Laser Tissue Stone Differentiation via Fluorescence
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Solution Overview
Problem
During laser lithotripsy procedures, the reduced visibility in turbid water environments can lead to inaccurate targeting, where the laser may inadvertently damage surrounding tissue instead of the urinary stone.
Innovation Solution
A system utilizing a Light Emitting, Transmitting, and Detecting (LETD) system with multiple laser sources emitting reference and fluorescence excitation beams, combined with optical fibers and detectors, to accurately determine the distance and differentiate between urinary stones and surrounding tissue based on fluorescence and water absorption coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser lithotripsy is performed in turbid water environment, then stone fragmentation is achieved, but visibility is reduced leading to inaccurate targeting and potential tissue damage
Solution Approach 1:
The system performs preliminary identification of the target (stone vs. tissue) using fluorescence detection and distance measurement before activating the therapeutic laser. This preliminary action ensures accurate targeting and prevents accidental tissue damage by confirming the laser is aimed at the correct target before treatment begins
Solution Approach 2:
The system continuously monitors fluorescence signals and distance measurements during laser lithotripsy procedure. This real-time feedback allows the system to verify continued targeting accuracy and alert the operator if the laser inadvertently contacts tissue, enabling immediate correction to prevent tissue damage
2Measurement precision
If multiple laser sources and detectors are added to distinguish stone from tissue, then targeting accuracy is improved, but device complexity increases
Solution Approach 1:
The optical fiber serves multiple functions: it delivers the therapeutic laser beam to the target and simultaneously collects fluorescence signals and reflected light for detection. This multi-functionality reduces the need for separate components and minimizes system complexity while maintaining high measurement precision for stone-tissue differentiation
Solution Approach 2:
The system combines fluorescence detection, distance measurement, and therapeutic laser delivery into a single integrated probe assembly. By merging these functions into one compact unit rather than separate components, the system achieves high measurement precision for distinguishing stone from tissue while controlling overall device complexity
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 enables precise differentiation between urinary stones and tissue, reducing the risk of tissue damage and improving the accuracy of laser treatments by automatically adjusting lasing parameters based on real-time feedback.
Implementation Method 1
an optical fiber having a distal end and a proximal end, the optical fiber configured to receive laser light from the first and second laser sources at the proximal end, to emit the laser light out of the distal end, and to receive reflected laser light into the distal end
Implementation Method 2
a fluorescence light detector to measure intensity of light at a fourth wavelength fluoresced from a target in response to the emission of the fluorescence excitation laser beam
Implementation Method 3
a first wavelength can have a first water absorption coefficient higher than a second water absorption coefficient of the second wavelength
Data Source
AI summary
The present disclosure provides a method and system for distinguishing between a stone and a tissue based on fluorescence from the stone or the tissue. Multiple reference beams are projected on a target to determine the distance to the target. The intensity of a fluorescence excitation beam is measured in conjunction with the determined distance to calculate the luminescence of the target and therefore it is a valid target for therapeutic lasing. In case a valid target for therapeutic lasing is detected and a switch is actuated, the therapeutic lasing will be enabled. In case a valid target for therapeutic lasing is not detected and the switch is actuated, the therapeutic lasing will be immediately disabled. The fluorescence excitation beam is pulsed at a high intensity and low duty cycle to avoid blinding an endoscopic imager used in the procedure.