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VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests

In VMAT treatment delivery the ability of the linear accelerator (linac) to accurately control dose versus gantry angle is critical to delivering the plan correctly. A new VMAT test delivery was developed to specifically test the dose versus gantry angle with the full range of allowed gantry speeds...

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Autores principales: Barnes, Michael P., Rowshanfarzad, Pejman, Greer, Peter B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5690937/
https://www.ncbi.nlm.nih.gov/pubmed/27167282
http://dx.doi.org/10.1120/jacmp.v17i3.6067
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author Barnes, Michael P.
Rowshanfarzad, Pejman
Greer, Peter B.
author_facet Barnes, Michael P.
Rowshanfarzad, Pejman
Greer, Peter B.
author_sort Barnes, Michael P.
collection PubMed
description In VMAT treatment delivery the ability of the linear accelerator (linac) to accurately control dose versus gantry angle is critical to delivering the plan correctly. A new VMAT test delivery was developed to specifically test the dose versus gantry angle with the full range of allowed gantry speeds and dose rates. The gantry‐mounted IBA MatriXX with attached inclinometer was used in movie mode to measure the instantaneous relative dose versus gantry angle during the plan every 0.54 s. The results were compared to the expected relative dose at each gantry angle calculated from the plan. The same dataset was also used to compare the instantaneous gantry speeds throughout the delivery compared to the expected gantry speeds from the plan. Measurements performed across four linacs generally show agreement between measurement and plan to within 1.5% in the constant dose rate regions and dose rate modulation within 0.1 s of the plan. Instantaneous gantry speed was measured to be within [Formula: see text] of the plan (1 SD). An error in one linac was detected in that the nominal gantry speed was incorrectly calibrated. This test provides a practical method to quality‐assure critical aspects of VMAT delivery including dose versus gantry angle and gantry speed control. The method can be performed with any detector that can acquire time‐resolved dosimetric information that can be synchronized with a measurement of gantry angle. The test fulfils several of the aims of the recent Netherlands Commission on Radiation Dosimetry (NCS) Report 24, which provides recommendations for comprehensive VMAT quality assurance. PACS number(s): 87.55.Qr
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spelling pubmed-56909372018-04-02 VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests Barnes, Michael P. Rowshanfarzad, Pejman Greer, Peter B. J Appl Clin Med Phys Radiation Oncology Physics In VMAT treatment delivery the ability of the linear accelerator (linac) to accurately control dose versus gantry angle is critical to delivering the plan correctly. A new VMAT test delivery was developed to specifically test the dose versus gantry angle with the full range of allowed gantry speeds and dose rates. The gantry‐mounted IBA MatriXX with attached inclinometer was used in movie mode to measure the instantaneous relative dose versus gantry angle during the plan every 0.54 s. The results were compared to the expected relative dose at each gantry angle calculated from the plan. The same dataset was also used to compare the instantaneous gantry speeds throughout the delivery compared to the expected gantry speeds from the plan. Measurements performed across four linacs generally show agreement between measurement and plan to within 1.5% in the constant dose rate regions and dose rate modulation within 0.1 s of the plan. Instantaneous gantry speed was measured to be within [Formula: see text] of the plan (1 SD). An error in one linac was detected in that the nominal gantry speed was incorrectly calibrated. This test provides a practical method to quality‐assure critical aspects of VMAT delivery including dose versus gantry angle and gantry speed control. The method can be performed with any detector that can acquire time‐resolved dosimetric information that can be synchronized with a measurement of gantry angle. The test fulfils several of the aims of the recent Netherlands Commission on Radiation Dosimetry (NCS) Report 24, which provides recommendations for comprehensive VMAT quality assurance. PACS number(s): 87.55.Qr John Wiley and Sons Inc. 2016-05-08 /pmc/articles/PMC5690937/ /pubmed/27167282 http://dx.doi.org/10.1120/jacmp.v17i3.6067 Text en © 2016 The Authors. This is an open access article under the terms of the Creative Commons Attribution (http://creativecommons.org/licenses/by/3.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Oncology Physics
Barnes, Michael P.
Rowshanfarzad, Pejman
Greer, Peter B.
VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests
title VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests
title_full VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests
title_fullStr VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests
title_full_unstemmed VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests
title_short VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests
title_sort vmat linear accelerator commissioning and quality assurance: dose control and gantry speed tests
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5690937/
https://www.ncbi.nlm.nih.gov/pubmed/27167282
http://dx.doi.org/10.1120/jacmp.v17i3.6067
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