Patent ID: 6876720

Claim:
An X-ray computed tomography apparatus which monitors a density of a contrast medium injected into a subject to be examined with a CT value or a value derived therefrom by repeated preparation scans so as to adjust a main scan start timing that differs in scan condition from the preparation scans, comprising: a guidance output unit configured to output guidance to the subject; and a control unit configured to compare a CT value of each tomographic image obtained by the preparation scans or a value derived therefrom with a first threshold, supply guidance data to the guidance output unit or control the guidance output unit to output the guidance to the subject when the CT value or the value derived therefrom has reached the first threshold, compare the CT value of each tomographic image obtained by the preparation scans or the value derived therefrom with a second threshold different from the first threshold, and start executing the main scan or preparing the execution of the main scan when the CT value or the value derived therefrom has reached the second threshold.