[MOL] Pet Scan Info Series-Part 6 [01649] Medicine On Line

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[MOL] Pet Scan Info Series-Part 6

Positron Emission Tomography (PET) provides physicians with information about the body's chemistry not available through any other procedure. Unlike CT or MRI, which look at anatomy or body form, PET studies metabolic activity or body function. PET has been used primarily in cardiology, neurology, and oncology. In particular, it has been used to assess the benefit of coronary artery bypass surgery, identify causes of childhood seizures and adult dementia, and detect and grade tumors.

In PET the patient receives a short half-lived radiopharmaceutical (produced by a cyclotron or a generator). Because the radioisotope used in a PET scan is short-lived, the amount of radiation exposure the patient receives is about the same as from two chest X-rays. The radiopharmaceuticals discharge positrons from wherever they are used in the body. As the positrons encounter electrons within the body, a reaction producing gamma rays occurs.

The patient lies on a table that slides into the middle of the scanner. Within the scanner are rings of detectors containing special crystals that produce light when struck by a gamma ray. The scanner's electronics record these detected gamma rays and map an image of the area where the radiopharmaceutical is located. Since the radiopharmaceutical contains a chemical commonly used by the body, PET enables the physician to see the location of the metabolic process. For example, glucose (or sugar, which the body uses to produces energy) combined with a radioisotope will show where glucose is being used in the brain, the heart muscle, or a growing tumor.

More information on PET

You can go to our links page or use these external resources.

  • UCLA's Brochure Positron Emission Tomography (PET) - The Power of Molecular Imaging
  • UCLA's Let's Play PET on-line tutorial, which provides a detailed explanation of the physical and medical basis of Positron Emission Tomography
  • Institute for Clinical PET
  • Society of Nuclear Medicine