KEY POINTS
- Retrospective dosimetric comparison of 14 patients treated with brass aperture-enhanced proton pencil beam scanning stereotactic radiosurgery for cerebral arteriovenous malformations between 2023 and 2025.
- Three patients received staged treatment, giving 17 treatment plans for analysis; mean arteriovenous malformation volume was 8.8 cm³ with a range of 0.4-30.6 cm³.
- Photon volumetric modulated arc therapy stereotactic radiosurgery plans were generated for comparison and normalized to match clinical target volume prescription coverage of the delivered proton plan.
- Proton plans reduced total brain V12 Gy in 15 of 17 plans (88.2%), with an average V12 Gy improvement of 5.86 cm³ compared with photon stereotactic radiosurgery.
- Homogeneity index and V12 Gy significantly favored protons, with p = 0.0034 and p = 0.0017, respectively; no significant conformity index difference was reported.
CLINICAL TAKEAWAY
This study suggests that brass aperture-enhanced proton pencil beam scanning stereotactic radiosurgery may reduce intermediate-dose exposure to normal brain for selected cerebral arteriovenous malformations, including small lesions and lesions near the brainstem. The evidence remains dosimetric and hypothesis-generating: the cohort was small, plan-level analysis included staged cases, photon plan quality is institution-dependent, and clinical outcomes such as obliteration and symptomatic radionecrosis are not yet mature.