1. An apparatus, comprising: circuitry configured to obtain a plurality of projection datasets, wherein each projection dataset is obtained from a different detector type or different detector configuration; and reconstruct, from the respective plurality of projection datasets, a corresponding plurality of images using a combined image reconstruction, wherein the combined image reconstruction increases a spatial correlation among the images of the plurality of images relative to if each the plurality of images had been separately reconstructed, thereby to improve an image quality of the plurality of images.