Electromagnetic Sensor Integration for Accurate Fiber-Optic Pose Tracking
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Solution Overview
Problem
Existing tracking systems in medical procedures face challenges in accurately determining the pose and shape of instruments and anatomy due to offset electromagnetic sensors, which can lead to inaccurate measurements and reliance on ionizing radiation.
Innovation Solution
A hybrid electromagnetic-optical sensor system is employed, where electromagnetic sensors are integrated with fiber optic shape sensing to provide an absolute measure of pose, using Fiber Bragg Gratings and Rayleigh scattering for strain measurements, and are aligned with the fiber optic line to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic sensors are used for tracking, then pose information can be obtained, but measurement accuracy deteriorates due to sensor offset from the fiber optic line
Solution Approach 1:
The patent combines electromagnetic sensors with fiber optic shape sensing into a hybrid system. The electromagnetic sensors are integrated along the fiber optic line such that they share the same spatial reference frame, eliminating offset errors. This merging allows the system to leverage both electromagnetic tracking capabilities and fiber optic shape sensing, achieving accurate pose measurements without the offset problems of conventional separate systems.
Solution Approach 2:
The fiber optic line serves as an intermediary reference structure. The electromagnetic sensors are positioned relative to the fiber optic line, which provides a stable spatial reference. This intermediary approach allows the sensors to maintain accurate positioning without direct mechanical coupling, resolving the offset issue while preserving tracking functionality.
2Measurement precision
If conventional tracking systems are used, then instruments can be located, but reliance on ionizing radiation increases
Solution Approach 1:
The patent replaces conventional X-ray-based tracking systems with a hybrid electromagnetic-optical system. Instead of relying on ionizing radiation for instrument visualization and location, the system uses electromagnetic sensors to detect magnetic fields and fiber optic sensing to detect shape, eliminating the need for ionizing radiation while maintaining accurate instrument location capabilities.
Solution Approach 2:
The patent converts the potential harm of ionizing radiation into a beneficial non-ionizing measurement approach. By using electromagnetic sensors that detect magnetic fields and fiber optic sensors that detect shape changes, the system achieves accurate tracking without ionizing radiation, turning a harmful dependency into a safe alternative.
3Measurement precision
If electromagnetic sensors are wrapped around fiber optic line, then absolute pose measure is achieved, but device complexity increases
Solution Approach 1:
The patent segments the sensor system into discrete electromagnetic sensing elements distributed along the fiber optic line. Each segment can be independently positioned and calibrated, reducing the overall integration complexity. This modular segmentation allows the absolute pose measurement capability to be achieved through multiple simpler units rather than one complex integrated system.
Solution Approach 2:
The patent transitions from relative pose measurement to absolute pose measurement by adding a reference frame dimension. The electromagnetic sensors are calibrated to a known reference coordinate system, enabling absolute position and orientation determination. This dimensional addition of reference framing simplifies the measurement model while achieving absolute pose accuracy.
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 tracking of instruments and anatomy with reduced reliance on ionizing radiation, providing accurate pose and shape measurements through improved sensor alignment and multiplexing techniques.
Implementation Method 1
one or more segments of the fiber optic line comprise one or more Fiber Bragg Gratings to produce strain measurements
Implementation Method 2
a strain experienced by one or more segments of the fiber optic line is determined from Rayleigh scattering
Implementation Method 3
one or more electromagnetic sensors wrapped at least in part around one or more portions of the fiber optic line
Data Source
AI summary
A device comprising includes an insertable structure usable in a surgical theater, a fiber optic line extending through the structure, wherein a computer system is configured to determine a shape of the fiber optic line extending through the structure, and one or more electromagnetic sensors wrapped at least in part around one or more portions of the fiber optic line, wherein the computer system is configured to determine a position and orientation of the one or more electromagnetic sensors, wherein the computer system is configured to determine a shape and a position of the structure based on the determined shape of the fiber optic line extending through the structure and the determined position and orientation of the one or more electromagnetic sensors.