Study On Effective Heating Area Control Method Of Medical Microwave Ablation

The high morbidity and mortality of cancer seriously threaten human life and health.Microwave ablation has gradually become the main method of treating cancer in the clinic.Existing technology has a small effective ablation range and low ablation roundness,and cannot effectively control the effective ablation area,which hinders the further development of microwave ablation technology.The main goal of this study is to accurately control the effective ablation area.This paper mainly includes the following three contribution:1.Developed an ablation needle-based ablation hardware platform to increase the maximum ablation range and ablation roundness.Developed an embedded microwave ablation instrument with stable output power,low power error,and fast power response.A new type of ablation needle was designed to increase the maximum ablation diameter of isolated pig liver from conventional 3 cm to 6.6 cm.0.6 increased to about 0.95;through the impedance matching optimization,the standing wave ratio of the entire system was reduced from the usual 3 to about 1.5,thereby improving the ablation efficiency from 75%to 95%.2.Established mathematical static and dynamic models of ablation process.By modeling and simulating the above-mentioned microwave ablation platform in COMSOL,the problem that the ablation boundary is difficult to define is solved,the ablation discrete data is obtained,and then the mathematical expressions of the ablation size and ablation time under different continuous powers are obtained.And test the ablation hardware platform and mathematical model through three-dimensional ablation experiment of pig liver.3.An ablation area control algorithm is proposed.The ablation experiment of fresh isolated pig liver was used to modify the simulated ablation model to obtain the precise relationship between the ablation size and the ablation time under different power inputs,so as to perform continuous open-loop control of constant power;optimize the control algorithm based on the reflected voltage An intermittent constant power control algorithm and a variable power control algorithm are proposed.Experiments show that the hardware platform and three control algorithms developed based on this paper can reach the control target of more accurate ablation boundaries.