Interferometric NIR Spectroscopy With Multi-Channel Beat Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing near infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) methods for neuromonitoring are bulky, slow, and require additional devices, with DCS relying on optical phase information rejection, leading to incomplete data and heavy averaging.
Innovation Solution
An interferometric near infrared spectroscopy (iNIRS) system with multiple optical channels of different lengths to separate beat frequencies, enabling simultaneous data acquisition and processing without additional circuitry, utilizing wavelength swept emission and interferometric detection to combine sample and reference light for enhanced data extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple wavelengths are used for monitoring oxygenation and blood flow, then comprehensive brain monitoring is achieved, but the system becomes bulky and slow due to additional devices and heavy averaging
Solution Approach 1:
The patent combines NIRS and DCS into a single integrated system that uses a single light source and detector to simultaneously measure both optical properties (for oxygenation monitoring) and temporal fluctuations (for blood flow monitoring). This merging eliminates the need for separate devices and reduces system complexity while maintaining comprehensive monitoring capabilities.
Solution Approach 2:
The single light source and detector are designed to perform multiple functions: measuring both absorption/scattering properties for oxygenation and temporal fluctuations for blood flow. This multi-functionality allows the system to achieve comprehensive brain monitoring without requiring additional specialized devices for each measurement type.
2Reliability
If DCS uses temporal fluctuations of light to monitor blood flow, then non-invasive blood flow monitoring is achieved, but the system requires heavy averaging making it slow
Solution Approach 1:
The system continuously measures temporal fluctuations of light without requiring periodic heavy averaging. By maintaining continuous measurement and using the interferometric approach to extract both optical and dynamical properties simultaneously, the system achieves fast measurement speeds while maintaining reliable blood flow monitoring.
3Ease of operation
If NIRS and DCS use only light intensities, then simple measurement is achieved, but half the information about scattered light (optical phase) is rejected leading to incomplete data
Solution Approach 1:
The patent replaces intensity-only measurement with interferometric measurement that captures both amplitude and phase information. By using the interferometric approach, the system substitutes simple intensity detection with a more comprehensive detection method that preserves optical phase information, enabling extraction of both optical and dynamical properties from the same measurement.
4Measurement precision
If DCS requires additional devices for blood flow extraction, then accurate blood flow measurement is achieved, but the system becomes more complex and bulky
Solution Approach 1:
The patent merges the functional requirements of NIRS (optical property measurement) and DCS (blood flow measurement) into a single integrated system. By combining both measurement capabilities in one system with a single light source and detector, the patent eliminates the need for additional separate devices while maintaining accurate blood flow measurement through temporal fluctuation analysis.
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 iNIRS system provides rapid, comprehensive neuromonitoring by combining NIRS and DCS, obtaining more data per cycle with improved accuracy and efficiency, allowing for non-invasive brain imaging and analysis of optical and dynamical properties.
Implementation Method 1
Radiation at NIRS wavelengths is less easily absorbed by human skin (and also bones) than visible light, and so NIRS radiation may penetrate both skin and skull, and penetrate into brain tissue
Implementation Method 2
The detector is arranged to combine: the reference light with the first sample light to provide light signals at a plurality of first beat frequencies between the first sample light and the reference light
Implementation Method 3
Diffuse correlation spectroscopy (DCS) can be used to noninvasively monitor blood flow in the brain by measuring temporal fluctuations of the light re-emitted from the sample
Implementation Method 4
a light detecting arrangement comprising an interferometric optical detector
Data Source
AI summary
An interferometric near infrared spectroscopy, iNIRS, system comprising: a light emitting arrangement comprising a light source configured to provide wavelength swept emission of light; and a light detecting arrangement comprising an interferometric optical detector; the iNIRS system comprising a plurality of optical channels arranged to define; a first optical channel path arranged to extend: (i) between the light source and the object for delivering first sample light from the light source to the object, and (ii) between the object and the detector for delivering first sample light received from the object to the detector; a second optical channel path arranged to extend: (i) between the light source and the object for delivering second sample light from the light source to the object, and (ii) between the object and the detector for delivering second sample light received from the object to the detector; and a reference optical channel path arranged to extend between the light source and the detector for delivering reference light from the light source to the detector along a reference channel.