A brief review of radiation hormesis.
This paper reviews physical, experimental and epidemiological evidence for and against radiation hormesis and discusses implications with regards to radiation protection. The scientific community is still divided on the premise of radiation hormesis, with new literature published on a regular basis. The International Commission on Radiological Protection (ICRP) recommends the use of the Linear No Threshold (LNT) model, for planning radiation protection. This model states that the probability of induced cancer and hereditary effects increases with dose in a linear fashion. As a consequence, all radiation exposures must be justified and have a sufficient protection standard in place so that exposures are kept below certain dose limitations. The LNT model has sufficient evidence at high doses but has been extrapolated in a linear fashion to low dose regions with much less scientific evidence. Much experimentation has suggested discrepancies of this extrapolation at low doses. The hypothesis of radiation hormesis suggests low dose radiation is beneficial to the irradiated cell and organism. There is definite standing ground for the hormesis hypothesis both evolutionarily and biophysically, but experimental evidence is yet to change official policies on this matter. Application of the LNT model has important radiation protection and general human health ramifications, and thus it is important that the matter be resolved.
Jolly
D
D
Wellington Blood & Cancer Centre, Wellington Hospital, Private Bag 7902, Wellington South, New Zealand. david.jolly@ccdhb.org.nz
Meyer
J
J
D000222:Adaptation, Physiological / Q000528:radiation effects*; D000818:Animals; D002468:Cell Physiological Phenomena / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004781:Environmental Exposure; D006304:Health Status; D006801:Humans; D010809:Physical Fitness; D011839:Radiation, Ionizing