The Research On Key Techniques Of Microwave Conformal Ablation And Dose Control Of Tumors

Microwave ablation technology has advantages of minimal trauma,accuracy,rapid warming and little side effects,which is widely used in the tumor treatment such as liver cancer and lung cancer.Aiming at the tumors of specific shape and special location,precise control of microwave thermal dose and complete conformal ablation of irregular tumors is an urgent clinical problem to be solved at present.In this paper,433 MHz microwave ablation needles were designed and its ablation effect was effectively verified by ex vivo swine liver experiment in the microwave ablation system,which was suitable for the conformal ablation treatment of liver tumors.Furthermore,an efficient dose control simulation model of microwave ablation was established.It was helpful for the intuitive understanding of ablation effects under different thermal doses before surgery.The main contents of this paper: 1.We designed 433 MHz monopole and slot microwave antennas.The fitted puncture head,stainless steel bar,dielectric bushing,cooling water unit and handle were used to form a complete water-cooled microwave ablation needle.2.A dose control simulation model of microwave ablation was accurately constructed and was encapsulate into a simulation App with friendly interface using COMSOL software,which could rapidly obtain the ablation temperature field and effective ablation volumes under different thermal doses.3.The conformal ablation effect of 433 MHz water-cooled microwave ablation needle was verified by the ex vivo swine liver experiment.The simulation model was verified effectively by experiment.4.Dielectric properties of liver tissues under different thermal damage levels at 433 MHz frequency had been measured by the coaxial probe method,which not only provided help for the detection and treatment of tumor tissues,but also provided parameter support for the accurate establishment of temperature field.The main innovations of this paper: 1.We innovatively design microwave ablation needles at medical microwave frequency of 433 MHz,which is suitable for the conformal ablation of gourd-shaped liver tumors close to organs at risk and the strip-shaped tumors.2.In order to make simulation results of temperature field more reliable,the electrical and thermal characteristic parameters varying with temperature are used in the simulation model,which achieves more accurate thermal dose control.