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Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung

The aim of this study is to provide guidelines for the selection of external‐beam radiation therapy target margins to compensate for target motion in the lung during treatment planning. A convolution model was employed to predict the effect of target motion on the delivered dose distribution. The ac...

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Detalles Bibliográficos
Autores principales: Foster, W Kyle, Osei, Ernest, Barnett, Rob
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5689985/
https://www.ncbi.nlm.nih.gov/pubmed/25679166
http://dx.doi.org/10.1120/jacmp.v16i1.5089
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author Foster, W Kyle
Osei, Ernest
Barnett, Rob
author_facet Foster, W Kyle
Osei, Ernest
Barnett, Rob
author_sort Foster, W Kyle
collection PubMed
description The aim of this study is to provide guidelines for the selection of external‐beam radiation therapy target margins to compensate for target motion in the lung during treatment planning. A convolution model was employed to predict the effect of target motion on the delivered dose distribution. The accuracy of the model was confirmed with radiochromic film measurements in both static and dynamic phantom modes. 502 unique patient breathing traces were recorded and used to simulate the effect of target motion on a dose distribution. A 1D probability density function (PDF) representing the position of the target throughout the breathing cycle was generated from each breathing trace obtained during 4D CT. Changes in the target [Formula: see text] (the minimum dose received by 95% of the treatment target) due to target motion were analyzed and shown to correlate with the standard deviation of the PDF. Furthermore, the amount of target [Formula: see text] recovered per millimeter of increased field width was also shown to correlate with the standard deviation of the PDF. The sensitivity of changes in dose coverage with respect to target size was also determined. Margin selection recommendations that can be used to compensate for loss of target [Formula: see text] were generated based on the simulation results. These results are discussed in the context of clinical plans. We conclude that, for PDF standard deviations less than 0.4 cm with target sizes greater than 5 cm, little or no additional margins are required. Targets which are smaller than 5 cm with PDF standard deviations larger than 0.4 cm are most susceptible to loss of coverage. The largest additional required margin in this study was determined to be 8 mm. PACS numbers: 87.53.Bn, 87.53.Kn, 87.55.D‐, 87.55.Gh
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spelling pubmed-56899852018-04-02 Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung Foster, W Kyle Osei, Ernest Barnett, Rob J Appl Clin Med Phys Radiation Oncology Physics The aim of this study is to provide guidelines for the selection of external‐beam radiation therapy target margins to compensate for target motion in the lung during treatment planning. A convolution model was employed to predict the effect of target motion on the delivered dose distribution. The accuracy of the model was confirmed with radiochromic film measurements in both static and dynamic phantom modes. 502 unique patient breathing traces were recorded and used to simulate the effect of target motion on a dose distribution. A 1D probability density function (PDF) representing the position of the target throughout the breathing cycle was generated from each breathing trace obtained during 4D CT. Changes in the target [Formula: see text] (the minimum dose received by 95% of the treatment target) due to target motion were analyzed and shown to correlate with the standard deviation of the PDF. Furthermore, the amount of target [Formula: see text] recovered per millimeter of increased field width was also shown to correlate with the standard deviation of the PDF. The sensitivity of changes in dose coverage with respect to target size was also determined. Margin selection recommendations that can be used to compensate for loss of target [Formula: see text] were generated based on the simulation results. These results are discussed in the context of clinical plans. We conclude that, for PDF standard deviations less than 0.4 cm with target sizes greater than 5 cm, little or no additional margins are required. Targets which are smaller than 5 cm with PDF standard deviations larger than 0.4 cm are most susceptible to loss of coverage. The largest additional required margin in this study was determined to be 8 mm. PACS numbers: 87.53.Bn, 87.53.Kn, 87.55.D‐, 87.55.Gh John Wiley and Sons Inc. 2015-01-08 /pmc/articles/PMC5689985/ /pubmed/25679166 http://dx.doi.org/10.1120/jacmp.v16i1.5089 Text en © 2015 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
Foster, W Kyle
Osei, Ernest
Barnett, Rob
Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung
title Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung
title_full Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung
title_fullStr Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung
title_full_unstemmed Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung
title_short Margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung
title_sort margin selection to compensate for loss of target dose coverage due to target motion during external‐beam radiation therapy of the lung
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5689985/
https://www.ncbi.nlm.nih.gov/pubmed/25679166
http://dx.doi.org/10.1120/jacmp.v16i1.5089
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