1. A method for reconstructing an x-ray image of an object under examination from measured projection data indicative of the object, comprising: converting the measured projection data into image data; regularizing the image data to generate regularized image data, comprising modifying one or more specified quality metrics in the image data; forward projecting the regularized image data to generate synthesized projection data; and updating the image data to generate updated image data comprising comparing the synthesized projection data to the measured projection data.