Internal Tracker Position Tracking for Real-Time Brain Localization

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Solution Overview

Problem

Existing tracking systems for signal-emitting sources inside the body are invasive, lack accuracy, and are not suitable for real-time localization of sub-millimetric devices due to limitations in current imaging technologies and the need for bulky external 3D frames, which restrict patient comfort and surgical precision.

Innovation Solution

A tracking system using internal trackers secured by fixation elements with mapping and tracker elements, a control unit, and a unified internal referential for real-time localization, aligning medical images to minimize invasiveness and enhance accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a skull opening is made to access the brain, then surgical access is improved, but brain shift occurs due to cerebrospinal fluid leakage which falsifies the targeted operation site

Engineering Contradiction:
Improvesurgical accessVSAvoidtargeted operation site accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs pre-operative imaging and establishes a reference frame before any skull opening is made. Tracking markers are placed on the skull surface prior to surgery, and the reference coordinate system is defined in advance, allowing the system to compensate for any subsequent brain shift that occurs during the procedure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously tracks the position of tracking markers on the skull and updates the registration between the pre-operative images and the actual patient anatomy in real-time. This feedback mechanism allows dynamic compensation for brain shift, maintaining accuracy throughout the surgical procedure.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If skull opening size is decreased to reduce invasiveness, then patient safety and comfort are improved, but the skull layer becomes a barrier that increases signal attenuation and depth

Engineering Contradiction:
Improvepatient safety and comfortVSAvoidsignal localization accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The system replaces electromagnetic tracking methods with ultrasound-based tracking. Ultrasound waves can penetrate the skull bone effectively without significant attenuation, allowing accurate tracking of internal structures through the intact skull without requiring large openings or compromising signal quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the physical parameters of the tracking signal from electromagnetic waves to ultrasound waves, which have different propagation characteristics that allow them to penetrate bone tissue more effectively with less attenuation, thereby maintaining tracking accuracy while minimizing invasiveness.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a huge external 3D frame is used for neuro-navigation, then reference alignment is improved, but patient comfort deteriorates due to bulkiness, weight, and restricted movement

Engineering Contradiction:
Improvereference alignmentVSAvoidpatient comfort and movement freedom
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system extracts and eliminates the bulky external 3D frame structure from the neuro-navigation setup. Instead, it uses minimal tracking markers placed directly on the patient's skull and a portable ultrasound transducer, removing the heavy, restrictive frame while preserving the ability to establish and maintain reference alignment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system creates a virtual 3D reference frame through software processing of ultrasound images and tracking marker positions, replacing the physical external frame. This virtual reference system provides the same alignment functionality without the physical bulk and restrictions of a traditional external frame.

Inventive Principle:
Principle #26Copying

4Measurement precision

If magnetic field technology is used for tracking, then position accuracy around millimeter is achieved, but it is not appropriate for localizing sub-millimetric devices

Engineering Contradiction:
Improveposition accuracyVSAvoidsub-millimetric device localization capability
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The system replaces magnetic field-based tracking with ultrasound-based tracking. Ultrasound provides superior spatial resolution for sub-millimetric structures because the wavelength of ultrasound at medical frequencies is much smaller than magnetic field wavelengths, enabling precise localization of tiny devices and structures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the tracking modality from magnetic fields to ultrasound waves, altering the physical parameters of the tracking signal. Ultrasound frequencies and wavelengths are optimized for high-resolution imaging at depth, providing the sub-millimetric localization capability needed for modern microdevices while maintaining position accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4259024B1Position tracking system
Publication Date: 2025.09.17 ROBEAUTE
  • EP4259024B1 patent drawingFigure 1~3
  • EP4259024B1 patent drawingFigure 4~5
  • EP4259024B1 patent drawingFigure 6

AI summary

Signal tracking system comprising: - one fixation element (12) to be secured to a rigid body part of the patient surrounding a target body part, the fixation element (12) further comprising a mapping element (16), - one tracker element to be secured to the fixation element (12) to track, in real time, the internal tracker, - a control unit comprising a memory to store: o an internal referential (R), o one image displaying the target body part and one fixation element (12), wherein the control unit is designed to define, inside the internal referential (R), at least one 3D frame position attached to the at least one fixation element (12), and to precisely locate each point of the target body part, the control unit is further designed to precisely localize, in real time, the internal tracker inside the target body part.