Pixel Cell Trigger State Sensing for Photon Integration Timing
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Solution Overview
Problem
Current radiation detection systems in PET imaging and microscopy face challenges in accurately integrating the number of optical photons and timing of light pulses, leading to errors in image resolution and gamma photon scattering rejection.
Innovation Solution
A radiation detection device with an optical detector pixel array and pixel cell trigger state sensing circuits generates a digital signal indicative of triggered or non-triggered pixel cells, allowing a summing unit to produce an analogue signal corresponding to the real-time number of triggered pixel cells, enabling real-time integration and timing of optical photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional integration units are used to compute the energy of incident gamma photons, then the integration process can be performed, but the timing precision and integration accuracy are degraded due to delayed signal processing
Solution Approach 1:
The patent segments the detection process by separating the timing function from the integration function. The timing unit generates timestamps based on the leading edge of the signal, while the integration unit separately computes the total energy by integrating the entire pulse. This segmentation allows timing to be determined early without waiting for complete pulse integration, thereby improving timing precision while reducing processing delay.
Solution Approach 2:
The timing unit performs preliminary action by generating the timestamp at the leading edge of the signal before the complete pulse integration is finished. This preliminary timing determination does not wait for the full energy integration to complete, thus eliminating the delay that would otherwise be required for accurate timing while maintaining measurement precision.
2Reliability
If energy integration is performed to reject scattered gamma photons, then scattering rejection is improved, but the system complexity increases due to additional processing requirements
Solution Approach 1:
The patent applies parameter changes by establishing a relationship between the integrated energy parameter and the timestamp parameter. By computing the ratio of integrated energy to timestamp (or using the timestamp as a reference point for the integration window), the system can dynamically adjust the energy window for scattered photon rejection. This approach maintains high scattering rejection accuracy while reducing system complexity by using existing timing and integration data in a combined manner rather than requiring separate complex processing systems.
3Measurement precision
If the integration window is extended to capture more optical photons, then the energy measurement precision is improved, but the timing resolution deteriorates due to pulse spreading
Solution Approach 1:
The patent implements dynamics by making the integration window adaptive rather than fixed. The integration window is dynamically adjusted based on the observed pulse characteristics and the timestamp. By using the timestamp (determined at the leading edge) as a reference point, the system can optimize the integration window duration for each pulse individually, capturing sufficient photons for accurate energy measurement while preventing excessive window extension that would degrade timing resolution due to pulse spreading.
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 provides more accurate and repeatable integration and timing of optical photons, improving image resolution and reducing errors in PET imaging systems by allowing faster decision-making on optical pulse validity and material properties analysis.
Implementation Method 1
the scintillator element converts the high energy gamma photon into a scintillation light pulse comprising a number of optical photons
Implementation Method 2
the electrical signal is generated by the optical detector
Implementation Method 3
each pixel cell is in communication with a pixel cell trigger state sensing circuit that is configured to generate a digital signal having either a first predetermined amplitude indicative of a triggered pixel cell, or a second predetermined amplitude indicative of a non-triggered pixel cell
Data Source
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AI summary
The invention relates to a radiation detection device for integrating the number of optical photons in a light pulse. A system, a method and a computer program product are also disclosed. The radiation detection device comprises an optical detector pixel array which has a plurality of pixel cells that can be triggered by optical photons, a plurality of pixel cell trigger state sensing circuits, and a summing unit. Each pixel cell trigger state sensing circuit generates a digital signal having either a first predetermined amplitude indicative of a triggered pixel cell, or a second predetermined amplitude indicative of a non-triggered pixel cell. The summing unit generates an analogue signal whose amplitude corresponds to the number of triggered pixel cells and thereby performs the desired integration. The analogue signal may further cause a timing unit to generate a timestamp when a predetermined accumulated optical photon count condition is met.