High-Z cast reflector compositions and method of manufacture

• US 20020181647A1
• Filed: 05/30/2001
• Published: 12/05/2002
• Est. Priority Date: 05/30/2001
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Duclos, Steven Jude, Venkataramani, Venkat Subramaniam
• Granted Patent: US 6,519,313 B2
• Time in Patent Office: Days
• US Class Current: 378/19
• CPC Class Codes: G01T 1/20183 Arrangements for preventing or correcting crosstalk, e.g. optical or electrical arrangements for correcting crosstalk
• CPC Class Codes: G01T 1/202 the detector being a crystal

Abstract

A scintillator pack comprises an array of scintillator pixels and an x-ray absorbing layer disposed in inter-scintillator regions between the scintillator pixels. The x-ray absorbing layer acts to absorb x-rays and protect underlying regions of the inter-scintillator regions. The x-ray absorbing layer may be formed by a number of methods including casting and melt infiltration.

Claims

1. A scintillator pack comprising:

an array of scintillator pixels; and

an x-ray absorbing layer comprising a high density x-ray absorbing material, the x-ray absorbing layer being formed in inter-scintillator regions between the scintillator pixels.

2. The scintillator pack of claim 1, wherein the x-ray absorbing layer further comprises a dielectric material, and wherein the high density x-ray absorbing material comprises particles interspersed in the dielectric material.

3. The scintillator pack of claim 2,

wherein the dielectric material is one of an epoxy, polystyrene, polymethylmethacrylate, silicate, and phosphate.

4. The scintillator pack of claim 2, wherein the high density x-ray absorbing material comprises a high density metal selected from the group consisting of hafnium, tantalum, gadolinium, lutetium, bismuth, antimony, lead, cadmium, tungsten, molybdenum, niobium, platinum, palladium, gold, silver, and alloys thereof.

5. The scintillator pack of claim 2, wherein the high density x-ray absorbing material comprises a high density metal compound selected from the group consisting of oxides, sulfates, sulfides, chalcogenides, fluorides, halides, and combinations thereof.

6. The scintillator pack of claim 5, wherein the high density x-ray absorbing material comprises a high density metal compound selected from the group consisting of hafnium oxide, tantalum oxide, rare earth oxides, gadolinium oxide, lutetium oxide, tungsten oxide, molybdenum oxide, barium oxide, bismuth oxide, and lead oxide.

7. The scintillator pack of claim 5, wherein the high density x-ray absorbing material comprises gadolinium sulfate.

8. The scintillator pack of claim 1, wherein the high density x-ray absorbing material comprises a glass or a crystalline material.

9. The scintillator pack of claim 1, wherein the high density x-ray absorbing material is a metal that reflects scintillation radiation emitted by the scintillator pixels.

10. The scintillator pack of claim 9, wherein the metal is selected from the group consisting of lead, tungsten, molybdenum, platinum, palladium, silver, and alloys thereof.

11. The scintillator pack of claim 1, wherein the high density x-ray absorbing material comprises a high density glass ceramic.

12. The scintillator pack of claim 11, wherein the high density glass ceramic comprises crystallites embedded within a glass.

13. The scintillator pack of claim 12, wherein the crystallites have an average size in the range of about 0.15 microns to about 0.35 microns.

14. The scintillator pack of claim 12, wherein the glass is a heavy metal fluoride glass.

15. The scintillator pack of claim 14, wherein the heavy metal fluoride glass is one of HBLAN (hafnium barium lanthanum aluminum sodium fluoride) and ZBLAN (zirconium barium lanthanum aluminum sodium fluoride).

16. The scintillator pack of claim 1, further comprising:

a scintillation radiation reflecting layer over the array of scintillator pixels.

18. The x-ray device of claim 17, wherein the x-ray device is a computed tomography system.

19. The x-ray device of claim 17, wherein the scintillation radiation detector comprises an array of photodetector cells.

20. The x-ray device of claim 17, wherein the scintillation radiation detector comprises at least one photodiode.

21. The x-ray device of claim 20, wherein the at least one photodiode is an array of photodiodes, wherein each photodiode of the array of photodiodes is optically coupled to a respective scintillator pixel.

17. An x-ray device comprising:

an x-ray source;

a scintillator pack comprising an array of scintillator pixels, where a pixel of the array emits scintillation radiation upon an x-ray from the x-ray source being absorbed by the pixel, and an x-ray absorbing layer comprising a high density x-ray absorbing material, the x-ray absorbing layer being formed in inter-scintillator regions between the scintillator pixels; and

a scintillation radiation detector optically coupled to the scintillator pack for detecting the scintillation radiation.

22. An x-ray detection device comprising:

a scintillator pack including an array of scintillator pixels, where a pixel of the array emits scintillation radiation upon an x-ray being absorbed by the pixel, and an x-ray absorbing layer comprising a high density x-ray absorbing material which is formed in inter-scintillator regions between the scintillator pixels; and

a scintillation radiation detector optically coupled to the scintillator pack for detecting the scintillation radiation.

23. The x-ray detection device of claim 22, wherein the scintillation radiation detector comprises an array of photodetector cells.

24. The x-ray detection device of claim 23, further comprising:

a control system coupled to the array of photodetector cells for receiving signals output from the photodetector cells in response to scintillating radiation.

26. The method of forming a scintillator pack according to claim 25, wherein the step of forming an x-ray absorbing layer comprises:

disposing a melted eutectic alloy of a metal into the inter-scintillator regions between the scintillator pixels.

27. The method of forming a scintillator pack according to claim 26, wherein the metal is selected from the group consisting of lead, bismuth, tin, silver, and alloys thereof.

28. The method of forming a scintillator pack according to claim 25, wherein the step of forming an x-ray absorbing layer comprises:

disposing a glass melt into the inter-scintillator regions between the scintillator pixels; and

cooling the glass melt to form a glass in the inter-scintillator regions.

29. The method of forming a scintillator pack according to claim 28, further comprising;

annealing the glass at a sufficient temperature to precipitate crystallites within the glass.

30. The method of forming a scintillator pack according to claim 29, wherein the glass is one of HBLAN (hafnium barium lanthanum aluminum sodium fluoride), ZBLAN (zirconium barium lanthanum aluminum sodium fluoride), rare earth borates, bismuth borosilicates, aluminates, tantalates, and tungstates.

31. The method of forming a scintillator pack according to claim 25, wherein the step of forming an x-ray absorbing layer comprises the steps of:

providing a high density x-ray absorbing powder;

dispersing the powder within a liquid matrix to form a precursor mix;

disposing the precursor mix within the inter-scintillator regions; and

solidifying the precursor mix to form a solid layer.

32. The method of forming a scintillator pack according to claim 31, wherein the step of solidifying the precursor mix step comprises:

annealing the precursor mix.

33. The method of forming a scintillator pack according to claim 31, wherein the step of solidifying the precursor mix step comprises:

treating the precursor mix with electromagnetic radiation.

34. The method of forming a scintillator pack according to claim 31, wherein the electromagnetic radiation is x-ray or ultraviolet radiation.

35. The method of forming a scintillator pack according to claim 31, wherein the step of solidifying the precursor mix step comprises:

polymerizing the precursor mix.

36. The method of forming a scintillator pack according to claim 31, further comprising:

introducing an additive into the precursor mix, where the additive prevents discoloration of the x-ray absorbing layer.

37. The method of forming a scintillator pack according to claim 31, wherein the powder comprises a high density metal compound selected from the group consisting of oxides, sulfates, sulfides, chalcogenides, fluorides, halides and combinations thereof.

38. The method of forming a scintillator pack according to claim 36, wherein the high density x-ray absorbing material comprises a high density material selected from the group consisting of hafnium oxide, tantalum oxide, rare earth oxides, gadolinium oxide, lutetium oxide, tungsten oxide, molybdenum oxide, barium oxide, bismuth oxide and lead oxide.

39. The method of forming a scintillator pack according to claim 31, wherein the powder comprises particles with an average size between about 0.15 microns and about 0.35 microns.

25. A method of forming a scintillator pack comprising the steps of:

providing an array of scintillator pixels;

forming an x-ray absorbing layer comprising a high density x-ray absorbing material in inter-scintillator regions between the scintillator pixels.