A low profile ferrite sleeve choke for localized power delivery during hyperthermia using coaxial wire antenna

In this paper, a compact (0.24λ) customized ferrite sleeve choke with very low radial profile (thickness of 0.3 mm) is reported for intracavitary hyperthermia treatment at 915 MHz. The ferrite choke is used to design a dielectric loaded monopole antenna for delivering targeted power deposition at the cervix using an intracavitary applicator with 15○bend. Antenna surface current distribution, volume loss density, local specific absorption rate (SAR) in tissue, and applicator power reflection were used to assess the applicator performance. Applicator power coupling characteristics in tissue indicate a power reflection coefficient of -27 dB and 25% axial specific absorption rate coverage of 41 mm at 915 MHz. Thermal simulations indicate spherical heating volume at the distal end of the applicator confining the heating zone to the cervix.