Boron, gadolinium, and lithium neutron capture therapy: A multi-scale simulation by Geant۴ and Geant۴-DNA toolkits

Boron neutron capture therapy (BNCT) is an emerging targeted radiation therapy leveraging nuclear capture reactions to maximize tumor cell destruction with minimal damage to healthy tissues. Given to clinical possible concentrations, attentions have recently been paid to ۱۰B alternatives. This study presents a dosimetric comparison between BNCT, gadolinium neutron capture therapy (GdNCT) and lithium neutron capture therapy (LiNCT) using the Geant۴ Monte Carlo toolkit, evaluating dose distributions and therapeutic gain across varying concentrations (۱-۵۰ ppm) of ۱۰B, ۱۵۷Gd, and ۶Li in a Snyder head phantom. Furthermore, Geant۴-DNA simulations were employed to quantify DNA damage and predict cell survival via the Two-Lesion Kinetic model. The results demonstrate that both BNCT and LiNCT, as alpha-emitters, achieve superior tumor dose enhancement and normal tissue sparing compared to GdNCT. At ۵۰ ppm, BNCT and LiNCT produced a ۶۴-۸۵% dose enhancement, outperforming GdNCT by more than ۲۰-fold. Micro-scale analysis revealed that ۱۰B and ۶Li induce a high proportion of complex, lethal DNA double-strand breaks, leading to a steep, concentration-dependent decrease in cell survival. While ۶Li is identified as a potent and promising alternative alpha-emitter, ۱۰B maintained a marginally higher biological effectiveness. This study not only confirms BNCT's clinical superiority but also provides a rigorous framework for evaluating novel neutron-capture agents, underscoring the critical importance of radiation quality over neutron cross-section alone.

کلیدواژه ها:

Neutron capture therapy ، BNCT ، GdNCT ، Dose enhancement ، Monte Carlo simulation ، GEANT۴ ، Geant۴-DNA