CT Projection Correction for X-Ray Detector Ring Artifacts
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Solution Overview
Problem
X-ray diagnostic apparatuses face issues with ring artifacts in three-dimensional volume images due to changes in X-ray detector sensitivity when continuously irradiated, leading to inaccurate reconstructions.
Innovation Solution
The apparatus performs reconstruction filter processing to emphasize sensitivity difference areas, generates correction information, and applies correction processing to the projection data to suppress these artifacts, using methods like averaging and inverse filter processing to adjust signal values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the X-ray detector is continuously irradiated with X-rays to maintain high productivity, then the detection speed and productivity are improved, but the X-ray sensitivity of the detector changes causing ring artifacts that worsen measurement precision
Solution Approach 1:
The system performs preliminary sensitivity correction on projection data before reconstruction. The correction unit detects sensitivity differences in the detector and applies correction coefficients to the projection data in advance, preventing ring artifacts from forming in the final image while maintaining continuous irradiation for high productivity
Solution Approach 2:
The system implements a feedback mechanism where the correction unit continuously monitors detector sensitivity changes during continuous irradiation and dynamically adjusts correction coefficients for projection data, ensuring measurement precision is maintained despite ongoing sensitivity drift
2Measurement precision
If correction processing is applied to projection data to improve image quality, then measurement precision is improved, but the processing time increases which reduces productivity
Solution Approach 1:
The system changes parameters by applying correction coefficients to projection data in the frequency domain or by modifying reconstruction parameters, which reduces the computational complexity compared to traditional correction methods and decreases processing time while maintaining image quality
Solution Approach 2:
The correction unit applies partial correction by focusing only on detecting and correcting sensitivity difference areas in the projection data rather than processing all data uniformly, which reduces overall processing time while still eliminating ring artifacts effectively
Data Source
AI summary
A medical image processing apparatus according to an embodiment includes processing circuitry. The processing circuitry acquires a plurality of projection data based on an output signal from an X-ray detector that rotates around a subject, performs reconstruction filter processing on the plurality of acquired projection data, the reconstruction filter processing being included in reconstruction regarding the plurality of projection data, generates correction information on a sensitivity difference area formed in the plurality of projection data due to differences in sensitivity of the X-ray detector, on the basis of a processing result of the reconstruction filter processing, performs correction processing on the plurality of projection data on the basis of the correction information, and performs reconstruction processing including the reconstruction filter processing on the plurality of projection data subjected to the correction processing.