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Lookup NU author(s): JJ Wyatt, Dr Judith Mott
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 The AuthorsPurpose: Multiple brain metastases can be treated efficiently with stereotactic radiosurgery (SRS) using a single-isocenter dynamic conformal arc (SIDCA) technique. Currently, plans are manually optimized, which may lead to unnecessary table angles and arcs being used. This study aimed to evaluate an automatic 4π optimization SIDCA algorithm for treatment efficiency and plan quality. Methods and Materials: Automatic 4π-optimized SIDCA plans were created and compared with the manually optimized clinical plans for 54 patients who underwent single-fraction SRS for 2 to 10 metastases. The number of table angles and number of arcs were compared with a paired t test using a Bonferroni-corrected significance level of P < .05/4 = .0125. The reduction in treatment time was estimated from the difference in the number of table angles and arcs. Plan quality was assessed through the volume-averaged inverse Paddick Conformity Index (CI) and Gradient Index (GI) and the volume of normal brain surrounding each metastasis receiving 12 Gy (local V12 Gy). For a 5-patient subset, the automatic plans were manually adjusted further. CI and GI were assessed for noninferiority using a 1-sided t test with the noninferiority limit equal to the 95% interobserver reproducibility limit from a separate planning study (corrected significance level P < .05/[4 − 1] = .017). Results: The automatic plans significantly improved treatment efficiency with a mean reduction in the number of table angles and arcs of −0.5 ± 0.1 and −1.3 ± 0.2, respectively (±SE; both P < .001). Estimated treatment time saving was −2.7 ± 0.5 minutes, 14% of the total treatment time. The volume-averaged CI and GI were noninferior to the clinical plans (both P < .001), although there was a small systematic shift in CI of 0.07 ± 0.01. The resulting difference in local V12 Gy, 0.25 ± 0.04 cm3, was not clinically significant. Minor manual adjustment of the automatic plans removed these slight differences while preserving the improved treatment efficiency. Conclusions: Automatic 4π optimization can generate SIDCA SRS plans with improved treatment efficiency and noninferior plan quality.
Author(s): Wyatt JJ, Mohanraj R, Mott JH
Publication type: Article
Publication status: Published
Journal: Advances in Radiation Oncology
Year: 2024
Volume: 9
Issue: 8
Print publication date: 01/08/2024
Online publication date: 08/05/2024
Acceptance date: 29/03/2024
Date deposited: 25/07/2024
ISSN (electronic): 2452-1094
Publisher: Elsevier Inc.
URL: https://doi.org/10.1016/j.adro.2024.101538
DOI: 10.1016/j.adro.2024.101538
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