PROBLEM TO BE SOLVED: To realize an X-ray CT apparatus which facilitates beam hardening correction.SOLUTION: The X-ray CT apparatus has a photographing part which reconstructs images from projection data acquired by scanning the site of a subject set via a scout photographing with X rays and a control part which controls the operation involved. The control part works to determine the attenuation of transmission X rays at a location subject to photographing from the result of the scout photographing and causes changes in the X-ray beam quality during the scanning operation according to the variance of the attenuation. The changes in the X-ray beam quality are made by increasing or decreasing the tube voltage of an X-ray tube.COPYRIGHT: (C)2008,JPO&INPIT【課題】ビームハードニング補正が容易なX線CT装置を実現する。【解決手段】X線CT装置は、スカウト撮影を経て設定された被検体の撮影箇所をX線でスキャンして得られる投影データに基づいて画像再構成を行う撮影部とそれを制御する制御部を有し、前記制御部は、前記スカウト撮影の結果から撮影予定箇所における透過X線の減衰量を求めさせ、前記減衰量の大小に応じてスキャン遂行中にX線ビーム線質を変化させる。前記X線ビーム線質の変化をX線管の管電圧の増減によって行わせる。【選択図】図9
