A computed tomography scan or CAT-scan uses
X-rays to create images of the body. However a radiograph (x-ray) and a CAT-scan show different types of information. An x-ray is a two-dimensional picture and a CAT-scan is three-dimensional. By imaging and looking at several three-dimensional slices of a body (like slices of bread) a doctor could not only tell if a tumor is present, but roughly how deep it is in the body. These slices are no less than 3-5 mm apart. The newer spiral (also called helical) CAT-scan takes continuous pictures of the body in a spiral motion, so that there are no gaps in the pictures collected.
A CAT-scan can be three dimensional because the information about how much of the X-rays are passing through a body is collected not just on a flat piece of film, but on a computer. The data from a CAT-scan can then be computer-enhanced to be more sensitive than a plain radiograph.
Inventor of the Cat-scan
Robert Ledley was the inventor of CAT-Scans a diagnostic x-Ray system. Robert Ledley was granted patent #3,922,552 on November 25th in 1975 for a "diagnostic X-ray systems" also known as CAT-Scans.
