Oncological Death Rate Depending on Doses of Irradiation
The Investigation of the Incidence Rate and Structure of Oncological Mortality Dose Ratio in the Personnel of Siberian Chemical Plant
Tech Area / Field
- MED-DIS/Disease Surveillance/Medicine
- ENV-MRA/Modelling and Risk Assessment/Environment
3 Approved without Funding
A.I. Burnazyan Federal Medical and Biophysical Center, Russia, Moscow
- Seversk Biophysics Research Center, Russia, Tomsk reg., Seversk
- US Department of Health & Human Services / National Institute of Health / National Cancer Institute, USA, MD, Bethesda\nDuke University / Center for Demographic Studies, USA, NH, Durham
Project summaryThe modern assessments of risk of the radiation induced cancer are based on epidemiological examinations of consequences of an acute exposition of the population of Japan at atomic explosions in Hiroshima and Nagasaki, and also on examinations of the patients exposed to the radiation in the therapeutic and diagnostic purposes. It was fixed, that the effect of the irradiation to doses from moderate up to major ones increases the cancer risk in the majority of organs.
For the population, the risk assessments for all kinds of solid cancers, and also leukemia are exact enough: even at rather low doses (0.2-0.5 Gy) the dependence of an induction of a cancer on a level of doses is found. The dose - effect ratio for solid cancers is well compounded with linear model in a restricted range of doses, though it is supposed, that the curve is bent at ultrahigh and low doses.
The greatest scientific and practical interest is presented by risk assessments of the systematic irradiation to doses exceeding tolerance levels in conditions of prolonged exposure. Such form of an exposure took place in conditions of professional work at the plants of an atomic industry including that at SCP.
Now there are not enough direct proofs of the cancer induction by the irradiation to low doses or at low dose rate. The results of examinations of separate cohorts of the nuclear plant workers in the USA and Canada, who were exposed to the radiation of the chronic doses of 30-50 mSv, are discordant. In some cases, the proofs of padding cases of all cumulative aspects of cancer are obtained, in other cases, the excess of cases of a leukemia is only detected, in third cases, the exuberant incidence rate of cancer is not generally detected. The most convincing data are obtained at analysis of the joint cohort of the professional workers of the USA, Canada and the Great Britain. Statistically reliable augmentation is revealed only for leukemias (Cardis generalization). The cancerogenic effects of an internal radiation are known even less. The data on cancerogenic risk of the irradiation from 131I, 222Rn and 239Pu are published.
Therefore the doubtless scientific and practical value is attributed to the deriving new data about cancerogenic effects of external and internal irradiation in the personnel. The examinations with the purposes of ISTC will allow to increase the accuracy of assessments of cancerogenic risk of low doses of the external, internal and combined radiation exposure of the human.
The undoubtedly important source for the evaluation of cancerogenic consequences can be provided by the data on radiation exposure of the personnel of the Siberian chemical plant, who have begun to work in 1950th. SCP is the second largest radiochemical enterprise in the former USSR (after the "Mayak” plant).
In the first years of the plant activities, the excess of regulated doses of external and internal radiation has took place. Cumulative doses of the external radiation in 1950th - 1960th in separate shops have made 500-1000 mSv.
Alongside with the scientific significance of deriving the new information on dependence of incidence and structure of the mortality of the personnel from a radiation induced cancer at an exposure to low doses, there is an actual problem of the information security of the atomic industry plant workers. One of consequences of the extreme security limitation of the occupational radiation information is the fact that the developed Norms of Radiation Safety (NRB) will not emanate from results of epidemiological matters.
The purpose of the Project is the examination of incidence rate and structure of the oncologic mortality of the personnel of the plants of the Siberian chemical combine in dependence on doses of the exposure to the ionizing radiation.
In the Project, the epidemiological materials on the exposure and health of the personnel of three factories of the Siberian chemical plant will be surveyed. The mortality with abjection of oncological mortality results to the criterion of the health safety. The oncological mortality is recognized as the most informative and social - significant parameter of health damage under the conditions of the constant life under the radiation risk.
During performance of the Project, it is supposed anew to reconsider an actual materials cumulated for many years, to treat them applying modern methods of analysis of dose - effect dependence, to supply new data, to structurize the dosimetric health monitoring data bank of the workers of an industrial reactor, radiochemical and plutonium factories.
To reach the formulated purpose, the following primal tasks will be solved:
1. Assessment of exposure doses of the personnel of an industrial reactor, radiochemical and plutonium factories basing on the archival data and newly obtained results.
2. Assessment of the mortality of the personnel in a time dependence of entering on work and cumulative dose for all terms of work basing on the archival and newly obtained data.
3. Building databases on exposure levels and mortality of the personnel of reactor, radiochemical and plutonium factories of SCP.
4. Assessment of oncological mortality risk of the personnel of the factories with various aspects of radiation: external, internal or combined one.
As a result of performance of the Project the new data having scientific and practical value will be obtained:
- earlier fixed doses of a external and internal radiation of the personnel during operation of the factories will be verified;
- The levels and structure of an oncologic mortality of the personnel of the SCP factories with various dose of external, internal and combined exposure within a long-lived span (45 years) are estimated in dynamics;
- The levels of doses which do not invoke tumoral effects are determined, as well as the levels of doses, at which minimum - possible tumoral effects at the personnel of the miscellaneous SCP factories would arise;
- The basis of dosimetric epidemiological monitoring is built for storage and analysis of the information;
- The hazards for oncological mortality of the personnel for various aspects of the irradiation are estimated.
On results of performance of the Project, following products will be prepared:
1. Monograph on "Cancer at the workers of professional radiation exposure factories of Siberian chemical plant. Theoretical and applied aspects of the problem".
2. The bank of the primary data on both the level and the structure of the oncologic mortality and exposure doses of the personnel of the basic factories of the Siberian chemical plant is built.
Within the framework of the fulfilled Project the materials of perennial health monitoring, radiation hygienic and epidemiological examinations of an oncologic mortality of the personnel of three basic factories of the Siberian chemical plant (industrial reactor, radiochemical and plutonium factories) will be generalized. The examinations will be fulfilled by the leading scientists and experts of the State Research Center - Institute of biophysics, Seversk Biophysics Research Center. Foreign collaborators will realize arguing results of examinations and information interchange on annual conferences.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
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