Magnetic Tracking Sensor Coordinate Correction via Impedance Reference

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing medical imaging systems face challenges in accurately and efficiently correcting inconsistent field-based location coordinates of skin patches during medical procedures, particularly due to metal interference and patient movement, which requires time-consuming re-registration of frames of reference.

Innovation Solution

An apparatus and software product that compute field-based and impedance-based location coordinates of skin patches, detect differences between these coordinates, and apply corrections to ensure accurate tracking of a magnetic tracking sensor within the body, without requiring system resets or disrupting ongoing procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If field-based location coordinates are used for tracking, then real-time position sensing is achieved, but metal interference and patient movement cause coordinate inconsistency and reduced reliability

Engineering Contradiction:
Improvereal-time position sensing speedVSAvoidcoordinate consistency
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent introduces impedance-based location coordinates as an intermediary reference system to mediate between the field-based tracking system and the actual anatomical positions. By using the impedance-based coordinates (derived from electrode positions on the patient's body) as a stable reference, the system can detect and correct drifts in the field-based coordinates caused by metal interference or patient movement, thereby maintaining coordinate consistency without sacrificing real-time tracking speed

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system continuously compares field-based location coordinates with impedance-based location coordinates to detect discrepancies. When differences exceed a threshold, the system generates correction values and applies them to the field-based coordinates. This feedback loop ensures that coordinate inconsistencies caused by external factors are automatically corrected, maintaining reliability while preserving real-time tracking capability

Inventive Principle:
Principle #23Feedback

2Measurement precision

If frame re-registration is performed to correct coordinate inconsistencies, then tracking accuracy is improved, but procedure time increases and productivity decreases

Engineering Contradiction:
Improvetracking accuracyVSAvoidprocedure efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent transitions from static frame registration (performed manually at discrete intervals) to dynamic continuous correction. The system automatically and continuously computes correction values by comparing field-based and impedance-based coordinates in real-time, applying corrections as needed without interrupting the procedure. This dynamic approach maintains high tracking accuracy while eliminating the time loss associated with manual re-registration operations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs self-correction by automatically detecting coordinate inconsistencies and generating correction values without requiring external intervention. The control console continuously monitors the relationship between the two coordinate systems and autonomously applies corrections to maintain tracking accuracy, eliminating the need for operators to perform time-consuming manual re-registration procedures

Inventive Principle:
Principle #25Self-service

3Measurement precision

If complex correction algorithms are implemented, then coordinate accuracy is improved, but computational intensity and device complexity increase

Engineering Contradiction:
Improvecoordinate correction accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the correction process into distinct modular components: (1) computing field-based coordinates from magnetic field signals, (2) computing impedance-based coordinates from electrode measurements, (3) comparing the two coordinate systems to detect differences, (4) generating correction values based on detected differences, and (5) applying corrections to field-based coordinates. This segmentation allows each module to perform a specific function with simple, well-defined computations, reducing overall computational complexity while maintaining correction accuracy

Inventive Principle:
Principle #1Segmentation

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 solution enables efficient and accurate correction of field-based location coordinates, improving tracking precision and reducing the time and computational intensity associated with re-registering frames of reference, thus enhancing the accuracy and reliability of medical imaging systems.

Implementation Method 1

at least one of the patches including a patch sensor configured to output a signal in response to a magnetic field applied to the body

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Implementation Method 2

to compute first impedance-based location coordinates of the at least one of the patches by delivering an electrical current to the electrode inside the body and measuring an impedance between the at least one of the patches and the electrode inside the body

Methodology Applied
Scientific EffectElectrical impedance measurement: Electrical Resistance

Data Source

PatentEP3138486B1Field-based location coordinate correction
Publication Date: 2022.01.26 BIOSENSE WEBSTER (ISRAEL) LTD
  • EP3138486B1 patent drawingFigure 1
  • EP3138486B1 patent drawingFigure 2
  • EP3138486B1 patent drawingFigure 3~4

AI summary

A method, using patches fixed to a surface of a body, the patches including respective electrodes in contact with the surface, and at least one of the patches configured to output a signal in response to a magnetic field applied to the body. Initially, the signal is processed to compute first magnetic locations and first electrical locations of the at least one of the patches. Subsequently, the signal is processed to compute second magnetic locations and second electrical locations of the at least one of the patches. A first relation is computed between the first magnetic and the first electrical locations, a second relation is computed between the second magnetic and the second electrical locations, and upon detecting a difference between the second and the first relations, a magnetic location correction is computed and then applied to track a position of a magnetic sensor inside the body.