Purpose: To apply failure mode and effects analysis (FMEA) to the Volumetric-Modulated Arc Therapy (VMAT) technique for Total Body Irradiation (TBI) following TG-100 guideline.
Methods: A process map for VMAT TBI was developed following the AAPM TG-100 guidelines. This process map gives a visual representation of the flow of steps in the treatment process from the initial simulation, treatment planning, and treatment delivery. From the process map, all potential failure modes in the process were identified. Evaluation of the occurrence (O), detectability (D), and severity of impact (S) of each failure mode according to scoring criteria (1-10) by radiation oncology staff members was carried out. Subsequent calculation of the risk priority number (RPN = O x D x S) and identification of effective quality assurance methods for the highest risks proceeded evaluation.
Results: A total of 26 failure modes were derived. Five failure modes (top 20%), identified as being high-risk were (1) CBCT patient positioning check failure (2) the treatment planning system reports incorrect MUs after re-optimization (3 )incorrect patient set-up SSDs recorded in the record-and-verify system (4) patient movement during treatment and (5) organs-at-risk are contoured incorrectly, producing an inaccurate dose to critical structures. Further quality assurance and quality control measures were proposed to improve effectiveness of the procedure.
Conclusion: Quality assurance and quality control interventions were implemented based on the FMEA results. Further checks of the treatment planning system reported dose, patient contouring, patient positioning and of the record-and-verify system were proposed to improve the effectiveness of the treatment procedure.
Not Applicable / None Entered.