Radioactive iodine treatment

Hyperthyroidism, or an overactive thyroid, is a condition where your thyroid produces excessive amounts of thyroid hormones, the hormones responsible for regulating your metabolism. Hyperthyroidism can cause symptoms such as nervousness, hyperactivity, difficulty sleeping and weight loss.

Other treatments for hyperthyroidism include medication to stop your thyroid gland from producing excessive hormones, and surgery to remove all or part of your thyroid gland (thyroidectomy). 
Your consultant may recommend radioactive iodine therapy to treat an overactive thyroid if:

• Medications haven’t worked or you can’t tolerate them 
• Thyroid surgery is too risky due to your health or other factors
• You have a decreased life expectancy

Radioactive iodine treatment usually destroys your thyroid gland so that it can no longer produce sufficient hormones. This means you will need to take medication to replace these hormones for the rest of your life.

Radioactive iodine therapy can be used to treat thyroid cancers such as papillary thyroid cancer (PTC) or follicular thyroid cancer. It works by targeting thyroid cancer cells which absorb the iodine even if they have spread to other parts of your body. Radioactive iodine therapy has very little effect on healthy cells in your body.

Your consultant may recommend radioactive iodine therapy if:

• You have any remaining thyroid tissue after thyroid surgery (radioiodine remnant ablation)
• Your thyroid cancer has spread to other parts of your body 
• Your thyroid cancer has come back after treatment, or you have a high risk of it coming back

Radioactive iodine treatment is a normally safe and effective procedure, but it isn’t suitable for everyone. You will not be able to have radioactive iodine therapy if you:

• Are pregnant or breastfeeding 
• Have diarrhoea or are vomiting 
• Have an eye condition called Graves’ ophthalmopathy (thyroid eye disease) 
• Have very high thyroid hormone levels (thyrotoxicosis)

At your first consultation, you will be seen by a consultant endocrinologist or oncologist, a doctor specialising in treating thyroid problems such as thyroid cancer or an overactive thyroid.

Your consultant will ask you about your symptoms, diagnosis and general health. They may ask to see the results of any previous tests or scans you have had, or they may arrange them on the day. They will ask about any previous treatments you have tried and how effective they were. They may perform a physical examination. 

Why is this first consultation so important?

At Circle Health Group, your first appointment is very important as it’s where you first meet your consultant, the doctor responsible for your care. Your consultant will spend time getting to know you, discuss your expectations for treatment and encourage you to ask any questions you may have. It is important to us that you are as well-informed and comfortable as possible during your treatment, so please discuss any questions or concerns with your consultant during your appointment.

At the end of your appointment, your consultant will decide if radioactive iodine treatment is a suitable treatment for you based on your diagnosis, general health and any treatments you have had previously. They will explain the treatment in full, including how to prepare for your treatment, any potential risks or complications and what to expect afterwards.

Before you have your radioactive iodine treatment, you’ll need to prepare a week or two in advance. This includes following a low-iodine diet and increasing your levels of certain thyroid hormones. Your healthcare team will give you clear instructions on how to prepare for your treatment. Please call the hospital if there’s anything you’re not sure about, or if you have any questions about how to prepare for your treatment.

Low-iodine diet

Having too much iodine in your body can make radioactive iodine treatment less effective, so you’ll need to start following a low-iodine diet a week or two before your treatment. Your healthcare team will give you instructions on what foods to limit or avoid and what you can eat freely.

Thyroid hormones

For your treatment to be effective, you need to have high levels of a hormone called thyroid stimulating hormone (TSH) in your blood. This is normally achieved by giving you an injection of synthetic TSH before your radioactive iodine treatment. You normally have two injections, 24 hours apart, starting two days before your treatment.

If you are unable to have the injections, your consultant may tell you to stop taking your thyroid-suppressing medication a few weeks before your treatment to allow your TSH levels to increase naturally.

Pregnancy and breastfeeding 

Having radioactive iodine treatment while you are pregnant or breastfeeding is dangerous and can harm your baby. If you are female and at an age where you can get pregnant, you’ll need to have a pregnancy test before starting treatment. If you are breastfeeding, you’ll need to stop at least six weeks before your radioactive iodine treatment.

Other tests

Your consultant may arrange some tests or scans before your radioactive iodine treatment. These may include:

• A blood test to check your thyroid levels
• A scan to check for any remaining cancer cells in your body

On the day of your radioactive iodine treatment, you’ll arrive at the hospital where you’ll be given your radioactive iodine as a drink, capsule or injection into a vein. You can eat and drink normally before and after your radioactive iodine treatment.

The iodine will be absorbed by your thyroid cells, which the radiation then destroys.

The treatment itself will feel very straightforward. Once you have been given the radioactive iodine, it will get to work in your body without you or your doctors and nurses needing to do anything further. 

There’s no recovery time needed after radioactive iodine treatment, but you will be radioactive for a few days after your treatment which could potentially harm other people. The radioactive iodine will gradually be eliminated from your body through your pee, poo, sweat and saliva. Drink plenty of fluids after your radioactive iodine treatment as this will help flush the radioactive iodine from your body. 
Your healthcare team will give you instructions on what precautions you need to take after your treatment.

These may include:

• Isolating yourself from others until your level of radioactivity is safe (this will be monitored regularly) 
• Washing your hands frequently
• Bathing or showering daily
• Sitting down when you pee and flushing the toilet twice after using the bathroom
• Avoiding sharing a bathroom with others where possible and not using public bathrooms 
• Not sharing clothes, towels, bed linen, cups, plates, or utensils and washing them separately 
• Avoiding public transport 
• Avoiding long car journeys with other people

How many nights will I need to stay in hospital?

In some cases, you can go home on the same day as your radioactive iodine treatment, but you’ll usually need to stay in hospital for a few days after treatment while you are radioactive to protect other people. During your stay, your level of radioactivity will be monitored regularly until they are safe.

Will I be able to drive home?

You can drive yourself home from the hospital once you are discharged.

How soon can I go back to work?

Once your radioactivity level is safe for the people around you, you can return to work as soon as you are ready.

How soon can I drive?

You can drive whenever you like after your radioactive iodine treatment. Avoid spending a long time in a vehicle with other people while you are radioactive.

When will I be back to normal?

Radioactive iodine treatment is a quick and simple procedure, and most people feel back to normal very soon after treatment. You are normally radioactive for around three days after treatment, but this depends on the dose of radiation you received and can be as long as two weeks.

It takes at least a month to see the results of radioactive iodine treatment. In some cases, your consultant may prescribe medication to control your overactive thyroid until your radioactive iodine treatment starts to work. You will have blood tests to monitor your levels of thyroid hormones every four to six weeks after your radioactive iodine treatment. Your consultant will adjust your treatment depending on the results.

Around 90% of patients having radioactive iodine therapy only need one treatment. If there is no improvement after six months, you may need a second treatment. A third treatment is rarely needed.

Radioactive iodine treatment is a generally safe procedure, but as with most medical treatments, side effects can occur in some people. Your consultant will explain all the possible side effects of radioactive iodine therapy to you before your treatment and encourage you to ask any questions you may have. Being as well-informed as possible about your treatment will help put your mind at rest and allow you to make an informed decision.

Possible side effects of radioactive iodine treatment may include:

• Dry mouth - this is usually temporary, but may become a long-term side effect 
• Neck swelling, tenderness or tightness 
• Flushing 
• Nausea - this is usually mild and gets better after a couple of days 
• Swelling and inflammation of your salivary glands 
• Gastritis - inflammation of your stomach lining 
• Changes to your sense of taste - this can occur days or weeks after treatment and normally improves within a couple of months 
• Dry eyes
• Hypothyroidism - your thyroid may produce no or insufficient amounts of thyroid hormones after radioactive iodine treatment, meaning you’ll need to take thyroid medication for the rest of your life

Pregnancy and fertility

After radioactive iodine treatment, you should not get pregnant for at least six months, and you may have a slightly higher risk of miscarriage for the first year after treatment. If you are male, you should not make someone pregnant for at least four months after your treatment. It’s important to use a reliable form of birth control during this time. Your consultant will provide further advice and information on fertility and pregnancy after radioactive iodine treatment. 

At Circle Health Group, we have the experience and expertise to ensure the best possible care and outcome for our patients. As a patient with Circle Health Group, you can expect the highest standards of care including:

• Flexible appointment times and locations that are convenient for you
• The freedom to choose which hospital and consultant suit your needs
• Personalised, consultant-led treatment plans tailored to your individual needs
• Comfortable and safe private facilities maintained by expert multidisciplinary teams
• Affordable, fixed-price packages with aftercare included
• Flexible payment options to help you spread the cost of your care

If you would like to see a consultant or learn more about radioactive iodine treatment, book your appointment online today or call a member of our team directly.

Radioactive iodine therapy - Cancer Research UK 

Radioactive Iodine (1-131) Therapy for Hyperthyroidism - RadiologyInfo.org 

Treatment of an overactive or enlarged thyroid gland with radioactive iodine - British Thyroid Foundation 

Radioactive Iodine (Radioiodine) Therapy for Thyroid Cancer - American Cancer Society