Fluorescent Tracer Monitoring with Background-Separated Renal Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for monitoring renal function, such as serum creatinine concentration and exogenous marker compounds, are prone to inaccuracies due to various factors and lack real-time capability, while invasive methods introduce radiation and laborious sample handling, making them unsuitable for continuous bedside monitoring.
Innovation Solution
A non-invasive method using a dual-wavelength renal monitoring system that corrects for dynamic changes in tissue optical properties by incorporating diffuse reflectance measurements to enhance fluorescence measurement accuracy, allowing real-time renal function assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If exogenous marker compounds are used to monitor renal function, then real-time monitoring capability is achieved, but measurement precision deteriorates due to ex vivo handling of blood and urine samples
Solution Approach 1:
The patent replaces mechanical/chemical laboratory analysis methods with optical detection. By using fluorescent markers that emit light when excited, the system substitutes complex ex vivo sample handling with non-invasive optical measurements through tissue, enabling real-time monitoring without sacrificing precision
Solution Approach 2:
The patent introduces fluorescent markers as intermediaries between the renal function being measured and the detection system. These markers are injected into the patient and their fluorescence emission serves as a mediator that can be detected optically through tissue, bridging the gap between internal physiological processes and external measurement
2Device complexity
If autofluorescence background is not corrected, then device complexity is reduced, but measurement precision deteriorates due to tissue autofluorescence and excitation light leak-through
Solution Approach 1:
The patent performs preliminary background characterization by measuring autofluorescence and light leak-through components before or during the actual fluorescent marker measurement. This preliminary action enables subsequent subtraction of these interfering signals, improving measurement precision without significantly increasing device complexity
Solution Approach 2:
The patent segments the total detected signal into distinct components: autofluorescence background, excitation light leak-through, and fluorescent marker emission. By separating these components through spectral filtering and temporal gating, the system can isolate and measure the marker signal with high precision
3Ease of operation
If eGFR equations are used to estimate renal function, then ease of operation is improved, but measurement precision deteriorates due to unaccounted variance factors
Solution Approach 1:
The patent replaces complex eGFR calculation equations with direct optical measurement of fluorescent marker clearance. This substitution eliminates the need to input and process multiple demographic variables (age, sex, race, muscle mass) while providing more accurate and direct measurement of renal function
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
Provides accurate, real-time monitoring of renal function by correcting for tissue autofluorescence and excitation light leak-through, reducing uncertainty and improving the fidelity of renal decay time constant calculations.
Implementation Method 1
monitoring a time-varying fluorescence emitted from an exogenous fluorescent agent
Implementation Method 2
characterized by scattering and/or absorption of light
Implementation Method 3
characterized by scattering and/or absorption of light
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of monitoring a time-varying fluorescence emitted from a fluorescent agent from within a diffuse reflecting medium with time-varying optical properties is disclosed that includes providing at least two measurements obtained from a patient before and after administration of the fluorescent agent that includes an Flr meas signal detected adjacent to the medium by a filtered light detector during illumination of the medium by excitatory-wavelength light, and at least one DR signal selected from: a DR exmeas DR em , and DR em,filtered signal. The method further includes identifying a post-equilibration portion of the measurement data set and transforming each Flr meas signal within the post-equilibration portion of the measurement data set to an IF agent signal representing a detected fluorescence intensity emitted solely by the fluorescent agent from within the medium. The disclosed method includes removing the effects of leak-through of excitation-level light and removing the effects of autofluorescence from the Flr meas signal.