CT detector having a segmented optical coupler and method of manufacturing same

• US 6,933,504 B2
• Filed: 03/12/2003
• Issued: 08/23/2005
• Est. Priority Date: 03/12/2003
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hoffman, David M., Hoge, Michael F.
• Primary Examiner(s): Glick, Edward J.
• Assistant Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US10/249,052
• Publication Number:
  US 20040179645A1
• Time in Patent Office: 895 Days
• Field of Search: 378/4, 378/19, 378/98.8, 378/154, 250/370.09, 250/370.11, 250/368
• US Class Current: 250/370.11
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• 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 2223/612 biological material
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01T 1/2002 Optical details, e.g. reflecting or diffusing layers
• CPC Class Codes: G01T 1/20183 Arrangements for preventing or correcting crosstalk, e.g. optical or electrical arrangements for correcting crosstalk
• CPC Class Codes: G01T 1/20185 Coupling means between the photodiode and the scintillator, e.g. optical couplings using adhesives with wavelength-shifting fibres
• CPC Class Codes: G01T 1/202 the detector being a crystal
• 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

Abstract

The present invention is a directed to a CT detector for a CT imaging system that incorporates a segmented optical coupler between a photodiode array and a scintillator array. The segmented optical coupler also operates as a light collimator which improves the light collection efficiency of the photodiode array. The segmented optical coupler is defined by a series of reflector elements that collectively form a plurality of open cells. The open cells form light transmission cavities and facilitate the collimation of light from a scintillator to a photodiode. The cavities may be filled with optical epoxy for sealing to the photodiode array.

Claims

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

forming a scintillator array having a plurality of scintillators;

forming a photodiode array having a plurality of photodiodes;

depositing an open-celled collimator between the scintillator array and the photodiode array; and

securing the scintillator, the open-celled collimator, and the photodiode array to one another, wherein the steps of forming the scintillator array and depositing an open-celled collimator include the steps of;

mounting a block of scintillator material onto a dissolvable substrate;

dicing through the block and the dissolvable substrate to form a plurality of voids;

casting reflector material into the plurality of voids; and

dissolving the dissolvable substrate to form the open-celled collimator.

2. The method of claim 1 further comprising the step of filling each cell of the open-celled collimator with an optical coupling substance.

3. The method of claim 2 wherein the optical coupling substance includes epoxy.

4. The method of claim 1 wherein the step of securing the scintillator, the open-celled collimator, and the photodiode array includes the step of coupling a thin layer of adhesive to the open-celled collimator.

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

forming a scintillator array having a plurality of scintillators;

forming a photodiode array having a plurality of photodiodes;

depositing an open-celled collimator between the scintillator array and the photodiode array; and

securing the scintillator, the open-celled collimator, and the photodiode array to one another, wherein the steps of forming the scintillator array and depositing the open-celled collimator include the steps of;

mounting a block of scintillator material onto a thermoplastic substrate;

dicing through the block of scintillator material and at least partially through the thermoplastic material to form a plurality of voids; and

casting reflector material into the plurality of voids.