Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans

Body contour changes are commonly seen in prostate and head and neck (H&N) patients undergoing volumetric modulated arc therapy (VMAT) treatments, which may cause a discrepancy between the planned dose and the delivered dose. Dosimetrists, radiation oncologists or medical physicists sometimes ar...

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Autores principales: Sun, Lingyue, Kirkby, Charles, Smith, Wendy
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6448168/
https://www.ncbi.nlm.nih.gov/pubmed/30927323
http://dx.doi.org/10.1002/acm2.12571
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author Sun, Lingyue
Kirkby, Charles
Smith, Wendy
author_facet Sun, Lingyue
Kirkby, Charles
Smith, Wendy
author_sort Sun, Lingyue
collection PubMed
description Body contour changes are commonly seen in prostate and head and neck (H&N) patients undergoing volumetric modulated arc therapy (VMAT) treatments, which may cause a discrepancy between the planned dose and the delivered dose. Dosimetrists, radiation oncologists or medical physicists sometimes are required to visually assess the dosimetric impact of body contour changes and make a judgment call on whether further re‐assessment of the plan is needed. However, an intuitive judgment cannot always be made in a timely manner due to the complexity of VMAT plans as well as the complicated forms of body contour changes. This study evaluated the dosimetric effect of body contour changes for prostate and H&N patients to help with clinical decision‐making. By analyzing the one‐dimensional spatial dose profiles from the original body and the body with different body contour deformations, rules of thumb for dose percentage change and isodose line shift due to body contour changes were ascertained. Moreover, based on dose distribution comparison using three‐dimensional gamma analysis, the response of the clinical prostate and H&N VMAT plans to body contour changes was assessed. Within center specific dose deviation tolerances, prostate patients who had less than 2 cm single side body contour change or less than 1 cm uniform body contour change were unlikely to need plan re‐assessment; H&N VMAT plans with less than 1 cm uniform body contour change or less than 1 cm shoulder superior–inferior positional change were also unlikely to trigger further evaluation. Dose percentage change and isodose line shift were considered independently from the problem of volume changes in this study, but clinically, both aspects must be considered.
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spelling pubmed-64481682019-04-15 Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans Sun, Lingyue Kirkby, Charles Smith, Wendy J Appl Clin Med Phys Radiation Oncology Physics Body contour changes are commonly seen in prostate and head and neck (H&N) patients undergoing volumetric modulated arc therapy (VMAT) treatments, which may cause a discrepancy between the planned dose and the delivered dose. Dosimetrists, radiation oncologists or medical physicists sometimes are required to visually assess the dosimetric impact of body contour changes and make a judgment call on whether further re‐assessment of the plan is needed. However, an intuitive judgment cannot always be made in a timely manner due to the complexity of VMAT plans as well as the complicated forms of body contour changes. This study evaluated the dosimetric effect of body contour changes for prostate and H&N patients to help with clinical decision‐making. By analyzing the one‐dimensional spatial dose profiles from the original body and the body with different body contour deformations, rules of thumb for dose percentage change and isodose line shift due to body contour changes were ascertained. Moreover, based on dose distribution comparison using three‐dimensional gamma analysis, the response of the clinical prostate and H&N VMAT plans to body contour changes was assessed. Within center specific dose deviation tolerances, prostate patients who had less than 2 cm single side body contour change or less than 1 cm uniform body contour change were unlikely to need plan re‐assessment; H&N VMAT plans with less than 1 cm uniform body contour change or less than 1 cm shoulder superior–inferior positional change were also unlikely to trigger further evaluation. Dose percentage change and isodose line shift were considered independently from the problem of volume changes in this study, but clinically, both aspects must be considered. John Wiley and Sons Inc. 2019-03-29 /pmc/articles/PMC6448168/ /pubmed/30927323 http://dx.doi.org/10.1002/acm2.12571 Text en © 2019 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Oncology Physics
Sun, Lingyue
Kirkby, Charles
Smith, Wendy
Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans
title Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans
title_full Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans
title_fullStr Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans
title_full_unstemmed Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans
title_short Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans
title_sort dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6448168/
https://www.ncbi.nlm.nih.gov/pubmed/30927323
http://dx.doi.org/10.1002/acm2.12571
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