ESTRO 2025 - Abstract Book

S3645

Physics - Quality assurance and auditing

ESTRO 2025

exceeded 8%. For symmetry values less than 5% for both the ICP and EPID measurements, the percent difference was within 1.02% for 6MV and 2.19% for 16MV.

The maximum difference between ICP and the EPID was 0.25% for DR-GS and 0.36% for MLC leaf speed.

Conclusion: The AQA test suite was able to effectively detect errors, validating its use for clinical QA applications. The study framework, which compared the efficient EPID-based tests to more labor-intensive ICP tests, can be applied to commission other EPID-based QA systems with known errors, ensuring their reliability and supporting their integration into routine clinical practice.

Keywords: linac, automated, EPID

2759

Digital Poster Balancing safety and precision: dose assessment for Cone Beam CT in Radiotherapy through measurement and simulation Livia Marrazzo 1,2,3 , Adriana Taddeucci 4,3 , Chiara Arilli 2 , Claudia Poggiali 1 , Filippo Susini 1 , Carlotta Mozzi 1 , Laura Ceccarelli 1 , Sebastiano Paolucci 1 , Silvia Calusi 2 , Marta Casati 2 , Antonella Compagnucci 2 , Cinzia Talamonti 1,2,3 , Margherita Zani 2 , Stefania Pallotta 1,2,3 1 Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy. 2 Medical Physics Unit, Careggi University Hospital, Florence, Italy. 3 Istituto Nazionale di Fisica Nucleare, INFN, Florence, Italy. 4 Health Physics Unit, Careggi University Hospital, Florence, Italy Purpose/Objective: With the increasing prevalence of daily CBCT and a growing variety of imaging protocols, understanding the imaging dose delivered to the patient becomes essential, not only to enhance patient safety but also to support the selection of the optimal protocol tailored to specific imaging objectives. The purpose of this study is to measure dosimetric indices and estimate organ doses through simulations, enabling an accurate assessment of patient dose from CBCT in radiotherapy.

Material/Methods: