Engineering topics

Pawlicki, T

Publications and source records attributed to Pawlicki, T.

11 records

DOE OSTI2016

SU-F-E-12: Elective International Rotations in Medical Physics Residency Programs

Purpose: The purpose of this educational program is to motivate talented, intelligent individuals to become stakeholders in the global effort to improve access to radiotherapy. Methods: The need to improve global access to radiotherapy has been clearly established and several organizations are making substantial progress in securing funding and developing plans to achieve this worthwhile goal. The incorporation of elective international rotations in residency programs may provide one possible mechanism to promote and support this future investment. We recently incorporated an elective 1-month international rotation into our CAMPEP accredited Medical Physics residency program, with our first rotation taking place in Vietnam. A unique aspect of this rotation was that it was scheduled collaboratively with our Radiation Oncology residency program such that Radiation Oncology and Medical Physics residents traveled to the same clinic at the same time. Results: We believe the international rotation substantially enhances the educational experience, providing additional benefits to residents by increasing cross-disciplinary learning and offering a shared learning experience. The combined international rotation may also increase benefit to the host institution by modeling positive multidisciplinary working relationships between Radiation Oncologists and Medical Physicists. Our first resident returned with several ideas designed to improve radiotherapy in resource-limited settings – one of which is currently being pursued in collaboration with a vendor. Conclusion: The elective international rotation provides a unique learning experience that has the potential to motivate residents to become stakeholders in the global effort to improve access to radiotherapy. What better way to prepare the next generation of Medical Physicists to meet the challenges of improving global access to radiotherapy than to provide them with training experiences that motivate them to be socially conscious and equip them with the clinical and problem solving skills required to deliver effective treatments in resource limited settings?.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-F-T-246: Evaluation of Healthcare Failure Mode And Effect Analysis For Risk Assessment

Purpose: To evaluate the differences between the Veteran Affairs Healthcare Failure Modes and Effect Analysis (HFMEA) and the AAPM Task Group 100 Failure and Effect Analysis (FMEA) risk assessment techniques in the setting of a stereotactic radiosurgery (SRS) procedure were compared respectively. Understanding the differences in the techniques methodologies and outcomes will provide further insight into the applicability and utility of risk assessments exercises in radiation therapy. Methods: HFMEA risk assessment analysis was performed on a stereotactic radiosurgery procedure. A previous study from our institution completed a FMEA of our SRS procedure and the process map generated from this work was used for the HFMEA. The process of performing the HFMEA scoring was analyzed, and the results from both analyses were compared. Results: The key differences between the two risk assessments are the scoring criteria for failure modes and identifying critical failure modes for potential hazards. The general consensus among the team performing the analyses was that scoring for the HFMEA was simpler and more intuitive then the FMEA. The FMEA identified 25 critical failure modes while the HFMEA identified 39. Seven of the FMEA critical failure modes were not identified by the HFMEA and 21 of the HFMEA critical failure modes were not identified by the FMEA. HFMEA as described by the Veteran Affairs provides guidelines on which failure modes to address first. Conclusion: HFMEA is a more efficient model for identifying gross risks in a process than FMEA. Clinics with minimal staff, time and resources can benefit from this type of risk assessment to eliminate or mitigate high risk hazards with nominal effort. FMEA can provide more in depth details but at the cost of elevated effort.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

SU-C-304-02: Robust and Efficient Process for Acceptance Testing of Varian TrueBeam Linacs Using An Electronic Portal Imaging Device (EPID)

Purpose: The purpose of this project was to develop a process that utilizes the onboard kV and MV electronic portal imaging devices (EPIDs) to perform rapid acceptance testing (AT) of linacs in order to improve efficiency and standardize AT equipment and processes. Methods: In this study a Varian TrueBeam linac equipped with an amorphous silicon based EPID (aSi1000) was used. The conventional set of AT tests and tolerances was used as a baseline guide, and a novel methodology was developed to perform as many tests as possible using EPID exclusively. The developer mode on Varian TrueBeam linac was used to automate the process. In the current AT process there are about 45 tests that call for customer demos. Many of the geometric tests such as jaw alignment and MLC positioning are performed with highly manual methods, such as using graph paper. The goal of the new methodology was to achieve quantitative testing while reducing variability in data acquisition, analysis and interpretation of the results. The developed process was validated on two machines at two different institutions. Results: At least 25 of the 45 (56%) tests which required customer demo can be streamlined and performed using EPIDs. More than half of the AT tests can be fully automated using the developer mode, while others still require some user interaction. Overall, the preliminary data shows that EPID-based linac AT can be performed in less than a day, compared to 2–3 days using conventional methods. Conclusions: Our preliminary results show that performance of onboard imagers is quite suitable for both geometric and dosimetric testing of TrueBeam systems. A standardized AT process can tremendously improve efficiency, and minimize the variability related to third party quality assurance (QA) equipment and the available onsite expertise. Research funding provided by Varian Medical Systems. Dr. Sasa Mutic receives compensation for providing patient safety training services from Varian Medical Systems, the sponsor of this study.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2015

SU-D-BRD-05: Online Framework for Plan Tracking and Automatic Checks in Radiation Therapy

Purpose: To develop an online framework that tracks a patient’s plan from initial simulation to treatment and that helps automate elements of the physics plan checks usually performed in the record and verify (RV) system and treatment planning system. Methods: We have developed PlanTracker, an online plan tracking system that automatically imports new patients tasks and follows it through treatment planning, physics checks, therapy check, and chart rounds. A survey was designed to collect information about the amount of time spent by medical physicists in non-physics related tasks. We then assessed these non-physics tasks for automation. Using these surveys, we directed our PlanTracker software development towards the automation of intra-plan physics review. We then conducted a systematic evaluation of PlanTracker’s accuracy by generating test plans in the RV system software designed to mimic real plans, in order to test its efficacy in catching errors both real and theoretical. Results: PlanTracker has proven to be an effective improvement to the clinical workflow in a radiotherapy clinic. We present data indicating that roughly 1/3 of the physics plan check can be automated, and the workflow optimized, and show the functionality of PlanTracker. When the full system is in clinical use we will present data on improvement of time use in comparison to survey data prior to PlanTracker implementation. Conclusion: We have developed a framework for plan tracking and automatic checks in radiation therapy. We anticipate using PlanTracker as a basis for further development in clinical/research software. We hope that by eliminating the most simple and time consuming checks, medical physicists may be able to spend their time on plan quality and other physics tasks rather than in arithmetic and logic checks. We see this development as part of a broader initiative to advance the clinical/research informatics infrastructure surrounding the radiotherapy clinic. This research project has been financially supported by Varian Medical Systems, Palo Alto, CA, through a Varian MRA.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

SU-E-T-87: A TG-100 Approach for Quality Improvement of Associated Dosimetry Equipment

Purpose: Dosimetry protocols devote so much time to the discussion of ionization chamber choice, use and performance that is easy to forget about the importance of the associated dosimetry equipment (ADE) in radiation dosimetry - barometer, thermometer, electrometer, phantoms, triaxial cables, etc. Improper use and inaccuracy of these devices may significantly affect the accuracy of radiation dosimetry. The purpose of this study is to evaluate the risk factors in the monthly output dosimetry procedure and recommend corrective actions using a TG-100 approach. Methods: A failure mode and effects analysis (FMEA) of the monthly linac output check procedure was performed to determine which steps and failure modes carried the greatest risk. In addition, a fault tree analysis (FTA) was performed to expand the initial list of failure modes making sure that none were overlooked. After determining the failure modes with the highest risk priority numbers (RPNs), 11 physicists were asked to score corrective actions based on their ease of implementation and potential impact. The results were aggregated into an impact map to determine the implementable corrective actions. Results: Three of the top five failure modes were related to the thermometer and barometer. The two highest RPN-ranked failure modes were related to barometric pressure inaccuracy due to their high lack-of-detectability scores. Six corrective actions were proposed to address barometric pressure inaccuracy, and the survey results found the following two corrective actions to be implementable: 1) send the barometer for recalibration at a calibration laboratory and 2) check the barometer accuracy against the local airport and correct for elevation. Conclusion: An FMEA on monthly output measurements displayed the importance of ADE for accurate radiation dosimetry. When brainstorming for corrective actions, an impact map is helpful for visualizing the overall impact versus the ease of implementation.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2015

SU-E-T-269: Differential Hazard Analysis For Conventional And New Linac Acceptance Testing Procedures

Purpose: New techniques and materials have recently been developed to expedite the conventional Linac Acceptance Testing Procedure (ATP). The new ATP method uses the Electronic Portal Imaging Device (EPID) for data collection and is presented separately. This new procedure is meant to be more efficient then conventional methods. While not clinically implemented yet, a prospective risk assessment is warranted for any new techniques. The purpose of this work is to investigate the risks and establish the pros and cons between the conventional approach and the new ATP method. Methods: ATP tests that were modified and performed with the EPID were analyzed. Five domain experts (Medical Physicists) comprised the core analysis team. Ranking scales were adopted from previous publications related to TG 100. The number of failure pathways for each ATP test procedure were compared as well as the number of risk priority numbers (RPN’s) greater than 100 were compared. Results: There were fewer failure pathways with the new ATP compared to the conventional, 262 and 556, respectively. There were fewer RPN’s > 100 in the new ATP compared to the conventional, 41 and 115. Failure pathways and RPN’s > 100 for individual ATP tests on average were 2 and 3.5 times higher in the conventional ATP compared to the new, respectively. The pixel sensitivity map of the EPID was identified as a key hazard to the new ATP procedure with an RPN of 288 for verifying beam parameters. Conclusion: The significant decrease in failure pathways and RPN’s >100 for the new ATP mitigates the possibilities of a catastrophic error occurring. The Pixel Sensitivity Map determining the response and inherent characteristics of the EPID is crucial as all data and hence results are dependent on that process. Grant from Varian Medical Systems Inc.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

WE-G-BRA-06: Application of Systems and Control Theory-Based Hazard Analysis to Radiotherapy

Purpose: The process of delivering radiation occurs in a complex socio-technical system heavily reliant on human operators. Furthermore, both humans and software are notoriously challenging to account for in traditional hazard analysis models. High reliability industries such as aviation have approached this problem through using hazard analysis techniques grounded in systems and control theory. The purpose of this work is to apply the Systems Theoretic Accident Model Processes (STAMP) hazard model to radiotherapy. In particular, the System-Theoretic Process Analysis (STPA) approach is used to perform a hazard analysis of a proposed on-line adaptive cranial radiosurgery procedure that omits the CT Simulation step and uses only CBCT for planning, localization, and treatment. Methods: The STPA procedure first requires the definition of high-level accidents and hazards leading to those accidents. From there, hierarchical control structures were created followed by the identification and description of control actions for each control structure. Utilizing these control structures, unsafe states of each control action were created. Scenarios contributing to unsafe control action states were then identified and translated into system requirements to constrain process behavior within safe boundaries. Results: Ten control structures were created for this new CBCT-only process which covered the areas of hospital and department management, treatment design and delivery, and vendor service. Twenty three control actions were identified that contributed to over 80 unsafe states of those control actions resulting in over 220 failure scenarios. Conclusion: The interaction of people, hardware, and software are highlighted through the STPA approach. STPA provides a hierarchical model for understanding the role of management decisions in impacting system safety so that a process design requirement can be traced back to the hazard and accident that it is intended to mitigate. Varian Medical Systems, Inc.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2014

MO-E-18C-01: Open Access Web-Based Peer-To-Peer Training and Education in Radiotherapy

Purpose: Current training and education delivery models have limitations which result in gaps in clinical proficiency with equipment, procedures, and techniques. Educational and training opportunities offered by vendors and professional societies are by their nature not available at point of need or for the life of clinical systems. The objective of this work is to leverage modern communications technology to provide peer-to-peer training and education for radiotherapy professionals, in the clinic and on demand, as they undertake their clinical duties. Methods: We have developed a free of charge web site ( https://i.treatsafely.org ) using the Google App Engine and datastore (NDB, GQL), Python with AJAX-RPC, and Javascript. The site is a radiotherapy-specific hosting service to which user-created videos illustrating clinical or physics processes and other relevant educational material can be uploaded. Efficient navigation to the material of interest is provided through several RT specific search tools and videos can be scored by users, thus providing comprehensive peer review of the site content. The site also supports multilingual narration\translation of videos, a quiz function for competence assessment and a library function allowing groups or institutions to define their standard operating procedures based on the video content. Results: The website went live in August 2013 and currently has over 680 registered users from 55 countries; 27.2% from the United States, 9.8% from India, 8.3% from the United Kingdom, 7.3% from Brazil, and 47.5% from other countries. The users include physicists (57.4%), Oncologists (12.5%), therapists (8.2%) and dosimetrists (4.8%). There are 75 videos to date including English, Portuguese, Mandarin, and Thai. Conclusion: Based on the initial acceptance of the site, we conclude that this open access web-based peer-to-peer tool is fulfilling an important need in radiotherapy training and education. Site functionality should expand in the future to include document sharing and continuing education credits.

61 RADIATION PROTECTION AND DOSIMETRY↗

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

TH-C-9A-01: Lean Tools and Methods

Lean thinking has revolutionized the manufacturing industry. Toyota has pioneered and leveraged this aspect of Lean thinking. Application of Lean thinking and Lean Six Sigma techniques into Healthcare and in particular in Radiation Oncology has its merits and challenges. To improve quality, safety and patient satisfaction with available resources or reducing cost in terms of time, staff and resources is demands of today's healthcare. Radiation oncology treatment involves many processes and steps, identifying and removing the non-value added steps in a process can significantly improve the efficiency. Real projects undertaken in radiation oncology department in cutting down the procedure time for MRI guided brachytherapy to 40% less using lean thinking will be narrated. Simple Lean tools and techniques such as Gemba walk, visual control, daily huddles, standard work, value stream mapping, error-proofing, etc. can be applied with existing resources and how that improved the operation in a Radiation Oncology department's two year experience will be discussed. Lean thinking focuses on identifying and solving the root-cause of a problem by asking “Why” and not “Who” and this requires a culture change of no blame. Role of leadership in building lean culture, employee empowerment and trains and develops lean thinkers will be presented. Why Lean initiatives fail and how to implement lean successfully in your clinic will be discussed. Learning Objectives: Concepts of lean management or lean thinking. Lean tools and techniques applied in Radiation Oncology. Implement no blame culture and focus on system and processes. Leadership role in implementing lean culture. Challenges for Lean thinking in healthcare.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2014

SU-E-J-221: Advantages of a New Surface Imaging Calibration Method for SRS Treatments

Purpose: The present calibration method used for the AlignRT surface imaging system relies on the placement of a calibration plate at the linac isocenter using isocenter surrogates (crosshairs, room lasers, etc.). This work investigated the potential advantages of a new calibration method that shifts the AlignRT isocenter to be coincident with the linac MV beam isocenter. Methods: To quantify the potential uncertainties associated with the present calibration method for SRS treatments, the calibration plate was intentionally shifted away from isocenter +/−3mm in the longitudinal and lateral directions and +/−1mm in the longitudinal, lateral, and vertical directions. A head phantom was placed in a mock SRS treatment position and monitored with the AlignRT system. The AlignRT-indicated offsets were recorded at 270, 315, 0, 45, and 90° couch angles for each intentional calibration misalignment. The new isocenter calibration was applied after each misalignment, and the measurements were repeated and compared to the previous results. Results: With intentional longitudinal and lateral shifts of +/−3mm and +/−1mm in the calibration plate, the average indicated offsets at couch rotations of +/−90° were 4.3mm and 1.6mm, respectively. This was in agreement with the theoretical offset of sqrt(2)*(intentional shift of the calibration plate). Since vertical shifts were along the rotation axis of the couch, these shifts had little effect on the offsets with changing couch angle. When the new calibration was applied, the indicated offsets were all within 0.5mm for all couch angles. These offsets were in agreement with the known magnitude of couch walkout. Conclusion: The potential pitfalls of the present calibration method have been established, and the advantages of the new calibration method have been demonstrated. This new calibration method effectively removes the potential miscalibration artifacts of the present calibration method, giving the AlignRT user more confidence in the system's indicated shifts.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗