Distributions of β+ decayed nuclei generated in the CH2 and H2O targets by the target nuclear fragment reaction using therapeutic MONO and SOBP proton beam

摘要: In protonradiotherapy, the irradiation dose can be concentrated on a tumor. To use this radiotherapy efficiently in clinical field, it is necessary to evaluate proton-irradiated area and condition. The confirmed by coincidence detection of pair annihilation gamma rays from β + decayed nuclei generated target nuclear fragment reaction irradiated proton target. study, we performed experiments polyethylene ( PE : CH 2 ) containing C 12 nuclei, which major component human body, gelatinous water H O 16 at different energy levels under beam conditions mono-energetic Bragg peak spread-out peak. distribution activity after was measured positron emission tomography(PET) apparatus, compared with calculated distribution. temporal dependence during period between completion start measurement PET apparatus examined. 3 kB ∕ cc 13 target, indicating that intensity sufficient for evaluation range against physical short (several millimeter equivalent length), presence dependence. difference slightly large time until measurement. lateral widths full width half maximum distributions within 1 mm .