Optical Fiber Twist Detection for Medical Instruments
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Solution Overview
Problem
Conventional technologies for minimally invasive medical procedures lack effective methods to determine the 3-dimensional spatial positions and orientations of elongate instruments, such as catheters, due to geometric constraints and electromagnetivity issues, limiting their utility in real-time feedback and precision.
Innovation Solution
The use of optical fibers with Bragg gratings integrated into elongate instruments to provide real-time feedback on their dynamic shape, position, temperature, and stress or strain, allowing for precise monitoring and control through strain sensors and controllers that analyze reflected signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electromagnetic position sensors are used to measure 3-dimensional spatial positions, then position measurement capability is provided, but hardware geometric constraints and electromagnetivity issues limit utility for elongate medical instrument applications
Solution Approach 1:
The patent replaces electromagnetic position sensors with an optical fiber-based sensing system that uses light propagation and Bragg grating reflections to measure spatial positions and orientations. This substitution eliminates the geometric constraints and electromagnetivity issues associated with conventional electromagnetic sensors, enabling effective measurement along the entire length of elongate medical instruments like catheters.
Solution Approach 2:
The patent introduces optical fiber as an intermediary medium to transfer measurement information from the distal end of the instrument to the proximal end. The optical fiber acts as a flexible, electrically inert conduit that can navigate tortuous pathways within the body while carrying strain sensor data back to the control system, overcoming the limitations of direct electromagnetic sensing.
2Measurement precision
If optical fibers with Bragg gratings are integrated into elongate instruments to provide real-time feedback, then measurement precision and real-time monitoring capability are improved, but device complexity increases
Solution Approach 1:
The patent combines the optical fiber with the elongate instrument structure itself, integrating the strain sensors directly into the instrument wall or shaft. This merging approach allows the instrument to serve dual purposes: as both the therapeutic/diagnostic tool and as the sensing platform, thereby reducing overall system complexity despite the advanced measurement capabilities.
Solution Approach 2:
The optical fiber system is designed to perform multiple functions simultaneously: measuring spatial positions, determining orientations, monitoring temperatures, and detecting stress or strain along the instrument length. This multi-functionality consolidates what would otherwise require separate sensor systems into a single integrated platform.
3Measurement precision
If strain sensors are provided on optical fibers to indicate twist of the elongate body, then twist detection precision is improved, but the optical fiber becomes more susceptible to twisting effects
Solution Approach 1:
The patent employs feedback mechanisms where the strain sensors continuously monitor twist-induced deformations in the optical fiber, and this information is fed back to the control system. The controller uses this real-time feedback to compensate for twist effects, maintaining measurement accuracy despite the fiber's susceptibility to twisting during navigation through tortuous body pathways.
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
Enables accurate and precise monitoring of elongate instruments' 3-dimensional spatial positions and orientations, enhancing the execution of minimally invasive procedures by providing real-time feedback and improving precision and safety.
Implementation Method 1
The strain sensor is configured to indicate twist of the elongate body
Implementation Method 2
The controller is adapted to receive a reflected signal from the strain sensor provided on the optical fiber
Data Source
AI summary
An instrument system that includes an elongate body and an optical fiber is provided. The elongate body has a longitudinal axis and capable of being twisted about the longitudinal axis. The optical fiber is operatively coupled with the elongate body and having a strain sensor provided thereon. The strain sensor is configured to indicate twist of the elongate body.