Therapeutic Range Of Microwave Ablation Using Different Power In Vivo Rabbit Liver VX2 Tumor Implantation Model

Objective:Microwave ablation(MWA),a kind of local thermal ablation therapy,is another possible radical treatment besides surgery.It has the advantages of less trauma,repeatability,less influence on liver function.Since it is impossible to obtain a complete pathological specimen after microwave ablation to verify whether the tumor is completely cured,it is important to accurately grasp the ablation range.This study explore the practical scope of microwave ablation with different power in vivo experiments for single tumors less than 3cm,providing reference for future clinical ablation treatment operations.Method: 30 New Zealand white rabbits were randomly divided into 3 groups,guided by CT through the puncture method implanting VX2 sarcoma fragments into the left hepatic lobe,rabbit cage aquaculture in 10 days,CT scan confirmed,records of the left hepatic lobe VX2 sarcoma lesion size,location,the relationship between portal vein.Then used 10 cm microwave ablation needle puncture lesion middle position,with 40 W,50W,60 W power to microwave ablation of VX2 sarcoma respectively,pull out the ablation needle after three minutes therapy,CT scanning scope of review and record imaging ablation.The rabbit liver was dissected and isolated,and the macroscopic area was observed and recorded.Pathological sections were prepared by the ablation center,boundary area and edge position,and the necrosis and survival of tumor cells were observed under the microscope.Result: After microwave ablation,the visible ablative area was divided into acupuncture carbonized area,necrotic area and hyperemia area.After ablation at 40 W,50W and 60 W for3 minutes,the pathological range of complete necrosis was 1.86 cm,2.32 cm and 2.62 cm,respectively,which was smaller than the imaging range and the naked eye range.The closer the distance to the portal vein,the smaller the scope of microwave ablation caused by heat sink effect.Conclusion: The power commonly used in liver tumors microwave ablation was 40 W,50W60W during 3 minutes MWA,which lead the actual completely range respectively is 1.86 cm,2.32 cm,2.62 cm,portal venous blood flow of heat sink effect will narrow the scope of microwave ablation.Immediately after microwave ablation,there is error between CT ablation range and effective range,which suggest CT ablation range extend 0.8 cm to the edge of lesions in order to achieve the purpose of completely ablation,as far as possible to avoid incomplete treatment in tumor progression.