Uniformity correction in photon-counting X-ray detector based on basis material decomposition

We have developed and evaluated a method to correct for detector cell response variations in photon-counting X-ray detectors with energy discrimination capability. With these detectors, variations in energy thresholds or energy response of the detector cells can result in spectral-dependent non-uniformities in sinograms that produce rings in reconstructed images. The proposed method is basis material decomposition-based and corrects variations in the spectral sensitivity of detector cells to reflect the characteristics of a standard detector cell. It requires calibration similar to that used in basis material decomposition methods and does not require knowledge of the exact energy spectrum, energy thresholds, or energy response of the individual detector cells. Both simulation and physical experiments studies showed substantial reduction in non-uniformity in sinograms and of rings in reconstructed images.