Data acquisition system of photon counting detector array
View Patent ↗Among other things, one or more techniques and/or systems are described for generating an output of a detector cell of a photon counting detector array. A counter block generates integration data and photon counting data associated with the photon counting detector array. Responsive to a number of detection events counted during a measurement interval (e.g., a view) not exceeding a first detection event count threshold, a first output may be generated based upon the photon counting data. Responsive to the number of detection events exceeding a second detection event count threshold, a second output may be generated based upon the integration data. Responsive to the number of detection events being between the first detection event count threshold and the second detection event count threshold, a blended output may be generated based upon the photon counting data and the integration data.
1. An electronics arrangement of a photon counting detector array, comprising:
an integration circuit configured to integrate charge generated by a detector cell of the photon counting detector array to generate a voltage signal;
a charge injection circuit configured to inject a charge into the integration circuit in response to the voltage signal exceeding a specified threshold, the injected charge configured to reset the integration circuit;
a photon counting circuit configured to identify detection events based upon the voltage signal; and
a counter block configured to:
generate integration data indicative of an amount of charge integrated by the integration circuit during a measurement interval based upon a number of resets to the integration circuit during the measurement interval;
generate photon counting data indicative of a number of detection events identified by the photon counting circuit during the measurement interval; and
responsive to the number of detection events being between a first detection event count threshold and a second detection event count threshold for the measurement interval:
apply a first blending weight to the integration data to create weighted integration data;
apply a second blending weight to the photon counting data to create weighted photon counting data; and
generate a blended output based upon the weighted integration data and the weighted photon counting data.
2. The electronics arrangement of claim 1 , the counter block configured to:
responsive to the number of detection events not exceeding the first detection event count threshold for the measurement interval, generate an output based upon the photon counting data but not the integration data.
3. The electronics arrangement of claim 1 , the counter block configured to:
responsive to the number of detection events exceeding the second detection event count threshold for the measurement interval, generate an output based upon the integration data but not the photon counting data.
4. The electronics arrangement of claim 1 , the counter block configured to:
apply a scaling factor to at least one of the integration data or the photon counting data prior to applying the first blending weight and applying the second blending weight to normalize the integration data with respect to the photon counting data.
5. The electronics arrangement of claim 1 , the counter block configured to:
derive the first blending weight and the second blending weight using a linear interpolation blending function, the first blending weight and the second blending weight derived based upon the number of detection events during the measurement interval.
6. The electronics arrangement of claim 5 , the linear interpolation blending function comprising a function w(x)=x, where x corresponds to a normalized crossover region coordinate.
7. The electronics arrangement of claim 1 , the counter block configured to:
derive the first blending weight and the second blending weight using a first-derivative matching blending function.
8. The electronics arrangement of claim 1 , the counter block configured to:
derive the first blending weight and the second blending weight based upon a first signal to noise and error ratio (SNER) for the integration data and a second SNER for the photon counting data.
9. A method for determining an output for a detector cell of a photon counting detector array, comprising:
generating integration data indicative of an amount of charge integrated by an integration circuit during a measurement interval based upon a number of resets to the integration circuit during the measurement interval;
generating photon counting data indicative of a number of detection events identified by a photon counting circuit during the measurement interval;
responsive to the number of detection events not exceeding a first detection event count threshold for the measurement interval, generating a first output based upon the photon counting data;
responsive to the number of detection events exceeding a second detection event count threshold for the measurement interval, generating a second output based upon the integration data; and
responsive to the number of detection events being between the first detection event count threshold and the second detection event count threshold for the measurement interval, generating a blended output based upon the photon counting data and the integration data.
10. The method of claim 9 , comprising, responsive to the number of detection events being between the first detection event count threshold and the second detection event count threshold for the measurement interval:
applying a scaling factor to at least one of the integration data or the photon counting data prior to the generating a blended output.
11. The method of claim 9 , the generating a blended output comprising:
applying a first blending weight to the integration data to create weighted integration data;
applying a second blending weight to the photon counting data to create weighted photon counting data; and
generating the blended output based upon the weighted integration data and the weighted photon counting data, the first blending weight and the second blending weight derived using a linear interpolation blending function.
12. The method of claim 11 , wherein the first blending weight and the second blending weight are derived based upon the number of detection events during the measurement interval.
13. The method of claim 9 , the generating a blended output comprising:
applying a first blending weight to the integration data to create weighted integration data;
applying a second blending weight to the photon counting data to create weighted photon counting data; and
generating the blended output based upon the weighted integration data and the weighted photon counting data, the first blending weight and the second blending weight derived using a first-derivative matching blending function.
14. The method of claim 9 , the generating a blended output comprising:
applying a first blending weight to the integration data to create weighted integration data;
applying a second blending weight to the photon counting data to create weighted photon counting data; and
generating the blended output based upon the weighted integration data and the weighted photon counting data, the first blending weight and the second blending weight derived based upon a first signal to noise and error ratio (SNER) for the integration data and a second SNER for the photon counting data.
15. A radiation imaging system, comprising:
an ionizing radiation source; and
a photon counting detector array comprising one or more detector cells configured to detect radiation from the ionizing radiation source, a first detector cell comprising:
a radiation conversion element configured to convert radiation detected by the first detector cell into charge; and
an electronics arrangement comprising:
an integration circuit configured to integrate the charge to generate a voltage signal;
a photon counting circuit configured to identify detection events based upon the voltage signal; and
a counter block configured to:
generate integration data indicative of an amount of the charge that is integrated by the integration circuit during a measurement interval based upon a number of resets to the integration circuit during the measurement interval;
generate photon counting data indicative of a number of detection events identified by the photon counting circuit during the measurement interval; and
responsive to the number of detection events being between a first detection event count threshold and a second detection event count threshold for the measurement interval, generate a blended output based upon the photon counting data and the integration data.
16. The radiation imaging system of claim 15 , the counter block configured to:
apply a scaling factor to at least one of the integration data or the photon counting data prior to generating the blended output to normalize the integration data with respect to the photon counting data.
17. The radiation imaging system of claim 15 , the counter block configured to:
responsive to the number of detection events not exceeding the first detection event count threshold for the measurement interval, generate an output based upon the photon counting data but not the integration data; and
responsive to the number of detection events exceeding the second detection event count threshold for the measurement interval, generate an output based upon the integration data but not the photon counting data.
18. The radiation imaging system of claim 15 , the radiation conversion element comprising a direct conversion material configured to convert the radiation directly into charge.
19. The radiation imaging system of claim 15 , the radiation comprising at least one of x-ray radiation or gamma radiation.
20. The radiation imaging system of claim 15 , wherein the integration data is weighted relative to the photon counting data prior to generating the blended output to normalize the integration data with respect to the photon counting data.