Operation of a counting digital x-ray image detector

Patent metadata

Field	Value
Publication number	US-2016282476-A1
Application number	US-201615071850-A
Country	US
Kind code	A1
Filing date	Mar 16, 2016
Priority date	Mar 24, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

A method is disclosed for operating a counting digital X-ray image detector. Each pixel element and/or each pixel cluster is embodied as switchable between a first counting mode and a second counting mode that is different from the first. An at least first count of the number and/or energy of the events in an at least first time interval is performed for each pixel element or each pixel cluster in the first counting mode. An evaluation of the at least first count of the number and/or energy of the events is performed in an evaluation unit of the X-ray image detector. A switchover to the second counting mode is performed as a function of the number and/or energy of the events, and a second count of the number and/or energy of events counted within an at least second time interval is performed in the chosen second counting mode.

First claim

What is claimed is:

1 . A method for operating a counting digital X-ray image detector including a plurality of pixel elements, each of at least one of the plurality of pixel elements a plurality of pixel clusters composable from the plurality of pixel elements being embodied as switchable between a first counting mode and a second counting mode different from the first counting mode, the method, for each of the plurality of pixel elements or each of the plurality of pixel clusters, comprising:
performing an at least first count, of at least one of a number and energy of events in an at least first time interval in the first counting mode; performing, in an evaluation unit of the X-ray image detector, an evaluation of the at least first count of at least one of the number and energy of the events; performing a switchover to the second counting mode based on the evaluation performed; and performing, in the second counting mode, a second count of at least one of the number and energy of events counted within an at least second time interval.

2 . The method of claim 1 , wherein one of first counting mode or second counting mode is a counting mode called “simple counting mode” and wherein a count is taken of at least one of the number and energy of the events in each of the plurality of pixel elements or each of the plurality of pixel clusters.

3 . The method of claim 1 , wherein one of first counting mode or second counting mode is a counting mode called “reconstruction mode”, wherein a count is taken of at least one of the number and energy of the events, wherein one sum signal is respectively determined at each of different nodal points of neighboring pixel elements and wherein the respective sum signals are assigned to the pixel element including the relatively largest individual signal contributing to the respective sum signal.

4 . The method of claim 1 , wherein at least one threshold of at least one of the number and energy of the counted events is used for the evaluation performed.

5 . The method of claim 1 , wherein a counting mode “reconstruction mode” is chosen as the first counting mode, wherein a count is taken of at least one of the number and energy of the events, wherein one sum signal is respectively determined at each of different nodal points of neighboring pixel elements in the counting mode “reconstruction mode” and the sum signals are each respectively assigned to the respective pixel element which has the relatively largest individual signal contributing to the respective sum signal, and wherein a counting mode “simple counting mode” is chosen as the second counting mode, wherein a count is taken of at least one of the number and energy of the events in each respective pixel element or in each respective pixel cluster if the number of events in the first time interval or a prediction of the number of events in the time interval exceeds a first threshold.

6 . The method of claim 1 , wherein a counting mode “simple counting mode” is chosen as the first counting mode, wherein a count is taken of at least one of the number and energy of the events in each respective pixel element or in each respective pixel cluster and wherein a counting mode “reconstruction mode” is chosen as the second counting mode, wherein a count is taken of at least one of the number and energy of the events, wherein one respective sum signal is determined at each different nodal points of neighboring pixel elements in the counting mode “reconstruction mode” and wherein the sum signals are each respectively assigned to the respective pixel element which has the relatively largest individual signal contributing to the respective sum signal if the number of events in the first time interval or a prediction of the number of events in the time interval lies below a second threshold.

7 . The method of claim 1 , wherein the first time interval is T base,1 and is chosen to be relatively smaller than the second time interval, the second time interval being T meas .

8 . The method as claimed in claim 7 , wherein in addition, the at least one of number and energy of the events in the time interval T meas +T base,1 is represented by multiplication of the at least one of number and energy of the events in the second time interval T meas with the factor (T meas +T base,1 )/T meas , or is represented by at least one of the number and energy of the events in the second time interval T meas if the first time interval T base,1 is 10 percent or less of the second time interval T meas , or is represented by a sum from the at least one of number and energy of the events in the first time interval T base,1 and at least one of the number and energy of the events in the second time interval T meas .

9 . The method of claim 1 , wherein the difference between the first time interval and the second time interval is 10 percent or less of the first time interval.

10 . The method of claim 1 , wherein each of the performing steps are repeated n times and wherein a plurality of time intervals T base,1 to T base,n having a duration of a time interval T meas are used to calculate a gradient from at least one of the number and energy of the events in the time intervals T base,1 to T base,n for calculating at least one of the number and energy of the events to be expected in the time interval T meas .

11 . A counting digital X-ray image detector, comprising:
a plurality of pixel elements, each of at least one of the plurality of pixel elements and a plurality of pixel clusters composable from the plurality of pixel elements includes a counting unit and wherein at least one of each of the pixel elements and each of the plurality of pixel clusters is embodied as switchable between a first counting mode and a second counting mode that is different from the first; an evaluation unit; and a switchover unit, and wherein
the counting unit is configured to perform an at least first count of at least one of the number and energy of the events in an at least first time interval in the first counting mode,
the evaluation unit is configured to perform an evaluation of the at least first count of the at least one of number and energy of the events,
the switchover unit is configured to perform a switchover to the second counting mode based on the evaluation of the at least one of number and energy of the events, and
the counting unit is configured to perform a second count of the at least one of number and energy of events counted within an at least second time interval in the second counting mode.

12 . The counting digital X-ray image detector of claim 11 , wherein a counting mode “reconstruction mode” is chosen as the first counting mode, wherein a count is taken of at least one of the number and energy of the events, wherein one sum signal is respectively determined at each of different nodal points of neighboring pixel elements in the counting mode “reconstruction mode” and the sum signals are each respectively assigned to the respective pixel element which has the relatively largest individual signal contributing to the respective sum signal, and wherein a counting mode “simple counting mode” is chosen as the second counting mode, wherein a count is taken of at least one of the number and energy of the events in each respective pixel element or in each respective pixel cluster if the number of events in the first time interval or a prediction of the number of events in the time interval exceeds a first threshold.

13 . The counting digital X-ray image detector of claim 11 , wherein a counting mode “simple counting mode” is chosen as the first counting mode, wherein a count is taken of

Assignees

• Siemens Ag

Inventors

• Kappler Steffen
• Spahn Martin

Classifications

• G01T1/17 Primary

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