RESUMO
Gamma dose and thermal neutron fluence in a phantom exposed to an epithermal neutron beam for boron neutron capture therapy (BNCT) can be measured by means of a single thermoluminescence dosemeter (TLD-700). The method exploits the shape of the glow curve (GC) and requires the gamma-calibration GC (to obtain gamma dose) and the thermal-neutron-calibration GC (to obtain neutron fluence). The method is applicable for BNCT dosimetry in case of epithermal neutron beams from a reactor because, in most irradiation configurations, thermal neutrons give a not negligible contribution to the TLD-700 GC. The thermal neutron calibration is not simple, because of the impossibility of having thermal neutron fields without gamma contamination, but a calibration method is here proposed, strictly bound to the method itself of dose separation.
Assuntos
Terapia por Captura de Nêutron de Boro/métodos , Raios gama , Neoplasias/radioterapia , Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/métodos , Calibragem , Fluoretos , Humanos , Compostos de Lítio , Nêutrons , Imagens de Fantasmas , Fótons , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Reprodutibilidade dos TestesRESUMO
Suitable dosimeter methods have been proposed and tested, to measure the different dose contributions in small phantoms exposed to epithermal/thermal neutron beams designed for BNCT. One method is based on Fricke-gel dosimeter in small tubes of 2.8mm of external diameter, that allow determining profiles of gamma dose and of boron dose. The other method is based on the use of TLD-700 chips, from whose answer the contribution of thermal neutrons is subtracted by means of appropriate parameters of the glow curve.