Tomography is derived from the Greek words tome (meaning section or slice) and graphia (meaning writing). Computed
tomography, also known as CT scan or CAT scan (for computed axial tomography), refers to a technique capable of
generating 3-D images of X-ray attenuation (absorption) properties of an object. This is in contrast to the traditional,
X-ray technique that produces only a 2-D profile of the object (Fig. TF6-1). CT was invented in 1972 by British electrical
engineer Godfrey Hounsfield and independently by Allan Cormack, a South African-born American physicist. The
two inventors shared the 1979 Nobel Prize in Physiology or Medicine. Among diagnostic imaging techniques, CT
has the decided advantage in having the sensitivity to image body parts on a wide range of densities, from soft tissue
to blood vessels and bones.