How do I prepare?
No calcium supplements for 24 hours beforehand, as they can affect the reading.
No barium studies or injected contrast in the week before — they interfere with the scan.
Wear clothing without metal zips, buttons or clasps, which have to be removed or worked around.
Does it involve radiation?
A very small amount — substantially less than a chest X-ray, and considerably less than a day of ordinary background exposure.
It is quick, painless and you stay fully clothed.
I have osteopenia. Do I need treatment?
Usually not — and this is worth being clear about, because the word frightens people.
Osteopenia means bone density lower than a young adult's. It is not a disease, and most people with it never fracture.
What matters is your calculated fracture risk, which combines the score with age, previous fractures, family history and steroid use. For most people with osteopenia the answer is exercise, vitamin D and reassessment — not medication.
What is the difference between T-score and Z-score?
T-score compares you with a healthy young adult, and defines osteoporosis.
Z-score compares you with people your own age, and matters most in younger adults — a low Z-score prompts looking for an underlying cause.
What actually strengthens bone?
Weight-bearing and resistance exercise, which is the most effective thing available and costs nothing.
Adequate vitamin D and dietary calcium, stopping smoking, and keeping alcohol within limits.
HRT also protects bone, which is relevant for women going through menopause — particularly early menopause.
How often should it be repeated?
Not more often than every two years, and often less.
Bone density changes slowly, and an earlier repeat cannot distinguish real change from measurement variation.
I broke my wrist falling over. Does that matter?
Yes, considerably — and it is worth mentioning even if it feels unrelated.
A fracture from a fall from standing height is a fragility fracture, and it is one of the strongest predictors of the next one. It often means treatment regardless of the scan result, and it usually qualifies you for a free NHS DEXA.
Is a heel ultrasound scan the same thing?
No. Peripheral devices offered at pharmacies and health fairs are not diagnostic and cannot be used to decide treatment.
A reassuring heel result should not be relied on if you have risk factors.
What else should be checked?
Vitamin D, calcium, kidney function and thyroid function — and in men, testosterone, since low levels contribute to bone loss and are often overlooked.
Coeliac disease is also worth considering, because it causes bone loss through poor absorption and is regularly diagnosed this way.