RF Pilot Tone Positioning for MRI Therapeutic Devices
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Solution Overview
Problem
Current MRI systems face challenges in accurately and efficiently locating therapeutic devices within the body during interventional procedures without altering MRI imaging sequences or requiring expensive active tracking systems, especially when devices are outside the imaging plane.
Innovation Solution
A method using a radio frequency pilot tone signal that is radiated into the body and received by spatially distributed MRI receiver coils to determine the position of objects, such as therapeutic devices, without needing special MRI tracking sequences, allowing for continuous location and alignment during MRI recording, and utilizing normalization and calibration techniques to improve positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If passive tracking methods using magnetic susceptibility properties are used to make devices visible on MRI images, then device visibility is improved, but manual identification and tracking becomes very difficult when the device is situated outside the imaging plane
Solution Approach 1:
The patent introduces a pilot tone signal as an intermediary that modulates the MRI signal in response to device position. This mediator enables automatic tracking by providing a detectable signal that correlates with device location, eliminating the need for difficult manual identification while maintaining device visibility.
Solution Approach 2:
The patent replaces the manual mechanical tracking process with an automated signal processing system. By substituting the manual identification and tracking operation with an automated algorithm that processes pilot tone modulated signals, the system achieves continuous tracking without operator intervention.
2Reliability
If active tracking methods with MRI microreceiver coils are used to enable continuous position tracking, then tracking capability is improved, but device cost and size increase significantly
Solution Approach 1:
The patent makes the therapeutic device multi-functional by enabling it to both deliver therapy and serve as a passive sensor for position tracking. The device structure itself interacts with the pilot tone signal, allowing a single device to perform multiple functions without requiring separate active tracking components.
Solution Approach 2:
The therapeutic device serves itself for tracking purposes by utilizing its own structural properties to modulate the pilot tone signal. The device does not require separate active tracking components because its presence and position naturally affect the electromagnetic field, enabling self-tracking capability.
3Measurement precision
If special MRI tracking sequences are activated for active device tracking, then position determination accuracy is improved, but the tracking is restricted and not available in every anatomical imaging sequence
Solution Approach 1:
The patent employs periodic pilot tone signals that are continuously transmitted throughout the imaging process. This periodic action allows position information to be extracted from standard anatomical imaging sequences without requiring special tracking sequences, making tracking available across all imaging modes.
Solution Approach 2:
The patent merges the position tracking function with standard anatomical imaging by superimposing the pilot tone signal on the imaging sequence. This combination allows both anatomical visualization and device tracking to occur simultaneously using the same imaging sequence, eliminating the need for separate tracking sequences.
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 precise and continuous location of therapeutic devices within the body without modifying MRI imaging sequences, allowing for accurate tracking and alignment, even when devices are outside the imaging plane, and simplifies the navigation function for MRI imaging positions.
Implementation Method 1
a radio frequency signal ('RF pilot tone') is generated and radiated into the body, b) a response signal modulated by the radiating into the body is received
Data Source
AI summary
Systems and Methods for determining a position of an object introduced into a body. An RF pilot tone is generated and is radiated into the body. Response signals modulated by the radiating into the body are received by a plurality of MRI receiver coils arranged spatially distributed outside the body and are converted into respective measurement signals. From the measurement signals, the position of the object is determined.