99MTc pyrophosphate has restored bone scintigraphy to the position of respectability it had lost with radiostrontium 85 and 87m, and it has rapidly become the method of choice for the detection of osteogenic hyperactivity. In cases of tumor the histologic disorder is frequently detected prior to the morphologic changes seen in X-ray pictures. The biophysical properties of 99mTc pyrophosphate provide high quality imaging of the skeleton. The scans or scintiphotos render possible a more sensitive and earlier diagnosis than radiography, though bone scanning does not of course supersede radiography. The two methods are complementary. In present day oncologic practice, however, bone scintigraphy with 99mTc pyrophosphate replaces to advantage the conventional radiographic "bone survey". In neurology the change is already appreciable and has proved its worth. In the light of results in 78 neurologic patients attention is drawn to the significant changes bone scintigraphy has brought about in diagnosis and therapeutic planning. The indications which have already emerged from this new method of nuclear neurology are tabulated, discussed and illustrated.