Micropattern GEM Detector for Compact Positron Tomography
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Solution Overview
Problem
Existing positron tomography devices are large-scale and expensive, making them unsuitable for use in lab mice due to their reliance on scintillator detectors and Photo Multiplier Tubes, which are costly and bulky.
Innovation Solution
A compact positron tomography device utilizing a micropattern gas electron multiplier (GEM) detector, arranged in a cylindrical shape with multiple layers and ring formations, replacing conventional scintillator detectors and PMTs, and incorporating a signal processing unit for efficient photon detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional scintillator detectors and Photo Multiplier Tubes are used, then detection capability is achieved, but device size becomes large and cost increases
Solution Approach 1:
The patent changes the fundamental detection parameters by replacing scintillator-based detection with direct gas ionization detection using GEM detectors. This parameter change enables compact device design while maintaining detection capability, as the GEM detector can directly detect photons without requiring large scintillator crystals and PMT assemblies.
Solution Approach 2:
The patent substitutes the mechanical scintillator-PMT system with an electronic gas-based detection system. The GEM detector uses electric fields within micropatterned holes to amplify electron signals from direct photon interaction with the gas medium, eliminating the need for mechanical scintillator crystals and vacuum tube PMTs, thereby reducing device size.
2Measurement precision
If conventional scintillator detectors and Photo Multiplier Tubes are used, then detection capability is achieved, but manufacturing cost increases
Solution Approach 1:
The patent employs GEM detectors that can be manufactured using standard semiconductor fabrication techniques, making them significantly cheaper than conventional scintillator-PMT systems. The micropatterned GEM foils can be produced in batches using photolithography and etching processes, reducing per-unit cost while maintaining detection performance.
Solution Approach 2:
The patent changes the detection parameter from scintillation light emission to direct gas ionization, eliminating the need for expensive scintillator materials and PMT assemblies. This parameter change enables the use of cost-effective GEM detectors that can be manufactured using standard semiconductor processes, significantly reducing overall system cost.
3Productivity
If the inspection target is moved during scanning, then imaging is performed, but errors increase and analysis becomes complex
Solution Approach 1:
Instead of moving the inspection target through the detector as in conventional PET scanners, the patent inverts the approach by keeping the target stationary and using the cylindrical GEM detector array to detect photons from multiple angles simultaneously. This inversion eliminates motion-related errors and simplifies signal analysis while maintaining imaging capability.
Solution Approach 2:
The patent transitions from a single-plane detector requiring target movement to a three-dimensional cylindrical detector array. This dimensional change enables simultaneous multi-angle detection without moving the target, improving measurement precision by eliminating motion errors while maintaining productivity through parallel photon detection from multiple directions.
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
Enables high-resolution, cost-effective imaging of lab mice without the need for physical movement, reducing errors and simplifying signal analysis, while being suitable for medical and biological laboratories.
Implementation Method 1
primary electrons are released into a gas by ionizing radiations
Implementation Method 2
drifted through an electric field to a collecting electrode for detection
Implementation Method 3
amplifying electrons which react with gas layer due to operating with an amplifying layer
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A positron tomography device using a micropattern detector is disclosed. The positron tomography device comprises: a micropattern gas detection device accelerating electrons so as to generate second ionized electrons; a lead-out strip through which an electrical signal is transmitted by the second ionized electrons; and a signal processing unit for processing the electrical signal detected in the lead-out strip arranged at a predetermined position, wherein a plurality of micropattern gas detectection decives is disposed in a ring shape, and the lead-out strip is disposed outside the micropattern gas detection device.