Systematic Risk Evaluation and Mitigation Strategies for Adaptive Pelvic Radiotherapy Using Cone Beam Imaging: Insights from Clinical Experience

Background: The integration of online adaptive radiotherapy (oART) using cone beam computed tomography (CBCT) has enhanced precision in treating pelvic malignancies by accounting for anatomical variations. However, this dynamic workflow introduces multifactorial risks requiring structured evaluation.Methods: A comprehensive failure mode and effects analysis (FMEA) was performed across multiple pelvic oART workflows using retrospective data from 68 patients treated over 20 months. High-risk processes were identified, and root cause analysis (RCA) was conducted to guide targeted interventions. Results: Key failure modes included incomplete structure propagation, registration mismatches, insufficient plan quality assurance, and inconsistent plan-of-the-day selections. Contributing factors ranged from software limitations to cognitive workload under time pressure. Corrective strategies included dual-user plan verification, enhanced training protocols, and structured checklists.Conclusion: oART introduces unique safety vulnerabilities requiring proactive risk management. Embedding FMEA and RCA into clinical implementation can enhance treatment consistency, reduce error rates, and support safe expansion of adaptive technologies in pelvic radiotherapy.