A cylindrical shaped theranostic applicator for percutaneous microwave ablation

The design of a minimally invasive surgery tool for the detection and treatment of cancerous tissue is presented. The planar structure is based on spiral resonators, with an operating frequency range from 4 GHz to 6 GHz, excited by a conventional coplanar waveguide to, firstly, extract resonance shifts to gain information about permittivity changes in the surrounded tissue. As second feature, tumorous cells can be eradicated by performing thermal ablation. The focus of this work lies in the integration of the structure in a needle-like tool with a diameter of 2.1 mm for percutaneous interventions by using a flexible substrate that is rolled into the desired shape. Full wave simulations of the planar and cylindrical structures are presented. Furthermore, initial measurements are performed to evaluate the detection and treatment mode characteristics. A dimension of the ablation zone of 2.9 cm³ is achieved with an input power of 20 W for 4min exposure.