Structured Illumination Microscopy for Tissue Margin Analysis
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Solution Overview
Problem
Current intra-operative tools for tumor margin diagnosis during surgical tumor resections are time-consuming, expensive, and lack effective methods for quickly examining the microscopic properties of surgical margins, particularly due to issues with background fluorescence in conventional fluorescence microscopy.
Innovation Solution
A rapid optical sectioning specimen scanner using video-rate incoherent structured illumination microscopy with a high-speed digital spatial light modulator and CMOS camera technology, which provides high-resolution, optically-sectioned images of fluorescent samples, reducing out-of-focus fluorescence and allowing for large-area throughput imaging of fresh tissue samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional fluorescence microscopy with uniform illumination is used, then the entire field of view is illuminated, but significant background fluorescence is generated from out-of-focus fluorophores, degrading image contrast
Solution Approach 1:
The illumination is segmented into multiple structured patterns (e.g., stripes, grids) that selectively excite fluorophores in specific spatial regions. By dividing the uniform illumination into patterned segments, only in-focus fluorophores within the structured illumination regions are excited, while out-of-focus fluorophores remain unexcited or contribute minimally to the signal, thereby reducing background fluorescence and improving image contrast
Solution Approach 2:
The illumination intensity is made non-uniform and spatially varying through structured patterns. Different regions of the sample receive different illumination intensities and patterns, allowing selective excitation of in-focus fluorophores while minimizing excitation of out-of-focus fluorophores. This local variation in illumination quality enables background rejection while maintaining signal from the focal plane
2Object-generated harmful factors
If confocal microscopy is used to reject background fluorescence, then image contrast is improved, but specialized optics and rapid scanning mirrors are required, increasing cost and decreasing imaging speed
Solution Approach 1:
The mechanical scanning system and adjustable pinhole optics of confocal microscopy are replaced with a static optical system that uses structured illumination patterns. Instead of mechanically scanning the beam and adjusting pinholes, the invention uses projectors or spatial light modulators to create structured illumination patterns that achieve background rejection through optical sectioning, eliminating the need for complex mechanical components while maintaining contrast improvement
Solution Approach 2:
Multiple structured illumination patterns with different phases, orientations, or frequencies are sequentially projected onto the sample. By acquiring multiple images with periodic variations in the illumination pattern and combining them through computational algorithms, the system achieves optical sectioning and background rejection without requiring mechanical scanning, thereby simplifying the device while improving imaging speed
3Object-generated harmful factors
If confocal microscopy with raster scanning is used, then background fluorescence is rejected, but the field of view is small and imaging large areas requires time-consuming raster scanning
Solution Approach 1:
The large field of view is divided into multiple regions illuminated by different structured illumination patterns simultaneously or in rapid succession. By segmenting the illumination across the entire field of view rather than scanning point-by-point, the system can capture large areas much faster while maintaining the background rejection capability provided by structured illumination. Parallel acquisition of multiple regions enables rapid imaging of large tissue samples
Solution Approach 2:
Multiple structured illumination patterns are prepared and projected in advance across the entire field of view, allowing simultaneous or near-simultaneous acquisition of multiple image frames. This preliminary preparation of illumination patterns enables rapid sampling of large areas without the time-consuming sequential raster scanning, thereby improving productivity while maintaining optical sectioning capability
4Productivity
If rapid imaging is achieved with wide-field fluorescence microscopy, then imaging speed is improved, but out-of-focus fluorophores are excited, generating background fluorescence and degrading contrast
Solution Approach 1:
Multiple structured illumination patterns with different phases are projected in rapid succession, and the resulting images are combined through computational algorithms. This periodic variation in illumination patterns enables optical sectioning and background rejection while maintaining high imaging speed, as the entire field of view is illuminated in each frame rather than scanned point-by-point. The rapid acquisition of multiple phase-shifted patterns achieves both speed and contrast improvement
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 rapid, high-resolution imaging of fresh tissue samples during medical procedures, effectively isolating single nuclei and reducing background fluorescence, thus facilitating timely cancer margin assessment and reducing the risk of cancer recurrence.
Implementation Method 1
The tissue sample is prepared such that the sample will fluoresce under illumination
Data Source
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AI summary
Systems and methods are provided for evaluating a fresh tissue sample, prepared as to fluoresce under illumination, during a medical procedure. A structured light source is configured to project a spatially patterned light beam onto the fresh tissue sample. An imaging system is configured to produce an image from fluorescence emitted from the illuminated fresh tissue sample. A system control is configured to provide a human-comprehensible clinically useful output associated with the medical procedure.