The simplest way to determine whether lung cancer metastasis is clinically non-existent can be diagnosed comprehensively by PET-CT, abdominal ultrasound, bone scan and CT, MRI and other examinations. 1. PET-CT examination: whether lung cancer is metastatic or not can be assessed by PET-CT examination with whole-body scanning, which can evaluate the whole-body parts such as brain, liver, bone and adrenal gland. 2. Abdominal ultrasonography: whether lung cancer has metastasized or not can be examined by abdominal ultrasonography, which can check whether there are lumps and other abnormalities in the liver, and make a comprehensive diagnosis of whether there is liver metastasis. 3. Bone scanning and CT examination: whether lung cancer has metastasis can be examined by bone scanning and CT examination to see whether there are localized lumps and so on, so as to comprehensively evaluate whether there is bone metastasis. 4. MRI: metastasis in brain, liver, adrenal gland and soft tissues can be detected through MRI examination. To determine whether lung cancer has metastasized, it is necessary to improve relevant examinations under doctor’s guidance to comprehensively diagnose and determine whether metastasis has occurred, and listen to doctor’s advice to actively carry out scientific and reasonable treatment to control the development of the disease.