DNA damage and biological responses induced by Boron Neutron Capture Therapy (BNCT).

Boron Neutron Capture Therapy (BNCT) is a tumor cell selective high LET (linear energy transfer) particle beam therapy. The patient is administrated a boron (B) compound via intravenous injection or infusion, and when B is sufficiently accumulated in the tumor, neutron beams containing epithermal neutrons as the main component are irradiated. Epithermal neutrons lose energy in the body and become thermal neutrons. The captured B undergoes a (n, α) reaction with thermal neutrons, and the resulting α particles and Li nuclei have short ranges of 9-10μm and 4-5μm, respectively, and do not reach the surrounding cells in normal tissues. Therefore, these high LET-heavy charged particles can selectively kill cancer cells. The cell-killing effect of these heavy charged particles is thought to be triggered by DNA damage. It is known that DNA damage caused by heavy charged particles is more serious and difficult to repair than DNA damage caused by Low LET radiation such as X-rays and γ-rays. This review focuses on DNA damage, e.g., DNA strand breaks and DNA damage repair caused by BNCT and describes the resulting biological response.