Bone densitometry may be considered for the following groups: 1, women over 65 years of age and men over 70 years of age with no other risk factors for osteoporosis. 2.Females under 65 years of age and males under 70 years of age with more than 1 risk factor (postmenopause, smoking, excessive alcohol or coffee consumption, lack of physical activity, calcium and vitamin D deficiency in the diet). 3. Those with a history of fragility fracture or family history of fragility fracture. 4.People with low sex hormone level caused by various reasons. 5.X-ray shows osteoporotic changes. 6.People who need to be monitored for efficacy of osteoporosis treatment. 7.Patients with diseases affecting bone mineral metabolism (renal insufficiency, diabetes, chronic liver disease, hyperparathyroidism, etc.) or taking drugs that may affect bone mineral metabolism (such as glucocorticoids, anti-epileptic drugs, heparin, etc.). 8. Pregnant women should have their bone density measured once in each of the 3 and 6 months of pregnancy in order to supplement calcium in a timely manner.