Fiber Optic Shape Sensing for Gait and Catheter Tracking
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Solution Overview
Problem
Current fiber optic position and shape sensing technologies are limited in their ability to provide accurate and comprehensive monitoring of human motion, particularly in gait analysis and catheterization procedures, due to their bulkiness and inability to measure multiple points accurately, and they expose patients and medical staff to excessive radiation and contrasting fluids.
Innovation Solution
The implementation of fiber optic position and shape sensing systems integrated into garments such as trousers and tights, which use multiple optical fibers with fiber Bragg gratings to provide detailed spatial coordinates and shape information, and a system that reduces the need for X-ray radiation and contrasting fluids by correlating body envelope changes with internal architecture during medical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fiber optic cables are installed along robot appendages to provide shape and position sensing, then spatial coordinates and shape information can be obtained, but the system becomes bulky and difficult to wear or apply
Solution Approach 1:
The optical fiber is divided into multiple segments with fiber Bragg gratings at specific locations. Each grating segment reflects specific wavelengths to indicate position and shape at discrete points along the fiber, enabling distributed sensing without requiring a continuous complex sensor array.
Solution Approach 2:
The optical fiber serves multiple functions simultaneously: it acts as both the sensing element and the signal transmission medium. The same fiber that provides structural integrity also carries the shape and position information through its optical properties, eliminating the need for separate sensing components.
2Measurement precision
If multiple fiber Bragg gratings are spaced along the core to provide spatial coordinates, then shape sensing accuracy improves, but the fiber structure becomes more complex with multiple cores and gratings
Solution Approach 1:
The fiber is segmented into multiple sensing zones along its length, with fiber Bragg gratings positioned at specific intervals. Each grating segment independently measures local strain and position, providing distributed shape information without requiring a fully multi-core fiber structure.
Solution Approach 2:
Different sections of the optical fiber are equipped with fiber Bragg gratings at specific locations along the core to sense shape at critical points. The gratings are strategically positioned to monitor specific regions of interest, providing localized high-precision measurements where needed rather than uniformly across the entire fiber.
3Loss of information
If X-ray radiation and contrasting fluids are used to image internal body parts during catheterization, then internal architecture can be visualized, but health risks from radiation and fluid exposure increase
Solution Approach 1:
The optical fiber with fiber Bragg gratings acts as an intermediary sensing element that provides shape and position information about the catheter or robot appendage without requiring direct X-ray imaging of the entire field. This reduces the need for continuous high-dose radiation exposure while maintaining awareness of tool location and body envelope shape.
Solution Approach 2:
Instead of directly imaging the internal body architecture with high-dose X-rays, the system uses the optical fiber to create a simplified representation or copy of the catheter's position and shape. This indirect measurement approach provides sufficient location information without the harmful effects of comprehensive internal imaging.
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 continuous monitoring of human motion with reduced equipment burden, minimizes health risks by reducing radiation and fluid exposure, and provides real-time data for improved gait analysis and medical procedures.
Implementation Method 1
The fiber Bragg gratings 112 are designed to reflect particular wavelengths of light and to transmit the rest
Data Source
AI summary
Using a suitably constructed fiber optic cable and interrogation circuitry, the fiber optic cable can be positioned along an object to monitor its shape and the position of various points along the object thereon. Embodiments disclosed herein apply fiber optic position and shape sensing in various ways. In one embodiment, as subject's gait is monitored for analysis. In another embodiment, a tool is displayed moving within a patient's body. In an additional embodiment, the movement of a subject's head is tracked.