Patent ID: 8126109

Claim:
An X-ray CT apparatus comprising: an imaging unit configured to irradiate a subject, switching scanning conditions, with X-rays continuously or intermittently, and to reconstruct an image by detecting X-rays passed through the subject; an index-value detecting unit configured to detect an index value that indicates a contrast medium density in the image reconstructed by the imaging unit during a scan; a switch-timing detecting unit configured to detect switch timing of the scanning conditions based on the index value detected by the index-value detecting unit; and an imaging control unit configured to control the imaging unit so as to perform a prep scan and a main scan, the main scan including a first scan with a first scanning condition and a second scan with a second scanning condition; wherein the imaging control unit controls, during the prep scan, the imaging unit so as to start the main scan with a timing when the index value exceeds a threshold value, and controls, during the main scan, the imaging unit so as to skip a rest of the first scan in execution and to start the second scan upon detecting the switch timing by the switch-timing detecting unit.