Disclosed are a radiation imaging apparatus , a computed tomography apparatus, and a radiation imaging method using the same. The radiation imaging apparatus includes a radiation emitter configured to emit radiation to an object while moving around the object, a radiation detector configured to detect radiation emitted from the radiation emitter and to change the detected radiation into an electric signal to thereby store the electric signal , and an irradiation controller to control the radiation emitter such that radiation is emitted to the object in at least one position or zone around the object and such that the radiation emitter stops emission of radiation to the object in a position or zone corresponding to the at least one position or zone.
