PET CT Scan

A positron emission tomography scan is a type of imaging test. It uses a radioactive substance called a tracer to look for disease in the body. A positron emission tomography (PET) scan shows how organs and tissues are working. This is different than MRI and CT scans. These tests show the structure of, and blood flow to and from, organs.
Machines that combine the PET and CT images, called a PET/CT, are commonly used.  

How the Test is Performed

A PET scan uses a small amount of radioactive tracer. The tracer is given through a vein (IV). The needle is most often inserted on the inside of your elbow. The tracer travels through your blood and collects in organs and tissues. This helps the radiologist see certain areas more clearly. You will need to wait as the tracer is absorbed by your body. This takes about 1 hour.Then, you will lie on a narrow table that slides into a large tunnel-shaped scanner. The PET detects signals from the tracer. A computer changes the signals into 3D pictures. The images are displayed on a monitor for your health care provider to read. You must lie still during the test. Too much movement can blur images and cause errors.How long the test takes depends on what part of the body is being scanned.