CT Detector Grids Block X-Ray Crosstalk
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Solution Overview
Problem
CT detectors with fewer modules and more channels per module suffer from X-ray crosstalk due to gaps between scintillators, leading to artifacts in the image, as X-rays can shift to adjacent pixels, causing flare angle discrepancies and performance issues.
Innovation Solution
The implementation of two-dimensional grids with breaking joints, positioned between detector modules and collimator plates, to block X-rays from entering gaps between scintillators and prevent crosstalk, using materials like tungsten or high-density alloys for strong X-ray absorption, with gridline thickness, width, and pitch optimized between 80 micrometers and 3 millimeters, and 10 micrometers and 700 micrometers respectively, and pitch of 0.08 millimeters to 3 millimeters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the number of detector modules is reduced and channels per module are increased, then manufacturing cost is reduced, but X-ray crosstalk occurs due to gaps between scintillators
Solution Approach 1:
A grid structure is introduced as an intermediary component between the scintillator array and the X-ray source. This grid acts as a mediator that selectively blocks X-rays directed toward the gaps between scintillators while allowing X-rays to pass through to the active detection areas, thereby eliminating crosstalk without requiring additional detector modules
Solution Approach 2:
The grid is segmented into multiple sections with breaking joints, allowing it to be divided into manageable parts for manufacturing and assembly. Each segment corresponds to specific detector modules, enabling precise placement of grid sections to block gaps between scintillators while maintaining alignment with the detector array geometry
2Device complexity
If detector modules are arranged in a polyline shape with more channels per module, then the number of detector modules is reduced, but pixel dimensions no longer correspond to equal flare angles
Solution Approach 1:
The grid structure is designed with locally optimized characteristics, where different sections of the grid have different geometries and blocking densities tailored to the specific requirements of each detector module section. This allows each local region to maintain proper flare angle correspondence while accommodating the overall polyline arrangement of reduced detector modules
3Reliability
If X-rays enter the gaps between adjacent scintillators, then crosstalk is produced causing image artifacts, but blocking the gaps requires additional structural elements
Solution Approach 1:
The grid structure is integrated with the existing detector module assembly, combining the crosstalk blocking function with the structural framework already present in the detector system. The grid is positioned to utilize existing mounting structures and alignment features, merging the new blocking function with the existing detector architecture rather than adding completely separate structural elements
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
Prevents X-rays from entering gaps between adjacent pixels, eliminating crosstalk and enhancing image quality by ensuring equal flare angles, facilitating efficient manufacturing with continuous cutting processes.
Implementation Method 1
using materials like tungsten or high-density alloys for strong X-ray absorption
Data Source
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AI summary
The present invention relates to a CT detector 103, comprising: a detector module 301 that includes multiple scintillators 303 having gaps 306 therebetween and for constituting two-dimensional discrete pixels; a collimator plate 302 located above one side of the detector module 301 receiving X-rays, for guiding the X-rays to the corresponding two-dimensional discrete pixels; and further comprising grids 307 located between the detector module 301 and the collimator plate 302, for blocking the X-rays emitted to the gaps 306.