Towards new biological dosimetry approaches

Ionizing radiation (IR) is a ubiquitous environmental hazard and a well-known carcinogen. In general, exposures are low but accidents and incidents have led to significant exposures. The response to any radiation accident or incident involving actual or potential IR exposure requires accurate and rapid assessment of the doses received by individuals. This is required for initial 'triage' of exposed individuals, followed by more accurate assessment of doses in those exposed, to determine the most appropriate approach to treatment. Biological dosimetry, based on the scoring of chromosomal abnormalities - especially dicentric chromosomes - in peripheral blood lymphocytes, plays a key role. The dicentric assay is accurate and sensitive; however, it is a labor-intensive assay (>2 days from sampling to initial results), and it has a limited sample capacity available for mass screening following an accident or incident. Recently, many attempts have been made to improve dosimetry using different end-points. Different cytogenetic techniques have been proposed. Other techniques have shown some potential, and studies were performed on protein biomarkers such as histone phosphorylation (γ-H2AX) and telomere length quantification. In this study, we have established the dose response curve between the total intensity of γ-H2AX foci, and validated these results with conventional techniques. Similarly, we have demonstrated the dose response curve between telomere length and in vitro irradiation. This study has identified potential biomarkers (γ-H2AX and telomere length) of radiation exposure. This study must be validated further in different donors and studied in a wide range of doses, especially in very low doses. These two biomarkers can be useful in the progression of knowledge in the effect of low dose exposure. (author)