4-Boronophenylalanine (BPA) is one of only two boronated compounds approved for use in the US Phase I1 Clinical Trials for boron neutron capture therapy.'This therapy is dependent on the interaction of boron-I0 atoms with low energy (thermal) neutrons to generate cytotoxic alpha particles.'In an effort to determine the distribution of BPA in vivo utilizing both MR13 and positron emission tomography (PET):.'4-borono-2-fluorophenylalanine (1) was ...