Patent ID: 7792242

Claim:
An X-ray CT system, comprising: a rotary stage which is arranged between an X-ray source and an X-ray detector which are arranged opposite to each other and rotates around a rotational axis orthogonal to an X-ray optical axis while holding a subject; a reconstruction computing section for reconstructing a tomogram of the subject along a plane orthogonal to the rotational axis, by using X-ray transmission data of the subject that is obtained for every predetermined angle while the rotary stage is being rotated; an optical camera which captures the subject on the rotary stage from a position along the rotational axis of the rotary stage or a position close to the rotational axis; an image processing section which acquires information related to shape, size and a position relative to the rotational axis, of the subject, from an external image of the subject captured by the optical camera; an interference monitoring section which monitors an interference between the subject and the X-ray source during rotation of the rotary stage by using the information acquired by the image processing section; a CT projection area computing section for calculating an area where CT projection is available around the rotational axis as a center, by using information about a positional relationship among the X-ray source, the X-ray detector and the rotary stage in a direction of the X-ray optical axis, and a size of a light-receiving surface of the X-ray detector; and a display section which superimposes the area calculated by the CT projection area computing section on an image of the subject captured by the optical camera so as to display the image on a display.