X-RAY IMAGER WITH LENS ARRAY AND TRANSPARENT NON-STRUCTURED SCINTILLATOR

• US 20140264043A1
• Filed: 03/12/2014
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Varex Imaging Corporation
• Original Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Inventors: Ganguly, Arundhuti, Mollov, Ivan
• Granted Patent: US 9,606,244 B2
• Time in Patent Office: Days
• US Class Current: 250/362
• CPC Class Codes: G01T 1/2006 using a combination of a scintillator and photodetector which measures the means radiation intensity
• CPC Class Codes: G01T 1/20185 Coupling means between the photodiode and the scintillator, e.g. optical couplings using adhesives with wavelength-shifting fibres

Abstract

An x-ray imager includes a scintillator layer configured to generate light from x-rays, a detector array configured to detect light generated in the scintillator layer, and a lens array situated between the scintillator layer and the detector array. The lens array may be configured to collect light and focus the collected light to the detector array.

Claims

1. An x-ray imager, comprising:

a scintillator layer configured to generate light from x-rays, wherein the scintillator layer is transparent, non-structured and non-pixellated;

a detector array comprising a plurality of photosensitive elements configured to detect light generated in the scintillator layer; and

a lens array, wherein the lens array comprises a plurality of lenses, each being configured to collect light and focus the collected light to corresponding one of the plurality of photosensitive elements.

2. The x-ray imager of claim 1 wherein each of the lenses comprises an anti-reflective coating.

3. The x-ray imager of claim 1 wherein the lens array is attached to the scintillator layer.

4. The x-ray imager of claim 1 wherein the lens array is attached to the detector array.

5. The x-ray imager of claim 1 wherein the lens array is attached to the scintillator layer and the detector array.

6. The x-ray imager of claim 1 wherein the lens array comprises multiple lens layers.

7. The x-ray imager of claim 1 wherein each lens has a size substantially greater than a size of a photosensitive element covered by the lens.

8. The x-ray imager of claim 1 wherein the lens array comprises a fill factor greater than 90%.

9. The x-ray imager of claim 1 wherein the scintillator layer, the detector array, and the lens array are arranged in a configuration such that in use x-rays traverse the detector array before propagating in the scintillator layer.

10. The x-ray imager of claim 1 wherein the scintillator layer, the detector array, and the lens array are arranged in a configuration such that in use x-rays are incident on the scintillator layer before propagating in the detector array.

11. The x-ray imager of claim 1 wherein the detector array further comprises a plurality of light blockers each being situated between adjacent photosensitive elements.

12. The x-ray imager of claim 1 wherein the scintillator comprises a first surface proximal to the lens array, a second surface distal to the lens array, and side surfaces, wherein the first surface is polished.

13. The x-ray imager of claim 12 wherein the second surface is covered with a reflective coating and the side surfaces are covered with a light absorbing material.

14. The x-ray imager of claim 1 wherein the scintillator comprises a first surface proximal to the lens array, a second surface distal to the lens array, and side surfaces, wherein the first surface is covered with an antireflective coating.

15. The x-ray imager of claim 14 wherein the second surface and side surfaces are covered with an antireflective coating.

16. The x-ray imager of claim 1 further comprising an opaque mask situated between the lens array and the detector array, wherein the mask comprises a plurality of transparent areas each being positioned in front of a corresponding photosensitive element.

17. The x-ray imager of claim 1 wherein the scintillator layer has an exterior surface, wherein the entire exterior surface except for a side facing the detector array is coated by a light absorbing material.

18. An x-ray imager, comprising:

a scintillator layer configured to generate light from x-rays; and

a detector array comprising a plurality of photosensitive elements configured to detect light generated in the scintillator layer;

wherein;

the scintillator layer is transparent, non-structured and non-pixellated; and

the scintillator layer has a first surface proximal to the detector array, the first surface of the scintillator layer comprises a plurality of portions each having a curved surface facing toward one of the plurality of photosensitive elements.

19. The x-ray imager of claim 18 wherein each of the plurality of portions of the first surface of the scintillator layer has a convex surface pointing toward the one of the plurality of the photosensitive elements.

20. The x-ray imager of claim 19 wherein each of the plurality of portions of the first surface of the scintillator layer has a concave surface facing the one of the plurality of the photosensitive elements.

21. An x-ray imager, comprising:

a scintillator layer configured to generate light from x-rays, wherein the scintillator layer is transparent, non-structured and non-pixellated;

a detector array configured to detect light generated in the scintillator layer, wherein the detector array comprises a plurality of groups of photosensitive elements, each group comprising at least a first photosensitive element and a second photosensitive element; and

a lens array situated between the scintillator layer and the detector array, wherein the lens array comprises a plurality of lenses, each lens covering one of the plurality of groups of photosensitive elements.

22. The x-ray imager of claim 21 wherein the first photosensitive element in each group has a first optical path through the scintillator through the lens covering the group, and the second photosensitive element in each group has a second optical path through the scintillator through the lens covering the group;

and

optical paths of the plurality of first photosensitive elements in the plurality of groups converge in a first plane in the scintillator layer, and optical paths of the plurality of second photosensitive elements in the plurality of groups converge in a second plane in the scintillator layer.

23. The x-ray imager of claim 22 wherein each group of photosensitive elements comprises more than two photosensitive elements each having an optical path through the scintillator, and optical paths of the more than two photosensitive elements of the plurality of groups converge in more than two planes respectively in the scintillator layer.

24. The x-ray imager of claim 21 wherein the scintillator layer, the detector array, and the lens array are arranged in a configuration such that x-rays traverse the detector array before propagating in the scintillator layer.

25. The x-ray imager of claim 21 wherein the scintillator layer, the detector array, and the lens array are arranged in a configuration such that x-rays are incident on the scintillator layer before propagating in the detector array.

26. A method of acquiring x-ray images, comprising:

receiving x-rays having an energy spectrum including a first energy portion and a second energy portion by an x-ray imager comprising a scintillator layer, a lens array and a detector array, thereby light is generated in the scintillator in a first plane and in a second plane, wherein

the detector array comprises a plurality of groups of photosensitive elements, each group comprising at least a first photosensitive element and a second photosensitive element; and

the lens array comprises a plurality of lenses each lens covering one of the plurality of groups of photosensitive elements;

the first photosensitive element in each group has a first optical path through the scintillator through the lens covering the group, the second photosensitive element in each group has a second optical path through the scintillator through the lens covering the group, and optical paths of the plurality of first photosensitive elements in the plurality of groups converge in a first plane in the scintillator layer, and optical paths of the plurality of second photosensitive elements in the plurality of groups converge in a second plane in the scintillator layer;

collecting image signals using the detector array;

constructing a first image pixel using data from the plurality of first photosensitive elements of the plurality of groups.

27. The method of claim 26 further comprising the step of constructing a second image pixel using data from the plurality of second photosensitive elements of the plurality of groups.

28. The method of claim 27 further comprising the step of computing a third image pixel using the constructed first and second image pixels.

29. The method of claim 28 wherein the x-rays received by the x-ray imager is in a single pulse.

30. The method of claim 26 wherein each group of photosensitive elements comprises more than two photosensitive elements each having an optical path through the scintillator, and optical paths of the more than two photosensitive elements of the plurality of groups converge in more than two planes respectively in the scintillator layer.