Neutron therapy
Neutron therapy is a form of particle therapy using neutrons as the energy-carrying particle. The therapy has shown promise for some malignancies but there have also been problems with accurate dose distributions and late complications. Some of these problems historically were thought to be - at least partially - due to crude facilities. There has been renewed interest in non-proton particle therapies in view of the advances made in the accurate targeting of external beam radiotherapeutic techniques, e.g. IMRT.
Neutron therapy remains a very specialized niche modality which is currently only available at a few centers worldwide due to very high associated resource costs.