System for non-invasive classification of different types of micro-calcifications in human tissue

Patent metadata

Field	Value
Publication number	US-9439615-B2
Application number	US-201314380817-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Feb 24, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A non-invasive method distinguishes between two types of micro-calcification by x-ray imaging in mammography. Two major types of micro-calcifications are found and confirmed by histopathology and they are correlated to benign and malignant breast lesions. Distinguishing between them non-invasively will significantly improve early breast cancer diagnosis. This is based on the fact that these two types of micro-calcifications show opposite absorption and small-angle scattering signals in x-ray imaging. The imaging system, which can record these two signals of the breast tissue simultaneously for instance, an x-ray grating interferometer, can be used to uniquely determine the micro-calcification type. This is expected to be used in mammography to improve early breast cancer diagnosis, increase diagnosis accuracy and decrease the biopsy rate.

First claim

The invention claimed is:

1. A system for a non-invasive classification of different types of micro-calcifications in human tissue by combining an absorption signal and a small-angle scattering signal, the system comprising:
a set-up for recording the absorption signal and the small-angle scattering signal; and
signal processing means configured to analyze at least one pair of micro-calcifications, an analysis based on different types of micro-calcifications having opposite absorption and small angle scattering signals, wherein, one type gives a weaker absorption signal but a stronger small-angle scattering signal than the other type or vice-versa.

2. The system according to claim 1 ,
wherein a signal pair (t 1 ,t 2 ) is assigned to a pair of micro-calcifications, where t 1 ,t 2 ⊂{+,−} and t 1 and t 2 represent a relative signal strength of the absorption signal and the small angle scattering signal, respectively, wherein “+” means a signal is stronger, “−” means the signals is weaker; and
further comprising an evaluator module disposed in said signal processing means for identifying if two signal pairs constitute a combination of (+,−) and (−,+), which yields that the two signal pairs belong to different types of micro-calcifications wherein a micro-calcification signed to (−,+) is determined to be more likely a type I micro-calcification whereas (+,−) indicates that the micro-calcification is determined to be more likely a type II micro-calcification.

3. The system according to claim 1 , wherein said signal processing means calculates a ratio r of the absorption signal and the small-angle scattering signal of the micro-calcification to decouple a thickness parameter and identify micro-calcification types I and II, wherein

r
=

⁢

AC
SC

=

⁢

μ
_

·
L

c
⁢

S
_

·
L

=

⁢

μ
_

c
⁢

S
_

,

where
AC is the absorption signal, AC=∫ 0 L μ(l)dl= μ ·L;
SC is the small-angle scattering signal, SC=c∫ 0 L S(l)dl=cS·L;
L is a thickness of a specimen;
μ is an attenuation coefficient;
S is a generalized scattering parameter;
c is a constant decided by geometry and system parameters of said set-up; and
further using an predetermined threshold t that will sort out if,

{

r
<
t

,

one
⁢

⁢
type
⁢

⁢
of
⁢

⁢
the
⁢

⁢
micro
⁢

-

⁢
calcification

r
>
t

,

another
⁢

⁢
type
⁢

⁢
of
⁢

⁢
the
⁢

⁢
micro
⁢

-

⁢
calcification

.

4. The system according to claim 3 , wherein when signal data is obtained with multi-modality computed tomography, said signal processing means reconstructs tomograms of absorption information and small-angle scattering information from projection and the attenuation coefficient μ and the generalized scattering parameter S are obtained directly, wherein the absorption information and the small-angle scattering information are also opposite for two types of the micro-calcifications.

5. The system according to claim 1 , wherein the absorption signal and small-angle scattering signal are obtained from a configuration outputting x-rays, for obtaining quantitative x-ray images from a sample, said configuration including:
an X-ray source;
said setup having at least two gratings;
a position-sensitive detector with spatially modulated detection sensitivity having a number of individual pixels;
means for recording images of said position-sensitive detector;
said signal processing means having an evaluator module enabled to evaluate intensities for each pixel in a series of the image

Assignees

• Scherrer Inst Paul

Inventors

• Stampanoni Marco
• Wang Zhentian

Classifications

• G16H50/30

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

• G06T12/10

  Image preprocessing, e.g. calibration, positioning of sources or scatter correction · CPC title

• G06T2207/10116

  X-ray image · CPC title

• G06T7/0012

  Biomedical image inspection · CPC title

• A61B6/4291

  the detector being combined with a grid or grating · CPC title