X-ray computerized tomograph

Claim 1

In an X-ray CT comprising a multi-channel detector for detecting a fan beam X-ray which is transmitted through a body under test; and a data acquisition device for acquiring view data based on an output signal from said multi-channel detector; the improvement comprising means for removing artifacts in a reconstructed image caused by instantaneous changes in strength of the X-ray, said means comprising watching means for watching the instantaneous strength of output from an X-ray source directly or indirectly; variation detecting means for detecting an abnormal variation in the instantaneous strength of the output from said X-ray source, by comparing an output signal from said watching means with a reference value; correction means comprising buffer memory means for storing output data from said data acquisition device corresponding to a plurality of views, and weighted averaging means for forming corrected view data by weighted averaging said data corresponding to a plurality of views stored in said buffer memory means, said correction means under control of an output signal from said variation detecting means for producing output data obtained from said data acquisition device, without any change, when the output data from said variation detecting means does not represent an abnormal variation in the instantaneous strength of the output from said X-ray source, and for producing output data which is corrected by weighted averaging of data stored in said buffer memory means corresponding to a plurality of views, when the output signal from said variation detecting means represents an abnormal variation in the instantaneous strength of the output from said X-ray source; and reconstruction means for receiving view data from said correction means, and for extracting parallel beam data from fan beam data, thereby carrying out image reconstruction for a parallel beam with artifacts due to instantaneous changes in the strength of X-rays being removed.