Bone densitometry is a type of imaging examination that measures your bone mineral density, which is a sign of bone strength. Bones that are not very dense become brittle and weak and are more likely to break. A number of conditions cause a loss of bone mass, such as osteoporosis, some inherited diseases or treatments for chronic diseases. During a DEXA scan, density measurements are taken of bones at specific areas of your body. Those measurements then are compared to a database of “normal” individuals of your same age, sex and race. The measurements help determine the presence of osteoporosis and can be used to estimate your risk of bone fracture. If you are being treated for bone loss, a follow-up DEXA scan can show if the therapy is working.
Before your examination, a health care professional will explain the procedure to you and answer any questions you might have. The person who performs the procedure will be a radiographer, also known as a radiologic technologist, a skilled medical professional who has received specialized education in the areas of radiation protection, patient care, radiation exposure, radiographic positioning and radiographic procedures.
The radiographer will ask you several questions about your medical history. It is helpful to have a list of current medications and dosages you are taking. The radiographer also may ask you if you are on hormone replacement therapy or you have had recent medical imaging examinations such as an upper GI series. You will be allowed to remain in your street clothes during the examination. Avoid wearing clothing with metal zippers, buckles, buttons or other metallic objects because they affect the bone density measurement. It is a good idea to wear a comfortable, two-piece outfit such as a sweat suit since you will be lying on your back on an examination table. Avoid taking calcium supplements for 12 hours before your exam because this will affect the reading.
During the Examination
The radiologic technologist will position you on a padded table and ask you to remain as still as possible during the test. The technologist then will use the DEXA equipment to scan one or more areas of bone – usually the lower back, hip or forearm. The DEXA exam does not hurt, and you will not feel anything when the x-rays pass through your body. The exam takes about 15 to 20 minutes.
Post Examination Information
The DEXA scanner computes a numerical reading of bone strength, called a T-score, that is used to compare your bone density with established values. Your physician will receive a report
of the DEXA findings. He or she then will advise you of the results and discuss what further procedures, if any, are needed. If you have low bone density, you may be advised to take calcium supplements or other medication. Your physician also may recommend that you participate in some kind of weight bearing exercise, such as walking, to strengthen your bones.