Radiation shielding and patient organ dose study for an accelerator- based BNCT Facility at LBNL

摘要

This study considers the radiation safety aspects of several designs discussed in a previous report of an accelerator-based source of neutrons, based on the (sup 7)Li(p,n) reaction, for a Boron Neutron Capture Therapy (BNCT) Facility at Lawrence Berkeley National Laboratory (LBNL). determines the optimal radiation shield thicknesses for the patient treatment room. Since this is an experimental facility no moderator or reflector is considered in the bulk wall shield design. This will allow the flexibility of using any postulated moderator/reflector design and assumes sufficient shielding even in the absence of a moderator/reflector. In addition the accelerator is assumed to be capable of producing 100 mA of 2.5 MeV proton beam current. The addition of 1% and 2% (sup 10)B (by weight) to the concrete is also investigated. The second part of this paper determines the radiation dose to the major organs of a patient during a treatment. Simulations use the MIRD 5 anthropomorphic phantom to calculate organ doses from a 20 mA proton beam assuming various envisioned moderator/reflector in place. Doses are tabulated by component and for a given uniform (sup 10)B loading in all organs. These are presented in for a BeO moderator and for an Al/AlF(sub 3) moderator. Dose estimates for different (sup 10)B loadings may be scaled.