Paget's disease. Radiological changes occurring in untreated patients and those on therapy with salmon calcitonin during two years' observation.

Radiological observations over two years were made in 23 patients with Paget's disease. Radiological criteria for progression and regression of disease are defined. Fourteen of the patients were treated with salmon calcitonin. Of these treated patients four showed regression of the disease and only two showed progression, both in the skull vault. Of the remaining nine untreated patients none showed regression but two showed progression. The radiological findings confirm that calcitonin will prevent the extension and sometimes induce healing of Paget's disease in long bones but that the skull appears to respond differently. Radiological changes were slow to occur and yearly or two yearly follow up is sufficient.