RF H-FIELD FLUXTUBES FOR SAFE AND CONTROLLED HYPERTHERMIA

A novel low RF frequency hyperthermia applicator is presented. This co nsists of a toroidal resonator on the conductive wall of which two rad ial treatment ports are cut away to generate an air gap. This exposes the body part to be treated to the RF magnetic field fluxtube of high density and uniformity that is circulating uninterrupted within the to roidal walls through the air gap. The configuration of the port-body a ssembly may be adjusted for steering the induced heating field over th e target while maintaining the effectual energy coupling with the tiss ue. The results of the assessment of a 27 MHz high density fluxtube on cylindrical all-muscle and fat-muscle phantoms show that a purely ind uctive type of heating occurs, which is substantially localized inside the muscle tissue and a water bolus is unnecessary in the absence of stray E-fields. Heating field optimization is accomplished with fluxtu be cross-section, pathway and air gap shaping. It is also shown that t he superimposition of a uni-directional coherent field created by pass ive auxiliary electrodes to the fluxtube-induced solenoidal field prod uces a constructive interference and enhanced and more penetrating loc alized heating.