Influence of Implantation Depth of Semi-Implantable Devices in Different Tissues on Radio-frequency Heating

In MRI, the implantable or semi-implantable medical devices can have safety implications for the wearer. For semi-implantable medical devices, the depth of implantation and the electrical conductivity of the medium can influence the distribution of radio-frequency (RF) electric fields. Therefore, an analysis of RF heating for devices with different implantation depths in different media is required. This study begins with the principles of RF heating in MRI, establishes models for RF coils, body phantoms, and standard active implantable device, and employs electromagnetic field simulation methods to investigate the RF heating of devices in terms of both implantation depth and medium conductivity. The results indicate that greater implantation depth and higher medium conductivity lead to lower RF heating temperature rises.