Sub-1 mm Ferrite-Core Probe Coil for Navigating Narrow Vessels
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Solution Overview
Problem
Existing navigable medical probes, such as guidewires, are limited by their diameter of 1 mm or more, restricting access to body parts like the lungs and brain vessels, and producing small magnetic cores for navigation coils is challenging due to conventional production methods.
Innovation Solution
A probe design with a shaft and a tube containing separate ferrite powder granules, a coil around the tube, and a biocompatible cover, where the granules are not sintered but bound with a binder, allowing for a diameter of 0.9 mm or less, and methods to introduce the granules into the tube, enhancing magnetic permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional sintering methods are used to produce magnetic cores, then magnetic permeability is improved, but probe diameter cannot be reduced below 1 mm
Solution Approach 1:
The patent changes the manufacturing method from sintering to using a binder material that sets at room temperature or with mild heating. This parameter change in the production process enables the creation of very small magnetic cores (less than 1 mm diameter) that maintain sufficient magnetic permeability for navigation without requiring high-temperature sintering processes.
Solution Approach 2:
The patent uses composite materials by combining magnetic powder with a binder material to form the magnetic core. This composite approach allows the magnetic core to achieve the necessary magnetic properties while being manufacturable in very small sizes that would be impossible with conventional sintering alone.
2Adaptability or versatility
If probe diameter is reduced to access small body parts, then access to lungs and brain vessels is improved, but magnetic core production becomes challenging
Solution Approach 1:
The patent changes the manufacturing parameters to enable production of magnetic cores in the sub-1mm size range. By using binder materials that can be applied and set at low temperatures, the process becomes feasible for producing the tiny magnetic cores required in probes designed to access small body parts like lung extremities and brain vessels.
Solution Approach 2:
The patent segments the magnetic core into a powder form mixed with binder material, rather than attempting to sinter a solid block. This segmentation approach allows the magnetic material to be distributed and bound in very small quantities, making production of sub-1mm cores practical and enabling access to previously unreachable body parts.
3Volume of moving object
If ferrite powder granules are used instead of sintered cores, then probe diameter is reduced, but magnetic permeability enhancement becomes difficult
Solution Approach 1:
The patent creates a composite magnetic core by combining ferrite powder granules with a binder material. This composite structure maintains and enhances magnetic permeability despite the reduced size and powder form, as the binder holds the magnetic particles in a configuration that preserves their collective magnetic properties throughout the probe's operational life.
Solution Approach 2:
The patent changes the magnetic core from a sintered solid to a bound powder structure, and changes the binding mechanism from high-temperature sintering to room temperature or mild heat setting of binder materials. This parameter change enables reduced probe diameter while maintaining magnetic permeability through the binder's ability to hold the magnetic particles effectively.
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 probe design includes a shaft with a tube containing separate ferrite powder granules, a coil around the tube, and a biocompatible cover, where the granules are not sintered but bound with a binder, allowing for a diameter of 0.9 mm or less, and methods to introduce the granules into the tube, enhancing magnetic permeability.
Implementation Method 1
The tube contains separate powder granules of a ferrite. The coil is disposed around the tube... The powder granules are not sintered but are bound together using a binder material
Implementation Method 2
A magnetic field sensor within the distal end of the probe generates electrical signals in response to these magnetic fields
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A probe apparatus (28) includes a shaft (60) having a distal end (62), a tube (64) containing separate powder granules of a ferrite, the tube (64) being fixed to the distal end (62) of the shaft (60), a coil (66) disposed around the tube (64), and electrical wires (82) connected to the coil (66) so as to read out a signal generated across the coil (66) due to an externally-applied magnetic field.