Cargando…
Determination of field size‐dependent wedge factors from a few selected measurements
Some modern treatment‐planning systems (TPSs) provide for input of wedge factor (WF) tables covering the entire range of square and elongated fields available on the LINAC. Depending on the field size increment chosen and the number of available wedge orientations, one may have to take more than 100...
Autores principales: | , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2005
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723504/ https://www.ncbi.nlm.nih.gov/pubmed/15770196 http://dx.doi.org/10.1120/jacmp.v6i1.2063 |
_version_ | 1783285227165057024 |
---|---|
author | Popple, Richard A. Brezovich, Ivan A. Duan, Jun Shen, Sui Pareek, Prem N. Ye, Sung‐Joon |
author_facet | Popple, Richard A. Brezovich, Ivan A. Duan, Jun Shen, Sui Pareek, Prem N. Ye, Sung‐Joon |
author_sort | Popple, Richard A. |
collection | PubMed |
description | Some modern treatment‐planning systems (TPSs) provide for input of wedge factor (WF) tables covering the entire range of square and elongated fields available on the LINAC. Depending on the field size increment chosen and the number of available wedge orientations, one may have to take more than 100 measurements per wedge and photon energy to commission the TPS. To expedite TPS commissioning while maintaining high accuracy, we demonstrate a simple method that requires only a few measurements per wedge, from which the remaining wedge factors can be found through linear interpolation based on field area. For the externally mounted wedges of two common LINACs, we have shown that WFs are proportional to field area and are nearly independent of field elongation and wedge orientation. Wedge factors computed from five to seven measurements comprised of square fields and a single, large rectangular field agreed with direct measurements throughout the entire range of achievable field dimensions within 0.6% at 6 MV and within 1% at 15 MV. Making the same set of measurements and using the equivalent square method to find WFs at other field sizes leads to errors up to 2%. Measuring the WF for a [Formula: see text] field and applying the same value to all field sizes can lead to errors of up to 10% at both 6 MV and 15 MV. PACS numbers: 87.53.Bn, 87.53.Mr |
format | Online Article Text |
id | pubmed-5723504 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2005 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-57235042018-04-02 Determination of field size‐dependent wedge factors from a few selected measurements Popple, Richard A. Brezovich, Ivan A. Duan, Jun Shen, Sui Pareek, Prem N. Ye, Sung‐Joon J Appl Clin Med Phys Radiation Oncology Physics Some modern treatment‐planning systems (TPSs) provide for input of wedge factor (WF) tables covering the entire range of square and elongated fields available on the LINAC. Depending on the field size increment chosen and the number of available wedge orientations, one may have to take more than 100 measurements per wedge and photon energy to commission the TPS. To expedite TPS commissioning while maintaining high accuracy, we demonstrate a simple method that requires only a few measurements per wedge, from which the remaining wedge factors can be found through linear interpolation based on field area. For the externally mounted wedges of two common LINACs, we have shown that WFs are proportional to field area and are nearly independent of field elongation and wedge orientation. Wedge factors computed from five to seven measurements comprised of square fields and a single, large rectangular field agreed with direct measurements throughout the entire range of achievable field dimensions within 0.6% at 6 MV and within 1% at 15 MV. Making the same set of measurements and using the equivalent square method to find WFs at other field sizes leads to errors up to 2%. Measuring the WF for a [Formula: see text] field and applying the same value to all field sizes can lead to errors of up to 10% at both 6 MV and 15 MV. PACS numbers: 87.53.Bn, 87.53.Mr John Wiley and Sons Inc. 2005-03-17 /pmc/articles/PMC5723504/ /pubmed/15770196 http://dx.doi.org/10.1120/jacmp.v6i1.2063 Text en © 2005 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 Popple, Richard A. Brezovich, Ivan A. Duan, Jun Shen, Sui Pareek, Prem N. Ye, Sung‐Joon Determination of field size‐dependent wedge factors from a few selected measurements |
title | Determination of field size‐dependent wedge factors from a few selected measurements |
title_full | Determination of field size‐dependent wedge factors from a few selected measurements |
title_fullStr | Determination of field size‐dependent wedge factors from a few selected measurements |
title_full_unstemmed | Determination of field size‐dependent wedge factors from a few selected measurements |
title_short | Determination of field size‐dependent wedge factors from a few selected measurements |
title_sort | determination of field size‐dependent wedge factors from a few selected measurements |
topic | Radiation Oncology Physics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723504/ https://www.ncbi.nlm.nih.gov/pubmed/15770196 http://dx.doi.org/10.1120/jacmp.v6i1.2063 |
work_keys_str_mv | AT popplericharda determinationoffieldsizedependentwedgefactorsfromafewselectedmeasurements AT brezovichivana determinationoffieldsizedependentwedgefactorsfromafewselectedmeasurements AT duanjun determinationoffieldsizedependentwedgefactorsfromafewselectedmeasurements AT shensui determinationoffieldsizedependentwedgefactorsfromafewselectedmeasurements AT pareekpremn determinationoffieldsizedependentwedgefactorsfromafewselectedmeasurements AT yesungjoon determinationoffieldsizedependentwedgefactorsfromafewselectedmeasurements |