Mobile Magnetometer Surgical Probe With Rotation-Invariant Calibration
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Solution Overview
Problem
Existing metal detection devices in surgical settings lack precision in locating small metal objects like needles within a body cavity due to inadequate calibration for background magnetic field interference, especially in mobile probes, and cannot determine the object's size, shape, and orientation, posing risks during removal.
Innovation Solution
A magnetometer-based device with adjustable distal portion, actuators, accelerometers, and calibration methods to achieve rotational invariance, enabling precise detection of both magnetized and non-magnetized metal objects, including a method to transform raw magnetic field data into a spherical surface for accurate localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single point measurement and subtraction algorithms are used to remove background field values, then the device structure remains simple, but the measurement precision deteriorates significantly for mobile probes
Solution Approach 1:
The system performs preliminary calibration by measuring background magnetic field values at multiple predetermined locations before the actual detection. These pre-measured background values are stored and used during the detection phase to accurately subtract background interference, enabling precise detection of small metal objects like surgical needles without requiring complex real-time calibration mechanisms
Solution Approach 2:
The patent transitions from single-point measurement to multi-point spatial measurement by measuring background magnetic fields at multiple predetermined locations around the body cavity. This spatial dimensionality expansion allows the system to map and subtract background interference more accurately, improving detection precision for mobile probes that move through three-dimensional space
2Adaptability or versatility
If existing metal detection devices are used, then the basic detection function is provided, but the ability to determine object location, size, shape and orientation is lost
Solution Approach 1:
The system continuously monitors and processes magnetic field signals during probe movement, using feedback from the magnetometer to track changes in signal strength and direction. This feedback mechanism enables the system to determine not only the presence of metal objects but also their precise location, size, shape and orientation by analyzing how the magnetic field interacts with the object from different angles
Solution Approach 2:
The patent replaces simple mechanical detection with advanced signal processing techniques that analyze magnetic field variations. By processing the temporal and spatial patterns of magnetic field changes during probe movement, the system extracts comprehensive object characteristics including location, size, shape and orientation, transforming raw magnetic data into meaningful anatomical information
3Ease of operation
If mobile probes are used for detection, then the ease of operation improves, but the calibration accuracy deteriorates due to movement and rotation
Solution Approach 1:
The system performs all necessary background field measurements and calibration at predetermined locations before the actual detection begins. By completing calibration upfront at multiple fixed positions, the system eliminates the need for continuous calibration during probe movement, allowing the mobile probe to operate freely while using pre-computed calibration data for accurate background subtraction throughout the detection area
4Device complexity
If detection of magnetized metal objects only is implemented, then the device complexity remains low, but the ability to detect non-magnetized objects is lost
Solution Approach 1:
The patent makes the magnetometer system universal by enabling it to detect both magnetized and non-magnetized metal objects through a unified approach. By measuring background magnetic fields at multiple locations and analyzing signal variations during probe movement, the system can detect the magnetic signature of non-magnetized objects (such as surgical needles) just as effectively as magnetized objects, expanding detection coverage without requiring separate detection mechanisms
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 device provides precise localization and orientation of metal objects, reducing procedural time and costs by ensuring safe and efficient removal of misplaced surgical instruments.
Implementation Method 1
at least one magnetometer positioned within or on the distal portion, wherein the at least one magnetometer includes at least one sensor capable of sensing a magnetic field
Implementation Method 2
an accelerometer positioned within or on the distal portion... determining an absolute directionality or directional line, with respect to a horizontal plane
Data Source
AI summary
A magnetometer-based metal detection device and methods of use are described. The device includes a proximal portion, a central body and a distal portion, and at least one magnetometer positioned within or on the distal portion. The at least one magnetometer includes at least one sensor capable of sensing a magnetic field in three orthogonal axes. Also described is a method of calibrating the device to achieve rotational invariance, and a method of determining a directionality or directional line along which a target metal object lies.