Precision self-aligning CT detector sensors

Patent metadata

Field	Value
Publication number	US-9519069-B2
Application number	US-201314020395-A
Country	US
Kind code	B2
Filing date	Sep 6, 2013
Priority date	Sep 6, 2013
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

CT detector modules are disclosed that include a module frame and a plurality of tileable detector sensors positioned on the module frame. Each of the tileable detector sensors includes an array of detector elements and a mounting structure directly or indirectly coupled to the detector elements to provide for a mounting and alignment of the detector sensor to the module frame. The mounting structure includes an alignment plate positioned generally opposite the array of detector elements, with the alignment plate having alignment pins forming a datum structure to align the detector sensor on the module frame and one or more threaded bosses configured to receive a fastener therein that secures the detector sensor to the module frame. The module frame includes keyed features that receive the alignment pins when the detector sensors are mounted on the module frame, so as to align the detector sensors on the module frame.

First claim

What is claimed is:

1. A CT system comprising:
a rotatable gantry having an opening to receive an object to be scanned;
an x-ray projection source positioned on the rotatable gantry that projects a beam of x-rays toward the object; and
a plurality of detector modules positioned on the rotatable gantry and configured to receive x-rays attenuated by the object, each of the plurality of detector modules comprising:
a module frame having a top surface and side surfaces thereon; and
a plurality of tileable detector sensors positioned on the top surface of the module frame so as to receive the x-rays attenuated by the object;

wherein each of the plurality of tileable detector sensors comprises:
a substrate layer having a first surface and a second surface opposite the first surface;
an array of detector elements configured to receive x-rays attenuated through the object and convert the x-rays into electrical signals, wherein the array of detector elements is disposed on the first surface of the substrate layer; and
a mounting structure directly or indirectly coupled to the array of detector elements and configured to provide for a mounting and alignment of the detector sensor to the module frame, wherein the mounting structure comprises:
an alignment plate positioned on the detector sensor on the second surface of the substrate layer opposite the array of detector elements, wherein the alignment plate comprises:
alignment pins forming a datum structure to align the detector sensor on the module frame; and
one or more threaded bosses configured to receive a fastener therein that secures the detector sensor to the module frame; and

a thermal gap pad positioned between the alignment plate and the top surface and the side surface of the module frame to which the detector sensor is secured, the thermal gap pad being positioned in a recessed pocket formed in the alignment plate and comprising a thermal interface material (TIM) that provides a consistent low variation thermal interface with low thermal resistance between the detector sensor and the module frame, wherein the alignment plate of the mounting structure is disposed between the substrate layer and the thermal gap pad;

wherein the module frame includes keyed features formed therein that receive the alignment pins of each respective detector sensor therein when the detector sensors are mounted on the module frame, so as to align the detector sensors on the module frame.

2. The CT system of claim 1 wherein the substrate layer comprises an electrically insulating application specific integrated circuit (ASIC) package substrate layer, and wherein each of the plurality of detector modules further comprises: ASIC electronics package electrically and mechanically coupled to the array of detector elements to receive the analog electrical signals and convert the analog electrical signals to digital signals; and the electrically insulating ASIC package substrate layer positioned on a back surface of the ASIC electronics package opposite from the array of detector elements; wherein the alignment plate of the mounting structure is affixed directly to the electrically insulating ASIC package substrate layer.

3. The CT system of claim 1 wherein the keyed features of the module frame are formed in the top surface of the module frame, and wherein the module frame further comprises threaded openings formed through the module frame that extend out to the top surface of the module frame, with the threaded openings configured to receive fasteners that secure the detector sensors to the module frame.

4. The CT system of claim 3 wherein, for each detector sensor, the mounting structure comprises a vertical mounting structure where the alignment plate has a generally planar construction that is oriented parallel to the array of detector elements, such that the alignment pins of the alignment plate are received in respective keyed features formed in the top surface of the module frame and such that the one or more threaded bosses receive a fastener positioned through a respective threaded opening in the module frame, so as to align and secure the detector sensor on the module frame.

5. The CT system of claim 1 wherein the keyed features of the module frame are formed in one of the side surfaces of the module frame, and wherein the module frame further comprises threaded openings formed in the module frame that extend out to one side surface of the module frame, with the threaded openings configured to receive fasteners that secure the detector sensors to the module frame.

6. The CT system of claim 1 wherein each of the plurality of tileable detector sensors is selectively addable to the module frame to vary an amount of coverage of the detector module along the Z-axis, with the mounting structure of each respective detector sensor aligning the detector sensors on the module frame so as to provide a plug-and-play capability for each detector sensor.

7. The CT system of claim 1 wherein the module frame comprises alignment features configured to align and mate the module frame to a rail structure affixed on the rotatable gantry.

8. The CT system of claim 1 wherein the alignment pins and the one or more threaded bosses of the alignment plate are positioned on a surface of the alignment plate opposite the second surface of the substrate layer and within an outer perimeter of the array of detector elements.

9. A detector module for receiving x-rays attenuated by an object during a CT scan procedure, the detector module comprising:
a module frame comprising a top surface and side surfaces; and
a plurality of tileable detector sensors positioned on the module frame to receive the x-rays attenuated by the object, wherein each of the plurality of detector sensors comprises:
a substrate layer having a first surface and a second surface opposite the first surface;
an array of detector pixels configured to receive x-rays attenuated through the object and convert the x-rays into electrical signals, wherein the array of detector elements is disposed on the first surface of the substrate layer;
an alignment plate directly or indirectly coupled to the array of detector elements and positioned on the second surface of the substrate layer opposite the array of detector pixels, the alignment plate including:
alignment pins forming a datum structure to align the detector sensor on the module frame; and
one or more threaded bosses configured to receive a fastener therein that secures the detector sensor to the module frame; and
a thermal gap pad positioned in a recessed pocket formed in the alignment plate such that the thermal gap pad is compressed between the alignment plate and the module frame when the detector sensor is secured to the module frame, the thermal gap pad comprising a thermal interface material (TIM) that provides a consistent low variation thermal interface with low thermal resistance between the detector sensor and the module frame, wherein the alignment plate is disposed between the substrate layer and the thermal gap pad;

wherein the module frame includes datum holes formed therein that receive the alignment pins of each respective detector sensor therein when the detector sensors are mounted on the module frame, so as to align the detector sensors on the module frame.

10. The detector module of claim 9 wherein the alignment plate comprises a generally planar alignment plate that is oriented parallel to the array of detector elements and is directly or indirectly coupled thereto, with the alignment pins and a single threaded boss being formed on the generally planar alignment plate; and wherein the alignment pins of the generally planar alignment plate are received

Assignees

• Gen Electric

Inventors

• Lacey Joseph James
• Ikhlef Abdelaziz
• Babu Baiju Zacharia

Classifications

• G01T1/16

  Measuring radiation intensity (G01T1/29 takes precedence {; self-powered detectors G01T3/006; using an ionisation chamber filled with a liquid or solid, e.g. frozen liquid, dielectric G01T3/008}) · CPC title

• A61B6/032 Primary

  Transmission computed tomography [CT] · CPC title

• G01N23/046

  using tomography, e.g. computed tomography [CT] · CPC title

• A61B6/4233

  using matrix detectors · CPC title

• G01T7/005 Primary

  calibration techniques (stabilization of spectrometer G01T1/40) · CPC title