X-Ray Filtration, Noise And Artifacts In Computerized Tomography

The reduction of spectral artifacts in computerized tomography by X-ray tube filtration is studied. Due to quantum limited nature of the imaging system a reduction in exposure with filtration is followed by an increase of noise in the images. A combination of x-ray filtration and water table monochromatization is shown to work extremely well. A figure of merit which reflects the complex interplay of exposure, noise, contrast and spectral artifacts, is defined. The figure of merit is used in the determination of best filters to optimize some of the image quality parameters of the polychromatic CT images.