Cargando…

On the reduction of aperture complexity in kidney SABR

BACKGROUND: Stereotactic ablative body radiotherapy (SABR) of primary kidney cancers is confounded by motion. There is a risk of interplay effect if the dose is delivered using volumetric modulated arc therapy (VMAT) and flattening filter‐free (FFF) dose rates due to target and linac motion. This st...

Descripción completa

Detalles Bibliográficos
Autores principales: Gaudreault, Mathieu, Offer, Keith, Kron, Tomas, Siva, Shankar, Hardcastle, Nicholas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8035567/
https://www.ncbi.nlm.nih.gov/pubmed/33756036
http://dx.doi.org/10.1002/acm2.13215
_version_ 1783676726391341056
author Gaudreault, Mathieu
Offer, Keith
Kron, Tomas
Siva, Shankar
Hardcastle, Nicholas
author_facet Gaudreault, Mathieu
Offer, Keith
Kron, Tomas
Siva, Shankar
Hardcastle, Nicholas
author_sort Gaudreault, Mathieu
collection PubMed
description BACKGROUND: Stereotactic ablative body radiotherapy (SABR) of primary kidney cancers is confounded by motion. There is a risk of interplay effect if the dose is delivered using volumetric modulated arc therapy (VMAT) and flattening filter‐free (FFF) dose rates due to target and linac motion. This study aims to provide an efficient way to generate plans with minimal aperture complexity. METHODS: In this retrospective study, 62 patients who received kidney SABR were reviewed. For each patient, two plans were created using internal target volume based motion management, on the average intensity projection of a four‐dimensional CT. In the first plan, optimization was performed using a knowledge‐based planning model based on delivered clinical plans in our institution. In the second plan, the optimization was repeated, with a maximum monitor unit (MU) objective applied in the optimization. Dose‐volume, conformity, and complexity metric (with the field edge metric and the modulation complexity score) were compared between the two plans. Results are shown in terms of median (first quartile — third quartile). RESULTS: Similar dosimetry was obtained with and without the utilization of an objective on the MU. However, complexity was reduced by using the objective on the MUs (modulation complexity score = 0.55 (0.50–0.61) / 0.33 (0.29–0.36), P‐value < 10(−10), with/without the MU objective). Reduction of complexity was driven by a larger aperture area (area aperture variability = 0.68 (0.64–0.73) / 0.42 (0.37–0.45), P‐value < 10(−10), with/without the MU objective). Using the objective on the MUs resulted in a more spherical dose distribution (sphericity 50% isodose = 0.73 (0.69–0.75) / 0.64 (0.60–0.68), P‐value < 10(−8), with/without the MU objective) reducing dose to organs at risk given respiratory motion. CONCLUSIONS: Aperture complexity is reduced in kidney SABR by using an objective on the MU delivery with VMAT and FFF dose rate.
format Online
Article
Text
id pubmed-8035567
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher John Wiley and Sons Inc.
record_format MEDLINE/PubMed
spelling pubmed-80355672021-04-15 On the reduction of aperture complexity in kidney SABR Gaudreault, Mathieu Offer, Keith Kron, Tomas Siva, Shankar Hardcastle, Nicholas J Appl Clin Med Phys Radiation Oncology Physics BACKGROUND: Stereotactic ablative body radiotherapy (SABR) of primary kidney cancers is confounded by motion. There is a risk of interplay effect if the dose is delivered using volumetric modulated arc therapy (VMAT) and flattening filter‐free (FFF) dose rates due to target and linac motion. This study aims to provide an efficient way to generate plans with minimal aperture complexity. METHODS: In this retrospective study, 62 patients who received kidney SABR were reviewed. For each patient, two plans were created using internal target volume based motion management, on the average intensity projection of a four‐dimensional CT. In the first plan, optimization was performed using a knowledge‐based planning model based on delivered clinical plans in our institution. In the second plan, the optimization was repeated, with a maximum monitor unit (MU) objective applied in the optimization. Dose‐volume, conformity, and complexity metric (with the field edge metric and the modulation complexity score) were compared between the two plans. Results are shown in terms of median (first quartile — third quartile). RESULTS: Similar dosimetry was obtained with and without the utilization of an objective on the MU. However, complexity was reduced by using the objective on the MUs (modulation complexity score = 0.55 (0.50–0.61) / 0.33 (0.29–0.36), P‐value < 10(−10), with/without the MU objective). Reduction of complexity was driven by a larger aperture area (area aperture variability = 0.68 (0.64–0.73) / 0.42 (0.37–0.45), P‐value < 10(−10), with/without the MU objective). Using the objective on the MUs resulted in a more spherical dose distribution (sphericity 50% isodose = 0.73 (0.69–0.75) / 0.64 (0.60–0.68), P‐value < 10(−8), with/without the MU objective) reducing dose to organs at risk given respiratory motion. CONCLUSIONS: Aperture complexity is reduced in kidney SABR by using an objective on the MU delivery with VMAT and FFF dose rate. John Wiley and Sons Inc. 2021-03-23 /pmc/articles/PMC8035567/ /pubmed/33756036 http://dx.doi.org/10.1002/acm2.13215 Text en © 2021 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://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
Gaudreault, Mathieu
Offer, Keith
Kron, Tomas
Siva, Shankar
Hardcastle, Nicholas
On the reduction of aperture complexity in kidney SABR
title On the reduction of aperture complexity in kidney SABR
title_full On the reduction of aperture complexity in kidney SABR
title_fullStr On the reduction of aperture complexity in kidney SABR
title_full_unstemmed On the reduction of aperture complexity in kidney SABR
title_short On the reduction of aperture complexity in kidney SABR
title_sort on the reduction of aperture complexity in kidney sabr
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8035567/
https://www.ncbi.nlm.nih.gov/pubmed/33756036
http://dx.doi.org/10.1002/acm2.13215
work_keys_str_mv AT gaudreaultmathieu onthereductionofaperturecomplexityinkidneysabr
AT offerkeith onthereductionofaperturecomplexityinkidneysabr
AT krontomas onthereductionofaperturecomplexityinkidneysabr
AT sivashankar onthereductionofaperturecomplexityinkidneysabr
AT hardcastlenicholas onthereductionofaperturecomplexityinkidneysabr