Photon-counting detector calibration

A system, comprising:

• a calibration factor generator that determines a set of photon-counting calibration factors for photon-counting detector pixels of a spectral CT imaging system, wherein the calibration factor generator determines the set of photon-counting calibration factors based on counts for each detector pixel, energy bin, and thicknesses combination from data from a single scan, by the spectral CT imaging system, of a plurality of steps of a single phantom composed of a single material, where each step has a known and different approximately uniform thickness, and an analytical model that estimates counts for the same detector pixel, energy bin, and thicknesses combinations;
• a data corrector that corrects measured data from the photon-counting detector pixels of subject or object produced in response to a scan of the subject or object with the spectral CT imaging system based on the set of photon-counting calibration factors,
• a signal decomposer that spectrally decomposes the corrected measured data into two or more energy dependent components using the same analytical model.