What effect does radioactive iodine therapy have on the thyroid?

What effect does radioactive iodine therapy have on the thyroid?

• A. Increases thyroid hormone production
• B. Has no effect on thyroid function
• C. Destroys the thyroid gland
• D. Replaces the thyroid gland with artificial tissue

Answer: (C)

Radioactive iodine therapy works by delivering iodine directly to thyroid cells, which take it up as they normally would. The radiation from iodine-131 damages and destroys thyroid follicular cells, reducing the gland’s ability to produce thyroid hormones. Over time this ablation lowers thyroid function and often leads to hypothyroidism, for which lifelong thyroid hormone replacement may be needed. It does not increase hormone production, it is not without effect, and it does not replace the gland with artificial tissue. The destruction happens gradually as the tissue is damaged by the radiation.

Radioactive iodine therapy works by delivering iodine directly to thyroid cells, which take it up as they normally would. The radiation from iodine-131 damages and destroys thyroid follicular cells, reducing the gland’s ability to produce thyroid hormones. Over time this ablation lowers thyroid function and often leads to hypothyroidism, for which lifelong thyroid hormone replacement may be needed. It does not increase hormone production, it is not without effect, and it does not replace the gland with artificial tissue. The destruction happens gradually as the tissue is damaged by the radiation.