Some Physical Factors Influencing the Distributions of Thermal Neutrons and Gamma-Rays in a Phantom

Abstract

In boron neutron capture therapy (BNCT), the distributions of thermal neutron fluence and capture γ-ray dose rates in the brain depend on various physical factors such as the spectrum of incident neutrons, the size of the neutron irradiation aperture, the geometry and dimension of the patient’s head and the ¹⁰B concentration in normal and tumor tissues. For successful BNCT, it is a prerequisite to provide distributions of both thermal neutrons and capture γ-ray dose rate which take into account the preceding physical factors. The present study evaluates the effect of these factors on the depth-dose distributions. The use of heavy water by partially deuterating the tissue is being considered for the BNCT of some deep-seated tumors. The effect on the distribution of various levels of deuteration was examined.