PET stands for positron emission tomography. It is a nuclear medicine imaging test. A small amount of liquid radioactive material is injected into your body to help diagnose a variety of diseases, including cancers.
How does PET work?

The radioactive substance most commonly used in PET scanning is a sugar (like glucose) called FDG, which stands for “fluorodeoxyglucose”. It accumulates in your body wherever sugar is being metabolised at high rates and gives off energy which can be detected by the scanner. This detected information is then converted into images of your body showing which cells are using the most sugar. Cancer cells tend to use a lot of sugar and therefore show up well on PET images.

PET scanners are combined with a computed tomography (CT) scanner, called a PET-CT. CT images are created from multiple x-rays to build up an image of the structures insided your body. The PET or PET-CT scanner looks like a large box with a circular hole in the middle.

How to prepare


  • If you are claustrophobic or have required sedation for prior scans, please advise us and bring a relative or friend who can drive you home.
  • Do not bring small children with you.
  • Bring your medicare/DVA card.


  • If you are diabetic, you will need to call for specific instructions
  • Fast for 6 hours, water is allowed
  • Avoid strenuous exercise for 24 hours prior to scan
  • Wear warm clothing with no metal components


  • Eat and drink normally
  • Wear comfortable clothing with no metal components

Relevant Prior Imaging

  • Please bring prior imaging and advise staff of any prior PET scans
What to expect

While every PET scan is tailored to the specifics of the individual patient, there are a number of common factors.

When you come for your PET, you will be seen by the front desk staff who wil get all the paperwork done. Once this is completed, one of our technicians will take you into a room where they will ask you a few questions and then place a small needle (a canula) into a vein in your hand or arm. 


The canula is used to check your blood sugar level before we start and then to give the FDG. Once you are given the FDG, you will be asked to sit or lie quietly for 30 - 40 minutes while the material is absorbed. As FDG is basically glucose, it is extremely unlikely you will have any reaction at all. After this time, you will be taken through to the camera room and placed on the camera bed. The scanner will move over you a few times as the data is obtained. We typically scan from the top of head to the mid thighs. The scan itself will take 30 minutes. After this is done, you will be free to go home.

Variations on this include occasionally needing to come back for later images (mainly brain tumour patients) or longer imaging time if we need to scan right down to your toes. For some patients, you will be asked to drink a different contrast material.


This is different from FDG. We will place you on the camera after canula insertion and then take pictures of your pelvis straight after injection for 20 minutes. Once this is done we will scan for an additional 30 minutes from head to thighs. All together, you will be on the camera for almost 1 hour, after which you can go home.