Intracavitary microwave hyperthermia applicator with resistive coating for targeted heat delivery

Targeted heating and minimum invasiveness are desired characteristics for interstitial or intracavitary hyperthermia and ablation applicators. Coaxial monopole wire antennas provide minimum invasiveness, but the current induced on the outer conductor radiates backwards and extends the heating zone beyond the antenna active zone. Coaxial BALUN is widely used for choking the back current at the cost of increased applicator size and invasiveness in the tissue. In this paper, we investigate the scope of resistive coating on the outer conductor of a 915 MHz monopole antenna proposed for hyperthermia treatment. Numerical simulations are presented for a conventional coaxial monopole with and without a thin coating of PEDOT:PSS to study the influence of the resistive coating on suppressing the current induced on the outer conductor and tissue specific absorption rate (SAR) for varying antenna insertion depth in the tissue.