Beam Attenuation Grid–Based Scatter Correction Algorithm for Cone Beam Volume CT

In the flat panel detector-based cone beam CT system, the scatter photons which reach the flat panel detector increase the detected signal, produce the image cupping artifact and reduce the image contrast. To conquer the X-Ray scatter problem, this study proposes the beam attenuation grid -based scatter correction algorithm that needs to add a beam attenuation grid (BAG) between the X-Ray source and the test object. This paper mainly describes the beam attenuation grid device and the beam attenuation grid –based scatter correction algorithm. We also introduce some image quality assessments which can evaluate the effect of the scatter correction method. The cupping degree and the image contrast degree are evaluated with the cylinder sample and the lantern ring sample, respectively. The results indicate that this method work well for the cone beam CT system. It can effectively reduce the cupping artifact and increase the image contrast of the reconstruction slice image.