PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus reducing image artifact caused by the focal movement of an X-ray tube device due to thermal expansion or the like, and correcting a focal position resulting from the exchange of X-ray tube devices, by a simple mechanism.SOLUTION: This X-ray CT apparatus includes: an X-ray tube having a rotary anode which generates X-ray beams by collision of electron beams, with a collision position defined as an X-ray focal point an X-ray detector disposed to face the X-ray tube a collimator disposed on the X-ray beam radiation surface side of the X-ray tube and restricting the radiation range of the X-ray beam. The collimator has a pair of shielding plates which are disposed in parallel and restrict the radiation range of the X-ray beam at least in the rotation central axis direction of the rotary anode, a first adjusting mechanism which controls the interval between the pair of shielding plates to adjust the radiation range of the X-ray beam, and a second adjusting mechanism which adjusts the positions of the pair of shielding plates in the rotation axis direction of the rotary anode, while keeping the interval of the pair of shielding plates.COPYRIGHT: (C)2011,JPO&INPIT【課題】熱膨張等によるX線管装置の焦点移動に起因した画像アーチファクトの低減と、X線管装置の交換に伴う焦点位置の補正とを簡易な機構で行うことが可能なX線CT装置を提供することである。【解決手段】電子ビームの衝突により該衝突位置をX線焦点としたX線ビームを発生する回転陽極を有するX線管と、前記X線管と対向配置されるX線検出器と、前記X線管のX線ビーム照射面側に配置され、前記X線ビームの照射範囲を制限するコリメータとを備えるX線CT装置であって、前記コリメータは、前記X線ビームの照射範囲を少なくとも前記回転陽極の回転中心軸方向に制限する一対の平行配置された遮蔽板を有し、前記一対の遮蔽板の間隔を制御し、前記X線ビームの照射範囲を調整させる第1の調整機構と、前記一対の遮蔽板の間隔を保持した状態で、該一対の遮蔽板の位置を前記回転陽極の回転中心軸方向に調整する第2の調整機構とを備えるX線CT装置である。【選択図】 図2
