Field-Shaped Localizer Assembly for Accurate EM Instrument Tracking
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Solution Overview
Problem
Current navigation systems using electro-magnetic fields for tracking instruments in surgical and other procedures face limitations in accuracy and reliability due to the limited volume coverage and interference from external conductive materials, which can affect the precision of instrument location determination.
Innovation Solution
A localizer system comprising a transmitting coil array and a field shaping assembly that generates diverse, orthogonally distributed magnetic fields, allowing for improved tracking accuracy by mitigating external conductive material interference and expanding the navigable volume, even when positioned in close proximity to conductive structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transmit coils are positioned on a flat plane to reduce intrusiveness, then ease of operation and non-intrusiveness are improved, but field diversity and measurement precision deteriorate
Solution Approach 1:
A field shaping assembly is introduced as an intermediary component between the flat transmit coil array and the tracking volume. This assembly includes magnetic permeable materials and conductive materials that actively shape and diversify the magnetic field vectors, transforming the limited field distribution from flat coils into a diverse three-dimensional field pattern suitable for accurate tracking
Solution Approach 2:
The system changes the physical and magnetic parameters of the field by using materials with different magnetic permeabilities and electrical conductivities. The field shaping assembly modifies field strength, direction, and distribution parameters to achieve diverse orthogonal vectors throughout the tracking volume while maintaining the flat configuration of the transmit coils
2Volume of stationary object
If transmit coils are positioned close to the patient to expand navigable volume, then navigable volume is improved, but interference from external conductive materials increases
Solution Approach 1:
The field shaping assembly converts the harmful effect of external conductive materials into a beneficial effect by using similar conductive materials strategically positioned within the assembly. These materials are arranged to generate field vectors that complement and enhance the primary magnetic field, transforming potential interference into additional diverse field measurements
Solution Approach 2:
The field shaping assembly acts as a mediator between the transmit coils and external conductive materials. It controls and shapes the magnetic field to penetrate through or around external conductive structures, maintaining field diversity and measurement accuracy despite the presence of interfering materials in the vicinity
3Measurement precision
If multiple coils are used to generate diverse fields, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The field shaping assembly is segmented into multiple functional components including magnetic permeable elements and conductive elements arranged in specific patterns. Each segment contributes to shaping specific aspects of the magnetic field, allowing complex field diversification to be achieved through modular, manageable components rather than requiring an equally complex coil array
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 enhances the accuracy and reliability of instrument tracking by creating a diverse and orthogonal magnetic field distribution, effectively reducing interference from external conductive materials and expanding the navigable volume, thereby improving the precision of instrument location determination in surgical and other procedures.
Implementation Method 1
an instrument or object may be tracked by measuring an effect of a magnetic field on a sensor coil. The sensor coil may include a conductive material that is placed within a magnetic field where a current is induced on the coil.
Implementation Method 2
a field shaping assembly that is configured and is operable to transmit one or more diverse magnetic field or fields. The diversity of one or more fields is generated even though a plurality of coils of the TCA are positioned on a substantially flat plane.
Data Source
Figure 1
Figure 2A~2B
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AI summary
Disclosed is a localizer system. The localizer system may be incorporated into a navigation system for tracking a tracking device. Generally, the localizer may include a transmitting coil array and a field shaping assembly.