bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐G‐304‐02: Physics of the AAPM
Authors: Keener J. 
Published: June 2015

As a new member of AAPM, it's easy to feel overwhelmed by the size and complexity of the association and to be unaware of the benefits and opportunities available to members. At this year's AAPM Annual Meeting in Anaheim, we will host a New Member Symposium where you can learn more about the organization, member resources, opportunities to get involved, and about topics of particular interest to new professionals. We encourage you to take advantage of this great opportunity to learn valuable information and to grow your professional network.Following an introduction from Dr. John Boone, AAPM President; Justin Keener, Chair of the New Professional Subcommittee, will speak on, “Physics of the AAPM.” Next will be Dr. George Sherouse sharing invaluable information in his talk, “Things You Won't Be Able to Say Somebody Should've Told You.”Registered attendees will receive a raffle ticket. Enter to win a complimentary registration for the 2016 Annual Meeting in Washington, DC!In addition, all new members who register for the Symposium will receive a drink ticket, good for one complimentary soda or beer served after the New Member Symposium during the social with Committee Chairs from 4 AAPM Councils: Science, Education, Professional and Administrative.Get your picture taken!!! There will be a photographer there to take pictures for your profile in the AAPM directory.The New Member Symposium is a (free) ticket option when you register online for the Annual Meeting. We hope that you will plan to attend.
TU‐F‐201‐00: Radiochromic Film Dosimetry Update
Authors: Chiu‐Tsao Sou‐Tung 
Published: June 2015

Since the introduction of radiochromic films (RCF) for radiation dosimetry, the scope of RCF dosimetry has expanded steadily to include many medical applications, such as radiation therapy and diagnostic radiology. The AAPM Task Group (TG) 55 published a report on the recommendations for RCF dosimetry in 1998. As the technology is advancing rapidly, and its routine clinical use is expanding, TG 235 has been formed to provide an update to TG‐55 on radiochromic film dosimetry. RCF dosimetry applications in clinical radiotherapy have become even more widespread, expanding from primarily brachytherapy and radiosurgery applications, and gravitating towards (but not limited to) external beam therapy (photon, electron and protons), such as quality assurance for IMRT, VMAT, Tomotherapy, SRS/SRT, and SBRT. In addition, RCF applications now extend to measurements of radiation dose in particle beams and patients undergoing medical exams, especially fluoroscopically guided interventional procedures and CT. The densitometers/scanners used for RCF dosimetry have also evolved from the He‐Ne laser scanner to CCD‐based scanners, including roller‐based scanner, light box‐based digital camera, and flatbed color scanner. More recently, multichannel RCF dosimetry introduced a new paradigm for external beam dose QA for its high accuracy and efficiency. This course covers in detail the recent advancements in RCF dosimetry.Learning Objectives:

Introduce the paradigm shift on multichannel film dosimetry
Outline the procedures to achieve accurate dosimetry with a RCF dosimetry system
Provide comprehensive guidelines on RCF dosimetry for various clinical applications
One of the speakers has a research agreement from Ashland Inc., the manufacturer of Gafchromic film.
TU‐G‐213‐03: IEC Subcommittee 62C (Equipment for Radiotherapy, Nuclear Medicine and Radiation Dosimetry): Recent and Active Projects
Authors: Culberson W. 
Published: June 2015

The International Electrotechnical Commission (IEC) writes standards that manufacturers of electrical equipment must comply with. Medical electrical equipment, such as medical imaging, radiation therapy, and radiation dosimetry devices, fall under Technical Committee 62. Of particular interest to medical physicists are the standards developed within Subcommittees (SC) 62B, which addresses diagnostic radiological imaging equipment, and 62C, which addresses equipment for radiation therapy, nuclear medicine and dosimetry. For example, a Working Group of SC 62B is responsible for safety and quality assurance standards for CT scanners and a Working Group of SC 62C is responsible for standards that set requirements for dosimetric safety and accuracy of linacs and proton accelerators. IEC standards thus have an impact on every aspect of a medical physicist's job, including equipment testing, shielding design, room layout, and workflow. Consequently, it is imperative that US medical physicists know about existing standards, as well as have input on those under development or undergoing revision.The structure of the IEC and current standards development work will be described in detail. The presentation will explain how US medical physicists can learn about IEC standards and contribute to their development.Learning Objectives:

Learn about the structure of the IEC and the influence that IEC standards have on the design of equipment for radiology and radiation therapy.
Learn about the mechanisms by which the US participates in the development and revision of standards.
Understand the specific requirements of several standards having direct relevance to diagnostic and radiation therapy physicists.
TU‐G‐BRD‐04: A Round Robin Dosimetry Intercomparison of Gamma Stereotactic Radiosurgery Calibration Protocols
Authors: Drzymala R , Alvarez P , Bednarz G , Bourland J , DeWerd L , Ma L , Meltsner S , Neyman G , Novotny J , Petti P , Rivard M , Shiu A , Goetsch S 
Published: June 2015

Purpose:The purpose of this multi‐institutional study was to compare two new gamma stereotactic radiosurgery (GSRS) dosimetry protocols to existing calibration methods. The ultimate goal was to guide AAPM Task Group 178 in recommending a standard GSRS dosimetry protocol.Methods:Nine centers (ten GSRS units) participated in the study. Each institution made eight sets of dose rate measurements: six with two different ionization chambers in three different 160mm‐diameter spherical phantoms (ABS plastic, Solid Water and liquid water), and two using the same ionization chambers with a custom in‐air positioning jig. Absolute dose rates were calculated using a newly proposed formalism by the IAEA working group for small and non‐standard radiation fields and with a new air‐kerma based protocol. The new IAEA protocol requires an in‐water ionization chamber calibration and uses previously reported Monte‐Carlo generated factors to account for the material composition of the phantom, the type of ionization chamber, and the unique GSRS beam configuration. Results obtained with the new dose calibration protocols were compared to dose rates determined by the AAPM TG‐21 and TG‐51 protocols, with TG‐21 considered as the standard.Results:Averaged over all institutions, ionization chambers and phantoms, the mean dose rate determined with the new IAEA protocol relative to that determined with TG‐21 in the ABS phantom was 1.000 with a standard deviation of 0.008. For TG‐51, the average ratio was 0.991 with a standard deviation of 0.013, and for the new in‐air formalism it was 1.008 with a standard deviation of 0.012.Conclusion:Average results with both of the new protocols agreed with TG‐21 to within one standard deviation. TG‐51, which does not take into account the unique GSRS beam configuration or phantom material, was not expected to perform as well as the new protocols. The new IAEA protocol showed remarkably good agreement with TG‐21.Conflict of Interests: Paula Petti, Josef Novotny, Gennady Neyman and Steve Goetsch are consultants for Elekta Instrument A/B; Elekta Instrument AB, PTW Freiburg GmbH, Standard Imaging, Inc., and The Phantom Laboratory, Inc. loaned equipment for use in these experiments; The University of Wisconsin Accredited Dosimetry Calibration Laboratory provided calibration services.
TU‐G‐BRD‐05: Results From Multi‐Institutional Measurements with An Anthropomorphic Spine Phantom
Authors: Molineu A , Hernandez N , Alvarez P , Followill D 
Published: June 2015

Purpose:To analyze the results from an anthropomorphic spine phantom used for credentialing institutions for National Cancer Institute (NCI) sponsored clinical trial.Methods:An anthropomorphic phantom that contains left and right lungs, a heart, an esophagus, spinal cord, bony material and a PTV was sent to institutions wishing to be credentialed for NCI trials. The PTV holds 4 TLD and radiochromic film in the axial and sagittal planes. The heart holds one TLD. Institutions created IMRT plans to cover ≥90% of the PTV with 6 Gy and limit the cord dose to <0.35cc receiving 3.75 Gy and <1.2cc receiving 2.63 Gy. They were instructed to treat the phantom as they would a patient, including making plan specific IMRT/SBRT QA measurements before treatment. The TLD results in the PTV were required to be within ±7% of the plan dose. A gamma calculation was performed using the film results and the submitted DICOM plan. ≥85% of the analyzed region was required to pass a 5%/3 mm criteria.Results:176 institutions irradiated the spine phantom for a total of 255 results. The pass rate was 73% (187 irradiations) overall. 44 irradiations failed only the gamma criteria, 2 failed only the dose criteria and 22 failed both. The most used planning systems were Eclipse (116) and Pinnacle (52) and they had pass rates of 76% and 71%, respectively. The AAA algorithm had a pass rate of 77% while superposition type algorithms had a 71% pass rate. The average TLD measurement to institution calculation ratio was 0.99 (0.04 std dev.). The average percent pixels passing the gamma criteria for films was 89% (12% std dev.)Conclusion:Results show that this phantom is an important part of credentialing and that we have room for improvement in IMRT/SBRT spine treatments.This work was supported by PHS CA180803 and CA037422 awarded by NCI, DHHS.
TU‐G‐BRD‐09: Evaluation of Patient DVH‐Based QA Metrics for Prostate VMAT: Correlation Between Accuracy of Estimated 3D Patient Dose and MLC Position Error
Authors: Kadoya N , Saito M , Fujita Y , Ogasawara M , Ito K , Sato K , Kishi K , Dobashi S , Takeda K , Jingu K 
Published: June 2015

Purpose:The purpose of this study was to evaluate the accuracy of patient DVH‐based QA metrics and test the hypothesis: measurement‐guided 3D dose reconstruction (MGDR) captures the induced dose error.Methods:We used 3DVH software with an ArcCHECK to estimate 3D patient dose by MGDR. Two different calculating modes of MGDR were used: “Normal Sensitivity” and “High Sensitivity”. Ten prostate cancer patients treated with hypo‐fractionated VMAT (67.6 Gy/26 Fr) were studied. For the baseline plan, we induced MLC errors (−0.75, −0.5, −0.25, 0.25, 0.5 and 0.75 mm for each single bank), generated by in‐house software. We compared the 3D patient dose estimated by 3DVH and that calculated by the treatment planning system. We evaluated the correlation between dose estimation error and MLC position error.Results:Slopes of linear fit to dose estimation error versus MLC position error for mean dose and D95 to the PTV were 1.76 and 1.40% mm‐1, respectively, for “Normal Sensitivity” and −0.53 and −0.88% mm‐1, respectively, for “High Sensitivity”, showing better accuracy for “High Sensitivity” than “Normal Sensitivity”. On the other hand, the slopes for mean dose to the rectum and bladder and V55 to the rectum and bladder were −1.00, −0.55, −3.53 and −1.85% mm‐1, respectively, for “Normal Sensitivity” and −2.89, −2.39, −6.24 and −4.11% mm‐1, respectively, for “High Sensitivity”, showing significant better accuracy for “Normal Sensitivity” than “High Sensitivity”.Conclusion:Our results showed that 3DVH had some residual error for both sensitivities, indicating the MGDR could capture a part of the induced error but not all of the induced error.Furthermore, we found that “Normal Sensitivity” might have better accuracy for the DVH metric for PTV and that “High Sensitivity” might have better accuracy for DVH metrics for the rectum and bladder. We must be willing to tolerate this residual error in clinical care.
TU‐G‐BRB‐00: Clinical Trials in Proton and Particle Therapy
Authors: Schulte Reinhard 
Published: June 2015

Proton therapy, in particular, and ion therapy, just beginning, are becoming an increasing focus of attention in clinical radiation oncology and medical physics. Both modalities have been criticized of lacking convincing evidence from randomized trials proving their efficacy, justifying the higher costs involved in these therapies.This session will provide an overview of the current status of clinical trials in proton therapy, including recent developments in ion therapy. As alluded to in the introductory talk by Dr. Schulte, opinions are diverging widely as to the usefulness and need for clinical trials in particle therapy and the challenge of equipoise. The lectures will highlight some of the challenges that surround clinical trials in particle therapy. One, presented by Dr. Choy from UT Southwestern, is that new technology and even different types of particles such as helium and carbon ions are introduced into this environment, increasing the phase space of clinical variables. The other is the issue of medical physics quality assurance with physical phantoms, presented by Mrs. Taylor from IROC Houston, which is more challenging because 3D and 4D image guidance and active delivery techniques are in relatively early stages of development. The role of digital phantoms in developing clinical treatment planning protocols and as a QA tool will also be highlighted by Dr. Lee from NCI.The symposium will be rounded off by a panel discussion among the Symposium speakers, arguing pro or con the need and readiness for clinical trials in proton and ion therapy.Learning Objectives:

To get an update on the current status of clinical trials allowing or mandating proton therapy.
Learn about the status of planned clinical trials in the U.S. and worldwide involving ion therapy.
Discuss the challenges in the design and QA of clinical trials in particle therapy.
Learn about existing and future physical and computational anthropomorphic phantoms for charged particle clinical trial development and support.
Research reported in this presentation is supported by the National Cancer Institute of the National; Institutes of Health under Award Number P20CA183640.
TU‐G‐BRA‐04: Changes in Regional Lung Function Measured by 4D‐CT Ventilation Imaging for Thoracic Radiotherapy
Authors: Nakajima Y , Kadoya N , Kabus S , Loo B , Keall P , Yamamoto T 
Published: June 2015

Purpose:To test the hypothesis: 4D‐CT ventilation imaging can show the known effects of radiotherapy on lung function: (1) radiation‐induced ventilation reductions, and (2) ventilation increases caused by tumor regression.Methods:Repeat 4D‐CT scans (pre‐, mid‐ and/or post‐treatment) were acquired prospectively for 11 thoracic cancer patients in an IRB‐approved clinical trial. A ventilation image for each time point was created using deformable image registration and the Hounsfield unit (HU)‐based or Jacobian‐based metric. The 11 patients were divided into two subgroups based on tumor volume reduction using a threshold of 5 cm3. To quantify radiation‐induced ventilation reduction, six patients who showed a small tumor volume reduction (<5 cm3) were analyzed for dose‐response relationships. To investigate ventilation increase caused by tumor regression, two of the other five patients were analyzed to compare ventilation changes in the lung lobes affected and unaffected by the tumor. The remaining three patients were excluded because there were no unaffected lobes.Results:Dose‐dependent reductions of HU‐based ventilation were observed in a majority of the patient‐specific dose‐response curves and in the population‐based dose‐response curve, whereas no clear relationship was seen for Jacobian‐based ventilation. The post‐treatment population‐based dose‐response curve of HU‐based ventilation demonstrated the average ventilation reductions of 20.9±7.0% at 35–40 Gy (equivalent dose in 2‐Gy fractions, EQD2), and 40.6±22.9% at 75–80 Gy EQD2. Remarkable ventilation increases in the affected lobes were observed for the two patients who showed an average tumor volume reduction of 37.1 cm3 and re‐opening airways. The mid‐treatment increase in HU‐based ventilation of patient 3 was 100.4% in the affected lobes, which was considerably greater than 7.8% in the unaffected lobes.Conclusion:This study has demonstrated that 4D‐CT ventilation imaging shows the known effects of radiotherapy on lung function: radiation‐induced ventilation reduction and ventilation increase caused by tumor regression, providing validation for 4D‐CT ventilation imaging.This study was supported in part by a National Lung Cancer Partnership Young Investigator Research grant.
TU‐G‐BRA‐06: PET‐Based Treatment Response Assessement for Neoadjuvent Chemoradiation for Pancreatic Adenocarcinoma
Authors: Dalah E , Tai A , Oshima K , Hall W , Erickson B , Li X 
Published: June 2015

Purpose:To address the limitations of the conventional response evaluation criteria in solid tumors (RECIST), and validate PET response criteria in solid tumors (PERCIST1.0). We analyze the relationship between the pathological treatment response (PTR) and PERCIST1.0 for patients treated with neoadjuvent chemoradiation (nCR) for pancreatic adenocarcinoma.Methods:The pre‐ and post‐nCR CT and PET data for a total of 8 patients with resectable, or borderline resectable pancreatic head adenocarcinoma treated with nCR were retrospectively analyzed. These data were compared with the PTR which were graded according to tumor cell destruction (cellularity), with Grade1, 2 or 3 (G1, G2 or G3) for good, moderate, and poor responses, respectively. RECIST‐based PET (RECISTPET), and PERCIST1.0 were defined using lean body mass normalized SUV (nSUVlb). RECIST‐based CT (RECISTCT) was defined by contouring the whole pancreas head (CTPH). Pre‐ and post‐nSUVlb and SUVbw, PERCIST 1.0, were correlated with PTR using Pearson's correlation coefficient test.Results:The average mean and SD in nSUVlb for all 8 patients analyzed were lower in post‐nCR (1.35±0.34) compared to those at pre‐nCR (1.38±0.20). Using PERCIST1.0, 5/8 patients showed stable metabolic disease (SMD), 2/8 partial metabolic response (PMR), and 1/8 progressive metabolic disease (PMD). Using RECISTPET 4/8 showed stable disease (STD), 4/8 partial response (PR), whereas 8/8 showed stable disease (STD) using RECISTCT. PTR were correlated with PERCIST1.0 (R=0.3780/P=0.6071). Pathological tumor size was correlated with RECISTCT (R=0.0727/P=0.8679), and RECISTPET, R=−0.3333/P=0.3798.Conclusion:Chemoradiation treatment response assessment based on metabolic tumor activities using PRECIST1.0 and RECISTPET appears to provide better agreement with pathological assessment as compared to the conventional CT‐based assessment using RECISTCT. The integration of these additional radiographic metrics in assessing treatment response to nCR for pancreatic adenocarcinoma may provide a promising strategy to better select those patients most suitable for therapeutic intensification.
TU‐G‐BRA‐09: MR Elastography as a Predictor of Therapeutic Response: Assessment in Non‐Hodgkin's Lymphoma (NHL)
Authors: Pepin K , Ansell S , Ehman R , McGee K 
Published: June 2015

Purpose:To develop magnetic resonance elastography (MRE) as a noninvasive imaging biomarker of treatment response in cancer and to evaluate its prognostic potential for assessing chemotherapy response in non‐Hodgkin's lymphoma (NHL).Methods:A small animal cancer MRE methodology was developed which included a custom‐built 4 cm, 8‐channel receive‐only coil and an electromechanical driver capable of producing shear waves at a frequency of 800 Hz attached to an MRI‐compatible needle inserted in tissue. MRE reproducibility was evaluated in tumor phantoms and in vivo mouse experiments. Tumor shear stiffness was monitored following a single chemotherapy treatment in a murine xenograft of NHL to determine the biomechanical effect of an initial therapy response followed by tumor regrowth. The effect of an increased chemotherapy dose on the resulting decrease in tumor shear stiffness was quantified. In vivo evaluation of the feasibility of this potential biomarker was performed on three patients with NHL prior to and 2 weeks after chemotherapy treatment.Results:Tumor phantom models and in vivo measurements demonstrated excellent shear stiffness reproducibility with a standard deviation of ±3%. In the murine model, tumor shear stiffness and volume changes following chemotherapy treatment corresponded to periods of response and subsequent tumor regrowth. Shear stiffness alterations demonstrated a dose dependency with a decrease of 15% and 25% for the low and high dose group respectively compared to an increase of 7% in an untreated control group. In three patients with NHL, tumor shear stiffness decreased by an average of 38% within 2 weeks of chemotherapy treatment.Conclusion:These data demonstrate that MRE is a potentially sensitive biomarker of disease stage and response to therapy in cancer. The results demonstrate that MRE‐derived shear stiffness measurements are sensitive to chemotherapy response and disease progression in vivo, and are the first human application of MRE as a noninvasive assessment of therapy response.Funding provided by the Mayo Clinic Center for Individualized Medicine, Imaging Biomarker Discovery Program and the Mayo Graduate School.
TU‐G‐303‐02: Robust Radiomics Methods for PET and CT Imaging
Authors: Aerts H. 
Published: June 2015

‘Radiomics’ refers to studies that extract a large amount of quantitative information from medical imaging studies as a basis for characterizing a specific aspect of patient health. Radiomics models can be built to address a wide range of outcome predictions, clinical decisions, basic cancer biology, etc. For example, radiomics models can be built to predict the aggressiveness of an imaged cancer, cancer gene expression characteristics (radiogenomics), radiation therapy treatment response, etc. Technically, radiomics brings together quantitative imaging, computer vision/image processing, and machine learning. In this symposium, speakers will discuss approaches to radiomics investigations, including: longitudinal radiomics, radiomics combined with other biomarkers (‘pan‐omics’), radiomics for various imaging modalities (CT, MRI, and PET), and the use of registered multi‐modality imaging datasets as a basis for radiomics. There are many challenges to the eventual use of radiomics‐derived methods in clinical practice, including: standardization and robustness of selected metrics, accruing the data required, building and validating the resulting models, registering longitudinal data that often involve significant patient changes, reliable automated cancer segmentation tools, etc. Despite the hurdles, results achieved so far indicate the tremendous potential of this general approach to quantifying and using data from medical images. Specific applications of radiomics to be presented in this symposium will include: the longitudinal analysis of patients with low‐grade gliomas; automatic detection and assessment of patients with metastatic bone lesions; image‐based monitoring of patients with growing lymph nodes; predicting radiotherapy outcomes using multi‐modality radiomics; and studies relating radiomics with genomics in lung cancer and glioblastoma.Learning Objectives:

Understanding the basic image features that are often used in radiomic models.
Understanding requirements for reliable radiomic models, including robustness of metrics, adequate predictive accuracy, and generalizability.
Understanding the methodology behind radiomic‐genomic (‘radiogenomics’) correlations.
Research supported by NIH (US), CIHR (Canada), and NSERC (Canada)