Magnetic Particle Imaging Coil Layout for FFL Alignment
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Solution Overview
Problem
The sensitivity center of the measurement coil and the linear position of the near field-free region (FFL) in magnetic particle imaging devices cannot be easily aligned, leading to reduced detection accuracy due to mismatched positions.
Innovation Solution
A magnetic particle imaging device with a pair of alternate-current magnetic field application coils, a direct-current magnetic field applicator, and a magnetism change measurement device, including pairs of first and second measurement coils, is designed to determine the sensitivity center and FFL position mechanically, using a measurement device to output a signal difference between the coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only a single measurement coil is used, then the device structure is simple, but the sensitivity center cannot be aligned with the linear near field-free region position
Solution Approach 1:
The measurement system is divided into multiple measurement coils (first measurement coils and second measurement coils) arranged in pairs. Each pair is positioned at different locations relative to the magnetic particles, allowing the sensitivity center to be mechanically aligned with the linear near field-free region position through proper spatial arrangement of the segmented coil system.
2Measurement precision
If multiple measurement coils are added to enable mechanical alignment, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
Multiple measurement coils are merged into a coordinated system where the first measurement coils and second measurement coils work together. The signals from these coils are processed in combination, with the measurement device outputting a signal representing the difference between signals measured by the coil pairs, achieving both mechanical alignment capability and improved detection accuracy.
Solution Approach 2:
The multiple measurement coils serve multiple functions: they enable mechanical alignment of the sensitivity center with the linear near field-free region, provide redundant measurement capability, and allow for differential signal processing to enhance detection accuracy while maintaining a relatively compact device structure.
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 allows for precise alignment of the sensitivity center and FFL position, enhancing detection accuracy and reducing noise interference.
Implementation Method 1
a pair of alternate-current magnetic field application coils to excite an alternate-current magnetic field
Implementation Method 2
a direct-current magnetic field applicator to generate a linear near field-free region such that magnetism of magnetic particles included in a test object is changed
Implementation Method 3
a magnetism change measurement device to measure a magnetism change in the magnetic particles
Data Source
AI summary
A pair of first measurement coils is disposed so as to sandwich magnetic particles. A pair of second measurement coils is disposed so as to sandwich magnetic particles and the pair of first measurement coils. A pair of alternate-current magnetic field application coils is disposed so as to sandwich magnetic particles, the pair of first measurement coils, and the pair of second measurement coils. A measurement device outputs a signal representing a difference between a signal measured by the pair of first measurement coils and a signal measured by the pair of second measurement coils.