Accidents nucléaires et prophylaxie par l'iode 1re partie: Risques liés à l'irradiation de la glande thyroïde

In the frame of the emergency procedures in the case of an accident in a nuclear plant, this paper presents a survey of the information available on the risks related to the irradiation of the thyroid gland. Attention is focused on thyroid cancer resulting from an exposure to radioactive isotopes of iodine and especially of iodine-131. The consequences of the medical exposures as well as of the Hiroshima of Nagasaki irradiations are recalled first. Then the recently available information on the effects on the populations exposed after the Tchernobyl accident are analysed more in detail. Ten years after the accident, the most striking and the least questionable effect is a significant increase of the incidence of thyroid cancer in children, in the areas most exposed to the initial radioactive clouds. Young children are particularly vulnerable to this type of cancer which is of agressive nature and shows a short latency period. These observations justify an iodine prophylaxis for the populations living in the vicinity of nuclear plants. Special attention should be payd to the protection of young children.SCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Survey on national practices regarding iodine thyroid blocking in 2016-2017

Severe nuclear accidents may lead to a release of radioactivity, including radioactive iodine, into the environment. The thyroid gland in the human body needs natural or stable iodine to function properly and this iodine is normally absorbed in small quantities from food. Following a release of radioactive iodine from a nuclear or radiological accident, the body will absorb and accumulate the radioactive iodine in the thyroid gland. This increases the risk of thyroid cancer, especially in children. Since the thyroid gland cannot distinguish between radioactive and stable iodine, stable iodine can be taken to prevent the absorption of radioiodine by the thyroid in the event of a nuclear emergency. This is referred to as Iodine Thyroid Blocking (ITB). In 2017, the World Health Organization published revised guidelines entitled ‘Iodine Thyroid Blocking: guidelines for use in planning for and responding to radiological and nuclear emergencies’. The purpose of these guidelines is to support Member States in planning for and implementation of ITB before and during a radiation emergency. To enable the monitoring and measurement of the impact of a specific recommended intervention, a baseline should be established against which the impact will be measured over a certain period of time. With that in mind, a global WHO survey of national policies on ITB was carried out in 2016-2017. Here, an overview of some core findings of this survey is provided

Thyroid cancer incidence near nuclear sites in Belgium: An ecological study at small geographical level

In Belgium, variations in thyroid cancer incidence were observed around the major nuclear sites. The present ecological study investigates whether there is an excess incidence of thyroid cancer among people living in the vicinity of the four nuclear sites at the smallest Belgian geographical level. Rate ratios were obtained from a Bayesian hierarchical model for areas of varying sizes around the nuclear sites. Focused hypothesis tests and generalized additive models were performed to test the hypothesis of a gradient in thyroid cancer incidence with increasing levels of surrogate exposures. No evidence was found for more incident cases of thyroid cancer near the two nuclear power plants. Regarding the two industrial and research nuclear sites, no evidence for a higher incidence in the vicinity of Mol-Dessel was observed, whereas a slightly nonsignificant higher incidence was found in the close vicinity of Fleurus. In addition, significant gradients for thyroid cancer incidence were observed with the different types of surrogate exposure considered in the 20 km area around the site of Fleurus (decreasing distance, increasing wind direction frequency and increasing exposure to estimated hypothetical radioactive discharges of iodine-131). In the investigation at the smallest Belgian geographical level, variations in thyroid cancer incidence were found around the Belgian nuclear sites. Significant exposure-response relationships were also observed for the site of Fleurus. Further investigations into these findings could be useful to allow inferring causal relationships on the origin of variations in incidence and to provide information at the individual level.status: publishe

Thyroid Cancer Incidence around the Belgian Nuclear Sites, 2000–2014

&lt;p&gt;The present study investigates whether there is an excess incidence of thyroid cancer among people living in the vicinity of the nuclear sites in Belgium. Adjusted Rate Ratios were obtained from Poisson regressions for proximity areas of varying sizes. In addition, focused hypothesis tests and generalized additive models were performed to test the hypothesis of a gradient in thyroid cancer incidence with increasing levels of surrogate exposures. Residential proximity to the nuclear site, prevailing dominant winds frequency from the site, and simulated radioactive discharges were used as surrogate exposures. No excess incidence of thyroid cancer was observed around the nuclear power plants of Doel or Tihange. In contrast, increases in thyroid cancer incidence were found around the nuclear sites of Mol-Dessel and Fleurus; risk ratios were borderline not significant. For Mol-Dessel, there was evidence for a gradient in thyroid cancer incidence with increased proximity, prevailing winds, and simulated radioactive discharges. For Fleurus, a gradient was observed with increasing prevailing winds and, to a lesser extent, with increasing simulated radioactive discharges. This study strengthens earlier findings and suggests increased incidences in thyroid cancer around two of the four Belgian nuclear sites. Further analyses will be performed at a more detailed geographical level.&lt;/p&gt;</p

The first meeting of the who guideline development group for the revision of the WHO 1999 guidelines for iodine thyroid blocking

The meeting held in May 2014 in Würzburg, Germany, discussed the scope of the revision of the 1999 WHO guidelines for iodine thyroid blocking (ITB) by following the WHO handbook for guideline development. This article describes the process and methods of developing the revised, evidence-based WHO guidelines for ITB following nuclear and radiological accidents, the results of the kick-off meeting as well as further steps taken to complete the revision