Patent ID: 7555096

Claim:
An X-ray image taking apparatus comprising: an X-ray source generating a fan beam of X-rays; an X-ray detecting apparatus having a plurality of channels and receiving the fan beam of X-rays; a rotating table on which a subject is mounted, for rotating the subject about a rotation center; a first storing unit which stores a first time-series value of penetrated data output for a fan angle α (alpha) from at least one of the plurality of channels, while the rotating table rotates through an angle γ (gamma); a second storing unit which stores other time-series values of penetrated data each of which is output from each of the plurality of channels, while the rotating table rotates through an angle γ (gamma) from a state at which the rotating table has rotated 180+2α degrees from a condition when the storage of the first time-series value of penetrated data is started; calculating means which calculates a difference between the first time-series value and the other time-series value of penetrated data output from each of the plurality of channels; channel selecting means which selects a channel outputting the other time series value corresponding to the least difference; and deviation providing means which provides as a position deviation between the rotation center of the rotating table and a center axis of the fan beam, half a difference between a position of the selected channel selected by the channel selecting means and a position of the channel outputting the first time-series value.