Thyroid doses in Ukraine due to 131I intake after the Chornobyl accident. Report II: dose estimates for the Ukrainian population

Masiuk, Sergii; Chepurny, Mykola; Buderatska, Valentyna; Иванова, Ольга Михайловна; Boiko, Zulfira; Zhadan, Natalia; Fedosenko, Galyna; Bilonyk, Andriy; Kukush, Alexander; Lev, Tatiana; Таlerko, Mykola; Drozdovitch, Vladimir

doi:10.1007/s00411-021-00930-w

Cited by 6 publications

(2 citation statements)

References 17 publications

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“…For the doses received by the cleanup workers during the residence, the approaches applied to the general population ( 13, 14, 47 ) were used, and 1,000 realizations of cohort doses, considering classification of errors as shared or unshared, were calculated.…”

Section: Categories Of Errors and Uncertaintiesmentioning

confidence: 99%

Assessment of Uncertainties and Errors in Post-Chernobyl Dosimetry

et al. 2023

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The present paper reviews the uncertainties and errors in complex dosimetry systems that were developed to estimate individual doses in different post-Chernobyl (Chornobyl) radiation epidemiology studies among the general population and the cleanup workers. These uncertainties and errors are associated with (i) instrumental radiation measurements of humans and environmental samples, (ii) inherent uncertainties arising from the stochastic random variability of the parameters used in exposure assessment and from a lack of knowledge about the true values of the parameters, and (iii) human factor uncertainties due to poor memory recall resulting in incomplete, inaccurate, or missing responses during personal interview with study subjects conducted long after exposure. Relative measurement errors of 131I thyroid activity associated with devices for measuring radioactivity in the thyroid reached up to 0.86 (coefficient of variation). The inherent uncertainty in estimates of individual doses varied between different studies and exposure pathways (GSD from 1.2 to 15 for model-based doses and from 1.3 to 5.1 for measurement-based doses). The human factor uncertainties can cause individual doses to be underestimated or overestimated by an average of 10 times for model-based doses and 2 times for measurement-based doses calculated for the general population and up to 3 times for doses calculated for cleanup workers. The sources of errors and uncertainties, especially the human factor uncertainties, should be carefully considered in dose assessment for radiation epidemiological studies, with particular attention to studies involving persons without instrumental radiation measurements.

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Section: Categories Of Errors and Uncertaintiesmentioning

confidence: 99%

Assessment of Uncertainties and Errors in Post-Chernobyl Dosimetry

et al. 2023

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“…В Україні поширеною тактикою подальшого ведення хворих з виконаною органозберігаючою операцією на ЩЗ було рутинне призначення замісної терапії левотироксином одразу після виконання операції [8]. У подальшому під контролем рівня тиреотропного гормону (ТТГ) проводили корекції дози препарату.…”

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Analysis of options for prescribing hormone replacement therapy after thyroid organ-sparing surgery

Tovkai

Palamarchuk

Kvitka

et al. 2023

Mìžnarodnij endokrinologìčnij žurnal

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Background. Performing thyroid organ-sparing surgery primarily aims to preserve the quality of life. Organ-sparing surgery should be understood as hemithyroidectomy with mandatory removal of the isthmus and pyramidal lobe of the thyroid (if present). The choice of one or another concept of prescribing hormone replacement therapy remains debatable. The purpose of the study is to determine the proportion of patients who do not need replacement therapy with levothyroxine after organ-sparing surgery on the thyroid gland, among those who were prescribed replacement therapy immediately and one month after discharge from the hospital, as well as to analyze the factors causing hypothyroidism in people with hemithyroidectomy. Materials and methods. The first group included 82 patients with hemithyroidectomy who were prescribed replacement therapy immediately after discharge from the hospital. The second group included 61 patients with hemithyroidectomy. The administration of replacement therapy was postponed for one month. A month after the operation, clinical examinations and monitoring of thyroid-stimulating hormone and free thyroxine indicators were performed. Results. After one month of observation, 72 (87.8 %) of 82 patients in the first group continued to take levothyroxine, and 8 (13.1 %) of 61 persons in the second group began to take it. In the first group, there was a moderate direct correlation between thyroid-stimulating hormone level before surgery and levothyroxine dose one month after (Spearman’s correlation coefficient 0.304, p = 0.009). It was found that the chances of continuing taking levothyroxine after one month in the first group were 47 times higher than the chances of prescribing levothyroxine after one month in the second group. The proportion of patients in the first group who continued to take levothyroxine after one month was significantly higher than the proportion of patients in the second group who started taking levothyroxine after one month (87.8 ± 3.6 % vs. 13.1 ± 3.5 %, p < 0.0001, Fisher’s exact test). Conclusions. Among patients who were prescribed hormone replacement therapy immediately after hemithyroidectomy, 12.2 % did not need to continue taking levothyroxine after one month. Among persons in whom the administration of hormone replacement therapy was postponed for one month after hemithyroidectomy, 86.9 % of patients did not require the use of levothyroxine in the future. The volume of the thyroid remnant ≤ 3.67 cm3 can be considered a predictor for hypothyroidism occurrence in the future, with a high risk of prescribing hormone replacement therapy. The study of such a factor as the ratio of the remnant thyroid volume to the body weight did not provide statistically reliable data for its use as a predictor of hypothyroidism occurrence in the postoperative period.

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Thyroid doses in Ukraine due to 131I intake after the Chornobyl accident. Report I: revision of direct thyroid measurements

Masiuk

Chepurny

Buderatska

et al. 2021

Radiat Environ Biophys

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The increased risk of thyroid cancer among individuals exposed during childhood and adolescence to Iodine-131 ( 131 I) is the main statistically significant long-term effect of the Chornobyl accident. Several radiation epidemiological studies have been carried out or are currently in progress in Ukraine, to assess the risk of radiation-related health effects in exposed populations. About 150,000 measurements of 131 I thyroid activity, so-called 'direct thyroid measurements', performed in May-June 1986 in the Ukrainian population served as the main sources of data used to estimate thyroid doses to the individuals of these studies. However, limitations in the direct thyroid measurements have been recently recognized including improper measurement geometry and unknown true values of calibration coefficients for unchecked thyroid detectors. In the present study, a comparative analysis of 131 I thyroid activity measured by calibrated and unchecked devices in residents of the same neighboring settlements was conducted to evaluate the correct measurement geometry and calibration coefficients for measuring devices. As a result, revised values of 131 I thyroid activity were obtained. On average, in Vinnytsia, Kyiv, Lviv and Chernihiv Oblasts and in the city of Kyiv, the revised values of the 131 I thyroid activities were found to be 10-25% higher than previously reported, while in Zhytomyr Oblast, the values of the revised activities were found to be lower by about 50%. New sources of shared and unshared errors associated with estimates of 131 I thyroid activity were identified. The revised estimates of thyroid activity are recommended to be used to develop an updated Thyroid Dosimetry system (TD20) for the entire population of Ukraine as well as to revise the thyroid doses for the individuals included in post-Chornobyl radiation epidemiological studies: the Ukrainian-American cohort of individuals exposed during childhood and adolescence, the Ukrainian in utero cohort and the Chornobyl Tissue Bank.

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Thyroid doses in Ukraine due to 131I intake after the Chornobyl accident. Report II: dose estimates for the Ukrainian population

Cited by 6 publications

References 17 publications

Assessment of Uncertainties and Errors in Post-Chernobyl Dosimetry

Assessment of Uncertainties and Errors in Post-Chernobyl Dosimetry

Analysis of options for prescribing hormone replacement therapy after thyroid organ-sparing surgery

Thyroid doses in Ukraine due to 131I intake after the Chornobyl accident. Report I: revision of direct thyroid measurements

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