Selective and regulated RF heating of stent toward endohyperthermia treatment of in-stent restenosis
This thesis presents a novel active stent system with a selective radio frequency (RF)heating and temperature regulation capabilities. Such system is targeted at the application to endohyperthermia treatment for in-stent restenosis problems, providing a cheap and non-invasive long-term solution to the blood vessel blockage caused by a growth of scar tissue across the stent structure after implantation. The research work consists of two major portions. Firstly, a novel active stent device with
... stent device with ability of selective RF heating has been custom designed and explored. The device is formed by integrating a stainless-steel based stent with a flexible capacitor strip, which serves as a frequency-selective wireless heater controlled using a tuned RF electromagnetic field applied externally. The proof-of-concept prototype device has been developed based on micro-electromechanical systems (MEMS) fabrication processes; its electrical and thermal characteristics are studied thoroughly. The finalized device is tested and evaluated within an artificial artery for validating its potential feasibility of wireless stent hyperthermia.Secondly, a MEMS-based, thermally sensitive circuit breaker chip has been designed and fabricated for the active stent temperature regulation. The temperature of an active stent device can be managed within a certain range after integrated with the chip, offering the controllability of RF heating of the device. Customized design and packaging methods are used in the chip fabrication; the chip-stent integration technique is also explored. The finalized device is evaluated with in-vitro tests, showing its temporal capability and wireless reliability. The experiment result verifies device working principles and suggests a direction of future research on non-invasive endohyperthermia treatments for long-term restenosis management.