| CPC A61B 6/5205 (2013.01) [A61B 6/032 (2013.01); A61B 6/4241 (2013.01); A61B 6/467 (2013.01); A61B 6/5258 (2013.01); A61B 6/583 (2013.01); A61B 6/585 (2013.01); G06T 11/005 (2013.01); G06T 2211/424 (2013.01)] | 20 Claims |
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12. A photon-counting computed tomography (PCCT) system, comprising:
an X-ray source that emits a beam of X-rays toward a subject to be imaged;
a photon-counting detector that receives the beam of X-rays attenuated by the subject, the photon-counting detector comprising a plurality of detector elements;
a data acquisition system (DAS) operably connected to the photon-counting detector and configured to:
during a scan of an imaging subject, obtain detector data from a detector element of the photon-counting detector, the detector data comprising photon counts partitioned into a plurality of energy bins based on an energy imparted by each photon on the detector element; and
encode the photon counts at the plurality of energy bins of the detector element into a single scalar output value representing a distribution of spectral information across all of the plurality of energy bins, wherein a respective single scalar output value is generated for each detector element of the plurality of detector elements; and
an image reconstructor configured to reconstruct an image, without performing a basis material decomposition process, from projection data acquired via the photon- counting detector, the projection data including each single scalar output value generated at each detector element.
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17. A method for a photon-counting computed tomography (PCCT) system, the method comprising:
during a calibration of the PCCT system, for a detector element of a photon- counting detector of the PCCT system:
performing a first calibration scan of a phantom to obtain a calibration vector for the detector element, the calibration vector including photon counts at each of a plurality of energy bins based on an energy of each photon that impinges on the detector element;
performing a second calibration scan without a scanned object, to generate a vector of air counts, the air count vector including photon counts at each of the plurality of energy bins based on the energy of each photon that impinges on the detector element;
generate a ground truth reference output of the detector element using the calibration vector;
determine a set of weights that minimizes a bias of an output of the detector element from the ground truth reference output and a variance of the output with respect to an output based on equal weights;
store the calibration vector, the air count vector, and a weight vector including the set of weights in a memory of the PCCT system; and
during a subsequent scan of an imaging subject:
obtaining photon counts at the plurality of energy bins of the detector element;
retrieving the weight vector and the air count vector from the memory;
calculating a linear weighted sum of the photon counts using the weight vector and the air count vector;
applying a correction function to the linear weighted sum to generate the output of the detector element, the correction function including parameters determined during the calibration of the PCCT system; and
reconstructing an image from projection data of the photon-counting detector, the projection data including the output of the detector element.
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