High-energy focused ultrasound therapy machine, referred to as ultrasound knife, is a key scientific and technological research project of the National Ninth Five-Year Plan, and a high-tech product with independent intellectual property rights in China. Our hepatobiliary surgery department has introduced ultrasonic knife equipment to treat many kinds of tumors without trauma, creating conditions for tumor surgical resection and providing a safe and effective method for tumor treatment, which is the first surgical unit in China to carry out this technology. The principle of ultrasound knife for tumor treatment ultrasound therapy belongs to the category of thermal therapy, as we all know, heating can treat tumor, but over the years, the development is slow and not well used in the clinic, the development of modern science has laid the foundation for tumor thermal therapy, also make its research application has been continuously developed, various thermal therapy devices have been introduced and used in the clinic, but due to the relatively low temperature, the efficacy is not lasting, unstable, etc. But due to the relatively low temperature, the therapeutic effect is not long-lasting, unstable and other reasons, and was left out, the nineties with the development of computers and other technologies, the level of thermal therapy machine has been greatly improved, so that the treatment temperature reached 60-100 ℃, the clinical achieved amazing results. This has drawn a dividing line in the history of thermal therapy, changing the traditional temperature between 41-45℃ to “high temperature therapy”, and the temperature above 60℃ is called “thermal therapy”. Ultrasonic knife is an excellent example of China’s thermal therapy technology, which has enabled China to reach the world’s leading level in the field of thermal therapy technology. It adopts ultrasound as energy source and gives full play to the characteristics of fat but not heat, easy temperature measurement, good penetrating performance, strong pointing and good focusing performance in the focusing process. In addition, it creates the cumulative treatment mode of point into line, line into surface and surface into body in the treatment application, which can kill the tumor of larger volume sequentially. It is a great progress in the treatment of various tumors. The advantages of ultrasonic knife treatment for tumors: (a) High temperature and fast warming. Ultrasonic knife treatment is a cellular level treatment, and some research shows that the inactivation time of cells at a temperature below 40℃ takes nearly 15 hours, at 50℃ the inactivation time is 3 minutes, at 60℃ the inactivation time is 3 seconds, at 70℃ the inactivation time of cells is 0.25 seconds, and at 100℃ the inactivation time of cells is only 0.1 seconds. The traditional thermal therapy technology can only be regarded as high temperature treatment, and the warming up is slow and the temperature is low, which cannot achieve the effect in the sense of real thermal therapy, while ultrasonic knife can make the temperature of tumor treatment site reach 70-100℃ in a short period of time by using acoustic trans-thermal energy, and the tumor cells will be denatured and necrotic instantly. (2) The non-invasive nature of ultrasonic knife for tumor treatment. The traditional thermal therapy technology requires anesthesia because of the high energy incident on the skin and pain during treatment. In this way, both doctors and patients need to bear the risk of anesthesia, which is not easy for patients to accept; 7-20% of skin is burned or even higher during traditional thermal therapy cannot be avoided; there are obvious complications of conventional thermal therapy, such as blood in stool and perforation during rectal cancer treatment, and hematuria after bladder cancer treatment. Due to the above reasons, its clinical application is greatly restricted, while ultrasonic knife has not found any pain and other suffering in nearly 1,000 tumor treatments, and the skin burn rate is 0. (3) Wide range of indications and large volume of tumors treated. Due to the disadvantages of traditional thermal therapy such as pain, burns and complications, the scope of treatment is greatly restricted, and only some tumors that are too small, generally not more than 3-9cm, are seen. It includes solid tumors of various organs in the abdominal cavity, pelvis, etc. The volume of single treatment has been expanded to 100-150mm, which is the highest level in the world, due to the “cumulative effect” under the computerized self-control of forming a dot into a line, a line into a surface, and a surface into a body. (4) Ultrasonic knife has a synergistic effect with radiotherapy and chemotherapy. Ultrasonic knife not only does not exclude other treatments but also has a synergistic effect with traditional radiotherapy and chemotherapy because it is painless and has no toxic side effects, and the preferred radiotherapy has a strong effect on killing oxygen-rich cells around the tumor tissues, while it can do nothing to the lack of oxygen cells in the central area. In contrast, ultrasonic knife is sensitive to the oxygen-depleted cells in the central area and relatively poor at killing the surrounding oxygen-rich cells. While radiotherapy is most sensitive to mitotic (M-phase) cells in cell division, ultrasound knife is sensitive to synthetic (S-phase) cells and late synthetic (G2) cells that resist radiation. Ultrasonic knife thermotherapy causes heat accumulation due to poor tumor blood flow atresia, and heat accumulation aggravates tumor malnutrition, lack of oxygen and low PH environment, and the expanded thermal cytotoxic effect has the effect of destroying radiation-resistant cells, which further increases the sensitivity of radiotherapy, and it can be said that ultrasonic knife has a sensitizing effect on radiotherapy. Secondly, ultrasonic knife heat therapy also has a sensitizing effect on chemotherapy and reduces the amount of drugs and side effects. Studies have shown that ultrasonic heating can lead to increased cell membrane flow, enhanced permeability, enhanced drug penetration and absorption, accelerated drug response, and reduced isolated cellular repair. Due to its sensitizing effect on drugs, the potency of the same dose of chemotherapeutic drugs is doubled or even increased hundreds of times. Therefore, ultrasonic knife thermal therapy can reduce the dosage of chemotherapeutic drugs to alleviate their side effects, and even make some drugs that have no killing effect on tumor cells become killing effect. In clinical practice, the combination of ultrasonic knife thermal therapy with local infusion chemotherapy and modern interventional therapy has largely improved the therapeutic effect of tumors. (5) Ultrasonic knife treatment can reduce the recurrence and metastasis of tumor. Killing local tumor is the fundamental purpose of tumor treatment including surgery and radiotherapy, but how to reduce the recurrence and metastasis of local tumor after killing is another more important issue, the recurrence of tumor is mainly formed by local residual cancer cells proliferating again after the tumor is removed or killed. In order to reduce local recurrence, the scope of resection should be expanded during surgery and the irradiation field should be increased during radiotherapy. However, due to the influence of tumor growth site and size, the scope of surgery cannot be expanded indefinitely; radiotherapy also limits the expansion of irradiation field due to its large side effects. Ultrasonic knife kills tumor cells at the cellular level and has no effect on the integrity of surrounding tissues and no toxic side effects after treatment, so it can relatively expand the treatment range, kill the infiltrating cells around the tumor and reduce recurrence. The metastasis of tumor is mostly caused by some cancer cells of the main tumor along the vascular lymphatic vessels or directly overflowing from the tumor body, forming free cells in the surrounding area and then proliferating and dividing to form tumor foci. In the process of tumor cell necrosis caused by ultrasonic knife heat therapy, it can produce endogenous tumor Zhiyuan to stimulate the immune system of the body and produce tumor antibody to kill tumor cells. All these suggest that ultrasound knife can reduce the recurrence and metastasis of tumor. In conclusion, high energy ultrasonic knife has the advantages of exact efficacy, accurate positioning, non-invasive, painless, wide range of indications, comfortable “surgery” without anesthesia, strong safety, high efficiency, easy operation and high technological content, and the local treatment of tumor is like radiotherapy, better than radiotherapy, like surgery, better than surgery, without toxic side effects, and without sequelae. It has no toxic side effects and no after-effects, and has synergistic effect with radiotherapy. It brings hope to tumor patients and is a revolution in tumor treatment. The HIFU ultrasonic ablation therapy can inactivate tumor tissues and achieve the effect of tumor “resection”; in addition, it can create good conditions for surgery and prevent tumor cell metastasis caused by intraoperative squeezing, and reduce bleeding.