T. Pawlicki

University of California, San Diego, San Diego, California, United States

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Publications (178)459.46 Total impact


  • No preview · Article · Nov 2015 · International journal of radiation oncology, biology, physics
  • Louis Potters · Eric Ford · Suzanne Evans · Todd Pawlicki · Sasa Mutic

    No preview · Article · Oct 2015 · International journal of radiation oncology, biology, physics
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    ABSTRACT: Purpose: The purpose of this study was 2-fold. One purpose was to develop an automated, streamlined quality assurance (QA) program for use by multiple centers. The second purpose was to evaluate machine performance over time for multiple centers using linear accelerator (Linac) log files and electronic portal images. The authors sought to evaluate variations in Linac performance to establish as a reference for other centers.
    No preview · Article · Oct 2015 · Medical Physics
  • Lawrence B Marks · Todd A Pawlicki · James Alan Hayman

    No preview · Article · Sep 2015 · Practical Radiation Oncology
  • Derek W. Brown · John Einck · Todd Pawlicki · Arno J. Mundt

    No preview · Article · Sep 2015 · International journal of radiation oncology, biology, physics
  • G Kim · R Manger · T Pawlicki
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    ABSTRACT: Failure Modes and Effects Analysis (FMEA) techniques have been used to analyze surface image guided radiosurgery (SIG-RS). Hazard model, a modified FMEA approach developed by the Dutch, is applied to SIG-RS risk assessment and evaluated against the AAPM's FMEA approach. The SAFER approach uses a risk inventory matrix to categorize hazards (rather than probabilities). A multidisciplinary team was assembled to create the process map of SIG-RS and 91 steps and 167 failure modes were determined. Each failure mode was categorized for frequency (weekly, monthly, quarterly, yearly and less than once a year) and severity (negligible, minor, moderate, major and catastrophic) according to the SAFER procedures. All failure modes are placed in the matrix of arbitrary risk score matrix: very high, high, low, and very low. The top 14 high risk failure modes from the Result of FMEA and SAFER analysis were compared. 167 failure modes categorized in the risk inventory matrix with 1 very high, 13 high, 66 low and 87 very low. Comparison of top 14 high risk failure modes between two techniques shows 9 common failure modes and 5 isolated failure modes. Two failure modes (FM: 58, 145) with the highest risk priority number (both RPN=288) in FMEA are also ranked as high risk in SAFER analysis. However one failure mode (FM: 154) with very high risk score in SAFER is not recognized by FMEA analysis due to its low "lack of detectability" score. FMEA is a well-established technique for prospective risk analysis. SAFER is a practical alternative that is easy to implement with a reliable category structure. Also the risk inventory matrix is conceptually straightforward to obtain agreement among multidisciplinary team members but still demonstrates a full scale of criticality.
    No preview · Article · Jun 2015 · Medical Physics
  • R Manger · T Pawlicki · G Kim
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    ABSTRACT: 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. 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. 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. 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.
    No preview · Article · Jun 2015 · Medical Physics
  • T Harry · S Yaddanapudi · B Cai · S Goddu · C Noel · S Mutic · T Pawlicki
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    ABSTRACT: 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. 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. 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. 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.
    No preview · Article · Jun 2015 · Medical Physics
  • S Yaddanapudi · B Cai · T Harry · B Sun · H Li · C Noel · S Goddu · T Pawlicki · S Mutic
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    ABSTRACT: 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. 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. 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. 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.
    No preview · Article · Jun 2015 · Medical Physics
  • D Zaks · R Fletcher · S Salamon · G Kim · T Ning · M Cornell · T Pawlicki · L Cervino
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    ABSTRACT: 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. 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. 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. 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.
    No preview · Article · Jun 2015 · Medical Physics
  • Ryan P. Manger · Adam B. Paxton · Todd Pawlicki · Gwe-Ya Kim
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    ABSTRACT: Purpose: Surface image guided, Linac-based radiosurgery (SIG-RS) is a modern approach for delivering radiosurgery that utilizes optical stereoscopic imaging to monitor the surface of the patient during treatment in lieu of using a head frame for patient immobilization. Considering the novelty of the SIG-RS approach and the severity of errors associated with delivery of large doses per fraction, a risk assessment should be conducted to identify potential hazards, determine their causes, and formulate mitigation strategies. The purpose of this work is to investigate SIG-RS using the combined application of failure modes and effects analysis (FMEA) and fault tree analysis (FTA), report on the effort required to complete the analysis, and evaluate the use of FTA in conjunction with FMEA.
    No preview · Article · May 2015 · Medical Physics
  • Todd Pawlicki · Louis Potters

    No preview · Article · Apr 2015 · International journal of radiation oncology, biology, physics
  • Shannon Fogh · Todd Pawlicki

    No preview · Article · Dec 2014 · International journal of radiation oncology, biology, physics
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    ABSTRACT: Purpose To report on the use of an incident learning system in a radiation oncology clinic, along with a review of staff participation. Methods and Materials On September 24, 2010, our department initiated an online real-time voluntary reporting system for safety issues, called the Radiation Oncology Quality Reporting System (ROQRS). We reviewed these reports from the program's inception through January 18, 2013 (2 years, 3 months, 25 days) to assess error reports (defined as both near-misses and incidents of inaccurate treatment). Results During the study interval, there were 60,168 fractions of external beam radiation therapy and 955 brachytherapy procedures. There were 298 entries in the ROQRS system, among which 108 errors were reported. There were 31 patients with near-misses reported and 27 patients with incidents of inaccurate treatment reported. These incidents of inaccurate treatment occurred in 68 total treatment fractions (0.11% of treatments delivered during the study interval). None of these incidents of inaccurate treatment resulted in deviation from the prescription by 5% or more. A solution to the errors was documented in ROQRS in 65% of the cases. Errors occurred as repeated errors in 22% of the cases. A disproportionate number of the incidents of inaccurate treatment were due to improper patient setup at the linear accelerator (P<.001). Physician participation in ROQRS was nonexistent initially, but improved after an education program. Conclusions Incident learning systems are a useful and practical means of improving safety and quality in patient care.
    No preview · Article · Oct 2014 · International journal of radiation oncology, biology, physics
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    ABSTRACT: To track linear accelerator performance issues, an online event recording system was developed in-house for use by therapists and physicists to log the details of technical problems arising on our institution's four linear accelerators. In use since October 2010, the system was designed so that all clinical physicists would receive email notification when an event was logged. Starting in October 2012, we initiated a pilot project in collaboration with our linear accelerator vendor to explore a new model of service and support, in which event notifications were also sent electronically directly to dedicated engineers at the vendor's technical help desk, who then initiated a response to technical issues. Previously, technical issues were reported by telephone to the vendor's call center, which then disseminated information and coordinated a response with the Technical Support help desk and local service engineers. The purpose of this work was to investigate the improvements to clinical operations resulting from this new service model. The new and old service models were quantitatively compared by reviewing event logs and the oncology information system database in the nine months prior to and after initiation of the project. Here, we focus on events that resulted in an inoperative linear accelerator ("down" machine). Machine downtime, vendor response time, treatment cancellations, and event resolution were evaluated and compared over two equivalent time periods. In 389 clinical days, there were 119 machine-down events: 59 events before and 60 after introduction of the new model. In the new model, median time to service response decreased from 45 to 8 min, service engineer dispatch time decreased 44%, downtime per event decreased from 45 to 20 min, and treatment cancellations decreased 68%. The decreased vendor response time and reduced number of on-site visits by a service engineer resulted in decreased downtime and decreased patient treatment cancellations.
    No preview · Article · Sep 2014 · Journal of Applied Clinical Medical Physics
  • A Paxton · R Manger · T Pawlicki · G Kim
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    ABSTRACT: 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.
    No preview · Article · Jun 2014 · Medical Physics
  • T Pawlicki · D Brown · P Dunscombe · S Mutic
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    ABSTRACT: 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.
    No preview · Article · Jun 2014 · Medical Physics
  • R Manger · A Paxton · T Pawlicki · G Kim
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    ABSTRACT: Purpose: To develop a process map detailing the steps in the clinical workflow for surface imaging guided stereotactic radiosurgery (SRS), conduct a failure mode and effects analysis (FMEA) based on the process map, and perform fault tree analysis (FTA) on the steps with the highest risk priority number (RPN).
    No preview · Article · Jun 2014 · Medical Physics
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    ABSTRACT: To analyze the implementation of a passive radiofrequency identification (RFID) clinical system and to evaluate the clinical workflow on 2 linear accelerators using the RFID technology. The clinical area of a typical radiation therapy center was equipped with RFID readers and antennae, which included linear accelerator (linac) treatment vaults. Both were dual energy linacs (6 and 15 MV). One linac was an iX with RapidArc (Varian Medical Systems, Inc, Palo Alto, CA) and the other was a TrueBeam (Varian Medical Systems, Inc, Palo Alto, CA). Patients were given an RFID transponder card on their first day of treatment. Location timestamps were collected when the patients entered and exited the linac vaults. Each fraction was categorized by treatment machine, treatment site (brain, head and neck, prostate, and other), and treatment type (static field intensity modulated radiation therapy [IMRT], RapidArc, and 3-dimensional [3D]). The Mann-Whitney nonparametric test was used to determine statistical significance between median times in the linac vault. A total of 4302 fractions from 144 patients were analyzed over a 10-month period. With minimal staff training, an approximately 70% read reliability was achieved. The median treatment time for all treatment fractions on the TrueBeam linac was 11.0 minutes (n = 1425) while the median time was 11.9 minutes (n = 1576) on the iX linac (P < .0001). Median times for the RapidArc cases was 10.9 minutes (n = 610) and 12.0 minutes (n = 1729) for IMRT cases (P < .0001). Median values for 3D delivery versus modulated delivery (RapidArc and IMRT) were 9.8 minutes (n = 315) and 11.7 minutes (n = 2339), P < .0001. Automatic remote reading of passive transponder cards is not without its challenges. However, with little or no clinical introduction, we experienced a read reliability that warrants further development. Our initial use of the system indicates that continual collection and analysis of workflow data may allow clinics to improve efficiency and safety.
    No preview · Article · Mar 2014 · Practical Radiation Oncology
  • D.A. Rahn · G.G. Kim · T. Pawlicki · A.J. Mundt

    No preview · Article · Oct 2013 · International Journal of Radiation OncologyBiologyPhysics

Publication Stats

2k Citations
459.46 Total Impact Points

Institutions

  • 2007-2015
    • University of California, San Diego
      • Department of Radiation Oncology
      San Diego, California, United States
  • 2014
    • University of San Diego
      San Diego, California, United States
  • 2013
    • Chulalongkorn University
      • Department of Nuclear Technology
      Siayuthia, Bangkok, Thailand
  • 2011
    • Spokane VA Medical Center
      Spokane, Washington, United States
  • 2010
    • University of Wisconsin–Madison
      • Department of Human Oncology
      Madison, Wisconsin, United States
  • 1999-2008
    • Stanford Medicine
      • Department of Radiation Oncology
      Stanford, California, United States
  • 2000-2006
    • Stanford University
      • • Department of Radiation Oncology
      • • Department of Medicine
      Palo Alto, California, United States
  • 2004
    • Fox Chase Cancer Center
      Philadelphia, Pennsylvania, United States
  • 1994-1997
    • Medical University of Ohio at Toledo
      Toledo, Ohio, United States
  • 1994-1996
    • West Virginia University
      • Department of Radiology
      MGW, West Virginia, United States