham, United Kingdom

1121 poster
NEW METHOD FOR SUPERPARAMAGNETIC NANOPARTICLESMAPPING
P. Mavroeidi1 2
1
N ATIONAL AND K APODISTRIAN U NIVERSITY OF ATHENS, Department ofMedical and Experimental Physiology, Athens, Greece
2
N ATIONAL T ECHNICAL U NIVERSITY OF ATHENS, Laboratory of Metallurgy,
Athens, Greece
Purpose: Use of magnetic field sensor arrays to map the spatial (or space)
distribution of superparamagnetic nanoparticles under the influence of rotating magnetic field
Materials: The schematic of the device is illustrated in Figure 1. Uniform
rotating magnetic field is obtained in a cylindrical space by using three radial sinusoidal magnetic fields of frequency from 10 mHz to 10 Hz, by meansof the stator of a specially designed electric motor. Thus, the superparamagnetic nanoparticles (SN), being always in saturation, maintain their orientationon the direction of the rotating field.An array of 1 pTHz-1 sensitive magnetic
field sensors is continuously rotating around the rotating magnetic field witha low rotational frequency, i.e. between 3 to 30 mHz. The under test sample
is set in the area of the above mentioned cylindrical space. A special algorithm has been developed in order to calculate the position and the spatial
distribution of the SN.The method has been designed to detect the density ofthe spatial distribution of SN concerning magnetically targeted drug delivery:
SN of 5 nm + 2 nm mean diameter are covered by special proteins-liposoms
such as they could be the antibodies of the healthy and malignant cells. The
high concentration of SN in the malignant cells due to the high concentration of antibodies in these cells is monitored by the described methodology.

improvements in the treatment process, especially for busy radiotherapy departments.

Results: Basic beam data (PDD, OAR, ROF and beam profiles) for BrainLAB’s stereotactic conical collimator system were performed and comparedwith our hospital’s reference data using small "single point" dosimeters (PinPoint, diamond) and DOSI. Furthermore, SRS treatment plans, recalculated
in a solid water phantom, were measured and verified using the gamma analysis methodology, commonly employed in IMRT plan verification.
Conclusions: A novel dosimeter based on CMOS active pixel sensors wascapable of small field (<40 mm diameter) measurements and was successfully employed for the beam characterization of a clinical SRS system. Further
to our previous work with DOSI, its 2D measuring ability provides for a more
efficient operation (both AB and GT profiles measured simultaneously) andincreased flexibility (patient as well as machine specific QA). These coupledwith a PC-based, fully customisable data acquisition system (DAQ), should
enable real time planar dose distribution measurements and patient specific
QA for stereotactic radiosurgery/therapy, and thus providing with significant

Purpose: At our centre, Stereotactic radiosurgery treatments are performed
using field sizes down to 10mm diameter. Accurate measurements of percentage depth doses, output factors and off axis ratios are required within
the treatment planning system for dose calculation.The difficulties of taking
accurate dose measurements in small radiation fields have been well documented. The aim of this work was to assess the limitations of a range of
detectors, two micro ion chambers, a diamond detector and a DOSI detector- a linear array of diodes. For further details on DOSI see, Manolopoulos,
Wojnecki, Hugtenburg, Sidek, Chalmers, Heyes, Green, (2009).
Materials: All measurements were carried out under clinical conditions using
6MV bremsstrahlung photons from a Varian Clinac 600C. External collimators manufactured by BrainLAB were mounted onto the treatment head using
a bayonet locking mechanism. The available collimators varied in size from
7.5mm diameter to 35mm. Two Scanditronix-Wellhofer compact ionisationchambers, CC13 and CC01, with volumes of 13cm3 and 1cm3 respectively
were used for dose measurements. Along with a PTW type 60003, Diamonddetector and a novel detector, DOSI.The CC01, CC13 and diamond detectors
were used within an IBA Blue phantom 2 computerised scanning water phantom to measure output factors and profiles for the 7.5mm, 10mm, and 25mm
collimator. The DOSI detector was used within solid water to measure output
factors and profiles for 7.5mm, 10mm, 12.5mm, 15mm, 17.5mm, 20mm andS 419

25mm collimator sizes. All measurements were taken with an SSD of 925mm,
profiles were measured at isocentre and output factors at the depth of dose
maximum. The pixel size within the DOSI detector is 0.25mm; the diamonddetector was mounted in its optimal orientation for profile measurements, so
it had an active thickness of 0.1 to 0.4mm. The CC01 detector has an active
thickness of 2mm and the CC13, 7mm.
Results: There was reasonable agreement between output factors measured
for the 25mm collimator; however both of the larger ion chambers underestimated the output factors for the smaller fields, possibly due to volume averaging effects. A comparison of profiles measured using the CC13, CC01,
Diamond and DOSI detectors for the 10mm collimator is shown in Figure 1.

Conclusions: Penumbra broadening was evident from measurements takenusing the CC13 ion chamber, although the effect was reduced when using thesmaller CC01 chamber. The profiles measured with the diamond and DOSI
detectors were in reasonable agreement and sharper than those seen withboth ion chambers.For small field measurements, the use of solid state detectors should be considered. Penumbra broadening effects can be reduced
through the use of micro ion chambers although this effect is always seen due
to the range of electrons within the air cavity. Solid state detectors are available with a superior resolution, although they may potentially underestimate
the penumbra due to the higher atomic number in relation to tissue.

Dose measurement: small andcomposite fields and flattening
free
1125 poster
A NOVEL DIRECTION-SELECTIVE FLATTENING FILTER FOR
CLINICAL PHOTON BEAMS - MONTE CARLO EVALUATION OF A
NEW CONCEPT
N. Chofor1 , D. Harder2 , K. Willborn1 , B. Poppe1
1
P IUS - H OSPITAL, Radiation Therapy and Radiooncology, Oldenburg,
Germany
2
G EORG AUGUST U NIVERSITY, Medical Physics and Biophysics, Göttingen,Germany
Purpose: A new, small flattening filter has been designed for the Siemens
Primus linac, using a narrow steel cone for the direction-selective attenuation of the photons produced in the target. The direction-selective filter (DSF)
maintains the advantages characteristic for flattening filter free (FFF) conditions, such as the dose-rate enhancement, the reduction of photon andneutron leakage from the beam head/Gy in the treatment volume, and the
reduction of normalized peripheral dose (PD) levels. The DSF filter provides
flattened photon fields up to square fields of side length 10 cm. The DSF
concept is evaluated using the Monte Carlo method.
Materials: 6 and 12 MeV electron beams of 0.1 cm FWHM incident upon thetarget were modelled in BEAMnrc and DOSXYZnrc (EGSnrc). Under FFF
conditions, the flattening filter was omitted, and for 12 MeV the graphite layer
thickness beneath the target was enhanced for additional electron absorption. Under DSF conditions, a 1 mm steel base plate below the graphite layer
supported an axis-centered narrow steel cone filter formed like a bullet. Steelwas also used to reinforce the inner surface of the primary collimator. Photon spectra, depth dose curves and transversal dose profiles were compared
between the classical FF and the FFF and DSF configurations. The neutron
source strength was modelled by assessing photoneutron production at all
tungsten surfaces hit by photons, assuming their total absorption and using
the macroscopic photoneutron cross section.

S 420D OSE MEASUREMENT : SMALL AND COMPOSITE FIELDS AND FLATTENING FREE

D OSE MEASUREMENT : SMALL AND COMPOSITE FIELDS AND FLATTENING FREE

Results: Under FFF and DSF conditions, the number of primary electrons/Gy
at 10 cm water phantom depth is reduced by factors 2 and 1.7 (6 MeV) and
4 and 2.5 (12 MeV) respectively, indicating the corresponding reduction inbeam head photon leakage dose. The source strength of photoneutrons produced/Gy at 12 MeV is reduced by factors of 3.5 and 2.8 for the FFF and DSF
conditions respectively. Up to 1.5 times reduction in PD was achieved under
DSF conditions. Photon spectra for FFF and DSF are somewhat less filteredcompared to FF, depth dose curves are very similar, and, for side lengths up
to 10 cm, profile flatness for DSF is close to ideal.
Conclusions: The newly-designed DSF system is midway between the classical FF and the FFF linacs. It has been shown that the loss of dose profile
flattening inherent with FFF conditions can be partly compensated by the
new DSF concept, i.e. by the direction-selective photon attenuation in a smallbullet-shaped steel filter. Flattened photon beams up to 10 cm side length
are achieved at all depths, while the advantages characteristic for FFF conditions, the dose-rate enhancement, the reduction of photon and neutron leakage from the beam head/Gy in the treatment volume, and the reduction of thenormalized dose levels in the periphery are maintained. DSF conditions willsave treatment time compared to FFF.
1126 poster
APPLICATION OF A RECENTLY PROPOSED MONTE CARLO BASEDSMALL FIELD DOSIMETRY FORMALISM FOR A COMPREHENSIVESET OF DIODE DETECTORS
G. Cranmer-Sargison1 2 , S. Weston3 2 , N. Sidhu1 4 , D. I. Thwaites3 2
1

S ASKATOON C ANCER C ENTRE, Saskatoon, Saskatchewan, Canada
U NIVERSITY OF L EEDS, Leeds, United Kingdom
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom
4
U NIVERSITY OF S ASKATCHEWAN, Saskatoon, Canada

2
3

Purpose: The accuracy associated with small field dosimetry is tied to experimental conditions which include detector selection and set-up uncertainties.
However, as Alfonso et al (Med. Phys. (11), 5179-86) indicate, the accuracy
may be more intimately tied to replacement correction factors obtained using
Monte Carlo simulation and, as such, propose a new dosimetry formalism.
The goal of this work was to rigorously apply the newly proposed small field
dosimetry formalism for a comprehensive set of diode detectors.
Materials: We use Varian 6 MV jaw collimated small field sizes of 0.5, 0.6,
0.7, 0.8, 0.9, 1.0 and 3.0 cm throughout this study. Initial linac modelling was
performed with electron source parameters at 6.0, 6.1 and 6.2 MeV with theGaussian FWHM decreased in steps of 0.010 cm from 0.150 to 0.100 cm.
DOSXYZnrc simulations were run and profile data extracted for comparison
to experiment. DOSRZnrc was used to develop models of the IBA stereotactic field diode (SFD) as well as the PTW T60008, T60016 and T60017
field diodes. Simulations were run and isocentric output factors calculated
at depths of 1.5, 5.0 and 10.0 cm. This was performed using the following
source parameter subset: 6.1 and 6.2 MeV with a FWHM = 0.100, 0.110 and
0.120 cm. The source parameters were finalized by comparing experimental
OFs with simulation. OFs in water were then simulated and the replacement
correction factors calculated according the newly proposed formalism.
Results: In all cases the experimental field size width (at the 50% level)
was found to be smaller than the nominal and therefore the simulated fieldsizes were adjusted accordingly. At a FWHM = 0.150 cm simulation produced
penumbral widths that were much too broad. The fit became progressively
better as the FWHM was decreased, yet for all but the smallest field size
got worse at a FWHM = 0.100 cm. At both 6.1 and 6.2 MeV the simulated
OFs were found to be greater than, equivalent to and less than experiment
for spot size FWHM = 0.100, 0.110 and 0.120 cm respectively. This is dueto the change in source occlusion as a function of FWHM at the smallest
field size. With the source parameters finalized, the replacement correction
factors were calculated. The corrections required for the 0.5 cm field size
were 0.95 (± 1.5%) for the SFD and T60017 diodes and 0.90 (± 1.5%) for
the T60008 and T60016 diodes - indicating measured OFs to be 5% and
10% high respectfully. Our results also revealed the correction factors to bestatistically equivalent at all depths.
Conclusions: Two general conclusions come out of working through the proposed small field dosimetry formalism; (1) small field OFs are very sensitive
to the simulated source parameters and therefore rigorous linac model commissioning must be pursued prior to applying this new formalism and (2) the
corrections required for diode detectors are design dependent and therefore
complete detector modelling is required and should not be assumed as a chipin water only.
1127 poster
CHARACTERIZATION OF THE RESPONSE OF ACTIVE AND PASSIVE DETECTORS USED FOR DOSE DETERMINATION IN SMALL
PHOTON BEAMS.
S. Derreumaux1 , C. Bassinet1 , C. Huet1 , M. Chea2 , G. Boisserie2 , G.
Brunet3 , M. Baumann1 , F. Trompier1 , P. Roch1 , I. Clairand1
1
IRSN, Radiological Protection and Human Health Division, Fontenay-aux-

Roses cedex, France
2
G ROUPE H OSPITALIER P ITIE S ALPETRIERE, Department of Radiotherapy,
Paris, France
3
C ENTRE R ENÉ G AUDUCHEAU, Department of Physics, Saint-Herblain,
FrancePurpose: One of the present challenges of medical dosimetry is the accurate determination of absorbed dose in small photon beams, especially forstereotactic radiation therapy. Indeed, high dose gradient, lack of lateral electronic equilibrium and variation of photons and secondary electrons energy
spectra with beam sizes require special performances of the detectors: highresolution, tissue-equivalence, high precision. Moreover, they should exhibit
linear response as a function of the dose and of the dose rate, reproducibility
and small drift of the response during measurements. The purpose of thisstudy is to characterize the response of active and passive detectors used for
dosimetry in small beams.
Materials: Measurements were performed with active detectors dedicated tothe dosimetry in small fields (high resolution diodes: IBA SFD, Sun Nuclear
EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 0.015 cm3
PinPoint chamber, PTW 31018 microLion liquid chamber and PTW 60003
natural diamond) and with passive dosemeters suitable for small fields (TLD
micro-cubes, EBT2 Gafchromic films). They were irradiated in a Cobalt 60
beam for investigation of reproducibility and drift and for study of the response
as a function of the dose, in X-ray linac beam for study of the response as afunction of the dose rate, in X-ray linac beams of 4, 6, 10 and 18 MV for studyof the response as a function of the beam energy, and in small and large 6 MV
X-ray beams (Novalis and Varian 2100 C linac with m3 microMLC) for studyof the influence of beam size. For irradiation in Cobalt 60 beam, the detectors
were placed in air in electronic equilibrium conditions. For irradiation in X-ray
linac beams, the active detectors and the passive dosemeters were placed ina water phantom and in solid water-equivalent phantom, respectively.
Results: Regarding the reproducibility of the detector response, the diodes
give the best results, especially the EDGE and the PTW 60016 diodes withreproducibilities better than 0.3%. The SFD diode reveals serious problem ofstability, with sudden unexplainable large drift of the response (several percents).The detectors showing the highest variation of the response as a function of beam energy are the unshielded diodes, with for instance a decreaseof the response of 5% between 4 MV and 18 MV for the PTW 60017 diode.
On the contrary, the shielded diodes (PTW 60016 and EDGE) reveal more
important impact of their non tissue equivalent composition on the measurement of OF in small fields.
Conclusions: This study will help to determine an optimized methodology
for the measurement of the data characterizing the small photon beams usedin radiotherapy, in particular the output factors.
1128 poster
COLLIMATOR ANGLE AND LESION VOLUME RELATIONSHIP IN
LIVER LESION HYPO-FRACTIONATED RADIOTHERAPY WITH
FLATTENING FILTER AND FLATTENING FILTER FREE MODALITY
G. Reggiori1 , P. Mancosu1 , F. Lobefalo1 , M. Cantone2 , A. Fogliata3 , S.
Castiglioni1 , P. Navarria1 , E. Infusino1 , L. Cozzi3 , M. Scorsetti1
I STITUTO C LINICO H UMANITAS, Department of Radiation Oncology,
Rozzano (Milan), Italy
2
U NIVERSITÀ DEGLI S TUDI DI M ILANO, Department of Medical Physics andRadiation Safety, Milano, Italy
3
O NCOLOGY I NSTITUTE OF S OUTHERN S WITZERLAND, Medical Physics
Unit, Bellinzona, Switzerland

For large volumes, with fields that get near 10x10cm, there seems to be a descending trend with results that get close for the two techniques: 100.7±0.1%
and 100.6±0.5% in PTV CI and 101.±0.95% and 102.2±0.6% in HT meandose for 0◦ 45◦ respectively. MU are on the average higher for FFF plans
and for 45◦ collimator position: 5349±455 (45◦ ) and 5104±751 (0◦ ) for
FFF plans, 4925±626 (45◦ ) and 4862±724 (0◦ ) for FF plans. The beamon time was obviously higher for FF plans: 8.1±1.2min and 8.2±1min for 0◦
and 45◦ respectively; for FFF BOT resulted 2.1±0.3min and 2.2±0.2min.

Conclusions: The higher deviations shown by the 45◦ plans show that thesecollimator position, even though generally gives good results, in some cases
can give much worse results than other collimator positions: this means thatthe operator has an important role also in the choice of the optimal collimator position according to the specific patient anatomy. Surely, for the volume
region in which FFF seems better, the 45◦ position strengthens the optimality of the FFF solution. FFF technique seems to be better for intermediate
volumes though the descending trend observed in large volumes has to befurther investigated and a theoretical study is being set to do this.

1

Purpose: To compare Flattening Filter Free (FFF) and Flattening Filter (FF)modalities for variable lesion volumes and investigate, in this context, the roleof the collimator position. Meta-hepatic patients subject to hypo-fractionatedRT were considered.
Materials: Twelve patients with liver metastases with PTV volumes between 20 and 202cc were retrospectively considered. The PTV was as
CTV+5mm, the Healthy Tissue was defined as the PTV+5mm (inner wall)and PTV+15mm (outer wall). Fifty-two plans were optimized with RapidArc
technique with two different collimator angles: 45◦ and ≈10◦ for both FF
and FFF modalities and for each patient. Plans were normalised at PTV
mean dose of 75 Gy (25 Gy/3 fractions). Plans were evaluated in terms of:
CTV mean dose, HT mean dose and PTV Conformity Index (CI = body V95%
divided for PTV V95%), for each of these parameters the percentage ratio(FF/FFF)*100 was calculated. The patients were divided in three groups according to the volume lesion: 20 to 70 cc group1, 71 to 110 cc group2 and
111-33 cc group3.
Results: Figure1 reports the results for the three groups and two collimator positions: they are, on the average, better for the 45◦ position though
the SDs are higher for these plans.In group1 the data don’t show significant
differences between the two techniques, with FF/FFF values = 100.5±0.3%
and 99.9±1.12% for PTV CI (10◦ and 45◦ respectively); 101.3±0.3% and101.4±0.96% for HT mean dose (10◦ and 45◦ respectively); these differences appear in group2 with slightly better results obtained with the FFF technique: 101±0.9% and 101.7±1.5% for PTV CI (10◦ and 45◦ respectively);
101.9±0.5% and 102.6±1.2% for HT mean dose (10◦ and 45◦ respectively).

1129 poster
DETERMINATION OF OUTPUT FACTORS FOR A NOVALISSTEREOTACTIC SYSTEM USING SEVERAL ACTIVE AND PASSIVEDOSEMETERS
C. Bassinet1 , C. Huet1 , S. Derreumaux1 , G. Brunet2 , M. BAUMANN1 , P.
ROCH1 , F. Trompier1
1
I NSTITUT DE R ADIOPROTECTION ET DE S ÛRETÉ N UCLÉAIRE, Fontenayaux-Roses, France
2
C ENTRE DE L UTTE C ONTRE LE C ANCER N ANTES ATLANTIQUE R ENÉ
G AUDUCHEAU, Saint-Herblain, France
Purpose: Relative output factors require accurate determination for the useof small fields in radiotherapy techniques, especially for stereotactic treatments. The aim of this work is to determine small fields output factors withdifferent types of active detectors and passive dosemeters for a BrainLAB
Novalis stereotactic radiosurgery system equipped with m3 microMLC andcircular cones.
Materials: Output factor measurements were performed in a water phantom with commercially available active detectors dedicated to measurementsin small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW
60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW
31018 microLion liquid chamber and PTW 60003 natural diamond) and ina virtual water phantom with passive dosemeters (TLD micro-cubes, EBT2
Gafchromic films). Small field sizes were defined either by micro MLC down
to 6X6 mm or by circular cones down to 4 mm in diameter.
Results: This study shows significant differences between the results obtained by the different dosimetric systems, particularly for the smallest fieldsize for wich the difference of the measured output factors can reach 20%.
Some of these differences can be explained with the detector characteristics(detector size, tissue equivalence...).

S 421

Conclusions: These results confirm the difficulty of making accurate dose
measurements for small beams. The perspective of this study is to propose
a methodology for the determination of correction factors for the Novalis system.
1130 poster
DETERMINATION OF OUTPUT FACTORS OF A CYBERKNIFE
SYSTEM USING ACTIVE AND PASSIVE DOSEMETERS AND A
MONTE CARLO METHOD.
C. Huet1 , C. Bassinet1 , S. Derreumaux1 , M. Baumann1 , T. Lacornerie2 , F.
Trompier1 , P. Roch1 , I. Clairand1
1
I NSTITUT DE R ADIOPROTECTION ET DE S ÛRETÉ N UCLÉAIRE, Fontenayaux-Roses, France
2
C ENTRE O SCAR L AMBRET, Lille, France
Purpose: The evolution of technology in radiation therapy has allowed totreat small and irregular lesions. Three type of systems are used in stereotactic therapy and surgery (adapted or dedicated linacs equipped with circularcollimators or micro-multileaf collimators, Cyberknife and Gamma Knife) andthe smalllest field size ranges from 4 mm to 5 mm which leads to high dose
gradients and a lack of lateral electron equilibrium. Thus, the measurementof output factors (OF) of the smallest beams is very problematic and OF measurements with different detectors for similar irradiation conditions can leadto a deviation up to 30% (Derreumaux et al., 2010). The aim of this study is
to measure the OF of a Cyberknife using different active and passive detectors and to determine correction factors for active detectors thanks to a recent
methodology based on Monte Carlo data (Francescon et al., 2008 and 2009).
Materials: Output factors were measured on a Cyberknife for the 5, 7.5, 10,
20 and 60 mm diameter field sizes using commercially active detectors (highresolution diodes (IBA SFD, PTW 60016, PTW 60017, Sun Nuclear EDGE),
PTW 31014 0.015 cm3 Pinpoint chamber and PTW 60003 natural diamond)and passive dosemeters (EBT2 radiochromic films and TLD micro-cubes).
Correction factors for diodes (EDGE, PTW 60016, PTW 60017) and for the
PTW 31014 chamber were calculated folowing the Francescon’s methodology.
Results: For the smallest fiels size (5 mm diameter), a deviation of nearly
20% was observed between the smallest and the highest values of the OF
measured with the different detectors. Correction factors were applied to themeasured values for diodes (EDGE, PTW 60016, PTW 60017) and for the
PTW 31014 chamber and after correction, the OF values obtained with theactive detectors agreed within 2% with the passive OF measurements.
Conclusions: This multidetector study is encouraging concerning the determination of the smallest beams output factors of the Cyberknife. The use ofcorrection factors improves the accuracy in the output factors measurements.
Future work will be focused on the Monte Carlo modelling of the Cyberknife
system used in this study.
1131 poster
DOSIMETRIC CHARACTERISATION OF SMALL RADIOTHERAPYPHOTON FIELDS: MICRO LIQUID-FILLED IONIZATION CHAMBERCOMPARED WITH CONVENTIONAL DETECTORS
S. Andreoli1 , P. Colleoni1 , M. Fortunato1 , R. Moretti1 , M. Galelli2 , S. Ren
Kaiser2
1
O SPEDALI R IUNITI DI B ERGAMO, Fisica Sanitaria, Bergamo, Italy
2
F ONDAZIONE P OLIAMBULANZA, Fisica Sanitaria, Brescia, Italy
Purpose: Advances in radiation treatment with beamlets-based intensity
modulation and with multileaf collimating system (MLC) have resulted in theuse of small photon treatment fields. Compared to traditional radiotherapy,
this new approach can results in significant uncertainty in the accuracy ofclinical dosimetry. The dosimetric characterisation of small photon fields istime consuming, error prone and requires measurements to be made withspecialized detectors. This dosimetry is challenging due to nonequilibrium
conditions created as a consequence of secondary electron track lengths, further complicated by the prolonged electron trucks in presence of low density
inhomogeneities.This work is aimed to present the preliminary results of thedosimetric intercomparison between a micro liquid-filled ionization chamberand several conventional detectors for the characterisation of small radiotherapy photon fields. Due to the used materials and the lower measuring volume,
this micro chamber could be potentially reteined the standard detector for thischaracterisation.
Materials: These measurements were performed on 6 and 15 MV beams
delivered by a Varian Clinac DHX and an Elekta Precise, equiped with MLC.
A variety of PTW detectors were employed in a motorized water phantom(MP3, PTW): a micro liquid-filled ionization chamber, two vented ionizationchamber, a natural diamond and a diode. Moreover, gafchromic films wereinserted in a water equivalent slab phantom. For all the detectors (as listed),
Output Factors, Percentual-Depht Dose and dose profiles at different dephts
have been measured, from 1x1 to 10x10 cm2 square fields and for some
MLC conformed photon fields down to 1 cm2 . The dipendence of detectors
response on field sizes and dephts, the edge field and out-field profiles wereS 422

D OSE VOLUME PARAMETERS AND OUTCOME STUDIESD OSE MEASUREMENT : SMALL AND COMPOSITE FIELDS AND FLATTENING FREE

compared and related to micro liquid-filled chamber response.

1133 poster
EVALUATION OF 4.0 MM CONICAL COLLIMATOR OUTPUT FACTORFOR STEREOTACTIC RADIOSURGERY BEAMS
D. Zucca Aparicio1 , J. García Ruiz-Zorrilla1 , P. Fernandez-Leton1 , J. M.
Perez Moreno1 , A. Minambres1
H OSPITAL U NIVERSITARIO M ADRID S ANCHINARRO - G RUPO H OSPITAL DE
M ADRID, Servicio de Radiofísica y Protección Radiológica, Madrid, Spain

1

Results: When a detector was used in small fields, the dose-volume effectcaused an underestime of the central axis dose and a broadening of dose
profiles. This effect, for area fields lower than 15 cm2 , caused a significative
difference between OF, PDD and dose profiles (penumbra) of conventional
detectors respect to micro liquid-filled chamber. These deviations were been
higher than the lower is the area of field.
Conclusions: The dosimetry of small photon fields is drammatically constrained by the absence of lateral in-field charged particle equilibrium andby the presence of the detector (volume effect). The gafchromic films overcame the perturbation effect of detector size, but are an off-line system andthere are some problems on handling and of dose reproducibility. The microliquid-filled ionization chamber is easy to use in a water phantom and could
be the standard detector for dosimetric characterisation of small and MLC
conformed photon fields, lower than 15 cm2 . However, further dosimetric assessments are needed to validate this assumption.
1132 poster
EPID BASED CALIBRATION OF MLC LEAVES FOR A FILTER FREE
LINAC
M. Ramtohul1 , J. Cashmore1
1
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Department of Medical Physics and Radiation Safety, Birmingham, United Kingdom
Purpose: Accurate calibration of the field defining jaws and MLCs is essential for the delivery of photon beams in radiotherapy, especially for IMRT.
Standard software packages are available to perform these calibrations using
images captured by the EPID. There is an increasing use of flattening filter
free machines for IMRT delivery, and with the changes in beam profile andtransimission for these beams it is essential that calibration procedures for
un-flattened beams are developed to provide an equivalent calibration.
Materials: An Elekta Precise linear accelerator operating at 6MV has beenused for the study. The linac can operate in the conventional ’flattened’ mode
as well as ’un-flattened’ modes and are energy-matched on the central axis.
Calibration images were captured using the IViewGT EPID and analysed using AutoCAL software (V 2.0, Scanditronix Wellhfer), utilising its associatedphantom. Different gain calibrations were tested; (a) specific flattened and unflattened calibrations and (b) a common calibration generated by passing theflattened beam through 10cm of solid water. The test procedures were thenrun to calibrate MLC leaves and backup diaphragms using both the steepest
gradient and intensity measures for finding field edges.
Results: The steepest gradient method for finding field edges provides themost consistent results independent of the way in which the EPID is calibrated(<0.5 mm). Local and global intensity measures provide good agreement tofield sizes provided the gain calibration of the EPID is specific to the beam delivered. A common calibration of the EPID requires different thresholds for theintensity based measures for different field sizes to produce the same calibration values for flattened and un-flattened beams. Global intensity measures
are strongly affected by gradients in the un-flattened beams when measuring the minor gains and offsets. Calibrations produced by steepest gradientand local intensity measures for calibrating the minor gains and offsets aredifferent and need correlating to produce the correct adjustments.
Conclusions: The AutoCAL calibration software provides an accurate
method for calibrating the both jaws and MLCs for a filter free Elekta Precise
linac. The EPID calibration effects the MLC calibration obtained, however as
the gradients of the penumbra are much sharper than the gradients acrossthe beam, the effects are small. By choosing appropriate measures to find thefield edges, a single MLC calibration suitable for both flat and unflat beams
can be obtained.

Purpose: Dose Characterization for narrow beams is complicated due to thefinite size of the radiation detector, loss of lateral electronic equilibrium andthe setup of the radiation measuring equipment.A large degree of uncertainty
arises when output factors are measured for this situation, although relative
dosimetry was performed with high resolution diode detectors or film measurements.
Materials: A scanning beam/scanning chamber method has been used toovercome the limitation/difficulty of using a relatively large detector in narrow beam output factor measurementfollowing method described in the literature by J. Fan et al (Med Phys, Nov 2009). For the scanning chamber
method, multiple narrow beams are used for the dose measurement using afinite size chamber. These multiple scanning beams form an equivalent large
uniform field which provides lateral electron equilibrium condition. After themeasurement, the contributions from neighbouring beams are deconvolved
and the value is used for output factor determinations.The output factors determined in such a method has been obtained with pin-point PTW 31014 andsemiflex PTW 31010 ion chambers and compared to direct measurement
by diode and radiochromic film as described by the BrainLAB Physics Reference Guide and with direct measurement by pin-point PTW 31014 and planeparalel PTW 34001 convolving by the detector size.The contribution factor ofeach single beam is derived from the beam profile and the off-axis distanceaccurately measured by diode PTW 60012 and PTW MP3 water tank with ascan resolution of 0.1 mm (SSD 98.5 cm and depth of 1.5 cm) and for thescanning chamber method with a scan resolution of 2.5 mm for point to point
measurements.Radiochromic film dosimetry was else performed to obtain thecontribution factors as for diode detector having a good agreement for bothdose profiles except for outer zone because of the inaccuracy for lower dosevalues of the dose calibration curve for Gafchromic EBT2ROI analysis was
performed by defining a 2 px, 5 px and 10 px ROI diameter for the centerregion of each film (100 dpi scan resolution) and getting as the proper value
the 5 px ROI because of uncertainties about center placing for each ROI
Results: The following table summarizes the results obtained for the different
output factor determination

Conclusions: From the results presented above, large discrepancies areobserved between methods performed. Due to high resolution properties
for diode detector and lower dependence on processing analysis as for radiochromic film output factor from PTW 60012 has been accepted for dosimetric issues.

Results: Correction factors for msr fields for NE2571, NE2611 and Exradin
A1SL ionization chambers at the units considered in this study (TomoTherapy, CyberKnife, GammaKnife and multileaf collimated fields) were all close
to, and in most cases not significantly different from, unity. Values of about
1% higher than unity for Farmer type chambers in flattening-filter-free units
could be attributed to volume averaging effects in the centrally peaked beamprofiles. For a number of pcsr fields at different units characterised by a uniform dose region encompassing the ionization chamber, the correction factors
were also found to be unity within the measurement uncertainties. For boththe NE2571 and Exradin A1SL, data were consistent over all units and pcsr
fields and the weighted mean values were 0.997 ± 0.012 and 0.996 ± 0.012(k = 2), respectively. The application of correction factors for field output factors obtained by unit-specific methods or by volume averaging calculations
leads to better consistency between a range of detector types.
Conclusions: Review of literature data indicates that for well-designed msr
and pcsr fields, correction factors with respect to conventional reference fields
are unity within the uncertainties and that acceptably adequate correction
factors can be established for field output factors.
1. R Alfonso et al. A new formalism for reference dosimetry of small andnonstandard fields, Med Phys 35 (2008) 5179-5186

1135 poster
SURFACE DOSE CHARACTERISTICS OF 6 AND 10MV FLATTENEDAND UNFLATTENED PHOTON BEAMS
J. Cashmore1
1
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Radiotherapy Dept, Birmingham, United Kingdom
Purpose: As the use of linear accelerators operating in flattening filter freemodes becomes more wide-spread it is important to have an understandingof the surface doses delivered to patients under these conditions. Having
dosimetric data to describe the surface dose and buildup regions under arange of conditions for these beams is important if clinical decisions are to be
made.
Materials: An Elekta Precise linac with standard MLC head has been commissioned to run at 6MV and 10MV running with the flattening filter in orout. For the 6MV beam the energy has been matched to the clinical beamon the central axis (D10). The 10MV beam energy has not been adjusted
and therefore has a relatively softer beam spectrum. The flattening filter inboth cases is replaced by a thin aluminium filter to provide sufficient build-up
into the ionisation chamber. A thin window parallel plate chamber has beenused to measure a comprehensive set of data in the buildup region for thesebeams for variations in field size and SSD, and for the presence of attenuators(wedge, shadow tray and treatment couch).
Results: At 6MV surface dose measurements (measured as fractional surface dose relative to Dmax) are universally lower for unflattened beams (by up
to 10% for fields >30cm). This is repeated in the presence of both the wedge,
shadow tray and treatment couch. Only small differences (<0.5%) are seen
on varying SSD. For the 10MV beam the situation is more complicated with across-over in dose at mid to large field sizes. FSDs are generally higher (upto 10%) for the unflattened beam at smaller field sizes (<30cm open, <10cm
wedged) at this energy.

S 423

expected by the introduction of flattening filter free delivery at 6MV. At 10MV
differences in surface dose may be due to the lower effective energy of thebeam compared to the standard, but still only vary from conventional by amaximum difference of 10%.
1136 poster
THE INFLUENCE OF SPECTRAL CHANGES IN NON-REFERENCE
CONDITIONS ON STOPPING POWER RATIOS IN SMALL-FIELDDOSIMETRY
M. Taylor12 , T. Kairn3 , T. Kron21 , L. Dunn1 , R. Franich1
1
RMIT U NIVERSITY, Applied Physics, Melbourne, Australia
2
P ETER M AC C ALLUM C ANCER C ENTRE, East Melbourne, Australia
3
P REMION, Physics, Albion, Australia
Purpose: Stopping power ratios in dosimetry protocols, acquired underbroad-beam conditions, may be of questionable applicability in small-field
treatments such as stereotactic radiotherapy. Typically, a reference field of
10 x 10 cm2 is used and it is assumed that the difference in secondary electron spectrum under different conditions is negligible. However, although it isanticipated to be small, there is nonetheless a field size dependent change
in spectrum that will influence absorbed dose calculations undertaken with
an ionisation chamber. It is the objective of the present study to quantify themagnitude of the systematic error that is induced by this assumption.
Materials: The EGSnrc Monte Carlo radiation transport code was used toconstruct a dosimetrically-matched model of a Varian 600C linear accelerator
with mounted BrainLAB mini-multileaf collimator. Stopping power ratios were
calculated for field sizes ranging from 6 x 6 mm2 up to the maximum (98 x 98
mm2 ) and differences between these and the reference field were computed.
Results: Discrepancies increased with decreasing field size and increasing
depth, but remained a fraction of a percent for all field sizes studied. However,for dosimetry outside the primary field, errors induced by the assumption ofinvariant electron spectra can exceed 1 %, increasing with field size.

1134 poster
REVIEW OF CORRECTION FACTORS FOR REFERENCE DOSIMETRY OF SMALL AND COMPOSITE FIELDS
H. Palmans1
1
N ATIONAL P HYSICAL L ABORATORY, Teddington, United Kingdom
Purpose: A formalism for reference dosimetry of small and composite fields
was published [1] that will form the basis of new codes of practice under development by an international IAEA/AAPM working group. It introduces theconcepts of machine specific reference (msr ) fields for static small fields andplan-class specific reference (pcsr ) fields for composite fields. The application of both routes requires correction factors for any reference dosimetry
detectors in those fields. Also in the definition of field output factors the needfor detector specific correction factors has been introduced explicitly.
Materials: Published data have been reviewed to extract ionization chamberand diode correction factors for msr and pcsr field dosimetry with respect toa conventional reference field and for field output factors by comparing their
response with that of suitable reference detectors. In one case direct comparison with a water calorimeter was available. In other studies the reference
detectors were alanine, radiochromic film, diamond or liquid ion chambers. In
a few cases no comparison in a reference field was available and the correction factors were derived by knowledge or assumption of a different traceability route for the reference field. From many studies presenting data on field
output factors, only ratios of correction factors between two types of detectors
could be derived.

FIGURE CAPTION: Demonstrates increasing differences in the mean stopping power ratio (which affects calculations of absorbed dose) with increasing
depth and decreasing field size (compared to reference conditions). The differences are small and for many applications may be negligible.
Conclusions: The uncertainty of clinical dosimetry associated with radiotherapy techniques (such as stereotactic or intensity modulated radiotherapy) that
employ small beam segments, is greater than with conventional radiotherapy.
It is verified that the assumption of unchanging electron spectra with varying
field sizes is generally justifiable when performing (typical) in-field dosimetryof stereotactic fields. However, clinicians and physicists should be aware ofmore significant field size dependent discrepancies that arise when undertaking out-of-field dosimetry.

Conclusions: By removing the flattening filter a source of contaminationelectrons is swapped for a source of low energy photons (as these are nolonger attenuated). In practice the loss of one component seems to almost
balance with the introduction of the other. At both 6 and 10MV the filter freebeams show far less variation with field size (and in the presence of attenuators) than conventional beams.No significant effects on surface dose are

Dose Volume parameters and outcome studies

S 4241137 poster
A DOSIMETRIC COMPARISON TO FIND THE MOST OPTIMUMTECHNIQUE OF RADIOTHERAPY IN BREAST CONSERVATION
S. Patkar1 , A. Munshi2
1
I NTERNATIONAL O NCOLOGY S ERVICES P VT. LTD., medical physics andradiation safety, mumbai, India
2
TATA M EMORIAL H OSPITAL, Radiation Oncology, Mumbai, India
Purpose: In recognition of the technical limitations of traditional radiotherapy(RT) in providing a uniform and conformal dose, three-dimensional (3D) treatment planning and intensity modulated RT have been used for improvementin dosimetry and clinical outcomes. This study aims at improving target dose
distribution and avoiding unnecessary normal tissue irradiation during wholebreast RT delivery.
Materials: 8 patients of Carcinoma breast with left sided lesions were taken
for this study. CT-scans were obtained in the supine position on breast-board.
Conventional simulation was used to generate tangential beam geometry.
Treatment plans were make using four different techniques (1) 2 tangential
beams with physical wedges (PW) (2) Enhance dynamic wedge (EDW) plan,(3) 3D intensity modulation using Electronic tissue compensator (ETC) and(4)volume based intensity modulation using 6 beams (IMRT). In IMRT, couch
was rotated to 100 and 3500 to obtain 4 more complimentary tangential fields.
The prescribed dose was 50Gy in 25 fractions and was normalized such that95% volume of target was covered by 100% of prescription dose. Eclipse
planning system with analytical anisotropic algorithms was used for dose calculation. Overall dose homogeneity and normal tissue doses were assessed.
Results: Overall dose homogeneity increased with the use of ETC or IMRT
over PW or EDW for all patients. The mean dose heterogeneity for PW and
EDW was 17.7 and 18.1 respectively. This was reduced to 13.3 for ETC and12.5 for IMRT.ETC and IMRT improved the dose heterogeneity exclusively
at superior-inferior region of target volume to 2.0% and 3.2% respectively
over conventional physical wedge technique. With EDW, the total monitor
units (MUs) were least and comparable to open field technique. For IMRT,
the required MUs increased 3-times compared to open field technique. The
normal tissue doses are as shown in table.

with ductal cancer in situ. In Accelerated Patial Breast Irradiation the radiationdose is delivered within and surrounding tumor site over 4-5 days instead ofsix weeks of conventional external beam therapy to the entire breast. In thisstudy, we analysed the treatment plans of both High Dose Rate Brachytherapy and External Beam Radiotherapy based on Dose-Volume parameters foreight patients receiving radiation dose in Accelerated Patial Breast Irradiation
techinque.
Materials: Computed Tomography imagesof Eight patients undergoing APBI
were used for the treatment planning procedure. In Interstitial implant planning, the Planning Target Volume (PTV) is defined as the lumpectomy cavity
with a 2cm margin,modified anteriorly to 5mm deep to skin surface and also
along pectoral muscle. Dwell positions in each catheter implanted are activated that fall within the PTV along with some additional margin. Catheters
are reconstructed in the axial CT images. The prescribed dose (34Gy in 10
fractions over 5 days)was manually optimized .In the external beam technique, two simple conformal radiation beams were used. Wedges were
employed to modify the beam.The dose prescibed for this techinque was
30Gy in 5 fractions in alternate days.Dose Volume Histograms (DVH) weregenerated for each patient plan. The dose volume parameters such as
V100,V95,V150,V200,D100 are extracted from the DVHs generated. The
dose volume parameters are computed from the DVH data.
Results: The dose uniformity within the PTV was mwasured using the Dose
Homogeneity Index. It was found to be more than 0.85 in External beam
radiation therapy technique where it was aroung 0.71 in the case of Interstitial implant. In terms of conformality of dose distribution, XRT (External
3DCRT technique )scored well around 0.97 compared to Brachytherapy technique which was in the range of 0.50 to 0.85.More equidistant implant yielded
lesses high dose volumes which was almost negligible in three dimentional
conformal radiation therapy.
Conclusions: From the study, we found that Breast conservation can be
more effective with Three dimentional Conformal radiation External Beamtechnique compared to High Dose Rate Interstitial Brachy therapy in termsof dosimetric parameter analysis. The patient discomfort during the invasive
procedure of needle implant can also be eliminated. External beam therapy
using conformal beams can improve the cosmesis in early stage Breast cancer patients.
1139 poster

With ETC & IMRT, prescription dose spillage averaged over eight patients
could be reduced by 0.45 & 0.36 times respectively compared to conventional
physical wedge technique. Soft-tissue volume irradiated by low-dose (50%
isodose) is also shown for comparison.

Conclusions: 3D optimization using ETC or IMRT improves the overall dose
homogeneity. 3D intensity modulation using ETC or IMRT gives more conformal dose distribution. However, IMRT requires large number of MUs. ETC
seems to be simple technique for more homogenous dose distribution implying better cosmic results and reducing doses to normal tissues especiallyheart.
1138 poster
ACCELERATED PARTIAL BREAST IRRADIATION USING EXTERNAL
BEAM AND BRACHY THERAPY PLANNING: A DOSE VOLUMEANALYSIS
S. Anbumani1 , S. Palanisamy1 , R. Bilimagga1 , A. Nambi Raj2
1
2

D OSE VOLUME PARAMETERS AND OUTCOME STUDIESD OSE VOLUME PARAMETERS AND OUTCOME STUDIESB ANGALORE I NSTITUTE OF O NCOLOGY, Radiotherapy, Bangalore, India
VIT U NIVERSITY, School of Advanced Sciences

Purpose: Breast consevation therapy is accepted widely as a treatment option for most women with early stage invasive breast cancer and most patients

ASYMPTOMATIC HEART DISEASE AFTER MEDIASTINAL IRRADIATION IN HODGKIN’S LYMPHOMA: PRELIMINARY FINDINGS
G. Torre1 , M. Conson1 , R. Liuzzi2 1 , M. Caterino1 , N. De Rosa1 , L.
Camera1 , M. Picardi3 , F. Grimaldi3 , R. Solla2 1 , A. Farella1 , M. Salvatore1 ,R. Pacelli1 2 , L. Cella2 1
1
U NIVERSITY "F EDERICO II", Dipartimento di Diagnostica per Immagini eRadioterapia„ Naples, Italy
2
C ONSIGLIO N AZIONALE DELLE R ICERCHE (CNR), Istituto di Biostrutture e
Bioimmagini, Napoli, Italy
3
U NIVERSITY "F EDERICO II", Dipartimento di Ematologia, Naples, Italy
Purpose: Mediastinal irradiation in Hodgkin’s lymphoma (HL) patients is
known to cause clinically-significant heart disease with a reported cumulative incidence rates of cardiac events of 2.2%, 4.5%, 9.6% and 16% at 5-,10-, 15- and 20- years, respectively. However the occurrence of asymptomatic heart disease and the action level before symptoms development
are unknown. The purpose of this study is to evaluate radioinduced asymptomatic heart disease (AHD) through echocardiographic assessment, to analyze the eventual association with later clinical significant toxicity and to identify dose/volume constraints that correlate with AHD in HL patients treatedwith three-dimensional radiotherapy (RT).
Materials: Thirty-three patients treated by antiblastic chemotherapy (CHT)
and involved field radiation treatment (median dose 32 Gy, range 30-36) for
HL were retrospectively analyzed. Their median age was 28 years (range
17-51). Cardiac evaluation (CE), including electrocardiography and echocardiography, was performed before CHT, after CHT, and periodically after RT.
Patients with cardiac alterations at pretreatment evaluation were excluded
from the analysis. Dosimetric factors were calculated from the dose-volume
histogram for the whole heart (WH) and for specific cardiac substructures,
namely right and left ventricle (RV and LV) and for right and left atrium (RAand LA) outlined on axial computed tomography used for treatment planning.
For the aforementioned structures the following dosimetric factors where considered: percentage of volume exceeding 5-30 Gy in increment of 5 Gy (Vx),
Dmin, Dmax, and Dmean. Statistical analysis was performed using non parametric Man-Whitney’s U test.
Results: Three out of 33 patients were excluded from the analysis for preexisting abnormal finding at the echocardiography. At a median follow upof 52 months (range 23 - 99) after treatment there were not significant alterations of the ejection fraction, while 33% (10/30) developed heart valve
disorders : 27% (8/30) developed mitral valve regurgitation (VR), 3% (1/30)
developed aortic VR, and 3 % (1/30) tricuspid VR. From our analysis there
was no significant difference in the distribution of dosimetric parameters for
WH between patients who developed heart valve disorders and those whohave not. Respect to heart substructures, only LA V25 resulted significantly
associated with mitral VR.
Conclusions: Our preliminary findings suggest LA V25 as a possible predic-

tor of asymptomatic alteration of mitral valve functionality. However a longer
follow up to assess clinical significant cardiac toxicity of mediastinal irradiationfor HL and eventually associated dosimetric factors, is warranted.
1140 poster
COULD THE BAD EFFECT OF THERAPY DEPEND ON THE
PROSTATE MOVEMENTS DURING IRRADIATION ?
H. Urbanczyk1 , L. Hawrylewicz2 , L. Misztal2 , I. Wesolowska2 , W.
Majewski1 , J. Ciechowicz3 , K. Slosarek2 , L. Miszczyk1
MSC M EMORIAL C ANCER C ENTER AND I NSTITUTE OF O NCOLOGY,
G LIWICE B RANCH, Radiation Therapy Department, Gliwice, Poland
2
MSC M EMORIAL C ANCER C ENTER AND I NSTITUTE OF O NCOLOGY,
G LIWICE B RANCH, Treatment Planning Department, Gliwice, Poland
3
M EDICAL UNIVERCITY, Computer Laboratory
1

Purpose: Prostate could change localization during fractionated irradiation.
We want to estimate the displacements of prostate position during radiotherapy and we want to check if the effect of therapy depend on those displacements.
Materials: The study is based on 40 patients treated with radical radiotherapy
for localized prostate cancers between October 2004 and May 2006. Thermoplastic Orfit masks and Orfit HP System Leg Support and Foot Support
were used. The PTVs included prostates with reasonable margins. All patients were treated conformally, using high energy photons. The total dose
was 74 Gy, delivered in 37 fractions, 7.5 weeks. The positions of prostate
were evaluated once a week using CT scans. CTs, all planning procedures
and irradiation were performed using the same positioning system. Prostates
were delineated and the changes in their positions were measured using appropriate device the ’Eclipse’ program. All procedures were performed by
the same experienced two radiation oncologists and three radiation technologists. The patients have been observed after therapy every 3 months for the
first two years after treatment and every 6 months for next years.Kolmogorow
Smirnov Lilieforse, Student, U Mann Whitney and χ2/Yates tests was used
for statistical analysis.
Results: We observed major prostate displacements first of all in anteriorposterior (AP) axis. The mean of prostate movement in AP axis was 4.6 mm
and ranged between 0.0 mm and 30.1 mm. We find that only 19 (47,5%) patients had all measured displacements smaller than 10 mm. Displacements
larger than 20 mm were observed in 5 patients (12.5%). Three patients died29, 32 and 32 months after treatment without recurrence. 37 patients are being observed still. Median follow-up was 56 months. We have found biochemical relapse in 5 patients (12.5%), all of whom had major displacements: twoof them had the largest prostate displacement (median 14.0 and 12.1 mm)
and the third one had the fourth largest displacements (median 11.9 mm),the fourth one had the eight largest displacements (median 7.5 mm) and thelat one with the sixteenth one (median 4.6) mm. We have found statisticallysignificant difference between displacements of patients with and without biochemical relapse at measures from the 3rd to the last week and of course
median of all measures. We have found only one patient with clinical relapse(bone metastases) 53 months after treatment. He was the men with mediandisplacements 4.6 but his prostate’s displacements ranged from 0 to 11 mm.
Conclusions: Prostate displacements seem to be the main reason of biochemical relapse in analyzed group.
1141 poster
HOW MUCH LUNG IS IN THE FIELD? A COMPARISON OF LUNG
DEPTH MEASURED IN DRRS OF BREAST TANGENTIAL FIELDSWITH THE CORRESPONDING VOLUME OF LUNG RECEIVING HIGHDOSES IN THE DVHS OF CT PLANNED CA BREAST PATIENTS
K. Walsh1 , H. Kerr1 , J. Pettingell1 , M. Robb1 , N. McAndrew1 , B. Mzenda1 ,P. Peters1 , S. Razaq1 , A. Eve1
1
C ANCER PARTNERS UK, London, United Kingdom
Purpose: In breast radiotherapy it is sometimes necessary to reduce fieldborders, and hence dose coverage, in order to reduce the volume of lungreceiving high doses from the treatment. Traditionally the decision has been
based on the "centimetres of lung in the field", measured on the Simulator
field. Whilst this method provides an estimate of the absolute volume of lungreceiving high doses, it may not be a good indicator of the overall percentageof the lung receiving these doses. Although many centres have progressed
to 3D planning of breast treatments on CT data sets there can still be a tendency to rely on lung depth in the field, now measured in DRRs, to inform
decisions on whether to reduce field borders. Although this is the ’tried andtested’ method it would seem more sensible to look at the DVH of the lung todetermine whether the amount of lung receiving high doses is acceptable ornot, and so this study seeks to compare these two methods to determine if
there is a correlation between the two.
Materials: At our centre all breast tangent treatments are CT planned andtreated using either a conventional wedge technique or a forward planned
IMRT technique. The lungs are contoured in the CT dataset enabling us todetermine the distance of lung within the field observed in the DRRs and also

S 425

to compute the DVHs for these patients.
Results: Data from 30 patients is being compiled and the correlation between
depth of lung in the DRR and volume of lung receiving high doses will bepresented. Other factors which may affect the correlation, such as the size ofthe patient, will also be considered.
Conclusions: Due to the large variation of patient size, lung shape and total lung volume it seems likely that the traditional 2D method of determining
lung dose will be sub-optimal in some patients when the full 3D dataset andhence DVH information is available. Before moving on however it is important to establish the link between the tried and tested dose reporting methods
and the new methods available to us with the advancement in 3D planningtechnology.
1142 poster
NEURAL STEM CELL SPARING IN INTENSITY MODULATED RADIOTHERAPY OF BRAIN TUMORS: COMPUTATIONAL PLATFORM FOR
EVALUATION OF PHYSICAL &BIOLOGICAL DOSE METRICS
A. Jaganathan1 , R. Phansekar1 , R. Panta2 , M. Tiwari1 , N. Huilgol1
1

D R .B ALABHAI N ANAVATI H OSPITAL, Advanced centre for Radiation
Oncology, Mumbai, India
2
U NIVERSITY OF H EIDELBERG, Department of Medical Physics, Heidelberg,
Germany
Purpose: Neurocognitive deficits following whole brain radiation & partial radiation can cause considerable morbidity.Sparing of neural stem cells(NSC)
has been proposed as an avenue for reducing the radiation induced damage.A subjective study was performed to study the extent of NSC sparing in Intensity Modulated Radiation Therapy (IMRT) of glioblastoma multiforms(GBM).The present work aims to study the maximum sparing of
NSC,describes acute effects on stem cells and delayed sequelae to brain
following therapeutic radiation.A tool to modulate various physical and biological indices has been used to study optimization of radiation therapy for GBM
with constraints imposed on total radiation to NSC.
Materials: Ten patients of primary brain tumors who had undergone total ornear Excision of the tumors and had variable histology. They were subjected
to Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) fusion for contouring. computational codes are used to analyze the efficacyof the plan by means of Quality of coverage (QC), Homogeneity Index (HI),
Conformity Index (CI) & wide range of radiosensitivity parameters were evaluated by using Equivalent Uniform Dose (EUD) and Tumor Control Probability(TCP) to score the tumor control with and without sparing of NSC.The sessionof IMRT planning was grouped as Group1 with NSC as a constraint in optimization process and Group2 without including NSC as constraint in IMRT
segmentation.Plans in Group 1 & 2 were compared against multiple indicesbridged with functional database of computation model. This model functions
by utilizing Matlab 7.8.0.347 Version, Microsoft office Excel 2007 & Statistical
Analysis Software SAS (Cary, NC) to assess the Physical Dose metrics & Biological Dose Metrics.Ten patients of primary brain tumors who had undergone
total or near Excision of the tumors and had variable histology. They were
subjected to Computed Tomography (CT) and Magnetic Resonance Imaging(MRI) fusion for contouring. computational codes are used to analyze the efficacy of the plan by means of Quality of coverage (QC), Homogeneity Index(HI), Conformity Index (CI) & wide range of radiosensitivity parameters were
evaluated by using Equivalent Uniform Dose (EUD) and Tumor Control Probability (TCP) to score the tumor control with and without sparing of NSC.The
session of IMRT planning was grouped as Group1 with NSC as a constraint
in optimization process and Group2 without including NSC as constraint in
IMRT segmentation.Plans in Group 1 & 2 were compared against multiple
indices bridged with functional database of computation model. This model
functions by utilizing Matlab 7.8.0.347 Version, Microsoft office Excel 2007
& Statistical Analysis Software SAS (Cary, NC) to assess the Physical Dosemetrics & Biological Dose Metrics.The plan quality was deemed acceptableof SD of all the above indices calculated individually were within 0.3% against
Group2 plans .DVH as a input function, the plan in Group1 would undergo
reiteration till the acceptability criteria are met. The priority of constraint to
NSC from +a to a values as per the model output log files and get in to reiteration of plans in Group1 eventually are within acceptable limits as shown in
Flowchart of NSC Model from Figure1.

S 426

D OSE VOLUME PARAMETERS AND OUTCOME STUDIESD OSE VOLUME PARAMETERS AND OUTCOME STUDIES
Denham7
1
S IR C HARLES G AIRDNER H OSPITAL, Radiation Oncology, Perth, Australia
2
U NIVERSITY OF W ESTERN AUSTRALIA, School of Physics, Nedlands,
Australia
3
P ETER M AC C ALLUM C ANCER C ENTRE, Department of Physical Sciences,
East Melbourne, Australia
4
U NIVERSITY OF OTAGO, W ELLINGTON, Wellington, New Zealand
5
P ETER M AC C ALLUM C ANCER C ENTRE, Radiation Oncology, East
Melbourne, Australia
6
W ELLINGTON H OSPITAL, Wellington Blood and Cancer Centre, Wellington,
New Zealand
7
U NIVERSITY OF N EWCASTLE, Medicine, Callaghan, Australia

Results: The extracted header files of GROUP1 plans is modulated bychanging the priority values from a to +a for NSC in the optimization schemes,corresponds to the GROUP2 planning indices less than SD 0.3% .The objective of the model to figure out the output file implies the equipoise between
Group1 and Group 2 plans to elucidate the potential sparing without compromising plan quality. In this action the RTOG Indices the QCmean is 0.878& 0.883, HImean is 1.088 & 1.074, CImean is 1.146 & 1.144 and CNmean
is 0.613 & 0.611 shown in figure1.We found that the computation model are
well within the limit in terms of equipoise criteria adopted for the model.Mean
EUD in group1 is 51.47 & it is 51.60 in group2.Mean variation is 0.1% for
TCP shows agreement for the control probability for the adopted model. The
mean & maximum reduction of 12.23% & 28.33% on stem cells and 14.69%& 33.36% on late effects of brain.

Purpose: To describe the infrastructure and processes required to obtain ahigh-quality dataset for dose-volume outcomes analysis, and to describe theresulting dataset.
Materials: The RADAR (Randomised Androgen Deprivation and Radiotherapy) trial (TROG 03.04) examined combinations of 6 vs 18 months androgendeprivation with radiotherapy (3DCRT of 66 Gy to prostate with provision for
dose escalation in 4 Gy increments up to 78 Gy, or 3DCRT of 46 Gy followed
by a 19.5 Gy HDR boost). The technical implementation of 3DCRT challenged participating centres to ensure the delivery of precise and accurate
treatments and processes were established to quantify the quality of thosetreatments and the data they yielded.
Results: 1,071 participants were accrued from 24 centres across Australia
and New Zealand during 2003-2007. Several processes were put in place
to monitor radiotherapy quality:- A system for centralised review and archiveof digital plan data. Plan data was obtained, reviewed and archived for 755
participants. Most detected protocol deviations related to dose coverage andoutlining errors. Plan data was converted to digital objects stored in a queryable database for extraction of dose-volume information.- A benchmarking
study on sample patient CT data. This has enabled quantification of delineation variations.- A study to demonstrate setup accuracy, which enabled
65% of participating centres to improve their treatment delivery accuracy.A phantom-based study of dose delivery accuracy confirmed all centres delivered target dose as planned within +/- 5% and 75% within +/- 3%- Periodic review of GTV outliningAdditionally, data collected for individual participants included setup/localisation technique used, setup error estimates at
each fraction, the rectal and bladder filling protocol followed and equipmentused for treatment.
Conclusions: With the results of this exercise combined with clinical outcomes measures that were subject to rigorous quality assurance measures,a dataset is now available (minimum 36 months follow-up) of extremely highquality, with quantified treatment and reporting variations, and in a format
which will allow direct linkage of dosimetric and outcomes information for
dose-volume and radiobiological analysis. The techniques and infrastructure
thus established for the RADAR trial are forming the model for new trials inAustralasia.
1144 poster

Conclusions: The overall goal of this study is to incorporate patient-specificbiological information and plan specific indices in to multivariative analysis
platform. The current model was applied in the stem cell sparing IMRT plansfor GBM.Based on the evidence from invitro, animal and human studies which
support the hypothesis of radiation induced damage to NSC compartment.
Our results supports the recent investigator (Marsh et al) to emphasize theavoidance of NSC compartment and need to be inclusion criteria in IMRT
plans which manifest to brain’s natural ability to repair damage due to radiation exposure. The pilot study has shown that it is feasible to utilize RTOG
recommended Indices and Biological indices in planning on this platform. Extended works of this model includes more data points and tool need to modify with add-on features to analyze Patient response, neurocognitive tests,
updated scoring system like NCI common Toxicity Criteria version,clinical trials results from Multi-Institutional works has to be considered. It is howevernecessary to validate this model on a larger cohort of patients.
1143 poster
OBTAINING A HIGH QUALITY DATASET FOR DOSE/OUTCOMESANALYSIS – THE AUSTRALASIAN RADAR PROSTATE RADIOTHERAPY TRIAL
M. Ebert1 2 , A. Haworth3 , R. Kearvell1 , B. Hooton1 , S. Baker-James1 , N.
Spry1 , D. Joseph1 , S. Bydder1 , D. Lamb4 , G. Duchesne5 , J. Murray6 , J.

PREDICTORS OF LONG-TERM PEG DEPENDENCE AFTER EXCLUSIXE IMRT INCLUDING KINETIC OF ACUTE TOXICITY
C. Fiorino1 , B. Gunn2 , G. Sanguineti3
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
2
U NIVERSITY OF T EXAS M EDICAL B RANCH AT G ALVESTON, Department ofRadiation Oncology, Galveston, TX, USA
3
J OHN H OPKINS U NIVERSITY, Department of Radiation Oncology,
Baltimore, MD, USA
Purpose: Refining dose-volume modelling of long term use of percutaneousendoscopic gastrostomy (LT-PEG) after exclusive IMRT for oropharyngeal
cancer when including information regarding the kinetic of acute toxicity.
Materials: Fifty-nine consecutive patients treated at a single Institution withdifferent fractionation schemes were considered and predictors of PEG werepreviously assessed. For 53 out of 59, detailed weekly acute CTCv.2.0 scoresconcerning mucositis, dysphagia and xerostomia were prospectively registered during therapy; peak toxicity as well as average score over different
parts of the treatment and prevalence of grade 3 toxicities were included in
the analysis. For all patients a number of clinical/dosimetric factors previously found predictive of PEG dependence, including the weekly DVH of oral
mucosa and weekly mean dose of constrictors and larynx were considered.
Predictors of LT-PEG (3 months) dependence were assessed through uni andmulti-variate logistic analyses. Best acute toxicity predictors were selected bycomparing acute toxicity profiles of LT-PEG vs no LT-PEG patients.
Results: 20/53 patients needed a PEG tube during treatment and 14 of themwere LT-PEG dependent. The kinetic of acute dysphagia and mucositis (notof xerostomia) was significantly different between LT-PEG and no LT-PEG dependent patients (Anova test, p<0.001). In particular the occurrence of grade
3 mucositis at week 3 (MUC3) was the best predictor of LT-PEG dependence
at univariate analysis (OR: 15.1; 95%CI: 3.1-74, p=0.0008). A Stepwise multivariate logistic analysis showed a two-variable model including MUC3 and thefraction of oral mucosa receiving at least 9.5 Gy/week (V9.5Gy/w) as the most
predictive one (p<0.0001). A similarly high predictive value could be obtainedby substituting V9.5 Gy/w with the mean week dose to the Inferior constrictor
muscle (ICM). Importantly, all patients with V9.5Gy/w>65cc showed MUC3.
Conclusions: LT-PEG dependence is highly correlated by the early appearance of grade 3 mucositis. Combining MUC3 with dose-volume parametersconcerning oral mucosa and/or ICM well predicts the risk of LT-PEG dependence. The value of the previously suggested constraint for oral mucosa(V9.5Gy/w<60-65cc) was corroborated showing that the main cause of LTPEG seems to be the occurrence of early severe mucositis consequent to theirradiation of large fractions of oral mucosa at weekly dose around 9-10Gy.
1145 poster
RADIOBIOLOGIC CONSEQUENCES OF ATLAS IMPLEMENTATION:ANALYSIS OF A PROSPECTIVE RANDOMIZED STUDY
C. Fuller12 , D. Giantsoudi12 , P. Mavroidis3 , J. Nijkamp4 , J. Duppen4 ,C. Rasch4 , C. Thomas5 , P. Okunieff6 , W. Jones1 , L. Kachnic7 , N.
Papanikolaou12
1
CTRC @ UT HSC AT S AN A NTONIO, Radiation Oncology, San Antonio,USA
2
UT HSC AT S AN A NTONIO, Graduate Division of Radiological Sciences/
Department of Radiology, San Antonio, USA
3
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Medical
Radiation Physics, Stockholm, Sweden
4
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiotherapy, Amsterdam, Netherlands
5
O REGON H EALTH & S CIENCE U NIVERSITY, Radiation Medicine, Portland,
USA
6
U NIVERSITY OF F LORIDA, Radiation Oncology, Gainesville, FL, USA
7
B OSTON U NIVERSITY M EDICAL C ENTER AND M ASSACHUSETTS G ENERALH OSPITAL C ANCER C ENTER, Radiation Oncology
Purpose: Target volume delineation variability is a major concern for cooperative groups. We sought to ascertain the impact of a concensus guideline onpredicted tumor control probabilities.
Materials: Using representative case and target volume delineation instructions derived from a proposed IMRT rectal cancer clinical trial, gross tumor volume (GTV), and clinical target volumes (CTV) were contoured by
14 physician observers. Observers were then randomly assigned to receipt(Atlas) or non-receipt (Control) of a consensus guideline/atlas for anorectal
cancers (doi:10.1016/j.ijrobp.2008.08.070), then instructed to re-contour thesame case. Margin expansion and plan optimization were performed using
standardized parameters from the study protocol, using sequential dynamicarc IMRT. Tumor control probability (TCP) calculations were performed usinga D50 of 4170 cGy, γ = 2.2, and α/β value of 10 for all plans. The TCP valuesof both Atlas and Control cohorts were calculated for all the target volumes
in every plan iteration. Grouped Atlas/Control TCP values were comparedusing Wilcoxon rank sum test and Levene’s test of variance equality for thegrouped cohort GTV and CTV volumes.
Results: 26 paired plans were usable for analysis. Regarding the use ofatlas in the delineation of GTV, the corresponding TCP values between Atlas
and Control cohorts were not significantly different (mean±SD: 0.85±0.01
for Atlas, 0.86±0.1 for Control, p=0.2, n.s.). However, for CTV a statisticallysignificant difference in the corresponding TCP values between Atlas andControl cohorts was observed (mean±SD: 0.78±0.01 for Atlas, 0.72±0.1
for Control, p=0.02). These results are reasonable since the dose fall-off in
the ring between GTV and CTV is not significant. So, eventual deviationsin the target delineation approach do not introduce significant changes in theoverall dose distributions delivered to GTV in each given case. Consequently,
the corresponding TCP values do not change significantly either. For bothGTV (p=<0.01) and CTV (p=0.02), the atlas cohort exhibited reduced TCP
variance, which was also expected especially in the case of CTV.
Conclusions: Atlas implementation in rectal IMRT resulted in silico reduction
in variability between plans, with identifiable alteration in CTV, but not GTV
tumor control probability.
1146 poster
REMEMBERING NEGATIVE DOUBLE TROUBLE: FRACTIONATIONCORRECTION OF DVH CONSTRAINTS FOR RECTAL DOSE INHOMOGENEITY
K. Foo12
1
S YDNEY C ANCER C ENTRE , R OYAL P RINCE A LFRED H OSPITAL, Department of Radiation Oncology, Camperdown, Sydney, Australia
2
T HE U NIVERSITY OF S YDNEY, Sydney Medical School, Sydney, Australia
Purpose: Modern radiotherapy planning requires dose volume objectives fororgans at risk. This has resulted in many clinical studies reporting DVH predictors and constraints to limit toxicity in prostate RT. Withers identified thephenomenon of double trouble in heterogeneous dose distributions: in fractionated radiotherapy, increase in subvolume dose also increases dose per
fraction, resulting in biological effect greater than that of the dose itself. The
inverse is negative double trouble: decrease in subvolume dose results in biological sparing. Therefore, DVH constraints from multiphase (2Gy/fraction)

S 427

cohorts may not apply to dose-painted prostate IMRT. This study examines
published rectal DVH constraints, technique used in each study, and applies
fractionation correction to guide future trial design.
Materials: A search was done for publications about rectal dose-volume effects in prostate RT using online databases with reference/citation linking.
Publications in two recent systematic reviews were included. Included articles had to report a DVH cut point as a predictor or constraint with data froma clinical cohort. Studies were reviewed to determine: OAR definition, prescription dose, fractionation, number of treatment phases, patient numbers,
toxicity endpoints and DVH predictors/constraints. Fractions contributing toeach DVH cut point were inferred. For single phase treatments, cut points
were assumed to be irradiated over all fractions. For multi-phase treatments,
cut points up to the first dose level were calculated over that phase’s fractions alone, and similarly for other phases. Dose per fraction for each DVH
constraint was calculated. These, and the dose component of the DVH point,
were used to calculate the BED using the LQ model (α/β =3 for rectum). The
radiobiological isoeffect dose for each cut point was calculated for a hypothetical course of single phase IMRT given over 40 fractions, resulting in ’corrected’ DVH constraints.
Results: There is marked inter and intra study variation of technique: single/multi phase; prescription dose; fraction number. BED for each DVH point
was consistently less once a dose-heterogeneity fractionation correction wasapplied. The difference is small compared to the variability in reported constraints. The figure demonstrates the expected isoeffective dose-volume constraints for a hypothetical dose-painted single phase IMRT. Plotted next to theoriginal constraints, a consistent shift to the right is shown, indicating that
more lenient constraints could be used.

Conclusions: Use of evidence based DVH constraints should take into account the technique (simultaneous integrated boost vs sequential boost) used
to generate data compared to intended use. Too conservative use of constraints could forego gains from dose escalation. This is of particular importance in future trial design such as hypofractionation protocols.
1147 poster
THE CLINICAL IMPACT OF DIFFERENCES IN PHOTON DOSE
ALGORITHMS: 3DCRT AND SBRT OF LUNG TUMOURS
M. Chandrasekaran12 , V. Panettieri3 , C. Baker1 , A. E. Nahum1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Department of Physics,
Bebington, Merseyside, United Kingdom
2
U NIVERSITY OF L IVERPOOL, Directorate of Medical Imaging and Radiotherapy, Liverpool, United Kingdom
3
W ILLIAM B UCKLAND R ADIOTHERAPY C ENTRE, Department of Physics,
Melbourne, Australia
Purpose: Numerous studies have demonstrated differences between thedose calculation algorithms available in commercial Treatment Planning Systems (TPS). However, evaluation of radiotherapy solely in terms of physicaldose is not sufficient as it does not provide any information on the biologicaleffect or the clinical outcome. We investigate the clinical impact of the differences in absolute doses calculated by analytical dose calculation algorithms
for radiotherapy of lung tumours. These differences are expressed in termsof changes in Tumour Control Probability (TCP) for the tumour and Normal
Tissue Complication Probability (NTCP) for the uninvolved lung and rib.
Materials: Three clinical lung radiotherapy treatment plans were considered:
two 3DCRT plans and an SBRT plan. The 3DCRT plans consisted of a small(25 cm3 ), and a large tumour (174 cm3 ) both of which were planned with three
conformal fields with a prescription dose of 55 Gy in 20 fractions. The SBRT
plan (GTV of 1 cm3 , adjacent to a rib) was done with nine treatment fields witha prescription dose of 55 Gy in 5 fractions. The algorithms studied were, Pencil Beam Convolution (PBCEcl) and Analytical Anisotropic Algorithm (AAAEcl)

S 428E DUCATION AND TRAINING

D OSE VOLUME PARAMETERS AND OUTCOME STUDIESof the Eclipse TPS, the Collapsed Cone Convolution (CCCPin) of the Pinnacle TPS and the PBC and CCC of Masterplan TPS (denoted as PBCMP and
CCCMP respectively). 6 MV photon beams were used in all the three cases,
the treatment plans were done with the PBC algorithm of the Eclipse TPS andthe Monitor Units (MUs) obtained for each field were used to recalculate thedose with the other four algorithms. Dose Volume Histograms (DVHs) were
exported for radiobiological analysis using the Marsden TCP model (α=0.31
Gy-1 , σα=0.062, α/β =10 Gy, ρclon = 107 cm-3 ). TCP was calculated with
the GTV volume but with the DVH of either the GTV or the PTV in order toaccount approximately for tumour motion; the true TCP will lie between thesetwo values. The effect of differences in the volume of the GTV calculated by
the three TPSs was also studied, taking the Eclipse-calculated volumes as
the reference. The Lyman-Kutcher-Burman (LKB) NTCP for radiation pneumonitis (m=0.45, TD50=29.2 Gy, n=1, α/β =3 Gy) was computed. In addition,
the NTCP for the rib fracture in the SBRT plan was calculated using the logistic model (D50=49.8 Gy, γ 50=2.05, α/β =3 Gy).
Results: In all the cases the PBC algorithms yielded higher TCP values incomparison with other analytical algorithms. For the small tumour, TCP was
overestimated by 4-13% (absolute TCP) by the PBC algorithms; for the large
tumour there was a significant increase of up to 6-22%. Little difference wasobserved for the SBRT volume, but this was due the very high estimate of
TCP for this case, more SBRT volumes might need to be considered to see if
the TCP parameter predictions match the clinical observation. The absolutedifferences in the lung NTCP values were within 2%. The rib NTCP was ~23%
for all of the algorithms except for CCCMP which yielded 18.6% which needs
further investigation.

Results: Data from 67 patients was available for this study, 41 of whom reported ≥grade 2 fatigue at some point during the reporting period. Only 13
patients reported grade 3 toxicity. Using ROC analysis a number of dose levels were statistically significant for ≥grade 2 toxicity for each of the structurestested. However, only a subset of the dose levels that were statistically significant for Posterior Fossa were also significant for Posterior Fossa excluding
Brainstem. Volume constraints (see figure 1) were derived for the doses in
the range 15-40 Gy for Posterior Fossa and 5-40 Gy for Brainstem but for
doses 45-55 Gy the constraints were less than 1% of the volume in all cases
suggesting a maximum dose to reduce the risk of toxicity of around 45 Gy.
These results are supported by the results for grade 3 toxicity where only
the highest dose levels 45-55 Gy were statistically significant and again thevolume constraints were close to zero.

Conclusions: The results presented here indicate that the risk of radiationinduced acute fatigue may be reduced with a combination of volume constraints at doses up to 40 Gy and a maximum dose of around 45 Gy to the
Posterior Fossa and Brainstem. However the volume constraints derived inthis preliminary analysis require further study: they are derived from a small
sample size and no consideration has been made of confounding factors suchas opiate derived analgesics or baseline status.
Conclusions: The PBC algorithms of both the TPSs resulted in a higher
TCP than the more accurate analytical algorithms in all the three cases. The
differences in the volumes of the GTVs calculated by the TPSs do not cause
any significant differences in the TCP. Future work includes the extensionof the study to other tumour sites like head and neck, and breast, and the
addition of Monte-Carlo derived doses.
1148 poster
THE DOSE-VOLUME RESPONSE OF POSTERIOR FOSSA AND
BRAINSTEM WITH RESPECT TO ACUTE FATIGUE
S. Gulliford1 , A. Miah2 , S. Brennan3 , M. Partridge1 , K. Harrington2 , C.
Nutting2
1
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Joint Department of Physics, Sutton, United Kingdom
2
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Head and Neck Unit, Sutton, United Kingdom
3
S T L UKE ’ S H OSPITAL, Dublin, Ireland Republic ofPurpose: Although fatigue is often reported as a transient toxicity of radiotherapy, evidence is emerging that for head and neck patients fatigue may berelated to the distribution of dose received by structures in the brain. This
study explores these relationships by assessing whether dose volume constraints exist for the Posterior Fossa and Brainstem which would limit the incidence of radiation-induced fatigue.
Materials: This study used data from the PARSPORT trial, where patientswere randomised to receive either conformal or intensity-modulated radiotherapy for tumours of the oropharynx and hypopharynx. Dose-volume constraints were derived for the Posterior Fossa and Brainstem. In addition Posterior Fosssa excluding brainstem was also studied. Data on fatigue wasrecorded using CTCAE version 3 and the maximum value reported during
treatment or the following 8 weeks was used. The dose-volume constraints
were derived using Receiver Operator Curve (ROC) analysis (SPSS v18).
Firstly the range of volumes receiving specified doses (5 Gy increments up to
55 Gy) were tested to see if a statistically significant difference could be observed. ROC criteria of AUC >0.65 and p<0.05 where used. Where thesecriteria were met, analysis of the point on the ROC curve closest to theideal result produced a constraint value. This was achieved by calculating
sensitivity(1-specificity) for all available volume cut-points. Analysis was conducted separately for ≥ grade 2 toxicity and ≥grade 3 toxicity.

1149 poster
THE IMPACT OF PATIENT POSITIONING ON RADIATION DOSE TO
SMALL BOWEL IN PATIENTS WITH RECTAL CANCER
T. C. Frøseth1 , T. Strickert1 , G. Frykholm2 , R. J. Reidunsdatter3
1
S T. O LAVS U NIVERSITY H OSPITAL T RONDHEIM, Trondheim, Norway
2
S TATENS S TRALEVERN, Osteras, Norway3
S ØR -T RØNDELAG U NIVERSITY C OLLEGE , AFT, Trondheim, Norway
Purpose: Radiotherapy is a standard neo/adjuvant treatment for rectal cancer, but there is no standard concerning the most optimal treatment position.
The aim of this study was to find dose-volume relations in organs at risk
(small bowel, total bowel and bladder) for patients treated in prone or supine
position.
Materials: 91 patients receiving chemoradiotherapy for rectal cancer, mainly
preoperatively, were randomized to radiotherapy in prone or supine position.
A total dose of 50-54 Gy was given in 25-27 daily fractions of 2 Gy. Smallbowel, total bowel and bladder were contured and dose-volume-histogramsfor these organs were obtained using Oncentra Masterplan v.3.3. treatment
planning system. Dose-volume-histograms for small bowel were determinedat 5 Gy dose intervals (V5, V10, etc). Descriptive statistics and independent
samples T-test were used for analysis.
Results: Data from 82 patients were evaluable. No significant differences indoses / dose-volume relations to organs at risk between prone and supine
position were identified. However, at low dose-volumes (V5, V10), a larger
volume of small bowel was irradiated in the supine position.
Conclusions: In this study, radiation treatment of patients with rectal cancer
in prone or supine position was equal regarding dose or dose-volume relations to small bowel. The impact of larger low-dose-volumes on subjective
symptoms should be further investigated.

Education and training
1150 poster
CONCEPT AND EXAMPLE OF A SPECIALIZED PROCEDURE
CERTIFICATION PROGRAM IN RADIATION MEDICINE
D. Brown12 , P. Dunscombe12 , Y. Bayliss3 , M. Udowicz3
1
TOM B AKER C ANCER C ENTRE, Department of Medical Physics, Calgary,Alberta, Canada
2
U NIVERSITY OF C ALGARY, Department of Physics and Astronomy, Canada
3
TOM B AKER C ANCER C ENTRE, Department of Radiation Oncology,
Calgary, Alberta, Canada
Purpose: The purpose of this work was to enhance both safety and quality in the radiotherapy clinic through the implementation of a collaborative,
multidisciplinary in-house certification program for specialized procedures.
Materials: The certification program is comprised of four levels, each withan associated quiz or checklist. Adequate performance on quizzes/checklists
is a prerequisite for progression to the next level of certification. Level 1 isan introductory level, delivered entirely online and open to all staff of theclinic, which provides an overview of the specialized procedure. Level 2
builds awareness of the relevant literature and provides the opportunity forsupervised observations of the procedure, with defined objectives. Level 3
develops skills through supervised performance of the procedure, increases
depth of knowledge through focused literature reviews, and assesses essential competencies. And Level 4 is a maintenance of certification level thatentails performance of a minimum number of procedures per year and acommitment to staying abreast of developments in the literature and/or attending relevant continuing education sessions.The entire program, including
presentations, quizzes, competency checklists, and readings, is available online through Moodle®, an open-source Learning Management System. The
system hosts electronic presentations and enables automated quiz scoring
and record keeping, with advanced filters that facilitate determination of which
individuals have attained which levels of certification.
Results: To demonstrate the concept we have developed a full certification
program for our permanent seed implant prostate brachytherapy program.
The program is available through www.rtp-learning-centre.ca/moodle, andcan be accessed by creating a guest account. The online certification program has been well received by staff at our centre. Of particular value is theflexibility to access the self-study material from anywhere, and at any time.
For managers, automation of evaluation, record keeping, and record searching provides significant time savings and greatly facilitates the implementationof a specialized procedure certification program.
Conclusions: Our in-house certification program offers a unique, simple,
and flexible method of providing advanced education and training in specialized procedures to radiation medicine professionals. The program is continually being expanded to include other procedures and members of the clinicalteam.
1151 poster
ONE YEAR ADVANCED SPECIALIZATION TRAINING IN RADIATIONTHERAPY FOR RTTS IN ESTONIA
N. Tover12
1
N ORTH E STONIA M EDICAL C ENTER, Radiation therapy , Tallinn, Estonia
2
TARTU H EALTH C ARE C OLLEGE, Tartu, Estonia
Purpose: The main aim of the presentation is to give overview of the curriculum on advanced specialization training in radiation therapy for RTTs in Estonia.The joint projects purpose is to give opportunity for the 45 radiographers
to specialize in three different fields: radiotherapy, ultrasound diagnostics andnuclear medicine. One year specialization training is possible only after 3,5
years joint curriculum of basic radiology, i.e. curriculum concentrating mainly
in diagnostics and including a small volume (4,5 ECTS) of radiation therapy.
Materials: Financial support for the project was provided by number of international and domestic institutions.For development of each disciplines curriculum, a work group was organized, formed by domestic and international
specialists and experts.The development of RTT specialization training basedon ESTRO curriculum for RTTs. Curriculum was evaluated by our projects international and domestic experts.
Results: Establishment of the curriculum of one year advanced specialization
training in radiation therapy for RTTs in Estonia.Training capacity is 60 ECTS,
in which 30 ECTS are theoretical and 30 ECTS practical studies. 8 ECTS will
be covered by international lectures.The structure and modules of curriculum
will be presented.
Conclusions: Starting from February of 2011, ten RT students will begin
their studies based on this curriculum.During the coming studies the knowledge and expertise of the students will be raised, that will improve the qualityof radiotherapy.According to our experience, the preparations and the project
itself has increased the knowledge and motivation of those RTTs who participated in the project design.

S 429

1152 poster
PREPARING TO GO PAPERLESS AND ITS CLINICAL INTRODUCTION
K. Oliver1 , J. Davies1
1
C HRISTIE H OSPITAL NHS T RUST, The Christie @ Oldham, Manchester,
United Kingdom
Purpose: PurposeWith the development of the radiotherapy satellite centre,
The Christie at Oldham, a requirement to develop a fully networked IT infrastructure that enabled an efficient system of information transfer between thesatellite and main site was crucial. The concept of the satellite involved optimising clinical workload via the network whilst reducing patient transit times,
thus meeting the National Radiotherapy Advisory Group (NRAG) recommendations and ensuring an efficient and effective service. Systems required by
the Oldham satellite centre are hosted at the main Christie site, therefore network connectivity is critical. Staff competency and improved IT awarenessbecame an important part of the training programme to ensure the department was prepared to go paperless and continued professional development(CPD) was in place to provide ongoing support.
Materials: MethodsTraining programmes to progress to paperless working
were delivered from both external and internal trainers, externally this wasdelivered by application specialists. The development of the super usergroup with advanced skills and training was introduced internally. The purpose of this group was to continue training internally, ensuring consistancy
of use of the Oncology Management System (OMS) and to ensure further developments. Staff directly involved in the initial change to paperlessworking received several days of training from the application specialists directly.Radiotherapy is delivered via MOSAIQ version 1.6 (IMPAC) using Citrix XenApp. All procedures use the functionalities within MOSAIQ, such as
Escribe, Escan and photographic identification. Electronic authorisation has
been maximised within MOSAIQ and in radiotherapy planning by using Pinnacle and Webpublisher software. Imaging is completed within MOSAIQ
Viewstation allowing increased access and authorisation of images acrossall sites, thus improving workflow.Further training on the Citrix server for staff
groups directly involved in the satellite centre was facilitated by Christie IT
staff.
Results: ResultsHaving opened in March 2010, the centre became one of afew fully paperless departments in the UK, advantages can be clearly identified in increased access to electronic patient records offering greater flexibility, whilst ensuring full traceability and accountability. The investment in staff
training and ongoing CPD has ensured the success of this project.
Conclusions:
1153 poster
RAPID BUT EFFICIENT IMPLEMENTATION OF ADVANCED TECHNOLOGY IN RADIATION ONCOLOGY DEPARTMENT: A PHYSICISTPERSPECTIVE
A. Sharif1
1
A L A MAL O NCOLOGY C ENTRE, Department of Radiation Oncology(DA-30), Doha, Qatar
Purpose: The Radiation Oncology Department at Al Amal Hospital in Doha,
Qatar is the sole provider of Radiation Therapy treatment in the country. To
maintain and keep up with advanced technology, a decision was taken to
replace the current Treatment units together with Treatment Planning System(TPS) and Record and Verify (R&V) system to a single vendor solution withno disruption to the currently functioning clinic. Objective: Replacement of
two old Linacs, switchover from old R&V system to a new R&V system with
network, implementation of advanced treatment technique such as RapidArc
and changeover to a paperless environment, to train the staff and prepare thedepartment for the comprehensive QUATRO audit by IAEA without disrupting
clinical flow in a short time period.
Materials: The commissioning and clinical implementation of such a task requires a dedicated multi disciplinary team MDT) with the main effort comingfrom Physics. Due to staff resource limitations the project was planned in detail in advance and executed by two independent physicist teams (consistingof two physicists per team) to ensure all work was independently checked.
The staff training for the TPS and R&V system was carried out prior to delivery of the new equipment and training performed on the Test box delivered.The implementation and commissioning tasks were discussed and defined for each equipment. To ensure smooth running of the clinic and toprovide training on the impending change to a new TPS and R&V systema member of the physics team was made available in the clinic. The new
equipment implemented /commissioned in this transition period consisted ofa Varian Trilogy, Varian Clinac IX, Aria network/R&V system with 25 terminals,
and Eclipse planning system with 5 workstations
Results: The Radiation Oncology Department went Clinical with the Variansolution for Treatment planning and delivery within six months of Linac installation. The Treatment techniques being used are 3D CRT, forward planned
IMRT for breast using Field in Field, IMRT and Rapid Arc for prostate, Head& Neck and Brain. All the clinical procedures and protocols are rewritten
to accommodate the new equipment. The Quality Assurance Team for Ra-

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E DUCATION AND TRAINING

diation Oncology (QUATRO) of IAEA conducted a Comprehensive Audit ofRadiotherapy Practices in our centre and accredited the centre as competentcentre (formal certification is awaited)
Conclusions: It is possible to implement advanced technologies in busy clinics efficiently without compromising Quality. The main requirements are advanced planning with timelines, adequate staff training, QA equipment availability. Dedicated small teams released from the clinic who are task orientatedare vital to completion.
1154 poster
THE QUALITY OF RTT STUDENT TUTORING IN RADIATIONTHERAPY DEPARTMENT
A. T. Tero1 , A. L. Jussila2 , P. Liljamo3
1
O ULU U NIVERSITY C ENTRAL H OSPITAL, Department of Radiation
Oncology, Oys, Finland
2
O ULU U NIVERSITY OF A PPLIED S CIENCES, Oulu, Finland
3
O ULU U NIVERSITY C ENTRAL H OSPITAL, Oys, Finland
Purpose: To describe how RTT students experienced their clinical learning
environment and the supervision given by tutoring RTTs working in radiation
therapy department in Oulu University Central Hospital, Finland.
Materials: Data was collected among RTT students (n=45) by the validated
CLES evaluation scale of Clinical Learning Environment and Supervision(Saarikoski 2002) in 2009 and 2010. The electric CLES questionnaire consists of 27 items and is sub-divided into five sub-dimensions. They are 1)
department atmosphere, 2) premises of the art of radiation therapy on thedepartment, 3) leadership style of the department manager, 4) premisesof learning on the department, and 5) supervisory relationship. The subdimension of 1, 2, 4 and 5 were used in this research. The data was analysed
by descriptive statistics.
Results: The students evaluated the clinical learning environment and RTTs‘
clinical supervision as very good. "Atmosphere in the department" was supporting their learning positively. "The premises of the art of radiation therapy
on the department" and "the premises of learning on the department" indicated that students were relating the learning environment with the quality on
the art of radiation therapy and patient relationships. "Supervisory relationship" between tutoring RTTs and students was seen as an important elementin learning and growth of professionalism.
Conclusions: The study gives a valuable insight into students experiencesof their learning environment and supervision. The results offer a good basis
for continuing RTT students tutoring by the selected manners and available
resources.
1155 poster
TOWARDS CERTIFICATION OF RTTS IN ISRAEL: A FIRST COURSE
EXPERIENCE
R. Bar-Deroma1
1
R AMBAM M EDICAL C ENTER , T HE B RUCE R APPAPORT FACULTY OF
M EDICINE , T ECHNION, Department of Oncology, Haifa, Israel
Purpose: The profession of Radiotherapy Technologists (RTTs) is not officially recognized and certified in Israel. In an effort to change the current situation, the Ministry of Health (MoH) organized the first comprehensive course
for technologists already working in radiotherapy departments. The aim of
this work is to present the concept of the course and the conclusions that canbe drawn from it.
Materials: RTTs in Israel are certified Diagnostic Technologists and the majority own a BA degree. Their formal education includes all diagnostic techniques. Those wishing to work in Radiotherapy will get their training on thejob in one of the 6 main hospitals offering radiation treatments. A working
party including physicians, physicists, technologists and representatives ofthe MoH met several times to discuss the syllabus, time-frame and academic
institution responsible for the course. It was decided the course will be held
for young technologists already working in Radiotherapy. The ESTRO syllabus for RTTs was accepted as the basis of the course. A total of 300 hours,
1 day per week meeting was set as the time framework. Universities wereapproached with the above defined parameters as well as a requirement ofcooperation with one of the radiotherapy departments in the country.
Results: The Continuing Education Department from the Technion IIT and
Rambam Health Care Center were selected for the organization of the training. A total of 12 RTTs attended the course. Lecturers were chosen from different specializarions: physicians, physicists, nurses, technologists and psychologists all actively involved in medical and radiation oncology . Since theattending RTTs as well as the teachers had to left their departments once
every week, we had to solve logistical issues during the course of the program. As part of the course’s requirements, students had to take exams on
the different topics taught and to prepare and present a seminar at the endof it. Each student received a diploma which will entitle the holder to becomea certified RTT in the future.The Continuing Education Department from theTechnion IIT and Rambam Health Care Center were selected for the organization of the training. A total of 12 RTTs attended the course. Lecturers

were chosen from different specializarions: physicians, physicists, nurses,
technologists and psychologists all actively involved in medical and radiation
oncology . Since the attending RTTs as well as the teachers had to leave
their departments once every week, we had to solve logistical issues during
the course of the program. As part of the course’s requirements, students
had to take exams on the different topics taught and to prepare and present
a seminar at the end of it. Each student received a diploma which will entitle
the holder to become a certified RTT in the future.
Conclusions: Formal and informal discussions and evaluations were madeduring and after the end of the course. Although several pitfalls were found,the accepted general opinion stated by the students was that the course wasvery instructive and important. They emphazised that some of the new information acquired was readily applied in their routine work. The MoH has todecide whether to teach the same course again or to modify the way it has
been taught.
1156 poster‘THE UNIVERSITY COLLEGE LONDON HOSPITAL EXPERIENCE
OF PRECEPTORSHIP FOR NEWLY QUALIFIED RADIOGRAPHERS(NQR) TO ENSURE COMPETENCY THROUGHOUT THE RADIOTHERAPY DEPARTMENT’
K. Whittle1
1
U NIVERSITY C OLLEGE H OSPITAL L ONDON, Radiation Therapy Department, London, United Kingdom
Purpose: In the UK students become therapy radiographers through a 2-4
year under-graduate degree programme that includes academic and practical placements. The aim of this work was to use a preceptorship programme
to support and train our NQR’s to become competent members of the radiotherapy department. We defined this as ’the short term process of support and guidance offered to an individual during the first months of a newor significantly different role’ (CoR 2005). Through this programme gaps intraining and competence were highlighted for existing staff and individualised
mentoring programmes could be negotiated (SCoR, 2009). We train all ourradiographers to the same standard in all areas regardless of grade.
Materials: Staff were given a training and competency folder containing all
the department competencies. This was split into induction/preceptorshipwork and then some more specific competencies to assist with the transition
and rotation around department. They were inducted over a course of fourweeks to include all mandatory training requirements for example: CPR, manual handling and trust induction and an introduction to all of the clinical areas.
For these four weeks the NQR is supernumerary to ensure a thorough andconcentrated induction time. A more thorough departmental rotation, approximately 3 months per rotation includes placements in brachytherapy, mouldroom, pre-planning, and each treatment unit with specific competencies foreach. The educational lead acts as the mentor and arranges the training sessions, whilst maintaining the service. Specific training needs are met as staff,
rotate around the department to allow for specialist knowledge to include TBI,CBCT and DXR. A specific matrix is updated by the education lead. See
below (Fig1):

Functional imaging for RT andtreatment planning
1157 poster
AN INVESTIGATION OF THE DIFFERENCES BETWEEN LOCOREGIONAL LUNG VENTILATION ESTIMATION METHODSK. Latifi1 , W. van Elmpt2 , T. Dilling1 , C. Stevens1 , M. Stawicki2 , A. Dekker2 ,K. Forster1 , G. Zhang1
1
H. L EE M OFFIT C ANCER C ENTER, Radiation Oncology, Tampa, USA
2
MAASTRO C LINIC, Maastricht, Netherlands
Purpose: Radiation therapy currently does not consider local lung function intreatment plan optimization. Dose levels to whole lung which cause toxicity
have been reported but there have been few publications examining the importance of variance in respiration in different areas of normal lung. In order toaccomplish a deeper understanding of the dose effects on variably-ventilated
normal lung, robust ventilation imaging is required. This study investigates
the differences of two local ventilation estimation algorithms.
Materials: Image registration of the normal end expiration and inspiration
phases of simulation 4D CT images was used to correlate the voxels between
the two respiratory phases. Ventilation was calculated using the Jacobian andthe ∆V methods. The Jacobian method is a mathematical representation of
volume change that uses the first derivative of the deformation field to approximate the change in volume of voxels. The ∆V method is a direct geometricalcalculation of the volume change. Two different registration algorithms, Optical Flow [OF] and Diffeomorphic Morphons [DM], were used. 4D CTs from
10 esophageal patients were retrospectively analyzed. Differences between
the ventilation images generated by the Jacobian and ∆V methods using DM
registration were examined using voxel to voxel differences. This analysis
was repeated for OF registration method.
Results: Average difference between the ∆V and the Jacobian ventilation
with OF registration as a percentage of the maximum ventilation value was
0.51% with a range of 0.33% to 1.32% and standard deviation of 0.3%. Average difference between the ∆V and Jacobian ventilation with DM registration
was 0.41% with a range of 0.32% to 0.60% and standard deviation of 0.1%.
Overall the differences between the two ventilation methods are very small. A
small number of voxels show significant differences, but we speculate that thelarger differences were due to some image registration variances. Regionsof highest and lowest ventilation matched well with the different registration
techniques for both ventilation methods.
Conclusions: Differences of two ventilation methods were evaluated. There
were minor differences between the ventilation methods, Jacobian and ∆V,when using either of the registration algorithms, OF and DM. On average, thehighs and the lows in ventilation were more pronounced in the ∆V method
compared to the Jacobian one. However, regardless of the registration algorithm used the differences between the two ventilation methods were small,indicating reasonable agreement between them.

S 431

1159 poster
ESTIMATION AND CORRECTION OF EDDY-CURRENT INDUCEDGEOMETRICAL DISTORTIONS OF PROSTATE DWI SCANS
M. Kruis1 , M. Maas1 , M. Frantzen-Steneker1 , J. van de Kamer1 , J. J.
Sonke1 , M. van Herk1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands
Purpose: Historically, radiotherapy treatment plans were based solely on CT
data. In recent years, Magnetic Resonance (MR) techniques have been
incorporated in treatment planning. Diffusion Weighted Imaging (DWI) isa promising technique to detect dominant lesions inside the prostate eventhough image quality of these scans is often poor. DWI is very susceptible toeddy-current induced geometric distortions, causing misalignments between
the original signal and the diffusion sensitized signals. These misalignments
cause artefacts in the Apparent Diffusion Coefficient (ADC) map. In this study,
we investigate these distortions and their potential consequences for delineation for radiotherapy planning.
Materials: Six prostate cancer patients underwent a DWI scan (Philips
Achieva 3.0T), with b-values of 0 and 500 (s/mm2 ) in 6 directions using an
endorectal coil. To measure the eddy-current induced misalignments we registered the prostate in the different diffusion sensitized images with the unsensitized data. In these registered sensitized data we compensated for the
misalignments using b-spline interpolation. Subsequently, we averaged overthe sensitized images and used the result to calculate the ADC map.
Results:

1158 poster
DYNAMIC RESPIRATORY GATED FDG-PET OF LUNG CANCER FOR
RADIOTHERAPY PLANNING AND TUMOR CHARACTERIZATION
I. Skjei Knudtsen1 , J. Rødal2 , O. T. Brustugun2 , Helland2 , A. Skretting1 , E.
Malinen2
1
O SLO U NIVERSITY H OSPITAL, Interventional Centre, Oslo, Norway
2
O SLO U NIVERSITY H OSPITAL, Norwegian Radium Hospital, Oslo, Norway

Fig 1: Copy of Competency Matrix:
Results: Written and verbal feedback is asked of the NQR on completionof this process and has been largely positive. They feel supported in thetransition from student to NQR (Nisbet 2008). For the staff already in post it
was important to include them in this process if we are to ask them for theirexpertise in training the NQR. In collaboration with staff we have been able tore-write some competencies to reflect changes in practise.
Conclusions: Our preceptorship programme has proved to be successful as
our NQR are 100% competent in all aspects of the department. This is highlighted by our recruitment and retention of highly experienced and competentstaff, (Harbottle, 2006) with our attrition rate at less than 5%. The preceptorship package has led onto a more complex competency system for all staff
to participate in. Leading on from this work an achievement matrix has been
designed to locate any gaps in staff’s CPD records and this has been a direct
result of this work.

Purpose: We present a dynamic FDG-PET acquisition protocol for imagingof lung cancer for radiotherapy planning and tumor characterization.
Materials: A dynamic respiratory gated FDG-PET protocol for a Siemens Biograph 16 PET/CT scanner was set up, allowing data acquisition from thetime of FDG injection. Breath-hold respiratory gating was performed at fourintervals over a total acquisition time of one hour. Thus, the PET protocol
provides both a spatiotemporal characterization of the glucose distribution inlung tumors and motion-free images. The motion-free images enhance thedetectability and thus improves tumor delineation for radiotherapy planning.
Non-gated images relative to gated images may provide information on internal motion. As the heart most often is within the field of view, a tentativeplasma input function may be obtained directly from the images, facilitating
pharmacokinetic compartment analysis of the dynamic image data.
Results: So far, two pilot patients have been investigated with the current protocol. Compared to non-gated PET images, the gated images were sharper,
and SUVmax was higher. The dynamic image series could be subjected topharmacokinetic analysis and reduced into a set of compartmental rate constants k1, k2 and k3. Each rate constant can be physiologically interpreted,and the pharmacokinetic analysis may provide a means of improved characterization of lung tumors compared to conventional measures such as SUV.
Conclusions: The dynamic respiratory gated FDG-PET protocol is feasible, and may provide information of relevance for radiotherapy planning andfollow-up. A clinical trial is needed for assessing the true value of the imaging
protocol.

Distortions mainly occur in the phase encoding direction. In our dataset, thephase was encoded in the LR direction. We measured a mean absolute LR
displacement of 1.5mm (maximum 4.2mm). The mean displacement in the
AP direction was 0.4mm (maximum 1.9mm) and 0.3mm in the CC direction(maximum 1.2mm). Next, we compared ADC maps from the original andthe compensated data (Figure 1). Quantitative evaluation was performed by
calculating the average and the standard deviation of the ADC in a homogeneous part of the prostate. For all patients the standard deviation dropped
after compensation. On average this drop was 5.6% (range 1.6% - 8.7%),
whilst the average ADC signal increased by 1.8% (range 0% to 3.5%). This
demonstrates that false contrast created by these distortions, was reducedby the correction method.
Conclusions: Eddy currents can cause significant distortions in DWI and
thereby induce false contrast and mis-registrations. Compensation for thiseffect is beneficial when incorporating DWI data into radiotherapy planning.
1160 poster
EVALUATION OF THE PET-DATA QUANTIFICATION IN THE RADIOTHERAPY TREATMENT PLANNING SYSTEM
V. Jacob1 , R. Bundschuh2 , S. Astner2 , P. Kneschaurek2 , A. L. Grosu1
1
U NIVERSITÄTSKLINIK F REIBURG, Freiburg, Germany
2
K LINIKUM RECHTS DER I SAR , TU M ÜNCHEN, München, Germany
Purpose: Because of its ability to provide biological and functional information which can improve the target delineation and the assessment of ther-

S 432F UNCTIONAL IMAGING FOR RT AND TREATMENT PLANNING

apy response, the use of positron emission tomography (PET) for radiotherapy planning purposes has become increasingly important in the last few
years. PET offers additional information about the metabolism, physiology,
and molecular biology of the tumor tissue, improving GTV delineation by using a proper segmentation algorithm. One way to quantify the informationthat PET offers is to calculate the standardized uptake values (SUV). Thishas been integrated in the iPlan 4.0 (BrainLAB, Germany) radiotherapy treatment planning software. In this work the PET data quantification in terms of
the SUV calculation in the iPlan 4.0 software was evaluated. Comparisonswere made with the TrueD software, standardly used in the nuclear medicine.
Materials: For 10 patients with lung tumors that have received 18F-FDG
PET scan, automatic contouring with setting the SUV value threshold in both
systems has been evaluated. Volumes of interest (VOI) were delineated asVOI formed by iso-intensity value of SUV of 2.5VOI formed by iso-intensity
value of 40% of maximal SUV.In both systems, automated contouring wasused in order to define those VOIs.
Results: The relative differences in the VOIs in both software systems were
up to 10%. Volumes delineated in the iPlan software were almost always
something smaller then VOIs defined on the same way in the True D. Statistical analysis performed in PASW has shown very good correlation (correlation
coefficient 1.00) between VOIs contoured on both ways. The reason for differences between VOIs calculated lies in the different matrix size of the PET
data measured: iPlan uses original matrix size of the PET data (168x168 pixel- matrix size of the PET data used in the study, measured with the Biograph
64 TrueV PET/CT scanner) while TrueD software transfers the matrix size tomatch the CT data (512x512 pixel).
Conclusions: Integrating molecular imaging information as obtained from
PET into RT treatment planning might be highly beneficial for the patient interms of improved target volume definition and characterization. Results ofthis study indicate that the GTV delineation based on the PET data is not only
algorithm based problem, but it has also a strong system-dependent component. Although the influence of the size of the image matrix is in the literature
known problem, it is important to quantify it when PET data and different
contouring algorithms developed in the nuclear medicine are used for GTV
delineation. Evaluation of contouring algorithms and evaluation of software
used for PET quantification is a prerequisite for the safe implementation of
PET data into a radiotherapy planning.
1161 poster
FDG PET IN LOCALLY ADVANCED HEAD-AND-NECK CANCER: THE
PREDICTION VALUE OF METABOLIC TUMOUR VOLUME
E. Donini1 , A. Muraglia1 , P. Ciammella1 , N. D’Abbiero1 , M. Galeandro1 , T.
Palmieri1 , D. Ramundo1 , E. Cagni2 , A. Botti2 , M. Paiusco2 , C. Iotti1
1
A RCISPEDALE S. M ARIA N UOVA, Radiation Oncology, Reggio Emilia, Italy
2
A RCISPEDALE S. M ARIA N UOVA, Medical Physics, Reggio Emilia, Italy
Purpose: To evaluate the prognostic value of metabolic tumour volume measured on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)
imaging in patients treated with concurrent chemo-radiotherapy for locally advanced head-and-neck cancer at our institution.
Materials: Between January 2008 and April 2010, 37 patients, affected by
locally advanced head-and-neck cancer underwent PET/CT imaging before
treatment and referred for definitive chemo-radiotherapy to our Department.
The patients median age was 61 years (range 51-78 years). Of the 37 patients, 24 were men and 12 were women; 11 with stage III and 26 with stage
IV. All patients received definitive RT with Intensity Modulated Radiation Therapy technique (IMRT) combined with concurrent chemotherapy. According tostage and tumour site, 12 patients underwent neo-adjuvant chemotherapy
and then concomitant chemo-radiotherapy. The gross tumour volumes (GTV)
and clinical target volumes (CTV) were defined on CT, PET/CT and MRI images when available. Metabolic active tumour regions were delineated on
pre-treatment PET scan using a threshold intensity value corresponding to
40% of the local maximum intensity, which has been identified as a reasonable choice in phantom studies. All metabolic volumes have been delineatedby the same radiation oncologist.RT total dose was for all patients 66-69 Gy,
and was delivered with simultaneous integrated boost technique. We evaluated the association between metabolic tumour volume (MTV) and locoregional control (LRC).
Results: All patients concluded CT-RT treatment. The median follow-up was
18 months (range 7-30 months). The median MTV was 9.55 cm3 (range 2.227.7 cm3 ) for primitive tumour site (T) and 8.91 cm3 (range 0-33.64 cm3 ) for
nodal disease. At last follow-up the LCR was 86.5%. 2 pts had local failure.
3 pts had nodal recurrence and one case developed distant metastases. 3 ofthe 5 relapsed patients died of disease. Comparison of disease free patientsvs. those with any failure revealed that the mean MTV is not significantly
different (17.51 cm3 vs 17.26 cm3 ).
Conclusions: Several studies have demonstrated that [18 F]FDG uptake,as measured by the SUVmax, may predict outcomes in concurrent chemoradiotherapytreated head-and-neck cancer patients, but small series reported
a predictive role of metabolic tumour volume.Clinical outcomes seen in thiscohort of patients, in terms of LRC, are comparable to other modern single institution studies. Our preliminary results don’t confirm the predictiverole of metabolic tumour volume as suggested in previous studies, but this
could be caused by the short follow up. We will analyze the correlation

between the metabolic tumour volume and other several factors as T and
N classification, different anatomic subsites and different treatment modality (neoadjuvant chemotherapy plus chemoradiotherapy versus chemoradiotherapy). Certainly, prospective multicentric trials to confirm the reliability of
metabolic tumour volume in predicting outcome are needed.
1162 poster
FDG-PET GUIDED DOSE-PAINTING IN OROPHARYNGEAL SCC:
WHAT IS THE EFFECT OF SEGMENTATION TECHNIQUE ON
ESTIMATED TCP?
M. Lei1 2 , D. Rickard3 , J. Crawshaw4 , C. Clark3 , E. Adams3 , S. Gianolini5 ,T. Jordan3 , S. Whitaker1 , A. Nisbet6 7 , T. Guerrero Urbano1 2
1
R OYAL S URREY C OUNTY H OSPITAL, Department of Clinical Oncology,
Guildford, United Kingdom
2
U NIVERSITY OF S URREY, Postgraduate Medical School, Guildford, United
Kingdom
3
R OYAL S URREY C OUNTY H OSPITAL, Department of Radiotherapy Physics,
Guildford, United Kingdom
4
R OYAL S URREY C OUNTY H OSPITAL, Department of Radiology, Guildford,
United Kingdom
5
M EDICAL S OFTWARE S OLUTIONS G MB H, Hagendorn , Switzerland
6
R OYAL S URREY C OUNTY H OSPITAL, Department of Medical Physics,
Guildford, United Kingdom
7
U NIVERSITY OF S URREY, Faculty of Health Medical Sciences, Guildford,
United Kingdom
Purpose: Local failure following radical radiotherapy remains common in patients with localised head and neck cancer. Dose-painting with IMRT can escalate radiation dose to target volumes identified by functional imaging suchas FDG-PET and has potential to improve the therapeutic ratio. The optimal
method of FDG-PET image segmentation remains unclear. Visual interpretation by clinicians is the most common approach currently but is prone to interand intra-observer variation. We compare estimated tumour control probabilities (TCPs) for volumes generated by 5 FDG-PET segmentation techniques,
when only the volume delineated by clinicians (GTVFDGclin) has been selected for dose-painting.
Materials: FDG-PET-CT scans for 10 patients with SCC oropharynx were
imported into Eclipse v8.2 (Varian Medical Systems). Standard clinical target
volumes were delineated using departmental guidelines. The GTVFDGclin
was contoured jointly by a clinical oncologist and a nuclear medicine physician. 3 GTVFDG volumes were generated using thresholds of FDG-PET uptake: 36% of maximal signal intensity (GTVFDG36%), SUV of 2.5 (GTVFDGSUV2.5) and an adaptive threshold based on the source-to-background ratio (GTVFDGSBR). Finally, a Fuzzy Locally Adaptive Bayesian algorithm
was used (GTVFDGFLAB).Simultaneous integrated boost (SIB) IMRT wasplanned to deliver standard doses of 65Gy/30 fractions and 54Gy/30 fractions to the high dose radical PTV1 and elective PTV2, respectively. 4 doselevels (DL) relative to the PTV1 dose were dose-painted to the GTVFDGclin:
DL1 (100%), DL2 (105%), DL3 (110%) and DL4 (115%). Estimates of TCP
and NTCP were calculated using Biosuite software. Student’s t-test was used
to compare the differences in mean TCP between GTVFDG volumes, using
the GTVFDGclin as reference.
Results: The median (range) volumes (cm3 ) were as follows: GTVFDGclin
10.8 (2-81.2), GTVFDG36% 8.73 (0.87-91.5), GTVFDGSUV2.5 27.8 (2.9249.9), GTVFDGSBR 22.5 (6.1-124.7) and GTVFDGFLAB 7.8 (1.0-63.0).

Conclusions: GTVFDG36% and GTVFDGFLAB showed no statistically significant differences in mean TCP compared to GTVFDGclin, at all 4 doselevels except for GTVFDGFLAB at DL1. Therefore, delineation of a dosepainting target by these techniques appears to approximate current standard
use of visual interpretation by clinicians and could be used to improve reproducibility of results.
1163 poster
FDG-PET/CT FOR TARGET VOLUME DELINEATION IN THE
VOLUMETRIC MODULATED ARC RADIOTHERAPY IN CERVICALCANCER
R. Lazzari1 , A. Cecconi1 , V. Dell’ Acqua1 2 , A. Vavassori1 , L. L. Travaini3 ,E. Rondi4 , S. Vigorito4 , F. Cattani4 , C. Fodor1 , B. A. Jereczek-Fossa12 , R.

F UNCTIONAL IMAGING FOR RT AND TREATMENT PLANNING
Orecchia12
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Radiotherapy, Milan,
Italy
2
U NIVERSITY OF M ILAN, Milan, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Nuclear Medicine,
Milan, Italy
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Division of Medical Physics, Milan,
Italy

S 433

1164 poster
ILLUMINATION USING PULSED LED REDUCES PHOTOTOXICITY
AND PHOTOBLEACHING IN FLUORESCENCE IMAGING OF LIVING
CELLS
R. Penjweini1 , H. G.Loew12 , K. W.Kratky1
1

U NIVERSITY OF V IENNA , FACULTY OF P HYSICS , P HYSICS OF P HYSIOLOG -ICAL P ROCESSES , Physics Department, Vienna, Austria

2

Purpose: To evaluate the role of FDG-PET/CT in the staging and target volume definition in image-guided radiotherapy technique based on volumetricintensity modulated arc delivery (RA-IMRT) in cervical cancer.
Materials: From June to November 2010, 25 patients (pts) affected bycervical cancer were treated with RapidArc simultaneous integrated boost(SIB)-IMRT at the European Institute of Oncology, Milan, Italy. After standard staging with MRI, all pts underwent FDG-PET/CT in order to exclude distant metastases and to define gross tumour volume (GTV). Elevenand 14 pts received exclusive and adjuvant radiotherapy, respectively. In
all cases concomitant chemotherapy was administrated during radiotherapy. The CT and MRI TNM and FIGO stage of disease of pts was (table1):T1bN0= 4,T1bN1=6, T2bN0=5, T2aN1 = 2, T2bN1=4, T3bN1=1 ;T4N1M0=1T2bN1M1=1; T4N1M1=1; IB=4, IIB=5, IIIB=13; IVA=1; IVB=2.
All pts underwent a 3 mm simulation CT scan then integrated the volumes
definition with a FDG-PET/CT. SIB-IMRT technique was employed: 50 Gy(2 Gy/fraction) was prescribed to the T , 46-50Gy (2 Gy/fraction) to surgical T bed, 45 Gy (1.8 Gy/fraction) to N0 pelvic lymph nodes, 55 Gy (2.2
Gy/fraction) to the positive lymph nodes and 50 Gy (2 Gy/fraction) to the paraaortic lymph-nodes.For all pts the radiation treatment schedule included also
a boost of 15-30 Gy delivered with high or pulsed dose rate brachytherapy(HDR or PDR). Cone beam CT (CBCT) was performed for the first 5 days of
RapidArc-IMRT. Any variation of set-up was then controlled twice a week andthe institutional action level protocols were applied.

M EDICAL U NIVERSITY OF V IENNA , D EPARTMENT FOR T HERAPEUTICR ADIOLOGY, MEDECINE, Vienna, Austria

Purpose: Imaging of living cells, including fluorescent dyes, using sophisticated light microscopes, has received much attention in recent years due toits facilities, which offer researchers to study cellular dynamics and functions
in great detail. The technique now spans all fields of the life sciences andextends to the physical sciences as well. However, it is crucial to ensure thatthe physiological and biological processes that are under investigation are
not altered in any way during the imaging.Most cells, as part of their normallife cycle, are never exposed to light, and it is known that some light sources,
when highly focused by the microscope, can produce toxic and damage thecells (Phototoxicity). The Phototoxicity is worsened if the cells incubate withfluorescent dyes. Photoexcitation of fluorescent dyes produce reactive oxygen species that are toxic toward many live cells and accelerate beaching of
the fluorophores during the course of extended or repeated measurements(Photobleaching). Thus, for live-cell-imaging, it is best to reduce the amountof excitation light by optimizing the efficiency of the light path through the microscope, and by using detectors that are optimized to detect most of the lightemission.
Materials: We recently developed a suitable cellular environment and an illumination system using a high power blue light-emitting-diode (LED) for fluorescence microscopy. The blue LED can emit continuously or emit shortpulses of light (0.5-2 ms) to excite fluorescent dyes. To demonstrate the usefulness of the new system, we compared images of human lung epithelial
carcinoma cells (A549) proliferation incubated with carboxyfluorescein diacetate succinimidyl ester (CFSE) and PVP-hypericin fluorescent indicators andexcited with either blue LED as a continuous excitation light source or the LED
as a source of pulsed illumination with the same light intensity.
Results: We found that the proliferation of A549 cells decreased rapidly andPhotobleaching was relatively rapid under continuous illumination, whereas
under pulsed LED illumination, motility was maintained and Photobleaching
was much reduced.
Conclusions: In conclusion, fluorescence microscopy using LED-based
pulsed illumination offers significant advantages for long-term live-cellimaging, reducing the degree of Phototoxicity, and extending the effective
lifetime of fluorescent dyes.
1165 poster
IMAGING PROPERTIES OF AN ENERGY DISCRIMINATING X-RAY
DETECTOR BASED ON CDTE
T. Koenig1 , M. Zuber1 , A. Zwerger2 , A. Fauler2 , S. Nill1 , M. Fiederle2 , U.
Oelfke1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Division of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
F REIBURG M ATERIALS R ESEARCH C ENTER, Freiburg, Germany
1

Results: In 6 pts FDG-PET/CT has changed the TNM andor FIGO stage (Nor M status) of disease compared to conventional MRI staging and CT scan:particulary FDG-PET/CT imaging showed highlights metabolically active tumour in para-aortic lymph nodes and in external iliac nodes, therefore thestage was changed from M0 to M1 (FIGO IIIB vs IVB) in 5 pts and from N0 to
N1 in 1 pt respectively.PTV was always covered by 95-107% of the prescribed
dose. The mean D50% (dose received by 50% of the volume) for the bladder,
rectum and small bowel were 31.9 Gy, 39.8 Gy and 12.35 Gy, respectively. At
the mean follow-up of 2 months (range 0.5-4 months) all pts are alive and noevidence of disease, particularly the pts underwent to radical treatment arein complete remission confirmed by a conventional MRI imaging and FDGPET/CT scan.
Conclusions: Our preliminary results indicate that the FDG-PET/CT leads
to a better staging of disease and to a better volume definition and has thepotential of showing lymph-nodes metastasis not only within the pelvis but
also in the para-aortic area. In addition, with FDG-PET/CT it was possible
to definite better the target volume, therefore to reduce significantly the doseof organs at risk (OARs). This might also open the space for the escalationdose regimens.

Purpose: Photon counting pixel detectors based on semiconductor sensors
have received increased interest during the past years. In contrast to conventional multi-energy CT, they offer energy discrimination in the detector itself
rather than on the source side. The purpose of this study was to investigate
the imaging properties of a cadmium telluride (CdTe) sensor attached to a
Medipix2 Hexa readout system, i.e. we were interested in measuring the energy response function (ERF) of the sensor along with the full width at half
maximum (FWHM) of the photo-peak, the presampling modulation transfer
function (MTF) as well as the detective quantum efficiency (DQE).p { marginbottom: 0.08in; }Materials: Six Medipix2 readouts were combined to form a 3x2 detector arrayof 4.2cm x 2.8cm size. A 1 mm thick CdTe sensor was used to ensure appropriate absorption, and a pixel pitch of 165 microns was chosen to mitigate theeffects of charges and fluorescence photons shared among neighbouring pixels. The ERF of this detector was measured at bias voltages of 200, 300, 400& 500V using an 241 Am source (59.6 keV). The FWHM of the photo-peak as
well as the detective quantum efficiency at zero spatial frequency using said
source were determined. The MTF was characterised using a tilted-wedge
technique and an X-ray tube operated at 120 kVp.
Results: An energy resolution of 2.2 keV FWHM was found for bias voltagesof 400 V and above. The spectra were also observed to be significantly affected by fluorescence photons . An energy dependence of the MTF wasobserved, with the 5% level located at 5.7/mm, 7.3/mm and 9.0/mm when thelower energy threshold was set to 10, 25 or 50 keV. The MTF at the lowest
setting was found to be fluorescence limited, as it did not show any dependence on the bias voltage. The DQE was measured to be 83% at 59.6 keV.

S 434F UNCTIONAL IMAGING FOR RT AND TREATMENT PLANNING

F UNCTIONAL IMAGING FOR RT AND TREATMENT PLANNING

S 435

1169 poster
PET PARTIAL VOLUME EFFECT INFLUENCE IN MANUAL TARGET
VOLUMES DELINEATION IN EXTERNAL RADIOTHERAPY
J. Santos1 , A. Dias1 , J. Lencart1 , O. Sousa2 , F. Borges1 , A. Bastos3
1
I NSTITUTO P ORTUGUÊS DE O NCOLOGIA, Medical Physics Imaging, Porto,
Portugal
2
I NSTITUO P ORTUGUÊS O NCOLOGIA FRANCISCO G ENTIL -P ORTO, Porto,
Portugal
3
I NSTITUTO P ORTUGUÊS DE O NCOLOGIA, Nucl Med PET research, Porto,
Portugal

Conclusions: The FWHM found corresponds to a relative energy resolutionof less than 4%, but the overall energy response function is adversely affectedby the occurrence of charge sharing as well as X-ray fluorescences for a pixel
pitch of 165 microns. This pixel pitch is therefore too small to give unbiased
spectra. If quantitative results are desired, there is need for either a charge
summing logic in the readout system (which is offered by the Medipix3 platform) or an inverse filtering of the spectra in software, which can be done
when the energy response function is known over the photon energy range
of interest.

Figure 1 shows EUO as a function of both mean voxel ppOx and voxel dosedelivered in 32 fractions. If voxels with ppOx < 5 mmHg are considered hypoxic, the conversion led to increases of 10-74% in the number of hypoxic
voxels.
Conclusions: EUO can be used in conjunction with established methods toderive the optimal dose distribution from a given hypoxia image. Accounting for predicted microscopic variations in ppOx has a significant impact on
hypoxia dose painting and may allow for more accurate prediction and optimisation of treatment response.

1166 poster
IMPACT OF FUNCTIONAL CONTRAST ON NON-UNIFORM RADIOTHERAPY DOSE PRESCRIPTIONS
A. Le Maitre1 , M. Hatt1 , C. Cheze Le Rest2 1 , O. Pradier2 , D. Visvikis1
1
INSERM U650 L ATIM, Brest, France
2
CHU M ORVAN, BREST, France

1168 poster
Purpose: Tumours are heterogeneous structures and the use of functional
imaging with new radiotracers allows visualizing and quantifying these heterogeneities in terms of clonogen density, hypoxia or proliferation. In the past
few years several studies focused on how to adapt the dose prescription tothese heterogeneities in order to improve treatment outcome. One of the aspects of heterogeneity is the functional contrast and the objective of this work
is to study the impact of this contrast on two non uniform dose prescription
scenarios: the dose redistribution and the dose boosting.
Materials: The data used in this study were simulated PET images. Fivecases with two compartments within the ground-truth were considered withdifferent heterogeneity shapes and sizes. For each case six contrasts between the two compartments were considered: 1.5, 2, 2.5, 3, 5 and 8. The
same ground truth was considered to represent either FDG or FMISO uptake.
The data were then segmented using the Fuzzy Locally Adaptive Bayesian(FLAB) algorithm able to handle heterogeneous uptakes. Within the global
tumour volume the uptake was converted in biological parameters based on
previously proposed models, considering a correlation between the FDG and
FMISO uptake with clonogenic cell density and pO2 respectively. Two scenarios were considered for adapting the dose prescription to functional tumour heterogeneity, namely dose redistribution and dose boosting. The dose
redistribution was performed on a voxel by voxel basis or within the two tumour compartments defined by FLAB. One of the proposed methods is tomaximize the TCP under mean dose constraint. The TCP model used inthis work is the linear quadratic model with α normally distributed (for lungtumours, α=0.36Gy-1 , α/β =10Gy, γ =0.231day-1 σα=0.11Gy-1 ). A uniform
clinical dose of 66Gy delivered in 33 fractions was considered. For the dose
boosting three dose boosts were considered 5, 10 and 15Gy. The number offractions was kept to 33 so the fraction size in the boost volume was 2.15, 2.3
and 2.45Gy respectively. For each case and scenario the percentage TCP
increase with respect to the TCP for a uniform dose was calculated.
Results: The TCP increase resulting from a dose redistribution based on
the functional information depends on functional contrast. It remains small
for FDG cases (increase < 1.6%) but is significantly higher for FMISO (up to114%). The TCP increase is higher for the dose boosting scenario for both
FDG (up to 8% for the 5Gy boost and all contrasts) and FMISO (from 19 to
54% for the 5Gy boost and all contrasts) cases, depending on the size of the
sub-volume considered.

Conclusions: The TCP increase for both scenarios (dose redistribution anddose boosting) depends on the functional contrast (a higher functional contrast results in a higher TCP increase). The increase for both scenarios ishigher for FMISO than for FDG cases where even low contrasts (<2) lead tosignificant increase in TCP (>19% for the 5Gy dose boost).

IS HYPOXIA PET IMAGE CONTRAST ENHANCED BY FASTER
TRACER CLEARANCE? A SIMULATION STUDY
D. Moennich1 , E. Troost2 , J. Kaanders2 , W. Oyen2 , M. Alber3 , D.
Thorwarth1
1
U NIVERSITÄTSKLINIK FÜR R ADIOONKOLOGIE, Section for Biomedical
Physics, Tübingen, Germany
2
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Institute of
Oncology, Nijmegen, Netherlands
3
U NIVERSITÄTSKLINIK FÜR R ADIOONKOLOGIE, Tübingen, Germany

1167 poster
INTRODUCING THE CONCEPT OF EQUIVALENT UNIFORM OXYGENATION
C. South1 , P. Evans2 , D. Thorwarth3 , M. Partridge2
1
R OYAL M ARSDEN HOSPITAL, Joint Department of Physics, Sutton, United
Kingdom
2
I NSTITUTE OF C ANCER R ESEARCH, Joint Department of Physics, Sutton,
United Kingdom
3
U NIVERSITÄTSKLINIK FÜR R ADIOONKOLOGIE, Section for Biomedical
Physics, Tübingen, Germany
Purpose: Oxygenation is known to affect radiosensitivity, and various methods have been proposed for using functional imaging to adapt radiotherapy
treatment plans to account for spatial variations in partial pressure of oxygen (ppOx). Hypoxia is known to vary over microscopic length scales, whilst
for most functional imaging techniques resolution is fundamentally limited byvoxel size. Hypoxia dose painting methods typically take imaging signal torepresent mean voxel ppOx and use this to optimise dose distribution. However, the non-linear relationship between radiosensitivity and ppOx meansthat radiation response is likely to be dominated by the most hypoxic cells
within a voxel. We propose a method to account for predicted intra-voxel
heterogeneity when dose painting.
Materials: The linear quadratic model was used to predict the surviving fraction of cells following irradiation, accounting for spatial variations in dose andppOx. Intra-voxel oxygen distributions were predicted based on data published by Petit et al (2009), who modelled oxygen transport to predict themost likely microscopic oxygen histogram for a given mean voxel pressure.
We introduce the concept of Equivalent Uniform Oxygenation, which is theuniform ppOx in a voxel resulting in the same number of surviving cells as thepredicted microscopic oxygen distribution for a given dose. Mean and effective oxygen histograms were calculated for FMISO PET images of 3 patientswith head and neck tumours, acquired 4 hours post-injection.
Results:

Purpose: Tumour hypoxia can be assessed non-invasively by positronemission tomography (PET) using tracers such as 18 F-Fluoromisonidazole(Fmiso) that accumulate in poorly oxygenated cells. A fast clearance oftracer molecules from blood plasma is generally considered a desirable property to achieve high tumour to blood (T/B) ratios in hypoxia PET images.
The purpose of this simulation study was to investigate how hypoxia tracers with faster plasma clearance, but transport and binding properties similar
to Fmiso, affect PET image contrast.
Materials: A method was developed to simulate supply, diffusion and bindingof Fmiso based on histology-derived vessel maps. Objects on these maps
act as sources and sinks for oxygen as well as tracer molecules. Molecular
distributions in the extravascular space are determined by reaction-diffusion
equations, which are solved numerically using a two-dimensional finite element method. One important input to the method is the plasma tracer concentration, which is specified by a sum of two exponentials fitted to clinicalFmiso data measured from multiple blood samples. The first exponential
varies quickly (time constant τ =6 min) corresponding to tracer distribution
in the body while the second varies more slowly representing clearance fromplasma (τ =15.6 h). Faster clearance was simulated by decreasing the time
constant of the latter component, thus increasing the clearance rate 1/τ .
Contrast between simulated PET activity concentrations was defined as (A1A2)/(A1+A2).
Results: Tracer concentrations in regions with distinctive vessel densities 4
hours after administration were simulated for three clearance rates (original,
3-fold and 9-fold). Compared to the original clearance rate, absolute simulated signal intensities were dramatically reduced by 40% for the 3-fold increase and 87% for the 9-fold increase, which may impact the signal-to-noiselevel in PET imaging. The regional contrast against plasma background, representing T/B contrast, increased on average by 23% and 131%, respectively.
Contrast changes between distinctively vascularised regions, which may represent intratumoural contrast, were ambiguous. It decreased on average by
27% for a 3-fold increased rate but increased on average by 49% for the 9-foldincrease.
Conclusions: Contrast in hypoxia PET images might be enhanced by using
Fmiso-like tracers that are cleared from plasma faster than Fmiso. A limiting factor is that absolute signals and signal differences decrease with fasterclearance.

Purpose: External radiotherapy planning demands a manifold step process.
One of these steps involves volume description by delineating the regions
to be irradiated according international recommendations, namely Reports
ICRU 50, 62 and ICRU 83 when the treatment indication is for IntensityModulated Radiation Therapy (IMRT) [1, 2, 3]. The use of multi-imaging
acquisition system to improve the radiation treatment target delineation is aparticular example of personalised treatment. The first approach to target
volume delineation is the computed tomography image set (CT) used by thetreatment planning system. Subsidiary diagnostic images such as positronemission tomography (PET) or magnetic resonance imaging (MRI) can bealso useful to determine the disease extension and the delineation of thevolumes. Although several computational methods (e.g. computational segmentation methods) can be used for automatic volume delineation, manual
methods are still the main practice. However, this practice has the main drawback of a large variability of resulting contours according to the physician. The
purpose of this work is to try to quantify at which level the manual delineation
methodology can influence the final result.
Materials: A semi-anthropomorphic phantom was used to simulate the tumour fixation of 18-F: FDG (half-life 109 min.) as well as the background. A
Siemens Biograph 6 High-Rez was used for PET image acquisition. Tumour
18-F:FDG absorption was simulated using two cylindrical chambers (diameters 0.5 cm and 1.0 cm) with different volumes (1:4 volume ratio: 1.2 cm3 and4.7 cm3 approximately) and a time dependent but equal activity concentration, immersed in a decaying 18-F background. The tumour decay corrected
activity showed a linear FDG absorption by the tumours. Acquisitions (3Dmode, 81 axial slices) were made every 4 minutes, corresponding to different
time instants in the tracer bio-distribution. The gross target volumes (GTV)
were delineated using the PET axial images by an experienced radiation oncologist.
Results: The 1:4 ratio between the geometric chamber volumes disappearedalmost completely in the delineated GTVs on all the PET acquisitions. Nevertheless, the difference between the GTV volumes increased with time by
30% since 45 min. (1:1 ratio) to 90 min (6:8 ratio) from the initial injection
time (this period is characterized by an increasing activity in the chambers
and a decaying background). The delineated GTVs (roughly between 5 and8 cm3 ) showed also to be larger than both real chamber volumes.
Conclusions: The observed increase in the GTV volume is expected due to
PET resolution since the actual image is the PET point spread function (PSF)
convolved with the real activity distribution inside the chambers. The PSF
of PET depends on several factors and can be reasonably fit by a Gaussianfunction with a FWHM (full width at half maximum) of 4~5 mm. Partial volume
effect is then responsible for the observed results, since it relates to PET resolution. This indicates that in such small volume tumours, a special concern
must be taken into account during GTV delineation and further studies of PET
image thresholding and segmentation methodologies is mandatory. Also thetime of acquisition should be carefully considered.The observed increase in
the GTV volume is expected due to PET resolution since the actual image is
the PET point spread function (PSF) convolved with the real activity distribution inside the chambers. The PSF of PET depends on several factors andcan be reasonably fit by a Gaussian function with a FWHM (full width at half
maximum) of 4~5 mm. Partial volume effect is then responsible for the observed results, since it relates to PET resolution. This indicates that in suchsmall volume tumours, a special concern must be taken into account during
GTV delineation and further studies of PET image thresholding and segmentation methodologies is mandatory. Also the time of acquisition should be
carefully considered. References:
1. ICRU Report 50, Prescribing, recording and reporting photon beam
therapy, 1993.
2. ICRU Report 62, (Supplement to ICRU 50), 1999.
3. ICRU Report 83, Prescribing, recording and reporting photon-beam
intensity-modulated radiation therapy (IMRT), 2010.

1170 poster
QUALITY ASSURANCE PROCEDURES IN RADIOTHERAPYFUNCTIONAL MAGNETIC RESONANCE IMAGING USING IMAGEJS 436

IGRT: 4D IMAGINGF UNCTIONAL IMAGING FOR RT AND TREATMENT PLANNING

SOFTWARE
L. Cerqua1 , D. Aragno2 , E. Cotroneo3 , M. Pacilio2 , M. C. Pressello2 , R.

1171 poster

Rauco2 , E. Santini2
1
L A S APIENZA U NIVERSITY, School of Medical Physics, Rome, Italy
2
A ZIENDA O SPEDALIERA S AN C AMILLO - F ORLANINI, Medical Physics
Department , Roma, Italy
3
A ZIENDA O SPEDALIERA S AN C AMILLO - F ORLANINI, Neuroradiology,
Roma, Italy

SPECTRAL CT WITH A CDTE SEMICONDUCTOR DETECTOR
J. Schulze1 , T. Koenig1 , M. Zuber1 , A. Zwerger2 , A. Fauler2 , S. Nill1 , M.
Fiederle2 , U. Oelfke1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Division of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
F REIBURG M ATERIALS R ESEARCH C ENTER, Freiburg, Germany

Purpose: The application of functional imaging in radiotherapy is rapidly
emerging and MRI functional imaging (fMRI) may be a powerful tool for accurate delineation of macroscopic tumor, for monitoring therapeutic response
and for detection of radiation related normal tissue damage. The fMRI acquisitions are characterized as a time series where the same volume is repeatedly acquired over time. Since the BOLD signal changes related to theeffect are very small (few percent), the stability of the fMRI signal is critical.
This technique requires a robust quality assurance (QA) programme to verify
temporal signal stability. The aim of this work is to propose a convenient andquick QA procedures for the image quality and temporal stability of the signalthat can be easily used before patient images acquisition.
Materials: The fMRI acquisitions were performed with the sense head coilof a Philips Gyroscan NT 1.5 T scanner using GE-EPI sequences. The parameter of the sequences were: FOV 24 cm, TE 50 ms, TR 3000 ms, 80
time frames. A cylindrical phantom, 16 cm diameter, filled with 8 mM CuSO4
water solution was used. Only time-series data from the central slice wereused for analysis. For each time frame in the series image signal intensities
were measured using a defined set of region of interest (ROI). Three quality control (QC) parameters were assessed: Signal-to-Noise Ratio (SNR),
Non-Uniformity (NU) and Signal-to-Fluctuaction-Noise Ratio (SFNR). For theevaluation of SNR single and double image methods were used. The signal
to fluctuation noise ratio was measured in an image made from (signal mean
image)/(fluctuation noise image). Fluctuation noise image was calculated as
the standard deviation of the residuals of detrending a 2-order polynomial.
The NU was calculated using the deviation signal image. For the analysis ofthese parameters were used ImageJ plug-in specially developed.
Results: Plug-in return the images and analysis of quality control parameters.
The plug-in applications for the QC parameters has produced reproducible
results. The figure 1 shows the images obtained with the SFNR plug-in. The
SFNR value obtained was 278.

Purpose: Dual energy CT is an imaging modality that is frequently used in
medical diagnostics due to its capability to determine mean atomic numbers
and electron densities in a voxel, which are important parameters to determine the material composition and calculate stopping powers in heavy ion
radiotherapy. However, being based on the acquisition of two separate images with different tube voltages, its energy resolution, which is a crucial
parameter to determine the above quantities, is limited. In this work, we go
one step further by employing a semiconductor detector of the Medipix2 family. It is capable of energy discrimination and promises to acquire spectrally
resolved X-ray images without the need for a second X-ray tube operated at adifferent voltage. Furthermore, due to its photon counting capabilities, it offers
higher SNRs than conventional detectors. In principle, the sharing of signals
between neighbouring pixels in a photon counting detector can degrade thespectral resolution if the pixel pitch is chosen too small. In this study, we investigate whether the pixel pitch of 165 microns implemented in our detector
is large enough to detect the K-edge present in an iodine contrast agent.
Materials: A 3x2 array of Medipix2 readouts were attached to a 1mm thick
CdTe sensor, amounting to a total area of 4.2cm x 2.8cm. A CT image ofa plastic tube filled with the iodine contrast agent Imeron 300 was recorded
using a soft X-ray spectrum generated by a medical X-ray tube operated at
50 kVp with a mean photon energy of roughly 34 keV. The detector was run insingle threshold mode, i.e. it counted every event above a predefined photon
energy. The contrast agent employed exhibited an absorption edge at 33.2
keV, hence images were taken at 28, 30, 34 & 36 keV, and energy windows
were reconstructed in software at energies of 28-30, 30-32 & 34-36 keV bysubtracting the recorded images from another.
Results: A profile of the absorption coefficients along a single line of thereconstructed CT images is depicted in the figure (thick lines: windowed images; thin lines: single threshold mode images). For the energy windows
chosen, the absorption coefficients below the absorption edge can be seen
to decrease with increasing photon energy, whereas a strong increase can beobserved above the absorption edge. The curve corresponding to the highest
energy window additionally shows a comparably poor SNR due to the lack oftransmitted photons in this energy range. In the curves corresponding to thesingle threshold images, enhanced cupping due to beam hardening can beobserved. This effect is reduced in the windowed images since beam hardening naturally vanishes when the window size approaches zero.

Fig. 1: a) an image signal of time-series; b) image signal; c) fluctuation noise
image (SD detrend’s residuals); d) image SFNR
Conclusions: The development of these plug-in has detected a product suitable for carrying out evaluations of the QC parameters proposed in the literature, in a very fast time (order of few second). The plug-in developed with
ImageJ can run on any pc and the ImageJ interface is also simple and easy
to handle. This software can be run as an online applet, a downloadable
application, or on any computer with a Java or later virtual machine. Theseplug-ins are potentially useful in cases that require immediate evaluation of
the QC parameters in fMRI.

Conclusions: The pixel pitch of 165 microns was shown to be large enoughto detect the K-edge of iodine in CT images. Also, the use of energy windows
largely removes cupping artefacts due to beam hardening.
1172 poster
TESTING THE IMPACT OF MOTION BLURRING IN PET IMAGESAPPLIED TO DOSE-PAINTED IMRT PLANS IN LUNG CANCERPATIENTS
R. Perrin1 , C. South2 , S. Webb1 , M. Partridge3
1
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Joint Department of Physics, Sutton, United Kingdom
2
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Sutton, United Kingdom
3
I NSTITUTE OF C ANCER R ESEARCH, Joint Department of Physics, Sutton,
United Kingdom

Purpose: In lung cancer dose-painting with PET/CT image-guidance would
be a promising way of escalating dose to radio-resistant subvolumes, toachieve a better tumour control probability (TCP), while maintaining an acceptable dose to normal lung. However tumour motion during image acquisition degrades the signal. In this work we assign a radiobiological parameter
according to FDG-PET signal intensity. With respiratory-correlated (RC) andnon-RC PET/CT lung images we test the impact of signal degradation on
PET-image-guided IMRT plans. The endpoint tested is TCP.
Materials:

In a patient study, for which 8 patients were recruited, we acquired amplitudebinned respiratory-correlated FDG-PET/CT data using a spirometer. Two setsof patient data were included in the study (since in only 2 / 8 patients could
motion be detected). In both patient data sets the motion amplitude was 12mm peak-to-peak.Two sets of biological maps were generated assigning either clonogenic cell density (rho) or partial pressure of oxygen (pO2) to image
voxels based on the non-RC image voxel intensity. A linear relationship between voxel intensity and radiobiological parameter was used. Prescription
dose maps were then optimised for a fixed integral dose of 64 Gy in 32 fractions by maximising TCP subject to the modelled biological heterogeneity.
The dose maps were then simplified into 2 or 3 dose-level maps, without asignificant reduction in the optimal TCP obtained from the optimisation. The
quantised dose-maps were exported to Pinnacle and deliverable IMRT plans
were produced with 2- or 3- compartments (rho or pO2 respectively) that respected OAR dose constraints.The deliverable dose cubes from the Pinnacle
IMRT plan (based on the non-RC image data) were then applied to biologicalmaps for the non-RC and RC images respectively (see Fig.1). TCP was evaluated in each case using a voxel-wise calculation of survival fraction subject
to clonogen-burden or pO2. The resultant TCPs were used to evaluate theimpact of the motion-blurring artefact. The TCP for a uniform dose of 64 Gy
in 32 fractions was also calculated using the non-RC and RC biological maps
for comparison with the dose-painted planning results.
Results: Considering the precision of the biological maps between RC andnon-RC images, for the dose-painted plans only small differences in TCP (<5%) were found. This was due to only small differences in the dose prescription levels between the non-RC- and the RC-image-based plans. Considering
the general improvements in TCP gained for dose-painted plans vs uniform
dose plans, dose-painted plans based on rho maps brought no significant
difference in TCP. However for dose-painted plans with dose prescriptions
based on pO2 maps, TCP improvements compared to uniform dose plans
were around 30%.
Conclusions: Motion-blurring artefacts evaluated in the patient cases (amplitudes = 12 mm) did not significantly affect the dose-painted plan outcome.

IGRT: 4D imaging
1173 poster
4DCT COMPARISON OF TWO BREATHING SURROGATE SYSTEMSBY USING A BREATHING PHANTOM
A. Vásquez Torres1 , A. Runz1 , E. Gernot1 , G. Sroka-Perez2 , C. P. Karger1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
U NIV.
K LINIKUM H EIDELBERG, Department of Radiation Oncology,
Heidelberg, Germany

Purpose: To compare 4DCTs reconstructions made with one Raw-CTdataset but sorted with different breathing surrogate systems with help of amoving phantom.
Materials: An in-house developed anthropomorphic phantom capable of simulate respiration in a precise fashion is used. It possesses an expandable
surface and a superior-inferior moving "tumour", shaped as a sphere. BothS 437

movements are controlled by stepper motors. A trajectory shaped as a cosine curve to the power of four is used on both motors. The movement in
the anterior-posterior direction of the surface of the phantom is tracked bya stereoscopic camera system (VisionRT, VisionRT Ltd., London, UK) running a proprietary software named GateCT. The expansion of the phantom
is recorded by a stress gauge called Respiratory Gating System AZ-733V(Anzai, Tokyo, Japan), which is attached around the phantom by means ofan elastic belt.The phantom is scanned with a Somaton Sensation Open CTScanner (Siemens, Erlangen, Germany) in helical mode. While doing this,
GateCT and Anzai systems will be recording the "breathing" of the phantom.
Two 4DCTs will be reconstructed by an amplitude based sorting algorithmwith just one CT-Raw-dataset and the signal of each surrogate system.The
centroid of the visible tumour sphere was measured in 4DCT-reconstructions
at 8 different breathing phases, following an established clinical protocol.
Results: As expected the recorded breathing signals of both systems lookedrobust and in phase with each other, before the helical scanning procedure
started. During X-Ray-on time, the GateCT respiratory signal showed abaseline-drift caused by a small increasing tilt of the table as it goes into
the CT-Bore with an interplay effect of a non-perfect calibration of the system. Anzai did not show any change neither in shape nor baseline during
the CT-Scan. Measured centroid positions revealed different positions for agiven reconstructed breathing phase. Subsequent experiments showed thatthe baseline drift was not directly the cause of the found difference.
Conclusions: With help of an in-house developed anthropomorphic moving
phantom capable of simulate breathing, two different surrogate breathing systems were tested. The signals of these systems were used to reconstruct two
4DCTs and a comparison of the position of the centroid of a moving spherelocated in the phantom was made. These measurements show different positions of the centroid depending on the used respiratory signal for a selected
breathing phase. More experiments are needed to see which surrogate system represents more exactly the tumour location.
1174 poster
A STUDY ON POSITION AND VOLUME VARIATION OF TUMOR AND
ADJACENT NORMAL TISSUE DURING RESPIRATION FOR PATIENTWITH LUNG CANCER.
Z. Ying-jie1 , J. Li1
1
S HANDONG C ANCER H OSPITAL, Department of Radiation Oncology, Jinan,
China

Purpose: To investigate the correlation of position movement of primary tumor with interested organs and skin markers, and to investigate the correlation of volume variation of primary tumors and lungs during different respiration phases for patients with lung cancer at free breath condition scanned by
4D-CT simulation .
Materials: Based on simulation 4D-CT images which binned in 10 respiratory
phases, 16 patients with lung cancer were scanned at free breath condition bysimulation 4D-CT which connected to a respiration-monitoring system (RPM). A coordinate system was created based on image of T5 phase, which was
registered by other images of 9 phases. Gross tumor volumes (GTV) and normal tissue structures (lungs, hilum of lungs, tracheal bifurcation, diaphragm
top and skin markers ) of 10 phases were contoured. The three dimensional
position variation of GTVs centroid, hilum of lungs, tracheal bifurcation, diaphragm top, skin markers were measured and their correlation were analyzed, and the same for the volume variation of GTVs and lungs by 4D-CT
images of 10 respiratory phases.
Results: Movement range of lung cancer in different lobe differed extinctly: 0.8mm5.0mm in upper lobe, 5.7mm5.9mm in middle lobe and10.2mm13.7mm in lower lobe.
Movement range of lung cancer inthree dimensional direction was different: Z-axis 4.31±4.34mmY-axis
2.19±1.04mmX-axis 1.73±1.5mm. For individual patients, the range ofmaximum three-dimensional centroid movement was 0.7513.65 mm for
GTVs, 2.839.70 mm for tracheal bifurcation, 2.249.11 mm for hilum of lung,6.2125.40 mm for diaphragm top, and 0 5.5 mm for skin markers. Mean volume of GTV was 20.90cm3 range 20.25cm3 21.66 cm3 Mean volume of lungwas 2800.55cm3 range 2657.58cm3 2968.54cm3 . There was no statisticalsignificance for volume variation of tumor and lung(r=0.23, p=0.52).
Conclusions: Based on 4D-CT, statistically significant differences of GTVs
centroid movement were observed at different pulmonary lobes, and the differences of centroid movement in three dimensional directions were significant, but no significant correlation between three dimensional vector of GTVs
and that of normal tissue structures or skin markers were observed. So individual 4D-CT measurement is necessary for definition of ITV margin for lungcancer.

S 438

IGRT: 4D IMAGING

IGRT: 4D IMAGING

1175 poster
BEAM’S EYE VIEW BASED VERIFICATION OF ACTUAL DELIVERYUSING IN-TREATMENT 4D CONE-BEAM CT
K. Nakagawa1 , A. Haga2 , H. Yamashita3 , S. Kida3 , N. Saotome3 , A.
Sakumi4 , T. Imae1 , K. Ohtomo1 , Y. Masutani1 , K. Yoda5
T HE U NIVERSITY OF TOKYO H OSPITAL, Radiology, Tokyo, JapanU NIVERSITY OF TOKYO, Radiology, Tokyo, Japan3U NIVERSITY OF TOKYO, Tokyo, Japan
4
T HE U NIVERSITY OF TOKYO H OSPITAL, Tokyo, Japan
5
E LEKTA KK, Medical Physics, Kobe, Japan

1

2

Purpose: The monitoring and the record of the target motion during treatment are still an important and a challenging topic for radiation therapy. In
this paper, we present a novel verification method of actual delivery using
4D-CBCT images during volumetric modulated radiation therapy (VMAT) for
stereotactic radiation therapy (SRT).
Materials: Elekta Synergy accelerator mounting a kV-CBCT system wasused. A phase recognition technique based on a normalized cross correlation(NCC) between adjacent kV-projections was developed. The beam’s-eyeview (BEV) based single-arc VMAT-SRT treatment was created with Ergo++(Elekta) and Pinnacle (Philips) treatment planning system (TPS) with 5mm of
PTV margin and 6mm of leaf margin. The treatment was performed for 7 lungcancer patients with simultaneous irradiation of kV beams. The kV 4D-CBCT
images during treatment were reconstructed off line using in-house software.
These images were then exported to TPS and the actual delivery region wasverified with the BEV.
Results: The recognition rate of peak-inhale using present phase-recognition
technique was 100% in all cases compared to eye’s tracking. The gantryangle increment per projection for 4D-CBCT with 4-phase bins was 4.1 ±
2.2 (1SD) degrees, on average. Admittedly, there are large gaps of projections and large deviations of the gaps compared with those in ordinary CBCT
reconstruction. Nevertheless, with in-treatment 4D-CBCT images, it was possible to identify the tumor position. A phase of 4D-CBCT’s may be selected
depending on the gantry angle with the information of the respiratory signal.
Figure shows the typical example of a BEV-based verification of VMAT treatment. We confirmed that tumors newly identified by 4D-CBCT were within
BEV’s through a course of treatment in this study.

introduce a large systematic error in the treatment. It is therefore important toinvestigate the accuracy of 4D-CT scanners.The aim of this study is to identify and compare the volume and motion of a tumour in a motion phantom
imaged on different 4D-CT scanners.
Materials: A moving lung tumour was imaged using a Dynamic Thorax Phantom (CIRS model 008A) on three different 4D-CT systems: two commercial
and one in-house developed system. The scanning protocol used at eachscanner was the pre-defined clinical setups. The moving tumour was scanned
twice at each scanner with different motion amplitudes in the cranio-caudal
direction (0.0; 0.5; 1.0; 1.5; 2.0 cm) with a constant cycle time of 4s. The
4D-CT scans were divided into ten phases at the scanners and exported toa research version of Pinnacle3 (vers. 9.1) for volume and motion analysis.
Automated adaptation of an initial ideal tumour model was applied on theimaged tumour in each phase to determine the imaged volume. Also, dicecoefficients were calculated for each phase.
Results: Decent agreement is found between the observed and the actual
peak-to-peak tumour motion amplitudes with a maximum deviation of 4.7%,
8% and 10% for the two commercial 4D-CT scanners and the in-house developed system, respectively. The minimum dice coefficients are 0.89, 0.85
and 0.81.The differences between the maximum and minimum tumour volume over the individual respiration phases relative to the real volume are13%, 51%, and 58% for the different scanners. The corresponding mean coefficients of variation are 4%, 11%, and 14%. An example of the volume
variations are shown in the figure. The phases with the largest volume deviations correspond to variations in the radius of the tumour of ~0.1cm, ~0.3cm
and ~0.3cm for the three scanners. These variations introduce systematic
treatment uncertainties in the tumour definition.

1177 poster
COMPARISON OF PLANNING TARGET VOLUMES BASED ON
THREE-DIMENSIONAL CT AND FOUR-DIMENSIONAL CT SIMULATION IMAGES OF NON-SMALL-CELL LUNG CANCER
F. li1 , J. Li1 , Y. Zhang1 , T. Liu1
1
S HANDONG C ANCER H OSPITAL, Jinan, China
Purpose: To compare positional and volumetric differences of planning target
volumes (PTV) based on axial 3D-CT and 4D-CT for the primary tumor of
non-small cell lung cancer (NLCLC).
Materials: Twenty-eight patients with 16 lesions located in the upper lobe and
12 lesions in middle and lower lobes initially underwent 3D-CT scans followed
by 4D-CT scans of the thorax under normal free breathing. PTVvector was
defined the GTV contuored on 3D-CT and its motion vector: CTVs were created by adding 7 mm to GTVs, then, ITVs were produced by enlarging CTVs
isotropically based on the individually measured amount of motion in the 4DCT, lastly, PTVs were created by adding 3 mm setup margin to ITVs; PTV4D
was defined on the fusion of CTVs on all phases of the 4D data: the CTV
was generated by adding 7mm to the GTV on each phase, then, PTVs were
produced by fusing CTVs on 10 phases and adding 3 mm setup margin. The
position of the target center, the volume of target and the degree of inclusion(DI) were compared reciprocally between PTVvector and PTV4D, and the 3D
motion vector on the relative parameters were compared on the grouping.
Results: The median of the 3D motion vector for lesions in the upper lobe
and in the middle and lower lobe were 0.28cm and 0.70cm respectively. A
comparison of the target center coordinates only demonstrated significant
spatial difference in the x axe for lesions in the upper lobe (z = -2.010p =0.044), while in the z axe for lesions in the middle and lower lobe (z = 2.136p = 0.033). The median of ratio of PTV4D and PTVvector was 0.75 and0.52 respectively. A significant correlation was found for the motion vector
and the ratio of PTVvector and PTV4D in both groups (r = -0.638-0.850p <0.05). For all patients, fhe median of DI of PTV4D in PTVvector was 66.39%,
showed a significant inverse correlation with the motion vector (r = -0.814p <0.001); while the median of DI of PTVvector in PTV4D was 99.55%, showed
a positive significant correlation with the motion vector (r = 0.613p = 0.001).
Conclusions: The amplitude of tumor motion in the middle and lower lobe
is larger than that in the upper lobe. The location of PTVvector and PTV4D
demonstrate a significant difference in some a direction. PTV4D is smaller
than PTVvector, the ratio of PTV4D and PTVvector is correlated to motion
vector of the tumor. As the amplitude of tumor motion increases, the DI
of PTVvector in PTV4D increases, while the DI of PTV4D in PTVvector decreases.
1178 poster
EVALUATION OF THE EFFECT OF TUMOUR BED MARKER
MOVEMENT UPON PATIENT SET-UP ACCURACY DURING BREAST
RADIOTHERAPY
E. Harris1 , E. Donovan2 , C. Coles3 , S. Eagle4 , A. Kirby5 , P. Evans1
1
I NSTITUTE OF C ANCER R ESEARCH, Joint Department of Physics, Sutton,
United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Joint Department of
Physics, Sutton, United Kingdom
3
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Department of Oncology, Cambridge, United Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiotherapy Department, Sutton, United Kingdom
5
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of
Oncology, Sutton, United Kingdom

Conclusions: Our phase-recognition technique provided a high performance. Also we showed that it was feasible to verify the tumor position during
actual delivery by using in-treatment 4D-CBCT with VMAT treatment. Since
the present 4D-CBCT technique does not provide a real-time respiratory motion, but an "averaged" one over the treatment, further consideration will be
required for a real verification.
1176 poster
COMPARISON OF IMAGED TUMOUR VOLUME FROM DIFFERENT
4D-CT SCANNERS USING A MOTION PHANTOM
T. B. Nielsen1 2 , C. R. Hansen2 , O. Hansen1 3 , C. Brink1 2
1
U NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark
2
O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
Denmark
3
O DENSE U NIVERSITY H OSPITAL, Department of Radiation Oncology,
Odense, Denmark
Purpose: In treatment planning a 4D-CT scan is performed to reduce artefacts from respiratory motion and selection of mid-ventilation phase. Different
4D-CT scanners are based on different techniques to generate the images.
However, for all of them it is vital that the tumour shape and position are imaged as accurate as possible. Otherwise, the definition of the tumour may

Conclusions: The volume differences between the ten phases add an additional uncertainty to the definition of the tumour and introduce systematic
errors in the treatment. The volume in the phases corresponding to the outermost positions of the tumour (phase 1 and 6) seems to image the volume
close to the real volume. It seems that the mid-ventilation phase which is
associated to phases with the largest tumour velocity, is often related to thephases with large deviation of the imaged volume. It is important to validate
and if possible optimise the scanning protocol of 4D-CT scanners in order tominimise artefacts in the images used to define the tumour shape and position.

Purpose: Patients taking part in the NCRI IMPORT HIGH trial have six clips
inserted into the tumour bed (one at the chest wall, one at the superficial
margin of excision and one at each of the superior, inferior, lateral and medial margins of excision) in order to localise the breast boost target volume.
During a course of radiotherapy (RT) clip movement may occur and someclips may exhibit more stability than others. The aim of this work is to determine the day-to-day variation of individual clip positions and how this willaffect treatment set-up accuracy and impact on planning target volume (PTV)
margins.
Materials: This study includes a sub-set of 13 IMPORT HIGH breast cancer
patients treated at Sutton, who all had six tumour bed (TB) clips and CBCT
imaging for set-up on a varying number of treatment days (5-11). Two patientswere observed to have seroma. Using Elekta XVI software individual clip positions were extracted after both bony anatomy matching and clip matching to
the reference CT. Translational and rotational shifts and the distance of individual clips from their centre of mass (COM) were recorded. Displacements
away from the COM are positive and those towards the COM are negative.
Association of the magnitude and variation (two standard deviations) of motion with TB size, breast size, TB position and clip position was investigated.
Results: The chest wall clip was the most stable in 4 of the 13 patients analysed, no other clip was stable in more than two patients. The mean variationof clip position during treatment was less than 4mm with the exception of
one patient for whom one clip migrated a substantial distance of 25mm. The

S 439

mean clip displacement relative to the COM of the markers was between 0
and 2.5mm for 10 patients. For one patient a large positive (up to 20mm)
displacement of the clips was observed due to swelling and two patients hadlarge negative displacements due to shrinkage of seroma. Correlation (0.73,
p-value = 0.004) between average clip displacement and TB size was observed. This association was not observed if the two patients with seroma
were removed from the analysis. No association between breast size, TB
position or clip position and clip movement (displacement and variation) was
observed.
Conclusions: For this small group of patients the chest wall clip was themost stable. The largest clip displacements were observed in patients withseroma. Positive mean clip, displacement illustrating clips moving away fromthe COM, of up to 2.5mm, and variation of displacement of up to 4mm inpatients with no seroma suggests that tumour bed deformation needs to be
included in the calculation of PTV margins. Data are available for a further 48
patients and these will be used to confirm these findings.
1179 poster
EVALUATION OF THE MOTION OF AN INTERNAL VOLUME BY
MEANS SIGNALS SURROGATE ACQUIRED USING OPTICAL
TRACKING DEVICES
G. Guidi1 , G. Mistretta2 , L. Binotti3 , L. Boni1 , F. Bertoni3 , T. Costi1
1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Medical Physics, Modena,
Italy
2
U NIVERSITY OF B OLOGNA, Medical Physics, Bologna, Italy
3
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Radiation Oncology,
Modena, Italy
Purpose: The aim of this study is to determine whether the use of external
breathing surrogate signals (eg, skin or surface skin marker), acquired by optical tracking systems, can relate the movement of internal organs and allow
a correct assessment of the volumes. We have tested and quantified if there
are any parameters or constraints, relative to the size of detector, which canaffect the correct size of the internal volume and therefore volume contours,
and if they may introduce unexpected distortions.
Materials: To simplify the complex problem, we have identified a signal sinusoidal steady with 15bpm. The signal was simulated by a phantom (Quasar)with inserted containing a known cubic volume (27cm3). Were performed
eleven 4DCT retrospective scans by a CT Large Bore (Toshiba) and simultaneously acquired the respiratory signal through optical system (VisionRT).
We have used different detector option acquisition (0.5mm, 1mm, 2mm) for
the triplets of examinations, while all other scan parameters remained constant for each study, such kVp, mAs, FOV, reconstruction thickness (2mm)and scan rotation time (0.5s). Three scans were performed, without reconstruction and three with 4D mode. The signal is ever triggered with the CT at
15bpm. Finally, it was made a rotation and translation of the phantom in orderto create a movement of the center of mass from previous exams. In the lasttwo scans were acquired one with the cube placed in the lower midline of thephantom (Caudal) and the second acquisition was located in the upper midline (Cranial), to show that by tracking systems and an absence of adequate
external imaging systems, even in the presence of respiratory signs identical,
the surrogate signals are not representative of the spatial position of the internal volume. To not introduce errors by the operator, we have identified a
unique threshold for all examinations from which volume and center of mass
were extrapolated.
Results: By comparing the volume and center of mass obtained with andwithout 4DCT reconstruction, there are small deformations and possible under or overestimation of volumes using automated methods. In the case exams without 4D reconstruction, the volume has a variable affected by errorsof about 5%, while in the case of 4D studies, this is a function of phase bin.
In particular for phases 0%, 70-80-90%, the error is less than 4%. The useof 4D reconstruction techniques allows a partial recovery of the deformationof volumes, inside each phase bin, with an minimum improvement of 1-2% inphases of expiration. No evident correlation due to the size of the detector,
although with the detector size of 0.5mm, the error of the volume extrapolated
automatically is less than 1%. The motion of the center of mass with acquisitions parallel to the scanning plane and affected by roto-translation of thephantom is correlated with the respiratory sinogram. However, appear to be
identifiable stages of the prevailing stability (0,70,80,90%) to be confirmed byusing different respiratory signals.The images of the two scans with inverted
insert than the midline, have instead shown that despite the sinogram respiratory identical, the inserts and the spatial positions of the internal objects are
not correlated with the marker or the external surface of the skin without theuse of appropriate imaging.
Conclusions: The preliminary results showed that although the thresholds
defined, the automatic contouring of moving objects could be affected by significant errors in the case of small volumes. The functions of the motionsof the centers of mass are not dependent on the size of the detector. The
surrogate signals must be related to the exact spatial position and size ofthe internal target, only by using an adequate imaging. The external surrogate detected by optical systems are stable and reproducible tools and how
to trigger scanning equipment and 4DCT, but could have some bias without
an accurate inspection of the images.

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IGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIESIGRT: 4D IMAGING

1180 poster
EVALUATION OF VIEW INTERPOLATION ALGORITHMS TO IMPROVE 4D-CBCT IMAGE QUALITY
H. Zhang1 , J. J. Sonke1
1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands

Purpose: Acquisition times of 4D-CBCT scanners integrated with linear accelerators are relatively slow (up to 4 min) in order to capture sufficient projections (views) per respiratory phase. The purpose of this study was to evaluate different view interpolation algorithms to improve the image quality of
4D-CBCT facilitating shorter image acquisition times.
Materials: CBCT (Synergy, Elekta, UK) projections were acquired from a
Dynamic Thorax Phantom (CIRC, Norfolk, USA) over an arc of 200◦ and of
the acquisition times of 1, 2, 4 and 8 min. The phantom had a 3cm diameter sphere moving with 2 cm peak-to-peak amplitude in the cranial-caudal
direction and 4s period. The projections were sorted into 10 bins with theirmotion phase, and subsequently for each phase 1, 3, and 7 projections wereinterpolated in between each pair of projections for the 4, 2 and 1 min acquisition times respectively and finally reconstructed into a 4D CBCT. The linear
interpolation (LI) which took the average value from same pixels in the twoneighboring projections, and directional interpolations (DI) [1], which is theweighted sum of pixels in the neighboring projections based on local orientation analysis, were compared. Both interpolation schemes were implemented
in Matlab.The effect of interpolations was quantified by the Root Mean Square
Error (RMSE) of voxel value between reference (8 min scan) and faster acquired scans. Additionally, the effect of interpolation was quantified, by the
reproducibility of local rigid registration of each phase of the 4D-CBCT scan
to a 3D reference scan with 27 different starting positions (-0.5, 0, and 0.5 cm
in X, Y, and Z direction respectively), with a 0.5cm shaped region of interest
around GTV.
Results: RMSE[HU] of no-interpolation, LI, and DI were 5.55, 5.52, and 5.41
for 4 min, 7.42, 6.94, and 6.71 for 2 min, and 12.91, 7.01, and 6.93 for 1
min. The standard deviation (SD) of registration result is depicted in Fig.1.
Smaller SD indicated more stable registration results associated with better
discrimination of local image structures. In Fig.1, the increment of view-angle
gap decreased accuracy of directional estimation, which resulted in worse
performance of DI. DI time for each projection in 4, 2, and 1 minute scan were
2.07, 3.16, and 3.88 s (more interpolated projections in between consumes
more orientation analysis time), and LI time were 0.01, 0.01, 0.02 s on Intel
Core Duo E8500 3.06G.

still contains image artefacts due to irregular breathing and large tumour motion. Such artefacts have a significant impact on the delineated GTV [R&O
96, 2010, 61] which will change the definition of the tumour and thus lead tosystematic treatment uncertainties. Therefore, an optimisation of the image
quality in 4D CT is warranted. Typically, reconstruction of a specific respiration phase of a 4D CT is only based on the fraction of acquired raw data
directly related to that phase (e.g. 1/10 of the data). A deformable image
registration of the phases to each other will make it possible to transfer image information between the phases, thereby facilitating improvements of theimages by use of information from all the raw data. In this study deformableregistration will be used to improve the image quality of 4D CT.
Materials: 4DCT scans, each divided in 10 respiration phases, of seven earlystage lung cancer patients were analysed in this study. For each patient thephases were deformable registered to each other, thereby producing 10 image sets for each phase (9 registration/phase0 phases = 90 registrations).
For each phase, a mean over the 10 images sets in each phase was calculated in order to generate a new 4D CT. All registrations were performedby the open source software Elastix [IEEE Trans on MedImg 29, 1, 2010].
An experienced radiation oncologist manually outlined the GTV in all phasesof the original and the new 4DCT scan in order to measure the variation in
the imaged tumour volume throughout the respiration phases. A coefficientof volume variation (std.dev./mean) was calculated and the tumour motion
was measured in both 4D scans. The tumour motion was obtained by a rigid
image registration based on an expanded tumour region.
Results: The visual image quality of the new 4D CT is clearly improved relative to the original data (see figure). The mean coefficient of tumour volume
variation was substantially decreased from 31% in the original 4D CT scans
to 16% in the new 4DCT scans. The tumour motion was unchanged between
the two datasets (Pearson correlations for LR: 0.89, AP: 0.97, and CC: 0.92;
p<0.001 for all three) showing that the 4D information of the processed images are equal to that of the original ones.

1181 poster
IMAGE IMPROVEMENT OF 4D CT USING DEFORMABLE REGISTRATIONS OF THE RESPIRATION PHASES
C. Brink1 2 , T. B. Nielsen1 2 , G. Persson3
1
U NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark
2
O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
Denmark3
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of Radiation
Oncology, Copenhagen, Denmark
Purpose: Breathing related image artefacts and positional errors can be minimised by the use of 4D imaging techniques. However, conventional 4D CT

IGRT: Adaptive treatment schemes
and correction strategies
1183 poster
A DOSIMETRIC METHOD TO DERIVE OPTIMAL COUCH CORRECTIONS IN THE PRESENCE OF ANATOMICAL DEFORMATIONS FOR
H&N CANCER
A. Mencarelli1 , S. R. van Kranen1 , C. Rasch1 , M. van Herk1 , J. J. Sonke1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands

Conclusions: It is possible to reduce artefacts in 4D CT images substantiallyby use of deformable image registration. Such a reduction of image artefacts decreases the uncertainty in tumour definition during treatment planning. This method only requires access to the reconstructed images and not
the raw data. Thus, the suggested image improvement can be performed ondata from any CT scanner. Furthermore, since the deformable image registration is performed by use of open source software it is possible for any
institution to obtain similar image improvements.

Conclusions: DI better maintained the directional feature of sinogram aroundbony anatomy, which resulted in improved reconstructed image quality. Theinterpolated methods were validated by 4D phantom, and DI brings appreciable improvement both on RMSE and registration accuracy. [1] Bertram et al.,IEEE Trans. Med. Im., 28, 2009.

the internal motion with respect to the respiratory signals. Patient coachingbased on audio guidance and video feedback was also implemented in orderto stabilize the amplitude and frequency of the respiration. Additional 4D-CT
images were acquired to check the model reproducibility.
Results: Preliminary results indicate that a linear combination (LC) of theexternal respiratory signals is better correlated with the internal tumour motion than any single signal. The audio/video coaching significantly improves
the reproducibility of the respiratory signals. The mean breathing amplitude,from the epigastric area, is 18.30 ± 1.16 mm with a mean breathing periodof 5.64 ± 0.16 sec. The Pearson correlation coefficient (CC), used to determine the shape reproducibility of the signal, is 0.96.The average internal
superior-inferior tumour amplitude is 7.31 ± 1.01 mm with a shape reproducibility of 0.91.Up to now, the linear model based on the LC appears to be
the more reproducible, with a mean error of 0.95 ± 0.89 mm. Majors factorsthat could jeopardize model reproducibility are likely to stem from a baseline shift (2.66 ± 1.24 mm) of the internal respiratory motion or from tumour
volume decrease due to RT.
Conclusions: According to these results, magnetic sensors could be used inclinical settings. Audio/video coaching is essential to ameliorate reproducibility of the breathing signal and model reproducibility is improved using thelinear model based on the LC of multiple external sensors. However, further
analyses on additional patients are still needed to confirm current conclusions.

1182 poster
MAGNETIC SENSORS TO MODEL THE RELATIONSHIP BETWEENINTERNAL MOVEMENT OF LUNG TUMOURS AND PATIENT RESPIRATION.
S. Goossens1 , D. Bertrand2 , F. Senny3 , E. Graas4 , X. Geets1
1
UCL C LINIQUES U NIV. S T.L UC, IMRE, Brussels, Belgium
2
IBA S . A ., Louvain-la-neuve, Belgium
3
M ONTEFIORE I NSTITUTE UL G, Liège, Belgium
4
N OMICS, Angleur, Belgium
Purpose: Accurate tracking of internal motion allows better targeting of
bronchial tumours in radiation therapy (RT). In this context, the aim of ourstudy was to model the relationship between the internal motion of bronchial
tumours and external measurements of respiratory motions with non-invasive
magnetic sensors.
Materials: A cohort of 20 patients was planned to undergo four-dimensional
computed tomography (4D-CT), in order to determine the internal movementof bronchial tumours. Respiratory signals were recorded using three magnetic distance sensors placed on the patient skin on the epigastric area, thechest wall and the thoracic flank. Mathematical models were built to predict

Purpose: Considerable posture and anatomy changes occur in head-andneck (H&N) cancer patients during RT. In the past we developed a multiple
region of interest (mROI) registration technique and derived couch corrections using the mean displacement. In the presence of anatomical or posturechanges, however, residual discrepancies remain after a couch shift, and deriving geometric tolerance limits for these discrepancies is non-trivial. The
purpose of this study was to develop a dosimetric method to derive the optimal couch shift in the presence of anatomical deformations.
Materials: First, CBCTs acquired prior to treatment were registered to theplanning CT using multiple ROIs around bones and cartilages; subsequently
these registration results were averaged over the ROIs to calculate the initial couch shift (geometric correction). The local residual deformations of thesurrounding tissue were extrapolated using thin-plate splines. By deforming
the planned dose with the inverse of the resulting deformation field, the delivered dose was estimated. Next, an equivalent uniform dose (EUD) based
cost function was calculated with a=-20 for the CTV, a=20 for brainstem andspinal cord, and a=1 for the parotid glands. Finally, assuming shift invarianceof the dose, the couch shift was optimized (using the simplex algorithm) according to a cost function based on a weighted sum (-0.75 CTV, 0.25 OAR) of
these dose values (dosimetric correction). The method was tested for 5 H&Ncancer patients.
Results: The optimization process takes about 60 s. For the tested cases,
the mean and standard deviation (SD) of the difference between the geometrical and the dosimetric couch corrections in the left-right, cranial-caudal andanterior-posterior directions were 0.5, 3.5, -2.8 mm and 1.0, 1.4, 1.6 mm, respectively. The effects of no correction, geometrical correction, and dosimetric correction on the dose parameters for each structure are given in Table 1.
The dosimetric couch correction does the best job recovering the CTV dose
while keeping the OAR dose parameters close the planned ones. Due to thedeformations, the brainstem and parotids dose values actually reduced.
Conclusions: A fast correction method based on dosimetric analysis wasdeveloped that allows finding the best couch shift to account for anatomical
deformations.

S 441

1184 poster
AN ANALYSIS ON DOSE COVERAGE IN BLADDER CANCER USING
THE TOMOTHERAPY ADAPTIVE RADIOTHERAPY APPLICATION
V. Althof1 , C. Niël1 , W. Altena1 , E. Bekhuis1 , L. Geukes1 , M. Oplaat1
1
R ADIOTHERAPEUTIC I NSTITUTE RISO, Deventer, Netherlands
Purpose: To evaluate the impact of bladder filling on the accumulated total
bladder dose.
Materials: We evaluated 12 patients, treated with curative intent for invasive
bladder cancer (323 fractions, 443 MVCT’s, February 2008 to September2010). Two out of 12 patients used diuretic medication. The PTV consists ofthe bladder (CTV) with 1cm isotropic margin. The patients were instructed toempty the bladder just before kVCT scan and treatment. Bladder volume asoutlined on the kVCT and the kVCT based treatment plan dose distribution,
served as the gold standard. At least 99% of the PTV received at least 95%(1.9 Gy) of the prescribed dose. All patients were treated on a Tomotherapy
Hi-Art II and underwent daily MVCT imaging and 3D on-line position correction prior to every dose delivery. 5 out of 12 Patients also underwent a MVCT
scan directly after the dose delivery. The bladder was outlined on each MVCT.
The delivered dose was reconstructed on the MVCT using the planned adaptive application in Tomotherapy. Variation in bladder volume (inter- and intrafraction) and D99|ctv (dose to 99% of the CTV) were calculated.
Results: The mean pre-delivery MVCT bladder volume was 36 cc smaller
than the KVCT volume, with a mean variation of 29 cc (1 SD). However, patients who were using a diuretic showed larger variations, especially in the
post-MVCT volumes: mean 32 cc larger than the KVCT, with a mean variation of 68 cc (1 SD). For those patients who did not use a diuretic, the dosecoverage was good in both pre- and post-delivery MVCT: D99| ctv = 1.93
Gy (1SD=0.06 Gy). Dose coverage calculated on the post-delivery MVCTwas not adequate for the two patients using a diuretic: D99| ctv = 1.72 Gy (1SD=0.3 Gy). The mean duration between the pre- and post MVCT was 15
minutes. The mean bladder fill rate found for patients using a diuretic was 4.4
cc/min (max 13.5 cc), while the mean for the patients without a diuretic wasmuch less: 0.9 cc (max 3.0 cc).
Conclusions: The current isotrope CTV V margin of 1 cm, in combination
with the ’empty bladder’ instruction, was adequate, except for patients who
use a diuretic.
1185 poster
ANALYSIS OF ROTATIONAL COLLIMATOR ANGLE ADJUSTMENTS
FOR THE PROSTATE AND SEMINAL VESICLES DURING VMATJ. de Boer1 , R. Rozendaal1 , M. van Herk1 , J. J. Sonke1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiation Oncology, Amsterdam, Netherlands
Purpose: Rotations of the prostate mainly occur around the left-right (LR)axis and these rotations can be efficiently corrected by collimator angle adjustments (Rijkhorst et al. IJROBP 2007). This correction strategy, however,was previously validated for step-and-shoot IMRT treatments only. Modern
VMAT treatments include a wide range of beam orientations that differ in modulation. The aim of this study was to validate our rotation correction strategy
also for VMAT dose delivery. Such a procedure requires dynamic collimator
rotation, which is possible on modern treatment machines.
Materials: Inversely optimized VMAT plans were created for ten prostate cancer patients. Gantry angles (single arc) ranged from -140◦ to +140◦ . The
CTV consisted of the prostate and seminal vesicles. The CTV-to-PTV margin
was 7 mm and an additional boost dose was given to the prostate with a 4 mm
margin. EPID dosimetry images were acquired during treatment and binned
for each 2◦ segment of the arc. Using the planning CT and EPID image, thedelivered 3D dose for each segment was calculated by our back-projecting
based portal dose reconstruction algorithm. This reconstruction is accurate
within 3%. The total delivered 3D dose was calculated by accumulating overall segments. We simulated prostate LR rotations between -20◦ and +20◦ .
These rotations can be partially corrected for by rotating the collimator overangle θ =αsin(β ), where α is the LR rotation and β the gantry angle. The
effect was simulated by rotating the reconstructed 3D dose of each segment
around the collimator axis by an angle of θ . The minimum CTV doses (Dmin)of the simulated dose, with and without collimator correction, were comparedwith the original CTV dose.
Results: On average, the difference between corrected Dmin and originalDmin was smaller than 5%, except for very large positive prostate rotations(Fig. 1). This is expected, because seminal vesicles and apex rotate outof AP oriented beams for positive rotations, whereas they remain almost fully
covered for negative rotations. The largest dose difference (-16%) occurred at
the tip of the seminal vesicles when the LR rotation was +20◦ . The correction
strategy improved dose coverage for all prostate rotations.

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IGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIESIGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIES

normal tissue dose constraints. Analysis of target coverage and dose to surrounding normal tissues in each phase is ongoing. Recruitment to and followup within the study continues.
1188 poster
DOSIMETRIC CONSEQUENCES OF ANATOMIC VARIATIONSDURING HEAD-AND-NECK RADIOTHERAPY TREATMENT
M. Marguet1 , S. Warren1 , M. C. Bordage2 , R. Garcia1
1
2

Conclusions: Our analysis showed that, for VMAT treatments, collimatorangle adjustments can safely correct LR rotations of the prostate and seminal
vesicles. Slight under-dosage at the tips of the seminal vesicles and apex,
however, can remain for large positive LR rotations.
1186 poster
BEYOND IMAGE-GUIDED RADIOTHERAPY FOR PROSTATECANCER? - PREDICTORS FOR TARGET UNDERDOSAGE INSIMULTANEOUS INTEGRATED BOOST TREATMENT OF LOCALLYADVANCED DISEASE
S. Thörnqvist1 23 , L. Bentzen3 , L. B. Hysing4 , J. B. Petersen1 , L. P.
Muren1 23
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
2
A ARHUS U NIVERSITY, clinical institute, Aarhus C, Denmark
3
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
4
H AUKELAND U NIVERSITY H OSPITAL, Department of oncology and medical
physics, Bergen, Norway
1

Purpose: Optimal image-guidance strategies in simultaneous integrated
boost treatments to prostate and pelvic lymph nodes (LN) are challenged
by the uncorrelated motion of the two targets as well as large deformationsof nearby organs at risk. Consequently, image-guided approaches might beinsufficient and treatment plan adaptations needed. The aim of this study
was to evaluate the ability of geometrical parameters to predict target underdosage (TUD), indicating the need of treatment plan adaptation.
Materials: The study included nine patients with 8-9 repeat CT-scans evenly
distributed throughout their treatment course. The prostate target (GTV-P)
and the LN target including seminal vesicles (ITV-LN) were delineated by asenior oncologist in all scans. Margins of 5 mm except 7 mm in the craniocaudal direction (CC) were added to the GTV-P and margins of 7 mm/9 mm(CC) were added to the ITV-LN. Treatment plans (RapidArc, 2 arcs) weregenerated in Eclipse planning system (Varian Medical Systems) and transferred to the repeat CTs for dose re-calculation using registration based oneither bony anatomy or intra-prostatic fiducial markers. TUD was defined asD99<95% of the prescribed dose in each repeat CT-scan. Three parameters
to describe TUD were explored: 1) The relative change in target volumes(GTV-P and ITV-LN) as compared to those used for planning, 2) The distance (in 3D) found comparing the different translations obtained from thetwo registration methods, and 3) Dice similarity coefficient (DSC), a volumetric parameter including information of the spatial overlap. Receiving operating
characteristic (ROC) analysis was used to compare the three parameters andextracting the crossover, the point where the maximum number of scans arecorrectly classified as positive/negative.
Results: Registration based on bony anatomy resulted in three situationsof TUD for GTV-P and seven for ITV-LN. For GTV-P the crossover between
sensitivity and specificity was 0.93 for relative volume, 0.85 for DSC and 0.66
for the distance. Corresponding crossover values for ITV-LN were lower; 0.72
for the relative volume, 0.70 for DSC and 0.64 for the distance. Using fiducials
for image-guidance gave one situation of TUD for GTV-P and five for ITVLN and only the ITV-LN were used for ROC analysis. This gave cross-overvalues for ITV-LN of 0.74 for the relative volume, 0.65 for DSC and 0.63 forthe distance.

Conclusions: For both targets the largest values in sensitivity and specificity
of predicting TUD was seen for the relative volume followed by DSC. Notably,
the lowest values were found for the distance. The differences in the ability
to predict TUD were reduced for all parameters when evaluating the ITVLN, illustrating the complexity of this target including both LN and seminal
vesicles. Re-planning approaches should aim for improved robustness forthese complex motion patterns, which will be investigated in future studies.
1187 poster
DOSE-ESCALATED BLADDER RADIOTHERAPY: EARLY CLINICALRESULTS
F. McDonald1 2 , S. Lalondrelle1 2 , V. Harris1 2 , H. Taylor2 , K. Warren-Oseni2 ,V. Hansen2 , K. Jones2 , V. Khoo3 , R. Huddart1 2
1
I NSTITUTE OF C ANCER R ESEARCH, Sutton, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Sutton, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom

I NSTITUT S AINTE C ATHERINE, Avignon - Cedex 02, France
L APLACE, Toulouse, France

Purpose: Anatomic variations during head-and-neck radiotherapy treatment
may compromise the delivery of the planned dose distribution, particularly inthe case of IMRT treatments. The aim of this study was to establish dosimetric indicators to identify patients whose delivered dose deviates from theplanned dose to allow an eventual re-optimisation of the patient’s dosimetry,
if necessary, during the course of their radiotherapy treatment.
Materials: Basic indicators such as the position of the parotids with respect
to high dose gradient regions in the planned dose distribution at the startof radiotherapy may help to identify patients "at risk" of significant dosimetric changes during the course of their treatment. The study was carried out
without the need of any additional contouring ; the patient dose distribution
analysis and comparison was performed from the initial CT and repeated
CT or CBCT using a modified gamma index technique that we named gammaLSC3D. This improved gamma index technique quantified and identified
the location of changes in the dose distribution in relation to the planned
dose, in a stack of 2D images, pixel by pixel, with particular reference to thetarget volume (PTV) or organs at risk (parotids) location. Moreover, the superimposition of gammaLSC3D indicator maps with CT or CBCT maps was
implemented in order to visualise the dose deviation information directly on
the organs. You can see an example for a patient in Figure 1.

Purpose: To study the position of the stent in pre-treatment MVCT images
with respect to the stent on the planning KVCT and analyse the possibilityof using it as a surrogate for tumour during matching for daily registrationin cases of carcinoma gall bladder and pancreas treated on Tomotherapy Hi
ART system.
Materials: Patients of carcinoma pancreas and gall bladder with endobiliary
stents were included in this study. Computed tomography (CT) was carriedout as a part of treatment planning in all patients. Patients were treatedon Tomotherapy Hi ART system with Mega Voltage Computed tomography(MVCT) images acquired prior to every fraction delivered. Both the planning
CT and MVCT of the first seven fractions were transferred to the focal sim(Vs) contouring station. The planning CT of each patient was independently
fused with each of the seven MVCT images of that particular patient usingalignment with the vertebral body, liver and the kidneys. The stent was thencontoured on the planning CT and the seven MVCT images for each patient.
During contouring on the MVCT images, the contours on the planning CT
were turned off. The centre of mass (CM) of the stents both on the planning
as well as the seven MVCT images was found for all patients. The difference
between the three co-ordinates of the CM of planning and MVCT was found.
The mean of these differences across all patients was calculated.
Results: Results: Three patients of gall bladder cancer and two patients ofcarcinoma pancreas were included in the study. A total of five CMs of thestents on the planning CT images and thirty five CMs of the stents on the
MVCT images were obtained. In total thirty five readings for difference in theplanning and MVCT CMs were thus obtained. The mean of difference in CMs
in the right -left, supero-inferior and antero-posterior directions was found tobe 0.16 cm (±0.7), 0.22 cm (±2.07) and 0.36 cm (±0.7) respectively.
Conclusions: The study validates the use of endobiliary stents in gall bladderand pancreas cancers as stable tumour localization surrogates. In this regionof body in which there is an absence of any fixed bony point for daily pretreatment matching, stent can be used as a reliable surrogate for tumour andcan be used as a valuable method to correct for interfraction target motion andto improve precision in the delivery of radiotherapy in patients of carcinoma
gall bladder and pancreas.
1190 poster
EVALUATION OF DEFORMABLE IMAGE CO-REGISTRATION IN
ADAPTIVE IMRT FOR HEAD AND NECK CANCER
A. M. L. Olteanu1 , I. Madani1 , W. De Gersem1 , T. Vercauteren1 , W. De
Neve1
1U NIVERSITAIR Z IEKENHUIS, Department of Radiotherapy, Gent, Belgium

Purpose: The purpose of this prospective phase I study is to assess feasibility and safety of dose escalation for localised muscle-invasive bladdercarcinoma using image-guided and adaptive radiotherapy (RT) techniques
combined with a reduced high-dose tumour boost volume.
Materials: Planning scans were performed at 0, 30 and 60 minutes post void
(CT0/CT30/CT60). Treatment was planned in 3 phases (Table 1). Phase
1 and 3 combined for the whole empty bladder were prescribed to 50Gy in
25 fractions. In phase 1 cone beam (CBCT) images are acquired to be assessed to determine the adaptive approach for phase 3. If all day 1 to 5 CBCT
CTVs were covered by PTV1 a composite technique was chosen otherwise
adaptive-predictive organ-localisation (A-POLO), using patient-specific bladder filling information between CT0 and CT30, was chosen to create 3 plansfor optimal plan of the day selection. In phase 2 a partial comfortably full
bladder volume around the gross tumour was treated either to give a total
standard dose of 64Gy (SD) or, if all normal tissue dose-constraints weremet, the escalated dose of 68Gy (ED). The primary endpoint is late toxicity.

Results: 14 patients were recruited between May 2009 and October 2010.
For all patients we adapted the phase 3 plan based on the CBCT from phase
1, while the patient had phase 2 delivered. 9 sets of plans met the normal
tissue constraints for escalated dose to the reduced high-dose volume. 5
patients (4 ED, 1 SD) received concomitant chemotherapy with 5FU and Mitomycin C. 8 patients (5 ED, 3 SD) had a composite volume selected for theirphase 3 adaptive technique and 6 (4 ED, 2SD) were treated using A-POLO
plan of the day selection. 1/5 (20%) SD patients and 2/9 (22%) ED patients
experienced G3 acute toxicity (CTCAE v3.0). 1/9 (11%) ED patients, also
on concomitant chemotherapy, experienced acute G4 neutropenia. With a
median follow-up of 6.2 months, there have been no grade ≥3 late toxicities(RTOG).
Conclusions: Implementation of image-guided and adaptive RT techniqueswith reduced high-dose volume strategy allow for a proportion of patientsto achieve tumour dose-escalation within normal tissue constraints. Toxicity data to date suggest tolerability of 68Gy in the patients whose plans met

S 443

Results: The changes observed in the dose distribution for the PTV orparotids were analysed and presented in the form of gammaLSC3D-volume
histograms in order to facilitate the follow-up of dosimetric changes during theradiotherapy treatment. We suggest a replanification for patients whose morethan 5% of the selected pixels do no match anymore with planned dose.
Conclusions: This analysis method has been automated in order to makeit applicable in clinical routine to have the follow-up of dose variations during
head and neck radiotherapy treatment.
1189 poster
ENDOBILIARY STENT: A SURROGATE MARKER FOR PATIENTALIGNMENT IN IGRT IN CARCINOMA GALL BLADDER AND
PANCREAS
R. Engineer1 , P. Shukla1 , S. Chopra1 , Z. Master2 , S. K. Shrivastava1
1

TATA M EMORIAL H OSPITAL, Department of Radiation Oncology, Mumbai,
India
2
TATA M EMORIAL H OSPITAL, Department of Medical Physics and Radiation
Safety, Mumbai, India

Purpose: to assess accuracy of contour deformation applying deformableimage co-registration in adaptive IMRT for head and neck cancer.
Materials: Data of 12 patients with non-metastatic head and neck cancer
treated at the highest dose level of the phase I trial on adaptive 18 F-FDGPET-voxel intensity-based intensity-modulated radiotherapy (IMRT), i.e. dose
painting by numbers (DPBN) were used in this study [1]. Each patient had two
DPBN plans followed by conventional (homogenous dose) treatment. The initial DPBN plan was based on a pre-treatment PET/CT scan, while the second,
adapted DPBN plan (fractions 11-20) was based on a PET/CT scan acquired
after the 8th fraction. The median prescription dose to the dose-painted volume was 30 Gy for both DPBN plans. The median dose prescription for theconventional plans (fraction 21-32) was 26 Gy. A commercial available software package MIMvista, version 4.2 (MIM Software Inc., Cleveland, OH) applying intensity-based free-form deformable registration algorithm was used
for deformation of contours of pretreatment CT to per-treatment CT. Jaccard(JI) and overlap indices (OI) were computed for deformed regions of interest(ROIdef) as well as regions of interest deformed and adjusted at discretion ofan experienced head-and-neck radiation oncologist (ROIdef_ad) in comparison to the manually redrawn ones (ROIm).
Results: The radiation oncologist chose to adjust almost all deformed ROIs
in all patients. Variable results were obtained for the GTV depending on tumor
response: the largest adaptations were made in patients with substantially regressing tumors (ROIdef=11.8 ± 10.9 cm3 vs. ROIdef_ad=5.9±7.8 cm3 vs.
ROIm=7.7 ± 7.2 cm3 [p=0.57]). The swallowing structures (superior, middle,
inferior pharyngeal constrictor muscles [SPC, MPC, IPC, respectively]; upper
esophageal sphincter [UES], esophagus and supraglottic larynx) represented
the most frequently adjusted ROIs. The mandible was well propagated andneeded little or no adaptations. JI and OI confirm these observations (Table)with the highest for the mandible (JI=0.8 and OI=0.9) and lowest for the UES(JI=0.3 for ROIdef and 0.4 for ROIdef_ad; OI=0.5 for both ROIs). Manualadjustment of deformed contours addressed uncertainty and artefacts. As aresult, indices of similarity (JI) and overlap (OI) were better between deformed
and deformed-adjusted ROIs, than between deformed and manually redrawn
ROIs, especially for the swallowing structures.

S 444

IGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIESIGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIES

Purpose: To generate a virtual daily planning CT for Head & Neck (HN)
adaptive radiotherapy treatments by means of deformable registration aiming
at reliable re-planning and sparing new CT scans to patients.
Materials: The study includes seventeen HN cancer patients, who underwent
CT scanning for treatment planning (CTsim), CBCT scans on a On-Board Imager (OBI, Varian Palo Alto, U.S.A.) at 95 KVP after 40Gy and 50Gy dosedelivery and re-planning CT scans (CTrepl). Amongst all the scans, we selected one or more triplet (CTsim, CBCT and CTrepl) per patient, in which
CBCT and CTrepl were acquired less than one week apart.To generate thevirtual planning CT, a multistage B-spline deformable registration between
CTsim and CBCT is performed following an initial stage of rigid registration(Figure 1). For validation purposes, we approximate the missing CBCT contours performing a rigid CTrepl-CBCT registration. No patient-specific tuning of the registration algorithms was performed.To assess the overall performances on our patient population, we estimate the mean and the standard
deviation of the patient-specific mean absolute image difference between therigidly adapted CTrepl and CBCT as well as between the warped CTsim andCBCT(i.e. systematic error). Finally, the Dice Coefficient (DSC) between therigidly adapted CTrepl contours and the warped CTsim contours on the CBCT
was calculated.
Conclusions: Visual inspection and adjustment are needed on the most
ROIs. Automatic ROI propagation followed by user driven adjustments appears to be more efficient than de-novo contouring on per-treatment images..
References 1. Duprez F, De Neve W, De Gersem W, et al. Adaptive Dose
Painting by Numbers for Head-and-Neck Cancer. Int J Radiat Oncol Biol Phys
2010 Jul 17. [Epub ahead of print].

3. For "rectal anterior wall" and "rectal posterior wall" 50% of circumference were contoured over length of rectum ptv
4. For all methods D50 (dose in Gy that achieved 50% of the volume ofthe organ) was evaluated. Further V70 (volume of organ in % that
achieved 70Gy) and V40 (volume of organ in % that achieved 40Gy)
were estimated
5. Dose calculation was performed in the planning CT
Results: Variability of rectum during radiotherapy treatment influences the
final administered rectum dose in comparision to planning CT evaluated dose.
Further the delineation method influences the perceived dose shown in thedose volume histogramm (DVH).Exemplary evaluation of a patient shown amean D50 for rectum (rectum ptv) of 31Gy with a range of 29 (37) to 36Gy
(45Gy) and 29Gy (39Gy). The mean V70 for rectum (rectum ptv) was 14%(22%) with a range of 13% (16%) to 19% (28%) and 10% (15%). For rectal
anterior wall a mean D50 of 70Gy was estimated with a range of 66 to 72Gy
and a mean V70 of 51% with a range of 38 to 59%. For rectal posterior walla mean D50 of 30Gy was estimated with a range of 29 to 30Gy and a mean
V40 of 11% with a range of 4 to 20%. Mean dose to rectal posterior wall was
62Gy.
Conclusions: Variability of rectum during radiation treatment and delineation
method influences the rectal dose in DVH. A more detailed rectum contouring
might result in a better estimation of rectal toxicity. The evaluation of rectum
volumes in CBCTs of the IGRT treatment leads to a more realistic estimationof rectal dose and therefore helps in decision of a desirable dose escalation.
The prospective of such an analysis is a more tight correlation between applied rectum dose and resulting toxicity.

1191 poster
1194 poster

FIRST CLINICAL RELEASE OF INTRA-FRACTIONAL, APERTURE
BASED IGIMRT FOR CORRECTIONS OF PROSTATE ROTATIONS
H. Deutschmann1 2
1
RADART - RESEARCH AND DEVELOPMENT ON ADVANCED RADIATIONTECHNOLOGIES , PARACELSUS M EDICAL U NIVERSITY , Salzburg, Austria
2
U NIVERSITÄTSKLINIK FÜR R ADIOTHERAPIE UND R ADIO -O NKOLOGIE,
Salzburg, Austria
Purpose: We developed and evaluated a correction strategy for prostate rotations using direct adaption of segments in intensity modulated radiotherapy(IMRT).
Materials: Implanted fiducials (4 gold markers) were used to determine interfractional translations, rotations and dilations of the prostate. The markers
were visualized and automatically detected in two pre-treatment planar X-ray
projections; their actual position in 3D space was reconstructed from theseimages. The structure set representation of prostate, seminal vesicles andadjacent rectum wall was transformed accordingly in 6 degrees of freedom (6DOF). Shapes of IMRT segments were geometrically adapted in a class solution forward planning approach, derived within seconds on-site and treated
immediately. Intra-fractional movements were followed in MV electronic portal
images (EPI) captured on the fly.
Results: For 39 patients / 1013 fractions (supine, flat couch, knee support,
comfortably full bladder, empty rectum), the online aperture adaption allowed
safe reduction of margins CTV-PTV down to 5 mm (SV 7 mm) when only interfractional corrections were applied: Dominant L-R rotations were found to be
5.3◦ on average, standard deviation ±4.9◦ , maximum at 30.7◦ ; 3D vectortranslations relative to skin markings were 9.3±4.4 mm (max. 23.6 mm).
Intra-fractional movements in 7.7±1.5 minutes (max. 15.1 min) between
kV imaging and last beam’s EPI showed further L-R rotations of 2.5◦ ±2.3◦(max. 26.9◦ ), and 3D vector translations of 3.0±3.7 mm (max. 10.2 mm).
Addressing intra-fractional errors could further reduce prostate margins down
to 3 mm (SV 5 mm).
Conclusions: We demonstrated the clinical feasibility of an online adaptive
image guided, intensity modulated prostate protocol on a standard linear accelerator to correct 6 DOF of internal organ motion, allowing safe and straightforward implementation of margin reduction and dose escalation.
1192 poster
GENERATION OF VIRTUAL DAILY PLANNING CT FOR ADAPTIVERADIOTHERAPY IN HEAD AND NECK CANCER
M. Peroni1 , C. Paganelli1 , M. F. Spadea2 , M. Riboldi1 , S. Comi3 , D. Alterio3 ,J. Seco4 5 , G. C. Sharp4 5 , R. Orecchia3 6 , G. Baroni1
1
P OLITECNICO DI M ILANO U NIVERSITY, Dipartimento di Bioingegneria,
Milano, Italy
2
U NIVERSITÀ M AGNA G RAECIA, Dipartimento di Medicina Sperimentale e
Clinica, Catanzaro, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Radiation Oncology,
Milan, Italy
4
M ASSACHUSETTS G ENERAL H OSPITAL C ANCER C ENTER, Department ofRadiation Oncology, Boston, USA
5
H ARVARD M EDICAL S CHOOL, Boston MA, USA
6
F ONDAZIONE CNAO, Pavia, Italy

IMAGE QUALITY FOR DIFFERENT CBCT ACQUISITION AND
RECONSTRUCTION METHODS TOWARDS RT PLANNING IN HEAD
AND NECK
U. V. Elstrøm1 , L. P. Muren1 , J. B. Petersen2 , C. Grau3
1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology and Departmentof Medical Physics, Aarhus C, Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
3
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
Results: The visual inspection revealed residual anatomical discrepancies
in the rigid registration outputs between the CTrepl and CBCT volumes, escalating as a function of time between the two scans. This suggests that ourapproach for verification is reliable if the CTrepl and CBCT were acquired lessthan one week apart. B-splines performed satisfactorily with only partial influence of image artifacts on registration quality. A patient-specific tuning of
the registration parameters might improve the results, but might not be desirable for online ART. The systematic error between the warped CTsim and
CBCT and the rigidly adapted CTrepl on CBCT were 12±8 HU and 46±19
HU respectively. Corresponding median DSC values were above 96% for
body, above 85% for temporal lobes, spine cord, mandible and brainstem andaround 70% for both left and right parotidis contours. Differences between
the 75th and 25th percentile were about 1%, less than 10% and between 10%
and 20% respectively.
Conclusions: Although dose and plan verification is still in progress, we areable to generate a virtual planning CT, which would drop the need for a new
CT scan for adaptation.
1193 poster
IGRT DOSE ESCALATION STRATEGIES FOR PROSTATE CANCER
S. Kuechler1 , N. Volegova-Neher1 , F. Röhner1 , G. Bruggmoser1
1
U NIVERSITÄTSKLINIK F REIBURG, Freiburg, Germany
Purpose: The purpose of this study is to evaluate the variability of rectal dose
during radiotherapy while using different delineation methods in contouring
the organ at risk. KV cone-beam CT (CBCT) acquired during radiotherapy
treatment sessions are used to calculate dose to rectal anterior and posteriorwall. Different methods for rectum delineation were studied.
Materials: Patients with localized prostate cancer who underwent primary
3D conformal radiotherapy receiving 74Gy (2Gy x 5 weekly) were chosen
for this study. All patients got four implanted gold fiducial markers and weretreated with daily IGRT (either kV-CBCT or orthogonal imaging). The CBCTs
were transferred to the planning system (Masterplan, Nucletron) and registered with the planning CT in respect to the table correction values during theradiation treatment. Delineation scheme for the OAR ’rectum’:
1. "Rectum" was contoured from below sigmoid flexure to above analverge
2. "Rectum ptv" was contoured from 2cm above to 2cm below CTV

Purpose: The aim of this study was to evaluate the image quality obtained in a standard QA phantom with both clinical and non-clinical conebeam CT (CBCT) acquisition modes for the head and neck (HN) region asa step towards CBCT-based treatment planning. The impact of deteriorated
Hounsfield unit (HU) accuracy was investigated by comparing results fromclinical CBCT image reconstructions to those obtained from a pre-clinicalscatter correction algorithm.
Materials: Five different CBCT acquisition modes on a clinical system forkV CBCT-guided radiotherapy (OBI v.1.4 on a Trilogy TX linear accelerator,
Varian Medical Systems, Palo Alto, CA) were investigated. Two protocols
were clinical 200 degree partial scan techniques, two were non-clinical 360
degree full rotation versions of the former, and the last was an older protocol at elevated x-ray energy. Image reconstruction was performed in bothstandard clinical software and with an experimental reconstruction algorithmwith improved beam hardening and scatter correction. Using the Catphan
504 phantom (The Phantom Laboratory, Salem, NY), quantitative measuresof HU uniformity, HU verification and linearity, contrast-to-noise ratio (CNR),
and spatial resolution using modulation transfer function (MTF) estimation
were assessed. To benchmark the CBCT image properties, comparison to
standard HN protocols on conventional CT scanners was performed by similar measures.
Results: The HU uniformity within in a water-equivalent homogeneous region was significantly improved, by factors of 2 for partial scans and 4 for fullscans, using experimental vs. standard reconstruction. Similar, the amount of
capping/cupping artifact were reduced by more than 1.5%. With a mode andreconstruction method specific HU calibration using 7 inhomogeneity inserts
comparable HU linearity were observed. CNR was on average 5% higher
for experimental reconstruction (scaled with the square-root of dose between
modes for both reconstruction methods) whereas MTF at 50% was 5% lower
due to smoothing in the scatter estimation.
Conclusions: Judged on parameters affecting the common diagnostic image
properties, improved beam hardening and scatter correction diminishes thedifference between CBCT and CT image quality considerably. In the pursuitof CBCT-based treatment adaptation, dedicated imaging protocols may be
the way forward, e.g. partial vs. full scan. The impact for CBCT-based dose
calculation is under investigation.

S 445

1195 poster
IMAGING THE POST-OPERATIVE BREAST TUMOR BED DYNAMICS:IMPLICATIONS FOR INTEGRATED AND ADAPTIVE BOOSTING
H. de Boer1 , N. Willems1 , M. Albregts1 , B. van Asselen1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands
Purpose: Target definition for adjuvant breast ca radiotherapy (RT) is complicated by the evolution of the excision cavity defining the tumor bed volume(TBV). Large changes can occur between breast sparing surgery (SG) andRT and potentially during RT. In this study we quantified these changes athigh time resolution using multiple CT and CBCT scans. Because the limited
visibility of the TBV on CBCT scans may preclude accurate identification, weinvestigated if fiducials could be used for TBV tracking.
Materials: For 20 patients treated with whole breast RT followed by a sequential boost, an initial planning CT (CTplan; on average 30 days post-SG
and 13 days pre-RT), a pre-boost CT (CTboost, after 3-4 weeks of RT) and a
final CT on the last day of RT were obtained. Furthermore every 2 fractions
a CBCT was acquired. On average, 17 CT scans (of which 14 CBCT) per
patient were available. On the 3 diagnostic quality scans, the TBV was delineated. On all scans, fiducials (mostly surgery clips but also gold markers)
surrounding the TBV were identified to establish the relation between fiducials
and TBV shape changes.
Results: TBV volumes on CTplan ranged from 3 to 238 cc. In 10 of 20 patients, a strong volume decrease (54%±19%) occurred between CTplan andCTboost. The almost linear relationship between TBV volume and CTplan
to bCTboost volume decrease found in a previous study (Tersteeg, IJROBP,
2009) was reproduced. However, the CBCT data showed that most of thisshrinkage (37%) actually occurred between CTplan and the first RT fraction
and was well traced by fiducials (fig. 1). Volume changes during the sequential boost (week 6 and 7 of RT) were small: on average 2% for an initial TBV> 5 cc. The TBV on CTboost overestimated the average volume during theboost phase by only 9% on average. The center of mass (COM) position of
the fiducials correlated well with the COM of the delineated TBV during thisphase (within 1-2 mm), indicating that fiducials could be used for TBV targeting. Furthermore, marker migration was minor (< 1 mm) during the boost
period. The random interfraction displacement of the fiducial COM was small(SD ≤ 2 mm in all directions) but systematic errors were larger (SD of 3 mm).

Conclusions: A planning CT obtained about 1 month after surgical excision
can seriously overestimate the TBV volume at the start of RT and may thus be
suboptimal, specifically for integrated tumor bed boosting. CT scans obtained
after a few weeks of RT for sequential boosting are in general representative.
Fiducials tracked the TBV accurately, were easily identified on CBCT, and canbe used for TBV positioning. The fiducials also provide information about the
dynamics of the TBV changes and hence could be applied in adaptive RT.
1196 poster
IMPACT OF 3 DIFFERENT SETUP CORRECTION STRATEGIES ON
DOSE COVERAGE OF THE TARGET VOLUME FOR H&N CANCERPATIENTS
E. M. Stoiber12 , M. Schwarz2 , K. Giske2 , P. Huber3 , J. Debus1 , R. Bendl2
1
U NIV.
K LINIKUM H EIDELBERG, Department of Radiation Oncology,
Heidelberg, Germany
2
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Medical
Physics, Heidelberg, Germany
3
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Radiation
Oncology, Heidelberg, GermanyS 446

IGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIESIGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIES

Purpose: To evaluate the impact of 3 different patient setup correction strategies on the dose coverage of the high-dose target volume (="boost") during
fractionated IG-IMRT for head-and-neck (h&n) cancer patients.
Materials: 4 h&n cancer patients received daily control Ct-scans using an
in-room Ct-scanner. Patients were positioned with a stereotactic setup approach (non-IGRT). 2 registration boxes were defined for the IGRT correction strategies: Registration box TRB (Target Registration Box) included thewhole target volume and box BRB (Boost Registration Box) the boost volume
only. IMRT plans with uniform dose prescription to target volumes and thespinal cord were generated for each patient. Only for the stereotactic positioning strategy a margin (to compensate for interfractional rigid motion) forthe boost was applied prior to treatment planning. Boost contours were rigidly
transformed to all control-Cts. The actually delivered mean dose to the boost
was then calculated on each control-Ct for 3 setup correction strategies: 1)
stereotactic positioning only (no setup correction, non-IGRT) and secondly atarget point correction derived from a registration of the 2) TRB and 3) BRB.
The optimized original treatment plan was then applied on each control-Ct tocalculate the dose distribution for the boost volume. Care was taken to apply the same monitor units to the reference point in each fraction. The dosecoverage of the boost volume was evaluated using the D95 and D5 value foreach fraction, and the obtained DVHs from all fractions of all 3 scenarios werecompared.
Results: The D95 values averaged over all fractions and patients and theirstandard deviations were 2.12 ± 0.04 Gy (stx + margin), 2.05 ± 0.05 Gy(BRB), 2.02 ± 0.07 Gy (TRB). Additionally the results for stereotactic positioning without margin were calculated for comparison and account for 1.98
± 0.10 Gy. The values show the superiority of stereotactic positioning including a margin in terms of boost dose coverage, followed by first the BRBand then the TRB IGRT scenario. However, this advantage is achieved bya large (4-7mm, depending on tumor localization) margin, including healthysurrounding tissue. As expected, stereotactic positioning without a margin is
the worst alternative.
Conclusions: We compared the dosimetric impact of non-IGRT- versus
IGRT-approaches in terms of dose coverage on the boost volume for 4 exemplary h&n patients. In particular, we analysed the effect of 2 different IGRT
correction strategies on this volume. In these 4 cases, stereotactic positioning (with margin) was superior to the IGRT scenarios. Yet, this was achievedat the expense of surrounding normal tissue exposure. The IGRT strategy
based on a registration of a BRB was superior to that with a larger TRB. Thiswas most evident in 1 patient with a comparatively small boost volume.
1197 poster
IMPACT OF CONE BEAM CT BASED IGRT ON DOSE DISTRIBUTION
IN CRANIAL RADIATION THERAPY.
P. M. Haertl1 , N. Repp2 , R. Loeschel2 , O. Koelbl1 , B. Dobler1
1
U NIV.- K LINIKUM R EGENSBURG, Klinik und Poliklinik für Strahlentherapie,
Regensburg, Germany
2
U NIVERSITY OF A PPLIED S CIENCES R EGENSBURG, Department ofComputer Science and Mathematics, Regensburg, Germany
Purpose: During the last years, IGRT has gained importance in fractionatedframeless stereotactic treatments of brain lesions. The purpose of this study
was to evaluate the influence of cone beam CT (CBCT) based IGRT on fractional and total dose distribution in cranial radiation therapy.
Materials: Seven intracranial tumour localisations were included in this study.
Treatment planning was performed with Oncentra MasterPlan v3.3 for a
SynergyS® (Elekta Ltd, Crawley, UK) linear accelerator with BeamModulator™head, XVI® Cone Beam CT, and 6MV photons. Dose prescription was
30 Gy delivered in 6 fractions. For verification and correction of the patient
setup, the XVI® system was used in combination with a HexaPOD™couch top(Medical Intelligence, Schwabmnchen, Germany). After initial patient setup
with respect to light markers, a CBCT study was acquired and registered tothe planning CT study. Patient positioning was corrected according to thecouch translations and rotations calculated by the XVI® system. Afterwards asecond CBCT study was acquired and registered to the planning CT to confirm the accuracy of the corrections. Since the CBCT data cannot be used
for accurate dose calculation, an in-house developed software was used fortransformation of the planning CT to the CBCT geometry, and dose calculations were performed on the transformed planning CT. Two dose distributions
were computed for each fraction, one for the case with and one without setup
correction and compared to the original plan to assess the influence of setup
inaccuracies. For the planning target volume (PTV) D95 and D05 are used
to show changes in target coverage and homogeneity, changes in organs at
risk (OAR) are given by D50. In addition margins around the PTV with 0.2 cm
and 1.0 cm were created and used for evaluation.
Results: The use of CBCT correction allowed to improve average setup deviation from ∆ translation = (0.5 ± 0.24) cm to (0.04± 0.05) cm. As a consequence dose deviations between real and planned dose distributions could
be reduced substantially. Details for PTV and Margins are given in table 1.
Deviations of dose to OAR were reduced as well.

S 447

when necessary. Adaptive radiotherapy might bring an additional dimension
to the management of patients with H&N cancer and has the potential tocounteract the effects of anatomical changes.
1200 poster
IS THERE A POSSIBILITY TO MAKE A GEOGRAPHICAL MISSWHILE CBCT PROSTATE BASED COUCH SHIFTS?
M. Adamczyk1 , T. Piotrowski1 , E. Adamiak2
1
G REATER P OLAND C ANCER C ENTRE, Medical Physics Department,
Poznan, Poland
2
G REATER P OLAND C ANCER C ENTRE, Radiotherapy Ward I, Poznan,
PolandConclusions: The use of CBCT based IGRT allows to increase accuracy
in patient positioning.Whereas real dose distributions differ substantially fromplanned dose distributions, if setup is performed to light markers only, differences are well below 2% if CBCT based IGRT is used for translational androtational corrections.
1198 poster
IN-TREATMENT CONE-BEAM CT AND IN-TREATMENT LINACPARAMETERS CAN REPRODUCE SEMI-ACTUAL DOSE DISTRIBUTION
A. Sakumi1 , A. Haga1 , S. Kida1 , N. Saotome1 , Y. Okano1 , K. Shiraishi1 , T.
Onoe1 , K. Yoda2 , K. Nakagawa1
1
U NIVERSITY OF TOKYO H OSPITAL, Tokyo, Japan
2
E LEKTA KK, Kobe, Japan
Purpose: Tumor registration using Cone-beam CT (CBCT) prior to radiotherapy has been increasingly adopted for daily clinical practice. We alreadyreported the clinical kilovoltage CBCT imaging during rotational radiotherapy
using a linac with a CBCT unit (Elekta Synergy, Crawley, UK) and volumetric modulated arc therapy (VMAT). On the other hand, we also reported thedose reconstructed by log data including actual data of MLC, jaw positions,gantry angles and MUs. To combine these two techniques has the potential
to provide an actual dose distribution during treatment. In this study, we report the dose reconstruction using in-treatment CBCT and in-treatment linac
parameters.
Materials: Pinnacle v9.0 SmartArc®(Phillips) treatment planning system(TPS) was employed to create a VMAT plan with a single arc for a prostatecancer patient. The single-arc VMAT delivery required approximately 120
seconds. During the treatment, kV beams orthogonal to treatment beams
were simultaneously delivered and in-treatment CBCT images were reconstructed from these kV projections off line. The CBCT images with HU filter estimated from water column phantom were then exported to Pinnacle
TPS, and the dose calculation was performed on these images using handtuned CBCT-to-density table. Also we calculated the dose using the log data
recorded by iCOM®(Elekta) which includes an information about actual MLC,
jaw positions, gantry angles and MUs with an interval of every 0.25s during
clinical treatment.
Results: Figure shows the feasibility image of the dose distribution calculated
by in-treatment CBCT images using log data from iCOM®at the same period.
This dose distribution was compared with that on planning CT with planninglinac parameters. The result of the difference of the mean dose at prostate
was only 1.2%. This difference may include the error arising from a poor
quality of CBCT image and uncertainty due to an inaccuracy of an employed
CBCT-to-density table. On the other hand, the error calculated with actual
linac parameter was negligible in the dose calculation.

Conclusions: The semi-actual dose distribution can be reproduced on intreatment CBCT. We note that the present method does not provide the actual dose distribution because it depends on an accuracy of the modeling of
TPS. In addition, a further study regarding an image quality of CBCT and its
deformation is required to improve the accuracy of dose reconstruction andthe adaptive radiation therapy.
1199 poster
IS ADAPTIVE RADIOTHERAPY NECESSARY IN HEAD AND NECKCANCER PATIENTS UNDERGOING IMRT?
Senkesen1 , E. Tezcanli2 , E. Goksel1 , M. Garipagaoglu2 , M. Sengoz2 , H.
Kucucuk1 , I. S. Aslay3
1
ACIBADEM KOZYATAGI H OSPITAL, Department of Radiation Oncology,
Kozyatagi - Istanbul, Turkey
2
ACIBADEM U NIVERSITY, Department of Radiation Oncology, Istanbul,
Turkey3
I STANBUL U NIVERSITY O NCOLOGY I NSTITUTE, Department of Radiation
Oncology, Istanbul, Turkey
Purpose: Head and neck (H&N) cancer patients might develop significant
weight loss or tumor volume reduction during radiotherapy (RT). Intensitymodulated radiation therapy (IMRT) has the capability to generate steep dose
gradients around the target volume; therefore it is very important to be awareof the dose distribution changes that might occur secondary to anatomical
modifications. These changes might result in doses higher than tolerance
levels in organs at risk (OAR) and a reduction in target doses, potentiallyaffecting the therapeutic index. In this study, we aimed to evaluate the volume and dosimetric changes of target and OAR that might occur during RT
secondary to weight loss or tumor shrinkage.
Materials: Six head and neck cancer patients undergoing treatment with
IMRT technique according to our clinical protocol developed anatomical
modifications during RT secondary to target volume reduction or structuralchanges were rescanned with a CT scan. The second CT scans were thenregistered to initial planning scans and the target and OAR volumes definedon the initial CT were transferred to the repeat scan without any changes. The
actual treatment plan was exported to the 2nd CT scan, all treatment parameters including the MU and dynamic MLC movements were left same. The
plan was recalculated in order to consider heterogeneity correction. Dosevolume histograms were evaluated for the treatment plans on both scans.
The doses received by 95% of the target volume (D95), mean target volume
and maximum, mean OAR doses were compared for both plans.
Results: When the volumes transferred to the repeat CT scan were compared with the initial CT scan, it was found that D95 values were lower than
the actual plan dose in 72% of the target volumes, while maximum doses
were found to be increased and mean doses to be decreased in all volumes.
Maximum and mean doses increased in 46% of OAR while mean doses increased in 64%.
Conclusions: Tumor shrinkage and weight loss in head and neck cancer
patients during radiotherapy change the target volume and body contours.
We found that anatomical changes and heterogeneity effect resulted in dose
distribution changes. These changes were consistent with OAR receiving
higher doses while the dose to the target volume decreased when comparedwith the initial treatment planning CT scan. Therefore, we recommend thepatients should be carefully evaluated regarding the anatomical changes thatmight occur during RT, and a second CT scan should be obtained in order toevaluate the dose distribution changes, and a new plan should be reoptimized

Purpose: Precise patient positioning by shifting the isocenter according to atarget daily position can be applied in clinical practice by using different image
guided radiotherapy (IGRT) techniques, like cone beam computed tomography (CBCT, Varian Medical Systems, Palo Alto, USA). The aim of this study
was to evaluate the impact of CBCT prostate based couch shifts on pelvic
lymph nodes dose coverage.
Materials: The study involved 10 consecutive patients who underwent 7
field intensity-modulated radiotherapy (IMRT) treatment of prostate cancer
in supine position. In all cases planning target volumes (PTVs) for prostate
gland (PTV1) and lymph nodes (PTV2) were created by adding 1 cm margin
to clinical target volumes (CTVs) in all directions, except for posterior margin,
where 0.5 cm was added. A dose of 50 Gy was delivered in 25 fractions.
Based on CBCT scans acquired prior to the treatment with intervals of 2-3
days, treatment fields were shifted according to an imaged prostate gland position. This may influence lymph nodes dose minimization as they are lying
along pelvic vasculature and remain stable without major inter- and intrafraction motion as it is observed for prostate gland. To check this potential daily
effect, doses were calculated on planning CT scans by shifting the isocenter
according to the recorded couch shifts.
Results: Analyzing dose-volume histogram (DVH) parameters for original
treatment plans, median mean planned dose delivered to lymph nodes
was 100.85% of prescribed dose, while median minimum and maximum
doses were 96.80% and 105.25% respectively. The same parameters forprostate gland equaled 100.35%, 97.95% and 103.15%. Taking into account IMRT prostate alignment, these values for lymph nodes changed into
100.77%, 95.70% and 103.88%, respectively, while for prostate gland theyremained stable as compared to original treatment plans (100.31%, 97,75%
and 102.25% respectively). Analyzing the DVH parameters for lymph nodes
in original plans, in case of two patients the minimum dose was lower thanrequired 95% (85.00% and 94.00%), but for both cases the 95% isodose covered more than 99% of the target volume. After shifting the isocenter, thissituation affected four patients but still the required dose was delivered tomore than 99% of lymph nodes volumes.
Conclusions: The results of this clinical study demonstrate that restricted
control of prostate gland motion by doing regular CBCT verifications gives theopportunity to deliver the prescribed doses exactly to target volume. What ismore, it was proven that when PTV margins are not reduced too much, IMRT
with prostate alignment done by CBCT-based couch shifts have no significant
impact on the lymph nodes dose coverage.
1201 poster
MARGIN-OF-THE-DAY: AN ONLINE ADAPTIVE STRATEGY FORCERVICAL CANCER PATIENTS
R. Ahmad12 , M. Hoogeman1 , P. Voet1 , L. Bondar1 , J. W. Mens1 , G.
Dhawtal1 , S. Quint1 , B. Heijmen1
1
E RASMUS M EDICAL C ENTER R OTTERDAM, Department of Radiation
Oncology, Rotterdam, Netherlands
2
U NIVERSITY K EBANGSAAN M ALAYSIA, Bangi, Malaysia
Purpose: Plan-library strategies based on pre-treatment established cervixuterus shapes have recently been proposed to compensate the large andcomplex cervix-uterus motion in cervical cancer patients [1]. Here we propose and evaluate a margin-of-the-day concept as a simple alternative. In
this concept, the plan of which the CTV-to-PTV margin is just encompassing the online localized CTV-of-the-day is selected for treatment from a plan
library with incrementing margin.
Materials: For 14 patients, 9-10 variable bladder filling CT scans were available, acquired at pre-treatment and after 40 Gy. In addition, bladder volume had been measured by an US device twice a week during the treatment
course. For each patient a library of IMRT plans was created with incrementing CTV-to-PTV margin in the planning CT scan (5 to 45 mm, in steps of 5mm). Based on the in-room US measurements, two treatment scenarios were
simulated. For each measured bladder volume, corresponding daily dose volume parameters were calculated as a weighted average of the parameters forthe pre-treatment and after-40-Gy CT scans with the nearest bladder volume(weights depending on time point in the fractionated treatment). In the firstscenario ("static" margin) each patient was treated each fraction with a margin such that in all fractions 99% of the CTV was covered by at least 95% of

S 448

IGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIESIGRT: A DAPTIVE TREATMENT SCHEMES AND CORRECTION STRATEGIES

the prescribed dose of 46 Gy. In the second scenario, for each fraction separately a margin-of-the-day was determined that ensured adequate coverage(V95% of CTV 99%). The required margins and dose to organs at risk were
evaluated for both scenarios.
Results: The required static margin was highly patient-specific and ranged
from 15 mm to 45 mm. The margin size was correlated with the observed
pre-treatment extent of motion (R=0.7; p=0.02). In the margin-of-the day scenario, the static margin could be reduced in 30%, 15%, 9%, and 8% of thefractions by 5, 10, 15, and 20 mm respectively. Only in 38% of the fractions
the relatively large static margin was required. The margin-of-the-day scenario spared the rectum (V37Gy), bladder (V37Gy), and small bowel (V45Gy)
by 28±22%, 24±22%, and 15±10% respectively. The sparing was patientspecific and ranged from no sparing to a sparing of 50-60% for patients withlarge cervix-uterus motion.
Conclusions: Online margin-of-the-day selection is a simple, but effective
tool to perform online adaptive treatments without the need of online treatment planning or a-priori knowledge on the possible shapes of the CTV. However, good quality volumetric imaging, for example by CBCT scanning, is aprerequisite to select the proper margin of the day.
1202 poster
OFFLINE ADAPTIVE REPLANNING FOR PROSTATE CANCER
TREATMENT: A DOSIMETRIC BASED MODEL FOR THE NUMBER
OF CBCT SCANS
P. Greer1 2 , J. Hatton3 , J. Parker1 , C. Tang1 4 , A. Capp1 4 , J. Denham1 4
1
C ALVARY M ATER N EWCASTLE H OSPITAL, Radiation Oncology, Newcastle,
Australia
2
U NIVERSITY OF N EWCASTLE, School of Mathematical and PhysicalSciences, Newcastle, Australia
3
U NIVERSITY OF N EWCASTLE, School of Mathematical and PhysicalSciences, Callaghan, Australia
4
U NIVERSITY OF N EWCASTLE, School of Medicine, Callaghan, Australia
Purpose: To ensure optimal and consistent delivery of the prescribed doseto the prostate and normal tissues, ideally daily plan adaptation is required,however this is not currently practical. A realistic alternative is to estimate theaverage patient anatomy using n cone-beam CT (CBCT) scans and adapt thetreatment plan for subsequent fractions. An implementation of this approachhas been reported using the combined contours from CT scans acquired at
the first 5 fractions(Nijkamp, J., et al., Int. J. Radiat. Oncol. Biol. Phys, 2008.
70:75-82). The aim of this project is to develop a dosimetric model of how
many CBCT scans are required to predict the average treatment prostateand normal tissue doses for adaptive replanning.
Materials: Twelve prostate patients were treated using daily implanted fiducial guidance and following a bladder and rectal preparation protocol. A uniform CTV to PTV margin of 0.7 cm was used. CBCT scans were acquired
twice weekly and contoured by a radiation oncologist for prostate, rectum andbladder. The planned beams were applied to all CBCT scans to determine
the delivered dose distributions. Prostate dose coverage was assessed by
the proportion of the CTV encompassed by the 95% and 98% isodose (V95,
V98). Rectal doses were assessed by the volume receiving at least 70 Gy(V70). The average dose metrics from CBCT scans 1 to n were calculated
and compared to the overall treatment average values. The mean (m) andstandard deviation (sd) of the differences between the calculated values andthe treatment average were determined.
Results: For prostate dose coverage only one CBCT scan was required todetermine m(V95) and sd(V95) within 0.2%. The m(V98) for the group waswithin 0.7% after 1 CBCT scan. A logarithmic function described the reduction in sd(V98) with n as sd(V98) = -1.3673 ln(n) + 3.8261 (R2 = 0.986). Them(V70) was within 0.5% after 2 CBCT scans. The sd(V70) was fitted bysd(V70) = -0.9838 ln(n) + 2.7459 (R2 = 0.964).
Conclusions: This work develops a dosimetric determination of how many
CBCT scans are required to predict the average treatment prostate and normal tissue doses for adaptive replanning. The precision of the estimates of
prostate dose coverage and rectal dose with the number of CBCT scans isderived using logarithmic fits to experimental data. Using clinically defined
precision limits, the number of CBCT scans for offline adaptive replanning
protocols can then be derived.
1203 poster
PATIENT MOVEMENT DURING THE FIRST FRACTIONS INVALIDATETHE STANDARD NAL-PROTOCOL
K. Fransson1
1
C OUNTY H OSPITAL K ALMAR, Department of Medical Radiation Physics,
Kalmar, Sweden
Purpose: One way to reduce patient set-up errors in external radiotherapy
is to measure the position during the first n treatment fractions, and to perform an unconditional correction of the set-up position at the (n+1)th fraction.
This strategy is known as the "no action level" (NAL) protocol. However, clinical observations indicate that there could be a presence of a progressive

displacement with time during the first fractions, especially for breast cancer patients. A possible reason to this time trend can be that the patient ismore tense in the beginning of the treatment and then relaxes. If a pure NAL
protocol is used in this situation, there is a risk for over- or underestimationof the systematic error. The purpose of this study is to investigate if such atime trend is present and to find an optimal correction strategy for patients
receiving tangential breast irradiation.
Materials: All patients treated with tangential breast irradiation within a six
month’s period are included in the study. Portal images of the two main tangential fields are acquired at every fraction during the course of treatment.
The images are acquired during treatment, and, hence, do not contribute to
any additional dose or prolonged treatment time. Each patient’s set-up deviation is determined by comparing the simulator image with the current portal
image. Once the statistical characteristics of the deviation are known, different set-up correction strategies found in the literature (NAL, extended NAL(eNAL), shrinking action level (SAL)), as well as new modifications of NAL,
are applied and analysed in order to find the optimal correction strategy.
Results: Initial results support the hypothesis that a time trend is present
during the first fractions, which invalidate the standard NAL protocol. Basedon these results, a new correction strategy, consisting of to different steps, is
proposed. The first step includes on-line set-up corrections during fractions
12, when the patient is tense and the portal images do not adequately represent the average set-up deviation. The next step is off-line evaluation of
the portal images taken during fractions 35, when the patient is more relaxed.
The mean of these measurements are then estimated to be the individual
set-up deviation, which, subsequently, is corrected for.
Conclusions: Current data suggest that the strategy described above ismore feasible in correcting for the early-treatment displacement due to patient relaxation.

S 449

a*SI(t)+b*SI(t-τ )+c; τ =1 sec. The correlation model parameters were determined with least-square estimation by minimizing the discrepancy between
the measured and model-estimated projection positions. The accuracy ofthe proposed method was evaluated by simulating CBCT acquisition with twolarge clinical 3D tumour trajectory data sets: 160 thorax/abdomen tumour
trajectories from Cyberknife Synchrony and 536 prostate trajectories from
Calypso. Each trajectory was divided into 60-second interval, and for eachtrajectory-segment the CBCT image projections were mimicked with 600 projections for a 360◦ rotation. The estimation errors were quantified by applying
the model on each of the simulated rotating projections: 4893 CBCTs from
Synchrony data and 5262 CBCTs from Calypso data.
Results: Strong correlation of both LR and AP motion with SI motion was observed in the thorax/abdomen tumour data with the correlation coefficients ofabout 0.82 0.25, while the correlation coefficients in the prostate motion were0.28 0.22 and 0.38 0.29 for LR and AP, respectively. With the simple linear
model, mean 3D root-mean-square estimation errors were 0.41 mm and 0.28
mm for thorax/abdomen tumour and prostate trajectory, respectively. The errors were smaller than 1 mm for 90.8% of the thorax/abdomen trajectories andfor 98.8% of the prostate trajectories. Small improvement was achieved withthe state-augmented linear model for the thorax/abdomen tumour only: themean error/the percentage of smaller than 1mm error were 0.36 mm/93.6%
for the thorax/abdomen (Fig. 1).

1204 poster
REAL-TIME MR IMAGING STRATEGIES FOR TRACKING MOVINGAND DEFORMING LUNG TUMORS
A. Sawant1 , C. Hong2 , S. Preston3 , S. Joshi3
1
UT S OUTHWESTERN M EDICAL C ENTER, Radiation Oncology, Dallas, USA
2
YONSEI C ANCER C ENTER , YONSEI U NIVERSITY, Seoul, Korea Republic of3
U NIVERSITY OF U TAH, Scientific Computing and Imaging Institute, Utah,
USA
Purpose: It is well-recognized that lung tumors and surrounding thoracic
structures move and deform in a complex manner both inter- and intrafraction. However, current state-of-the-art techniques in motion managed
radiotherapy planning and delivery simplistically characterize this motion of
the irradiated volume (IV) as the rigid translation of a single point - usually,
the tumor centroid. In this work, we investigate the feasibility of using rapid
cine MRI as a non-invasive, soft-tissue image guidance tool to characterize
the real-time spatio-temporal evolution of the IV. The overall objective is to develop tools to enable more sophisticated 4D planning as well as 4D adaptive
delivery, e.g., using integrated MRI+Linac systems.
Materials: Under an IRB-approved protocol, two lung cancer patients wereimaged under free breathing conditions, without extrinsic contrast on a 1.5 T
MRI scanner. A balanced steady-state free precession sequence (b-SSFP;TE/TR: 1.68/3.16 ms; FOV: 240 x 240 mm2 , half-Fourier, voxel: 2.4 x 3 x
5 mm3 ) was used in conjunction with a 4-channel cardiac coil to image atime series (~12 s) of 2D coronal and sagittal slices.The same sequence wasalso used to acquire a time series of 3D volumetric images over ~60 s. An
optical fluid-flow-based deformable image registration was applied to eachtime series in order to map the trajectory of each voxel within the imaging
field of view (FOV). In each case, the motion of the tumor boundary, the tumor
centroid and the surrounding structures was analyzed in order to characterize
the degree of complexity of motion within the IV.
Results: The b-SSFP sequence yielded adequate signal-to-noise ratio forimage guidance and an acquisition speed of over 6 frames/s for 2D imaging- adequate for imaging most respiratory motion (typical resp. period: 3 to 6s). The 3D acquisition times were significantly higher - ~1.5 s/volume. In Patient#1, the motion of the tumor centroid was well-correlated with the motionof individual points on the tumor boundary (R2 from 0.9 to 1.0) as well as the
motion of the edge of the diaphragm (R2 = 0.99), indicating that there was no
significant tumor rotation/deformation. In Patient#2, likely due to the proximityof the cardiac wall, motion of the tumor centroid motion was relatively poorly
correlated with that of the boundary (R2 from = 0.6 to 0.94) and very poorly
correlated with diaphragmatic motion (R2 = 0.16), indicating the presence ofsignificant rotation and deformation.

Conclusions: Rapid cine-MRI is a feasible tool that can give non-invasive,
soft-tissue-based image guidance for lung cancer radiotherapy. The lackof ionizing radiation (e.g., as opposed to 4D CT) enables monitoring theanatomy more frequently and for longer. As seen from the results, such monitoring enables us to more accurately characterize the 4D spatio-temporal
evolution of the irradiated thoracic volume.
1205 poster
SUB-MM ACCURATE ESTIMATION OF 3D TARGET TRAJECTORYFROM CBCT
B. Cho12 , P. Poulsen3 , P. Keall4
1
A SAN M EDICAL C ENTER, Seoul, Korea Republic of2
U NIVERSITY OF U LSAN C OLLEGE OF M EDICINE, Department of Radiation
Oncology, Seoul, Korea Republic of3
A ARHUS U NIVERSITY, Department of Oncolory, Aarhus C, Denmark
4
U NIVERSITY OF S YDNEY, Radiation Physics Laboratory, Sydney, Australia
Purpose: With wide use of CBCT in IGRT, extracting the 3D target trajectoryfrom CBCT projection images would be useful to manage intra-fraction motion
for motion inclusive, gated and tumour tracking delivery methods. The purpose of this work was to develop a target trajectory estimation method from
CBCT by employing inter-dimensional correlation between each direction oftarget motion, and evaluate its performance in a simulation study.
Materials: To estimate the target trajectory we utilize the inter-dimensionalcorrelation between each direction of target motion that has been demonstrated for thoracic, abdominal and prostate tumours. In the CBCT rotating
projection images, the superior-inferior (SI) target position is resolved for all
imaging angles, while the left-right (LR) or anterior-posterior (AP) positions
are resolved only in a specific angle. In this work, the unresolved LR or
AP motion component was assumed to be linearly correlated with the resolved SI motion. Two linear models were applied: 1) simple linear, LR(t) [orAP(t)] = a*SI(t)+b, and 2) state-augmented linear model, LR(t) [or AP(t)] =Figure 1. Histograms of 3D rms estimation error for Thorax/abdomen tumour trajectories in the (a) simple, (b) state-augmented linear model, and for
Prostate trajectories in the (c) simple, (d) state-augmented linear model.
Conclusions: The 3D target trajectory can be successfully estimated withinclinical accuracy requirements by applying a position estimation method
based on inter-dimensional correlation. The method is applicable to motion
inclusive, gated and real-time tumour tracking treatments.
1206 poster
SUSCEPTIBILITY OF INTENSITY MODULATED (ARC) THERAPIESON MORPHOLOGICAL CHANGES IN THE HEAD AND NECKREGION.
P. Winkler1 , G. Lodron2 , H. Mayer2 , M. Uray2 , G. Jakse1 , R. Flitsch1 , B.
Zurl1 , K. Kapp1
1
M EDICAL U NIVERSITY OF G RAZ, Department of Therapeutic Radiology
and Oncology, Graz, Austria
2
J OANNEUM R ESEARCH, Institute for Information and Communication
Technologies, Graz, Austria
Purpose: Morphological changes during a radiotherapy course are known tohave a significant impact on the dose distributions, namely for treatments in
the head and neck region. Aim of our study was to analyze, whether these
dosimetric changes are more severe in intensity modulated treatment techniques static IMRT and volumetric modulated arc (VMAT) - as compared toconventional 3D-conformal treatment plans.
Materials: In an associated clinical study patients treated with neoadjuvant
radiotherapy (IMRT) for carcinoma in the H&N region, were repeatedly CTscanned during their RT-course. For the purpose of this dosimetric study 3treatment plans covering the primary target volume (PTV1) were created for
10 of these patients: conventional (3D-conformal), IMRT with fixed gantry position (Pinnacle3 DMPO, Philips) and VMAT (RapidArc, Varian and SmartArc,
Philips). A software tool for deformable image registration (DIR) and contour
propagation was developed, enabling us to adapt delineations to the changing morphology, transfer them to the consecutive CT-scan and thus to analyze
volumetric changes quantitatively. Initial treatment plans were transferred tothe consecutive CT-scans without re-optimization, to get an estimate of theinfluence of morphologic changes on dosimetry.Mean dose, D2%, and D98%
values (dose received by 2% and 98% of the volume) were analyzed for theS 450

IGRT: B REATHING ADAPTED R ADIOTHERAPY

IGRT: B REATHING ADAPTED R ADIOTHERAPY

target volume, parotid and submandibular glands. Maximum dose and D2%
were analyzed for the spinal cord.
Results: At the time of repeated CT-scanning the patients had received 36Gy.
The mean relative changes in volume were -5% (PTV) and -17% (salivary
glands). A subgroup was identified showing distinct tumor shrinkage of 16% (PTV-volume) in average. Mean dose to the PTV increased by only
0.7% (conformal), 1.2% (IMRT), and 1.2% (VMAT). For the subgroup thesechanges were 1.0% (conformal), 1.8% (IMRT), and 1.9% (VMAT). The D98%
value decreased by 1.6% (conformal), 4.3% (IMRT), and 4.0% (VMAT). Severe changes were found in the maximum dose to the spinal cord: +2.0%(conformal), +13.9% (IMRT), and +13.7% (VMAT). Mean dose to parotid
glands changed by 5.0% (conformal), 6.4% (IMRT), and 6.3% (VMAT).

Figure: IMRT plan for the initial CT (left); automatically (DIR-based) propagated PTV-contour and dose calculation (95%, 80% and 60% isodoses) for
unchanged transferred plan-setup.
Conclusions: Our DIR-algorithm proved to be a valuable tool for contourpropagation and analysis of morphologic changes. The investigated groupof patients showed significant shrinkage of PTV and salivary glands. Nevertheless, the observed dosimetric impact was limited in general (figure). Intensity modulated treatment plans are slightly less robust to these influences,compared to conformal plans, in terms of PTV mean dose and coverage. A
considerably higher shift was found in the dose to organs at risk, namely the
spinal cord. Again IMRT and VMAT plans exhibited a higher susceptibility tomorphologic changes.

(SD ±201.8) (range 49.3-631.7 cm3 )Trend line assessments suggest thatrate of loss for the overall cohort is 28.4cm3 /week and with further subclassification suggesting a loss of 31.0 cm3 /week with weeks 1 and 5 CT
regime and 66.9cm3 /week with weekly CT.Mean volume change data for thecohort are presented in Figure 1.

Conclusions: Use of volumetric imaging throughout treatment provides essential information that planar imaging cannot, particularly with regards to aneck volume assessment re-planning strategy. Despite dietetic support thesepatients are likely to lose weight but this is not as relevant to dosimetry as
is volume change in the neck. Planning CT volumes are larger than at plancheck due to the effect of neo-adjuvant chemotherapy hydration and patient
weight loss prior to treatment start. The effect of CT hydration is also apparent in week 1.Further work is planned to look at the dosimetric effect ofthese volumetric changes within this cohort of patients. References:[1] MiahA, Bhide S, Guerrero T, Clark C, Newbold K-L, Harrington K and Nutting C.
Bilateral Superficial Parotid Gland Sparing IMRT Produces Similar Long-term
Xerostomia Scores when Compared to Unilateral Parotid Sparing IMRT in
Midline Head and Neck Squamous Cell Cancers (HNSCC). IJROBP 2009 75(3) S401[2] Hansen E, Bucci M, Quivey J, Weinberg V and Xia P. Repeat CT
imaging and re-planning during the course of IMRT for head-and-neck cancer.
IJROBP 2006 64 (2) 355-362

1207 poster
TOWARDS ADAPTIVE RE-PLANNING OF H/N IMRT PATIENTS: AN
AUDIT OF THE CHANGE IN ‘NECK’ VOLUME DURING TREATMENT.
S. A. Moinuddin1 , M. Kilkenny2 , P. Davies2 , V. Rompokos2 , I. Rosenberg2 ,G. Royle3 , D. Carnell2 , R. Mendes2
1
U NIVERISTY C OLLEGE L ONDON H OSPITALS NHS F OUNDATION T RUST,
London, United Kingdom
2
U NIVERSITY C OLLEGE H OSPITALS NHS T RUST, London, United Kingdom
3
U NIVERSITY C OLLEGE L ONDON, London, United Kingdom
Purpose: H/N patients benefit greatly from IMRT which produces highly conformal target dose distributions whilst avoiding structures such as the brainstem, spinal cord and the parotid glands [1]. However, many patients experience changes in their neck volume due to factors such as the resolution of
post-operative changes, weight loss and reduction in volume of the tumour
and/or nodes [2]. This has the potential to alter the prescribed dosimetry byover dosing critical volumes whilst under dosing target volumes. At University
College Hospital (UCH), London it is standard practice to acquire a CBCT
prior to the start of treatment (plan check) and weekly thereafter to aid in
set-up issues and inform the re-planning process. With this data readily available, a retrospective review of a cohort of patients was undertaken to assess
absolute volume change in the neck.
Materials: Sequential patients with oropharyngeal cancers treated between
July-September 2010 were evaluated.As per protocol, a plan check andweekly CBCTs were acquired using the Varian OBI system (Varian Medical
Systems,) with the Low Dose Thorax mode. [Scan diameter 45cm; Length
16cm]Within Eclipse (v8.9) an external structure set was created for each
CBCT and enclosed volume calculated. A further external structure set was
created on the original plan based around the Isocentre but copying the extent
of the CBCT. A volume was then created from this structure set.The volume
change between the plan data set and subsequent weekly CBCT scans werethen quantified.
Results: During this time period 11 patients were reviewed, 4 had concurrent chemotherapy (CT) weeks 1 and 5, 5 had weekly CT and the remainder no CT. A total of 13 planning scans (2 patients were subsequently replanned) and 69 CBCT scans were acquired. Missed CBCT scans were due
to scheduling issues (2), ill health (4) and reconstruction issues (2).Mean volume loss in the neck from planning scan to the end of treatment 303.0cm3

IGRT: Breathing adapted Radiotherapy
1208 poster
A NEW SOLUTION FOR IGRT IN SBRT OF LIVER LESIONS,BASED ON 3D US IMAGING COMBINED WITH ACTIVE BREATHINGCONTROL
E. Bloemen- van Gurp1 , S. van der Meer1 , P. Visser1 , J. Buijsen1 , I.
Steenbakkers1 , G. Lammering1 , F. Verhaegen1
1
M AASTRICHT R ADIATION T HERAPY AND O NCOLOGY (MAASTRO) CLINIC,
Maastricht, Netherlands
Purpose: The treatment of metastatic liver lesions is a relative new modality
in radiotherapy. To reduce the mean dose to normal liver, a stereotactic bodyradiation therapy (SBRT) technique is used. Tumor positioning is of major
importance in SBRT, because high radiation doses are delivered in a few
fractions. The use of electronic portal imaging (EPI) is not sufficient, because
organ motion is independent of bony anatomy. The use of MV Cone Beam
CT (CBCT) in these patients is also inadequate, due to the lack of soft tissue
information. KV CBCT results in a better soft tissue contrast, however, forimage guidance based on the liver lesion itself, it is still not suitable. The
aim of this study is to establish the use of 3D ultrasound (US) combined with
Active Breathing Control (ABC) for IGRT in liver lesions.
Materials: A 3D US device (Clarity, Resonant Medical, Canada) was investigated for IGRT in liver cancer patients. An US probe was redesigned to obtain optimal scanning and probe tracking conditions for IGRT of the liver. For
ABC we used the SDX system (DynR, France). The correlation between the
SDX signal and the respiration correlated CT (RCCT) breath-hold signal wastested. At the treatment planning stage (RCCT session) a reference US scan
was performed in mid-ventilation. US and mid-ventilation CT images werefused, the lesion was contoured and beams and isocenter from the treatment
planning system were imported. Prior to each treatment an additional US
scan in mid-ventilation was acquired to compare the current position of thelesion to its reference position. A misalignment results in a 3D table shift.

Irradiation was performed in free-breathing. With our current machines andthe high fraction dose, gating would result in unacceptable treatment times.
Results: Accurate IGRT of liver lesions is difficult due to breathing motion
during imaging. This blurs the images and decreases image quality. Using
additional structures in the liver as a surrogate can be an alternative when
the lesion is not clearly visible on the US through blurring of the image. Dueto breathing, however, the liver deforms and the relationship between thelesion and the surrogate changes. Furthermore, the treatment plan is basedon the 50% expiration CT images. Ideally, the IGRT method should guidethe lesion to the same position as the planned position. In this study wedemonstrated that the combination of US scanning and ABC, optimized ourimage quality, prevented differences in liver deformation and resulted in an
identical position during treatment planning compared to the image guidance
situation. The SDX breathing signal and to the RCCT breath-hold signal wererunning simultaneous and the 50% expiration points were at the same level.
A schematic overview of the procedure is illustrated in figure 1.

Conclusions: Accurate IGRT in SBRT of liver lesions, using US imaging in
combination with ABC is feasible. It enables a decrease of the set up margin
in this treatment.
1209 poster
ANALYSIS OF DAILY HEART DOSE DEVIATION FOR LEFT SIDED
BREAST CANCER PATIENTS TREATED WITH RESPIRATORYGATING
B. Zurl1 , H. Stranzl1 , P. Winkler1 , K. Kapp1
1
M EDICAL U NIVERSITY OF G RAZ, University Clinic of Therapeutic Radiology
and Oncology, Graz, Austria
Purpose: It has been shown that Respiratory Gating using a deep inspiration
breath-hold mode (DIBH) significantly reduces the heart dose in patients irradiated for left-sided breast cancer. This study investigated if variations of thebreathing amplitude over a course of radiotherapy may lessen the calculatedheart dose derived from planning studies.
Materials: So far 150 patients were treated with a Respiratory Gating System (RPM / Varian Medical Systems, Inc., Palo Alto, CA) which uses a marker
block placed on the thoracic wall and an infrared camera. With acoustic encouragement patients were supported to reach their maximum amplitude in
DIBH where a specific gate had been defined according to which the treatment beam was triggered. Two CT-scans with and without DIBH were generated and the dose to the heart calculated. The daily treatment sessions withbreathing curves and the set gate were stored. For 11 arbitrarily chosen patients the individual amplitude in each treatment session was retrospectively
analysed. The impact on the heart dose for maximum and mean deviations
was determined by recalculating the treatment plans.
Results: For 11 patients 250 breathing curves were analysed and the maximum deviation of the amplitude such as the distance of the normal breathinglevel versus the predefined gate measured. The maximum deviation was 11.7
mm (0.5 34.8 mm) whereas the mean deviation for all sessions was 0 mm(-2.7 2.8 mm) (Fig.1.). As a result the maximum amplitude deviation due
to set-up inaccuracies increased the mean heart dose about 24% from 1.66
Gy (1.1 2.6 Gy) to 2.07 Gy, whereas mean amplitude deviations showed no
influence on the mean dose. The mean percental heart volume with 20 Gy(V20) increased from 3.36 ccm to 6.4 ccm. Maximum deviation for a single
session could result in tripling the heart dose.

Fig.1. Left: Breathing curve with measured amplitude and gate for the triggered beam. Right: Set-up deviations of the breathing amplitude in 2 patients.
Reference amplitudes were 20 and 25 mm.

S 451

Conclusions: Treatment sessions with a RPM Gating System in a DIBH
mode for left-sided breast cancer showed major variations in the daily setups regarding the normal breathing level versus breathing in the predefined
gate. If careful adjustments of the breathing amplitude are disregarded, thedose to the heart increases about 24%. Amplitude deviations of +/- 2mmshow no influence on the mean heart dose and are considered acceptable.
1210 poster
BREATHING ADAPTED RADIOTHERAPY USING OPTICAL REALTIME THORACIC LOCALIZATION
F. Nordström1 , R. Ljungqvist1 , S. Ceberg1 , C. Thornberg2 , S. Bäck12
1
L UND U NIVERSITY, S KÅNE U NIVERSITY H OSPITAL, Medical Radiation
Physics, Malmö, Sweden
2
S KÅNE U NIVERSITY H OSPITAL , M ALMÖ, Radiation Physics, Malmö,
SwedenPurpose: This work aims to investigate the properties of a laser based surface contour localization and monitoring system (Sentinel, C-Rad) with respect to its applications for breathing adapted radiotherapy (BART). Further,a visual coaching method was developed and evaluated in combination with
the Sentinel system.
Materials: A prototype version of the Sentinel Gating software was installed
in a clinical environment. This allowed comparisons with the present gating
system (RPM, Varian Medical Systems). Determination of the latency in thetwo systems was undertaken using a pneumatic piston that generated a visual binary signal. The time between the change in piston position and theoutput of a trig signal (e.g. release of beam hold) was measured using an
AVR microcontroller (Atmel). Localization curves for vertical treatment table
positions were acquired using the two systems simultaneously. The registered positions at different heights within ±1 cm were compared. Further, anapplication that converts the breathing-curve from the Sentinel system intoa single vertical bargraph was developed in order to allow visual feedback to
the patient. This method was compared with audio couching using 13 healthy
female volunteers utilizing the deep-inspiration breath hold (DIBH) technique.
Results: The latency in the systems was 192.1±16.5 ms and 118.6±56 ms
for the RPM and Sentinel system, respectively. For the Sentinel system, aplanned substitution of a relatively slow USB hardware component for thetrig signal would probably reduce the latency further. The stability of registered locations for the static vertical positions was in terms of average s.d.
0.04 mm and 0.15 mm for Sentinel and RPM, respectively. The maximum
difference between Sentinel and RPM registered position was 0.8 mm.The
reproducibility (mean of DIBH amplitude between DIBHs) was improved forall volunteers when the visual feedback was active. Six of the volunteers had
improvements between 1-2 mm and two more than 2 mm. The stability of theamplitude within one DIBH improved for three of the volunteers with 1-2 mm
and for one more than 2 mm.
Conclusions: The latency in the Sentinel is of a reasonable magnitude forgating purposes, and comparable with that of the RPM system. Sentinel
registered positions were very stable and in good agreement with those registered using RPM. The Sentinel system was found to be suitable for BARTand both the stability and the reproducibility of DIBHs were improved using
the developed visual coaching method.
1211 poster
COMPARISON OF TWO METHODS FOR FLUOROSCOPIC TRACKING OF TUMOR MASS
M. Schwarz1 , E. M. Stoiber12 , R. Bendl13
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
U NIVERSITY OF H EIDELBERG, Department of Radiation Oncology,
Heidelberg, Germany
3
U NIVERSITY OF H EILBRONN, Department of Medical Informatics, Heilbronn, Germany
Purpose: Precise lung tumor irradiation not only requires to correct for the
position of the target at the beginning of the treatment but also to gain information about the target trajectory throughout the treatment. The 2D trajectory can be obtained by acquiring planar fluoroscopic images during patient’s
breathing. Since implanting fiducial markers may not be widely accepted, we
prefer a marker-less method making use of registration techniques to extract
the tumor motion. Optical flow (OF) is a common approach in computer vision to detect motion in video. We present two approaches calculating the
OF in fluoroscopic video to track for tumor motion. The first approach uses
one reference image and the second uses multiple reference images.
Materials: OF associates the displacement that represents the distance a
pixel has moved between the previous frame and the current frame. In practice, calculating the sparse OF (tracking a subset of points) takes much lesscomputational cost than dense tracking. Here, the points to be tracked are
selected with a modified Harris Corner Detector [2]. To estimate the OF in theway Lucas-Kanade suggested [1], the terms of brightness constancy, temporal persistence and spatial coherence need to be fulfilled.For both of the two

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approaches first appropriate feature points are selected and then the OF between the reference image and the current image is calculated. The mediandisplacement vector is taken to indicate the motion of the tumor, assuming arigid transformation. The single template approach (ST) uses only one reference image. The multiple template approach (MT) uses so many reference
images, so that the tumor motion of the first in- or exhalation is covered insteps of maximal 5 mm. Therefore the tumor motion of these fluoroscopic
images needs to be defined manually. For calculation of the OF only thereference image with the highest correlation value to the current image isselected and then the motion vector is calculated analog to the ST approach.
Results: The MT method is capable to overcome errors that occur from intensity changes in fluoroscopic images acquired during breathing. Comparedto the ST approach, the error (mean ± SD) in longitudinal dimension canbe reduced from 0.6 ± 4.5 mm to 0.2 ± 0.9 mm (pixel size 0.8 mm). The
additional calculation time for MT compared to ST is less than 1 ms, when 5reference images are preselected.
Conclusions: We developed a registration technique based on multiple templates for directly tracking the lung tumor mass in fluoroscopic images to overcome intensity changes during breathing. The algorithm is sufficiently fast
and accurate to enable the implementation of adaptive strategies to compensate for respiratory motion. [1] Lucas and Kanade, An iterative image registration technique with an application to stereo vision, Proceedings of Imaging
Understanding Workshop 1981[2] Shi and Tomasi, Good Features to Track,
CVPR 1994
1212 poster
CYBERKNIFE SYNCHRONY TREATMENT EVALUATION: AN EXPERIMENTAL STUDY WITH HYSTERESIS MOVEMENT
M. S. Al Khawaja1 , V. Marchesi1 , D. WOLF1 , A. Noel1
1

IGRT: B REATHING ADAPTED R ADIOTHERAPY

IGRT: B REATHING ADAPTED R ADIOTHERAPYCRAN - C ENTRE A. VAUTRIN, Vandoeuvre-lès-Nancy Cedex, France

Purpose: The CyberKinfe is one of the most developed radiotherapy systems. With its subsystem synchrony, it allows us to treat the soft tissues
tumors that moving with reoperation, with the possibility of real time tracking.
This work aims to evaluate the system’s performance, in a special case of
respiratory motion known as hysteresis.
Materials: To achieve this work, the respiratory motion was simulated by our
dedicated mechanical platform, that was originally reconstructed to producta hysteresis sinusoidal movement, which can be defined as a difference ora separation between the inhalation and exhalation trajectory, the hysteresis movement is realized in the anterior-posterior/superior inferior plan asinternal movement of the tumors, with a special part to simulate the external movement of patient thorax. A cubic plastic ACCURAY phantom, withtwo Gafchromic films inserted in its central orthogonal (axial, frontal) plans,
was used to measure the total targeting error using the E2E ACCURAY software. RIT113 (V5.1) software was used to perform Gamma Index analysis(D%=4%, DTA=2 mm), with a prescribed dose of (480 cGy@ 80% Isodose).
A Perfection V700/V750 Epson Scanner was used to digitize the films.
Results: The geometric precision of tumor-tracking treatment with Synchron,which can also be called the total targeting error and which represents the offset between the centers of the delivered and the planed treatments are normally distributed (Shapiro-Wilk, Jarque-Bera, Anderson-Darling tests p=0.05
and µ=1.06 mm and σ 2 =0.131mm), with maximum value of 1.81 mm andminimum value of 0.43 mm. Gamma index results show show an high agreement degree between the prescribed and the delivered dose, with a numberof pixel (with Gamma>1) always lower than 5%.
Conclusions: This study has demonstrated the high precision of CyberKnife
treatment achieved with Synchrony tracking. The submillimeteric precision
can be guaranteed for treatments of moving soft tissue tumors in the caseof hysteresis respiratory movement, with a good matching between the prescribed and delivered doses.
1213 poster

to maximize distance between target volume and heart and minimize linac
treatment time. Patients were trained in DIBH at the CT appointment. Both
DIBH and FB CT-scans were acquired for treatment planning (Eclipse 8.6,
AAA algorithm). The best plan was chosen for treatment and the FB plan
kept as back-up in case of DIBH related technical problems or failing patientcompliance. CTV (breast, 5 mm under skin) and heart were contoured byoncologists on both CT-scans. PTV = CTV + 5 mm, not towards skin. As
compromises on target volume dose coverage to keep OAR dose low forsome of the clinical plans were necessary, a set of plans with 5 mm margin in
BEV from PTV towards lung were also made for investigation of heart sparing strictly related to DIBH. Plan normalization was 100% mean dose to CTV.
Prescribed dose was 2 Gy x 25.
Results: 17 of 20 patients were treated with DIBH (2/20 failed to acquire a
reproducible breathing pattern, 1/20 had equal heart dose but slightly higher
lung dose with DIBH). For the clinical plans, mean heart V25Gy was reducedwith DIBH (0.3% vs 1.6%). The mean DIBH heart doses were also lower
than FB for the 5 mm plans: V2Gy (11.6% vs 19.5%), V5Gy (2.0% vs 5.9%),
V10Gy (0.9% vs 3.7%), V20Gy (0.5% vs 2.7%), V25Gy (0.5% vs 2.4%),
V30Gy (0.4% vs 2.1%), D2cm3 (13.8 Gy vs 34.8 Gy). In BEV fewer patients
had overlap between PTV and heart for DIBH than FB (5/20 vs 14/20). Lung
dose was slightly reduced for DIBH compared to FB, ipsilateral mean dose
(6.6 Gy vs 7.1 Gy) and V20Gy (5.9 Gy vs 6.6 Gy). Target volume doses wereequal for DIBH and FB plans, PTV mean median dose (99.8% vs 99.9%) andD98% (94.0% vs 93.9%). Global maximum doses were also comparable for
DIBH and FB, D2cm3 (104.9% vs 104.6%).
Conclusions: DIBH is an effective method for reducing cardiac dose to very
low levels without compromising dose to target volume in radiotherapy of left
sided breast cancer and is now in routine use in our clinic. Methods for determining which patients will benefit most from DIBH should be explored to
optimize use of resources. Data on safe cardiac dose levels are needed.
1214 poster
DETERMINATION OF TUMOUR-CENTRE MOTION DURING A
CONE-BEAM CT ACQUISITION – A FEASIBILITY STUDY
J. Martin1 , J. McClelland1 , D. Hawkes1
1
U NIVERSITY C OLLEGE L ONDON, Centre for Medical Image Computing,London, United Kingdom
Purpose: Given phase-stamped cone-beam CT projections with marked tumour centres, a method is presented to calculate the average trajectory of
the tumour centre and position at the time of each projection. This method isintended to be used in conjunction with an automatic tumour detection algorithm, and reduce effects of errors incurred during the detection process. The
goal is to provide the clinician with a more accurate way of assessing tumour
location and motion trajectory on the day of treatment.
Materials: Each projection has an associated line connecting the tumour
centre and respective source positions in the patient 3D space. Each of thelines will intersect a plane at particular points. Grouping them into a seriesof complete breath cycles, these lines form loops on the plane. The optimal
position of the plane is computed that maximises similarity between loops.
This is done by minimising the sum of squared distances between predicted
3D positions at each phase.An average loop was constructed by finding themean of the predicted 3D positions for every phase value. An estimate of the
3D position at the time of each projection is simply the intersection between
the plane and respective line.
Results: A series of planar motion paths were simulated, based upon actual
respiratory motion variability from the literature. Normally distributed noise
within ±1mm and ±5mm were simulated for tumour centres in each projection, and represent errors in identification of tumour centres.The most extreme example of tumour motion had an RMS norm of 23.8mm (SuperiorInferior 15.9, Anterior-Posterior 14.6 and Left-Right 10 respectively). The algorithm was able to predict an average trajectory to within 2.0mm and 0.5mm
for 5mm and 1mm noise respectively. The full motion path predictions wereaffected more by noise, with errors of 5.5mm and 1.1mm respectively.

DEEP INSPIRATION BREATH HOLD REDUCES CARDIAC DOSE IN
IRRADIATION OF LEFT SIDED BREAST CANCER
M. H. Hansen1 , I. W. Ormberg1 , M. H. Jahr1 , Loe1 , A. Andersen1 , B. L.
Rekstad1 , E. Wist1 , J. B. Reitan1
1
O SLO U NIVERSITY H OSPITAL - U LLEVÅL, Oslo, Norway
Purpose: The heart is main organ at risk (OAR) in radiotherapy of left sided
breast cancer. Cardiac dose depends on factors such as patient anatomy,
target volume size and position, irradiation technique and dose constraints
for target volume and OAR. The dose levels for late radiation induced cardiac
events are not well established, neither the importance of different cardiac
sub structures. The aim of the study was to investigate patient complianceto deep inspiration breath hold (DIBH) and quantify heart sparing compared
to standard free breathing (FB) in tangential irradiation of left sided breast
cancer.
Materials: Breathing adapted radiotherapy using Varian RPM system wasintroduced in the clinic starting with 20 left sided breast cancer patients receiving tangential breast irradiation. DIBH was chosen as gating technique

1215 poster
MONITORING LUNG TUMOR MOTION BY REAL-TIME 2D/3D
REGISTRATION
C. Gendrin1 , C. Weber1 , C. Bloch1 , M. Stock2 , D. Georg2 , M. Figl1 , H.
Bergmann1 , W. Birkfellner1
1
M EDICAL U NIVERSITY OF V IENNA, Center for Medical Physics andBiomedical Engineering, Vienna, Austria
2
M EDICAL U NIVERSITY V IENNA , AKH, Department of Radiotherapy,
Vienna, Austria
Purpose: In Image Guided Radiation Therapy, intensity-based 2D/3D registration provides a method for the determination of setup deviations while
avoiding implanted devices such as gold markers or transponders. Nowadays, X-ray images can be acquired at a speed rate of about 5 Hz duringdose delivery thanks to on-board imaging units allowing for real-time patient
position but also for tumor motion monitoring. In this paper, we investigate
the possibility to use x-ray based real-time 2D/3D registration for lung tumor
motion monitoring during radiotherapy.
Materials: Our 2D/3D registration procedure uses general purpose massive
parallel computing device (GPGPU) programming techniques to render thedigitally reconstructed radiographs (DRR) and mutual information (MI) merit
function. First, the registration scheme is tested on CBCT and x-ray imagesof a phantom consisting of a cylinder translating along one direction. Then
five clinical patient data sets with CBCT, CT and x-ray images are used for further validation. For each patient, the planning CT is registered off-line to the
x-rays. The registration is performed using a region of interest (ROI) on the
x-ray defined by the 2D projection of the planned target volume (PTV). The
registration is performed using five degrees of freedom since the displacement along the beam axis cannot be resolved with 2D projection geometry.
After each registration, the motion parameters are extracted, allowing for theestimation of tumor motion.
Results: Figure 1 shows the results obtained for the phanton and a representative patient data set. The phantom translational motion of 20 mm is accurately measured. For the patient data set, a sinusoidal movement of about
3 Hz clearly correlates to the breathing cycle. The peak to peak displacement
is of 4 mm for the translation along x direction (superior-inferior motion), and
2 mm for the translation along y direction (left-right motion). For the other patient data sets, depending on the tumor site, displacements in the range 1 mm
to 7 mm are also observed. Videos demonstrate also a good match between
the x-ray images and the corresponding registered DRRs. Mean registration
time is 2 Hz.

Conclusions: In our experiment we have demonstrated that real-time tumor
motion monitoring using image based techniques is feasible. Registration
time might be further reduced by optimization and parallelization of the program. Future work will include the on-line implementation of the registration
set-up, and testing in a clinical setting.
1216 poster
PATIENT SELECTION CRITERIA FOR RADIOTHERAPY OF LEFTSIDED BREAST CANCER WITH RESPIRATORY GATING
K. I. Dybvik1 , M. H. B. Hjelstuen1 , I. Mjaaland1 , K. Iversen1 , J. Vikström1
1

S TAVANGER U NIVERSITY H OSPITAL, Department of Hematology andOncology, Stavanger, Norway

Conclusions: The method presented is capable of calculating tumour centre position to a useful accuracy if the tumour centre can be identified towithin±1mm on each projection. Nearing ±5mm, errors decrease accuracy.
In all cases, the average tumour trajectory was a more reliable measure andfor most clinical applications may be the most useful. The author is currently
working on integrating the method with an automatic tumour identification algorithm and extending this technique to non-planar tumour trajectories.

Purpose: Cardiac disease and pulmonary complications are documented
risk factors in breast irradiation. We have earlier demonstrated that irradiation of the left breast with or without regional lymph nodes included in thetarget volume, during deep inspiration, leads to a substantial reduction indose to heart and lungs without compromising target coverage. All patients
benefit from respiratory gating, but respiratory gating is not necessary for everyone to be in compliance with national guidelines for cardiac doses (VHeart,

S 453

25Gy>5%). In this study we were pursuing predictive factors that could act as
patient selection criteria for respiratory gating.
Materials: 17 patients with early breast cancer, referred for adjuvant radiotherapy, were included. Each patient underwent two CT scans; free breathing(FB) and deep inspiration breath-hold (DIBH). Treatment plans were made,focusing on adequate coverage (V95>98%) of the planning target volume(PTV). Plots of VHeart, 25Gy versus four thorax shape parameters, ipsilateral breast volume and total lung volume (TLV) were used to investigate if
there was any relationship between the parameters and to identify thresholdvalues that gave VHeart, 25Gy>5%.
Results: VHeart, 25Gy correlated with the TLV as increasing TLV gave decreasing VHeart, 25Gy . Preliminary analysis indicates a threshold TLV for
patients whose PTV did not include the regional lymph nodes of 2.0 litres
during FB. The threshold TLV for patients with PTV including the regional
lymph nodes was 2.6 litres during FB. No clear relation was observed between VHeart, 25Gy and the ipilateral breast volume or the four thorax shapeparameters.
Conclusions: Total lung volume during free breathing can be utilised as patient selection criteria for respiratory gating.
1217 poster
POTENTIAL CLINICAL BENEFIT OF IMRT, RAPIDARC AND RESPIRATORY GATING FOR LOCALLY ADVANCED NSCLC.
S. O’Keeffe1 , S. McNee1 , R. Muirhead2 , M. McJury1
1

T HE B EATSON W EST OF S COTLAND C ANCER C ENTRE, Department ofClinical Physics and Bio-Engineering, Glasgow, United Kingdom
T HE B EATSON W EST OF S COTLAND C ANCER C ENTRE, Glasgow, United
Kingdom

2

Purpose: Muirhead et al (2010)* reported that RGRT gave little benefit forlung dose parameters in a group of 15 patients with locally advanced NSCLC.
Following existing clinical practice, patients were planned with CRT using a
Pencil Beam (PB) dose calculation algorithm (Varian Eclipse vn 8.6). Our aim
was to investigate the gains that might be achieved with intensity modulation(IM) techniques (IMRT and RapidArc), with or without RGRT, using a type-b
dose calculation algorithm (AAA, Varian).
Materials: A retrospective analysis was conducted using Muirhead’s patientgroup i.e. node +ve with >5mm cranial-caudal respiratory movement. The
CRT plans were recomputed using AAA. IMRT plans were prepared using
6-ipsilateral fields (sliding windows) and RapidArc plans using 2 ipsilateral,clockwise and anti-clockwise arcs of 200◦ . Gated plans were based on endinspiration data. The PD was 55Gy in 20 fractions. Dose objectives for PTVs
were set as those achieved with AAA on the CRT plans. Lung DVH constraints were set at V5 < 50%, V10 <40%, V20 < 25%, V30 < 20%. Max
oesophagus dose was PD and s cord < 44Gy.
Results: For non-gated plans IMRT and RapidArc allowed significant,patient-dependent, improvements in lung V20 and MLD; see Table for dataon 3 representative patients. Monitor units were very much higher with IMRTand V5 results were mixed. Lung DVH constraints were readily met in somecases and so were further reduced; in other cases meeting constraints wasmore demanding. Max oesophagus dose changed little but mean oesophagus doses reduced on average by 10% with IM techniques.

S 454

IGRT: QA OF IMAGING DEVICES AND GEOMETRIC ACCURACY

IGRT: C ONCOMITTANT DOSE

V20 improved only slightly with respiratory gating: typically by 2%, MLD andV5 changes were larger but patient dependent.
Conclusions: Our work supports Muirhead’s conclusion that there is a limited gain in V20 from RGRT. The clearest gain may be achieved by using IM
techniques alone. This raises important and complex questions of how to optimise IM; how to set PTV and lung dose constraints; and the importance ofdose limits to heart and oesophagus, when dose escalation is to be considered. An important benefit might be to move patients with large tumours frompalliation to radical treatment strategy.

IGRT: Concomittant dose
1219 poster
A COMPREHENSIVE APPROACH TO CONE BEAM COMPUTEDTOMOGRAPHY DOSIMETRY
D. Scandurra1 , C. Lawford2
1
AUSTIN H EALTH R ADIATION O NCOLOGY C ENTRE, Heidelberg, Australia
2
P ETER M AC C ALLUM C ANCER C ENTRE, Melbourne, Australia

S 455

In the H&N the concomitant dose from repeated CBCT exposure can be lessthan 0.5 Gy. This is due to the lower X-ray energy used, and to lower mA
and ms values. Figure 1 shows the effect that concomitant dose can have inthe dose volume histogram of a lung patient, when added to the conventional
TPS plan.

1. Muirhead et al, Radiotherapy & Oncology, 2010 (95), 172-177.

1218 poster
TIME-CONSISTENT PARAMETRIZATION FROM DYNAMIC OPTICALSURFACE DETECTION FOR RESPIRATORY MOTION RECOVERYIN RADIATION ONCOLOGY
J. Schaerer1 , A. Fassi2 , M. Riboldi2 , G. Baroni2 , D. Sarrut1
1
C ENTRE L ÉON -B ÉRARD - CREATIS LRMN CNRS UMR5220 - INSERM
U630, Lyon, France
2
P OLITECNICO DI M ILANO U NIVERSITY, Bioengineering, Milano, Italy
Purpose: Optical surface tracking systems such as the VisionRT oer a simple
and non-invasive way to monitor the patient position during radiation therapy
treatments. However, these systems currently do not provide direct kinematic
information of specific anatomical landmarks if passive markers are not used.
Placing these markers on the patient can be time consuming or uncomfortable for the patient. In this work, we propose using deformable surface registration methods to robustly recover external patient motion, without relying
on markers.
Materials: We used the optimal step nonrigid ICP algorithm proposed by
Amberg et al. [1]. This algorithm uses shape features to gradually register a source surface onto a target surface. Using this algorithm, we register
the dynamic surfaces acquired during radiation therapy to a static acquisition in order to obtain consistently parametrized surfaces, from which motion
recovery is straightforward. Such information can be used to analyze thebreathing patterns of the patient, extract high quality breathing signals, detect irregularities or perform internal/external motion correlation.In order toassess the motion tracking accuracy of our method, we performed two experiments. The first experiment aimed to independently measure the accuracy
using a different modality (Cone-Beam CT) and a deformable phantom. To
this end, we placed 37 radio-opaque markers on a pillow, and imaged it withboth the VisionRT system and the CBCT in four different deformation states.
Motion between these states was independently derived from the VisionRT
surfaces using the proposed method, and from the CBCT using the location of
the automatically-segmented radiomarkers.The second experiment was designed to assess the method in a more realistic setting. To this end, 21 static
surface acquisitions were performed on five volunteers, with three different
breathing positions for each volunteer. Passive markers were placed on thethorax and abdomen of the volunteers and used to estimate the error.

Purpose: There is an increasing clinical need to assess patient dose from
CBCT in radiotherapy and as yet no consensus has been reached for an appropriate technique. A comprehensive method of quantifying CBCT dose has
been developed for use at this centre, incorporating point dose and integral
dose, to assess existing protocols and through a simple process allow prediction of dose for new protocols. It is expected that this technique will provide
a more complete description of the radiation burden to patients from frequent
CBCT imaging.
Materials: Measurements were carried out at Austin Health Radiation Oncology Centre, Melbourne, Australia, with an Elekta Synergy linear accelerator
with on-board CBCT. Two approaches to dose specification were used to render a more detailed representation of radiation absorbed by the patient. Point
dose measurements were performed according to AAPM’s TG-61 protocol,using a cylindrical ion chamber within a phantom, measured at various positions around the periphery and at the centre. Longitudinal dose profiles wererecorded using a linear diode array and acquired at the depths of absolutedose measurements. The profiles were normalised to absolute dose and integrated to provide DLPCBCT (mGy.cm). Using published conversion factors,
effective doses can be estimated.
Results: Using the linear response of dose to mAs, all point dose and DLP
results can be expressed per mAs. A dose prediction table is constructed withparameters per 100mAs, and sorted by collimator selection and image region.
This process was verified for existing CBCT protocols, where absolute dosefor head and neck, prostate and chest acquisitions range from 0.1 - 3.5 cGy,
DLPCBCT ranges from 27.5 653.0 mGy.cm with associated effective dosesof 0.1 11.1 mSv. These values correspond well to published literature. The
technique was subsequently used to predict doses for a new CBCT protocol
for anal IMRT that required large FOV and high soft tissue contrast.
Conclusions: A comprehensive method has been implemented that allows
a simple calculation to quantify dose from existing and new CBCT protocols
and provide a more detailed assessment of the radiation burden to patientsfrom frequent imaging. Point doses provide useful information but do notgive a complete description of patient dose. The combination of longitudinal dose profiles and absolute dose leads to a new metric, DLPCBCT, andthrough published conversion factors can be used to estimate effective dose.
A dose prediction table can be implemented where no new measurements
are needed to assess the impact of new CBCT protocols.
1220 poster
INCORPORATING CBCT CONCOMITANT DOSE IN TREATMENTPLANNING
E. Spezi1 , P. Downes1 , R. Jarvis1 , E. Radu1 , J. Staffurth2
1

V ELINDRE C ANCER C ENTRE, Department of Medical Physics, Cardiff,
United Kingdom
V ELINDRE C ANCER C ENTRE, Department of Clinical Oncology, Cardiff,
United Kingdom

2

Sample stereoscopic acquisition on a volunteer (left). The star-shaped markers are visible on the texture. The radius of the blue dots is equal to the normof the estimated motion. The figure on the right shows the mean error andstandard deviation for each acquisition on the volunteers.
Results: The average error was 2.9±1.6mm for the phantom experiment and1.8±1.3mm for the volunteers. We suspect the results were better for the volunteers because the human body has more shape features than the phantom
we used. Computation time was ~1min for a single surface registration. We
believe this could be significantly reduced by using a more local algorithm.
Conclusions: A new method for estimating time-consistent dynamic surface
parametrization from surfaces acquired with an optical tracking system waspresented. Further work includes working on the performance of the algorithm in order to make it run in real time, with possible applications to tracking
in radiation therapy.

Purpose: IGRT is the new paradigm in radiation therapy. With the increaseuse of on-board X-ray units in routine clinical practice, increased attention has
been given to the additional dose received by patients undergoing CBCT. In
this study we aim at incorporating the concomitant dose in treatment planning.
Materials: The CBCT used in this investigation was the Elekta XVI unit
mounted on a Synergy linear accelerator. A previously built Monte Carlo(MC) model of this unit [1-3] has been used to calculate the 3D dose delivered to patients undergoing CBCT. The concomitant dose has been calculated by simulating the full CBCT irradiation of a number of adult patients.
The combination of beam energy, collimator, filter, mA and ms was simulated accordingly to the imaging presets used clinically at our centre for eachanatomical site considered in this study. For the purpose of this investigation we calculated the additional dose delivered with an IGRT strategy that
included an average of 40 repeated CBCT scans during the course of a fractionated radiotherapy treatment. The calculated CBCT dose was added tothe planned dose for each clinical case and the total dose was re-evaluatedusing conventional plan evaluation metrics. The treatment planning system(TPS) used in this work was Oncentra MasterPlan (Nucletron). The engine
used for the calculation of the concomitant dose was the EGSnrc/BEAMnrc
Monte Carlo (MC) code.
Results: Our results show that during the course of treatment, for the IGRT
strategy that we selected and the imaging parameters currently used in ourcentre, the average additional dose from CBCT to bony structures can vary
between 1 and 2.5 Gy in the pelvis region. Additional dose to the PTV is in
the range: 0.5-1.2 Gy. In the chest, the additional dose to the PTV can be
between 1 and 2 Gy. Organs at risk can receive an extra dose of up to 2 Gy.

Conclusions: For the 200◦ degree scans the "scIMRT" method does not
result in an acceptable target dose distribution and therefore the "optIMRT"
method should be preferred, whereas for the 360◦ scans both methods could
be used. Which method results in the best sparing of the normal tissue
strongly depend on the location of the tumour and the relative position of the
OARs with respect to the tumour. E.g. for head cases short scans using "optIMRT" are the best suited with a scan range depending on the location of thetumour. Further evaluations using additional isodose volumes or biologicalmotivated quality indicators will be evaluated.

IGRT: QA of imaging devices andgeometric accuracy
Figure 1. A: PTV DVH for prescribed dose () and total dose including CBCT(–). B: OAR DVH for Cord-prv (o) Lung (x) and Heart (>).
Conclusions: In this work we have evaluated the concomitant dose delivered
to a range of patients undergoing CBCT. Our study has shown that it is feasible to include this data in the treatment planning process and that patient specific concomitant dose can be properly accounted for, through conventional
plan evaluation metrics.References1. Med Phys. 2009 Jan;36(1):127-36.2.
Phys Med Biol. 2009 54(7):N93-N100. 3. Med Phys. 2009 36(9):4156-67.
1221 poster
INCORPORATING IMAGING DOSE TO THE TREATMENT DOSE IN
IGRT – A COMPARISON OF 200°AND 360°MV-CBCT SCANS
A. Schwahofer1 , S. Nill1 , U. Oelfke1 , B. Rhein1 , A. Zabel-du Bois2
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Division of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
U NIV.
K LINIKUM H EIDELBERG, Department of Radiation Oncology,
Heidelberg, Germany
Purpose: In order to incorporate the imaging dose of MV CBCT to the prescribed treatment dose, 200◦ and 360◦ scans have been compared concerning target coverage and normal tissue sparing for four different body regions.
Materials: 18 clinical data sets representing four different tumour entities
were chosen. For all patients the IMRT based treatment was combined withdaily IGRT. To find the most suitable MV-CBCT for each body region one
360◦ full scan and three different 200◦ short scans were tested with following ranges: a) 180◦ ◦ ("short a"), b) 340◦ 0◦ ("short b"), c) 270◦ 0◦("short c"). The MV-CBCTs were simulated as gantry rotations inside the
TPS. For both, the 360◦ scans and the 200◦ scans, the MV CBCT protocols
comprised the same amount of Monitor Units. The following methods were
evaluated: "scIMRT": A scaled IMRT plan was created by renormalizing theoriginal IMRT plan in such a way that the sum with the MV CBCT dose yields
the same prescribed dose as the "orgIMRT" plan. "optIMRT": A newly optimized plan was generated by including the dose distribution of the MV CBCT
as pre-irradiation. The evaluation of the resulting dose distributions refers to
the original delivered IMRT plan "orgIMRT" without any additional imaging.
For the comparison of the target dose distribution the homogeneity index HI(Dmax/DRx) of the target volume was used. To evaluate the impact on thenormal tissue the volume enclosed by the 10%-isodoseline and the meandose to one organ at risk (OAR) for each entity were used.
Results: Including the additional delivered dose of a 200◦ scan using the"scIMRT" method leads to a significantly increased HI value for all indications
whereas for the 360◦ scans only a minor change is observed. If the "optIMRT" method is used the HI values can be improved but do still not reachthe same target dose distribution as for the 360◦ degree scan. The dose delivered to the normal tissue evaluated using the volume enclosed by the 10%
isodoseline (Table 1) is reduced for the 200◦ short scans as compared to the360◦ scans. The mean dose to the OARs is increased by about 8% with
"scIMRT" (6% "optIMRT") on average for the 360◦ scans and for the 200◦
scans about 14,4% with "scIMRT" (2,2% "optIMRT") on average over all entities and ranges.Table 1: Percentage difference of the homogeneity index HI
and the volume of the 10%-isodoseline (values are the mean values over allcases for each entity)

1222 poster
A 3-D FIDUCIAL PHANTOM TO ASSESS END-TO-END TOLERANCEFOR IMAGE GUIDED RADIOTHERAPY TREATMENT VERIFICATION
G. Heyes1 , S. Manolopoulos1 , P. Massey1 , A. John1 , E. Southgate1 , A.
Zarkar1
1
H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Birmingham, United Kingdom
Purpose: A 3-D purpose built cast acrylic phantom containing three obliquelyplaced gold markers has been designed in order to investigate the end-toend tolerance of Image Guided Radiotherapy (IGRT) using fiducial markers.
The phantom can be used for daily linear accelerator quality assurance, anddemonstrated a positional uncertainty of less than 2.0mm from planning CT
to the final treatment position verified with cone beam CT (CBCT).
Materials: Three 1.2x5mm gold markers (QLRad through OIS Ltd) havebeen placed at patient realistic positions (angled to the horizontal) within a
49mmx50mmx50mm delrin cube. The delrin cube is then itself set within alarger 149mmx148mmx150mm cast acrylic cube, at a fixed position offset
from centre. A CT scan (Philips Brilliance) is then taken of the phantom, anda planned (MV) isocentre set to be the centre of the delrin cube containing
the gold markers (CMS XiO). The phantom is set up on the treatment couchand the MV isocentre aligned to the centre of the acrylic phantom. A CBCT
(Elekta Synergy) of the phantom is acquired, and the CBCT images matchedto the planning CT data in order to calculate the necessary shifts for matching the fiducial markers (gold seeds). This is then compared with the known
offsets of the markers to indicate the accuracy of the IGRT system. A further
CBCT scan following automatic couch corrections could be used to calculate
residual errors. Implementing this shift enables a daily test of the true end-toend accuracy of positional uncertainty from CT to treatment position for IGRT
based on fiducial marker matching. The ability of the system to cope withrotational offsets can also be investigated by introducing a tilt, pitch and yaw
to the acrylic cube on the treatment couch.
Results:
Conclusions: The nature of this phantom also enabled a study to be madeof the set-up precision achievable using MV planar imaging (iViewGT) andcomparison with orthogonal digitally reconstructed radiographs. It has also
been used to determine the optimum slice width for CT to reduce image artefacts within the images and digitally reconstructed radiographs (DRRs) created within the treatment planning software. Image registration software has
also been investigated, with the matches achievable using MOSAIQ (Elekta),
iViewGT (Elekta) and PIPs (Standard Imaging) compared. Finally, the set-up
with this method encompass uncertainties from the whole treatment chain ina radiotherapy process (CT lasers and CT reconstruction algorithm, partial
volume effects and image artefacts, kV-MV isocentre alignment, CBCT reconstruction, image matching and shift calculation, couch shift accuracy etc.)
rather than individual components of the radiotherapy chain, normally verified
with a routine Quality Assurance programme. Thus, it is an invaluable tool for
setting up an IGRT process using CBCT, easily adopted as part of the daily
QA checks (time burden < 15 mins) and more importantly it helps boost theconfidence in implementing a new IGRT service. Reference:
1. H. McNair et al., "A comparison of the use of bony anatomyand internalmarkers for offline verification and an evaluation of the potential benefit
of online and offline verification protocols for prostate radiotherapy" Int.
J. Radiation Oncology Biol. Phys., Vol. 71, No. 1, pp. 4150, 2008.

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IGRT: QA OF IMAGING DEVICES AND GEOMETRIC ACCURACY

IGRT: QA OF IMAGING DEVICES AND GEOMETRIC ACCURACY1223 poster
CBCT COMMISSIONING: OPPORTUNITIES AND COMPROMISES
A. Reilly1
1

C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics Department, Bebington, Merseyside, United Kingdom

Purpose: A detailed characterisation of two Varian On-Board Imaging (OBI)
cone-beam CT (CBCT) systems was performed with a view to identifying objective performance metrics which could be used to guide optimisation exercises.
Materials: Images were acquired of the Catphan 504, CIRS 062A and inhouse phantoms using all available clinical protocols. The IQWorks image
analysis framework was utilised to analyse these, taking care to ensure theapproach followed was consistent with that specified by Varian yet also compatible with the methods widely employed for CT modalities in diagnostic
imaging.
Results: It was discovered that only two out of six clinical modes had beencalibrated by default, with the remaining modes having very different response curves. For some modes and materials these led to gross errors of
the order of 400 HU well outside Varian’s ±40 HU tolerance. Furthermore,
the gradients of the curves for different acquisition modes were considerably
different both in sign and order of magnitude. This compromised the relative
contrast observed between different materials and therefore had ramifications
for clinical image interpretation. Following calibration, all curves for all acquisition modes on both OBI units agreed sufficiently to assure dose calculation
accuracy within 2%. This is an important result because radiotherapy CBCT
systems tend to be entirely protocol driven and therefore it is essential these
protocols are optimised in advance of their clinical use. The importance ofutilising phantoms containing biologically representative materials for determining the electron density calibration curve is emphasised.Contrast to Noise
Ratio (CNR) and Modulation Transfer Function (MTF) measurements demonstrated a trade-off in object discriminability and spatial resolution with reconstruction matrix size: a boost MTF f50 of 2030% is achievable by using amatrix size of 5122 rather than 3842 , but with a corresponding reduction in
CNR of the order of 30%. These results will help inform clinical optimisation
exercises by indicating how performance might be boosted in support of particular clinical applications. For example, CNR might be sacrificed in favourof MTF when the goal is to localise high-contrast fiducial markers.
Conclusions: Being able to quickly and automatically undertake repetitive,
time-consuming analyses enabled comprehensive characterisation of all clinical imaging modes which would not otherwise have been possible. Furthermore, key performance factors were identified which must be consideredwhen optimising scan parameters for individual patient scenarios. In particular, the balance between MTF and CNR when choosing the image reconstruction matrix requires further consideration and consultation with clinicalusers. Elements of the commissioning process are being incorporated into a
UK audit of radiotherapy imaging being piloted during 2011. A brief summaryof the audit components is presented for discussion.
1224 poster
EVALUATION OF AUTOMATED IMAGE REGISTRATION ALGORITHM
AND ON-BOARD IMAGER FOR IMAGE GUIDED RADIOTHERAPY(IGRT).
D. Shamurailatpam1 , V. Mhatre1 , M. Heigrujam1 , S. Mallik1 , K. Talapatra1
1

KOKILABEN D HIRUBHAI A MBANI H OSPITAL AND M EDICAL R ESEARCHI NSTITUTE, Radiation Oncology, Mumbai, India

When only rotational error was introduced, the average rotational deviation inboth CBCTs was <±0.3◦ and 3D vector was ≤1 (0.94) mm. The increasein complexity of simulated error did not show increase deviation between detected and known offset excepting -1.2 (0.75) mm observed in Z direction for
CBCT_FF. The mean (SD) 3D vector in CBCT_FF and CBCT_HF for the combined translation and rotation error was 1.4 (0.65) and 0.3 (0.52) mm resp. In
all registration modes, the magnitude of the deviation does not appear to becorrelated with the magnitude of simulated error. The shifts did not show any
directional sensitivity. The automatic co-registration fails to detect simulated
error ≥20 mm in translation.
Conclusions: The automatic co-registration results showed sensitivity to inhomogeneity and structure shape within the selected ROI but insensitive todirection. The deviation between detected and known offset does not appear
to be correlated with the magnitude of simulated error. The overall accuracyof OBI system and co-registration software was satisfactory within 1.5 mm
and ≤0.3◦ .

Purpose: A cone beam CT scanner (CBCT) integrated with a linear accelerator needs to be calibrated to account for kV-to-MV isocenter misalignments
and gantry angle dependent non-idealities. The flex calibration takes approximately 1 hour. Recalibration occurs monthly to yearly depending on departmental qa program and after change of the position of the kV panel and X-ray
tube, or adjustments to the beam-line. We propose a new calibration procedure that aims to reduce the time needed while also providing a higher
accuracy.
Materials: The standard calibration procedure of Elekta Synergy to calibrate
the kV- to the MV isocenter works as follows. First, a Ball Bearing (BB) isisocentrically aligned to the room lasers. Subsequently, MV-images of the BB
are acquired at the gantry angles -180◦ , -90◦ , 0◦ and 90◦ , with 2 collimatorangles per gantry angle (-90◦ and 90◦ ). The average position of the BB
relative to the field edge is computed and misalignments exceeding 0.25mm are corrected by repositioning the BB. The procedure is repeated after
each correction. The kV isocenter is subsequently calibrated to the average
MV isocenter by acquiring fluoroscopic images over a full gantry sweep in
CW- and CC directions for all clinically used panel positions. The kV-flex
measurement is saved in a flexmap lookup table.In our new procedure, kV
and MV images are acquired simultaneously. Four arcs (2 CW- and 2 CC)
are required to obtain equivalent data. For each arc one fixed collimatorangle is used (from the set -90, 0, 90, 180). The MV flex (MVFU (parallel tothe plane of rotation, and MVFV (perpendicular to the plane of rotation)) iscaused by many machine related factors and the setup error (x,y,z) of the
BB. The BB position relative to the average MV isocenter can be computedfrom the MV flex by minimizing the equations below. Cone beam images
are acquired with the two clinically used panel positions in the CW- andCC rotation direction. The difference between the average MV flex and thegantry-dependent kV flex is determined per gantry angle and saved in a
lookup table.The advantages of our method above the Elekta method is we
do simultaneously acquisition of kV- and MV images, such that no additionaltime is required for determination of the MV isocenter and that we correct
directly for the setup error of the BB instead of repositioning the BB andacquiring MV images again.
180

Purpose: To evaluate the performance of image co-registration software for
automatically detecting and repositioning 4D offset of a phantom.
Materials: Patient treatment plan and set-up verification process was simulated on Catphan-504. The planed and machine isocenter was aligned precisely after correcting for residual error estimated from co-registration of reference planning CT with cone beam CT (CBCT) image of the phantom. Keeping this position as reference (X=0, Y=0, Z=0 and θ =0◦ ), set-up error was
simulated by introducing 3D offset ranging from ±5 mm to ±15 mm in all
three principal axes. For every simulated error, one set of orthogonal kV radiograph and two CBCT in half fan (CBCT_HF) and full fan (CBCT_FF) mode
were acquired. The orthogonal kV X-rays and CBCTs were automaticallyco-registered to reference DRRs and planning CT using 2D-2D and 3D-3D
matching software based on mutual information transformation. Investigation
was repeated by introducing only rotational error ranging from ±0.1◦ to ±1◦
in step of ±0.3◦ . A more complex situation was simulated by introducing
both translational and rotational errors. A total of 64 image sets (10 kV X-rays
pairs and 54 CBCT) were analyzed for the 37 simulated set-up errors.
Results: The automatic co-registration showed sensitivity to inhomogeneity
and structure shape of phantom present within user define region of interest (ROI). The data reported here was taken with ROI encompassing full
phantom image. For simulated translational error, the average deviation was<±0.5 mm in all three principal axes and <±0.2◦ rotation for 2D-2D and 3D3D matching except in CBCT_HF where an average deviation of -0.67 mm(SD=0.65) was observed in Y direction. The mean (SD) 3D vector was 1.7(1.1), 1.2 (0.8) and 1.4 (0.47) mm for kV-kV, CBCT_FF and CBCT_HF resp.

burg, Germany
G EORG AUGUST U NIVERSITY, Medical Physics and Biophysics, Göttingen,Germany31225 poster
FAST CBCT FLEX-CALIBRATION USING SIMULTANEOUS ACQUISITION OF KV- AND MV IMAGES
C. Panneman1 , J. J. Sonke1 , Y. Szeto1 , M. van Herk1 , P. Remeijer1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiotherapy, Amsterdam, Netherlands−180[MVFU(φ) − x sin(φ) − y cos(φ)] dφ−180[MVFV(φ) − z] dφ 180

Results: In figure 1, a typical example of MV- and kV flex is shown. With ourprocedure, the MV isocenter determination is max 0.25 mm more accurately
and the calibration time is reduced from approximately 1 hour to 30 minutes,
most of which can run unattended.

S 457

Conclusions: The new method is about 30 min faster, mainly because no
additional time is required for determination of the MV isocenter and because
the BB setup error is accounted for in software. This will also slightly improve
the accuracy of the calibration and subsequent guidance procedures.
1226 poster

Purpose: The physical and geometrical effects impairing the quality of portal images are characterized experimentally, and the combined effect is corrected by an iterative two-dimensional deconvolution algorithm, extending an
earlier 1D deconvolution.
Materials: Measurements were performed at an ARTISTE accelerator(Siemens). Blurring components were determined via the edge-spreadfunction (ESF). Assuming that the line-spread function (LSF) takes the formof a Lorentz function: 1/(1+x^2 + λ^2), each blurring component can be characterized by parameter λ. The measured image I(x,y) can be expressedas the convolution product of the two dimensional convolution kernel K(x,y)
and the true image I0(x,y). The iteration process consists in a sequence ofapproximations I0,n(x,y), converging towards the desired I0(x,y). Each approximation I0,n(x,y) is numerically convolved with K(x,y), resulting in an approximation In(x,y) to the blurred image. The next approximation I0,n+1(x,y)
is derived by adding to I0,n(x,y) the difference I(x,y) - In(x,y). The iteration
is terminated when the χ2-value for the difference between In(x,y) and I(x,y)
has become smaller than m .0001, where m and n are the dimensions of thematrix, hence allowing 1% deviation for each pixel.
Results: Geometrical penumbra, secondary electron transport in the EPID
and its pixel size are the major contributors to image blurring. Water phantom
measurements revealed that the scattering contribution is not significant. The
λ-values of the combined effects amount to 0.5 mm for 6 MV and 0.65 mm
for 15 MV. The deconvolution algorithm was tested using a line-pairs QCphantom. Fig. 1 shows the RMTF calculated before and after deconvolution.
Thereafter, the relative modulation transfer function (RMTF) was approaching
the one of an ideal detector. Enhancement of contrast and sharpness was
also observed on clinical portal images.

INVESTIGATING AN IMAGE GUIDED POSITIONING SYSTEM VIA
MV TREATMENT BEAM IMAGES
T. Hüpf1 , P. Winkler1 , K. Kapp1
1

M EDICAL U NIVERSITY OF G RAZ, Department of Therapeutic Radiology
and Oncology, Graz, Austria

Purpose: A clinical accelerator (Novalis Tx) equipped with the Brainlab ExacTrac (ET) positioning system was put into operation at our clinic in 2010.
We started an investigation to judge the accuracy of ET positioning. By using
treatment beam megavolt (MV) images for evaluation it is possible to obtainan integrative assembly which can numeralise the final positioning accuracy
and in addition can make the calibration free from adjustment uncertainties.
Materials: Firstly, an ET isocenter phantom intended as starting point for the
infrared and consequently x-ray calibration was adapted to enable MV treatment beam evaluation by drilling holes into the solid metal body in top-bottom
and left-right direction. Secondly, a human skull formerly used in medical education was equipped with a radio opaque marker (steel ball) placed at theforamen nervi optici acting as isocenter. Thirdly, a Winston-Lutz pointer ballcompletes the devices which are all closely connected to the QA procedures
already supplied by the ET software.The evaluation algorithm a modificationof a homemade software, first described in 2003 is based on segmentation
and analysis of MV images acquired with the EPID.
Results: The experimental steps can be organised with respect to two questions: 1. How precise can the ET system reproduce the calibration position,
2. what is the achieved accuracy in the treatment of a skull. The MV imagesof the Winston-Lutz pointer yield a gantry sag of about 0.35 mm between0◦ and 90◦ . Regarding 1, the ET positioning runs yield a statistic standard
deviation (std) of 0.13 mm (average of x, y, and z deviation). For the skull
positioned according to ET practice including head and neck hardware std is
0.07 mm. A consideration of the ’residual shifts’ (displayed by ET but inside
the accuracy tolerances) can lead to a decrease of std to 0.02 mm (in a 0.5mm CT scan). The absolute deviation (2.) turned out to be x: -0.36 mm, y:0.11 mm, and z: 0.77 mm.
Conclusions: The high precision of ET positioning may lead to a misinterpretation as ET can not cancel out errors committed earlier in the chain ofpatient treatment. Increasing the accuracy of a system is only possible with
devices that have feedback from the output or operate independently fromuncertain input. Apparently ET does exactly that, but both requirements are
missed! X-ray verification is not related to the treatment beam (output) andis strongly dependent on the calibration procedure which includes uncertain
input e.g. wall lasers. The assembly of this study is supposed to provide datain this context. However, ET positioning fits our setup very well as it does
not add significantly to the uncertainty budget which is dominated by otherinfluences.
1227 poster
MEASUREMENT OF PORTAL IMAGE BLURRING COMPONENTS
AND CORRECTION OF PORTAL IMAGES BY 2D-DECONVOLUTION
H. K. Looe12 , D. Harder3 , K. Willborn1 , B. Poppe12
1
P IUS - H OSPITAL, Radiation Therapy, Oldenburg, Germany
2
C ARL VON O SSIETZKY U NIVERSITY, Medical Radiation Physics, Olden-

Fig 1. RMTF of the QC-phantom before (circles) and after deconvolution. Triangles: iterations terminated by χ2-test. Squares: after at least 20 iterations.
Conclusions: The blurring effects of portal images were characterized andcorrected by an iterative deconvolution algorithm. The calculation per image
takes less than one minute. For better signal to noise ratio, it is recommended
to acquire images at a short focus-detector distance.
1228 poster
NOVEL 3D APPROXIMATE ENTROPY PARAMETER FOR QUALITYASSESSMENT OF CT/CBCT IMAGES
T. Marchant1 , C. Moore1
1
T HE C HRISTIE NHS F OUNDATION T RUST, North Western Medical Physics,
Manchester, United Kingdom
Purpose: To investigate the use of Approximate Entropy (ApEn) as a simple metric describing the degree of ordered structural information in noisy
IGRT data sources such as CBCT. ApEn is a regularity statistic previously
applied to 1D time series data, and capable of distinguishing degrees of regularity versus randomness (Pincus, 1991, Proc Natl Acad Sci USA 88 p2297).
This provides an alternative to traditional, variability-based statistics and has
proved useful in identifying different groups in medical data such as heart ratevariability analysis and speech quality after cancer treatment. In this work we
present a new extension of the ApEn concept to three dimensions (ApEn3D),
allowing ApEn to be calculated for an ROI centred on each voxel in a 3D image dataset. It is hypothesized that ApEn3D may prove useful in measuring

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IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

image quality of medical images by mapping the spatial variation of regularity
vs. randomness (i.e. the prominence of useful image information such asedges or regular textures).
Materials: In 1D, ApEn can be described as the likelihood that runs of datathat are similar over a certain comparison length, remain similar when thecomparison length is increased. In 3D we interpret "runs of data" centred
on a specific voxel as expanding outwards from the central voxel, rather thanbeing defined in a particular vector direction through the data. The second
element of a run is then comprised of the 26 surrounding voxels (first rim), thethird element consists of the 98 voxels in the second rim, and so on. Runs
are compared by considering the mean of the absolute differences between
the corresponding voxels of each element. ApEn3D processing was applied
to CT and CBCT images for pelvis and head and neck sites. This produces
an ApEn3D value at each voxel of the image which reflects the degree of
regularity in the image data around that point. Areas dominated by noise
have high ApEn3D values, while areas with regular data (e.g. edges, regular
texture) have low values. The distribution of ApEn3D values was compared
for CT vs. CBCT images and for CBCT images acquired at different doselevels.
Results: Figure 1 shows ApEn3D processed CBCT and CT images. A histogram of ApEn3D values in these images divides into a peak at high values(where noise dominates) and a tail at lower values. The proportion of voxels
falling outside of the noise peak (i.e. containing structure information) wasinvestigated as a quality parameter indicating image utility. CT images for aparticular site show consistently higher values for this parameter than CBCT
(e.g. pelvic images: 0.57±0.03 for CT vs. 0.44±0.06 for CBCT, based on
10 CT and 10 CBCT images). Head and neck CBCT of the same patientacquired at high vs. low dose (5.6mGy vs. 1.4mGy) show higher value for thehigher dose scan (0.60 vs. 0.43).

IGRT: Treatment delivery and patient positioning

1232 poster
ASSESSMENT OF LARYNGEAL DISPLACEMENT IN HEAD AND
NECK IMRT PATIENTS FOR CONSIDERATION OF ADAPTIVEREPLANNING UTILIZING CONE BEAM CT DATA.
M. Rolfo1 , N. Anderson1 , V. Khoo21 , M. Handley1 , D. Lim Joon1 , M. Wada1
1
AUSTIN H EALTH, Radiation Oncology, Heidelberg West, Melbourne,
Australia
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom

1229 poster
AN AUDIT OF THE USE OF IGRT IN THE UK INDEPENDENTSECTORK. sikora1
1
C ANCER PARTNERS UK, London, United Kingdom

Purpose: Previous institutional studies, utilising daily CBCT, to benchmark
an in-house stabilisation strategy, showed a consistently reproducible set up
across the regions of skull base, mandible, cervical spine and shoulder complex. However additional off-line assessment revealed laryngeal displacement in a small cohort of patients. A study was designed to determine theincidence of, and in this cohort, quantify the magnitude of laryngeal movement in IMRT head and neck patients.
Materials: The patients were stabilised using a customised half body cradle
extending from the head, supporting the neck and continuing below the levelof the olecranon processes and encompassing the upper arms and shoulders, together with the Civco IMRT Reinforced head and neck thermoplastic
mask. Daily Cone Beam CT’s were acquired, as per the institutional image
guidance protocol, using an Elekta Synergy Linear Accelerator All data sets
were analysed by three independent observers to identify residual laryngeal
displacement. A volume of interest (VOI) was placed around the larynx anddisplacement figures calculated using the automated bony match algorithm.
The daily distortional residual error was calculated with reference to a standard VOI placed around upper cervical vertebrae (C1-3), by subtracting thex,y,z co-ordinates of the larynx to the reference. Distortional statistics werethen summarised.
Results: A total of 93 patients and 2670 data sets were analysed.Of
the analysed patients, 9.7% were determined to have laryngeal displacement. This subgroup recorded a systematic displacement of 1.02mm in
Medio-Lateral(ML); 6.64mm in Cranio-Caudal(CC); and 1.23mm in AnteroPosterior(AP) directions. Similarly the random displacement was 1.00mm in
ML; 2.52mm in CC and 1.50mm in AP directions.
Conclusions: For IMRT head and neck planning and delivery, it is imperativethat accurate and reproducible patient immobilisation strategies are employed
and distortional set up variation is minimised throughout the entire treatment
course.Daily assurance in the maintenance of patient anatomical geometry
is an essential component for quality IMRT dose delivery. Using daily CBCT,
we recorded distortional movement of the larynx in up to 10% of cases withthe main component in the CC direction. This permits the development of an
adaptive schema including anistropic planning margins for the managementof these cases to ensure reliability and accuracy.

Purpose: The independent sector is now rapidly moving forward with novel
solutions by creating an independent network of private cancer centres
around Britain. CancerPartnersUK, a private equity funded cancer careorganisation has opened four centres between August 2009 and today inPortsmouth, Southampton, Elstree and Birmingham. Four more are underconstruction and will open this year. Our clinical protocol utilises Image
Guided Radiotherapy (IGRT) with every fraction during radical treatment.
Materials: The centres all use state of the art equipment with innovative planning tools for IMRT. We are delivering IMRT to 56% of our patients compared
to 10% in the NHS. A policy decision was madfe to use IGRT with every
fraction from the start. This ensures pin point precision in radiotherapy delivery reducing the side effects caused by damage to organs at risk as well as
giving the therapist confidence in prescribing higher and potentially more efficacious doses. Each of our centres were constructed and became clinicallyoperational within 8 months of build start.
Results: We have collated the IGRT data on our first 500 patients and can
now assess the likely benefits of IGRT. A couch shift was made in 91% of
fractions and an iso-centre shift made in 15% of treatments during a completed course. Details of the number and magnitude of the changes will bepresented.
Conclusions: Web enabled distance computer planning has led to more efficient ways of working including consultant sign off of plans from remote locations and cebntralised planning for even complex treatments. We plan toexpand our network rapidly both in the UK private and public sectors as wellas using the model to improve the quality of radiotherapy in several international locations.
1230 posterAN
ENDORECTALBALLOON
REDUCESINTRAFRACTIONPROSTATE MOTION DURING RADIOTHERAPY
11
2
2
R. J. Smeenk , R. Louwe , K. Langen , A. Shah , P. Kupelian2 , E. van
Lin1 , J. Kaanders1
1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Department ofRadiation Oncology, Nijmegen, Netherlands
2
MD A NDERSON C ANCER C ENTER O RLANDO, Department of Radiation
Oncology, Orlando, FL, USA

Conclusions: ApEn3D shows potential as an additional metric of image quality in noisy medical image data such as frequently encountered in IGRT.

Purpose: To investigate the effect of endorectal balloons (ERBs) on intrafraction and interfraction prostate motion during radiotherapy.
Materials: 30 patients with localized prostate cancer were treated withintensity-modulated radiotherapy, to a total dose of 80 Gy in 40 fractions.
In 15 patients, a daily-inserted air-filled ERB was used during treatment. The
prostate motion was tracked in real-time using an electromagnetic tracking
system. Manual table corrections, made during treatment sessions, were retrospectively undone before calculating the intrafraction displacements. These
displacements were analyzed in timeframes of 150 s, and displacements >1
mm, >3 mm, >5 mm and >7 mm were determined in the anterior-posterior(AP), left-right (LR), and superior-inferior (SI) direction, and for the 3D-vector.
Interfraction displacements were quantified by calculating the systematic andrandom deviations of the center of mass of the implanted transponders before
each treatment.
Results: 576 and 567 tracks were analyzed in the No-ERB-group and ERBgroup, respectively. Interfraction variation was not significantly different between both groups. After 600 s, 95% and 98% of the treatments were completed in the respective groups. Significantly fewer table corrections were performed during treatment fractions with ERB: 88 vs. 207 (p = 0.02). For bothgroups, the intrafraction deviations increased with time, but 3D-intrafraction
deviations were significantly reduced for patients treated with ERB. After 600
s, this resulted in cumulative percentages of 3D-vector deviations >1 mm, >3
mm, >5 mm and >7 mm that were 57.7%, 7.0%, 0.7% and 0.3% in the ERBgroup vs. 70.2%, 18.1%, 4.6% and 1.4% in the No-ERB-group. Analysis of
the data for the individual directions showed that the largest reductions in the
ERB-group were observed in the AP direction (see figure). The data indicatethat intrafraction deviations are adequately accounted for within a CTV-toPTV margin of 7 mm, and 5 mm in the posterior direction, when an ERB is
used.

S 459

Conclusions: Application of an ERB significantly reduces intrafraction
prostate motion, but not interfraction variation, and may in particular be beneficial for longer treatment sessions.
1231 poster
AN INVESTIGATION OF BREAST IGRT IN EUROPE AND NORTHAMERICA AND THE CLINICAL IMPACT OF ITS IMPLEMENTATION
E. Gill1 , M. Coffey1 , M. Leech1
1
TCD D IVISION OF R ADIATION T HERAPY, Dublin, Ireland Republic ofPurpose: The aim of this study was to establish the use of and indications forbreast Image-guided radiation therapy (IGRT) in departments across Europe
and North America. The clinical impact of the implementation of IGRT was
also investigated.
Materials: A questionnaire based on a comprehensive review of the literature and reflecting the aims of the study was designed and circulated to radiotherapy departments in Europe and North America for completion by one
Radiation Therapist (RT).
Results: The results of this study show that while Electronic Portal Imaging
Device (EPID) remains the most commonly used imaging device for breast
treatment verification (94%), the use of Cone-Beam CT (CBCT) is growing. The target volume, the treatment planning technique and the treatment
schedule appear to be indications for the use of breast IGRT. With the implementation of IGRT, RTs felt that IGRT added to their responsibilities (M=2.57).
Responses indicated that IGRT had the least effect on work environment
stress and personal stress (M=1.37, 1.28 respectively). Additionally, the mostpositive response was in reConclusions: The results of this study indicate that breast IGRT has beenrealised in many departments across Europe and North America. The resultsappear to concur with the literature and the suggestions that breast IGRT
should be utilised for Partial Breast Irradiation (PBI), intensity-modulated radiation therapy (IMRT) and hypofractionated schedules. Overall, departments
seem to have made adequate provisions for the introduction of breast IGRT.
However, RTs felt that advanced imaging protocols added to their responsibilities.

1233 poster
AUTOMATIC +/- MANUAL CORRECTION FOR INTER-FRACTIONERRORS DETECTION IN PATIENTS TREATED WITH TOMOTHERAPY®
P. Antognoni1 , P. Barbieri1 , A. Bruni1 , E. Cenacchi2 , P. Ceroni2 , G. Guidi2 ,B. Lanfranchi1 , E. Mazzeo1 , B. Meduri1 , M. Parmiggiani1 , S. Pratissoli1 , G.
Tolento1 , E. Turco1 , T. Costi2 , F. Bertoni1
1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Radiation Therapy,
Modena, Italy
2
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Physics, Modena, Italy
Purpose: Tomotherapy® can perform megavoltage computed tomography(MVCT) imaging before treatment. This study aims to investigate differencesin terms of inter-fraction error detection between automatic vs. manual correction MVCT- kVCT matching
Materials: We evaluated data from 19 patients (pts): 5 Head & Neck and
14 prostate. MVCT was used to verify patient position and target localization before each treatment fraction. 3D translational lateral (LA), longitudinal(LO) and vertical (V) corrections were calculated using either the automaticbone-based (BO) and bone+tissue-based (BT) matching modality or manual
matching operated by physician correction after complete automatic matching. We also evaluated differences between inter-fraction errors by using
automatic bone-based or bone+tissue-based matching modality and manual
physician-operated matching. All measures were analyzed by Student’s ttest.
Results: For prostate cancer pts: the mean LA inter-fractional set-up difference between BO vs. BT method was 0.012 mm (SD=0.59), the mean LO
inter-fractional set-up difference between BO vs. BT was -1.2 mm (SD=1.37),
the mean V inter-fractional setup difference between BO vs. BT was 0.3(SD=1.05). The mean LA inter-fractional set-up difference between BO vs.
manual correction was 0.012 mm (SD=0.87). The mean LO inter-fractional
set-up difference between BO vs. manual correction was -0.43 mm (SD=0.7).
The mean V inter-fractional set-up difference between BO vs. manual correction was 0.19 mm (SD=2.36). The difference in terms of correction 3D factor(c3Df) between BO vs. BT method was 2 mm + 1 mm SD and 2.2 mm + 1.2
mm SD between BO vs. manual method. For Head & Neck cancer pts theS 460

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

mean LA inter-fractional set-up difference between BO vs. BT was 1.6 mm(SD=2.02), the mean LO inter-fractional set-up difference between BO vs.
BT was 0.15 mm (SD=2.10), the mean V inter-fractional set-up difference between BO vs. BT was -0.03 (SD=1.09). The mean LA inter-fractional set-up
difference between BO vs. manual correction was 0.25 mm (SD=1.47). The
mean LO inter-fractional set-up difference between BO vs. manual correction
was 0.92 mm (SD=1.53). The mean V inter-fractional set-up difference between BO vs. manual correction was -2.75 mm (SD=4.01). The difference interms of c3Df between BO vs. BT method was 1 mm + 0.66 mm SD and 1.02
mm + 0.81 mm SD between BO vs. manual method.
Conclusions: Our results, although derived from a small number of measurements, show that there are no statistically significant differences in interfractional set-up errors detection between automatic vs. manual correction
MVCT- kVCT matching procedures. These findings may be useful for workflow management, as the physician task might be limited to the evaluation of
doubtful cases or for those which result significantly out of standard-defined
cut-off parameters.

to-day positioning of the prostate and the bony anatomy using an integrated
CT-linear accelerator system for external beam radiation therapy for prostatecancer.
Materials: A total of 1176 pretreatment in-room CT images and digitally reconstructed radio-graph (DRR) pairs from 33 patients were acquired over thecourse of the study. The differences between the isocentre of the prostate
on in-room CT and the isocentre of the bony anatomy on DRR were analysed. The agreement between positions in each direction was comparedusing Bland-Altman limits of agreement.
Results: The 95% limits of agreement in lateral (LR), superoinferior (SI), andanteroposterior (AP) directions were -2.98 to 2.49 mm, -4.69 to 5.75 mm, and-8.23 to 7.30 mm, respectively. The isocentre was localised to within 3.0 mm
on in-room CT images and DRR 99.0% in LR, 85.1% in SI, and 85.9% in AP.

1237 poster
CONE BEAM CT STUDY OF PATIENT POSITION REPRODUCIBILITY
AND STABILITY USING DIFFERENT TYPES OF HEAD FIXATION
S. Koch1 , C. Floors-Stortelder1 , I. te Veluwe1 , C. Derkman - van de Laak1 ,E. van Dieren1
1
M EDISCH S PECTRUM T WENTE, Department of Radiotherapy, Enschede,
Netherlands

1234 poster
COMPARING INVESTIGATION OF REPOSITIONING ACCURACY
FOR HEAD AND NECK IMRT
D. Kawai1 , Y. Koizumi1 , H. Tachibana2 , Y. Itou3 , T. Satou3 , M. Satou4
1
KOMAZAWA U NIVERSITY, Radiology, Tokyo, Japan2
S TANFORD U NIVERSITY, Radiation Oncology, Stanford, USA
3
J APANESE F OUNDATION FOR C ANCER R ESEARCH , C ANCER I NSTITUTE
H OSPITAL, Radiation Oncology, Tokyo, Japan
4
KOMAZAWA U NIVERSITY, Radiation Oncology, Tokyo, Japan
Purpose: The first aim of this study is to investigate the patient repositioning
accuracy for Head and Neck IMRTIntensity Modulated Radiation Therapy in
our institute by comparing with the report by Rotondo et al. The second aim isto evaluate the changes of patients’ dose distributions in their normal tissues(spinal cord, brain stem, right parotis and left parotis) after 20 days from theday of their first treatment by using Equivalent Uniformed Dose (EUD).
Materials: Our shell system was composed of S-typeTM with Precise biteTM
mouthpiece. 9 patients with Head and Neck cancer undergoing IMRT wereanalyzed. Linac Graphy (LG) images were obtained by Electric portal imaging
device (EPID) during the course of radiation therapy (the median number of
LGs is 11 per a patient). 3 landmarks were defined in each LG image, whichwere the Upper landmarks, the Middle landmarks and the Lower landmarks.
The deviation between Simulator image and LG was automatically calculated by using off-line correction software, Off-Line Review (ARIA). Systematic error (simulation-to-treatment variability) and random error (treatmentto-treatment variability) were calculated. Total population displacement error
combines the contributions of both systematic error and random error. Total
3-D population displacement error indicates total population displacement error having the magnitude of the displacement in any spatial directions fromreference position. The total population displacement error for each direction
and the total 3-D population displacement error for each landmark were calculated by the systematic error and the random error. EUDs of both initial
treatment plan and 20 days-treatment plan were calculated by Dose Volume
Histogram (DVH) and were compared.
Results: The maximum of the total population displacement error for eachdirection was 2.5mm (1SD) for the lower landmarks. The maximum of the 3D total population displacement error was the largest in the lower landmarks,
which was 3.2mm (1SD). Comparing those value with the report by Rotondo
et al, the both errors in our institute were almost equal in the upper and the
middle landmark, and were smaller in the lower landmark. The difference
between the EUD of spinal cord with PRV margin in 20-days treatment planand that in initial treatment plan was more than 1Gy but the difference in othertissues were less than 1Gy. Though our set-up accuracy was sufficient, EUD
of spinal cord with PRV margin was higher. It would appear that the higher
dose of spinal cord with PRV margin was derived from the change of patients’body contour from their weight loss.
Conclusions: Comparing with the report by Rotondo et al, The set-up accuracy in our institute was very sufficient. As a result of EUD, the patients
undergoing Head and Neck IMRT should maintain their weight during thecourse of therapy.
1235 poster
COMPARISON OF DAILY PROSTATE POSITIONS DURING CONFORMAL RADIATION TREATMENT OF PROSTATE CANCER USINGAN INTEGRATED CT-LINEAR ACCELERATOR SYSTEM
H. Aoyama1 2 , Y. Ootsuka1 , S. Inomata1 , M. Oita2 , Y. Azuma2 , K. Inamura1
1

O KAYAMA U NIVERSITY H OSPITAL, Central Division of Radiology, Okayama,Japan
2
O KAYAMA U NIVERSITY, Graduate School of Health Sciences, Okayama,Japan
Purpose: The purpose of this study is to quantify the magnitudes of thepositions of internal structures together with the correlation between the day-respectively for X, Y and Z axes in supine position and 3.4mm, 3.3mm and
2.8mm respectively in prone positionThe analysis of MVCT matching for first
10 fractions and last 15 fractions demonstrated that average value of shifts
and average SD were larger at the beginning of treatment in both subgroups.
For supine subgroup SD differences between both periods of irradiation werelarger and amounted 1.7mm, 2.7mm and 1.1mm respectively for X, Y and Z
axes, while for prone subgroup this differences were smaller and amounted
0.8mm, 1.9mm and 0.7mm respectively.
Conclusions: Both treatment positions are safe in term of 0.81.0cm margins for PTV.The repositions shifts are larger at the beginning of treatment
for both subgroups.Supine immobilization is associated with larger shifts infirst 10 fractions and smaller in last 15 fractions in comparison with prone immobilisation which is more constant in term of set up accuracy during wholetreatment.

Conclusions: Considerable differences between in-room CT images andDRR exist. These data demonstrate that there is a significantly greater shift
in the SI and AP directions than in the lateral direction for the entire patientgroup. We reject the hypothesis that prostate position and bony anatomy
agree perfectly. Applications such as our image guide system will, with routine clinical use, continue to improve the precision of external beam radiation
therapy for prostate cancer.
1236 poster
COMPARISON OF SET UP ACCURACY FOR PATIENTS IRRADIATED
TO PROSTATE CANCER IN SUPINE AND PRONE POSITION
D. Galas Swidurska1 , T. Bajon1 , T. Piotrowski2 , J. Kazmierska1
1
G REATER P OLAND C ANCER C ENTRE, 2nd Radiotherapy Department,
Poznan, Poland
2
G REATER P OLAND C ANCER C ENTRE, Physics Department, Poznan,
PolandPurpose: To compare set up accuracy during radiotherapy of prostate cancer
patients in supine and prone position using daily MVCT.
Materials: The study included 29 patients with prostate cancer irradiated using helical Tomotherapy technique between July 2009 and September 2010
in Greater Poland Cancer Centre. Each patient underwent planning procedure in both treatment positions supine with standard knee-fix stand (Sinmed Combifix SYS/2P) and prone with belly board (Sinmed Bellyboard BBCF/2P). Before CT scanning patients were asked to empty their bladder andthen to drink 500 ml of water. No special preparation of rectum like enema or
endorectal balloon were used. Patients were allocated into two subgroups on
the basis of dose volume histograms comparison for organ at risk 14 patientswere irradiated in supine position and 15 in prone position. Before each radiotherapy fraction patients were positioned according to skin markers. Daily
MVCT was performed for every patient. Obtained images were matched on
the basis of soft tissue structures with references slices from CT scanningfor radiotherapy planning. The shifts were compared for supine and prone
position subgroups. Furthermore the comparison between shifts for first 10
fractions and last 15 fractions was also performed for each subgroup.
Results: 682 MVCT matching were analysed , 327 for supine and 355 forprone position.The comparison of shifts between both subgroups showed that
average shifts were comparable and did not exceed 0.6mm. The average
standard deviation (SD) of this shifts amounted 3.7mm, 3.4mm and 2.7mm

Purpose: In order to safely administer high radiation doses to small lesions
as in radiosurgery, any geometric uncertainties in the treatment should be
minimized. In particular, correct patient positioning and stability during treatment are critical. We have initiated a systematic investigation, based on cone
beam CT (CBCT), of setup accuracy and intra-fraction motion for patients receiving radiotherapy to the entire brain. The aim of this study is to compare
two different types of patient immobilization, and to gather data from which todetermine the appropriate CTV to PTV margin for future radiosurgery treatments.
Materials: Thus far, 19 patients have been included in the study, all receiving whole brain radiotherapy in 4 fractions of 5 Gy. Two types of patient
immobilization were applied:- "conventional" fixation system: 15 patients "upgraded" fixation system: 4 patientsThe conventional system consisted ofa thermoplastic 3-points mask, combined with either a standard low-density
head support (8 patients) or an individually moulded head support (7 patients). The upgraded system consisted of a thermoplastic 3-points mask withdoubled edges for extra rigidity, and a low-density 3D shaped head support
with neck flaps. Both were obtained from Orfit Industries NV.Patient position
was verified using CBCTs (Varian On Board Imager). Two CBCT scans weremade at each treatment fraction: immediately before and after the treatment
delivery. The scans were matched offline to the planning CT, using the skullbone for reference. All shifts were recorded only for the purpose of this study,i.e. not for patient setup correction.
Results: The setup accuracy was estimated from the observed shift between the planning CT and the pre-treatment CBCT. The average of calculated setup errors for all fractions, expressed as a 3D vector, was 2.7 mm
for patients in conventional immobilization (58 fractions). For the upgraded
immobilization this was reduced to 1.6 mm (16 fractions). The amount of
intra-fraction motion was estimated from the observed shift between the pretreatment CBCT and the post-treatment CBCT. Considering X, Y, and Z directions separately, the shifts were either 0 or 1 mm in almost all cases (shift
values were rounded off to millimeters by the match software). When conventional immobilization was used, the percentage of 0 mm shifts was 63%.
When upgraded immobilization was used, this number increased to 75%.
From these results the average intra-fraction motion vector length was estimated as 0.95 or 0.81 mm, respectively, for the two fixation systems. Patient
rotations were analyzed separately from the translations, but the improvements, if any, were too small to be considered relevant.
Conclusions: The match results obtained from 74 treatment fractions thus
far demonstrate a benefit from a specialized fixation system for high dose /high precision treatments. When compared to a more conventional fixation
system, the combination of a 3D shaped head support and a reinforced fixation mask leads to an improvement in patient setup accuracy, as well as a
reduction in intra-fraction motion. Mainly based on these results we have established a CTV to PTV margin for SRS treatments of 2 mm, allowing for a
maximum setup error of 1 mm (due to table displacement after online matching), and an intra-fraction motion of 1 mm.
1238 poster
CTV2PTV MARGINS WHEN APPLYING A PRIORI SETUP CORRECTIONS FOR HEAD AND NECK CANCER TREATMENT
E. van Dieren1 , H. Richards2 , P. Helle2 , C. Ong2 , R. Sommer2 , S. Koch1
1
M EDISCH S PECTRUM T WENTE, Physics, Enschede, Netherlands
2
M EDISCH S PECTRUM T WENTE, Radiotherapy, Enschede, Netherlands
Purpose: With the advent of a priori kV imaging in radiotherapy, systematicand random errors in patient positioning are largely eliminated. Thus, margins
are defined only by intrafraction motion, possible deformations and matching

S 461

errors. The goal of this study is to establish the adequate margin based on
intrafraction motion of head and neck cancer patients, in combination with anassessment of the size of matching and deformation errors for these patients.
Finally, the effect of the new margin is shown on conformal plans.
Materials: For 30 patients with head & neck cancers, a priori setup correction
was performed using the Varian On Board Imager with orthogonal images
and DRRs showing the PTV(s) of the patients. When a deformation wasseen, the match was based on location of the PTV, with emphasis on thecenter of mass for elongated PTVs. After treatment, a posteriori EPIDs or kV
images were recorded and matched, to assess the intrafraction movement.
For patients with a "perfect" a priori match, the margin which ensures that thePTV covers 95% of all CTVs was calculated. Finally, for 10 patients, IMRT and
Rapid Arc plans were planned with the "standard" CTV2PTV margin (5mm)
and the online CTV2PTV margin. For imperfect matches, a variable margin
was used throughout the PTV.
Results: For small PTVs, the DRR - kV match was usually perfect, and apriori and a posteriori movement were limited to 3 mm for 95% of cases. For
larger PTVs, the deviation at the edges of the PTV ranged from 0 - 4 mm, but
intrafractional movement was very similar to that of small PTVs. Intrafraction
rotation and matching errors were negligible.For the perfect a priori matchgroup a CTV2PTV margin of 3 mm was planned. The DVHs for the plans were
improved with respect to plans with the standard margin of 5 mm, allowing adose reduction in the critical structures throughout the patients volume. For
larger PTVs, the variable margin concept was used, with a margin of 3 mm
in one area only and 5-7 mm in other regions. This usually allowed improved
sparing of one critical structure only (e.g. part of the the spinal cord adjacentto the PTV), still allowing substantial gains with respect to the plans with thestandard 5 mm margin.
Conclusions: This study shows a substantial advantage of the use of orthogonal kV images for a priori setup corrections for patients with head and neckcancer. Part of the a priori match error may be due to rotations, which are
not adequately seen in orthogonal images. CBCT may be the solution, but
only when "better" local match algorithms, in combination with non-rigid algorithms and on-the-fly replanning techniques are introduced clinically. This
may reduce the larger margins at distances from the center of mass of the
PTV, thus enabling sparing of more other critical structures (e.g. both thespinal cord and the parotids).Part of the a posteriori error may be attributed
to incorrect table positioning when applying a shift (the Varian table rounds to1 mm), making it likely that the large "intrafraction movement is 1 mm" groupis actually a "intrafraction movement is 0 mm" group. The magnitude of thistable effect warrants introduction of new table technology, such as seen in the
Varian TrueBeam Machine or in the Protura system.
1239 poster
DETERMINATION OF TOLERANCE TABLE FOR TREATMENT
COUCH POSITION USING AN IMAGE GUIDED SYSTEM
J. M. Perez Moreno1 , D. Zucca1 , P. Fernandez Leton1 , J. García RuizZorrilla1 , A. Minambres1
1
H OSPITAL S ANCHINARRO, Madrid, Spain
Purpose: The use of image-guided radiotherapy techniques (IGRT) aims to
reduce the uncertainties associated with patient positioning. One of the techniques more recent development is the cone beam CT (CBCT), consistingof the acquisition of volumetric images of the patient by a detector integrated
into the linear accelerator. Analyzing the results of all sessions of treatment toall patients in which positioning has been carried out with MV CBCT imaging,tolerances tables has been determined for the translational coordinates of thetreatment couch as function of pathology and immobilization system used.
Materials: In our institution we have MEDTEC immobilization systems.
These are carbon fiber immobilizers, designed to attenuate the radiation as
little as possible and allow the repositioning of patients in the treatment unit
in the same way as in the simulation of treatment. They also allow indexation on the couch treatment in fixed positions, so that can also be reproducible position of the treatment couch over all sessions.We use an offline
correction protocol for positioning systematic errors, based on acquiring a
CBCT before administration of the treatment session during the first five session. The positioning error is determined from the fusion of images of CBCT
to planning CT.Whenever a patient has been positioned system using IGRT
corrections and coucn positions have been recorded. Treatment location has
been recorded too.By analyzing all MVCBCT recorded, we determined foreach location the variation of treatment couch positions for each patient i σ ialong all sessions. σ i average for all patients whith similar treatment location, and therefore the same immobilizer, M (σ i) will estimate the variabilityof treatment couch position where a patient is accurately positioned using a
specific immobilizer. In this way we can establish a tolerance value basedon the immobilization system for vertical, lateral and longitudinal coordinatesof treatment couch and enable checking in the record and verification system. This tolerance value is determined as the product of M (σ i) by the factor
needed to cover 99% of cases for the statistic distribution.
Results: The following table summarizes the tolerances values found in thetranslational coordinates for different diseases, according to the immobilizerused:S 462

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

This values has been found analyzing 3647 cases, for as many treatment
sessions in which positioning has been carried out with cone beam IGRT
technique, distributed as follows: 726 abdomen, 724 chest, 1538 pelvic and659 head and neck.
Conclusions: The determination of tolerance tables for translational coordinates of the treatment couch and their checking by the record and verify
system involve an additional issue of safety for all patients, filtering possible
human error either in patient positioning or on displacements from the dropalignment to the treatment position.

always inside 2 mm before treatment. After treatment two additional images
were acquired. A total of 118 fractions (images before and after treatment)
were used to evaluate the intrafractional motion. Both marker match and bone
match were preformed on the pre and post treatment images to evaluate if
the intrafractional motion derived from the prostate or from patient motion.
ExacTrac Version 5.5 was used.
Results: For 65 of the 118 fractions there where intrafractional motion over
2 mm or 1.5 when matching on the implanted markers. When matching on
bony anatomy the intrafractional motion was larger than 2 mm or 1.5 for sixof these 118 fractions. See table 1 for additional results. Table 1: Results for
intrafractional motion.

Conclusions: On-linelocalization of surgical clips using ETX is technical feasible for IGRT in partial breast irradiation. CTV to PTV margins may be reduced from conventional 10 mm to 6 mm allowing more patients to be eligible
for PBI. Further reduction of margins would require a better characterizationof the target surrogate.

1240 poster
DOES
PLANNED-DOSE
TO
ORGANS-AT-RISK
REFLECTDELIVERED-DOSE IN HEAD & NECK INTENSITY MODULATEDRADIOTHERAPY?
J. Puxeu Vaqué1 , P. Correa2 , A. Shenoy3 , D. Husband3 , H. Mayles4
1

I NSITUT C ATALÀ D ’O NCOLOGIA (ICO), Department of Medical Physics andRadiation Safety, Barcelona, Spain
2
A RDEN C ANCER C ENTRE , U NIVERSITY H OSPITAL C OVENTRY, Departmentof Clinical Oncology, Coventry, United Kingdom
3
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Department of ClinicalOncology, Bebington, Merseyside, United Kingdom
4
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Bebington, Merseyside, United
Kingdom
Purpose: Intensity modulated radiotherapy (IMRT) offers us an opportunity
to limit dose to organs-at-risk. We undertook this study to determine whether
predicted dose to the spinal cord (SC) and parotid glands (PGs) reflected
the dose delivered calculated using on-treatment cone-beam computed tomographic scans (CBCT).
Materials: Five consecutive patients with nasopharyngeal cancer that received inverse-planned IMRT were selected. During planning it is our policy
to outline the spinal canal as surrogate for the SC. On treatment CBCT scans
were done weekly. To minimise inconsistency, a single oncologist (PC) reoutlined the SC and both PGs on the planning CT scan and on every CBCT
for each patient. The CBCT structure-sets were then exported to the original planning scan and the dose distributions recalculated. We analysed the
maximum dose given to the SC, the change in volume of and the mean dose
given to each PG.
Results: The maximum dose to the SC was averaged over the five patients.
The planned value was 45.5 Gy ± 7% and the estimated delivered value was
48.2 Gy ± 7%.At planning, the volume of the Ipsilateral (side with the higher
planned dose) PG (iPG) varied from 16.7 to 44cc and at the end of treatment
these values decreased to between 3.9 and 17.1 cc. The mean % decreasein volume was 55.4% (range 24-77%). Similarly at planning, the volume of
the contralateral PG (cPG) varied from 14.6 to 46.5 cc and this decreased
to between 5.8 and 20.6cc at the end of treatment. The mean % decreasein volume was 45% (range 17-69%).For the five patients the average of theplanned mean doses to each of the PGs was not significantly different fromthe dose received. For the iPG the average ratio of planned mean dose to
given mean dose was 1.03 (StdDev 5.6%) and for the cPG the average ratioof planned mean dose to given mean dose was 1.14 (StdDev = 21.8%).
Conclusions: The planning scans is a good predictor of the dose to thespinal canal. This is as expected since the CBCT’s are aligned to this scan using the spinal canal and the shell minimises movement of this organ. Parotid
glands both deform and reduce in volume. However, the mean dose to theparotids was not significantly different compared to that predicted.
1241 poster
EVALUATION OF INTRAFRACIONAL MOTION ON PROSTATEPATIENTS USING A 6D COUCH POSIONING SYSTEM
J. Bengtsson Scherman1 , A. Logadottir1 , P. M. Petersen1 , J. P. Bangsgaard1
1

T HE F INSEN C ENTER - R IGSHOSPITALET, Radiation Oncology, Copenhagen, Denmark
Purpose: To evaluate intrafractional motion, when using a 6D couch to position prostate patient based on matching of implanted markers. Evaluation
was also done to observe if the 6D positioning system introduces secondary
patient motion during treatment.
Materials: Ten prostate patients (age ranging from 58 to 76 years(averageof 67 years)), all receiving a dose of 78 Gy in 2 Gy fractions, were selected
to be positioned with the Novalis Tx System using the ExacTrac 6D Robotics
couch. The positioning was based on implanted gold markers. The positionof the patient should be inside a tolerance of 2 mm and 1.5 if possible andS 463

Conclusions: We have shown that the intrafractional motion for these patients derives from prostate motion and not patient motion. Currently there isno diet restriction for our patients; however this could be assessed in a further
study. Note on setup time: Introducing 6D positioning for prostate patients resulted in prolonged positioning time compared to the normal 3D positioning.
The reason for this is primarily because the radiotherapist had to enter thetreatment room for movement of the 6D couch whereas 3D positioning could
be preformed from the imaging console.

1244 poster
FIDUCIAL GOLD MARKERS IN INTENSITY-MODULATED RADIOTHERAPY FOR PROSTATE CANCER: APPLICATION OF THE NO
ACTION LEVEL PROTOCOL TO CORRECT PROSTATE MOTION
F. Garcia-Vicente1 , V. Fernández Bedoya1 , A. Gómez Barrado1 , A.
Zapatero2 , I. FERNÁNDEZ3 , M. MORA3 , C. Martin de Vidales2 , R.
BRIME3 , C. OLIVIER3 , L. Pérez1 , J. J. TORRES1
1
H OSPITAL U NIVERSITARIO L A P RINCESA, Department of Medical Physics,
Madrid, Spain
2
H OSPITAL U NIVERSITARIO L A P RINCESA, Department of Radiation
Oncology, Madrid, Spain
3
H OSPITAL U NIVERSITARIO L A P RINCESA, Urology, Madrid, Spain

1242 poster
EVALUATION OF RECTUM MOTION DURING PELVIC RADIATIONUSING CONE-BEAM COMPUTED TOMOGRAPHY (CBCT)
N. Tomic1 , A. Garant1 , I. Thibault1 , T. Niazi1 , D. Cuthbert1 , B. Bahoric1 , S.
Devic1 , F. DeBlois1 , T. Vuong1
1
J EWISH G ENERAL H OSPITAL, Radiation Oncology, Montreal, Canada
1243 poster
Purpose: Patients treated with external radiotherapy with prostate, rectum
and anal canal cancers experience day-to day changes in their rectal positionand volume. Image guidance at the time of therapy (IGRT) using kV CBCT,
which gives accurate 3D volumetric patient’s anatomy prior to every treatment can register those changes and it is suitable for adaptive corrections oftreatment positioning variations. The rapid fall-off in dose outside the target
in highly conformal radiotherapy techniques such as IMRT impose demand
for accurate target localization and tight PTV margins at the time of the treatment. This study assesses the magnitude of geometric center displacementsof upper, middle and lower third of the rectum during the course of IGRT
treatment employing CBCT.
Materials: Pelvic anatomy of 40 patients (26 rectum, 9 prostate and 5 anal
canal) was obtained using pre-treatment 3D imaging with Pelvis CBCT protocol on on-board imaging (OBI) system (v. 1.4 Varian Medical Systems, Palo
Alto). CBCT of prostate patients was performed on daily basis and twice aweek for anal canal and rectum cancer patients. The obtained reconstructed
CBCT images were co-registered with planning CT data using bony landmarks for rectal and anal canal cancer patients and prostate soft tissue visibility and prostate contours for prostate cancer patients. Contoured upper,
middle and lower third of the rectum on 3 CBCTs acquired during the courseof the treatment were compared with contoured parts of the rectum on CT
images. Daily geometric positions of the three volumes were compared togeometric centers on planning CT images, and the obtained relative mean
displacement of the center of the mass for all three thirds of the rectum wasanalyzed.
Results: Our preliminary results (Figure 1) suggest that the average movement in patient lateral direction for upper third of the rectum is 0.6±0.43 cm,
for middle third 0.46±0.39 cm and for lower third 0.38±0.34 cm. In verticaldirection we obtained for upper third of the rectum 0.48±0.32 cm, for middle
third 0.56±0.35 cm and for lower third 0.49±0.32 cm displacements. The
maximum displacement was observed for lower third of the rectum to be 1.93
cm in lateral and 1.37 cm in vertical direction.
Conclusions: For patients with rectum cancer the clinical target volume(CTV) includes rectum and mesorectum and planning target volume (PTV)
margin used for standard 3 fields 3D conformal radiotherapy is 1 cm which islarge enough to take into account the rectum motion and can give good coverage of the target. On the other hand, for anal canal cancers early studies
suggested that the use of IMRT technique is beneficial using very tight PTV
margin of 5 mm. However, our results suggest that this margin for lower thirdof the rectum should be enlarged to 1 cm in order to take into account the
motion of the rectum during the course of the treatment and cover the clinicaltarget volume.

FEASIBILITY STUDY FOR IMAGE-GUIDED PARTIAL BREAST
IRRADIATION USING EXACTRAC X-RAY
C. Garibaldi1 , F. Cattani1 , S. Comi1 , R. Luraschi1 , M. C. Leonardi2 , A.
Morra2 , G. Pedroli1 , R. Orecchia23
1
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Medical Physics,
Milan, Italy
2
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Radiation Oncology,
Milan, Italy
3
U NIVERSITÀ DEGLI S TUDI DI M ILANO, Milano, Italy
Purpose: To investigate the feasibility and reliability of an on-line image guidance procedure for external beam partial breast irradiation, based on stereoscopic X-ray imaging of surgical clips and to estimate the appropriate CTV to
PTV margin.
Materials: Under the hypothesis of a strong correlation between surgical clips
and tumour bed, excluding patients where breast was remodelled by plastic surgeon, surgical clips, placed at the periphery of the tumour bed during
lumpectomy can be used as radiographic markers visualized by ExacTrac Xray (ETX, BrainLAB, Germany). Ten patients have been enrolled in the study
so far. They received a dose of 12 Gy to the tumor bed with IORT followed
by a whole breast tangential fields irradiation with a dose of 37.05 Gy delivered in 13 fractions. The lumpectomy cavity was defined by 4-6 surgical clips
placed by the surgeon after IORT. All patients underwent a free breathing (FB)
and an end-expiration breath-hold (EEBH) CT scans with 3 mm thick slices
in order to evaluate the influence of respiration in the localization of the tumor
bed. All visible surgical clips were outlined in both CT scans to calculate theirmotion and to have a better visualization on the DRRs. Patients were positioned using lasers alignment to skin tattoos, two couples of X-ray images
were acquired in FB and EEBH and compared to the corresponding DRRs
using manual fusion to align the clips to evaluate localization error. Anothercouple of X-ray images was acquired in FB after correction to assess residual
error. Localization and residual errors were evaluated during the first 8 fractions. To estimate of the CTV to PTV margin we have considered breathing
motion and residual errors.
Results: The internal clip motion between FB and EE was, -1.7±1.1 mm,-1.5±1.2 mm, 0.9±0.8 mm in AP, SI and LR, respectively. For all patientsthe clips were clearly visible in one X-ray image while some difficulties were
found in the second image because some of the clips were hidden by bony
anatomy. In the table are shown the localization errors in FB and EEBH
and the residual error in FB along the three directions. No improvement inclip localization have been observed acquiring the X-ray images in EEBH
compared to FB. Estimating a breathing motion of about 3-4 mm, we havecalculated an isotropic CTV to PTV margin, including breathing and residual
errors, of 6 mm.

Purpose: To evaluate the efficacy of the No Action Level (NAL) protocol in
the reduction of systematic prostate displacements based on electronic portal
image (EPI) devices using intraprostatic implantation of fiducial gold markers.
Materials: Since August 2007, 172 prostate cancer (PC) patients scheduled for intensity-modulated radiotherapy (IMRT) at Hospital Universitario La
Princesa, have had gold markers implanted in the prostate. The protocol
has included, for localization purposes, the transrectal implantation of gold
markers (three pieces of 5x1.2mm, manufactured by Medizintechnik GmbH,Germany) in the prostate, placed through a pre-waxed 17G needle, two near
the base and one near the apex. The first 80 PC patients treated with theapplication of the NAL protocol, were included. For marker position measurements, we performed a digital match between the position of each marker in
the acquired EPI with the corresponding position in digitally reconstructed radiographs, 10 fractions per patient, on average. EPIs were obtained for three
beams: left and right postero-lateral oblique, as well as, postero-anterior tomeasure the positions of each marker. Displacements of the prostate centerof mass were calculated by in-house software. Based on this, the necessary
margins for the correct treatment of the prostate were calculated.
Results: Two thousand and four hundred marker positions were available forthe analysis. The mean position of the prostate mass center showed deviations lower than 0.5 mm. The standard deviations of the total systematiccomponent (preparation and setup) were 0.8, 1.7 and 1.1 mm in the left-right,
anterior-posterior and craneo-caudal directions respectively, using the NAL
protocol, versus 2.7, 3.4 and 4.1 mm without the NAL protocol. The standard
deviations of the random component (inter-fraction fluctuation) were 1.4, 2.6
and 1.7 mm, respectively. The corresponding calculated margins, according
to the Van Herk formula, would be: 3, 6 and 4 mm on the left-right, anteriorposterior and craneo-caudal directions, respectively. We also observed an
asymptotic trend in the reduction of the total systematic component, as we
became more experienced with the procedure.
Conclusions: The NAL protocol has lowered by half the systematic component of the position errors allowing the planning margin reduction. A decreasein the morbidity derived from PC radiation therapy could be expected1245 poster
FINE VS COARSE MVCT: EVALUATION OF INTER-FRACTIONERRORS IN PATIENTS TREATED WITH TOMOTHERAPY®
P. Antognoni1 , P. Barbieri1 , A. Bruni1 , E. Cenacchi2 , P. Ceroni2 , G. Guidi2 ,B. Lanfranchi1 , E. Mazzeo1 , B. Meduri1 , M. Parmiggiani1 , S. Pratissoli1 , G.
Tolento1 , E. Turco1 , T. Costi2 , F. Bertoni1
1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Radiation Therapy,
Modena, Italy
2
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Physics , Modena, Italy
Purpose: Helical Tomotherapy is capable to perform megavoltage computed
tomography (MVCT) imaging before treatment with different scan length andslice thickness (fine, normal and coarse). Total scan time and dose depend

S 464

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

on the slice thickness. This study aims to investigate differences in terms ofinter-fraction error detection between fine and coarse MVCT modalities
Materials: MVCT was used to verify patient position and tumor target localization before each treatment. RTT randomly used fine (2 mm slice thickness) or coarse (6 mm slice thickness) modalities. MVCT total scan time
was calculated.Three-dimensional translational (lateral, longitudinal, and vertical) and rotational corrections were calculated using the TomoTherapy software. The operator didn’t know which kind of modality was being used andperformed manual adjustment if the automatic image fusion did not match
the KVCT data. The inter-fractional setup variations evaluated with fine andcoarse MVCT were recorded and corrected before treatment. The comparisons between fine and coarse measures were analyzed using Student’s ttest
Results: From January 2010 to May 2010 data obtained from 38 patients(pts) with tumors in 5 different sites (4 brain, 12 head & neck, 11 lung, 7 abdominal, 4 prostate) were analyzed.We evaluated 219 fine MVCT and 219
coarse MVCT: the mean lateral inter-fractional setup error was -0.74 mm and
0.6 mm, respectively (p=0.3). The mean longitudinal inter-fractional setup
was -2.4 mm (fine) and -2.17 mm (coarse), p=0.3. The mean vertical interfractional setup was +3.9 mm (fine) and +3.6 mm (coarse), p=0.08. The
mean 3D displacement (3Dd) in lateral, longitudinal, and vertical directions
for the 5 sites was 6.16 mm (fine) and 6.1 (coarse), p=0.7. We also evaluated data for each site separately. For brain 3Dd was 5.14 mm (fine) and5.35 mm (coarse), p=0.61; for Head & Neck 3Dd was 4.17 mm (fine) and3.8 mm (coarse, p=0.18; for lung 3Dd was 8 mm (fine) and 8.2 mm (coarse),
p=0.76; for abdomen 3Dd was 6.98 mm (fine) and 7.25 mm (coarse), p=0.6;
for prostate 3Dd was 7.87 mm (fine) and 7.1 mm (coarse), p=0.14.Mean time
for coarse and fine MVCT scan was 202 seconds and 542 seconds respectively.

setup and at treatment console for monitoring during treatment. The treatment planning CT is used to provide real-time reference surface image. Prior
to use, the external patient contour is extracted from the CT and sampled toprovide sufficient resolution but reduced data points so that real time images
can be created depending on the actual beam geometry. The surface image is aligned to the isocenter and then updated to correspond to the current
gantry, collimator, and couch shift using transformation matrices. Corrections
can be performed for divergence at large off axis distances. Imaging software
will then overlay the reference image or user selected contours on the video
image.

for the Z axis. Placing the micro-multileaf on the head of the linac we haveobtained images of sufficient quality to compare with the planning, although
it is inevitable that if they are used, bony structures are necessarily present
within the exploration area. The quality and accuracy decrease significantly
when the MVCB is performed with table turn due to physical limitations on the
MVCB arc length.

IMPLEMENTATION OF AN ELECTROMAGNETIC TRACKINGSYSTEM FOR PATIENTS RECEIVING RADIOTHERAPY TO THE
PROSTATE
H. McNair1 , A. Kavanagh2 , E. Alexander3 , S. Eagle4 , W. Ingram5 , C.
South5 , P. Evans2 , D. Dearnaley1
1
T HE I NSTITUTE OF C ANCER R ESEARCH AND T HE R OYAL M ARSDEN NHSF OUNDATION T RUST, Sutton, United Kingdom
2
I NSTITUTE OF C ANCER R ESEARCH, Joint Department of Physics, Sutton,
United Kingdom
3
I NSTITUTE OF C ANCER R ESEARCH, Sutton, United Kingdom
4
R OYAL M ARSDEN N HS F OUNDATION T RUST, Radiotherapy Department,
Sutton, United Kingdom
5
R OYAL M ARSDEN N HS F OUNDATION T RUST, Radiotherapy Physics, Sutton,
United Kingdom

1247 poster

1246 poster
HARDWARE AND SOFTWARE REQUIREMENTS FOR BEAMS EYE
VIEW VIDEO IMAGE GUIDED RADIATION THERAPY
J. Barbiere1
1
H ACKENSACK U NIVERSITY M EDICAL C ENTER, Radiotherapy Oncology,
Hackensack, USA
Purpose: There currently are no commercial systems that provide a real time
Beams Eye View (BEV) video image of the patient in the treatment position.
This work presents hardware and software requirements for BEV video Image Guided Radiation Therapy (IGRT). When implemented, the system will
provide guidance on daily patient positioning and also continuous monitoring
during treatment.
Materials: The hardware consists of a wireless video camera mounted to theside of the linac head such as to provide a BEV image at the same Source
Axis Distance (SAD) as the therapy beam and radiation field light indicator.
Since the camera is mounted outside the radiation field it can be shielded
to minimize radiation damage. The image at the radiation axis is recorded
through a set of reflective mirrors and directed congruent to the radiation fieldby thin two-way mylar mirror on the axis placed in the tray slot. The mylar
will have no noticeable effect on the clinical photon radiation or light fields.
The wireless camera is free to move with the linac and transmits a signal to areceiver in room. The receiver is connected to computers in room for patient

PRV1 and PRV2 was used to adjust the standard imaging protocol during
treatment.
Results: We noticed small difference in spinal cord delineation (mean K index= 0.8, min K= 0.703 max K = 0.83). The maximum deviation rate observed
was 1.8 mm. However, the error rate in image matching was around 1 mm.
Together the PRV1 margin was defined as 3 mm (in A-P, L-R and S-I direction). The safety margin PRV2 was estimated as 5 mm margin (in A-P, L-R
and S-I direction) to take account uncertainties in SC delineation and effectsof blurring caused by daily treatment execution errors.
Conclusions: The effect of delineation uncertainties for organ at risk should
not be underestimated, being the main cause of systematic errors. The concept of two PRV around the SC is a simple way of to adapt for each patient
imaging protocol depending on treatment planning Imaging during treatment
can be used more efficient and only when needed by the use of two PRV
concept which can reduce linac workload even in high precision high dosetreatment planning.
1249 poster

Results: The process was simulated using MATLAB with the imaging toolbox
for a standard tangential breast case. Obviously, the system is limited topatient areas that are not covered with immobilization devices. Unassisted
video setup images indicated significant variations in both the patient head
and arm position when compared to the planning CT.
Conclusions: The hardware and software specifications indicated in thiswork can serve as the basis for construction of a real time beams eye view
video imager useful for daily patient setup and continuous monitoring during
treatment.

Conclusions: These results, even though they cannot be conclusive because of the small number of evaluations performed, show that there are
no statistically significant differences in terms of inter-fractional setup errors
detection between fine and coarse MVCT. These findings might justify theuse of coarse MVCT to avoid time-consuming procedures in several cases
except for small targets or targets very close to sensitive structures

S 465

IGRT IN RADIOSURGERY WITH LINAC: MVCBCT (MV-VISION)WITH BRAINLAB M3 MICRO-MULTILEAF COLLIMATOR STUDY IN
PHANTOM OF THE ACCURACY INTRINSIC AND APPLICABILITYSYSTEM
V. Crispin1 , V. Gonzalez Perez1 , J. Gimeno2
1

I NSTITUTO VALENCIANO O NCOLOGIA, Department of Medical Physics andRadiation Safety, Valencia, Spain
2
FIVO, F UNDACIÓN I NSTITUTO VALENCIANO DE O NCOLOGÍA, Departmentof Medical Physics and Radiation Safety, Valencia, Spain
Purpose: The ability to set the isocenter of a linear electron accelerator ina three-dimensional image taken with the patient’s own treatment beam isan essential fact. Before using clinically MV-CBCT technology in conjunction
with a micro-multileaf colimator (m3) we need to determine the degree of
accuracy of the system and its applicability in arches with angle of rotation of
the table equal to 0 as well as other angles. The aim of this study is to get toknow both of them.
Materials: The MV-CBCT system used is called Mvisionthe manufacturer
Siemens Oncology Care Systems, Concord CA, in research mode, whichuses the treatment beam itself and the EPID Oncor Impression Linear Accelerator Plus Expression Avangard. The micro-multileaves collimator used
was Brainlab M3. To determine the intrinsic accuracy of the system, a process whose only uncertainty is due solely to the system under study must be
designed, eliminating any uncertainty outside the system. We used a Rando
type anthropomorphic phantom and a stereotactic space. For volumetric image management, we had research software given by Oncology Care Systems, Concord CA.
Results: For angles of rotation of the table equal to 0 and without placing
the micro-multileaf the difference between the stereotactic coordinates obtained from conventional CT and-CT MVCB were: for the X axis, an average
difference of 0.1 mm; for the Y axis, 0.2 mm; and for the Z axis, -0.1 mm;with standard deviations of 0.3 mm for the X axis, 0.3 mm for the Y axis,
and 0.4 mm for the Z axis. It was also found that the maximum differences
along the axes were 0.6 mm for the X axis, 0.6 mm for the Y axis, 0.8 mm

Conclusions: The results obtained with the table set at 0◦ and without M3
allows us to conclude that the MV-CBCT under the conditions in which the
TC scan was performed (similar slice thickness and pixels size) shows nosignificant differences with the TC regarding accuracy and geometrical reproducibility; the accuracy is much better than a millimeter, being of the orderof a tenth of a millimeter, being therefore appropriate for its use in stereotactic radiosurgery. The MVCBCT + M3 provide a tool based on the linear
accelerator that makes a view of the patient possible. However its accuracy
is significantly reduced when performed with table turns.
1248 poster
IMAGE GUIDED FORMULA BASED ON SET UP ERRORS VARIATION
AND STEEP DOSE GRADIENTS FOR TREATMENT OF HEAD AND
NECK AND LUNG CANCER
C. Leleu1 , E. Moser1 , S. Danhier1
1
C ENTRE H OSPITALIER I NTERCOMMUNAL DE C ORNOUAILLE, Quimper,
FrancePurpose: Treatment plans containing dose escalation and steep dose gradients between target volume and spinal cord (SC) require high precision
treatment planning. No action level imaging strategy minimizes systematicdeviation, while daily online adaptation of the treatment is not widely available at present. By defining planning organ at risk volume (PRV) margins,dose risk estimation can be assessed in both conformal (3DCRT) or intensity
modulated (IMRT) radiotherapy. After evaluation of SC delineation, geometric uncertainties in both control CT scans and portal imaging, we defined two
PRV values for the SC dose estimations to standardize our image guided
protocol during treatment
Materials: Estimations of systematic and random deviations were evaluatedin 66 patients (33 H$N and 33 Lung) by the used of both treatment planningand control scanning plus portal imaging (520 EPID). Inter-observer variability
in SC delineation was evaluated using maximum distance deviation, conformity index and kappa functions. A first PRV was calculated around the SC
by taking account this inter-observer variation and observed matching uncertainties. A second PRV was calculated to represent the dose per fraction to
SC with a 90% confidence level. The difference in maximum dose among

Purpose: The Calypso®4D localisation system has been developed to localise the target prior to, and track during, treatment delivery using implanted
electromagnetic markers. Initial experiences of Calypso®in patients receiving
radiotherapy for prostate cancer are reported.
Materials: The Calypso®4D localisation was installed at the Royal Marsden
NHS Foundation Trust in Jan 2010. Patients referred for radical radiotherapy to the prostate had three Calypso markers (8mm x 1mm) implanted in
the apex, right base and left base of the prostate. A planning CT scan was
acquired with 1.25mm slice thickness for localisation of markers then reconstructed at 2.5mm for treatment planning. A 3D conformal plan produced using margins defined in the CHHiP protocol. The coordinates of the isocentre
and the centres of the marker were assessed from the CT scan and enteredinto the Calypso system. At treatment the electromagnetic array is placed
above the patient and the system determines the location of each marker
and so allows the target to be positioned relative to the isocentre. Trackingof the target during treatment is possible if the array can be positioned within~17cm of the markers.
Results: Nineteen patients have had markers implanted in the prostate withno adverse effects. Fourteen patients have commenced treatment and Calypso has been used to localise the prostate prior to treatment in thirteen
patients. The tracking function was able to be performed in ten out of the thirteen patients. Intrafraction motion observed was the greatest in the superiorinferior and anterior- posterior directions.
Conclusions: Implementation of the Calypso system was successful. A
comparison of CBCT and Calypso is in progress to confirm the accuracy of
Calypso in determining prostate position prior to radiotherapy
1250 poster
INCREASED PATIENT THROUGHPUT FOR TREATMENT WITH
HELICAL TOMOTHERAPY
K. Petersson1 , M. Enmark2 , C. Ceberg1 , T. Knöös21
1
L UND U NIVERSITY, Medical Radiation Physics, Lund, Sweden
2
S KÅNE U NIVERSITY H OSPITAL, Radiation Physics, Lund, Sweden
Purpose: Treatment with helical tomotherapy is beneficial for many patientscompared to treatment with a conventional C-arm linac. To be able to treat
more patients with tomotherapy the total time in the treatment room per fraction for every patient has to be shortened. One way of doing this is to replace
the time consuming use of MVCT imaging for positioning with a fast laser
scanning positioning system for most of the fractions in a treatment. A time
study has been performed to quantify the potential time save per fraction andsubsequently the possible increased patient throughput.
Materials: The sentinel system (C-Rad AB) was the laser scanning systemused for the positioning of the patients when the MVCT imaging system was
not utilized. The study was performed for 15 patients (2-5 fractions). In the
study; the time when the patient entered the treatment room was registeredas well as the time when the patient left. The time it took to MVCT scan thepatient and the time it took to match the MVCT scan to the planning kVCTS 466

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

scan was registered. The total treatment time (patient entering treatment
room until patient leaving) for fractions when the laser scanning system wasused was compared to fractions when the MVCT imaging system was used.
The increased patient throughput was calculated based on an imaging protocol that stipulates that the MVCT imaging system is used for positioning of
the patients the first three fractions and then once a week, instead of the normal everyday use. This was applied for a standard curative treatment of 30
fractions (6 weeks), resulting in MVCT imaging for only 8 of the 30 fractions.
For the remaining fractions the laser scanning system was used.
Results: The positioning of the patient with the use of MVCT imaging (scan+ match) took in average 15 minutes to perform. The total treatment time wasin average 39 minutes when the MVCT system was utilized and 20 minutesin average when the laser scanning system was used. A box plot of the totaltreatment times can be seen in Figure 1. Reduced MVCT imaging according
to the proposed protocol will result in an increased patient throughput of about
40%.

implantation CT series to evaluate the impact of rectal separation on rectal
dose distribution. To create a digitized rectal volume independent view inrectal dose changes, absolute dose related ccm values were also compared.
Results: The procedure was well tolerated with 10 patients reporting transient local discomfort at the implantation site. Inserting the balloon in
the prostate rectal interspace resulted in median measurements as follows:
anterior-posterior separation of 19.15 mm (ranged 14.6 - 23.4) and a widthof 30.45 mm (ranged 21.1 - 36.6). The cranio-caudal span of the balloon
is fixed and measure 45mm. These separations resulted in an average reduction values (± standard deviation) of the rectal V50: 48.4% (±19.7%),
V70: 74.5% (±17%), D70: 50.8% (±19.9%), D80: 60.3% (±19.7%), D90:
68.7% (±18.3%), and D100: 81.2% (±24.3%) as well rectal D2cc: 15.8%(±11.5%), and D0.1cc: 3.9% (±6.4%).
For all patients, there was minimal or no discomfort at the perineum. One
patient had proctitis Grade 1. None had proctitis above Grade 1.
Weekly follow up demonstrated stable separation and no change in balloon
position and shape during the XRT in 19 cases. In three cases, the balloon
deflated prematurely due to contact with fiducial markers introduced transrectally (perpendicular to the balloon) subsequent to balloon placement. No
premature deflation happened in cases where the fiducial were implanted
transperinealy. The balloons could not be demonstrated in 6 months images
as expected.
Conclusions: Insertion of the biodegradable balloon in to the prostaterectum interspace is safe with no unexpected procedure related side effects
or complications. The device insertion resulted in a stable separation of theprostate from the anterior rectal wall and a dramatic volume reduction of therectum exposed to high radiation dose.

Conclusions: This study shows that a substantial time save is possible whenan alternative method to MVCT imaging is used for positioning of the patientwhen treated with helical tomotherapy. The time saved can be used for aconsiderable increase in the number of patients treated with this technique.
There is also another benefit with the reduction of MVCT scan for the patients
namely the reduction in received dose from MVCT scans.
1251 poster
INTERSTITIAL BIODEGRADABLE BALLOON FOR RECTAL DOSE
REDUCTION: DOSIMETRIC RESULTS OF A MULTI-CENTER STUDY
C. Melchert1 , E. Gez2 , M. Garg3 , G. Bohlen1 , S. Kalnicki3 , G. Scarzello4 , I.
Koziol5 , M. Anscher6 , S. Cytron7 , A. Paz7 , T. Torre5 , M. Bassignani5 , F. Dal
Moro4 , D. Jocham1 , R. Ben Yosef2 , G. Kovács1
1
U NIVERSITÄT L ÜBECK, Departments of Urology and Interdisciplinary
Brachytherapy, Lübeck, Germany
2
T HE T EL -AVIV S ORASKY M EDICAL C ENTER, Department of Radiation
Oncology, Tel Aviv, Israel
3
M ONTEFIORE M EDICAL C TR, Department of Radiation Oncology, Bronx,
USA
4
U NIVERSITY, Padova, Italy
5
V IRGINIA C OMMONWEALTH U NIVERSITY, Department of Urology, Richmond, VA, USA
6
V IRGINIA C OMMONWEALTH U NIVERSITY, Richmond, VA, USA
7
B ARZILAI M EDICAL C ENTRE, Ashkelon, Israel
Purpose: Disclosure: Adrian Paz MD is co-founder of the ProSpace balloon
manufacturer, BioProtect. Rami Ben Yosef MD is BioProtect advisory board
memberGyrgy Kov MD PhD is BioProtect advisory board memberTo evaluate
dose reduction achieved by the implantation of an interstitial inflatable andbiodegradable balloon device aiming to lower rectal doses with virtual 3D
conformal external beam radiation treatment.
Materials: Twenty-two patients with localized prostate cancer who elected
to be treated with XRT (3D CRT or IMRT) were accrued to a multi-centerprospective study to undergo interstitial and transrectal ultrasound guided
placement of the inflatable balloon device in to rectal-prostate interspace prior
to initiation of treatment. Baseline CT (MRI in 2 cases) scans were comparedto post-balloon placement scans. Additional weekly imaging (CT, ConeBeam
or US) scans were performed during XRT and at 3 and 6 months after balloon
implantation to ensure stability and self-degradation of the balloon. For the
purposes of this report, all CT data were collected for reevaluation by central evaluators. Therefore, 3D conformal virtual planning was performed by
one physicist after contouring by one radiation oncologist to minimize interobserver variations. Treatment planning was performed on pre and post balloon

1252 poster
INVESTIGATION OF CORRELATIONS BETWEEN PATIENT POSITIONING CORRECTIONS FROM CONE BEAM CT DATA AND LASERSCANNED BODY SURFACE DATA
K. Wikström1 2 , K. Nilsson2 , U. Isacsson1 2 , A. Ahnesjö2
1
D EPARTMENT OF M EDICAL P HYSICS U PPSALA U NIVERSITY H OSPITAL,
Medical Physics, Uppsala, Sweden
2
U PPSALA U NIVERSITY H OSPITAL A KADEMISKA S JUKHUSET, Oncology,
Radiology and Clinical Immunology, Uppsala, Sweden
Purpose: A gantry mounted 3D cone beam CT (CBCT) system can give accurate patient positioning corrections, although the time resolution is limitedby the maximum gantry speed of one revolution per minute. CBCT also gives
some additional dose to the patient. A faster and dose-less technique is optical imaging of the body surface given that the position of the target volume
can be correlated with the patient outline. The aim of this study is to investigate the correlation between positional corrections determined with a CBCT
system (Elekta Synergy, XVI) and a 3D body surface laser scanning system(BSLS) (Sentinel, C-rad, Sweden).
Materials: The corrections for nine patients (54 fractions) in the pelvic region
and nine H&N-patients (71 fractions) were investigated retrospectively. BSLS
scans were performed for every fraction and CBCT images were acquired forthe first three fractions, and then for every fifths fraction. The CBCT images
were registered to the planning CT study used as the reference by an automatic rigid registration method including rotations. The BSLS surfaces wererigidly registered to the external of the reference CT image by a modified iterative closest point algorithm also including rotations. Similar registrations
were also done to a BSLS reference captured during one of the first treatment fractions. The set up corrections determined from these independent
registrations were then analyzed.

Results: For patients treated in the pelvic region 24%, 53% and 84% of theregistrations agreed within 3, 5 and 8 mm respectively between the CBCT and
BSLS system. For the H&N patients 20%, 61% and 92% of the registrations
agreed within 3, 5 and 8 mm, respectively. The corresponding results whenthe BSLS reference was used were 44%, 75% and 96% for the pelvic regionand 55%, 83% and 96% for H&N patients.
Conclusions: The correlation of the BSLS and the CBCT data was highest
when a BSLS reference was used. The fact that the H&N fixation is notincluded in the external of the CT reference but is detected by the BSLS
system reduces the correlation for H&N patients in this study. Patients treatedin the pelvic region might lose or gain weight between CT and treatment andthis affects BSL registration more than the CBCT registration. Our results
suggest that BSLS corrections should be implemented with a BSLS reference
to achieve the highest correlation to corrections done with a CBCT system.
1253 poster
LOCALIZATION AND REAL-TIME FIDUCIAL TRACKING OF THE
PROSTATE WITH A RADIOACTIVE MARKER
W. de Kruijf1 , J. Verstraete2 , L. Van den Bergh2 , S. Hol1 , R. Davits3 , B.
Wijsman3 , B. Corn4 , K. Haustermans2 , P. Poortmans1
D R . B ERNARD V ERBEETEN I NSTITUUT, Tilburg, Netherlands
2
U NIVERSITY H OSPITAL G ASTHUISBERG, Leuven, Belgium
3
T WEE S TEDEN H OSPITAL, Tilburg, Netherlands
4
T EL AVIV M EDICAL C ENTER, Tel Aviv, Israel
1

Purpose: To evaluate the localization accuracy of an investigational gantrymounted tracking system (RealEye, Navotek Medical Ltd., Israel) and toevaluate the implantation feasibility and stability of the implanted low-activity
iridium-192 source in the prostate (Tracer, Navotek Medical Ltd). RealEye
tracks in real time the location of the Tracer for the purpose of patient positioning guidance as well as target-position monitoring during treatment.
Materials: This multi-institutional (2) EC-approved study includes a total of 20
patients implanted with the Tracer alongside standard gold seeds. Eligibility
criteria include non-metastasised adenocarcinoma of the prostate; age ≥ 45
years; estimated prostate volume ≥ 30 ml; scheduled external radiotherapy
with curative intent; positioning verification according to the local protocol;
no limitations for pelvic imaging (such as hip prosthesis); informed consent.
Implantation feasibility is scored by the urologist and by the position of themarker in the prostate. Two follow-up CT-scans are made during the treatment period to evaluate Tracer stability. The changes in intermarker distances(IMD) over time between the Tracer and each of the gold seeds are comparedto the changes in IMD between the gold seeds themselves to assess the stability of the Tracer within the tissue, relative to that of the gold seeds. During delivery of radiotherapy, positioning verification is done with the standard
on-line verification procedure based on the implanted gold seeds, using MVand/or kV-images. At 5 treatment sessions, cone beam CT (CBCT) is madebefore and after delivery of radiotherapy, and measurements made by the
RealEye system are recorded before and after each CBCT. The absolute location of the Tracer as measured from the CBCT images and by the RealEyesystem are compared (total of 4 comparisons per session).
Results: In all 20 patients the tracer was successfully implanted in theprostate. The mean change in IMD involving the gold seeds alone is 1.4
mm and the mean change in IMD between the Tracer and the gold seeds is
1.2 mm. Of the CBCT images, 3 could not be used because of smearing of
the fiducials due to prostate and/or patient movement. The mean 3D vector
length difference between CBCT and RealEye localization for the remaining
384 comparisons is 1.3 mm. The mean 3D vector length between the RealEye measurement before and after CBCT, which is a measure of prostate
movement during the measurements, is 1.1 mm.
Conclusions: Tracer implantation in the prostate is feasible. The stability ofthe tracer is at least as good as the stability of the gold markers. The RealEye tracking system can continuously and in real time localize an implanted
radioactive fiducial marker with sufficient accuracy for use in patient positioning and target position monitoring during external beam radiation therapy ofthe prostate.
1254 poster
MVCT IMAGE GUIDANCE IN HELICAL TOMOTHERAPY FORPATIENTS WITH VERTEBRAL TUMORS: IMAGE RESOLUTION AND
INTEROBSERVER VARIABILITY
S. Levegrun1 , C. Pöttgen1 , J. Abu Jawad1 , K. Berkovic1 , R. Hepp1 , M.
Stuschke1
1
U NIVERSITÄTSKLINIKUM E SSEN, Department of Radiotherapy, Essen,
Germany
Purpose: High precision radiotherapy of vertebral tumors, either for reirradiation of vertebral metastases or as high dose radiotherapy of vertebral sarcomas, requires high accuracy image guidance to correctly position the required
steep dose gradients. We assessed the image resolution of megavoltage(MV) CT scans in helical tomotherapy and evaluated the achievable precisionof image guidance for patients with vertebral tumors.

S 467

Materials: To investigate MVCT image resolution, a dedicated phantom wasconstructed consisting of a set of 8 plastic plates (thickness 2 mm, density
1.4 g/cm3 ) arranged in parallel with different spacing between 2 and 14 mm,increasing in steps of 2 mm, embedded in a water tank. To assess the transverse (longitudinal) MVCT image resolution, the phantom was placed on the
couch with plates oriented parallel to the sagittal (transverse) plane for imaging. MVCT scans were recorded with predefined pitch values "fine", "normal", and coarse", corresponding to a slice thickness of 2, 4 and 6 mm, respectively. Phantom measurements were repeated using titanium instead ofplastic plates to resemble the metal implants in many patients with vertebral
tumors. To assess the precision of MVCT image guidance, we determined theinterobserver variability of the correction vectors of the set-up errors obtained
independently by 5 experienced radiation oncologists from MVCT scans of
5-15 fractions per patient. Overall, data from 4 patients, 2 with titanium implants and 2 without, were reviewed, resulting in 205 correction vectors from
41 fractions.
Results: In transverse MVCT images, all plates of the resolution phantom
can be resolved. Using "fine" pitch, the smallest distance between 2 plates
that can be resolved in sagittal and coronal images is 6 mm. The imageof a single plate extends longitudinally over 4 slices. Using larger pitch values, longitudinal image resolution is further degraded. A distance of 6 mm
between 2 titanium plates is the smallest resolvable value ("fine" pitch), indicating that the insertion of metal instead of plastic did not further deteriorate
the longitudinal resolution. The interobserver study revealed that the variances around the mean set-up error, determined per patient and per fraction
by the 5 observers, are largest in longitudinal direction followed by the vertical and lateral directions with standard deviations of 1.45, 1.16, and 0.88mm, respectively. The variance in longitudinal direction is significantly larger
than in vertical direction (p=0.0005). The latter is significantly larger than inlateral direction (p=0.0001). This may reflect the poorer longitudinal MVCT
resolution compared to the transverse resolution.
Conclusions: Tomotherapy MVCT settings represent a compromise between longitudinal image resolution and imaging speed. For certain clinicalapplications such as vertebral tumors, however, a better longitudinal resolution is desirable.
1255 poster
PATIENT MONITORING DURING TREATMENT USING SENTINELLASER SCANNING SYSTEM
C. Thornberg1 , M. Krantz1 , F. Nordström1 , R. Ljungqvist1 , S. Bäck1
1
S KÅNE U NIVERSITY H OSPITAL , M ALMÖ, Department of Radiation Physics,
Malmö, Sweden

Purpose: During treatment delivery, it is crucial that the patient maintain thesame position, ensuring that the treatment is delivered in accordance with thetreatment plan. A laser scanning system (C-RAD SentinelTM ) was clinicallyinstalled in 2009 for evaluation and development of patient monitoring andgating functionalities. The purpose of this ongoing work was to investigate
patients movements during treatment and identify differences among patientgroups.
Materials: The Sentinel system consists of a scanner unit containing thelaser and a camera, acquiring a 3D surface image of the treatment area by
sweeping a laser line along the patient. The maximum deviation from an estimated baseline of normal breathing movement during treatment was analysed for two patient groups; prostate cancer and breast cancer treatments.
The normal breathing pattern was corrected for in the system. A comparison with positioning errors of the patients according to the image verification
system was performed in order to see if patients with large positioning errors
also showed larger deviations during the monitoring. Time aspects of patient
movements during treatment were also investigated.
Results: The average maximum deviation from the normal breathing patternwhen monitoring patient movements during treatment was 6.8 ±4.1 mm and
5.4 ±2.1 mm for prostate and breast treatments, respectively. Generally,
patients with a higher maximum deviation also generally showed a higher
mean deviation from the normal breathing movement. The standard deviationof the maximum value, in terms of the movement between different fractions
for the same patient, tends to be higher for prostate patients (ranging between
0.7-5.0 mm) than for breast patients (ranging between 0.6-2.9 mm). There isa clear tendency that patients movements increase after 1.5 2 minutes. Also,
the patient with the highest maximum deviation received an IMRT treatment,
which might be due to a longer treatment time than a conventional treatment.
Conclusions: The differences in movement between patients with breast
treatment and prostate treatment was demonstrated, with prostate patients
generally showing more movement as well as a wider range between different
fractions. The results could be useful in the clinic concerning frequency ofimaging, time aspects and workflow. The scanning system could also be avaluable tool for the treatment personnel on individual patient basis.

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IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

IGRT: T REATMENT DELIVERY AND PATIENT POSITIONING

1256 poster

1257 poster

PROSTATE IMAGE GUIDED RADIOTHERAPY USING QUANTITATIVE 3D ULTRASOUND IMAGING: INTER- AND INTRA-OPERATORASPECTS.
S. van der Meer1 , E. Bloemen- van Gurp1 , J. Hermans1 , D. Heuvelmans1 ,R. Voncken1 , C. Grubbels1 , M. Berbée1 , E. Seravalli1 , P. Visser1 , L.
Lutgens1 , F. van Gils1 , F. Verhaegen1
1
MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS TRICHT, Department of Radiation Oncology, Maastricht, Netherlands

RESIDUAL ERRORS IMMEDIATELY AFTER ON-LINE CORRECTION:PROSTATE OR PATIENT MOVEMENT?
U. Schick1 , N. Rosenfelder1 , C. Lamb2 , K. Thomas3 , A. Aitken4 , N. vanAs1 , V. Khoo1
1
R OYAL M ARSDEN H OSPITAL, Clinical Oncology, London, United Kingdom
2
R OYAL M ARSDEN H OSPITAL, Radiation Physics, London, United Kingdom
3
R OYAL M ARSDEN H OSPITAL, Statistics Department, London, United
Kingdom
4
R OYAL M ARSDEN H OSPITAL, Radiation Therapy, London, United Kingdom

Purpose: To allow for high dose, high precision radiation imaging prior to aradiation session is performed in Image Guided Radiotherapy (IGRT). Conebeam imaging can visualise bony anatomy and fiducial markers. However, forprostate cancer, visualising the prostate itself is more desirable.Ultrasound(US) is a well known widely used diagnostic technique for qualitative imaging
of soft tissues such as the prostate. Recently, a quantitative 3D US system
was introduced (Clarity system, Resonant Medical, Canada). Before introducing the device into daily practise, inter- and intra-operator variability, during both image acquisition and matching procedures, must be determined.
In this study we determined the inter- and intra-operator variability of 3D US
matching in prostate cancer patients. Moreover, we studied the influence ofscan re-scan variations, and the influence of inter-operator probe pressure on
the prostate position while using a strict bladder filling protocol.
Materials: The Clarity 3D US system consists of two US systems, i.e.
one in the CT room (US-Sim) and another one in the treatment room (USGuide).The US-Sim scan (reference) is fused to the planning CT and radiation
beams are imported. At treatment time, the US-Guide scan is matched to thereference US-Sim scan and the patient is shifted in three directions to realignthe target with the radiation beams.The system itself has a combined uncertainty of 2 mm for the whole quality assurance procedure (i.e. image tracking,image fusion). For 12 prostate patients US scans are acquired every otherday during treatment. The chronology of the measurements is illustrated in
the figure.The repeated scans are, per patient, matched by one single user
(variability for scanning). The remaining scans are matched three times bydifferent users, and for each patient one single scan is matched five times by
the same user (variability for matching).

Purpose: The BrainLab ExacTrac (v.5.5.2) image guidance system for radiotherapy verification assesses set-up errors in 6 degrees of freedom (6DOF).
Phantom studies have demonstrated sub-millimetre accuracy when using
bony anatomy or internal fiducial markers (FM) for matching purposes. This
study investigates the immediate residual errors post correction using ExacTrac stereoscopic image verification for patients undergoing prostate radiotherapy (RT) with internal fiducial markers (FM).
Materials: Thirteen patients each had 3 FM inserted prior to RT planning.
Seven hundred thirty-four stereoscopic image pairs were acquired pre- andpost-correction, prior to treatment. On-line automatic image registration was
performed daily, and corrections applied using FM position for registration.
Automatic bony registration was performed retrospectively.
All translationaland rotational errors were recorded. Systematic () and random (σ ) errors
post-correction were determined for bone and FM matches. The prostate
position relative to bony anatomy pre- and post-correction was calculated todetermine the contribution of prostate motion to residual error for each translational and rotational axis using the formula:(pre-correction (FM error - bonyerror)) - (post-correction (FM error - bony error)). Time for image acquisition, correction and re-imaging was correlated with FM residual and prostatecontribution residual errors using Spearman’s rank correlation coefficient inpatients whose first post-correction image was within tolerance (≤3mm/o ).
Results: The table below shows post-correction setup errors with FM registration and the extent to which prostate motion contributes to this. Timing
was not associated with residual FM errors or with the residual errors due toprostate motion.

Conclusions: Prostate motion accounts for the majority of the residual errors
found after FM registration, but does not explain all residual errors identified.
There was no clear correlation between residual errors and time in patientsrequiring application of one shift. Other factors including correction-induced
patient motion, inaccuracies of the image registration algorithm and mechanical limitations may also contribute. These factors must be considered whenassessing margin reduction and are under further investigation.
1258 poster
SETUP ERROR EVALUATION FOR BREAST CANCER PATIENTSDIVIDED IN THREE CATEGORIES; RESULTS OF PROSPECTIVEDAILY MATCH DATA
M. Baker1 , W. Ottosson1 , D. Klitgaard1 , K. Andersen1 , S. Lind1 , N. Hviid1 ,V. Brandhof1 , P. Toft-Jensen1 , P. F. Geertsen1 , S. Vallentin1 , M. Riise1 , D.
Sjöström1
1
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Oncology,
Herlev, Denmark
Results: In the graphs, the results for 3 (to 4) out of 12 patients are shown.
Graph 1 shows the intra-operator differences. In all three directions thelargest mean difference is 1.7 ± 1.5 mm. The largest mean inter-operator
difference (Graph 2) is of the same order, 1.9 ± 1.2 mm.The prostate displacement due to the probe pressure (Graph 3) varies from patient to patientand is, in our patient population, not limited to one direction. Looking at thecomplete patient population, no obvious trend in prostate displacement wasobserved. Only the superior/inferior displacement seemed significant for highpressure. However, in most cases low pressure was sufficient to obtain good
image quality with our bladder filling protocol, without improvement by extra
pressure.
Conclusions: The combined uncertainty (system accuracy, user variability)of the 3D US IGRT system is comparable to the uncertainty of an electronic
portal imager in combination with fiducial markers (about 5 mm).

Purpose: To quantify the systematic and random setup errors in breast cancer patients based on daily image acquisitions by means of electronic portal
imaging device (EPID). The main purpose is to compare the obtained result
for the three different categories. The aim is also to assess the clinical correction action levels based on various imaging protocols.
Materials: In the current approach the magnitude and directions of random
and systematic deviations in radiation therapy for breast cancer patients are
addressed. The encompassed patients (now 10 out of 30 patients) have been
divided in three categories; 1.Tangential breast/chest wall (n=10), 2. Chest
wall inclusive axilla and periclavicular lymph nodes (n=10), 3. Deep inspiration breath hold gating patients (left-sided breast cancer) of both types 1 and
2 (n=10). The initial patient setup was performed, according to a thoroughly
written protocol, where the side-tattoos were checked to a ruler, mounted on

S 469

the edges of the CT- and accelerator couch. This method supports setup reproducibility in superior-inferior (SI) direction from CT to accelerator and also
to the subsequent fractions. The thorax wall and clavicular bone structure
were matched to the reference DRR images with zero tolerance. Furthermore
a skin-tattoo in the new isocentre position was marked, which was later utilized as a reference for the subsequent fractions.The collected matching data
was analyzed, where the systematic and random setup errors were quantified in anterior-posterior (AP), SI, and left-right (LR) directions, respectively.
Eventually, the clinical correction levels, based on various imaging protocols,
were investigated.
Results: For the overall mean systematic and random setup errors were 1.3± 2.2 mm and 1.7 ± 0.6 mm in AP-directions, 0.0 ± 2.0 mm and 2.2 ± 0.8
mm in SI-directions, and -0.1 ± 1.2 mm and 1.5 ± 0.5 mm in LR-directions,
respectively. Individual systematic setup errors greater than 5 mm was observed in only 1 out of 10 patients (10%) in AP-direction. The displacementsin AP-, SI- and LR-directions that exceeded 5 mm were 12%, 12%, and 3%
and for the value 3 mm were 38%, 22%, and 14%, respectively.Update of
the presented statistical data, comparison among the calculated setup errors
for the various categories, and finally determination of the clinical action levels based on various imaging protocols will be presented, once the entire 30
patients have accomplished their treatment courses.
Conclusions: Recent study shows that the overall systematic errors for thematches are smaller than 2 mm, and for the random error is smaller than 3
mm for the breast cancer patients. It has also been observed that subsequent
EPID-imaging for four fractions is as accurate as daily setup imaging. No any
significant differences were observed for the three categories.
1259 poster
THE EFFECTIVENESS OF ON-LINE POSITION VERIFICATION OF
PROSTATE RADIOTHERAPY IN THE FLAME TRIAL
A. Kotte1 , S. Franken1 , M. van Vulpen1 , U. van der Heide1
1
U.M.C. U TRECHT, Radiotherapy, Utrecht, Netherlands
Purpose: To improve local control in prostate cancer, a dose escalation in
the dominant lesion inside the prostate is currently tested in a phase III randomized trial (FLAME trial). In the experimental arm, the dose to the GTV isescalated to 95Gy, under the condition that normal tissue tolerances are notexceeded. Since tumors are often localized at the dorsal side of the prostate,a high boost dose is delivered in close proximity to organs at risk. Therefore
accurate positioning of the target is mandatory. In this study, we evaluatedthe effectiveness of on-line position verification and the influence of remaining positioning deviations on the delivered dose.
Materials: We have calculated the intra-fraction motion for 34 patients. Patients were implanted with three gold markers. Patient positioning was doneusing a two field on-line marker detection procedure. During treatment, fields
from five treatment angles are used for position verification. From the obtained marker locations, the intra-fraction movement was calculated.
The marker detection is done using in-house developed software. From theresults, the intra-fraction range of motion can be calculated.
For the 18 patients from the high dose arm, the delivered dose is analyzed.
Taking marker position variation into account, an estimate of the delivered
dose was calculated.
Results: The average (standard deviation) time for the on-line procedure (neglecting the initial patient setup) was 4.1 (0.5) minutes while the rest of thetreatment took 7.3 (2.0) minutes on average.
The positioning figures (AP,RL,SI) are: mean systematic error M=(0.0,0.5,0.3)mm;
sytematic error S=(1.1,0.6,1.0)mm; random error s=(1.7,1.1,1.4)mm
The median range of motion for timepoint one was 2.1mm which increases toa value of 3.8mm towards the end of the fraction.
The analysed dose parameters are displayed in Figure 1. Every parameter
was calculated for the planned dose (white box) next to the estimated delivered dose (grey box). Also, we found for rectum, the median V72Gy increased
from 4.4% to 4.5% while for bladder the median V72Gy decreased from 4.5%
to 4.2%.

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IGRT: VOLUME DEFINITION , TREATMENT MARGINS AND GEOMETRIC UNCERTAINTIESIGRT: T REATMENT DELIVERY AND PATIENT POSITIONING
1261 poster

1262 posterTONGUE POSITION AND SETUP REPRODUCIBILITY USING
DIFFERENT TONGUE DEPRESSORS IN H&N CANCER ASSESSEDWITH CBCT.
S. van Beek1 , D. Minkema1 , P. Remeijer1 , J. J. Sonke1 , C. Rasch1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands

USE OF KILOVOLTAGE CONE BEAM CT (KV-CBCT) IN THE IMRTAND VMAT TREATMENTS OF NASOPHARYNGEAL CARCINOMA:
SET-UP ERRORS ANALYSIS
V. Mongioj1 , M. Franceschini2 , E. Orlandi2 , C. Stucchi1 , G. Zonca1 , C.

Purpose: In our institute head and neck cancer patients with a target volume
close to the oral cavity are setup with a thermoplastic mask and a tongue
depressor (figure 1a,b) to increase the distance between the tongue/floorof mouth and the palate. Within this patient group, repeat Cone Beam CT(CBCT) imaging revealed difficulties concerning the (re) placement and grip(with the jaws) of the perspex tongue depressor, leading to a poor reproducibility of the tongue and the jaws, followed by accuracy loss during radiation treatment. We therefore developed a new tongue depressor and tested
different attachment options (above and below the thermoplastic mask) andcompared it with the previously used tongue depressor. The purpose of thisstudy was to identify the most effective tongue depressors and to assess theeffect on reproducibility of surrounding patient anatomy.

Conclusions: The on-line procedure takes a significant amount of time. During this time, the intra-fraction motion is considerable.
Nevertheless, using this positioning scheme, it is possible to deliver such ahigh dose to the prostate without compromising the dose constraints for the
nearby organs at risk.
1260 poster
THE INFLUENCE OF RECTAL FILLING ON RECTAL DISPLACEMENT
AND ITS IMPACT ON DOSIMETRY WITHIN THE PTV
Z. Jani1 , N. Rosenfelder2 , M. Humphreys2 , H. McNair3 , K. Burke1 , D.
Berstein1 , N. van As3 , V. Khoo1
1
R OYAL M ARSDEN H OSPITAL, Department of Radiation Oncology, London,
United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of Radiation
Oncology, London, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Department of Radiation
Oncology, Sutton, United Kingdom
Purpose: To investigate the effects of rectal filling on organ motion within thepelvis, and its impact on dosimetry in patients receiving radical radiotherapy
to the prostate.
Materials: Cone Beam CT (CBCT) scans for 20 prostate patients (150 scans)having radical prostate radiotherapy were evaluated retrospectively. Scans
were acquired on fractions 1-3 and weekly thereafter. The rectum was outlined, according to local protocols, on the CBCT scans to analyse variation inrectal filling during treatment. The changes in rectal filling over the course oftreatment were measured and correlated with the volume of rectum within the
Planning Target Volume (PTV) defined on the planning CT scan. The change
in rectal dose was recorded using Dose Volume Histograms (DVH) produced
for each data set and the volume of rectum receiving 50Gy and 70Gy of dose
was recorded. As it was difficult to delineate the prostate on the CBCT scans,due to poor image quality, the displacement of the rectum was used as asurrogate for prostate movement within the PTV.
Results: A total of 150 scans were analysed, all providing satisfactory visualisation of the rectum for the purposes of the study. Of the scans analysed,
57% (11 out of 19) patients had a slightly lower mean rectal volume than theoriginal rectal volume. Rectal variation was higher for the cranial comparedto the caudal section. In a large number of scans with an increased rectal
volume, change in volume had increased due to air rather than solid matter.
By using the Spearman’s Rank correlation, this was found to be a correlation
coefficient of 0.6 for the volume of overlap of the rectum and the PTV andr=0.3 for the overlap between the rectum and 95% isodose. No correlation
was found between the rectal volume and the V50, but a small correlation
with V70 (r=0.4). Displacement of the rectum into the high dose volume wasassumed to displace the prostate anteriorly but was found to be within the
PTV.
Conclusions: Rectal volume tended to decrease towards the end of treatment, but changes in the V50 and V70 of the rectum were not significant.
There was a correlation between an increase in rectal volume and the volume of overlap of the PTV and rectum and the 95% isodose. Unexpected
increases in rectal volume were mainly due to gas in the rectum. . Further investigation into maintaining rectal volumes, using laxatives and enemas should be investigated including methods of daily image guidance suchas adaptative radiotherapy or fiducial tracking.

Figure 1. The tongue depressors: Perspex (a) and the new developed tongue
depressor (b) and the position of distance measurements (c): half way mouthcavity from upper jaw till tongue depressor (A) and upper jaw till "tip" end of
tongue depressor (B).
Materials: 374 CBCT scans of 47 patients (average of 8 scans per patient)were evaluated. For each patient, the distance (figure 1c) between the upper jaw and tongue depressor (distance A) and the upper jaw and tip of the
tongue depressor (distance B) were measured in the CBCT scans. The difference between the measurements in the planCT and CBCT scans was calculated (∆A and ∆B). Second, bony anatomy registrations using 3 sub regions(upper jaw, lower jaw and cervical vertebrae 1 till 3) were performed within 30
patients (n=10 per group). The patients were divided in 3 groups: 1) patientswith the previously used tongue depressor, 2) patients with a new tongue
depressor normally attached and 3) patients with the new tongue depressor
placed entirely below the mask for improved fixation.
Results: The group mean (M) differences in distances during treatmentcompared with the planCT ∆A/∆B were 0.01/-0.11 cm, -0.12/-0.16 cm and0.10/0.09 cm, for group 1,2 and 3 respectively, which were not statisticallydifferent. For individual patients, however, group 3 produced the smallest
systematic differences. The systematic errors (S) for ∆A/∆B were 0.25/0.66
cm, 0.36/0.40 cm and 0.17/0.22 cm, for group 1,2 and 3 respectively. The
difference (distance A) between group 1 and 3 was significant (p = 0.039).
Group 3 also showed the smallest random errors. The random errors (s)for distance ∆A/∆B were 0.25/0.51 cm, 0.25/0.35 cm and 0.11/0.20 cm, forgroup 1,2 and 3 respectively. No difference was found for the local setup errors in the bony sub regions between the 3 tongue depressor groups. The
M, S and s of the local setup errors were within 0.2 cm in all directions for all
three groups.
Conclusions: Improvement in reproducibility was found for the soft-tissue(tongue) due to the new developed tongue depressor placed below the fixation mask However, no improvement in setup reproducibility for the bonystructures was found. Therefore the new tongue depressor placed below themask has become our clinical standard.

Sangalli2 , G. Carabelli2 , C. Fallai2 , E. Pignoli1
1
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Medical Physics,
Milan, Italy
2
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Department ofRadiation Oncology, Milan, Italy
Purpose: To evaluate set-up accuracy by the use of kV-CBCT (3D technique)guidance in IMRT and VMAT treatments of nasopharyngeal carcinoma (NPC)
patients and to compare them with those measured by means of an Electronic
Portal Imaging Device (EPID, 2D technique).
Materials: Image-registration technique accuracy was evaluated acquiring
2D and 3D kV images of an anthropomorphic head phantom. Displacementsof 5 mm were also simulated by shifting the linac couch in the three orthogonal directions, as well as out of plane rotations were simulated by positioning
a wedge under the phantom head holder (5 degrees) along A-P and L-R
directions. Fourteen consecutive patients with non-metastatic NPC were included in this study. All patients were immobilized with a thermoplastic mask
covering head, neck and shoulders. Isocentre verifications were performedby means of on-board imager (OBI, Varian Medical Systems).KV-CBCT was
obtained before treatment every day, during the first week of treatment and,at least, twice a week thereafter. Displacements errors were expressed astranslations along the three axis: left-right (L-R), superior-inferior (S-I) andanterior-posterior (A-P). A 3 mm threshold was chosen as action level according to our previous experience with EPIDs. Patients mean displacements
were recorded by kV-CBCT, and population systematic (S) and random (s) errors were calculated according to the definitions reported by Bijhold and De
Boer. Finally, a comparison with displacements distributions previously obtained by means of EPIDs was performed.
Results: The phantom studies showed that the accuracy in the displacements evaluation was less than 1 mm along the 3 axis for both 2D and 3D
technique, when only translation movements were applied. On the contrary,when rotations were applied, the 2D approach was able to highlight only rotations along A-P direction, whereas the kV-CBCT could recognize the rotations
in both directions.Patients displacements were measured by the kV-CBCT acquiring 196 scans (mean 14, range 11-18 scans each patient). Set-up errors
were less than or equal to 3 mm in 94% of cases and mean errors were 0.3
mm, 0.6 mm and 1 mm in L-R, S-I and A-P directions respectively.EstimatedS values were 0.9 mm in L-R, 0.8 mm in S-I and 1 mm in A-P directions.
Whereas, the estimated s values were 1.5 mm in L-R, 1.6 mm in S-I and 1.8
mm in A-P directions. In comparison with S and s values estimated by 2D
technique, kV-CBCT allowed to reduce up to a 20% the systematic errors.
Conclusions: Phantom studies allowed to quantify the limits of the two different approaches, highlighting the advantage of kV-CBCT. Finally, the patient
data showed how the kV-CBCT was able to reduce the systematic errors, as
well.
1263 poster
USING EXACTRAC FOR ACCURATE POSITIONING OF BREASTCANCER PATIENTS
L. ter Beek1 , F. Wit1 , M. Immink2 , B. Geelen3 , C. van der Zaan1 , D. Hugen1
1
R EINIER DE G RAAF G ROEP, Department of Radiotherapy, Delft, Netherlands
2
L EIDEN U NIVERSITY M EDICAL C ENTER (LUMC), Division of Radiotherapy,
Leiden, Netherlands
3
R EINIER DE G RAAF G ROEP, Radiation Physics, Delft, Netherlands
Purpose: Brainlabs ExacTrac is a system for online patient position verification, using two perpendicular kV X-ray imagers. Most Exactrac installations
have been part of a Novalis system which is targeted for stereotactic treatments. As a consequence the system has been used world wide for only few
treatment sites (mainly cranial and lung). The purpose of this study was to investigate the feasibility of using ExacTrac to accurately position breast cancer
patients, and to improve the accuracy of on-line position verification.
Materials: We have evaluated matching the booster field on the implanted
clips, and matching the large breast fields on the thoracic wall. We included
15 patients. All of whom had ’medium’ clips implanted (Ethicon Endo-surgery,Ligaclip).Conventionally breast fields are positioned by matching on bonystructures in portal images, or in case of booster fields by using simulator
based lines on the patient skin, as clips are not visible in portal images.
The advantage of using ExacTrac is that clips are clearly visible on kV images.As a first step we have shown by phantom measurements that matching
on clips gives excellent results. The next step was to prove that this method is
also feasible in clinical practise.For all patients we let ExacTrac calculate thebooster field shift both before and after each treatment, and compared this tothe lines on the patient. The large breast fields were matched on the thoracic
wall using ExacTrac, both at the beginning and end of each treatment. These
we compared with matching on portal images.

S 471

Results: For the booster fields the results are excellent, and comparable
to the phantom results. Breathing of the patient did not present a problem.
There was no significant migration of the clips during the treatment. Table 1ashows the evaluation of the movement of the clips during the treatment.For
the large fields table 1b shows the results of the difference in the match on
the thoracic wall at the start and at the end of each treatment, this being an
indication of breathing and movement during the treatment.

Conclusions: It is feasible to use the ExacTrac system for the matching of
the clips in booster field treatments. For the large fields preliminary results
look promising. Final results are expected to be available soon. Breathing of
the patient, and migration of the clips did not appear to be a problem during
the match.

IGRT: Volume definition, treatment
margins and geometric uncertainties
1264 poster
4D CT-BASED PTV DEFINITION FOR LUNG TUMOURS: COMPARISON WITH CONVENTIONAL 3D-CRT USING INDIVIDUAL MARGINS
P. Antognoni1 , P. Barbieri1 , A. Bruni1 , E. Cenacchi2 , P. Ceroni2 , P.
Giacobazzi1 , G. Guidi2 , B. Lanfranchi1 , E. Mazzeo1 , B. Meduri1 , M.
Parmiggiani1 , G. Tolento1 , E. Turco1 , T. Costi2 , F. Bertoni1
1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Radiation Therapy,
Modena, Italy
2
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Physics, Modena, Italy
Purpose: To investigate the dosimetric and clinical benefit of the integrationof 4D-CT in the planning target volume (PTV) definition process compared
to conventional PTV definition using individual margins for radiotherapy (RT)treatment of lung tumour lesions
Materials: We evaluated the impact of 4D-CT planning in reducing PTV margins in 12 treatment plans of 10 patients (pts) planned with 4D CT and treatedwith IG-IMRT Tomotherapy for pulmonary tumour lesions between March andNovember 2010. Five out of 10 pts had a primitive lung tumour (3 squamouscell carcinoma, 1 large cell, 2 adenocarcinomas, 1 small cell); the others
where oligometastatic pts (2 from rectal and 1 from anal cancer, 1 from Wilms
tumour). All pts had a 4D-CT planning and two different GTVs and PTVs were
defined: GTVconv and PTVconv consisting of the helical CT-based CTVs expanded isotropically for each spatial direction (1 cm), such as we usually do
for conventional 3D planning. GTVsum and PTVsum were identified: PTVsum were obtained giving to the GTVsum an isotropic expansion of 5-7 mm.
All the oligometastic pts received an hypofractionated RT regimen. Volumetricdifferences and relations of both GTVs and PTVs were evaluated. Acute toxicity was analyzed for all pts and reported according to RTOG/EORTC scoring
systemResults: Volumetric examinations revealed a reduction of the mean CTV andPTV by 4D-CT from 148.8 ml to 88.8 ml and from 250.5 to 143.6 ml (> 50%),
even if the mean GTV was 26% bigger in the conventional 3D-GTV. In the palliative setting all constraints to spinal cord, ipsilateral and contralateral lung,heart and oesophagus were widely satisfied with 4D-CT based plans. Dmax
to spinal cord ranged from 0.39 Gy to 42.17 Gy (mean dose 19.1 Gy). Mean
dose to the heart was 6.4 Gy. No patients had Grade 3 or 4 lung, mucosal
or skin acute reactions. Three pts experienced Grade 1 asthenia, 1 pt Grade2; one patient had Grade 2 and three patients had Grade 1 esophagitis anddysphagia
Conclusions: The implementation of 4D-CT planning in the clinical routine
could result in a higher precision in the contouring of main treatment volumes
for intra-thoracic tumour lesions, achieving a better sparing of normal tissues
and a subsequent reduced probability of side effects

S 472

IGRT: VOLUME DEFINITION , TREATMENT MARGINS AND GEOMETRIC UNCERTAINTIESIGRT: VOLUME DEFINITION , TREATMENT MARGINS AND GEOMETRIC UNCERTAINTIES

1265 poster
A RADIOBIOLOGICAL CONSIDERATION OF LIKELY BENEFITFROM IMPLEMENTATION OF PROSTATE IGRT WITHOUT MARGIN
REDUCTION
S. Tudor1 2 , Y. Rimmer13 , M. Cowen2 , S. Thomas1 2
1
C AMBRIDGE U NIVERSITY H OSPITALS NHS F OUNDATION T RUST, Cambridge, United Kingdom
2
U NIVERSITY OF C AMBRIDGE, Department of Oncology, Cambridge, United
Kingdom
3
W EST S UFFOLK H OSPITAL, Bury St Edmunds, United Kingdom
Purpose: To determine the likely benefit from introduction of IGRT to prostateradiotherapy practice with current CTV-PTV margins of 5-10mm delivered either concomitantly or in two phases. Also to determine the feasibility of a potential clinical trial to resolve the expected difference in TCP between IGRT
and non-IGRT arms for these margin sizes.
Materials: Real systematic error data collected from 50 patients undergoing
daily fiducial marker localisation was used together with a random error ofσ =3mm to model non-IGRT treatment. IGRT was modelled with residual systematic and random errors of Σ=σ =1.5mm. Motion of the target relative to astationary dose distribution was simulated in a computer model and the TCPof the motion-affected dose distribution calculated. Population TCP was calculated for two 3DCRT techniques: two-phase and concomitant boost, bothof which had ostensibly the same target volumes and dose prescription. A
sensitivity analysis was performed with respect to TCP model and parametervalues. The relative field sizes of the treatment techniques were examined to
inform discussion of the difference between them. The distribution of systematic errors and correlations between movement axes were also examined todetermine the validity of assumptions of conventional margin recipes applied
to this treatment site.
Results: For the two-phase and concomitant boost techniques the differences in TCPpop between the IGRT and non-IGRT regimes were 0.3% and1.5% respectively. A two-phase plan, where each phase conforms the 95%
isodose to its respective PTV, requires fields approximately 3.5mm larger thanrequired for the concomitant boost plan. Despite the larger field sizes, theTCP (without IGRT) is only 1.7% higher in the two-phase plan. The deviationof craniocaudal systematic errors (p=0.02) from a normal distribution, andthe correlation of translations in the craniocaudal and anterioposterior directions (p<0.0001) were statistically significant. The sensitivity analysis reveals
no significant change in the qualitative observations in the main study for avariety of model parameters.

with in-treatment CBCT images successfully acquired during VMAT delivered
by Synergy (Elekta) were analyzed. The displacement during treatment wasevaluated by cross correlation between pre- and in-treatment CBCT images
considering automatic couch correction. The VMAT plan was created by Pinnacle v9.0 for 13 patients and by Monaco v2.03 for 2 patients.
Results: Figure 1 shows 3D-plot of the displacement during treatment for first
15 fractions. There were 8 and 2 cases where the displacement exceeded
3mm in vertical and longitudinal directions, respectively, while the displacement in all cases was less than 2.5mm in lateral direction. It was observedthat the displacement in vertical direction was relatively large mainly owing toa poor accuracy in automatic couch correction to this direction. With mechanical errors caused by the difference of isocentre between kV and MV beams
and the isocentre shift during gantry rotation, margins less than 4mm wererequired in all patients. The treatment time of VMAT was 140.8 sec on average. The treatment time of Monaco plan was about 70 sec longer than thatof Pinnacle. However, this fact seems not to affect on the image registrationand the margin estimation.

1268 poster
CHANGES AND DEFORMATIONS OF THE CORPUS UTERI DURING
A COURSE OF RADIOTHERAPY FOR CERVICAL CANCER
K. L. Jakobsen1 , C. F. Behrens1 , H. Johannesen2
1
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Oncology,
Herlev, Denmark2
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Radiology,
Herlev, Denmark
Purpose: The aim of this project is to evaluate the quality of CBCT-scans andto quantify the changes in the position of uterus during a course of radiotherapy.The hypothesis is that these changes are so dominant that some patientsshould be rescanned and replanned during the treatment course.
Materials: Thirty patients with cervical cancer and weekly CBCT-scans were
included. A radiologist (HHJ) retrospectively outlined the cervix and corpus
uteri on the CBCT-scans and the sizes of the delineated volumes were analyzed.The outline was done in Eclipse 8.8 (Varian Medical Systems, Pal Alto,
Californien). The CBCT-scans were acquired without contrast with 125 kV
and 1040 mAs on Varian iX machines.
Results: As the tumor shrinks so does the cervix and this can result inchanges in the position of the corpus uteri. The daily differences in the bladder and bowel filling further changes the position of corpus uteri. For somepatients dramatically changes of the irradiated volumes were observed.In
general it was hard to distinguish between the different organs on the CBCTscans. Specifically it was difficult to distinguish between cervix and corpus
uteri and between the lower part of cervix and the vagina.For a few patients the corpus uteri underwent large changes concerning size, positionand shape. This is partly due to retention: The tumor in cervix has initiallyformed a plug and as the tumor shrinks the uterine cavity empties itself (seefigure 1).

Conclusions: The uncertainties of patient setup for prostate cancer patientswere observed by in-treatment CBCT images, which are most reliable in an
evaluation of displacement during treatment. The introduction of patientspecific margin may allow further margin reduction.
1267 poster
ANALYSIS OF THREE-DIMENSIONAL SET-UP UNCERTAINTIES IN
HEAD AND NECK 3D CRT
B. Štrbac1 , Z. Kuzmanovic1 , A. Kostovski1 , M. Milakovic1
1
I NTERNATIONAL M EDICAL C ENTERS, Banja Luka, Bosnia and Herzegovina

Conclusions: The expected population benefit of IGRT for the modelled situation is too small to be detected by a clinical trial of reasonable size, although
there is a significant benefit for individual patients. Concomitant treatment
techniques allow for full accounting of dose from one set of beams in the optimisation of the size of the other, permitting considerably smaller fields andtighter dose conformality than two-phase treatments planned separately.
1266 poster
ANALYSIS OF PATIENT SETUP UNCERTAINTIES BY USING
IN-TREATMENT CONE-BEAM CT FOR PROSTATE CANCER
K. Shiraishi1 , A. Haga1 , S. Katsutake1 , N. Saotome1 , S. Kida1 , A. Sakumi1 ,T. Onoe1 , K. Yamamoto1 , K. Ohtomo1 , N. Keiichi1
1
T HE U NIVERSITY OF TOKYO H OSPITAL, Department of Radiology, Tokyo,
Japan
Purpose: The use of cone-beam computed tomography (CBCT) appears
to be inevitable for implementing a daily setup of precise radiation therapy.
However, the CBCT images before treatment (pre-treatment CBCT) may bedisplaced from the actual location during treatment. In order to evaluate atreatment margin, therefore, the ideal is to obtain image volume in the state
ofdelivered beams, and is called "in-treatment CBCT". The purpose of thispaper is to give a report on patient-specific setup variations via analysis within-treatment CBCT images during volumetric modulate arc therapy (VMAT).
Materials: Cone-beam CT images for 15 prostate patients were acquired
prior to and during treatment each time: A total of 450 treatment fractions

Purpose: The objective of the study is evaluation of geometric uncertainties in a population with tumor of head and neck region as necessary step
to develop strategy to reduce set-up and transfer errors during the course oftreatment in recently opened radiotherapy centre in Banja Luka, Bosnia andHerzegovina. Each clinic should measure its own systematic and random errors as a part of QA program of treatment delivery by the verification of treatment field’s positions to document the efficiency of immobilization method
and reproducibility of treatment.
Materials: The assessment of errors was done comparing two orthogonal portal images (PI) with Digitally Reconstructed Radiographs (DRRs) by
matching bone anatomy landmarks with anatomy matching software: Varian
Offline Review. DRRs were obtained from the CT simulator and considered
the reference images and portal images acquired were obtained using EPID
system attached to Varian linear accelerators. To establish an accurate estimate for all systematic and random errors, we analyzed 30 patients undergoing 3D conformal radiotherapy, head and neck region, with at least one
weekly image and overall 200 PI. 5-pt Orfit masks were used for patient immobilization. Mean displacements, population systematic and random errors
and 3D vector of displacement were calculated.
Results: The population systematic errors were less than 1 mm in the three
directions whereas the random set up errors were around 2 mm. PTV margins were in the range from 2 to 4 mm in the all three directions.
Conclusions: Each institution should review and quantify geometrical uncertainties in radiotherapy to reduce setup errors in clinical practice. The objective of present study is to conduct analysis of setup uncertainties of patients
receiving head and neck radiotherapy and to conduct QA aspect of treatment
delivery. The set up margins were <5mm in all three directions. A PTV marginof 5 mm appears to be adequate.

S 473

IMAGES
J. Li1 , J. Xing1 , Y. Zhang1 , F. Li1 , M. Xu1
1
S HANDONG C ANCER H OSPITAL, Department of Radiation Oncology, Jinan,
China
Purpose: To compare the position and magnitude of internal target volume (ITV) of the primary hepatocarcinomas delineated by the three methods basedon four-dimensional computed tomography (4D-CT) and to investigate therelative factors affecting the position and magnitude .
Materials: Twenty patients with primary hepatocarcinoma underwent big
bore 4D-CT simulation scan of the thoraxand abdomenassisted by real-time
position management (RPM) system for simultaneous record of the respiratory signals. The CT images with respiratory signal data were reconstructed
and sorted into 10 phase group in a respiratory cycle, with 0% phase corresponding to end-inhale and 50% corresponding to end-exhale. Maximum
intensity projection (MIP) image was generated. ITVs of the primary tumorof NSCLC were delineated using three methods as following: the gross tumor volume (GTV) on each of the ten respiratory phases of the 4D-CT image
set were delineated and fused ten GTV to produce ITV10;the GTV delineatedseparately based on 0% and 50% phase were fused to produce ITVIN+EX;thevisible tumor on the MIP images were delineated to produce ITVMIP. Twenty
patients were divided into A group and B group based on the location of thetarget center and were divided into C group and D group based on the tumor
D, the patients were divided into E group and F group based on the threedimensional (3D) motion vector of the target center. The position of the target
center, the volume of target, the degree of inclusion (DI) and the matching index (MI) were compared reciprocally between ITV10, ITVIN+EX and ITVMIP,
and the influence of the tumor position and 3D motion vector on the relative
parameters were compared based on the grouping.
Results: Average differences between the position of the center of ITVs on
direction of X,Y and Z axes were less than 1.5 mm, with no statistically significant difference. The volume of ITV10 was larger than that of ITVIN+EX , but
the difference was not statistically significant (t = 0.354P = 0.725), the volume
of ITV10 was larger than that of ITVMIP, but the difference was not statistically significant (t = -0.392, P = 0.697). The ratio of ITVIN+EX with ITV10,
ITVMIP with ITV10 were 0.75 ± 0.15 and 0.78 ± 0.14, respectively. DI of
ITVIN+EX in ITV10, ITVMIP in ITV10 were (74.85 ± 15.09)% and (68.87 ±13.69)%. MI between ITV10 and ITVIN+EX, ITV10 and ITVMIP were 0.75 ±
0.15, 0.67 ± 0.13, respectively. The median of ratio of ITVIN+EX / ITV10 was
0.57 in group A versus 0.87 in group B, the difference between group A andgroup B was statistically significantz = -3.300P = 0.001. the median of ratioof ITVMIP / ITV10 were 0.51 in group A versus 0.72 in group B, the difference
between group A and group B was statistically significantz = -3.413P = 0.001.
The median of ratio of ITVIN+EX / ITV10 was 0.79 in group C versus 0.74 ingroup D, with no statistically significant differencez = -0.920P = 0.358; themedian of ratio of ITVMIP / ITV10 was 0.85 in group C versus 0.80 in group
D, the difference was not statistically significantz = -0.568P = 0.570.The median of ratio of ITVIN+EX / ITV10 was 0.87 in group E versus 0.68 in groupF, the difference between group E and group F was statistically significantz =-2.897P = 0.004. The median of ratio of ITVMIP / ITV10 were 0.85 in group
E versus 0.81 in group F, the difference was not statistically significantz =-0.568P = 0.570.
Conclusions: The center displacement of the ITVs delineated separatelyby the three different techniques based on 4D-CT images are not obvious;
ITVIN+EX and ITVMIP can not replace ITV10, however, ITVIN+EX is moreclose to ITV10 comparing to ITVMIP. The ratio of ITV10 and ITVMIP is correlated to the 3D motion vector of the tumor. When the tumor in the upper partof the liver and with a 3D motion vector less than 9 mmITV10 should be theideal ITV.
1270 poster

Conclusions: It is difficult to distinguish between cervix and corpus uteri andbetween cervix uteri and vagina on CBCT-scans. Especially the position of
corpus uteri can change dramatically from day to day and during a treatment
course. The daily position changes are accounted for with the CTV to PTV
margin.The large deformations found in this study illustrate that a new CTscan must be acquired at some point during the course of treatment. The
CBCT-scans can point out the relevant time for this rescan.Weekly MR-scans
during radiotherapy would be advantageous. This will enable observation of
the decrease in tumor burden and other morphological changes. The possibility of reducing the target volume by using MRI as a diagnostic scan should be
investigated. The MRI allows better differtiation between tumor in the cervix
and corpus uteri and between the benign tissues (cervix, corpus uteri and thevagina).
1269 poster
COMPARATIVE STUDY BETWEEN THE THREE METHODS TO
DELINEATE INTERNAL TARGET VOLUME OF THE PRIMARY HEPATOCARCINOMA BASED ON FOUR-DIMENSIONAL CT SIMULATIONDOSIMETRIC IMPLICATIONS OF UNCORRECTED ROTATION OF
THE PROSTATE DURING EXTERNAL BEAM RADIOTHERAPY
K. Burke1 , C. Lamb1 , N. Rosenfelder1 , M. Bidmead1 , N. van As1 , V. Khoo1
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom
Purpose: 3D imaging of the prostate during external beam radiotherapy is
now routine, either via orthogonal 2D kV imaging of fiducial markers or directly using cone beam CT. Correction of translational set-up errors is routine
and can be achieved with a standard linac treatment couch. Dealing withrotational error (RE) is not so straightforward:Robotic tilting couch tops canonly correct small RE, typically up to 3◦ . In our clinic RE > 10◦ have been observed in some patients.Rotating the couch top may induce secondary patient
motion.As the prostate CTV is approximately spherical, it could be assumed
that not correcting rotations may have a relatively small impact on set-up. The
impact of this residual set-up error on dose coverage is not obvious however.
We therefore undertook a dosimetric assessment of prostate rotation to assess its clinical impact and to see if a tolerance value could be established forRE.
Materials: Ten patient datasets were selected for retrospective analysis.
Each of these patients had been implanted with a minimum of three fiducial
markers and had been imaged during treatment with an Exactrac (BrainLab)S 474

IGRT: VOLUME DEFINITION , TREATMENT MARGINS AND GEOMETRIC UNCERTAINTIESIGRT: VOLUME DEFINITION , TREATMENT MARGINS AND GEOMETRIC UNCERTAINTIES

system.For each patient the CTV (consisting of prostate plus base of seminal
vesicles) was rotated by 3, 5 and 10 degrees using in-house software. Rotations were applied in all three axes and were about the treatment isocentre. In addition to these standard rotations, for each patient the individual’smeasured mean rotational error plus one standard deviation was applied tosimulate a "typical" rotational set-up error (values ranged from -7.0 to +7.1
degrees). The rotated CTVs were then imported back into the TPS (Eclipse
v8.6, Varian). It was assumed that the seminal vesicles moved in tandem withthe prostate.A five field IMRT plan was then produced for each patient. Our
technique utilises a simultaneous integrated boost: PTV2 (CTV plus 3mm,
5mm anteriorly, excludes rectum) is prescribed to 74 Gy, with PTV1 (CTV
plus 10 mm, 7mm posteriorly) receiving 68 Gy. DVH data for each of therotated CTVs, plus the original clinical CTV, were extracted for analysis.
Results:

ongoing and it is expected that such co-registration will be important for futurestudies evaluating IMRT dose-escalation to the tumour. Further work using
deformable co-registration programmes needs to be undertaken to assess
whether this would improve accuracy significantly. Applied Functional MR tothis process would be investigated.1. Pipe J. PROPELLER MRI; application
to motion correction. 7th Scientific Meeting of The ISMRM, 1999.
1273 poster
IS DAILY IGRT NEEDED FOR PROSTATE PATIENTS?
S. Agergaard1 , H. Jensen1 , C. Brink12
Conclusions: Significant (>1 mm) inter-marker distance changes have been
observed during a course of post-operative radiotherapy. They are believed
to be due to inter-and intra-fraction deformation of the prostate-bed.

1

O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
DenmarkU NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark21272 poster

Conclusions: CTV coverage at the D98% level is adequate (> 95%) in theface of rotations of 5 degrees or less and this may be an appropriate tolerance
level. Minimum dose to CTV is adequate in the face of a 3 degree rotation but
drops sharply at 10 degrees. Mean, D98% and maximum doses show little
or no variation.These results suggest that our current margins are adequate
to compensate for uncorrected REs up to 5 degrees. Any future reduction of
margins would have to be evaluated in terms of the dosimetric impact of REs.
1271 poster
EVALUATION OF PROSTATE-BED DEFORMATION WITH IMPLANTED FIDUCIAL MARKERS DURING POST-OPERATIVERADIOTHERAPY OF PROSTATE CANCER
G. Pang1 , P. Au1 , P. Cheung1 , G. Morton1 , H. Chung1 , A. Deabreu1 , H.
Quon1 , A. Loblaw1
1
O DETTE C ANCER C ENTRE , S UNNYBROOK H EALTH S CIENCES C ENTRE,
North York, Toronto, Canada
Purpose: The objective of this study was to assess both inter-and intrafraction prostate-bed deformation during a course of post-operative radiotherapy.
Materials: Patients with histologically confirmed recurrent or high risk adenocarcinoma of the prostate post-radical prostatectomy were eligible for thisstudy (This is a part of a larger study aimed to assess the toxicities of delivering a hypofractionated accelerated course of adjuvant post-operative radiotherapy). Prior to CT simulation, 3 gold fiducial markers were implanted into
the prostate bed: one at the bladder neck (marker #1), one at the urogenital diaphragm (marker #2), and one near the bladder/urethra anastomosis(marker #3). At least one week after insertion of the fiducial markers, a planning CT scan was performed with the patient supine with a custom vacuum
lock bag for immobilization. Patients had a comfortably full bladder and wereasked to empty their rectum prior to simulation and each treatment. The radiotherapy involved delivering 51 Gy in 17 fractions to the prostate bed using
an optimized 7 field inverse planned IMRT technique. Before each fraction ofradiotherapy, AP and RT lateral electronic portal images (pre-treatment EPI)
were taken. The location of the centre of mass of three fiducial markers wasused for daily online correction for setup errors and interfraction organ motion,
while the change of inter-marker distance seen on the pre-treatment EPIs as
compared to that on DRRs was used to assess the interfraction prostate bed
deformation (and possible marker migration). Post-treatment electronic portal images (post-treatment EPIs) were also taken on days 1-6 and 11 andcompared to the pre-treatment EPIs to assess the intrafraction prostate-bed
deformation.
Results: So far five patients have been enrolled into the study with four ofthem whose EPI data (a total of 192 images) were available for analysis. It
was found that for all four patients significant (>1 mm) inter-marker distancechanges were observed in both inter-and intra-fraction cases. The maximum
inter-marker distance change observed was 5.7 mm in the interfraction caseand 3.6 mm in the intrafraction case. The area of the triangle defined by thethree markers was changed up to 27% between fractions and 17% during afraction. Table 1 shows the mean and the standard deviation (in bracket) of
the inter-marker distance change as well as the change of the triangle area
defined by the three markers for these patients.

HIGH QUALITY MRI-CT CO-REGISTRATION WITH T2-WEIGHTED
BLADE SEQUENCES FOR HEAD AND NECK RADIOTHERAPY.
J. Maclean1 , S. punwani1 , S. Morley2 , D. Marsh1 , K. Sullivan1 , S. A.
Moinuddin1 , C. Stacey1 , A. Bainbridge1 , D. Carnell1 , R. Mendes1
1
U NIVERSITY C OLLEGE L ONDON H OSPITAL NHS T RUST, London, United
Kingdom
2
U NIVERSITY C OLLEGE L ONDON H OSPITAL NHS T RUST, Department ofClinical Oncology, London, United Kingdom
Purpose: MRI is superior to CT at differentiating tumour from normal tissue
in the head and neck region. Target volumes are traditionally defined on CT
as electron density data directly derived from Hounsfield units are requiredfor plan dosimetry. Co-registration of CT and MRI would improve accuracyof target volume definition. We aim to develop an optimised head and neck
MRI-CT fusion protocol for use in our department and determine its accuracy.
Materials: A customised flat acrylic baseboard compatible for both MRI andradiotherapy planning CT scan was designed and manufactured in-house.
Body surface and flexible carotid coils were used in conjunction with the patients individualised thermoplastic (TP) radiotherapy head and neck shell. A
TP bridge was fitted over the shell to support the body surface coil. Fig 1.
3 healthy volunteers underwent MRI scan in the TP shell to establish thetolerability of the procedure and to clarify the quality of anatomic clarity . Tolerability and acquisition time of the MRI was evaluated in 8 patients with headand neck cancer due to undergo radical radiotherapy. In these patients, planning CT and MRI scans were performed on the same day. Images were fusedusing a rigid co-registration programme on Eclipse (Varian Medical Systems)
and the discrepancy between them was evaluated by measuring the rotations
required to co-register the images in 3D.

Purpose: Prostate motion - both inter - and intra-fractional - is a major causeof uncertainty in radiotherapy treatment of prostate cancer. The purpose ofthis study is to quantify inter- and intrafractional motion of the prostate by evaluating cone beam CTs (CBCT) obtained both prior to the treatment (prescan)
and after the treatment (postscan). By comparing day to day changes of theprescan the interfractional error can be calculated. The intrafractional error is
calculated as the difference between the pre- and postscan.
Materials: 39 prostate patients for which CBCTs were obtained at fractions
1-3, 10-12, 20-22, and 30-32 (referred to as triplets) were included in the
study. All patients had three gold seeds implanted in the prostate. The patients were positioned in a vacuum fixation bag extending from the knees
to the feet. No specific diet was prescribed. Each CBCT was registered
online to the planning CT by a manual seed match. Following a triplet thepatient was shifted by the mean correction vector if the norm of the vector exceeded 4 mm.Day to day differences for the prematch were used to calculate
both systematic and random errors of interfractional prostate movement. The
difference between the pre- and the postmatch was used to assess the intrafractional movement. By applying the van Herk formula [IJROBP 47, 2000,
1121] CTV to PTV margins were calculated for different scanning protocols:
No correction, correction based on first triplet, correction after each triplet,and daily IGRT.
Results: For intrafractional prostate motion the systematic error was foundto be 0.6 mm, 1.3 mm, and 1.3 mm for the LR, CC and AP axes respectively. Random errors were 1.0 mm, 1.8 mm, and 1.7 mm for the same axes.
For the interfractional errors a reduction of the systematic errors following thetriplet was observed. Following a triplet correction the systematic errors wereapproximately halved from ~2.5 mm to ~1.2 mm for all axes. However, thefollowing triplet revealed the systematic errors at the same level as before
the correction. The interfractional random error was 1.9 mm, 1.7 mm, and
1.7 mm for the LR, CC and AP axes respectively.The time development of
the systematic interfractional error is not clear currently. This uncertainty ofthe systematic errors makes it difficult to estimate CTV to PTV margins anda conservative approach is chosen in order to maintain target coverage. Including a 2 mm delineation error and summing both systematic and random
errors by squares, the full triplet scan protocol requires a margin of about 10
mm, which is slightly better than the 11 mm found for correction based on
only the first triplet. A no-correction-protocol requires a margin of 13 mm forfull target coverage, whereas a margin of 7.0 mm is sufficient if IGRT basedon CBCT is performed on a daily basis.
Conclusions: A large reduction of high dose volume is achieved by use of amargin of 7 mm compared to a margin of 10 mm, thus daily IGRT is needed
to obtain this reduction in radiated volume.
1274 poster
MANUAL SEGMENTATION (HOW ACCURATE ARE WE?) (ANALYSE
OF MANUAL SEGMENTATION ERROR)
A. Outif1 , M. Mosely1
1
K ING FAHAD M EDICAL C ITY, Medical Physics, Riyadh, Saudi Arabia

Results: The T2-weighted BLADE MRI sequence with 3mm slices provided the highest resolution images with excellent soft tissue definition forco-registration. BLADE is Siemens version of the PROPELLER (Periodically
Rotated Overlapping Parallel Lines with Enhanced Reconstruction) sequencewhich collects data to mitigate in-plane motion, through-plane motion andphase inconsistencies1 . The impact of involuntary patient motion, such as
swallowing, was minimised without requiring additional distortion correction.
All patients found the MRI scanning process acceptable and the median timeto acquire the MRI images was 5 minutes. Mean rotation required for coregistration was <1◦ in all planes: mean x = 0.529◦ ; mean y = 0.463◦ ; meanz = 0.44◦ .
Conclusions: Our method of CT-MRI image acquisition and co-registration
is tolerable and accurate. T2-weighted BLADE sequences provide excellent
image quality without the need for distortion correction. Evaluation of theclinical impact of this co-registration protocol on target volume definition is

Purpose: Target volume (and organs at risk) contouring remains a major
source of errors in radiotherapy. There are two main sources of delineation
errors. The first is related to the clinical knowledge of the physician which
can be limited by proper protocol and training. The second is technical error
associated with imaging and viewing technique. The aim of the current work
is to quantify such a technical error.
Materials: A cylindrical piece of plastic of 5.33 cm length, 0.96 cm diameter, was inserted in the pharynx of rando phantom. The phantom was CT
scanned on Siemens sensation open CT scanner. The scan was then reconstructed to 1.5 mm, 3 mm and 5 mm slice thicknesses. The resultant
images showed 170 HU for the plastic insert and -1000 HU for the pharynx
area. The scan was transferred to Varian VISION Systems. Eight physicians,
physicists and dosimetrists of minimum experience of two years were thenasked to manually contour the plastic insert. The volume of the contoured
insert was then estimated for each slice thickness and compared with the actual volume. The different error parameters affecting the accuracy of volume
estimation was assessed.

S 475

Results: Clear tendency of all operators to underestimate the volume of thestructure with as much as 54.4% was noted. This contouring error was systematic and resulted in clear one directional error. The reasons for such error
was analysed as follow: Partial volume effect was found to be responsible for
0.8 mm (-1.50%) for 1.5 mm slice thickness, 0.7 mm (1.31 %) for 3 mm slice
thickness, and 1.7 mm (3.19%) for 5 mm slice thickness. Linear correlationof % error showed that optimum slice thickness our case is 2.44 mm. Inappropriate selection of window level and width caused the operators to missone or more slices and this resulted in mean error of -5.34% (range from 8.57% for 3 missing slices to 0% for zero missing slice) for 1.5 mm slice thickness reconstruction, 9.72% (range from -16.67% for 3 missing slices to 0%
for zero missing slice) for 3 mm slice thickness reconstruction, and -10.22%(range from -18.18% for 2 missing slices to 0% for zero missing slice) for 5mm slice thickness reconstruction. Inappropriate setting of window width andlevel also affected edge delineation accuracy. Slice by slice edge delineation
error was found to be the most contributor to the overall error with mean error of -21.94% (range from -34.25% to 1.24%) for 1.5 mm slice thickness
reconstruction, -21.84% (range from -32.43 to 5.94) for 3 mm slice thickness
reconstruction, and -20.74% (range from -39.41% to 0.2%) for 5 mm slice
thickness reconstruction.
Conclusions: Although target delineation accuracy affected by both acquisition and viewing parameters, viewing parameters (selection of window widthand level) was found to be the most contributor to delineation accuracy. Development of accurate auto-segmentation algorithms is expected to improvedelineation accuracy.
1275 poster
PTV DELINEATION IN STEREOTACTIC BODY RADIATION THERAPYAN ANALYSYS OF OUR EXEPERIENCE
G. Totaro1 , E. Verga1 , P. Morrone2 , M. D. Falco3 , V. De Chiara1 , G. Martin1
1
C ENTRO M ORRONE, Caserta, Italy
2
C ENTRO R ICERCHE M ORRONE, Caserta, Italy
3
TOR V ERGATA U NIVERSITY OF R OME , P HYSICS D EPARTMENT, Rome, Italy
Purpose: The aim of this work is to make a comparison of two off line IGRT
strategies used in our experience for delineation of PTV stereotactic bodyradiation therapy
Materials: From 2009 to 2010, 18 patients received a SBRT.10 lung metastasis, 3 primitive lung tumor,2 retroperitoneal metastasis, 2 mediastinal linphonode metastasis and another hepatic metastasis. We used the Elekta
Body frame. All the patients performed a first CT scan (CT1) and after few
days a second CT(CT2). At the end of the CT2 , two TC (CT3 and CT4) in different respiratory phase were acquired.CT1 and CT2 scans were transferred
to TPS to find the stereotactic coordinate of isocenter and for contouring GTV.
Then, we transferred the ROIs (GTV) and isocenters from ERGO to a second
TPS (Pinnacle). were we fused the CT1 with CT2, CT3 and CT4 . On theCT1 , we delineated two PTVs for every patient. One PTV from GTV (PTV1)
using the values of the translations of the isocenter as defined in ERGO (witha minimum expansion of 5 mm in both axis even if the translations found wereless than this value ); the second PTV (PTV2) was obtained from the GTV delineated in the co-registrated images of the CT1, CTV2, CT3 and CT4 scansand expanding this new GTV with 5mm in all axis.
Results: Firstly, by evaluating the isocenter translations, we obtained : amedian translation of 1.1 mm, a maximum of 4.2 mm and a minimum of 0mm for X axis. For Y the median was 2.7 mm , the maximum 11.3 and theminimum 0.2 mm. For Z, the median was 5.1 mm, the maximum 11.9 mm
and the minimum 0.6 mm. These, shows a great reproducibility. A thoroughanalysis showed that the minimum translations is for the patients with two
retroperitoneal tumors (the isocenters translations: 0.2mm and 0.0 mm for X,
0.3 mm and 0.9 mm for t Y and 4 mm and 4.9 mm for Z. The others isocentertranslations, were not bigger than 1 cm in any. Secondly, we have investigated the difference of the PTVs in the two IGRT strategy. In retroperitoneum
lesions, the two PTVs showed no difference thanks to the small contributeof respiratory motion. In Hepatic lesion, the PTV2 was not took into accountbecause the target in the forced respiratory phase was to far away from thetarget in the free breathing CT (CT1). For lung lesions, the PTV2 contours
were always bigger than PTV1
Conclusions: Our results show that the IGRT strategy using fused TC images gives margins too big on lung lesions, whereas these margins can beconsidered conservative. This can be adducted to the contribute of the forced
respiratory phase not present in normal breath. On the other end, the otherstrategy with small margin can miss part of target if a great position error occur. Finally, none of this strategy seems the ideal tool. Clinically, we decided
to adopt the technique of fused TC scans only for small lesion (less then 2,5
cm of diameter) where a bigger expansion to PTV don’t cause a severe side
effect on lung. The other technique, is the best choose when the target ismore than 2,5 cm.
1276 poster
RADIOTHERAPY OF HODGKIN LYMPHOMA: A NON-RIGIDREGISTRATION BASED METHOD FOR SEMIAUTOMATIC CTVS 476

IGRT: VOLUME DEFINITION , TREATMENT MARGINS AND GEOMETRIC UNCERTAINTIESIGRT: VOLUME DEFINITION , TREATMENT MARGINS AND GEOMETRIC UNCERTAINTIESLOCALIZATION
M. F. Spadea1 2 , L. L. Travaini3 , P. Zaffino1 , M. Ferrari3 , R. Orecchia4 , G.

registered with the Preop-CT and the boost-CTV was delineated again on
the Plan-CT (boost-CTV-2).To study the impact of the Preop-CT on the delineation of the boost-CTV, we calculated the delineated volume of both boostCTV-1 and boost-CTV-2. Subsequently, we calculated for each patient, foreach observer pair and for both boost volumes, the conformity index (CI =(common volume) / (encompassing volume)) and the distance between thecentres of mass (COMd). Finally, for each patient and both boost volumes,
the standard deviation (sd) histogram of all delineations with respect to themedian delineation was calculated. The volume, CI and COMd where compared between the datasets with and without a Preop-CT using Wilcoxon
tests; the sd histograms using a Mann-Whitney test.
Results: With a Preop-CT, the delineated volume decreased significantly,
with the average decreasing 5.7cc (see table). The Mean CI did not change
significantly, but the COMd showed a significant decrease with the average
decreasing 1.5mm. For 46% of the patients the sd decreased significantly
from on average 0.64mm to 0.49mm, whereas for 19% the sd increased significantly from on average 0.51mm to 0.70mm. See the figure for an example.While the observers mostly agreed on the GTV delineation, we observeda disagreement of the GTV for 3 patients. Since improved consensus is only
expected if there is consensus on the GTV, the analysis has been repeated forthe twenty-three patients for whom this was the case. For this subgroup there
is a significant increase in CI and the improvement in COMd has increased
to 2.2mm. The proportion of patients with a significant decrease in the sd
increased slightly to 52%, while the proportion of patients with a significant
increase in the sd decreased slightly to 17%.

Baroni2U NIVERSITÀ DEGLI S TUDI M AGNA G RAECIA, Department of Experimental
and Clinical Medicine , Catanzaro, Italy
2
P OLITECNICO DI M ILANO U NIVERSITY, Biomedical Engineering, Politecnico
di Milano, Milano, Italy
3
E UROPEAN I NSTITUTE OF O NCOLOGY, Nuclear Medicine Division, Milan,
Italy
4
E UROPEAN I NSTITUTE OF O NCOLOGY, Department of Radiation Oncology,
Milan, Italy
1

Purpose: The standard clinical practice for Hodgkin Lymphoma (HL) treatment is to perform chemotherapy followed by radiotherapy. According tocurrent guidelines, the clinical tumor volume (CTV) corresponds to the involved lymph nodes revealed by standard techniques at baseline, not always
clearly visible on post-chemotherapy Positron Emission Tomography (PET)and Computed Tomography (CT). The aim of this work is to develop a nonrigid based method to guide radiotherapist in delineating the CTV through theinitial PET baseline data.
Materials: The method involves the following steps:
1. Delineate CTV on pre-chemotherapy CT/PET images;

S 477

ranged from 5 to 31cm3 . The PTVgating (ranging from 12 to 83cm3 ) was, on
average, 45% smaller than PTVnogating (ranging from 18 to 135cm3 ). There
was no significant difference in tumor coverage between the two plans. Meanlung dose was 6.6Gy and 4.0Gy, on average, respectively for the non gated
and the gated plan; V20 was 10.0% (non gated plan) and 5.7% (gated plan),on average.
Conclusions: In this sample of patients, with small mobile lung lesions, respiratory gating enabled a reduction in the margins necessary for the PTV, thus
reducing the lung dose.
1279 poster
SETUP VARIATIONS DURING RADICAL CONFORMAL RADIOTHERAPY FOR OESOPHAGEAL CANCER
H. Ariyaratne1
1
R OYAL F REE H AMPSTEAD NHS T RUST, Academic Department ofRadiation Oncology, London, United Kingdom

Purpose:
1. To evaluate random and systematic setup errors during radical conformal radiotherapy for locally advanced oesophageal cancer.
2. To estimate the optimal target volume margin for planning of oesophageal volumes and compare with current guidelines.

2. Register the first CT on the radiotherapy planning CT;
3. Propagate the contours on the basis of computed vector field.
In this feasibility study, for validation purposes, we selected 5 cases inwhich lymph nodes were still positive after chemotherapy (ground truth location). A nuclear medicine physician contoured the volume of interest (VOI)
both on pre- and post-chemotherapy PET/CT. The two CT image sets werefirstly rigidly aligned and then registered through a B-Spline based image
registration algorithm. Pre-chemotherapy VOI were propagated on postchemotherapy CT according to the output vector field. The volume overlap
after rigid and non rigid alignment was used as validation metric.
Results: The percentage of volume intersection before non-rigid registration
was 26.2%, 59.0%, 0.0%, 100% and 16.5% for each patient. After contour
propagation it resulted 100%, 89.0%, 64%, 100% and 48.8%, respectively. In
each case, the proposed method led to a better result compared to rigid alignment that mimics the current clinical practice. As an example, Figure 1 shows
results for patient 2. The gray volume represents the actual position of lymph
nodes after chemotherapy. Black region represents the pre-chemotherapy
VOI, before and after deformable registration respectively.

Conclusions: This preliminary study shows the role of deformable registration for CTV localization in post-chemotherapy radiation treatment in HL
patients. A dosimetric investigation on CTV and OARs is ongoing, in order toevaluate the benefits of treatment volume optimization on surrounding organs
at risk.
1277 poster
REDUCING INTER-OBSERVER VARIATION OF BOOST-CTV
DELINEATION IN BREAST CONSERVING THERAPY USING A
PRE-OPERATIVE CT
L. Boersma1 , T. Janssen2 , P. Elkhuizen2 , P. Poortmans3 , M. van derSangen4 , A. Scholten5 , C. Hurkmans4 , C. van Vliet-Vroegindeweij2
1
MAASTRO C LINIC, GROW, U NIVERSITY M EDICAL C ENTRE M AAS TRICHT, Department of Radiation Oncology, Maastricht, Netherlands
2
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
3
D R . B ERNARD V ERBEETEN I NSTITUUT, Department of Radiation Oncology,
Tilburg, Netherlands
4
C ATHARINA Z IEKENHUIS, Department of Radiation Oncology, Eindhoven,
Netherlands
5
L EIDEN U NIVERSITY M EDICAL C ENTER, Department of Radiation
Oncology, Leiden, Netherlands
Purpose: Several studies have shown a large inter-observer variation in thedelineation of the boost-CTV in breast conserving therapy. The aim of thecurrent study was to investigate whether the availability of a pre-operative
CT scan (Preop-CT) decreases the inter-observer variation of the boost-CTV
delineation on the planning CT scan (Plan-CT).
Materials: Twenty-six breast cancer patients underwent a CT scan prior toand after breast conserving surgery. Five observers delineated the boostCTV according to guidelines defined by the observers prior to the study.
At first the boost-CTV was delineated on the Plan-CT without access to
the Preop-CT (boost-CTV-1). After submission, the observers obtained thePreop-CT on which they delineated the GTV. Subsequently, the Plan-CT was

Conclusions: We showed that inter-observer variation in the delineation of
the boost-CTV for breast conserving therapy can be substantially decreasedusing a Preop-CT, with a significant average decrease in COMd of 1.5mm.
In particular in those cases where there was consensus on the GTV, we saw
a marked improvement. We also found that the delineated boost-CTV wassmaller when the Preop-CT was available.
1278 poster
RESPIRATORY GATED RADIATION THERAPY: A DOSIMETRICANALYSIS
R. Righetto1 , M. Valenti1 , G. Mantello2 , M. Cardinali2 , S. Maggi1

Materials: The study sample population consisted of 12 patients treated withradical courses of radiotherapy with concomitant chemotherapy for locally advanced carcinoma of the oesophagus between April 2007 and April 2010. All
patients were treated on an Elekta radiotherapy unit using a conformal technique after CT planning. Standard positioning and immobilization techniques
were used. Kilovoltage verification images were obtained using the onboard
imager during the first 3 fractions of treatment and weekly thereafter, as aminimum requirement. A total of 114 KV verification images were available
for analysis. The Pinnacle system was used for fusion and comparison of images with the digitally reconstructed radiographs from the planning images,
and appropriate correction was applied if setup was outside predetermined
tolerances..
Results: The population random inter-fraction error was 5.5 mm in the
supero-inferior (SI), 2.7 mm in the left-right (LR) and 2.2 mm in the anteroposterior (AP) direction. The systematic setup error (weighted by number ofimages) was 3.3 mm in the SI, 1.4 mm in the LR and 1.4 mm in the AP direction. The Van Herk formula: Margin = (2.5 x systematic error) + (0.7 x random
error) was used to calculate the clinical target volume (CTV)-planning target
volume (PTV) margin. Using this formula, margins of 12.1 mm in the SI, 5.4
mm in the LR, and 5.1 mm in the AP direction were obtained.
Conclusions: There is significant setup variation in the superior-inferior direction during radiotherapy of oesophageal cancer. This would require a CTVPTV margin in the vertical direction larger than is recommended in contemporary radiotherapy trials. Individual radiotherapy centres should audit theirsetup errors to ensure that adequate margins are used during radiotherapyof the oesophagus.
1280 poster
THE DAILY ANALYSIS OF PROSTATE ROTATION
D. Grabec1 , B. Kragelj2
1
I NSTITUTE OF O NCOLOGY L JUBLJANA, Radiophysics Unit, Ljubljana,
Slovenia
2
I NSTITUTE OF O NCOLOGY L JUBLJANA, Radiotherapy, Ljubljana, Slovenia

1

A ZIENDA O SPEDALIERO U NIVERSITARIA O SPEDALI R IUNITI U MBERTO I G. M. L ANCISI - G. S ALESI, Department of Medical Physics and Radiation
Safety, Ancona, Italy
2
A ZIENDA O SPEDALIERO U NIVERSITARIA O SPEDALI R IUNITI U MBERTO I G. M. L ANCISI - G. S ALESI, Department of Radiation Oncology, Ancona,
Italy

Purpose: This study aims to evaluate the effectiveness of respiratory gatedradiation therapy (RGRT) in reducing the planning target volume (PTV) andin minimizing organ at risk dose.
Materials: Two different three-dimensional conformal radiation therapy(3DCRT) plans were generated for 8 pre-selected patients with non-smallcell lung cancer or lung metastases. Two different PTVs were considered (a)PTVnogating derived from an internal target volume (ITV) encompassing all
3D tumor mobility and (b) PTVgating derived from an ITV incorporating tumor
mobility observed in a gating window centered at end of inspiration. For the
purpose of this study 60Gy were prescribed to the isocenter placed at thecenter of gross target volume (GTV).
Results: The average free-breathing tumor motion was 16±9mm,
11±10mm and 6±2mm respectively in the superior-inferior (SI), anteriorposterior (AP) and latero-lateral (LL) directions. With respiratory gating the
average tumor motion reduced to 6±1mm 5±1mm 5±1mm, respectively,
along SI, AP and LL directions (duty cycles ranging from 20 to 35%). GTVs

Purpose: In radiotherapy of prostate cancer the precise definition of safetymargin around prostate is very important, since it allows optimal OAR sparing
at desired dose to the PTV. The safety margin due to the day by day prostatemotion is reduced with the usage of the golden markers. After the prostatetranslation is subtracted, the prostate rotation is still present. We are presenting the day by day prostate rotation analysis during the radiotherapy course,
and the corresponding estimation of the safety margins around the prostate.
When necessary, the rotation analysis can lead to the adaptive prostate planning.
Materials: Prior to the CT acquisition for the treatment planning three golden
markers are implanted in the patient’s prostate to assure the precise daily
prostate position. During the planning procedure one of the markers is chosen to be the in the isocentre (IC). The marker in the IC is named O. The
daily treatment patient position is corrected so the marker O is positioned in
the IC, also with help of the other two markers (A and B). The positioning of O
in the IC is done with the finite precision that leads to the translational safetymargins. The vector analysis OA and OB shows that the plane defined withthe three markers (AOB) rotates and deforms only slightly or not at all. Therefore also the rotational safety margins should be considered. The measure ofrotation is the direction of the cross product OA B = n, while the measure of
deformation is the norm of n. The reference condition is defined with planning
CT (O0, A0, B0, n0). The positions (O, A, B) of the markers at each irradiation

S 478I MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATIONI MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATION

course are measured from the two perpendicular EPI images of the treatedfraction (obtained at gantry 0◦ and 270◦ ). When the norm of n is almost
unchanged, we can neglect the prostate deformation, and only consider rotation around O. The rotation matrix M describes the prostate rotation: n = M
n0.The characteristic points of prostate (ri0 ) are chosen at the boundary of
the prostate at different layers at planning CT. The treatment position of therepresentative points of rotated prostate is calculated: ri = M ri0. So the setof treated positions of the rotated prostate (that cannot be revealed from the
EPI images) is defined.
Results: The set of positions of the ri reveals the spread of the characteristic
point position due to the prostate rotation between subsequent treatments.
The spread of orthogonal projections of the ri on x y and z axes is the measure for rotational safety margins in the directions x, y and z at the ri. The
presented method reveals the anisotropic rotational safety margins that differ
from apex to base of the prostate, from left to right etc.

The working of each specialized image processing application is then definedin a short script. The framework itself processes these scripts, creates thenecessary connections between data and/or viewers and handles user-input.
A novelty in this approach is the use of data channels (array of scans). In theabove-mentioned example, there will be channels named CT, PET, DOSE and
CBCT. There is no limit on the number of objects created other than available
memory. For specialized tasks such as contouring, masking or registration,
toolbars can be activated by defining their corresponding script objects. The
aim of the design is to find an optimum between flexibility and automation,with straightforward extendibility. The running state of the program can besaved at any moment as a new script, in order to be loaded later on and tocontinue running as normal.
Results: The framework is ready for its first applications. Two examples areshown in Figure 1. On the left a volume contouring application is shown,while on the right a 3D image registration application is depicted. On topof the running program images the corresponding script are shown. These
particular applications require only 16 and 19 scripting lines, respectively, tomake them fully functional. Planned applications include multi-modality target
volume definition, image guidance, dose accumulation, and pharmacokinetic
analysis.

Purpose: Deformable image registration, such as the intensity based BSpline Registration Method (BSRM), can help to track changes in shape andposition of anatomical structures obtained during the course of radiotherapy.
Such a registration is essential for dose accumulation in adaptive radiotherapy. The aim of this work is to evaluate the accuracy of the restored voxel
displacements of the BSRM in the head and neck (H&N) area. In particular
the effects on the registration result of parameter settings of the used algorithm, image contrast, and image mottle were studied.
Materials: Sixty CT images in the H&N area of a patient and of a synthetic
H&N phantom were utilized. The phantom contained spherical and ellipticalstructures simulating a tumour and several H&N organs. From the patient andthe phantom set, additional CT sets were constructed by imposing Gaussian
shaped deformations up to 20 mm. The phantom set was further modifiedby 1) addition of mottle of 1 up to 200 HU (1SD) and 2) addition of contrast
discs, simulating structures of various densities between -375 and 375 HU.
The BSRM of the Insight Toolkit 1 combined with Elastix 2 was used to register the various deformed patient and phantom CT sets back to their original,
undeformed set. The effect of the number of iterations and the B-Spline grid
spacing on the registration was investigated. Displacement vectors calculated in the deformable registration were compared with the imposed (known)
deformations. Average and maximal Residual Voxel Displacements (RVD)
in a volume of interest (e.g. parotid gland) were calculated and used as ameasure for the (Local) positional accuracy (LRVD).
Results: As a result of BSRMthe average LRVD decreased from 12 mm toless than 1 mm, and the maximal LRVD from 20 mm to 3 mm for about 100
iterations. The best result for the imposed 20 mm deformations was found fora B-spline gridsize of 15 mm. With increased mottle variation for the phantom
up to 50 HU (1SD), the LRVD remained < 1.0 mm. To obtain LRVD values
between 1.0 and 1.5 mm for mottle variations of 100 and 200 HU (1SD), 6
times more iterations were needed. Similarly, for low and zero contrast of thediscs, 2.5 times more iterations were needed to obtain average LRVD values< 1.5 mm. An average tracking accuracy after registration of better than 1.0
mm for parotid gland was found in this study. In some areas, however, LRVD
values of 3-4 mm were observed.
Conclusions: We presented a method to evaluate the accuracy of a deformable image registration application. The BSRM seems to be suitable forstructures like the parotid and submandibular glands in the H&N region. Careful tuning of parameter values like B-spline grid size and number of iterations
is important to obtain an average accuracy of about 1-2 mm in acceptablecomputation time.
References: 1. ITK: www.itk.org 2. Elastix: www.isi.uu.nl/Elastix
1283 poster
ACCURACY OF DEFORMABLE IMAGE REGISTRATION FOR
CONTOUR PROPAGATION IN ADAPTIVE LUNG RADIOTHERAPY
N. Hardcastle1 , W. van Elmpt2 , M. Oechsner3 , M. Guckenberger3 , D. De
Ruysscher2 , K. Bzdusek4 , W. Tomé11U NIVERSITY OF W ISCONSIN S CHOOL OF M EDICINE AND P UBLIC H EALTH,
Human Oncology, Madison, USA
2
MAASTRO C LINIC, Maastricht, Netherlands
3
U NIVERSITY H OSPITAL W UERZBURG, Radiation Oncology, Wuerzburg,
Germany
4
P HILIPS H EALTHCARE, Fitchburg, WI, USA

Conclusions: The calculated anisotropic rotational safety margins combinedwith the translational safety margins leads to the overall safety margins. With
the adaptive planning after daily prostate rotation analysis, we can apply
anisotropic safety margins that vary around prostate. Our irradiation schemeof radical prostate irradiation is PTV1 (prostate & nodes) followed with PTV2
prostate and seminal vesicles PTV3 prostate alone (D Grabec, B Kragelj, Radiol Oncol 2009; 43: 56-64). During the PTV1 irradiation the precise analysis
of prostate rotation is performed and applied for construction of PTV2 andPTV3. This approach leads to optimal OAR sparing.

Image registration, segmentation
algorithms and delineation
1281 poster
A NEW MANY-MODALITY VISUALIZATION AND REGISTRATIONPACKAGE FOR RADIOTHERAPY RESEARCH
H. van Piggelen1 , J. Duppen1 , M. van Herk1
1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands

Purpose: In radiotherapy research, structured and intuitive applications areindispensable to efficiently process the large amounts of image data being
collected. For instance, our patients in FDG-PET based escalation studies
have a baseline PET-CT, a dose plan, multiple CBCT scans acquired during
treatment and one or more follow up PET-CT examinations. In such a case,it may be required to correlate PET response with the estimated delivered
dose taking patient deformations into account. Rather than creating a specific application for this purpose, we are developing a new general-purpose
framework to serve as a basis for these kinds of applications, and other imaging research in radiotherapy.
Materials: The key to the new framework is the definition of a limited setof independent high level objects such as scans, viewers, and deformableregistration tools that are controlled and connected by a scripting language.

Figure 1. Two example applications built with simple scripts (overlaid). Above,a volume contouring application is depicted, while below, a 3D image registration application is shown. The scripts incorporate data flow, linked viewer
management and tools.
Conclusions: The framework and task-specific scripting language provide
excellent possibilities to quickly develop specialized analysis applications.
Since for all these applications there is only one baseline framework, development, maintenance and extension become less complex and less timeconsuming.
1282 poster
ACCURACY OF B-SPLINE BASED DEFORMABLE IMAGE REGISTRATION IN THE HEAD AND NECK REGION.
H. Meertens1 , C. Brouwer1 , A. van ’t Veld1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Radiation Oncology, Groningen, Netherlands

Purpose: Anatomical changes are often observed during radiotherapy treatment of lung cancer. Both normal tissues and tumor volumes can deform overtime. Obtaining volumetric images during treatment fractions allows trackingof any anatomical changes for adaptive protocols. This approach howeverrequires each volumetric image to be re-contoured. Currently, re-contouringof images during a radiotherapy course can be very time-intensive. Automatic
propagation of target and OAR contours between two image sets is thus an
attractive approach to reducing adaptive radiotherapy resource requirements.
The aim of this study was to evaluate two deformable image registration (DIR)
algorithms for the purpose of propagating contours from pre-treatment to midtreatment CT scans.
Materials: Pre-treatment and mid-treatment kVCT scans were obtained for
15 patients. The primary tumor (GTV), nodal tumor (GTV-nodes), lungs,
esophagus and spinal cord were delineated by a physician on each of the preand mid-treatment scans. DIR was performed by warping the pre-treatment
to the mid-treatment scans and applying the deformation map to the pretreatment scan ROIs to obtain ROIs on the mid-treatment scan. Two DIR
algorithms were used Demons (Thirion) and Salient Feature Based Registration (SFBR), as implemented in a research version of the Pinnacle RTPs
(v9.1, Philips Medical Systems, Fitchburg, WI). The DIR-propagated ROIs
were compared with the physician-drawn ROIs on the mid-treatment scanusing the Dice score and mean of the slicewise Hausdorff distance . The
difference in the Centre of Mass (COM) position of the GTVs was also measured.
Results: The average metric scores for each of the five ROIs are shown in
Figure 1. The DICE scores for normal structures were greater than for GTV
volumes. The mean Dice score was greater for SFBR than for Demons forall organs with the exception of right lung. The average Hausdorff distance
was lower with SFBR with all ROIs with the exception of the right lung. The

S 479

average COM difference for the GTV-tumor was 0.42 cm and 0.36 cm and
GTV-nodes was 0.40 cm and 0.35 cm for demons and SFBR respectively.

Figure 1: Dice score (top row) and mean DTA (cm) (bottom row) for the fivestructures investigated. The black circle is the mean, the grey bar is ± 1 SD
and the black horizontal bars are the minimum and maximum values.
Conclusions: Two DIR algorithms were successfully used to automatically
propagate both normal tissue and target volumes in repeat lung scans. Reasonably good agreement with physician drawn contours was observed fornormal tissues. DIR-propagated nodal contours were not as accurate mostprobably due to less soft tissue contrast for these structures.
1284 poster
AUTOMATED 2D/3D REGISTRATION FOR LUNG BRACHYTHERAPY
P. Zvonarev1 , T. Farrell12 , R. Hunter2 , J. Hayward2 , M. Wierzbicki2 , R. Sur3M C M ASTER U NIVERSITY, Medical Physics Applied Radiation Sciences,
Hamilton, Canada
2
J URAVINSKI C ANCER C ENTRE, Medical Physics, Hamilton, Ontario,
Canada3
J URAVINSKI C ANCER C ENTRE, Oncology, Hamilton, Ontario, Canada

1

Purpose: High dose rate brachytherapy is an effective modality of treatment
for obstructive lung cancer. For treatment planning, orthogonal X-ray images
are used to reconstruct the treatment catheters. However, the poor soft tissue
contrast of X-ray images does not allow visualization of the tumor or organs
at risk. Diagnostic CT images are available for each patient prior to treatment;
however these images cannot be directly fused with the orthogonal x-rays due
to differences in patient positioning. To account for this, a 2D/3D registration
algorithm was developed to register the orthogonal images to the CT volume,
thereby allowing for reconstruction of the treatment catheters in the CT data
set.
Materials: An image-based, rigid body registration algorithm was developed.
The best-neighbour search optimization was smoothed by parabolic interpolation. Image similarity was quantified using a combination of normalized
mutual information (NMI) and the sum of intensity differences. Evaluation of
the algorithm was performed using an anthropomorphic thorax phantom. Twonarrow channels were drilled in the phantom allowing for treatment catheters
to be inserted into the lungs. The phantom was placed in a custom bodymould to achieve reproducible positioning.CT images of the phantom wereacquired with and without the inserted treatment catheters (CT+, CT-). Orthogonal X-ray images were collected with the catheters in place and withthe phantom shifted and rotated in 3D for eight unique positions. The position
variation range was ±50 mm and ±15◦ for translations and rotations respectively. ECG leads were attached to the phantom at their normal anatomical
locations to mimic an actual lung treatment procedure. The orthogonal images were registered with the CT- data using the registration algorithm. The
catheter coordinates from the CT+ data and the X-ray images were digitizedusing BrachyVision software.
Results: The coordinates from the orthogonal pair reconstruction were transformed and were fused into the CT+ data. The transformed data were compared with the positions directly digitized in the CT+ images. Registration
error was quantified by computing the distance between the fused and true
catheter positions and varied from 0.5 mm to 2.5 mm for both catheters ineight different data sets. The mean error was 1.9 mm.
Conclusions: The proposed registration algorithm showed robustness tovarious degrees of initial displacement and to external objects introduced
during orthogonal image acquisition. The registration error was acceptablefor clinical applications.This work was supported by Varian Research Grant#07-583.

S 480I MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATIONI MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATION

1285 poster

1288 poster

DEFORMABLE IMAGE REGISTRATION FOR CONTOUR PROPAGATION FROM CT TO CBCT IN RADIOTHERAPY OF PROSTATECANCER
M. Thor1 , J. Petersen1 , L. Bentzen2 , M. Høyer2 , L. P. Muren1
1
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark

GPU BASED PARALLELISATION OF DEFORMABLE REGISTRATIONFOR DYNAMIC ADAPTATIONS IN RADIATION THERAPY
K. Giske1 , E. M. Stoiber12 , R. Bendl13
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
U NIV.
K LINIKUM H EIDELBERG, Department of Radiation Oncology,
Heidelberg, Germany
3
U NIVERSITY OF H EILBRONN, Department of Medical Informatics, Heilbronn, Germany

Purpose: Organ motion occurring during the course of radiotherapy of thepelvic region leads to uncertainties in the doses delivered to both the tumourand organs at risk. Motion patterns involve both volume and shape changes,
calling for deformable image registration (DIR), in particular when aiming fordose accumulation and adaptation. In this study, we tested the performanceof a commercial DIR application for contour propagation from the treatment
planning CT (pCT) to repeat cone-beam CTs (CBCTs) for a set of prostatecancer patients.
Materials: The prostate (CTVp), rectum and bladder were delineated in thepCT and in six to eight repeat CBCTs for each of five previously treated patients. The pCT contours were propagated onto the corresponding CBCTs
using the Multi-modality Image Registration and Segmentation (MIRS) application (MIRS v.1.0, Varian Medical Systems, Palo Alto, CA, USA), resulting in
36 registrations. Prior to the DIR, a rigid registration was performed. The algorithm used for the DIR arises from a ’demons’ algorithm. The performanceof the DIR was examined quantitatively using the Dice similarity coefficient(DSC) and qualitatively as visual slice-by-slice four-scale scoring (good, acceptable, need of adjustment and poor) by a radiation oncologist grading thenumber of unacceptable deviations (shape and/or distance) relative to theanatomy.
Results: The average DSC (range) for the rigid registration over all scans andpatients was 0.77 (0.65-0.86) for CTVp, 0.71 (0.55-0.82) for rectum and 0.64
(0.33-0.87) for bladder. The corresponding DSC for the DIR was 0.80 (0.650.87), 0.77 (0.63-0.87) and 0.73 (0.34-0.91). The fraction of scans scoredas good and poor respectively was 6 and 38% for CTVp; 6 and 69% forrectum and 0 and 42% for bladder. Linking the qualitative scoring i.e. good,
acceptable, need of adjustment and poor with the DSC for the corresponding
scan yielded: 0.74, 0.81, 0.80 and 0.80 for CTVp, 0.83, 0.83, 0.85 and 0.76
for rectum and N/A (no bladder scored as good), 0.88, 0.67 and 0.64 forbladder.
Conclusions: DIR improved the performance of contour propagation fromCT to CBCTs as compared to using rigid registration only. Still, a large fraction of the propagated rectum and bladder contours were clinically unacceptable. The amount of scatter in the CBCTs was extensive and the usability of
CBCTs for dose accumulation and adaptation purposes is therefore likely to
be improved by reconstruction using scatter correction.
1286 poster
FINITE ELEMENT BASED DEFORMABLE REGISTRATION OF
RADIOTHERAPY PLANNING CT USING TIME OF TREATMENTOPTICAL SURFACE SCANS
G. Price1 , J. Parkhurst1 , P. Sharrock1 , G. Whitfield2 , C. Moore1
1
T HE C HRISTIE NHS F OUNDATION T RUST, North Western Medical Physics,
Manchester, United Kingdom
2
T HE U NIVERSITY OF M ANCHESTER, Academic Department of Radiation
Oncology, Manchester, United Kingdom
Purpose: The optical measurement of patient skin surfaces at the time oftreatment is becoming increasingly prevalent in image guided radiotherapy(Peng et al. DOI: 10.1118/1.3483783, Moore et al. DOI: 10.1016/S03603016(03)00079-8). It would be desirable to be able to use such data not justfor patient positioning, but to be able to make dosimetric predictions upon theirbasis. The foundation of any such method is the deformable registration ofpatient planning CT scans to the optical surfaces measured at each fraction.
Accumulated dose can then be calculated through summing that from eachfraction in the deformed voxels. In this study we describe a finite element
based deformable registration strategy implemented at our institute and show
how the optical surfaces may be incorporated as registration constraints. We
verify the accuracy of the resulting deformations using CBCT image volumes
acquired simultaneously with the optical surfaces.
Materials: The optical surfaces were captured using an in-house designed
and constructed Fourier profilometry system installed in a treatment room
after Moore et al. (DOI: 10.1016/S0360-3016(03)00079-8) and Price et al.
(DOI: 10.1088/0031-9155/54/21/005). The finite element deformable registration system is based around the Altair Hypermesh package described by
Brock et al. (DOI: 10.1118/1.1915012) with custom built Tcl/Tk interface andutilising C++ and IDL callable modules. The accuracy of the technique is assessed in a preliminary case study using data from 2 oesophageal IMRT patients. The deformed RTP regions of interest (ROIs) are compared with thosein CBCT image volumes captured concurrently with the optical surfaces using
a closest point metric.

Results: Comparison of the cone beam and deformed RTP ROIs shows
close agreement at the skin surface (<2mm disagreement in overlap regions).
Those ROIs further removed from the surface show less conformity, although
the small field of view of the CBCT volumes (limited due to dose constraints)
make a comprehensive comparison difficult owing to the incomplete nature of
the comparison ROIs.
Conclusions: We have demonstrated a methodology for incorporating patient skin surfaces into finite element based deformable registration strategies. The accuracy of the matches, evaluated in a 2 patient case study,shows excellent agreement close to the body outline, although the precision
decreases away from the surface. Such a result is not unexpected as there
is no guarantee that external and internal motion is well correlated. However,
the technique has shown that it has value, either used in addition to othermeasured registration constraints, or perhaps targeted to regions where internal and external movements are known to be closely related.
1287 poster
FULLY AUTOMATED MODEL POSITIONING FOR SHAPE-BASEDBONE SEGMENTATION
A. Fraenzle1 , R. Bendl1 2
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Division of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
U NIVERSITY OF H EILBRONN, Heilbronn, Germany
Purpose: Until now a quantitative analysis of the entire degree of disease incase of multiple myeloma is not possible, since a large amount of image datafrom multiple modalities makes a manual segmentation of all bone lesions
impossible. For the automation of the image analysis process an accuratesegmentation of the affected bone structures is needed as a first step, so thatthe modified bone can be compared to a healthy model. The segmentationof single bone structures is a challenging task. Whereas the segmentationof the skeleton in CT images can be managed easily by applying a simple
thresholding, the delineation of single bones needs a more sophisticated approach due to a poor contrast and partial volume effects in the joints. A model
based approach shall be used here. To provide a fully automated segmentation with shape models, a method for the shape model positioning that uses
an automatic segmentation of the bone marrow regions is presented.
Materials: Since bone marrow of the single bones can be much more easily
separated, these structures are used here for the initialization of the model
positioning. With the bone marrow regions the rough position and orientationof the bone can be determined. The bone marrow regions are found by applying a threshold to get a segmentation of the whole skeleton followed by aflood fill algorithm to fill the holes in the skeleton. The difference of the filled
skeleton and the skeleton with holes delivers the bone marrow regions. A
connected component analysis labels the single objects. Pattern recognition
is used to assign the found bone marrow object to bone structures, so that theright shape models can be applied. The bone marrow volume and different
position parameters are used as classification features. The centroids of thebone marrow objects are used for positioning of the according shape models. The orientation of the model is determined by a PCA of the bone marrow
object. The algorithm was tested on transversal CT images of leg bones.
Results: With a random forest classifier, the bone marrow objects can beclassified sufficiently into the bone structures. The first principal componentof a bone marrow object is sufficiently precise to orientate the shape modelof the bone.
Conclusions: It has been shown that the developed methods work sufficiently for the bone legs. The method can be transferred to other bone structures, like vertebrae, to get a fully automated segmentation of single skeletonbones.

Purpose: Highly conformal radiation therapy techniques enable a targetedtumour irradiation with minimal impact on nearby healthy tissue and organs
at risk. However, changes in anatomy of the patient during the treatment
course compromise the achievable accuracy. Adaptations of the patient position or of the plan itself can compensate for the occurring deviations. For
such adaptations the transformations describing these changes are needed.
The current anatomy is acquired during the treatment course with control images. The transformations between the images can be extracted using image
registration methods. To consider also local anatomical changes deformableimage registration is a prerequisite. However, only little time is available tocope with observed changes during the therapy. Existing registration methods
are presently too slow to fulfill this task. Parallelisable deformable registration
methods are needed to exploit the potential of parallel hardware architecturesto hasten such computations.
Materials: To accelerate the registration process, a novel highly parallelisable
similarity measure (SM) tailored for GPU execution is developed: Based on
the global probability density function of the intensity values of the image
pair a local SM is introduced to reduce the complexity of the optimization
problem. In combination with a fast modified 3D-ChainMail algorithm [1] forvector field completion, it creates a registration process, which provides ahigh density of extracted correspondences using the parallel architecture of
the GPU accessed through the CUDA API [2].
Results: Parallelisation of the algorithmic components designed for a perfectmatch for the used hardware leads to a significant speed-up of the registration
method without compromising the accuracy. Using standard GPU hardware(GeForce 8800 GTX) calculation times of approximately one to a few minutes
are needed to align a pair of images with standard resolution. The achieved
accuracy is comparable to other state-of-the-art intensity-based registration
methods.
Conclusions: In this project we developed and implemented a highly parallel deformable image registration method for execution on GPU hardware.
The resulting duration of computations in combination with the good accuracy of the results can enable the implementation of adaptive strategies
within the same treatment fraction. [1] Gibson, 3D ChainMail: a Fast Algorithm for Deforming Volumetric Objects, I3D’97[2] NVIDIA Programming
Guide, http://developer.nvidia.com/object/gpu_programming_guide.html
1289 poster
GPU-SUPPORTED IMPLEMENTATION OF CONJUGATE GRADIENTMETHOD FOR RANDOM-WALKER IMAGE SEGMENTATION
F. Dittmann1 , K. Giske1 , R. Bendl12
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Medical
Physics, Heidelberg, Germany
2
U NIVERSITY OF H EILBRONN, Department of Medical Informatics, Heilbronn, Germany
Purpose: In 2006 Leo Grady introduced an algorithm realising a randomwalker image segmentation (RWIS) [1]. With this easy to use graph-based
method several structures can simultaneously be segmented, even if the contrast between adjacent structures is poor. The main disadvantage of thisalgorithm is that it produces huge linear equation systems (LES) that are
time consuming to solve. This is especially problematic for 3D-segmentationof medical image data records. The purpose of this new implementation is
to significantly increase processing speed of the conjugate gradient method(CG) and consequently of the whole segmentation process. Therefore thepossibilities of parallelization via a GPU-supported implementation had to beanalysed and realised. Another aim is to make the algorithm applicable forlarge 3D image data records without introducing special hardware (HW ) requirements. To achieve this, an efficient memory management is indispensable.
Materials: The graph for the RWIS is represented by a Laplacian weighting
matrix. In this sparse matrix only some diagonals are populated with nonzeros. Exploiting this, one can achieve a compressed diagonal based storage
format. An additional array is introduced to minimize the effort of extracting
the LES-matrix from the weighting matrix, enabling powerful compression as
well as coalesced memory access. The latter is necessary for an efficient
GPU-implementation of the matrix-vector-multiplication for CG.To reduce thenumber of iterations of the CG, the Jacobi preconditioner is used. Prior tosegmentation, a clipping-box is automatically placed around the structures toreduce data load.
Results: In the C/C++ module presented here, all components suited for

S 481

parallelisation were identified and implemented to run parallel on the single
instruction, multiple data architecture of GPU hardware. In test segmentations the GPU-implementation was 10 to 18 times faster than the CPUimplementation. The application of the Jacobi preconditioner reduced thenumber of necessary iterations by 25-50% in comparison to CG without preconditioning. The segmentation of both lungs (2.4 million voxels inside theclipping-box) took less than 50s (in contrast to 516s using CPU only). A data
set with 9.4 million could be segmented on 512MB graphics memory HW.
Conclusions: The results of the accomplished test segmentations show thebenefit of GPU-support for CG and RWIS. Using an appropriate data structure for the weighting matrix an efficient and memory saving implementation was achieved, which in turn makes the algorithm usable for large scale
3D-segmentation. Future research could examine different mathematical approaches for fast solving of LES during RWIS, to enable real-time interactive
segmentations.
Grady, Leo: Random Walks for Image Segmentation; IEEE Trans. PatternAnal. Mach. Intel l. 28 (2006), nr. 11, p. 17681783
1290 poster
IMAGE REGISTRATION OF LUNG CT AND HYPERPOLARIZEDHELIUM-3 MRI VIA PROTON MRI FOR PATIENTS WITH NSCLC
R. Ireland1 , J. Swinscoe2 , M. Hatton2 , H. Marshall1 , S. Ajraoui1 , J.
Parra-Robles1 , J. Wild1
1
U NIVERSITY OF S HEFFIELD, Radiology, Sheffield, United Kingdom
2
U NIVERSITY OF S HEFFIELD, Clinical Oncology, Sheffield, United Kingdom
Purpose: NSCLC patients undergoing RT may benefit from functional lung
image evaluation provided by noble gas MRI such as helium-3 (3 He) [1]. Thisapproach requires a robust method of image registration to gold-standard
CT lung images. Preliminary work demonstrated the theoretical applicationof mutual information to provide an automatic registration of 3 He MRI to CT
when the ventilation images are acquired in the same imaging session as aproton (1 H) MRI [2]. However, a major limitation was that separate breathholds were required when acquiring the two sets of MR images. To alleviate
this problem, lung image acquisition of both 3 He MRI and 1 H MRI in the same
breath-hold has recently been achieved [3]. The aim of this study was to test
the feasibility of synchronous 1 H-3 He MRI acquisition in lung patients and toregister the MRI to treatment planning CT.
Materials: Before RT, 4 patients underwent MR imaging. 3 He gas was polarized on site and ventilation images were acquired during a single breath-holdof 1L 3 He / N2 mix. With patients in the treatment position (arms supported
upright), 3 He MRI was acquired on a 3T system fitted with a second RF amplifier using prototype transmitreceive (T-R) coils. During the same breath-hold,the coil was detuned during 1 H transmit and 1 H TR was performed with thescanner’s 1 H body coil, which itself was actively detuned during 3 He TR [3].
On the same day, RT planning CT was acquired using an inspiration breathhold technique to mimic the MRI breathing manoeuvre [4]. The desired 3 He
MRI to CT image registration was performed in two automatic steps. Firstly,
1
H MRI was rigidly registered to planning CT using mutual information. Secondly, as the 3 He and 1 H MRI are acquired in a single breath-hold the calculated transformation for 1 H MRI to CT was directly applicable to 3 He MRI.
Results:

The 4 patients tolerated the imaging procedure well and held their breath longenough for all sets of images to be acquired without any detrimental clinicaleffects. All ventilation images were successfully fused with RT planning CT.
The registration procedure is demonstrated in Fig 1. a) 3 He MRI (blue) and1
H MRI are inherently registered due to the single breath-hold acquisition
sequence. b) 1 H MRI (red) is registered to the planning CT (green). c) 3 He
MRI can be similarly registered to CT using the same transformation.
Conclusions: This work demonstrates the feasibility of synchronous
acquisition 3 He and 1 H lung MRI for NSCLC patients, and automatic
registration of the ventilation images to CT via mutual information of anintermediate 1 H MRI. The presented automatic method of registration may
be a useful supplementary tool for the planning and evaluation of lung cancer
radiotherapy and its side effects.
1. Ireland RH et al. Int J Radiat Oncol Biol Phys 68(1):273-281, 2007
2. Ireland et al. ESTRO Abstract 4225, 2008

S 482I MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATION

3. Wild JM et al. NMR Biomed (DOI: 10.1002/nbm.1565), 2010

I MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATION

Purpose: Evidence is accumulating that radiotherapy to the conserved breastis associated with an increased risk of heart disease ten or more years after
the radiotherapy was given and that this risk depends on the dose to heart.
Therefore it has become part of daily clinical practice in many centres to contour the heart and in some centres also the left ascending coronary artery(LAD). Dose to these structures is often minimized at the cost of poorer target
coverage. Well defined and robust planning constraints are therefore important in order to get the best compromise between maximizing target coverageand minimizing the dose to the heart. The aims of this study are to describe
the inter-observer variation in delineation of cardiac structures and the influence of this delineation uncertainty on the dose-volume metrics related to thedose plan.
Materials: The first part of the study has included ten patients selected randomly from patients receiving adjuvant radiotherapy to the conserved left
breast. So far, the heart and the LAD have been contoured by five different persons from centres in Denmark and the UK. The centres received theplanning CT-scans of the patients without any contours delineated and without any instructions on how to define and contour the heart and LAD. The
contours from the different observers were imported into Pinnacle where thedose from the treatment plan used was calculated with the Collapsed Conealgorithm.
Results: From visual inspection of the heart contours it became clear thatthe observers used different definitions of what to include in the outline of
the heart, especially regarding the superior boundary. However, the mean
heart dose was relatively constant between observers with a mean value of
1.83Gy and a coefficient of variation (CV) between observers with a meanof 5.2%. The maximum dose lies on a steep dose gradient and is sensitive
to differences in delineation, however little variation was present in this area
and the maximum dose had a mean of 39.5Gy and a mean CV of 6.9%. The
LAD is a small structure which can be difficult to visualise on a conventional
planning CT-scan without contrast, and it is positioned near a steep dose
gradient. Large variations between observers were seen in estimated doses(mean dose: 5.85Gy, CV 21% and maximum dose: 23.1Gy, CV 29%)

4. Ireland RH et al. Phys Med Biol 53(21):6055-6063, 2008

1291 poster
INTERACTIVE 3D EDITING OF PATIENT ANATOMY
L. Hibbard1
1
E LEKTA CMS, Research Department, Maryland Heights, USA
Purpose: An obstacle to adaptive radiotherapy is the lack of efficient tools
to review and edit the output of automated segmentation programs. This
abstract describes new interactive software technology that can efficiently resculpt 3D anatomy, integrating user drawn inputs from any combination of
the transverse/sagittal/coronal (T/S/C) views. Further, user edits in a small
number of T/S/C planes can produce accurate and smooth shape changes
over large regions of a structure surface.
Materials: Anatomy delineations obtained by computer segmentations orfrom other sources are first reconstructed as implicit surfaces. An implicit
surface is taken as the 0-th level set of an implicit function f (x,y,z)=k definedby a weighted sum of radial basis functions (RBFs) centered on constraint
points at x,y,z-locations on or close to the structure surface. Weights are obtained by factoring a linear system involving the constraints. Surface point
locations between the constraints are computed by interpolating the implicit
function. The resulting implicit surfaces are smooth, continuous, and can represent complex shapes. Surface shape changes are accomplished by altering the arrangement of the constraint points, recomputing the implicit function
weights, and recomputing a new mesh of surface points. New arrangementsof constraints are dictated by user-drawn alterations (edits) to projections of
the surface displayed in the 2D T/S/C views. The user may draw new partsof contours at intervals in the T/S/C planes over the existing surface, and the
new surface is interpolated smoothly between the user’s 2D planar inputs.
Extensive multithreading is used to speed up this computationally-expensive
program, including functions that compute multiple portions of a surface inparallel followed by exact stitching of the resulting meshes. This programis deployed in a development version of a commercial interactive contouring
program, CMS Focal 4D.
Results: Updating the displayed anatomy to reflect the most recent edits
typically takes ~3-5 seconds. Figure 1 shows an undersegmented bladder[1], interactively edited in a sagittal plane [2]. The recomputed bladder surface[3,4] integrated a combination of sagittal and transverse edits. This bladder’ssurface mesh had ~12,000 polygons.

S 483

1293 poster
NOVEL METHODOLOGY FOR VISUALIZATION AND ANALYSIS OF
4D FUNCTIONAL CT
C. Coolens1 , W. Wee2 , B. Driscoll3 , D. Jaffray4
1
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO,
Radiation Medicine Program; Department of Radiation Oncology, Toronto,
Canada2
U NIVERSITY OF TORONTO, Biomedical Engineering, Toronto, Canada
3
P RINCESS M ARGARET H OSPITAL, Radiation Medicine Program; Department of Radiation Physics, Toronto, Canada
4
P RINCESS M ARGARET H OSPITAL, Radiation Medicine Program; Department of Radiation Oncology, Toronto, Canada
Purpose: Quantitative functional imaging methods have become more prominent in radiotherapy for target definition and early response detection of treatment efficacy. The development of 4D perfusion CT requires more sophisticated methods of acquiring 3D functional parameter maps. This research
proposes a novel method for (a) segmenting vasculature and perfused tissue from 4D dynamic contrast-enhanced (DCE) CT scans containing otheranatomical structures, and (b) creating 3D functional parameter maps of perfused tissue for tracer kinetic analysis.
Materials: The segmentation method determines if a voxel represents perfused tissue by analyzing the voxel’s time-intensity curves. This is accomplished in three stages; preprocessing, 3D volume analysis, post-processing.
In preprocessing, the time-intensity curves for every voxel are obtained andidentifiable uptake-curve features are derived to characterize vasculaturefrom other anatomical structures. Filter thresholds are adjusted to differentiate voxels and eliminate time-points with significant motion. The 3D volume
analysis stage creates a volume of voxels that satisfy the filter thresholds.
Voxels are removed if they are outside the field of view or are not vasculature.
Post-processing then creates a finalized segmentation mask file that was visualized with Amira ®(Visage Imaging). Segmentation accuracy validation
was performed on a control flow phantom of known dimensions.
Results: The methodology was tested on 4D DCE-CT scans of a phantom
and data from 3 patients with metastatic brain tumors. The methodology’s
effectiveness in automatically segmenting contrast-enhanced volumes has
been shown qualitatively. In addition known phantom volumes were accurately segmented to within +/- 6%. It was possible to generate perfusion
characteristics and 3D parameter maps in all patients; this includes the maximum contrast enhancement, time-to-peak and maximal slope and the values
were in line with values derived using commercial perfusion software.

Conclusions: We have demonstrated a method to interactively edit 3D
anatomy shapes, on a software platform that provides fast updates in a familiar user interface. Ongoing work aims to incorporate image edge and texture information in constraint placement, to further increase the program’s
efficiency, and to determine useful guides for placing edit constraints.
1292 poster
MULTI-INSTITUTION VARIATION IN DOSE TO THE HEART FOR
BREAST CANCER PATIENTS DUE TO THE UNCERTAINTY IN
DELINEATION
E. L. Lorenzen1 2 , C. Taylor3 , M. Maraldo4 , M. M. Nielsen5 , D. O’Dwyer2 , M.
R. Andersen2 , I. R. Vogelius4 , S. Darby3 , M. Ewertz1 5 , C. Brink1 2
1
U NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark
2
O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
Denmark
3
U NIVERSITY OF OXFORD, Clinical Trial Service Unit, Oxford, United
Kingdom
4
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of Radiation
Oncology, Copenhagen, Denmark
5
O DENSE U NIVERSITY H OSPITAL, Department of Radiation Oncology,
Odense, Denmark

Conclusions: For the whole heart, delineation varies between observers
from different centers, but in the region near the treatment fields less variationis seen, and the inter-observer variation in dose is acceptable. For the LAD,
estimated doses are more sensitive to inter-observer variation in delineationand so dose estimates have to be used with more precaution. In studiesof dose-volume effects to the heart and in clinical trials using dose-volume
constraints, consistent methods of delineation need to be devised and implemented. The study is continuing including more patients and more observers
to refine the preliminary results presented here.

Conclusions: The proposed methodology has demonstrated its accuracy increating 3D segmentation volumes (of vasculature and perfused tissue) withperfusion characteristics. This is an important milestone towards achieving
an automatic, volumetric and quantitative functional imaging method.
1294 poster
PERFORMANCE EVALUATION OF THE ATLAS-BASED AUTOSEGMENTATION SOFTWARE (ABAS) FOR PROSTATE CANCER
M. Ayadi1 , R. Lynch2 , F. Lafay1 , P. Pommier1
1
2

C ENTRE L ÉON B ÉRARD, Lyon, France
A NDREW L OVE C ANCER C ENTRE, Radiation Oncology , Geelong, Australia

S 484I MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATIONI MAGE REGISTRATION , SEGMENTATION ALGORITHMS AND DELINEATION

Purpose: New therapy modalities such as dynamic therapy, IMRT or stereotactic RT require accurate delineation of clinical target volumes and organs
at risk in order to ensure high dose conformity provided by an inverse planning algorithm and to improve tumor control probability and to limit the normal tissue complication probability. The aims of the study were to evaluate
the performance of Atlas-based Auto-Segmentation (ABAS, Elekta CMS, St.
Louis, MO) in terms of autocontouring structures efficiency in prostate cancer
and to determine if the number of atlases increase the robustness of the auto
segmentation.
Materials: Ten patients treated for prostate cancer (T1-T3b) were included in
the study. Each patient underwent a CT scan of 1.5mm slice width. On eachCT data set, one radiation oncologist delineated, using the Focal software(CMS), the following "reference" contours for: prostate, seminal vesicles,
bladder, rectum and penile bulb. A consensus was reached for the above
structures after review by a second radiation oncologist and a diagnostic radiologist. Ten atlases were generated in ABAS using CT scans data sets fromthe consensus reached by the group. A reference atlas was selected since
the structures were easily delineated on the CT scan. For each patient theatlas was tested in three ways:- 1/ to the reference atlas; 2/ to the referenceatlas and second atlas using the simultaneous truth and performance levelevaluation (STAPLE) algorithm, 3/ and finally to all the atlases, including thereference atlas, using the STAPLE algorithm. We evaluated the structures
deformed by ABAS using the Dice Similarity Coefficient (DSC) calculated by
the Artiview software (AQUILAB). The autocontouring time was recorded andused as a comparison with the time taken by the clinicians to mark thesevolumes.
Results: Preliminary results for the five patients indicated that there was thefollowing variability in mean volume (standard deviation) for the bladder, rectum, penile bulb, prostate and seminal vesicles, respectively 111.7cc (43.8),
63.8cc (24.7), 1cc (0.6), 34.9cc (10.1), 13.7cc (7.6).The autocontouring timevaried from 1 minutes 32s to 7 minutes 7s. The bladder and prostate basedon the DSC appear to be quite well represented (mean of 0.82 and 0.68 respectively) but upon reviewing the images, comparing the deformed contours
and the reference contours, the interface between bladder and prostate was
not well delineated. For the seminal vesicles, the mean DSC was 0.462 consistent with the analysis of the images. The STAPLE algorithm seems not toimprove the delineation of the structures within the male pelvis.

or ’Poor’ (TRE>2.5mm). The correlation ratio SM was calculated along thesix cardinal axis of the RB transform space at intervals of 0.2mm. The shapeof the SM was characterised by seven different measures describing minimum SM, accuracy and distinctiveness of optimum. These measures wereused to train and test a Bayesian Network using K-fold cross validation. The
machine learning process was repeated using just 25 points; the ’found’ optimum and two points either side of the location of the ’found’ optimum on
the six cardinal axes of the RB transform.Three CBCT images and their reference CT image for each of six patients previously treated with intra-cranialradiotherapy were chosen for this study. The global optimum RB transformfor each image pair was located by applying random misalignments before IR
and calculating the average rigid body transform returned by the algorithm.
A measure of target registration error (TRE) was calculated for each registration from the residual RB transform. IRs were classified as ’Good’ (TRE
< 0.6mm), ’OK’ (0.6<TRE<2.5mm) or ’Poor’ (TRE>2.5mm). The correlation
ratio SM was calculated along the six cardinal axis of the RB transform spaceat intervals of 0.2mm. The shape of the SM was characterised by sevendifferent measures describing minimum SM, accuracy and distinctiveness of
optimum. These measures were used to train and test a Bayesian Network
using K-fold cross validation. To reduce the computation time, the machinelearning process was repeated using just 25 points; the ’found’ optimum andtwo points either side of the location of the ’found’ optimum on the six cardinalaxes of the RB transform.
Results: No single characteristic of the SM curves correlated well with TRE.
However, the Bayesian Network was able to correctly classify 84% of IRs
based on the detailed similarity metric profiles. No ’Poor’ IRs were classified
as ’Good’ and vice-versa. Almost identical results were achieved with the
25 point measures but one out of 449 IRs were classified as ’Good’ when
actually ’Poor’.
Conclusions: This demonstrates the potential for machine learning basedon the local shape of the SM hyper-surface to check likelihood of IR accuracy
using only a few calculations of the SM. Such methods could be used to reassure radiation technologists when auto-IR is successful and indicate whencloser scrutiny and manual adjustment of image alignment is required.
1296 poster

correlation = i=N −1i=0

i=N −1i=0

6ri (t) = Ai cos(T (i) − T̄ )(S(i) − S̄)(T (i) − T̄ )2

i=N −1i=0(S(i) − S̄)2π
t − φresp 
ni + riinit
Tresp

(3)
(4)

A Chest 3D model including lungs, ribs, sternum, and spine is constructedfrom exhalation CT images using binarization, mathematical morphology, andregion growing. In our approach, lung properties are assumed to be linear
elastic material. Governing equations for a lung deformation of a linear elastic material can be written as Eq. (1),(2). Rib kinematics is also simulated
based on a two-axis rotation model and its effect is incorporated into theboundary conditions of the lung deformation simulation. Diaphragm motion of
abdominal breathing is also considered to the boundary conditions using CT
images acquired during the inhalation and exhalation phases by calculating
coefficient correlation (Eq. (3)). The forced boundary condition is applied tocontour particles (Eq. (4)). A lung motion is then predicted using the particle
method. Since CT images are required for radiotherapy planning, we propose
a generation method for simulation-based quasi-4DCT (four-dimensional CT)
images, which are equivalent to actual ones, using CT images acquired during the inhalation and exhalation phases. The quasi-4DCT images are generated based on particle simulation results using the image warping technique.
Results: Simulation accuracy is validated by comparing the maximum displacements in the simulation and in the observed result between inhalationand exhalation CT images. Validation points are chosen from the bifurcationsof vessels and airways. Total displacements become smaller as the position approaches from the diaphragm to the lung apex. The observed andsimulation results indicate that the dominant factor is the diaphragm motion.
Moreover, AP motion is larger than LR motion. These results agree well withthe results of 4DCT kinetic analysis.
Conclusions:

QUASI-4DCT IMAGES BASED ON PHYSICS-BASED LUNG DEFORMATION SIMULATION
H. Ito1 , S. Koshizuka1 , R. Shino1 , A. Haga2 , T. Onoe2 , K. Nakagawa2
1
T HE U NIVERSITY OF TOKYO, Graduate School of Engineering, Tokyo,
Japan
2
T HE U NIVERSITY OF TOKYO H OSPITAL, Department of Radiology, Tokyo,
Japan

Conclusions: This is the first study of autocontouring with ABAS for prostatecancer.The algorithm with further development could be a useful tool in theclinical setting, however currently significant modifications are required. The
plan is to assess ABAS using MRI images for the planning of prostate cancer.

Purpose: It is important to estimate quantitatively lung motion during thebreathing cycle for the purpose of more accurate irradiation. Radiation exposure to normal tissues can be reduced if the interfractional-motion of lungs
is accurately predicted by physics simulation based on patient-specific CT
images. We propose a lung deformation simulation technique using a particle method. We also develop a construction method of quasi-4DCT images,
which are equivalent to real-4DCT ones, from the biomechanical simulation
result for applying 4D radiotherapy treatment planning. Finally, simulation accuracy is validated quantitatively between inhalation and exhalation.
Materials:

1297 poster

1295 poster

SEGMENTATION USING SYMMETRY DEVIATION
C. Hollensen123 , L. Højgaard2 , L. Specht1 , R. Larsen3
1
C OPENHAGEN U NIVERSITY H OSPITAL – R IGSHOSPITALET, Department ofRadiation Oncology, Copenhagen, Denmark2
C OPENHAGEN U NIVERSITY H OSPITAL - R IGSHOSPITALET, Department ofClinical Physiology and Nuclear Medicine and PET, Copenhagen, Denmark
3
T ECHNICAL U NIVERSITY OF D ENMARK, Department of Informatics
Mathematical Modelling, Kgs. Lyngby, Denmark

PREDICTING IMAGE REGISTRATION QUALITY FROM THE SHAPE
OF THE SIMILARITY METRIC: POTENTIAL FOR MACHINE LEARNING APPROACHES
J. Sykes1 , D. Brettle1 , D. Magee2 , D. I. Thwaites1
1

S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Department of Medical Physics Engineering, Leeds, United
Kingdom
2
U NIVERSITY OF L EEDS, Computer Science, Leeds, United Kingdom
Purpose: Typically, image guided radiotherapy relies on rigid body (RB) image registration (IR) between a reference and localisation image. AutomatedIR algorithms based on iterative optimisation of a similarity metric (SM) between two images are used extensively and improve the efficiency and accuracy of this process. Occasionally these algorithms do not locate the global
optimum of the SM which, if undetected, could lead to a geometric treatment
error. This feasibility study uses machine learning to predict the likelihoodthat the location of the ’found’ optimum was acceptably close to the global
optimum based on measures of the SM hyper-surface.
Materials: Three CBCT images and their reference CT image for each of six
patients previously treated with intra-cranial radiotherapy were chosen for thisstudy. The global optimum RB transform for each image pair was located byapplying random misalignments before IR and calculating the average rigid
body transform returned by the algorithm. A measure of target registration
error (TRE) was calculated for each registration from the residual RB transform. IRs were classified as ’Good’ (TRE < 0.6mm), ’OK’ (0.6<TRE<2.5mm)

A particle generation method from CT images for lung and ribcage has beendeveloped. Lung deformation is simulated using the particle method. A construction method of quasi-4DCT equivalent to real-4DCT is developed using
image warping technique. Simulation accuracy between inhalation and exhalation is validated quantitatively. In the future plans, we will take into accountthe motion of the body surface and the effect of pleura sliding. Moreover, weare going to apply quasi-4DCT to 4D radiotherapy treatment planning.

ρ∂rα ∂t = vα

(1)

Dvα
= ∂∂xβ (λγγ δαβ + 2µαβ )Dt(2)Purpose: The manual delineation of gross tumour volume(GTV) for radiation therapy for head and neck cancer patients relies in some degree ofpathological deviation from normal anatomical symmetry. The purpose ofthis study is to introduce a novel method for 3-dimensional determination of
GTV and evaluate the method. The method uses deformable registration on
computed tomography(CT) to find anatomical symmetry deviations of Head& Neck squamous cell carcinoma and combining it with positron emission
tomography (PET) images. The method allows the use anatomical and symmetrical information of CT scans to improve automatic delineations.
Materials: PET/CT scans from 30 patients were used for this study, 20 without cancer in hypopharyngeal volume and 10 with hypharyngeal carcinoma.
An head and neck atlas was created from the 20 normal patients. The atlas
was created using affine and non-rigid registration of the CT-scans into a single atlas. Afterwards the standard deviation of anatomical symmetry for the
20 normal patients was evaluated using non-rigid registration and registeredonto the atlas to create an atlas for normal anatomical symmetry deviation.
The same non-rigid registration was used on the 10 hypopharyngeal cancer
patients to find anatomical symmetry and evaluate it against the standard

S 485

deviation of the normal patients to locate pathologic volumes. Combining
the information with an absolute PET threshold of 3 Standard uptake value(SUV) a volume was automatically delineated. The overlap of automated segmentations on manual contours was evaluated using concordance index andsensitivity for the hypopharyngeal patients. The resulting concordance index
and sensitivity was compared with the result of using a threshold of 3 SUV
using a paired t-test.
Results: The anatomical and symmetrical atlas was constructed. The standard deviation of the anatomical symmetry, seen in figure for one patientalong CT and PET, was extracted for normal patients and compared with thedeviation from cancer patients giving a new way of determining cancer pathology location. Using the novel method an overlap concordance index andsensitivity of respectively 0.43±0.15 and 0.56±0.18 was acquired. It wascompared to the concordance index of segmentation using absolute threshold of 3 SUV giving respectively 0.41±0.16 and 0.51±0.19 for concordanceindex and sensitivity yielding p-values of 0.33 and 0.01 for a paired t-test respectively.

S 486

IMRT: C LINICAL IMPLEMENTATIONIMRT: C LINICAL IMPLEMENTATION
Conclusions: It is possible to use non-rigid registration to extract anatomical
symmetry information from CT scans and use it for segmentation of cancer
volumes. The methods should be further investigated to discover their fullpotential.
1298 poster
STANDARDIZING NAMING CONVENTIONS IN RADIATION THERAPY
L. Santanam1 , S. Mutic1 , S. Brame1 , C. Hurkmans2 , C. van VlietVroegindewij3 , W. Straube4 , J. Galvin5 , P. Tripuraneni6 , J. Michalski1 , T. J.
Fitzgerald7 , W. Bosch8
1
WASHINGTON U NIVERSITY M EDICAL C ENTER, Department of Radiation
Oncology, St. Louis, USA
2
C ATHARINA Z IEKENHUIS, Department for Radiooncology and Radiotherapy,
Eindhoven, Netherlands
3
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Department of Radiation Oncology, Amsterdam, Netherlands
4
WASHINGTON U NIVERSITY M EDICAL C ENTER, St. Louis, USA
5
T HOMAS J EFFERSON U NIVERSITY, Department of Medical Physics andRadiation Safety, Philadelphia, USA
6
S CRIPPS C LINIC, La Jolla, CA, USA
7
Q UALITY A SSURANCE R EVIEW C ENTER, Administration , Providence, USA
8
WASHINGTON U NIVERSITY M EDICAL C ENTER, Radiation Oncology Section Quantitative Magnetic Resonance Imaging, St. Louis, USA
Purpose: The aim here is to report on the development of a standardized
target and organ at risk naming convention for use in Radiation Therapy andto present the nomenclature for structure naming for inter-institutional data
sharing, clinical trial repositories, integrated multi-institutional collaborative
databases and quality control centers. This taxonomy should also enableimproved plan benchmarking between clinical institutions and vendors andfacilitation of automated treatment plan quality control.
Materials: The Advanced Technology Consortium (ATC), Washington University in St.Louis, Radiation Therapy Oncology Group (RTOG), Dutch Radiation Oncology Society (NVRO) and the Clinical Trials RT QA Harmonization Group collaborated in creating this new naming convention. The ATC
structure naming schema, available on the ATC website and the ICRU guidelines have been used to create standardized nomenclature for target volumes(CTV, ITV, PTV etc.), organs at risk (OAR), and planning organ at risk volumes(PRVs) in radiation therapy. The nomenclature also includes rules for specifying laterality and margins for various structures. The naming rules distinguishtumor and nodal PTVs, with correspondence to their respective tumor/nodal
CTVs. The naming convention provides rules for basic structure naming, as
well as an option for more detailed names. There is also a correspondence
between the base names and the detailed names which can be identified bystructure mapping. Names of non-standard structures used mainly for plan
optimization or evaluation (rings, islands of dose avoidance, islands where
additional dose is needed (dose painting)) are identified separately.
Results: In addition to its use in 12 ongoing RTOG advanced technology clinical trial protocols, a pilot version of this naming convention has been evaluated using 100 patient data sets with varying treatment sites. All structures inthese data sets were satisfactorily identified using this nomenclature.
Conclusions: Use of standardizing naming conventions is important to facilitate comparison of contouring and dosimetry across patient datasets. The
guidelines presented here will facilitate international acceptance across awide range of efforts, including ATC, RTOG, EORTC, ROI, NVRO, IHE-RO,
and DICOM. The guidelines can improve inter-institutional data sharing andare easy to adopt by individual clinics and vendors. Consistent nomenclature
should also facilitate the development of more automated or standardized
clinical workflows.

IMRT: Clinical implementation
1299 poster
A NATIONAL PHASE III TRIAL OF PELVIC LYMPH NODE (LN)
IMRT IN PROSTATE CANCER (PIVOTAL): A COMPARISON OF LNOUTLINING METHODS
V. Harris1 2 , C. South2 , C. Cruickshank3 , D. Dearnaley1 2
1
I NSTITUTE OF C ANCER R ESEARCH, Academic Radiotherapy, Sutton,
United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Sutton, United Kingdom
3
I NSTITUTE OF C ANCER R ESEARCH, Section of Clinical Trials, Sutton,
United Kingdom
Purpose: Since 2000 guidelines for defining pelvic lymph node (LN) clinicaltarget volume (CTV) have been in use at The Royal Marsden Hospital (RMH)
for use in prostate/ pelvic LN IMRT and were the basis of phase I and phase
II safety data for this technique. However, these guidelines rely upon thecontouring experience of a few individuals and may be difficult to reproduce
in a multi-centre setting. We compared the resulting pelvic LN CTV volumeof the RMH technique with the RTOG method of defining pelvic LNs, in orderto determine which technique would be used within a national randomised
controlled trial (PIVOTAL).
Materials: The pelvic lymph node CTVs of 7 patients who had previously
received IMRT to prostate and pelvic LN were reviewed to ensure their contoured pelvic LN volumes precisely followed the RMH guidelines. For each ofthese patients a new pelvic LN CTV was created by following the vascular expansion technique of the RTOG[1], whilst blinded to the RMH CTV. The CTV
volume for each patient using each technique was obtained. The mean volume for each technique was calculated and compared using a paired t-test.
Results:

S 487

of significant hot and cold spots), clinical significance of the variance, andoptimisation required were recorded.
Results: 51 patients were treated with a forward planned 7 field IMRT technique during the audit period. 18 (35%) patients under went a second planning CT to assess the need for optimisation of the radiotherapy plan due tocontour change. 7 patients required no change to the radiotherapy plan, 3plans under went minor adjustment with a change in monitor units and 8 required a new immobilization shell and a subsequent replan.
Conclusions: Our current adaptive radiotherapy protocol for forward planned
7 field head and neck IMRT results in unnecessary CT scans for patients anda significant increase in treatment planning time and subsequent quality assurance of any reoptimised plans. Changing the adaptive policy to only rescanning those patients who require a second immobilisation shell and those
who have lost >10kg in weight would be sufficient to prevent significant hot orcold spots in the irradiated volume during radiotherapy.
1301 poster

A concensus meeting of ’PIVOTAL’ trialists reviewed these results with thefollowing observations:
1. Both methods cover the majority of relevant LN areas, but flexibility
is needed to include ’small white dots’ (assumed to be LNs) in the
RTOG method (the small white dots are routinely included in the RMH
method)2. For both methods:
1. Pre-sacral region should cover S1-S3 inclusive and is a 12mm strip
anterior to the sacrum
2. Superior extent of LN CTV is the mid point of the L5/S1 interspace
3. Inferior extent of LN CTV is 1cm above pubic symphysis
4. Obturator region is 18mm wide strip measured from inner surface ofbony pelvic side wall
5. The use of a bowel planning organ at risk (PRV) margin to reduce
excess overlap between PTV and bowel should be assessed
6. Additionally, use of the RTOG method requires:
7. ’Carve out’ of bladder, bone, bowel and muscle
8. IV contrast to aid vascular outlining
9. Vascular expansion margin of 7mm (AP and laterally)
10. There was agreement that a vascular expansion method would be
likely to be more reproducible in a multicentre trial setting
Conclusions: We conclude that with clarification and detailed modifications,
the RTOG guidelines would be suitable for use in the PIVOTAL multicentre
trial.Reference:1. Lawton, C.A. et al., RTOG GU Radiation oncology specialists reach concensus on pelvic lymph node volumes for high risk prostatecancer. Int J Radiat Oncol Biol Phys, 2009. 74(2):p.383-7
1300 poster
AUDIT OF ADAPTIVE RADIOTHERAPY PROTOCOL FOR FORWARD
PLANNED HEAD AND NECK IMRT
C. V. Brammer1 , A. Cousins1 , H. Bengiat1
1
N EW C ROSS H OSPITAL , D EANESLY C ENTRE, Wolverhampton, United
Kingdom
Purpose: The IMRT delivery protocol at our institution requires that the patient should be re-scanned and the plan re-optimised if the patient has lost >5
kg in weight or if there has been a reduction in the diameter of the patientsneck of more than 1cm at either the widest part of the neck pre-treament or
mod neck at the level of the hyoid bone. This audit was performed ro review
the appropriateness of the departmental guidlines and assess whether any
changes were required
Materials: All treatment schedules for patients with head and neck cancer
treated with IMRT ( 7 field forward planned without parotid sparing) over an 18
month period were reviewed. Variation in dose distribution between origional
plan and immediately prior to corrective action ( % of PTV recieving 95% and
90% of prescribed dose, maximum dose to organs at risk, change in size

CLINICAL IMPLEMENTATION OF RAPIDARC FOR THE TREATMENT
OF PAEDIATRIC HEAD AND NECK AND BRAIN TUMOURS AT UCLH
H. Mandeville1 , C. Stacey2 , Y. C. Chang1 , N. Fersht1 , K. Sullivan3 , S. A.
Moinuddin3 , I. Rosenberg2 , D. D’Souza2 , M. Gaze1
1U NIVERSITY C OLLEGE L ONDON H OSPITALS NHS F OUNDATION T RUST,
Department of Oncology, London, United Kingdom
2
U NIVERSITY C OLLEGE L ONDON H OSPITALS NHS F OUNDATION T RUST,Radiotherapy Physics Department, London, United Kingdom
3
U NIVERSITY C OLLEGE L ONDON H OSPITALS NHS F OUNDATION T RUST,Radiotherapy Department, London, United Kingdom
Purpose: To implement RapidArc volumetric modulated arc therapy for thetreatment of paediatric head and neck and brain tumours at UCLH and to
examine the potential benefits of this treatment.
Materials: During 2010, 8 patients, median age 9.5 years (range 2 to 18
years) were treated at UCLH with RapidArc (Varian Medical systems). Thiswas delivered using 6MV photons prescribed to the mean target volume
dose. Cases included: meningioma (2), optic pathway glioma, ependymoma,
retinoblastoma, embryonal (2) and alveolar rhabdomyosarcomas. Patientswere selected where improved sparing of critical organs at risk (OAR) compared to 3D conformal radiotherapy was achievable, and where proton therapy referral abroad was not possible. Specific consideration was given to thebones receiving >10Gy, taking into account potential growth and cosmetic
late effects. Assessment of treatment planning was undertaken as per ICRU
83, with the following parameters derived: D2, D50, D98, volume of 95% isodose, volume of PTV, dose to OAR, treatment time and monitor units (MU).
Homogeneity index (HI) was derived using (D2-D98)/ D50. Conformality index (CI) was derived using volume of 95% isodose/ volume of PTV. Quality
assurance with pre-treatment verification was performed for each plan.
Results: 5 patients were treated using 2 arcs and 3 with a single arc. Median
MU was 336 (range 254 to 470). Average beam on time was 60 secs for single
arc treatments and 150 secs for 2 arcs. Median (range) for other parameters:
D2=104.5% (102.5 to 107.1%), D50= 100.2% (99.7 to 100.7%), D98= 94.9%(92.1 to 95.7%), HI= 0.11 (0.07 to 0.12), CI= 1.13 (1.05 to 1.25). Wholevertebrae within the target volume region all received >10Gy and those notin the target volume region received <10Gy to ensure even future growth.
Significant sparing of brain, parotid and lacrimal glands was achieved withoutcompromising target volume coverage.
Conclusions: RapidArc has been safely and effectively implemented for thetreatment of paediatric head and neck and brain tumours at UCLH. Demonstrable benefits were observed in the patients treated, with highly conformal
and homogenous dose distributions achieved. In particular this treatment
offers the ability to reduce long term morbidity in this patient population by
reducing dose to uninvolved brain, improved sparing of parotid and lacrimal
glands, and accurate specification of dose to bony structures. Other benefits for children undergoing radiotherapy include the lower MUs required, incomparison to static field IMRT, which may reduce the risk of second malignancies, and the short treatment time, as they may be unsettled during
treatment or requiring general anaesthesia.
1302 poster
CTV – PTV MARGINS FOR IMRT FOR PATIENTS WITH A GYNAECOLOGICAL TUMOUR
S. Treur1
1
R ADIOTHERAPY C ENTRE W EST, Radiarion Therapy, The Hague, Netherlands
Purpose: To reduce the amount of normal tissue irradiation in patients witha gynaecological tumour an IMRT technique is developed. It is uncertain
whether the CTV-PTV margin of one centimetre, calculated for a 3D-CRT
technique, is also suitable for this new technique, since IMRT results in a more
rapid dose fall-off outside the PTV. The purpose of this study was to assess
the optimal CTV-PTV margins using IMRT for patients with a gynaecologicaltumour treated on a bellyboard (BB) device.

S 488

IMRT: C LINICAL IMPLEMENTATIONIMRT: C LINICAL IMPLEMENTATION

Materials: The study was divided into three parts. In the first part CTVPTV margins were defined by matching portal images with reference images
based on bony structures. We included nine patients who were treated on a
BB device with a four field box technique in 2007-2008. Daily portal images
were made in two directions (AP and LR). The random (σ ) and systematic (Σ)
errors are determined with SPSS and are used in Van Herks margin recipe(van Herk et al, 2000) to calculate the margins in three directions. In the second part the correlation between the matches of two different radiotherapists(RTTs) was determined and portal images were matched with the reference
images by two RTTs. Finally, both intra- and inter- fraction movement of thetarget volume also influences the necessary CTV-PTV margin. A literature
survey has been performed to investigate this phenomenon.
Results: For each direction 195 images were analyzed. The results wereused to calculate systematic and random errors in three directions for eachpatient and the research group (table 1). The data were normally distributed
and the correlation between the matches of the RTTs was very high (> 0,95)
for the translations. For the rotations lower correlations were found (>0,67),
probably because of the intrinsic sensitivity of the software used for matching.
Application of Van Herks margin recipe leads to CTV-PTV margins of: 6,1 mm
LR; 6,7 mm CC and 7,6 mm AP (table 1).

primary volume (1/10) (mean IMRT1 CI=2.35, IMRT2 =1.52, IMRT3=1.20).
Similar OAR doses were observed for all plans. Mean (range) small bowel
receiving V30 was 159(48-336)cc for IMRT1, 153(46-341)cc for IMRT2 and145(0-347)cc for IMRT3.Smaller volumes of genitalia receiving 20Gy and
40Gy (mean V20=84.6cc and mean V40=16.5 cc) with IMRT3 compared to
IMRT2 (97.3cc; 23.1cc respectively) and IMRT1 (103.6cc; 28.4cc respectively) were observed.The mean (range) normal tissue V5 was 88%(86-91%),
89%(85-95%) p=0.4 and 87%(84-90%) p=0.5 for IMRT1, IMRT2, and IMRT3
respectively.
Conclusions: All IMRT techniques appear to be equivalent in terms of OAR
dose despite the increase in conformality with the more complex phase2
IMRT plans. This surprising result is due to the fact that all the phase 2
volumes are small (for 9/10 less than 30% of Phase1) and is located awayfrom all OARs. 3F conformal boost is an acceptable solution, and will be
implemented as the standard approach at our centre. However, if there is
inguinal node involvement the inverse planned phase 2 may provide benefit.
1304 poster
INTENSITY MODULATED STEREOTACTIC TREATMENTS OF SMALLINTRACRANIAL TARGETS WITH ECLIPSE TPS AND MILLENNIUM
MLC
J. F. Calvo Ortega1 , J. Casals1 , E. Puertas1 , S. san José1 , S. Moragues1
1
H OSPITAL Q UIRÓN B ARCELONA, Department of Radiation Oncology,
Barcelona, Spain

Taylor et al. (2008) reported that margins of 0,8 mm LR; 7,1 mm CC and 7,0mm AP are needed to compensate for movement of the internal organs.
Conclusions: The overall margins are obtained by a quadratic summationof the margins for patient movement and the margins for movement of thetarget volume. The conclusion was that CTV-PTV margins of 7 mm (LR), 10
mm (CC) en 10 mm (AP) are necessary for IMRT for patients with a gynaecological tumour treated on a BB device. A further reduction of the CTV-PTV
margins depends mainly on the possibility of determining of and correcting
for movement of the cervix and uterus on a daily basis. Therefore further
research is needed.
1303 poster
INTENSITY MODULATED RADIOTHERAPY (IMRT) SOLUTIONSFOR ANAL CANCER TREATMENT USING UK ACT-II SCHEDULE
M. Hawkins1 , C. Brooks2 , Y. Lee2 , V. N. Hansen3
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Clinical Oncology,
Sutton, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Joint Department of
Physics, Sutton, United Kingdom
3
R OYAL M ARSDEN H OSPITAL T RUST & I NSTITUTE OF C ANCER R ESEARCH,
Joint Department of Physics, London, United Kingdom
Purpose: ACT-II UK anal cancer chemoradiotherapy protocol delivers 50.4Gy
at 1.8Gy/fraction/day(#) of radiotherapy (RT) in 2 phases: phase1 17# andphase2 11#. This schedule is not suitable for simultaneous integrated boost.
The aim is to compare the dosimetry of the composite plan of increasingly
complex IMRT for anal cancer treatment.
Materials: Ten consecutive CT datasets of patients with anal canal cancer
were identified. Phase1 planning target volume (PTV) included tumour, anal
canal and inguinal, peri-rectal, and internal/external iliac nodes; while phase2
included primary tumour and involved nodes only (3/10 had involved inguinal
nodes). Three types of composite phase1 and phase 2 IMRT plans were generated as follows: Phase1 inverse planned 7 fields (F) IMRT were the samefor all plans. Phase 2 plans varied: IMRT1 3F conformal, IMRT2 forward
planned 5F IMRT and IMRT3 inverse planned 5F IMRT. Coverage of phase
2 PTVs by 95% prescription isodose, homogeneity and conformity index (CI);the volume of OAR (small bowel, genitalia, and bladder) receiving more than20, 30, and 40 Gy (V20, V30, V40) were compared. To characterise the lowdose increase, normal tissue (body PTV) V5 was also studied. IMRT1 was
the reference plan.
Results: PTVs coverage and homogeneity indices for all 3 composite phase
1 and phase2 plans were similar: 95% PTV receiving >95% dose. However, the phase2 PTV CI improves with IMRT2 (mean=1.40) and IMRT3(mean=1.21) when compared to IMRT1 (mean=1.80). This difference appears to be greater for patients with inguinal nodes (3/10) or an irregularPurpose: To assess the feasibility of a commercial treatment planningsystem (TPS) for planning intensity modulated radiosurgery/radiotherapy(IMRS/IMRT) of small cerebral lesions by using a standard MLC.
Materials: Eclipse TPS (version 8.0, Varian Medical Systems) was configured and commissioned for standard field sizes (down to 3 cm x 3 cm) for
pencil peam convolution (PBC) algorithm and photon beams from a Varian Clinac 2100 CD equipped with a Millennium MLC (5 mm leaf width).
Five treatments (non-IMRT) for small targets (diameter ranged from 1 to 3cm) previously planned with a stereotactic-dedicated system (iPlan and m3
MLC, BrainLAB) were re-planned with Eclipse by using IMRT approach (Sliding Window). Coplanar and non-coplanar IMRS/IMRT plans were designed
and inverse optimization process was used. Patient dose was calculated using PBC with the smaller grid size available for this model on Eclipse (1.25mm).Clinical quality of Eclipse-based plans was assessed by comparing thetarget coverage (conformity index) with the iPlan-based ones. RTOG conformity index definition was used. Eclipse modulated plans were experimentally
checked in two steps. Experimental verification of the IMRT-based plans wasdone in two steps. First, absolute dose verification at isocenter point was performed by mapping the original IMRT plan into a polystyrene phantom containing a calibrated ion chamber detector (PinPoint). Second, fluence of eachindividual IMRT beam was verified using Portal Dosimetry tool, with EPID detector placed at 180 cm from linac focus (resulting integrated portal images
with 0.4 mm as pixel size at isocenter level). A 3% / 2 mm gamma criteria
was established for fluence map verification.
Results: Mean conformity index was 2.31 for m3-based plans and 1.99 forMillennium. Verifications of absolute dose for Eclipse calculations were within+/-3% in all the cases analysed. Planar fluence verifications met the 3%/2 mmcriteria for 97% of pixel analysed (range: 93%-99%).
Conclusions: Eclipse treatment planning system is suitable to produce clinically acceptable plans to treat small intracranial lesions by using Millennium
MLC and IMRT delivery. The use of Portal Dosimetry tool allows an IMRT
plan verification in a fast way before a single dose treatment delivery.
1305 poster
INTENSITY MODULATED-TOTAL MARROW IRRADIATION (IM-TMI):FIRST CLINICAL EXPERIENCE
B. Aydogan1 , M. Yeginer2 , A. Awan1 , M. Rank1 , P. Patel3 , B. Smith4 , D.
Rondelli3
1
T HE U NIVERSITY OF C HICAGO, Radiation and Cellular Oncology, Chicago,
USA
2
U NIVERSITY OF I LLINOIS, Molecular Biology of Oral Diseases, Chicago,
USA
3
U NIVERSITY OF I LLINOIS, Department of Medicine, Chicago, USA
4
U NIVERSITY OF I LLINOIS, Radiation Oncology, Chicago, USA
Purpose: To report the first ever clinical experience with fixed gantry intensity modulated-total marrow irradiation (IM-TMI) in a chemo-radiation preconditioning regimen. This is, to our knowledge, the first patient treatment casereported in the literature with this technique.
Materials: A patient with a recurrent multiple myeloma was treated in
our institutional phase I clinical trial for adjuvant linac-based IM-TMI and
chemotherapy. The patient was immobilized using a customized whole bodyalpha cradle and was simulated with 5 mm-slice CT scanning from top of thehead to the mid femur. All bones excluding the arms and lower extremities
were contoured as the clinical target volume and a 3 mm margin was added
to obtain the planning target volume (PTV). This method provided 7 mm to 12

mm PTV margin around the bone marrow. The organs at risk (OAR) including
the brain, lenses, lungs, liver, kidney, small bowel and heart were identified
and contoured by the attending physician. The IM-TMI technique consistedof three separate treatment plans; one for each of the H&N, trunk, and pelvis
regions. Extensive ion chamber, TLD, and film dosimetry verification ensured
the accuracy of treatment delivery and multi-plan matching. Precise positioning and alignment of all three isocenters were confirmed prior to the treatment
with AP and lateral port films. The treatment was delivered in a successive
manner starting with the H&N followed by the chest and pelvis repeating thesame verification process prior to treatment delivery of each plan to ensure
accurate patient positioning. The patient received a total of 300 cGy IM-TMI
dose in two fractions, 8 hours apart. Set-up error is analyzed by co-registering
port films and DRRs. Dosimetric consequences are calculated by shifting thedose matrix by the set up error determined.
Results: We achieved, with fixed gantry IM-TMI technique, a 95% coverageof the PTV with the prescription dose. OAR doses were reduced by 20% to
67% on average, which were significantly smaller than what would have beendelivered in a conventional TBI. Treatment time was on average 45 min and
35 min for the beam-on and set-up, respectively, using the Varian 21 EX linac
and MV imaging. Set up error was less around 5 mm while the dosimetricerror due to set up error was negligible for the real target, i.e. bone marrowitself.
Conclusions: Our results and analysis demonstrated that we successfully
and accurately treated the first patient with the fixed gantry IM-TMI technique. The patient tolerated the radiation treatment in addition to full courseof chemotherapy very well. No chemo-radiation related adverse effects wereobserved with excellent dosimetric results provided by IM-TMI. With the encouraging first patient experience, we plan to treat patients at increasing doselevels to assess the maximum radiation dose that can be safely delivered to
improve treatment outcome.
1306 poster
PET/CT GUIDED IMRT FOR LOCALLY ADVANCED PANCREATICCANCER
C. Ceylan1 , M. Guden1 , H. Bas1 , K. BERBEROGLU2 , N. Kucuk1 , A. Kilic1 ,K. Engin1
A NADOLU S AGLIK M ERKEZI, Radiaotherapy and Oncology, Gebze /Kocaeli, Turkey
2
A NADOLU S AGLIK M ERKEZI, Gebze / Kocaeli, Turkey
1

Purpose: IMRT for locally advanced pancreatic cancer (LAPC) offers a decrease in the toxicity associated with radiotherapy with keeping dose for critical organs under tolerance level and creating conformal dose distributions.
Biological information taken from PET is integrated to the anatomical information provided by CT could accurately characterize the tumor tissue to betreated for many cancer types. IMRT allows escalating dose to defined GTV
with PET/CT of pancreatic cancer while reducing dose at liver, kidneys andsmall bowel. Evaluation of IMRT of LAPC patients who had PET/CT guided
IMRT with concurrent Gemcitabine (G) was done using DVH, local control
and toxicity.
Materials: Nineteen patients were evaluated with localized but unresectablepancreatic disease between January 2008 and December 2010. Patientswere treated PET/CT guided IMRT and concurrent G during IMRT. PET andsimulation CT were performed with treatment position and immobilization toachieve better image fusion. GTV was defined using PET/CT which represents tumor in pancreas, an infiltration of tissues and involved nodes. The
CTV was defined using CT and CTV includes GTV and suspected area. The
PTV was obtained using expansion of CTV to consider setup variations. 4-7
IMRT fields were used to cover 95% of PTV volume with the prescribed dose.
Prescription to the PTV and CTV was 50.4 Gy, to the GTV was between 54
Gy and 60 Gy. Liver and kidney doses limited to volume of receiving 20 Gy
should be <20%. Kidneys were also limited to total volume of kidney receiving <10 Gy. Stomach and small bowel mean dose should be < 21 and < 28
Gy respectively. Maximum dose of spinal cord was held <45 Gy. Fraction
number of IMRT was 28-30 days.
Results: IMRT plans covered GTV which were defined using PET/CT median
96% of volumes with prescribed doses. The median CTV coverage was 93%.
While 20 Gy received liver volumes of patients was found >20% of volume(32%-22%) for six patients, mean dose of liver was <21 Gy. Median volume
exceeding 20 Gy was 17% for both kidneys. Doses of small bowels, stomachand spinal cord were found under dose constraints. Two patients required atreatment break during IMRT. Acute toxicity was very low. No late toxicities
were observed for any patients. Maximum follow up time was 15 months.
Patients underwent PET/CT to evaluate treatment after 3 months from IMRT.
First control PET/CT imaging reported decrease in SUV and size of primarytumor of 11 patients.
Conclusions: IMRT allows increased dose to the primary tumor and significant dose reduction to critical organs in pancreatic cancer. Our limited data of
LAPC demonstrate that PET/CT guided IMRT and concomitant G treatment
provides satisfactory local control rate and low acute and late side effects. Future studies may investigate dose escalation to the GTV with PET/CT guided
IMRT, stereotactic radiotherapy boost, and monitoring of local control.

S 489

1307 poster
TOMODIRECT: CLINICAL APPLICATION TO CURATIVE ANDPALLIATIVE CASES.
S. Presilla1 , K. Schombourg1 , N. Corradini2 , G. Ballerini1 , F. P. Alessandra1
1
C LINICA L UGANESE M ONCUCCO, Center of Radiotherapy, Lugano,
Switzerland
2
B ETH I SRAEL M EDICAL C ENTER, Center of Radiotherapy, New York, USA
Purpose: Aim of this work is: to identify which types of treatment can benefit
from TomoDirect (TD) IMRT irradiation compared with Helical TomoTherapy
IMRT (TH); to present the pre-clinical assessment and clinical application forsome selected tumor sites; to evaluate the treatment provided.
Materials: TH and TD plans were studied for the following tumor sites anddose prescriptions (dose per fraction, total dose): partial brain (2.5, 39.75Gy),sternum (3, 30Gy), whole breast (2, 50Gy), breast tumor bed (5/8, 10/16Gy),lung (2.5/2, 57.5/60Gy), vertebra (4/3, 20/30Gy), knee (4, 20Gy). For eachindividual treatment, the TD plan was evaluated in terms of coverage of the
PTV, sparing of OAR and normal tissue, and beam-on time. For treated plans,
the session time (from patient entrance to exit the bunker) was evaluated. For
each plan a pretreatment dose delivery verification (DQA) was performed withan array of 2D ionization chambers.
Results: For each region, cases were found where the TD plan was superior
to the TH one, with exception of the breast tumor bed. 27 patients (at least 1
for each region, except the tumor bed) were irradiated with the TD technique.
The mean PTV coverage was 100.4% (99-103%) with a mean standard deviation of 1.5% (0.73 2.78%). All PTVs received at least 95% of prescribed
dose to 99% of the PTV volume, with small deviations in some whole-breast
irradiations due to the build-up region. For all TD plans, the significant hot
spot (>1cc volume) were inferior to 107% of the prescribed dose. Concerning OARs sparing, all TD plans were judged acceptable from physicians andrespecting ALARA principle. Treatment results: mean beam-on time was321sec. (109-511sec). The mean session time was less than 15 minutes including positioning, MVCT and registration. DQA results: all cases showed a
gamma agreement superior to 95% with 3% of the maximum measured dose,
3mm DTA as passing criteria.
Conclusions: In general, the TD technique adds a degree of freedom to the
TomoTherapy system and allows a useful option in cases in which the helicaltreatment’s distribution of low dose is critical to healthy tissues and OARs.
The technique is also useful for sparing OARs adjacent to the PTV. TD iscomparable to TH irradiation both in terms of efficiency and effectiveness, inthe planning phase, during preparation (DQA) and application of the therapy
to the patients.In our center, the TD has become the standard technique forthe irradiation of the right breast. For the left breast, a 5-field technique has
given good results in difficult cases. The vertebral bone metastases can betreated quickly and with optimal coverage with 2/3 TD modulated fields: also
in this case, the technique has become our first option.
1308 poster
UTILISATION OF INTENSITY MODULATED RADIOTHERAPY (IMRT)ALLOWING ADEQUATE POST-OPERATIVE DOSES IN CARDIAC
SARCOMA
N. Bhalla1 , A. Botwood1 , J. Wylie1 , A. Choudhury1
1
T HE C HRISTIE NHS F OUNDATION T RUST, Clinical Oncology, Manchester,
United Kingdom
Purpose: Sarcomas constitute the majority of malignant cardiac neoplasms.
Overall prognosis of these tumours remains poor compared with extra-cardiac
sarcomas with median survival for non-metastatic disease ranging from 6
months to 18 months. The treatment of cardiac sarcomas is controversial.
Surgery has been the mainstay of treatment but survival improvements aresuggested by multi-modality therapy. However, radiotherapy data in this setting is limited as the delivery of adequate post-operative radiotherapy is restricted by adjacent lung and cardiac tolerances. We used inverse planned
IMRT in 2 patients to assess if the improvement in normal tissue sparing
would permit adequate post-operative doses to be delivered.
Materials: Patient 1. A 37 year old female with high grade left atrial myxoid
sarcoma underwent surgical excision with residual microscopic disease. She
received adjuvant radiotherapy 60 Gy in 33 daily fractions (5-field IMRT) using
8MV photons prescribed to mean dose to Clinical Target Volume (CTV). Using the Pinnacle planning system the CTV was delineated and extended 4cm
cranio-caudally. A 3D uniform 2cm margin was added to the CTV to produce
the Planning Target Volume (PTV) encompassing a volume of 551cm3 .Patient
2. A 43 year old male underwent incomplete excision of high grade left
atrial undifferentiated sarcoma with large extra-cardiac component. Palliative chemotherapy achieved stable disease, followed by 60 Gy in 33 daily
fractions to the residual mass (7-field IMRT), using 8MV photons prescribed
to mean dose to CTV. On the Pinnacle planning system the residual disease
was delineated as Gross Tumour Volume (GTV) and a 2cm margin added togive CTV. A further 0.5cm 3D uniform margin was then added to form the
PTV, which encompassed a volume of 685cm3 .
Results: Patient 1: maximum heart-1cm3 was 63Gy. Cardiac V60 was 9%achieved by limiting dose delivery to the unaffected ventricles. Lung V20 was

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34%. Maximum spinal cord-1cm3 was within tolerance at 33Gy. Eight centimetres of oesophagus was encompassed within the 95% isodose.Patient 2:
maximum heart-1cm3 was 63Gy. Cardiac V60 was 10% and lung V20 was
27%. Maximum spinal cord-1cm3 was within tolerance at 44Gy. Eleven centimetres of oesophagus was encompassed within the 95% isodose.Acute toxicity was mild with both patients experiencing grade 1 oesophagitis and erythema. Patient 1 had grade 2 acute pneumonitis that resolved with steroids.
At 57 months follow-up patient 1 has no recurrence and normal left ventricular function. With 7 months follow-up patient 2 has stable disease and mildly
impaired left ventricular function (ejection fraction 53%; pre-chemotherapy
58%).
Conclusions: By utilising IMRT and applying strict dose constraints acceptable sparing of normal tissues can be achieved when delivering radiotherapy
for cardiac sarcomas. This allows standard postoperative doses to be safely
delivered with acceptable toxicity.

IMRT: Rotational therapies
1309 poster
COMPARISON OF CYLINDRICAL PHANTOM BASED (DELTA4) AND
EPID BASED (EPIQA) DOSE DISTRIBUTION VERIFICATION FOR
HEAD AND NECK CANCER PATIENTS UNDERGOING RAPIDARC™
RADIATION THERAPY.
B. Smulders1 , F. Kjaer-Kristoffersen1 , A. Logadottir1 , W. Sapru1 , C. A.
Kristensen1 , L. Specht1 , J. P. Bangsgaard1
1
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of Radiation
Oncology, Copenhagen, Denmark
Purpose: In our clinic the majority of head and neck cancer (H&N) patients
undergoing radiotherapy receive a RapidArc™(RA) treatment. This techniqueinvolves a simultaneous integrated boost, where the patients receive 66 or 68
Gy in 2 Gy fractions to the primary tumour and lymph node metastases, depending on size; areas at high and low risk for microscopic spread receive 60
and 50 Gy respectively. The spinal cord dose limit is 45 Gy. A safety margin(PRV) with a dose limit of 50 Gy is delineated to eliminate over dosage tothe spinal cord. In our clinic the risk of over dosage is minimized using daily
CBCT image guidance. The dose prescription and dose limits are in agreement with the Danish Head and Neck Cancer Group criteria. In order to verify
the dose distribution an comparison study was performed with a cylindricalphantom (DELTA4) and an EPID (EPIQA) based verification system.
Materials: Our study includes 50 H&N cancer patients, treated at our department. The dose was verified with the DELTA4 system. DELTA4 is a cylindricalphantom with two perpendicular plates with matrices of ionization chambers.
The phantom is positioned on the treatment couch with one plate in sagittal
position intersecting the position of the spinal cord. The patient plans, consisting of two RA fields, were recalculated on the CT-scanned phantom anddelivered to the phantom. The results were interpreted using the standard
DELTA4 criteria used in our clinic: dose difference (85% of all dose points d< 3%), Distance to agreement (DTA, 95% of all points < 3mm) and Gammavalue (95% of all points d < 3% and < 3mm). The dose to spinal cord wasevaluated. A subgroup of 20 patients was verified with EPIQA. This systempresents results only as a gamma value. Therefore, new gamma criteria for
H&N patients verified with EPIQA had to be established.
Results: A good agreement was achieved between calculated and measured
dose distribution on the DELTA4 phantom. 90% of the patient plans met the d,
DTA and gamma criteria. The residual 10% showed close agreement with thecriteria and only disagreement at insignificant parts of the dose distribution.
In the spinal cord no over dosage was found in 24 of 50 patient plans andin the residual 26 only minor over dosage of up to 5% in a few points, which
is well within the end limit of 50 Gy.A fare agreement was achieved between
calculated and measured dose distribution using the EPIQA system. Results
showed that 9 out of 20 patient plans had less then 95% points and 1 patientplan had less than 90% points meeting the gamma criteria. Measurementsof these failed plans with the DELTA 4 system showed that the result of the dcriteria was close to the 85%, which was acceptable for clinical use.
Conclusions: A good agreement between calculated and measured dose
distribution was found for both DELTA4 and EPIQA measurements for H&N
patients receiving RA. No major over dosage to the spinal cord was found.
A new gamma criteria of 90% of all points with d < 3% and < 3mm for the
EPIQA system was established in our clinic.
1310 poster
WHOLE BODY DOSE, USING GAMMA H2AX MEASUREMENT,FOLLOWING RADIOTHERAPY: A COMPARISON OF VOLUMETRICMODULATED ARC THERAPY (RAPIDARCTM) WITH STATIC FIELDINTENSITY MODULATED RADIOTHERAPY (IMRT)S. Sivabalasingham1 2 , M. Worku1 , S. Short1 2
1

UCL C ANCER I NSTITUTE, London, United Kingdom
U NIVERSITY C OLLEGE L ONDON H OSPITAL NHS T RUST, Department of
Oncology, London, United Kingdom

2

Purpose: Both static field intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (RapidArcTM ) offer optimised target dose conformality. However, RapidArcTM requires a lower number of monitor units and’beam on’ time compared to static field IMRT, and therefore may produce alower whole body dose. Phosphorylation of the histone H2AX (γ H2Ax) isa well established marker of DNA double strand breaks that has been validated as a measure of whole body dose in patients exposed to diagnostic
and therapeutic irradiation. The aim of this study is to quantify γ H2Ax fociin peripheral blood mononuclear cells of patients undergoing radiotherapy forbrain tumours and to compare induced foci numbers in patients undergoing
RapidArcTM and static field IMRT.
Materials: Patients undergoing radical treatment with radiotherapy to thebrain, but without concomitant chemotherapy, were included. Patients weretreated with RapidArc(TM) or static field IMRT using 5-7 fields. Peripheral
blood samples were collected from each patient at the following time points:
i.baseline; ii.weekly- prior to and 30 minutes after one treatment fraction on
the same day each week; iii.2 and 6 weeks following completion of treatment. Whole blood was centrifuged to separate lymphocytes, which werethen fixed and stained for fluorescent immunocytochemistry. 150 cells per
sample were visualized. γ H2AX foci were identified and counted using confocal microscopy.
Results: There is a significant increase in mean foci per cell in post radiotherapy treatment samples compared to pre treatment samples, following both radiotherapy techniques (RapidArc(TM) : 0.215 foci per cell pre treatment and 0.422 foci per cell post treatment, p=0.015; static field IMRT: 0.350
foci per cell pre treatment and 0.707 foci per cell post treatment, p=0.001).
However, throughout the course of treatment, there is a smaller increase infoci numbers following radiotherapy in those patients receiving RapidArc(TM)compared to static field IMRT (0.165 foci per cell with RapidArc(TM) , 0.358
foci per cell with static field IMRT, p=0.167). Similarly in both delivery techniques, there appears to be no significant difference in foci numbers post
treatment when samples taken at different times during treatment were compared (for example with RapidArc(TM) : 0.417 in week 1 and 0.317 foci in week
2, p=0.827) and foci numbers return to baseline by 6 weeks following completion of radiotherapy.

THERAPY
S. Lalondrelle1 , D. Willis23 , C. Nalder3 , E. Selvadurai4 , A. Mitra5 , P. R.
Blake1
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiotherapy, London,
United Kingdom
2
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, Physics ,Norwich, United Kingdom
3
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Physics, London, United
Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom
5
U NIVERSITY C OLLEGE H OSPITAL, Radiotherapy, London, United Kingdom
Purpose: To compare dosimetry using 3DCFRT, inverse planned IMRT andvolumetric arc therapy with Rapidarc in the treatment of uterine cervix andpost-operative endometrial cancer.
Materials: CT datasets of 10 cervix and 5 post-operative endometrial (POPE)
patients were included. For each dataset a 3 or 4 field conformal and an inverse planned IMRT plan were optimised. Additionally for POPE these plans
were also compared to a virtually simulated non-conformal 3 or 4 field (VS)technique. 5 of the cervix cases and 3 endometrial cases were also selected
for further Rapidarc plans. Planning objectives for the PTV were defined asminimum and maximum doses of 47.9Gy and 53.9Gy for cervix, 42.75Gy and48.2Gy for endometrium. Constraints for organs at risk are detailed in Table
1.Plans were compared using DVH parameters for the PTV and OAR and the
V50% dosebath.

1312 poster

1311 poster
A DOSIMETRIC COMPARISON OF 3D CONFORMAL (3DCFRT),
IMRT, AND RAPIDARC FOR GYNAECOLOGICAL PELVIC RADIO-

45◦ ; dose rate: 600 UM/min). Plans for Tomotherapy were optimised using a
0.287 pitch, a 2.5 cm field and a modulation factor of 4. Plans were evaluatedbased on the volume receiving between 95% and 105% of the prescribed
dose for PTV against D2% for the OAR. The choice of D2% was to minimize
the impact of dose calculation inaccuracies and sampling approximation in
DVH calculation. In order to test the Rapidarc algorithm, the plans performed
with AAA-algorithm was recalculated with Montecarlo.
Results: In Figure the "Pareto front" for the most stressed situation wasshown. For all simulations RapidArc met less of the optimization criteria
while Tomotherapy was able to produce the most homogeneous dose andhas the capability to conform dose distributions better than RapidArc. The
results concerning less stressed situations show that the distance between
the two fronts depends on all three parameters (dose difference, concavity of
PTV and distance between OAR and PTV), being proportionally reduced forless stressed situations. The preliminary re-calculation Rapidarc plans with
Montecarlo Algorithm make worse in terms of D2%.

Conclusions: Pareto-front analysis is a powerful tool to better understandpotentials and limits of advanced delivery/optimization techniques especiallyduring the phases of implementation and clinical activation, even in the case,here investigated, of stressed conditions.
Results: PTV coverage was similar for all 3 techniques for cervix treatments(mean D95%, SD: 3DCFRT 49.5Gy, 0.5; IMRT 49.4Gy, 0.14; RA 49.3Gy,
0.11). RA resulted in fewer hotspots compared to 3DCFRT (p=0.01) and
IMRT (p=<0.01)(D2%, SD: 3DCFRT 52.7Gy, 0.54; IMRT 52.4Gy, 0.24; RA
51.4Gy, 0.09). Small bowel dose, measured by the dose to the hottest 17cc
bowel, was reduced to equivalent extent with RA (p=0.01) and IMRT (p=0.04)
compared to 3DCFRT. Similar reductions in dose to rectum and bladder wereobserved with IMRT and RA.For POPE, 3DCRFT improved PTV coverageover VS fields (mean D95% 30.8Gy VS, 43.5Gy 3DCFRT), with both IMRT
(44.2Gy, 0.1)and RA (44.2Gy, 0.1)improving coverage further. As with cervix
plans, RA resulted in less hotspots and RA and IMRT provided equivalent
improvements in dose to OAR.IMRT and to a greater extent RA resulted in a
reduction in the dosebath as measured by the V50% compared to 3DCFRT(mean reduction in V50% = 5% IMRT, 20% RA).
Conclusions: In cervix radiotherapy, IMRT and RA provide equivalent target
coverage compared to 3DCFRT. Both IMRT and RA improve PTV coveragefor POPE treatment and reduce dose to OAR for cervix and POPE comparedto 3DCFRT. RA results in the least hotspots and has the smallest dosebath.

Fig. 1: Mean change in foci per nucleus following radiotherapy in static field
and arc based IMRT
Conclusions: γ H2AX foci in peripheral blood lymphocytes can be used toassess whole body dose in patients receiving different radiotherapy delivery
methods. The smaller increase in foci numbers following RapidArc(TM) , compared to static field IMRT, may reflect the lower whole body dose and be clinically relevant and advantageous in certain situations, especially when aiming
to reduce the long term risks of low dose radiation. These data suggest that
this assay could be used to compare relevant whole body exposure deliveredby different IMRT techniques

S 491

A PARETO FRONT COMPARISON BETWEEN HELICAL TOMOTHERAPY AND RAPID ARC IN THE SITUATION OF A SINGLE OAR
ADJACENT TO A CONCAVE PTV
R. Azzeroni1 , C. Fiorino1 , M. Alber2 , G. M. Cattaneo1 , R. Calandrino1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
2
K LINIKUM RECHTS DER I SAR , TU M ÜNCHEN, Biomedical Physics,
München, Germany
Purpose: The performances of the RapidArc (Varian Inc.) technique werecompared against Helical Tomotherapy in a geometrically well defined, controlled situation.
Materials: Within an homogenous elliptical phantom, one cylindrical organ
at risk wascreated in the centre of the concavity outside a concave PTV;
the PTV concavity and the distance between PTV and OAR (from 0 to 1.5cm) were varied while the organ at risk was set to receive at most 60% of
the prescription dose and the prescribed dose to PTV as homogeneously as
possible. In order to make a "Pareto Front" to compare the two techniques,different relative weights for PTV and OAR constraints were applied. To avoid
the influence of the planner, a single pass approach was undertaken, setting
desired priority at the start of the optimization for the Tomotherapy system
and at the third resolution level for Rapidarc (Eclipse Aria 8). A baseline optimization for RapidArc consisted of two complete arcs (collimator rotation:

1313 poster
CAN SINGLE ARC SMARTARC VMAT REPLACE DMPO-IMRT FORCOMPLEX TARGETS?
G. Smyth1 , J. Bedford1 , V. Hansen1 , P. Wai1 , A. Warrington1
1

T HE I NSTITUTE OF C ANCER R ESEARCH AND T HE R OYAL M ARSDEN NHSF OUNDATION T RUST, Joint Department of Physics, Sutton, United Kingdom

Purpose: The aim of this project was to determine if single arc volumetricarc therapy (VMAT) treatment plans could be produced that were comparable to existing step-and-shoot direct machine parameter optimisation intensity
modulated radiotherapy (DMPO-IMRT) techniques at this centre for head andneck (H&N) and prostate and pelvic node (PPN) cancers.
Materials: Ten patients previously treated with DMPO-IMRT - five for eachclinical site - were replanned using the SmartArc module of Pinnacle3 v9.0
(Philips Healthcare, Fitchburg, WI) for an Elekta Synergy linear accelerator(Elekta AB, Stockholm, Sweden) with 1 cm MLC leaf width at isocentre. H&N
patients were originally planned with a 7-field IMRT technique, to mean dosesof 65 Gy and 54 Gy in 30 fractions for primary and nodal planning target volumes (PTVs) respectively. PPN patients were originally planned with a 5-field
IMRT technique to mean doses of 60 Gy and 47 Gy in 20 fractions to prostateand pelvic node PTVs respectively. Single arc VMAT plans were producedwith the aim of optimisation to at least equal the clinical IMRT plan in termsof PTV coverage and organ at risk (OAR) sparing, although in practice a balance of these factors was necessary. VMAT and IMRT plans were comparedin terms of clinical PTV and OAR constraints, treatment delivery time andmonitor units (MU) delivered. Plan verification for all VMAT plans and four ofthe five original H&N IMRT plans was performed by delivering the treatment
to a Delta4 phantom (Scandidos AB, Uppsala, Sweden) and recording the
proportion of diodes with a gamma index (3 % / 3 mm) of less than or equal
to unity.
Results: Treatment plans showed comparable results for PTV coverage andOAR sparing (Table 1). Treatment times were reduced by an average of 32 %for H&N cases (6 min 48 s for VMAT, compared with 10 min for IMRT) and 51% for PPN cases (4 min 6 s compared with 8 min 23 s for IMRT). Delivered
MUs were on average 15.6 % less than the equivalent IMRT plans for H&N(537.8 ± 45.7 MU (1SD) compared with 639 ± 67.0 MU) and 16.3 % lessfor PPN (568.8 ± 42.4 MU compared with 679.7 ± 54.1 MU). The mean
proportion of Delta4 diodes with a gamma index (3 % / 3 mm) of less than orequal to unity was 95.6 % for VMAT H&N, compared with 99.3 % for the four
original IMRT H&N plans, and 97.5 % for VMAT PPN.

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IMRT: R OTATIONAL THERAPIES
1316 poster
DOES INTERDIGITATION CHANGE THE DOSE PRECISION AND
DELIVERY TIMES OF VMAT TREATMENTS?
I. Hazell1 , A. Bertelsen21 , C. Brink21
1
O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
Denmark
2
U NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark

Conclusions: Single arc SmartArc VMAT can produce plans equivalent toclinical DMPO-IMRT techniques at this centre for these sites. Further investigation into improving plan verification results, particularly for H&N cases,
is ongoing and focused on reducing the contribution of segments with narrow MLC leaf pair separations. Clinical implementation of VMAT for complex
target geometries is planned.
1314 poster
DELIVERING TBI USING VMAT: A DOSIMETRIC PROOF OF PRINCIPLE.
W. Ingram1 , Y. Lee1 , C. Sanne2 , F. Saran3 , A. Warrington1
1
R OYAL M ARSDEN H OSPITAL, Department of Medical Physics, London,
United Kingdom
2
U NIVERSITÄTSKLINIKUM D ÜSSELDORF, Klinik für Strahlentherapie undRadioonkologie, Düsseldorf, Germany
3
R OYAL M ARSDEN H OSPITAL, Department of Clinical Oncology, London,
United Kingdom

Purpose: Working towards the clinical use of Volumetric Modulated Arc Therapy (VMAT) to deliver conformal Total Body Irradiation (TBI) we have investigated the suitability of Pinnacle v9.0’s SmartArc facility to inversely plan deliverable treatments and its ability to model the resulting dose accurately.
Materials: VMAT dose distributions representing TBI treatments and elements thereof have been designed using the Pinnacle planning system anddelivered. These distributions have been studied with reference to the expected dose distribution using the 0.6cc ionisation chamber, Gafchromic EBT
films placed in the CIRS IMRT thorax phantom, and the Scandidos Delta4
diode array to validate Pinnacle v9.0’s suitability for generating these complex
distributions, the result of the summation of a number of complex and small
fields as well as the contribution of scattered radiation.In addition to studies of"full" clinical emulations a number of test fields were studied in order to isolate
the sources of suspected artefacts. These include 1cm x 10cm, 10cm x10cm
and complex field VMAT plans to test surface effects and poorly modelled
scattered radiation. The test plans were also used to establish if sufficient
dose is deposited in the surface of the phantom to justify the removal of the’beam spoiler’.
Results: The planning system’s ability to predict the gross features of its own
inversely planned distributions are demonstrated using Gafchromic film, ionisation chamber and the Delta4 diode array. Initial point dose measurementswith ionisation chambers for conformal plans were within 1% agreement withcalculated dose. Initial studies using the Delta4 show only 74.3% of readings pass a gamma (3%/ 3mm) test. A number of artefacts consistent withthe effects listed above are also apparent beyond what can reasonably be
accounted for by experimental uncertainty as shown in Figure 1. Test fieldstudies are continuing in order to determine the magnitude of these contributions and to better characterise the beam model to predict VMAT plans using
SmartArc.

Figure 1: Gamma (3%/3mm) comparison of planned and measured doses
demonstrates features such as bony spine insert and streaks associated withsmall field widths in using EBT film in CIRS thorax phantom.
Conclusions: Due to the significant number of discrepancies between themeasured and predicted doses for these distributions and their sensitivity
to the VMAT plans’ constituent field shapes conditions (such as limitations
regarding minimum field dimensions) must be introduced into the inverse
planning criteria before reliable dose distributions can be expected. Since
SmartArc (as provided with Pinnacle v9.0) does not at present offer suchflexibility this approach remains to be proved in principle.
1315 poster
DEVELOPING A QA PROGRAM TO INCORPORATE RAPIDARC
IMRT DELIVERY
C. Meehan1
1
R OYAL M ARSDEN H OSPITAL, Department of Physics and Radiotherapy,
London, United Kingdom
Purpose: As with the introduction of any new clinical technique careful consideration has to be given to how this technique can be verified and monitored. 3 tests have been incorporated into our routine machine QA to evaluatedelivering of a RA beam. Patient QA has developed along side our standard
IMRT patient QA.
Materials: Machine QAFlatness and symmetry is measured using a Profiler2 device located in the gantry head. The test compares a 20x20cm fielddelivered for a standard open field at 400MU/min with a 20x20cm field delivered with gantry rotation through a full 360deg arc with constant dose rate of
400MU/min and another arc with changing dose rate. Dose delivered for a
RA plan is measured using our standard output set up with a 0.6cc calibrated
farmer chamber at 5cm deep in a water phantom. The final test comparesa RA delivery with the same RA plan but delivered at gantry 0. Integrated
images are acquired on the EPID for each delivery and compared. Patient
specific QAPatient verification is carried out using a PTW729 ion chamberarray in the Octavius phantom. To gain confidence with RA patient verification point doses are also measured using a semi-flex chamber in a cylindricalphantom at different dose levels in the plan. (PTV and OAR positions).
Results: Machine QAFlatness and symmetry of the beam delivered withgantry rotation and changing dose rates are within 1% in both GT and ABof the standard static field. Output of the RA plan is within 3% of expectedvalues. EPID images of RA delivery compared to gantry 0 delivery using
gamma criteria 1%/2mm are above 99% points passing. Patient QAPTW
results for coronal plane gamma criteria 3%/3mm are within 93.5%-100%
points passing for all patients (20 patients). Point dose measurements for the
PTV and OAR are within +/-3% (PTV AV +0.92%, SD 1.02 : OAR AV -0.24%,
SD 2.07).
Conclusions: With some extra machine QA checks RA has been able to be
introduced smoothly into the department. RA forms an extension of our existing IMRT delivery and QA tests have been developed using setups already inplace. With these extra machine QA tests confidence has been gained in thisnew delivery technique and careful monitoring of the machines performanceis possible. Patient QA has been verified to the same tolerances as IMRT.

Purpose: The use of modulated arc therapy (VMAT) has decreased treatment times compared to IMRT by 35% [R&O 95, 2010, 142] due to the continuous delivery of radiation with variation of dose rate in discrete steps. The
new accelerator control system IntegrityTM by Elekta allows the dose rate tovary continuously instead of in discrete steps of 50% as in the earlier control
systems. Like in the step from IMRT to VMAT this additional degree of freedom has showed to decrease the treatment time by further 33% [R&O, 96
suppl 1, 2010, S567(book of abstracts, ESTRO 2010)]. IntegrityTM , which iscurrently under clinical evaluation for Elekta at our institution, enables the useof interdigitation of the MLC’s. Thus, it has become possible to irradiate two
or more separate areas at the same time. In this study it is explored, whether
this additional flexibility gives an even further reduction in treatment time andMU and if there is any change in precision of the delivered dose.
Materials: For each patient two treatment plans were made by the same
physicist, one plan with use of interdigitation and one without. The optimisation volumes, constraints and objectives were optimised for each plan. For
VMAT planning the SmartArc algorithm in Pinnacle3® was used. Both plans
were clinically acceptable according to our standard guidelines and approvedby an experienced radiation oncologist such that they could be used for clinical treatment. Treatment delivery time and number of MU’s were compared.
Finally, the precision of the delivered dose, measured with a Delta4® phantom,
was assessed by gamma evaluation.
Results: When interdigitation is allowed, the optimisation algorithm utilises
this additional flexibility. The resulting treatment plans with and without leafinterdigitation can be delivered clinically. Preliminary results on the first 6
patients show that the mean treatment delivery time is 146 sec using interdigitation and 145 sec without. Similar finding is made for the mean number
of MU; 426 MU using interdigitation and 428 MU without. For the measured
dose the mean gamma pass rate is 98.5% for both the plans using interdigitation and those who does not (dose and distance criteria 2% of 2Gy and2mm, respectively).
Conclusions: The use of interdigitation in IntegrityTM , the new control systemfrom Elekta, is feasible. Even though more degrees of freedom are added tothe planning phase no gain in either dose precision, delivery time, or numberof monitor units is observed with the planning algorithm used in this study.
The result might be different with another planning algorithm that could utilize
interdigitation in a different way.
1317 poster
DOSE RATE ISSUES IN TOTAL BODY IRRADIATION DELIVEREDWITH HELICAL TOMOTHERAPY
A. Mazal1 , S. CANEVA2 , C. Lesven1 , P. Francois1 , S. Zefkili1 , Y. Kirova3 , S.
Helfre3 , A. Fourquet3
1
I NSTITUT C URIE, Medical Physics, Paris, France
2
I NSTITUT C URIE, Medical Physics, Saint Cloud, France
3
I NSTITUT C URIE, Radiation Therapy, Paris, France
Purpose: To investigate instantaneous dose rate delivery for Total Body Irradiation with Helical Tomotherapy
Materials: While Bone Marrow Irradiation (BMI) has already been appliedwith Tomotherapy in clinical practice, some clinical teams are still reluctant
to make such a large step to replace Total Body Irradiations. A more conservative approach could be to start with the classical treatment irradiating
the full body while protecting the lungs, to evolve at a second step with techniques protecting other additional organs and tissues while keeping an homogeneous dose to the rest of the body, before moving at a last step towards BMI.In this study, we have investigated the instantaneous dose ratedelivered to critical structures like the lung during TBI helical Tomotherapy
delivery. A set of treatment plans with different pitch and modulation factors
were performed. These plans were performed first on phantom (TomoPhantom,Gammex, Middleton) and next on whole body patient images. For eachplan, a set of clinical protocols were applied, varying dose-volume contraints
applied to critical structures. Patient delivery quality assurance plans (DQA)
were performed and dose rate was measured using A1SL ion chamber (Std.
Imaging) and Tomotherapy electrometer at selected points in the phantom
volume/dose distribution. Tomotherapy measurement system allows collecting and integrating the charge collected as a function of time, with a minimum
sample time of 100ms.These settings are required to measure instantaneous
dose rate during each beam projection of 400ms average time.
Results: While the mean dose rate value achieved at the measurement
points for one of the optimized plans was in good agreement with the required value of 0.1-0.2Gy/min, we have found high dose rate peaks of about
3-4 times the mean value. Peak amplitude depend on the plan optimization

S 493

parameters used in the inverse planning process which determine the MLC
leaf mean open time per projection

Conclusions: The biological and clinical incidence of high instantaneous
dose rate is unknown in the case of TBI, but in principle, clinical users prefer
to avoid it, especially in pediatric cases. The results of our measurements,
analysis and proposals to reduce the high dose rate peaks while delivering
the prescription dose to the whole body is presented, as well as other practical issues when planning using a Tomotherapy unit for TBI.Conflict of Interest:
Supported in part by a research agreement with TomoTherapy,
1318 poster
DOSEMETRIC COMPARISON BETWEEN TOMOTHERAPY AND INTENSITY MODULATED RADIOTHERAPY FOR NASOPHARYNGEALCANCER
P. Teo1 , M. Kam2 , B. Yu3 , P. Kong3 , H. Geng4 , Y. W. Ho3 , J. Poon4 , T. Lam41
H ONG KONG S ANATORIUM & H OSPITAL, 1st Clinical Oncology Department,
Happy Valley, Hong Kong (SAR) China
2
P RINCE OF WALES H OSPITAL, 1st Clinical Oncology Department, Hong
Kong SAR, China
3
H ONG KONG S ANATORIUM & H OSPITAL, 2nd Radiation Therapy Department, Happy Valley, Hong Kong (SAR) China
4
H ONG KONG S ANATORIUM & H OSPITAL, 2nd Radiotherapy Department,
Happy Valley, Hong Kong (SAR) China
Purpose: This study compared the dosimetric performance of helical tomotherapy (HT) with 9 fields dynamic multileaf intensity modulation radiotherapy (DMLC-IMRT) in the treatment of nasopharyngeal carcinoma (NPC).
Materials: Fourteen NPC patients were studied: Group A early T-stages(T1/T2; n=7) and group B late T-stages (T3/T4; n=7). Each case was plannedwith both HT and DMLC-IMRT (Eclipse 8.0) planning system using the same
set of dose-volume constraints for the organs at risk (OARs). Both plansdelivered 70Gy and 65Gy to at least 95% and 99% of the planned target volume (PTV) respectively, and no more than 1% of the PTV received higher
than 80Gy. Dosimetric comparison between HT and DMLC-IMRT was madefor the tumor control probability (TCP, normal tissue complication probability(NTCP), conformal indexes (CI), homogeneity index (HI), and various dosevolume parameters of the PTVs and the OARs. Statistical analysis was performed using paired t-test.
Results: All the HT and the DMLC-IMRT plans complied with the dose requirements for PTV. There was no statistically significant difference in CI or
HI between HT and DMLC-IMRT plans for both groups of patients. Both HT
and DMLC-IMRT plans achieved 99.9% TCP. For both group A and B patients,
HT plans achieved significantly better dose-sparing of brainstem (Dmax: 52± 1 Gy vs. 31 ± 5 Gy; p<0.01), spinal cord (Dmax: 42 ± 2 Gy vs. 21 ± 1
Gy; p<0.01), larynx, parotid gland, eyeball, middle ear and temporal lobe. For
Group A patients (early-T stage), HT was more capable of preserving parotid
function than DMLC-IMRT (Dmean: 32 ± 2Gy vs. 26 ± 4 Gy; p0.05). For
Group B patients (advanced-T stage), the optic nerves (Dmax: 42 ± 6 Gy vs.
26 ± 6 Gy; p<0.01) and chiasm (Dmax: 48 ± 7 Gy vs. 36 ± 9 Gy, p<0.01)
were better protected from high dose by using HT.
Conclusions: HT and DMLC-IMRT had comparable target coverage for
PTVs for all T-stage NPC. Significantly better dose-sparing of OARs wasachieved using HT. Optic pathway protection was more evident for advanced
T-stage whereas parotid protection was more pronounced in early T-stage
disease.

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IMRT: R OTATIONAL THERAPIES

IMRT: R OTATIONAL THERAPIES

1319 poster
GEOMETRICAL ACCURACY AND IMAGE QUALITY OF CT RECONSTRUCTIONS FROM VMAT PORTAL IMAGES
M. Thomas1 , G. Poludniowski1 , P. Evans1 , S. Webb1
1
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Joint Department of Physics, Sutton, United Kingdom
Purpose: It has recently been shown that recognisable CT images can beproduced from portal images acquired during volumetric modulated arc therapy (VMAT) treatments (G Poludniowski et al 2010 Phys. Med. Biol. 555635). Ultimately, these images may be registered with a pre-treatment CT toverify the patient position during the radiotherapy treatment. Each portal image used in the reconstruction is shifted according to the corresponding MLC
positions as measured by the linac control system. Errors in this process will
result in blurring and/or mispositioning of the reconstruction, which would inturn reduce the accuracy of a clinical image registration. In this study, we
assess the accuracy with which the isocentre is located in these reconstructions. We also apply standard measures of CT image quality to acquired
phantom images.
Materials: An 8-mm diameter ball bearing phantom was positioned accurately at the radiation isocentre of a Beam Modulator-equipped Elekta Synergy linac using projections with two opposing collimator rotations at four cardinal gantry angles. Three different single VMAT arc clinical treatments weredelivered to the phantom and the images acquired and reconstructed as described in the work cited above. The resulting 3D data sets were thresholded at half their maximum value. The distance between the centroid of thehigh-density points and the origin of the reconstruction was measured in all
three directions. The same three patient treatments were also delivered to
the CATPHAN phantom with the isocentre placed (a) in the spatial resolution
test object and (b) at the centre of the uniformity test object.
Results: On repetition of the ball bearing positioning images, the residual
error in the position was less than 0.1 mm in each direction. The ball bearing
was clearly visualised in the reconstructions (on the left in the figure). The
volume of the thresholded region was within 2.5% of the physical volume of
the ball bearing. The centroid of the thresholded region was found to deviate
from the expected position at the centre of the reconstructed image by 0.3 mm(root mean square across all direction and patients). The maximum observed
deviation was 0.5 mm. In the spatial resolution images, 4 line pairs per cm
were visible (on the right of the figure). The standard deviation of CT values
in the central 2 cm cube of the uniform phantom images varied from 5 to 14%.

second 350 anticlockwise arc, joined together into a single beam, with a simultaneous linear couch motion of pitch 10 cm (total motion 30 cm), thereby
forming a piecewise helical trajectory. Control points were distributed every
7 throughout the trajectory, corresponding to every 0.2 cm of couch translation. The multithreaded inverse planning algorithm optimised fluence, sequenced the beam and optimised segment weights. A final dose calculation
was performed using Pinnacle3 (v9.0) with the linear translation handled as
multiple isocentres. Three plans were considered, one unconstrained in aperture shape (Plan A), one with each arc loosely constrained to a third of thePTV (Plan B), and one with apertures encouraged to form feathered junctions(Plan C). The plans were then delivered on an Elekta Synergy linear accelerator and the dose was verified using a Delta4 phantom on a motorised trolley,
simulating couch translation.
Results: All three plans provide a homogeneous dose to the PTV, with amean homogeneity index, (D2 D98)/Dmean, of 0.091. The plans are also
conformal, with a mean conformity index, V80/PTV, of 1.55 (Figure 1a). Plans
B and C require more monitor units than plan A (714.5 and 713.1 respectively,
versus 478.3) because less of the PTV is irradiated at one time. However, thedelivery time is reduced for plans B and C compared to plan A (15:38 mins
and 14:07 mins respectively, versus 23:48 mins) because there is less multileaf collimator leaf motion. Verification shows good agreement for all plansbetween calculated and measured dose, with a mean of 97.1% of measurements within 4% and 4 mm of calculated dose (Figure 1b).

Conclusions: The study shows that the dose given to the spinal cord in
RapidArc treatments in the H&N area, are weakly dependent on the change
in the distance from the tumor surface to the spinal cord. From this it canbe concluded that in most cases it is probably not necessary to re-plan thepatient due to the dose given to the spinal cord, when tumor shrinkage isseen, mainly in those cases when the dose planned to the spinal cord lies
close to the limit for the dose used at our clinic (45 Gy). These results are
the first step in a larger study, where the goal is to set-up simple strategies forwhen to re-plan the H&N patients receiving arc-treatment.

Conclusions: The VMAT CT algorithm places the isocentre with an accuracyof 0.3 mm which is easily good enough for clinical registration. Two different
measures of image quality show that image quality is considerably short ofthe standard of kV cone-beam CT but they provide a quantitative baseline for
improvement of the images. Image quality is highly variable depending on
plan-specific factors. Further studies are in progress to assess registration ofclinical images to planning CT scans.
1320 poster
HELICAL VMAT FOR TREATMENT OF THE CRANIOSPINAL AXIS
J. Bedford1 , Y. Lee1 , F. Saran1 , A. Warrington1
T HE I NSTITUTE OF C ANCER R ESEARCH AND T HE R OYAL M ARSDEN NHSF OUNDATION T RUST, Sutton, United Kingdom

1

Purpose: Volumetric modulated arc therapy (VMAT) facilitates efficient delivery of intensity-modulated radiation therapy (IMRT). Linear couch motion
can be simultaneously applied to generate a helical arc trajectory. This study
investigates treatment planning and delivery of helical VMAT for the craniospinal axis in order to improve dose homogeneity in the planning target
volume (PTV) and reduce dose to the organs at risk.
Materials: The PTV was defined as the whole brain with a 0.3 cm uniform
margin, plus the spine clinical target volume with an anterior-posterior margin of 0.5 cm and a lateral margin of 1.0 cm. Prescribed dose was 23.4 Gy
in 13 fractions. The AutoBeam program (v5.0) was used to generate treatment plans consisting of a 350 anticlockwise arc, a 350 clockwise arc and a

Purpose: The study was performed to investigate how tumor shrinkage affects the dose given to head and neck patients’ spinal cord when treated with
RapidArc.
Materials: The study included 20 patients receiving radiotherapy for cancer
in the head and neck area. All the patients were treated with arc-treatment(RapidArc, Varian). Cone-BeamCT scans (CBCT) were acquired daily with
the On-Board Imager (Varian), and used for verifying the patient set-up and tocorrect the position before each daily treatment session. The contour for the
spinal cord was transferred off-line from the planning CT to the CBCT scans.
The original plan was thereafter recalculated on the CBCT scans, where monitor units and MLC movements were kept fixed. This was done to estimate theeffect of the size of the patient’s tumor on the dose given to the spinal cord ineach daily session. The maximum dose to the spinal cord (Dmax,spinal cord)
was found on each of the CBCT scans, where Dmax,spinal cord was the maximum dose given to at least 2% of the contoured volume of the spinal cord.
As a first approximation, was the size of the tumor indicated with the distanced defined in Fig 1, where d was taken as the largest measured distance fromthe tumor surface to the spinal cord.
Results: Dmax,spinal cord and d were found for each patient on all the daily
CBCT scans. The results for two of the patients are shown in Fig 1. The
figure shows how Dmax,spinal cord is weakly dependent on the change ind (∆d) and therefore on the change in the size of the tumor. The results
for the other patients show similar dependency on d. For different patientsthe planned Dmax,spinal cord will be different and thus give different fitted
curves for each patient. If, on the other hand, the results for the patient groupstudied are normalized in that way that Dmax,spinal cord (0) =100% for all
the patients, the results can be fitted with one linear curve, similar as can beseen in Fig 1. These results will be shown and discussed in further details,
as well as threshold for ∆d to keep Dmax,spinal cord below the allowed limit,
will be presented.

1322 poster

Conclusions: VMAT with a piecewise helical trajectory offers a convenientand efficient means of planning and delivering IMRT treatment for the craniospinal axis. This technique allows the linear accelerator to treat volumes
considerably longer than its maximum aperture length. An appropriate choiceof aperture constraint should provide an optimal combination of plan quality,
monitor units and delivery time. We are grateful to Elekta Ltd for their supportof this work. We acknowledge NIHR funding to the NHS Biomedical ResearchCentre.
1321 poster
HOW DOES TUMOR SHRINKAGE AFFECT THE SPINAL CORD
DOSE GIVEN IN RAPIDARC TREATMENTS?
A. Logadottir1 , B. Smulders1 , J. P. Bangsgaard1 , C. A. Kristensen1 , L.
Specht1
T HE F INSEN C ENTER - R IGSHOSPITALET, Department of Radiation
Oncology, Copenhagen, Denmark

1

IMPLEMENTATION OF VMAT FOR INTRA-CRANIAL TUMOURS: A
PLANNING COMPARISON
G. Lamb1 , S. Smith1 , A. James2 , M. Glegg1
1
T HE B EATSON W EST OF S COTLAND C ANCER C ENTRE, Department ofClinical Physics and Bio-Engineering, Glasgow, United Kingdom
2
T HE B EATSON W EST OF S COTLAND C ANCER C ENTRE, Department ofClinical Oncology, Glasgow, United Kingdom
Purpose: The Varian VMAT solution, RapidArc was implemented for thetreatment of intra-cranial tumours in August 2010. This planning study compared conventional RT with single, double and multiple non-coplanar arc
VMAT treatment plans for intra-cranial sites that had planning target volumes(PTVs) overlapping organs at risk (OARs).
Materials: 6 patients with intra-cranial PTVs were planned using conventional conformal RT, and using 3 different VMAT planning techniques. The
first VMAT planning technique utilised a single complete arc, the second
utilised two concentric coplanar arcs and the third technique utilised four non
coplanar semi arcs, positioned to avoid entry through eyes. The PTV wasseparated into high and lower dose regions receiving 60Gy and 54Gy in 30

S 495

fractions respectively. The lower dose region encompassed overlapping critical OARs. The objectives were to cover 95% of the PTVs to 95% of the dose
(CI95) and 99% of the PTVs to 90% of the dose(CI90) , without violating OAR
constraints. Dose volume histograms for PTVs and OARs were compared.
Results: Semi arc treatment plans achieved all CI90 and CI95 PTV andOAR dose constraints for all patients. In contrast, the double arc techniqueachieved all the constraints for only 1 out of 6 patients while the single arcplans did not achieve all constraints for any patient. Double and single arcplans were able to achieve the mean brain dose constraint for only 1 patient,however other OAR constraints were met. Conventional RT plans did notachieve the PTV or brain dose constraints for any patient. Normal tissue conformity index (NI CI 95%) was comparable for all VMAT treatment plans (0.97-0.99) and significantly reduced for conventional treatments (0.65 -0.75).
Conclusions: VMAT achieved better PTV coverage when compared withconventional RT. Similar OAR doses were achieved, except for normal brain
tissue, where the dose was greater with conventional RT, single and double arc VMAT plans. Semi arc non-coplanar treatment plans produced better
PTV coverage than single or double arc VMAT plans while achieving OAR
dose constraints. Semi arc non-coplanar treatment plans will now be used asa class solution when planning intra-cranial tumours that have PTVs overlapping OARs.
1323 poster
ONCENTRA MASTERPLAN VMAT WITH SIMULTANEOUS INTEGRATED BOOST: PLANNING AND EVALUATION FOR DIFFERENTCANCER CASES
S. Cilla1 , F. Deodato2 , G. Macchia2 , C. Digesù2 , D. Sabatino1 , M.
Massaccesi2 , V. Picardi2 , M. Ferro2 , P. Bonomo2 , L. Caravatta2 , A.
Fidanzio3 , A. Piermattei3 , A. G. Morganti2
1
C ATHOLIC U NIVERSITY - C ENTER FOR H IGH T ECNOLOGY R ESEARCH AND
E DUCATION IN B IOM, Medical Physics Unit, Campobasso, Italy
2
C ATHOLIC U NIVERSITY - C ENTER FOR H IGH T ECNOLOGY R ESEARCH AND
E DUCATION IN B IOM, Radiotherapy Unit, Campobasso, Italy
3
C ATHOLIC U NIVERSITY, Physics Unit, Rome, Italy
Purpose: At our Institution, the transition from fixed field IMRT to Volumetric
Modulated Arc Therapy (VMAT) technique stems from the need to significantly reduce the treatment time while maintaining the dosimetric plan accuracy. The objective of this study was to evaluate the dosimetric quality and thedelivery efficiency of VMAT plans with Simultaneous Integrated Boost (SIBVMAT) for complex-shaped target volumes. Four different cancer settings(head and neck, prostate, rectum and pancreas) were selected.
Materials: Twenty patients treated with SIB-VMAT in clinical protocols using
Elekta Precise linacs were selected. They included five head-and-neck, fiveprostate, five rectal, and five pancreatic cancer cases. SIB-VMAT plans werecompared with fixed field SIB-IMRT plans, assumed as benchmark. All plans
were generated with Oncentra Masterplan TPS, with VMAT plans optimized
in dual arc modality. For head and neck cancer cases, three targets were
simultaneously irradiated over 30 daily fractions. Doses of 67.5, 60.0 Gy and55.5 Gy were prescribed to primary tumor, high-risk lymph nodal regions andlow-risk nodal region, respectively. For prostate, rectal and pancreatic cancer
cases, two target volumes were defined for each patient and simultaneously
irradiated over 25 daily fractions (prostate cases: 65 Gy to prostate plus seminal vesicles and 45 Gy to pelvic lymph nodes; rectal cases: 57.5 Gy to GTV
and 45 Gy to lymph nodal region; pancreatic cases: 55 Gy to primary tumor
and 45 Gy to pancreas and primary lymphatic drainage). Plan evaluation
statistics included various dosimetric endpoints for the target volumes andnormal organs. MUs number and treatment times were analyzed to score thetreatment efficiency.
Results: Dual arc VMAT showed similar target coverage as SIB-IMRT plans,with slightly better conformity indices in all cancer cases. All dosimetric endpoints were fulfilled with no significant differences in OARs sparing, withslightly improvement observed in the head-neck cases. In all cancer cases
MUs were reduced by 20-30%. Treatment times (excluding patient set-up andimaging procedure) were reduced from 14-20 minutes (according to the typeof treatment) to less than 5 minutes for all patients, regardless of cancer site.
Conclusions: Oncentra Masterplan produced SIB-VMAT plans with highconformal dose distribution, similar target coverage and similar or even better OARs sparing compared to benchmark SIB-IMRT plans. However, VMAT
was able to provide approximately a 50-70% reduction in treatment time, withall patients treated within 5 minutes. Patient compliance to treatment has
been significantly increased and the risk of intra-fractional motion potentiallyreduced. SIB-VMAT is currently our standard approach for IMRT technique.
1324 poster
RAPID DOUBLE ARC REPLACES DYNAMIC IMRT IN PROSTATE
BED AND STOMACH RADIATION THERAPY
G. Zeng1 , J. Murphy1 , Q. Zhan1 , Y. Wang1 , Y. Wang1 , J. R. Tsao1 , T. S.
McGowan1 , M. MacPherson1
1
C REDIT VALLEY H OSPITAL, Department of Radiation Oncology, Mississauga, Ontario, CanadaS 496

IMRT: R OTATIONAL THERAPIES

IMRT: R OTATIONAL THERAPIES

Purpose: Varian Eclipse (ver 8.9) added multiple-arc optimization in its progressive resolution optimizer (PRO). The multiple arc fields are complementary and have more degrees of freedom in shaping dose, and the aperture
based MLC motion doesn’t need carriage split for large targets. Therefore,
this new technique is suited to treat irregular or large targets. Here, we report
our work in applying double arc (two arc fields) to prostate bed and stomach
radiation and its advantages over using dynamic IMRT.
Materials: 10 prostate bed pts and 12 stomach pts, previously planned ortreated with dynamic IMRT, were retrospectively planned using double arc.
The dose prescriptions were 66Gy/33 for prostate bed and 45Gy/25 for stomach. Double arc plans were compared to IMRT plans. We set the collimatorof the two arc fields to 45 and 315 degree respectively. This combination
maximizes MLC beam shaping and minimizes the leaf leakage effect. We
developed a generic objectives template for each site to speed up planning
process. The optimization parameters were designed to yield quality plans
for all cases.
Results: Double arc plans show superiority to IMRT plans in target dose,
OAR sparing, dose conformability, delivery and planning efficiency. Table 1
shows the prostate bed results averaged over 10 pts: PTV was better covered
with a lower max dose; rectum dose was reduced by 1Gy to 2Gy; Bladderdose was comparable with that of IMRT; femoral head dose was decreasedby 9Gy; arc plans had smaller 50% and 25% dose volume than IMRT plans;
the monitor units were down by 30%, from ~950 to ~660MU. Stomach site
results showed the same advantages: Arc plans were more conformal with
better PTV coverage; mean liver dose was down by 2Gy and kidney dose fellby 1Gy; MUs for arc plans were ~400MU compared to ~900MU for IMRT. The
delivery time for both sites is ~3 min for double arc while ~5 min for IMRT.
Arc planning time is ~30mins using the standardized templates, while IMRT
planning required hours for some cases depending on individuals.

Conclusions: The data demonstrate Varian rapid arc, with the multiple-arc
capability, can produce high quality plans with efficiency and has the potential
to replace conventional dynamic IMRT. Our work also suggests that automating arc planning may be feasible with well-designed optimization parameters.
Our center has started treating all prostate bed and stomach pts with double
arc.
1325 poster
REFERENCE DOSIMETRY FOR TOMOTHERAPY : A MULTI-CENTRE
VALIDATION.
B. De Ost1 , B. Schaeken1 2 , N. Reynaert3 , V. Althof4 , D. Van den
Weyngaert1
1
U NIVERSITY R ADIOTHERAPY A NTWERP, Antwerp, Belgium
2
BEL DART, Diepenbeek, Belgium
3
C ENTRE O SCAR L AMBRET, Lille, France
4
RISO, Deventer, Netherlands
Purpose: The aim of this study was to validate a new protocol for reference
dosimetry; for different tomotherapy units.
Materials: A static field will not be used for patient treatments in tomotherapy,
but can be a valuable part of the routine machine QC. A composite field canbe used to link the measured dose for this field to the dose predicted by theplanning system. The IAEA/AAPM published a new formalism for the reference dosimetry of small and non standard fields, in this work, two new typesof reference fields are defined: a static machine specific reference field (msr)
and a plan class specific reference field (pcsr). To implement this protocol
for tomotherapy we have chosen to work with 2 msr fields : a 5cm x 10cm
static field and a 5cm x 10cm rotational (no modulation, no table in the beam)
field and one pcsr (a plan prepared on the planning system with modulationand table movement). The plan-class specific reference field of choice is a 5
cm or 2.5cm planned modulated field, for a region of interest with a diameterof 10 cm and a length of 5 cm, within the cylindrical phantom. Measurements were performed in a rectangular water phantom for the static msr field
and in an home-made cylindrical water phantom for the rotational msr field
and the pcsr field. Measurements were carried out on three Hi-art tomotherapy systems in Antwerp, Lille en Deventer. Dose measurements in all three
centres are performed in water with the same exradin A1SL 0.056 cm3 ionchamber (calibrated in terms of ND,W,) and alanine (calibrated against water calorimetry at PTB) as it is available from BELdART (Belgian dosimetry
Audits in RadioTherapy). Also the local ionisation chamber following the local
dosimetry protocol was used.
Results: Mean static output for the three centres was 6.258 Gy/min(1SD=0.047). Rotational output was 6.270 Gy/min (1SD=0.062 ). The output for the different machines can be compared since all machine are basedon the same (golden) standard. Results are found in good agreement for
both protocols: the ratio of the local stated dose and the IAEA stated dose

was 1.000 (1SD=0.004). Alanine confirms the ionization chamber results.
The average ratio of the rotational output and the static output was 1.002(1SD=0.003).
Conclusions: Since there is no international accepted dosimetry protocol forthe determination of the absolute dose in tomotherapy, the presented formalism seems to be provide a good concept for reference dosimetry.
1326 poster
RETROSPECTIVE VMAT DOSE RECONSTRUCTION ON CBCT
BASED ON DELIVERY AND MLC DYNAMIC LOG FILES RECORDED
DURING TREATMENT
K. Lee1 , S. Chan1 , M. Cheung1 , M. Chau1 , K. Cheung1 , K. Kam1
1
P RINCE OF WALES H OSPITAL, Department of Clinical Oncology, Hong
Kong SAR, China
Purpose: To develop a methodology for retrospectively reconstructing thedose delivered to head-and-neck (HN) patients in a VMAT treatment basedon (1) on-treatment Cone Beam Computed Tomography (CBCT) and (2) dynamic log-files which record the actual leaf positions, gantry angles, and delivered monitor units (MUs) during the VMAT delivery.
Materials: A phantom and two HN cases were chosen in this work. For eachcase, on-treatment CBCT was taken for setup verification and subsequent
dose reconstruction. After the VMAT treatment was delivered, two log-files
were retrieved: (1) MLC log-file which recorded the actual leaf positions andrespective gantry angles every 50 ms from the MLC workstation and (2) delivery log-file which recorded the actual delivered MUs and gantry angles atthe control points defined in the VMAT plan from the machine control unit.
Through the common parameter of gantry angle recorded for both log files,
the actual delivery status such as leaf positions, delivered MUs, and gantry
angles for every control points were re-constituted. This data was converted
into a DICOM radiotherapy plan (RP) file using in-house developed software
written in Python code (Python Software Foundation, Wolfeboro Falls, NH).
The DICOM RP file was then imported into Eclipse treatment planning system (Varian Medical Systems, Palo Alto, CA) and the actual delivered dose
was reconstructed on the on-treatment CBCT acquired. The work flow andfeasibility of implementing such a maneuver in a clinic were also evaluated.
Results: A retrospective dose reconstruction procedure has been established and applied for VMAT. For the case in which the tumor shrinkage wasslight, the reconstructed and planned doses were consistent to within 3-5%
in high dose region. The DVHs of the target and other organs do not havesignificant differences. However, large dosimetric changes (10-15%) wereobserved for the other case with tumor shrinkage, indicating the need for replanning or adaptive measure to be taken.
Conclusions: VMAT dose reconstruction offers a pragmatic way to monitor
the actual dose delivery at a particular fraction and provides dosimetric information critical to adaptive radiation therapy. It is feasible to implement thismaneuver if a minor re-engineering of the existing work flow is adopted.
1327 poster
SINGLE ARC VMAT FOR HEAD AND NECK CANCER: A PRELIMINARY STUDY
C. Fiandra1 , V. Balcet2 , M. Rampino2 , F. Munoz2 , R. Ragona1 , C. Piva2 , U.
Ricardi1
1
U NIVERSITA DI TORINO, Department of Medical and Surgical Sciences,
University of Torino, S. Giovanni Battista Hospital, Italy, Torino, Italy
2
O SPEDALE M OLINETTE U NIVERSITY OF T URIN, Department of Medical
and Surgical Sciences, University of Torino, S. Giovanni Battista Hospital,
Italy, Torino, Italy
Purpose: Arc Therapy has emerged as a technique to overcome some of thelimitations of fixed field treatment. The primary objective for the study was tocompare VMAT and IMRT plans by evaluation of 1) dose to targets, 2) doseto organs at risk, 3) delivery times and 4) monitor units.
Materials: A retrospective planning study was designed to compare IMRT
with VMAT. We included ten patients with nasopharyngeal and oropharyngeal cancer that were treated between 2008 and 2010 with ss-IMRT at our
Institution. A simultaneous integrated boost (SIB) technique with two or threedose levels was planned in all patients. Mean prescription dose for PTV1 was
70 Gy, for PTV2 was 62.14 Gy (59.40- 66.50 Gy) and for PTV3 was 57.31 Gy(54.12-61.25 Gy). For each plan, 7 coplanar fields were used, with an average of 50 segments. Target coverage was defined as V95%. The dose heterogeneity in PTVs was assessed by the dose difference D5%-D95%. IMRT
treatment times were obtained from record and verify system (VISIR), as patients were previously treated. VMAT plans were delivered and the beam-on
time was measured based on the record and verify system (MOSAIQ, Elekta).
Results: Mean doses to PTVs were similar in the highest PTVs, while weobserved less overdosage in the intermediate dose PTVs. A difference between the two techniques in favour of VMAT was noted in dose homogeneity
for the high dose PTV, as mean D5%-D95% was 10.66% for VMAT versus
16.73% for IMRT. With VMAT, V95% substantially increased by 4 percentage
points compared to IMRT for high dose PTV, while V90% slightly increased

from 95,78% to 97,67%. Mean maximal doses (D1%) for IMRT (109,63%)
were reduced with VMAT(107,575%) and the same reduction was observedfor "hot-spots" with a V110% of 1.19% for IMRT and 0,22% for VMAT. For
omolateral parotid gland IMRT mean dose reached 34,38 Gy versus 38,80
Gyin VMAT. We noticed no improvement in parallel structures as controlateral parotid gland (Dmean 29,54 Gy and 35,91 Gy for IMRT versus VMAT)
and oral cavity (Dmean 40,07 Gy and 42.07 Gy for IMRT versus VMAT). The
average number of MU per fraction was 1144 for ss-IMRT plans and 892 for
VMAT thus indicating a mean reduction of about 28%. Plans delivery on the
Synergy accelerator showed a 50% mean reduction in treatment time: an average of 23 minutes for IMRT delivered with Elekta Precise translated in 11,5
minutes average for single arc VMAT.
Conclusions: The VMAT treatment plans were clinically acceptable but lesssparing of OARs was observed in respect to ss-IMRT in some few cases, thatsurely leave open doors to static IMRT in selected cases. Both reduction of
MUs and delivery time showed an high delivery efficiency for VMAT plans.
1328 poster
THE EFFECT OF PHOTON BEAM ENERGY ON VMAT TREATMENT
PLAN QUALITY FOR ADVANCED PROSTATE CANCER
M. Pasler1 , H. Wirtz1 , J. Lutterbach1 , D. Georg2
1
G EMEINSCHAFTSPRAXIS FÜR S TRAHLENTHERAPIE, Singen am Hohentwiel, Germany
2
M EDICAL U NIVERSITY V IENNA , AKH, Medical Radiation Physics, Vienna,
Austria
Purpose: To compare both plan quality criteria and the dosimetric accuracyof VMAT plans using 6-, 10- and 15MV photon beams for prostate cancer
including seminal vesicles and lymph nodes.
Materials: In this retrospective planning study, VMAT plans were generated
with the Pinnacle TPS V9.0 treatment planning system for 10 prostate cancer
cases using the SmartArc- algorithm. Each plan contained 2 target volumes:
PTVboost included the prostate and seminal vesicles, PTVPC+LN contained
the boost and lymph nodes. VMAT plans were created for 6-, 10- and 15MV
photon beams using a single arc.Plan evaluation statistics included homogeneity index (HI = (D5%-D95%)/ D50%), conformity index (CI = V95%/ Vtarget), Dmax and equivalent uniform dose (EUD) for OARs. Treatment time andnumber of monitor units were assessed to compare delivery efficiency. Dueto the small sample size we deliberately did not do statistical tests. Dosimetricverification of the plans was performed with a 2D ion chamber array placedin a full scatter phantom. The gamma index criterion (3%, 3mm) was applied
for plan evaluation.
Results: Homogeneity index for PTVPC+LN was 0.13 ± 0.02, 0.15 ± 0.02
and 0.14 ± 0.02 for 6-, 10- and 15MV plans, respectively. The results of HI
for PTVboost show no variation for different photon energies (HIboost = 0.11
± 0.03).In PTVPC+LN, mean conformity index was 0.98 ± 0.02, 0.99 ± 0.03
and 0.98 ± 0.01, and CI for PTVboost was 1.09 ± 0.02, 1.11 ± 0.03 and1.10 ± 0.03 for 6-, 10- and 15MV plans, respectively.EUDs for organs at risk
showed no particular differences between high and low energy photon plans.
However, slightly lower maximum doses to OARs were found in 10-MV planscompared to 6- and 15-MV plans. For example, Dmax for bladder was 78.7
± 1.2, 76.9 ± 1.8 and 77.9 ± 1.8 and the rectum received a Dmax of 76.4
± 1.1, 75.2 ± 1.2 and 75.9 ± 1.4 in 6-, 10- and 15MV plans, respectively.
Normal tissue around the target received lower EUD in higher photon energyplans, as seen in figure 1.The number of MU per 2Gy fraction was 475 ± 18,447 ± 20 and 465 ± 20 for PTVPC+LN and 388 ± 30, 384 ± 22 and 416±
23 for PTVboost in 6-, 10- and 15MV plans, respectively. All plans weredelivered in less than 3 minutes.Dosimetric verification resulted in a mean
gamma value of 0.35 ± 0.08, 0.39 ± 0.09 and 0.41 ± 0.05, all plans met
the clinical specification of > 95% of dose points passing the gamma index
criterion.

S 497

photon beam energy plans in target coverage is very small. Regarding normal
tissue sparing, lower EUDs were found using high energy photon beam plans.
1329 poster
THE IMPACT ON THE PLAN QUALITY AND QC RESULTS DUE TO
THE CHOICE OF DIFFERENT COLLIMATOR ANGLES IN VMAT FORPELVIC TUMOURS
H. Benedek1 , E. Wieslander1 , T. Knöös1 , C. Ceberg2
1
S KÅNE U NIVERSITY H OSPITAL AND L UND U NIVERSITY, Radiation Physics,
Lund, Sweden
2
L UND U NIVERSITY, Medical Radiation Physics, Lund, Sweden
Purpose: To investigate how different collimator angles affects the plan quality and QC measurement results for VMAT planning and delivery. The planquality is compared with the Pareto front method and the Pareto index.
Materials: Several VMAT treatment plans were generated for differed collimator angles. A pareto optimal set of plans were generated and comparedfor each collimator angle. The Pareto sets were created by plotting the meandose to the bowel as a function of the under-dosed PTV volume. The optimization was made in Oncentra master plan, (Nucletron BV). The plans werecreated with different importance of the bowel max dose objective. The plans
were made to be delivered on a Elekta synergy linac (Elekta Oncology systems). A quantitative meter of the plan quality called pareto index was also
calculated for all the Pareto sets. Treatment plans with dual arcs and single
arcs were generated. Quality control measurements where made for every
collimator angle. The measurements where performed using a Delta 4 diodearray (Scandidos AB). 3D gamma evaluation was used to evaluate the QC
results.
Results: The Pareto set representing 35 collimator angel (Figure), single arc,
is situated below the set representing 5single arc. This indicates a better OAR
sparing for collimator angle 35 with the same under dosage as for 5 collimatorangle. To achieve similar OAR sparing with 5 a dual arc plan is necessary,
thereby prolonging the delivery time. One arc takes 2.5 min to deliver hence
two arcs takes 5 min. The QC pass rate for the 5 plans are about 99% andfor the 35 plan about 90%.
Conclusions: By choosing the right collimator angle the quality of a VMAT
plan can be improved. For the case shown in the figure, a single arc planwith 35 collimator angle has similar OAR sparing and target coverage as adual arc 5collimator plan. This improvement in plan quality can shorten thedelivery time because only one arc is needed. However, the QC results are
not as good for the 35 plan. Depending on the QC protocol used, the plancan be rejected and has to be re planed.

1330 poster
THE ROBUSTNESS OF CLINICAL VMAT TREATMENT PLANS TO
MLC LEAF POSITIONING ERRORS
U. Isacsson1 , K. Nygård1 , K. Wikström1 , E. Blomquist1
1
U PPSALA U NIVERSITY H OSPITAL A KADEMISKA S JUKHUSET, Departmentof Oncology, Radiology and Clinical Immunology, Uppsala, Sweden

Conclusions: Contrary to our expectations, the difference between the three

Purpose: The use of Volumetric Modulated Arc Therapy (VMAT) treatment
plans for radiotherapy treatments of head and neck patients is increasing
mainly due to shorter treatment times compared to IMRT. However, accurate

S 498

IMRT: T REATMENT PLANNING AND OPTIMIZATIONIMRT: R OTATIONAL THERAPIES

multileaf collimator (MLC) leaf positioning plays an essential role in the effective implementation of VMAT. The aim for the present work is to investigate therobustness of the clinical treatment plans and the sensitivity of current patient
specific QA-measurements with respect to MLC leaf positioning errors.
Materials: Ten head and neck patients previously planned and treated with a
VMAT technique was used in the study. The original plans were exported andthe leaf positions were changed to simulate five different systematic positioning errors of the MLC-banks. That is + 1 mm and + 2 mm of all leaf positions
in each leaf bank (X1 and X2). Negative and positive errors make the leaf
end-to-end distance smaller and larger, respectively. The fifth plan simulateda parallel shift of 2 mm of the two banks at the same time. After the MLC
leaf positioning errors were introduced the plans were re-imported and recalculated in the treatment planning system. Measurements, with a Delta-4®
system, for the modified plans, were compared with calculated doses of theoriginal plans. The agreement between calculation and measurement wasevaluated using gamma index with 3%/3 mm, 3%/2 mm, 3%/1 mm, 4%/3
mm, 5%/3 mm, 8%/3 mm, 12%/3 mm criteria
Results: Comparing the original treatment plans with the plans representing
MLC leaf positioning errors show that the target coverage decreases significantly or the dose to the organs at risk increases significantly and the sensitivity of current patient specific QA-measurements were large for all plans
with simulated MLC leaf positioning errors except for the fifth plan simulatinga parallel shift of the two leaf banks.
Conclusions: Theresults demonstrate that the robustness, of the clinical
VMAT plans, to MLC leaf positioning errors was low. However, the current
patient specific QA-measurements are sensitive to these errors and will detect them.
1331 poster
THE ROLE OF ROTATIONAL ARC THERAPY IN GASTRIC CANCER
TREATMENTL. Szczurek1
1
T HE I NTERNATIONAL O NKOTHERAPY C ENTER, Department of Medical
Physics, Poznan, Poland
Purpose: To evaluate quantitatively the benefits of using Rotational Arc
Therapy (ProArc) and Intensity Modulated Radiation Therapy (IMRT) vs. 3Dimensional Conformal Radiotherapy (3D-CRT).
Materials: The retrospective study was performed for 25 patients with gastriccancer to irradiate planning target volume (PTV) up to 45Gy in 25 fractions.
For each patient were created three plans with using IMRT step and shootwith 7 coplanar beams, ProArc technique (Rotational Arc Therapy) with 1
arc and 3D-CRT with 4 fields. The evaluation and comparison was done
based on the final DVHs using Kruskal Wallis test. Doses given to 95% of
PTV (DPTV95), to 40% of liver (DL40), to 75% of left kidney (DKL30), to
30% of right kidney (DKR75), to 1% of spinal cord (DSC1) were reported
as a percentage of the total does. Mean doses were calculated for DVHs of
PTV, liver, kidney left and right.Additionally the time of treatment for IMRT and
ProArc techniques were compared with U Manna-Whitneya test.
Results: Mean DPTV95 for ProArc, IMRT and 3D-CRT were 98.8%, 99.9%
and 97.4% respectively. Mean DPTV50 for ProArc, IMRT and 3D-CRT were101.5%, 101.4% and 101.1% respectively. Mean DL40 for ProArc, IMRT
and 3D-CRT were 66.6%, 66.2% and 67.1% respectively. Mean DKL30
for ProArc, IMRT and 3D-CRT were 68.6%, 68.0% and 72.1% respectively.
Mean DKR75 for ProArc, IMRT and 3D-CRT were 17.1%, 17.2% and 20.0%
respectively. Mean DSC1 for ProArc, IMRT and 3D-CRT were 88.1%, 88.2%
and 92.4% respectively. Mean dose for PTV for ProArc, IMRT and 3D-CRT
were 45.7Gy, 45.5Gy and 45.5Gy respectively. Mean dose for liver for ProArc,
IMRT and 3D-CRT were 26.3Gy, 26.8Gy and 27.4Gy respectively. Mean
dose for left kidney for ProArc, IMRT and 3D-CRT were 24.2.Gy, 21.0Gy and
24.4Gy respectively. Mean dose for right kidney for ProArc, IMRT and 3DCRT were 14.1Gy, 14.4Gy and 16.3Gy respectively. Significant differenceswere revealed for ProArc and IMRT for the mean number of monitor units per
fraction; 240MU and 265MU (21 segments) respectively (p<0.001).
Conclusions: Target dose coverage was significant improve with ProArc and
IMRT as compared with 3D-CRT with simultaneously relevant decreasing
doses in healthy tissues. Additionally the patient comfort due to reduce treatment time were improved for ProArc techniques as compared to IMRT stepand shoot .
1332 poster
THE USE OF MAPCHECK SYSTEM TO PERFORM PRE-CLINICALQA FOR RAPID ARC PLANS: ANALYSIS OF GAMMA HISTOGRAMS
L. Perna1 , G. M. Cattaneo1 , G. Rinaldin1 , V. Ardu1 , R. Azzeroni1 , C.
Fiorino1 , R. Calandrino1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
Purpose: Rapid Arc (RA) is a volumetric intensity modulated arc techniqueto plan and deliver highly conformal dose distribution. Quality assurance programs (QA) recommend pre-clinical verification of RA plans to guarantee theagreement between calculated and measured map fluencies. The purpose of

the study was to report the results of pre-clinical dosimetry with a planar detector and the analysis aiming to establish agreement criteria for QA practicein RA technique.
Materials: Pre-treatment QA data of the first 100 RA plans performed using aplanar detector (Mapcheck) in combination with a tissue-equivalent phantom(Mapphan) were considered. The patient population was highly inhomogeneous as concern both dose prescription and tumours site mainly including
brain, lung, pancreas, and prostate. Clinical RA plans were optimised anddelivered with 6 MV X-Rays from a Varian Clinac 2300-IX using 2 or 3 arc
depending on treatment complexity.Prior to the use of Mapcheck system inclinical routine its performance for rotational techniques, including angular dependence, was investigated.Pre-clinical verifications were performed by comparing calculated and measured 2D fluencies in terms of g function analysis,
calculated without any dose threshold, using 3%3mm as agreement criteria.
To found uniquely acceptance method, g histogram were analysed by meansof mean values and the percentage of points with g<1, g<1.5 and g>2.
Results: As concern with Mapcheck performance, although large differenceswere detected between calculated and measured field for different gantry
angle (>10% for 90◦ and 270◦ ), the differences highly reduce (generally>1%, rarely > 3%) in a complete rotation through 360◦ , due to compensation effects.Analysis of g function showed the following results (average±SD):gmean=0.4±0.05, g≤1=99%±1.24, g<1.5=99.83%±0.43, g>2=0. Better
results (g<1 greater than 99%) were found for RA plans with lower modulation. Whereas the steep dose gradient and higher dose modulation, usualin the SIB treatment, resulted in a worse g value (g<1 lower than 90% in 17
patients out of 100) and larger deviations between calculated and measured
planar dose (in the worst cases around 4-5%). In this case, using 4%/3mm
criteria, patients with g<1 greater than 90% reduce to 4%.
Conclusions: The use of Mapcheck system for the routine pre-clinicalverifications showed reliable results: although 2D array configuration is
not geometrically ideal for rotational dosimetry, angular dependencies
do not seem to be a limiting factors for routine QA. The system allows
a significant time sparing with respect to conventional radiographic orradiochromic films. Measurements of RA plans generally show a very good
agreement with the calculated ones. Further investigations are aiming to separate RA plans depending on modulation level to properly define the confidence limits of the agreement between expected and measured fluencies fordifferent class solutions.
1333 poster
VMAT WITH MONACO, THE NOVEL TPS: PRESENT STATUS AND
FUTURE APPLICATION
A. Haga1 , A. Sakumi1 , S. Itoh1 , D. Kon2 , S. Kida1 , N. Saotome1 , K.
Ohtomo1 , K. Shiraishi1 , K. Nakagawa1 , Y. Iwai3
1
U NIVERSITY OF TOKYO, Radiology, Tokyo, Japan
2
K AMEDA M EDICAL C ENTER, Radiology, Chiba, Japan
3
E LEKTA KK, Medical Physics, Kobe, Japan
Purpose: In our facility, Volumetric Modulated Arc Therapy (VMAT) has been
employed for over 150 patients of prostate, head and neck, and lung cancers using Monaco v2.03 treatment planning system (TPS) as well as Pinnacle v9.0 SmartArc. Monaco TPS is a next generation planning system with
Monte Carlo dose engines, where both beam weights and MLC segments are
simultaneously optimized based on biological cost functions. We are aiming
at differentiating Monaco TPS from Pinnacle SmartArc at current status.
Materials: First, a single full arc plan for 5 prostate cancer patients and 5lung cancer patients has been created using both TPSs. Dose constrains toorgan at risk for prostate cancer were given to bladder, rectrum, and femoral
heads, while those for lung cancer were given to lung and spinal cord. Effort
was made to maintain the dose volume histograms (DVHs) of organ at risk
almost identical between their plans. These plans were delivered by Elekta
Synergy and the dose verification was performed by using ion chamber andMatriXX with gantry angle sensor (IBA). Second, we directly compared thesame plan by transforming from Pinnacle beam data format to Monaco one,in order to extract dependences of beam modeling and/or algorithm between
Pinnacle and Monaco TPSs in a quality of plan.
Results: SmartArc could optimize the dose constraints. The delivery time forprostate and lung cancer patients using SmartArc plan was 129 sec and 270
sec, respectively, while that using Monaco plan was 219 sec and 410 sec. On
the other hand, Monaco resulted in more accurate dose calculation particularly at low dose regions. That is, a gamma analysis using index of 3% and
3mm with Monaco plan derived the pass rate of more than 99%, in contrast
to SmartArc plan which gave that of about 96%. This means that Monaco
allow more accurate dose optimization for organs at risk. However, Monaco
required much longer calculation time.There are some change in DVHs for organ at risk in comparison using same plan. This difference seemed to affectslightly to the quality of plan.
Conclusions: SmartArc could share the dose for organ at risk and deliver the
homogeneous dose for PTV with rapid delivery. On the other hand, Monaco
TPS provides very accurate dose calculation at low dose regions, which particularly facilitates accurate evaluation of secondary cancer risk in VMAT delivery. We will retrospectively evaluate dose distributions created by SmartArc
VMAT plans.SmartArc could share the dose for organ at risk and deliver the
homogeneous dose for PTV with rapid delivery. On the other hand, Monaco

TPS provides very accurate dose calculation at low dose regions, which particularly facilitates accurate evaluation of secondary cancer risk in VMAT delivery. We will retrospectively evaluate dose distributions created by SmartArc
VMAT plans.
1334 poster
VOLUMETRIC MODULATED ARC RADIOTHERAPY (VMAT) OF
TUMOURS IN THE THORAX - ACUTE TOXICITY RESULTS FROM A
SINGLE CENTRE
M. Ahmed1 , J. Bedford1 , J. Warrington1 , M. Hawkins2
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Sutton, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom
Purpose: VMAT treatment delivery benefits from simultaneous variations ingantry speed, dose-rate and multi-leaf collimator leaf positions. In lung andoesophageal cancer VMAT reduces treatment delivery time and can potentially reduce normal tissue toxicity. Clinical data on this relatively novel radiotherapy technique is lacking. We present acute toxicity data on a cohort ofpatients treated with VMAT.
Materials: Data were collected retrospectively. Patients with carcinoma of thelung (stage I-IIIB) or oesophagus (stage III) were treated radically with VMAT
using a single arc technique. Patients were planned using in-house software
Autobeam version 4.6. No oesophageal or cardiac dose constraints wereapplied in the lung patients. Stage III lung cancer patients received induction
chemotherapy(IC); oesophageal patients received IC and chemoradiotherapy
with capecitabine. Patients were assessed weekly during radiotherapy and at
1 and 3 months for toxicity. Toxicity was graded according to the Common
Toxicity Criteria v3.0. Doses received by the heart, lungs, spinal cord andoesophagus were evaluated. Correlations between dose-volume data andtoxicity scores for pneumonitis and dysphagia were assessed using Spearman’s Rank correlation.
Results: Twenty-eight patients (19 NSCLC, 3 SCLC, 6 Oesophagus) treatedbetween 03.07.08 and 28.06.10 received doses ranging from 50 - 64 Gy. Active Breathing Control (ABC) was used in 11 lung patients. Table 1 reveals
dose volume parameters for lung and oesophagus. Mean lung volumes were4138cc (range 2077 - 8210). Mean spinal cord maximum dose (>1cc) was
29.2 (range 7.8- 46.3). Mean cardiac doses to whole organ and one-third
were 2.3 Gy and 14.5 Gy respectively.Pneumonitis rates were G0 61%, G1
29% G2 7% G3 3%. In lung patients, dysphagia rates were G0 57%, G1
10%, G2 33%. Fatigue was noted in 40% patients (8% G1, 32% G2). Other
toxicities included skin (7%), nausea (7%), thrombocytopenia (3.5%) and depression (3.5%). Three patients did not complete radiotherapy due to development of brain metastases, chemotherapy-related thrombocytopenia andpneumonitis. There was no correlation between lung volume doses and pneumonitis scores at all dose levels. In lung patients dysphagia scores correlated
strongly with oesophagus V35Gy (correlation coefficient = 0.74 p<0.001) but
not with V50Gy or V60Gy. At 3 months there was 1 pneumonitis but all othertoxicities had resolved.

Conclusions: VMAT was extremely well tolerated in this cohort of patients.
Pneumonitis rates were low (≥ G2 = 10%). This may be due to the lungdoses achieved with a combination of VMAT and ABC. Dysphagia rates were
acceptable but an oesophageal dose constraint should be considered.

S 499

Purpose: Volumetric Modulated Arc Therapy (VMAT) that combines dynamic
gantry motion with beam intensity modulation has become clinically available
for planning and delivery of VMAT treatments. In this work, we carry out
assessment of constant dose rate (CDR) - and variable dose rate (VDR)based VMAT planning and delivery methods for lung stereo treatments.
Materials: Ten patients with lung cancer who were previously treated withstereotactic conformal arc technique were selected for this study. Prescription doses to PTVs ranged from 30Gy in 5 fractions to 48Gy in 4 fractions.
Conformal arc (C_ARC) plans consisted of a combination of 6-8 co-planar
static and step-and-shoot IMRT beams. C_ARC plans were generated using
Philips Pinnacle 9.0. Pinnacle’s SmartArc module which supports generationof both CDR -(200 MU/min) and VDR-based (0 through 600 MU/min) plans
was used to generate VMAT plans. For each patient, both VMAT plans consisted of two 180o arcs with 4o arc sampling. The collimator angles of the two
arcs were orthogonal to each other. The same planning objectives for PTVs
and OARs (cord, esophagus, lungs, heart and non-PTV-tissue) were used for
optimization of C_ARC, plans. All plans were compared using MUs, delivery
times and dose-volume parameters for targets and OARs, including conformity index (CI) and homogeneity index (HI) for PTVs, the maximum dose (D2used as a surrogate), D30 and D50 for OARs. For all comparisons, clinicallydelivered C_ARC plans were used as a benchmark. The isodose distributions for each plan were normalized at PTV D98 of the C_ARC plans. The
comparisons between all plans were made relative to the C_ARC techniqueusing a paired two-tailed student’s t-test.
Results: On average, the differences in PTV D2, D50, HI and CI were statistically insignificant, indicating very similar coverage for PTV for C_ARC and
VMAT plans. As far the sparing of OARs, all dose-volume parameters met
the clinical requirements for all sets of plans. Although use of VDR VMAT
reduced cord D2 by 8.3%, it was 2.8% higher with CDR VMAT as compared
to conformal arc stereo plans. The average esophagus D30 was 17% and
19% higher with VDR- and CDR- VMAT respectively although the absolutevalue of the doses was very low. Lung D30 was also 11% and 25% higher
with VDR- and CDR- VMAT compared to the C_ARC plans. The mean MUs
were 1683, 1669, 1880 for C_ARC, VDR- and CDR- VMAT plans respectively
with a 12.7% reduction from CDR- to VDR VMAT. The mean treatment times
were 10.1 min, 9.3 min and 2.8 min for C_ARC, CDR- and VDR- VMAT plans
respectively.
Conclusions: This study showed that both CDR- and VDR-based VMAT
techniques produced similar target coverage that is comparable to that of
C_ARC. Although the critical structure sparing with both VMAT techniques
was generally worse than the ones obtained with the C_ARC, the absolutevalue of the doses to the OARs were very low. In general, the VDR-based
VMAT provided much better treatment efficiency.

IMRT: Treatment planning and optimization

1335 poster

1336 poster

VOLUMETRIC MODULATED INTENSITY MODULATED ARC THERAPY FOR STEREOTACTIC LUNG RADIOTHERAPY: CONSTANTDOSE RATE VERSUS VARIABLE DOSE RATE DELIVERY
N. Dogan1 , Y. Wu1

A COMPARISON OF DOSES TO OARS IN INVERSE PLANNED IMRTAND 3D CONFORMAL PROSTATE TREATMENT PLANNING
B. Mzenda1 , P. Peters1 , J. Pettingell2 , H. Kerr3 , K. Walsh3 , N. Mc Andrew4 ,M. Robb4
1
C ANCER PARTNERS UK LTD., Southampton, United Kingdom
2
C ANCER PARTNERS UK, London, United Kingdom
3
C ANCER PARTNERS UK, Elstree, United Kingdom
4
C ANCER PARTNERS UK LTD., Portsmouth, United Kingdom

1
V IRGINIA C OMMONWEALTH U NIVERSITY, Radiation Oncology, Richmond,
VA, USAS 500

IMRT: T REATMENT PLANNING AND OPTIMIZATIONIMRT: T REATMENT PLANNING AND OPTIMIZATION

Purpose: Following the recent Royal College of Radiologists (RCR) recommendations [1, 2] we treat all our prostate cancer patients with inverse
planned IMRT. This study compares the organ at risk (OAR) doses as wellas the target dose distributions and irradiated volumes in intensity-modulated
radiation therapy (IMRT) and 3D conformal radiotherapy treatment of prostate
carcinoma.
Materials: Twenty patients treated for prostate cancer were planned using
both IMRT and 3D conformal optimisation techniques. The prostate CTV and
PTV were outlined as well as the bladder and rectum. IMRT planning objectives were set as per local protocol to provide 99% dose coverage to the
PTV and to meet the OAR dose constraints. All plans were normalised so themean dose to the PTV was the same for the conformal plan and for the IMRT
plan. The dose constraints used in the treatment planning for the bladderwere V50<50%, V60<25% and V74<5% whilst for the rectum the constraints
were V50<60%, V60<45%, V65<30% and V70<15%. These OAR parameters and resulting DVHs were used for plan comparison. Target coverage was
evaluated in terms of the mean dose and the PTV volume receiving 99% of
the prescribed dose.
Results: The bladder V50, V60 and V74 values, and rectal V50, V60, V65
and V70 values were lower in the IMRT plans compared to 3D conformalplans. Using IMRT resulted in more dose heterogeneity, however lower dose
conformity was observed for the 3D conformal plans. In some cases themean doses were lower for the IMRT plans. The significance of the dose
differences observed was assessed using the statistical paired-t test and thevalues obtained were compared to similar studies [3, 4] and generally good
agreement was found in all cases.
Conclusions: IMRT inverse planning was found to improve OAR sparing aswell as the dose conformity to the PTV. At all our centres the IMRT plan isused to treat patients clinically.The continued follow-up of the patients fromthis study will provide long-term survival data to indicate the significance ofthe reported results.
References
1. Williams MV, Cooper T, Mackay R, Staffurth J, Routsis D, Burnet N,
The Implementation of Intensity-modulated Radiotherapy in the UK,
Clinical Oncology, 22, 2010, 623-628.

of consensus with regards to the number of fields used in a prostate IMRT
plan.
Conclusions: There is a degree of consistency amongst plans with regards
to some aspects of prostate cancer IMRT. However, this consistency is lacking
in other crucial areas. Once centres have had time to implement the ICRU
#83 recommendations, this degree of consensus should improve.
1338 poster
AN AUDIT OF IMRT PTV DOSE DISTRIBUTIONS
D. Bernstein1 , K. Taylor1 , K. Blythe2 , C. Nutting3 , D. P. Dearnaley4
1
R OYAL M ARSDEN H OSPITAL, Joint Department of Physics, London, United
Kingdom2
K ING ’ S C OLLEGE H OSPITAL, Department of Physics, London, United
Kingdom
3
R OYAL M ARSDEN H OSPITAL, Head and Neck Unit, London, United
Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Sutton, United Kingdom
Purpose: To assess the IMRT planning performance at our institution, a review of PTV dose coverage, indicated by dose reporting levels commonlyused in the literature (D99%, D95%, and D5%) and the ICRU 83 recommended dose levels for reporting (D98% and D2%), has been carried out.
Materials: Dose data was extracted from head and neck (H&N) and prostateand pelvic node (PPN) IMRT plans generated during 2006 and 2010. The
plans were generated by various operators using the Varian Eclipse Planningsystem (Version 7.6 in 2006, 8.6 in 2010) with dynamic leaf delivery. Plans
were normalised to the median of the Primary PTV (PTV-p), which had beenedited 5mm from the skin surface to account for dose build up effect. All data
was collected for edited PTVs, with elective Nodal PTV (PTV-n) also edited
to exclude PTV-p. OAR doses were also collected. T-test was used to test forsignificance.

2. Staffurth J (on behalf of the Radiotherapy Development Board), A Review of the Clinical Evidence for Intensity-modulated Radiotherapy,
Clinical Oncology, 22, 2010, 643-657.
3. Luxton G, Hancock SL and Boyer AL, Dosimetry and radiobiologic
model comparison of IMRT and 3D conformal radiotherapy in treatment of carcinoma of the prostate, Int. J. Radiat. Oncol Biol Phys, 59,
2004, 267-284
4. Vlachaki MT, Teslow TN, Amosson C, Uy NW and Ahmad S, IMRT
versus conventional 3DCRT on prostate and normal tissue dosimetry using an endorectal balloon for prostate immobilization, Medical
Dosimetry, 30, 2005, 69-75

1337 poster
A STUDY TO DETERMINE THE DEGREE OF CONSENSUS
AMONGST CENTRES WITH REGARDS TO THE DELIVERY,PRESCRIPTION AND RECORDING OF INTENSITY MODULATEDRADIATION THERAPY IN PROSTATE CANCER IN RELATION TO
ICRU REPORT NO. 83
B. O Miochain1 , M. Broderick1 , M. Coffey1
1
TCD D IVISION OF R ADIATION T HERAPY, Dublin, Ireland Republic ofPurpose: Intensity Modulated Radiation Therapy (IMRT) is an advanced
treatment technique that is very effective at treating multiple cancer sites.
However, inaccuracies can lead to errors and side effects. Therefore, a comparison of IMRT plans can lead to a compilation of effective plans and immobilisation devices. For easy comparison, many values need to be recordedby all centres. The International Commission on Radiation Units and Measurements (ICRU) has recently released a report, ICRU Report no.83, whichcontains many recommendations with regards to values to be recorded from
IMRT plans. The aim of this research project was to analyse the values
recorded from IMRT plans, the immobilisation devices used in these plans
and to determine if these coincide with the new recommendations provided
by ICRU Report no.83.
Materials: A questionnaire regarding the study was distributed to Radiation
Therapists, Radiation Oncologists, Physicists and Nurse Practitioners worldwide
Results: A total response rate of 76 responses was received, consisting ofeight Radiation Therapists, fifty Radiation Oncologists, seventeen Physicists
and one as Nurse Practitioners. It was found that there was a good degree ofconsensus amongst participants regarding immobilisation devices and values
to be recorded from IMRT plans, namely the mean dose and the maximum
dose to Organs at Risk (OARs). There was very little consensus with regards
to the prescription used in centres and the Clinical Tumour Volume (CTV) to
Planning Tumour Volume (PTV) expansions. There was also a good degree

doubling in the number of patients receiving IMRT at our institution. Improvements are seen in PTV-n for H&N only, with mixed results for OARs in bothsites. The changes in plan quality are illustrated using the IRCU 83 recommended D98% and D2%. All PTV tolerances being met suggest that they
could be tightened to force improved PTV coverage and homogeneity.
1339 poster
APPLICATION OF IMRT IN WHOLE-ABDOMEN IRRADIATION OF
OVARIAN CANCER
A. Sladowska1 , J. Pudelek2 , K. Kisielewicz1 , P. Zawadzki1 , M. Waligorski13 ,E. Byrski1
1
C ENTRUM O NKOLOGII -I NST. M. C URIE, Department of Medical Physics,
Krakow, Poland
2
C ENTRUM O NKOLOGII -I NST. M. C URIE, Department of Radiotherapy,
Krakow, Poland
3
I NSTITUTE OF N UCLEAR P HYSICS PAN, Krakow, Poland
Purpose: A preliminary study of technical and dosimetric feasibility ofintensity-modulated radiation therapy (IMRT) of the whole abdomen is reported. Three-dimensional conformal radiotherapy (3D-CRT) and IMRT treatment plans for ovarian carcinoma were compared in terms of reduction ofdose to critical organs and tissues without compromising target coverage.
Materials: Clinical treatment plans using IMRT and three-dimensional conformal radiotherapy (3D-CRT) were prepared for five female patients undergoing chemotherapy of ovarian carcinoma, followed by IMRT. For their evaluation and comparison, treatment plans were designed to adequately treat theplanning target volume and to spare critical organs to the extent possible. The
same planning target volume was used for 3D-CRT and IMRT plans. For eachpatient, a 2-phase 3D-CRT and a 2-phase IMRT plan was prepared. The prescribed dose was 30 Gy in 30 fractions to the whole abdomen (PTV1) in thefirst phase and 20 Gy in 10 fractions to the pelvis (PTV2) in the second phase.
Other structures outlined on the CT images were kidneys, liver, spinal cord,
bladder, rectum, pelvic bones and femurs.Dose distributions were generated
for the following conventional 3D-CRT treatment: anterior-posterior (AP) andposterior-anterior (PA) photon beams in the first phase, and a 4-field "box"configuration for the second phase. Customized blocks were used with AP
and PA fields to cover the kidneys. The liver was blocked in the AP field only.
For both phases of IMRT planning (first phase and pelvic boost), 9 intensity
modulated fields were used. Patients were treated with 18 MV photons using
the sliding window technique. The primary planning objective was to treat
the planning target volume and to minimize dose to the organ at risk (OAR)
structures and to normal tissues.
Results: Dose distribution and dose volume histograms were analysed. With
respect to the PTV1 and PTV2, IMRT planning increased the minimum while
reducing the maximum dose, resulting in improved dose to target conformity.
Against 3DCRT, IMRT plans showed significant reduction of doses to OAR
structures, except for mean dose to kidneys and liver which was higher, but
still within physician-specified clinical criteria. For the same dose constrainsof critical structures, whole-abdomen IMRT showed improved target coverageagainst 3D-CRT.
Conclusions: In whole-abdomen irradiation, IMRT may offer significant advantages compared to 3D-CRT technique. Better target coverage at the samelevel of kidney sparing, and improved sparing of other critical structures are
obtained, due to the concave dose distribution around the target achievable
by application of the IMRT technique.
1340 poster
ASSESSMENT OF AN OPTIMIZATION PARAMETERS DATASET FOR
PROSTATE SIMULTANEOUS INTEGRATED BOOST IMRT
N. Sánchez1 , M. Hermida Lopez1 , J. Maldonado2 , J. Saez1 , X. Fa1 , A.

Results: To date, PTV data from 46 plans generated in 2006 have beencollected (22 H&N and 24 PPN) and 54 plans from 6 months in 2010 (32H&N and 22 PPN). PTV tolerances were always met, with the exceptionof 2 dose level failures in 2010 and 8 in 2006. The table below shows themean and standard deviation of three of the dose levels for PTV-p for bothsites and years. From 2006 to 2010, PPN PTV-p; D99%, D98%, D5% andD2% degraded by between 0.5% and 1.1% of the prescription dose (p<0.05).
For H&N PTV-p, there were no statistically significant differences. PTV-ndoses improved for H&N for D99% and D98% by 1.7% and 0.9% respectively(p<0.05). H&N PTV-n D95% and none of the PPN PTV-n doses showed any
statistically significant differences.For H&N OARs, maximum spinal cord PRV
doses were on average 4Gy lower in 2010, whereas brainstem PRV doses
were on average 2Gy higher. Parotid gland mean doses improved. For PPN
OARS, Bowel doses were generally lower in the 2010 group, whilst rectum,
bladder, and femoral head doses were similar.
Conclusions: This data shows a degredation in PPN PTV-p coverage overtime, with no significant changes in H&N. This is concurrent with a more than

Seoane1 , M. Beltran1
1
H OSPITAL U NIVERSITARIO VALL D ’H EBRON, Physics Department,
Barcelona, Spain
2
H OSPITAL U NIVERSITARIO VALL D ’H EBRON, Radiation Therapy Department, Barcelona, Spain
Purpose: Assessment of a systematic procedure based on proposed initial optimization parameters to create a prostate IMRT treatment plan using
simultaneous integrated boost (SIB) technique. The goal was to establish
a standard in our department for prostate SIB-IMRT treatment planning, toreduce inter-planner dependence and improve dosimetric results. The developed procedure should be considered a tool to obtain a plan close to thedesired result. Plans should be fine-tuned to consider individual patient characteristics.
Materials: In this retrospective study, 23 high-risk prostate cancer patients
who had been previously treated with SIB-IMRT (ORIGINAL plans) were included. These plans were optimized by planners with different levels of experience in IMRT treatment planning. For this study, an initial optimization
parameters dataset was developed based on literature and clinical experience of our department. A new plan (STANDARD) was created according
to the developed dataset, in addition to the original plan (ORIGINAL). BothS 501

plans were calculated (five 6 MV fields) with Varian Eclipse 8.0 treatment
planning system (Pencil Beam Convolution calculation algorithm), with dynamic MLC. Only one optimization cycle was carried out. PTV1 included
prostate and seminal vesicles with 6 mm 3D-margin. PTV2 was obtained
adding 3 mm to prostate. Prescribed doses were 58.5 Gy for PTV1 and 78
Gy for PTV2.Paired samples two-tailed t-tests were carried out to compare
V50, V60, V70 and mean dose for rectum and bladder, maximum dose toposterior rectal wall, D2% to femoral heads and mean dose to remaining volume at risk (RVR), as defined by ICRU-83. PTVs coverage was evaluated.
Monitor units (MU) were also compared.
Results:

Analysis found statistically significant decreases in OAR doses for STANDARD plans: rectum V50 and V60 (-10% and 6%, respectively), rectum
mean dose (-3.2 Gy), bladder V50 (-4.8%), and femoral heads D2% (-3.6
Gy). PTVs coverage was not compromised. Although we found a significant
6% increase in MU for STANDARD plan, mean dose to RVR decreased (p< 0.001). Standard deviations (SD) for V50 in rectum and bladder were significantly reduced. No significant increase in SD was found for any of theanalysed parameters.
Conclusions: Plans created according to the developed procedure allowed
significant reductions in OAR doses, in a systematic way, and without compromising PTVs coverage. Standardized plans also reduced inter-plan variability.
The evaluated optimization parameters dataset was adopted as a standard inour department for prostate SIB-IMRT treatment planning.
1341 poster
COMPARISON OF ORAL CAVITY DOSE BETWEEN DIFFERENTBEAM ARRANGEMENTS OF INTENSITY MODULATED RADIOTHERAPY FOR NASOPHARYNGEAL CARCINOMA
W. C. V. Wu1 , Z. Lin2 , Z. Yang2
1
H ONG KONG P OLYTECHNIC U NIVERSITY, Health Technology Informatics,
Kowloon, Hong Kong, SAR, China
2
S HANTOU U NIVERSITY M EDICAL C OLLEGE, Cancer Hospital, Shantou,
China
Purpose: Radiation induced oral mucositis has been a common side-effectin nasopharyngeal carcinoma (NPC) and adversely affect patients’ quality oflife. Our routine intensity modulated radiotherapy (IMRT) protocol employs 7
beams, in which 5 of them pass through the oral cavity. It is expected that
redirecting more beams away from the oral cavity in planning would reducethe dose to the organ and minimise the radiation complication. This study
compared the oral cavity dose between the routine 7-beam IMRT beam arrangement and two other 7-beam IMRT beam arrangements along with theconventional radiotherapy beam arrangement in the treatment of NPC.
Materials: Ten NPC patients treated by the 7-beam routine IMRT technique(IMRT-7R) between April and June 2009 were recruited. Using the same
CT data, target information and dose constraints for all the contoured structures, two IMRT plans with alternative beam arrangements (IMRT-7M andS 502

IMRT: T REATMENT PLANNING AND OPTIMIZATIONIMRT: T REATMENT PLANNING AND OPTIMIZATION

IMRT-7P) by avoiding the anterior facial beam and one conventional radiotherapy plan (CONRT) were computed using the Pinnacle treatment planningsystem. Dose volume histograms were generated for the planning target volumes (PTVs) and oral cavity from which the dose parameters and the conformity index of the PTV were recorded for dosimetric comparisons among theplans with different beam arrangements.
Results: The doses distributions to the PTVs were similar among the three
IMRT beam arrangements, whereas the differences were significant between
IMRT-7R and CONRT plans. For the oral cavity dose, the three IMRT beamarrangements did not show significant difference. Compared with IMRT-7R,
CONRT plan showed a significantly lower mean dose, V30 and V40, while
the V60 was significantly higher.
Conclusions: The two suggested alternative beam arrangements did not
significantly reduce the oral cavity dose. The impact of varying the beam
angles in IMRT of NPC did not give noticeable effect on the target and oralcavity. Compared with IMRT, the 2-D conventional radiotherapy produced agreater high dose volume in the oral cavity.
1342 poster
COMPARISON OF TWO INVERSE TREATMENT PLANNING SYSTEMS FOR STEP AND SHOOT TREATMENTS
J. M. Perez Moreno1 , D. Zucca1 , P. Fernandez Leton1 , J. García RuizZorrilla1 , A. Minambres1
1
H OSPITAL S ANCHINARRO, Madrid, Spain
Purpose: One of the main problems of IMRT treatments with "Step andShoot" technique is the number of segments and monitor units used in delivery. These parameters are highly dependent on the inverse treatment
planning system which generates delivery sequence of beams and segments.We evaluate two commercial planning systems, making each one aclinical dosimetry for the same series of patients. We compared dosimetricresults, calculated MU and number of segments.
Materials: Two Siemens Oncor Expression accelerators equiped with 160
MLC have been employed (160 leafs 0.5 cm width at the isocenter). These
accelerators have been modeled in two different planning systems: CMS XiO
4.50 and Prowess Panther 5.01.XiO works optimizing fluences of treatment
fields, in order to meet dosimetric criteria set by the user for target volumes
and OARS and auxiliary volumes. Subsequently, it generates a sequence ofsegments to try to get those influences optimized and performs a final calculation with final segmentation. In this steep the user can choose the minimum
size of the desired segment and number of levels of segmentation. This process involves degradation of segmented on the optimized plan. In the other
hand, Prowess Panther is based on direct aperture optimization (DAO). User
specifies how many segments and the desired maximum number of MU foreach field and the TPS optimizes leafs positions and weights of each segment to achieve the dosimetric objectives specified by the user dosimetry.
For comparison we planned in each planning system four cases of head andneck, one rectum case and one case of prostatectomy with lymph nodes. Besides evaluating the dosimetric results, we analyzed the number of segments
and monitor units number of treatment parameters are treated as important
for radiation leakage and treatment delivery time. All optimizations have been
made in accordance with the recommendations of each TPS manufacturer.
Results: Next table summarizes planning results for target volumes and assessment OARs for head and neck cases. Number of segments and totalmonitor units are showed too. Values for mean dose are given in cGy.

Conclusions: Prowess TPS, based in DAO, allows to get dose distributions
with slightly better quality than the other TPS evaluated, XiO. Moreover degradation in the final calculation of the dose is very small, because Prowess directly optimizes MLC positions. On the other hand, the total number of MU
treatment is less than a half and number of segments is much lower, reducing
leakage radiation and treatment delivery times. Time needed for get a planless than in CMS XiO, optimization process is interactive and user can edit
generated segments.Finally, highlight the existence of two unreported cases
in which XiO not reached an acceptable clinical outcome, due to the large

degradation of the dose distribution after segmentation. This is a major problem without a clear anf effective solution in a non-negligible number of cases
to XiO users.
1343 poster
COMPUTER OPTIMIZED NON-COPLANAR BEAM ARRANGEMENTS
IN INTENSITY-MODULATED LIVER SBRT VERSUS VMAT AND
COPLANAR IMRTB. Heijmen1 , I. bin Kassim1 , S. Breedveld1 , P. Voet1 , E. Woudstra1 , A.
Mendez Romero1
E RASMUS M EDICAL C ENTER R OTTERDAM, Rotterdam, Netherlands

1

Purpose: To compare simulataneously optimized non-coplanar beam arrangements and intensity profiles for liver SBRT with VMAT plans and coplanar IMRT. As in our clinical practice, for each of the three approaches, plans
were generated with the maximum achievable tumor dose without violating
imposed hard constraints for tumor coverage and organs at risk (OAR).
Materials: An in house developed algorithm for multi-criterial, integrated
beam angle and intensity optimization, named iCycle [Breedveld et. al.
(2009) PMB 54, pp. 7199; Breedveld et. al. (2009) RO 92, S204], was used
to generate for each of 10 previously treated liver SBRT patients, IMRT plans
with optimized non-coplanar and coplanar beam set-ups with the highest possible tumor dose within the clinical constraints. For each patient, the optimal
coplanar and non-coplanar beam arrangements generated with iCycle werethen imported into our clinical TPS (Monaco, Elekta AB). Next, Monaco plans
with stepwise escalated prescribed doses were generated to establish thehighest possible tumor dose within clinical constraints for both the optimal
coplanar and non-coplanar beam arrangements. For each patient, a similar
procedure was used to generate the VMAT plan with the highest achievable
tumor dose.
Results: For the 10 patients in this study, the mean maximum achievable
tumor dose for IMRT plans with optimized non-coplanar beam set-ups was
118 Gy (range: 60-149 Gy) in three fractions. Compared to coplanar IMRTand VMAT, non-coplanar IMRT yielded on average 25 Gy (range: 4-35 Gy)
and 26 Gy (range: 4-40 Gy) higher tumor doses, respectively.
Conclusions: Compared to VMAT and coplanar IMRT, intensity-modulated
liver SBRT with computer optimized NON-coplanar beam arrangements allowed for large increases in maximum deliverable tumor dose within clinical constraints. Achieved tumor doses were often higher than clinically requested. In those cases, re-normalized plans resulted in much improved OAR
sparing.
1344 poster
CONCOMITANT TREATMENT OF MULTIPLE BRAIN METASTASISWITH WHOLE BRAIN RADIOTHERAPY USING SINGLE ARC VMAT.
A CASE STUDY.
J. Simpson1 , M. T. Khaw1 , A. Falkov1
1
AUCKLAND R ADIATION O NCOLOGY, Auckland, New ZealandPurpose: The addition of stereotactic radiotherapy (SRT) to whole brain radiotherapy has been shown to improve local control and stability of function inpatients with a small number of gross brain metastasis. This approach however requires 2 separate courses of radiotherapy with the SRT course having
multiple isocentres to match the multiple targets. The goal of this study wasto evaluate and utilise VMAT to treat a whole brain whilst simultaneously delivering a boost dose to sites of gross metastatic disease.
Materials: A 53 year old male with primary papillary thyroid carcinoma presented with cerebral metastasis. External beam radiotherapy was prescribedto deliver a tumouricidal equivalent dose of 36Gy in 20 fractions to the wholebrain and a boost dose of 50.4Gy in 28 fractions to 3 sites of gross metastatic
involvement (parietal, ventricular and C2 spine). Both prescriptions wereplanned as a simultaneous treatment over 28 fractions with the equivalent
whole brain dose prescription of 37.5Gy (α/β =10). A single isocentre 360 degree arc VMAT treatment plan was developed using Pinnacle-3 and SmartArc
for subsequent treatment on an Elekta Synergy linac using 6MV photons.
Treatment delivery time was 120 seconds. Structure sparing limits were applied to the chiasm and optic nerves 50.4Gy, cochlea 45Gy and parotid 30Gy.
Results: The homogeneity index (max dose/prescription dose) was 1.45 forthe brain excluding boost volumes and 1.01, 1.05 & 1.05 for the C2-spine,parietal and ventricular boost volumes respectively. The conformity index(prescription volume/target volume) was 1.19 for the brain excluding boost
volumes and 1.12 for the combined boost volumes. Dose constraints to
the risk structures were all met. Treatment delivery was QA’d using an Iba
Dosimetry MatriXX ion chamber array and absolute isocentre dose measurement. A gamma index pass of 97% with a 3%, 3mm tolerance was achieved
with an isocentre dose deviation of 1.5%.
Conclusions: A single isocentre single arc VMAT plan was shown to meet
all the prescription objectives and was thus able to deliver a highly conformal
dose distribution with good normal structure sparing as an efficient single arctreatment.

1345 poster
DOSIMETRIC AND BIOLOGICAL IMPACT OF DIFFERENT METHODSOF IMRT PRESCRIPTION FOR NASOPHARYNGEAL CANCER
S. Kumar1 , P. Vial23 , A. Wallis1 , Y. Griffiths4 , L. C. Holloway234
1
L IVERPOOL AND M ACARTHUR C ANCER T HERAPY C ENTRES, Departmentof Radiation Oncology, Sydney, Australia
2
L IVERPOOL AND M ACARTHUR C ANCER T HERAPY C ENTRES, Departmentof Medical Physics, Sydney, Australia
3
I NSTITUTE OF M EDICAL P HYSICS , U NIVERSITY OF S YDNEY, Sydney,
Australia
4
C ENTRE FOR M EDICAL R ADIATION P HYSICS , U NIVERSITY OF W OLLON GONG , Wollongong, Australia
Purpose: While IMRT is now routine treatment for many tumour sites, there
is a lack of consistency in dose prescribing standards. Clinical trial protocols from RTOG and EORTC, and recommendations in ICRU report 83, have
replaced prescribing to the ICRU reference point by various volume based
methods for IMRT. The ICRU 83 report recommends keeping the target doselevels constant when changing from one prescription method to another. The
clinical impact of using different prescribing methods remains unclear. This
study evaluated the dosimetric and biological impact of using different volumetric prescribing methods for nasopharyngeal cancer (NPC) IMRT.
Materials: Three patients treated for NPC with three prescription dose levels(70Gy, 59.4Gy and 54Gy in 33 fractions) were selected retrospectively. For
each patient a plan was generated first using a prescription aim of D95 (prescribing the TD for each volume to the 95% isodose line based on RTOG trial
0615 criteria) and then the plans were reoptimised to achieve the prescription aim of D50 (prescribing the TD for each volume to the 50% isodose line
based on ICRU 83). Planning was stopped once dose volume criteria or selected normal tissue constraint was reached. Each plan had nine beams andthe angles were kept constant between plans. To achieve endpoint for eachprescription method, the dose objectives were changed during optimisation.
Equivalent uniform dose (EUD) was used for plan comparison.
Results: Achieving the planning aims for both prescription methods was difficult due to proximity of critical structures. This effect was more exaggerated
with patient 1 whose PTV59.4 and PTV54 were at the level of lens. This iscan be seen in the EUD values in table 1 below where the modelled EUD
is significantly lower. Table 1 illustrates the magnitude of change required to
the D50 prescription plan to maintain the same EUD as D95. No significant
difference was noted in the dose to critical structures between prescription
methods.
Conclusions: This study illustrates the potential clinical impact when changing between prescription methods. Changing from D95 to D50 without correcting the dose levels resulted in reduced dose coverage and EUD, to thetarget volumes. This effect was exemplified in patient 1 due to heterogeneous dose distribution as a result of proximity to critical structures. This
study demonstrates the need for considering (i) dose level changes whenchanging prescription methods, and (ii) patient-to-patient variations when applying such dose corrections. Further work is required to better understandthe potential clinical impact when changing prescribing methods.

1346 poster
DOSIMETRIC COMPARISON OF DIRECTIONAL, COMPLETE
AND NO BLOCK IN TOMOTHERAPY FOR WHOLE LEFT BREAST
IRRADIATION
F. K. F. Cheng1 , G. Chiu1 , A. Mui1
1

H ONG KONG S ANATORIUM & H OSPITAL, Department of Radiotherapy,
Happy Valley, Hong Kong (SAR) China
Purpose: To evaluate the dosimetric effect of directional block and complete
block application in whole left breast irradiation in tomotherapy planning.
Materials: Thirteen patients with left breast cancer were recruited. Planning target volume (PTV) was defined by oncologist. Normal tissue including
heart, lungs, spinal cord and right breast were contoured. For each patient,
three tomotherapy plans were created: 1. Without block (Plans-A). 2. Using
directional block for all mentioned normal tissue (Plans-B). 3. Using complete
block for right breast and right lung, and directional block for all other normal
tissue (Plans-C). All the plans had 95% volume of PTV receiving 50Gy. Sameinitial optimization parameters were used and the parameters were adjusted

S 503

by same extent after same optimization iterations in all the plans for all patients to attain fair comparison. Homogeneity index (HI), conformity index (CI)and dose-volume histograms were compared among the plans.
Results: The mean HI of Plans-B (7.09%) was superior to Plans-A (9.45%)
and Plans-C (15.55%). The mean CI was comparable in Plans-A (84.29%)
and Plans-B (84.46%) but lower in Plans-C (80.44%). Both mean left lungvolume percentage and mean heart volume percentage receiving 20Gy was
lower in Plans-B (14.03%, 11.06%) compared with Plans-A (15.88%, 15.49%)
and Plans-C (17.29%, 17.5%). However, Plans-C had lower right lung doseand right breast dose. There were no right lung and right breast tissue receiving 10Gy in Plans-C, while the mean right lung volume percentage and meanright breast volume percentage receiving 10Gy in Plans-A and Plans-B were
(21.82%, 7.92%) and (11.82%, 3.39%) respectively.
Conclusions: Plans-B provides better target dose homogeneity and conformity and it has better sparing of normal tissue compare with Plans-A. Plans-C
can achieve better tissue sparing of right lung and right breast, however it isinferior in HI and CI comparison. Application of directional block to heart,lungs, spinal cord and right breast is recommended in whole left breast tomotherapy planning.
1347 poster
DOSIMETRIC CONSIDERATIONS FOR SPINAL SINGLE FRACTIONINTENSITY MODULATED STEREOTACTIC RADIOSURGERY WITH
BRAINLAB NOVALIS
D. Zucca Aparicio1 , J. M. Perez Moreno1 , P. Fernandez-Leton1 , J. García
Ruiz-Zorrilla1 , A. Minambres1
1
H OSPITAL U NIVERSITARIO M ADRID S ANCHINARRO - G RUPO H OSPITAL DE
M ADRID, Servicio de Radiofísica y Protección Radiológica, Madrid, Spain
Purpose: Spinal Radiosurgery is often performed with Intensity Modulated
Stereotactic Radiosurgery (IMRS) so availability of a class solution should be
useful for routine planning of this kind of treatments.
Materials: BrainLAB iPlan RT Dose 4.1.2. (Feldkirschen, Germany) TPS
has been used for implementation of a class solution for spinal metastasis treatments based on 9 equal spaced coplanar IMRS beams (dynamic
leaf sequencing) and considering IMRT optimization parameters such as 3
mm beamlet size max with adaptive dose grid size for small objects andtongue&groove optimization of segments.For ensuring dose fall-off outside
PTV, Normal Tissue Restriction have been taken into account by consideringa maximum dose around 5 mm from PTV of 16 Gy (dose prescription to PTV
are such as 18 Gy covers 100% of volume) RTOG 0631 guidelines have been
followed for the evaluation of the dose coverage for the PTV and HDV constraints for involved OAR.IMRT verifications with radiochromic film have been
performed for each complete treatment by gamma analysis for axial planemeasures by rescaling dose prescribed to be inside the optimal dose range
from the calibration curve. Also bidimensional calibrated ion chambers array(PTW 2D array seven29) placed inside IMRT Phantom (PTW Octavius) measures have been analyzed for coronal plane gamma comparison and absolutedose distribution evaluation.
Results: From November 2008 to April 2010 we have treated 9 patients withvertebral metastasis, medium age 56 years [46-72], all the patients received
single fraction of 18 Gy to the entire body of the vertebra and the affectedtransverse and spinous processes. The location of the vertebral metastasis
was: cervical spine 2, thoracic spine 5, lumbar spine 2; none of the patients
have had prior radiotherapy on the treatment site.The mean PTV volume was
51 cm3 [30-95]. Dose coverage was evaluated to ensure at least 90% of
target volume was covered by 16 Gy and 95% of prescription dose covered
95% of PTV. All the cases analyzed accomplished the most important dose
constraint of 10 Gy to the 10% of the partial spinal cord volume defined as 6mm above and below the target.Gamma analysis (3% difference dose - 3 mm
DTA) for Gafchromic EBT and Gafchromic EBT2 evaluated over a wide ROI
around PTV cross section presents an agreement over 97.4% [mean 99.3%]
for all the comparisons and for the complete film analysis over 92.1% [mean95.7%]
Conclusions: A class solution has been provided to formalize Spinal Radiosurgery IMRT optimization and accomplish the recommendations included in
RTOG 0631. In addition, IMRT quality assurance verification are needed dueto the high doses involved in target volume very close to critical structures or
embedded inside PTV
1348 poster
EFFECTS OF BEAM WEIGHT POINT LOCALIZATION ON HEAD AND
NECK INTENSITY MODULATED RADIOTHERAPY PLANS
H. Bas1 , C. Ceylan1 , A. Kilic1 , N. Kucuk1 , M. Guden1 , K. Engin1
1
A NADOLU S AGLIK M ERKEZI, Radiaotherapy and Oncology, Gebze /Kocaeli, Turkey

Purpose: Head and neck cancers are well suited for IMRT because of highdose to their concave shaped CTVs for better local control and critical structures around the CTV that should be protected to reduce side effect. IMRT
fields can be highly modulated due to the large number of degrees of freedom

S 504

IMRT: T REATMENT PLANNING AND OPTIMIZATIONIMRT: T REATMENT PLANNING AND OPTIMIZATION

such as intensity level and weight points of beams. In this study we focusedon effect of beams’ weight point localization of IMRT head and neck patientsto achieve improved dose distribution.
Materials: Patients with larynx and nasopharynx cancer who were previously
treated with IMRT in our clinic were included in this study. Seven beams were
sufficient to create highly conformal dose distribution within the Gross Tumor
Volume (GTV) and sparing critical organs such as parotids. Two inverse IMRT
plans were calculated changing localization of weight point of beams while
keeping other inverse planning optimization parameters are same for bothplans. Initially, IMRT plans were calculated at the isocenter and weight pointsof beams at the same coordinates which is center of Planning Target Volume(PTV). Secondly, IMRT plans were calculated by only changing weight pointof beams from isocenter to center of primary tumor clinical target volumes
such as nasophaynx Clinical Target Volume including GTV and suspectedarea around GTV. A commercial IMRT treatment planning system (CMS XiO
St.Louis) was used to provide IMRT treatment plans using conventional multileaf collimators (MLCs). Seven gantry angles at 00 , 510 , 1020 , 1530 , 2040 ,2550 and 3060 and 6 MV energy were selected. After optimization, segmentsof each individual beam were created using same intensity level. Comparison of two plans for each patient was done using Dose Volume Histograms(DVH), segment numbers and Monitor Units (MU) of segments.
Results: DVHs’ of two IMRT plans were compared in terms of coverage oftarget volumes and critical organ doses such as parotid glands and spinal
cord. Although second plan which have weight point of beams localized at thecenter of CTV of primary tumor represents better target coverage than firstplan which have weight point of beams at the center of PTV, critical structure
sparing was found slightly better at the first plan. Without making any changes
at the intensity level of beams for both plans, smaller segment number and
MUs were obtained at the first plans.
Conclusions: The number of beams, the beam orientations and the number of segments are important parameters for the optimization process of an
IMRT plans. We studied that effect of weight point of IMRT beams should be
optimized for head and neck patients’ IMRT plans. We found that optimum
IMRT plans for head and neck cases can be achieved if the weight point ofbeams localized at the center of primary clinical tumor volume. These results
could be implemented IMRT in routine clinical practice.
1349 poster
IMPLEMENTATION OF INTENSITY MODULATED RADIATIONTHERAPY FOR PARTIAL BRAIN IRRADIATION
J. van Santvoort1 , M. Eenink1 , A. Petoukhova1 , R. Wiggenraad1
1
R ADIOTHERAPY C ENTRE W EST, The Hague, Netherlands
Purpose: Radiotherapy treatment planning for gliomas is often difficult because of the vicinity or even overlap of the PTV with organs at risk (OAR)
such as the optical system and brainstem. Because of considerable variation of tumor position between patients, development of a standardized classsolution is unfeasible. We have therefore developed a flexible IMRT technique that gives the planner the possibility to easily adjust planning priorities
between PTV and OAR to arrive at a clinically acceptable solution.For eightpatients both 3D conformal plans (CRT) and IMRT plans have been madeand the results of the two techniques are compared.
Materials: After delineating the PTV and OAR, the radiation oncologist formulates guidelines regarding PTV coverage and OAR sparing. To meet theseguidelines, auxiliary structures are defined which are used by the treatment
planner to tune the IMRT optimization. First, an auxiliary ring structure is defined around the PTV. A sharp dose gradient around the PTV is realized by
employing a maximum equivalent uniform dose objective in this ring. Second, the OARs are each split into two auxiliary structures by subtracting the
PTV and the previously defined ring structure from the OAR. By employing
separate maximum dose objectives on the two auxiliary structures (overlapping and non-overlapping), dose in each individual OAR can be fine-tuned
between optimal PTV coverage and maximum OAR sparing.Because generating the auxiliary structures manually is time-consuming, plan setup wascompletely automated. To this end, the scripting possibilities of the Pinnacle3
treatment planning system (Philips) were employed, combined with Python
scripting.IMRT and CRT plans have been compared regarding PTV coverage, maximum dose to critical structures and normal brain dose.
Results: The result is a versatile IMRT technique that gives the planner flexibility to steer the dose distribution in the right direction. Because of the automated plan setup, less time is spent on treatment planning than with CRT.
Moreover, resulting plans require on average only half of the monitor units
that are used for CRT. IMRT plans show improvement of PTV coverage andconformality compared to CRT plans, with similar doses to OARs and normal
brain, although results vary widely between patients. With IMRT it is easierto fulfill individual OAR constraints, if necessary at the cost of a somewhat
higher dose to another OAR that is well below its constraint.
Conclusions: The developed IMRT technique has been successfully implemented clinically, and since then applied to about 40 patients.

1350 poster
INTEGRAL DOSE IN RAPID ARC OPTIMIZATION USING MUOBJECTIVE: A PRELIMINARY STUDY
M. Cozzolino1 , C. Stefania1 , R. Caivano1 , G. Califano1 , P. Pedicini1 , C.
Chiumento1 , F. Alba1 , A. M. Mileo1 , V. Fusco1
1
IRCCS CROB, Radiotherapy, Rionero in Vulture, Italy
Purpose: A preliminary study to evaluate the effect of using the "MU objective" tool in the optimization of RA plans.
Materials: Currently, we presented the results of four patients treated forprostate cancer randomly selected. Plans were re-computed with Rapid Arc
techniques for the study. CTV was defined as prostate and the proximal 2 cmof the seminal vesicles were included if the risk of seminal vesicle involvement
was assessed to be more than 10% or if clinical tests or biopsy showed seminal vesicle involvement. PTV was CTV plus 7 mm margin in the cranio-caudal
direction and 5 mm in other directions.The prescribed dose to PTV was 74 Gy.
RA techniques were optimized for each patient with the AAA-based commercial planning system Eclipse 8.6. The plans consisted of one full arc, counterclockwise from 179.9◦ to 180.1◦ . The collimator angle was chosen at 0◦ .The
aim of this study is to evaluate the integral dose to OARs, normal tissue andwhole body in regard of the MU objective. The MU objective tool controls thenumber of MUs to keep the MUs for the plan low. Three parameters werechanged: maximum MU (MaxMU), minimum MU (MinMU) and strength (S)of MU objective. We compared four plans for each patient: i) in the first optimization (1) the MU objective tool wasn’t used. The MUs supplied by thisplan were indicated with MU(1). ii) The second optimization (2) used MU
objective setting S=50, MinMU=0 and MaxMU=MU(1)-100, iii) The third (3)used S=100, MinMU=0 and MaxMU=MU(1)-100. iv) In the last (4) optimization the parameters chosen were S=100, MinMU=0 and MaxMU=MU(1)-200.
Dose prescription/plan normalization was identical for all approaches. The
DHV of plans were compared for dose homogeneity to PTV (homogeneity index=D5%/D95%) and integral doses ID (ID=Dmeanvolume) to OARs, normal
tissue (defined as Body-PTV) and the whole body (defined as entire volumeof all slices where PTV existed). The value of constraints for OARs were:
for the rectum V50<50%, V60<40%, V70<25%; for the bladder V60<35%, forthe femoral head mean dose<45Gy; for the penile bulb mean dose<50Gy,
D90<50Gy and D60-70<70Gy.
Results: The MUs obtained respectively by the (2), (3) and (4) optimizations
decrease of 6.6%, 18.6%, 29% compared to the optimization without MUs
objective tool (1). A summary of integral doses to OARs, normal tissue andwhole body was reported in tab.1. The maximum difference in integral dose
to OARs was 23% respect of the optimization without MU objective tool. The
constraints for OARs were always preserved for all plans. The homogeneity
index was 1.08 for all RA plans. The maximum decrease of ID to normal
tissue was 0.6%, and the maximum decrease of ID to whole body was 0.5%.

Conclusions: The MU objective reduced the integral dose to OARs, preserving the constraints and dose homogeneity to PTV. No significant difference tointegral doses was found for normal tissue and whole body.
1351 poster
NOVEL SIMULTANEOUS INTEGRATED SPARING VMAT TECHNIQUE
FOR CRANIOSPINAL RE-IRRADIATION
M. Kusters1 , P. van Kollenburg1 , R. Louwe1 , M. Kunze-Busch1 , C. Gidding2 ,E. van Lindert3 , J. Kaanders1 , G. O. Janssens1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Department ofRadiation Oncology, Nijmegen, Netherlands
2
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Department ofPediatric Oncology, Nijmegen, Netherlands
3
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Department of
Neurosurgery, Nijmegen, Netherlands
1

Purpose: The majority of patients with standard-risk medulloblastoma will be
cured after tumor debulking, craniospinal irradiation with boost to the tumor
bed and adjuvant chemotherapy. Patients who develop leptomeningeal recurrences have an extremely poor prognosis despite aggressive chemotherapy with or without focal re-irradiation. The aim of this study is to develop atechnique for craniospinal re-irradiation in patients with leptomeningeal failure
without evidence of posterior fossa tumor bed recurrence, using a volumetricmodulated arc therapy (VMAT) with Simultaneous Integrated Sparing (SIS) of
the previous high dose region.
Materials: A patient developed a lumbo-sacral leptomeningeal recurrence after 23.4/1.8 Gy on the craniospinal axis (PTV1>) followed by a posterior fossa
tumor bed boost up to 54/1.8 Gy (PTV1<) was given 2 years before (Fig. A).
In this original treatment a broad dose gradient region ranging from 23.4 to51.3 Gy around the boost volume (PTV1<) is present due to the sequential
treatment set-up. For the craniospinal axis re-irradiation including the SIS approach, the new SmartArc module of Pinnacle v 9.0 (Philips Medical System,
Madison, WI) was used. A maximal total EQD2 (α/β =2) of 45 and 54 Gyon the whole craniospinal axis and fossa posterior, respectively was allowed.
A recovery of 30% and 50% in the PTV1<- and PTV1>-areas, respectively
was assumed. Based on EQD2 calculations applied to the dose region from
23.4 to 51.3 Gy in the initial treatment plan, an inverse dose gradient in thesame region (PTVHDG) ranging from 35 to 51.3 Gy was created to preventa possible overdosage in the posterior fossa. Based on these calculations aplan was prescribed with a total dose of 32/1.6 Gy on the craniospinal axis
(PTV2>) with SIS for the tumor bed (PTV2<) down to 24/1.2 Gy and a biologically corrected dose gradient from 24 Gy to 32 within PTVHDG. A sequential
boost dose of 9.0/1.8 Gy was planned for the macroscopic lesions.
Results: Fig. B shows that the re-irradiation of the craniospinal axis using
VMAT with SIS results in a good coverage of all PTVs and a good dose homogeneity within PTV2< and PTV2> (minus PTVHDG). In addition, the dose
gradient from 24 to 32 Gy in PTVHDG to compensate for the overdosage inthe original treatment closely follows the a priori desired biological dose gradient. For the PTVs of the tumor bed (PTV2<) and PTV2> (minus PTVHDG),
the V95 was 100% and 96% with a mean dose of 24.7 Gy and 32.2 Gy, respectively. The V>107 was less than 1% in both PTVs and the homogeneity
index was 0 for PTV2<.

S 505

Purpose: To date, Radiotherapy Centers have to sort patients between the
different linacs available in their Departments. The purpose of this work is toevaluate the performance of three differents linacs with different characteristics of the MLC collimator in term of number and width of leaves implemented
to perform Intensity Modulated Radiation Therapy (IMRT).
Materials: Siemens Artiste, Varian DHX and Siemens Oncor have multileaf
collimators with different characteristics: the first has 160 multileaf collimatoreach of 0.5-cm width, the second has120 leaves 0.5-cm width and the third 80
leaves 1-cm width. Treatment planning were performed with these machines
for different cancer patients, including head and neck, prostate, rectal cancer,
lung, pelvis; segmental multileaf collimator step and shoot IMRT plans were
performed with Phillips Pinnacle 3 Treatment Planning System (TPS). The
plan optimization was based on dose volume constraints adopted in clinicalpractice for planning target volumes (PTVs) and organ at risks (OARs); allplans are optimized with the same beam arrangement and beams segmentation to reach equivalent target coverage. Dose volume histograms, maximum, minimum and means dose, coverage, homogeneity and conformity
index were used in the comparison of the PTVs; the respect of constraints
are used for evaluation of OARs.
Results: The use of the three accelerators seems to be equivalent for treatment of large treatment volumes, such as pelvis. For rectal and prostate morebeams and more segmentation are needed to achieve the same results. For
the treatment of head and neck the 160 MLC collimator reduced hotspots
within the PTVs and showed improvement of critical structure avoidance, inparticular for the adjacent parotid glands. For lung cancer the performances
seem to be strongly affected by volume and position of the lesion.
Conclusions: Efficiently organization of Radiotherapy departments needs anaccurate evaluation of the performance of the Linacs available in particular interms of the capacity to high dose gradients and accurate delivery.
1353 poster
PLAN QUALITY AND PERIPHERAL DOSE IN ARTISTE IMRTTREATMENTS: COMPARISON WITH CLINAC120MILLENNIUM AND
TOMOTHERAPY
P. Grimaldi1 , D. Aragno1 , R. Argentini1 , M. Betti2 , C. Caruso3 , V. Donato3 ,L. Orlandini2 , M. C. Pressello1 , R. Rauco1 , E. Santini1
1
A ZIENDA O SPEDALIERA S AN C AMILLO - F ORLANINI, Medical Physics
Department , Roma, Italy
2
C ENTRO O NCOLOGICO TOSCANO, Medical Physics Department, Florence,
Italy
3
A ZIENDA O SPEDALIERA S AN C AMILLO - F ORLANINI, Radiotherapy
Department, Roma, Italy

Conclusions: The current concept of VMAT with SIS demonstrates the feasibility of delivering salvage high-dose re-irradiation to the craniospinal axis
while sparing high dose regions in the initial treatment. However, because of
potential toxicities, implementation can only be performed within the context
of a well-designed clinical trial.
1352 poster
OPTIMIZATION OF CLINICAL DELIVERY OF IMRT TREATMENTPLANNING WITH LINACS HAVING DIFFERENT PERFORMANCE OF
MULTILEAF COLLIMATOR
L. C. Orlandini1 , M. Betti1 , M. De Liguoro2 , M. C. Pressello3 , L. Strigari4 , C.
Luca2
1
C ENTRO O NCOLOGICO F IORENTINO, Fisica Sanitaria, Firenze, Italy
2
C ENTRO O NCOLOGICO F IORENTINO, Department of Radiation Oncology,
Firenze, Italy
3
O SPEDALE S. C AMILLO - F ORLANINI, Fisica Sanitaria, Roma, Italy
4
I STITUTO R EGINA E LENA - IFO, Laboratory of Medical Physics and Expert
Systems, Roma, Italy

Purpose: New modalities of RT delivery have been demonstrated able toprovide better target coverage and OARs sparing. On the other hand, clinical follow up of patients undergone to IMRT seems to show an increase insecondary cancer incidence respect to those treated with 3D-CRT probably related with the raise of peripheral dose (PD), i.e. the exposure of theout-of-field healthy tissues (HT), associated to IMRT treatments [Hall 2003].
The main source of this undesired exposure has to be ascribed to Linac
head and, above all, to MLC characteristics. This problem was addressedin the design of the new Siemens Linac Artiste (ART160). In fact, the 160
leaves, 5 mm wide at isocenter, are slightly tilted off the ray-trace from thebeam source, greatly reducing inter-leaf transmission. Moreover, thanks to
the large leaf thickness, the leakage of the 160 MLC™is smaller compared tothe other MLC designs (Bayouth2008,Tacke2008). The aim of this work is toevaluate the ART160 performance in IMRT treatments in term of plan quality
and PD reduction. The study will be carried out in comparison with a Varian
Clinac mounting 120MLC Millennium (VCM120) and with Tomotherapy HiArt(TTHA).
Materials: Five gynecological cancer patients were planned for IMRT treatments with the three accelerators. Prescribed dose to PTV1 (including
lymph nodes) and to PTV2 (primary tumor boost) were 50Gy and 60Gy in
30 fractions, respectively. VCM120 and ART160 plans were optimized with
Pinnacle3 8.0m (seven coplanar 6MV beams, DMPO optimization algorithm).
TTHA plans were planned with pitch 0.287, beam width 2.5 cm, and MA of
2.5. Plan quality assessment were performed with an in-house software: criteria for plan comparison will be conformity index [Batlas 1998] and uniformity
S-index [Yoon 2007] for target coverage and Dmean and Dmax for OARs
sparing. The integral dose ID (D’Souza 2003) was calculated to evaluate infield HT exposure, whereas to evaluate PD variations the 5 and 2 Gy isodose
volumes were compared. The overall treatment time and the total MU number
were also registered for the three delivery techniques.
Results: PTV coverage was between 95% and 105% of prescribed dose forall techniques, with comparable conformality and uniformity in dose distributions achieved with VCM120, ART160 and TTHA plans. Dose-volume constraints for OARs were satisfactorily accomplished for all the techniques, withslightly better results for TTHA. An In-field ID decrease of about 5% in TTHA
plans respect to conventional Linacs was observed. Concerning PD, TTHA
dose distributions showed an increase of about 5% of volumes exposed to
low doses respect to ART160.
Conclusions: Siemens ART160 plan quality in IMRT treatments is comparable to the best in class competitors, superimposing TTHA and VCM120
performances. Moreover, a lower PD was detected for ART160 plans respect

S 506

IMRT: T REATMENT VERIFICATION AND QA

IMRT: T REATMENT PLANNING AND OPTIMIZATION
Conclusions: 2-Step Fast IMRT allows reduction of the segment number
and the delivery time by increasing the beam number and implementing information of the analysis of the topology of PTV and OAR.

to TTHA.
1354 poster
POTENTIAL ADVANTAGES AND TRADEOFFS OF INTENSITY MODULATED RADIOTHERAPY FOR LOCALLY ADVANCED PANCREAS
CANCER (INCLUDING ELECTIVE NODAL VOLUMES)
C. Eccles1 , K. A. Vallis1 , W. McKenna1 , T. Brunner1
1
G RAY I NSTITUTE FOR R ADIATION O NCOLOGY AND B IOLOGY, Radiation
Oncology and Biology, Oxford, United Kingdom
Purpose: Intensity modulated radiotherapy (IMRT) has proven beneficial intreatment of locally advanced pancreatic cancers (LAPC) with and without
regional lymph nodes. However its benefit in pancreatic radiotherapy (RT) including elective nodal volumes is not well documented. We have investigatedthe effects of IMRT on normal tissue tolerance with the goal of reducing doselimiting toxicity in the organs at risk (OARs).
Materials: The first six patients accrued to an ethics approved phase II studyof chemoradiation plus the AKT inhibitor Nelfinavir, for LAPC (ARC-II) weretreated with forward-planned conformal RT. A dose of 50.4 Gy /28 fractions
was prescribed to the tumour and elective nodal volumes (PTV50) followed
by a boost of 9 Gy /5 fractions to the tumour plus a margin (PTV59). PlanningCTs for all patients were used IMRT re-planning, first with the same beamarrangements as the conformal plans (IMRTA) and then a previously reported
beam arrangement for pancreatic IMRT (IMRTB)(1). A biologically equivalentdose was determined so that an integrated boost could be used such that
PTV50 became PTV52 (delivered in 33 fractions), and PTV59 remained thesame. All plans were optimised using ARC-II dose constraints of a minimum(min) 95% target dose to 99% of the PTV, and maximum (max) doses of 40
Gy to the cord, 20 Gy to 30% of the ipsilateral and 50% of the contralateralkidney, and 30 Gy to 50% of the liver. Once these parameters were met,
further optimization was performed to reduce duodenum, stomach and small
bowel doses.
Results: Forward plans used 6 and/or 15 MV, 4-6 beam angles and up to twosegments/beam. IMRTB was a non-coplanar beam arrangement with four
beams at 0 and two at 90 floor rotations. All IMRT plans used 6 MV. Whilemaintaining equivalent target coverage IMRT reduced at minimum one OAR
dose compared to the CRT plan. IMRTB showed statistically significant reductions (p<0.05) in the liver (D30) and ipsilateral kidney (D50) of 32 and 24%
respectively. Both IMRTA and B demonstrated reductions in mean duodenal
and stomach (D30) doses in 5/6 patients. Stomach D30 was reduced by 11
and 18%, corresponding with max reductions of 9.6 and 16Gy in IMRTA and
B respectively. Mean duodenal doses were reduced in 5/6 patients by 1.4 and
3.0%. Tradeoffs included increases in max cord doses in 4/6 IMRTA and 3/6
IMRTB plans. Integral doses (body-PTV) were reduced by >15Gy in a single
patient and on average by 8 and 12% over all patients in IMRTA and B.
Conclusions: Conclusions: IMRT using a biologically equivalent boost may
reduce normal tissue doses in LAPC RT to volumes including elective nodal
volumes. This is crucial for the safety of early phase trials with novel agents.
Further investigations into the most appropriate beam arrangements as wellas the incorporation of functional imaging for target delineation are currently
on-going.
1. Ben-Josef E, Shields AF, Vaishampayan U, et al. Int J Radiat Oncol Biol
Phys 2004;59:454-459.

1356 poster
REDUCTION OF RADIATION-INDUCED SWALLOWING DYSFUNCTION BY SWALLOWING-SPARING IMRT: A PLANNING
COMPARATIVE STUDY
C. Schilstra1 , H. P. van der Laan1 , M. Christianen1 , H. P. Bijl1 , H.
Langendijk1
1
U NIVERSITY M EDICAL C ENTER G RONINGEN / U NIVERSITY OF G RONIN GEN , Department of Radiation Oncology, Groningen, Netherlands
Purpose: To investigate the potential benefit of swallowing-sparing intensity modulated radiotherapy (sw-IMRT) reference to parotid-sparing standard
IMRT (st-IMRT), based on recently developed predictive models for radiationinduced dysphagia.
Materials: Thirty head and neck cancer patients that underwent radiotherapy
including both necks were randomly selected for this in-silico planning comparative study. For each patient st-IMRT and sw-IMRT treatment plans werecreated. For all plans, the prescribed dose to the boost planning target volume (PTV) was 70 Gy in 2 Gy fractions and 54 Gy to the elective nodal PTV
in 1.54 Gy fractions, using a simultaneous integrated boost technique. StIMRT treatment plan optimization aimed at obtaining adequate target volume
coverage (i.e. ≥ 98% of volume receives ≥ 95% of prescribed dose and ≤2% of volume receives > 107% of 70 Gy), while limiting the dose to the spinal
cord and brainstem, and sparing the parotid glands as much as possible. SwIMRT optimization specifically aimed to spare the swallowing-related organs
at risk (SWOARs), additional to the objectives for st-IMRT. For all plans, theprobability of radiation-induced dysphagia was calculated with recently developed predictive models. One of the models predicted the probability ofRadiation Therapy Oncology Group (RTOG) grade 2-4 physician-rated dysphagia. The others predicted the probability of patient-rated moderate to severe complaints as defined on the EORTC QLQ-H&N35 scale, with regard
to the swallowing of solid food, soft food, liquid food, and aspiration, all at 6
months after RT.
Results: All plans showed adequate target volume coverage, while the doseto critical organs was within accepted limits. Sparing of the parotid glands
was similar for st-IMRT and sw-IMRT. With sw-IMRT, the mean dose to thevarious SWOARs was significantly reduced. Absolute dose values and dose
reductions with sw-IMRT differed considerably between patients and between
SWOARs, and depended on N stage and tumour location. The reduction of
the complication probability for the EORTC scores with regard to liquid foodswallowing and aspiration was smaller than 5% for all sw-IMRT plans. In
contrast, sw-IMRT reduced the complication probability with more than 5%for significant proportions of patients for the RTOG score and for the EORTC
solid and soft food swallowing scores. The reduction of the complication probabilities varies substantially among patients, as shown in Figure 1. A 5% reduction in complication probability, considered to be clinically significant, wasachieved for 57% of the patients with regard to the RTOG score, and for 73%
and 20% of the patients with regard to the EORTC solid and soft food scores,
respectively.

1355 poster
REDUCING IMRT DELIVERY TIME USING MORE BEAMS AND
FEWER SEGMENTS
K. Bratengeier1 , M. Gainey1 , M. Flentje1
1
J ULIUS -M AXIMILIANS U NIVERSITY,
Radioonkologie, Würzburg, Germany

Klinik für Strahlentherapie undPurpose: For IMRT, more gantry angles or more beams seem to be relatedwith delivery times. Based on theoretical considerations, it was proposed toreducing the delivery time using a single segment for each beam combinedwith an increased number of gantry angles. It was investigated, whether
classes of solutions of this type exist, whose plan quality can compete withconventional IMRT.
Materials: Step and shoot IMRT plans were created using direct aperture optimisation (DAO) as a reference. These plans were compared with an IMRT
variant having only one segment per angle ("2-Step Fast" IMRT). In this planning study, 2-Step Fast is based on a geometrical analysis of the topology ofthe planning target volume (PTV) and the organs at risk (OAR). Three clinicalcases and several plans utilizing the ESTRO-Quasimodo phantom were considered. The composite objective value (COV) was studied for comparison of
the plan quality.
Results: For 2-Step Fast, the number of segments was less than for thereference IMRT plan, the number of gantry angles was between 23 and 34.
The plan quality was comparable to, or better than, that of the reference plan.
The delivery time was measured for some examples. 2-Step Fast resulted ina delivery time reduction of 25 % for a modern linac with fast data handlingand 8 % for an older linac which forces test procedures for every single beam.

Conclusions: Swallowing-sparing IMRT significantly reduces the probabilityof dysphagia for a large proportion of head and neck cancer patients.

1357 poster
THE EFFECT OF AIR CAVITIES ON THE OPTIMIZATION OF HEAD
AND NECK MONACO IMRT TREATMENTS
V. Batista1 , R. Malveiro1 , G. Mora2
1
U NIVERSITY H OSPITAL S ANTA M ARIA, Department of Radiation Oncology,
Lisboa, Portugal
2
FACULDADE DE C IÊNCIAS U NIVERSIDADE DE L ISBOA, CFNUL, Lisboa,
Portugal
Purpose:Materials:
Results: Wrong block type.

S 507

increasing values for fIMRT plan independent on PTV volumes range (699
1700cm3 ), however for smaller PTVs these differences were smaller.
Conclusions: Overall, in more target volumes HT provided equivalent orslightly better bladder and rectum avoidance with a more uniform PTV, but
optimal results were achieved also with HT and fIMRT plans. However, fIMRT
showed improvements in OAR sparing while target volumes had smaller values, especially for low/intermediate risk group of patients. Addition benefit ofusing fIMRT treatment planning is that the process is less time consuming
and treatment team is smaller.

IMRT: Treatment verification and
QA
1359 poster
AN ANALYSIS OF ACCURACY OF DOSE USING THE COMPSSPROGRAM IN VOLUMETRIC MODULATED ARC THERAPY
H. D. Huh1
1
I NHA U NIVERSITY H OSPITAL, Departments of Radiation Oncology, andImaging Research, Inchon, Korea Republic ofConclusions: The exclusion of air cavity voxels of the PTV on the optimization of the head and neck treatment using Monaco TPS could lead to more
representative DVH of the PTV which contain about 20 % of air. 1) Paelinck
L, et al. Rad&Oncology 81 (2006) 250-256.2) Mora G, et al. Med. Phys. 35 ,(2008).
1358 poster
THE INFLUENCE OF TARGET VOLUME ON THE SELECTION OF
TREATMENT PLAN BETWEEN HELICAL TOMOTHERAPY AND
FIXED FIELD IMRT FOR PROSTATE CANCER
A. Skrobala1 , T. Piotrowski1 , A. Ryczkowski1 , T. Bajon2
1
G REATER P OLAND C ANCER C ENTRE, Department of Medical Physics,
Poznan, Poland
2
G REATER P OLAND C ANCER C ENTRE, Radiotherapy Department II,
Poznan, Poland
Purpose: This aim of this study was to compare and select an optimal IMRT
plan deriving from helical tomotherapy (HT) and fixed field IMRT plan (fIMRT)
delivery to patients with prostate cancer. By the dosimetric difference obtained from the dose-volume histograms (DVHs), a comparison was made toestimate whether different target volumes had influence on a chosen optimal
technique for patients. The aim was also to evaluate which technique provided better benefits of organs at risk (OARs) sparing for each PTV volume.
Materials: 50 patients were included in this study and divided into two groups:
25 with low/intermediate and 25 with high risk prostate cancer, all plans withsimilar dose-volume constraints for PTV and OARs. The mean PTV was
193±52cm3 for the first (1st ) group of patients and 1151±262cm3 for thesecond (2nd ). For each patient, two IMRT plans were created; for the firstgroup: HT and 5-field fIMRT to entire prostate or/and seminal vesicles, forthe second group: 7-field fIMRT to entire also pelvic nodal area. According to
growing values of particular analyzed PTV volumes, dose distribution for PTV,
bladder and rectum DVHs were compared for each patient. Both groups ofpatients were divided into two subgroups depending on the influence of PTV
volume on a chosen technique.
Results: Both techniques met the objectives with maximum dose, some deviations were observed with minimum dose for PTV for fIMRT. Both IMRT plans(HT vs. fIMRT) were thought to provide a similar mean dose for PTV: the 1stgroup (101.65 vs. 101.27%) and the 2nd group (101.46% vs. 101.02%).
Uniformity (D05 D95)/D95 were: 1st (3.32% vs. 5.48%) and 2nd (3.33%
vs. 4.63%). Femoral heads and intestinal cavity had doses at the tolerance
level with the lower values for the HT technique. Bladder doses for 1st groupwere divided into: a) PTV range (134183cm3 ) and bladder D70, D50, D30 for(HT vs. fIMRT) were (28.1% vs. 18.4%), (44.7% vs. 37.4%), and (66.1 vs.
66.2%), respectively; b) PTV volumes (185352cm3 ) were (32.1% vs. 35.3%),(49.7% vs. 56.8%), and (77.9% vs. 76.5%, respectively. In addition, rectum doses: for smaller PTV had similar values for DVH parameters for bothtechniques, while for bigger PTVs analyzed parameters increased for fIMRT
plan; for example D50 were 1st (39.1% vs. 43.3%), 2nd (36.9% vs. 52.5%),
respectively. For the 2nd group of patients, both the bladder and rectum had

Purpose: The aim of this study was to analyze the accuracy of dose of volumetric modulated arc therapy using the home made phantom, a glass detector and a compass program with matrixx detector.
Materials: In the Elclipse 8.6 environment, the arc optimizer was used to generate Volumetric Modulate Arc treatment plans that were for circle shape target, tow circle shape target and moon shape target. The treatment machineused in this study is a Clinac 23iX(Varian, USA). Each plan was measured
five times consecutively. Measurement was performed using the home mademulti-purpose VMAT phantom. Measurement Tools were a glass detector anda compass analysis program with matrixx detector. The mean gamma passing value were analyzed at the dose region for more than 95%(target) isodose
line and 50%-70% isodose line(critical region). Gamma analysis was used toverify correspondence between dose distributions. The gamma evaluation
criteria were 3% dose difference, and 3 mm distance to agreement. A point
dose at high isodose (e.g., 95% isodose) line and intermediate isodoses (e.g,50%-70% isodoses) was measured using the glass detector dosimetry.
Results: The analysis for single circle target resulted in 96.76%±2.18,
97.36%±3.13~97.36%±2.64 about 95% and 50-70% isodose line, respectively. For two circle shape target, the mean gamma passing value
was 98.06%±1.88 at the high dose region for more than 95% and98.06%±1.88 at the 50%-70% dose region. For moon shape target, themean gamma passing value was 99.51%±0.51 at the target region and79.71%±3.18~99.5%±1.0 at the crtical organ. The differences of Points
dose for the single shape target were 2%, 14%-15% at the target region andcritical organ region, respectively. The differences of point doses for two circle
shape targets were 4%, 5%~8% at the target region and critical organ region,
respectively. The differences of point doses for moon shape target were 5%,38.32%~49.74 at the target and organ region, respectively.
Conclusions: The measured dose using Matrix detector was consistentcalculated dose in the treatment planning system. But For glass detector
dosimetry, Difference showed very large at the severe dose gradient region.
We recommend that a point dose have to be measured particularly at the severe dose gradient region using the TLD, a glass detector and an ion chamber
for verification of VMAT plan.
1360 poster
ANATOMY-BASED QUALITY CONTROL OF IMRT PLANS EXECUTION
J. Winiecki1 , B. Drzewiecka1 , K. Ślosarek2
1
O NCOLOGY C ENTER, Medical Physics Department, Bydgoszcz, Poland
2
C ANCER C ENTER AND I NSTYTUTE OF O NCOLOGY, G LIWICE B RANCH ,,Medical Physics Department, Gliwice, Poland
Purpose: The conventional dosimetric QA procedures developed for IMRT
verification give only a partial picture of the quality of dynamic plans execution. Commercial solutions based on the Gamma Evaluation approach show
the level of the local dose deviation only, but they are not able to localise irregularities or specify what kind of tissue they refer to. Their solely quantitative
outcomes usually correspond more to the total area of the detector than theactually irradiated volume. It all makes the verification outputs hard to use
and imprecise.
Materials: To perform the complex monitoring of IMRT treatment the homemade software has been created and clinically examined. It is based ona Gamma Evaluation concept and allows accurate localisation of deviations
between predicted and acquired dose distributions, which can be registeredby EPID as well as film dosimetry. As a result of the comparison a histogram of gamma-value and a gamma-image (2-dimmentional representa-

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IMRT: T REATMENT VERIFICATION AND QA

IMRT: T REATMENT VERIFICATION AND QAtion of gamma-index spatial distribution) is created for each field. Finally the
gamma-images are with the corresponding DRRs combined.
Results: During last months we have examined nearly 300 dynamic plans.
There have been several patients treatet in our departament, when the presented solution allowed to continue the radiotherapy (the generated dose fluence was clinically acceptable), however the quantitative outcomes of the
gamma verification looked formalny bad.
Conclusions: It should be emphasized that IMRT-plan prepearing is a verytime comsuming procedure and patients start sometimes the treatment witha conventinal 3D conformal radiotherapy, if the examination of dynamic plans
was not succesfull. The presented solution demonstrates how the differencesin actual and expected dose distribution correspond to the target and organs
at risk. The method is rather dedicated to the head or H&N treatments, because the typically irradiated volumes are in these cases strongly determinedby the position of the bone structures, which are usually presented on DRR.

Results: The average pass rate for 15 IMRT partial brain irradiations was
98.5% (Γ: 3mm / 3%; SD: 1.0%) resulting in an AL (GT) of 96.5% (dose <10% Dmax excluded). Based on the Γ-distributions, the maximum (GM) andmean (GA) Γ AL of 2.5 (AVG(max Γ)=1.6, SD=0.5) resp. 0.4 (AVG=0.32,
SD=0.04) were derived.The table gives an overview of the QA-analyses forall 11 errors (pass: yes/no). All errors except case iii were rejected by the RO.

1361 poster
APPLICATION OF RECEIVER OPERATOR CHARACTERISTICANALYSIS TO IMRT QA
M. MacPherson1 2 , C. Cruje1 , M. Nielsen1 , M. Carlone2 1
1
C REDIT VALLEY H OSPITAL, Mississauga, Ontario, Canada
2
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO, Toronto,
CanadaPurpose: In medical imaging, receiver-operating characteristic (ROC) analysis is used to define the ability of a test to distinguish between normal andabnormal cases. Patient specific IMRT quality assurance typically compares
dose distributions measured and calculated in-phantom. However, the abilityof these tests to detect errors in delivery is not well understood. Here we
propose an application of ROC analysis to our IMRT QA system to assess its
sensitivity to known errors in MLC position and determine whether meaningful
thresholds for pass rate can be determined.
Materials: 94 DLMC IMRT treatment plans were randomly sorted into twogroups. One group was selected for MLC position modifications, and normally distributed positional errors (s=1 to 5 mm) were introduced to the open
MLC positions, while maintaining plan deliverability. The MLC modifications
were saved within new DICOM-RT Plans, and delivered to a 2D diode array(MapCheck2, Sun Nuclear). Plans from the unmodified group were also delivered to the diode array, and in each case the measured dose planes werecompared to the original calculated dose planes from the planning system,and evaluated using both g and DTA criteria (total number of fields =1692).
For DTA and g thresholds ranging from 1%/1mm to 3%/3mm, the false positive rate (FPR) and true positive rate (TPR) were taken as the fraction of
unmodified and modified plans respectively that failed to meet a preset passrate. For each level of MLC error and evaluation criteria, an ROC curve was
generated by plotting TPR against FPR. The areas under the curves (AUC)
were evaluated to estimate the most appropriate criteria and percent passcutoff for each level of MLC error.
Results: In general, gamma analysis exhibited consistently higher AUCs
than DTA, indicating superior diagnostic performance. As expected, more
stringent criteria increased sensitivity at the cost of specificity. Sensitivity
and specificity only exceeded 95% for position errors of >5mm, and gamma(3%/3mm).
Conclusions: We have applied ROC analysis to our IMRT patient specificquality assurance system. This has revealed that the system is unable todifferentiate between normally delivered plans and plans with MLC errors unless positional errors are very large. This approach may lead to the design ofimproved QA procedures.
1362 poster
ARCCHECK IMRT-QA: EXPLORING ITS SENSITIVITY TO INTRODUCED DOSIMETRIC ERRORS
P. Rietveld1 , M. de Goede1 , R. Wiggenraad1 , M. Eenink1 , J. van Egmond1
1
R ADIOTHERAPY C ENTRE W EST, The Hague, Netherlands
Purpose: The ArcCHECK (SUN Nuclear) is a relatively new QA device.
Its 1386 cylindrically oriented diodes (R=10.4cm, L=21cm) makes it a suitable design for QA of co-planar / rotational beam deliveries in clinical mode.
Which QA-parameters are applicable for detecting clinically relevant IMRTdosimetric errors with the ArcCHECK?
Materials: HW: Elekta Synergy (ELEKTA), ArcCHECK. SW: Pinnacle V8.0m(Philips), MapChECK V5.1.3 (SUN Nuclear).Clinical partial brain IMRT plans
are measured with the ArcCHECK and analysed. These results are used to
set default gamma (Γ) action levels (AL) to test the ArcCHECK’s sensitivity
on errors.Errors are introduced which lead to clinically undesirable treatments(as defined by a radiation oncologist (RO)): i) 4 plans (2 pts.) with 2-7%
increased OAR dose, ii) 2 plans simulating a ±5% dose error on the linac,iii) 2 measurements with one missing segment (> 5MU; 7 beams) and iv) 3
correct plans sent to a ±2, +3mm MLC-offset error on linac. This results in
6 incorrect plans (Pe) and 5 incorrect measurements (Me). Correct plans /measurements: P0 / M0.

In i, Pt. 1, the brainstem dose was just within limit. Both dose increases(≥2.4%) were rejected in analysis. In Pt. 2 (eye dose: 31.8Gy, criterion:
40Gy) both 4.3% and 6.5% increase in eye dose were rejected by GM only.
The systematic dose errors (case ii) of 5% are detected by GT and GA only.
A lost segment (iii), although clinically acceptable, is unacceptable from aphysics/ICT point of view and is detected by measurements. By using all
three Γ-parameters, all errors were detected.The effects of large fields andangular correction in measurements of H&N IMRT plans are under investigation.
Conclusions: The ArcCHECK is capable of detecting clinically non-approved
partial brain IMRT plans in the case of: suboptimal OAR sparing, MU calibration error, 1 missing segment, poor MLC calibration.The ALs of the Γparameters must be defined per tumour site (based on yet incomplete H&Ndata).
1363 poster
CHARACTERISATION OF THE MAPCHECK 2 FOR PRE-TREATMENTIMRT QA
H. Winter1 , T. Natarajan1 , R. Belton1
1
OXFORD C ANCER C ENTRE, Department of Medical Physics and ClinicalEngineering, Oxford, United Kingdom
Purpose: Detector arrays are often used for pre-treatment IMRT QA anda number of papers have been published demonstrating their overall performance[1]. Although the verification plan may meet the desired gamma
analysis criteria, there may still be detectors that fail within the region of interest. This could be due to a limitation of the array or a genuine discrepancy
between the planned and measured data.The purpose of this study is to investigate how the MapCHECK 2 diode array responds to a dynamic MLC
delivery and in particular, what the limitations are. The results are comparedwith the ImRT MatriXX ion chamber array.[1] Li. J. G., Yan G., and Liu C.,
Comparison of two commercial detector arrays for IMRT quality assurance.
Journal of Applied Clinical Med. Phys. 2009; 10(2):62-74.
Materials: The response of the MapCHECK 2 and MatriXX were evaluatedfor static fields for both 6MV and 15MV in terms of field-size, dose-rate,
source-to-detector distance (SDD), linearity, short and long-term reproducibility. In addition, the response of both detectors was investigated by delivery ofa sliding gap MLC field.
Results: Measurements made with both arrays were found to be reproducible
and linear. No field size or SDD dependence was observed. The MapCHECK
2 responded with dose-rate with the signal dropping by 0.7% and 1.3% from
600MU/min to 100MU/min for 6MV and 15MV respectively. No dose-rate response was found for the MatriXX. Both detectors showed a similar response
for dynamic fields, with increasing measurement uncertainty with decreasing
gap width and increasing leaf speed.
Conclusions: To avoid capturing the tongue-and grove effect the
MapCHECK 2 array should be offset by 2.0mm.

the pretreatment dosimetry for dynamic intensity modulated radiation therapy(IMRT).
Materials: The EPID has a continuous frame-averaging mode for portal
dosimetry. The pixel size is 0.4 mm. The frame acquisition value was 9.6
frames/sec. Calibration unit (CU) is a unique dose unit in the portal dosimetry,and 1 CU is equivalent to 100 monitor unit (MU). Dosimetric properties examined were as follows; 1) linearity of frame/MU and CU/MU, 2) changes of dose
distribution of IMRT test pattern, 3) ghosting effects of EPID, and 4) influenceof tongue and groove. A source-imager distance (SID) was 105 cm, and there
was no extra build-up material on the surface of the EPID. The ghosting effects were measured by a 200 cm2 static field delivered with15 seconds interval after delivery of 100 MU for a 100cm2 field. As clinical dosimetry, the dose
distributions of dynamic IMRT for prostate cancer (19 patients, 97 beams)
were measured by EPID, and they were compared with those of film andion chamber measurements. In addition, pretreatment dosimetry for prostate
IMRT (50 patients, 309 beams) was performed by EPID and evaluated using
the gamma method (criteria: 3mm / 3%).
Results: The frame and CU were proportional to the MU in the range of
10 to 1000 MU. The dose distribution of IMRT test pattern was stable in thedose-rate between 100 and 600 MU/min. CU values in the irradiated area
increased 0.2% compared with the area without pre-irradiation, indicating aghosting effect. The tongue and groove was also observed in EPID, and it
would be a cause for discrepancies. At maximum dose points in the clinical
IMRT beams, the results of portal dosimetry were 1.4 ± 1.0% higher thanthose of ion chamber measurements with the significant difference (p<0.05,
the pared t-test). The portal dosimetry for prostate IMRT beams were in good
agreement with the recalculated plan for portal dosimetry with an average ofmaximum gamma value of 1.37, and an average gamma value of 0.25.
Conclusions: Maximum dose points in the portal dosimetry were significantly but slightly higher than the ion chamber measurements. Therefor, thissmall difference seems clinically acceptable, the portal dosimetry system was
useful as a rapid and convenient verification tool for dynamic IMRT.
1365 poster
COMPARATIVE OF FOUR ARRAY DETECTORS FOR IMRT QA
L. Pereira1 , E. Meilan1 , F. Del Moral1 , A. Lopez Medina1 , A. Teijeiro1 , J.
Vazquez1 , B. Andrade1 , M. Salgado1
1
H OSPITAL DO M EIXOEIRO, Medical Physics, Vigo (Pontevedra), Spain
Purpose: Highly modulated beams in IMRT treatments demand an exhaustive quality assurance for verifying delivered dose. At present we can finda wide variety of devices for this objective. It makes difficult for a medical
physicist to select the best for the required purposes. In this paper we compare four array devices and we use the gamma index in order to evaluate thesensibility to detect several intentional errors.
Materials: IMRT plans for head and neck treatment were performed with
Xio®CMS (release 4.60.00). Plans were delivered by an Oncor Impression®linac (Siemens) equipped with a MLC of 41 leaf pairs.The selected
array devices are: MapCheckTM (array 2D; 445 diodes n-type, active area:
0.8 .8 mm2 ; Sun Nuclear), MapCheck2TM (array 2D; 1527 diodes n-type, active area: 0.8 .8 mm2 ; Sun Nuclear), ArcCheckTM (cylindrical geometry; 1386
diodes n-type, active area: 0.8 .8 mm2 ; Sun Nuclear) and MatrixxTM (array
2D, 1020 ionization chambers with an active volume of 0.08 cm3 , IBA dosimetry). We introduce several errors in calculated beams. The intentional errors
are: collimator rotation of 2 and 5, gantry rotation of 2 and 4, and isocentre
movement of 2 mm and 4 mm in the x-axis. All measurements were performed with single beams and gantry at 0. The variation in the gamma index(3 mm, 3% dose; Van Dyck’s criterium) between planned dose distribution
and measured dose were analyzed for each intentional error and for eachdetector device, considering a dose threshold of 10%.
Results:

1364 poster
CLINICAL EXPERIENCE OF AN AMORPHOUS SILICON EPID
DEVICE FOR PRETREATMENT DOSIMETRY OF DYNAMIC IMRTK. Matsumoto1 , M. Okumura1 , Y. Asai1 , K. Shimomura1 , M. Tamura2 , Y.
Nishimura2
1
K INKI U NIVERSITY H OSPITAL, Department of Radiotherapy, Osaka, Japan
2K INKI U NIVERSITY S CHOOL OF M EDICINE, Department of Radiation
Oncology, Osaka, Japan
Purpose: The aim of this study was to evaluate the portal dosimetry system
of Varian’s amorphous silicon electric portal imaging device (EPID, aS1000) in

The average difference in gamma index and its standard deviation for originalbeam and error-beam is shown in the figure for each system and for eachintentional error. In all beams Matrixx has the same capacity to detect theerrors despite their magnitude. MapCheck and MapCheck2 show different
response for each error. However, they have difficulties for detecting gantry
rotation. They are not designed to detect these errors, as they must be usedin the perpendicular plane to the beam axis. ArcCheck, is the best for detecting errors in gantry detection, as it’s designed to detect gantry rotation.

S 509

Conclusions: The capacity of these devices to detect errors is limited by
the size of the single detector, distance between the detectors, software corrections, and geometrical configuration. MapCheck and MapCheck2 are especially sensible to collimator rotations and displacements, and ArcCheckshows the maximum sensibility to gantry rotation, as it is specifically designed
for arctherapy quality assurance. Limitations of each device and hospitalneeds must be considered before choosing a specific device.This research
was supported by Consellere Econom Industria of Xunta de Galicia (Spain),under Grant 09SIN007CT.
1366 poster
DESIGN, FABRICATION AND IMPLEMENTATION OF PELVICANTHROPOMORPHIC PHANTOM FOR QUALITY ASSURANCE BY
USING GEL DOSIMETRY
H. A. Nedaie1 , S. A. Vaezzadeh2 , H. Sadoughi3 , M. Allahverdi4 , M. Aghili1 ,M. Esfahani1
1
I MAM K HOMEINI H OSPITAL , C ANCER I NSTITUTE, Tehran, Iran Islamic
Republic of2
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Tehran, Iran Islamic
Republic of3
M ASHHAD U NIVERSITY OF M EDIACAL S CIENCES, Mashad, Iran Islamic
Republic of4
T EHRAN U NIVERSITY OF M EDICAL S CIENCES R ADIATION O N, Tehran, Iran
Islamic Republic ofPurpose: With increasing interest to new radiotherapy techniques such as:
Intensity Modulated Radiotherapy (IMRT), IGRT, VMAT, and dose escalation,
it is necessary to provide advanced techniques to assure quality in treatment
delivery. An anthropomorphic phantom was used to address the accuracy of
3-D prostate dose.
Materials: An anthropomorphic pelvic phantom has been designed and fabricated for imaging, treatment planning, gel dosimetry applications and performing quality assurance. Its configuration was based on CT slices obtained
from a patient study. Individual slices were machined with corresponding
contours of the Prostate, Bladder, Rectum and Pelvic bone. The phantom
was made of Polymethyl-methacrylate (PMMA), while the pelvic bone and femurs were made of bone equivalent material, polytetrafluoroethylene (PTFE).
Cylindrical grooves were machined in the phantom to allow placement ofionization chambers for dosimetry of prostate, bladder, rectum and femoral
heads. In addition, prostate, bladder and rectum were filled with MAGIC- typenormoxic polymer gel, and then phantom was irradiated by Cobalt-60 gamma
ray, 6 MV and 18 MV X ray.

Results: The phantom is being used to verify the consistency of a rangeof processes in radiation therapy simulation, planning and delivery of 3Dbased treatments for prostate cancer. Relative difference between calculated
and measured doses from In vivo dosimetry were 1.4%, 0.0%, 3.0% and5.0% for Prostate, Bladder, Rectum and Femoral head, respectively. For gel
dosimetry, the resolution of MR images for gel dosimetry was 1.4 mm3. Mean
Distance to agreement (DTA) and mean Dose Difference were 2.98 millimeterand 6.2% in comparing of profiles obtained from ionization chamber and gel
dosimetry profiles, respectively. Mean relative difference of DVHs between
gel dosimetry and TPS data were 3.04%, 10.4% and 11.7%, for prostate,
bladder and rectum, respectively.
Conclusions: In-vivo dosimetry and gel dosimetry showed that the treatment
accuracy for target volume and organs is acceptable. The ultimate study objective was to use the phantom to assess the accuracy of treatment planningsystems, for dosimetric research problems and QA in treatment of prostatecancer.

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IMRT: T REATMENT VERIFICATION AND QA

IMRT: T REATMENT VERIFICATION AND QA

1367 poster
DEVELOPMENT OF A FREEWARE FOR THE AUTOMATIC REGISTRATION DURING IMRT QUALITY CONTROL WITH FILMS
F. Del Moral1 , E. Meilan1 , L. Pereira1 , F. Salvador1 , V. Muñoz2 , M. Salgado1
1
H OSPITAL DO M EIXOEIRO, Medical Physics Department, Vigo (Pontevedra), Spain
2
H OSPITAL DO M EIXOEIRO, Radiation Oncology, Vigo (Pontevedra), Spain
Purpose: Quality control with films in techniques like IMRT demands theregistration of the film image with the results from the treatment planning system. Performing this process manually can be very complex or even impossible for anthropomorphic phantoms, where it is not easy the use of reference
markings in the film, or when dose planes in arbitrary directions are required
and the treatment planning system does not allow its generation.As a consequence, this process can relied totally on the skills of the operator, causing
very different evaluations of indices like γ 3%,3mmIn this work, like part of thecommissioning of the e-IMRT system (a Monte Carlo in net for the calculusof IMRT treatment plannings), it has been developed a software for the automatic registration of the image of the film with the results of the treatment
planning system.
Materials: It has been used the free libraries of the Insight Segmentation
and Registration Toolkit (ITK, version 3.17), the Grassroots DICOM Library(GDCM, version 2.0.14) and the Numerical Recipes in C++ (NR, version2.10). For this purpose the program has been structured in an executablewith the visual interface and two .dll libraries. The interface is written in VisualC++ in its Common Language Infrastructure (CLI) specification implemented
in Microsoft Visual C++ Express 2008. One of the .dll libraries is written in
C++, and makes used of the ITK, GDCM and NR libraries. Finally the other.dll library behaves as the link between the interface and the previous library.
Results: The program uses as data the image of the film in TIFF format
and the DICOM RTDose generated by the treatment planning system. It
returns three dose planes: a non-registered plane at the position selectedby user, this dose plane registered in 2D with the film, and finally the plane
result from the registration in 3D of the dose matrix with the film. Final resolution of the dose planes is the same as the film. For this purpose it ispossible to choose interpolations of the following types: nearest neighbor, linear, bicubic spline and windowed sinc (Hamming, Cosine, Welch, Lanczos orBlackman) with radius from 1 to 5 pixels.In order to perform registrations it
has to be selected a type of metric (mean squares, normalized correlation,mean reciprocal square difference, mutual information, Mattes mutual information, Kullback-Leibler compare histogram, normalized mutual information
histogram, mean squares histogram or correlation coefficient histogram), a
type of interpolation among the previous, and an optimizer (gradient descent,regular step gradient descent and one plus one evolutionary).Depending on
the type of selected metric it will also be necessary to perform the conversionof pixel value to dose in the image of the film. For this purpose the program
uses the dose vs. pixel value calibration file in Omnipro I’mRT format or in.txt format, and the user has to specify a fit to a polynomial or to bicubic
splines.Position and type of the first dose plane to extract (coronal, sagittalor transversal) is given by the user by means of its absolute position or bymeans of the position of the isocenter of the treatment planning (filling up its
coordinates of providing the DICOM RTPlan file) and a relative offset.

Conclusions: The developed software removes the operator-depending factor in the registration of the film image with the results of the treatment plan-ning system and it allows the use of different registration models. The application can be provided by any of the authors on request.
1368 poster
DOSIMETRIC EVALUATION OF NON-RIGID IMAGE REGISTRATION
OF CT TO CONE-BEAM CT IMAGES WITHIN THE PROCESS OF
ADAPTIVE RADIATION THERAPY FOR HEAD AND NECK PATIENTS.
V. Rompokos1 , D. D’Souza2 , I. Rosenberg2 , P. Davies2 , S. A. Moinuddin2 ,R. Mendes2
1
U NIVERSITY C OLLEGE H OSPITALS NHS T RUST, Radiotherapy physics
group, London, United Kingdom
2
U NIVERSITY C OLLEGE H OSPITALS NHS T RUST, London, United Kingdom
Purpose: The aim of this study was to improve the process of selecting patients who would benefit from a re-optimized IMRT plan by using CBCT images acquired in the treatment position (primary set), CT images from treatment planning (secondary set) and a non-rigid registration algorithm.
Materials: In order to verify the accurate positioning of the patient and of theinternal anatomy between treatment planning and treatment delivery, Headand Neck patients undergoing Intensity Modulated Radiation Therapy (IMRT)
treatments are scanned on a weekly basis with an on board cone-beam CT.
For this group of patients, weight loss and soft tissue changes in the area of
the neck is a common occurence. The main challenge for the clinician is toevaluate whether the impact of these changes on the doses to risk organs(e.g. spinal cord) and the PTV is critical. These anatomical changes are currently managed locally by putting the patients through the treatment planning
process again when the geometric distance from the vertebrae to the surfaceof the neck is reduced by more than a certain limit. However this approachis not based on any dosimetric evaluation, is time consuming and puts thepatient under further stress.
Results: The images were processed by a commercially available software(Velocity Medical Solutions) that uses a modified B-spline registration algorithm. The deformed CT images were evaluated dosimetrically using the analytical anisotropic algorithm within the IMRT treatment planning system.
Conclusions: By producing an integrated dose volume histogram (DVH)
based on the deformed images on a weekly basis, the anatomical changes
can be assessed in terms of dosimetry risk to give our multidisciplinary team abetter understanding on the need for a repeat planning CT and a re-optimized
treatment plan.
1369 poster
DOSIMETRIC INVESTIGATION OF PATIENT SPECIFIC QA USING
FOUR DIFFERENT COMMERCIAL 2D DETECTORS.
M. Yamada1 , M. Oita2 , K. Kai1 , K. Ogawa1 , K. Matsuda1 , K. Iwasaki1 , S.
Kuroda3 , S. Takahashi4
1
S HIMANE P REFECTURAL C ENTRAL H OSPITAL, Radiological Technology,
Izumo, Japan
2
O KAYAMA U NIVERSITY G RADUATE S CHOOL OF H EALTH S CIENCES,
Okayama, Japan
3
S HIMANE P REFECTURAL C ENTRAL H OSPITAL, Radiology, Izumo, Japan
4
S HIMANE U NIVERSITY FACULTY OF M EDICINE, Radiological Technology,
Izumo Shimane, Japan
Purpose: Patient specific QA is important process for routine practice in Intensity Modulated Radiotherapy (IMRT). The purpose of this study was toevaluate and compare the four different commercial 2D detectors for prostate
IMRT in our hospital.
Materials: We have used Trilogy system (Varian) with 10 MV photon beams.
From November 2008 to June 2010, 13 plans and total of 85 fields which
underwent prostate IMRT were used. For all QA plans, the corresponding verification dose distributions were obtained using four different commercial 2D detectors. This include two films (Kodak EDR2, GafChromic EBT2),
MapCheck(SunNuclear) and EPID(Varian aS1000). All QA plans and deliveries were calculated and delivered coronal plane. All measurements werecompared against calculated ones by taking into account all points in themeasurement plane and second by applying threshold value where the points
that received less than appropriate percentage dose were excluded from the
gamma index calculation.
Results: For overall QA plans, using all available points for the
gamma calculation, 93.7±2.5% and 90.1±5.7% of them passed the criteria(3%/3mmDTA/Th30%) of having gamma values less than 1 using EDR2
films and EBT2 films. 99.4±1.1% and 97.9±2.7% of them passed the criteria(3%/3mmDTA/Th10%) as well using a MapCheck and EPID. However, theresults showed that there are significant differences between four detectors
which were depended on the setting of threshold percentage doses of eachdetectors.
Conclusions: In this study, all patient QAs passed the routine clinically criteria of gamma index values of 3%/3mm DTA. We have also found that thecorrelation of pass rate using gamma index between EDR2 and EBT2, EDR2
and MapCheck. It was suggested that dosimetric systems under investigation
can be used interchangeably for routine patient specific QA.

1370 poster
DOSIMETRIC VERIFICATION OF IMRT TREATMENTS USING A 2D
ION CHAMBER ARRAY
M. Marcantonini1 , C. Raymondi1 , C. Zucchetti1 , M. P. Leogrande1 , C.
Aristei2 , G. Gobbi1
1
O SPEDALE S ANTA M ARIA DELLA M ISERICORDIA, Medical Physics, Perugia,
Italy
2
O SPEDALE S ANTA M ARIA DELLA M ISERICORDIA, Radiotherapy, Perugia,
Italy
Purpose: The IMRT technique is an advanced form of conformal radiotherapy, which adds to the target conformation the fluence modulation. The modulation is achieved by MLC movement and is optimized by the use of specificsoftware for treatment planning called Inverse Planning. The inverse planning
starts from a distribution of the optimum and clinically effective dose and tries
to determine the treatment parameters that are able to produce it in the patient. In the Radiation Oncology Department of our Hospital step-and-shoottechnique is applied. In the IMRT technique, verification of patient-specificdose distribution is necessary to ensure the proper implementation of treatment. In the Medical Physics Department of our Hospital an internal protocolof dosimetric verification was defined. The purpose of this paper is to illustrate
the dosimetry system applied and to show results for prostate and head&neck
cancer IMRT treatment plan verification.
Materials: Planar dose distributions were measured using MatriXX (IBA
Dosimetry). MatriXX consists of a two-dimensional 1020 ion chamber array(active area 24.4 x 24.4 cm2 ). Each ion chamber has a diameter of 4.5 mm
and a height of 5 mm for a sensitive volume of 0.08 cm3 , detector spacingis 7.6 mm. For each patient treatment, the dose distribution of each photon
beam was measured. Distributions were compared with those calculated by a
TPS Pinnacle3 (Philips) with a 2 mm grid. The software OmniProI’mRT(IBA)
was used for dose comparison. The dose distributions were normalized tothe maximum and the agreement was evaluated using the Gamma function(3% dose tolerance and 3 mm distance-to-agreement). Measured dose distribution was interpolated with 2 mm grid. Acceptance criteria for fraction of
pixels with gamma index below 1: prostate cancer (5 portals) minimum 85%- optimal 90% and head&neck cancer (7/8 portals) minimum 90% - optimal
95%.
Results: 50 and 20 treatment plans for patients with prostate cancer andhead&neck cancer respectively were analysed. For each portal of planned
treatments, dosimetric verification was made determining the percentage of
pixels with gamma index below 1. The mean (± standard deviation) percentages of pixels with gamma indices passing the criteria were 92%±3% and97%±2% for patients with prostate and head&neck cancer respectively.
Conclusions: Results verify the stated acceptance criteria. Points that failed
the test, due to large detector size and spacing, were located in high dose
gradient regions. This protocol of dosimetric verification is fast and reliable
and can be used to verify patient-field specific dose distributions in IMRT
techniques. Film dosimetry will be developed to improve dose agreement ina selected number of patients.
1371 poster
EVALUATION OF GAMMA INDEX CALCULATION TOOLS FOR IMRTQUALITY CONTROL
A. R. Figueira1 , V. Batel1 , A. L. Carvalho1 , T. S. Reis12 , G. Pinto1
1
H OSPITAL S ÃO J OÃO, Serviço de Radioterapia, Porto, Portugal
2
E SCOLA S UPERIOR DE T ECNOLOGIA DA S AÚDE DO P ORTO, Porto, Portugal
Purpose: Quality Control of IMRT treatments usually involves the comparison of calculated dose maps from the treatment planning systems (TPS) withmeasured dose maps using films, 2D arrays or portal dose images. Usually
this comparison is done by using the gamma index analysis. In our department we have available two commercial systems for doing this.The purposeof this work was to evaluate the way these two different commercial systems
analyse a set of test fields as to understand their potencial and limitations
when using them in real clinical situations.
Materials: We used calculated dose plane distributions from CMS XiO treatment planning system to test the IMRT analysis tools: RIT113 v5.0 (Radiological Imaging Technology, Inc.) and OmniPro I’mRT v1.6.0009 (Scanditronix
Wellhofer). Instead of using real films or 2D array images, to avoid the uncertainty of the dose delivery in the linac, we created a set of fields, withdifferent levels of intensity patterns, to use as input data to the IMRT analysis systems. For each field several dose maps were created by deliberately
introducing differences, like shifts in perpendicular directions, dose level or
MLC leaf position. Each of these modified dose maps was compared withthe original one. Differences in the results found for the two systems werethen analysed in terms of number of pixels used, maximum, minimum andaverage gamma index values, number of points passing the gamma index
criteria and avaliable display tools.
Results: Differences were found between the analised systems in termsof image registration procedure, dose normalization, adjustable parameters,
limiar of detection of differences in dose and/or position, gamma value statistical distribution. Situations were found were the same dose map would pass

S 511

the tolerance criteria in one of the systems and not on the other.
Conclusions: Since the pass/fail decision in real clinical IMRT situations isoften based on this gamma index analysis, the calculation algorithms andparameters used on these systems should be well understood and configured
before used. Incorrect configuration can lead to erroneous results when using
real films or 2D array images.This work allowed us to establish an internal
protocol and to define tolerance criteria for both systems.
1372 poster
EXPERIENCE OF PATIENT-SPECIFIC QA FOR VMAT WITH DIFFERENT INSTRUMENTS.
F. Declich1 , F. Bonsignore1 , I. Butti1 , C. Frigerio1 , G. Sangalli1
1
A.O. DELLA P ROVINCIA DI L ECCO, Servizio di Fisica Sanitaria, Lecco, Italy
Purpose: Since January 2010 we have been using a new commercial TPS
able to create inverse VMAT planning for Elekta accelerators. In this work
we describe our experience in the quality assurance measurements of VMAT
plans with different kind of instruments, especially with ArcCHCECK (Sun
Nuclear Corp.).
Materials: The TPS used for this study is Oncentra Masterplan (NucletronB.V.), with the new inverse planning module for VMAT. For complex treatments, as head & neck and pelvis, we use the "dual arc" technique: it consists in two arcs of the same length, alternating between clockwise (CW) andcounter-clockwise (CCW) rotation. Our typical solution consists in a dual arc
plan, composed by two arcs 356◦ length and 4◦ spacing, namely 89 control
points for both arcs. We use a single arc only for structures with a simple geometry. Our instrument for routine patient-specific QA is ArcCHECK. For a setof representative plans we used other two dosimetric systems: MapCHECK2(Sun Nuclear Corp.) integrated with a square solid water phantom (MapPHAN) and Octavius (PTW).
Results: We performed 43 patient-specific QA measurements with ArcCHECK: 26 for head & neck, 16 for pelvis region and 1 for lungs. 33 ofthese were double arc and 10 single arc plans. The average gamma analysis
passing rate was 97% at 3%/3mm. If we separate in two groups according to
the technique (single arc, double arc), we observe an average passing rateof 96.7% for single arc, 97.6% for the first arc and 96.5% for the second arc
in double arc technique. For 7 head & neck plans and 7 pelvis plans, QA
measurements were also performed with Mapcheck2 and Octavius. The results were very similar for ArcCHECK and Octavius, respectively 98,2% and97,5% average passing rates. Instead for MapCHECK we observed a 92,5%
average passing rate (p<0.05).
Conclusions: The results obtained with ArcCHECK show a good agreement
between calculated and measured doses. We didn’t observe significant differences in passing rates between single arc and dual arc plans, despite double
arc technique provides more complex and critical solutions (small MLC apertures, fast gantry and MLC leaves movements and low dose rate). Regarding
comparisons between different instruments, the three systems provide acceptable QA results for all cases. Doses measured with ArcCHECK and Octavius agreed better with plans in respect to MapCHECK2, probably due to aworse angular dependence of diodes in the plane arrangement, particularly
at gantry angle near 90◦ and 270 ◦ , and a not ideal shape of the MapPHAN
phantom for rotational treatments.
1373 poster
IMPACT OF MICROCT ACQUISITION AND RECONSTRUCTIONPARAMETERS ON TUMOR DELINEATION IN ORTHOTOPICGLIOBLASTOMA MULTIFORME
J. Chunta1 , J. Torma1 , R. Kuo1 , G. Wilson1 , A. Martinez1 , B. Marples1
1

W ILLIAM B EAUMONT H OSPITAL, Radiation Oncology, Royal Oak, USA

Purpose: To evaluate the impact of microCT acquisition and reconstruction
parameters on tumor volume delineation for treatment planning of Glioblastoma Multiforme (GBM).
Materials: Orthotopic U87-MG GBM xenografts (n=50) were established infemale nu/nu mice and treated daily with 2 Gy X-irradiation for 7 consecutive
days to a total of 14 Gy using two treatment regimes (single 200 cGy fraction or 10 pulses of 20 cGy in 45 mins). Tumor response was determinedusing contrast-enhanced microCT (Omnipaque) using a GE FLEX TriumphTM
combined PET-SPECT-CT system with CT energy set to 50kVp/800µA or
80kVp/250µA. Raw microCT data were analyzed with varying reconstruction
parameters and algorithms (e.g. down-sampling, beam hardening corrections, etc.) with Exxim COBRA and visualized and compared using MicroView(GE) and VIVID (Gamma-Medica Ideas). Resulting images were qualitatively
analyzed for the existence and intensity of artifacts and for ease of tumor
volume delineation.
Results: Fewer streak artifacts and better tumor margin contrast enhancement was evident using high voltage with low relative current (80kVp/250µA)
acquisition parameters for both radiotherapy treatment regimes. In addition,these imaging parameters were associated with an almost 10-fold reduction
in radiation exposure. Better tumor margin delineation was seen with reconstruction parameters that functioned to down-sample, or average the raw

S 512

IMRT: T REATMENT VERIFICATION AND QA

IMRT: T REATMENT VERIFICATION AND QA

data across detector pixels. Whereas beam hardening corrections and streak
artifact-reducing algorithms decreased image quality. Overall tumor volume
sensitivity was 2-3mm3 with the high voltage-low current acquisition as compared to 5-15mm3 with the low voltage-high current, depending on tumor location with respect to artifacts.
Conclusions: This pre-clinical study demonstrated that down-sampling highvoltage-low current microCT data, with a reduction in reconstructed image
pixel sizes, produced higher quality images and more accurate tumor volume
delineation than low voltage-high current imaging. Such a protocol decreases
both radiation exposure and streak artifacts. This type of acquisition could beapplied with evolving technologies that permit proper radiation treatment planning using a collimated beam for small animal work, which can be accurately
and reproducibly applied.
1374 poster
IMRT DOSIMETRIC VERIFICATION PROCEDURE
S. Pellejero1 , S. Lozares1 , A. Forner1 , U. Iriondo1 , A. Otal1 , P. M. Soto1 , F.
Maneru1 , M. L. Martin-Albina1 , S. Miquelez1 , A. Rubio1
1
H OSPITAL DE N AVARRA, Servicio de Radiofísica y Protección Radiológica,
Pamplona, Spain
Purpose: In 2009 our centre has introduced clinically treatments with intensity modulated radiation therapy (IMRT), in complex RT techniques, suchas IMRT, it is recommended pre-treatment patient-specific quality assurance(QA). Ibbot (2009) reported that agreement between calculation and measurement is often not reached for many centres using IMRT, and strongly
recommends that patient specific QA be performed for all patients having
IMRT. It is recommended that patient-specific QA not rely on a single method
exclusively for all patients.We have developed a patient specific QA programfor IMRT patient pre-treatment verification.
Materials: Results of the verification of IMRT treatment of 100 patients ofthe Hospital de Navarra, from September 2009 until November 2010 are
showed. Measurements were made on a Varian Trilogy LINAC (Varian Inc.
Palo Alto USA). In the testing of each patient was measured: 1) Measurements of absorbed dose in phantom (IBA and PTW IMRT verification phantom) and ionization chamber PTW 125 cm3 and pinpoint chamber. Measuringdoses (high and low) in low gradient areas. The percentages are referred tothe prescribed dose. Analyzed with gamma analysis (Low et al 1998).2) 2D
dose distributions for each individual beam, at 5 cm depth of PTW RW3 by
PTW seven29 2D array comparing the distribution of Eclipse through Verisoft(PTW) software. 3) Portal dosimetry (Eclipse) . Analyzed with gamma analysis (Low et al 1998).
Results: Measurements of absorbed dose in phantom are inside acceptability criterion (2%). 2D measurements with ionization array chamber also (3%3mm gamma analysis) and so Portal Dosimetry
Conclusions: Quantitative parameters calculated for a given criterion of acceptability should be adopted in conjunction with displays that show wherediscrepancies occur. Planning and delivery systems which cannot meet therequired standards of accuracy, reproducibility and stability to reduce verification will not be accepted by the radiotherapy community
1375 poster
PREDICTION OF PORTAL DOSE IMAGES FOR IMRT VERIFICATIONWITHOUT CORRECTION FACTORS
G. Budgell1 , J. Berresford1
1

T HE C HRISTIE NHS F OUNDATION T RUST, North Western Medical Physics,
Manchester, United Kingdom
Purpose: Portal dosimetry is a routine tool for IMRT verification. However,
the TPS models used to predict portal dose images (PDIs) for comparison
with EPID measurements typically incorporate a series of corrections for thenon water-equivalence of the EPID and for the effect of the flood-field calibration. The purpose of this work was to generate a beam model for PDI prediction within a commercial TPS based only on direct measurements madeusing the EPID, thus considerably simplifying the PDI prediction process.
Materials: 6MV square fields from 3x3 cm2 up to 25x25 cm2 were imaged at
105 cm FSD using an amorphous silicon EPID mounted on a Varian 600C/D
Clinac. Output factors were measured from the greyscale in the central regionof each field. Beam profiles and output factors were then imported into Pinnacle TPS v8.0 and used to create an ’EPID’ model. In Pinnacle beam parameters are iteratively adjusted until a good match is achieved to the measured
profiles a match with the EPID profiles was achieved at a nominal 5cm depth.
A series of complex H&N IMRT plans were transferred to the new model and
PDIs calculated. The fields were delivered to the dose-calibrated EPID and
the EPID fluence maps compared with the PDIs using absolute doses andgamma evaluations.
Results: For the 35 fields measured, the mean absolute agreement between
measured and predicted dose in a low dose gradient, high dose point was+0.1% with a range of -1.6% to +2.1%. The mean percentage of pixels passing a 3%/3mm gamma evaluation within the 20% isodose was 98.8%, with arange of 97.4% - 99.8%.

Conclusions: Good agreement was found between the EPID measured fluence maps and the predicted PDIs. It is possible to accurately predict PDIs
for IMRT verification using a purely measurement based model within a commercial TPS.
1376 poster
RELATING DOSIMETRIC OUTCOME TO COMPLIANCE
PATIENT SPECIFIC QUALITY CONTROL CRITERIA IN IMRT
A. Rangel1 , P. Dunscombe1
1

WITH

fraction level. However, for many sites, anatomical changes still are the major
cause of problems and the detected deviations are correct.
Conclusions: The presented statistics reassure the validity of the method
applied and show that most of the analyzed IMRT fields met the clinical criteria. However the different percentages within criteria will help us prioritisedevelopment work for each site. Finally, the statistics software will enable
us to evaluate results per fraction, compare results on different linacs, checkclinical protocols and keep providing valuable feedback for our method. Table
1:

TOM B AKER C ANCER C ENTRE, Medical Physics, Calgary, Alberta, Canada

Purpose: by introducing controlled perturbations into planar dose maps usedfor verification of IMRT plans to explore the relationship between compliancewith patient specific quality control criteria and the change in 3D dose distribution as summarized by the Equivalent Uniform Dose (EUD).
Materials: three IMRT head and neck (H&N) and three IMRT prostate plans
were used as reference plans in this study. Perturbations of two types wereintroduced into the planar dose maps associated with each of the six plans.
To simulate dose differences that appear randomly across planar dose maps
each point in the fluence map was perturbed by adding a value selected froma normal distribution. The second type of perturbation was a combination of
random dose differences plus a 1% systematic dose difference intended tosimulate an offset such as might be caused by output variation of the accelerator or by an incorrect dosimetric leaf gap. The perturbed dose maps, derived
from the perturbed fluence maps, were evaluated against the reference maps
using the widely accepted criterion of 90% of the measurement points passing either 3% absolute dose difference or 3 mm distance and a minimum dose
difference of 2cGy. The perturbed fluence maps were also used to generate
dose distributions which were compared with the reference dose distribution
in terms of changes to the EUDs of the CTV, PTV and selected organs at risk
(OARs).
Results: The widely accepted criterion of acceptability as used in this study
for the verification of planar dose distributions has been shown to prevent
point by point differences from causing changes greater than 2% in the prescribed EUDs of the targets and 2 Gy for OARs. However if systematic offset
differences are present, due to for example an incorrect dosimetric leaf gap,
the patient specific validation criterion may be satisfied but a 2% / 2Gy requirement on clinical dosimetry may not be met.
Conclusions: to ensure acceptable accuracy in IMRT delivery both the output of the machine must be tightly controlled, as for any conventional treatment, and the dosimetric leaf gap must be accurately modeled. The resultsof this study raise questions on the efficiency of IMRT patient specific checks
in detecting important errors for the treatment outcome.
1377 poster
RESULTS AFTER YEARS OF DAILY CLINICAL PRACTICE WITH IN
VIVO IMRT EPID DOSIMETRY
I. Olaciregui1 , Y. Szeto1 , A. Mans1 , R. Tielenburg1 , R. Vijlbrief1 , R. Van der
Sluis1 , R. Rozendaal1 , B. Mijnheer1 , J. J. Sonke1 , M. van Herk1 , J. Stroom1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Amsterdam, Netherlands

1

Purpose: Our back-projection EPID dosimetry method is clinically applied for
2D IMRT verification of all curative treatments. The routine clinical procedure
is to perform in vivo verification for the first three fractions of all our treatments while pre-treatment verification occurs only exceptionally. This study
uses for the first time statistics of all our in vivo 2D IMRT results to give us aretrospective view of the accuracy of the method.
Materials: Our EPID dosimetry method reconstructs the dose within the patient volume in multiple planes parallel to the EPID. For IMRT in vivo verification, a 2D γ -evaluation (3%/3mm) between the EPID-reconstructed andplanned dose distributions in the isocenter plane is performed within the 20%isodose of the planned maximum dose. A measurement is approved when
the clinical criteria are met for the first three fractions combined: dose difference percentage at the isocenter (%∆ ISOC) < 5%, γ -mean <1.0 andpercentage of points with γ <1 (%γ <1) > 70% (%∆ ISOC<7%, γ -mean<2.0
and %γ <1>50% for breast). For this study we have built analysis softwareand a database with all our in vivo IMRT results produced over the years.
Outliers due to user or input data errors, software bugs or restrictions wereleft out (around 5% of the total). A field is considered an outlier if it lies outside
the Mean ± 2SD range for any of the aforementioned criteria.
Results: In total around 4,500 patients and 90,000 IMRT portal images wereanalyzed. Table 1 presents the total number of analyzed images, the percentage of fields that meet the clinical criteria and the average values of %∆ISOC, γ -mean and %γ <1. The average %∆ ISOC value is close to zero formost sites indicating that the EPIDs are well calibrated. The average γ -mean
and %γ <1 values are well within the clinical criteria for all sites. The large
differences in the percentage of fields within criteria can be explained by the
known limitations of our model, e.g. tissue inhomogeneities and wedges, indicating that additional work needs to be done. Also fields with very low doses(e.g. breast) usually show large %∆ ISOC deviations that are not relevant at

1378 poster
SET-UP ERRORS IN PROSTATE CANCER PATIENTS TREATED
WITH IMRT: RESULTS OF A MONOISTITUTIONAL EXPERIENCE.
M. Lupattelli1 , S. Saccia1 , E. Romagnoli1 , A. Milletti1 , S. Pallottini1 , S.
Russo1 , F. Paglione1 , F. Tamburi1 , S. Trinari1 , S. Cusco1 , R. Bellavita1 , C.
Aristei1
1
R ADIATION O NCOLOGY P ERUGIA, Perugia, Italy

S 513

1379 poster
STUDY OF THE NEW SOFTWARE “3DVH™” FOR HEAD AND NECK
CASES
C. Dejean1 , J. Feuillade1 , M. Gautier1 , S. Marcié2
1

C ENTRE A NTOINE L ACASSAGNE, Department of Physics, Nice, France
C ANCER C ENTER A NTOINE -L ACASSAGNE . U NIVERSITY N ICE S OPHIA A NTIPOLIS, Department of Physics, Nice, France

2

Purpose: A new software "3DVH™" is provided to calculate the discrepancies between calculations and measurements in each anatomic region of interest for IMRT. In this study, the software has been used for head and neckcases.
Materials: Head and neck patients are treated by IMRT on Varian linacs. The
quality control is performed with Mapcheck1, beam by beam, gantry at 0◦ .
The dose distribution is calculated with Eclipse TPS. Parameters were send tolinacs via MOSAIQ record and verify system.For the new software, DicomRT
plan, image, structure and dose are transferred from the TPS. Comparison
between calculations and measurements of each beam are performed The
gamma index is used (3%, 3 mm). The software created a file with discrepancies of each comparison. With all of these information, "3DVH" calculates
DVH which are compared to DVH calculated by the TPS. Discrepancies on
the mean and maximal dose, the number of voxels which dose are without
the limits, of each anatomic region of interest, are given.
Results: For 20 patients treated for head and neck disease, mean and maximal measured dose are inferior to calculated dose. For each anatomic regionof interest the % of voxels within the limits, the total number of voxels, thenumber of voxels above the limits and the number under the limits are given.
It appears that the total matching rate (for all voxels) is inferior (discrepancy< 5 %) to the mean value of the number of points within the limits for beams
excepted in 2 cases (8 %). It is difficult to explain this difference but it meansthat a 3D comparison is useful.
Conclusions: This new software gives more data than measurements ofeach beam. This first study shows the interest of a 3D comparison. The analyse is more difficult and must be done for each anatomic region of interest.
Other studies must be performed.
1380 poster

Purpose: Portal images have been used to verify patient set-up based onalignment of the bony pelvis. We retrospectively analyzed the set-up reproducibility of patients affected by prostate cancer treated with IMRT.
Materials: all patients were treated in supine position using a knee-ankle fixation device (COMBIFIX) in order to facilitate the set-up reproducibility. Spiralcomputed tomography (CT)-scan was acquired obtaining 5 mm slice thickness images spaced from L4 to 2 cm below the ischeal tuberosities. The PTV
was obtained by a 10 mm expansion around the CTV except for the posterior
margin where a 5 mm expansion was used towards the rectal wall. During
the first treatment session, the patient was aligned by the laser system withthe three skin tattoos and two orthogonal EPID images (anterior-posterior
and latero-lateral) were acquired. The images were matched with the digitally reconstructed radiographs (DRRs). The alignment was validated by aradiation oncologist on the basis of bone anatomy. EPID images were thenobtained twice weekly and examined during the course of treatment by thetreating radiation oncologist. Whenever the radiation oncologist ordered portal film shifts (> 2mm), all future EPIDs were taken using the ordered shifts
from the original set-up marks. For the purpose of the study, all the EPID
images were reviewed by a single observer (ML). Means and standard deviations were used to describe the distributions of EPIDs shifts in the three
separate dimensions (X, Y, Z).
Results: In the present study we analyzed the setup reproducibility of 19 patients affected by prostate cancer treated with IMRT at our Department from
June 2009 to September 2010. All patients received a total dose of 74.25Gy
in 33 daily fractions of 2,25Gy; in three cases seminal vesicles were included
in treatment volume and received 62Gy in 33 daily fractions of 1,88Gy. A totalof 831 EPIDs were reviewed; an average of 44 EPIDs for each patient. The
mean shift of systematic errors in the right-left (RL), supero-inferior (SI) andantero-posterior (AP) directions was 2.6, 2.73 and 3.8 mm, respectively. The
mean shift of random errors in the RL, SI and AP directions was 1.38, 2.2
and 1.9 mm, respectively. The mean values of standard deviations related toboth inter- and intra-fractions shifts in the RL, SI, AP directions were 1.52, 0.9
and 2.25 mm, respectively. Finally, we evaluated data related to the uncertainty of COMBIFIX as a device for the radiotherapy delivering. Globally, fromthe intra- and inter-fraction displacements documented, the COMBIFIX cancauses a mean error of 1.2 mm in RL, 0.82 in SI and 1.27 in AP directions.
Conclusions: Our data are similar to those published in the literature related
to set-up errors based on bone anatomy. Most common displacements occur
in RL and AP directions. The PTV margins defined at our department arelarger enough to deliver the treatment safely. Our purpose is to evaluate theorgan motion by using implanted radioopaque markers.

THE ESTIMATION OF REPRODUCIBILITY OF PATIENTS’ IRRADIATION BASED ON DOSE DISTRIBUTIONS MEASURED USING THE
EPID SYSTEM
M. Kruszyna1 , M. Litoborski1 , S. Adamczyk1
1

G REATER P OLAND C ANCER C ENTRE, Medical Physics Department,
Poznan, Poland
Purpose: The aim of this work was to estimate reproducibility of patients’irradiation with the IMRT technique based on changes of dose distributions
which were obtained during treatment using the electronic portal imaging device (EPID).
Materials: The images were acquired daily for 20 patients treated for cancerof the pelvis (P) and head and neck (H&N) regions (total number of collected
images: 3628). Patients were positioned using the EPID system before atreatment session, on average once per week. Images, which were measured
during the first sessions for each subfield, were accepted as the reference fluency maps. All measured images were compared to proper reference maps
using the gamma evaluation method (criteria: DTA 3 mm, DD 3%). Score
value was defined as the quotient of the number of points which have not met
the set criteria to the total number of analysed points. Statistic analysis was
performed using Spearman correlation (p<0.05 is statistic significance).
Results:

S 514MC DEVELOPMENTS

IMRT: T REATMENT VERIFICATION AND QAResults of the score value were examined individually for each patient in respect of variability of particular subfields and repeatability of irradiation of patients (example of reproducibility of H&N patient is presented on graph 1). For
patients, there is a correlation between a median score for each subfield andresults of the pre-treatment IMRT verification: mean gamma (H&N: p=0.000;
P: p=0.001), score value (H&N: p=0.000; P: p=0.100). There is a correlation
between median score for each field and its size (for both H&N, P: p=0.000)
and time of radiation (H&N: p=0.007, P: p=0.000). 83.9% (H&N) and 74.3%(P) of all examined fields have score values below 1%. 95% of all obtained
data have score values below 3.40% (H&N) and 2.88% (P). There are someresults of score value over 5%: 2.7% (H&N) and 1.1% (P). For each region,
the mean score value and standard deviation were determined: the pelvis(0.786±1.046 [%]); head and neck (0.720±1.552 [%]).
Conclusions: Difficulty of repeatable patients’ irradiation depends on resultsof pre-treatment verification, field size, and time of treatment. Generally, repeatability of patient irradiation for the pelvic region was worse than for thehead and neck region because of immobilization of patients. This method
can provide an additional, non-invasive information about daily correctness ofpatient treatment.
1381 poster
TREATMENT VERIFICATIONS IN IMRTS. Narayanan1 , G. Narayanan2
1

V YDEHI I NSTITUTE OF M EDICAL S CIENCES & R ESEARCH C ENTRE,
Department of Medical Physics and Radiation Safety, Bangalore, India
2
V YDEHI I NSTITUTE OF M EDICAL S CIENCES & R ESEARCH C ENTRE,
Radiation Oncology, Bangalore, India
Purpose: Owing to the technological evolution, its now possible to have dose
painting confining to the target volume through Intensity Modulated Radiation
Therapy (IMRT). These complex treatments require high degree of Quality
Assurance, which would ensure precise dose delivery to the intended volume. Number of QA tools is available to carry out pre-treatment verifications.
Though this verification validates the IMRT delivery, it is quite relevant andimportant to verify and validate the performance of the IMRT during actual
treatment delivery.
Materials: We at our Institute have a multi modality modern linear
accelerator$ , capable of delivering IMRT using 120 leaves millennium Multi
Leaf Collimator (MLC). Ten IMRT plans were considered for this study. With
the aid of Portal Dosimetry under ARIA environment$ , each plan has undergone pre-treatment verification for Gamma evaluation and dose difference
between predicted and acquired IMRT fluence, in addition to performing film
dosimetry (using EDR2 film) and absolute dosimetry (using 0.6cc ion chamber) wherever indicated. Argus Dosimetry$ was employed to verify the performance of IMRT during delivery. This QA software helps to evaluate theleaf position accuracy during each delivery segments of IMRT, in addition toevaluating the Gamma and dose difference, for the delivered IMRT fields.
($ Varian Medical Systems, Inc. Palo Alto, CA).
Results: The portal dosimetric review workspace, used for pre-treatment verification, of the fluence match between predicted and acquired IMRT fluence
for the individual treatment fields satisfies the set requirement of 3% and/or
3mm for Gamma evaluation. The treated fields were evaluated through Argus
dosimetry showed good agreements (against the set value) for leaf position
accuracy, evaluated through dynalog files and other dosimetric parameters.
However there were some warning and fail leaf position levels observed forsome of the IMRT plans containing sub fields, though these sub fields did notshow any significant deviation in Gamma evaluation. The leaf position accuracy estimation through Argus is a clear indicator on the performance of theparticular leaf in the MLC assembly.
Conclusions: The performance evaluation of IMRT during actual treatment
enhances confidence level of IMRT delivery system, which had satisfactory
pre-treatment verification. Argus QA software is a viable and reliable dosimetric tool to validate IMRT delivery, in addition to the traditional QA tools.
1382 poster

VALIDATION OF 3DVH SOFTWARE FOR USE IN PATIENT SPECIFICIMRT QUALITY ASSURANCE
M. Nielsen1 , M. Carlone1 2 , C. Cruje1 , M. MacPherson1 2
1
C ARLO F IDANI P EEL R EGIONAL C ANCER C ENTRE, Department of Medical
Physics, Mississauga, Canada
2
P RINCESS M ARGARET H OSPITAL AND U NIVERSITY OF TORONTO,
Radiation Medicine Program, Toronto, Canada
Purpose: Patient specific IMRT quality assurance typically compares dose
distributions measured and calculated in-phantom. The clinical importanceof any disagreement between measured and calculated dose is often difficult
to interpret. Recently, software has been developed (3DVH Sun Nuclear,
Florida USA) that calculates the "delivered" dose distributions in patients byperturbing the calculated dose using errors detected in fluence or planar dose
measurements. The aim of this work was to validate the accuracy of 3DVH

versus commercial treatment planning software (Varian Eclipse 8.9).
Materials: 17 DMLC prostate IMRT treatment plans were exported as
DICOM-RT datasets from the planning system. A Matlab script was used tomodify the planned MLC positions, introducing randomly distributed positional
errors of 0 to 3 mm while maintaining deliverability at the linear accelerator.
The MLC modifications were saved as new DICOM-RT Plans. These modified plans were delivered to a 2D diode array (MapCheck2, Sun Nuclear),for a total of 357 measured dose planes. Measured doses were comparedto the dose planes from the original plan and dose differences used as input
to 3DVH to calculate a "delivered" dose in the patient. For comparison, themodified DICOM-RT plans were re-imported into the planning system andthe expected dose distribution in the patient was calculated. DVH comparisons were made based on mean dose and D99 for the PTV, and mean andmaximum dose for the bladder wall and rectal wall for each patient and MLC
error.
Results: Paired Data showed good agreement for planning system and3DVH dose volume histograms for both targets and organs at risk for bothmodified and unmodified plans, regardless of MLC error induced. Structuremean dose values as measured for PTV, Bladder wall and Rectal wall agreed
to within 1% (σ =1.5%) and dose maximum data showing a discrepancy of
2% (σ =2%).
Conclusions: 3DVH is a useful tool to calculate delivered dose distributions
during patient specific IMRT quality assurance. The 3DVH data allows theuser to analyze the difference between planned and delivered dose to given
structures. By introducing random delivery errors, we showed that the 3DVH
software was able to detect small fluence changes. This demonstrates theaccuracy of 3DVH software against a commercial treatment planning system.
1383 poster
VERIFICATION DOSIMETRY FOR LUNG SBRT VMAT
J. Lilley1 , S. Derbyshire1 , V. Cosgrove1 , C. Thompson1 , D. I. Thwaites1
1

S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom

Purpose: VMAT has already been clinically implemented at SJIO for prostate
treatments, using the RayArc VMAT optimiser in Oncentra MasterPlan v3.3
(Nucletron), and an Elekta Synergy with an MLCi2 head. We now intend touse VMAT for NSCLC SBRT applications. Currently, we treat up to 8 patientsa month with SBRT and have treated over 80 patients by December 2010.
A 7-9 field, conformal technique is used with either 54Gy in 3 or 55Gy in 5
fractions. Patients are treated using a midline-isocentre, off-axis technique to
avoid potential collision between the immobilisation devices and the gantry,
allowing full gantry rotation during XVI image acquisition. An initial VMAT
planning study was performed with plan quality assessed using the conformity indices and OAR constraints as defined in the UK SBRT consortium
guidelines.
Materials: VMAT plans were compared with the current clinical techniqueas well as the consortium guidelines. Test plans were delivered using 6MV
beams from an Elekta Synergy,using Desktop v7.0 and Mosaiq v1.6. Verification dosimetry measurements were carried out as part of a pre-clinicalcommissioning programme, using a Semiflex ionisation chamber (0.125cm3 )and an Exradin A16 Microchamber (0.007cm3 ). All plans were calculatedwith the OMP collapsed cone algorithm. To understand the sources of dosimetric uncertainties associated with the VMAT SBRT delivery, measurements
were compared to the dose calculated in OMP with increasing levels of complexity. The simplest being a measured dose at depth at the isocentre for a
3x3cm field incident on a flat surface, and the most complicated being thedose measured at the centre of the PTV in a CIRS lung phantom using a
midline isocentre technique.
Results: SBRT VMAT plans fulfilling the dose requirements were achieved.
The SBRT delivery was also much quicker than standard conformal plans,with an 11Gy fraction beam on time reducing from 450sec to 300sec. Someof the results of the dosimetric measurements compared with calculated areshown in figure 1. All were measured with a semiflex chamber except whereindicated with the A16.

S 515

to beam hardening as a function of phantom thickness strongly depends on
the HA concentration. It is about 7.5% for HA200, 15% for HA400 and 20%
for HA800. The same relative decrease was found with or without taking into
account contributions from different scatter components.
Conclusions: Using the MC model of the XTremeCT CBCT, different contributions of its detector response can be separated and analyzed in orderto understand the limitations of the detection and the resulting image quality.
This work was supported by CTI and SCANCO Medical AG.
1385 poster
COMMISSIONING OF PENELOPE AND GATE MONTE CARLOMODELS FOR 6 AND 18 MV PHOTON BEAMS FROM THE SIEMENSARTISTE LINAC
D. Lazaro-Ponthus1 , L. Guérin2 , A. Batalla2 , T. Frisson3 , D. Sarrut3
1
CEA LIST, Gif sur Yvette, France
2
C ENTRE F RANÇOIS B ACLESSE, Caen, France
3
U NIVERSITÉ DE LYON ; CREATIS ; CNRS UMR5220 ; C ENTRE L ÉON
B ÉRARD, Lyon, France

Conclusions: VMAT SBRT for lung presents particular challenges for accurate dosimetry as it involves very small fields rapidly changing in shape withintissue where there are large density inhomogeneities. There are many factorsthat influence the accuracy of the dose measured compared to calculated, including MLC leaf calibration, accuracy of chamber positioning, and phantom
constituents. The results presented here indicate that when simple, small
phantoms are used then the dosimetric results obtained are within tolerance
but as the measurements are moved to larger more complex phantoms theresults move beyond acceptable limits. The semiflex chamber gave very similar results to the much smaller A16 chamber. Further work is required tounderstand and resolve the remaining uncertainties before this technique isused clinically.

MC developments
1384 poster
ANALYSIS OF THE DETECTOR RESPONSE FOR CT USING MONTECARLOW. Volken1 , M. Fix1 , D. Frei1 , M. Zulliger2 , P. Manser1
1
I NSELSPITAL , U NIVERSITÄT B ERN, Division of Medical Radiation Physcis,
Inselsptial - University Bern, Switzerland, Bern, Switzerland
2
SCANCO M EDICAL AG, Brüttisellen, Switzerland
Purpose: The aim of this work is to investigate the detector response of a
micro cone beam CT (CBCT) scanner equipped with a high-resolution CsI
scintillator detection device using Monte Carlo (MC) methods.
Materials: In this study the detector response of the XtremeCT CBCT scanner (SCANCO Medical AG) was simulated using the egs++ MC code in order
to explore the dependency of the detector response from various scatter components. The detector response is a complicated conjunction of different processes the X-rays undergo mainly in the phantom and in the detector itself.
Slab phantoms with various thicknesses from 0.5 to 8 cm and different material compositions were used. The slab materials consisted of a mixture of
epoxy resin with hydroxyapatite (HA) concentrations of 200 mg/cm3 (HA200),
400 mg/cm3 (HA400) and 800 mg/cm3 (HA800). Two types of detector response point spread functions (PSFs) were derived from pencil beam simulations: The contribution to the PSF from particles scattered in the phantom,
called the phantom-PSF, and the detector response PSF from particles scattered in the detector only, called the detector-PSF. In addition, broad beamsimulations of these slab phantoms were performed to investigate the impact
of beam hardening (BH) on detector response. To estimate the blurring due
to different scatter components, slab shaped edge phantoms with a sharp
HA-water inhomogeneity were simulated as a function of slab thickness and
HA concentration.
Results: The fraction of the energy response for the detector-PSF outside
the central pixel (0.7 x 0.7 mm2 ) is about 5% of the total absorbed energy
and is deposited within a radius of 1.4 mm around the incident position of
the pencil beam. It depends weakly on the phantom material and phantom
thickness. In contrast the phantom-PSF depends strongly on phantom thickness and composition. The fraction of its energy response outside the central
pixel is 1-7% for HA200, 1-9% for HA400 and 1-12% for HA800 of the total absorbed energy and is distributed across the whole detector area (17 x
1.4 cm2 ). Ideally of the edge phantom would lead in a step-shaped detector response. The short range of the detector-PSF degrades this step locallyaffecting the nearest neighbor pixels. In contrast, the phantom-PSF leads towide range blurring of the detector signal but degrades the gradient less compared to the detector-PSF. The relative decrease of the detector response due

Purpose: Monte Carlo (MC) simulations currently allow accurate calculationof the dose delivered to patients in radiotherapy treatments, provided thatthe linear accelerator can be modelled accurately. The commissioning of thelinac model is thus an important task to ensure the overall accuracy of the calculated dose. This work aims at commissioning MC models developed with
PENELOPE and GATE for the 6 and 18 MV photon beams of the Siemens
ARTISTE linac, by comparing simulation to measurement.
Materials: Linac photon beam models at 6 and 18 MV were commissioned.
Percentage depth doses (PDD) and lateral beam profiles at dmax, 5 and 10
cm were measured for open square fields from 5x5 to 30x30 cm at 100 SSD
using a PTW large MP3 water tank with a PTW Semiflex 0.125 cm3 ionizationchamber. MC simulations were performed using PENELOPE 2006/PENFAST
and GATE v6.0 (based on GEANT4 9.3.p02) in two steps: phase space files
storing particles exiting the linac head were first computed and then used as
input data for dose computation. Both codes are optimized for radiotherapy
purposes and include commonly used variance reduction techniques. The
linac geometry was described in the simulation based on the manufacturer
specifications. The main parameters defining the incident electron beam, i.e.
its mean energy and its radial intensity distribution, were determined following the methodology suggested by Pena et al (Med. Phys. 2007), using
PDDs and lateral profiles of the 5x5, 10x10 and 30x30 cm fields. The incident electron beam was assumed to be monoenergetic and monodirectional.
Dose computations in the water phantom were performed using PENFAST
and GATE 6.0.0, with a voxel size of 4 mm in all directions for all field sizes.
Results: At depth greater than dmax, simulated PDDs with GATE and PENELOPE both agreed with measurement to better than 1% for 6 and 18 MV. At
shallower depths, both MC codes underestimated the measured dose. Lateral profiles matched measured ones within 1%/1 mm at 6 MV and within
2%/2 mm at 18 MV, for both codes. Larger discrepancies are however observed for field sizes larger than 25x25 cm. Work is ongoing to identify thereasons for these discrepancies; the impact of the initial electron energy distribution is particularly investigated.
Conclusions: Photon beam models of the Siemens ARTISTE linac at 6 and
18 MV were developed with PENELOPE and GATE and commissioned. Goodagreement was obtained between measured and simulated dose distributions, confirming the validity of the models.
1386 poster
CTCASK; A NEW ALGORITHM FOR CONVERSION OF CT TO
TISSUE PARAMETERS FOR MONTE CARLO DOSE CALCULATIONS
R. O. Ottosson12 , C. F. Behrens1
1
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Oncology,
Herlev, Denmark2
R ISØ N ATIONAL L ABORATORY FOR S USTAINABLE E NERGY, T ECHNICALU NIVERSITY OF D ENMARK, Roskilde, Denmark
Purpose: One of the building blocks in Monte Carlo (MC) Treatment Planning is to convert CT numbers to a MC compatible phantom, consisting of adensity and a material matrix. Traditionally this is done by dividing the CTdata into bins corresponding to materials and subsequently applying a linear
interpolation of density within each bin. This protocol is limited to a single,
global, material binning scheme. This can potentially lead to erroneous material and/or density assignment and ultimately an error in dose. The purposeof this study was to develop a new algorithm, enabling locally confined conversion.
Materials: A MATLAB program, called CTCask (CT Create Applying DICOMRS Knowledge), was developed. The CT data is globally converted to density
using a continuous partially linear function. Each pre-delineated structure in
the DICOM data-set can be assigned different material constraints and thematerial conversion is conducted individually for each structure. Finally theindividual material matrices are combined to a single material matrix. The
new algorithm was benchmarked against the DICOMRT toolbox. Material

S 516MC FOR DOSIMETRY AND QAMC FOR B RACHY

assignment and MCSIM-dose calculation was compared for 6 cases. The
following materials were considered; AIR, LUNG, TISSUE, BONE for case1 through 4, while for case 5 and 6 LUNG was omitted. In CTCask, eachstructure was allowed to use only those materials that are likely to be foundwithin that structure. Only voxels inside the external contour were considered.
For the dose comparison voxels with uncertainty larger than 2% were ignored.
Results: The methods disagreed in material assignment for 0.19 to 2.10%of the voxels (Table 1). The 2.10% difference for case 1 was partially due toa contrast enhancing agent. The traditional method, erroneously, assigned
a majority of the heart with bone. This was completely avoided while using
CTCask. In terms of dose a range of 0.09 to 5.60% of the voxels in playdiffered by more than 5%. The share of voxels differing by more than 5%increased for all cases when considering dose to water as oppose to dose to
medium.

Conclusions: It is now possible to manage routine multi-step computations
involving "BEAMnrc" and "DOSxyznrc" with minimal exposition to errors andwith user interaction reduced to an absolute minimum. Thus the new utility
allows the user to concentrate more on the core problems of his or her work
while almost entirely liberating him or her from the burden of managerial tasks
inherent to complex calculation workflows. Furthermore, the utility presented
here is programmed in a rather simple fashion what makes it adaptable to awide range of specific problems.

MC for Brachy
1388 poster
DOSIMETRIC STUDY OF THE 103-PD EYE PLAQUE
P. Saidi Bidokhti1 , M. Sadeghi2 , A. Shirazi3 , S. R. M. Mahdavi4 , M. Mirzaii5
I SLAMIC A ZAD U NIVERSITY [S CIENCE AND R ESEARCH B RANCH ], Tehran,
Iran Islamic Republic of
2
AGRICULTURAL , M EDICAL, Radioisotopes, Karaj, Iran Islamic Republic of3
T EHRAN U NIVERSITY OF M EDICAL S CIENCE, Medical Physics, Tehran, Iran
Islamic Republic of4
I RAN U NIVERSITY OF M EDICAL S CIENCES, Medical Physics, Tehran, Iran
Islamic Republic of
5
AGRICULTURAL , M EDICAL, Cyclotron Unit, Karaj, Iran Islamic Republic of
1

Conclusions: A new method for conversion of CT data to MC phantom was
successfully developed. Adding more materials further demonstrate the advantage of CTCask; the possibility of using materials with similar densities
but with distinct locations (e.g. breast and liver). Moreover, CTCask enables
assigning air with zero density to all voxels outside of the body outline, thus
emulating the scenario of a treatment planning system.
1387 poster
GLAUNCHER - A UTILITY FOR AUTOMATIZATION OF ROUTINE,
MULTI-STEP WORKFLOWS INVOLVING MONTE CARLO CALCULATIONS WITH "BEAMNRC" AND/OR "DOSXYZNRC"
P. Adrich1
1
T HE A NDRZEJ S OLTAN I NSTITUTE FOR N UCLEAR S TUDIES, Accelerator
Physics and Technology Dpt, Otwock-Swierk, Poland
Purpose: To create a user-friendly utility facilitating management of routine,
multi-step Monte Carlo calculations involving "BEAMnrc" and "DOSxyznrc"
such as those encountered in e.g. design studies of electron beam shaping
systems of linear accelerators.
Materials: The programming was done in Tool Command Language (Tcl)
with the Tk graphics widget library used to create a graphical user interface(GUI). The workflow management relies on capabilities of the Portable Batch
System (PBS).
Results: The new utility features a single screen GUI reflecting a workflow
typically encountered while working on e.g. electron beam shaping system ofa linear accelerator. With a few mouse clicks a user can initialize executionof a complex flow of calculations that would otherwise require a rather time
consuming and error-prone sequence of interactions with a number of programs. The user is only required to supply minimum input information while
GLauncher takes care of all that needs to be done to obtain plots of normalized depth-dose and off-axis profile. In addition the software automaticallyanalyzes resulting dose distributions and extracts a number of basic quantities, e.g. depth of dose maximum, practical range, flatness of the profile,etc. The software is capable of bypassing the 80 characters filename length
limit hardwired in "BEAM", as well as, of handling parallelized calculations
including cleaning after such calculations.

Purpose: Brachytherapy dose distributions are calculated for Stainless steel
eye plaque loaded with the IRA1-103 Pd brachytherapy seeds. The effectsof stainless steel backing and Silastic insert on dose distribution along thecentral axis of the eye plaque and at critical ocular structure are investigated.
Materials: Monte Carlo simulation was carried out with the Version 5 of the
MCNP. IRA1-103 Pd seeds were distributed in to 15 mm Stainless steel eye
plaque. Additional MC calculations were performed, where the Silastic insert and stainless steel are replaced with water. The dose at critical ocular
structure by considering the eye composition was calculated. Results arecompared with the calculated data for COMS eye plaque loaded with Theragenics200 palladium-103 seeds and model 6711 iodine-125 seed.
Results: The calculated dose rate constant of the IRA1-103 Pd seed wasfound to be 0.677±0.020 cGyU-1 h-1 . Air kerma strength to deliver 85 Gy inapex of tumor in water medium was calculated to be 4.10 U/seed. Along thecentral axis of stainless steel plaque loaded with new 103 Pd seeds in Silastic
insert, the dose reduction relative to water is about 17% at 5 mm (apex). On
the plaque central axis at 1cm, the presence of the Silastic alone, decrease
the dose by the order of 15%. The stainless steel backing results in doseenhancement near the plaque relative to water.
Conclusions: The dosimetric parameters calculated in this work for the
IRA1-103 Pd seed, showed that in dosimetry point of view, the seed is suitable for use in brachytherapy. The dose distribution in the eye region for the103
Pd seed is calculated. The main effect on dose reduction is due to thepresence of Silastic insert.
1389 poster
MONTE CARLO SIMULATION OF A HIGH DOSE RATE GYNECOLOGICAL BRACHYTHERAPY TREATMENT TAKING INTO ACCOUNTTHE HETEROGENEITY OF THE PATIENT
R. Berenguer1 , M. Rivera1 , A. T. Nunez Quintanilla1 , V. de la Vara Olivas1 ,M. Gutierrez1 , S. Sabater1
1
H OSPITAL G ENERAL DE A LBACETE, Radiotherapy Department, Albacete,
Spain
Purpose: The aim of this study was to compare the dosimetric distribution ofa gynecologic brachytherapy treatment with high dose rate Ir-192 source asa conventional treatment planning system (TPS) does versus the dosimetric
distribution obtained by Monte Carlo simulation taking into account (in addition to the geometry of the source) the gynecological vaginal applicator (tubeand vaginal cylinder or dome) and the anatomy of the patient. In particular we
focused on the effect of iodinated contrast within the bladder of the patient.
Materials: Monte Carlo simulation was performed using PENELOPE2008.1
code, and module penEasy (v.2010-09-07). We used this code because it has
the package of subroutines "penVox" that allows the simulation of a geometry
defined by quadrics and voxels simultaneously. First of all, a brachytherapy
gynecological treatment was simulated taking into account only the geometryof the high dose rate source of Ir-192 v2 (Nucletron) in quadrics mode andsurrounded by water voxels; afterwards, that source and the gynecologicalvaginal applicator (tube and cylinder) were simulated in quadrics mode surrounded in this case by voxels of different human tissues obtained from theCT of the patient from a conversion table (CT number versus relative electron density and tissue-type). In both cases, the quadrics geometry perfectly
adapted to the position of the objects on the CT scan of the patient.
Results: The comparison of the dosimetric distributions of both simulations
shows two differences: first of all is the additional attenuation caused by thepresence of vaginal applicator tube not considered in conventional TPS; secondly, the existence of iodinated contrast in the bladder, as routinely is performed in our center, causes a major change in the dosimetric distribution.
The simulation results show that the absorbed dose in the bladder was approximately doubled. The figure shows the ratio of the absorbed doses between the two simulations (calculated with the heterogeneity and without)superimposed on the CT slice. All the studies found in the literature haveshown no significant differences in gynecological brachytherapy treatments
when taking into account the heterogeneity of the patient because the presence of bone, muscle, etc does not alter significantly the dosimetry. However,iodinated contrast itself significantly alters the distribution, a fact that has been
proven in other locations such as in the case of MammoSite®. On the other
hand, a question arises when comparing absorbed dose to "water" as calculated by TPS versus absorbed dose in "human tissues" as calculated byMonte Carlo codes generally. To avoid this problem a conversion from absorbed dose in tissue to absorbed dose in water was applied using the massenergy absorption coefficient ratios taking into account the energy spectrum
that reaches the bladder. The results did not show a very significant influencein this case.

Conclusions: The results of this study demonstrate that the presence of
iodinated contrast in the bladder significantly modifies the dosimetric distribution of a brachytherapy gynecological treatment with a high dose rate Ir-192
source by increasing the absorbed dose to the bladder.Acknowledgments:
We would like to thank Dr. Josep Sempau Roma, researcher at the Institute of Tiques Energetiques of the Universidad Politica de Catalunya for his
invaluable contribution to this work.

S 517

cornea, bulbar conjunctiva, retina and papilla. Furthermore, the eye has been
divided into two hemispheres, anterior and posterior globe, that can be evaluated separately. The only structure in the orbit that has been segmented inthis model is the lachrymal gland.
Conclusions: By means of MC simulation combining eye plaques and CT
geometries it is possible to obtain, for the first time, a realistic estimation of
the dose distribution to defined anatomical structures in the eye when treating
eye tumours with a Ru/Rh-106 plaque. This opens a door for optimising thedesign of innovative plaques.
1391 poster
PATIENT SPECIFIC MONTE CARLO DOSE CALCULATIONS OF
HIGH-DOSE-RATE BRACHYTHERAPY OF PARTIAL BREAST
IRRADIATION
D. Terribilini1 , B. Isaak1 , P. Manser1 , D. Frei1 , W. Volken1 , R. Mini1 , M. K.
Fix1
1U NIVERSITY H OSPITAL , I NSELSPITAL B ERN, Division of Medical Radiation
Physics, Bern, Switzerland
Purpose: For high dose rate (HDR) treatment plans the TG43 formalism iscommonly used for patient dose calculations. However, dose distribution perturbation factors such as patient outline, inhomogeneity and applicator shielding are ignored in this formalism. To analyze the impact of these factors todose distribution, the Swiss Monte Carlo Plan (SMCP) environment has been
extended to HDR brachytherapy dose calculation of treatment plans. In thiswork, the influences of patient geometry and heterogeneities on dose distributions of HDR brachytherapy of partial breast irradiation have been studied.
Materials: 10 HDR treatment plans of partial breast irradiation previously calculated according to the TG43 formalism have been recalculated within the
SMCP environment. For this purpose, patient data (DICOM CT) as well asplan data (DICOM RP) have been exported from the treatment planning system (TPS) via DICOM export. With the exported CT slices and a customized
conversion curve (physical density vs. HU), a voxel phantom is generated,
where coordinates, composition and density of each voxel are stored. Source
positions, treatment times as well as the total reference air kerma (TRAK) are
extracted from the exported DICOM patient plan. The TRAK is used for thenormalization of the calculated dose distributions. Dose distributions calculated according to the TG43 formalism report absorbed dose to water, while
MC dose distributions are expressed in dose to medium. For dose calculation comparisons, dose distributions calculated with MC have been converted
to dose to water. Dose-volume parameters (VDref, V1.5xDref, DPTV,50%,
DSkin,0.5ccm) as well as quality indices (DNR, DHI, CI) of the plans generated with TG43 and MC have been determined and compared.
Results: Dose calculations based on TG43 overestimate VDref and
DPTV,50% as compared to the MC calculations in the range of 3% to 5%
and ~6%, respectively. By taking into account the lack of scattering volume at
the skin surface in the MC calculations 4% to 6% lower maximal skin doses(DSkin,0.5ccm) are observed compared with TG43 based calculations.
Conclusions: The MC-based brachytherapy dose calculations within the
SMCP highlighted limitations in dose prediction of today’s treatment planningsystems, based on the TG43 formalism, for HDR brachytherapy of partial
breast irradiation.

1390 poster
MONTE CARLO SIMULATION OF RU/RH-106 EYE PLAQUES ON A
MIXED QUADRIC AND VOXELISED GEOMETRY
L. Brualla1 , D. Fluehs1 , A. Wittig2 , N. Bornfeld3 , W. Sauerwein1
1
U NIVERSITÄTSKLINIKUM E SSEN, Strahlenklinik, Essen, Germany
2
K LINIKUM DER P HILIPPS -U NIV. M ARBURG, Department of Radiation
Oncology, Marburg, Germany
3
U NIVERSITÄTSKLINIKUM E SSEN, Ophthalmology, Essen, Germany
Purpose: High energy electrons resulting from the beta-decay of Ru/Rh-106
are routinely used to treat eye tumours. The evaluation of the spatial distribution of these electrons and the resulting absorbed dose distribution in an eye
are challenging tasks for a medical physicists. Monte Carlo (MC) may provide
a solution to overcome this problem. However, up until now only a few MC
simulations of dose distributions produced by Ru/Rh-106 eye plaques havebeen done. In all published works the eye is modelled as a homogeneous
sphere with a filling material which is usually water. Such approach, althoughis quite accurate from the radiation transport point of view, disregards theanatomical structure of the eye. In the present work a more realistic approachto this problem is proposed.
Materials: The MC code PENELOPE with the main program penEasy wereused to simulate a Ru/Rh-106 eye plaque. The main program needed to bemodified in order to simulate primary electrons according to the continuous
beta-decay energy distribution of Rh-106. penEasy allows for the simulationof mixed quadric and voxelized geometries, so the eye applicator has beenmodelled with quadric surfaces and inserted in voxelised computer tomography (CT) of an eye.
Results: The CT image has been segmented, so dose volume histograms(DVH) for the following anatomical structures of the eye have been obtained:

MC for dosimetry and QA
1392 poster
COMPARATIVE PROSTATE MOVEMENT ASSESSMENT WITH GOLD
MARKERS AND BONY ANATOMY USING CONE-BEAM COMPUTEDTOMOGRAPHY IMAGES
X. J. Juan-Senabre1 , J. Lopez-Tarjuelo1 , A. J. Conde-Moreno2 , A. L.
Sanchez Iglesias2 , A. Santos-Serra1 , J. D. Quirós-Higueras1 , N. deMarco-Blancas1 , C. Ferrer Albiach2 , S. Calzada-Feliu1
1
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Department ofMedical Physics and Radiation Safety, Castelló de la Plana, Spain
2
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Radiation
Oncology Department, Castelló de la Plana, Spain
Purpose: To asses the prostate motion using 3D-3D registration images
based on kilovoltage cone-beam computed tomography (CBCT) and analyze
the setup and internal motion uncertainties comparing two matching methods; gold fiduciary markers as prostate surrogate and bony anatomy targeting.
Materials: Daily kV CBCT images was acquired during treatment process.
Three fiduciary gold markers were implanted on the prostate of 22 patientswith prostate cancer stage T1-3N0M0. All patients are treated following a
non-flatulent diet, full bladder, empty rectum, pillow under knees and footrest.
Axial CT slices of the pelvis at 10 mm thickness were acquired and reconstructed each 3 mm. The 5 first fractions double CBCT was acquired with

S 518MC FOR DOSIMETRY AND QAMC FOR DOSIMETRY AND QA

online protocol correction, afterwards offline SAL protocol was applied. Using
the first set of CBCT data intrafraction uncertainties (internal motion errors)
are analyzed, and the other set carries out to asses interfraction uncertainties (setup errors). Later, interobserver variation is determined. Throughout
the treatments a non-migration markers procedure is followed. The 3D-3D
registration images use an automatic process bases on grey value criteria,
and finally, if it is necessary, a manual adjustament is made. The study isbased on a comparison of two methods for defining the fusion box; the firstone only includes the gold markers (GM, fig. 1) and the second one part ofthe pelvic bone structures (BS, fig. 2). A total of 1550 CBCT were analyzed
using statistical study for translations and rotations. Setup, internal motion
and interobserver uncertainties were obtained and the CTV to PTV marginusing current recipes for both methods used.

Purpose: The exact configuration of medical linacs is not known accurately
for all Monte Carlo users. Accurate determination of incident beam parameters that impinge on target is very important to obtain accurate results byMonte Carlo N Particles (MCNP).
Materials: In this study, Monte Carlo simulations of several configuration of
the primary electron beam mean energy, beam energy FWHM and spatial
FWHM for a wide range of clinically useful field sizes at SSD=100 cm were
implemented(Table 1). Percent depth dose (PDD) and Beam profile (BP) (atdmax, 5cm and 10cm depths) were calculated and analyzed for each case.
The experimental measurements were performed by using PTW Dosimeter(0.125 ionization chamber) in the water tank (50x50x70 cm3). The best combination is selected by performing a simultaneous comparison with the correspondent measurements for those same fields. This procedure was employed to determine the characteristics of the primary electron beams thatgenerate datasets for a Varian 2100CD 6 & 18 MV accelerator in the MCNP
simulations.

Results: PDDs and Beam profiles of measurements and simulations wereanalyzed for each case. Differences were quantified by Root Mean Square
Error (RMSE) and Gamma index. Best agreement, with less than 3% of an
average difference, between simulations and measurements for a wide rangeof field sizes were chosen to determine electron beam parameters.
Conclusions: Due to ambiguity in source and target definition of medical
Linacs, it’s necessary to determine accurate primary electron beam parameters to apply for Treatment planning system and clinical uses. Furthermore,
Beam profiles should be considered for several field sizes, especially for thoseindividual applications.
1394 poster
Results: The interobserver uncertainty using GM is about three times higher
than the involved one when using BS. The intrafraction study reports a PTV
margin of (2.0, 2.5, 2.4) mm in RL, SI and AP directions for GM; (2.3, 3.2, 2.4)mm in RL, SI and AP directions for BS. The interfraction study concludes a
PTV margin of (4.1, 3.8, 4.8) mm in RL, SI and AP directions for GM; (4.1, 3.3,
4.7) mm in RL, SI and AP directions for BS. Finally the total margin should beapplied taken into account all uncertainties is (4.8, 4.9, 5.6) mm in RL, SI and
AP directions for GM; (4.7, 4.7, 5.3) mm in RL, SI and AP directions for BS(see figs. 3-14, tables 1-2).

Conclusions: Cone-beam CT is an accurate and precise tool for image guidance. The major differences found between both methods were in SI and AP
directions for translations and RL direction for rotations. Fiduciary markers
are useful to assess prostate position and their property as prostate’s surrogate is known, but require an invasive intervention. In this study the use offiduciary markers does not improve the final PTV margin result, being quite
similar in both methods. The explanation maybe is due to the high interobserver uncertainty and the CT parameters acquisition. Therefore BS is aninteresting and simple method to matching 3D images to obtain couch corrections positioning.
1393 poster
DETERMINATION OF PRIMARY ELECTRON BEAM PARAMETERS
IN MONTE CARLO SIMULATION OF MEDICAL LINAC
S. A. Vaezzadeh1 , M. Allahverdi2 , H. A. Nedaie3 , M. Yarahmadi1
1
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Tehran, Iran Islamic
Republic of2
T EHRAN U NIVERSITY OF M EDICAL S CIENCES R ADIATION O N, Tehran, Iran
Islamic Republic of3
T EHRAN U NIVERSITY OF M EDICAL S CIENCES, Cancer Institute, Tehran,
Iran Islamic Republic of

MONTE CARLO DOSE CORRECTION FACTORS DETERMINATIONFOR TOMOTHERAPY BEAM
A. Stravato1 , R. Rauco1 , D. Aragno1 , M. Pacilio1 , M. C. Pressello1 , E.
Santini1
1
A ZIENDA O SPEDALIERA S AN C AMILLO - F ORLANINI, Medical Physics
Department, Roma, Italy
Purpose: The aim is to calculate the correction factors of three ionizationchambers (ICs) for absolute dose determination in TomoTherapy (TT) static
beam directly using Monte Carlo (MC) simulations. According to International
Protocols for dose determination, for a beam of quality Q the energy corrections factor kQ are tabulated vs beam quality index measured in standard
reference conditions. TT machine design does not allow determining beam
quality index in standard reference conditions and in addition the TT beam
is unflattened. As recently proposed for standard beams (Med Phys.37(11)2010), in the present work MC calculations are performed to obtain overallcorrection factors, named here kTT, correcting for both the beam quality andthe non standard irradiation conditions (field size and SSD).
Materials:
TT unit installed in our centre is simulated with the
EGSnrc/BEAMnrc MC code. Our model of the accelerator head starts fromthe phase spaces files placed below the Y jaws and incident on the multileaf collimator and the lead collimator component modules. The available Y
fields are 1x40, 2.5x40, 5x40 cm2 . The acceptance criteria for relative profiles are 3%/3mm verified with a 1D gamma function. Dose value agreement
is also verified using TPR20,10 calculation performed in TT reference conditions (5x10 cm2 field size, SDD=85 cm). The discrepancy is within 1.6%.
Pin Point PTW 31016, Exradin A1SL Standard Imaging, Farmer PTW 30013
ICs are simulated with EGRSnrc user-code egs_chamber, starting from thetechnical details provided by manufacturer sheets. The ICs are calibrated
by primary standards laboratories in terms of the absorbed dose to waterin a Co60 beam. The egs_chamber simulations are first verified against
TPR20,10 measurements in the same set-up previous described, reachingan agreement of 1.1%. The dose-to-air scored in the chamber cavities andthe dose-to-water in absence of the dosimeter, are calculated together with
its ratio. The correction factor kTT for the TT reference conditions (5x10 cm2 ,SSD=85cm) related to a Co60 beam (10x10 cm2 field SSD=100cm) is calculated for each ICs.
Results: The kTT values are calculated for the three chambers. They arecompared with the experimental ones obtained applying the new formalism
proposed by Alfonso et al (Med. Phys. 35(11) 2008) and with the analyticalmethod introduced by Thomas (Med. Phys. 32(5) 2005) according to the TG
148 (Med. Phys. 37(9) 2010). Here only the result for the A1SL is reported.
A kTT, value of 0.997 is found from the simulation. It differs within 0.3% fromthe experimental data (submitted) and 0.2% from the analytical one.
Conclusions: For TT unflattened beam in non standard geometry irradiation
the corrections factors kTT for dose determination may be directly calculated

by MC simulations. Results for three cylindrical ICs for TT static beam arereported and compared with literature data.
1395 poster
MONTE CARLO SIMULATION OF TRANSIT DOSIMETRY WITH A
DIRECT DETECTION A-SI EPID IN 6 MV TREATMENT BEAMS
M. Sabet1 , B. McCurdy23 , Z. Kuncic4 , F. Menk1 , P. Greer51
1
T HE U NIVERSITY OF N EWCASTLE, Maths and Physical Sciences,
Newcastle, Australia
2
T HE U NIVERSITY OF M ANITOBA, Winnipeg, Canada
3
C ANCER C ARE M ANITOBA, Winnipeg, Manitoba, Canada
4
T HE U NIVERSITY OF S YDNEY, Sydney, Australia
5
C ALVARY M ATER N EWCASTLE H OSPITAL, Radiation Oncology, Newcastle,
Australia
Purpose: Modification of a-Si EPIDs to direct detection configuration has
shown great promise for patient dose verification. The aim of this study is todevelop a Monte Carlo model to simulate transit dosimetry images acquiredby an a-Si EPID in direct detection configuration to make quantitative comparisons between measured and simulated portal images.
Materials: The BEAMnrc module of EGSnrc was used for the simulation ofa Varian Clinac 21EX linac. A Varian aS500 EPID was modified to direct detection configuration (by removal of the phosphor screen and all layers above
the detector except a black sheet of paper to block the ambient light) andmodelled using the DOSXYZnrc module of EGSnrc. Doses were scored in
the glass layer. The EPID model was evaluated by comparing the measured
and simulated output factors and image profiles in in-plane and cross-plane
directions. After validation of both the linac head and EPID models, they wereused to simulate a variety of transit dosimetry conditions (different buildups,
air gaps, field sizes and phantom thicknesses) and the results were assessed
relative to measurements made with the direct EPID by comparing the profiles (normalized to the centre) and relative EPID response at the central 1
cm2 area.
Results: The direct EPID model agreed with the measurements in in-planeand cross-plane directions within 1%. The measured and calculated output
factors agreed within 1% except for the largest field where the difference was
1.5%. Comparison of the various transit dosimetry conditions showed thatthe measured and modelled profiles agreed within 3% in all cases and therelative EPID response at the central 1 cm2 agreed within 2% for all conditions
studied.
Conclusions: As our model has shown good agreement with measurements,
it can be confidently used as an accurate tool to predict the transit dose fordirect EPIDs in open fields. This study suggests that in-vivo dosimetry witha water-equivalent EPID can be a practical alternative to the application ofcomplicated corrections to standard EPIDs.
1396 poster
ON THE DOSIMETRIC CHALLENGES OF DYNAMIC JAWS TOMOTHERAPY: A MONTE CARLO STUDY.
E. Sterpin1 , Y. Chen2 , Q. Chen2 , W. Lu2 , T. Mackie32 , S. Vynckier4
1
U NIVERSITÉ C ATHOLIQUE DE L OUVAIN, Medical Physics, Louvain-laNeuve, Belgium
2
TOMOTHERAPY I NC, Madison, WI, USA
3
U NIVERSITY OF W ISCONSIN, La Crosse, USA
4
U NIVERSITÉ C ATHOLIQUE DE L OUVAIN, Louvain-la-Neuve, Belgium

Purpose: In its present configuration, tomotherapy uses three fixed different
field widths (5, 2.5 and 1 cm), limiting the control of the longitudinal modulation. This can be overcome by allowing the jaws to move dynamically. The
goals of this study are : 1) describe the implementation of the dynamic jaws
feature in TomoPen, a Monte Carlo (MC) based model; 2) provide a detailed
knowledge of the dosimetric issues with small field deliveries including output
factors and potential linac displacements.
Materials: TomoPen includes now efficient arbitrary jaw openings (Sterpin
et al 2010, Radiother. Oncol. 94) and an input/output interface allowing
completely variable treatment settings. The model was first used to computedose/FW in a water phantom for a 10 cm x FW beam scanned to deliver a "10
x 10 cm2 field", normalized to the dose/5 cm obtained for a same "field" butwith a 10x5 cm beam (FW is the "light-projected" beam width). The measurements, performed with an Exradin A1SL ion chamber, were compared with
TomoPen for a source centred, 0.3 and 1 mm off-axis. Moreover, a simple
dynamic jaws delivery in the "cheese" phantom that includes two cylindricaltargets longitudinally separated by 2.0 cm was simulated. The plan was delivered in two modes: 1) asymmetric jaw opening and fixed couch speed; 2)symmetric jaw opening and variable couch speed. A quality assurance checkof the convolution/superposition (C/S) calculation was previously performedin the assymetric mode with an EDR-2 film according to manufacturer recommendations. This would allow using conservatively C/S as the reference inthis "simple" case to validate TomoPen in a first approach.
Results: For the source centred, the loss of output for small FWs is due tosource occlusion by the jaws. In that case, the agreement between mea-

S 519

surements and TomoPen is excellent (within 1%/1mm). The further drop for
0.3 and 1 mm off-axis sources, more than 30% for the latter and the smallest field (0.2 cm), demonstrate the importance of quality assurance. 0.3 mm
is the tolerance allowed by TomoTherapy. In the dynamic jaws mode, TomoPen simulations were compared to C/S with an excellent agreement within
2%/2mm, as illustrated in the figure embedded in this abstract (asymmetriccase only).

Conclusions: The new version of TomoPen showed its ability to computedynamic jaws-couch tomotherapy treatments. The effect of source displacements on treatment head output was also investigated, demonstrating theneed of source position verification when small fields are used.
1397 poster
RECONSTRUCTION OF THE ACTUAL DOSE PROFILES FROM THE
MEASUREMENT DATA
P. Kazantsev12 , V. Klimanov2
1
N.N.B LOKHIN RUSSIAN C ANCER R ESEARCH C ENTER, Department ofRadiation Oncology, Moscow, Russian Federation
2
N ATIONAL R ESEARCH N UCLEAR U NIVERSITY "MEP H I", Radiation physics,
biophysics and ecology, Moscow, Russian Federation
Purpose: The purpose of this research was to investigate the method ofreconstruction of actual dose profiles from the measurement data with use of
detector kernel inverse Fourier transform.
Materials: In this investigation we used the profiles of Clinac 600CD 6MV
beam measured by 2 ionization chambers (PTW 31010 and Exradin A14SL).
The experimental conditions were simulated by BEAMnrc and EGSnrcMP as
well. As a result of comparison of measurement and simulation data thesource and detectors models were verified. The actual dose profiles wereobtained by modeling of dose distribution from the source in pure water. Detector kernel functions were obtained by the inverse Fourier transform of the
MC data. These functions were used for reconstruction of actual dose profiles
from the measurement data. The actual profiles obtained were successfullycompared with ones measured by the film.
Results: As a result, the detector kernel functions were found and actual
dose profiles were obtained. The comparison of these dose distributions withthe film measurements proved successful, as confirmed by the gamma evaluation with 1%/1mm criteria.
Conclusions: The method of detector kernel functions for reconstruction of
actual dose profiles was found successful, as confirmed by the comparisonof reconstructed profiles with film measurements.
1398 poster
UNDER-DOSAGE OF THE MUCOSAL LAYER: HIGH-RESOLUTION
COMPARISON OF MONTE CARLO RADIATION TRANSPORTCODES
M. Taylor1 , L. Dunn1 , T. Kron2 , R. Franich1
1
2

RMIT U NIVERSITY, Applied Physics, Melbourne, Australia
P ETER M AC C ALLUM C ANCER C ENTRE, East Melbourne, Australia

Purpose: Under-dosing of sub-millimetre layers of the mucosa may be important in terms of recurrence rates following radiotherapy of upper-airway
carcinoma. Treatment planning system algorithms may be of questionableaccuracy in assessing such under-dosage (because of limitations relating todose-grid size and accuracy at interfaces of dissimilar media). Monte Carloalgorithms are the ideal choice for dose calculation in such geometries. In
this work, under-dosage is characterised for various treatment parameters(such as beam energy and size) using EGSnrc and GEANT4, and within thiscontext the two codes are compared in detail.
Materials: Calculations are undertaken in a generic voxelised phantom representation of a larynx. The voxel resolution in the vicinity of the tissue-air
interface is 10 micrometers. Calculations are performed using EGSnrc and
GEANT4 Monte Carlo codes. Calculations were performed on the VPAC
Tango AMD Opteron system, typically using 20 AMD Barcelona 2.3 GHz quad

S 520MC FOR TPS

MC FOR DOSIMETRY AND QA

core processors per simulation. Differences between EGSnrc and GEANT4
are compared quantitatively for the same geometry and beam spectra.
Results: Results show the predicted under-dosage within the mucosal layer(see Figure for example). Under-dosage is more pronounced for higher energies and smaller field sizes. GEANT4 consistently predicts lower doses
within the interfacial regions compared to EGSnrc; however, this difference
decreases with depth, such that by 500 micrometres depth in tissue, the twocodes are within 1 % of each other.

FIGURE CAPTION: Data illustrating under-dosage of mucosal layer (first 2
mm of tissue adjacent to airway plotted in each graph) for various parameters; a parallel-opposed field was employed in each case. (a) Dose in thefirst 2 mm adjacent to the upper airway, calculated using EGSnrc. (b) Ratio of doses calculated with GEANT to those calculated with EGSnrc. (c)EGSnrc doses plotted against corresponding GEANT4 doses (line of identity represents perfect agreement) for different treatment beams. (d) EGSnrc
doses plotted against corresponding GEANT4 doses (line of identity represents perfect agreement) for different field sizes at 6 MV.
Conclusions: The first 10 microns of tissue adjacent to airways may receive
between 3 and 7 % less than the maximum dose (at ~2mm depth in tissue)
for parallel-opposed treatments, depending on the treatment energy and fieldsize. GEANT4 is shown to predict lower doses at interfacial regions than
EGSnrc, with differences of up to 8 % observed (differences being greater for
lower energy treatment beams).

MC for TPS
1399 poster
CHARACTERIZATION OF THE HIGH DEFINITION MLC: A MONTECARLO STUDY
M. K. Fix1 , W. Volken1 , D. Frei1 , D. Frauchiger1 , E. Born1 , P. Manser1 , D.
Terribilini2
1
D IVISION OF M EDICAL R ADIATION P HYSICS, Inselspital - University ofBern, Switzerland, Bern, Switzerland
2
I NSELSPITAL , U NIVERSITÄT B ERN, Bern, Switzerland
Purpose: Recently the High Definition (HD) MLC was commercialized by
Varian Medical Systems providing high resolution in the center section of thetreatment field. The aim of this work is to investigate the characteristics of the
HD-MLC using Monte Carlo (MC) methods.
Materials: Based on the information of the manufacturer, the HD-MLC was
implemented into the already existing Swiss MC Plan (SMCP). The HD-MLC
consists of 2x32 inner leaves with a leaf width of 2.5 mm and 2x28 outerleaves with a leaf width of 5.0 mm. The implementation has been configured
by adjusting the physical density and the air gap between adjacent leaves
in order to match transmission measurements for the 6 and 15 MV photon
beams of a Novalis TX. The transmission measurements have been performed in water using gafchromic films and an ionization chamber at an SSD
of 95 cm and a depth of 5 cm. The implementation was validated by comparing measured and calculated penumbra values (80%-20%) for different fieldsizes and water depths. The validated implementation of the HD-MLC has
been used for its physical characterization. For this purpose, phase space(PS) files have been generated below the fully closed MLC of a 40x22 cm2field size for 6 and 15 MV, respectively. The phase space files have been analyzed in terms of energy spectra, mean energy, fluence and energy fluencein the direction perpendicular to the MLC leaves and have been comparedwith the corresponding data using the well established Varian 80 leaf andMillennium MLCs.
Results: The MC simulation of the configured HD-MLC lead to transmission
values of 1.25% and 1.34% in the central part of the field for the 6 and 15 MV
beam, respectively. The corresponding ionization chamber measurements
result in a transmission of 1.20% and 1.35%. Good agreement has also beenfound for the comparison between transmissions profiles resulting from MC
simulations and film measurements. The simulated and measured values forthe penumbra agreed within <0.5 mm for all field sizes, depths and beamenergies. The energy spectrum and the mean energy are almost identical forthe three MLCs. However, the fluence and energy fluence are significantly
different. Due to the different leaf widths of the MLCs, the shape of these
distributions is different; each representing its leave structure. Due to theincrease in width from the inner to the outer HD-MLC leaves, the fluence andenergy fluence distributions clearly decreases below the outer leaves. The 80
leaf and the Millennium MLC lead to an increase of the fluence and energy
fluence by a factor of about 1.5 and 1.4, respectively, compared with thoseresulted for the HD-MLC.
Conclusions: The HD-MLC has been successfully implemented into the
SMCP. Comparisons between MC calculations and measurements show very
good agreement. The SMCP is now able to calculate accurate dose distributions for treatment plans using the HD-MLC. This work was supported by
Varian Medical Systems.
1400 poster
COMMISSIONING OF A COMMERCIAL TPS BASED ON THE
VMC++ MC CODE FOR ELECTRON BEAMS: VALIDATION AND
COMPARISON WITH EGSNRC
F. Alice12 , A. Martignano1 , S. Franca1
1
2

I.O.V., Medical Physics, Padova, Italy
S CHOOL OF M EDICAL P HSYICS, Padova, Italy

S 521

Purpose: Some commercial TPS already use MC engines for dose calculation. The aim of this work was to perform the commissioning of the VMC++
Monte Carlo (MC) engine implemented in the Oncentra Masterplan TPS forelectron dose calculation, and to verify its accuracy comparing the results tothe EGSnrc MC code.
Materials: The Oncentra Masterplan TPS (Nucletron) uses the VMC++ MCengine for electron beam dose calculation. The LINAC was a Siemens
Primus, with 5 electron energies, ranging from 5 to 12 MeV. The commissioning procedure for the TPS consists of measurements of output factors
and profiles in x,y and z direction, in both air and water: the measures aresent to Nucletron and the returned commissioned data are verified by theuser. The BEAMnrc MC code was used as a benchmark: BEAMnrc required
the geometries of the linac head, which were provided by Siemens; the optimisation was done considering PDD and profiles in water. The output factors(OF) was measured with a Markus Advanced ion chamber, while the profiles
and PDD were measured with diodes. Commissioning results were evaluatedby means of 1D Gamma Analysis (2%, 2mm), calculated with an home-madeMatlab program.Masterplan dose distribution maps were compared to the results of BEAMnrc, in two virtual phantoms: one made of water with an air
insert, and the second with a bone insert. The comparison was done bymeans of 2D Gamma Analysis (3%, 3mm), and comparing significant profiles
and PDD.
Results: The results of the commissioning of the TPS were good: the OFs,the PDDs, and most of the profiles matched well with the measurements;
some mismatch was found with large beams at higher energies (calculated
profiles showed an increase in beam edges that is not present in the measurements) and with lower energies (calculated profiles are slightly narrower
than measurement). The optimisation of the BEAMnrc model of the LINAC
required the modification of some component to match the calculated andmeasured profiles: the final agreement was very good. The agreement of thedose distributions calculated with the TPS and with EGSnrc with the air-insert
phantom was high; with the bone-insert phantom there were differences ofabout 10-15% in the bone region. This is due to the fact that the Masterplan
implementation of VMC++ reports the dose as "dose to water", instead of"dose to medium" (therefore it’s not a dosimetric error).
Conclusions: The result of the commissioning of Oncentra Masterplan wasgood and the optimisation of the BEAMnrc code resulted was very accurate.
The comparison of dose distributions between the two codes showed an excellent agreement, considering that, in order to ensure compatibility with otherdose calculation engines and dose prescriptions, VMC++ reports the dose as"dose to water" instead of "dose to medium", unlike BEAMnrc. The calculation times with VMC++ were shorter than with BEAMnrc, thus permitting
accurate Monte Carlo dose calculation in routine electron beam radiotherapy
planning.
1401 poster
COMMISSIONING OF A MONTE CARLO DOSE CALCULATIONALGORITHM FOR 6 MV AND 15 MV PHOTON BEAMS FROM A 160
MLC SIEMENS ACCELERATOR
D. Zucca Aparicio1 , J. M. Perez Moreno1 , P. Fernandez-Leton1 , J. García
Ruiz-Zorrilla1 , A. Minambres1
1
H OSPITAL U NIVERSITARIO M ADRID S ANCHINARRO - G RUPO H OSPITAL DE
M ADRID, Servicio de Radiofísica y Protección Radiológica, Madrid, Spain
Purpose: This paper summarizes the evaluation of a dose calculation algorithm based on Monte Carlo (MC) for 6 MV and 15 MV photon beams from a
Siemens linear accelerator provided with 160 MLC.
Materials: BrainLAB iPlan RT Dose 4.1.2. planning system has MC calculation algorithm based on the XVMC code. Dose Profiles, Relative Scatter
Factors and Nominal LINAC Output for both water and air measurements
are needed for a set of square and rectangular radiation fields according toBrainLAB Physics Reference Guide.Dose measurementes were performed
with PTW MP3 water tank with diode PTW 60008 and PTW 60012, pinpoint chamber PTW 31014 and semiflex PTW 31010, PTW 30013, and radiochromic film Gafchromic EBT2.Monte Carlo beam modeling was evaluated for each photon energy from the fluence analysis for a 40 cm x 40 cm
diagonal dose profile modified by the flattering filter shape and the on-axis
and off-axis spectra from PDD measures for a field of 10 cm x 10 cm and40 cm x 40 cm and shifted 125 mm off-axis comparing with calculated by
TPS using 3 mm resolution and 0.5% variance as dose to water calculation
MC parameters.Dose measurements with PTW 31010 were performed to becompared versus calculated with 3 mm resolution 1% variance for a set ofon-axis square and rectangular centered fields, asymmetric radiation fields
shifted 125 mm off-axis in each direction, oblique incidence and varying the
SSD and with MLC shaped figures according to Spanish Protocol for Treatment Planning System Quality Control.
Results: Deviations between measured and calculated dose are within recommended tolerances, except irradiations performed in the most difficult conditions (asymmetric diagonal ends of the radiation field where the fluence isaffected by flattering filter and where the high dose gradient involved makes
difficult to ensure an adequate measurement of the absorbed dose)Monte
Carlo statistical behavour was tested performing the same dose calculation
twice with 3 mm resolution and 1% variance finding a standard deviation

S 522MC FOR TPS

MC FOR TPSof the differences between both calculations of 0.8% confirming that reproducibility of the expected dose is object of fluctuations within the statisticalrandomness compatible with the selected calculation variance.
Conclusions: Dose calculations must be performed with a variance lower
or equal than 1% to have deviations from measured dose below than suggested 2% tolerance because it would mean that with k = 2 there would be a
95% probability that the deviation between calculated and measured dose isbelow 2% tolerance referred above.Clinical dose calculation accuracy in theconfluence zone of N beams for a variance of 1% per beam corresponds toa global variance corrected by 1/sqrt (N) for all N beams. However, it should
also be mentioned the substantial increase in time calculation taken to reduce the variance in a half, and the resolution down to 5 mm in the case of
calculating a phase space defined by a radiation field of 40 cm x 40 cm as forthe collimator studied.
1402 poster
DOSE CALCULATION FOR STEREOTACTIC RADIOSURGERYUSING PRE-COMPUTED SHOTS BY MONTE CARLO SIMULATION
S. Y. Kim1 , I. Toma-Dasu1 , B. Y. Yi2 , C. X. Yu2 3
1
S TOCKHOLM U NIVERSITY AND K AROLINSKA I NSTITUTET, Department ofMedical Radiation Physics, Stockholm, Sweden
2
U NIVERSITY OF M ARYLAND S CHOOL OF M EDICINE, Department ofRadiation Oncology, Baltimore, MD, USA
3
X CISION M EDICAL S YSTEMS, Maryland, USA
Purpose: Empirical dose calculation methods are commonly used for stereotactic radiosurgery (SRS). Due to the large number of beams, compromises
have to be made to limit the volume or the resolution. This research is aimed
to develop the effective dose calculation using pre-computed dose distributions with Monte Carlo (MC) simulation.
Materials: 3D dose distributions from all beams (shot) as well as contributions from each beams are computed with MC simulation on a grid covering
all potential positions. The points at which a "shot" can be placed are limited
to a single plane due to rotational symmetry. The pre-calculated dose values
in a phantom (21 cm x 21 cm x 21 cm) consisting of voxels of 1 mm x 1mm x
1 mm. The amount of data needs to be stored and be resident in computer
memory is about 1GB, easily handled with today’s computers. With the precomputed "shots", the dose computation becomes a simple superposition ofdose matrices corresponding to the actual shots placed. During shot placement or plan optimization, the pre-computed 3D dose matrix corresponding
to the point of a shot placement is determined. If necessary, the corresponding shot dose distribution is rotated around the rotational axis to the correct
location. The dose contributions of each individual beam are needed to handle beam blocking/shielding. If one or more beams are blocked or partiallyshielded, a shot has to be modified by subtracting the dose contributions
from these blocked or shielded beams before a shot is superimposed.
Results: Accuracy of the dose calculation will be evaluated for conformity
and uniformity in comparison with GammaPod SRS and Gamma Knife plans.
The effect of statistical uncertainty in MC dose calculation will be evaluatedfor the improvement of calculation time and accuracy.
Conclusions: An effective dose calculation using Monte Carlo (MC) technique is proposed for SRS technique in radiation therapy. Although the
database construction of dose kernel is laborious work, the method of dose
kernel in applying MC technique will allow the fast and accurate 3D dose
calculation by means of matrix superimposition for radiosurgery treatment
planning.
1403 poster

viation) in the flattened portion of the field,o Distance to agreement in penumbra for small fields within 1.2mmo Outside the field calculations within 2% of
measured data (global maximum) Off-axis ratios within 2% of measurements
for a range of geometries Heterogeneities: Monte Carlo calculated results
within 2% of measurements for oblique geometry low density heterogeneity
IMRT plans: Ion chamber measurements within 0.5% at isocentre. Gamma
analysis: >90% pass at 3%/3mm
Conclusions: Our results indicate that agreement between Monaco®Monte
Carlo calculated results and measurements is within acceptable tolerances
to proceed to clinical implementation for IMRT.

DOSIMETRIC COMPARISON OF IRRADIATION ACCURACY DEPENDENT ON CALCULATION OPTIONS OF EMC ALGORITHM
M. Litoborski1 , S. Adamczyk1 , E. Konstanty1 , M. Kruszyna1
1
G REATER P OLAND C ANCER C ENTRE, Department of Medical Physics,
Poznan, Poland
Purpose: The aim of the study was to check the influence of different parameters used by the electron Monte Carlo (eMC) algorithm on dose accuracy
and time of calculation.
Materials: The study employed the eMC algorithm implemented in the Varian Eclipse system. This algorithm uses several options which were divided
into two groups: optimal and high. The differences between groups were in
accuracy and smoothing level: 2% 1% and Medium Strong, respectively. For
both groups, treatment times were calculated for dose of 2Gy and specified
depths in water using a workstation with processor (CPU) Intel Xeon 3.2GHz
Quad Core. The calculations were done for all combinations of 6 applicators (A) (6x6, 10x6, 10x10, 15x15, 20x20, 25x25 cm2 ) and 6 energies (E)(6, 9, 12, 15, 18, 22 MeV) available on the Varian Clinac 2300 C/D accelerator. All calculated dose distributions were checked with ionization chamber(PTW Markus with PTW Unidos) in water phantom (PTW MP3). The study
compared calculation times, treatment times and single point dose measurements.
Results: During the calculation it was observed that only 1 core of CPU isused by the algorithm for one single field. For higher energy and bigger applicator size, the calculation is more time consuming. For the optimal group, thatchanged from 12 seconds for E:6MeV, A:6x6cm2 to 11 minutes and 39 seconds for E:22MeV, A:25x25cm2 . For the high group, the change was moresignificant: 35 seconds to 52 minutes and 22 seconds, respectively for thesame energies and applicators. Comparing the treatment times, it was observed that only for 3 combinations of applicator and energy the time for thehigh group was shorter than that for the optimal group. Otherwise, the time
was the same or longer, even up to 4.9% (12MU for E:6MeV, A:10x6cm2 ).
Dose measurements showed differences between calculated and measured
doses for both groups. In the high group, the differences were not larger than
3%. For the optimal group, the deviations were usually smaller than 4%. For
5 combinations of energies and applicators, there were differences between
4% and 5.5% (E:6MeV, A:25x25cm2 ).
Conclusions: The new calculation algorithms are faster and provide better accuracy than the ones previously used. However, using more powerfulcomputers, the calculation time is still very long if a very high level of dose
distribution accuracy is required. The group with options set to high showed
better dose distribution accuracy at the cost of calculation time and a little bit
longer irradiation time.
1405 poster

1

Purpose:To commission our 6MV Monte Carlo beam model in
Monaco®v2.03 into clinical use for IMRT.
Materials: A structured programme for commissioning was followed, progressing through different levels of complexity, comparing measurements with
Monte Carlo calculated results. Baseline commissioning was carried out forpercent depth doses, output factors and profiles for a range of geometries.
Upon satisfactory completion of baseline comparisons with measured data,
commissioning progressed onto irregular fields and heterogeneities in reference geometries.Finally, absolute dose comparisons between planned andmeasured data were carried out using ion chambers and various detector
arrays for both simple field combinations and complex IMRT plans.
Results: All results fall within acceptable levels of tolerances set and aresummarised as follows: Percentage depth doses within 2% deviation frommeasurements (global maximum)o Build-up data verified against parallel
plate chamber data was found to agree within 2% beyond 5mm depth Output
factors at reference depth and SSD within 1.2% Profiles within 2% (local de-

Purpose: To determine the suitability and limitations of calculating electron
dose distributions using the Macro Monte Carlo (MMC) method as implemented in Eclipse.
Materials: The MMC version 8.9.08 algorithm was commissioned for a Varian Linear Accelerator for electron energies between 9 and 20MeV. The models were verified using an independent set of profiles and depth doses forfields between 2cm and 25cm square, which had been measured in a watertank using an electron diode.Inhomogeneous phantoms, comprising of 5 and10mm thick sections of cork, as well as protrusions representing a nose and acast with an air gap were manufactured from 25cm square sheets of Perspex.
The phantoms were attached to a custom modified end plate such that their
upper surface was at a known depth below the water. This allowed dose profiles to be taken at a range of depths using an electron diode.The phantoms
were CT scanned, and imported into Eclipse. To take into account the waterthat surrounded the phantoms in the above setup, regions of interest werecreated to override the HU outside the phantoms. The MMC algorithm (with arequested certainty about dmax of 1%, a grid resolution of 1.5mm and a low

Footman1 , K. Applegate1 , L. Harrison1
G UY ’ S & S T T HOMAS ’ NHS F OUNDATION T RUST, Department of Medical
Physics and Radiation Safety, London, United Kingdom

level of Gaussian smoothing) was used to predict line profiles corresponding
to the above measurements.
Results: The distance to agreement of measured and calculated doses on
the central axis and at the edge of the field was typically less than 1mm.
Exceptions were for large fields, which were less well modelled around thefield edge. At 20MeV there was a problem with the field edge for all fieldsizes, beyond the 50% depth dose. The largest distances to agreements
were around 5mm.The MMC algorithm underestimates the perturbations todose within a few mm of a sharp change in electron density. Further awayfrom the density change, the doses are predicted typically to within 1mm.

1404 poster

INHOMOGENEITY MEASUREMENTS FOR THE COMMISSIONING
OF THE MACRO MONTE CARLO ELECTRON DOSE CALCULATIONALGORITHM IN ECLIPSE
M. Green1 , H. Mayles1
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics, Bebington, Merseyside, United Kingdom

DOSIMETRIC COMMISSIONING OF A MONTE CARLO MODEL IN
THE ELEKTA MONACO TREATMENT PLANNING SYSTEM
D. Hodgson1 , D. Convery1 , A. Greener1 , S. Misson-Yates1 , C. Thomas1 , M.

S 523

Conclusions: To be consistent with previous radiation therapy experience
MC photon algorithms should report dose to medium for radiotherapy doseprescription, treatment plan evaluation and treatment outcome analysis. For
MC electron dose calculation water with variable density can be used to countfor the effect of heterogeneity to avoid additional dose conversion issues.
1407 poster

Conclusions: The MMC algorithm calculates dose to a water phantom in aclinically satisfactory manner. However, care is required when considering therequired margins, particularly for large fields and at depth.The Macro Monte
Carlo algorithm predicts hot and cold spots due to scatter perturbation effects.
However near to the perturbation the predicted dose gradients are less thanthose measured.
1406 poster
RADIOTHERAPY DOSE PRESCRIPTION BASED ON MONTE CARLOSIMULATIONS SHOULD USE DOSE TO MEDIUM RATHER THANDOSE TO WATER
C. M. C. Ma1 , J. Li1
1
F OX C HASE C ANCER C ENTER, Department of Radiation Oncology,
Philadelphia, USA
Purpose: The Monte Carlo (MC) method enables accurate dose calculation for radiotherapy treatment planning and has been implemented in somecommercial treatment planning systems. Unlike conventional dose calculation algorithms that provide patient dose information in terms of dose to water the MC method calculates the energy deposition in different media andexpresses dose to medium. This paper discusses the differences in dose
calculated using water with different electron densities and that calculated for
different biological media and the clinical issues in reporting dose using doseto water and dose to medium.
Materials: MC dose calculations were performed in layered phantoms consisting of water and bone compact bone slabs irradiated by high-energy
photon (6-18 MV) and electron (6 20 MeV) beams to compare with doses
computed using conventional dose algorithms and those converted using
stopping-power ratios of water to bone. Patient treatment plans with the entire or partial target volumes filling with bone or soft tissues were recalculatedusing MC simulations to investigate the impact of dose conversion from biological media to water.
Results: Our results show that conventional photon dose calculation algorithms compute doses similar to those simulated by MC using water withdifferent electron densities, which are close (< 4%) to doses to media but
significantly different (up to 11%) from doses to water converted from doses
to media following AAPM TG 105 recommendations (see figure for 10 MV
photon depth doses). Conversion from dose to medium to dose to water in
MC calculated dose distributions will introduce additional dose heterogeneityin targets and critical structures consisting of bone and soft tissues, which
could be confused with actual hot spots or cold spots in isodose distributions
and dose volume histograms (DVH).

VERIFICATION AND CLINICAL IMPLEMENTATION OF A COMMERCIAL MONTE CARLO TREATMENT PLANNING SYSTEM FOR
ELECTRON BEAMS
J. Cygler12 , E. Vandervoort2
1
2

C ARLETON U NIVERSITY, Physics Department, Ottawa, Canada
T HE OTTAWA H OSPITAL C ANCER C ENTRE, Ottawa, Canada

Purpose: Several Monte Carlo (MC) based treatment planning systems are
already commercially available for electron beams and more users are implementing them in the clinical setting. In the case of traditional treatment
planning systems, the main purpose of commissioning tests is to evaluate
the dose calculation accuracy for a variety of beam setups and phantom geometries. In the case of MC based treatment planning systems in addition
to the dose calculation accuracy one also needs to define the optimum calculation parameters, such as number of histories, calculation voxel size, etc.,
which will be applied in clinical use of the system. There are also possible
clinical implementation issues, including dose-to-medium vs. dose-to-water
calculation differences.
Materials: The treatment planning system is XiO electron Monte Carlo (XiOeMC), developed and commercialized by CMS Inc. The electron transport in
air is based on a beam model developed by CMS. For the dose calculations
in a phantom, the planning system uses XVMC algorithm (1). The user has
a control over variety of calculation parameters, such as number of histories,
goal Mean Relative Statistical Uncertainty (MRSU), voxel size, dose-to-wateror dose-to-medium with or without heterogeneity corrections. The experimental data were collected for Siemens Primus linear accelerator for beamenergies 6-17 MeV. The beams were defined by standard applicators or by
cerrobend cutouts. The data were collected for a standard SSD=100 cm andfor the extended SSD=115 cm. The measurements in water were done with
a RFA 300 water tank and a highly doped p-type electron diode (both from
IBA), and NACP and Rk ionization chambers. The measurements in heterogeneous phantoms were performed using GafChromic EBT1 film. The films
were scanned with the optical scanner (Epson Perfection V700) and analyzed
using in-house developed software using Matlab and ImageJ.
Results: All calculations were carried out until the goal MRSU reached 1%.
Excellent agreement was found between Monte Carlo and measured dose
profiles in water. Also very good agreement was found for output factors forstandard and extended SSD for open applicators and cerrobend cutouts, withexception for the smaller cutout sizes (<5x5cm2 ) for 17 MeV at extended SSD.
Dose calculations in heterogeneous phantoms agree well with measurementseven for the most complex 3D type heterogeneity provided that appropriate
calculation voxel sizes are used for a given geometry.
Conclusions: XiO eMC calculated dose distributions agree very well withthe experimental ones in both water tank and heterogeneous phantoms, provided that appropriate calculation voxel sizes are used for a given geometry.
Disagreements between calculated and measured output factors for 17 MeV
at SSD=115 cm for cutout field sizes smaller than 5x 5 cm2 require further
investigation and possibly an improvement of beam model.
References. M. Fippel, Fast Monte Carlo dose calculation for photon beams
based on the VMC electron algorithm",Med. Phys. 26, 1466 (1999);
Acknowledgment: The authors would like to acknowledge the excellent
technical support provided by Dr. J C Satterthwaite of Elekta CMS Softwareand Harold Johns Summer Student Ekaterina Tschistiakova for help with data
analysis. The authors have received a research grant from Elekta.

S 524

PATIENT IMMOBILIZATION AND SUPPORT AIDSPATIENT IMMOBILIZATION AND SUPPORT AIDS

Patient care1408 poster
INFORMATION TO PATIENTS WITH HEAD AND NECK CANCER
DURING THE PERIOD OF RADIATION TREATMENT.
H. Egestad1 , S. Hanssen1 , J. H. Tunstad1
1

U NIV. H OSPITAL OF N ORTHERN N ORWAY, Tromsø, Norway

Purpose: The aim of this prospective single institution study is to get more
knowledge of how to adapt communication with patients during the period ofradical first-line radiotherapy
Materials: The study includes 30 patients with newly diagnosed head andneck cancer. The protocol consists of clinical examination, assessment of thepatients‘general condition, a questionnaire (EORTC QLQ with H&N module)
and an interview at 0, 20, 40 and 60 Gy. The validated EORTC questionnaire
was filled in at 0 and 60 Gy. Eight of the patients were depth interviewed. The
protocol was approved by the local ethics committee.
Results: Thirty of 37 patients who were asked for participation gave theirinformed consent and responded. The results show that 40% have been
informed about skincare at 60 Gy. Forty-seven percent are informed about
nutrition, and 23% about food and beverages that should be avoided during
the treatment period. At the end of treatment 37% had a gastrostomy tube.
Of all patients, 87% used analgesic medication at 60Gy. The average weightloss during six weeks was four kilos.
Conclusions: The study shows that there is a great need for more information and supportive measures regarding nutrition and skin care.
1409 poster
TOWARDS A HOSPITAL-BASED BNCT WITH A STANDARD RADIOTHERAPIC LINAC
E. M. Donegani1 , A. Aiani1 , F. Basilico2 , D. Bolognini1 , P. Borasio3 , P.
Cappelletti4 , P. Chiari5 , M. Frigerio6 , S. Gelosa6 , G. Giannini7 , S. Hasan1 ,A. Mattera1 , P. Mauri5 , A. F. Monti6 , A. Ostinelli4 , M. Prest1 , E. Vallazza7 ,A. Zanini8
1
U NIVERSITY OF I NSUBRIA, Physics , Como , Italy2
CNR - I STITUTO T ECNOLOGIE B IOMEDICHE, -, Segrate, Italy
3
O SPEDALE S AN L UIGI, Oncology, Orbassano, Italy
4
O SPEDALE S ANT ’A NNA, Como, Italy
5
U NIVERSITY OF PAVIA, Biology, Pavia, Italy
6
O SPEDALE S ANT ’A NNA, Radiotherapy , Como, Italy
7
U NIVERSITY OF T RIESTE, Trieste, Italy
8
INFN SEZIONE DI TORINO, Torino, Italy
Purpose:Despite outstanding advances both in radiotherapy andchemotherapy over the last decades, there are still many types of cancers
that cannot be cured by conventional therapies. A possible solution for radiochemo resistant tumors, extended or located close to vital organs seems
to be the BNCT (Boron Neutron Capture Therapy), which combines theanatomical treatment principles of radiotherapy and the targeting standardsof chemotherapy. This experimental radiotherapy requires the selective administration of 10 B to the tumor cells and subsequently the irradiation with athermal (E<10 MeV) neutron beam. The high LET particles produced in the10
B(n, α )7 Li capture reaction induce the apoptosis of the malignant cells.
Proposed in the 1930s, BNCT is still in the early stages of development because of the need of a tumor-seeking 10 B-carrier and a thermal neutron beamat least of 508 ncm2 s1 , currently available only at nuclear reactors. The proposed system is developed within the INFN PhoNeS (PhotoNeutron Source)
project and represents a milestone in the pathway towards the performanceof BNCT treatments in a hospital environment.
Materials: The collimators of the Varian Clinac 2100 C/D of the Radiotherapy
Department at the S. Anna Hospital in Como (Italy) are used to photoconvert
18 MV photons into fast neutrons via giant dipole resonance. The MLC is fully
open, whereas the jaws are closed to produce a 0.5.5 cm2 eld. An outer layerof PMMA is used to thermalize the neutrons. Being approximately of 3105
ncm2 s1 , the achieved neutron ux is at the moment not enough for BNCT
treatments, but the system is under development and useful for exploring thefeasibility of a hospital-based BNCT facility.
Results: The neutron ux has been used to provide a 1D scan of the boron
content in biological specimens, using a 500 MU/min dose rate and detecting the α particles emitted in the capture reaction with a microstrip silicondetector. An absolute calibration was performed using several samples withdifferent known amounts of BPA (Boronophenylalanine); the minimum 10 B
detectable amount is 5 ppm. Moreover, blood samples from a human lungaffected by adenocarcinoma (g.), taken during an ex-vivo perfusion with BPA,
were irradiated with the neutron ux to study the 10 B-uptake in the organ.

Conclusions: The proposed system is useful for exploring the feasibility ofa hospital-based BNCT facility and is intended to be optimized for pharmacokinetic studies on 10 B carriers, neutron dosimetry and 2D imaging of 10 B intissues.

Patient immobilization and support aids
1410 poster
A RETROSPECTIVE STUDY COMPARING THE REPRODUCIBILITY
OF THE WINGSTEP BREASTBOARD TO THE CONVENTIONAL
MT-350 BREASTBOARD IN TANGENTIAL BREAST IRRADIATION
C. Jensen1 , I. Fallmyr1 , N. Skottner1
1
Å LESUND H OSPITAL, Ålesund, Norway
Purpose: The reproducibility of patient positioning using the conventional
breastboard is challenging due to the numerous individual settings theseboards offer. The WingSTEP is a facile breastboard from IT-V, where only
the head cushion offers individual settings. The aim of this study was toassess the precision and stability of the two immobilization devices, and determine whether the WingSTEP has as good, or better, precision and stability
as the conventional MT-350 breastboard from MEDTEC. A secondary aim
was to investigate the adequate CTV to PTV margin for both breastboards.
A third aim was that the WingSTEP only costs around 30% of a conventional
breastboard.
Materials: Retrospectively the portal images of 60 patients treated with tangential breast irradiation technique were analysed. 30 patients where immobilized with WingSTEP and 30 with conventional MT-350 breastboard. Doseplans were based on CT scans with a spacing of 2 mm. All patients werecone beam simulated on the treatment machine just prior to the first treatment session. The portal images were evaluated against the reference digitalreconstructed radiographs generated by the dose planning system. Around1500 images were analyzed giving us systematic and random errors for eachpatient and the group.
Results: The preliminary results show that there is no statistical significant
difference between the two immobilization devices. The patients immobilizedwith the WingSTEP have a smaller random error than the conventional breastboard group, but the systematic error is somewhat larger for the WingSTEP
group. There is also less rotation of the patients in the WingSTEP group.
The CTV to PTV margins were 4 mm and 3 mm in the Lat/Vert direction for
WingSTEP and MT-350, respectively, and 2 mm and 4 mm in the long direction for the WingSTEP and MT-350, respectively. Overall there is close to nosystematic error in the two groups, which can be attributed to the cone beamsimulation performed just prior to the first treatment fraction.
Conclusions: The WingSTEP is a facile immobilization breastboard thatshows as good, or better, reproducibility of patient position than our conventional breastboard. The WingSTEP is easy to handle and well regarded
among the radiation technologists. The WingSTEP is now the standard immobilization breastboard in our clinic

S 5251411 poster

1412 poster

CAMERA-BASED INDEPENDENT COUCH HEIGHT VERIFICATIONIN RADIATION ONCOLOGY
M. Kusters1 , R. Louwe1 , L. Biemans-vanKastel1 , H. Nieuwenkamp1 , R.
Zahradnik1 , R. Claessen2 , R. van Seters2 , H. Huizenga1
1
R ADBOUD U NIVERSITY N IJMEGEN M EDICAL C ENTER, Department ofRadiation Oncology, Nijmegen, Netherlands
2
PANASONIC E LECTRIC W ORKS S ALES W ESTERN E UROPE, Best, Netherlands

COUCH INDEXING - ANOTHER STEP TOWARDS SAFER RADIOTHERAPY
M. Smith1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Radiotherapy, Leeds, United Kingdom

Purpose: If off-line correction protocols are used, initial patient set-up during a treatment fraction remains an important issue that requires special attention, irrespective whether EPID and/or CBCT are available to control andverify patient position. Since sagging of the treatment couch is not properly
taken into account by the electronic readout of the treatment machine, thisread-out cannot be used for initial patient positioning using the isocenter-tocouch distance (ITD). Therefore, initial patient positioning to the prescribed
ITD has been carried out using a ruler prior to each treatment fraction in
our institution. However, the ruler method is laborious and logging of data is
not possible. The objective of this study is to replace the ruler based set-upof the couch height with an independent, user-friendly optical camera-based
method.
Materials: A camera-based independent couch height measurement system
was developed in cooperation with Panasonic Electric Works Western Europe. The camera system is placed at the wall of the treatment room. A strip
with a distinctive pattern is mounted at the lateral side of the couch to enabledetection of the couch using the infrared light. The double-speed camera
is connected to an image-checker system containing a Programmable Logic
Controller (PLC) which calculates the couch height and transfers the realtime data to a digital display. Prior to clinical implementation, the patientswere positioned using a ruler and the logged data of the camera system wascompared with the prescribed ITD.
Results: The figure shows a histogram of the observed deviations (n=125) fora period of four weeks on one of the camera systems. The mean observed
difference was -0.4 mm ± 1.1 mm (1SD). The observed differences reflect
uncertainties of the patient setup using a ruler, the alignment of the laser system, lateral skewness of the couch surface, and the accuracy of the camera
based system. Additional measurements showed that the deviations due tothe camera based system including the couch skewness, and the uncertaintyof the laser positioning system were within 1 mm and 0.5 mm, respectively. It
was therefore concluded that the main source of the observed deviations is
the measurement inaccurate positioning of the ruler during patient setup.

Purpose: The research addresses the suggestions by NRAG that ’ A universal system of couch indexing would reduce errors as the patient moves fromone machine to another’ Using this as a basis, we aimed to look not just at
the move between treatment units but the replication of patient position on
the treatment couch throughout a course of treatment. To minimize treatment
incidents, we want to ensure that treatment is verified not only with respect
to volume on fraction 0/1,2 but also daily, with respect to their position on the
couch itself. This study focused specifically on supine pelvis treatments. By
identifying, trialing and implementing indexible equipment it is hoped that not
only is immobilization improved but the chance of incidents caused by humanerror is significantly reduced.
Materials: The trial consisted of two parts. The first was to asses the feasibility of current equipment with respect to indexing. This was a blue knee
block used as a stand alone indexing device. Following this, once identified,a new piece of equipment, the IT-V Prostep was trialed. Data was collected
and subsequently compared.
Results: The results looked at digital lateral and longitudinal couch values at
the isocentre across a course of treatment. They were split into two sections.
A ’range’ of values and also the difference between the ’set*’ and ’actual*’values. Results for both forms of immobilization were compared. Fig 1 shows
the results for the average difference between the set and actual values. *Set
value The value input into verification system following acceptance of images
at isocentre. *Actaul value The digital readout at the isocentre on subsequent
fractions.

Conclusions: The Prostep immobilization device provided us with both asmaller range of couch position and also a smaller average difference between our set and actual values. In particular the improvement in consistencyof the couch long position was noticeable, especially when looking at the average difference between set and actual values. In practice this will allow us
to input couch values into the verification system and apply a 1cm tolerance
to the set up in all three directions of height, lateral and longitudinal values.
1413 poster

Conclusions: The camera-based independent couch height measurement
system has been implemented successfully in 4 treatment rooms, 6 December 2010. The benefits of this system are a more streamlined workflow, inwhich the couch height is directly visible on a display so that the radiation
technologists can directly move the couch to the correct ITD, reduction ofhuman errors during initial patient set-up, and logging of the couch height.
Accuracy of this system is within 1 mm for all used treatment couch positions.
Limited QA of the system and treatment couch is required to guarantee thatthe system works correctly.

EFFECTS OF AIR REMOVAL ON PELVIC ANATOMY RELATED TO
RECTAL TUBE PLACEMENT
S. Sabater1 , E. Jimenez1 , I. Andres1 , R. Berenguer2 , M. V. Carrizo1 ,A. Martos1 , M. Rivera2 , M. Sevillano Capellan1 , A. Nuñez2 , M. Aguayo
Martos1 , V. de la Vara Olivas3 , M. V. Villas1 , M. Arenas Prat4
1
H OSPITAL G ENERAL DE A LBACETE, Department of Radiation Oncology,
Albacete, Spain
2
H OSPITAL G ENERAL DE A LBACETE, Department of Medical Physics,
Albacete, Spain
3
C OMPLEJO H OSPITALARIO A LBACETE (CHUA), Department of Medical
Physics, Albacete, Spain
4
H OSPITAL S ANT J OAN DE R EUS, Department of Radiation Oncology,
Tarragona, Spain
Purpose: Rectal volume has been related to prostate displacement and survival decrease among prostate cancer patients. Rectal volume changes are
related to two components: fences and air poaches. A policy targeted to reduce fences into the rectum has improved the prostate interfraction position.
Interventions related to rectal gas reduction have been less homogenously
satisfactory. Our aim was to evaluate the prostate, bladder and rectal modifications related to rectal gas removal.
Materials: 26 prostate cancer patients underwent a CT simulation scan without and with a rectal tube. CT scan sets without and with rectal tube wereS 526

P ROTON AND ION THERAPY: C LINICALPATIENT IMMOBILIZATION AND SUPPORT AIDS

rigidly registered; and prostate, rectum, and bladder volumes from each study
were manually segmented. Vector centroids (COM) and volumes were calculated and compared. Mean rectal Hounsfied units (HU) and rectal crosssectional area (CSA) were also calculated.
Results: Rectal volume (428.76 cc vs 401,91 cc) and rectal CSA (81.86 cc
vs 76.57 cc) diminished non-significantly after the tube placement). As expected mean rectal HU significantly increased (-63.3 vs -13.4; p=0.0002) after tube placement. Also bladder increased from the first study to the second(1643.71 cc vs 1748.18 cc; p<0.0001). Although prostate volume decreased
with the tube placement, no significant difference was reached (723.02 cc
vs 464.47 cc). Vector modifications were statistically significant for all threepelvic structures analyzed (rectum: 391.72 vs 390.71; bladder: 356.18 vs
355.48; prostate: 367.10 vs 367.28).
Conclusions: Rectal tubes effectively remove rectal gas poaches in view ofthe statistically significant rectal density increase. The non-significant rectal
volume reduction could be consequence of the low number of cases evaluated. More interesting is the non-clinically relevant vector displacement due
to the tube placement, even if result values are statistically significant. Our
results could have failed to obtain a positive result over prostate displacement
like other clinical maneuvers as diet modifications; while more vigorous interventions reported, like enemas, have been proved to be successful in suchway.

and subsequent improved efficiency with the NID and a decrease in necessity of patient re-positioning and subsequent verification re-imaging has been
documented.Minimisation of deformation and residual set up error has beenpreviously reported in institution studies.
Conclusions: This system was devised according to the orthopaedic principles of fixing the joints to immobilise bony structures.The efficacy of a more
extensive immobilisation strategy has been validated by the institution. Whilst
the extensive body cradle, known as the NID, requires a high level of competence and training, this is offset by increased efficiency in treatment set up.
The institution protocol now mandates its manufacture for all head and neck
IMRT patients.

S 527

daily treatment setup. The new system has proved to be quick and simple
to use providing excellent reproducible patient positioning. The board andits components fit together well, look professional and inspires confidence inboth patient and professional users.

1415 poster
PRONE VERSUS SUPINE POSITION IN RADIOTHERAPY (RT) OF
RECTAL CANCER – WHICH IS THE BETTER FOR TREATMENTREPRODUCIBILITY?
K. Sund Solli1 , B. Brattheim2 , R. J. Reidunsdatter2 , G. Frykholm3 , T.
Strickert1
1
S T. O LAVS U NIVERSITY H OSPITAL T RONDHEIM, Trondheim, Norway
2
S ØR -T RØNDELAG U NIVERSITY C OLLEGE , AMMT, Trondheim, Norway
3
S TATENS S TRALEVERN, Osteras, Norway

1414 poster
IMPLEMENTING A NEW IMMOBILISATION DEVICE FOR HEAD AND
NECK IMRT PATIENTS - DESIGN AND FABRICATION.
M. Wada1 , N. Anderson1 , V. Khoo2 1 , M. Handley1 , D. Lim Joon1 , M. Rolfo1
1
AUSTIN H EALTH, Radiation Oncology, Heidelberg West, Melbourne,
Australia
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, London, United
Kingdom
Purpose: Analysis of 3D verification images via CBCT reveals complex distortional movement occurs, despite conventional immobilisation strategies.
This distortion may impact on the reliability of delivered dosimetry to bothtargets and normal structures.The intent was to design a new effective immobilisation device (NID) for all head and neck IMRT patients and subsequently
implement in the clinical setting.
Materials: The NID consisted of a Civco IMRT reinforced head and neckthermoplastic mask with 7 fixation points to a Civco Type S carbon fiber
baseboard with an extended body cradle manufactured from Ecofoam (a rigid
polyurethane pouring two component foam). The NID extends from the superior aspect of the head, supporting the head and neck and continues below
the level of the olecranon processes and encompasses the upper arms andshoulders. The elbows are supported distally as the foam is contoured aroundthe elbow joint and above the shoulder complex. (Figure 1)

Purpose: Radiotherapy is the standard adjuvant treatment for rectal cancer.
However, a standard for patient positioning is still not established. The aim of
this study was therefore to evaluate the impact of patient positioning on the
reproducibility in treatment of rectal cancer.
Materials: 91 consecutive patients with rectal cancer were randomized to betreated in the supine or prone position, respectively. A total dose of 50-54
Gy was given in 25-27 daily fractions of 2 Gy. Reproducibility was definedby deviations between expected and actual position of bony landmarks in thepelvic region. Set-up errors were measured in the three orthogonal directions (lateral, vertical and longitudinal) by electronic portal imaging and theresulting displacement vector was calculated. Imaging and corrections were
performed according to a verification protocol. An average value, representing the set-up error, was calculated for each patient. Descriptive statistics andindependent samples T-test were used for data analyses.
Results: Data from 83 patients were reviewed (40 in prone position and 43
in supine position). There was no significant difference in set-up errors in any
direction between the two treatment positions. Corrections were performed
more frequent in the prone position compared to the supine position, which
may indicate that the prone position is associated with a lower degree of
reproducibility than the supine position.
Conclusions: This study indicates that set-up errors were similar for patientstreated in supine or prone position in rectal cancer.
1416 poster
SARCOMA PATIENT IMMOBILISATION FOR RADIOTHERAPY – A
NOVEL DESIGN
M. Brittain1 , L. Blake1 , S. Doe1 , K. Loadsman1 , M. Seabrook1 , R. Furner1 ,K. Lankester1
1
B RIGHTON AND S USSEX U NIVERSITY H OSPITALS NHS T RUST, Sussex
Cancer Centre, Brighton, United Kingdom

Results: An acceptable body cradle was designed and the several stages
in fabrication documented. The NID has been successfully implemented including the completion of in-house staff training on fabrication and utility. Patient acceptance and compliance has been high. Ease of patient positioning

Purpose: An action group was initiated to design a new method for the immobilisation of sarcoma patients being treated at the Cancer Centre. The
group included a consultant, a physicist, engineers, radiographers and mouldroom/planning technologists. The main objective was to design a new immobilisation system using standard parts that could be set up quickly andeasily utilising as many reusable items as possible so as to save time andresources whilst maintaining a highly reproducible and accurate setup. This
would enable a patient to be assessed, immobilised and CT scanned in asingle hospital visit.
Materials: A base board with threaded holes covering the whole board area
was manufactured by the Medical Physics Department from a polycarbonate
material. Pairs of angled polycarbonate brackets were designed and manufactured to secure commercially available vacuum bags around the sides andunderneath of the limb to be treated away from the treatment area. An adjustable support was also developed to position the foot at any desired angle.
A polycarbonate support bridge raises non-treated limbs away from the treatment area to enable access for treatment. All these components are fixed
to the base board at any desired location with nylon screws. The board has
locators for reproducible fixation to the treatment couch. This provides a fully
adjustable customised set up for each patient (see figure). Once the limb isin position, thermoplastic webbing is heated and moulded over the exposedpart of the limb between the brackets. The moulded webbing is fixed into
location holes on the top of the brackets. Another piece of webbing is usedon the foot support to inhibit any rotational and lifting movement of the ankle.
The webbing is fitted with quick release fixings for attaching to the brackets.
All the parts of the system are reusable except the thermoplastic webbing.
Results: To date 4 patients have undergone radiotherapy using the newboard, all of whom were comfortable with the initial immobilisation and their

Conclusions: By using parts designed and manufactured by the Medical
Physics Department along with established immobilisation products, an innovative new sarcoma immobilisation system has been developed1417 poster
THE IMPACT OF PATIENT POSITIONING AND BREATHING IN THE
DELIVERY OF BREAST CANCER RADIOTHERAPY
A. Tzikas1 , P. Mavroidis1 , S. Hyödynmaa2 , B. C. Ferreira3 , S. Axelsson1 , N.
Papanikolaou4 , B. Lind1
1
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Department ofMedical Radiation Physics, Stockholm, Sweden
2
TAMPERE U NIVERSITY H OSPITAL, Department of Oncology, Pikonlinna,
Finland3
U NIVERSITY OF AVEIRO, I3N Physics Department, Aveiro, Portugal
4
U NIVERSITY OF T EXAS H EALTH S CIENCE C ENTER /C ANCER T HERAPY AND
R ESEARCH C ENTER, Department of Radiological Sciences, San Antonio,
USA
Purpose: Dose delivery uncertainties can significantly modify the dose distribution given to the target and organs at risk (OAR), which potentially leads toa reduction of local tumor control and an increase of side effects. In this study,
the patient setup and breathing uncertainties characterizing three different irradiation techniques are employed to estimate the impact of these factors inbreast cancer radiotherapy.
Materials: Three groups of breast cancer patients (5 resected with negative
nodes (R-), 5 resected with positive nodes (R+) and 5 mastectomized), weretreated with three different irradiation techniques, respectively. Gaussian distributions were used to approximate the positioning uncertainties in the anteroposterior (AP) and the craniocaudal (CC) directions. For each patientthe effectiveness of the dose distribution applied is calculated by the Poissonand relative seriality models based on the dose-response parameters of thetarget and lung. The three radiation techniques are compared by using thecomplication-free tumor control probability, P+ and the biologically effective
uniform dose, BEUD concepts.
Results: For the R- treatment plans, at the clinically prescribed dose levelof the planned dose distribution, the P+ value is 89.4% for a BEUDCTV of
48.9 Gy, the respective total control probability, PB is 89.8%, whereas thecorresponding total complication probability, PI is 0.4%. The difference ofthe delivered dose distribution from the planned gives ∆P+ = -0.8%, ∆PB= 0.1% and ∆PI = 0.8%. If a different scoring threshold had been used forlung (radiation pneumonitis Grade 1-2 instead of Grade 2 or higher) then the
difference of the delivered dose distributions from the planned regarding the
expected response probabilities would change to -5.7% for the P+, 0.1% for
the PB and 5.7% for the PI. For the R+ case, the P+ value is 86.1% fora BEUDCTV of 49.2 Gy, the PB is 90.2%, whereas the PI is 4.1%. The
difference of the delivered dose distribution from the planned gives ∆P+ =4.0%, ∆PB = -0.1% and ∆PI = -4.1%. For radiation pneumonitis Grade 1-2
the difference changes to 33.9% for the P+, -0.1% for the PB and -34.0%
for the PI. For the Mastectomy case, the P+ value is 93.8% for a BEUDCTV
of 51.8 Gy, the PB is 94.8%, whereas the PI is 0.9%. The difference of thedelivered dose distribution from the planned gives ∆P+ = -8.8%, ∆PB = 2.3% and ∆PI = 6.5%. For radiation pneumonitis Grade 1-2 the differencechanges to -33.0% for the P+, -2.3% for the PB and 30.7% for the PI.

Conclusions: A significant deviation between the planned and delivered
dose distributions can be introduced by the combined effects of positioning
uncertainties and breathing. The adjusted treatment plans show larger lungcomplication probabilities than the original plans of the R- and Mastectomy
cases. This means that the true expected complications are often underestimated in clinical practice. The use of radiation pneumonitis of Grade 1-2
seems to be more clinically relevant.

Proton and ion therapy: Clinical1418 poster
MONTE-CARLO SIMULATION FOR PROTON THERAPY MONITORING USING PET
C. Van Ngoc Ty1 , L. De Marzi2 , S. Jan1 , L. Lestand3 , R. Ferrand2 , C.
Comtat1 , R. Trebossen1
1
S ERVICE H OSPITALIER F RÉDÉRIC J OLIOT, Orsay, France
2
C ENTRE DE P ROTONTHÉRAPIE D ’O RSAY, Orsay Cédex, France
3
C LERMONT U NIVERSITÉ , U NIVERSITÉ B LAISE PASCAL , LPC, BP 10448,
F-63000 C LERMONT-F ERRAND, Clermont Ferrand, France
Purpose: Proton beams are used to treat cancers located in sensitive regions. Methods for monitoring both the spatial distribution and the level ofthe delivered dose have been proposed [1]. Proton primary beam induces
nuclear reactions, leading to positron emitter production. Therefore measurements of the positron emitter distribution in patient (mainly 11 C and 15 O) usingS 528

P ROTON AND ION THERAPY: P HYSICSP ROTON AND ION THERAPY: P HYSICS

Positron Emission Tomography (PET) can be used to monitor the irradiation.
Nevertheless, the monitoring using PET requires a simulation of the expected
positron emitter distribution from the irradiation characteristics to comparewith the PET measurements. Simulations are based on Monte Carlo calculations either designed on purpose [2] or based on GEANT4 toolkit [3]. The aimof this work was to set and validate the physical parameters of the simulations
with GEANT4-v9.2.
Materials: Two measurements were obtained for a proton beam delivering 2
Gy at 134.7+/- 1.8 MeV, and a spread-out Bragg-peak (SOBP) of maximum
energy 116 +/- 2.08 MeV to a PMMA cylinder. The irradiated phantom wasthen acquired on the Biograph6 TrueV PET/CT (5.5 mm image spatial resolution) for 40 min, within a delay of 10-12 min. The associated simulationof the positron emitter production was done with GATE - v6p1 [4]. The PET
acquisition was then modelled by convolving the simulated positron emitter
distribution with a Gaussian function of 5.5 mm FWHM.
Results: The production rates for 11 C and 15 O at 110 MeV in PMMA were1.71 and 0.78 per beam particle (%), coherent with ref [5]. Fig.1 shows themeasured activity obtained from the two first minutes of the acquisition alongwith simulated activity - dose profile and planned dose calculated from thetreatment planning system (TPS). Both the simulated and the TPS dose profiles are in good agreement although the beam is only modelled by a Gaussian beam spread.

to calculate the RBE at each cell location, the irradiation geometry most firstbe reproduced and the local radiation field known at each position. After thatthe microscopic biological effect must be calculated in each cell location.
Materials: In this paper we will describe how the irradiation geometry andthe local radiation field can be calculated with the 3 dimensional general purpose Monte Carlo Particle and Heavy Ion transport code System PHITS.
Then how the RBE can be estimated with PHITS coupled to a Microdosimetric Kinetic (MK) Model which estimates the RBE from the absorbed-dose
probability density of lineal energy (y) calculated with a mathematical function
incorporated in PHITS.
Results: PHITS simulations of fragmentation of 200 MeV/u and 400 MeV/u
carbon ions in water, measured by D. Schardt et al. at GSI (Germany), will
be presented. A comparison between calculated RBEs for 10 % surviving
fraction, for carbon ion as a function penetration depth in human salivary
gland (HSG) cells, using PHITS coupled to a MK model will also be shownfor monoenergetic and spread out Bragg Peaks for carbon beams at different
initial energies.
Conclusions: The comparison of the simulated results and experimental
data shows that PHITS can simulate both carbon interactions with water andRBEs with good precision. PHITS can therefore be used for estimating thebiological dose and RBE for charged particle therapy.
1420 poster
COMPROMISE OPTIMUM” CARBON BEAM ENERGY FOR THERAPY
M. A. Chaudhri1
1
U NIVERSITY OF E RLANGEN -N ÜRNBERG, Erlangen, Germany

Fig. 1: Simulated and measured activity profile with simulated and planned
dose for a SOBP of 10.01 cm water equivalent range.
For the SOBP irradiation, the positions at 50% and 20 % of the last activity
maximum in the last fall-off [1] of the simulated positron activity profile are
72.8 and 79 mm respectively, in good adequacy with the measured values
obtained at 72.2 and 80.4 mm respectively. The discrepancy between experimental and simulated position is higher at 20% than at 50% of the last
maximum, this may be due to a greater impact of the blurring effect at thisposition.
Conclusions: Physical parameters of the simulation with GEANT4 v9.2 havebeen set against experimental measurements. The agreement between simulated and experimental profiles through the positron emitter distribution in
uncomplicated phantoms is good. An improved simulation using GATE software is on going to account for the complexity of the beam, the irradiatedmedium and the PET acquisition for patient monitoring, a complete simulation.

Proton and ion therapy: Physics
1419 poster
CALCULATIONS OF RBES USING PHITS COUPLED TO A MICRODOSIMETRIC KINETIC MODEL
L. Sihver1 23 , T. Sato4 , K. Niita5
1
C HALMERS U NIVERSITY OF T ECHNOLOGY, Applied Physics, Göteborg,
Sweden2
T EXAS A&M U NIVERSITY, Nuclear engneering, College Station, USA
3
R OANOKE C OLLEGE, Department of Physics, Salem, USA
4
J APAN ATOMIC E NERGY AGENCY, Tokai-mura, Japan
5
R ESEARCH O RGANIZATION FOR I NFORMATION S CIENCE AND T ECHNOL OGY (RIST), Tokai, Japan
Purpose: A basic parameter in particle and ion beam therapy is the RBE,
which is defined as the ratio of doses of photons and charged particles inducing the same biological effect. The RBE depends on the depth of the particles
in the human body, the charge and energy of the particles, dose level, cell
type, etc. It therefore varies both over the healthy tissue surrounding a tumor
and in the tumor itself. The ability to calculate with precision the RBE along
the path of the primary and secondary particles in the human body is therefore crucial when using proton and ion beams for radiation therapy. To be able

Purpose: When patients are being irradiated with carbon beams a lot ofneutrons are produced in the patients’ tissues. No organ of the patients canbe shielded against these neutrons. All the organs would receive a certain
amount of additional radiation dose depending upon the energy of the carbon
beam and the location of the Bragg Peak with respect to the organs. These
additional neutrons have the potential to induce new secondary cancers andcause other harmful effects. Therefore, if C-ion therapy has to be conducted,
all possible ways to reduce the production of secondary neutrons have to
be undertaken The only possible way to reduce the neutron (produced inpatients) doses is to adjust the C-ion energy in a way to have the adequate
penetration with minimum amount of secondary neutron production. We havetermed this as the "Compromise Optimum energy".
Materials: There is no reliable data on the production of secondary neutrons
from patients under bombardment with C-ions of different energies, especiallyat the production site which is most important from the radiation dose pointof view. Carrying out these measurements at some distance away from thesource of neutron production are going to give erroneous results due to theabsorption and scattering of the secondary neutrons. By making use of theexperimentally measured neutron fluence and energy distributions from different materials constituting tissue, and combining them in the right proportion,
we have estimated the fluence and energies of the secondary neutrons produced by the interaction of C-ions of 100-400 MeV/u energies with patients’tissues. The data is presented in graphical form.
Results: Our results show that, for a physical treatment dose of 20 Gy in
the Brag Peak, the total fluence of secondary nerutrons produced in patientsare 1.6 x 10 9 / cm 2 , 7.3 x 10 8 / cm 2 , 2.5 x 10 8 / cm 2 and 4,1 x 10 7 /cm 2 respectively at carbon-ions energies of 400,. 300, 200 and 100 MeV/ u. The doses to different organs due to these neutrons have also been
estimated for the organs in the immediate neighbor -hood of the Bragg Peak,
while for far lying organs suggestions are made to compute the respective
doses. Our graphical data would help the users of C-ions therapy to selecttheir own "Compromise Optimum energy"
Conclusions: In our opinion the large number of secondary neutrons produced from patients during therapy with carbon ions, and their corresponding
doses to various organs, indicate they could have real potential to cause newprimary cancers and cause other harmful side-effects in patients. However,
we have provided graphical data which would help to minimise this effect andstill make use of any advantage the carbon ions might have in therapy.
1421 poster
DEVELOPMENT OF A 3D ROUTINE FOR THE AUTOMATIC EVALUATION OF IN-BEAM PET DATA FOR THE ION THERAPYS. Helmbrecht1 , A. Santiago1 , J. Skowron2 , W. Enghardt1 , F. Fiedler3
1
O NCO R AY - N ATIONAL C ENTER FOR R ADIATION R ESEARCH IN O NCOL OGY , Medical Radiation Physics, Dresden, Germany
2
IBA D OSIMETRY, Schwarzenbruck, Germany
3
F ORSCHUNGSZENTRUM D RESDEN -R OSSENDORF, Radiation Physics,
Dresden, Germany
Purpose: In-beam Positron Emission Tomography (PET) is a valuable tool
for an in-vivo, in-situ monitoring of the dose deposition in ion therapy.The
activity distribution of β + -emitters, created in nuclear reactions of the projectile ions and the target nuclei is measured. Since the clinical relevant dose
distribution can not be calculated directly from the activity, the verification

process is based on comparing measured to activity distributions with thosepredicted from the treatment plan. Visual comparison is very time consuming
and requires trained observers, so a (semi)automatic evaluation method isdesirable.
Materials: Deviations in dose delivery appear in most cases in a shift of
the ion range. Based upon 81 patient datasets simulations were performed,
thereby range modifications of ±6 mm were applied. So there are threeclasses: without any modification and with range modification of +6 mm inwater and -6 mm, respectively.Trained experts visually evaluated the activitydistributions and guessed whether a dataset was modified and tried to identify
the kind of modification.A one-dimensional algorithm, comparing two activity
profiles along the beam, developed for the comparison of ion ranges was
extended to 3D. The results of 3D range comparison algorithm were analyzed statistically. For 6 patients the measured in beam PET images and theassociated simulations were evaluated automatically, thereof 12 without any
modification, 11 with a positive, 11 with a negative shift.Besides the statistical
approach, a tool was developed that provides an assisted visual evaluation of
in beam PET measurements. It allows to superimpose relevant data like CT,
in-beam PET, dose distribution and the local result of the range comparison
algorithm.
Results: The highest sensitivity and specificity was obtained by the welltrained observers. The one dimensional range comparison algorithm canclassify many images correctly but requires previous knowledge of the position of a range deviation.The sensitivity and specificity of the 3D algorithm
in combination to the subsequent statistical evaluation is lower than the visual method but higher than the one-dimensional algorithm. The software forassisted visual evaluation shows a good agreement between the calculated
range differences and the deviation found by an observer.
Conclusions: Automatic evaluation of in beam PET data seems to be feasible, at least as an assistance for the physicist and the clinician.
1422 poster
IBA PROTON PENCIL BEAM SCANNING : VALIDATION
F. Dessy1 , N. Linthout1 , S. Gillis1 , M. Closset1
1

I ON B EAM A PPLICATIONS (IBA), Louvain la Neuve, Belgium

Purpose: As proton therapy is becoming more and more clinically available
and Pencil Beam Scanning (PBS) is being introduced as the newest treatment delivery technique, the validation of the delivery technique as well as
the validation of a beam model created for PBS was the objective of thiswork.
Materials: The PBS technique is treating the patient’s target volume in multiple iso-energy layers. Each layer is composed of an array of spots withindividual intensities to modulate the fluence within the layer. This resultsin the delivery of energy and intensity modulated proton beams.The delivery technique accuracy was evaluated in 2D with a complex pattern allowing
evaluation of the spot shape, position, in-plane spatial resolution and the fluence accuracy. The delivery technique was evaluated for a subset of possible energies and gantry angles covering the entire range.A beam model has
been created in the XiO 4.61®TPS (Elekta AB, Sweden) to allow accurate
treatment plan calculation for the PBS technique. Calculated dose distributions were measured using the Zebra (IBA dosimetry GmbH, Germany),a MultiLayer Ionization Chamber (MLIC), for 1D-measurements parallel tothe beam axis and the MatriXXEvolution (IBA dosimetry GmbH, Germany) for
2D-measurements perpendicular to the beam axis. The MatriXX evolution
was modified to increase the collection efficiency in case of very high dose
rates (up to 200Gy/sec). Additionally gafchromic EBT2 (ISP, NJ, USA) film
measurements were performed perpendicular to the beam axis to evaluate
the lateral penumbra with a higher resolution than achievable with the MatriXX.From the 2D MatriXX measurements, a 3D dose distribution was reconstructed and compared with the one exported from the TPS. This comparison,using gamma analysis, was done using the OmniPro-I’mRT 1.7 software (IBA
dosimetry GmbH, Germany).
Results: The 1D measurements showed a range accuracy for the different
pristine peaks better than ±0.1g/cm and a pull-back accuracy, for small energy changes better than ±0.05g/cmThe complex pattern delivered with PBS
showed a 2%/2mm agreement for every beam energy in the range of 100230MeV and at every gantry angle compare to the theoretical fluence. It also
indicated an accurate spot delivery and in-plane spatial resolution .The measured 2D dose distributions correspond within a gamma value of 3%/3mmwith the calculated distributions extracted from the TPS.
Conclusions: This study showed that the IBA PBS, combined with the
Xio®TPS, meets the general accepted gamma criteria of 3 % 3mm in a homogenous phantom and is ready for implementation in proton therapy departments.
1423 poster
IMAGING CHARACTERIZATION OF PRIMA PROTON IMAGING
DEVICE
C. Talamonti123 , S. Pallotta123 , M. Bruzzi42 , M. Bucciolini123 , P. Cirrone5 ,C. Civinini2 , G. Cuttone5 , D. lo presti67 , L. Marrazzo8 , N. Randazzo7 , M.

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Scaringella42 , C. Stancampiano67
U NIVERSITY OF F LORENCE, Clinical Physiopathology Department, Firenze,
Italy
2
I STITUTO N AZIONALE DI F ISICA N UCLEARE , INFN SEZIONE DI F IRENZE,
Florence, Italy
3
AOUC C AREGGI, Florence, Italy
4
U NIVERSITY OF F LORENCE, Firenze, Italy
5
INFN L ABORATORI N AZIONALI DEL S UD, Catania, Italy
6
U NIVERSITY OF C ATANIA, Catania, Italy
7
I STITUTO N AZIONALE DI F ISICA N UCLEARE , S EZIONE DI C ATANIA, Catania,
Italy
8
AOU C AREGGI, Firenze, Italy

1

Purpose: Proton computed tomography (pCT) has several potential advantages in medical applications, as it provides both a direct and precise method
for patient positioning using the therapeutic beam and it a technique for an accurate prediction of proton dose distribution. For both these applications therequired accuracy is 1-2 mm. Moreover, a successful integration of pCT with
proton therapy may lead also to the ultimate form of image-guided 3D conformal radiation therapy.The aim of PRIMA project is to develop a prototype ofComputed Tomograph based on the tracking of each single proton traversing
the phantom. In this study we describe the results of a test beam in Catania at laboratori nazionali del Sud.Beside testing the full apparatus, checking
separately each detector and the data acquisition system, data of phantoms
designed to study spatial and contrast resolution have been acquired using a
62 MeV proton beam. Radiography of several phantoms and a nut have beenreconstructed. The obtained results will be discussed in this work.
Materials: As a first step toward pCT, Prima project developed a proton computed radiography (pCR) prototype capable to carry out a single projection.
The pCR apparatus includes a tracker (based on identical tracker modules,
each including a silicon microstrip detector) to measure proton trajectory anda calorimeter (made of four YAG:Ce optically separated crystals) to measureresidual energy. The tracker modules have been extensively tested and calibrated, to optimize their performance, with b particles and 62 MeV protons at
INFN-LNS. YAG:Ce crystals were tested with 62MeV protons at INFN-LNS,
and with 200MeV protons at Loma Linda University Medical Center (LLUMC).
Results: Beside testing the full apparatus, checking separately each detector
and the data acquisition system, data of phantoms designed to study spatial
and contrast resolution have been acquired. Radiography of several phantoms and a nut have been reconstructed. The obtained results are encouraging. A tomography experiment has been performed too, projections from 0◦
to 180◦ of a phantom were acquired. These data will be used to test and set
up reconstruction algorithms for tomography studies.
Conclusions: A beam test of the full pCR prototype was performed last summer. The prototype permits to image phantoms, producing data suitable todevelop and validate reconstruction algorithms. A new test beam is foreseen
next February, results from these experiments will be presented in this contribution. This work is supported by INFN PRIMA project.
1424 poster
IN VIVO DOSIMETRY DURING PROTON TREATMENTS
V. La Rosa1 , K. Pepper1 , A. Gibson1 , G. Royle1 , A. Kacperek2
1
U NIVERSITY C OLLEGE OF L ONDON (UCL), Medical Physics and Biomedical Engineering, London, United Kingdom
2
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Douglas Cyclotron, Bebington,
Merseyside, United Kingdom
Purpose: Introduction: Proton therapy offers high conformality and dose reduction to organs at risk. However, these benefits require improved localization of the target and mapping of the dose distribution. Estimating the dose
distribution is critical and depends on tissues heterogeneities, organ motion
and secondary particle production.
Objective: We aim to develop an in-vivo dose measurement technique for
proton therapy. Real time evaluation of the dose distribution inside the patient
will allow us to protect as much healthy tissue as possible despite uncertainties in the treatment delivery. We propose to use high atomic number seeds
implanted within the patient. Heavy metals generate x-ray fluorescence whenirradiated with high energy protons ( Particle Induced X-ray Emission). We
will measure these fluorescent x-rays outside the patient continuously during
the treatment and then relate the fluorescent intensity to the dose received atthat point in the patient.
Background: We measured x-ray fluorescence over a range of gold nanoparticle concentrations using the SYRMEP beamline at the Elettra synchrotron,
Italy [1]. The signal was linear with nanoparticle concentration down to theminimum detectable limit. We are extending this work by measuring the xray fluorescence from proton irradiation of gold to the dose deposited in thevicinity of the gold mass. Alternative metals to gold will also be considered
Materials: Metal fiducial markers are often implanted in patients before radiotherapy to improve the target localization and reduce patient setup errors. We
simulated emissions from metal seeds in water irradiated by 60 MeV protons
with Geant4 Monte Carlo code. The physics model included proton energy
loss, multiple Coulomb scattering, nuclear reactions, and radioactive decay.
We validated the model by measuring x-ray fluorescence from (a) a gold foil

S 530

QA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUESP ROTON AND ION THERAPY: P HYSICS

in a water bath generated by an x-ray beam, and (b) gold nanoparticles in atissue-equivalent phantom irradiated by a proton beam at the Clatterbridge
Centre for Oncology.
Results: Simulations indicated that the dose to the patient resulting from xray emissions from gold seeds will be negligible. X-ray energies were highenough to penetrate several cm of tissue to enable external monitoring. Simulation of a water phantom (blue box) containing a gold marker (yellow cylinder), with a proton beam. Gamma emissions(green lines) and other secondary particles are tracked

Materials: This presentation will provide an overview of the project with briefhighlights from all work-packages including results of simulations of lasertarget interactions indicating the potential advantages of radiation pressure
acceleration over the standard mode of target-normal sheath accelerationand examples of the levitation and transport of micron scale aluminium targets. However the main content will be the approaches taken to provide highquality dosimetry in this highly challenging environment where instantaneous
dose-rates are of the order of 109 Gys-1 . The development of a methodology to provide reliable dose estimates for cell irradiations from individual
laser shots will be explained in detail. This methodology uses a combinationof a stack of gaf-chromic film and detailed simulations with the Monte Carlocode FLUKA, and experiments performed on the TIRANIS laser at Queens
University Belfast.
Results: Results to-date indicate that with suitable magnetic separation, lowenergy beams with a spectral width of a few MeV can be generated and used
to irradiate cell cultures in mono-layer. Doses of up to approximately 5 Gy
can be delivered to cells in a single laser shot. The largest correction factors
which are necessary to derive the final dose estimates area) a) correction
for the under-response of the selected gaf-chromic film when irradiated with
low-energy protonsb) b) allowance for the thickness of the cell medium which
overlays the cells and provides nutrition during irradiation (variations in thisthickness also provide the largest dosimetry uncertainty in the pilot experiments performed to-date
Conclusions: Technical challenges are being solved so the ultimate aim ofa clinical proton treatment facility based on laser-induced proton emission
remains possible. Dosimetry methods which can cope with the very highdose rates are proving successful.
1426 poster
LET AND DOSE DEPENDENCE OF THE OXYGEN ENHANCEMENTRATIO IN ION BEAM RADIATION THERAPY
T. Wenzl1 , J. Wilkens1
1
K LINIKUM RECHTS DER I SAR , TU M ÜNCHEN, Department of Radiation
Oncology, München, Germany

Conclusions: Preliminary experiments demonstrated measurable x-ray fluorescence is emitted from a solution containing gold, thus potentially allowing
in-vivo dosimetry. We are extending the analysis to correct for the effect ofoverlying tissues to relate dose at the gold marker to fluorescent intensity.
References: [1] K Pepper, et al ’A system for x-ray diffraction imaging of
nanoparticle biomarkers’, IEEE Nuc Sci & Med Im Conf 2010.
1425 poster
LASER-PLASMA ACCELERATION OF PARTICLES FOR PROTON
AND ION-BEAM RADIOTHERAPY: AN UPDATE FROM THE LIBRACONSORTIUM
S. Green1 , M. Borghesi2 , D. Neely3 , P. McKenna4 , Z. Najmudin5 , C.
Palmer5 , I. Sari6 , M. Tolley3 , A. Ward3 , D. Carroll4 , S. Kar7 , D. Doria7 , J.
Green3 , C. Brenner3 , D. Kirby8 , F. Fiorini8 , K. Kirkby9 , M. Merchant9 , C.
Jeynes9 , H. Palmans10 , D. Shipley10 , R. Nutbrown10 , R. Thomas10 , M.
Kraft6 , K. Kakolee11 , R. Prasad11
1
H ALL E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, U NIVERSITYH OSPITAL B IRMINGHAM NHS T RUST, Department of Medical Physics andRadiation Safety, Birmingham, United Kingdom
2
S CHOOL OF P HYSICS AND M ATHEMATICS , Q UEENS U NIVERSITY B ELFAST,
Belfast, United Kingdom
3
RUTHERFORD A PPLETON L ABORATORY, Central Laser Facility, Didcot,
United Kingdom
4
U NIVERSITY OF S TRATHCLYDE, Department of Physics, Glasgow, United
Kingdom
5
I MPERIAL C OLLEGE L ONDON, Physics, London, United Kingdom
6
U NIVERSITY OF S OUTHAMPTON, Electronics And Computer Science,
University of Southampton, United Kingdom
7
Q UEEN ’ S U NIVERSITY B ELFAST, Physics, Belfast , United Kingdom
8
U NIVERSITY OF B IRMINGHAM, Physics and Astronomy, Birmingham,
United Kingdom
9
U NIVERSITY OF S URREY, Ion Beam Centre, Guildford, United Kingdom
10
N ATIONAL P HYSICAL L ABORATORY, Radiation dosimetry, Teddington,
United Kingdom
11
Q UEEN ’ S U NIVERSITY B ELFAST, Mathematics and Physics, Belfast ,United Kingdom
Purpose: The LIBRA Consortium is exploring the generation of intense highenergy beams of protons, ions, and x-rays from the interaction of high power
short-pulse laser beams with solid targets. The team is focussed particularly
on fabrication, manipulation and delivery of suitable targets into the correct
position for laser-ablation, on the development of suitable diagnostics anddosimetry approaches for these beams, radiobiological characterisation of
the emitted particle beams and techniques to minimise and manage the debris produced during target ablation. The consortium is now entering the final
year of its initial 4-year programme.

Purpose: The increased resistance of hypoxic cells to ionizing radiation isbelieved to be the primary reason for treatment failure in tumors with oxygendeficient areas. This oxygen effect can be expressed by the oxygen enhancement ratio (OER), which is defined as the ratio of doses given under hypoxic
and aerobic conditions to produce the same biological effect. The OER depends on the type of ionizing radiation and decreases with increasing linear
energy transfer (LET) which suggests a potential advantage of high-LET radiotherapy with ion beams. The purpose of this work is to develop a simple phenomenological model based on experimental data from the literature,
which enables us to estimate the clinical impact of OER variations dependingon LET, level of hypoxia and applied dose.
Materials: Our calculations use the standard linear-quadratic (LQ) model with
its two parameters alpha and beta. To describe the oxygen effect dependingon the tissue oxygenation status we suggest the Alper-Howard-Flanders dependence of both alpha and the square root of beta on the oxygen partialpressure (pO2). Furthermore, in the clinical relevant LET region we assume
a linear dependence of alpha on LET and suppose beta to be independent of
LET.
Results: The OER decreases with increasing LET with the steepest slope atapprox. 100 keV/µm. However, the strong LET dependence seen in experiments in vitro is much smaller in vivo because of the large difference between
the oxygen partial pressure in cell experiments compared to the clinical situation. This is demonstrated for a common clinical setup with a carbon ion
spread-out Bragg peak (SOBP). Furthermore, according to our calculations
the OER decreases with increasing dose per fraction for low-LET radiation,and increases with dose for high-LET. Though, this behavior depends on thecell line or more specifically on the given alpha/beta ratios under hypoxic andaerobic conditions.
Conclusions: The proposed model is a simple tool to estimate OER values
in both low- and high-LET radiotherapy. To exploit the full potential of the reduced OER with increasing LET, very high LET values are necessary that are
typically not found in carbon ion therapy. The OER in the most distal tenthof the carbon ion SOBP can be reduced up to 40% compared with the OER
for protons. However, for the mean OER in the target volume the clinical advantage of carbon ions might be relatively moderate, with OER values about
1-15% smaller than for protons. The benefit of proton compared to conventional photon radiotherapy is rather marginal (up to 3% reduction in the OER).
Regarding the dose dependence, the oxygen effect in clinical practice is notvery sensitive to the choice of dose per fraction in both low- and high-LET
radiotherapy. Acknowledgement: Supported by DFG Cluster of Excellence:
Munich-Centre for Advanced Photonics.

1427 poster
PROTON RADIOGRAPHY WITH CMOS APS
E. Gelover Reyes1 , F. Jiménez Spang1 , I. Rosenberg2 , G. Royle1
1

U NIVERSITY C OLLEGE L ONDON, Department of Medical Physics andBioengineering , London, United Kingdom
UCLH, Radiotherapy Physics, London, United Kingdom

2

Purpose: Proton Therapy (PT) offers a remarkable geometrical advantage incancer radiation treatment because of the excellent sparing of organs at risk
and superior conformality. Nevertheless uncertainties can arise from organ
motion, density heterogeneities of tissues and energy straggling of the beam.
In the current procedure for planning PT the stopping power of the tissues thatwill be irradiated are estimated using a CT conversion table that could also
lead to errors in the final proton range computation.With the aim of improving
the quality assurance methods of PT this project investigates the feasibility ofdeveloping a proton radiography system that will take into account the effects
of energy loss and scattering which by other means are not very accuratelyinterpreted.
Materials: CMOS Active Pixel Sensors (APS) are the main component of thedevice’s architecture. A thin layer of silicon can perceive the small energy
deposition of the incoming proton (dE/dx) and to produce the charge migration typical of semiconductors. The generated electron-hole pairs will determine the intensity of the signal and the contrast difference among anatomical
structures will be derived from the changes in density. The detector used isan active pixel CMOS sensor that consists of an array of 520 x 520 pixels
with 25um pitch. It has two operating modes. In the digital mode, the analogue to digital conversion is performed inside the pixel by the on-chip ADCs.
The integration of on-chip intelligent functionality allows the user to addressa region of interest down to 6 x 6 pixels.
Results: The Monte Carlo model of the CMOS sensor and the theoreticalstopping power approximation have been used to determine the values ofenergy deposition that the detector should be able to resolve. An experimentusing a beta particle source was performed to test the practical feasibility ofthis requirement and to estimate the energy resolution of the detector. Our
results show that this technology can be used for tracking purposes since wehave been able to isolate single particle hits in the surface of the detector bysampling at high frequency. The MC model has also been used to observe
the effect to Multiple Coulomb scattering and to study the variation of proton
dose vs. depth on the detector’s surface.
Conclusions: The feasibility of using CMOS APS detectors for proton radiography has been analyzed primarily through the assessment of energy
deposition. It was observed that the interaction of charged particles in thesensitive layer of Vanilla can generate sufficient signal to achieve energy discrimination of single particles. This couple with the acquisition frequency of
CMOS APS will allow us to perform proton counting and hence achieve ahigher degree of density resolution.
1428 poster
VERIFICATION OF A PROTON THERAPY FACILITY MONTE CARLOSIMULATION BASED ON THE GAMOS/GEANT4 FRAMEWORK
J. I. Lagares1 , P. Arce2 , J. A. Terrón3 , J. J. Nieto-Camero4 , F. Sansaloni1 ,A. Korf4 , M. T. Romero Expósito5 , L. Núñez6 , R. Rodriguez7 , M. Loubser4 ,F. Sanchez-Doblado83
1
CIEMAT, Medical Applications Unit, Madrid, Spain
2
CIEMAT, Basic Research, Madrid, Spain
3
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiotherapy Department,
Sevilla, Spain
4
I T HEMBA LABS, Medical Radiation Department, Somerset West, South
Africa5
U NIVERSIDAD DE S EVILLA, Fisiología Médica y Biofísica, Seville, Spain
6
H OSPITAL U NIVERSITARIO P UERTA DE H IERRO, Radiophysics, Madrid,
Spain
7
H OSPITAL U NIVERSITARIO P UERTA DE H IERRO, Radiotherapy, Madrid,
Spain
8
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Fisiología Médica yBiofísica, Sevilla, Spain
Purpose: It is well known that Monte Carlo (MC) is the appropriate tool tostudy the radiation transport in complex geometries, and specially to obtain
the absorbed dose distribution inside real patients, where it is not possible
to do measurements. The aim of this work is a first verification of the MC
implementation under GAMOS [1] of a proton therapy facility. GAMOS is a
new framework to make easier MC simulations with Geant4 using text file
inputs instead of C++ programming. It has already implemented a long set
of tools useful in radiotherapy environments, like dose and kerma scorers,
DICOM file reading, phase space writing and reading, several variance reduction techniques for LINACs, a point detector scorer or a very big collectionof histograms.
Materials: A single beam incident on an anthropomorphic phantom(NORMA) was planned and irradiated. The target volume was a cylinder
with 5 cm of diameter and 5 cm long. Proton beam had an initial energy of
201.36 MeV and it was modulated using a passive beam scattering and its

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diameter was set using a brass collimator. The prescription dose was 10 Gy
into the 90 % isoline in the phantom. A Gafchromic EBT2 film was inserted
in the phantom for verification fig.1. It was calibrated to estimate the dose
distribution from a few cGy to 24 Gy. The MC and film dose distributions
were compared using a home-made program based in MATLAB. The simulation includes every geometry element on the beam line together with the
bunker. The version of GAMOS is based on Geant4.9.4.beta01. The Geant4
QGSP_BIC_HP physics list was used.
Results: The comparison of the treatments shows small differences between
experimental results and MC simulations.

Conclusions: GAMOS has been demonstrated to be an easy-to-use software for the simulation of a proton beam line. [1] P. Arce, P. Rato, M. Canadas
and J.I. Lagares, "GAMOS: a GEANT4-based easy and flexible frameworkfor nuclear medicine applications", IEEE NSS/ MIC 2008 Conf. Record pp316268, 2008

QA for IMRT and rotational therapy
techniques
1429 poster
A FAST FOURIER TRANSFORM BASED DOSE CALCULATIONPROGRAM FOR QUALITY ASSURANCE OF VOLUMETRICINTENSITY-MODULATED ARC THERAPY TREATMENT PLANS
M. L. M. Cheung1 , K. Y. Lee1 , M. C. Chau1 , S. K. Chan1 , K. Y. Cheung1
1

P RINCE OF WALES H OSPITAL, Clinical Oncology, Hong Kong, Hong Kong
(SAR) China
Purpose: To develop a reliable and independent computer dose calculation Quality Assurance (QA) program for verification of Volumetric IntensityModulated Arc Therapy (VIMAT) treatment plans generated by a commercial
Treatment Planning System (TPS).
Materials: The dose calculation algorithm of the QA program developed wasbased on pencil beam convolution implemented by Fast Fourier Transform(FFT). A 30cm long solid water cylinder with 20cm diameter was chosen as
the default phantom for dose calculation. The treament plan was mapped tothe phantom with the isocenter placed on the central axis of the phantom.
Volumetric dose distribution was calculated by the TPS and the QA program
respectively. The results were compared in terms of % deviation in dosevalues at a user defined verification point and a gamma index analysis of 3
orthogonal dose planes cutting through the verification point. If the deviation
between the dose values at the verification point calculated by the TPS andthe QA program was greater than 3% or the passing rate of the gamma index
analysis with a threshold of 5% of the maximum dose and passing criterea
of gamma index <1, 3%/3mm was less than 95%, a measurement based
QA should be performed for the treatment plan. 20 VIMAT (Varian RapidArc)
treatment plans generated by the TPS (Varian Eclipse 8.6) were calculatedusing the QA program.
Results: All of the 20 treatment plans passed the QA test. In the comparison of the dose values at the user defined verification point, the discrepancy between the TPS and QA program calculations were within 3% for all of
the treatment plans. In the gamma index analysis of the 3 orthogonal doseplanes,a passing rate of more than 97% of the pixels was achieved by all of
the treatment plans and the average gamma index value was less than 0.4.
The time required for the whole QA process of one treatment plan excluding
the time used for dose calculation by the TPS was within 15 minutes using a
2.8GHz processor.
Conclusions: The VIMAT treatment plan QA program developed is a useful, reliable and efficient volumetric dose QA program for independent verification of VIMAT treatment plans. It can be an alternative to measurement
based treatment plan QA procedure which requires valuable treatment machine time.

S 532QA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUESQA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUES

1430 poster
AN INNOVATIVE APPROACH TO MLC QA USING AMSI-EPID IVIEWIMAGES
P. Crean1 , A. Esmail1 , S. Weston1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Department of Medical Physics and Engineering, Leeds,
United Kingdom
Purpose: Intensity modulated radiation therapy (IMRT) is a treatment modality that is used to deliver a dose prescription to a tumour site while minimising
the exposure to the surrounding healthy tissues. The correct placement ofhigh-gradient dose regions in and near the target volume is dependent on an
accurate positioning of the MLC leaves during the delivery of the IMRT fields.1
In a recent study, Mu et al.2 demonstrated that a systematic leaf positioning
error of 1 mm in IMRT plans can result in dose errors of up to 7.6% and 12.2%
for the target and critical structures, respectively. Errors of this size can havea biologically significant effect on the outcome of the therapy.3For this reason
the MLC must be accurately calibrated and periodically tested.The authors
have developed a quantitative calibration/QC method (software tool written
in Matlab) using amorphous silicon EPID images which measures individualleaf positions relative to the radiation centre point.
Materials: The EPID used was the iViewGT amSi EPID (Elekta Oncology
Systems, Crawley, UK). The MLC’s used in this work is the 40 leaf MLC with
1 cm width leaves (at isocentre) and the Beam Modulator with 0.4 cm width
leaves, both manufactured by Elekta Oncology Systems. IView images are
acquired of 2 square fields with 180◦ opposing collimator angles and 10 IMRT
segments that are swept across the EPID. A Canny edge detection algorithm
and a Hough transform based algorithm are used to localise the radiation
centre of the two rectangular fields with sub pixel accuracy. As the individual
IMRT images are loaded into the GUI, the centre of each leaf pair is foundutilising the leaf leakage on either side. The MLC X1 & X2 positions are thenobtained using the FWHM of the profile taken through the centre of each leaf.
The X1 & X2 positions are displayed in the GUI in a table format and the’stitched’ IMRT segments are also shown along with a contrast adjustment
tool. Any leaves that are overlapping (underdose) or if there are gaps (overdose) can be instantly observed as well as the actual leaf positions relative tothe radiation central axis.
Results: The software was tested on the whole fleet of 12 linear accelerators.
The positions of leaf pair 20 & a number of leaf pairs either side was validated
using film. Discrepancies of up to 0.5 mm between the film and the software
were obtained. The differences are due mainly to errors in reading the validation films (approximately 0.25 mm) and the difference between the reference
positions of the two measurement techniques; the film based method uses
the optical cross-wires and the EPID based system uses the centre of theradiation field.
Conclusions: The results obtained using the a-Si EPIDs show good
agreement with film, while giving better consistency and reproducibility
than film. The accuracy is good enough to use for re-calibration of the leafbank, as well as for routine QC checks. The EPID based measurement
process is much more efficient than the film as every aspect of the process
is automated.
References
1 TA. Simon, D. Kahler, WE. Simon, C. Fox, J. Li, J. Palta, C. Liu, "An MLC
calibration method using a detector array", Med. Phys. 10, 4495-503 (2009)
2 G. Mu, E. Ludlum, and P. Xia, "Impact of MLC leaf position errors on simple
and complex IMRT plans for head and neck cancer," Phys. Med. Biol. 53,
7788 (2008)
3 ICRU, Report No. 24, 1976

1431 poster
COMMISSIONING OF VOLUMETRIC MODULATED ARC THERAPY(VMAT) WITH PTW OCTAVIUS PHANTOM ACCORDING TO THE
AAPM TG119
T. Giandini1 , E. Pignoli1 , V. Mongioj1 , C. Stucchi1 , G. Zonca1
1
F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Medical Physics,
Milan, Italy
Purpose: Commissioning of VMAT technique by following the tests suggested in the AAPM TG119 protocol. The goals and results achieved fromnine American institutions are also reported in the TG119 protocol, in orderto give a benchmark for optimization process and the calculation accuracy.
Materials: The TG119 protocol consisted of a set of increasingly difficult test
cases: cylindrical multitarget (C1), mock prostate (C2), mock head/neck (C3)and c-shape (C4). The protocol provided CT images with contours and instructions about planning, dose goals, and measurements to be performed.
In our study, all measurements suggested in the TG119 protocol were performed by using PTW Octavius phantom with the 2D-ARRAY seven29 (0.125
cm3 ion chambers), and measuring dose distribution in both coronal andsagittal planes. VMAT plans were generated by Eclipse TPS with AAA algorithm implemented and for a Varian DHX linac with a 6 MV photons beam.
For C1, C2 and C3 two arcs were used: a CW rotation from 240◦ to 120◦(collimator angle 45◦ ) and a CCW rotation from 120◦ to 240◦ (collimatorangle 315◦ ); 360◦ arcs were not used to avoid the treatment couch bars,
moved inwardly under the couch. For C4 two 360◦ arcs were needed to satisfy dose goals and constraints used in the optimization, so the couch bars
were kept far to minimize their influence on the dose distribution. Prescribed
dose was 2 Gy for each plan and a 2 mm dose calculation grid was set in
the TPS.The differences between single point dose measurements and theplanned dose points were expressed as a percentage variation of the prescribed dose; mean values (m) and standard deviations (σ ) were calculated
both for high and low dose regions and confidence limits were produced in
the form CL = |mean| + 1.96σ . The agreement for planar measurements wasassessed using the G function with a DA of 3% and a DTA of 3mm; m and σ
were calculated for the percentages of points passing gamma analysis and
CL were produced in the form CL = (100-mean) + 1.96σ .
Results: For point dose measurements the mean over all the test cases was-0.003 ± 0.007 (CL 0.017) for high dose regions and 0.001 ± 0.007 (CL0.015) for low dose regions, to be compared to -0.002 ± 0.022 (CL 0.045)
and 0.003 ± 0.022 (CL 0.047), reported values in the TG119, averaged over
all the American Institutions. Low standard deviations and CLs mean thatthe expected differences between measured and planned doses are small
and corroborate the VMAT planning and delivering systems accuracy. For
planar dose distributions, the average over both coronal and sagittal planes
was (95.7 ± 4.3)% (CL 12.8%) to be compared to (96.3 ± 4.4)% (CL 12.4%)
in the TG119.
Conclusions: Although the TG119 was suggested for IMRT commissioning
and based on film measurements, the results achievable with VMAT and byusing a 2D-array system allowed a good verification of the VMAT commissioning and the algorithm implemented in the TPS.
1432 poster
COMPARISON OF THREE COMMERCIAL PHANTOMS FORQUALITY ASSURANCE (QA) OF VOLUMETRIC MODULATED ARC
THERAPY (VMAT).
E. Pignoli1 , T. Giandini1 , C. Stucchi1 , V. Mongioj1 , G. Zonca1
1

F ONDAZIONE IRCCS I STITUTO N AZIONALE DEI T UMORI, Medical Physics,
Milan, Italy

Purpose: We compared characteristics and performances of three commercial phantoms, especially designed for QA of rotational treatments.
Materials: Three commercial phantoms were considered in the study: i) the
PTW OCTAVIUS phantom with the 2D-ARRAY seven29, characterized by 729
vented equally spaced ionization chambers (size 0.5x0.5x0.5 cm3 ) arranged
in a 27x27 matrix; ii) the SUN NUCLEAR ArcCHECK, characterized by 1386
diodes (active detector area 0.64 mm2 ) arranged in a helical grid and with aspacing of 1 cm; and iii) the Scandidos Delta4 , characterized by 1069 diodes(active detector area 0.78 mm2 ) arranged on two orthogonal boards and a
spacing of 0.5 cm in the central 6x6 cm2 region and at 1 cm elsewhere in the
20x20 cm2 measurement area. A preliminary study was performed about thedetectors response angular dependence, through delivery of static 6 MV photons beams at different gantry angles on the phantoms. Then, different VMAT
plans were simulated for prostate and H&N cancer by using a 6 MV photons
beam of a Varian DHX linac. The treatments were planned by Eclipse TPS
and each plan was generated by using two arcs: one clockwise from 240◦
to 120◦ (collimator angle 45◦ ) and the other counterclockwise from 120◦ to240◦ (collimator angle 315◦ ). Measured and planned doses were comparedby the G function with a DA of 3% and a DTA of 3 mm.
Results: For OCTAVIUS a -5% dose difference between measured andplanned doses for lateral incidence was obtained, whereas up to +13% in
dose difference was estimated for the ArcCHECK diodes laterally interceptedby the beam. Delta4 did not show any angular dependence, even for diodes
laterally intercepted by static fields. In spite of the great angular dependence
observed for the ArcCheck, during rotational beams the detectors readings
are averaged along the arc so the angular dependence is "washed out" anddoes not affect the whole reading. In fact, for all the phantoms the comparison
between measurements and VMAT plans were similar with more than 95% of
points passing the gamma analysis.ArcCHECK, due to its peculiar detectors
configuration, does not have diodes near the isocentre, then no information
could be obtained for the highly modulated dose region around the isocentre.
On the other hand, OCTAVIUS and Delta4 allowed to obtain information in different planes, especially in coronal and sagittal planes for OCTAVIUS, so thedoses in the target region and at the critical structures could be adequately
checked.
Conclusions: All three commercial phantoms seem to be suitable for pretreatment patient-specific QA for VMAT. ArcCHECK and OCTAVIUS systems
require a calibration procedure easier and fast. On the contrary, Delta4 requires a more elaborated and time-consuming calibration to be frequently
repeated. Finally, although the ArcCHECK phantom is a good solution forroutine QA, it is our opinion that it does not give sufficient information for thecommissioning of VMAT.

1433 poster
CRITICAL EVALUATION BETWEEN THE PTW SEVEN29 2D ARRAY™
AND SCANDIDOS DELTA4™ FOR DYNAMIC IMRT AND RAPIDARC™
VERIFICATION
M. Hussein1 , S. Sidhu1 , C. Clark1 , E. Adams1 , T. Jordan1
1
S T L UKE ’ S C ANCER C ENTRE , R OYAL S URREY C OUNTY H OSPITAL,
Guildford, United Kingdom
Purpose: The purpose of this study was to evaluate the PTW seven29 2D
Array™ & Octavius™phantom combination and the ScandiDos Delta4™ for
use in clinical IMRT and RapidArc™verification. The 2D Array™has cubicion chambers with 1cm centre-to-centre spacing whereas the Delta4™ has
cylindrical diodes 0.5cm spacing in the central 6cmx6cm and 1cm elsewhere.
Clinical plan delivery, sensitivity to errors, and ease-of-use were specificallyexamined.
Materials: Dynamic IMRT dose distributions, planned using Varian
Eclipse™v8.9, for prostate, pelvic nodes and head & neck cancer sites havebeen measured, as well as RapidArc™distributions for prostate plans andpelvic nodes plans. The resolution of both systems was tested on a prostate
and a head & neck IMRT plan that had deliberate single MLC positional errorsof 2mm, 5mm, and 10mm throughout the plan introduced by editing the MLC
control files. Measurements were evaluated against the Eclipse planning system dose distribution using the Gamma index (γ ) method of evaluation with a
3% dose difference and 3mm distance-to-agreement criteria. A further evaluation using a 2%/2mm criteria was also carried out.
Results: Both systems compared well in terms of clinical plan evaluation; thetime taken by an experienced user to set-up, deliver 8 clinical IMRT plansand perform on-line evaluation was ~2 hours on both systems. Table 1 compares the ability of each system to detect the intentional errors implemented.
The 5mm and 10mm systematic MLC errors were detected by both systems,
however the 2mm systematic error was difficult to detect. The γ in the region
where the errors occurred was increased in comparison to the surrounding γ
but was still <1 for a 3% dose difference criterion; however in a clinical situation this might be ignored. A 2%/2mm critera made all of the errors detectable
on both systems. Clinically, for the head & neck IMRT plan a 2mm positional
error in the MLC made a maximum local dose difference in the spinal cord of
2.5% and in the prostate plan the rectal dose increased by 0.5%.

Conclusions: The Delta4™ system performed slightly better in terms of detectability of MLC errors. The difference in the systems was more apparent
using 2%/2mm criteria which is related to differences in the physical size ofthe detectors and their spacing. The 2D Array™and Delta4 ™systems were
found to be comparable for clinical IMRT and RapidArc™online verification
and were similar in terms of set-up and batching of plan verification.
1434 poster
DEVELOPMENT OF TECHNIQUES TO VERIFY LONG TREATMENT
PLANS
Y. Lee1 , J. Bedford1 , A. Warrington1
1
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Joint Department of Physics, Sutton, United Kingdom
Purpose: Complicated IMRT delivery methods such as VMAT benefit frompre-treatment verification as numerous small segments may be employed.
Ionisation chamber measurement can be useful but is limited to providing asingle point dose and due to its size, positioning of the chamber is crucial.
Many clinical VMAT treatments are for small volumes and commercial verification equipment has been developed for treatment fields of less than 20cm
in size. The aims of this study are to develop verification techniques for ’long’
treatment volumes such as the craniospinal axis, and to determine the sensitivities of the equipment to delivery error.
Materials: A two-isocentre craniospinal VMAT plan, produced using
SmartArc (Philips Pinnacle v9.0) for a planning target volume of length 48cm,
was used to develop and test the following verification methods:-1) The plan
was recalculated on a Delta4 phantom. The cylindrical PMMA phantom oflength 40 cm had two crossed diode arrays of detection area of 2020cm2 . To
maximise the length of verification, the phantom was irradiated in two opposing positions, covering approximately 40cm of the plan. The pivoting point

S 533

was chosen such to maximise the plan verification as well as to avoid irradiating the electronics. The percentage of measured doses with a Gamma
Index for 4% dose difference and 4mm distance-to-agreement of less than 1
was studied.2) The plan was recalculated on a 16cm wide 30cm high 60cm
long Solid Water phantom. Three Gafchromic EBT films were placed edgeto-edge ’sagittally’ at the centre of the 16cm thick Solid Water and irradiated.
Films were scanned on an Epson Expression 1680 Pro film scanner, preprocessed using in-house software, then analysed and compared to the planned
distribution on Omnipro v6.0. The percentage of the measured area witha Gamma Index for 4% dose difference and 4mm distance-to-agreement ofless than 1 with was studied.To determine the sensitivity of the film and Delta4
to error, changes of ±0.3cm in one isocentre position were introduced andGamma indices recalculated.
Results: 98.8% of the Delta4 diodes and 97.2% of the pixels from the threefilms had a Gamma Index of less than 1, excluding signals less than 20%
of normalised dose. The Delta4 and film Gamma 4%/4mm are shown in the
figure.

Conclusions: The importance of pre-treatment verification with complicatedradiation delivery techniques is even greater for infrequently employed techniques involving large treatment volumes. Both Delta4 and film measurements can be employed simply. Delta4 acquires three-dimensional information and can measure in absolute dose, but is limited by the method used
above, treatment lengths close to 40cm and has a limited spatial resolution.
Gafchromic EBT is advantageous when high spatial resolution is required,
but is difficult to set up, time-consuming to analyse and may not be as reliablein the low dose regions.
1435 poster
DEVELOPMENT OF THE CYLINDRICAL STEPWEDGE FILTER AND
ITS ADAPTATION IN THE CONTROL MEASUREMENTS OF THE
TOMOTHERAPY MACHINE
T. Piotrowski12 , K. Mikolajczyk1
1
G REATER P OLAND C ANCER C ENTRE, Medical Physics, Poznan, Poland
2
U NIVERSITY OF M EDICAL S CIENCES, Electroradiology, Poznan, Poland
Purpose: The tomotherapy machine in its work is unique, due to the rotational movement of radiation source synchronized with couch translation andthe leaves movement of MLC collimator. The basic QA procedures, overlapping with the tests for traditional accelerators, allow in many different ways toverify only the Basic parameters of the device. The aim of this study was tocreate a cylindrical stepwedge filter and the design of appropriate treatment
procedure, taking into account the specific characteristics of the machine,
based on which will be defined the parameters of tomotherapy machine andS 534QA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUESQA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUES

generated beam of radiation. It was also determined the accuracy with whichparameters can be measured using such a construction of the measuringsystem.
Materials: Developed and manufactured a cylindrical phantom (stepwedge filter) consist of four cylinders with a different diameter made ofpolycaprolactam-PA-6 - a material with high mechanical strength, low water
absorption (which ensures the repeatability of measurements) and a density
comparable to the soft tissues of the human body. Designed a appropriate
treatment procedure is performed in dynamic mode, and thus takes into account the specific characteristics of the tomotherapy machine phantom positioned on the couch moves to the inside of rotating gantry. It was performed a
total of 18 treatment procedures under which the parameters were calculated:couch velocity, dose at a depth value, Dose Ratio coefficients, coefficients ofvariation of the dose (so-called Dose Flatness), the time of Gantry Rotation.
11 procedures were performed before and 7 after, the annual general review,which allowed more detailed look at the results, observed changes in the parameters over time and to determine the reference values that can be usedas standards for daily dosimetric measurements.

sent the information to our hospital. Once the model has been set up in
Monaco, dose validation calculations for previous fields were done in a water
phantom. Monaco has two calculation algorithms: pencil beam (used during
the first stage in the optimization procedure) and Monte Carlo. We can validate the treatment planning system by comparing calculated with measured(reference) values. Selected calculation parameters for validation are a grid
spacing of 3 mm and Monte Carlo variance of 0.5 %. The last parameteris the percent dose variance per voxel that we are willing to accept for thesecond stage in the optimization procedure (final dose calculation).
Results: For simplicity, we only present results for square fields, from 2 x 2 to
20 x 20 cm2 (the LINAC will be used only for VMAT treatments, where small
fields are predominant). Measured and calculated output factors are plottedin the figure. The highest difference between measured and calculated values
is 0.88 % for Monte Carlo algorithm and -1.05 % for pencil beam calculation(both for 2 x 2 cm2 square field). With the same calculation parameters, absolute dose values are calculated for the two algorithms. Using Monte Carlo,at 100 cm SSD the difference between measured and calculated values is0.00 %, and at 90 cm SSD is -1.39 %. For pencil beam algorithm, the values
are 0.15 % and -0.17 % respectively.

S 535

1439 poster
ON ROTATIONAL MEASUREMENTS WITH THE ARCCHECK 4D
DIODE ARRAY
M. Skorska1 , A. Ryczkowski1 , T. Piotrowski12
1
G REATER P OLAND C ANCER C ENTRE, Medical Physics, Poznan, Poland
2
U NIVERSITY OF M EDICAL S CIENCES, Electroradiology, Poznan, Poland

where SD and mean were the standard deviation and mean of the measurements respectively. Several patients who had previously undergone
IMRT treatment were replanned using arc therapy techniques, with the delivered/measured fluences compared to the expected values produced by the
Eclipse treatment planning system using a 3%/3mm gamma analysis. The
fluences of the conventional IMRT fields were also measured and comparedto the expected values.
Results: The ArcCheck system was found to be quick to position on thetreatment couch and calibration for absolute dose was straight forward. For
both photon energies, reproducibility of response and response with arc angle
yielded CVs of < 0.3 % and 1.5 % respectively. Response linearity with increasing dose showed a CV of < 0.3%, and dose rate dependence produceda CV of < 0.6 %. Over an 84 minute period the calibration stability had a CVof < 0.2 %.Several clinical arc plans were measured and, using the gamma
evaluation, produced a pixel pass rate > 95 %. Comparison of the conventional IMRT treatment field fluences by the same method also produced apixel pass rate > 95 %.
Conclusions: The ArcCheck dosimetry system demonstrated a responsethat would make this a suitable tool for performing both IMRT and arc therapy
pre-treatment verification, and initial results support the use of establishedgamma analysis tolerances.
1438 poster

Purpose: The purpose of this study was to report initial evaluation of TomoTherapy treatment plan verification using the ArcCheck 4D detector array.
Materials: The ArcCheck (SunNuclear) is a 4D cylindrical detector array, 21
cm in diameter, designed specially for rotational treatment verification measurements. The dosimetry system is based on 1386 diodes arranged in ahelical pattern at 2.9 cm depth with 1 cm spacing. Due to the perpendicular arrangement of the detectors with respect to the beam, they can be used
to measure the entrance and exit photon fluence. 94 TomoTherapy plans
were created in the TomoTherapy Hi-Art treatment planning system (version
3.1.5.3) and verified using ArcCheck. Mostly prostate plans (86%) were considered, although brain (9%), head and neck (4%) and abdomen (1%) cases
were also included in the study. Different treatment planning parameters wereused. Field width varied from 1 cm to 5 cm, pitch factor from 0.107 to 0.43 andplanned modulation factor from 1.5 to 3.5.The ArcCheck phantom was placedin such a way that its geometric center was in the isocenter of the therapeutic machine. A comparison of the planned and measured doses was carriedout using a MapCheck software (SunNuclear) utilizing a gamma evaluation
method.
Results: The comparison between the measured and the planned dose
distribution was performed using a dose difference of 3% and distance-toagreement of 3 mm with a 10% threshold. For these criteria, 86% of the plans
showed that more than 90% of the measuring points had been accepted for
absolute dose analysis. This value was improved to 100% when analysis ina relative dose mode was performed (Fig.1). Among them, 98% of the plans
met the criterion of more than 95%. The average number of points meeting the established criteria was 95.2% (with SD 4.1%) for absolute dose and98.9% (with SD 1.5%) for the relative dose mode.

IMPACT OF DOSE RATE VARIATION IN RAPIDARC PLANNING
L. Cozzi1 , G. Nicolini1 , E. Vanetti de Palma1 , A. Clivio1 , A. Fogliata1
1
IOSI, Medical Physics Unit - RadioOncology Dept, Bellinzona, Switzerland

Results: Analysis of the parameters showed a statistically significant difference in the case of the dose at the depth and coefficient of variation of thedose before and after the review of the machine. This effect was not noticeable In the case of the couch velocity, the coefficients Dose Ratio and the timeof Gantry Rotation. It was determined reference intervals for these parameters, which are as follows: for the couch velocity: ± 1.2%, the average dose
measured at a depth: ± 1.8%, the calculated values of the coefficients Dose
Ratio: ± 0.5% and Dose Flatness (0,53-0,65)%, the time of Gantry Rotation:± 3%. The accuracy of the measured parameters in the case of other tests
are usually referred to within ± 2%.
Conclusions: The results obtained showed that the developed cylindricalstepwedge filter allows a very precisely defined value of these parameters in asingle treatment procedure (lasting 5 minutes). Its use in the daily dosimetricmeasurements can precisely control the work of tomotherapy machine.
1436 poster
DOSIMETRIC VALIDATION OF A COMMERCIAL VMAT PLANNING
SYSTEM: ABSOLUTE DOSE AND OUTPUT FACTORS
F. Clemente Gutierrez1 , J. C. Ramirez Ros1 , M. A. De la Casa de Julian1 ,E. Cabello Murillo1 , M. Martín De Miguel2 , C. Perez Vara3 , M. Prieto
Villacorta3
1
H OSPITAL U NIVERSITARIO D OCE DE O CTUBRE, Radiofísica y ProtecciónRadiológica, Madrid, Spain
2
H OSPITAL C ENTRAL DE LA D EFENSA "G ÓMEZ U LLA ", Oncología Radioterápica, Madrid, Spain
3
H OSPITAL C ENTRAL DE LA D EFENSA "G ÓMEZ U LLA ", Radiofisica, Madrid,
Spain
Purpose: Monte Carlo calculations require a great deal of computing power.
A fast Monte Carlo algorithm was developed for photon beams, making clinical implementation possible. A commercial Monte Carlo based VMAT planning system (Monaco 2.03, CMS / Elekta) is being commissioned in our institution. In this work we validate the dosimetric accuracy of the treatment
planning system comparing absolute dose values and output factors.
Materials: To commission the treatment planning system, relative measurements (depth dose curves and profiles), output factors and absolute dosevalues were measured in a water phantom for several field sizes. In particular, output factors were measured for fields from 2 x 2 to 40 x 40 cm2 , andrectangular fields of 30 x 5 and 5 x 30 cm2 . The absolute dose values required to model the LINAC in Monaco are measured for source-to-surface
distance of 90 and 100 cm and depth of 10 cm (in a 10 x 10 cm2 reference
field). CMS performed the beam modelling with these machine data, andConclusions: Our results show that differences between doses calculated
by Monaco and measured in water phantoms are well within acceptance limits. This conclusion leads us to implement clinically the treatment planningsystem and start VMAT treatments.
1437 poster
EVALUATION OF THE ARCCHECK 4D QA SYSTEM FOR THE
VERIFICATION OF ARC THERAPY TREATMENT
C. Edwards1 , R. Noble1 , J. C. Handley1
1
U NIVERSITY H OSPITAL OF N ORTH S TAFFORDSHIRE, Radiotherapy Physics,
Stoke-on-Trent, United Kingdom
Purpose: Currently, every patient treated with IMRT at the University Hospital of North Staffordshire has the fluence of each field verified using a 2D ion
chamber array. However this system was unable to measure the dose delivered by an arc due to a metal backing plate. Since the department wishedto move to rotational therapy it was necessary to purchase a system capableof measuring dose delivered by an arc. The ArcCheck 4D dosimetry system (Sun Nuclear, Florida) was purchased and it’s suitability for arc therapy
verification was evaluated.
Materials: The ArcCheck system is a cylindrical water equivalent phantom
which has 1386 diode detectors 1 cm apart in a helical arrangement aroundthe central cylinder. The cylinder has a diameter of 26.6 cm and the diodes
are set at a depth of 2.9 cm. A central cavity insert allows measurementof isocentre dose with a traditional detector.The ArcCheck was calibrated inabsolute dose for 6 and 10 MV photons generated by a Varian 2100iX linear accelerator (Varian Medical Systems, California) which uses dynamic leaf
modulation to produce both IMRT and arc therapy treatments. All tests were
performed for both clinical energies. The ArcCheck’s response was tested
for reproducibility and consistency of chamber response with orientation. The
response linearity was investigated across the dose range of 0.1 to 5 Gyand dose rate dependence investigated for varying rates from 100 to 600
MU.min-1 . Stability of calibration with time was also evaluated. A coefficientof variation (CV) for the responses was calculated from

Purpose: An investigation was performed to evaluate the robustness andmutual interplay of two variables concurring to generate modulation patternsof the Varian implementation of Volumetric Modulated Arc Therapy (VMAT),
RapidArc. Dose Rate (DR) and Gantry Speed (GS) are free parameters optimized alongside field aperture shape by the RapidArc engine; however they
are limited by machine constraints, and mutually compensate in order to deliver the proper MU/ during the gantry rotation.
Materials: Four test cases (one geometrical ("CARPET") and three clinical(head and neck, prostate, lymphoma)) were selected and RapidArc plans
were optimized using maximum allowed dose rates from 100 to 600 MU/min.
The maximum gantry speed was fixed to 4.8 /s. The RapidArc Progressive
Resolution Optimization Algorithm (PRO) was used in its 8.6 version; it wasalso known as PRO-II, which was kept without substantial modifications until
version 8.9 included. For all maximum dose rates, the same planning objectives (both in terms of dose-volume constraints and priorities) were used, andin no case any interactive adjustment was performed during the optimization phase. Qualitative analysis of DR and GS patterns from these cases
was summarized together with quantitative assessment of delivery parameters; in particular, all the so-called dynamic log files generated by the Linac
Controllers were analyzed. Pre-treatment quality assurance measurements
and scoring of plan quality aimed to determine whether preferable initial conditions might be identified, or the optimization engine might be invariant tothose variables and capable of providing adequate plans independently fromthe limits applied.
Results: The results summarized in this study, described practically the interplay between two parameters at the basis of the intensity modulation generation in RapidArc: DR and GS variation; in particular,: i) high dynamic
range in MU/◦ is achievable across all dose rates by means of gantry speed
modulation; ii) there is a robust compensation mechanism between the twovariables; iii) from a machine delivery point-of-view, slightly improved accuracy is achieved when lower DR are applied. However, this does not havepractical consequences since measurements and plan evaluation showed alack of clinically relevant deviation; iv) reduced total treatment time is a majoradvantage of high DR.
Conclusions: A trend towards improved plan quality for clinical cases wasobserved with high DR but cannot be generalized, due to the limited amountof cases investigated and the consequent limited significance of the observed
differences . As a minimum benefit, the reduced total treatment time should
be considered as well.

Conclusions: The first experience with the ArcCheck phantom was very positive. However, initial results showed that more precise calibration of the device is necessary. Measurements for other areas should also be performed.
1440 poster
PATIENT-SPECIFIC QA OF IMRT PLANS BY EMPLOYING AN
EPID-BASED DOSE PREDICTION ALGORITHM
E. Moretti1 , A. Schincariol1 , A. Magli2 , M. Duratti1 , M. Crespi1 , C. Foti1 , M.
R. Malisan1
1
U NIVERSITY H OSPITAL AOU SMM, Medical Physics, Udine, Italy
2
U NIVERSITY H OSPITAL AOU SMM, Radiation Oncology, Udine, Italy
Purpose: To test the independent dose prediction algorithm EPIDose by SunNuclear, which performs the calculation of the dose distribution in a phantom
from the fluence image acquired by the EPID for a group of 20 WP (Whole
Pelvis) IMRT plans.
Materials: The EPID employed is a commercially available aSi imaging device Portal Vision aS500 (Varian Medical Systems). WP-IMRT plans were
performed on the TPS MasterPlan (Nucletron).We validated the dose prediction performance by EPIDdose software, comparing the dose distribution
calculated by TPS versus the experimental dose map measured as well by
the portal imager as by a 2D diode-matrix (Mapcheck, SunNuclear), that
represents our routine patient-specific QA device.For both verification procedures, we compared experimental dose maps versus calculated dose maps,by means the gamma index analysis (acceptance criteria: 3%-3 mm, 90%
points). We validated the dose-prediction performance of Epidose comparing
it with Mapcheck one in terms of the following gamma-index distribution parameters: average value, percentage of points that pass the criteria (or withgamma lower than 1), percentage of points having gamma index lower than
1.5 and upper than 2.
Results: The agreement was judged satisfying according to our acceptancecriteria for both methods. EPIDose and MapCHECK performances are statistically correlated but different (in terms of average gamma index and per-

S 536QA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUESQA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUES

centage of passing-points) probably due to different resolution power of thetwo devices.
Conclusions: As part of a wider QA program, in our institute, dose verification of all IMRT plans is performed before treatment of patients for each individual modulated field. Actually, this verification modality is time-consuming.
In order to minimize the workload related to the patient-specific QA in IMRT,
we investigated the role of EPID in the dosimetric verification of the delivery of IMRT plans, by employing the EPIDose dose prediction software. The
empirical model EPIDose showed to represent an adequate and fast tool forverification of IMRT dose distributions.
1441 poster
PLASTIC WATER AS PHANTOM MATERIAL DURING PRETREATMENT VERIFICATION
T. Matzen1 , U. Isacsson2 , J. Medin3
1
S CANDI D OS AB, Medical Physics, Uppsala, Sweden
2
U PPSALA U NIVERSITY H OSPITAL A KADEMISKA S JUKHUSET, Uppsala,Sweden3
S KÅNE U NIVERSITY H OSPITAL AND L UND U NIVERSITY, Lund, Sweden
Purpose: During patient specific pre-treatment verification the patient is substituted with a phantom, the dose to the phantom is calculated in the treatment
planning system and compared with measurements in the said phantom. It
is known that some dose calculation algorithms need extra attention whencalculating the absorbed dose in homogenous phantom materials with nonunit-density. Density scaling artefacts [1], non-appropriate scatter from material with density >1g/cm3 [2,3], absence of phantom material as a separate
entry in the HU-electron density conversion table [4] may contribute to dose
calculation uncertainties during treatment planning. It has been studied if awater-equivalent material can be an alternative option to the widely used andaccepted Polymethyl methacrylate (PMMA) [5].
Materials: Various treatment planning systems were used to calculate theabsorbed dose to the Delta4PT Plastic Water DT [6] phantom; the calculations were performed on different phantom images: True water, MV- and CTscanned Delta4PT PlasticWater phantom. The calculations were comparedwith each other and benchmarked with measurements in Plastic Water DT.
Results:
Dose calculations in water,
MV- and CT-scanned
Delta4PT PlasticWater and dose measurements the phantom in are
identical within 0,5%.
Conclusions:check the beam flatness and symmetry. In order to establish a monthly test
for these parameters, we have used a 2D ion chamber array (MatriXX Evolution, IBA Dosimetry) mounted on a gantry holder with a coupled angle sensor.
With this solution we are able to measure profiles during the gantry arcing(360 in clockwise direction) in parallel (in-plane) and perpendicular (crossplane) to the axis of gantry rotation directions and various dose rates (600,
300, 150, 75 and 37 MU/min).
Results: Beam symmetry and flatness (IEC definitions) are plotted in the
figure for dose rates from 600 MU/min to 75 MU/min. Symmetry is between
101.5 % and 103.0 % at all dose rates in the in-plane direction. Cross-planeis less symmetric as the dose rate is lowered. Flatness is between 100.0 %and 102.5 % in the in-plane direction. Cross-plane flatness get worse with lowdose rate. A maximum value for both symmetry and flatness can be observed
for a gantry angle of around 240 in the cross-plane direction. For 37 MU/mindose rate, symmetry is approximately between 103.0 % and 106.5 % andflatness between 100.5 % and 104.0 % with the same effect (getting worse
as the dose rate is lowered). The beam geometry is satisfactory for all dose
rates.

Conclusions: The beam is stable during the irradiation for dose rates from600 MU/min to 75 MU/min. Beam geometry is also satisfactory for 37 MU/mindose rate, but this lowest value should only be used in small fractions of theoverall treatment.
1443 poster
QUALITY CONTROL OF INTENSITY MODULATED RADIOTHERAPYIN THE FIRST 100 MEN TREATED FOR PROSTATE CANCER:
SEVEN29, POINT DOSE, AND PORTAL IMAGING RESULTS.
A. Kilic1 , C. Cemile1 , N. Kucuk1 , H. AYATA1 , M. Guden1 , K. Engin1
1
A NADOLU S AGLIK M ERKEZI, Department of Radiation Oncology, Gebze /Kocaeli, Turkey

1442 poster
QUALITY ASSURANCE OF BEAM GEOMETRY FOR VMAT TREAMENTS
F. Clemente Gutierrez1 , E. Cabello Murillo1 , J. C. Ramirez Ros1 , M. A.
De la Casa de Julian1 , M. Martín De Miguel2 , C. Perez Vara3 , M. Prieto
Villacorta3
1
H OSPITAL U NIVERSITARIO D OCE DE O CTUBRE, Radiofísica y ProtecciónRadiológica, Madrid, Spain
2
H OSPITAL C ENTRAL DE LA D EFENSA "G ÓMEZ U LLA ", Oncología Radioterápica, Madrid, Spain
3
H OSPITAL C ENTRAL DE LA D EFENSA "G ÓMEZ U LLA ", Radiofisica, Madrid,
Spain
Purpose: Volumetric modulated arc therapy (VMAT) systems deliver radiotherapy treatments with continuous variation of dose rate, MLC leaf positions
and gantry speed. These techniques require new procedures concerning
quality assurance. In this work we present the suggested periodic tests(monthly) to ensure the quality of beam geometry (flatness and symmetry)
for a 6 MV Elekta Synergy with VMAT.
Materials: Special features of VMAT techique implies that beam stability
should be preserved during the irradiation. Periodic tests are necessary to

Purpose: We evaluated quality control in the first 100 men treated with intensity modulated radiotherapy (IMRT) for localized prostate cancer in our
department using seven29, point dose, and portal imaging results.
Materials: Between 2005-2010 over 700 IMRT cases were treated in our department. This study evaluated the first 100 cases of localized prostate IMRT.
Oncor linear accelerator (Siemens Medical Solution, USA) machine at 6 MV
radiotherapy photon energy were used. Using XiO (CMS-USA) treatment
planning system, 77 cases 5, 15 cases 7 and 8 cases 9 area were planned.
Boost to the IMRT, only three patients were treated. Treatment of patientswith median dose 74 Gy (range, 22-76 Gy), the median number of fractions
37(range, 11-38). Patients treatment plans were measured with Seven29
zero degree gantri position before treatment. PTW universal IMRT validation
phantom with central axis point doses were measured for each field. Portal
imaging was done every 3 days. If anatomical differences between portal
imaging and digitally reconstracted radiographs(DRR) from planning system
more than 2 mm then portal imaging was repeated.
Results: Seven29 measurement were evaluated using gamma index method(3% dose difference and 3 mm distance to agreement). Seven29 past point
number of 5, 7 and 9 field number were avarage of 95.0, 94.8 and 92.5 percent respectively. Average IMRT segment number of cases for 5, 7 and 9
number of fields 67, 104 and 156 respectively. Average monitor units (MU)
for 5, 7 and 9 fields were found 618, 707 and 740 respectively. Percentage
point dose differences in the dose of the central axis 5, 7 and 9 fields were1.7, 1.8 and 2.1 respectively. Total average anterior and lateral port number
for one case for 5, 7 and 9 fields were 37.4, 33.9 and 32.3, respectively. A
anterior and a lateral port taken and evaluation time were 8.5 minutes (range
4.8-13.5) before start treatment. Average total treatment time for 5,7 and 9
fields were 9.6(range 6-16), 12.4(range 9-16) and 16.4(range 12-22) respectively.
Conclusions: Seven29 and the point dose measurement differences ofcases are within acceptable levels. Number of points passed in Seven29 withfields number changed between 92.5% and 95%. The point dose percent
differences changed between 1.7 and 2.1.

1444 poster
ROUTINE QUALITY ASSURANCE OF RAPIDARC (ROTATIONALIMRT THERAPY) TREATMENT PLANS
A. esmail1 , H. James2
1
S UFFOLK O NCOLOGY C ENTRE T HE I PSWICH H OSPITAL NHS T, Radiotherapy Physics, Ipswich Suffolk, United Kingdom
2
S UFFOLK O NCOLOGY C ENTRE T HE I PSWICH H OSPITAL NHS T, Ipswich
Suffolk, United Kingdom
Purpose: This study describes our clinical experience of pre-treatment QAof RapidArc treatment plans performed within our centre over the past 12
months. The Varian RapidArc system was commissioned in December 2009.
Pre-treatment dose plane verification ensures dosimetric accuracy of plans
before delivery to the patient. A commercially available arc therapy QA tool,
the Octavius Phantom, along with the Seven29 2D ion chamber array andVerisoft Analysis software (all supplied by PTW) were commissioned andevaluated.
Materials: Initially, the QA of RapidArc treatment plans was carried out by
performing dose point verification in a perspex block using a calibrated pinpoint chamber positioned at a fixed point. An independent check of theplanned Monitor Units (MU) was also performed using Radcalc (Sun Nuclear
Systems) with a tolerance set at ±2%. The perspex block method meant
only one dose point could be measured at a time. The 2D-Array allows forthe evaluation of a possible 729 dose points in a single plane. Two orthogonal planes were acquired in the Octavius Phantom. A model of the treatment
couch, provided in the TPS, was included in the verification. Verisoft software was used to compare the isodose data from the TPS with the measured
data. A Gamma index algorithm, incorporating dose difference and distanceto agreement (DTA), was used for dose evaluation
Results: Initial confidence of the RapidArc system was attained with all Perspex block measurements being within 2% of the expected value obtained
from the TPS (average absolute deviation of 0.74%±1.09%) and all Radcalc
MU checks being within the tolerance of ±2%. For the first 15 RapidArc patients using the Octavius System, the measured dose planes had an average
Gamma Index result of 97.5%±2.4%, using a DTA of 3%/2mm with reference
to Local dose. Only 4 out of the 30 dose planes had a result less than 95%
but all were greater than 90%. Looking at the Gamma maps, areas of failure
were in low-dose regions outside the PTV and delivered dose was lower thanplanned. These plans were deemed clinically acceptable and proceeded totreatment. Verification plan set-up takes 40 minutes per plane, 10 mins isrequired to set the phantom up on the Linac and perform a dose calibration.
Delivery of each arc takes 1-3 mins, and at least 5 mins is required to reorientate the phantom for the next dose plane. Verisoft evaluation of eachdose plane takes no more than 2 mins. Therefore at least 100 minutes total
QA time is required.
Conclusions: The use of the Octavius phantom with the 2D Array andVerisoft software has given us a high level of confidence in the RapidArc
planning and delivery systems. Our tolerance of at least 95% of the evaluated dose points passing the Gamma criteria of 3%/2mm DTA, with reference
to Local dose, is met in the majority of cases. Dose plane measurements in
Octavius is now routine individual pre-treatment patient QA for all our RapidArc plans.

S 537

ball-bearing and the MV field centre.
Results: The displacement of the isocentre calculated from pointer position
data in the vertical, lateral and longitudinal directions (IEC 61217) was foundto be 0.26 ± 0.02 mm, 0.01 ± 0.02 mm, and 0.04 ± 0.02 mm, respectively.
The displacement measured using the ball-bearing phantom was found to be
0.32 ± 0.02 mm, 0.00 ± 0.03 mm, and 0.08 ± 0.06 mm. The effect of the
X-ray tube and XVI panel positions was found to be less than the uncertainty
in the measurements.
Conclusions: The displacement found using the two techniques was similarand small. A correction for the displacement becomes reasonable in stereotactic radiotherapy with small field sizes. An automatic correction requiresthat the XVI system is calibrated with the Apex DMLC attached. Treatment
tables are not designed to control movements in the sub-millimetre range.
Therefore, a correction is not achievable by table movements. A potential
method for correction is to incorporate the displacement in the dose planningsystem.
1446 poster
THE EFFECT OF IONIZATION CHAMBER IN DOSE CALCULATION
AND MEASUREMENT
H. H. Lee12 , K. Son32 , S. H. Shin2 , K. Hee-Joung1 , H. Jung32 , Y. H. Ji32 ,M. S. Kim32 , K. B. Kim32
1
YONSEI U NIVERSITY, Seoul, Korea Republic of
2
KOREA I NSTITUTE OF R ADIOLOGICAL AND M EDICAL S CIENCES, Seoul,
Korea Republic of3
U NIVERSITY OF S CIENCE AND T ECHNOLOGY, Seoul, Korea Republic ofPurpose: It is generalized to use a Computed Tomography (CT) image inradiation therapy planning (RTP). In the image, the existence of the ionizationchamber can cause an image artifact and can effect on a dose computation.
In this study, we evaluate the effect of the ionization chamber in dose calculation and measurement.
Materials: Two phantoms were used in this study. The one was universal
solid water phantom (RW3, ρ = 1.18 g/cm3 , PTW) with ionization chamber(TM31010, 0.125 cc, PTW). Each side of the phantom was length 30 cm andthe total thickness of the phantom was 20 cm. The ionization chamber was
located at 10 cm below the anterior surface. Another one was customized
water phantom as "house phantom (tunnel-shaped phantom)" with ionizationchamber(CC13, IBA, 0.13 cc). The dimension of RW3 was 25 cm x 20 cm x
25 cm. The phantom had a hole on top of it, and we located a bended tube
(J-shaped tube) through the hole. We acquired two images of RW3 phantom
and house phantom with and/or without ionization chamber, respectively. We
used these four images on RT and the planning methods were applied to 2D,
3D, conventional IMRT, and Rapid Arc radiotherapy techniques. These plans
were calculated for prescribed dose; 2 Gy, and then these two phantoms were
irradiated with a 6 MV x-ray from ClinaciX (Varian, USA) and the delivered
dose was measured at the effective point of ionization chamber.

1445 poster
THE DISPLACEMENT OF THE ISOCENTRE OF AN ELEKTA SYNERGY ACCELERATOR CAUSED BY THE APEX ADD-ON DYNAMIC
MULTILEAF COLLIMATOR
S. J. Zimmermann1 , H. L. Riis1 , M. Hjelm-Hansen1
1
R ADIOFYSISK L ABORATORIUM, Odense University Hospital
Purpose: Stereotactic radiotherapy demands small field sizes and smoothly
shaped contours to cover planning target volumes and limit irradiation of normal tissues. The newly developed Apex add-on dynamic multileaf collimator(DMLC) with leaf width of 2.5 mm at isocentre and maximum field size of 142
cm2 may meet this demand. The Apex DMLC is adding a weight of 50 kg to
the radiation head which causes a displacement of the accelerator isocentre.
Two methods for measurement of this displacement are proposed.
Materials: The measurements were carried out on an Elekta Synergy accelerator with an internal multileaf collimator having leaf width of 1.0 cm at
the isocentre. The displacement was measured using a theodolite and apointer attached to the radiation head. The Apex DMLC was simulated byfour weights attached to the radiation head. The centre of mass of the weights
was approximately at the same position as that of the Apex DMLC. The measurements were carried out with and without the Apex weight attached inboth clockwise (CW) and counter-clockwise (CCW) rotation combined withmutual opposed radiation head angles. Pointer positions were measured insteps of 10 over a full gantry rotation of 360. Also, the radiation isocentre
was investigated using a ball-bearing phantom. Images of the ball-bearing
phantom were acquired by a 10 0 cm2 field size for two mutual opposed collimator angles at each of the four cardinal gantry angles. The gantry angles
were reached by CW rotation only. All eight images were analysed using the
Elekta cone beam CT (XVI) software to calculate the average position of theResults: The calculated dose and prescribed dose at the state of with and/or
without ionization chamber were shown in Table 1. The different ratios between the calculated dose and prescribed dose were 0.4% and 0.0%, in thecases of 2D and 3D, respectively. These results are so small that we canignore the effect of ionization chamber. However, the result for the conventional IMRT method was larger than outcomes of 2D and 3D. The different
ratios for the conventional IMRT were 0.9% in RW3 phantom and 6.3% inhouse phantom, respectively. Lastly, the calculated doses for Rapid Arc were
8.9% in RW3 phantom and 9.7% in house phantom, respectively. Dose differences were bigger than 2D and 3D methods. We evaluated the results of

S 538QA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUESQA FOR IMRT AND ROTATIONAL THERAPY TECHNIQUES

3D, conventional IMRT and Rapid Arc in the use of the universal solid water
phantom. As shown in case of without ionization chamber, measured doses
were 1.9 cGy higher in 3D method and 0.7 cGy lower in conventional IMRT
than the prescribed dose of 2 Gy. On the other hand, the difference between
measured dose on Rapid Arc and prescribed dose was 5.2 cGy. This data
was relatively higher than 3D and conventional IMRT results. Then we evaluated the effect for 3D, conventional IMRT and Rapid Arc in the use of thewater phantom. The difference was 4.2 cGy between prescribed dose andmeasured dose on 3D, and in the case of conventional IMRT result was 5.4
cGy lower than prescribed dose, however in case of the Rapid Arc method,dose difference was 0.9 cGy lower than results of 3D and conventional IMRT.

dance with the expectations, the average value of the gamma coefficient in
the area of the high dose is higher than in the low dose. As well as the average gamma value for the DTA = 2 mm is higher than DTA = 3 mm. Analysis
of gamma coefficient calculated for 2 mm of DTA shows that within the areaof high dose, 6% of the plans (3 cases) do not fulfill the acceptance conditions. For 3 mm of DTA 4% of the plans (2 cases) do not fulfill the acceptanceconditions in the same area.100% plans is acceptable within the low dosearea, irrespective of DTA.In the standard plan verification made for rotational
techniques, concerning both PTV and OaR, the following conditions wereadopted: ∆D = 3% and DTA = 2 mm. 2 mm of DTA value increases the accuracy of estimation of possible differences in doses.If the assumed conditions
aren’t fulfilled the given treatment plan is verified twice.
Conclusions: Verification method of treatment plans using the measurmentof ionization chambers matrix is currently used in the Centre of Oncology Gliwice Branch as the main verification method of plans in RapidArc technique.

S 539

portal imaging software. With this method we can measure accurately andwith high spatial resolution dose distributions of IMRT fields in a plane perpendicular to the beam axis, using a simple experimental setup and for any
treatment unit gantry angle.
1449 poster+, A NEW QUANTITATIVE QUALITY ASSURANCE EVALUATIONPARAMETER
S. Stathakis1 , P. Mavroidis2 , C. Shi1 , J. Xu1 , D. Giantsoudi1 , N.
Papanikolaou1
1
T HE U NIVERSITY OF T EXAS H EALTH S CIENCE C ENTER AT S AN A NTONIO,
Department of Radiation Oncology, San Antonio, USA
2
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Department ofMedical Radiation Physics, Stockholm, Sweden

1448 poster
VERIFICATION OF INTENSITY MODULATED FIELDS DOSE DISTRIBUTIONS USING AN EPID
J. M. Perez Moreno1 , P. Fernandez Leton1 , D. Zucca1 , J. García RuizZorrilla1 , A. Minambres1
1
H OSPITAL S ANCHINARRO, Madrid, Spain

Conclusions: In this study, we evaluated the effect of the dose calculationand measurement at the condition of with and/or without ionization chamber.
Though the effect of ionization chamber was relatively small in the 2D, and3D, the condition of with and/or without the ionization chamber in the case of
IMRT, and especially Rapid Arc should be considered for a more accurate andprecise treatment. To more accurate treatment planning and dose verification,
the use of water phantom is recommended rather than the use of universal
solid water phantom. If the use of water phantom is difficult, it is required
to fill the empty space of the universal solid water phantom with equivalentmaterial.
1447 poster
TREATMENT VERIFICATION METHOD FOR RAPIDARC TECHNIQUE
M. Stapor-Fudzinska1 , A. Grzadziel1 , K. Slosarek1
1

C ENTER OF O NCOLOGY - MSC M EMORIAL I NSTITUT, Radiotherapy andBrachytherapy Planning Department, Gliwice, Poland

Purpose: EPIDs are used for patient positioning verification. Their spatial
resolution make them an interesting tool for measuring radiation fields influences with high dose gradients. We have developed a method to convert the
EPID images acquired during the field irradiation in absorbed dose distribution in water at 5 cm depth and SSD 95 cm.
Materials: Two accelerators have been employed with Siemens Oncor
160MLC, equipped with EPID OptiVue 1000S. Detector has an active areaof 40.9x40.9 cm2 and allows to acquire 1024x1024 16 bits images.Imageobtained is an array of values averaged over all subframes readed during acquisition. Acquisition system makes corrections due to the lack of uniformityof response of the photodiode array detector, due of the pixels inactive ordead pixels, and due to the leakage current.Point dose measurements were
performed using chambers PTW 30013, PTW 31010 and PTW 31014. Dose
distribution measurements were carried out with PTW 60008, PTW LA48 andPTW Seven29.Image obtained by an EPID isn’t a dose distribution, becauseradiation behavior in EPID layers components differs from radiation behavior
in water. EPID image is generated after converting megavoltage radiation inlight. This light spreads out over amorphous silicon layer itself which is generated. This is why cannot be established a simple calibration curve dose
image.We have developed a method based on deconvolution of the EPID image obtained by the portal imaging system PSF. The fluence thus obtained
was convolved with a dose deposition kernel to obtain the dose distribution at
5 cm depth and SSD 95 cm . Uniformity corrections and ghosting effects aretaken into account. Signal is converted to absorbed dose using a 10x10 cm2
measurement . MathematicallyPurpose: The accuracy of dose delivery and the clinical impact of eventual
discrepancies have been of great interest the past few years. The aim of thisstudy is to extend the existing Gamma Index by including biological information and propose a new index called the Gamma Plus Index. Furthermore,
to perform a quality control of IMRT treatment plans for lung cancer basedon the concepts of the Gamma Plus Index, biologically effective uniform dose
(BEUD) and complication-free tumor control probability (P+).
Materials: A new quality assurance index called Gamma Plus (γ + ), is proposed based on the theoretical concept of the Gamma Index presented by
Low et al (1998). The biological dose difference (which includes the BEUD)
is used instead of the physical dose difference when performing the γ + calculation. An in-house software was developed to compare the dose distribution
based on the γ + concept. A test pattern for a two-dimensional dose comparison was produced using the developed software platform. The γ + was
also tested on planar dose distributions exported from the Pinnacle Treatment Planning System and film dose distributions acquired in a solid water
phantom for one clinical case. For this analysis a lung cancer case was selected and an IMRT plan was developed for it. The respective planar dose
distributions from the film and the treatment plan were compared based on
the γ + index and evaluated using the radiobiological measures of P+ and
BEUD.
Results: The preliminary results showed that the γ + index showed differences from the Gamma Index for the test pattern analysis since it also considers the biological dose information. For the clinical case, it is observed thatthe γ + index varies for different treatment parameters (e.g. dose per fraction),
which indicates that treatment outcome is considered in the γ + index. In the
figure below the gamma index (upper); gamma plus index with 1.8Gy/fraction(middle); gamma plus index with 2Gy/fraction (lower) are shown for a certain
clinical case. The planar IMRT dose distribution from the film appears to beinferior to the corresponding planar dose distribution from the treatment plan.
The dose area histograms (DAHs) from the plan and film give P+ values of
77.7% and 58.1%, for a BEUD to the target of 63.0Gy.

1. cF: conversion signal-cGy
2. G(trad): ghosting factor
3. Graw(x, y): original image
4. BP(x, y): inverse of uniformity correction
5. kG: EPID PSF

Purpose: The aim is to draw up and put into practice an effektive verification
method of treatment plans in RapidArc technique.
Materials: Treatment plans verification was made for 50 patients, for whom
prostate with an average volume of PTV 136 cm^3 (vol. min. 35,6 cm^3, vol.
max. 375,5 cm^3) was the target volume. For every RapidArc technique withsingle arc and 6 MV photon beam was applied.RapidArc plan verification wasmade (maintaining all the parameters of the original plan: geometry of thetreatment area and radiation time - MU).Dose distribution was measured bymeans of ionization chambers matrix I’mRT MatriXX (Scandidtronix Wellhueffer) located in MultiCube phantom (Scandidtronix Wellhueffer), on line accelerator Clinac 2300 EX (Varian).By means of OmniPro software (Scandidtronix
Wellhueffer) the estimated and measured distribution of dose were compared,
using gamma coefficient known from the literature. Fluention maps were compared for the two assumed conditions: the difference in the dose at point (∆D)
amouting to 3% and the difference of the location of points in the same dose
(DTA) 3 mm and similary 3% and 2 mm. Two regions of interest were taken
into account: the area of a low dose limited by isodose 30% - encompassing
the critical structures and the area of a high dose limited by isodose 80% encompassing the target volume, where average value of gamma coefficient
was estimated. For the gamma coefficient the value of γ≤1 was taken as thetreatment plan acceptance threshold.
Results: The adopted verification method of RapidArc technique used in theCentre of Oncology Gliwice Branch has proved to be successful.In accor-

6. kD: dose deposition kernel 5cm depth
Model accuracy has been verified measuring open fields 5x5, 10x10 and
20x20, 14x10, 10x20, 20x10, 10x6, 6x10, 20x20 wedge cm2 and IMRT fields.
Results: Difference between measured dose with ionization chamber anddetermined from EPID for open fields is -0.3 ± 0.9%. Maximum discrepancy
is 1.5% for 200 dynamic wedge 60◦ .We evaluated percentage of points thatmeet gamma <1 with two criteria: 2% and 3% -2 mm -3 mm. Next tablesummarizes values obtained for 15 clinical treatment fields:

Conclusions: Characterization of the dispersion properties of the EPID canbe done easily through the measurement of several fields. Using the proposed method and the above actions, an analytical model has been developed that allows fast processing of images obtained in DICOM format with

Conclusions: γ + index maintains the original features that are related to theestimation of the dose difference and the spatial shift. Furthermore, the γ +index includes biological information, which can help to more accurately estimate the biological effect difference, which can give a clinical meaning to thequality assurance result. The γ + index combined with the P+ and BEUD concepts show advantageous properties in the quantitative evaluation of dosedelivery and quality control of IMRT treatments because they incorporate information about the expected responses and biological doses of the individualS 540

QA: AUDIT, RISK MANAGEMENT AND LEGAL ISSUES

QA: AUDIT, RISK MANAGEMENT AND LEGAL ISSUES

tissues.

QA: Audit, risk management andlegal issues
1450 poster
ECONOMIC MODEL FOR TOMOTHERAPY PLANNING
G. Guidi1 , A. Bernabei1 , L. Morini1 , G. Gottardi1 , T. Costi1
1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Medical Physics, Modena,
Italy
Purpose: The aim is to evaluate the performance of Tomotherapy plans andverify if it is possible to develop an economic model usable to identify univocally the type of treatment and the cost/benefit applicable to the different
choices, in term of machine parameter, the plan prescription and fractionation
used by the operators.
Materials: We have analyzed 546 plans delivered by the physics department, from June 2008 to November 2010. Four physicists have identified
an own method of planning, based on IMRT experiences and on the multiple choices available by Tomotherapy planning software in term of pitch, field
width, modulation factor and target prescription, patient care plan objectives
and modality of optimization. The treatment plans are been subdivided using
macro categories: 135 Fractionated, 195 Hypo-fractionated (SIB), 72 HypoFractionated, 62 Stereotactic treatments (Head & Body), 38 Radiosurgery, 19
Hyper-Fractionated, 20 Fractionated for Long Volume, 1 Adaptive RT and 4
Emergency. We have recorded all the data available from the planning report
and the treatment time estimation, the number of sinograms and the couchtravel that are used to identify the time consuming of the machine due to plansparameters. The model takes in account the type of plans and objectives, theprescriptions, the number of fraction, the SIB prescriptions (it could reduce
the treatment time cycle) and it tries to fit the plans performances.
Results: It is been developed an economic model to compare the parameters
used by the operators and the cost in term of beam-on time and tumours
extension ratio. The ratio of the models obtained has an agreement with
SRMSD=0,22.The Tomo Plan Model (GTPM) equation is:1451 poster
EILS: A MULTI-INSTITUTIONAL DATABASE FOR INCIDENT LEARNING, BENCHMARKING AND QUALITY IMPROVEMENT
P. Dunscombe1 , M. Gackle2 , J. Ploquin3 , B. Clark4
1
TOM B AKER C ANCER C ENTRE, Department of Medical Physics, Calgary,Alberta, Canada
2
TOM B AKER C ANCER C ENTRE, Radiation Treatment Program, Calgary,Alberta, Canada
3
T HE OTTAWA H OSPITAL, Radiation Safety and Health Physics, Ottawa,
Canada4
T HE OTTAWA H OSPITAL C ANCER C ENTRE, Department of Medical Physics,
Ottawa, Canada
Purpose: Learning from actual and potential (near miss) incidents in radiotherapy is an effective approach to enhancing patient safety and quality ofcare. Our objective was to develop a multi-institutional system to facilitate thereporting of incidents, permit benchmarking against multi-institutional experience, maximise learning opportunities and track quality/safety improvements.
Materials:
The multi-user electronic database is based ontheIncident
Learning
System(ILS)
developedin
Calgary(www.ihe.ca/publications/library/archived/a-reference-guide-for-learning3
from-incidents-in-radiation-treatment ). The original paper-based ILS has
been in use in the Ottawa and Calgary cancer centres for the past four years
with over 3,600 incidents reported so far. To facilitate data entry, analysis
and benchmarking, the ILS has been migrated to an electronic multi-userformat with funding from the Canadian Nuclear Safety Commission. The
format is a proprietary spreadsheet known as Skysheet™allowing secure
multi-institutional access. The incident Reporter selects from predefined
options for six key descriptors of the incident before adding a short free text
description. Once the incident has been reported, an Investigator(s) confirms
the information submitted by the Reporter, assigns basic cause(s) and tags
and documents other activities required by the ILS to complete the incident
file.
Results: An incident may be entered into eILS in approximately 1 minute,see figure. Details of the investigation are entered subsequently. Entry isfast, rarely requiring more than a few minutes. Summary data of all incidents
entered may be reviewed in a list format or as a pie chart or bar graph. A
key feature of the eILS is the ability to filter the incidents prior to display as alist or chart according to one or more of the reported data fields and by basic
cause or tags. Visual comparison may be made between local data and thatentered by other participating institutions.

where TxT= Treatment Time Estimated, MU= Monitor Unit delivered, Dptv1=
the highest dose prescribed to the tumour, Dptv2= the lowest dose prescribed to the tumour in case of SIB techniques, TE= Tumour Extension or
Couch Travel, , S=n◦ of sinograms, MF=Modulation Factor, FW= Field Width,
P=Pitch, GrotP=Gantry Rotation Period.The model is been fitted with the
Beam-On Time Tumours Extension Ratio (BonTER) using the formula:Conclusions: The model could predict or verify the quality of the plan delivered by the physicists and it could be an instrument to evaluate two competitive plans by the doctor in term of cost/benefit and machine usage. Anyway,
it is complicate to declare that some plan parameters of one operator are
better than others. We have developed a model to try to have an objectives
data that it can confirm the best choice applicable. The formula is currently
under developing. The usability of the model for regional and hospital administration and for charge and evaluation of the center performance must
be discussed in deep, because at the moment the model it is based only on
our data. The next develop of the model could focus on the pathologies andit could include other economic parameters such the room time, the time of
setup and delivery, the IGRT comparison time and modality, the operatorsand maintenance cost perhaps using HTA (health technology Assessment)
and/or Markov Model.

Conclusions: A multi-institutional database has been developed for incident
learning. The system is secure, fast and easy to use and presents summary
analyses of the information in the database in user selected formats whichfacilitate multi-institutional learning, benchmarking, trending and quality improvement.
1452 poster
INITIAL DATA PREPARATION FOR DESIGN, CONSTRUCTION ANDTECHNICAL MODERNIZATION OF RADIOTHERAPY CENTERS IN
RUSSIA
D. Kostylev1
1

I NSTITUTE OF M EDICAL P HYSICS AND E NGINEERING, Department ofMedical Physics, Moscow, Russian Federation
Purpose: It’s essential to elaborate special initial data for design, construction
and technical modernization of radiotherapy centers (RTC) without which we
can’t begin our work.
Materials: To start the design of radiotherapy center it’s necessary to havethe following initial data: list of diseases and cancer types to be treated in

3 http://www.ihe.ca/publications/library/archived/a-referenceguide-for-learning-from-incidents-in-radiation-treatment

the RTC list of technologies used in treatment, diagnostic support, pretreatment procedures, physical modification, medical physics service, quality assurance provision and patient and personnel protection planned (daily andannual) patient flow for every cancer type and nosological form regional features (territory size, population, climate, seismicity etc.) which should betaken into account RTC mission and facilities for treatment, research and education RTC structure (departments) and internal functional relations external functional relations list of basic equipment with specifications list of total
equipment with specifications delivery, transport and installation conditions,
technical characteristics, sizes, requirements for power supply, water supply,
ventilation and other equipment information necessary for design layout requirements for the equipment installation and its efficient exploitation patientand personnel protection requirements, shielding requirements, radiation risk
minimization medical physics service and maintenance requirements staffing
requirements and justification comfortable working conditions requirements
for the personnel and its placement preliminary cost estimating of RTC andconstruction stagesMuch attention should be paid to the realization of medical technology management. When purchasing equipment it’s necessary to
implement strategic technology planning, technology assessment and technical audit, to develop equipment and technology management system, to train
personnel and users.
Results: The Russian experience has shown that if the scientific approachis used in RTC design, construction and modernization, the financial losses
don’t exceed 10%-12% otherwise the losses are 87%-90%.
Conclusions: The explicit initial data preparation and specific justification forthe choice and purchase of the RTC equipment must be done in special documents "Medical Technical Requirements" (MTR) and "Medical Performance
Specification" (MPS) which should be worked out by competent and independent specialists from research institutes or professional non-profit organizations. The vendors shouldn’t be involved in this process.
1453 poster
RADIATION ONCOLOGY MODERNIZATION IN RUSSIA
V. Kostylev12 , G. Matyakin3 , J. Mardynsky4 , G. Panshin5 , S. Tkachev6
1

I NSTITUTE OF M EDICAL P HYSICS AND E NGINEERING, Department ofRadiotherapy, Moscow, Russian Federation
A SSOCIATION OF M EDICAL P HYSICISTS OF RUSSIA, Department ofRadiotherapy, Moscow, Russian Federation
3
2C ENTRAL C LINICAL H OSPITAL OF THE P RESIDENTIAL A DMINISTRATION
OF THE RUSSIAN F EDERATION , Department of Radiation Oncology
4
M EDICAL R ADIOLOGICAL R ESEARCH C TR RAMS, Department ofRadiation Therapy, Obninsk, Kaluga Reg., Russian Federation
5
RUSSIAN R ESEARCH X- RAY - R ADIOLOGY, Department of Radiation
Therapy, Moscow, Russian Federation
6
RUSSIAN C ANCER R ESEARCH C ENTER, Department of Radiation
Oncology, Moscow, Russian Federation
2

Purpose: It’s essential to improve the process of radiation oncology modernization in Russia.
Materials: Today 75 percent of 140 radiotherapy departments available inRussia have a very poor level of equipment which doesn’t provide the adequate quality treatment. 20 percent of the departments ensure the satisfactory quality treatment and only 5 percent can deliver good quality radiotherapy. The number of medical accelerators is 10 times less than needed andthe number of medical physicists is 6 times less than necessary. Only 15 percent of medical institutions have adequate medical physics service but only
3 percent (5 centers) provide highly qualified support to international standard. In Russia there is no radiotherapy clinic with the functioning quality
assurance and technical audit systems which could be entitled to the statusof the center of competence in compliance with the IAEA criteria. Becauseof the backwardness in radiation oncology only 30 percent of cancer patients
receive radiotherapy instead of 70 percent requiring it and only 10 percentof them, who undergo treatment in 5 best radiotherapy departments, receive
the adequate radiotherapy treatment, which make only 3 percent of all cancer
patients.
Results: Now the Government of Russia and other former Soviet republics
take active measures in health care modernization, particularly in radiation
oncology. The process of radiotherapy departments’ re-equipment and construction of new radiotherapy centers is essential for the efficient treatmentof cancer patients. However, the modernization doesn’t bring the anticipatedpositive effect today. The situation analysis shows that in most cases the
projects the way they are being realized don’t and can’t bring the anticipatedpositive results and the funds allotted for them are wasted. This situation is
also typical for the former Soviet countries. It’s caused by the serious underestimation of our disastrous backwardness in the atomic medicine, insufficient officialdom competence, lack of scientific guidance, absence of regulation base and above all, the shortage of qualified medical physicists andradiologists.
Conclusions: To liquidate more than 30-year backwardness in this field fromthe highly developed countries we’ll need a 20-year program covering thefollowing measures: elaborate the strategy of radiation oncology modernization and development in Russia establish "growing points" in radiotherapy(technical upgrade of the leading cancer institutions, set-up of education research centers and scientific production associations to produce domestic

S 541

equipment) organize personnel training system, continuing professional development and staff retention system take first aid measures on the systemmodernization of the existing radiotherapy departments construct 500 stateof-the-art radiotherapy centers apply the scientific approach to the planningand design of radiotherapy centers realize the quality assurance program,patient and personnel protection system, scientific and technical audit in radiotherapy elaborate, develop and produce competitive domestic equipment
to cover 50 percent of the Russian radiology market.
1454 poster
SIX YEARS EXPERIENCE OF AN INTERNAL INCIDENT REPORTINGSYSTEM
L. S. M. Conceicao1 , M. Araújo1 , F. Rocha1 , A. C. Oliveira1 , J. Gaspar1 , M.
D. C. Lopes1
1
I NSTITUTO P ORTUGUÊS DE O NCOLOGIA DE C OIMBRA F RANCISCOG ENTIL , EPE, Medical Physics, Coimbra, Portugal
Purpose: The Radiotherapy Department of our hospital has become an active department in ROSIS project during the year 2004. The motivation of
professionals towards this process was based on safety and quality improvement rather than in error and punitive approaching. Since 2005, no reports
have been included in the ROSIS database mainly because of the requirement for English translation. Nevertheless the internal reporting system has
been maintained and actively stimulated. In the present work the experienceof the last six years will be presented and evaluated highlighting its implicationin the overall quality improvement of safety in radiotherapy.
Materials: A report form based on the ROSIS Incident Form was developed
to facilitate the process. The forms are available at each department site(treatment units, simulator, clinical dosimetry, mould room, clinical offices,etc.). They are monthly collected and analyzed. An internal database has
been maintained in order to enable report keeping and global analysis. Most
common reported errors or near misses are discussed at general or subsector meetings where correcting actions are proposed. Whenever a more
serious incident is reported prompt action is carried out. A specific meeting isorganized with the workers involved in the incident and all related professionals. An exhaustive analysis of all the causes and sub-steps of the incident
sequence is done. Correcting actions are taken if possible and preventing
procedures are developed.
Results: In the period from 2005 to 2010, 7845 patients have been treatedin three linear accelerators and 581 incidents have been reported. 88% of
all reports corresponded to near-misses. In the remaining 12% just 3% wereclassified as accidents with significant dose consequences. The radiation
technologists at the treatment units were those that mostly have reported(65%) followed by dosimetrists (20%) and physicists (10%). The areas of error detection were distributed as follows: treatment setup (43%); treatment
plan verification (37%); image acquisition (9%); simulation (6%) and medical appointment (5%). The more severe accidents have systematically been
reduced along the years through active corrective and preventive measures.
Conclusions: Reporting of incidents stimulates alertness, awareness andresponsibility. Periodic evaluation and good communication between professionals is the motor for keeping the process active. The perception and reporting of incidents lead to important changes towards quality and safety.
1455 poster
TLD AUDITS FOR NON-REFERENCE PHOTON AND ELECTRONBEAMS IN RADIOTHERAPY CENTERS IN POLAND
W. Bulski1 , J. Rostkowska1 , M. Kania1 , B. Gwiazdowska1
1
T HE M ARIA S KLODOWSKA -C URIE M EMORIAL C ANCER C ENTER, Department of Medical Physics, Warsaw, Poland
Purpose: The Secondary Standard Dosimetry Laboratory (SSDL) of theMedical Physics Department of the Centre of Oncology in Warsaw has become a member of the IAEA/WHO international network of such laboratories in 1988. The SSDL has been carrying-out external postal TLD audits
in teletherapy centres in Poland since 1991. Regular yearly audit runs havebeen carried out in reference conditions. Yearly audit runs have been extended to non reference conditions since 2003. The results of selected runs,
performed during the period 2005 -2010, are presented.
Materials: TLD system consists of Fimel PCL3 TLD automatic reader,
Niewiadomski & Company LiF: Mg,Ti powder, IAEA holders, IAEA waterproof
capsules, Unidos E with ion. chamber type PTW 30013, water phantom: MT- 150T (Med - Tec) and Co-60 unit - Theratron 780 E (Theratronics).After
successful pilot runs in selected centres, a nation-wide run of the on-axis,
off-axis measurements for symmetric open and wedged fields and for fields
formed by MLC has been performed. In 2009 the run for asymmetric open
and wedged fields were performed.The participants determined the doseswith their treatment planning systems. TLD runs for on axis measurements
in non-reference conditions were performed in Co-60 beams, in X-ray beams
and in electron beams. The TLD capsules were irradiated at 10 cm and 5
cm (or 20 cm) depth for open fields (8x8 cm2 , 10x10 cm2 , 10x20 cm2 ) andwedged field (10x10 cm2 ) in Co-60 and X-ray beams. In electron beams theS 542

QA: I N VIVO DOSIMETRY

QA: I N VIVO DOSIMETRY

TLD capsules were irradiated at depth of dmax for 6x6 cm2 and 10x10 cm2
fields. TLD runs for off-axis measurements in non-reference conditions were
performed in X-ray beams. The TLD capsules were irradiated at 10 cm depth
for symmetric open and wedge fields (20x20 cm2 , +/- 5 cm off-axis). TLD
runs for fields formed by MLC were performed in X-ray beams. The TLD
capsules were irradiated at 10 cm depth for six MLC fields: reference, small,circular, inverted Y, irregular and irregular with wedge. TLD runs for off-axis
measurements for asymmetric fields were performed in X-ray beams. The
TLD capsules were irradiated at 10 cm depth. in various asymmetric set-ups.
Results: The results of the audit in non-reference conditions for on-axis measurements are in the majority of cases within the 3.5% tolerance limit which isusually used for reference conditions.The nation-wide audit, for off-axis symmetric and asymmetric fields and the fields formed by MLC show that it ispossible to keep the dose determination within the 5% limits by implementation of correct methodology and carefully carried-out measurements andcalculations of doses.
Conclusions: The methodology and results of the audit permit to introduce
and maintain the audit program in non-reference conditions, for on-axis andoff-axis measurements and for asymmetric fields, at the national level.

QA: In vivo dosimetry
1456 poster
AN INVESTIGATION INTO THE USE OF IN-VIVO DOSIMETRY FORVARIAN RAPIDARC TREATMENTS
G. Verschoor1 , A. Vinall1
1
N ORFOLK AND N ORWICH U NIVERSITY H OSPITAL NHS T RUST, Departmentof Radiotherapy Physics, Norwich, United Kingdom
Purpose: In-vivo diode Dosimetry for advanced treatment techniques suchas IMRT has been used in this department for the last five years. The Department has recently commissioned Rapidarc (VMAT) treatments on two Varianlinacs. The purpose of this work was to investigate the use of in-vivo Dosimetry techniques (TLD and diodes) to measure the dose delivered using RapidArc treatments. These complex treatments encompass the simultaneous
movement of mlc leaves and gantry rotation so that field size and angle ofincidence are constantly varying. Diodes require correction factors including
field size, SSD, angle of incidence and temperature variation but their application is not straightforward with a rotational treatment technique. Hence, there
is more variation in the measured dose and more scope for differences between planned and measured doses. TLDs require fewer correction factors
but are sensitive to varying amounts of build-up.
Materials: TLDs (Harshaw TLD-100) and diodes (Scanditronix EDP-15) wereplaced at intervals around the phantom. The TLDs had a build up cap or bolus
to measure entrance dose at dmax. A Varian Clinac 2100EX was used to deliver rotational fields in clinical mode. Initial work has focused on a square fieldrotating around a cylindrical phantom (arc <180 degrees so that the dosimeter is not exposed to exit dose). Various arc angles and field sizes have been
investigated. The raw dosimeter reading was corrected with an appropriate
calibration factor and for the diode a correction factor for SSD. A comparison was made between the dosimeter reading and the value predicted by thetreatment planning system (TPS).
Results:

1457 poster
DOSI-SECURE® : A NEW WIRELESS IN VIVO DOSIMETER FOR
EXTERNAL RADIOTHERAPY
G. Hangard1 , A. Canals2 , G. Sarrabayrouse3 4 , D. Lavielle2 , C. Chatry2 , A.
Laprie1
1
I NSTITUT C LAUDIUS R EGAUD, Toulouse, France
2
TRAD, Labége cedex, France
3
U NIVERSITÉ DE TOULOUSE ; UPS, INSA, INP, ISAE ; UT1, UTM, LAAS
; F-31077, Toulouse Cedex 4, France
4
CNRS ; LAAS ; 7 AVENUE DU COLONEL R OCHE , F-31077, Toulouse
Cedex 4, France
Purpose: We develop a new radiation dosimeter, named DOSI-SECURE®.
He is dedicated to measure the entrance dose with a wireless reader andwithout specific calibration during radiotherapy treatment. This study concerns both evaluation of intrinsic parameters of the sensor under different irradiation configurations and preliminary tests using DOSI-SECURE®prototype.
Materials: Intrinsic parameters have been validated with sensors packaged
on Dual In Line (DIL) connected to a Source Monitor Unit (SMU) outside thetreatment room. The dose measurements have been accomplished in a solid
water equivalent phantom (PMMA) for photon beams of 6 and 18 MV (Clinac,
Varian®). The tests were done under reference conditions: SAD of 100 cm,
depth of 5 or 10 cm according to the energy and a field size of 10x10 cm.
Initially, we began by defining the best reading time after irradiation by measuring a dose at 30 s and every minute up to 10 min. Then, we establishedthe calibration curves for up to 300 dosimeters in order to evaluate stability
and sensitivity of the response for a dose ranging from 0.5 to 20 Gy with stepsof 0.5 Gy and 1 Gy. After that, we studied the response variation with clinical parameters (field sizes from 4 to 40 cm2 and SSD between 80 and 120cm) and compared the depth curves achieved with an ionisation chamber.
For the preliminary tests, we used the system completely, i.e. a skin patchwith the sensor and a wireless reader. This detector incorporates a RFID
(Radio Frequency Identification) system, with a PMOS dosimeter (P-channel
Metal Oxide Semiconductor). Each detector will be associated to a patient
and will record physically the dose received. The preliminary tests consisted
in evaluating the variation of the dose response function to the beam angle
variation.
Results: The minimum time of reading after irradiation is 1 min. There isno significant difference between 1 and 10 min (<0.3 %). This result gives
easily the possibility to use this sensor in a clinical routine. For a dose of
7 Gy, the fading after 150 h is less than 2 % and for a dose of 20 Gy, it
falls in 1% after 500 h. The calibration curves (Figure 1) for 27 components
with 0.5 Gy steps measurements shows a sensibility of 4mV/cGy at 1 Gy
for 6 MV. The dispersion increases with the cumulated dose and the sensor
saturation is more than 80 Gy. For the field size and for the SSD variations,the dose is less than ± 5 %. The depth curves for 6 and 18 MV match with
the ionization chamber curves and the values are less than ± 2 % except
in the first centimetre due to the build up. With the prototype, the response
is less than 2 % between ± 20◦ , 5 % at ± 30◦ and more than 15% at ±50◦ . This anisotropy shows in such point users will take precautions during
measurements on a patient.

1. TLDs under bolus show good agreement (within ±5%) compared with
the TPS,
2. Good agreement between TPS and the diode or TLD build up cap
results were obtained by creating a plan with the build up cap/diodeexplicitly included.
3. When the build up cap/diode is included in the plan the agreement between the predicted TPS value and dosimeter reading improves from
15% to 4% for the TLDs, and from 20% to 6% for the diodes.
Previous work in this department has indicated that it is possible to obtain
results of measured v predicted doses within ± 5% for static IMRT fields
with both diodes and TLDs. However, this is obtained by accurately positioning the dosimeter at a point of high dose and low dose gradient within thetreatment field. Early results for Rapidarc fields on a cylindrical phantom andthe dosimeter on the central axis have indicated measured doses of the order of 10-12% variation from predicted. Further work investigating different
Rapidarc fields with varying modulation on both a cylindrical and a Rando
phantom will be presented.
Conclusions: Early investigation of both TLDs and diodes for the use of invivo dosimetry for Rapidarc is promising. However, because it is not possible
to apply correction factors in the conventional way for diodes a wider tolerance
level is proposed.

Conclusions: These first results show a good reproducibility of the dose
response as well as a stability of measurements in time. The sensitivity
observed with the DOSI-SECURE®dosimeter are suited to realize in vivo
dosimetry during radiotherapy treatments and allows to confirm the interestof continuing the development of such a system.
1458 poster
DOSIMETRIC CALIBRATION OF AN EPID USING THE ‘PORTDOSE’
PORTAL DOSIMETRY SOFTWARE
P. Rixham1 , P. Crean1 , S. Weston1 , V. Cosgrove1
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom

Purpose: In vivo dosimetry is becoming an essential component in a comprehensive radiotherapy service. Amorphous silicon (a-Si) EPIDs used for dosimetric purposes offer a solution to in vivo dosimetry. EPID dosimetry software
has been produced by the Nederlands Kanker Instituut (NKI), Netherlands.
The software uses the EPID signal and a back projection method to calculate
a 2D dose distribution at the isocentre of the patient. This calculated andplanned dose distribution can then be compared. The software was designed
for use with the panel setup at the NKI, which includes specific acquisition
software and a 2mm copper plate which sits on top of the a-Si plate of thepanel. This work describes the initial commissioning of the software for an
Elekta iViewGT portal imaging panel and phantom measurements made toverify the calibration.
Materials: An iView EPID panel was calibrated for a 6MV photon beam by acquiring several series of images and ion chamber measurements for a rangeof square field sizes and phantom thicknesses. The software automaticallyprocessed the images and chamber readings to produce a calibration for thepanel. The calibration was then tested via series of phantom irradiations.
The calibration was tested for varying thicknesses of WTE for a range of fieldsizes. The effect of the wedge and SSD were also investigated. A standard
8-field 3D conformed prostate plan was adapted to 6MV and delivered to ahomogenous phantom. This was repeated with two inhomogeneous phantoms which simulated the effect of femoral heads. Finally three patient’s headand neck IMRT treatment plans were transferred onto a homogenous phantom and delivered. In each case the calculated portal dose was compared tothe planned dose and the dose measured by an ionisation chamber placedat the isocentre.
Results: Measurements were taken and the panel was successfully calibrated. The isocentric dose calculated for the various square fields and phantom thicknesses matched the measured dose to within 2.5%. Lower fieldsizes had over 90% of pixels passing a gamma tolerance of 3%/3mm. Thisvalue dropped at larger field sizes. The software showed poor agreement
to measured doses for wedged fields. For the prostate plan, the majority offields were within 3%, with discrepancies above this explained by the presence of the wedge or by ghosting within the panel. Similar results were foundfor inhomogeneous phantoms. All of the IMRT fields were within 5% of theplanned dose, and the total treatment dose was within 1.5%.
Conclusions: The EPID was successfully calibrated for a 6MV photon beam,and validated by phantom treatments. Errors caused by ghosting can besolved by increasing the delay between acquisitions. Further development of
the software is required to solve issues with wedged fields. This work showsthat the software is viable for use with iView configurations that differ from theNKI.
1459 poster
DOSIMETRIC VERIFICATION OF TREATMENT FIELD JUNCTION IN
CRANIOSPINAL TREATMENT WITH GAFCHROMIC-RTQA® FILM
P. Eichberger1 , B. Schiestl1 , T. Daliot1 , P. Lukas1
1

M EDICAL U NIVERSITY I NNSBRUCK , D EPARTMENT FOR T HERAPEUTICR ADIOLOGY AND O NCOLOGY, Innsbruck, Austria

Purpose: Despite of availability of modern high-end radiation treatment
techniques complex target volumes like craniospinal tumors require special
attention on correct positioning of treatment fields due to usually necessary junction of several radiation fields and avoidance of gaps or overlaps.
GAFCHROMIC-RTQA® -film was tested under experimental and clinical conditions regarding its usability as a dosimetric medium for visual evaluation oftreatment field junction and optimization of patient or treatment field position,
respectively in clinical routine.
Materials: After dosimetric calibration of a GAFCHROMIC-RTQA® -film / EPSON EXPRESSION XL 10000 dosimetric system the visual detectable optical resolution was determined under optimized conditions by irradiation offilm material positioned by use of an ELEKTA-HexaPODTM -system with defined gap or overlap of junctioning radiation treatment fields. Reachable determinable resolution under realistic treatment field conditions was evaluatedby simulating a craniospinal radiation using a ScandiDos Delta4® -system andcomparison of dosimetric data with results from irradiation of film material
simultanously placed on the surface of the phantom. For two patients undergoing craniospinal radiation treatment GAFCHROMIC-RTQA® -film was usedfor visual evaluation of treatment field junction and optimisation of patient or
treatment field position, respectively.
Results: Using GAFCHROMIC-RTQA® -film for visual evaluation of treatment
field junction gaps or overlaps can be recognized down to ±0.2 mm under optimal conditions. Phantom measurements reproducing realistic treatment field conditions increase the visual determinable resolution to ±1 mm
due to suboptimal dose ratios at the position of the radiochromic film located on the phantom surface preventing optimal film contrast. Dosimetricdata measured with radiation detectors placed in the volume of the ScandiDos Delta4® -system are in accordance with results from visual film evaluation.Using GAFCHROMIC-RTQA® -film during patient treatment gaps andoverlaps of junctioning treatment field were determined by visual evaluationof irradiated film material in the range of 0 to ±4 mm during the first treatments. Based on this results adaptation of patient or treatment field position,
respectively reduced the gap or overlap to less than ±1 mm in average.

S 543

Conclusions: GAFCHROMIC-RTQA® -film can be used for verification oftreatment field junction and visual evaluation. Using GAFCHROMIC-RTQA® film during radiation treatment of craniospinal tumors for visual evaluation ofgaps or overlaps can be used for optimization of treatment.
1460 poster
IN-VIVO DOSIMETRY USING AN AMORPHOUS SILICON EPID
J. Burnley1 , M. Ramtohul1 , M. Tiffany1
1

H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Department of Medical Physics and Radiation Safety, Birmingham, United Kingdom
Purpose: As part of working towards safer radiotherapy a number of key reports have recommended the use of in-vivo dosimetry (IVD) monitoring at the
beginning of treatment for all patients. A variety of methods exist to perform
IVD including using diodes, MOSFETs, TLDs and measurements made using
ion chambers. An alternative approach is to use an electronic portal imaging
device (EPID) to measure the transmitted fluence and correct this back to thedose at a particular plane within the patient.
Materials: An ElektaTM iViewGTTM EPID was commissioned for in-vivo
dosimetry at 10MV by relating the pixel value measured at the centre of thedevice to the absolute dose measured by an ion chamber at the midpoint ofa water equivalent phantom. A utility was written within MATLABTM to import
DICOM RT data from the XiO® planning system and automatically extract
the midpoint dose and patient thickness at the beam central axis. These aresubsequently used to predict the delivered dose based on an EPID image
acquired during treatment.
Results: Verification measurements made following commissioning using a
range of phantom thicknesses, SSDs and field sizes indicated an accuracyof approximately 5%. An initial trial of patients undergoing prostate radiotherapy gave good agreement with the treatment planning calculated dose. An
average error of -1.0% was observed for the ant-post beams, lateral beams
exhibited an average error of -5.1%.
Conclusions: Through a series of commissioning measurements and following clinical implementation on a sample of patients undergoing radiotherapyof the prostate, the iViewGTTM EPID has been shown to be sufficiently stable
and accurate for use as an in-vivo dosimeter. It is expected that differences
between the dose measured for the ant-post and lateral beams may be due
to increased attenuation within the femoral heads which is not accounted forusing this method. An additional factor may be used to correct for this which
may subsequently extend this form of IVD to a number of additional treatmentsites.
1461 poster
RECONSTRUCTION OF RADIOTHERAPY ISOCENTRE DOSE FOR
DIFFERENT MANUFACTURER LINACS, USING A GENERALIZEDPROCEDURE
A. Fidanzio1 , P. Angelo1 , S. Cilla2 , F. Greco1 , L. Azario3 , M. T. Russo4 , D.
Sabatino1 , G. D’Onofrio5 , A. Russo6
1
UCSC, Physics, Roma , Italy
2
U NIVERSITÀ C ATTOLICA DEL S. C UORE, Physics, Campobasso, Italy
3
P OLICLINICO U NIVERSITARIO "AGOSTINO G EMELLI ", C ATHOLIC U NIVER SITY , Physics, Roma, Italy
4
O SPEDALE B ELCOLLE, Health Physics, Viterbo, Italy
5
O SPEDALE C IVILE S ANTO S PIRITO, Health Physics, Pescara, Italy
6
USI, Radiotherapy Department, Rome, Italy
Purpose: Aiming to simplify in-vivo transit dosimetry commissioning and to
reduce the time needed for data analysis, a generalized procedure to reconstruct the isocenter dose, Diso, for 3D conformal radiotherapy (3D-CRT) has
been developed for X-ray open and wedged beams. The method was developed to work with linacs by different manufacturers (Varian, Elekta andSiemens) and equipped with aSi Electronic Portal Imaging Devices (EPIDs).
The present work reports the results of a multicenter application.
Materials: Using water-equivalent solid phantoms of different thicknesses, w,
and photon square fields of sizes, L, generalized mid-plane doses and generalized EPID-transit signals, by 57 beams of 8 different linacs, were fitted withthree-dimensional polynomial functions. In particular, 19 open beams werecharacterized in terms of TPR20 10 , while 38 wedged beams were characterized in terms wedge attenuation factor WAF.The in-vivo dosimetric procedure
was applied in 8 radiotherapy centers for pelvic, thorax, breast and head 3DCRT treatments. Tolerance levels of ±6% for the thorax treatments and ±5%
for all the other treatments, respectively, were estimated for index R, definedas the ratio between the reconstructed dose, Diso, and that computed by
the TPS, Diso,TPS. A dedicated software DISO, interfaced with the Record& Verify system in use in each center, was developed to automatize in-vivo
dosimetry analysis.
Results: Using the generalized polynomial functions, the time needed forin-vivo dosimetry commissioning was essentially reduced to that required for
EPID calibration in a reference condition. About 25 s per beam, after therapy
session, were sufficient to display the reconstructed doses and the transit

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signal profiles crossing the beam central axis. About 3000 fields for 250 patients were checked in the 8 mentioned centers, using 5 Varian, 4 Elekta
and 6 Siemens linacs. The observed discrepancies were essentially due topatient’s set-up errors, patient’s morphological changes, and TPS implementation errors.
Conclusions: The results of the multicenter application have been used todevelop some action-guidelines for the out of tolerance checks. The good
dosimetric accuracy of the generalized procedure here reported suggested
us its extension for Intensity Modulated Radiotherapy beams and some preliminary results are here reported.

Results: The mean skin dose (Table I) measured at umbilicus of every patients was 104% (range 95% to 116%, SD=5%) of the prescribed dose. In
majority of the patients (67%) the dose to the umbilicus was within ±5%of the prescribed dose, while in 23% patients the variation was within 10%.
Only in two (10%) patients the dose to the umbilicus was more than 10%(Maximum 116%) of the prescribed dose. The mean dose to majority of themeasurement locations such as forehead, SSN, Xiphoid, Axilla, palm and lateral thigh was within ±5% of the prescribed dose. Though the variations inmean dose from the prescribed dose are similar at these anatomical locations
as compared to umbilicus, the variation amongst patients varies widely for
anatomical locations like axilla, palm and thigh. However, deviations of 106%
(SD=9) and 107% (SD=12) were demonstrated in the mean dose to west andknee respectively while higher deviation of 118% (SD=6) in the mean dose
was observed at foot (mid dorsum). A maximum variation with mean doseof 75% (SD=9) from the prescribed dose was observed in inner thigh. The
underdose observed in the inner thigh region could be primarily due to thepartial self shielding and tangential irradiation. The wide ranges of deviation
observed in the mean axilla dose (67% - 129%) from the prescribed dose
could be mainly due to the variation in the patient set up. The overall X-ray
contamination was approximately 1.0%.

1462 poster
THE USE OF GAFCHROMIC® EBT2 FILMS FOR DAILY ABSOLUTEDOSE VERIFICATION ON 3D TREATMENTS. A PRACTICAL CASE
ON A KAPOSI’S SARCOMA.
L. Pereira1 , F. Del Moral1 , E. Meilan1 , J. C. de Azevedo Gomes2 , A. G.
Teijeiro Garcia1 , B. Andrade Alvarez3 , J. Vazquez4 , I. Nieto5 , D. Medal1 , A.
Lopez Medina3 , S. Francisco3 , M. Salgado3 , V. Muñoz3
1
H OSPITAL DO M EIXOEIRO, Servicio de Radiofísica, Vigo (Pontevedra),Spain
2
E SCOLA S UPERIOR DE T ECNOLOGIA, Lisboa, Portugal
3
H OSPITAL DO M EIXOEIRO, Vigo (Pontevedra), Spain
4
H OSPITAL DO M EIXOEIRO, ., Vigo (Pontevedra), Spain
5
MEDTEC, Vigo (Pontevedra), Spain
Purpose: Gafchromic®EBT2 films are widely used to measure relative dose.
Their excellent properties like a high spatial resolution or a precise dose response at wide energy range with low energy dependence allow their use inmany applications within RT. Although film dosimetry is mostly used for relative dose, it is possible to be used to determine absolute dose. The aim of thiswork is to show a practical example of use of EBT2 films for in vivo dosimetry
in a cutaneous kaposi’s sarcoma
Materials: RT is a therapeutic treatment that sometimes can be combinedwith chemotherapy. In this case, dose delivery was 30 Gy in 10 fractions of
3 Gy, the patient was reclined in supine with his ankles in water. Water bathhomogenizes dose and ensures proper positioning. Unfortunately the size of
the water bath does not allow the realization of a CT scan since its dimensions are greater than the FOV of the CT scan. UM calculations have been
done carried out with a TPS XIO®release 4.60.00, Treatment was carried out
with 6MV photon and two lateral oppsed fields at SSD 93cm and the field size
is 15 cm x 20 cm, irradiating both ankles in the water bath. Prescription point(300 cGy) is defined in a depth of 14 cm for both sides (left and right).The
EBT2 films were cut into pieces 25 cm long and 4 cm width and wrapped intopolyethylene films to protect them from skin and water in the order to avoid
additional optical density changes which can introduce an additional uncertainty on dose measurements. Films were rolled around the ankle and a point
was marked so that we could have a reference point. 24 hours after treatment
delivery, films were scanned five times and averaged with a home-made software on red channel to reduce noise, nonuniformity of the scanner have beentaken in account and corrected by software. Finally a dose distribution has
been obtained along the length of the film, which coincides with the perimeter of the patient’s ankle. Analysis of the measurements were analyzed with
IMRT OmniPro®.
Results:

S 545

Results: The time for processing 100 slabs of 256*256 pixels, including thetransformation to a 256*256*256 grid, using a single core from an Intel E6750
cpu @ 2.66 GHz, is now only 4.5s, which is a factor of 2 faster than the originalcode. The processing time dropped to 2.4s on a single core of an Intel I7 920
cpu at the same clock rate. A first effort to parallelize the code, using multiple
processes, one on each of the eight cores of this cpu, resulted in a processing
time of 0.7s. Speed improvements from full 3D algorithms that make use of
3D scattering kernels were not observed. We expect that our new "2.5D"
algorithms can be parallelized more efficiently and that the code for the affine
transform can be further optimized. Consequently, the processing of 100
slabs in less than 0.3s on dual quad core machines is feasible.
Conclusions: Real time processing of EPID dose reconstruction in 3D isfeasible on a normal CPU.

QA: of equipment
1465 poster
A GRAPHICAL TOOL FOR MLC QUALITY CONTROL OF EPID
IMAGES
T. Ventura1 , M. D. C. Lopes1 , M. Capela1
1
I NSTITUTO P ORTUGUÊS DE O NCOLOGIA DE C OIMBRA F RANCISCOG ENTIL , EPE, Medical Physics, Coimbra, Portugal

A good agreement between TPS calculations and averaged measurementsfrom different fractions were obtained. Dose profiles from different fractions
are showed on the upper figure. Slight differences due to small displacementsof the ankle into the water bath and the set of films can be seen. In the lower
figure, calculated dose in several points by TPS are compared to averagemeasured dose in the film in several points.
Conclusions: There is a good agreement between measurements and calculation. Film dosimetry can be used for in vivo dosimetry, and is speciallysuitable for complex treatments and for skin dose determination.This research
was supported by Consellere Econom Industria of Xunta de Galicia (Spain),under Grant 09SIN007CT.
1463 poster
TOTAL SKIN ELECTRON THERAPY: IN-VIVO DOSIMETRIC DATAANALYSIS OF FOURTEEN YEARS
R. Kinhikar1 , S. Chaudhari1 , C. Tambe1 , D. Deshpande1
1
TATA M EMORIAL H OSPITAL, Medical Physics, Mumbai, India
Purpose: To report in-vivo measured doses using thermoluminicent dosimeter (TLD) on patient undergoing Total Skin Electron Therapy (TSET) for mycosis fungoides.
Materials: 38 patients [24 Male and 14 Female] underwent TSET between
March 1996 to December 2010 on linear accelerator (Varian, USA). The
TSET was carried out according to the modified Stanford technique, delivering a total dose of 30.6 Gy in 17 fractions using an electron beam with anominal energy of 6 MeV. Each patient received a dose of 1.2 Gy/field/day at
a treatment distance of 4.93 m. A perspex scatterer-degrader of 2 mm thick
was used at a distance of 30 cm from the patient’s skin. There were 6- fields
i.e. anterior, posterior, left and right anterior obliques, and left and right posterior obliques in both the upper and lower parts of the body. The eyes and thenails were shielded at each session of radiotherapy (RT). Thermoluminescence dosimeters (TLD) were placed [LiF:MgTi] at 12 different body points(forehead, SSN, Xiphoid, Axilla, palm, Umbilicus, west, thighs and knees) for
every patient. The dosimeters were read with UL-320 (Rexon, USA) reader
24 h post irradiation. The overall dose uniformity across the body is reported.

Conclusions: TSET is a very effective, but technically difficult therapy formycosis fungoides. Results of in-vivo dosimetry revealed acceptable dose
homogeneity. In vivo dosimetry, using TLD is a reliable and cost-effective
method for the quality assurance of dose delivery on patient for such special
RT procedure.
1464 poster
TOWARDS CALCULATING 3D DOSEPORTAL DOSIMETRY IN REAL TIME
H. Spreeuw1 , M. van Herk1 , R. Rozendaal1

DISTRIBUTIONS

FROM

1

T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiotherapy, Amsterdam, Netherlands

Purpose: The multileaf collimator (MLC) is one of the most critical components of a radiotherapy linac. Its precision and reproducibility are essential
not only for IMRT but also for 3DCRT techniques. Quality control tasks should
be regularly performed to ensure that the leaf positioning and reproducibility
are according to the specifications.EPID images are a good alternative to film
for the quality control routine of the MLCs. Their fast acquisition and visualization enables the implementation of a great number of quality tests in order
to assess geometrical accuracy of the MLC. However the visually inspectionof the images is just qualitative. In this work we will present a computational
tool dedicated to the analysis of EPID images.
Materials: The daily quality control of the 82 leaves Optifocus MLC of theOncor Avant-Garde (Siemens) linear accelerator includes the "garden-fence"(21 segments of 2 mm interspaced by 10 mm) EPID images acquired with
the Optivue 1000 flat-panel. The same pattern is acquired for the Y-jaws,
after each MLC calibration, for reference purposes.A tool was designed andprogrammed in Matlab environment (version R2010a) to analyze the "gardenfence" DICOM files. The deviation from the correct position of each leaf along
the entire travelling range is calculated after correction for image rotation. For
the Y-reference image, the jaw positions were calculated for each field segment by the estimation with a sub-pixel accuracy of the coordinates of the
FWHM of the intensity profile. For each leaf in the MLC images, the same
approach was followed. The deviation of each leaf is obtained by comparison with the position of the Y-reference images. A visualization module wascreated to enable a fast overview of the MLC status.
Results: This new analysis tool was included for EPID images of the weekly
MLC quality control. The graphical output of the analysis includes a color
code with three ranges: green, within tolerance (deviations less than 1 mm),yellow, deviations between 1 and 1.5 mm and red for deviations larger than
1.5 mm (Figure 1). The same color scheme is used to visualize the drift ofeach leaf with time and enables the decision upon the need for MLC calibration.

Purpose: In-vivo dosimetry using electronic portal imaging devices (EPIDs)
has been shown to be a valuable and efficient QA tool in external beam
RT. For hypofractionated cases, it is, however, still required to perform pretreatment validation. Ultimately, the dose reconstruction should be real-time,allowing detection of any errors occurring during delivery of large fraction
doses. However, currently calculation of 3D dose distributions from one EPID
image takes much longer (+/- 10 s) than the framerate of the detector (0.3s).
We investigated further optimization of the present algorithms in order toreach real-time processing speeds. The present algorithm works in "2.5D",
which loops over the slabs in a 3D volume. The dose calculation includes theapplication of the inverse square law, convolution with a 2D kernel and interpolating the 3D distribution to a larger grid, by applying an affine transform.
Materials: We profiled our new code on two different CPUs. Table 1 lists
the processing time of the various components of the optimized algorithm.
The optimizations arrive from a redesign of the dose engine code using
Python/Numpy/Scipy, removing superfluous operations, the application of adifferent FFT method (FFTW) as well as the Numexpr package to evaluate
numerical expressions efficiently.

Conclusions: This tool became very useful in the quality control of the MLC.
It allows a fast and accurate analysis of the MLC status and a chronologicalS 546

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overview of the leaves deviations from the reference frame over time. Thisapplication can also be easily extended for different field patterns.
1466 poster
A PHANTOM-BASED QUALITY ASSURANCE WORKFLOW FORCHECKING THE PATIENT POSITIONING PROCEDURE
N. Koch1 , C. Scherf1 , J. Licher1 , J. Liebich1 , E. Kara1 , C. Rödel1 , U.
Ramm1
1
K LINIKUM DER J OHANN W OLFGANG G OETHE U NIVERSITÄT, Klinik fürStrahlentherapie und Onkologie, Frankfurt, Germany
Purpose: Dose application according to the radiation treatment plan requires
an accurate patient positioning. The positioning in the treatment room isbased on a reference point defined in the planning CT-dataset and marked
on the patient skin. For defining and marking this reference point a laser system and a moveable table are required. An additional imaging system in thetreatment room, e.g. an EPID, is essential for accurate patient positioning.
This paper introduces the development of a phantom and its introduction into
a quality assurance (QA) workflow for checking these systems, which influence the patient positioning.
Materials: For the phantom development gold-, tungsten-, steel spheres and
BEEKLEY CT-SPOTS® were tested in regards to their imaging qualities on
CT- and EPID-images.For evaluation of the QA workflow a CT was used,which is equipped with a movable table, a laser marking system and an integrated TPS. The TPS enables the location and defining of reference points
and communicates these to the laser system for an exact coordinate transfer.
Furthermore another TPS, a Linac equipped with an EPID and an oncology
information system (OIS) were used.
Results: A cubic phantom, consists of PMMA-slabs, was developed to perform the QA workflow. CT-SPOTS® and tungsten-spheres were found topresent best the reference-point and the treatment isocenter. For the verification parameters, the geometric center-points of the spheres and CTSPOTS® are marked on the phantom surface. The phantom contains additional tungsten-spheres representing an anatomic structure. The QA workflow starts with the acquisition of a CT-dataset of the phantom. Subsequently
a reference point (CT-SPOT® ) is defined in this dataset and transferred to thelaser system. It will be assessed if the laser lines correspond with the marked
center-point of the CT-SPOT® . This is to verify the communication between
the TPS and the laser system. With another TPS, the treatment isocenter isdefined and a verification plan including DRRs is created. The positioning on
the Linac is checked visual and furthermore with the OIS taking EPID-images.
By means of the positioning of the anatomic structure (tungsten-spheres) in
relation to the treatment isocenter, the OIS can calculate the shift between
the actual positioning (shown on the verification images) and the planned positioning (shown on the DRRs). The evaluation of the QA workflow reveals
that the precision of the process is limited, as expected, due to the resolutionof the CT-images. This is equivalent to the precision of the patient positioning
under ideal conditions. Furthermore the evaluation reveals that the QA workflow is very sensitive on systematic errors of the used systems for the patient
positioning.

1467 poster
AN ANALYSIS OF THE LONG TERM PRECISION OF MLC IN
DYNAMIC IMRT THROUGH DAILY ROUTINE MLC QA
M. Yamada1 , O. Kunio1 , K. Kai1 , K. Matsuda1 , K. Iwasaki1 , S. Kuroda2 , S.
Takahashi3 , N. Uchida3 , K. Tateoka4
1
S HIMANE P REFECTURAL C ENTRAL H OSPITAL, Radiological Technology,
Izumo, Japan
2
S HIMANE P REFECTURAL C ENTRAL H OSPITAL, Radiology, Izumo, Japan
3
S HIMANE U NIVERSITY FACULTY OF M EDICINE, Radiology, Izumo Shimane,Japan
4
S APPORO M EDICAL U NIVERSITY S CHOOL OF M EDICINE, Radiology,
Sapporo, Japan
Purpose: MLC(multi-leaf collimator) position accuracies as well as early detection of MLC motor failure or its deterioration is important issue for dynamic
Intensity Modulated Radiotherapy (IMRT). The purpose of this study was toinvestigate the temporal precision of each MLC position and its motor deterioration according to our original quality assurance (QA) program for routine
practice in our hospital.
Materials: We have used Trilogy system (Varian) with 6 MV and 10 MV photon beams. Three different MLC sweep test patterns were created by changing MLC travel speed, respectively. All three fields were irradiated by threedifferent gantry angles of 0 degree, 90 degree and 270 degree as daily routine
QA. During August 2009 to October 2010, 1646 MLC log files were recordedby the QA program. Actual MLC position of Bank A, Bank B and gap errors
compared with planned position were analyzed by a program (Matlab ver.
7.1, Cybernet Inc.) for each MLC. Then average and maximum RMS andstandard errors as well as systematic and random RMS errors in each MLC
were also determined by every month.
Results: The overall maximum RMS errors of all MLC and MLC gap were
within 0.26 cm and 0.14 cm, respectively. The overall maximum standard
errors of all MLC and MLC gap were within 0.07 cm and 0.02 cm, respectively. The amount of errors was relatively large when the gantry angle was
270 degree was used compared to other two different angles. The accuracyof MLC position was also depended upon its travel speed. From the correlation between RMS errors and standard errors of MLC, we could monitor thetendency of MLC motor deterioration using above temporal data.

Purpose: To compare and evaluate the practical challenges and workflow issues during simultaneous commissioning of Varian Novalis Tx (NT) machine
and a Helical Tomotherapy (HT) machine.
Materials: An experienced team of physicists prospectively compared thecommissioning details of the two machines. Detailed comparison of machine output checks, multileaf collimator (MLC) performance, laser alignment
checks, mechanical accuracy checks, isocentre, MLC checks and the imaging tests were analysed with procedural details and timed comparison of theprocesses was done. Image detection, resolution and on board imaging tests
including dosimetric tests were done. Primary and secondary beam checks
were required for HT. Tests for alignment check; stability verification including rotational MLC tongue and groove, jaw shift, central axis divergence was
done.
Results: Overall commissioning time for HT was 18 days versus 26 days for
NT. It was longer to commission NT with different field sizes used for PDD,
flatness, symmetry whereas in tomotherapy the PDD was 1cm, 2.5 and 5cm.
The Phantom used in varian was different from that HT where commissioning
required X profiles , Y profiles and diagonal X and Y profiles to analyse flatness for all directions .Different isocentre distance was maintained with bothNT(100cm) and HT (85cm).Difficultly was faced in the phantom supplied by
HT ( 2D RFA) as it has to be manually shifted each time to measure longitudinal and transverse profile. In beam analysis, the varian photon beams
required flattened beams and longer time for tuning whereas HT did not require flattened beam, and the beam was forward peaked. Data for individual
tests will be summarised for both NT and HT.
Conclusions: HT and NT are different systems requiring diverse QA andcommissioning. Whilst HT commissioning took less time the tests for NT
were more extensive. Centres willing to choose a new high end machine
and interested in the commissioning algorithm will benefit from the practicalpresentation.
1470 poster
COMPARISON OF PHOTON BEAM DATA AND BEAM MODELINGRESULTS FOR TRUEBEAM, TRILOGY AND CLINAC 2100 LINEAR
ACCELERATORS
G. Beyer12 , J. Pursley2
1
2

Conclusions: In this study, our original QA program could identify temporal
MLC position accuracies for IMRT. We could also specify the deterioration ofsome MLC motors. The relationship between the amount of analyzed MLC
error and the operating point of hardware MLC interlock should be further
investigated.
1468 poster
ANCIENT WAYS, NEW INSIGHTS IN ROTATION ACCURACY
M. van het Loo1
1
ARTI - A RNHEMS R ADIOT HERAPY I NST., Arnhem, Netherlands

Conclusions: The specified phantom combined with the QA workflow is aquick and appropriate method for a routine QA of the systems used for theaccurate patient positioning.

Materials: A set of measurements is composed to determine the rotation accuracy in reasonable time. Only four self-developing Gafchromic EBT2 films
are necessary for constancy check. Six to nine beams of 6 MV and 120 MU
are used for each film. Gantry sag and the asymmetry of the collimator canbe combined in one measurement. The analysis separates the asymmetry of
the collimator and the gantry sag afterwards.

Purpose: Star shot films are commonly used to determine the isocentric accuracy as part of the geometrical checks of linear accelerators. Radiographic
films are irradiated with small elongated fields using various angles (star shotor spoke film). The beam axes intersect close to the radiation center andforms a certain pattern. This pattern is used to determine the rotation accuracy and the position of the rotation center of collimator, gantry sag, gantry
wobble and the table in both directions. If stereotaxy is introduced a highly
accurate determination of the rotation errors is required. Aim is to develop an
automated fast and accurate method for analyzing the rotation errors with thepossibility to differentiate between different sources of errors.

S 547

The figure shows a spoke pattern of the table. The top faces the facia wall.
Due to the restricted rotation of the table the radiation center (x) and therotation center (*) do not correspond. Using the spoke pattern the position of
the rotation center with associated error is determined.A rotation can containdifferent sources of errors. The error of the table rotation is composed of themisalignment in the table and the collimator, table sag and also the focal spot
position. Differentiate between these sources of errors is a challenge. The
sagging causes a shifting rotation center, which results in a scattered spoke
pattern. Errors, which are caused by sagging and positioning, do not simply
add up. The simulation of spoke pattern can help to separate these sourcesof errors. Several possible varieties of a shifting rotation center were used toiteratively found the best matching spoke pattern.
Results: In a 6 months period the measurements were performed at least
10 times for each rotation. A measurement inclusively scanning and analyzing took approximately 10 minutes per rotation and the standard deviation of
the error for each rotation was 0.05 mm or lower.Simulations showed a good
agreement with measured spoke patterns and gave more insight in the composite and influences of each error. Differentiate between composite errors
by simulation took some time extra.
Conclusions: The described method for analyzing the star shot film is a robust and accurate method for determining the rotation accuracy of the linac
in reasonable time. Simulation gives insight into the sources of rotation errors and gives the possibility to tightening the geometrical accuracy of thestereotactic linac.
1469 poster
COMPARING WORKFLOW AND COMMISSIONING IG/IMRT CAPABLE MACHINES:NOVALIS TX VERSUS TOMOTHERAPY
S. Prasath1 , A. mahata1 , I. Mallick1 , R. Achari1 , S. Chatterjee1
1
TATA M EDICAL C ENTER, Kolkata, India

M EDICAL P HYSICS S ERVICES I NTL LTD, Cork, Ireland Republic of
M EDICAL P HYSICS S ERVICES, Tampa, USA

Purpose: To evaluate the beam data measurements for two standard photon beams from the new Varian TrueBeam linear accelerator (linac) and tocompare that data to beam data obtained from Trilogy and a Clinac 2100C
Varian linear accelerators. three different photon beam data sets were used
to generate the AAA Eclipse model and to compare the resulting algorithm
modeling parameters.
Materials: Measurements of PDDs, profiles, and output factors were performed on three Varian linear accelerators with 6 MV and 15 MV photon
energies. The measured data was then used to configure the AAA photon
algorithm in the Eclipse treatment planning system. An evaluation of the resulting parameters in Eclipse was performed to evaluate the effects of any
differences between the data sets obtained from the machines.
Results: PDD data showed less than 1% variation between the linear accelerators. Data from the Clinac and Trilogy were almost identical (less than 1%
variation on profiles and output factors). All square field profiles showed almost identical profile shape for all three machines (variation <1%). The dataobtained from the TrueBeam showed some small variations in the output factors and some variations in the shape of the diagonal profile as compared to
the Trilogy and Clinac. The output factor differences were found mainly forsmaller and larger field sizes, with observed differences of less than 2% ascompared to the other 2 linear accelerators. The TrueBeam’s output factor
varied less as a function of field size, especially for the 6 MV beam. The
diagonal scans demonstrated a difference in the profile shape at a distancegreater than 20 cm from the central axis, especially for the 15 MV energy.
These differences were probably caused by the wider primary collimator in
the TrueBeam as compared with the Trilogy and Clinac. The final results for
the Eclipse AAA model showed some variations in the intensity profile at distances beyond 20 cm from the central axis caused by the different shape ofthe diagonal profile. Some minor differences were also encountered in thecollimator back scatter factors obtained from the output factors.

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Conclusions: Photon beam data (6 and 15 MV) from the Trilogy and Clinac
showed no significant variation. When compared to the same data measured
on the TrueBeam system, some small differences (<2%) were found in the
output factors, mainly for the large field sizes. Differences were found in the
diagonal profile at distances beyond 20 cm and were more noticeable on
the 15 MV. These showed as differences in the final intensity profile from thephoton algorithm at distances beyond 20 cm. These results should only affectvery large field sizes and thus should not have clinical significance.

be near the patient. Parallel plate ionisation chamber and Gafchromics®films
were used for measurements and calibration. A large volume chamber wasused for radioprotection measurements. For the daily measurement a system
to fix the ionisation chamber is provided by the society. It is performed for only
one applicator.
Results: The repetability is within 1% (for 3 applicators). The reproducibility
is within 4 % (depending of the applicator). The daily measurement of thedose rate is within 2 %. Depending on the applicator, HVL, depth dose anddose rate are different. The HVL is between 0.6 and 0.7 mm. The depth of
the 50% isodose is between 4 and 7 mm. The dose rate is between 15 and28 Gy/min. Radiation leakage is inferior to 1 mGy however there is scatteredradiation from the patient, lead apron and gloves are necessaries near thepatient.
Conclusions: The new "Papillon50TM" machine appears to have features totreat different small lesions with safety and security. As there is scatteredradiation, it is necessary for the users to maintain a safety distance or to wear
lead protections.
1473 poster

1471 poster
COMPARISON OF TWO EVALUATION PROGRAMS FOR THE
WINSTON LUTZ TEST
S. Glessmer1 , T. Maass1 , F. Fehlauer1
1
S TRAHLENZENTRUM H AMBURG, Hamburg, Germany
Purpose: According to DIN 6847-5, the position of the radiation isocenterand the diameter of the isocenter sphere of a linear accelerator have to beverified at least once a year. For this purpose, the Winston Lutz test can beutilized. In case of stereotactic treatment, the test should be performed before
each treatment session. The focus of this study is on the comparison of two
different programs utilized for the evaluation of Winston Lutz images.
Materials: For the Winston Lutz test, a metal sphere is inserted into the collimated beam. Its projection is recorded by an electronic portal imaging device(EPID). The test is performed for multiple gantry and / or collimator angles.
The resulting images are exported in TIFF format and analyzed using either
the commercially available program DoseLab Pro (Mobius Medical Systems)
or Winston Lutz Analyzer ("WLA"), a self-written MATLAB based tool. By
using Doselab Pro, the diameter of the collimated circle can be determinedby manually adjusting the radiation field threshold. The diameter of the projection of the metal sphere is determined by adjusting the radiopaque object
threshold. The offset of both circles is calculated in x and y direction as wellas the maximal offset in arbitrary direction. WLA offers the use of the threshold principle as well ("WLA color"). As an alternative method, the edges of thecircles are defined by adjusting the position of two vertical and two horizontal
lines ("WLA circles").
Results: With all evaluation modalities, similar but seldom identical results
could be obtained. However, in both cases the acceptance criterion of a spacial deviation less than 1 mm in the isocentric plane was met. The maximum
deviation between Doselab Pro and WLA results was 0.20 mm ± 0.10 mmin the isocentric plane, which was attained for Doselab Pro and WLA circles;
the maximum deviation between WLA color and WLA circles was 0.24 mm ±0.10 mm.
Conclusions: Deviations between the evaluation modalities can be explained by the difficulty of graphically defining the border of the circles. In
addition to this, the limited spatial resolution of the EPID images in WLA allowes only minimal steps of 0.12 mm in x and y direction in the isocentric
plane. Doselab Pro evidently uses interpolated images. Nevertheless, allevaluation modalities can be successfully utilized for the analysis of Winston
Lutz images.

DOSIMETRIC CHARACTERISATION OF A CARBON FIBRE TABLETOP IN THE KV ENERGY RANGE
E. Spezi1 , P. Downes1 , E. Radu1
1
V ELINDRE C ANCER C ENTRE, Department of Medical Physics, Cardiff,
United Kingdom
Purpose: The purpose of this work was to characterise the attenuation properties of a carbon fibre tabletop in the kV energy range and to evaluate theimpact that this may have in the development of solutions for including concomitant dose from CBCT in treatment planning.
Materials: The iBEAM Evo carbon fibre (CF) couchtop is built as a foam core
sandwiched in carbon fibre layers. The thickness of the CF layers is 2 .20mm for a total of 2.40 mm, with a maximum of 4.5 mm in the indexed frame
area. The dosimetric characterization of the iBEAM couchtop was carried out
in the kV energy range using X-ray beams generated by an Elekta XVI unit
integrated in a Synergy linear accelerator. The dosimetric characterisation of
the CF couchtop was carried out by measuring the dose at the centre of a
Plexiglas cylindrical phantom of 15 cm diameter positioned at the isocentreof the CBCT unit. Measurements were carried out through repeated static
irradiations taken in step of 10 degrees. All measurements were taken withan NE2571 farmer chamber and repeated for the two main kV energies usedclinically at our centre: 120 kV and 100 kV. A Monte Carlo model of the CF
couchtop was also built from a CT scan of the table.
Results: The variation of the kV beam attenuation as a function of the gantry
angle is shown in Figure 1. For both energies data are normalized to the ion
chamber readings at the 0 degree angle irradiation. The beam attenuation
within the central ±10 degree angle is ~10% for 100 kV and 120 kV. The
attenuation gradually increases until it reaches a maximum value of ~19% at
120 degrees. The attenuation for 100 kV is ~2% higher than for 120 kV X-ray
beam. We have also calculated the percentage dose difference between thephantom dose calculated with and without the presence of the CF couchtop.
Differences of up to -15% can be found between the two cases. Furthermore,
the dose difference, although symmetric in the left-right direction, is not uniform in the anterior-posterior direction.

Conclusions: In this work we have dosimetrically characterised a CF couchtop used in kV CBCT. The measurements and the calculations that we presented in this investigation suggest that neglecting the attenuation propertiesof the CF table may lead to an overestimation of the concomitant dose from
CBCT of up to 15%.
1474 poster
DOSIMETRIC IMPACT AFTER AN UPGRADE TO THE MLC SOFTWARE
F. Ribeiro1 , L. Carita1 , M. E. Poli1
1
I NSTITUTO P ORTUGUÊS DE O NCOLOGIA DE L ISBOA F RANCISCO G ENTIL ,EPE, Department of Radiation Oncology, Lisboa, Portugal
Purpose: Nowadays, technology is evolving more rapidly and software upgrades for radiotherapy machines has been done more frequently what leaveus the question which tests are need to be done in order to keep IMRT delivery the same. For treatments using dynamic intensity modulated radiotherapy (IMRT), the adjustment of multileaf collimator (MLC) parameters that
affect both the optimization algorithm and dose distributions, is crucial. In ourcase the MLC parameter that affected IMRT plans after the MLC software
upgrade was the leaf gap offset. The aim of this study is to demonstrate how
a MLC software upgrade can affect dosimetric parameters, consequently affecting beam fluence for IMRT delivery. In order to verify dosimetry changes
after MLC software upgrade, a set of tests were performed which include thetransmission (T) and the dosimetric leaf separation (DLS); MLC reproducibility and stability; and patient specific quality assurance (QA).
Materials: Tests were performed with a Varian 2100 C/D linac operated at 6
MV equipped with a 120 leaf Millenium multileaf collimator with dynamic modeand Varian MLC software vs 7.2. The treatment planning system (TPS) was
Eclipse (vs 7.5). Both film and ion chamber measurements were performed
for static and dynamic MLC (DMLC) fields to quantify the parameters T and
DLS.
Results: The rounded leaf end shape of the MLC design results in an offset
between the radiation field edge (the physical leaf position) and the light field(the geometric leaf position). The leaf position is calibrated to the leaf tip at
the mid-leaf plane. There is an additional offset between the geometric leaf
position and the projected leaf tip position called leaf gap offset. The leaf gap
offset is a parameter set on the machine that influences directly the beam
fluence for IMRT. To find out the best leaf gap offset value is necessary tocheck at least transmission and DLS. It was evaluated that after the MLC
software upgrade the optimum value for the leaf gap offset was 0.5 mm (0.1mm less than before the upgrade). The small difference in this parametercan make a change of 0.2 mm in DLS, and the same transmission factor.
The absolute and relative doses were checked trough the dynamic fields andpatient IMRT plans; the discrepancies were about 2% and gamma analysis
showed 95% agreement for the measured points.
Conclusions: MLC software upgrade does change dosimetric parameters to
the IMRT delivery. After upgrade a change in the leaf gap offset was necessary to adjust dosimetric parameters. Nevertheless, it is important to notethat small change such as 0.1 mm in the leaf gap offset can cause a discrepancy of about 2% in dose for dynamic IMRT plans. So, it is essential toverify dosimetric parameters after a software upgrade in order to get the optimum MLC adjustment that produces the best agreement between TPS andthe beam fluence.

with a calibration certificate from the NPL. Checks were made on output stability and repeatability, time vs dose linearity, timer end error, field uniformity
and relative output factors for each cone with reference to the 5cm diametercone.A QC program was instigated with reference values established duringcommissioning. QC incorporates mechanical checks and output calibration
performed monthly and measurements of HVL, relative output factors for all
applicators, output linearity and field uniformity carried out according to anannual schedule.
Results: Stability of the output was found to be within 5% of the value established during commissioning. Measurement confirmed the HVL of the unit
to be within 6% of the manufacturer’s specification. The relative output factor
was established to be unity (±3% difference from standard 5cm) for 6 applicators. The applicator with the largest diameter (12cm) was removed fromclinical use due to a non uniform dose distribution detected using film. It has
been confirmed that the measured dose is proportional to the exposure time
for the entire working range (099 sec). All parameters measured during QC
checks undertaken over a three year period have been within tolerance.
Conclusions: A very low energy X-ray device used for treatment of various
skin conditions has been successfully calibrated under fixed conditions using a parallel plate ionisation chamber. A QC program has been effectively
introduced and to date performance has been maintained to a satisfactory
level.
1476 poster
EFFECT OF THE TABLE TOP AND IMMOBILIZER ON THE TARGETDOSE IN RADIATION THERAPY
C. Pesznyak12 , D. Sinkó2 , I. Polgár2 , T. Pócza1 , T. Klinkó2 , T. Szalai2 , C.
Weisz2 , P. Zaránd2
B UDAPEST U NIVERSITY OF T ECHNOLOGY AND E CONOMICS , I NSTITUTE
OF N UCLEAR T ECHNIQUES , H UNGARY , Budapest, Hungary
2
U ZSOKI H OSPITAL, Budapest, Hungary

1

Purpose: Several methods have been developed to reduce tumor motions
and patient movements during radiotherapy. Using the different materials inradiotherapy requires an investigation of the effects of these materials on therelevant dose parameters. Equipments and table top should be of low electron density material to avoid modification of dose distribution. The authors
made several measurements to check the effect of table top and body fixationon the delivered dose.
Materials: The authors used for the test measurements several body fixation, such as: CIVCO MedTec Carbon Fibre Bellyboard, Timo Headrest,
Extended Wing Board and three different table top; CIVCO MedTec tennis
racket, carbon fibre for linear accelerator Varian 2100C with two photon energy 6 MV and 18 MV and for cobalt unit Theratron 760C original table top.
For the dosimetric measurements PTW Unidos (PTW, Freiburg) electrometer,
the NE 2571 Farmer chamber and PTW Mini phantom were used. The measurements were evaluated according to the IAEA TRS 398. The treatment
planning was based on CT images.

1475 poster
DOSIMETRY AND QUALITY CONTROL OF A GRENZ RAY THERAPY
UNIT
M. Skikiewicz1 , J. Parry1 , H. Moseley1
1
N INEWELLS H OSPITAL AND M EDICAL S CHOOL, Department of Medical
Physics, Dundee, United Kingdom1472 poster
DOSIMETRIC ASPECTS OF THE X RAYS 50 KV MACHINE
S. Marcié1 , E. Poupon2 , O. Croce3 , J. P. Gérard4
1
C ANCER C ENTER A NTOINE -L ACASSAGNE . U NIVERSITY N ICE S OPHIA A NTIPOLIS, 2nd Radiotherapy Department, Nice, France
2
PAQA, Nice, France
3
U NIVERSITY OF N ICE S OPHIA A NTIPOLIS, Nice, France
4
C ENTRE A NTOINE L ACASSAGNE, Department of Radiotherapy, Nice,
FrancePurpose: A new machine, "Papillon50TM" , is commercialised since 2009 forcontact X-ray therapy. It products low energy X rays, 50 kV. We present dosimetric and radiation protection aspects of this machine.
Materials: The new machine produces 50 kV X rays (50 kV and 2.7 mA).
Features of this machine are an integrated computer, record of the treatment,
safety keys, cooling time, viewing system made of 3 optic fibers to see thelesion. The tube diameter is 1.8 cm. Different kind of applicators are available
with different FSD: for rectum, skin and eyelid. Each applicator is recognized
by a color ring. An articulated arm allows to fix the applicator and to avoid toS 549

Figure 1. Radial plot of iBEAM CF couchtop beam attenuation for 100 kV and
120 kV X-ray beams.

Purpose: The use of very low energy X-rays (Grenz rays) in Radiotherapy
Departments has declined to zero in the UK. However, as Grenz rays are on
the border of Ultraviolet Rays and share some biological properties, their use
has continued in dermatology, particularly in Scandinavia. The Departmentof Dermatology at Ninewells Hospital installed a Grenz ray unit supplied by
Progressus Medica AB, Sweden, in 2007 and asked Radiotherapy Physics tocommission the unit. Although a substantial number of papers on the effects
of very low energy X-rays on various skin conditions are available, there are
few reports on dosimetry and QC aspects. This presentation describes thecommissioning process, the continuing QC program and an assessment of
the long term operation and stability of this unit.
Materials: The Grenz ray unit operates at 10kV and 10mA, producing a beamwith an HVL of 0.035mmAl. Field size is defined by a range of 7 cones withdiameters 1, 2, 3, 5, 7, 9 and 12cm and an FSD of 17cm. Dose delivery iscontrolled solely by exposure time and so the first task was to measure theoutput in Gy/sec for the 5cm diameter applicator. The relevant IPEM Codes ofPractice for determination of absorbed dose for very low energy X-rays were
followed. This required an HVL to be measured and a field ’soft X-ray’ chamber to be cross-calibrated against a secondary standard ’soft X-ray’ chamber

Results: On 6 MV photon energy the attenuation of the carbon fibre table
top is somewhat higher (1.86%) than that of the tennis racket insert (1.24%).
On 18 MV these values were lower (1.03% and 0.38 %, respectively). The
attenuation of the original table top of a Theratron cobalt unit was more than
10% for a PA field. The average attenuation of the immobilizers depends onthe energy the field size and the gantry angle. For PA fields the absorbed
dose is modified by 5% (Co), 3% (6 MV) and 1.5% (18 MV) if immobilizers
are used.
Conclusions: The high strength and low density carbon fibre is an excellent solution for table top and fixation systems of small attenuation. During
the treatment planning the immobilizer devices shall be outlined so that theattenuation of it can be calculated and the effect of the build-up region canbe considered. The patient fixation with CIVCO equipment is very easy andsafety. For the exact radiotherapy treatment, we have to make a QA/QC protocol for handling of table top and different immobilisation device.
1477 poster
EPID BASED MLC QA FOR AN UNFLAT BEAM PROFILE
C. Wessels1 , S. Nill1 , U. Oelfke1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Medical
Physics in Radiation Oncology, Heidelberg, GermanyS 550

QA: OF EQUIPMENT

QA: OF EQUIPMENT

Purpose: Quality assurance using EPIDs with flattened beams is widelyused in clinics and supported by multiple commercial tools. However, more
and more modern linear accelerators are capable of delivering IMRT fields at
higher dose rates. These higher dose rates are mostly achieved by removing
the flattening filter. Therefore, the unique characteristics of the unflattened
beam, e.g. its profile, have to be considered when determining the actualleaf positions, such that the well-known procedures for flattened beam quality
assurance become obsolete.
Materials: We used the integrated amorphous silicon device of a Siemens
Artiste with a detector resolution of 0.04cm. The panel was positioned at a
distance of 160cm from the source. It was irradiated by a 7MV unflattened
beam using a dose rate of 1000MU/min at numerous gantry and collimatorangles. For each evaluated field size one hundred images were acquired
and averaged for further evaluation.The first algorithm investigated follows aprocedure proposed by Siemens for profiles measured in a water tank. The
basic principle is to multiply the profile by a field size dependent scaling factor, empirically determined for square fields. The actual leaf position is thengiven by the 50% value of the scaled profile.In general, for this method, twoissues must be considered: The scaling factors are only known for square
field sizes and the field size must be known in advance. Therefore, in thefirst step our algorithm estimates the field size by calculating the global maximum and minimum of the first derivative. This value is then used to calculate
the individual scaling factor for each leaf pair using a spline fit for the scaling
values provided by Siemens.The second algorithm evaluated uses the basic
approach already known for flattened fields. It calculates the position of thehalf maximum on the profiles extracted from images corrected for gain, deadpixels and offset. Both algorithms were implemented in MatLab.
Results: Both algorithms are capable of accurately determining the leaf positions using an EPID in combination with an unflattened beam. The achieved
accuracy is in the range of 0.5mm independently of the gantry angle, collimator angle and field shape. The second algorithm does not rely on any specificcalculations of fits or derivatives and is therefore faster. The only calculations
necessary are the basic image processing steps prior to the calculation of theleaf positions.
Conclusions: These preliminary results are very promising but still need
to be further verified by comparing the results of the EPID based methodwith measurements in water phantoms or using films. Especially the impact
of noise needs to be evaluated for the case where no image averaging is
performed.
1478 poster
EVALUATION OF PORTAL IMAGE QUALITY USING DEDICATED
PHANTOM
B. Blasiak1 , M. Litoborski1
1
G REATER P OLAND C ANCER C ENTRE, Department of Medical Physics,
Poznan, Poland
Purpose: The Electronic Portal Imaging Devices (EPID) are used for patient positioning verification during radiotherapy treatment. Regular quality
controls of the EPID play essential role in ensuring constant high quality ofacquired images. The aim of the study was to check the consistency of theimage quality for EPID systems installed on different linear accelerators.
Materials: The PTW EPID QC Phantom was used during the study. Eachtime, it was placed on the couch in the isocenter. To cover all test elements ofthe phantom, a field size of 26x26 cm2 was used. The images of the phantom
were performed on 4 Varian linear accelerators using PortalVision Imager
with Image Acquisition System (IAS) versions 2 and 3. Three different quality
acquisition modes were used: Low Dose (4 frames), High Quality (10 frames)
and Integrated Image (10, 50 and 100 MU). Images for two different photon
energies were used (6 and 20 MV). 175 images of the phantom were taken
for all modes, energies and linacs. Quality parameters, such as: linearity,
isotropy, distortion, signal to noise ratio (SNR), and low and high contrast
resolution in one focal point geometry, were detected by different area of thephantom.
Results: The software epidSoft 2.1 provided with the phantom was used foranalyzing the images from the EPID. Evaluation results were checked withthe predefined software limit values. Most of the analyzed parameters, i.e.:
linearity, isotropy, low and high contrast resolution and distortion, did not display significant deviation from the limits. In some cases the linearity values
exceeded the limits. There were significant differences observed for the signal to noise ratio as a function of absorption steps. For the energy of 6MV,
the differences of mean value (expressed in percent) between two different
versions of IAS were 42.63 to 42.69; 42.43 to 43.63; 82.30 to 85.95; 82.78
to 89.91; 82.68 to 90.02 for low dose, high quality and integrated image (10,50 and 100MU) modes, respectively. For the energy of 20MV the differenceswere 23.82 to 24.76; 23.81 to 24.92; 69.85 to 75.64; 72.95 to 76.36; 73.55 to
76.57 for all modes, respectively.
Conclusions: The EPID QA Phantom and conforming software can be used
simply and clearly to ensure the image quality of the EPID. Image quality
met the analysis criteria and did not depend on how the EPID calibration
was performing. when the EPID calibration was performing. The significant
differences for the signal to noise ratio may be caused by the reversal of
portal images. That problem is not about the quality of the image but rather

with reading the original image imported from DICOM files. It was observedthat values of SNR are higher for IAS3 than IAS2, especially for the integrated
image scanning mode, which is used by portal dosimetry.
1479 poster
EVALUATION OF THE FIELD SIZE AND LEAF CALIBRATION USINGAQUILAB MLC 80 LEAF MODULE
A. Esmail1 , F. Coveney1 , P. Rixham1 , S. Weston1 , P. Bourel2
1
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom
2
AQUILAB, Loos les Lille , France
Purpose: With the increase need to deliver advanced treatments such Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc
Therapy (VMAT) there is a greater expectation on the performance for external radiotherapy control systems such as MLC leaf positions. We report
the evaluation of MLC 80 leaf module using Aquilab software compared toconventional radiotherapy film on an ELEKTA Digital Linear Accelerator MLCi
leaf system.
Materials: MLC 80 leaf module is MLC QA analysis based of EPID images.
We report MLC field size accuracy and MLC leaf calibration compared to conventional EDR2 film. In order for Aquilab to use EPID images the IView Panelwas calibrated using a template at 100cm SSD. The calibration template consisted of perspex plate with cross hair marking and tungsten ball bearings
spaced between 20 and 10cm spacing. The EPID image of the template
enabled Aquilab to calculate cross hair centre, rotation and pixel size. We
evaluated 20cm, 10cm and 5cm square fields using Aquilab to analysis EPID
images and compared them to standard film and a Macbeth densitometer.
From this we evaluate the performance of the field size module using for reproducibility and accuracy. Five EPID images were taken for each field size
selection with and without leaf movement between each exposure. Aquilab
analysis software determined average field sizes based on FWHM measurements from eight profiles per field. Standard EDR 2 films were marked at
100cm SSD processed and measured at FWHM for absolute field size comparison. MLC calibration was also evaluated following full MLC major/minor
leaf calibration. MLC calibration module determined each leaf position using EPID images. As with field size, FWHM calculations were made using
each profile to determine each leaf position from the prescribed position foreach leaf. Because of 1mm tolerance margins for each leaf position, we investigated the variation of leaf position based on four different EPID templatecalibrations.
Results: We found the field size module extremely producible and less than
1% positional difference in results from leaf movements between each exposure from Aquilab software. However we also found that there was max
deviation of 1.2mm in the MLC leaf direction when compared to leaf pair 20.
With closer examination we concluded it may be due to variations in minor
leaf positions as calculated profiles positions from the software could not be
moved. As a results our MLCi head underwent a full major/minor leaf calibration and procedure repeated. Results after re-calibration showed extremely
good agreement with measured films with a maximum difference of 0.43mm
in both MLC and Jaw direction for all field sizes. For MLC calibration module,
four calibration template images we taken and a perpendicularity test was
performed. Perpendicularity test allows us to quantify who well our templateis aligned i.e. tilt/rotation. We found that leaf deviation was sensitive to tilt
or rotation from the template calibration. From four template calibrations weachieved variability in results from <1mm to 2.62mm leaf positional error.
Conclusions: Aquilab MLC 80 leaf module was evaluated using images from
EPID. We achieved excellent reproducibly and accuracy in field size results
when compared to standard EDR2 film. We found maximum difference of
0.43mm between Aquilab and film. MLC calibration module was found tosensitive the template calibration resulting in a large variability and results.
1480 poster
FIRST CLINICAL EXPERIENCES WITH RAPIDARC ON UNIQUE™
E. Vanetti de Palma1 , A. Fogliata1 , G. Nicolini1 , A. Clivio1 , L. Cozzi1
O NCOLOGY I NSTITUTE OF S OUTHERN S WITZERLAND, Medical Physics,
Bellinzona, Switzerland
1

Purpose: The first Unique™clinical activity started the 15th of June 2010,
when the first worldwide new Varian low energy linac was installed. The
objective of this work is to present the clinical activities and summarize thestatistics about patient treatments on Unique™, focusing on machine performances, RapidArc capabilities and improved imaging.
Materials: MU and dose-rate linearity checks were performed; in addition
the stability of this magnetron based linac was compared to that of a klystronbased one. Before introducing RapidArc treatments the behavior of the Varian Portal Vision (PV) during rotation was assessed, then the RapidArc commissioning tests were acquired using this EPID. Clinical indications, numberof patients, basic treatment plan characteristics will be presented according
to updated statistics at time of presentation. For RapidArc treatments, pretreatment quality assurance procedures and results will be discussed. Treat-ment modalities and IGRT will be outlined.
Results: MU and dose-rate linearity checks and magnetron performance investigations produced results absolutely compatible with high energy linacs.
Machine quality assurance will also be presented to show the linac stability
especially for what is concerning the RapidArc delivery on a low energy machine. Since its clinical introduction, at time of submission (six month of activity), 208 patients have been on treatment, mainly head and neck, breast andbrain. Of those patients 56 received RapidArc treatment (25 head and neck,
15 breast, 5 thorax, 4 brain with metastasis, 3 pelvis and 4 other), 10 IMRT
(all breast patients, 2 of them with also respiratory gating) and 142 3DCRT(among them 20 with respiratory gating). IMRT was at the beginning used
only for breast cases including nodal region irradiation; for this pathology wequickly moved to RapidArc treatments. RapidArc is today used for all headand neck patients on Unique™, using mainly two arcs.The Unique™capabilityof using the 2D-2D matching of two orthogonal MV images allows a more precise patient positioning. Pre-treatment QA is performed with PV integrated
images converted to dose with the GLAaS method on all IMRT fields and
RapidArc arcs.
Conclusions: Technical tests on Unique™performances were satisfactory,
especially with respect to RapidArc delivery. Unique™was smoothly introduced in clinical practice in our institute.
1481 poster

S 551

imperative the inexistence of rotations or translations between the coordinate
system of the lasers and the generated by the TC’s ring.On the other hand,using the fiduciary markers of its localization box, the Brainlab’s stereotactic
system is able to transform the coordinates of an arbitrary TC image into thecoordinates in the system where the box is aligned with the TC’s ring, with
its origin in the center of the box.In that way, positioning the localization box
using the lasers of the TC, the Brainlab’s system has to calculate and identity
rotation and a known translation. Any deviation from that behavior is due
to a defective alignment of the lasers or to an incorrect performance of thestereotactic system.
Materials: A set of TC images of the Brainlab’s localization box has been
performed in such a way that its centering markings follow the lasers system.
The coordinates of 21 randomly chosen points have been established in theoriginal and in the localized TC images. Using these data the rotation andtranslation bounding both coordinate systems has been calculated.
Results: Using the nomenclature of the figure, the isometry that maps thelasers system into the localized system involves a translation of (0.80±0.53,
0.09±0.53, 1.09±0.52) mm followed by a α=0.093±◦ 0.023◦ rotation about
X axis, a β =0.291◦ ±0.023◦ rotation about Y axis and a γ =0.469◦ ±0.019◦
rotation about Z axis. Uncertainties of 0.1 mm in the coordinates of the points
and 0.5 mm in the localization of the box’s center using the lasers systemhave been considered for the calculus of the uncertainties of the parametersin the transformations.

GEFAQA.NET - AN AUTOMATED DOSE PROFILE EVALUATIONTOOL IN THE MNEME FRAMEWORK
S. L. Krogh1 , J. Westberg1 , C. Hansen1 , H. L. Riis1 , C. Brink12
1

O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
DenmarkU NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark2

Purpose: Periodical dose profile QA is done by evaluating key values of themeasured profile and subjective comparison with manually stored reference
profiles. This procedure is time consuming and error prone due to the amountof human interaction and subjective evaluation. If a new set of reference profiles are generated for a given linac, the process of introducing these in QA
procedures is also time consuming and prone for error because the meansof archiving is without automated control.A tool is needed that automates
the reference storage and searching, as well as quantifying the conformanceof measured profiles to reference profiles. The reference search should becompletely automatic so that as a measured profile is loaded, the reference
profile, corresponding in radiation type, field size, etc. to the measured, isretrieved instantly. User management should be implemented as well so thate.g. only authorized users are able to edit reference data. Furthermore theability to choose from several different sets of reference profiles (commissioning and treatment planning system model) is desired.
Materials: The in-house developed Mneme database for QA data is used
for storing and retrieving both reference profiles and measured profiles forhistorical analyses. For quantifying the conformance of measured profiles
to reference profiles, 2D gamma evaluation is performed. Furthermore thekey characteristics previously used for profile quality evaluation (symmetry,flatness, etc.) were implemented to supplement the gamma evaluation, and tomaintain consistency with previous analyses.The software was developed in
the Microsoft .NET 2.0 framework using C# and Microsoft SQL Server 2005.
Results: An application in the Mneme software suite was developed. The
quality of the profile evaluation was optimized by automating the search forreference data and quantifying profile conformance with gamma evaluation.
Using gamma evaluation for profile conformance guarantees a homogeneous
evaluation unaffected by the individual physicist performing the procedure.
Conclusions: The GEfAQA.Net application has been in clinical use for six
months at the time of writing. It has introduced a fundamental change in
the QA procedures concerning dose profile evaluation. The time spent on
the dose profile QA procedures in general was diminished substantially. The
time reduction was mainly obtained in making the process of finding the correct reference profile obsolete, which in turn entailed the removal of a sourceof human error. Also the user satisfaction of the QA procedure in general
has improved. Introducing GEfAQA.Net has increased the homogeneity ofthe evaluation of measured data and quantified the criteria which these mustsatisfy.
1482 poster
INTERCOMPARISON BETWEEN BRAINLAB’S STEREOTACTICSYSTEM AND THE LOCALIZATION SYSTEM BASED ON THE
LASERS OF A TC
F. Del Moral1 , L. Pereira1 , E. Meilan1 , J. Vazquez1 , D. Medal1 , M. Salgado1
1
H OSPITAL DO M EIXOEIRO, Medical Physics Department, Vigo (Pontevedra), Spain

Purpose: Opaque markers are commonly used for isocenter localization inexternal radiotherapy. An alternative procedure is the application of a mark to
the TC of the patient in the point where the lasers intersect. In this context it isIf the Brainlab’s stereotactic system is considered free from errors and it isassumed a perfect positioning of the box by the operator, these transformations involve a misalignment of the lasers. On the other hand, assuming thelasers system free from errors, the transformations represent the scale of theerrors due to the stereotactic system. In general, the most realistic situation
is when every error source is considered.
Conclusions: Observed differences between the positioning by lasers andthe use of a stereotactic system are within the accepted tolerances. It has
been developed a method for intercomparison between both systems thatcan be helpful during commissioning.
1483 poster
MNEME – A QA APPLICATION FRAMEWORK IN MODERN RADIATION THERAPY
J. Westberg1 , S. L. Krogh1 , C. Brink12
1

O DENSE U NIVERSITY H OSPITAL, Laboratory of Radiation Physics, Odense,
DenmarkU NIVERSITY OF S OUTHERN D ENMARK, Institute of Clinical Research,
Odense, Denmark2

Purpose: In the modern radiotherapy department QA plays an important roleto ensure optimal treatment delivery and minimal machine downtime. It is
important that the QA procedures provide information about every aspect of
the clinic from dose planning to end of treatment. This includes data aggregation from a number of systems used in the clinic. Treatment verification
systems currently available provide only QA on a patient or fraction basis,and little or no support of automatic data aggregation from external systems.
To maintain a higher level of QA this should be extended to population based
analysis and aggregate information from multiple systems to identify systematic errors and deviations in the clinic that are difficult to identify in individual
treatments.In this study a QA application framework for technical QA in radiotherapy treatment was designed. It contains data from multiple measuring systems, equipment information, and important parameters used in the
QA procedures. This will increase the overall QA quality by organizing data
across all linacs in the clinic, and obtain correlation between measurements
and changes in parameters related to the treatments.

S 552

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QA: OF EQUIPMENT

Materials: Using the Mosaiq (Elekta) verification system as the origin of allclinical data, a new associated database is implemented to store QA data that
Mosaiq currently does not handle. A .NET 2.0 library implements the mostcommon classes used to model a radiotherapy department including readers
to interpret data and files from various measuring systems. The framework
defines a common interface to all new QA applications such that analysis are
consistently performed, and data is stored in the database to enable integration with other measurements or analysis of various types across the clinic.
Results: The new database contains the phantoms, detectors, measuring
equipment and the linacs. These entities contain references to calibration
constants and other important QA parameters. The system allows authorizedusage only and logs who submitted, modified, or approved data. All data ispreserved as only virtual deletion is allowed. Last but not least all patient
dosimetry measurements have references to the patients and the treatment
fields in the Mosaiq database. The system can read and store data from MC2(PTW), Pinnacle3 (Philips), XVI (Elekta) and Mosaiq. All Mneme data areaccessible for analysis using e.g. C#, Excel, or Matlab.
Conclusions: The system has been in clinical use for a year focusing on
gamma analysis of dose profiles, patient positioning and dosimetry. It has
had a positive impact on the QA by organizing and relating QA information
across the clinic. All parameters are registered and approved before use, andall measurements contain information about approval status. This increases
the consistency and reliability of the measurements and makes it possible toperform time dependence analyses.

the junction was formed by the MLC alone or a combination of the MLC andthe Y-jaws. Film measurements showed deviations from the planned dose.
When the junction was made by the MLC alone a systematic underdose wasobserved which amounted to 15% (+/- 9% 2SD) less than the calculated doseby the TPS. The amount of underdose varied depending on the day and linac.
When the junction was formed by the MLC and the Y-jaws a more homogeneous dose was achieved at the junction with a 10% underdose (+/- 4% 2SD)
with respect to the calculated dose by the TPS.Gamma evaluation (3%, 3mm)
at the three planes showed the systematic underdose with respect to the TPS.

Figure 1. Average profile along the field junction (MLC abutment) at the coronal plane showing the underdose with respect to the calculated dose by the
TPS (left). Gamma evaluation (3%, 3mm) of the dose at the coronal planeshowing the underdose at the photon field junction (MLC abutment) (right).
Profiles on the left were taken along the arrow line on the right figure.
Conclusions: Predicted overdose by the TPS at the junction of three nondivergent abutting fields found no correspondence with the delivered dose.
Film measurements at the axial, coronal and sagittal planes revealed a systematic underdose. Whereas for junctions formed by the MLC and the Y-jaws
a rather homogeneous dose is achieved, that is not the case for junctions
made exclusively by the MLC where the amount of underdose is 15% (+/- 9%2SD) with respect to the predicted dose by the TPS. Unwanted underdose
for these junctions can be avoided by shifting the matchline for some of thefractions.

1484 poster
NEW METHOD TO RELATE THE MEASUREMENTS MADE BY THE
STARTRACK® DEVICE WITH THE VARIATIONS OF R50
J. M. D. L. Vega Fernandez1 2 , S. Ruiz Arrebola1 , D. Guirado Llorente1 , M.
Vilches1 , A. M. Lallena3
1
H OSPITAL U NIVERSITARIO S AN C ECILIO, Granada, Spain
2
F UNDACIÓN I NVESTIGACIÓN B IOSANITARIA A NDALUCÍA
Granada, Spain
3
U NIVERSIDAD DE G RANADA, Granada, SpainO RIENTAL,

Purpose: In the last decade, different equipments, which include phantoms
and ionization chambers simultaneously in an unique device, have been developed to facilitate routine QA measurements. However, it is not simple tolink the results of the measurements performed with these devices with theparameters that characterize the operation of an accelerator. The work presented here shows how relate the variations in the value of R50 [1], thatcharacterizes the electron beam spectra, with the measurements made withthe device StarTrack® of Iba Dosimetry® .
Materials: StarTrack® is a matrix of 453 ionization chambers arranged inside
a water equivalent phantom. It permits to measure profiles, normalized tothe average of the 9 central chamber measurements, with a resolution of 5
mm in the vertical and horizontal profiles and 9 mm in the diagonals ones.
In addition, an electron phantom, which has 1 cm equivalent water thick andeight circular sectors with different thicknesses, can be placed on top of thematrix chambers (panel A of the figure); so one chamber is located undereach circular sector. In this way, relative ionization deep dose curves (PDI),
normalized to the average of the 9 central chambers measurements, can beobtained. Specifically, a total of eight measurents at eight points are obtained(labelled P1, P2 ... P8), to estimate the stability of the electron beam energy spectra.To relate the variability in the electron spectra with the variation
recorded with StarTrack® , we varied the current of the BM (IBM), displacing
the selection window over the intrinsic spectra [2]. For each IBM we measured the PDIST with StarTrack® and the PDIBP with a Blue Phantom andan EFD diode of Iba Dosimetry® . We did these measurements for the six
electron energies of a Siemens Artiste® accelerator (6, 9, 12, 15, 18 and 21MeV)).Finally we made a complete analysis of the relationship between thevalues obtained at the eight points, previously mentioned, from PDIST andtheir quotients with the values of R50 obtained from PDIBP, trying to findsome mathematical expression that relate the variations between them.
Results: In all the cases for each energy of operation a mathematical relation
was obtained between R50 and some ratios of two values Pi (i= 1,2...,8). In
panel B of the figure, we show the variation of the ratio P1/P3 and R50 for the
6 MV mode. In this case, an exponential function was fitted: P1/P3 = Aexp(KR50)+B, where A, B and K are constants. The vertical line represents thevalue of R50 for the usual operation IBM of the accelerator.The exponential
dependence tends to change towards a linear dependence as the energy
increases. This happens because the variation in the measurements at theeight points is relatively smaller for high energy and this shows up throughthe ratios.

S 553

1486 poster
QUALITY ASSURANCE ON RECEPTION OF NEW RADIOCHROMICFILM BOXES
J. Lopez-Tarjuelo1 , N. de Marco-Blancas1 , J. D. Quirós-Higueras1 , X. J.
Conclusions: In this work we describe a new method to relate the measurement record with a device designed for the routine control of the energy
stability, StarTrack® , with the actual variation of R50. In this way it is easier to estimate the importance of the variations observed in the daily control and make an appropriate decision in the context of a quality control program.This method could be generalized to similar devices.References:[1] Andreo P, Burns DT, Hohfeld K et al. Absorbed dose determination in externalbeam radiotherapy: An international code of practice for dosimetry based onstandards of absorbed dose to water. International Atomic Energy Agency,
Technical Reports Series 398. Vienna, 2001.[2] de la Vega JM, Guirado D,
Vilches M, Perdices JI, Lallena AM. Obtaining the intrinsic electron spectrumof linear accelerators using the relation between the current of the bending
magnet and the absorbed dose in water. Rad and Onc. 2008;86:109-113.
1485 poster
PHOTON JUNCTION FIELDS FOR BREAST IRRADIATION: IS THE
DOSE DELIVERED AS PLANNED?
M. Palacios1 , L. Murrer1
1
MAASTRO C LINIC, Heerlen, Netherlands
Purpose: Treatment planning systems (TPS) usually predict either an overdose or underdose at the junction of two abutting photon fields. A quality
assurance (QA) program at the clinic aims among others at checking thedosimetric integrity of the equipment and delivering a highly homogeneous
dose at junctions, for instance by means of an IMRT fence test. The purposeof this study is to test whether the predicted dose by the treatment planningsystem (TPS) at the junction of three non-divergent abutting photon fields forbreast irradiation agrees with the delivered dose.
Materials: Plans were made with XiO, CMS (version 4.51) TPS. The technique used consisted of three non-divergent abutting fields: an AP beam forsupraclavicular irradiation and two parallel-opposed tangential breast beams.
Two types of junctions were tested: fields abutting exclusively with the MLC(Siemens Optifocus, 82 leafs) and fields abutting with the MLC and the Yjaws. Kodak EDR2 films were exposed in a solid-water phantom at axial,
coronal and sagittal planes. The junction of the three fields was measured
several times at different days and at all linacs (Siemens Oncor) available inour clinic.
Results: Our TPS showed a consistent overdose (107 113%) at the junction of the three non-divergent abutting photon fields, independently whether

Juan-Senabre1 , A. Santos Serra1 , S. Calzada-Feliu1
C ONSORCIO H OSPITALARIO P ROVINCIAL DE C ASTELLÓN, Servicio deRadiofísica y Protección Radiológica, Castelló de la Plana, Spain

1

Purpose: Radiochromic film is widely employed to verify IMRT treatments. A
common procedure used in order to optimize film preparation is to calibrate
one sheet per box. Doing this makes it necessary to assume that mean
pixel value remains constant over all the sheets in the box. In addition, each
sheet needs to be sufficiently uniform. Quality assurance (QA) testing of
new received boxes has been developed to ensure compliance with theserequirements.
Materials: In this study, for QA testing 2 boxes of radiochromic film
Gafchromic EBT-2 (ISP, NJ, USA) were used. A sample of ten sheets fromeach box was read with an EPSON V700 Perfection Photo (Seiko Epson
Corp., Nagano, Japan) digitizer (size DIN-A4). Average pixel value and uniformity calculations were performed using in-house programs made with MATLAB (Mathworks, MA, USA). Non-uniformity was evaluated using isoresponse
curves.
Results: All the samples taken from the first box presented with a uniform
narrow central area only, so that response increased unacceptably whenmoving to the borders. As it became clear to us that these films could not
be used for dosimetry, we reported this information and sent the sample tothe manufacturer, who then diligently replaced the box.The raw non-uniformity
assessed with the second box, without correcting for lamp effects, was within±2% over much of each film. The ratio between standard deviation of mean
pixel value and mean pixel value was 1.3%. The mean pixel value of the central region of each sheet varied up to a 1.9% if the sheet was digitized flipped.
Ratio between standard deviation of mean pixel value and mean pixel value
was reduced to 0.8% when some sheets were taken flipped.

Conclusions: QA avoids dosimetric errors due to detector deficiencies.
Feedback from users helps the vendor to improve his manufacturing process.
It is supposed that better results could be achieved during verification if mean
pixel value is kept as constant as possible, and this could be done by flipping some of the films after reading and before digitizing again and irradiatingthem. It would be very valuable to the user if manufacturer published his
specifications. The user could then determine his acceptance tolerances for
non-uniformity, for example ±3% over the 90% of the film surface.
1487 poster
QUALITY CONTROL OF THE CLINAC GEOMETRICAL PARAMETERS USING THE PORTAL VISION SYSTEM.
F. Candela1 , A. Cámara1 , D. Martínez Rodríguez1 , M. Melchor1
1
H OSPITAL U NIVERSITARIO DE LA R IBERA, Department of Medical Physics
and Radiation Safety, Alzira, Spain
Purpose: In a linear accelerator (LINAC) some checks of the geometric parameters must be done regularly, and usually they are done with radiographic
or radiochromic films.It is suggested here to do these controls by using theportal vision system, as a method to achieve an easier set up when doing
them, reducing this way the time spent, and avoiding the use of films. Asan additional advantage, an error in these controls result can lead to detect
errors in portal vision detection, so geometric controls on that device are increased.This method is used as a regular test, and if the threshold is reached,an additional check with films is carried on, to detect if the error is producedby the LINAC or the Portal Vision system.
Materials: In the Radiation Therapy department there are 2 LINACs (VARIAN 2100C y 2100C/D) with amorphous silicon Portal Vision.Matherials usedhave been, for the tradicional method of the controls (radiographic film), XOMAT V films, KODAK X-OMAT 2000 developer and EPSON 10000XL scanner.And for both methods the QA UTOPIA analysis software (see references) ,isocentric control phantom, and an opaque for radioactivity small round bar
were used.Methods for carrying on each test are the following:
1. Collimator isocenter. Star with narrow beam, conformed with jaws,
which rotates with the collimator. Using the Portal Vision gets to easier
set up.
2. Table’s isocenter. Star with radioopaque stick placed at the isocenteron the table. The beam is irradiated each n degrees and the resultant image is similar to the one of the film. (instead of the film, theradioopaque marker is placed on the table).
3. Gantry isocenter. Star with radioopaque stick placed at the isocenteron the table with 45 angle referring to GT axis. A Portal Image is acquired at each stablished gantry angle, and they are added, processed
and analysed with the Utopia software.
4. Light-radiation field coincidence. Isocenter control phantom. Jaws are
positioned so Light remains over on the radiation opaque marks of thephantom, and image is acquired and the field of light and radiation arechecked, analysing the difference with the utopia software.
5. MLC Position control. An adquisition with a known MLC shape is performed, and it is blended in the Portal Vision computer with a reference
image sent from the Radiotherapy planning system, just like in clinicalcase.
References:
1. REF(1) Valoraciantitativa de tratamientos en radioterapia externa conla funcindice gamma. Presentacil software UTOPIA , Dorado Rodrez,
M.Pilar. et al - Revista de Fca Mca 2007; 8(1): 29-32

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QA: OF SOFTWAREQA: OF SOFTWARE

Conclusions: DoradaQA appears as a consistent and useful software to perform routine MLC and jaw position QA based on EPID imaging in an ONCOR
linac, after a comparative study with ImageJ software using EPID images andfilms.References:
1. SJK Baker et al., "Use of an amorphous silicon electronic portal imaging device for multileaf collimator quality control and calibration", Phys.
Med. Biol. 50 (2005) 1377-92

Results: All controls described above have been validated with the classicalfilm method, obtaining equivalent results. In the figure the irradiation collimator star with both methods is shown.
Conclusions: This system has many advantages, because it saves set up
time and avoids the use of expendable materials or the necessity of buying
additional QA devices. Besides, the result is obtained in a very short time,
without spending time in developing films.As an additional advantage, there
is a greater geometric control on the Portal Vision, because errors in its geometry will result in errors in these tests. In these cases, a posterior analysis
with the film would discard a linac error, revealing an error in the Portal Vision.
1488 poster
VALIDATING AN EPID-BASED SOFTWARE (DORADAQA) FOR MLC
AND JAW POSITION PREDICTION IN AN ONCOR LINAC
A. Domínguez Folgueras1 , C. Pinza Molina1 , A. Ramirez1 , S. Fernández
Cerezo1 , M. D. Morillas Pérez1 , S. García Gómez1
1
H OSPITAL U NIVERSITARIO N UESTRA S EÑORA DE C ANDELARIA, Department of Medical Physics and Radiation Safety, Santa Cruz de Tenerife, Spain
Purpose: IMRT treatments call for a quantitative and reliable MLC QA. The
use of EPID has arisen as a good alternative since images can be acquired,analyzed and stored quickly. No specific QA software is commercially available for MLC analysis in an ONCOR (Siemens) linac.The aim of this work
is to present the validation data of the DoradaQA software developed in our
department (based on MatLab 2010b), in order to evaluate the accuracy andprecision of the MLC and jaws positions using EPID images, and to implement this software in routine QA.
Materials: The ONCOR linac is equipped with 82 leaves MLC (OptiFocus). A
6MV beam was used.An OptiVue 1000ST EPID with an active imaging area of
41 x 41cm2 and pixel size of 0.4mm was used. The SSD was 115cm. All automatic corrections were maintained.XV-Omat radiographic films were used at
the isocenter under 15mm of plastic water. Films were scanned at 400dpi witha Vidar Scan.The EPID images and films were acquired with 40MU without
MLC reset.Field sizes studies were 5cmx5cm, 10cmx10cm and 20cmx20cm.
Several images were acquired in order to evaluate the reproducibility.Different
asymmetric jaw positions (Y1, Y2) were analyzed: -5, 0, 10 and 15cm.Majorand minor MLC offset, as defined in [1] were studied for X1 and X2 bank at theprescribed positions: -10, -5, 0, 5, 10 and 15cm.EPID images were analyzed
using DoradaQA and with ImageJ software, also used for film analysis. Results of DoradaQA were compared to ImageJ data (EPID images and films),
using SPSS statistics software.
Results: For square fields of all sizes, the results obtained for EPID images
with DoradaQA and ImageJ show a very good agreement, with differences ofless than 0.04mm, and a reproducibility of 0.05%.DoradaQA data for asymmetric jaw positions show a good agreement with film analysis, with a meandifference of 0.4mm (SD=0.3mm).Major offset differences measured in EPID
images with ImageJ and DoradaQA software for X1 and X2 banks are under 0.03mm, maximum minor offset difference for X1 is 0.05mm and 0.04 for
X2, for all field sixes and MLC positions.Results of major and minor offset
differences analyzed using ImageJ (film) and DoradaQA (EPID) are shownin Table 1. Major offset data show maximum differences of -1.3mm (X1=10cm) and 0.84mm (X2=5cm), whereas the mean differences are 0.5mm(SD=0.4mm) and 0.4mm (SD=0.3mm) respectively. Mean minor offset differences are smaller than 0.3mm (SD=0.3mm) for both MLC banks.

2. L Parent et al., "Evaluation of two methods of predicting MLC leaf positions using EPID measurements", Med. Phys. 33:3174-82 (2005)

QA: of software
1489 poster
ACHIEVING GTV CONSISTENCY IN A DEPARTMENT - USE OF A
CONTOUR COMPARISON TOOL
N. Whilde1 , S. Mukherjee2 , G. Andrade2 , C. Macmillan2 , C. Halle2
1
N ORTHAMPTON G ENERAL H OSPITAL NHS T RUST, Department of Medical
Physics and Radiation Safety, Northampton, United Kingdom
2
N ORTHAMPTON G ENERAL H OSPITAL NHS T RUST, Oncology Department,
Northampton, United Kingdom
Purpose: With the move to 3D conformal planning and IMRT of more treatment sites, volumes are increasingly being used to plan radiotherapy as opposed to field based virtual simulation. There is a great deal of publisheddata on the differences in the definition of Gross Tumour Volumes (GTV) between clinicians; both within the department and inter-departmentally. Thisis cited as a major source of variation in patients’ treatment. Using a newly
developed software tool to compare rectal cancer GTVs defined by different
clinical oncologists; similarity scores were generated and reviewed by a multidisciplinary team, which included a radiologist. The expected result was moreconsistent definition of GTVs for patients with rectal cancer.
Materials: The software application ImSimQA is designed to aid physicists
to commission image registration and other radiotherapy applications. It includes an optional application to quantify the difference between a pair of RT
structures sets withcontours on a single CT scan. Three clinical oncologists
working at Northampton General Hospital defined a GTV on each of a number of CT planning scans from patients with confirmed rectal cancer. The CT
scans and structure sets were then imported into ImSimQA . The GTVs werecompared using the specialist application and scored. The scoring system
is based on a distance to agreement measurement on each CT slice. The
results were then reviewed by a multi-disciplinary team, including all 3 clinicaloncologists and a radiologist. Following the review; a new set of GTV contours were generated on different CT scans by the same clinical oncologists.
These were again compared using the contour analysis tool.
Results: The GTVs were more consistent between clinical oncologists following the review of scores in the contour comparison software. This is shown
quantitatively using the scoring system.
Conclusions: The ImSimQA contour analysis software tool has many applications. The quantitative analysis of contours very much aids in the comparisonof target volumes. The same process is being rolled out for other treatmentsites; and it will be used as a training tool for all staff groups being trainedin GTV and OAR definition. It would also be a powerful tool in the QA ofradiotherapy trials.
1490 poster
AN EVALUATION OF IMSIMQA AS A TOOL FOR COMMISSIONING
4DCT
S. McGOWAN1 , N. Whilde1
1
N ORTHAMPTON G ENERAL H OSPITAL NHS T RUST, Department of Medical
Physics and Radiation Safety, Northampton, United Kingdom
Purpose: 4D CT scanning is used increasingly in radiotherapy departments
to track the motion of tumours in relation to the respiratory cycle of the patient.

4D CT monitors the breathing cycle of the patient and can either: a) acquire
CT images at a certain point in the breathing cycle, based on a particularphase of the breathing cycle or the amplitude; or b) acquire CT images over
the whole breathing cycle and then sort by phase or amplitude. This CT
data is then used to either generate a PTV that encompasses the motion of
the GTV; or to gate the radiotherapy treatment. The aim of this paper is tocommission the representation of the 4D CT dataset in 2 commercial planningsystems using the software tool ImSimQA .
Materials: The software application ImSimQA is designed to aid physicists
to commission image registration and other radiotherapy applications. It
includes an optional 4D application to simulate respiratory gated images.
ImSimQA has the facility to generate virtual phantoms which can be modified
and exported into treatment planning systems as DICOM images. The 4D option allows for translations, rotations and scaling of objects within the phantom
to create a series of 4D DICOM CT images; and because the objects are being transformed by known amounts in each phase, the reproduction of thistransformation in the treatment planning system (TPS) can be checked. The
Maximum Intensity Projection (MIP) and Average Image (AI) generated in the
CT scanner software can also be checked accurately. A phantom was generated consisting of a body, a lung, three ribs and a tumour object. A rangeof phased image sets were generated with the objects either being scaled
and/or translated. The 4D datasets were exported to both the AcQSim virtual
simulation package, and the Eclipse TPS. They were also exported to thePhilips Brilliance Big Bore CT scanner.
Results: A range of 4D CT datasets, from simple 2 phase scans with a single object translation to non-sinusoidal multiphase 4D CT datasets, were imported into both TPSs. In all cases, the 4D CT dataset was generated correctly; and the movie loop correctly predicted the position of the objects atthe correct part of the phased scan. The above 4D CT datasets were also
exported to the CT workstation. The MIP and AI scans were generated as
expected from the ImSimQA data.
Conclusions: Eclipse and AcQSim can accurately reproduce and represent
image data required for planning gated radiotherapy treatment. Tumor Loc
can accurately generate MIP and AI images for use within the TPSs. Using virtually generated CT data onecan test the TPSs more thoroughly thanphysical phantoms and to a finer degree of accuracy than true phantoms as
the movements are digitally defined and have an almost infinite degree of
freedom.
1491 poster
MULTIMODAL DOCUMENT- AND IMAGE MANAGEMENT IN RADIOTHERAPY. HOW TO HANDLE DOCUMENTS AND CLINICAL IMAGESIN A GENUINE DIGITAL ENVIRONMENT
F. Heinemann1 , F. Röhner1 , M. Schmucker1 , K. Henne1 , G. Bruggmoser1 ,F. Momm1 , A. L. Grosu1 , M. Hall1 , S. Kirrmann1
1
U NIVERSITÄTSKLINIK F REIBURG, Klinik für Strahlentherapie und Radioonkologie, Freiburg, Germany
Purpose: For two years the Clinic of Radiotherapy at the University Hospital Freiburg has switched to a complete digital environment; that means all
information (images like x-rays, CT, MRI, patient documents, treatment dataand scans) are hold digital. In this context questions and problems appeared
which have to be considered and solved.The approval of the treatment protocol, the correct assignment and uniqueness of images and documents has to
be integrated in a digital workflow. External findings, images and documents
have to be scanned. The delivery of information to external institutions, hospital or physicians has to be done well managed. Also the concepts of digital
storage, backups and data access must be considered.
Materials: The Clinic of Radiotherapy at the University Hospital Freiburg
has installed an operative unit (Clinical and Administrative Informatics - CAI)
which is responsible for all relevant clinical-organisational and administrative
processes on the base of information technology (IT). The main task of thecomplete IT supply has been supplemented by duties like archive management, quality management (QM), diagnose related groups (DRGs), data protection, medicine controlling, tumor documentation, material logistics and supervision of patient- and ward-management. Together with other professions
in the hospital this group has designed a workflow which gives us the ability
to answer the open questions and to solve the existing problems. Beside ofthis we achieved a smooth workflow with excellent performance and growing
income. Invaluable instruments for this are our new commercial department
system, the PACS, cooperation with their manufacturers and a number of inhouse software developments.Furthermore we have integrated all relevant
processes into our quality management system (QM), so that they are traceable. Moreover sophisticated concepts for digital storage, backup and access
control ensure data integrity, data security and permanent availability.
Results: All patient related information (images and documents) will either behold digital or replaced by analogical digital processes. Their assignment andintegrity is checked by continuous digital control algorithms and random manual inspections. Having QM conform process management and documentation ensure traceability.In addition our authorities agreed to run this workflow
officially.Some document qualities like letters to inform patients about their
upcoming appointments (approximately 5000 per annum) are not longer produced manually; they are generated and printed out full automated using dataof the department database directly.

S 555

Conclusions: In a genuine digital environment there occurred a lot of questions and issues concerning document und image handling, in parts difficultand complex.Using a sophisticated workflow, the proper software- and hardware environment will highly support our hospital to operate a genuine digital
environment without annoying and obstructive problems.The increasing number of national and international visitors in our clinic and their positive feedbacks underlines our trigger function for other big hospitals to organize theirdata handling in the same effective way.
1492 poster
ON DIFFERENCES BETWEEN DIFFERENT VERSIONS OF A TPS
P. Carrasco de Fez1 , N. Jornet1 , A. Latorre Musoll1 , T. Eudaldo1 , R.
Agustí1 , M. Ribas Morales1
1
H OSPITAL DE LA S ANTA C REU I S ANT PAU, Servei de Radiofísica iRadioprotecció, Barcelona, Spain
Purpose: New versions of TPS software are supposed to agree with experimental data at least as well as previous ones as they are developed to fix bugs
or to improve calculations. As new versions are implemented while working
in clinical routine, the user may have little time to verify them resulting in a
reduction of the QC tests. The aim of this work was to show large differencesin very specific items between two software versions (Eclipse v8.0 and v8.9)that could have not been detected with a reduced set of tests
Materials: During the commissioning of a Varian Clinac 2100 CD an extensive set of absolute dose measurements, beam profiles (BP) and depth dose
curves (PDDs) were measured for 6 and 15 MV beams in order to have reference values for testing the TPSMU verification tests were performed forvarious SSD, various MLC shapes, all physical wedges and all dynamical
wedges for 10 different rectangular fields. In addition 12 asymmetric al fields
were also tested for open fields at SSD=100 cmPDDs and BP comparisonswere made using the Beam Analysis module in Eclipse in terms of some parameters (For BP: left and right distance to agreement (DTA) for the 80%,
50% and 20% dose. For PDDs: depth difference of maximum and 50% doseand dose difference at 100 mm and 200 mm)For Eclipse version 8.9 Varian recommends to measure new additional data (PDDs at 80 & 120 cm forphysical wedges, a dose-rate table for the same fields and longitudinal profiles for various fields). After measuring these data, they were added to the
TPS and calculations were run again for v8.9. According to the vendor information the tuning procedure required in previous versions to fit the MU for all
the Enhanced Dynamic Wedges (EDW) and all field sizes was not to be done
anymoreResults: A marked increase in the disagreement in v8.9 was observed between calculations and measurements in three cases
1. EDW in 6 MV photons: constant difference about +2% with the exception of the 45 EDW and the 10 EDW. After talking to a Varian specialist,
the EDW parameters were tuned to get acceptable results for all fieldsizes (old procedure). After this tuning most discrepancies were between -1% and +1% with an only a value of about 2% for the 10X(2+8)
asymmetric field in the EDW45
2. PDDs were better except for the position of the 50% dose for the larger
field sizes for the open fields and the depth of dose maximum for the 30
and the 60 physical wedges for some field sizes. Varian reproduced
our results for the wedges and observed that when the new recommended data were removed, the behaviour improved
3. The distance between calculations and measurements for the 80%
dose at the right side of BP for the 60 physical wedge: there wasa large systematic difference of up to 4 mm. Both for open fields
and wedge fields, the differences are larger as the field size increases
and the profile is deeper. This problem has been analysed by Varian
engineers and "recognized as a known issue" adding that "a new codein future version will be used, which fixes this issue"
Conclusions: Tests on new versions of a TPS have to be as extensive as theinitial commissioning ones as very specific items can vary largely and would
be not detected by reduced tests. The vendor should clearly tell the customer
which versions include major changes in advance and the customer shouldschedule a suitable period of time for testing without any routine calculationinterference
1493 poster
QUANTIFICATION OF DIFFERENCES BETWEEN VERSION 4.40
AND 4.60 OF THE SUPERPOSITION ALGORITHMS OF XIO (CMS)
F. Del Moral1 , L. Pereira1 , E. Meilan1 , B. Andrade1 , M. Salgado1
1
H OSPITAL DO M EIXOEIRO, Medical Physics Department, Vigo (Pontevedra), Spain
Purpose: Quantify the differences in dose calculus in XiO (CMS) by its superposition algorithm after an update from the version 4.40 to the 4.60.

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R ADIATION P ROTECTIONR ADIATION P ROTECTION

Materials: It has been used a homemade application that, using as data
the DICOM-RTDose calculated before and after the update, calculates histograms with the quantities shown in the figure. D1,i and D2,i are the dosesat point i for the 4.60 and 4.40 algorithms, and D0 is the prescription dose.
Moreover, if nj is the number of points with dose D1in the 4.40 treatment
planning and DDk with k=1..nj are the values of the differences between the
two algorithms, it has been calculated the mean value <DD>j, the standard
deviation ST(<DD>j) and the mean square <DD2 >j1/2 of the differences.
Results: The table shows the change in UM for every beam when a prostate
IMRT treatment planning calculated with version 4.40 of the superposition
algorithm is open (and automatically recalculated) using version 4.60. Figures
show the result of the defined metrics and their uncertainties when the original
UM in version 4.40 are reintroduced in version 4.60. Prescription dose is 7800
cGy and analysis is only performed in points belonging to the PTV.

Conclusions: It is confirmed that software updates in the treatment planningsystem, even for the same company, have to be performed following a strict
acceptance protocol that researches the differences.

Radiation Protection
1494 poster
COMPARISON OF NEUTRON CONTRIBUTION TO PERIPHERALDOSES IN PATIENTS UNDER 3D-CRT, IMRT AND RAPIDARC
TREATMENTS
M. Paiusco1 , E. Cagni1 , S. Filice2 , C. Ghetti2 , M. T. Romero Exposito3 , J.
A. Terrón4 , B. Sanchez-Nieto5 , F. Sanchez-Doblado3 4
1
A RCISPEDALE S. M ARIA N UOVA, Reggio Emilia, Italy
2
A Z . O SPEDALIERA PARMA, Parma , Italy
3
U NIVERSIDAD DE S EVILLA, Fisiología Médica y Biofísica, Seville, Spain
4
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiofisica, Sevilla, Spain
5
P ONTIFICIA U- DAD C ATOLICA DE C HILE, Santiago, Chile
Purpose: Nowadays, new techniques such as IMRT and RapidArc are being introduced in clinical routine. Therefore, it is mandatory to determine
the relevant parameters allowing for comparison with conformal radiotherapy for optimal treatment selection. The purpose of the present work is tobring the attention on photoneutrons contribution to the peripheral dose received by the patient as one the parameters to be considered in plan comparison/optimization.
Materials: Four different treatments (head and neck, prostate, rectum andgynecologic) were delivered to a phantom in a 18 MV Varian Clinac 2100
C/D and a 15 MV Varian DHX 2100 linac. 3D-CRT and IMRT treatments
were planned in the first linac and 3D-CRT and RapidArc treatments in thesecond one. During the planning process, the goal was to cover PTV with the
95 % isodose line. Equivalent doses and risks associated to neutrons were
estimated using the procedure presented in [1, 2] and based on the readingsof a digital detector [3].
Results: The main difference between the techniques regardingneutron production, is the number of Monitor Uinits (MUs) and energy used. Both, RapidArc and IMRT, require an increase of MUs with respect to conformal treatments. Thus, we found higher doses in these treatments, especially in IMRT.
As an example, for a rectum treatment at the 15 MV linac, equivalent doseto the lungs shows a 1.4 and 2.3-fold rise for RapidArc and IMRT treatments,
respectively. For all pathologies, IMRT treatment at the 18 MV linac, shows
the highest risk of acquiring a second cancer due to neutrons (rectum casein fig. 1).

S 557

dose measured inside the phantom to establish a procedure of patient neutron dose calculation. [1] Sanchez-Doblado F, Domingo C, G F et al. Neutron component in peripheral dose of patients under radiotherapy. Radioter
Oncol 2010;96:S475. [2] G F, Iglesias A, Shez-Doblado F. A new active
method for in-room neutron measurements in radiotherapy. Phys Med Biol
2010;55:1025-1039.
1497 poster
NEUTRON DOSE IN PELVIC RADIOTHERAPY TREATMENT LOCATION.
J. A. Terrón1 , M. T. Romero Exposito2 , R. Barquero3 , C. Domingo4 , M.
J. Garcia-Fuste4 , K. Amgarou4 , F. Gomez5 , J. I. Lagares6 , F. SanchezDoblado21
1
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiofisica, Sevilla, Spain
2
U NIVERSIDAD DE S EVILLA, Fisiología Médica y Biofísica, Seville, Spain
3
H OSPITAL U NIVERSITARIO DE VALLADOLID, Valladolid, Spain
4
U NIVERSITAT AUTÒNOMA DE B ARCELONA, Cerdanyola, Spain
5
U NIVERSIDADE DE S ANTIAGO DE C OMPOSTELA, Santiago de Compostela,
Spain
6
CIEMAT, Madrid, Spain

Conclusions: Different techniques have been compared just in terms of neutron contribution to second cancer induction, with IMRT showing the highest
risk. Due to a minor number of MUs in conformal treatments, they show thelowest risk. This new parameter should be also considered in the selectionof the optimal treatment for the patient. [1] Sanchez-Doblado F, Domingo C,
Gomez F et al. Neutron component in peripheral dose of patients under radiotherapy. Radioter Oncol 2010;96:S475. [2] Romero-Exposito M T, Terron
J A, Barquero R et al. Experimental model for determination of neutron peripheral dose in patients undergoing high energy photon beam radiotherapy.
Radioter Oncol 2010;96:S473. [3] Gomez F, Iglesias A, Sanchez-Doblado
F. A new active method for in-room neutron measurements in radiotherapy.
Phys Med Biol 2010;55:1025-1039.
1495 poster
INDIVIDUALIZED POSITIONING FOR BREAST RADIOTHERAPY: A
COMPREHENSIVE APPROACH FOR OAR PROTECTION
Z. Kahán1 , Z. Varga1 , A. Cserháti1 , K. Hideghéty1 , K. Boda2 , L. Thurzo1
1
A LBERT S ZENT-G YÖRGYI U NIV.M ED.S CH ., Department of Radiotherapy
Oncology, Szeged, Hungary
2
A LBERT S ZENT-G YÖRGYI U NIV.M ED.S CH ., Department of Medical
Informatics, Szeged, Hungary
Purpose: The radiation dose and technique, patient characteristics and systemic therapy have been found to influence the development of radiogenic
sequelae1,2,3 . We set out to extend our previous work on the preferable
mode of individual positioning for breast radiotherapy based on comprehensive OAR protection1,2,3 .
Materials: Conformal radiotherapy plans in patients requiring right or left
breast irradiation were developed for both the prone and the supine position. The advantages of the prone over the supine position in terms of
the lower radiation exposure (mean dose and V25Gy) of the myocardium
and the left anterior descendent coronary artery (LAD), and the relative reduction in the mean lung dose (MLD) to the ipsilateral lung ([MLDsupineMLDprone]/MLDsupine) in the prone position were analysed in relation to theanatomical features of the patients (volume of the irradiated breast [PTV],
BMI, waist and hip size).
Results: The data on 60 patients requiring left and on 26 requiring rightbreast irradiation were analysed. In the overall population, the radiation doseto the myocardium or the LAD did not differ with the position, whereas that tothe ipsilateral lung was dramatically lower in the prone than in the supine position (p<0.0001). The radiation exposure of the myocardium and the LAD,
however, was significantly reduced in the prone position, in patients withlarger breast, BMI, waist or hip sizes (n=60) (Table). Likewise, the relative
reduction in the MLD to the ipsilateral lung in the prone position correlated
significantly with increasing BMI (n=81) (Table). Since there was a strong correlation between the BMI and the waist and hip sizes, the PTV and the BMI
were included in multivariate analyses. Only the BMI remained significant asa factor predicting the benefit of prone positioning, and no interaction was
found between the BMI and the PTV (Table). ROC curve analyses demonstrated that patients with BMI>26.3 kg/m2 benefit most from prone positioning as regards myocardium and LAD exposure, and patients with a BMI>26.1
kg/m2 benefit most as regards the dose to the ipsilateral lung.
Conclusions: BMI is a sensitive and specific measure for selection between
the prone and the supine position if optimal OAR protection is aimed at during
breast radiotherapy.
1 Kaht al. Int J Radiat Oncol Biol Phys 2007; 68:673-681.
2 Varga et al. Int J Radiat Oncol Biol Phys 2009; 75:94-100.
3 Varga et al. Int J Radiat Oncol Biol Phys 2010.
Univariate and multiple linear regression analyses of the radiation dose to therisk organs and the patient-related features

1496 poster
NEUTRON CONTAMINATION MEASUREMENTS AT ITHEMBA LABS
PROTONTHERAPY FACILITY.
F. Sanchez-Doblado12 , M. T. Romero Exposito1 , J. A. Terrón2 , J. J.
Nieto-Camero3 , A. Korf3 , M. Loubser3
1
U NIVERSIDAD DE S EVILLA, Fisiología Médica y Biofísica, Seville, Spain
2
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiofisica, Sevilla, Spain
3
I T HEMBA LABS, Medical Radiation, Somerset West, South Africa
Purpose: Proton and ion beams provide the possibility of highly conformal
dose distributions with the potential of dose escalation. In addition, the integral dose delivered with protons and ions is significantly lower than withphoton beams, which would imply a lower risk for radiation-induced cancers
when using protons. However, the risk associated with undesired neutron
production is not well understood. The purpose of this work is to study thisproduction in order to estimate the dose received by the patient in a specificfacility, no previously evaluated.
Materials: A set of experiments has been performed to characterize the neutron production in the medical proton facility at iThemba Labs in South Africa.
The same procedure already applied to conventional photon radiotherapy [1]has been followed. We used a digital detector [2] to measure the neutron
dose at a location inside the room (near room wall, figure 1) in different irradiations of an anthropomorphic phantom to study dependences on beamenergy and target volume size and depth.

Results: The main dependence neutron production at location in figure 1 ison the number of monitor units of the treatment. We found a lineal dependence, as in photon radiotherapy. For the different irradiations, there wereno significant differences among the events per MU at digital detector. The
deviation of these values was about 10 %. Moreover, these values are of thesame range of values at conventional radiotherapy, similar to 15 MV Varianlinacs or higher energy linacs. However, these results present the uncertainty
associated to the lack of knowledge about delivered dose by fast neutrons,since digital detector is mainly sensitive to thermal neutrons and a calibration
at those high neutron energies has not been performed.
Conclusions: We used a digital detector to characterize the neutron production at a proton facility under different irradiation conditions. A larger
production of thermal neutrons regarding photon radiotherapy has not beenfound. This measurement will be correlated to neutron equivalent organ

Purpose: Neutron peripheral dose is a new issue of interest. Recent publications dealing with second cancer induction and the new ICRP recommendations make it even of more interest. A project was developed to evaluate patient neutron dose and a model was designed to know this dose fromthe readings of a digital detector [1]. Nevertheless, the generalisation of themodel is difficult as there are many different parameters (treatment rooms,
linac manufacturer, patient size, treatment location). Some of them were considered in the model design but when real measurements are made it is noteasy to compare the different treatments. In order to simplify this comparison, the treatments were grouped according to the site of treatment. Oneof the groups selected were the pelvic treatment. The aim of this work is
to show that there is no significant difference in neutron dose to the organsof interest outside the region of treatment when rectum, urinary bladder andgynaecological pathologies are treated.
Materials: Equivalent doses to organs were evaluated from the digital detector readings using the model previously developed [2]. More than one
thousand patients have been evaluated in 40 different facilities. Treatments
were delivered using 15, 18 and 23 MV photons from 40 different linacs fromthree different manufacturers (Siemens, Elekta and Varian). Patient treatments were measured at least in one session.
Results: The comparison of the treatments selected (rectum, urinary bladderand gynaecological region) by means of the equivalent dose at 15 points
of interest (brain, thyroid, lung, oesophagus, breast, stomach, liver, bladder,colon, ovaries, testes , skin, red marrow, bone survace, remainder) showsthat there is no significant difference among these doses. The deviation is
below 15 %.

Conclusions: The results show that to allow an easy intercomparison between different linacs these treatments could be grouped together. Other
pathologies from a similar site, such as prostate treatments, have not begrouped due to the high incidence and to the particularity of its treatment
as usually is highly conformed and then is of special interest to be comparedby itself.[1] Sanchez-Doblado F, Domingo C, Gomez F et al. Neutron component in peripheral dose of patients under radiotherapy. Radioter Oncol

S 558R ADIATION TECHNOLOGISTSR ADIATION P ROTECTION

2010;96:S475. [2] Romero-Exposito M T, Terron J A, Barquero R et al. Experimental model for determination of neutron peripheral dose in patients undergoing high energy photon beam radiotherapy. Radioter Oncol 2010;96:S473.
1498 poster
NEUTRON FLUENCE DISTRIBUTION STUDY IN A PROTON THERAPY FACILITY BUNKER
J. I. Lagares1 , P. Arce2 , F. Sansaloni1 , J. A. Terrón3 , M. R. Expósito4 , J. J.
Nieto-Camero5 , A. Korf5 , M. Loubser5 , F. Sanchez-Doblado6 3
1
CIEMAT, Medical Applications Unit, Madrid, Spain
2
CIEMAT, Basic Research, Madrid, Spain
3
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Radiotherapy Department,
Sevilla, Spain
4
U NIVERSIDAD DE S EVILLA, Fisiología Médica y Biofísica, Seville, Spain
5
I T HEMBA LABS, Medical Radiation Department, Somerset West, South
Africa6
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Fisiología Médica yBiofísica, Sevilla, Spain
Purpose: Neutron radiation contamination is an undesirable radiation in radiotherapy treatment, which increases the probability to produce second cancers. It has a special relevance in proton therapy, because the probability
to generate neutrons is much higher than in other radiotherapy modalities.
The aim of this work is to determinate the neutron fluence distribution in the
bunker room to find an appropriate place for an active neutron detector basedon a digital memory readout, which can be used to estimate the peripheral
neutron dose on a patient [1]. The digital device is sensible to the thermal
neutrons and has to be situated in a place with small flux gradient.
Materials: A real bunker and a beam line were simulated by Monte Carlousing the GAMOS/GEANT4 code[2]. A pelvic treatment was used as a reference case and it was applied to a polyethylene phantom (NORMA)[1]. The
target volume was defined as cylinder with 3 cm of diameter and 3 cm long.
Proton beam had an initial energy of 201.36 MeV and it was modulated usinga passive beam scatter; a brass collimator was used to set the beam diameter. Four neutron tracks maps were built using 1x1x100 cm3 voxels (100 cm
in the vertical dimension), splitting the energy in four intervals (in MeV):[0,1E6] (Thermal neutrons), [1E-6,0.1], [0.1,20] and [20,200]. In each voxel it was
accumulated the lengths of the paths travelled by neutrons. The number ofprotons used in the simulations was 2E6.
Results: The neutron track maps indicate that the thermal neutron distribution is uniform in the bunker room, but it is possible to observe an exponential
decrease along the bunker maze. Nevertheless, it is possible to observe two
hot spots for thermal neutrons. One of them corresponds to the NORMA
phantom and the other one to a multilayer Faraday cup in the room contiguous to the treatment room. On other hand, the fast neutrons from 0.1 MeV to
200 MeV show an exponential decrease with the distance from the beam line
(Fig 1.).

1499 poster
PERIPHERAL GAMMA DOSE AND THERMAL NEUTRON FLUENCIES EVALUATION FOR IMRT ON ADULT, TEEN AND CHILD
F. Sansaloni1 , J. I. Lagares2 , J. Muñiz2 , M. R. Expósito3 , J. A. Terrón4 , L.
Núñez5 , R. Barquero6 , F. Sanchez-Doblado7
1
CIEMAT, Medical Applications Unit, Madrid, Spain
2
CIEMAT, Madrid, Spain
3
U NIVERSIDAD DE S EVILLA, Seville, Spain
4
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Sevilla, Spain
5
H OSPITAL U NIVERSITARIO P UERTA DE H IERRO, Majadahonda - Madrid,
Spain
6
H OSPITAL U NIVERSITARIO DE VALLADOLID, Valladolid, Spain
7
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Sevilla, Spain
Purpose: Neutron production in heavy metal components from LINAC structures is present in radiotherapy treatments with energies above 8 MeV. This
neutron contamination is produced mainly in the gantry parts as flattening filters, collimators or multi-leaf collimators and is of special importance in treatments like IMRT where a larger number of monitors are used. In order toreduce the risk of developing a secondary cancer it is important to have agood knowledge not only of photon dose but as well the dose due to othercomponents such as neutrons. Measuring neutron fluencies received in different organs is the first step to estimate dose delivered at them. In this workneutron fluence at different points for three type of patients, adult, teen andchild has been evaluated [1].
Materials: Two standard treatments were delivered to the phantoms in two
different locations, head and abdomen, using a 15 MV photon beam froma Siemens Primus Linac. A 10 x 10 cm2 field size was used at 8 gantry
angles (0,45, 90, 135, 180, 225, 270, and 315), each of them with 1125
monitor units (MU), delivering a total of 9000 MU in each location. The TLD
pair method consists in the combination of neutron sensitive TLD-600 withinsensitive TLD-700 to separate the gamma and the neutron component.
This is the most common TL procedure employed for the dosimetry of mixed
fields. The TLD pairs were placed in various spots distributed along the whole
NORMA phantoms. Neutron dose at organs of interest would be estimatedfrom neutron dose at these points by means of a model that is being developed elsewhere.
Results: Thermal neutron fluencies at different positions, for abdomen andhead treatment, are shown in table I. The pair method fails at the isocenteras the gamma component is dominant and then a correct neutron component
separation becomes not reliable. For this reason some points near isocenter
were not measured. The gamma dose is higher at teen and child phantoms
than at adult phantom on most of the points. Due to their smaller size thedistance from the isocenter is smaller as well and then a higher dose is found.
The gamma doses are distributed between 8 mSv and 2 Sv. The thermal
neutron fluencies obtained are distributed between 0.2108 n/cm2 and 14.2108
n/cm2 .

PROTONTHERAPY FACILITY
C. Domingo1 , M. J. Garcia-Fuste1 , K. Amgarou1 , F. Sanchez-Doblado23 , J.
Nieto-Camero4
U NIVERSITAT AUTÒNOMA DE B ARCELONA, Department of Physics,
Cerdanyola, Spain
2
U NIVERSIDAD S EVILLA - FACULDAD M EDICINA, Sevilla, Spain
3
H OSPITAL U NIVERSITARIO V IRGEN M ACARENA, Sevilla, Spain
4
I T HEMBA LABS, Medical Radiation Group, Somerset West, South Africa

1

Purpose: Proton beams originated in high energy hadron accelerators leadto neutron production when protons interact with elements present in the
beam line. In addition, when these protons beams are used for protontherapy, their interaction with the patient also leads to neutron production, mainly
due to interactions with C, O and N. This represents a source of unwanted
radiation, which may increase the risk of developing second cancers. The
NEUTOR project is in development in order to assess the corresponding risk
factors for patients under treatment.
Materials: Neutron spectra were measured by means of the active UAB Bonner Sphere Spectrometer [1] at two points inside the treatment room of the
iThemba labs (Cape Town, Southafrica) protontherapy facility, with an anthropomorphic polyethylene phantom to simulate the effect of the patient. Point A
is located in the beam line direction, downstream, 2.33 m after the isocenterand point B is located at the same place that the digital NEUTOR measuring device, at 3.4 m from the isocenter, in a direction at ~60 with respect tothe beam line. Irradiations took place with 200 MeV primary protons, with aphantom irradiated volume of 10 cm diameter and 10 cm depth.
Results: Figure 1 shows the spectra in terms of lethargy found at both measurement points. No significant differences appear from one to the other,as expected from previous simulation results. A neutron high energy peak
(1.69% in fluence, 4.47% in ambient equivalent dose for point A; 1.26% and3.23% respectively for point B) appears at about 100 MeV, accounting for theneutron direct production. A prominent evaporation peak appears at about
1-2 MeV, and thermal and epithermal neutrons are present due to primary
neutrons interacting with the room air, materials and walls. Fast neutrons
lead to the highest contribution to dose (around 85%).

S 559

from the treatment head it is likely that dose rates measured outside of thetreatment vault will be altered.This study aims to quantify the differences in instantaneous and cumulative dose rates measured inside and outside a linac
bunker for flattened and unflattened beams. Data are presented for measurements made under standard conditions and during delivery of clinically
relevant intensity modulated (IMRT) fields.
Materials: A 6MV Elekta Precise linear accelerator has been commissioned
to operate both with and without the flattening filter in place. The beams havebeen energy matched on the central axis by matching beam quality parameters (TPR20/10, D10). Standard field sizes between 2x2cm and 40x40cm
were delivered to a 30x30x20cm solid water phantom in the beam and instantaneous dose rates were measured at points outside the bunker using
a calibrated partially compensated G-M tube. Cumulative doses from IMRT
delivery have been measured with TLD-100 chips.
Results: For a 20x20cm field (GA=180) with the solid water phantom, dose
rate on the roof directly above isocentre for the flattened beam (60µSvh-1 )was slightly reduced for the unflattened beam (57µSvh-1 ), similar reductions were found at the maze entrance (GA=90, 3µSvh-1 to 2µSvh-1 ) andthe control area (GA=-90, 1.5µSvh-1 to background levels). For a 40x40cm
beam with no phantom dose rate was reduced on the roof (150µSvh-1 to
125µSvh-1 ), at maze entrance (30µSvh-1 to 19µSvh-1 ), and in the control
area (5µSvh-1 to background levels). Results for IMRT delivery will be presented.
Conclusions: Radiations levels both inside and outside of the treatment
bunker are lower for filter free delivery compared to flattened beams for thesame beam quality. For a machine operating using unflattened beams, this
could allow for savings in costs for shielding materials as well as contributing
lower doses to the patient and staff.

Radiation technologists
1502 poster
ACADEMIC STATUS OF RADIATION THERAPY TECHNOLOGISTSIN INDIA
G. Singh Wadhawan1 , P. NEGI1 , N. DATTA1
1

R AJIV G ANDHI C ANCER I NSTITUTE & R ESEARCH C ENTRE, Radiation
Oncology, Rohini, Delhi, India
Purpose: To promote high quality education to meet the need for basic training and continuing professional development in radiotherapy and oncology.To
promote multidisciplinary education in oncology with the objective of standardising knowledge and clinical practice, whilst recognising the diversity ofradiation oncology practice in different parts of the world.Courses have beendeveloped to reflect the core curricula and new developments in radiation
oncology and the faculties are drawn from experts in the area.
Materials: RTTs operate simple and complex equipment at different radiotherapy centres India
Teletherapy:
1. Co-60 telecobalt units : 293
2. Cs-137 telecaesium units : nil

Conclusions: The results show that thermal neutron detector will show asimilar response anywhere in the treatment room, except near the bunker
access trough the labyrinth and near the patient. To avoid a high fast neutron
flux, it is convenient to place the digital detector at least two meters far fromthe beam line.
1. Sanchez Shez-Doblado, F, Domingo, C, G, F et al. On line neutron
dose evaluation in patients under radiotherapy. In:Dssel O, schlegelWC, editors. WC 2009, IFMBE Proccedings 25/I, Berlin: Springer.
2009;259-261.
2. P. Arce, P. Rato, M. Canadas and J.I. Lagares, "GAMOS: a GEANT4based easy and flexible framework for nuclear medicine applications",
IEEE NSS/ MIC 2008 Conf. Record pp 316268, 2008

Conclusions: Values obtained for the global dosimetric quantities are of thesame order than those obtained in conventional radiotherapy treatment rooms[2]. Protontherapy treatment planning should, then, take into consideration
the risk of radioinduced cancers due to peripheral neutron doses in a similar
form than in conventional radiotherapy treatments.
Acknowledgements: The authors are indebted to the Spanish Nuclear Safety
Board (CSN) for financial support.
References:
Conclusions: As it was expected, the gamma measured doses are larger
for child and teen phantoms due to the smaller distance from the isocenter.
The thermal neutron fluencies show the same behavior, but not in all points.
Nevertheless the latter will be confirmed in future works.
1. Shez-Doblado, F, Domingo, C, G, F et al. On line neutron dose evaluation in patients under radiotherapy. In:Dssel O, schlegel WC, editors.
WC 2009, IFMBE Proccedings 25/I, Berlin: Springer. 2009;259-261.

1500 poster
PRELIMINARY RESULTS ON NEUTRON SPECTROMETRY AT THE
TREATMENT ROOM OF THE ITHEMBA LABS (SOUTHAFRICA)

3. Gamma Knife units : 08
4. Accelerators : 173
5. Tomotherapy : 02
6. CyberKnife : 02
Brachytherapy:

1. M. Bakali (2001), Ph.D. Thesis, Univ. Auta de Barcelona.

1. HDR units : 166

2. C. Domingo et al. (2010), Radiat. Measurements, 45, 1391-1397.

2. LDR : 25
3. Manual (Intracavitary Brachytherapy) : 97

1501 poster
RADIATION SAFETY SURVEY OF A FILTER FREE ELEKTA LINEAR
ACCELERATOR
J. Phillips1 , L. George1 , M. Ramtohul1 , J. Cashmore1
1

H ALL -E DWARDS R ADIOTHERAPY R ESEARCH G ROUP, Q UEEN E LIZABETH
H OSPITAL, Birmingham, United Kingdom

Purpose: Medical accelerators utilising a flattening filter free design can offer
significant advantages over those operating in a conventional ’flattened’ mode(e.g. increased dose rate and lower leakage radiation). Due to changes inthe beam spectrum, beam profile, and levels of scatter radiation originating

4. Manual (Interstitial Brachytherapy) : 34
5. Sr-90 Ophthalmic Applicators : 20
6. Ru-106 for Ophthalmic Applications : 02
7. I-125 seeds for Ophthalmic Applications : 04
8. I-125 seeds for Prostate Implant Applications : 01
Results: Develop standards for the Quality Assurance of radiation oncology,
to improve the standards of cancer treatment by establishing radiation oncology as a clinical specialty integrated with other cancer treatment modalities.

S 560R ADIATION TECHNOLOGISTSR ADIATION TECHNOLOGISTS

1. to promote the professional profile of RTTs.
2. to facilitate the development of continuing education.
3. the exchange of knowledge between RTTs across the Globe in order
to raise the standard of care to patients.
ARTTI members have been active in trying to ensure that RTTs are accepted
as equal members of the treatment team.
Conclusions:
1. Academic content
2. Clinical Education
3. Core competencies
4. Professional role
5. Assessment
6. Scope of Practice and levels of Responsibility for new graduates andsenior RTTs
7. Qualification and recognition mechanism
Promote international exchange of scientific information on radiotherapy &oncology and related fields of science such as radiophysics and radiobiology.
ARTTI is trying to Establish relationships and cooperation with international,
regional and national societies and bodies in the field of radiation oncology.

mandible was used to restrict lateral positioning uncertainties and the headrotation within the mask.The positions of 4 radio-opaque markers mounted
on the mask surface were determined relatively to bony structures based on
two orthogonal planar images to measure the degrees of freedom of the patients head within the mask. ConeBeam-CT studies were used to evaluate
the magnitude of rotational and translationalaccuracy of patient setup. . The
reproducibility of patient set-up was evaluated for the first three fractions andthereafter once a week until the prescribed dose was achieved.
Results: For all translationas the systematic error of patient set-up was foundto be less than 1 mm which reduced to less than 0.5 mm if additional thermoplastic pelles were used. The necessary margin (setup and internal margin) was calculated to be 2.8 mm in cranio-caudal (CC) direction, 2.5 mm inanterio-posterior (AP) direction and 2.2 mm in right-left direction. If additional
thermoplastic pelles were used these results decreased to 1.5 mm (CC), 1.9
mm (AP) and 2.2 mm (RL).
Conclusions: The achievable accuracy of the mask system with respect topatient setup is comparable to other stereotactic mask systems. Additional
thermoplastic pelles enable to minimize the uncertainties for daily patient
setup and in particular for patients without teeth.

S 561

Purpose: External Accelerated Partial Breast Irradiation (APBI) is a new
method in the breast conserving treatment of women with breast cancer. BothESTRO and ASTRO provided in- and exclusion criteria to use APBI in daily
practice. In our department we are preparing ourselves to start with APBI.
One of the most important prerequisites of external APBI is that the position
variation of the patient is taken into account when delivering a high dose to
the Lumpectomy Cavity (LC). Therefore we are in the process of developing a
position verification method and also define a representative margin for APBI.
Materials: In 9 patients who were eligible for external whole breast irradiation
the surgeon had placed several titanium clips in the LC during the operation
procedure. Since the clips are not visible on the portal images, also three gold
markers were stitched to the wall of the LC. In order to define a representative margin around the LC we analysed the inter- and intra fraction position
variability. By analysing the portal images of the oblique treatment fields weare able to define a 3D patient shift. Furthermore, we analysed the effect of
the window/level settings of the DRR on the match results by changing thesettings.
Results: In one of the nine patients radiation therapy was not appropriate
and for two patients a booster was not suitable, both according to the nationalguidelines. What strikes the most is that there are several drawbacks in theprocedure. We found:1. that the correct detection of the gold markers in the
DRR is highly dependent on the window/level setting that is used, see figure
B and C.2. differences in the marker configuration on the DRR compared tothe portal images, probably due to anatomical changes in the LC, see figure
A and B.3. differences in the day to day marker configuration, this was most
likely caused by rotation of the treated area. We investigated the position
variation of the patient, and to evaluate the influence of the earlier mentioned
drawbacks, we also analysed the variation in the matching procedure. See
the table.

1505 poster
HOW TO SUCCESSFULLY IMPLEMENT A DEDICATED RADIOTHERAPY MRI SCANNER IN A RADIOTHERAPY DEPARTMENT
P. Toft-Jensen1 , A. Kahlen1 , H. Johannesen2 , R. H. Hansen2 , C. F.
Behrens1
1
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Oncology,
Herlev, Denmark2
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Radiology,
Herlev, Denmark

1503 poster
AN INVESTIGATION INTO THE BREAST BOOST TECHNIQUE
AND DELIVERY FOLLOWING WHOLE BREAST IRRADIATION IN
EUROPE
L. Kennedy1 , M. Broderick1 , M. Coffey1
1
T RINITY C ENTRE FOR H EALTH S CIENCES, Discipline of Radiation Therapy,
Dublin 8, Ireland Republic ofPurpose: A breast boost dose is an additional dose given to the area of the
primary tumour after radiotherapy to the breast. It is agreed that the boost
dose is beneficial to patients but published studies highlight different factors
which should influence the selection of a boost technique. The purpose ofthis study was to investigate the implementation of the breast boost techniquefollowing whole breast irradiation in Europe.
Materials: Oncologists and radiation therapists working in Europe completed
an online questionnaire about the selection criteria for prescribing breast
boost techniques following whole breast irradiation.
Results: 52 participants responded to the questionnaire, corresponding toa response rate of 3.2%. 51 (98.1%) of participants advocated the use of abreast boost dose to certain groups of patients following whole breast irradiation. Although there was variation in the patients selection criteria it was
not vastly so, pre-menopausal women under the age of 50, tumours of a highstage and grade, margin status and lymphovascular invasion were the mostcommon factors that were used to advocate a patients for a boost dose. Electron and photon boosts were the most common techniques used (67.3% and44.2% respectively).
Conclusions: The delivery of a breast boost dose is not dependent on one
sole factor but on many factors. Mainly oncologists were in agreement on
the factors that influence the boost selection which suggests that they arefollowing guidelines based on evidence based practice. However there is still
variation present in clinical practice.
1504 poster
EVALUATION OF THE REPRODUCIBILITY OF PATIENT SETUP FOR
A DOUBLE-MASK SYSTEM USING ADDITIONAL THERMOPLASTICPELLES FOR PRECISION RADIOTHERAPY
A. Homayuni1 , D. Georg1 , K. Dieckmann1 , M. Stock1 , R. Pötter1 , A.
1

Osztavics
M EDICAL U NIVERSITY V IENNA, Department of Radiotherapy, Vienna,
Austria1

Purpose: In this study the reproducibility of patient setup was evaluated fora thermoplastic mask system (HeadSTEP (Elekta) combined with a component to support upper jaws (BiteSTEP)). Furthermore, a modified mask using
additional thermoplastic pelles was compared to the standard mask.
Materials: For 21 patients, which were treated at the Department of Radiotherapy of the Vienna General Hospital within the course of clinical routine,
two types of individually adapted mask systems were tested. Either a standard mask combined with an upper jaw supporting device was used or amask with additional thermoplastic pelles at the forehead, the nose or the

Purpose: The aim of this work is to describe a method for implementing a
MRI scanner for radiation therapy (RT) purposes in a department where thestaff has only limited knowledge of MRI.
Materials: An open Philips HFO Panorama 1 Tesla MRI scanner with RT options was installed at the RT department at Herlev Hospital, Denmark next
to the department’s 2 CT scanners. The RTTs already working with the CT
scanners, import of images, and palliative treatment planning were to handle
this new modality. To facilitate the implementation a nine month cooperationagreement was made with the MRI Centre at the hospital i.e. 5 days a week
one qualified radiographer from the MRI centre helped and trained 3 RTTs.
The scanner was used 3 hours daily for diagnostic purposes and 3 hours for
RT purposes. An MRI radiologist and an MRI physicist were available whenever needed e.g. for supporting the RTTs and the oncologist in choosing the
optimal sequences. The radiographers designed all protocols in cooperation
with the radiologist and the physicist. The sequences were optimized to enable target volume delineation based on as few sequences as possible. The
RT departments’ technical workshop assisted throughout the whole implementation making adjustments to the existing fixation equipment in order tomake it MRI-compatible.
Results: At present (after 18 months) 517 patients (426 in 2010) have beenscanned in total, and nearly all patient groups in which MRI is beneficiary fortarget volume delineation are both MRI and CT scanned (fig. 1). The CT and
MRI images are fused prior to delineation. This is possible as the patientsare both CT and MRI scanned in the treatment position. All protocols are
optimized to use as few sequences as possible while enabling proper target
delineation.Due to the cooperation with the MRI Centre, a larger number ofpatients were MRI scanned each day. This ensured that the RTTs learned
faster how to handle the MRI scanner. At present 6 out of 9 RTTs are fully
trained (fig. 1), and at this time no more training has been planed. A project
has been initiated to enable MRI scanning of all patients with curative c. cervix
with a Vienna applicator before interstitial brachytherapy. Several research
projects involving oncologists, radiologists, physicists and RTTs are currently
in progress. Today our department is a reference centre for Phillips Panorama
HFO 1T - RT option.

Conclusions: On theoretical grounds an off-line protocol is not suitable forexternal APBI, since the patient receives only 10 fractions. Therefore online position verification seems necessary to treat the LC adequately. The
gold marker procedure can be implemented in a standard clinical practice.
The results reveal that the window and level settings are of great importanceto define the daily patient shift. Further research is needed to determine a
representative margin.

Conclusions: A key feature in our approach to a successful implementationof the MRI scanner was the cooperation with the MRI centre. This included
the availability of support from a dedicated MRI physicist and radiologist andthe daily support by a qualified MRI radiographer. The easy accessibility
to the department’s technical workshop expertise was of great importance.
Further, it was important that the MRI scanner is placed in the vicinity of theCT scanners, as it is the same personnel that operate both the MRI scannerand the CT scanner including import and fusion of the images.
1506 poster
POSITION VERIFICATION PROCEDURE IN ACCELERATED PARTIAL BREAST IRRADIATION
J. Kuipers1 , K. Ritzen1 , J. Egmond, van1 , E. Franken1 , M. Mast1 , J. van
Santvoort1 , E. van der Wal1 , H. Struikmans1
1
R ADIOTHERAPY C ENTRE W EST, The Hague, Netherlands

1507 poster
THE PROFESSIONAL ROLL OF RADIOTHERAPISTS IN IMPLEMENTING GATING TECHNIQUE: RESPIRATORY DEEP
INSPIRATION BREATH HOLD FOR RADIATION TREATMENT OF
LEFT-SIDED BREAST CANCER PATIENTS
S. Lind1 , M. Baker1 , W. Ottosson1 , N. Hviid1 , H. Landgren1 , U. Hatting1
1
C OPENHAGEN U NIVERSITY H OSPITAL , H ERLEV, Department of Oncology,
Herlev, Denmark
Purpose: In a large radiation therapy department with high demands on
throughput of patients it is a challenge to implement a new and advanced
treatment technique. In the current approach the objective is to describe theentire educational procedure and training of 76 Radiation Therapy Technologists (RTT) to understand and handle respiratory Deep Inspiration Breath
Hold (DIBH) for treating left-sided breast cancer patients.

S 562

R ADIOBIOLOGICAL MODELLINGR ADIOBIOLOGICAL MODELLING

Materials: In 2009 it was decided that DIBH technique should be offered toleft -sided breast cancer patients in our department. Prior to the implementation, an interdisciplinary group of employees (physicists, RTT, oncologists)
visited a radiotherapy centre with long experience in using DIBH-technique.
The implementation group was made up of 2 physicists and 4 RTT. The overall experience of training and visit provided the 4 RTT sufficient knowledge
to compile detailed instructions on how to handle 1) the patient DIBH training
and set-up prior to CT scanning, 2) the first treatment of the patient, 3) the
subsequent treatments. Before clinical implementations, all instructions werereviewed and tested on a phantom. A preclinical study initiated, where only
the implementation group handled a number of pre selected patients to DIBH
training, CT scanning and finally treatment. The RTT implementation grouparranged a one day training program for the rest of the RTT group. The training program contained of theoretical education, software hands-on training
and treatment of patients.
Results: Only half a year after the first treatment, the DIBH technique is now
a standard treatment for all left-sided breast cancer patients, where treatments of 75 patients are already accomplished. Each of the RTT accomplished the one day training successfully. Few of the RTT are not entirely
confident and need more clinical practice to be able to handle the techniqueroutinely. More experienced RTT is always available for collaboration. During
the first step of the implementation an extra 15 min was allocated to eachtreatment slot due to the new technique and additional online image evaluation. After only few patient treatments, this was reduced radically to only
5 min. Besides of being able to handle the DIBH technique, the RTT havegained knowledge in Image Guided Radiation Therapy (IGRT) due to online
daily patient set-up verification, namely acquiring daily electronic portal imaging device (EPID) imaging.
Conclusions: The concept using RTT to train other RTT has been appreciated by the RTT group. Opposed to e.g. physicists, the RTT to a greater
extend, understand the RTT need in terms of e.g. education, support, written procedures etc. Furthermore, the RTT group has felt commitment andresponsibility to the project which makes it easier to continue with future challenges.
1508 poster
USE OF ELECTRONIC TISSUE COMPENSATOR IN HEAD AND
NECK PATIENTS AT TATA MEMORIAL HOSPITAL: OUR EXPERIENCE
G. Biju1
1
TATA M EMORIAL H OSPITAL, Department of Radiation Oncology, Mumbai,
India

Purpose: The surface irregularity of the head and neck cancer patients
mostly leads to an inhomogeneous dose distribution when treated with bilateral fields. Conventionally the tissue compensators were being used toget clinically acceptable distribution. With the advancement of technology
use of Multi leaf collimators (MLC) were also explored to get electronic tissue compensation (ETC). A method using ETC to produce suitably intensity
modulation across the treatment field has been implemented at our centre
Materials: Computed tomography (CT) scan were acquired of head and neckcancer patients selected for ETC treatment. CT images were exported to
Eclipse treatment planning system (TPS) via local area network. Two parallel opposed isocentric bilateral 6MV photon beams with appropriate field size
were placed and 2 Gy dose/fraction was prescribed at isocentre. Fields werereduced at 46 Gy to spare spinal cord and replanned for a total dose of 60 Gy.
Eclipse TPS was used to produce the ETC plan. Electronic tissue compensation were achieved using dynamic MLC. Digitally reconstructed radiographs(DRR) were also generated for patient setup verification. The treatment wasdelivered at Clinac 6EX Linear Accelerator equipped with 120 leaf millennium
MLC.
Results: ETC has been successfully implemented clinically at our centre.
The ETC compared to physical compensator can speed up the treatment andmay reduce skin dose, due to minimal electron contamination
Conclusions: Electronic compensator is much faster and there is no need to
install a physical compensator which takes time for fabrication before execution of each treatment beam. ETCs provided easy implementation and more
flexibility in designing the profiles than the physical compensator method. The
use of ETC also eliminates the need for physical trays and mounting slots inthe linac treatment head. However, since the MLC dynamic mode is involvedin the treatment, an extensive quality assurance should be carried out forindividual plans.
1509 poster
WHICH SKIN MARKING SYSTEM GIVES THE BEST STARTING
POINT WHEN TREATING BREAST CANCER PATIENTS?
A. Schouboe1 , M. H. Andersen1 , M. S. Thomsen2
1
A ARHUS U NIVERSITY H OSPITAL, Department of Oncology, Aarhus C,
Denmark
2
A ARHUS U NIVERSITY H OSPITAL, Department of Medical Physics, Aarhus
C, Denmark

Purpose: In our department Daily Image Guided Radiotherapy (IGRT) is
used when treating most diagnose groups. We deliver 51.000 radiotherapy treatments yearly. Of these approximately 33% are curative breast cancer treatments. In October 2010 the department implemented daily IGRTof breast cancer patients and is now being used on all patients treated forbreast cancer. Some patients have, during daily skin care, applied moisturising cream in the treated area and thereby accidently removed the felt tip
pen markings on the skin. Based on the daily images we have studied the
reproducibility of the isocenter with two different ways of skin marking on thepatient before positioning and prior to IGRT treatment.The purpose is to findthe optimum patient positioning method for the treatment of breast cancer
patients, by comparing the quality of the two different ways of skin marking.
Materials: The patients are positioned on Breast-Board to an isocenter
marked on the patient surface followed by IGRT. One group (A) has - using a felt tip pen -been marked with a default isocenter cross on the skin of
the remaining breast or on the chest wall. The other group (B) is positioned
according to relative coordinates to a default isocenter using three tattooed
dots on the sternum. Both groups are positioned with fixed vertical couch
position. MV kV images are taken, and the RTTs do a daily match on thebone structure followed by couch shift and then deliver the radiotherapy treatment. Couch shift for the two groups between the patient position prior to
imaging and the patient position at the time of actual treatment is comparedby extracting data from Aria.
Results: Until now data from more than 600 consecutive treatments havebeen analysed. This includes both lumpectomy and mastectomy patients.
The vertical couch shift between the imaging position and treated position
is found to be within +/- 5mm for more than 90% of the treatments in bothgroups. The longitudinal couch shift within +/- 5mm is also comparable forthe two groups. In about 90% of the treatments the longitudinal couch shift
does not exceed 5mm. For the lateral couch shift a difference between thetwo groups, with about 10% more treatments within +/- 5mm for patients ingroup B compared to group A. Patients feel more satisfied without the felt
tip pen markings on the skin; it is easier applying moisturising cream in thetreated area.
Conclusions: Obtained with the method with a relative couch shift a better
reproducibility of the isocenter within +/- 5mm is using three tattooed dots on
the sternum compared to skin markers in the treated area. It furthermore
gives greater patient satisfaction and the optimum daily skin care is possible.
RTTs do not have to make skin markings on damaged skin. It is an advantage
to avoid skin markings in the treated area due to the skin care. Over the next
two months further data will be analysed.

Radiobiological modelling
1510 poster
FACTORS AFFECTING THE TIME COURSE OF BYSTANDER
EXPRESSION
N. Suchowerska1 2 , S. Rizvi1 , A. Taychasiraprapakul1 , J. Atyeo3 , M. Ebert4 ,D. McKenzie5
1
S YDNEY C ANCER C ENTRE , R OYAL P RINCE A LFRED H OSPITAL, Department of Radiation Oncology, Camperdown, Sydney, Australia
2
U NIVERSITY OF S YDNEY, School of Physics, Sydney, Australia
3
U NIVERSITY OF S YDNEY, Lidcombe, NSW, Australia
4
S IR C HARLES G AIRDNER H OSPITAL, Nedlands, WA, Australia
5
U NIVERSITY OF S YDNEY, Sydney, Australia
Purpose: In contrast to conventional IMRT, which can take up to 30 minutes
to deliver a single fraction, VMATTM and RapidArcTM enable complex treatments to be delivered within minutes. The effect of these rapid treatmentson bystander expression has not been explored. The purpose of this study
is to identify the time course of bystander expression by medium transfer
experiments, providing experimentally derived parameters for more accurate
radiobiological modelling.
Materials: A human non-small cell lung cancer cell line (NCl-H460) was irradiated with a 6MV photon beam produced from a Varian IX linear accelerator
to doses of 2, 4, 6 and 8 Gy. These cells were termed donor cells. At selected time intervals after exposure (5, 15, 30 and 60 minutes), the medium
was transferred to receiver cells of the same cell line in separate flasks. The
clonogenic survival fraction of the receiver cells was determined following 5days of incubation. The experimental design controlled for the density of cells
in the donor flask, the effects of irradiation on the medium alone and included
a sham exposure.
Results: The results show a strong time course for the bystander signal expression, which is dependent on the density of cells in the donor flasks. Following lethal doses of radiation to the donor cells, the response in the receivercells is proliferative (Figure 1). Sub-lethal doses of radiation result in a proliferative response when medium transfer is carried out at 15 minutes after
exposure [SF15], but a toxic response when medium transfer is carried out
after 60 minutes [SF60]. A higher cell density in the donor flasks produces

an increased response in the receiver flasks for the same volume of mediumtransferred.

S 563

1512 poster
INTEGRATING DOSIMETRY AND BIOMARKERS VIA A BAYESIANNETWORK FOR PREDICTING RADIOTHERAPY RESPONSE IN
LUNG CANCER
J. Oh1 , J. Craft1 , R. Al-Lozi1 , M. Vaidya1 , Y. Meng1 , J. Bradley1 , J. Deasy1 ,I. El Naqa21
1
WASHINGTON U NIVERSITY S CHOOL OF M EDICINE, Radiation Oncology,
St. Louis, USA
2
M C G ILL U NIVERSITY, Medical Physics, Montreal, Canada

Conclusions: We propose that bystander signals, positive to cell survival,
are immediately released when a cell enters a fatal trajectory following irradiation. Negative bystander signals are released later, within 60 minutes ofthe exposure and correspond to the bystander effect observed by Mothersill and Seymour (1997; 1998). This study shows that the treatment fractiondelivery time could affect radiation response through bystander signaling. A
long delivery time will allow cells to respond to the early bystander signals,
even while the treatment is being delivered. An understanding of the signaling
time course enables the process to be modelled and permits intervention to
consolidate or prevent either positive or negative bystander responses. AcknowledgmentThis work is supported by a New South Wales Cancer Council
Project Grant
1511 poster
IMAGEBASED COMPUTATIONAL SIMULATION OF TUMOUR RESPONSE TO RADIOTHERAPY
I. Espinoza12 , P. Peschke3 , C. Harting1 , C. P. Karger1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Medical
Physics in Radiation Oncology, Heidelberg, Germany
2
P ONTIFICIA U NIVERSIDAD C ATÓLICA DE C HILE, Department of Physics,
Santiago, Chile
3
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Clinical Cooperation Unit
Radiation Oncology, Heidelberg, Germany

Purpose: In radiotherapy, it is important to predict the response of tumourand normal tissues to irradiation prior to the treatment. This is currently doneusing the physical dose distribution in the patient. Mathematical modelling of
tumour control probability (TCP) based on this dose distribution may help toimprove this prediction and to optimize the treatment plan. The aim of thiswork is to develop an imagebased 3D radiobiological model, which describes
the growth and the response to radiotherapy of clinical tumours.
Materials: The model is based on voxels, containing tumour, normal anddead cells. Killing of tumour cells due to irradiation is calculated by the LinearQuadratic Model, and the proliferation and resorption of cells are modelledby exponential laws. The initial shape of the tumour is taken from Xray computed tomography (CT) images. Including the fractionation regime and thephysical dose distribution of the radiation treatment, the model simulates thespatialtemporal evolution of the tumour, considering geometrical constrainsin the surroundings, like bone and air. The effect of hypoxia on cell death isconsidered as well, and several models for calculating oxygen distribution intumours (and its relationship to capillary cell density) are studied.
Results: The model describes the temporal behavior of the tumour including growth and radiation induced change of tumour cell density as well aschanges in oxygen partial pressure. The results can be displayed as a
3Dmap. Based on the response the "volume versus time" curves the development of the tumor may be described. By simulating many tumors, TCP
may be estimated.
Conclusions: The simulation model may contribute to the understanding of
the influence of biological tumour parameters on tumour response during andafter treatment, and specifically on TCP. Ongoing work will additionally consider other important issues, like proliferation and hypoxia maps from PET(Positron Emission Tomography) and MRT (Magnetic Resonance Tomography) images. After this is fully incorporated, the model needs to be validated
in radiation experiments with experimental tumors as well as with clinicalcases. This study is supported by a grant from the Ministry of Educationof Chile, Programa Mece Educaciperior (2).

Purpose: Despite many efforts to develop new dose-volume models for early
detection of tumor local failure in non-small cell lung cancer (NSCLC) patients, there was no significant improvement in their application prospectively.
Based on recent studies of biomarker proteins’ role in hypoxia and inflammation in predicting tumor response to radiotherapy, we hypothesize that combining dosimetric and biological factors with a suitable framework could improve the overall prediction. To test this hypothesis, we propose a graphical Bayesian network framework for predicting local failure in NSCLC postradiotherapy.
Materials: A Bayesian network is a probabilistic graphical model that encodes a joint probability distribution among variables of interest, which enables easy visualization and interpretation of interactions among these variables for clinical use. The proposed network approach was tested using two
different datasets of locally advanced NSCLC patients treated with radiotherapy. The first dataset (n=56) was collected retrospectively, which is comprisedof clinical and dosimetric variables only. The second dataset (n=18) was collected prospectively in which in addition to clinical and dosimetric information,
blood was drawn from the patients at various time points (before, during, andat follow-ups) to extract candidate biomarkers as well.
Results: Using our proposed Bayesian network approach, with the firstdataset, an accuracy (acc) of 80.18%, Matthew’s correlation coefficient (r) of
0.5818, Spearman’s rank correlation coefficient (rs) of 0.5811, and the area
under the receiver operating characteristic (ROC) curve (AUC) of 0.8201 wereachieved, which was much better than the performance of other competing
Bayesian-based classifiers. With the second dataset, the combined model
had a slightly higher performance compared to individual physical and biological models, with the biological variables making the largest contribution.
The combined model achieved an acc = 87.78%, r = 0.74, rs = 0.75, and AUC= 0.9527 on leave one-out cross-validation analysis.
Conclusions: We have investigated an integrated network approach basedon Bayesian statistics for predicting post-radiotherapy local failure in NSCLC
patients. Our preliminary results show that the proposed method can be used
as an efficient method to develop predictive models of local failure in thesepatients and to interpret relationships among the different variables in themodels.
Supported by NIH grant K25CA128809 and Fast Foundation.

1513 poster
INVESTIGATION OF DOSE AND TIME DEPENDENCE OF THE
INDUCTION OF DIFFERENT TYPES OF CELL DEATH IN A SMALL

S 564SRS-SBRTR ADIOBIOLOGICAL MODELLING

CELL LUNG CANCER CELL LINE
N. Makris1 , M. Edgren1 , P. Mavroidis1 , B. Lind1
K AROLINSKA I NSTITUTET AND S TOCKHOLM U NIVERSITY, Department ofMedical Radiation Physics, Stockholm, Sweden
1

Purpose: The aim of this work is to quantify and model various types ofcell death for a small cell lung cancer (SCLC) cell line (U1690) after exposure to a 137 Cs source and to compare different cell survival models, namely
the Linear-Quadratic (LQ) and Repairable Conditionally Repairable model(RCR).
Materials: This study is based on four different experiments that took placeat the Cancer Centrum of Karolinska (CCK). A human’s small cell lung cancer(SCLC) cell line (U1690) underwent exposure to a 137 Cs source, followed bya standard colony formation assay. Additionally, for the determination andquantification of various modes of cell death, the method of fluorescencestaining was implemented. Using this method, the cell death based on morphological characteristics is categorized. Subsequently, using flow cytometry
analysis, the properties of individual particles and more specifically the percentage of cells in each phase of the cell cycle was measured. The quantification of senescent cells was performed by staining the samples with senescence associated-β -gal solution and then by scoring as senescent cells those
who had incorporated the substance. A mathematical model was introduced
for sorting the different modes of cell death into (three categories) apoptotic,
senescent and other types of cell death.
Results: Regarding the clonogenic cell survival assay, the RCR model
showed a χ2 value that is equal to 6.10 whereas for the LQ model χ2 =9.61. Moreover, from the fluorescence microscopy and senescence assay
we observed an initial increase of the response probability for all categories
of cell death on day 2, which reaches saturation at higher doses. On day 7 asignificant induction of apoptosis in a dose and time dependent manner was
evident (see figure below, which shows the apoptotic probability in response
to dose (0, 1, 2, 3, 5, 8 Gy) and time (2, 7, 14 days)), whereas senescence
was slightly increased in response to dose but not to time. Regarding the’other types’ of cell death on day 7, they showed a higher response probability than that on day 2 as well as a prominent dose dependence. A dose
dependent accumulation of cells in the G2/M phase of the cell cycle was induced by photons on day 2. The accumulation in the G2/M phase on day
2 is released on day 7 and simultaneously an increase in the probability of
apoptosis with time was observed.

Conclusions: The RCR model fits better to the experimental data rather
than the LQ model. On day 2 there is a slight increase of the apoptotic andsenescent probability with dose. On the other hand, on day 7 the shape ofthe dose-response curve of apoptosis differs and a sigmoidal increase withdose is observed. At both time points the mathematical model fits reasonably
well to the experimental data. Due to the fact that the clonogenic survival
doesn’t coincide with the one extracted from the fluorescence microscopy, amore accurate way of quantifying cell death needs to be applied.
1514 poster
LINEAR QUADRATIC TUMOR CONTROL PROBABILITY MODELINGOF HYPOXIA DOSE PAINTING WITH HEAVY IONS
E. Malinen1 , A. Soevik1
1
R ADIUM H OSPITAL, Department of Medical Physics, Oslo, Norway
Purpose: To estimate the tumor control probability (TCP) of hypoxia dose
painting with heavy ions of intermediate to high linear energy transfer (LET),
and to compare the estimate with that from dose painting using photons of
low LET.

Materials: A TCP model based on the linear quadratic cell survival formalism was developed. The model requires intratumoral distributions of cellularradiosensitivity and absorbed dose. Tumor images tentatively depicting hypoxia were utilized. The dependence of the cellular radiosensitivity on thepartial pressure of oxygen and the LET was incorporated in the modeling.
Optimizing TCP under the constraint of constant integral tumor dose, optimaldose prescription maps were obtained. The dependence of the dose maps
on LET was investigated. Also, the resulting TCP was compared to that fromconventional therapy. The therapeutic gain DTCP was calculated as the difference in TCP between dose painting and conventional therapy at the same
integral tumor dose. Replanning, that is, modification of the treatment plan
during therapy according to changes in the spatial hypoxia distribution was
also considered.
Results: TCP following dose painting was improved compared to that following conventional radiotherapy with the same integral tumor dose, irrespectiveof LET. The optimal dose distribution became more homogenous and the resulting therapeutic gain from dose painting was reduced with increasing LET.
However, the therapeutic gain from dose painting was only modestly reduced
from low LET (0.1-5 keV/um) to intermediate LET (10-30 keV/mm, typical oftherapeutic carbon ions). The importance of replanning diminished with increased LET.
Conclusions: Dose painting of hypoxic tumors with particles such as carbon
ions may be warranted, despite the fact that the oxygen enhancement ratio is
reduced with increasing LET.
1515 poster
LOCALIZED CT-GUIDED IRRADIATION INHIBITS NEUROGENESISIN SPECIFIC REGIONS OF THE ADULT MOUSE BRAIN
E. Ford1 , P. Achanta2 , M. H. Jang3 , H. Song3 , A. Quinones-Hinojosa2
1
J OHNS H OPKINS U NIVERSITY, Department of Radiation Oncology andMolecular Radiation Sciences, Baltimore, USA
2
J OHNS H OPKINS U NIVERSITY, Neurosurgery, Baltimore, USA
3
J OHNS H OPKINS U NIVERSITY, Neurology, Baltimore, USA
Purpose: Radiation inhibits ongoing neurogenesis in the adult brain. This
has important clinical implications for patients undergoing radiation therapy
for CNS malignancies. As a laboratory tool, radiation can also be used tomodulate neurogenesis for a variety of experimental studies. We describe
the use of a dedicated CT-guided precision device to irradiate specific subregions of the adult mouse brain, measuring the accuracy with which radiation
can be delivered in tissue samples, and showing that localized irradiation
inhibits neurogenesis.
Materials: The two neurogenic region of the C57/BL6 mouse brain were studied: the dentate gyrus (DG) of the hippocampus and the subventricular zone
(SVZ) of the lateral ventricles. Visualization of these brain structures on CT
was accomplished with intrathecal injection of iodinated contrast agent, which
enhances the lateral ventricles. T2-weighted MRI images were also used fortarget localization. Visualization of delivered beams (10 Gy) in tissue wasaccomplished with immunohistochemical staining for the protein γ H2Ax, amarker of DNA double strand breaks. Cellular proliferation was quantified
with staining for Ki-67. Neurogenesis in the DG was quantified with pulselabeling with the nucleoside analog EdU at four weeks following irradiation (10Gy) and then sacrifice four weeks later and staining for the neuronal marker,
NeuN.
Results: γ H2Ax stains showed that the lateral ventricle wall could be targeted with an accuracy of 0.19 mm (n = 10). γ H2Ax staining showed thatthe DG can be unilaterally irradiated with a localized arc treatment. Radiation
resulted in a significant decrease of proliferative neural progenitor cells as
measured in Ki-67 staining (p < 0.001) while leaving the contralateral side intact. EdU/NeuN double labeling showed that neurogenesis was significantly
reduced in the DG (p < 0.001).
Conclusions: Localized radiation can inhibit neurogenesis long term in therodent brain. This is in contrast to previous studies which have used wholebrain irradiation and invoked an inflammatory response as the mechanism
for inhibiting neurogenesis. Localized radiation is a promising new tool forthe study of neurogenesis and may be used to mimic clinic radiation therapy
treatments.
1516 poster
RADBIOMOD: AN EXCEL-BASED RADIATION BIOLOGICALMODELLING TOOL FOR THE EVALUATION OF RADIOTHERAPYTREATMENT PLANS
J. Chang1 , D. Lim Joon1 , C. Hamilton1 , V. Khoo2
1

AUSTIN H EALTH, Radiation Oncology Centre, Heidelberg West, Melbourne,
Australia
2
T HE I NSTITUTE OF C ANCER R ESEARCH AND T HE R OYAL M ARSDENNHS F OUNDATION T RUST, Department of Clinical Oncology, Sutton, United
Kingdom
Purpose: Most radiotherapy treatment plans (RTP) are currently evaluatedon the basis of Dose-Volume-Histogram (DVH) parameters. Evaluating planspurely by DVH parameters can be limited in predicting clinical outcomes. A
potentially superior method for predicting clinical outcomes is using biologicalmodelling; however this approach has not been clinically validated. Possible
limitations to the clinical validation of biological modelling are the complexity
and technical skills required to implement some of these models, which often
restricts clinician involvement in this area of research without adequate apriori training. As such, a user-friendly biological modelling tool based on
Microsoft Excel has been created to easily and quickly evaluate radiotherapy
plans using multiple biological models simultaneously.
Materials: This program was developed using VBA for Microsoft Excel. For tumour control probability (TCP) modelling, the following models
were incorporated: the Poisson-based modified Webb and Nahum model(TCP_WN), the modified Zaider and Minnerbo model (TCP_ZM), and the Gay
and Niemierko model (TCP_GN). For normal tissue complication probability (NTCP) modelling, the following models were incorporated: the LymanKutcher-Burman model (NTCP_LKB) and the Gay and Niemierko model(NTCP_GN). For probability of uncomplicated control (PUC) modelling, thefollowing models were incorporated: the standard model and the Agren et
al model. Formulas for generalised equivalent uniform dose (gEUD) werealso included. Where other biological modelling calculators with equivalentmodels were available, RadBioMod was compared to these using correlation
coefficients for common data.
Results: With Microsoft Excel being the operating environment, RadBioMod
provides a familiar environment for clinicians to evaluate treatment plans
based on biological models. This tool allows quick and easy calculation ofmultiple biological models simultaneously. It also allows the flexibility and customisability of Excel, allowing multiple statistical analyses, as well as graphingof the biological models. Compared with "Bioplan", TCP_WN and NTCP_LKB
had correlation coefficients of 0.998 and 1.00, respectively. Compared to "eudmodel", TCP_GN and NTCP_GN had correlation coefficients of 1.00 and
1.00, respectively.
Conclusions: RadBioMod is a powerful and user-friendly tool that allows
clinicians to quickly and easily evaluate their RTP using biological models. It
shows excellent correlation with currently available calculators and as suchpermits an awareness of the estimations from each of the used models simultaneously. This should facilitate understanding and further research byclinicians into this important area.
1517 poster
SENSITIVITY OF BIOLOGICAL OPTIMIZATION TO TCP PARAMETERS FOR SIMULTANEOUS BOOST ON INTRA-PROSTATICLESIONS
R. Azzeroni1 , A. Maggio1 , C. Fiorino1 , P. Mangili1 , C. Cozzarini2 , N. Di
Muzio2 , R. Calandrino1
1
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Medical Physics, Milan, Italy
2
S AN R AFFAELE S CIENTIFIC I NSTITUTE, Radiotherapy, Milan, Italy
Purpose: To assess the potential of biological models in IMRT planning optimization and to evaluate the impact of TCP model parameters on plan quality
when performing a SIB on one or more DILs.
Materials: 6 intermediate/high risk prostate cancer patients (pts) were submitted to T2WI, T1WI and DWI MRI: imaging showed evidence of one DIL infour pts and two DILs in three pts in the peripheral zone. PTVDIL was obtained by 5 mm isotropic expansion of DIL. Based on the assumption that local failures are mainly due to highly radioresistant clonogens within the DILs,
we considered different parameters for DILs and the prostate outside DILs
(CTV). In the Poisson-like model used during optimization, we assessed thefollowing values: TD50=57.3 Gy and 68.3 Gy for CTV and TD50=82.3 Gy and
95 Gy for DIL. Values of γ 50 ranging between 4 and 8 and a/b=10 were considered, consistently with the hypothesis that inter-patient dose-effect variability is mainly due to the presence of resistant DILs. Different combinations of these parameters were tested with the aim of maximizing TCP whileconstraining NTCPs below 5%. A coplanar 6 MV 9-field arrangement wasused and the number of fractions was fixed to 28, following our hypofractionated protocol: planning were optimized using the recently available biological optimization and evaluation module of the Varian Aria-Eclipse system;
NTCP/TCP calculations were also compared with the corresponding results
using independent softwares (Bioplan, Biosuite).
Results: For all parameters combinations, TCP values ranged between
38,4% and 99.9%; the optimized median physical doses obtained by
the system were around 90-120 Gy and 70-78 Gy for DIL and CTV
respectively, depending on the parameters applied.
In Fig.
1 the
TCP corresponding to the prostate CTV. Rectum and bladder werealways well spared for both patients (NTCP(bladder)contracture<1,5%,
NTCP(rectum)bleeding<9.8%, NTCP(anal canal)incontinence<3.9% and
NTCP(femoral heads)necrosis<0.3%). The simulations showed that the proximity of the DIL to the rectum and overlap rectum-prostate size involves a dramatic decrease of TCP in the case of very radioresistant DIL (TD50=95Gy,
patients 2 and 4 in the Figure).

S 565

Conclusions: Biological optimization in IMRT treatment planning holds
tremendous promise for improving tumor cell killing while minimizing normal
tissue damage. Caution should be exercised in choosing appropriate models
and/or model parameters and in evaluating the plan obtained when using thebiologically based treatment planning system. Acknowledgments: The study
was supported by a Varian research grant
1518 poster
SYSTEMS BIOLOGY OF MITOGENIC SIGNALING: A MOLECULARBASIS FOR ONCOLOGY AND RADIOLOGY
N. M. Borisov1 , N. Kuzmina1 , N. Bogovalova1 , Z. Galyautdinova1 , N.
Gromova1 , A. Krupnov1 , A. Zyablitsin1
1

B URNAZYAN F EDERAL M EDICAL P HYSICAL C ENTER, Clinical Departmentof Radiation Medicine, Moscow, Russian Federation

Purpose: Qualitative investigation for stochastic consequences (mostly malignant tumors and leukemia) of radiation exposure is one of the most controversial topics in medical radiology. Long-lasting lack of expert consensus on
the existence of dose threshold for radiation-induced cancer (which is tried to
be derived from both radiation epidemiology and experimental radiobiologydata) attracts attention to the fundamental problems of molecular biology of
mitogenesis that may be helpful in this difficult case, when classical methodsof medical observation and animal experimentation show constant inability.
Materials: Purely experimental methods, including western blotting, siRNA
depletion of certain proteins in the cell, mutant cell production etc may not
be sufficient in molecular biology of mitogenic cell signaling since measurements of protein-protein interactions between dozens of molecule types may
be required for exhaustive research of signal propagation. Nevertheless, involvement of in silico analysis for the chemical kinetics of protein-protein interactions during signal transduction in the normal and malignant cell may beessentially helpful in molecular oncology.
Results: During the past decade, we have developed and put into the agreement with experimental data a set of complex network models for mitogenic
and survival pathways that are initiated by epidermal growth factor (EGF)
and insulin stimulation. We have shown experimentally that in HEK293 cellline insulin does not cause activation of extracellular signal-regulated kinase(ERK), although it considerably amplifies the ERK response upon EGF stimulus. We have hypothesized that the crucial role for this amplification is playedby the adapter protein GAB1, which is recruited to the plasma membrane
via phosphatidylinositol-3,4,5-triphosphate (PIP3). Our hypothesis was confirmed during the series of experiments on western blotting, inhibition of the
keystone enzymes in signaling pathways, as well as siRNA-based depletionof the keystone proteins.Recently, we extended our investigations and fitted
according to the measurements a highly-branched (developed using the rulebased software tool in systems biology, BioNetGen 2) network model that
includes most complexes and reactions that may emerge during signal propagation.
Conclusions: Although this novel model contains more than 650 complexes
and 5500 reactions, we showed the ability the handle this complexity, evenusing manual parameter fitting. The results of model fitting suggest ideas on
the details of protein-protein interactions, such as preferable sites/domains
for binding one another, sequestration of active enzymes via binding to hugeprotein complexes etc. Plans for experimental validation of modeling results
include detection of phosphotyrosine residues in simultaneous Grb2-GAB1
precipitate or production of tyrosine-to-phenylalanine mutations in mice.

SRS-SBRTS 566SRS-SBRT

SRS-SBRT

1519 poster
A PLAN ROBUST ANALYSIS FOR AVM TREATMENTS USING A
TOMOTHERAPY UNIT
G. Guidi1 , E. Cenacchi1 , F. Bertoni2 , T. Costi1
1
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Medical Physics, Modena,
Italy
2
A Z .O SPEDALIERO -U NIVERSITARIA DI M ODENA, Radiation Oncology,
Modena, Italy
Purpose: The aim is to verify the feasibility of the AVM (Arteriovenous Malformation) radiosurgery using a Tomotherapy unit without a head invasive frame.
Using a plan robust analysis, we have evaluated few cases, to compare thelower, mean and upper limit of doses delivered. We have simulated an helicaltreatment and a potential setup error due to the immobilization device. We
have evaluate the risks of dose missing in case of contours using MRI (AVM)
and orthogonal images (AngioROI) acquired by the Angio-Rx exams.
Materials: Previous AVMs treated using a LINAC with microMLC and headinvasive frame, are re-planned using a Tomotherapy unit. 20Gy are prescribed to 95% of the AVMs volume and 18Gy is the minimum accepted.
The AVMs volume are contoured using the co-registration of the MRI andCT exams. The AngioROI are contoured using planar images obtained by
an Angio-Rx exams and superimposed to the CT projection. Using CERR
(WUSTL University) and a plan robust analysis, we have simulated the stability of the treatment assuming a mean setup error (-1.2mm,-0.1mm,1.7mm)
due to the non use of invasive head frame. The mean setup error is been
calculated by previous work of the author based on 21 radiosurgery recorded
using a MVCT co-registration and delivered using a Tomotherapy Unit and athermoplastic mask as immobilization devices.
Results: The contoured volume are similar and no difference are evident asreported into the conclusion. The table show the results of the plan robust
analysis using a single fraction and 1000 trials of simulation.

The data of the robust analysis show discrepancies only for the min dose, but
no incongruity are highlighted for upper, mean and lower bound. Considering
the 18Gy as a minimum dose request, all the volume are covered adequately.
Conclusions: The AngioROIs contoured using orthogonal planar images are
smaller than the AVMs contoured using the MRI images but equal considering
the resolution of the systems used to calculate and delivery the doses. Only
few voxel of discrepancy (<0.5cc) are highlighted by the different method ofcontouring and are smaller than the grid dose dimension (2.15x2.15x2mm).
Anyway the helical delivery can guarantee to delivery the dose prescription
and the minimum dose of 18Gy to both the volume without geographic missing, even considering possible setup error. The robust analysis has showed
the possibility to treat the patients without the use of invasive head frame andincrease the comfort of the patient, maintaining accuracy and safety procedures
1520 poster
COMPARATIVE DOSE-VOLUME ANALYSIS FOR FRACTIONATED
RADIOTHERAPY OF CENTRAL BRAIN TUMORS IN PEDIATRICPATIENTS USING CYBERKINFE, IMRT, AND BRAINLAB
J. Heinzerling1 , C. Timmerman1 , Z. Hong2 , E. Ramirez1 , C. Ding1 , R.
Foster1 , T. Solberg1 , R. Timmerman1
U NIVERSITY OF T EXAS S OUTHWESTERN M EDICAL C ENTER, Radiation
Oncology - Cancer Care Pavillion, Dallas, USA
2
U NIVERSITY OF T EXAS S OUTHWESTERN M EDICAL C ENTER, Biostatistics,
Dallas, USA
1

Purpose: Pediatric patients (pts) with low grade central brain tumors are
typically treated with fractionated IMRT (FIMRT). The purpose of this study
was to identify potential dosimetric advantages in target coverage and organ
at risk (OAR) dose in the setting of image-guided, fractionated stereotactic
radiosurgery (FSRS) with reduced margins compared to FIMRT.
Materials: 10 pts were selected with central brain tumors previously treatedto a dose of 45-50.4 Gy in 25-28 fractions. Pts were re-contoured to include
unique organs at risk. GTV and OAR volumes were delineated utilizing MRICT fusion. Three methods of treatment planning were carried out for eachpt: for FSRS, pts were planned utilizing both Cyberknife Multiplan (CK) andBrainLab IMRT with iPlan (BL), and were compared to FIMRT planned with
Pinnacle. The GTV was expanded by 5 mm for FIMRT planning, but becauseof the availability of daily image guidance, no PTV margin was added for
either CK or BL planning (i.e. GTV=PTV) in order to simulate actual treatment

conditions. FIMRT plans were generated using 6 non-coplanar beams with
Pinnacle version 8.0m. Inverse planning was used and plans were optimized
to achieve optimal PTV coverage while minimizing OAR doses to at least
those consistent with institutional dose constraints, and plans were typicallyprescribed to 95-100%. For CK, one to two collimators were used to provide
highly conformal dose distributions, and plans were typically prescribed to
the 50-70% isodose line. For BL, 7 noncoplanar beams were generated andplans were typically prescribed to 95-100%. All plans were prescribed to adose of 45 Gy in 25 fractions. Dose volume analysis for various endpoints
was performed and comparative analysis was done using SAS (Cary, NC).
Results: Significant improvement was observed for FSRS compared to
FIMRT for the following OAR parameters: mean dose, minimum dose, anddose to 2 cc of brainstem; mean dose and dose to 2 cc of caudate; max,mean, minimum, and dose to 5 cc of cerebellum; mean dose, dose to 10
cc of cerebrum, and volume of cerebrum receiving 12 Gy; minimum doseto the optic chiasm; max dose, mean dose, and dose to 0.5 cc of the hippocampi, max, mean, and minimum dose to the bilateral optic nerves andtracts; minimum dose to the pineal gland, mean and minimum dose to thepituitary gland, mean dose and dose to 2 cc of putamen; mean dose anddose to 2cc of thalamus. For the two FSRS planning methods, CK resulted
in significant reduction in dose to 10 cc of cerebrum and volume of cerebrum
receiving 12 Gy.
Conclusions: FSRS with image guidance allows reduction of margins andresults not only in reduction of dose to adjacent OAR, but also to novel structures away from the target compared to FIMRT planning for treatment of central brain tumors in pediatric patients. Less OAR dose may translate into decreases in late toxicity in pediatric patients and will be evaluated in a prospective clinical trial at our institution.
1521 poster
COMPARISON OF CONVENTIONAL VS. SOFTWARE-BASEDMETHODS FOR RAPID-ARC BASED SRS QA
A. Etemadnia1 , H. Yampolsky2
1
S AINT J OHN ‘ S H OSPITAL, Physics, Santa Monica, USA
2
VALLEY R ADIOTHERAPY A SSOCIATES M EDICAL G ROUP, I NC., Center for
Radiation Therapy of Beverly Hills, El Segundo, California, USA
Purpose: Rapid Arc is a volumetric modulated are therapy delivery system
which delivers dose through upto 360 degree rotation using 177 control points
per arc with five degrees of freedom. These are modulations of dose rate,
gantry angles, field sizes, gantry speed & the multi-leaf collimator. As a result,it presents a unique set of challenges when it comes to performing standard
quality assurances (QA). This task spans further in the case of stereotactic
radiosurgery (SRS) using the rapid arc delivery method due to higher dose
per fraction, steep dose gradients & smaller field sizes. From QA perspective,
this translates into methods & equipment that could ensure adequate QA
which is critical to patient safety. In this study, we have evaluated methods ofRapidArc SRS QA performing Absolute Dosimetry and Relative Dosimetry.
Materials: We have performed absolute measurements using Standard
Imaging‘s Exradin A16 thimble chamber with a collective volume of 0.007
cc. The relative dosimetry has been performed using Kodak EDR2 film in
conjunction with the RIT software. These results have been compared to a
portal dosimetry based collection method using the Dosimetry Check (DC)software. QA was performed on 18 treatment plans using chamber & film.
The same plans were delivered & analyzed using the DC software. Dose &gamma index (3mm/3%) deviation from the expected values were evaluatedfor each method.
Results: The absolute dosimetry method using the chamber resulted in an
average difference of 1.2% with a SD of 2.1% vs. the absolute dosimetry
method using the DC with an average of -0.2% difference with a SD of 2.8%
from the predicted values. The relative dosimetry method using the film resulted in an average of -0.8% difference with a SD of 1.8% vs. the relative
dosimetry method using the DC with an average of 0.9% difference & a SDof 1.0% from the predicted values.
Conclusions: DC successfully performs QA demonstrating comparable results when compared to conventional methods of QA. The advantage mainly
lies in logistic factors such as single exposure absolute & relative results aswell as systematic advantages such as detector dimensions (averaging effects) & their spread (detectors/mm), film saturation, processing complexities, cable noises & performing manual shifts on multiple targets with single
isocentre treatments which would not be of concern using DC. In addition,
DC reconstructs dose on original CTs as well as a DVH comparison of organs contoured using the same measured data.
1522 poster
COMPREHENSIVE VERIFICATION OF THE LINAC ISOCENTRE FOR
STEREOTACTIC RADIOSURGERY USING CINE-EPID AND ARC

DELIVERY
P. Rowshanfarzad1 , M. Sabet1 , D. O’Connor1 , P. Greer21
T HE U NIVERSITY OF N EWCASTLE, School of Mathematical and PhysicalSciences, Newcastle, Australia
2
C ALVARY M ATER N EWCASTLE H OSPITAL, Radiation Oncology, Newcastle,
Australia

1

Purpose: Linac based stereotactic radiosurgery (SRS) and radiotherapy(SRT) are increasingly used for the treatment of small lesions especially brain
tumours. An accurate technique is necessary to ensure that the displacementof the centre of treatment beam is within the accepted criteria (±1 mm) for all
gantry, collimator and couch angles, due to the mechanical flex of the linac
system. At present the routine tests include using mechanical pointers or taking images of the Winston-Lutz phantom on film; both being time consuming
and inaccurate methods. The aim of this study is to introduce an easy andefficient method for verification of the isocentre position for SRS during arc
treatments using cine-EPID and arc delivery.
Materials: The Winston-Lutz phantom was positioned at the isocentre of a
Varian Trilogy linac using the room lasers with a 3 cm diameter collimator. The
collimator was fixed to the gantry head. Images were acquired by a Varian
aS1000 EPID during a 360◦ gantry rotation (clockwise and counter clockwise) using the cine-imaging mode. A robust MATLAB code was developed
to analyse the data by finding the centre of the field and the centre of theball bearing shadow in each image with sub-pixel accuracy. The distance between these two centres was determined for every image and converted intoroom coordinates. The repeatability and reproducibility of the method were
tested. The effect of collimator and couch rotations were also investigatedby taking integrated images at some angles. The method was validated bycomparison to measurements made by the routine QA procedure (using amechanical pointer and a Vernier) and also by manually applying 2 mm displacement to the phantom and checking the algorithm result for the detecteddisplacement.
Results: The average of 3 successive measurement series in clockwise andcounter clockwise directions followed similar patterns and had an RMSD of60, 50 and 20 µm in x, y and z directions, respectively. The maximum displacements of the isocentre were 0.5, 0.6 and 0.4 mm in x, y and z directions
and the maximum radial displacement of the isocentre, was 0.7 mm. The
method was repeatable within 3 µm, and reproducible within 86 µm in static
mode and 35 µm in arc mode. The comparison of this method with routine
tests showed an agreement within 0.2 mm. The largest displacement of theisocentre due to collimator rotation was 0.2 mm and the largest displacement
due to the treatment table rotation was 0.7 mm.
Conclusions: The method introduced in this study has a much higher accuracy, is quick, comprehensive and independent of the observer. It is desirable
to use such accurate methods for pretreatment QA of the isocentre for stereotactic treatments.
1523 poster
CONFORMAL STEREOTACTIC RADIOSURGERY: PLAN EVALUATION METHODS AND RESOULTS
P. Kovacs1 , Z. Sebestyén1 , R. Farkas1 , S. Bellyei1 , A. Szigeti1 , Z. Horváth2 ,T. Dóczi2 , L. Mangel1
1
U NIVERSITY OF P ECS, Department of Oncotherapy, Pecs, Hungary
2
U NIVERSITY OF P ECS, Department of Neurosurgery, Pecs, Hungary
Purpose: Objective evaluation of micro-multileaf collimator (mMLC) basedstereotactic radiosurgery treatment plans.
Materials: 47 patients, 71 lesions received static beam conformal stereotactic radiosurgery treatment in our institute between November 2005 andJune 2008 Target volume and organs at risk were outlined on a MRI-CTR fusion basis. BrainSCAN 5.31 system (BrainLAB AG, Heimstetten, Germany)
was used for treatment planning, Elekta Presice TS linear accelerator (Elekta
Oncology Systems Ltd, Crawley, UK) and BrainLAB m3 mMLC were used
for treatment delivery. An invasive head frame and four screws which were
mounted to the treatment table were used for patient head fixation. Treatment plans were objectively and qualitatively analysed with conformity (CI),dose-homogeneity (HI), leasion coverage (LCF) and healthy tissue relative
overdose (HTOF) tools. Dependency tests were made between CI, HI andthe geometrical parameters of the target volume (size LV, location LOD,
deformity LDI).
Results: Mean conformity was 0,52 (SD 0,13), dose-homogeneity was 1,16
(SD 0,1), healthy tissue relative overdose was 0,88 (SD 0,53), leasion coverage was 0,94 (SD 0,11). Statistically CI depends on (p < 0,001), HI isindependent from LV, LOD, LDI (p = 0,94; 0,14 and 0,72).
Conclusions: Target coverage and dose-homogeneity parameters reach thetreatment requirements. Conformity and healthy tissue relative overdose values are similar to the literary data. Conformity is influenced by the geometricalparameters of the target volume (size, location, deformation), however they
have no effect on dose homogeneity. The used static beam conformal technique is on a par with other techniques in treating small intracranial lesions.
According to our results, similar to the commonly used arc-irradiation andgamma-knife therapy, static beam conformal stereotactic treatment is suitable
for radiosurgery treatment of brain malignancies.

S 567

1524 poster
CYBERKNIFE ROBOTIC RADIOTHERAPY FOR RECURRENTGLIOBLASTOMA MULTIFORME
N. Kucuk1 , A. Kilic1 , C. Ceylan1 , H. Bas1 , M. Guden1 , T. Suzer2 , K. Engin1
1
A NADOLU S AGLIK M ERKEZI, Radiaotherapy and Oncology, Gebze /Kocaeli, Turkey
2
A NADOLU S AGLIK M ERKEZI, Department of Neurosurgery, Gebze /Kocaeli, Turkey
Purpose: One of the most common and aggressive primary malign brain tumor is glioblastoma multiforme (GBM). The standard treatment is complete(if possible) surgical resection and concomitant chemoradiotherapy. Stereotactic radiotherapy is commonly used in patients with recurrent GBM to complement traditional treatments. With developing technologies, it is possible todeliver high dose directly to recurrent tumor with acceptable toxicity. The purpose of this study was to evaluate the clinical results of robotic radiotherapy
in recurrent GBM.
Materials: 45 patients with recurrent GBM were treated by CyberKnife
stereotactic robotic radiotherapy between August 2005 and September 2010.
The mean age was 49 (10-72). 14 (31%) patients were female and 31 (69%)
patients were male. 43 patients were underwent craniotomy and resection. 2
patients had only stereotactic biopsy. Tumor was completely resected in 12(27%) patients. 73% (33) of patients had partial resection. All patients hadreceived prior radiation (54Gy-64 Gy). 16 (35,5%) patients were re-operated
because of local recurrence before CyberKnife treatment. All patients had received chemotherapy during CyberKnife treatment. Tumors were contoured
with CT/MRI fusion in all patients. Median tumor volume was 24,7 cm3 . Median collimator size was 12,5 mm. The dose was prescribed median 80%(72%-84%) isodose line. The tumor dose range was 15 Gy to 25 Gy in 1 to 5
fractions. Local control of tumors were defined as decrease in size (completeor partial), progression and stable disease by repeating MRI scan in 2 months
intervals. Treatment toxicity was determined according to WHO scores.
Results: Mean conformality and homojenity index values were 1,33 and 1,27
respectively. Mean tumor covarage was 95,8% and mean number of beam
used for irradiation was 198. 9 patients had no follow up. At the time ofanalysis, 31(86.1%) patients had died and 5 (13, 9%) were alive. Median survival after initial diagnosis was 19 months. Median survival after Cyberknife
treatment was 7 months. Median follow up was 8 months (4-23 months).
7 (19, 4%) patients had remission, 9(25%) patients had stable disease wasobserved in the first follow up. We observed progressive disease in 20 patients (55, 6%) within first follow-up. There was no WHO grade>2 side effect.
No acute grade 3-5 side effects were observed. No patient suffered acuteneurologic morbidity and no patient suffered seizures after treatment.
Conclusions: SRS is well tolerated in the treatment of GBM. Cyberknife
robotic radiotherapy may be useful for some selective cases to improve local
control and survival.
1525 poster
CYBERKNIFE STEREOTACTIC BODY RADIOTHERAPY FOR
OLIGOMETASTATIC LUNG TUMORS
G. Beltramo1 , A. Bergantin1 , A. Martinotti1 , P. Bonfanti1 , L. C. Bianchi1
1
C ENTRO D IAGNOSTICO I TALIANO, CyberKnife Center, Milan, Italy
Purpose: In patients with proven distant metatstases from solid tumors it has
been a notion that the mainstay of treatment is systemic therapy. However,in some patients, the metastatic disease may be very limited in number andsite and local aggressive therapy can potentially prolong survival. In a subset of patients with limited lung metastases we hypotesise that Cyberknife
Stereotactic Body Radiotherapy can improve treatments outcome.
Materials: between February 2007 to May 2010, 27 patients, 10 female, 17
male with a median age of 68 years (range 57 84 years) with 29 pathologically proven pulmonary metastases not amenable to surgery,(colorectal 10,
lung 9, Kidney 7, , pancreas 1, Breast 1, Parothyd 1) with a median grosstumor volume of 42.38 cc (range 3.55 240.06 cc) were referred to our Radiotherapy Department for Cyberknife stereotactic radiotherapy treatment. In all
patients 1-3 gold fiducials were implanted inside and or in the vicinity of tumor
for targetting purpose, except for patients who were eligible for fiducialless x
sight option. The planning treatment volume (PTV) included the GTV plus 5
mm isotropic margin, Total doses administered were 48-54 Gy in 3 to 4 fractions to the 75%-85% isodose line in patients with centrally located lesions,and 23 -27 Gy single fraction for peripheral lesions. Patients were followedwith CT and PET scan to detect disease recurrence Local recurrence wasdefined as an increase in size of tumor following treatment as most tumors
shrunk following radiation
Results: Median follow-up was 13 months (range, 443 months). KaplanMeier local control at 1 and 2 years was 89.1% and 89.1% respectively. We
observed an overall survival (OS) at 2 Years of 95.5% .Disease free Survival(DFS) at 1 and 2 years was 85.8% and 57.2% respectively
Conclusions: Cyberknife stereotactic radiotherapy, in patients with pulmonary metastases has been shown to be a promising treatment with highlocal control and low toxicity profile, but a longer follow up and a higher number of patients are mandatory to evaluate effectivenessS 568SRS-SBRT

SRS-SBRT

1526 poster
FLATTENING FILTER FREE BEAMS FOR LUNG AND SPINE SBRTW. Verbakel1 , C. L. Ong1 , J. Cuijpers1 , M. Dahele1 , B. Slotman1 , S. Senan1
VU U NIVERSITY M EDICAL C ENTER, Department of Radiation Oncology,
Amsterdam, Netherlands
1

Purpose: Treatment times for stereotactic body radiotherapy (SBRT) can belong, due to limitations in the maximum dose rate (typically ≤1000 MU/min).
However, flattening filter free (FFF) beams suitable for intensity modulated
SBRT have recently become available with dose rates up to 2400 MU/min.
We evaluated differences between treatment plans for stage I lung tumours
and spinal metastases using flattened and FFF beams, and compared measured with calculated dose distributions for FFF plans.
Materials: Five patients with peripheral lung tumours (PTV volume 11-50
cm3 ), treated with 3x18 Gy or 5x11 Gy (maximum dose 140%) using 6 MV
RapidArc (Varian) plans (maximum dose rate 1000MU/min) on the Novalis Tx(Tx) fitted with the HD-MLC (Varian, Brainlab) were replanned for the TrueBeam fitted with the Millennium MLC (Varian) using 10MV FFF (maximum
dose rate 2400MU/min). Optimization parameters were the same as for theTx plans. Each plan pair was normalised to the same prescription dose (PD).
This was repeated in four patients treated for spinal metastases with 1x16Gy
or 3x9Gy using RapidArc plans that spared the spinal cord (PTV volume 83226 cm3 and PTV length 411.5 cm). We assessed dosimetric data for the
PTV and organs at risk, number of MU and delivery times. For 2 lung and2 spine plans, Gafchromic EBT2 film measurements were compared to calculated dose in order to evaluate the dosimetric accuracy of FFF RapidArc
plans. Gamma evaluations with 3% for dose and 2 mm distance to agreement were used for the comparison.
Results: Average differences in lung plan PTV doses (mean, min, max) were<1% between Tx and FFF plans. Conformity index for PD and 75% of PD
were the same. Volumes of the thoracic wall receiving 40 Gy or 30 Gy were
6% higher for the FFF plans. FFF plans required on average 5% more MU,
but he average beam-on time was reduced from 3.9 to 2.5 minutes.Average
differences in spine plan PTV doses (mean, max) were respectively 1.5 and3.7% higher for the FFF plans. The dose to the spinal cord and its PRV
were 1% and 6% lower for FFF plans. FFF plans required on average 6%
fewer MU, and beam-on times were reduced from 6.7 (range 3.7 10.7) to 2.8(range 2.5 3.2) minutes. Where the Tx plans needed 3 arcs, FFF plans only
required 2.Measurements for all FFF plans agreed well with the calculated
dose (Eclipse planning system, Varian). Average gamma was 0.3 and thefilm surface with gamma>1 was on average 1%.
Conclusions: RapidArc plans for lung and spine SBRT using FFF beams
show similar plan quality to those with flattened beams, for PTV length up to
11.5 cm. The main advantage of the FFF plans is the reduced treatment timeand need for only 2 arcs. An 8050 MU, 1x16 Gy treatment plan for spinal
metastases which limits the spinal cord to <9 Gy required only 3.2 minutes
beam on time. These shorter treatment times using FFF may help to reduce
the risk of intrafraction motion.
1527 poster
HYPOFRACTIONATED STEREOTACITC BODY RADIOTHERAPYFOR LOCALIZED PROSTATE CANCER
G. Beltramo1 , A. Bergantin1 , A. Martinotti1 , F. Locatelli1 , P. Bonfanti1 , L. C.
Bianchi1
1
C ENTRO D IAGNOSTICO I TALIANO, CyberKnife Center, Milan, Italy
Purpose: Recent technological developments, intensity modulation radiation
therapy and improved target localization, combined with new hypothesis on
prostate radiobiology have generated enthusiasm for hypofractionated regimens. We report our early preliminary experience with Cyberknife stereotactic radiotherapy in patients with clinically localized prostate cancer
Materials: Between July 2007 and September 2010, 73 patients with a median age of 74 years (range 60 86) ,with T1c T2 b prostate cancer weretreated with Cyberknife stereotactic radiosurgery as primary therapy at our
institution. The majority of patients, 42, had Gleason Score 6, 23 patients
had Gleason Score 7, and 8 Gleason Score 8. Pretreatment PSAs ranged
from 1.75 to 19 ng.ml (median 8.01 ng.ml) The treatment regimen consistsof a total dose of 38 Gy delivered at 9.5 Gy per fraction, over 4 consecutive
days, with > 95% of the PTV encompassed within the prescription isodose
volumeBetween July 2007 and September 2010, 73 patients with a medianage of 74 years (range 60 86) ,with T1c T2 b prostate cancer were treatedwith Cyberknife stereotactic radiosurgery as primary therapy at our institution. The majority of patients, 42, had Gleason Score 6, 23 GS 7, and 8 GS
8. Pretreatment PSAs ranged from 1.75 to 19 ng/ml (median 8.01 ng.ml) The
treatment regimen consists of a total dose of 38 Gy delivered at 9.5 Gy per
fraction, over 4 consecutive days, with > 95% of the PTV encompassed within
the prescription isodose volume.Three gold fiducial markers were placed in
prostate gland. Treatment planning was done with CT scan fused with Mri inall patients does was prescribed to the 80% isodose line, with 5 mm beyond
the capsule, except posteriorly were the margin was 3 mm. Patients wereseen in follow up 10 days post-treatment, 1 month later and every 3 months
for 3 years with PSA levels assessed at each follow up. Self administeredquestionnaire, such as the IPSS and the IIEF , was used to better define urinary function and sexual activities. Toxicity analyses was performed using
RTOG-EORTC morbidity scoring system
Results: Acute side effects were generally mild and resolved shortly. No
RTOG grade 4 acute or late rectal/urinary complications was observed. In
one patient we registered grade 3 late rectal toxicy All patients were placedon A-blockade medication at the beginning of Cyberknife treatment. IPSS
scores increased over the first month of treatment but return to baseline byfour months. Three patients, one with prior Turp, experienced incontinence,
two 12 months after the treatment, one 27 months later. One patient experienced rectal incontinence 12 months after the treatment. The median follow
up was 15 months The patterns of Psa response, show a gradual declinewith a psa nadir below 1.0 ng.ml after 12 months. To date all patients arealive, Two high risk group patients failed biochemically. One developed bonemetastases, in one we observed pelvic lympn node involvmen
Conclusions: Early clinical results are encouraging and we conclude that
Cyberknife robotic radiosurgery is a feasible and an emerging non invasive treatment approach to deliver Hypofractionated radiotherapy for localized prostate cancer. Additional follow up is required to see if this results are
durable1528 poster
IMPLEMENTATION OF STEREOTACTIC BODY RADIOTHERAPY(SBRT) FOR NON SMALL CELL LUNG CANCERS IN THE UK:
UPDATE FROM THE SBRT CONSORTIUM
M. Hatton1 , K. Franks2 , P. Jain3 , D. Landau4 , N. Mohammed5
1
W ESTON PARK H OSPITAL, Sheffield, United Kingdom
2
S T J AMES I NSTITUTE OF O NCOLOGY T HE L EEDS T EACHING H OSPITALSNHS T RUST, Leeds, United Kingdom
3
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Bebington, Merseyside, United
Kingdom
4
G UY ’ S AND S T.T HOMAS ’ H OSPITAL NHS F OUNDATION T RUST, Department
for Radiation Oncology - section Quantitative Magnetic Resonance Imaging,
London, United Kingdom
5
T HE B EATSON W EST OF S COTLAND C ANCER C ENTRE, Department for
Radiation Oncology - section Quantitative Magnetic Resonance Imaging,
Glasgow, United Kingdom
Purpose: In early non-small cell lung cancer (NSCLC) there is now considerable non-randomised evidence supporting SBRT as superior to conventional
RT with respect to local control and as a possible alternative to surgery in highrisk surgical patients [1]. In 2007 a number of UK centres started to develop
SBRT programs. A literature search at this point highlighted heterogeneity inevery aspect of SBRT from patient selection to treatment delivery.
Materials: The UK SBRT Consortium was formed in 2008 to facilitate thedevelopment of SBRT in the UK to ensure a uniform standard of treatment
delivery across the UK. It represents an educational forum for members of themultidisciplinary team involved in SBRT and has developed national guidanceon patient selection, treatment planning/delivery and Quality Assurance forearly, medically inoperable lung cancers.
Results: The consortium has expanded rapidly with over 125 members in 34
UK centres and is performing annual national surveys to assess baseline andcurrent levels of activity with in the UK. Consortium guidance in early NSCLC
patients has been produced and highlights the basic principles of SBRT andspecifies minimum/gold standards from which individual centres can develop
site/equipment and departmental specific protocols. Quality Assurance guidance has been developed and the Consortium is actively developing a national research program for SBRT in NSCLC and will be producing guidance
for SBRT treatment of other tumour sites/types. To date over 100 lung cancer
patients have been treated at 8 UK centres; the patient demographics andUK survey results will be presented.
Conclusions: UK patients now have access to SBRT with 14 active treatment centres expected by the end of 2011. The consortium represents a
unique multidisciplinary, multi-centre approach to the introduction of a complex radiotherapy technology and is keen to continue its development.
1529 poster
PATIENT STABILITY DURING STEREOTACTIC BODY RADIOTHERAPY (SBRT) DELIVERED WITHOUT EXTERNAL IMMOBILIZATION
M. Dahele1 , W. Verbakel1 , B. Slotman1 , S. Senan1
1
VU U NIVERSITY M EDICAL C ENTER, Department of Radiation Oncology,
Amsterdam, Netherlands
Purpose: It is necessary to limit intra-fraction patient motion during highprecision SBRT. Some institutions use near-rigid external immobilization but
our approach emphasizes simplicity, patient comfort, frequent on-line imaging
and rapid SBRT delivery with no external immobilization for the vast majorityof patients. We report the stability of the vertebral column during lung SBRT
without external immobilization.
Materials: Imaging data from patients receiving risk-adapted lung SBRT for
early-stage lung cancer was analyzed. Stereoscopic X-rays (ExacTrac, Brain-

LAB) of the spine before and after each fraction were compared in 3 translational (vertical, longitudinal and lateral) and 3 rotational (rotation, roll andpitch) directions, in order to determine intra-fraction spine motion. Patientslie supine on a thin mattress with arms supported above their head (Posirest,
Sinmed) and a knee support. They are treated during free breathing using
2-volumetric arcs (RapidArc, Varian) delivered at 1000mU/min. Target localization uses on-line tumor match between the average intensity projection
planning CT and CBCT. The beam-on time is generally less than 6 minutes.
Results: A total of 109 SBRT fractions from 30 patients (23M and 7F, medianage 72yrs, range 38-90, 3x18Gy n=6, 5x11Gy n=8, 8x7.5Gy n=11, 12x5Gyn=5) were analyzed (median 4 fractions/patient, range 1-8). Mean time to deliver the prescribed fraction was 4.1 minutes (SD 1.3, range 2.95-10.05). 302
out of 327 (92.3%) translational and 317 out of 327 (96.9%) rotational datapairs differed by </=1mm and </=1 degree, 98.2% and 99.1% by </=1.5mm
and </=1.5 degrees and 99.7% and 99.7% by </=2mm and </=2 degrees,
respectively. Mean absolute motion (without distinguishing between +/-) invertical, longitudinal and lateral directions was 0.3mm (SD 0.3), 0.4mm (0.4)
and 0.5mm (0.5) respectively. Maximum motion in any direction was 2.8mm
and 2.3 degrees. 91/109 (83.5%) fractions were delivered with </=1mm translation and 102/109 (93.6%) with </=1 degree of rotation in any direction, and94.5% and 98.2% with </=1.5mm translation and </=1.5 degrees of rotation.
3 patients accounted for 12/18 fractions with >1mm and 5/6 fractions with
>1.5mm translational motion. Little correlation was observed between time
to deliver the prescribed fraction and vertical, longitudinal and lateral motion(R2 between 0.04-0.11).
Conclusions: These data demonstrate similar positional stability to that reported with near rigid immobilization. Our set-up is effective, patient-friendly
and avoids additional costs. Future strategies to further refine SBRT delivery
will include the identification of patients prone to motion and the developmentof treatment-specific imaging protocols.
1530 poster
PATIENTS QA FOR STEREOTACTIC RADIOSURGERY WITH HELICAL TOMOTHERAPY
M. Gusinu1 , S. Barra2 , G. Taccini1
1
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Medical Physics,
Genova, Italy
2
I STITUTO N AZIONALE PER LA R ICERCA SUL C ANCRO, Radiation Oncology, Genova, Italy
Purpose: This work’s purpose is to verify the techniques used in our center(Istituto Nazionale per la Ricerca sul Cancro, Genova) for quality assurance(QA) of single patient’s treatment with Helical tomotherapy (HT) in the caseof stereotactic radiosurgery (SRS).
Materials: At This moment in our center we have performed SRS treatment
on 3 patients with a prescription dose of 20 Gy and we are going to treat
another 4 soon.In order to assure the correct positioning of the patient weused a stereotactic frame from Radionics (INTER-FIX) suited for HT. For theplanning we used 3-Tesla magnetic resonance images, without the stereotactic frame, for the contouring of the target and CT images, with the frame,
for the positioning of the patient and the dose calculation.So, we started withusing our common techniques of QA for HT patients on SRS plan.For every
patient we prepare a verification plan using the Tomoteraphy’s treatment planning system (TPS), using the cheese-phantom, that is the standard with HT.
We have positioned the phantom in order to have the insert for the ionizationchamber in the center of the high dose zone, within the PTV zone. For thistype of QA we normally used the ionization chamber A1SL (volume: 0.056
cm3 ), and in this case we always checked that the active volume was always
within the high dose volume.Moreover in the same phantom we have inserted
a gafcromic film on the coronal axis. The verification plan is rescaled from 20
Gy to 2 Gy and 5 Gy, in order to work in the right interval of doses for the film
calibration.
Results: Measurements with ionization chamber have been found good
agreement. In all analyzed patients we found a maximum difference ofquite 3 percent, both 5 Gy plans (+2.03%;+1.36%;+2.00%) and 2 Gy plans(0.26%;+0.64%;+3.34%). With regard to film analysis we initially used thesoftware implemented on the Tomo TPS. This tool allows us to perform a verification check on the qualitative correspondence of the dose between film
and TPS, and allows us to visualize the gamma-index distribution.To obtaina quantitative answer we exported the dose plane from Tomo TPS after thematching with the film, and we have compared the film dose and the doseplane using the software Verisoft. With this software we have to make a newsemiautomatic matching between the two doses distribution. The analysis
with this software, however, observed a good agreement in terms of Gammaindex (3%-3mm) in an area of 48 cm2 around the high dose zone. The number of points that pass the test is 94.2%; 86.83%.99.6% for 5Gy plans and
90.3%, 97.3%, 96.6% for 2Gy plans.
Conclusions: Verification using ionization chamber is still usable and reliable unless the PTV volume is not too small compared to chamber volume,
but especially in the case of SRS we have to run a setup very precisely.The
measures with gafcromic are still comparable with those for other patients
TOMO.Next improvement will be the use of diode detectors in comparison
with the ionization chamber in order to obtain a greater number of reference
points.

S 569

1531 poster
RADIOSURGERY TREATMENT PLANNING–PROTOCOLS IN USE
AND QUALITY CONTROL METRICS IN TWO EUROPEAN CENTERS
R. De Sá1 , N. Teixeira2 , A. Pascoal1 , M. Aznar3 , I. Cardoso4 , A. R.
Coutinho5 , M. S. B. Pontes4 , C. Borges4
1
T HE C ATHOLIC U NIVERSITY OF P ORTUGAL, Biomedical Engineering,
Lisbon, Portugal
2
E SCOLA S UPERIOR DE T ECNOLOGIA, Lisboa, Portugal
3
T HE F INSEN C ENTER - R IGSHOSPITALET, Copenhagen, Denmark
4
M EDICAL C ONSULT, Lisboa, Portugal
5
M EDICAL C ONSULT C OMPANY, Lisboa, Portugal
Purpose: Stereotactic Radiosurgery (SRS) is an established alternative forthe treatment of brain tumors. Like other radiation treatments, SRS also involves risks, and adverse side effects can occur due to irradiation of healthy
tissues, or tumor control is not achieved. Therefore, when planning a SRS
treatment, the main goals to achieve are the maximum conformation of thereference isodose to the target volume, and minimum irradiation of adjacentnormal non-target tissues. Resulting real plan is affected by target characteristics (e.g. size, location) and aimed treatment goals, alongside technicalsettings (e.g. # of arcs, dose, # of isocenters). The study proposes an analysis of the SRS treatment planning procedures in use in two European radiotherapy centers and a critical comparison of quality control indicators for thetreatment plan.
Materials: The study was retrospective, based on treatment plans produced
in 2010 for patients with brain metastasis. Procedures and data from a totalof 86 treatment plans were analyzed. Data was collected in two radiotherapy centers (one in Lisbon/Portugal and one in Copenhagen/Denmark) andcompared. Details on the treatment planning methods and techniques in use
were considered in addition to relevant data (prescribed dose, delivered dose,target volume, mnd min dose, OAR dose limits, OAR) retrieved from the TPS.
Equipment in use was 2300CD Trilogy (Varian Medical Systems, Inc., Palo
Alto, CA)/ BrainLab’s iPlan (center A) and Novalis TX (Brainlab and Varian
Medical Systems)/ BrainLab’s iPlan (Center B). Established quality control
metrics for assessing the quality of the treatment plan were calculated: conformity index, CI=VRI/TV, and homogeneity index HI=Imax/RI, where TV is
the target volume, VRI is the volume receiving the reference isodose, Imax isthe max dose on target and RI is the reference isodose.
Results: Noticeable differences were found in the methods adopted for thetreatment planning in the two centers. In center B, 3 alternative techniques
are used while in center A the same technique is used for treating all brain
metastasis. Reference isodoses for prescription were 80%/PTV (center A)
and 90%/GTV (center B). Noticeable variability in the dose range prescribedfor various treatments was found in center. Dose limits adopted for the brainstem OAR varied between the centers. A preliminary comparison of averagetumor volumes for considered for the two centers showed no statistical differences (p-value=0,9816).
Conclusions: Despite the similarity between target volumes in the two centers, the Calculation of CI and HI showed relevant differences. A detailed
analysis of the relative positions of the target volume and OAR in ongoing.
Further details and conclusions will be presented and discussed.
1532 poster
RADIOSURGERY TREATMENTS AT LISBON GAMMA KNIFE CENTER: METASTASIS VS AVMS
S. Ikbal12 , L. Madureira12 , A. L. Luís12 , A. Rato12 , A. F. Soares12 , A.
Fernandes12 , M. J. Rosa12 , K. Jacob12 , B. Cattoni2 , J. Brás2 , J. Silva2 , N.
Teixeira3 , P. Ferreira45
1
M EDICAL C ONSULT, Lisboa, Portugal
2
C ENTRO G AMMA K NIFE , H OSPITAL C UF I NFANTE S ANTO, Lisboa, Portugal
3
EST E SL ISBOA -IPL / FCM EDICAL -UNL, Lisboa, Portugal
4
IPO L ISBOA, Lisboa, Portugal
5
EST E SL, Lisboa, Portugal
Purpose: The Leksell Gamma Knife Perfexion is the only system that focus
the targets defined in the brain with Co60 high precision radiation beams. The
Gamma Knife Center (CGK) in the Hospital Cuf Infante Santo is the only hospital in Portugal that has the Gamma Knife Perfexion from Elekta, which improves accuracy, reduces background radiation outside the treatment area,
reduces treatment times and can treat an expanded number of conditions.
The system comes complete with Leksell GammaPlan PFX, the dedicatedtreatment planning system designed to take full advantage of the featuresand intelligence incorporated in Leksell Gamma Knife Perfexion. Since 2007
more than 250 patients received the Gamma Knife treatment at the hospital, which means that more then 400 brain lesions were treated. The mostcommon pathologies treated at the CGK include Metastasis, Arterio-Venous
Malformation (AVM), Acoustic Schwannomas and other benign tumors. Oneof the main purposes of this study is to obtain reference values for Metastasis
and AVMs, which include the dose prescribed in each treatment planning, thePaddick Conformity Index (CI), the dose gradient index (GI), treatment timeand dose obtained in the organs at risk (OAR). Other of the main purposes is
to establish analysis criteria for the treatment planning, so we can correlateS 570SRS-SBRT

SRS-SBRT

the number of shots, the size of the shots, the treatment time and the doseprescribed with the target volume.
Materials: In this study an analysis was performed in all the Metastasis and
AVMs treatments done in the Leksell GammaPlan 8.3.1. The parameters
analyzed are the prescribed dose, prescribed isodose, the number of shots,
the CI, the GI, the volume of the lesions, the dose to OAR and treatment
time.Only volumes bigger than 0.5 cc were considered to calculate the GI
and the CI.
Results: For the AVM pathology the mean values are: prescribed dose is 20
Gy (range 14-25 Gy), isodose value is 51% (range 45-64%), treatment timeis 102 m (range 16-236 m), CI is 0.71 and the GI is 3.1. For volumes of 0.5
cc were used shots of 8 mm and for volumes above 1.7 cc were used shotsof 16mm. In AVM we used an average of 5 shots per cc.In the Metastasis
pathology case, the mean values are: the prescribed dose is 19 Gy (range
12.5-22 Gy), the isodose value is 64% (range 45-96%), treatment time is 30
m (range 7-150 m). In this pathology, for volumes above 1 cc were used shotsof 8 and 16 mm. In Metastasis we used an average of 3 shots per cc. The CI
is approximately 0.8 and the GI is 3.

total MU of 2500, the beam-on efficiency term ranged from 10.4 to 15.1 minusing the 6MV beam and 2.1 to 3.0 min using UF beam. The mechanicalmotion time (median 3.5 min) was around 2-5 min. The average abnormal
breathing time was <15% and >20% when the total treatment time was <5or >20 min, increasing with increasing delivery time. For median MU andmechanical motion, the abnormal breathing time was 3.3-4.5 min and 1.0-1.2
min using 6MV and UF beam respectively. Total times of 17.2-23.1 min and6.7-7.8 min were required using the 6MV and UF beam respectively; time
reduction ranged from 61.4% to 66.4% when the duty cycle was least.

95%of the PTV encompassed within the prescription isodose volume Patientswere followed with CT and PET scan to detect disease recurrence Local recurrence was defined as an increase in size of tumor following treatment as
most tumors shrunk following radiation
Results: Median follow-up was 19 months (range, 448 months). KaplanMeier local control at 1 and 2 years was 84.9% and 84.9% respectively, overall
survival (OS) at 1 and 2 years was 89.8% and 83.4% ,disease free Survival(DFS) at 1 and 2 years was 84.9% and 78%. We detected a late radiationinduced local fibrosis using CT imaging in most patients, but, till today, noneof patients had any chronic symptoms
Conclusions: These ppreliminary results suggest that CyberKnife-based
SRT is a feasible approach for primary lung cancer, offering excellent in-field
tumor control and low toxicity profile.Oowever more experience and a longer
follow-up are necessary to determine the role of CK and to identify patientsmost likely to benefit from it

S 571

the plan features thus guiding radiation oncologists in the choice of the bestplan.
Materials: Between December 2008 and June 2009 we processed for thisanalysis forty-five hypofractionated stereotactic radiotherapy treatment plans
for fifteen consecutive patients affected by brain metastases. Three rival
treatment plans were processed for each patient using BrainSCAN 5.31 software (BrainLAB) and three different delivery techniques: eight conformal fixed
fields, five non-coplanar static arcs and a single static arc. CI, HI and DG were
calculated for each plan (CVI was always one because of our dose prescription). We elaborated a formula to take into account the information given by
the above simple dosimetric indices. FORMULAwhere "∆xi" is the difference
between the value of each index and its ideal value of one, "n" is the numberof the simple indices taken into consideration (n=3 in our study) and "Ki" is aweighting factor. For each plan we calculated DI as well.

1535 poster
STEREOTACTIC RADIOTHERAPY AND RADIOSURGERY FOR
LUNG TUMOURS AND METASTASES
G. Spagnoletti1 , D. Di Gennaro2 , I. Pilotti2 , G. De Nobili1 , M. Piombino3 , G.
Bove1
A ZIENDA OSPEDALIERO - UNIVERSITARIA “O SPEDALI R IUNITI ", Struttura
Complessa di Radioterapia, Foggia, Italy
2
O SPEDALE U NIVERSITARIO, Radioterapia, Salerno, Italy
3
P OLICLINICO, U.O. Radioterapia, Bari, Italy
1

Conclusions: We conclude that the restrictions in terms of CI and GI must be
defined in terms of pathology and not in a general base.It’s difficult to estimate
the time of treatment for the AVM due to its irregular shape, so it’s also harderto define the target volume. These parameters are easier to estimate forMetastasis due to their regular shape and the use of fewer shots per cc.
We also conclude that despite the fact that these two pathologies are quite
different, normally we have the same prescribed dose.
1533 poster
REDUCTION OF TREATMENT TIME IN CLINICAL SBRT DELIVEREDWITH UNFLATTENED PHOTON BEAM
Y. Huang1 , R. Flynn1 , A. Siochi1 , J. Bayouth1
1
U NIVERSITY OF I OWA H OSPITAL AND CLINICS, Department of Radiation
Oncology, Iowa City, USA

Purpose: To evaluate the temporal advantage of using unflattened (UF) photon beam in clinical SBRT cases and present a method to predict the delivery
time for decision making on the use of UF beam.
Materials: Clinical data of 33 SBRT patients (130 fractions) treated with UF
6MV photon beam at 1500MU/min were reviewed. The delivery time was
retrieved from the patient data base and normalized to 10Gy/fx. These
were compared to the delivery time of 118 SBRT patients (383 fractions)
treated with a conventional 6MV beam (300MU/min) or a 10/18MV beam
(500MU/min) Fixed and gated treatments were compared separately. An empirical model to predict the delivery time for gated treatments was developed.
The total treatment time was calculated as the sum of three terms: a beam-on
efficiency term and two requiring beam-off (mechanical motion time and abnormal breathing time). Correlation between the temporal and %amplitudebased width of duty cycle was established to predict the beam-on efficiency
time, together with the total MUs, dose rate, average respiratory period andduty cycle: tefficiency=(MUtot/MUrate)*(Tperiod/Tduty). The mechanical motion time can be evaluated based on the # of beams, control points, and gantry
and MLC motion speed. The percentage of overall time experiencing abnormal breathing was computed and modeled as a function of total treatment
time. Quality assurance measurements were analyzed for all UF cases.
Results: Dosimetric agreement between plan and measurement with ion
chambers (1.00±0.02) and 2D film (passing Γ of 3%/3mm) was excellent
in all cases. Mean treatment times are shown in Figure 1. The overall
time reduction was about 36%(Liver) and 39%(Lung) in fixed and 64%(Liver)and 45%(Lung) in gated delivery with the UF beam. Gated liver treatments
showed the greatest reduction, from 19.6 to 7.0 minutes. The temporal duty
cycle for various gating window settings was shown in Figure 1. For a medianConclusions: Substantial time reduction was observed when using the UF
beam clinically in SBRT treatment. Our model enabled evaluation of eachcomponent of gated SBRT treatment time. In addition to total treatment time
reduction from higher dose rates requiring fewer respiratory cycles, the percent of abnormal breathing time was lower as well.
1534 poster
STEREOTACTIC BODY ABLATIVE RADIOTHERAPY FOR STAGE I
NON SMALL CELL LUNG CANCER
G. Beltramo1 , A. Bergantin1 , A. Martinotti1 , P. Bonfanti1 , L. C. bianchi1
1
C ENTRO D IAGNOSTICO I TALIANO, CyberKnife Center, Milan, Italy
Purpose: Although surgical resection remains the standard of care for patients with early stage non-small cell lung cancer (NSCLC), unfortunately,some patients are unable to tolerate the rigors of pulmonary resection.
Stereotactic body radiotherapy has emerged as one of new terapeuthic option.We evaluate the efficacy and feasibility of Cyberknife image-guide stereotactic body radiation therapy in patients with early-stage (Stage IA IB) non
small cell lung cancer (NSCLC)
Materials: between April 2006 to April 2010 ,34 patients, 2 female 32 malewith a median age of 74 years (range 55 89 years) with pathologically proven
NSCLC (squamous cell carcinoma, adenocarcinoma, large-cell carcinoma,
bronchoalveolar cell carcinoma, or NSCLC not otherwise specified), diagnosed as 16 stage IA and 18 Stage Ib were referred to our Radiotherapy
Department for Cyberknife stereotactic radiotherapy treatment. Before study
enrollment, patients underwent physicalexamination, computed tomography(CT) of the chest and upper abdomen,pulmonary function testing, and wholebody 18F-fluorodeoxyglucose positron emission tomography (PET)/CT fusion
study. In all patients one or three gold fiducial seeds were implanted in or
next to the lung cancer and to allow fiducials stabilization CT simulation was
performed one week later. Multiplan (version 2.0.5, Accuray, USA) was employed. The planning treatment volume (PTV) included the GTV expanded by
5 mm isotropic margin CK stereotactic radiosurgery protocol provide a prescribed PTV dose of 45 60 Gy given in 3 daily fractions of 15 20 Gy, with >Purpose: Radiosurgery is largely approved in the clinical course of oncologic
patients, when affected by primitive lung tumours or few (1-3) lung metastases
from other sites. This study reports three years experience in Stereo Body
Radiotherapy (SBRT) and Stereo Body Radiosurgery (SBRS) conducted by
two General Radiotherapy Departments.
Materials: Patients had Karnofsky Status > 80, primitive/metastatic lung tumors, diameter < 4 cm and were unsuitable for surgery. Since the beginning,
patients were treated with 3-6 fractions (Stereotactic Radiotherapy SBRT),
while in 2008 we decided for logistic reasons to use also a single fraction(Radiosurgery - SBRS) following the experience made by other centers inGermany and Japan, for lesions that were 2 cm afar from mediastinum. We
used a BRAINLAB Micro-multileaf and a body immobilization device; Radiological Physics Center (RPC) at the MD Anderson Cancer Center, Houston,
Texas, made the external monitoring of photon beams dosimetry.
Results: We have treated 23 patients with a minimum follow-up of 6 months(range: 6-27 months; mean: 15 months). The CTVs varied from 1.37 to 27.48
ccm. The CTV PTV margin expansion was 5-8 mm in antero-posterior andlatero-lateral direction and 10-13 mm in cranio-caudal direction. Patients were
irradiated with 9-19 coplanar or 8-12 non-coplanar fields. Radiation dose
was prescribed to the peripheral isodose of 80%. Five metastatic lesions
received 36-37.5 Gy in 3 fractions, 2 primitive tumours received 50 Gy in 5
fractions, 2 lesions in the immediate proximity of mediastinal vessels (<3 cm)
received 42 Gy in 6 fractions. Otherwise, 10 patients were treated with asingle fraction of 26 Gy in 8 cases and of 27 Gy and 18 Gy in the remaining
2 cases. Moreover SBRT or SBRS was used as boost technique to treat 4
patients, 3 T3N1 cancer and 1 sarcoma metastasis, diameter 5 cm. Twentytwo lesions were controlled, until now (96% local control). The only local
progression was observed on the first patient,treated for a metastasis, butwith the primary tumour still present. There were no acute or late clinicalcomplications. In 3 patients CT examination revealed radiological signs ofradiotherapy pneumonitis after 6-8 months. Two patients went to surgery
and the histological examination revealed no tumour in the >100 Gy (BED10)
treated volume.
Conclusions: In our first experiences Stereotactic Body Radiotherapy / Radiosurgery is a safe and practical option to treat lung tumours.
1536 poster
THE APPLICATION OF A DIFFERENTIAL INDEX TO GUIDE THE
CHOICE AMONG RIVAL PLANS IN STEREOTACTIC RADIOTHERAPY
G. De Nobili1 , G. Spagnoletti1 , M. Piombino2 , G. Plotino1 , G. Bove1
1
A ZIENDA OSPEDALIERO - UNIVERSITARIA “O SPEDALI R IUNITI ”, Struttura
Complessa di Radioterapia, Foggia, Italy
2
P OLICLINICO, U.O. Radioterapia, Bari, Italy
Purpose: In assessing the quality of a treatment plan and choosing among
rival plans, radiation oncologists can use a variety of dosimetric information:in addition to dose-volume histograms and isodose curves, there are dosimetric indices that move towards a quality-quantitative estimate of a treatment plan but often provide conflicting messages because they evaluate different aspects of dose distribution. Most frequently used dosimetric indices
are Conformity Index (CI), Homogeneity Index (HI), Dose Gradient (DG) and
Coverage Index (CVI). For an ideal treatment plan, the value of these indicesshould be one. The study aims to elaborate and assess the reliability of amultidimensional index, we called Differential Index (DI), in easly quantifying

Results: On the basis of the data we obtained we never found that the planwith the best value of an index had also the best values of other indices. Then
we noticed that in our series simple indices had a different order of magnitude.
So we used DI as a criterion of choice among competing plans, where thefactors Ki worked to equally weigh the contribution of each index. We called
this new parameter "differential index" because it expresses the difference
between the plan under consideration and the best ideal plan. The lower is
DI value, the better is the plan. Afterwards all values found for DI in each plan
were put in relation with the corresponding indices. Only CI and HI strongly
correlated with DI and between them (p<0,0001). Moreover DI showed astatistically significant correlation with other more complex indices proposedby literature. Retrospectively, basing on mean and standard deviation of the
DI values we obtained, we evaluated the quality of each plan.
Conclusions: CI confirms to be very helpful in a first and quick analysis of atreatment plan for stereotactic radiotherapy. Our study showed that Differential Index is a multidimensional and more reliable index. It summarizes in one
value the contribution of each dosimetric index and evaluates the extent towhich a plan achieves conformity, homogeneity, dose gradient and coverage
goals. Thanks to weighting coefficients, the DI formula could be adapted toexperience and aims of each Center, giving an equal or different importanceto simple indices. Moreover the suggested formula is open to all the existing dosimetric indices, if it is considered useful to include also more complex
ones. At last Differential index could be used to score and rank plans forstereotactic brain and body radiotherapy.
1537 poster
THE DEGREE OF CONSENSUS IN THE IMPLEMENTATION OF
STEREOTACTIC BODY RADIATION THERAPY IN EUROPE AND
AMERICA AND HOW THIS COMPARES TO A JAPANESE SURVEY
M. Mahon1 , M. Broderick1 , M. Coffey2
1
T RINITY C ENTRE FOR H EALTH S CIENCES, Discipline of Radiation Therapy,
School of Medicine, Dublin 8, Ireland Republic of2
T RINITY C ENTRE FOR H EALTH S CIENCES, Discipline of Radiation Therapy,
Dublin 8, Ireland Republic ofPurpose: Stereotactic Body Radiation Therapy (SBRT) has proven to be avery promising treatment method with results from phase I/II trials showing
excellent local control rates in a number of extra-cranial sites. However alack of consensus in the implementation of SBRT is observed in publishedliterature. The aim of this study is to determine the degree of consensus in
the implementation of SBRT clinically in America and Europe and compare
these findings to the current status of SBRT in Japan
Materials: Ethical approval was sought and granted from the Trinity College
Ethics Board, before this research project began. Participant information was
obtained through the 2009 ASTRO and 2003 ESTRO directories and contact
information from articles published in the area. An online questionnaire wasused for data collection. Approximately 1,000 emails were sent, with equalamounts sent to American and European Centres
Results: There was a response rate of 13.2%, with relatively similar responses from American and European participants. The result revealed that
there is a lack of consensus in immobilisation methods, DVCs, RCMs andfractionation schedules employed in the delivery of SBRT. Centres most commonly treat both primary and metastatic lung and liver cancer, use KV CBCTS 572T REATMENT PLANNING AND DOSE CALCULATIONSRS-SBRT

as a method of verification and have an inclusion criterion of ≤ 5cm whentreating these lesions.
Conclusions: The implementation of SBRT has wide variability in the published literature. Findings from this study indicate there is also variation in
its implementation clinically. American centres report following guidelines ofthe multi-institutional RTOG 0236 trial. American and European centres inthis study tended towards the use of large total doses in comparison to theresults of a Japanese survey.
1538 poster
THE DOSIMETRIC ADVANTAGE OF STEREOTACTIC RADIOTHERAPY IN PARTIAL BREAST IRRADIATION: A COMPARATIVEANALYSIS
Y. Mutaf1 , E. Nichols1 , C. Yu1 , K. Prado1 , S. Feigenberg1 , B. Yi1 , W.
D’Souza1 , W. Regine1
1
U NIVERSITY OF M ARYLAND S CHOOL OF M EDICINE, Department ofRadiation Oncology, Baltimore, MD, USA
Purpose: A dedicated stereotactic gamma irradiation device, GammaPodTM
from Xcision Medical Systems, has been specifically developed to treat breast
cancer. Dosimetric evaluation and clinical feasibility of this new technology isinvestigated through comparative treatment planning analysis to linac-based
3D-CRT and IMRT partial breast irradiation techniques.
Materials: The GammaPodTM device consists of a hemispherical source carrier containing 36 60 Co sources positioned along 6 columns in a non-coplanar
and iso-centric arrangement. The source carrier and variable size tungsten
collimator can deliver highly conformal dose distributions via rotation of the
combined assembly. A three-dimensional maneuverable patient positioning
system aligns the target with the focal point of radiation with the patient in
the prone position. The table also facilitates dynamic dose painting by moving through an optimized continuous trajectory during treatment delivery. A
stereotactic coordinate frame is established using a two-layered breast cup
immobilization device with built-in imaging fiducial markers. Dosimetric capabilities of this stereotactic breast irradiation device are investigated througha comparative treatment planning analysis performed retrospectively on 6
breast cancer patients. Following a partial breast planning strategy, we compared tumor bed coverage and the dose to the uninvolved breast tissue, lungand heart in the post-lumpectomy setting between GammaPodTM and linacbased 3D-CRT and IMRT.
Results: Figure 1 shows a large post-lumpectomy target volume (7 cm) situated close to the chest wall. Isodose lines achieved with the three treatment
plan designs implemented in this study are shown using 3D-CRT, IMRT and
GammaPodTM techniques. The intended target coverage was achieved in
all plans with varying degrees of dose conformity. The ratios of prescription
dose volume to PTV (conformity index) were 2.4, 1.8, and 1.4 while the 20%
isodose volume conformity indices were 9.5, 8.1, and 7.8 respectively for 3DCRT, IMRT and GammaPodTM treatment plans. The conformity advantage
observed in GammaPodTM plans also appeared as smaller doses to the uninvolved breast tissue; the ipsilateral breast V50% was 18.9% as compared
to 35.4% and 30.0% for 3D-CRT and IMRT plans. Heart and lung dosevolume histogram parameters were also improved with GammaPodTM planscompared to the other modalities.

tissue is required. In this study a retrospective analysis of the outcomes ofradiation therapy for patients treated for brain metastasis has been performed
in order to determine the values of the parameters of the model of tumour
control probability (TCP) that best fits the clinical data.
Materials: Fifty-three patients were treated using SRS and monitored bymagnetic resonance imaging and clinical observation. The treatment outcome was established according to the RTOG quality criteria; complete regression (CR), partial regression (PR) stable disease (SD) and progression
disease (PD). Due to the fact that the Spearman non-parametric rank test
showed a significant correlation (p<0.0001) with survival for both groups ofpatients classified CR and PR than CR, PR and SD, the fitting was performed
once considering that the tumor control was achieved only for those patientsclassified CR and PR and afterwards the patients classified SD were includedin the controlled group. The parameters TD50, gamma50 and alfa/beta of the
Poisson model for TCP were fitted using the maximum likelihood method andthe goodness of the fit was estimated.
Results: The value of gamma50 increases from 1.934 to 2.156 ua (11%)
when considering control diseases SD, CR and PR or PR and CR only for all
patients. In the subgroup of lung patients gamma50 increases from 1.946 to
2.438 ua when considering control diseases SD, CR and PR or CR and PR
only. The value of TD50 ranges from 37.44 to 39.17 Gy when considering
control diseases SD, CR and PR or CR and PR only for all patients. In thesubgroup of lung patients TD50 ranges from 33.30 to 28.91 Gy when considering as control disease SD, CR and PR or CR and PR only. The value ofalfa/beta is approximately 10 Gy with a 0.5 % variation between groups. In
all cases the chi2 resulted minor of the upper limit of chi2 for an acceptable
fit. The residuals appear randomly scattered around zero indicating that themodel describes the data well. The ROC curves used to compare the accuracy of two sets of data (observed and fitted) that are used to discriminate
cases of disease (PD or PD, SD) from healthy ones (SD, CR, PR or CR, PR)gave for each group an AUC value major of the cut off value of 0.5.
Conclusions: The results of this study indicate a high value of the α/β ratio
confirming that brain metastases behave as a fast repopulating tissue andthat this value does not depend on the primitive tumour.

Treatment planning and dose calculation
1540 poster
3D CONFORMAL VERSUS 2D RT: THE SPINAL CORD OR CAUDALATE DAMAGE PROBABILITY IN PALLIATIVE TREATMENTS
A. Terlizzi1 , D. Mola1 , P. Carmone1 , G. Laterza1 , G. Lazzari2 , G. Silvano2
1
ASL TARANTO, S.S. Fisica sanitaria, Taranto, Italy
2
ASL TARANTO, S.C. Radioterapia, Taranto, Italy
Purpose: The 2D RT hypofractionated radiotherapy plays a major role in
the palliation of bone metastases (BM) for practical reasons, but in palliative spinal bone radiation 2D conventional RT (single posterior field or AP PA
fields) doesn’t achieve good coverage of PTV and doesn’t consider dangerous hot spots on OAR’s as spinal cord, brachial plexus or cauda. We reportour results on dosimetric comparison for spinal cord dose in 2D vs 3D RT,
taking QUANTEC in account and using different photon energy.
Materials: Ten palliative treatments have been evaluated: seven vertebral
and three pelvis metastases. From a 3D conformal radiotherapy withmultiportal technique on CT scan the plan was converted by a 2D plan
(PA field in seven vertebral targets and two AP-PA opposite fields in threepelvis target). Hypofractionation was prescribed for all the patients: 40 Gy(2.5 Gy/16 fr in 1 pt); 30 Gy ( 3 Gy/10 fr in 4 pts); 20 Gy ( 4 Gy/5 fr in 5pts); 8 Gy (8 Gy/1 fr in 1 pt). The normalization point dose and the beam
weighting (for AP-PA opposed fields) were calculated to limit OAR’s hot spots
in the range of 100% - 105% although PTV coverage was poor. Different
dose distributions according photon energy (6 10 18 MV) where analyzed
too.DVH for target and spinal cord or cauda (OARs) were developed in
EQD2 in 3D and 2D plans respectively. According QUANTEC the α/β ratio
for spinal cord and cauda was 0.89 Gy. For spinal cord late damage weconsidered on DVH the maximum delivered dose to 1% of OAR volume.We
evaluated on spinal cord the occurrence of the "double trouble" phenomenon
converting the total maximal dose into the isoeffective maximal dose in 2 Gy
fractions, according to:

EQD2 = Dtotmax ((d + h)+α/β spinalcord )/(2+α/β spinalcord )(5)( h = hot spots per fraction)
Results: The table shows the results according 2D and 3D for each fractionation schedule.
For deeper target (cervical, dorsal spine) the double trouble effect was dependent by the photons energy used. Safe and effective treatment were thosedelivered with 10 and 18 MV photons.

Conclusions: GammaPodTM generated plans improved target conformity
and provided better dose fall off beyond the target volume suggesting a theoretical advantage that could lead to less morbidity and improved cosmesis ascompared to 3D-CRT or IMRT based partial breast irradiation.

Conclusions: The risk of double trouble effect appeared critical when low
doses / hypofractionation (2.5 3.0 Gy/fz) were used, because the probabilityof up 10% hot spots per each fraction during a large number of fractions
developed the fast rising of maximum cord dose with higher probability ofradiation myelitis. This effect is enhanced by the use of the lower photon
energies for deeper targets.QUANTEC analysis for spinal cord tolerance inpalliative hypofractionated radiotherapy is critical for spinal cord in 2D RT then
3D.

1539 poster

1541 poster

TUMOR CONTROL PROBABILITY IN STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES
V. Landoni1 , V. Pinzi2 , S. Gomellini2 , S. Arcangeli2 , K. Pasciuti1
1
I STITUTO R EGINA E LENA IFO, Department of Medical Physics, Rome, Italy
2
I STITUTO R EGINA E LENA IFO, Radiation Oncology, Rome, Italy

3D GAMMA EVALUATION USING A GRAPHICAL PROCESSING UNIT
(GPU)
L. Persoon1 , S. Nijsten1 , W. van Elmpt1 , F. Verhaegen1
1
D EPARTMENT OF R ADIATION O NCOLOGY (MAASTRO), GROW –S CHOOL FOR O NCOLOGY AND D EVELOPMENTAL B IOLOGY, M AASTRICHTU NIVERSITY M EDICAL C ENTRE , M AASTRICHT, THE N ETHERLANDS, maastricht, Netherlands

Purpose: Lung, breast, renal, colorectal and melanoma cancers are the mostcommon primary tumours for brain metastases and are often treated withstereotactic radio surgery (SRS). To ensure optimum use of this technique a
detailed set of information on the radiobiology of these tumours and normal

Purpose: The gamma (γ ) evaluation is widely used and accepted to quantify and evaluate differences in dose distributions. A major disadvantage of

S 573

the γ evaluation is that it is slow to compute, especially in 3D. The last few
years, many different approaches have been developed to reduce calculation
time. All these approaches are utilizing the computer’s central processing unit
(CPU). However, recently the graphical processing unit (GPU) has become apowerful platform for general purpose computing. In this study, we describe
the implementation of a 3D γ evaluation using a GPU to reduce calculation
time. Furthermore, we investigated the calculation accuracy of a CPU versus
GPU implementation for the γ evaluation.
Materials: A NVIDIA Tesla C2050 GPU unit was used and the γ evaluation algorithm was implemented using compute unified device architecture(CUDA) system development kit. Calculation times were scored and the accuracy of the GPU implementation was compared to the CPU implementation, using maximum and mean differences between both outputs (DIFFmax
and DIFFmean respectively). The differences were measured by a voxel-wisecomparison; DIFFmax is defined as the maximum relative difference, while
DIFFmean is the mean relative difference of all voxels. Firstly, various sized
cubical virtual phantoms were tested, introducing multiple types of artificial
dose-setup errors using γ criteria of 3% 3mm for all calculations. Secondly,
five patient cases have been evaluated comparing the 3D dose distribution
from the treatment planning system with the dose measured during treatment
as a comparison, to show clinical applicability.
Results: For the virtual phantoms, an average speed-up ratio GPU/CPU of
44±8 was achieved, ranging from 25 to 55 (see Figure 1a). The shortest calculation time for the GPU implementation was 0.01 s for the 1283 cube anddose-setup error of +1%/1mm compared to 0.25 s for the CPU. The longest
calculation time for the GPU was 0.39 s for the 3843 phantom and the largest
dose-setup error (5%/5mm) compared to 18.8 s for the CPU. DIFFmean andDIFFmax were negligible for all virtual phantoms. For the patient cases, anaverage speed-up ratio of 17±4 was achieved, ranging from 11 to 21. The
DIFFmean observed was smaller than 210-7 %, while DIFFmax did not exceed 3.110-4 %. A typical pattern of the difference between GPU and CPU isshown in Figure 1b.

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T REATMENT PLANNING AND DOSE CALCULATIONT REATMENT PLANNING AND DOSE CALCULATION

Conclusions: We showed that the calculation time for γ evaluations decreased considerably by using GPU technology without loss of accuracy. This
fast γ evaluation implementation can e.g. be used to achieve clinical acceptable calculation times in an adaptive dose delivery strategy where the delivered 3D dose of-the-day is compared to the planned dose.

Purpose: This report addresses uncertainties pertaining to brachytherapy
single-source dosimetry preceding clinical use. The International Organization for Standardization (ISO) Guide to the Expression of Uncertainty in
Measurement (GUM) and the National Institute of Standards and Technology(NIST) Technical Note 1297 are taken as reference standards for uncertainty
formalism. Uncertainties in using detectors to measure or utilizing Monte
Carlo methods to estimate brachytherapy dose distributions are provided withdiscussion of the components intrinsic to the overall dosimetric assessment.
Uncertainties provided are based on published observations and cited whenavailable. The uncertainty propagation from the primary calibration standard
through transfer to the clinic for air-kerma strength is covered first. Uncertainties in each of the brachytherapy dosimetry parameters of the TG-43 formalism are then explored, ending with transfer to the clinic and recommended
approaches. Dosimetric uncertainties during treatment delivery are considered briefly, but are not included in the detailed analysis.
Materials: Components of measurement uncertainty may be classified into
two types, namely those evaluated by statistical methods (Type A), and thoseevaluated by other means (Type B). In the past, Type A and Type B uncertainties were commonly referred to as random and systematic errors (more properly uncertainties), respectively. The use of the term error is discouraged in
uncertainty analyses since it implies a mistake, or refers to the difference between the measured value of a quantity and the true value, which is unknown.
For example, what might be considered as an error by one dosimetry investigator could be considered an uncertainty by another investigator. Specifically,
investigator 1 might assign a large uncertainty to the dimensions of internalsource components without having first-hand knowledge of source construction or the ability to open the capsule. Investigator 2 might question the values
used by investigator 1, considering them erroneous, having opened the capsule and measured the dimensions of the internal components. If the true
value was known, there would be no need to perform the measurement or
simulation.
Results: While lower uncertainties are clearly better, what maximum uncertainty should be clinically acceptable? Like the joint ABS/ACMP/ACRO report,
the AAPM and GEC-ESTRO also recommend actions be taken to reduce
the uncertainty of dose delivery for a particular patient implant such as applicator repositioning, written directive adjustment, or procedure termination.
However, the AAPM and GEC-ESTRO recognize that at this time the clinicalmedical physicist is unlikely to be able to accurately determine the dosimetric
uncertainties of multiple sources because no specific recommendations havebeen published. Clinical practice recommendations on the uncertainty of thedose deviation have not been previously provided. Dosimetric uncertainty
contributions that lead to an overall expanded uncertainty of less than 10% (k= 2) for conventional photon-emitting brachytherapy sources. Yet there may
be sources in which these dosimetric uncertainties are larger, such as whenusing investigational sources that lack a robust source-strength calibration
traceable to a primary standards laboratory, or for sources whose calibration
carries uncertainties larger than those examined herein due to design variations and subsequent energy differences. These circumstances and otherfactors may result in increased dosimetric uncertainties. When these uncertainties add to those for sources of Table V and exceed 20% (k = 2), thenthe AAPM and GEC-ESTRO recommend that brachytherapy implants be performed with caution preferably under institutional review board oversight withprior disclosure to the patient about the uncertain aspects of the procedure.
Conclusions: The AAPM and GEC-ESTRO have refined clinical expectations of brachytherapy dosimetric uncertainty. Uncertainties are involved in
all aspects of the dosimetry process. Every aspect of the process results ina greater uncertainty in the estimation of patient dose. When all these uncertainties are combined, the k = 2 uncertainty of dose rates for low- andhigh-energy photon-emitting brachytherapy sources used in treatment planning are approximately 8% and 6%, respectively. Uncertainty in dose delivery due to physical implantation will add to these uncertainties and surely belarger upon clinical implementation. Consequently, it is paramount that theclinical medical physicist be cognizant of these uncertainties and endeavor tominimize them for the aspects within their responsibilities.
1543 poster

1542 poster
A DOSIMETRIC UNCERTAINTY ANALYSIS FOR PHOTON-EMITTING
BRACHYTHERAPY SOURCES BY THE AAPM AND GEC-ESTRO
L. DeWerd1 , G. Ibbott2 , A. Meigooni3 , M. Mitch4 , M. Rivard5 , K. Stump6 , B.
Thomadsen7 , J. Venselaar8
1
U NIVERSITY OF W ISCONSIN , M ADISON, Medical Physics, Madison WI,USA
2
MD A NDERSON C ANCER C ENTER, Radiation Physics, Houston, USA
3
C OMPREHENSIVE C ANCER C ENTER OF N EVADA, -, Nevada, USA
4
NIST, Ionizing Radiation Standards, Gaithersburg, USA
5
T UFTS M EDICAL C ENTER, Radiation Oncology, Boston, USA
6
S ANTA M ARIA R ADIATION O NCOLOGY C ENTER, Radiation Oncology, Santa
Maria, USA
7
U NIVERSITY OF W ISCONSIN M EDICAL S CHOOL, Medical Physics, Madison,USA
8
D R . B ERNARD V ERBEETEN I NSTITUUT, Medical Physics and Engineering,
Tilburg, Netherlands

ABSOLUTE DOSE MEASUREMENTS AND TREATMENT PLANNING
SYSTEM PERFORMANCE TRENDS IN FINNISH CLINICS DURINGYEARS 2003 - 2010
J. Niemelä1 , P. Sipila1 , R. Bly1
1
R AD. AND N UCLEAR S AFETY AUTHORITY (STUK), Helsinki, Finland

deviation to output factor in TPS, or dose table (DT) in reference field. Monitor units (MU) are calculated by TPS with the goal to produce a 2 Gy dosein the center of the field at 10 cm depth with photons and at dose maximum
depth with electrons. We will also present TPS calculation performance in
non-reference fields including wedge and MLC fields as well as inhomogeneity correction.
Results: During six years (2003 2008) the absolute dose measurement in
Finnish clinics has been very accurate (compared to STUK measurement)
and reliable (Figures 1 and 2) with overall one standard deviation of 0.3 %and 0.8 % for photon and electron beams, respectively. Also with appropriate quality assurance the accelerator output is kept well in reference levels
that are input to TPS as output factors. Overall one standard deviation of accelerator dose output difference to dose table is 1.0 % and 1.3 % for photon
and electron beams, respectively. We will present the complete results during
2003 2010 together with TPS calculation performance.

Materials: CT dataset of ten patients presenting stage III NSCLC wereselected. All patients were contoured for PTV and organs at risk: lungs,
heart, spinal cord. Plans were created for 6MV beams from a Clinac 2100iX
equipped with MLC-120 Millennium. Three modalities were analysed:- 3DCRT: 4-5 fields, no-one entering from contralateral lung. MLC and wedges
were used whenever needed.- IMRT: 6 fields, no-one entering from contralateral lung.- RapidArc: 2 partial arcs, no-one entering from contralaterallung.Calculations were performed with Acuros XB version 11.0, and AAA version 10.0 with a dose calculation grid of 2.5mm. Acuros XB calculates thedose (to medium) accounting for the elemental composition of the patient,selecting the human tissue from predefined HU ranges. Acuros XB and AAAplans were computed with the same MU.To distinguish between differences
coming from the different management in heterogeneity, to those coming fromthe algorithm per se and its configuration, all the plans have been recalculated assigning to the patient outline of the CT dataset, the water material
with HU=0. To evaluate the Acuros XB algorithm also in terms of its clinical usability, the computation time was recorded for all plan calculations, andreported as ratio between calculation time for Acuros XB and AAA.
Results: Differences in dose distributions between the two algorithms in allcases with water material assignment were <0.5% of the prescribed dose asmean dose to target and OARs. This suggests to ascribe the differences
found in the real CT dataset to the different heterogeneity management, thatis in principle more accurate in the Acuros XB calculations. PTV dose difference was differentiated between the target in soft tissue, where the meandose was found lower of about 2% for Acuros XB, and the target in lung tissue,
where the mean dose was higher of about 1%. Mean doses to OARs did notpresent big differences, being of the order of 0.1-0.2% of the prescription. No
particular differences were found related to the various modalities.Calculation
time ratios were: 14 for 3D-CRT (mean Acuros XB calculation time 5’51" on a
Dell T5500 platform), 12 (mean Acuros XB 4’30") for IMRT, 0.5 (Mean Acuros
XB 6’26") for RapidArc.
Conclusions: Acuros XB showed differences in PTV dose calculations forlung cancer treatment with respect to AAA, that could be of clinical interest.
The new algorithm was twice as fast for RapidArc calculations, while AAAremains the fastest for 3D-CRT and IMRT.

Figure 1. Photon beams: average and one standard deviation of the difference of 1. absolute dose measured by the clinics and STUK and 2. accelerator output to dose table (DT).

1545 poster

Figure 2. Electron beams: average and one standard deviation of the difference of 1: absolute dose measured by the clinics and STUK and 2: accelerator output to dose table (DT).
Conclusions: Radiation and Safety Authority of Finland executes an inspection every second year to a linear accelerator in radiation therapy. This includes absolute dose measurements by the clinic and the authority, as wellas treatment planning calculation verifications. This has led to very reliable
and consistent absolute dose measurement in the clinics and a sound knowledge of the capabilities and draw backs of the treatment planning systems
used.
1544 poster

Purpose: In this study we show the accuracy and deviation of absolute dose
measurements and the performance of treatment planning systems (TPS) in
Finnish clinics during 2003 2010.
Materials: Data has been measured by the Finnish Radiation and Nuclear
Safety Authority (STUK) on site visits in hospitals. Measurements during
2003 2010 on over 35 linacs are included, comprising an average of about 14
linacs per year. Measurement of absolute absorbed dose in water is done bya farmer type ionization chamber for photons and by plane parallel chamber
for electrons using reference fields as defined in IAEA TRS No. 398. The accuracy of absolute dose measurement by a clinic is evaluated by comparison
to the measurement of the authority. We also evaluate the accelerator output

S 575

ADVANCED LUNG TREATMENT USING DIFFERENT MODALITIES:COMPARISON OF ACUROS XB AND AAA DOSE CALCULATIONS
A. Fogliata1 , A. Clivio1 , G. Nicolini1 , E. Vanetti de Palma1 , L. Cozzi1
1
O NCOLOGY I NSTITUTE OF S OUTHERN S WITZERLAND, Medical Physics,
Bellinzona, Switzerland

Purpose: Acuros XB is the new photon dose calculation algorithm implemented in the Varian Eclipse TPS, based on the solution of the Linear Boltzmann Transport Equation. Aim of the study was to assess the impact of using
the new algorithms in clinical cases.

ANALYSIS OF 10 MV ELEKTA PRECISE BEAM MODELLING DATAFOR THE COMPASS® DOSE CALCULATION AND VERIFICATIONSYSTEM FOR IMRT.
A. H. Ausma1 , M. Arends1 , M. Birkner2 , K. Visscher1
1
R ADIOTHERAPEUTIC I NSTITUTE F RIESLAND, Leeuwarden, Netherlands
2
IBA D OSIMETRY, Schwarzenbruck, Germany
Purpose: Validation of a pre-clinical version of Compass® for 10 MV photons.
It concerns the extension of the commercial released 6 MV model to otherenergies.
Materials: Compass® (IBA Dosimetry) is a 3D-QA system consisting of alinac head model from which the fluence phase space is calculated and acollapsed cone (CC) dose engine for the dose deposition. The predicted fluence can be corrected by 2D-detector array measurements (MatriXX, IBA
dosimetry) via dose reconstruction. Validation of the system consists of threephases. First step is the initial beam commissioning of a 10 MV Elekta Precise machine using the Linac head geometry specifications and measured
depth doses, profiles, output factors and dose per monitor unit calibration.
Second step is the fine tuning of the model parameters taking care of MLC
and jaw transmission and corrections regarding curved leaf tip and tongue
and groove effect. Parameter optimisations are based on comparison of predicted response with MatriXX measurements and treatment planning system(TPS) calculations. TPS benchmarking is performed with Oncentra Masterplan (OMP v3.3; Nucletron) with a pencil beam (PB) and CC-model. Third
step concerns the verification of computation and dose reconstruction using
tests of standard fields on phantoms evolving towards clinical prostate planson patient CT data. Comparison with measurements and OMP is basedon single points (ion chamber measurements) and 3D-gamma analysis (gcriteria 3%/2mm).
Results: An initial dose model was created with the auto modelling option.
Together with manual steering towards logical physical parameters (e.g. energy spectrum, source sizes, beam profile corrections and off axis softening), a good fit between measured input and Compass® computations wasachieved (global differences, i.e. relative to maximum dose, <1%). Then, response based fine tuning using MatriXX measurements improved MLC andjaw transmission calculations. By optimising parameters (which correct for
simplifications in the MLC model) using off axis fields and field abutments
to match OMP calculations, penumbra modelling has also been improved.
Regarding data comparison, Compass® computations agree well with measurements. For single fields (3x3 up to 30x30 cm2 ) single point computations(ssd = 90 cm, d = 10 cm) agree within 1%. Comparing a clinical composite
prostate plan to OMP-PB, as a typical example 99.8% of the PTV satisfied the
gamma criteria with an average gamma gavg = 0.62. Using the dose reconstruction, results improved to 99.9% of the PTV satisfying the gamma criteriawith gavg = 0.22. Although dose differences increased when Compass® computations were compared with OMP-CC calculations, this could be reduced
to a Compass® dose-to-water versus OMP dose-to-medium issue.

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T REATMENT PLANNING AND DOSE CALCULATIONT REATMENT PLANNING AND DOSE CALCULATION

Conclusions: The extension of the model to 10 MV photons yield computations that amply fulfils the accuracy needed for clinical introduction.

micrometrical scale. Dose distributions obtained from experimental measurements are most faithfully reproduced by the MC dose computation.

1546 poster

1548 poster

ATTENUATION OF CARBON FIBER TREATMENT COUCH AND
MANAGEMENT IN ECLIPSE TREATMENT PLANNING SYSTEM
S. Lozares1 , S. Pellejero1 , U. Iriondo1 , A. Forner1 , A. Otal1 , S. Miquelez1 ,F. Maneru1 , M. L. Martin-Albina1 , P. M. Soto1 , A. Rubio1
1
H OSPITAL DE N AVARRA, Servicio de Radiofísica y Protección Radiológica,
Pamplona, Spain

CBCT DOSE CALCULATION ACCURACY IN HEAD AND NECK
D. Emmens1
1
S UFFOLK O NCOLOGY C ENTRE T HE I PSWICH H OSPITAL NHS T, Department of Radiotherapy Physics, Ipswich Suffolk, United Kingdom

Purpose: Attenuation of carbon fiber treatment couch and management in
Eclipse treatment planning system
Materials: The dose perturbation at depth and in the dose build-up region
when treatment couch, Varian Exact Couch (Varian Inc. Palo Alto USA), wasplaced between a photon beam source 6 and 15 MV and the phantom wasmeasured. Beam attenuation was measured in the center of a cylindricalacrylic phantom with a PTW 0.125 cm3 type ion chamber at multiple gantry
angles. Dose build-up was measured in Solid Water with plane parallel ion
chambers with the beam normal to both the phantom and couch surfaces.
Both experiments were modelled in Eclipse (Varian Inc. Palo Alto USA). Dose
distributions calculated with AAA algorithm were compared to measurement.
The experiment evaluates the couch model that Eclipse implements in version
8.6 and later.
Results: We have determined that neglecting the attenuation of oblique treatment fields by the carbon fiber couch can result in localized strong dose reduction. The Exact Couch modelled in Eclipse has two values of density (CTnumber) for table and rails. After measurements these values have changed
in order to dose perturbations in patients from -300 to -500 in flat and from
200 to 400 in rails in CT number. Dose attenuation ranges between 2% to16%.
Conclusions: The presence of the couch structure between the patient andbeam source significantly alters dose in the patient. In certain angles thebeam may intersect the rails of the couch and the recommendation is to avoid
that situation, if not, these measurements are needed in order to adequate
Eclipse parameters of the couch.
1547 poster
BENCHMARKING OF A TREATMENT PLANNING SYSTEM MONTECARLO ENGINE FOR MICROBEAM RADIATION THERAPY
I. Martínez-Rovira1 2 , J. Sempau2 , A. Bravin1 , Y. Prezado1
1
E UROPEAN S YNCHROTRON R ADIATION FACILITY, Biomedical Beamline
ID17, Grenoble, France
2
U NIVERSITAT P OLITÈCNICA DE C ATALUNYA (UPC), Institut de Tècniques
Energètiques, Barcelona, Spain
Purpose: Microbeam Radiation Therapy (MRT) is a synchrotron radiotherapy
technique potentially used to treat gliomas. MRT explores the limits of thedose-volume effects by irradiating with an array of rectangular 50 µm-width
X-ray beams of 400 µm pitch. The preclinical MRT studies have successfully
shown that it is possible to ablate highly aggressive tumours in animals whilesparing the surrounding healthy tissue. The next step in the developmentof the MRT Project at the ID17 Biomedical Beamline (ESRF) is to prepare
the future clinical trials in pets as a milestone before the treatment of humanbeings. In this context, a dedicated Treatment Planning System (TPS) is
under development and benchmarking. This a very challenging project as nocommercial TPS has been developed for such small irradiation fields. The MC
engine for the MRT TPS includes the complete description of the synchrotron
source (X-ray energy spectrum, phase space and polarization) as well as thebeam transport through 42 m of optical elements up to the patient position,
where a Phase Space File (PSF) containing the state of all particles is saved.
This PSF is used as an input for the dose computation in a model of thepatient, reconstructed from Computed Tomography (CT) images.
Materials: The TPS is based on Monte Carlo (MC) simulations using the
PENELOPE/penEasy code. The calculations allow the decoupling of theCT image voxel grid (size in the order of mm3) to the dose bin grid, thathas micrometrical dimensions in the direction transversal to the microbeams.
Variance-reduction techniques and parallelisation methods (CONDOR) havebeen applied in order to speed up the planning process.The resultant MC
dose distributions have been benchmarked with experimental data by using
several detector systems (HD-810 Gafchromic Films, PTW Semiflex 31010
ionization chamber) in homogeneous media (water tank PTW MP3-P 41029,
PTW RW3 solid water slab phantom).
Results: Preliminary results on the comparison of measured Percentage
Depth Dose (PDD) curves and lateral dose profiles with respect to Monte
Carlo simulations for various field sizes will be presented. A good agreement
has been obtained.
Conclusions: The success of the Microbeam Radiation Therapy preclinicalstudies has opened the door to the future clinical trials. With this purpose,a dedicated MC engine for the MRT Treatment Planning System has beendeveloped and benchmarked. The TPS includes the dose computation at

Purpose: CBCT scans can show the dosimetric effect of changes in soft
tissue caused by weight loss, tumour shrinkage or tumour growth. The clinician uses this information to modify the patient’s treatment or inform theircare. Dose calculation accuracy depends on the fidelity of the Hounsfield
units (HUs). This work assesses the accuracy with which dose can be calculated on CBCTs of the head and neck.
Materials: An anthropomorphic phantom of the head and neck was CBCT
scanned on the Varian On-Board Imager. A planning CT scan of the phantom was also acquired. The CT scan was used to simulate treatment plans forthe ethmoid sinus and the oropharynx using rotational IMRT techniques. The
plans were recalculated on the CBCT scans with fixed monitor units. Comparisons between the CT and CBCT dose cubes were made using a three
dimensional gamma analysis.
Results: Agreement between the CT and CBCT dose cubes is between 1
to 2% in tomographic slices through the head. In the lower neck and shoulders the agreement is within 5%. At this level the CBCT HUs of soft tissue
are underestimated by up to 200 units. The agreement can be improved byoverriding the HU values.
Conclusions: Dose calculation accuracy on a CBCT of the head and neckvaries between 1 to 5%. It is worse in the neck and shoulders, where weightloss during a course of radiotherapy is most likely to occur. HU correction
strategies can be used to compensate for this. These strategies are applied inour centre to estimate the significance of weight loss in severe clinical cases.
1549 poster
CLINICAL IMPLICATIONS IN THE USE OF THE PBC ALGORITHM
VERSUS THE AAA BY COMPARISON OF DIFFERENT NTCPMODEL/PARAMETERS
A. Bufacchi1 , B. Nardiello1 , R. Capparella1 , L. Begnozzi1
1
O SPEDALE S AN G IOVANNI C ALIBITA FATEBENEFRATELLI, AFaR U.O. C.
Medical Physics, Rome, Italy
Purpose: Retrospective analysis of 3D clinical treatment plans to analyze
clinical implications in the use of the Pencil Beam Convolution (PBC) algorithm versus the Anisotropic Analytical Algorithm (AAA) via comparison ofdifferent normal tissue complication probability (NTCP) model/parameters fortreatments of the prostate, head-and-neck, breast, and lung.
Materials: The clinical treatment plans of 80 patients produced using the
PBC algorithm were recalculated using the AAA; the consequences of thedifference on the dose-effect relations for normal tissue injury were studied
by comparing different NTCP model/parameters extracted from a review ofpublished studies. The higher accuracy of the AAA is well established; in thisstudy the AAA dose calculation is considered as benchmark data.
Results: In the prostate plans, the AAA predicted lower NTCP value for therisk of late rectal bleeding for each of the eight combinations of NTCP parameters. In the head-and-neck treatments, each combination of parameters
used for the risk of xerostemia from irradiation of the parotid glands involved
lower NTCP when the AAA was used, and the differences were statisticallysignificant. The same result was obtained regarding the risk of radiation pneumonitis in the lung treatments for which eight sets of NTCP parameters wereconsidered. A markedly different pattern was observed for the risk relating to
the development of pneumonitis after breast treatments: the AAA predicted
higher NTCP value and the difference between the two algorithms was statistically significant. The mean NTCP varied from 0.12% (sd = 0.02%) to 2.13%(sd = 0.31%) according the combination of parameters used, while the useof the PBC algorithm resulted that NTCP varied from 0.08% (sd = 0.02%) to
1.78% (sd = 0.25%).
Conclusions: When the AAA was used, the poorer coverage of the target
was generally reflected in the lower TCP and NTCP, just as it was predictedby the application of different combinations of radiobiological parameters. Except for the breast treatments, for which the NTCP relating to the risk of development of pneumonitis was higher when the AAA was employed. The use of
the AAA in preference to the PBC is recommended for treatment planning inwhich low density tissue is present.However, prior to the adoption of the AAA
into clinical treatment planning practice, it is necessary to fully understandits effect and its potential consequences by re-evaluating an assessment of
dose-effect relationships and the parameters used in treatment planning decisions. This study also shows how the NTCP value is strongly affected by
the wide-ranging values of radiobiological parameters. Absolute NTCP values are not reliable enough to be considered for evaluating a treatment plan.
However, the NTCP values, along with the dose volume histograms (DVHs),
are a useful tool for comparing rival plans.

S 577

1550 poster
COMMISSIONING A FLATTENING FILTER FREE LINAC FOR A
TREATMENT PLANNING SYSTEM: CORRECTNESS AND ROBUSTNESS TESTING FOR PATIENT PLANNING.
K. Visscher1 , M. Arends1 , A. H. Ausma1
1
R ADIOTHERAPEUTIC I NSTITUTE F RIESLAND, Leeuwarden, Netherlands
Purpose: Validating the beam fit for a FFF linac in a commercial TPS and its
feasibility for patient planning.
Materials: From an Elekta Axesse linac (6 and 10MV) with Beam Modulator MLC the Flattening Filter (FF) was removed and replaced by a 6 mm Al
filter. The FFF energies were tuned to match the clinical FF beams (PDDof 9.6x10.4 cm2 field at d = 10 cm). The FFF machine was accepted withthe same set of specifications (when applicable) as a normal linac. For commissioning the TPS (Nucletron Oncentra External Beam 3.3 SP1) the normal
required set of PDDs, profiles, star profiles and output factors in air and water
were measured and sent to Nucletron for beam fitting. The resulting beam fit
can be optimized for focal spot size and measured inter leaf leakage by thecustomer in the Beam Modelling Tool. An extensive set of on-axis and off-axis
fields, ranging from 1.6x1.6 up to 21x16 cm2 , was used to verify the validityof the beam fit by comparing measured vs. calculated profiles and output
for the symmetric fields and a variety of (extremely) off-axis fields. To test
the robustness of the FFF beam fit for patient planning a prostate case wasused on which 4 plans were made: a FF-VMAT and FFF-VMAT plan with theisocentre located inside the PTV and a FF-VMAT and FFF-VMAT plan with
the isocentre of the beams shifted 5 cm laterally and 5 cm in height. Planevaluation was done using clinical evaluation criteria and DVH comparison.
Results: The profiles for the symmetric fields fitted better for FFF beams thanfor the FF beams. For FFF the fit quality improved with increasing field size.
For the off-axis field profiles the differences between FF and FFF were not significant, both FF and FFF beam fits were acceptable for clinical use. The output ratio (calculated/measured dose) for the symmetric beams from 3.2x3.2
cm2 and upwards lies between 0.98-1.00 for the Pencil Beam algorithm and0.99 - 1.01 for the Collapsed Cone algorithm, FFF being slightly worse thanFF. For the off-axis fields the mean error between calculated and measured
output is smaller for FFF than for FF (1.4±1.4% (1 SD) vs 2.0±1.2% (1 SD)).
The prostate plans for FF and FFF, both on-axis and off-axis, showed equalvalues for the DVH evaluation criteria.
Conclusions: FFF linacs can be modelled for a commercial TPS with adequate accuracy for routine clinical use. In general the FFF fits are slightly
better than for the FF linac. This confirms our expectations since removing
the Flattening Filter reduces the number of scattered electrons in the treatment head and makes the energy spectrum of the beam more homogeneousand consequently easier to model.
1551 poster
CONRES: CONFORMAL RECTUM SPARING 3D NON-COPLANARRADIOTHERAPY TREATMENT FOR PROSTATE CANCER AS AN
ALTERNATIVE TO IMRT
Z. Sebestyén1 , P. Kovacs1 , K. Sebestyen1 , R. Farkas1 , S. Bellyei1 , A.
Szigeti1 , L. C. Mangel1
1
U NIVERSITY OF P ECS, Department of Oncotherapy, Pecs, Hungary
Purpose: When treating prostate cancer using standard three-dimensional
conformal radiotherapy (3D-CRT ST) beam arrangements the rectum often
receive higher dose than its probable tolerance limits. Our aim was to elaborate a new planning method that similarly to intensity modulated radiation
therapy (IMRT) effectively spares the rectum without compromising the target
coverage.
Materials: The conformal rectum sparing (CONRES) five-field, non-coplanarplans were compared with ST plans for consecutive 27 low-risk prostate patients retrospectively. The total prescribed dose to the PTV which included
the prostate with safety margins was 74 Gy in 2 Gy per fractions. Optimal
beam arrangements were used consisting a left and a right wedged beampair and an AP beam inclined in the caudal direction. The wedge direction
determination (WEDDE) algorithm developed in our Institute was used toadjust the adequate direction of wedges. The aimed OAR dose limits were:rectum mean dose < 60 Gy, V40 < 65 %, V50 < 50 %, V60 <40 %, V70 <25 %, V75 <5 %, and bladder mean dose < 65 Gy, V65 < 35 %, V70 < 30%, V75 < 10 %, and femoral heads mean dose < 52 Gy where Vx(%) means
the percentage of total volume receiving x Gy. Conformity, homogeneity indexes, and z-test were used to evaluate and compare the different planningapproaches.
Results: The mean dose, the V40, and the V50 to the rectum, and the meandose, V40 to the bladder decreased significantly (p < 0.05 or better). Thechanges in the conformity, homogeneity, and in the doses to other organs at
risk were not significant.

Conclusions: The CONRES method significantly reduces the dose to therectum without any significant change in the conformity and homogeneity.
Using 3D-CRT the CONRES method can be a smart alternative to IMRT in
order to enhance the possibility of dose escalation.
1552 poster
CONSTRUCTION OF PLANNING SOFTWARE FOR INTRA-AXIAL
BRAIN TUMORS CONSIDERING ANISOTROPIC TUMOR EXTENSION ALONG NORMAL STRUCTURES
S. Tsutsumi1 , M. Hosono1 , D. Tatsumi1 , M. Yoshitaka1 , M. Yutaka1 , R.
Ogino1 , M. Tomoko1 , K. Ishii1 , Y. Takada1 , Y. Miki1
1
O SAKA C ITY U NIVERSITY H OSPITAL, Department of Radiology, Osaka,Japan
Purpose: In the external beam radiation planning for intra-axial brain tumors
such as glioblastomas (GBMs), the CTV margins should be determined byconsidering the anatomical structures of the brain. GBMs tend to spread into
the brain tissues anisotropically along neural fibers, and usually do not directly
invade the falx, tentorium, or skull, nor extend across the insula. We, thus,
developed a new method for contouring appropriate CTVs on 2D images for
intra-axial tumors.
Materials: In order to automatically create appropriate CTV margins, we havedeveloped software using C# language, in which, briefly, the CTV was generated by simulating tumor extension in the real brain, for example, tumors
refrain from expanding across the falx into the contralateral hemisphere.T2weighted magnetic resonance (MR) images of 20 normal brains were randomly adopted, and a single provisional GTV with a diameter of 1 cm wasplaced in the frontal and temporal lobes in 10 cases. Using the software,
the two types of provisional CTVs were generated by adding 2cm (CTV2)
and 3cm (CTV3) margins in all the directions on 2D images. The planned
provisional CTVs were evaluated by observers with neurological expertise; 3
radiation oncologists, 3 neuroradiologists and 3 neuropathologists. The areasof CTV2s and CTV3s generated by the software (newCTV2 and newCTV3)
were calculated and compared with those of reference generated by the conventional method (cCTV2 and cCTV3).
Results: We successfully demarcated the newCTV2s and newCTV3s at the
2 sites in all the 10 cases by the software. These were assessed as more acceptable by the observers than cCTV2s and cCTV3s.The areas of newCTV2s
were smaller by 10.8% and 11.4% in the frontal and temporal lobes, respec-S 578T REATMENT PLANNING AND DOSE CALCULATIONT REATMENT PLANNING AND DOSE CALCULATION

tively, than those of cCTV2s (p<0.01), and the areas of newCTV3s were
smaller by 21.1% and 13.2% in the frontal and temporal lobes than thoseof cCTV3s (p<0.01).

1554 poster
EVALUATION OF A COMMERCIAL AUTO-SEGMENTATION TOOL IN
THE OUTLINING OF LYMPH NODES & ORGANS AT RISK IN HEAD
AND NECK CANCER
C. Ingle1 , R. Parker2 , H. James1 , C. D. Scrase1
1

S UFFOLK O NCOLOGY C ENTRE T HE I PSWICH H OSPITAL NHS T, Ipswich
Suffolk, United Kingdom
C ENTRE FOR A PPLIED M EDICAL S TATISTICS U NIVERSITY OF C AMBRIDGE

2Conclusions: In this study, CTVs for brain tumors were algorithmically determined on 2D images with the software by considering the anatomical structures of the brain, and were assessed by neurological experts as more appropriate than the conventional CTVs. Consequently, irradiated normal tissues
were reduced by 10.8 to 21.1 %.It is essential to minimize irradiated areasof the normal brain tissue outside the CTVs of intra-axial tumors. Current
treatment planning systems sometimes do not generate appropriate CTVs
when using the auto-contouring functions, and as a result, there arise large
variations among individual radiation oncologists who manually define CTVs.
Our software provides unambiguously precise contouring and may become astandard method for intra-axial tumors.
1553 poster
DOSIMETRIC CHARACTERIZATION OF BRAINLAB NOVALIS
CONE-BASED STEREOTACTIC RADIOSURGERY
D. Zucca Aparicio1 , J. M. Perez Moreno1 , P. Fernandez-Leton1 , J. García
Ruiz-Zorrilla1 , A. Minambres1
1
H OSPITAL U NIVERSITARIO M ADRID S ANCHINARRO - G RUPO H OSPITAL DE
M ADRID, Servicio de Radiofísica y Protección Radiológica, Madrid, Spain
Purpose: Functional Radiosurgery is a treatment modality performed with
Cone-Based Stereotactic Radiosurgery (SRS) so small field sizes (down to
4.0 mm in diameter) are commonly used. The present abstract summarizes
the results obtained during the Commissioning of a SRS Treatment Planning
System (TPS) previous to the clinical implementation of this type of treatments for patients treated with SRS.
Materials: Cone-Based SRS Commissioning for BrainLAB iPlan RT Dose
4.1.2. (Feldkirschen, Germany) TPS requires the measurement of Nominal
LINAC Output, Relative Scatter Factors, Tissue Maximum Ratio (TMR) andthe Off-Axis Ratio (OAR) for each cone collimator (diameters of 4.0, 6.0, 7.5mm) following the measurement setup parameters (SSD and depth) based on
the BrainLAB Physics Reference Guide.PTW MP3 water tank with Mephysto
mc2 1.7.1. were used for the dose profiles and TMR measurements scannedwith PTW 60012 diode detector (SSD 92.5 cm and depth of 7.5 cm for theOAR)Nominal LINAC Output was measured for the 100 mm x 100 mm square
field size with a calibrated ionization chamber PTW 30013 (SSD 98.5 cm anddepth of 1.5 cm) as well as the Relative Scatter Factors with PTW 60012
diode detector and normalized to the calibration geometry.Relative Scatter
Factors measurements were performed aligning the diode detector with theradiation field for each cone collimator shifting along its CAX deviation. Jaw
positions were selected to define a square shape of 14 mm x 14 mm while
the mMLC was parked outside the radiation field.
Results: Relative Scatter Factors for the 4.0, 6.0, 7.5 mm cone collimators
were 0.646, 0.765, 0.812, while Nominal LINAC Output was 1.012 cGy / MU.
TMR scans were obtained to a depth of 210 mm with a scan resolution of 0.1
mm and OAR scans (both inplane and crossplane profiles) were obtained forthe range from -60 mm to 60 mm with a scan resolution of 1.0 mm.For TPS
input data reasons, OAR scans were processed with PTW DataAnalyze shifting all profiles along their CAX deviation, symmetrizing them and averaging
inplane with crossplane profiles for each cone collimator.
Conclusions: Clarkson Dose Calculation Algorithm is a measurement basedalgorithm which is used for Conical Collimator Dose Calculation with iPlan
RT Dose 4.1.2. so the good agreement between TPS dose calculations and
LINAC dose measurements relies on a good performance of the data obtained for the beam modelling in TPS for each cone collimator.

Purpose: Radical radiotherapy for head and neck cancer (HNCa) has greatly
advanced with the introduction of IMRT and IGRT. This requires accurate
manual location of organs at risk (OAR) and nodal stations which is time
consuming and subject to inter-observer variability. This study evaluated anauto-segmentation tool (BrainLab iPlan®) in the delineation of node stations
and OAR in patients with oropharyngeal cancer with regards to time taken
along with accuracy and reproducibility.
Materials: 5 patients were selected. GTV, CTV at 3 dose levels together
with brainstem, spinal cord, parotid and submandibular glands, mandible andcochlea were defined by 2 clinicians (C1 and C2). Auto-segmentation software was then run to include pre-defined nodal levels for each CTV and OAR.
Clinicians then re-edited these individually (C1A and C2A). A comparison oftime taken and Boolean analysis of overlap was performed between clinicians
and clinician-edited auto-segmentation volumes.
Results: With regards to nodal delineation, C1A took longer with a meandifference of 25.6 minutes (95% CI 14.9 to 36.3). For C2A this was 24.2
minutes (95% CI 6.9 to 41.5). For OAR, times for C1A were shorter by 35.8
minutes (95% CI 24.6 to 47.0 minutes) and for C2A 14.6 minutes (95% confidence interval of 6.0 to 23.2). The mean percentage difference in total (allCTVs combined) nodal volume (TNV) for C2 was -4.26% (95% CI -34.77% to+26.25%), for C1A +2.84% (95% CI -2.24% to +7.91%) and for C2A +7.09%(95% CI +1.37% to +12.80%) compared with the ’gold standard’ C1. The
mean percentage difference between C2A and C1A was +4.22% (95% CI 2.10% to 10.55%). For OAR, the mean percentage difference in total volume
combined (except cochlea) for C2 was +5.96% (95% CI 0.38% to 11.54%), for
C1A -0.32% (95% CI -3.08% to 2.45%) and for C2A +5.24% (95% CI +0.54%
to +9.95%) relative to C1. The mean false positive TNV was 15.9% (95% CI
10.3% to 21.5%) for C2, 18.5% (95% CI 14.6% to 22.3%) for C1A and was
18.3% (95% CI 12.5% to 24.2%) for C2A. The mean false negative TNV was
8.9% (95% CI 6.5% to 11.1%) for C2, 15.6% (95% CI 14.0% to 17.3%) for
C1A and 11.4% (95% CI 6.5% to 16.2%) for C2A. The mean false positive
total OAR volume was 12.6% (8.4% to 16.9%) for C2, 10.9% (95% CI 9.4%
to 12.3%) for C1A and 12.0% (95% CI 8.8% to 15.2%) for C2A. The meanfalse negative total OAR volume was 6.6% (95% CI 4.6% to 8.7%) for C2,
11.5% (95% CI 9.7% to 13.3%) for C1A and 6.9% (95% CI 5.2% to 8.5%) for
C2A.
Conclusions: The integration of an auto-segmentation tool in our experience significantly reduced outlining times for the OAR. Conversely, outlining
times for nodal volumes were significantly increased taking into account editing time. In general there was good concordance in nodal and OAR delineation between the two clinicians. There was no clear effect of the autosegmentation tool on the extent of false positivity and negativity. The applicability of an auto-segmentation tool in HNCa planning is thus uncertain.
1555 poster

S 579

Results: The average value of D98 for the conventional technique was
94.7%±1.4. The FIF technique improved the near-minimum dose in 79%
of the cases, raising D98 to 95.6%±1.4. HI is better with the FIF for 82% of
the cases. The differences between D50 and the average dose is less than
2% for both techniques but this was obtained through different dose plan normalizations: for the FIF the dose is normalized to the average dose in the
PTV for 100% of the cases whereas for the conventional technique a point
dose normalization was used in 30% of the cases to improve homogeneity.
No relevant differences have been found for OARs.
Conclusions: The FIF technique was introduced in the clinical routine since2008, with the pencil beam calculation algorithm, in order to improve homogeneity and whenever the dose minimum was less than 95% of the prescription dose. With the recent introduction of the collapsed cone algorithm theneed for the FIF approach is even stronger but the segments configuration
pattern changed.
1556 poster
HIPPOCAMPUS AVOIDING PROPHYLACTIC BRAIN IRRADIATIONFOR NSCLC PATIENTS: BACK TO BASIC WITH TWO OPPOSINGFIELDS
Z. Kesteren van1 , A. Olszewska1 , E. Lamers1 , J. S. A. Belderbos1 , E.
Damen1 , M. van Herk1 , C. van Vliet-Vroegindeweij1
1
T HE N ETHERLANDS C ANCER I NSTITUTE - A NTONI VAN L EEUWENHOEKH OSPITAL, Radiotherapy, Amsterdam, Netherlands
Purpose: The brain is one of the major sites of failure for stage III non-small
cell lung cancer (NSCLC), with approximately 22% of the patients developing
brain metastases. Prophylactic Cranial Irradiation (PCI) reduces occurrencesof brain metastases to 7%, and improves the disease-free survival and thequality of life. PCI in itself may, however, induce adverse effects like neurocognitive deficits. These effects may be reduced by the application of hippocampus avoiding PCI (HA-PCI). Planning studies showed that treatment
techniques such as helical tomotherapy (HT) and IMRT can significantly reduce the dose to the hippocampus. Prescribing 30 Gy in 10 fractions to thebrain on average a biological equivalent dose of 4.9 Gy (HT) and 7.3 Gy(IMRT) was delivered to the hippocampus with a PTV coverage of 95%. Using these sophisticated techniques the dose to the hippocampus might still
be too high. Based on the assumption that reduced coverage of the PTV in
PCI is acceptable, we developed a simple technique using two lateral beams
to deliver HA-PCI, in order to further reduce the dose in the hippocampus.
Materials: For 10 patients, the brain and hippocampus were delineated on a
CT scan matched with a 3D T1 weighted MR scan. For the PTV, defined as
the whole brain volume minus the hippocampus volume with a 5 mm margin,
30 Gy (12 fractions of 2.5 Gy) dose was prescribed. Two opposing fields of
10 MV were set up, using the MLC to shape the field around the brain for irradiation. The collimator angle was chosen such that two 1 cm leafs optimally
block the hippocampi. The maximum and mean dose to the hippocampus
was calculated, as well as the volume of the PTV receiving 95% of the prescribed dose (V95%).
Results: On average, the V95% of the PTV was 85.7 ± 0.6 %. The averagemean dose delivered in the hippocampus was 6.2 ± 0.3 Gy, the maximum
dose was 11.9 ± 1.6 Gy. The mean biological dose of the hippocampus was
3.9 ± 0.2 Gy, with α/β = 2 Gy.

FIELD-IN-FIELD VERSUS CONVENTIONAL TANGENTIAL PLANNING TECHNIQUE FOR BREAST IRRADIATION
M. Araújo1 , F. Rocha1 , A. C. Oliveira1 , J. Gaspar1 , L. Conceicao1 , M. D. C.
Lopes1
1
I NSTITUTO P ORTUGUÊS DE O NCOLOGIA DE C OIMBRA F RANCISCOG ENTIL , EPE, Medical Physics, Coimbra, Portugal
Purpose: A retrospective study was carried out in order to compare the conventional opposed tangential planning technique for breast irradiation with afield-in-field (FIF) approach. The aim of the study was to assess the qualityof the dose distributions in terms of dose-volume indexes and homogeneity.
Materials: The study included 67 clinical cases where 40 were treated in 4MV
and 27 with 6 or/and 15 MV photons. 56.7% of all cases corresponded to left
breasts. For each case two plans have been optimized using the pencil beamalgorithm in Oncentra MasterPlan v. 3.3. SP1 from Nucletron. Different planning tools have been used to obtain the best dose distribution in both techniques like opposed tangential field super-positioning with and without physical and/or dynamic wedges, bolus, small angular shifts, beam weights, etc.
The FIF technique included in addition smaller segments superimposed tothe conventional tangential incidences. For both plans different dose-volume
indexes have been compared. For the PTV dose coverage was assessed
through V95; overdosage volumes were calculated by V107 and following the
ICRU 83, the near-minimum dose (D98), the near-maximum dose (D2), themedian dose (D50) and also the homogeneity index (HI) have been computed. Concerning the organs at risk (OAR) also the relevant dose-volume
parameters have been calculated. Paired-sample T-test with a significancelevel of 5% was used to assess the statistical relevance of the differences
found.

Figure 1. Isodose display of the opposing field HA-PCI treatment. Isodose
contours of 28.5 Gy (95%) are shown, encompassing 85% of the PTV volume.
The hippocampi are also shown on the CT images.
Conclusions: Opposing field HA-PCI is a simple technique that has most of
the advantages of whole brain irradiation while a maximal sparing of the hippocampus was achieved. By accepting the V95% of the PTV to drop to 85%,
an excellent sparing the hippocampus can be achieved. It should be notedthat although our HA-PCI covers 80% of the brain, the performance of thetreatment may be worse than 8/9 of advanced HA-PCI techniques with 90%
brain coverage, since if multiple lesions occur there is a larger probability offinding one in the spared region. However, since in the current clinical practice no PCI is given, HA-PCI will still reduce the probability that a metastasis
occurs in the brain.Within the Netherlands, a side study of the NVALT 11 trial(randomized phase III trial with or without PCI in stage III NSCLC patients) iscurrently performed. The patients with and without (HA)-PCI have repeatedtests for neurocognitive functioning. At the NKI, the opposing field techniquewill be the technique of choice for HA-PCI.

S 580T REATMENT PLANNING AND DOSE CALCULATIONT REATMENT PLANNING AND DOSE CALCULATION

1557 poster

GTV size. No such tendency was observed for the mean dose to the GTV, forwhich the location of the tumour was found to be of greater importance.
Conclusions: The results of this study indicate that a new treatment planevaluation strategy is needed in order to preserve the evidence based patient
outcome. To maintain the established treatment technique, our new treatment
planning strategy, using the AAA, is to keep the field size relation to the PTV
and to preserve the delivered dose. The latter can be accomplished by using
a fixed normalising factor describing the relation between AAA and PBC. Thisfactor can be related either to the mean dose to the GTV or to the isocenter.

IMPACT OF DIFFERENT USERS ON TPS BEAM FITTING
E. Gershkevitsh1 , M. Lavrova2 , S. Bayankin3 , M. Gershkevitsh4
N ORTH E STONIA R EGIONAL H OSPITAL, Radiotherapy, Tallinn, Estonia
2
R EGIONAL C LINICAL H OSPITAL, Radiotherapy, St. Petersburg, RussianFederation
3
R EGIONAL O NCOLOGY C LINIC, Radiotherapy, Ekaterinburg, RussianFederation
4
TARTU U NIVERSITY C LINICS , C LINIC OF H AEMATOLOGY AND O NCOLOGY,
Radiotherapy, Tartu, Estonia
1

Purpose: The accuracy of treatment planning system (TPS) calculations depends on the number of reasons, such as correctness of input data, beamfitting process, limitations of algorithm and accuracy of verification measurements. In this work we would like to isolate and quantify the uncertainty associated with beam modelling process of the same input data performed bydifferent users of CMS XiO TPS.
Materials: Four radiotherapy departments received a copy of machines withpreloaded data in TPS specific format. The users were asked to fit the beammodel to their satisfaction following vendor guidelines and personal experience. Data of 6MV photon beam from Elekta accelerator and 15 MV photon beam from Varian accelerator were used in the exercise. All models
were later analysed using 2D gamma method with PTW Freiburg Verisoft
software. Dose distributions in water simulated phantom were created using
pencil beam convolution models fitted by different users for a number of open
and wedged fields and compared to the measured data.
Results: All the models passed gamma value of 95% for 3%, 3mm criteria
for the tests performed. However, some models were able to reach 95%
using 1.5%, 1.5 mm for all tests whereas others were only able to do so at
3%, 3mm criteria. Lowest gamma values were obtained for 25x25 cm2 open
beam fitting and largest wedged beam fitting.
Conclusions: The variability exists between the beam models with the same
input data created by different users. The automated beam fitting tools orprocesses may help to reduce user influence on the beam data modelling andincrease the consistency between measured and model calculated values.
1558 poster
IS IT SAFE? CALCULATIONAL ACCURACY VERSUS TARGET
DIAMETER FOR RAPIDARC PLANS
L. Fog1 , M. Aznar1 , J. Rasmussen1 , F. Kjaer-Kristoffersen1 , S. A.
Engelholm1 , J. P. Bangsgaard1
1
T HE F INSEN C ENTER - R IGSHOSPITALET, Radiation Oncology, Copenhagen, Denmark
Purpose: Previous work has reported "high spikes in the measured data"[for RapidArc plans] [1]. Measurements have indicated 15% overdoses in thecentres of very small fields treated with RapidArc [2]. In this work, we have devised a method for establishing the accuracy for stereotactic RapidArc plansfor various small target diameters, and determined the smallest diameter forwhich we find RapidArc treatments are safe. [1] Nicolini et al: GLAaS: An
absolute dose calibration algorithm for an amorphous silicon portal imager.
Applications to IMRT verifications, Med. Phys. 33 (8) 2006[2] Fog, L. et al.
"Size does matter: hot and cold spots in RapidArc plans using small fields",
poster no. 240, ESTRO 2010 (winner of the Young Scientists Poster Award).
Materials: RapidArc plans were made for targets of diameters 0.8, 1.0, 1.5,
2.0, 3.0, and 5.0 cm, in a cylindrical water phantom. Eclipse versions 8.6,
8.9 and 10.0 were used. The conformality (CI= V95% / Vtarget) and homogeneity (HI= Dmax/Dprescribed) indecies were calculated and compared toour institutional data for (non-RapidArc) stereotactic treatments. The plans
were delivered using a Varian Novalis TX, 2300 iX linac with 2.5 mm wide HD
MLCs. Measurements were carried out using the portal vision dosimeter andanalysed using EPIQA v. 1.3 (EPIdos s. r. o., Lesna 7, Ivanka pri Dunaji, 900
28, SLOVAKIA). Gamma criteria of 1mm, 6% were used in the analysis. P, thepercentage area of the dose map in which the data points passed the gamma
analysis, was determined. Extensive experience with quality control for RapidArc prostate plans has indicated good agreement between calculated anddelivered doses. Thus, since good agreement was expected for a target ofabout 5 cm diameter, P’; value of P normalised to P(5 cm target diameter)
was calculated for each gamma criterion and target diameter. Appropriate
gamma criteria will be discussed.
Results: The agreement between the calculated and measured dose worsened as the target diameter decreased (see figure). Using a criterion of P’90
> 90%, the smallest acceptable PTV diameter was 3 cm for Eclipse 8.6 and
8.9, and 1.5 cm for Eclipse 10.0.

1560 poster
MONITOR UNIT COMPARISON BETWEEN A TREATMENTPLANNING SYSTEM AND AN INDEPENDENT MONITOR UNITCALCULATION SOFTWARE
P. Carreira12 , L. Madureira12 , M. Mota12 , M. Pontes12 , T. Ribeiro1 , L.
Prudêncio1 , N. Teixeira34 , I. Monteiro Grillo1
1
H OSPITAL DE S ANTA M ARIA, Lisbon, Portugal
2
M EDICAL C ONSULT, Lisboa, Portugal
3
E SCOLA S UPERIOR DE T ECNOLOGIA DA S AUDE DE L ISBOA, Lisboa,
Portugal
4
FACULDADE DE C IÊNCIAS M ÉDICAS , U NIVERSIDADE N OVA DE L ISBOA,
Lisboa, Portugal

Conclusions: Using the method devised this work, and accepting deviationsof up to 10% relative to data for a 5 cm diameter PTV, we propose that RapidArc treatments should not be given to tumours with diameters less than 3.0
cm (Eclipse 8.6 and 8.9), and 1.5 cm (Eclipse 10.0). With improvements of
Eclipse calculations for very small MLC fields it may be possible to accurately
treat smaller targets with RapidArc.
1559 poster
MIGRATION OF DOSE CALCULATION ALGORITHM FROM PBC TO
AAA FOR STEREOTACTIC LUNG CANCER TREATMENT PLANNING
M. Hedetoft1 , F. Nordström2 , L. Ekberg3 , S. af Wetterstedt1 , S. Bäck12
1
S KÅNE U NIVERSITY H OSPITAL , M ALMÖ, Radiation Physics, Malmö,
Sweden2
S KÅNE U NIVERSITY H OSPITAL AND L UND U NIVERSITY, Medical Radiation
Physics, Lund, Sweden
3
S KÅNE U NIVERSITY H OSPITAL , M ALMÖ, Oncology, Malmö, Sweden
Purpose: Stereotactic treatments of small non-operable lung tumours havebeen carried out since 2001 at our clinic. The Pencil Beam Convolution(PBC) calculation algorithm in Oncentra MasterPlan (OMP, Nucletron) has
been used for treatment planning but a migration to Eclipse (Varian) and theAnisotropic Analytical Algorithm (AAA) has now been initiated. The PBC calculation algorithm has shortcomings in regions where charged particle equilibrium is lacking, i.e. in heterogeneous patient volumes. This is problematicfor target dose calculations in lung cancer treatments. In comparison, AAA
substantially improves the dose calculation accuracy in the lung region (Aarup
et al., RTO, 91, 2009).The aim of this study was to investigate the need for
new treatment planning strategies when changing the dose calculation algorithm for stereotactic lung cancer treatment, by comparing plans calculatedusing both PBC and AAA. This is essential in order to ensure the preservation of evidence based patient outcome data.
Materials: Twelve recently treated stereotactic lung cancer patients were included in this study. The present treatment planning strategy is to normalise
to 140% of the prescribed dose in the isocenter and assure PTV coverage ofapproximately 70% and a mean dose to the GTV of approximately 140%. All
investigated plans contained 5 fields with nominal beam energy of 6 MV. Dose
distributions calculated for the same number of monitor units were analyzed
using both the PBC and the AAA dose calculation algorithm. The investigatedparameters were absorbed dose to the isocenter and min/max/mean/mediandose to the GTV/CTV/PTV, respectively.
Results: As expected large differences, when comparing AAA to PBC calculated dose distributions, were found in both lung and tumour tissue. The
mean difference in absorbed dose to the isocenter was -5.3% ± 3.4% (1s.d.) and for the mean absorbed dose in GTV it was -18.5% ± 6.9% (1 s.d.).
The larger difference for the GTV compared to the isocenter is caused by ahigher degree of charge particle disequilibrium, which AAA more accurately
accounts for. The difference between the algorithms with respect to calculated isocenter dose was found to decrease linearly (R2 =0.41) with increased

Purpose: Monitor unit (MU) calculation is a vital process in external beam radiotherapy in order to assure a correct dose distribution and agreement withtreatment prescription. The intent of independent MU calculation software isto verify the MU calculation of the treatment planning system (TPS). Utilization of MU independent calculation software is recommended by the American Association of Physicists in Medicine TG-40 for quality assurance of TPS.
The main goal of this study is to compare the MU calculation of TPS with theindependent MU software calculations for several reference fields. Furthermore, differences in phantom ionization chamber dose measurements, with
MU calculations from both systems, were also object of evaluation.
Materials: The machine characterization, for the independent MU calculation
software RadCalc® V6.0, were made according to software specification andlinear accelerator ELEKTA Synergy data from commissioning. The TPS XiO®
V4.40 with superposition algorithm and the same linear accelerator data wasused.Several reference fields with different photon beam energies, sizes, collimator and gantry angles as well as wedges were created on XiO. For tissue
heterogeneity evaluation CIRS Pelvic phantom was used with different inserts(bone, water and air). The fields were exported to RadCalc for calculation and
to ELEKTA Synergy control system for absolute dose measurements in CIRS
phantom with a 0.125 cm3 PTW ionization chamber. The IAAE TRS-398 protocol was followed for dose correction. Results for MU calculations and dose
measurements, from XiO plans and RadCalc, were compared and analyzed.
Results: The difference in MU from TPS and RadCalc was about 2% for fieldsize less than or equal to 15x15 cm2 , increasing to 5% for larger fields. For
more complex fields, with wedge and collimator rotation in heterogeneous
medium, the results show differences up to 7%.
Conclusions: The XiO MU calculation difference to RadCalc was studied
and determined for several reference fields including most of beam modifiers
and tissue heterogeneities. With these results we should be able to evaluate
real cases differences. Therefore RadCalc should be an important tool for
TPS quality assurance in our external beam radiotherapy department.
1561 poster
MR SPECTROSCOPY IMAGING IN RADIOTHERAPY TREATMENTPLANNING OF THE PROSTATE: DOSE PAINTING THE DOMINANTLESION.
J. Simpson1 , D. Loria1 , A. Kazi2 , G. Godwin1 , G. Sasso3
1
AUCKLAND R ADIATION O NCOLOGY, Auckland, New Zealand
2
T HE TOWNSVILLE H OSPITAL, Douglas, Townsville, Australia
3
AUCKLAND C ITY H OSPITAL, Auckland, New ZealandPurpose: The majority of prostate cancers are multifocal with dominant intraprostatic lesions (DIL) containing an increased number of clonogens. TCP
as a function of both clonogen number and dose may be improved by dosepainting the DIL to higher levels of dose. Magnetic resonance spectroscopy(MRS) can identify the DIL as a region with a higher choline to citrate ratio(Cho/Ci) compared with normal prostatic tissues or benign hypertrophy. The
aim of this study was to demonstrate that dose-painting the DIL can lead toincreased TCP without significant effect on rectal NTCP and that MRS may
act as a guide for dose-paining by number.
Materials: A patient with a high risk localised prostate cancer, no history ofprior radiotherapy and no evidence of distant metastatic disease, was chosen
for this study. TRUS biopsy revealed adenocarcinoma of prostate. MRS examination was performed using a PRESS sequence to identify the DIL andwas co-registered with planning CT. In addition to our institutional standard
78Gy IMRT plan, the DIL was boosted by one of two methods. Firstly the DIL
was dose painted by contour with a range of boost doses from 10% to 50%.
Secondly the DIL was dose painted by number using the Cho/Ci ratio and a

S 581

simple assumption that tumour cells increase linearly with Cho and inverselywith Ci signal. To compare plans, TCP and rectal NTCP were derived for arange of initial clonogen numbers N0. The effect of the relative DIL clonogendensity was evaluated by varying the assumed ratio of clonogens in DIL toremaining prostate.
Results: The degree of TCP increase with DIL boost was dependent upon
the initial clonogen number N0 used. At the upper limit of N0 (109 ) the TCP
improved from almost 0 to >0.9 as the DIL was boosted to 30%. The required boost % decreased with N0 since a high level of tumour control was
more easily achieved. If a high % of the overall clonogen count occurred in
the DIL then the overall TCP approached 100% with sufficient DIL boost. As
the relative DIL clonogen count decreased the TCP was ultimately limited by
the control of the rest of prostate. With 107 clonogens of which 90% were
within the DIL, a 10% boost improved the TCP from 0.95 to >0.99; with 109
clonogens a 30% boost was required to improve the TCP from 0.01 to 0.95.
In all plans the mean rectal NTCP was 0.04 and was not significantly dependent upon the boost % (p<0.001). In the case of dose painting by number
the maximum Cho/Ci ratio in the DIL was 9 times that of the remainder ofthe prostate, simplistically suggesting a relative clonogen density of DIL toremaining prostate ratio of 3:1, requiring in turn an additional dose of 15% to
the DIL in order to achieve the same TCP.

Conclusions: Dependent upon the initial cell number and assumed radiosensitivity, the TCP-boost dose relationship may be highly sensitive to theassumed initial cell number. That there may be a large inter-patient spreadof N0 even within the same prostate cancer risk grouping has profound implications for the optimal dose-painting level to the prostate DIL. MRS may be
used as a quantitative dose-painting guide with a realisation of the limitationsof the model used.
1562 poster
OPTHALMIC APPLICATOR MEASUREMENTS WITH DIODE DETECTOR
P. Sipila1 , H. Järvinen1 , I. Jokelainen1 , J. Niemelä1 , J. Heikkonen2
1

R AD. AND N UCLEAR S AFETY AUTHORITY (STUK), Helsinki, Finland
H ELSINKI U NIVERSITY C ENTRAL H OSPITAL, Radiotherapy, Helsinki,
Finland2

Purpose: Iodine seeds are also used in opthalmic applicators to treat ocularcarsinomas, mainly uveal melanoma. In most radiotherapy centers the distribution is calculated only with a treatment planning system, which usuallycan not handle radiation scatter and partial schielding properly. This could
lead up to tens of percentage dose discrepancy to actual treatment dose.
The dose distribution of four different opthalmic applicators from Helsinki University Hospital were measured and compared with the treatment planningcalculations.
Materials: The applicators were pure gold (24k) plagues of the CCC and
CCB type, where 12 or 10 BEBIC IsoSeed I25.S16 seeds were attached withsilicon mold. Two applicators have also an engraved groove for the seeds inouter ring. These outer ring seeds were enbedded in gold in order to shield
the optic nerve and focus the radiation to target. For the measurements,
the applicators were fixed in a holder and inserted in a water phantom. The
detector (IBA/Scanditronix SFD) was moved with a XYZ micrometer linear
controller and connected to a Keithley 6517A high precision electrometer. The

S 582T REATMENT PLANNING AND DOSE CALCULATIONT REATMENT PLANNING AND DOSE CALCULATION

movements of the detector could be positioned with about 0,02 mm accuracy.
The active area of the detector is 0,5 mm x 0,5 mm x 0,01 mm, which allows
great accuracy even in steep dose gradients.
Results: The single seeds were first calibrated with a well chamber (Standard Imaging HDR +1000) and later used to calibrate the diode detector for
absorbed dose to water. The SFD detector has been previously proven toaccurately measure the depth dose of single seed and with this work it was
found to be a suitable instrument for measuring the dose distribution aroundmultiple seeds. The diode is small enough to detect accurately high gradientpositions and sensitive enough to measure low dose areas. The measurements showed that the treatment planning system was not able to calculate
the scatter and shielded radiation properly, thus leading to too large dosedeviation for patient care.
Conclusions: The well chamber was found to be a suitable transfer instrument for calibrating the single seeds. The diode detector could then be calibrated with these single seeds and then used to measure the absolute dose
distribution around the applicator. Measurements showed severe drawbacks
with the planning system, mainly regarding partial shielding. In the presentation, the differences of the measured and calculated dose distribution will
be described in more details. This work has been carried out as a part of EC
funded EMRP projects T2.J06 (Increasing cancer treatment efficacy using 3D
brachytherapy).
1563 poster

algorithm and planCC using the classic collapsed cone algorithm. Each pairof plans was then compared in terms of Monitor Unit (MU) calculation andisodose coverage of the PTV.
Results: For identical beam arrangements and equal beam weightings between planPB and planCC of each patient, the MUs calculated using the
pencil beam algorithm were in all cases less than those calculated by the collapsed cone algorithm. Differences in MUs ranged from -0.5% up to -7.6%(median -2.5%). Furthermore, the 95% isodose encompassing the PTV wasshrinked in volume by about 10% when using the CC algorithm instead of the
PB algorithm. In planPB the 95% of the PTV volume received about 5% moredose than in planCC. Plato TPS PB calculation lied in between Oncentra TPS
PB and CC.
Conclusions: The pencil beam algorithm overestimates dose in lung regions
compared to the collapsed cone algorithm. MU calculations and field size selection need to be carefully assessed to avoid underdosage of the PTV whencalculating with pencil beam method, since CC method is established as moreaccurate in inhomogeneous regions. Further investigation and comparison
could be done for 18 MV photon beams.
1565 poster
SIMPLE MATHEMATICAL WEIGHTS OPTIMIZATION FOR THREE
FIELDS 3D-CRT PLANS.
M. Gizynska1 , P. Kukolowicz1
1

OPTIMIZATION OF 3D PLANNING DOSIMETRIC IN BREAST
PHANTOM FOR MATCH REGION OF SUPRACLAVICULAR AND
TANGENTIAL FIELDS
S. nourollahi1 , M. Esfahani2 , M. Allahverdi1 , V. Changizi1
1
T EHRAN U NIVERSITY OF M EDICAL S CIENCES R ADIATION O N, Tehran, Iran
Islamic Republic of2
I MAM K HOMEINI H OSPITAL , C ANCER I NSTITUTE, Tehran, Iran Islamic
Republic ofPurpose: To create dose distribution in match region SCF(supraclavicularfield) and tangential beams utilizing gafchromic EBT film dosimetry to measure relative dose distributionComplexy of geometry breast and lung inhomogeneity in PTV cause perturbation in dose distribution. This problem canbeget overdose or underdose in match region of three fields. If fields aren’t
accuracy align, it causes consequence of having such as cosmetic results.
Materials: In this study we used anatomical slab phantom with cork lung inhomogeneity and plexy colored heart part. Our measurements carried out by
Gafchromic EBT film. Advantages of EBT film such as 2 dimentional detector,
high resolution and no processing make it appropriate for this study. 4 pieces
films placed vertically in match line in four regions of measurement. Exposure
was performed with linear accelerator Varian 2100 Clinac using 6MV photon beam and Rt dose plan software to 3D calculation.We used conventional
method with SSD match and 3D with isocentric match. Also, Combination ofparameters such as gantry rotation, collimator rotation, asymmetric fields andcouch rotation were utilized. No shield and wedge applied in this study
Results: Methods with different degree of complexity were used for match
line between supraclavicular and tangential fields. In asymmetric beam
matching we have to use two abutment isocentrics. Results demonstrated
differences between techniques both 3D and Conventional techniques andusual conventional method showed more inhomogenity, but conventional by
gap parameter have not be seen different results by 3D techniques. In asymmetric fields we had much better results in match region.
Conclusions: This study revealed that EBT film is a proper tool for 2D distribution dosimetry and relative dose information. On the other hand, withthis dosimeter system found better results to decreas dose inhomogenity inmatch region fields.
1564 poster
PENCIL BEAM VS COLLAPSED CONE TREATMENT PLANNING
SYSTEM CALCULATION ALGORITHM IN 3D PLANNING OF LUNGCANCER.
T. Paschalis1 , A. Silyvridou1
1
ATHENS M EDICAL C ENTRE, Medical Physics Department, Athens, Greece
Purpose: Treatment planning system (TPS) calculations in inhomogeneous
regions, such as lungs, may present significant inaccuracies due to loss ofelectronic equilibrium. In this study, two different dose calculation algorithms,
pencil beam (PB) and collapsed cone (CC), provided by our planning system,
were compared trying to assess their impact on 3D planning of lung cancer.
Materials: A retrospective analysis of 20 lung cancer patient plans was carried out. GTV, CTV, PTV and organ at risk delineation was performed according to our institution protocols on the Nucletron Oncentra Masterplan (Version
3.3 SP3) Image Registration module, on 5mm CT slices taken under normal
respiration conditions. To avoid increasing penubra region due to larger secondary electron range in the low density media, only 6MV photon beam combinations were selected and optimized. Two 3D plans (calculation grid size2mm) were calculated for each patient, planPB using the classic pencil beam

M ARIA S KLODOWSKA -C URIE M EMORIAL C ANCER C ENTRE AND I NSTITUTEOF O NCOLOGY , Medical Physics, Warsaw, Poland

Purpose: The aim of conformal radiotherapy is to deliver the uniform prescribed dose to the target and spare surrounding tissues. In forward planning
this aim is achieved by the trial-and-error method which may be quite time
consuming. The aim of our work was to design the simple and fast method ofdose distribution optimization in the target volume.
Materials: We have assumed that highest possible homogeneity is achieved
when the gradient of dose distribution in the center of the PTV is zero. The
desired homogenous dose distribution in the PTV was achieved by solving
the system of equations (Di is dose from ith beam, Dp is prescribed dose, wi
weight of ith beam defined at the ICRU Reference Point):

wi · Di (ICRU ) = Dp (ICRU )iwi · Di (ICRU ) = 0i

In the first step we tested our method for 10 patients with prostate cancer
by comparing homogeneity of dose distributions achieved with the proposed
method with those prepared by experienced planners. For each patient
three fields conformal plan (15 MV x-ray) was created with the Eclipse
Treatment Planning System. The method was tested separately for fourmechanical wedge (wedge angles: 15◦ , 30◦ , 45◦ , 60◦ ). We have evaluatedthe homogeneity of dose distribution with three indices: standard deviation,
minimum dose and maximum in the PTV. In the second step we tested how
well the method works for minimizing the dose delivered to rectum and tokeep the maximum dose to the femoral heads below the accepted value.
Additional equation was introduced (FH stands for Femoral Heads):wi · Di (F H) = Dmax (F H)

the graphs of both functions. Considering dose volume histograms, sets ofplans with DVHs at a bounded L distance from a given plan are shown toyield similar values of quality indexes, as long as they exhibit continuity anddifferentiability.
Results: A set of operators can be obtained from ordinary evaluation problems. Particularly, continuity in biologically guided radiation therapy optimization problems is studied, with several conclusions directly applicable in practice.
Conclusions: L distance creates a structure suitable for defining continuity
and differentiability in the space of dose volume histograms. Therefore, it ispossible to quantify departures from well known solutions when an optimization process is in progress. L distance is a measure with a straightforward
graphical interpretation. It can be easily computed and provides a bound on
the variations of continuous quality indices with regards to a reference plan.
These differences can be evaluated with almost no computational complexity,
and therefore it is a powerful tool for optimization routines.
Conclusions: Proposed algorithm is simple in use and significantly speed up
the treatment planning. It allows to introduce organs at risk constraints andcalculate optimal wedge angles.
1566 poster
THE EFFECTS OF SYSTEMATIC ROTATION ON THE DOSE DISTRIBUTION OF PAROTID GLAND PATIENTS.
B. O hAllurain1 , M. Broderick1 , M. Coffey1
1
T RINITY C ENTRE FOR H EALTH S CIENCES, Discipline of Radiation Therapy,
School of Medicine, Dublin 8, Ireland Republic ofPurpose: The purpose of this study is to look at the effect of systematic
rotational errors on the dose distribution of parotid gland treatments.
Materials: The computed tomography (CT) data sets of five anonymousparotid patients were planned using conventional wedged-paired oblique
beams. Additional lateral boost fields with low weighting were added toachieve optimal planning target volume (PTV) coverage and minimal doseto the surrounding organs at risk (OAR). The anterior-oblique beam of eachplan was used as a reference beam and rotated laterally or medially by increments of 0.5◦ up to a total of 10◦ . All other beams were adjusted in the same
direction accordingly. Minimum dose (Dmin) coverage to the PTV along withthe maximum dose (Dmax) to the brainstem, spinal cord, optic chiasm andoptic nerves and the mean dose (Dmean) to the contralateral parotid gland
were analysed.
Results: The effects of systematic rotational error can have implications on
the treatment plan of parotid patients with respect to minimum coverage of the
PTV and maximum dose to the brainstem and spinal cord. Rotational errorsof 3◦ in either direction resulted in a decrease in Dmin to the PTV of <2%.
Rotation in the lateral direction up to 5◦ saw no decrease in the Dmin beyond
2% and only decreased by >5% at 7.5◦ . Medial rotation showed a mean
decrease in Dmin of the PTV by 8.22% at 5◦ . Rotation in either direction up
to 3◦ saw no increase in the Dmax >2Gy to either the brainstem or spinal
cord. Medial rotation of 5◦ resulted in an increase in Dmax to the brainstemand spinal cord by 3.3Gy and 2.5Gy respectively and at 6◦ these increased to
4Gy and 3.2Gy respectively. At 7.5◦ rotation the mean increase to maximum
dose to the brainstem and cord was 5.23Gy and 4.32Gy respectively. The
extent of these effects is however dependant on the individual patient.
Conclusions: Systematic rotational errors can lead to decreases in minimum
coverage of the PTV and increases in the maximum dose to the brainstemand spinal cord. The extent of these dosimetric effects is patient dependent
but there is a trend for medial rotation of the gantry to have a greater effecton the treatment plans than lateral rotation.

i

Results: Mean difference of standard deviation (SD) obtained by the proposed algorithm and by the trial-and-error forward planning was 0.1% (range
from -0.1% to 0.5%). For 45◦ wedge angle for 6 patients SD was almost
the same. For three patients difference was close to 0.1%. For one patient
the difference was 0.4%. The optimal wedge angles were different from thatobtained in forward planning and allowed to decrease the maximum dose delivered to rectum (the difference in wedge angle didn’t exceed 10◦ ). For dose
constraint for FH (dose < 85% of prescribed dose) optimal wedge angle was
between 30◦ and 45◦ .

S 583

1567 poster
THE USE OF A LÉVY METRIC IN TREATMENT PLANNING OPTIMIZATION
F. Cutanda Henríquez1 , S. Vargas Castrillón2
1

H OSPITAL G ENERAL U NIVERSITARIO G REGORIO M ARAÑÓN, Nuclear
Medicine, Madrid, Spain
2
CIEMAT, LAboratorio de Metrología de Radiaciones Ionizantes, Madrid,
Spain
Purpose: In this work the concept of L distances between Dose Volume Histograms (DVHs) for the same volume of interest is developed. This concept
helps design constraints on DVHs ensuring limited variations on some dose
distribution quality indices. L distance is a global property, with a straightforward geometric interpretation, and rigorous mathematical foundations. Variations on well defined optimization goal functions like radiobiological indices(TCP or EUD) can be easily related to L distances, providing guidance for
evaluation. In fact, if a planning quality index shows a minimum set of properties regarding the L metric, basic mathematical properties of the index canbe derived.
Materials: In probability theory, L distance between two distribution functions
is defined as the side of the largest square that can be inscribed between

1568 poster
TOMOTHERAPY MVCT IN 3D-CONFORMAL TREATMENT PLANNING
K. Schubert1 , T. Maric1 , S. Nill2 , G. Sroka-Perez1 , K. Herfarth1 , U. Oelfke2 ,J. Debus1
1
U NIV. K LINIKUM H EIDELBERG, Heidelberg, Germany
2
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Heidelberg, Germany
Purpose: In 3D-conformal radiotherapy dose distributions are calculated on
the basis of a treatment planning kVCT scan. In the presence of materials with a high Z-value like steel or titanium those images contain artefacts.
Wrong density information is included in the images, which will cause problems during the delineation of target volumes and sensitive structures. Furthermore, the dose calculation algorithms will deliver wrong results when thedensity information is not correct.Those artefacts are reduced when a MV
beam is used to acquire the images. Due to the higher beam energy the soft
tissue contrast is, however, reduced as well. This study investigates how big
the advantage for dose calculation is when an MVCT is used instead of akVCT.
Materials: A phantom of water equivalent RW3 slabs (30cmx30cmx1cm) was
modified to hold up to 5 layers (8cmx8cmx1cm) of MCP96. Four different
configurations (0/1/3/5 cm of MCP96) of this phantom were scanned with a
Siemens Sensation 4 with 120kV and with the MVCT of Tomotherapy HiArt
II system using an energy of 3.5 MV. The slice thickness was 4 mm and amatrix of 512x512 was used. The density of MCP96 and the corresponding
Hounsfield units were entered into the CT calibration table of the VIRTUOS
treatment planning (DKFZ, Heidelberg). For both modalities a static beamwith an aperture of 7x7 cm, an energy of 6MV and a perpendicular incident
on the phantom and the MCP96 inserts was calculated using a pencil beamalgorithm.Measurements in the phantom were performed using a cylindricalionization chamber with a sensitive volume of 0.3 cm. The measurement
point was located 3 cm behind the last MCP96 slab.
Results: The dose calculation without any MCP96 inserts shows good agreement (≈1%) with the measurement for both CT data sets. For the setups with
1 cm, 3 cm and 5 cm of MCP96 the deviations for the MVCT based calculations (-3%; +11%;+4%) were considerably smaller than the kVCT based
calculations (-40%;-23%;-28%). While the depth dose curves for the MVCTs
show a significant effect when the beams enter the MCP96, the ones calculated on the kVCTs are passing through the MCP96 without a pronounced
change in the gradient.A comparison of the density profiles through the phantom scans shows a superior identifiability of the MCP96 slabs for the MVCT
scans.
Conclusions: The more pronounced artefacts in the kVCT lead to a significant deviation in the dose calculation behind the MCP96 slabs. Using the
Tomotherapy MVCT images for dose calculation results in clear advantages
compared to kV imaging when materials with a high Z-value are present.
1569 poster
TPS DOSIMETRIC EVALUATION USING 1540-IAEA PACKAGE AND
MONTE-CARLO SIMULATIONS
Y. Benhdech12 , S. Beaumont2 , D. Autret3 , J. P. Guédon1
1
IRCC Y N (UMR CNRS 6597) - U NIVERSITY OF N ANTES, Nantes, France
2
Q UALIFORMED S ARL, La Roche Sur Yon, France
3
CRLCC PAUL PAPIN, clinical institute, Angers Cedex 01, France
Purpose: The IAEA has published a technical guideline in 2007 that provides
a step-by-step recommendation for both manufacturers and users on how
to carry out dosimetric quality control of Treatment Planning Systems. The
TECDOC-1540 contains experimental reference measurements in many situations: simple geometry (square and rectangular, SSD variation) and complex geometry (irregular fields, blocked and wedged fields, inhomogeneities,
asymmetric collimator setting).We have simulated all TECDOC-1540 tests(i.e. 18 tests) using PENELOPE Monte-Carlo methods on one hand; onthe other hand X6 and X18 beam data from the package were modeled inS 584

T RIALS : T ECHNIQUES , DOSIMETRY AND QA

T RIALS : T ECHNIQUES , DOSIMETRY AND QAECLIPSE TPS.The purpose of this work is to confront IAEA TECDOC-1540
dose measurements, Monte-Carlo simulations and TPS dose calculations using all proposed IAEA tests.
Materials: The 6 and 18 MV photon beams from the TECDOC-1540 package were simulated using PENELOPE code on a cluster computer (4 nodes
Altix XE-340, with 32-core Intel Xeon clocked at 2.53 GHz). The accelerator,
ELEKTA, geometry and materials were modeled.The electron initial parameters were found by comparison with various IAEA data measurements (depth
dose curves and profiles). The commissioning step is based on the use of
two cost functions: Gamma (Low 1998) and Chi index (Bakai 2003). This
ELEKTA accelerator was also modeled in ECLIPSE TPS (v. 8.6.15) from
VARIAN using IAEA measured data. An in-house program has been developed to convert this data into a format compatible with ECLIPSE.All tests
proposed by IAEA were created on the TPS (Anisotropic Analytical Algorithm:AAA) and in PENELOPE code. The doses were computed on both systems
in all specific points (as recommended).
Results: IAEA versus Monte-Carlo: the results show a strong coherence between MC simulations and the IAEA measurements with a maximum relative
difference of 2%. IAEA versus TPS: work in progress.Monte-Carlo versus
TPS: work in progress.
Conclusions: We use the IAEA TECDOC-1540 to assess the performanceof AAA algorithm used in Varian ECLIPSE TPS and to demonstrate the reliability of our Monte-Carlo simulations based on an ELEKTA LINAC model
built in PENELOPE.Results demonstrate the accuracy of Monte-Carlo methods and they confirm that methods are a perfectly acceptable alternative todose measurements for the TPS dosimetric quality control.
1570 poster
USE OF CONTRAST-ENHANCED COMPUTED TOMOGRAPHY(CE-CT) IN CONFORMAL RADIOTHERAPY TREATMENT PLANNING
E. Szántó1 , K. Hideghéty1 , L. Ruskó2 , G. Molnár2 , N. Zoltán1 , E. Fodor1 ,Z. Varga1 , S. Gaal1 , B. Vereb1 , L. Zag1 , A. Cserháti1
A LBERT S ZENT-G YÖRGYI U NIV.M ED.S CH ., Department of Radiotherapy
Oncology, Szeged, Hungary
2
GE H EALTHCARE H UNGARY, Budapest, Hungary
1Materials: The study was designed using water phantom and Alderson phantom, followed by calculation of doses for groups of 30 patients with laryngeal
and prostate cancers. Ionisation chambers were used to measure doses inwater at distances from beam edges ranging from 2 to 102 cm. TLD100 wereused to measure dose from photons and TLD600 from neutrons in Alderson
phantom. Doses were normalised to 70 Gy (laryngeal cancer) and 76 Gy(prostate) at the central beam axis (CAX) on reference depths for photonsof 6 and 20 MV and electrons of 6 and 22 MeV.Patients received IMRT/SIB
using 6 MV photons: ptv154 Gy, ptv260 Gy in 30 fractions; for all of them,alternative 3DCRT treatment plans were retrospectively generated using 6
and 15 MV in the 1st phase: ptv150 Gy, in the 2nd phase: ptv260 Gy at
2 Gy/day; For dose comparison in OARs, a specific index was elaborated,which accounted for mean doses associated with 9 sub-volumes associatedwith 10%90% volume with a step of 10%. Dose distribution calculations up
to the distance of 5 cm from the field edge were done using Eclipse and formore distant OARs using Monte Carlo algorithms. OARs considered weremandible, cerebellum, brain stem, thyroid gland, lungs, testes and bladder.
Results: Doses in water (normalized to 70 Gy in CAX) were: for 6 MV: 14.2
mGy (0.02 %) at the distance of 60 cm from CAX and 3.2 mGy at 102 cm;
for 20 MV: 20.5 mGy (0.03%) at 60 cm and 5.1 mGy at 102 cm; for electronsof 6 MeV: 2.5 mGy at 102 cm from CAX and for 22 MeV: 1.1 mGy. Closer tothe target, doses were higher. For 6 MV at 2 cm from the field edge: 9.4%
(6.61 Gy), and at 15 cm 1.09% (0.76 Gy); for 20 MV at 2 cm: 7.8% (5.46 Gy),
and at 15 cm 0.82% (0.58 Gy).Measured doses in Alderson phantom fromprostate irradiation ranged in thyroid gland from 0,50 to 0,69 Gy for 3DCRT
and from 2,47 to 3,09 Gy for IMRT, respectively.Calculations showed higher
doses at IMRT than at static fields for the cerebellum. The doses associatedwith volumes were higher for IMRT than for static fields: for V90% by 5.310.13
Gy; for V60% by 10.100.27 Gy, for V30% by 24.471.05 Gy. Moreover, a tendency was observed that with the volume growing bigger, the dose difference
became smaller for the whole group.
Conclusions: Photon and electron doses scattered far from the target were
below 20 mGy, while at 15 cm they were close to 1 Gy. In some cases, the useof the static fields led to a lower dose in OARs. The inclusion of significantly
more patients is needed to reveal potential statistical differences for distantOARs.
1572 poster

Purpose: To investigate inter-observer target volume delineation differenceson CE-CT scans and feasibility of using CE-CT with image fusion for radiotherapy planning of different tumours.
Materials: 13 primary and secondary liver tumor for stereotactic irradiationand further 17 consecutive cases (7 lung, 5 head and neck, 5 rectal tumour) for 3DCRTwere selected. Each patient was positioned and immobilized with thermoplastic mask using AIO SolutionTM (ORFIT, Belgium). Twoseries of CT were aquired for planning before and after intravenous contrast agent. Both sets of CTs were loaded and than co-registered in Oncentra TPS. Gross tumor volume (GTV) was delineated by 3-4 operators.
Inter-observer and intra-observer variability were assessed by the comparison of average (AVG)and the standard deviation (SD) of tumor volumes andthe volume- topography agreement level by the volume overlap index (VOI).
ANOVA (SPSS v.16) was performed to evaluate differences in inter-observer
and intra-observer variability based on tumor localisation, size complexity(multiple lesions/diffuse perifocal invasion) and observer experiences (highlevel of experience, trainees)
Results: For the whole population the smallest GTV was 7 cm3 and thelargest 1990 cm3 . The range of SD 0,1-74 , SD/AVG 0,01-0,35 were forliver, SD 0,9-0,28 SD/AVG 0,00-0,22 for lung, SD11-55, SD/AVG 0,04-0,37
for rectal cancer and SD 8-51, SD/AVG 0,07-0,55 for head and neck tumours
respectively. The majority of the cases the VOI was between 65-75% (37%93%). VOI improved with the use of CE-CT as compared to conventional CT.
Tumor localisation, size and case complexity (simple versus complex) proved
to be significant factors for tumour delineation error.
Conclusions: Use of CE-CT is an effective measure to reduce inter-observer
and intra-observer tumour volume delineation variability in order to deliver
conformal or stereotactic radiotherapy. The dose difference would be caused
by intravenous contrast agent can be avoided by image fusion.
1571 poster
VERIFICATION OF DOSES IN ORGANS DISTANCED FROM TARGETFOR STATIC FIELDS AND IMRT DURING HEAD AND NECK, AND
PROSTATE RADIOTHERAPY
M. Peszynska1 , J. Malicki2
1
C OPERNICUS M EMORIAL H OSPITAL , R EGIONAL C ANCER C ENTRE,
Department of Medical Physics and Radiation Safety, Lodz, Poland
2
G REAT P OLAND C ANCER C ENTRE, Poznan, Poland

Purpose: Each year, over 500,000 patients in Europe receive radiotherapy.
Out of that, 150,000 are IMRTs, which leads to the population problem associated with low doses in the whole body.Aim. To check the doses in organs
at risk (OAR) which lay close and far from the target for 3DCRT (static fields)
and IMRT of prostate and laryngeal cancers.

VOLUMECHANGESDURINGCHEMORADIOTHERAPY/RADIOTHERAPY WITH CURATIVE INTENTION: A PROSPECTIVE STUDY
K. Hideghéty1 , A. Cserháti1 , E. Szántó1 , N. Zoltán1 , E. Fodor1 , Z. Varga1 ,Z. Együd1 , A. Maráz1 , L. Thurzo1
A LBERT S ZENT-G YÖRGYI U NIV.M ED.S CH ., Department of Radiotherapy
Oncology, Szeged, Hungary
1

Purpose: The aim was to investigate prospectively the changes in the tumor
volume prior to definition of boost volumes and to evaluate the clinical impactof the repeated, co-registered treatment planning CT for 3DCRT and IMRT in
the curative management of different macroscopic tumours.
Materials: From 2005 september to 2010 april 321 patients (24 pts sufferingof advanced oesophagus-, 106 pts of head-and-neck- and 192 pts of lungcancer) underwent standard positioning using AIO SolutionTM and thermoplastic mask fixation (ORFIT) and planning CTo(Siemens Somatom Emotion
6 CT). After delivery of 45-50 Gy to the planning target volume (PTV) encompassing the contoured gross tumour volume (GTV) and elective nodal regions
a the planning CT1 was repeated. Image fusion The volume changes of grosstumorr volume (GTV) and GTV1 and the resulting changes to planning target
volume 1 (PTV1) and PTV2 were detected and analysed.
Results: The individual mask had to be renewed in 8% o due to marked
body or tumour changes. Gross tumor volume increased in great degree(in average 4 times larger (123-801%) than initially, ) in 7 NSCLC pts, andin further 9 cases (5 lung, 4 H&N) slightly, between 4% and 17%. In 29
cases GTV (13 lung, 12 H&N and 4 esophagus tumour) and had no significant
difference of GT and GTV1. Relevant tumour shrinkage from 297 (± 684)
cm3 to 88 (±14,6) cm3 was detected in 272 pts. In terms of percentageof the initial volume, the median reduction was 30% (range, 6-87%). PTV,
1030 cm3 (± 832) could be decreased additionally to the deletion of only
potential microscopic disease containing areas resulting in PTV1 of. 497 cm3(±246,5).
Conclusions: Individual evaluation of anatomic changes prior to boost irradiation have significant impact on the complex therapeutical strategy andlead to adapted treatment definition (target dose and volume). The GTV to
GTV1 loss proved to be mainly asymmetric, therefore this simple adaptive
radiotherapy with replanning prior to higher dose delivery is recommended.

Trials: Techniques, dosimetry and
QA

1573 poster
A DOSIMETRY COMPARISON OF FORWARD- AND INVERSEPLANNED IMRT FOR PROSTATE CANCER IN THE CHHIP TRIAL
D. P. Dearnaley1 , O. Naismith2 , G. Sumo3
1

R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Academic Radiotherapy, Sutton, United Kingdom
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Physics , London,
United Kingdom
3
I NSTITUTE OF C ANCER R ESEARCH, Clinical Trials and Statistics Unit
(ICR-CTSU), Section of Clinical Trials, Sutton, United Kingdom
2

Purpose: To compare dose-volume histograms (DVHs) for rectum and bladder using forward- versus inverse-planned IMRT for treatment of prostate cancer in the CHHiP trial.
Materials: CHHiP is a multicentre randomised trial investigating the use of
hypofractionated radiotherapy schedules for treatment of localised prostatecancer. RT treatment employs a complex target volume treated with eithera field-in-field/multi-segment forward-planned beam arrangement or inverseplanned IMRT. 12 UK centres using 6 different treatment planning systems
participated in Parts I and II of the trial, recruiting 457 patients. The 337
moderate risk patients (target volume included seminal vesicles (SV)) wereselected for the comparison. Of these 230 were forward-planned and 107
inverse-planned. A plan assessment form was completed for each patient
treatment plan, which provided a summary of DVH data for normal tissues including rectum and bladder. Calculated dose-volume data were listed against
the trial dose constraints. Patients were paired for the comparison by matching them on (1) rectum and prostate+SV PTV volumes for the rectal dosecomparison; and (2) bladder and prostate-alone PTV volumes for the bladderdose comparison, since these parameters could conceivably affect the relationship between planning method and DVH for these two organs. The majority (88%) of inverse-planned patients were from a centre which used rectal
enemas for prostate radiotherapy, so the rectal volumes for the inverse plans
were generally smaller. The two-sample Wilcoxon rank-sum (Mann-Whitney)
test was used to compare each organ’s DVH between the two planning techniques at the following dose levels: for the rectum 50Gy, 60Gy, 65Gy, 70Gy,
and 74 Gy, and for bladder 50Gy, 60Gy, and 74Gy (these were the doses forwhich dose-volume constraints were specified). Note: The prescribed doseto the prostate PTV was 74Gy in 37 fractions.
Results: The matching exercise resulted in a dataset of 156 and 172 patientsfor the rectum and the bladder analysis respectively. The graphs below show
the results of the two comparisons. Forward-planned patients had significantly larger volumes of their rectum irradiated to doses of 50Gy, 60Gy, 65Gy
and 70Gy compared to inverse-planned patients. However, no difference wasapparent at 74Gy. Forward-planned patients had significantly larger volumesof their bladder irradiated to doses of 50Gy and 60Gy compared to inverseplanned patients. In contrast, inverse-planned patients had significantly larger
volumes of bladder irradiated to 74Gy compared to forward-planned patients.

Conclusions: The use of inverse-planned IMRT significantly reduced the volume of rectum irradiated to doses between 50Gy and 70Gy. Inverse-planningalso reduced the volume of bladder irradiated to 50Gy and 60Gy but resulted
in larger volumes of bladder irradiated to 74Gy compared to forward planning.
1574 poster
A SECURE AND FLEXIBLE ENVIRONMENT FOR ANONYMISING
RADIOTHERAPY DATA IN A CLINICAL DEPARTMENT
G. Bose1 , B. Waters1 , K. Natarajan1 , I. Stronach1 , M. TIffany1 , N. Nundlall1
1
U NIVERSITY H OSPITALS B IRMINGHAM, Medical Physics, Birmingham,
United Kingdom
Purpose: The University Hospitals Birmingham (UHB) NHS Trust Radiotherapy (RT) department participates in routine clinical trials and internal & external RT service developments. In the vast majority of cases the clinical data
used for these purposes needs to be anonymised in accordance with theData Protection Act 1998 and Caldicott Report 1997. As opposed to each of
the clinical applications (spokes) performing anonymisation, this is performed
centrally (hub). In addition to the clinical applications spokes another spoke
connects the hub to a shared file resource from which the anonymised data
can be accessed. DICOM (RT Objects) is the accepted standard for transferring RT patient data and images. Part 15 of the DICOM Standard specifies attributes and sequences that contain patient identifiable data that would need

S 585

be removed or replaced with anonymised attributes. In addition, private andvendor specific attributes need to be removed. Mandatory DICOM attributes
cannot be deleted but have to be replaced with locally unique attributes toensure that they are not link-anonymised. Nevertheless, any anonymised
or link-anonymised data must still be compliant with the destination DICOM
devices e.g. Treatment Planning Systems, treatment delivery systems.
Materials: To meet the hub’s objective two DICOM listeners (Pukka-jTMinstances) were configured to store the original and anonymised data. The
transient patient metadata is stored in databases for audit purposes. To allow
users to define the necessary mapping from original to anonymised identifiers, a GUI was developed using the Java technology. We have extended an
existing in-house Radiology anonymisation application (in use since 2008).
Results: Since implementation, this solution has been used to anonymisedata for more than 16 clinical trials, for service developments (EPID dosimetry) and for training purposes. In all this solution has been used to anonmymise over 100 DICOM RT data sets. This environment ideally lends itself to be extended to forwarding anonymised datasets to designated DICOM
destinations.
Conclusions: We have developed a solution that meets the requirementsof data protection and confidentiality, adopts the DICOM standards and uses
the existing clinical RT and R&D tools used in a typical teaching hospital.
This solution allows multiple applications (spokes) that are DICOM compliant
to send their DICOM data for anonymisation and subsequent analysis andprocessing.
1575 poster
A SURVEY OF THE BENEFITS TO RT PROCESSES AND TECHNIQUES OF PARTICIPATING IN THE CHHIP TRIAL
O. Naismith1 , D. P. Dearnaley2 , E. Hall3
1
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Physics , London,
United Kingdom
2
I NSTITUTE OF C ANCER R ESEARCH & R OYAL M ARSDEN NHS T RUST,
Academic Radiotherapy, Sutton, United Kingdom
3
T HE I NSTITUTE OF C ANCER R ESEARCH, Clinical Trials and Statistics Unit,
Sutton, United Kingdom
Purpose: To assess the benefits of participating in the CHHiP trial on radiotherapy (RT) planning and treatment processes for prostate cancer.
Materials: CHHiP is a multicentre Phase III randomised trial investigating theuse of hypofractionated intensity modulated radiotherapy (IMRT) schedules
for prostate cancer. At the inception of the trial many centres had not yet
implemented IMRT and were using CHHiP as a vehicle to help develop their
IMRT programme. A comprehensive pre-trial quality assurance (QA) program
was set up to ensure adherence to the protocol and provide help to centres.A
questionnaire was sent to all 41 centres participating in CHHIP to gather information on how the trial impacted their departmental RT procedures.
Results: To date 25 centres (61%) have responded. Patient preparation:2
centres changed from treating with empty to full bladders. The trial procedures encouraged almost half of centres to update/ formalise their bladderfilling requirements. Discussions have reinforced the need for better bowel
preparation, and a few centres used CHHiP to pilot the use of rectal enemas and dietary advice. Clinical outlining:50% of centres adapted theirprostate and/or rectum outlining as a result of CHHiP. 40% stated it helped
them with audit or consistency of outlining within their department. IMRT
treatment planning:17 centres used inverse-planned IMRT, 23 used forwardplanned IMRT for CHHiP. Half of the centres using forward-planned IMRT
adopted the technique as routine practice also. Almost half of the centres
using inverse planning used CHHiP to help implement IMRT within their department. A quarter of centres have rolled out IMRT to treat routine prostatepatients as a direct result of CHHiP. 75% of responding centres benefited fromhelp received from the CHHiP QA team, primarily with planning techniques
and optimisation, and networking with other centres using the same treatment planning system or delivery equipment to resolve equipment-specificissues. Dosimetry audit visit:Each centre received a dosimetry audit visit.
The consensus was that, while no major errors were discovered, the measurements gave centres confidence in their treatment plan delivery. Dose
constraints:Most centres were using some form of dose constraints pre-trial,
but 50% modified their practice to reflect the comprehensive set of normal tissue dose constraints specified in the CHHiP trial protocol. Implementation ofchange:Participating in the trial helped develop centres’ IMRT programmes,
reduced resistance to change, and supported evolution of practice and integration into daily departmental practice.
Conclusions: Implementation of the CHHiP trial has shown how a clinical
trial requiring quality-assured high-technology RT delivery can benefit thegeneral standard of RT delivered in participating centres.

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T RIALS : T ECHNIQUES , DOSIMETRY AND QA

T RIALS : T ECHNIQUES , DOSIMETRY AND QA

1576 poster
A TREATMENT PLANNING SYSTEM FOR CONTRAST-ENHANCEDSTEREOTACTIC SYNCHROTRON RADIATION THERAPY
M. Vautrin1 23 , Y. Prezado4 , I. Martínez-Rovira4 5 , P. Deman1 2 , M.
Edouard1 2 , H. Elleaume1 26 , M. Benkebil3 , F. Estève1 26 , J. F. Adam1 26
1
G RENOBLE I NSTITUT DES N EUROSCIENCES , É QUIPE 6, INSERM U836,
Grenoble, France
2
U NIVERSITÉ J OSEPH F OURIER, Grenoble, France
3
D OSISOFT, Cachan, France
4
ID17 M EDICAL B EAMLINE , E UROPEAN S YNCHROTRON R ADIATIONFACILITY
5I NSTITUT DE T ÈCNIQUES E NERGÈTIQUES , U NIVERSITAT P OLITÈCNICA DEC ATALUNYA, Barcelona, Spain
6
C ENTRE H OSPITALIER U NIVERSITAIRE DE G RENOBLE, Grenoble, France
Purpose: Contrast-enhanced stereotactic synchrotron radiation therapy(SSRT) is an innovative technique based on localized dose-enhancement
effects obtained by reinforced photoelectric absorption. Medium energy
monochromatic x-rays (50 -100 keV) are used for irradiating tumors previously
loaded with high-Z elements. In a first approach, the technique is aimed attreating brain tumors with intravenous injections of iodinated contrast agent,
which accumulates specifically in the tumor due to localized blood brain barrier disruption. Preclinical trials of the technique have been performed (1)with promising results. Clinical trials of SSRT are being prepared at the European Synchrotron Radiation Facility (ESRF) (2-3). Patients will be treated
at 80 keV with 10 conformational beams, shaped with Cerrobend blocks (4).
A dedicated treatment planning system (TPS) has been developed for thispurpose, based on the ISOgray commercial TPS (Dosisoft, Cachan, France).
Materials: Specific modifications were performed to the PENELOPE-basedMonte Carlo virtual simulation module: simulation of lower energy photons
and electrons (80 keV and lower), with polarized photons. The synchrotron
beamline geometry was modeled. Dedicated Phase Space Files were built.
Specific materials were also implemented in the patient voxelized geometry,
to consider iodine concentrations in the tumor. Finally a specific computationof absolute doses and associated irradiation times (instead of monitor units)
was implemented. The computation process has been optimized and parallelized. This dedicated TPS was validated with depth dose curves, dose
profiles and absolute dose measurements performed at the ESRF in a watertank and solid water phantoms with and without bone slabs. The measurements were performed with a semiflex ionization chamber (0.125 cm3 ) andgafchromic films.
Results: Computations and measurements in water match within 2 % or 2
mm both in depth and laterally. Computations including a bone slab also
match within 2 % in depth, and 3 % or 3 mm laterally.
Conclusions: The treatment planning system has been validated for dosecomputations in water, in presence of bone slab heterogeneity. The last step
before the first patients scheduled in summer-fall 2011 is to validate this new
tool on some dedicated clinical cases, including the presence of contrast media in the tumor.
1577 poster
A UK-WIDE QUALITY ASSURANCE PROGRAMME FOR AN IMAGEGUIDED RADIOTHERAPY PROSTATE TRIAL
A. Baker1 , O. Naismith2 , P. Mayles3 , H. Mayles3 , H. McNair4 , M. Bidmead2 ,E. Miles5 , D. Dearnaley6
1
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Radiotherapy, Bebington,
Merseyside, United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Physics , London,
United Kingdom
3
C LATTERBRIDGE C ENTRE FOR O NCOLOGY, Physics , Bebington, Merseyside, United Kingdom
4
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiotherapy, Sutton,
United Kingdom
5
M OUNT V ERNON H OSPITAL, National Trials QA Team Co-ordinator,
Northwood Middlesex, United Kingdom
6
R OYAL M ARSDEN NHS F OUNDATION T RUST & T HE I NSTITUTE OF C ANCERR ESEARCH, Academic Radiotherapy, Sutton, United Kingdom
Purpose: Image-guided equipment is now widely available in the UK but thepotential benefits of IGRT for prostate cancer radiotherapy have not beentested in a randomised trial. An IGRT study has been formalised within the
CHHiP trial to act as a conduit to increased uptake of this technology. The
aim of the study is to assess acute and late toxicity associated with IGRT
and determine feasibility of a phase III randomised trial of IGRT in localised
prostate cancer. A QA program was designed for the trial which will guide afuture generic IGRT credentialing program for UK trials, help centres develop
their IGRT processes, and determine issues with imaging data collection.
Materials: Patients in the study were randomised to:(A) no IGRT (standard
margins)(B) IGRT (standard margins)(C) IGRT (reduced margins) Patients inarms B and C were treated using online daily IGRT with either implanted fiducial markers or helical tomotherapy / CT-on-rails. Quality Assurance (QA)TheQA program for the IGRT sub-study complemented pre-trial QA for the main

CHHiP trial. It comprised a process document to collect information on thecentre’s IGRT technique and processes, and measurements to be performedby each centre to assess the accuracy of the imaging and corrections applied(accuracy of couch repositioning and kV/MV isocentre alignments). The calculated shift data for all patients in the IGRT sub-study were documented toassess the feasibility of utilising data from multiple manufacturers’ equipment.
Results: 20 of the original 40 CHHiP centres submitted QA for the IGRT
study. Of these 18 satisfied the QA following feedback. The image-guidance
equipment and procedures used by each centre are listed in the following table. Note: Some centres used different equipment or procedures at different
times during treatment. 7 centres performed automatic couch repositioning,with a zero tolerance. The other 10 centres corrected for any set-up errors≥2mm. 5 centres performed post-correction imaging and 1 post-treatment
imaging. Issues which arose during the QA process included: Should anaction level for post-correction images be applied? Doses reported for different imaging techniques varied significantly in both value and dose descriptor
which made them difficult to interpret and compare. Set up displacements
were not displayed or stored consistently between manufacturers.

Conclusions: The CHHiP IGRT guidelines were successfully adopted by 18
centres. Various different equipment and imaging procedures were used fordaily online prostate localisation within the CHHiP IGRT sub-study. Standardisation is required on imaging methods/associated doses and how theyshould be detailed. Automated data collection presents a significant problem.
1578 poster
ADVANCEMENTS IN PALLIATIVE RADIATION THERAPY: DEVELOPMENT OF AN ONLINE SIMULATION AND TREATMENT DELIVERYPROGRAM
A. Walker1 , J. Müller1 , S. Lang2 , M. Brown3 , A. Imboden1 , C. Winter1 , G.
Studer3
1
U NIVERSITY H OSPITAL Z ÜRICH, Radiation Therapy, Zurich, Switzerland
2
U NIVERSITY H OSPITAL Z ÜRICH, Radiation Physics, Zurich, Switzerland
3
U NIVERSITY H OSPITAL Z ÜRICH, Radiation Oncology, Zurich, Switzerland
Purpose: Advancing clinical practice is resulting in the elimination of our conventional simulator; therefore, a new protocol for palliative radiation therapy
patients was established. The enhanced features of the Varian TrueBeam
allowed us to clinically implement this new program by performing accurate
and efficient online simulation and treatment delivery. Our aim was to identify
the benefits and challenges of this new streamlined practice.
Materials: Patients received a single radiation therapy appointment in which
both simulation and treatment was performed. The patient was set up in thetreatment position and bony anatomy utilized to define the reference point.
The patient separation was measured and the source to skin distance documented. A kV setup image was acquired and the treatment field edge delineated with the option of conformal multi-leaf collimation (MLC). This image
was utilized as the field reference image. An opposed field image was thenacquired and MLC later opposed if necessary. The RadCalc program wasused to calculate daily monitor units for all treatment fields and remaining
data was entered into a record & verification system including setup notes,
daily fractionation doses and imaging protocols. Time data was collected forthe complete simulation and treatment process.
Results: 5 patients have successfully been treated with this new protocol.
Most cases involved bony metastases treated to a dose of 30 Gy in 10 fractions with parallel opposed fields and conformal MLC. Patients received 3-5
static kV images in order to acquire suitable reference information to delineate the treatment fields. The kV image quality was, in general, found to besuperior to the conventional simulator images. On average, we required 45
minutes to perform the entire set-up, simulation, calculation and treatment.
Conclusions: Our initial clinical experience demonstrates that online simulation and treatment is a feasible and proficient solution, replacing our conventional simulation process. We anticipate this new streamlined process will
result in time saving advantages for both patients and departmental workflow;
however, further confirmatory studies are required.

1579 poster
COSTLY NEW TREATMENTS – WHAT SHOULD WE PAY FOR?
A. Haworth12 , M. Grand3 , J. Corry4 , M. Jackson5 , M. Ng6 , T. Kron1 , B.
Burmeister7 , D. Cornes3 , R. Amin3 , G. Duchesne4
1
P ETER M AC C ALLUM C ANCER C ENTRE, Department of Physical Sciences,
East Melbourne, Australia
2
RMIT U NIVERSITY, Applied Sciences, Melbourne, Australia
3
T RANS TASMAN R ADIATION O NCOLOGY G ROUP, Newcastle, Australia
4
P ETER M AC C ALLUM C ANCER C ENTRE, Division of Radiation Oncology ,Melbourne, Australia
5
P RINCE OF WALES H OSPITAL, Department of Radiation Oncology,
Randwick, Australia
6
R ADIATION O NCOLOGY V ICTORIA, Department of Radiation Oncology,
Melbourne, Australia
7
P RINCESS A LEXANDRA H OSPITAL, Department of Radiation Oncology,
Woollongabba/Brisbane, Australia
Purpose: Spiralling costs of radiotherapy due to the introduction of sophisticated imaging and treatment techniques is a major concern worldwide. Whopays for these treatments varies between countries, but what represents bestvalue for money and clinical efficacy is a common issue. The Australian Government, Dept. of Health and Aging has commissioned the Trans-Tasman
Radiation Oncology Group (TROG), a multidisciplinary team of experts withexperience in research and clinical trial management, to develop a genericframework for assessment of new radiation oncology technology and treatments (NROTAT). This paper describes the development of that frameworkand mechanisms for its validation.
Materials: The generic framework was developed to show how publisheddata may be supported by locally acquired data to quantitate the expectedclinical efficacy, cost effectiveness and safety of NROTAT. The framework isundergoing testing through demonstration of the assessment of IMRT and
IGRT. Expert groups, supported by health economists and biostatisticians
have developed protocols for collection of data to populate this generic framework. The tumour sites of nasopharynx, post-prostatectomy and anal canalhave been selected to represent sites that are suitable for treatment with
IMRT. IGRT using fiducial markers and volumetric imaging is undergoing testing in prostate cancer RT. Participating centres were selected so as to include
representation from the wide spectrum of clinical practices.
Results: Existing clinical trial protocols formed the basis for data collection.
Collecting meaningful prospective data in a 12 month time frame in uncommon cancers was a major challenge for two of the IMRT sub-groups. Thisissue was addressed through sub-division of the data collection process: aprospective comparative dosimetric planning study using previously treatedpatient data and a prospective collection of cost utility data. Surrogate endpoints based on DVH analysis from the dosimetric planning studies were developed using previously published clinical evidence for tumour control andlikely toxicity to support clinical efficacy, recognising limitations of these datain the IMRT setting.
Conclusions: Providing high level evidence for funding of new technology
within a limited time frame is virtually impossible. Funding bodies must balance the costs of new technologies with their apparent clinical benefits within
the priority system of a finite health budget. The aim of the proposed framework is to facilitate their ability to make appropriate and timely decisions
based on a limited amount of robust, high quality local data, supported by
the existing literature.
1580 poster
EVALUATION OF A LASER-BASED SURFACE IMAGING SYSTEMFOR IMPROVING THE SETUP ACCURACY IN FRACTIONATED
RADIOTHERAPY
T. Moser1 , K. Schubert2 , G. Sroka-Perez2 , K. Herfarth2 , J. Debus2 , C. P.
Karger1
1
G ERMAN C ANCER R ESEARCH C ENTER (DKFZ), Department of Radiation
Oncology, Heidelberg, Germany
2
U NIV. K LINIKUM H EIDELBERG, Heidelberg, Germany
Purpose: To investigate the suitability of a 3D-laser surface imaging system
in determining inter-fractional setup corrections for different tumour sites inradiotherapy.
Materials: A laser-imaging system (Galaxy, LAP Laser, Lneburg, Germany)
was used to reconstruct 3D patient surfaces with high resolution. The system is mounted at the ceiling of a tomotherapy unit (tomo, HiArt System,
TomoTherapy, Madison, WI, USA). The position of the actual patient model isthen compared with that of a reference model which can be generated eitherwith the system itself at the first fraction or by importing the skin contour of theplanning CT. As a result, a setup correction with 6 degrees of freedom is calculated, which can be applied to the patient. A study was performed to investigate the validity of the proposed setup correction procedure for six different
tumour sites (brain, head & neck, breast, thorax, abdomen, and pelvis). For
each site, 20 patients were included. The setup correction derived from registration of the Megavoltage (MV) CT with the treatment planning CT served asgold standard. After initial setup using skin marks and room lasers, a surface

S 587

image was acquired and the setup corrections were derived. The translationaland rotational corrections proposed by the surface imaging were comparedwith the respective values from the MVCT. In addition, the radial deviation in
space (RAD) was calculated for lateral (LAT), longitudinal (LNG) and vertical(VRT) direction. The study was approved by the local ethics committee andinformed consent was obtained from all patients.
Results: Fig. 1 shows the differences between the setup corrections derived
from the laser system and those from the MVCT for patients with abdominal
and brain tumours, respectively. For the laser system, the reference image
was obtained at the first fraction after the MVCT-based correction. For thetumour site upper abdomen, the deviations between both correction methods
are generally larger than for the brain. The maximum deviation of the medianfrom zero is -2.3 mm (abdomen) and -0.6 mm (brain), respectively. The better
agreement for the brain is attributed to the use of a mask system and the factthat the skull presents a rigid structure.

Conclusions: Surface imaging systems may be used to improve interfractional setup accuracy in radiotherapy. However, the accuracy of the proposedcorrections seems to be strongly dependent on tumour site.
1581 poster
FUNCTIONAL OUTCOME OF PATIENTS WITH IMPENDING CORD
COMPRESSION TREATED BY PALLIATIVE RADIOTHERAPY ALONE
L. O’Sullivan12 , A. Clayton-Lea12 , J. Kenny1 , M. Dunne2 , E. O’Shea12 , O.
McArdle1 , C. Small3 , M. Moriarty1 , C. Collins4 , P. Thirion1
1
S AINT L UKE ’ S H OSPITAL, Department of Radiation Oncology, Dublin,
Ireland Republic of2
C LINICAL T RIALS U NIT, S AINT L UKE ’ S H OSPITAL, Dublin, Ireland Republicof3
G ALWAY U NIVERSITY H OSPITAL, Department of Radiation Oncology,
Galway, Ireland Republic of4
S AINT L UKE ’ S H OSPITAL, Department of Radiology, Dublin, Ireland
Republic ofPurpose: The broader use of MRI in patients (pts) with metastatic bone disease has led to an increase in detection of Impending Malignant Spinal Cord
Compression (IMSCC), defined as an extra-dural malignant process distorting the theca without indenting or displacing the spinal cord. IMSCC pts areusually treated by palliative radiotherapy (P-RT) Our objective is to prospectively evaluate the patient characteristics and outcome of pts treated by P-RT
for IMSCC.
Materials: Pts with IMSCC in our institution are included in an ongoingprospective study, approved by our local ethics committee. The P-RT technical parameters (volume & dose) are left to physician’s preference. All pts
are evaluated prior to P-RT, at weeks 1 and 5, and then 3-monthly. The pts’mobility is evaluated using an in-house 3 point-scale (mobilising unaided; mobilising with aid; bed-bound). P-RT acute and late toxicity, pain and sphincter
control are also documented, using a phone-based assessment.
Results: From September 2007 to February 2010, 28 pts treated for IMSCC
were included in this study. The median age at screening was 56 years (3885). The most common tumour primary sites were breast (7 pts), lung (4pts), renal cell (4 pts) and prostate (3 pts), with a median time from initialdiagnosis to IMSCC of 21 months (n= 25). All pts were diagnosed by full spine
MRI/CT. The IMSCC site was mostly thoracic (12 pts) then lumbar spine (7pts) and cervical, (5 pts). 4 pts had 2 sites of IMSCC. On pre-P-RT physicalexamination, 10 pts had some neurological deficit (data missing for 5 pts).
Most pts were able to walk unaided (16 pts), 8 pts needed a walking aid and4 were bed bound. Pain was found in 100% of pts (n=26). 2 of the 28 pts
presented with bladder incontinence. All pts were treated by P-RT, using astandard 2-dimensional technique and various RT schedules (20 Gy/5 fr in
18 pts, 30 Gy/10 fr in 5 pts). P-RT follow-up demonstrated a spinal-related
neurological deterioration (assessed via the mobility scale) in 4 pts at week
5 (16 remained stable, 1 improved, 5 other pts had died and data missing for2 pts). At the 3 month follow-up mobility was stable (same as baseline) in 6
pts. There was an improvement in pain in 14 pts between initial assessment
and week 1 (1 worsened, 2 remained stable; data missing for 11 pts). There
was an improvement in pain in 15 pts between initial assessment and week 5(1 worsened, 1 remained stable; 5 had died and data were missing for 6 pts).
The median survival of pts with IMSCC was 4.2 months (127 days) from dateof screening.
Conclusions: A large proportion of pts with IMSCC present with neurological deficit despite reassuring radiology. The functional outcome of pts with

S 588U NDERGRADUATE , POSTGRADUATE AND CONTINUOUS EDUCATIONU NDERGRADUATE , POSTGRADUATE AND CONTINUOUS EDUCATIONIMSCC is poor with 81% of pts developing neurological deficit (assessed by
the mobility scale) despite palliative RT. In addition, pts with IMSCC havepoor survival. This increasing patient category (IMSCC) deserves dedicatedclinical research.
1582 poster
NODAL RESPONSE TO CHEMORADIOTHERAPY IN OESOPHAGEALCANCER
M. Coffey1 , A. Cobbe1
1

T RINITY C OLLEGE D UBLIN, Discipline of Radiation Therapy, School of
Medicine, Dublin, Ireland Republic ofPurpose: The use of multimodality therapy in the form of neoadjuvant
chemoradiotherapy followed by radical surgery is increasingly being considered as a standard treatment for oesophageal cancer. This method of treatment has been shown to be associated with increased survival but also increased postoperative complications in addition to delaying surgery. New evidence shows that achieving a node negative status as opposed to a complete
pathological response of the tumour from the neoadjuvant treatment is associated with increased survivial. However only a small percentage of patientsachieve node negative status and the identification of factors that predict this
response would be of considerable benefit.
Materials: An analysis of an anonymised gastroesophageal database was
performed. The preditive values of the following patient and tumour-related
factors were considered: sex, smoking history, alcohol history, presence ofBarrett’s Oesophagus, age at diagnosis, body mass index (BMI), histologicaltype, site, degree of differentiation and clinical stage. Microsoft Office Excel
2007 software was used to create descriptive tables presenting the association of the patient and tumour related factors with the response of the nodal
diseaseResults: 42 patients underwent neoadjuvant treatment consisting of
chemotherapy (5 Fluorouracil and Cisplatin: 6 day regimen) and radiotherapy(40Gy in 15 fractions) between January 2004 and December 2008. 4 patients(9.5%) achieved a node negative status, 25 (59.5%) had no nodal response
and 13 (31%) nodal disease progression. Females were associated with abetter nodal response as were patients who had not been diagnosed withBarrett’s Oesophagus. Adenocarcinomas, tumours of the oesophagogastricjunction and more poorly differentiated tumours were associated with a worse
nodal response. Smoking history, alcohol history, age, BMI and stage were
not predictive of response.
Conclusions: Females were more associated with achieving a node negative status after chemoradiotherapy. There was an association between poor
response and Barrett’s Oesophagus, adenocarcinomas and tumours at theoesophagogastric junction. However the independence of the factors is unclear. The differentiation of the tumour was also predicftive of response. As
the group of patients achieving a good response was very small a further
analysis of a large cohort of patients would provide more conclusive results.
1583 poster

STREAMLINING IMRT QA BETWEEN UK RANDOMISED MULTICENTRE TRIALS
E. Miles1 , E. Wells2 , D. Bernstein2 , C. Clark3 , Y. M. Tsang1 , L. Ciurlionis1 ,E. Aird4
1
M OUNT V ERNON H OSPITAL, Radiotherapy Physics, Northwood Middlesex,
United Kingdom
2
T HE R OYAL M ARSDEN NHS F OUNDATION T RUST, Radiotherapy Physics,
London, United Kingdom
3
S T. L UKE ’ S C ANCER C ENTRE R OYAL S URREY C OUNTY H OSP, Radiotherapy Physics, Guildford, United Kingdom
4
M OUNT V ERNON H OSPITAL, Medical Physics, Northwood Middlesex,
United Kingdom
Purpose: The National Radiotherapy Trials Quality Assurance (RTTQA)
group has implemented a 9-step IMRT credentialing programme for all NCRI
portfolio clinical trials employing IMRT techniques. With increasing numbersof IMRT trials in the UK it is of priority to reduce the workload and simplify theprocess for centres joining multiple trials. Current credentialing is on a trial bytrial basis, the aim of this study is to investigate the feasibility of moving fromtrial specific to anatomical site credentialing.
Materials: Each of the 9 steps of the programme have been re-evaluatedaccording to anatomical site and the duration of their validity has been considered. The complexity of IMRT planning and delivery has been investigatedwith a view to reducing the number of dosimetry audit visits needed. All plans
have been generated using the Varian Eclipse TPS. This study investigatesusing the average leaf pair opening parameter (ALPO) to quantify the level ofmodulation in plans from a range of UK multicentre IMRT trials.
Results: The TPS test, used to check the commissioning of the treatment
planning system, is applicable to all anatomical sites and need only be done
once (subject to equipment changes and upgrades), as does the electronictransfer of data. Outlining and planning exercises and the trial specific questionnaire should be completed for each trial. The process document submis-

sion must still be considered on a case by case basis. For the dosimetry
audit, cross-referencing has been made between anatomical sites. This has
resulted in grading of sites according to complexity of planning and delivery.
Sites with more complex modulation can reduce the QA burden for less complex sites. Initial results, consisting of 4 plans from the ART DECO (head andneck, H&N), COSTAR (H&N), PARSPORT (H&N), IMPORT HIGH (breast)and CHHIP (prostate) trials have yielded mean ALPO±SD of 2.1±0.7cm,
2.4±0.6cm, 1.7±0.6cm, 2.1±0.4cm and 3.9±0.5cm respectively. These indicate that the plans for the prostate trial have the least modulation where as
the H&N and breast plans have similar levels of complexity. In recent months
dosimetry audits carried out at investigator sites for the COSTAR head & necktrial have reduced the number of site visits required for the IMPORT HIGH
breast trial. This was a significant reduction in workload, and future combined
audits have been planned. Furthermore credentialing should be assessed ateach centre for its validity after 3 years.
Conclusions: The QA burden on centres contributing to multiple trials has,in the past, been heavy. This streamlining approach takes into account previous QA programmes and reduces the number of tests and measurements
appropriately whilst still maintaining QA and trial standards. It is hoped toextend this approach to the international setting taking into account QA done
for clinical trials in other countries thereby reducing unnecessary QA.
1584 poster
THE VORTEX TRIAL - QA FOR TARGET VOLUME DELINEATION OF
EXTREMITY SOFT TISSUE SARCOMA
E. Cowie1
1
M OUNT V ERNON H OSPITAL, RadiotherapyPhysics, Northwood Middlesex,
United Kingdom
Purpose: The VORTEX trial is a multicentre phase 3 randomised trial ofvolume of post-operative radiotherapy given to adult patients with extremity
soft tissue sarcoma. The objective of the trial is to assess if a reduced volumeof post-operative radiotherapy increases limb function without compromisinglocal control. There is little data addressing the definition of target volume in
the field of extremity soft tissue sarcoma in adult patients. Aprogramme ofpre-trial quality assurance (QA) was devised to include a voluming exercise
to address potential inconsistencies and lack of consensus surrounding limb
sarcoma definition of volumes.
Materials: Instructions on target volume delineation were detailed in the trial
protocol and a voluming exercise was designed and completed by all centreswishing to enter the trial. Image sets of the pre-operative MRI and postoperative planning CT were sent to all participants for importing and delineation. The completed planning volumes were collected electronically andimported onto same CT image set for evaluation. VODCA and SHERRI aresoftware analysis tools that allow structures to be reviewed and analysed
within a single platform.
Results: Eighteen centres have currently entered Vortex with twenty-two volume exercises submitted. Three exercises were re-submitted due to being
clinically unacceptable. The GTV proved to be the largest cause of discrepancy between centres with GTV dimensions in the superior/inferior plane:
Average length = 96mm ranging from 105mm up to 135mm Average inferior
boundary = 43mm ranging from 5mm up to 100mm Average superior boundary = 53mm ranging from 35mm up to 100mm A second discrepancy was
the 20mm axial expansion of the CTV. Nineteen of the twenty-two centres
deviated slightly from protocol.
Conclusions: The outlining exercise highlighted the different approaches
taken to volume delineation for extremity soft tissue sarcomas in adults. As
a result, a clinical focus group has been formed to provide guidance on target volume delineation within the trial and an outlining workshop for all trial
participants is to be organised to address the lack of consensus on volumes
for this group of patients. Ultimately, this will ensure that clinical observations
reflect differences in the randomised schedules rather than departures fromtrial protocol.

Undergraduate, postgraduate andcontinuous education
1585 poster
A COMPARISON OF ACTIVE AND PASSIVE RADIATION DETECTORS WITHIN A 15MV LINEAR ACCELERATOR BUNKER
B. Medford1 , M. Knight1 , D. Bonnett1
1
K ENT O NCOLOGY C ENTRE, Department of Medical Physics and Radiation
Safety, Maidstone, Kent, United Kingdom
Purpose: The production of high energy x-rays gives rise to a complex radiation environment in and around a linac bunker. The aim of this investigation

S 589

was to compare both active and passive radiation detectors at various positions within a 15MV linac bunker.
Materials: The active detectors used were an ionisation chamber (SmartION 2120) for photons and a boron tri-fluride proportional counter (NM2B)
for neutrons. These were compared with passive 7 LiF(Mg, Cu, P) thermoluminescent detectors (TLDs) and neutron sensitive poly-ally diglycol carbonate
detectors (PADCs). Measurements were taken at 8 different positions in the
bunker using both active and passive detectors. In order to account for the
non-uniformity in the energy and polar response of the neutron detectors andconsequently obtain more accurate measurements, the angular and energy
spectrum of the incident radiation was characterised at the measurement positions. This was achieved by modelling the linac bunker using Monte Carlo(MCNPX) techniques and approximating the linac as a pure neutron source
in a 10cm diameter sphere of tungsten.
Results: The SmartION produced higher readings than the TLDs in the linac
maze (173 nSv.MU-1 and 119 nSv.MU-1 respectively at the top of the maze),but gave comparable readings in the treatment room where higher readings
were expected (278 nSv.MU-1 and 297 nSv.MU-1 at 3m from the linac head).
For neutron measurements, there was considerable variation between active
and passive measurements. This variation illustrates the difficulty in obtaining
reliable neutron measurements in mixed pulsed photon and neutron fields inside the linac bunker. The NM2B was shown to be unreliable in the presenceof pulsed photon fields and should not be used in the treatment room; however down the maze the NM2B provided a reliable estimate of H*(10). Theenergy and angular response corrected PADC readings were not affected by
the pulsed nature of the radiation in the treatment room and consequently
provided a more reliable estimate than the NM2B readings at this location.
Conclusions: This project confirmed that in order to characterise the radiation environment in and around a linac bunker it is necessary to use bothactive and passive detectors. Active detectors have been found to provide
instantaneous and reliable readings within the maze, while passive detectors produced more reliable readings in the treatment room in comparison to
the active detectors. For neutron measurements, it is beneficial to have someknowledge of the neutron energy spectrum to reliably estimate neutron doses
in and around a linac bunker.

and professional studies (105-110 ECTS), free-choice studies (10-15 ECTS),
practical training (75 ECTS) and bachelor’s thesis 15 (ECTS). The basic andprofessional studies deal with patient care and the use of radiation, x-ray,nuclear medicine, ultrasound and magnetic resonance examinations and radiation therapy. Communicative studies (Finnish, Swedish and English), research and development studies, as research and statistics, bachelor’s thesis,
and the studies concerning basic skills in health care are also included to theprogramme. Graduated students are certified as radiographers. The data,consisting of two different curricula, was analysed by content analysis.
Results: External radiation therapy and brachytherapy related subjects include radiation biology and radiation physics, safe use of radiation and radiation protection, oncology and pharmacology, treatment planning, radiation
therapy equipment, patient and treatment set ups, and delivering radiation
therapies. Other subjects are as first aid, microbiology, anatomy and physiology, nutrition, rehabilitation and patient care. Main learning methods are
study visits, case studies and group working, literature searches and essays,learning diaries, discussion in virtual learning environment and clinical practise. The main outcome competences are caring and advising competence
in radiography and radiation therapy, methodological competence in radiography and radiation therapy, quality assurance competence in radiography
and radiation therapy, and competence in radiation safety. Collaboration withpartners from the clinical side consists of expert lessons and students participation to the clinical research and developmental work.
Conclusions: After graduation the RTT is able to work in an interprofessionalteam in collaboration with radiation oncologists and clinical physicists. RTT isalso able to take part in radiotherapy treatment planning and use radiotherapy
equipment safely. RTT has through understanding of a radiotherapy simulator
and patient set ups. RTT can also support patients and their family members.
She or he takes into account changes in the patient’s condition and advises
the patient in the management of radiation side effects.

1586 poster

1

EDUCATION AND TRAINING OF THE RADIATION ONCOLOGYPHYSICS PROFESSION WITHIN AUSTRALASIA
L. K. Yuen1
1
T HE W.P. H OLMAN C LINIC, L AUNCESTON G ENERAL H OSPITA, Radiation
Oncology, Launceston, Tasmania, Australia
Purpose: The aging population in Australasia is resulting in growing demandfor Radiation Oncology. In Australia alone the number of cancer treatment
centres has almost doubled in the last 15 years. High quality, well organised
training and education of medical physicists is thus of fundamental importance to support this growth; particularly since the number of registrar positions in the work force is increasing substantially faster than the number ofexperienced physicists. The poster will focus primarily on the development
pathway of Medical Physicists within Australasia, highlighting tertiary courses
and continuous education offered by the Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM). The program established for
Medical Physics registrars in Australasia is strongly influenced by international guidelines, such as IAEA (TCS-37) and the IAEA/RCA Expert Steering Group RAS6038. Currently, five Universities in Australia and two in New
Zealand offer accredited degree programmes in medical physics. The poster
will outline tertiary courses offered in the region, highlighting the number ofgraduates and its relationship to a trainee positions within the workforce. The
ACPSEM has implemented the Training, Education and Accreditation Program (TEAP) in the disciplines of Radiation Oncology, Radiology and Nuclear
Medicine to train graduates/ junior physicists both clinically and academicallyto an international standard. Furthermore, Continuing Professional Development (CPD) has also been encouraged to ensure accredited medical physicists maintain their professional standards to state-of-the-art levels.
Materials:
Results:
Conclusions:
1587 poster
RTT´S COMPETENCES ACHIEVED IN UNDERGRADUATE CURRICULA IN FINLAND
A. L. Jussila1 , A. Kangas2
1
O ULU U NIVERSITY OF A PPLIED S CIENCES, Oulu, Finland
2
M ETROPOLIA U NIVERSITY OF A PPLIED S CIENCES, Helsinki, Finland
Purpose: To describe the curricula of joined radiography and radiotherapy
undergraduate educations in two different applied universities in Finland. The
perspective is to clarify the contents, teaching and learning methods, learning
outcomes, and collaboration with partners from the clinical side.
Materials: The degree programme (210 ECTS) consists of basic studies

1588 poster
THE EFFECT OF CISPLATIN, CARBOPLATIN AND RADIATION ON
PEO AND SKOV-3 OVARIAN CANCER CELLS
A. Bangiri1 , J. C. Jeynes1 , K. Kirkby1
U NIVERSITY OF S URREY, Guildford, United Kingdom

Purpose: The aim of this project was to compare the effects of radiationand two chemotherapy drugs, carboplatin and cisplatin, either singularly or in
combination, on two ovarian cancer cell lines, PEO and SKOV-3.
Materials: Two established ovarian cancer cell lines were treated with various concentrations of cisplatin and carboplatin ranging between 0-10000 nM
and 0-20,000 nM respectively. The cell lines were also irradiated with different doses of 300 kVp X-rays. Survival curves were produced using two
techniques, the clonogenic assay and the microtitration (MTT) assay. The
clonogenic assay shows the reproductive ability of the cells, through the production of colonies. The MTT assay portrays the metabolic activity of thecells through the reduction of a yellow water-soluble dye to a purple formazan
product.
Results: The cisplatin was shown to be far more toxic than carboplatinwith both assays, with surviving fractions of 19.0±4.6% for the PEO and
15.0±2.0% for the SKOV-3 cells with the clonogenic assay for 1000 nM.
For 1000 nM of carboplatin the corresponding results were 49.9±5.2% and40.0±8.0%. The results from the MTT assay also showed that both cell lines
grew resistant to both drugs for concentrations higher than 1000 nM. For
carboplatin and the PEO cells the results were equivalent for the clonogenic
assay but for the SKOV-3 the surviving fraction decreased further for concentrations higher than 1000 nM. Concentrations of cisplatin up to 1000 nM wereused for the clonogenic assay, so no comparison could be made with the results of the MTT assay. When the cells were irradiated, the MTT assay results
could not distinguish which cell line was more radiosensitive, but the clonogenic assay showed clearly that the SKOV-3 are more resistant to radiation
than the PEO. When carboplatin (250 nM) was used together with radiation
for the PEO cells, the surviving fraction was smaller, by approximately 10%,compared to that from radiation alone.
Conclusions: Cisplatin, even at lower concentrations, was shown to be more
toxic than carboplatin for both cell lines. The MTT assay showed that for concentrations higher than 1000 nM, the SKOV-3 and PEO cells grow resistant toboth drugs. The results were similar only for carboplatin and the PEO cells.
The SKOV-3 cells were found to be more radioresistant than the PEO cells.
The surviving fractions for the PEO cells were further reduced when carboplatin was used in conjunction with radiation. The MTT assay can be used iftime is an issue and accurate results on surviving fractions are not needed.
The clonogenic assay remains the method of choice.
1589 poster
THE EFFECTIVENESS OF THE TIGER PROGRAMME IN CONJUNCTION WITH CONTOURING GUIDELINES IN REDUCINGINTER-OBSERVER VARIABILITY, AMONG RADIATION THERAPYS 590U NDERGRADUATE , POSTGRADUATE AND CONTINUOUS EDUCATIONSTUDENTS IN CONTOURING THE PROSTATE SITE.
A. Monaghan1 , M. Broderick2 , M. Coffey2 , M. Leech2
1

T RINITY C ENTRE FOR H EALTH S CIENCES, Discipline of Radiation Therapy,
Dublin 8, Ireland Republic of2
TCD D IVISION OF R ADIATION T HERAPY, Dublin, Ireland Republic ofPurpose: The study aimed to evaluate the inter-observer variation with respect to a reference model, among 4th year radiation therapy students, incontouring the prostate, bladder and rectum.
Materials: An intervention was designed by the lead investigator to reduce
inter-observer variation in contouring the prostate site. The effectiveness of
the intervention was measured using changes in contour variation, with respect to a reference model, among intervention participants compared to acontrol group.
Results: Improvements in the CTV and bladder contours were observed in
the intervention group, with respect to the model, following the intervention.
Inversely, disimprovements in the CTV and bladder were observed in the control group, from contour session 1 to contour session 2. Both control and intervention groups demonstrated disimprovement in the rectum contours andimprovement in the CTV superior/inferior limit distances. Resulting contourbased DVHs suggested a substantial impact on the percentage OAR volume
receiving therapeutic dose levels, as a consequence of contour variation
Conclusions: Given the substantial intra-observer variation in this study, limited significant conclusions can be drawn as to the effectiveness of the intervention, though some trends in the data are promising and warrant further
study. Notably, both control and intervention groups overestimated the CTV
volume and underestimated the bladder and rectum volumes, with respect tothe model.

S 591

AUTHOR INDEX

Author index
A J., 825
A P., 825
Aagaard T., 1077
Abbasinejad Enger S., 682, 728
Abdeen G., 677
Abed J., 1031
Abolfathi P., 107
Abraha I., 1034
Abramyuk A., 890
Abu Jawad J., 1254
Accettura C., 1003
Achanta P., 1515
Achari R., 980, 1469
Ackerman N., 1103
Adaimi Hernandez P., 608
Adam J. F., 1576
Adamczyk M., 1200
Adamczyk S., 1380, 1404
Adamiak E., 1200
Adams E., 1162, 1433
Adamska K., 978
Adriana P., 1003
Adrich P., 31, 1387
Aebersold D. M., 610, 823, 893, 902
Aerts H., 68, 168, 471, 474
af Wetterstedt S., 1559
Afsharpour H., 81, 156
Afshin R., 764
Agarwal J. P., 133, 293, 489
Agergaard S., 460, 1273
ages D., 964
Aghili M., 1366
Agnese D., 898
Agostinelli S., 6, 24, 32, 598, 681, 898, 909
Agoston P., 230
Aguayo Martos M., 1008, 1413
Aguilar C., 1021
Aguilar C. R., 810
Aguirre E., 747
Agustí R., 1492
Ahlgren G., 343
Ahmad R., 1201
Ahmad S., 1051
Ahmed M., 1334
Ahn S. D., 789, 962
Ahnesjö A., 682, 1252
Ahunbay E., 175
Aiani A., 1409
Aibe N., 778
Aird E., 123, 182, 395, 486, 1583
Aitken A., 475, 1027, 1257
Aitken K., 1026
Ajithkumar T. V., 894
Ajraoui S., 1290
Akima R., 777
Akinlade B., 661
Akins R., 85, 228, 611, 620, 621, 717, 718,
904, 942, 943, 956
Al Ahmed B., 186
Al Khawaja M. S., 1212
Al Mousa A., 820, 928
Al Safadi N., 186
Al-Booz H., 298
Al-Ghamdi S., 186
Al-Lozi R., 1512
Al-Mousa A., 677
Al-Qaisieh B., 200, 691
AL-Sulaiti L., 966
Alanin M. C., 515
Alayrach M. E., 524
Alba F., 663, 842, 1350
Alber M., 262, 506, 558, 1168, 1312
Albitskiy I., 703, 905
Albregts M., 1195
Albrich D., 261
Alcalde J., 289
Aldridge S., 657, 684
Alejo Luque L., 1106
Aleknavicius E., 612, 624, 720, 774, 819, 1017
Alessandra F. P., 1307
Alexander A., 438
Alexander E., 1249
Alfonsi M., 135
Ali E., 378
Ali W. I., 1070

Ali Z., 941
Alice F., 1400
Alizadeh M., 1044, 1074
Alkhatib H., 238, 426
Allahverdi M., 932, 1111, 1366, 1393, 1563
Allahverdi Pourfallah T., 831
Allen P. K., 233
Allinson N., 1122
Allison R., 884
Almadori G., 847
Almeida D., 1062
Alongi F., 870, 921
Alonso J. R., 562
Alonso Redondo E., 627, 629
Alsner J., 367
Altena W., 1184
Alterio D., 1192
Althof V., 214, 527, 1184, 1325
Aluwini S., 711
Alvarez A., 35
Alvarez E., 35, 38, 39
Alvarez M. A. G., 428
Alves L., 1075
Amgarou K., 422, 1099, 1104, 1497, 1500
Amichetti M., 277
Amin M., 1022
Amin R., 1579
Ammendolia I., 675
amoroso V., 739
Amos R., 233
Anacak Y., 541
Anand V., 648, 1091
Anaxagoras T., 1122
Anbumani S., 1138
Anderluh F., 957, 1068
Andersen A., 1213
Andersen C. E., 70, 384, 433
Andersen E., 136, 515
Andersen E. K. F., 323
Andersen K., 403, 1258
Andersen L. J., 136
Andersen M. H., 1509
Andersen M. R., 1292
Anderson N., 450, 1232, 1414
Andrade Alvarez B., 1100, 1462
Andrade B., 1088, 1365, 1493
Andrade G., 1489
Andrea P., 594
Andrejczuk A., 725
Andreoli S., 1131
Andres I., 1008, 1413
Andrew K., 113
Angelo P., 1461
Angelovska N., 934
Angulo Pain M. E., 671
Anile C., 842, 845, 846, 997
Anna S. T., 706
Ansbacher W., 77, 625
Anscher M., 1251
Anselmo P., 1002
Ansorge O., 930
Antognoni P., 861, 1233, 1245, 1264
Antoine C., 1124
Antonadou T., 855
Antonini P., 733
Antunac K., 771
Aoki M., 1018, 1038, 1039
Aoyama H., 1235
Aoyama N., 777
Apardian Manougian R., 698, 705
Apicella G., 37, 842
Appelt A. L., 179
Applegate K., 1403
Apte A., 99, 134, 397, 506
Araceli G. A., 423, 1113
Aragno D., 1170, 1353, 1394
Araújo M., 1454, 1555
Arbea Moreno L., 224
Arcangeli S., 1539
Arce P., 420, 1428, 1498
Archambault L., 372, 431
Arcidiacono F., 1034
Ardu V., 1332
Arenas Prat M., 1008, 1413
Arends M., 1545, 1550

Ares C., 521, 977
Argentini R., 1353
Arias F., 185
Aristei C., 749, 762, 768, 889, 1034, 1060,
1370, 1378
Aristu J. J., 289
Ariyaratne H., 1279
Armour M., 141
Armstrong D., 750, 767
Arnaiz M. D. M., 895
Arnalte R., 965
Arnetta G., 597
Arnold A., 823
Arraras J. I., 185, 760
Arribas L. A., 290, 623
Arriola N., 810, 1021
Arráns R., 428
Arthur D., 628
Aryaee M., 944, 979
Asai Y., 1364
Asakhin S., 888
Ashley S., 1011
Ashman J., 13
Asin G., 185, 760
Aslay I. S., 616, 1199
Asrari F., 750, 767
Asselain B., 307
Assmann W., 390
Astner S., 1160
Aswathanarayana N., 844
Athanasiou E., 757
Atkins H., 828
Atkinson C., 496
Atkocius V., 612, 624, 651, 774
Atyeo J., 1510
Au P., 1271
Aubin S., 698, 705, 707
Aubineau-Lanièce I., 688
Augelli B. G., 588
Auperin A., 192
Aupov F., 787
Ausma A. H., 1545, 1550
Autorino R., 846, 847, 997
Autret D., 1569
Aversa S., 906
Avery A. M., 731
Awan A., 1305
Axelsson S., 1417
Ayadi M., 1294
AYATA H., 1443
Aydogan B., 1305
Azario L., 294, 1461
Aznar M., 181, 473, 908, 1531, 1558
Azuma Y., 1235
Azzeroni R., 256, 1312, 1332, 1517
B. M. K., 1056
Bacigalupo A., 816, 909
Bahadur A. K., 862
Bahadur Y., 665, 1079
Bahary J. P., 536, 1044
Bahoric B., 222, 740, 1242
Bainbridge A., 1272
Baio A., 835
Baiocchi C., 900
Bajon T., 1236, 1358
Bak B., 565
Bakardjiev S., 885
Baker A., 892, 1577
Baker C., 97, 180, 1147
Baker M., 1258, 1507
Baker-James S., 1143
Bakkum-Gamez J., 41
Bako M., 664
Bal M., 324, 412
Balcet V., 1327
Baldissera A., 587
Balducci M., 842, 845, 846, 997
Baldwin K., 110
Balestrazzi E., 294
Ballerini G., 737, 1307
Ballesta A., 733
Ballester F., 421, 666, 686, 689, 1097
Baltas D., 42, 157, 402, 421, 687, 1084

S 592Bampi R., 669
Banci Buonamici F., 277
Bandera L., 739, 907
Banerjee S., 297
Bangiri A., 1588
Bangma C., 711
Bangsgaard J. P., 1241, 1309, 1321, 1558
Banipal R. P. S., 876
Bankousli I., 855
Bannon E., 922, 1089
Banuelos G., 810, 1021
Banzi M. C., 1071
Baquedano Baquedano J. E., 747
Bar-Deroma R., 1155
Barazzuol L., 940
Barbara P. J., 706, 924
Barbera F., 952
Barbiere J., 1246
Barbieri D., 739
Barbieri E., 675, 811
Barbieri P., 1233, 1245, 1264
Barentsz J., 366
Bargotra R., 968
Barillot I., 152, 800
Barkwith A., 950
Barnett G., 516
Barney B., 34, 41
Baroni G., 174, 532, 1192, 1218, 1276
Barquero R., 102, 1104, 1497, 1499
Barra S., 499, 669, 909, 1530
Barrett J., 513
Bartelink H., 207, 309
Bartkowiak D., 125
Bartlett F., 746
Baruah J. D., 862
Bas H., 1306, 1348, 1524
Basilico F., 1409
Bassignani M., 1251
Bassinet C., 1127, 1129, 1130
Bastiani P., 277
Bastos A., 1169
Batalla A., 1385
Batel V., 1371
Batista V., 1357
Battachraji S., 825
Battermann J. J., 259, 1016, 1037
Battistoni G., 437
Batumalai V., 113
Baum M., 311
BAUMANN M., 1129
Baumann M., 126, 234, 494, 563, 1127, 1130
Baumert B., 182
Bayankin S., 1557
Bayir-Angin G., 916
Bayliss Y., 1150
Bayouth J., 441, 1533
Bazalova M., 434, 1103
Beardmore C., 513
Beauchamp C., 13
Beauchemin M. C., 302
Beaulieu F., 417
Beaulieu L., 55, 81, 108, 154, 156, 372, 386,
417, 431, 682, 698, 705, 726,
728, 1114
Beaumont S., 1569
Beavis A., 513, 690
Beddar S., 372, 431
Bedford J., 74, 1313, 1320, 1334, 1434
Bedini N., 727
Begnozzi L., 1549
Behrendt K., 719, 725, 1019
Behrens C. F., 419, 433, 1268, 1386, 1505
Beierholm A. R., 433
Beiki-Ardakani A., 1031
Beketic-Oreskovic L., 770
Bekhuis E., 1184
Bel A., 328, 531, 704
Belardi A., 40
Belderbos J., 100, 275, 391, 887
Belderbos J. S. A., 101, 217, 268, 276, 1556
Beldì D., 37
Belgioia L., 6, 898
Belka C., 970, 981, 992
Bellavita R., 889, 1034, 1378
Bellesi L., 24, 26, 27, 30, 596
Bellyei S., 1523, 1551
Belton R., 1363

AUTHOR INDEX
Beltramo G., 976, 1525, 1527, 1534
Beltran M., 1340
Ben Yosef R., 1251
Ben-Ayun M., 782
Ben-david M., 782
Benassi M., 26, 27, 30
Benasso M., 816
Benazzo M., 835
Bendl R., 1196, 1211, 1287–1289
Benedek H., 1329
Bengiat H., 1300
Bengtsson Scherman J., 1241
Benhdech Y., 1569
Beni R., 585
Benkebil M., 1576
Bensadoun R. J., 656
Benstead K., 513, 557
Bentiez P., 618
Bentzen J., 865
Bentzen L., 485, 506, 1186, 1285
Bentzen S., 181, 326
Berardi G., 500
Berberat J., 815
BERBEROGLU K., 1306
Berbée M., 1256
Berenguer R., 1008, 1389, 1413
Berg M., 1105
Bergantin A., 960, 1525, 1527, 1534
Berger A., 656
Bergmann H., 1215
Bergstrand E. S., 1083
Berkovic K., 1254
Bermúdez M., 371
Bernabei A., 1450
Bernchou U., 460
Bernhard M., 1118
Bernshaw D., 633
Bernstein D., 1338, 1583
Bernstein M., 944, 979
Berresford J., 1375
Berriolo-Riedinger A., 795
Berry I., 333
Berstein D., 1260
Bertelsen A., 326, 912, 1316
Berthelsen A. K., 181, 473, 985
Bertino G., 835
Bertolino N., 437
Bertoni F., 277, 478, 499, 749, 861, 1179,
1233, 1245, 1264, 1519
Bertrand D., 1182
Betgen A., 476, 996
Betti M., 1352, 1353
Beukema J., 169, 325
Beyer G., 1470
Beyreuther E., 563
Bhalavat R., 293
Bhalla N., 1308
Bhanage A., 980
Bhandare N., 639
Bhangale J., 980
Bhaskaran S., 647
Bhatnagar A. R., 619
Bhide S., 519
Bhuvanendran N., 814
Bialas B., 662, 725
Bianchi L. C., 953, 960, 976, 1525, 1527
bianchi L. C., 1534
Białas B., 617, 719
Bidmead M., 475, 989, 1026, 1027, 1270,
1577
Bieleda G., 734
Bielicki K., 780
Biemans-vanKastel L., 1411
Bignardi M., 481
Bijker N., 207
Bijl H. P., 184, 411, 1356
Biju G., 1508
Bilimagga R., 609, 825, 1138
bin Kassim I., 1343
Binbin W., 98
Bini V., 768
Binotti L., 1179
Birkfellner W., 469, 1215
Birkner M., 1545
Bisognin R., 587
Björk-Eriksson T., 181
Black E., 822

Blake L., 1416
Blake P. R., 545, 1311
Blakeney S., 113
Blanchard N., 795
Blanchard P., 43
Blanco J. A., 35
Blank E., 590
Blasi M. A., 294
Blasiak B., 351, 724, 734, 1478
Blasiak-Wal I., 449
Blesing C., 930, 950
Bloch C., 1215
Bloch-Larsen L., 111
Block G., 657
Bloemen- van Gurp E., 300, 1208, 1256
Blomquist E., 1330
Blumstein N., 893
Bly R., 1543
Blythe K., 1338
Bocci A., 428
Boda K., 1495
Bodis S., 815
Boeje C. R., 131
Boejen A., 111
Boersma L., 96, 1277
Bogaerts J., 207
Bogdan V., 278
Bogner L., 451
Bogovalova N., 1518
Bogusz-Czerniewicz M., 359
Bohlen G., 1251
Bohoslavsky R., 413
Boike T., 477
Boisserie G., 1127
boissonade O., 656
Bokhari S. M. A., 765
Bokrantz R., 252
Bol G., 796
BOLDO E., 589, 591, 603, 604
Bolla M., 335
Bolognesi A., 753
Bolognini D., 1409
Bomanji J., 958, 982
Bondar L., 1201
Bonetta A., 499, 749
Bonetti B., 907
Bonetto E. M., 499
Bonfanti P., 1525, 1527, 1534
Boni L., 1179
Bonner P., 166
Bonnetain F., 178, 795
Bonnett D., 1585
Bonomo P., 847, 869, 1323
Bonora M., 1012
Bonsignore F., 1372
Bonucci I., 899, 1072, 1073
Boot H., 165
Bootsma G., 274
Borasi G., 597
Borasio P., 1409
Bordage M. C., 1188
Bordon E., 788
Bordonaro L., 675
Borges C., 1531
Borges F., 1169
Borghesi M., 1425
Borghetti P., 907, 952
Boris A., 594
Borisov N. M., 1518
Born E., 893, 902, 1399
Bornfeld N., 1390
Borren A., 66
Borroni M., 678, 727
Bortfeld T., 196
Bortolus R., 499
Bosch W., 1298
Bose G., 1574
Boso C., 906
Bossi A., 265
Bossi-Zanetti I., 1012
Boston S., 1015
Botella S., 39
Boterberg T., 837
Botti A., 408, 891, 1161
Botwood A., 1308
Boualga K., 1043
Bouché A., 28, 589, 591, 593, 603, 604

S 593

AUTHOR INDEXBouché-Babiloni A., 21
Boudreau C., 1074
Boukour Y., 137, 466
Bourel P., 1479
Bourgier C., 585
Bourhis J., 45, 493, 514, 567
Bourque A., 726
Bouzeya N., 458
Bouzid K., 864
Bove G., 1535, 1536
Bowden S., 879
Bownes P., 650, 679, 691
Boye D., 383
Boylan C., 462
Brabbins D., 1022, 1028
Bracarda E., 588, 594
Bracco F., 863
Bracko M., 1068
Brada M., 475
Bradley D., 484
Bradley J., 452, 1512
Bradnam T., 852
Brakenhoff R., 89
Brambilla M., 926
Brambilla M. G., 437, 863
Brame S., 1298
Brammer C. V., 1300
Brandhof V., 1258
Bratengeier K., 416, 1355
Bratos K., 9
Brattheim B., 1415
Bravin A., 143, 1547
Brealey E., 650
Brearley E., 679
Brecelj E., 1068
Breedveld S., 318, 534, 1343
Brennan S., 841, 1148
Brenner C., 1425
Bresciani S., 954
Brettle D., 1295
Brgentin A., 953
BRIME R., 1244
Brink C., 326, 460, 912, 1176, 1181, 1273,
1292, 1316, 1481, 1483
Brittain M., 1416
Brock K., 280
Broderick M., 1337, 1503, 1537, 1566, 1589
Brodin P., 181, 908
Broggi G., 953, 960, 976
Broggi S., 98, 507, 753, 868, 878, 1049
Brooke S., 660
Brooks C., 1303
Brouwer C., 1282
Brown D., 1150
Brown E., 618
Brown M., 1578
Brualla Gonzalez L., 371
Brualla L., 1390
Brualla-González L., 423
Bruggmoser G., 1193, 1491
Bruheim K., 1057
Bruhn M. A., 515
Brunaud C., 554
Brunet G., 1127, 1129
Bruni A., 861, 1233, 1245, 1264
Brunner T., 1050, 1354
Brunt A. M., 735
Brustugun O. T., 1158
Bruun M. T., 515
Bruzzi M., 1423
Brás J., 1532
Brömme J. O., 823, 893, 902
BS A. K., 825
Bucciolini M., 1423
Buchwald C., 515
Budgell G., 1375
Budiharto T., 322
Budrukkar A., 293
Buechler M., 33
Buettner F., 447, 448
Bufacchi A., 1549
Buglione M., 907, 952
Buijsen J., 1208
Buikhuisen W., 276
Bujko K., 167, 1066
Buls N., 250
Bulsara M., 311, 614

Bulski W., 1094, 1455
Bundgaard T., 515
Bundschuh R., 1160
Bunkheila F., 811
Burchardt W., 626, 724
Burgers S., 276
Burke K., 475, 1026, 1027, 1260, 1270
Burmeister B., 1579
Burneckis A., 720, 819, 1017
Burnet N., 940
Burnley J., 1460
Burris-Mog T., 563
Bush M., 690
Busk M., 808
Busnardo E., 868
Bussink J., 132, 205, 286
Bussu F., 847
Bustos J. C., 12
But Hadzic J., 715
Butt S., 687
Butterworth K., 263, 453
Butti I., 1372
Bydder S., 1143
Byrne P., 936
Byrski E., 1339
Bystrzycka J., 725
Bzdusek K., 238, 1283
Bäck S., 1098, 1210, 1255, 1559
Béliveau-Nadeau D., 83
Bø B., 1083
Børresen-Dale A. L., 235
Cabañas L., 14
Cabello Murillo E., 608, 1107, 1436, 1442
Caffo O., 716, 749, 1040
Cagna E., 177
Cagney C., 841
Cagney D., 841
Cagni E., 408, 891, 1161, 1494
Caivano R., 663, 1005, 1350
Cakina S., 756, 886
Calaguas M. J., 871
Calais G., 135
Calama Santiago J. A., 25
Calandrino R., 98, 500, 507, 753, 868, 878,
1049, 1312, 1332, 1517
Califano G., 663, 801, 1350
Call J., 17
Callister M., 13
Caloglu M., 916, 917
Calvo Crespo P., 1055
Calvo F., 12, 16, 19, 28, 29, 35, 38, 39, 585,
599
Calvo Ortega J. F., 1304
Calzada-Feliu S., 1392, 1486
Camacho C., 666, 1097
Camargo P., 526
Cambeiro M., 224, 289
Cambria R., 36, 1012
Camera L., 1139
Cammarano F., 835
Cammelli S., 675
Canales S., 965
Canals A., 1457
Canary P., 769
Candela F., 1487
Candiano G. C., 597
CANEVA S., 1317
Caneva S., 432
Cante D., 741, 1004
Cantisani P., 1003
Cantone M., 1128
Cao Y., 67
Capela M., 1465
Capezzali G., 889
Capp A., 637, 1202
Capparella R., 1549
Cappelletti P., 1409
Cappucci F., 437
caputo M., 1012
Caputo M. C., 294
Capuz B., 732
Carabelli G., 1262
Caravatta L., 1323
Carballo A., 1055
Carbonini C., 863
Carceller J. A., 747

Cardinali M., 1278
Cardoso D., 580
Cardoso I., 1531
Carey B., 936
Carita L., 1474
Carl J., 249
Carl R., 462
Carletti S., 1002
Carlone M., 1361, 1382
Carlos F., 29, 589, 591, 593, 603, 604
Carlsson Tedgren , 154
Carmona Meseguer V., 696, 733
Carmona V., 666, 1097
Carmone P., 1540
Carnell D., 1207, 1272
Carpentier I., 859
Carpino S., 27
Carrara M., 678, 727
Carrasco de Fez P., 361, 524, 1492
Carrascosa M., 290, 623
Carreira P., 1560
Carrier J. F., 154
Carriero M. A., 783
Carrizo M. V., 1008, 1413
Carroll D., 1425
Carruthers F., 582
Carty K., 828
Caruso C., 1353
Carvalho A. L., 1371
Carver A., 385
Casagrande W., 868
Casale M., 1002
Casals J., 1304
Casamassima F., 899, 1072, 1073
Casanova-Borca V., 741, 1004
Casarino C., 597
Casas F., 838
Casasnovas K., 178
Cascales M. A., 806
Cashmore J., 879, 1132, 1135, 1501
Casillas C., 589, 603
Castagna L., 415
Castaldo G., 663
Castelain B., 800
Castiglioni S., 415, 481, 870, 921, 1128
Castro Novais J., 1107
Castro Tejero P., 1106
Caterino M., 1139
Cathelineau X., 710
Cats A., 165
Cattaneo G., 753
Cattaneo G. M., 98, 507, 552, 878, 1312, 1332
Cattani F., 36, 722, 763, 807, 1012, 1063,
1163, 1243
Cattoni B., 1532
Catuzzo P., 741, 1004
Cavagnetto F., 24, 598, 898
Cavagnini R., 952
Cavalera E., 840, 867, 1041
Cavalli A., 762
Cavallini Francolini D., 835
Cavedon C., 174, 1095
Cavelaars F., 255
Caviedes Soto I., 920
Cavina R., 870
Cazoulat G., 176
Ceberg C., 1098, 1250, 1329
Ceberg S., 1098, 1210
Cebotaru C., 955
Cecconi A., 36, 722, 807, 811, 1063, 1163
Ceha H., 20
Cella L., 1139
Cellini F., 279
Cellini N., 294, 640, 869
Cemile C., 1443
Cenacchi E., 478, 861, 1233, 1245, 1264,
1519
Cernea V., 278
Ceroni P., 1233, 1245, 1264
Cerqua L., 1170
Cerqueira C., 580
Cerrotta A., 678, 727
Cerveira J., 1092
Ceylan C., 1306, 1348, 1524
Chai X., 531
Chakarova A., 754
Chakravarti A., 938

S 594

CHAMOIS J., 795
Chamois J., 1078
Champion H., 407
Chan O., 425
Chan S., 1326
Chan S. K., 430, 1429
Chandrasekaran M., 1147
Chang J., 1516
Chang J. Y., 233
Chang T. C., 883
Chang Y. C., 1301
Changizi V., 1563
Chantler H., 622
Chapellier C., 751
Chapet O., 170, 221
Chapet S., 135
Charnley N. G., 804
Charra-Brunaud C., 152
Chatry C., 1457
Chatterjee P., 613
Chatterjee S., 834, 843, 1469
Chau M., 1326
Chau M. C., 430, 1429
Chaudhari S., 1463
Chaudhri M. A., 1420
Chea M., 1127
Checcaglini F., 19, 588, 594
Chelminski K., 1094
Chen C., 100
Chen G., 175
Chen P., 229, 618
Chen Q., 1396
Chen W., 309
Chen X., 426
Chen Y., 1396
Cheng F. K. F., 1346
Chernykh M., 1048, 1081
Cherpak A., 525
Chesnut D., 632
Cheung K., 1326
Cheung K. Y., 430, 1429
Cheung M., 1326
Cheung M. L. M., 430, 1429
Cheung P., 1271
Chevrette E., 698, 705
Cheze Le Rest C., 1166
Chiara A., 753, 868
Chiari P., 1409
Chicata Sutmöller V., 760
Chicata V., 185, 652
Chichel A., 79, 626, 730
Chiesa S., 842, 845, 846, 997
Chiloiro G., 842, 997
Chin A., 132
Chin E., 465
Chitapanarux I., 53
Chiti A., 488, 572, 870
Chitra P. V., 160
Chiu G., 1346
Chiumento C., 801, 946, 1005, 1042, 1350
Cho B., 249, 463, 535, 1205
CHO Y. B., 655
Cho Y. B., 635
Choe B. Y., 833
Chofor N., 1125
Choi B. O., 881
Choi E. K., 789, 962
Cholewka A., 617, 662
Choong E. S., 650
Chopra S., 297, 634, 793, 1189
Choudhury A., 1308
Chow E., 520
Christensen A., 515
Christensen H. K., 296
Christianen M., 184, 1356
Christie D., 496
Chung C., 656
Chung E., 104
Chung H., 231, 1271
Chung M. J., 752, 1052
Chung S. M., 752, 1052
Chunta J., 1373
Chust M., 290
Ciabattoni A., 7, 19, 40, 312
Ciammella P., 408, 891, 1071, 1161
Ciccone V., 7
Ciccotelli A., 24, 27, 30, 596

AUTHOR INDEX
ciccotelli A., 26
Ciechowicz J., 1140
Cihoric N., 610
Cilla S., 869, 1323, 1461
Cima S., 675
Cirrone P., 1423
Ciuleanu T. E., 278
Ciurlionis L., 394, 395, 486, 1583
Civinini C., 1423
Claessen R., 1411
Clairand I., 1127, 1130
Clark B., 1451
Clark C., 363, 395, 486, 812, 1117, 1162,
1433, 1583
Clarke J., 639
Clarke M., 316
Claus F., 322
Clayton-Lea A., 1581
Clelland C., 826
Clemente Gutierrez F., 608, 1107, 1436, 1442
Clemente S., 801, 1042
Clerici E., 870, 921
Clivio A., 374, 400, 1438, 1480, 1544
Closset M., 1422
Cminal Mitjana J. M., 824
Cobbe A., 1582
Coccarelli F., 716, 1040
Coche E., 440
Coffey M., 341, 358, 566, 817, 1231, 1337,
1503, 1537, 1566, 1582, 1589
Coghetto F., 19
Colangione S. P., 763
Coles C., 394, 516, 622, 660, 1178
Colleoni P., 1131
Collette L., 207
Collette S., 207
Colley S., 873
Collins C., 1581
Collins I., 841
collins M., 936
Colmenares R., 732
Colombo A., 697
Colombo S., 835
Colomer M., 747
Comi S., 722, 1012, 1192, 1243
Comtat C., 1418
Conceicao L., 1555
Conceicao L. S. M., 1454
Conde-Moreno A. J., 1392
Conijn S., 275
Conson M., 1139
Consorti R., 7
Constantin D., 239
Constantinescu C., 665, 1079
Contavalli P., 1060
Contreras V. C., 623
Convery D., 1403
Coolens C., 443, 1293
Cooper R., 650
Coppes R., 368
Cora S., 900
Corbella F., 835
Coremans I., 964
Corica T., 614
Corn B., 327, 1253
Cornes D., 1579
Cornes P., 298
Corradini N., 737, 1307
Correa P., 1240
Corredoira E., 659
Corry J., 1579
Corsini L., 475
Cortes Giraldo M. A. C. G., 428Corvò R., 6, 19, 816, 898, 909
Cosar R., 756
Cosentino D., 948
Cosentino L. M., 40
Cosgrove V., 951, 1383, 1458
Cosset J. M., 198, 710
Costa A., 743, 1062, 1075
Costa Ferreira B., 315
Costelloe M., 653
Costi T., 478, 1179, 1233, 1245, 1264, 1450,
1519
Cotroneo E., 1170
Coulter J., 453
Courdi A., 751

Cousins A., 1300
Couteau E., 1120
Coutinho A. R., 1531
Coutts S., 950
Coveney F., 951, 1479
Cowan T., 563
Cowen M., 1265
Cowie E., 1584
Cox J. D., 233
Coza D., 664
Coza O., 495, 638, 664
Cozzarini C., 256, 396, 500, 1517
Cozzi L., 374, 400, 415, 870, 921, 1128, 1438,
1480, 1544
Cozzolino M., 1005, 1350
Craft J., 1512
Craig A., 817
Cranmer-Sargison G., 375, 1064, 1126
craus M., 869
Crawshaw J., 1162
Creak A., 497
Crean P., 1430, 1458
Crehange G., 178, 795, 1078
Crellin A. M., 679, 936
Cremers F., 317
Crespi M., 1440
Creutzberg C., 299, 556, 964
Crijns S., 139, 240
Crisci R., 768
Crispin V., 1247
Croce O., 1472
Cronin P., 1046
Crook J., 517, 680
Cruickshank C., 1299
Cruje C., 1361, 1382
Cruz M., 810, 839, 1021
Cserháti A., 1495, 1570, 1572
Cucchi M. C., 587
Cufflin R., 522
Cuijpers J., 50, 370, 1526
Cull A., 407
Cumming J., 516
Cunha A. J., 696
Cunningham J., 144
Currell F., 453
Cusco S., 1378
Cutanda Henríquez F., 1567
Cutarella D., 688
Cuthbert D., 1242
Cuttone G., 1423
Cygler J., 525, 1407
Cytron S., 1251
Cámara A., 1487
Córdoba A., 659
Córdova Bernhardt A., 920
D Abbiero N., 408, 891, 1071
D’ Agostino G. R., 842, 845, 846
D’ Amico G., 294
D’Abbiero N., 1161
D’Agostino G. R., 640, 997
D’Alonzo A., 6
D’Ambrosio C., 681
D’Amico R., 697
D’Amours M., 156
D’Andrea M., 24, 26, 27, 30, 596, 1115, 1116
D’Angelillo R. M., 279
D’Este C., 496
D’Onofrio G., 1461
D’Souza D., 1301, 1368
D’Souza W., 406, 1538
Dagnault A., 417
Dahele M., 1526, 1529
Daisne J. F., 854
Dal Moro F., 344, 1251
Dale R., 628
Daliot T., 1459
Damen E., 101, 253, 268, 391, 1556
Damen E. M. F., 217, 313
Dammene Y., 563
Dandamudi R., 821, 1036
Danhier S., 1248
Danielli C., 861
Darby S., 193, 1292
DAS K. J. M., 803
Datsenko P., 905
DATTA N., 1502

S 595

AUTHOR INDEXDavid I., 667
David S., 80, 302
Davidson N., 750, 767
Davies J., 244, 1152
Davies P., 1207, 1368
Davies S., 911
Davis S., 154
Davits R., 327, 1253
Dawson L., 520
Dayyat A., 820
Dazzini S., 1060
de Almeida C. E., 769
de Azevedo Gomes J. C., 1462
De Bast M., 440
De Blas Pinol R., 895, 1109
de Boer H., 1195
de Boer J., 1185
de Bois J., 100
De Brabandere M., 147, 219, 225, 792
de Bruin - Hordijk T., 510
De Chiara V., 875, 1275
De Cobelli F., 1049
De Cobelli O., 36, 722, 1012
De Deene Y., 1119
De Filippo L., 842, 845
De Gersem W., 188, 1190
de Goede M., 1362
de Haas-Kock D., 169
De Hertogh O., 137, 466
De Ieso P., 475, 668
De Jaeger K., 324
de Jager - Nowak H., 86
de Jong R., 109
De Kerf G., 1120
De Keyzer F., 332, 836
de Kruijf W., 327, 1253
De la Casa de Julian M. A., 608, 1107, 1436,
1442
de la Rosette J., 723
de la Vara Olivas V., 1008, 1389, 1413
de Langen M., 1108
De las Peñas-Cabrera M. D., 627, 629
de Leeuw A., 53, 147, 153, 299, 636, 796
De Liguoro M., 1352
De Marco G., 861
de Marco-Blancas N., 21, 1392, 1486
De Marzi L., 1418
De Neubourg F., 586, 601
De Neve W., 188, 837, 1190
De Nobili G., 1535, 1536
De Ost B., 1325
De Pascalis G., 802
de Reijke T., 264
De Ridder M., 69, 210, 250, 455
De Rosa N., 1139
De Rose F., 640, 846
De Ruysscher D., 68, 232, 268, 274, 304, 391,
471, 533, 1283
de Rycke Y., 307
De Santis M. C., 776
De Schutter H., 859
de Souza Lawrence L., 750
De Sá R., 1531
De Vecchi P., 835
De Villeres C., 1021
de Vries T., 86
De Wever L., 322
Deabreu A., 231, 1271
Dean J., 257
Deantoni C. L., 835
Deantonio L., 641, 926
Dearden R., 316
Dearnaley D., 1249, 1299, 1577
Dearnaley D. P., 334, 447, 448, 497, 517,
1338, 1573, 1575
Deasy J., 134, 452, 505, 506, 1512
Deasy J. O., 99, 397
DeBaere T., 203
Debelleix C., 135
Deberne M., 567
DeBlois F., 438, 740, 1242
Debouck F., 514
Debus J., 33, 164, 269, 600, 1196, 1568, 1580
Declich F., 697, 1372
Dees-Ribbers H. M., 476
Defraene G., 219, 319
Degli Esposti C., 587

Dejean C., 1379
Dekker A., 393, 1157
Del Moral F., 1088, 1100, 1365, 1367, 1462,
1482, 1493
Del Moral R., 631
Del Valle E., 38, 39
Delannes M., 152, 292, 333
Delgado Becerra I., 920
Delgado J. M., 12, 464
Deli A., 396, 753
Dell’ Acqua V., 722, 1163
Dell’Acqua V., 807
Dell’Oca I., 98, 753, 868
Della Monica P., 926
Delle Canne S., 177
Delouya G., 83
Deman P., 1576
Dempsey C., 637
den Hartogh M., 745
Denham J., 496, 1143, 1202
Denis J. M., 392
Denizli B., 916, 917
Dennehy M., 700
Deodato F., 869, 1323
Depuydt T., 69, 210, 250, 455
Derbyshire S., 1383
Derkman - van de Laak C., 1237
Derreumaux S., 1127, 1129, 1130
Dervenis C., 1061
Desbiens M., 156
Desco M., 28, 29, 599
Deshpande D., 160, 414, 634, 1463
deshpande D., 791
Deshpande S., 648, 1091
Dessena M., 5
Dessy F., 1422
Deutsch E., 567
Deutschmann H., 2, 312, 329, 331, 945, 1118,
1191
Devic S., 222, 740, 1242
Devilleres C., 810
Devlin B., 509
Deweese T., 141
DeWerd L., 1542
Dewitte A., 939
Dhawtal G., 1201
Di Gennaro D., 1535
Di Lorenzo R., 588
Di Muzio N., 98, 256, 868, 1517
di Muzio N., 552
Di Muzio N. G., 500, 753, 1049
Diamantidou E., 1059, 1061, 1067
Diamantopoulos S., 687
Dias A., 1169
Diaz-Zorita B., 38
Dickie C., 73
Dickson G., 453
Didier T., 514
Dieckmann K., 1504
Diez P., 84
Digesù C., 869, 1323
Dikken J., 165
Diletto B., 294, 640, 845, 846
Dilling T., 983, 1157
Dilworth J., 229
Dimakopoulou V., 855
Dimitrova N., 1069
Dimopoulos J. C. A., 148
Dina S., 785
Dinapoli N., 847
Dinesh Kumar ., 968
Ding C., 1520
Ding K., 517
Dingemans A. M., 274
Dinkla A., 704
Dionisi F., 863
DiPasquale S., 750
Dirkx M., 318
Dirscherl T., 451
Distefano G., 812
Dittmann F., 1289
Divan C., 716, 1040
Djordjevic M., 927
Dobler B., 1197
Dobrovolskaya N., 501
Doe S., 1416
Dogan N., 1335

Doi H., 914, 1096
Doino D., 898
Dok R., 850
Domingo C., 422, 1099, 1104, 1497, 1500
Domingo G., 686
Dominguez Dominguez M., 185, 652
Domínguez Folgueras A., 1488
Domínguez M. A., 760
Donadoni L., 907, 952
Donath D., 83
Donato V., 1353
Donegani E. M., 1409
Dong L., 233
Donini E., 408, 891, 1071, 1161
Donker M., 207
Donovan E., 1178
Doornaert P., 132
Dordai D., 1030
Dordai E., 1030
Doria D., 1425
Doro R., 899, 1072, 1073
Dorota K., 706
Dosanjh M., 269
Dosoretz D., 884
Doucet R., 1074
Dowdy S., 41
Downes P., 1220, 1473
Doyen J., 170
Drago S., 7
Dragovic A., 150
Driscoll B., 443, 1293
Driscoll C., 1029
Drouin P., 302
Drzewiecka B., 1360
Duane F., 645
Duane S., 49, 103, 376, 1117
Dubois L., 304
Duchateau M., 69
Duchesne G., 1143, 1579
Duker J., 922
Duma M. N., 844
Dumas I., 295, 649
Duncan G. G., 517
Dunn L., 1136, 1398
Dunne M., 645, 1581
Dunscombe P., 1150, 1376, 1451
Duppen J., 1145, 1281
Duprez F., 837
Durante M., 123
Duratti M., 1440
Durmus Altun G., 916
Dutreix A., 502
Dworzecka U., 1019
Dworzecki T., 1019
Dybvik K. I., 1216
Dymecki D., 167
Dymek P., 880
Dymnicka M., 734
Dziki A., 167
Díaz Díaz V., 627, 629
Díaz Fuentes R., 608, 1107
Díaz Gómez L., 627, 629
Díaz-Zorita B., 16
Dóczi T., 1523
Döring M., 688
Dörr W., 125, 338
D’Souza D., 1006
E. Nielsen J., 459
Eagle S., 1178, 1249
Eaton D., 1009
Ebert M., 1143, 1510
Ebinu J., 944
Eble M., 1
Eccles C., 1354
Eddy A., 114
Edgren M., 1513
Edhemovic I., 1068
Edouard M., 1576
Edvardsen H., 235
Edwards C., 1437
Eeles R., 497
Eenink M., 1349, 1362
Egestad H., 1408
Eggels-Emans D., 268
Egger J. F., 1045
Egmond, van J., 1506

S 596

Együd Z., 1572
Eichberger P., 1459
Eichner R., 300
Eidt S., 4, 11
Eito C., 185
Ekberg L., 1559
El Bakry H., 949
El Barbir H., 906
El Naqa I., 1512
El-Mesbahe-Bouzeya N., 996
El-Sayed M., 949
Elantholi Parameswaran S., 82, 680
Elezra D., 782
Elfering L., 328
Elkhuizen P., 458, 1277
Elleaume H., 1576
Ellegaard M. B., 330
Elliott C., 1031
Elnaggar M. H., 949
Elstrøm U. V., 1194
Elías S., 659
Emens L., 750, 767
Emmens D., 1548
Engel K., 317
Engelholm S. A., 398, 985, 1558
Enghardt W., 126, 563, 1421
Engin K., 1306, 1348, 1443, 1524
Engineer R., 297, 634, 791, 793, 1189
Eniu D., 664
Enmark M., 1250
Enwright K., 950
Erickson B., 175
Eriksson J., 304
Eriksson K., 252
Escude L., 965
Esfahani M., 1366, 1563
Eskiocak S., 917
Esmail A., 1015, 1430, 1479
esmail A., 1444
Espino J. M., 428
Espinoza I., 1511
Estornell Gualde M. A., 849, 995
Estève F., 1576
Etemadnia A., 1521
Ettore F., 751
Eudaldo T., 524, 1492
Evans P., 461, 1167, 1178, 1249, 1319
Evans W., 680
Eve A., 736, 1141
Evensen J. F., 136
Ewertz M., 1292
Expósito M. R., 102, 1099, 1104, 1498, 1499
Eyre K., 387, 622
Ezzat M., 665, 1079
Fa X., 1340
Fabretti F., 40
Fabrizio F., 594
Faggiano E., 48, 878
Fagim M., 785
Fahrig R., 239
Fairchild A., 182, 392
Fairfoul J., 257, 387
Faivre S., 135
Fakhr A., 949
Falcinelli L., 762, 768, 889
Falciola F., 478
Falco M. D., 875, 1115, 1116, 1275
Falk M., 463
Falkov A., 1344
Fallai C., 678, 727, 1262
Fallmyr I., 1410
Fallon A., 817
Fallone G., 306
Falzetti F., 1060
Fandiño Lareo J. M., 1106
Fanti P., 1012
Fanti S., 811
Farella A., 1139
Fariselli L., 953, 960, 976
Farkas R., 1523, 1551
Farneti A., 762, 768
Farrell T., 1284
Fasci E., 588
Fassi A., 532, 1218
Fast M., 241
Fastner G., 2, 3, 312

AUTHOR INDEX
Fauler A., 1165, 1171
Favretto M. S., 900
Fayad H., 247
Federico M., 151, 242, 646
Fehlauer F., 1471
Feigenberg S., 406, 775, 1538
Fekete Z., 955, 1030
Fekkes S., 695
Feldman J., 901
Felici G., 23, 24, 27, 30, 595, 596
felici G., 26
Fellin F., 256
Fellin G., 177, 396, 716, 1040
Fenton P., 182, 392
Fenwick J., 399
Fernandes A., 1532
Fernandez Sanmamed M., 224
Fernandez Leton P., 1239, 1342, 1448
Fernandez-Leton P., 1133, 1347, 1401, 1553
FERNÁNDEZ I., 1244
Fernández Bedoya V., 1244
Fernández Cerezo S., 1488
Fernández Fernández E., 1055
Fernández Lizarbe E., 14, 15, 676, 732
Ferrand R., 1418
Ferrando Sanchez A., 608, 1107
Ferrari A., 8
Ferrari M., 1276
Ferrari S., 675
Ferraro A., 675
Ferreira B. C., 1417
Ferreira P., 1532
Ferrer Albiach C., 21, 25, 1392
Ferro M., 1323
Fersht N., 827, 982, 1301
Fersino S., 294, 845
Fetting J., 750, 767
Feuillade J., 1379
Feygelman V., 983
Fiandra C., 1327
Ficarra V., 344
Fidanzio A., 1323, 1461
Fidarova E., 54, 646
Fiederle M., 1165, 1171
Fiedler F., 1421
Fiege J., 407
Fietkau R., 227
Figl A., 751
Figl M., 1215
Figueira A. R., 1371
Fijalkowski M., 662, 725
Fijałkowski M., 719
Filice S., 1494
Filipowski T., 706, 780, 882, 924
Fiore D., 906
Fiore M., 279
Fiorentino A., 783, 801, 946, 997, 1005, 1042
Fiorica F., 867
Fiorini F., 1425
Fiorino C., 98, 177, 256, 396, 500, 507, 753,
868, 878, 1049, 1144, 1312,
1332, 1517
Fischedick K., 1
Fitch T., 13
Fitzgerald T. J., 1298
Fitzpatrick M., 426
Fix M., 380, 1384
Fix M. K., 1391, 1399
Fledelius W., 249, 251, 459, 535
Flentje M., 95, 416, 1355
Flipo B., 751
Flitsch R., 1206
Floors-Stortelder C., 1237
Fluehs D., 1390
Flynn R., 159, 1533
Fodor A., 753, 868
Fodor C., 8, 36, 722, 807, 1012, 1063, 1163
Fodor E., 1570, 1572
Fodor J., 230, 874
Fog L., 1558
Fogliata A., 374, 400, 415, 481, 870, 921,
1128, 1438, 1480, 1544
Fokdal L., 296, 1077
Fokdal L. U., 53, 149, 301
Folkedal , 1083
Followill D., 392
Fontana G., 174

Fontanarosa D., 529
Fonte D., 743, 1062, 1075
Foo K., 1146
Footman M., 1403
Foppiano F., 681
Ford E., 141, 1515
Formenti S., 129
Forner A., 1374, 1546
Forster K., 758, 983, 1157
Forstner D., 113
Fortunato M., 1131
Fosså S. D., 235, 547
Foster R., 477, 1520
Foster W., 707
Foti C., 1440
Fotina I., 151, 261, 381
Foulsham A., 653
Fouraki S., 971
Fournier-Bidoz N., 761, 769
Fourquet A., 237, 307, 761, 769, 1317
Fowler J., 848
Fox G., 828
Fox S., 755
Fraenzle A., 1287
Fragkandrea-Nixon I., 990, 994
Franca S., 1400
Franceries X., 333
Francesca C., 594
Francesca F., 594
Franceschini G., 776
Franceschini M., 1262
Francisco S., 1088, 1462
Franco P., 741, 1004
Francois P., 432, 1317
Franich R., 1136, 1398
Franji I., 113
Franken E., 1506
Franken S., 1016, 1037, 1259
Franks K., 936, 1528
Fransson K., 1203
Frantzen-Steneker M., 1159
Franzetti Pellanda A., 737Franzini A., 953
François C., 307, 769
Fras A. P., 957
Frascino V., 845, 846, 997
Frassica D., 750, 767
Frassoni F., 909
Frata P., 739
Frauchiger D., 1399
Frederiksen B., 183
Fredriksson A., 254
Frei D., 380, 1384, 1391, 1399
Fresco L., 821
Frew J., 843
Frezza G., 587
Frigerio C., 697, 1372
Frigerio M., 1409
Frisson T., 1385
Fritel X., 656
Fromm L. S., 844
Frueh M., 893, 902
Frykholm G., 1149, 1415
Fröhlich G., 230, 615, 658, 692
Frøseth T. C., 1149
Fujiwara M., 914, 1096
Fukada J., 1023
Fuller C., 1145
Fung W. W. K., 187
Furlong R., 950
Furner R., 1416
Furuya T., 860
Fusco V., 663, 783, 801, 946, 1005, 1042,
1350
Fusconi F., 588
Fyles A., 635, 655
G.Loew H., 1164
Gaal S., 1570
Gabrys D., 118, 487, 772
Gach T., 167
Gackle M., 1451
Gademann G., 119
Gaetano P., 847
Gagliardi G., 363
Gagne N., 922
Gagnon J. C., 372

S 597

AUTHOR INDEX
Gago Arias A., 371
Gainey M., 416, 1355
Gains J., 958
Galas Swidurska D., 1236
Galeandro M., 408, 891, 1071, 1161
Galelli M., 1131
Galer S., 1112
Gallardo M. I., 428
Galli J., 847
Galuppi A., 675
Galuppo S., 900
Galvin J., 1298
Galyautdinova Z., 1518
Gambacorta M. A., 65, 842, 1060
Gambarini G., 678
Gambaro G., 291, 592, 641
Gandhi A., 674
Gandhi A. K., 805
Gangopadhyay A., 613
Ganswindt U., 992, 1001
Garant A., 1242
Garaud P., 135
Garavoglia M., 592
Garcia Alonso E., 747
Garcia I., 611
Garcia J. A., 464
Garcia M., 727
Garcia R., 524, 1188
Garcia Reglero V., 747
Garcia-Fuste M. J., 422, 1104, 1497, 1500
Garcia-Romero A., 25
Garcia-Sabrido J. L., 16, 35, 39
Garcia-Vicente F., 1244GARCÍA FIGUEIRAS R., 1055
García Gómez S., 1488
García Ruiz-Zorrilla J., 1107, 1133, 1239,
1342, 1347, 1401, 1448, 1553
Garelli S., 669, 681, 898
Garg M., 1251
Gargioni E., 317
Garibaldi C., 36, 362, 1012, 1243
Garipagaoglu M., 616, 1199
Garrett-Mayer E., 750
Garrett-Mayers E., 767
Garth M., 633
Gaspar J., 1454, 1555
Gaspar Martinez C., 849
Gauden R., 731
Gauden S., 731
Gauer T., 317
Gauthier M., 178
Gauthier P., 302
Gautier C., 307
Gautier M., 1379
Gavrilovic D., 1065
Gavris S., 664
Gawkowska-Suwinska M., 719, 725, 1019
Gaze M., 958, 982, 1301
Gaztañaga M., 224, 289
Geelen B., 1108, 1263
Geertsen P. F., 403, 419, 1258
Geets X., 440, 573, 1182
Geinitz H., 844
Gelosa S., 1409
Gelover Reyes E., 1427
Gendrin C., 1215
Geng H., 1318
Gentil Jiménez M. , 631
Gentilli S., 592
Georg D., 151, 218, 261, 381, 469, 1024,
1215, 1328, 1504
Georg P., 469
George L., 1501
George R., 557
Georgiou E., 1087
Geraedts W., 274
Geretschläger A., 823
Gerger A., 913
Gerig L., 828
Gernot E., 602, 1173
Geropantas K., 852, 858, 877, 894
Gershkevitsh E., 1557
Gershkevitsh M., 1557
Gesheva-Atanasova N., 885
Geukes L., 1184
Gevaert T., 69
Gez E., 1251

Gherardi F., 36, 722
Ghetti C., 1494
Ghilezan M., 229, 618, 712, 1020, 1022, 1028
Ghilezan N., 955
Ghosh K., 613
Ghosh-Laskar S., 133, 293
GHOSHAL S., 872
Giacobazzi P., 1264
Giampaolo R., 594
Giandini T., 1431, 1432
Gianfreda C. D., 1003
Giannelli F., 669
Giannini G., 1409
Gianoli C., 174
Gianolini S., 1162
Gianolli L., 868
Giantsoudi D., 402, 1145, 1449
Gibon D., 389
Gibson A., 1424
Gidding C., 1351
Giglok M., 719, 725, 1019
Gilardi M. C., 597
Gilhuijs K., 96, 309, 444, 745
Gill E., 1231
Gillespie D., 822
Gillham C., 53, 645
Gillis S., 1422
Gilmore J., 649
Gilmore M., 385
Gimeno J., 1247
Gingras L., 372, 386, 431
Giordano C., 596
Giorgi C., 1002
Gipson A., 620
Girelli G., 177, 741, 1004
Giri M. G., 1095
Giske K., 1196, 1288, 1289
Giunta A., 1071
Gizynska M., 1565
Gladilina I., 1048, 1081
Glegg M., 1322
Glessmer S., 1471
Glimelius B., 64
Glinski B., 880
Glowacki G., 772
Glück S., 2, 3
Gobbi G., 1370
Godart J., 427, 429
Godballe C., 515
Godwin G., 1561
Goetz P., 944, 979
Goitein G., 977
Goksel E., 616, 1199
Goldenberg L., 517
Goldner G., 469, 1024
Golling C., 738
Gomellini S., 1539
Gomez Caamaño A., 1055
Gomez D., 518
Gomez F., 371, 422, 423, 1099, 1104, 1113,
1497
Gomez-Espí M., 38, 39Gomez-Iturriaga A., 680
Gonzalez Calvo E., 627, 629, 671
Gonzalez Delgado F., 670
Gonzalez Imhof M. N., 670
Gonzalez Perez V., 1247
Gonzalez-Bayon L., 16, 35
González Soto X. L., 422, 1099, 1104, 1113
González-Castaño D. M., 371, 423
González-San Segundo C., 29
Goossens S., 1182
Gordon J., 258
Goset Poblete K., 920
Gospodarowicz M., 517
Gothard L., 911
Gottardi G., 1450
Goulet M., 386
Gounaris A., 757
Gouvas N., 1059, 1061
Goy Y., 317
Graas E., 1182
Grabec D., 1280
Grand M., 1579
Granger P., 1045
Granja C., 390
Granot H., 782

Granton P., 155, 809
Grantzau T., 125, 308
Grassi G., 7, 40
Grassi I., 811
Grau C., 91, 136, 515, 915, 1194
Graves E., 434, 1103
Gray D., 950
Graydon S., 405
Graziano V., 802, 971
Greco F., 1461
Green J., 1425
Green M., 1405
Green S., 1425
Greener A., 1403
Greer P., 1202, 1395, 1522
Gregory D., 660
Griffiths Y., 1345
Grignon D., 536
Grills I., 618
Grimaldi F., 1139
Grimaldi P., 1353
Groenendaal G., 66, 321
Gromova N., 1518
Gross B., 441
Grosu A. L., 1160, 1491
Grozdanovska B., 934
Grubbels C., 1256
Grusio M., 30
Grzadziel A., 1447
Grzbiela H., 798
Grégoire V., 90, 182, 392, 440, 582
Guariglia S., 1095
Guay J. P., 1044
Guazzoni G., 500
Guckenberger M., 95, 549, 1283
Guden M., 1306, 1348, 1443, 1524
Guedea F., 670, 824, 895
Guenzi M., 6, 598, 749
Guerrero T., 631
Guerrero Urbano T., 425, 1162
Guglani S., 557
Guibert M., 292
Guidi G., 277, 478, 861, 1179, 1233, 1245,
1264, 1450, 1519
Guido A., 811
Guillot M., 372, 431, 1114
Guinot J. L., 290, 623
Guirado D., 689
Guirado Llorente D., 1484
Gulati A., 862
Gullane P., 851
Gulliford S., 447, 448, 519, 1148
Gulyasar T., 756, 886
Gulyban A., 69, 182, 392
Gunderson L., 13
Gunjur A., 947
Gunn B., 1144
Gupta A., 968
Gupta T., 133, 293, 414
Guren M., 1057
Gusinu M., 598, 898, 1530
Gustafson G., 229, 1020, 1022
Gustafsson H., 1098
Gutierrez A., 424
Gutierrez Bayard L., 629, 671
Gutierrez M., 1389
Gutierrez-Diaz J., 12
Gutiérrez Miguélez C., 670, 824
Guttman T., 278
Guédon J. P., 1569
Guérif S., 135, 656
Guérin L., 1385
Gwiazdowska B., 1455
Gérard J. P., 170, 221, 1472
Gómez Barrado A., 1244
Gómez Lanz L., 16
Haack S., 445
Haas R., 996
Habl G., 33, 600
Hadaki M., 958
Haddock M., 17, 34, 41
Haertl P. M., 1197
Haffty B., 628
Haga A., 246, 1175, 1198, 1266, 1296, 1333
Hager E., 312
Hahn C., 520

S 598

Haidara Z. A., 428
Haider I., 605, 606, 765, 1070
Haie-Meder C., 53, 54, 152, 295, 544, 554,
567, 649, 800
Hall E., 497, 1575
Hall M., 1491
Halle C., 1489
Halvorsen A. R., 235
Hamada N., 777
Hameed S., 1070
Hamilton C., 1516
Hammad K., 1045
Hammer P., 277
Hammerfjell Hagen K., 1083
Han C., 931
Hanada T., 721, 1023
Handley J. C., 735, 1437
Handley M., 1232, 1414
Hangard G., 333, 1457
Hannouf M., 897
Hannoun-Levi J. M., 751
Hansen C., 1481
Hansen C. R., 1176
Hansen H. J., 201
Hansen H. S., 136
Hansen M. H., 1213
Hansen O., 326, 912, 1176
Hansen R., 213
Hansen R. H., 479, 1505
Hansen S., 460
Hansen V., 1187, 1313
Hansen V. N., 449, 1303
Hanssen S., 1408
Hanyu N., 883
Hao L., 1112
Hardcastle N., 1283
Hardemark B., 252, 254
Harder D., 1125, 1227
Hargrove R., 718
Haridass A., 903
Harima Y., 786
Harrington K., 61, 519, 1148
Harris E., 394, 758, 1178
Harris K., 679
Harris R., 537
Harris V., 1187, 1299
Harrison L., 1403
Hartgrink H., 165
Harting C., 1511
Hartley A., 873, 879
Hasan S., 1409
Hashem S., 820, 928
Hashiba M., 778
HASHIMOTO H., 1047
Hassouna A., 665, 797, 949, 1079
Hathout L., 80
Hatt M., 1166
Hatting U., 1507
Hatton J., 1202
Hatton M., 1290, 1528
Hauben E., 850
Hauer-Jensen M., 349
Haustermans K., 93, 124, 173, 225, 322, 327,
1253
Haviland J., 911
Havrankova M., 961
Hawkes D., 457, 1214
Hawkins M., 449, 1303, 1334
Haworth A., 1143, 1579
Hawrylewicz L., 1140
Hayek S., 1022
Hayman O., 643
Hayward J., 1284
Hazell I., 1316
Heaton R., 388
Hedetoft M., 1559
Hee-Joung K., 1446
Heemsbergen W., 100
Hegazy N., 151, 242, 646
Heid O., 993
Heigrujam M., 1224
Heijmen B., 211, 318, 534, 1201, 1343
Heikkonen J., 1562
Heindrichs U., 1
Heinemann F., 1491
Heinzerling J., 477, 1520
Helfre S., 1317

AUTHOR INDEX
Helland , 235, 1158
Helle P., 1238
Hellebust T. P., 284
Heller J., 993
Hellinga H., 510
Helmbrecht S., 1421
Hempel D., 882, 924
Heney N., 536
Henne K., 1491
Hennequin C., 78, 975
Henriksen B. M., 985
Henry A., 691
Henry P., 72
Henríquez Hernández L. A., 788
Hensley F., 23, 33, 600, 602
Hepp R., 1254
Herfarth K., 1568, 1580
Herman J., 243
Hermans J., 1256
Hermans R., 332, 836
Hermida Lopez M., 694, 1340
Hernandez N., 392
Hernanz de Lucas R., 14, 15, 28, 676, 732
Herranz R., 35, 38, 39
Herskind C., 10
hertens D., 586
Hervas Moron A., 14, 15, 676, 732
Hervieux Y., 83
Hetnal M., 880
Heuvel van der M., 100
Heuvelmans D., 1256
Heyes G., 1122, 1124, 1222
Hibbard L., 1291
Hica S., 638, 664
Hideghéty K., 1495, 1570, 1572
Higano C., 517
Hilgers G., 214
Hill E., 1050
Hill G., 540
hindley A., 804
Hindrichs N., 4, 11
Hinnen K., 1037
Hirakawa H., 856
Hirons J., 935
Hirota S., 914, 1096
Hirowatari H., 860
Hjelm-Hansen M., 1445
Hjelstuen M. H. B., 1216
Hlavin Bell E., 938
Ho Y., 956
Ho Y. W., 1318
Hoa P. L., 83
Hodgetts I., 731
Hodgson D., 1403
Hoejbjerre K., 251
Hoekstra C., 701
Hoevenaars S., 320
Hoff C., 131
Hoffe S., 983
Hoffmann L., 213, 377
Hofmann G., 910, 913
Hogg E., 684
Hogg M., 804
Hoisak J., 470
Hol S., 327, 1253
Holch Kristensen B., 403, 479
Hollander A., 853
Hollensen C., 1297
Holloway L., 113
Holloway L. C., 239, 1345
Hollywood D., 841
Holmberg M., 915
Holmberg O., 145
Holmes D., 764, 766
Holt A., 217, 313
Holt M. I., 172
Holt T., 520
Holy R., 1
Homayuni A., 1504
Hong C., 1204
Hong S. W., 833
Hong Z., 1520
Hoogeman M., 211, 1201
Hoogsteen I., 132
Hooton B., 1143
Hope A., 452
Hopfgartner J., 381

Hortobagyi E., 173
Horváth Z., 1523
Horwich A., 497
Horwitz E., 517
Hoskin P., 53, 54, 84, 225, 346, 520, 668
Hosono M., 1552
Hostalot C., 965
Houben R., 274
Hounsell A. R., 263, 453
Hourmouzi D., 1059, 1067
Houston R., 72
Houweling A., 260, 314, 829
Hoyer M., 172, 506, 915
Hrbacek J., 405, 467, 482
Hsu I. C., 696
Huang J., 1028
Huang S. H. (., 851
Huang Y., 632, 1533
Huber P., 33, 600, 1196
Huber S., 331, 945, 1118
Huddart R., 497, 548, 1187
Hudej R., 53, 630, 654, 957
Huerga C., 659
Huertas C., 659
Huet C., 1127, 1129, 1130
Hug E., 124, 411, 521, 977
Hugen D., 1263
Huges T., 993
Hughes S., 866
Huh H. D., 1359
Huilgol N., 1142
Huizenga H., 1411
Hulshof M., 328, 531
Humphrey P., 298
Humphreys M., 1260
Humphreys S., 657
Hunt D., 536
Hunter R., 1284
Hurkmans C., 182, 392, 564, 1277, 1298
Husband D., 1240
Huscher A., 739
Husnain G., 963
Hussein M., 425, 1433
Hutton D., 114
Hviid N., 1258, 1507
Hyland W., 453
Hynds S., 72
Hysing L. B., 262, 506, 1186
Hyödynmaa S., 439, 1417
Hörling M., 419
Højgaard L., 1297
Høyer M., 459, 485, 1285
Hüpf T., 1226
Iaccarino G., 24, 26, 27, 30, 596
Iacovelli N. A., 1049
Iafrate M., 344
Ibbott G., 1542
Ibis K., 916, 917
Ibraimova M., 1035
IGLESIAS J., 1055
Igor B., 436
Ihrai T., 751
Ikbal S., 1532
Ikeda S., 972
Ikink M., 214
Ilin M., 896
Illana C., 28
Imae T., 1175
Imboden A., 1578
Immerzeel J., 701
Immink M., 1263
Imtiaz S., 963
Inamura K., 1235
Indrieri P., 948
Infante Utrilla M. A., 25, 28
Infusino E., 481, 1128
Ingle C., 1554
Ingram W., 1249, 1314
Inomata S., 1235
Inoue H., 914, 1096
Inoue Y., 1025
Intven M., 446
Iordachita I., 141, 243
Iotti C., 19, 408, 499, 749, 891, 1071, 1161
Ippolito E., 279, 869
Iqbal S., 963

S 599

AUTHOR INDEX
Ireland R., 1290
Irimie A., 638, 664, 673
Iriondo U., 1374, 1546
Irish J., 851
Irvine D., 72
Isa N., 925
Isaak B., 610, 1391
Isacsson U., 1252, 1330, 1441
Isebaert S., 322
Ishii K., 1552
Ishimaru F., 1096
Islam M., 388
Istrate S. A., 673
Italiani M., 1002
Ito H., 1296
Itoh S., 1333
Itou Y., 1234
Iupati D., 1031
Ivaldi G. B., 8, 744
Ivanauskas A., 720, 1017
Ivashin A., 896
Iversen K., 1216
Iwai Y., 1333
Iwasaki K., 1369, 1467
Iwata T., 729
Izewska J., 512
Jaberi R., 1086
Jackson A., 244, 456
Jackson I., 770
Jackson M., 1579
Jacob K., 1532
Jacob V., 1160
Jacobs L., 750
Jacobson G., 441
Jacques R., 141
Jaffray D., 142, 388, 470, 480, 699, 1031, 1293
Jaganathan A., 1142
Jagtap V., 160, 634
Jahr M. H., 1213
Jain P., 399, 892, 1528
Jain S., 453, 805
Jakobsen A. R., 915
Jakobsen K. L., 1268
Jakse G., 1206
Jakubek J., 390
Jalali R., 414
Jamema S., 160, 293, 634, 791
James A., 1322
James H., 1015, 1444, 1554
Jameson M., 113
Jampana P. R., 930
Jamshed A., 1070
Jan S., 1418
Jang H. S., 881
Jang M. H., 1515
Jani Z., 1260
Jansen E., 165
Jansen W., 483
Janssen H., 53, 219, 792
Janssen M., 168, 474
Janssen T., 253, 413, 1277
Janssens G. O., 1351
Janulionis E., 651
Jaradat I., 820, 928
Jaradat I. J., 677
Jarvis R., 1220
Jena R., 394, 642, 940
Jennissen J., 4, 11Jensen C., 1410
Jensen H., 1273
Jensen H. K., 249
Jensen K., 136
Jeong S. M., 833
Jeong W. G., 833
Jeong Y., 962
Jereczek-Fossa B. A., 8, 36, 123, 125, 722,
763, 807, 1012, 1063, 1163
Jergas M., 4
Jespersen J. B., 515
Jeynes C., 1425
Jeynes J., 940
Jeynes J. C., 1588
Jezierska D., 978
Jezioranski J., 635, 655, 680
Ji Y. H., 833, 1093, 1446
Jiang L., 477

Jimenez E., 1008, 1413
Jiménez Spang F., 1427
Jocham D., 1251
Joep S., 526
Johannesen H., 1268, 1505
Johansen C., 85
Johansen J., 136, 515, 808
Johansson A., 379
John A., 1222
John M., 876
John W., 75
Johnson D., 951
Johnstone R., 657
Joiner M., 337
Jokelainen I., 1562
Jolicoeur M., 80, 302
Jones K., 1187
Jones W., 1145
Jong de M., 964
Joniau S., 322
Jonker H., 483
Jonker M., 483
Jonnada S., 653
Jorcano Picart S., 965
Jordan T., 425, 1162, 1433
Jornet N., 524, 1492
Joseph D., 311, 496, 614, 1143
Joshi S., 1204
Juan-Senabre X. J., 435, 1392, 1486
Julka P., 674, 799, 805
Jung D. K., 1032
Jung H., 1093, 1446
Jung J. Y., 833
Junge T. H., 515
Jurczykowski C., 780
Jussila A. L., 1154, 1587
Järvinen H., 357, 1562
Jürgenliemk-Schulz I. M., 53, 54, 147, 153,
299, 636, 796
Kaanders J., 132, 447, 1168, 1230, 1351
Kachnic L., 1145
Kacperek A., 966, 1424
Kacso G., 673, 955, 1030
Kadam S., 160, 414
kadam S., 791
Kader H., 77, 625
Kahlen A., 1505
Kahlke V., 220
Kahán Z., 1495
Kai K., 1369, 1467
Kainickal C., 814
Kairn T., 1136
Kakana C., 1059, 1067
Kakolee K., 1425
Kaldir M., 917
Kaljouw E., 723
Kallehauge J., 301
Kallur K., 825
Kalnicki S., 1251
Kalogera E., 757
Kaluza M., 563
Kam K., 1326
Kam M., 1318
Kamada T., 1053
Kamer S., 541
Kametriser G., 329
Kamikonya N., 914, 1096
Kamoi K., 729
Kamphuis M., 328
Kan T., 1025
Kanaev S., 759
Kaneda T., 721
Kanegae S., 1025
Kanehira C., 781, 1039
Kangas A., 1587
Kania M., 1455
Kanikowski M., 79, 626, 730
Kannan S., 133
Kannan V., 648
Kapp K., 910, 913, 1206, 1209, 1226
Kar S., 1425
Kara E., 1123, 1466
Karabis A., 402, 1084
Karagol H., 756
Karaiskos P., 1087
Karasawa K., 860, 883

Karczewska - Dzionk A., 9
Karger C. P., 1173, 1511, 1580
Kariya S., 713, 777
Karklelyte A., 774
Karlsdottir A., 506
Karlsson M., 379
Karsch L., 563
Kasper M., 733
Kato M., 1047
Katsilieri Z., 157, 687, 1084
Katsutake S., 1266
Kavanagh A., 1249
Kawabata Y., 972
KAWAGUCHI A., 972
Kawaguchi Y., 818, 918
Kawai D., 1234
Kazantsev P., 1397
Kazanzides P., 141, 243
Kazberuk D., 780
Kazi A., 1561
Kazmi A. S., 963, 1070
Kazmierska J., 282, 1236
Keall P., 239, 249, 463, 1205
Keall P. J., 251, 535
Kearvell R., 1143
Keditsu K., 648
Keen-Hun T., 496
Kefala V., 157, 687, 1084
Keiding S., 172
Keiichi N., 246, 1266
Kellas-Sleczka S., 617, 662, 725
Keller H., 443
Kelly C., 843
kelly C., 834
Ken S., 333
Kennedy L., 1503
Kenny J., 1581
Kerboua E., 864
Kerkar R., 793
Kerr C., 152
Kerr D., 491
Kerr H., 736, 1141, 1336
Kertzscher G., 384
Keshtgar M., 614
Kesteren van Z., 253, 1556
Kestin L., 1020, 1022, 1028
Ketelaars M., 147, 299
Khader J., 820, 928
Khalil A. A., 179
Khan A., 628
Khan S., 815
Khan Y., 779
Khanna N., 293
Kharma S., 677
Khaw M. T., 1344
Khaw P., 633
Khawandanah E., 186
Khmelevsky E., 501
Khoo V., 195, 305, 450, 475, 1011, 1026,
1027, 1187, 1232, 1257, 1260,
1270, 1414, 1516
Khorrami moghaddam A., 1102
Khouri C., 1078
Kida S., 246, 1175, 1198, 1266, 1333
Kierkels R., 325
Kiewiet de Jonge M., 86
Kilic A., 1306, 1348, 1443, 1524
Kilkenny M., 1207
Kim C. Y., 644
Kim J., 851
Kim J. H., 789, 962
Kim J. Y., 752, 1052
Kim K. B., 1093, 1446
Kim K. W., 1032
Kim M. S., 1093, 1446
Kim R., 150
Kim S., 787
Kim S. S., 962
Kim S. Y., 1402
Kim V., 1035
Kim Y., 159, 632
Kim Y. S., 789, 881, 962
King A., 853
Kingsley J., 523
Kinhikar R., 1463
Kinsella J., 841
Kippenes Skogmo H., 442

S 600

Kirby A., 394, 746, 1178
Kirby D., 1425
Kirisits C., 53, 54, 148, 151, 242, 285, 382,
554, 646, 693
Kirkby K., 940, 1112, 1425, 1588
Kirkby N., 940
Kirkels W., 711
Kirkland A., 1122
Kirova Y., 307, 761, 769, 1317
Kirrmann S., 1491
Kirwin S., 936
Kisielewicz K., 1339
Kitchener H., 555
Kjaer-Kristoffersen F., 1309, 1558
Kjærgaard B., 249
Klaeser B., 823, 893, 902
Klimanov V., 1397
Klinkó T., 1476
Klitgaard D., 1258
Klotz L., 517
Kluge T., 993
Klöck S., 405, 467
Knaup C., 404, 1082
Knegjens J., 275, 887
Kneschaurek P., 390, 1160
Knight M., 1585
Knopf A., 355, 383
Knöös T., 1250, 1329
Kobayashi K., 729, 778
Kobayashi M., 1039
Kobzda J., 607
Koch N., 1123, 1466
Koch S., 1237, 1238
Koch T., 977
Koch U., 126
Kodani N., 778
Koedooder K., 704
Koelbl O., 1197
Koenig T., 1165, 1171
Kofoed-Larsen E., 1083
Koizumi Y., 1234
Kok E., 1108
Kok J., 937
Kolarcik M., 693
Kolb F., 295
Koliouskas D., 990, 994
Kolkman-Deurloo I. K., 711
Kolodziejczyk M., 167
Komaki R., 233
Kon D., 1333
Kong P., 1318
Koning C., 723
Kononova G., 888
Konstanty E., 1404
Koper P., 20
Kopp M., 2, 3
Kopp P., 2
Kopsombut P., 1032
Korevaar E., 216, 427, 429
Korf A., 420, 1428, 1496, 1498
Korporaal J., 66, 321, 472
Korreman S., 463
Koshizuka S., 1296
Kosse J., 701
Kostovski A., 1267
Kostylev D., 1452
Kostylev V., 1453
Kotte A., 498, 1259
Kovacs P., 1523, 1551
Kovács G., 120, 220, 1251
Koziol I., 1251
Kozlov O., 1048, 1081
Koçak Z., 886, 916, 917
Kraft M., 1425
Kraft S., 563
Kragelj B., 715, 1280
Kragl G., 261
Kramer D., 214, 527
Krantz M., 1255
Kraus-Tiefenbacher U., 590
Krause D., 1078
Krause T., 823, 893, 902
Krauss A., 209, 454
Krauss D., 229, 712, 1020, 1022
Krautter U., 33
Krejci F., 390
Krempien R., 33, 600

AUTHOR INDEX
Krengli M., 19, 37, 291, 592, 641, 926
Kreppner S., 227
Kreth F. W., 970
Kretzschmar H., 981
Krishnamurthy D., 696
Kristensen B. H., 419
Kristensen C. A., 515, 1309, 1321
Kristensen G. B., 323
Kristensen V., 235
Krivokapic Z., 1065
Krivorotko P., 759
Krnic T., 1014
Krogh S. L., 1481, 1483
Kron T., 1136, 1398, 1579
Kropivnik M., 1068
Kruis M., 1159
Krupnov A., 1518
Kruszyna M., 1380, 1404
Kry S., 584
Kryński J., 1066
Ksiadz˛ B., 1094
Kubaszewska M., 607
Kubota K., 777
Kucucuk H., 616, 1199
Kucuk N., 1306, 1348, 1443, 1524
Kuechler S., 1193
Kufeld M., 1001
Kuga G., 883
Kui K., 542
Kuijpers A., 482
Kuipers J., 1506
Kuipers R., 723
Kukolowicz P., 1565
Kulik R., 118, 487, 772
Kumar M., 647
Kumar R., 799, 814, 1091
Kumar S., 791, 799, 803, 1345
Kumazaki Y., 781
Kunath D., 126
Kuncic Z., 1395
Kundapur V., 1064
Kunio O., 1467
Kunishima N., 883
Kunnambath R., 814
Kunze-Busch M., 1351
Kuo R., 1373
Kupelian P., 1230
Kuroda S., 1369, 1467
Kuroki Y., 769
Kurteva G., 1069
Kusnierz J., 167
Kusters M., 1351, 1411
Kuten A., 19
Kuzmanovic Z., 1267
Kuzmickiene I., 612, 624, 774
Kuzmina N., 1518
Kyed Jørgensen M. B., 213, 377
Kásler M., 230, 658, 874
K˛edzierski G., 1094
La Macchia M., 396, 675
La Porta M. R., 741, 1004
La Rosa V., 1424
Lachaine M., 243
Lacombe D., 182
Lacornerie T., 1130
Lacroix F., 1114
Lacroix V., 440
Lafay F., 1294
Lagares J. I., 102, 420, 422, 1099, 1428,
1497–1499
Lagendijk J., 121, 139, 240, 937
Lagerwaard F., 202
Lahooti A., 1101
Laing R., 425
Lakeman A., 268
Lala M., 648
Lallena A. M., 435, 1484
Lalondrelle S., 1187, 1311
Lam T., 1318
Laman M., 147, 299
Lamb C., 475, 672, 1011, 1026, 1027, 1257,
1270
Lamb D., 496, 1143
Lamb G., 1322
Lambert C., 1074
Lambertsen K., 515

Lambin P., 68, 168, 232, 274, 304, 393, 412,
471, 474
Lambrecht A., 1090
Lambrecht M., 173, 332, 836
Lamers E., 1556
Lammering G., 63, 168, 1208
Lancellotta V., 762
Landau D., 399, 1528
Landgren H., 1507
Landmark-Hoyvik H., 235
Landoni C., 868
Landoni V., 1539
Landry G., 81, 108, 155, 300
Lanfranchi B., 861, 1233, 1245, 1264
Lang P., 992
Lang S., 255, 405, 467, 482, 1578
Langan B., 645
Lange J., 750, 767
Langen K., 1230
Langendijk H., 124, 132, 184, 325, 410, 411,
1356
Langsenlehner T., 910, 913
Langsenlehner U., 910, 913
Lankester K., 1416
Lansiaux A., 939
Lanzoni L., 587
Laperriere N., 944
Laperriere N. J., 979
Laprie A., 333, 1457
Lapuz C., 637
Lara Jimenez P. C., 788
Lardies M. D., 599
Lardiés Fleta D., 25
Larouche R. X., 83
Larsen D., 1076
Larsen L. P. S., 459
Larsen R., 1297
larsimont D., 586
Lartigau E., 128, 939
Laschinsky L., 563
Lassen P., 131
Laterza G., 1540
Latifi K., 758, 983, 1157
Latorre Musoll A., 1492
Laurendeau D., 728
Lavado Rodriguez E., 25
Lavallée M. C., 705
Lavielle D., 1457
Lavigne B., 656
Lavoie C., 417
Lavrova M., 1557
Law N., 231
Lawford C., 1219
Lawrence R., 76
Lawton C., 536
Lazaro-Ponthus D., 1385
Lazarov R., 885, 1069
Lazzari B., 739, 952
Lazzari G., 1540
Lazzari R., 8, 36, 722, 807, 1063, 1163
Le Maitre A., 1166
Le Pechoux C., 192
Le Tinier F., 939
Leblanc-Onfroy M., 800
Leblond P., 939
Lee A., 991
Lee C., 158
Lee C. I., 833
Lee Dann C., 1076
Lee G. W., 752, 1052
Lee H. H., 1093, 1446
Lee I. G., 1052
Lee J., 158, 287
Lee J. A., 440, 474, 582
Lee J. H., 752, 1052
Lee K., 1326
Lee K. Y., 430, 1429
Lee R., 162
Lee S. W., 789, 962
Lee Y., 74, 1303, 1314, 1320, 1434
Leech M., 1231, 1589
Lei M., 1162
Leinders S., 534
Leite C., 1083
Leleu C., 1248
Lemanski C., 312
Lencart J., 1169

S 601

AUTHOR INDEX
Lennerts E., 854
Leogrande M. P., 889, 1370
Leonard J., 853
Leonard K., 922
Leonardi C., 749
Leonardi M. C., 8, 763, 1063, 1243
Leone A., 840, 867, 1041
Lepage M., 1098
Leppa A., 763
Lerouge D., 800
Lerut E., 322
Lestand L., 1418
Lesven C., 432, 1317
Letouze E., 170
Lettmaier S., 227
Leva L., 926
Levanat S., 770
Levegrun S., 1254
Levendag P., 211
Levernes S., 115
Levitchi M., 152
Lewandowska A., 978Lewandowski P., 1094
Lewis C., 1006
Lewis D. G., 522
Leysen K., 69
Leßmann E., 563
Lhommel R., 582
Lhommé C., 567
Li A., 175
Li F., 1269
li F., 1177
Li H., 477
Li J., 1174, 1177, 1269, 1406
Li S., 1028
Liao Z., 233
Liberini S., 878
Licher J., 1123, 1466
Licitra L., 59
Lidzey D., 523
Liebert W., 978
Liebich J., 1123, 1466
Liegard-Gauthier M., 795
Lievens Y., 574
Ligey A., 795, 1078
Liljamo P., 1154
Lilley J., 936, 1383
Lim Joon D., 450, 1232, 1414, 1516
Limbacher A., 618
Limbrick D., 853
Lin Z., 1341
Lind B., 1417, 1513
Lind S., 1258, 1507
Lindegaard J. C., 53, 54, 149, 296, 301, 384,
554, 1077
Lindsay P., 452
Lindsay R., 936
Linero D., 965
Liney G., 690
Linsenmeier C., 482
Linthout N., 1422
liotta M., 744
Lips I., 498
Lisbona A., 466
Lisi R., 971
Litiere S., 207
Litoborski M., 1380, 1404, 1478
Littler J., 892
Liu F., 175, 832
Liu F. F., 851
Liu P., 373
Liu P. Z. Y., 107
Liu Q., 10
Liu T., 1177
Liuzzi R., 1139
Lizuain M. C., 1109
Ljungqvist R., 1210, 1255
Lliso F., 666, 696, 733, 1097
Lloret M., 788
Lo Bosco A., 1115, 1116
lo presti D., 1423
Lo T., 672, 1046
Loadsman K., 1416
Lobefalo F., 415, 481, 1128
Loblaw A., 231, 1271
Locatelli F., 1527
Locke I., 746

Locquet J. P., 1120
Lodron G., 1206
Loe , 1213
Loeschel R., 1197
Loessl K., 610
Loft A., 473, 985
Logadottir A., 1241, 1309, 1321
Loi G., 37, 291, 926
Lolli G., 588
Lomax A., 354, 411, 521
Lomax T., 383
Lombardo E., 675
Londres B., 670
Longobardi B., 552
Loo S., 852, 858, 877, 894
Looe H. K., 1227
Lopes M. D. C., 146, 315, 579, 1454, 1465,
1555
Lopez Medina A., 1088, 1100, 1365, 1462
Lopez Tarjuelo J., 25
Lopez-Munoz M., 849, 995
Lopez-Tarjuelo J., 21, 1392, 1486
Lorentini S., 256
Lorenzen E. L., 1292
Loreti F., 1002
Loria D., 1561
Losio C., 1049
Losolla L., 228
Lotter M., 227
Lotterie J. A., 333
Loubser M., 420, 1428, 1496, 1498
Louie A., 897
Louwe R., 1230, 1351, 1411
Lovie S., 166
Lowe G., 53, 84, 283, 668
Lozano M. A., 35, 39
Lozares S., 652, 1374, 1546
LOZOYA R., 591, 593, 603, 604
Lu B., 1032
Lu W., 1396
Luca C., 1352
Luetolf U. M., 467
Lukas P., 1459
Lukka H., 536
Luna Vega V., 1055
Lunde R., 274
Lupattelli M., 889, 1060, 1378
Luppi E., 478
Lupton S., 735
Luraschi R., 1012, 1243
Lutgens L., 147, 1256
Lutterbach J., 1328
Lutters G., 815
Lutz S., 520
Luzi S., 294, 640
Luís A. L., 1532
Lwu S., 944, 979
Lyhne N. M., 515
Lynch R., 1294
Lyng H., 323
Lynn R., 989
Lyons C., 645
López J., 593, 603
Lövey J., 230
M J G., 825
Ma C. M. C., 1406
Ma F., 950
Maamoun J., 984
Maas M., 1159
Maas S., 933
Maass T., 1471
Macbeth F. R., 557
Macchia G., 869, 1323
Machado C., 580
Machitori Y., 883
Mackie T., 1396
MacKinnon M., 988
Maclean J., 1272
Macmillan C., 1489
MacPherson M., 1324, 1361, 1382
MacRae R., 525
Madani I., 188, 837, 1190
Maddalo M., 739, 907, 952
Madureira L., 1532, 1560
Magee D., 1295
Maggi S., 1278

Maggio A., 954, 1517
Maggiulli E., 98, 396, 507, 878, 1049
Magi S., 22, 595
Magli A., 1440
Magnani C., 641
Magrini S., 277, 739, 907, 952
Mahajan M. K., 876
Mahantshetty U., 54, 160, 297, 634, 791, 793
mahata A., 1469
Mahdavi S. R. M., 1388
Maheshwari A., 793
Mahon M., 1537
Mainardi H. S., 437
Maingon P., 178, 795, 1078
Maini F., 794
Majeed U., 605, 1070
Majewski T., 978
Majewski W., 1140
Major P., 536
Major T., 230, 615, 692, 874
Makris N., 1513
Maldonado J., 1340
Malecki K., 880
Mali W., 745
Malicki J., 1571
Malik Z., 399
Malinen E., 323, 442, 1158, 1514
Malinverni G., 499
Malisan M. R., 1440
Mallick I., 1469
mallick I., 834
Mallik S., 1224
Malone S., 517
Malthaner M., 893, 902
Maluta S., 19, 1095
Malveiro R., 1357
Mancini M., 344
Mancini S., 40
Mancosu P., 415, 481, 870, 921, 1128
Mandeville H., 1301
Maneru F., 1374, 1546
Manfrida S., 842, 845, 846, 997
Mangel L., 1523
Mangel L. C., 1551
Mangiacotti F. P., 7
Mangili P., 753, 1517
Mangiola A., 845
Manolopoulos S., 1122, 1124, 1222
Mans A., 215, 1377
Manser P., 1384, 1391, 1399
Mansur D., 853
Mantello G., 1278
Mantero E., 898
Manterola A., 185, 760
Mantini G., 776, 845–847
Marafioti L., 948
Maraldo M., 181, 908, 1292
Maranzano E., 1002
Maravi E., 185
Marcantonini M., 1370
Marcelino G., 702, 1092
Marcenaro M., 816, 898
Marchand V., 710
Marchant T., 244, 456, 1228
Marchesi V., 1212
Marchetti M., 953, 960, 976
Marchioro G., 37
Marciai N., 1095
Marcié S., 1379, 1472
Marcos F., 38
Mardynsky J., 1453
Margaritelli M., 762
Marguet M., 1188
Maria S., 1120
Maric P., 770
Maric T., 1568
Marijnen C., 92, 169, 483, 964
Marin-Muñoz J., 1113
Marina A., 594
Marinelli A., 20
Marini V., 1060
Marino D., 906
Marinova I., 754, 773
Mark R., 76, 85, 228, 611, 620, 621, 717, 718,
904, 942, 943, 956
Marples B., 1373
Marques de Jesus C., 702

S 602Marrazzo L., 277, 1423
Marsden J., 690
Marsh D., 1272
Marshall H., 1290
Marshall-Searson D., 950
Marsiglia H., 12, 19, 585
Martignano A., 1400
Martin A. G., 705, 707
Martin C., 852, 858, 877, 894
Martin de Vidales C., 1244
Martin E., 178, 1078
Martin G., 875, 1275
Martin J., 457, 1214
Martin-Albina M. L., 1374, 1546
Martinez A., 229, 618, 712, 1020, 1022, 1028,
1373
Martinez Carrillo M., 631
Martinez E., 824
Martinez Perez E., 670
Martinotti A., 1525, 1527, 1534
Martins A., 580
Martos A., 1008, 1413
Martín De Miguel M., 1436, 1442
Martínez Rodríguez D., 1487
Martínez-Monge R., 224, 289
Martínez-Rovira I., 1547, 1576
Maráz A., 1572
Masahiro H., 923
Masahiro M., 972
Masahito K., 1018, 1038, 1039
Masarykova A., 961
Mascaro F., 670
Masciullo S., 899, 1072, 1073
Masetti R., 776
Masi L., 899, 1072, 1073
Masini L., 291, 592, 641
Mason J., 691
Masood U., 606
Massabeau C., 761, 769
Massaccesi M., 869, 1323
Massaro P., 835
Massetti M., 889, 1034
Massey P., 1222
Massimiliano P., 594
Massimo A., 594
Massoptier L., 389
Mast M., 86, 510, 1506
Master Z., 133, 1189
Masutani Y., 246, 1175
Mataga V., 1014
Mateev V., 754
Matheoud R., 926
Matos Dias J., 315
Matrone F., 1034
Matsuda K., 1369, 1467
Matsumoto K., 1364
Matsuo M., 1025
Mattera A., 1409
Matthews J., 496
Mattiucci G. C., 776, 997
Matyakin G., 1453
Matzen T., 1441
Matzinger O., 182
Maucione A., 727
Mauguen A., 192
Mauri P., 1409
Maurizi Enrici R., 19
Maurizi F., 499
Mauro F., 499
Mauro R., 1063
mauro R., 1012
Mavroeidi P., 1121
Mavroidis P., 157, 402, 404, 426, 1082, 1084,
1145, 1417, 1449, 1513
Mawlong A., 634
maxwell R., 843
Mayer H., 1206
Mayles H., 1240, 1405, 1577
Mayles P., 385, 399, 550, 1577
Maylin C., 78, 975
Mazal A., 432, 769, 1317
Mazeron R., 53, 295, 649
Mazzeo E., 861, 1233, 1245, 1264
Mazzoleni F., 36
Mañas A., 659
Mc Andrew N., 736, 1336
Mc Garry C., 263

AUTHOR INDEXMcAleer J., 72
McAndrew N., 1141
McArdle O., 53, 645, 1581
McCaffrey J., 1009
McClelland J., 457, 1214
McCloskey P., 866
McConkey C., 873
McCurdy B., 407, 1395
McDonald F., 1187
McEwen M., 106, 1114
McGOWAN S., 1490
McGowan T. S., 1324
McGuire S., 441
McJury M., 1217
McKay M., 755
McKenna P., 1425
McKenna W., 1354
Mckenna W., 1050
McKenzie D., 107, 373, 1510
McMahon S., 453
McNair H., 51, 475, 1249, 1260, 1577
McNee S., 1217
meaglia I., 744
Meattini I., 277
Medal D., 1100, 1462, 1482
Medal Francesch D., 1088
Medford B., 1585
Medin J., 1441
Medoro S., 675
Meduri B., 861, 1233, 1245, 1264
Meehan C., 1315
Meertens H., 1282
Meghzifene A., 512
Mehyar M., 677
Meignan S., 939
Meigooni A., 1542
Meijer G., 324
Meilan E., 1365, 1367, 1462, 1482, 1493
Meilán Bermejo E., 1088
Meireles P., 743, 1062, 1075
Meirino R. M., 28, 29
Meirovitz A., 901
Meissner W., 167
Meister A., 815
Melchert C., 1251
Melchor M., 1487
Meldolesi E., 393
Melhus C., 1080
Meliadò G., 1095
Melich-Cerveira J., 702
Mellemkjær L., 308
Melnik Y., 905
Menard C., 470, 699, 944, 979, 1031
Mencarelli A., 1183
Menda Y., 441
Mendes R., 1207, 1272, 1368
Mendez Romero A., 534, 1343
Mendonça V., 702
Meng Y., 1512
Menichelli C., 899, 1072, 1073
Menk F., 1395
Mens J. W., 1201
Menten J., 859
Menzel C., 2, 3, 312
Merchant M., 940, 1425
Mercuri M., 675
Meregalli S., 790
Merlano M., 816
Merz F., 2, 312
Messa C., 597
Messai T., 649
MESSAOUD A., 1043
Metzkes J., 563
Meyer J. E., 120
Mhatre R., 1091
Mhatre V., 1224
Miah A., 519, 1148
Micciche F., 847, 997
Miccichè F., 846
Micera R., 891
Micev M., 1065
Michalecki L., 772
Michalski J., 853, 1298
Michaud S., 975
Michel R., 333
Mickevicius R., 819
Miechi R. J., 794

Mignano J., 922
Miguel C., 580
Mihailidis D., 426
Mihaylova I., 885, 1069
Mijnheer B., 215, 504, 526, 1377
Mikel R., 760
Miki K., 1018, 1038, 1039
Miki T., 729
Miki Y., 1552
Mikolajczyk K., 1435
Milakovic M., 1267
Milan Armengol A. P., 28
Milanesi I., 953, 960, 976
Milecki P., 9, 1010
Mileo A. M., 801, 946, 1005, 1350
Miles E., 395, 486, 1577, 1583
Milickovic N., 157, 687, 1084
Milletti A., 1378
Millin A., 522
Milosevic M., 635, 655
Minambres A., 1133, 1239, 1342, 1347, 1401,
1448, 1553
Mineo T. C., 279
Minguez C., 464
Mini R., 1391
Minkema D., 996, 1261
Minken A., 214, 527
Miquelez S., 1374, 1546
Mira Flores M., 747
Miralbell R., 965, 1045
Miranda S., 733
Miranti A., 954
Mirimanoff R. O., 737
Mirjolet C., 178
Mirri M. A., 7, 40
Mirzaii M., 1388
Misson-Yates S., 684, 1403
Mistretta G., 1179
Miszczyk L., 719, 1140
Misztal L., 772, 1140
Mitch M., 1542
Mitchell C., 75, 618
Mitra A., 1311
Mitreski N., 934
Mitrou E., 438
Mitsui N., 883
Mitterlechner B., 331, 945
Miura H., 914, 974
Miyagi K., 818
Mjaaland I., 1216
Mocan C., 1030
Moennich D., 1168
Moerland M., 121, 1016
Mohamed S. M. I., 149
Mohamed Yoosuf A. B., 683
Mohammed I., 928
Mohammed N., 1528
Mohan R., 233
Mohd Noor N., 484
Moinuddin S. A., 1207, 1272, 1301, 1368
Mojica R., 942
Mola D., 1540
Moldovan G., 1122
Molineu A., 392
Molls M., 844
Molnár G., 1570
Moman M., 66, 472, 1016
Momm F., 1491
Momma T., 1023
Monaghan A., 1589
Mondini L., 681
Mones E., 37, 592
Monfà Binefa C., 747
Mongioj V., 1262, 1431, 1432
Monica S., 525
Monninkhof E., 82, 745, 1037
Monroy Anton J. L., 849, 995
Monsalves E., 944
Montani E., 739
Montazeri A., 1029, 1058
Monteiro Grillo I., 1092, 1560
Monteiro-Grillo I., 702
Montero A., 14, 15, 676, 732
Montesdeoca N., 289
Montesi G., 1034
Montesi M. A., 802
Montgomery L., 828

S 603

AUTHOR INDEX
Monti A. F., 1409
Moody M., 516
Moonen L., 88
Moore C., 244, 456, 1228, 1286
Moore D., 628
Mooslechner M., 331, 945, 1118
Mora G., 1357
MORA M., 1244
Moragues S., 1304
Moran M., 866
Morbee L., 837
Morell Quadreny L., 849
Moreno Amagro S., 670
Moreno-Jimenez M., 289
Morera López R., 14, 15, 676, 732
Moretti E., 1440
Moretti L., 1032
Moretti R., 1131
Moretto D., 587
Morf D., 535
Morgan R., 425
Morganti A. G., 869, 1323
Morgia M., 635, 655
Moriarty M., 1581
Morice P., 567
Morillas Pérez M. D., 1488
Morillo V., 28, 589, 591, 593, 603, 604
Morillo-Macías V., 21
Morin F., 417
Morini L., 1450
Morley S., 1272
Moro G., 499
Morra A., 8, 1243
Morre Pedersen E., 445
Morrier J., 726
Morrone P., 875, 1275
Morselli L., 763
Mortensen H. R., 136
Mortensen L. S., 808
Morton G., 231, 1271
Mosalaei H., 1006
Mosconi F., 587
Moseley H., 1475
Mosely M., 1274
Moser E., 1248
Moser T., 1580
Mota M., 1560
Mott J., 843
Moule S., 950
Moura F., 581
Mourtada F., 58, 154
Moutsatsos A., 1087
Moyal-Cohen-Jonathan E., 333
Muacevic A., 1001
Muanza T., 740
Mucha-Malecka A., 880
Mui A., 1346
Muijs C., 325, 551
Muir B., 106
Muir M., 453
Muirhead R., 1217
Mukesh M., 516
Mukherjee S., 1489
Mula-Hussain L. Y., 820
Mula-Hussain L. Y. I., 677, 928
Mullaney L., 566
Mullassery V. M., 84, 668
Mulligan M., 1006
Mulè A., 776
Munck af Rosenschöld P., 181, 398, 463, 908
Munive Alvarez E., 627, 629, 671
Munoz F., 1327
Munoz Garzon V. M., 1088
Munshi A., 1137
Muraglia A., 408, 1161
Murawa D., 9
Muren L. P., 99, 172, 213, 262, 330, 363, 445,
485, 506, 915, 1186, 1194, 1285
Muresan M., 638
Murillo T., 608
Murphy J., 1324
Murray J., 1143
Murrer L., 300, 1485
Murthy V., 293
Muruzabal J. C., 652
Muscat S., 643
Musi G., 36, 722

Music M., 1068
Musio D., 802
Mussari S., 716, 749, 1040
Musunuru H. B., 1007
Mutaf Y., 406, 1538
Mutic S., 1298
Muñiz J., 102, 1099, 1499
Muñiz J. L., 420
Muñoz M., 39
Muñoz V., 1100, 1367, 1462
Myers L., 750, 767
Myint W., 1029
Mzenda B., 736, 1141, 1336
Méndez R., 1099
Müller J., 1578
Naeem M., 657
Naga A., 1079
Nagano H., 1047
Nageeti T., 779
Nagy V., 495, 638
Nahum A. E., 97, 180, 399, 1147
Nair M., 85, 228, 611, 620, 621, 717, 718, 942,
943, 956
Naismith O., 395, 1573, 1575, 1577
Najafi Y., 467
Najmudin Z., 1425
Nakagawa H., 1096
Nakagawa K., 1175, 1198, 1296, 1333
NAKAMURA S., 918
Nakamura S., 818
Nakamura T., 914
Nalder C., 1311
Nambi Raj A., 1138
Nanni C., 811
Napier S., 866
Narayan K., 633
Narayanan G., 1381
Narayanan S., 1381
Nardiello B., 1549
Nardone L., 776
Naredi P., 492
Naseem H., 1079
Natali M. G., 840, 867, 1041
Natarajan K., 935, 1574
Natarajan T., 1363
Natte R., 964
Naudy S., 178
Naumburger D., 563
Naumov D., 1048, 1081
Nava S., 499
Navarria P., 415, 481, 870, 921, 1128
Navarro Bergadá A. V., 849, 995
Navarro González M., 631
Navarro Jimenez D., 1109
Navarro V., 895
Navarro-Martin A., 895
Nawaiseh I., 677
Nawrocki G., 167
Ndlovu N., 784
Nechushkin M., 1048, 1081
Nedaei H. A., 1101
Nedaie H. A., 932, 1111, 1366, 1393
Needham A., 936
Neely D., 1425
NEGI P., 1502
Neglia W., 238
Negri E., 291, 592
Nelson G., 1103
Neri S., 749
Nesvacil N., 148, 242, 382, 646
Nevulis - Obuchovska V., 612
Newbold K., 519
Ng M., 1579
Ng W. T., 991
Nguyen C., 113
Nguyen D., 77, 625
Nguyen Huynh T. V., 1044
Nguyen T. V., 302, 1074
Niatsetski Y., 695
Niazi T., 1242
Nichols E., 1538
Nicolai M., 563
Nicolini G., 374, 400, 1438, 1480, 1544
Niedbala G., 828
Niehoff P., 220
Nielsen J., 249

Nielsen M., 326, 1361, 1382
Nielsen M. M., 1292
Nielsen M. S., 249
Nielsen S. K., 149, 296, 301, 384, 1077
Nielsen T. B., 1176, 1181
Niemelä J., 1543, 1562
Niemoeller O., 981
Niermann K., 1032
Nieto I., 1462
Nieto-Camero J., 1500
Nieto-Camero J. J., 420, 1428, 1496, 1498
Nieuwenkamp H., 1411
Niita K., 1419
Nijkamp J., 109, 169, 245, 248, 276, 1145
Nijkamp M., 132
Nijsten S., 533, 583, 809, 1117, 1541
Nikolajek K., 1001
Nikolova I., 157
Nill S., 209, 241, 418, 454, 1165, 1171, 1221,
1477, 1568
Nilsson K., 1252
Nilsson P., 181
Nisbet A., 425, 484, 812, 1112, 1162
Nishimura T., 729, 778
Nishimura Y., 1364
Nishioka A., 713, 777
Nishiyama K., 818, 918
Nishiyama T., 721
Nixon J. A., 990, 994
Niyazi M., 970, 981, 992, 1001
Niël C., 1184
Nkiwane K. S., 53, 54
Noble R., 1437
Noel A., 1212
Nogami M., 777
Nogaret J. M., 586, 601
Nomden C., 147, 153, 299, 636
Nordsmark M., 808
Nordström F., 1210, 1255, 1559
Norihiko K., 974
Norihisa M., 974
Norrlinger B., 388
North J., 496
Noterman D., 586, 601
nourollahi S., 1563
Nout R., 147, 299, 569
Novara G., 344
Novikov S., 759
Nowicka E., 719, 725, 1019
Noël G., 514
Nulens A., 147, 219, 792
Nundlall N., 1574
Nunez Quintanilla A. T., 1389
Nutbrown R., 1425
Nutting C., 60, 519, 1148, 1338
Nuver T., 214, 527, 701
Nuyts S., 332, 836, 850, 1120
Nuyttens J., 211
Nuzzo C., 840, 867
Nuñez A., 1413
Nuñez Fernandez M., 895
Nygaard A. D., 179
Nygård K., 1330
Nyholm T., 379
Nyiri B., 828
Núñez A. T., 1008
Núñez L., 102, 420, 1428, 1499
O hAllurain B., 1566
O Miochain B., 1337
O’Brien P., 637
O’Byrne K., 841
O’Callaghan C., 517
O’Connor D., 1522
O’Doherty U., 110
O’Dwyer D., 1292
O’Keeffe S., 1217
O’Leary G., 1031
O’MAHONY D., 841
O’Shea E., 1581
O’Sullivan B., 62, 851
O’Sullivan J., 72, 263, 453
O’Sullivan L., 1581
O’toole M., 683
Obata S., 1025
Oberije C., 274
Oberlin O., 295

S 604

Oberna F., 874
Obertacke U., 18
Oblak I., 957, 1068
Occhini A., 835
Ocvirk J., 1068
Oda M., 1096
Oechsner M., 1283
Oelfke U., 209, 241, 401, 418, 454, 1165,
1171, 1221, 1477, 1568
Ogawa K., 1369
Ogawa Y., 713, 777
Ogino R., 1552
Ogunremi T., 873
Oh J., 1512
oh R. J., 974
Ohashi T., 721, 1023
Ohlhues L., 398
Ohta Y., 1025
Ohtomo K., 246, 1175, 1266, 1333
Oita M., 1235, 1369
Ojala J., 439
Okano N., 883
Okano Y., 1198
Okayasu R., 1053
Okihara K., 729
Okuhata K., 1096
Okumura M., 1364
Okunieff P., 1145
Olaciregui I., 215, 1377
Oldham A., 632
Olejnik K., 725
Oliveira A. C., 1454, 1555
Oliver K., 1152
OLIVIER C., 1244
Olofsson J., 575
Olsson S., 71
Olszewska A., 1556
Olszyna-Serementa M., 1066
Olteanu A. M. L., 1190
Olvina M., 810, 1021
Omejc M., 1068
Ong C., 1238
Ong C. L., 370, 1526
Onoe T., 1198, 1266, 1296
Oonishi K., 1053
Ootsuka Y., 1235
Oplaat M., 1184
Opp D., 983
Ordeanu C., 495, 638, 664
Orecchia R., 8, 36, 269, 310, 312, 722, 763,
807, 1012, 1063, 1163, 1192,
1243, 1276
Orlandi E., 1262
Orlandini L., 1353
Orlandini L. C., 1352
Ormberg I. W., 1213
Ortholan C., 221
Ortiz de Urbina Ugarte D., 12
Orton C. J., 650
Ostapenko V., 612, 624, 774
Ostinelli A., 1409
Osztavics A., 288, 1504
Otal A., 1374, 1546
Otani Y., 781
Otto K., 465
Ottolenghi A., 122
Ottosson R., 433
Ottosson R. O., 1386
Ottosson W., 1258, 1507
Ouhib Z., 686, 733
Outif A., 1274
Overgaard J., 44, 116, 131, 136, 308, 515, 808
Overgaard M., 136, 208
Overhoff H. M., 748, 933
Owen P., 966
Oyekunle O., 661
Oyen R., 322
Oyen W., 1168
Oz Puyan F., 916
Ozard S., 709
Ozawa S., 860
Ozretic P., 770
Ozzello F., 741, 1004
Pacelli R., 1139
Pacilio M., 1170, 1394
Paganelli C., 1192

AUTHOR INDEX
Pagliara M., 294
Paglione F., 1378
Pagola Divasson M., 224, 289
Pai J., 625
Paiusco M., 1161, 1494
Palacios M., 1485
Palanichamy K., 938
Palanisamy S., 1138
Palazzi M., 863
Paliwal B., 578
Palloni T., 7
Pallotta S., 1423
Pallottini S., 1378
Palma D., 897
Palmans H., 49, 356, 966, 1112, 1134, 1425
Palmer A., 643
Palmer C., 1425
Palmer J., 959
Palmieri T., 1071, 1161
Palombarini M., 22, 595
Paluga M., 693
Palumbo A., 840, 867
Palumbo I., 762, 768, 1060
Pan T., 247
Panadés M., 625
Panarina N., 1085
Pancewicz-Janczuk B., 882
Pandha H., 425
Pandit S., 805
Panettieri V., 360, 399, 1147
Pang G., 1271
Panneman C., 996, 1225
Panshin G., 501, 896, 1453
Panta R., 1142
Pantano J., 672
Pantarotto J., 525
Pantazis D., 855
Pantelis E., 1087
Paolo P., 594
Paolucci M., 588
Papagiannis P., 352, 421, 1087
Papaiah Susheela S., 825
Papaleo A., 840, 867, 1003, 1041
Papanikolaou N., 402, 404, 424, 426, 1082,
1084, 1145, 1417, 1449
Pappalardi B., 500, 753
Paprota K., 167
Pardo Montero J., 371, 423
PAREDES COTORE J., 1055
Parisi A., 971
Parisi G., 971
Park J., 1054
Park J. H., 962
Park S. W., 833
Park T., 853
Park W. C., 752
Parker J., 1202
Parker R., 1554
Parkhurst J., 456, 1286
Parlar S., 916, 917
Parmiggiani M., 861, 1233, 1245, 1264
Parra-Robles J., 1290
Parry J., 1475
Partridge M., 95, 447, 448, 560, 1148, 1167,
1172
Parvanova V., 773, 1069
Parygina L., 986
Pasca E., 444
Pascal R., 182
Pascau J., 28, 29, 599
Paschalis T., 855, 1564
Pasciuti K., 1539
Pascoal A., 1531
Pasetti M., 753, 868
Pasler M., 1328
Pasquino M., 741, 1004
Passoni P., 552, 1049
Pastore G., 840, 867
Patel D., 938
Patel M., 536
Patel P., 1305
Patenaude V., 738
Patil A., 414
Patil N., 1006
Patiti M., 588
Patkar S., 1137
Pattinson J., 950

Patwe P., 1091
Pautier P., 567
Pawelke J., 563
Paz A., 1251
Pazos Alvarez A., 371
Pearce J., 103, 1117
Pearce L., 735
pearson R., 834
Peckham M., 490
Pedicini P., 663, 801, 1042, 1350
Pedretti S., 739, 952
Pedroli G., 1243
Peerawong T., 830
Peiffert D., 152
Peignaux K., 795, 800
Peignaux-Casasnovas K., 1078
Peintinger F., 3
Peleteiro P., 1055
Pellejero S., 652, 1374, 1546
Pellizzon A. C. A., 714
Penjweini R., 1164
Pentimalli S., 870, 921
Pepper K., 1424
Pera J., 824
pera J., 670
Peraza C., 12
Pereira L., 1088, 1100, 1365, 1367, 1462,
1482, 1493
Perez Aguilar D., 14, 15
PEREZ DE LUCIA G., 591, 604
Perez Moreno J. M., 1133, 1239, 1342, 1347,
1401, 1448, 1553
Perez Vara C., 1436, 1442
Perez Vega-Leal A., 428
Perez-Ordonez B., 851
Perna L., 396, 1332
Peroni M., 1192
Perrin R., 1172
Perrucci E., 762, 768
Perry G., 525
Persoon L., 533, 1117, 1541
Persson G., 1181
Peschke P., 1511
Pesznyak C., 1476
Peszynska M., 1571
PETE I., 658
Peters M., 1016
Peters P., 736, 1141, 1336
Petersen C., 317
Petersen I., 17, 34, 41
Petersen J., 172, 213, 377, 1285
Petersen J. B., 485, 506, 1186, 1194
Petersen P. M., 473, 908, 1241
Petersson K., 1250
Petit H., 514
Petitfils A., 178, 1078
Petitto R. P., 768
Petoukhova A., 20, 1349
Petric P., 52–54, 630, 654, 715, 957
Petrucci A., 7, 312
Pettingell J., 736, 1141, 1336
Pettit L., 879
Pfaffenberger A., 401
Pfeffer R. M., 782
Pham Y., 77
Phansekar R., 1142
Philippenko V., 787
Philippens M., 66, 260, 320, 446, 829
Philippson C., 586, 601
Phillips J., 1501
Phungrassami T., 830
Piani C., 478
Piatti P., 588
Piattoni S., 1060
Picardi M., 1139
Picardi V., 869, 1323
Piccinini J., 794
Picon O., 670
Piergentili M., 681
Piermattei A., 869, 1323
Pierrat N., 710
Pierre C., 333
Pieters B., 704, 723
Pietrzak L., 167, 1066
Pietta G., 739
Pietta N., 749
Pignol J. P., 81, 108

S 605

AUTHOR INDEX
Pignoli E., 1262, 1431, 1432
Pignon J. P., 192
Pigott K., 1009
Pilotti I., 1535
Pina F., 1092
Pinar B., 788
Pinkawa M., 1
Pinnaro P., 596
Pino F., 1109
Pinto G., 743, 1062, 1075, 1371
Pintye , 890
Pinza Molina C., 1488
Pinzi V., 1539
Piombino M., 1535, 1536
Piotrowski T., 282, 1200, 1236, 1358, 1435,
1439
Piperi M., 757
Piperkova E., 773
Piro F., 948
Piroth D., 1
Piroth M. D., 1
Pisani C., 641
Pisinger C., 183
Pitz C., 274
Piulats J. M., 670, 824
Piva C., 1327
Plasmati C., 835
Plasswilm L., 893, 902
Plewicki G., 719, 725, 1019
Ploquin J., 1451
Plotino G., 1536
Pobijakova M., 961
Podesta M., 809, 1117
Podolski P., 905
Poels K., 69, 210, 250, 455
Poelstra A., 748
Pointreau Y., 135
Polgár C., 230, 615, 658, 692, 874
Polgár I., 1476
Poli M. E., 1474
Polkowski W., 19, 167
Polo A., 14, 15, 676, 732
Polo Rubio J. A., 266
Poludniowski G., 461, 1319
Polyakov S., 708
Pommier P., 1294
Pompeo E., 279
Poncelet A., 440
Pontes M., 1560
Pontes M. S. B., 1531
Ponto L., 441
Poon J., 1318
Poortmans P., 182, 327, 1253, 1277
Popescu C., 77, 625
Popescu I. A., 433
Popov A., 986
Popov I., 1065
Poppe B., 1125, 1227
Popławska-Maksimowicz E., 924
Porcu P., 744, 1063
Porras I., 435
Porrato C., 794
Porta C., 835
Pos F., 476
Postma E., 168
Potrebko P., 407
Pouliot J., 696
Poulsen P., 1205
Poulsen P. R., 249, 251, 459, 535
Poulsen R. L., 111
Poupon E., 1472
Powell M., 553, 982
Pracy M., 731
Pradier O., 1166
Prado K., 406, 1538
Praestegaard L. H., 213
Prasad R., 1425
Prasath S., 1469
Pratissoli S., 1233, 1245
Presilla S., 737, 1307
Pressello M. C., 1170, 1352, 1353, 1394
Prest M., 1409
Preston S., 1204
Prezado Y., 1547, 1576
Price G., 244, 456, 1286
Price P., 244
Prieto Villacorta M., 1436, 1442

Primdahl H., 515
Primrose W., 866
Principi M., 1002
Prise K., 263, 453
Pritz J., 983
Provatopoulou X., 757
Provencher D., 302
Prtiz J., 758
Prudêncio L., 1560
Pruegsanusak K., 830
Præstegaard L. H., 1105
PS S., 609
Publicover J., 1031
Pudelek J., 1339
Puertas E., 1304
Pujades Claumarchirant M. D. C., 666, 1097
Pujades M. D. C., 686
Pujol C., 733
Pulay T., 658
punwani S., 1272
Pupillo F., 105
Purandare N., 793
Pursley J., 1470
Putter H., 165, 964
Puxeu Vaqué J., 1109, 1240
Pyatigorskaya V., 782
Pychlau C., 23
Pyrhonen S., 538
Pérez J., 689
Pérez L., 1244
Pérez Nieto F. J., 428
Pérez-Calatayud J., 421, 666, 686, 689, 696,
733, 1097
Pócza T., 1476
Pötter R., 53, 54, 148, 151, 190, 242, 269, 382,
554, 568, 646, 693, 1504
Pöttgen C., 1254
Qayum N., 1050
Qiu R., 967
Quagliani F., 1115, 1116
Quero L., 78, 975
Quesada J. M., 428
Quetin P., 152
Quinones-Hinojosa A., 1515
Quint S., 1201
Quirke P., 1050
Quirós Higueras J. D., 21
Quirós-Higueras J. D., 1392, 1486
Quon H., 1271
Raaijmakers N., 260, 829
Raaymakers B., 139, 240, 796, 937
Rabbani Z., 770
Racine M. L., 80
Raczek-Zwierzycka K., 798
Radhakrishna G., 679, 936
Radicchia V., 1034
Radkowski A., 167
Radu E., 1220, 1473
Radziszewski J., 167
Raffetto N., 802, 971
Ragona R., 1327
Rajevac V., 771
Ralston A., 373
Ramani V., 903
Ramani V. S., 1058
Ramella S., 279
Ramirez A., 1488
Ramirez E., 1520
Ramirez Ros J. C., 608, 1436, 1442
Ramm U., 1123, 1466
Ramos A., 29
Ramos Aguerri A., 14, 15, 676, 732
Rampino M., 1327
Rampling R., 822
Ramsay R., 755
Ramtohul M., 1132, 1460, 1501
Ramundo D., 1161
Rancati T., 177, 396, 559
Rancea A., 495, 638, 664, 673
Randazzo N., 1423
Rangarajan V., 133, 793
Rangaswamy G., 645
Rangel A., 1376
Rank M., 1305
Raoust I., 751

Rasch C., 109, 267, 272, 314, 468, 1145,
1183, 1261
Rasmussen J., 1558
Rath G., 674, 799, 805
Rathi A. K., 862
Rato A., 1532
Rauch D., 823
Rauco R., 1170, 1353, 1394
Ravinet L., 514
Ravkilde T., 251
Rawashdeh K., 677
Raymondi C., 762, 1370
Razaq S., 736, 1141
Rebuzzi M., 1116
Reerink O., 446
Regan P., 966
Reggiori G., 415, 481, 1128
Regine W., 406, 775, 1538
Regnault P., 656
Reidunsdatter R. J., 1149, 1415
Reilly A., 1223
Reinhardt S., 390
Reis Lima Marques M., 1062
Reis T., 18
Reis T. S., 1371
Reitan J. B., 1213
Reitsamer R., 2, 3, 312
Rekstad B. L., 1057, 1213
Remeijer P., 275, 458, 476, 531, 887, 996,
1225, 1261
Remonda L., 815
Ren Kaiser S., 1131
Reniers B., 81, 108, 147, 155, 300
Renner W., 910, 913
Repp N., 1197
Resch A., 382
Resubal J. R., 871
Resuli B., 971
Rey C., 1062
Reynaert N., 1325
Reynders T., 69
Rhein B., 1221
Ribas Morales M., 524, 1492
Ribeiro F., 1474
Ribeiro T., 1560
Riboldi M., 174, 532, 1192, 1218
Ricardi U., 741, 1004, 1327
Riccardo C., 552
Ricchetti F., 6Rich T., 271
Richards H., 1238
Richardson C., 650, 679
Richart J., 689
Richter A., 95
Richter C., 563
Richter P., 167
Rickard D., 812, 1162
Ricke A., 4, 11
Ricke J., 119
Rickhey M., 451
Rico M., 652
Riesterer O., 255, 405, 482
Rietveld P., 1362
Rigante M., 847
Righetto R., 1278
Riis H. L., 1445, 1481
Riise M., 1258
Rijnders A., 199
Rim C. H., 644
Rimmer Y., 1265
Rinaldi C. G., 640, 842
Rinaldi G., 1115, 1116
Rinaldin G., 1332
Rink A., 699, 1031
Rios Velazquez E., 471
Ripol , 747
RISHI A., 872
Rit S., 245, 248
Ritzen K., 1506
Rivard M., 154, 353, 922, 1080, 1089, 1542
Rivera M., 1008, 1389, 1413
Rivera R., 766
Rivera S., 78, 975
Rives M., 292
Rixham P., 1458, 1479
Rizvi S., 1510
Rizzo G., 48, 98, 507, 878

S 606

Robb M., 736, 1141, 1336
Roberto E., 588
Roberts N., 936
robinson M., 834
Rocco B., 36, 722
ROCH P., 1129
Roch P., 1127, 1130
Rocha F., 1454, 1555
Rocha H., 315
Rodemann H. P., 369
Rodrigues C., 389
Rodrigues G., 520, 897
Rodriguez I., 659
Rodriguez M., 38
Rodriguez R., 895, 1428
Rodriguez-Gallego C., 788
Rodriguez-Ibarria N., 631
Rodríguez M. E., 224, 289
Rodríguez Romero R., 1106
Rodríguez S., 689
Rodríguez-Bachiller L., 16
Roe G., 679
Roebben I., 836
Roeder F., 23, 33, 600, 602
Roeloffzen E., 82
Roelofs E., 393
Roermund J., 1037
Roesink J. M., 260, 829
Rogelj P., 715
Rogers D., 106, 378
Rogers S., 815
Rognone A., 868
Roldan S., 733
Rolfo M., 450, 1232, 1414
Romagnoli E., 1378
Romagnoli R., 22, 587, 595
Romero Exposito M. T., 422, 1494, 1496, 1497
Romero Expósito M. T., 420, 1428
Romero P., 652
Romestaing P., 170, 221
Rompokos V., 1207, 1368
Rondelli D., 1305
Rondi E., 36, 722, 807, 1063, 1163
Ronzino G., 840, 867
Roos D., 969, 973
Roques T., 557, 852, 858, 877, 894
Rosa M. J., 1532
Rosello J., 371
Rosenberg I., 1207, 1301, 1368, 1427
Rosenblatt E., 511
Rosenfelder N., 475, 1011, 1026, 1027, 1257,
1260, 1270
Rossi M., 96, 100, 101, 275, 887
Rossi R., 1002
Rostkowska J., 1455
Roszak A., 9
Rot San Juan M. J., 28
Roumeliotis D., 855
Roussou E., 1087
Routsis D., 112, 257
Rowbottom C., 316
Rowshanfarzad P., 1522
Roy S., 791
Royle G., 1207, 1424, 1427
Rozendaal R., 215, 526, 1185, 1377, 1464
Rozkowska E., 780
Rozza D., 763
Ruan D., 249
Rubbia-Brandt L., 1045
Rubin J., 853
Rubio A., 1374, 1546
Ruchaud R., 137, 389
Ruggieri M. P., 1071
Ruiz Arrebola S., 1484
Ruiz Rodriguez J. C., 593
Ruiz Úcar E., 16
Runz A., 602, 1173
Rusen C., 916, 917
Ruskó L., 1570
Russi E. G., 19, 816
Russo A., 1461
Russo D., 840, 867, 1003, 1041
Russo G., 597
Russo M. T., 1461
Russo S., 1378
Rusu P., 278
Rutgers E., 207

AUTHOR INDEX
Rutkowska E., 180
Rutkowski A., 1066
Ryan G., 947
Rychter A., 167
Ryczkowski A., 282, 1358, 1439
Ryhanen A., 538
Rylander S., 445
Rödel C., 94, 1123, 1466
Röhner F., 1193, 1491
Rødal J., 189, 442, 1158
Rønde H. S., 377, 1105
Sabater S., 1008, 1389, 1413
Sabatino D., 869, 1323, 1461
Sabet M., 1395, 1522
Sacchetti G., 926
Saccia S., 889, 1378
Sacco S., 697
Sadeghi M., 1388
Sadoughi H., 1366
Saez J., 1340
Sagthong R., 830
Saha S., 613
Sai S., 1053
Saiani F., 277
Saidi Bidokhti P., 1388
Saito S., 721
Sakai T., 1096
Sakamoto K., 1096
Sakanaka K., 923
Sakas G., 687
Sakelliou L., 1087
Sakumi A., 246, 1175, 1198, 1266, 1333
Sakurai H., 161
Salas Buzon C., 629
SALAS BUZON M. C., 671
Saleh Z., 134
Salehi Yazdi H., 1086
Salem A., 820, 928
Salenius S., 884
Salgado Fernandez M., 1088, 1100
Salgado M., 1365, 1367, 1462, 1482, 1493
Salisbury A., 826
Sallabanda Díaz K., 12
Salustri P., 889
Salvador F., 1100, 1367
Salvatore M., 1139
Salvi F., 499
Samanci A., 1036
Samant R. S., 828
Samblas J., 12
Samerdokiene V., 651
Sammarco M. G., 294Samsøe E., 865
san José S., 1304
San Julian M., 224
San Miguel I., 224, 289
Sanchez C., 652
Sanchez del Campo I., 14, 15
Sanchez Iglesias A. L., 1392
Sanchez-Doblado F., 102, 420, 422, 423,
1099, 1104, 1113, 1428, 1494,
1496–1500
Sanchez-Nieto B., 920, 1494
Sancho García S., 14, 15, 676, 732
Sandle S., 812
Sandler H., 536
Sangalli C., 1262
Sangalli G., 697, 1372
Sanghera P., 873, 879
Sangster N., 632
Sanguineti G., 98, 507, 816, 1144
Sankreacha R., 231
Sanne C., 1314
Sansaloni F., 102, 420, 1428, 1498, 1499
Santa Cruz O., 702, 1092
Santanam L., 1298
Santantonio M., 840, 867, 1003, 1041
Santiago A., 1421
Santini E., 1170, 1353, 1394
Santoni R., 1115, 1116
Santoro A., 415, 870
Santoro L., 763
Santos A., 589
Santos J., 1169
Santos M., 585, 623, 689
Santos M. A., 290

Santos Miranda J. A., 28, 29, 599
Santos Serra A., 21, 1486
Santos-Serra A., 1392
Saotome N., 246, 1175, 1198, 1266, 1333
Saoudi A., 186, 779
Sapru W., 1309
Saran F., 74, 1314, 1320
Sarcevic B., 770
Sari I., 1425
Sarmento C., 1062
Sarmiento T., 810, 1021
Sarra Fiore M., 763
Sarrabayrouse G., 1457
Sarrut D., 532, 1218, 1385
Sasai K., 860
Sasaki T., 777
Sasso G., 1561
Satheesan B., 647
Sathyanarayanan V., 980
Sato T., 1419
Satou M., 1234
Satou T., 1234
Sauerwein W., 1390
Saunders C., 614
Saunders M. I., 191
Sauthier P., 302
Sawant A., 249, 1204
Saynak M., 916, 917
Scalco E., 98, 507, 878
Scalliet P., 173
Scambia G., 640
Scandurra D., 1219
Scaringella M., 1423
Scarzello G., 1251
Scepanovic D., 961
Schaake E., 276
Schaapveld M., 1037
Schaeken B., 1325
Schaerer J., 532, 1218
Schakel T., 260, 320, 829
Schalken J., 364
Scheenstra A., 101
Scheib S., 535
Schell S., 409
Scherer P., 329
Scherf C., 1123, 1466
Schettino G., 453
Scheuch J., 382
Schick U., 1027, 1257
Schiestl B., 1459
Schilstra C., 184, 410, 411, 1356
Schincariol A., 1440
Schippers M., 561, 636, 796
Schleicher S., 1032
Schlenvoigt H. P., 563
Schmid M., 148
Schmidt R., 18
Schmitz A., 309
Schmucker M., 1491
Schmuecking M., 823, 893, 902
Schneider C., 248
Schneider F., 10, 18
Schneider R., 521, 977
Schneider T., 171
Schneider U., 125
Schniewind B., 220
Scholten A., 483, 1277
Schombourg K., 737, 1307
Schouboe A., 330, 1509
Schramm O., 600
Schramm U., 563
Schubert K., 1568, 1580
Schulze J., 1171
Schumacher C., 4, 11
Schumacher J., 220
Schuring D., 324
Schuster T., 844
Schwahofer A., 600, 1221
Schwartz A., 13
Schwarz M., 256, 277, 1196, 1211
Schwarz S., 970, 992
Schweikard A., 140
Schytte T., 326, 912
Schürer M., 563
Sciacero P., 741, 1004
Scorsetti M., 415, 481, 870, 921, 1128
Scotti V., 277

S 607

AUTHOR INDEX
Scrase C. D., 1015, 1554
Scricciolo M., 768
Sculier J. P., 204
Scupola A., 294
Seabrook M., 1416
Sebag-Montefiore D., 46, 679, 936
Sebastian E., 618
Sebestyen K., 1551
Sebestyén Z., 1523, 1551
Seco J., 1192
Sedlmayer F., 2, 3, 19, 312, 329, 331, 945,
1118
Segedin B., 630, 654, 715, 957
Seiersen K., 111
Sekine H., 781
Selbach H. J., 171
Selvadurai E., 1311
Selvaraj J., 97
Semiglazov V., 759
Sempau J., 1547
Sempere P., 998, 999
Senan S., 370, 897, 1526, 1529
Sendiuliene D., 624
Sener S., 756
Sengoz M., 616, 1199
Sengul A., 541
Senkesen , 616, 1199
Senny F., 1182
Seoane A., 694, 1340
Seppenwoolde Y., 534
Seravalli E., 1256
Serrada A., 659
Serrano J., 38, 39
Serrano Navarro C., 25
Sesek M., 715
Seuntjens J., 104, 525
Sevillano Capellan M., 1008, 1413
Sevillano D., 464
Sezer A., 919
shabani H., 1086
Shadchehr S., 672
Shah A., 1230
Shah C., 75, 618
Shah K., 826
Shah K. A., 826
Shah M. A., 1070
Shakirin G., 412
Shalaby I., 904
Sham J., 1011
Shamurailatpam D., 1224
Shao Q., 987
Sharif A., 1153
Sharma D., 805
Sharma D. N., 674, 799
Sharma R., 619, 968
Sharma R. A., 1050
Sharp G. C., 1192
Sharpe P., 23, 376
Sharrock P., 456, 1286
Shehi B., 907, 952
Shekhar S., 862
Shen S., 150
Shen W., 967
Shenoy A., 1240
Sherriff J., 873
Sheth P., 766
Shi C., 402, 426, 1449
Shigematsu N., 721, 1023
Shikata T., 914
SHIMO T., 1047
Shimomura K., 1364
Shin J. W., 833
Shin S. H., 1093, 1446
Shino R., 1296
Shiomi H., 974
Shipley D., 103, 966, 1112, 1117, 1425
Shipley W. U., 536
Shiraishi K., 1198, 1266, 1333
Shiraishi Y., 721
Shirazi A., 1388
Short S., 425, 827, 911, 982, 1310
Shridhar R., 983
Shrimali R., 668
Shrivastava S. K., 160, 297, 634, 791, 793,
1189
Shuin T., 713
Shukla P., 1189

Shum L., 1033
Siciliano R., 948
Sidhu N., 375, 1064, 1126
Sidhu S., 1433
Sidi V., 990, 994
Siebers J., 258, 281
Siebert F. A., 220, 225, 688
Siedschlag C., 96
Siekkinen M., 538
Sierko E., 882, 924
Signor M., 499
Sihver L., 123, 340, 1419
sikora K., 1229
Silva J., 1532
Silvano G., 1540
Silyvridou A., 855, 1059, 1061, 1067, 1564
Simmat I., 469
Simon L., 333
Simon S., 586, 601
simoncini E., 739
Simpson J., 1344, 1561
Singh A., 803
Singh D. P., 619
SINGH H., 803
Singh K., 862
Singh S., 803
Singh Wadhawan G., 1502
Siniscakchi A., 40
Sinkó D., 1476
Siochi A., 1533
Sioshansi S., 1080
Sipahi T., 756, 886
Sipila P., 1543, 1562
Sire C., 135
Siu L., 851
Sivabalasingham S., 1310
Sjöberg J., 479
Sjöström D., 419, 479, 1258
skailes G., 804
Skeates L., 709
Skikiewicz M., 1475
Skjei Knudtsen I., 1158
Skorska M., 1439
Skottner N., 1410
Skowron J., 1421
Skowronek J., 79, 351, 626, 724, 730, 734
Skretting A., 1158
Skripchak Y., 888
Skrobala A., 1358
Skrobała A., 978
Sladowska A., 1339
Slagmolen P., 322, 332
Slim N., 552, 753, 1049
Sloane P., 817
Slobina E. L., 708
Slosarek K., 118, 487, 617, 1140, 1447
Slotman B., 270, 370, 1526, 1529
Small C., 1581
Smaniotto D., 294, 640
Smeenk R. J., 447, 1230
Smit K., 139, 937
Smith B., 1305
Smith D., 936
Smith H., 942
Smith M., 1412
Smith S., 316, 1322
Smith-Bronson V., 766
Smits G., 223
Smol S., 978
Smolska-Ciszewska B., 719, 725, 1019
Smulders B., 1309, 1321
Smyth G., 1313
Smyth M., 853
Smyth V., 122
Soares A. F., 1532
Sobat H., 771, 1014
Sobotta C., 933
Soevik A., 442, 1514
Soisson E., 104
Sola A., 652
Solak Mekic M., 1014
Solaric M., 771, 1014
Solberg T., 477, 1520
Sole J. M., 895
Soler P., 290, 623
Soler Tortosa M., 849, 995
Solero C. L., 953, 976

Solis J., 925
Solla R., 1139
Sollén F., 121
Solodki V., 501
Sommer R., 1238
Son K., 1093, 1446
Song H., 1515
Song S. Y., 962
Sonke J. J., 100, 101, 197, 215, 245, 248, 268,
275, 276, 309, 313, 391, 444,
458, 468, 526, 530, 887, 1159,
1180, 1183, 1185, 1225, 1261,
1377
Soomal R., 1051
Sorcini B., 927
Soria A., 28
Soria J. C., 127, 567
Soriani A., 24, 26, 27, 30, 596
Sotnikov V., 896, 905
Soto P. M., 1374, 1546
Sotti G., 906
Soumarova R., 87
Sousa O., 1169
South C., 1167, 1172, 1249, 1299
Southgate E., 1222
SP G., 609
Spadea M. F., 1192, 1276
Spagnoletti G., 1535, 1536
Spahn-Horn S., 398
Span P., 132
Sparchez Z., 673
Specht L., 136, 181, 473, 908, 1297, 1309,
1321
Speleers B., 188
Spezi E., 380, 522, 1220, 1473
Spiazzi L., 277
Spiccia P., 597
Spoto R., 722
Spreeuw H., 1464
Springer C., 709
Spry N., 496, 1143
Spyrakos M., 855
Squillace L., 835
Sroka-Perez G., 1173, 1568, 1580
St-Hilaire J., 417
Stacey C., 1272, 1301
Stafford S., 17
Staffurth J., 1220
Stahiescu R., 638
Stam M., 139
Stancampiano C., 1423
Stanescu T., 480
Stapor-Fudzinska M., 1447
Stasi M., 954
Stassen L., 841
Stathakis S., 424, 1449
Stawicki M., 1157
Stearns V., 750, 767
Steenbakkers I., 1208
Steenhuijsen J., 324
Stefania C., 1350
Steggerda M., 88
Steigler A., 496
Steiner E., 1024
Steininger P., 1118
Steininger T., 381
Stellamans K., 1090
Stenbeck J., 238
Stephans K., 243
Sterpin E., 1396
Stevens C., 1157
Stevenson P., 843
Stewart D., 866
Stewart F., 347
Stierle C., 312
Stock M., 381, 469, 1024, 1215, 1504
Stoiber E. M., 1196, 1211, 1288
Stojanovic-Rundic S., 1065
Stoll A., 418
Stoner N., 950
Stranex S., 72
straney M., 683
Stranzl H., 1209
Stratford J., 244
Stratton R., 911
Straube W., 1298
Stravato A., 1394

S 608Streeter O., 764
Streller T., 467
Strickert T., 1149, 1415
Strigari L., 24, 26, 27, 30, 596, 1115, 1116,
1352
Strnad A., 227
Strnad V., 227
Stroian G., 222, 740
Stronach I., 935, 1574
Stroom J., 96, 215, 309, 1377
Struikmans H., 20, 86, 510, 1506
Stserbakov V., 528
Stucchi C., 1262, 1431, 1432
Studer G., 467, 1578
Stump K., 1542
Sturdza A., 53, 151, 242, 646
Stuschke M., 1254
Su J., 967
Suchorska B., 970
Suchowerska N., 107, 373, 1510
Sudha A. S., 814
Suetens P., 332
Sugimoto S., 860
Suh T. S., 833
Sullivan K., 1272, 1301
Sultan I., 677
sultanem K., 740
Summers H., 936
Sumo G., 1573
Sun Myint A., 1058
Sund Solli K., 1415
Sundset M., 54
Supper C., 333
Sur R., 1284
Sut N., 919
Sutherland R., 755
Suzer T., 1524
Suzuki K., 777, 781
Suzuki O., 818, 918
Suzuki Y., 777
Sveistrup J., 985
Svensson H., 503
Svetlana D., 785
Swamy K., 825
Sweldens C., 792
Swift S., 650, 936
Swinscoe J., 1290
Sydes M., 447, 448
Syed A. A., 1070
Sykes J., 936, 1295
Sylvestre M. P., 1044
Symon Z., 782
Syndikus I., 180, 903, 1029
Syrymbet Kyzy Z., 1035
Szabó J., 857
Szabó Z., 230
Szalai T., 1476
Szczepkowski M., 167
Szczurek L., 1331
Szeto Y., 1225, 1377
Szigeti A., 1523, 1551
Szlag M., 617, 662, 725
Szluha Lazanyi K., 890
Szymil A., 607
Szántó E., 1570, 1572
Sánchez N., 1340
Söhn M., 262, 506, 992
Søndergaard J., 915
Sørensen M., 172
Sørensen T. H., 419
Sørensen T. S., 1077
Sütterlin M., 590
tabarelli P., 744
TABOADA VALLADARES B., 1055
Taccini G., 24, 32, 105, 598, 669, 909, 1530
Tachibana H., 1234
Tadokoro M., 777
Tagliaferri L., 294, 640
Tai A., 175
Takacsi-Nagy Z., 874
Takada Y., 914, 1096, 1552
Takahashi S., 1369, 1467
Takaki S., 1039
Takanen S., 971
Takashi M., 923
Takatsuki H., 1025

AUTHOR INDEX
Takavar A., 1101
Takegawa H., 818
Talamonti C., 1423
Talapatra K., 1224
Tambe C., 1463
Tamburi F., 1378
Tamim N., 222, 740
Tamura K., 713
Tamura M., 1364
Tan L., 642
Tan L. T., 660
Tanaka K., 856
Tanaka T., 972
Tanderup K., 53, 54, 149, 296, 301, 384, 554,
1077
Tang C., 1202
Tangco E., 810, 1021
Tanner M., 600
Tanooka M., 914, 1096
Taouk Y., 947
Taphoorn M., 964
Tarabuzzi R., 37
Taright N., 78
tartaglione T., 847
Tasigiannopoulos Z., 877, 894
Tateoka K., 1467
Tatsumi D., 1552
Taussky D., 83, 1044, 1074
Taychasiraprapakul A., 1510
Taylor C., 194, 1292
Taylor H., 74, 1187
Taylor K., 1338
Taylor M., 1136, 1398
Tchakarova A., 773
te Veluwe I., 1237
Tedeschi D., 238
Teijeiro A., 1365
Teijeiro Garcia A. G., 1088, 1100, 1462
Teixeira N., 1531, 1532, 1560
Telguziueva Z., 787
Teo P., 1318
Teoh M., 812
ter Beek L., 1263
Terhaard C., 132, 260, 829
Terlizzi A., 1540
Tero A. T., 1154
Terribile D., 776
Terribilini D., 610, 1391, 1399
Terrone C., 37
Terrón J. A., 102, 420, 422, 1104, 1428, 1494,
1496–1499
Testolin A., 900
Tezcanli E., 616, 1199
Thakur M., 793
Tharavichitkul E., 53
Thebaut J., 438
Theil J., 808
Theuws J., 324
Thibault I., 156, 1242
Thirion P., 566, 1581
Tho L., 822
Thomadsen B., 1542
Thomas C., 1145, 1403
Thomas F., 333
Thomas G., 543
Thomas K., 1257
Thomas L., 152
Thomas M., 461, 1319
Thomas R., 376, 966, 1425
Thomas S., 387, 1265
Thompson C., 1383
Thompson K., 943
Thompson R., 521
Thomsen J. B., 249
Thomsen M. S., 308, 1509
Thomson M., 539
Thomson R., 56, 154Thor M., 99, 506, 1285
Thorley K., 735
Thornberg C., 1210, 1255
Thornton J., 158
Thorstad W., 134
Thorwarth D., 1167, 1168
Throuvalas N., 855
Thulkar S., 674
Thurner E. M., 910, 913
Thurzo L., 1495, 1572

Thwaites D. I., 342, 375, 691, 951, 1126, 1295,
1383
Thériault D., 372
Thörnqvist S., 445, 506, 1186
Thøgersen E. H., 485
Tian D., 931
Tielenburg R., 215, 1377
TIffany M., 1574
Tiffany M., 1460
Tille J. C., 1045
Timke C., 23, 33, 600, 602
Timmerman C., 1520
Timmerman R., 1520
Timon C., 841
Timon G., 6
Tini A., 255
Tisaire Sanchez J. L., 585, 998, 999
Tissen D., 533
Tiwari M., 1142
Tkachev S., 1453
Tobias J., 311
Todor D., 628
Todor N., 278, 495, 638, 955
Toepfer M., 893, 902
Tofani S., 741, 1004
Toft-Jensen P., 1258, 1505
Tokuhiro S., 777
Tolento G., 861, 1233, 1245, 1264
Tolley M., 1425
Toma-Dasu I., 1402
Tomic N., 1242
Tomoko M., 1552
Tomé W., 1283
Tonn J. C., 970
Tonoli S., 277
Topczewska-Bruns J., 780, 882
Torma J., 1373
Tormo A., 696, 733
Torre G., 1139
Torre T., 1251
Torrente S., 592
TORRES J. J., 1244
Torresin A., 437, 863
Tortajada-Azcutia M., 290, 623
Tortochaux J., 135
Tortoreto F., 177
Torzilli G., 921
Toscas I., 965
Toshihiko I., 974
Totaro G., 875, 1275
Tournel K., 69
Toustrup K., 515
Tovar Martin I., 631
Tover N., 1151
Toya K., 721
Tozzi A., 481, 870, 921
Traila A., 638
Trainor C., 263
Travaini L. L., 1163, 1276
Trebossen R., 1418
Trela K., 118, 487, 772
Tremblay D., 417
Trent S., 653
Treur S., 1302
Trevisan F., 907
Triggiani L., 907, 952
Trigolosov A., 1048
Trinari S., 1378
Trippa F., 1002
Tripuraneni P., 1298
Trnkova P., 285, 693
Trodella L., 279
Trompier F., 1127, 1129, 1130
Troost E., 1168
Trop I., 80
Trott K., 124
Trott K. R., 122
Truc G., 178, 795, 1078
Truong P., 77, 625
Tryggestad E., 141
Tsang Y., 394
Tsang Y. M., 395, 486, 1583
Tsangaris T., 750, 767
Tsao J. R., 1324
Tsao M. N. Y., 520
Tsikai N., 784
Tsuboi K., 914

S 609

AUTHOR INDEX
Tsubokura T., 729, 778
Tsujii H., 163
Tsujimura T., 914
Tsutsumi S., 1552
Tsuzuki A., 777
Tuchais C., 135
Tudor S., 387, 1265
Tuli R., 141
Tunesi S., 641
Tunstad J. H., 1408
Turan N., 917
Turco E., 861, 1233, 1245, 1264
Turner S., 496
Turri L., 37, 592
Turska J., 1094
Tuttolomondo G., 794
Tveit K. M., 1057
Tyc-Szczepaniak D., 1066
Tzikas A., 1417
Tzonevska A., 773
Uchida N., 972, 1467
Udowicz M., 1150
Uhl M., 33
Uiterwaal H., 542
Upasani M., 793
Uppal B., 876
Upreti R. R., 293, 414
Uray M., 1206
Urbanczyk H., 1140
Urbanski J., 880
Uregen B., 917
Usta U., 919
Ustun F., 916
Usychkin S., 12, 585
Uyterlinde W., 100Uzal M. C., 756, 916, 917, 919
Uzan J., 97
Uzcanga M., 185
Vachhrajani H., 1064
Vaezzadeh S. A., 932, 1086, 1111, 1366, 1393
Vagge S., 898, 909
Vaidya J., 311
Vaidya M., 1512
Valdagni R., 177, 396
Valdivieso M., 28
Valenti M., 1278
Valentini V., 19, 47, 130, 312, 393, 776, 842,
845–847, 869, 997
Valkov M., 888, 986
Vallancien G., 710
Vallazza E., 1409
Vallejo Ocaña M. C., 14, 15, 676, 732
Vallentin S., 1258
Vallerga F., 669
Vallis K. A., 826, 1354
Valuckas K. P., 612, 624, 651, 774
Valzana S., 926
van ’t Veld A., 410, 427, 429, 1282
van As N., 1011, 1026, 1027, 1257, 1260,
1270
van Asselen B., 745, 1195
van Baardwijk A., 96
Van Beek K., 859
van Beek S., 1261
Van Brussel S., 219
Van de Bunt L., 745
Van de Kamer J., 314, 531, 636
van de Kamer J., 1159
van de Schoot A., 472
van de Velde C., 47, 165
van de Water T., 184, 410, 411
van den berg A., 508
van den Berg C., 829
van den Berg N., 321
Van den Bergh L., 322, 327, 1253
van den Bongard D., 745
van den Bosch M., 121, 745
van den Ende P., 132
Van den Heuvel F., 123, 225, 319, 327, 1120
Van den Weyngaert D., 1325
van der Geest A., 447
van der Grient H., 704
van der Heide U., 66, 320, 321, 472, 498, 796,
1016, 1037, 1259
van der Hulst P., 410

van der Kogel A., 132, 339
van der Laan H. P., 184, 216, 410, 1356
van der Laarse R., 704
van der Meer S., 529, 1208, 1256
van der Molen A., 701
van der Poel H., 88, 1037
van der Putten W., 577
van der Salm A., 268
van der Sangen M., 1277
van der Sijp J., 20
Van der Sluis R., 1377
Van der Steen-Banasik E., 54, 223
van der Stoep J., 268
van der Voort van Zyp N., 211
van der Wal E., 1506
van der Zaan C., 1263
van der Zee A., 570
van Deursen M., 1016
van Dieren E., 1237, 1238
van Diest P., 745
Van Dongen G., 304
van Duinen S., 964
Van Dyk S., 633
Van Egmond J., 510
van Egmond J., 1362
van Elmpt W., 232, 268, 391, 412, 576, 583,
809, 1117, 1157, 1283, 1541
Van Gestel D., 466
van Gils C., 498
van Gils F., 1256
Van Gompel G., 250
Van Herck H., 332
van Herk M., 100, 101, 176, 215, 245, 248,
314, 412, 413, 468, 476, 526,
530, 531, 723, 887, 1159, 1183,
1185, 1225, 1281, 1377, 1464,
1556
van Herpt H., 184, 410
van het Loo M., 1468
van Hoof S., 809
Van Houtte P., 586, 601
van Kollenburg P., 1351
van Kranen S. R., 468, 1183
van Leerdam M., 498
van Leeuwen R., 153
Van Limbergen E., 53, 54, 147, 219, 554, 792,
836, 850, 1120
van Lin E., 447, 1230
van Lindert E., 1351
Van Loon J., 96
Van Ngoc Ty C., 1418
van Oort I., 1037
van Osch M., 321
van Piggelen H., 1281
Van Poppel H., 322
van Rooij P., 711
van Santvoort J., 964, 1349, 1506
van Seters R., 1411
van Stiphout R., 168
van Vliet-Vroegindeweij C., 217, 313, 1277,
1556
van Vliet-Vroegindewij C., 253, 1298
van Vulpen M., 66, 82, 121, 139, 320, 321,
472, 498, 745, 1016, 1037, 1259
van Werkhoven E., 207
Van Wieringen N., 328
van Wieringen N., 704
van Wingerden K., 20
Vance W., 621
Vandecasteele J., 1119
Vandecaveye V., 332, 836
Vandekerhove C., 601
vandekerkhove C., 586
Vanderstraeten R., 137
Vandervoort E., 1407
Vanetti de Palma E., 374, 400, 1438, 1480,
1544
Vanni A., 1046
Varga S., 658
Varga Z., 1495, 1570, 1572
Vargas Arrabal M. D. P., 631
Vargas Castrillón S., 1567
Vargas E., 965
Vasconcelos A. L., 1092
Vasishta V., 1000
Vautrin M., 1576
Vavassori A., 36, 722, 807, 1012, 1063, 1163

Vavassori V., 177, 396, 499
Vazquez J., 1100, 1365, 1462, 1482
Vazquez-Quino L. A., 426
Vecchio F. M., 1060
Vecchio S., 816
Vega Fernandez J. M. D. L., 1484
Velardi R., 587
Velasco Sánchez E., 16
Velenik V., 957, 1068
Venables K., 486
Vengalil S., 1033
Venkitaraman R., 1015
Venselaar J., 421, 1542
Ventura T., 1465
Verbakel W., 370, 1526, 1529
Verbeek-de Kanter A., 20
Vercauteren T., 1190
Vereb B., 1570
Vereczkey I., 658
Verellen D., 69, 138, 210, 250, 455, 466
Veresezan O., 955
Verga E., 875, 1275
Verhaegen F., 57, 81, 108, 154, 155, 300, 529,
533, 583, 728, 809, 1117, 1208,
1256, 1541
Verheij M., 165
Verhenne E., 1090
Verkooijen H., 796
Veronesi U., 8
Verschoor G., 1456
Verstraete J., 173, 327, 1253
Verzini G., 768
Vestergaard A., 330, 485, 1105
Veys I., 586, 601
Vial P., 113, 1345
Vianello F., 906
Vicedo A., 371
Vicini F., 75, 618, 628, 1022, 1028
Vidali C., 749
Vidiri F., 7
Vieillevigne L., 333
Vigna L., 926
Vigneault E., 698, 705, 707
Vigorito S., 807, 1012, 1063, 1163
Vijande J., 686
Vijlbrief R., 215, 1377
Vikström J., 1216
Vila M., 185, 652, 760
Vilarino-Varela M., 1009
Vilches M., 1484
Villa E., 753, 868
Villa S., 396, 727
Villafranca Iturre E., 185, 652
Villanego Beltran I., 627, 629
Villas M. V., 1008, 1413
Villegas-Mendez S., 764, 766
Villà Freixa S., 965
Vinall A., 1456
Vinante L., 906
Vini L., 1059, 1061, 1067
Vinikovetskaya A., 703
Viola P., 869
Visscher K., 1545, 1550
Visser P., 1208, 1256
Visser R., 427, 429
Visvikis D., 247, 1166
Vliet van - Vroegindeweij C., 458
Vock J., 823
Vodusek A. L., 957
Voet P., 318, 1201, 1343
Vogel W., 571
Vogelius I. R., 179, 181, 908, 1292
Volegova-Neher N., 1193
Volken W., 380, 1384, 1391, 1399
Volpe A., 37
Voncken R., 1256
Vozenin-Brotons M. C., 348, 567
Vreeken H., 695
Vreeswijk S., 458
Vujaskovic Z., 770
Vuong T., 222, 740, 1242
Vynckier S., 212, 392, 1396
Vásquez Osorio E., 534
Vásquez Torres A., 1173
Vázquez Rodríguez J. S., 1088
Vízkeleti J., 658

S 610W.Kratky K., 1164
Wachowicz K., 480
Wada M., 450, 1232, 1414
Wadi-Ramahi S., 677
Wagenknecht K., 23, 602
Wai E., 738
Wai P., 1313
Wakil G., 710, 761
Waldron J., 851
Waligorski M., 1339
Walker A., 255, 482, 1578
Walker C., 645, 958
Wallace M., 75, 229, 618
Wallis A., 113, 1345
Walsh K., 736, 1141, 1336
Walsh L., 635, 645, 655
Wanders S., 533
Wanet M., 440
Wang C., 775
Wang J., 685, 931, 967
Wang W., 742
Wang Y., 388, 931, 967, 1324
Ward A., 1425
Wareing T., 154
Warenczak- Florczak Z., 9
Warner N., 930
Warren S., 1188
Warren-Oseni K., 1187
Warrener K., 373
Warrington A., 1313, 1314, 1320, 1434
Warrington J., 1334
Waters B., 1574
Watkins G., 244
Wattez N., 939
Wauben D., 427, 429
Webb S., 196, 342, 447, 448, 461, 1172, 1319
Weber C., 1215
Weber D. C., 182, 392, 977, 1045
Wee W., 1293
Wei X., 233
Weichenberger H., 1118
Weil M., 434
Wein B., 1
Weinreb I., 851
Weisz C., 1476
Welleweerd H., 542
Wells D., 738
Wells E., 395, 1583
Welzel G., 18, 590
Wenz F., 10, 18, 311, 590
Wenzl T., 1426
Werner J., 33
Wesolowska I., 1140
Wessels C., 1477
Westberg J., 1481, 1483
Westbury C., 911Westendorp R., 214, 527, 701
Weston S., 375, 523, 951, 1126, 1430, 1458,
1479
Weynand B., 440
Whelan T. J., 206
Whilde N., 1489, 1490
Whitaker S., 812, 1162
White M., 717
Whitfield G., 244, 1286
Whitney D., 622, 660
Whittle K., 1156
Widmark A., 365
Wiegel T., 336
Wierts R., 325
Wierzbicki M., 1284
Wierzbicki R., 167
Wieslander E., 1329
Wiggenraad R., 964, 1349, 1362
Wiinholdt D., 183
Wijkstra H., 723
Wijrdeman H., 542
Wijsman B., 327, 1253
Wikström K., 1252, 1330
Wiktor N., 706
Wilbert J., 95
Wild J., 1290
Wilkens J., 390, 409, 1426
Wilkins R., 107
Wilkinson J., 516
Wilkinson J. B., 618
Willborn K., 1125, 1227

AUTHOR INDEX
Willems N., 1195
Williams J., 350
Williams M., 112, 546
Williams N., 311, 614
Williamson A., 988
Williamson J., 154
Williaume D., 800
Willich N., 312
Willis D., 1311
Willis N., 843
Wilsdon J., 843
Wilson C., 516, 622
Wilson G., 388, 1373
Wilson S., 936
Windhorst A., 304
Winiecki J., 1360
Winkler P., 1206, 1209, 1226
Winship A., 657
Winter C., 255, 482, 1578
Winter H., 1363
Wirtz H., 1328
Wist E., 1213
Wit F., 1263
Witte M., 176, 314, 412, 413
Witteveen T., 88, 476
Wittig A., 1390
Wlodarczyk H., 9
Woithe J., 563
Wojtukiewicz M., 882
Wojtukiewicz M. Z., 924
WOLF D., 1212
Wolff A., 750, 767
Wolfrat M., 996
Wolthaus J., 542
Wong H., 903, 1029, 1058
Wong Hee Kam S., 975
Wong J., 141, 243
Wood K., 812
Woods K., 813
Woolley A., 936
Workman G., 683
Worku M., 425, 827, 1310
Worm E., 249, 251, 459
Woudstra E., 1343
Wouters B., 303
Wouters J., 533
Wowra B., 1001
Wright B., 238
Wu W. C. V., 187, 1341
Wu Y., 1335
Wygoda A., 901
Wygoda M., 901
Wylie J., 1308
Wynne C., 496
Wyrwicz L., 1066
Wysocka-Rabin A., 31
Xia P., 243
Xiao J., 832
Xie J., 635
Xie X. (., 655
Xing J., 1269
Xu C., 728
Xu H., 755
Xu J., 1449
Xu M., 1269
Xynos E., 1059, 1061
Yagci M. A., 919
Yahalom J., 166
Yahara K., 929
Yalcin O., 756
Yamada M., 1369, 1467
Yamada S., 1053
Yamaguchi S., 1013
Yamamoto J., 1039
Yamamoto K., 1266
Yamamoto M., 856
Yamanishi T., 777
Yamasaki I., 713
Yamashita H., 246, 1175
Yamashita S., 1023
Yamashita T., 1096
Yamazaki H., 729, 778
Yampolsky H., 1521
YAN J., 655
Yan J., 635

Yan M., 755
Yan Y., 755
Yang D. S., 644
Yang J., 931
Yang R., 685
Yang X., 535
Yang Y., 1080, 1089
Yang Z., 1341
Yano S., 972
Yaogawa S., 777
Yarahmadi M., 932, 1393
Yarnold J. R., 236, 394, 911
Yasuharu S., 1110
Yasumasa K., 1096
Ye H., 229, 1020, 1022, 1028
Yeginer M., 1305
Yi B., 406, 1538
Yi B. Y., 1402
Ying-jie Z., 1174
Yoda K., 1175, 1198
Yokokawa M., 972
Yokota N., 777
Yoon S. C., 881
Yoon S. M., 789, 962
Yorozu A., 721
Yoshida K., 721
Yoshitaka M., 1552
Yu B., 1318
Yu C., 406, 775, 1538
Yu C. X., 1402
Yu Y., 775
Yuen L. K., 1586
Yurut-Caloglu V., 916, 917
Yusuf M. A., 1070
Yutaka M., 1552
Zabel-du Bois A., 1221
Zaccherini I., 587
Zachos G., 822
Zadeh G., 944, 979
Zaffino P., 1276
Zag L., 1570
Zahradnik R., 1411
Zajusz A., 719, 725, 1019
Zamboglou N., 157, 1084
Zanini A., 1409
Zapata-Criado M., 1113
Zapatero A., 1244
Zarandona U., 185
Zarkar A., 1222
Zaránd P., 1476
Zaugg K., 467
Zawadzki P., 1339
Zbären P., 823
Zefkili S., 761, 1317
Zehentmayr F., 981
Zeil K., 563
Zellars R., 750, 767
Zeng G., 1324
Zenone F., 741, 1004
Zepernick P. R., 249
Zerini D., 36, 722, 1012
Zeverino M., 105, 598, 898, 909
Zhan Q., 1324
Zhang G., 758, 983, 1157
Zhang H., 1180
Zhang J., 406
Zhang L., 231
Zhang Y., 1177, 1269
Zheng M., 775
Zholdybay Z., 787
Zhu S., 931, 967
Ziccarelli L., 948
Ziccarelli P., 948
Zietman A., 345
Ziglio F., 716, 1040
Zilli T., 83, 1044, 1074
Zimmermann J., 226
Zimmermann S. J., 1445
Zips D., 273
Zobec Logar H. B., 630, 654, 715
Zogal P., 687
Zografos G., 757
Zoltán N., 1570, 1572
Zonca G., 678, 1262, 1431, 1432
Zotova O., 759
Zourari K., 421, 1087

S 611

AUTHOR INDEX
Zuber M., 1165, 1171
Zucca Aparicio D., 1133, 1347, 1401, 1553
Zucca D., 1239, 1342, 1448
Zucchetti C., 1370
Zuchora A., 700
Zulliger M., 1384
Zuniga A., 452

Zurita Herrera M., 631
Zurl B., 1206, 1209
Zvonarev P., 1284
Zwahlen D., 467
Zwerger A., 1165, 1171
Zwierzchowski G., 351, 626, 734
Zyablitsin A., 1518

Álvarez de Sierra P., 16Öllers M., 232, 268, 391, 533
Özen A., 756, 886, 916, 917, 919
Østergaard K. N., 1077
Ślosarek K., 1360
Štrbac B., 1267