Photon-Counting CT Dynamic Energy Bin Adjustment
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Solution Overview
Problem
X-ray CT devices with photon-counting mode face challenges in reducing statistical noise on the low-energy side, leading to degraded image quality due to significant attenuation of low-energy X-rays, especially in areas with bones or metal, requiring frequent adjustments in energy bins and scanning conditions which increase X-ray exposure and time.
Innovation Solution
A photon-counting CT device that dynamically adjusts the energy bands based on pre-measured X-ray attenuation distributions, expanding energy widths in bins with high attenuation to increase photon counts and reduce noise, allowing for real-time image reconstruction with reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PCCT device uses fixed energy bins for photon counting, then the device complexity is reduced and operation is simpler, but statistical noise on the low-energy side increases significantly due to X-ray attenuation in areas with bones or metal
Solution Approach 1:
The patent implements dynamic energy bin configuration where the energy bin ranges are automatically adjusted based on the measured X-ray attenuation distribution. Instead of fixed energy bins, the system dynamically determines optimal energy bin boundaries for each imaging scenario, allowing the low-energy bin to expand into regions with fewer attenuated photons while the high-energy bin contracts. This dynamic adaptation resolves the contradiction by maintaining image quality through optimized energy binning without requiring manual operator intervention.
Solution Approach 2:
The system changes the parameter of energy bin boundaries based on the measured attenuation distribution. By calculating the actual photon counts in different energy regions and adjusting the energy bin parameters accordingly, the system optimizes the distribution of photons across bins to minimize statistical noise. This parameter change approach allows the device to adapt to different imaging conditions (such as presence of bones or metal) without increasing operational complexity.
2Reliability
If the energy bins are adjusted manually to reduce noise in low-energy regions, then image quality improves, but the processing time increases and X-ray exposure must be increased
Solution Approach 1:
The patent performs preliminary measurement of the X-ray attenuation distribution before final image reconstruction. This preliminary action provides the necessary information to automatically configure optimal energy bins without requiring manual adjustment during the imaging process. The system uses this preliminary data to pre-determine the energy bin boundaries that will minimize statistical noise, thereby reducing processing time while maintaining image quality.
Solution Approach 2:
The system implements a feedback mechanism where the measured attenuation distribution and photon counts are used to automatically adjust energy bin configuration. The feedback loop continuously optimizes the energy bin settings based on actual imaging conditions, eliminating the need for manual intervention and reducing processing time. The feedback-driven automatic adjustment ensures optimal image quality without increasing X-ray exposure or processing time.
3Loss of information
If the PCCT device counts photons in multiple fixed energy bins, then spectral information is preserved for element estimation, but the number of detected photons in low-energy bins becomes extremely small causing noise
Solution Approach 1:
The system dynamically changes the energy bin parameters based on the measured attenuation distribution and photon count distribution. By adjusting the energy bin boundaries, the system optimizes the photon distribution across bins to ensure sufficient photon counts in each bin for reliable statistical measurement. This parameter adjustment maintains spectral information while improving the signal-to-noise ratio in low-energy regions where attenuation is severe.
Solution Approach 2:
The patent applies different energy bin configurations to different energy regions based on local conditions. The low-energy bins are expanded to capture more photons in regions where attenuation is high, while high-energy bins are configured to preserve spectral information. This local optimization approach ensures that each energy bin has sufficient photon counts for reliable measurement while maintaining the overall spectral distribution needed for element estimation.
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 rapid display of images with reduced noise by optimizing energy bands for each section, minimizing X-ray exposure and processing time while maintaining image quality.
Implementation Method 1
a photon counting type detector counts photons of X-rays (X-ray photons) that have passed through a subject
Implementation Method 2
An X-ray source and an X-ray detector are positioned to face each other with a subject therebetween
Implementation Method 3
X-rays are likely to attenuate significantly, when passing through inside of the subject... X-rays on the low energy side are likely to attenuate more drastically within the subject, relative to the X-rays on the high energy side
Data Source
AI summary
X-ray photons are counted as to each of energy bands (bins) to which optimum energy ranges are provided, and an image with reduced noise is displayed in a short time. An energy range of at least one of multiple energy bands in an X-ray detector is adjusted, on the basis of a distribution of degrees of X-ray attenuation at respective energy levels, the distribution of degrees of X-ray attenuation being measured in advance with respect to a predetermined direction of a subject. By using the X-ray detector with the energy bands after the adjustment, photon-counting CT imaging is performed.