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Biomedical subjects

V K Ivanov

Publications and source records attributed to V K Ivanov.

At least 19 recordsLinked to original sources
PubMed2006

Concept of optimisation of the radiation protection system in the nuclear sector: management of individual cancer risks and providing targeted health care.

The paper discusses the provision of targeted health care to nuclear workers in Russia based on radiation-epidemiological estimates of cancer risks. Cancer incidence rates are analysed for the workers of the Institute of Physical Power Engineering (the first nuclear installation in the world) who were subjected to individual dosimetric monitoring from 1950 to 2002. The value of excess relative risk for solid cancers was found to be ERR Gy(-1) = 0.24 (95% CI: -4.22; 7.96). It has been shown that 81.8% of the persons covered by individual dosimetric monitoring have potential attributive risk up to 5%, and the risk is more than 10% for 3.7% of the workers. Among the detected cancer cases, 73.5% of the individuals show an attributive risk up to 5% and the risk is in excess of 10% for 3.9% of the workers. Principles for the provision of targeted health care, given voluntary health insurance, are outlined.

Body Burden↗
PubMed2006

The role of intermediate state polarization in determination of vector properties of the ground state using multiphoton excitation.

We present a general theory for calculating the vector and geometrical properties of the multiphoton excitation of an arbitrary atomic or molecular system. The results are applied to study the influence of the polarization of the two-photon excited state, which is usually neglected, on the intensity of (2 + 1) resonant multiphoton ionization in atoms. Two examples of specific atomic systems of practical importance are presented: oxygen and chlorine. For some cases, the effect of the polarization of the pre-ionized state can be significant and must be properly treated.

Algorithms↗
PubMed2006

Radiation-epidemiological studies of thyroid cancer incidence among children and adolescents in the Bryansk oblast of Russia after the Chernobyl accident (1991-2001 follow-up period).

In this study, thyroid cancer incidence (follow-up period: 1991-2001) has been analyzed, including persons who were exposed as children at an age between 0 and 17 years and who are living in the Bryansk oblast, the worst contaminated area of Russia after the Chernobyl accident. According to the census of 1989, the population of this oblast comprises 375 thousand people. Thyroid doses from incorporated radioiodine isotopes -- both for the thyroid cancer cases and the study population -- were determined based on the official methodology approved by the Russian Scientific Commission on Radiation Protection. Between 1991 and 2001, a total of 199 thyroid cancer cases were diagnosed at cancer centers (the so-called oncological dispensaries) of the investigated regions. The performed analysis relies on medical and dosimetric information available from the Russian National Medical and Dosimetric Registry which was established after the Chernobyl accident. Diagnoses were confirmed histologically for 95% of the cases. The analysis described revealed statistically significant radiation risk only for those exposed as children at an age of 0-9 years. In this group, the standardized incidence ratio (the national incidence rate was used as a reference) in the considered time period is estimated to be 6.7 (5.1, 8.6 95%CI) and 14.6 (10.3, 20.2 95%CI) for girls and boys, respectively. The risk dependence on age at exposure has also been studied. It has been shown that the smaller the age the higher the risk. For girls whose age at exposure was 0-4 years, the excess relative risk per 1 Gy for the period 1991-2001 was 45.3 (5.2, 9,953 95%CI; with internal control) and 28.8 (4.3, 2,238 95%CI; with external control), respectively. For boys whose age at exposure was 0-9 years the corresponding excess relative risk per 1 Gy was 68.6 (10.0, 4,520 95%CI) and 177.4 (-276, 10(6) 95%CI), respectively. Dependence of radiation risk on time was studied, with the focus on two follow-up periods 1991-1996 and 1997-2001, respectively. In 1997-2001 the radiation risk is shown to decrease among girls, and increase among boys.

Adolescent↗
PubMed2006

The risk of radiation-induced cerebrovascular disease in Chernobyl emergency workers.

The paper deals with estimating radiation risks of non-cancer diseases of the circulatory system among the Chernobyl emergency workers based on data from the Russian National Medical and Dosimetric Registry. The results for the cohort of 61,017 people observed between 1986 and 2000 are discussed. These are essentially updated results for the similar cohort that was studied by authors earlier in 1986-1996. Newly discovered is the statistically significant dose risk of ischemic heart disease [ERR Gy = 0.41, 95% CI = (0.05; 0.78)]. Confirmation is provided for the existence of significant dose risks for essential hypertension [ERR Gy = 0.36, 95% CI = (0.005; 0.71)] and cerebrovascular diseases [ERR Gy = 0.45, 95% CI = (0.11; 0.80)]. In 1996-2000, the assessed ERR Gy for cerebrovascular diseases was 0.22 with 95% CI = (-0.15; 0.58). Special consideration is given to cerebrovascular diseases in the cohort of 29,003 emergency workers who arrived in the Chernobyl zone during the first year after the accident. The statistically significant heterogeneity of the dose risk of cerebrovascular diseases is shown as a function of the duration of stay in the Chernobyl zone: ERR Gy = 0.89 for durations of less than 6 wk, and ERR Gy = 0.39 on average. The at-risk group with respect to cerebrovascular diseases are those who received external radiation doses greater than 150 mGy in less than 6 wk [RR = 1.18, 95% CI = (1.00; 1.40)]. For doses above 150 mGy, the statistically significant risk of cerebrovascular diseases as a function of averaged dose rate (mean daily dose) was observed: ERR per 100 mGy d = 2.17 with 95% CI = (0.64; 3.69). The duration of stay within the Chernobyl zone itself, regardless of the dose factor, had little influence on cerebrovascular disease morbidity: ERR wk = -0.002, with 95% CI = (-0.004; -0.001). The radiation risks in this large-scale cohort study were not adjusted for recognized risk factors such as excessive weight, hypercholesterolemia, smoking, alcohol consumption, and others.

Cerebrovascular Disorders↗
PubMed2004

Solid cancer incidence among the Chernobyl emergency workers residing in Russia: estimation of radiation risks.

An analysis is presented of solid cancer incidence during 11 years of follow-up (1991-2001) of Chernobyl emergency workers residing in Russia. The analysis is based on data from the cohort of male emergency workers from 6 regions in Russia including 55718 persons with documented external radiation doses in the range of 0.001-0.3 Gy who worked within the 30 -km zone in 1986-1987. The mean age at exposure for these persons was 34.8 years and the mean external radiation dose 0.13 Gy. In the cohort 1370 cases of solid cancer were diagnosed and 3 follow-up periods were considered: 1991-1995, 1996-2001 and 1991-2001. The second follow-up period was chosen to allow for a minimum latency period of 10 years being characteristic of solid cancers. For risk assessment two control groups have been introduced, the first 'external' one representing incidence rates for corresponding ages in Russia in general, the second 'internal' one consisting of emergency workers. The risk estimates were based on spontaneous incidence rates of solid cancer. The estimated standardized incidence ratio (SIR) is in good agreement (95% CI) with that of the control. The values of excess relative risk per unit dose (ERR/Gy) for solid malignant neoplasms have been estimated to be 0.33 (95% CI: -0.39, 1.22) (internal control) for the follow-up period 1991-2001 and 0.19 (95% CI: -0.66, 1.27) for 1996-2001.

Chernobyl Nuclear Accident↗
PubMed2003

Thyroid cancer incidence among adolescents and adults in the Bryansk region of Russia following the Chernobyl accident.

Thyroid cancer incidence in the Bryansk region, the most contaminated area of Russia after the Chernobyl accident, is analyzed for the residents aged 15-69 y at the time of the accident (about 1 million persons according to the 1989 census) for the period from 1986 to 1998. Sex and age standardized incidence rates are presented and compared to the whole Russian population rates (SIR analysis). Also, a geographical correlation analysis is performed for incidence rates and mean thyroid doses at the district level, which provides a basis for preliminary estimation of radiation associated risks for the period 1991-1998 (to allow for a potential five year latent period). Thyroid doses were estimated based on the State official document "Methodology for reconstruction of dose from iodine radioisotopes in residents of the Russian Federation exposed to radioactive contamination as a result of the Chernobyl accident in 1986" (2000). Altogether, 1,051 thyroid cancer cases were detected in the Bryansk oncological dispensary from 1986 to 1998 and 769 from 1991 to 1998. Histological confirmation was available for 87% and 95% of these cases, respectively. Standardized incidence ratios (SIR) were 1.27 (95% CI = 0.92, 1.73) for the period 1986-1990 and 1.45 (95% CI = 1.20, 1.73) for the period 1991-1998 for males and 1.94 (95% CI = 1.70, 2.20) and 1.96 (95% CI = 1.82, 2.1) for females. The excess relative risk per 1 Gy (using external control) estimate for the period 1991-1998 was -0.4 (95% CI = -3.5, 2.7), -1.3 (95% CI = -2.8, 0.1) for males and females, respectively, and -0.6 (95% CI = -2.1, 0.8) for both sexes. Using internal controls, the excess relative risk (ERR(1Gy)) per unit dose of 1 Gy was found to be 0.7 with 95% CI (-2.3, 5.2) for males, -0.9 with 95% CI (-2.4, 0.8) for females and 0.0 with 95% CI (-1.4, 1.7) for males and females together. These results are discussed in the light of the quality of information available on thyroid cancer cases and screening campaigns carried out after the Chernobyl accident.

Adolescent↗
PubMed2003

[Incidence of post-Chernobyl leukemia and thyroid cancer in children and adolescents in the Briansk region: evaluation of radiation risks].

Leukemia (51: 1988-1998) and thyroid cancer (106: 1991-1998) incidence in children and adolescents after Chemobyl accident in Bryansk region was assessed. A significant increase over spontaneous incidence in the same category of population and during the same period was reported. Standardized thyroid cancer incidence for the region is 5.37 times the federal level (95% confidence intervals--4.40 and 6.49, respectively); the upward trend is significant. The same trend is characteristic of leukemia incidence/exposure dose correlation but is not significant. Standardized leukemia incidence is 1.04 times the federal level (95% confidence intervals--0.78% and 1.34, respectively), and tallies with the federal level, within the margin of error. The findings are clearly indicative of exposure to radiation being a factor of higher thyroid cancer incidence in children and adolescents in Bryansk region.

Adolescent↗
PubMed2002

Thyroid cancer incidence among liquidators of the Chernobyl accident. Absence of dependence of radiation risks on external radiation dose.

The increase of thyroid cancer incidence rate among children living in the Chernobyl contaminated territories of Belarus, Russia and Ukraine has widely been accepted. Our current work deals with thyroid cancer incidence in the cohort of liquidators (99024 persons) living in 6 regions of Russia: North-West, Volgo-Vyatsky, Central-Chernozemny, Povolzhsky, North-Caucasus and Urals. In the period 1986-1998, a total of 58 thyroid cancer cases were detected in this cohort. We found a statistically significant increase of the thyroid cancer incidence rate in liquidators as compared to the baseline (male population of Russia) level (SIR=4.33, 95% CI: 3.29; 5.60). It was demonstrated that there is no dependence of incidence rates due to external radiation exposure (ERR/Gy=-2.23, 95% CI: -4.67; 0.22).

Adolescent↗
PubMed2002

Studies of cancer risk among Chernobyl liquidators: materials and methods.

The current paper presents the methods and design of two case-control studies among Chernobyl liquidators-one of leukaemia and non-Hodgkin lymphoma, the other of thyroid cancer risk-carried out in Belarus, Estonia, Latvia, Lithuania and Russia. The specific objective of these studies is to estimate the radiation induced risk of these diseases among liquidators of the Chernobyl accident, and, in particular, to study the effect of exposure protraction and radiation type on the risk of radiation induced cancer in the low-to-medium- (0-500 mSv) radiation dose range. The study population consists of the approximately 10000 Baltic, 40000 Belarus and 51 000 Russian liquidators who worked in the 30 km zone in 1986-1987, and who were registered in the Chernobyl registry of these countries. The studies included cases diagnosed in 1993-1998 for all countries but Belarus, where the study period was extended until 2000. Four controls were selected in each country from the national cohort for each case, matched on age, gender and region of residence. Information on study subjects was obtained through face-to-face interview using a standardised questionnaire with questions on demographic factors, time, place and conditions of work as a liquidator and potential risk and confounding factors for the tumours of interest. Overall, 136 cases and 595 controls after receiving their consent were included in the studies. A method of analytical dose reconstruction has been developed, validated and applied to the estimation of doses and related uncertainties for all the subjects in the study. Dose-response analyses are underway and results are likely to have important implications to assess the adequacy of existing protection standards, which are based on risk estimates derived from analyses of the mortality of atomic bomb survivors and other high dose studies.

Baltic States↗
PubMed2001

Mortality among the Chernobyl emergency workers: estimation of radiation risks (preliminary analysis).

This paper presents results of the analysis of mortality among Chernobyl accident emergency workers who are resident in Russia. The analysis is based on information for the cohort of emergency workers (males) from six regions of Russia including 65,905 persons with documented external doses in the range 0.005-03 Sv. These data were gathered during the period 1991 to 1998 and cover a total of 426,304 follow-up person-y. In this period, 4,995 deaths occurred in the cohort under study. The mortality analysis was performed for four groups of causes of death (ICD-9 codes): (1) malignant neoplasms (140-239); (2) cardiovascular diseases (390-459); (3) injuries, poisoning and violent deaths, (800-999); and (4) the remainder (other than the above). The standardized mortality rate for groups 1, 3, and 4 is less than unity and varies from 0.6 to 0.9. For group 2 (death from cardiovascular diseases) the standardized mortality rate conforms with the control within 95% confidence intervals. The control was the mortality rate (males) for the corresponding ages in Russia in general and the internal control, the spontaneous mortality among emergency workers, derived from the equation of the observed and expected number of cases in the followed up cohort. Dose response of mortality was studied. Statistically significant radiation risks were obtained for mortality from malignant neoplasms (515 cases) and cardiovascular diseases (1,728 cases). The values of the excess relative risk per unit dose (ERR Sv(-1)) for malignant neoplasms and cardiovascular diseases are estimated as 2.11 (1.31, 2.92 95% CI) and 0.54 (0.18,0.91 95% CI) (for external control), 2.04 (0.45, 4.31 95% CI) and 0.79 (0.07, 1.64 95% CI) (for internal control), respectively. The risk of death from all noncancer causes is close to zero and not statistically significant.

Dose-Response Relationship, Radiation↗
PubMed2001

Cancer incidence among nuclear workers in Russia based on data from the Institute of Physics and Power Engineering: a preliminary analysis.

One group that has the potential to be exposed to radiation is workers in the nuclear industry. Results of a systematic medical follow-up and dosimetric monitoring of these workers can form the basis for a study of the relationship between cancer incidence and radiation dose. As part of such efforts in Russia, a major institution of the nuclear industry with an established medical care unit, archiving capabilities, and dosimetry department was selected: the Institute of Physics and Power Engineering (IPPE) in Obninsk. In the study, a comparative analysis of cancer incidence rates for the IPPE workers and for the general population of Russia in 1991-1997 was carried out. The subjects were the IPPE workers hired before 1981. This restriction was imposed to reduce the uncertainty associated with the possible latent period in the development of solid cancers. Thus the possibility of including persons who already had the disease at the time when they were hired was minimized. The analysis is based on information about 158 cancer cases, including 24 cancers in persons under individual dosimetric monitoring. A statistically significant excess in cancer incidence was found among the IPPE workers compared with a comparison population (the general population of Russia) for some types of cancers. The SIR values for all cancers (ICD-9: 140-208) is 0.93 (95% CI 0.76, 1.12) for males and 1.42 (95% CI 1.06, 1.87) for females. A statistically significant excess for all cancers was also observed for residents of Obninsk compared to the control comparison population. The corresponding SIR value was 1.20 (95% CI 1.12, 1.28) for males and 1.58 (95% CI 1.49, 1.69) for females. An important reason for the observed excess in cancer incidence compared to the control population may be the higher level of health care in the so-called nuclear cities of Russia which may have resulted in increased diagnosis and registration of cancers. A statistically significant dependence of the cancer incidence on the dose of ionizing radiation was not established. The excess relative risk per gray for all types of cancer was 0.91 (95% CI -2.75, 4.61) for males and 0.40 (95% CI -6.94, 7.83) for females. These estimates should be considered to be preliminary, as the number of cases considered in the analysis of the dose response is small (17 males and 7 females).

Cohort Studies↗
PubMed2000

Radiation-epidemiological analysis of incidence of non-cancer diseases among the Chernobyl liquidators.

The work is concerned with assessment of radiation risks for non-cancer disease among the Chernobyl liquidators from 1986 to 1996. As of 1 January 1999, the Russian National Medical and Dosimetric Registry contains medical and dosimetric data for 174,000 liquidators. The cohort of 68,309 liquidators for whom best verified medical data are available is discussed. The dose dependency of incidence of non-cancer diseases was estimated by the cohort method and using the software package Epicure. For some classes of non-cancer diseases among liquidators, statistically significant estimates of radiation risk were derived for the first time. The highest excess relative risk per 1 Gy was found for cerebrovascular diseases; ERR Gy(-1)=1.17 at the 95% confidence interval (0.45; 1.88).

Adolescent↗
PubMed2000

[Dynamics of morbidity among liquidators of Chernobyl nuclear power station accident].

The article represents data on distribution of liquidators in Russian State Medical Dosimetry Register according to account categories, residing territories (regions of Russia), age, sex, dose groups, coverage by medical examinations and health groups. During 1991-1996 the liquidators demonstrated higher occurrence of endocrine, neurologic and sensory, circulatory, digestive and malignant diseases.

Adult↗
PubMed2000

A case-control analysis of leukemia in accident emergency workers of Chernobyl.

We estimated the radiation-induced risk of leukemia in 162,684 Chernobyl accident emergency workers (EWs) using the data of the Russian National Medical and Dosimetric Registry (RNMDR). A system was established for the collection and verification of data in 55 cases of leukemia from 1986 to 1995. The principal analysis included 41 leukemia cases that occurred more than 2 years after the first exposure to radiation. The case-control methodology was used to evaluate the risk of leukemia associated with various factors. Radiation dose, effective exposure dose rate, date of entry into the Chernobyl zone (ChZ), and the duration of stay in the zone were used as risk factors. The relationship between the date of entry and the duration of stay in the zone was investigated. All cases of leukemia, excluding chronic lymphocytic leukemia (CLL), were analyzed. An analysis was also performed on all EWs and on the EWs who worked in the zone from 1986 to 1987 (EWs of 1986 to 1987). No significant association was found between the risk of leukemia and the factors we investigated. Nevertheless, the relative risk estimates for leukemia, excluding CLL, were greater than the value for all leukemia and were greater than one. The estimated excess relative risk (ERR) per Gy was greater for all EWs [ERR = 1.33, 95% confidence interval (CI): -6.25, 8.90 for all leukemia, and ERR = 15.59, 95% CI: -24.92, 56.11 for leukemia, excluding CLL] compared with EWs of 1986 to 1987 (ERR = 0.28, 95% CI: -5.84, 7.41 for all leukemia, and ERR = 9.43, 95% CI: -20.0, 38.86 for leukemia, excluding CLL).

Case-Control Studies↗
PubMed1999

Dynamics of thyroid cancer incidence in Russia following the Chernobyl accident.

This paper presents an analysis of thyroid cancer incidence in the territories of Russia most contaminated after the Chernobyl accident. In the work, data on incidence in the Bryansk, Kaluga, Orel and Tula regions (5298000 persons) are used. Altogether, 2599 cases of thyroid cancer are considered from 1982 to 1995. Of them, 143 cases were among the population who were children and adolescents at the time of the accident in 1986. The work uses the approach based on comparison of distributions of thyroid cancer cases by age at diagnosis and age at exposure. It has been shown that since 1991 the age structure of the incidence has changed significantly with a growing proportion of cases among children and adolescents. The change in the structure occurred due to the radiation factor, specifically as a result of exposure of thyroid to incorporated 131I. It has been shown that the standardised incidence ratio (SIR) of thyroid cancer among children who were 0-4 years at exposure in 1991-6 was 6 to 10 times higher than among adults. On the average, SIR for children and adolescents at the time of exposure is about three times higher than in adults.

Adolescent↗
PubMed1998

Cancer incidence among liquidators of the Chernobyl accident: solid tumors, 1986-1995.

The paper considers information about cancer incidence (solid tumors) among liquidators of the Chernobyl accident, which occurred in April 1986. The information was accumulated in the Russian National Medical and Dosimetric Registry (RNMDR) in the period from 1986 to early 1996. The RNMDR contains individual dosimetric and annual check-up data on liquidators resident in Russia. This paper presents results for male liquidators who had no oncological diseases before arrival to the 30-km zone and for whom the following information was available: confirmed dose of external radiation, birth date, date of arrival to the 30-km zone, time spent in the 30-km zone, and results of medical check-ups. The number of liquidators under study is 114,504, i.e., about 68% of all those registered in the RNMDR. The average dose of the studied cohort is 108 mGy; the average age at first arrival to the 30-km zone is 34.3 y; the total number of person-y is 797,781. The cohort of liquidators is briefly characterized. Cancer incidence in liquidators is compared to that of the population of Russia as a whole by calculating standardized incidence ratio (SIR). The values of SIR with 95% confidence intervals for all solid tumors and malignant neoplasms of the digestive system were 1.23 (1.15; 1.31) and 1.11 (1.01; 1.24), respectively. Assessment of radiation risks for the same classes of diseases has revealed a statistically significant increase in cancer incidence with external radiation dose. This study also shows that statistically significant excesses in the incidence of malignant neoplasms of the respiratory system have not been observed.

Adolescent↗
PubMed1997

Leukaemia and thyroid cancer in emergency workers of the Chernobyl accident: estimation of radiation risks (1986-1995).

This work focuses on the direct epidemiological assessment of the risks of radiation-induced leukaemia and thyroid cancer in emergency workers (EW) after the Chernobyl accident. The Russian National Medical Dosimetric Registry (RNMDR) contains data for 168,000 EW as of January 1, 1996. The analysis relates to 48 leukaemias and 47 thyroid cancers, diagnosed and verified. Radiation risks are estimated by comparing the EW data with national data for a male population of the same age distribution. For leukaemia, an excess relative risk per Gy (ERR/Gy) of 4.30 (95% CI: 0.83, 7.75) is obtained, while the excess absolute risk per 10(4) person-years (PY) Gy (EAR/10(4)PY Gy) is found to be 1.31 (95% CI: 0.23, 2.39); for thyroid cancer an ERR/Gy of 5.31 (95% CI: 0.04, 10.58) is obtained, and an EAR/10(4)PY Gy of 1.15 (95% CI: 0.08, 2.22).

Adult↗