RESUMO
The beam shaping assembly design has been investigated in order to improve the epithermal neutron beam for accelerator-based boron neutron capture therapy in intensity and quality, and dosimetric evaluation for the beams has been performed using both mathematical and voxel head phantoms with MCNP runs. The neutron source was assumed to be produced from a conventional 2.5 MeV proton accelerator with a thick (7)Li target. The results indicate that it is possible to enhance epithermal neutron flux remarkably as well as to embody a good spectrum shaping to epithermal neutrons only with the proper combination of moderator and reflector. It is also found that a larger number of thermal neutrons can reach deeply into the brain and, therefore, can reduce considerably the treatment time for brain tumours. Consequently, the epithermal neutron beams designed in this study can treat more effectively deep-seated brain tumours.
Assuntos
Terapia por Captura de Nêutron de Boro/instrumentação , Neoplasias Encefálicas/radioterapia , Nêutrons/uso terapêutico , Aceleradores de Partículas , Proteção Radiológica/instrumentação , Radiometria/instrumentação , Planejamento da Radioterapia Assistida por Computador/instrumentação , Carga Corporal (Radioterapia) , Terapia por Captura de Nêutron de Boro/métodos , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento/instrumentação , Análise de Falha de Equipamento/métodos , Raios gama/uso terapêutico , Cabeça/fisiologia , Cabeça/efeitos da radiação , Humanos , Reatores Nucleares , Imagens de Fantasmas , Radiometria/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Eficiência Biológica Relativa , Reprodutibilidade dos Testes , Medição de Risco/métodos , Sensibilidade e EspecificidadeRESUMO
A BNCT (Boron Neutron Capture Therapy) treatment planning system (BTPS) was developed for BNCT study and treatment planning. Three kinds of CT images, VHP, PINNACLE and DICOM images, were employed to make voxel phantoms for BNCT patient treatment using the BTPS. The thermal neutron, fast neutron, gamma and boron doses are calculated and background, tissue, and tumour doses for idealised standard reactor neutron field (ISRNF) neutron beam were calculated by using BTPS and MCNP code. It was noted that the total computing times needed for BNCT analysis could be greatly reduced since the BTPS system provides a dose analysis tool and a lengthy MCNP input in a short time. It is, thus, expected that the BTPS can significantly contribute the BNCT study for the treatment of patients.