北京生物医学工程

一种基于光抽运效应的磁共振信号检测方法

A Novel MR Signal Detection Method Based on Optical Pumping

作者：王慧贤赵武贻杨文晖胡丽丽王铮

单位：中国科学院电工研究所(北京100190)

分类号：

出版年·卷·期（页码）：2010·29·4（349-352）

摘要：

与常规磁共振成像相比，超低场磁共振成像技术所需的成像磁体可降至mT级甚至μT级，不仅大大降低了设备的成本和体积，还能够获得普通高场磁共振成像设备无法得到的特殊图像，具有非常广阔的应用前景。本文介绍了一种基于光抽运现象的磁共振信号检测方法，该方法根据外加磁场会影响碱金属原子对特定波长光吸收的原理，通过检测透射光强的变化检测磁共振信号。文章最后利用线圈产生模拟磁共振信号，给出了一维及二维磁共振成像的实验结果，结果表明该方法对于磁共振信号有良好的频率分辨率及相位控制的稳定性。由于该方法具有高灵敏度、低成本以及在信号检测时需要很弱背景场等特点，因此特别适用于超低场磁共振信号的检测。

Compared with conventional magnetic resonance imaging (MRI) system，the main magnetic field of ultralow field MRI system could be reduced to mT level or even μT level，which not only reduces the cost and size of the equipment, but also makes it possible to obtain special images which would be impossibly obtained by ordinary high field MRI equipments. The paper proposes a new magnetic resonance signals detection method based on optical pumping, which uses the principles that an external magnetic field affects the alkali metal atoms on the absorption of specific wavelengths of light, and magnetic resonance signals can be measured by detecting the transmitted light intensity. Finally, the paper presents the experiment results of simulated one dimensional and two dimensional MRI signals generated via a coil. The results show that the method has a good frequency resolution and stability of phase control for magnetic resonance signals detection. Since the method has high sensitivity, low cost and the need for very weak background field in signal detection, it is especially suitable for ultralow field magnetic resonance signal detection.

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