High resolution, multiple-energy linear sweep detector for x-ray imaging

• US 5,548,123 A
• Filed: 12/06/1994
• Issued: 08/20/1996
• Est. Priority Date: 12/06/1994
• Status: Expired due to Fees

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Goodman, Claude A., Perez-Mendez, Victor
• Primary Examiner(s): Willis, Davis L.
• Assistant Examiner(s): HANIG, RICHARD E
• Application Number:
  US08/350,854
• Time in Patent Office: 623 Days
• Field of Search: 250/370.06, 250/370.11, 250/370.09, 378/5
• US Class Current: 250/370.11
• CPC Class Codes: G01T 1/20181 Stacked detectors, e.g. for measuring energy and positional information using a combination of different types of scintillation detectors, e.g. phoswich detectors, G01T1/2008
• CPC Class Codes: G01T 1/20186 Position of the photodiode with respect to the incoming radiation, e.g. in the front of, below or sideways the scintillator

Abstract

Apparatus for generating plural electrical signals in a single scan in response to incident X-rays received from an object. Each electrical signal represents an image of the object at a different range of energies of the incident X-rays. The apparatus comprises a first X-ray detector, a second X-ray detector stacked upstream of the first X-ray detector, and an X-ray absorber stacked upstream of the first X-ray detector. The X-ray absorber provides an energy-dependent absorption of the incident X-rays before they are incident at the first X-ray detector, but provides no absorption of the incident X-rays before they are incident at the second X-ray detector. The first X-ray detector includes a linear array of first pixels, each of which produces an electrical output in response to the incident X-rays in a first range of energies. The first X-ray detector also includes a circuit that generates a first electrical signal in response to the electrical output of each of the first pixels. The second X-ray detector includes a linear array of second pixels, each of which produces an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies. The second X-ray detector also includes a circuit that generates a second electrical signal in response to the electrical output of each of the second pixels.

Claims

1. Apparatus for generating, in a single scan and in response to incident X-rays received from an object, plural electrical signals, each electrical signal representing an image of the object at a different range of energies of the incident X-rays, the apparatus comprising:

a first X-ray detector, including;

a first light detector having a first surface disposed substantially parallel to the incident X-rays, wherein the first light detector has a linear array of first pixels, each of the first pixels producing an electrical output in response to the incident X-rays in a first range of energies,

a first scintillator layer comprising columns of scintillator material grown on the first surface, and

means for generating a first electrical signal in response to the electrical output of each of the first pixels;

a second X-ray detector stacked upstream of the first X-ray detector, the second X-ray detector including;

a second light detector having a second surface disposed substantially parallel to the incident X-rays, wherein the second light detector has a linear array of second pixels, each of the second pixels producing an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies,

a second scintillator layer comprising columns of scintillator material grown on the second surface, and

means for generating a second electrical signal in response to the electrical output of each of the second pixels, wherein the first scintillator layer provides an energy-dependent absorption of the incident X-rays before said incident X-rays are incident at the second scintillator layer.

2. The apparatus of claim 1, wherein the first light detector and the second light detector each include an amorphous semiconductor material.

3. The apparatus of claim 2, wherein:

the first scintillator layer comprises plural columns of the scintillator material formed substantially perpendicularly to the first surface, at least one column of the scintillator material being formed overlying each of the first pixels; and

the second scintillator layer comprises plural columns of the scintillator material formed substantially perpendicularly to the second surface, at least one column of the scintillator material being formed overlying each of the second pixels.

4. The apparatus of claim 1, wherein the first scintillator layer is separated by a groove from the second scintillator layer, the apparatus also including:

an X-ray absorbing foil mounted in the groove.

5. The apparatus of claim 1, wherein the first light detector and the second light detector are formed side-by-side along a single light detector layer having a photon receiving surface, the first surface is a first portion of the photon receiving surface, the second surface is a second portion of the photon receiving surface, the first pixels and the second pixels are formed in parallel linear arrays along the single light detector layer, the first scintillator layer and the second scintillator layer are portions of a larger scintillator layer, the first scintillator layer is a portion of the larger scintillator layer which overlies the first portion of the photon receiving surface, and the second scintillator layer is another portion of the larger scintillator layer which overlies the second portion of the photon receiving surface.

6. The apparatus of claim 1, wherein the scintillator material is thallium-activated cesium iodide.

7. The apparatus of claim 6, wherein each of the first scintillator layer and the second scintillator layer includes columns of thallium-activated cesium iodide.

8. Apparatus for generating, in a single scan and in response to incident X-rays received from an object, plural electrical signals, each electrical signal representing an image of the object at a different range of energies of the incident X-rays, the apparatus comprising:

a first X-ray detector, including;

a first light detector having a first surface disposed substantially perpendicularly to the incident X-rays and including a linear array of first pixels formed in the first surface, and a first scintillator layer comprising columns of scintillator material grown on the first surface, each of the first pixels producing an electrical output in response to the incident X-rays in a first range of energies, and

means for generating a first electrical signal in response to the electrical output of each of the first pixels; and

a second X-ray detector stacked upstream of the first X-ray detector, the second X-ray detector including;

a second light detector having a first surface disposed substantially perpendicularly to the incident X-rays and including a linear array of second pixels formed in the second surface, and a second scintillator layer comprising columns of the scintillator material grown on the second surface, the second scintillator layer providing an energy-dependent absorption of the incident X-rays before said incident X-rays are incident at the first X-ray detector, each of the second pixels generating an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies, and

means for generating a second electrical signal in response to the electrical output of each of the second pixels.

9. The apparatus of claim 8, wherein:

the first scintillator layer comprises plural columns of the scintillator material formed substantially perpendicularly to the surface of the first light detector, at least one column of said scintillator material being formed overlying each of the first pixels; and

the second scintillator layer comprises plural columns of said scintillator material formed substantially perpendicularly to the surface of the second light detector, at least one column of said scintillator material being formed overlying each of the second pixels.

10. The apparatus of claim 9, wherein the first light detector and the second light detector each include an amorphous semiconductor material.

11. The apparatus of claim 8, wherein the scintillator material is thallium-activated cesium iodide.

12. Apparatus for generating, in a single scan and in response to incident X-rays received from an object, plural electrical signals, each electrical signal representing an image of the object at a different range of energies of the incident X-rays, the apparatus comprising:

a light detector layer having a surface disposed substantially parallel to the incident X-rays;

a scintillator layer comprising columns of scintillator material grown on the surface; and

a first X-ray detector and a second X-ray detector formed side-by-side in the light detector layer and the scintillator layer;

the first X-ray detector including;

a linear array of first pixels formed in a first portion of the light detector layer, and a first portion of the scintillator layer overlaying the first pixels, each of the first pixels generating an electrical output in response to the incident X-rays in a first range of energies; and

means for generating a first electrical signal in response to the electrical output of each of the first pixels, and

the second X-ray detector including;

a linear array of second pixels formed in a second portion of the light detector layer, the linear array of second pixels being disposed parallel to and upstream of the linear array of first pixels, and a second portion of the scintillator layer overlaying the second pixels, the second portion of the scintillator layer providing an energy-dependent absorption of the incident X-rays before said incident X-rays are incident at the first portion of the scintillator layer, each of the second pixels generating an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies; and

means for generating a second electrical signal in response to the electrical output of each of the second pixels.

13. The apparatus of claim 12, wherein the scintillator layer comprises plural columns of scintillator material formed substantially perpendicularly to the surface of the light detector layer, at least one column of scintillator material being formed on each of the first pixels and on each of the second pixels.

14. The apparatus of claim 13, wherein the light detector layer includes an amorphous semiconductor material.

15. The apparatus of claim 12, wherein:

the scintillator layer includes a groove separating the first portion from the second portion; and

the apparatus additionally comprises an X-ray absorbing foil mounted in the groove.

16. The apparatus of claim 12, wherein the first pixels and the second pixels are elongate in a direction parallel to the incident X-rays.

17. The apparatus of claim 12, wherein the scintillator material is thallium-activated cesium iodide.

18. Apparatus for generating, in a single scan and in response to incident X-rays received from an object, plural electrical signals, each electrical signal representing an image of the object at a different range of energies of the incident X-rays, the apparatus comprising:

a first X-ray detector, including;

a first light detector having a first surface disposed substantially perpendicularly to the incident X-rays, wherein the first light detector has a linear array of first pixels, each of the first pixels producing an electrical output in response to the incident X-rays in a first range of energies,

a first scintillator layer that has been grown on the first surface, and

means for generating a first electrical signal in response to the electrical output of each of the first pixels;

a second X-ray detector stacked upstream of the first X-ray detector, the second X-ray detector including;

a second light detector having a second surface disposed substantially perpendicularly to the incident X-rays, wherein the second light detector has a linear array of second pixels, each of the second pixels producing an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies,

a second scintillator layer that has been grown on the second surface, and

means for generating a second electrical signal in response to the electrical output of each of the second pixels, wherein the first scintillator layer provides an energy-dependent absorption of the incident X-rays before said incident X-rays are incident at the second scintillator layer.