Radioiodine treatment for thyroid conditions

Radioiodine treatment usually cures an overactive thyroid (hypothyroidism) permanently. It does this by damaging your thyroid cells, reducing the amount of hormones it can produce.

If you have thyroid cancer, you will usually have surgery to remove it and this may then be followed by radioiodine treatment.  

Radiodine is the naturally occurring element iodine which has been modified to give off radiation. The amount of radiation you receive from radioiodine treatment can be compared to what you might receive from having an x-ray.    

Overactive thyroid (hypothyroidism)

Thyroid cancer 

You will take radioiodine as a either a liquid or in a capsule. Some people will need a second dose.

The amount of radioiodine you need will depend on:

• the size of your thyroid gland
• your age
• how severe your thyroid disease is
• whether you have thyroid eye disease and any other disease you have.

Your healthcare provider may ask you make changes to your medicines and diet before your treatment.

The iodine has no taste. Sometimes people notice in the week following treatment that they:

• feel a bit sick
• have some neck discomfort
• have a sore throat
• develop a dry mouth (because they make less saliva after radioiodine treatment).

Radioiodine is generally very safe. Very high doses can slightly increase your risk of developing a different cancer. Most people are given a relatively low dose, which is not thought to cause cancer.

Your doctor will talk to you about precautions you need to take with being around other people including your tamariki, partner, and at your workplace.

For about one week after the treatment, it is best that you sleep in a separate bed from your partner. 

Whether you should stay off work after your treatment depends on your job. If you work with children or pregnant women, you should take some time off work. If you work with adults, keeping them at 2 arms' length from you for a few days may be all you need to do. 

It is best that you go home by car after your treatment. If you have to take public transport, make sure that you only sit with adults. Move to another seat if a child or pregnant woman sits within 2 arms' length of you. 

Take care with your bodily fluids

Your thyroid takes up much of the radioiodine and you will pass the rest through your wee (urine) and poo. 

During the first 3 days after your radioiodine treatment, flush the toilet immediately. Then flush the toilet a second time and wipe up any spilled wee with a tissue and flush it away. Always wash your hands well afterwards. It is best for men to use the toilet sitting down.

There will also be radioactivity in other body fluids, including your

• saliva
• sweat
• mucus from your nose.

Use tissues to wipe your nose and make sure you put them in the rubbish — away from your kitchen and living areas. Do not leave tissues lying around.

Avoid cooking food for others and use your own crockery and cutlery for several days after your treatment.

Take care around your tamariki

There is no evidence that children are affected by their parent's treatment. But it is still recommended you keep their radiation exposure to a minimum.

The doctor who prescribes the radioiodine will tell you how long your thyroid will be radioactive after your treatment. During this time, usually 7 to 10 days, you should not have tamariki closer than 2 arms' length for more than a few minutes at a time.

But you do not need to stop essential contact such as cuddles, dressing or soothing. It is best to avoid kisses for 48 hours after the radioiodine.

Most people will develop low thyroid function after radioiodine treatment.

You will need to have a blood test to check your thyroid function at least once a year.