Typical radiation doses
From a dental X-ray to acute radiation sickness: typical doses from natural background, medical imaging, dose limits and acute exposure — to put mSv and Gy on a real-world scale.
| A dental X-ray (intraoral) | 0.005 | mSv | once | Mettler et al. 2008 |
|---|---|---|---|---|
| A chest X-ray (PA) | 0.02 | mSv | once | Mettler et al. 2008 |
| A year of potassium-40 inside your body | 0.17 | mSv | per year | UNSCEAR 2008 |
| A year of cosmic rays (world average) | 0.39 | mSv | per year | UNSCEAR 2008 |
| A mammogram | 0.4 | mSv | once | Mettler et al. 2008 |
| Annual limit for the public (artificial sources) | 1 | mSv | per year | ICRP 103 |
| A year of inhaled radon (world average) | 1.3 | mSv | per year | UNSCEAR 2008 |
| A head CT scan | 2 | mSv | once | Mettler et al. 2008 |
| A year of natural background (world average) | 2.4 | mSv | per year | UNSCEAR 2008 |
| Average annual dose in the US (with medicine) | 6.2 | mSv | per year | NCRP 160 |
| An ¹⁸F-FDG PET scan (370 MBq) | 7 | mSv | once | ICRP 128 |
| An abdominal CT scan | 8 | mSv | once | Mettler et al. 2008 |
| Annual limit for radiation workers (5-year average) | 20 | mSv | per year | ICRP 103 |
| Acute whole-body dose: radiation sickness begins | 1000 | mGy (acute, whole body) | once | ICRP 103 |
| Acute whole-body dose: about half die without treatment | 4000 | mGy (acute, whole body) | once | ICRP 103 |
Effective dose (mSv) is a protection quantity for comparing exposures, not an individual’s risk; actual personal doses can differ several-fold. The acute rows are whole-body absorbed doses (mGy) causing deterministic effects; they cannot be added to or compared directly with small effective doses.