A Novel Deliverable Workflow for Dynamic Proton Arc Treatment
Abstract
Purpose
Proton arc therapy (PAT) faces two key challenges: minimizing treatment delivery time and eliminating gantry rotation velocity fluctuations. To address these, this study proposes a novel workflow that enables true dynamic arc delivery.
Methods
The real dynamic arc delivery workflow (referred to as PAT_va) comprises two key components: (i). an adaptive angular frequency proton arc planning strategy, which is generated through iterative linear programming to regulate gantry rotation velocity; and (ii) a novel dynamic arc delivery controller that fine-tunes gantry rotation velocity by modulating beam intensity to achieve maximum constant velocity delivery. Nine patients with brain, liver, and prostate cancers were selected for validation. Benchmarks included the previously published uniform-angular-frequency (PAT_ua) and the dynamic arc delivery controller prototype. Evaluation metrics included plan quality, dose delivery time, and the total variation in gantry rotation velocity.
Results
Both PAT_va and PAT_ua treatment plans satisfy the dosimetric criteria (D98≥95%, D2≤106%). Compared to PAT_ua, PAT_va achieved an increase in average gantry rotation velocity from 1.56 ± 0.10 to 2.02 ± 0.12 °/s, and gantry velocity variability dropped from 22.48 ± 3.94 °/s2 on average to nearly zero, p<0.01. Furthermore, the deliverable proton arc workflow reduced the average total delivery time per case by 16.0%, from 234.98 to 197.37 s (a reduction of 37.61 s, p<0.01).
Conclusion
This study proposes a novel workflow for proton arc plans with maximized constant gantry velocity, achieving true dynamic arc delivery for the first time.