Spatial resolution improvement of 450 kV computed tomography via vertical subpixel detector shifting.

Abstract

X-ray sources with acceleration voltages of 450 kV typically have large focal spot sizes that lead to low spatial resolution computed tomography (CT) data. In this work a method to improve the spatial resolution of 450 kV CT is developed. The proposed method relies on using vertical subpixel detector shifting and deconvolution to generate a projection-set that has double the number of pixels in the direction parallel to the axis of rotation. The results show that the proposed method is able to increase the 10% modulation transfer function of the considered system from 3 lp/mm to 4 lp/mm. In addition, a scan of a metal additively manufactured component with periodic features of approximately 200 μm is used to demonstrate the method; small features that were not fully resolved in a conventional scan become resolvable when the proposed method is used.