Effects of choke in minimally-invasive small-profile microwave ablation applicators

Microwave ablation is a fast-growing hyperthermic treatment option for unresectable malignancies. From pioneering percutaneous microwave procedures to treat liver lesions, nowadays several new clinical indications are emerging. The spread of microwave ablation in clinical practice is growing alongside with the requirement for minimally-invasive procedures and, consequently, minimally invasive microwave applicators. Tri-axial structures and chokes have been proposed in the literature as techniques to improve the ablation performance of needle-shaped antennas. In this paper, those techniques are compared in terms of electric field distribution, return currents on the feed cable and specific absorption rate when integrated into an 18-gauge applicator.