X-ray tomography and laminography

• US 7,177,389 B2
• Filed: 01/07/2005
• Issued: 02/13/2007
• Est. Priority Date: 01/09/2004
• Status: Expired due to Fees

• Current Assignee: Adelphi Technology Incorporated
• Original Assignee: Adelphi Technology Incorporated
• Inventors: Gary, Charles K.
• Primary Examiner(s): Thomas; Courtney
• Application Number:
  US11/031,650
• Publication Number:
  US 20050265517A1
• Time in Patent Office: 767 Days
• Field of Search: 378 21- 27, 378/43, 378/62, 250/251, 250/505.1
• US Class Current: 378/21
• CPC Class Codes: A61B 6/00 Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment instruments measuring radiation intensity for application in the field of nuclear medicine, e.g. in vivo counting, G01T1/161; apparatus for taking X-ray photographs G03B42/02
• CPC Class Codes: A61B 6/4021 involving movement of the focal spot
• CPC Class Codes: A61B 6/4035 the source being combined with a filter or grating
• CPC Class Codes: A61B 6/4092 for producing synchrotron radiation
• CPC Class Codes: A61B 6/4488 Means for cooling A61B6/045 takes precedence
• CPC Class Codes: A61B 6/508 for non-human patients
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/044 using laminography or tomosynthesis
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]

Abstract

An apparatus for imaging objects with x rays using an x-ray tube, refractive x-ray lens and area detector. Cross sectional images of individual planes within an object are achieved through tomographic and laminographic exposure and image processing. The use of refractive x-ray lenses to achieve high resolution eliminates the need for vanishingly small microspot x-ray sources to achieve high resolution that current x-ray tomographic and laminographic systems suffer.

Claims

1. A device for tomographically imaging an object comprising:

a compound refractive lens for x-rays having a focal length f and an aperture;

an x-ray source, selected from the group consisting of an x-ray tube and a plasma x-ray source, which is oriented to direct x rays toward said compound refractive lens;

an x-ray detector located at a distance i from said compound refractive lens and positioned to receive x rays from said compound refractive lens, said x-ray detector further comprising an output which emits data signals corresponding to the x-ray intensity pattern striking the detector;

wherein the object is located at a distance o from said compound refractive lens and is illuminated by x-rays from said x-ray source that are directed toward said compound refractive lens; and

wherein

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i};<br><br>$

wherein the depth of field of the refractive lens is greater than or equal to the thickness of the volume of the object to be imaged; and

wherein the x-rays emitted from the source are collimated to eliminate x-rays that do not pass through both the object and the refractive lens while maintaining sufficient divergence to fill 20% or more of the aperture of the refractive lens;

a device that moves the object and an imaging train consisting of the x-ray source, refractive x-ray lens and detector relative to each other so that the object is imaged over a range of angles around an axis through the object perpendicular to the optical axis defined by the centers of the source, lens and detector;

an image memory that combines said detector data signals from a range of positions to form an image database that contains information sufficient to form a cross-sectional image of a cutting plane of the object.

2. A device as defined in claim 1, wherein the x-ray source emits characteristic line radiation at a wavelength such that the lens equation

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i}$

is satisfied by the positions of the object, compound refractive lens and detector.

3. A device as defined in claim 1, wherein the x rays emitted from the source are filtered to reduce the intensity of x rays emitted at wavelengths other than the useful wavelength bandpass of the refractive lens.

4. A device as defined in claim 1, wherein the x-rays are collimated and filtered by a monocapillary optic with output divergence sufficient to 20% or more of the aperture of the compound refractive lens with x-rays from each point in the object.

5. A device as defined in claim 1, wherein the x-rays are collimated and filtered by a polycapillary optic with the output divergence from any given capillary sufficient to fill the numerical aperture of the compound refractive lens and the mean direction of the radiation from each capillary directed to the center of the compound refractive lens.

6. A device as defined in claim 1, wherein the x rays are collimated and filtered by a reflective optic.

7. A device for tomographically imaging objects comprising:

a compound refractive lens for x-rays having a focal length f and an aperture;

a source that emits x-rays,

an x-ray detector located at a distance i from said compound refractive lens and positioned to receive x rays from said compound refractive lens, said x-ray detector further comprising an output which emits data signals corresponding to the x-ray intensity pattern striking the detector;

a reflective optic located between the source and object that serves to collimate and filter the radiation from the source such that the x-rays passing through the object will strike the aperture of the compound refractive lens, and with the output divergence from any given point on the reflective optic sufficient to fill 20% or more of the aperture of the compound refractive lens and with the mean reflected radiation from each point on the reflected optic directed toward the center of the lens;

wherein the object is located at a distance o from said compound refractive lens and is illuminated by x-rays from said x-ray source that are directed toward said compound refractive lens; and

wherein

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i};<br><br>$

wherein the depth of field of the refractive x-ray lens is greater than or equal to the thickness of the volume of the object to be imaged;

a device that moves the object and an imaging train consisting of the x-ray source, reflective optic, refractive x-ray lens, and detector relative to each other so that the object is imaged over a range of angles around an axis through the object perpendicular to the optical axis defined by the centers of the reflective optic output plane, compound refractive lens and detector.

an image memory that combines said detector data signals from a range of positions to form an image database that contains information sufficient to form a cross-sectional image of a cutting plane of the object.

8. A device as defined in claim 7, wherein the x-ray source emits characteristic line radiation at a wavelength such that the lens equation

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i}$

is satisfied by the positions of the object, lens and detector.

9. A device for imaging objects comprising

a compound refractive lens for neutrons having a focal length f;

a neutron source which is oriented to direct neutrons toward said compound refractive lens;

a neutron detector located at a distance i from said compound refractive lens and positioned to receive neutrons from said compound refractive lens, said neutron detector system further comprising an output which emits data signals corresponding to the neutron intensity pattern striking the detector;

wherein the object is located at a distance o from said compound refractive lens and is illuminated by neutrons from said neutron source that are directed toward said compound refractive lens; and

wherein

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i};<br><br>$

wherein the depth of field of the refractive neutron lens is greater than or equal to the thickness of the volume of the object to be imaged;

wherein the neutrons emitted from the source are collimated to eliminate a plurality of neutrons that do not pass through both the object and the lens while maintaining sufficient divergence to fill 20% or more of the aperture of the lens;

a device that moves the object and an imaging train consisting of the neutron source, refractive neutron lens and detector relative to each other so that the object is imaged over range of angles around an axis through the object perpendicular to the optical axis defined by the centers of the source, lens and detector;

an image memory that combines said detector data signals from a range of angles to form an image database which contains information sufficient to form a cross-sectional image of a cutting plane of the object.

10. A device as in claim 9, wherein the neutrons from the source are filtered to eliminate a plurality of neutrons that are outside the imaging bandpass of the refractive lens.

11. A device for laminographically imaging objects comprising:

a compound refractive lens for x-rays having a focal length f;

an x-ray source, selected from the group consisting of an x-ray tube and a plasma x-ray source, which is oriented to direct x rays toward said compound refractive lens;

an x-ray detector located at a distance i from said compound refractive lens and positioned to receive x rays from said compound refractive lens, said x-ray detector system further comprising an output which emits data signals corresponding to the x-ray intensity pattern striking the detector;

wherein the object is located at a distance o from said compound refractive lens and is illuminated by x-rays from said x-ray source that are directed toward said compound refractive lens; and

wherein

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i};<br><br>$

wherein the depth of field of the compound refractive x-ray lens is greater than or equal to the thickness of the volume of the object to be imaged;

wherein the x rays emitted from the source are collimated to eliminate a plurality of photons that do not pass through both the object and the lens while maintaining sufficient divergence to fill 20% or more of the aperture of the lens;

a device that moves the object and an imaging train, consisting of the source, refractive lens and detector, relative to each other so that the optical axis defined by the centers of the source, lens and detector precesses around a chosen axis through the object not perpendicular to the optical axis, allowing the visualization of planes in the object perpendicular to the chosen axis;

wherein said x ray detector collects data associated with the positions encountered with such precession;

an image memory that combines said detector data signals from said positions to form an image database which contains information sufficient to form a cross-sectional image of a cutting plane of the object.

12. A device as defined in claim 11, wherein the x-ray source is an x-ray tube.

13. A device as defined in claim 11, wherein the x rays emitted from the source are filtered to reduce the intensity of x rays emitted at wavelengths other than the operational wavelength bandpass of the compound refractive lens.

14. A device as defined in claim 11, wherein the x-rays are collimated and filtered by a monocapillary optic with output divergence sufficient to fill 20% or more of the aperture of the lens with x-rays from each point in the object.

15. A device as defined in claim 11, wherein the x-rays are collimated and filtered by a polycapillary optic with the output divergence from any given capillary sufficient to fill the numerical aperture of the lens and the mean direction of the radiation from each capillary directed to the center of the compound refractive lens.

16. A device as defined in claim 11, wherein the x rays are collimated and filtered by a reflective optic.

17. A device for laminographically imaging objects comprising:

a compound refractive lens for x-rays having a focal length f and an aperture;

a source that emits x-rays.

an x-ray detector located at a distance i from said compound refractive lens and positioned to receive x rays from said compound refractive lens, said x-ray detector system further comprising an output which emits data signals corresponding to the x-ray intensity pattern striking the detector;

a reflective optic located between the source and object that serves to collimate and filter the radiation from the source such that the photons passing through the object will strike the aperture of the compound refractive lens, and with the output divergence from any given point on the reflective optic sufficient to fill 20% or more of the aperture of the lens and with the mean reflected radiation from each point on the reflected optic directed toward the center of the compound refractive lens;

wherein the object is located at a distance o from said compound refractive lens and is illuminated by x-rays from said x-ray source that are directed toward said compound refractive lens; and

wherein

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i};<br><br>$

wherein the depth of field of the refractive x-ray lens is greater than or equal to the thickness of the volume of the object to be imaged;

a device that moves the object and an imaging train, consisting of the source, reflective optic, refractive lens and detector, relative to each other so that the optical axis defined by the centers of the reflective optic output plane, lens and detector, precesses around a chosen axis through the object not perpendicular to the optical axis, allowing the visualization of planes in the object perpendicular to the chosen axis.

an image memory that combines said detector data signals resulting from said precessing to form an image database that contains information sufficient to form a cross-sectional image of a cutting plane through the object.

18. A device for imaging objects comprising

a compound refractive lens for neutrons having a focal length f;

a neutron source which is oriented to direct neutrons toward said compound refractive lens;

a neutron detector located at a distance i from said compound refractive lens and positioned to receive neutrons from said compound refractive lens, said neutron detector system further comprising an output which emits data signals corresponding to the neutron intensity pattern striking the detector;

wherein the object is located at a distance o from said compound refractive lens and is illuminated by neutrons from said neutron source that are directed toward said compound refractive lens; and

wherein

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i};<br><br>$

wherein the depth of field of the compound refractive lens is greater than or equal to the thickness of the volume of the object to be imaged;

wherein the neutrons emitted from the source are collimated to eliminate a plurality of neutrons that do not pass through both the object and the lens while maintaining sufficient divergence to fill 20% or more of the aperture of the lens

a device that rotates the object or moves the source, neutron lens and detector so that an axis through the object precesses around the optical axis defined by the centers of the source, lens and detector, allowing the visualization of planes in the object perpendicular to the chosen axis;

an image memory that combines said detector data signals from said precession to form an image database which contains information sufficient to form a cross-sectional image of a cutting plane of the object.

19. A device as defined in claim 18, wherein the neutrons emitted from the source are collimated to eliminate neutrons that do not pass through both the object and the lens while maintaining sufficient divergence to fill the numerical aperture of the lens.

20. A device as defined in claim 18, wherein the neutrons emitted from the source are filtered to reduce the intensity of neutrons emitted at wavelengths other than the operational wavelength bandpass of the refractive lens.

21. An x-ray microscope for imaging an object, comprising:

a compound refractive lens for x-rays having a focal length f and an aperture;

an x-ray source, selected from the group consisting of an x-ray tube and a plasma x-ray source, which is oriented to direct x rays toward said compound refractive lens;

a reflective x-ray optic that collects x rays from the source and redirects said x rays toward the center of said compound refractive lens with a local angular divergence to the x-ray pattern from each point on the optic sufficient to fill at least 20% of the aperture of said compound refractive lens, and such that the plurality of photons passing through the object will strike the aperture of the compound refractive lens;

an x-ray detector located at a distance i from said compound refractive lens and positioned to receive x rays from said compound refractive lens, said x-ray detector system further comprising an output which emits data signals corresponding to the x-ray intensity pattern striking the detector,

wherein the object is located at a distance o from said compound refractive lens and is illuminated by x-ray from said x-ray source that are directed toward said compound refractive lens; and

wherein

$\frac{1}{f}=\frac{1}{o}+\frac{1}{i}.$