Units of Radiation Measure

To comply with DOE orders, this report will present results using the current system followed by Systegrave;me International (SI) units in parentheses. For example, the dose from a typical chest X ray is 10 mrem (0.10 mSv).

Current SystemSI SystemConversion
curie (Ci)becquerel (Bq) 1 CI = 3.7 x 1010Bq
Absorbed dose
rad (radiation absorbed dose)gray (Gy)1 rad = 0.01 Gy
Dose equivalent
rem (roentgen equivalent man)sievert (Sv)1 rem = 0.01 Sv

Converting Dose Equivalent

Because a rem represents a fairly large dose of radiation, dose is best expressed as a millirem, or 1/1000 of a rem. The same is true of sieverts. Dose is expressed in millisieverts (mSv). Because 1 mrem equals 0.01 mSv, converting from millirem to millisieverts is simply a matter of moving the decimal point two places to the left. For example, 267 mrem equals 2.67 mSv.