While both a bone scan and a DEXA (Dual-Energy X-ray Absorptiometry) scan are valuable diagnostic tools in assessing bone health, they serve different purposes and employ distinct technologies. A bone scan is a nuclear imaging test primarily used to identify bone diseases and abnormalities such as fractures, infections, or cancers. It involves the injection of a small amount of radioactive material, which concentrates in areas of high bone activity, making them visible on the scan. This can highlight a range of bone conditions but it does not quantify bone density. On the other hand, a DEXA scan specifically measures bone mineral density, using low-dose X-rays to calculate the concentration of calcium and other bone minerals. This makes it the gold standard for diagnosing osteoporosis and osteopenia by providing precise measurements of bone density, rather than highlighting abnormalities. Essentially, a DEXA scan evaluates the risk of developing bone diseases by measuring bone loss, whereas a bone scan detects existing abnormalities in bone metabolism or structure.