1. A statistical iterative image reconstruction method for use in computed tomography (CT), the method comprising: generating an image; generating a set of calculated measurements based on the image; generating a set of actual measurements derived from a set of CT image data; comparing a measured sinogram derived from the set of actual measurements and a calculated sinogram derived from the set of calculated measurements to determine whether a completion criterion is satisfied; if the completion criterion is satisfied, providing the image as a final image; if the completion criterion is not satisfied, generating an image update of the image, applying a ramp filter or a square root of the ramp filter to one or both of the image or the image update, and repeating the steps of generating the set of calculated measurements and determining whether the completion criterion is satisfied based on the image after application of the image update.