Count-weighted least squares parameter estimation for a photon-counting detector

A device for determining an optimal parameter vector, the parameter vector including a plurality of parameters of a detector response model of a photon-counting detector, the device comprising:

• a processing circuit configured to
• determine a normalized measured photon count for each energy bin of the photon-counting detector;
• set an initial incident photon spectrum and an initial value for each parameter of the plurality of parameters;
• calculate using the detector response model, a normalized modeled photon count for each energy bin of the photon-counting detector, based on the incident photon spectrum and the plurality of parameters;
• compute, for each energy bin, a square of a difference between the normalized measured photon count and the normalized modeled photon count;
• weight the computed square of each energy bin by a weighting factor to generate weighted squares;
• sum the weighted squares of each energy bin and compute a root-mean-square error for the photon-counting detector;
• update at least one of the parameters of the parameter vector;
• repeat the calculating, computing, weighting, summing, and updating steps until a stopping criteria is met, so as to determine the optimal parameter vector;
• correct measured count data obtained from a scan of a subject based on the determined optimal parameter vector to generate corrected count data;
• and
• reconstruct an image of a subject using the corrected count data.

A non-transitory computer-readable medium having stored thereon a program that when executed by a computer causes the computer to execute a method comprising:

• determining a normalized measured photon count for each energy bin of the photon-counting detector;
• setting an initial incident photon spectrum and an initial value for each parameter of the plurality of parameters;
• calculating, using the detector response model, a normalized modeled photon count for each energy bin of the photon-counting detector, based on the incident photon spectrum and the plurality of parameters;
• computing, for each energy bin, a square of a difference between the normalized measured photon count and the normalized modeled photon count;
• weighting the computed square of each energy bin by a weighting factor to generate weighted squares;
• summing the weighted squares of each energy bin and computing a root-mean-square error for the photon-counting detector;
• updating at least one of the parameters of the parameter vector;
• repeating the calculating, computing, weighting, summing, and updating steps until a stopping criteria is met, so as to determine the optimal parameter vector;
• correcting measured count data obtained from a scan of a subject based on the determined optimal parameter vector to generate corrected count data;
• and
• reconstructing an image of a subject using the corrected count data.