Fast Multiphoton Microscope With Pixel Clock Synchronization
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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 integer multiples of pixel dwell times, uses a spinning polygon mirror for rapid scanning, and coordinates a translational stage to minimize pixel-to-pixel variations, along with optimized laser repetition rates and dye concentrations to maintain signal-to-background ratio, while utilizing multiple detectors for efficient fluorescence collection.
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 replaces the resonant galvanometer's sinusoidal mechanical scanning motion with a polygon mirror that rotates at constant angular velocity. This substitution eliminates the non-linear scan pattern inherent to resonant galvanometers, providing uniform pixel dwell times and consistent image intensity across the field of view while maintaining high scanning speeds.
Solution Approach 2:
The patent changes the scanning mechanism from sinusoidal motion (resonant galvanometer) to uniform rotational motion (polygon mirror). By altering the motion parameter from accelerated/decelerated to constant velocity, the system achieves both high-speed scanning and uniform image intensity, resolving the contradiction between speed and precision.
2Productivity
If pixel dwell time is reduced to increase scan rate, then productivity is improved, but image quality deteriorates due to variation in number of pulses per pixel
Solution Approach 1:
The patent replaces the galvanometer-based scanning system with a polygon mirror rotation system that provides linear, uniform angular velocity. This mechanical substitution ensures that pixel dwell time remains constant even at high scan rates, preventing the variation in pulses per pixel that degrades image quality while maintaining high productivity.
3Speed
If high laser repetition rate is used to reduce pixel dwell time, then scanning speed is improved, but photobleaching increases due to excessive pulse density
Solution Approach 1:
The patent optimizes the laser repetition rate parameter to match the polygon mirror rotation speed and pixel dwell time. By coordinating these parameters, the system achieves high imaging speed while maintaining an appropriate number of pulses per pixel (typically 1-10 pulses), thereby reducing photobleaching compared to systems using excessively high repetition rates.
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 high-quality, high-speed imaging suitable for clinical diagnostics by ensuring uniform pixel intensity and minimizing photobleaching, thereby enhancing the practicality of multiphoton microscopy for large volume imaging.
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
uses a spinning polygon mirror for rapid scanning
Data Source
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.