Radioactive contamination
Some organs concentrate certain elements and hence radionuclide variants of those elements. This action may lead to much lower removal rates. For instance, the thyroid gland takes up a large percentage of any iodine that enters the body. Large quantities of inhaled or ingested radioactive iodine may impair or destroy the thyroid, while other tissues are affected to a lesser extent. Radioactive iodine-131 is a common fission product; it was a major component of the radioactivity released from the Chernobyl disaster, leading to nine fatal cases of pediatric thyroid cancer and hypothyroidism. On the other hand, radioactive iodine is used in the diagnosis and treatment of many diseases of the thyroid precisely because of the thyroid's selective uptake of iodine.
Iodine (medical use)
Iodine is used to treat and prevent iodine deficiency and as an antiseptic. For iodine deficiency it can be given by mouth or injection into a muscle. As an antiseptic it may be used on wounds that are wet or to disinfect the skin before surgery.
Common side effects when applied to the skin include irritation and discoloration. When taken by mouth or injection side effects may include allergic reactions, goitre, and thyroid dysfunction. Use during pregnancy is recommended in regions where deficiency is common, otherwise it is not recommended. Iodine is an essential trace element.
In 1811, Bernard Courtois isolated iodine from seaweed while in 1820 Jean-Francois Coindet linked iodine intake to goiter size. It initially came into use as a disinfectant and for goiter. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Table salt with iodine, known as iodized salt, is available in more than 110 countries. In areas with low dietary iodine one dose of iodine a year at 0.32 USD per dose may be recommended.