Thermal sensing detector cell for a computed tomography system and method of manufacturing same

• US 7,167,539 B1
• Filed: 08/01/2003
• Issued: 01/23/2007
• Est. Priority Date: 02/25/2002
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hoffman, David M.
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US10/604,589
• Time in Patent Office: 1,271 Days
• Field of Search: 378/4, 378/19, 250/336.1, 250/339.01, 250/339.02, 250/370.08, 250/370.09
• US Class Current: 378/19
• 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
• CPC Class Codes: G01V 5/226 using tomography

Abstract

The present invention provides a method of manufacturing a CT detector cell having an x-ray absorption component and a thermal sensing component. The thermal sensing component is configured to detect thermal differentials in the absorption component resulting from the absorption of x-rays.

Claims

1. A method of manufacturing an x-ray detector sensor array for use with CT systems, the method comprising the steps of:

determining a high density material capable of changing in temperature upon absorption of radiation;

forming an absorption array having a plurality of absorption cells from the high density material; and

coupling a thermal sensing array having a plurality of thermal sensing cells to the absorption array.

2. The method of claim 1 wherein the step of forming an absorption array includes the step of forming a sheet of the high density material.

3. The method of claim 2 further comprising the step of etching the sheet to form a pixilated absorption array having a plurality of pixilated absorption cells.

4. The method of claim 2 further comprising the step of laser-cutting the sheet to form a pixilated absorption array having a plurality of pixilated absorption cells.

5. The method of claim 1 wherein the step of forming an absorption array includes the step of columnating the high density material.

6. The method of claim 1 wherein the step of forming an absorption array includes the steps of sputtering the high density material;

and one of;

etching the high density material;

laser-cutting the high density material; and

masking the high density material.

7. A CT detector array manufacturing process comprising the steps of:

shaping a bulk of high density material into a block;

pixilating the block to form a plurality of x-ray absorption component cells; and

affixing a plurality of thermal sensing cells formed in an array to the plurality of x-ray absorption component cells.

8. The process of claim 7 wherein the step of pixilating includes the step of laser cutting the block along one dimension so as to form the plurality of x-ray absorption component cells.

9. The process of claim 8 further comprising the step of laser cutting the block along another dimension perpendicular to the one dimension.

10. The process of claim 7 wherein the high density material is configured to experience detectable thermal changes upon reception of x-rays.

11. The process of claim 10 wherein the high density material is further configured to experience thermal changes proportionally to the amount of x-rays received.

12. The process of claim 11 wherein the plurality of thermal sensing cells is configured to detect thermal changes in the plurality of x-ray absorption component cells.

13. The process of claim 7 wherein the block is formed of lead and the plurality of thermal sensing cells is further configured to output electrical signals indicative of x-ray absorption by the plurality of x-ray absorption component cells.

14. A method of CT detector manufacture, the method comprising the steps of:

forming a sheet of x-ray absorption material;

etching the sheet such that an array of absorption components is formed; and

coupling an array of thermal sensing components to the array of absorption components.

15. The method of claim 14 wherein the step of etching includes laser cutting the sheet along two dimensions.

16. The method of claim 14 wherein the step of etching includes ion beam milling the sheet to form the array of absorption components.

17. The method of claim 14 wherein the step of etching includes:

applying a mask to the sheet;

submersing the sheet in a chemical etchant;

removing the sheet from the chemical etchant; and

allowing the etchant to dry.

18. The method of claim 14 wherein the step of etching includes:

applying a layer of plasma to the sheet;

loading the sheet in a vacuum chamber;

creating a vacuum in the chamber;

filling the chamber with a reactive gas;

creating a frequency field in the chamber;

energizing the layer of plasma to an energized state;

allowing the energized plasma to convert unprotected portions of the sheet to a number of volatile components; and

removing the volatile components with a vacuum.

19. The method of claim 14 wherein the x-ray absorption material includes lead.

20. The method of claim 14 wherein the array of thermal sensing components is configured to detect temperature changes in the array of x-ray absorption components.