PET scan

A PET (positron emission tomography) scan uses a small amount of radiation to diagnose or monitor your cancer. 

Before the scan, a low dose of radiotracer (radioactive sugar) is injected into your arm. An hour or so later, you will have the scan. The PET scan uses the radiotracer to highlight cancer cells in your body. This can give your doctor more information about where the cancer is or if it has spread to other tissues and organs. 

You may be asked not to eat and to drink only plain unflavoured water for around 6 hours before the test. You may be asked to avoid sugar or caffeine for a time too.

You may be asked to avoid strenuous exercise for 24 hours before the scan.

You will need to remove any jewellery and any other objects containing metal. 

You may be asked to change into a hospital gown. 

• You will have an injection of radioactive sugar into your veins, usually in your arm.
• You will have to wait for around an hour for the sugar to travel around your body. You will be asked to lie still and try to relax during this time.
• You might like to bring earphones so you can listen to music or a podcast while you’re waiting.
• The radioactive sugar shows up where the cancer cells are, so your doctor can see if the cancer has spread to other tissues and organs.

After the injection you will have to wait about an hour before having the scan, to let the radioactive sugar spread through your body. The scan itself usually lasts between 20 minutes and an hour.

About an hour after the injection, you will have a scan. 

You will lie on a table which moves through a scanning ring. 

You will be asked to stay still during the scan. 

The radiographer will be in another room, they will be able to hear you and speak to you during the scan. 

You will be slightly radioactive after the PET scan, so you should not have close contact with pregnant women, babies or young children for a few hours after the scan. Drink plenty of fluids and empty your bladder regularly after the scan. This can help flush the radiotracer from your body.