Safety Analysis Using Event Tree Analysis for Multi-Ion Therapy

In this study, we conducted a safety analysis using event tree analysis (ETA) for newly introduced processes in the treatment planning, accelerator, and irradiation system of the multi-ion therapy. ETA is an optimal method to verify multiple safety barriers that are essential for medical safety and to shorten the time for safety analysis by focusing only on the new processes. Through ETA, we clarified the types of malfunctions and human errors that may lead to serious accidents in the new system for multi-ion therapy, and verified whether safety barriers such as interlock systems and human check procedures are sufficient to prevent such malfunctions and human errors. As a result, 6 initial events which may lead to serious accidents were listed in the treatment planning process, 16 initial events were listed in the accelerator system, and 13 initial events were listed in the irradiation system. Among these 35 initial events, 5 cautionary initial events were identified that could lead to serious final events and they had a probability of occurrence higher than 10-4. Meanwhile, the others were all initial events that do not lead to serious accidents, or the initial events that can lead to serious accidents but were considered to have sufficient safety barriers. The safety analysis using ETA successfully identified the system malfunctions and the human errors that can lead to serious accidents, and the multiple safety barriers against them were systematically analyzed. It became ...
Source: Igaku Butsuri: Japanese Journal of Medical Physics - Category: Physics Authors: Source Type: research