Assessment of Cytogenetic Abnormalities by FISH in Lymphocytes from a Victim Accidentally Exposed to Cobalt-60

Abstract

Background: A radiation accident occurred on 14 June 2011 in an industrial facility in Bulgaria with a cobalt source (137 TBq) that was used to sterilize equipment. Five people received doses exceeding 1Gy, which led to the development of acute radiation syndrome. Biological dosimetry based on dicentric analysis was performed and the average acute whole-body doses estimated for the five patients ranged from 1.2 to 5.6 Gy. The purpose of this study was to evaluate induced chromosome aberrations in vivo four months after the accident in the most severely exposed subject. Methods: Fluorescence plus Giemsa (FPG) staining and Fluorescent in situ hybridization (FISH) were used to detect chromosomal aberrations in peripheral blood lymphocytes from the study subject four months after accidental exposure. FISH was performed using DNA probes specific for whole chromosomes 1, 4, and 11. Results: The mean frequency of dicentrics per cell ± SE was 0.425 ± 0.042, determined by FPG. According to FISH analysis, the genomic frequency of apparently simple translocations (ASTs) per cell was 0.678 ± 0.032. Incomplete translocations accounted for approximately 35% of all translocations. For apparently simple dicentrics (ASDs), the genomic frequency was