Ferrite Powder Coil Probe for Sub-150 Micron Navigation
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Solution Overview
Problem
Conventional navigable medical probes with diameters of 1 mm or more are limited in accessing small body parts such as lung extremities and certain blood vessels in the brain due to the difficulty in producing small enough magnetic cores for navigation coils.
Innovation Solution
A probe apparatus with a shaft and a tube containing separate ferrite powder granules, where the tube is fixed to the shaft and a coil is placed around it, using a method that involves heat shrinking or capillary action to introduce the granules into the tube, allowing for a smaller inner diameter and increased magnetic permeability, enabling navigation in smaller body parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional solid magnetic cores are used in navigation coils, then the probe diameter is 1 mm or more, but this prevents access to small body parts such as lung extremities and certain blood vessels in the brain
Solution Approach 1:
The patent replaces conventional solid magnetic cores with ferrite powder granules that are suspended in a liquid carrier within the coil structure. This porous, particulate approach allows the magnetic core material to be introduced into extremely small tubes (inner diameter less than 150 microns) that would be impossible to manufacture with solid cores, thereby enabling probe diameters below 1 mm while maintaining navigational functionality
Solution Approach 2:
The patent creates a composite magnetic core structure by combining ferrite powder granules with a liquid carrier material. This composite approach allows the magnetic properties to be distributed throughout the liquid-filled tube, enabling the coil to function with a flexible, miniaturized structure that can be inserted into small body lumens while maintaining sufficient magnetic permeability for navigation
2Volume of moving object
If the tube inner diameter is reduced to less than 150 microns to enable smaller probe diameter, then access to small body parts is enabled, but introducing and containing ferrite powder granules becomes more difficult
Solution Approach 1:
The patent uses a liquid carrier material to suspend and transport the ferrite powder granules into the small-diameter tube. The liquid acts as a hydraulic medium that can flow through the narrow tube during assembly, carrying the granules along, and then solidifies or is removed to leave the granules in place, solving the problem of introducing particulate material into extremely small spaces
Solution Approach 2:
The liquid carrier material serves as an intermediary substance that facilitates the introduction of ferrite powder granules into the small tube. The carrier temporarily holds the granules in suspension during the assembly process, allowing them to be introduced as a slurry or suspension rather than attempting to manually place individual granules, and then is removed or solidified to leave the granules properly positioned
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 solution enables the creation of probes with diameters less than 150 microns, enhancing the sensitivity of navigation coils and allowing for precise tracking and positioning within smaller anatomical structures.
Implementation Method 1
The coil is surrounded by a tube containing separate powder granules of a ferrite. The powder granules increase the magnetic permeability of the coil and increase the amplitude of the signals provided by the coil.
Implementation Method 2
A magnetic field sensor within the distal end of the probe generates electrical signals in response to these magnetic fields
Implementation Method 3
A probe apparatus with a shaft and a tube containing separate ferrite powder granules, where the tube is fixed to the shaft and a coil is placed around it, using a method that involves heat shrinking or capillary action to introduce the granules into the tube
Data Source
AI summary
In one embodiment, a probe apparatus includes a shaft having a distal end, a tube containing separate powder granules of a ferrite, the tube being fixed to the distal end of the shaft, a coil disposed around the tube, and electrical wires connected to the coil so as to read out a signal generated across the coil due to an externally-applied magnetic field.