Magnetically Permeable Catheter Shaft for 6 DOF Sensing
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Solution Overview
Problem
Existing medical devices with electromagnetic coil position sensors face challenges in detecting six degrees-of-freedom (6 DOF) due to space constraints, particularly in sensing rotation about the central axis, which limits their functionality in medical procedures.
Innovation Solution
The use of magnetically permeable shaft and sheath strips in medical devices, such as catheters and introducers, to enhance the detection of 6 DOF by varying the length and alignment of these strips, allowing for increased magnetic field interaction and improved sensing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electromagnetic coil sensor is mounted symmetrically on the medical device shaft, then the device can detect five degrees of freedom (3D position and 2D orientation), but the device cannot detect rotation about the central axis (roll), limiting it to 5 DOF sensing
Solution Approach 1:
The invention divides the single symmetric coil sensor into multiple asymmetric coil segments arranged at different angular positions around the shaft. Each coil segment detects magnetic field changes along a specific direction, and by combining signals from multiple segments, the system achieves 6 DOF sensing capability including roll detection.
Solution Approach 2:
The invention transitions from a symmetric coil configuration to an asymmetric arrangement where multiple coil segments are positioned at different angular orientations around the shaft. This asymmetric positioning allows each coil to sense magnetic field changes in unique directions, enabling detection of rotation about the central axis that was impossible with symmetric configuration.
2Measurement precision
If multiple electromagnetic coil sensors are added to detect six degrees of freedom, then complete 6 DOF sensing is achieved, but the space required on the device increases, creating design challenges
Solution Approach 1:
The invention combines multiple coil segments onto a single shaft structure, integrating them in a compact radial arrangement. The coils share common mounting infrastructure and magnetic field sources, reducing the overall volume compared to separate sensor assemblies while achieving 6 DOF detection capability.
Solution Approach 2:
The invention transitions from linear sensor placement to three-dimensional radial arrangement of coil segments around the shaft. By utilizing the circumferential dimension, multiple sensors are accommodated in a compact cross-sectional footprint rather than requiring extended linear space, enabling 6 DOF sensing within constrained device dimensions.
3Volume of moving object
If a symmetric coil configuration is used to minimize space usage, then the device maintains a compact design with open central lumen, but the device loses the ability to detect rotation about the central axis
Solution Approach 1:
The invention deliberately introduces asymmetry in the coil positioning around the shaft, with coils placed at different angular positions rather than symmetrically. This asymmetric arrangement breaks the rotational symmetry that prevented roll detection, while maintaining compact spatial footprint, thereby achieving both space efficiency and enhanced sensing versatility including 6 DOF detection.
Solution Approach 2:
The invention makes the sensor system multi-functional by enabling it to detect all six degrees of freedom (3D position, pitch, yaw, and roll) using a single integrated sensor assembly. The asymmetric multi-segment coil configuration provides universal sensing capability across all motion parameters, replacing the need for separate specialized sensors while maintaining compact design.
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 configuration enables accurate detection of the 6 DOF, including rotation about the central axis, within the constraints of medical device design, enhancing navigation and positioning during medical procedures.
Implementation Method 1
The use of magnetically permeable shaft and sheath strips in medical devices, such as catheters and introducers, to enhance the detection of 6 DOF by varying the length and alignment of these strips, allowing for increased magnetic field interaction and improved sensing capabilities.
Data Source
AI summary
Various embodiments of the present disclosure can include a catheter. The catheter can include an elongate shaft that extends along a longitudinal axis. The elongate shaft can include a shaft proximal end and a shaft distal end. A magnetically permeable shaft strip can be disposed along a particular shaft length of the elongate shaft. The magnetically permeable shaft strip can longitudinally extend along the elongate shaft.