Positron Emission Tomography/Computed Tomography (PET/CT)

Positron emission tomography (PET) is a nuclear medicine test that detects changes in cell function and metabolism. This requires injecting a patient with a small amount of a radioactive material (tracer) that will accumulate in a certain organ. A PET scan is more sensitive than CT in detecting many types of cancer.

A computed tomography (CT) scan uses X-rays to create more detailed, cross-sectional pictures of the body. A PET/CT exam combines these two imaging methods. By combining PET with CT, better localization of disease is possible than using PET alone. The PET scanner shows metabolism and function of cells, while the CT scanner shows detailed anatomy. 

For example, a PET scan can give information about the metabolic function of cancer cells, while the CT scan shows the exact location, size and shape of the cancerous growths. Using computers, PET and CT scans are fused to produce a single scan. When the results of PET and CT scans are “fused” together, the combined image provides complete information on disease location and metabolism.

PET/CT is used to evaluate many diseases, especially cancer and the effects of cancer therapy. PET/CT is also used to diagnose heart disease and brain disorders.