ESTRO 2025 - Abstract Book

S3672

Physics - Quality assurance and auditing

ESTRO 2025

Conclusion: Dosimetric changes due to our MLC positional errors in the evaluated cases have no relevant clinical implications. There is no agreement between international protocols or justifications on what tolerances should be used for MLC positional accuracy. A few examples are NCS [2], AAPM [3], and SEFM [4]. More research should be conducted on this topic to evaluate whether these tolerances may or may not prevent clinically relevant delivery errors that could not be detected with standard pre-treatment verification measurements/metrics. References: [1] Létourneau D, Wang A, Amin MN, et al. Multileaf collimator performance monitorin and imporvement using semiautomated quality control testing and statistical process control. Med Phys. 2014;41(12):121713 [2] Report 24 of the Netherlands Commission on Radiation Dosimetry, Code of Practice for the quality assurance and control for Volumetric Modulated Arc Therapy, February 2015. [3] Klein EE, Hanley J, Bayouth J, et al. Task Group 142 report: Quality assurance of medical accelerators. Med Phys.2009;36:4197 [4] SEFM. Guide for quality control and safety in clinical use linear accelerators. Rev Fis Med, 2024;25:77-122. Digital Poster Dose-volume histogram-based index for objective assessment of radiotherapy treatment plans: Application to breast cancer patients Hiran CG Maladenige 1,2 , Jan Seppälä 2 , Tuomas Virén 2 , Juuso TJ Honkanen 2 , Janne Heikkilä 2 , Akseli Leino 1,2 , Henri Korkalainen 1,2 1 Department of Technical Physics, University of Eastern Finland, Kuopio, Finland. 2 Center of Oncology, Kuopio University Hospital, Kuopio, Finland Purpose/Objective: The advancement of radiotherapy techniques has increased the complexity of the treatment planning process, leading to increased variability and subjectiveness in treatment plans. These problems fuel the current research trend in deep learning-based automatic treatment planning solutions[1]. However, plan evaluation and comparison Keywords: MLC, Leaf positioning error, Dosimetric impact 3650