Units of Radioactivity

	SI Unit	Non-SI Unit
Radioactivity	1 becquerel (Bq)	27 picocurie (27 x 10-12 Ci)
Absorbed Dose	1 gray (Gy)	100 rad
Equivalent/Effective Dose	1 sievert (Sv)	100 rem

Becquerel (Bq) is the SI unit of radioactivity, equivalent to 1 nuclear transformation per second.

Gray (Gy) is the SI unit of absorbed radiation dose corresponding to the absorption of 1 joule of radiation energy per kilogram of material.

Sievert (Sv) is the SI unit of absorbed radiation dose in living organisms modified by radiation type and tissue weighting factors. The unit of dose for the terms "equivalent dose" and "effective dose".