[Bone mineral estimation (Hydroxyl apatite equivalent) by direct measurement of photo absorption in the upper extremity (phalanges, radius and ulna) (author's transl)].

The x-ray source of the apparatus developed by the authors for bone mineral estimations consists of a small anode tube with a silver anode. The value of the procedure has been tested by in vitro and in vivo experiments. The in vitro measurements were carried out on a bone reference system consisting of a model bone (Reiss) as well as on a macerated tibia embedded in a resin (Heuck). The results were compared with the values obtained by Rassow. It has been shown that the artificial resin is of only limited value as a connective tissue equivalent. The method of mineral estimation using phalanges is described and its reproducibility was tested on 17 parameters. The absorption coefficient of the spongiosa proved to be particularly critical. Finally, measurements, using the forearm, by Cameron's method are discussed briefly.