PROBLEM TO BE SOLVED: To reduce shielding of radiated X-rays due to photon counting detectors.SOLUTION: An X-ray CT apparatus includes an X-ray source and photon counting type detectors. The X-ray source rotates around a bed on which a subject is placed, and radiates X-rays. The photon counting type detectors count X-ray photons and are arranged in a plurality number along the rotational direction of the X-ray source. The longitudinal direction of the detectors turns to a position not superimposed on paths of the X-rays when the X-ray source approaches within a prescribed distance.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2017,JPO&INPIT【課題】光子計数型検出器による放射X線の遮蔽を低減させること。【解決手段】実施形態のX線CT装置は、X線源と、光子計数型検出器とを備える。X線源は、被検体が載置される寝台の周りを回転し、X線を放射する。光子計数型検出器は、前記X線の光子を計数し、前記X線源の回転方向に沿って複数配置される光子計数型検出器であって、前記X線源が所定距離以内に近づいた場合に、前記X線の経路に重ならない位置を中心に、長手方向が前記X線の放射方向に回転する。【選択図】図1
