The difference between thin layer CT and conventional CT depends mainly on the size of the observed lesion. It is important to know that both thin and thick layers use the same CT equipment, and whether a thick or thin layer scan is used depends mainly on the object of observation. When scanning a lesion the size of a potato, a thick layer scan will bring out the features. However, for the display of lesions the size of rice, thin layer CT is needed because the smaller the object of observation, the thinner the CT used. Nowadays, CT at county-level hospitals and hospitals above the county level all use CT with 16 rows or more, and routinely scan patients with thin-layer CT, and doctors observe images from thin-layer CT scans when making diagnoses, but when giving films, because the thin-layer images are huge, they reconstruct the thick-layer images and print them on the film.