In recent years, the incidence of cancer has continued to increase and is now one of the most common causes of death. The common distant metastasis of cancer is bone metastasis, and pain is the most common clinical symptom of bone metastasis (also about 20% of patients with bone metastasis have no clinical symptoms of bone pain), and this pain is usually limited and progressively aggravated, especially at night. Patients are often tormented by unbearable pain, insomnia and loss of appetite, and even develop complications such as pathological fracture or paraplegia, which seriously affects the quality of life of patients. It is found that about 70% to 85% of the cases who died due to malignant tumors were found to have bone metastases during autopsy. The primary tumors most prone to bone metastasis include breast cancer, lung cancer, prostate cancer, gastric cancer, thyroid cancer, rectal cancer, neuroblastoma and so on. Therefore, early diagnosis of tumor bone metastasis becomes very important. ECT whole-body bone scan has become the most effective, easy, fast and commonly used means for clinical examination of tumor bone metastasis and follow-up. In foreign countries, it is a routine examination for cancer patients. Although there are many methods to examine skeletal lesions, such as X-ray, CT, MR, etc., only ECT whole-body bone scan can complete the examination of whole-body bones in one scan. Bone scan has high sensitivity and is generally believed to detect bone metastases more than half a year earlier than X-ray examination. In addition to early detection of bone metastases, bone scan is also used for follow-up, staging, efficacy monitoring and prognosis of tumor patients. Studies have shown that about 20%-30% of cancer patients have new bone metastases in the first 3-4 years. Foreign literature reports that about 7% of stage I patients, 25% of stage II patients, and 58% of stage III patients have positive bone scans within 4 years of breast cancer. Therefore, cancer patients, especially those who are prone to bone metastasis such as breast cancer, lung cancer and prostate cancer, should undergo bone scan before surgery, which not only provides important information for the selection of treatment plan and helps doctors to choose a more appropriate treatment plan, but also serves as a basis for follow-up comparison in the future; after surgery, bone scan follow-up examination should be performed regularly, generally speaking, it should be performed every six months during the first two years after surgery. After 2 years, asymptomatic patients should be followed up once a year, and those with symptoms should be followed up according to medical advice.