NEUTRON-CAPTURE THERAPY

Neutron capture therapy (NCT) aims at destroying tumoral cells selecti vely labeled by (10)boron. B-10 has a very high cross section for ther mal neutron capture, and the nuclear reaction leads to the production of an alpha-particle and a Li-7 recoil ion, which carry an energy of 1 .47 and 0.85 MeV, respectively. The radiobiological advantages lie in the production of high-LET particles inside the cell, leading to a hig her relative biological effectiveness (RBE) of the irradiation. Despit e a first failure during the 50's in the U.S.A., the long survivals ob tained by H. Hatanaka for high grade gliomas have led to a renewal of the research and of the clinical trials. Hatanaka's clinical results h ave been confirmed since then by those of Y. Mishima on melanoma. This paper focuses on the present status of the research and of the clinic al trials of NCT, on the progress in boronated molecules and in neutro n sources, and finally on the tumoral localization which could potenti ally benefit of this technique.