Image quality in photon counting-mode detector systems
AssigneePrismatic Sensors AB
InventorsHans Bornefalk, Mats Danielsson, Christer Svensson
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Abstract
The current invention applies to photon counting silicon x-ray detectors with energy discriminating capabilities and applications in x-ray imaging systems. The overall image quality produced by such a system is improved by the presented novel methods for optimally using the energy information in Compton events and making selective use of counts induced from charges collected in neighboring pixels. The pile-up problem during high-flux imaging regimes is reduced by a novel method for signal reset, which improves the count efficiency by reducing the risk of losing event due to signal pile-up in the read out electronics chain.
Claims25
A method for extracting energy information from Compton events in a photon counting detector, said method comprising the steps of:
- allocating events according to their detected energy based on a plurality of energy thresholds, wherein said thresholds define a plurality of energy bins, and each energy bin has an associated energy bin function;
- inverting a detector response function of said photon counting detector;
- and
- integrating energy bin functions with the inverted detector response function to obtain a distribution of original x-ray quantum energies of events detected in each energy bin.
An apparatus for extracting energy information from Compton events in a photon counting detector, said apparatus comprising:
- means for allocating events according to their detected energy based on a plurality of energy thresholds, wherein said thresholds define a plurality of energy bins, and each energy bin has an associated energy bin function;
- means for inverting a detector response function of said photon counting detector;
- and
- means for integrating energy bin functions with the inverted detector response function to obtain a distribution of original x-ray quantum energies of events detected in each energy bin.
A method for image reconstruction based on energy information from a photon counting detector, wherein said method includes selecting between two different image reconstruction triodes:
- i) a first image reconstruction mode in which low energy bins with a high fraction of noise counts are included in the image reconstruction;
- and ii) a second image reconstruction mode in which low energy bins with a high fraction of noise counts are excluded in the image reconstruction.
An apparatus for image reconstruction based on energy information from a photon counting detector, wherein said apparatus is configured for operation based on two different image reconstruction modes:
- i) a first image reconstruction mode in which low energy bins with a high fraction of noise counts are included in the image reconstruction;
- and ii) a second image reconstruction mode in which low energy bins with a high fraction of noise counts are excluded in the image reconstruction.
Dependencies are inferred from the claim text.