CT detector with integrated air gap

• US 6,907,101 B2
• Filed: 03/03/2003
• Issued: 06/14/2005
• Est. Priority Date: 03/03/2003
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hoffman, David M.
• Primary Examiner(s): Church, Craig E.
• Assistant Examiner(s): Kiknadze, Irakli
• Application Number:
  US10/248,929
• Publication Number:
  US 20040174951A1
• Time in Patent Office: 834 Days
• Field of Search: 378/4, 378/19, 378/98.8, 250/370.09, 250/370.11
• 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 an improved CT detector scintillator to photodiode optical coupling. The CT detector utilizes a controlled air gap between the photodiode array and the scintillator array together with an anti-reflective layer on the scintillator array. To improve the absorption of light at the photodiode array, the photodiode array includes a textured light reception surface. By incorporating a textured layer with the photodiode array, the light collection efficiency of the photodiodes is improved. The textured layer may extend along an x- and/or z-axis and the texturing may be in different forms. For example, the textured layer may include a series of pyramidally-shaped protrusions.

Claims

1. A CT detector comprising:

an array of scintillators configured to convert received x-rays to light;

an array of light detection elements in operable association with the array of scintillators and configured to output electrical signals in response to light detected from the array of scintillators, the array of light detection elements including a textured layer to receive the light emitted by the array of scintillators; and

an air gap disposed between the array of scintillators and the array of light detection elements.

2. The CT detector of claim 1 further comprising an anti-reflective layer coupled to the array of scintillators.

3. The CT detector of claim 1 wherein the textured layer includes a series of pyramidal protrusions extending along a top surface of the array of light detection elements.

4. The CT detector of claim 1 wherein the array of scintillators are two-dimensionally arranged.

5. The CT detector of claim 1 wherein the array of light detection elements are two-dimensionally arranged.

6. The CT detector of claim 1 incorporated into a medical imaging scanner.

7. A CT detector for an imaging system, the CT detector formed by:

arranging a plurality of light detection elements in an array, the light detection elements having a non-planar light detection surface;

arranging a plurality of scintillators in an array;

affixing at least one anti-reflective layer to the array of scintillators; and

coupling the arrays to one another such that a uniform air gap extends therebetween.

8. The CT detector of claim 7 further formed by texturing a top surface of the array of light detection elements such that the top surface is non-planar.

9. The CT detector of claim 8 further formed by creating a series of pyramidally-shaped protrusions in the top surface.

10. The CT detector of claim 9 further formed by creating the series of pyramidally-shaped protrusions along an entire width and length of the top surface.

11. The CT detector of claim 7 further formed by arranging the arrays two-dimensionally along an x-z axis.

12. 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 an anti-reflective layer coupled thereto; and

a photodiode diode array coupled to the scintillator array such that a non-planar gap extends between the reflective layer and the photodiode array.

13. The CT system of claim 12 further comprising a DAS connected to the photodiode array and configured to receive electrical signals from the photodiode array indicative of the high frequency electromagnetic energy received by the detector array.

14. The CT system of claim 13 wherein the photodiode diode array includes a non-planar layer.

15. The CT system of claim 14 wherein the non-planar layer includes a series of protrusions extending along an entire length and width of the photodiode array.

16. The CT system of claim 15 wherein each of the protrusions is pyramidally-shaped.

17. The CT system of claim 12 wherein the detector array is two-dimensionally arranged.

18. The CT system of claim 12 incorporated into a medical imaging scanner.

19. The CT system of claim 12 incorporated into a parcel inspection apparatus.

20. A CT detector comprising:

a scintillator array of scintillators having a light output surface configured to emit light upon receipt of x-rays; and

a photodiode array of photosensitive elements configured to detect light emitted by the scintillator array and output electrical signals indicative of light detected, the photodiode array having a non-planar light detection surface.

21. The CT detector of claim 20 wherein the scintillator array includes an anti-reflective layer coupled to the light output surface.

22. The CT detector of claim 21 further comprising a uniform air gap disposed between the anti-reflective layer and the non-planar light detection surface.

23. The CT detector of claim 20 wherein the non-planar light detection surface includes a series of pyramidally-shaped protrusions extending along an entire length and width thereof.

24. A CT detector comprising:

means for outputting light based on detected x-rays;

means for preventing light reflection coupled to the means for outputting;

means for detecting light output by the means for outputting and coupled to the means for preventing such that a non-uniform air gap extends therebetween.