What is the definition or description of: tomography?

Reconstructed image.: Old fashioned tomograms used a moving x-ray source and flat detector to image at a certain depth in a patient. Most commonly this was used to image the kidneys. The most common tomograms used today are in cat scans, or computer assisted tomography. An x-ray source and multiple detectors spin around you, and the data is reconstructed by a computer into a slices, or cross-sections of your body.

"Picture slices": "tomo" comes from the greek word for "cut" or "slice". "graph" comes from the greek word for "writing" or "drawing". Computed tomography (or ct) uses a computer to form/make/draw many separate image slices of the inside of a person's body.