Radioactive Iodine Therapy for Thyroid Cancer

What is Radioactive Iodine Treatment and What Does It Do?

Stethoscope and Radioactive sign
Stethoscope and Radioactive sign. Getty Images/ULTRA.F/DigitalVision

Radioactive iodine therapy I-131, also known as radioiodine therapy, or (RAI), is circulated throughout your body in your bloodstream. It becomes concentrated in the thyroid gland, where the iodine destroys the gland’s cells. Radioactive iodine is mainly absorbed by the thyroid cells with little effect on other cells. It is used to treat follicular and papillary thyroid cancer and an overactive thyroid gland, a condition known as hyperthyroidism.

Radioactive iodine therapy may be given:

  • After a thyroidectomy, surgery to remove the thyroid gland, to destroy any cancer cells that remain
  • In the treatment of thyroid cancer that has spread
  • In the treatment of recurring thyroid cancer

You may need to have the treatment only once but it can be repeated every three months until there is no sign of thyroid cancer.

How to Prepare for Radioactive Iodine Therapy

Before undergoing treatment, you will be asked to begin a low-iodine diet at least two weeks before you have radioactive iodine treatment.

You will need to eliminate some of the following foods from your diet:

  • Iodized salt or sea salt
  • Cough medicine
  • Seafood and fish
  • Supplements containing iodine
  • Dairy products
  • Pink- colored foods with E127 additive

Too much iodine in your body will interfere with the results of the treatment. When a patient is given radioactive iodine, the iodine-starved thyroid cells absorb the RAI, destroying the cells.

The Radioactive Iodine Procedure

The procedure will take place in a hospital setting. You will be isolated from other patients for several days because the after-effects of the treatment cause you to become slightly radioactive. You will ingest the radioactive iodine in either liquid form or as a capsule.

You will need to refrain from eating so that your body can absorb the iodine. You will be able to eat and drink normally afterward. You will need to drink liquids to flush the radioactive iodine out of your system.

Once your radioactive levels have fallen, you will have a scan to determine where in your body the radioactivity has been absorbed.

After the Radioactive Iodine Procedure

Once your levels of radioactivity have fallen to a safe level you will be sent home with post-care instructions. You will need to avoid contact with small children, pregnant or breastfeeding women for a period of time. You will be told when you should begin taking your thyroid hormones and when to follow up with your doctor.

Side Effects of Radioactive Iodine Therapy

Depending on your age, overall health, and the amount of radioactive iodine you received, you may have one or more of the following short-term side effects:

  • Swelling and inflammation of the salivary glands
  • Dry mouth
  • Changes in taste and sense of smell

Possible long-term side effects may include:

Women should not attempt to become pregnant for up to a year after having RAI, or as directed by their physician. Women who are breastfeeding should not breastfeed until given approval from their physician. Travelers should note that for up to twelve weeks after treatment, they may set off radiation alarms at airports. To avoid a problem, you should get a note or certificate from the hospital regarding your treatment.

Those who have a total thyroidectomy as treatment for papillary thyroid cancer will require thyroid hormone replacement medication for the rest of their lives. Since the thyroid was removed during surgery, it can no longer produce the hormones needed to regulate metabolism and other critical functions. This thyroid hormone suppression therapy (THST) is available by pill and usually taken once a day. It also serves to suppress thyroid stimulating hormone in the body, which can reduce the risk of recurrence.

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