bluuebunny/crossref_metadata_2025_split huggingface dataset:
MO‐C‐17A‐11: A Segmentation and Point Matching Enhanced Deformable Image Registration Method for Dose Accumulation Between HDR CT Images
Authors: Zhen X , Chen H , Yan H , Zhou L , Mell L , Yashar C , Jiang S , Jia X , Gu X , Cervino L 
Published: July 2014

Purpose:To propose and validate a novel and accurate deformable image registration (DIR) scheme to facilitate dose accumulation among treatment fractions of high‐dose‐rate (HDR) gynecological brachytherapy.Method:We have developed a method to adapt DIR algorithms to gynecologic anatomies with HDR applicators by incorporating a segmentation step and a point‐matching step into an existing DIR framework. In the segmentation step, random walks algorithm is used to accurately segment and remove the applicator region (AR) in the HDR CT image. A semi‐automatic seed point generation approach is developed to obtain the incremented foreground and background point sets to feed the random walks algorithm. In the subsequent point‐matching step, a feature‐based thin‐plate spline‐robust point matching (TPS‐RPM) algorithm is employed for AR surface point matching. With the resulting mapping, a DVF characteristic of the deformation between the two AR surfaces is generated by B‐spline approximation, which serves as the initial DVF for the following Demons DIR between the two AR‐free HDR CT images. Finally, the calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions.Results:The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative results as well as the visual inspection of the DIR indicate that our proposed method can suppress the interference of the applicator with the DIR algorithm, and accurately register HDR CT images as well as deform and add interfractional HDR doses.Conclusions:We have developed a novel and robust DIR scheme that can perform registration between HDR gynecological CT images and yield accurate registration results. This new DIR scheme has potential for accurate interfractional HDR dose accumulation.This work is supported in part by the National Natural ScienceFoundation of China (no 30970866 and no 81301940).
MO‐D‐BRF‐01: Pediatric Treatment Planning II: The PENTEC Report On Normal Tissue Complications
Authors: Constine L , Hodgson D , Bentzen S 
Published: July 2014

With advances in multimodality therapy, childhood cancer cure rates approach 80%. However, both radiotherapy and chemotherapy may cause debilitating or even fatal ‘late effects’ that are critical to understand, mitigate, or prevent. QUANTEC identified the uncertainties relating to side‐effects of adult treatments, but this is more complicated for children in whom a mosaic of tissues develops at different rates and temporal sequences. Childhood cancer survivors have long life expectancy and may develop treatmentinduced secondary cancers and severe organ/tissue injury decades after treatment. Collaborative long‐term observational studies and clinical research programs for survivors of pediatric and adolescent cancer provide some dose‐response data for follow‐up periods exceeding 40 years. Data analysis is challenging due to the influence of both therapeutic and developmental variables. PENTEC is a group of radiation oncologists, pediatric oncologists, subsepcialty physicians, medical physicists, biomathematic modelers/statisticians, and epidemiologists charged with conducting a critical synthesis of existing literature aiming to: critically analyze radiation dose‐volume effects on normal tissue tolerances as a function of age/development in pediatric cancer patients in order to inform treatment planning and improve outcomes for survivors; describe relevant physics issues specific to pediatric radiotherapy; propose dose‐volumeoutcome reporting standards to improve the knowledge base to inform future treatment guidelines. PENTEC has developed guidelines for systematic literature reviews, data extraction tolls and data analysis.This education session will discuss:1. Special considerations for normal tissue radiation response of children/adolescents, e.g. the interplay between development and radiotherapy effects.2. Epidemiology of organ/tissue injuries and secondary cancers.3. Exploration of dose‐response differences between children and adults4. Methodology for literature review, data mining of outcomes databases, and NTCP or longitudinal modeling of doseresponse. 5. PENTEC goals and timetable.Learning Objectives:

Understand important differences between normal tissue effects of radiation therapy in pediatric and adult patients.
Be able to identify situations where there is ‘interplay’ between organ development and radiation‐induced complications.
Identify methods to systematically extract quantitative dose‐volumeresponse relationships from existing outcomes databases.
Provide guidance for the medical physicist to properly understand, implement, guide and control contemporary technology and applications in pediatric radiation oncology.
MO‐E‐16A‐01: Preparing for the ABR Therapy Medical Physics Exam
Authors: Galavis P , Chinsky B , Becker S 
Published: July 2014

Preparing for all three parts of the Therapy ABR Physics boards is more than just studying as much material as possible. There will always be material that is missed and gaps in one's knowledge. Therefore it is crucial to understand how the materials relate to each other and to clinical experiences in order to fill those gaps.Each part of the board exam presents its own difficulties:Part I: Determining what material to study, most of which have been learned a long time ago.Part II: Solving a vast array of clinical calculations rapidly by handPart III: Gaining crucial clinical experiences and being able to explain orally how they are performed and what they mean.All three require different skill sets and preparation, from memorizing vast amounts of material, to rapidly recognizing and solving calculations, to being able to easily and confidently respond to oral questions about all aspects of working in the clinic and why those clinical methods and procedures are performed that way. This symposium is not a comprehensive review of all required study material. Instead it focuses on the previously mentioned problems and required skill sets that are needed for each part of the board exam. Expert Medical Physicists will share their experiences and methods to help students best prepare for the challenges of each individual exam.Learning Objectives:

How to Prepare for Part 1 by determining study material
How to Prepare for Part 2 by learning to solve clinical calculations rapidly
How to Prepare for Part 3 by determining critical clinical experiences and learning how to answer questions orally
MO‐E‐BRF‐01: Research Opportunities in Technology for Innovation in Radiation Oncology (Highlight of ASTRO NCI 2013 Workshop)
Authors: Hahn S , Jaffray D , Chetty I , Benedict S 
Published: July 2014

Radiotherapy is one of the most effective treatments for solid tumors, in large part due to significant technological advances associated with, for instance, the ability to target tumors to very high levels of accuracy (within millimeters). Technological advances have played a central role in the success of radiation therapy as an oncologic treatment option for patients. ASTRO, AAPM and NCI sponsored a workshop “Technology for Innovation in Radiation Oncology” at the NCI campus in Bethesda, MD on June 13–14, 2013. The purpose of this workshop was to bring together expert clinicians and scientists to discuss the role of disruptive technologies in radiation oncology, in particular with regard to how they are being developed and translated to clinical practice in the face of current and future challenges and opportunities. The technologies discussed encompassed imaging and delivery aspects, along with methods to enable/facilitate application of them in the clinic. Measures for assessment of the performance of these technologies, such as techniques to validate quantitative imaging, were reviewed. Novel delivery technologies, incorporating efficient and safe delivery mechanisms enabled by development of tools for process automation and the associated field of oncology informatics formed one of the central themes of the workshop. The discussion on disruptive technologies was grounded in the need for evidence of efficacy. Scientists in the areas of technology assessment and bioinformatics provided expert views on different approaches toward evaluation of technology efficacy. Clinicians well versed in clinical trials incorporating disruptive technologies (e.g. SBRT for early stage lung cancer) discussed the important role of these technologies in significantly improving local tumor control and survival for these cohorts of patients. Recommendations summary focused on the opportunities associated with translating the technologies into the clinic and assessing their efficacy, and provided a glimpse into the future.Learning Objectives:

To understand the impact of technology on the field of radiation therapy
To learn about the trends of technology development for the field of radiation oncology
To understand the opportunities for in innovative technology research
MO‐E‐17A‐03: Monte Carlo CT Dose Calculation: A Comparison Between Experiment and Simulation Using ARCHER‐CT
Authors: Liu T , Du X , Su L , Gao Y , Ji W , Zhang D , Shi J , Liu B , Kalra M , Xu X 
Published: July 2014

Purpose:To compare the CT doses derived from the experiments and GPU‐based Monte Carlo (MC) simulations, using a human cadaver and ATOM phantom.Methods:The cadaver of an 88‐year old male and the ATOM phantom were scanned by a GE LightSpeed Pro 16 MDCT. For the cadaver study, the Thimble chambers (Model 10×5−0.6CT and 10×6−0.6CT) were used to measure the absorbed dose in different deep and superficial organs. Whole‐body scans were first performed to construct a complete image database for MC simulations. Abdomen/pelvis helical scans were then conducted using 120/100 kVps, 300 mAs and a pitch factor of 1.375:1. For the ATOM phantom study, the OSL dosimeters were used and helical scans were performed using 120 kVp and x, y, z tube current modulation (TCM). For the MC simulations, sufficient particles were run in both cases such that the statistical errors of the results by ARCHER‐CT were limited to 1%.Results:For the human cadaver scan, the doses to the stomach, liver, colon, left kidney, pancreas and urinary bladder were compared. The difference between experiments and simulations was within 19% for the 120 kVp and 25% for the 100 kVp. For the ATOM phantom scan, the doses to the lung, thyroid, esophagus, heart, stomach, liver, spleen, kidneys and thymus were compared. The difference was 39.2% for the esophagus, and within 16% for all other organs.Conclusion:In this study the experimental and simulated CT doses were compared. Their difference is primarily attributed to the systematic errors of the MC simulations, including the accuracy of the bowtie filter modeling, and the algorithm to generate voxelized phantom from DICOM images. The experimental error is considered small and may arise from the dosimeters.R01 grant (R01EB015478) from National Institute of Biomedical Imaging and Bioengineering
MO‐E‐17A‐04: Size‐Specific Dose Estimate (SSDE) Provides a Simple Method to Calculate Organ Dose for Pediatric CT Examinations
Authors: Moore B , Brady S , Mirro A , Kaufman R 
Published: July 2014

Purpose:Investigate the correlation of SSDE with organ dose in a pediatric population.Methods:Four anthropomorphic phantoms, representing a range of pediatric body habitus, were scanned with MOSFET dosimeters placed at 23 organ locations to determine absolute organ dosimetry. Phantom organ dosimetry was divided by phantom SSDE to determine correlation between organ dose and SSDE. Correlation factors were then multiplied by patient SSDE to estimate patient organ dose. Patient demographics consisted of 352 chest and 241 abdominopelvic CT examinations, 22 ± 15 kg (range 5−55 kg) mean weight, and 6 ± 5 years (range 4 mon to 23 years) mean age. Patient organ dose estimates were compared to published pediatric Monte Carlo study results.Results:Phantom effective diameters were matched with patient population effective diameters to within 4 cm. 23 organ correlation factors were determined in the chest and abdominopelvic region across nine pediatric weight subcategories. For organs fully covered by the scan volume, correlation in the chest (average 1.1; range 0.7−1.4) and abdominopelvic (average 0.9; range 0.7−1.3) was near unity. For organs that extended beyond the scan volume (i.e., skin, bone marrow, and bone surface), correlation was determined to be poor (average 0.3; range: 0.1−0.4) for both the chest and abdominopelvic regions, respectively. Pediatric organ dosimetry was compared to published values and was found to agree in the chest to better than an average of 5% (27.6/26.2) and in the abdominopelvic region to better than 2% (73.4/75.0).Conclusion:Average correlation of SSDE and organ dosimetry was found to be better than ± 10% for fully covered organs within the scan volume. This study provides a list of organ dose correlation factors for the chest and abdominopelvic regions, and describes a simple methodology to estimate individual pediatric patient organ dose based on patient SSDE.
MO‐E‐17A‐08: Attenuation‐Based Size Adjusted, Scanner‐Independent Organ Dose Estimates for Head CT Exams: TG 204 for Head CT
Authors: McMillan K , Bostani M , Zankl M , DeMarco J , Cagnon C , McNitt‐Gray M 
Published: July 2014

Purpose:AAPM Task Group 204 described size specific dose estimates (SSDE) for body scans. The purpose of this work is to use a similar approach to develop patient‐specific, scanner‐independent organ dose estimates for head CT exams using an attenuation‐based size metric.Methods:For eight patient models from the GSF family of voxelized phantoms, dose to brain and lens of the eye was estimated using Monte Carlo simulations of contiguous axial scans for 64‐slice MDCT scanners from four major manufacturers. Organ doses were normalized by scannerspecific 16 cm CTDIvol values and averaged across all scanners to obtain scanner‐independent CTDIvol‐to‐organ‐dose conversion coefficients for each patient model. Head size was measured at the first slice superior to the eyes; patient perimeter and effective diameter (ED) were measured directly from the GSF data. Because the GSF models use organ identification codes instead of Hounsfield units, water equivalent diameter (WED) was estimated indirectly. Using the image data from 42 patients ranging from 2 weeks old to adult, the perimeter, ED and WED size metrics were obtained and correlations between each metric were established. Applying these correlations to the GSF perimeter and ED measurements, WED was calculated for each model. The relationship between the various patient size metrics and CTDIvol‐to‐organ‐dose conversion coefficients was then described.Results:The analysis of patient images demonstrated the correlation between WED and ED across a wide range of patient sizes. When applied to the GSF patient models, an exponential relationship between CTDIvol‐to‐organ‐dose conversion coefficients and the WED size metric was observed with correlation coefficients of 0.93 and 0.77 for the brain and lens of the eye, respectively.Conclusion:Strong correlation exists between CTDIvol normalized brain dose and WED. For the lens of the eye, a lower correlation is observed, primarily due to surface dose variations.Funding Support: Siemens‐UCLA Radiology Master Research Agreement; Disclosures – Michael McNitt‐Gray: Institutional Research Agreement, Siemens AG; Research Support, Siemens AG; Consultant, Flaherty Sensabaugh Bonasso PLLC; Consultant, Fulbright and Jaworski
MO‐E‐17A‐09: Has Cancer Risk for Pediatric CT Increased Or Decreased? An Analysis of Cohort Data From 2004‐2013
Authors: Brady S , Kaufman R 
Published: July 2014

Purpose:To analyze CT radiation dosimetry trends in a pediatric population imaged with modern (2004‐2013) CT technologyMethods:The institutional review board approved this retrospective review. Two cohorts of pediatric patients that received CT scans for treatment or surveillance for Wilms tumor (n=73) or Neuroblastoma (n=74) from 2004–2013 were included in this study. Patients were scanned during this time period on a GE Ultra (8 slice; 2004–2007), a GE VCT (2008–2011), or a GE VCT‐XTe (2011–2013). Each patient's individual or combined chest, abdomen, and pelvic CT exams (n=4138) were loaded onto a PACS workstation (Intelerad, Canada) and measured to calculate their effective diameter and SSDE. Patient SSDE was used to estimate patient organ dosimetry based on previously published data. Patient's organ dosimetry were sorted by gender, weight, age, scan protocol (i.e., chest, abdomen, or pelvis), and CT scanner technology and averaged accordingly to calculate population averaged absolute and effective dose values.Results:Patient radiation dose burden calculated for all genders, weights, and ages decreased at a rate of 0.2 mSv/year (4.2 mGy/year; average organ dose) from 2004–2013; overall levels decreased by 50% from 3.0 mSv (60.0 mGy) to 1.5 mSv (25.9 mGy). Patient dose decreased at equal rates for both male and female, and for individual scan protocols. The greatest dose savings was found for patients between 0–4 years old (65%) followed by 5‐9 years old (45%), 10–14 years old (30%), and > 14 years old (21%).Conclusion:Assuming a linear‐nothreshold model, there always will be potential risk of cancer induction from CT. However, as demonstrated among these patient populations, effective and organ dose has decreased over the last decade; thus, potential risk of long‐term side effects from pediatric CT examinations has also been reduced.
MO‐E‐17A‐10: Evaluation of Body and Head Dimensions of Pediatric Patients as a Function of Age
Authors: Seibert JA , Boone JM 
Published: July 2014

Purpose:Phantom development in medical physics plays an important role in radiation dose assessment and image quality evaluation, and this is especially true in the pediatric patient population. The purpose of this investigation was to establish the relationship between patient age and patient size, focusing on the abdomen‐pelvis and head effective diameters, for patients ranging in age from newborn to 18 years.Methods:A dose reporting tool for computed tomography systems was installed at our institution to achieve compliance with state law commencing on July 1, 2012. The software records a number of patient‐specific data, and also reports CT dose metrics (CTDIvol and DLP) into the patients interpretive report. The database generated by the software was mined to determine patient effective diameter as a function of age for pediatric patients aged 0–18 years. CT protocols including abdomen‐pelvis and routine head were evaluated, and specific to this study the patients age, gender and equivalent diameter were recorded.Results:Six age ranges were evaluated: A(0–3), B(4–6), C(7–9), D(10–12),E(13–15),F(16–18). For the torso in these groups based upon 694 patients, median effective diameters were 147, 167, 184, 214, 231, 246 mm, respectively. For the head (N=1833), median diameters were 143, 157, 162, 168, 174, and 174, respectively.Conclusion:A solid understanding of the approximate dimensions of pediatric patients as a function of age is useful in the development of age‐based imaging protocols and dose assessments. CT dose‐reporting tools generate a great deal of data with respect to body dimensions automatically. In this study, median equivalent diameters for the abdomen‐pelvis and head of pediatric patients were evaluated. These data may prove useful in the development of both mathematical and physical phantoms for dosimetry and image quality assessment.
MO‐F‐16A‐02: Simulation of a Medical Linear Accelerator for Teaching Purposes
Authors: Carlone M , Lamey M , Anderson R , MacPherson M 
Published: July 2014

Purpose:Detailed functioning of linear accelerator physics is well known. Less well developed is the basic understanding of how the adjustment of the linear accelerator's electrical components affects the resulting radiation beam. Other than the text by Karzmark, there is very little literature devoted to the practical understanding of linear accelerator functionality targeted at the radiotherapy clinic level. The purpose of this work is to describe a simulation environment for medical linear accelerators with the purpose of teaching linear accelerator physics.Methods:Varian type lineacs were simulated. Klystron saturation and peak output were modelled analytically. The energy gain of an electron beam was modelled using load line expressions. The bending magnet was assumed to be a perfect solenoid whose pass through energy varied linearly with solenoid current. The dose rate calculated at depth in water was assumed to be a simple function of the target's beam current. The flattening filter was modelled as an attenuator with conical shape, and the time‐averaged dose rate at a depth in water was determined by calculating kerma.Results:Fifteen analytical models were combined into a single model called SIMAC. Performance was verified systematically by adjusting typical linac control parameters. Increasing klystron pulse voltage increased dose rate to a peak, which then decreased as the beam energy was further increased due to the fixed pass through energy of the bending magnet. Increasing accelerator beam current leads to a higher dose per pulse. However, the energy of the electron beam decreases due to beam loading and so the dose rate eventually maximizes and the decreases as beam current was further increased.Conclusion:SIMAC can realistically simulate the functionality of a linear accelerator. It is expected to have value as a teaching tool for both medical physicists and linear accelerator service personnel.
MO‐F‐16A‐08: Have An Impact On More Patients From Your Ideas And Inventions
Authors: Morton R 
Published: July 2014

Purpose:To inform physicists how to obtain an FDA 510(k) clearance for the innovations they use in their facility and to make those ideas widely available to patients throughout the U.S.Methods:Give advice from 20 years experience of assisting in well over 100 successful 510(k) clearances.Results:Learn how to develop a 510(k) submission.Conclusion:Many physicists, physicians and radiation therapists have developed innovations that that are helpful to the patients in their institution. But, many of these innovations deserve to be made available to patients throughout the United States. The author, a Certified Radiological Physicist and former FDA employee, has consulted for over twenty years for inventors, start‐ups and established medical device manufacturers to bring new devices to market in the U.S. and to assist them to established FDA compliant quality systems for manufacturing. In this presentation the audience will learn the important points for deciding to go forward with obtaining a Premarket Notification clearance [also known as a 510(k) clearance] to legally market a medical device in the United States. The FDA has published guidelines for submitting a 510(k) application. However, the methods used to efficiently develop the documentation for submission and to obtain clearance in the shortest possible time comes from the author's experience in assisting well over one hundred successful 510(k) clearances.Whether you want to start your own company or to market your idea to an established medical device manufacturer, the value of your innovation increases with a documented 510(k) clearance from FDA.