EPR dose reconstruction of two Kazakh villages near the Semipalatinsk nuclear test site

ArticleinApplied Magnetic Resonance 22(3):347-356 · September 2002with11 Reads
DOI: 10.1007/BF03166116
Electron paramagnetic resonance (EPR) dose reconstruction has been performed on archived tooth samples from residents of two villages near the Semipalatinsk nuclear test site in Kazakstan. The context of this work is a large multidisciplinary study of thyroid disease prevalence and radiation dose among long-term residents of villages near that nuclear test site, in which EPR is used for biodosimetric validation of the gamma-ray component of dose reconstruction algorithms applied to the data for various villages whose residents were exposed to radioactive fallout during 1949–1962, the period of above-ground atomic bomb testing. The tooth samples, nine from the village of Kainar and 23 from the village of Znamenka, were extracted in 1964 and 1967, respectively, and stored indoors in closed boxes in Semipalatinsk. According to provided information, some time in the past, the teeth from Kainar were heated to 80°C for one day. Experiments carried out on 12 teeth from US sources to determine the effects of long-term storage and heat treatment found that EPR assay findings were not compromised for storage times less than 35 years and annealing at temperatures below 200°C. For tooth enamel samples prepared from molars and premolars the average reconstructed gamma dose was 390±70 mGy for Kainar residents and 95±40 mGy for Znamenka residents.
    • "Therefore, individuals who had teeth formation during the radioactive releases (1945–1949) accumulated a much higher amount of 90 Sr than other exposed individuals in that population . This finding suggests the ability of EPR dose reconstruction in teeth collected from donors of different ages to determine both the doses and type of radionuclide intake (Romanyukha et al., 2002a, b). EPR dose reconstruction with teeth from Mayak nuclear workers showed relatively good agreement between EPR derived doses and individual dose monitoring (Romanyukha et al., 2000), depending upon the type of badge and specific plant at Mayak (Wieser et al., 2006b ). "
    [Show abstract] [Hide abstract] ABSTRACT: The requirements for biodosimetric techniques used at long times after exposure, i.e., 6 months to more than 50 years, are unique compared to the requirements for methods used for immediate dose estimation. In addition to the fundamental requirement that the assay measures a physical or biologic change that is proportional to the energy absorbed, the signal must be highly stable over time to enable reasonably precise determinations of the absorbed dose decades later. The primary uses of these biodosimetric methods have been to support long-term health risk (epidemiologic) studies or to support compensation (damage) claims. For these reasons, the methods must be capable of estimating individual doses, rather than group mean doses. Even when individual dose estimates can be obtained, inter-individual variability remains as one of the most difficult problems in using biodosimetry measurements to rigorously quantify individual exposures. Other important criteria for biodosimetry methods include obtaining samples with minimal invasiveness, low detection limits, and high precision. Cost and other practical limitations generally prohibit biodosimetry measurements on a large enough sample to replace analytical dose reconstruction in epidemiologic investigations. However, these measurements can be extremely valuable as a means to corroborate analytical or model-based dose estimates, to help reduce uncertainty in individual doses estimated by other methods and techniques, and to assess bias in dose reconstruction models. There has been extensive use of three biodosimetric techniques in irradiated populations: EPR (using tooth enamel), FISH (using blood lymphocytes), and GPA (also using blood); these methods have been supplemented with luminescent methods applied to building materials and artifacts. A large number of investigations have used biodosimetric methods many years after external and, to a lesser extent, internal exposure to reconstruct doses received from accidents, from occupational exposures, from environmental releases of radioactive materials, and from medical exposures. In most applications, the intent has been to either identify highly exposed persons or confirmed suspected exposures. Improvements in methodology, however, have led many investigators to attempt quantification of whole-body doses received, or in a few instances, to estimate organ doses. There will be a continued need for new and improved biodosimetric techniques not only to assist in future epidemiologic investigations but to help evaluate the long-term consequences following nuclear accidents or events of radiologic terrorism.
    Full-text · Article · Jul 2007
    • "Our preliminary results might be compared to the work of Romanyukha et al. [12] , who found an average reconstructed gamma dose of 390±70 mGy for nine tooth enamel samples of eight Kainar residents prepared from teeth extracted in 1964. "
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