Molecular Imaging Program

Patient Information

Cyclotron Operations, a part of the Center for Quantitative Cancer Imaging at Huntsman Cancer Institute at the University of Utah (HCI), manufactures imaging agents called radiotracers for research purposes and clinical needs throughout the Wasatch Front.

These radiotracers are commonly used in positron emission tomography (PET), a noninvasive procedure that helps in the diagnosis and treatment of cancer. PET imaging provides information about the body's chemistry not available through any other procedure. Unlike computed tomography (CT) or magnetic resonance imaging (MRI), which look at anatomy or body form, PET shows function and physiology.

What is PET?

Positron Emission Tomography (PET) provides information about the body's chemistry not available through any other procedure. Unlike computed tomography (CT) or magnetic resonance imaging (MRI) which look at anatomy or body form, PET shows actual biological functioning of the body. PET is used primarily in cardiology, neurology, and oncology. In particular, it is used to assess the benefits of coronary artery bypass surgery versus heart transplant, identify causes of childhood seizures and adult dementia, and detect and distinguish between benign and malignant tumors. PET has become one of the most accurate imaging techniques to detect, characterize, and stage various types of cancer.

During a PET scan, a patient receives a short half-lived radioactive tracer—2-[fluorine-18]–fluoro-2-deoxy-D-glucose (FDG). Because FDG is short-lived, the amount of radiation exposure to the patient is about the same as that from two chest x-rays. Similar in structure to glucose, FDG is the most widely used compound in PET imaging because of the widespread use of glucose by the human body. FDG moves to the area or areas using more glucose where it becomes trapped, helping identify potentially cancerous regions. FDG is a positron-emitting compound. As the positrons encounter electrons within the body, gamma rays are produced. A PET scan patient lies on a table that slides into the middle of the donut-shaped scanner. Within the scanner are rings of detectors containing special crystals that produce light when struck by a gamma ray. The scanner's electronics record these detected gamma rays and map an image of the area where the radioactive tracer has localized.

Since the radioactive tracer contains glucose, PET allows the physician to see the location of a metabolic process. For example, glucose combined with a radioisotope will show where glucose is being used in the brain, the heart muscle, or a growing tumor.

FDG-PET is most commonly used in oncology to detect and evaluate tumors. All cells consume glucose to produce energy, and since cancer cells use more energy than neighboring cells, cancerous tissue appears "hot" or unusually active.