A simple approximation for the evaluation of the photon isoeffective dose in Boron Neutron Capture Therapy based on dose-independent weighting factors

Abstract

The current methodology for determining the biological effect of Boron Neutron Capture Therapy (BNCT) has recently been questioned, and a more accurate framework based in the photon isoeffective dose has been proposed. In this work we derive a first order approximation to this quantity than can be easily evaluated even from limited data, as is the current situation in the radiobiology of BNCT. This procedure removes the main drawbacks of the current method and it is based on new weighting factors that, as a difference with the previously used, are true constants (dose independent). In addition to this, we apply the formalism to allow the comparison to a fractionated conventional radiotherapy treatment, for which there is a lot of knowledge from clinical practice. As an application, the photon isoeffective dose of a BNCT treatment for a brain tumor is estimated. An excel sheet used for these calculations is also provided as supplementary material and can be used also with user-provided input data for the estimation of the photon isoeffective dose for comparison with conventional radiotherapy, both to single and fractionated treatments.