Fig. 25.26 Bone mineral densitometry measurement of the lumbar spine using Dual Energy X-ray Absorptiometry. The method is based on measurement of the radiation transmission of two separate X-ray energies through a medium consisting primarily of two different materials, bone and soft tissue. The total bone mineral content of L2ΓÇôL4 is measured in grams of hydroxyapatite equivalent (gHA) and expressed as gHA/cm2. The normal range depends on age, sex, weight and ethnic origin. Bone mineral measurements from the lumbar spine, femoral neck and radius are used to assess the bone mass and predict the risk of fractures at these sites.
