Fiber Optic Bragg Grating Sensors for Medical Instrument Positioning
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Solution Overview
Problem
Conventional technologies for minimally invasive medical procedures face limitations in accurately determining the 3-dimensional spatial position and temperature of elongate medical instruments due to hardware geometric constraints and electromagnetivity issues, necessitating an alternative solution for precise monitoring during interventions.
Innovation Solution
The integration of fiber optic Bragg grating sensors along the length of steerable catheters, which utilize diffraction gratings to measure strain and temperature by analyzing changes in reflected light and thermal expansion, enabling precise detection of position and temperature at distal portions of the instrument.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electromagnetic position sensors or thermocouples are used, then measurement capability is provided, but hardware geometric constraints and electromagnetivity issues limit utility for elongate medical instrument applications
Solution Approach 1:
The patent replaces conventional electromagnetic position sensors and thermocouples with fiber optic Bragg grating sensors. This substitution eliminates the problems of hardware geometric constraints and electromagnetivity issues by using optical rather than electromagnetic sensing mechanisms, enabling reliable measurement in elongate medical instrument applications
Solution Approach 2:
The patent changes the measurement parameter from electromagnetic field interaction to optical wavelength detection. By using Bragg gratings that reflect specific wavelengths of light based on strain and temperature, the system achieves measurement capability that is adaptable to the geometric constraints of elongate medical instruments
2Measurement precision
If fiber optic Bragg grating sensors are integrated along the length of steerable catheters, then measurement precision of strain and temperature is improved, but device complexity increases
Solution Approach 1:
The patent divides the catheter into multiple measurement sections, each equipped with Bragg grating sensors at specific locations. This segmentation allows precise local measurement of strain and temperature at multiple points along the catheter length, which when combined provides accurate 3-dimensional position and temperature data
Solution Approach 2:
The patent uses a single type of sensor technology (Bragg grating sensors) to perform multiple measurement functions - both position determination through strain measurement and temperature detection. This multi-functionality reduces overall system complexity compared to using different sensor types for different measurements
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 solution provides accurate and reliable monitoring of 3-dimensional spatial position and temperature, enhancing the precision and effectiveness of minimally invasive procedures by overcoming the limitations of existing technologies.
Implementation Method 1
by applying the Bragg equation (wavelength = 2 * d * sin(theta)) to an optical fiber, a so-called 'fiber optic' or 'optical' fiber Bragg grating ('FBG') is formed within the optical fiber
Implementation Method 2
FBG sensors or components thereof, available from suppliers such as Luna Innovations, Inc., of Blacksburg, Virginia
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A~4D
AI summary
A medical instrument system comprises an elongate instrument body (33) ; an optical fiber (12) coupled in a constrained manner to the elongate instrument body, the optical fiber including one or more Bragg gratings; a detector (15) operably coupled to a proximal end of the optical fiber and configured to detect respective light signals reflected by the one or more Bragg gratings; and a controller operatively coupled to the detector, wherein the controller is configured to determine a geometric configuration of at least a portion of the elongate instrument body based on a spectral analysis of the detected reflected portions of the light signals.