(The following, as well as the image itself, comes from the english wikipedia, uploaded by en:User:ChumpusRex)

A modern (2006) CT scanner with the cover removed, demonstrating the principle of operation. The X-ray tube and the detectors are mounted on a ring shaped gantry. The patient lies in the center of the gantry while the gantry rotates around them.

This arrangement, a broad fan-shaped X-ray beam with rotating source and detectors, is the 'third-generation' configuration.

This scanner is capable of helical scanning - the gantry is able to rotate freely while the patient moves continuously through the plane of the scan. Power (up to 100 kW) and data (up to 5 Gbps) are transferred to and from the gantry using slip rings (not shown).

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