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

• Published in: Physics in medicine & biology 1995-05, Vol.40 (5), p.807
• Main Authors: Allen, D A, Beynon, T D
• Format: Article
• Language: English
• Subjects: Biophysical Phenomena; Biophysics; Boron Neutron Capture Therapy - instrumentation; Equipment Design; Fast Neutrons; Humans; Models, Biological; Monte Carlo Method; Neoplasms - radiotherapy; Particle Accelerators - instrumentation; Protons; Radiotherapy Planning, Computer-Assisted
• ISSN: 0031-9155
• DOI: 10.1088/0031-9155/40/5/007

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 10(9) cm-2 s-1 and a neutron dose per unit fluence of less than 6 x 10(-13) Gy cm2, with a gamma-ray contamination of the therapy beam of about 10(-13) Gy cm2.