Patent Number: 
Section: claims

1. An X-ray computed tomography apparatus comprising:an X-ray tube configured to generate X-rays;an X-ray detector configured to detect the X-rays generated from the X-ray tube and transmitted through an object;a top on which the object is placed;a rotation driving unit configured to rotate a rotating frame around the object, wherein the X-ray tube and the X-ray detector are mounted on the rotating frame;a movement driving unit configured to relatively reciprocate the rotating frame and the top over a plurality of times along a long-axis direction of the top; anda scan control unit configured to control the movement driving unit in relative reciprocal movement of the rotating frame and the top to coordinate a first plurality of moving loci of the X-ray tube with a first plurality of respective forward movements of at least one of the top and the rotating frame, and to coordinate a second plurality of moving loci of the X-ray tube with a second plurality of respective backward movements of at least one of the top and the rotating frame. 2. The X-ray computed tomography apparatus of claim 1, wherein the scan control unit is configured to determine velocity of the reciprocal movement based on imaging range information. 3. The X-ray computed tomography apparatus of claim 2, wherein the scan control unit is configured to determine acceleration of relative movement at a turnaround portion of the reciprocal movement based on the imaging range information. 4. The X-ray computed tomography apparatus of claim 3, wherein the scan control unit is configured to determine a time change pattern of acceleration based on an imaging range for the object. 5. The X-ray computed tomography apparatus of claim 2, wherein the scan control unit is configured to determine the velocity of the reciprocal movement in a constant-velocity interval based on the imaging range information. 6. The X-ray computed tomography apparatus of claim 2, wherein the scan control unit is configured to control the X-ray tube and the X-ray detector to generate the X-rays and acquire projection data in acceleration and deceleration intervals of a turnaround portion of the reciprocal movement.