Quantitative X-ray radiology using the absorption and scattering information

Patent metadata

Field	Value
Publication number	US-9700275-B2
Application number	US-201414890006-A
Country	US
Kind code	B2
Filing date	Apr 25, 2014
Priority date	May 10, 2013
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A quantitative radiographic method uses X-ray imaging. The method uses a ratio of the absorption signal and the (small-angle) scattering signal (or vice-versa) of the object as a signature for the materials. The ratio image (dubbed R image) is independent from the thickness of the object in a wide sense, and therefore can be used to discriminate materials in a radiographic approach. This can be applied to imaging systems, which can record these two signals from the underlying object (for instance, an X-ray grating interferometer). Possible applications could be in material science, non-destructive testing and medical imaging. Specifically, the method can be used to estimate a volumetric breast density. The use of the R image and the corresponding algorithm are also presented hereafter.

First claim

The invention claimed is:

1. A method for quantitative radiology of a sample, which comprises the steps of:
determining a material or material composition of the sample via a radiographic approach by using a ratio of an absorption signal and a small-angle scattering signal of the sample, the absorption signal and the small-angle scattering signal are obtained from an X-ray investigation based on a grating-based interferometer, analyzer-crystal-based imaging, coded aperture imaging or an imaging technique that is enabled to record both absorption signals and small-angle scattering signals.

2. The method according to claim 1 , wherein the absorption signal T and the small-angle scattering signal S of the sample being a single material sample are expressed by:

T
=

-

ln
⁡

(

I

I
0

)

=

∫
l

⁢

μ
eff

⁡

(

ɛ
_

,
l

)

⁢

⁢

ⅆ
l

≈

μ
eff

⁡

(

ɛ
_

)

⁢

⁢
L

S
=

σ
2

=

∫
l

⁢

s
eff

⁡

(

ɛ
_

,
l

)

⁢

⁢

ⅆ
l

≈

s
eff

⁡

(

ɛ
_

)

⁢

⁢
L

,

where μ eff and s eff are an effective attenuation coefficient and effective generalized scattering parameter of the sample at a mean energy of ε ;
σ 2 is a second moment of a scattering angle distribution of an outgoing beam;
l is along a path of an X-ray beam and L is total thickness of the sample; and
a ratio image, dubbed R image, is defined by:

R
=

T
S

=

μ
eff

⁡

(

ɛ
_

)

⁢
L

s
eff

⁡

(

ɛ
_

)

⁢
L

=

μ
eff

⁡

(

ɛ
_

)

s
eff

⁡

(

ɛ
_

)

.

3. The method according to claim 1 , wherein the sample is a breast and a volumetric breast density is estimated using the R image of the breast.

Assignees

• Scherrer Inst Paul

Inventors

• Stampanoni Marco
• Wang Zhentian

Classifications

• A61B6/4035

  the source being combined with a filter or grating · CPC title

• A61B6/5217

  extracting a diagnostic or physiological parameter from medical diagnostic data · CPC title

• A61B6/484

  involving phase contrast X-ray imaging · CPC title

• G16H50/30

  for calculating health indices; for individual health risk assessment · CPC title

• G01N23/083

  the radiation being X-rays · CPC title