SiPM Non-Linearity Correction in Multiplexed Radiation Detectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
SiPM nonlinearity in multiplexed radiation detectors, particularly in PET systems, leads to degraded energy resolution due to varying photon flux density across the photosensor, which is not adequately corrected by existing methods that apply a single non-linearity correction based on the identified crystal-of-interaction.
Innovation Solution
A method is introduced to determine correction factors for each cell location in the photosensor array, using optical or analog electronic multiplexing, by generating gamma rays of specific energies, acquiring signal values, determining relative positions, and calculating average total signal values to derive correction factors that account for the non-linear relationship between signal and energy values, allowing for sub-pixel or continuous non-linearity corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single non-linearity correction is applied based on the identified crystal-of-interaction, then the correction process is simple, but the energy resolution is degraded due to varying photon flux density across the photosensor
Solution Approach 1:
The patent divides the photosensor surface into multiple regions (e.g., central region and peripheral regions) and applies different non-linearity correction factors to each region. This segmentation allows the correction to account for varying photon flux densities across different areas of the photosensor, thereby improving energy resolution without requiring a single complex correction model for the entire surface.
Solution Approach 2:
The patent implements location-dependent non-linearity corrections by determining the interaction location within the photosensor and applying region-specific correction factors. This local quality approach ensures that each region receives the appropriate correction tailored to its specific photon flux characteristics, improving overall measurement precision while maintaining manageable system complexity.
2Device complexity
If optical or analog electronic multiplexing is used to reduce the number of electronics channels, then the device complexity is reduced, but the non-linearity correction becomes more challenging due to varying photon flux distribution
Solution Approach 1:
The patent performs preliminary non-linearity correction by determining correction factors for different regions of the photosensor before actual gamma ray detection and measurement. This preliminary characterization of the photosensor's non-linear response across different regions allows for accurate correction during data acquisition, simplifying the measurement process while maintaining high precision despite using multiplexing.
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 approach improves energy resolution by providing more accurate non-linearity corrections, reducing scatter fraction and enhancing image quality in PET imaging systems.
Implementation Method 1
a scintillation array of crystal elements... acquiring, for each of the at least one nonlinear photosensor, a corresponding signal value generated by the at least one nonlinear photosensor in response to receiving scintillation light emitted by at least one crystal in the array
Data Source
AI summary
A system and method for determining correction factors used to determine energy of an event detected by a gamma ray detector having nonlinear photosensors arranged over a scintillation array of crystal elements, the gamma ray detector using optical multiplexing or analog electronic multiplexing. The method includes acquiring, for each nonlinear photosensor, a signal value generated by the nonlinear photosensor in response to receiving scintillation light emitted by a crystal in the array of crystal elements in response to arrival of a gamma ray; and determining a relative position of the event, the relative position being one of a predetermined number of cell locations, the predetermined number of cell locations being greater than a number of crystal elements in the array of crystal elements; and determining, for each cell location, a correction factor based on an average total signal value and a predetermined energy value of the gamma ray.