Collimator assembly having multi-piece components

• US 7,010,083 B2
• Filed: 04/19/2005
• Issued: 03/07/2006
• Est. Priority Date: 05/02/2003
• Status: Expired due to Fees

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: General Electric Company
• Inventors: Hoffman, David M.
• Primary Examiner(s): Church, Craig E.
• Assistant Examiner(s): Yun, Jurie
• Application Number:
  US10/907,886
• Publication Number:
  US 20050169430A1
• Time in Patent Office: 322 Days
• Field of Search: 378/19, 378/147, 378/149, 378/186, 378/154, 250/370.09, 250/370.11
• US Class Current: 378/19
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 2223/612 biological material
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01T 1/1648 Ancillary equipment for scintillation cameras, e.g. reference markers, devices for removing motion artifacts, calibration devices adapted for flow studies G01T1/1647
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation

Abstract

The present invention is directed to a collimator assembly defined by a series of multi-piece collimator elements or plates that extend along at least one dimension of a scintillator pack. Each collimator element has a collimating component and a shielding component that are structurally independent from one another. The collimating components may be connected to the shielding components or separated by a small air gap. The shielding components are wider than the collimating components but the collimating components have a greater height. With this construction, the collimator assembly optimizes collimation and shielding with lower material requirements and reduced overall size.

Claims

1. A collimator for a CT detector array, the collimator comprising:

a first component configured to collimate high frequency electromagnetic energy rays projected from a projection source toward a subject to be scanned along a projection path, the first component having a proximate end and a distal end defined relative to the projection source;

a second component discrete from the first component and positioned at least approximate the distal end of the first component, configured to shield at least one of a scintillator edge, a reflector, and a photodiode of a CT detector array; and

wherein the first component is constructed from material different from the second component.

2. The collimator of claim 1 wherein the first component is independent from the second component.

3. The collimator of claim 1 wherein the first component has a width narrower than a width of the second component.

4. The collimator of claim 1 wherein the first component has a thickness greater than a thickness of the second component parallel to the projection path.

5. The collimator of claim 4 wherein the first component has a width less than 200 microns.

6. The collimator of claim 4 wherein the first component and the second component are constructed from materials having high atomic numbers.

7. The collimator of claim 6 wherein the first component is constructed from at least tungsten.

8. A CT detector array assembly comprising:

a scintillator array configured to output light when impinged by x-rays;

a plurality of collimating elements arranged to filter x-rays projected at the scintillator array by an x-ray source;

a plurality of shielding elements secured to the scintillator array and arranged to at least shield scintillator edges from x-ray absorption; and

a photodiode array configured to detect light output of the scintillator array and output a series of electrical signals that can be processed to reconstruct a CT image.

9. The assembly of claim 8 wherein each shielding element has a width greater than a width of each collimating element along an x-axis.

10. The assembly of claim 9 wherein each collimating element has a width not exceeding approximately 200 microns.

11. The assembly of claim 10 wherein each collimating element has a width not exceeding approximately 50 microns.

12. The assembly of claim 11 wherein each collimating element has a width of approximately 25 microns.

13. The assembly of claim 8 where the plurality of collimating elements and the plurality of shielding elements are fabricated from at least one material having a high atomic number.

14. The assembly of claim 8 wherein the plurality of shielding elements is fabricated from one of composite materials and cast materials.

15. The assembly of claim 8 incorporated into a medical imaging CT scanner.

16. A CT detector array comprising:

a scintillator pack having a plurality of scintillators arranged in a cellular array;

a plurality of shielding elements secured to the scintillator pack such that a shielding element is formed between adjacent cells of scintillators;

an array of collimator elements wherein each collimator element generally aligns with a corresponding shielding element; and

a photodiode array coupled to the scintillator pack.

17. The CT detector of claim 16 wherein the shielding elements are independent of the collimating elements.

18. The CT detector of claim 16 wherein the shielding elements are formed of shielding material that is cast between adjacent cells of scintillators.

19. The CT detector of claim 16 wherein each collimator element has a thickness that exceeds a thickness of each shielding element along a y-axis.