CT detector array with uniform cross-talk

• US 6,859,514 B2
• Filed: 03/14/2003
• Issued: 02/22/2005
• Est. Priority Date: 03/14/2003
• 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): Artman, Thomas R
• Application Number:
  US10/249,092
• Publication Number:
  US 20040179650A1
• Time in Patent Office: 711 Days
• Field of Search: 250/368, 250/370.09, 250/370.11, 378/19, 378/98.8
• US Class Current: 378/19
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4411 the apparatus being modular A61B6/4283 takes precedence
• CPC Class Codes: G01T 1/20182 Modular detectors, e.g. tiled scintillators or tiled photodiodes stacked detectors G01T1/20181
• CPC Class Codes: G01T 1/20183 Arrangements for preventing or correcting crosstalk, e.g. optical or electrical arrangements for correcting crosstalk

Abstract

The present invention is directed to a CT detector array having uniform cross-talk. Discontinuities in cross-talk between adjacent CT detectors of a CT detector array are minimized by increasing the cross-talk at the boundaries of adjacent CT detectors. Discontinuities throughout a CT detector contribute to artifact presence in a final reconstructed image, therefore, it is preferred that cross-talk throughout the CT detector array be relatively uniform. Reducing the width of reflector material between adjacent CT detectors increases the cross-talk between the CT detectors. This increase in cross-talk offsets the reduced cross-talk that typically occurs between scintillators, optical epoxy layers, and photodiodes at the CT detector interface. Cross-talk may also be increased by reducing the amount of chrome deposited in the reflector between CT detectors or reducing the levels of titanium oxide typically used in reflector layers.

Claims

1. A CT detector array comprising:

a plurality of CT detectors arranged to receive x-rays impinged by a subject and output electrical signals to a data acquisition system;

each of the CT detectors having a plurality of detector elements, each detector element including a scintillator and a photodiode optically coupled to one another; and

the CT detectors aligned relative to one another such the cross-talk throughout the plurality of CT detectors is substantially uniform and wherein cross-talk between CT detectors exceeds cross-talk between detector elements.

2. The CT detector array of claim 1 further comprising a reflector element between each adjacent detector element.

3. The CT detector array of claim 2 further comprising a reflector wall between each CT detector.

4. The CT detector array of claim 3 wherein the reflector wall has less thickness than each of the reflector elements.

5. The CT detector array of claim 1 absent substantial cross-talk discontinuities.

6. 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 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 absent substantial cross-talk discontinuities and including;

a plurality of CT detectors, each CT detector including a plurality of detector elements; and

wherein cross-talk between CT detectors exceeds cross-talk between detector elements.

7. The CT system of claim 6 wherein the plurality of CT detectors is separated from one another by a reflector wall having a thickness less than that of a reflector element disposed between adjacent detector elements of each CT detector.

8. The CT system of claim 6 wherein the plurality of CT detectors is separated from one another by a reflector wall fabricated of a material absent chrome.

9. The CT system of claim 6 wherein the plurality of CT detectors is separated from one another by a reflector wall fabricated of a material with reduced TiO₂ content.

10. The CT system of claim 6 wherein the substantial cross-talk discontinuities includes optical cross-talk discontinuities.

11. The CT system of claim 6 incorporated into at least one of a mechanical scanner and a parcel inspection apparatus.

12. A method of manufacturing a CT detector array comprising the steps of:

forming a plurality of CT detectors in an array, each CT detector including a plurality of detector elements;

forming each detector element by optically coupling a scintillator to a photodiode;

depositing reflector material between adjacent scintillators;

forming a reflector wall between adjacent CT detectors, the reflector wall having a thickness greater than that of the reflector material between adjacent scintillators; and

connecting the plurality of CT detectors to one another such that cross-talk throughout the connected plurality of CT detectors is substantially uniform.

13. The method of claim 12 further comprising the step of disposing a reflector wall between each CT detector, the reflector wall absent chrome.

14. The method of claim 12 wherein the step of connecting further includes the step of affixing the CT detectors to one another such that the array of CT detectors is absent cross-talk discontinuities.

15. The method of claim 12 wherein the step of connecting further includes the step of affixing the CT detectors to one another such that cross-talk between each CT detector is increased relative to cross-talk between the plurality of detector elements of each CT detector.

16. The method of claim 12 wherein the plurality of CT detectors includes a number of backlit photodiode arrays.

17. A method of manufacturing a CT detector array comprising the steps of:

forming a plurality of CT detectors in an array, each CT detector including a plurality of detector elements; and

connecting the plurality of CT detectors to one another such that cross-talk throughout the connected plurality of CT detectors is substantially uniform; and

wherein the step of connecting further includes the step of affixing the CT detectors to one another such that cross-talk between each CT detector is increased relative to cross-talk between the plurality of detector elements of each CT detector.

18. A CT detector assembly comprising:

a first CT detector module having a first plurality of detector elements separated from one another by a first layer of reflective material;

a second CT detector module having a second plurality of detector elements separated from one another by a second layer of reflective material; and

a reflector of reflector material disposed between the first and the second CT detector modules the reflector having a thickness of reflector material thicker than that of the reflective material between detector elements of the first and the second CT detector modules such that cross-talk is substantially uniform across the first and second CT detector modules.