Proton Bragg peak flash stereotactic radiosurgery for recurrent glioblastoma reirradiation
- Journal
- Physics and imaging in radiation oncology (Q1)
- Published
- 20 July 2026
- Study design
- Unclassified
- Evidence level
- Level 5, Expert Opinion (CEBM 5)
- Authors
- Yangguang Ma, Yuyu Wang, Tengda Zhang, Xingyi Zhao, Balaji Selvaraj, Chingyun Cheng, et al.
- PMID
- 42630800
- DOI
- 10.1016/j.phro.2026.101044
Why clinicians should know about it
- Picked for Medical Physics (paper of the day, 24 August 2026): Proton FLASH technique evaluated for re‑irradiation of glioblastoma
Abstract
BACKGROUND AND PURPOSE: Stereotactic Radiosurgery with robotic image-guided systems is promising for recurrent glioblastoma (rGBM), but long delivery times may increase morbidity and reduce accuracy. Proton single-energy Bragg-peak FLASH-RT (SEBP-FLASH) may address these limits by delivering each field in <1 s, with potential for normal-tissue sparing through the FLASH effect. MATERIALS AND METHODS: The SEBP-FLASH technique was used to reoptimize treatment for rGBM patients treated with robotic image-guided systems. Patient-specific aperture devices were incorporated into the SEBP-FLASH technique for sharper penumbra. The gross tumor volume (GTV) coverage, conformity index (CI), dose gradient index (GI50 and GI30), and dose-volume histogram (DVHs), were evaluated. Additionally, ultra-high dose-rate ratios in critical organs-at-risk were assessed. RESULTS: SEBP-FLASH successfully met all clinical objectives. Both SEBP-FLASH and robotic techniques showed comparable performance, with GI50 and GI30 values of 2.9 ± 0.5 and 6.2 ± 1.8 for SEBP-FLASH, versus 2.7 ± 0.2 and 5.5 ± 0.5 for robotic (p-values at 0.085 and 0.189). SEBP-FLASH demonstrated superior conformality, achieving a CI of 1.4 ± 0.2 compared to CK's 1.9 ± 0.3 (p-value 0.001). All other metrics were similar across both techniques. For the brain, the FLASH dose rate coverage (V40 Gy/s) exceeded 80% under a 5 Gy dose threshold and minimum monitor unit of 400. CONCLUSIONS: This study evaluated the dose-volume characteristics of SEBP-FLASH and robotic image-guided systems and found broadly comparable dose distributions, suggesting that SEBP-FLASH may be a feasible option for rGBM reirradiation. SEBP-FLASH also showed potential advantages in conformity, normal tissue sparing, and reduced on-table time.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.