Neutron Penetration During Neutron Capture Therapy

Abstract

Neutron transport theory was applied to the problem of penetration of a broad beam of neutrons into finite and semi-infinite volumes of aqueous media. Expressions derived are in excellent agreement with data obtained using a human head phantom of tissue equivalent gel. Epithermal neutrons are much more penetrating than thermal neutrons and thus more advantageous for neutron capture therapy. The presence of 0.02% B in the gel further increased the advantage of epithermal neutrons while diminishing flux only slightly.