Repeat Bone Density Scans in Ajax: How Often and Why

A first bone density scan is a snapshot. It tells you and your doctor where your bones stand on one particular day. A second scan, months or years later, turns that snapshot into something more useful: a direction of travel. Are your bones holding steady, losing ground or responding to a treatment plan?

Many patients who come to our clinic in Ajax for a bone mineral density scan have been here before. Some are curious why their doctor has asked for another one. Others wonder why the timing seems different from a friend’s, or why their results changed only slightly when they had expected a bigger difference. This article answers those questions in plain language. It does not tell you how often you personally should be scanned; that is a decision for the provider who knows your history. It does explain the reasoning behind follow-up scans so the plan makes more sense.

If you have not yet had a first scan and are wondering whether you need one, start with our guide to who should get a bone density test.

What a follow-up scan is really asking

A baseline scan answers the question “How dense are these bones compared with reference groups?” A follow-up scan asks something different: “How have these bones changed compared with last time?”

That shift matters. On a follow-up report, the comparison with your previous scan can be just as important as the scores themselves. A result that looks similar to last time may be reassuring for one person and a sign that treatment is working for another. A small decrease may be expected in one situation and worth discussing in another. The meaning comes from context, which is why your doctor interprets the report alongside your age, medications, fracture history and other health information.

Common reasons a doctor orders another scan

There is no single schedule that suits everyone. Your provider will think about why you were scanned in the first place and what has happened since. Some of the more common reasons for a repeat scan include:

Checking a baseline that was close to a threshold

If your first result was normal and you have few risk factors, your doctor may feel there is no reason to repeat it for a long while, if at all. If your result was near the line between categories, or you have risk factors that may speed bone loss, they may want to look again sooner.

Monitoring the effect of treatment

People who start a medication for osteoporosis are often rescanned after a period of time to see whether bone density has stabilized or improved. A result showing that bone density has held steady can be a good outcome, since the aim of many treatments is to stop ongoing loss.

Watching for change during a higher-risk period

Some situations can speed up bone loss. Examples include long-term steroid use, some hormone treatments used in breast or prostate cancer care, certain conditions that affect absorption of nutrients, and the years around menopause. Your doctor may suggest repeat scans during periods like these.

Reviewing a break from treatment

Some osteoporosis medications are prescribed for a set period, followed by a pause or a change. A scan may be part of how your doctor reviews the plan at that point.

A new fracture or a change in health

A fracture from a minor fall, a new diagnosis or a new medication can all prompt your doctor to look again, even if your next scan was not yet due.

Why the timing is usually measured in years, not months

People are sometimes surprised to learn that a follow-up scan may not be recommended for a few years. The reason is that bone changes slowly. Over a short period, the true change in bone density is often small, sometimes smaller than the natural variation between two measurements.

Every measurement has a small amount of variation built into it. Even if you were scanned twice on the same day, the numbers might differ very slightly because of tiny differences in positioning. For that reason, a change between scans needs to be larger than this normal variation before it can be treated as a real change in your bones. Some reports refer to this idea as the least significant change.

If scans are repeated too close together, the real change may be hidden inside that measurement wobble, and the result can be harder to interpret. Waiting long enough between scans gives any true change a chance to show up clearly. Your doctor balances that against the need to know sooner in higher-risk situations, and current Canadian guidance on osteoporosis care informs how they make that decision.

Consistency is what makes comparison possible

Because follow-up scans are all about comparison, the conditions of each scan need to be as similar as possible. Several things help.

The same type of equipment

Bone density machines from different manufacturers can produce slightly different numbers for the same person. Comparisons are generally most reliable when the follow-up is done on the same equipment, or at least on the same type of machine with the same set-up. If you have had previous scans elsewhere, let our team and your doctor know when you book, so the report can take that into account.

The same areas of the body

Follow-up scans usually measure the same sites as the baseline, most often the lower spine and hip. Positioning you in a consistent way helps make the measurements comparable.

The same preparation

The preparation instructions are part of keeping results consistent too. For a scan at Rossland Diagnostic Clinic:

• Do not take calcium supplements or iron tablets on the day of the exam until after your scan.
• Wear clothing without zippers or metal fasteners if possible.
• Bring your health card and your requisition.
• If you have recently had a test using contrast dye or a barium study, mention it when you book.

Following the same routine each time removes small sources of difference that could otherwise affect the comparison.

Things that can complicate a comparison

Sometimes, factors unrelated to bone strength can affect a reading. Your report may note them, and your doctor will consider them.

• Arthritis in the spine. Wear-and-tear changes in the spine can make spine measurements look higher than the bone’s actual strength. In some people, the hip measurement becomes more useful over time for this reason.
• Previous spinal fractures. A compressed vertebra can affect readings at that level.
• Hip replacement or other surgery. Metal implants cannot be measured, so the other hip, or a different site, may be used.
• Changes in weight. Significant weight gain or loss between scans can have a modest effect on measurements.

None of these is a reason to avoid a follow-up scan. They are simply reasons why a report sometimes includes notes about which areas were used.

Keeping your own bone health record

Many people have scans years apart, sometimes with different doctors or in different cities. Keeping a simple record makes each follow-up easier for everyone, whether your scans were all done in Ajax or spread across several clinics.

1. Note the date and place of each bone density scan you have had.
2. Ask your doctor for a copy of the reports, or note what they told you about the results.
3. List your bone-related medications with the dates you started and stopped them.
4. Record any fractures, including how they happened.
5. Bring the record to appointments with your doctor and mention previous scans when you book.

This record can be particularly helpful for people who moved to Ajax from elsewhere, or who split their time between Durham Region and another community.

Questions to ask about your follow-up plan

If a repeat scan has been suggested, or you are wondering whether you need one, these questions can help:

• What are we hoping to learn from the next scan?
• When should I have it, and what would make you want to scan sooner?
• Should my next scan be done at the same clinic as my last one?
• How will the result change my care plan?
• Apart from the scan, what else should we be watching, such as falls, height loss or new medications?

For more on the other side of fracture prevention, our article on preventing falls and fractures covers strength, balance and what to do after a fall.

Key takeaways

• A follow-up bone density scan is mainly about comparison with your previous result.
• How often you are scanned depends on your results, risk factors and treatment, and is decided by your health-care provider.
• Bone changes slowly, and every measurement has a little natural variation, so scans are usually spaced far enough apart for real change to show.
• Comparisons are most reliable when the same type of equipment, sites and preparation are used each time.
• Keeping a personal record of scans, fractures and medications makes follow-up easier.

Booking your next bone density scan

If your doctor has given you a requisition for a follow-up scan, our team at Unit 102, 300 Rossland Road East in Ajax can help. The bone mineral density scan is quick, painless and uses low-energy X-ray, and our ground-floor clinic has free parking. Call 905-426-3111 or request an appointment, and let us know about any previous scans when you book.