RECONSTRUCTION, VERIFICATION AND ANALYSIS OF RESULTS OF WBC MEASUREMENTS DATED 1986 THAT WERE INPUTTED TO ELECTRONIC DATABASE IN 2019-2021. / VIDNOVLENNIa, VERYFIKATsIIa TA ANALIZ REZUL'TATIV LVL/VYMIRIuVAN' 1986 R., ShchO VNESENI DO ELEKTRONNOÏ BAZY U 2019­2021 rr.

Objective of research is to improve the electronic database of WBC measurements dated 1986 by inputting of newinformation from paper carriers, reconstruction of information gaps, verification and analysis of new entered data,revision of internal exposure doses that are based on results of WBC measurements dated 1986. MATERIALS AND METHODS: In 2013-2015 during a revision of databases (DB) of WBC measurements results dated1986-2014, it was discovered a great amount of paper carriers with information about WBC measurements, includ-ing the ones dated 1986, that were not inputted to the electronic DB. The paper carriers were systematized andordered by the following indicators: place of residence of a person and place of WBC measurement, institution andoperator that made the measurement, measurement device and date of measurement. For a comfortable inputtingof the information to the electronic DB, it was additionally created a form which exists as an option in existing program complex Silbody (Version 19.0.9). In the revised DB of WBC measurements dated 1986 internal exposure dosesfrom radio-cesium of Chornobyl origin were computed based on an ecological and dosimetric model for radio-cesiummigration in environment and a model for radio-cesium metabolism in human body. In the work, mathematical andstatistical methods of research were used. RESULTS: In 2019-2021 additionally 35,319 notes were inputted to the electronic DB of WBC measurement dated1986, and as a result its volume increased in 2.2 times. Mostly those are data on results concerning residents of Kyiv,Zhytomyr, Donetsk, Cherkasy, Odessa, Ivano-Frankivsk, and Rivne Oblasts. It was established the information onmeasurement devices and respectively on the minimal detected activity (MDA) for 27,119 notes (76.7 % of all newentered). Information is reconstructed about the body mass of all persons under investigation. Evaluation is madefor values of intake of incorporated radionuclides 137Cs and 134Cs for all new entered to DB. Quality of reconstructedinformation was analyzed. To group 1, «qualitative¼, it was classified 18,598 notes (53 % of all new entered), measurements in 1986 (including new entered). Dose not exceeding 1 mSv was obtained by 80 % of adults (older than20), as well as 73 % of persons younger than 20. CONCLUSION: To DB of WBC measurements, it was additionally inputted 35,319 notes on results of measurementsdated 1986. New entered information is verified and distributed by the quality groups. Individual exposure dosesevaluated based on those data can be used for further scientific research.

RESULTS OF WBC MEASUREMENTS WERE MADE AT RADIOACTIVELY CONTAMINATED TERRITORIES OF UKRAINE IN 1986-2014 (REVISION AND ANALYSIS). / REZUL'TATY LVL6VYMIRIuVAN', PROVEDENYKh NA RADIOAKTYVNO ZABRUDNENYKh TERYTORIIaKh UKRAÏNY U 1986-2014 rr. (REVIZIIa TA ANALIZ).

OBJECTIVE: revision, analysis, and significant improvement of quality of the database of WBC measurements made in1986-2014 at radioactively contaminated territories of Ukraine by the use of renewal of informational gaps andimprovement of the model for assessment of internal exposure doses. MATERIALS AND METHODS: Inthe periodfrom 1986 to 2014 experts of the Whole Body Counters Laboratory of NRCRMaccumulated about 1.5 million results of WBC measurementsof radio-cesium incorporated in the body of personsresiding at the territories which are radioactively contaminated due to Chornobyl accident. Most of measurements(~64 %) were made during the first 15 years after the accident. The most of measurements were made in Kyiv (~23 %),Zhytomyr (~36 %), Rivne (~20 %) and Chernihiv (~5 %) Oblasts. Works on revision of database of WBC measurementsincluded: transformation of data saved in paper format into electronic form, checking for correctness and correspon-dence of information, renewal of lacking information at the fields of database, improvement of the model for eval-uation of internal exposure doses by the data of WBC measurements. In the model for evaluation of revised doses,it is assumed uniform content of radio-cesium during a year. Reference values are used of metabolism parametersand anthropometric human parameters recommended in publications of ICRP. RESULTS: Revised doses have been reconstructed for 1,386,585 records of data base of WBC measurements that fitspecially elaborated criterions for estimation of quality of results. Among them 604,215 records are WBC measure-ments of children and adolescents younger than 18, and 782,370 records correspond to adult inhabitants of Ukraine,most of which reside in Zhytomyr, Kyiv, Rivne and Chenihiv Oblasts. CONCLUSIONS: Obtained results serve as a ground for further works on improvement of models for evaluation of pass-port doses and individualized exposure doses of subjects registered in Ukrainian State Register - of persons thataffected due to Chornobyl accident. Evaluated doses can be used for epidemiological, clinical and other research.

Reconstruction of individualized doses of subjects from the Ukrainian State Register - of Persons that Affected due to Chornobyl accident and reside in Korosten raion of Zhytomyr oblast. / REKONSTRUKTsIIa INDYVIDUALIZOVANYKh DOZ SUB'IeKTIV DERZhAVNOGO REIeSTRU UKRAÏNY OSIB, IaKI POSTRAZhDALY VNASLIDOK ChORNOBYL'S'KOÏ KATASTROFY, ShchO PROZhYVAIuT' V KOROSTENS'KOMU RAY̆ONI ZhYTOMYRS'KOÏ OBLASTI.

STUDY OBJECTIVE: To elaborate an ecological dosimetric model of reconstruction individualized exposure doses of subjects from the State Register of Ukraine (SRU) - of persons, affected due to Chornobyl accident and reside at the radioactive contaminated territory of Korosten raion of Zhytomyr Oblast, and to calculate exposure doses for those persons. MATERIALS AND METHODS: In the paper, an ecological dosimetric model is presented which is elaborated in order to individualize exposure doses of people who reside in Korosten raion of Zhytomyr Oblast and are registered in SRU. The model is based on the results of radio ecological and dosimetric monitoring held in the period of 1986-2013 at the territory of northern oblasts of Ukraine. Annual dose over each post accidental year consists of the two compo nents: (a) annual effective dose of external gamma exposure (due to radioactive fallout on the ground), and (b) internal exposure of the whole body (due to consumption of meal contaminated by radioactive isotopes). For 1986, the dose of internal exposure is evaluated out of all main radionuclides of radioactive accidental fallout, and after 1987 only for radioisotopes of caesium (134Cs and 137Cs). The parameterization of the model is based on the pre vious experience in working out a complex of ecological dosimetric models for estimation of referent exposure doses of Ukrainian population. RESULTS AND CONCLUSIONS: Individualized doses of external and internal exposure (annual and accumulated) are estimated for the population of various age groups that resides in the settlements of Korosten raion (totally about 100 settlements). Separately the doses are presented for rural settlements of the raion and for the city of Korosten for each year of the post accidental period of 1986-2016. Estimates of doses are given that were accumulated: (a) during 15 years just after the accident, (b) for the period of 2000-2016, and (c) for 30 year period after the acci dent. Mean dose accumulated for 30 years after the Chornobyl accident by residents of rural settlements of Korosten raion is estimated as 19.8 mSv, and for inhabitants of the Korosten city as 20.9 mSv. On condition of permanent res idence in the raion, residents of about 66 % settlements of Korosten raion accumulated the doses in the interval 5 20 mSv during 30 years after the accident. For the residents of about 25 % settlements the accumulated dose is in the interval 20-50 mSv, and for 7 % of settlements it exceeds 50 mSv.

Estimation of radiation risk in presence of classical additive and Berkson multiplicative errors in exposure doses.

In this paper, the influence of measurement errors in exposure doses in a regression model with binary response is studied. Recently, it has been recognized that uncertainty in exposure dose is characterized by errors of two types: classical additive errors and Berkson multiplicative errors. The combination of classical additive and Berkson multiplicative errors has not been considered in the literature previously. In a simulation study based on data from radio-epidemiological research of thyroid cancer in Ukraine caused by the Chornobyl accident, it is shown that ignoring measurement errors in doses leads to overestimation of background prevalence and underestimation of excess relative risk. In the work, several methods to reduce these biases are proposed. They are new regression calibration, an additive version of efficient SIMEX, and novel corrected score methods.

Berkson errors in radiation dose assessments and their impact on radiation risk estimates.

OBJECTIVE: To estimate the influence of Berkson errors in exposure doses on the results of risk analysis within example of radiation epidemiological studies of the thyroid cancer prevalence. MATERIALS AND METHODS: The impact of Berkson errors of the thyroid doses in a dose-response analysis is studied by the method of stochastic simulation. RESULTS: Presence of errors in doses results in bias of the naive estimations of baseline morbidity and absolute risk excess in the linear logistic regression model. With the increase of dose errors the bias of the naive estimate increases almost linearly. The use of the full maximum likelihood method developed by authors improves essentially the estimates of parameters in the excess absolute risk model. CONCLUSION: Ignoring of the significant Berkson errors in dose assessment leads to the bias in estimates of background morbidity (overestimated) and of the excess absolute risk (underestimated). At that the bias is essentially less than the one for the case of classical error.