Multi-layer CT Detector Array with Thin Photosensor Layer
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Solution Overview
Problem
The existing multi-layer CT detector arrays, particularly in the horizontal configuration, suffer from reduced image quality due to direct-conversion noise caused by exposure of photosensor arrays to a significant portion of the x-ray beam flux, leading to absorption and subsequent direct-conversion current, which degrades spectral resolution.
Innovation Solution
A multi-layer horizontal CT detector array is designed with at least one thin photosensor array layer positioned between two scintillator array layers, where the photosensor array layers are optimized to minimize direct-conversion current, with materials and thicknesses chosen to ensure less than 0.1% of the signal current is from direct-conversion, and are arranged to maximize x-ray traversal with minimal interaction, thereby reducing noise and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photosensor arrays are exposed to x-ray beam flux in a horizontal configuration, then the detector can detect radiation, but direct-conversion noise is introduced which degrades spectral resolution
Solution Approach 1:
A thin conversion layer is introduced as an intermediary between the x-ray beam and the photosensor array. This layer converts x-rays to visible light, which then excites the photosensor without direct x-ray interaction, thereby eliminating direct-conversion noise while preserving the detection function
Solution Approach 2:
The harmful direct-conversion pathway is extracted from the system by preventing direct x-ray exposure to the photosensor array. The conversion layer acts as a filter that removes the direct x-ray-to-electricity conversion path, allowing only light-mediated conversion to occur
2Adaptability or versatility
If a multi-layer detector array is assembled with numerous components, then functional requirements are met, but assembly complexity and time increase
Solution Approach 1:
Multiple detector layers are combined into a single integrated assembly where conversion layers and photosensor arrays are pre-aligned and coupled together. This merging reduces the number of separate assembly operations required while maintaining the multi-layer functional architecture
Solution Approach 2:
The conversion layer serves multiple functions simultaneously: it converts x-rays to visible light, acts as a physical barrier preventing direct x-ray exposure to photosensors, and provides structural support for the detector assembly. This multi-functionality reduces the need for additional separate components
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 configuration significantly reduces direct-conversion noise, enhancing image quality and spectral resolution by ensuring that less than 0.1% of the signal current is from direct-conversion, resulting in improved volumetric image data generation.
Implementation Method 1
The scintillator array receives the radiation and converts it to light
Implementation Method 2
the photosensor array receives the light and produces an electrical signal indicative thereof
Data Source
Figure 1
Figure 2-I
Figure 2-II
AI summary
An imaging system (100) includes a radiation sensitive detector array (110). The detector array includes at least two scintillator array layers (116). The detector array further includes at least two corresponding photosensor array layers (114). At least one of the at least two photosensor array layers is located between the at least two scintillator array layers in a direction of incoming radiation. The at least one of the at least two photosensor array layers has a thickness that is less than thirty microns.