X-ray Phase Contrast Imaging Stochastic Scanning
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Solution Overview
Problem
Conventional X-ray systems face significant challenges in maintaining mechanical stability and image quality when upgrading to Talbot-Lau apparatuses, particularly due to displacements of the X-ray tube and detector, which can result in dramatic deterioration of image information, especially in C-arm devices where vibrational motions are common.
Innovation Solution
The X-ray image detector and phase/grating components are fixedly connected, allowing for relative lateral displacement during image recording, subdividing the process into partial images to maintain image information and eliminate the need for active phase stepping, thereby achieving stochastic phase scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the X-ray tube and detector are mounted on a C-arm allowing vibrational motions, then the system provides flexibility for medical imaging procedures, but lateral mechanical displacements of approx. a hundred micrometers occur which dramatically deteriorate image information in Talbot-Lau apparatus
Solution Approach 1:
The patent applies preliminary action by determining the position of the analyzer grating relative to the phase grating before the actual image recording takes place. A reference measurement is performed first to establish the initial position relationship, which then serves as a baseline for subsequent displacement corrections during the imaging process. This preliminary positioning ensures that even if mechanical displacements occur during imaging, the system can accurately compensate and maintain image quality.
2Measurement precision
If active phase stepping with piezo-stepper is used to scan the interference pattern, then precise image information can be obtained, but the system requires high mechanical stability and active control mechanisms that increase complexity
Solution Approach 1:
The patent replaces the traditional mechanical phase-stepping mechanism (piezo-stepper) with a computational approach. Instead of physically moving the analyzer grating in precise steps, the system captures a single image with the grating in one position and then uses computer algorithms to synthesize the phase-stepping information. This substitution eliminates the need for precision mechanical actuators and their associated control systems, significantly reducing device complexity while maintaining measurement precision.
3Loss of information
If the analyzer grating is laterally displaced in fractions of the grating period to scan the intensity distribution, then phase stepping is achieved, but the displacement distances are in the range of micrometers requiring considerable mechanical stability
Solution Approach 1:
The patent creates a computational copy of the phase-stepping process rather than performing physical displacements. By capturing the intensity distribution at a single grating position and using algorithmic processing to generate the equivalent information that would be obtained through physical phase stepping, the system preserves all necessary image information without requiring micrometer-level mechanical stability. The computational model replicates what would otherwise require precise mechanical movement.
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 ensures that image information is preserved and image quality is maintained even with displacements, as the total exposure time is broken down into partial exposure times, allowing for precise determination of component positions and intensity patterns, effectively addressing the mechanical stability and image deterioration issues.
Implementation Method 1
at least one X-ray emitter (3) for generating a quasi-coherent X-ray beam
Implementation Method 2
a diffraction or phase grating (19) which is arranged between the object and the X-ray image detector
Implementation Method 3
an analyzer grating (21) associated with the phase grating for generating an intensity pattern or interference pattern
Data Source
AI summary
A method, for examining an object using an X-ray recording system, includes during an X-ray image recording, moving components relative to one another with the lateral displacement by displacement distances. The method includes generating the X-ray image recording during the displacement from n partial images, so that the total exposure time of the X-ray image recording is made up from a sum of partial exposure times. In each of the partial images, the intensity is determined in each pixel. The position of the second component relative to the first component is determined for each recording of the partial images. Finally, the image information is determined from the partial images and the displacements.