Research On The Temperature Control System Of Radiofrequency Ablation Instrument For Renal Denervation

At present, renal sympathetic denervation attracted the attention of manydoctors and medical device companies as a new treatment for resistant hypertension.To promote the new operation, it is needed to develop a radiofrequency ablationinstrument which meets the functional requrements. Renal sympathetic denervationusing ablation catheter to thermal ablate the nerve fibers distributed in the wall ofrenal artery. Since the nerve fibers distribute in the superficial part of the artery wall,it is important to heating nerve fibers stably and control the damage of the vasculartissue at the same time. Thus the realization of intelligent temperature control is themain technical problems in the design of ablation instrument.This thesis focuses on the design and research of the temperature controlsystem of radiofrequency ablation instrument for renal denervation. First weanalyzed the functional requirements of the control system, and an overall designwas conducted according to it. Then a RF signal generation platform was built basedon the DDS signal generation technology. We designed RF signal generator circuit,low-pass filter circuit and power amplifier circuit, which together comprise thepower output system, realizing the signal generation function. Meanwhile, in orderto achieve the temperature control function, a microprocessor control system andtemperature measurement modules were devised. Subsequently, we construct themathematical model of the system. According to the mathematical model, asimulation of PID temperature controller was implemented in the Matlab/Simulinkenvironment to obtain the PID controller’s parameters. Finally we proposed thetemperature control strategy based on the experimental platform, and in vitro tissueexperiment results verified the feasibility of the control strategies and algorithms.The experimental results showed that the initial temperature rising velocity,overshoot and temperature stability all can meet the expected requirements,verifying the validity of the control system.