Tumor size is mainly measured by CT, MRI and other imaging examinations, as well as gastroscopy, laparoscopy, enteroscopy and other endoscopies. Generally, tumors occurring in lymph nodes are measured by the short diameter of the lymph nodes, while some non-lymph node tumor lesions are mainly measured by the long diameter of the tumor lesions. Generally, the size of the tumor is one of the important bases for determining the clinical staging of the patient. In most of the tumor lesions, generally the larger the size of the tumor, the later the clinical staging of the patient. Moreover, the size of the tumor also determines the degree of difficulty for patients to take surgical treatment. Generally, the larger the tumor is, the more difficult the surgical resection treatment will be. Moreover, at present, the effect of anti-tumor treatment is evaluated according to the change of tumor size before and after treatment.