Magnetic Distortion Correction for Medical Localization Accuracy

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Solution Overview

Problem

Magnetic localization systems for medical devices within patients are prone to errors due to magnetic field distortions caused by metallic objects, leading to inaccurate positioning of catheters during procedures.

Innovation Solution

A system comprising a magnetic field emitter, medical device sensor coils, and an array of magnetic distortion sensors, with processor circuitry to detect and correct for distortions by calculating a transform that compensates for perceived and actual sensor locations, ensuring accurate positioning of medical devices within the magnetic field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic localization systems are used to position medical devices, then positioning capability is provided, but accuracy deteriorates due to magnetic field distortions from metallic objects

Engineering Contradiction:
Improvepositioning accuracyVSAvoidmagnetic field distortion
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary detection of magnetic field distortions using distortion sensors before conducting medical device localization. By detecting and characterizing distortions in advance, the system can compensate for their effects during subsequent positioning operations, thereby maintaining accuracy despite the presence of metallic objects

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors magnetic field distortions through distortion sensors and uses this feedback information to adjust and correct localization measurements in real-time. This closed-loop approach allows the system to compensate for distortions dynamically, preserving positioning accuracy even when metallic objects are present in the field

Inventive Principle:
Principle #23Feedback

2Measurement precision

If distortion sensors are added to detect magnetic distortions, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvelocalization accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the magnetic field monitoring function into separate distortion detection sensors and medical device sensors. This segmentation allows independent optimization of each sensor type and enables modular processing of sensor data, reducing overall system complexity while maintaining high measurement precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The distortion sensors act as intermediary elements that indirectly measure the effects of metallic objects without requiring direct interaction with them. This intermediary approach allows the system to detect and compensate for distortions without needing to physically remove or neutralize the harmful metallic objects, simplifying the overall system architecture

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively corrects for magnetic field distortions, enhancing the accuracy of medical device localization and reducing procedural errors by providing precise positioning data, even in the presence of metallic objects.

Implementation Method 1

Each of the magnetic distortion sensors sense the magnetic field proximate thereto, and output a second electrical signal indicative of the sensed magnetic field at the magnetic distortion sensor

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

The catheter, while within the magnetic field, senses the unique magnetic field at its location (e.g., by elements such as coils)

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 3

The externally generated magnetic field includes precise magnetic gradients (field lines) that are unique at every location within the field

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnet

Data Source

PatentEP3791785B1Magnetic field distortion detection and correction in a magnetic localization system
Publication Date: 2023.01.04 ST JUDE MEDICAL INT HLDG SARL
  • EP3791785B1 patent drawingFigure 1A~1B
  • EP3791785B1 patent drawingFigure 2
  • EP3791785B1 patent drawingFigure 3

AI summary

Various embodiments of the present disclosure identify and correct for magnetic field distortions within a magnetic field for localization of a medical device within a patient. Such magnetic field distortions, often associated with the intrusion of a metallic object into the magnetic field, may cause an unacceptable level of localization error which aspects of the present disclosure correct for.