Radiographic absorptiometry in the diagnosis of osteoporosis

Radiographic absorptiometry (RA) is a technique for bone mass measurement from radiographs of peripheral sites, most commonly the hand or heel. The principle was first described in 1939, and RA became relatively widely used as a research technique in the 1960s, although interest in RA subsequently dwindled as precise nonradiographic densitometry techniques became available. Recently, however, computerized image processing has been applied to radiography, with the result that current RA techniques applicable to a routine clinical setting are as precise and accurate as dual-energy or single-energy x-ray absorptiometry (DXA or SXA). In addition, recent studies demonstrate that the strength of association between low bone mass measured by RA and fracture risk is comparable to that for other forms of bone mass measurement. The relatively low cost and lack of need for specialized equipment make RA a highly attractive option for the diagnosis of osteoporosis that is available to specialist and nonspecialist physicians alike.