Assessment of Radiological Hazard of Radioactive Waste Using Effective or Organ Doses: How This May Affect Final Waste Disposal.

The radiological hazard of spent nuclear fuel and radioactive waste slows down further development of nuclear energy systems. The authors evaluate timescales required to reduce the radiological hazard of accumulated waste to the reference level of natural uranium that had been consumed by the nuclear energy system. The estimate of this time scale depends on the radiological hazard metric used in the calculations.

Evaluation of Migration Radiological Equivalence for Dual Component Nuclear Waste in a Deep Geological Repository.

The paper is concerned with the issue of achieving the radiological equivalence (the equivalence of radiation risks) of radioactive waste of nuclear reactors and corresponding mass of natural uranium, taking into account the different migration ability of radionuclides in geological formations and soil. This migration radiological equivalence is being investigated for the deep burial of radioactive waste in the case of the development of a two-component nuclear power system with the concurrent use of thermal neutron reactors and fast neutron reactors. Calculations were performed of radiation doses and radiation risks of cancer death arising from consumption of drinking water from a well above a disposal site.

CLINICAL AND DOSIMETRIC INFORMATION TO SUPPORT LONG-TERM COHORT STUDY OF CHERNOBYL CLEAN-UP WORKERS IN RUSSIA.

The article describes the activities of the Russian National Radiation-Epidemiological Registry (NRER) as the unified federal information system for research and management of individual medical and dosimetry data of people exposed to radiation as a result of the Chernobyl accident and other radiological events. The NRER was created for long-term registration of lifetime changes in the health status of the registered people. We present medical and dosimetry data management process, which is carried out in compliance with approved protocols.

Radiation Risk of Cardiovascular Diseases in the Cohort of Russian Emergency Workers of the Chernobyl Accident.

This paper continues a series of publications that analyze the impact of radiation on incidence of circulatory system diseases in the cohort of Russian recovery operation workers (liquidators) and presents the results of the analysis of cardiovascular disease (CVD) incidence. The studied cohort consists of 53,772 liquidators who arrived in the Chernobyl accident zone within the first year after the accident (26 April 1986 to 26 April 1987). The individual doses varied from 0.

[Non-Parametric Analysis of Radiation Risks of Mortality among Chernobyl Clean-Up Workers].

Analysis of the relationship between dose and mortality from cancer and circulation diseases in the cohort of Chernobyl clean-up workers based on the data from the National Radiation and Epidemiological Registry was performed. Medical and dosimetry information on the clean-up workers, males, who got radiation doses from April 26, 1986 to April 26, 1987, which was accumulated from 1992 to 2012, was used for the analysis. The total size of the cohort was 42929 people, 12731 deaths were registered in the cohort, among them 1893 deaths from solid cancers and 5230 deaths were from circulation diseases.

Radiation-epidemiological Study of Cerebrovascular Diseases in the Cohort of Russian Recovery Operation Workers of the Chernobyl Accident.

The paper presents an analysis of the incidence of cerebrovascular diseases (CeVD) in the cohort of Russian workers involved in recovery tasks after the Chernobyl accident. The studied cohort consists of 53,772 recovery operation workers (liquidators) who arrived in the zone of the Chernobyl accident within the first year after this accident (26 April 1986-26 April 1987). The mean external whole body dose in the cohort was 0.

Estimating the lifetime risk of cancer associated with multiple CT scans.

Multiple CT scans are often done on the same patient resulting in an increased risk of cancer. Prior publications have estimated risks on a population basis and often using an effective dose. Simply adding up the risks from single scans does not correctly account for the survival function.

Incidence and mortality of solid cancer among emergency workers of the Chernobyl accident: assessment of radiation risks for the follow-up period of 1992-2009.

This paper presents the results of a retrospective cohort study of cancer incidence and mortality among emergency workers of the Chernobyl accident, for the follow-up period 1992-2009. The cohort selected for analysis consists of 67,568 emergency workers who worked in the Chernobyl exclusion zone in 1986-1987. External radiation whole-body absorbed dose varied from 0.

Comparing risk estimates following diagnostic CT radiation exposures employing different methodological approaches.

The current study has two aims: the first is to quantify the difference between radiation risks estimated with the use of organ or effective doses, particularly when planning pediatric and adult computed tomography (CT) examinations. The second aim is to determine the method of calculating organ doses and cancer risk using dose-length product (DLP) for typical routine CT examinations. In both cases, the radiation-induced cancer risks from medical CT examinations were evaluated as a function of gender and age.

Estimation of risk from medical radiation exposure based on effective and organ dose: how much difference is there?

The authors compare radiation risks of potential cancer following diagnostic radiation exposure evaluated with the use of organ and effective doses. Lifetime attributable risk values of CT scanning are estimated with the use of ICRP (Publication 103) risk models and Russian national medical statistics data. For populations under the age of 50, the risk evaluated using organ doses usually differs from that using effective doses by <30 %.

Risk of thyroid cancer among chernobyl liquidators.

After the Chernobyl accident in 1986, the "liquidators" or clean-up workers were among those who received the highest radiation doses to the thyroid from external radiation. Some were also exposed to radioiodines through inhalation or ingestion. A collaborative case-control study nested within cohorts of Belarusian, Russian and Baltic liquidators was conducted to evaluate the radiation-induced risk of thyroid cancer.

Systematic review and meta-analysis of circulatory disease from exposure to low-level ionizing radiation and estimates of potential population mortality risks.

Background: Although high doses of ionizing radiation have long been linked to circulatory disease, evidence for an association at lower exposures remains controversial. However, recent analyses suggest excess relative risks at occupational exposure levels.

Objectives: We performed a systematic review and meta-analysis to summarize information on circulatory disease risks associated with moderate- and low-level whole-body ionizing radiation exposures.

Radiation-epidemiological studies of thyroid cancer incidence in Russia after the Chernobyl accident (estimation of radiation risks, 1991-2008 follow-up period).

This study presents an analysis of the thyroid cancer incidence in the population of the most contaminated territories of Bryansk, Kaluga, Oryol and Tula oblasts affected by the Chernobyl accident. The follow-up period is 1991-2008, and the cohort size is 309 130 people. For that period 978 thyroid cancer cases were detected.

Leukemia incidence in the Russian cohort of Chernobyl emergency workers.

Of all potentially radiogenic cancers, leukemia, a type of cancer of the blood, has the highest risk attributable to ionizing radiation. Despite this, the quantitative estimation of radiation risk of a leukemia demands studying very large exposed cohorts, because of the very low level of this disease in unexposed populations and because of the tendency for its radiation risk to decrease with time. At present, the Japanese cohort of atomic bomb survivors is still the primary source of data that allows analysis of radiation-induced leukemia and the underlying dose-response relationship.

[Mortality among the liquidators of the Chernobyl accident: dose dependences and groups of the potential risk].

Dynamics of the mortality and the mortality radiation risks among male emergency workers of 1986-1987 years of entrance to the Chernobyl zone is analyzed. The average dose of external gamma-exposure for this cohort equals 128 mGy. The size of the cohort at the beginning of the follow-up in 1992 was 47820 persons.

[Investistigation of the role of heterogenety individual radiosensitivity in estimation of radiation indused ageing].

The influence of heterogeneity in individual radiosensitivity on estimation of ageing using survival curve is considered. Quadratic deviation of the rate of ageing from the true value in estimated by imitation modeling techniques. The Gompertz model for spontaneous mortality and gamma-frailty model for heterogeneity are used.

[Statistical methods for the analyses in clinical practice. Part 2. Survival analysis and multivariate statistics].

Statistical analysis is an integral component of clinical studies. The objective of the present paper is to assist clinicians in getting deeper insight into basic principles underlying different methods available for the statistical treatment of medical data without a detailed description of relevant mathematical calculations. The most popular and widely used methods of statistical analysis are considered with special reference to their practical application in clinical and experimental medicine.

Estimation of individualized radiation risk from chronic occupational exposure in Russia.

Internationally, the upper limit of acceptable individualized risk from occupational exposure for nuclear industry workers is determined by the death probability 10(-3) y(-1). The same risk value of 10(-3) y(-1) is established by the radiation safety standards currently in force in Russia. The United Nations Scientific Committee on the Effects of Atomic Radiation has proposed the formulas for estimating individualized risk of developing cancer with allowance for radiation dose, age at exposure, attained age, and sex.

Risk of thyroid cancer among Chernobyl emergency workers of Russia.

The presented paper deals with the thyroid cancer incidence in selected cohorts of emergency workers of Russia. In 1986-2003, a total of 87 cases of thyroid cancer were observed. Based on these data, a statistically significant increase in thyroid cancer incidence was found above the reference level for the male population of Russia, corresponding to a standardized incidence rate (SIR) of SIR = 3.

[Thyroid cancer incidence among Chernobyl emergency workers: follow-up period 1986-2003].

A vast amount of research articles devoted to the increase in childhood thyroid cancer incidence in the most contaminated by radionuclides territories of Belarus, Russia and Ukraine affected by the Chernobyl accident were published recent years. However, the amount of research studies of thyroid cancer incidence among the Chernobyl emergency workers (liquidators) is quite scanty. In the article results of the study of thyroid cancer incidence in the cohort of the Chernobyl liquidators (103427 persons) residing in 6 administrative regions of Russia (North-West, Volgo-Vyatsky, Central-Chernozemny, Povolzhsky, North-Caucasus and Urals) are described and discussed.

[Somatic mutagenesis at T-cell receptor locus in inhabitants of radiation polluted regions as a result of the Chernobyl disaster].

In the period of 2001-2004, frequency of cells bearing mutations at T-cell receptor (TCR) locus was assessed in 553 inhabitants of radiation polluted regions of the Russian Federation and 154 unexposed control persons. The inhabitants were divided into three groups according to age at the moment of the Chernobyl disaster and 137Cs pollution density: 1) in utero, 37-555 kBq/m2; 2) 0-14 years old, 20-555 kBq/m2; 3) 18 and more years old, highest 137Cs density (185 more than 555 kBq/m2). The most intense changes of the TCR-mutant cell frequency were observed in the group of persons exposed to ionizing radiation in utero.

[Cancer morbidity and mortality among the liquidators of the Chernobyl accident: estimation of radiation risks].

The work focuses on the results of the analysis of the cancer incidence among the Chernobyl emergency workers residing in Russia during 1991-2001. The analysis is based on the data for the cohort of male emergency workers from 6 regions of Russia including 55718 persons with documented external radiation doses in the range of 0.001-0.