PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus, wherein tomography is applied for each of subjects with an optimum dose of X-ray by automatically controlling starting/finishing a tomographic plan, corresponding to the density of a contrast medium during tomography.SOLUTION: In a system control unit 38 for totally controlling the X-ray CT apparatus, an index-value detecting unit 38a detects an index value that indicates a contrast medium density in a region of interest (ROI) set on an image reconstructed during tomography. A switch-timing detecting unit 38b detects an inflection point appearing on a curve that indicates temporal variations in the contrast medium density in the ROI, based on an index value detected by the index-value detecting unit 38a. An imaging control unit 38d then performs control so as to skip the rest of a scanning plan in execution and to start the next scanning plan when the switch-timing detecting unit 38b detects an inflection point.COPYRIGHT: (C)2009,JPO&INPIT【課題】X線CT装置において、撮影中に造影剤の濃度に応じて自動的に撮影プランの開始/終了を制御して、被検体ごとに最適なX線の線量で撮影を行う。【解決手段】X線CT装置の全体制御を行うシステム制御部38において、指標値検出部38aが、撮影中に再構成される画像に設定されたROI内の造影剤濃度を示す指標値を検出し、切替時機検出部38bが、指標値検出部38aによって検出される指標値に基づいて、ROI内の造影剤濃度の経時的な変化を表す曲線に生じる変曲点を検出し、撮影制御部38dが、切替時機検出部38bによって変曲点が検出された場合に、実施中の撮影プランの残りを中止して次の撮影プランを開始するよう制御する。【選択図】 図2
