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Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy
In vivo dosimetry was carried out for 152 patients receiving external beam radiotherapy and the treatment sites were divided into two main groups: Thorax, Abdomen, and Pelvic (120 fields) and Head and Neck (52 fields). Combined entrance and exit dose measurements were performed using LiF: Mg, Cu, P...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Medknow Publications & Media Pvt Ltd
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3607346/ https://www.ncbi.nlm.nih.gov/pubmed/23532059 http://dx.doi.org/10.4103/0971-6203.106605 |
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author | Moghaddam, Behnaz Ghanbar Vahabi-Moghaddam, Masoud Sadremomtaz, Alireza |
author_facet | Moghaddam, Behnaz Ghanbar Vahabi-Moghaddam, Masoud Sadremomtaz, Alireza |
author_sort | Moghaddam, Behnaz Ghanbar |
collection | PubMed |
description | In vivo dosimetry was carried out for 152 patients receiving external beam radiotherapy and the treatment sites were divided into two main groups: Thorax, Abdomen, and Pelvic (120 fields) and Head and Neck (52 fields). Combined entrance and exit dose measurements were performed using LiF: Mg, Cu, P thermoluminescent dosimeters (TLDs). Water-equivalent (effective) thicknesses and target dose were evaluated using dose transmission data. The ratio of measured to expected value for each quantity was considered as an indicator for the accuracy of the parameter. The average ratio of the entrance dose was evaluated as 1.01 ± 0.07. In the diameter measurement, the mean ratio of effective depth divided by the contour depth is 1.00 ± 0.13 that shows a wide distribution which reflects the influence of contour inaccuracies as well as tissue inhomogeneities. At the target level, the mean ratio of measured to the prescribed dose is 1.00 ± 0.07. According to our findings, the difference between effective depth and patient depth has a direct relation to target dose discrepancies. There are some inevitable sources which may cause the difference. Evaluation and application of effective diameter in treatment calculations would lead to a more reliable target dose, especially for fields which involve Thorax, Abdomen, and Pelvic. |
format | Online Article Text |
id | pubmed-3607346 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Medknow Publications & Media Pvt Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-36073462013-03-26 Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy Moghaddam, Behnaz Ghanbar Vahabi-Moghaddam, Masoud Sadremomtaz, Alireza J Med Phys Technical Note In vivo dosimetry was carried out for 152 patients receiving external beam radiotherapy and the treatment sites were divided into two main groups: Thorax, Abdomen, and Pelvic (120 fields) and Head and Neck (52 fields). Combined entrance and exit dose measurements were performed using LiF: Mg, Cu, P thermoluminescent dosimeters (TLDs). Water-equivalent (effective) thicknesses and target dose were evaluated using dose transmission data. The ratio of measured to expected value for each quantity was considered as an indicator for the accuracy of the parameter. The average ratio of the entrance dose was evaluated as 1.01 ± 0.07. In the diameter measurement, the mean ratio of effective depth divided by the contour depth is 1.00 ± 0.13 that shows a wide distribution which reflects the influence of contour inaccuracies as well as tissue inhomogeneities. At the target level, the mean ratio of measured to the prescribed dose is 1.00 ± 0.07. According to our findings, the difference between effective depth and patient depth has a direct relation to target dose discrepancies. There are some inevitable sources which may cause the difference. Evaluation and application of effective diameter in treatment calculations would lead to a more reliable target dose, especially for fields which involve Thorax, Abdomen, and Pelvic. Medknow Publications & Media Pvt Ltd 2013 /pmc/articles/PMC3607346/ /pubmed/23532059 http://dx.doi.org/10.4103/0971-6203.106605 Text en Copyright: © Journal of Medical Physics http://creativecommons.org/licenses/by-nc-sa/3.0 This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Technical Note Moghaddam, Behnaz Ghanbar Vahabi-Moghaddam, Masoud Sadremomtaz, Alireza Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy |
title | Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy |
title_full | Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy |
title_fullStr | Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy |
title_full_unstemmed | Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy |
title_short | Evaluation of target dose based on water-equivalent thickness in external beam radiotherapy |
title_sort | evaluation of target dose based on water-equivalent thickness in external beam radiotherapy |
topic | Technical Note |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3607346/ https://www.ncbi.nlm.nih.gov/pubmed/23532059 http://dx.doi.org/10.4103/0971-6203.106605 |
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