bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐D‐209‐07: Monte Carlo Assessment of Dose to the Lens of the Eye of Radiologist Using Realistic Phantoms and Eyeglass Models
Authors: Xu X , Lin H , Gao Y , Caracappa P , Wang Y , Huo W , Pi Y , Feng M , Chen Z , Dauer L , Thornton R , Dauer Z , Alvarado K , St. Germain J , Solomon S 
Published: July 2016

Purpose:To study how eyeglass design features and postures of the interventional radiologist affect the radiation dose to the lens of the eye.Methods:A mesh‐based deformable phantom, consisting of an ultra‐fine eye model, was used to simulate postures of a radiologist in fluoroscopically guided interventional procedure (facing the patient, 45 degree to the left, and 45 degree to the right). Various eyewear design features were studied, including the shape, lead‐equivalent thickness, and separation from the face. The MCNPX Monte Carlo code was used to simulate the X‐ray source used for the transcatheter arterial chemoembolization procedure (The X‐ray tube is located 35 cm from the ground, emitting X‐rays toward to the ceiling; Field size is 40cm X 40cm; X‐ray tube voltage is 90 kVp). Experiments were also performed using dosimeter placed on a physical phantom behind eyeglasses.Results:Without protective eyewear, the radiologist's eye lens can receive an annual dose equivalent of about 80 mSv. When wearing a pair of lead eyeglasses with lead‐equivalent of 0.5‐mm Pb, the annual dose equivalent of the eye lens is reduced to 31.47 mSv, but both exceed the new ICRP limit of 20 mSv. A face shield with a lead‐equivalent of 0.125‐mm Pb in the shape of a semi‐cylinder (13cm in radius and 20‐cm in height) would further reduce the exposure to the lens of the eye. Examination of postures and eyeglass features reveal surprising information, including that the glass‐to‐eye separation also plays an important role in the dose to the eye lens from scattered X‐ray from underneath and the side. Results are in general agreement with measurements.Conclusion:There is an urgent need to further understand the relationship between the radiation environment and the radiologist's eyewear and posture in order to provide necessary protection to the interventional radiologists under newly reduced dose limits.
TU‐D‐207B‐01: A Prediction Model for Distinguishing Radiation Necrosis From Tumor Progression After Gamma Knife Radiosurgery Based On Radiomics Features From MR Images
Authors: Zhang Z , Ho A , Wang X , Brown P , Guha‐Thakurta N , Ferguson S , Fave X , Zhang L , Mackin D , Court L , Li J , Yang J 
Published: July 2016

Purpose:To develop and validate a prediction model using radiomics features extracted from MR images to distinguish radiation necrosis from tumor progression for brain metastases treated with Gamma knife radiosurgery.Methods:The images used to develop the model were T1 post‐contrast MR scans from 71 patients who had had pathologic confirmation of necrosis or progression; 1 lesion was identified per patient (17 necrosis and 54 progression). Radiomics features were extracted from 2 images at 2 time points per patient, both obtained prior to resection. Each lesion was manually contoured on each image, and 282 radiomics features were calculated for each lesion. The correlation for each radiomics feature between two time points was calculated within each group to identify a subset of features with distinct values between two groups. The delta of this subset of radiomics features, characterizing changes from the earlier time to the later one, was included as a covariate to build a prediction model using support vector machines with a cubic polynomial kernel function. The model was evaluated with a 10‐fold cross‐validation.Results:Forty radiomics features were selected based on consistent correlation values of approximately 0 for the necrosis group and >0.2 for the progression group. In performing the 10‐fold cross‐validation, we narrowed this number down to 11 delta radiomics features for the model. This 11‐delta‐feature model showed an overall prediction accuracy of 83.1%, with a true positive rate of 58.8% in predicting necrosis and 90.7% for predicting tumor progression. The area under the curve for the prediction model was 0.79.Conclusion:These delta radiomics features extracted from MR scans showed potential for distinguishing radiation necrosis from tumor progression. This tool may be a useful, noninvasive means of determining the status of an enlarging lesion after radiosurgery, aiding decision‐making regarding surgical resection versus conservative medical management.
TU‐D‐207B‐03: Early Assessment of Response to Chemoradiotherapy Based On Textural Analysis of Pre and Mid‐Treatment FDG‐PET Image in Locally Advanced Head and Neck Cancer
Authors: Cui Y , Pollom E , Loo B , Le Q , Hara W , Li R 
Published: July 2016

Purpose:To evaluate whether tumor textural features extracted from both pre‐ and mid‐treatment FDG‐PET images predict early response to chemoradiotherapy in locally advanced head and neck cancer, and investigate whether they provide complementary value to conventional volume‐based measurements.Methods:Ninety‐four patients with locally advanced head and neck cancers were retrospectively studied. All patients received definitive chemoradiotherapy and underwent FDG‐PET planning scans both before and during treatment. Within the primary tumor we extracted 6 textural features based on gray‐level co‐occurrence matrices (GLCM): entropy, dissimilarity, contrast, correlation, energy, and homogeneity. These image features were evaluated for their predictive power of treatment response to chemoradiotherapy in terms of local recurrence free survival (LRFS) and progression free survival (PFS). Logrank test were used to assess the statistical significance of the stratification between low‐ and high‐risk groups. P‐values were adjusted for multiple comparisons by the false discovery rate (FDR) method.Results:All six textural features extracted from pre‐treatment PET images significantly differentiated low‐ and high‐risk patient groups for LRFS (P=0.011–0.038) and PFS (P=0.029–0.034). On the other hand, none of the textural features on mid‐treatment PET images was statistically significant in stratifying LRFS (P=0.212–0.445) or PFS (P=0.168–0.299). An imaging signature that combines textural feature (GLCM homogeneity) and metabolic tumor volume showed an improved performance for predicting LRFS (hazard ratio: 22.8, P<0.0001) and PFS (hazard ratio: 13.9, P=0.0005) in leave‐one‐out cross validation. Intra‐tumor heterogeneity measured by textural features was significantly lower in mid‐treatment PET images than in pre‐treatment PET images (T‐test: P<1.4e‐6).Conclusion:Tumor textural features on pretreatment FDG‐PET images are predictive for response to chemoradiotherapy in locally advanced head and neck cancer. The complementary information offered by textural features improves patient stratification and may potentially aid in personalized risk‐adaptive therapy.
TU‐FG‐204‐02: An Overview of the CT Protocol Optimization Team at Johns Hopkins
Authors: Mahesh M. 
Published: July 2016

The role of a medical physicist involved with clinical CT activities is changing rapidly. No longer is the physicist responsible for simply ensuring scanner QA. This shift is evident by looking at the trend to regulate more and more aspects of what activities must be performed to keep a CT practice within compliance. In this symposium, new guidelines from the ACR, Joint Commission, and several states will be addressed. An overview of these regulations will be provided. Then, three speakers will provide an in‐depth account of how their CT protocol Optimization team functions. Lastly, a representative from the Joint Commission will provide recent surveyor education, experience, and trend information.

Learning Objectives:
Understand the ACR, Joint Commission, and aspects of several state regulations/guidelines related to the clinical practice of CT.
Learn how a CT protocol optimization is organized and what tasks physicists perform from the perspective of four different institutions.T. Szczykutowicz, TPS provides CT protocols to GE Healthcare under a license agreement. TPS receives grant support from GE Healthcare.
TU‐FG‐207B‐01: Report On Development of a Database of NIH Funding of Medical Physicists
Authors: Whelan B. 
Published: July 2016

Up‐to‐date knowledge about federal funding opportunities related to medical physics research, as well as obtaining skills for writing effective grant proposals are critical for academic and entrepreneurial medical physicists. In this symposium, program directors from key federal research funding agencies, including the National Cancer Institute, the National Institute of Biomedical Imaging and Bioengineering, and the National Science Foundation, will present information about current funding opportunities relevant to the field of medical physics. They will also provide insight to issues that applicants should pay special attention to when crafting their research grant proposals. In addition, the symposium will include presentations on research funding for small business concerns, and the results of an independent AAPM study of the National Institutes of Health funding of AAPM members from 2002–2015.

Learning Objectives:
To learn about current federal funding initiatives relevant to medical physics research
To learn about tactics important for crafting convincing research proposals
To learn about an independent study of NIH funding of research done by AAPM membersB. Whelan, this work was commissioned and funded by the AAPM
TU‐H‐201‐05: Panel Discussion Member
Authors: Fraass B. 
Published: July 2016

The New New Symposium is a symposium for members relatively new to the organization to learn about the organizational structure and operational procedures of the society; how decisions are made, how the council and committee leadership is appointed and operates, opportunities for volunteer involvement, and a brief overview of the services and efforts provided by the HQ staff and the website. Attendees will hear from council chairs, key staff and chairs, and members with volunteer experience.After the symposium a social hour ensues with opportunities to interact with key AAPM members. The New Member Symposium is a (free) ticket option when you register online for the Annual Meeting. And don't forget registrants receive one (free) ticket for a beverage of your choice during the social afterwards.
TU‐H‐BRC‐04: Feasibility of Using TomoDirect for Pulsed Reduced Dose‐Rate Radiotherapy
Authors: Geurts M 
Published: July 2016

Purpose:Pulsed reduced dose‐rate radiotherapy (PRDR) is a technique used for treatment of recurrent disease where a planned treatment is split into 0.2 Gy pulses, each separated by three‐minute intervals, to achieve a time averaged dose rate of 0.0667 Gy/min. This study investigated the feasibility of using TomoTherapy's fixed angle delivery feature (TomoDirect) to create high quality IMRT plans that meet the radiobiological constraints of PRDR.Methods:Two plans (one craniospinal irradiation and a complex shaped temporal lobe re‐irradiation) were created using a conventional technique and then TomoDirect. Plan quality was compared between techniques. Next, the dose rate to each voxel in the target was computed for each TomoDirect beam to verify that the time‐averaged dose rate is less than 0.0667 Gy/min.Results:The TomoDirect CSI plan provided improved target coverage and organ at risk sparing with a per‐beam treatment time ranging from 21.6 to 43.5 seconds and mean time‐averaged dose rate of 0.032 Gy/min. The TomoDirect temporal lobe plan showed equivalent plan quality to a non‐PRDR TomoHelical IMRT plan with per‐beam treatment times ranging from 43.7 to 44.9 seconds and a mean time‐averaged dose rate of 0.052 Gy/min.Conclusion:Our initial investigation suggests that TomoDirect PRDR is not only feasible but ideal for delivering superior conformality and target homogeneity to complex and large fields.
TU‐H‐BRC‐09: Validation of a Novel Therapeutic X‐Ray Array Source and Collimation System
Authors: Trovati S , Borchard P , King GJ , Limborg CG , Loo BW , Maxim P , McCormick D , Nicolas LY , Schueler E , Tantawi S , Wang J , Wang L 
Published: July 2016

Purpose:We have experimentally characterized and simulated the dosimetric properties and spatial fidelity of a novel X‐ray array source and collimation system called SPHINX that has the potential to generate complex intensity modulated X‐ray beams by varying the electron beam intensity only, and without any moving parts like in multi‐leaf collimators.Methods:We investigated the spatial fidelity and the X‐ray performances of a SPHINX prototype in tungsten, using a Cyber Knife and the experimental high‐energy electron beam line at XTA at SLAC National Laboratory. Dose distributions were recorded with gafchromic films, placed at the distal end of SPHINX and at several depths in a solid water phantom. The geometry of SPHINX and of the experimental set‐ups was also modeled in Monte Carlo (MC) simulations with the FLUKA code, used to reproduce the experimental results and, after validation, to predict and optimize the performance and design of the SPHINX.Results:The results indicate significant particle leakage through the channels during a single‐channel irradiation for high incident energies, followed by a rapid decrease for energies of clinical interest. When the collimator channels are used as target, the photon production increases, however at expense of the beam size that is also enlarged. The illumination of all channels simultaneously shows a fairly even transmission of the beam.Conclusion:With the measurements we have verified the MC models and the uniformity of beam transmission through SPHINX, and we have evaluated the importance of particle leakage through adjacent channels. These results can be used to optimize SPHINX design through the validated MC simulations.Funding: Weston Havens Foundation, Office of the Dean of Medical School and Office of the Provost (Stanford University).Loo, Maxim, Borchard, Tantawi are co‐founders of TibaRay Inc.Loo and Tantawi are TibaRay Inc. board members.Loo and Maxim received grants from Varian Medical Systems and RaySearch Laboratory.
TU‐H‐BRB‐00: Radiation Countermeasures Research and Development
Authors: Daniel J. 
Published: July 2016

The US government has substantial research and development activities underway for medical countermeasures that will insure the long‐term safety and survival of the country's population after unfortunate large‐scale biological, chemical and radiological and nuclear events. Preparedness includes research and development of medical countermeasures to address radiation‐induced cutaneous and internal injury from radiation and nuclear events as well as for minimizing radiation risks incurred during and after travel in space. Other important research and development efforts include the repurposing of countermeasures and development of radioprotectors and mitigators to improve the outcome of radiation treatment. Participating agencies include NIAID, BARDA, NCI, and NASA, with examples of research and development funding that includes the Centers for Medical Countermeasures against Radiation (CMCR) consortia (NIAID) and primary and sub‐contracts with commercial entities (BARDA). Each of these programs requires substantial medical and health physics effort in collaboration with biology colleagues to provide a range of radiation sources, dosimetry instrumentation and assessment methods, and animal models for specific radiation‐induced effects and injuries. Radiation countermeasure activities for government agencies will be reviewed, the importance of model development will be stressed, example radiation countermeasure research projects will be reviewed, and the roles for medical physicists will be discussed.

Learning Objectives:
Review US national radiation countermeasure activities.
Review the roles for medical physicists in radiation countermeasures research and development.
Understand specific physics challenges in radiation research that need solutions.Research for JD Bourland supported in part by: NIH/NIAID, U19 AI67798 (subcontract 131714). NIH/NCI, R01CA155293. HHSO10020130019C, BARDA/Argentum Medical LLC.; J. Bourland, Research supported in part by:NIH/NIAID, U19 AI67798 (subcontract 131714); NIH/NCI, R01CA155293; HHSO10020130019C, BARDA/Argentum Medical LLC.; P. Prasanna, Supported by the Radiation Research Program, National Cancer Institute
TU‐H‐BRB‐01: Physics and Dosimetry for Radiation Countermeasure Research
Authors: Bourland J. 
Published: July 2016

The US government has substantial research and development activities underway for medical countermeasures that will insure the long‐term safety and survival of the country's population after unfortunate large‐scale biological, chemical and radiological and nuclear events. Preparedness includes research and development of medical countermeasures to address radiation‐induced cutaneous and internal injury from radiation and nuclear events as well as for minimizing radiation risks incurred during and after travel in space. Other important research and development efforts include the repurposing of countermeasures and development of radioprotectors and mitigators to improve the outcome of radiation treatment. Participating agencies include NIAID, BARDA, NCI, and NASA, with examples of research and development funding that includes the Centers for Medical Countermeasures against Radiation (CMCR) consortia (NIAID) and primary and sub‐contracts with commercial entities (BARDA). Each of these programs requires substantial medical and health physics effort in collaboration with biology colleagues to provide a range of radiation sources, dosimetry instrumentation and assessment methods, and animal models for specific radiation‐induced effects and injuries. Radiation countermeasure activities for government agencies will be reviewed, the importance of model development will be stressed, example radiation countermeasure research projects will be reviewed, and the roles for medical physicists will be discussed.

Learning Objectives:
Review US national radiation countermeasure activities.
Review the roles for medical physicists in radiation countermeasures research and development.
Understand specific physics challenges in radiation research that need solutions.Research for JD Bourland supported in part by: NIH/NIAID, U19 AI67798 (subcontract 131714). NIH/NCI, R01CA155293. HHSO10020130019C, BARDA/Argentum Medical LLC.; J. Bourland, Research supported in part by:NIH/NIAID, U19 AI67798 (subcontract 131714); NIH/NCI, R01CA155293; HHSO10020130019C, BARDA/Argentum Medical LLC.; P. Prasanna, Supported by the Radiation Research Program, National Cancer Institute
TU‐H‐BRB‐02: The NIAID Radiation/Nuclear Medical Countermeasures Program
Authors: Taliaferro L. 
Published: July 2016

The US government has substantial research and development activities underway for medical countermeasures that will insure the long‐term safety and survival of the country's population after unfortunate large‐scale biological, chemical and radiological and nuclear events. Preparedness includes research and development of medical countermeasures to address radiation‐induced cutaneous and internal injury from radiation and nuclear events as well as for minimizing radiation risks incurred during and after travel in space. Other important research and development efforts include the repurposing of countermeasures and development of radioprotectors and mitigators to improve the outcome of radiation treatment. Participating agencies include NIAID, BARDA, NCI, and NASA, with examples of research and development funding that includes the Centers for Medical Countermeasures against Radiation (CMCR) consortia (NIAID) and primary and sub‐contracts with commercial entities (BARDA). Each of these programs requires substantial medical and health physics effort in collaboration with biology colleagues to provide a range of radiation sources, dosimetry instrumentation and assessment methods, and animal models for specific radiation‐induced effects and injuries. Radiation countermeasure activities for government agencies will be reviewed, the importance of model development will be stressed, example radiation countermeasure research projects will be reviewed, and the roles for medical physicists will be discussed.

Learning Objectives:
Review US national radiation countermeasure activities.
Review the roles for medical physicists in radiation countermeasures research and development.
Understand specific physics challenges in radiation research that need solutions.Research for JD Bourland supported in part by: NIH/NIAID, U19 AI67798 (subcontract 131714). NIH/NCI, R01CA155293. HHSO10020130019C, BARDA/Argentum Medical LLC.; J. Bourland, Research supported in part by:NIH/NIAID, U19 AI67798 (subcontract 131714); NIH/NCI, R01CA155293; HHSO10020130019C, BARDA/Argentum Medical LLC.; P. Prasanna, Supported by the Radiation Research Program, National Cancer Institute
TU‐H‐BRA‐07: Design, Construction, and Installation of An Experimental Beam Line for the Development of MRI‐Linac Compatible Electron Accelerator
Authors: Whelan B , Keall P , Holloway L , Gierman S , Schmerge J , Tantawi S , Tremaine A , Trautwein A , Scott B , Fahrig R 
Published: July 2016

Purpose:MRI guided radiation therapy (MRIgRT) is a rapidly growing field; however, Linac operation in MRI fringe fields represents an ongoing challenge. We have previously shown in‐silico that Linacs could be redesigned to function in the in‐line orientation with no magnetic shielding by adopting an RF‐gun configuration. Other authors have also published insilico studies of Linac operation in magnetic fields; however to date no experimental validation data is published. This work details the design, construction, and installation of an experimental beam line to validate our in‐silico results.Methods:An RF‐gun comprising 1.5 accelerating cells and capable of generating electron energies up to 3.2MeV is used. The experimental apparatus was designed to monitor both beam current (toroid current monitor), spot size (two phosphor screens with viewports), and generate peak magnetic fields of at least 1000G (three variable current electromagnetic coils). Thermal FEM simulations were developed to ensure coil temperature remained within 100degC. Other design considerations included beam disposal, vacuum maintenance, radiation shielding, earthquake safety, and machine protection interlocks.Results:The beam line has been designed, built, and installed in a radiation shielded bunker. Water cooling, power supplies, thermo‐couples, cameras, and radiation shielding have been successfully connected and tested. Interlock testing, vacuum processing, and RF processing have been successfully completed. The first beam on is expected within weeks. The coil heating simulations show that with care, peak fields of up to 1200G (320G at cathode) can be produced using 40A current, which is well within the fields expected for MRI‐Linac systems. The maximum coil temperature at this current was 84degC after 6 minutes.Conclusion:An experimental beam line has been constructed and installed at SLAC in order to experimentally characterise RF gun performance in in‐line magnetic fields, validate in‐silico design work, and provide the first published experimental data relating to accelerator functionality for MRIgRT.