CT IMAGE CORRECTION FOR BEAM HARDENING USING SIMULATED PROJECTION DATA

A general beam-hardening correction technique is presented. Knowledge of the CT scanner X-ray spectrum is necessary. This postreconstruction method does not require the original projection data. Simulated projections through an uncorrected reconstructed image are used to correct for beam hardening. Errors in the mean linear attenuation coefficient are decreased from 30% to 5% with virtual elimination of the visual streaking artifact. The theoretical image improvement equals that of projection linearization postreconstruction methods using the original projection data. The correction is limited to cases where the material causing the beam hardening is contained within the reconstruction space. © 1990 IEEE