TRFI System Pulse Shaping for Fluorescence Imaging
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Solution Overview
Problem
Current time-resolved fluorescence imaging (TRFI) methods are limited by the complexity and time-consuming nature of fluorescence lifetime extraction, especially when dealing with multi-exponential decay curves and noisy signals, which can lead to unreliable results when closely spaced lifetimes are involved.
Innovation Solution
A TRFI system that obtains images without the need for lifetime fitting, using a pulse-shaping illumination source circuit with an LED and stub line to generate a linear decay profile, allowing for simple and accurate fluorescence image acquisition through subtraction and division-based methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluorescence lifetime extraction using nonlinear least squares fitting is used, then fluorescence lifetime can be estimated, but the analysis becomes complicated and time-consuming
Solution Approach 1:
The patent extracts only the essential information needed for imaging (fluorophore distribution) without performing complete lifetime extraction. By using ratio-based methods, the system obtains imaging data while eliminating the need for complex lifetime fitting algorithms, thus reducing computational complexity while maintaining imaging capability
Solution Approach 2:
Instead of extracting lifetime from decay curves through complex fitting, the patent inverts the approach by using measured intensity ratios at different time points to directly calculate fluorophore distribution. This reversal eliminates the need for iterative fitting procedures and provides a more straightforward calculation path
2Adaptability or versatility
If multi-exponential decay curve fitting is performed, then multiple fluorophore lifetimes can be extracted, but the calculation time increases significantly
Solution Approach 1:
The patent performs partial analysis by measuring intensity ratios at specific time points rather than analyzing the complete decay curve. This partial measurement approach provides sufficient information for imaging multiple fluorophores while avoiding the computational burden of complete multi-exponential fitting, thus maintaining productivity
Solution Approach 2:
The patent changes the measurement parameters from continuous decay curve sampling to discrete time-point intensity ratio measurements. By selecting specific time points for measurement, the system can distinguish multiple fluorophores based on their different decay characteristics without requiring full curve fitting, thereby improving acquisition speed
3Reliability
If noise is present in fluorescence signal, then measurement is more realistic, but lifetime extraction becomes even more unreliable
Solution Approach 1:
The patent introduces intensity ratios at different time points as intermediary measurements rather than directly extracting lifetime from noisy decay curves. These ratio measurements serve as mediators that are less sensitive to noise, providing a more reliable pathway to determine fluorophore distribution without the full impact of noise on lifetime extraction
Solution Approach 2:
The patent performs preliminary measurements of intensity ratios at selected time points before attempting any lifetime extraction. This preliminary data collection provides a noise-resistant foundation for imaging that can be obtained quickly and reliably, even in the presence of significant signal noise
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 enables faster, more reliable time-resolved fluorescence imaging by eliminating the need for complex lifetime calculations, providing clear differentiation of fluorophores and reducing computational power requirements, while maintaining image quality and contrast.
Implementation Method 1
the illumination source comprises an LED and stub line configured for generating a linear decay profile
Implementation Method 2
The time-resolved fluorescence signal of a fluorophore is usually a mono-exponential curve
Data Source
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AI summary
A time-resolved fluorescence imaging (TRFI) system that images a target medium without lifetime fitting. Instead of extracting the lifetime precisely, the system images the fluorophore distribution to allow for a simple and accurate method to obtain the fluorescence image without lifetime-extraction for time-resolved fluorescence imaging. An illumination source circuit for TRFI is also disclosed that shapes the excitation pulse. In one embodiment, the illumination source comprises an LED and stub line configured for generating a linear decay profile.