Dose-response calibration curve for micronucleus assay: preliminary study

The biological dosimetry was developed to assess or estimate the absorbed dose by individuals that are involved or suspected of involvement in an ionizing radiation exposure event. The absorbed dose estimate is based on the analysis of sensitive and specific biomarkers to radiation and that better reflect the biological damage caused by it. The micronucleus (MN) assay is the most commonly used technique in radiation exposure events involving many people, because it can be applied as a triage method in the determination of exposed individuals significantly or not to ionizing radiation. The international atomic energy agency recommends that any laboratory intending to carry out biological dosimetry should establish its own dose–response data for MN assay due to differences between laboratories in response to MN dose, including the use of different protocols and scoring criteria. This study aimed to start construction of the dose-response calibration curve for MN in the Brazilian Northeast region. As such, blood samples were irradiated with three different absorbed doses (0.5 Gy, 0.75 Gy and 1.0 Gy) using a cobalt-60 source located at the Department of Nuclear Energy (DEN/UFPE). The lymphocyte culture, fixation procedure, staining and analysis of slides were according to the protocols set out in the manual of the IAEA. We observed that with the increasing of the absorbed dose, there is an increase in the presence of MN, but it is still necessary the study of other doses for the construction of a more statistically robust calibration curve. (authors)