bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐D‐201‐01: Attenuation of PET/CT Gantries with 511 KeV Photons
Authors: Busse N 
Published: June 2015

Purpose:PET shielding requires the use of large amounts of lead because of the penetrating nature of 511 keV photons. While the uptake rooms generally require the thickest lead, the scan room often requires substantial shielding. Attenuation by the PET/CT gantry is normally assumed to be zero, but may be significant in directions perpendicular to the scanner axis.Methods:A 5 mL tube was filled with between 14.7 and 20.5 mCi of F‐18 and inserted into a phantom (70 cm NEMA PET Scatter Phantom). Exposure rates were recorded at several distances and 15° intervals with a pressurized ionization chamber (Ludlum 9DP) both with the phantom outside the gantry and centered in the CT and PET acquisition positions. These measurements were repeated with three scanners: Siemens Biograph TruePoint 6, GE Optima 560, and Philips Gemini 64. Measurements were decay corrected and normalized to exposure rates outside the gantry to calculate percent transmission.Results:Between 45° to 135° (measured from the patient bed at 0°), average transmission was about 20% for GE, 35% for Philips, and 30% for Siemens. The CT gantry was roughly twice as attenuating as the PET gantry at 90° for all three manufacturers, with about 10% transmission through the CT gantry and 20% through the PET gantry.Conclusion:The Philips system is a split‐gantry and therefore has a narrower angle of substantial attenuation. For the GE and Siemens systems, which are single‐gantry design, transmission was relatively constant once the angle was sufficient to block line‐of‐sight from the phantom. While the patient may spend a greater fraction of time at the PET position of the scanner, transmission characteristics of the two components are similar enough to be treated collectively. For shielding angles between 45° and 135°, a reasonably conservative assumption would be to assume gantry transmission of 50%.
SU‐D‐201‐07: Exploring the Utility of 4D FDG‐PET/CT Scans in Design of Radiation Therapy Planning Compared with 3D PET/CT: A Prospective Study
Authors: Ma C , Yin Y 
Published: June 2015

Purpose:A method using four‐dimensional(4D) PET/CT in design of radiation treatment planning was proposed and the target volume and radiation dose distribution changes relative to standard three‐dimensional (3D) PET/CT were examined.Methods:A target deformable registration method was used by which the whole patient's respiration process was considered and the effect of respiration motion was minimized when designing radiotherapy planning. The gross tumor volume of a non‐small‐cell lung cancer was contoured on the 4D FDG‐PET/CT and 3D PET/CT scans by use of two different techniques: manual contouring by an experienced radiation oncologist using a predetermined protocol; another technique using a constant threshold of standardized uptake value (SUV) greater than 2.5. The target volume and radiotherapy dose distribution between VOL3D and VOL4D were analyzed.Results:For all phases, the average automatic and manually GTV volume was 18.61 cm3 (range, 16.39–22.03 cm3) and 31.29 cm3 (range, 30.11–35.55 cm3), respectively. The automatic and manually volume of merged IGTV were 27.82 cm3 and 49.37 cm3, respectively. For the manual contour, compared to 3D plan the mean dose for the left, right, and total lung of 4D plan have an average decrease 21.55%, 15.17% and 15.86%, respectively. The maximum dose of spinal cord has an average decrease 2.35%. For the automatic contour, the mean dose for the left, right, and total lung have an average decrease 23.48%, 16.84% and 17.44%, respectively. The maximum dose of spinal cord has an average decrease 1.68%.Conclusion:In comparison to 3D PET/CT, 4D PET/CT may better define the extent of moving tumors and reduce the contouring tumor volume thereby optimize radiation treatment planning for lung tumors.
SU‐E‐E‐04: Assessment of Medical Physics Students and Trainees Interest and Awareness of Non‐Clinical Careers
Authors: Tanny S , Roth A , Peeler C , Rodrigues A , Ready J 
Published: June 2015

Purpose:The majority of medical physics education programs focus on preparing aspiring physicists for a career in the clinic, which could under‐represent non‐clinical opportunities in medical physics. Non‐clinical careers offer an opportunity to affect patient care on a worldwide scale, and increase the number of career options for graduating students. Our purpose is to evaluate the knowledge within the medical physics community of the opportunities available to aspiring physicists outside of the clinic.Methods:We have conducted a survey of current students and trainees’ and of physicists who joined the AAPM within the past 5 years. Respondents were asked to complete questions related to their knowledge and interest in non‐clinical careers. Practicing physicists were asked about the impact of non‐clinical careers in medical physics.Results:Over 150 students and 135 new physicists responded to our survey requests. 60% of students expressed that they did not feel knowledgeable concerning their non‐clinical options, whereas only 32% of recent graduates stated that they were unaware of non‐clinical opportunities. 68% of students expressed at least an intermediate interest in non‐clinical options. Of those interested, 54% of them did not feel knowledgeable of non‐clinical opportunities. Of the 110 respondents with intermediate or greater interest, 72%, 66%, 24% and 20% expressed interest to pursue opportunities in industry, academic research, health physics, and regulation, respectively. This was not reflected by the recent graduates, where only 43% of respondents considered a non‐clinical career path.Conclusions:A majority of current medical physics students surveyed expressed that they are under‐informed about non‐clinical career opportunities. Recent graduates indicated a higher level of awareness of non‐clinical options, but many chose not to consider them for their initial career placement. More work is needed from medical physics education programs to better inform students of non‐clinical options and how to prepare them.
SU‐E‐E‐09: The Novel Investigation of the Accuracy of Image Position for Liver During Respiration in Helical CT
Authors: Tsai Y , Yu P , Chang H , Chang C , Fu P , Lin C , Chiu Y , Chi S 
Published: June 2015

Purpose:To assess the image position of liver along the Z‐axis in helical CT compared to 4D CT and to evaluate the imaging similarity of helical CT and different phases of 4D CT for liver during respiration.Methods:Eleven patients with whole liver scanning during free breath in both helical CT and 4D CT were investigated. Eleven representative points ₍in liver segment 1, 2, 3, 4a, 4b, 5, 6, 7, 8, main portal vein, liver dome₎ were drew in helical CT image and adaptive deformed to 4D CT image, including the phase of end‐inspiration ₍phase 0₎ and end‐expiration ₍phase 50₎, using SmartAdapt in Eclipse™ version 11.5. Distances along the Z‐axis of the 11 points from helical CT to phase 0 CT, helical CT to phase 50 CT were measured, which represented the similarity of helical CT and end‐inspiration CT, helical CT and end‐expiration CT, respectively, for liver.Results:Mean distance along the Z‐axis from helical CT to phase 0 CT is ‐2.4±1.3 ₍mean±SD₎₍mm₎, which is the average of the 11 points ₍S1:‐2.5±4.6, S2:‐2.5±5.1, S3:‐4.0±3.2, S4a:‐0.9±4.4, S4b:‐2.9±4.1, S5:‐2.0±2.5, S6:‐3.6±3.3, S7:‐3.6±4.3, S8:‐1.8±3.9, main portal vein:‐3.4±4.1, liver dome:0.3±4.1₎. Mean distance from helical CT to phase 50 CT is 3.9±1.6 ₍S1:3.0±4.2, S2:3.2±3.8, S3:2.1±1.9, S4a:1.4±3.6, S4b:3.7±3.9, S5:3.7±2.7, S6:3.9±3.3, S7:6.0±5.0, S8:3.7±3.8, main portal vein:4.8±4.8, liver dome:7.1±5.9₎.Conclusion:Surprisingly, the image of helical CT scanning at random during free breath is more similar to the image at end‐inspiration, which is not corresponding to human physiology. Moreover, the helical CT image at liver dome is even beyond the image at end‐inspiration.
SU‐E‐E‐10: Statistical Process Control for VMAT Pre‐Treatment Verification QA Using ArcCHECK and Mobius3D
Authors: Alani S , Schlocker A , Honig N 
Published: June 2015

Purpose:Process capability indices (PCI) are intended to provide single number assessment of ability to meet specification limits on quality characteristics of interest. It can be deduced from the multiple literature citations that PCI are both an effective and excellent means of measuring quality and performance, and have been widely used in the manufacturing industry. This work applied PCI to establish the control limits of the gamma analysis pass rate percentage for patient specific volumetric modulated arc therapy (VMAT) quality assurance (QA), and to evaluate the efficiency of the QA process by using the process capability performance measurement index (Cpm).Methods:335 QA plans were measured and evaluated with Mobius3D, a software designed to be an independent treatment plan evaluation tool, and ArcCHECK, a hardware/software product designed for measurement‐based patient‐specific plan QA analysis. The Γ‐(3%/3mm) criteria were used to evaluate the QA plans.Results:A statistical analysis of the Γ‐(3%/3mm) passing rates was performed. The Cpm calculated to evaluate QA the capabilities and suitability of the Mobius3D and ArcCHECK QA.The Cpm values of Mobius3D QA was 1.73 and ArcCHECK QA was 1.82 The average Γ‐(3%/3mm)pass was 96.2 +/−2.9 % for ArcCHECK and 95.3 +/−2.1 % for Mobius3D.Conclusion:Statistical process controls are useful to quantifiably demonstrate the QA process conformance to specifications. Systematic errors were greater with the ArcCHECK QA process than with the Mobius3D QA process. We speculate that this is due to the physical effort/manual intervention required to setup the ArcCHECK phantom for the measurements.Both the Mobius3D and ArcCHECK QA processes have proven to be acceptable because the values are higher than 1.0
SU‐E‐P‐01: Adaptation of Commercial, Web‐Based, Medical Residency Management Software (MedHub, Inc.) for a Medium‐Sized Medical Physics Residency Program
Authors: Medin P , Pompos A , Britton L , Foster R 
Published: June 2015

Purpose:Management of a CAMPEP‐accredited medical physics residency program (CaMPRP) is demanding. In our experience, the time required to manage a CaMPRP increased linearly with the number of residents. Managing our paper‐based CaMPRP became unwieldy and inefficient when we increased in size from three to four residents resulting in the purchase of commercial, web‐based residency management software (MedHub, Inc).Methods:All documentation for our CaMPRP was converted into a format that fits the MedHub structure including: all assessments, procedure participation, mentor/resident meeting summaries, director/resident meeting summaries, journals, tumor board and departmental meeting attendance, written reports, presentations, resident/faculty/staff evaluations, didactic coursework approval, licenses, absence tracking, and ethics/professionalism coursework. The conversion process was performed over a 4‐month period and required approximately 120 hours of director time and 100 hours of administrator time. Task assignments and documentation required of residents and faculty are now scheduled and dispersed through MedHub via email. Regular reminders are automatically emailed from MedHub for incomplete documentation. The MedHub server is maintained centrally by a university‐wide system administrator. Data is encrypted and meets FERPA and HIPAA standards.Results:MedHub is a repository for all documentation required of a CaMPRP and is viewable from supported internet browsers. Resident progress and compliance is transparent and viewable in real‐time by residents and administration. Resident and faculty compliance with required documentation and attendance have increased dramatically, approaching 100%. Management of our CaMPRP is now consistent with the medical residency programs who use Medhub campus‐wide. Anonymity is preserved for evaluations of personnel. Lost paper documentation is no longer a concern. Data mining tools are being created to analyze documentation to help increase focus and productivity.Conclusion:Medical residency management software has been successfully adapted by a CaMPRP. This management tool has been very useful toward increasing compliance, access, transparency, anonymity and productivity.
SU‐E‐P‐20: Personnel Lead Apparel Integrity Inspection: Where We Are and What We Need?
Authors: Smith S , Zhang J , Anaskevich L , Oates E 
Published: June 2015

Purpose:In recent years, tremendous efforts have been devoted to radiation dose reduction, especially for patients who are directly exposed to primary radiation or receive radiopharmaceuticals. Limited efforts have been focused on those personnel who are exposed to secondary radiation while fulfilling their work responsibilities associated with diagnostic imaging and image‐guided interventions. Occupational exposure is compounded in daily practice and can lead to a significant radiation dose over time. Personnel lead apparel is a well‐accepted engineering control to protect healthcare workers when radiation is inevitable. The question is, do we have a nationally established program to protect personnel? This study is to investigate the lead apparel inspection programs among the USA.Methods:A series of surveys of state regulations, the University Health System Consortium, and federal regulations and regulations determined by accrediting bodies were conducted. The surveys were used to determine the current status of lead apparel programs regarding integrity inspections. Based on the survey results, a thorough program was proposed accordingly.Results:Of 50 states, seventeen states and Washington D.C. require lead apparel integrity inspections within their state regulations. Eleven of these states specify that the inspection is required on an annual basis. Two of these states require lead apron integrity checks to be performed semi‐annually. Eleven out of the two hundred academic medical centers surveyed responded. The results show that the method (visually vs. fluoroscopy) used to conduct lead apparel integrity checks differ greatly amongst healthcare organizations. The FDA, EPA, CRCPD and NCRP require lead apparel integrity checks. However, the level of policies is different. A standard program is not well established and clearly there is a lack of standardization.Conclusion:A program led by legislative (state or federal government) and with specific frequency, methods, tracking and criteria is needed to ensure the integrity of personnel lead apparel.
SU‐E‐P‐21: Impact of MLC Position Errors On Simultaneous Integrated Boost Intensity‐Modulated Radiotherapy for Nasopharyngeal Carcinoma
Authors: Chengqiang L , Yin Y , Chen L 
Published: June 2015

Purpose:To investigate the impact of MLC position errors on simultaneous integrated boost intensity‐modulated radiotherapy (SIB‐IMRT) for patients with nasopharyngeal carcinoma.Methods:To compare the dosimetric differences between the simulated plans and the clinical plans, ten patients with locally advanced NPC treated with SIB‐IMRT were enrolled in this study. All plans were calculated with an inverse planning system (Pinnacle3, Philips Medical System₎. Random errors −2mm to 2mm₎,shift errors₍ 2mm,1mm and 0.5mm) and systematic extension/ contraction errors (±2mm, ±1mm and ±0.5mm) of the MLC leaf position were introduced respectively into the original plans to create the simulated plans. Dosimetry factors were compared between the original and the simulated plans.Results:The dosimetric impact of the random and system shift errors of MLC position was insignificant within 2mm, the maximum changes in D95% of PGTV,PTV1,PTV2 were‐0.92±0.51%,1.00±0.24% and 0.62±0.17%, the maximum changes in the D0.1cc of spinal cord and brainstem were 1.90±2.80% and −1.78±1.42%, the maximum changes in the Dmean of parotids were1.36±1.23% and −2.25±2.04%.However,the impact of MLC extension or contraction errors was found significant. For 2mm leaf extension errors, the average changes in D95% of PGTV,PTV1,PTV2 were 4.31±0.67%,4.29±0.65% and 4.79±0.82%, the averaged value of the D0.1cc to spinal cord and brainstem were increased by 7.39±5.25% and 6.32±2.28%,the averaged value of the mean dose to left and right parotid were increased by 12.75±2.02%,13.39±2.17% respectively.Conclusion:The dosimetric effect was insignificant for random MLC leaf position errors up to 2mm. There was a high sensitivity to dose distribution for MLC extension or contraction errors.We should pay attention to the anatomic changes in target organs and anatomical structures during the course,individual radiotherapy was recommended to ensure adaptive doses.
SU‐E‐P‐23: What Can the Medical Physics Field Learn From the Open Source Hardware Community?
Authors: Wootton L , Therriault‐Proulx F , Beddar S 
Published: June 2015

Purpose:To introduce the Medical Physics community to the up‐and‐coming open hardware movement, and discuss what lessons can be learned from it and how it could be useful to our field.Methods:By definition, open source hardware is “hardware whose design is made publicly available so that anyone can study, modify, distribute, make, and sell the design or hardware based on that design”. Arduino microcontroller boards and the evolution in 3d printing technologies are among the most successful open hardware examples. These examples showed that both collaboration and competition are factors facilitating and accelerating innovations. They also help universalizing research by decreasing costs and enabling higher‐level manufacturing. Participation in open source projects in academia has also shown to have multiple advantages. The project gets massively peer reviewed through its online publication, and the comments generally lead to improvement of the design and better performance. It also increases the visibility of the work, therefore increasing the chance for citations and funding.Results:The development in‐house of a motorized detector positioning device that can be mounted to a water tank will be open‐sourced and presented as an example of open source project that could be useful to others in the Medical Physics field, whether it is for research or clinical work. The common aspects to share when open‐sourcing a project will be discussed. A device for regulating the temperature inside a water phantom will also be presented and open‐sourced to the community. Finally, the development of a project‐sharing web platform specially designed for the Medical Physics community will be discussed.Conclusion:The open source hardware movement is gaining in popularity and the Medical Physics field could benefit from a similar collaborative open‐framework. It would definitely help driving and accelerating innovations in the field as well as decreasing some of the associated costs.Part of this research was supported by the Odyssey Program at The University of Texas MD Anderson Cancer Center.
SU‐E‐P‐27: Efficient Process for AccuBoost Planning and Treatment Delivery to Minimize Patient Compression Time
Authors: Iftimia I , Talmadge M , Halvorsen P 
Published: June 2015

Purpose:To implement an efficient and robust process for AccuBoost planning and treatment delivery that can be safely performed by a single Physicist while minimizing patient's total session time.Methods:Following a thorough commissioning and validation process, templates were created in the brachytherapy planning system for each AccuBoost applicator. Tables of individual and total nominal dwell times for each applicator as a function of separation were generated to streamline planning while an Excel‐based nomogram provided by the vendor functions as a secondary verification of the treatment parameters. Tables of surface dose as a function of separation and applicator, along with concise guidance documents for applicator selection, are readily available during the planning process. The entire process is described in a set of detailed Standard Operating Procedures which, in addition to the items described above, include a verbal time‐out between the primary planner and the individual performing the secondary verification as well as direct visual confirmation of applicator placement using an articulated mirror. Prior to treatment initiation, a final time‐out is conducted with the Radiation Oncologist. Chart documentation is finalized after the patient is released from compression following completion of the treatment.Results:With the aforementioned procedures, it has been possible to consistently limit the time required to prepare each treatment such that the patient is typically under compression for less than 10 minutes per orientation prior to the initiation of the treatment, which is particularly important for APBI cases. This process can be overseen by a single physicist assisted by a dosimetrist and has been optimized during the past 16 months, with 180 treatment sessions safely completed to date.Conclusion:This work demonstrates the implementation of an efficient and robust process for real‐time‐planned AccuBoost treatments that effectively minimizes the time that the patient is under compression.
SU‐E‐P‐28: Mammography System Collimation Assessment Using Unfors/RaySafe DXR+: How to Increase the Measurement Accuracy
Authors: Wang W , Erdi Y 
Published: June 2015

Purpose:Unfors DXR rulers (Hopkinton, MA) are used to measure the X‐ray field to light field coincidence for mammography systems with a small SID of approximately 66cm. However, due to its bulky size (14.5mm thick with 2.5mm sensors) thickness correction is needed.Methods:Unfors DXR rulers were used to evaluate the collimation of three mammography systems: GE Essential, GE 2000D, and Hologic Selenia with various compression paddles. When measuring the X‐ray field to light‐field coincidence using DXR rulers, the light‐field is aligned to the zero mark on top of the ruler which is 14.5mm from the base of the ruler, while the X‐ray sensor inside the ruler is at 7mm from the base of the ruler. Error occurs because of this 7.5mm difference. To resolve this problem, the error is projected to different reference planes for GE and Hologic mammography systems and the correction factors (CFs) are generated. In order to generate the CFs, the image size at the image receptor is measured/calculated for GE and Hologic mammography systems with various compression paddles using the images stored in PACS. For the shifting compression paddle, the movement is also measured at the image receptor plane and CFs are generated based on the X‐ray field locations.Results:The generated CFs were used to calculate the X‐ray field to light field coincidence. The CFs ranges from 1.0mm for Hologic Selenia with 18×24cm compression paddle to 2.9mm for GE Essential with 24×30.7cm compression paddle.Conclusion:CFs were generated for 3 mammography systems with various compression paddles when measuring the X‐ray field to light field coincidence using Unfors DXR rulers. The application of these correction factors adjusts the X‐ray field to light field misalignment calculation up to 0.55% of the SID which is over a quarter of the 2% SID pass/fail criteria for mammography systems.