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PET-CT scan - PSMA - 68Ga

Patient information A-Z

What is a PET-CT scan?

PET-CT (positron emission tomography and computerised tomography) is a scanning method that allows us to see how organs are working and helps us identify organs or tissues that are not working normally. For your procedure, the body is imaged following the injection of a radioactive tracer. The tracer is Gallium-68 PSMA. This provides important information about many conditions affecting different organs and the images allow your doctor to plan your treatment more effectively.

What are the benefits?

PET-CT combines two types of imaging in one scan. Your doctors get functional information from the PET scan as well as organ anatomy from the CT scan to check if your organs and tissues are functioning normally.

Are there any side effects or risks?

The scan involves an injection of a small amount of a radioactive tracer which will remain in your body for a few hours. This radiation can cause cell damage that might, after many years or decades, contribute to the development of cancerous cells. However, this procedure carries only a very small chance of this happening to you.

Very rarely there may be bruising at the site of the injection.

Your doctor has considered the risks and benefits of having this test before referring you to us. The benefits of the test outweigh the potential risks.


This scan forms part of a series of investigations your doctor will be undertaking. There is no equivalent scan we can use.

Do I need to confirm my appointment?

No, but the tracer we use will be ordered for you and cannot be used for any other patient. It is important you inform the department if you are unable to attend your appointment. Please help us to conserve valuable NHS resources.

Your scan will take place in the PET-CT department of Addenbrooke’s Hospital. It is vital that you arrive on time for your appointment as the radioactivity has a very short shelf life. If you are late for your appointment we may not be able to proceed with your scan.

Please call us on 01223 349222 to confirm / change your appointment and to inform us if you:

  • are pregnant, breast feeding, or have young children at home
  • have any disability or special needs requiring ramp access
  • have been told you have difficult veins to cannulate
  • weigh over 100kg (16 stone)
  • are claustrophobic
  • have any difficulty lying flat for 20 minutes
  • have any other appointments on the same day

Do I need to prepare for my scan?

There is no specific preparation for this scan. You may eat and drink normally.

Please consider leaving all jewellery at home as we will need you to remove metallic objects for the scan if possible. We suggest wearing something loose and comfortable. If required, a hospital gown can be provided for the scan.

Can I bring someone with me?

Any friends or relatives bringing you to your appointment will not be allowed to stay in the unit due to limited waiting room space. Only an essential carer or interpreter is permitted. Please note that during your scan, they will be asked to wait outside the scan room due to the limited space.

Please do not bring children or pregnant friends or relatives with you.

Ensure that you adhere to current Trust COVID-19 guidelines regarding the attendance of appointments.

How long will I be in the department for?

You should expect to be with us for approximately two hours. This includes explanation, preparation and scanning time.

What will happen on the day of the scan?

Once you arrive for your appointment you will be taken into the interview room and the procedure will be fully explained by one of our radiographers / technologists who will also take a brief clinical history. If you have any questions, this is a good opportunity to ask them.

A small needle will be inserted into a vein in your arm, hand or foot. A small amount of a radioactive tracer will be injected through this needle. You will then lie and relax quietly for 60 minutes before having the scan.

Just before your scan, you will be asked to empty your bladder and to remove all jewellery and metallic objects. We will then ask you to lie on your back on the scanner bed with your arms placed above your head if possible, otherwise arms down by your side. Most scans last between 10 and 20 minutes.

What happens after my scan?

You are free to go home and you may eat and drink as normal. Continue to drink plenty of fluids for the remainder of the day and empty your bladder regularly.

Please avoid close contact with pregnant women and young children for six hours after your scan.

If you are breastfeeding, we recommend that you:

  • express and appropriately store at least one feed before your appointment
  • breastfeed your child before your appointment
  • express as much milk as you can in the two hours after your scan and discard the milk
  • ideally, have someone else bottle feed the stored milk to your child until the end of your six-hour contact restriction

When will I get my results?

Your results will be sent to the doctor that requested your scan. Results are usually with your doctor within a week.

If you have a further appointment with your doctor, please let us know the date when you attend for your scan.

Further information

For further information, you can contact the PET-CT team on 01223 349222.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151