Method of manufacturing a collimator mandrel having variable attenuation characteristics for a CT system

• US 7,266,180 B1
• Filed: 02/10/2006
• Issued: 09/04/2007
• Est. Priority Date: 08/06/2003
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Toth, Thomas L., Ross, Steven, Saunders, Rowland
• Primary Examiner(s): KAO, CHIH CHENG G
• Application Number:
  US11/276,034
• Time in Patent Office: 571 Days
• Field of Search: 378/145, 378/147, 378/148, 378/150, 378/151, 378/16, 250/505.1
• US Class Current: 378/150
• CPC Class Codes: G21K 1/02 using diaphragms, collimators
• CPC Class Codes: G21K 1/04 using variable diaphragms, shutters, choppers

Abstract

A method of manufacturing a collimator mandrel having variable attenuation characteristics is presented. The manufacturing process includes the placement of a layer of attenuating material on a core of base material. The layer of attenuating material is relatively thin and varies in thickness circumferentially around the core. The collimator mandrel may be manufactured by placing a cast about a core of non-attenuating material, filling a void between the cast and the core with an attenuating material, allowing the material to cure, and removing the cast from the assembly.

Claims

1. A method of manufacturing a collimator mandrel for a CT imaging system, the method comprising the steps of:

forming a core of base material, wherein the core includes a cylindrical rod; and

affixing a thin layer of attenuating material to the core and then machining the thin layer to have a non-uniform thickness to form the collimator mandrel.

2. The method of claim 1 wherein the base material is stainless steel.

3. The method of claim 1 wherein the attenuating material is an alloy or an epoxy.

4. A CT collimator mandrel comprising a solid cylindrical rod positioned within a layer of attenuating material, the CT collimator mandrel formed by:

forming the cylindrical rod;

sputtering a layer of attenuating material to the cylindrical rod; and

eccentrically affixing a pivot stud to each end of the cylindrical rod to support connection of the rod to an assembly.

5. The CT collimator mandrel of claim 4 further formed by machining the layer to create a desired taper.

6. The CT collimator mandrel of claim 4 wherein the attenuating material extends circumferentially around an entire length of the cylindrical rod.

7. The CT collimator mandrel of claim 4 wherein the cylindrical rod includes stainless steel and the attenuating material includes tungsten.

8. The CT collimator mandrel of claim 4 wherein the cylindrical rod has a solid core of stainless steel.

9. The CT collimator mandrel of claim 4 incorporated into a medical scanner.

10. The CT collimator mandrel of claim 9 wherein the rod has a circular cross-section.

11. The CT collimator mandrel of claim 4 further configured to operate in tandem with another collimator mandrel to filter an x-ray beam.

12. The CT collimator mandrel of claim 4 wherein the rod is rotatable about an axis extending along a length of the rod.