Is a DEXA Scan Safe? Radiation Dose Explained

Is a DEXA scan safe?

Yes — a DEXA (also written DXA) scan is considered very safe. It uses a very low dose of ionising radiation, delivered by a special kind of X-ray called dual-energy X-ray absorptiometry, to measure the density of your bones. The NHS describes DEXA as using "a much lower level of radiation than standard X-rays" and rates the procedure as "very safe" NHS, 2025. The Royal Osteoporosis Society likewise calls it "very safe," reassuring patients that you don't go into a tunnel and don't need an injection Royal Osteoporosis Society, 2025.

One of the clearest signals of how low the dose is: on a standard chest or abdominal X-ray, staff step behind a screen — but for a DEXA scan the radiographer can stay in the scanning room with you the whole time NHS, 2025. That would not be allowed if the exposure were anything but tiny.

How much radiation does a DEXA scan give you?

Very little — far less than the everyday X-rays most people picture. The two most useful comparisons come from patient-facing bodies. The Royal Osteoporosis Society frames the dose as "similar to the amount we would get from three days of normal life" — in other words, comparable to just a few days of the natural background radiation everyone is exposed to from the ground, food and the air anyway Royal Osteoporosis Society, 2025.

RadiologyInfo, the patient resource jointly produced by the Radiological Society of North America and the American College of Radiology, puts it even more starkly: the amount of radiation used is "less than one-tenth the dose of a standard chest x-ray" and "less than a day's exposure to natural radiation" RadiologyInfo.org (RSNA and ACR), 2023. The exact framing differs slightly between sources — the practical point they agree on is that a DEXA dose sits in the range of ordinary background living, not the range of a hospital diagnostic X-ray.

Does a DEXA scan hurt, and are there any side effects?

No — a DEXA scan is quick and painless, with no injection and no enclosed tunnel. You simply lie on your back on a padded table while a scanning arm passes slowly over your body; the NHS describes the whole thing as "quick and painless" NHS, 2025. An NHS trust patient factsheet confirms the same experience — "a quick and painless procedure" where you are not enclosed and do not pass through a tunnel University Hospital Southampton NHS Foundation Trust, 2022.

As for after-effects, there are none to speak of. RadiologyInfo notes that X-rays have no side effects in the typical diagnostic range used for this kind of exam, and — a point patients often ask about — "no radiation stays in your body after an x-ray exam" RadiologyInfo.org (RSNA and ACR), 2023. You can walk out and carry on with your day immediately.

Can you have a DEXA scan while pregnant?

A DEXA scan is generally avoided in pregnancy. Even though the dose is very small, the guidance here is cautious for a good reason: the NHS advises that bone density scans and X-rays are "not recommended for pregnant women, as X-rays can damage an unborn child" NHS, 2025. NHS trust guidance echoes this, asking patients to tell the team if they are — or might be — pregnant or breastfeeding, precisely because "X-rays can damage an unborn child" University Hospital Southampton NHS Foundation Trust, 2022.

In practice this doesn't rule the scan out — it just means rearranging. The Royal Osteoporosis Society advises that if you are pregnant you will need to move your appointment to a later date Royal Osteoporosis Society, 2025. If there's any chance you're pregnant, tell the clinic in advance so it can be handled properly.

Is the dose low enough for frequent repeat scans?

The dose is low, but it is not zero — and that distinction matters most when you want to scan repeatedly. A single DEXA carries a trivial exposure. But bone health is something you often want to track over time — before and during a weight-loss medication, through the menopause, or year on year as you age — and repeat X-ray exposures, however small, add up.

For most people having an occasional scan, this is a non-issue. If you're weighing up how DEXA compares with a radiation-free alternative for long-term tracking, our guide to REMS vs DEXA scans walks through the trade-offs in detail.

Is there a bone scan that uses no radiation at all?

Yes — REMS uses non-ionising ultrasound, so it involves no ionising radiation whatsoever. REMS stands for Radiofrequency Echographic Multi-Spectrometry. Rather than X-rays, it assesses bone status by analysing the raw, unfiltered ultrasound signals reflected from the spine and hip. A 2023 review in Diagnostics describes REMS as "a non-ionizing technology that evaluates bone status by analyzing raw, unfiltered native ultrasound signals," and highlights the "absence of ionizing radiation" as a genuine advantage over DEXA — while noting good precision and repeatability that support follow-up monitoring Diagnostics, 2023.

A further 2024 Diagnostics paper describes REMS as "an alternative non-ionizing technique for the BMD assessment," characterised by the "absence of ionizing radiations," directly contrasting it with X-ray-based DEXA Diagnostics, 2024. Because there is no X-ray dose to accumulate, a radiation-free approach is particularly well suited to the repeat, serial scanning that monitoring calls for — and to anyone who would simply prefer to avoid X-ray exposure. You can read more in our guide to the radiation-free alternative to DEXA.

This is why Screen My Bones uses REMS ultrasound rather than DEXA. It lets us offer a bone health assessment with no ionising radiation at all, which you can book at one of our UK assessment days as often as tracking your bone health sensibly requires.

None of this means DEXA is unsafe — it plainly isn't. It means that if avoiding radiation altogether or scanning frequently matters to you, a non-ionising option exists.

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This article is part of our screening technology series. To compare the two approaches head to head, see REMS vs DEXA scans.