CT Wedge Filter Scatter Correction Using Air-Scan Fitting
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Solution Overview
Problem
Existing methods for correcting scatter signals caused by wedge filters in CT equipment are scene-dependent and require calibration for each scenario, leading to inaccuracies in scatter signal removal.
Innovation Solution
A method involving air scans and object scans using narrow and wide collimators to calculate relative scatter signal intensities, followed by a fitting formula to estimate and correct scatter signals in actual scans, reducing the need for scene-specific calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an anti-scatter grid or computing model-based correction algorithm is used to remove scatter signals caused by the wedge filter, then the scatter signal removal effectiveness is improved, but the scene dependence increases and calibration is required for each scene
Solution Approach 1:
The patent performs air scans to measure wedge filter scatter signals before actual object scans. By pre-characterizing the scatter signal intensity and distribution from the wedge filter alone (without objects), the system creates a reference dataset that can be applied to correct subsequent scans. This preliminary measurement eliminates the need for scene-specific calibration while maintaining accurate scatter correction across different scanning scenarios.
Solution Approach 2:
The patent creates a computational model that copies the scatter signal characteristics measured during air scans. By storing the scatter signal intensity and spatial distribution patterns from wedge-only scans, the system can replicate and subtract these scattered signal patterns from actual object scans, achieving consistent correction without requiring recalibration for each new scene or object type.
2Ease of manufacture
If air calibration is performed to remove partial scatter signals caused by the wedge filter, then the calibration process is simplified, but the scatter signal removal completeness deteriorates
Solution Approach 1:
The patent performs air scans that deliberately over-measure the scatter signal by including not only the wedge filter scatter but also any residual scatter from the scanner environment. By capturing this excessive scatter signal during air scans and then selectively applying only the wedge-related portion during object scan correction, the system achieves both simple calibration (single air scan procedure) and complete scatter removal (accurate wedge scatter characterization).
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 provides accurate scatter signal correction applicable to clinical patients with fewer algorithms, enhancing scan accuracy and reducing residual scatter signal impact.
Implementation Method 1
Because the wedge filter is a relatively strong attenuation object, the wedge filter generates scatter signals outside a scanned object
Implementation Method 2
the wedge filter generates scatter signals outside a scanned object
Data Source
AI summary
A correction method for a scatter signal caused by a wedge filter includes: S10: performing an air scan by using CT equipment, and calculating a relative intensity Wair of a scatter signal caused by a wedge filter in the air scan according to an air scan result, S20: performing an object scan on a plurality of experimental objects by using the CT equipment, and calculating theoretical scatter signal intensities Wtheo of the experimental objects in the object scan in combination with the result of S10, S30: fitting Wtheo of the experimental objects in the object scan and scatter signal intensity estimations Wact of the experimental objects in the object scan, and S40: correcting the scan results according to a difference between a scatter signal intensity estimation Wact of an actual object in the object scan and a theoretical scatter signal intensity Wtheo of the actual object in the object scan.