A PET scan, or Positron Emission Tomography scan, is an imaging technique that allows physicians to examine many organs of the body and is helpful in diagnosing many diseases, such as cancer. Other techniques, such as CT scan or MRI, only show organ structure, where as PET shows organ structure and function.
PET is able to differentiate between malignant and benign tumors since it shows how the organ functions. PET can detect if a disease has moved from one part of the body to another, which is not evident clinically or through routine imaging. By uncovering abnormalities that might otherwise go undetected, PET guides physicians to the most appropriate treatment.