Natural background radiation
Radiation from the ground, the air and space reaches everyone, every day. Radiology sources often compare an exam's dose with how long it would take to receive the same amount from this natural background.
Different exams, different doses
A standard chest x-ray gives a very small dose — RadiologyInfo compares it with about ten days of natural background radiation. CT scans give more, because they take many images; the dose depends on the body part and the type of scan.
Keeping the dose low
- Imaging teams follow the principle of using the lowest dose that still answers the clinical question.
- Ultrasound and MRI use no x-rays and are chosen when they can answer the question just as well.
- Tell staff if you are or might be pregnant.
The balance
When an exam is needed, the benefit of an accurate diagnosis is usually far larger than the small risk from the dose. If you are worried, ask the referring clinician why the exam is recommended.
Sources
- Radiation Dose from X-Ray and CT Exams — RadiologyInfo.org — ACR/RSNA. Checked 2026-09-26.
- X-Rays — MedlinePlus — U.S. National Library of Medicine. Checked 2026-09-26.
Editorial update: 2026-09-26.
Medical disclaimer: this is a source-linked educational summary, not individual medical advice, diagnosis, prescription or interpretation of personal results. For severe or rapidly worsening symptoms, call 115.
Antopeloni — plain-language health education from public sources, part of the ZIBADIS network founded by Masoud Moghaddam.
