Multiplexing signal processing channels in a CT scanner with rotating source

Claim 1

In a CT scanner having an array of stationary radiation detectors spaced in a curved path about a center point and having a concentrically rotating source of radiation emitted in a fan pattern subtending a number of the detectors, each detector producing an electronic output signal having an amplitude indicative of the intensity of radiation impinging upon that detector, the irradiated area common to different positions of the fan pattern defining a corresponding patient scan circle, a data channel multiplexing system which comprises: (a) a number of signal collecting means corresponding to at least the maximum number of detectors subtended by the fan pattern, each such signal collecting means connected to receive the electronic output signals of a respective exclusive group of nonconsecutive detectors, one and only one of which is irradiated at any given time by the radiation fan, for passing the electronic output signal at one time of no more than one detector in each group, the output of each said collecting means defining a corresponding signal processing channel; (b) a plurality of deactivating means each associated with a grouping of one or more detectors, for normally deactivating the output signal of each detector in said group; and (c) means, rotatable about said patient scan circle in fixed relation with said rotating source of radiation, for temporarily interrupting the deactivation means associated with a number of groups of adjacent detectors corresponding generally to the detectors subtended by the fan pattern to permit coupling to said signal collecting means the outputs of those adjacent detectors which at any time are subtended by said fan beam of radiation.