In-line X-ray Optics for Tissue Differentiation
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Solution Overview
Problem
Current medical x-ray imaging technologies face limitations in differentiating tissues with small attenuation differences, such as blood vessels and soft tissues, due to inherent limitations in attenuation-based contrast, and struggle with long acquisition times and reduced dose efficiency in phase-contrast and dark-field imaging methods.
Innovation Solution
An x-ray imaging system comprising an in-line array of lenses combined with a photon-counting detector that compensates for chromatic aberration and limited coherence, allowing for simultaneous acquisition of transmission, phase-contrast, and dark-field images, and efficiently separates primary from scattered photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If attenuation-based imaging is used, then the imaging system is simple and fast, but it cannot differentiate tissues with small attenuation differences
Solution Approach 1:
The patent combines attenuation imaging, phase-contrast imaging, and dark-field imaging into a single integrated system using an in-line optics configuration. This merging allows simultaneous acquisition of multiple contrast mechanisms that differentiate tissues with small attenuation differences, while maintaining a relatively simple overall system architecture compared to separate imaging systems.
Solution Approach 2:
The in-line optics configuration serves multiple functions: it enables attenuation imaging, phase-contrast imaging, and dark-field imaging through a single optical path. This multi-functionality allows the system to differentiate various tissue types with small attenuation differences without requiring multiple separate imaging systems, thus improving measurement precision while controlling device complexity.
2Measurement precision
If phase-contrast imaging is used, then tissue differentiation improves, but acquisition time increases
Solution Approach 1:
The in-line optics configuration enables continuous acquisition of phase-contrast information along the same optical path used for attenuation imaging. By maintaining a continuous optical path and using the same detector for multiple contrast mechanisms, the system eliminates the need for separate acquisition sequences, thereby reducing total acquisition time while preserving improved tissue differentiation capability.
Solution Approach 2:
The patent merges phase-contrast imaging with attenuation imaging in a single optical path, allowing both types of information to be acquired simultaneously or in rapid succession. This combining of imaging modes reduces the total acquisition time compared to performing phase-contrast imaging as a separate, time-consuming procedure, while still providing enhanced tissue differentiation.
3Measurement precision
If anti-scatter grids are used, then scatter rejection improves, but dose efficiency decreases
Solution Approach 1:
The patent extracts scatter rejection functionality from the traditional anti-scatter grid approach and implements it through in-line optics that selectively focus primary photons while allowing scattered photons to be rejected. This extraction of the scatter rejection function from physical grids to optical focusing enables improved scatter-to-primary ratio without the dose penalty associated with grid absorption, thereby improving measurement precision while maintaining dose efficiency.
4Use of energy by moving object
If in-line x-ray optics are used, then dose efficiency improves, but chromatic aberration and limited coherence become issues
Solution Approach 1:
The patent employs photon-counting detectors that can resolve photon energy, allowing the system to select and process photons within specific energy ranges. This parameter-based selection compensates for chromatic aberration by focusing on monochromatic subsets of the polychromatic beam, and the high coherence of the in-line optics configuration maintains image quality consistency despite the polychromatic nature of the source, thereby preserving both dose efficiency and reliability.
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
This configuration improves detection and diagnosis by enhancing phase-contrast and dark-field information, reducing acquisition time, and increasing dose efficiency, while maintaining high spatial resolution and rejecting scattered photons effectively.
Implementation Method 1
X-rays refract and undergo phase shifts when propagating through material interfaces. The complex index of refraction is used to characterize different materials in terms of their attenuation and phase change properties
Implementation Method 2
The real part of the refractive index relates to the phase shift. The decrement from unity δ is very small and typically in the order of magnitude of 10^-5
Implementation Method 3
where the first term describes propagation through vacuum, the second term accounts for phase changes and the third term accounts for attenuation
Implementation Method 4
Phase-contrast imaging is based on coherent scattering, which gives rise to non-random phase changes. Coherent scattering dominates over incoherent scattering for small scattering angles
Implementation Method 5
Coherent scattering dominates over incoherent scattering for small scattering angles
Data Source
Figure 1a)~1c)
Figure 2
Figure 3
AI summary
There is provided an arrangement comprising an x-ray detector (20) arranged in conjunction with in- line x-ray focusing optics (15) configured for manipulation of x-rays in medical transmission radiography, wherein the in-line x-ray optics (15) comprises an array of lenses, in which the lenses cover parts of, or the entire, field of view, and in which the x-ray detector (20) is a photon-counting detector. Furthermore, the x-ray detector (20) is an energy-resolving detector and chromatic aberration of the lens array and/or limited coherence of the source is compensated for by the energy resolution of the energy-resolving detector, and/or the x-ray detector (20) is a depth-resolving detector and chromatic aberration of the lens array and/or limited coherence of the source (10) is compensated for by depth resolution or volumetric resolution in the detector (20).