Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “physicists”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

MO-G-BRE-09: Validating FMEA Against Incident Learning Data: A Study in Stereotactic Body Radiation Therapy

Purpose: Though FMEA (Failure Mode and Effects Analysis) is becoming more widely adopted for risk assessment in radiation therapy, to our knowledge it has never been validated against actual incident learning data. The objective of this study was to perform an FMEA analysis of an SBRT (Stereotactic Body Radiation Therapy) treatment planning process and validate this against data recorded within an incident learning system. Methods: FMEA on the SBRT treatment planning process was carried out by a multidisciplinary group including radiation oncologists, medical physicists, and dosimetrists. Potential failure modes were identified through a systematic review of the workflow process. Failure modes were rated for severity, occurrence, and detectability on a scale of 1 to 10 and RPN (Risk Priority Number) was computed. Failure modes were then compared with historical reports identified as relevant to SBRT planning within a departmental incident learning system that had been active for two years. Differences were identified. Results: FMEA identified 63 failure modes. RPN values for the top 25% of failure modes ranged from 60 to 336. Analysis of the incident learning database identified 33 reported near-miss events related to SBRT planning. FMEA failed to anticipate 13 of these events, among which 3 were registered with severity ratings of severe or critical in the incident learning system. Combining both methods yielded a total of 76 failure modes, and when scored for RPN the 13 events missed by FMEA ranked within the middle half of all failure modes. Conclusion: FMEA, though valuable, is subject to certain limitations, among them the limited ability to anticipate all potential errors for a given process. This FMEA exercise failed to identify a significant number of possible errors (17%). Integration of FMEA with retrospective incident data may be able to render an improved overview of risks within a process.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

MO-G-12A-01: Quantitative Imaging Metrology: What Should Be Assessed and How?

The first two symposia in the Quantitative Imaging Track focused on 1) the introduction of quantitative imaging (QI) challenges and opportunities, and QI efforts of agencies and organizations such as the RSNA, NCI, FDA, and NIST, and 2) the techniques, applications, and challenges of QI, with specific examples from CT, PET/CT, and MR. This third symposium in the QI Track will focus on metrology and its importance in successfully advancing the QI field. While the specific focus will be on QI, many of the concepts presented are more broadly applicable to many areas of medical physics research and applications. As such, the topics discussed should be of interest to medical physicists involved in imaging as well as therapy. The first talk of the session will focus on the introduction to metrology and why it is critically important in QI. The second talk will focus on appropriate methods for technical performance assessment. The third talk will address statistically valid methods for algorithm comparison, a common problem not only in QI but also in other areas of medical physics. The final talk in the session will address strategies for publication of results that will allow statistically valid meta-analyses, which is critical for combining results of individual studies with typically small sample sizes in a manner that can best inform decisions and advance the field. Learning Objectives: Understand the importance of metrology in the QI efforts. Understand appropriate methods for technical performance assessment. Understand methods for comparing algorithms with or without reference data (i.e., “ground truth”). Understand the challenges and importance of reporting results in a manner that allows for statistically valid meta-analyses.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

TU-A-19A-01: Image Registration I: Deformable Image Registration, Contour Propagation and Dose Mapping: 101 and 201

Deformable image registration, contour propagation and dose mapping have become common, possibly essential tools for modern image-guided radiation therapy. Historically, these tools have been largely developed at academic medical centers and used in a rather limited and well controlled fashion. Today these tools are now available to the radiotherapy community at large, both as stand-alone applications and as integrated components of both treatment planning and treatment delivery systems. Unfortunately, the details of how these tools work and their limitations are not generally documented or described by the vendors that provide them. Although “it looks right”, determining that unphysical deformations may have occurred is crucial. Because of this, understanding how and when to use, and not use these tools to support everyday clinical decisions is far from straight forward. The goal of this session will be to present both the theory (basic and advanced) and practical clinical use of deformable image registration, contour propagation and dose mapping. To the extent possible, the “secret sauce” that different vendor use to produce reasonable/acceptable results will be described. A detailed explanation of the possible sources of errors and actual examples of these will be presented. Knowing the underlying principles of the process and understanding the confounding factors will help the practicing medical physicist be better able to make decisions (about making decisions) using these tools available. Learning Objectives: Understand the basic (101) and advanced (201) principles of deformable image registration, contour propagation and dose mapping data mapping. Understand the sources and impact of errors in registration and data mapping and the methods for evaluating the performance of these tools. Understand the clinical use and value of these tools, especially when used as a “black box”.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

TU-A-17A-01: Memorial to Benjamin M. Galkin - Memorial Lecture

This past year Medical Physics lost one of its active members, Benjamin M. Galkin. Ben Galkin was a Past-Treasurer of the AAPM. During his leadership role he played an important part in Securing membership, for the AAPM, in the American Institute of physics. As Treasurer he was also a prime mover in starting the journal, Medical Physics, and served as its business manager in the formative years.Ben Galkin received his Masters Degree at Columbia University in New York, under the mentorship of Dr. Edith Quimby, one of the pioneer Hospital Radiation Physicists in the country. He started his professional career at Jefferson Hospital in Philadelphia, joining Robert Gorson, and remained there until retirement. He served as the institution’s Radiation Safety Officer throughout his career. His research interest was Breast Imaging. He held joint faculty appointments in the Department of Radiology and the Department of Radiation Therapy and Nuclear Medicine, rising up to the rank of Full professor. He was a well respected teacher for the residents in Radiology.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

TU-B-16A-01: To Which Journal Should I Submit My Paper

Research papers authored by Medical Physicists address a large spectrum of oncologic, imaging, or basic research problems; exploit a wide range of physical and engineering methodologies; and often describe the efforts of a multidisciplinary research team. Given the large number (about 100) competing journals accepting medical physics articles, it may not be clear to an individual author which journal is the best venue for disseminating their work to the scientific community. Relevant factors usually include the Journal’s audience and scientific impact, but also such factors as perceived acceptance rate, interest in their topic, and quality of service. The purpose of this symposium is to provide the medical physics community with an overview of scope, review processes, and article guidelines for the following journals: Medical Physics, International Journal of Radiation Biology and Physics, Journal of Applied Clinical Medical Physics, and Practical Radiation Oncology. The senior editors for each journal will provide details as to the journals review process, for example: single blind versus double blind reviews; the hierarchy of the review process in terms of editorial board structure; the reality of acceptance, in terms of acceptance rate; and the types of research the journal prefers to publish. The goal is to provide for authors guidance before they begin to write their papers, not only for proper formatting, but also that the readership is appropriate for the particular paper, hopefully increasing the likelihood of publication. Learning Objectives: To review each Journal’s submission and review process Guidance as to how to increase chances of acceptance To help decipher which journal is appropriate for a given work.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2014

TU-C-BRE-03: Aggregation of Linac Measurement Data

Purpose: Accurate data of linear accelerator radiation characteristics is important for treatment planning system commissioning as well as regular quality assurance of the machine. The RPC has performed site visits of numerous machines . Data gathered from Varian machines from the past 15 years are presented. The data collected can be used as a secondary check or when commissioning a new machine to verify that values are reasonable. Methods: Data from the past 15 years of RPC site visits was compiled and analyzed. Data was composed from measurements from approximately 400 Varian machines. Each dataset consists of several point measurements at various locations in a water phantom to measure percentage depth dose, output factors, including small MLC fields, off-axis factors, and wedge factors if applicable. Common statistical values are presented for each machine type. Where applicable, data was compared to other reference data given by the vendor or a select number of previous researchers. Results: Data is separated by energy and parameter and then analyzed by machine class. Data distributions of the parameter data were normal except occasionally at the tails. Distributions of the data for each class and parameter are tabulated to give not simply a singular reference value, but metrics about the distribution: 5th and 95th percentile values and the standard deviation as well as the median. Conclusion: The RPC has collected numerous data on Varian linacs and presented the finding of the past 15 years. The data can be used as a reference data set for physicists to compare against. A linac that deviates from the values does not necessarily indicate there is a problem as long as the treatment planning system correlates to the machine. Comparison of linac and treatment planning system data to external reference data can prevent serious treatment errors.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

TU-C-18A-01: Models of Risk From Low-Dose Radiation Exposures: What Does the Evidence Say?

At dose levels of (approximately) 500 mSv or more, increased cancer incidence and mortality have been clearly demonstrated. However, at the low doses of radiation used in medical imaging, the relationship between dose and cancer risk is not well established. As such, assumptions about the shape of the dose-response curve are made. These assumptions, or risk models, are used to estimate potential long term effects. Common models include 1) the linear non-threshold (LNT) model, 2) threshold models with either a linear or curvilinear dose response above the threshold, and 3) a hormetic model, where the risk is initially decreased below background levels before increasing. The choice of model used when making radiation risk or protection calculations and decisions can have significant implications on public policy and health care decisions. However, the ongoing debate about which risk model best describes the dose-response relationship at low doses of radiation makes informed decision making difficult. This symposium will review the two fundamental approaches to determining the risk associated with low doses of ionizing radiation, namely radiation epidemiology and radiation biology. The strengths and limitations of each approach will be reviewed, the results of recent studies presented, and the appropriateness of different risk models for various real world scenarios discussed. Examples of well-designed and poorly-designed studies will be provided to assist medical physicists in 1) critically evaluating publications in the field and 2) communicating accurate information to medical professionals, patients, and members of the general public. Equipped with the best information that radiation epidemiology and radiation biology can currently provide, and an understanding of the limitations of such information, individuals and organizations will be able to make more informed decisions regarding questions such as 1) how much shielding to install at medical facilities, 2) at what dose level are risk vs. benefit discussions with patients appropriate, 3) at what dose level should we tell a pregnant woman that the baby’s health risk from a prenatal radiation exposure is “significant”, 4) is informed consent needed for patients undergoing medical imaging, and 5) at what dose level is evacuation appropriate after a radiological accident. Examples of the tremendous impact that choosing different risks models can have on the answers to these types of questions will be given.A moderated panel discussion will allow audience members to pose questions to the faculty members, each of whom is an established expert in his respective discipline. Learning Objectives: Understand the fundamental principles, strengths and limitations of radiation epidemiology and radiation biology for determining the risk from exposures to low doses of ionizing radiation Become familiar with common models of risk used to describe the dose-response relationship at low dose levels Learn to identify strengths and weaknesses in studies designed to measure the effect of low doses of ionizing radiation Understand the implications of different risk models on public policy and health care decisions.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

TU-PIS-Exhibit Hall-01: CT Dose Optimization Technologies II

Partners in Solutions is an exciting new program in which AAPM partners with our vendors to present practical “hands-on” information about the equipment and software systems that we use in our clinics. The imaging topic this year is CT scanner dose optimization capabilities. Note that the sessions are being held in a special purpose room built on the Exhibit Hall Floor, to encourage further interaction with the vendors. Siemens‘ Commitment to the Right Dose in Computed Tomography Presentation Time: 11:15 - 11:45 AM Providing sustainable clinical results at highest patient safety: This is the challenge in medical imaging. Especially for Computed Tomography this means applying not simply the lowest, but the right dose for sound diagnostic imaging. Consequently, Siemens is committed to deliver the right dose in CT. In order to reduce radiation to the right dose, the first step is to provide the right dose technology. Through decades of research and development in CT imaging, Siemens CT has constantly introduced new ideas leading to a comprehensive portfolio of unique CARE technologies to deliver the right dose. For example automated kV adjustment based on patient size and the clinical question with CARE kV and three generations of iterative reconstruction. Based on the right dose technology, the next step is to actually scan at the right dose. For this, it is key to know the right dose targets for every examination. Siemens continuously involves CT experts to push developments further and outline how users can best adapt their procedures to the right dose. For users to know whether they met the right dose targets, it is therefore important to understand and monitor the actual absolute dose values. All scanners are delivered with defined default protocols which automatically use the available right dose technologies. Finally, to deliver the right dose not just in singular cases, but ideally to patients everywhere, organizations need then to manage dose across their institutions. Here Siemens offers the right dose management tools for administrations to analyze and document dose, to train their clinical staff and to continuously optimize the application of the right dose in clinical routine. Siemens CT is not only adhering to the ALARA principle, but is inspired by it. With CARE Right Siemens show their commitment to the right dose in CT. Toshiba Aquilion CT Dose Management Tools Presentation Time: 11:45 - 12:15 PM A practical review of Toshiba’s CT dose management technologies from the physicist’s perspective. This presentation will include an overview of Toshiba’s CT dose reduction technologies and dose safeguards. Content will include answers to frequently asked questions relating to dose management, dose tracking, CTDI measurement, ACR accreditation, ACR QC, and protocol review on Toshiba CT systems. Specific topics will include the following: Toshiba’s mechanism of tube current modulation; Exposure record format and interpretation of the values; Dose reporting and dose safeguard tools; Use of AIDR 3D iterative reconstruction; The configuration of task specific image quality target and its integration with AIDR 3D; Tips for scanning the ACR phantom with wide beam geometry; Measuring CTDI for wide beam geometry; Discussion of daily QC procedures and specifications; Tips for annual QC evaluation; Protocol management tools.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

TU-F-16A-01: Communicating Risk

The radiobiological risks associated with medical imaging are generally considered to be small, if existent. However, the public view of the risk of medical radiation at diagnostic levels can be substantially different from the clinical reality. Radiation science is not taught to the general public, and so perception of radiation risks can be based on a variety sources, including some that may be misleading, incorrect, or sensationalized. Consequently, patients can have significant concerns about procedures they or their loved ones might have had or that might be needed in their medical care. It is the responsibility of the physicist to be able to communicate risk in a manner that is clear, understandable, and respectful. This session will present a number of real life scenarios of patient or family concern about radiation risks. The panel will, through demonstration or discussion, present various options for handling each situation. The audience will be involved in discussion and critique of the approaches presented. Learning Objectives: To gain insight to the patients perspective on radiation risk and how to respond professionally to their concerns. To learn basic principles for effectively communicating with patients about radiation risk. To gain tools and approaches for addressing a wide range of patient concerns.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

WE-A-BRD-01: Innovation in Radiation Therapy Planning I: Knowledge Guided Treatment Planning

Intensity modulated radiation therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) offer the capability of normal tissues and organs sparing. However, the exact amount of sparing is often unknown until the plan is complete. This lack of prior guidance has led to the iterative, trial and-error approach in current planning practice. Even with this effort the search for patient-specific optimal organ sparing is still strongly influenced by planner's experience. While experience generally helps in maximizing the dosimetric advantages of IMRT/VMAT, there have been several reports showing unnecessarily high degree of plan quality variability at individual institutions and amongst different institutions, even with a large amount of experience and the best available tools. Further, when physician and physicist evaluate a plan, the dosimetric quality of the plan is often compared with a standard protocol that ignores individual patient anatomy and tumor characteristic variations. In recent years, developments of knowledge models for clinical IMRT/VMAT planning guidance have shown promising clinical potentials. These knowledge models extract past expert clinical experience into mathematical models that predict dose sparing references at patient-specific level. For physicians and planners, these references provide objective values that reflect best achievable dosimetric constraints. For quality assurance, applying patient-specific dosimetry requirements will enable more quantitative and objective assessment of protocol compliance for complex IMRT planning. Learning Objectives: Modeling and representation of knowledge for knowledge-guided treatment planning. Demonstrations of knowledge-guided treatment planning with a few clinical caanatomical sites. Validation and evaluation of knowledge models for cost and quality effective standardization of plan optimization.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

WE-B-19A-01: SRT II: Uncertainties in SRT

SRS delivery has undergone major technical changes in the last decade, transitioning from predominantly frame-based treatment delivery to imageguided, frameless SRS. It is important for medical physicists working in SRS to understand the magnitude and sources of uncertainty involved in delivering SRS treatments for a multitude of technologies (Gamma Knife, CyberKnife, linac-based SRS and protons). Sources of SRS planning and delivery uncertainty include dose calculation, dose fusion, and intra- and inter-fraction motion. Dose calculations for small fields are particularly difficult because of the lack of electronic equilibrium and greater effect of inhomogeneities within and near the PTV. Going frameless introduces greater setup uncertainties that allows for potentially increased intra- and interfraction motion, The increased use of multiple imaging modalities to determine the tumor volume, necessitates (deformable) image and contour fusion, and the resulting uncertainties introduced in the image registration process further contribute to overall treatment planning uncertainties. Each of these uncertainties must be quantified and their impact on treatment delivery accuracy understood. If necessary, the uncertainties may then be accounted for during treatment planning either through techniques to make the uncertainty explicit, or by the appropriate addition of PTV margins. Further complicating matters, the statistics of 1-5 fraction SRS treatments differ from traditional margin recipes relying on Poisson statistics. In this session, we will discuss uncertainties introduced during each step of the SRS treatment planning and delivery process and present margin recipes to appropriately account for such uncertainties. Learning Objectives: To understand the major contributors to the total delivery uncertainty in SRS for Gamma Knife, CyberKnife, and linac-based SRS. Learn the various uncertainties introduced by image fusion, deformable image registration, and contouring variation. Learn a variety of strategies for dealing with uncertainty, including margin recipes and explicit visualization of uncertainty. Understand how the assessment of PTV margins differs from regular fractionation (van Herk recipe) for 1–5 fraction deliveries.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

WE-D-9A-06: Open Source Monitor Calibration and Quality Control Software for Enterprise Display Management

Purpose: Medical display monitor calibration and quality control present challenges to medical physicists. The purpose of this work is to demonstrate and share experiences with an open source package that allows for both initial monitor setup and routine performance evaluation. Methods: A software package, pacsDisplay, has been developed over the last decade to aid in the calibration of all monitors within the radiology group in our health system. The software is used to calibrate monitors to follow the DICOM Grayscale Standard Display Function (GSDF) via lookup tables installed on the workstation. Additional functionality facilitates periodic evaluations of both primary and secondary medical monitors to ensure satisfactory performance. This software is installed on all radiology workstations, and can also be run as a stand-alone tool from a USB disk. Recently, a database has been developed to store and centralize the monitor performance data and to provide long-term trends for compliance with internal standards and various accrediting organizations. Results: Implementation and utilization of pacsDisplay has resulted in improved monitor performance across the health system. Monitor testing is now performed at regular intervals and the software is being used across multiple imaging modalities. Monitor performance characteristics such as maximum and minimum luminance, ambient luminance and illuminance, color tracking, and GSDF conformity are loaded into a centralized database for system performance comparisons. Compliance reports for organizations such as MQSA, ACR, and TJC are generated automatically and stored in the same database. Conclusion: An open source software solution has simplified and improved the standardization of displays within our health system. This work serves as an example method for calibrating and testing monitors within an enterprise health system.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

WE-G-17A-06: A Water Calorimeter for Use in MRI Linacs

Purpose: At VSL, Dutch Metrology Institute, a new water calorimeter was developed with the purpose to replace the existing primary standard for absorbed dose to water in the Netherlands. The new water calorimeter is designed to be operable in medium- to high energy photon beams, electrons, protons as well as MRI integrated linear accelerators. VSL has operated a water calorimeter since 2001. This calorimeter formed the basis for the NCS-18 dosimetry protocol, which is commonly applied by medical physicists in the Netherlands and Belgium. Methods: The unit Gray is the unit of interest for measurement of the absorbed dose to water. Water calorimetry involves the measurement of a small temperature rise (0.24 mK/Gy) with an uncertainty of less than 1 μK/Gy at a temperature of 4 °C. Using extensive multi-physics simulations the new calorimeter's thermal performance was simulated before it was constructed at the end of 2013. With the advent of radiotherapy treatment units incorporating MR imaging the performance of the thermistor temperature sensors were characterized in a 1.5 T magnetic field. Results: A change of thermistor resistance was observed of less than 0.004% as a Result of the magneto-resistance effect in a 1.5 T magnetic field. Although a magneto-resistance effect was detectable, the effect on the temperature response in the water calorimeter was found to be negligible. Conclusion: With the realization of the new calorimeter operable in MRI linacs and designed for use in a variety of beam modalities, VSL is ready for accurate dosimetry in new advanced radiotherapy modalities. Due to the small form factor the calorimeter can be used on location in the actual therapy beam inside a 68 cm linac bore. This work was supported by EMRP grant HLT06. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

TH-A-18A-01: Innovation in Clinical Breast Imaging

Several novel modalities have been or are on the verge of being introduced into the breast imaging clinic. These include tomosynthesis imaging, dedicated breast CT, contrast-enhanced digital mammography, and automated breast ultrasound, all of which are covered in this course. Tomosynthesis and dedicated breast CT address the problem of tissue superimposition that limits mammography screening performance, by improved or full resolution of the 3D breast morphology. Contrast-enhanced digital mammography provides functional information that allows for visualization of tumor angiogenesis. 3D breast ultrasound has high sensitivity for tumor detection in dense breasts, but the imaging exam was traditionally performed by radiologists. In automated breast ultrasound, the scan is performed in an automated fashion, making for a more practical imaging tool, that is now used as an adjunct to digital mammography in breast cancer screening. This course will provide medical physicists with an in-depth understanding of the imaging physics of each of these four novel imaging techniques, as well as the rationale and implementation of QC procedures. Further, basic clinical applications and work flow issues will be discussed. Learning Objectives: To be able to describe the underlying physical and physiological principles of each imaging technique, and to understand the corresponding imaging acquisition process. To be able to describe the critical system components and their performance requirements. To understand the rationale and implementation of quality control procedures, as well as regulatory requirements for systems with FDA approval. To learn about clinical applications and understand risks and benefits/strength and weakness of each modality in terms of clinical breast imaging.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

TH-C-19A-08: PDD Discrepancies at Opposite Biases From Very Small Volume Ion Chambers When Using Water Scanners

Purpose: As more so-called micro ion chambers become commercially available, medical physicists may be inclined to use them during the linear accelerator commissioning process, in an attempt to better characterize the beam in steep dose gradient areas. The purpose of this work is to inform the medical physics community of a non-trivial, anomalous behavior observed when very small chambers are used in certain beam scanning configurations. Methods: A total of six ion chambers (0.007cc to 0.6cc) were used to scan PDDs from a 10×10cm2 field at both +300V and −300V biases. PDDs were scanned using three different water tank scanning systems to determine whether different scanners exhibit the same abnormality. Finally, PDDs were sampled using an external electrometer to bypass the internal electrometer of the scanner to determine the potential contributions of the scanner electronics to the abnormality observed. Results: We observed a reproducible, significant difference (over-response with depth) in PDDs acquired when using very small ion chambers with certain bias and watertank combinations, on the order of 3–5% at a depth of 25 cm in water. This difference was not observed when the PDDs were sampled using the ion chambers in conjunction with an external electrometer. This suggests a contribution of interference produced by the controller box and scanning system, which becomes significant for the very small signals collected by very small ion chambers, especially at depth, as the signal level is reduced even further. Conclusion: Based on the results observed here, if currently available very small ion chambers are used with specific bias and scanning water-tank combinations, erroneous PDD data may be collected. If this data is used as input to the Treatment Planning System, systematic errors on the order of 3%–5% may be introduced into the treatment planning process.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

TH-C-18A-08: A Management Tool for CT Dose Monitoring, Analysis, and Protocol Review

Purpose: To develop a customizable tool for enterprise-wide managing of CT protocols and analyzing radiation dose information of CT exams for a variety of quality control applications Methods: All clinical CT protocols implemented on the 11 CT scanners at our institution were extracted in digital format. The original protocols had been preset by our CT management team. A commercial CT dose tracking software (DoseWatch,GE healthcare,WI) was used to collect exam information (exam date, patient age etc.), scanning parameters, and radiation doses for all CT exams. We developed a Matlab-based program (MathWorks,MA) with graphic user interface which allows to analyze the scanning protocols with the actual dose estimates, and compare the data to national (ACR,AAPM) and internal reference values for CT quality control. Results: The CT protocol review portion of our tool allows the user to look up the scanning and image reconstruction parameters of any protocol on any of the installed CT systems among about 120 protocols per scanner. In the dose analysis tool, dose information of all CT exams (from 05/2013 to 02/2014) was stratified on a protocol level, and within a protocol down to series level, i.e. each individual exposure event. This allows numerical and graphical review of dose information of any combination of scanner models, protocols and series. The key functions of the tool include: statistics of CTDI, DLP and SSDE, dose monitoring using user-set CTDI/DLP/SSDE thresholds, look-up of any CT exam dose data, and CT protocol review. Conclusion: our inhouse CT management tool provides radiologists, technologists and administration a first-hand near real-time enterprise-wide knowledge on CT dose levels of different exam types. Medical physicists use this tool to manage CT protocols, compare and optimize dose levels across different scanner models. It provides technologists feedback on CT scanning operation, and knowledge on important dose baselines and thresholds.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

SU-C-BRD-05: Implementation of Incident Learning in the Safety and Quality Management of Radiotherapy: The Primary Experience in a New Established Program with Advanced Techniques

Purpose: To explore the implementation and effectiveness of incident learning for the safety and quality of radiotherapy in a new established radiotherapy program with advanced technology. Methods: Reference to the consensus recommendations by American Association of Physicist in Medicine, an incident learning system was specifically designed for reporting, investigating, and learning of individual radiotherapy incidents in a new established radiotherapy program, with 4D CBCT, Ultrasound guided radiotherapy, VMAT, gated treatment delivered on two new installed linacs. The incidents occurring in external beam radiotherapy from February, 2012 to January, 2014 were reported. Results: A total of 33 reports were analyzed, including 28 near misses and 5 incidents. Among them, 5 originated in imaging for planning, 25 in planning, 1 in plan transfer, 1 in commissioning and 1 in treatment delivery. Among them, three near misses originated in the safety barrier of the radiotherapy process. In terms of error type, 1 incident was classified as wrong patient, 7 near misses/incidents as wrong site, 6 as wrong laterality, 5 as wrong dose, 7 as wrong prescription, and 7 as suboptimal plan quality. 5 incidents were all classified as grade 1/2 of dosimetric severity, 1 as grade 0, and the other 4 as grade 1 of medical severity. For the causes/contributory factors, negligence, policy not followed, inadequate training, failure to develop an effective plan, and communication contributed to 19, 15, 12, 5 and 3 near misses/incidents, respectively. The average incident rate per 100 patients treated was 0.4; this rate fell to 0.28% in the second year from 0.56% in the first year. The rate of near miss fell to 1.24% from 2.22%. Conclusion: Effective incident learning can reduce the occurrence of near miss/incidents, enhance the culture of safety. Incident learning is an effective proactive method for improving the quality and safety of radiotherapy.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

Process-based quality management for clinical implementation of adaptive radiotherapy

Purpose: Intensity-modulated adaptive radiotherapy (ART) has been the focus of considerable research and developmental work due to its potential therapeutic benefits. However, in light of its unique quality assurance (QA) challenges, no one has described a robust framework for its clinical implementation. In fact, recent position papers by ASTRO and AAPM have firmly endorsed pretreatment patient-specific IMRT QA, which limits the feasibility of online ART. The authors aim to address these obstacles by applying failure mode and effects analysis (FMEA) to identify high-priority errors and appropriate risk-mitigation strategies for clinical implementation of intensity-modulated ART. Methods: An experienced team of two clinical medical physicists, one clinical engineer, and one radiation oncologist was assembled to perform a standard FMEA for intensity-modulated ART. A set of 216 potential radiotherapy failures composed by the forthcoming AAPM task group 100 (TG-100) was used as the basis. Of the 216 failures, 127 were identified as most relevant to an ART scheme. Using the associated TG-100 FMEA values as a baseline, the team considered how the likeliness of occurrence (O), outcome severity (S), and likeliness of failure being undetected (D) would change for ART. New risk priority numbers (RPN) were calculated. Failures characterized by RPN ≥ 200 were identified as potentially critical. Results: FMEA revealed that ART RPN increased for 38% (n = 48/127) of potential failures, with 75% (n = 36/48) attributed to failures in the segmentation and treatment planning processes. Forty-three of 127 failures were identified as potentially critical. Risk-mitigation strategies include implementing a suite of quality control and decision support software, specialty QA software/hardware tools, and an increase in specially trained personnel. Conclusions: Results of the FMEA-based risk assessment demonstrate that intensity-modulated ART introduces different (but not necessarily more) risks than standard IMRT and may be safely implemented with the proper mitigations.

60 APPLIED LIFE SCIENCES↗