Development of a model to predict BNCT therapeutic effects in consideration of intracellular boron concentration and DNA repair during neutron irradiation

Matsuya, Yusuke  ; Omura, Motoko*; Fukunaga, Hisanori*

Boron neutron capture therapy (BNCT) is a treatment method enabling selectively eradicating tumors by -particles and Li ions generated through the nuclear reaction between neutrons and B within tumor cells. While the accelerator-based neutron source has been developed, the intracellular B concentration dynamically changes after intravenous injection of the boron into patients, and the neutron-delivery time is relatively long for 30 minutes or more. However, the quantitative analysis for investigating the impacts of DNA repair during irradiation on curative effects is insufficient. In this study, we developed a mathematical model for predicting the therapeutic effects that considers the change in intracellular B concentration and DNA repair, and performed detailed analysis. The model developed in this study considers the following two factors: one is microdosimetric quantities (physical characteristics) that depends on B concentration, and the other is DNA repair dynamics (biological process) during irradiation. The model estimation results exhibits that the importance of DNA repair during irradiation is reduced in the case of BNCT with a higher dose at sub-cellular scale than photons. It was also suggested that the DNA repair effects on tumor control cannot be ignored even in the case of BNCT. In the future, further accumulation of radiobiological data is desired for improving models.