A radiographic imaging apparatus comprising: a radiation detector ; a radiation source array having a plurality of radiation sources ; a control processor 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 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. <EOS>