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Using radioiodine after rhTSH injections

Information about your treatment for thyroid cancer using radioiodine after rhTSH injections

What is radioiodine?

Radioiodine is a radioactive form of iodine.  Iodine is part of each of our diets and is needed for the thyroid gland to work normally. 

What does the thyroid gland do?

The thyroid gland controls the speed (metabolic rate) at which our body works. 

How does radioiodine work?

Like ordinary iodine, radioiodine is taken up by any thyroid cells left after your thyroid operation. The radioactive form of iodine is used to destroy any remaining thyroid cells.

How do you know if I need treatment?

The doctor will discuss different treatment options with you when you attend your out-patient appointment. You can ask any questions you have.  We will ask you to sign a consent form if you decide you want the treatment.

If I am advised I need radioiodine, where will my therapy be done?

If you are advised to have radioiodine therapy you will need to be admitted to the isotope cubicle. 

This is a single room with a bathroom on the Princess Margaret Ward.  This room has been specially adapted because of the high dose of radiation involved in the treatment. The treatment dose of radioiodine is usually given as a capsule.

What are the possible side effects from radioiodine?

Many patients do not experience any side effects with radioiodine.  However the following side effects can occur:

  • dry mouth
  • tender or swollen saliva glands
  • taste changes
  • sore throat
  • altered sensations around your thyroidectomy scar
  • swelling of your thyroid area if a significant amount of thyroid tissue is present
  • feeling sick (though this is uncommon) 

I have been told I will need to have two injections before my radioiodine, why is this?

We need to make sure the thyroid cells left in your body take up the radioiodine.  These 2 injections should make sure this happens. 

How are the injections given?

You will have 2 injections into your buttock muscle. They will be given 24 hours and 48 hours before your radioiodine capsule.  We will give you the injections on the ward or on the day unit. 

Are there any side effects from the injections?

Side effects are uncommon and generally mild.  Some people feel sick, have a headache or feel weak with aching muscles after their injections.  A few people have experienced a rash at the site of the injections. 

Do I carry on taking my thyroid hormone tablets whilst I am having treatment?

Yes.  

Can I eat and drink as normal before I have the radioiodine?

We encourage you to drink plenty of fluids, as this will help clear the radioactivity from your body more quickly.  The doctor will ask you to cut down on some foods that contain iodine for 7 days prior to your treatment.  We will give you a diet sheet to help.  Your doctor will discuss this with you in clinic. 

What happens when I arrive on the ward?

You will be seen by the ward doctor, a nurse and a physicist.  They will take some details from you, and then take you to the isotope cubicle.  The physicist will come to the cubicle and give you the radioiodine treatment capsule.

After an hour the physicist will come back to the cubicle to measure the level of radiation inside of you.  We will ask you to lie on the bed while a special monitor inside the cubicle does this.  This will be repeated each day.  The measurement does not hurt you. 

How long will I be in the hospital? 

Most people are in hospital for 2 - 4 days.  Whilst you are in the cubicle we will ask you to drink as much as possible.  This helps flush the remaining radioactivity out of your body.  Once the radioactivity level in your body is low enough you will be able to go home.

Please bring 3 – 4 days supply of any tablets you take.  Please do not bring in several weeks worth of medication as we will advise you to leave any bottles or packets that you have handled whilst in the cubicle. 

Does anything else need to be done before I go home?

Before you go home you will be taken to the Nuclear Medicine department for a scan.  We will ask you to shower and change into some clothing that you have not worn during your stay in the cubicle.

The scan is in 2 parts.  Each part takes about 30 minutes and looks at where the radioiodine has gone into your body.  You have to follow some instructions after leaving hospital, but we will explain these to you. 

What happens to the clothing I have worn whilst in the cubicle?

You need to wash it separately from everyone else’s when you go home or you can leave it in the cubicle for us to dispose of for you.

Can I have visitors whilst in the isolation cubicle?

You can have visitors but unfortunately children and pregnant or breast-feeding women cannot visit you whilst in the isolation cubicle.

Other visitors will not be allowed to come into your cubicle but you can speak to them on a phone in your room and another in the corridor.  You will be able to see each other through a special window whilst you are talking.  All visitors must speak to the ward staff before they visit.

What can I do to help?

  • Please take care not to splash the water outside the hand basin when washing, and particularly when brushing your teeth. 
  • Rinse your toothbrush thoroughly after each use.
  • Take care not to splash urine outside the toilet pan.
  • Flush the toilet twice after use.
  • If possible take a daily shower.

What do I need to bring in with me?

  • Washing items such as a towel, soap, toothbrush, toothpaste, shaving kit, hair brush or comb. Please bring small travel sized bottles as we suggest you leave all unused toiletries in the cubicle when you go home.
  • Several changes of clothing.
  • Magazines and paperback books.  Please do not bring in hardback or library books.
  • Soft drinks (small bottles 650mls or cans)

You should also bring enough money to pay for any newspapers or phone calls you may wish to make.  The money for any newspapers will be collected before you go into the cubicle.  

You can take money into the isotope cubicle for any phone calls you might wish to make.  There is a telephone in your room which will take incoming calls.  We will give you the extension number when you come in.  Your family and friends will be able to contact you via the main switchboard on 029 2061 5888 and ask for your extension number.

You can take a mobile phone into the isotope cubicle.  You will need to put it inside a plastic bag before using it in the cubicle.

What facilities does the isotope cubicle have?

As well as the usual furniture, the isotope cubicle has the following facilities:

  • A small fridge
  • TV / DVD
  • CD player / radio / clock
  • Hairdryer
  • Phone
  • En-suite toilet and shower

Please do not bring your own electrical items into the hospital if possible.  This is because we have to check them for safety.

Can I have the treatment if I am pregnant?

No.  We will ask if you are pregnant before we give you the radioiodine capsule.  If there is any doubt we will ask you to take a pregnancy test. 

You will need to avoid becoming pregnant for 6 months after your radioiodine treatment.

Can I have the treatment if I am breast-feeding?

No. You will need to stop breast-feeding before we can give you the treatment.

Can I father a child?

You will be advised to avoid fathering a child for 4 months after your treatment.

Is radioiodine dangerous to others?

We try and keep unnecessary radiation exposure to others to a minimum.  We will advise you on how to achieve this with your family and friends.  

Staff will not stay with you for any longer than is necessary to attend your needs.  We will wear gloves and other special clothing if we have to come into your room whilst you are in hospital. 

When will I know the results of the scan?

You will have a clinic appointment a few weeks after your treatment.  The doctor will discuss the scan that you had whilst you were an in-patient.

Will I have to have another treatment?

Some patients will need further treatment doses of radioactive iodine.   The doctor will discuss any need for more treatment with you in out-patients.

How will I know if I need further treatment?

8 -12 months after your treatment, your doctor may ask you visit one of the wards and the Nuclear Medicine department as an out-patient.  

On the selected Monday and Tuesday, you will need to go to the ward for your injections.  On the Wednesday visit, the physicist from the Nuclear Medicine department will give the radioiodine to you.  The amount of radioiodine we give you is much less than the amount you received for your treatment. We will explain everything to you and will also give you a letter explaining the things you need to do afterwards.  

We usually ask you to come back to the Nuclear Medicine department 2 days later.  At this visit you will have a scan and we will measure the amount of radioactivity in the area of the thyroid gland.  This simply involves you lying down on a bed for the scan and sitting on a chair for the neck measurement.  You will also have a blood test.  

When will I know the results of the scan and measurements?

The doctor will ring you when he or she has seen the results.  The doctor will then decide whether you need to have further radioiodine treatment as an in-patient.  If this is recommended, we will usually ask you to come into hospital within a few weeks.  

Further information

We hope you have found this leaflet helpful.  If you have any questions or want more information, please phone the Nuclear Medicine department on 029 2031 6237 or 029 2031 6238.


Velindre Cancer Centre 
Velindre Road, Whitchurch, Cardiff, CF14 2TL

This leaflet was written by health professionals.  The information contained in this leaflet is evidence based.  The leaflet has been approved by doctors, physicists and patients.  It is reviewed and updated every 2 years.  

Written December 2003
Reviewed November 2012