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Thyroid Uptake and Scan for Thyroid Cancer

A Thyroid Uptake checks how well your child’s thyroid gland is working.   A Thyroid Scan looks at the size, shape and position of your child’s thyroid gland.


Your child will be asked to stop all food and drink 2 hours before coming in for the test on Day 1 and continue to fast for 1 more hour after leaving. Your child’s doctor will ask for bloodwork a few days before the test.

Your child will be asked to change their diet and stop certain medications, cough syrups and vitamins before the test.  Please refer to the following guidelines:

  • If your child is on thyroid medications they will need to be stopped before the test. Your child’s doctor will let you know when to stop certain medications. This can be from 1 to 6 weeks before the test so it is important to check with your child’s doctor.
  • Stop multivitamins, 4 weeks before the test
  • Stop cough medicines 48 hours before the test
  • Your child will be asked to go on a low iodine diet 1 week before the test. Including:
    • Do not eat fish, shellfish or other sea-based foods
    • Do not eat foods with a lot of iodized salt or sea salt

No other test (for example, CT, MRI or Xray) where your child received contrast though IV or to drink for 6 weeks before the appointment

What to expect

The scan is done in 2 parts over 2 days.  Each part will take 30 to 60 minutes to complete.  One parent or guardian may stay with the child at all times during the test.  Siblings are not allowed in the room during the test. 

Part 1

Your child will need to drink a small amount medicine that contains some Iodine combined with a small amount of radiation.  This medicine will mix with the blood and accumulate in the thyroid gland.  Your child will be asked to not have anything to eat or drink for 1 hour after the medicine is given.  It will take about 24 hours for the medicine to go to the thyroid gland.  You and your child can leave the department after the medicine is given.  You will be given a time to return the next day.

Part 2

When your child returns to the department, 2 sets of pictures will be taken using special cameras. The 1st set of pictures will be done with your child sitting very still in a chair.  A machine will come really close to your child’s neck and look at the amount of iodine that has been gathered by your child’s thyroid.

For the 2nd set of pictures, your child will be asked to lie down on a narrow bed and a seat belt will go across their stomach.  This will allow us to take pictures of their thyroid to see where the iodine has gathered.  The pictures will be taken with a special camera and will take about 30 minutes to complete.  Your child should not feel any discomfort during the scan and can choose to be distracted (for example, listen to music). 

Post test

Once you leave the department on Day 1, your child will be asked to have nothing to eat or drink for 1 more hour.  After this, it is important to give your child extra fluids for the rest of the day to keep them hydrated and help the medicine leave the body quicker.  

The scan results are given by a doctor specialized in Nuclear Medicine and not by the technologist doing the test.  A report is sent to your doctor’s office, usually within 2-3 business days. 

Please call the Nuclear Medicine Department at 416-813-6065 if you have any questions about the procedure or if you need to change the appointment.

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