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Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer
PURPOSE: Position accuracy of the multi‐leaf collimator (MLC) is essential in stereotactic body radiotherapy (SBRT). This study is aimed to investigate the dosimetric impacts of the MU‐weighted MLC positioning uncertainties of SBRT for patients with early stage peripheral non‐small cell lung cancer...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769390/ https://www.ncbi.nlm.nih.gov/pubmed/33128499 http://dx.doi.org/10.1002/acm2.13061 |
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author | Feng, AiHui Chen, Hua Wang, Hao Gu, HengLe Shao, Yan Duan, YanHua Ying, YanChen Yue, Ning Jeff Xu, ZhiYong |
author_facet | Feng, AiHui Chen, Hua Wang, Hao Gu, HengLe Shao, Yan Duan, YanHua Ying, YanChen Yue, Ning Jeff Xu, ZhiYong |
author_sort | Feng, AiHui |
collection | PubMed |
description | PURPOSE: Position accuracy of the multi‐leaf collimator (MLC) is essential in stereotactic body radiotherapy (SBRT). This study is aimed to investigate the dosimetric impacts of the MU‐weighted MLC positioning uncertainties of SBRT for patients with early stage peripheral non‐small cell lung cancer (NSCLC). METHODS: Three types of MLC position error were simulated: Type 1, random error; Type 2, system shift, in which both MLC banks shifted to the left or right direction; and Type 3, in which both MLC banks moved with same magnitudes in the opposite directions. Two baseline plans were generated: an automatic plan (AP) and a manually optimized plan (MP). Multi‐leaf collimator position errors were introduced to generate simulated plans with the preset MLC leaf position errors, which were then reimported into the Pinnacle system to generate simulated plans, respectively. The dosimetric parameters (CI, nCI, GI, etc.) and gEUD values of PTV and OARs were calculated. Linear regression between MU‐weighted/unweighted MLC position error and gEUD was performed to obtain dose sensitivity. RESULTS: The dose sensitivities of the PTVs were −4.93, −38.94, −41.70, −55.55, and 30.33 Gy/mm for random, left shift, right shift, system close, and system open MLC errors, respectively. There were significant differences between the MU‐weighted and the unweighted dose sensitivity, which was −38.94 Gy/mm vs −3.42 Gy/mm (left shift), −41.70 Gy/mm vs −3.56 Gy/mm (right shift), −55.55 Gy/mm vs −4.84 Gy/mm (system close), and 30.33 vs 2.64 Gy/mm (system open). For the system open/close MLC errors, as the PTV volume became larger, the dose sensitivity decreased. APs provided smaller dose sensitivity for the system shift and system close MLC errors compared to the conventional MPs. CONCLUSIONS: There was significant difference in dose sensitivity between MU‐weighted and unweighted MLC position error of SBRT radiotherapy in peripheral NSCLC. MU is suggested to be included in the dosimetric evaluation of the MLC misalignments, since it is much closer to clinical radiotherapy. |
format | Online Article Text |
id | pubmed-7769390 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-77693902020-12-31 Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer Feng, AiHui Chen, Hua Wang, Hao Gu, HengLe Shao, Yan Duan, YanHua Ying, YanChen Yue, Ning Jeff Xu, ZhiYong J Appl Clin Med Phys Radiation Oncology Physics PURPOSE: Position accuracy of the multi‐leaf collimator (MLC) is essential in stereotactic body radiotherapy (SBRT). This study is aimed to investigate the dosimetric impacts of the MU‐weighted MLC positioning uncertainties of SBRT for patients with early stage peripheral non‐small cell lung cancer (NSCLC). METHODS: Three types of MLC position error were simulated: Type 1, random error; Type 2, system shift, in which both MLC banks shifted to the left or right direction; and Type 3, in which both MLC banks moved with same magnitudes in the opposite directions. Two baseline plans were generated: an automatic plan (AP) and a manually optimized plan (MP). Multi‐leaf collimator position errors were introduced to generate simulated plans with the preset MLC leaf position errors, which were then reimported into the Pinnacle system to generate simulated plans, respectively. The dosimetric parameters (CI, nCI, GI, etc.) and gEUD values of PTV and OARs were calculated. Linear regression between MU‐weighted/unweighted MLC position error and gEUD was performed to obtain dose sensitivity. RESULTS: The dose sensitivities of the PTVs were −4.93, −38.94, −41.70, −55.55, and 30.33 Gy/mm for random, left shift, right shift, system close, and system open MLC errors, respectively. There were significant differences between the MU‐weighted and the unweighted dose sensitivity, which was −38.94 Gy/mm vs −3.42 Gy/mm (left shift), −41.70 Gy/mm vs −3.56 Gy/mm (right shift), −55.55 Gy/mm vs −4.84 Gy/mm (system close), and 30.33 vs 2.64 Gy/mm (system open). For the system open/close MLC errors, as the PTV volume became larger, the dose sensitivity decreased. APs provided smaller dose sensitivity for the system shift and system close MLC errors compared to the conventional MPs. CONCLUSIONS: There was significant difference in dose sensitivity between MU‐weighted and unweighted MLC position error of SBRT radiotherapy in peripheral NSCLC. MU is suggested to be included in the dosimetric evaluation of the MLC misalignments, since it is much closer to clinical radiotherapy. John Wiley and Sons Inc. 2020-10-31 /pmc/articles/PMC7769390/ /pubmed/33128499 http://dx.doi.org/10.1002/acm2.13061 Text en © 2020 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Radiation Oncology Physics Feng, AiHui Chen, Hua Wang, Hao Gu, HengLe Shao, Yan Duan, YanHua Ying, YanChen Yue, Ning Jeff Xu, ZhiYong Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer |
title | Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer |
title_full | Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer |
title_fullStr | Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer |
title_full_unstemmed | Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer |
title_short | Effect of MU‐weighted multi‐leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non‐small cell lung cancer |
title_sort | effect of mu‐weighted multi‐leaf collimator position error on dose distribution of sbrt radiotherapy in peripheral non‐small cell lung cancer |
topic | Radiation Oncology Physics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769390/ https://www.ncbi.nlm.nih.gov/pubmed/33128499 http://dx.doi.org/10.1002/acm2.13061 |
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