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Automating QA analysis for a six-degree-of-freedom (6DOF) couch using image displacement and an accelerometer sensor. Phys Med 2022; 101:129-136. [PMID: 35998433 DOI: 10.1016/j.ejmp.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 06/13/2022] [Accepted: 08/04/2022] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study is to develop an approach for automating quality assurance (QA) analysis for a six-degree-of-freedom (6DOF) couch using image displacement and an accelerometer sensor. A cubic phantom was fabricated using 3D printing and the accelerometer sensor was embedded in the phantom to measure the couch in the pitch and roll directions. The accuracy and reliability of image displacement and the accelerometer sensor were investigated prior to their practical use for 6DOF couch QA. Image displacement performance had an accuracy and reliability of 0.026 ± 0.026 mm for the translation direction and 0.021 ± 0.016° for the rotation direction. Accelerometer sensor performance had an accuracy and reliability of 0.023 ± 0.018° for pitch rotation and 0.051 ± 0.024° for roll rotation. Automating QA analysis was used to perform 6DOF couch QA, and the couch position errors measured using image displacement were less than 0.99 mm, 0.91 mm, 0.82 mm for the vertical, longitudinal, lateral translation in range between ±20 mm, and 0.07°, 0.23°, and 0.2° for pitch, roll, and yaw rotation in range between ±3° whereas the couch position errors measured using the accelerometer sensor were less than 0.1° and 0.19° for the pitch and roll rotation in range between ±3°.
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Descriptive Time Series Analysis for Downtime Prediction Using the Maintenance Data of a Medical Linear Accelerator. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12115431] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A medical linear accelerator (LINAC) delivers high-energy X-rays or electrons to the patient’s tumor. In this study, we categorized failures and predicted downtime leading to discontinuous radiation treatment using a descriptive time series analysis of a 20-year maintenance dataset of a medical LINAC. A LINAC dataset of failure records for 359 instances was collected from 2001 to 2021. Next, we performed institution-specific seasonal autoregressive integrated moving average (ARIMA) modeling to analyze the causes of the failure categories and predict the downtime. Furthermore, we evaluated the performance of the predictive model using standard error metrics and statistical methods. Our results show that the downtime will increase by 95 h/year after 2022 and 100 h/year after 2023. The accumulated downtime in 2029 is predicted to be a maximum of 2820 h. The modeled seasonal ARIMA showed statistical significance (p < 0.001) with a residual error of σ2 (328.33 ± 9.4). In addition, the forecasting performance of the model was assessed using the mean absolute percentage error (MAPE). The failure parts where the major downtime occurred were the multileaf collimator (25.2%), gantry and couch motion part (15.4%), dosimetric part (11.7%), and computer console (10.0%). Using the development of the ARIMA model specific to our institution, the downtime is predicted to reach up to 2820 h.
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Barnes MP, Sun B, Oborn BM, Lamichhane B, Szwec S, Schmidt M, Cai B, Menk F, Greer P. Determination of the electronic portal imaging device pixel‐sensitivity‐map for quality assurance applications. Part 2: Photon beam dependence. J Appl Clin Med Phys 2022; 23:e13602. [PMID: 35429117 PMCID: PMC9195019 DOI: 10.1002/acm2.13602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/08/2022] [Accepted: 03/15/2022] [Indexed: 11/08/2022] Open
Abstract
Purpose Methods Results Conclusion
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Affiliation(s)
- Michael Paul Barnes
- Department of Radiation Oncology Calvary Mater Hospital Newcastle Newcastle NSW Australia
- School of Mathematical and Physical Sciences University of Newcastle Newcastle NSW Australia
| | - Baozhou Sun
- Department of Radiation Oncology Washington University in St Louis St Louis Missouri USA
| | - Brad Michael Oborn
- Centre for Medical Radiation Physics University of Wollongong Wollongong NSW Australia
- Illawarra Cancer Care Centre Wollongong Hospital Wollongong NSW Australia
| | - Bishnu Lamichhane
- School of Mathematical and Physical Sciences University of Newcastle Newcastle NSW Australia
| | - Stuart Szwec
- School of Medicine and Public Health University of Newcastle Newcastle NSW Australia
| | - Matthew Schmidt
- Department of Radiation Oncology Washington University in St Louis St Louis Missouri USA
| | - Bin Cai
- Department of Radiation Oncology Washington University in St Louis St Louis Missouri USA
| | - Frederick Menk
- School of Mathematical and Physical Sciences University of Newcastle Newcastle NSW Australia
| | - Peter Greer
- Department of Radiation Oncology Calvary Mater Hospital Newcastle Newcastle NSW Australia
- School of Mathematical and Physical Sciences University of Newcastle Newcastle NSW Australia
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Barnes MP, Sun B, Oborn BM, Lamichhane B, Szwec S, Schmidt M, Cai B, Menk F, Greer P. Determination of the electronic portal imaging device pixel‐sensitivity‐map for quality assurance applications. Part 1: Comparison of methods. J Appl Clin Med Phys 2022; 23:e13603. [PMID: 35429102 PMCID: PMC9195035 DOI: 10.1002/acm2.13603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 03/08/2022] [Accepted: 03/15/2022] [Indexed: 11/06/2022] Open
Abstract
Purpose Methods Results Conclusion
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Affiliation(s)
- Michael Paul Barnes
- Department of Radiation Oncology Calvary Mater Hospital Newcastle Newcastle New South Wales Australia
- School of Mathematical and Physical Sciences University of Newcastle Newcastle New South Wales Australia
| | - Baozhou Sun
- Department of Radiation Oncology Washington University in St. Louis St. Louis Missouri USA
| | - Brad Michael Oborn
- Centre for Medical Radiation Physics University of Wollongong Wollongong New South Wales Australia
- Illawarra Cancer Care Centre Wollongong Hospital Wollongong New South Wales Australia
| | - Bishnu Lamichhane
- School of Mathematical and Physical Sciences University of Newcastle Newcastle New South Wales Australia
| | - Stuart Szwec
- School of Medicine and Public Health University of Newcastle Newcastle New South Wales Australia
| | - Matthew Schmidt
- Department of Radiation Oncology Washington University in St. Louis St. Louis Missouri USA
| | - Bin Cai
- Department of Radiation Oncology Washington University in St. Louis St. Louis Missouri USA
| | - Frederick Menk
- School of Mathematical and Physical Sciences University of Newcastle Newcastle New South Wales Australia
| | - Peter Greer
- Department of Radiation Oncology Calvary Mater Hospital Newcastle Newcastle New South Wales Australia
- School of Mathematical and Physical Sciences University of Newcastle Newcastle New South Wales Australia
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Renaud J, Muir B. Assessing the accuracy of electronic portal imaging device (EPID)-based dosimetry: I. Quantities influencing long-term stability. Med Phys 2021; 49:1231-1237. [PMID: 34964136 DOI: 10.1002/mp.15434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 12/08/2021] [Accepted: 12/12/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The aim of this study is to reduce the uncertainty associated with determining dose-to-water using an amorphous silicon electronic portal imaging detector (EPID) under reference conditions by identifying and accounting for operational and environmental factors influencing long-term stability of EPID response. METHODS Measurements of the EPID relative response, corrected for variations in linear accelerator (linac) output, were performed regularly over a period of 12 months. For every acquired image set, measurements of detector supply voltages, internal operating temperature, and ambient environmental conditions were obtained. Pearson r correlation coefficients were then calculated for each pair of variables, a subset of which were fitted using multiple linear regression to develop a predictive model of EPID response. Principal component analysis was performed on the dataset to reveal the internal structure of the data in a way that best accounts for the observed variations. RESULTS The +5.5 V power supply voltage, internal operating temperature, and the accumulated dose absorbed in EPID were identified as having the greatest influence on the long-term stability of EPID response. By correcting for the combined effect of these variables, the mean difference in linac output as measured by the EPID relative to a reference-class chamber improved from -0.46 % to 0.23 % over the period of the study. CONCLUSIONS This work suggests that the stability of an EPID over a period of a year can be improved by a factor of two by monitoring and accounting for the effects of variations in power supply voltage, internal temperature of the detector, and accumulated absorbed dose. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- James Renaud
- Metrology Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Bryan Muir
- Metrology Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
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Renaud J, Muir B. Assessing the accuracy of electronic portal imaging device (EPID)-based dosimetry: II. Evaluation of a dosimetric uncertainty budget and development of a new film-in-EPID absorbed dose calibration methodology. Med Phys 2021; 49:1238-1247. [PMID: 34954834 DOI: 10.1002/mp.15425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/12/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The aim of this study is to reduce the uncertainty associated with determining dose-to-water using an amorphous silicon electronic portal imaging detector (EPID) under reference conditions by developing a direct calibration formalism based on radiochromic film measurements made within the EPID panel and detailed Monte Carlo simulations. To our knowledge, this is the first EPID-based dosimetry study reporting an uncertainty budget . METHODS Pixel sensitivity and relative off-axis response was mapped by simultaneously irradiating film contained within the imager panel and acquiring an EPID image set. The detector panel was disassembled for the purpose of modeling the EPID in detail using the EGSnrc DOSXYZnrc usercode, which was in turn used to calculate dose-to-film in EPID to dose-to-water in water conversion factors . RESULTS A direct comparison of the two correction methodologies investigated in this work, the previously established empirical method and the proposed simultaneous measurement approach involving in-EPID film dosimetry, produced an agreement with an RMS deviation of 1.4 % overall. A combined standard relative uncertainty of 3.3 % (k = 1) was estimated for the determination of absorbed dose to water at the position of the EPID using the proposed calibration methodology . CONCLUSIONS This work describes a direct method of calibrating EPID response in terms of absorbed dose to water requiring fewer measurements than other empirical approaches, and without 2D spatial interpolation of correction factors. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- James Renaud
- Metrology Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Bryan Muir
- Metrology Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
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Schmidt MC, Raman CA, Wu Y, Yaqoub MM, Hao Y, Mahon RN, Riblett MJ, Knutson NC, Sajo E, Zygmanski P, Jandel M, Reynoso FJ, Sun B. Application programming interface guided QA plan generation and analysis automation. J Appl Clin Med Phys 2021; 22:26-34. [PMID: 34036736 PMCID: PMC8200500 DOI: 10.1002/acm2.13288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/15/2021] [Accepted: 04/23/2021] [Indexed: 11/11/2022] Open
Abstract
Purpose Linear accelerator quality assurance (QA) in radiation therapy is a time consuming but fundamental part of ensuring the performance characteristics of radiation delivering machines. The goal of this work is to develop an automated and standardized QA plan generation and analysis system in the Oncology Information System (OIS) to streamline the QA process. Methods Automating the QA process includes two software components: the AutoQA Builder to generate daily, monthly, quarterly, and miscellaneous periodic linear accelerator QA plans within the Treatment Planning System (TPS) and the AutoQA Analysis to analyze images collected on the Electronic Portal Imaging Device (EPID) allowing for a rapid analysis of the acquired QA images. To verify the results of the automated QA analysis, results were compared to the current standard for QA assessment for the jaw junction, light‐radiation coincidence, picket fence, and volumetric modulated arc therapy (VMAT) QA plans across three linacs and over a 6‐month period. Results The AutoQA Builder application has been utilized clinically 322 times to create QA patients, construct phantom images, and deploy common periodic QA tests across multiple institutions, linear accelerators, and physicists. Comparing the AutoQA Analysis results with our current institutional QA standard the mean difference of the ratio of intensity values within the field‐matched junction and ball‐bearing position detection was 0.012 ± 0.053 (P = 0.159) and is 0.011 ± 0.224 mm (P = 0.355), respectively. Analysis of VMAT QA plans resulted in a maximum percentage difference of 0.3%. Conclusion The automated creation and analysis of quality assurance plans using multiple APIs can be of immediate benefit to linear accelerator quality assurance efficiency and standardization. QA plan creation can be done without following tedious procedures through API assistance, and analysis can be performed inside of the clinical OIS in an automated fashion.
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Affiliation(s)
- Matthew C Schmidt
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA.,Department of Physics, University of Massachusetts Lowell, Lowell, MA, USA
| | - Caleb A Raman
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yu Wu
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Mahmoud M Yaqoub
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yao Hao
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Rebecca Nichole Mahon
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Matthew J Riblett
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nels C Knutson
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Erno Sajo
- Department of Physics, University of Massachusetts Lowell, Lowell, MA, USA
| | - Piotr Zygmanski
- Brigham and Women's/ Dana Farber Cancer Institute/ Harvard Medical School, Boston, MA, USA
| | - Marian Jandel
- Department of Physics, University of Massachusetts Lowell, Lowell, MA, USA
| | - Francisco J Reynoso
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Baozhou Sun
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
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Bayatiani MR, Fallahi F, Aliasgharzadeh A, Ghorbani M, Khajetash B, Seif F. A comparison of symmetry and flatness measurements in small electron fields by different dosimeters in electron beam radiotherapy. Rep Pract Oncol Radiother 2021; 26:50-58. [PMID: 33948302 DOI: 10.5603/rpor.a2021.0009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 12/23/2020] [Indexed: 11/25/2022] Open
Abstract
Background Symmetry and flatness are two quantities which should be evaluated in the commissioning and quality control of an electron beam in electron beam radiotherapy. The aim of this study is to compare symmetry and flatness obtained using three different dosimeters for various small and large fields in electron beam radiotherapy with linac. Materials and methods Beam profile measurements were performed in a PTW water phantom for 10, 15 and 18 MeV electron beams of an Elekta Precise linac for small and large beams (1.5 × 1.5 cm2 to 20 × 20 cm2 field sizes). A Diode E detector and Semiflex-3D and Advanced Markus ionization chambers were used for dosimetry. Results Based on the obtained results, there are minor differences between the responses from different dosimeters (Diode E detector and Semiflex-3D and Advanced Markus ionization chambers) in measurement of symmetry and flatness for the electron beams. The symmetry and flatness values increase with increasing field size and electron beam energy for small and large field sizes, while the increases are minor in some cases. Conclusions The results indicate that the differences between the symmetry and flatness values obtained from the three dosimeter types are not practically important.
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Affiliation(s)
- Mohamad Reza Bayatiani
- Medical Physics and Radiotherapy Department, School of Paramedical Sciences, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
| | - Fatemeh Fallahi
- Department of Medical Physics, School of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran
| | - Akbar Aliasgharzadeh
- Department of Medical Physics, School of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran
| | - Mahdi Ghorbani
- Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Benyamin Khajetash
- Medical Physics Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Seif
- Medical Physics and Radiotherapy Department, School of Paramedical Sciences, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
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Hao Y, Cai B, Green O, Knutson N, Yaddanapudi S, Zhao T, Rodriguez V, Schmidt M, Mutic S, Sun B. Technical Note: An alternative approach to verify 6FFF beam dosimetry for Ethos and MR Linac without using a 3D water tank. Med Phys 2021; 48:1533-1539. [PMID: 33547684 DOI: 10.1002/mp.14757] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/17/2020] [Accepted: 01/29/2021] [Indexed: 12/24/2022] Open
Abstract
PURPOSE The current approach to Linac beam dosimetry verification is typically performed utilizing a three-dimensional (3D) water tank system. The 3D beam scanning process is cumbersome, labor intensive, error-prone, and costly. This is especially challenging for the new Ethos system and MR Linacs with a ring gantry. This work proposes an alternative approach to verify 6FFF beam dosimetry for Ethos, ViewRay MRIdian® Linac, and other Linacs with 6FFF beam quality using two-dimensional (2D) ion chamber arrays. METHODS Percentage depth dose (PDD) and profiles of an Ethos, an MRIdian® Linac, and several Linacs with 6FFF beams were measured at the nominal beam current. The beam energy was detuned by changing the bending magnet current on one TrueBeam. PDDs and profiles were measured for detuned beam energies. The peak shape of the 6FFF profile was defined by a "slope" parameter and unflatness. Correlations between peak slope and unflatness metrics vs PDDs were used to evaluate the sensitivity of beam energy to beam profile changes at different field sizes and depths. RESULTS Strong correlations were found between peak slope and PDDs for all Linacs with 6FFF beam. The R-squared values in the linear regression fitting between PDD and peak slope and unflatness were 0.99 and 0.84, respectively. Both profile slope and unflatness were proportional to PDD at the 10 cm depth and the peak slope was 4.3 times more sensitive than PDD. We have identified that measurements with a shallow depth are preferred to quantify the beam energy consistency. CONCLUSIONS Our work shows the feasibility of verifying 6FFF beam quality of Ethos, MR Linac, and other Linacs by defining a profile slope measured from 2D ionization chambers array devices. This new approach provides a simplified method for performing a routine beam quality check without using a 3D water tank system while maximizing cost effectiveness and efficiency.
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Affiliation(s)
- Yao Hao
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Bin Cai
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Olga Green
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Nels Knutson
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Sridhar Yaddanapudi
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, LL-W Pomerantz Family Pavilion, Iowa City, IA, 52242-1089, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Vivian Rodriguez
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Matthew Schmidt
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Sasa Mutic
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Baozhou Sun
- Department of Radiation Oncology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
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Mittauer KE, Yadav P, Paliwal B, Bayouth JE. Characterization of positional accuracy of a double‐focused and double‐stack multileaf collimator on an MR‐guided radiotherapy (MRgRT) Linac using an IC‐profiler array. Med Phys 2019; 47:317-330. [DOI: 10.1002/mp.13902] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 11/07/2022] Open
Affiliation(s)
- Kathryn E. Mittauer
- Department of Radiation Oncology Miami Cancer Institute Baptist Health South Florida Miami FL USA
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
| | - Poonam Yadav
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
| | - Bhudatt Paliwal
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
| | - John E. Bayouth
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
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Kang H, Patel R, Roeske JC. Efficient quality assurance method with automated data acquisition of a single phantom setup to determine radiation and imaging isocenter congruence. J Appl Clin Med Phys 2019; 20:127-133. [PMID: 31535781 PMCID: PMC6806465 DOI: 10.1002/acm2.12723] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 07/22/2019] [Accepted: 08/27/2019] [Indexed: 12/31/2022] Open
Abstract
We developed a quality assurance (QA) method to determine the isocenter congruence of Optical Surface Monitoring System (OSMS, Varian, CA, USA), kilovoltage (kV), and megavoltage (MV) imaging, and the radiation isocenter using a single setup of the OSMS phantom for frameless Stereotactic Radiosurgery (SRS) treatment. After aligning the phantom to the OSMS isocenter, a cone‐beam computed tomography (CBCT) of the phantom was acquired and registered to a computed tomography (CT) scan of the phantom to determine the CBCT isocenter. Without moving the phantom, MV and kV images were simultaneously acquired at four gantry angles to localize MV and kV isocenters. Then, Winston‐Lutz (W‐L) test images of the central BB in the phantom were acquired to analyze the radiation isocenter. The gantry and couch were automatically controlled using the TrueBeam Developer Mode during MV, kV, and W‐L image acquisition. All the images were acquired weekly for 17 weeks to track the congruence of all the imaging modalities' isocenter in six‐dimensional (6D) translations and rotations, and the radiation isocenter in three‐dimensional (3D) translations. The shifts of isocenters of all imaging modalities and the radiation isocenter from the OSMS isocenter were within 0.2 mm and 0.2° on average over 17 weeks. The maximum discrepancy between OSMS and other imaging modalities or radiation isocenters was 0.8 mm and 0.3°. However, systematic shifts of radiation isocenter anteriorly and laterally relative to the OSMS isocenter were observed. The measured discrepancies were consistent from week‐to‐week except for two weeks when the isocenter discrepancies of 0.8 mm were noted due to drifts of the OSMS isocenter. Once recalibration was performed on OSMS, the discrepancy was reduced to 0.3 mm and 0.2°.By performing the proposed QA on a weekly basis, the isocenter congruencies of multiple imaging systems and radiation isocenter were validated for a linear accelerator.
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Affiliation(s)
- Hyejoo Kang
- Department of Radiation Oncology, Loyola Medicine, Maywood, IL, USA
| | - Rakesh Patel
- Department of Radiation Oncology, Loyola Medicine, Maywood, IL, USA
| | - John C Roeske
- Department of Radiation Oncology, Loyola Medicine, Maywood, IL, USA
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12
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Teo PT, Hwang MS, Shields WG, Kosterin P, Jang SY, Heron DE, Lalonde RJ, Huq MS. Application of TG-100 risk analysis methods to the acceptance testing and commissioning process of a Halcyon linear accelerator. Med Phys 2019; 46:1341-1354. [PMID: 30620406 DOI: 10.1002/mp.13378] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/25/2018] [Accepted: 12/17/2018] [Indexed: 11/08/2022] Open
Abstract
PURPOSE A new type of linear accelerator (linac) was recently introduced into the market by a major manufacturer. Our institution is one of the early users of this preassembled and preconfigured dual-layer multileaf collimator (MLC), ring-gantry linac - Halcyon™ (1st version). We performed a set of full acceptance testing and commissioning (ATC) measurements for three Halcyon machines and compared the measured data with the standard beam model provided by the manufacturer. The ATC measurements were performed following the guidelines given in different AAPM protocols as well as guidelines provided by the manufacturer. The purpose of the present work was to perform a risk assessment of the ATC process for this new type of linac and investigate whether the results obtained from this analysis could potentially be used as a guideline for improving the design features of this type of linac. METHODS AAPM's TG100 risk assessment methodology was applied to the ATC process. The acceptance testing process relied heavily on the use of a manufacturer-supplied phantom and the automated analysis of electronic portal imaging device (EPID) images. For the commissioning process, a conventional measurement setup and process (e.g., use of water tank for scanning) was largely used. ATC was performed using guidelines recommended in various AAPM protocols (e.g., TG-106, TG-51) as well as guidelines provided by the manufacturer. Six medical physicists were involved in this study. Process maps, process steps, and failure modes (FMs) were generated for the ATC procedures. Failure modes and effects analysis (FMEA) were performed following the guidelines given in AAPM TG-100 protocol. The top 5 and top 10 highest-ranked FMs were identified for the acceptance and commissioning procedures, respectively. Quality control measures were suggested to mitigate these FMs. RESULTS A total of 38 steps and 88 FMs were identified for the entire ATC process. Fourteen steps and 34 FMs arose from acceptance testing. The top 5 FMs that were identified could potentially be mitigated by the manufacturer. For commissioning, a total of 24 steps and 54 potential FMs were identified. The use of separate measurement tools that are not machine-integrated has been identified as a cause for the higher number of steps and FMs generated from the conventional ATC approach. More than half of the quality control measures recommended for both acceptance and commissioning could potentially be incorporated by the manufacturer in the design of the Halcyon machine. CONCLUSION This paper presents the results of FMEA and quality control measures to mitigate the FMs for the ATC process for Halcyon machine. Unique FMs that result from the differences in the ATC guidelines provided by the vendor and current conventional protocols, and the challenges of performing the ATC due to the new linac features and ring-gantry design were highlighted for the first time. The FMs identified in the present work along with the suggested quality control measures, could potentially be used to improve the design features of future ring-gantry type of linacs that are likely to be preassembled, preconfigured, and heavily reliant on automation and image guidance.
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Affiliation(s)
- P Troy Teo
- Division of Medical Physics, Department of Radiation Oncology, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Min-Sig Hwang
- Division of Medical Physics, Department of Radiation Oncology, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | | | - Pavel Kosterin
- Division of Medical Physics, Department of Radiation Oncology, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Si Young Jang
- Division of Medical Physics, Department of Radiation Oncology, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Dwight E Heron
- Division of Medical Physics, Department of Radiation Oncology, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Ronald J Lalonde
- Division of Medical Physics, Department of Radiation Oncology, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - M Saiful Huq
- Division of Medical Physics, Department of Radiation Oncology, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, PA, USA
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13
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Cai B, He Y, Bollinger D, Li H, Goddu SM, Mutic S, Sun B. Three year experience of electronic portal imaging device based daily QA for photon radiation beams. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aae419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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Knutson NC, Schmidt MC, Belley MD, Nguyen N, Price M, Mutic S, Sajo E, Li HH. Equivalency of beam scan data collection using a 1D tank and automated couch movements to traditional 3D tank measurements. J Appl Clin Med Phys 2018; 19:60-67. [PMID: 30188009 PMCID: PMC6236829 DOI: 10.1002/acm2.12444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 07/16/2018] [Accepted: 08/04/2018] [Indexed: 12/18/2022] Open
Abstract
This work shows the feasibility of collecting linear accelerator beam data using just a 1‐D water tank and automated couch movements with the goal to maximize the cost effectiveness in resource‐limited clinical settings. Two commissioning datasets were acquired: (a) using a standard of practice 3D water tank scanning system (3DS) and (b) using a novel technique to translate a commercial TG‐51 complaint 1D water tank via automated couch movements (1DS). The Extensible Markup Language (XML) was used to dynamically move the linear accelerator couch position (and thus the 1D tank) during radiation delivery for the acquisition of inline, crossline, and diagonal profiles. Both the 1DS and 3DS datasets were used to generate beam models (BM1DS and BM3DS) in a commercial treatment planning system (TPS). 98.7% of 1DS measured points had a gamma value (2%/2 mm) < 1 when compared with the 3DS. Static jaw defined field and dynamic MLC field dose distribution comparisons for the TPS beam models BM1DS and BM3DS had 3D gamma values (2%/2 mm) < 1 for all 24,900,000 data points tested and >99.5% pass rate with gamma value (1%/1 mm) < 1. In conclusion, automated couch motions and a 1D scanning tank were used to collect commissioning beam data with accuracy comparable to traditionally acquired data using a 3D scanning system. TPS beam models generated directly from 1DS measured data were clinically equivalent to a model derived from 3DS data.
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Affiliation(s)
- Nels C Knutson
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA.,Medical Physics Program, University of Massachusetts Lowell, Lowell, MA, 01852, USA.,Department of Radiation Oncology, Rhode Island Hospital, The Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | - Matthew C Schmidt
- Medical Physics Program, University of Massachusetts Lowell, Lowell, MA, 01852, USA.,Department of Radiation Oncology, Rhode Island Hospital, The Alpert Medical School of Brown University, Providence, RI, 02903, USA.,Education Department, Varian Medical Systems, Las Vegas, NV, 89119, USA
| | - Matthew D Belley
- Department of Radiation Oncology, Rhode Island Hospital, The Alpert Medical School of Brown University, Providence, RI, 02903, USA.,Department of Physics, University of Rhode Island, Kingston, RI, 02881, USA
| | - Ngoc Nguyen
- Department of Radiation Oncology, Rhode Island Hospital, The Alpert Medical School of Brown University, Providence, RI, 02903, USA.,Department of Physics, University of Rhode Island, Kingston, RI, 02881, USA
| | - Michael Price
- Department of Radiation Oncology, Rhode Island Hospital, The Alpert Medical School of Brown University, Providence, RI, 02903, USA.,Department of Physics, University of Rhode Island, Kingston, RI, 02881, USA
| | - Sasa Mutic
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Erno Sajo
- Medical Physics Program, University of Massachusetts Lowell, Lowell, MA, 01852, USA
| | - H Harold Li
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA
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15
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Barnes MP, Menk FW, Lamichhane BP, Greer PB. A proposed method for linear accelerator photon beam steering using EPID. J Appl Clin Med Phys 2018; 19:591-597. [PMID: 30047209 PMCID: PMC6123104 DOI: 10.1002/acm2.12419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 05/11/2018] [Accepted: 06/29/2018] [Indexed: 11/30/2022] Open
Abstract
Beam steering is the process of calibrating the angle and translational position with which a linear accelerator's (linac's) electron beam strikes the x‐ray target with respect to the collimator rotation axis. The shape of the dose profile is highly dependent on accurate beam steering and is essential for ensuring correct delivery of the radiotherapy treatment plan. Traditional methods of beam steering utilize a scanning water tank phantom that makes the process user‐dependent. This study is the first to provide a methodology for both beam angle steering and beam translational position steering based on EPID imaging of the beam and does not require a phantom. Both the EPID‐based beam angle steering and beam translational steering methods described have been validated against IC Profiler measurement. Wide field symmetry agreement was found between the EPID and IC Profiler to within 0.06 ± 0.14% (1 SD) and 0.32 ± 0.11% (1 SD) for flattened and flattening‐filter‐free (FFF) beams, respectively. For a 1.1% change in symmetry measured by IC Profiler the EPID method agreed to within 0.23%. For beam translational position steering, the EPID method agreed with IC Profiler method to within 0.03 ± 0.05 mm (1 SD) at isocenter. The EPID‐based methods presented are quick to perform, simple, accurate and could easily be integrated with the linac, potentially via the MPC application. The methods have the potential to remove user variability and to standardize the process of beam steering throughout the radiotherapy community.
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Affiliation(s)
- Michael P Barnes
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, NSW, Australia.,School of Medical Radiation Sciences, University of Newcastle, Newcastle, NSW, Australia.,School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW, Australia
| | - Frederick W Menk
- School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW, Australia
| | - Bishnu P Lamichhane
- School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW, Australia
| | - Peter B Greer
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, NSW, Australia.,School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW, Australia
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16
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Harry T, Yaddanapudi S, Cai B, Stinson K, Murty Goddu S, Noel C, Mutic S, Pawlicki T. Risk assessment of a new acceptance testing procedure for conventional linear accelerators. Med Phys 2017; 44:5610-5616. [DOI: 10.1002/mp.12527] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/09/2017] [Accepted: 08/15/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Taylor Harry
- Department of Radiation Medicine and Applied Sciences; University of California San Diego; 3855 Health Sciences Dr La Jolla CA 92093 USA
| | - Sridhar Yaddanapudi
- Department of Radiation Oncology; Washington University School of Medicine; 4921 Parkview Pl St. Louis MO 63110 USA
| | - Bin Cai
- Department of Radiation Oncology; Washington University School of Medicine; 4921 Parkview Pl St. Louis MO 63110 USA
| | - Keith Stinson
- Varian Medical Systems; 3100 Hansen Way Palo Alto CA 94304 USA
| | - S. Murty Goddu
- Department of Radiation Oncology; Washington University School of Medicine; 4921 Parkview Pl St. Louis MO 63110 USA
| | - Camille Noel
- Department of Radiation Oncology; Washington University School of Medicine; 4921 Parkview Pl St. Louis MO 63110 USA
| | - Sasa Mutic
- Department of Radiation Oncology; Washington University School of Medicine; 4921 Parkview Pl St. Louis MO 63110 USA
| | - Todd Pawlicki
- Department of Radiation Medicine and Applied Sciences; University of California San Diego; 3855 Health Sciences Dr La Jolla CA 92093 USA
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