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The Secret Life of the Brain
History of the Brain 3-D Brain Anatomy Mind Illusions Scanning the Brain The Episodes:
Scanning the Brain Explore brain scanning technology:
CAT - Computerized Axial Tomography

CAT scan
High resolution magnetic resonance image of normal brain with CAT scan.

Developed in the 1970s, CAT (or CT) scanning is a process that combines many 2-dimensional x-ray images to generate cross-sections or 3-dimensional images of internal organs and body structures (including the brain). Doing a CAT scan involves putting the subject in a special, donut-shaped x-ray machine that moves around the person and takes many x-rays. Then, a computer combines the 2-dimensional x-ray images to make the cross-sections or 3-dimensional images.

CAT scans of the brain can detect brain damage and also highlight local changes in cerebral blood flow (a measure of brain activity) as the subjects perform a task.

CAT scan
CAT scan of normal brain.
Photo by Monte S. Buchsbaum, M.D.




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