Neutron capture therapy for cancer

Boron neutron capture therapy (BNCT) is an selective radiotherapy using boron-10 which absorbs thermal neutrons and releases high LET α particles by 10B(n, α)7Li reaction. In this paper, the present status of BNCT for malignant melanoma was introduced. As a melanoma-targetting 10B-compound, 10B-paraboronophenylalanine (BPA) was used. It was administered by multiple subcutaneous injection or intravenous drip infusion. We adopted the maximum tolerance dose to the skin as a therapeutic dose regardless of the tumor 10B concentration, because we cannot directly measure it. For this purpose, an approximation of skin concentration was made using blood data just after the administration. We treated 14 melanoma patients in this way and obtained good local control of the tumor with tolerable skin reaction. More experience with logical analysis and basic research is necessary for further development of this therapy. (author)