An improved scattering correction method for model analysis of cone-beam CT

Due to the increased area of X-ray interaction with the objects, the cone beam computed tomography (CBCT) systems will bring severe scattering artifacts in reconstructed images, and the correction of which is quite essential to a good image quality. The scatter process modeling methods without Monte Carlo simulation proposed in recent years is relatively efficient to obtain the scattering distribution. In this paper, combined with Compton scattering cross section (K-N) formula, an improved scatter correction method is proposed for single-material objects. After setting the scattering points in the object from the reconstruction image, it is derived that the scattering ratio of any two scattering points at scattering angle 0 ° is approximately equal to the projection ratio of the object on the corresponding path of two scattering points. Therefore, the first-order Compton scattering values of all scattering points at scattering angle 0 ° can be calculated. The scattering probability of the same scattering point at different scattering angles are then normalized to obtain the scattering ratio. The scattering distribution of each scattering point was calculated by combining the scattering value at 0 ° and the included angle and distance between the scattering point and the detector. Since the attenuation coefficient selection and the attenuation path length calculation before the scattering points are omitted, the scattering estimation error is reduced, and the scattering estimation efficiency is improved. The experimental correction results for the CT images of the aircraft aluminum castings show that the proposed method can effectively restore the structural information of scattering effects, enhancing the contrast to noise ratio (CNR) and reducing the cup shadow from 9.07% to 5.49%.