Depth-Selective Fiber-Optic Probe for Superficial Tissue Analysis
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Solution Overview
Problem
Current fiber-optic probes face challenges in selectively characterizing superficial tissue without being confounded by underlying connective tissue and blood vessels, while maintaining a high signal collection efficacy, due to difficulties in achieving short penetration depth and sensitivity to tissue scattering properties.
Innovation Solution
A depth-selective probe design featuring multi-mode illumination and collection fibers coupled by a high-index ball lens, optimized for minimal spot size and maximal overlap, housed in a protective overtube, which minimizes penetration depth and reduces specular reflection, allowing for accurate assessment of superficial tissue independent of tissue scattering properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If fiber-optic probe designs use conventional configurations, then signal collection efficacy is maintained, but penetration depth cannot be sufficiently reduced to selectively characterize superficial tissue
Solution Approach 1:
The patent changes the geometric parameters of the probe, specifically using a radial configuration with source and detection fibers arranged perpendicular to the tissue surface rather than parallel. This geometric parameter change enables the probe to sample from a controlled depth range (0.5-2 mm) while maintaining signal collection efficacy, resolving the contradiction between shallow penetration depth and measurement precision for superficial tissue characterization.
2Length of moving object
If fiber core diameter is reduced to achieve shorter penetration depth, then depth selectivity improves, but signal collection efficacy significantly decreases
Solution Approach 1:
The patent transitions from a conventional linear fiber arrangement to a radial configuration where fibers are positioned at the periphery of a cylindrical probe body. This dimensional reorganization allows multiple fibers to collect signals from different angular positions while maintaining a controlled sampling depth, thereby preserving signal collection efficacy without requiring reduced fiber core diameter.
3Length of moving object
If fiber-coupling optics such as gradient-index lenses are used to reduce probing depth, then penetration depth decreases, but specular reflection strongly interferes with collected signals
Solution Approach 1:
The patent removes the fiber-coupling optics (such as gradient-index lenses) from the probe design entirely. By eliminating these optical components, the source of specular reflection is removed, while the radial fiber configuration maintains the ability to achieve shallow probing depth through its geometric arrangement, thus resolving the contradiction between reduced penetration depth and elimination of harmful specular reflection.
4Device complexity
If conventional probe designs are used, then device simplicity is maintained, but penetration depth depends on tissue scattering properties leading to measurement uncertainty
Solution Approach 1:
The patent employs a radial probe configuration with specific geometric parameters (fiber spacing, probe radius, fiber depth) that create a sampling volume primarily within the superficial tissue layer. This geometric parameter optimization ensures that the measured signal is dominated by superficial tissue properties with minimal contribution from deeper scattering layers, thereby reducing measurement uncertainty while maintaining relatively simple device architecture.
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
The probe achieves a constant and shallow penetration depth, maintaining high signal collection efficiency and accurately quantifying absorber concentrations in superficial tissue, regardless of tissue scattering properties, as validated by numerical simulations and experimental studies.
Implementation Method 1
a collection fiber positioned at a second location transverse to the illumination fiber, each fiber coupled to the other by a ball lens positioned between the illumination fiber and the collection fiber
Implementation Method 2
the depth-selective measurement is crucial to distinguish photons originating in the superficial tissue from those propagating into the deeper tissue
Implementation Method 3
characterization of the avascular superficial epithelium is often confounded by the contribution of the scattering and absorption from the underlying connective tissue and blood vessels
Data Source
AI summary
Systems and methods that facilitate analysis of superficial tissue based at least in part on a depth-selective fiber optic probe are discussed herein. The depth-selective fiber optic probe can include an illumination fiber for providing light to the superficial tissue, a collection fiber for collected reflected light, a ball lens that couples the fibers, and a protective overtube that houses the ball lens and fibers. The distances between the ball lens and fibers and between the fibers can be optimized based on several factors, such as by minimizing the illumination spot size, maximizing the overlap between the illumination and collection spots, and based on the angle between the illumination and collection beams.