2种电磁屏蔽材料在3.0T磁共振成像系统的应用探讨

Application Study of Two Electromagnetism Shielding Materials in 3.0T Magnetic Resonance Imaging System

目的：探讨紫铜板和冷扎镀锌钢板在3.0T磁共振成像系统中作为电磁屏蔽材料的应用效果。方法：飞利浦Achiva 3.0T磁共振成像系统在电磁屏蔽工程中使用的材料是0.5 mm的紫铜板（非磁性材料）,西门子Verio3.0T磁共振成像系统在电磁屏蔽工程中使用的材料是3.0 mm的冷轧镀锌钢板（软磁材料）。结果：主磁体吊装进入扫描室后,把屏蔽体缺口封闭好,在励磁之前进行电磁屏蔽工程屏蔽效能的检测。紫铜板屏蔽室各特定检测点及特定检测频率的屏蔽效能为100~106 dB,均值为（102±2）dB;冷扎镀锌钢板屏蔽室各特定检测点及特定检测频率的屏蔽效能为101~106 dB,均值为（103±1）dB,二者之间的差异无统计学意义（P〉0.05）。但紫铜板屏蔽室有磁力线穿透至外墙,六面体封闭结构不如冷轧镀锌钢板坚固。结论：紫铜板与冷扎镀锌钢板这2种屏蔽材料对电磁波的屏蔽效能无明显差异,但紫铜板屏蔽室有磁力线穿透至外墙。

Objective To approach the application of red copper coin and cold-rolled galvanized steel as the electromagnetic shielding materials in 3.0T magnetic resonance imaging system.Methods Phillips Achiva 3.0T magnetic resonance imaging system used red copper coin,a kind of nonmagnetic material,as the shielding material,and Siemens Verio 3.0T magnetic resonance imaging system employed cold-rolled galvanized steel,a kind of soft magnetic material,as the shielding material.After the main magnet was hoisted into the scanning room,the nick of shielding was closed.The shielding effectiveness was detected before excitation.Results The measurement was 100 dB to 106 dB for the red copper coin with a mean value of（102±2）dB and 101 dB to 106 dB for the cold-rolled galvanized steel with a mean value of（103±1）dB.There was no significant difference between the performances of the two materials with P0.05,while magnetic lines might penetrate the red copper coin and the closed hexahedron structure behaved not so good as that of cold-rolled galvanized steel.Conclusion There is no significant between the shielding effectiveness of the two materials,while red copper shielding room may have some magnetic lines fleeing to the external wall.