射频接收线圈是磁共振成像系统输入通道的第一级,提高接收线圈的信噪比可以提高系统的图像质量.对于低场磁共振成像系统,如果能够降低常规铜接收线圈的等效串联电阻,就能够提高其信噪比.由于高温超导材料的直流电阻为零,交流传输损耗也远小于铜,采用高温超导材料制作磁共振接收线圈能够提高信噪比.本文采用Bi2223带材,设计、制作了超导接收线圈,并在0.23T的磁共振成像系统中进行了成像实验.结果表明,超导接收线圈的图像信噪比比常规铜线圈提高约76%.
RF receiving Coil is the first hard device in the signal input channel of MRI. Improving the signal noise ratio (SNR) of the RF receiving coil can improve the image quality. For the low field MRI system, SNR is inversely dependent on the resistance of the copper resonance coil, lower the copper resistance can increase the SNR. Since High-Temperature Superconductor (HTS) has zero DC resistance and very low AC losses, replacing the copper material by the HTS can increase the SNR of the RF receiving coil. A Bi2223 tape High-Temperature Superconducting RF receiving Coil has been designed and constructed in this paper. The coil was then tested in a 0.23T MRI system. The image results show that the SNR of HTS RF coils has improved 76%.