X-ray tomography and laminography

• US 20050265517A1
• Filed: 01/07/2005
• Published: 12/01/2005
• Est. Priority Date: 01/09/2004
• Status: Active Grant

• Current Assignee: Charles K. Gary
• Original Assignee: Charles K. Gary
• Inventors: Gary, Charles K.
• Granted Patent: US 7,177,389 B2
• Time in Patent Office: Days
• 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;

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

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

a device that moves the object and the 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 an 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 said compound refractive x-ray lens has a depth of field that is greater than or equal to the thickness of the volume of the object to be imaged.

3. A device as defined in claim 1, wherein the x-ray source emits characteristic line radiation at a wavelength such that lens equation (4) is satisfied by the positions of the object, compound refractive lens and detector.

4. A device as defined in claim 1, wherein the x rays emitted from the source are collimated to eliminate 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 compound refractive lens.

5. 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 compound refractive lens.

6. A device as defined in claim 1, wherein the x-rays are collimated and filtered by a monocapillary optic with output divergence sufficient to fill the field of view of the compound refractive lens.

7. 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.

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

9. A device for tomographically imaging objects comprising:

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

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 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 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

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

a device that moves the object and the 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 said range of angles to form an image database that contains information sufficient to form a cross-sectional image through a cutting plane of the object.

10. A device as defined in claim 9, wherein the depth of field of the compound refractive lens is greater than or equal to the thickness of the object to be imaged.

11. A device as defined in claim 9, wherein the x-ray source emits characteristic line radiation at a wavelength such that the lens equation (4) is satisfied by the positions of the object, lens and detector.

12. 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 x rays 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

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

a device that moves the object and the imaging train consisting of the neutron source, compound refractive 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 said range of angles to form an image database which contains information sufficient to form a cross-sectional image through a cutting plane of the object.

13. A device as in claim 12, wherein the neutrons from the source are collimated by an optic to eliminate a plurality of neutrons that pass through the object but do not pass through the compound refractive lens.

14. A device as in claim 12, wherein the neutrons from the source are filtered to eliminate a plurality of neutrons that are outside the imaging bandpass of the compound refractive lens.

15. 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-ray s from said x-ray source that are directed toward said compound refractive lens; and

wherein

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

a device that moves the object and 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, compound refractive lens and detector precesses around a chosen axis through the object not perpendicular to the optical axis, allowing the visualization of planes through the object that are perpendicular to the chosen axis;

wherein said x ray detector collects data associated with 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 through the object.

16. A device as defined in claim 15, wherein the x-ray source is an x-ray tube.

17. A device as defined in claim 15, wherein the x rays emitted from the source are collimated to eliminate photons that do not pass through both the object and the compound refractive lens while maintaining sufficient divergence to fill the numerical aperture of the compound refractive lens.

18. A device as defined in claim 15, 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.

19. A device as defined in claim 15, wherein the x-rays are collimated and filtered by a monocapillary optic with output divergence sufficient to fill the field of view of the compound refractive lens.

20. A device as defined in claim 15, 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.

21. A device as defined in claim 15, wherein the x rays are collimated and filtered by a reflective optic.

22. A device for laminographically imaging objects comprising:

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

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 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 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

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

a device that moves the object and 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 through 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.

23. 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 x rays 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

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

a device that rotates the object or moving 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 resulting from said precession to form an image database which contains information sufficent to form a cross-sectional image of a cutting plane of the object.

24. A device as defined in claim 23, 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.

25. A device as defined in claim 23, 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.

26. A device for tomographically imaging objects comprising:

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

a source that emits x-rays that then pass through the object to be imaged, wherein the divergence of x rays transmitted through each point in the object within the field of view is sufficient to fill 20% or more of the aperture of the refractive x-ray 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 s from said x-ray source that are directed toward said compound refractrive lens; and

wherein

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

a device that moves the object and the 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 range of angles around an axis through the object perpendicular to the optical axis defined by the centers of the source, compound refractive lens and detector;

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

27. A device for tomographically imaging objects comprising:

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

a source that emits x-rays that then pass through the object to be imaged, wherein the divergence of x rays transmitted through each point in the object within the field of view is sufficient to fill 20% or more of 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 s from said x-ray source that are directed toward said compound refractrive lens; and

wherein

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

a means of moving the object and 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.

an image memory that combines said detector data signals resulting 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.

28. An x-ray microscope for imaging an object, 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;

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.

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

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