megabecquerel

Megabecquerel (MBq) is an SI unit of radioactivity equal to one million becquerels. A becquerel is defined as one disintegration per second, so one MBq corresponds to 1,000,000 disintegrations each second. The symbol is MBq. The prefix mega denotes 10^6, while the base unit is the becquerel (Bq).

Conversions and relationships: 1 MBq equals 10^6 Bq, and 1 MBq equals 0.001 GBq. In older units, 1 Curie (Ci) equals 37 × 10^9 Bq (37 GBq), so 1 MBq is about 2.7×10^-5 Ci or roughly 27 microcuries (µCi).

Context and use: MBq is used to quantify the activity of radioactive sources and radiopharmaceuticals. It is commonly employed in medical imaging and therapy, environmental monitoring, and industrial radiography. For example, radiotracer doses for single-photon emission computed tomography (SPECT) or positron emission tomography (PET) are typically in the hundreds of MBq for a patient dose, though exact values depend on the isotope and clinical protocol.

Etymology and standard: The unit is named after Henri Becquerel, recognizing his discovery of natural radioactivity. The megabecquerel reflects the SI convention of using prefixes with the becquerel to express larger or smaller activities.