ESTRO-EPTN guidelines for independent dose calculation and log file-based patient specific quality assurance in scanned particle therapy

Independent dose calculation (IDC) and log file-based patient-specific quality assurance (PSQA) are increasingly used in scanned particle therapy (PT) to address pitfalls of phantom-based verifications. Highly modulated treatment fields, steep dose gradients, and growing interest for adaptive treatments require quality assurance (QA) approaches that are cost effective, patient-specific, and closely linked to the delivered treatment. Practical guidance is therefore needed for the safe clinical implementation of IDC- and log file-based PSQA. The ESTRO-EPTN (European Particle Therapy Network) developed consensus-based recommendations on IDC- and log file-based PSQA in PT. Current clinical practice, commissioning strategies, risk-management approaches, and available technical solutions were evaluated. Following a review of the literature, expert-based guidelines were developed covering clinical scopes, acceptance, commissioning and validation, integration with machine QA, data management, governance, and staged implementation. IDC- and log file-based PSQA were identified as complementary elements within a quality-management framework. Log file-based approaches enable evaluation of the delivered treatment fraction(s), while IDC provides computational verification of the planned dose. When appropriately validated, these methods increase sensitivity to potentially clinically relevant deviations and can substantially reduce reliance on phantom-based measurements. Safe application requires robust machine QA, characterization of model limitations, risk analysis, and data traceability. Recommendations applicable to all centers were developed for IDC. Log file-based PSQA recommendations include minimum requirements for the vendors. These recommendations aim to promote consistent and safe adoption across PT centers, while preserving the need for machine QA.