Radiation dose comparison
| Procedure | Effective dose, mSv* | Chest radiograph equivalents, no. | Equivalent background radiation time | Increased risk of fatal cancer† |
|---|---|---|---|---|
| Chest radiograph (posteroanterior) | 0.02 | 1 | 2.4 d | — |
| Chest/abdomen CT scan | 10.00 | 500 | 3.3 yr | — |
| 4-slice‡ | 4.55 | 228 | 1.5 yr | 1/2197 |
| 40-slice‡ | 1.60 | 80 | 6 mo | 1/6250 |
| 64-slice‡ | 1.52 | 76 | 6 mo | 1/6579 |
CT = computed tomography.
↵* Based on the assumption of an average effective dose from natural background radiation of 3 mSv/yr (US).
↵† Increased risk of fatal cancer = effective dose (Sv) × risk coefficient of fatal cancer in adults.
↵‡ Newer CT technologies with automatic exposure control and multislice scanning.
Adapted from European Commission. Radiation Protection Report 118. Referral guidelines for imaging. Brussels (Belgium): Directorate-General for the Environment of the European Commission; 2001 (20) and Powers J. Assessment of patient doses from CT scanners used by the Calgary Health Region [thesis]. Calgary (AB): University of Calgary; 2006. (4)