宽频磁共振微线圈设计

doi:10.11938/cjmr20253148

摘要/Abstract

摘要：

微量样品检测在环境监测、生物科学和医学等领域具有广泛的应用需求．使用常规磁共振探头对微量样品进行检测时，由于线圈的填充因子较小，导致磁共振检测信噪比降低.采用与微量样品尺寸相当的微线圈进行检测可显著提高探测灵敏度，增强信噪比.此外，由于磁共振宽频探测的需求不断增长，人们希望在样品检测过程中减少实验步骤以缩短检测时间.因此，设计能够覆盖更宽频率范围的磁共振微型线圈变得至关重要.目前市场上的商用宽频探头并非针对微量样品检测而设计，且均为调谐探头，探头电路较为复杂，难以满足高效、便捷的应用需求.针对以上问题，本研究设计了一个多层板螺线管结构微线圈，其射频场均匀性良好，且电感和电阻均较小.利用有限元分析软件对线圈结构进行了优化，并采用印刷电路板（Printed Circuit Board，PCB）技术研制.在1.5 T磁共振成像系统磁体下，利用自研的谱仪及宽频射频前端，对250 nL的不同样品进行了测试，实现了氢核（¹H）、氘核（²H）、锂核（⁷Li）和氟核（¹⁹F）等多种元素的磁共振探测.实验结果证明该线圈具有良好的宽频性能.

关键词: 核磁共振, 微线圈, 宽频, 印刷电路板

Abstract:

The detection of microsamples holds extensive application demands in fields such as environmental monitoring, biological sciences, and medicine. When conventional magnetic resonance probes are used to detect microsamples, the smaller filling factors lead to reduced signal-to-noise ratios (SNR) in magnetic resonance detection. Using microcoils comparable in size to the microsamples can significantly improve detection sensitivity and enhance SNR. Furthermore, due to the growing demand for broadband detection, there is a desire to reduce experimental steps during sample analysis and shorten detection times. However, currently available commercial probes are not designed for microsample detection and are relatively too complex to meet the requirements for efficient and convenient applications. To address these issues, this study designed a multilayer solenoid microcoil with excellent field uniformity, low inductance, and resistance. The coil was fabricated using printed circuit board (PCB) technology and tested on a 1.5 T MRI system magnet equipped with a self-developed spectrometer and broadband RF front end, where multiple nuclei (¹H, ²H, ⁷Li, ¹⁹F) were detected in 250 nL samples, demonstrating broadband capability and high sensitivity. The results highlight its potential for efficient and versatile microsample analysis.

Key words: nclear magnetic resonance (NMR), microcoil, broadband, printed circuit board (PCB)

中图分类号:

O482.53

江超超, 姚守权, 徐俊成, 蒋瑜. 宽频磁共振微线圈设计[J]. 波谱学杂志, 2025, 42(3): 299-307.

JIANG Chaochao, YAO Shouquan, XU Juncheng, JIANG Yu. Design of the Broadband Magnetic Resonance Microcoil[J]. Chinese Journal of Magnetic Resonance, 2025, 42(3): 299-307.

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参数名称	参数设置
原子核	²H	⁷Li	¹⁹F	¹H
样品	99%重水	11.5%六氟磷酸锂溶液	99. 04%六氟苯溶液	4%硫酸铜溶液
中心频率	9.80 MHz	24.52 MHz	60.10 MHz	63.88 MHz
接收带宽	100 kHz	100 kHz	50 kHz	250 kHz
射频脉宽	45 μs	28 μs	15 μs	15 μs
发射功率	30%	20%	16%	14.5%
累加次数	100	500	50	50