special subjects
Computed Tomography (CT)
Introduction
Computed tomography (CT) is a type of medical imaging that combines a series of x-rays to create cross-sectional, detailed images of internal structures. In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually has 4 to 64 or more rows of sensors that record the x-rays that pass through the body. Data from the sensors represent a series of x-ray measurements taken from multiple angles all around the person. However, the measurements are not viewed directly but are sent to a computer. The computer converts them into images that resemble 2-dimensional slices (cross-sections) of the body. The computer can also construct 3-dimensional images from the recorded images. (See also Overview of Imaging Tests .) 