How It Works

An integrated PET/CT scan combines images from a positron emission tomography (PET) scan and a computed tomography (CT) scan that have been performed at the same time using the same machine. A CT scan provides detailed pictures of tissues and organs inside the body, while a PET/CT scan reveals any abnormal activity. Combining these scans creates a more complete image than either test can offer alone.

The CT scan creates a 3D image of the body with an X-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a vein to provide better detail in the images.

A PET/CT scan also creates 3D pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a vein. This substance is absorbed by the body’s cells depending on how much energy they use. Because cancer cells tend to use more energy than healthy cells, they absorb more of the radioactive substance. The PET/CT scanner then detects this substance to produce images.