PET/CT is a diagnostic imaging tool that combines two scan techniques: positron emission tomography (PET) and computed tomography (CT). It uses a small dose of radiation to create detailed images of structures and function inside your body and can detect problems that don’t show up on other types of diagnostic imaging exams.

Physicians use PET/CT to:

• Detect cancers and to assess the effect of cancer therapy
• Diagnose heart disease and to gauge heart muscle damage after a heart attack
• Scan the brains of patients with specific brain disorders

During a PET/CT scan, you are first injected with a radioactive substance. Lying on a flat table, you move slowly through a donut-shaped machine that detects positrons, tiny particles given off by the radioactive material. The machine takes a series of thin "slice" images, which are then assembled to create a 3-D image of your body.

Computed tomography (CT or CAT scan)

CT is a noninvasive diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce both horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs.

Positron emission tomography (PET)

PET is a specialized radiology procedure used to examine various body tissues to identify certain conditions. PET may also be used to follow the progress of the treatment of certain conditions. PET is a type of nuclear medicine procedure. This means that a tiny amount of a radioactive substance, called a radionuclide (a radiopharmaceutical or radioactive tracer), is injected into the body during the procedure to assist in the examination of the tissue under study. A special type of camera can then detect the radioactivity in the body.