Radiation Countermeasures: An Emerging Scientific Field Based Upon Concerns for Nuclear Reactor Accidents and Radiation Terrorism

Radiation countermeasures are a primary focus of research not only in Clinical Medicine to prevent acute and chronic side effects of radiotherapy, but also now for planning space missions that will expose astronauts to continuous levels of irradiation for months or years. Radiation countermeasures development has emerged from the concern about nuclear reactor accidents and to manage the acute effects of detonation of a fission or fusion bomb. Countermeasures approach all of the steps in radiation damage and repair including DNA strand breaks, mitochondria response to DNA strand breaks in the nucleus, mitochondrial-mediated initiation of death pathways including apoptosis, and also nonmitochondrial mechanisms of cell death. Prominent is the understanding of the communication of cell death to other cells in distant areas through the production of inflammatory cytokines and neurological response modifiers. Each step generates a focus for discovering and developing small molecule and therapeutic cytokines as countermeasures. The side effects of radiation countermeasures are a major safety concern and have led to a second area of research.