What is a DEXA Scan? | Who Should Get One? |How Much Does it Cost? |How it Works | Radiation Exposure |How to Read Your Results | Measure Your Progress | What To Do If You Have Low Bone Density | DEXA Scan Clinic Directory
What is a DEXA Scan?
DEXA stands for Dual Energy X-Ray Absorptiometry and is the most widely used test to measure bone mineral density. It is a testing machine that measures the density of your bones. The calculation is done knowing that the denser the bone, the less X-rays pass through. Usually the more dense your bone, the stronger it is, and the less likely it is to fracture.
There are two different types of DEXA machines. Central DEXAs are large full body machines that measure bone density in the centre of your skeleton, such as your spine and hips.
Peripheral DEXAs are portable much smaller machines that are used to measure bone density on your peripheries such as wrist, heel or finger.
A DEXA machine uses low-energy X-rays and sends two different sources (thus the ‘dual’ part) through the bone in question. Bone blocks some of the X-rays. The more dense your bone is, the less X-rays pass through to the detector. By Two different X-ray sources rather than one are used to double the accuracy in measuring your bone density.
The amount of X-rays that comes through the bone from each of the two X-rays is sent to a computer which calculates an average score of the density of your bone.
A DEXA scan is more accurate than regular x-rays or CAT scans and requires less radiation exposure. See more about radiation and DEXA scans, below.
Who Should Get a DEXA Scan?
DEXA scans are now the best method of diagnosing and monitoring osteopenia and osteoporosis. The National Osteoporosis Foundation’s guidelines state that women over 65, younger post menopausal women who have any osteoporosis risk factors and aging men with any osteoporosis risk factors should be tested with DEXA scans. (1)
There are numerous risk factors that can increase your risk of osteoporosis. Below are a few for you to watch out for. If you say, “That’s me” to two or more on this list, it might be a good idea to ask your doctor about a DEXA scan.
- Your gender: Women are 2x more likely to develop osteoporosis than men. Due to menopause, estrogen decreases sharply, which accelerates bone loss. For example, in the five to seven years following menopause, a woman can lose up to 20% of her bone density.
- Age: In our lifetime, we increase bone mass from childhood to about our mid-thirties at which time we reach our peak bone mass. From then on, we lose about 1% of our bone every year.
- Lack of Exercise: “If you don’t use them, you lose them.” Weight-bearing exercise is one of the best things you can do to increase your bone strength because of the concentrated pressure it puts on your bones.
- Diet: A diet lacking in calcium plays a major role in the development of osteoporosis. Eating calcium-rich foods and supplementing with a quality calcium supplement will ensure you are getting the adequate amounts needed.
- Family history: Having a family member with osteoporosis puts you at greater risk as osteoporosis is genetic.
- Body size: Women and men who have small body frames tend to have a higher risk for osteoporosis.
How Much Does a DEXA Scan Cost?
Well, the Federal Government has advised that if you’re 65 and never had a DEXA, you should get tested. The good news is, Medicare will cover it. They’ll also let you do follow-up DEXAs if you need them, every 2 years and cover it. In certain situations if you’re being treated a year apart, it will be covered by Medicare.
What if you’re less than 65? If you’re a post-menopausal woman under 65, most people feel that if you have risk factors for osteoporosis or fracture, you should have a DEXA. Most of the commercial carriers will cover paying for that DEXA if you’re post-menopausal and you have risk factors.
If your health insurance does not cover the cost of your DEXA scan and you have to pay out of pocket, BlueHealthBook.com suggests that you will be paying about $132 USD for your DEXA scan.
How A Bone Density Scan Works
A DEXA scan involves lying down, generally fully clothed, on a scanning table, and a scanning arm painlessly and non-invasively scans over your spine, and then over your hips, to help determine the quantity of bone that you have. The results are calculated in a computer, and you’re told your T-score; that’s the result of the bone density test. You’re given what’s T-score.
If your score is between 0 and -1, you are considered normal. If it’s between -1 and -2.49, it’s called low bone mass, sometimes referred to as osteopenia, but we prefer low bone mass. If it’s below -2.5, that’s called osteoporosis. You can only use those terms if you’re woman and you’re post-menopausal. If you’re pre-menopausal, you might get one of those labels given to you, but it doesn’t have the same meaning as it does when you’re post-menopausal.
AlgaeCal encourages all current and future customers to measure their bone density with a DEXA scan, and will guarantee an increase in bone mineral density through the use of AlgaeCal Plus and Strontium Boost in as little as 180 days.
Should I Be Concerned About Radiation Exposure?
Thankfully, as you can see from the chart below, there is very little exposure when compared to numerous other types of medical imaging procedures.
|Procedure||Average Effective Dose (mSv)||Range Reported in the Literature (mSv)|
|Bone density DEXA||0.001||0.00 – 0.035|
|X-ray, arm or leg||0.001||0.0002 – 0.1|
|X-ray, panoramic dental||0.01||0.007 – 0.09|
|X-ray, chest||0.1||0.05 – 0.24|
|X-ray, abdominal||0.7||0.04 – 1.1|
|Mammogram||0.4||0.10 – 0.6|
|X-ray, lumbar spine||1.5||0.5 – 1.8|
|CT, head||2||0.9 – 4|
|CT, cardiac for calcium scoring||3||1.0 – 12|
|Nuclear imaging, bone scan||6.3||?|
|CT, spine||6||1.5 – 10|
|CT, pelvis||6||3.3 – 10|
|CT, chest||7||4.0 – 18|
|CT, abdomen||8||3.5 – 25|
|CT, colonoscopy||10||4.0 – 13.2|
|CT, angiogram||16||5.0 – 32|
|CT, whole body||variable||20 or more|
For perspective, the amount of radiation emitted that’s listed on the chart above for a DEXA (0.001) is less than what you would get from a New York to L.A. flight.
If you go back a few decades, the only place to measure the health of your bones was at a hospital using a Central full body DEXA machine . But to meet the demand for the ever increasing cases of osteoporosis, more affordable, portable machines to test bone density were invented.
Due to the wonders of technology, with DEXA machines we can now safely, quickly and painlessly spot a bone density issue far on the distant horizon – and then do something about it – before a bone fracture alerts you to the problem.
How to Read Your DEXA Scan Results
That’s ok. And totally normal.
Which is why we’re going to discuss your T and Z-scores (the main numbers shown after your DEXA scan) and break them down so they’re easily understandable.
Here’s the basic understanding:
- Above -1 = Your bone density is considered normal
- Between -1 and -2.5 = Your score is a sign of osteopenia, a condition in which bone density is below normal and may lead to osteoporosis
- Below -2.5 = Your bone density indicates you have osteoporosis
But let’s dig in a little more…
What’s My Z-Score and Why Is It Useful?
In technical speak, the Z-score is a measure of the number of standard deviations away that your bone mineral density is from the average person of your age and gender.
An easy way to think about it is that your Z-score helps you see how you’re doing compared to other people in your age range.
As you know, one in two women over age 50 will break a bone because of osteoporosis. So if you’re over 50, the Z-score is a good way to understand how your bone health measures up to people your own age. But when it comes to your overall bone health there is a better indication of how you’re doing. Enter the T-Score.
What is a T-Score and What Does it Tell Me?
The T-score is a measure of the number of standard deviations your bone density is away from a “Young Adult’s” bone density. It gives you an idea of how you compare to someone considered to be at peak bone health.
Once you reach your peak bone mass around age 40, you begin to lose 1% of your bone mineral density each year on average. That is why comparing your bone density to a young adult’s is more practical because they are at a lower risk for fractures.
The pictures below will give you a visual representation of your scores.
For both rows pictured below, the number on the top of each figure is the T-score for the Bone Mineral Density (BMD) that will be reported for any bone density test you’ve taken (Left Femur, Right Femur, Spine, or Total Body).
At the bottom of each figure is a “%” score associated with the T-score value. Using a scale of 1 to 100, the “%” score is how your BMD compares to people of your gender in the standard comparison group of “Young Adults” that is used to diagnose osteopenia and osteoporosis.
For example, if your T-score was 0.6, your “%” score would be “73%” suggesting that your BMD was better than 73 out of 100 people of your gender in the comparison group and worse than only 26 out of 100.
- The green figures above indicate above average BMD, the darker the green, the better your BMD.
- The yellow figures indicate that you are in low bone density territory.
- The orange figures indicate Osteopenia (-1.0 to -2.4) , where bone density is below normal and may lead to osteoporosis.
- The red figures indicate Osteoporosis (-2.5 and below) which is severe bone loss. Making significant changes to your lifestyle is crucial if you are to increase your bone density.
What’s the Best Way to Measure my Progress?
You may have been told by your Doctor that your BMD has increased by X percent. While this is a good indicator of how much you improved, you can also use the “%” score associated with your T-score, which is at the bottom of each figure mentioned above.
For example, let’s say your T-scores increased from 0.6 to 0.8. Instead of saying it improved by 33.3%, just look up the “%” score for 0.6, (“73%”) and 0.8 (“79%”).
As you can see, your BMD went from better than 73% of “Young Adults” to better than 79% of “Young Adults” – a more accurate measure of change.
What You Can Do If Your Results Show Low Bone Density or Worse…
If your bone density test results show you are in the osteopenia or osteoporosis range, it’s time to make some lifestyle changes if you’re to avoid a fracture and the other complications that can come with weak bones.
While low bone density is not your fault (it’s a natural part of aging) there are some things you can do about it.
Incorporating regular weight bearing exercises, eating a diet that is rich in vegetables, fruits, nuts and seeds and lean meats, and supplementing with AlgaeCal Plus are a few of the top things you can do to kick start your bone building progress.
Studies show that when taken together, AlgaeCal Plus and Strontium Boost will increase bone density in 6-12 months. They work together to improve your bone mineral density by replacing ALL the vitamins and minerals you are losing – not just calcium. When taken together with a proper diet and by incorporating the right exercises, your body can’t help but produce strong healthy bone, even in your 80’s and beyond.
DEXA Scan Clinic Directory
Vancouver, British Columbia, Canada
Mobile DEXA scans and body composition imaging in the Vancouver British Columbia area
Vancouver DEXA Scan
More coming soon, if you would like to see your DEXA scan clinic listed here please contact us.
- National Osteoporosis Foundation (NOF) : http://www.nof.org/
- Mettler FA, et al. “Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog“, Radiology (July 2008), Vol. 248, pp. 254–63.