Nuclear reactions induced by deuterons and their applicability to skin tumor treatment through BNCT

In this work the D(d,n)3He and 9Be(d,n)10B reactions have been studied in a low-energy regime as neutron sources for skin tumor treatment in the frame of accelerator-based BNCT (AB-BNCT). The total neutron production and the energy and angular distributions for each reaction at different bombarding energies and for the thick targets considered (TiD2, Be) have been determined using the available data in the literature. From this information, a feasibility study has been performed by means of MCNP simulations. The thermal, epithermal and fast neutron fluxes and doses at skin tumor positions (loaded with 40 ppm 10B) which are located on a whole-body human phantom have been simulated for different D2O moderator depths. The best-case performance shows that a high tumor control probability (TCP) of 99% corresponding to a weighted dose in tumor of 40 Gy can be reached at the tumor position keeping the weighted dose in healthy tissue below 12.5 Gy, by means of the 9Be(d,n)10B reaction at 1.1 MeV for a deuteron current of 20 mA and a 30 cm D2O moderator in 52 min. The availability of low-energy neutrons in the 9Be(d,n)10B reaction from the population of excited levels between 5.1 to 5.2 MeV in 10B and the convenience of a thin beryllium target are discussed.As a complement concerning alternatives to the Li(metal) + p reaction, the neutron yield of refractory lithium compounds (LiH, Li3N and Li2O) were calculated and compared with a Li metal target.