There are many methods of bone density testing, and the main ones that are commonly used in clinical practice are as follows: the first major category, radiation-based testing methods. This type of method is mainly through a radiation source, emitting rays to a specific site, and determining the density of bone by measuring the degree of absorption of rays by the bone, for example, you can use a single photon to irradiate a specific site, but the accuracy of this method is relatively low, only for epidemiological investigation, screening. The most widely used in clinical practice is the dual-energy X-ray absorption method, which has a very wide range of measurement and high accuracy, and is the mainstream in current clinical practice, while quantitative CT is a category that is under research. The second major category, the detection of bone density by means of ultrasound, this type of bone densitometry is relatively small, the main principle is to use ultrasound to determine the density of bone, but the accuracy is relatively lower than the dual-energy X-ray method.