What is a DEXA scan and what does it measure?
DEXA stands for ‘dual energy x-ray absorptiometry’. It is a test that measures the density of bones. In general, the more dense the bone, the stronger it is, and the less likely it is to break. How does a DEXA scan work? A DEXA scan uses low energy x-rays. A machine sends x-rays from two different sources through the bone being tested. Bone blocks a certain amount of the x-rays. The more dense the bone is, the fewer x-rays get through to the detector. By using two different x-ray sources rather than one it greatly improves the accuracy in measuring the bone density. The amount of x-rays that comes through the bone from each of the two x-ray sources is measured by a detector. This information is sent to a computer which calculates a score of the average density of the bone. A low score indicates that the bone is less dense than it should be, some material of the bone has been lost, and is more prone to fracture. How is a DEXA scan done? You lie on your back on a couch and are asked to k
