1.Principle of radiofrequency ablation technology Radiofrequency ablation (RFA) is a kind of minimally invasive interventional treatment method, and RFA technology has been widely used in treating diseases of various organs of the body, which can inactivate tumors and reduce tumor load to achieve pain relief and reduce hormone secretion, etc. RFA belongs to the category of tumor thermal therapy, and its basic principle is to use thermal energy to destroy tumor tissues. The basic principle of RFA is to use thermal energy to destroy tumor tissues. At the same time, the RF thermal effect can make the blood vessels in the surrounding tissues coagulate and form a reaction zone, so that they cannot supply blood to the tumor and prevent tumor metastasis. In addition, RFA can not only kill tumor, but also enhance the immune status of T lymphocytes, NK cells, red blood cells and so on, thus playing a non-specific tumor killing role. 2.Clinical application of thyroid radiofrequency ablation technology At present, the main clinical application for thyroid disease treatment is B-ultrasound-guided radiofrequency ablation, which mostly uses local anesthesia with lidocaine before operation. It is mainly used for the treatment of relatively small benign nodules, some autonomous high functional tumors, thyroid cancer that cannot be completely removed or thyroid cancer that recurs after surgery and patients who do not want to operate, and large nodules that need to be reduced to achieve a cosmetic effect on the neck; high frequency ultrasound can clearly show thyroid nodules with a diameter of 2 mm. When performing radiofrequency ablation, the B-ultrasound guidance can clearly show the irregular echogenic enhancement at the tip of the needle, which can roughly determine the scope of tissue coagulation and necrosis eventually caused, and ensure that the operating range is far away from the thyroid peritoneum and the positioning is relatively accurate. This can avoid damage to the recurrent laryngeal nerve; and the radiofrequency needle is very slim and will not leave a scar on the neck.