Patent ID: 7684539

Claim:
An X-ray tomograph comprising: a radiation source and a radiation detector arranged opposite to each other, between which a bed with an examinee placed thereon is provided, said radiation source and radiation detector turning around said bed which is configured to move with respect to a go-around axis, radiation irradiated from said radiation source and passing through the examinee being detected using said radiation detector and being converted to projection data; and reconfiguration means for creating a three-dimensional tomographic image in a region in concern of the examinee from the projection data, wherein said reconfiguration means determines, for each voxel, a projection data phase range as an angle between 180 and 360 degrees from projection data obtained at a spiral orbit scan so that a difference in absolute values of cone angles at both ends of the projection data phase range used is minimized, superimposes a reconfiguration filter, assigns weights to data of a same phase or opposite phase for each phase for the projection data phase range1 and three-dimension back projects the filter-processed projection data over said projection data phase range determined for each voxel along an irradiation trace of a radiation beam.