Sub-surface Fluorescence Imaging via Multi-wavelength Depth Resolution
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Solution Overview
Problem
Current sub-surface fluorescence imaging techniques face challenges in achieving depth-resolved imaging in optically turbid media, such as biological tissue, due to limitations in point-detection methods and the ill-posed nature of full 3-D reconstructions, which can be corrupted by uneven tissue surfaces and movement during long acquisition times.
Innovation Solution
A system and method for sub-surface fluorescence imaging using wide-field excitation at multiple wavelengths, where an excitation source emits light at different wavelengths causing fluorescence at varying depths, and a light detector captures fluorescence emissions to reconstruct depth-resolved topographical maps based on light transport models, allowing for the localization of buried fluorescing objects like tumors or blood vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full 3-D reconstruction using laminar optical tomography is performed, then complete depth-resolved fluorescence information is obtained, but the problem becomes ill-posed and data is corrupted by uneven tissue surfaces and movement during long acquisition times
Solution Approach 1:
The patent extracts only the essential depth information needed for surgical guidance rather than performing complete 3-D reconstruction. By using multiple excitation wavelengths to probe different depths and extracting depth-resolved fluorescence intensity ratios, the system obtains sufficient depth information without the complexity and instability of full tomographic reconstruction
Solution Approach 2:
The patent changes the parameter of excitation wavelength to selectively probe different tissue depths. By using at least two different excitation wavelengths with different penetration depths and measuring the ratio of fluorescence intensities, the system determines subsurface fluorescence location without requiring full 3-D reconstruction, thereby improving reliability while maintaining measurement precision
2Measurement precision
If point-detection methods are used for depth-resolved fluorescence, then depth information can be obtained through spectrum distortion or spatial resolution, but the method has limitations in surgical field applications
Solution Approach 1:
The patent creates a imaging system that can operate in both point-detection and wide-field imaging modes. The system uses multiple excitation wavelengths and measures fluorescence intensity ratios to determine depth, providing a universal solution that maintains measurement precision while being adaptable to surgical field requirements through flexible optical coupling options
Solution Approach 2:
The patent transitions from point-detection to wide-field imaging by illuminating a broader area with multiple wavelengths and capturing spatially-resolved fluorescence intensity ratios. This adds the dimension of spatial coverage while maintaining depth resolution through spectral-ratio analysis, making the system easier to operate in surgical fields
3Ease of operation
If wide-field imaging with broad-beam illumination is used, then the fluorescence pattern can be imaged across the field, but the method assumes the fluorescence source is point-like which is restrictive
Solution Approach 1:
The patent applies different excitation wavelengths to different depth zones within the tissue, with each wavelength selectively exciting fluorophores at specific depths based on its penetration characteristics. This local differentiation of excitation depths allows the system to handle arbitrary fluorescence source distributions without restrictive point-like assumptions, while maintaining wide-field imaging capability
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
Enables accurate depth-resolved imaging of sub-surface structures, providing topographical maps with depth information, which is crucial for surgical guidance and other biomedical applications by effectively penetrating and imaging beneath tissue surfaces.
Implementation Method 1
an excitation source for selectably emitting light at at least one of at least two excitation wavelengths or wavelength ranges at a target surface... each of the at least two excitation wavelengths or wavelength ranges causes fluorescing of at least one marker at a sub-surface depth
Implementation Method 2
Different wavelengths of light penetrate at different depths in turbid media if there is a wavelength dependence of optical attenuation
Data Source
AI summary
A system for sub-surface fluorescence imaging is provided, the system comprising: an excitation source for selectably emitting light at at least one of at least two excitation wavelengths or wavelength ranges at a target surface; and a light detector for detecting fluorescence emission wavelengths or wavelength ranges from the target surface; wherein at least one of the at least two excitation wavelengths or wavelength ranges causes fluorescing of at least one marker at a sub-surface depth, the emitted light at each of the at least two excitation wavelengths or wavelength ranges having different depths of optical penetration and causing fluorescing at respective different depths. A method for sub-surface fluorescence imaging is also provided, in some cases exemplified by a reconstruction of the sub-surface fluorescence topography.