1. An image processing apparatus comprising: a scatter simulation processor which processes measured sinograms generated from imaging data acquired for an imaging subject by an imaging apparatus to produce a scatter sinogram that represents a shape of scatter contribution; a scatter scaling processor utilizing a Monte Carlo simulation to determine a scatter fraction and scales the scatter sinogram to generate a scaled scatter sinogram that matches the scatter contribution in the measured sinogram; and a reconstruction processor which reconstructs the imaging data into an image representation using the scaled scatter sinogram for scatter correction,