Biological Dosimetry by Automated Dicentric Scoring in a Simulated Emergency

Abstract

Dicentric chromosome analysis remains the most widely used method in biodosimetry. It has a lower detection limit of about 0.1 Gy, and allows one to distinguish between whole- and partial-body exposures. A drawback of the dicentric analysis is that it is a time consuming method and maybe difficult to implement in a mass casualty event. To try to increase the analysis capacity, automatic dicentric scoring (ADS) using image analysis software is being incorporated in several laboratories. Here we present the results obtained in an emergency exercise simulating 50 victims. The ability to distinguish different radiations scenarios is evaluated. To simulate whole-body exposures peripheral blood samples were irradiated at doses between 0-4.7 Gy, and to simulate partial-body exposures irradiated and nonirradiated blood were mixed in different proportions. With the data obtained from the first slide analyzed (with about 300-400 cells), 32 of 34 simulated whole-body exposures were correctly classified according to radiation exposure levels. For simulated partial-body irradiations, it was possible to detect them as partial exposures at the end of the first slide analyzed but only at the highest doses. In all cases the classification was updated every time the analysis of one additional slide was finished. The comparison between our present results and those reported in the literature for manual scoring shows that for triage purposes the ADS based on 300-400 cells is similar in efficiency to classifying the cases based on manual scoring of 50 cells. However, if one accounts for the associated uncertainties and the time needed for ADS, we suggest that ADS triage scoring should be based on about 1,000 cells. For final dose estimations the number of cells to score will depend on the initial estimated dose, and on the information contributed from physical dose-reconstruction or clinical symptoms. At doses higher than 1 Gy, we propose analysis of 1,500 and for lower doses or suspected partial-body exposures, the number of cells to score should be 3,000.

Standards in biological dosimetry: A requirement to perform an appropriate dose assessment

“…The validation of the automated image analysis systems, particularly chromosomeaberration image analysis systems, must address the number of false-positives and false negatives per comparison to the expert manual scoring of the same spreads. The outcomes of the studies of Vaurijoux et al [15] and of Gruel et al [16] show that this technique is reproducible when workflow employs QA&QC process. Further, examination of all the methodological parameters is necessary, if any changes are desired to an already established method during a technical validation.…”

Metabolomic applications in radiation biodosimetry: exploring radiation effects through small molecules

“…In the case of radiation biodosimetry, an estimated 50,000 individuals will need to be evaluated within 2 to 6 days after a 10 kt bomb, according to military scenarios for planning (Flood et al, 2016a), although in a city such as New York, NY or Washington, DC the number may well be much higher. Complete blood count (CBC) differential for lymphocyte depletion kinetics, premature chromosome condensation (PCC), dicentric measurement, gene expression, γ-H2AX, cytokinesis block micronucleus assay (CBMN), protein biomarkers, metabolic biomarkers, and electron paramagnetic resonance (EPR) or optically stimulated luminescence (OSL) of teeth have been proposed as some of the methods for radiation biodosimetry (Amundson and Fornace, 2003, Brengues et al, 2010, Coy et al, 2011, Gruel et al, 2013, Lamadrid Boada et al, 2013, Sharma and Moulder, 2013, Sullivan et al, 2013, Xu et al, 2013, Hu et al, 2015, Flood et al, 2016b, Garty et al, 2016, Sproull and Camphausen, 2016). However, some of these assays require a significant length of time for processing and highly trained personnel to perform the assays and interpret the results.…”

Integration of new biological and physical retrospective dosimetry methods into EU emergency response plans – joint RENEB and EURADOS inter-laboratory comparisons

“…Romm et al 2013;Vaurijoux et al 2015). Indeed, Gruel and colleagues demonstrated that semi-automated analysis can also be used in emergency response, with dose estimates based on as few as 50 cells (Gruel et al 2013). The dicentric assay is still recognised as the international gold-standard method for biological dosimetry and classification of genotoxic agents.…”