X-ray CT Data Acquisition Holding Time Adjustment
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Solution Overview
Problem
In X-ray CT imaging, especially during helical scans, the existing methods struggle to acquire projection data for reconstructing images at slice positions outside the linear displacement range due to issues with rotating velocity and linear movement velocity, often resulting in incomplete data acquisition.
Innovation Solution
The method involves adjusting a holding time τ at the start and end points of linear movement during X-ray CT data acquisition, allowing for relative rotation without linear movement, which ensures that projection data is acquired across the required view angle range by synchronizing with the velocity and rotation time of the linear movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotating velocity is too slow or the linear movement velocity is too fast, then the scanning efficiency is improved, but the projection data acquisition for slice positions outside the linear movement range becomes incomplete
Solution Approach 1:
The patent applies preliminary action by performing a holding operation at the starting point before linear movement begins. During this holding time, the X-ray tube and detector rotate to acquire projection data for slice positions outside the linear movement range. This preparatory data acquisition ensures that when fast scanning occurs, the necessary projection data for extended slice reconstruction is already collected, resolving the contradiction between scanning speed and data completeness.
2Loss of time
If the linear movement velocity is increased, then the scanning time is reduced, but the view angle range required for image reconstruction cannot be fully acquired
Solution Approach 1:
The holding operation at the starting point serves as preliminary action, where the rotation system accumulates the required view angle range data before rapid linear movement begins. This ensures that even during fast scanning, the projection data covering the necessary view angles for reconstruction is captured during the holding period.
Solution Approach 2:
The patent maintains continuity of useful action by seamlessly transitioning from the holding operation to linear movement. The rotation continues uninterrupted during the holding time, ensuring continuous acquisition of projection data across the required view angle range, which is then combined with data acquired during linear movement for complete image reconstruction.
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
This approach effectively acquires the necessary projection data for image reconstruction at slice positions outside the linear movement range, even when velocities are suboptimal, ensuring complete data collection and accurate image formation.
Implementation Method 1
acquiring projection data by performing a linear movement relative to an imaging object while rotating at least one of an X-ray tube or a multidetector
Data Source
AI summary
The present invention provides a method for positively acquiring projection data for reconstructing a CT image at a slice position outside the linear movement range. When performing “projection data acquisition” with “rotating” and “linearly moving” the X-ray tube and the multidetector, a holding time is provided in which only the “rotation” is performed without “linear movement” at the starting point and the end point of the linear movement. By adjusting the holding time, the projection data in the view angle range required for image reconstruction of a CT at the slice position outside the linear movement range can be positively acquired, when the rotating velocity is slower or when the linear movement velocity is faster.