[Use of new osteotropic isotopes in osteoarticular diseases, with special reference to phlogistic arthropathies].

By using an osteotropic complex (99mTc pyrophosphate) scintigraphic and scintiphotographic images were obtained with a view to studying the bone changes in inflammatory arthropathies. In rheumatoid arthritis there is an increase in radioactivity next to affected joints and this phenomenon which seems to contrast with the osteoporosis of the juxta-articular regions is confirmed, since the reduced density that is observed in the radiograms is a result of the lack of equilibrium between bone formation and bone resorption, but only if these two processes are proceeding actively. The "warm" zones, which are very close to the joints, are just as easy to see in relation to inflamed joints as they are in relation to joints in which the inflammation has ceased. Not all the inflamed joints accumulate the radioactive osteotropic complex. The bone changes can occur in cases of chronic inflammatory arthropathies only if the inflammation has been present for at least several months. The images obtained with the polyphosphate correspond to those that can be obtained with other calcium-mimetic and osteotropic isotopes (Sr etc.).