Calculations of Heating Patterns of Interstitial Antenna for Brain Tumors Hyperthermia Treatment Planning

In this paper a complete thermal analysis has been performed considering an interstitial short dipole antenna implanted inside the human head for brain tumors hyperthermia. For accurate computations, a finite-difference time-domain (FDTD) anatomically based head model is used for analysis. The model composed of seventeen different tissue types with resolution 2 mm. A spherical tumor model with 1.5 cm diameter is assumed inside the cerebellum with dielectric constant 2-5 times the surrounding normal tissue. The specific absorption rate (SAR) distribution in the human head was determined using FDTD method. The temperature rise around the dipole is calculated. Specifically the bioheat equation was solved also using the FDTD method. The dipole was modeled as a thin wire short dipole with radius 0.3 mm and half-length 3.5 mm operating at 400 MHz. 0.45 W input power is used, to elevate the tumor temperature to nearly 43degC. Numerical results showing the validation of the developed computer program are introduced. SAR and temperature distributions inside the tumor and the surrounding normal tissues are presented