A PET scan produces three-dimensional, colour images that show how the tissues inside your body work. PET stands for positron emission tomography.
A PET scan works by detecting a radioactive substance inside the body and making images that show where the radiation is concentrated. Radiation is introduced into the body before a PET scan using a medicine called a radiotracer. This builds up in the part of your body that will be examined.
A PET scan can be used to diagnose a condition or to see how a condition is developing. It can also measure how well a treatment is working (see Why it is necessary, above).
Safety
The amount of radiation used is very small, so it will not damage your body (see Risks, above).
However, tell your doctor or specialist if you are pregnant or breastfeeding. Radiation could be harmful to your baby unless you take precautions.
A PET scan is painless and you should be able to go home on the same day. You are unlikely to have any side effects and you can carry on with daily activities as normal.
Availability
Currently, only a few hospitals have the facilities to carry out PET scanning. You may have to travel to have a PET scan, depending on what facilities are available in your area.
Continue to next section: Why a PET scan is used