Bardwell Speltz Lydia J, Lee Seung-Kyun, Shu Yunhong, Bernstein Matt A
Department of Radiology, Mayo Clinic, Rochester, MN, United States, Mayo Clinic, 200 First St. SW, Rochester, MN 55905.
GE HealthCare Technology & Innovation Center, Niskayuna, NY, United States, 1 Research Circle, Niskayuna, New York 12309.
ArXiv. 2024 Dec 19:arXiv:2412.15120v1.
To theoretically and experimentally study implant lead tip heating caused by radiofrequency (RF) power deposition in different wire configurations that contain loop(s).
Maximum temperature rise caused by RF heating was measured at 1.5T on 20 insulated, capped wires with various loop and straight segment configurations. The experimental results were compared with predictions from the previously reported simple exponential and the adapted transmission line models, as well as with a long-wavelength approximation.
Both models effectively predicted the trends in lead tip temperature rise for all the wire configurations, with the adapted transmission line model showing superior accuracy. For superior/inferior (S/I)-oriented wires, increasing the number of loops decreased the overall heating. However, when wires were oriented right/left (R/L) where the -component of the electric field is negligible, additional loops increased the overall heating.
The simple exponential and the adapted transmission line models previously developed for, and tested on, straight wires require no additional terms or further modification to account for RF heating in a variety of loop configurations. These results extend the models' usefulness to manage implanted device lead tip heating and provide theoretical insight regarding the role of loops and electrical lengths in managing RF safety of implanted devices.
从理论和实验两方面研究在含有环的不同导线配置中，射频（RF）功率沉积所导致的植入式导线尖端发热情况。
在1.5T磁场下，对20根具有各种环和直线段配置的绝缘、带帽导线测量由射频加热引起的最大温度升高。将实验结果与先前报道的简单指数模型、改进的传输线模型以及长波长近似模型的预测结果进行比较。
两种模型都有效地预测了所有导线配置下导线尖端温度升高的趋势，其中改进的传输线模型显示出更高的准确性。对于上下（S/I）取向的导线，增加环的数量会降低整体发热。然而，当导线为左右（R/L）取向时，电场的 - 分量可忽略不计，额外的环会增加整体发热。
先前为直线导线开发并测试的简单指数模型和改进的传输线模型，无需额外项或进一步修改即可用于解释各种环配置中的射频加热情况。这些结果扩展了模型在管理植入式设备导线尖端发热方面的实用性，并为环和电气长度在管理植入式设备射频安全性中的作用提供了理论见解。
