Spatially Modulated Filter Grating for Spectral Separation in CT
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Solution Overview
Problem
Current X-ray imaging systems face challenges in reducing radiation dose and scattered X-ray radiation, which leads to image artifacts and increased patient exposure, while also struggling to achieve strong spectral separation for material differentiation in CT scans.
Innovation Solution
The system employs a collimator and a spatially modulated filter with alternating spectral filtration, using multiple X-ray sources and a filter grating to ensure each pixel receives distinct spectra, minimizing overlap and allowing for precise spectral and spatial separation of X-ray beams, thereby reducing dose and enhancing material differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatially modulated filter with alternating spectral filtration is used, then spectral separation is improved, but device complexity increases
Solution Approach 1:
The filter is segmented into multiple zones with alternating spectral filtration properties, where each zone applies different energy attenuation characteristics to adjacent X-ray beams. This segmentation enables spectral separation across different detector pixels while maintaining a relatively simple overall filter structure that can be integrated into existing CT systems.
Solution Approach 2:
Different regions of the filter are assigned different spectral filtration properties (e.g., different materials or thicknesses) to create local variations in X-ray energy attenuation. This local quality approach allows each pixel to receive a distinct spectrum tailored for specific material differentiation, resolving the contradiction between spectral precision and device complexity.
2Object-affected harmful factors
If total X-ray exposure is limited to minimum, then patient radiation dose is reduced, but image quality deteriorates
Solution Approach 1:
The system changes the spectral parameters of X-rays by using filters with different attenuation characteristics across spatial zones. This allows the same total exposure to produce more informative images by varying the energy spectrum, enabling better material differentiation without increasing radiation dose.
Solution Approach 2:
The spatially modulated filter acts as an intermediary that modifies the X-ray spectrum before it reaches the patient and detector. By strategically placing filters with different properties, the system optimizes the balance between radiation dose and image quality, reducing harmful effects while maintaining diagnostic reliability.
3Illumination intensity
If scattered X-ray radiation is present, then detector signal intensity increases, but image artifacts increase
Solution Approach 1:
The system extracts and separates scattered radiation from the primary beam by using the spatially modulated filter to create distinctive spectral signatures. This allows the detection and correction of scattered radiation contributions, removing the harmful artifact-generating component while preserving the useful signal intensity.
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 reduces patient dose by up to 20% and improves spectral separation, enabling better material differentiation and reduced image artifacts by ensuring each pixel receives a unique spectrum, enhancing the accuracy of CT scans.
Implementation Method 1
a filter providing different spectral filtration within an X-ray system in order to produce a spectrally modulated beam such that neighboring pixels of the X-ray detector receive different spectra
Data Source
Figure 1
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Figure 3a~3c
AI summary
An X-ray imaging system for generating X-ray projections of an object, the X-ray imaging system including an X-ray device having a single X-ray source (110) for forming a plurality of X-ray beams (104), a filter (120) positioned within the plurality of X-ray beams, an object space where the object to be imaged is accommodated, and an X-ray detector (150) including an array of a plurality of pixels (151... 155). The X-ray device, the filter, and the plurality of pixels are configured such that at least one pixel is exposed to the plurality of X-ray beams. X-ray radiation received by a particular pixel undergoes a same spectral filtration by the filter. Pixels receiving the X-ray radiation undergoing the same spectral filtration are summarized to a pixel subset.