PROBLEM TO BE SOLVED: To restrict exposure of a patient to an X-ray while maintaining favorable quality of a reconstructed image in an X-ray CT apparatus.SOLUTION: The X-ray CD apparatus 10 comprises an irradiate unit irradiating an X-ray, a tube current value modulation determination unit 54 determinating a tube current value modulation to extend to a body axis direction in a predetermined rotation angle of the irradiate unit based on an index value to show a dispersion of CT values in required area in a reconstructed image, and a displaying unit 47 aligning and displaying an image of the index value and an image of the tube current value modulation on an image used for positioning.COPYRIGHT: (C)2010,JPO&INPIT【課題】X線CT装置において、再構成画像の画質を好適に維持しつつ、患者のX線被曝を抑制すること。【解決手段】X線CT装置10は、X線を照射する照射手段と、再構成画像内の所要領域内のCT値のばらつきを表し前記照射手段の1回転毎の指標値とスキャン条件とを基に、体軸方向の管電流値変調を決定する管電流値変調決定部54と、位置決め用画像上に、前記指標値及び前記管電流値変調を位置合わせして表示する表示装置47と、を有する。【選択図】 図2
