Positron emission tomography, also called PET imaging or a PET scan, is a type of nuclear medicine imaging. A PET scan measures important body functions, such as blood flow, oxygen use, and sugar (glucose) metabolism, to help doctors evaluate how well organs and tissues are functioning.
PET is a powerful diagnostic test that is having a major impact on the diagnosis and treatment of disease. A PET scan (positron emission tomography scan) monitors the biochemical functioning of cells by detecting how they process certain compounds, such as glucose (sugar). PET can detect extremely small cancerous tumours, subtle changes of the brain and heart, and give doctors important early information about heart disease and many neurological disorders, like Alzheimer's.
Most common medical tests, like CT and MRI scans, only show details about the structure of your body. PET scans give doctors images of function throughout the entire body, uncovering abnormalities that might otherwise go undetected. This allows doctors to treat these diseases earlier and more accurately. A PET scan puts time on your side. The earlier the diagnosis, the better the chance for treatment.
For example, a PET scan is the most accurate, non-invasive way to tell whether or not a tumour is benign or malignant, sparing patients expensive, often painful diagnostic surgeries and suggesting treatment options earlier in the course of the disease. Although cancer spreads silently in the body, PET can inspect all organs of the body for cancer in a single examination.
Today, most PET scans are performed on instruments that are combined PET and CT scanners. The combined PET/CT scans provide images that pinpoint the location of abnormal metabolic activity within the body. The combined scans have been shown to provide more accurate diagnoses than the two scans performed separately.