Radiobiological evaluation of 10B1-para-boronophenylalanine for thermal neutron capture therapy of malignant melanoma

Comparative radiobiological analysis of specific or enhancing killing effects of thermal neutron used with 10B1-para-boronophenylalanine (10B1-BPA) on B-16 melanoma cells was performed. As a result, marked enhancing killing effects of thermal neutron used with 10B1-BPA Do value, 0.9 - 1.2 x 1012 n/cm2 was recognized, while Do value of neutron alone was 2.8 x 1012 n/cm2. Since high LET irradiation was introduced into radiotherapy, its better energy deposition in the target cancer cells has been one of the major problems to be solved. This can be achieved in the order of cellular dimension if organic compounds possessing an excellent capacity to seek tumors could have been obtained. The result of this experiment seemed to indicate that 10B1-BPA could concentrate 10B into melanoma cells (11 times as high as the concentration of 10B in pre-incubation medium). (Tsunoda, M.)