Associate Professor of Nuclear Medicine Shohada-e Tajrish Hospital, Shahid Beheshti Medical University of Sciences
Bone scintigraphy with technetium-99m– labeled diphosphonates is one of the most frequently performed in Nuclear Medicine Departments. Whole body bone scintigraphy is
not specific, but its excellent sensitivity makes it useful in screening for many pathologic conditions in a single examination. Moreover, some conditions that are not clearly depicted
on anatomic images can be diagnosed with bone scintigraphy.
Bone metastases typically appear as multiple foci of increased activity randomly scattered prominently throughout the axial skeleton, although they occasionally manifest as a single lesion or areas of decreased uptake. Bone scintigraphy is also useful for evaluating disease extension and their malignant changes in polyostotic benign tumors as exostosis and in Paget disease.
Tri-phasic bone study is carried out immediately after radiotracer injection and imaging of perfusion, blood pool and delayed bone uptake. A combination of focal hyperperfusion, focal hyperemia, and focally increased bone uptake is virtually diagnostic for acute osteomyelitis in patients with nonviolated bone. Traumatic processes can often be detected, even when radiographic findings are negative. Most fractures are scintigraphically detectable within 24 hours, although in elderly patients with osteopenia, further imaging at a later time is sometimes indicated. Athletic individuals are prone to musculoskeletal trauma, and radionuclide bone imaging is useful for identifying pathologic conditions such as plantar fasciitis, stress or occult fractures, “shin splints,” and spondylolysis, for which radiographs may be nondiagnostic. Bone scintigraphy could reveal avascular necrosis in patients with negative radiographs. Aging of vertebral compression fracture and battered child syndrome and are important entities for patient management and in forensic medicine. Radionuclide bone imaging will likely remain a popular and important imaging modality for years to come.