Cytogenetic and hematological studies in the workers occupationally exposed to low levels of ionizing radiation

Complete text of publication follows. Objective: This study was aimed at detecting both the incidence of chromosomal aberrations and changes in the hematological parameters as biomarkers of possible radiation injury among workers occupationally exposed to low levels of ionizing radiation and detecting the dose-effect relationship. Methods: Samples of peripheral blood were collected from 38 male industrial radiographers exposed to ionizing radiation for 1-16 years and from 24 age- and sex-matched healthy blood donors without radiation history served as control group. All radiation workers were routinely monitored with film badge. Cytogenetic analysis in peripheral blood lymphocytes assessed by the conventional chromosome aberration assay and at least 200 metaphases for each person were scored. The collected blood samples were analyzed for hematological assay using an automatic analyzer Sysmex KX-21, where 14 different parameters were computerized. Mann-Whitney U test was used to compare the frequencies of the unstable aberrations and hematological parameters between test and control groups. Dose-effect relationship and the influence of age and duration of employment was tested by regression analysis. Results and conclusion: The mean frequencies of dicentric and acentric chromosome aberrations were significantly higher in the exposed group than in the control group (P< 0.0005). No correlation between chromosomal aberrations and physical dose and age was observed in the exposed group. Also there is no clear relation between chromosome damage and duration of exposure. However, the increase in chromosome aberrations in the exposed group was not followed by a corresponding hematological depression. The average values of hematological indices were within the reference levels and did not show any significant differences with control group. A tendency of decreasing the absolute lymphocyte count within the referential levels was the only hematological effect in radiation workers. The present results point out the value of chromosome aberration analysis as an important biological indicator and sensitive predictor of the actual risk run by radiation-exposed individuals, in absence of any significant hematological changes. The general underlying principles of the damaging influence of low level radiation in respect to the hemopoiesis are rarely on the mature cells of peripheral blood. The issues of the present biomonitoring study corroborate, in addition to physical dosimetry, the importance of radiation safety programs and the use of up-to-date equipment in reducing the workers' radiation exposure.