[Safety Analysis Using Event Tree Analysis for Multi-Ion Therapy].

• DOI: 10.11323/jjmp.44.1_1
• Publication Date: 2024-01-01
• Authors: Sodai Tanaka; Taku Nakaji; Hideyuki Mizuno; Kota Mizushima; Ken Katagiri; Koki Kasamatsu; Takamitsu Masuda; Taku Inaniwa
• Keywords: Interlock; System safety

At the National Institutes for Quantum Science and Technology (QST), a multi-ion therapy using helium, carbon, oxygen, neon ions has been studied charged particle with more optimal biological effects. To make clinically feasible, new treatment system was developed to realize changes of ion species in each irradiation Heavy Ion Medial Accelerator Chiba (HIMAC). Since radiation is safety-critical, it necessary construct safety that includes multiple barriers perform analysis prevention serious accidents. In this study, we conducted event tree (ETA) newly introduced processes planning, accelerator, therapy. ETA an method verify are essential medical shorten time by focusing only on processes. Through ETA, clarified types malfunctions human errors may lead accidents therapy, verified whether such as interlock systems check procedures sufficient prevent errors. As result, 6 initial events which were listed planning process, 16 accelerator system, 13 system. Among these 35 events, 5 cautionary identified could final they had probability occurrence higher than 10