DEXA Scan: What It Is, Who Needs It & Results Explained

Understanding the Mind–Body Connection

A DEXA Scan (Dual-Energy X-ray Absorptiometry) is a fast, painless, low-radiation imaging test that measures bone mineral density (BMD). It is the gold-standard diagnostic tool to detect osteoporosis, low bone mass (osteopenia), and predict fracture risk — typically completed in just 10–20 minutes.

Scan Duration: 10–20 min

Radiation Dose: Very Low

Injections / Prep: None

Primary Sites: Spine & Hip

1. What is a DEXA Scan?

DEXA stands for Dual-Energy X-ray Absorptiometry. It uses two low-dose X-ray beams at different energy levels to measure how dense your bones are. The denser your bones, the stronger and less fracture-prone they are. The DEXA scanner calculates the amount of X-ray energy absorbed by bone versus soft tissue, producing a precise Bone Mineral Density (BMD) score.

It is most commonly performed on the lumbar spine (lower back) and hip, as these are the sites most vulnerable to osteoporotic fractures. In some cases, the forearm or total body may also be scanned.

Unlike a traditional X-ray that only shows fractures after they occur, a DEXA Scan catches silent bone loss years before a fracture happens — making it a powerful preventive tool.

2. Why is a DEXA Scan Important?

Osteoporosis is often called the “silent disease” because bone loss happens gradually — with no pain, no warning signs — until a fracture occurs. In India alone, over 50 million people are affected by osteoporosis, yet a vast majority remain undiagnosed.

A DEXA Scan is critical because it:

Detects low bone density before a fracture occurs
Monitors the effectiveness of osteoporosis treatment over time
Assesses fracture risk so your doctor can take preventive action
Identifies candidates who benefit most from lifestyle changes or medication
Helps guide decisions around joint replacement and orthopaedic surgery

3. Who Should Get a DEXA Scan?

The following individuals are strongly recommended to undergo a DEXA Scan:

Women aged 65 and above (routine screening)
Men aged 70 and above
Postmenopausal women under 65 with risk factors (family history, low body weight, smoking)
Anyone who has broken a bone after age 50 from minor trauma
Patients on long-term steroid or corticosteroid therapy
Individuals with rheumatoid arthritis, thyroid disorders, or vitamin D deficiency
Patients being considered for knee or hip replacement surgery
Anyone with a BMI below 19 or significant height loss

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4. How is the DEXA Scan Performed?

The procedure is remarkably straightforward and entirely non-invasive:

i. Preparation: No fasting required. You may be asked to avoid calcium supplements 24 hours before the scan. Wear comfortable, metal-free clothing.

ii. Positioning: You lie flat on a padded table. The scanner arm passes slowly over your body — you remain completely still but do not enter a tunnel or enclosed space.

iii. Scanning: The machine emits two low-energy X-ray beams that measure bone density at key sites — typically the lumbar spine and hip. The dose is extremely small, roughly equivalent to a few hours of natural background radiation.

iv. Results: The scan produces a T-score and Z-score, which are interpreted by your orthopaedic specialist.

5. Understanding Your DEXA Scan Results: T-Score Explained

Your result is given as a T-score — a comparison of your bone density to that of a healthy young adult. Here is how to interpret it:

T-Score Range	Diagnosis	What It Means	Status
-1.0 and above	Normal	Healthy bone density	Normal
-1.0 to -2.5	Osteopenia	Low bone mass; monitor and act early	Monitor
-2.5 and below	Osteoporosis	High fracture risk; treatment needed	High Risk

Your doctor will also review your Z-score, which compares your bone density to others of the same age and gender — particularly useful for younger patients and to identify secondary causes of bone loss.

6. DEXA Scan and Joint Replacement Surgery

At Fathima Multispeciality Hospital, a DEXA Scan is a vital part of pre-surgical assessment for patients undergoing knee or hip replacement surgery. Bone quality directly affects how well an implant integrates, the risk of periprosthetic fractures, and long-term surgical outcomes.

Dr. Sukesh Reddy P, who leads our orthopaedic department, uses DEXA results to personalise surgical planning — including implant selection, bone augmentation decisions, and post-operative rehabilitation protocols. This is especially important for our advanced Robotic Knee Replacement procedures, where bone quality data contributes to the precision planning algorithms.

7. How Often Should You Repeat a DEXA Scan?

The frequency depends on your initial result and clinical risk:

Normal bone density: Repeat every 2–5 years
Osteopenia: Repeat every 1–2 years
On osteoporosis treatment: Repeat every 1–2 years to track response
After fracture or new risk factors: As advised by your orthopaedic doctor

Frequently Asked Questions (FAQ’s)

1Q: What is a DEXA Scan?
Ans: A DEXA Scan is a painless, low-radiation test that measures bone mineral density to detect osteoporosis and fracture risk in 10–20 minutes.

2Q: What is a normal DEXA Scan T-score?
Ans: A T-score above -1.0 is normal. Between -1.0 and -2.5 is osteopenia. Below -2.5 indicates osteoporosis.