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Positron Emission Tomography (PET)

Positron Emission Tomography (PET) scans show tissue and organ function by examining chemical activity in the body.

PET scans can reveal problems at a cellular level, sometimes detecting disease before it shows up on other imaging tests. It can be helpful in diagnosing cancer, heart disease, brain tumors, and Alzheimer’s disease. It can also help evaluate the effectiveness of certain cancer treatments.

The procedure measures blood flow, sugar metabolism, and oxygen use. Certain diseases are indicated by higher levels of chemical activity. Cancer cells, for example, often show up as bright spots on Positron emission tomography because of their higher metabolic rates. A PET scan can also determine whether cancer has spread. Heart disease might appear through a PET scan as decreased blood flow in the heart.

What Happens During a PET Scan?

A PET scan is a painless, low-risk outpatient procedure that lasts about two hours. They are performed about 2 million times per year in the United States. Patients are given a very small dose of a radioactive chemical, called a tracer, prior to the scan. The tracer will take up to an hour to be absorbed by the body. Patients lie on a table that will move into a doughnut-shaped scanner. During the test, patients will be asked to lie still so that the images will be clear.

If a patient anticipates feeling claustrophobic during the scan, they should consult their physician about possible preparations. Pregnant women should talk to their doctors about the benefits and risks of PET scans. Your UTHealth Neurosciences team will discuss the results with you and, as needed, develop a personalized treatment plan.

Tests and Treatments


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At UTHealth Neurosciences, we offer patients access to specialized neurological care at clinics across the greater Houston area. To ask us a question, schedule an appointment, or learn more about us, please call (713) 486-8000, or click below to send us a message. In the event of an emergency, call 911 or go to the nearest Emergency Room.


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