Abstract：
A direct comparison of the impact of RF coil design under specific absorption rate andB1+rmslimitations are investigated and quantified using RF coils of different geometries and topologies at 64 MHz and 128 MHz. The RF-inducedin vivoelectric field and power deposition of a 50 cm long pacemaker and 55 cm long deep brain stimulator (DBS) are evaluated within two anatomical models exposed with these RF coils. The associated uncertainty is quantified and analyzed under a fixedB1+rmsincident and normal operating mode. For a fixedB1+rmsincident, thein vivoincident field shows a much higher uncertainty (>5.6 dB) to the RF coil diameter compared to other design parameters (e.g. <2.2 dB for coil length and topology), while the associated uncertainty reduced greatly (e.g. <1.5 dB) under normal operating mode exposure. Similar uncertainties are observed in the power deposition near the pacemaker and DBS electrode. Compared to the normal operating mode, applying a fixedB1+rmsfield to the untested implant will lead to a large variation in the induced incident and power deposition of the implant, as a result, a larger safe margin when different coil designs (e.g. coil diameter) are considered.
摘要：
使用64MHz和128MHz的不同几何形状和拓扑的RF线圈，对SAR和B1均方根限制下RF线圈设计的影响进行了研究和量化。在暴露于这些RF线圈的两个解剖模型中，评估了50厘米长的起搏器和55厘米长的深脑刺激器（DBS）的RF诱导的体内电场和功率沉积。在固定的B1+均方根事件和正常操作模式下对相关的不确定性进行量化和分析。对于固定的B1+rms事件，与其他设计参数相比，体内入射场对RF线圈直径显示出更高的不确定性(>5.6dB)(例如，线圈长度和拓扑结构<2.2dB)，而相关的不确定性大大降低(例如，<1.5dB)在正常工作模式下曝光。在起搏器和DBS电极附近的功率沉积中观察到类似的不确定性。与正常运行模式相比，将固定的B1+rms场应用于未测试的植入物将导致植入物的诱导入射和功率沉积的大变化，因此,当不同的线圈设计时(例如，线圈直径)被考虑。
