磁共振成像超导接收线圈品质因数的实验研究

Experimental Study on Quality Factor of Superconducting Receiving Coil for MRI

射频接收线圈是磁共振成像系统中的重要部件,主要针对超导接收线圈的品质因数进行实验研究,并给出了测试原理和方法。使用一种双探测线圈法对Bi2223/Ag超导带材制作的接收线圈在室温和液氮温度下的品质因数进行了测试,并与铜制谐振回路的测试结果进行对比分析。结果表明,在77K下超导接收线圈比室温下铜线圈的品质因数高约两倍。这说明使用超导材料制作射频接收线圈,可有效提高谐振回路的品质因数,从而进一步改善磁共振成像系统的信噪比及成像质量。

The radio frequency （RF） receiving coil is an important element in magnetic resonance imaging（MRI） system. The quality factor （Q） of superconducting receiving coil was studied experimentally, and the testing principle and method were presented in this paper. A kind of double detecting coil method was used to measure the quality factor of superconducting receiving coil made of Bi2223/Ag tape at room temperature and liquid nitrogen temperature. These testing results were contrasted with those of Cu resonance loop. The results show that the quality factor of superconducting receiving coil is double bigger than that of normal copper coil at room temperature. This indicates that using superconducting material as the RF receiving coil can efficiently enhance the quality factor of resonance loop, and accordingly improve the signal noise ratio （SNR） and image quality of MRI system.