Gamma knife treatment of tumors is gradually being used clinically. The advantage of gamma knife treatment of tumors is that gamma knife rays are precisely targeted to kill tumor cells at once, lethally, while there is basically no damage to the surrounding normal tissues. Gamma knife treatment of lung, liver, pancreas, kidney and other parenchymal organs tumor effect, comparable to the effect of surgery, but should not be used in the cavity organs and spinal cord parts of the tumor. There are three reasons why it is called body gamma knife: first, the cobalt 60 radiation source of gamma rays as the energy source; second, it can treat tumors in all parts of the body other than the head, which is different from the head gamma knife; third, the 30 beams of gamma rays radiated by 30 cobalt 60 radiation sources are focused to one point, forming a high-intensity energy area at the focal point, and the energy outside the focal point decays rapidly as the distance increases. Body gamma knife is a new type of stereotactic radiotherapy technology based on the principle of rotating head gamma knife. However, it must be noted that Gamma Knife is not suitable for any case of tumor, and Gamma Knife is not suitable for cases where the tumor is too large. This is because: when the tumor is too large, the tumor lesion is mixed with the surrounding normal tissue and the infiltration of the tumor lesion is large. Gamma knife irradiation will cause damage to the surrounding normal tissues. This prevents the gamma knife treatment from raising the dose, which has an impact on the efficacy.