Liver cancer is a common malignant tumor and is one of the most prevalent tumors in China. There is no particularly good treatment method for liver cancer, and surgery or interventional treatment is generally preferred. Which liver cancer and liver metastatic cancer can be treated by gamma knife surgery? 1. Indications for gamma knife surgery for primary liver cancer ① The nature of liver cancer has been diagnosed by imaging or pathology, no regional lymph node metastasis or distant metastasis, and the lesion is relatively limited; ② Patients with liver cancer cannot tolerate or refuse conventional radiotherapy; ③ Failure of liver cancer surgery or tumor residue after surgery, or tumor recurrence; ④ Tumor dynamics with breathing is less than 10 mm, and patients can lie down for more than half an hour; ⑤ “KS score greater than or equal to 60; ⑥ Aging or other diseases can not tolerate surgery or refuse surgery; ⑦ Small hepatocellular carcinoma (diameter <1.0cm) with clear boundary, the patient can not tolerate or refuse surgery, surgery can not be removed. 2, the indications for gamma knife surgery for liver metastases ① a clear history of primary tumor, the diagnosis of occupying lesions in the liver is clear or other concomitant tumors are basically excluded; ② the number of lesions ≤ 5; ③ spherical foci with lesion diameter < 40mm; ④ liver function classification and liver reserve function Child-Pugh A, B grade, the expected patient survival time > 3 months; ⑤ the maximum respiratory mobility of the tumor ≤ +-5mm. 3.How to improve the efficiency of Gamma Knife surgery for liver cancer Under the condition, increasing the fractionated dose and shortening the treatment course is one of the important time and dose splitting patterns for essential organ tumors, and the treatment of liver cancer is no exception, generally the fractionated dose is 3-15Gy, depending on the size, location and liver function of the tumor. Thus, this fractionation mode is used when small hepatocellular carcinoma or liver metastases and liver function are relatively good, which can improve the local control rate without causing radiation damage. It is understood that the current 5-year survival rate of surgical treatment of liver cancer with a diameter less than or equal to 5 cm is about 70%, and the 1, 2 and 3-year survival rate of whole-body gamma knife surgery for stage I/II liver cancer is over 90%. With the progress of gamma knife radiotherapy technology, many small hepatocellular carcinomas that cannot be operated in early stage can be cured radically with modern radiotherapy and less damage to liver function.