Handheld Probe for Magnetic Marker Localization
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Solution Overview
Problem
Current methods for marking potentially cancerous tissue for surgical removal face challenges in placing small, easily detectable markers deep within tissue without obscuring anatomical features on MRI images and minimizing pain and discomfort during insertion.
Innovation Solution
A handheld probe with a first and second sensor, including magnetometers and accelerometers, is used to detect a magnetic marker by calculating the difference in magnetic field strength between the sensors, allowing for precise location of the marker in three-dimensional space while balancing for hard and soft iron effects, and using a lookup table to determine distance and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic markers are placed deep within tissue, then detectability by external scanning devices is improved, but MRI image footprint increases obscuring anatomical features
Solution Approach 1:
The patent changes the magnetic properties of the marker by using specific magnet materials with controlled remanence values (0.8-1.2 T) and coercivity (800-1200 kA/m). This parameter optimization allows the marker to be detectable by external magnetometers while producing minimal artifact on MRI images, resolving the contradiction between detectability and MRI compatibility
2Object-affected harmful factors
If marker size is reduced to minimize pain during insertion, then insertion comfort is improved, but detection range and signal strength decrease
Solution Approach 1:
The patent compensates for reduced marker size by optimizing magnetic parameters - using materials with high energy product (BH)max ≥ 37.5 kJ/m³ and specific remanence/coercivity values. This allows small markers (≤ 2 mm diameter) to maintain sufficient magnetic field strength for detection while minimizing insertion trauma
Solution Approach 2:
The patent replaces mechanical detection methods with magnetic field-based detection using magnetometers. This substitution enables detection of very small markers through their magnetic signature rather than requiring larger physical dimensions, thus maintaining detection capability while minimizing insertion pain
3Measurement precision
If dual sensors are used to determine distance and direction, then location precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the sensing function into two separate magnetometer sensors positioned at different locations on the probe. Each sensor independently measures magnetic field strength, and the processor compares these readings to calculate distance and direction to the marker, achieving 3D localization through functional segmentation
Solution Approach 2:
The patent introduces a processor as an intermediary that receives output from multiple sensors and performs calculations to determine marker location. This intermediary component simplifies the overall system by centralizing the complex computation logic rather than requiring complex hardware integration
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
Enables accurate and minimally invasive detection of magnetic markers within the body, reducing pain and discomfort during the procedure while avoiding interference with anatomical features on MRI images.
Implementation Method 1
a first sensor, including a first magnetometer and a first accelerometer located in a handheld housing, a second sensor, including a second magnetometer and a second accelerometer
Data Source
AI summary
A probe including a first sensor having a first magnetometer and a first accelerometer and a second sensor having a second magnetometer and a second accelerometer is configured for determining the distance and direction to a marker. The marker may be magnetic and may be surgically inserted into a patient's body to mark a specific location. The probe may be used to locate the marker, thus identifying the location. The probe may include a microprocessor that receives an output from the first sensor and an output from the second sensor and determines the distance and direction to the marker.