Electromagnetic and thermal models of a water-cooled dipole radiating in a biological tissue

An insulated, water-cooled dipole, radiating in a biological tissue, is analyzed with a theoretical electromagnetic and thermal model. The SAR (specific absorption rate) and temperature distributions are calculated taking into account the effect of the water flowing inside the applicator. The steady-state temperatures in a dissipative medium, interacting with the dipole, are evaluated for several thicknesses of the external casing, water temperatures, and blood perfusions. A correct design of the external casing thickness and a proper choice of the temperature and flow velocity of water make it possible to control the wall temperature of the applicator within physiological limits. The influence of the blood perfusion on the temperature distribution is investigated.