Study on the biological effects caused by neutron and charged-particle fragments on charged-particle radiotherapy

Neutrons emitted through spallation reaction inside a patient's body or beam delivery devices may cause significant acute or late biological effects to healthy tissues surrounding tumour target on charged particle therapy. The effects are, however, not yet investigated neither theoretically nor experimentally. This study aims at estimating the effects caused by fragment particles, especially by neutrons, through experimental approach. This year, response of a Bonner sphere was investigated in the field of therapeutic heavy ion beams. (author)