Anti-Scatter Grid Rotational Offset Correction in CT Detectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CT systems lack a means to accurately measure the misalignment of anti-scatter grids (ASGs) and X-ray source position offset, which affects image quality and reconstruction accuracy.
Innovation Solution
A method and apparatus for determining and adjusting the rotational offset of the ASG using count data from an air scan, employing a lookup table and potentially a neural network to calculate and correct the misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an anti-scatter grid is placed in front of the detector to minimize scattered X-rays, then image quality is improved, but the grid may become misaligned causing degradation of the resulting patient image
Solution Approach 1:
The system performs air scans to measure the actual positions of ASG septa relative to detector channels, calculates offset values, and uses this feedback information to correct for misalignment during image reconstruction, thereby maintaining image quality despite potential grid misalignment
Solution Approach 2:
The system dynamically adjusts reconstruction parameters based on measured ASG offset values, modifying the reconstruction algorithm to compensate for grid misalignment and maintain optimal image quality
2Measurement precision
If the ASG is precisely aligned with the detector to ensure accurate measurements, then measurement precision is improved, but the complexity of the system increases due to the need for alignment measurement and adjustment mechanisms
Solution Approach 1:
The system uses the detector itself to measure ASG positions by analyzing air scan data, eliminating the need for separate alignment measurement devices. The ASG alignment is self-diagnosed using the existing detector and scan mechanisms
Solution Approach 2:
Air scans serve as an intermediary measurement method, using the absence of patient tissue to isolate and measure ASG positions relative to detector channels without requiring direct physical alignment tools
3Measurement precision
If the pixel size is reduced to improve energy resolving performance in photon counting CT, then energy resolution is improved, but the ASG design must maintain the same pitch/spacing to achieve high dose efficiency
Solution Approach 1:
The system measures and compensates for ASG-detector offset values that arise from the mismatch between ASG pitch and reduced detector pixel pitch, allowing the use of smaller pixels for better energy resolution while maintaining compatibility with standard ASG designs
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
Improves image quality by accurately aligning the ASG with the detector, reducing scatter artifacts and enhancing reconstruction accuracy.
Implementation Method 1
scattered X-rays from oblique angles can be absorbed by the ASG, while straight line path X-rays can freely reach the detector
Implementation Method 2
The attenuation of the radiation that has passed through the body is measured by processing electrical signals received from the detector
Data Source
AI summary
A method of imaging includes analyzing a first image to detect objects in the first image and corresponding features of the objects; based on a detection result of a first object having a corresponding first object feature in the first image, selecting an action corresponding to the first object and the first object feature from a database; determining an updated set of scan parameters based on the selected action; and adjusting at least one of the table, the X-ray source, the X-ray detector, and the arm based on the updated set of scan parameters.