Radioactive iodine is often chosen as a first line treatment for adults with hyperthyroidism. Sometimes we use it as treatment for relapses of hyperthyroidism. Either way, most of my patients have second thoughts. When you use RAI for hyperthyroidism, it accumulates in the thyroid gland and starts destroying the thyroid cells that over produce thyroid hormones. So eventually these cells die off and the thyroid hormone levels fall in the blood. Very few tissues other than thyroid absorb significant part of iodine and so it does not affect other cells.

It is given as pill and done as outpatient. 90 % of patients will require only one dose of radioactive iodine. Eventually patients taking radioactive iodine become hypothyroid (low levels of thyroid hormones). They will then require thyroxine replacement. It is recommended that women have a pregnancy test before using radioactive iodine. Radioactive iodine does not cause infertility but it is recommended that women refrain from conceiving for 1 year after the procedure.

Since these radioactive substances may be excreted by the body, some precautions may be recommended by your doctor. This may include

  • Sleep alone for 5 nights after RAI.
  • Close contact with children or pregnant women (hugging or kissing; for example), should be avoided for 7 days
  • Drink plenty of water
  • Stay at least 2 meter from others for the first 3 days after treatment.
  • For 3 days, do not share items (utensils, bedding, towels, and personal items) with anyone else. Do your laundry and dish washing separately.
  • Wipe the toilet seat after each use. Wash your hands often, and shower daily. Flush the toilet after every use.

Check your thyroid function 2 months after the dose and meet your doctor for expert advice. Radioactive iodine does not cause cancer.