Neutron capture irradiations : principle, current results and prospects

Neutron capture irradiation aims to selectively destroy the tumoral cells with nuclear reactions produced inside themselves. Therefore, 10B is selectively carried into tumours, being linked to a molecular vehicle. The tissues are then irradiated with thermal neutrons, and the boron neutron capture leads to the formation of α and 7Li particles which produce high levels of radiolytic damage along their range of 10μm. Boron neutron capture therapy (BNCT) uses a thermal/epithermal neutron beam for irradiation, while boron neutron capture potentiation uses the addition of the captures in a fast neutron irradiation. A first trial, conducted in 1951 to 1961 in the USA to test BNCT on patients suffering of glioblastoma, was a failure, essentially because 10B was located in the cerebral capillaries rather than in the tumoral cells. Today, with great improvement in the boronated compounds which show an uptake preferentially inside the cells; the quality of neutron beams; and the knowledge of the microdosimetry of the technique, this technique may be clinically used to increase the local control of radioresistant tumours, like the high grade gliomas, cutaneous or uveal melanoma, and perhaps soft tissue sarcomas. (authors). 145 refs., 3 figs., 1 tab