[Basic study of bone mineral density in os calcis by single energy X-ray absorptiometry]

We studied bone mineral density (BMD) in the os calcis by means of single energy X-ray absorptiometry (SXA), and BMD in the third lumbar spine by means of dual energy X-ray absorptiometry (DXA), results were as follows. (1) The doses absorbed in SXA at the exposure site and the opposite site were measured by thermoluminescent dosimetry. The dose absorbed in SXA may be lower than that in DXA. (2) The BMD of the os calcis was measured in 30 female volunteers by SXA and that of the third lumbar spine by DXA, and age, weight, height, and consequences of physical exertion were investigated. BMD as determined by SXA was significantly correlated with that determined by DXA (r = 0.65). BMD as determined by SXA and DXA tended to decrease with age, to increase with height and weight, and to be significantly higher in those who made some physical exertion. In conclusion, SXA may be a useful method for the measurement of BMD.