Positron Emission Tomography (PET)

Positron Emission Tomography (PET) is an invaluable imaging technology used most commonly in cancer management. PET makes it possible to diagnose and monitor changes in the body’s metabolism.

Positron Emission Tomography uses small amounts of a radioactive tracer (most commonly, a short-lived form of radioactive glucose called 18FDG), injected intravenously, to display normal and abnormal metabolic patterns in various organs throughout the body.

By combining PET images with CT (computerised Tomography) scanned at the same time by the same machine, the accuracy and sensitivity of the images are maximized.

A doctor’s referral and an appointment are required for a PET examination

You will need to bring:

• Your request form
• Completed questionnaires
• Any relevant previous imaging
• Your Medicare card and any concession cards
• Any medication you may need on the day

You will receive detailed printed instructions from Lake Imaging before the PET examination. We need to receive your referral form and know your weight before the appointment and you must fast for at least 6 hours before the examination, but you may be well hydrated with water only.

• If you are a diabetic and need to eat at regular intervals please notify Lake Imaging when making your appointment so that special instructions can be provided. You should also let us know of any other conditions which may affect the scan, including being pregnant, breastfeeding or caring for a small child.
• It is important to arrive on time for your PET examination, and give plenty of notice if you need to cancel or reschedule, as our isotope supply is costly, and has a very short shelf life.
• Most patients will have an additional, diagnostic CT scan scheduled immediately after the PET/CT scan. This is done immediately on the same scanner.
• The duration of both procedures, including preparation time is approximately 1.5 to 2.5 hours.

When you attend your appointment at Lake Imaging you will be asked to answer a few safety questions, remove any jewellery, watches etc, then change into an examination gown. If you would rather not get changed, wear clothing and underwear without any metal present to your appointment.

The technologist will prepare and inject the tracer into an arm vein. You will then rest alone for 45-60 minutes while the tracer distributes through the body. During this period, you will be asked to avoid frequent muscle activity and reading.

After the “uptake” time, the technologist will position you for the scan. The PET scanner is similar in appearance to a normal CT scanner; it takes around 15-25 minutes to complete the images. You are able to breathe normally, but must not move during this time.

If a diagnostic CT scan is scheduled, our radiographer will start this immediately after the PET scan. The CT procedure will be very similar to the PET scanning and may involve further injections of contrast material.

At Lake Imaging all PET/CT scans are performed by registered Medical Imaging Technologists, and a PET-credentialed radiologist or physician will review your relevant medical history, and other imaging, before reporting your PET/CT scans.

After the images are checked, we may ask you some further questions before leaving. There are generally no precautions to follow after your procedure.

Radiation from the injected isotope diminishes to a safe level by the end of the procedure, and you are free to resume normal activities immediately.

If you are caring for a small child, or breastfeeding, we may ask you to take some minor precautions. This will be explained to you by the staff at Lake Imaging.

If your results are required urgently, or you have an appointment straight after your scan with your referring doctor or health care provider, Lake Imaging will arrange to have your results available immediately. Otherwise your referring doctor or health care provider will receive your report within 48 hours of your examination.

PET/CT procedures are considered to be very safe and there have been no reported adverse reactions attributable to the use of 18F-FDG. Exposure to low doses of gamma radiation carries an extremely small theoretical radiation exposure risk. However, radiation exposure effects are cumulative in nature. With 18F-FDG the levels of radiation and theoretical risks are lower than typical CT scans. These factors will be taken into consideration by your referring doctor in the light of your medical history and be balanced against the benefits of performing the test. All radiation doses are reduced to a level as low as reasonably achievable. 

The contrast media administered for the diagnostic CT scan proceeding the PET scan is an iodine-based contrast. CT contrast is generally safe. Adverse reactions can occur ranging from minor to severe. However, severe reactions are extremely uncommon.

Please note: this service offering differs at our North Melbourne location. Any patients that require PET-CT at our North Melbourne clinic will be provided with alternative information and instructions pertaining to this service.