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At least 397 records · Page 22
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DOE OSTI2012

Quality Assurance Peer Review Chart Rounds in 2011: A Survey of Academic Institutions in the United States

Purpose: In light of concerns regarding the quality of radiation treatment delivery, we surveyed the practice of quality assurance peer review chart rounds at American academic institutions. Methods and Materials: An anonymous web-based survey was sent to the chief resident of each institution across the United States. Results: The response rate was 80% (57/71). The median amount of time spent per patient was 2.7 minutes (range, 0.6-14.4). The mean attendance by senior physicians and residents was 73% and 93%, respectively. A physicist was consistently present at peer review rounds in 66% of departments. There was a close association between attendance by senior physicians and departmental organization: in departments with protected time policies, good attendance was 81% vs. 31% without protected time (p = 0.001), and in departments that documented attendance, attending presence was 69% vs. 29% in departments without documentation (p < 0.05). More than 80% of institutions peer review all external beam therapy courses; however, rates were much lower for other modalities (radiosurgery 58%, brachytherapy 40%-47%). Patient history, chart documentation, and dose prescription were always peer reviewed in >75% of institutions, whereas dosimetric details (beams, wedges), isodose coverage, intensity-modulated radiation therapy constraints, and dose-volume histograms were always peer reviewed in 63%, 59%, 42%, and 50% of cases, respectively. Chart rounds led to both minor (defined as a small multileaf collimator change/repeated port film) and major (change to dose prescription or replan with dosimetry) treatment changes. Whereas at the majority of institutions changes were rare (<10% of cases), 39% and 11% of institutions reported that minor and major changes, respectively, were made to more than 10% of cases. Conclusion: The implementation of peer review chart rounds seems inconsistent across American academic institutions. Brachytherapy and radiosurgical procedures are rarely reviewed. Attendance by senior physicians is variable, but it improves when scheduling clashes are avoided. The potential effect of a more thorough quality assurance peer review on patient outcomes is not known.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Quality Control Quantification (QCQ): A Tool to Measure the Value of Quality Control Checks in Radiation Oncology

Purpose: To quantify the error-detection effectiveness of commonly used quality control (QC) measures. Methods: We analyzed incidents from 2007-2010 logged into a voluntary in-house, electronic incident learning systems at 2 academic radiation oncology clinics. None of the incidents resulted in patient harm. Each incident was graded for potential severity using the French Nuclear Safety Authority scoring scale; high potential severity incidents (score >3) were considered, along with a subset of 30 randomly chosen low severity incidents. Each report was evaluated to identify which of 15 common QC checks could have detected it. The effectiveness was calculated, defined as the percentage of incidents that each QC measure could detect, both for individual QC checks and for combinations of checks. Results: In total, 4407 incidents were reported, 292 of which had high-potential severity. High- and low-severity incidents were detectable by 4.0 {+-} 2.3 (mean {+-} SD) and 2.6 {+-} 1.4 QC checks, respectively (P<.001). All individual checks were less than 50% sensitive with the exception of pretreatment plan review by a physicist (63%). An effectiveness of 97% was achieved with 7 checks used in combination and was not further improved with more checks. The combination of checks with the highest effectiveness includes physics plan review, physician plan review, Electronic Portal Imaging Device-based in vivo portal dosimetry, radiation therapist timeout, weekly physics chart check, the use of checklists, port films, and source-to-skin distance checks. Some commonly used QC checks such as pretreatment intensity modulated radiation therapy QA do not substantially add to the ability to detect errors in these data. Conclusions: The effectiveness of QC measures in radiation oncology depends sensitively on which checks are used and in which combinations. A small percentage of errors cannot be detected by any of the standard formal QC checks currently in broad use, suggesting that further improvements are needed. These data require confirmation with a broader incident-reporting database.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Proton: The Particle

The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10{sup 80}. Protons were created at 10{sup −6} –1 second after the Big Bang at ≈1.37 × 10{sup 10} years beforethe present. Proton life span has been experimentally determined to be ≥10{sup 34} years; that is, the age of the universe is 10{sup −24}th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W{sup +}, W{sup −}, Z{sup 0}, and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

On the Sensitivity of α/β Prediction to Dose Calculation Methodology in Prostate Brachytherapy

Purpose: To study the relationship between the accuracy of the dose calculation in brachytherapy and the estimations of the radiosensitivity parameter, α/β, for prostate cancer. Methods and Materials: In this study, Monte Carlo methods and more specifically the code ALGEBRA was used to produce accurate dose calculations in the case of prostate brachytherapy. Equivalent uniform biologically effective dose was calculated for these dose distributions and was used in an iso-effectiveness relationship with external beam radiation therapy. Results: By considering different levels of detail in the calculations, the estimation for the α/β parameter varied from 1.9 to 6.3 Gy, compared with a value of 3.0 Gy suggested by the American Association of Physicists in Medicine Task Group 137. Conclusions: Large variations of the α/β show the sensitivity of this parameter to dose calculation modality. The use of accurate dose calculation engines is critical for better evaluating the biological outcomes of treatments.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Practical Implementation of Failure Mode and Effects Analysis for Safety and Efficiency in Stereotactic Radiosurgery

Purpose: To improve the safety and efficiency of a new stereotactic radiosurgery program with the application of failure mode and effects analysis (FMEA) performed by a multidisciplinary team of health care professionals. Methods and Materials: Representatives included physicists, therapists, dosimetrists, oncologists, and administrators. A detailed process tree was created from an initial high-level process tree to facilitate the identification of possible failure modes. Group members were asked to determine failure modes that they considered to be the highest risk before scoring failure modes. Risk priority numbers (RPNs) were determined by each group member individually and then averaged. Results: A total of 99 failure modes were identified. The 5 failure modes with an RPN above 150 were further analyzed to attempt to reduce these RPNs. Only 1 of the initial items that the group presumed to be high-risk (magnetic resonance imaging laterality reversed) was ranked in these top 5 items. New process controls were put in place to reduce the severity, occurrence, and detectability scores for all of the top 5 failure modes. Conclusions: FMEA is a valuable team activity that can assist in the creation or restructuring of a quality assurance program with the aim of improved safety, quality, and efficiency. Performing the FMEA helped group members to see how they fit into the bigger picture of the program, and it served to reduce biases and preconceived notions about which elements of the program were the riskiest.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Novel Radiobiological Gamma Index for Evaluation of 3-Dimensional Predicted Dose Distribution

Purpose: To propose a gamma index-based dose evaluation index that integrates the radiobiological parameters of tumor control (TCP) and normal tissue complication probabilities (NTCP). Methods and Materials: Fifteen prostate and head and neck (H&N) cancer patients received intensity modulated radiation therapy. Before treatment, patient-specific quality assurance was conducted via beam-by-beam analysis, and beam-specific dose error distributions were generated. The predicted 3-dimensional (3D) dose distribution was calculated by back-projection of relative dose error distribution per beam. A 3D gamma analysis of different organs (prostate: clinical [CTV] and planned target volumes [PTV], rectum, bladder, femoral heads; H&N: gross tumor volume [GTV], CTV, spinal cord, brain stem, both parotids) was performed using predicted and planned dose distributions under 2%/2 mm tolerance and physical gamma passing rate was calculated. TCP and NTCP values were calculated for voxels with physical gamma indices (PGI) >1. We propose a new radiobiological gamma index (RGI) to quantify the radiobiological effects of TCP and NTCP and calculate radiobiological gamma passing rates. Results: The mean RGI gamma passing rates for prostate cases were significantly different compared with those of PGI (P<.03–.001). The mean RGI gamma passing rates for H&N cases (except for GTV) were significantly different compared with those of PGI (P<.001). Differences in gamma passing rates between PGI and RGI were due to dose differences between the planned and predicted dose distributions. Radiobiological gamma distribution was visualized to identify areas where the dose was radiobiologically important. Conclusions: RGI was proposed to integrate radiobiological effects into PGI. This index would assist physicians and medical physicists not only in physical evaluations of treatment delivery accuracy, but also in clinical evaluations of predicted dose distribution.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Technology for Innovation in Radiation Oncology

Radiation therapy is an effective, personalized cancer treatment that has benefited from technological advances associated with the growing ability to identify and target tumors with accuracy and precision. Given that these advances have played a central role in the success of radiation therapy as a major component of comprehensive cancer care, the American Society for Radiation Oncology (ASTRO), the American Association of Physicists in Medicine (AAPM), and the National Cancer Institute (NCI) sponsored a workshop entitled “Technology for Innovation in Radiation Oncology,” which took place at the National Institutes of Health (NIH) in Bethesda, Maryland, on June 13 and 14, 2013. The purpose of this workshop was to discuss emerging technology for the field and to recognize areas for greater research investment. Expert clinicians and scientists discussed innovative technology in radiation oncology, in particular as to how these technologies are being developed and translated to clinical practice in the face of current and future challenges and opportunities. Technologies encompassed topics in functional imaging, treatment devices, nanotechnology, and information technology. The technical, quality, and safety performance of these technologies were also considered. A major theme of the workshop was the growing importance of innovation in the domain of process automation and oncology informatics. The technologically advanced nature of radiation therapy treatments predisposes radiation oncology research teams to take on informatics research initiatives. In addition, the discussion on technology development was balanced with a parallel conversation regarding the need for evidence of efficacy and effectiveness. The linkage between the need for evidence and the efforts in informatics research was clearly identified as synergistic.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Education and Training Needs in Radiation Oncology in India: Opportunities for Indo–US Collaborations

Purpose: To conduct a survey of radiation oncologists in India, to better understand specific educational needs of radiation oncology in India and define areas of collaboration with US institutions. Methods and Materials: A 20-question survey was distributed to members of the Association of Indian Radiation Oncologists and the Indian Brachytherapy Society between November 2013 and May 2014. Results: We received a total of 132 responses. Over 50% of the physicians treat more than 200 patients per day, use 2-dimensional or 3-dimensional treatment planning techniques, and approximately 50% use image guided techniques. For education needs, most respondents agreed that further education in intensity modulated radiation therapy, image guided radiation therapy, stereotactic radiation therapy, biostatistics, and research methods for medical residents would be useful areas of collaboration with institutions in the United States. Other areas of collaboration include developing a structured training module for nursing, physics training, and developing a second-opinion clinic for difficult cases with faculty in the United States. Conclusion: Various areas of potential collaboration in radiation oncology education were identified through this survey. These include the following: establishing education programs focused on current technology, facilitating exchange programs for trainees in India to the United States, promoting training in research methods, establishing training modules for physicists and oncology nurses, and creating an Indo–US. Tumor Board. It would require collaboration between the Association of Indian Radiation Oncologists and the American Society for Radiation Oncology to develop these educational initiatives.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2016

Image Guided Cervical Brachytherapy: 2014 Survey of the American Brachytherapy Society

Purpose: To provide an update of the 2007 American brachytherapy survey on image-based brachytherapy, which showed that in the setting of treatment planning for gynecologic brachytherapy, although computed tomography (CT) was often used for treatment planning, most brachytherapists used point A for dose specification. Methods and Materials: A 45-question electronic survey on cervical cancer brachytherapy practice patterns was sent to all American Brachytherapy Society members and additional radiation oncologists and physicists based in the United States between January and September 2014. Responses from the 2007 survey and the present survey were compared using the χ{sup 2} test. Results: There were 370 respondents. Of those, only respondents, not in training, who treat more than 1 cervical cancer patient per year and practice in the United States, were included in the analysis (219). For dose specification to the target (cervix and tumor), 95% always use CT, and 34% always use MRI. However, 46% use point A only for dose specification to the target. There was a lot of variation in parameters used for dose evaluation of target volume and normal tissues. Compared with the 2007 survey, use of MRI has increased from 2% to 34% (P<.0001) for dose specification to the target. Use of volume-based dose delineation to the target has increased from 14% to 52% (P<.0001). Conclusion: Although use of image-based brachytherapy has increased in the United States since the 2007 survey, there is room for further growth, particularly with the use of MRI. This increase may be in part due to educational initiatives. However, there is still significant heterogeneity in brachytherapy practice in the United States, and future efforts should be geared toward standardizing treatment.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

The American Society for Radiation Oncology's 2015 Core Physics Curriculum for Radiation Oncology Residents

Purpose: The American Society for Radiation Oncology (ASTRO) Physics Core Curriculum Subcommittee (PCCSC) has updated the recommended physics curriculum for radiation oncology resident education to improve consistency in teaching, intensity, and subject matter. Methods and Materials: The ASTRO PCCSC is composed of physicists and physicians involved in radiation oncology residency education. The PCCSC updated existing sections within the curriculum, created new sections, and attempted to provide additional clinical context to the curricular material through creation of practical clinical experiences. Finally, we reviewed the American Board of Radiology (ABR) blueprint of examination topics for correlation with this curriculum. Results: The new curriculum represents 56 hours of resident physics didactic education, including a 4-hour initial orientation. The committee recommends completion of this curriculum at least twice to assure both timely presentation of material and re-emphasis after clinical experience. In addition, practical clinical physics and treatment planning modules were created as a supplement to the didactic training. Major changes to the curriculum include addition of Fundamental Physics, Stereotactic Radiosurgery/Stereotactic Body Radiation Therapy, and Safety and Incidents sections, and elimination of the Radiopharmaceutical Physics and Dosimetry and Hyperthermia sections. Simulation and Treatment Verification and optional Research and Development in Radiation Oncology sections were also added. A feedback loop was established with the ABR to help assure that the physics component of the ABR radiation oncology initial certification examination remains consistent with this curriculum. Conclusions: The ASTRO physics core curriculum for radiation oncology residents has been updated in an effort to identify the most important physics topics for preparing residents for careers in radiation oncology, to reflect changes in technology and practice since the publication of previous recommended curricula, and to provide practical training modules in clinical radiation oncology physics and treatment planning. The PCCSC is committed to keeping the curriculum current and consistent with the ABR examination blueprint.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

A Roadmap and Cost Implications of Establishing Comprehensive Cancer Care Using a Teleradiotherapy Network in a Group of Sub-Saharan African Countries With No Access to Radiation Therapy

Purpose: To propose a roadmap and explore the cost implications of establishing a teleradiotherapy network to provide comprehensive cancer care and capacity building in countries without access to radiation therapy. Methods and Materials: Ten low-income sub-Saharan countries with no current radiation therapy facilities were evaluated. A basic/secondary radiation therapy center (SRTC) with 2 teletherapy, 1 brachytherapy, 1 simulator, and a treatment planning facility was envisaged at a cost of 5 million US dollars (USD 5M). This could be networked with 1 to 4 primary radiation therapy centers (PRTC) with 1 teletherapy unit, each costing USD 2M. The numbers of PRTCs and SRTCs for each country were computed on the basis of cancer incidence, assuming that a PRTC and SRTC could respectively treat 450 and 900 patients annually. Results: An estimated 71,215 patients in these countries will need radiation therapy in 2020. Stepwise establishment of a network with 99 PRTCs and 28 SRTCs would result in 155 teletherapy units and 96% access to radiation therapy. A total of 310 radiation oncologists, 155 medical physicists, and 465 radiation therapy technologists would be needed. Capacity building could be undertaken through telementoring by networking to various international institutions and professional societies. Total infrastructure costs would be approximately USD 860.88M, only 0.94% of the average annual gross domestic product of these 10 countries. A total of 1.04 million patients could receive radiation therapy during the 15-year lifespan of a teletherapy unit for an investment of USD 826.69 per patient. For the entire population of 218.32 million, this equates to USD 4.11 per inhabitant. Conclusion: A teleradiotherapy network could be a cost-contained innovative health care strategy to provide effective comprehensive cancer care through resource sharing and capacity building. The network could also be expanded to include other allied specialties. The proposal calls for active coordination between all national and international organizations backed up by strong geopolitical commitment and action from all stakeholders.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Radiation Oncology and Online Patient Education Materials: Deviating From NIH and AMA Recommendations

Purpose: Physicians encourage patients to be informed about their health care options, but much of the online health care–related resources can be beneficial only if patients are capable of comprehending it. This study's aim was to assess the readability level of online patient education resources for radiation oncology to conclude whether they meet the general public's health literacy needs as determined by the guidelines of the United States National Institutes of Health (NIH) and the American Medical Association (AMA). Methods: Radiation oncology–related internet-based patient education materials were downloaded from 5 major professional websites (American Society for Radiation Oncology, American Association of Physicists in Medicine, American Brachytherapy Society, (RadiologyInfo.org), and Radiation Therapy Oncology Group). Additional patient education documents were downloaded by searching for key radiation oncology phrases using Google. A total of 135 articles were downloaded and assessed for their readability level using 10 quantitative readability scales that are widely accepted in the medical literature. Results: When all 10 assessment tools for readability were taken into account, the 135 online patient education articles were written at an average grade level of 13.7 ± 2.0. One hundred nine of the 135 articles (80.7%) required a high school graduate's comprehension level (12th-grade level or higher). Only 1 of the 135 articles (0.74%) met the AMA and NIH recommendations for patient education resources to be written between the third-grade and seventh-grade levels. Conclusion: Radiation oncology websites have patient education material written at an educational level above the NIH and AMA recommendations; as a result, average American patients may not be able to fully understand them. Rewriting radiation oncology patient education resources would likely contribute to the patients' understanding of their health and treatment options, making each physician-patient interaction more productive and efficient.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Development of a Quality and Safety Competency Curriculum for Radiation Oncology Residency: An International Delphi Study

Purpose: To develop an entry-to-practice quality and safety competency profile for radiation oncology residency. Methods and Materials: A comprehensive list of potential quality and safety competency items was generated from public and professional resources and interprofessional focus groups. Redundant or out-of-scope items were eliminated through investigator consensus. Remaining items were subjected to an international 2-round modified Delphi process involving experts in radiation oncology, radiation therapy, and medical physics. During Round 1, each item was scored independently on a 9-point Likert scale indicating appropriateness for inclusion in the competency profile. Items indistinctly ranked for inclusion or exclusion were re-evaluated through web conference discussion and reranked in Round 2. Results: An initial 1211 items were compiled from 32 international sources and distilled to 105 unique potential quality and safety competency items. Fifteen of the 50 invited experts participated in round 1: 10 radiation oncologists, 4 radiation therapists, and 1 medical physicist from 13 centers in 5 countries. Round 1 rankings resulted in 80 items included, 1 item excluded, and 24 items indeterminate. Two areas emerged more prominently within the latter group: change management and human factors. Web conference with 5 participants resulted in 9 of these 24 items edited for content or clarity. In Round 2, 12 participants rescored all indeterminate items resulting in 10 items ranked for inclusion. The final 90 enabling competency items were organized into thematic groups consisting of 18 key competencies under headings adapted from Deming's System of Profound Knowledge. Conclusions: This quality and safety competency profile may inform minimum training standards for radiation oncology residency programs.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2017

Quantitative Approach to Failure Mode and Effect Analysis for Linear Accelerator Quality Assurance

Purpose: To determine clinic-specific linear accelerator quality assurance (QA) TG-142 test frequencies, to maximize physicist time efficiency and patient treatment quality. Methods and Materials: A novel quantitative approach to failure mode and effect analysis is proposed. Nine linear accelerator-years of QA records provided data on failure occurrence rates. The severity of test failure was modeled by introducing corresponding errors into head and neck intensity modulated radiation therapy treatment plans. The relative risk of daily linear accelerator QA was calculated as a function of frequency of test performance. Results: Although the failure severity was greatest for daily imaging QA (imaging vs treatment isocenter and imaging positioning/repositioning), the failure occurrence rate was greatest for output and laser testing. The composite ranking results suggest that performing output and lasers tests daily, imaging versus treatment isocenter and imaging positioning/repositioning tests weekly, and optical distance indicator and jaws versus light field tests biweekly would be acceptable for non-stereotactic radiosurgery/stereotactic body radiation therapy linear accelerators. Conclusions: Failure mode and effect analysis is a useful tool to determine the relative importance of QA tests from TG-142. Because there are practical time limitations on how many QA tests can be performed, this analysis highlights which tests are the most important and suggests the frequency of testing based on each test's risk priority number.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System

Purpose: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. Methods and Materials: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data. Preliminary tests (“AP” and “3D-Bands”) were delivered to 9.5-cm usable diameter cylindrical PRESAGE dosimeters to validate the treatment planning system (TPS) for nonmodulated deliveries; assess the sensitivity, uniformity, and rotational symmetry of the PRESAGE dosimeters; and test the robustness of the remote dosimetry protocol. Following this, 4 clinical MRgIMRT plans (“MultiTarget,” “Prostate,” “Head/Neck,” and “C-Shape”) were measured using 13-cm usable diameter PRESAGE dosimeters. For all plans, 3D-γ (3% or 3 mm global, 10% threshold) passing rates were calculated and 3D-γ maps were examined. Point doses were measured with an IBA-CC01 ionization chamber for validation of absolute dose. Finally, by use of an in-house-developed, GPU-accelerated Monte Carlo algorithm (gPENELOPE), we independently calculated dose for all 6 Task Group 119 plans and compared against the TPS. Results: For PRESAGE measurements, 3D-γ analysis yielded passing rates of 98.7%, 99.2%, 98.5%, 98.0%, 99.2%, and 90.7% for AP, 3D-Bands, MultiTarget, Prostate, Head/Neck, and C-Shape, respectively. Ion chamber measurements were within an average of 0.5% (±1.1%) from the TPS dose. Monte Carlo calculations demonstrated good agreement with the TPS, with a mean 3D-γ passing rate of 98.5% ± 1.9% using a stricter 2%/2-mm criterion. Conclusions: We have validated the dosimetric accuracy of a commercial MRgIMRT system using high-resolution 3D techniques. We have demonstrated for the first time that hybrid 3D remote dosimetry is a comprehensive and feasible approach to commissioning MRgIMRT. This may provide better sensitivity in error detection compared with standard 2-dimensional measurements and could be used when implementing complex new magnetic resonance guided radiation therapy technologies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Low-dose-rate Brachytherapy for Prostate Cancer in Low-resource Settings

Purpose: In areas with limited health care, it is important to identify and implement effective treatment methods and to optimize available resources. We investigated the implementation of a low-dose-rate (LDR) brachytherapy program for the treatment of prostate cancer (PCa) in a low-resource setting such as Puerto Rico (PR), where PCa is the main cause of cancer-associated death. Methods and Materials: After institutional approval, the medical records of patients with nonmetastatic PCa undergoing LDR brachytherapy from 2008 to 2013 were reviewed from PR. The factors analyzed included adequate D{sub 90} (radiation dose delivered to 90% of the target volume) coverage (≥140 Gy), early and late toxicity (Common Terminology Criteria for Adverse Events grade >2), and prostate-specific antigen failure. Freedom from biochemical failure was evaluated using Kaplan-Meier analysis. Results: The barriers to implementation of LDR brachytherapy in a country with limited resources were identified. These included lack of access to funding for startup costs, specific referral patterns, lack of trained support staff, such as dosimetrists and physicists, and initial opposition from insurance companies for reimbursement. The initial results from 191 patients were included in the present study with a median follow-up period of 26 months. Prostate-specific antigen failure occurred in 6 patients (3%). No early or late gastrointestinal toxicity (grade >2) developed. Only 3 (2%) and 2 (1%) patients experienced early and late genitourinary toxicity (grade >2), respectively. The 2- and 3-year freedom from biochemical failure in this population was 97% and 95.9%, respectively. Conclusions: At present, limited data are available delineating the barriers faced by low-resource settings in the implementation of LDR brachytherapy. Our data highlight the issues unique to this environment and support the use of LDR brachytherapy as a reliable and effective treatment modality for patients with PCa in low-resource settings.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Single- and Multifraction Stereotactic Radiosurgery Dose/Volume Tolerances of the Brain

As part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy investigating normal tissue complication probability (NTCP) after hypofractionated radiation therapy, data from published reports (PubMed indexed 1995-2018) were pooled to identify dosimetric and clinical predictors of radiation-induced brain toxicity after single-fraction stereotactic radiosurgery (SRS) or fractionated stereotactic radiosurgery (fSRS).

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Prostate Stereotactic Body Radiation Therapy: An Overview of Toxicity and Dose Response

Ultrahypofractionationed radiation therapy for prostate cancer is increasingly studied and adopted. The American Association of Physicists in Medicine Working Group on Biological Effects of Hypofractionated Radiotherapy therefore aimed to review studies examining toxicity and quality of life after stereotactic body radiation therapy (SBRT) for prostate cancer and model its effect.

62 RADIOLOGY AND NUCLEAR MEDICINE↗