Biodistribution of¹⁰B for Boron Neutron Capture Therapy (BNCT) in a Mouse Model after Injection of Sodium Mercaptoundecahydro-closo-dodecaborate and l-para-Boronophenylalanine

In boron neutron capture therapy, the absorbed dose from the B-10(n,alpha)Li-7 reaction depends on the B-10 concentration and B-10 distribution in the irradiated volume. Thus compounds used in BNCT should have tumor-specific uptake and low accumulation in normal tissues. This study compares in a mouse model the B-10 uptake in different organs as delivered by L-para-boronophenylalanine (BPA, 700 mg/kg body weight, i.p.) and/or sodium mercaptoundecahydro-closo-dodecaborate (BSH, 200 mg/kg body weight, i.p). After BSH injection, the B-10 concentration was high in kidneys (20 +/- 12 mu g/g) and liver (20 +/- 12 mu g/g) but was low in brain (1.0 +/- 0.8 mu g/g) and muscle (1.9 +/- 1.2 mu g/g). After BPA injection, the B-10 concentration was high in kidneys (38 +/- 25 mu g/g) and spleen (17 +/- 8 mu g/g) but low in brain (5 +/- 3 mu g/g). After combined BPA and BSH injection, the effect on the absolute B-10 concentration was additive in all organs. The ratio of the B-10 concentrations in tissues and blood differed significantly for the two compounds depending on the compound combination, which implies a different uptake profile for normal organs. (C) 2009 by Radiation Research Society