An application of a cylindrical discharge tube type fusion neutron beam source for medical purpose was investigated. Practicality and possibility of the medical irradiation plan were evaluated from the standpoint of engineering and medicine.

Cancer treatment by BNCT (Boron Neutron Capture Therapy) was selected as an effective application to take advantage of this neutron source. Neutron transport in a phantom was calculated with the MCNP5 (Monte Carlo Neutron Particle calculation code version5), and the distribution of dose on the affected part medicated with a boron agent suggested satisfactory focusing.

Since this neutron source is small size, it is designed to irradiate the affected part from many directions by crossfire irradiation. Flexibility of attitude and operation modes permits irradiation in a supine position from arbitrary directions. Because of low neutron flux, irradiation therapy is planned for multi-fractionation in a manner similar to CHART (Continuous Hyperfractionated Accelerated Radio Therapy). Crossfire irradiation and CHART will allow us to achieve new cancer therapy with a relatively lower dose rate than conventional BNCT. It causes apoptosis selectively to a cancer cell, reducing side effects and a patient's recuperation burden. This result suggests the possibility of advanced cancer treatment which improves QOL (Quality of Life) of the patients.