In recent years, the incidence of cancer has continued to increase and has now become 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 (about 20% of bone metastasis patients do not have bone pain), which is usually confined, progressively aggravated, and particularly severe at night. Patients often suffer from unbearable pain, insomnia, loss of appetite, etc., and even develop pathological fractures or paraplegia and other complications, which seriously affect the quality of life of patients. It is found that about 70% to 85% of the deaths due to malignant tumors are found to have bone metastases at autopsy. The primary tumors that are 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 is very important. ECT whole-body bone scan has become the most effective, simple, fastest and commonly used means for clinical examination of tumor bone metastasis and follow-up. In foreign countries, it is a routine examination program for cancer patients. Although there are many ways to examine bone lesions, such as X-ray, CT, MR, etc., only ECT whole-body bone scan can complete the whole-body bone examination in one scan. Bone scanning has high sensitivity, and it is generally believed that bone metastases of tumors can be detected more than half a year earlier than X-ray examination. In addition to early detection of bone metastasis, bone scan is mainly used for follow-up, staging, efficacy monitoring and prognosis judgment of tumor patients. Research shows that about 20% to 30% of cancer patients have new bone metastases in the first 3-4 years. Overseas literature reports that within 4 years, about 7% of stage I patients, 25% of stage II patients and 58% of stage III patients with breast cancer have their bone scans changed from normal to positive. Therefore, cancer patients, especially breast cancer, lung cancer, prostate cancer and other cancers that are prone to bone metastasis, should undergo bone scanning before operation, which can not only provide important information for the selection of treatment plan, but also help doctors to choose more appropriate treatment plan, and also serve as the basis for the comparison of the follow-up in the future; bone scanning should also be carried out on a regular basis for the follow-up examination after operation, and in general, bone scanning should be carried out once every half a year in the first 2 years after operation; in 2 years, bone scanning should be carried out once every 6 months; and in 2 years, bone scanning should be carried out regularly. Generally speaking, in the first 2 years after surgery, bone scan should be carried out every half a year; after 2 years, asymptomatic patients should be followed up once a year, and the follow-up of symptomatic patients should be increased according to the doctor’s instructions.