A radiographic imaging apparatus comprising: a radiation detector; a radiation source array having a plurality of radiation sources; a control processor (20, 430) configured to sequentially and separately energize a selected two or more of the plurality of radiation sources; a rotatable collimator having a plurality of apertures therethrough, the collimator being rotatable to either a first position or a second position to situate a plurality of the apertures in a path of radiation from energized ones of the plurality of radiation sources, wherein, when the collimator is at the first position, the plurality of apertures are aligned with a first subset of the radiation sources to define a first radiation field on the radiation detector, when the collimator is at the second position the plurality of apertures are aligned with a second subset of the radiation sources to define a second radiation field on the radiation detector; and a transport apparatus that is energizable to move the collimator between at least the first and the second positions; characterized in that the first and second subsets of the radiation sources are mutually exclusive and each subset includes half of the radiation sources, and wherein the first and second radiation fields are substantially the same; and each of the plurality of radiation sources that is blocked by the collimator from emitting x-rays toward a subject when the collimator is at the first position is adjacent to at least one radiation source of the plurality of radiation sources that is not blocked from emitting x-rays toward the subject when the collimator is at the first position. a radiation detector; a radiation source array having a plurality of radiation sources; a control processor (20, 430) configured to sequentially and separately energize a selected two or more of the plurality of radiation sources; a rotatable collimator having a plurality of apertures therethrough, the collimator being rotatable to either a first position or a second position to situate a plurality of the apertures in a path of radiation from energized ones of the plurality of radiation sources, wherein, when the collimator is at the first position, the plurality of apertures are aligned with a first subset of the radiation sources to define a first radiation field on the radiation detector, when the collimator is at the second position the plurality of apertures are aligned with a second subset of the radiation sources to define a second radiation field on the radiation detector; and a transport apparatus that is energizable to move the collimator between at least the first and the second positions; characterized in that the first and second subsets of the radiation sources are mutually exclusive and each subset includes half of the radiation sources, and wherein the first and second radiation fields are substantially the same; and each of the plurality of radiation sources that is blocked by the collimator from emitting x-rays toward a subject when the collimator is at the first position is adjacent to at least one radiation source of the plurality of radiation sources that is not blocked from emitting x-rays toward the subject when the collimator is at the first position.