Why It Is Done?
A PET scan is done to:
- Study blood flow and metabolic activity in the brain, which can help identify certain neurologic and central nervous system disorders. These disorders include Parkinson's disease, multiple sclerosis, Alzheimer's disease, transient ischemic attack, amyotrophic lateral sclerosis (ALS), Huntington's disease, epilepsy, stroke, and schizophrenia.
- Diagnose certain types of cancer, especially breast, brain, lung, colon, thyroid, and lymphoma. PET scanning is more sensitive than a CT scan or an MRI for detecting tumors in early stages. It also can help determine whether a tumor is noncancerous (benign) or cancerous (malignant). If cancer has been diagnosed, PET scanning can be done to help determine how far advanced the cancer is and whether it has spread to another area of the body (metastasized). It is often necessary to do both CT and PET scanning to evaluate metastatic cancer.
- Help a doctor determine the most effective treatment for cancer. PET scanning may also be done to help determine whether surgery can be done to remove a brain tumor.
- Detect poor blood flow to the heart, which may indicate coronary artery disease.
- Distinguish healthy from damaged heart tissue, especially during the early stages of a heart attack.
- Help determine the best course of treatment for a person with heart disease. For example, if a PET scan shows that blood flow is reduced to a large area of the heart, but the heart's metabolism is unaffected (which means that the heart tissue is not dead), a person may be a candidate for coronary artery bypass surgery.