bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐D‐201‐06: Random Walk Algorithm Seed Localization Parameters in Lung Positron Emission Tomography (PET) Images
Authors: Soufi M , Asl A Kamali , Geramifar P 
Published: June 2015

Purpose:The objective of this study was to find the best seed localization parameters in random walk algorithm application to lung tumor delineation in Positron Emission Tomography (PET) images.Methods:PET images suffer from statistical noise and therefore tumor delineation in these images is a challenging task. Random walk algorithm, a graph based image segmentation technique, has reliable image noise robustness. Also its fast computation and fast editing characteristics make it powerful for clinical purposes. We implemented the random walk algorithm using MATLAB codes. The validation and verification of the algorithm have been done by 4D‐NCAT phantom with spherical lung lesions in different diameters from 20 to 90 mm (with incremental steps of 10 mm) and different tumor to background ratios of 4:1 and 8:1. STIR (Software for Tomographic Image Reconstruction) has been applied to reconstruct the phantom PET images with different pixel sizes of 2×2×2 and 4×4×4 mm3. For seed localization, we selected pixels with different maximum Standardized Uptake Value (SUVmax) percentages, at least (70%, 80%, 90% and 100%) SUVmax for foreground seeds and up to (20% to 55%, 5% increment) SUVmax for background seeds. Also, for investigation of algorithm performance on clinical data, 19 patients with lung tumor were studied. The resulted contours from algorithm have been compared with nuclear medicine expert manual contouring as ground truth.Results:Phantom and clinical lesion segmentation have shown that the best segmentation results obtained by selecting the pixels with at least 70% SUVmax as foreground seeds and pixels up to 30% SUVmax as background seeds respectively. The mean Dice Similarity Coefficient of 94% ± 5% (83% ± 6%) and mean Hausdorff Distance of 1 (2) pixels have been obtained for phantom (clinical) study.Conclusion:The accurate results of random walk algorithm in PET image segmentation assure its application for radiation treatment planning and diagnosis.
SU‐E‐E‐01: Revamping the Classroom for An Active Learning Environment
Authors: Rutel IB 
Published: June 2015

Purpose:Removing traditional didactic lecture from session contact time provides the opportunity to keep the classroom interaction active, keeping both the students and instructor engaged.Methods:Participant survey evaluation analysis for a non‐traditional teaching environment during a technical graduate course, conducted over three course offerings (81 sessions, total) and 23 graduate medical physics student participants is offered. The modified course structure utilizes multiple alternate teaching methods, including the flipped classroom, online lecture offerings, peer teaching, problem based learning and guided discussions for each session. Viewing online lectures and textbook reading were prerequisites for class sessions, while scheduled open question time, guided interrogative sections, problem‐based whiteboard activities and peer teaching were the focus of class designated contact time. Effectiveness and student perception/satisfaction were gauged by end of course, participant survey responses (both scaled questions and free‐form response).Results:In general, students responded with positive feedback and indicated better understanding when the course was viewed as a whole. Granularity of understanding was further broken into the various components in broad categories which includes utilizing only the online lecture material, using only the interrogative classroom experience and the use of the text book as the sole source of learning material. Analysis of the survey results and a description of the classroom activities are presented.Conclusion:The modified classroom environment is conducive to more active engagement between the students and the instructor, leading to better perceived information retention and overall satisfaction with the course offering.
SU‐E‐E‐02: An Excel‐Based Study Tool for ABR‐Style Exams
Authors: Cline K , Stanley D , Defoor D , Stathakis S , Gutierrez A , Papanikolaou N , Kirby N 
Published: June 2015

Purpose:As the landscape of learning and testing shifts toward a computer‐based environment, a replacement for paper‐based methods of studying is desirable. Using Microsoft Excel, a study tool was developed that allows the user to populate multiple‐choice questions and then generate an interactive quiz session to answer them.Methods:The code for the tool was written using Microsoft Excel Visual Basic for Applications with the intent that this tool could be implemented by any institution with Excel. The base tool is a template with a setup macro, which builds out the structure based on user's input. Once the framework is built, the user can input sets of multiple‐choice questions, answer choices, and even add figures. The tool can be run in random‐question or sequential‐question mode for single or multiple courses of study. The interactive session allows the user to select answer choices and immediate feedback is provided. Once the user is finished studying, the tool records the day's progress by reporting progress statistics useful for trending.Results:Six doctoral students at UTHSCSA have used this tool for the past two months to study for their qualifying exam, which is similar in format and content to the American Board of Radiology (ABR) Therapeutic Part II exam. The students collaborated to create a repository of questions, met weekly to go over these questions, and then used the tool to prepare for their exam.Conclusion:The study tool has provided an effective and efficient way for students to collaborate and be held accountable for exam preparation. The ease of use and familiarity of Excel are important factors for the tool's use. There are software packages to create similar question banks, but this study tool has no additional cost for those that already have Excel. The study tool will be made openly available.
SU‐E‐E‐03: Shared Space Fosters Didactic and Professional Learning Across Professions for Medical and Physics Residents
Authors: Dieterich S , Perks J , Fragoso R 
Published: June 2015

Purpose:Medical Physicists and Radiation Oncologists are two professions who should be working as a team for optimal patient care, yet lack of mutual understanding about each others respective role and work environment creates barriers To improve collaboration and learning, we designed a shared didactic and work space for physics and radiation oncology residents to maximize interaction throughout their professional training.Methods:Physician and Physics residents are required to take the same didactic classes, including journal clubs and respective seminars. The residents also share an office environment among the seven physician and two physic residents.Results:By maximizing didactic overlap and sharing office space, the two resident groups have developed a close professional relationship and supportive work environment. Several joint research projects have been initiated by the residents. Awareness of physics tasks in the clinic has led to a request by the physician residents to change physics didactics, converting the physics short course into a lab‐oriented course for the medical residents which is in part taught by the physics residents. The physics seminar is given by both residency groups; increased motivation and interest in learning about physics has led to several medical resident‐initiated topic selections which generated lively discussion. The physics long course has changed toward including more discussion among residents to delve deeper into topics and study beyond what passing the boards would require. A supportive work environment has developed, embedding the two physics residents into a larger residents group, allowing them to find mentor and peers more easily.Conclusion:By creating a shared work and didactic environment, physician and physics residents have improved their understanding of respective professional practice. Resident‐initiated changes in didactic practice have led to improved learning and joint research. A strong social support system has developed, embedding physics residents into a larger peer group.
SU‐E‐E‐06: Teaching About the Gamma Camera and Ultrasound Imaging
Authors: Lowe M , Spiro A , Vogel R , Donaldson N , Gosselin C 
Published: June 2015

Purpose:Instructional modules on applications of physics in medicine are being developed. The target audience consists of students who have had an introductory undergraduate physics course. This presentation will concentrate on an active learning approach to teach the principles of the gamma camera. There will also be a description of an apparatus to teach ultrasound imaging.Methods:Since a real gamma camera is not feasible in the undergraduate classroom, we have developed two types of optical apparatus that teach the main principles. To understand the collimator, LEDS mimic gamma emitters in the body, and the photons pass through an array of tubes. The distance, spacing, diameter, and length of the tubes can be varied to understand the effect upon the resolution of the image. To determine the positions of the gamma emitters, a second apparatus uses a movable green laser, fluorescent plastic in lieu of the scintillation crystal, acrylic rods that mimic the PMTs, and a photodetector to measure the intensity. The position of the laser is calculated with a centroid algorithm.To teach the principles of ultrasound imaging, we are using the sound head and pulser box of an educational product, variable gain amplifier, rotation table, digital oscilloscope, Matlab software, and phantoms.Results:Gamma camera curriculum materials have been implemented in the classroom at Loyola in 2014 and 2015. Written work shows good knowledge retention and a more complete understanding of the material. Preliminary ultrasound imaging materials were run in 2015.Conclusion:Active learning methods add another dimension to descriptions in textbooks and are effective in keeping the students engaged during class time. The teaching apparatus for the gamma camera and ultrasound imaging can be expanded to include more cases, and could potentially improve students’ understanding of artifacts and distortions in the images.
SU‐E‐E‐15: Design of a Water Calorimeter for Dual Use in An Integrated MRI‐Linac and Gamma‐Knife
Authors: Entezari N , Renaud J , Ly D , Sarfehnia A 
Published: June 2015

Purpose:To design a water calorimeter for dual use in an integrated MRI‐linac and Gamma‐Knife. In calorimetry, dose to water is measured based on the assumption that energy absorbed in a sensitive volume is completely converted to temperature rise ₍ΔΤ₎ according to the specific heat capacity of the medium c: D=c*ΔT*k, where k is heat transfer correction factor and compensates for heat gain or loss at point of measurement due to conductive effects.Methods:A commercial finite element method software package was used to model four different water calorimeter designs. The long term (48 h) thermal stability of each design was accurately modeled, and the optimization of the final design was based on evaluation of the standard deviation of k for ten consecutive irradiation runs (lower standard deviation translates to greater thermal stability). Several insulator materials of varying thicknesses were investigated, and a sensitivity study of thermal stability to variations in ambient temperature fluctuations was undertaken. Specifically, we evaluated the effect of possible variations in coolant temperature circulating around the calorimeter tank in several scenarios (constant, slowly increasing, or fluctuating).Results:Due to MRI‐compatibility requirements, the calorimeter is to be built entirely out of plastic. Among all insulation materials tested, solid state aerogel‐based insulation resulted in least heat loss and thermal stability. The final design is cylindrical on top (to be used upright in MRI‐linac) and semi‐spherical at bottom (for use in GammaKnife). The range of k was found to be 1.002 ± 0.013 (k = 1), comparable with a k of 1.002 ± 0.014 for typical water calorimeters used in high energy beams. A long term stability of 0.36 µK/hr was evaluated.Conclusion:Optimization of a water calorimeter design for dual use in MRI‐linac and Gamma‐Knife has been completed and the device is currently in production.Supported by NSERC RGPIN 435608
SU‐E‐P‐05: Electronic Brachytherapy: A Physics Perspective On Field Implementation
Authors: Pai S , Ayyalasomayajula S , Lee S 
Published: June 2015

Purpose:We want to summarize our experience implementing a successful program of electronic brachytherapy at several dermatology clinics with the help of a cloud based software to help us define the key program parameters and capture physics QA aspects. Optimally developed software helps the physicist in peer review and qualify the physical parameters.Methods:Using the XOFT™ Axxent™ electronic brachytherapy system in conjunction with a cloud‐based software, a process was setup to capture and record treatments. It was implemented initially at about 10 sites in California. For dosimetric purposes, the software facilitated storage of the physics parameters of surface applicators used in treatment and other source calibration parameters. In addition, the patient prescription, pathology and other setup considerations were input by radiation oncologist and the therapist. This facilitated physics planning of the treatment parameters and also independent check of the dwell time. From 2013–2014, nearly1500 such calculation were completed by a group of physicists. A total of 800 patients with multiple lesions have been treated successfully during this period. The treatment log files have been uploaded and documented in the software which facilitated physics peer review of treatments per the standards in place by AAPM and ACR.Results:The program model was implemented successfully at multiple sites. The cloud based software allowed for proper peer review and compliance of the program at 10 clinical sites. Dosimtery was done on 800 patients and executed in a timely fashion to suit the clinical needs. Accumulated physics data in the software from the clinics allows for robust analysis and future development.Conclusion:Electronic brachytherapy implementation experience from a quality assurance perspective was greatly enhanced by using a cloud based software. The comprehensive database will pave the way for future developments to yield superior physics outcomes.
SU‐E‐P‐06: A Graphical User Interface (GUI) Toolkit Created for Multi‐Phase Biological Effective Dose (BED) Calculations Including Statistical Analyses
Authors: Kauweloa K , Gutierrez A , Stathakis S , Papanikolaou N , Mavroidis P 
Published: June 2015

Purpose:There is growing interest amongst clinics in applying the biological effective dose (BED) to their treatment plan evaluations, as well as potential optimizations due to its stronger correlation with radiobiological effects. An approximate, multi‐phase biological effective dose (BEDA) equation was introduced in order to simplify BED calculations using many current treatment planning systems (TPS). The purpose of this work is to create a MATLAB graphical user interface (GUI) in order to determine the accuracy and precision of BEDA in common clinical treatments.Methods:A number of algorithms were written in order to read exported treatment plans from the TPS Pinnacle. Those algorithms were then tested and compared with the results on Pinnacle in order to determine its accuracy. BED algorithms were then created in order to calculate the BEDT and BEDA distributions. The algorithms for the DVH statistics, the Bland‐Altman Analysis, and the Percent Error were written and added to this GUI in order to study the accuracy and precision of BEDA.Results:When comparing the DVH results from the created MATLAB GUI to those from Pinnacle, there was less than a 1% difference in the dose distribution statistics such as the maximum, minimum, mean, and standard deviation for the dose in the specific region of interest. The amount of time needed to calculate the BED distributions ranged anywhere from 5 to 90 seconds due to its dependence on the size of the dose distribution matrix.Conclusion:Due to the dose distribution accuracy, it is safe to use this MATLAB GUI toolkit to study the approximate BED calculation method. It can also be used to analyze patient treatment plans using the true BED distributions and the biological effective dose volume histograms (BEDVHs). In addition, further studies can be performed in determining BED constraints for different organs and endpoints.
SU‐E‐P‐07: Retrospective Analysis of Incident Reports at a Radiology Department: Feedback From Incident Reporting System
Authors: Kakinohana Y , Toita T , Heianna J , Murayama S 
Published: June 2015

Purpose:To provide an overview of reported incidents that occurred in a radiology department and to describe the most common causal source of incidents.Methods:Incident reports from the radiology department at the University of the Ryukyus Hospital between 2008 and 2013 were collected and analyzed retrospectively. The incident report form contains the following items, causal factors of the incident and desirable corrective actions to prevent recurrence of similar incidents. These items allow the institution to investigate/analyze root causes of the incidents and suggest measures to be taken to prevent further, similar incidents. The ‘causal factors of the incident’ item comprises multiple selections from among 24 selections and includes some synonymous selections. In this study, this item was re‐categorized into four causal source types: (i) carelessness, (ii) lack of skill or knowledge, (iii) deficiencies in communication, and (iv) external factors.Results:There were a total of 7490 incident reports over the study period and 276 (3.7%) were identified as originating from the radiology department. The most frequent causal source type was carelessness (62%). The other three types showed similar frequencies (10–14%). The staff members involved in incidents indicate three predominant desirable corrective actions to prevent or decrease the recurrence of similar incidents. These are ‘improvement in communication’ (24%), ‘staff training/education’ (19%), and ‘daily medical procedures’ (22%), and the most frequent was ‘improvement in communication’. Even though the most frequent causal factor was related to carelessness, the most desirable corrective action indicated by the staff members was related to communication.Conclusion:Our finding suggests that the most immediate causes are strongly related to carelessness. However, the most likely underlying causes of incidents would be related to deficiencies in effective communication. At our department, therefore, the primary action to prevent/reduce similar incidents should be ‘communication improvement’.
SU‐E‐P‐13: Quantifying the Geometric Error Due to Irregular Motion in Four‐Dimensional Computed Tomography (4DCT)
Authors: Sawant A 
Published: June 2015

Purpose:Respiratory correlated 4DCT images are generated under the assumption of a regular breathing cycle. This study evaluates the error in 4DCT‐based target position estimation in the presence of irregular respiratory motion.Methods:A custom‐made programmable externally‐and internally‐deformable lung motion phantom was placed inside the CT bore. An abdominal pressure belt was placed around the phantom to mimic clinical 4DCT acquisitio and the motion platform was programmed with a sinusoidal (±10mm, 10 cycles per minute) motion trace and 7 motion traces recorded from lung cancer patients. The same setup and motion trajectories were repeated in the linac room and kV fluoroscopic images were acquired using the on‐board imager. Positions of 4 internal markers segmented from the 4DCT volumes were overlaid upon the motion trajectories derived from the fluoroscopic time series to calculate the difference between estimated (4DCT) and “actual” (kV fluoro) positions.Results:With a sinusoidal trace, absolute errors of the 4DCT estimated markers positions vary between 0.78mm and 5.4mm and RMS errors are between 0.38mm to 1.7mm. With irregular patient traces, absolute errors of the 4DCT estimated markers positions increased significantly by 100 to 200 percent, while the corresponding RMS error values have much smaller changes. Significant mismatches were frequently found at peak‐inhale or peak‐exhale phase.Conclusion:As expected, under conditions of well‐behaved, periodic sinusoidal motion, the 4DCT yielded much better estimation of marker positions. When an actual patient trace is used 4DCT‐derived positions showed significant mismatches with the fluoroscopic trajectories, indicating the potential for geometric and therefore dosimetric errors in the presence of cycle‐to‐cycle respiratory variations.
SU‐E‐P‐17: Flipping the Classroom: Improving Physics Education in a Clinical Environment
Authors: Rasmussen K , Ferreira C , Corbett M , Stephenson S , Naves J 
Published: June 2015

Purpose:The traditional model of an active presenter with a passive audience is one of the least effective methods of education availiable.1 Additionally, it is difficult for an instructor to balance time preparing for course lectures with clinical duties. An alternative method would be to reduce the amount of lecture time in the class, with a greater emphasis on outside readings or videos that students watch prior to attending scheduled class hours.Methods:The Clinical Rotation course at ECU was revamped to incorporate >30 TG Reports to develop deeper understanding of clinical aspects. Students were expected to read and bring questions on the topics to a weekly discussion session. Additional questions were asked by the instructor to verify understanding and emphasize key points of the reports. A final oral exam was given in the style of ABR part 3 to determine comprehensive analysis of the students understanding.Results:Over the past five semesters of the course, students have consistently had positive feedback on the course and overall scores have been good. Students benefited greatly from active learning during class discussions. A comparison with previous average grades was not possible. Time for preparation of the discussion is greatly reduced from time consuming powerpoint presentations.Conclusion:It is important to balance time in clinic and time teaching to optimize efficiency in education without sacrificing patient care. It is also important to deliver a quality education to students. This method also has the added benefit of emphasizing the importance of task group reports to students which will be a primary source of reference in clinical settings.1McIntosh, N.,&Sullivan, N. (1996). Delivering effective lectures. JHPIEGO Strategy Papers.