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A simple calculation method for determination of equivalent square field
Determination of the equivalent square fields for rectangular and shielded fields is of great importance in radiotherapy centers and treatment planning software. This is accomplished using standard tables and empirical formulas. The goal of this paper is to present a formula based on analysis of sca...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Medknow Publications & Media Pvt Ltd
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3339142/ https://www.ncbi.nlm.nih.gov/pubmed/22557801 http://dx.doi.org/10.4103/0971-6203.94746 |
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author | Shafiei, Seyed Ali Hasanzadeh, Hadi Shafiei, Seyed Ahmad |
author_facet | Shafiei, Seyed Ali Hasanzadeh, Hadi Shafiei, Seyed Ahmad |
author_sort | Shafiei, Seyed Ali |
collection | PubMed |
description | Determination of the equivalent square fields for rectangular and shielded fields is of great importance in radiotherapy centers and treatment planning software. This is accomplished using standard tables and empirical formulas. The goal of this paper is to present a formula based on analysis of scatter reduction due to inverse square law to obtain equivalent field. Tables are published by different agencies such as ICRU (International Commission on Radiation Units and measurements), which are based on experimental data; but there exist mathematical formulas that yield the equivalent square field of an irregular rectangular field which are used extensively in computation techniques for dose determination. These processes lead to some complicated and time-consuming formulas for which the current study was designed. In this work, considering the portion of scattered radiation in absorbed dose at a point of measurement, a numerical formula was obtained based on which a simple formula was developed to calculate equivalent square field. Using polar coordinate and inverse square law will lead to a simple formula for calculation of equivalent field. The presented method is an analytical approach based on which one can estimate the equivalent square field of a rectangular field and may be used for a shielded field or an off-axis point. Besides, one can calculate equivalent field of rectangular field with the concept of decreased scatter radiation with inverse square law with a good approximation. This method may be useful in computing Percentage Depth Dose and Tissue-Phantom Ratio which are extensively used in treatment planning. |
format | Online Article Text |
id | pubmed-3339142 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Medknow Publications & Media Pvt Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-33391422012-05-03 A simple calculation method for determination of equivalent square field Shafiei, Seyed Ali Hasanzadeh, Hadi Shafiei, Seyed Ahmad J Med Phys Technical Note Determination of the equivalent square fields for rectangular and shielded fields is of great importance in radiotherapy centers and treatment planning software. This is accomplished using standard tables and empirical formulas. The goal of this paper is to present a formula based on analysis of scatter reduction due to inverse square law to obtain equivalent field. Tables are published by different agencies such as ICRU (International Commission on Radiation Units and measurements), which are based on experimental data; but there exist mathematical formulas that yield the equivalent square field of an irregular rectangular field which are used extensively in computation techniques for dose determination. These processes lead to some complicated and time-consuming formulas for which the current study was designed. In this work, considering the portion of scattered radiation in absorbed dose at a point of measurement, a numerical formula was obtained based on which a simple formula was developed to calculate equivalent square field. Using polar coordinate and inverse square law will lead to a simple formula for calculation of equivalent field. The presented method is an analytical approach based on which one can estimate the equivalent square field of a rectangular field and may be used for a shielded field or an off-axis point. Besides, one can calculate equivalent field of rectangular field with the concept of decreased scatter radiation with inverse square law with a good approximation. This method may be useful in computing Percentage Depth Dose and Tissue-Phantom Ratio which are extensively used in treatment planning. Medknow Publications & Media Pvt Ltd 2012 /pmc/articles/PMC3339142/ /pubmed/22557801 http://dx.doi.org/10.4103/0971-6203.94746 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 Shafiei, Seyed Ali Hasanzadeh, Hadi Shafiei, Seyed Ahmad A simple calculation method for determination of equivalent square field |
title | A simple calculation method for determination of equivalent square field |
title_full | A simple calculation method for determination of equivalent square field |
title_fullStr | A simple calculation method for determination of equivalent square field |
title_full_unstemmed | A simple calculation method for determination of equivalent square field |
title_short | A simple calculation method for determination of equivalent square field |
title_sort | simple calculation method for determination of equivalent square field |
topic | Technical Note |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3339142/ https://www.ncbi.nlm.nih.gov/pubmed/22557801 http://dx.doi.org/10.4103/0971-6203.94746 |
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