Having your scan

This information tells you about having a PET-CT scan with us (following referral by your doctor) and aims to answer any questions you might have. On this page we aim to provide you with important information about the procedure and answer any questions you may have.

Please read this information carefully and if there are any questions or concerns then contact us on 01923 844092.

What is a PET-CT scan?

A PET-CT scan is a combination of two types of scanning technique in which a small amount of radioactive tracer (a type of chemical) is injected into a vein. This provides information about the anatomy (CT) and function (PET) of your internal organs. The scan tells doctors about the presence, location and severity of cancers. It can also be used for other conditions such as infection or inflammation and conditions that affect the brain. We are able to provide important information to help your doctor plan an appropriate treatment for you.

The PET-CT scanner is a large, quiet machine with a ring-like structure. You will need to be able to lie on your back on the scanning couch, which will move into the ring.

What are the risks of having a PET-CT scan?

The radioactive tracer has no documented side effects. The scan involves exposure to radiation in the form of gamma and X-rays. We ensure that the radiation dose you receive is both appropriate to address the clinical question being asked, and is as low as is achievable. A typical PET-CT scan radiation dose is equivalent to around 5 years of average background radiation which we all receive in the UK.

The doctor who has referred you to us has judged that the risk of the radiation dose is outweighed by the potential benefits of the scan.

Before your scan appointment

Please inform us if the answer to any of the following is yes:

  • Are you diabetic?
  • Have you had chemotherapy or radiotherapy within the last two weeks?
  • Have you had surgery within the last three weeks?
  • Have you had a recent infection or are feeling unwell?
  • Are you pregnant, trying to get pregnant or breastfeeding?
  • Have you had previous MRI/CT scans that you have found difficult to tolerate or are you claustrophobic?
  • Do you have any additional needs (for example disabilities or mobility issues)?
  • Do you need hospital transport? If yes, this is something the team who referred you for your scan can help you with.
  • Do you need an interpreter?
  • Do you have any other appointments booked on the same day as this scan?
  • You weigh over 225 kg or 35 stones
  • If you need a chaperone

Preparing for your scan

  • Have nothing to eat for six hours before your appointment time (4-6 hours if you have diabetes). This includes chewing gum, mints, cough drops and Nicorette gum. Drink plenty of plain water and not flavoured waters.
  • If you have a feeding tube, do not have anything (except water) through it for six hours prior to the scan.
  • Please continue to take medications as usual unless instructed otherwise by your referring doctor. If you have to take any medications with food, ask your doctor for further advice.

Please avoid strenuous exercise for 24 hours before your appointment. For example, running, cycling, horse riding and gym exercise. You need to be as relaxed and rested as possible.

On the day

Please bring a dressing gown or warm, loose, metal-free clothing

You can take all your usual medicines unless otherwise instructed - if in doubt, please contact us, especially if you are diabetic

Please come to the Paul Strickland Scanner Centre reception 15 minutes before your appointment time. It’s very important you arrive on time because the radioactive tracer that we inject is ordered specifically for you and only works for a short time. If you are late we may therefore not be able to proceed with your scan.

If you are unable to attend or are going to be delayed, please telephone us at the earliest opportunity on 01923 844092.

Important information about your PET-CT scan

Sometimes, due to the complexity of both the scanner and the chemical tracer that is injected, we can experience unforeseen technical difficulties which could mean we’re unable to scan you on the day. If this happens, we may need to cancel your appointment at short notice but we will rebook you for the first available convenient date.

Bringing a friend, relative or carer?

You can bring a relative, friend or carer but they will have to wait in the waiting room unless you need their help with translation or have any special requirements.

Please do not bring children or pregnant friends/relatives with you or we may be unable to scan you.

Having your PET-CT scan

  • A radiographer or technologist will accompany you to a private room, ask you about your medical history and explain what will happen.
  • We will give you an injection of the radioactive tracer
  • We will ask you to relax in a resting bay for the first half an hour to allow the injection to be absorbed into the body.
  • You will wait a further 30 minutes before your scan is due
  • Immediately before your scan, we will ask you to remove any metal items and empty your bladder.
  • We will then take you into the scanner room and ask you to lie on your back on the scanning bed.
  • The scan will usually take between 20 to 60 minutes
  • The radiographer or technologist will operate the scanner from the next room where you can be assured that they can see and hear you at all times via a connecting window and intercom. The scanner is not noisy and having a scan is not painful.
  • Once the scan is complete you are free to leave as soon as you feel ready.
  • You may eat and drink as you normally would. Drink plenty of fluids and empty your bladder frequently.
  • We recommend that you avoid contact with pregnant women and young children for 10 hours after the injection.


Watch video in another language.

After the scan

If you are awaiting transport to collect you, please feel free to bring something along to eat and drink.

Getting your results

One of our PET-CT specialists will analyse your scan. We will then send your report back to the doctor who referred you in time for your next appointment with them.

If you do not have another outpatient appointment arranged and you do not hear anything about the results within three weeks, we suggest that you telephone the referring doctor’s secretary for advice.

Your feedback

We strive to provide our patients with our world class scanning facilities, clinical excellence, innovative research and enabling early diagnosis.

We welcome any feedback that you may have to enable us to improve our patient care and experiences.

Where to get more information