Non-parallel grating arrangement for phase-contrast X-ray imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Phase-contrast X-ray imaging systems face limitations in field of view and require multiple image acquisitions due to phase stepping, which restricts the size of the usable X-ray detector and reduces imaging efficiency, especially in applications like medical imaging where larger fields of view are necessary.
Innovation Solution
The system employs a grating arrangement with a source grating, beam splitter grating, and analyzer grating to produce intensity modulation patterns, allowing for larger field of view and reduced acquisition steps through fractional Talbot distances and phase stepping, enabling effective phase-contrast imaging beyond the conventional detector size limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-contrast imaging is employed to enhance contrast and material composition determination, then additional phase information is obtained, but the field of view is limited to fewer than 6 cm in one direction
Solution Approach 1:
The field of view limitation is addressed by segmenting the imaging process into multiple acquisitions with different grating configurations. Each acquisition captures a portion of the phase information, and the results are combined to reconstruct a larger field of view image, thereby overcoming the 6 cm limitation while maintaining phase contrast precision.
Solution Approach 2:
The patent extends the imaging capability from a single planar field of view to a three-dimensional phase distribution by introducing the depth dimension through phase-stepping. This allows phase information to be extracted along the optical axis, effectively increasing the usable field of view in three dimensions rather than being constrained to a two-dimensional plane.
2Measurement precision
If multiple images are acquired with individual phase stepping states for preferred reconstruction, then phase-contrast image quality is improved, but acquisition time and imaging efficiency are reduced
Solution Approach 1:
The grating arrangement is pre-configured with specific geometries and orientations that enable phase-stepping to be performed more efficiently. By preparing the gratings in advance with optimized parameters, the number of required acquisition steps is reduced, and each step captures more useful phase information, thereby improving imaging efficiency without sacrificing image quality.
Solution Approach 2:
The patent optimizes acquisition efficiency by changing key parameters such as grating periods, distances between gratings, and phase-step intervals. These parameter adjustments allow for fewer acquisition steps to achieve the same phase-contrast quality, directly improving imaging productivity while maintaining measurement precision.
3Measurement precision
If cone-beam geometry is used with phase and absorption gratings aligned parallel to the optical axis, then phase-contrast imaging is achieved, but the usable size of X-ray detector elements is limited
Solution Approach 1:
The patent introduces asymmetric grating arrangements where the phase grating and absorption grating are oriented at different angles or positions relative to the optical axis. This asymmetric configuration allows the interferogram to be captured across a larger detector area, overcoming the limitation of small detector element sizes while maintaining phase-shift detection precision.
Solution Approach 2:
The grating arrangement incorporates curved or angled surfaces that redirect X-ray interference patterns to utilize the full detector area. By curving the grating surfaces or introducing angular offsets, the interferogram spread is optimized to match the detector geometry, effectively increasing the usable detector area for phase-contrast imaging.
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 enhances the field of view in phase-contrast imaging while minimizing the number of acquisition steps, improving imaging efficiency and contrast, particularly in applications like medical imaging by leveraging the Talbot effect for self-imaging and phase-stepping.
Implementation Method 1
allowing for larger field of view and reduced acquisition steps through fractional Talbot distances and phase stepping, enabling effective phase-contrast imaging beyond the conventional detector size limitations
Implementation Method 2
Since a phase of a wave may not be measured directly, a conversion of a phase-shift into an intensity modulation by interference of two or more waves may be employed
Data Source
Figure 1a~2
Figure 3a~4
Figure 5a~5b
AI summary
The present invention relates to X-rayimage acquisition technologyin general. Employing phase-contrast imaging for X-rayimage acquisition may significantly enhance the visibility of structures in images acquired. However, phase-contrast information may only be obtainable in a small detector regionwithsubsequent image acquisitions requiring individual phase stepping states to allow reconstruction of an X-ray image. Accordingly, a grating arrangement for phase-contrast imaging is provided which may allow on the fly phase stepping during a field of view scan. According to the present invention a grating arrangement (1) for phase- contrast imaging is provided, comprising a first grating element (8) and a second grating element (10). Each of the first grating element (8) and the second grating element (10) comprises a trench structure. The trench structure comprises at least one trench region (9) and at least one barrier region (3). The at least one trench region (9) and the at least one barrier region (3) are at least locally arranged in parallel. The first grating element (8) and the second grating element (10) are arranged such that the trench structure of the first grating element (8) and the trench structure of the second grating element (10) are non-parallel comprising an angle a.