Measurement of Relative Biological Effectiveness (RBE) for the Radiation Beam from Neutron Source Reactor YAYOI —Comparisons with Cyclotron Neutron and ⁶⁰Co Gamma Ray—

Abstract

Radiation biology and/or therapy research and development for a research reactor beam need specific RBEs of neutrons as well as of specific reactions. RBEs for reactor beams measured in situ condition are interesting because actual radiation effects on each biological system are different depending on detailed conditions of irradiation. A small powered research reactor (Fast Neutron Source Reactor: YAYOI) was examined here as a neutron beam source for obtaining survival curves in a manner usually done for cyclotron neutron source and ⁶⁰Co gamma rays. Chinese Hamster Cells were chosen as a sample system for comparison among them.
With an assumption of independence among individual radiation (neutron and gamma ray) effects and with the nearly equal survival fraction relation for ⁶⁰Co and reactor gamma, all the data taken for different radiation field were found to be fitted by a single curve with a set of Do and m value for the hit theory.