ESTRO 2025 - Abstract Book

S3626

Physics - Quality assurance and auditing

ESTRO 2025

necessitated by higher measurement uncertainties. In contrast, LFQA allows for stricter 3D Gamma criteria and resulted in more detections, largely aligning with TPS-based expectations (Fig. 2B).

Conclusion: Phantom-less PSQA exhibited superior sensitivity, detecting more errors in a fraction of the time required for phantom-based measurements. Stricter and more localized passing criteria can be applied at spot-level during LFQA, enhancing error cause identification, which is especially important when implementing reduced uncertainty margins. Automated PL-PSQA also represents a key requirement for online-adaptive PT.

Keywords: Patient-specific QA, Proton therapy