| Exam | Approximate effective dose | Background radiation equivalent |
| Abdomen Pelvis CT | 10 mSv | 3 years |
| Spine Radiograph | 1.5 mSv | 6 months |
| Extremity Radiograph | 0.001 mSv | 3 hours |
| Head CT | 2 mSv | 8 months |
| Spine CT | 6 mSv | 2 years |
| Chest CT | 7 mSv | 2 years |
| Screening Low-Dose Chest CT | 1.5 mSv | 6 months |
| Chest X-ray | 0.1 mSv | 10 days |
| Coronary CTA | 12 mSv | 4 years |
| Cardiac Calcium Scoring | 3 mSv | 1 year |
| Mammography | 0.4 mSv | 7 weeks |
| DEXA | 0.001 mSv | 3 hours |
| Dental X-ray | 0.005 mSv | 1 day |
| PET/CT | 25 mSv | 8 years |
Note: 1 mSv is the dose produced by exposure to 1 milligray (mGy) of radiation
CTDIvol: measure of the dose per slice of a CT scan. Useful to compare protocol to protocol or scanner to scanner. Less useful for determination of actual patient dose received. Measured in mGy
DLP: The dose actually delivered to the patient for a particular scan. Calculated as the CTDIvol x the length of the scanned volume (called the Z-axis length). Measured in mGy*cm.
Reference:
http://www.radiologyinfo.org/en/info.cfm?pg=safety-xray