What does the "CAT" in CAT scan stand for?

CAT stands for Computerized Axial Tomography, the older name for a CT scan. The technique uses X-rays and computer processing to create cross-sectional images, or “slices,” through the body. By combining many measurements taken from different angles, a scanner builds a detailed picture that ordinary projection X-rays cannot provide.

The term is also commonly written as “computed axial tomography.” Modern medical writing usually shortens it to computed tomography, or CT, because current scanners can reconstruct images in multiple planes and three dimensions rather than only along one axis.

The first practical CT scanner was developed by British engineer Godfrey Hounsfield at EMI in the early 1970s. Physician Allan Cormack developed important mathematical methods behind the technology. Hounsfield and Cormack shared the 1979 Nobel Prize in Physiology or Medicine for their work. “Tomography” comes from Greek words meaning “slice” and “to write.”