Structured Scintillator X-ray Detector Fringe Sampling
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Solution Overview
Problem
Existing X-ray detectors for phase contrast and dark-field X-ray imaging require a mechanically movable analyzer grating, which increases complexity and patient radiation dose, and lacks sufficient resolution for direct fringe measurement.
Innovation Solution
An X-ray detector with a structured scintillator layer and optical detector layer comprising sub-pixels that sample and convert X-ray fringe patterns into optical signals, allowing direct detection of fringe phase and visibility without an analyzer grating, using silicon photomultipliers for efficient signal detection and a signal combination arrangement to generate output signals from adjacent sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanically movable analyzer grating is used in conventional X-ray phase contrast imaging, then fringe pattern sampling is achieved, but device complexity and patient radiation dose increase
Solution Approach 1:
The invention extracts and eliminates the mechanically movable analyzer grating from the conventional Talbot-Lau interferometer setup. Instead of using a separate movable grating component, the detector itself performs direct fringe measurement through its pixel array, thereby removing the complex mechanical moving parts while retaining the essential fringe sampling function
Solution Approach 2:
The invention merges the fringe sampling function previously performed by the movable analyzer grating directly into the detector structure. The detector pixels are configured to directly sample the fringe pattern at the detector plane, combining the detection and sampling functions into a single integrated system without requiring separate mechanical components
2Measurement precision
If sub-pixel size is reduced to increase detector resolution for direct fringe measurement, then measurement precision improves, but detector noise increases
Solution Approach 1:
The invention segments each physical detector pixel into multiple virtual sub-pixels through signal processing. Each pixel's output signal is divided and assigned to multiple sub-pixel positions based on the expected fringe pattern phase, enabling high-resolution fringe sampling without requiring physically smaller detector pixels that would increase noise
Solution Approach 2:
The invention creates virtual copies of detector pixel signals to populate sub-pixel positions. The signal from each physical pixel is replicated and distributed to multiple sub-pixel locations according to the fringe phase information, effectively creating high-resolution fringe samples from lower-resolution physical detector elements
3Device complexity
If analyzer grating is removed for direct fringe detection, then device complexity reduces, but signal detection capability must be maintained
Solution Approach 1:
The invention replaces the mechanical analyzer grating system with an electronic signal processing system. Instead of using physical gratings to modulate and sample the fringe pattern, the system uses digital signal processing to extract fringe information directly from the detector pixel signals, substituting mechanical optical elements with computational methods
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 enhances X-ray detector resolution and information output, reduces detector noise, and enables phase contrast and dark-field imaging in multiple directions without moving the detector or patient, improving image accuracy and reducing radiation exposure.
Implementation Method 1
a structured scintillator layer comprising a plurality of slabs arranged to sample the incident fringe pattern and convert it into a plurality of optical slab signals
Implementation Method 2
an optical detector layer in optical communication with the structured scintillator layer comprising a plurality of sub-pixels, wherein each sub-pixel is aligned with a respective slab of the structured scintillator layer to detect a respective optical slab signal
Data Source
Figure 1~2d
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AI summary
In a conventional phase-contrast X-ray imaging system, a source grating G0 generates an array of partially coherent line sources which illuminate an object and thereafter phase grating G1. The periodicity in the phase grating is self-imaged at certain instances further away from the X-ray source and sampled by a mechanically movable third absorptive analyzer grating G2 before the demodulated fringe intensity is detected by a conventional X-5 ray detector. This application proposes to directly demodulate the fringe intensity using a structured scintillator having a plurality of slabs in alignment with sub-pixels of an optical detector layer, in combination with electronic signal read-out approaches. Therefore, a mechanically movable third absorptive analyzer grating G2 can be omitted from a phase-contrast X-ray imaging system.