External Beam Fast Neutron Therapy: Russian Clinical Experience and Prospects for Further Development.

Fast neutron cancer therapy, having been initially in comparable demand to proton radiation therapy from the 1970s until the end of the 20th century, is now used on only a very few facilities for limited clinical applications. In Russia, fast neutron modalities were extensively investigated and used in various clinical contexts. The opportunities for such development were provided by extensive research infrastructure in the field of particle physics and its availability for clinical studies. Three research centers located in Obninsk, Chelyabinsk, and Tomsk (Fig. 1) proneutrons around the world.2