Patent ID: 7145982

Claim:
An X-ray computer tomography apparatus, comprising: an X-ray source configured to irradiate X-rays onto an object to be examined; an X-ray detection unit configured to detect X-rays transmitted through the object; a driving unit configured to rotate at least one of the X-ray source and the X-ray detection unit around the object; an image data generation unit configured to generate image data on the basis of projection data using the X-ray detection unit; a density calculating unit configured to calculate contrast medium density in a region of interest being set in the image data from the image data generation unit after injecting contrast medium into the object; an irradiation condition setting unit configured to set a first irradiation condition for first scanning under which low-dose X-rays are irradiated, a second irradiation condition for second scanning under which high-dose X-rays are irradiated, and a third irradiation condition for a third scanning under which low-dose X-rays are irradiated on the basis of the contrast medium density; and a blood-flow information calculating unit configured to calculate blood-flow information on the basis of the image data obtained by the first scanning, the second scanning, and the third scanning.