Quantum Dot Scintillator for Flexible CT Detector
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Solution Overview
Problem
Current computed tomography (CT) detectors are costly and rigid due to the use of solid scintillation materials, which limits their shape and increases production time, and indirect conversion detectors require multiple layers that increase thickness and cost.
Innovation Solution
A radiation detection system using optically transparent, non-insulating encapsulate materials with nanometer to micrometer quantum dots embedded in porous particles, allowing for energy discrimination without increasing the amount of scintillation material or photosensitive area, and enabling a detector configuration that can conform to various shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If solid scintillation materials (full size crystals, ceramics, or garnets) are used in detectors, then the detector structure is rigid and stable, but the shape is limited and production cost increases
Solution Approach 1:
The patent segments the scintillation material into nanometer to micrometer sized quantum dots dispersed within a polymer matrix rather than using bulk solid crystals. This segmentation allows the detector to achieve flexible shapes while maintaining structural stability through the composite structure, resolving the contradiction between rigidity and shape adaptability
Solution Approach 2:
The patent uses composite materials by combining quantum dots with a polymer matrix to create a flexible scintillation layer. This composite approach maintains the stability and light-emitting properties of the scintillation material while enabling shape flexibility through the polymer component, directly addressing the contradiction between structural stability and shape adaptability
2Measurement precision
If multiple layers of different scintillation materials are stacked for energy discrimination, then energy discrimination capability is improved, but detector thickness and production cost increase
Solution Approach 1:
The patent applies local quality by incorporating different quantum dot compositions with specific bandgaps into different regions or combinations within the scintillation layer. This allows energy discrimination across multiple energy bands within a single thin layer, achieving the measurement precision of multiple layers without increasing detector thickness
Solution Approach 2:
The patent transitions from a vertical stacking approach (multiple layers in one dimension) to a compositional variation approach (different quantum dot materials in the same layer). By varying the quantum dot composition and bandgap within the planar dimension, energy discrimination is achieved without increasing the thickness dimension, resolving the contradiction between energy discrimination capability and detector thickness
3Reliability
If direct conversion materials like CZT are used, then X-ray radiation is directly converted to electrical signals, but manufacturing time and cost increase due to crystal growth requirements
Solution Approach 1:
The patent changes the physical state and size parameters of the conversion material by using nanometer to micrometer sized quantum dots instead of bulk crystals. This parameter change enables solution-based processing methods that are much faster than crystal growth, reducing manufacturing time while maintaining direct conversion efficiency through the quantum dot's inherent properties
Solution Approach 2:
The patent replaces the mechanical crystal growth process with a solution-based assembly process where quantum dots are dispersed and deposited in a polymer matrix. This substitution eliminates the time-consuming crystal growth step while achieving direct conversion functionality through the quantum dot's electronic structure, resolving the contradiction between direct conversion efficiency and manufacturing time
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 reduces production costs and time while enhancing detective quantum efficiency and spectral discrimination, allowing for efficient energy discrimination in CT systems without the need for multiple layers or rigid structures.
Implementation Method 1
X-ray radiation incident on a scintillator are absorbed by scintillating material thereof, which in turn emits light photons
Implementation Method 2
light photons that are detected by a photodiode, which in turn generates a signal indicative thereof
Data Source
Figure 1
Figure 2~3B
Figure 4~5
AI summary
A radiation detection system of an imaging system (100) includes a radiation sensitive detector array (112). The array includes a detector pixel with an optically transparent encapsulate material (114) with one or more particles (116) supporting one or more different scintillation materials (118), wherein each scintillation material is in the form of a nanometer to micrometer quantum dot. A method includes receiving radiation with a detector pixel, wherein the detector pixel includes an encapsulate with one or more quantum dots, wherein each of the quantum dots includes a scintillation material, generating, with the detector pixel, a signal indicative of the received radiation, and reconstructing the signal to construct an image.