CYTOGENETIC INDICATORS OF ACUTE RADIATION SICKNESS (THE CHORNOBYL EXPERIENCE).

The objective of the study was to improve the biological dosimetry approach among patients with acute radiationsickness of various degrees based on the analysis of radiation-induced chromosome aberrations in peripheral bloodlymphocytes of the victims.

Materials and methods: The study was based on primary cytogenetic data obtained in May 1986 within examina-tion of the 30 clean-up workers («liquidators») having got stage I-III acute radiation sickness. Dose verificationwas performed using the cytogenetic dosimetry based on a culture of peripheral blood lymphocytes with metaphaseanalysis of chromosome aberrations.

Results: A new method of evaluating the results of patients' cytogenetic examination at the beginning of specifictherapy has been developed. Procedure was performed using a model of multiple linear regression (complex of cyto-genetic parameters) and provided a satisfactory diagnostic level (featuring a compliance with initially definedclinical and laboratory diagnoses). Overall frequency of the aberrant cells and radiation markers increased in high-er disease stages. There was a trend of the frequency growth of chromatid-type aberrations with increasing of radi-ation burden. Adequacy of the proposed method based on the regression analysis of cytogenetic results was con-firmed through the preservation of group differences in estimates of disease stage in subjects with verified diagnosis.

Conclusion: Cytogenetic dosimetry in the scope of examination of persons exposed to ionizing radiation is an oblig-atory component of radiation sickness stage verification. The recommended method of cytogenetic data evaluationbefore and at the beginning of detoxification therapy provides a satisfactory level of diagnostics.