According to clinical studies, radiotherapy treatment contributes 51% of curable malignant tumors, even more than surgery (49%), so it can be understood that radiotherapy is a very effective treatment for malignant tumors and is not a conservative treatment. For example, in nasopharyngeal cancer, the anatomical structure of nasopharynx reveals that it is difficult to achieve complete radical resection by surgery, and the effect of radiotherapy for this disease is better than that of surgical treatment. In addition, for early stage non-small cell lung cancer, stereotactic radiotherapy can be chosen if the patient has cardiopulmonary dysfunction and cannot tolerate surgery.