Radioactivity Units

Radioactivity is the spontaneous decay of unstable nuclei of atoms, accompanied by the emission of ionizing radiation.

International System of Units (SI)

Unit of measurement of radioactivity in the international system of units (SI) is becquerel [Bq].
  One Becquerel is equal to one decay per second.
  Becquerel can be used in conjunction with multiplying prefixes, listed below:

• 1 Becquerel [Bq] = 1 decay per second [dps].
• 1 Becquerel [Bq] = 60 decays per minute [dpm].
• 1 Kilobecquerel [kBq] = 1000 Bq.
• 1 Megabecquerel [MBq] = 1000 kBq.
• 1 Gigabecquerel [GBq] = 1000 MBq.

Non-SI units

The most commonly used non-system unit for measuring radioactivity is Curie [Ci].
  1 Ci is equal to the number of decays in 1 gram of radium.

• 1 microcurie [μCi] = 3700 Bq.
• 1 millicurie [mCi] = 1000 μCi.
• 1 Curie [Ci] = 1000 mCi