Sub-pixel Time Skew Correction for PET Gamma Ray Detectors
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Solution Overview
Problem
Conventional PET systems face challenges in achieving precise localization of annihilation events due to uncorrected time skews in gamma ray detectors, which degrade the temporal resolution and image quality, especially in time-of-flight PET applications.
Innovation Solution
A calibration method and module that utilize a pixelated scintillator array and photodetector array with subdivided pixels to estimate and correct time skews by exploiting light sharing between adjacent scintillator pixels, employing tunable delay units and environmental data models to adjust for intrinsic and external factors affecting timing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional gamma ray detectors are used without time skew correction, then the device complexity is reduced, but the measurement precision of temporal resolution deteriorates
Solution Approach 1:
The system performs self-calibration by using the light sharing between adjacent pixels to automatically determine and correct time skews without requiring external calibration equipment or complex intervention procedures
Solution Approach 2:
The calibration process merges the measurement of light sharing intensity with time skew determination, using the same detected photons for both spatial intensity distribution analysis and temporal calibration
2Measurement precision
If light sharing between adjacent pixels is exploited for calibration, then the measurement precision of time skew is improved, but the device complexity increases due to additional calibration procedures
Solution Approach 1:
The system uses feedback from the light sharing measurement between adjacent pixels to automatically adjust and correct time skew values, creating a self-regulating calibration mechanism
Solution Approach 2:
The calibration method changes the temporal parameter (time skew) based on the measured spatial parameter (light sharing intensity distribution), linking spatial and temporal characteristics for correction
3Measurement precision
If sub-pixel level detection is implemented, then the measurement precision of photon position is improved, but the device complexity increases due to pixel subdivision
Solution Approach 1:
Each photodetector pixel is segmented into multiple sub-pixels, allowing the system to determine the precise position of photo conversion by analyzing which sub-pixel detects the scintillation photons first
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 method provides accurate and fast calibration, significantly improving the temporal resolution of gamma ray detectors, leading to enhanced imaging precision and reduced errors in medical imaging devices like PET/CT and PET/MR systems.
Implementation Method 1
a pixelated scintillator array having multiple scintillator pixels for emitting scintillation photons at photo conversion positions in response to incident gamma rays
Implementation Method 2
a pixelated photodetector, PD, array having multiple PD pixels coupled to the pixelated scintillator array for determining a spatial intensity distribution of the scintillation photons
Data Source
AI summary
The present invention relates to a calibration method for a gamma ray detector (100) including a pixelated scintillator array (110) for emitting scintillation photons at photo conversion positions (94) in response to incident gamma rays (90), and a pixelated photodetector array (120) for determining a spatial intensity distribution of the scintillation photons. The present invention bases on the idea that using the concept of optical light sharing of scintillation photons, which are emitted in one element, i.e., one scintillator pixel (112) of the scintillator array (110) and distributed over multiple photodetector pixels (122) of the pixelated photodetector army (120), allows obtaining an estimate for the time skew between adjacent photodetector pixels (122). The present invention further relates to a calibration module (200) for a gamma ray detector (100) including a recorder (210) and a processing module (220) for performing the function of the above-explained method. Still further, the present invention relates to a gamma my detector (100) as well as to a medical imaging device (50) comprising this gamma my detector (100).