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Positron Emission Tomography

What is PET?

Positron Emission Tomography (PET) is a specific nuclear medicine imaging test in which a small amount of radioactive tracer is injected into the body. It is used to investigate a number of conditions, including a broad range of cancers, infection, some inflammatory disorders, neurological conditions and heart disease. Radiopharmaceuticals used in PET have very short half-lives, so the radiation leaves the body quickly.

To enable accurate localisation of where the uptake is seen within the body on the PET images, the PET scanner incorporates a Computed Tomography (CT) scanner into the same system. The CT scanner uses x-rays to create a detailed image of the anatomy inside the body over which the PET images are displayed. The PET/CT scanner looks very similar to a CT scanner, a large ring or donut shape where the patient lays on the bed as it moves through the centre of the ring.

Before the start of the test, please inform the staff if you are pregnant or breast feeding, or markedly claustrophobic.

18F-FDG PET

18F-FluoroDeoxyGlucose is the radiopharmaceutical most commonly used in PET scanning. It is a glucose analogue which is injected into the bloodstream and accumulates in areas of the body where there is increased metabolism. The radiopharmaceutical gives off gamma rays which are detected by the PET scanner, creating detailed images showing how tissue and organs are working.

This radiopharmaceutical is commonly used for cancer imaging, however it is also useful for imaging inflammatory or infective processes, and brain metabolism.

Due to the glucose nature of the radiopharmaceutical, you will need to fast for 4-6 hours prior to attending for this scan. If you are diabetic, please advise the department prior to attending as we will need to discuss your diabetic medication with you regarding any need to change your dosage on the day of the scan.

It is preferred for you to attend well-hydrated for the appointment, plain water is allowed during the fasting period and your bladder can be emptied as frequently as needed.

Occasionally other medications may be given as part of the PET scan, e.g. diuretic or insulin. Any possible side effects will be discussed with you at the time. If light sedation is required due to severe claustrophobia, you will need someone to accompany you home and will not be able to drive yourself.

An 18F-FDG PET scan will take approximately 2-3 hours for the entire procedure, with the scan lasting from 10-40 minutes, depending on the reason you are having the scan.

Gallium-68 PSMA

This radiopharmaceutical is used for staging or restaging prostate cancer.

There is no need to fast for this scan; however it is preferred for you to be well-hydrated.

Occasionally other medications may be given as part of the PET scan, e.g. diuretic. Any possible side effects will be discussed with you at the time. If sedation is required due to severe claustrophobia, you will need someone to accompany you home and will not be able to drive yourself.

A PSMA PET scan will take approximately 2-2.5 hours for the entire procedure, with the scan lasting from 20-30 minutes.

Gallium-68 Dotatate

This radiopharmaceutical is used for staging or restaging neuroendocrine or carcinoid tumours and for assisting in selecting the most appropriate treatment.

There is no need to fast for this scan; however it is preferred for you to be well-hydrated.

If sedation is required due to severe claustrophobia, you will need someone to accompany you home and will not be able to drive yourself.

A DOTATATE PET scan will take approximately 2-2.5 hours for the entire procedure, with the scan lasting from 20-30 minutes.

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