Skip to main content

Welcome to the Circle Health Group website. We've changed our name from BMI Healthcare. Just as before, we have thousands of specialists offering expert healthcare. Click here to find a specialist or a hospital near you.

Radioactive iodine treatment

Radioactive iodine treatment is a possible treatment for overactivity of the thyroid. We take a look at the treatment and what it involves.

Initially overactivity of the thyroid is treated by a course of tablets but when this fails to control the thyroid, Radioactive iodine treatment is a possible next option.

Radioactive iodine is taken by mouth as a capsule typically with a glass of water. The radioactivity in the capsule only lasts for a few days and for 90% of patients, one dose is sufficient to control the over activity. About 10% of patients may need a second dose but a third dose is rarely needed.

A second dose would be considered if a patient still needed to take carbimazole tablets to control their overactive gland six months after they had received their first dose of radioactive iodine.

The thyroid is very efficient at extracting iodine from the blood so the vast majority of the radioactive iodine is taken up by the thyroid gland. Very little of it goes elsewhere in the body. The radioactivity is therefore targeted at the thyroid gland.

Radioactive iodine takes at least a month to start to work and may take much longer. Some patients will be advised to re-start their carbimazole tablets one week after receiving their radioactive iodine, others do not. Your specialist with provide advice about this.

Thyroid blood tests are monitored every four to six weeks in clinic and your treatment will be adjusted according to the results.

Ultrasound imaging can be done as an outpatient and you will be able to go home immediately afterwards. This is a relatively quick, non-invasive and safe procedure with no known harmful effects.

Specialists offering Radioactive iodine treatment

Dr Kate Goodchild

Consultant Oncologist


Bishops Wood Hospital

View profile Enquire

Dr Theingi Aung

Consultant Physician and Endocrinologist

Circle Reading Hospital

View profile Enquire