Multi-Spectral X-Ray Tomography With Limited-Angle Low-Dose Scans
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Solution Overview
Problem
Existing dual-energy X-ray tomography methods, such as dual-energy CT imaging, require multiple full-rotation scans, doubling the imaging time and dose, and involve significant hardware additions, which increase cost and complexity, limiting their widespread adoption, especially in non-diagnostic CT systems like C-arm CT.
Innovation Solution
An optimization-based image reconstruction methodology for multi-spectral X-ray tomography (MSXT) that allows for image reconstruction using non-standard scan configurations without hardware modifications, enabling fast, low-dose dual-energy imaging on existing CT systems by controlling the X-ray source and detector movements to collect limited data sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional x-ray sources are used, then sufficient x-ray flux is achieved, but radiation dose to the subject is too high and imaging speed is limited
Solution Approach 1:
The patent changes the energy parameters of x-rays by using multiple spectral windows (energy ranges) to image the same subject. Different materials absorb x-rays differently at different energies, allowing extraction of material-specific information. This enables low-dose imaging because the system can distinguish materials based on their spectral signatures rather than requiring high flux for contrast
Solution Approach 2:
The patent segments the x-ray spectrum into multiple discrete energy windows (e.g., low energy, mid energy, high energy bands). By acquiring images at multiple energy levels and processing them separately, the system can reconstruct material composition information. This segmentation allows the use of lower total flux since each energy band contributes specific material discrimination information
2Device complexity
If conventional single-energy x-ray imaging is used, then simple imaging is achieved, but material differentiation capability is insufficient
Solution Approach 1:
The system varies the energy parameter of x-rays across multiple spectral windows to enhance material differentiation. By measuring attenuation at different energies and analyzing the spectral characteristics, the system can distinguish between materials with similar physical properties (e.g., different plastics, explosives, drugs) that would be indistinguishable in single-energy imaging
Solution Approach 2:
The patent introduces spectral decomposition algorithms as an intermediary processing step between image acquisition and material identification. The system decomposes the measured spectral data into basis material components, enabling quantitative material differentiation. This computational intermediary transforms simple transmission measurements into detailed material composition information
3Measurement precision
If multiple spectral windows are acquired sequentially, then material-specific information is extracted, but imaging time increases
Solution Approach 1:
The patent employs periodic modulation of the x-ray source energy output, cycling through multiple spectral windows in a rapid sequence. By synchronizing the detector acquisition with this periodic energy modulation, the system captures multiple energy bands efficiently. The periodic nature allows for temporal separation of energy bands while maintaining overall imaging speed
Solution Approach 2:
The system performs preliminary calibration and spectral decomposition setup before the actual imaging sequence. Energy window definitions, basis material selections, and reconstruction parameters are pre-configured based on expected target materials. This preliminary action optimizes the subsequent rapid multi-energy acquisition, reducing the time penalty of spectral imaging
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 fast, low-dose dual-energy imaging on conventional CT systems, reducing hardware costs and complexity, and enhancing scanning flexibility, while maintaining image quality and accuracy.
Implementation Method 1
different materials absorb x-rays differently at different energies, allowing extraction of material-specific information
Implementation Method 2
acquire images of the subject at multiple discrete energy levels or spectral windows
Data Source
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AI summary
A multi-spectral tomography imaging system includes one or more source devices configured to direct beams of radiation in multiple spectra to a region of interest (ROI), and one or more detectors configured to receive the beams of radiation. The system includes a processor configured to cause movement in at least one of the components such that a first beam of radiation with a first spectrum is directed to the ROI for less than 360 degrees of movement of the ROI. The processor is also configured to process data detected by the one or more detectors, where the data results at least in part from the first beam of radiation with the first spectrum that is directed to the ROI for less than the 360 degrees of movement of the ROI. The processor is further configured to generate an image of the ROI based on the processed data.