Scintillation Pulse Sampling for PET Inter-Crystal Scattering
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Solution Overview
Problem
Existing PET systems face challenges in accurately collecting and correcting inter-crystal scattering events due to Compton scattering, leading to incorrect energy calculations and reduced sensitivity.
Innovation Solution
A method involving dual trigger thresholds and multi-voltage threshold sampling to identify effective scintillation pulses, followed by superimposition and further sampling to determine real single events, incorporating amplification and pulse fitting to restore accurate energy, time, and positional information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If independent sampling solution is used in each channel, then sampling simplicity is maintained, but scintillation pulses with small energy fail to be collected or incorrect pulses are collected
Solution Approach 1:
The patent merges scintillation pulses from multiple crystal channels by superimposing their waveforms. When pulses arrive within a coincidence time window, they are combined and processed together, allowing small-energy pulses that would be missed in independent channel processing to be detected through constructive superposition.
Solution Approach 2:
The sampling circuit is designed to process both individual channel pulses and superimposed pulses from multiple channels using the same hardware infrastructure. The multi-voltage threshold sampling approach provides universal functionality for detecting pulses of varying energies across different operational modes.
2Quantity of substance
If MVT method is used for small-energy pulses, then sampling coverage is improved, but energy calculation deviations increase
Solution Approach 1:
The patent employs multiple voltage thresholds in the sampling process. By comparing the superimposed pulse waveform against several threshold levels, the system can more accurately determine the pulse amplitude and corresponding energy, reducing calculation deviations that occur with single-threshold methods applied to small-energy pulses.
Solution Approach 2:
The system performs preliminary superimposition of scintillation pulses from multiple channels before applying the multi-voltage threshold sampling. This preliminary combining action ensures that small-energy pulses are amplified through constructive interference, making them sufficiently strong for accurate energy calculation in subsequent sampling stages.
3Adaptability or versatility
If gamma photons undergo Compton scattering, then detection coverage is expanded, but energy deposition accuracy deteriorates
Solution Approach 1:
The patent converts the harmful effect of Compton scattering, which causes gamma photons to deposit energy across multiple crystal channels, into a beneficial signal. By detecting and superimposing pulses from multiple channels within a coincidence time window, the system recovers the total energy information that would otherwise be lost due to scattering, improving both detection coverage and energy measurement accuracy.
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
Enhances the precision and sensitivity of scintillation pulse sampling by accurately distinguishing real single events from noise and scattering events, improving the reliability of PET system data.
Implementation Method 1
a scintillation detector including a scintillation crystal and a photoelectric conversion device coupled to the scintillation crystal
Implementation Method 2
a photoelectric conversion device coupled to the scintillation crystal
Implementation Method 3
since gamma photons may undergo Compton scattering during their travel, the energy of the gamma photons changes, and the direction shifts
Data Source
AI summary
A method and apparatus for processing scintillation pulses, and a device and a storage medium. The method includes: presetting two trigger thresholds, and respectively performing multi-voltage threshold sampling on at least two scintillation pulses based on the two trigger thresholds, to acquire first sampling data; based on the first sampling data, determining one or more effective scintillation pulses from among at least two scintillation pulses; superimposing the effective scintillation pulses, to acquire a target scintillation pulse; presetting multiple sampling thresholds, and performing multi-voltage threshold sampling on the target scintillation pulse based on multiple sampling thresholds, to acquire second sampling data; based on the second sampling data, determining whether the target scintillation pulse corresponds to a real single event; and if the target scintillation pulse corresponds to a real single event, based on the first sampling data and the second sampling data, determining event information of the real single event.