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How does a CT scanner create cross-sectional images of the body?

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Diagram of the electromagnetic spectrum showing different types of waves arranged by wavelength and frequency, from gamma rays and X-rays to ultraviolet, visible light, infrared, microwave, TV/FM radio, shortwave radio, AM radio, and longwave radio. — X-ray The relationship of X-rays to other electromagnetic radiation within the electromagnetic spectrum.

A CT scanner creates detailed cross-sectional images by using a narrow beam of X-rays that rotates around the patient at many different angles.12

Unlike conventional X-ray systems, which project all structures in the beam's path onto a single image, a computed tomography (CT) scanner utilizes a series of radiation detectors to measure the strength of the X-ray photons as they pass through the body. These detectors record the data as a pattern of electrical impulses rather than on film.32

A computer then integrates and processes these absorption figures to assess the density of tissues at thousands of points. By reconstructing this data, the system produces a two-dimensional, cross-sectional image on a monitor, allowing for the precise visualization of internal structures, tumours, and other abnormalities that might otherwise be obscured by overlying tissues.321