X-ray Grating Dark-Field Imaging System for Ultrafine Structure Detection

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Solution Overview

Problem

Hard x-ray dark-field imaging technology is hindered by difficulties in manufacturing optical elements, low sensitivity, long imaging times, and limited applications due to reliance on synchronous radiation sources, which restrict its use in medical and industrial fields despite its capability to distinguish ultrafine structures.

Innovation Solution

A classic optics-based x-ray grating dark-field imaging system using two absorbing gratings and a detector to derive a quantitative relationship between the second moment of scattering distribution and contrast ratio, enabling reconstruction of scattering information through a traditional linear CT reconstruction algorithm, applicable to both coherent and incoherent x-ray sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If synchronous radiation source is used for hard x-ray dark-field imaging, then imaging capability for ultrafine structures is improved, but device volume increases, cost increases, and field of view decreases

Engineering Contradiction:
Improveimaging capability for ultrafine structuresVSAvoiddevice volume
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces gratings as intermediary elements that mediate between the x-ray source and detector. These gratings enable dark-field imaging by modulating the x-ray beam based on scattering patterns, allowing the use of compact synchronous radiation sources rather than requiring large-scale facilities. The gratings act as the key intermediary component that makes ultrafine structure imaging possible with smaller devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameters of the synchronous radiation source, operating it in a storage ring mode rather than requiring a large linear accelerator. This parameter change allows the system to achieve the necessary x-ray brightness for dark-field imaging while maintaining a more compact device footprint and reducing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If synchronous radiation source is used for hard x-ray dark-field imaging, then imaging capability for ultrafine structures is improved, but imaging time increases

Engineering Contradiction:
Improveimaging capability for ultrafine structuresVSAvoidimaging time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs periodic phase-stepping motion of the gratings to modulate the x-ray beam and encode scattering information. By moving the gratings through a series of discrete positions in a periodic cycle, the system efficiently extracts dark-field signals from the x-ray images, reducing the total imaging time required to achieve ultrafine structure resolution.

Inventive Principle:
Principle #19Periodic action

3Area of stationary object

If grating-based dark-field imaging is implemented, then field of view increases and cost decreases, but manufacturing precision of optical elements becomes more critical

Engineering Contradiction:
Improvefield of viewVSAvoidmanufacturing precision of gratings
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent segments the optical system into multiple discrete grating elements rather than requiring a single large precision optic. By dividing the imaging function across several smaller grating components, the system achieves a large field of view while each individual grating element can be manufactured with feasible precision tolerances. The gratings are arranged in a segmented configuration that collectively provides the desired imaging performance.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables high-resolution imaging of internal ultrafine structures, improving upon traditional bright-field and phase contrast imaging by providing superior image quality for cartilage tissue and early breast cancer diagnostics, with a larger field of view and reduced costs, facilitating broader applications in medical and industrial contexts.

Implementation Method 1

The hard x-ray dark-field imaging technology performs the imaging of the internal structure of the substance based on a difference in scattering capability of the substance for x-rays

Methodology Applied
Scientific EffectScattering: Scattering

Implementation Method 2

two absorbing gratings (i.e. first and second absorbing gratings G1 and G2), and a detector, which are orderly positioned in a propagation direction of the x-rays

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP2453226B1X-ray dark-field imaging system and method
Publication Date: 2016.10.26 NUCTECH CO LTD
  • EP2453226B1 patent drawingFigure 1~2
  • EP2453226B1 patent drawingFigure 3(a)~4(c)
  • EP2453226B1 patent drawingFigure 5

AI summary

An x-ray imaging technology, performing an x-ray dark-field CT imaging of an examined object using an imaging system, which comprises an x-ray source, two absorbing gratings G1 and G2, an x-ray detector, a controller and a data processing unit, comprising the steps of: emitting x-rays to the examined object; enabling one of the two absorbing gratings G1 and G2 to perform phase stepping motion within at least one period range thereof; where in each phase stepping step, the detector receives the x-ray and converts it into an electric signal; wherein through the phase stepping of at least one period, the x-ray intensity at each pixel point on the detector is represented as an intensity curve; calculating a second moment of scattering angle distribution for each pixel, based on a contrast of the intensity curve at each pixel point on the detector and an intensity curve without presence of the examined object; taking images of the object at various angles, then obtaining an image with scattering information of the object in accordance with a CT reconstruction algorithm.