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Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam
The purpose of the study was to investigate the use of the equivalent square formula for determining the surface dose from a rectangular photon beam. A 6 MV therapeutic photon beam delivered from a Varian Clinac 23EX medical linear accelerator was modeled using the EGS4nrc Monte Carlo simulation pac...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714569/ https://www.ncbi.nlm.nih.gov/pubmed/24036872 http://dx.doi.org/10.1120/jacmp.v14i5.4340 |
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author | Apipunyasopon, Lukkana Srisatit, Somyot Phaisangittisakul, Nakorn |
author_facet | Apipunyasopon, Lukkana Srisatit, Somyot Phaisangittisakul, Nakorn |
author_sort | Apipunyasopon, Lukkana |
collection | PubMed |
description | The purpose of the study was to investigate the use of the equivalent square formula for determining the surface dose from a rectangular photon beam. A 6 MV therapeutic photon beam delivered from a Varian Clinac 23EX medical linear accelerator was modeled using the EGS4nrc Monte Carlo simulation package. It was then used to calculate the dose in the build‐up region from both square and rectangular fields. The field patterns were defined by various settings of the X‐ and Y‐collimator jaw ranging from 5 to 20 cm. Dose measurements were performed using a thermoluminescence dosimeter and a Markus parallel‐plate ionization chamber on the four square fields ([Formula: see text] , and [Formula: see text]). The surface dose was acquired by extrapolating the build‐up doses to the surface. An equivalent square for a rectangular field was determined using the area‐to‐perimeter formula, and the surface dose of the equivalent square was estimated using the square‐field data. The surface dose of square field increased linearly from approximately 10% to 28% as the side of the square field increased from 5 to 20 cm. The influence of collimator exchange on the surface dose was found to be not significant. The difference in the percentage surface dose of the rectangular field compared to that of the relevant equivalent square was insignificant and can be clinically neglected. The use of the area‐to‐perimeter formula for an equivalent square field can provide a clinically acceptable surface dose estimation for a rectangular field from a 6 MV therapy photon beam. PACS number: 87.55.ne |
format | Online Article Text |
id | pubmed-5714569 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-57145692018-04-02 Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam Apipunyasopon, Lukkana Srisatit, Somyot Phaisangittisakul, Nakorn J Appl Clin Med Phys Radiation Oncology Physics The purpose of the study was to investigate the use of the equivalent square formula for determining the surface dose from a rectangular photon beam. A 6 MV therapeutic photon beam delivered from a Varian Clinac 23EX medical linear accelerator was modeled using the EGS4nrc Monte Carlo simulation package. It was then used to calculate the dose in the build‐up region from both square and rectangular fields. The field patterns were defined by various settings of the X‐ and Y‐collimator jaw ranging from 5 to 20 cm. Dose measurements were performed using a thermoluminescence dosimeter and a Markus parallel‐plate ionization chamber on the four square fields ([Formula: see text] , and [Formula: see text]). The surface dose was acquired by extrapolating the build‐up doses to the surface. An equivalent square for a rectangular field was determined using the area‐to‐perimeter formula, and the surface dose of the equivalent square was estimated using the square‐field data. The surface dose of square field increased linearly from approximately 10% to 28% as the side of the square field increased from 5 to 20 cm. The influence of collimator exchange on the surface dose was found to be not significant. The difference in the percentage surface dose of the rectangular field compared to that of the relevant equivalent square was insignificant and can be clinically neglected. The use of the area‐to‐perimeter formula for an equivalent square field can provide a clinically acceptable surface dose estimation for a rectangular field from a 6 MV therapy photon beam. PACS number: 87.55.ne John Wiley and Sons Inc. 2013-09-06 /pmc/articles/PMC5714569/ /pubmed/24036872 http://dx.doi.org/10.1120/jacmp.v14i5.4340 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 Apipunyasopon, Lukkana Srisatit, Somyot Phaisangittisakul, Nakorn Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam |
title | Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam |
title_full | Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam |
title_fullStr | Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam |
title_full_unstemmed | Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam |
title_short | Equivalent square formula for determining the surface dose of rectangular field from 6 MV therapeutic photon beam |
title_sort | equivalent square formula for determining the surface dose of rectangular field from 6 mv therapeutic photon beam |
topic | Radiation Oncology Physics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714569/ https://www.ncbi.nlm.nih.gov/pubmed/24036872 http://dx.doi.org/10.1120/jacmp.v14i5.4340 |
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