Computed tomography (CT)

A radiologic two‐dimensional representation of a three dimensional depiction of a patient’s anatomic structures. The images formed depict anatomic osseous structures that can be measured and examined for dental implant placement. A computer is used to arrange the collected radiographic images into a single view.


A technique for imaging anatomical structures with X ray. Objects are exposed to a series of X-ray beams on a single plane but with an origin at different points around a 180-degree arc. A computer algorithm reconstructs the beam absorption data so as to display an image of absorption values at each point in the plane. The process is repeated for each plane to be imaged. Used for detecting anatomical abnormalities such as strokes, tumor, and atrophy of the brain.


A diagnostic technique using ionizing x-rays passed through a patient around specific sections of the body at multiple angles; useful in the detection of tumors.


Method for examining the body’s soft tissues (e.g., the brain) using X rays, with the beam passing repeatedly (scanning) through a body part, and a computer calculating tissue absorption at each point scanned, from which a visualization of the tissue is developed. The technique enables the radiologist to study normal structures as well as to detect tumors, fluid buildup, dead tissue, and other abnormalities. Formerly called computed (or computerized) axial tomography (CAT).


A tomographic method that employs a narrowly collimated beam of x rays to image the body in cross-sectional slices, (tomos comes from the Greek word for slice.) An array of detectors, positioned at several angles, records those x rays that pass through the body. Computers employing sophisticated mathematical algorithms can then reconstruct a two-dimensional image of internal bodily structures by analyzing the relative absorption or scattering of x rays for the different detector positions. Computed tomography is sometimes also referred to as computerized axial tomography or computer-assisted tomography, in which case the device used to produce the tomographic image is called a “CAT scanner.” The term computed tomography may also apply to forms of tomography using positrons or ultrasound for imaging instead of x rays.


An imaging technique carried out by using radiation (x-rays;) and analyzing and displaying the absorption (or transmission) of the radiation by the tissues. The key to this technology is a microcomputer within the machine. CT was formerly called “computed axial tomography” (CAT). The machine which creates the image is a CT (or CAT) scanner.


Tomography is an X-ray examination technique in which only structures in a particular plane produce clearly focused images. Whole-body computed tomography was introduced in 1977 and has already made a major impact in the investigation and management of medical and surgical disease. The technique is particularly valuable where a mass distorts the contour of an organ or where a lesion has a density different from that of surrounding tissue.


A computerized x-ray scanning system that produces a sectional anatomic image. It is achieved by digital processing of x-ray attenuation coefficients from a 360° wedge scan of ionizing radiation. There is considerable use of data from the attenuation coefficients in diagnosis.


 


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