A design study for an accelerator-based epithermal neutron beam for BNCT

Authors:   Allen D. A., Beynon T. D.
Journal: Physics in Medicine and Biology
https://dx.doi.org/10.1088/0031-9155/40/5/007
Abstract: An achievable design concept for a boron neutron capture therapy (BNCT) facility, based on a high-current, low-energy proton accelerator, is described. Neutrons are produced within a thick natural lithium target, under bombardment from protons with an initial energy between 2.5 and 3.0 MeV. The proton current will be up to 10 mA. After gamma -ray filtering, the neutrons are partially moderated to epithermal energies within a heavy-water moderator, poisoned with 6Li to remove thermal neutrons. Monte Carlo modelling has been used to predict system performance in terms of neutron fluence rate and neutron and gamma -ray dose at the patient position. The relationship between the system performance and key parameters, such as proton energy, moderator depth and 6Li concentration, has been investigated. With a proton current of 10 mA, the facility is capable of providing a therapy beam with a useful neutron fluence rate of 109 cm-2 and a neutron dose per unit fluence of less than 6*10-13 Gy cm2, with a gamma -ray contamination of the therapy beam of about 10-13 Gy cm 2.