Radiation tomographic imaging apparatus and method

A radiation tomographic imaging apparatus and method are provided in which the slice thickness can be dynamically switched during scanning, and the emission center of radiation can be arbitrarily moved in a direction of carrying a subject. There are provided an X-ray tube moving section 21 capable of moving the emission center of an X-ray tube 20 in a z-direction; a collimator 22 having an aperture whose openness can be adjusted, for forming the emitted X-rays into an X-ray beam 5 having a certain width and thickness to irradiate a desired region on a detector element array 23 with the X-ray beam 5 ; a data collecting section 24 for dynamically selecting or adding in varying combination the detected signal input supplied from the detector element rows in the detector element array 23 during scanning in response to a control signal CTL 303 ; and a central processing apparatus 30 for changing the emission center of the X-ray tube 20 , the openness of the aperture in the collimator 22 , and the data to be collected by the data collecting section 24 corresponding to status information input via an input device 31.