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Dynamic simulation of motion effects in IMAT lung SBRT
BACKGROUND: Intensity modulated arc therapy (IMAT) has been widely adopted for Stereotactic Body Radiotherapy (SBRT) for lung cancer. While treatment dose is optimized and calculated on a static Computed Tomography (CT) image, the effect of the interplay between the target and linac multi-leaf colli...
Autores principales: | , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243813/ https://www.ncbi.nlm.nih.gov/pubmed/25365935 http://dx.doi.org/10.1186/s13014-014-0225-3 |
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author | Zou, Wei Yin, Lingshu Shen, Jiajian Corradetti, Michael N Kirk, Maura Munbodh, Reshma Fang, Penny Jabbour, Salma K Simone, Charles B Yue, Ning J Rengan, Ramesh Teo, Boon-Keng Kevin |
author_facet | Zou, Wei Yin, Lingshu Shen, Jiajian Corradetti, Michael N Kirk, Maura Munbodh, Reshma Fang, Penny Jabbour, Salma K Simone, Charles B Yue, Ning J Rengan, Ramesh Teo, Boon-Keng Kevin |
author_sort | Zou, Wei |
collection | PubMed |
description | BACKGROUND: Intensity modulated arc therapy (IMAT) has been widely adopted for Stereotactic Body Radiotherapy (SBRT) for lung cancer. While treatment dose is optimized and calculated on a static Computed Tomography (CT) image, the effect of the interplay between the target and linac multi-leaf collimator (MLC) motion is not well described and may result in deviations between delivered and planned dose. In this study, we investigated the dosimetric consequences of the inter-play effect on target and organs at risk (OAR) by simulating dynamic dose delivery using dynamic CT datasets. METHODS: Fifteen stage I non-small cell lung cancer (NSCLC) patients with greater than 10 mm tumor motion treated with SBRT in 4 fractions to a dose of 50 Gy were retrospectively analyzed for this study. Each IMAT plan was initially optimized using two arcs. Simulated dynamic delivery was performed by associating the MLC leaf position, gantry angle and delivered beam monitor units (MUs) for each control point with different respiratory phases of the 4D-CT using machine delivery log files containing time stamps of the control points. Dose maps associated with each phase of the 4D-CT dose were calculated in the treatment planning system and accumulated using deformable image registration onto the exhale phase of the 4D-CT. The original IMAT plans were recalculated on the exhale phase of the CT for comparison with the dynamic simulation. RESULTS: The dose coverage of the PTV showed negligible variation between the static and dynamic simulation. There was less than 1.5% difference in PTV V95% and V90%. The average inter-fraction and cumulative dosimetric effects among all the patients were less than 0.5% for PTV V95% and V90% coverage and 0.8 Gy for the OARs. However, in patients where target is close to the organs, large variations were observed on great vessels and bronchus for as much as 4.9 Gy and 7.8 Gy. CONCLUSIONS: Limited variation in target dose coverage and OAR constraints were seen for each SBRT fraction as well as over all four fractions. Large dose variations were observed on critical organs in patients where these organs were closer to the target. |
format | Online Article Text |
id | pubmed-4243813 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-42438132014-11-26 Dynamic simulation of motion effects in IMAT lung SBRT Zou, Wei Yin, Lingshu Shen, Jiajian Corradetti, Michael N Kirk, Maura Munbodh, Reshma Fang, Penny Jabbour, Salma K Simone, Charles B Yue, Ning J Rengan, Ramesh Teo, Boon-Keng Kevin Radiat Oncol Research BACKGROUND: Intensity modulated arc therapy (IMAT) has been widely adopted for Stereotactic Body Radiotherapy (SBRT) for lung cancer. While treatment dose is optimized and calculated on a static Computed Tomography (CT) image, the effect of the interplay between the target and linac multi-leaf collimator (MLC) motion is not well described and may result in deviations between delivered and planned dose. In this study, we investigated the dosimetric consequences of the inter-play effect on target and organs at risk (OAR) by simulating dynamic dose delivery using dynamic CT datasets. METHODS: Fifteen stage I non-small cell lung cancer (NSCLC) patients with greater than 10 mm tumor motion treated with SBRT in 4 fractions to a dose of 50 Gy were retrospectively analyzed for this study. Each IMAT plan was initially optimized using two arcs. Simulated dynamic delivery was performed by associating the MLC leaf position, gantry angle and delivered beam monitor units (MUs) for each control point with different respiratory phases of the 4D-CT using machine delivery log files containing time stamps of the control points. Dose maps associated with each phase of the 4D-CT dose were calculated in the treatment planning system and accumulated using deformable image registration onto the exhale phase of the 4D-CT. The original IMAT plans were recalculated on the exhale phase of the CT for comparison with the dynamic simulation. RESULTS: The dose coverage of the PTV showed negligible variation between the static and dynamic simulation. There was less than 1.5% difference in PTV V95% and V90%. The average inter-fraction and cumulative dosimetric effects among all the patients were less than 0.5% for PTV V95% and V90% coverage and 0.8 Gy for the OARs. However, in patients where target is close to the organs, large variations were observed on great vessels and bronchus for as much as 4.9 Gy and 7.8 Gy. CONCLUSIONS: Limited variation in target dose coverage and OAR constraints were seen for each SBRT fraction as well as over all four fractions. Large dose variations were observed on critical organs in patients where these organs were closer to the target. BioMed Central 2014-11-01 /pmc/articles/PMC4243813/ /pubmed/25365935 http://dx.doi.org/10.1186/s13014-014-0225-3 Text en © Zou et al.; licensee BioMed Central Ltd. 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Zou, Wei Yin, Lingshu Shen, Jiajian Corradetti, Michael N Kirk, Maura Munbodh, Reshma Fang, Penny Jabbour, Salma K Simone, Charles B Yue, Ning J Rengan, Ramesh Teo, Boon-Keng Kevin Dynamic simulation of motion effects in IMAT lung SBRT |
title | Dynamic simulation of motion effects in IMAT lung SBRT |
title_full | Dynamic simulation of motion effects in IMAT lung SBRT |
title_fullStr | Dynamic simulation of motion effects in IMAT lung SBRT |
title_full_unstemmed | Dynamic simulation of motion effects in IMAT lung SBRT |
title_short | Dynamic simulation of motion effects in IMAT lung SBRT |
title_sort | dynamic simulation of motion effects in imat lung sbrt |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243813/ https://www.ncbi.nlm.nih.gov/pubmed/25365935 http://dx.doi.org/10.1186/s13014-014-0225-3 |
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