Multiphoton Microscope Pixel Clocking for Uniform High-Speed Imaging
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Solution Overview
Problem
Existing multiphoton microscopes face limitations in achieving high-speed imaging with consistent image quality due to variations in the number of laser pulses per pixel, leading to inhomogeneous image intensity and quality issues that hinder diagnostic interpretation of tissue histology.
Innovation Solution
The system employs a pixel clock synchronized with laser pulses to ensure uniform pixel dwell times, uses a spinning polygon mirror for rapid scanning, optimizes laser repetition rates based on dye lifetimes, and minimizes pulses per pixel to maintain signal-to-background ratio, while incorporating optimized microscope configurations and detection filters for high-quality imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If resonant galvanometer is used for high-speed scanning, then scanning speed is improved, but image intensity uniformity deteriorates due to sinusoidal scan pattern causing large variation in pulses per pixel
Solution Approach 1:
The patent changes the scan pattern from sinusoidal to linear by using a spinning polygon mirror instead of a resonant galvanometer. This parameter change in the scanning mechanism eliminates the velocity variation inherent in sinusoidal motion, resulting in uniform pixel dwell times and consistent image intensity across the field of view while maintaining high scanning speeds.
Solution Approach 2:
The patent replaces the resonant galvanometer mechanical system with a spinning polygon mirror system. This substitution eliminates the sinusoidal motion characteristic of galvanometers and provides linear scanning motion, thereby resolving the contradiction between high-speed scanning and image intensity uniformity.
2Productivity
If pixel dwell time is reduced to increase scanning speed, then productivity is improved, but image quality deteriorates due to variation in number of laser pulses per pixel
Solution Approach 1:
The patent changes the relationship between pixel dwell time and laser pulse repetition rate by using a spinning polygon mirror with a specific number of facets. This parameter change ensures that each pixel receives a consistent number of laser pulses (e.g., 2-10 pulses) regardless of the reduced dwell time, thereby maintaining image quality while achieving high imaging speeds.
3Speed
If laser repetition rate is increased to reduce pixel dwell time, then scanning speed is improved, but pulse variation per pixel increases leading to intensity inhomogeneity
Solution Approach 1:
The patent synchronizes the spinning polygon mirror rotation frequency with the laser pulse repetition rate. This parameter synchronization ensures that as the laser repetition rate increases, the polygon mirror rotates at a corresponding speed to maintain a constant number of pulses per pixel, thereby preserving pulse consistency while enabling high-speed imaging.
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 efficient, high-quality imaging at high speeds, suitable for clinical diagnostics, by ensuring uniform pixel intensity and minimizing photobleaching, photodamage, and reducing costs through optimal dye usage.
Implementation Method 1
The generation of fluorescence in the sample occurs by the simultaneous absorption of two or more photons from the laser
Implementation Method 2
The generated fluorescence is typically collected back through the objective lens and directed to one or more detectors
Implementation Method 3
The light from the laser is focused by a microscope objective to a point inside the sample. This point is scanned across the sample by a system of mirrors placed upstream of the objective
Data Source
Figure 1A~1B
Figure 2
AI summary
The invention provides improved systems and methods for multiphoton microscopy including pixel clocking techniques for minimizing pixel integration time and providing consistent signal intensity with maximized imaging speeds. Various systems and method are described for optimizing laser repetition rate based on dye lifetime, combining polygonal mirror scanning and stage translation, using the laser pulse signal to time pixel collection, and minimizing laser pulses and dye usage based on signal to background ratios.