IEEE Transactions on Antennas and Propagation ( IF 4.435 ) Pub Date : 2019-10-04 , DOI: 10.1109/tap.2019.2944553
Ying Yi; Jiaxu Chen; Kenichi Takahata

This article presents an electromagnetically powered stent designed for hyperthermia treatment of in-stent restenosis. The stent device based on medical-grade stainless steel serves as a radio frequency (RF) inductive receiver to produce mild heating wirelessly through resonant-coupling power transfer, while acting as a mechanical scaffold inside an artery similar to commercial stents. The device and its custom transmitter are prototyped and optimized to show efficient wireless power transfer and stent heating through in vitro tests. The inductive stent with its helical pattern is gold coated to achieve a $3.5\times$ higher quality ( $Q$ ) factor, improving heating performance of the device. The combinational use of independent resonant antennas with the power antenna is found to significantly boost stent temperature by up to 96% with an intermediate tissue layer. Upon matching the frequencies at which the $Q$ factors of the inductive stent, power antenna, and booster antenna are peaked, the stent excited through 10 mm-thick tissue exhibits a temperature increase of 18 °C, well over a necessary level for targeted hyperthermia treatment. The prototype achieves heating efficiencies (HEs) of 15.5–3.2 °C/W with a tissue thickness of 5–15 mm. These results indicate that the proposed resonant-heating stent system with the prototyped transmitter is promising for further development toward its clinical application.

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