Cone Beam Artifact Reduction in X-ray CT Reconstruction
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Solution Overview
Problem
Cone beam artifacts significantly affect the quality of volume data in X-ray computed tomography imaging due to increased cone angles, particularly in circular and helical scanning techniques, leading to incomplete data acquisition, workflow complications, and increased subject dose.
Innovation Solution
An X-ray computed tomography method that reduces cone beam artifacts through a processing workflow involving low-pass and high-pass filtering, threshold processing, and subtraction methods applied to projection and volume data, without requiring additional scanning or limiting helical pitch, thereby generating volume data with minimized artifact components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cone beam reconstruction is performed with increased cone angle, then volume data can be acquired faster, but cone beam artifacts noticeably appear in the volume data
Solution Approach 1:
The patent extracts and removes cone beam artifact components from the projection data through a dedicated artifact correction process. The system identifies artifact components in the projection data and subtracts them before performing reconstruction, thereby eliminating the source of image degradation while preserving the fast scanning capability
Solution Approach 2:
The patent applies a counteracting approach by introducing correction data that opposes the cone beam artifacts. The artifact correction process generates compensating information that counterbalances the artifact effects, allowing reconstruction to proceed with improved accuracy despite the large cone angle
2Reliability
If Line + Circle scanning is used to acquire enough projection data, then complete solution can be obtained, but additional scanning complicates workflow and increases subject dose
Solution Approach 1:
The patent performs artifact correction on the projection data before reconstruction, preparing the data in advance for complete and accurate reconstruction. This preliminary processing ensures that the projection data is sufficient and corrected, eliminating the need for additional scanning while maintaining workflow simplicity
3Reliability
If Katsevich reconstruction method is used for helical scanning, then complete solution can be obtained, but the method is limited in terms of helical pitch
Solution Approach 1:
The patent changes the approach from pitch-constrained reconstruction to a universal artifact correction method that works across all helical pitch values. By correcting artifacts in the projection data domain before reconstruction, the system achieves complete solutions for any helical pitch without being limited by the constraints of previous methods
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
The method effectively reduces cone beam artifacts in X-ray CT imaging, improving image quality by suppressing artifact components in both the Z and X-Y directions, without the need for additional scanning or complex calculations, thus enhancing the accuracy and efficiency of the imaging process.
Implementation Method 1
an X-ray tube configured to generate cone beam X-rays
Implementation Method 2
an X-ray detector configured to detect the cone beam X-rays generated by the X-ray tube
Data Source
Figure 1
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AI summary
An X-ray computed tomography apparatus scans a subject to be examined with cone beam X-rays, and generates reference volume data on the basis of projection data (SA1). This apparatus extracts a cone beam artifact component contained in the reference volume data on the basis of the typical shape and direction of the cone beam artifact component (SA2, SA3, SA4, SA5, and SA6). This apparatus generates resultant volume data with the reduced cone beam artifact by subtracting the cone beam artifact component from the reference volume data (SA7).