1. A method for reconstructing a medical image of an object in a reconstruction process, comprising: collecting a real measured projection image data of said object with a medical imaging system; comparing a reconstructed projection image data to the real measured image data for determining a likelihood component; determining, in addition to the likelihood component, an antipriori component for modeling artifacts caused by detects in images caused by unidealities of the imaging system geometry tolerances or algorithm; and using said antipriori component for attenuating said artifacts from the collected real measured image data of said object to be reconstructed in real time in said reconstruction process; wherein the antipriori component is used for attenuating artifacts induced essentially by likelihood component.