Pharmaceuticals for Binary Radiotherapy and Their Use for Treatment of Malignancies (A Review)

Abstract

Binary radiotherapy (BRT) is a type of radiation therapy that employs special drugs to direct ionizing radiation to a target. As a rule, the drug has no significant biological activity of its own. BRT causes damage due to interaction of secondary ionizing radiation with biological tissues. The special drug that accumulates selectively in a tumor contains chemical elements that absorb external ionizing radiation considerably more efficiently than the chemical elements in living tissues. The absorbed dose can increase from several percent up to five times as a result of the selective interaction of the external radiation with such drugs in tumors. Currently, two types of BRT exist, i.e., neutron-capture therapy (NCT), which uses neutron beams, and photo-capture therapy (PCT), which uses x-rays. NCT potentially has greater therapeutic efficacy than PCT. However, PCT equipment is less expensive and can be housed in existing clinical establishments. Numerous studies of BRT efficacy from many countries of the world indicate that this technology is potentially efficacious for treating malignancies. Introduction of BRT into clinical practice would enhance considerably the antitumor efficacy of radiotherapy and decrease the number of irradiations to a single one. The capability of BRT can be fully unleashed only by developing specialized drugs that satisfy the BRT requirements.