Fast dual energy for general radiography

Patent metadata

Field	Value
Publication number	US-10136868-B2
Application number	US-201514844695-A
Country	US
Kind code	B2
Filing date	Sep 3, 2015
Priority date	Sep 3, 2015
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

Some embodiments are associated with an X-ray source configured to generate X-rays directed toward an object, wherein the X-ray source is to: (i) generate a first energy X-ray pulse, (ii) switch to generate a second energy X-ray pulse, and (iii) switch back to generate another first energy X-ray pulse. A detector may be associated with multiple image pixels, and the detector includes, for each pixel: an X-ray sensitive element to receive X-rays; a first storage element and associated switch to capture information associated with the first energy X-ray pulses; and a second storage element and associated switch to capture information associated with the second energy X-ray pulse. A controller may synchronize the X-ray source and detector.

First claim

The invention claimed is:

1. A system, comprising:
an X-ray source configured to generate X-rays directed toward an object, wherein the X-ray source is to: (i) generate a first energy X-ray pulse, (ii) switch to generate a second energy X-ray pulse, and (iii) switch back to generate another first energy X-ray pulse, wherein the second energy X-ray pulse is associated with higher voltage level as compared to the first energy X-ray pulses;
a detector associated with multiple image pixels, the detector including, for each pixel:
an X-ray sensitive element to receive X-rays,
a first storage element and associated switch to capture information associated with the first energy X-ray pulses, and
a second storage element and associated switch to capture information associated with the second energy X-ray pulse; and

a controller to synchronize the X-ray source and detector.

2. The system of claim 1 , further comprising a computer configured to:
acquire imaging data associated with the first and second energy X-ray pulses; and
reconstruct at least one image from the imaging data.

3. The system of claim 1 , wherein the first and second storage elements comprise capacitors C 1 and C 2 .

4. The system of claim 3 , wherein the X-ray sensitive element comprises a photodiode with a capacitance significantly lower than capacitance of C 1 and C 2 to enable fast and substantially complete charge transfer to C 1 and C 2 .

5. The system of claim 3 , wherein the X-ray sensitive element is a pinned photodiode.

6. The system of claim 3 , wherein the capacitances of C 1 and C 2 are selected based on dynamic range requirements of low energy and high energy X-ray pulses.

7. The system of claim 3 , wherein one end of C 1 and C 2 are connected to a common reference voltage, the other end of C 1 and C 2 are connected through a first switch and a second switch to an output of the pixel, and for each pixel the detector further includes:
a reset switch connecting the output of the pixel to a known reset voltage,
an amplifier with an input connected to the output of the pixel to facilitate a substantially low electronic noise and substantially fast readout from the pixel,
a first switch coupled between C 1 and the output of the pixel, and
a second switch coupled between C 2 and the output of the pixel.

8. The system of claim 3 , wherein the detector has readout mode operation such that C 1 charges while C 2 is read and C 2 charges while C 1 is read, and further includes for each pixel:
a first switch connecting C 1 to an output of the pixel,
a second switch connecting C 2 to the output of the pixel,
a third switch connecting C 1 to the input of the amplifier, and
a fourth switch connecting C 2 to the input of the amplifier.

9. The system of claim 3 , wherein for each pixel the detector further includes:
a transistor such that the output of the pixel responses logarithmically to a photo-charge of the photodiode, wherein a reference voltage is used to control the gain of a logarithmic amplifier resulting in a weighting factor.

10. The system of claim 9 , wherein at least one weighting factor is selected based on at least one of bone density and soft tissue density.

11. The system of claim 3 , wherein for each column the detector further includes:
a subtraction element such that the output of the pixel is associated with a difference between a charge stored in C 1 and a charge stored in C 2 .

12. The system of claim 3 , wherein a weighting factor is applied to at least one of a charge stored in C 1 and a charge stored in C 2 .

13. A method, comprising:
generating, by an X-ray source, a first energy X-ray pulse;
switching the X-ray source to generate a second energy X-ray pulse;
switching back the X-ray source to generate another first energy X-ray pulse, wherein the second energy X-ray pulse is associated with higher voltage level as compared to the first energy X-ray pulses, and
wherein a detector is associated with multiple image pixels and includes, for each pixel: an X-ray sensitive element to receive X-rays, a first storage element and associated switch to capture information associated with the first energy X-ray pulses, and a second storage element and associated switch to capture information associated with the second energy X-ray pulse; and
synchronizing the X-ray source and detector by a controller.

14. The method of claim 13 , further comprising:
acquiring imaging data associated with the first and second energy X-ray pulses; and
reconstructing at least one image from the imaging data.

15. The method of claim 13 , wherein the first and second storage elements comprise capacitors C 1 and C 2 .

16. The method of claim 15 , wherein the photodiode comprises a pinned photodiode with capacitance significantly lower than capacitance of C 1 and C 2 to enable complete charge transfer to C 1 and C 2 , and the capacitances of C 1 and C 2 are selected based on dynamic range requirements of low energy and high energy X-ray pulses.

Assignees

• Zou Yun
• Sabol John Michael
• Yanoff Brian David
• Lai Hao
• Jacob Biju
• Nye Katelyn Rose
• Chen Feng
• Gen Electric

Inventors

• Zou Yun
• Sabol John Michael
• Yanoff Brian David
• Lai Hao
• Jacob Biju
• Nye Katelyn Rose
• Chen Feng

Classifications

• A61B6/4233

  using matrix detectors · CPC title

• A61B6/4208

  characterised by using a particular type of detector · CPC title

• A61B6/482 Primary

  involving multiple energy imaging · CPC title

• G01N23/087

  using polyenergetic X-rays · CPC title

• A61B6/542

  involving control of exposure · CPC title