I. Principle of radiofrequency ablation technology and STARmed radiofrequency ablation treatment system Radiofrequency ablation (rfa) is a kind of minimally invasive interventional treatment method, which was firstly reported by rossi and mc gahan in 1990 for the ablation of animal liver tissues and then used to treat human liver tumors. Currently, rfa technology has been widely used to treat diseases of various organs throughout the body, which not only can inactivate tumors, but also reduce tumor load for pain relief and hormone secretion, etc. In addition, there are studies on its application to non-tumor diseases such as hypersplenism (hypersplenism). The ions and polar macromolecules in the tissues around the tumor are heated up to the effective treatment temperature range and maintained for a certain period of time to kill the tumor cells. 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 and red blood cells, thus playing a non-specific tumor killing role. STARmed RF ablation treatment system is the only RF treatment system that can use mobile ablation technology, and the RF ablation electrode needles used for thyroid nodule ablation treatment are 18G (1.25 mm diameter) hollow water circulation electrode needles, which can effectively avoid carbonization of tissues during RF ablation while reducing trauma, and is conducive to the absorption and shrinkage of thyroid nodules after treatment; the only RF electrode needle that can be used unilaterally. The only RF electrode needle that can ablate unilaterally, when ablating nodules such as those next to the recurrent laryngeal nerve, can only target the lesion to form a half-moon ablation zone without ablating the important organ tissues such as the recurrent laryngeal nerve. In the treatment, the main unit adopts continuous output mode and automatic impedance-controlled power output to ensure that the electrode needle can be moved for ablation (Moving Shot), which is a technique of ablating benign thyroid nodules and tumors by conceiving them as multiple small ablation units and sending the electrode needle from the isthmus to the distal end of the nodule and retreating the needle as it moves. The sequence of ultrasound-guided mobile radiofrequency ablation of benign thyroid nodules and tumors: down-middle-up, far-near, and missed supplement, can achieve complete ablation coverage of nodules and tumors. In 2000, Hajime Kanauchi et al. firstly performed ultrasound-guided thyroid radiofrequency ablation on a 20 kg pig, and only made a simple observation on the effectiveness and safety of thyroid radiofrequency ablation at that time. The results showed that radiofrequency ablation of the thyroid gland did not cause abnormal release of thyroid hormones, and no short-term (within 3 months) signs of autoimmune abnormalities were observed. The results showed that radiofrequency ablation of the thyroid gland did not cause abnormal release of thyroid hormones, and no autoimmune abnormalities were observed in the short term (within 3 months). Although animal studies have confirmed the effectiveness and safety of radiofrequency ablation of the thyroid gland, there are still some aspects that need to be further investigated, such as the imaging and histopathological patterns of the radiofrequency thyroid destruction; the circumstances under which injury to the recurrent laryngeal nerve and parathyroid gland is likely to occur (especially in the vicinity of the thyroid peritoneum); the regression and prognosis of injury to the recurrent laryngeal nerve and parathyroid gland; and whether radiofrequency treatment will The risk of surgical treatment after treatment failure is increased by increasing adhesions between the thyroid gland and the surrounding tissues; whether radiofrequency treatment will increase infection and autoimmune reaction, etc. Clinical application of radiofrequency ablation of thyroid gland In 2001, Dupuy D et al. firstly used radiofrequency ablation for the treatment of recurrence of well-differentiated thyroid cancer after surgery. Currently, the main clinical application of radiofrequency ablation for thyroid disease is ultrasound-guided radiofrequency ablation, and the equipment is mainly cold circulation radiofrequency system. Nowadays, it is mainly used to treat some 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; with the continuous development of ultrasound technology, high frequency ultrasound can now clearly display thyroid nodules of 2mm in diameter. When performing radiofrequency ablation, the irregular echogenic enhancement of the needle tip can be clearly seen under ultrasound guidance, 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. However, for tumors close to the peritoneum of the thyroid gland, because of the proximity to the recurrent laryngeal nerve and the parathyroid gland, the operation is often more cautious and the treatment is easily incomplete. The effect of radiofrequency ablation treatment of thyroid gland Using STARmed radiofrequency ablation treatment system, Jeong et al. performed ultrasound-guided percutaneous radiofrequency ablation of 301 benign thyroid nodules in 236 patients with normal thyroid function, and the nodule volume was reduced by 84.11% with no serious complications during the follow-up period of 1-41 months, which confirmed that radiofrequency ablation is a safe and Baek et al. showed a 4-year average reduction of 93.4% in nodule volume and significant aesthetic and symptomatic relief in 111 patients with 126 nonfunctioning benign thyroid nodules at 49 months of follow-up; in their study of the number of ablations, they suggested that complete ablation of nodules <20 mm could be achieved in a single visit; in a joint study of 13 centers, they concluded that 14 nodules could be ablated in a single visit. In a study of complications, it was concluded that 1459 patients had 1543 lesions ablated by radiofrequency with a complication rate of only 3.3%. Although the effectiveness and feasibility of thyroid radiofrequency treatment have been clinically confirmed, and there are some reports on the follow-up results of the treatment effect, but due to the small number of reported cases, the follow-up time is not long, and the lack of clinical control studies on the short-term and long-term treatment effects with surgery and other treatment methods, the recent and long-term effects of the treatment, the evaluation time and methods of the post-treatment effects need to be further studied. V. Complications of radiofrequency ablation of the thyroid Jeong et al. reported that in 236 cases of benign thyroid nodules treated by radiofrequency ablation, 3 patients (1.3%) had temporary postoperative paralysis of the recurrent laryngeal nerve, which returned to normal in about 2 months. In a joint 13-center study of complications, 1459 patients had 1543 lesions ablated with a complication rate of 3.3%. Currently, radiofrequency ablation of the thyroid gland has been carried out for a limited time and scope in clinical practice, and the radiofrequency needle is often far away from the thyroid tegument, generally above 12.5 px, in order to avoid damage to the recurrent laryngeal nerve during treatment. This will definitely limit the scope of application and affect the results. In addition, the main principle of radiofrequency ablation technology is the coagulative necrosis of abnormal tissues caused by the thermal effect, and both the thermal response and coagulative necrosis can cause the stress response of the body, which may lead to autoimmune response of the thyroid gland and cause autoimmune diseases of the thyroid gland, and whether there will be adverse reactions in this regard remains to be verified. Other common adverse reactions after thyroid radiofrequency ablation treatment include pain, subcutaneous hematoma, etc. However, they are mostly temporary and the symptoms tend to disappear after a relatively short period of time (usually about 1 week) and have little effect. Conclusion: Although the effectiveness and feasibility of radiofrequency thyroid treatment has been confirmed and has been gradually carried out in clinical practice, and its minimally invasive nature compared to surgery is undeniable, due to its relatively short application time, a set of proven norms has not yet been formed, its safety and scope of application, the occurrence of complications, whether treatment failure will increase the risk and difficulty of surgical treatment, the chance of recurrence and long-term However, due to the relatively short period of time, a set of effective regulations has not yet been formed.