Document Type

Conference Proceeding

Publication Date

9-2024

Abstract

Purpose: To quantitatively assess the impact of random gantry rotation perturbations on spot-scanning arc (SPArc) therapy.

Methods:

To simulate random gantry rotation perturbations, the initial gantry angle of SPArc treatment plans was modified using an in-house script. Four cases from different disease sites include brain, lung, liver and prostate were selected to evaluate. Original SPArc plans (SPArcorg) were developed through iterative processes, including control point re-sampling, redistribution of control points & energy layers, energy layer filtration, and re-sampling. Considering potential limitations, rotation perturbations of 1mm and 2mm were applied to al SPArcorg plans to generate perturbed SPArc plans. These perturbations were analyzed both with and without Gaussian distribution. The effects on SPArc plans were evaluated using dosimetric parameters and the gamma-index passing ratio (GPR).

Results:

GPR results are presented in Table 1. For randomized rotation perturbations of 1mm and 2mm, SPArc plans demonstrated feasible GPRs exceeding 96% for both 3%/3mm and 2%/2mm measurement criteria. Remarkably, SPArc plans maintained a GPR of 91.87%±7.17% even under the strictest measurement criterion of 1%/1mm. For rotation perturbations of 1mm and 2mm with Gaussian distribution, SPArc plans achieved acceptable outcomes, with GPRs of 99.81%±0.15% and 98.55%±0.77% for 2mm/2% criteria, respectively.

Conclusion:

SPArc has shown its “robustness” for gantry rotation perturbations. Also, this study provides valuable quantitative data to the future quality assurance investigations for SPArc.

Volume

51

Issue

9

First Page

6653

Comments

American Association of Physicists in Medicine 66th Annual Meeting & Exhibition, July 21-25 2025, Los Angeles, CA

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