4. Concentration of radioactive iodine in the thyroid
A thyroid blocking agent protects the user from concentration of radioactive iodine in the thyroid.
A thyroid blocking agent is a pill, typically containing potassium-iodide. The thyroid blocking agent contains non-radioactive iodine which if taken before or immediately after exposure to radioactive iodine, saturates the thyroid with non-radioactive iodine.