Quantitative pulse selection for photon-counting computed tomography scanning systems

Patent metadata

Field	Value
Publication number	US-2023228888-A1
Application number	US-202218065045-A
Country	US
Kind code	A1
Filing date	Dec 13, 2022
Priority date	Jan 19, 2022
Publication date	Jul 20, 2023
Grant date	—

Abstract

One embodiment is a method for counting charge events detected by a pixel in a photon-counting computed tomography (PCCT) scanning system comprising a plurality of discriminators, wherein each discriminator is associated with a respective one of a plurality of threshold voltage levels. The method includes detecting a signal output from one of the discriminators; incrementing a quantitative count corresponding to the threshold voltage level associated with the one of the discriminators if the detected discriminator output signal meets a first condition; and incrementing a qualitative count if the detected discriminator output signal meets at least one second condition.

First claim

What is claimed is:

1 . A method for counting charge events detected by a pixel in a photon-counting computed tomography (PCCT) scanning system comprising a plurality of discriminators, wherein each discriminator is associated with a respective one of a plurality of threshold voltage levels, the method comprising:
detecting a signal output from one of the discriminators; incrementing a quantitative count corresponding to the threshold voltage level associated with the one of the discriminators if the detected discriminator output signal meets a first condition; and incrementing a qualitative count if the detected discriminator output signal meets at least one second condition.

2 . The method of claim 1 , wherein the at least one second condition includes expiration of a time-over-threshold (ToT) timer.

3 . The method of claim 2 , further comprising, upon expiration of the ToT timer:
incrementing the qualitative count; and resetting the ToT timer.

4 . The method of claim 1 , wherein the at least one second condition includes the signal output from the one of the discriminators overlapping with a signal output from a discriminator associated with a neighboring pixel.

5 . The method of claim 1 , wherein the at least one second condition includes the signal output from the one of the discriminators comprising only one monotonic series of low-to-high transition and only one monotonic series of high-to-low transition.

6 . The method of claim 1 , wherein the first condition comprises an absence of the at least one second condition.

7 . The method of claim 1 , wherein the plurality of discriminators comprises five discriminators.

8 . The method of claim 1 , wherein the plurality of threshold voltage levels comprise five threshold voltage levels.

9 . The method of claim 1 , wherein each of the discriminators compares a voltage signal input to the discriminators to the threshold voltage level associated with the discriminator.

10 . The method of claim 9 , wherein an output of each of the discriminators is driven high when the voltage signal input to the discriminators exceeds the threshold voltage level associated with the discriminator.

11 . The method of claim 1 , wherein the spectral information is disregarded if a certain threshold for total number of qualitative counts is not reached.

12 . A method for counting charge events detected by a pixel in a photon-counting computed tomography (PCCT) scanning system comprising a plurality of discriminators, wherein each discriminator is associated with a respective one of a plurality of threshold voltage levels, the method comprising:
detecting a signal output from one of the discriminators; and incrementing a qualitative count upon the occurrence of at least one of:
expiration of a time-over-threshold (ToT) timer;
the signal output from the one of the discriminators overlapping with a signal output from a discriminator associated with a neighboring pixel; and
the signal output from the one of the discriminators comprising only one monotonic low-to-high transitions and monotonic high-to-low transitions;
otherwise, incrementing a quantitative count corresponding to the threshold voltage level associated with the one of the discriminators.

13 . The method of claim 12 , further comprising, upon expiration of the ToT timer:
Incrementing the qualitative count; and resetting the ToT timer.

14 . A photon-counting computed tomography (PCCT) scanning system comprising:
a plurality of discriminators, wherein each discriminator is associated with a respective one of a plurality of threshold voltage levels; and counting circuitry configured to:
detect a signal output from one of the discriminators; and
increment a quantitative count corresponding to the threshold voltage level associated with the one of the discriminators if the detected discriminator output signal meets a first condition; and
increment a qualitative count if the detected discriminator output signal meets at least one second condition.

15 . The PCCT system of claim 14 , wherein the at least one second condition includes expiration of a time-over-threshold (ToT) timer.

16 . The PCCT system of claim 15 , further comprising, upon expiration of the ToT timer:
incrementing the qualitative count; and resetting the ToT timer.

17 . The PCCT system of claim 14 , wherein the at least one second condition includes the signal output from the one of the discriminators overlapping with a signal output from a discriminator associated with a neighboring pixel.

18 . The PCCT system of claim 14 , wherein the at least one second condition includes the signal output from the one of the discriminators comprising only one monotonic series of low-to-high transitions and one monotonic series of high-to-low transitions.

19 . The PCCT system of claim 14 , wherein the first condition comprises an absence of the at least one second condition.

20 . The PCCT system of claim 14 , wherein each of the discriminators compares a voltage signal input to the discriminators to the threshold voltage level associated with the discriminator and wherein an output of each of the discriminators is driven high when the voltage signal input to the discriminators exceeds the threshold voltage level associated with the discriminator.

Assignees

• Analog Devices Inc

Inventors

• Riehl Patrick S
• Poddar Sunrita

Classifications

• G01T1/17 Primary

  Circuit arrangements not adapted to a particular type of detector {(pulse-selection circuits H03K, G01R)} · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• A61B6/4241

  using energy resolving detectors, e.g. photon counting · CPC title

• A61B6/54 Primary

  Control of apparatus or devices for radiation diagnosis · CPC title

• A61B6/58

  Testing, adjusting or calibrating thereof · CPC title