A method of obtaining a volumetric image includes obtaining a plurality of volumetric images, the volumetric images generated using respective sets of projection images, wherein the volumetric images and the respective sets of projection images correspond with different respective bins for a physiological cycle, and determining an additional volumetric image using one or more of the projection images from each of the sets that correspond with the different respective bins for the physiological cycle, wherein the act of determining the additional volumetric image is performed using a processor.