全开放式单边核磁共振技术研究及系统开发

摘要

The goal of the study is to design and construct a system that can be used to detect magnetic resonance signals generated in the stray magnetic field produced by fully-opened unilateral magnets. The radiofrequency (RF) probe was carefully designed to meet the detection depth requirement for specific applications, and tested on a unilateral nuclear magnetic resonance experiment system. The probe had a 90º pulse width as short as 2.5 s. The whole system has a short system dead time (i.e., 10 s), and the minimum half echo time was 15 s. The SGSE-CPMG experiment was performed on the system to acquire signals from a depth of 5 mm under a constant B0 gradient of 15.3 T/m. Diffusion coefficients were measured under the constant B0 gradient.%为了在单边磁体产生的逸散磁场中实现核磁共振技术，信号检测深度能满足相关应用需求，该文分析了非均匀磁场下的核磁共振技术条件，确定射频场目标，设计了单边平面射频线圈和探头，搭建出一套单边核磁共振实验系统．探头具有短脉宽(90°脉宽2.5μs)，系统死时间短(10μs)的特点，可实现15μs的半回波时间．应用该系统，在15.3 T/m的巨大梯度磁场下，实现接近5 mm厚度的信号检测，并利用单边磁体的自然梯度磁场，开展了恒定梯度磁场下的扩散测量方法探索．结果表明，该系统可满足需要一定探测深度的领域的应用需求．