Information for Consumers - Positron Emission Tomography (PET)

This article tells you about a positron emission tomography (PET) scan, the benefits and the risks, what happens before, during and after having a PET scan.

What is a positron emission tomography (PET) scan?

A PET scan uses a special camera and a computer to take pictures of the organs in your body. Most PET scans also use a low radiation dose CT scan so the areas of the body are more accurately identified.

You will be given a radioactive liquid (isotope) into a vein in your hand, arm, or foot.

The scanner has a round opening in the centre and a flat bed for you to lie on. While you are lying on the bed, it will slowly move you into the opening where the pictures are taken. The movement is controlled by the staff.

A PET scan may be used to show:

  • Cancer and what stage it is at
  • Diseases of the heart or brain

Benefits of a PET scan

  • Shows all the organs of the body in one image
  • May show changes before CT or MRI scans
  • Can show if you have cancer and how far it has spread
  • Can be used to look at the response of your cancer treatment
  • Generally painless

Risks of PET scan

Your doctor knows the risks of having a PET scan. Your doctor will consider the risks before recommending you to have a PET scan. Possible risks are:

  • Not recommended for pregnant or breastfeeding women
  • Very small chance you could develop cancer in the long term from the radiation
  • Infection, bleeding or bruising at the site of an intravenous injection


  • Bring your referral letter or request form and all x-rays taken in the last 2 years with you
  • Leave the x-rays with the staff, as the doctor may need to look at them. These will be returned to you before you leave or you will be told when these are ready to be picked up
  • Leave all jewellery and valuables at home
  • You may be asked not to eat or drink for 6 to 8 hours before the PET scan.
  • If you are diabetic, you will be given special instructions

Just before the PET scan

  • You may be given a gown to wear
  • You may be asked to remove any metal objects
  • You may request or be asked to take a tablet to help you relax (sedative)

Important to tell your doctor before the PET scan

  • If you are or may be pregnant.
  • If you are breastfeeding
  • If you have any allergies
  • If you are diabetic
  • If you have eaten anything

What happens during a PET scan?

Staff will put a needle into a vein in your hand or arm ready for the injection. Staff will prick your finger with a small needle and use a special machine to measure the amount of sugar in your blood.

Radioactive liquid

The staff will inject a small amount of radioactive liquid into a vein in your hand or arm. You will then wait around 60 minutes while the liquid moves through your body. Staff will then ask you to go to the toilet to empty your bladder before you have your PET scan.

PET scan

You will be asked to lie on a bed. The staff will set up the camera and leave the room while the pictures are taken. They can see, hear and speak to you at all times. You will be able to speak to them at all times. They will tell you what is happening and when to hold still. If you get stiff, need to move or are feeling closed in (claustrophobic), tell the staff.

The camera may pass over your body while it is taking the pictures. A PET scan takes 1 to 2 hours including time taken to get ready. The scan itself takes about 20 minutes.

When the scanning is finished you will be asked to wait while the staff check the pictures.


You have the right to refuse an examination and may do so if you wish. You may be asked to fill in a consent form.

When will I get the results?

The amount of time it takes for you to get your results will differ depending on where you get your scans done. The imaging specialist will look at the pictures and write a report. The pictures may be on films or on a CD.

Ask whether you should wait to take the pictures and report with you, or whether they will be sent to your doctor.

Your doctor will need to discuss the report with you. You will need to make an appointment to do this.

After the PET scan

You will be able to go soon after the PET scan has finished and can continue with normal activities.

  • Staff will need to take out the needle if it is still in your hand, arm or foot
  • Staff will give you any special instructions
  • The radioactive liquid will disappear from your body with only a very small amount remaining after 2 to 4 hours
  • Drink plenty of fluid to help get rid of the radioactive liquid

If you had a sedative

  • You must not drive a car or take public transport and must have someone with you for 24 hours afterwards
  • You must not operate machinery for the rest of the day


For an Australian patient in a Public Hospital in Western Australia

  • Public patient - no cost to you unless advised otherwise
  • Private patient - costs can be claimed through Medicare and your health insurance provider

For a patient in a Private Hospital or Private Imaging Site in Western Australia or a patient outside Western Australia

  • sk your doctor or the staff where you are having your test done what the cost will be

Further information

For more detailed information please access PET scan from InsideRadiology at:

This is a resource produced especially for consumers by the Royal Australian and New Zealand College of Radiologists:

A guide to gathering information that you may need for making informed decisions is published by the Consumers' Health Council of Australia at:

If you would look at other relevant article, please access the following:

Or for other relevant information access the Diagnostic Imaging Pathways website at:

Or if you have questions or require any further information please contact your doctor or speak to the staff where you are going to have your procedure.

Consumer participation

This information has been reviewed by representatives from the following groups:

  • Aboriginal people
  • People with disabilities
  • Seniors
  • CALD (Culturally and Linguistically Diverse)
  • The Health Consumers' Council


All feedback, comments and suggestions regarding consumer information at Diagnostic Imaging Pathways are welcome. Please click on Contact Us


This article is intended as general information only. The Diagnostic Imaging Pathways team and Radiology Across Borders will not accept any liability arising from its use. The information is kept as up-to-date and accurate as possible. Please be warned that it is always subject to change.


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Date reviewed: July 2017

Date of next review: July 2019