A method for automated sinogram completion, the method comprising the steps of: for each angle of a plurality of angles of a multi-angle scanning of a subject: (a) acquiring an initial projection corresponding to the angle, wherein the initial projection stores data representing signals from a first region of a detector during the multi-angle; (b) downsampling, by a processor of a computing device and to a reduced resolution, the initial projection acquired, thereby obtaining a downsampled projection having a resolution that is lower than that of the initial projection; (c) storing the downsampled projection as a projection of a downsampled sinogram; (d) cropping, by the processor, the initial projection to obtain a truncated projection, wherein the truncated projection stores data representing signals from a second region of the detection, wherein the second region of the detector is a subregion of the first region and smaller than the first region; and (e) storing the truncated projection as a projection of a truncated sinogram; (f) interpolating, by the processor, each projection of the downsampled sinogram based on a resolution of the truncated sinogram; and (g) determining and storing, by the processor, a combined projection, wherein the combined projection is based on a projection of the truncated sinogram and the interpolated projection, and wherein no more than one combined projection corresponding to each angle is stored for the angle, thereby resulting in a plurality of combined projections corresponding to the plurality of angles of the multi-angle scanning; and (h) creating, by the processor, a 3D image of the subject using the plurality of combined projections corresponding to the plurality of angles. (a) acquiring an initial projection corresponding to the angle, wherein the initial projection stores data representing signals from a first region of a detector during the multi-angle; (b) downsampling, by a processor of a computing device and to a reduced resolution, the initial projection acquired, thereby obtaining a downsampled projection having a resolution that is lower than that of the initial projection; (c) storing the downsampled projection as a projection of a downsampled sinogram; (d) cropping, by the processor, the initial projection to obtain a truncated projection, wherein the truncated projection stores data representing signals from a second region of the detection, wherein the second region of the detector is a subregion of the first region and smaller than the first region; and (e) storing the truncated projection as a projection of a truncated sinogram; (f) interpolating, by the processor, each projection of the downsampled sinogram based on a resolution of the truncated sinogram; and (g) determining and storing, by the processor, a combined projection, wherein the combined projection is based on a projection of the truncated sinogram and the interpolated projection, and wherein no more than one combined projection corresponding to each angle is stored for the angle, thereby resulting in a plurality of combined projections corresponding to the plurality of angles of the multi-angle scanning; and (h) creating, by the processor, a 3D image of the subject using the plurality of combined projections corresponding to the plurality of angles.