PROBLEM TO BE SOLVED: To reduce an X-ray exposure dose as much as possible in measuring the timing for injecting a contrast medium of a required concentration into a desired region of a subject in the contrast examination.SOLUTION: The X-ray CT apparatus includes: an X-ray source for irradiating the subject with X-rays an X-ray detector disposed opposite from the X-ray source for detecting X-rays transmitted through the subject a rotary disk on which the X-ray source and the X-ray detector are mounted to rotate around the subject an image reconstruction device for reconstructing tomographic images of the subject based on the transmitted X-ray dose detected by the X-ray detector an image display device for displaying the tomographic images reconstructed by the image reconstruction device a contrast medium administration means for administering the contrast medium into the subject and a control part for controlling the respective components. The control part measures the timing when the concentration of the contrast medium becomes a desired value in the desired region of the subject based on the transmitted X-ray dose detected by the X-ray detector and controls a main scan to be executed at the measured timing.COPYRIGHT: (C)2011,JPO&INPIT【課題】 造影検査において、被検体の所望の部位に造影剤が所望の濃度注入されるタイミングを計る際に、X線被ばく線量を可能な限り低減させる。【解決手段】 被検体にX線を照射するX線源と、前記X線源に対向配置され前記被検体を透過したX線を検出するX線検出器と、前記X線源と前記X線検出器を搭載し前記被検体の周囲を回転する回転円盤と、前記X線検出器により検出された透過X線量に基づき被検体の断層画像を再構成する画像再構成装置と、前記画像再構成装置により再構成された断層画像を表示する画像表示装置と、造影剤を前記被検体に投与する造影剤投与手段と、前記各構成要素を制御する制御部を備えたX線CT装置であって、前記制御部は、前記被検体の所望の部位において、前記造影剤が所望の濃度となるタイミングを、前記X線検出器により検出される前記透過X線量に基づき計り、該タイミングにおいて本スキャンを行うよう制御する。【選択図】 図1
