Bone Density Scan (Dexa)

Nuclear bone scans are not to be confused with the completely different test often termed a "bone density scan," DEXA or DXA, which is a low exposure X-ray test measuring bone density to look for osteoporosis and other diseases where bones lose mass, without any bone re-building activity. The nuclear medicine scan technique is sensitive to areas of unusual bone re-building activity because the radiopharmaceutical is taken up by osteoblast cells which build bone. The technique therefore is sensitive to fractures and bone reaction to infections and bone tumors, including tumor metastases to bones, because all these pathologies trigger bone osteoblast activity. The bone scan is not sensitive to osteoporosis or multiple myeloma in bones, and therefore other techniques must be used to assess bone abnormalities from these diseases.