In 1975 the General Conference on Weights and Measures gave the becquerel (Bq), defined as one nuclear decay per second, official status as the SI unit of activity.

[6] Therefore: and While its continued use is discouraged by the National Institute of Standards and Technology (NIST)[7] and other bodies, the curie is still widely used throughout government, industry and medicine in the United States and in other countries.

At the 1910 meeting, which originally defined the curie, it was proposed to make it equivalent to 10 nanograms of radium (a practical amount).

According to Bertram Boltwood, Marie Curie thought that "the use of the name 'curie' for so infinitesimally small [a] quantity of anything was altogether inappropriate".

Here are some examples, ordered by half-life: The following table shows radiation quantities in SI and non-SI units: