Patent ID: 6987828

Claim:
A system comprising: an X-ray tube; data acquiring means for rotating an X-ray irradiating/detecting device, which includes an X-ray irradiator that has said X-ray tube and irradiates a fan-shaped X-ray beam and an X-ray detector that has a plurality of X-ray detecting elements arrayed in a direction in which the fan-shaped X-ray beam spreads and that is opposed to said X-ray irradiator with an object of imaging between them, about the object so as to acquire transmitted X-ray data stemming from a plurality of views; dose adjusting means for differentiating dose values of the X-ray beam between predetermined angular ranges of a section of the object shaped like an oval, which extend with the minor axis of the section as a centerline, and the other angular ranges thereof; and dose calculating means for calculating the dose values based on a specific target value of a standard deviation of an image, the standard deviation input independent of a reference value of a tube current designated to flow through said X-ray tube.