Design and Experimentation of an Epidermal RFID-based Thermal Monitoring Sheet (R-TMS) for Microwave Hyperthermia

Hyperthermia is a widely used anti-cancer treatment that exploits the interactions between high-power electromagnetic fields and the human tissues to locally release a great amount of power in the underlying tissue regions. Dangerous hotspots may occur within the skin, and hence continuous monitoring of the superficial temperature distribution is required throughout the treatment. Current Thermal Monitoring Sheets (TMSs), that are grids of many wired temperature sensors, have some limitations in terms of poor spatial resolution and high thermal conduction errors. Passive Ultra High Frequency (UHF) Radio Frequency IDentification (RFID) devices could offer an attractive alternative thanks to their wireless nature and low invasiveness. The preliminary design and experimentation of an RFID-based Thermal Monitoring Sheet (R-TMS) are presented in this paper as a Frequency Selective Surface (FSS). It comprises a planar array of circular loop antennas with temperature-sensing-oriented RFID microchips, that are capable to guarantee a stable link and to outperform the temperature spatial resolution of the state-of-the-art wired TMS.