PET-CT scan

A combination of a PET scan and a CT scan to give detailed images of inside your body.


There are two parts to this type of scan – a PET scan and a CT scan. Both are carried out at the same time. A PET scan shows how the tissues and organs inside your body are working.

A CT scan uses X-ray and a computer to create a detailed 3D picture. Our CT scanner can carry out a full body scan in just 10 seconds.

As part of the PET scan, you will be injected with a radioactive substance called a radiotracer (isotope). This builds up in different areas of the body and helps to show up any abnormalities.

How to prepare for a PET-CT scan

You must let us know if you are pregnant or breastfeeding as this type of scan is not recommended.

You will need to fast for a number of hours before the scan. This means you won't be able to eat any food but you can drink water. This helps the tracer to be absorbed into the body. You'll be given full details on how on long to fast for beforehand.

If you have diabetes you will be given a late morning appointment, so you can have a light breakfast with your medication, and fast for 4 hours before your appointment. If you don't have diabetes or diet-controlled diabetes, you will need to fast for 6 hours before your appointment.

You will need to change into a hospital gown and empty your bladder before your appointment. You may also need to remove any jewellery.

How is a PET-CT scan carried out?

A PET-CT scan is carried out by a nuclear medicine technologist (a healthcare professional trained to handle isotopes).

You will be given an injection of a radiotracer (isotope). Then you will be asked to rest quietly in your own individual room. Family and friends will need to wait in outside in the waiting area.

During the scan, you will lie on a table that moves backwards or forwards slowly. The table will be positioned so that the part of your body that's being scanned is in the centre of the scanner.

The whole procedure can take up to two hours, with the actual scan time taking 30-40 minutes.

What to expect after a PET-CT scan

We will let you know at the time of the scan if there is anything special you need to do after the procedure.

Usually, you'll be able to leave the hospital straight away, and have something to eat.

The isotope will pass naturally out of your body fairly quickly. Make sure you drink plenty of liquid and go to the toilet often, as this will help pass the isotope out of your body.

The amount of radiation in your body after the scan will be very small and there is little risk of contaminating another person. If you are worried about exposure to radiation please talk to one of our team.

A report will be sent the doctor who requested your scan, usually the next working day. You'll be able to get the results of your scan at your next appointment.

What are the alternatives?

Your consultant will explain your options and let you know which procedure is most suitable for you.

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