Correction of geometric artifacts on cone-beam CT system

Computer tomography (CT) image geometric artifacts are a kind of the pseudo-image not existing in the detected object, which could result in a serious degradation of image quality. Geometric artifacts are imported by the discrepancies between the geometric structure of cone-beam CT and the ideal structure of reconstruction algorithm. Analyzing the FDK algorithm, there are seven parameters that describe the irregular cone-beam structure. These parameters can be calculated by the calibration phantom´s projections, using related methods. And geometric calibration can be implemented in two ways: interpolation and modification of original FDK formula. At last, this method is applied on the Micro-CT system of our laboratory and proved to be effective for the correction of the geometric artifacts.