1. A method for operating an X-ray Computed Tomography (CT) scanning device, the method comprising: acquiring, by the CT scanning device, a plurality of images of an object; obtaining an initial image from the plurality of images; performing a calculation of NonLocal (NL) weight utilizing a current image estimation and a registered prior image; performing a Successive Over-Relaxation (SOR) optimization to yield a new image estimation, with an intensity of the new image estimation being equal or greater than zero; performing a cycle update that repeats the obtaining of the initial image, the performing of the NL weight calculation, and the SOR optimization; generating an image of the object utilizing the new image estimation obtained from the SOR optimization; and outputting a resultant image when a stop criterion is met.