Time-Resolved Optical Measurement for Absolute Brain Chromophore Sensing
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Solution Overview
Problem
Existing technologies fail to effectively measure and analyze neural activity in the brain, specifically the oxidation state of CCO, due to its low concentration and broad absorption peak, making it challenging to determine absolute concentrations and changes in tissue function.
Innovation Solution
A wearable optical measurement system using time-correlated single-photon counting (TCSPC) and time-resolved near-infrared spectroscopy (TR-NIRS) to detect neural activity, incorporating a light guide and light diverter to measure absolute optical properties, enabling simultaneous detection of HbO2, HHb, and oxCCO concentrations, and neural activity across the entire brain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If time-correlated single-photon counting (TCSPC) is used to measure photon distribution, then neural activity detection capability is improved, but measurement precision of absolute chromophore concentrations deteriorates due to low CCO concentration and broad absorption peak
Solution Approach 1:
The patent segments the measurement process into multiple wavelength channels (e.g., 750nm, 805nm, 850nm) to separately probe different chromophore absorption characteristics. By dividing the spectral range into discrete measurement bands, the system can isolate CCO signal from hemoglobin interference, improving measurement precision while maintaining neural activity detection capability
Solution Approach 2:
The patent introduces an intermediary reference measurement approach using a phantom or calibration sample with known properties. This reference measurement serves as a mediator to establish the relationship between detected photon counts and absolute chromophore concentrations, enabling accurate quantification of low-concentration CCO despite its broad absorption peak
2Adaptability or versatility
If multiple chromophores (HbO2, HHb, CCO) are measured simultaneously, then tissue function assessment capability is improved, but crosstalk between hemoglobin and CCO measurements increases
Solution Approach 1:
The patent applies local quality by assigning different wavelength regions to different chromophore measurement objectives. Specifically, the system uses 750nm for hemoglobin measurement where hemoglobin has strong absorption, 805nm for CCO measurement where CCO's isosbestic point provides minimal hemoglobin interference, and 850nm for additional CCO measurement. This wavelength-specific allocation reduces crosstalk while enabling simultaneous multi-chromophore assessment
Solution Approach 2:
The patent performs preliminary action by implementing a preprocessing step that separates hemoglobin and CCO signals before final concentration calculation. The system first measures total absorption at multiple wavelengths, then uses predetermined separation algorithms (based on known absorption spectra) to decompose the composite signal into individual chromophore contributions, thereby reducing crosstalk in the final measurements
3Reliability
If absolute concentration of CCO is measured, then oxidative metabolism assessment is improved, but measurement reliability deteriorates due to significantly lower CCO concentration compared to hemoglobin
Solution Approach 1:
The patent changes measurement parameters by using multiple wavelengths specifically selected to maximize CCO detection sensitivity. The system employs 805nm (CCO isosbestic point) and 850nm wavelengths where CCO absorption characteristics provide optimal signal-to-noise ratio. By adjusting the wavelength parameters and measurement timing, the system achieves reliable CCO concentration measurement despite its low absolute concentration
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 system provides accurate, simultaneous measurement of HbO2, HHb, and oxCCO concentrations, offering a full picture of oxidative metabolism and neural activity, enhancing brain health monitoring and activity detection with improved comfort and compactness.
Implementation Method 1
a light guide configured to receive a light pulse from the light source and guide signal photons included in the light pulse toward a target within a body of a user
Implementation Method 2
a light diverter configured to redirect reference photons included in the light pulse toward a photodetector without the reference photons entering the target
Implementation Method 3
a photodetector configured to detect the signal photons and the reference photons and generate an output in response to detecting the signal photons and the reference photons
Implementation Method 4
The processing unit may determine a temporal distribution of the signal photons detected by the photodetector and determine a temporal distribution of the reference photons detected by the photodetector
Implementation Method 5
the two main physical phenomena that affect photon trajectory and, hence, photon arrival time are scattering and absorption
Implementation Method 6
photons that are not absorbed are scattered, and a portion of the scattered photons may be detected
Data Source
AI summary
An optical measurement system includes a detector configured to detect signal photons included in a light pulse after the signal photons enter a body of a user and are scattered by a target within the body and reference photons included in the light pulse, the reference photons being diverted to the detector without entering the body. The optical measurement system further includes a processing unit configured to determine a temporal distribution of the signal photons detected by the detector, determine a temporal distribution of the reference photons detected by the detector, and generate measurement data based on the temporal distribution of the signal photons and the temporal distribution of the reference photons.