A method and computer-readable medium for reconstructing an image volume of an object scanned in helical mode is provided. The method and computer-readable medium include obtaining one or more helical views corresponding to an image volume of an object and determining a plurality of discretized focal lengths within an imaging plane of the reconstructed field of view comprising the image volume. The method then comprises generating a plurality of circular scan sinograms for the plurality of discretized focal lengths. The plurality of circular scan sinograms are generated by interpolating the helical views. The method then comprises selecting one or more circular scan sinograms from the plurality of circular scan sinograms, based on the plurality of discretized focal lengths, wherein the selection is performed within a backprojection operation, for one or more image points within the imaging plane, over one or more circular views. The method then comprises using one or more of the selected circular scan sinograms, in the backprojection of one or more of the image points over one or more of the circular views. The method finally comprises performing a backprojection for all the image points over all the circular views to generate a reconstructed image of the object.