Radiation Measurement Units
| Measurement | U.S. unit | SI unit | Conversion |
| Activity | Curie | Becquerel | 1 mCi = 37 MBq |
| Ionizations in air | Roentgen | C/kg | 1 R = 2.59 × 10−4 C/kg |
| Absorbed dose | Rad | Gray | 100 rad = 1 Gy |
| Equivalent dose (absorbed dose times radiation quality factor) | Rem | Sievert | 100 rem = 1 Sv |
| Effective dose (equivalent dose times tissue weighting factor) | Rem | Sievert | 100 rem = 1 Sv |