Radioiodine Therapy for Thyroid Cancer

In most cases, patients diagnosed with thyroid cancer will have a thyroidectomy (surgery to remove the thyroid gland), followed by radioiodine treatment. Even when the whole thyroid gland is removed during surgery, it is possible for small remnants of thyroid tissue to be left behind.  In some cases it is also possible that some malignant thyroid tissue may be found elsewhere within the body. The radioiodine is given as a capsule, and accumulates naturally in both normal thyroid tissue and thyroid cancer, in the same way that iodine in food is taken up by the thyroid. The radiation released by the radioiodine destroys these thyroid cells wherever they are in the body.  As the radiation is short-range, damage to surrounding tissue is kept to a minimum. This treatment has been around for over 50 years and is considered both effective and safe.

In approximately one third of patients, not all of the remnant thyroid tissue will be destroyed with one treatment and they may need to come back for a higher amount of radioiodine.

Radioiodine therapies for thyroid cancer are carried out on an inpatient basis on Onslow Ward at the Royal Surrey County Hospital. Stays are usually between one and four nights, depending upon the amount of radioiodine given and how quickly it clears from the body. The treatment is carried out by a Medical Physicist, who also gives radiation protection advice at discharge. An oncology doctor will also be involved in the therapy. The therapy itself is administered orally as a capsule. In order to ensure that the therapy is as effective as it can be, patients must reduce the amount of iodine in their diet for two weeks before the therapy.

The therapy will take place in a single en suite room and during the stay the patient must remain in the room at all times. Visitors are limited to one at a time and no pregnant women or children are allowed to visit the patients during this time.  No visitors are allowed in the first 24 hours after radioiodine treatment. The room is set up as below.

Radiation protection advice is given on discharge by a Medical Physicist.  The advice involves restricting close contact with other people for a period of time. The exact length of time depends on how quickly the iodine is cleared from the body, which is measured by the Medical Physicist during treatment.

After your therapy, you will have a scan in the Nuclear Medicine Department that will look at where the radioiodine has been taken up in your body. This information will help doctors decide whether you are likely to need further treatments.

More detailed information on this therapy and the low iodine diet can be found in the Patient Information Leaflet:

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