Optimization of Beam Shaping Assembly design for Boron Neutron Capture Therapy based on a transportable proton accelerator.

Abstract The optimization of a Beam Shaping Assembly design for Boron Neutron Capture Therapy (BNCT), based on a commercial available proton accelerator, has been simulated. The primary goal is to improve the flux of the epithermal neutrons, which is the major drawback in all designed BNCT facilities with portable neutron source, satisfying simultaneously all the other relevant parameters. A BNCT facility has been simulated using the MCNP4B Monte Carlo code. A wide set of material were examined as moderators, while three different materials are used as fast neutron, gamma ray and thermal neutrons filters. Fast neutrons from ⁹Be(p,n)⁹B reaction are moderated through the ⁷LiF and TiF 3 moderators and further reduced using ⁶⁰Ni as fast neutron filter. The undesired gamma rays and thermal neutrons are removed using Bi and Cd filters respectively. The therapeutic efficacy of the proposed facility was calculated through the dosimetric evaluation in a head phantom. According to the results of the calculations the proposed unit satisfies the recommended by IAEA parameters. Only the flux of the epithermal neutrons remains below the recommended threshold, but is significantly improved. [ABSTRACT FROM AUTHOR]