Radiobioassay performance evaluation of urine and faeces samples for radiation emergency preparedness

In the event of a radiation emergency, it is necessary to assess intake and radiation dose for the internally contaminated casualties. This paper provides relatively rapid and simple procedures of bioassay. Faeces samples were ashed to improve sample homogeneity. Gamma spectrometry was used for radioactivity measurement. The measured results, including activity of the biosamples and associated uncertainty, were evaluated for traceability based on ANSI N42.22 and bias and precision based on ANIS/HPS N13.30. For all urine customary exercise samples, measurement results of ⁶⁰Co and ¹³⁷Cs were in good agreement with NIST values within 5% and satisfied ANSI N42.22 and ANIS/HPS N13.30 acceptance criteria. In contrast, the uncertainty of ⁵⁷Co was quite large and the activity differed from the NIST value by 18%. For the urine emergency preparedness exercise, all measured results agreed well with NIST values, with less than 10% difference. Synthetic faeces samples included ⁵⁴Mn, ⁶⁰Co, and ¹³⁴Cs. The activity of ⁶⁰Co was different from the NIST value by 9%, whereas the results for ⁵⁴Mn and ¹³⁴Cs were within 3.2%. The measurement procedures given in this study can be applied to assess intake of radionuclides and resulting radiation dose to casualties. (author)