The only curative approach for osteoid osteoma is operative removal of
the nidus, but intraoperative detection of the nidus is difficult eve
n when an X-ray amplifier is used. A simple probe-guided operative pro
cedure using technetium-99m methylene diphosphonate is described, and
the results and follow-up in 12 patients are reported. In addition phy
sical properties of the probe have been evaluated by phantom measureme
nts.