Procedure Description:

What is a PET/CT Scan?

A PET (positron emission tomography) scan creates an image of your body's metabolic activity and shows the rate at which your body's cells break down and use sugar (glucose), use oxygen and looks at blood flow. It helps to evaluate how well organs and tissues are functioning.

This is done by injecting a small amount of radioactive material (FDG) into your blood stream and waiting for it to disperse to the area of focus. Depending on the type of nuclear medicine exam you are undergoing, the radiotracer is either injected into a vein, swallowed or inhaled as a gas and eventually accumulates in the organ or area of your body being examined, where it gives off energy in the form of gamma rays. This energy is detected by a device called a gamma camera, a (positron emission tomography) PET scanner and/or probe. These devices work together with a computer to measure the amount of radiotracer absorbed by your body and to produce special pictures offering details on both the structure and function of organs and tissues.

A CT (computed tomography) scan is a noninvasive medical test that uses special x-ray equipment to produce multiple images or pictures of the inside of the body and a computer to join them together in cross-sectional views of the area being studied.

CT scans of internal organs, bone, soft tissue and blood vessels provide greater clarity than conventional x-ray exams.

A PET-CT is a relatively new diagnostic imaging exam that combines the functional information from a PET scan with the anatomical information from a CT scan. When a CT scan is superimposed over a PET scan, doctors can pinpoint the exact location of abnormal activity. They can also see the level and extent of that activity. Even when an abnormal growth is not yet visible on a CT scan, the PET scan may show the abnormal activity.

What Are Some Common Uses?

PET CT's are used in the treatment of cancer, to detect cancer, to determine whether a cancer has spread in the body, to assess the effectiveness of a treatment plan, such as cancer therapy, and to determine if a cancer has returned after treatment.

They are also used to evaluate blood flow to the heart muscle, and to determine the effects of a heart attack on areas of the heart. This can help doctors identify areas of the heart muscle that might benefit from a procedure such as angioplasty or coronary artery bypass surgery (in combination with a myocardial perfusion scan).

PET CT is also used to evaluate brain abnormalities, such as tumors, memory disorders and seizures and other central nervous system disorders, as well as to map normal human brain and heart function.