Retrospective evaluation of patient-specific intensity-modulated radiotherapy plan verification data in a single department

Objective: This study aims to retrospectively analyze and evaluate patient-specific quality assurance (QA) data from radiotherapy plans using Intensity-Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) techniques at Akdeniz University Department of Radiation Oncology between 2017 and 2023. Methods: QA data from 1574 treatment plans for 1078 patients were reviewed. Treatment plans were generated using PRECISE TPS for static IMRT and MONACO TPS for dynamic IMRT/VMAT techniques. Gamma index analysis was performed using MatriXX with a 3%/3 mm acceptance criterion. Data was categorized based on disease location, treatment devices, and planning systems, then statistically analyzed using Google Sheets and Looker Studio. Results: Throughout this survey, no QA data was available for the year 2021 due to equipment upgrades. The anatomical distribution of plans was head-neck (496), pelvis (492), thoracic (542), abdomen (31), vertebra (10), femur (2). Most frequently applied techniques included 9-field IMRT (31.9%), dual-arc VMAT (23.3%), and single-arc VMAT (19.4%). Mean ± SD Gamma pass rates were 97.29% ± 1.60 for IMRT (356 plans) and 99.13% ± 1.10 for VMAT (1012 plans). Conclusion: Both treatment planning systems (TPSs) yielded high gamma pass rates, indicating a high level of treatment delivery accuracy and reliability. VMAT usage increased over time due to its compatibility with equipment and precise dose delivery.