A DEXA bone density study, or Dual X-ray absorptiometry, is a medical testing procedure used to measure bone mineral density, according to WebMD. The procedure is non-invasive and exposes the patient to a minimal amount of radiation.
A DEXA bone density test checks an individual’s bone strength, and is used to diagnose osteoporosis and other conditions that cause the bones to become thinner and fragile, explains the Radiological Society of North America. It is performed with the patient lying on a table while the scanner is aimed at them. It is usually aimed at the hips or spine, but sometimes other areas of the body may be scanned. The scanner produces two X-ray beams of very low-energy radiation and measures the amount of X-rays that passes through the bone, which is dependent upon how thick the bone is, notes WebMD. A final measurement is determined based on the difference between the two beams.
A radiologist analyzes and interprets the results in the form of a T score or Z score, states RSNA. The T score shows how much bone the patient has compared with a young adult of like gender and maximum bone density. Z score shows the amount of a patient’s bone as compared to people of similar age, size and gender.