Fluorolucent Planar Coil Layout for Distortion-Resistant Tracking
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Solution Overview
Problem
Magnetic field generators used in medical positioning systems face distortions due to nearby objects, such as x-ray sources and c-arms, which can lead to inaccurate tracking of medical devices like catheters during procedures, especially when these objects move, causing unpredictable eddy currents and impedance distortions.
Innovation Solution
A fluorolucent magnetic transmitting element is designed to minimize interference by being placed closer to the navigational domain, using planar coils made from materials like aluminum that are translucent in fluoroscopy images, reducing heat dissipation and allowing for a more concentrated magnetic field with reduced visibility in fluoroscopic images, and employing a drive circuit with a Howland current source and phase lead capacitor to efficiently generate and control the magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic field generators are used, then magnetic field generation is achieved, but magnetic field distortions occur due to nearby objects like x-ray sources and c-arms
Solution Approach 1:
The patent extracts the magnetic field generating function from conventional coil structures and implements it through fluorolucent planar elements that can be positioned closer to the navigational domain. This separation allows the magnetic field generation to occur without the interference of traditional generator components, eliminating distortions caused by nearby objects while maintaining field accuracy for tracking medical devices
Solution Approach 2:
The patent introduces fluorolucent planar elements as intermediary components between the magnetic field source and the navigational domain. These elements serve as a mediator that generates the required magnetic field while being transparent to fluoroscopic imaging, thereby preventing distortion of both the magnetic field and the visual field during medical procedures
2Temperature
If planar coils made from aluminum are used, then heat dissipation is reduced and magnetic field concentration is improved, but visibility in fluoroscopic images decreases
Solution Approach 1:
The patent applies the principle of optical property modification by using aluminum-based fluorolucent materials that have specific radiographic characteristics. These materials are designed to be translucent in fluoroscopy, allowing the magnetic field generating elements to be positioned closer to the area of interest without obscuring the fluoroscopic view, while simultaneously improving heat dissipation properties
3Measurement precision
If magnetic field generators are placed closer to the navigational domain, then tracking accuracy is improved, but interference from nearby objects increases
Solution Approach 1:
The patent extracts the magnetic field generating function from conventional bulky generators and implements it through thin, fluorolucent planar elements. This extraction allows the field-generating components to be positioned immediately adjacent to the navigational domain without introducing additional interfering objects, as the elements themselves are radiographically translucent and do not create eddy currents or impedance distortions
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 solution reduces magnetic field distortions, allowing for more accurate tracking of medical devices with reduced interference from nearby objects, enhancing the precision of medical procedures while maintaining clear fluoroscopic images and efficient heat management.
Implementation Method 1
A fluorolucent magnetic transmitting element for generating a magnetic field for tracking of an object
Implementation Method 2
employing a drive circuit with a Howland current source and phase lead capacitor to efficiently generate and control the magnetic field
Data Source
AI summary
A transmitting element for generating a magnetic field for tracking of an object includes a first spiral trace that extends from a first outer origin inward to a central origin in a first direction. A second spiral trace can extend from the central origin outward to a second outer origin in the first direction. The second spiral trace can extend from the central origin to the second outer origin in the first direction. The first spiral trace and the second spiral trace can be physically connected at the central origin to form the fluorolucent magnetic transmitting element and at least a portion of the first spiral trace overlaps at least a portion of the second spiral trace.