PET scan, or positron emission tomography, is a nuclear imaging technique that is used to view distinct images of the human body, such as the heart or brain, and detect subtle changes in the body’s metabolism and chemical activities.
What is PET scan used for?
PET scans are used to help physicians diagnose and evaluate patients with the following conditions:
- Brain disorders such as epilepsy, Parkinson’s disease, and Alzheimer’s disease
- Brain tumors and other cancers to assess tumor size and growth, determine the stage of cancer, and examine the effects of cancer treatments
- Cardiac illnesses
PET scans are able to detect metabolic changes in the body before structural changes even occur. This allows for earlier diagnosis and treatment, which for many patients can mean the difference between life and death.
How does it work?
The science is fairly complicated, combining physics, chemistry, and nuclear science into one remarkable technology. Simply stated, a PET scan is a digital image of the brain or other part of the body that illustrates and highlights abnormal cells that may indicate a serious illness.
This is accomplished by injecting a glucose-based radioactive pharmaceutical, called a tracer, into the body (it can also be inhaled as a gas). The tracer is then absorbed by the part of the body under examination. Gamma rays emitted by the body are then detected by the scanner and converted into a highly detailed computer image. Abnormal cells (such as cancer) are clearly visible on the imaging screen.
What can I expect during a PET scan?
The PET scanner is a large machine with a hole in the middle. Once you have received the tracer and it has had sufficient time to be absorbed by the body, you will lie on the scan table and slowly move through the scanner. The machine rotates around the body detecting gamma rays and transmitting them to the computer screen monitored by the physician or technologist. You will need to lie very still during the procedure but it will not be painful.
Typically, PET scans take about 30 minutes to two hours, depending on the area of the body being examined. Once the scan is finished you should be able to return to your normal daily activities. You might be instructed to drink extra amounts of fluids following a PET scan to flush the tracer from your body.
