DPET Energy Calibration via Pixel-Specific Correction Factors
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Solution Overview
Problem
Current methods for calibrating digital positron emission tomography (PET) detectors suffer from non-linearity in photon counts due to photodiode reset mechanisms, leading to poor energy resolution, especially in the 100 keV to 500 keV range, which affects the accuracy of scatter event rejection and image contrast.
Innovation Solution
A system and method that uses an energy linearity correction model with multiple parameters to linearize energy measurements of strike events, identify clusters and sub-clusters, and apply specific correction factors to improve energy resolution, distinguishing between non-scatter and scatter events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single logarithmic model is used to correct non-linearity in DPET detectors, then the correction process is simple, but the energy resolution becomes poor because individual pixels need different corrections and the model over-corrects the energy level from 100 keV to 500 keV range
Solution Approach 1:
The patent divides the detector into individual pixels and applies pixel-specific correction factors instead of a single uniform logarithmic model. Each pixel's non-linearity is corrected independently using calibration data, which resolves the over-correction issue in the 100-500 keV range while maintaining correction simplicity through automated per-pixel calibration.
Solution Approach 2:
The patent implements local quality correction by applying different correction factors to different regions (pixels) of the detector. Each pixel receives a customized correction based on its specific non-linearity characteristics, improving energy resolution locally across the entire detector array without requiring a complex global model.
2Ease of operation
If a uniform correction coefficient is applied to all gamma events, then the correction method is simple to implement, but the energy resolution becomes less precise for scatter events
Solution Approach 1:
The patent implements a dynamic correction system that adapts the correction factor based on the event type. Non-scatter events use one correction approach while scatter events use a different correction approach, allowing the system to optimize energy resolution for each event category while maintaining ease of operation through automated event classification and application of the appropriate correction.
Data Source
AI summary
A system (10) and method for energy correction of positron emission tomography (PET) event data by at least one processor. Event data for a plurality of strike events corresponding to gamma events is received. Each strike event is detected by a pixel of a detector module (50) and includes an energy and a time. The energy of the strike events is linearized using an energy linearity correction model including one or more parameters. Clusters of the strike events are identified based on the times of the strike events, and sub-clusters of the clusters are identified based on the pixels corresponding to the strike events of the clusters. Energies of the sub-clusters are corrected using a first set of correction factors, and energies of clusters including a plurality of sub-clusters are corrected using a second set of correction factors.