Relative biological effectiveness of thermal neutron capture therapy of malignant melanoma using para-boronophenylalanine: Comparison with electron irradiation

Since 1972, others have developed and established selective thermal neutron capture therapy in the treatment of malignant melanomas. This therapy utilizes the melanoma cells' specific cellular functional differentiation, that is, accelerated melanin synthesis. The authors have been analyzing the biologic effectiveness of thermal neutron capture therapy in tumors and surrounding skin of melanoma-bearing hamsters using the B-10-labeled dopa analogue (B/sub 1/-10-para-boronphenylanine hydrochloride; B/sub 1/-10-BPA.HCl) which selectively accumulates into melanoma cells. They report the RBE of their capture therapy for melanomas in comparison with electron beam therapy, using tumor growth delay time as the parameter. Total RBE as determined experiment ally was about 1.8. They further estimated the RBE of α-particle and Li-7 atom induced by B-10(n, α)Li-7 reaction with calculations (about 2.5)