The scan uses a special dye containing radioactive tracers (Isotope labelled Glucose molecules). These tracers are either swallowed, inhaled, or injected into a vein in the arm depending on what part of the body is being examined. Certain organs and tissues then absorb the tracer.
When detected by a PET scanner, the tracers let the doctor see how well the organs and tissues are working.
The tracer will collect in areas of higher chemical activity, which is helpful because certain tissues of the body, and certain diseases, have a higher level of chemical activity. These areas of disease will show up as bright spots on the PET scan.