An accelerator-based epithermal photoneutron source for boron neutron capture therapy.

摘要

Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. At present BNCT research in both the United States and Europe emphasizes the necessity of an epithermal beam to generate the necessary thermal neutron field at the desired depth. Through the use of an epithermal beam, deeper-seated tumors can be treated more effectively. Boronated cells are selectively destroyed via energy deposition resulting from the ;Current usable beams are reactor-based, but a viable alternative is the production of an epithermal neutron beam using an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high energy photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of ;If BNCT is to become a wide-spread treatment modality, more neutron beam centers are needed worldwide to meet the treatment needs of all patients. With only reactor-based beams available, there could be a significant shortage of epithermal neutron beam facilities. Accelerator-based beam designs should be considered for the ultimate future of BNCT as a radiotherapy modality.