PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus which reduces operation time required for reducing artifacts caused by a high absorber component and shows excellent quantitative performance for a CT value.SOLUTION: The X-ray CT apparatus is equipped with: a re-projection means 320 which performs re-projection computation on an X-ray CT image of a subject containing the high absorber components based on a re-projection coefficient corresponding to the high absorber component and generates re-projection data of the high absorber components and a high absorber correcting means 300 which generates projection data of the high absorber component and projection data of substance components excluding the high absorber components based on the re-projection data and the projection data of the subject and performs a correction on each projection data separated by the substance component to reduce the artifacts which attribute to beam hardening of X rays. Reconstruction computation is performed based on the projection data of the high absorber component and the projection data of the substance components after the correction, and an X-ray CT image in which the artifacts are corrected is created.COPYRIGHT: (C)2010,JPO&INPIT【課題】高吸収体成分アーチファクトの低減に要する演算時間を短くし、かつCT値定量性に優れたX線CT装置を提供する。【解決手段】高吸収体成分を含む被検体のX線CT像を前記高吸収体成分に対応させた再投影係数に基づいて再投影演算をして、高吸収体成分の再投影データを生成する再投影手段320と、前記再投影データと前記被検体の投影データとに基づいて、前記高吸収体成分の投影データと前記高吸収体成分を除く物質成分の投影データとを生成し、それらの物質成分別の投影データの各々に対してX線の線質硬化に起因するアーチファクトを低減するための補正を施す高吸収体補正手段300と、を備え、補正後の前記高吸収体成分の投影データと前記物質成分の投影データとに基づいて再構成演算を行い、前記アーチファクトを補正したX線CT像を生成する。【選択図】図1
