Abstract: With the apparatus of CT, if the object contains a foreign body having high spatial frequency component such as a polygonal body etc., and large density difference from another region, a radial artifact is generated from a corner part of the side.The first object of the present invention is to provide an apparatus of CT to reduce artifacts without lowering of spatial resolving power.The second object of the present invention is to provide an apparatus of CT to reduce artifacts without increasing scanning time so much.The objects described above are achieved by the present invention with a method to disperse penetration data to surroundings when a sudden changing part of penetration data in translational data is detected in collecting penetration data from every direction for reconstruction of an image.

Abstract: To provide an improved holographic operation, a digital type ultrasonic holography apparatus is provided utilizing a clock pulse generator having a predetermined periodicity, an ultrasonic pulse beam generator for directing an ultrasonic beam to an object for measurement in synchronism with said clock pulse, a reflected wave conversion unit for converting reflected ultrasonic pulse beams from said object for measurement into digital pulses, a time coincidence detector for detecting time coincidence between said clock pulse and said digital pulses contained in a predetermined gate period and producing as output a coincidence signal when they coincide with each other, a unit for moving an ultrasonic generating and receiving transducer included in said ultrasonic pulse beam generator to a desired position, and a display device for displaying the hologram of said object for measurement using said coincidence signal as a luminance signal and a position signal of said ultrasonic generating and receiving transducer