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

• US 7,064,334 B2
• Filed: 05/02/2005
• Issued: 06/20/2006
• Est. Priority Date: 03/12/2003
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hoge, Michael F, Hoffman, David M.
• Primary Examiner(s): GAGLIARDI, ALBERT J
• Application Number:
  US10/908,209
• Publication Number:
  US 20050184242A1
• Time in Patent Office: 414 Days
• Field of Search: 250/368, 250/370.11
• US Class Current: 250/368
• 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 CT detector comprising:

a plurality of scintillators arranged in an array to receive x-rays and output light in response to the reception of x-rays;

a plurality of reflector elements with a single reflector element disposed between adjacent scintillators;

a plurality of light detection elements arranged in an array to output electrical signals in response to light detected from the plurality of scintillators; and

an optical coupler to secure the plurality of scintillators to the plurality of light detection elements, the optical coupler having a plurality of air cavities defined by cavity plates disposed between the plurality of scintillators and the plurality of light detection elements such that each reflector element is aligned with a corresponding cavity plate and has a width substantially equal to that of the corresponding cavity plate, wherein the optical coupler includes a gridded screen defining a plurality of light transmission cavities between the plurality of scintillators and the plurality of light detection elements.

2. The CT detector of claim 1 wherein the optical coupler includes a plurality of integrated reflector elements.

3. The CT detector of claim 1 wherein the gridded screen includes an etched metallic grid bonded to the plurality of scintillators.

4. The CT detector of claim 1 wherein the light transmission cavities include optical coupling epoxy.

5. A CT detector comprising:

a plurality of scintillators arranged in an array to receive x-rays and output light in response to the reception of x-rays;

a plurality of reflector elements with a single reflector element disposed between adjacent scintilators;

a plurality of light detection elements arranged in an array to output electrical signals in response to light detected from the plurality of scintillators; and

an optical coupler to secure the plurality of scintillators to the plurality of light detection elements, the optical coupler having a plurality of cavities defined by cavity plates disposed between the plurality of scintillators and the plurality of light detection elements such that each reflector element is aligned with a corresponding cavity plate and has a width substantially equal to that of the corresponding cavity plate, wherein the optical coupler includes a plurality of integrated reflector elements and wherein the plurality of integrated reflector elements is arranged to define a plurality optical coupling cells, each optical coupling cell configured to secure one scintillator to one light detection element, and wherein each optical coupling cell includes an optical epoxy, wherein the optical coupler includes a gridded screen defining a plurality of light transmission cavities between the plurality of scintillators and the plurality of light detection elements.

6. A CT detector comprising:

a plurality of scintillators arranged in an array to receive x-rays and output light in response to the reception of x-rays;

a plurality of reflector elements with a single reflector element disposed between adjacent scintillators;

a plurality of light detection elements arranged in an array to output electrical signals in response to light detected from the plurality of scintillators; and

an optical coupler to secure the plurality of scintillators to the plurality of light detection elements, the optical coupler having a plurality of cavities defined by cavity plates disposed between the plurality of scintillators and the plurality of light detection elements such that each reflector element is aligned with a corresponding cavity plate and has a width substantially equal to that of the corresponding cavity plate, wherein the optical coupler includes a plurality of integrated reflector elements and wherein the plurality of integrated reflector elements is arranged to define a plurality optical coupling cells, each optical coupling cell configured to secure one scintillator to one light detection element, and wherein each optical coupling cell includes a thermoplastic material, wherein the optical coupler includes a gridded screen defining a plurality of light transmission cavities between the plurality of scintillators and the plurality of light detection elements.