Scintillator array having a reflector with integrated air gaps

• US 6,947,517 B2
• Filed: 03/03/2003
• Issued: 09/20/2005
• Est. Priority Date: 03/03/2003
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Hoffman, David M.
• Primary Examiner(s): Church, Craig E.
• Assistant Examiner(s): Kiknadze, Irakli
• Application Number:
  US10/248,930
• Publication Number:
  US 20040174952A1
• Time in Patent Office: 932 Days
• Field of Search: 378/4, 378/19, 250/367, 250/368, 250/483.1, 250/370.09, 250/370.11, 156/247
• US Class Current: 378/19
• CPC Class Codes: G01T 1/2002 Optical details, e.g. reflecting or diffusing layers
• CPC Class Codes: G01T 1/2985 In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); using external radiation sources A61B6/02

Abstract

The present invention is directed to a scintillator array having an integrated air gap. By integrating an air gap within the reflector, light collection efficiency is improved while simultaneously lowering cross-talk between scintillators. That is, implementing a reflector without chromium oxide (Cr₂O₃) increases light reflectivity and an air gap lowers cross talk through the reflector. To further improve the reflectivity, the base reflector material may be coated with a low index material and a reflective material such as silver.

Claims

1. A CT detector comprising:

a scintillator array of scintillator elements arranged to receive x-rays from an x-ray projection source and output light in proportion to the x-rays received;

a cast reflector integrally disposed between adjacent scintillators of the scintillator array; and

a single air gap disposed within the cast reflector such that a single space is formed between adjacent scintillators of the scintillator array.

2. The CT detector of claim 1 further comprising a low index material coating the cast reflector.

3. The CT detector of claim 2 further comprising reflective material coating the low index material.

4. The CT detector of claim 1 wherein the cast reflector includes an epoxy doped with TiO₂.

5. The CT detector of claim 1 absent CT₂O₃.

6. The CT detector of claim 1 wherein the air gap is defined by a U-shaped channel.

7. The CT detector of claim 6 further comprising a photodiode array of photodiodes optically coupled to the scintillator array via an optical coupler.

8. The CT detector of claim 7 wherein the U-shaped channel fails to extend to the optical coupler.

9. A CT detector having a scintillator array optically coupled to a photodiode array, the CT detector formed by:

creating voids between adjacent scintillators of the scintillator array;

disposing a cast reflector within each of the voids;

creating a single air gap in the cast reflector between adjacent scintillators; and

coupling the photodiode array to the scintillator array.

10. The CT detector of claim 9 wherein creating air gaps in the cast reflector includes dicing the cast reflector.

11. The CT detector of claim 9 further farmed by depositing a low index material in the air gaps.

12. The CT detector of claim 11 further formed by coating the low index material with a reflective material.

13. The CT detector of claim 12 wherein the reflective material includes silver.

14. The CT detector of claim 9 further formed by doping the cast reflector with TiO₂ prior to disposal of the cast reflector in the voids.

15. The CT detector of claim 9 wherein the cast reflector is an epoxy.

16. The CT detector of claim 9 wherein the cast reflector is absent of Cr₂O₃.

17. A CT system comprising:

a rotatable gantry having a bore centrally disposed therein;

a table movable fore and aft through the bore and configured to position a subject for CT data acquisition;

a high frequency electromagnetic energy projection source positioned within the rotatable gantry and configured to project high frequency electromagnetic energy toward the subject; and

a detector array disposed within the rotatable gantry and configured to detect high frequency electromagnetic energy projected by the projection source and impinged by the subject, the detector array including;

a scintillator array having a plurality of scintillators and wherein the scintillator array includes a reflector between adjacent scintillators, the reflector directly contacting the plurality of scintillators and having an integrated air gap; and

a photodiode array coupled to the scintillator array and configured to produce electrical signals in response to light emitted by the scintillator army.

18. The CT system of claim 17 wherein the reflector further includes a layer of epoxy.

19. The CT system of claim 18 wherein the reflector further includes a coating of low index material.

20. The CT system of claim 19 wherein The reflector further includes a layer of silver coating the low index material.

21. The CT system of claim 17 incorporated into at least one of a medical imaging scanner and a parcel inspection apparatus.

22. A scintillation array comprising:

a plurality of scintillators arranged to receive x-rays and generate light in response thereto;

a reflector disposed between adjacent scintillators;

a plurality of voids integrated in the reflector along at least one dimension such that a single void is disposed between adjacent scintillators along the at least one dimension; and

the reflector formed of a material absent Cr₂O₃.

23. The scintillator array of claim 22 further comprising a coating of low index material on the reflector.

24. The scintillator array of claim 23 further comprising a coating of reflective material on the low index material.

25. The scintillator amy of claim 22 further comprising a U-shaped air channel disposed in the reflector.

26. A method of manufacturing a scintillator array comprising the steps of:

creating voids between adjacent scintillators of the scintillator array;

depositing a cast reflector within each of the voids such that the cast reflector directly contacts the scintillators;

creating air gaps in the cast reflector disposed within the voids; and

coupling the photodiode array to the scintillator array.