Talbot Interferometer Phase Grid Rotation for Complete Refraction Angle Measurement
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Solution Overview
Problem
Existing differential phase-contrast computed tomography (DPC-CT) methods using X-ray radiation can only measure one component of the angle of refraction, limiting the reconstruction of the refractive index and phase shift gradient, especially when using one-dimensional phase grids.
Innovation Solution
The use of a Talbot interferometer with one-dimensional phase grids allows for the measurement of the complete angle of refraction by performing phase scans with the phase grid and readout arrangement oriented at different angles relative to the examination object, enabling the determination of two linearly independent directional derivatives for tomographic reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one-dimensional phase grids are used in differential phase-contrast computed tomography, then the device complexity is reduced, but the measurement precision is worsened because only one component of the angle of refraction can be measured
Solution Approach 1:
The patent applies the dynamics principle by rotating the phase grid around the X-ray beam axis during the scanning process. This dynamic reorientation allows a single one-dimensional phase grid to measure refraction angle components in multiple directions sequentially, thereby achieving complete gradient information without requiring multiple fixed grids or complex multi-dimensional detector arrangements.
2Measurement precision
If multiple measurements with different grid orientations are performed, then the measurement precision is improved by determining the complete angle of refraction, but the loss of time increases due to multiple scanning operations
Solution Approach 1:
The patent resolves the time loss issue by implementing continuous rotation of the phase grid during a single scanning operation. Instead of performing separate measurements with statically positioned grids, the dynamic rotation enables all necessary orientation data to be collected in one continuous scan, significantly reducing the total measurement time while maintaining complete gradient information acquisition.
Solution Approach 2:
The patent applies the continuity principle by ensuring that the phase grid rotation and X-ray scanning proceed simultaneously and continuously. This integrated approach eliminates idle time between measurements and ensures that data collection is uninterrupted, thereby minimizing loss of time while maintaining measurement precision.
3Ease of operation
If one-dimensional phase grids with fixed orientation are used, then the ease of operation is improved, but the adaptability is worsened because phase information at angles to the measurement plane cannot be captured
Solution Approach 1:
The patent enhances adaptability while maintaining operational simplicity by implementing automatic rotation of the phase grid controlled by the system's coordination unit. The grid rotates to various orientations during scanning, enabling capture of phase information from multiple directions, while the automated control maintains ease of operation without requiring manual intervention for grid repositioning.
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 approach enables the reconstruction of the complete phase shift gradient, allowing for more accurate tomographic imaging and reducing the need for multiple measurements, which is particularly advantageous for living organisms by simplifying the scanning process and improving image resolution.
Implementation Method 1
use is made of the design of a Talbot interferometer
Implementation Method 2
at least one coherent or quasi-coherent X-ray source which generates a beam path
Implementation Method 3
a phase grid with grid lines for generating an interference pattern is positioned in the beam path
Data Source
AI summary
An arrangement and a method are disclosed for projective and/or tomographic phase-contrast imaging using X-ray radiation. In at least one embodiment, one or more phase grids is/are arranged in the beam path such that during a rotation of the at least one X-ray source, the examination object is scanned with different spatial orientations of the grid lines relative to the examination object such that the complete refraction angle, and hence the complete phase shift gradient, can be determined for each X-ray beam from the two scans with differently oriented phase grids in order to be able to show the phase shift of an examination object in terms of projections or in a tomographic image.