# US 10,117,629 B2 · High energy grating techniques

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- Number: US 10,117,629 B2
- Document ID: US10117629B2
- Status: Granted
- Kind: B2
- Application number: 14/958,882
- Filed: 2015-12-03
- Published: 2016-06-09
- Granted: 2018-11-06
- Earliest claimed: 2014-12-03
- Assignees: Board of Supervisors of Louisiana State University and Agricultural and Mechanical College
- Applicants: Board of Supervisors of Louisiana State University and Agricultural and Mechanical College
- Inventors: Leslie G. Butler; Kyungmin Ham; Warren W. Johnson
- Web page: https://patentgrep.com/patent/US10117629B2

## CPC

- A61B 6/484: {involving phase contrast X-ray imaging}
- A61B 6/032: {Transmission computed tomography [CT]}
- A61B 6/4291: {the detector being combined with a grid or grating}
- G01N 23/041: Phase-contrast imaging, e.g. using grating interferometers
- G01N 23/20075: {by measuring interferences of X-rays, e.g. Borrmann effect}
- G01N 2223/401: image processing
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Imaging techniques that may be used in applications such as differential phase contrast imaging are disclosed that include, for example, configuring a beam source and a beam detector such that a beam connects the two, positioning an object, a phase grating and an analyzer grating in the beam path, producing multiple data sets based on various analyzer grating positions, and conducting a regression analysis using a predetermined function having a set of fitting coefficients to establish those fitting coefficients. In those techniques, the fitting coefficients may be used to characterize a set of interference properties associated with the object.

## Claims

### Claim 1

An imaging technique comprising:
a) providing a beam source;
b) providing a beam detector;
c) configuring the beam source and the beam detector such that a beam path connects the beam source and the beam detector;
d) positioning an object in the beam path;
e) positioning a phase grating in the beam path;
f) positioning an analyzer grating in a first position in the beam path;
g) projecting a first beam along the beam path thereby producing a first data set;
h) moving the analyzer grating from the first position to a second position;
i) projecting a second beam along the beam path thereby producing a second data set;
j) moving the analyzer grating from the second position to a third position;
k) projecting a third beam along the beam path thereby producing a third data set;
l) conducting a regression analysis fitting pixel data from a group of data sets comprising the first data set, the second data set and the third data set to a predetermined function to establish a set of fitting coefficients;
m) wherein the set of fitting coefficients characterize a set of interference properties associated with the object;
n) wherein the predetermined function is dependent on the analyzer grating position; and
o) wherein the predetermined function contains sinusoidal functions;
p) wherein the fitting of pixel data occurs based on the relationship expressed in the equation:
c
^
g
⁢
⁢
p
=
∑
μ
=
1
n
⁢
⁢
B
g
⁢
⁢
p
⁢
a
μ
⁢
⁢
p
q) wherein crjν is an expected exposure based on grating position;
r) wherein B is a fitting function matrix that is a M×n matrix wherein M is a number of exposure steps and g is an exposure step number;
s) wherein a is a matrix containing the set of fitting coefficients;
t) wherein n is an integer that is at least 3 and
u) wherein y is a pixel number.

### Claim 2 (depends on 1)

The imaging technique of claim 1 further comprising preparing a differential phase contrast image based on a set of results from the regression analysis.

### Claim 3 (depends on 1)

The imaging technique of claim 1 wherein the first beam has a spatially-periodic intensity at the beam detector.

### Claim 4 (depends on 1)

The imaging technique of claim 1 wherein the object comprises human tissue.

### Claim 5 (depends on 1)

The imaging technique of claim 1 wherein the predetermined function has a set of basis vectors.

### Claim 6 (depends on 1)

The imaging technique of claim 1 wherein the phase grating is a spatially periodic array of beam transmitting apertures and wherein the phase grating comprises planar structures oriented parallel to the beam path.

### Claim 7 (depends on 1)

The imaging technique of claim 1 wherein the first beam is a neutron beam.

### Claim 8 (depends on 1)

The imaging technique of claim 1 wherein the first beam is an x-ray beam.

### Claim 9 (depends on 1)

The imaging technique of claim 1 wherein the predetermined function contains sine and cosine terms.

### Claim 10 (depends on 1)

The imaging technique of claim 1 wherein the regression analysis occurs on a pixel by pixel basis.

### Claim 11 (depends on 1)

The imaging technique of claim 1 wherein the analyzer grating is a periodic structure.

### Claim 12 (depends on 1)

The imaging technique of claim 1 wherein the phase grating is a periodic structure.

### Claim 13 (depends on 1)

The imaging technique of claim 1 wherein the first beam sequentially passes through the object, then through the phase grating and then through the analyzer grating.

### Claim 14 (depends on 1)

The imaging technique of claim 1 wherein the phase grating is constructed of a material that absorbs the beam.

### Claim 15 (depends on 1)

The imaging technique of claim 1 wherein a first grating step distance representing the distance between the first position and the second position is different than a second grating step distance representing the distance between the second position and the third position.

### Claim 16 (depends on 1)

The imaging technique of claim 1 wherein the analyzer grating has an analyzer grating period and a first grating step distance representing the distance between the first position and the second position that is less than the analyzer grating period.

### Claim 17

An imaging technique comprising:
a) providing a beam source;
b) providing a beam detector;
c) configuring the beam source and the beam detector such that a beam path connects the beam source and the beam detector;
d) positioning an object in the beam path;
e) positioning a phase grating in the beam path;
f) positioning an analyzer grating in a first position in the beam path;
g) projecting a first beam along the beam path thereby producing a first data set;
h) moving the analyzer grating from the first position to a second position;
i) projecting a second beam along the beam path thereby producing a second data set;
j) moving the analyzer grating from the second position to a third position;
k) projecting a third beam along the beam path thereby producing a third data set;
l) conducting a regression analysis fitting pixel data from a group of data sets comprising the first data set, the second data set and the third data set to a predetermined function to establish a set of fitting coefficients;
m) wherein the set of fitting coefficients characterize a set of interference properties associated with the object;
n) wherein the predetermined function is dependent on the analyzer grating position;
o) wherein the fitting of pixel data occurs based on the relationship expressed in the equations:
a=G*C and G=(Br·B)˜1▪Br;
p) wherein a is a matrix containing the set of fitting coefficients;
q) wherein B is a fitting function matrix that is a M×n matrix;
r) wherein c is a M×N matrix wherein M is a number of exposure steps and wherein N is a number of pixels in a captured image from the first data set;
s) wherein n is an integer that is at least 3;
t) wherein G is a fitted M×N matrix and
u) wherein superscript T indicates the matrix transpose.

### Claim 18 (depends on 17)

The imaging technique of claim 17 further comprising preparing a differential phase contrast image based on a set of results from the regression analysis.

### Claim 19 (depends on 17)

The imaging technique of claim 17 wherein the predetermined function contains sinusoidal functions.

### Claim 20 (depends on 17)

The imaging technique of claim 17 wherein the predetermined function has a set of basis vectors.