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PET-CT scan - 11C Metomidate

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. PET-CT helps us identify organs or tissues that are not  working normally. The body is imaged following the injection of a radioactive tracer. For your procedure, the tracer is Carbon-11 Metomidate. This provides important information about many conditions affecting different organs and these 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 can, after many years or decades, contribute to the development of cancerous cells. 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 will have considered the risks and benefits of having this test before referring you to us. The benefits of the test outweighs the potential risks.


This scan forms part of a series of investigations your doctor will be undertaking. There is no equivalent scan to this study.

Do I need to confirm my appointment?

No, but if you are unable to attend or have any other queries then please telephone the department. This way we can give your appointment to another patient if appropriate.

The tracer we use is extremely expensive and cannot be reused. It has been specially ordered for you. Please help us to conserve valuable NHS resources.

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 on01223 349222 to confirm/change your appointment and to inform us if:

  • are pregnant, breast feeding, or have young children at home
  • have any disability or special needs requiring ramp access
  • have been told that you have difficult veins to cannulate
  • weigh over 100kg (16 stone)
  • are claustrophobic
  • have any difficulty lying flat for 25 minutes
  • have any other appointments on the same day

Preparing for your scan

  • You should drink plenty of plain water. Please avoid flavoured water.
  • Take all prescribed medications on the day of your scan as usual, unless otherwise instructed by your doctor.
  • Please leave all jewellery at home as we need you to remove all metallic objects for the scan. We suggest wearing something loose and comfortable, a hospital gown will be provided for the scan.
  • You do need to be able to lie flat for this scan. Please inform us if you do not think you can manage this.

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 between 1 and 1.5 hours. This includes explanation, preparation and scanning time.

What will happen on the day of the scan?

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 radioactive tracer will be injected through this needle. You will then lie and relax quietly for 30 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. The scan takes 25 minutes.

Please note that due to the complex processes involved in the manufacture of these tracers, there may be delays and on occasion there may be failures in the production or quality control testing of the tracers. We will keep you updated of any delays.

What happens after my scan?

  • You are free to go home.
  • 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 2 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 who requested your scan. Results are usually with your doctor within a week or two, often much sooner.
  • 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