A plain X-ray uses a very low dose of radiation and has no short-term effects — nothing you'll feel, and no radiation left in your body afterwards. The only consideration is a very small, theoretical increase in lifetime cancer risk, which hasn't been clearly demonstrated at these low doses. A chest X-ray is about 0.02 mSv — a few days of natural background radiation — and the benefit of the information almost always outweighs the tiny risk.
Key takeaways
- Plain X-rays use a very low dose and have no short-term effects.
- A chest X-ray ≈ 0.02 mSv — a few days of natural background radiation.
- The only concern is a very small, theoretical long-term risk.
- CT and fluoroscopy use considerably more; plain X-ray is at the low end.
X-rays are one of the safest tests in medicine — but they do use radiation, and it’s fair to want the honest picture rather than vague reassurance. Here it is.
No short-term effects
A plain X-ray uses a very low dose, and there are no short-term effects — nothing you’ll feel, and (as covered in our guide to X-ray images) no radiation remains in your body afterwards.[1]
The dose, in real numbers
The clearest way to judge an X-ray dose is against the natural background radiation we all receive — about 1.5–2 mSv a year in Australia.[2]
- A chest X-ray is around 0.02 mSv — roughly two to three days of background.
- Dental and limb X-rays are lower still.
- Most plain X-rays are a small fraction of a year’s background radiation.
By contrast, CT and fluoroscopy deliver considerably more, which is why plain X-rays sit at the very low end of the scale.[1]
The only real consideration: a tiny theoretical risk
The single long-term consideration is a very small, theoretical increase in lifetime cancer risk from any radiation above background.[1] Two things keep it in perspective:
- At the low doses used in plain X-rays, this increase has not been clearly demonstrated — it’s too small to measure against the cancer risk we all carry anyway.
- The risk is estimated cautiously, by scaling down from situations involving far higher doses — deliberately erring on the side of safety.[1]
For any single, genuinely needed X-ray, the benefit — a correct diagnosis, the right treatment — almost always outweighs this tiny risk.
How the dose is kept low
Radiographers use only enough radiation for a clear image, scan only the area needed, and equipment is regularly checked. Every X-ray should have a definite benefit that justifies it — which is why doctors don’t order them “just in case.”[2]
Pregnancy
If you are, or might be, pregnant, tell the radiographer. A single X-ray — especially away from the abdomen, like a chest or limb — is considered low-risk, but the team will confirm it’s needed and use shielding where appropriate.[1]
Frequently asked questions
How dangerous is an X-ray?
For a plain X-ray, very little: no short-term effects, and only a tiny theoretical long-term risk. The benefit almost always outweighs it.[1]
Does the radiation stay in my body?
No — there’s no radiation left in your body after an X-ray. It’s only present while the machine is on.[1]
Should I worry about having several X-rays?
The small theoretical risk is treated as cumulative, so unnecessary X-rays are avoided — but plain X-rays are such low doses that a few, when needed, are not a concern. Tell your doctor if you’ve had a lot of imaging.[1]
Sources
- RANZCR / InsideRadiology — Radiation risk of medical imaging — www.insideradiology.com.au/radiation-risk/
- ARPANSA — Medical imaging radiation doses — www.arpansa.gov.au/understanding-radiation/radiation-sources/more-radiation-sources/medical-imaging
- RadiologyInfo.org (RSNA & ACR) — Radiation dose — www.radiologyinfo.org/en/info/safety-xray
