Spectral CT kV Ripple Correction Through Frame-Specific Voltage Sensing
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Solution Overview
Problem
Existing spectral CT systems face challenges in accurately correcting energy-dependent X-ray spectra due to voltage fluctuations caused by high-voltage generator capacitive loads, which affect the X-ray tube's performance and result in unpredictable spectral changes across imaging protocols.
Innovation Solution
A spectral correction apparatus that includes an input unit to receive a voltage signal, a processing unit to identify and parameterize voltage fluctuations, and an output unit to correct the effective spectrum of the X-ray source per imaging frame using parameters such as amplitude, harmonic frequencies, and rise/fall times, employing methods like frequency domain filtering, pre-defined calibration tables, simulation models, or machine learning to synchronize spectral corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the capacitive load of the high-voltage cable and X-ray tube is minimized for fast switching performance, then the switching speed is improved, but the voltage fluctuation in the X-ray tube increases
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual tube voltage during operation and using this information to correct the effective energy spectrum. A voltage sensor continuously monitors the HVG output, and the measured voltage values are used to adjust spectral calculations, ensuring accuracy despite voltage fluctuations caused by low capacitive load and fast switching.
Solution Approach 2:
The patent changes the parameter representation from fixed voltage assumptions to dynamic voltage measurement. By measuring actual tube voltage and using it to parameterize the effective energy spectrum for each imaging frame, the system adapts to voltage variations without requiring hardware modification or reducing switching speed.
2Productivity
If fast voltage switching is implemented in the HVG for spectral CT, then the imaging speed is improved, but the voltage fluctuation affects the X-ray spectrum accuracy
Solution Approach 1:
The system uses real-time voltage measurement feedback to correct spectral calculations. The measured tube voltage during fast switching is fed into the spectral correction algorithm, which adjusts the effective energy spectrum for each imaging frame, maintaining measurement precision despite high-speed switching operations.
Solution Approach 2:
The patent performs preliminary voltage measurement and spectral parameterization for each imaging frame before reconstruction. By pre-calculating the effective energy spectrum based on measured voltage values, the system prepares accurate spectral data in advance, ensuring both fast imaging and high spectral accuracy without real-time computational delays.
3Device complexity
If digital spectral correction is performed without hardware modification, then the system complexity is reduced, but the voltage fluctuation correction capability must be achieved through software alone
Solution Approach 1:
The patent replaces hardware-based voltage stabilization mechanisms with a digital correction system. Instead of modifying the HVG hardware to eliminate voltage fluctuations, the system measures the fluctuations and corrects their effects through digital spectral calculation, achieving reliable correction with minimal hardware changes.
Solution Approach 2:
The patent introduces an intermediary measurement system (voltage sensor and measurement circuitry) that bridges the gap between the fluctuating voltage and the spectral correction algorithm. This intermediary captures voltage information and translates it into correction parameters, enabling accurate spectral correction through software processing of measured data.
Data Source
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AI summary
The present invention relates to spectral correction. A spectral correction apparatus is described that is configured to identify a voltage fluctuation in the X-ray tube and to parametrize the high voltage fluctuation to correct the effective X-ray spectrum per individual frame.