MULTI-LAYER RADIATION DETECTOR ASSEMBLY

• US 20100102242A1
• Filed: 10/29/2008
• Published: 04/29/2010
• Est. Priority Date: 10/29/2008
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Shiang, Joseph John, Couture, Aaron Judy, Burr, Kent Charles
• Granted Patent: US 7,956,332 B2
• Time in Patent Office: Days
• US Class Current: 250/370.110
• CPC Class Codes: G01T 1/20 with scintillation detectors

Abstract

A technique is provided for forming a multi-layer radiation detector. The technique includes a charge-integrating photodetector layer provided in conjunction with a photon-counting photodetector layer. In one embodiment, a plurality of photon-counting photosensor elements are disposed adjacent to a plurality of charge-integrating photosensor elements of the respective layers. Both sets of elements are connected to readout circuitry and a data acquisition system. The detector arrangement may be used for energy discriminating computed tomography imaging and similar computed tomography systems.

Claims

1. A radiation detector comprising:

a charge integrating photodetector layer; and

a photon counting photodetector layer disposed beneath the charge integrating photodetector layer.

2. The radiation detector of claim 1, wherein the photon counting photodetector layer comprises a solid state photomultiplier layer.

3. The radiation detector of claim 1, comprising a scintillator disposed on a side of the charge integrating photodetector layer opposite to the photon counting photodetector layer and configured to receive X-ray radiation and to convert the X-ray radiation to lower energy photons suitable for detection by the charge integrating photodetector layer and the photon counting photodetector layer

4. The radiation detector of claim 1, wherein the charge integrating photodetector layer is disposed over inactive areas of the photon counting photodetector layer, and not over at least a portion of active areas of the photon counting photodetector layer.

5. The radiation detector of claim 1, wherein the charge integrating photodetector layer is disposed over substantially all of the surface area of the photon counting photodetector layer.

6. The radiation detector of claim 1, wherein the charge integrating photodetector layer comprises an amorphous silicon photodiode array or an organic photodiode array.

7. The radiation detector of claim 1, wherein the charge integrating photodetector layer comprises a semi transparent amorphous silicon photodiode array or an organic photodiode array.

8. A method for constructing a detector, the method comprising:

disposing a plurality of charge integrating photosensor elements beneath a scintillator;

disposing a plurality of photon counting photosensor elements adjacent to the plurality of charge integrating photosensor elements; and

electrically coupling the charge integrating photosensor elements and the photon counting photosensor elements to a data acquisition system.

9. The method of claim 8, wherein the charge integrating photosensor elements are disposed over inactive areas of or around the photon counting photosensor elements.

10. The method of claim 8, wherein the charge integrating photosensor elements are disposed over substantially an entire area of the photon counting photosensor elements.

11. The method of claim 8, wherein the charge integrating photosensor elements and the photon counting photosensor elements are disposed on a single semiconductor wafer.

12. The method of claim 8, further comprising:

electrically coupling the photon counting photosensor elements to resistive elements; and

coupling the resistive elements to the data acquisition system.

13. The method of claim 8, wherein the photon counting photosensor elements comprise solid state photomultiplier elements.

14. The method of claim 8, further comprising coupling read out circuitry to the data acquisition system, wherein the read out circuitry is configured to collect signals simultaneously from the charge integrating photosensor elements and the photon counting photosensor elements.

15. A detector for use in an imaging system, the detector comprising:

a scintillator configured to receive X-rays on one side thereof;

a photosensor array disposed on an opposite side of the scintillator comprising a plurality of charge integrating photosensor elements and a plurality of photon counting photosensor elements; and

a read out circuitry configured to provide a plurality of electrical signals based upon signals acquired from the charge integrating photosensor elements and the photon counting photosensor elements.

16. The detector of claim 15, wherein the detector comprises a computed tomography detector.

17. The detector of claim 15, wherein the photon counting photosensor elements comprises a solid-state photomultiplier.

18. The detector of claim 15, further comprising a data acquisition system coupled to read out circuitry and configured to collect signals provided by the read out circuitry.

19. A data acquisition system comprising:

a read out circuitry coupled to a plurality of charge integrating photosensor elements and a plurality of photon counting photosensor elements; and

the read out circuitry configured to acquire a plurality of electrical signals simultaneously from the charge integrating photosensor elements and the photon counting photosensor elements.

20. The data acquisition system of claim 19, wherein the read out circuitry distinguishes between the signals of the charge integrating photosensor elements and the photon counting photosensor elements.

21. The data acquisition system of claim 19, further configured to digitize the plurality of electrical signals from the charge integrating photosensor elements and the photon counting photosensor elements.

22. An imaging system with a detector comprising:

a radiation source configured to project X-ray photons towards the object; and

a detector module configured to receive X-ray photons attenuated by the object, the detector module comprising;

a scintillator to receive X-ray photons on one side thereof;

a photosensor array coupled to the scintillator, wherein the photosensor array comprises a plurality of charge integrating photosensor elements and a plurality of photon counting photosensor elements; and

a read out circuitry configured to provide a plurality of electrical signals to a data acquisition system based on the signals acquired simultaneously from the charge integrating photosensor elements and the photon counting photosensor elements.

23. The imaging system of claim 22, wherein the imaging system comprises at least one of a tomosynthesis system, a dual energy computed tomography system, or an energy discriminating computed tomography system.

24. The imaging system of claim 22, wherein the read out circuitry is configured to distinguish the electrical signals between the charge integrating photosensor elements and the photon counting photosensor elements.

25. The imaging system of claim 22, further comprising a processor configured to analyze the electrical signals received from the data acquisition system for post processing.

26. The imaging system of claim 25, wherein post processing comprises processing at least one of the electrical signals from the charge integrating photosensor elements or the photon counting photosensor elements for image reconstruction.

27. The imaging system of claim 25, further comprising a memory for storing the electrical signals processed for diagnosis.