1 Faculty of medicine and pharmacy of Rabat
2 Faculty of medicine and pharmacy of Casablanca
3 Faculty of medicine and pharmacy of Fez
Ionizing radiation is part of the human environment has many sources; some of them natural (earth, cosmos...) and athers artificials (medical, industrial and military). They generate effects that include a wide range of reactions that are different from each other in their dose-effect relation. These effects are often subdivided into two main categories: deterministic and stochastic.
The carcinogenicity of ionizing radiation, which described early at the beginning of the 20th century, has been since then widely documented. other wise, the hereditary effects of irradiation have never been demonstrated in humans. Many studies have shown the existence of a linear relation between radiation exposure and tumors excess from an exposure to 200 mSv.
The problem of the risks exposure to low doses of ionizing radiation is a concern of the scientific community. No health effects have been observed in the majority of epidemiological studies, and the absence of this effects do not rule out the risk existence.
Research on low doses shows that the nature of the biological responses of low doses of radiation differs from those of by high doses of radiation. They also show the diversity of relation ship betwin dose response of the mechanism and the genetic predisposition in individual susceptibility to low doses of radiation.
The current regulatory texts on low-dose and low-dose rate exposures to ionizing radiation make the implicit assumption of the persistence of a residual risk whatever the level of exposure, with tables for the repair of occupational diseases ranging from simple anemia to bone sarcoma.
An immense amount of research remains to be done, particularly in radiobiology and in the modeling of radon-induced carcinogenesis, as well as the follow-up of cohorts of exposed subjects, even after the cessation of occupational exposure, to better understand and quantify the effect of low and very low doses of ionizing radiation.
The objective of our work is to explain the scientific foundations on which the regulatory texts are based and to draw up the current state of knowledge on processes involved in the biological effects of ionizing radiation.