A PET-CT scan is a combination of PET (positive emissions tomography) and a CT (computerised tomography) scan. CT scans take a series of x-rays to build up a three dimensional picture. A PET scan uses low dose radiation to measure the activity of cells in different parts of their body.
PET-CT scans give more detailed information about the part of the body being scanned.
You may be asked not to eat for up to 6 hours before the scan but you may be able to drink. About an hour before the scan a mildly radioactive substance is injected into a vein, usually in your arm. The amount of radiation used is very small.
The scan takes about 30 to 60 minutes and you should be able to go home afterwards. PET scans are not available at all hospitals so you may have to travel to a specialist centre to have one.