bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐E‐P‐18: Intensity‐Modulated Radiation Therapy for Cervical Esophageal Squamous Cell Carcinoma
Authors: Bai W , Qiao X , Zhou Z , Song Y , Zhang R , Zhen C 
Published: June 2015

Purpose:To retrospectively analyze the outcomes and prognostic factors of cervical esophageal squamous cell carcinoma (SCC) treated with intensity modulated radiation therapy (IMRT).Methods:Thirty‐seven patients with cervical esophageal SCC treated with IMRT were analyzed retrospectively. They received 54–66 Gy in 27–32 fractions. Nineteen patients received concurrent (n=12) or sequential (n=7) platinum‐based two drugs chemoradiotherapy. Overall survival (OS), local control rates (LCR) and prognostic factors were evaluated. Acute toxicities and patterns of first failures were observed.Results:The median follow‐up was 46 months for alive patients. The l‐, 3‐, 4‐ and 5‐year OS of the all patients were 83.8%, 59.1%, 47.5% and 32.6% respectively. The median survival time was 46 months. The l‐, 3‐,4‐ and 5‐year LCR were 82.9%, 63.0%, 54.5% and 54.5%, respectively. Univariate and Multivariate analysis all showed that size of GTV was an independent prognostic factor (p=0.033, p=0.039). There were no patients with Grade 3 acute radiation esophagitis and Grade 2–4 acute pneumonitis. The local failure accounted for 70.0% of all treatment‐related failures.Conclusion:IMRT is safe and effective in the treatment of cervical esophageal squamous cell carcinoma. Size of GTV is an independent prognostic factor. Local failure still remains the main reason of treatment failures.The authors declare no conflicts of interest in preparing this article.
SU‐E‐P‐26: Oncospace: A Shared Radiation Oncology Database System Designed for Personalized Medicine, Decision Support, and Research
Authors: Bowers M , Robertson S , Moore J , Wong J , Phillips M , Hendrickson K , Song W , Kwok P , DeWeese T , McNutt T 
Published: June 2015

Purpose:Advancement in Radiation Oncology (RO) practice develops through evidence based medicine and clinical trial. Knowledge usable for treatment planning, decision support and research is contained in our clinical data, stored in an Oncospace database. This data store and the tools for populating and analyzing it are compatible with standard RO practice and are shared with collaborating institutions. The question is ‐ what protocol for system development and data sharing within an Oncospace Consortium? We focus our example on the technology and data meaning necessary to share across the Consortium.Methods:Oncospace consists of a database schema, planning and outcome data import and web based analysis tools.1) Database: The Consortium implements a federated data store; each member collects and maintains its own data within an Oncospace schema. For privacy, PHI is contained within a single table, accessible to the database owner.2) Import: Spatial dose data from treatment plans (Pinnacle or DICOM) is imported via Oncolink. Treatment outcomes are imported from an OIS (MOSAIQ).3) Analysis: JHU has built a number of webpages to answer analysis questions. Oncospace data can also be analyzed via MATLAB or SAS queries.These materials are available to Consortium members, who contribute enhancements and improvements.Results:1) The Oncospace Consortium now consists of RO centers at JHU, UVA, UW and the University of Toronto. These members have successfully installed and populated Oncospace databases with over 1000 patients collectively.2) Members contributing code and getting updates via SVN repository. Errors are reported and tracked via Redmine. Teleconferences include strategizing design and code reviews.3) Successfully remotely queried federated databases to combine multiple institutions’ DVH data for dose‐toxicity analysis (see below – data combined from JHU and UW Oncospace).Conclusion:RO data sharing can and has been effected according to the Oncospace Consortium model: http://oncospace.radonc.jhmi.edu/.John Wong ‐ SRA from Elekta; Todd McNutt ‐ SRA from Elekta; Michael Bowers ‐ funded by Elekta
SU‐E‐P‐29: Testing Display Monitors for GSDF Compliance ‐ a Practical Approach
Authors: Gauntt D 
Published: June 2015

Purpose:To develop a simple technique for testing display monitors for compliance with the DICOM Grayscale Standard Display Function (GSDF), in accordance with the recommendations of AAPM Task Group 18.Methods:We have developed a spreadsheet that can be used to compare both the luminance response and contrast response of a display to the GSDF, using luminance measurements of the SMPTE test pattern. The contrast response compares the slope of the GSDF j‐index as a function of pixel value to that of the GSDF function, and should lie within the range 0.85 to 1.15.Results:We present the results of measurements both of primary diagnostic displays and of ultrasound and acquisition workstations, all at a tertiary care hospital. The Barco displays in the radiographic reading rooms are GSDF compliant or nearly so, while those in the ultrasound reading rooms and at the acquisition workstations generally show significantly higher contrast at low luminance levels than they would if GSDF compliant, and lower contrast at high luminance levels.Conclusion:The spreadsheet that we developed allows a simple comparison of measured display contrast response to the GSDF. Although we used the SMPTE pattern, the same technique could be used with other grayscale patterns, such as TG18‐QC and TG18‐PQC.
SU‐E‐P‐31: Quantifying the Amount of Missing Tissue in a Digital Breast Tomosynthesis
Authors: Goodenough D , Olafsdottir H , Olafsson I , Fredriksson J , Mallozzi R , Kristinsson S , Healy A , Oskarsdottir G , Kristbjornsson A , Levy J 
Published: June 2015

Purpose:To automatically quantify the amount of missing tissue in a digital breast tomosynthesis system using four stair‐stepped chest wall missing tissue gauges in the Tomophan™ from the Phantom Laboratory and image processing from Image Owl.Methods:The Tomophan™ phantom incorporates four stair‐stepped missing tissue gauges by the chest wall, allowing measurement of missing chest wall in two different locations along the chest wall at two different heights. Each of the four gauges has 12 steps in 0.5 mm increments rising from the chest wall. An image processing algorithm was developed by Image Owl that first finds the two slices containing the steps then finds the signal through the highest step in all four gauges. Using the signal drop at the beginning of each gauge the distance to the end of the image gives the length of the missing tissue gauge in millimeters.Results:The Tomophan™ was imaged in digital breast tomosynthesis (DBT) systems from various vendors resulting in 46 cases used for testing. The results showed that on average 1.9 mm of 6 mm of the gauges are visible. A small focus group was asked to count the number of visible steps for each case which resulted in a good agreement between observer counts and computed data.Conclusion:First, the results indicate that the amount of missing chest wall can differ between vendors. Secondly it was shown that an automated method to estimate the amount of missing chest wall gauges agreed well with observer assessments. This finding indicates that consistency testing may be simplified using the Tomophan™ phantom and analysis by an automated image processing named Tomo QA. In general the reason for missing chest wall may be due to a function of the beam profile at the chest wall as DBT projects through the angular sampling.Research supported by Image Owl, Inc., The Phantom Laboratory, Inc. and Raforninn ehf; Mallozzi and Healy employed by The Phantom Laboratory, Inc.; Goodenough is a consultant to The Phantom Laboratory, Inc.; Fredriksson, Kristbjornsson, Olafsson, Oskarsdottir and Olafsdottir are employed by Raforninn, Ehf
SU‐E‐P‐34: Dose Perturbation Caused by Sun Nuclear QED Diode When Used for Very Small Electron Fields
Authors: Klash S , Steinman J , Stanley T 
Published: June 2015

Purpose:Diodes are utilized by radiotherapy departments to help verify that treatment fields are being delivered correctly to the patient. Some treatment fields utilize electron beams along with a cerrobend cutout to shape the beam to the area to be treated. Cerrobend cutouts can sometimes be very small < 2×2‐cm2. Some published work has addressed diode perturbation for cutout sizes down to 1.5‐cm, this work addresses the diode perturbation of the Sun Nuclear QEDTM diode for cutouts as small as 0.5‐cm in diameter.Methods:Measurements were taken with an A16 Exradin micro‐chamber in Solid Water to 100‐cm SSD. Dmax was determined for each cutout using various amounts of Solid Water in 1–2 mm increments to account for the dmax shifting in small fields. The diode was placed on top of the solid water to 100‐cm SSD in the center of the cutout. Measurements were taken with no diode for comparison. The cutouts ranged in diameter from 0.5‐cm to 5.0‐cm and included the open 6×6 insert. Measurements were made for energies 6, 9, 12, 15,&18 MeV.Results:For 6 MeV, the percent dose reduction from the diode in the cutout field compared to the field without the diode ranged from 35% to 25% as a function of cutout size. For higher energies, this percentage decreased and generally was 25% to 15%. It was observed that dmax shifts significantly upstream for very small cutouts (<2‐cm diameter) to less than 1 cm for all energies.Conclusion:The presence of diodes in small electron fields is enough to cause significant dose perturbation to the target volume. It is recommended that diodes for very small electron fields be used sparingly or possibly with a dose correction per treatment fraction(s), if the total projected delivered dose is going to be significantly different from that prescribed by the physician.
SU‐E‐P‐35: Real‐Time Patient Transit Dose Verification of Volumetric Modulated Arc Radiotherapy by a 2D Ionization Chamber Array
Authors: Liu X 
Published: June 2015

Purpose:To explore the real‐time dose verification method in volumetric modulated arc radiotherapy (VMAT) with a 2D array ion chamber array.Methods:The 2D ion chamber array was fixed on the panel of electronic portal imaging device (EPID). Source‐detector distance (SDD)was 140cm. 8mm RW3 solid water was added to the detector panel to achieve maximum readings.The patient plans for esophageal, prostate and liver cancers were selected to deliver on the cylindrical Cheese phantom 5 times in order to validate the reproducibility of doses. Real‐time patient transit dose measurements were performed at each fraction. Dose distributions wereevaluated using gamma index criteria of 3mm DTA and 3% dose difference referred to the firsttime Result.Results:The gamma index pass rate in the Cheese phantom were about 98%; The gamma index pass rate for esophageal, liver and prostate cancer patient were about 92%,94%, and 92%, respectively; Gamma pass rate for all single fraction were more than 90%.Conclusion:The 2D array is capable of monitoring the real time transit doses during VMAT delivery. It is helpful to improve the treatment accuracy.
SU‐E‐P‐36: Evaluation of MLC Positioning Errors in Dynamic IMRT Treatments by Analyzing Dynalog Files
Authors: Olasolo J , Pellejero S , Gracia M , Gallardo N , Martin M , Lozares S , Maneru F , Bragado L , Miquelez S , Rubio A 
Published: June 2015

Purpose:To assess the accuracy of MLC positioning in Varian linear accelerator, in dynamic IMRT technique, from the analysis of dynalog files generated by the MLC controller.Methods:In Clinac accelerators (pre‐TrueBeam technology), control system has an approximately 50ms delay (one control cycle time). Then, the system compares the measured position to the planned position corresponding to the next control cycle. As it has been confirmed by Varian technical support, this effect causes that measured positions appear in dynalogs one cycle out of phase with respect to the planned positions. Around 9000 dynalogs have been analyzed, coming from the three linear accelerators of our center (one Trilogy and two Clinac 21EX) equipped with a Millennium 120 MLC. In order to compare our results to recent publications, leaf positioning errors (RMS and 95th percentile) are calculated with and without delay effect. Dynalogs have been analyzed using a in‐house Matlab software.Results:The RMS errors were 0.341, 0.339 and 0.348mm for each Linac; being the average error 0.343 mm. The 95th percentiles of the error were 0.617, 0.607 and 0.625; with an average of 0.617mm. A recent multi‐institution study carried out by Kerns et al. found a mean leaf RMS error of 0.32mm and a 95th percentile error value of 0.64mm.Without delay effect, mean leaf RMS errors obtained were 0.040, 0.042 and 0.038mm for each treatment machine; being the average 0.040mm. The 95th percentile error values obtained were 0.057, 0.058 and 0.054 mm, with an average of 0.056mm.Conclusion:Results obtained for the mean leaf RMS error and the mean 95th percentile were consistent with the multi‐institution study. Calculated error statistics with delay effect are significantly larger due to the speed proportional and systematic leaf offset. Consequently it is proposed to correct this effect in dynalogs analysis to determine the MLC performance.
SU‐E‐P‐41: Imaging Coordination of Cone Beam CT, On‐Board Image Conjunction with Optical Image Guidance for SBRT Treatment with Respiratory Motion Management
Authors: Liu Y , Campbell J 
Published: June 2015

Purpose:To spare normal tissue for SBRT lung/liver patients, especially for patients with significant tumor motion, image guided respiratory motion management has been widely implemented in clinical practice. The purpose of this study was to evaluate imaging coordination of cone beam CT, on‐board X‐ray image conjunction with optical image guidance for SBRT treatment with motion management.Methods:Currently in our clinic a Varian Novlis Tx was utilized for treating SBRT patients implementing CBCT. A BrainLAB X‐ray ExacTrac imaging system in conjunction with optical guidance was primarily used for SRS patients. CBCT and X‐ray imaging system were independently calibrated with 1.0 mm tolerance. For SBRT lung/liver patients, the magnitude of tumor motion was measured based‐on 4DCT and the measurement was analyzed to determine if patients would be beneficial with respiratory motion management. For patients eligible for motion management, an additional CT with breath holding would be scanned and used as primary planning CT and as reference images for Cone beam CT. During the SBRT treatment, a CBCT with pause and continuing technology would be performed with patients holding breath, which may require 3–4 partially scanned CBCT to combine as a whole CBCT depending on how long patients capable of holding breath. After patients being setup by CBCT images, the ExactTrac X‐ray imaging system was implemented with patients’ on‐board X‐ray images compared to breath holding CT‐based DRR.Results:For breath holding patients SBRT treatment, after initially localizing patients with CBCT, we then position patients with ExacTrac X‐ray and optical imaging system. The observed deviations of real‐time optical guided position average at 3.0, 2.5 and 1.5 mm in longitudinal, vertical and lateral respectively based on 35 treatments.Conclusion:The respiratory motion management clinical practice improved our physician confidence level to give tighter tumor margin for sparing normal tissue for SBRT lung/liver patients.
SU‐E‐P‐42: Benefit of Equivalent Uniform Dose in Prostate IMRT Planning to Reduce Bladder Toxicity
Authors: Zhu J , Simon A , Haigron P , Lafond C , Acosta O , Shu H , Castelli J , Li B , De Crevoisier R 
Published: June 2015

Purpose:To assess the benefit of bladder wall sub‐volume equivalent uniform dose (EUD) constrains in prostate cancer IMRT planningMethods:The bladder wall was defined by the volume between the external manually delineated wall and a contraction of 7 mm from this external wall. This bladder wall was then separated into two parts: the internal‐bladder wall (bla‐in) represented by the portion of the bladder wall that intersected with the planning target volume (PTV) plus 5 mm extension; the external‐bladder wall (bla‐ex) represented by the remaining part of the bladder wall. Two IMRT plans, with and without using EUD constraints, were generated and compared for 53 prostate cancer patients, to deliver 80Gy to the prostate PTV (V95>95%). In the plan with EUD constraints, the values of the “a” parameter of the EUD models were: 10.0 for bla‐in and 2.3 for bla‐ex., and 5 for the rectum.Results:The use of bladder EUD objectives increased significantly the conformal index (0.73±0.04 vs. 0.93±0.02) and decreased both the doses in the bladder wall (V70: 22.66% vs. 18.88%, Dmean: 39.40Gy vs. 35.04Gy) and the bladder wall NTCP values (NTCP at 3 years bladder toxicity >= LENT/SOMA Grade2: 16.68% vs. 14.48%, NTCP at 3 years bladder bleeding: 7.16% vs. 5.88%, NTCP at 5 years bladder toxicity >= LENT/SOMA Grade2: 20.15% vs. 17.75%, NTCP at 5 years bladder bleeding: 10.38% vs. 8.36%). The use of bladder EUD objectives, although slightly decreasing the dose to the rectum wall (Dmax: 75.19Gy vs. 75.05Gy, V72: 12.95Gy vs. 12.72Gy) as well, increased however the dose in the femoral heads (V55‐femoral head left: 0.06% vs. 0.30%, V55‐femoral head right: 0.04% vs. 0.21%).Conclusion:Separating bladder wall into two parts with appropriate bladder EUD objectives may reduce bladder toxicity, while keeping high dose to the prostate.
SU‐E‐P‐43: A Knowledge Based Approach to Guidelines for Software Safety
Authors: Salomons G , Kelly D 
Published: June 2015

Purpose:In the fall of 2012, a survey was distributed to medical physicists across Canada. The survey asked the respondents to comment on various aspects of software development and use in their clinic. The survey revealed that most centers employ locally produced (in‐house) software of some kind. The respondents also indicated an interest in having software guidelines, but cautioned that the realities of cancer clinics include variations, that preclude a simple solution. Traditional guidelines typically involve periodically repeating a set of prescribed tests with defined tolerance limits. However, applying a similar formula to software is problematic since it assumes that the users have a perfect knowledge of how and when to apply the software and that if the software operates correctly under one set of conditions it will operate correctly under all conditionsMethods:In the approach presented here the personnel involved with the software are included as an integral part of the system. Activities performed to improve the safety of the software are done with both software and people in mind. A learning oriented approach is taken, following the premise that the best approach to safety is increasing the understanding of those associated with the use or development of the software.Results:The software guidance document is organized by areas of knowledge related to use and development of software. The categories include: knowledge of the underlying algorithm and its limitations; knowledge of the operation of the software, such as input values, parameters, error messages, and interpretation of output; and knowledge of the environment for the software including both data and users.Conclusion:We propose a new approach to developing guidelines which is based on acquiring knowledge‐rather than performing tests. The ultimate goal is to provide robust software guidelines which will be practical and effective.
SU‐E‐P‐48: Evaluation of Intensity Modulated Radiotherapy (IMRT) with Three Different Commercial Planning Systems for the Treatment of Cervical Cancer
Authors: Liu D , Chi Z , Yang H , Miao M , Jing Z 
Published: June 2015

Purpose:To investigate the performances of three commercial treatment planning systems (TPS) for intensity modulated radiotherapy (IMRT) optimization regarding cervical cancer.Methods:For twenty cervical cancer patients, three IMRT plans were retrospectively re‐planned: one with Pinnacle TPS,one with Oncentra TPS and on with Eclipse TPS. The total prescribed dose was 50.4 Gy delivered for PTV and 58.8 Gy for PTVnd by simultaneous integrated boost technique. The treatments were delivered using the Varian 23EX accelerator. All optimization schemes generated clinically acceptable plans. They were evaluated based on target coverage, homogeneity (HI) and conformity (CI). The organs at risk (OARs) were analyzed according to the percent volume under some doses and the maximum doses. The statistical method of the collected data of variance analysis was used to compare the difference among the quality of plans.Results:IMRT with Eclipse provided significant better HI, CI and all the parameters of PTV. However, the trend was not extension to the PTVnd, it was still significant better at mean dose, D50% and D98%, but plans with Oncentra showed significant better in the hight dosage volume, such as maximum dose and D2%. For the bladder wall, there were not notable difference among three groups, although Pinnacle and Oncentra systems provided a little lower dose sparing at V50Gy of bladder and rectal wall and V40Gy of bladder wall, respectively. V40Gy of rectal wall (p=0.037), small intestine (p=0.001 for V30Gy, p=0.010 for maximum dose) and V50Gy of right‐femoral head (p=0.019) from Eclipse plans showed significant better than other groups.Conclusion:All SIB‐IMRT plans were clinically acceptable which were generated by three commercial TPSs. The plans with Eclipse system showed advantages over the plans with Oncentra and Pinnacle system in the overwhelming majority of the dose coverage for targets and dose sparing of OARs in cervical cancer.
SU‐E‐P‐49: Evaluation of Image Quality and Radiation Dose of Various Unenhanced Head CT Protocols
Authors: Chen L , Khan M , Alapati K , Hsieh M , Barry K 
Published: June 2015

Purpose:To evaluate the diagnostic value of various unenhanced head CT protocols and predicate acceptable radiation dose level for head CT exam.Methods:Our retrospective analysis included 3 groups, 20 patients per group, who underwent clinical routine unenhanced adult head CT examination. All exams were performed axially with 120 kVp. Three protocols, 380 mAs without iterative reconstruction and automAs, 340 mAs with iterative reconstruction without automAs, 340 mAs with iterative reconstruction and automAs, were applied on each group patients respectively. The images were reconstructed with H30, J30 for brain window and H60, J70 for bone window. Images acquired with three protocols were randomized and blindly reviewed by three radiologists. A 5 point scale was used to rate each exam The percentage of exam score above 3 and average scores of each protocol were calculated for each reviewer and tissue types.Results:For protocols without automAs, the average scores of bone window with iterative reconstruction were higher than those without iterative reconstruction for each reviewer although the radiation dose was 10 percentage lower. 100 percentage exams were scored 3 or higher and the average scores were above 4 for both brain and bone reconstructions. The CTDIvols are 64.4 and 57.8 mGy of 380 and 340 mAs, respectively. With automAs, the radiation dose varied with head size, resulting in 47.5 mGy average CTDIvol between 39.5 and 56.5 mGy. 93 and 98 percentage exams were scored great than 3 for brain and bone windows, respectively. The diagnostic confidence level and image quality of exams with AutomAs were less than those without AutomAs for each reviewer.Conclusion:According to these results, the mAs was reduced to 300 with automAs OFF for head CT exam. The radiation dose was 20 percentage lower than the original protocol and the CTDIvol was reduced to 51.2 mGy.