What is it?

A bone scan is sometimes performed to rule out an inflammatory process (such as a tumor or infection) or an occult fracture (small fracture not seen on an x-ray).

A bone scan is performed by injecting a small amount of radioactive marker into an intravenous line (IV). Three hours later the patient is placed through a scanner and the radioactive marker will be concentrated in any region where there is high bone turnover.

A bone scan is a highly sensitive test to pick up tumors, infections, or very small fractures because these conditions all result in high bone turnover. It can also be used to determine if a compression fracture of the vertebral body is old or new, as an old fracture will not light up and a new one will.

Bone scans, however, cannot distinguish what a lesion represents, and therefore cannot differentiate between a tumor, an infection or a fracture. Therefore, this type of imaging study usually needs to be followed by a CT scan and/or MRI scan to better characterize the lesion.

The results of the test reveal 'hot' and 'cold' spots. Hot spots appear darker on the image and denote an area of high tracer uptake, possibly indicating an abnormality (e.g. infection). Cold spots appear light and indicate the bone absorbed less of the tracing element.