Microwave intracavitary applicator using 434Â MHz conformal patch antennas for hyperthermia treatment of gynaecological cancers

Feasibility of a 434 MHz microwave intracavitary applicator with conformal patch antennas is presented for hyperthermia treatment of gynaecological cancers. 3D numerical modelling was used to design a 434 MHz resonant conformal rectangular patch on a cylindrical alumina substrate. A conformal array applicator designed using four conformal patch antennas was evaluated in muscle tissue phantom. Applicator measurements indicated that the conformal patch resonated at 434 MHz with power reflection coefficient ρ < −35 dB, penetration depth of 12 mm at 434 MHz and −10 dB bandwidth >40 MHz. Normalised power deposition in the applicator transverse (XY) plane yielded 25% Effective Field Size (EFS) of 180 and 175 mm2 in simulation and measurement, respectively, for excitation of single conformal patch. The 25% EFS for excitation of two antennas was 500 and 510 mm2 in simulation and measurement, respectively. Simulations and measurements suggest that the 434 MHz intracavitary microwave applicator with conformal patch antennas could be used to deliver adjustable and localised power deposition at the target sparing the surrounding healthy tissues.