Last update:
April 27, 1998

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The Mathematics of CAT Scans

Useful Shadows

In much the same way that a light bulb will cast a shadow of your hand, an X-ray creates a two-dimensional "shadow" of a three-dimensional object.

comparative shadows

The appearance of this shadow is determined by the amount of x-ray energy absorbed by the object. Different body tissues absorb varying amounts of x-ray energy. It is this difference in absorption that allows CAT machines to reconstruct the original 3-D object from a collection of x-ray images.

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