[Spinal biphotonic absorptiometry].

Spinal biphotonic absorptiometry allows a quantitative investigation of bone mineralisation. The study of a control and an osteoporotic population allowed the definition of the fracture threshold independent of age and the curve of the variation in the mineral content with aging. A good correlation was observed with computed tomography. The criteria of definition of a population at risk for the purposes of a longitudinal study are proposed. Biphotonic absorptiometry is an excellent examination for the detection of demineralisation and for the monitoring of treated subjects.