Medical Radiation Dose Calculator — Imaging Study Exposure
Enter the number of each imaging study you have had in the past year and see your estimated cumulative effective radiation dose in millisieverts (mSv), compared to the US average annual background radiation and ICRP reference limits.
scans
scans
scans
scans
scans
scans
scans
scans
scans
scans
scans
Approximate cumulative effective dose from selected imaging studies
How does this calculator work?
Add up each imaging study you've had: chest X-ray ≈ 0.1 mSv, CT abdomen ≈ 10 mSv, PET scan ≈ 25 mSv. US background radiation is ≈ 3.1 mSv/yr. ICRP sets a 20 mSv/yr occupational limit and 1 mSv/yr public limit. Values are 2009–2024 population averages and are editable estimates — individual doses vary by scanner and protocol.
Formula
How this is calculated
Ionising radiation from medical imaging is measured in millisieverts (mSv) of "effective dose" — a quantity that accounts for both the radiation type and the sensitivity of the organs exposed. Each imaging modality delivers a characteristic range of effective doses. This calculator uses US population average estimates from NCRP Report No. 160 (2009) and ICRP guidance documents: for example a chest X-ray ≈ 0.1 mSv, a chest CT ≈ 7 mSv, and a full-body PET scan ≈ 25 mSv. Your total is the sum of all selected studies.
For context, Americans receive on average about 3.1 mSv/year from natural background radiation (radon, cosmic rays, terrestrial, and internal sources). The ICRP recommends that radiation workers stay below 20 mSv/year averaged over five years, and that the general public receive no more than 1 mSv/year of planned exposure above background. A single CT abdomen/pelvis (≈ 10 mSv) is well below the threshold at which any deterministic (certain) harm is observed (typically >100 mSv from acute exposure).
Doses shown are approximate population averages as of 2009–2024 and can vary two-fold or more depending on the scanner model, scan protocol, and patient body habitus. This tool is for educational awareness — clinical decisions about imaging benefit vs. risk should involve your physician.
Frequently asked questions
A single CT scan adds a small incremental lifetime cancer risk, estimated at roughly 1 in 2,000 for a 10 mSv abdomen CT — far below the lifetime baseline cancer risk of about 1 in 3. The benefit of an appropriate scan almost always outweighs this risk. Concern is more relevant for repeated high-dose studies over many years.
mGy (milligray) measures absorbed dose — the raw energy deposited in tissue. mSv (millisievert) is effective dose, which weights the absorbed dose by the radiation type and the radiosensitivity of the organs involved. For X-rays and gamma rays the numeric values are similar, but effective dose is more useful for estimating health risk across the whole body.
The doses shown are typical values from published US surveys. Real doses can vary by a factor of 2–10 depending on scanner, protocol, and patient size. For a personalised estimate, ask your radiology department for the dose-length product (DLP) or dose area product (DAP) from your specific study.
Also known as
TG we-Calculate Editorial Team. (2026). Medical Radiation Dose Calculator — Imaging Study Exposure [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/medical-radiation-calculator
TG we-Calculate Editorial Team. "Medical Radiation Dose Calculator — Imaging Study Exposure." TG we-Calculate. 2026. https://we-calculate.com/calculator/medical-radiation-calculator.
TG we-Calculate Editorial Team, "Medical Radiation Dose Calculator — Imaging Study Exposure," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/medical-radiation-calculator
@misc{wecalculate_medical_radiation_calculator, title = {Medical Radiation Dose Calculator — Imaging Study Exposure}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/medical-radiation-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?