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Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials

In the recommendations of Task Group #43 from American Association of Physicists in Medicine (AAPM TG43), methods of brachytherapy source dosimetry are recommended, under full scattering conditions. However, in actual brachytherapy procedures, sources may not be surrounded by full scattering tissue...

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Autores principales: Zehtabian, Mehdi, Sina, Sedigheh, Faghihi, Reza, Meigooni, Ali
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714407/
https://www.ncbi.nlm.nih.gov/pubmed/23652255
http://dx.doi.org/10.1120/jacmp.v14i3.4228
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author Zehtabian, Mehdi
Sina, Sedigheh
Faghihi, Reza
Meigooni, Ali
author_facet Zehtabian, Mehdi
Sina, Sedigheh
Faghihi, Reza
Meigooni, Ali
author_sort Zehtabian, Mehdi
collection PubMed
description In the recommendations of Task Group #43 from American Association of Physicists in Medicine (AAPM TG43), methods of brachytherapy source dosimetry are recommended, under full scattering conditions. However, in actual brachytherapy procedures, sources may not be surrounded by full scattering tissue in all directions. Clinical examples include high‐dose‐rate (HDR) brachytherapy of the breast or low‐dose‐rate (LDR) brachytherapy of ocular melanoma using eye plaque treatment with [Formula: see text] and [Formula: see text]. In this work, the impact of the missing tissue on the TG‐43–recommended dosimetric parameters of different brachytherapy sources was investigated. The impact of missing tissue on the TG‐43–recommended dosimetric parameters of [Formula: see text] , and [Formula: see text] brachytherapy sources was investigated using the MCNP5 Monte Carlo code. These evaluations were performed by placing the sources at different locations inside a [Formula: see text] cubical water phantom and comparing the results with the values of the source located at the center of the phantom, which is in a full scattering condition. The differences between the thickness of the overlying tissues for different source positions and the thickness of the overlying tissue in full scattering condition is referred to as missing tissue. The results of these investigations indicate that values of the radial dose function and 2D anisotropy function vary as a function of the thickness of missing tissue, only in the direction of the missing tissue. These changes for radial dose function were up to 5%, 11%, and 8% for [Formula: see text] , and [Formula: see text] , respectively. No significant changes are observed for the values of the dose rate constants. In this project, we have demonstrated that the TG‐43 dosimetric parameters may only change in the directions of the missing tissue. These results are more practical than the published data by different investigators in which a symmetric effect of the missing tissue on the dosimetric parameters of brachytherapy source are being considered, regardless of the implant geometry in real clinical cases. PACS number: 87.53.JW
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spelling pubmed-57144072018-04-02 Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials Zehtabian, Mehdi Sina, Sedigheh Faghihi, Reza Meigooni, Ali J Appl Clin Med Phys Radiation Oncology Physics In the recommendations of Task Group #43 from American Association of Physicists in Medicine (AAPM TG43), methods of brachytherapy source dosimetry are recommended, under full scattering conditions. However, in actual brachytherapy procedures, sources may not be surrounded by full scattering tissue in all directions. Clinical examples include high‐dose‐rate (HDR) brachytherapy of the breast or low‐dose‐rate (LDR) brachytherapy of ocular melanoma using eye plaque treatment with [Formula: see text] and [Formula: see text]. In this work, the impact of the missing tissue on the TG‐43–recommended dosimetric parameters of different brachytherapy sources was investigated. The impact of missing tissue on the TG‐43–recommended dosimetric parameters of [Formula: see text] , and [Formula: see text] brachytherapy sources was investigated using the MCNP5 Monte Carlo code. These evaluations were performed by placing the sources at different locations inside a [Formula: see text] cubical water phantom and comparing the results with the values of the source located at the center of the phantom, which is in a full scattering condition. The differences between the thickness of the overlying tissues for different source positions and the thickness of the overlying tissue in full scattering condition is referred to as missing tissue. The results of these investigations indicate that values of the radial dose function and 2D anisotropy function vary as a function of the thickness of missing tissue, only in the direction of the missing tissue. These changes for radial dose function were up to 5%, 11%, and 8% for [Formula: see text] , and [Formula: see text] , respectively. No significant changes are observed for the values of the dose rate constants. In this project, we have demonstrated that the TG‐43 dosimetric parameters may only change in the directions of the missing tissue. These results are more practical than the published data by different investigators in which a symmetric effect of the missing tissue on the dosimetric parameters of brachytherapy source are being considered, regardless of the implant geometry in real clinical cases. PACS number: 87.53.JW John Wiley and Sons Inc. 2013-05-06 /pmc/articles/PMC5714407/ /pubmed/23652255 http://dx.doi.org/10.1120/jacmp.v14i3.4228 Text en © 2013 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
Zehtabian, Mehdi
Sina, Sedigheh
Faghihi, Reza
Meigooni, Ali
Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials
title Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials
title_full Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials
title_fullStr Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials
title_full_unstemmed Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials
title_short Perturbation of TG‐43 parameters of the brachytherapy sources under insufficient scattering materials
title_sort perturbation of tg‐43 parameters of the brachytherapy sources under insufficient scattering materials
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714407/
https://www.ncbi.nlm.nih.gov/pubmed/23652255
http://dx.doi.org/10.1120/jacmp.v14i3.4228
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