Whole-body counting provides a direct measure of the total amount of cesium-137 present in the human body at the time of measurement.
The amount of cesium-137 detected is usually reported in activity units of kilo-Becequerel (kBq), where 1 kBq equals 1000 Bq and 1 Bq = 1
nuclear transformation per second (t s-1). The detection of plutonium-239 (239Pu) and plutonium-240 (240Pu)
in bioassay (urine) samples indicates the presence of internally deposited (systemic) plutonium in the body. At the Lawrence Livermore National
Laboratory, plutonium bioassay measurements are performed using a state-of-the-art technology based on Accelerator Mass Spectrometry (AMS) (Brown
et al., 2004; Hamilton et al., 2004; 2007). Under the Marshall Islands Plutonium Urinalysis Program, the urinary excretion of
plutonium from program volunteers is usually described in activity units, expressed as micro-Becquerel (µBq) of 239+240Pu
(the sum of the 239Pu and 240Pu activity) excreted (lost) per day (d-1); where 1 µBq d-1 = 10
–6 Bq d-1 and 1 Bq = 1 t s-1.
Individual Measurement Database
This website provides electronic access to verified whole body counting and plutonium urinalysis data developed under the
Marshall Islands Individual Radiological Surveillance Program at the Lawrence Livermore National Laboratory (1999-present).
Please note that the data for Rongelap Atoll includes resettlement workers and other visitors to the island that are not
necessarily affiliated with the Rongelap population group.