Radioactive Iodine Therapy (OP) Information Letter

Download the Information Sheet

What is an overactive Thyroid?

The thyroid gland is responsible for making hormones which regulate the body’s metabolism and releasing these hormones into the bloodstream. Metabolism is the process of converting food and oxygen into energy and this process can be affected if the thyroid gland is not working properly. Certain conditions cause the thyroid gland to make and release more hormones than the body needs; these conditions can be referred to as ‘Overactive Thyroid’ or ‘Hyperthyroidism’.

What is Radioactive Iodine Therapy (RAI)?

Iodine in the body is primarily absorbed by the cells of the thyroid gland. 131Iodine (a radioactive form of iodine) can be given to treat an overactive thyroid. It is absorbed by the thyroid gland (just like normal iodine) which will then cause some of the thyroid tissue to be eliminated by radiation. This process is painless and should reduce thyroid function so that it will no longer be overactive. The procedure involves swallowing a capsule which is similar to other capsule or tablet medicines. Please inform Nuclear Medicine if you have trouble swallowing capsules or tablets.

What preparation is required?

You must not have anything to eat or drink on the morning of the treatment; this means you must fast from midnight but you can have small sips of water. You must also continue to fast for 2 hours after you swallow the capsule.

Some medications can interfere with the treatment; your doctor should have a discussion with you about which medications you should stop taking.

You must not have radioactive iodine therapy if you are pregnant or breastfeeding; if you are a woman of child bearing age (12-60) a blood test on the morning of the treatment is required to confirm that you are not pregnant. Following this therapy females should not become pregnant for at least 12 months and males should not father children for at least 6 months.

Do I require a scan?

Sometimes you will be required to undergo a Thyroid Uptake Scan prior to your treatment which helps check how well the thyroid gland will respond to the treatment. You will be informed if this scan is required.

What are the risks of Radioactive Iodine Therapy?

The major risks and complications of this treatment are outlined below but you should discuss your particular case with your doctor. Your doctor will consider the benefits of the treatment against these risks. Exposure to radiation may slightly increase the risk of developing cancer.

Common risks and complications include:

  • The treatment may cause you to have a permanent underactive thyroid. An underactive thyroid will require thyroid hormone replacement (tablets) for the rest of your life.
  • The treatment may not successfully treat your overactive thyroid which may require another dose of radioactive iodine.

Less common risks and complications include:

  • Mild neck soreness and swelling for a few days after the treatment - which usually responds to pain medications.
  • Grave’s disease only – Slightly greater chance of developing thyroid eye disease which will cause swelling of the eyes.

What happens when I go home?

You may need to stop or start taking medication at specific times; please consult with your doctor to make sure you have a medication plan.

Due to the risk of your thyroid becoming underactive you should follow-up with your specialist after your treatment.

If you are unwell in any way after your therapy you should contact your Specialist (the doctor who referred you for this treatment) or your GP.

When you go home after taking the capsule, your body will still contain an amount of radiation.

Precautions to follow:

  • Keep a distance of 2 metres between yourself and any children or pregnant women.
  • Do not participate in any intimate activities.
  • Sleep in a separate bed away from others, and do not share linen.
  • Wash your clothes and bed linen separate from other people’s washing.
  • Do not share cutlery/crockery and wash it separately to others.
  • Do not share your toothbrush. • Do not travel in a car or public transport with other people for more than two hours per day.
  • Flush the toilet twice and sit down while urinating for 5 days.

It is also important that:

  • Women should not become pregnant for 6-12 months after therapy.
  • Men should not father children for at least 3-6 months after therapy.
  • The above two points should be discussed with your referring doctor especially if you plan on having children.

It is important to bring any previous test results and your Medicare card with you

Please feel free to call us on 6244 4345 if you have any questions or to reschedule

Canberra Hospital Map