The thyroid protection in case of nuclear accident by an iodine prophylaxis

The first part of the thesis describes the thyroid functional activity and the place of iodine in organisms, iodine is linked to the thyroid functioning. The second part of the thesis is interested in the ionizing radiation effect in general then on the thyroid. The external irradiation has been essentially studied from the data of the Hiroshima and Nagasaki explosions. The internal contamination of thyroid is known by the use of 131iodine for medical or diagnostic uses. A mixed contamination is described with the example of the nuclear test in Marshall Islands. Follows a chapter devoted to the thyroid cancers, the most serious thyroid radioinduced pathology. The third part concerns the place of iodine in the nuclear power plants. The functioning of a nuclear power plant is described as well as its radioactive emission in normal operation and in accidental situation. The sanitary impact of a radioactive iodine emission is detailed from a bibliographic synthesis coming from the studies on the development of thyroid cancers appeared after the Chernobylsk disaster. The ingestion of steady iodine constitutes an preventive measure efficient against the arising of these cancers. Its efficiency and innocuousness are discussed. Then a last part summarizes the administrative measures taken in France so that the population can have at her disposal iodine tablets before and in case of accidents. (N.C.)