Magnetic Particle Imaging Detection Coil Resonance Tuning
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Solution Overview
Problem
Existing magnetic particle imaging devices face challenges in detecting signals associated with changes in magnetization of magnetic particles with high sensitivity, especially when the amount of magnetic particles in an inspection object becomes extremely small.
Innovation Solution
A magnetic particle imaging device is designed with a detection coil having an axis parallel to the AC magnetic field, a measuring instrument connected to the detection coil, and a resonance frequency variable device including a capacitor to adjust the resonance frequency of the detection coil and measuring instrument. The capacitor is adjusted to match the resonance frequency with the frequency of the harmonic signal emitted by the magnetic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synchronous detection of odd-order harmonic is used to detect magnetic particle signals, then measurement precision is improved, but detection sensitivity becomes insufficient when magnetic particle amount is extremely small
Solution Approach 1:
The patent applies resonance frequency adjustment to the detection coil circuit, causing it to vibrate at the same frequency as the harmonic signal from magnetic particles. This resonant vibration amplifies the weak signals from small amounts of magnetic particles, enabling reliable detection even when particle amounts are extremely small.
Solution Approach 2:
The patent changes the resonance frequency parameter of the detection coil circuit by adjusting capacitance values. This parameter adjustment allows the detection system to match the frequency of the harmonic signal from magnetic particles, thereby improving detection sensitivity and enabling reliable measurement of small particle amounts.
2Measurement precision
If the amount of magnetic particles in inspection object is reduced, then imaging resolution is improved, but signal intensity becomes too weak for reliable detection
Solution Approach 1:
By adjusting the resonance frequency of the detection coil to match the harmonic signal frequency from magnetic particles, the system amplifies weak signals through resonant vibration. This enables reliable detection of signal intensity even when the amount of magnetic particles is reduced for high-resolution imaging.
Solution Approach 2:
The detection coil acts as an intermediary that transfers and amplifies the weak magnetic signals from small amounts of magnetic particles. By tuning the detection coil's resonance frequency to match the signal frequency, it mediates between the weak particle signals and the measurement system, preserving signal intensity for reliable detection.
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 configuration enables the detection of signals associated with changes in magnetization of magnetic particles with high sensitivity, even when the amount of magnetic particles is extremely small, by maximizing the signal intensity of the targeted harmonic signal.
Implementation Method 1
The change in the magnetic flux interlinking the detection coil can be detected as a change in an induced electromotive force generated in the detection coil
Implementation Method 2
a resonance frequency variable device including a capacitor connected in parallel to the detection coil in order to adjust a resonance frequency of the detection coil and the measuring instrument. A capacity of the capacitor is adjusted such that a resonance frequency of a closed circuit including the detection coil, the measuring instrument, and the resonance frequency variable device coincides with a frequency of the harmonic signal
Data Source
AI summary
A static magnetic field generator generates a non-magnetic field region. An AC magnetic field application instrument applies an AC magnetic field to the non-magnetic field region. A detection coil has an axis parallel to a direction of the AC magnetic field in order to detect a magnetization signal. A measuring instrument is connected to the detection coil. A resonance frequency variable device includes a capacitor connected in parallel to the detection coil in order to adjust a resonance frequency of the detection coil and the measuring instrument. A capacity of the capacitor is adjusted such that a resonance frequency of a closed circuit including the detection coil, the measuring instrument, and the resonance frequency variable device including the capacitor coincides with a frequency of a harmonic signal.