Grating Movement During X-ray Exposure for Phase Contrast Imaging
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Solution Overview
Problem
Conventional X-ray imaging systems face challenges in achieving high contrast between tissue types, requiring high X-ray doses or contrast agents, and struggle with vibration-induced blurring in grating-based phase-contrast and dark-field imaging, which limits acquisition speed and introduces repositioning time gaps.
Innovation Solution
An X-ray imaging system with an interferometric arrangement where gratings are intentionally moved during image acquisition, using short exposure times to prevent fringe pattern washing out and allowing continuous data acquisition, while also tolerating vibrations to reduce acquisition time and patient dosage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gratings are moved in small steps to acquire stepping curves for phase-contrast and dark-field imaging, then image quality and contrast are improved, but acquisition time increases and repositioning time gaps are introduced
Solution Approach 1:
The patent implements continuous grating movement during X-ray exposure without stopping for repositioning. The grating moves at a constant velocity through the entire acquisition range, eliminating idle repositioning time gaps between measurements while maintaining the required stepping curve data collection for phase-contrast and dark-field imaging.
Solution Approach 2:
The system transitions from static step-by-step grating positioning to dynamic continuous movement. The grating moves continuously during exposure, and the detector captures data at multiple positions along the movement trajectory, converting a discrete stepping process into a continuous dynamic measurement process.
2Measurement precision
If gratings are kept stationary during exposure to avoid fringe pattern blurring, then measurement precision is maintained, but acquisition speed decreases due to repositioning time gaps
Solution Approach 1:
The system accepts and compensates for grating movement during exposure rather than preventing it. By moving the grating at a controlled velocity and capturing detector data continuously across multiple positions during the exposure, the system maintains fringe pattern clarity while eliminating repositioning time gaps.
Solution Approach 2:
The useful action of data acquisition continues uninterrupted during grating movement. The detector collects stepping curve data at multiple positions simultaneously during a single continuous exposure, eliminating the need to stop and reposition the grating between measurements.
3Measurement precision
If long exposure times are used to reduce vibrations, then measurement precision is improved, but the system becomes more sensitive to grating movement and vibrations during exposure
Solution Approach 1:
The system uses short exposure times combined with continuous grating movement, replacing the conventional approach of long stationary exposures. This dynamic approach reduces sensitivity to vibrations while maintaining measurement precision through continuous data collection across multiple positions.
Solution Approach 2:
Data acquisition continues uninterrupted during grating movement with short exposure times. The system collects complete stepping curve data through continuous movement rather than through multiple long stationary exposures, reducing vibration sensitivity while maintaining signal stability.
4Reliability
If multiple separate exposures are taken for stepping curve acquisition, then complete phase-contrast and dark-field data are obtained, but repositioning time gaps are introduced between measurements
Solution Approach 1:
The system acquires complete stepping curve data through a single continuous grating movement with continuous detector data collection. The grating moves uninterrupted through the full measurement range, capturing all required phase-contrast and dark-field information without stopping for repositioning between exposures.
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 faster and more efficient acquisition of dark-field, phase contrast, and attenuation image data with reduced X-ray exposure, while maintaining image quality and allowing for continuous data collection, even in the presence of vibrations.
Implementation Method 1
Grating-based phase-contrast (gbPC) X-ray imaging
Implementation Method 2
a Moiré-pattern can be measured with the detector
Implementation Method 3
an image obtained from the dark-field signal
Implementation Method 4
transmission or attenuation (conventional X-ray image)
Data Source
AI summary
The present invention relates to a system (10) for X-ray dark-field, phase contrast and attenuation image acquisition. The system comprises an X-ray source (20), an interferometer arrangement (30), an X-ray detector (40), a control unit (50), and an output unit (60). An axis is defined extending from a centre of the X-ray source to a centre of the X-ray detector. An examination region is located between the X-ray source and the X-ray detector. The axis extends through the examination region, and the examination region is configured to enable location of an object to be examined. The interferometer arrangement is located between the X-ray source and the X-ray detector. The interferometer arrangement comprises a first grating (32) and a second grating (34). For a first mode of operation: The control unit is configured to control at least one lateral movement transducer (70) to move the first grating or move the second grating in a lateral position direction perpendicular to the axis. The control unit is configured to control the X-ray detector to acquire image data whilst the first grating and/or second grating is moving. During an exposure time of the X-ray detector the first grating and/or second grating has moved a distance less than a period of the first grating and/or second grating. The control unit is configured to control movement of the first grating and/or second grating such that the image data is acquired whilst the first grating and/or second grating is moving. For the first mode of operation the output unit is configured to output one or more of: dark-field image data, phase contrast image data, and attenuation image data.