What Is a DEXA Scan
What is a DEXA scan, and why should you consider having one? A DEXA scan offers a simple yet powerful way to assess your bone density, predict future fractures, and monitor the effectiveness of osteoporosis treatments.
By understanding how a DEXA scan works and what it can reveal about your bone health, you can take proactive steps toward maintaining a strong, healthy skeleton.
What Is a DEXA Scan?
A DEXA scan, or dual-energy X-ray absorptiometry scan, is a medical imaging test used to measure bone density. It is considered the gold standard for diagnosing osteoporosis and assessing fracture risk.
The scan uses low-dose X-rays to calculate the density of your bones and typically focuses on key areas such as the hips, spine, and sometimes the wrist.
The results compare your bone density to established norms to help physicians determine your bone health and detect osteopenia or osteoporosis.
The procedure is non-invasive, painless, and quick. It’s especially recommended for postmenopausal women, aging adults, and individuals with risk factors for bone loss.
How a DEXA Scan Works
During a DEXA scan, two X-ray beams of different energy levels are directed at the bones being assessed, typically the hips, spine, or wrist. The machine calculates the amount of X-ray energy absorbed by the bones and soft tissue separately.
This process allows the system to isolate the bone measurements and provide a precise assessment of bone mineral density (BMD). The dual-energy approach ensures accuracy, even in areas with surrounding soft tissue.
The patient lies on a padded table for the scan while a scanner arm passes over their body. The scan usually takes 10–20 minutes.
The collected data is analyzed to produce a T-score and Z-score, which compare your bone density to healthy individuals and peers of similar age. These scores help physicians determine your bone health and risk of fractures.
DEXA Scan Radiation
A DEXA scan uses a very low dose of ionizing radiation, significantly less than standard X-rays or CT scans. For perspective, the radiation exposure during a DEXA scan is roughly equivalent to the natural background radiation you’re exposed to in a single day.
Because the radiation dose is minimal, the scan is considered safe for most individuals, including those undergoing routine monitoring, and the benefits of identifying bone density issues early far outweigh the minimal radiation risk for most patients.
However, pregnant women should avoid DEXA scans unless absolutely necessary to minimize potential risks to the fetus.
What a DEXA Scan Identifies
A DEXA scan is a diagnostic tool used to evaluate bone health and identify potential issues related to bone density. It plays a vital role in diagnosing and managing conditions like osteoporosis and osteopenia:
• Osteopenia (low bone mass): The scan detects reduced bone density that, while not low enough to qualify as osteoporosis, indicates a higher risk of developing it.
• Osteoporosis: DEXA accurately diagnoses osteoporosis by measuring significant reductions in bone mineral density. This helps identify individuals at increased risk of fractures.
In addition to diagnosing osteopenia and osteoarthritis, a DEXA scan is also often used to:
• Predict the risk of future fractures: By assessing bone strength, the scan helps estimate the likelihood of fractures, particularly in weight-bearing bones such as the hips and spine.
• Monitor treatment effectiveness: For individuals undergoing treatment for osteoporosis, repeated scans over time can show whether medications or lifestyle changes are improving bone density.
DEXA Scan Limitations
While a DEXA scan is an invaluable tool for assessing bone density, it has several limitations:
• Does not assess bone quality: A DEXA scan measures bone mineral density but cannot evaluate bone quality or structural integrity, which are critical for overall bone strength.
• Limited scope of areas scanned: The scan primarily focuses on the hips, spine, and occasionally the wrist. It cannot provide detailed information about other bones unless they are specifically scanned.
• Cannot detect fractures: While the scan predicts fracture risk, it does not identify existing fractures. Other imaging techniques, such as X-rays or MRIs, are needed for this purpose.
• May not identify early bone loss: Subtle or early changes in bone density may not be detected, especially in younger individuals.
• Influenced by external factors: Results can be affected by calcifications, spinal abnormalities, or previous surgeries and potentially lead to less accurate readings.
Who Should Have a DEXA Scan
A DEXA scan is recommended for anyone with an elevated risk of bone loss or fractures. This includes postmenopausal women, especially those over 65 and younger women with risk factors such as a family history of osteoporosis or a history of fractures.
Men over 70 and younger men with risk factors such as low testosterone, previous fractures, or chronic illness should also consider a scan.
Adults with medical conditions that affect bone health, such as rheumatoid arthritis, celiac disease, or chronic kidney disease, may benefit from screening.
Additionally, those on long-term medications such as corticosteroids, chemotherapy, or anticonvulsants, which can contribute to bone loss, are often advised to have a DEXA scan.
The frequency of DEXA scans varies based on individual risk and results. For most people, a scan every 2–5 years is sufficient ifthe results are normal. For those with osteoporosis or undergoing treatment, annual or biennial scans may be recommended to monitor progress.
Central vs. Peripheral DEXA Scan
A central DEXA scan focuses on the spine and hips, which are critical sites for assessing overall bone health and fracture risk.
This type of scan is performed on a large, stationary machine in a clinical setting. It provides the most accurate and comprehensive measurement of bone mineral density (BMD) and is the standard for diagnosing osteoporosis and monitoring treatment effectiveness.
A peripheral DEXA scan measures bone density in smaller bones, such as those in the wrist, forearm, finger, or heel.
These scans are often done with portable devices and are typically used for screening purposes rather than diagnosis. Peripheral scans are less precise and cannot replace central DEXA scans for definitive diagnosis or treatment monitoring.
Herself Health Takes Bone Health Seriously
At Herself Health, we are committed to preventing and managing osteoporosis in Minnesota women aged 65 and over. We’ll help you identify risk factors and develop a personalized plan to keep your bones healthy and strong.
If you already have decreased bone mass, we’ll work with you to implement lifestyle changes that help prevent further bone loss and fractures, whether through dietary adjustments, exercise plans, or medications.
We are currently welcoming new patients at all our office locations. To schedule your appointment, please call 1-888-290-1209 or fill out our Contact page, and we’ll call you to book your appointment.
Risk Factors for Developing Low Bone Mass
Several factors can contribute to the development of low bone mass. Identifying which risk factors apply to you can help you take proactive steps to protect your bone health and prevent fractures. Risk factors include:
• Age (especially over 50).
• Gender (women are at higher risk).
• Family history of osteoporosis or fractures.
• Low body weight or small frame.
• Sedentary lifestyle.
•Poor nutrition, especially low calcium and vitamin D intake.
• Smoking and excessive alcohol consumption.
• Long-term use of certain medications, such as corticosteroids.
• Hormonal imbalances (e.g., low estrogen or testosterone levels).
Medical conditions such as rheumatoid arthritis, celiac disease, and hyperthyroidism.
How To Prepare for a DEXA Scan
A DEXA scan requires no special preparation besides avoiding wearing clothing with metal components.
However, you should inform your healthcare provider about any medical conditions, medications, or prior surgeries that may affect your bone density results. You should also inform the technician if you are pregnant or suspect that you might be pregnant.
It’s important to avoid taking calcium supplements or antacids containing calcium for at least 24 hours before the scan.
What To Wear the Day of Your DEXA Scan
On the day of your DEXA scan, wear loose, comfortable clothing that does not contain metal. Opt for a sports bra, and leave jewelry at home or remove it right before the scan.
You may be asked to change into a gown if necessary, but wearing clothing without metal is the best preparation.
What Not To Do Before a DEXA Scan
To ensure accurate results, refrain from taking calcium supplements or antacids containing calcium for at least 24 hours before the scan. Sometimes, you may be asked to fast for several hours before the test to ensure clear results.
If you’ve recently undergone imaging tests involving contrast dyes or barium, let the technician know, as these may impact the scan's results.
What To Expect During a DEXA Scan
When you arrive for your scan, a technician will explain the process and answer any questions. You’ll be asked to lie down on a padded table, and the technician will position you to ensure that the area being scanned, typically your hips, spine, or wrist, is aligned properly.
During the scan, you will not feel any discomfort. The scanner will pass over your body, emitting a low-dose X-ray from above. You may hear a slight clicking or buzzing noise as the scanner moves, but there is no pain or sensation from the radiation.
It’s important to remain still during the procedure, which usually takes 10–20 minutes. The technician may ask you to hold your breath briefly to ensure the clearest possible images.
You can resume your normal activities immediately following the procedure. The results will be sent to your doctor, who will discuss them with you in detail.
Understanding Your DEXA Scan Results
After your DEXA scan, your results will typically be provided as two key scores: the T-score and the Z-score.
• T-Score: This score compares your bone density to that of a healthy young adult of the same gender. A T-score of -1.0 or higher is considered normal, while a score between -1.0 and -2.5 indicates low bone mass (osteopenia). A score of -2.5 or lower is diagnostic of osteoporosis.
• Z-Score: This score compares your bone density to that of others of the same age, gender, and body size. A Z-score of -2.0 or lower may suggest that factors other than aging, such as an underlying medical condition, are contributing to bone loss.
Your doctor will review these scores alongside other factors, such as your medical history, lifestyle, and risk of fractures, to create a personalized plan for managing your bone health.
What if My DEXA Scan Shows Weakened Bones?
If your DEXA scan reveals osteopenia or osteoporosis, your doctor will work with you to develop a treatment plan to help manage your condition and reduce the risk of fractures. The treatment options can vary based on the severity of bone loss, your overall health, and your risk factors.
• Lifestyle Modifications: This often includes increasing weight-bearing exercise, such as walking, jogging, or strength training, which can help improve bone density. Increasing daily calcium and vitamin D intake may be recommended.
• Medications: Several medications can slow bone loss, promote bone formation, and reduce fracture risk. These include bisphosphonates, denosumab, and selective estrogen receptor modulators (SERMs) such as raloxifene. In more severe cases, anabolic medications such as teriparatide may be prescribed to stimulate new bone growth.
• Hormone Replacement Therapy (HRT): For postmenopausal women, hormone replacement therapy (HRT) may be considered to help maintain bone density, especially when estrogen levels drop.
• Fall Prevention: Since weakened bones increase the risk of fractures, fall prevention strategies are important. This includes making your home safer by removing tripping hazards, installing grab bars, and ensuring good lighting.
• Surgical Intervention: In rare cases where fractures have occurred, or the risk is high, surgical options like vertebroplasty (a procedure to stabilize spinal fractures) may be considered.
Your doctor will guide you through the best treatment options based on your individual situation, and regular follow-up DEXA scans may be recommended to monitor the effectiveness of the treatment.
What Is a DEXA Scan? Key Tool in Assessing Bone Health
Understanding, monitoring, and preserving your bone health is essential for maintaining an active lifestyle, especially as you age. A DEXA scan offers valuable insight into your bone density and can allow you to take action before serious problems arise.
Seeking answers to questions such as, “What is a DEXA scan?” is an important first step, but don’t stop there—make wise lifestyle choices, improve your diet, get plenty of exercise, and follow your doctor’s advice to preserve and even improve bone strength.
Learn more about Herself Health’s unique approach to healthcare for women 65+, and see what a difference patient-focused care can make!