IC at Coil Tracking System for MRI RF Heating Reduction
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Solution Overview
Problem
Conventional MRI tracking systems for medical devices in the MRI environment face RF-induced heating risks due to elongated conductive structures, which can cause Ohmic, Joule, and dielectric heating, compromising patient safety and requiring the elimination of transmission lines to minimize heating and signal interference.
Innovation Solution
An IC at Coil tracking system is developed, integrating components like frequency down-converters and analog-to-digital converters at the tracking coil location, using MR-safe conductors or fiber optics to replace transmission lines, and performing signal processing locally to reduce interference and heating risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmission lines are used in MRI tracking systems, then signal transmission capability is improved, but RF-induced heating risk increases
Solution Approach 1:
The patent extracts and removes the transmission line from the MRI tracking system, eliminating the elongated conductive structure that causes RF-induced heating. The tracking coil is directly connected to the receiver without intermediate transmission lines, thereby removing the source of heating while preserving signal transmission capability through direct coupling.
Solution Approach 2:
The patent introduces MR-safe conductors or fiber optics as intermediary elements to replace traditional transmission lines. These intermediaries transmit signals without causing RF-induced heating, as they are either non-conductive (fiber optics) or specifically designed to be MRI-safe with minimal RF interaction.
2Object-affected harmful factors
If transmission lines are eliminated, then RF heating is minimized, but signal transmission distance capability deteriorates
Solution Approach 1:
The patent replaces the mechanical/electrical transmission line system with an optical system (fiber optics) or direct electrical connection. This substitution eliminates RF heating issues while maintaining signal transmission capability through alternative physical mechanisms that do not interact with the MRI RF field.
3Object-generated harmful factors
If signal processing is performed locally at the coil, then interference with MR imaging signals is reduced, but device complexity increases
Solution Approach 1:
The patent merges the signal processing functions (frequency down-conversion, analog-to-digital conversion) directly into the tracking coil assembly. This consolidation performs multiple functions at the coil location, reducing signal interference with MR imaging while integrating complexity into a compact unit rather than distributing it across separate components.
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 significantly minimizes RF heating, enhances patient safety, and decreases the complexity of the tracking receiver by eliminating the need for transmission lines and reducing signal interference with MR imaging signals.
Implementation Method 1
a frequency down-converter configured to down-convert a magnetic resonance (MR) signal received by the tracking coil
Implementation Method 2
The RF field, applied at the resonance frequencies, disturbs the initial alignment, such that when the protons relax back to their initial alignment, the RF emitted from the relaxation event may be detected
Data Source
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AI summary
An active tracking system that overcomes the heating problems of conventional transmission line and signal line conductors is provided. The active tracking system includes at least one active tracking coil; at least one integrated circuit proximate the active tracking coil; a tracking receiver; a first MR safe means configured for transmitting a received signal to the tracking receiver; and a second MR safe means configured for communicating one or more signals from the tracking receiver to the integrated circuit at coil. The integrated circuit may also include frequency estimations, analog to digital conversion at the tracking coil location to reduce the amount of processing required in the tracking receiver thereby decreasing the potential for signals passing from the tracking coil location to the tracking receiver to interfere with MR imaging signals.