A method, system, and computer-readable medium that can resolve continuous and/or relatively rapid changes with time of a volume V without deterioration in image quality. In one embodiment of this invention, a subset of the projection data collected along a continuous circular orbit is combined with projection data collected along a different orbit to reconstruct the volume V substantially as it was when the subset of the projection data was collected. In one embodiment, the different orbit is a linear or a helical orbit. Further, staggered subsets of the projection data collected along a continuous circular orbit can also be used, as can further projection data collected along a linear orbit to resolve continuous and/or relatively rapid changes of a volume V.
