Conformal Coil Array for Medical Tracking Distortion

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Solution Overview

Problem

Electromagnetic tracking systems in medical procedures are sensitive to distortion caused by electrically-conductive and ferromagnetic materials in medical components, leading to inaccurate tracking or failure, particularly in fluoroscopic and microscope-guided procedures, where conventional methods like distortion-mapping and spaced-mounting are either time-consuming or limit tracking range.

Innovation Solution

A conformal attachment of the electromagnetic receiver unit to the medical image-capture component, such as an X-ray image detector or surgical microscope, which integrates field-distorting effects into the coil array design, allowing for accurate tracking across a broader range without the need for extensive calibration or spacing that obstructs the component's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional spaced-mounting is used to reduce field distortion, then tracking accuracy is improved, but the tracking range is limited and the component operation is obstructed

Engineering Contradiction:

Improvetracking accuracyVSAvoidtracking range

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The receiver unit is mounted conformally on the surface of the image-capture component using a flexible substrate that conforms to the component's geometry. This allows the receiver to be positioned close to the component surface without being obstructed by it, enabling wide-angle tracking while maintaining accurate electromagnetic field measurements despite the proximity to distorting materials.

Inventive Principle:

Principle #30Flexible shells and thin films

2Measurement precision

If distortion-mapping is used to compensate for field distortion, then tracking accuracy is improved, but the process becomes expensive and time-consuming

Engineering Contradiction:

Improvetracking accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The receiver unit is extracted from the traditional rigid mounting configuration and repositioned conformally on the image-capture component surface. This extraction from conventional mounting constraints allows the system to achieve accurate tracking without requiring time-consuming distortion-mapping procedures, as the conformal mounting inherently accounts for the distorting effects of the component materials.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If the receiver unit is mounted close to the image-capture component, then the component operation is not obstructed, but field distortion from conductive materials increases

Engineering Contradiction:

Improvecomponent operationVSAvoidfield distortion

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A flexible substrate is used to mount the receiver unit conformally on the image-capture component surface. This flexible mounting allows the receiver to be positioned as close as possible to the component without rigid structural interference, enabling uninterrupted component operation while the conformal geometry accounts for nearby conductive materials in the electromagnetic field calculations.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The system changes the mounting parameters from rigid spaced mounting to conformal surface mounting. This parameter change allows the receiver to be positioned optimally on the component surface, and the system compensates for the resulting field distortion through updated mathematical models that account for the receiver's precise location relative to the conductive materials.

Inventive Principle:

Principle #35Parameter changes

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 approach enables accurate tracking of medical instruments and components over a wider range, reducing the necessity for expensive and time-consuming distortion-mapping procedures while maintaining effective field emission, thus improving the reliability and usability of electromagnetic tracking systems in medical settings.

Implementation Method 1

transmitter coil or coils emit quasi-static magnetic fields and receiver coil or coils measure the fields as received

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS7471202B2Conformal coil array for a medical tracking system

Publication Date: 2008.12.30 STRYKER EUROPEAN OPERATIONS HOLDINGS LLC

AI summary

Described herein are one or more implementations for reducing the effects of distortion caused by the distorters in medical image-capture components used in medical electromagnetic tracking system. Examples of a medical image-capture component include an X-ray image detector used in fluoroscopic image-guided medical procedures and a surgical microscope. With one or more implementations described herein, the electromagnetic receiver unit (or transmitter unit) is conformably attached to the medical image-capture component.