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A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2

The purpose of this study is to determine comparability of three different planar IMRT QA techniques: patient gantry angle composite (PGAC), single gantry angle composite (SGAC), and field by field (FBF), using MapCHECK 2 device and the γ test as performance metrics; and to assess the dependency of...

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Autores principales: Keeling, Vance P., Ahmad, Salahuddin, Jin, Hosang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714623/
https://www.ncbi.nlm.nih.gov/pubmed/24257283
http://dx.doi.org/10.1120/jacmp.v14i6.4398
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author Keeling, Vance P.
Ahmad, Salahuddin
Jin, Hosang
author_facet Keeling, Vance P.
Ahmad, Salahuddin
Jin, Hosang
author_sort Keeling, Vance P.
collection PubMed
description The purpose of this study is to determine comparability of three different planar IMRT QA techniques: patient gantry angle composite (PGAC), single gantry angle composite (SGAC), and field by field (FBF), using MapCHECK 2 device and the γ test as performance metrics; and to assess the dependency of these techniques on intensity modulation, couch attenuation, and detector position (angular dependency). Ten highly modulated head and neck (H&N) and ten moderately modulated prostate IMRT validation plans were delivered using different techniques and were intercompared using the Student's t‐test. The IMRT QA measurements were evaluated by percentage of points passing the γ test for three different criteria: 1% (dose difference)/1 mm (distance to agreement (DTA)) (C1), 2%/2 mm (C2), and 3%/3 mm (C3). To investigate dependency of the IMRT validation on treatment couch, ionization chamber measurements, as well as the conventional MapCHECK 2 QAs, were performed with PGAC and PGAC‐WOC (without couch; using an extended tennis racket‐type insert with negligible attenuation assumed). To determine angular dependency of the MapCHECK 2, patient gantry field‐by‐field (PG‐FBF) technique was delivered and evaluated separately for each field. The differences of γ passing rates between SGAC and FBF were statistically insignificant, while these were statistically significant when compared to PGAC. SGAC and FBF techniques showed statistically insignificant differences between different levels of intensity modulation (H&N vs. Prostate) at C2 and C3 criteria, while PGAC could not for any criteria. The treatment couch has a significant impact on γ passing rates (PGAC vs. PGAC‐WOC), but an ionization chamber‐based IMRT validations showed clinically insignificant dose errors (< 2%) in all cases. This study showed that the MapCHECK 2 device has large angular dependency, especially at gantry angles of 90° and 270°, which dramatically affected the γ passing rates of PGAC. With proper consideration of couch attenuation and beam arrangement, the MapCHECK 2 will produce clinically comparable QA results using the three different planar IMRT QA techniques. PACS numbers: 87.55.km, 87.55.Qr, 87.56.Fc
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spelling pubmed-57146232018-04-02 A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2 Keeling, Vance P. Ahmad, Salahuddin Jin, Hosang J Appl Clin Med Phys Radiation Oncology Physics The purpose of this study is to determine comparability of three different planar IMRT QA techniques: patient gantry angle composite (PGAC), single gantry angle composite (SGAC), and field by field (FBF), using MapCHECK 2 device and the γ test as performance metrics; and to assess the dependency of these techniques on intensity modulation, couch attenuation, and detector position (angular dependency). Ten highly modulated head and neck (H&N) and ten moderately modulated prostate IMRT validation plans were delivered using different techniques and were intercompared using the Student's t‐test. The IMRT QA measurements were evaluated by percentage of points passing the γ test for three different criteria: 1% (dose difference)/1 mm (distance to agreement (DTA)) (C1), 2%/2 mm (C2), and 3%/3 mm (C3). To investigate dependency of the IMRT validation on treatment couch, ionization chamber measurements, as well as the conventional MapCHECK 2 QAs, were performed with PGAC and PGAC‐WOC (without couch; using an extended tennis racket‐type insert with negligible attenuation assumed). To determine angular dependency of the MapCHECK 2, patient gantry field‐by‐field (PG‐FBF) technique was delivered and evaluated separately for each field. The differences of γ passing rates between SGAC and FBF were statistically insignificant, while these were statistically significant when compared to PGAC. SGAC and FBF techniques showed statistically insignificant differences between different levels of intensity modulation (H&N vs. Prostate) at C2 and C3 criteria, while PGAC could not for any criteria. The treatment couch has a significant impact on γ passing rates (PGAC vs. PGAC‐WOC), but an ionization chamber‐based IMRT validations showed clinically insignificant dose errors (< 2%) in all cases. This study showed that the MapCHECK 2 device has large angular dependency, especially at gantry angles of 90° and 270°, which dramatically affected the γ passing rates of PGAC. With proper consideration of couch attenuation and beam arrangement, the MapCHECK 2 will produce clinically comparable QA results using the three different planar IMRT QA techniques. PACS numbers: 87.55.km, 87.55.Qr, 87.56.Fc John Wiley and Sons Inc. 2013-11-04 /pmc/articles/PMC5714623/ /pubmed/24257283 http://dx.doi.org/10.1120/jacmp.v14i6.4398 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
Keeling, Vance P.
Ahmad, Salahuddin
Jin, Hosang
A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2
title A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2
title_full A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2
title_fullStr A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2
title_full_unstemmed A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2
title_short A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2
title_sort comprehensive comparison study of three different planar imrt qa techniques using mapcheck 2
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5714623/
https://www.ncbi.nlm.nih.gov/pubmed/24257283
http://dx.doi.org/10.1120/jacmp.v14i6.4398
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