Work

Evidence-based design of a patient-specific quality assurance program through retrospective analysis of pretreatment and in vivo results

Year: 2026

Type: article

Abstract: As radiotherapy techniques become increasingly complex, patient-specific quality assurance (PSQA) must evolve to detect a broad spectrum of potential failure modes across the treatment chain. This study presents a five-year retrospective analysis of an integrated PSQA framework implemented at Maastro Clinic, combining secondary dose calculations, log-file-based verification, and Electronic Portal Dosimetry (EPD) in both pretreatment and in vivo workflows. The performance of this framework was evaluated in the context of high-priority failure modes identified by the AAPM-ESTRO Failure Mode and Effects Analysis (FMEA).A total of 18,558 treatment plans were analyzed. Pretreatment secondary dose calculations identified algorithm-specific limitations, as well as discrepancies arising from unmodeled immobilization devices in the treatment planning system (TPS) and dose uncertainties due to small fields with jaw tracking. Log file and EPD pretreatment PSQA revealed additional plan transfer and deliverability issues, including rare cases of overmodulation. In vivo dose verification of 13,658 Cone Beam CT (CBCT) based fractions demonstrated that 21.19% of treatment plans exhibited at least one interfractional deviation, primarily related to patient setup, anatomical changes, or CBCT limitations. Intrafractional motion was detected in 0.50% of plans using in vivo EPD.Mapping these findings to the FMEA revealed that the combined PSQA framework effectively detected many failure modes, though limitations remained for errors rooted in TPS input data when also used for fitting PSQA dose calculation algorithms. The results underscore the value of multimodal PSQA and highlight opportunities for future enhancement e.g. using more clinically relevant evaluation metrics and dose accumulation of PSQA results.

Source: Physics and Imaging in Radiation Oncology

DOI: 10.1016/j.phro.2026.101106

Authors: Esther Decabooter, Sebastiaan M.J.J.G. Nijsten

Institution: Maastricht University Medical Centre

Language: English

Topic: Advanced Radiotherapy Techniques

Subfield: Radiation

Field: Physics and Astronomy

Domain: Physical Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $1,980