Beam hardening correction method for cone-beam computed tomography based on registered model simulation

According to the principle of beam hardening in cone-beam computed tomography (CBCT), a new beam hardening correction method for CBCT based on the union of practical projection and simulating projection was presented. In the method, a set of points was extracted from the serial slice images of the part that reconstructed beforehand firstly, and then the points and the CAD model were registered by initial registration and accuracy registration which were combined. After that, the length of X-ray traversing part on each imaging pixel was computed with simulation of registered CAD model. Finally, a new exponential function was designed for fitting the length-gray curve and made use of correcting beam hardening artifact. The experimental correction results of both simulation and practical scan show that the method can mostly remove the beam hardening artifact simply and practically.