Moderated 252Cf neutron energy spectra in brain tissue and calculated boron neutron capture dose

While there is significant clinical experience using both low- and high-dose 252Cf brachytherapy, combination therapy using 10B for neutron capture therapy-enhanced 252Cf brachytherapy has not been performed. Monte Carlo calculations were performed in a brain phantom (ICRU 44 brain tissue) to evaluate the dose enhancement predicted for a range of 10B concentrations over a range of distances from a clinical 252Cf source. These results were compared to experimental measurements and calculations published in the literature. For 10B concentrations 50 μg/g, the 10B neutron capture dose enhancement was small in comparison to the 252Cf fast neutron dose.