Iodotherapy: what is it for, effects on the body and risks

Radioactive iodine is an iodine-based medicine that emits radiation, used mainly for the treatment called Iodotherapy, indicated in certain cases of hyperthyroidism or thyroid cancer. In smaller doses, it can also be used to assess thyroid function in the Scintigraphy exam.

Iodine 131 is the most used in the treatment, however, iodine 123 is the best option for the examination, since it has lesser effects and duration in the body. To perform this type of procedure on the thyroid, a special preparation is necessary, which consists of avoiding foods and medicines that contain iodine about 2 weeks before. Here's how to do the iodine-free diet.

In addition, some precautions are necessary after using radioactive iodine, such as remaining isolated in a room for about 3 days, and avoiding contact with other people, especially children and pregnant women, until the levels of the medication decrease and there is no risk of contaminating other people with its effect.

What is it for

The use of radioactive iodine in medicine has 3 main indications:

1. Iodotherapy for Hyperthyroidism

Radioactive iodine can be used to treat hyperthyroidism, especially in Graves' disease, and is usually indicated when the patient has no improvement with the use of drugs, when he cannot use them due to allergies, when he has serious adverse reactions to medication or when more definitive treatment of the disease is needed, such as people who have heart disease, for example.

How it works: the treatment with radioactive iodine acts causing an intense inflammation in the thyroid cells, followed by fibrosis of its tissues, which is responsible for reducing the excess of hormones produced.

After treatment, the person will continue evaluations with the endocrinologist, who will monitor the functioning of the thyroid, if the treatment was effective or if there is a need to use medications. Check out more about the main ways to treat hyperthyroidism.

2. Iodine therapy for thyroid cancer

Treatment with radioactive iodine in thyroid cancer is indicated as a way of eliminating remnants of cancer cells after thyroid removal, decreasing the risk of cancer recurrence. In some cases, it can also be used to help eliminate metastases, and the symptoms produced by them.

How it works: radioactive iodine has an affinity for the thyroid, so it helps to find and eliminate cancer cells from this gland, the dose used being variable, calculated by the oncologist to be able to destroy these cells.

Learn more about the symptoms that can indicate thyroid cancer, how to diagnose and treat it.

3. Thyroid scintigraphy

It is an exam indicated by doctors to study the functioning of the thyroid, to investigate the diseases that may arise in this organ, especially when there is a suspicion of cancerous nodules or that are producing excess thyroid hormones.

How it works: to perform the exam, the person is asked to ingest a quantity of radioactive iodine (iodine 123 or iodine 131) with a straw, then images are generated for the device in 2 stages, one after 2 hours and the other after 24 hours. As the dose of radioactive iodine is low, the person can go out and perform their activities normally during this period.

Pregnant or breastfeeding women should not take this test. Find out more about when thyroid scintigraphy is indicated and how it is done.

Necessary care before iodotherapy

To carry out treatment with radioactive iodine, some precautions are necessary before the procedure, which include:

• Follow iodine-free diet, not consuming foods containing iodine in the 2 weeks prior to treatment or examination, which includes saltwater fish, seafood, seaweed, whiskey, processed breads, chocolates, canned, spicy or sardine-containing products, tuna or soy and derivatives, such as shoyo, tofu and soy milk;

See more in the following video:

• Do not use drugs that contain iodine or thyroid hormones in the days before the exam, as directed by the doctor; Avoid chemicals that contain iodine in the month prior to the exam, such as hair dye, nail polish, tanning oil or iodized alcohol, for example; Perform the fasting exam for at least 4 hours.

Care after iodotherapy

After taking the radioactive iodine tablet the person is left with high doses of radioactivity in the body, which passes through the skin, urine and feces, so some care is needed to avoid passing the radiation on to others:

• Stay in an isolation room for about 8 days after using radioactive iodine, as directed by the doctor. Generally, you can stay 2 to 3 days in the hospital and on other days you can be at home, but without contact with others, especially pregnant women and pets; Drinking plenty of water to produce more urine, which helps to eliminate radioactivity from the body; Consume citrus products, such as lemon water or candies, to stimulate the salivary glands to produce more saliva and fight dry mouth, and prevent them from suffering the accumulation of the medication. Always stay at a minimum distance of 1 meter from any person, not having sex or sleeping in the same bed, during the period recommended by the doctor; Wash all clothing used during that week separately, as well as sheets and towels; After urinating or evacuating always flush 3 times in a row, in addition to not sharing the bathroom with anyone else in the house.

Dishes and cutlery do not need to be washed separately, and there is no need for special food after taking radioactive iodine.

Possible side effects

Some of the side effects that treatment with radioactive iodine can cause include nausea, abdominal pain and swelling and pain in the salivary glands.

In the long run, the effect of radioactive iodine can cause hypothyroidism, requiring the use of medications to replace the lack of thyroid hormones. In addition, the action of radioactive iodine can also impair the functioning of other glands in the body, such as salivary and ocular glands, causing dry mouth or dry eyes, for example.