Positron emission tomography (PET) scan
PET stands for Positron Emission Tomography. A PET scan shows up changes in your body tissue that are using lots of glucose for energy. This could be caused by a tumour, although there are many other causes.
A PET scan can tell the difference between scar tissue and a cancer, and it may be used to diagnose a cancer, show what stage it is, or see how well you’re responding to treatment.
You may be asked not to eat anything for six hours before the scan, depending on which part of your body is being scanned. You’ll be told this before your appointment.
I was in the scanner two hours but the advantage is that you don't have to hold your breath or anything silly like that. You would just lie there and go to sleep if you want to and it's totally painless.
Someone who was diagnosed with Hodgkin Lymphoma aged 14 talking about his PET scan.
You’ll be given a gown to wear. A small injection of a sugary fluid with a very small amount of radioactivity in it is given into a vein in your arm. Your body uses sugar for energy, so the sugar is taken up by active cells like cancer cells, which grow and multiply quickly. The more active the cells are, the more sugar is taken up. The injection uses a tiny amount of radioactivity, which soon leaves your body.
After the injection, you’ll have to wait 30 minutes to give it time to go around your body. You’ll lie on a couch that can be quite hard, and then the scanner will move over you - it surrounds you but is open at both ends. The scan lasts for about an hour.
A PET scan is painless and you can go home afterwards. Some people find it difficult to lie still, and some people find that they feel anxious and/or a bit claustrophobic. If you let the doctor know beforehand, they’ll be able to help you through it better. If you’re very anxious, they may give you a tablet or injection to help you relax. Closing your eyes and thinking about something else can be helpful. You can listen to music when you’re having the scan, so take a CD in with you and listen to something to take your mind off it!
A specialist will look at the scan and send the results to your doctor. Your doctor will be able to tell you when you’ll get the results.