What is PET?

PET stands for Positron Emission Tomography, an imaging technique that uses small quantities of a radioactive tracer similar to sugar (18Fluorodeoxyglucose) to produce images showing how your body is functioning. PET visualises active tissue and cells as opposed to the body’s anatomy and structure.

How does PET work?

You will be injected with a small quantity of a radioactive tracer that acts like glucose and travels all around the body. This tracer collects in active areas of your body, such as cancer cells and is imaged using a PET scanner.

What is PET used for?

PET is primarily used in imaging cancer and can provide doctors with useful information at many stages of the disease process, such as diagnosis, staging or treatment evaluation. Applications for PET in cardiology and neurology are also on the increase.

What do I need to do before my PET scan?

Please contact us prior to your appointment if you:

• Are diabetic
• Are pregnant, breastfeeding or in contact with small children
• Have any disability or special needs requiring ramp access
• Weigh over 100kg (16 stone)
• Are booked for any other appointments on the same day
• Suffer from allergies or asthma

Please do not have anything to eat or drink for 6 hours prior to your appointment (except water). We encourage you to drink plenty of water on the day of the scan (approximately 4 to 5 glasses) as this helps to flush the tracer we administer through your body.

It is imperative that you arrive on time for your appointment. If you are unable to attend or are going to be delayed, please ring us at the earliest opportunity.


What will happen during your scan?

When you arrive at the centre you may be asked to change into a patient gown and to remove any jewellery or metallic objects. The procedure will be fully explained by one of our technologists, who will also take a brief clinical history. If our clinicians require you to have a mild sedative (in tablet form), it will be given to you at this stage.

Once you have changed into your gown, we will give you an injection of radioactive sugar into a vein - usually your arm. This is similar to a blood test. There are no side effects from the injection and it will not make you feel any different.

After receiving the injection you will need to rest and remain lying down for 1 hour while the injection is absorbed into your body.

Once the radioactive tracer has been absorbed into the body, you are ready for your scan. In the scanning room, you will be asked to lie down on your back on the scanning bed. The bed will move through the ring of the scanner and collect images for between 30 to 60 minutes, depending on the type of scan that you need.

What can you expect after your scan?

After the scan has been completed you are free to change back into your clothes and leave immediately. We recommend that you don’t have close contact with pregnant women or young children for 8 hours after the scan. You are encouraged to drink plenty of fluids of any type as this will help flush any excess tracer through your kidneys.

The results of you scan will be analysed by a Nuclear Medicine Consultant who will provide your doctor with a comprehensive report. Your doctor will then discuss the findings of the report with you and plan any treatment or next steps.


If you have any questions or concerns that we have not answered, please don’t hesitate to contact us on 0207 935 7711 or by sending us an email.