Boron neutron capture therapy

Boron neutron capture therapy relies on a boron drug that accumulates in tumour cells: 10B captures thermal neutrons and fissions into alpha and lithium particles with a range of about 10 micrometres, so the damage is confined to the cell that took up the boron. It is approved in Japan (2020) for recurrent head and neck cancer using accelerator-based neutron sources (Sumitomo) and borofalan (10B). Trials extend to glioma and melanoma. The selectivity is cellular-level in principle, but in practice the boron delivery agent limits tumour selectivity, and very few facilities exist. The simple version is that a boron drug marks the tumour cells and a neutron beam then makes only those cells explode from inside.