中文摘要：

对基于高温超导量子干涉仪的低场核磁共振成像进行了较为系统的探索. 首先对低场核磁共振系统进行了改进和完善, 使得装置能够用于成像实验. 在此基础上进行了一维、二维成像实验并取得了成功. 二维成像分别采用了直接背投影成像法和傅里叶变换重建法. 采用直接背投影方法成功获得了不同水样品分布的图形并与实物符合较好, 同时还尝试对生物样品如青椒和芹菜的切片进行了成像, 也得到了符合原物的二维投影像. 尝试用傅里叶变换法对水样品进行成像, 得到的图形能够显示样品轮廓, 但信噪比偏低. 对两种二维成像方法进行了比较和讨论.

英文摘要：

A systematic research on ultra-low field magnetic resonance imaging （MRI） is conducted based on high-Tc dc-SQUID senor. The coil system is first updated to reach the requirements of MRI experiment. After that one-dimensional and two-dimensional imaging are performed and images consistent well with original phantoms are obtained successfully. Two different methods are used to rebuild the image： direct back projection and Fourier transform reconstruction. Both of them can obtain the profile of water phantom. A comparative discussion between these methods is proposed： the Fourier transform method has a better profile, while the direct back projection has a better signal-to-noise ratio. Imaging of biological sample such as green pepper and celery is also performed, and it is consistent well with the physical object.