Focused ultrasound thermal resection (thermal ablation) technique has similarity with focused ultrasound thermal therapy technique, that is, low energy ultrasound is focused to form a higher energy focus to heat the target tissue (usually tumor tissue) to achieve the treatment purpose. Therefore, the two can be easily confused, especially for lay people. In essence the two are fundamentally different, and their differences are described below. The purpose of focused ultrasound thermal resection is to “thermally remove” (thermally ablate) the target tissue, usually at a temperature greater than or equal to 60C degrees. The target tissue is seen pathologically as coagulative necrosis, i.e., coagulation of target tissue proteins, which is irreversible thermal damage that causes necrosis of all cells in the target area. In contrast, focused ultrasound thermotherapy is to heat up the target tissue to above 42C degrees and below 50 degrees, which increases the sensitivity of cells to other damage factors (radiotherapy, chemotherapy, etc.) and cannot completely kill tumor cells even if the heating time is extended. Therefore, in terms of clinical application, focused ultrasound thermal resection can be used as a major local treatment in an effort to obtain radical cure or substantial tumor destruction, and can be used for tumor treatment alone. In contrast, focused ultrasound thermotherapy is a sensitizing measure to chemotherapy and radiotherapy, i.e., an adjuvant treatment, which cannot be applied alone and has a very limited effect and potential to increase metastasis when applied alone. Comparing from the technical aspect: the biggest challenge of the current physical therapy technology of using heat to treat tumors is to deposit enough thermal dose in a certain volume of target tissues to make them heated to a sufficient temperature, which is mainly affected by the heterogeneity of tumor tissues and blood perfusion, i.e. different tumors or different parts of the same tumor and different blood perfusion of tumors have a great influence on the thermal dose deposition, even if different tumors or different parts of the same tumor are heated to a sufficient temperature. The thermal dose required to warm up the tumor to the same temperature varies greatly between different tumors or different parts of the same tumor as well as different blood perfusion of the tumor, especially when the temperature is above 60C degrees. Therefore, the technology required for focused ultrasound thermotherapy is low, while the technology required for focused ultrasound thermal resection is very high. In other words, focused ultrasound thermotherapy is the primary stage of focused ultrasound treatment technology, while focused ultrasound thermal resection is the highest form of focused ultrasound tumor, which can become focused ultrasound thermotherapy after reducing the treatment dose. From the history of clinical application: Focused ultrasound thermotherapy was approved to enter the clinic by FAD in 1986, and the main researcher is Kullervo .Hynynen, who has been engaged in the research of focused ultrasound thermal resection at present. The focused ultrasound thermal resection device he developed was approved by the FDA to enter clinical trials in 2001 and approved to enter the market in 2003, becoming the first foreign focused ultrasound thermal ablation device to enter the clinic. Focused ultrasound thermal ablation in China, entered the clinical trial in 1997 and was approved by SFDA to enter the market in 1999. From the monitoring of the treatment process: all thermal ablation treatments (including focused ultrasound thermal resection) are monitored in real time for two purposes: to determine the location of the lesion and guide the treatment as well as to control the deposition of thermal dose. There are two methods to control the deposition of thermal dose, one is to use MRI temperature measurement to reflect the thermal dose of the target area, when the temperature of the target area reaches 60 degrees or above, it suggests coagulative necrosis of the target tissue; the other method is to use ultrasound to observe the grayscale change of the target area, when the grayscale of the target area increases to a certain value after treatment, it indicates coagulative necrosis of the target tissue. In contrast, focused ultrasound thermotherapy with ultrasound image monitoring does not have sufficient grayscale changes in the target area; therefore, focused ultrasound treatment without grayscale changes in the target area is focused ultrasound thermotherapy, not focused ultrasound thermal resection. From follow-up imaging: focused ultrasound thermotherapy usually uses non-functional imaging (such as ultrasound, plain CT or MRI) to determine the treatment effect based on the volume change of the target tumor, and does not emphasize whether the target tumor is necrotic, i.e. whether this target tumor is alive or not. Focused ultrasound ablation therapy must be based on functional imaging (e.g., ultrasonography, enhanced CT or MRI, and radionuclide imaging) to determine whether the target tumor is necrotic as well as its volume change. After focused ultrasound thermal resection, whole tumor tissue necrosis can be seen on functional imaging, while after focused ultrasound thermal therapy, whole tumor tissue necrosis cannot be seen on functional imaging. In terms of the number of treatments: focused ultrasound thermal resection is mainly a one-time treatment, while focused ultrasound thermal therapy requires multiple treatments with multiple irradiation of radiotherapy or chemotherapy administration time. Usually it is 1 treatment every 1 – 7 days. It is against the principle of tumor treatment to treat malignant tumors with focused ultrasound thermal therapy alone. From the clinical protocol: focused ultrasound thermal resection is: chemotherapy (1-5 courses) + focused ultrasound thermal resection + chemotherapy (3–6 courses) or radiation therapy (below 45GY) + focused ultrasound thermal resection + radiation therapy. Focused ultrasound thermotherapy: administration of chemotherapy drugs + thermotherapy + administration of drugs + thermotherapy …… + administration of drugs + thermotherapy (the number of days of administration of a course of chemotherapy drugs determines the number of treatments), radiotherapy + thermotherapy + radiotherapy + thermotherapy + …… + radiotherapy + thermotherapy (the number of treatments of thermotherapy is determined by the number of radiotherapy number of treatments). In terms of indications and contraindications: focused ultrasound thermal resection is indicated for solid tumors of substantial tissues and organs, and is contraindicated for the treatment of tumors of air-containing cavity organs. Because thermal resection leads to coagulative necrosis of tissues, it may lead to perforation of air-containing cavity organs. In contrast, focused ultrasound thermotherapy only leads to increased sensitivity of the target tissue cells to other treatments, accompanied by reversible cell damage, i.e., the damaged cells can be repaired, and the repair can avoid the perforation of air-containing cavity organs on the one hand, and tumor cell growth on the other. Therefore, the possibility of cavity organ perforation is relatively small when focused ultrasound thermotherapy is used for tumor treatment of gas-containing cavity organs, but it must be combined with other tumor treatments (radiotherapy or chemotherapy, etc.), and focused ultrasound thermotherapy alone, i.e., not combined with chemotherapy and radiotherapy is a risk of tumor dissemination. From the viewpoint of clinical effect: Since focused ultrasound thermal resection causes necrosis of the whole tumor, it can be a local “curative” treatment for the local target tumor, i.e. local complete thermal resection (complete inactivation of the local tumor mass), which is equivalent to the complete resection of the local tumor by surgery. According to the sensitivity of the tumor to other treatments, combined with or without other tumor treatments, the purpose of “curing” the tumor is achieved. In contrast, focused ultrasound thermotherapy is only a sensitizing effect to radiotherapy or chemotherapy, and it is difficult to achieve “cure” for solid tumors of substantial tissues and organs.