bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐D‐9A‐04: Brain PET/CT Imaging On a Scanner with a Large Axial Field‐Of‐View
Authors: Park M , Gerbaudo V , Hamberg L , Seaver K , Kijewski M 
Published: July 2014

Purpose:Large axial field‐of‐view (FOV) PET/CT scanners are valued for high sensitivity. Brain PET image quality may depend on the head position within the FOV. We investigated the precision of activity estimation for brain PET imaging when the brain was positioned at the end (END) and in the middle (CEN) of the FOV. The additional CT dose for the CEN position was recorded.Methods:An image quality (Jaszczak) phantom and a striatal phantom were filled with F‐18 and positioned in END and CEN locations. For each phantom and each location, we acquired a ∼1‐hr listmode PET, rebinned the data into 10 frames with equal number of coincidence events, and reconstructed each frame using an iterative algorithm. For the striatal phantom, END and CEN were compared by drawing on each image three regions of interest (ROI) in axially separated uniform areas. The standard deviation of the activity estimation within each ROI was averaged over the 10 images. The coefficient of variation (CV) for activity estimation was calculated at each position. Image quality was assessed by inspecting the resolution bar pattern in the Jaszczak phantom at two different head positions.Results:The CV was the lowest for ROIs near the center of the FOV. For slices near the end, not only was the CV highest, but also the resolution pattern was degraded. CTDIvol summarized in the dose report indicated that the CT dose was ∼ 10% higher for CEN as compared to END position.Conclusion:Positioning the brain in the middle of the FOV in a large FOV PET/CT scanner allows more precise measurement of tracer uptake and better image quality at the cost of increased CT dose. For the end location longer scan times may minimize image quality degradation without any additional CT dose.
SU‐D‐9A‐06: 3D Localization of Neurovascular Bundles Through MR‐TRUS Registration in Prostate Radiotherapy
Authors: Yang X , Rossi P , Ogunleye T , Jani A , Curran W , Liu T 
Published: July 2014

Purpose:Erectile dysfunction (ED) is the most common complication of prostate‐cancer radiotherapy (RT) and the major mechanism is radiation‐induced neurovascular bundle (NVB) damage. However, the localization of the NVB remains challenging. This study's purpose is to accurately localize 3D NVB by integrating MR and transrectal ultrasound (TRUS) images through MR‐TRUS fusion.Methods:T1 and T2‐weighted MR prostate images were acquired using a Philips 1.5T MR scanner and a pelvic phase‐array coil. The 3D TRUS images were captured with a clinical scanner and a 7.5 MHz biplane probe. The TRUS probe was attached to a stepper; the B‐mode images were captured from the prostate base to apex at a 1‐mm step and the Doppler images were acquired in a 5‐mm step. The registration method modeled the prostate tissue as an elastic material, and jointly estimated the boundary condition (surface deformation) and the volumetric deformations under elastic constraint. This technique was validated with a clinical study of 7 patients undergoing RT treatment for prostate cancer. The accuracy of our approach was assessed through the locations of landmarks, as well as previous ultrasound Doppler images of patients.Results:MR‐TRUS registration was successfully performed for all patients. The mean displacement of the landmarks between the post‐registration MR and TRUS images was 1.37±0.42 mm, which demonstrated the precision of the registration based on the biomechanical model; and the NVB volume Dice Overlap Coefficient was 92.1±3.2%, which demonstrated the accuracy of the NVB localization.Conclusion:We have developed a novel approach to improve 3D NVB localization through MR‐TRUS fusion for prostate RT, demonstrated its clinical feasibility, and validated its accuracy with ultrasound Doppler data. This technique could be a useful tool as we try to spare the NVB in prostate RT, monitor NBV response to RT, and potentially improve post‐RT potency outcomes.
SU‐D‐12A‐02: DeTECT, a Method to Enhance Soft Tissue Contrast From Mega Voltage CT
Authors: Sheng K , Gou S , Qi S 
Published: July 2014

Purpose:MVCT images have been used on TomoTherapy system to align patients based on bony anatomies but its usefulness for soft tissue registration, delineation and adaptive radiation therapy is severely limited due to minimal photoelectric interaction and prominent presence of noise resulting from low detector quantum efficiency of megavoltage x‐rays. We aim to utilize a non‐local means denoising method and texture analysis to recover the soft tissue information for MVCT.Methods:A block matching 3D (BM3D) algorithm was adapted to reduce the noise while keeping the texture information of the MVCT images. BM3D is an imaging denoising algorithm developed from non‐local means methods. BM3D additionally creates 3D groups by stacking 2D patches by the order of similarity. 3D denoising operation is then performed. The resultant 3D group is inversely transformed back to 2D images. In this study, BM3D was applied to MVCT images of a CT quality phantom, a head and neck and a prostate patient. Following denoising, imaging texture was enhanced to create the denoised and texture enhanced CT (DeTECT).Results:The original MVCT images show prevalent noise and poor soft tissue contrast. By applying BM3D denoising and texture enhancement, all MVCT images show remarkable improvements. For the phantom, the contrast to noise ratio for the low contrast plug was improved from 2.2 to 13.1 without compromising line pair conspicuity. For the head and neck patient, the lymph nodes and vein in the carotid space inconspicuous in the original MVCT image becomes highly visible in DeTECT. For the prostate patient, the boundary between the bladder and the prostate in the original MVCT is successfully recovered. Both results are visually validated by kVCT images of the corresponding patients.Conclusion:DeTECT showed the promise to drastically improve the soft tissue contrast of MVCT for image guided radiotherapy and adaptive radiotherapy.
SU‐D‐12A‐07: Optimization of a Moving Blocker System for Cone‐Beam Computed Tomography Scatter Correction
Authors: Ouyang L , Yan H , Zhang H , Jia X , Jiang S , Wang J 
Published: July 2014

Purpose:A moving blocker based strategy has shown promising results for scatter correction in cone‐beam computed tomography (CBCT). Different parameters of the system design affect its performance in scatter estimation and image reconstruction accuracy. The goal of this work is to optimize the geometric design of the moving block system.Methods:In the moving blocker system, a blocker consisting of lead strips is inserted between the x‐ray source and imaging object and moving back and forth along rotation axis during CBCT acquisition. CT image of an anthropomorphic pelvic phantom was used in the simulation study. Scatter signal was simulated by Monte Carlo calculation with various combinations of the lead strip width and the gap between neighboring lead strips, ranging from 4 mm to 80 mm (projected at the detector plane). Scatter signal in the unblocked region was estimated by cubic B‐spline interpolation from the blocked region. Scatter estimation accuracy was quantified as relative root mean squared error by comparing the interpolated scatter to the Monte Carlo simulated scatter. CBCT was reconstructed by total variation minimization from the unblocked region, under various combinations of the lead strip width and gap. Reconstruction accuracy in each condition is quantified by CT number error as comparing to a CBCT reconstructed from unblocked full projection data.Results:Scatter estimation error varied from 0.5% to 2.6% as the lead strip width and the gap varied from 4mm to 80mm. CT number error in the reconstructed CBCT images varied from 12 to 44. Highest reconstruction accuracy is achieved when the blocker lead strip width is 8 mm and the gap is 48 mm.Conclusions:Accurate scatter estimation can be achieved in large range of combinations of lead strip width and gap. However, image reconstruction accuracy is greatly affected by the geometry design of the blocker.
SU‐E‐E‐01: ABR Diagnostic Radiology Core Exam: Was Our Redesigned Physics Course Successful in Teaching Physics to Radiology Residents?
Authors: Kanal K , Hoff M , Dickinson R , Zamora D , Stewart B 
Published: July 2014

Purpose:Our purpose is to evaluate the effectiveness of our two year physics course in preparing radiology residents for the American Board of Radiology (ABR) diagnostic radiology exam.Methods:We designed a new two‐year physics course that integrates radiology clinical content and practice and is primarily based on the AAPM curriculum and RSNA/AAPM physics modules. Biweekly classes focus on relevant concepts from assigned reading and use audience response systems to encourage participation. Teaching efficiency is optimized through lecturer rotations of physicists, radiologists, and guest speakers. An emphasis is placed on clinical relevance by requiring lab work and providing equipment demonstrations. Periodic quiz were given during the course. The course website was also redesigned for usability, and physics review lectures were conducted two weeks before the board exam to refresh key concepts. At the completion of our first two‐year course, we conducted a confidential evaluation of the faculty and course. The evaluation assessed metrics such as overall organization, clinical relevance of content, and level of difficulty, with a rating scale from poor to excellent.Results:Our evaluation indicated that the redesigned course provided effective board exam preparation, with most responses between good and excellent. There was some criticism on the course length and on chronological discontinuity, but the review lectures were appreciated by the residents. All of our residents passed the physics component of the ABR exam with scores exceeding the minimum passing score by a significant margin.Conclusion:The course evaluation and board exam results indicate that our new two‐year course format provides valuable board exam preparation. This is possible thanks to the time and effort taken by the physics faculty on ensuring the residents get quality physics education.
SU‐E‐E‐02: Dashboard for Tracking Physics Resident Progress
Authors: Becker SJ 
Published: July 2014

Purpose:Design a system to easily and securely track the progress of medical physics residents through their residency. Paper sign‐offs while offering a real signature are not easily updated or summarized. A resident or mentor needs to be able to quickly assess what the current assignments are, what are overdue, and whether the resident is on track to complete all the tasks in a timely fashion. An electronic version can accomplish all these goals.Methods:An electronic dashboard was created in excel to not only house the tasks and sign‐off but to succinctly summarize the residents progress. The first tab contains the dashboard which displays tables of the progress of the residents in each rotation, their current task, and overdue tasks. It also displays the last meetings with the residents, and timeline of important items, and a burn‐down chart of the remaining tasks. This are all tied to the data and current date which auto fills the tables. The second tab contains the data. This is comprised of lists of rotations and their associated tasks along with their due dates. A signature column was also created which is password protected but allows special subset users i.e. mentors to alter without using a password.Results:The dashboard has allowed residents to better track their progress and tells them what they should be working on. It has also allowed the mentors and the program director to rapid assess their progress.Conclusion:The dashboard is successful and has been created to allow easy addition and subtraction of required tasks as the residency evolves. The next step is to create a web app version of the excel sheet with logins.
SU‐E‐E‐05: Initial Experience On Physics Rotation of Radiological Residents
Authors: Zhang J , Williams D , DiSantis D , Hardy P , Oates M 
Published: July 2014

Purpose:The new ABR core exam integrates physics into clinical teaching, with an emphasis on understanding image quality, image artifacts, radiation dose and patient safety for each modality and/or sub‐specialty. Accordingly, physics training of radiological residents faces a challenge. A traditional teaching of physics through didactic lectures may not fully fulfill this goal. It is also difficult to incorporate physics teaching in clinical practice due to time constraints. A dedicated physics rotation may be a solution. This study is to evaluate a full week physics workshop developed for the first year radiological residents.Methods:The physics rotation took a full week. It included three major parts, introduction lectures, hand‐on experiences and observation of technologist operation. An introduction of basic concepts was given to each modality at the beginning. Hand‐on experiments were emphasized and took most of time. During hand‐on experiments, residents performed radiation measurements, studied the relationship between patient dose and practice (i.e., fluoroscopy), investigated influence of acquisition parameters (i.g., kV, mAs) on image quality, and evaluated image quality using phantoms A physics test before and after the workshop was also given but not for comparison purpose.Results:The evaluation shows that the physics rotation during the first week of residency in radiology is preferred by all residents. The length of a full week of physics workshop is appropriate. All residents think that the intensive workshop can significantly benefit their coming clinical rotations. Residents become more comfortable regarding the use of radiation and counseling relevant questions such as a pregnant patient risk from a CE PE examination.Conclusion:A dedicated physics rotation, assisting with didactic lectures, may fulfill the requirements of physics of the new ABR core exam. It helps radiologists deeply understand the physics concepts and more efficiently use the medical physics in practice.
SU‐E‐P‐02: Imaging and Radiation Oncology Core (IROC) Houston QA Center (RPC) Credentialing
Authors: Amador C , Keith T , Nguyen T , Molineu A , Followill D 
Published: July 2014

Purpose:To provide information pertaining to IROC Houston QA Center's (RPC) credentialing process for institutions participating in NCI‐sponsored clinical trials.Methods:IROC Houston issues credentials for NCI sponsored study groups. Requirements for credentialing might include any combination of questionnaires, knowledge assessment forms, benchmarks, or phantom irradiations. Credentialing requirements for specific protocols can be found on IROC Houston's website (irochouston.mdanderson.org). The website also houses the credentialing status inquiry (CSI) form. Once an institution has reviewed the protocol's credentialing requirements, a CSI form should be completed and submitted to IROC Houston. This form is used both to request whether requirements have been met as well as to notify IROC Houston that the institution requests credentialing for a specific protocol. IROC Houston will contact the institution to discuss any delinquent requirements. Once the institution has met all requirements IROC Houston issues a credentialing letter to the institution and will inform study groups and other IROC offices of the credentials. Institutions can all phone the IROC Houston office to initiate credentialing or ask any credentialing related questions.Results:Since 2010 IROC has received 1313 credentialing status inquiry forms. We received 317 in 2010, 266 in 2011, 324 in 2012, and 406 in 2013. On average we receive 35 phone calls per week with multiple types of credentialing questions. Decisions regarding credentialing status are based on the protocol specifications and previous completed credentialing by the institution. In some cases, such as for general IMRT credentialing, up to 5 sites may be credentialed based on the credentialing of one main center. Each of these situations is handled individually.Conclusion:IROC Houston will issue radiation therapy credentials for the NCI trials in the National Clinical Trials Network. Credentialing requirements and the CSI form can be found online at the IROC Houston's website.Work supported by PHS grant CA10953 and CA081647 (NCI, DHHS).
SU‐E‐P‐03: Implementing a Low Dose Lung Screening CT Program Meeting Regulatory Requirements
Authors: LaFrance M , Marsh S , O' Donnell G 
Published: July 2014

Purpose:To provide information pertaining to IROC Houston QA Center's (RPC) credentialing process for institutions participating in NCI‐sponsored clinical trials.Purpose:Provide guidance to the Radiology Departments with the intent of implementing a Low Dose CT Screening Program using different CT Scanners with multiple techniques within the framework of the required state regulations.Method:State Requirements for the purpose of implementing a Low Dose CT Lung Protocol required working with the Radiology and Pulmonary Department in setting up a Low Dose Screening Protocol designed to reduce the radiation burden to the patients enrolled. Radiation dose measurements (CTDIvol) for various CT manufacturers (Siemens16, Siemens 64, Philips 64, and Neusoft128) for three different weight based protocols. All scans were reviewed by the Radiologist. Prior to starting a low dose lung screening protocol, information had to be submitted to the state for approval. Performing a Healing Arts protocol requires extensive information. This not only includes name and address of the applicant but a detailed description of the disease, the x‐ray examination and the population to be examined. The unit had to be tested by a qualified expert using the technique charts. The credentials of all the operators, the supervisors and the Radiologists had to be submitted to the state.Results:All the appropriate documentation was sent to the state for review. The measured results between the Low Dose Protocol versus the default Adult Chest Protocol showed that there was a dose reduction of 65% for small (100‐150 lb.) patient, 75% for the Medium patient (151‐250 lbs.), and a 55% reduction for the Large patient (over 250 lbs.).Conclusion:Measured results indicated that the Low Dose Protocol indeed lowered the screening patient's radiation dose and the institution was able to submit the protocol to the State's regulators.
SU‐E‐P‐07: Evaluation of Productivity Systems for Radiation Therapy
Authors: Ramsey C , Usynin A 
Published: July 2014

Purpose:Health systems throughout the United States are under increased financial pressure to reduce operating cost. As a result, productivity models developed by third‐party consultants are being used to optimize staff to treatment volumes. The purpose of this study was to critically evaluate productivity systems for radiation oncology.Methods:Staffing efficiency was evaluated using multiple productivity models. The first model evaluated staffing levels using equal weighting of procedure codes and hours worked. A second productivity model was developed using hours worked by job class and relative value units for each procedure code. A third model was developed using the measured procedure times extracted from the electronic medical record, which tracks the wait and treatment times for each patient for each treatment fraction. A MatLab program was developed to query and analyze the daily treatment data. A model was then created to determine any theoretical gains in treatment productivity.Results:Productivity was evaluated for six radiation therapy departments operating nine linear accelerators delivering over 40,000 treatment fractions per year. Third party productivity models that do not take into consideration the unique nature of radiation therapy can be counterproductive. For example, other outpatient departments can compress their daily schedule to decrease the worked hours. This approach was tested using the treatment schedule evaluation tool developed as part of this study. It was determined that the maximum possible savings for treatment schedule compression was $32,000 per year per linac. All annual cost savings would be lost if only two patients per year choose to be treated elsewhere because of limited or restricted appointment times.Conclusion:The use of productivity models in radiation therapy can easily result in a loss of treatment revenue that is greater than any potential cost savings in reduced hours worked by staff.
SU‐E‐P‐08: Alarming Range of Seed Activities Ordered for I‐125 Plaque Brachytherapy
Authors: Merz B 
Published: July 2014

Purpose:To investigate the variation in I‐125 seed activities ordered by various clinics for their plaque brachytherapy cases under a standardized set of assumptions.Methods:A majority of the plaque programs in North America were contacted and a survey was designed to give a few standardized cases to allow inter‐comparison of seed activities ordered. Tumor dose, treatment duration, number of seeds, plaque, and tumor apex were held constant in order to reveal differences in prescription point, seed type, and seed activity.Results:While the survey is presently underway, preliminary results show alarmingly wide variations between centers. Differences up to 45% have been found with 15% differences being common.Conclusion:Though knowledge of the TG‐43 dose calculation formalism is common, a number of factors in the field of plaque brachytherapy lead to alarming differences in activity of I‐125 seeds being ordered for a given tumor. Knowledge of the present reality of widely varying treatment activities, and thus doses to tumor and normal structures, should serve as motivation for centers involved in this modality to review their programs with others in the community and share their experiences.
SU‐E‐I‐02: A Framework to Perform Batch Simulations of Computational Voxel Phantoms to Study Organ Doses in Computed Tomography Using a Commercial Monte Carlo Software Package
Authors: Bujila R , Nowik P , Poludniowski G 
Published: July 2014

Purpose:ImpactMC (CT Imaging, Erlangen, Germany) is a Monte Carlo (MC) software package that offers a GPU enabled, user definable and validated method for 3D dose distribution calculations for radiography and Computed Tomography (CT). ImpactMC, in and of itself, offers limited capabilities to perform batch simulations. The aim of this work was to develop a framework for the batch simulation of absorbed organ dose distributions from CT scans of computational voxel phantoms.Methods:The ICRP 110 adult Reference Male and Reference Female computational voxel phantoms were formatted into compatible input volumes for MC simulations. A Matlab (The MathWorks Inc., Natick, MA) script was written to loop through a user defined set of simulation parameters and 1) generate input files required for the simulation, 2) start the MC simulation, 3) segment the absorbed dose for organs in the simulated dose volume and 4) transfer the organ doses to a database. A demonstration of the framework is made where the glandular breast dose to the adult Reference Female phantom, for a typical Chest CT examination, is investigated.Results:A batch of 48 contiguous simulations was performed with variations in the total collimation and spiral pitch. The demonstration of the framework showed that the glandular dose to the right and left breast will vary depending on the start angle of rotation, total collimation and spiral pitch.Conclusion:The developed framework provides a robust and efficient approach to performing a large number of user defined MC simulations with computational voxel phantoms in CT (minimal user interaction). The resulting organ doses from each simulation can be accessed through a database which greatly increases the ease of analyzing the resulting organ doses. The framework developed in this work provides a valuable resource when investigating different dose optimization strategies in CT.