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Radioactive iodine therapy

Radioactive iodine therapy

Available at Icon Cancer Centre in Bali International Hospital

What is radioactive iodine therapy?

Radioactive iodine (RAI) therapy is a type of internal radiation treatment used to treat certain thyroid conditions, including thyroid cancer.

Iodine is a natural substance that your thyroid gland uses to make hormones. Radioactive iodine (RAI) is a specially prepared form of iodine that allows doctors to target and treat thyroid cells.

Because thyroid cells naturally absorb iodine, radioactive iodine can target thyroid tissue, including some thyroid cancer cells, precisely.

Radioactive iodine therapy may be recommended:

After thyroid surgery, to destroy any remaining thyroid cells
To treat thyroid cancer that has spread to lymph nodes or other parts of the body

It’s a well-established and effective treatment used worldwide.

How it works

Radioactive iodine is usually given as a capsule that you swallow. Once absorbed into your bloodstream, it travels to thyroid cells in the body. These cells take up the iodine, and the radiation then works from inside the cell to damage and destroy it. This helps reduce or eliminate remaining thyroid tissue or cancer cells.

You will be temporarily radioactive after receiving the capsule. This means you will need to stay in hospital for a short period so your radiation levels can be safely monitored. At Icon Cancer Centre, this typically involves:

Admission to hospital for approximately two to three days (exact length of stay depends on your dose and how quickly radiation levels fall)
Staying in a private room designed to limit radiation exposure to others
Daily monitoring of radiation levels by our Nuclear Medicine team

You will also be asked to follow several safety precautions such as:

Flush the toilet 2-3 times after use; sit while urinating to avoid spills
Drink 3-4 litres of fluid/day and frequent voiding.
Start sour candies/lemon 24 hours after administration of RAI
Receive your food and drinks in disposable containers

Before treatment, you may be asked to:

Stop thyroid hormone tablets (or receive alternative injections to raise thyroid-stimulating hormone levels)
Follow a low iodine diet for around two weeks before treatment and avoid certain medications – we’ll provide you with low iodine diet instructions
No water soluble iodinated IV contrast has been administered in the last 4-8 weeks
Fast for at least 4-6 hours before taking the iodine capsule and 1-2 hours after

Your Nuclear Medicine team will provide detailed instructions in the lead up to your treatment.

Side effects

Most people tolerate radioactive iodine therapy well. However, some temporary side effects can occur.

These may include:

Nausea
Neck discomfort or swelling
Dry mouth
Changes in taste
Mild difficulty swallowing

These effects are usually temporary. Let your care team know if you feel unwell at any time.

Because radioactive iodine can affect saliva glands, drinking fluids and following specific mouth care advice may help reduce discomfort.

Frequently asked questions

Most people stay in hospital for two to three days. The exact length of stay depends on the dose of radioactive iodine you receive and how quickly the radiation levels in your body decrease.
You can go home once your radiation levels have dropped to a safe range. Your care team will check these levels daily and let you know when it’s safe to leave the hospital.
After taking the capsule, your body will temporarily give off small amounts of radiation. Staying in a private room helps protect others from unnecessary exposure. The room is specially prepared for this purpose, and our team will explain any safety measures that are in place.
Visitors are usually not permitted during your stay. Your care team will provide clear guidance about what applies in your situation.
You may still have a small amount of radiation in your body when you go home. This gradually decreases over time.
Before you leave hospital, you will receive written instructions outlining temporary safety precautions. These will include guidance about:
- Sleeping arrangements
- Time spent in close contact with others
- Food preparation and shared utensils
- Laundry
- Work and social activities
These precautions are usually needed for a short period only. Your team will explain how long they apply to you.
Most people tolerate radioactive iodine therapy well. However, some temporary side effects can occur, including:
- Nausea
- Neck discomfort or swelling
- Dry mouth
- Changes in taste
- Mild difficulty swallowing
Less commonly, people may notice dry eyes or temporary changes in saliva production. Let your care team know if you feel unwell at any time.
Yes. Preparation helps make the treatment more effective. You may need to:
- Stop thyroid hormone tablets (or receive alternative injections to raise thyroid-stimulating hormone levels)
- Follow a low iodine diet for around two weeks before treatment and avoid certain medications – we will provide you with low iodine diet instructions
- No water soluble iodinated IV contrast has been administered in the last 4-8 weeks
- Fast for at least 8 hours before taking the iodine capsule and 1-2 hours after
Your Nuclear Medicine team will provide personalised instructions well in advance of your treatment.
No. Radioactive iodine is not safe during pregnancy or breastfeeding.
If you’re able to become pregnant, you’ll need a pregnancy test before treatment. Your care team will also discuss contraception and how long to avoid pregnancy after treatment.
If you’re breastfeeding, you’ll need to stop before treatment begins.
Many people require thyroid hormone replacement after thyroid surgery and radioactive iodine therapy. If this applies to you, your doctor will prescribe replacement tablets and monitor your hormone levels with blood tests.
These tablets replace the hormones your thyroid would normally produce.
Yes. A follow-up Nuclear Medicine scan is arranged before you are discharged from the hospital. This helps your doctors assess how the radioactive iodine has been absorbed and compare it with your pre-treatment imaging.
Your results will be reviewed and discussed with you by your care team.
This depends on your treatment dose and the safety precautions required after discharge.
Your care team will advise you about when it’s safe to return to work, exercise, travel, or resume close contact with others.