Radiation units and definitions.
| Unit* . | Quantity Measured . | Definition . |
|---|---|---|
| *Submultiples : 10−2 = centi (c); 10−3 = milli (m); 10−6 = micro. Multiples: 103 = kilo (k); 106 = mega (M); 109 = giga (G). | ||
| Abbreviations: Rad, radiation absorbed dose; Rem, roentgen equivalent in man; SI, Systeme International. Modified from N. Dainiak.29 | ||
| Roentgen (R) | Exposure | Charge (ionization) produced in air by x-rays or gamma rays |
| Rad | Dose | 100 ergs deposited per gram of tissue |
| Gray (Gy) | Dose | SI unit of dose; equals 100 rad |
| Rem | Dose equivalence | Unit that reflects biologic response. It is used to compare various types of radiation |
| Sievert (Sv) | Dose equivalence | SI unit of dose equivalence; equals 100 rem |
| Becquerel (Bq) | Exposure | Disintegration per second; 1 Bq=2.7×10−11 Curie (Ci); 1 Ci=3.7×1010 Bq or 37 GBq |
| KERMA | Exposure | Kinetic energy released in matter |
| Unit* . | Quantity Measured . | Definition . |
|---|---|---|
| *Submultiples : 10−2 = centi (c); 10−3 = milli (m); 10−6 = micro. Multiples: 103 = kilo (k); 106 = mega (M); 109 = giga (G). | ||
| Abbreviations: Rad, radiation absorbed dose; Rem, roentgen equivalent in man; SI, Systeme International. Modified from N. Dainiak.29 | ||
| Roentgen (R) | Exposure | Charge (ionization) produced in air by x-rays or gamma rays |
| Rad | Dose | 100 ergs deposited per gram of tissue |
| Gray (Gy) | Dose | SI unit of dose; equals 100 rad |
| Rem | Dose equivalence | Unit that reflects biologic response. It is used to compare various types of radiation |
| Sievert (Sv) | Dose equivalence | SI unit of dose equivalence; equals 100 rem |
| Becquerel (Bq) | Exposure | Disintegration per second; 1 Bq=2.7×10−11 Curie (Ci); 1 Ci=3.7×1010 Bq or 37 GBq |
| KERMA | Exposure | Kinetic energy released in matter |