Scanning site: forearm (distal ulna, 1/3 of the bone) fan X-beam digital detector Adult calculation parameters: BMD, BMC, Area, T-value, Z- value, BOI, RRF, age-ratio, adult-ratio, physiological age of bones, EOA, BMI index. Calculation parameters for children: BMD, Z value, age- ratio, BMI index, physiological age of bones, height prediction. Cone beam scanning, surface imaging technology, fast imaging speed, good uniformity of image gray value