bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐F‐SPS‐11: The Dosimetric Comparison of Truebeam 2.0 and Cyberknife M6 Treatment Plans for Brain SRS Treatment
Authors: Mabhouti H , Sanli E , Cebe M , Codel G , Pacaci P , Serin E , Kucuk N , Kucukmorkoc E , Doyuran M , Canoglu D , Altinok A , Acar H , Caglar Ozkok H 
Published: July 2016

Purpose:Brain stereotactic radiosurgery involves the use of precisely directed, single session radiation to create a desired radiobiologic response within the brain target with acceptable minimal effects on surrounding structures or tissues. In this study, the dosimetric comparison of Truebeam 2.0 and Cyberknife M6 treatment plans were made.Methods:For Truebeam 2.0 machine, treatment planning were done using 2 full arc VMAT technique with 6 FFF beam on the CT scan of Randophantom simulating the treatment of sterotactic treatments for one brain metastasis. The dose distribution were calculated using Eclipse treatment planning system with Acuros XB algorithm. The treatment planning of the same target were also done for Cyberknife M6 machine with Multiplan treatment planning system using Monte Carlo algorithm. Using the same film batch, the net OD to dose calibration curve was obtained using both machine by delivering 0‐ 800 cGy. Films were scanned 48 hours after irradiation using an Epson 1000XL flatbed scanner. Dose distribution were measured using EBT3 film dosimeter. The measured and calculated doses were compared.Results:The dose distribution in the target and 2 cm beyond the target edge were calculated on TPSs and measured using EBT3 film. For cyberknife plans, the gamma analysis passing rates between measured and calculated dose distributions were 99.2% and 96.7% for target and peripheral region of target respectively. For Truebeam plans, the gamma analysis passing rates were 99.1% and 95.5% for target and peripheral region of target respectively.Conclusion:Although, target dose distribution calculated accurately by Acuros XB and Monte Carlo algorithms, Monte carlo calculation algorithm predicts dose distribution around the peripheral region of target more accurately than Acuros algorithm.
SU‐F‐E‐01: Pitfalls: Reliability and Performance of Diagnostic X‐Sources
Authors: Behling R 
Published: July 2016

Purpose:Performance and reliability of medical X‐ray tubes for imaging are crucial from an ethical, clinical and economic perspective. This lecture will deliver insight into the aspects to consider during the decision making process to invest in X‐ray imaging equipment. Outdated metric still hampers realistic product comparison. It is time to change this and to comply with latest standards, which consider current technology. Failure modes and ways to avoid down‐time of the equipment shall be discussed. In view of the increasing number of interventional procedures and the hazards associated with ionizing radiation, toxic contrast agents, and the combination thereof, the aspect of system reliability is of paramount importance.Methods:A comprehensive picture of trends for different modalities (CT, angiography, general radiology) has been drawn and led to the development of novel X‐ray tube technology.Results:Recent X‐ray tubes feature enhanced reliability and unprecedented performance. Relevant metrics for product comparison still have to be implemented in practice.Conclusion:The speed of scientific and industrial development of new diagnostic and therapeutic X‐ray sources remains tremendous. Still, users suffer from gaps between desire and reality in day‐to‐day diagnostic routine. X‐ray sources are still limiting cutting‐edge medical procedures. Side‐effects of wear and tear, limitations of the clinical work flow, costs, the characteristics of the X‐ray spectrum and others topics need to be further addressed. New applications and modalities, like detection‐based color‐resolved X‐ray and phase‐contrast / dark‐field imaging will impact the course of new developments of X‐ray sources.The author is employee of Royal Philips
SU‐F‐E‐03: PET/CT Guided Dose Boost to Hypoxic Sub‐Volume in Nasopharyngeal Carcinomas Using Self‐Optimizing Non‐Uniform VMAT
Authors: Qiu J , Zheng X , Liu H , Chen B , Zhuo W 
Published: July 2016

Purpose:This study is to evaluate the feasibility of simultaneously integrated boost (SIB) to hypoxic subvolume (HTV) in nasopharyngeal carcinomas under the guidance of 18F‐Fluoromisonidazole (FMISO) PET/CT using a novel non‐uniform volumetric modulated arc therapy (VMAT)technique.Methods:Eight nasopharyngeal carcinoma patients treated with conventional uniform VMAT were retrospectively analyzed. For each treatment, actual conventional uniform VMAT plan with two or more arcs (2–2.5 arcs, totally rotating angle < 1000o) was designed with dose boost to hopxic subvolume (total dose, 84Gy) in the gross tumor volme (GTV) under the guidance of 18F‐ FMISO PET/CT. Based on the same dataset, experimental single arc non‐uniform VAMT plans were generated with the same dose prescription using customized software tools. Dosimetric parameters, quality assurance and the efficiency of the treatment delivery were compared between the uniform and non‐uniform VMAT plans.Results:To develop the non‐uniform VMAT technique, a specific optimization model was successfully established. Both techniques generate high‐quality plans with pass rate (>98%) with the 3mm, 3% criterion. HTV received dose of 84.1±0.75Gy and 84.1±1.2Gy from uniform and non‐uniform VMAT plans, respectively. In terms of target coverage and dose homogeneity, there was no significant statistical difference between actual and experimental plans for each case. However, for critical organs at risk (OAR), including the parotids, oral cavity and larynx, dosimetric difference was significant with better dose sparing form experimental plans. Regarding plan implementation efficiency, the average machine time was 3.5 minutes for the actual VMAT plans and 3.7 minutes for the experimental nonuniform VMAT plans (p>0.050).Conclusion:Compared to conventional VMAT technique, the proposed non‐uniform VMAT technique has the potential to produce efficient and safe treatment plans, especially in cases with complicated anatomical structures and demanding dose boost to subvolumes.
SU‐F‐E‐05: Determination of Breakeven Points of in Vitro Meats and in Vivo Mice Based On Tissue Temperature Enhancement Pattern
Authors: Austerlitz C , Barros A , Gkigkitzis I , Haranas I , Zhu D , Campos D 
Published: July 2016

Purpose:To determine the breakeven points in fresh commercial meat and in vivo mice using the tissue temperature enhancement pattern.Methods:A 1 cm length and 0.1 cm diameter gold rod were implanted in fresh chicken breast, beef, fish, in vivo Mus Musculus white mice (medial dorsal region) and insonated with ultrasound. The temperature enhancement of gold rods was measured with a needle type thermistor over a temperature range from 35–50 oC. From these results the breakeven points were determined by plotting the gold rod temperature versus ultrasound exposure time and determining the interception point of two curves fitted by a linear regression of thermal response above and below 43 °C.Results:The linear correlation coefficients for all fitted curves lie within 0.97 and 0.99. The breakeven points were found to be the same for all kinds of fresh meat (fish = 42.1 ±1.1, chicken breast = 42.3 ±0.9, beef = 42.6 ±0.8) and in vivo Mus Musculus white mice (43.3 ±0.6). These temperatures agree with the standardized value (e.g. equivalent minutes at 43 °C) for comparison of thermal treatments (Proc. SPIE Int. Soc. Opt. Eng. 2003 June 2; 4954: 37).Conclusion:The interception of the thermal response curves above and below 43 °C may be used as a fast method and useful dosimetric tool in clinical research.
SU‐F‐E‐08: Medical Physics as a Teaching Tool for High School Science Curriculum
Authors: Buckley L 
Published: July 2016

Purpose:Delivering high school science curriculum in a timely manner and in way that is accessible to all students is a challenge for teachers. Although many high schools offer career workshops, these are typically directed at senior students and do not relate directly to details of the curriculum. The objective of this initiative was to create a series of lectures that use medical physics to relate many aspects of the high school science curriculum to tangible clinical applications and to introduce students to alternate pathways into a career in health sciences.Methods:A series of lectures has been developed based on the Ontario High School Science Curriculum. Each lecture uses a career in radiotherapy medical physics as the framework for discussion of topics specific to the high school course being addressed.Results:At present, these lectures have been delivered in five area high schools to students ranging from sophomores to seniors. Survey documents are given to the students before and after the lecture to assess their awareness of careers in health care, applications of physics and their general interest in the subject areas. As expected, students have limited up front awareness of the wide variety of health related career paths. The idea of combining a career lecture with topics specific to the classroom curriculum has been well‐received by teachers and students alike.Conclusion:Career talks for high school students are useful for students contemplating their post‐ secondary career path. Relating career discussion with direct course curriculum makes their studies more relevant and engaging. Students aspiring to a career in health sciences often focus their studies on life sciences due to limited knowledge of potential careers. An early introduction to medical physics presents them with an alternate path through the physical sciences into health care.
SU‐F‐E‐15: Initial Experience Implementing a Case Method Teaching Approach to Radiation Oncology Physics Residents, Graduate Students and Doctorate of Medical Physics Students
Authors: Gutierrez A 
Published: July 2016

Purpose:Case Method Teaching approach is a teaching tool used commonly in business school to challenge students with real‐world situations—i.e. cases. The students are placed in the role of the decision maker and have to provide a solution based on the multitude of information provided. Specifically, students must develop an ability to quickly make sense of a complex problem, provide a solution incorporating all of the objectives (at time conflicting) and constraints, and communicate that solution in a succinct, professional and effective manner. The validity of the solution is highly dependent on the auxiliary information provided in the case and the basic didactic knowledge of the student. A Case Method Teaching approach was developed and implemented into an on‐going course focused on AAPM Task Group reports at UTHSCSA.Methods:A current course at UTHSCSA reviews and discusses 15 AAPM Task Group reports per semester. The course is structured into three topic modules: Imaging QA, Stereotactic Radiotherapy, and Special Patient Measurements—i.e. pacemakers, fetal dose. After a topic module is complete, the students are divided into groups (2–3 people) and are asked to review a case study related to the module topic. Students then provide a solution presented in an executive summary and class presentation.Results:Case studies were created to address each module topic. Through team work and whole‐class discussion, a collaborative learning environment was established. Students additionally learned concepts such vendor relations, financial negotiations, capital project management, and competitive strategy.Conclusion:Case Method Teaching approach is an effective teaching tool to further enhance the learning experience of radiation oncology physics students by presenting them with though‐provoking dilemmas that require students to distinguish pertinent from peripheral information, formulate strategies and recommendations for action, and confront obstacles to implementation.
SU‐F‐E‐16: A Specific Training Package for Medical Physicists in Support to Nuclear and Radiological Emergency Situations
Authors: Meghzifene A , Berris T 
Published: July 2016

Purpose:To provide the professional medical physicists with adequate competencies and skills in order to help them get prepared to support Nuclear or Radiological Emergency (NRE) situations.Methods:Although clinical medical physicists working have in‐depth knowledge in radiation dosimetry, including dose reconstruction and dose measurements, they are usually not involved in NRE situations. However, in a few instances where medical physicists were involved in NREs, it appeared that many lacked specific knowledge and skills that are required in such situations. This lack of specific knowledge and skills is probably due to the fact that most current medical physics curricula do not include a specific module on this topic. As a response to this finding, the IAEA decided to initiate a project to develop a specific training package to help prepare medical physicists to support NRE situations. The training package was developed with the kind support of the Government of Japan and in collaboration with Fukushima Medical University (FMU) and the National Institute of Radiological Sciences (NIRS).Results:The first International Workshop to test the training package was held in Fukushima, Japan in June 2015. It consisted of lectures, demonstrations, simulation, role play, and practical sessions followed by discussions. The training was delivered through 14 modules which were prepared with the support of 12 lecturers. A knowledge assessment test was done before the workshop, followed by the same test done at the end of the Workshop, to assess the knowledge acquired during the training.Conclusion:The Workshop was successfully implemented. The overall rating of the workshop by the participants was excellent and all participants reported that they acquired a good understanding of the main issues that are relevant to medical physics support in case of NRE situations. They are expected to disseminate the knowledge to other medical physicists in their countries.
SU‐F‐E‐18: Training Monthly QA of Medical Accelerators: Illustrated Instructions for Self‐Learning
Authors: Court L , Brown D , Wang H , Maddox B , Aten D , MacGregor H , Chi P , Yock A , Gao S , Aristophanous M , Balter P 
Published: July 2016

Purpose:To develop and test clear illustrated instructions for training of monthly mechanical QA of medical linear accelerators.Methods:Illustrated instructions were created for monthly mechanical QA with tolerance tabulated, and underwent several steps of review and refinement. Testers with zero QA experience were then recruited from our radiotherapy department (1 student, 2 computational scientists and 8 dosimetrists). The following parameters were progressively de‐calibrated on a Varian C‐series linac: Group A = gantry angle, ceiling laser position, X1 jaw position, couch longitudinal position, physical graticule position (5 testers); Group B = Group A + wall laser position, couch lateral and vertical position, collimator angle (3 testers); Group C = Group B + couch angle, wall laser angle, and optical distance indicator (3 testers). Testers were taught how to use the linac, and then used the instructions to try to identify these errors. A physicist observed each session, giving support on machine operation, as necessary. The instructions were further tested with groups of therapists, graduate students and physics residents at multiple institutions. We have also changed the language of the instructions to simulate using the instructions with non‐English speakers.Results:Testers were able to follow the instructions. They determined gantry, collimator and couch angle errors within 0.4, 0.3, and 0.9degrees of the actual changed values, respectively. Laser positions were determined within 1mm, and jaw positions within 2mm. Couch position errors were determined within 2 and 3mm for lateral/longitudinal and vertical errors, respectively. Accessory positioning errors were determined within 1mm. ODI errors were determined within 2mm when comparing with distance sticks, and 6mm when using blocks, indicating that distance sticks should be the preferred approach for inexperienced staff.Conclusion:Inexperienced users were able to follow these instructions, and catch errors within the criteria suggested by AAPM TG142 for linacs used for IMRT.
SU‐F‐E‐19: A Novel Method for TrueBeam Jaw Calibration
Authors: Corns R , Zhao Y , Huang V 
Published: July 2016

Purpose:A simple jaw calibration method is proposed for Varian TrueBeam using an EPID‐Encoder combination that gives accurate fields sizes and a homogeneous junction dose. This benefits clinical applications such as mono‐isocentric half‐beam block breast cancer or head and neck cancer treatment with junction/field matching.Methods:We use EPID imager with pixel size 0.392 mm × 0.392 mm to determine the radiation jaw position as measured from radio‐opaque markers aligned with the crosshair. We acquire two images with different symmetric field sizes and record each individual jaw encoder values. A linear relationship between each jaw's position and its encoder value is established, from which we predict the encoder values that produce the jaw positions required by TrueBeam's calibration procedure. During TrueBeam's jaw calibration procedure, we move the jaw with the pendant to set the jaw into position using the predicted encoder value. The overall accuracy is under 0.1 mm.Results:Our in‐house software analyses images and provides sub‐pixel accuracy to determine field centre and radiation edges (50% dose of the profile). We verified the TrueBeam encoder provides a reliable linear relationship for each individual jaw position (R2>0.9999) from which the encoder values necessary to set jaw calibration points (1 cm and 19 cm) are predicted. Junction matching dose inhomogeneities were improved from >±20% to <±6% using this new calibration protocol. However, one technical challenge exists for junction matching, if the collimator walkout is large.Conclusion:Our new TrueBeam jaw calibration method can systematically calibrate the jaws to crosshair within sub‐pixel accuracy and provides both good junction doses and field sizes. This method does not compensate for a larger collimator walkout, but can be used as the underlying foundation for addressing the walkout issue.
SU‐F‐E‐20: A Mathematical Model of Linac Jaw Calibration Integrated with Collimator Walkout
Authors: Zhao Y , Corns R , Huang V 
Published: July 2016

Purpose:Accurate jaw calibration is possible, but it does not necessarily achieve good junctions because of collimator rotation walkout. We developed a mathematical model seeking to pick an origin for calibration that minimizes the collimator walkout effect.Methods:We use radioopaque markers aligned with crosshair on the EPID to determine the collimator walkout at collimator angles 0°, 90° and 270°. We can accurately calibrate jaws to any arbitrary origin near the radiation field centre. While the absolute position of an origin moves with the collimator walkout, its relative location to the crosshair is an invariant. We studied two approaches to select an optimal origin. One approach seeks to bring all three origin locations (0°–90°–270°) as close as possible by minimizing the perimeter of the triangle formed by these points. The other approach focuses on the gap for 0°–90° junctions.Results:Our perimeter cost function has two variables and non‐linear behaviour. Generally, it does not have zero‐perimeter‐length solution which leads to perfect jaw matches. The zero solution can only be achieved, if the collimator rotates about a single fixed axis. In the second approach, we can always get perfect 0°–0° and 0°–90° junctions, because we ignore the 0°–270° situation. For our TrueBeams, both techniques for selecting an origin improved junction dose inhomogeneities to less than ±6%.Conclusion:Our model considers the general jaw matching with collimator rotations and proposes two potential solutions. One solution optimizes the junction gaps by considering all three collimator angles while the other only considers 0°–90°. The first solution will not give perfect matching, but can be clinically acceptable with minimized collimator walkout effect, while the second can have perfect junctions at the expense of the 0°–270° junctions. Different clinics might choose between these two methods basing on their clinical practices.
SU‐F‐P‐05: Initial Experience with an Independent Certification Program for Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy
Authors: Solberg T , Robar J , Gevaert T , Todorovic M , Howe J 
Published: July 2016

Purpose:The ASTRO document “Safety is no accident: A FRAMEWORK FOR QUALITY RADIATION ONCOLOGY AND CARE” recommends external reviews of specialized modalities. The purpose of this presentation is to describe the implementation of such a program for Stereotactic Radiosurgery (SRS) and Stereotactic Body radiation Therapy (SBRT).Methods:The margin of error for SRS and SBRT delivery is significantly smaller than that of conventional radiotherapy and therefore requires special attention and diligence. The Novalis Certified program was created to fill an unmet need for specialized SRS / SBRT credentialing. A standards document was drafted by a panel of experts from several disciplines, including medical physics, radiation oncology and neurosurgery. The document, based on national and international standards, covers requirements in program structure, personnel, training, clinical application, technology, quality management, and patient and equipment QA. The credentialing process was modeled after existing certification programs and includes an institution‐generated self‐study, extensive document review and an onsite audit. Reviewers generate a descriptive report, which is reviewed by a multidisciplinary expert panel. Outcomes of the review may include mandatory requirements and optional recommendations.Results:15 institutions have received Novalis Certification, including 3 in the US, 7 in Europe, 4 in Australia and 1 in Asia. 87 other centers are at various stages of the process. Nine reviews have resulted in mandatory requirements, however all of these were addressed within three months of the audit report. All reviews have produced specific recommendations ranging from programmatic to technical in nature. Institutions felt that the credentialing process addressed a critical need and was highly valuable to the institution.Conclusion:Novalis Certification is a unique peer review program assessing safety and quality in SRS and SBRT, while recognizing international practice standards. The approach is capable of highlighting outstanding requirements and providing recommendations to enhance both new and established programs.Timothy Solberg is co‐owner of Global Radiosurgery services, LLC