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Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array
Portal dosimetry (PD) was performed for 181 fields from 14 IMRT plans of various clinical sites at gantry zero and source‐to‐detector distance (SDD) of 100 cm. PD was realized using aSi1000 electronic portal imaging device (EPID) and portal dose prediction (PDP) algorithm implemented in Eclipse trea...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2010
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5720403/ https://www.ncbi.nlm.nih.gov/pubmed/21081884 http://dx.doi.org/10.1120/jacmp.v11i4.3268 |
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author | Sharma, Dayananda Shamurailatpam Mhatre, Vaibav Heigrujam, Malhotra Talapatra, Kaustav Mallik, Suman |
author_facet | Sharma, Dayananda Shamurailatpam Mhatre, Vaibav Heigrujam, Malhotra Talapatra, Kaustav Mallik, Suman |
author_sort | Sharma, Dayananda Shamurailatpam |
collection | PubMed |
description | Portal dosimetry (PD) was performed for 181 fields from 14 IMRT plans of various clinical sites at gantry zero and source‐to‐detector distance (SDD) of 100 cm. PD was realized using aSi1000 electronic portal imaging device (EPID) and portal dose prediction (PDP) algorithm implemented in Eclipse treatment planning system (TPS). Agreement of PDP predicted and EPID measured photon fluence/dose distribution were evaluated using gamma (γ) index set at 3% at 3 mm distance to point agreement (DTA). Three gamma scaling parameters, maximum [Formula: see text] , average [Formula: see text] and percentage of points with [Formula: see text] were estimated for each field. An independent measurement was carried out using MatriXX 2D ion chamber array with detector plane at 100 cm and [Formula: see text] and [Formula: see text] were estimated using OmniPro IMRT analyzing software. Effect of extended SDD and gantry rotation on portal dosimetry outcome was also investigated for another 45 IMRT fields. PDP predicted and EPID measured photon fluence agrees well with overall mean values of [Formula: see text] and [Formula: see text] 1 at 2.02, 0.24 and 99.43%, respectively. [Formula: see text] value was lower in 15 MV compared to 6 MV IMRT plan. Independent verification using MatriXX showed comparable overall mean values of [Formula: see text] and [Formula: see text] at 0.25 and 99.80%. However, in all plans, MatriXX showed significantly lower [Formula: see text] with an overall mean value of 1.35. In portal dosimetry, compared to gamma values at 100 cm SDD, [Formula: see text] and [Formula: see text] values improve from a mean of 0.16, 0.03 and 0.26 at 110 cm SDD to 0.35, 0.05 and 0.29 at 140 cm SDD. PD outcome was independent of gantry rotation. In conclusion, both MatriXX 2D ion chamber array and portal dosimetry showed comparable results and can be use as an alternative to each other for relative photon fluence verification. PACS number (s): 87.55.D‐, 87.55.de, 87.55.kd,87.55.km,87.55.Qr,87.56Fc: |
format | Online Article Text |
id | pubmed-5720403 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-57204032018-04-02 Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array Sharma, Dayananda Shamurailatpam Mhatre, Vaibav Heigrujam, Malhotra Talapatra, Kaustav Mallik, Suman J Appl Clin Med Phys Radiation Measurements Portal dosimetry (PD) was performed for 181 fields from 14 IMRT plans of various clinical sites at gantry zero and source‐to‐detector distance (SDD) of 100 cm. PD was realized using aSi1000 electronic portal imaging device (EPID) and portal dose prediction (PDP) algorithm implemented in Eclipse treatment planning system (TPS). Agreement of PDP predicted and EPID measured photon fluence/dose distribution were evaluated using gamma (γ) index set at 3% at 3 mm distance to point agreement (DTA). Three gamma scaling parameters, maximum [Formula: see text] , average [Formula: see text] and percentage of points with [Formula: see text] were estimated for each field. An independent measurement was carried out using MatriXX 2D ion chamber array with detector plane at 100 cm and [Formula: see text] and [Formula: see text] were estimated using OmniPro IMRT analyzing software. Effect of extended SDD and gantry rotation on portal dosimetry outcome was also investigated for another 45 IMRT fields. PDP predicted and EPID measured photon fluence agrees well with overall mean values of [Formula: see text] and [Formula: see text] 1 at 2.02, 0.24 and 99.43%, respectively. [Formula: see text] value was lower in 15 MV compared to 6 MV IMRT plan. Independent verification using MatriXX showed comparable overall mean values of [Formula: see text] and [Formula: see text] at 0.25 and 99.80%. However, in all plans, MatriXX showed significantly lower [Formula: see text] with an overall mean value of 1.35. In portal dosimetry, compared to gamma values at 100 cm SDD, [Formula: see text] and [Formula: see text] values improve from a mean of 0.16, 0.03 and 0.26 at 110 cm SDD to 0.35, 0.05 and 0.29 at 140 cm SDD. PD outcome was independent of gantry rotation. In conclusion, both MatriXX 2D ion chamber array and portal dosimetry showed comparable results and can be use as an alternative to each other for relative photon fluence verification. PACS number (s): 87.55.D‐, 87.55.de, 87.55.kd,87.55.km,87.55.Qr,87.56Fc: John Wiley and Sons Inc. 2010-08-19 /pmc/articles/PMC5720403/ /pubmed/21081884 http://dx.doi.org/10.1120/jacmp.v11i4.3268 Text en © 2010 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 Measurements Sharma, Dayananda Shamurailatpam Mhatre, Vaibav Heigrujam, Malhotra Talapatra, Kaustav Mallik, Suman Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array |
title | Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array |
title_full | Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array |
title_fullStr | Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array |
title_full_unstemmed | Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array |
title_short | Portal dosimetry for pretreatment verification of IMRT plan: a comparison with 2D ion chamber array |
title_sort | portal dosimetry for pretreatment verification of imrt plan: a comparison with 2d ion chamber array |
topic | Radiation Measurements |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5720403/ https://www.ncbi.nlm.nih.gov/pubmed/21081884 http://dx.doi.org/10.1120/jacmp.v11i4.3268 |
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