Medical imaging plays an essential role in diagnosing a wide range of health conditions. Among the most common tests involving bones are the bone density scan (also known as a DEXA or BMD scan) and the standard X-ray.
While both scans produce images of your skeletal system, at the end of the day what’s important to take away is that they serve very different medical purposes while appearing fairly similar on the surface.
What Is a Bone Density Scan (DEXA)?
A bone density scan is a specialised imaging test designed to measure the strength and mineral content of your bones. It’s most used to detect conditions such as osteopenia or osteoporosis, which lead to weakened bones and an increased risk of fractures. The scan is performed using a low-dose X-ray technique called dual-energy X-ray absorptiometry (DEXA).
Bone density scans are most often recommended for people who are considered at higher risk of bone loss. These include postmenopausal women, individuals over the age of 65, and patients who have been on long-term corticosteroid therapy. Those with a family history of osteoporosis or a history of bone fractures may also be advised to undergo this test.
What Is a General X-Ray?
A standard X-ray is one of the most frequently used diagnostic tools in medicine. It captures images of bones and certain internal organs using a controlled burst of electromagnetic radiation. X-rays are often ordered to identify fractures, detect infections, or assess bone damage due to conditions like arthritis or cancer.
They are also widely used in lung imaging, for example, in chest X-rays that help diagnose pneumonia, tuberculosis, or heart failure. Unlike a DEXA scan, a regular X-ray does not measure bone density. While it can show advanced bone thinning or severe fractures, it lacks the sensitivity to detect early signs of mineral loss in the bones.
Key Differences Between Bone Density Scans and X-Rays
The main difference lies in the purpose and precision of each test. A bone density scan is a preventative screening tool. It is highly accurate for measuring subtle changes in bone mineral content, which is crucial for diagnosing osteoporosis before it leads to fractures.
In contrast, a general X-ray is often reactive in nature meaning it’s used after symptoms, or an injury appear to confirm a diagnosis or track healing.
Radiation dose
Another major difference is radiation exposure dose. Bone density scans emit a very low dose of radiation, in fact the dose of radiation received from a BMD scan is typically less than a day of natural background radiation much lower than that of a standard X-ray. This makes DEXA scans particularly safe for routine screening, even in older adults who may need repeated testing over time.
Scan Time
In terms of scan time, a DEXA takes about 10 to 20 minutes, while most X-rays are completed in a matter of minutes, depending on how many images are needed.
Where to Book Your Scan
If you’ve been advised to get a bone density scan or X-ray, Bergman Ross offers patient-friendly care, expert imaging, and fast, accurate results, so you can take the next step in your health journey with confidence.