What is a DEXA Scan? Understanding Bone Mineral Density Testing

Osteoporosis is often called the "silent thief." Learn how a quick, painless DEXA scan at Frontier Diagnostics measures your bone strength and helps prevent future fractures.

You might go for a walk to strengthen your heart or solve puzzles to keep your brain sharp. But how often do you think about the health of your bones?

Osteoporosis is often called the "silent thief" because it steals bone mass without any symptoms—until you suffer a fracture from a minor fall. For many patients in Ontario, a broken wrist or hip is the first sign that something is wrong.

At Frontier Diagnostics in Guelph, we believe in prevention over reaction. The best tool we have to catch bone loss early is the DEXA scan (Dual-Energy X-ray Absorptiometry), also known as a Bone Mineral Density (BMD) test.

Here is everything you need to know about this "Gold Standard" test and why it is one of the easiest exams you will ever take.

What Exactly is a DEXA Scan?

A DEXA scan is a specialized type of X-ray that measures the amount of calcium and other minerals in your bones. The result tells us how dense (strong) your bones are.

While standard X-rays are great for seeing a broken bone, they aren't sensitive enough to detect bone loss.

A DEXA scan, however, is incredibly precise. It can detect even small changes in bone density, allowing your doctor to treat you before a fracture occurs.

What Happens During the Appointment?

If you are claustrophobic or dislike medical tests, you will love the DEXA scan. It is widely considered the easiest and most comfortable exam in diagnostic imaging.

No Tunnels: The machine is completely open. You lie flat on a padded table while a scanning arm passes over you.
Stay Dressed: In many cases, you can remain in your own clothes, provided they don't have metal zippers, buttons, or snaps (sweatpants and a t-shirt are perfect!).
It is Fast: The whole process usually takes 10 to 20 minutes.
It scans specific areas: We typically scan your lumbar spine (lower back) and your hips, as these are the areas most prone to fracture.

Is it Safe? (The Radiation Question)

Patients often ask us about radiation safety. A DEXA scan uses a very low dose of X-rays—much lower than a standard chest X-ray or a CT scan.

To put it in perspective: the amount of radiation you receive from a bone density scan is roughly equivalent to the natural background radiation you are exposed to during a standard flight across Canada. It is considered very safe.

Who Should Get a Bone Density Scan?

In Ontario, guidelines generally recommend screening for:

Women and men age 65 and older.
Post-menopausal women with risk factors (such as smoking or a family history of hip fractures).
Anyone who has broken a bone from a minor fall (a "fragility fracture").
Individuals taking medications that weaken bones (such as long-term steroid use like Prednisone).

Note: Consult your doctor to see if you qualify for an OHIP-covered scan based on your specific medical history.

Understanding Your Results: The "T-Score"

After your scan at Frontier Diagnostics, our radiologists will analyze the images and assign you a "T-Score." This number compares your bone density to that of a healthy young adult.

T-Score of -1.0 or higher: Normal bone density.
T-Score between -1.0 and -2.5: Low bone mass (Osteopenia). This is a warning zone where you may need lifestyle changes to prevent further loss.
T-Score of -2.5 or lower: Osteoporosis. This indicates your bones are fragile, and your doctor may recommend treatment to prevent fractures.

How to Prepare

Preparation is simple, but there is one crucial rule:

Do not take calcium supplements or multivitamins for 24 hours before your exam. Undissolved calcium tablets in your stomach can block the X-rays and skew your spine results. Otherwise, you may eat and drink normally!

Protect Your Future Mobility

Strong bones are the foundation of an active, independent life. If you are over 65 or have concerns about your bone health, talk to your doctor about a requisition for a Bone Mineral Density test.

Frontier Diagnostics is proud to offer state-of-the-art bone density scanning right here in Guelph.

This blog is for general information only and isn’t intended to be medical advice. Please consult a healthcare provider for any questions or concerns about your own health.