Electromagnetic Tracking Error Compensation Tool
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Solution Overview
Problem
Electromagnetic tracking systems in medical environments face significant accuracy and reliability issues due to metal distortions caused by conductive or ferromagnetic objects, which limit their clinical utility and affect the precision of tracking medical instruments during procedures.
Innovation Solution
The system employs an electromagnetic field generator with an error compensation tool featuring a plurality of electromagnetic sensors arranged in a known geometric configuration, combined with an optical tracking sensor to generate distortion maps, allowing for accurate tracking by compensating for metal distortions and enabling the display of corrected positional and orientational data on imaging systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic tracking systems are used in medical environments with metallic objects, then tracking capability is provided, but measurement precision deteriorates due to metal distortions
Solution Approach 1:
The patent introduces an error compensation tool as an intermediary device between the electromagnetic field generator and the medical instruments being tracked. This tool contains sensors that measure the actual electromagnetic field distortions caused by metallic objects, and a processor that calculates correction factors based on these measurements. The correction factors are then applied to compensate for the metal distortions, thereby maintaining tracking accuracy in the presence of harmful metallic objects.
Solution Approach 2:
The system implements a feedback mechanism where sensors in the error compensation tool continuously monitor the electromagnetic field for distortions caused by metallic objects. The processor receives this feedback data and dynamically calculates correction factors that are applied in real-time to compensate for the detected distortions. This closed-loop feedback approach enables the system to adapt to changing distortion conditions and maintain accurate tracking throughout the medical procedure.
2Measurement precision
If error compensation tools with multiple sensors are added to improve tracking accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The error compensation tool is designed as a multi-functional device that combines electromagnetic sensors, optical tracking sensors, and a processing unit within a single integrated system. The electromagnetic sensors detect field distortions, the optical sensors provide positional reference, and the processor performs both distortion analysis and correction calculations. This universal design allows one device to perform multiple functions, reducing the need for separate components and minimizing overall system complexity while maintaining high tracking accuracy.
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 approach enhances the accuracy and reliability of electromagnetic tracking systems, enabling effective tracking of medical devices in environments with metal distortions, such as cardiac and vascular applications, and reduces the impact of table and field generator movements on tracking precision.
Implementation Method 1
Electrical current is induced in the sensor coil which is a function of the position and orientation of the sensor coil relative to the electromagnetic field generator
Implementation Method 2
an optical tracking sensor attached to the error compensation tool for position and orientation data
Data Source
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AI summary
A system for local metal distortion correction for using an accurate electromagnetic tracking system in a medical environment is disclosed containing an electromagnetic field generator monitoring a medical device having a suitable sensor coil wherein a correction function, derived from an error correction tool, is applied to the position and orientation readings of the sensor coil. The error correction tool consists of a number of electromagnetic sensors arranged in a fixed and known geometric configuration and is placed surrounding the site of the medical procedure. Sensor data is displayed on an imaging system. In addition, a distortion mapping can be done utilizing optical sensors for relative positioning readings along with an electromagnetic tracking system sensor.