RESUMO
In this study, the calculations of proton emission spectra produced by 58Ni (n, xp) and 60Ni (n, xp) reactions are used in the framework of preequilibrium models with the EMPIRE and TALYS codes. Exciton Model predictions combined with the Kalbach angular distributions systematics, quantum-mechanical preequilibrium models (Multi-step Direct (MSD) theory and Multi-step Compound (MSC) processes) were used, and some necessary parameters have been investigated for our calculations. The comparison with experimental data shows clear improvement over the Exciton and quantum-mechanical preequilibrium models calculations.
RESUMO
The development of a medical facility for boron neutron capture therapy at Budker Institute of Nuclear Physics is under way. The neutron source is based on a tandem accelerator with vacuum insulation and lithium target. The proposed accelerator is conceived to deliver a proton beam around 10â¯mA at 2.3â¯MeV proton beam. To deliver a therapeutic beam for treatment of deep-seated tumors a typical Beam Shaping Assembly (BSA) based on the source specifications has been explored. In this article, an optimized BSA based on the 7Li(p,n)7Be neutron production reaction is proposed. To evaluate the performance of the designed beam in a phantom, the parameters and the dose profiles in tissues due to the irradiation have been considered. In the simulations, we considered a proton energy of 2.3â¯MeV, a current of 10â¯mA, and boron concentrations in tumor, healthy tissues and skin of 52.5â¯ppm, 15â¯ppm and 22.5â¯ppm, respectively. It is found that, for a maximum punctual healthy tissue dose seated to 11 RBE-Gy, a mean dose of 56.5 RBE Gy with a minimum of 52.2 RBE Gy can be delivered to a tumor in 40â¯min, where the therapeutic ratio is estimated to 5.38. All of these calculations were carried out using the Monte Carlo MCNP code.
Assuntos
Terapia por Captura de Nêutron de Boro/instrumentação , Neoplasias Encefálicas/radioterapia , Berílio/efeitos da radiação , Terapia por Captura de Nêutron de Boro/métodos , Terapia por Captura de Nêutron de Boro/estatística & dados numéricos , Simulação por Computador , Desenho de Equipamento , Glioblastoma/radioterapia , Humanos , Lítio/efeitos da radiação , Imagens de Fantasmas , Radioisótopos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por ComputadorRESUMO
A new semi-empirical formula for the calculation of the (n, He-3) cross section at 14.6MeV neutron energy is obtained. It is based on the evaporation model. The new formula with three parameters is found to give a better fit to the data than the previous comparable formulae.
