Tissue Inspection System with Continuous Optical Calibration
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Solution Overview
Problem
Current interventional devices with optical fibers for tissue inspection require frequent calibration and are sensitive to environmental changes, limiting their usability and increasing costs due to stringent stability requirements, making them unsuitable for continuous and accurate tissue feedback during procedures.
Innovation Solution
A system with an elongated shaft containing an illumination fiber and a detection fiber, where the fibers share a common path and are connected via a plug with a different refractive index, allowing for continuous calibration and reducing the impact of environmental variations, combined with a phosphor element for enhanced light output and wavelength compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent calibration with reference spectrum is performed, then measurement precision is improved, but productivity deteriorates due to cumbersome workflow
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements at the distal end of the optical fiber before actual tissue inspection. A calibration reflectance spectrum is obtained by reflecting light from a calibration target (such as a diffuse reflector or tissue phantom) at the distal end, and this pre-obtained spectrum is stored for subsequent normalization. This eliminates the need for frequent manual recalibration during procedures, maintaining measurement precision while improving workflow efficiency.
2Measurement precision
If tight control over stability of all components in optical path is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by using the optical fiber itself to deliver both the illumination light to the calibration target and to retrieve the reflected calibration spectrum. The same fiber that may exhibit instability also serves as the measurement path, allowing the system to self-calibrate by normalizing the tissue spectrum with the pre-obtained calibration spectrum from the same fiber. This eliminates the need for separate stable reference paths and complex stability control mechanisms.
3Measurement precision
If large core fibers are used to ensure optical stability, then measurement precision is improved, but the ability to use smaller needles deteriorates
Solution Approach 1:
The patent replaces the mechanical approach of using large core fibers for stability with an optical/software-based solution. Instead of relying on physical fiber size for stability, the system uses diffuse reflectance spectroscopy with pre-obtained calibration spectra and normalization algorithms to achieve measurement precision. This substitution allows the use of smaller core fibers (enabling thinner needles) while maintaining measurement quality through computational correction rather than mechanical oversizing.
4Reliability
If continuous calibration is implemented, then reliability is improved, but use of energy increases due to continuous light source operation
Solution Approach 1:
The patent applies periodic action by performing calibration measurements at discrete intervals or at specific moments (such as at the beginning of a procedure or when needed) rather than continuously. The light source is activated only during these periodic calibration events and during actual tissue measurements, allowing the system to maintain reliability through regular calibration while significantly reducing energy consumption compared to continuous operation. The calibration spectrum obtained periodically is then used for normalization during subsequent measurements.
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 continuous and stable tissue inspection with reduced calibration needs, lower costs due to relaxed optical stability requirements, and the ability to use smaller, lower-cost fiber sizes, providing real-time feedback and improved biosafety with pulsed light sources.
Implementation Method 1
the plug is made of a second material having a second refractive index, wherein the second refractive index differs from the first refractive index so as to allow back-reflectance of light
Implementation Method 2
an element (52) with phosphor may be provided, wherein the phosphor may be excited by the light source so as to emit phosphorescence
Implementation Method 3
The illumination fiber is capable of transmitting light from the light source to its front surface and is capable of transmitting light in an opposite direction
Data Source
AI summary
A system for tissue inspection is provided, comprising a console (50) with a light source (64), a spectrometer (66), an optical switch (65) and a processing unit. The system further comprises an elongated shaft (10), wherein an illumination fiber (40), a plug (50) in front of the illumination fiber (40), and a detection fiber (41) is provided in the elongated shaft (10). The illumination fiber (40) is capable of transmitting light from the light source (64) to its front surface and is capable of transmitting light being back-reflected from the plug (50) to the optical switch (65). The detection fiber (41) is capable of transmitting light reflected from tissue in front of the distal end surface of the elongated shaft (10) to the optical switch (65). The optical switch (65) is configured to provide the back-reflected light to the spectrometer (66) for generating a reference spectrum and to provide the light reflected from the tissue to the spectrometer (66) for generating a diffuse reflectance spectrum. The processing unit is configured to generate a tissue spectrum by normalizing the diffuse reflectance spectrum with the reference spectrum.