What is a PET scan?
A positron emission tomography (PET) scan is a type of nuclear medicine imaging test. It is used to examine various body tissues to identify certain conditions by looking at blood flow, metabolism, and oxygen use. PET scans may also be used to see how well the treatment of certain diseases is working.
For a PET scan, a tiny amount of a radioactive substance, called a radioactive tracer is used to show the metabolism of a particular organ or tissue. This test gives the healthcare provider information about the function and structure of the organ or tissue, as well as information about its biochemical properties. A PET scan may detect biochemical changes in an organ or tissue that are signs of a disease process before physical changes related to the disease can be seen with other imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MRI).
Why might I need a PET scan?
In general, PET scans are used to evaluate organs and/or tissues for the presence of disease or other conditions. More specific reasons for PET scans include:
•To diagnose neurological conditions such as:
◦Alzheimer disease and other dementias
•To locate the specific area to be reached during brain surgery
•To evaluate the brain after injury to look for a blood clot or bleeding in, or blood and oxygen flow to the brain tissue
•To detect the spread of cancer to other parts of the body from the original cancer site
•To see how well cancer treatment is working
•To evaluate blood flow heart muscle to determine if treatment is needed to improve blood flow to the heart and to determine the effects of a
•To further identify lung lesions or masses seen on chest X-ray and/or chest CT
•To look for cancers that have come back after treatment and find them earlier than can be done with other diagnostic tests