Everything you need to know about a DEXA scan
A bone density test, also known as a DEXA scan or DXA, stands for Dual Energy X-Ray Absorptiometry. DEXA scans are the most widely used test to measure bone mineral density.
This measurement reflects the fact that the denser the bone, the less x-rays pass through it.
Usually, the denser your bone, the stronger it is, and the less likely it is to fracture. (Although this isn’t always the case, as we’ll cover a little further down the page!)
If you’ve ever had an x-ray, the process is very similar.
A DEXA machine uses low-energy x-rays and sends two different sources (thus the ‘D’ for “dual” in the name) through the bone in question. The two x-ray sources double the accuracy in measuring your bone density. So, your bone blocks some of the x-rays. And the more dense your bone is, the less x-rays pass through to the detector.
Then, the amount of x-rays passing through the bone is sent to a computer that calculates an average score for the density of your bone.
A DEXA scan is more accurate than a regular x-ray or CAT scan and requires less radiation exposure. More on this in a moment.
But first, let’s go over the different types of DEXA scans!
- Bone Density Test, Osteoporosis Screening & T-score Interpretation. (n.d.). Retrieved from https://www.nof.org/patients/diagnosis-information/bone-density-examtesting/.
- What Women Need to Know. (n.d.). Retrieved from https://www.nof.org/preventing-fractures/general-facts/what-women-need-to-know/#menopause.
- Demontiero, O., Vidal, C., & Duque, G. (2012). Aging and bone loss: new insights for the clinician. Therapeutic advances in musculoskeletal disease, 4(2), 61–76. doi:10.1177/1759720X11430858
- Stewart, T. L., Ralston, S. H. (2000). Role of genetic factors in the pathogenesis of osteoporosis. J Endocrinol. 166(2), 235e245. doi:10.1677/joe.0.1660235
- Osteoporosis. (n.d.). Retrieved from https://www.nia.nih.gov/health/osteoporosis.
- Kendler, D. L., Kiebzak, G. M., Ambrose C. G., et al. (2006). Effect of calcium tablets on interpretation of lumbar spine DXA scans. Journal of Clinical Densitometry, 9(1), 97–104. doi:10.1016/j.jocd.2005.12.002
- Mettler, F. A., Huda, W., Yoshizumi, T. T., Mahesh, M. (2008). Effective doses in radiology and diagnostic nuclear medicine: a catalog. Radiology 248 (1), 254–263. doi:10.1148/radiol.2481071451
- Briot, K. (2013). DXA parameters: beyond bone mineral density. Joint Bone Spine, 80(3), 265–269. doi:10.1016/j.jbspin.2012.09.025
The only truly accurate way to check your bone density is with a DEXA scan. Regular x-rays will not give you the details (T-score and Z-score) your doctor needs to make an accurate diagnosis.
DEXA (or DXA) stands for Dual Energy X-Ray Absorptiometry. There are two types: Central and Peripheral. The first covers your entire skeleton; the second focuses on your extremities, such as your hands or feet.
In the US, Medicare covers the cost of your DEXA scan every two years. If you need more scans, please check with your insurance provider for complete coverage details.
In Canada, the Federal Government says that if you’re 65 and never had a DEXA, Canadian Medicare will cover it. They’ll also let you do follow-up DEXAs if you need them, every 2 years and cover them. Sometimes, if your treatments are annual, Medicare will cover the cost.
What if you’re under 65? Most commercial providers will cover your initial DEXA if you’re post-menopausal and you have risk factors (such as smoking, genetics, or being under- or overweight.)
If your health insurance does not cover the cost of your DEXA scan, you will have to pay out of pocket.
Below is a directory of clinics that offer DEXA scans in Canada:
Vancouver, British Columbia
Vancouver, British Columbia, Canada
Mobile DEXA scans and body composition imaging in the Vancouver British Columbia area
Vancouver DEXA Scan
Unit 107, 16028 – 100A Ave. NW
Edmonton, AB T5P 0M1
Medisys Montreal + (Medisys has other locations in Canada)
Suite 203 6100 Ave. Du Boise
Montreal, Quebec H3S2W1
Below is a directory of clinics that offer DEXA scans in the United States:
- Albuquerque, NM
- Atlanta, GA
- Austin, TX
- Boston, MA
- Bloomington, IL
- Charlotte, NC
- Chicago, IL
- Dallas, TX
- Washington, DC
- Detroit, MI
- Dupage, IL
- Folsom, CA
- Highland Park, IL
- Houston, TX
- Kansas City, KS
- Las Vegas, NV
- Long Island, NY
- Madison, MS
- Madison, WI
- Minneapolis, MN
- Missouri, MO
- New Orleans, LA
- Gurnee, IL
- Orange County, CA
- Orlando, FL
- Pensacola, FL
- Philadelphia, PA
- Sacramento, CA
- San Carlos, CA
- San Diego, CA
- San Francisco, CA
- Seattle, WA
- Syracuse, NY
New York, NY
Lenox Hill Radiology
525 Park Avenue @ 61st Street
New York, NY 10065
Phone: (212)-888-1000 (prompt 3)
More coming soon, if you would like to see your DEXA scan clinic listed here please contact us.
Once you reach one of the milestones listed below, you should have a DEXA scan every 2 years:
- You are a woman 65 or older
- You are a postmenopausal woman under 65
- You are a man 70 or older
- You are 50 or older and recently suffered a bone fracture, especially from a minor fall
I have a metal plate/object in my body (head, arm, leg etc.), is it still safe/effective to have a body composition scan?
Yes. Since the metal object will be present in both initial and future scans, the readings will still be helpful since there is no change in the object. The metal will not greatly affect readings. A DEXA scan’s beams can’t interact with the metal object like an MRI machine’s will, so while the surrounding tissue will be classified incorrectly as bone, readings will still be consistent from scan to scan.