Research On Key Technologies Of Radio Frequency Ablation System

RF ablation system was a kind of electronic medical equipment widely applied to various kinds of disease treatment.Since traditional ablation equipment had low output efficiency,poor control accuracy,difficult operation and other problems.Hence,it promoted R&D of high-performance ablation equipment.This paper aimed at the defects of traditional equipment and took R&D for key technologies of operative RF ablation system.Additionally,it introduced a type RF ablation operation system which was widely applied in minimally invasive surgical ablation field,featured of wide application,good treatment effects and convenient operation,and could produce different levels of AC high-frequency voltage signals.This paper started from the output of high-frequency AC.Based on in-depth study of basic topology of voltage conversion,it proposed a kind of cascade circuit with effective Buck step-down and push-pull inverter architecture.Furthermore,it described the working principles and structures of all circuit parts and the parameters design process in details.The circuit could realize voltage regulation through changing PWM duty cycle,and voltage feedback and PID circuit compensation could improve the circuit static and dynamic performance.Additionally,the push-pull circuit could realize inverter output.With working principle analysis and circuit simulation,it verified the feasibility of circuit design scheme.With detailed design of all circuit module parameters,circuit construction and writing of processor software codes,a prototype was researched and developed finally.This paper illustrated the problems appeared in the circuit test process and positions which should be paid attention,and analyzed the measured waveform and data of the system.The system finally realized two kinds of outputs,100 kHz and 450 kHz,with voltage peak-peak range of 60 ~ 300 V,output ripple voltage control below 200 mV and controlled maximum output power of 150 W.It improved the output efficiency effectively.Additionally,the static and dynamic performance of the system was improved by improving the voltage feedback control link.The system had two kinds of working modes,ablation and coagulation.Furthermore,simulated surgical test was performed on in vitro fresh pork to simulate tumor cutting and excellent results of cutting ablation and coagulation were obtained.The system operation was stable and the full load output efficiency was above 90%.Hence,it could be applied in clinical surgical ablation field.