Imaging method based on attenuation, refraction and ultra-small-angle scattering of x-rays

• US 20040258202A1
• Filed: 06/17/2003
• Published: 12/23/2004
• Est. Priority Date: 06/17/2003
• Status: Active Grant

• Current Assignee: Brookhaven Science Associates, LLC (Government of the United States of America), Illinois Institute of Technology
• Original Assignee: Illinois Institute of Technology
• Inventors: Zhong, Zhong, Wernick, Miles N., Chapman, Leroy Dean, Oltulu, Oral
• Granted Patent: US 6,947,521 B2
• Time in Patent Office: Days
• US Class Current: 378/70
• CPC Class Codes: A61B 6/4092 for producing synchrotron radiation
• CPC Class Codes: A61B 6/483 involving scattered radiation
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography
• CPC Class Codes: A61B 6/583 using calibration phantoms
• CPC Class Codes: G01N 23/20 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials

Abstract

A method for detecting an image of an object by measuring the intensity at a plurality of positions of a transmitted beam of x-ray radiation emitted from the object as a function of angle within the transmitted beam. The intensity measurements of the transmitted beam are obtained by a crystal analyzer positioned at a plurality of angular positions. The plurality of intensity measurements are used to determine the angular intensity spectrum of the transmitted beam. One or more parameters, such as an attenuation property, a refraction property and a scatter property, can be obtained from the angular intensity spectrum and used to display an image of the object.

Claims

1. A method for detecting an image of an object using at least one x-ray beam, the method comprising:

transmitting the at least one x-ray beam through a first view of the object and emitting from the object at least one transmitted beam;

directing the at least one transmitted beam at an analyzer;

positioning the analyzer at more than two angular positions and measuring an intensity of each said transmitted beam at each of the angular positions;

obtaining at least one parameter of the object from the intensity measurements at the more than two angular positions; and

using the at least one parameter to display the image of the object.

2. The method according to claim 1, wherein the at least one parameter includes at least one of an attenuation property, a refraction property and a scatter property of the object.

3. The method according to claim 1, further comprising preparing the at least one x-ray beam by diffraction from a monochromator.

4. The method according to claim 1, wherein the object is moved with respect to the analyzer and the image of the object is displayed at a plurality of second views of the object.

5. The method according to claim 1, wherein the analyzer includes a crystal.

6. The method according to claim 1, further comprising:

obtaining at least one parameter of a measured angular intensity spectrum;

obtaining at least one parameter of a rocking curve of an analyzer system;

subtracting the parameter of the rocking curve from the parameter of the measured intensity spectrum to obtain the parameter of the object.

7. The method according to claim 1, further comprising:

determining an estimated angular intensity spectrum as a function of a sensitivity of an analyzer system;

wherein the at least one parameter of the object is obtained from the estimated angular intensity spectrum.

8. The method according to claim 7, wherein the sensitivity of the analyzer is a rocking curve of the analyzer system.

9. The method according to claim 8, wherein a convolution integral is derived between the true angular intensity spectrum and the rocking curve.

10. The method according to claim 9, wherein a deconvolution operation inverts an effect of the convolution integral.

11. The method according to claim 10, wherein the estimated angular intensity spectrum is determined by numerically computing the deconvolution operation.

12. The method according to claim 11, wherein the at least one parameter includes at least one of an attenuation property, a refraction property and a scatter property of the object.

13. The method according to claim 10, wherein an estimated angular intensity spectrum is determined indirectly by postulating a model of the measured angular intensity spectrum a priori and by estimating the at least one parameter of the model.

14. The method of claim 1, wherein the parameter of the object is a scatter property, and further comprising:

positioning the analyzer at more than two angular positions and measuring an intensity of each said transmitted beam at each of the angular positions, wherein one of the angular positions is at a peak of the rocking curve of an analyzer system;

determining an attenuation parameter from at least two of the other more than two intensity measurements; and

subtracting the attenuation parameter from the intensity measurement measured at the rocking curve peak to obtain a scatter parameter of the object.

15. The method according to claim 1, wherein each said parameter is displayed as one of a monochrome image and a pseudocolor image.

16. The method according to claim 1, wherein the image is displayed in two dimensions.

17. The method according to claim 1, wherein the image is displayed in three dimensions.

18. The method according to claim 1, wherein the image is displayed as a computed tomographic image.

19. The method according to claim 1, further comprising:

obtaining more than one parameter from the intensity measurements; and

classifying all or part of the object into different categories of tissues or materials based on the obtained parameters.

20. The method of claim 19, further comprising classifying the tissue or material of the object by statistical pattern recognition of the obtained parameters.

21. The method according to claim 19, further comprising calculating a ratio value of at least two of the parameters and classifying the tissue or material of the object by the ratio value.