Inverse Spectroscopic OCT for Sub-Diffractional Tissue Imaging
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Solution Overview
Problem
Current optical probing methods struggle to analyze sub-diffractional biological features in intact tissues due to limitations in spatial resolution and the inability to quantify full optical scattering properties, particularly in vivo.
Innovation Solution
The development of inverse spectroscopic optical coherence tomography (ISOCT) enables the quantification of tissue mass density correlation functions and full optical scattering properties at sub-micron spatial resolutions by analyzing spectral profiles and combining scattering and backscattering coefficients, allowing for detailed three-dimensional imaging of biological tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OCT imaging is used, then tissue microstructure can be imaged in situ with micron-scale resolution, but the spatial resolution is fundamentally limited by temporal coherence length which is typically greater than 1 μm and in commercial instruments greater than about 10 μm
Solution Approach 1:
The patent changes the temporal coherence length parameter by using a supercontinuum light source with a broad spectral bandwidth (450-950 nm), which reduces the coherence length to below 1 μm. This parameter change enables sub-diffractional spatial resolution while maintaining the ability to quantify optical scattering properties through spectral analysis of the backscattered light
Solution Approach 2:
The patent replaces conventional mechanical scanning and detection methods with spectral-domain optical coherence tomography that detects changes in the backscattered amplitude and phase of light across a broad spectrum. This substitution enables simultaneous acquisition of high-resolution spatial information and quantitative optical scattering properties without mechanical limitations
2Measurement precision
If fluorescent reporters are used for high-resolution imaging, then sub-diffractional objects can be resolved, but the method requires exogenous labels and cannot quantify tissue structures
Solution Approach 1:
The patent enables biological tissues to serve themselves by utilizing their intrinsic optical scattering properties and endogenous chromophores for contrast. The broad-spectrum light source excites natural tissue variations in scattering and absorption, eliminating the need for exogenous fluorescent reporters while providing both high-resolution imaging and quantitative measurement of tissue optical properties
Solution Approach 2:
The patent exploits natural variations in the optical scattering and absorption properties of tissue chromophores across the broad spectral range (450-950 nm). By analyzing wavelength-dependent changes in the backscattered light spectrum, the system achieves sub-diffractional resolution and quantitative tissue characterization without requiring external contrast agents
3Ease of operation
If back reflectance scheme is used for in vivo optical measurement, then non-contact imaging is achieved, but the ability to quantify full optical scattering properties is inhibited
Solution Approach 1:
The patent adds the spectral dimension to the conventional spatial imaging by detecting backscattered light across a broad wavelength range (450-950 nm). This spectral dimension provides additional information that enables quantitative determination of optical scattering properties while maintaining the non-contact back reflectance measurement geometry
Solution Approach 2:
The patent uses spectral analysis of the backscattered light to provide feedback about the optical scattering properties of the tissue. By measuring the wavelength-dependent attenuation and scattering of light, the system continuously monitors and quantifies tissue optical properties in real-time, enabling precise characterization while maintaining non-contact operation
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
ISOCT provides enhanced imaging capabilities with sub-diffractional sensitivity, enabling the detection of alterations in tissue structure that can serve as biomarkers for carcinogenesis and other disease states, and enhances image contrast without the need for exogenous contrast agents.
Implementation Method 1
a low-coherence light source that produces broadband optical waves with a coherence length less than 1 μm
Implementation Method 2
OCT detects changes in the backscattered amplitude and phase of light
Implementation Method 3
OCT is analogous to ultrasound B-mode imaging except reflections of low-coherence light are detected rather than sound
Implementation Method 4
obtaining image signal data for the biological tissue sample with spectroscopic optical coherence tomography
Data Source
AI summary
A method and system to measure and image the full optical scattering properties by inverse spectroscopic optical coherence tomography (ISOCT) is disclosed. Tissue is modeled as a medium with continuous refractive index (RI) fluctuation and such a fluctuation is described by the RI correlation functions. By measuring optical quantities of tissue (including the scattering power of the OCT spectrum, the reflection albedo α defined as the ratio or scattering coefficient μs, and the back-scattering coefficient μb), the RI correlation function can be inversely deduced and the full set of optical scattering properties can be obtained.