School of Information Engineering, Nanchang University, People's Republic of China.
School of Information Science and Engineering, Lanzhou University, People's Republic of China.
Phys Med Biol. 2024 Feb 26;69(5). doi: 10.1088/1361-6560/ad2714.
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-inducedelectric 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, theincident 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.
在特定吸收率和 B1+rms 限制下，研究并量化了不同几何形状和拓扑结构的 RF 线圈的影响。在 64 MHz 和 128 MHz 下，使用这些 RF 线圈评估了 50 厘米长的起搏器和 55 厘米长的深部脑刺激器 (DBS) 在两个解剖模型中的 RF 感应电场和功率沉积。在固定的 B1+rms 入射和正常工作模式下，对相关不确定性进行了量化和分析。对于固定的 B1+rms 入射，入射场的不确定性比其他设计参数（例如线圈长度和拓扑结构的 <2.2 dB）对 RF 线圈直径的不确定性要高得多（例如 >5.6 dB），而在正常工作模式下，不确定性大大降低（例如 <1.5 dB）。在起搏器和 DBS 电极附近的功率沉积中也观察到类似的不确定性。与正常工作模式相比，将固定的 B1+rms 场施加到未经测试的植入物上会导致植入物的感应入射和功率沉积发生很大变化，因此，在考虑不同的线圈设计（例如线圈直径）时，需要更大的安全裕度。
