Collimator and detector for computed tomography systems

• US 5,799,057 A
• Filed: 12/26/1996
• Issued: 08/25/1998
• Est. Priority Date: 12/26/1996
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Mruzek, Michael Thomas, Hoffman, David M., Englert, August O.
• Primary Examiner(s): Wong, Don
• Application Number:
  US08/773,083
• Time in Patent Office: 607 Days
• Field of Search: 378/145, 378/147, 378/148, 378/149, 378/150, 378/151, 378/152, 378/154, 378/155, 378/183, 378/185, 378/186, 378/19
• US Class Current: 378/147
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/4291 the detector being combined with a grid or grating
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]

Abstract

The present invention, in one form, is a scatter collimator for a computed tomography system including an x-ray source. The scatter collimator is positioned between a detector array and an object to be imaged. The scatter collimator includes a housing, a plurality of attenuating blades and a plurality of attenuating wires. The blades and wires are mounted to the housing, and oriented substantially perpendicular to each other. Particularly, the blades and wires form a two-dimensional shielding grid. The blades also are oriented so that they are radially and focally aligned with the x-ray source. A detector element of the detector array is secured to the housing so that the blades and wires are between the detector element and the x-ray source. The detector element, in one form, includes a scintillation element which is coated with a light-retaining material.

Claims

1. A collimator for a system including an x-ray source and a detector array mounted on a gantry, said collimator comprising:

a housing; and

a grid connected to said housing, said grid comprising a plurality of blades and a plurality of attenuating wires, each of said blades being radially spaced from and extending substantially parallel to an adjacent one of said blades, said wires extending substantially perpendicular to said blades.

2. A collimator in accordance with claim 1 wherein said housing comprises:

a top rail having first and second ends;

a bottom rail having first and second ends;

a first end block and a second end block, said first end block connecting said first ends of said top rail and said bottom rail, and said second end block connecting said second ends of said top rail and said bottom rail so that said top rail and said bottom rail extend between said first end block and said second end block, and have a blade opening therebetween.

3. A collimator in accordance with claim 2 wherein each of said blades comprises a first end and a second end, said first ends of said blades mounted to said top rail, and said second ends of said blades mounted to said bottom rail so that said blades extend generally perpendicularly between said top rail and said bottom rail.

4. A collimator in accordance with claim 2 further comprising at least two positioning combs, one of said positioning combs mounted to said top rail, the other of said positioning combs mounted to said bottom rail.

5. A collimator in accordance with claim 4 wherein said attenuating blades are mounted to said positioning combs.

6. A collimator in accordance with claim 4 further comprising at least two stopping elements, one of said stopping elements connected to said top rail, the other of said stopping elements connected to said bottom rail, said stopping elements adjacent respective positioning combs.

7. A collimator in accordance with claim 2 wherein each of said attenuating wires comprise a first end and a second end, said first ends of said wires connected to said first end block, and said second ends of said wires connected to said second end block so that said attenuating wires extend across said blade opening substantially parallel to said top rail and said bottom rail.

8. A collimator in accordance with claim 1 wherein the detector array of the system includes a plurality of detector elements, and wherein said housing is configured to be secured to the detector elements.

9. An apparatus for detecting x-rays emanated from an x-ray source, said apparatus comprising at least one detector element, said detector element comprising a scintillation element coated with a light-retaining material, said apparatus further comprising a collimator, said collimator comprising a housing configured to be secured to said detector element, and a grid connected to said housing, said grid comprising a plurality of blades and a plurality of attenuating wires, each of said blades radially spaced from and extending substantially parallel to an adjacent one of said blades, said wires extending substantially perpendicular to said blades.

10. An apparatus in accordance with claim 9, wherein said light-retaining material is a dielectric coating.

11. An apparatus in accordance with claim 9 wherein said attenuating blades and said attenuating wires are composed of Tungsten.