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Precautions Following Radioactive Iodine Therapy

Because your body retains and then gives off radiation after treatment with radioactive iodine (also called radioiodine), you will need to follow certain precautions to ensure safety to yourself and others. You will be given detailed instructions at Virginia Mason about what you should do for several days following your treatment, such as sleeping in a separate bed, limiting time in public places, and avoiding travel by airplane or mass transportation.

These precautions also pertain if a family member or friend is driving you to your treatment. You will be advised to maintain a distance of three feet from others for several days following radioiodine therapy. You also will need to wait several days before traveling on a prolonged automobile trip with other people.

Over time, the amount of radiation in your body will diminish and eventually will go away. Depending on the dose of treatment you initially received, you may need to stay in the hospital for several days to allow the level of radiation in your body to fall before returning home. Once you are at home, you may need to curtail certain activities such as having contact with children and pregnant women, and going back to work right away, so that radiation levels can fall to safer levels.

In general, there are three basic principles to keep in mind to reduce radiation exposure to others:


The greater the distance you are from others, the less radiation they will receive. You will be advised to sleep alone for the first few days after your treatment. During this period, you should avoid kissing or sexual intercourse. Also avoid prolonged physical contact with others, particularly children and pregnant women.

If you have a baby, be sure to get instructions from your doctor. You can probably do all the things necessary to care for your baby, except breast feeding (see below), but it is preferable not to have the baby too close, such as sitting in your lap, for more than a short time during the first two days after treatment.


Radiation exposure to others depends on how long you remain in close contact with them. You will be advised to minimize the time spent in close contact with others. Drink plenty of liquids, such as water or juices, to help you urinate frequently. This should help to flush out the radioiodine, thus lowering the amount in your body.


Good hygiene lessens the possibility of contaminating others. Guidelines are to wash your hands with soap and plenty of water each time you go to the toilet. Keep the toilet very clean. Also, flush the toilet two or three times after each use. Rinse the bathroom sink and tub thoroughly after using them to reduce the chance of exposing others to the radioisotope in your saliva and sweat. Use separate eating utensils for the first few days and wash them separately to reduce the chance of contaminating other family members with radioiodine in your saliva.

Pregnant women & nursing mothers

If you are pregnant, or think you are, tell your doctor because radioiodine should not be given during pregnancy. If you are planning to become pregnant, ask your doctor how long you must wait after the treatment.

If you have been breast feeding your baby, you must stop because radioiodine is secreted in breast milk.

If you have been breast feeding, radiation exposure to breast tissue will be significantly reduced by discontinuing breast feeding two (2) weeks prior to radioiodine therapy.