1. A method for iteratively reconstructing an image acquired by a computed tomography (CT) system comprising: generating a calculated sinogram from an image estimate; generating an error sinogram based on the calculated sinogram and a measured sinogram; performing one or more backprojections each based upon a reconstruction parameter, wherein the reconstruction parameter impacts at least one of convergence speed and computational cost of each iterative step and corresponding reconstruction, and wherein a filtering step is performed prior to performing the one or more backprojections; and updating the image estimate by adding corresponding results of the one or more backprojections to the image estimate.