永磁微型磁共振成像仪的射频线圈及鼠成像实验

Development of RF Coil of Permanent Magnet Mini-magnetic Resonance Imager and Mouse Imaging Experiments

研发高质量的射频线圈,以提高永磁微型小动物用磁共振成像仪的成像质量。在分析各类线圈的基础上,认为对于永磁系统中的螺线管型线圈有独到的优越性,但直接应用不能满足成像需要。通过理论分析螺线管射频线圈磁场的特点,确定了进一步提高线圈磁场的均匀性、提高接收信号的灵敏度和信噪比为研究方向。借鉴了鸟笼型、马鞍型和相控阵线圈的优势,避开它们的不足,使用自己专利技术的合金材料设计并制作出适用于永磁微型磁共振成像仪的龙骨状、多线圈组合型、单通道整体射频接收线圈,并申请了专利。安装于25mm孔径,主磁场强度0.5T、1.5T,以及50mm孔径,主磁场强度0.48T的三种仪器上,进行小鼠、大鼠和荷瘤裸小鼠实验,结果表明该射频接收线圈完全适用于永磁型成像系统。

In the development of radio frequency（RF）coils for better quality of the mini-type permanent magnetic resonance imager for using in the small animal imaging,the solenoid RF coil has a special advantage for permanent magnetic system based on analyses of various types of RF coils.However,it is not satisfied for imaging if the RF coils are directly used.By theoretical analyses of the magnetic field properties produced from the solenoid coil,the research direction was determined by careful studies to raise further the uniformity of the magnetic field coil,receiving coil sensitivity for signals and signal-to-noise ratio（SNR）.The method had certain advantages and avoided some shortcomings of the other different coil types,such as,birdcage coil,saddle shaped coil and phased array coil by using the alloy materials（from our own patent）.The RF coils were designed,developed and made for keeled applicable to permanent magnet-type magnetic resonance imager,multi-coil combination-type,single-channel overall RF receiving coil,and applied for a patent.Mounted on three instruments（25mm aperture,with main magnetic field strength of 0.5Tor 1.5T,and 50 mm aperture,with main magnetic field strength of 0.48T）,we performed experiments with mice,rats,and nude mice bearing tumors.The experimental results indicated that the RF receiving coil was fully applicable to the permanent magnet-type imaging system.