A PET/CT scan combines a CT scan and a PET scan into one scan. The scan takes CT pictures of the structures of the body. At the same time, a mildly radioactive drug shows up areas of the body where the cells are more active than normal. The scanner combines both of these types of information. This allows the clinician to see any changes in the activity of cells and know exactly where the changes are happening.

Before your Appointment

Please do not eat or drink anything (except water) for 6 hours before your scan. Prior to your appointment you should drink plenty of plain water, but please avoid water which is flavoured or diluted with cordial.

Please continue to take your usual medication on the day of the scan including pain killers. Bring your medication with you, should it coincide with your scan time.

Please avoid strenuous physical activity for 24 hours before the scan e.g. Horse riding, exercising in the gym.

Please leave all jewellery at home and wear comfortable clothes that contain little metal, a tracksuit is ideal.  Some patients feel cold on the units even on a warm day, so please bring warm clothes, such as a fleece or a jumper to wear.

You cannot bring friends or relatives to the mobile PET/CT unit. Friends and relatives who accompany you to the unit will have to wait outside the unit, but will be advised when you are ready to leave. This is because of the limited space available on a mobile unit.

Please do not bring children or pregnant friends, because the PET/CT scan uses radiation.

Please contact us prior to your appointment if you:

• Are diabetic
• Are pregnant, breast feeding or have small children
• Are booked for any other appointments on the same day
• Suffer from allergies or asthma
• Have any other queries concerning your examination.

If you need help because you speak a different language, please let us know when you book your appointment.  If you have any queries or need advice please contact us on the number provided in your confirmation letter or by contacting the unit in our 'Locate a Centre' section of the website.

During your Appointment

On arrival our staff will welcome you to the centre, explain the procedure to you, run through a simple safety questionnaire to make sure you can be scanned and answer any further questions you may have.

If our clinicians require you to have a mild sedative (in tablet form), it will be given to you at this stage. We will then give you an injection of radioactive tracer called FDG which will not make you feel any different. You will then rest for approximately 1 hour prior to your scan. During this rest period you will asked not to talk, as this can affect the distribution of the tracer. Depending on the type of scan your doctor has requested, you may be able to read or listen to music during this period so please bring a book or personal music device with you. The rest period is to allow the body time to take up the injection and is important.

You will then be asked to visit the toilet to empty your bladder prior to your scan. This is to ensure the bladder is empty and gives a good view of the pelvic region. Following this you will be taken through for your scan, and asked to lie flat on a narrow scanner 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 you require.

During the entire examination, the radiographer can see you clearly and speak to you, so if you have any problems, you only have to speak. We advise you to allow up to four hours for the whole procedure from arrival to discharge.

After your appointment

The results will be interpreted by a consultant and forwarded to your referring doctor.

After the scan you can eat and drink normally, so please bring something with you to consume on your way home. You should continue to drink plenty of fluids for the remainder of the day to flush the tracer through your body.

We recommend that you don't have close contact with pregnant women or young children for four hours after the scan.

Important information
The 18FDG (the radioactive form of glucose) tracer, has a very short half-life and therefore can not be kept in stock. Production of every dose occurs on the morning of the scan. The manufacturing process is extremely complex and subsequently, on rare occasions, the production may be unsuccessful or of low yield with the consequence that we will have to cancel your appointment. Such incidents are unfortunately out of our control and whilst we will always do our best to honour your appointment, inevitably there will be occasions when this is not possible. In the event of this occurring, we will endeavour to inform you of the cancellation as soon as possible, but this would normally be on the same day as the scan. We will of course issue you with the next available appointment date that is convenient to you.

Frequently Asked Questions about PET/CT

Do I have to undress for the scan?
You will not normally change in to a gown for the scan and will remain in your clothes, female patients will be asked to remove their bra just prior to scan.

How much radiation do I receive from the scan?
The equivalent to a period of a few years natural background radiation for each part of the scan (PET and CT scans). The radiation injected for the scan fades over time, with most of it decaying in the first 6 hours. The radiation has a very short physical half-life (the time taken to reduce the radioactivity by half).

Are there any risks associated with the radiation?
As with any examination involving ionising radiation there is a small degree of risk but this is far outweighed by the benefits of having the study; a PET-CT scan imparts approximately the same radiation dose as an abdominal CT study. All of our units comply with all UK legislation regarding the handling and administration of radioactive substances and conducts regular audits to ensure compliance is maintained.