What do bone scan results tell you?

Hot spot, cold spots: The radiologist looks for evidence of abnormal bone metabolism on the scans. These show up as darker "hot spots" and lighter "cold spots" where the tracers have or haven't accumulated. Although a bone scan is very sensitive to abnormalities in bone metabolism, it's less helpful in determining the exact cause of the abnormality.

Bone metabolism: Bone scan involves intravenous injection of radio tracer usually technetium 99m mdp which accumulates in skeleton. Scan may involve early phase(5-10 min) and late phase(2-3 hr) imaging. Increased uptake is seen in fractures, tumors, infection, etc. Decreased activity is seen in metal artifacts, aggressive tumor/infection, & loss of blood supply to bones. Bone scan very sensitive but not specific.