Dual-Source CT System Z-Axis Offset for Scatter Reduction
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Solution Overview
Problem
Dual-source CT systems with two-dimensional scattered radiation grids face challenges in correcting transverse scatter, leading to artifacts in images, especially during dual-energy operations, as existing methods are not applicable for devices with such grids.
Innovation Solution
The solution involves offsetting the detector systems and focal points relative to each other in the z-direction to prevent overlap of radiation bundles, allowing the two-dimensional scattered radiation grids to effectively suppress scattered radiation by ensuring the radiation bundles do not intersect, thereby reducing forward scatter and cone beam artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two emitter-detector systems are arranged at different angles on a shared gantry for dual-source CT scanning, then scanning speed and productivity are improved, but transverse scatter is generated that cannot be screened out by two-dimensional scattered radiation grids, resulting in image artifacts
Solution Approach 1:
The patent transitions from two-dimensional scattered radiation grids to three-dimensional scattered radiation grids that extend in the z-direction. This dimensional extension allows the grids to screen transverse scatter that occurs in dual-source CT configurations, resolving the contradiction between improved scanning productivity and the harmful transverse scatter effect.
Solution Approach 2:
The scattered radiation grids are designed with different properties in different spatial dimensions. The grids have specific orientations and densities tailored to screen scatter from each emitter-detector system's specific geometry, allowing localized optimization for each source while maintaining overall system productivity.
2Device complexity
If scattered radiation grids operating in a two-dimensional manner are used, then device complexity is reduced, but they cannot effectively suppress transverse scatter in dual-source configurations, leading to measurement errors
Solution Approach 1:
The patent extends the scattered radiation grids from two-dimensional to three-dimensional structures. This dimensional change enables the grids to effectively suppress transverse scatter in dual-source configurations without requiring overly complex individual grid elements, as the additional z-dimension provides the necessary screening capability.
3Area of stationary object
If radiation bundles from two emitter-detector systems overlap in the examination object, then simultaneous scanning coverage is improved, but scattered radiation from one system interferes with the other detector, creating artifacts
Solution Approach 1:
The three-dimensional scattered radiation grids extend in the z-direction to screen transverse scatter that would otherwise interfere between the two emitter-detector systems. This allows broader scanning coverage while maintaining image quality by preventing cross-system scatter interference.
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 significantly reduces scattered radiation, allowing multi-row detectors to be used fully and minimizing artifacts in CT images, while enabling high-quality dual-energy recordings without the need for additional corrections.
Implementation Method 1
transverse scatter on the object, which, for geometric reasons, can also not be screened out by a scattered radiation grid operating in a two-dimensional manner
Implementation Method 2
having a scattered radiation grid operating in a two-dimensional manner... significant reduction in the scattered radiation amounts
Data Source
AI summary
A method is disclosed for x-ray CT scanning with a dual-source system, in which two radiation bundles are each delimited by diaphragms such that these radiation bundles are free of mutual points of intersection at least in the examination object. An embodiment of the invention also relates to a dual source CT system, including a controller configured to control radiation-delimiting diaphragms, which delimit and align the radiation bundles such that these run free of mutual points of intersection at least in the examination object.