3D Semiconductor Detector for Collimator-Free Gamma Imaging
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Solution Overview
Problem
Existing PET and SPECT systems for molecular imaging are limited by resolution and efficiency due to positron range and mechanical collimators, respectively, leading to suboptimal performance in detecting radioactive nuclides.
Innovation Solution
A 3D semiconductor detector system comprising a plurality of semiconductor sensors with integrated read-out circuitry and processor-based image reconstruction, capable of recording all interactions induced by gamma rays, including Compton scatter and photoelectric effects, to enhance efficiency and spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical collimator is used in SPECT systems to define incident directions, then spatial resolution is achieved, but detection efficiency deteriorates significantly with only about 1 out of 10^6 photons passed to the detector
Solution Approach 1:
The patent removes the mechanical collimator component entirely from the SPECT system. Instead of using a collimator to define incident directions, the invention uses a semiconductor detector that directly detects gamma rays and determines their origin through electronic positioning and signal processing, extracting the directional information without mechanical obstruction.
Solution Approach 2:
The patent replaces the mechanical collimator system with an electronic detection and positioning system. The semiconductor detector uses electronic circuits and processing algorithms to determine the incident direction of gamma rays, substituting mechanical means with electronic and computational methods.
2Productivity
If a mechanical collimator is used in SPECT systems, then spatial resolution is limited to around 10 mm due to the trade-off between efficiency and spatial resolution, but this limits the achievable spatial resolution
Solution Approach 1:
The patent removes the mechanical collimator component entirely from the SPECT system. Instead of using a collimator to define incident directions, the invention uses a semiconductor detector that directly detects gamma rays and determines their origin through electronic positioning and signal processing, extracting the directional information without mechanical obstruction.
Solution Approach 2:
The patent replaces the mechanical collimator system with an electronic detection and positioning system. The semiconductor detector uses electronic circuits and processing algorithms to determine the incident direction of gamma rays, substituting mechanical means with electronic and computational methods.
3Productivity
If PET systems are used for molecular imaging, then detection efficiency is improved, but spatial resolution deteriorates due to the positron range of 0.5-6 mm
Solution Approach 1:
The patent changes the fundamental detection parameter from detecting positron annihilation photons (PET) to directly detecting gamma rays from radionuclide decay. This parameter change allows for direct measurement of gamma ray incidence without the intermediate positron range limitation, improving spatial resolution while maintaining high detection efficiency.
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
The detector system achieves significantly higher efficiency and spatial resolution compared to prior art systems, with improved detection capabilities for radioactive nuclides by utilizing all interactions within the semiconductor material, overcoming limitations of traditional PET and SPECT systems.
Implementation Method 1
record all interactions induced by incident gamma rays in the semiconductor material, including Compton scatter and photoelectric effects
Implementation Method 2
record all interactions induced by incident gamma rays in the semiconductor material, including Compton scatter and photoelectric effects
Data Source
AI summary
A detector system for molecular imaging of a radionuclide comprises a 3D semiconductor detector comprising a plurality of sensor stacks of sensors made of a semiconductor material having an average atomic number Z below 40. A read-out circuitry connected to the pixels is configured to output, for each interaction induced by an incident gamma ray in the detector, a signal representative of a time, a position and an energy of the interaction in the detector. The interactions in the detector belonging to a same event induced by the incident gamma ray are predicted based on the output signals and used to estimate a direction of the incident gamma ray and reconstruct an image based on the estimated directions of incident gamma rays.