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Dosimetric comparison of MR-guided adaptive IMRT versus 3DOF-VMAT for prostate stereotactic radiotherapy

Authors :
Vickie C. Kong
Jennifer Dang
Winnie Li
Inmaculada Navarro
Jerusha Padayachee
Victor Malkov
Jeff Winter
Srinivas Raman
Alejandro Berlin
Charles Catton
Padraig Warde
Peter Chung
Source :
Technical Innovations & Patient Support in Radiation Oncology, Vol 21, Iss , Pp 64-70 (2022)
Publication Year :
2022
Publisher :
Elsevier, 2022.

Abstract

Introduction: To compare the dosimetry of prostate stereotactic radiotherapy (SBRT) delivered by adaptive intensity modulated radiotherapy (A-IMRT) and 3 degree of freedom volumetric modulated arc therapy (3DOF-VMAT). Methods & Materials: Twenty-five prostate patients treated with High Dose Rate (HDR) brachytherapy followed by SBRT were included (fifteen with hydrogel spacer in place for treatment). Interfraction changes in the volume of prostate, rectum and bladder were measured. Fractional dose to these structures was estimated for A-IMRT and 3DOF-VMAT for comparison against the corresponding reference dose and between each other. Results: Clinically acceptable dose was delivered to prostate in all 125 fractions through A-IMRT and 3DOF-VMAT. A-IMRT was better than 3DOF-VMAT in reducing dose to 1 cm3 of rectum. Conversely, 3DOF-VMAT was superior in sparing 50% and 20% of rectum. When comparing the reference and delivered dose, there was no significant difference for Bladder D5cm3 for either technique. However, rectum in the high dose region benefited more from A-IMRT by being irradiated to a lower than reference dose in more fractions than 3DOF-VMAT. Hydrogel spacer reduced the rectal dose and was associated with a smaller deviation from reference dose for rectum D50% for A-IMRT. Conclusions: Despite the presence of large interfraction organ volumes changes, clinically acceptable dose was delivered to the prostate by both systems. A-IMRT facilitated a greater rectal sparing from the high dose region than 3DOF-VMAT. Further reduction in rectal dose could be achieved by hydrogel spacer to displace the rectum, or by adaptation delivered by VMAT.

Details

Language :
English
ISSN :
24056324
Volume :
21
Issue :
64-70
Database :
Directory of Open Access Journals
Journal :
Technical Innovations & Patient Support in Radiation Oncology
Publication Type :
Academic Journal
Accession number :
edsdoj.b4ec8b5e0b004e108bd8adfba96539ae
Document Type :
article
Full Text :
https://doi.org/10.1016/j.tipsro.2022.02.003