Why it's done

A PET scan is an effective way to help identify a variety of conditions, including cancer, heart disease and brain disorders. Your doctor can use this information to help diagnose, monitor or treat your condition.

Cancer

Cancer cells show up as bright spots on PET scans because they have a higher metabolic rate than do normal cells. PET scans may be useful in:

• Detecting cancer
• Revealing whether your cancer has spread
• Checking whether a cancer treatment is working
• Finding a cancer recurrence

PET scans must be interpreted carefully because noncancerous conditions can look like cancer, and some cancers do not appear on PET scans. Many types of solid tumors can be detected by PET-CT and PET-MRI scans, including:

• Brain
• Breast
• Cervical
• Colorectal
• Esophageal
• Head and neck
• Lung
• Lymphatic system
• Pancreatic
• Prostate
• Skin
• Thyroid

Heart disease

PET scans can reveal areas of decreased blood flow in the heart. This information can help you and your doctor decide, for example, whether you might benefit from a procedure to open clogged heart arteries (angioplasty) or coronary artery bypass surgery.

Brain disorders

PET scans can be used to evaluate certain brain disorders, such as tumors, Alzheimer's disease and seizures.