Bone is one of the most common metastatic sites of malignant tumors, and most of them are multiple bone metastases. Lung cancer can also metastasize to bones, among which bone metastasis caused by lung adenocarcinoma is more common. Bone metastasis examination methods: 1) PET-CT, which is often called PET; 2) ECT, which is usually called bone scan; both of these examination methods can detect whether bone metastasis has occurred in a timely and accurate manner, and PET-CT (PET) is better than ECT (bone scan) for the diagnosis of bone metastasis, but because PET is expensive, bone scan is usually used to detect bone metastasis, and bone scan can also determine whether bone metastasis is very accurate. However, because of the high cost of PET, bone scan is usually used.