PROBLEM TO BE SOLVED: To efficiently collect, when a plurality of examinations are collectively performed by a set of synchronous electrocardiographic imaging in an X-ray CT apparatus, projection data needed for each examination while reducing the exposure to a subject to reconstruct necessary images.SOLUTION: A CT value of image in a region of interest is calculated with time. A half reconstruction is used as a reconstruction method in reconstruction of image from projection data while the calculated CT value does not exceed a prescribed threshold, and a segment reconstruction is used as the reconstruction method while the calculated CT value exceeds the prescribed threshold.COPYRIGHT: (C)2013,JPO&INPIT【課題】X線CT装置において、複数の検査が一連の心電同期撮影でまとめて行われる場合に、被検体への被ばく量を抑えながら各検査で必要な投影データを効率よく収集して、必要な画像を再構成する。【解決手段】関心領域内の画像のCT値を経時的に算出し、算出したCT値が所定の閾値を超えていない間は、投影データから画像が再構成される際の再構成方式をハーフ再構成とし、一方、算出したCT値が所定の閾値を超えている間は、再構成方式をセグメント再構成とする。【選択図】図1
