High Intensity Focused Ultrasound Therapy System (HIFU), referred to as ultrasound knife, is a high-tech product with independent intellectual property rights in China and a key scientific and technological research project of the National Ninth Five-Year Plan. It uses the strong penetrating power of ultrasound to make hundreds of high-energy ultrasound beams through the ultrasound transmitter, like gathering solar energy to make the focal point converge on the tumor tissue, using high-energy ultrasound cavitation to rupture the cell membrane of the tumor tissue, and at the same time, the high-energy ultrasound releases huge energy which is rapidly converted into heat energy, and the temperature of the tumor tissue at the focal point instantly reaches 70 ℃ -100 ℃, which destroys the tumor tissue through high temperature to achieve the purpose of killing the tumor cells. The tumor cells are killed by high temperature, but the surrounding normal tissues are not affected. Let’s get to know this miraculous “knife” for tumor treatment. 1, through layers of obstacles, directly hit the tumor: ultrasonic knife has a set of tumor identification system, it can accurately detect the location and size of the tumor, the computer can automatically lock the tumor after receiving this information, under the control of the computer, ultrasonic waves can pass through the normal tissues of human body without damage to reach the tumor tissue, not only can kill the tumor cells, but also do not hurt the normal tissues around the tumor. When ultrasonic waves are transmitted in human body, the ultrasonic energy is absorbed by human body tissues and converted into heat energy (when sunbathing, light waves are absorbed by human body and converted into heat energy), normal human body tissues can take away most of the heat through effective blood circulation, thus the temperature change of normal tissues is small and slow, but tumor tissues, because the blood circulation is only 2%-15% of normal tissues, the blood circulation is very poor, because it is not the same as normal tissues. However, because the blood circulation of tumor tissues is only 2-15% of that of normal tissues, the blood circulation is very poor because it is not heat resistant and the temperature change is significant. This characteristic of tumor cells makes them an excellent target for “ultrasonic knife”. On the one hand, tumor cells undergo coagulative necrosis during “ultrasonic knife” treatment; on the other hand, their own blood vessels are also in a state of occlusion and coagulation, which deprives tumor cells of nutrition. The treatment is mainly carried out through several aspects. a. Hyperthermic effect: Normally, the critical point of lethal temperature of tumor cells is 42.5~43.0℃, while that of normal cells is 45℃. Different from low power focused ultrasound, HIFU therapy instrument can focus high intensity ultrasound energy on the treatment area, which can rapidly raise the temperature of the target area to over 70℃ within 0.5 seconds, thus making the proteins in the cells in the treatment area appear coagulative necrosis rapidly and producing the therapeutic effect. b. Cavitation effect: Through the strong expansion and atrophy movement of the bubble, it causes mechanical destruction of tumor cells. c. Immune effect: The necrotic tumor tissue, at the same time, can play the role of stimulating the body’s immunity and produce anti-tumor effect at a later stage. Compared with other means of tumor treatment, the advantages are: a. No invasiveness of surgical operation. b. High temperature, fast warming, accurate focusing, instant coagulation and necrosis of tumor tissues. c. No radiation damage and no need for protection. d. No toxic side effects of chemotherapy. e. Synergistic effect with radiotherapy. 2. Ultrasonic knife is so good, can it treat all cancers? Ultrasonic knife is mainly applicable to various tumors in the abdomen, pelvis and body surface, and most of the solid tumors in the abdominal cavity, pelvis and body surface at a depth of 3-15cm from the body surface can be treated with focused ultrasound; for patients who are old and weak, or have obvious complications in other organs of the body (such as liver, kidney, pancreas, etc.) and other obvious contraindications to surgery can also be treated; for middle and late stage tumors, in addition to local killing of the primary tumor cells, it can also be used for the treatment of cancer. In addition to local killing of primary tumor cells, it can also be combined with radiotherapy and chemotherapy to improve the therapeutic effect of radiotherapy and chemotherapy; for tumors that cannot be removed by surgery, are insensitive to radiotherapy and chemotherapy, or recur after surgery and do not want to undergo surgery again, at this time, high-intensity focused ultrasound knife can shrink or necrosis the tumor entity, which is beneficial to alleviate symptoms, improve the patient’s survival, improve muscle immunity and patient’s quality of life. It is currently applied to the treatment of uterine fibroids, uterine adenomyoma, breast tumors, pelvic and abdominal recurrent and metastatic parenchymal masses, pancreatic cancer, liver cancer, etc. 3. Adverse effects of ultrasonic knife: Because ultrasonic wave is a kind of mechanical wave and does not contain radiation, it is harmless to human body and has few side effects, only a few of which produce skin damage. Together with radiotherapy and chemotherapy, ultrasound knife not only does not exclude other treatments but also has synergistic effect with traditional radiotherapy because it is painless and has no toxic side effects, and the preferred radiotherapy is strong in killing oxygen-rich cells around tumor tissues, while it can do nothing to the oxygen-depleted cells in the central area. In contrast, ultrasonic knife is sensitive to the oxygen-depleted cells in the central area and less effective in killing the surrounding oxygen-rich cells. While radiotherapy is most sensitive to mitotic (M-phase) cells in cell division, ultrasonic knife is sensitive to synthetic (S-phase) cells and late synthetic (G2) cells that resist radiation. Ultrasonic knife heat therapy makes the tumor blood flow occlusion poorly causing heat accumulation, heat accumulation aggravates the tumor malnutrition, lack of oxygen and low PH environment, the expanded heat cytotoxic effect has the effect of destroying anti-radiation cells, further progressing the sensitivity of radiotherapy, it can be said that ultrasonic knife plays 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 ultrasound heating can lead to increased cell membrane activity, 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. At the same time, ultrasonic knife can reduce the recurrence and metastasis of tumor.