Cancer cells are surrounded by normal cells. A targeted therapy using neutrons, which kills only cancer cells, has been carried out at Kyoto University’s Research Reactor Institute (KUR). Boron Neutron Capture Therapy (BNCT) uses the effect of the 10B(n,α)7 Li reaction to selectively destroy cancer cells injected with boron-10 compound. I have performed a study that aims to improve the effect of BNCT, and investigated DNA damage in the human body caused by neutron radiation. I found that Vitamin C is effective in protecting the human body from the effects of neutron radiation, which is has a greater effect on the human body than x-ray radiation. I aim to develop a neutron treatment for cancer with few side effects.