Abstract: In a state where a subject 5 is not present, a pre-processing unit 7 changes the focal spot position that becomes the position of an X-ray tube 2, acquires the X-ray incidence rate of each detection module at each focal spot position, approximates the X-ray incidence rate of each detection module by the X-ray incidence rate of a module in which a reference detector is present, and stores the coefficient of an approximate polynomial in a storage unit 8. When a scanning of the subject 5 is performed, the X-ray incidence rate of each detection module is calculated using the X-ray incidence rate of the module in which the reference detector is present and the stored coefficient, and sensitivity correction data relating to each focal spot position is obtained using the calculated X-ray incidence rate when the scanning of the subject is performed.

Abstract: The radiation imaging device acquires incident position information of radiation for each detector by setting the size of a through-hole such that at least one pixel is arrayed in a plane view from a direction perpendicular to the detector plane; arranges a septa in displacing from a boundary line between a detector pair in a plane view from a direction perpendicular to the detector plane; further arranging the septa so as to be orthogonal to the boundary line between the detector pair in a plane view from a direction perpendicular to the detector plane; arranges the top of the through-hole in a plane view from a direction perpendicular to the detector plane, in displacing from the boundary line of the detector pair; and arranges the top of the detectors in a plane view from a direction perpendicular to the detector plane so as to be visible through the through-hole.

Abstract: In a state where a subject 5 is not present, a pre-processing unit 7 changes the focal spot position that becomes the position of an X-ray tube 2, acquires the X-ray incidence rate of each detection module at each focal spot position, approximates the X-ray incidence rate of each detection module by the X-ray incidence rate of a module in which a reference detector is present, and stores the coefficient of an approximate polynomial in a storage unit 8. When a scanning of the subject 5 is performed, the X-ray incidence rate of each detection module is calculated using the X-ray incidence rate of the module in which the reference detector is present and the stored coefficient, and sensitivity correction data relating to each focal spot position is obtained using the calculated X-ray incidence rate when the scanning of the subject is performed.

Abstract: Scattered X-rays scattered by an object or a structure enter in a detector (a shift detector) for detecting the positional shift of an X-ray focal point and become a noise source, thereby deteriorating the positional shift detection precision. In particular, the estimation of the dose of scattered X-rays originating from the object is difficult prior to the measurement, and correction of the scattered X-rays is important in order to precisely calculate the positional shift of the X-ray focal point. In order to address this drawback, according to the present invention, a scattered X-ray detector 6 is provided which measures the dose of scattered rays entering in a shift detector 5 for detecting the positional shift of an X-ray focal point 9, and has a function that the output by the shift detector 5 is corrected using the scattered ray dose measured by the scattered X-ray detector.