Stable iodine prophylaxis is a protective measure of administration of stable iodine to block uptake and reduce accumulation of of radioactive iodine released in nuclear reactor accidents, in thyroid. The administration is done before, or promptly after, intake of radioactive iodine released in nuclear reactor accidents. Intake of radioactive iodine by inhalation begins when the radioactive cloud arrives at a location and continues during the passage of the cloud. Action to implement stable iodine prophylaxis, and thereby reduce the dose to the thyroid, will be required promptly. The decision will most probably have to be made in a situation when reliable data for calculating the potential dose to the thyroid are not available.
Stable iodine could also be used as prophylaxis against ingested radioactive iodine from contaminated food. However, in such situations, the iodine prophylaxis will be required for a longer period of time, leading to a need for repeated doses. In such situations, food controls would be easier to implement and more effective in the long term in reducing the collective dose than stable iodine prophylaxis.
