Wireless Skin Temperature Monitoring for Microwave Hyperthermia: Feasibility Study of an Epidermal RFID Sensor Grid

Microwave hyperthermia is an emerging anticancer therapy with the potential to improve the outcomes of chemotherapy and radiation therapy. However, the application of microwave energy to the skin can cause thermal damage and discomfort to patients. To address this issue, a novel epidermal RFID-based Thermal Monitoring Sheet (R-TMS) is proposed as a wireless, low-cost, and non-invasive solution for monitoring skin temperature during the treatment. R-TMS is a planar grid of RFID antennas embedded with temperature-sensing Integrated Circuits (ICs), operating in the UHF band, and designed to be placed in direct contact with the skin to provide a real-time temperature spatial map. Simulations demonstrated that the R-TMS introduces minimal variations in the Effective Field Size (EFS) and Effective Heating Depth (EHD), indicating its compatibility with the therapy. Moreover, Specific Absorption Rate (SAR) distribution analysis revealed a slight local increment in SAR on the skin, but the resulting temperature rise variation remained within acceptable limits. Finally, experimental measurements preliminary demonstrate its accuracy and reliability for skin temperature monitoring.