1. A tomography apparatus comprising: a data acquirer configured to: acquire a first image corresponding to a first time point and a second image corresponding to a second time point, based on data that is obtained from performing tomography on a moving object; acquire first information indicating a movement of the object between the first time point and the second time point; and determine a motion reliability indicating a degree to which the movement of the object corresponds to a physical movement, based on the first information; and an image reconstructor configured to reconstruct a target image indicating the object at a target time point, based on the motion reliability.