Dual-Energy CT Material Identification via Undersampling
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Solution Overview
Problem
Dual-energy CT imaging systems face challenges of high cost, increased radiation dose, and slow scanning speed due to the need for multiple detectors and additional scanning rounds, limiting their widespread application in fields like security inspection and medical treatment.
Innovation Solution
A dual-energy material identification method and system that employs under-sampling, using a single tier of detectors and reduced scanning angles at a second energy level, combined with dual-energy preprocessing and decomposition reconstruction to compute atomic numbers and identify materials, thereby reducing costs and radiation dose while enhancing scanning speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pseudo dual-energy system with double-tiered detectors is used, then dual-energy imaging capability is achieved, but system cost and device complexity increase significantly
Solution Approach 1:
The patent merges the dual-energy imaging capability into a single detector tier by implementing energy discrimination at the detector level. The single-tier detector simultaneously captures both low-energy and high-energy information through energy-resolving photodetectors, eliminating the need for separate detector tiers while maintaining dual-energy functionality.
Solution Approach 2:
The patent replaces the physical separation of detector tiers with an electronic/photonic energy discrimination system. Instead of using mechanical or physical layering of detectors, the system uses photodetector elements that electronically distinguish between different energy levels of incoming photons, substituting a complex mechanical detector architecture with a more integrated photonic detection approach.
2Measurement precision
If a real dual-energy system performs circular scanning with ray sources of different energy levels, then accurate material identification is achieved, but radiation dose and scanning time double
Solution Approach 1:
The patent employs periodic modulation of the X-ray source energy levels during a single scanning rotation. The source alternates between low-energy and high-energy emission in a periodic manner, allowing the single detector tier to capture both energy levels' projection data during one complete scan, thereby halving the total radiation dose compared to two separate scans.
Solution Approach 2:
The system performs preliminary energy discrimination at the detector level during data acquisition. By pre-separating the detected photons into energy bands at the point of detection, the system prepares the data in a form that enables accurate material identification without requiring subsequent complex post-processing or additional scanning rounds.
3Productivity
If dual-energy CT imaging uses two tiers of detectors for simultaneous collection, then dual-energy data is obtained, but system cost and complexity increase
Solution Approach 1:
The patent makes the single detector tier universal by designing it to perform multiple functions: detecting both low-energy and high-energy photons, discriminating between energy levels, and generating separate projection data streams for both energy bands. This multi-functional detector design eliminates the need for specialized detector tiers while maintaining full dual-energy data acquisition capability.
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 fast, low-dose dual-energy material identification, making the technology more applicable and cost-effective for security inspection and medical treatment by reducing the need for multiple detectors and scanning rounds.
Implementation Method 1
acquiring a photoelectric coefficient integral value and a Compton coefficient integral value from the dual-energy under-sampled data
Implementation Method 2
acquiring a photoelectric coefficient integral value and a Compton coefficient integral value from the dual-energy under-sampled data
Data Source
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AI summary
A dual-energy material identification method and system with under-sampling is disclosed. A CT image of the object is obtained by using the CT image reconstruction method, while the dual-energy projections are under-sampled to obtain a few samples. Photoelectric coefficient integral and Compton coefficient integral are computed from these dual-energy projection data. The CT image is segmented into regions with image processing technique, and the regions are labeled. The length by which a few dual-energy rays crosses each labeled region is computed, and an equation system is established with dual-energy preprocessing dual-effect decomposition reconstruction method to compute Photoelectric coefficient and Compton coefficient, and then atomic number and electron density of material in each region are computed. The material of the object can be identified with the atomic number.