What is computed tomography (CT), and how does it work?
CT is a structural imaging technique that uses x-rays to create tomographic (cross-sectional) images. A patient is placed onto a scanner table and passes through the CT gantry, which contains an x-ray tube and an oppositely located array of x-ray detectors that rotate together about the patient ( Figure 2-3 ). A large number of x-ray projections are obtained from multiple angles at each slice position in the patient, each of which contains data regarding the differential attenuation of x-rays by different tissue types in the patient. These projections are then used by a computer to reconstruct CT image