UnitConverter

Radiation Activity Converter — Becquerel (Bq), Curie (Ci)

Convert between 6 units of radioactivity — becquerel (Bq), kilobecquerel (kBq), megabecquerel (MBq), gigabecquerel (GBq), curie (Ci), and millicurie (mCi). The average human body contains ~8,000 Bq from natural K-40 and C-14. A PET scan uses ~400 MBq of radiotracer. 1 Ci = 37 GBq — originally defined as the activity of 1 gram of radium-226.

Radiation activity Converter
9 units
From
Bq
To
Ci
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About the Radiation Activity Converter

Radioactivity (activity) measures how many nuclear disintegrations occur per second in a radioactive sample. The SI unit is the becquerel (Bq) — one disintegration per second. The curie (Ci) is the older unit based on the activity of 1 gram of radium-226 (3.7 × 10¹⁰ Bq). Activity decreases exponentially with time according to each isotope's half-life. Medical imaging uses millicurie quantities; nuclear power reactors contain exabecquerel levels of activity.

Quick facts
  • The average human body contains about 8,000 Bq of radioactivity from potassium-40 and carbon-14
  • One curie (Ci) = 37,000,000,000 Bq — originally the activity of 1 gram of radium
  • A PET scan uses a radiotracer with activity of 200–400 MBq injected into the patient
  • The Chernobyl reactor core contained roughly 10¹⁸–10¹⁹ Bq of activity at the time of explosion
Common uses: Nuclear medicine, radiation safety, reactor engineering, environmental monitoring, geology