Dermal Reaction Quantification via Absorption and Scattering Coefficients

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Solution Overview

Problem

Current methods for calculating dermal reaction quantification indicators are not precise, often resulting in false positives or false negatives, due to incomplete consideration of chromophore concentrations and the distinction between absorption and diffusion coefficients.

Innovation Solution

A method and system that utilize a spectrometer and optical fibers to measure backscattered radiation, calculating absorption and scattering coefficients, and then determine chromophore concentrations to accurately quantify dermal reactions by accounting for multiple chromophores and their differences between healthy and reacted skin areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If current methods calculate dermal reaction indicators using limited chromophore considerations, then the calculation process is simple, but the measurement precision deteriorates resulting in false positives and false negatives

Engineering Contradiction:
Improvedermal reaction quantification accuracyVSAvoidcalculation method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the dermal reaction analysis by separating the calculation into distinct components: absorption coefficient determination, scattering coefficient determination, and their respective chromophore contributions (melanin, oxyhemoglobin, deoxyhemoglobin, water). This segmentation allows each parameter to be calculated independently with appropriate spectral ranges, improving overall measurement precision while maintaining a systematic approach to the complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces multiple spectral parameters including absorption coefficient μa(λ), scattering coefficient μs(λ), and their derivatives with respect to wavelength. By utilizing these parameter changes across different wavelength ranges (450-800nm for absorption, 650-800nm for scattering), the method achieves higher quantification accuracy through multiple independent measurements rather than a single composite value

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple chromophore concentrations are considered for accurate quantification, then the measurement precision improves, but the calculation time increases

Engineering Contradiction:
Improvechromophore concentration accuracyVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the spectral analysis into separate wavelength ranges for different chromophores: 450-800nm for absorption coefficient (affecting all chromophores), 650-800nm for scattering coefficient, and specific ranges for individual chromophore calculations. This segmentation allows parallel or sequential processing of each chromophore contribution, reducing overall calculation time while maintaining comprehensive multi-chromophore analysis

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent calculates absorption and scattering coefficients using spectral data from specific wavelength ranges that are optimized for each parameter. By using partial spectral ranges (e.g., 650-800nm for scattering instead of the full 450-800nm range), the method reduces the computational burden while still achieving accurate chromophore concentration measurements through the selective application of appropriate spectral windows

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If absorption and scattering coefficients are distinguished and both are measured, then the measurement precision improves, but the device complexity increases requiring separate measurement procedures

Engineering Contradiction:
Improveoptical coefficient differentiation accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a single spectrometer that performs multiple functions: measuring both absorption coefficient μa(λ) and scattering coefficient μs(λ) from the same backscattered radiation spectrum. The device achieves multi-functionality by processing the spectral data through different calculation algorithms for each coefficient, eliminating the need for separate measurement devices or procedures while maintaining high measurement precision for both parameters

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If comprehensive chromophore analysis is performed to reduce diagnostic errors, then the reliability improves, but the productivity decreases due to extended measurement and calculation time

Engineering Contradiction:
Improvediagnostic accuracyVSAvoidreaction assessment speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the comprehensive chromophore analysis into independent calculation modules for each chromophore (melanin, oxyhemoglobin, deoxyhemoglobin, water) using specific spectral ranges. This modular segmentation allows for optimized calculation algorithms for each chromophore type, reducing the overall computational time while maintaining the comprehensive multi-chromophore analysis necessary for high diagnostic reliability and reduced false positives/negatives

Inventive Principle:
Principle #1Segmentation

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

This approach improves the accuracy of dermal reaction quantification, reducing diagnostic errors and enabling earlier and more reliable assessment of skin reactions, such as those from allergens or antibodies, with a lower error rate compared to existing methods.

Implementation Method 1

the measurement, using a spectrometer, of the spectrum of backscattered radiation from the skin following the illumination of said area to be characterized

Methodology Applied
Scientific EffectBackscattering: Scattering

Implementation Method 2

the illumination of a skin area to be characterized via an excitation light beam emitted by a light source

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

the measurement, using a spectrometer, of the spectrum of backscattered radiation from the skin

Methodology Applied
Scientific EffectSpectroscopy: Absorption Spectroscopy

Implementation Method 4

based on the assumption that the attenuation of light during its propagation through the skin follows Beer-Lambert's law

Methodology Applied
Scientific EffectBeer-Lambert's law: Absorption (EM radiation)

Implementation Method 5

the calculation, from the determined value(s) of the absorption coefficient, of the concentration of at least one chromophore of the skin

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentEP2762064B1Method and system for calculating an indicator for quantifying a dermal reaction of the skin of a living being
Publication Date: 2023.06.07 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2762064B1 patent drawingFigure 1~2
  • EP2762064B1 patent drawingFigure 3
  • EP2762064B1 patent drawingFigure 4

AI summary

The method involves illuminating (100) a skin zone to be characterized by a light beam outputted from a light source. A value of a diffusion coefficient of the zone to be characterized is determined (120) from a measured spectrum and a value of a wavelength of the light beam. A concentration of chromophoric substance e.g. water, of skin is calculated (130) from a value of an absorption coefficient. An indicator for quantifying a dermal reaction of the skin is calculated (140) based on the determined value of the diffusion coefficient according to the calculated concentration. The chromophoric substance is oxyhaemoglobin, deoxyhaemoglobin, and bilirubin. An independent claim is also included for a system for calculating an indicator for quantifying a dermal reaction of skin of a living being.