Magnetic Particle Imaging Harmonic Signal Distribution
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Solution Overview
Problem
Current Magnetic Particle Imaging (MPI) techniques face limitations in sensitivity and localization accuracy, relying on saturation fields and limited signal-to-noise ratios, which hinders precise imaging and temperature measurement of nanoparticles.
Innovation Solution
The use of combinations of static and oscillating magnetic fields to distribute signals among harmonics, allowing for improved sensitivity, localization, and the elimination of saturation fields, enabling better signal-to-noise ratios and enabling temperature measurement through the spectral distribution of nanoparticle signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If saturation fields are used in MPI, then signal detection is enabled, but sensitivity and localization accuracy are limited
Solution Approach 1:
The patent changes the magnetic field parameters by using oscillating fields at multiple frequencies instead of saturation fields. The nanoparticles respond to these oscillating fields with harmonic signals that can be detected and used for localization, eliminating the need for saturation fields while improving measurement precision.
Solution Approach 2:
The patent applies periodic oscillating magnetic fields at different frequencies to the nanoparticles. The nanoparticles generate harmonic responses at multiples of the driving frequencies, which are detected to determine nanoparticle location and concentration, replacing the saturation field approach with periodic excitation.
2Measurement precision
If limited signal-to-noise ratios are used, then detection is simplified, but imaging resolution and sensitivity are reduced
Solution Approach 1:
By using periodic oscillating fields at known frequencies, the patent generates harmonic signals at predictable frequencies (multiples of the driving frequencies). This allows for frequency-based signal separation and filtering, improving the signal-to-noise ratio while enhancing imaging resolution through spectral analysis.
Solution Approach 2:
The patent uses frequency as an intermediary parameter to separate signals from noise. By detecting signals at specific harmonic frequencies generated by the oscillating fields, the system can filter out noise at other frequencies, improving both signal-to-noise ratio and imaging resolution simultaneously.
3Object-affected harmful factors
If saturation fields are eliminated, then safety and comfort improve, but signal generation capability must be maintained
Solution Approach 1:
The patent uses periodic oscillating magnetic fields at multiple frequencies to generate harmonic signals from nanoparticles. These oscillating fields produce detectable signals without requiring high saturation fields, thereby reducing harmful effects while maintaining sufficient signal generation capability for imaging and temperature measurement.
Solution Approach 2:
The patent transitions from static saturation fields to dynamic oscillating fields. The time-varying nature of the oscillating fields allows the nanoparticles to generate harmonic responses that can be detected, providing signal generation capability without the harmful effects of saturation fields while enabling temperature measurement through spectral analysis.
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 imaging resolution and localization accuracy, allowing for more precise tracking of nanoparticles and temperature measurement, even in varying particle concentrations and sizes, while providing additional diagnostic and therapeutic insights.
Implementation Method 1
distribute signals among harmonics, allowing for improved sensitivity, localization
Implementation Method 2
Magnetic Particle Imaging (MPI), and to using magnetic particles as biomarkers for measuring particle temperature
Implementation Method 3
enabling temperature measurement through the spectral distribution of nanoparticle signals
Implementation Method 4
The MPI system detects particles in the field-free point where there is very little static field. Those particles in the field free point produce signal at the harmonics
Implementation Method 5
In a zone which is denoted by a dashed circle (the first sub-zone) around the field-free point the field strength is so low that the magnetization of magnetic particles present therein is not saturated, whereas the magnetization is in a state of saturation outside the zone
Data Source
AI summary
This invention provides a system and method that improves the sensitivity and localization capabilities of Magnetic Particle Imaging (MPI) by using combinations of time-varying and static magnetic fields. Combinations of magnetic fields can be used to distribute the signals coming from the magnetic particles among the harmonics and other frequencies in specific ways to improve sensitivity and to provide localization information to speed up or improve the signal-to-noise ratio (SNR) of imaging and/or eliminate the need for saturation fields currently used in MPI. In various embodiments, coils can be provided to extend the sub-saturation region in which nanoparticles reside; to provide a static field offset to bring nanoparticles nearer to saturation; to introduce even and odd harmonics that can be observed; and/or to introduce combinations of frequencies for more-defined observation of signals from nanoparticles. Further embodiments provide for reading of the signal produced by cyclically saturated magnetic nanoparticles in a sample so as to provide a measurement of the temperature of those nanoparticles.