A method and system for generating a field of view extension of a CT scan and minimizing the effect of interfering objects is described. The system is configured and the method carries out the steps of generating a full sinogram based upon CT scan data of a scanned object and any interfering objects within the scanning field; determining the location of any interfering objects within the CT data based on physical and geometrical properties of the interfering objects; generating an ideal sinogram of any interfering objects based on their location and physical properties; subtracting the ideal sinogram from the full sinogram; extending a sinogram free of any interfering objects; and adding the ideal sinogram of interfering objects to the extended sinogram of the scanned object. Speeding up the computation of the extended sinogram by creating a look-up table of the tunable parameter of the extension function.