What is radiation hormesis?
Radiation hormesis is a hypothesis that suggests that exposure to low levels of radiation expxosure is actually beneficial to biological tissues by stimulating their innate protective mechanisms  . In this context, low levels of exposure are defined as those similar to background radiation exposure. The protective mechanisms include: detoxification of reactive oxygen species, repair of DNA damage, induction of apoptosis, increased immune-mediated cell death, induction of terminal differentiation, and increased expression of “stress response” genes. The hypothesis is that exposure to low levels of ionizing radiation stimulates the housekeeping functions of the immune system and persists for hours to days after the exposure. There continues to be a great deal of controversy surrounding this hypothesis, as it is contrary to the LNT hypothesis that was previously introduced. At present, there is no conclusive evidence for either hypothesis.