Patent ID: 8873705

Claim:
An X-ray CT apparatus comprising: X-ray generation means configured to irradiate X-rays; an X-ray detector in which a plurality of detector modules, each of which includes X-ray detection elements that detect the X-rays and convert the X-rays into electric signals and that are aligned in a two-dimensional direction of a channel direction and a slice direction, are arrayed in the slice direction; signal processing means configured to generate projection data by performing signal processing on raw data acquired from the electric signals detected by the plurality of X-ray detection elements of the X-ray detector; and reconstruction processing means configured to generate a reconstruction image by performing reconstruction processing on the projection data, wherein each of the detector modules has reference positions at predetermined positions in the slice direction, in the detector modules, there is a gap between the detector modules adjacent to each other in the slice direction, and the signal processing means includes storage means configured to store the width of the gap in the slice direction as a gap value, position correction means configured to correct a slice position, which is specified by a position of the X-ray detection element of the X-ray detector, to a position set in advance between the reference positions set in two of the plurality of detector modules, and data estimation means configured to estimate a data output value at a slice position after correction by the position correction means from the gap value stored in the storage means and the raw data acquired from the electric signals detected by the X-ray detection elements and generates the projection data from the data output value estimated by the data estimation means.