How is radioiodine therapy for the thyroid gland performed ?

Radioiodine therapy of the thyroid gland has been practiced for half a century. The method is based on the properties of the thyroid gland to absorb iodine entering the body. After entering the thyroid gland, the radioactive isotope of iodine destroys its cells. Thus, the excessive production of hormones is blocked, which led to the disease. Such therapy requires preparation and hygiene requirements during rehabilitation. However, radioactive iodine treatment has advantages over surgery.

What is radioactive iodine

Radioactive iodine began to be used for the treatment of the thyroid gland more than 60 years ago. Iodine- 131 (I-131) is an artificially created radioactive isotope of iodine. Its half-life is 8 days. As a result of the decay, beta and gamma radiation is released, propagating from the source at a distance of half to two millimeters.

An excess amount of hormonal substances secreted by the thyroid gland leads to cardiovascular problems, weight loss, nervous system disorders, and sexual dysfunction. To stop the production of excess hormone, iodine-131 treatment is performed. This method is also used when neoplasms appear in the thyroid gland. 

The method is based on the ability of the thyroid gland to absorb all the iodine in the body. Moreover, its variety does not matter. After getting into the thyroid gland, I-131 destroys its cells and even cancerous (atypical) cells outside the thyroid gland.  

The radioactive type of iodine dissolves in water and can be airborne, so treatment with this substance requires strict precautions.

Who is radioiodine therapy indicated for ?

Treatment of thyrotoxicosis with radioactive iodine is carried out because of the need to suppress the excessive production of a hormone that poisons the body.

Radioiodine therapy is indicated:

  • with thyrotoxicosis due to Basedow’s disease; 
  • with oncological diseases of the thyroid gland;
  • after removal of the thyroid gland to get rid of residues and metastases of oncological neoplasms of the thyroid gland (ablation);  
  • with autonomous adenomas;
  • with unsatisfactory results of previous treatment with hormones.

Radioiodine therapy is the most effective method when compared with surgery and hormonal treatment.

Cons of surgical excision of the thyroid gland:

  • the inevitability of anesthesia;
  • long period of suture healing;
  • the risk of damaging the vocal cords;
  • no guarantee of complete removal of pathogenic cells.

Hormone therapy also has many unpredictable side effects.

How is the thyroid gland treated with radioactive iodine?

When all the tests have been passed and the thyroid gland studies have been completed, the doctor together with the patient determines the date of the therapeutic procedure. Its effectiveness is about 90% the first time. When repeated, the figure reaches 100%.

The entire therapeutic period is divided into three stages: preparatory, the procedure itself and the time of rehabilitation. It is important to know in advance what they are, so that no requirement or question of the doctor is taken by surprise. Understanding and cooperation on the part of the patient increases the chances of a successful procedure.


An iodine-free diet before radioiodine therapy is considered the most important exercise. The beginning of the period is discussed with the doctor, but comes no later than two weeks before the procedure. The task of the thyroid gland at this time is to “starve” for iodine so that when I-131 enters the body, the thyroid gland gets the maximum dose. After all, if there is enough iodine in it, the medicinal dose simply will not be absorbed. Then all efforts will be wasted.

Before receiving radioiodine therapy, women should have a pregnancy test.

Exclude from the diet:

  • seafood, especially seaweed;
  • soybeans and other legumes;
  • foods colored red;
  • iodized salt;
  • any medications with iodine. 

The concentration of thyroid-stimulating hormone must be increased so that the cells of the thyroid gland absorb iodine as much as possible. Its amount should exceed the norm.


Treatment of the thyroid gland with radioactive iodine takes place in a hospital. You don’t need to take a lot of things with you, because you still won’t be able to use them. Before the procedure, the medical staff will provide disposable clothing. The patient deposits his belongings until discharge.

The doctor suggests taking a capsule with iodine 131 and drinking plenty of water. Some clinics use an iodine solution. Since the introduction of a radioactive isotope is unsafe for healthy people, medical personnel are not present in the room, and the patient now needs isolation.

After a few hours, the following symptoms may manifest themselves:

  • dizzy;
  • vomiting even to vomiting;
  • places of accumulation of radioactive iodine hurt and swell;
  • dryness in the mouth;
  • dries eyes;
  • the perception of taste changes.

Sour candies, drinks (you can take them) help to avoid dry mouth.


The first days after the procedure, the rules of behavior and personal hygiene are prescribed. They must be observed so that iodine leaves the body as soon as possible, and also so as not to harm others.


  • to drink a lot of water;
  • take a shower 1-2 times a day;
  • regularly change underwear and clothing in contact with the body;
  • men are instructed to urinate only in a sitting position; 
  • after visiting the toilet, flush the water 2 times;
  • not to come into close contact with relatives and other people, especially the prohibition applies to pregnant women and children.

A few days later, the doctor determines the scheme of further drug treatment. By scanning gamma radiation, the location of the metastases is revealed. 

The main goal of treatment – destruction of the abnormal thyroid tissue – is achieved only a few months after the procedure.

What drugs can and cannot be taken before and during radioiodine therapy

Levothyroxine , a synthetic thyroid hormone, is canceled a month before the procedure . Withdrawal of this drug may be accompanied by such side effects as depression, constipation, weight gain, dry skin. This is considered the norm.

Multivitamins , cough medicines, and food supplements containing iodine should be put aside.

You need to stop taking:

  • thyreostatics ( Tyrozol , Mercazolil );
  • any medication containing iodine (Amiodarone);
  • ordinary iodine for external use.

To whom therapy is contraindicated

Radioiodine therapy is prohibited for pregnant women due to the possibility of abnormalities during fetal growth.

When planning a pregnancy, the doctor will advise you to postpone conception for six months or a year. Moreover, the ban applies to representatives of both sexes. If the pregnancy has already occurred, the specialist will suggest alternative therapies.

I-131 treatment is incompatible with:

  • lactation;
  • stomach and duodenal ulcers;
  • renal and hepatic impairment.

The procedure also cannot be performed on children under 18 years of age.

Is a person receiving radioactive iodine dangerous for others?

The half-life of I-131 is 8 days. This is the period during which the thyroid gland is irradiated. The substance leaving the body does not change its qualities. For a patient, such irradiation of the thyroid gland is a targeted therapeutic effect. But the transfer of an isotope that emits radiation to others can contribute to negative consequences.

Therefore, during the rehabilitation period, it is not allowed to have close contact with other people: hug, kiss, even sleep on the same bed. Sick leave is given for a month. For employees of child care facilities, sick leave can be extended to two.

Consequences of treatment with radioactive iodine in the thyroid gland

The use of iodine-131 has certain negative consequences. Their development is possible, but not necessary:

  • swelling of the small intestine;
  • autoimmune ophthalmopathy ;
  • hypothyroidism requiring lifelong hormonal therapy;
  • in men, sperm activity decreases, temporary infertility is possible (up to two years);
  • in women, menstrual irregularities are possible. It is necessary to avoid pregnancy for one year, to refuse breastfeeding.

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