Assessment of Occupational Exposure and Individual Radio-Sensitivity in People Subjected to Ionizing Radiation
The estimation of accumulated radiation doses in people professionally exposed to ionizing radiation was performed using methods of biological (chromosomal aberrations frequency in lymphocytes) and physical (radionuclides analysis in urine, whole-body radiation meter, individual thermoluminescent dosimeters) dosimetry. A group of 84 "A" category employees after their work in the territory of former Semipalatinsk test site (Kazakhstan) was investigated. The dose rate in some funnels exceeds 40 μSv/h. After radionuclides determination in urine using radiochemical and WBC methods, it was shown that the total effective dose of personnel internal exposure did not exceed 0.2 mSv/year, while an acceptable dose limit for staff is 20 mSv/year. The range of external radiation doses measured with individual thermo-luminescent dosimeters was 0.3-1.406 µSv. The cytogenetic examination showed that chromosomal aberrations frequency in staff was 4.27±0.22%, which is significantly higher than at the people from non-polluting settlement Tausugur (0.87±0.1%) (р ≤ 0.01) and citizens of Almaty (1.6±0.12%) (р≤ 0.01). Chromosomal type aberrations accounted for 2.32±0.16%, 0.27±0.06% of which were dicentrics and centric rings. The cytogenetic analysis of different types group radiosensitivity among «professionals» (age, sex, ethnic group, epidemiological data) revealed no significant differences between the compared values. Using various techniques by frequency of dicentrics and centric rings, the average cumulative radiation dose for group was calculated, and that was 0.084-0.143 Gy. To perform comparative individual dosimetry using physical and biological methods of dose assessment, calibration curves (including own ones) and regression equations based on general frequency of chromosomal aberrations obtained after irradiation of blood samples by gamma-radiation with the dose rate of 0,1 Gy/min were used. Herewith, on the assumption of individual variation of chromosomal aberrations frequency (1–10%), the accumulated dose of radiation varied 0-0.3 Gy. The main problem in the interpretation of individual dosimetry results is reduced to different reaction of the objects to irradiation - radiosensitivity, which dictates the need of quantitative definition of this individual reaction and its consideration in the calculation of the received radiation dose. The entire examined contingent was assigned to a group based on the received dose and detected cytogenetic aberrations. Radiosensitive individuals, at the lowest received dose in a year, showed the highest frequency of chromosomal aberrations (5.72%). In opposite, radioresistant individuals showed the lowest frequency of chromosomal aberrations (2.8%). The cohort correlation according to the criterion of radio-sensitivity in our research was distributed as follows: radio-sensitive (26.2%) — medium radio-sensitivity (57.1%), radioresistant (16.7%). Herewith, the dispersion for radioresistant individuals is 2.3; for the group with medium radio-sensitivity — 3.3; and for radio-sensitive group — 9. These data indicate the highest variation of characteristic (reactions to radiation effect) in the group of radio-sensitive individuals. People with medium radio-sensitivity show significant long-term correlation (0.66; n=48, β ≥ 0.999) between the values of doses defined according to the results of cytogenetic analysis and dose of external radiation obtained with the help of thermoluminescent dosimeters. Mathematical models based on the type of violation of the radiation dose according to the professionals radiosensitivity level were offered.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1131489Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 541
 I. B. Mosse, “Problems of Evaluation of Genetic Effects of Ionizing Radiation in Man,” in Proceedings Petro Mohyla Black Sea State University. Avg : Technological safety, vol. 116, no. 103, pp. 4-8, 2009.
 C. Mothersill, C. Seymour, “Relevance of radiation-induced bystander effects for environmental risk assessment” in Radiation Research, vol. 155, no. 6, Review, pp. 759-767, 2001.
 L. H. Thompson, “Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: The molecular choreography,” in Mutation Research/Reviews in Mutation Research, vol. 751, no. 10-12, pp. 158-246, 2012.
 M. Fenech, “Current status, new frontiers and challenges in radiation biodosimetry using cytogenetic, transcriptomic and proteomic technologies,” in Radiation Measurements, vol. 46, no. 9, pp. 737-741, 2011.
 Institute of Radiation Safety and Ecology, Methodical recommendations pretreatment urine samples for gamma - spectrometric analysis, beta - spectrometric analysis and determination of 3H radiochemical analysis by definition 90Sr, 239 +240 Pu, Kurchatov, 2010.
 International Atomic Energy Agency, Methods for Assessing Occupational Radiation Doses Due Intake of Radionuclides, Safety Report series, no. 37, Vienna: IAEA, 2004.
 International Atomic Energy Agency, Indirect Methods for Assessing Radionuclides Causing Occupational Exposure, Safety Reports Series, no. 18, Vienna: IAEA, 2000.
 International Comission on Radiological Protection, Individual Monitiring for Internal Exposure of Workers, Publication no. 78, 3-4, Oxford: Elsevier Sccience, 1997.
 International Atomic Energy Agency, Cytogenetic Analysis for Radiation Dose Assessment, Technical Reports Series no. 405, Vienna: IAEA, 2001.
 P. S. Moorhead, P. C. Nowell, W. J. Mellman, D. M. Battips, D. A. Hungerford, “Chromosome preparations of leucocytes cultured from human peripheral blood,” in Experimental Cell Research, vol. 20, pp. 613-616, 1960.P. F. Rokitsky, Introduction to statistical genetics, Minsk: High School, 1978, pp. 80-141.
 O. G. Cherednichenko, E. G. Gubitskaya, M. M. Bitenova, S. N. Lukashenko, A. L. Pilugina, “Assessment of occupational exposure and individual radiosensitivity in people exposed to radiation using methods of physical and biological dosimetry,” in Ecology & Safety, vol. 8, pp. 487-495, 2014.
 D. C. Lloyd, A. A. Edwards, A. Leonard, “Frequences of chromosomal aberaions induced in human blood lymphocetes by low doses X-rays,” in International Journal of Radiation Biology, vol. 53, pp. 49-55, 1998.
 International Atomic Energy Agency, Cytogenetic Analysis for Radiation Dose Assessment, Technical Reports Series no. 405. Vienna: IAEA, pp. 68-83, 2014.
 A.V.Rubanovich, G.P. Snigiryova, V.A. Shevchenko, E.A. Akaeva, G.I. Kuznetsova, I.N. Nilova, E.L. Iofa, T.V. Yelisova, “The Theory and Practice of Constructing Calibration Curves in Biodozimetry,” in Radiation Biology. Radioecology, vol. 46, no. 4, pp. 447-456, 2006.
 V. A. Vinnikov, E. A. Ainsbury, D. C. Lloyd, N. A. Maznyk, K. Rothkamm, “Difficult cases for chromosomal dosimetry: Statistical considerations” in Radiation Measurements, vol. 46, no. 9, pp. 1004-1008, 2011.
 V. A. Vinnikov, E. A. Ainsbury, N. A.Maznyk, D. C. Lloyd, K. Rothkamm, “Limitations associated with analysis of cytogenetic data for biological dosimetry,” in Radiat Res., vol.174, no. 3, pp. 403-414, 2010.
 R. H. Crespo, M. M. Domene, M. J. Rodríguez, “Biodozimetry and assessment of radiation dose,” in Practical Oncology & Radiotherapy, vol. 16, no. 4, pp. 131-137, 2011.
 I. I. Pelevina, A. V. Aleshchenko, M. M. Antoshina, O. V. Kudryashova, N. I. Ryabchenko, A. V. Akleev, “A change in the radiosensitivity of human blood lymphocytes after irradiation in small doses,” in Radiation Biology. Radioecology. no. 5, pp. 481-487, 2012.
 E. E.Kovalev, O. A. Smirnova, “Estimation of radiation risk based on the concept of individual variability of radiosensitivity,” AFRRI Contact Report № 96—1, Bethesda, Maryland, USA, pp.185-202, 1996.
 G. P.Snigiryova, N. N. Novitskaya, “Possibility of cytogenetic methods for examination of people exposed as a result of nuclear explosions on the Semipalatinsk test site,” Bulletin of the Russian Center for Public Health, Ministry of Health of the Russian Federation, no. 11, 2011, http://vestnik.rncrr.ru/vestnik/v11/papers/snigir _v11.htm, accessed on 15/08/2012.