Why does the thyroid gland need special protection after a release of radioactive material?
The thyroid gland needs iodine to produce the hormones that regulate the body’s energy and metabolism. The thyroid absorbs available iodine from the bloodstream. The gland cannot distinguish between stable (regular) iodine and radioactive iodine, and will absorb whatever it can. In babies and children, the thyroid gland is one of the most radiation-sensitive parts of the body. Most nuclear explosions release radioactive iodine. When thyroid cells absorb too much radioactive iodine, it can cause thyroid cancer. Babies and young children are at highest risk. The risk is much lower for people over age 40. Thyroid cancer seems to be the only cancer whose incidence rises after a radioactive iodine release. KI protects only the thyroid, but it is the organ that most needs protecting.
