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A Comprehensive Guide To Bone Density Scans

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What is a bone density scan, and when do you need to start worrying about the health of your bones?

As a young adult, your bones are strong. But as you age, particularly women, you lose bone mass, making it easier to break bones. If you have a family history of osteoporosis or are worried you might be losing height, consider booking a bone density scan.

This guide will tell you everything you need to know about what to expect at your scan, what it costs, and how to read the results.

  1. What are Bone Density Scans, and what do they reveal?
  2. Why do you need to test your bone density?
  3. How accurate are bone density scans?
  4. 4 warning signs of osteoporosis
  5. When do doctors recommend a bone density scan 
  6. What does a bone density scan cost? 
  7. How to prepare?
  8. What to expect during and after your scan? 
  9. How to read a bone density scan and results
  10. Bone density charts by age
  11. Where to get the test done
  12. How to check bone density at home 
  13. How often should you have a bone density scan?

What are Bone Density Scans, and what do they reveal?

Bone Density Scans are a pain-free, non-invasive imaging test that measures bone mineral density — how much calcium is contained in a bone segment. We use bone density scans to diagnose osteoporosis and osteopenia. The most common areas we evaluate are the hip and lumbar spine.

Why do you need to test your bone density?

As you age, your bone density decreases, and your risk of breaking bones increases. A young person can slip and fall and walk away with bruises. The same fall can cause senior citizens to fracture or shatter their bones.

Bone density scans reveal the strength of your bones and degeneration between vertebrae in the spinal column. It can help doctors diagnose osteoporosis, prescribe a treatment plan and monitor its effectiveness. 

How accurate are bone density scans?

It depends on the type of scan used. 

  1. Quantitative computed tomography (QCT)
  2. Dual x-ray absorptiometry (DXA)

According to a study by the International Journal of Endocrinology [1], QCT scans detected osteoporosis in 46.6% of cases. In comparison, DXA only saw degeneration in 17% of cases.

At ERAD, we use QCT densitometry to measure the amount of calcium and other minerals in your bones. It’s a three-dimensional technique for quantifying volumetric trabecular bone density that’s not affected by abnormal aortic calcification and spine degeneration. It uses a CT scanner and produces a 3D image (as shown below).

4 warning signs of osteoporosis

  1. You struggle to stand upright. Instead, you’re starting to stoop.
  2. You’ve noticed that you’re losing height – over 3,5 cm: this could indicate compression fractures in your spine.
  3. You frequently suffer from back pain.
  4. You’re experienced many broken bones or fractures in quick succession. 

When do doctors recommend a bone density scan 

If you’re experiencing any of the above symptoms of osteoporosis, it’s time to speak to your doctor about arranging a bone density scan. 

If you’re not experiencing early warning signs, do you still need to get scanned? Your doctor may recommend a bone density scan if:

  • You’re a woman over the age of 65
  • You’re postmenopausal and have a high risk of osteoporosis
  • You have a family history of osteoporosis
  • You’re a woman receiving hormone replacement therapy
  • You take medications that increase your risk of osteoporosis

Why do doctors recommend that women get bone density tests at a younger age than men?

According to research, women tend to lose bone density mass well before men of the same age. You also lose bone mass faster. This is why doctors typically recommend that women are scanned for osteoporosis far younger than men.

What does a bone density scan cost? 

Let me ask you this first, will you be paying for your scan privately or through your medical aid?

For private cash payments, the cost depends on the clinic conducting the scan. Usually, if you pay the amount in full, you’ll receive a small discount. You’re well within your right to ask for a discount.

For medical aid members, most medical aids cover the cost of a bone density scan. You’ll need pre-authorisation before the scan. If there is a shortfall, it will be nominal. 

If you have your bone density scan at an ERAD clinic in Namibia, here are the costs:

  • Medical Aid Rates: N$2,334.03*
  • Private Rates: N$2,101.93 **

* If the patient has used/depleted their medical aid radiology benefits, then they will need to cover the shortfall between existing benefits and the price of the Bone Density Scan.

** Rates for non-medical aid patients.

How to prepare?

Once you’ve booked your scan, the clinic will be in touch to help you prepare for the day. We ask that you arrive 15 minutes before your appointment to complete any forms.

Can I eat before a bone scan?

For bone density scans, you can still eat normally unless instructed otherwise. But you will be asked to hold off on taking your calcium supplements 24 hours before your appointment.

What can I wear for my bone scan?

Most clinics will ask you to change into a hospital gown before your scan, but if not, we ask that you wear loose, comfortable clothing rather than tight-fitting items.

Please avoid clothing with zippers, grommets, buttons or other metal embellishments. Stick to casual wear or sweatsuits.

Do I need to inform the doctor of any medical procedures prior to my bone scan?

If you’ve had an MRI or CT scan within the last seven days and the radiologist administered a radioisotope injection, barium study, or intravenous contrast material, please inform your doctor or the clinic. It may be best to postpone the scan. 

What to expect during and after your scan? 

Once you’re prepped and ready, a nursing sister will take you to the radiologist to begin your procedure. You’ll be asked to lie on your back on a flat table. A scanner will then pass over the top of you and take images. 

The procedure takes less than 30 minutes, and you can go home immediately.

Those images are then given to our resident radiologist to analyse and compile a report for your doctor. 

At ERAD, your test results are ready within 2 hours. You can download them directly from the portal or contact your doctor to discuss the findings. 

What if my test reveals I have osteoporosis?

If we discover signs of osteoporosis, your doctor may request a follow-up scan. Our team will scan your hip and spine during this procedure to confirm the diagnosis.

How to read a bone density scan

Your doctor will discuss your results with you, but if you’d like to review the scans, here’s what you need to know.

The test aims to determine your BMD or bone mineral density. To determine this, we compare your results to a T-score (a young, healthy adult) and a Z-score (an adult of a similar age to you).

Your BMD score will first be compared with healthy adults 25-35 of the same sex and ethnicity. This will give us a standard deviation (SD) score (Figure below) . It’s the difference between your score and an adult in peak fitness and health. This gives us your T-score.

A weak T-score (below average) can indicate a high risk of bone fractures.

  1. A normal bone density will show a T-score within 1 SD (+1 or -1) of the young adult.
  2. A low bone mass (osteopenia) will show a T-score of 1 to 2.5 SD below the young adult range (-1 to -2.5 SD).
  3. Signs of osteoporosis will show a T-score of 2.5 SD or more below the young adult range (more than -2.5 SD)
  4. Severe osteoporosis will show a T-score of 2.5 SD or more below the young adult range and more than one osteoporotic fracture. 

Bone density charts by age

Once you have your scores, to understand your bone health multiply that score by 10%. It will give you an indication of how much bone density you’ve already lost. 


Bone density through the ages:

  • Bone density increases until the age of 25. 
  • Between 25 and 50, it remains stable, with new bone mass forming equally to bone mass breaking down.
  • From 50 years of age, bone resorption (breakdown) occurs more rapidly than new bone formation. 
  • In menopausal women, bone loss accelerates, which is why it’s so important to increase your calcium intake.
  • Men lose bone density slower than women because their bones are bigger and denser. 
  • The average bone mass for adults is between 3 and 5%.

Where to get the test done

If you’re based in Namibia, ERAD Radiology offers bone density testing at two of our clinics. 

How to check bone density at home 

While you can check your bone density at home, it’s not a reliable method for determining your exact density. But it can give you an indication of whether you need to see your doctor about booking a bone density scan. 

Use this formula to check your bone density:

Weight (pounds) divided by height (inches), squared, multiplied by 703.

How often should you have a bone density scan?

We recommend you get scanned every two to three years if you have osteopenia. In the case of osteoporosis or some other medical condition that could affect your bone density, your doctor may recommend more regular scans.

If you’re on a treatment plan, your doctor wants to know whether your bone density is improving or if they need to try alternate medications.

Next Steps

Are you genetically predisposed to osteoporosis? Do you suspect your bones are weakening? Don’t wait to get tested. There are pre-emptive measures which you can take to strengthen your bones and prevent unnecessary breakages now.  

Speak to your doctor about your concerns and whether you need a bone density scan. If you’re based in Namibia, look for your closest ERAD clinic or book your appointment now.


  1. Na Li, Xin-min Li, Li Xu, Wei-jie Sun, Xiao-guang Cheng, Wei Tian, “Comparison of QCT and DXA: Osteoporosis Detection Rates in Postmenopausal Women”, International Journal of Endocrinology, vol. 2013, Article ID 895474, 5 pages, 2013.
  2. Header Image by Vecteezy
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