Abstract
Boron Neutron Capture Therapy (BNCT) is based on the nuclear reaction that occurs when 10B loaded tissue is irradiated with thermal neutron yielding high linear energy transfer alpha particles and recoiling 7Li nuclei. Neutron sources for BNCT are currently limited to research nuclear reactors. However most reactors are not in close proximity to hospitals and their use for clinical trials can be difficult. High energy photon beams from medical Linear accelerators produce undesirable neutrons, beside the clinically useful electron and photon beams, neutrons are produced from the photonuclear reaction of high energy photons with high Z-materials making the accelerator head. Such neutrons have been studied extensively, both in measurements and Monte Carlo calculations mainly from the point of radiation protection. In this work the neutron component from high energy medical linear accelerator, dose, and fluence had been studied for the purpose of shielding patient, staff and the general public from the contaminant neutrons. In this work one major finding is the increase of neutron yield from the medical linac head when jaws are open compared when jaws are closed. Making use of already installed high energy linacs in hospitals used primarily for high energy electron and photon (bremsstrahlung) therapy for neutron production for use in BNCT will be advantageous in the sense that their use is much more acceptable to the public than the use of reactors. It will also mean fewer complications with respect to patient movement and management and will be cost effective. To consider the feasibility of this Monte Carlo simulation of a voxalized head phantom have been undertaken, comparing a reactor source to a medical linac source and comparing different moderator modalities.