Positron emission tomography (PET) and computerized tomography (CT) are both state-of-the-art imaging tools that allow physicians to pinpoint the location of metabolically active tissues within the body. Cancer cells are frequently more metabolically active than normal tissues and in many cases PET scan examination can be used to distinguish normal from cancer cells in your body. The highly sensitive PET scan images the biology of disorders at the molecular level, while the CT scan provides a detailed picture of the body's internal anatomy. The PET/CT scan combines the strengths of these two well-established imaging modalities into a single examination.