Propulsive Coils for MRI-Guided Nanoparticle Therapy
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Solution Overview
Problem
Conventional methods fail to effectively manipulate Magnetic NanoParticles (MNPs) within an MRI system due to interference from the static magnetic field and nerve stimulation caused by induced magnetic fields, limiting the ability to visualize and deliver MNPs to specific locations in the body.
Innovation Solution
The use of propulsive coils generating pulsed magnetic gradients that are interleaved with or separate from the MRI system's imaging gradients, allowing for the propulsion and stabilization of MNPs without interfering with the imaging process, and employing high-magnitude, short-rise-time magnetic fields to increase magnetization and avoid nerve stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional methods use static magnetic fields to manipulate MNPs, then MNPs can be magnetized, but nerve stimulation is caused and MRI image quality deteriorates
Solution Approach 1:
The patent applies periodic pulsed magnetic gradients instead of continuous static fields. The propulsive coils generate time-varying magnetic gradients that are pulsed at specific intervals, creating magnetic forces on MNPs only during the pulse duration. This periodic action achieves the necessary magnetic manipulation while limiting cumulative nerve stimulation and preventing MRI image quality deterioration that would result from continuous field application.
Solution Approach 2:
The system transitions from static magnetic fields to dynamic, time-varying magnetic gradients. The propulsive coils generate magnetic fields that change rapidly in magnitude and direction according to controlled pulse sequences. This dynamic approach allows precise temporal control of magnetic forces on MNPs while avoiding the harmful effects of sustained static fields, including nerve stimulation and MRI interference.
2Force
If high-magnitude magnetic fields are applied to increase magnetization of MNPs, then manipulation effectiveness improves, but nerve stimulation increases
Solution Approach 1:
The patent employs short-duration, high-magnitude magnetic field pulses that rapidly achieve the necessary magnetization of MNPs and then immediately terminate. By rushing through the magnetization process in brief pulses rather than applying sustained fields, the system achieves effective MNP manipulation while minimizing the temporal exposure that would cause nerve stimulation. The quick rise and fall of the magnetic gradients ensures high force generation without prolonged harmful effects.
3Adaptability or versatility
If propulsive coils are added to generate magnetic gradients, then MNP manipulation capability is achieved, but device complexity increases
Solution Approach 1:
The propulsive coils are designed to serve multiple functions: they generate magnetic gradients for MNP propulsion, provide magnetic resonance imaging capability, and enable both imaging and therapy functions within a single integrated system. This multi-functionality reduces overall device complexity by consolidating what would otherwise require separate systems into a unified apparatus that performs both diagnostic and therapeutic roles.
Solution Approach 2:
The patent merges the MNP propulsion function with the MRI imaging system by integrating propulsive coils that can generate both the magnetic gradients needed for imaging and the additional gradients required for MNP manipulation. This combination allows the system to perform dual functions—imaging and targeted MNP delivery—without requiring completely separate apparatus, thereby managing complexity through functional integration.
4Manufacturing precision
If pulsed magnetic gradients are used for MNP propulsion, then precise MNP delivery is achieved, but interference with MRI imaging may occur
Solution Approach 1:
The system uses periodic pulsed magnetic gradients with carefully controlled timing and duty cycles. The pulses are applied in intermittent sequences rather than continuously, allowing periods during which imaging can proceed without interference. This periodic modulation enables precise MNP delivery during pulse phases while maintaining MRI image quality during inter-pulse phases, resolving the contradiction between propulsion precision and imaging reliability.
Solution Approach 2:
The magnetic gradient fields are dynamically modulated in time, switching between propulsion phases and imaging phases. During propulsion phases, high-magnitude gradients are applied to manipulate MNPs with precision; during imaging phases, the gradients are reduced or switched off to allow clean MRI signal acquisition. This dynamic temporal separation allows both functions to operate at optimal performance without mutual interference.
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 manipulation and visualization of MNPs under MRI guidance, overcoming the limitations of conventional methods by achieving higher magnetic gradient strengths and improved spatial resolution without reducing the quality of MRI images.
Implementation Method 1
The propulsive coils may be inserted into an MRI scanning system and used in conjunction with one or more electrical current generators to create pulsed magnetic gradients that deliver the MNPs to desired locations in the body.
Implementation Method 2
Disclosed embodiments provide a method and apparatus for manipulating Magnetic NanoParticles (MNPs) in the body, for example, under imaging guidance.
Data Source
AI summary
An apparatus and method direct nanoparticles in a body part under imaging guidance using at least one electromagnet configured and operable to create a magnetic field gradient used to direct the nanoparticles, wherein, the magnetic field gradient used to direct the nano-particles does not substantially interfere with the use of magnetic field gradients whose purpose is to image the body part.