METHODOLOGY OF RECONSTRUCTION OF INDIVIDUALIZED EXPOSURE DOSES FOR PERSONS RESIDING AT RADIOACTIVELY CONTAMINATED TERRITORIES OF UKRAINE.

Objective: Development of methodology for reconstruction of individualized exposure doses for persons residing atradioactively contaminated after Chornobyl accident territories.Materials and methods of research. The methodology is based on the data of radio-ecological (ground, meal) anddosimetric (WBC measurements) monitoring held in Ukraine in 1986-2013, the results of which are saved in databases of Central Ecological and Dosimetric Register of Radiation Protection Laboratory of NRCRM.

Comparative Histopathologic Analysis of "Radiogenic" and "Sporadic" Papillary Thyroid Carcinoma: Patients Born Before and After the Chernobyl Accident.

Background: The issue of whether radiation-induced thyroid cancer is pathologically different from sporadic remains not fully answered. This study compared structural characteristics and invasive features of papillary thyroid carcinoma (PTC) in two age-matched groups: patients who were children (≤4 years old) at the time of the Chernobyl accident and who lived in three regions of Ukraine most contaminated by radioactive iodine I ("radiogenic" cancer), and those who lived in the same regions but who were born after 1987 and were not exposed to I ("sporadic" cancer). Further, the histopathologic features of PTC were analyzed in relation to age and individual I thyroid dose.

Anaplastic lymphoma kinase (ALK) gene rearrangements in radiation-related human papillary thyroid carcinoma after the Chernobyl accident.

Childhood radiation exposure has been associated with increased papillary thyroid carcinoma (PTC) risk. The role of anaplastic lymphoma kinase (ALK) gene rearrangements in radiation-related PTC remains unclear, but STRN-ALK fusions have recently been detected in PTCs from radiation exposed persons after Chernobyl using targeted next-generation sequencing and RNA-seq. We investigated ALK and RET gene rearrangements as well as known driver point mutations in PTC tumours from 77 radiation-exposed patients (mean age at surgery 22.

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.

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.

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.

Interpretation of results of radioiodine measurements in thyroid for residents of Ukraine (1986).

Objective: The purpose of this research is to make analysis, revision and estimation both reliability and accuracy of all measurements of radioiodine in the thyroid for residents of Ukraine, which were performed in 1986, and to justify the calibration factors to be applied for interpretation of measurements performed by non-calibrated devices.

Materials And Methods: The radioiodine activity in the thyroid for residents of the most contaminated oblasts of Ukraine has been calculated on the base of 150 thousands direct measurements of the content of 131I in thyroid obtained in the frames of the thyroid monitoring in 1986. A method for the calculation of measurement errors has been developed and the accuracy of the errors has been determined assuming that the density of errors' distribution for main parameters of the measurements is close to Gaussian.

Generalized results of individualized exposure doses reconstruction for the subjects of Ukrainian State Register of persons, affected due to Chernobyl accident.

Since 2007, the department of dosimetry of NRCRM has been working for to supply the Ukrainian State Register (SRU) of persons affected due to Chernobyl accident by exposure doses estimations. As of now, the individualization of doses has been performed for nine raions located in Kyiv, Zhytomyr, Rivne and Chernihiv oblasts. The structure of raion-specific models used for the reconstruction of individualized doses was described in detail in the previous 19-th issue of this journal (2014).

Basic Principles and Practices of Integrated Dosimetric Passportization of the Settlements in Ukraine.

The purpose of the review is to demonstrate the results of dosimetric passportization (performed in 1991-2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of aftermath of the Chornobyl accident directed on recovery through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring.

Histopathological features of papillary thyroid carcinomas detected during four screening examinations of a Ukrainian-American cohort.

Background: There are limited data on the histopathology of papillary thyroid carcinomas (PTCs) diagnosed in irradiated populations. We evaluated the associations between iodine-131 dose and the histopathological characteristics of post-Chernobyl PTCs, the changes in these characteristics over time, and their associations with selected somatic mutations.

Methods: This study included 115 PTCs diagnosed in a Ukrainian-American cohort (n=13,243) during prescreening and four successive thyroid screenings.

Individualized internal exposure doses reconstruction for the persons of Ukraine State Register: Report 2. Locally-specific models and doses of persons living in Kozelets and Ripky raions of Chernihiv oblast.

Study objective. Development a system of models and procedures for the individualized internal exposure doses reconstruction for the subjects of Ukrainian State Register of persons, affected due to the Chornobyl accident (SRU) and residing in radioactive contaminated territories of Kozelets and Ripky raions of Chernihiv oblast. Materials and methods.

Individualized internal exposure doses reconstruction for the persons of Ukraine State Register: Report 1. Locally-specific models and doses of persons living in Rokytne raion of Rivne oblast, Ovruch raion of Zhytomyr oblast and Ivankiv raion of Kyiv oblast.

Study objective. Dosimetric support of the Ukrainian State Register of persons, affected due to the Chornobyl accident (SRU). Development the system of models and procedures for the individualized internal doses reconstruction for the subjects of SRU residing in radioactive contaminated territories of Rokytne raion of Rivne oblast, Ovruch raion of Zhytomyr oblast and Ivankiv raion of Kyiv oblast.

Thyroid cancer study among Ukrainian children exposed to radiation after the Chornobyl accident: improved estimates of the thyroid doses to the cohort members.

In collaboration with the Ukrainian Research Center for Radiation Medicine, the U.S. National Cancer Institute initiated a cohort study of children and adolescents exposed to Chornobyl fallout in Ukraine to better understand the long-term health effects of exposure to radioactive iodines.

Impact of uncertainties in exposure assessment on estimates of thyroid cancer risk among Ukrainian children and adolescents exposed from the Chernobyl accident.

The 1986 accident at the Chernobyl nuclear power plant remains the most serious nuclear accident in history, and excess thyroid cancers, particularly among those exposed to releases of iodine-131 remain the best-documented sequelae. Failure to take dose-measurement error into account can lead to bias in assessments of dose-response slope. Although risks in the Ukrainian-US thyroid screening study have been previously evaluated, errors in dose assessments have not been addressed hitherto.

Reconstruction of individual thyroid doses to the Ukrainian subjects enrolled in the Chernobyl Tissue Bank.

The Chernobyl Tissue Bank (CTB) is an organisation that collects and stores samples of tumoral thyroid tissue obtained from Ukrainian and Russian subjects who were treated surgically for a thyroid cancer and had been exposed to (131)I from the Chernobyl accident. By 2012, the CTB had collected specimens of thyroid tissue from 2267 residents of Ukraine for the purpose of radiation research. Arithmetic mean thyroid doses and uncertainties have been estimated for all but 24 subjects for whom residence at the time of exposure was not found.

Estimating thyroid masses for children, infants, and fetuses in Ukraine exposed to (131)I from the Chernobyl accident.

For the purpose of improving retrospective internal thyroid dose estimations for children and adolescents following the Chernobyl accident, age- and gender-dependent thyroid masses have been estimated for the children of Kiev and Zhytomyr oblasts, which are two of the most contaminated regions of Northern Ukraine. For children ages 6-16 y, the thyroid masses were based on the measurements by ultrasound of the thyroid volumes of about 60,000 children performed by the Sasakawa Memorial Health Foundation in the 1990s. For children aged 0 to 36 mo, because thyroid mass values for Ukrainian children were not found in the literature, autopsies were performed for the specific purpose of this paper.

Estimation of the thyroid doses for ukrainian children exposed in utero after the chernobyl accident.

This paper describes methods for estimating thyroid doses to Ukrainian children who were subjects of an epidemiological study of prenatal exposure and presents the calculated doses. Participants were 2,582 mother-child pairs in which the mother had been pregnant at the time of the Chernobyl accident on 26 April 1986 or in the 2-3 mo following when (131)I in fallout was still present. Among these, 1,494 were categorized as "exposed;" a comparison group of 1,088 was considered "relatively unexposed.

Methods for estimation of radiation risk in epidemiological studies accounting for classical and Berkson errors in doses.

With a binary response Y, the dose-response model under consideration is logistic in flavor with pr(Y=1 | D) = R (1+R)(-1), R = λ(0) + EAR D, where λ(0) is the baseline incidence rate and EAR is the excess absolute risk per gray. The calculated thyroid dose of a person i is expressed as Dimes=fiQi(mes)/Mi(mes). Here, Qi(mes) is the measured content of radioiodine in the thyroid gland of person i at time t(mes), Mi(mes) is the estimate of the thyroid mass, and f(i) is the normalizing multiplier.

A screening study of thyroid cancer and other thyroid diseases among individuals exposed in utero to iodine-131 from Chernobyl fallout.

Background: Like stable iodine, radioiodines concentrate in the thyroid gland, increasing thyroid cancer risk in exposed children. Data on exposure to the embryonic/fetal thyroid are rare, raising questions about use of iodine 131 (I-131) in pregnant women. We present here estimated risks of thyroid disease from exposure in utero to I-131 fallout from the Chernobyl nuclear accident.

Radiation dosimetry for highly contaminated Belarusian, Russian and Ukrainian populations, and for less contaminated populations in Europe.

The explosions at the Chernobyl Nuclear Power Plant (CNPP) in Ukraine early in the morning of 26 April 1986 led to a considerable release of radioactive materials during 10 d. The cloud from the reactor spread many different radionuclides, particularly those of iodine (131I) and cesium (134Cs and 137Cs), over the majority of European countries, but the greatest contamination occurred over vast areas of Belarus, the Russian Federation and Ukraine. As the major health effect of Chernobyl is an elevated thyroid cancer incidence in children and adolescents, much attention has been paid to the thyroid doses resulting from intakes of 131I, which were delivered within 2 mo following the accident.

Design and operation of the internal dosimetry program for the Chornobyl 'shelter implementation plan'.

The paper discusses the system of individual monitoring for internal exposure, deployed by the Ukrainian Radiation Protection Institute as an integral component of the Shelter Implementation Plan (SIP) at the Chornobyl industrial site. SIP anticipates involving of up to 10,00 workers of numerous SIP contractors. A typical daily shift comprises several hundred workers.

Post-Chernobyl thyroid cancers in Ukraine. Report 2: risk analysis.

On April 26, 1986, the worst nuclear reactor accident to date occurred at the Chornobyl (Chernobyl) power plant in Ukraine. Millions of people in Ukraine, Belarus and Russia were exposed to radioactive nuclides, especially (131)I. Since then, research has been conducted on various subgroups of the exposed population, and it has been demonstrated that the large increase in thyroid cancer is related to the (131)I exposure.

Questionnaire- and measurement-based individual thyroid doses in Ukraine resulting from the Chornobyl nuclear reactor accident.

The U.S. National Cancer Institute (NCI), in cooperation with the Ministries of Health of Belarus and of Ukraine, is involved in epidemiological studies of thyroid diseases presumably related to the Chornobyl accident, which occurred in Ukraine on 26 April 1986.

Breast cancer in Belarus and Ukraine after the Chernobyl accident.

An increase in breast cancer incidence has been reported in areas of Belarus and Ukraine contaminated by the Chernobyl accident and has become an issue of public concern. The authors carried out an ecological epidemiological study to describe the spatial and temporal trends in breast cancer incidence in the most contaminated regions of Belarus and Ukraine, and to evaluate whether increases seen since 1986 correlate to radiation exposure from the Chernobyl accident. The authors investigated the trends through age-cohort-period-region analyses of district-specific incidence rates of breast cancer for Gomel and Mogilev regions of Belarus and Chernigiv, Kyiv and Zhytomir regions of Ukraine.

Post-Chornobyl thyroid cancers in Ukraine. Report 1: estimation of thyroid doses.

About 1.8 EBq of 131I was released into the atmosphere during the Chornobyl accident that occurred in Ukraine on April 26, 1986. More than 10% of this activity was deposited on the territory of Ukraine.

The need for changes in ICRP policy: some examples based on the Chernobyl experience in Ukraine.

Current ICRP policy in radiological protection (ICRP Publication 60) is based on the independent restriction of exposure and sources for practice and intervention. Such subdivision of exposure and sources leads to a number of problems and contradictions in different applications. In a recent memorandum of the ICRP, published in the Journal of Radiological Protection in 2001, and ICRP Publications 81 and 82, the directions for settling some of these problems are indicated.