Abstract: In order to obtain a tomographic image close to a stationary image using opposite view data, a radiation tomography method and apparatus are provided for measuring projection data representing a subject by radiation beams in a plurality of view directions around the subject; calculating estimated projection data for each of the plurality of view directions by performing a weighting calculation on data elements of the projection data generated by radiations which transmit through the same path in opposite directions so that a desired time phase for the subject is centrally weighted; and producing a tomographic image of the subject based on the estimated projection data.

Abstract: To make it possible to decrease an X-ray exposure on an operator and to obtain an image of high quality upon fluoroscopy operation an X-ray tube is rotated to acquire data, an X-ray radiation dose is set to "0" in a predetermined angular range including an angle at which the alignment of the X-ray tube with the operator's hand is brought about, and the X-ray radiation dose is set to an ordinary one at an angle in a range other than that angular range. The predetermined angular range is established using a light beam which enables to see what part of the field has no X-ray radiation exposure, thereby increasing his safety.

Abstract: A data processing technique for X-ray computerized tomography (CT) calculates the difference of two pieces of data having a same X-ray trajectory and existing on both sides of a plane of concern, and accumulates the differential value in a coordinate-correspondent buffer of respective xy coordinates on the X-ray trajectory. It repeats the operation for raw data of at least one turn on one side of the plane of concern, and stores the accumulative values in the buffers together with the z-axis position of the plane of concern. It repeats the operation while varying the z-axis position within a prescribed range on the plane of concern, and infers, based on the distribution along z-axis positions of the accumulative values in the buffers of same xy coordinates, the z-axis position of sharp varying plane of X-ray absorption coefficients relevant to the xy coordinates.