Cone Beam CT Reconstruction Using Dual-Angle Correction
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Solution Overview
Problem
Cone beam artifacts are more noticeable in half reconstruction methods of cone beam CT, leading to a deterioration in image quality, as they lack complete Radon data and time resolution is sacrificed for image quality.
Innovation Solution
An X-ray computed tomography apparatus that generates first volume data from a 180°+fan angle projection dataset and second volume data from a 360° dataset, using correction data to reduce cone beam artifacts by subtracting and smoothing the difference between the two, and adding the omitted component image to the half reconstruction data to achieve image quality similar to full reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If half reconstruction method is used in cone beam CT, then time resolution is improved (shorter acquisition time), but image quality deteriorates due to noticeable cone beam artifacts
Solution Approach 1:
The invention segments the reconstruction process into two parts: first generating half-reconstruction volume data from 180°+fan angle projection data for fast time resolution, then generating correction data from the difference between this and full-reconstruction volume data to compensate for the missing Radon data. This segmentation allows the system to benefit from both fast acquisition and high image quality.
Solution Approach 2:
The invention changes the parameter of projection data coverage angle. By acquiring projection data over a wider angle range (180°+fan angle instead of exactly 180°), the system obtains more complete Radon data while still maintaining the time resolution advantages of half reconstruction, thereby reducing cone beam artifacts.
2Manufacturing precision
If conventional weighting techniques are applied to half reconstruction data, then artifacts are partially managed, but the fundamental problem of omitted Radon data remains unresolved
Solution Approach 1:
The invention uses feedback by generating correction data based on the difference between half-reconstruction and full-reconstruction volume data. This correction data is then added back to the half-reconstruction data to compensate for the omitted Radon data, creating a feedback loop that improves image quality without sacrificing time resolution.
Data Source
AI summary
An X-ray computed tomography apparatus includes a gantry, a reconstruction processing unit which generates first volume data on the basis of a projection data set which covers an angle range of 180°+a fan angle and also generates second volume data on the basis of a projection data set which covers an angle range of 360°, a correction data generating unit which generates correction data for reducing a cone beam artifact on the basis of a difference between the first volume data and the second volume data, and a correction unit which corrects the first volume data on the basis of the correction data.