A Minimally Invasive Antenna for Microwave Ablation Therapies: Design, Performances, and Experimental Assessment

Abstract

A new coaxial antenna for microwave ablation therapies is proposed. The antenna design includes a miniaturized choke and an arrowhead cap to facilitate antenna insertion into the tissues. Antenna matching and the shape and dimension of the area of ablated tissue (thermal lesion) obtained in ex vivo conditions are evaluated both numerically and experimentally, finding an optimal agreement between numerical and experimental data. Results show that the antenna is well matched, and that it is able to produce a thermal lesion with an average length of 6.5 cm and an average diameter of 4.5 cm in ex vivo bovine liver when irradiates 60 W for 10 min. Finally, the dependence of antenna performances on possible changes in the antenna's structure is investigated, finding an optimal stability with respect to manufacturing tolerances and highlighting the fundamental role played by the antenna's choke.

Percutaneous Tumor Ablation Tools: Microwave, Radiofrequency, or Cryoablation—What Should You Use and Why?

“…Adequately powered 915-MHz and 2.45-GHz systems can create relatively large ablation zones, but the longer wavelength at 915 MHz typically results in a longer ablation zone (28,34,(36)(37)(38). In general, the greatest heating from any system occurs within 1 cm of the antenna.…”

Microwave coagulation therapy: the future is quite rosy

“…In an experimental study, this system produced thermal lesions of 6.5 cm × 4.5 cm in ex vivo bovine liver by delivering 60 W for 10 min. [6] A randomized prospective comparison of MCT and RFA reported significantly larger coagulation areas in vivo with MCT than with internally-cooled RFA, using a 16-gauge internallycooled, minichoked MCT antenna with a power output of 60-70 W and ablation time of 10 min. [7] Although energy delivery was underpowered with respect to the maximum power output of the system, MCT yielded ablation areas comparable to those previously reported by other authors who performed MCT using a power output of 100 W and a 14-gauge cooled shaft antenna without choke device.…”

Development of a Novel Switched-Mode 2.45 GHz Microwave Multiapplicator Ablation System

“…The power delivery device has a mechanically simple and rugged coaxial structure outlined in Figure 6 that consists of a dielectrically loaded monopole with a capacitive cap [19][20][21] fed by a coaxial line. The device derives from the one described in [18], where the radiating element was a simple linear monopole.…”