Pixelated K-edge Coded Aperture for Spectral CT Imaging
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Solution Overview
Problem
Conventional spectral computed tomography (SCT) methods face challenges such as high costs and low signal-to-noise ratios due to the use of photon counting detectors, and are time-intensive due to the need for multiple scans with standard integrating detectors.
Innovation Solution
A pixelated K-edge coded aperture structure is used to encode and filter X-ray beams, allowing for the generation of spectral computed tomography data by transmitting X-ray beams through a structure with multiple openings associated with K-edge filters, which reduces the need for multiple scans and improves energy resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photon counting detectors are used to achieve higher energy resolution, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
A coded aperture mask with K-edge filters is introduced as an intermediary component between the X-ray source and the detector. This mask modulates the X-ray spectrum before detection, enabling spectral information to be encoded in the spatial domain. The detector then captures this encoded information, which can be decoded computationally to achieve spectral imaging with a simpler, lower-cost detector architecture.
Solution Approach 2:
The patent replaces the need for complex photon-counting detector electronics with a simpler integrating detector combined with a physical coded aperture mask. The spectral discrimination function, traditionally performed by complex detector electronics, is transferred to a passive optical element (the coded aperture mask), thereby reducing detector complexity and cost while maintaining spectral resolution capability.
2Device complexity
If standard integrating detectors are used for spectral CT imaging, then device complexity is reduced, but productivity decreases due to the need for multiple scans
Solution Approach 1:
The patent combines spectral filtering and spatial encoding into a single coded aperture mask structure. Multiple K-edge filters are arranged in a coded pattern within the same mask, allowing simultaneous encoding of multiple spectral channels in a single X-ray exposure. This merging of functions enables spectral imaging to be achieved in a single scan rather than requiring multiple sequential scans.
Solution Approach 2:
The patent transforms the spectral dimension into the spatial dimension through coded aperture encoding. Instead of measuring spectral information sequentially at different energy levels, the spectrum is encoded spatially across multiple detector pixels, each receiving a unique coded combination of spectral components. This dimensional transformation allows parallel acquisition of spectral information, dramatically improving scanning speed.
3Measurement precision
If multiple scans are performed to achieve spectral imaging, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The coded aperture mask is pre-configured with specific K-edge filter patterns that encode spectral information into the spatial distribution of X-rays. This preliminary encoding of spectral data in the mask structure allows all necessary spectral measurements to be captured simultaneously in a single scan, eliminating the need for multiple sequential scans and the associated time delays.
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 spectral CT images with reduced radiation dose and scanning time, while maintaining image quality, by creating structured X-ray bundles that interrogate specific target pixels and using quasi-monochromatic X-ray spectra to overcome the limitations of traditional detectors.
Implementation Method 1
The plurality of openings are associated with at least one K-edge filter, such that the difference of the spectra of the plurality of X-ray beams transmitted through the plurality of openings has an energy band corresponding to a difference between K-edge values of a corresponding balanced pair of K-edge filters
Data Source
AI summary
Aspects of the invention are directed to systems and methods for generating spectral computed tomography data for spectral X-ray image reconstruction using of pixelated k-edge apertures. A method is provided for generating a spectral computed tomography. The method includes the steps of generating a plurality of X-ray beams; encoding the plurality of X-ray beams by transmitting the plurality of beams through a pixelated K-edge coded aperture structure; detecting the encoded plurality of X-ray beams; and reconstructing a spectral CT image from the encoded plurality of X-ray beams.