Bakhanova O. Dosimetric support of analytical epidemiological studies of long-term effects of radiation for Chornobyl cleanup workers

The thesis is devoted to complex dosimetric support of analytical epidemiological studies of long-term biological effects among cleanup workers exposed due to the Chornobyl accident. The thesis presents a series of the research papers published in scientific journals of the first and second quartiles (Q1 and Q2) according to the bibliometric indicators database of the SCImago Journal & Country Rank or Journal Citation Reports. The series of papers submitted for the defense contains a detailed description of the development and implementation of the new methods of retrospective dose assessment for subjects of analytical epidemiological studies of risk factors for long-term stochastic effects of ionizing radiation. The results of the Ukrainian-American ocular study in the cohort of Chornobyl cleanup workers in 1986–1987 for the first time showed a much higher radiosensitivity of the lens and a probable absence of a cataract threshold. This achievement affected the global radiation protection system, in particular, it resulted in the ICRP decision on a revision (7.5 times reduction) of the equivalent dose limit of external irradiation of the lens for Category A personnel - from 150 mSv per year to 20 mSv per year. The new lens dose limit was included in 2011 in the new International Basic Safety Standards for Ionizing Radiation Protection and the Safety of IAEA Radiation Sources and was introduced for EU Member States by Euratom Directive № 2013/59 / EURATOM of 05.12.2013. The results of reconstruction of breast exposure were used in the study of breast carcinogenesis in women participating in Chornobyl cleanup and revealed the functional role of biological markers in response to DNA damage and tumor progression. The results of reconstruction of gonadal doses for parents-subjects of the Ukrainian-American study of transgenerational effects of exposure to ionizing radiation due to the Chornobyl accident in Ukraine allowed to investigate whether children born to parents exposed to radiation have more de novo embryonic mutations. lines (DNM). Sequencing of the entire genome for 130 children (born 1987–2002) and their parents did not reveal an increase in the frequency, distribution, or types of DNM in the offspring of irradiated parents compared to previous studies in the general population. No increase in total DNM was detected either depending on the cumulative radiation dose to the father's gonads or depending on the dose to the mother's gonads.