面向乳腺肿瘤床旁检测的浅表器官小型磁共振成像系统关键技术研究

针对乳腺肿瘤检测的需求，突破浅表器官磁共振成像系统小型化的瓶颈，开展乳腺肿瘤床旁检测小型磁共振系统关键技术的研究，具体涉及以下几方面的研究：（1）设计一种单边Halbach阵列磁体结构，结合无源匀场方法，优化水平磁场均匀性和竖直磁场梯度的线性度；（2）设计一种非对称梯度线圈结构，提供高线性度的水平脉冲梯度场；（3）设计一种契合乳房器官的半球形成像线圈，结合集成双工器、调谐匹配和放大功能的电路结构，提供高均匀性的射频场和高信噪比的磁共振信号；（4）基于上述硬件的研制，优化空间结构，完成乳腺肿瘤床旁检测小型磁共振装置的搭建；（5）设计适用于单边磁体的成像脉冲序列，优化脉冲参数，提高成像质量；（6）开展乳腺肿瘤成像实验研究，通过计算机辅助与深入学习算法，建立可靠的乳腺肿瘤诊断模型。

For advanced diagnosis of breast cancer, this subject set out to break through the bottleneck of miniaturization of superficial organ magnetic resonance imaging system and realize bedside detection of breast tumor. This study involves the following key aspects: (1) Design a single-sided magnet structure by using halbach arrays with the passive shimming method to realize the high homogeneity of magnetic field in xy-plane and the good linearity of magnetic gradient along z-axis. (2) Design an asymmetric gradient coil structure to supply a higher good linearity of pulsed field gradient in xy-plane. (3) Design a RF coil with a hemispherical structure suitable for the shape of breast organs, and the combined circuit integrates a tuned circuit, a duplexer and a preamplifier to provide high uniformity of rf field and high signal-to-noise ratio magnetic resonance signal. (4) Based on the hardware developed above, consider the compact structure and assemble a small-sized magnetic resonance imaging device for breast tumor detection. (5) Design specific pulse sequences that apply to single-sided magnet structure and breast tumor detection, and optimize parameters to improve the quality of MRI images. (6) Establish a reliable breast tumor diagnosis model after imaging experiments by using computer aided skills and deep learning algorithms.