PET-CT scan

The information below is about a procedure at the Queensland Children's Hospital and may not apply to other hospitals and health facilities.

A PET-CT scan takes images of organs and tissues inside the body and puts them together to creates 3D images.

Why does my child need a PET-CT scan?

Your child may need a PET-CT scan if a health professional needs to:

  • see how different organs in the body are functioning
  • detect or manage infections, conditions or diseases
  • assess the effectiveness of treatment.

Your health professional will let you know the reason for your child’s scan.

What to expect

The appointment could take up to 3 hours.

Before the PET-CT scan

Before you come to the hospital, we’ll call let you know what type of preparation you need to do for the scan. We’ll also answer any questions you have.

Before the scan, your child will need to have a tracer fluid injected. To do this we’ll need to insert a cannula, this is like having a blood test. Before inserting the cannula, we may apply a numbing cream or cool sense to the area.

If your child already has a central line or port, we’ll use that to inject the tracer instead.

Once they have the tracer, they’ll need to sit still and relax for about one hour.

During the PET-CT scan

PET-CT scans take about 30 minutes.

The PET-CT scanner looks like a big doughnut. For the scan, your child will need to lie on a table that moves through the middle of the doughnut and try to stay still. We may use foam cushions or soft straps to help them stay still.

If they have trouble staying still, they may need to have a general anaesthetic or sedation. Find out more about general anaesthesia.

After the PET-CT scan

After the scan, we’ll monitor your child for a short period and give them something to drink. We’ll also remove their cannula.

A nuclear physician will prepare a report about your child’s PET-CT scan and send it to the health professional who referred them. The health professional should let you know when they get them.

Preparing for the PET-CT scan

The most important things to remember are:

  • your child shouldn’t eat or drink anything for 4 to 6 hours before their scan, it can affect the quality of the scan
  • make sure your child doesn’t wear clothing with metal clips or snaps and removes all jewellery
  • make sure your child wears something warm and comfortable.

How much radiation exposure is in a nuclear medicine study?

Your child will receive a very small amount of radiation, which comes from a radiotracer and, if needed, a CT scan. Nuclear medicine tests have been safely used on children for over 40 years. The low radiation doses and the way these tests work make them a safe and effective option for diagnosing children’s conditions.

Specialists in nuclear medicine make sure your child gets the smallest radiation dose needed for an accurate diagnosis, following a principle called ALARA (As Low As Reasonably Achievable). The amount of radiotracer used depends on your child’s weight, the reason for the test, and the area being scanned. The radiotracers used break down quickly into non-radioactive forms, and part of them leaves the body naturally through urine.

Some parents may be concerned about the small amount of radiation their child might give off after the procedure. However, this exposure is usually much smaller than the natural radiation we all receive each year. In most cases, you can stay with your child during the procedure if you choose.

For more information

Watch our PET-CT scan video to find out more about what it’s like to have a PET-CT scan.

Watch
3:07
Having a PET-CT scan at Queensland Children's Hospital.

Hi, I'm Claudia, I'm going to show you what happens when you have a PET-CT scan.

A PET-CT scan is short for Positron Emission Tomography and Computed Tomography, which is simply a machine, with lots of special cameras, which take detailed images of the inside of your body. Some say it looks like a big doughnut.

There are two things you need to do to prepare for your PET-CT scan.

Don't eat or drink anything for four to six hours before the scan.

Don't wear any clothes with metal on them, such as buttons.

You'll also have to take off any metal jewellery or watches, this is because metal will make the pictures look bad.

When you arrive for your scan, the first thing to do is to check in at the front desk, so the team know you're here.

If you're a patient in the ward, your nurse will take you to the medical imaging department.

The medical imaging nurse will then take you to the uptake room, to get ready for your scan.

The nurse will ask you your name, date of birth and your address.

They will also check that you haven't had anything to eat or drink in the past four to six hours.

Make sure you are not wearing anything metal, as it will make the pictures look bad. You will change into a hospital gown, or pyjamas, if necessary.

A doctor will also come by to have a chat, to make sure you're ready for the scan.

For your scan, a thin tube called a canular will be placed in your arm. If you already have a central line or port, they will use this.

A special substance called sparkle juice is then injected through the canular, central line or port, to help the doctors see the inside of your body clearly.

You have to wait for around an hour after having the sparkle juice before you can have your scan. Your mum or dad can wait with you in the uptake room while you watch a movie. They just have to stay behind a special protective shield.

- Hey Mum!

- Hi honey!

The last thing you need to do before your scan is go to the toilet to empty your bladder,

or have a wee. Now you're ready for your PET-CT scan.

The person who takes the picture is called a tech.

- This is Troy.

- Hi everyone!

For the first part of the scan, you will slide in and out of the doughnut while the tech takes some planning pictures.

Next, you will slide into the scanner again, so pictures of your body can be taken. This is a CT scan part.

For the last part, you will move further into the machine for more pictures. This is the PET scan part.

It will take around twenty minutes, and it's very important that you lie still at all times, so that the tech can take the best pictures.

You will be able to watch a movie on the roof while you wait, but remember to stay really still.

After the scan, your pictures will be sent to the doctor, so they can look at them and write a report.

You will be given something to eat, and maybe even a sweet treat for doing well. The canular will also be taken out if you needed one. The whole process might take some time, but once you're in the doughnut, it's actually fun.

That's it for now, good luck.

Last updated: January 2025

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