Postoperative radionuclide evaluation of osteoid osteomas.

Five cases of clinically suspected osteoid osteomas were studied by preoperative injection of technetium-99m methylene disphosphonate, intraoperative localization with a radiation-sensitive scintillation probe, and postoperative examination of the entire tissue specimen (including the presumed nidus and surrounding bone). Microradiography and light microscopy were also used. In addition, a new autoradiography technique was introduced in which the excised surgical specimen was placed on undeveloped x-ray film for pathologic localization, diagnosis of the lesions, and a study of the relative intensity of radioactive uptake in the nidus vs. surrounding bone. Autoradiography revealed that the nidus showed the greatest concentration of radioactivity, followed by the surrounding bone. The authors conclude that 99mTc can be used clinically in localizing osteoid osteomas and that preoperative and intraoperative scanning can assist in conservative surgical excision, e.g., minimal extirpation of bone in delicate areas such as the spine. For small lesions, autoradiography assists the pathologist in identifying an osteoid osteoma.