WorldWideScience

Sample records for background radiation dose

  1. Radiation dose in the high background radiation area in Kerala, India.

    Science.gov (United States)

    Christa, E P; Jojo, P J; Vaidyan, V K; Anilkumar, S; Eappen, K P

    2012-03-01

    A systematic radiological survey has been carried out in the region of high-background radiation area in Kollam district of Kerala to define the natural gamma-radiation levels. One hundred and forty seven soil samples from high-background radiation areas and five samples from normal background region were collected as per standard sampling procedures and were analysed for (238)U, (232)Th and (40)K by gamma-ray spectroscopy. External gamma dose rates at all sampling locations were also measured using a survey meter. The activities of (238)U, (232)Th and (40)K was found to vary from 17 to 3081 Bq kg(-1), 54 to 11976 Bq kg(-1) and BDL (67.4 Bq kg(-1)) to 216 Bq kg(-1), respectively, in the study area. Such heterogeneous distribution of radionuclides in the region may be attributed to the deposition phenomenon of beach sand soil in the region. Radium equivalent activities were found high in several locations. External gamma dose rates estimated from the levels of radionuclides in soil had a range from 49 to 9244 nGy h(-1). The result of gamma dose rate measured at the sampling sites using survey meter showed an excellent correlation with dose rates computed from the natural radionuclides estimated from the soil samples. PMID:21515614

  2. Profiles of comprehensive dose to population in the high background radiation area in Chhattrapur, Odisha, India

    International Nuclear Information System (INIS)

    A study of the profiles of radiation dose due to natural radioactivity to the populations inhabiting in the High Background Radiation Area (HBRA) of the monazite bearing region in Odisha has been carried out by radiation monitoring of twenty four villages in this region. Comprehensive effective dose was computed taking all the path routes of exposure into consideration; the average effective dose was 4.7±1.0 mSv/y which ranged between 1.4±0.2-6.3±1.3 mSv/y. The contributions of terrestrial radiation, inhalation of radon, thoron progenies and ingestion of food and water to the total dose was 51%, 28% and 13%, respectively. (author)

  3. Natural background radiation and estimation of gonadal dose rate of population of Chittagong region

    Energy Technology Data Exchange (ETDEWEB)

    Mostofa, M.N.; Ahmed, J.U. (Chittagong Univ. (Bangladesh). Dept. of Physics); Ahmed, R.; Ishaque, A.M. (Nuclear Medicine Center, Chittagong (Bangladesh)); Ahmed, K. (Institute of Nuclear Medicine, Dacca (Bangladesh))

    1981-07-01

    A survey was made on the background radiation to estimate the gonadal dose rate in the district of Chittagong from the year 1978 to 80. This was done with the help of a calibrated Nuclear Chicago transistorized survey meter. The measurements were made in different types of dwellings and occupational buildings constructed with wood, straw/bamboo, tin/bamboo, tin/brick and single and multistoried buildings of brick and concrete. For measurement of outdoor radiation the investigating areas taken were the roads, fields and the Karnafuly river. The variation in the population dose rate as well as gonadal dose rate were observed in different types of dwellings and occupational buildings including outdoors. The average population dose rate including cosmic ray intensity was found to be 172.41+-8.61 mrad/year. Thus, the annual gonadal dose rate due to gamma radiation was found to be 137.92+-6.89 mrad/year.

  4. Background levels and radiation dose yield of o-tyrosine in chicken meat

    International Nuclear Information System (INIS)

    The measurement of o-tyrosine levels in poultry meat is a potential method for postirradiation dosimetry of poultry. The validity of using o-tyrosine for this purpose has not yet been established. As part of the validation process, the o-tyrosine content in unirradiated chicken meat, the radiation dose response curve, and the effects of postirradiation storage on o-tyrosine levels are examined. In 18 individual samples, the mean background level of o-tyrosine was 0.18 +/- 0.11 ppm (wet weight, 70% moisture), and the most frequent background level (60% of the cases) was between 0.05 and 0.15 ppm (wet weight, 70% moisture). In pooled samples of 10 chickens, the mean background level was 0.12 +/- 0.03 ppm (wet weight, 70% moisture). The levels were not significantly affected by storage at 5 degrees C (7 d) or by freezing the sample. The radiation dose response curve was linear within the dose range studied (0 to 10 kGy), with a slope of 0.127 + 0.003 ppm (wet weight)/kGy. Although there was some variation in the intercept (0.132 + 0.013), the slope was the same in all samples tested. Postirradiation storage at either 4 or 8 degrees C until spoilage did not affect the levels of o-tyrosine. These data indicate that o-tyrosine level may be useful for determining the absorbed dose in chicken meat gamma-irradiated to doses greater than 0.6 kGy. Further validation studies are continuing

  5. Estimation of collective effective dose due to natural background radiation in Egypt

    Science.gov (United States)

    Henaish, B. A.; Tawfik, A. A.; Abu Zaid, H.; Gomaa, M. A.

    1994-07-01

    During the last few years, worldwide attention has been directed towards the estimation of natural background radiation levels. Several environmental monitoring networks have been established for systematic data collection and exchange of information.In the present study, measurements of annual effective dose from terrestrial γ-rays are carried out at pre-selected sites within several Egyptian governorates by using a calibrated gas-filled GM-detector connected to a microcomputer system. Contribution of the secondary cosmic-rays, which is of prime importance at sea level, is achieved by carrying out computation based on theoretical considerations.Terrestrial effective dose in Egypt is found to be between 106 and 371 μSv/yr, meanwhile the computed cosmic rays contribution is 260-296 μSv/yr. Accordingly, the annual collective effective dose due to natural background radiation is about 27,253 Man Sv for the last Egyptian population count (1989) considering 0.8 and 0.2 indoor and outdoor occupancy factors.

  6. Effective doses of background radiation in the Almaty and the Kazakhstan nuclear sites areas

    International Nuclear Information System (INIS)

    The comparative results for determination of partial effective doses from each kind of ionizing radiation and all pathways of radionuclides intakes of Almaty city population, and localities adjoining to nuclear test sites (Lira and Azgir), as well as Semipalatinsk test site (STS). Results of effective dose calculations are evidencing about absence of considerable influence of tests on the sites on the natural radiation dose loads and about some exceeding of effective dose in Almaty above effective doses in the sites' areas. Artificial radionuclides contribution of the sites areas (beside STS) does not exceeds the level of global fallout in Almaty

  7. Genetic background modulates lncRNA-coordinated tissue response to low dose ionizing radiation

    International Nuclear Information System (INIS)

    Long noncoding RNAs (lncRNAs) are emerging as key regulators of diverse cell functions and processes. However, the relevance of lncRNAs in the cell and tissue response to ionizing radiation has not yet been characterized. Here we used microarray profiling to determine lncRNA and mRNA expression in mammary glands of BALB/c and SPRET/EiJ mice after low-dose ionizing radiation (LDIR) exposure. We found that unirradiated mammary tissues of these strains differed significantly in baseline expressions of 290 lncRNAs. LDIR exposure (10 cGy) induced a significant change in the expression of many lncRNAs. The vast majority of lncRNAs identified to be differentially expressed after LDIR in either BALB/c or SPRET/EiJ had a significantly correlated expression pattern with at least one LDIR responsive mRNA. Functional analysis revealed that the response to LDIR in BALB/c mice is highly dynamic with enrichment for genes involved in tissue injury, inflammatory responses, and mammary gland development at 2, 4, and 8 weeks after LDIR, respectively. Our study demonstrates that genetic background strongly influences the expression of lncRNAs and their response to radiation and that lncRNAs may coordinate the tissue response to LDIR exposure via regulation of coding mRNAs

  8. Doses and risks from uranium are not increased significantly by interactions with natural background photon radiation.

    Science.gov (United States)

    Tanner, R J; Eakins, J S; Jansen, J T M; Harrison, J D

    2012-08-01

    The impact of depleted uranium (DU) on human health has been the subject of much conjecture. Both the chemical and radiological aspects of its behaviour in the human body have previously been investigated in detail, with the radiological impact being assumed to be linked to the alpha decay of uranium. More recently, it has been proposed that the accumulation in tissue of high-Z materials, such as DU, may give rise to enhanced local energy deposition in the presence of natural background photon radiation due to the high photoelectric interaction cross sections of high-Z atoms. It is speculated that, in addition to producing short-range photoelectrons, these events will be followed by intense Auger and Coster-Kronig electron emission, thereby causing levels of cell damage that are unaccounted for in conventional models of radiological risk. In this study, the physical and biological bases of these claims are investigated. The potential magnitudes of any effect are evaluated and discussed, and compared with the risks from other radiological or chemical hazards. Monte Carlo calculations are performed to estimate likely energy depositions due to the presence of uranium in human tissues in photon fields: whole body doses, organ doses in anthropomorphic phantoms and nano-/micro-dosimetric scenarios are each considered. The proposal is shown generally to be based on sound physics, but overall the impact on human health is expected to be negligible.

  9. Determination of Absorbed and Effective Dose from Natural Background Radiation around a Nuclear Research Facility

    Directory of Open Access Journals (Sweden)

    M. A. Musa

    2011-01-01

    Full Text Available Problem statement: This study presents result of outdoor absorbed dose rate and estimated effective dose from the naturally occurring radionuclides 232Th and 238U series 40K, around a Nuclear Research Reactor at the Centre for Energy Research and Training (CERT, Zaria, Nigeria. Approach: A high-resolution in situ ?-ray spectrometry was used to carry out the study. CERT houses a 30Kw Research Reactor and other neutron and gamma sources for Research and Training. Results: The values of absorbed dose rate in air for 232Th, 238U and 40K range from 8.2 ± 2.5-24.5 ± 3.6 nGy h?1, 1.9 ± 1.2-4.6 ± 2.5 nGy h?1 and 12.2 ± 5-38 ± 6.7n Gy h?1 respectively . The estimated total annual effective dose outdoor for the sites range from 27.3-79.9 ?Sv y?1.Conclusions: This showed that radiation exposure level for the public is lower than the recommended value of 1 mSv y?1.Hence, the extensive usage of radioactive materials within and around CERT does not appear to have any impact on the radiation burden of the environment.

  10. Survey of Gamma Dose and Radon Exhalation Rate from Soil Surface of High Background Natural Radiation Areas in Ramsar, Iran

    Directory of Open Access Journals (Sweden)

    Rouhollah Dehghani

    2013-09-01

    Full Text Available Background: Radon is a radioactive gas and the second leading cause of death due to lung cancer after smoking. Ramsar is known for having the highest levels of natural background radiation on earth. Materials and Methods: In this research study, 50 stations of high radioactivity areas of Ramsar were selected in warm season of the year. Then gamma dose and radon exhalation rate were measured.Results: Results showed that gamma dose and radon exhalation rate were in the range of 51-7100 nSv/hr and 9-15370 mBq/m2s, respectively.Conclusion: Compare to the worldwide average 16 mBq/m2s, estimated average annual effective of Radon exhalation rate in the study area is too high.

  11. Background radiation dose-rates to non-human biota in a high mountain habitat in Norway

    DEFF Research Database (Denmark)

    Brown, J.E.; Gelsvik, R.; Kålås, J.A.;

    2009-01-01

    with activity concentrations reported for reindeer muscle sampled at proximate locations, falling at a level of some 10s of Bq kg-1 by fresh weight. Statistical analyses of the data showed that bank vole and shrew 210Po data constitute different populations with different mean ranks. Unweighted dose-rates......Determination of background radiation dose-rates is important in the process of assessing risks to the environment from exposure to human activities both in terms of deriving the incremental dose-rate and as a point of reference for evaluating the significance of the exposure level. A consideration...... attributable to the presence of internally distributed 210Po were calculated to be 0.07 μGy h-1 for Bank vole....

  12. Assessment of indoor radiation dose received by the residents of natural high background radiation areas of coastal villages of Kanyakumari district, Tamil Nadu, India

    International Nuclear Information System (INIS)

    Radiation exposure and effective dose received through two routes of exposure, viz. external and internal, via inhalation, by residents of 10 villages belonging to Natural High Background Radiation Areas (NHBRA) of coastal regions of Kanyakumari District and Tamil Nadu in India were studied. While the indoor gamma radiation levels were monitored using Thermo Luminescent Dosimeters (TLDs), the indoor radon and thoron gas concentrations were measured using twin chamber dosimeters employing Solid State Nuclear Track Detectors (SSNTDs, LR-115-II). The average total annual effective dose was estimated and found to be varying from 2.59 to 8.76 mSv. -- Highlights: → The effective dose received by the villages of Natural High Background Area (NHBRA) such as Enayam, Midalam and Mel Midalam is high when compared with other study areas. → The high dose indicates higher concentration of radioactive nuclides like Thorium and Uranium in the soil. → As radiation is harmful to human life, the external and internal doses can be reduced by removing the monazite content present in the soil by mineral separation. → Contribution from vegetables, fruits, fish and other non vegetarian items are also being examined. → These results along with other socio-economic factors can throw considerable light on the epidemiological impacts due to low levels of chronic exposure.

  13. Assessment of indoor radiation dose received by the residents of natural high background radiation areas of coastal villages of Kanyakumari district, Tamil Nadu, India

    Energy Technology Data Exchange (ETDEWEB)

    Deva Jayanthi, D., E-mail: d.devajayanthi@gmail.co [Department of Physics, Women' s Christian College, Nagercoil 629001 (India); Maniyan, C.G. [Environmental Assessment Division, BARC, Mumbai 400085 (India); Perumal, S. [Department of Physics and Research Centre, S.T.Hindu College, Nagercoil 629002 (India)

    2011-07-15

    Radiation exposure and effective dose received through two routes of exposure, viz. external and internal, via inhalation, by residents of 10 villages belonging to Natural High Background Radiation Areas (NHBRA) of coastal regions of Kanyakumari District and Tamil Nadu in India were studied. While the indoor gamma radiation levels were monitored using Thermo Luminescent Dosimeters (TLDs), the indoor radon and thoron gas concentrations were measured using twin chamber dosimeters employing Solid State Nuclear Track Detectors (SSNTDs, LR-115-II). The average total annual effective dose was estimated and found to be varying from 2.59 to 8.76 mSv. -- Highlights: {yields} The effective dose received by the villages of Natural High Background Area (NHBRA) such as Enayam, Midalam and Mel Midalam is high when compared with other study areas. {yields} The high dose indicates higher concentration of radioactive nuclides like Thorium and Uranium in the soil. {yields} As radiation is harmful to human life, the external and internal doses can be reduced by removing the monazite content present in the soil by mineral separation. {yields} Contribution from vegetables, fruits, fish and other non vegetarian items are also being examined. {yields} These results along with other socio-economic factors can throw considerable light on the epidemiological impacts due to low levels of chronic exposure.

  14. Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body

    OpenAIRE

    Pattison, John E; Hugtenburg, Richard P.; Green, Stuart

    2009-01-01

    Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy ...

  15. Local microwave background radiation

    OpenAIRE

    Soares, Domingos

    2006-01-01

    An inquiry on a possible local origin for the Microwave Background Radiation is made. Thermal MBR photons are contained in a system called {\\it magnetic bottle} which is due to Earth magnetic field and solar wind particles, mostly electrons. Observational tests are anticipated.

  16. Dose-effect relationship in production of dicentrics and rings in blood lymphocytes of individuals living in high background radiation area

    International Nuclear Information System (INIS)

    Objective: To explore the dose-effect relationship in the production of chromosome aberrations by high background radiation by using statistically appropriate individual measurements. Methods: Chromosome analysis was performed in separated blood lymphocytes of 39 family members of different ages from either high background radiation area (HBRA) or control area (CA). Individual cumulative doses ranged from 23.9-261.3 and 5.2-29.8 mGy for HBRA and CA, respectively. A total of about 100,000 cells were scored and dicentric and ring chromosome (dic + Rc) aberrations recorded. Results: In the case of HBRA, individual chromosome aberration frequencies increased with age within each family. The increasing trend was in general not significantly different among families. The increase in individual aberration was closely correlated with age and cumulative dose. Age-and dose-effect relationship fit well the linear equation: Y = 0.0448X + 0.4913 (R2 = 0.7814) for age and Y 0.0156X + 0.5715 (R2 = 0.7061) for cumulative dose, respectively. In the case of CA, there was no significant difference in aberration yields among individuals of different ages, and the group mean aberration frequency was 1.24 +- 0.69 x 10-3. Conclusions: Dic and Rc can continuously accumulate over a lifetime chronic low dose exposures, and can serve as a reliable biological indicator. However, the ultimate sensitivity is about 50 mGy

  17. Registration of radiation doses

    International Nuclear Information System (INIS)

    In Finland the Radiation and Nuclear Safety Authority (STUK) is maintaining the register (called Dose Register) of the radiation exposure of occupationally exposed workers in order to ensure compliance with the principles of optimisation and individual protection. The guide contains a description of the Dose Register and specifies the responsibilities of the party running a radiation practice to report the relevant information to the Dose Register

  18. Dose-effect relationship of dicentric and ring chromosomes in lymphocytes of individuals living in the high background radiation areas in China

    International Nuclear Information System (INIS)

    Chromosomes of 39 healthy family members (3 generations from 13 families) living both in the high-level background radiation areas (HBRA) and the control areas (CA) were studied. Cumulative dose from birth to the time of blood sampling was estimated by calculating measured exposure rate in each individual. The cumulative doses ranged 30.9-358.9 and 6.0-59.2 mGy for HBRA and CA, respectively. Peripheral lymphocyte chromosome preparations were made according to our improved method. Dicentric and ring chromosomes (Dic+Rc) were scored in average 2,527 cells per individual in HBRA and 2,694 cells in CA under a microscope equipped with an automated stage. A positive correlation between Dic+Rc and age was found in HBRA, while no such dose relationship was clear in CA. The frequency of Dic+Rc linearly increases over lifetime due to chronic low dose exposure and it is likely that the activation of repair enzymes is not triggered in the present HBRA. Threshold dose (rate) of the induction of chromosome aberrations, if any, is below the present dose (rate) level. (author)

  19. Ultraviolet Background Radiation

    Science.gov (United States)

    Henry, R. C.; Murthy, J.

    1993-12-01

    The UVX experiment was carried on the Space Shuttle Columbia between 1986 January 12 and 19 (STS-61C). Several ultraviolet spectrometers were used to obtain measurements of the diffuse ultraviolet background at 8 locations in the sky. We have reanalysed the UVX measurements of the surface brightness of the diffuse ultraviolet background above b = 40 using the dust-scattering model of Onaka & Kodaira (1991), which explicitly takes into account the variation of the source function with galactic longitude. The range of allowed values of interstellar grain albedoJa, and scattering asymmetry parameter g, is considerably expanded over those of a previous analysis. The new chi square probability contours come close to, but do not include, the values of a and g found for the interstellar grains by Witt et al. (1992) using the Ultraviolet Imaging Telescope (UIT) on the Astro mission. If we hypothesize in additon to the dust-scattered light an extragalactic component, of 300 1 100 photons cm-2 s-1 sr-1 A-1, attenuated by a cosecant b law, the new reduction of the UVX data gives complete consistency with the Witt et al. determination of the optical parameters of the grains in the ultraviolet. This work was supported by United States Air Force Contract F19628-93-K-0004, and by National Aeronautics and Space Administration grant NASA NAG5-619. We are grateful for the encouragement of Dr. Stephan Price, and we thank Dr. L. Danly for information. Onaka, T., & Kodaira, K. 1991, ApJ, 379, 532 Witt, A. N., Petersohn, J. K., Bohlin, R. C., O'Connell, R. W., Roberts, M. S., Smith, A. M., & Stecher, T. P. 1992, ApJ, 395, L5

  20. Terrestrial gamma dose rate, radioactivity and radiological hazards in the rocks of an elevated radiation background in Juban District, Ad Dali' Governorate, Yemen.

    Science.gov (United States)

    Abdurabu, Wedad Ali; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Heryansyah, Arien; Alnhary, Anees; Fadhl, Shadi

    2016-03-01

    This study aims to evaluate natural radiation and radioactivity in the rock and to assess the corresponding health risk in a region of elevated background radiation in Juban District, Ad Dali' Governorate, Yemen. The mean external gamma dose rate was 374 nGy h(-1) which is approximately six times the world average. The measured results were used to compute annual effective dose equivalent, collective effective dose and excess lifetime cancer risk, which are 2.298 mSv, 61.95 man Sv y(-1) and 8.043  ×  10(-3), respectively. Rocks samples from different geological formations were analyzed for quantitative determination of (226)Ra, (232)Th and (40)K. The specific activity of the rocks samples ranges from 7  ±  1 Bq Kg(-1) to 12 513  ±  329 Bq Kg(-1) for (232)Th, from 6  ±  1 Bq kg(-1) to 3089  ±  74 Bq kg(-1) for (226)Ra and 702  ±  69 Bq kg(-1) to 2954  ±  285 Bq kg(-1) for (40)K. (232)Th is the main contributor to gamma dose rate from the rock samples. Indicators of radiological health impact, radium equivalent activity and external hazard index are 3738 Bq kg(-1) and 10.10, respectively. The mean external hazard index was ten times unity in the studied locations in Juban District, which is higher than the recommended value. PMID:26909670

  1. Radiation dose in vertebroplasty

    Energy Technology Data Exchange (ETDEWEB)

    Mehdizade, A.; Lovblad, K.O.; Wilhelm, K.E.; Somon, T.; Wetzel, S.G.; Kelekis, A.D.; Yilmaz, H.; Abdo, G.; Martin, J.B.; Viera, J.M.; Ruefenacht, D.A. [Neuroradiology DRRI, Geneva University Hospital, Rue Micheli-du-Crest 24, 1211, Geneva 14 (Switzerland)

    2004-03-01

    We wished to measure the absorbed radiation dose during fluoroscopically controlled vertebroplasty and to assess the possibility of deterministic radiation effects to the operator. The dose was measured in 11 consecutive procedures using thermoluminescent ring dosimeters on the hand of the operator and electronic dosimeters inside and outside of the operator's lead apron. We found doses of 0.022-3.256 mGy outside and 0.01-0.47 mGy inside the lead apron. Doses on the hand were higher, 0.5-8.5 mGy. This preliminary study indicates greater exposure to the operator's hands than expected from traditional apron measurements. (orig.)

  2. Natural background radiation in Canada

    International Nuclear Information System (INIS)

    Published airborne gamma ray survey data from 33 areas of Canada were used to compile information on the average ground level exposure from natural radiation. The exposures at ground level were calculated from the surface concentrations of potassium, uranium and thorium. The highest levels of radioactivity were found in northern Canada and were generally related to granitic rocks; the lowest levels with the Athabasca sandstone. Summer outdoor exposure rates have a population-weighted average of 3.7 +- 2.3 μR.h-1, of which 48 percent orginated from potassium, 43 percent from the thorium series and 9 percent from the uranium series. This low level of radioactivity, compared to worldwide data, has resulted from erosion of a geologically old continental crust in which radioactivity decreases with depth. When seasonal variations of soil moisture and snow cover are considered, the annual population-weighted average outdoor exposure rate decreases to 2.8 +- 1.7 μR.h-1 corresponding to an annual outdoor dose-equivalent of 150 +- 90 μSV. Factors increasing the annual outdoor dose-equivalent are cosmic radiation (320 +- 30 μSV) and the internal radioactivity of the body (190 μSV). Using the ratio between indoor and outdoor values for worldwide published data, the average annual Canadian whole-body dose-equivalent from all sources of natural radiation is estimated to be 690 +-130 μSV

  3. Doses from radiation exposure

    CERN Document Server

    Menzel, H G

    2012-01-01

    Practical implementation of the International Commission on Radiological Protection's (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP's 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effecti...

  4. Remote Background Radiation Monitoring Using Zigbee Technology

    Directory of Open Access Journals (Sweden)

    Hamisu A. Adamu

    2014-03-01

    Full Text Available In this paper, a solution of remote background radiation monitoring, based on the concept of Wireless Sensor Network (WSN, is presented. Radiation dose rate measured by the sensor node is sent to the monitoring station through ZigBee wireless network operated on 2.4 GHz unlicensed Industrial Scientific Medical (ISM band. The system is calibrated for use for ionizing radiation dose rate range of between naturally occurring background radiation and 1.02 mSv/h. Power consumption of the sensor node is kept low by operating the node ZigBee radio with low duty cycle: i.e by keeping the radio awake only during data transmission/reception. Two ATmega8 microcontrollers, one each for sensor node and the monitoring station, are programmed to perform interfacing, data processing, and control functions. The system range of coverage is 124m for outdoor (line of site deployment and 56.8m for indoor application where 5 brick walls separated the sensor node and the monitoring station. Range of coverage of the system is extendable via the use of ZigBee router(s.

  5. Prenatal radiation doses from radiopharmaceuticals

    International Nuclear Information System (INIS)

    The radiopharmaceutical administration with diagnostic or therapeutic purpose during pregnancy implies a prenatal radiation dose. The dose assessment and the evaluation of the radiological risks become relevant due to the great radiosensitivity of the fetal tissues in development. This paper is a revision of the available data for estimating fetal doses in the cases of the more frequently used radiopharmaceuticals in nuclear medicine, taking into account recent investigation in placental crossover. The more frequent diagnostic and therapeutic procedures were analyzed according to the radiation doses implied. (author)

  6. Background gamma terrestrial dose rate in Nigerian functional coal mines

    International Nuclear Information System (INIS)

    Measurements of the background terrestrial gamma radiation dose rates at different indoor and outdoor locations on the surfaces of Okpara underground and Okaba open cast mines in Nigeria were made. Two duly calibrated low-level gamma survey metres were held 1 m above the ground surface for these measurements. Measurements were also made at various locations inside the mine tunnel at the Okpara mine. Results indicate that the indoor background gamma radiation is comparable for both mining environments. The mean outdoor gamma dose rate determined for the Okaba mining environment is 10.4 nGy h-1 as against 11.7 nGy h-1 for Okpara. The ranges are 8.5-16.5 nGy h-1 for the Okpara measurements and 7.5-14.0 nGy h-1 for Okaba. Thus, the outdoor gamma dose rates appear to be generally lower at the Okaba open cast mine than at Okpara. The indoor dose rate values range from 11.0 to 17.0 nGy h-1 in both environments. These indoor measurements have nearly the same mean values 14.4 and 14.5 nGy h-1 for Okpara and Okaba environments, respectively. The indoor to outdoor dose rate ratio is 1.2 for Okpara and 1.4 for Okaba. These values are in consonance with the corresponding ratio given in literature. Dose rate measurements inside the mine tunnel at the Okpara mine are higher than the surface indoor measurements ranging from 13.5 to 20.5 nGy h-1 with a mean of 16.5 nGy h-1. The higher dose rate values measured in the mine tunnel are attributable to the concentration of radon in the 'closed' environment of the mine tunnel. (authors)

  7. Radiation dose estimates for radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Stabin, M.G.; Stubbs, J.B.; Toohey, R.E. [Oak Ridge Inst. of Science and Education, TN (United States). Radiation Internal Dose Information Center

    1996-04-01

    Tables of radiation dose estimates based on the Cristy-Eckerman adult male phantom are provided for a number of radiopharmaceuticals commonly used in nuclear medicine. Radiation dose estimates are listed for all major source organs, and several other organs of interest. The dose estimates were calculated using the MIRD Technique as implemented in the MIRDOSE3 computer code, developed by the Oak Ridge Institute for Science and Education, Radiation Internal Dose Information Center. In this code, residence times for source organs are used with decay data from the MIRD Radionuclide Data and Decay Schemes to produce estimates of radiation dose to organs of standardized phantoms representing individuals of different ages. The adult male phantom of the Cristy-Eckerman phantom series is different from the MIRD 5, or Reference Man phantom in several aspects, the most important of which is the difference in the masses and absorbed fractions for the active (red) marrow. The absorbed fractions for flow energy photons striking the marrow are also different. Other minor differences exist, but are not likely to significantly affect dose estimates calculated with the two phantoms. Assumptions which support each of the dose estimates appears at the bottom of the table of estimates for a given radiopharmaceutical. In most cases, the model kinetics or organ residence times are explicitly given. The results presented here can easily be extended to include other radiopharmaceuticals or phantoms.

  8. Evaluation of radiation doses delivered in different chest CT protocols

    OpenAIRE

    Gorycki, Tomasz; Lasek, Iwona; Kamiński, Kamil; Studniarek, Michał

    2014-01-01

    Summary Background There are differences in the reference diagnostic levels for the computed tomography (CT) of the chest as cited in different literature sources. The doses are expressed either in weighted CT dose index (CTDIVOL) used to express the dose per slice, dose-length product (DLP), and effective dose (E). The purpose of this study was to assess the radiation dose used in Low Dose Computer Tomography (LDCT) of the chest in comparison with routine chest CT examinations as well as to ...

  9. Radiation Leukemogenesis at Low Dose Rates

    Energy Technology Data Exchange (ETDEWEB)

    Weil, Michael; Ullrich, Robert

    2013-09-25

    The major goals of this program were to study the efficacy of low dose rate radiation exposures for the induction of acute myeloid leukemia (AML) and to characterize the leukemias that are caused by radiation exposures at low dose rate. An irradiator facility was designed and constructed that allows large numbers of mice to be irradiated at low dose rates for protracted periods (up to their life span). To the best of our knowledge this facility is unique in the US and it was subsequently used to study radioprotectors being developed for radiological defense (PLoS One. 7(3), e33044, 2012) and is currently being used to study the role of genetic background in susceptibility to radiation-induced lung cancer. One result of the irradiation was expected; low dose rate exposures are ineffective in inducing AML. However, another result was completely unexpected; the irradiated mice had a very high incidence of hepatocellular carcinoma (HCC), approximately 50%. It was unexpected because acute exposures are ineffective in increasing HCC incidence above background. This is a potential important finding for setting exposure limits because it supports the concept of an 'inverse dose rate effect' for some tumor types. That is, for the development of some tumor types low dose rate exposures carry greater risks than acute exposures.

  10. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  11. Radiation background of Black Sea coastal environment

    International Nuclear Information System (INIS)

    The main objective of the project is to establish the level of radiation background and its sources in the Black Sea coastal environment. Marine samples will be collected in the Black Sea Coast area. The content of different radionuclides will be analyzed and the results will be used in a GIS application. The gamma emitting radionuclides will be measured in ultralow radiation background in the Romanian underground laboratory in salt mine in Slanic-Prahova. The main expected results is an up to date quantification of the radiation sources of the background of the Black Sea coastal environment. (authors)

  12. EXOMARS IRAS (DOSE) radiation measurements.

    Science.gov (United States)

    Federico, C.; Di Lellis, A. M.; Fonte, S.; Pauselli, C.; Reitz, G.; Beaujean, R.

    The characterization and the study of the radiations on their interaction with organic matter is of great interest in view of the human exploration on Mars. The Ionizing RAdiation Sensor (IRAS) selected in the frame of the ExoMars/Pasteur ESA mission is a lightweight particle spectrometer combining various techniques of radiation detection in space. It characterizes the first time the radiation environment on the Mars surface, and provide dose and dose equivalent rates as precursor information absolutely necessary to develop ways to mitigate the radiation risks for future human exploration on Mars. The Martian radiation levels are much higher than those found on Earth and they are relatively low for space. Measurements on the surface will show if they are similar or not to those seen in orbit (modified by the presence of ``albedo'' neutrons produced in the regolith and by the thin Martian atmosphere). IRAS consists of a telescope based on segmented silicon detectors of about 40\\userk\\milli\\metre\\user;k diameter and 300\\user;k\\micro\\metre\\user;k thickness, a segmented organic scintillator, and of a thermoluminescence dosimeter. The telescope will continuously monitor temporal variation of the particle count rate, the dose rate, particle and LET (Linear Energy Transfer) spectra. Tissue equivalent BC430 scintillator material will be used to measure the neutron dose. Neutrons are selected by a criteria requiring no signal in the anti-coincidence. Last, the passive thermoluminescence dosimeter, based on LiF:Mg detectors, regardless the on board operation timing, will measure the total dose accumulated during the exposure period and due to beta and gamma radiation, with a responsivity very close to that of a human tissue.

  13. Occupational radiation doses to personnel

    International Nuclear Information System (INIS)

    Results are presented of 2-year measurements of personnel doses performed according to the program of Personel Dosimetry Centre of Leningrad Scientific Research Institute of Radiation Hygiene. Investigations were carried out in 7 regions of the USSR. Thermoluminescent ''Harshow 2000 D'' dosemeter and lithium fluoride detector were used. Mean dose for all occupational groups (defectoscopists, personnel of radioactive waste disposal, medical radiologists) is found to be not exceeding 10% of maximum permissible dose. It is concluded that working conditions of personnel tested meet the requirements of RPG-76 and sanitary rules BSR-72/80

  14. Prenatal radiation exposure. Dose calculation

    International Nuclear Information System (INIS)

    The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero X-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties.

  15. Health effect of low dose/low dose rate radiation

    International Nuclear Information System (INIS)

    The clarified and non-clarified scientific knowledge is discussed to consider the cause of confusion of explanation of the title subject. The low dose is defined roughly lower than 200 mGy and low dose rate, 0.05 mGy/min. The health effect is evaluated from 2 aspects of clinical symptom/radiation hazard protection. In the clinical aspect, the effect is classified in physical (early and late) and genetic ones, and is classified in stochastic (no threshold value, TV) and deterministic (with TV) ones from the radioprotection aspect. Although the absence of TV in the carcinogenic and genetic effects has not been proved, ICRP employs the stochastic standpoint from the safety aspect for radioprotection. The lowest human TV known now is 100 mGy, meaning that human deterministic effect would not be generated below this dose. Genetic deterministic effect can be observable only in animal experiments. These facts suggest that the practical risk of exposure to <100 mGy in human is the carcinogenesis. The relationship between carcinogenic risk in A-bomb survivors and their exposed dose are found fitted to the linear no TV model, but the epidemiologic data, because of restriction of subject number analyzed, do not always mean that the model is applicable even below the dose <100 mGy. This would be one of confusing causes in explanation: no carcinogenic risk at <100 mGy or risk linear to dose even at <100 mGy, neither of which is scientifically conclusive at present. Also mentioned is the scarce risk of cancer in residents living in the high background radiation regions in the world in comparison with that in the A-bomb survivors exposed to the chronic or acute low dose/dose rate. Molecular events are explained for the low-dose radiation-induced DNA damage and its repair, gene mutation and chromosome aberration, hypothesis of carcinogenesis by mutation, and non-targeting effect of radiation (bystander effect and gene instability). Further researches to elucidate the low dose

  16. Gamma radiation background measurements from Spacelab 2

    Science.gov (United States)

    Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

    1989-01-01

    A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

  17. Evaluation of background ionising radiation levels within Gwagwalada town, Abuja

    International Nuclear Information System (INIS)

    The background ionising radiation levels within Gwagwalada Town, Abuja has been carried out using Atomtex 1117M Radiation Monitor. Readings were taken in twelve different locations. Twenty different readings were taken at each location and the mean equivalent dose rate was used to calculate the annual equivalent dose rate. A total of 240 measurements were taken across the 12 locations in the study Area. It was observed that the average dose equivalent varied from 0.105±0.008 μSv/h to 0.114±0.015μSv/h with a mean of 0.109±0.013 μSv/h. The mean value from Ungwan Bassa shows the highest equivalent dose rate while the equivalent dose rate from Phase 3 was the lowest. Ungwan Dodo, Ungwan Gwari recorded the second and third highest in-situ gamma radiation of 0.113±0.013 μSv/h and 0.112±0.012 μSv/h respectively. The result shows that the entire equivalent dose rates of all the locations were below the value of the Standard Background Radiation of 0.133 μSv/h. The study also revealed that the average annual equivalent dose rate is 0.192±0.005 mSv/y which is lower than the value of 1.0 mSv/yr averaged over five consecutive years according to the dose limit recommended by the International Commission on Radiological Protection (ICRP).

  18. Biology responses to low dose radiation

    International Nuclear Information System (INIS)

    Biology responses to low dose radiation is the most important problem of medical radiation and radiation protection. The especial mechanism of low dose or low dose rate induced cell responses, has been found independent with linear no-threshold model. This article emphasize to introduce low dose or low dose rate induced biology responses of adaptive response, by-effect, super-sensitivity and genomic instability. (authors)

  19. Controllable forms of natural background radiation

    International Nuclear Information System (INIS)

    RENA is a research programm into the controllable forms of natural background radiation, which cover the activities originating from the naturally occurring radionuclides enhanced by human intervention. In the RENA-program emphasis lays upon the policy aspects of environmental-hygienic, economical and governmental character. (H.W.). 15 refs.; 2 tabs

  20. An investigation of gamma background radiation in Hamadan province, Iran

    International Nuclear Information System (INIS)

    The general population, everywhere in the world is exposed to a small dose of ionising radiation from natural sources. Stochastic effects such as cancer and genetic disorders are caused when living creatures are exposed to low doses. In Iran, it is measured in some cities, especially in high-background areas such as Ramsar, but so far there is no measurement in the Hamadan province. Hamadan is located in the west of Iran. Measurements were performed using a RDS-110 survey meter, CaSO4:Dy thermoluminescence dosimetries (TLDs) and a Harshaw 4000 TLD reader. To estimate the dose rate outdoors, four stations along the main directions (north, south, west and east) and one in the town centre were selected. Mean annual X and gamma equivalent dose in Hamadan province are 1.12±0.22 and 1.66±0.07 mSv, which related to RDS-110 survey meter and TLDs measurements, respectively. The TLDs and RDS-110 results are representative of the external photon radiation doses for the selected monitoring locations and for those locations for the hours during which the measurements were taken, respectively. Maximum and minimum of external photon radiation doses are related to Hamadan and Kaboudar-Ahang towns, respectively. According to the results of the study, it seems that the annual X and gamma equivalent dose in Hamadan province exceeded the global mean external exposure amounts by the UNSCEAR, and further studies are needed to measure internal exposures to determine the total environmental radiation level in Hamadan province. (authors)

  1. Cosmic microwave background radiation: anisotropies and polarization

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Sergio Vitorino de Borba; Guaitolini Junior, J.T. [Universidade Federal do Espirito Santo (UFES), ES (Brazil). Dept. de Fisica

    2011-07-01

    Full text: The development of cosmological models which describe correctly the universe we live in is becoming more reliable, as the improvement of the measure tools provides us with more accurate information. The Cosmic Microwave Background Radiation (CMB) was discovered accidentally by Arno Penzias and Robert Wilson in early 60s, becoming a strong evidence in favor of the Big Bang model. This radiation, typical of a blackbody with maximum intensity in the microwave band, was already predicted by Gamov, Alpher and Herman and it's originated from the uncoupling between radiation and matter in recombination, at z = 1088. Nowadays, since no other observable in Cosmology provides us with information of such a distant past, studying CMB is of great importance for the process of the comprehension of the universe. The detection of small anisotropies at the temperatures distribution, which remain even after considering the universe recent phenomena and effects of referential movements, evidenced that the primordial universe was closer to the thermodynamic equilibrium and that the appearance of small inhomogeneities were the beginning of the formation of the structures we see today. These small anisotropies are important because from them it is possible to observe polarization at CMB. In a universe so perfectly homogeneous and isotropic, polarization would never exist. In this work, we calculate the behavior of light propagation in a disturbed universe, obtaining anisotropies from the potential variation at the radiation way and from the peculiar velocity of matter which spread radiation in our direction. At this point, the next purpose is to theoretically calculate these anisotropies in an alternative cosmological example, such as in Brans-Dicke theory or a model of an universe filled with a viscous fluid. Besides, with the Stokes Parameters describing the radiation field, we study the CMB polarization, in particular analyzing the polarization tensor in a 2-sphere as

  2. Background internal dose rates of earthworm and arthropod species in the forests of Aomori, Japan

    International Nuclear Information System (INIS)

    In this study, we measured the concentrations of several natural radionuclides in samples of one earthworm species and 11 arthropod species collected from four coniferous forests in Rokkasho, Aomori Prefecture, Japan, and we assessed the background internal radiation dose rate for each species. Dose rates were calculated by using the radionuclide concentrations in the samples and dose conversion coefficients obtained from the literature. The mean internal dose rate in the earthworm species was 0.28 μGy h-1, and the mean internal dose rates in the arthropod species ranged between 0.036 and 0.69 μGy h-1. (author)

  3. Doses from Medical Radiation Sources

    Science.gov (United States)

    ... Radiation Protection and Measurements; NCRP Report 124; 1996. United Nations Scientific Committee on the Effects of Atomic Radiation. ... ionizing radiation, Vol. 1: Sources. New York, NY: United Nations Publishing; 2000. Russell JR, Stabin MG, Sparks RB, ...

  4. Significance of epidemiological and cytogenetic studies on high background radiation area residents

    International Nuclear Information System (INIS)

    Some area in the world are known as background levels of radiation are 3-5 times higher than the world average. The studies in high background area (HBRA) residents provide important direct information on the biological and health effects of chronic low dose rate radiation. (author)

  5. Potential radiation doses from 1994 Hanford Operations

    Energy Technology Data Exchange (ETDEWEB)

    Soldat, J.K.; Antonio, E.J.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the potential radiation doses to the public from releases originating at the Hanford Site. Members of the public are potentially exposed to low-levels of radiation from these effluents through a variety of pathways. The potential radiation doses to the public were calculated for the hypothetical MEI and for the general public residing within 80 km (50 mi) of the Hanford Site.

  6. Occupational radiation doses during interventional procedures

    Science.gov (United States)

    Nuraeni, N.; Hiswara, E.; Kartikasari, D.; Waris, A.; Haryanto, F.

    2016-03-01

    Digital subtraction angiography (DSA) is a type of fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. The use of DSA procedures has been increased quite significantly in the Radiology departments in various cities in Indonesia. Various reports showed that both patients and medical staff received a noticeable radiation dose during the course of this procedure. A study had been carried out to measure these doses among interventionalist, nurse and radiographer. The results show that the interventionalist and the nurse, who stood quite close to the X-ray beams compared with the radiographer, received radiation higher than the others. The results also showed that the radiation dose received by medical staff were var depending upon the duration and their position against the X-ray beams. Compared tothe dose limits, however, the radiation dose received by all these three medical staff were still lower than the limits.

  7. Dose Assurance in Radiation Processing Plants

    DEFF Research Database (Denmark)

    Miller, Arne; Chadwick, K.H.; Nam, J.W.

    1983-01-01

    Radiation processing relies to a large extent on dosimetry as control of proper operation. This applies in particular to radiation sterilization of medical products and food treatment, but also during development of any other process. The assurance that proper dosimetry is performed at the...... radiation processing plant can be obtained through the mediation of an international organization, and the IAEA is now implementing a dose assurance service for industrial radiation processing....

  8. Dose assurance in radiation processing plants

    International Nuclear Information System (INIS)

    Radiation processing relies to a large extent on dosimetry as control of proper operation. This applies in particular to radiation sterilization of medical products and food treatment, but also during development of any other process. The assurance that proper dosimetry is performed at the radiation processing plant can be obtained through the mediation of an international organization, and the IAEA is now implementing a dose assurance service for industrial radiation processing. (author)

  9. Dose assurance in radiation processing plants

    Science.gov (United States)

    Miller, A.; Chadwick, K. H.; Nam, J. W.

    Radiation processing relies to a large extent on dosimetry as control of proper operation. This applies in particular to radiation sterilization of medical products and food treatment, but also during development of any other process. The assurance that proper dosimetry is performed at the radiation processing plant can be obtained through the mediation of an international organization, and the IAEA is now implementing a dose assurance service for industrial radiation processing.

  10. Characterization of the radiation background at the Spallation Neutron Source

    Science.gov (United States)

    DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.; Hall-Wilton, Richard J.; Bentley, Phillip M.

    2016-09-01

    We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden.

  11. Radiation Doses from Computed tomography in Iraq

    International Nuclear Information System (INIS)

    Radiation doses to Patient during CT scanner and the radiological risk are significant. Patient dose survey has been conducted to investigate the Iraq patient radiation doses received in CT scanners in order to established reference dose levels. These doses are Entrance Surface Dose (ESD),computed tomography dose index(CTDI)), and dose length product (DLP). Two CT scanner were investigated in this study were, Siemens Somatom Plus 4, located in at medical city of Baghdad, and Philips, Optimus located in privet hospital at Baghdad. ESD were measured by TLD and Dosimax ionization chamber for head, chest, and abdomen for both sex and different weights. The TLD results were higher than that measured with Dosimax due to scattered radiation .The scattering factor which is the ratio between dose measured by TLD and that measured by ionization chamber range between (1.14-1.34) compare to international measurement which is range between (1.1-1.5).The (ESD) measured by the two methods were agree well after the subtraction of scattering dose, and have compered with original research. Dose profile were measured using array of TLD chips shows that its full width at half maximum is(7.99 mm) approximately equal the slice thickness(8 mm). Our results compare with reference level at U.K, European Guidelines and

  12. Calculating the background radiation in the vicinity of the beam catchers of the ELBE radiation source

    International Nuclear Information System (INIS)

    The ELBE radiation sources comprises beam catchers in the experimenting sites which absorb the primary electron beam as well as the generated secondary radiation. The beam catcher consists of an ultrapure graphite absorber enclosed in a water-cooled stainless steel shell. Background radiation is shielded by iron, lead and heavy concrete. The beam parameters and the position of the beam catchers differ between experimenting sites. In order to determine the dose dependence of photon and neutron fluence and the dose equivalent at the cooling shell of the beam catcher, simulations were carried out using the FLUKA code. Radiation energies of 20 MeV and 50 MeV and electron fluxes of 1 mA were considered. The spatial and energetic distributions of the dose rate equivalent provide a basis for dimensioning of the radiation shields. The calculated distributions of the energy dose rate in the beam catcher serve as a basis for assessing thermal loads on materials and for designing the cooling system. (orig.)

  13. Effective dose: a radiation protection quantity

    CERN Document Server

    Menzel, H G

    2012-01-01

    Modern radiation protection is based on the principles of justification, limitation, and optimisation. Assessment of radiation risks for individuals or groups of individuals is, however, not a primary objective of radiological protection. The implementation of the principles of limitation and optimisation requires an appropriate quantification of radiation exposure. The International Commission on Radiological Protection (ICRP) has introduced effective dose as the principal radiological protection quantity to be used for setting and controlling dose limits for stochastic effects in the regulatory context, and for the practical implementation of the optimisation principle. Effective dose is the tissue weighted sum of radiation weighted organ and tissue doses of a reference person from exposure to external irradiations and internal emitters. The specific normalised values of tissue weighting factors are defined by ICRP for individual tissues, and used as an approximate age- and sex-averaged representation of th...

  14. Thermal radiation of various gravitational backgrounds

    OpenAIRE

    Akhmedov, Emil T.; Akhmedova, Valeria; Pilling, Terry; Singleton, Douglas

    2006-01-01

    We present a simple and general procedure for calculating the thermal radiation coming from any stationary metric. The physical picture is that the radiation arises as the quasi--classical tunneling of particles through a gravitational barrier. We show that our procedure can reproduce the results of Hawking and Unruh radiation. We also show that under certain kinds of coordinate transformations the temperature of the thermal radiation will change in the case of the Schwarzschild black holes. ...

  15. Human exposure to high natural background radiation: what can it teach us about radiation risks?

    Energy Technology Data Exchange (ETDEWEB)

    Hendry, Jolyon H; Sohrabi, Mehdi; Burkart, Werner [Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna (Austria); Simon, Steven L [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD (United States); Wojcik, Andrzej [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Cardis, Elisabeth [Centre for Research in Environmental Epidemiology (CREAL), Municipal Institute of Medical Research (IMIM-Hospital del Mar) and CIBER Epidemiologia y Salud Publica - CIBERESP, Barcelona (Spain); Laurier, Dominique; Tirmarche, Margot [Radiobiology and Epidemiology Department, Radiological and Human Health Division, Institute for Radiological Protection and Nuclear Safety, Fontenay-aux-Roses (France); Hayata, Isamu [National Institute of Radiological Sciences, Chiba (Japan)], E-mail: jhendry2002uk@yahoo.com

    2009-06-01

    Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of {sup 222}Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case-control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case-control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors.

  16. Development of radiation dose assessment system for radiation accident (RADARAC)

    International Nuclear Information System (INIS)

    The possibility of radiation accident is very rare, but cannot be regarded as zero. Medical treatments are quite essential for a heavily exposed person in an occurrence of a radiation accident. Radiation dose distribution in a human body is useful information to carry out effectively the medical treatments. A radiation transport calculation utilizing the Monte Carlo method has an advantageous in the analysis of radiation dose inside of the body, which cannot be measured. An input file, which describes models for the accident condition and quantities of interest, should be prepared to execute the radiation transport calculation. Since the accident situation, however, cannot be prospected, many complicated procedures are needed to make effectively the input file soon after the occurrence of the accident. In addition, the calculated doses are to be given in output files, which usually include much information concerning the radiation transport calculation. Thus, Radiation Dose Assessment system for Radiation Accident (RADARAC) was developed to derive effectively radiation dose by using the MCNPX or MCNP code. RADARAC mainly consists of two parts. One part is RADARAC-INPUT, which involves three programs. A user can interactively set up necessary resources to make input files for the codes, with graphical user interfaces in a personnel computer. The input file includes information concerning the geometric structure of the radiation source and the exposed person, emission of radiations during the accident, physical quantities of interest and so on. The other part is RADARAC-DOSE, which has one program. The results of radiation doses can be effectively indicated with numerical tables, graphs and color figures visibly depicting dose distribution by using this program. These results are obtained from the outputs of the radiation transport calculations. It is confirmed that the system can effectively make input files with a few thousand lines and indicate more than 20

  17. Radiation doses - maps and magnitudes

    International Nuclear Information System (INIS)

    A NRPB leaflet in the 'At-a-Glance' Series presents information on the numerous sources and magnitude of exposure of man to radiation. These include the medical use of radiation, radioactive discharges to the environment, cosmic rays, gamma rays from the ground and buildings, radon gas and food and drink. A Pie chart represents the percentage contribution of each of those sources. Finally, the terms becquerel, microsievert and millisievert are explained. (U.K.)

  18. Mapping the exposure of the Brazilian population to natural background radiation - cosmic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rochedo, Elaine R.R., E-mail: elaine@ird.gov.br [Instituto de Radioprotecao e Dosimetria (lRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Salles, Krause C.S.; Prado, Nadya M.C., E-mail: krausesalles@yahoo.com.br, E-mail: nadya@ime.ib.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The main objective of this work is to statically and graphically describe the exposure of the Brazilian population to natural background radiation. in this stage, doses due to cosmic rays is being assessed based on sea level dose rates, corrected by latitude and altitude, according to the model recommended by UNSCEAR. In this work, the doses were estimated for ali Brazilian municipalities with more than 100.000 inhabitants. The 253 municipalities selected for this study include about 52% of the Brazilian population. Average dose rate was estimated to be about 50 n Sv/h with a variation coefficient of 31%. The estimated doses have shown a strong influence of altitude on dose rates, with a correlation coefficient of 0,998 for ao exponential fit. This result confirms previous studies that show a large effect of the altitude 00 exposure from cosmic radiation. Considering the same occupation and shielding conditions used by UNSCEAR as global averages, average annual dose was estimated to be 0,37 (0,24 - 0,76) mSv/y, very close to UNSCEAR worldwide average of 0,38 (0,3 - 1,0) mSv/y. (author)

  19. A background radiation survey along the transcontinental railway in Australia

    International Nuclear Information System (INIS)

    This article reports a survey, carried out during a period from October 31 to November 3, 1994 in Australia, as well as some basic techniques of train-borne measurements for estimating outdoor gamma-ray dose rates. Surface rock and bedrock data are presented for convenience for geological analysis. Cosmic-ray dose rates estimated from atmospheric pressure data are also presented for researchers who are interested in total background radiation dose rates. It was found that gamma levels can be high in the western area. The dose rate data were based on the shielding correction factor evaluated at platforms in many stations. To confirm the validity of this method, the data from train-borne surveys in central Japan were compared with the present Australian data. There were, to some extent, correlations between them. The present study suggests that the train-borne measurements are useful for surveying wide area in a short time with an error of about 20%. (N.K.)

  20. Dose mapping for documentation of radiation sterilization

    DEFF Research Database (Denmark)

    Miller, A.

    1999-01-01

    The radiation sterilization standards EN 552 and ISO 11137 require that dose mapping in real or simulated product be carried in connection with the process qualification. This paper reviews the recommendations given in the standards and discusses the difficulties and limitations of practical dose...

  1. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice

    Energy Technology Data Exchange (ETDEWEB)

    Ware, J.H.; Rusek, A.; Sanzari, J.; Avery, S.; Sayers, C.; Krigsfeld, G.; Nuth, M.; Wan, X.S.; Kennedy, A.R.

    2010-09-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  2. Dose-effect relationship in radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Oberhausen, E.

    1983-01-01

    As criterion for the evaluation of risk in connection with nuclear accidents the diminishing of life expectance is assumed. This would allow a better weighting of the different detriments. The possible dose-effect relations for the different detriments caused by radiation are discussed. Some models for a realistic evaluation of the different radiation detriments are proposed.

  3. Radiation Doses from some Egyptian industrial products

    International Nuclear Information System (INIS)

    The annual dose equivalent from exposures to radionuclides contained in some industrial ores and their waste products, were estimated using collective data from these industrial materials. This study takes in consideration industrial ores and their waste products. The materials studied were iron and steel products, cement manufacture, phosphate fertilizers, phosphoric acid production as well as ores used in ceramic production and waste. An integrated method was used in mathematical assumption form for the purpose of calculating the radiation dose equivalent. The calculated values of the annual radiation doses for workers were found to be significant. These results are discussed in the light of international exposure limits for workers

  4. Radiation Doses Received by the Irish Population

    International Nuclear Information System (INIS)

    Some chemical elements present in the environment since the Earth was formed are naturally radioactive and exposure to these sources of radiation cannot be avoided. There have also been additions to this natural inventory from artificial sources of radiation that did not exist before the 1940s. Other sources of radiation exposure include cosmic radiation from outer space and the use of radiation in medical diagnosis and treatment. There can be large variability in the dose received by invividual members of the population from any given source. Some sources of radiation expose every member of the population while, in other cases, only selected individuals may be exposed. For example, natural radioactivity is found in all soils and therefore everybody receives some radiation dose from this activity. On the other hand, in the case of medical exposures, only those who undergo a medical procedure using radiation will receive a radiation dose. The Radiological Protection Institute of Ireland (RPII) has undertaken a comprehensive review of the relevant data on radiation exposure in Ireland. Where no national data have been identified, the RPII has either undertaken its own research or has referred to the international literature to provide a best estimate of what the exposure in Ireland might be. This has allowed the relative contribution of each source to be quantified. This new evaluation is the most up-to-date assessment of radiation exposure and updates the assessment previously reported in 2004. The dose quoted for each source is the annual 'per caput' dose calculated on the basis of the most recently available data. This is an average value calculated by adding the doses received by each individual exposed to a given radiation source and dividing the total by the current population of 4.24 million. All figures have been rounded, consistent with the accuracy of the data. In line with accepted international practice, where exposure takes place both indoors and

  5. Assessment of radiation dose awareness among pediatricians

    International Nuclear Information System (INIS)

    There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians. To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input. Multiple-choice survey. Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%. Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks. (orig.)

  6. Assessment of radiation dose awareness among pediatricians

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Karen E.; Parnell-Parmley, June E.; Charkot, Ellen; BenDavid, Guila; Krajewski, Connie [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, Ontario (Canada); Haidar, Salwa [Mubarak Al-Kabeer Hospital, Department of Radiology, Salmiya (Kuwait); Moineddin, Rahim [University of Toronto, Department of Family and Community Medicine, Toronto (Canada)

    2006-08-15

    There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians. To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input. Multiple-choice survey. Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%. Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks. (orig.)

  7. Estimation of radiation risks at low dose

    International Nuclear Information System (INIS)

    The report presents a review of the effects caused by radiation in low doses, or at low dose rates. For the inheritable (or ''genetic''), as well as for the cancer producing effects of radiation, present evidence is consistent with: (a) a non-linear relationship between the frequency of at least some forms of these effects, with comparing frequencies caused by doses many times those received annually from natural sources, with those caused by lower doses; (b) a probably linear relationship, however, between dose and frequency of effects for dose rates in the region of that received from natural sources, or at several times this rate; (c) no evidence to indicate the existence of a threshold dose below which such effects are not produced, and a strong inference from the mode of action of radiation on cells at low dose rates that no such thresholds are likely to apply to the detrimental, cancer-producing or inheritable, effects resulting from unrepaired damage to single cells. 19 refs

  8. Background internal dose rates of earthworm and arthropod species in the forests of Aomori, Japan

    International Nuclear Information System (INIS)

    We measured naturally occurring radionuclides in samples from an earthworm species and 11 arthropod species collected in coniferous forests in Rokkasho, Aomori, Japan, to assess background internal radiation dose rates. The rates were calculated from the measured concentrations of the radionuclides and dose coefficients from the literature. The mean internal dose rate of composite earthworm samples was 0.35 μGy h-1, whereas the mean dose rates of the arthropod samples ranged from 36 nGy h-1 to 0.79 μGy h-1. Polonium-210 was the radionuclide with the highest contribution to the internal dose rate for all the species, except the longhorn beetle. (author)

  9. Radiation doses from computed tomography in Australia

    International Nuclear Information System (INIS)

    Recent surveys in various countries have shown that computed tomography (CT) is a significant and growing contributor to the radiation dose from diagnostic radiology. Australia, with 332 CT scanners (18 per million people), is well endowed with CT equipment compared to European countries (6 to 13 per million people). Only Japan, with 8500 units (78 per million people), has a significantly higher proportion of CT scanners. In view of this, a survey of CT facilities, frequency of examinations, techniques and patient doses has been performed in Australia. It is estimated that there are 1 million CT examinations in Australia each year, resulting in a collective effective dose of 7000 Sv and a per caput dose of 0.39 mSv. This per caput dose is much larger than found in earlier studies in the UK and New Zealand but is less than 0.48 mSv in Japan. Using the ICRP risk factors, radiation doses from CT could be inducing about 280 fatal cancers per year in Australia. CT is therefore a significant, if not the major, single contributor to radiation doses and possible risk from diagnostic radiology. (authors)

  10. Radiation doses from computed tomography in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, J.E.M.; Tingey, D.R.C

    1997-11-01

    Recent surveys in various countries have shown that computed tomography (CT) is a significant and growing contributor to the radiation dose from diagnostic radiology. Australia, with 332 CT scanners (18 per million people), is well endowed with CT equipment compared to European countries (6 to 13 per million people). Only Japan, with 8500 units (78 per million people), has a significantly higher proportion of CT scanners. In view of this, a survey of CT facilities, frequency of examinations, techniques and patient doses has been performed in Australia. It is estimated that there are 1 million CT examinations in Australia each year, resulting in a collective effective dose of 7000 Sv and a per caput dose of 0.39 mSv. This per caput dose is much larger than found in earlier studies in the UK and New Zealand but is less than 0.48 mSv in Japan. Using the ICRP risk factors, radiation doses from CT could be inducing about 280 fatal cancers per year in Australia. CT is therefore a significant, if not the major, single contributor to radiation doses and possible risk from diagnostic radiology. (authors) 28 refs., 11 tabs., 10 figs.

  11. Patient perspectives on radiation dose.

    Science.gov (United States)

    Graff, Joyce

    2014-03-01

    People with genetic cancer syndromes have a special interest in imaging. They also have special risk factors with respect to radiation. They need to utilize the potential of imaging while keeping in mind concerns about cumulative radiation exposure. Before imaging, early detection of problems was limited. With imaging, issues can be identified when they are small and a good plan of action can be developed early. Operations can be planned and metastatic cancer avoided. The positive contribution of imaging to the care of these patients can be profound. However, this additional surveillance is not without cost. An average patient with 1 of these syndromes will undergo 100 or more scans in their lifetime. Imaging professionals should be able to describe the risks and benefits of each scan in terms that the patient and the ordering physician can understand to make smart decisions about the ordering of scans. Why CT versus MRI? When are x-ray or ultrasound appropriate, and when are they not? What are the costs and the medical risks for the patient? What value does this picture add for the physician? Is there a way to answer the medical question with a test other than a scan? Medicine is a team sport, and the patient is an integral member of the team. PMID:24589397

  12. Environmental policy. Ambient radioactivity levels and radiation doses in 1998

    International Nuclear Information System (INIS)

    The report contains information on the natural (background) radiation exposure (chapter II), the natural radiation exposure as influenced by anthropogenic effects (chapter III), the anthropogenic radiation exposure (chapter IV), and the radiation doses to the environment and the population emanating from the Chernobyl fallout (chapter V). The natural radiation exposure is specified referring to the contributions from cosmic and terrestrial background radiation and intake of natural radioactive substances. Changes of the natural environment resulting from anthropogenic effects (technology applications) inducing an increase in concentration of natural radioactive substances accordingly increase the anthropogenic radiation exposure. Indoor air radon concentration in buildings for instance is one typical example of anthropogenic increase of concentration of natural radioactivity, primarily caused by the mining industry or by various materials processing activities, which may cause an increase in the average radiation dose to the population. Measurements so far show that indoor air concentration of radon exceeds a level of 200 Bq/m3 in less than 2% of the residential buildings; the EUropean Commission therefore recommends to use this concentration value as a maximum value for new residential buildings. Higher concentrations are primarily measured in areas with relevant geological conditions and abundance of radon, or eg. in mining areas. (orig./CB)

  13. Radiation doses in interventional radiology procedures

    International Nuclear Information System (INIS)

    Objective: To investigate the radiation doses for the patients undergoing interventional radiology and to analyze the dose - influencing factors. Methods: The clinical data of 461 patients undergoing interventional radiology, including cerebral angiography (CEA), cerebral aneurysm embolism (CAE), superselective hepatic arterial chemoembolization (SHAG), coronary angiography (COA), percutaneous intracoronary stent implantation (PISI), cardiac radiofrequency catheter ablation (RFCA), and permanent cardiac pacemaker implantation (PCPI) were collected to observe the cumulative air kerma (CAK), dose area product (DAP), and fluoroscopy time, and effective dose was estimated using the conversion factors. Results: The effective doses for CEA, CAE, SHAG, COA, PISI, RFCA, and PCPI were (0.33 ±0.20), (0.49 ±0.35), (6.92 ±4.19),(0.76 ±0.91), (2.35 ± 1.47), (0.50 ±0.74), and (0.67 ±0.70) Sv,respectively. In 126 of the 416 patients (26%), the effective doses were greater than 1 Sv, and the effective doses of 10 person-times were greater than 10 Sv, all of which were observed in the patients undergoing SHAG. The CAK values for CEA, CAE, SHAG, COA, PISI, RFCA, and PCPI were (0.55 ±0.43), (1.34 ± 1.11), (0.95 ±0.57), (0.32 ±0.31), (0.91 ±0.33), (0.16 ±0.22), and (0.15 ±0.14) Gy, respectively. The CAK values were greater than 1 Gy in 59 of the 461 patients (12.8%), greater than 2 Gy in 11 cases (2.4%), and greater than 3 Gy in 1 CEA cases and 1 CEA case, respectively. Conclusions: There is a wide variation range in radiation dose for different procedures. As most interventional radiology procedure can result in clinically significant radiation dose to the patient, stricter dose control should be carried out. (authors)

  14. An Evaluation of Dose Equivalence between Synchrotron Microbeam Radiation Therapy and Conventional Broadbeam Radiation Using Clonogenic and Cell Impedance Assays

    OpenAIRE

    Mohammad Johari Ibahim; Crosbie, Jeffrey C.; Yuqing Yang; Marina Zaitseva; Andrew W Stevenson; Rogers, Peter A. W.; Premila Paiva

    2014-01-01

    BACKGROUND: High-dose synchrotron microbeam radiation therapy (MRT) has shown the potential to deliver improved outcomes over conventional broadbeam (BB) radiation therapy. To implement synchrotron MRT clinically for cancer treatment, it is necessary to undertake dose equivalence studies to identify MRT doses that give similar outcomes to BB treatments. AIM: To develop an in vitro approach to determine biological dose equivalence between MRT and BB using two different cell-based assays. METHO...

  15. Correlation between regional oncological mortality and natural radiation background in the CSR

    International Nuclear Information System (INIS)

    On the basis of published geological data (maps) an attempt was made to correlate the regional distribution of oncological mortality with the dose rate of the natural radiation background in the Czech Socialist Republic. No relationship was observed between the two parameters in the whole area of the CSR; for districts with an increased dose rate of the background or with high mortality the statistical relationship proved an inverse relationship: the higher the background dose rate the lower the oncological mortality and vice versa. (author). 3 figs., 1 tab., 22 refs

  16. Radiation dose in temporomandibular joint zonography

    Energy Technology Data Exchange (ETDEWEB)

    Coucke, M.E.; Bourgoignie, R.R.; Dermaut, L.R.; Bourgoignie, K.A.; Jacobs, R.J. (Department of Orthodontics, Universitair Ziekenhuis, Ghent (Belgium))

    1991-06-01

    Temporomandibular joint morphology and function can be evaluated by panoramic zonography. Thermoluminescent dosimetry was applied to evaluate the radiation dose to predetermined sites on a phantom eye, thyroid, pituitary, and parotid, and the dose distribution on the skin of the head and neck when the TMJ program of the Zonarc panoramic x-ray unit was used. Findings are discussed with reference to similar radiographic techniques.

  17. Epigenomic Adaptation to Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Michael N. [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-30

    The overall hypothesis of this grant application is that the adaptive responses elicited by low dose ionizing radiation (LDIR) result in part from heritable DNA methylation changes in the epigenome. In the final budget period at the University of Wisconsin-Madison, we will specifically address this hypothesis by determining if the epigenetically labile, differentially methylated regions (DMRs) that regulate parental-specific expression of imprinted genes are deregulated in agouti mice by low dose radiation exposure during gestation. This information is particularly important to ascertain given the 1) increased human exposure to medical sources of radiation; 2) increased number of people predicted to live and work in space; and 3) enhanced citizen concern about radiation exposure from nuclear power plant accidents and terrorist ‘dirty bombs.’

  18. Imaging of Radiation Dose for Stereotactic Radiosurgery.

    Science.gov (United States)

    Guan, Timothy Y; Almond, Peter R; Park, Hwan C; Lindberg, Robert D; Shields, Christopher B

    2015-01-01

    The distributions of radiation dose for stereotactic radiosurgery, using a modified linear accelerator (Philips SL-25 and SRS-200), have been studied by using three different dosimeters: (1) ferrous-agarose-xylenol orange (FAX) gels, (2) TLD, and (3) thick-emulsion GafChromic dye film. These dosimeters were loaded into a small volume of defect in a phantom head. A regular linac stereotactic radiosurgery treatment was then given to the phantom head for each type of dosimeter. The measured radiation dose and its distributions were found to be in good agreement with those calculated by the treatment planning computer. PMID:27421869

  19. High dose dosimetry for radiation processing

    International Nuclear Information System (INIS)

    Radiation processing today offers various advantages in the field of sterilization of medical and pharmaceutical products, food preservation, treatment of chemical materials and a variety of other products widely used in modern society, all of which are of direct relevance to health and welfare. The safety and economic importance of radiation processing is clearly recognized. It is understood that reliable dosimetry is a key parameter for quality assurance of radiation processing and irradiated products. Furthermore, the standardization of dosimetry can provide a justification for the regulatory approval of irradiated products and form the basis of international clearance for free trade. After the initiation of the Agency's high dose standardization programme (1977), the first IAEA Symposium on High Dose Dosimetry was organized in 1984. As a result, concern as to the necessity of reliable dosimetry has greatly escalated not only in the scientific community but also in the radiation processing industry. The second International Symposium on High Dose Dosimetry for Radiation Processing was held in Vienna from 5 to 9 November, 1990, with a view to providing an international forum for the exchange of technical information on up to date developments in this particular field. The scientific programme held promises for an authoritative account of the status of high dose dosimetry throughout the world in 1990. Forty-one papers presented at the meeting discussed the development of new techniques, the improvement of reference and routine dosimetry systems, and the quality control and assurance of dosimetry. Refs, figs and tabs

  20. Evaluation of High Level Environmental Background Radiation Areas and its Variation in Ramsar

    Directory of Open Access Journals (Sweden)

    Tayyeb Allahverdi Pourfallah

    2012-03-01

    Full Text Available Introduction The exposure of human beings to ionizing radiation from natural sources is a continuing and inescapable feature of life on earth. For most individuals, this exposure exceeds that from all man-made sources combined. Materials and Methods In this study, the annual effective dose in high level environmental background radiation areas (HLEBRAs of northern city of Ramsar in Iran was determined. For dosimetry, a gamma radiation dosimeter was used. Measurements were performed in more than 90 points in five districts with HLEBR around and near hot springs. Results In some areas, the annual effective dose from outdoor external gamma radiation in HLEBRAs (30 mSv/y exceeded the annual effective dose limit for radiation workers. Our results are evident that the population dose from normal background radiation in HLEBRAs is 200 times higher than corresponding values in Ramsar sea shore. To estimate the cosmic ray contribution, dose measurements were performed on the sea surface one km off the sea shore. Conclusion The observed differences over locations and measured doses between this study and the others revealed the dynamic nature of this phenomenon, and necessitate performing the periodic studies in these areas. Moreover, cytogenetic and immunologic researches for studying the long term effects of these high level environmental radiations on the residents of these HLEBRAs are necessary.

  1. Systematic review on physician's knowledge about radiation doses and radiation risks of computed tomography

    International Nuclear Information System (INIS)

    Background: The frequent use of computed tomography is a major cause of the increasing medical radiation exposure of the general population. Consequently, dose reduction and radiation protection is a topic of scientific and public concern. Aim: We evaluated the available literature on physicians' knowledge regarding radiation dosages and risks due to computed tomography. Methods: A systematic review in accordance with the Cochrane and PRISMA statements was performed using eight databases. 3091 references were found. Only primary studies assessing physicians' knowledge about computed tomography were included. Results: 14 relevant articles were identified, all focussing on dose estimations for CT. Overall, the surveys showed moderate to low knowledge among physicians concerning radiation doses and the involved health risks. However, the surveys varied considerably in conduct and quality. For some countries, more than one survey was available. There was no general trend in knowledge in any country except a slight improvement of knowledge on health risks and radiation doses in two consecutive local German surveys. Conclusions: Knowledge gaps concerning radiation doses and associated health risks among physicians are evident from published research. However, knowledge on radiation doses cannot be interpreted as reliable indicator for good medical practice.

  2. Car-borne survey of natural background gamma dose rate in Çanakkale region, Turkey.

    Science.gov (United States)

    Turhan, S; Arıkan, I H; Oğuz, F; Özdemir, T; Yücel, B; Varinlioğlu, A; Köse, A

    2012-01-01

    Natural background gamma radiation was measured along roads in the environs of Çanakkale region by using a car-borne spectrometer system with a plastic gamma radiation detector. In addition, activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K in soil samples from the Çanakkale region were determined by using a gamma spectrometer with an HPGe detector. A total of 92,856 data of the background gamma dose rate were collected for the Çanakkale region. The background gamma dose rate of the Çanakkale region was mapped using ArcGIS software, applying the geostatistical inverse distance-weighted method. The average and population-weighted average of the gamma dose are 55.4 and 40.6 nGy h⁻¹, respectively. The corresponding average annual effective dose to the public ranged from 26.6 to 96.8 µSv. PMID:21362693

  3. Background radiation and childhood leukemia: A nationwide register-based case-control study.

    Science.gov (United States)

    Nikkilä, Atte; Erme, Sini; Arvela, Hannu; Holmgren, Olli; Raitanen, Jani; Lohi, Olli; Auvinen, Anssi

    2016-11-01

    High doses of ionizing radiation are an established cause of childhood leukemia. However, substantial uncertainty remains about the effect of low doses of radiation, including background radiation and potential differences between genetic subgroups of leukemia have rarely been explored. We investigated the effect of the background gamma radiation on childhood leukemia using a nationwide register-based case-control study. For each of the 1,093 cases, three age- and gender matched controls were selected (N = 3,279). Conditional logistic regression analyses were adjusted for confounding by Down syndrome, birth weight (large for gestational age), and maternal smoking. Complete residential histories and previously collected survey data of the background gamma radiation in Finland were used to assess the exposure of the study subjects to indoor and outdoor gamma radiation. Overall, background gamma radiation showed a non-significant association with the OR of childhood leukemia (OR 1.01, 95% CI 0.97, 1.05 for 10 nSv/h increase in average equivalent dose rate to red bone marrow). In subgroup analyses, age group 2-childhood leukemia, particularly at age 2-<7 years. Our findings suggest a larger effect of radiation on leukemia with high hyperpdiploidy than other subgroups, but this result requires further confirmation. PMID:27405274

  4. Effects of Proton Radiation Dose, Dose Rate and Dose Fractionation on Hematopoietic Cells in Mice

    OpenAIRE

    Ware, J.H.; Sanzari, J.; Avery, S.; Sayers, C; Krigsfeld, G.; Nuth, M.; Wan, X. S.; Rusek, A.; Kennedy, A R

    2010-01-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05–0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals...

  5. Cosmic far-ultraviolet background radiation

    International Nuclear Information System (INIS)

    It is demonstrated that interstellar dust grains forward-scatter far-ultraviolet radiation extremely strongly: the value of the Henyey-Greenstein scattering parameter g at 1425 A is shown to be at least 0.75; the actual value is very likely greater than 0.9. Also, observations of the Virgo cluster of galaxies sets a limit tau > 2 x 1025 sec on the life-time of 17-20 eV/c2 heavy neutrinos, if such neutrinos are responsible for the gravitational binding of the cluster. (Auth.)

  6. Measurement of radiation dose at the north interaction point of BEPCⅡ

    Institute of Scientific and Technical Information of China (English)

    MO Xiao-Hu; ZHANG Jian-Yong; ZHANG Tian-Bao; ZHANG Qing-Jiang; Achasov Mikhail; FU Cheng-Dong; Muchnoi Nikolay; QIN Qing; QU Hua-Min; WANG Yi-Fang; WU Jing-Min; XU Jin-Qiang; YU Bo-Xiang

    2009-01-01

    The technique details for measuring radiation dose are expounded.The results of gamma and neutron radiation levels are presented and the corresponding radiation shielding is discussed based on the simplified estimation.In addition, the photon radiation level move as background for future experiments is measured by a NaI(T1) detector.

  7. Background Radiation Studies at LHCb Using Geant4

    CERN Document Server

    Daquino, G G; Folger, G

    2004-01-01

    This paper aims to describe the feasibility studies performed to evaluate the background radiation levels in the LHCb experiment with Geant4. LHCb is one of the experiments that will operate at the LHC (Large Hadron Collider) under construction at CERN. The simulation toolkit Geant4 has been used to model the interactions of particles with the detector. Geant4 is a software toolkit developed and maintained by a world-wide collaboration of physicists and computer scientists. The principal monitored distributions in this study are the dose and the fluence of certain particles in specific locations of the experiment. The dose is defined as the energy delivered in a volume per unit of the volume mass, while the fluence is defined as the number of particles passing through a surface per unit of area. Energy spectra need also to be evaluated to take into account the energy distribution of these particles, since specific problems in the electronics can be caused by particles of certain energies. For ...

  8. Radiation doses and risks from internal emitters

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, John [Health Protection Agency, Radiation Protection Division, CRCE, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom); Day, Philip [School of Chemistry, University of Manchester, Manchester M13 9PL (United Kingdom)], E-mail: john.harrison@hpa.org.uk, E-mail: philip.day@manchester.ac.uk

    2008-06-01

    This review updates material prepared for the UK Government Committee Examining Radiation Risks from Internal Emitters (CERRIE) and also refers to the new recommendations of the International Commission on Radiological Protection (ICRP) and other recent developments. Two conclusions from CERRIE were that ICRP should clarify and elaborate its advice on the use of its dose quantities, equivalent and effective dose, and that more attention should be paid to uncertainties in dose and risk estimates and their implications. The new ICRP recommendations provide explanations of the calculation and intended purpose of the protection quantities, but further advice on their use would be helpful. The new recommendations refer to the importance of understanding uncertainties in estimates of dose and risk, although methods for doing this are not suggested. Dose coefficients (Sv per Bq intake) for the inhalation or ingestion of radionuclides are published as reference values without uncertainty. The primary purpose of equivalent and effective dose is to enable the summation of doses from different radionuclides and from external sources for comparison with dose limits, constraints and reference levels that relate to stochastic risks of whole-body radiation exposure. Doses are calculated using defined biokinetic and dosimetric models, including reference anatomical data for the organs and tissues of the human body. Radiation weighting factors are used to adjust for the different effectiveness of different radiation types, per unit absorbed dose (Gy), in causing stochastic effects at low doses and dose rates. Tissue weighting factors are used to take account of the contribution of individual organs and tissues to overall detriment from cancer and hereditary effects, providing a simple set of rounded values chosen on the basis of age- and sex-averaged values of relative detriment. While the definition of absorbed dose has the scientific rigour required of a basic physical quantity

  9. Effects of deprivation of background environmental radiation on cultured human cells

    International Nuclear Information System (INIS)

    In this paper we present results from an experiment aimed at investigating whether living cells are influenced by background ionizing radiation. Parallel human cell cultures were set-up in two separate laboratories and maintained for several months under identical conditions but for a 80 x different level of background ionizing radiation. Periodically, the cell cultures were monitored for the onset of divergences in biochemical behavior, using two distinct cellular biology assays, namely micronuclei induction and activity of enzymes implicated in the management of oxidative stress. To reveal any subtle modifications, responses were also amplified by subjecting cell cultures to acute stress induced by exposure to moderately high doses of ionizing radiation. Compared to reference radiation background conditions, cultures maintained in a reduced background radiation environment handled the consequences of acute stress with diminished efficacy.

  10. Bio-indicators for radiation dose assessment

    International Nuclear Information System (INIS)

    In nuclear facilities, such as Chalk River Laboratories, dose to the atomic radiation workers (ARWs) is assessed routinely by using physical dosimeters and bioassay procedures in accordance with regulatory recommendations. However, these procedures may be insufficient in some circumstances, e.g., in cases where the reading of the physical dosimeters is questioned, in cases of radiation accidents where the person(s) in question was not wearing a dosimeter, or in the event of a radiation emergency when an exposure above the dose limits is possible. The desirability of being able to assess radiation dose on the basis of radio-biological effects has prompted the Dosimetric Research Branch to investigate the suitability of biological devices and techniques that could be used for this purpose. Current biological dosimetry concepts suggest that there does not appear to be any bio-indicator that could reliably measure the very low doses that are routinely measured by the physical devices presently in use. Nonetheless, bio-indicators may be useful in providing valuable supplementary information in cases of unusual radiation exposures, such as when the estimated body doses are doubtful because of lack of proper physical measurements, or in cases where available results need to be confirmed for medical treatment plannings. This report evaluates the present state of biological dosimetry and, in particular, assesses the efficiency and limits of individual indicators. This has led to the recommendation of a few promising research areas that may result in the development of appropriate biological dosimeters for operational and emergency needs at Chalk River

  11. Bayesian approach in MN low dose of radiation counting

    International Nuclear Information System (INIS)

    The Micronucleus assay in lymphocytes is a well established technique for the assessment of genetic damage induced by ionizing radiation. Due to the presence of a natural background of MN the net MN is obtained by subtracting this value to the gross value. When very low doses of radiation are given the induced MN is close even lower than the predetermined background value. Furthermore, the damage distribution induced by the radiation follows a Poisson probability distribution. These two facts pose a difficult task to obtain the net counting rate in the exposed situations. It is possible to overcome this problem using a bayesian approach, in which the selection of a priori distributions for the background and net counting rate plays an important role. In the present work we make a detailed analysed using bayesian theory to infer the net counting rate in two different situations: a) when the background is known for an individual sample, using exact value value for the background and Jeffreys prior for the net counting rate, and b) when the background is not known and we make use of a population background distribution as background prior function and constant prior for the net counting rate. (Author)

  12. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    Directory of Open Access Journals (Sweden)

    Sergio Luevano-Gurrola

    2015-09-01

    Full Text Available Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize.

  13. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    Science.gov (United States)

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-01-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  14. Patient radiation doses from neuroradiology procedures

    International Nuclear Information System (INIS)

    Following the presentation of radiation-induced deterministic effects by some patients undergoing neuroradiological procedures during successive sessions, such as temporary epilation, in the 'Hospital Universitario de Canarias', measurements were made of dose to patients. The maximum dose-area product measured by ionization chamber during these procedures was 39617 cGy.cm2 in a diagnostic of aneurysm and the maximum dose to the skin measured by thermoluminescent dosemeters (TLDs) was 462.53 mGy. This can justify certain deterministic effects but it is unlikely that the patients will suffer serious effects from this skin dose. Also, measurements were made of effective dose about two usual procedures, embolisation of tumour und embolisation of aneurysm. These procedures were reproduced with an anthropomorphic phantom Rando and doses were measured with TLDs. Effective doses obtained were 3.79 mSv and 4.11 mSv, respectively. The effective dose valued by the program EFFDOSE was less than values measured with TLDs. (author)

  15. Simple dose verification system for radiotherapy radiation

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate an accurate and convenient quality assurance programme that should be included in the dosimetry system of the radiotherapy level radiation. We designed a mailed solid phantom and used TLD-100 chips and a Rexon UL320 reader for the purpose of dosimetry quality assurance in Taiwanese radiotherapy centers. After being assembled, the solid polystyrene phantom weighted only 375 g which was suitable for mailing. The Monte Carlo BEAMnrc code was applied in calculations of the dose conversion factor of water and polystyrene phantom: the dose conversion factor measurements were obtained by switching the TLDs at the same calibration depth of water and the solid phantom to measure the absorbed dose and verify the accuracy of the theoretical calculation results. The experimental results showed that the dose conversion factors from TLD measurements and the calculation values from the BEAMnrc were in good agreement with a difference within 0.5%. Ten radiotherapy centers were instructed to deliver to the TLDs on central beam axis absorbed dose of 2 Gy. The measured doses were compared with the planned ones. A total of 21 beams were checked. The dose verification differences under reference conditions for 60Co, high energy X-rays of 6, 10 and 15 MV were truly within 4% and that proved the feasibility of applying the method suggested in this work in radiotherapy dose verification

  16. Imputability of health effects to low-dose radiation exposure situations

    International Nuclear Information System (INIS)

    The key note address is aimed to discuss a crucial issue in nuclear law: whether or not late health effects of stochastic nature, such as radio-induced cancer or hereditable effects, are attributable to radiation exposure situations delivering relatively low radiation doses and, therefore, whether such effects are imputable to those responsible of such situations. The term low dose is used in the presentation when referring to doses similar to natural background doses. (author)

  17. Experiences from studies of leukemia, background radiation and other factors

    International Nuclear Information System (INIS)

    Ionizing radiation seems to induce myeloid leukemia of the acute and chronic type, and also acute lymphatic leukemia but not chronic lymphatic leukemia. The effects of low dose radiation in this context as well as for other malignancies, are currently a matter of controversy. On the basis of literary data the carcinogenic effect, and in particular the leukemia inducing effect, of low dose irradiation is discussed. It is concluded that only further studies in the low dose range can create a definite basis for a risk assessment with regard to ionizing radiation. The risk estimates obtained may not necessarily reflect an initiating effect of ionizing radiation, but could involve late stage effects exerted over time. However, such possibilities have so far achieved little attention

  18. Radiation Dose Optimization For Critical Organs

    Science.gov (United States)

    Khodadadegan, Yasaman

    Ionizing radiation used in the patient diagnosis or therapy has negative effects on the patient body in short term and long term depending on the amount of exposure. More than 700,000 examinations are everyday performed on Interventional Radiology modalities, however; there is no patient-centric information available to the patient or the Quality Assurance for the amount of organ dose received. In this study, we are exploring the methodologies to systematically reduce the absorbed radiation dose in the Fluoroscopically Guided Interventional Radiology procedures. In the first part of this study, we developed a mathematical model which determines a set of geometry settings for the equipment and a level for the energy during a patient exam. The goal is to minimize the amount of absorbed dose in the critical organs while maintaining image quality required for the diagnosis. The model is a large-scale mixed integer program. We performed polyhedral analysis and derived several sets of strong inequalities to improve the computational speed and quality of the solution. Results present the amount of absorbed dose in the critical organ can be reduced up to 99% for a specific set of angles. In the second part, we apply an approximate gradient method to simultaneously optimize angle and table location while minimizing dose in the critical organs with respect to the image quality. In each iteration, we solve a sub-problem as a MIP to determine the radiation field size and corresponding X-ray tube energy. In the computational experiments, results show further reduction (up to 80%) of the absorbed dose in compare with previous method. Last, there are uncertainties in the medical procedures resulting imprecision of the absorbed dose. We propose a robust formulation to hedge from the worst case absorbed dose while ensuring feasibility. In this part, we investigate a robust approach for the organ motions within a radiology procedure. We minimize the absorbed dose for the critical

  19. Agriculture-related radiation dose calculations

    International Nuclear Information System (INIS)

    Estimates of radiation dose to the public must be made at each stage in the identification and qualification process leading to siting a high-level nuclear waste repository. Specifically considering the ingestion pathway, this paper examines questions of reliability and adequacy of dose calculations in relation to five stages of data availability (geologic province, region, area, location, and mass balance) and three methods of calculation (population, population/food production, and food production driven). Calculations were done using the model PABLM with data for the Permian and Palo Duro Basins and the Deaf Smith County area. Extra effort expended in gathering agricultural data at succeeding environmental characterization levels does not appear justified, since dose estimates do not differ greatly; that effort would be better spent determining usage of food types that contribute most to the total dose; and that consumption rate and the air dispersion factor are critical to assessment of radiation dose via the ingestion pathway. 17 refs., 9 figs., 32 tabs

  20. Agriculture-related radiation dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Furr, J.M.; Mayberry, J.J.; Waite, D.A.

    1987-10-01

    Estimates of radiation dose to the public must be made at each stage in the identification and qualification process leading to siting a high-level nuclear waste repository. Specifically considering the ingestion pathway, this paper examines questions of reliability and adequacy of dose calculations in relation to five stages of data availability (geologic province, region, area, location, and mass balance) and three methods of calculation (population, population/food production, and food production driven). Calculations were done using the model PABLM with data for the Permian and Palo Duro Basins and the Deaf Smith County area. Extra effort expended in gathering agricultural data at succeeding environmental characterization levels does not appear justified, since dose estimates do not differ greatly; that effort would be better spent determining usage of food types that contribute most to the total dose; and that consumption rate and the air dispersion factor are critical to assessment of radiation dose via the ingestion pathway. 17 refs., 9 figs., 32 tabs.

  1. Committed dose assessment based on background outdoor gamma exposure in Chihuahua City, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Luevano G, S.; Perez T, A.; Pinedo A, C.; Renteria V, M. [Universidad Autonoma de Chihuahua, Facultad de Zootecnia y Ecologia, Perif. Francisco R. Almada Km 1, 31415 Chihuahua, Chih. (Mexico); Carrillo F, J.; Montero C, M. E., E-mail: mrenteria@uach.mx [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, 31136 Chihuahua, Chih. (Mexico)

    2015-10-15

    Full text: Determining ionizing radiation in a geographic area serves to assess its effects on populations health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the committed dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, annual effective dose, and the lifetime cancer risk, 48 sampling points were randomly selected along the Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Muller counter. At the same sites, 48 soil samples were taken to obtain the activity concentrations of {sup 226}Ra, {sup 232}Th, {sup 40}K and their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Outdoor gamma dose rates ranged from 56 to 193 n Gy h{sup -1}. Results indicated that lifetime effective dose to inhabitants of Chihuahua City is in average of 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of activity concentrations in soil were 51.8, 73.1, and 1096.5 Bq kg{sup -1}, of {sup 226}Ra, {sup 232}Th and {sup 40}K, respectively. From the analysis of the spatial distribution of {sup 232}Th, {sup 226}Ra, and {sup 40}K is to north, to north-center, and to south of city, respectively. In conclusion, natural background gamma dose received by inhabitants of Chihuahua City is high and mainly due to geological characteristics of the zone. (Author)

  2. Natural background radiation induces cytogenetic radioadaptive response more effectively than occupational exposure in human peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Ramsar, a city in the north part of Iran, has the highest level of natural background radiation in the world. We compared induction of cytogenetic radioadaptive response by High Natural Background Radiation (HNBR) in Ramsar and X-Ray occupational exposure as inducing doses in human peripheral blood lymphocytes. 30 healthy control individuals, living in Ramsar but in ordinary background radiation areas (inducing dose = 0), 15 healthy individuals from Talesh Mahalleh, a region with extraordinary level of background radiation (max. inducing dose = 260 mGy/year) and 7 X-Ray radiographers working in Ramsar hospital located in normal natural background of ionising radiation (max. inducing dose = 20 mGy/year) were evaluated. Peripheral blood samples were prepared and exposed to challenge dose of 0 and 2 Gy. Lymphocytes were scored using analysis of metaphase, for the presence of chromosomal aberrations (simple deletion, dicentrics and rings). An adaptive response was observed in HNBR and radiation workers groups in comparison with sham controls. Also, compared with occupationally exposed group a significant marked increase in adaptive response was observed in HNBR group. These findings indicate that both natural background radiation and occupational exposure could induce cytogenetic radioadaptive response and it is more significant regarding to natural background ionising radiation. (author)

  3. Stimulating effects of low doses of radiation

    International Nuclear Information System (INIS)

    Different ionizing radiations cause biochemical and biophysical changes in the cells of the genotypes according to the application of the doses applied to different organs of the plants, and the manner of their application (acute, chronic, or acute and chronic). The sensitivity of different genotypes, and their tissues, depends on the stage at which their tissues were irradiated as well as on the environmental conditions under which the irradiation was made. Relatively strong doses usually cause some genetic changes in the somatic and generative cells. Small doses can, in some genotypes, stimulate the growth of some tissues to some extent. The stimulating effect on the growth of seedlings of the M2 generation, developed from acute seed irradiation of some genotypes of wheat, barley, and inbred lines of maize and their hybrids is described here. 3 refs, 5 tabs

  4. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; D. Nielsen, Kamilla;

    2015-01-01

    might avoid including the eye in the CT scan without losing sufficient visualization of the scull base. The aim of this study was to evaluate the possibility of decreasing the radiation dose to the eye lens, simply by changing the head position, when doing the PET/CT scan from the base of the scull...... to the proximal femur. Methods and materials: The study was performed using a human like whole body phantom with electronic dosimetry units placed upon each eye to detect the exact radiation dose to the eye lens during each scan. The phantom’s head was placed in two different positions, (a) elevated with a small...... pillow below the head (standard), and (b) kipped backwards with the pillow below the neck (kipped). For each head position, CT scans were repeated 5 times with both a low dose and a high dose CT protocol; in this way, a total of 20 CT scans were performed. Robust standard errors were used in order...

  5. Low radiation doses - Book of presentations (slides)

    International Nuclear Information System (INIS)

    This document brings together all the available presentations (slides) of the conference on low radiation doses organised by the 'research and health' department of the French society of radiation protection (SFRP). Ten presentations are available and deal with he following topics: 1 - Cyto-toxicity, geno-toxicity: comparative approach between ionizing radiations and other geno-toxic agents (F. Nesslany, Institut Pasteur, Lille); Succession of events occurring after a radio-induced DNA damage (D. Averbeck, IRSN/CEA); Importance of stem cells in the response to ionizing radiations (J. Lebeau, CEA); Relation between energy deposition at the sub-cell scale and early biological effects (C. Villagrasa, IRSN); Natural history of breast cancer: predisposition, susceptibility with respect to irradiation (S. Rivera, IGR); Pediatrics scanner study and the EPI-CT project (M.O Bernier, IRSN); What future for an irradiated cell: survival or apoptosis? (E. Sage, Institut Curie); Differential effect of a 137Cs chronic contamination on the different steps of the atheromatous pathology (T. Ebrahimian, IRSN); Variability of the individual radiosensitivity (S. Chevillard, CEA); What definitions for individual sensitivity? (A. Schmidt, CEA); Low doses: some philosophical remarks (A. Grinbaum, CEA)

  6. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

  7. Low Dose Ionizing Radiation Modulates Immune Function

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Gregory A. [Loma Linda Univ., CA (United States)

    2016-01-12

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a “Th2 polarized” immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in the

  8. Measurements of background gamma radiation on Spacelab 2

    Science.gov (United States)

    Fishman, G. J.; Paciesas, W. S.; Gregory, J. C.

    1987-01-01

    A nuclear radiation monitor (NRM) which was flown as part of the verification instrumentation on the Spacelab 2 mission (July 29 - August 6, 1985) recorded spectra every 20 seconds and counting rates in coarse energy bands on finer time scales. The gamma radiation environment on Spacelab is characterized by cosmic-ray and trapped proton secondary radiation in the Spacelab/Shuttle, earth albedo radiation, and delayed induced radioactivity in the detector and surrounding materials. It is found that passages through South Atlantic Anomaly protons produce a well-defined background enhancement.

  9. BCC and Childhood Low Dose Radiation

    Directory of Open Access Journals (Sweden)

    Arash Beiraghi Toosi

    2014-10-01

    Full Text Available Skin cancer is a late complication of ionizing radiation. Two skin neoplasms prominent Basal Cell Carcinoma (BCC and Squamous Cell Carcinoma (SCC are the most famous complications of radiotherapy. Basal Cell Carcinoma (BCC is the most common human malignant neoplasm. Many genetic and environmental factors are involved in its onset. BCC is observed in sun-exposed areas of skin. Some patients with scalp BCC have had a history of scalp radiation for the treatment of tinea capitis in childhood. Evidence that ionizing radiation is carcinogenic first came from past reports of nonmelanoma skin cancers on the hands of workers using radiation devices. The total dose of radiation and irradiated site exposed to sunlight can lead to a short incubation period. It is not clear whether BCC in these cases has a more aggressive nature and requires a more aggressive resection of the lesion. The aim of this review was to evaluate the differences between BCC specification and treatment results between irradiated and nonirradiated patients.

  10. Ultraviolet radiation therapy and UVR dose models

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, David Robert, E-mail: davidrobert.grimes@oncology.ox.ac.uk [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland and Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom)

    2015-01-15

    Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed.

  11. Radiation doses from medical diagnostic procedures in Canada

    International Nuclear Information System (INIS)

    This document sets out to record and analyze the doses incurred in Canada from medical procedures involving the use of ionizing radiation in a typical year. Excluded are those doses incurred during therapeutic irradiation, since they differ in scale to such a large degree and because they are used almost exclusively in treating cancer. In this we are following a precedent set by the United Nations Scientific Committee on the Effects of Ionizing Radiation. Although the International Commission on Radiological Protection (ICRP) notes that dose limits should not be applied to medical exposures, it also observes that doses in different settings for the same procedure may vary by as much as two orders of magnitude, and that there are considerable opportunities for dose reductions in diagnostic radiology. Because these data do not stand in isolation the report also encompasses a review of the relevant literature and some background comment on the evolving technology of the radiological sciences. Because there is a somewhat incomplete perception of the changes taking place in diagnostic methods we have also provided some introductory explanations of the relevant technologies. In addition, there is an analysis of at least some of the limitations on the completeness of the data which are reported here. (author)

  12. Therapeutic effects of low radiation doses

    International Nuclear Information System (INIS)

    This editorial explores the scientific basis of radiotherapy with doses of < 1 Gy for various non-malignant conditions, in particular dose-effect relationships, risk-benefit considerations and biological mechanisms. A review of the literature, particularly clinical and experimental reports published more than 50 years ago was conducted to clarify the following problems. 1. The dose-response relationships for the therapeutic effects on three groups of conditions: non-malignant skin disease, arthrosis and other painful degenerative joint disorders and anti-inflammatory radiotherapy; 2. risks after radiotherapy and after the best alternative treatments; 3. the biological mechanisms of the different therapeutic effects. Radiotherapy is very effective in all three groups of disease. Few dose-finding studies have been performed, all demonstrating that the optimal doses are considerable lower than the generally recommended doses, yet few of these studies meet the required standard. In different conditions, risk-benefit analysis of radiotherapy versus the best alternative treatment yields very different results: whereas radiotherapy for acute postpartum mastitis may not be justified any more, the risk-benefit ratio of radiotherapy of other conditions and particularly so in dermatology and some anti-inflammatory radiotherapy appears to be more favourable than the risk-benefit ratio of the best alternative treatments. Radiotherapy can be very effective treatment for various non-malignant conditions such as eczema, psoriasis, periarthritis humeroscapularis, epicondylitis, knee arthrosis, hydradenitis, parotitis and panaritium and probably be associated with less acute and long-term side effects than similarly effective other treatments. Randomized clinical studies are required to find the optimal dosage which, at present, may be unnecessarily high. Since no adequate experimental studies have been performed nothing is known about the mechanisms of these therapeutic radiation

  13. Radiation dose assessment in nuclear medicine

    International Nuclear Information System (INIS)

    Radionuclides are used in nuclear medicine in a variety of diagnostic and therapeutic procedures. Recently, interest has grown in therapeutic agents for a number of applications in nuclear medicine. Internal dose models and methods have been in use for many years, are well established and can give radiation doses to stylized models representing reference individuals. Kinetic analyses need to be carefully planned, and dose conversion factors should be chosen that are most similar to the subject in question and that can then be tailored to be more patient specific. Such calculations, however, are currently not relevant in patient management in internal emitter therapy, as they are not sufficiently accurate or detailed to guide clinical decision making. Great strides are being made at many centres regarding the use of patient image data to construct individualized voxel based models for more detailed and patient specific dose calculations.These recent advances make it likely that the relevance will soon change to be more similar to that of external beam treatment planning. (author)

  14. Radiation doses from mammography in Australia

    International Nuclear Information System (INIS)

    During 1989-90 the Australian Radiation Laboratory conducted a postal survey of at least 90% of the mammographic facilities in Australia. The primary aim of the survey was to measure the mean glandular dose (MGD) and the X-ray beam half value layer (HVL) for a typical mammograph. The MGD and HVL were measured with a specially designed tissue equivalent monitor. In all, 258 mammographic centres were surveyed. It was found that for centres using film-screen imaging, the average mean glandular dose was 1.83 mGy for centres using grids and 0.84 mGy for centres not using grids. In addition to the MGD and HVL, comprehensive statistical information was collected and data is presented on the types of equipment and techniques used, the number and age of patients and demographic distribution of centres. Results indicate that the use of a grid is the major factor determining dose and several other factors appear to have minor effects. In view of the distribution of MGD, it is recommended that the mean glandular dose per image, for a 5 cm compressed breast thickness, should not exceed 2.0 mGy when a grid is used and 1.0 mGy without a grid. 63 refs., 11 tabs., 15 figs

  15. Optimization of image quality and radiation dose in neuroradiological computed tomography

    OpenAIRE

    Löve, Askell

    2013-01-01

    Background: The goal of clinical computed tomography (CT) is to produce images of diagnostic quality using the lowest possible radiation exposure. Degradation of image quality, with increased image noise and reduced spatial resolution, is a major limitation for radiation dose reduction in CT. This can be counteracted with new post-processing image filters and iterative reconstruction (IR) algorithms that improve image quality and allow for reduced radiation doses. Implementation of new method...

  16. To understand the radiation dose in color

    International Nuclear Information System (INIS)

    Radiation is particles or electromagnetic waves having high energy, causing health damage to the human body, but cannot be perceived by the five senses of human. For enabling the visual sensing of radiation, the research and development of the functional dye material that changes from colorless body to colored body through irradiation is being promoted. This paper introduces the phenoxazine-based color former of solution type using the color former that changes color to blue through irradiation. The authors examined two types of phenoxazine-based color formers protected with alkyl oxycarbonyl group (-COOR), and mono-alkyl carbamoyl group (CONHR). Phenoxazine-based color former in acetonitrile solvent was revealed to be able to visually confirm the gamma irradiation dose of 10 Gy, but there is a problem of low temporal stability of the solution. (A.O.)

  17. The origin of the diffuse background gamma radiation

    Science.gov (United States)

    Stecker, F. W.; Puget, J. L.

    1974-01-01

    Recent observations provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV, and evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation were observed which provide evidence for its origin in nuclear processes in the early stages of big-bang cosmology, and connect these processes with the galaxy formation theory. A test of the theory is in future observations of the background radiation in the 100 MeK to 100 GeV energy range which are made with large orbiting spark-chamber satellite detectors. The theoretical interpretations of present data, their connection with baryon-symmetric cosmology and galaxy formation theory, and the need for future observations are discussed.

  18. The origin of the diffuse background gamma-radiation

    Science.gov (United States)

    Stecker, F. W.; Puget, J. L.

    1974-01-01

    Recent observations have now provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV. There is some evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation have been observed which provide evidence for its origin in nuclear processes in the early stages of the big-band cosmology and tie in these processes with galaxy fromation theory. A crucial test of the theory may lie in future observations of the background radiation in the 100 MeV to 100 GeV energy range which may be made with large orbiting spark-chamber satellite detectors. A discussion of the theoretical interpretations of present data, their connection with baryon symmetric cosmology and galaxy formation theory, and the need for future observations are given.

  19. Measurement of radioactivity in an elevated radiation background area of Western Ghats

    Directory of Open Access Journals (Sweden)

    Manigandan P.K.

    2014-01-01

    Full Text Available As part of monitoring the exposure of the general public to natural radioactivity, the activity concentration of naturally occurring radionuclides in soil samples in an elevated radiation background area of Western Ghats was determined using gamma-ray spectrometry. Average values of the activity concentration of radionuclides, outdoor terrestrial gamma dose rate, annual effective dose equivalent and radiation hazard indices from soil activity were estimated. The activity concentrations of 232Th and average outdoor terrestrial gamma dose rate were found to be higher than the world average, possibly affecting the Western Ghats environment in general. Therefore, radiological risks to the general population from ionizing radiation from the naturally occurring radionuclides in the soil are considered to be significant. How- ever, other radiological hazard indices were found to be within permissible limits.

  20. PRDC - A software package for personnel radiation dose calculation

    International Nuclear Information System (INIS)

    To determine effective dose, we usually need to use a very complicated human body model and a sophisticated computer code to transport radiations in the body model and surrounding medium, which is not very easy to practicing health physicists in the field. This study develops and tests a software package, called PRDC (Personnel Radiation Dose Calculation), which calculates effective dose and radiation doses to various organs/tissues and personal dosemeters based on a series of interpolations. (authors)

  1. Solid tumor risks after high doses of ionizing radiation

    OpenAIRE

    Sachs, Rainer K; Brenner, David J.

    2005-01-01

    There is increasing concern regarding radiation-related second-cancer risks in long-term radiotherapy survivors and a corresponding need to be able to predict cancer risks at high radiation doses. Although cancer risks at moderately low radiation doses are reasonably understood from atomic bomb survivor studies, there is much more uncertainty at the high doses used in radiotherapy. It has generally been assumed that cancer induction decreases rapidly at high doses due to cell killing. However...

  2. Design of radiation dose tumor response assays

    International Nuclear Information System (INIS)

    The efficient utilization of animals in a radiation dose response assay for tumor control requires a definition of the goal, e.g., TCD50 or slope. A series of computer modelled ''experiments'' have been performed for each of a number of allocations of dose levels (DL) and number of animals/DL. The authors stipulated that the assumed TCD50 was .85 of true value; assumed slope was correct. They stipulated a binominal distribution of observed tumor control results at each dose level. A pilot assay used 6 tumors at 7 DL (from TCD1-TCD97). The second assay used 30 tumors assigned to 2,3,5 or 9 DL and to selected tumor control probabilities (TCP derived from the pilot run. Results from 100 test runs were combined with the pilot run for each of the combination of DL and TCP values. Logit regression lines were fitted through these ''data'' and the 95% CL around the TCD50 and the TCD37 values and the variances of the slopes were computed. These experiments were repeated using the method suggested by Porter (1980). Results show that a different strategy is needed depending upon the goal, viz. TCD50 or TCD37 vs slope. The differences between the two approaches are discussed

  3. 广东高本底地区人群氧化损伤及抗氧化水平调查%The effects of low dose radiation on the levels of oxidative damage and antioxidant in population of high background radiation area of Guangdong

    Institute of Scientific and Technical Information of China (English)

    陈慧峰; 郭强之; 刘明; 耿继武; 苏世标

    2015-01-01

    目的 探讨长期连续天然放射性照射对人群氧化损伤及抗氧化水平的影响.方法 选择广东天然放射性高本底辐射地区(HBRA)48名男性居民为研究对象,选择恩平市某镇(CA)相匹配的48名男性居民为对照人群.采集2组人群外周静脉血并分离血浆,采用酶联免疫吸附试验(ELISA),测定血浆中DNA氧化损伤指标8-羟基脱氧鸟苷(8-OHdG)和抗氧化指标硫氧还蛋白还原酶(TrxR)的表达水平.结果 与对照组相比,高本底地区人群外周血血浆中DNA氧化损伤指标8-OHdG表达水平由(315.39±100.59) ng/ml降低至(272.64±96.85) ng/ml,抗氧化指标TrxR表达水平由(0.467±0.056) ng/ml升高至(0.496±0.044) ng/ml,两组间的差异均有统计学意义(t=2.121、-2.823,P<0.05).多元线性回归分析结果显示,在排除年龄、饮酒、喝茶、吸烟、接受医疗照射、生活应激事件等混杂因素的影响后,低剂量电离辐射个人累积剂量对8-OHdG和TrxR表达水平均有影响(t=-2.327、2.367,P<0.05).结论 长期接触低剂量电离辐射可降低人群氧化损伤水平,增强机体抗氧化水平.%Objective To investigate the effects of low dose radiation on the level of oxidative damage and antioxidant in population of high background radiation area of Guangdong.Methods A total of 48 male residents who lived in high background radiation area(HBRA) of Guangdong province and 48 male residents who lived in neighboring Enping control area were chosen as the objectives and control respectively.The peripheral venous blood of two groups was collected,and then the levels of 8-OHdG and TrxR were determined by enzyme linked immunosorbent assay (ELISA).Results Compared with the CA group [(315.39 ± 100.59) ng/ml],the level of 8-OHdG [(272.64 ± 96.85) ng/ml] decreased significantly in HBRA (t =2.121,P <0.05).Compared with the CA group [(0.467 ±0.056) ng/ml],the level of TrxR [(0.496 ± 0.044) ng/ml] increased significantly in HBRA (t =-2.823,P

  4. Scalar Radiation in the Background of a Naked Singularity

    CERN Document Server

    Dey, Anshuman; Sarkar, Tapobrata

    2013-01-01

    We study scalar radiation spectra from a particle in circular orbit, in the background of the Janis-Newman-Winicour (JNW) naked singularity. The differences in the nature of the spectra, from what one obtains with a Schwarzschild black hole, is established. We also compute the angular distribution of the spectra.

  5. Effects of Low Dose Radiation on Mammals 1

    OpenAIRE

    Okumura, Yutaka; Mine, Mariko; Kishikawa, Masao

    1991-01-01

    Radiation has been applied widely to clinics, researches and industries nowadays. Irradiation by atomic bomb produced many victims in Hiroshima and Nagasaki. Radiation effects on animals and human belings have been reported extensively, especially at a dose range of high amount of radiation. As radiation effects at low dose have not been well studied, it is believed that even a small amount of radiation produces hazardous effects. However, it might not be true. Beneficial effects of a low dos...

  6. Radiation doses inside industrial irradiation installation with linear electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alexandre R., E-mail: alexandre.lima@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Pelegrineli, Samuel Q.; Alo, Gabriel F., E-mail: samuelfisica@yahoo.com.br, E-mail: gabriel.alo@aceletron.com.br [Aceletron Irradiacao Industrial, Aceletrica Comercio e Representacoes Ltda, Rio de Janeiro, RJ (Brazil); Silva, Francisco C.A. Da, E-mail: dasilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Aceletron Industrial Irradiation Company is the unique installation in South America to provide industrial irradiation service using two linear electron accelerators of 18 kW and 10 MeV energy. The electron beam technology allows using electrons to irradiate many goods and materials, such as hospital and medical equipment, cosmetics, herbal products, polymers, peat, gemstones and food. Aceletron Company uses a concrete bunker with 3.66 m of thickness to provide the necessary occupational and environmental radiation protection of X-rays produced. The bunker is divided in main four areas: irradiation room, maze, tower and pit. Inside the irradiation room the x-rays radiation rates are measured in two ways: direct beam and 90 deg C. The rates produced in the conveyor system using 10 MeV energy are 500 Gy/min/mA and 15 Gy/min/mA, respectively. For a 1.8 mA current, the rates produced are 900 Gy/min and 27 Gy/min, respectively. Outside the bunker the radiation rate is at background level, but in the tower door and modulation room the radiation rate is 10 μSv/h. In 2014, during a routine operation, an effective dose of 30.90 mSv was recorded in a monthly individual dosimeter. After the investigation, it was concluded that the dose was only in the dosimeter because it felt inside the irradiation room. As Aceletron Company follows the principles of safety culture, it was decided to perform the radiation isodose curves, inside the four areas of the installation, to know exactly the hotspots positions, exposure times and radiation doses. Five hotspots were chosen taking into account worker's routes and possible operational places. The first experiment was done using a package with three TLD and OSLD dosimeters to obtain better statistical results. The first results for the five hotspots near the accelerator machine showed that the radiation dose rates were between 26 Gy/h and 31 Gy/h. The final measurements were performed using a package with one TLD and one OSLD

  7. Background Radiation Measurements at High Power Research Reactors

    CERN Document Server

    Ashenfelter, J; Baldenegro, C X; Band, H R; Barclay, G; Bass, C D; Berish, D; Bowden, N S; Bryan, C D; Cherwinka, J J; Chu, R; Classen, T; Davee, D; Dean, D; Deichert, G; Dolinski, M J; Dolph, J; Dwyer, D A; Fan, S; Gaison, J K; Galindo-Uribarri, A; Gilje, K; Glenn, A; Green, M; Han, K; Hans, S; Heeger, K M; Heffron, B; Jaffe, D E; Kettell, S; Langford, T J; Littlejohn, B R; Martinez, D; McKeown, R D; Morrell, S; Mueller, P E; Mumm, H P; Napolitano, J; Norcini, D; Pushin, D; Romero, E; Rosero, R; Saldana, L; Seilhan, B S; Sharma, R; Stemen, N T; Surukuchi, P T; Thompson, S J; Varner, R L; Wang, W; Watson, S M; White, B; White, C; Wilhelmi, J; Williams, C; Wise, T; Yao, H; Yeh, M; Yen, Y -R; Zhang, C; Zhang, X

    2016-01-01

    Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including $\\gamma$-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. The general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.

  8. Search for radiative decays of cosmic background neutrino using cosmic infrared background energy spectrum

    International Nuclear Information System (INIS)

    We propose to search for the neutrino radiative decay by fitting a photon energy spectrum of the cosmic infrared background to a sum of the photon energy spectrum from the neutrino radiative decay and a continuum. By comparing the present cosmic infrared background energy spectrum observed by AKARI and Spitzer to the photon energy spectrum expected from neutrino radiative decay with a maximum likelihood method, we obtained a lifetime lower limit of 3.1x1012 to 3.8x1012 years at 95% confidence level for the third generation neutrino v3 in the v3 mass range between 50 and 150 meV/c2 under the present constraints by the neutrino oscillation measurements. In the left-right symmetric model, the minimum lifetime of v3 is predicted to be 1.5x1017 years for m3 of 50 meV/c2. We studied the feasibility of the observation of the neutrino radiative decay with a lifetime of 1.5x1017 years, by measuring a continuous energy spectrum of the cosmic infrared background. (author)

  9. Suppressing Background Radiation Using Poisson Principal Component Analysis

    CERN Document Server

    Tandon, P; Dubrawski, A; Labov, S; Nelson, K

    2016-01-01

    Performance of nuclear threat detection systems based on gamma-ray spectrometry often strongly depends on the ability to identify the part of measured signal that can be attributed to background radiation. We have successfully applied a method based on Principal Component Analysis (PCA) to obtain a compact null-space model of background spectra using PCA projection residuals to derive a source detection score. We have shown the method's utility in a threat detection system using mobile spectrometers in urban scenes (Tandon et al 2012). While it is commonly assumed that measured photon counts follow a Poisson process, standard PCA makes a Gaussian assumption about the data distribution, which may be a poor approximation when photon counts are low. This paper studies whether and in what conditions PCA with a Poisson-based loss function (Poisson PCA) can outperform standard Gaussian PCA in modeling background radiation to enable more sensitive and specific nuclear threat detection.

  10. Alternative application for the radiation background in the development of the atlas database of atmospheric radiation

    CERN Document Server

    De la Hoz, Ivan Arturo Morales

    2014-01-01

    Nowadays radiation is one of the variables to be considered in the environmental forecasting and it is meaningful in the increase of global warming, together greenhouse effect. The radiation considered by the meteorological organizations depends on the World Radiometric Reference (WRR), the World Standard Group (WSG), addressed by the World Meteorological Organization (WMO). This work is based on the cosmic microwave background, as a variable to be estimated in order to get information about the incident radiation in the Earth's atmosphere, as a valuable and meaningful contribution in the building of the radiation atlas by the (UPME) and (IDEAM). Due to the fact that the variables considered are ultraviolet and infrared radiation, ozone column, direct radiation and diffuse radiation, the last two get the global radiation, and are the only ones to be evaluated by the national meteorological organizations in the country. The study of the cosmic background radiation as a research project will provide data which ...

  11. The Cosmic Microwave Background Radiation and its Polarization

    Science.gov (United States)

    Wollack, Edward

    2016-03-01

    The cosmic microwave background (CMB) radiation and its faint polarization have provided a unique means to constrain the physical state of the early Universe. Continued advances in instrumentation, observation, and analysis have revealed polarized radiation signatures associated with gravitational lensing and have heightened the prospects for using precision polarimetry to experimentally confront the inflationary paradigm. Characterization of this relic radiation field has the power to constrain or reveal the detailed properties of astroparticle species and long wave gravitational radiation. On going and planned CMB polarization efforts from the ground, balloon, and space borne platforms will be briefly surveyed. Recent community activities by the Inflation Probe Science Interest Group (IPSIG) will also be summarized. NASA PCOS mini-symposium (invited IPSIG talk).

  12. Radiative feedback from an early X-ray background

    CERN Document Server

    Glover, S C O; Glover, Simon C.O.; Brand, Peter W.J.L.

    2003-01-01

    The first generation of stars (commonly known as population III) are expected to form in low-mass protogalaxies in which molecular hydrogen is the dominant coolant. Radiation from these stars will rapidly build up an extragalactic ultraviolet background capable of photodissociating H2, and it is widely believed that this background will suppress further star formation in low-mass systems. However, star formation will also produce an extragalactic X-ray background. This X-ray background, by increasing the fractional ionization of protogalactic gas, promotes H2 formation and reduces the effectiveness of ultraviolet feedback. In this paper, we examine which of these backgrounds has the dominant effect. Using a simple model for the growth of the UV and X-ray backgrounds, together with a detailed one-dimensional model of protogalactic chemical evolution, we examine the effects of the X-ray backgrounds produced by a number of likely source models. We show that in several cases, the resulting X-ray background is str...

  13. Direct determination of internal radiation dose in human blood

    CERN Document Server

    Tanır, Ayse Güneş

    2014-01-01

    The purpose of this study is to measure the internal radiation dose using a human blood sample. In the literature, there is no process that allows the direct measurement of the internal radiation dose received by a person. The luminescence counts from a blood sample having a laboratory-injected radiation dose and the waste blood of the patient injected with a radiopharmaceutical for diagnostic purposes were both measured. The decay and dose-response curves were plotted for the different doses. The doses received by the different blood aliquots can be determined by interpolating the luminescence counts to the dose-response curve. This study shows that the dose received by a person can be measured directly, simply and retrospectively by using only a very small amount of blood sample. The results will have important ramifications for the medicine and healthcare fields in particular. This will also be very important in cases of suspicion of radiation poisoning, malpractice and so on.

  14. External radiation survey and dose predictions for Rongelap, Utirik, Rongerik, Ailuk, and Wotje Atolls

    International Nuclear Information System (INIS)

    External radiation measurements were made at several atolls in the northern Marshall Islands, which are known or suspected to have been the recipients of tropospheric fallout during the Pacific Testing Programs. Sufficient data were available to ascertain realistic dose predictions for the inhabitants of Rongelap and Utirik Atolls where the 30 year integral doses from external sources exclusive of background radiation were 0.65 and 0.06 rem respectively. These estimates are based on realistic life-style models based on observations of each atoll community. Ailuk and Wotje Atolls were found to be represenatives of regional background radiation levels

  15. Current issues in carcinogenic effect of low-dose radiation

    International Nuclear Information System (INIS)

    A review of publications dealing with study of radiation sources and biological evaluation of increasing doses of people irradiation under occupational and usual living conditions is presented. The existing natural and artifial irradiation sources are considered. It is noted that all types of ionizing radiations are characterized by high carcinogenic efficiency and can induce benign and malignant tumors practically in all organs. Statistically reliable data in experimental and epidemiological investigations were recorded under the effect of large and mean doses. Minor radiation doses not responsible for visible functional and morphological changes in early periods can cause pathological changes in delayed periods. The data on carcinogenic effect of relatively small radiation doses are available

  16. Public exposure due to external gamma background radiation in boundary areas of Iran.

    Science.gov (United States)

    Pooya, S M Hosseini; Dashtipour, M R; Enferadi, A; Orouji, T

    2015-09-01

    A monitoring program in boundary areas of a country is an appropriate way to indicate the level of public exposure. In this research, gamma background radiation was measured using TL dosimeters at 12 boundary areas as well as in the capital city of Iran during the period 2010 to 2011. The measurements were carried out in semi-annual time intervals from January to June and July to December in each year. The maximum average dose equivalent value measured was approximately 70 μSv/month for Tehran city. Also, the average dose values obtained were less than 40 μSv/month for all the cities located at the sea level except that of high level natural radiation area of Ramsar, and more than 55 μSv/month for the higher elevation cities. The public exposure due to ambient gamma dose equivalent in Iran is within the levels reported by UNSCEAR. PMID:26057985

  17. Wormhole solution of BD theory in an anisotropic radiation background

    Directory of Open Access Journals (Sweden)

    B. Nasre Esfahani

    2001-06-01

    Full Text Available   Time-dependent wormhole solution of the BD theory in an anisotropic radiation background is presented. It is also found that the BD scalar field depends only on time. This time dependency is in power-law form. It is shown that the wormhole geometry is valid for ω ≥ -3/2, and for any arbitrary positive values of . The GR limit of our solution is obtained for ω=0 , not for ω→∞ . Though the BD field can be non-exotic, the background material is entirely exotic.

  18. Nature of the Background Ultraviolet Radiation Field at High Redshifts

    Indian Academy of Sciences (India)

    Archana Samantaray; Pushpa Khare

    2000-06-01

    We have tried to determine the flux of the ultraviolet background radiation field from the column density ratios of various ions in several absorption systems observed in the spectra of QSOs. We find that in most cases the flux is considerably higher than what has been estimated to be contributed by the AGNs. The excess flux could originate locally in hot stars. In a few cases we have been able to show that such galactic flux can only contribute a part of the total required flux. The results suggest that the background gets a significant contribution from an unseen QSO population.

  19. Study of Natural Background Radiation around Gurvanbulag Uranium Deposit Area

    Science.gov (United States)

    Enkhbat, N.; Norov, N.; Bat-Erdene, B.; Khuukhenkhuu, G.; Otgooloi, B.

    2009-03-01

    In this work, we will show the study of natural background radiation level around the Gurvanbulag (GB) uranium deposit area in the eastern part of Mongolia. We collected environmental soil samples from 102 points around GB Uranium deposit. Collected samples were measured by HPGe gamma spectrometer at Nuclear Research Center, National University of Mongolia. The averaged activity concentrations of Ra-226, Th-232, K-40, and Cs-137 were 37.1, 29, 939, and 17.7 Bq/kg, respectively.

  20. Backgrounds of computer-assisted treatment planning in radiation therapy

    International Nuclear Information System (INIS)

    Interaction of ionising radiation and living materials causes biological damage of tempory or permanent nature. In radiation therapy this phenomenon is used in a controlled fashion in order to stop the proliferation of malignant cells, while at the same time limiting the permanent damage to healthy tissues and organs to at least tolerable levels. Because of the often relatively small differences in response of malignant growths and normal tissues, the margins between tolerable and intolerable are so small that the greatest precision in treatment planning and execution is required. The nature of this treatment agent implies that the radiation therapist has to rely very much on instrumentally obtained and processed information, in all phases of this medical activities around the patient. In this paper a description is given of the backgrounds of computer-assisted methods which have enabled modern individualised and optimised planning for therapy with high energy X- and gamma beams. (orig.)

  1. Individual monitoring of external radiation - dose quantities and their relevance to radiation protection

    International Nuclear Information System (INIS)

    External exposures due to the use of ionising radiation are the major contributor to doses to radiation workers. X-and gamma rays from radiation sources and radiation generating equipment's from the main component of dose. This is because of their penetrating power and wider abundance due to their use in medical, industrial research and agriculture fields. Although in some cases, beta radiation and neutrons also form some significant component to dose, their overall contribution remains much lower

  2. CERN-derived analysis of lunar radiation backgrounds

    Science.gov (United States)

    Wilson, Thomas L.; Svoboda, Robert

    1993-01-01

    The Moon produces radiation which background-limits scientific experiments there. Early analyses of these backgrounds have either failed to take into consideration the effect of charm in particle physics (because they pre-dated its discovery), or have used branching ratios which are no longer strictly valid (due to new accelerator data). We are presently investigating an analytical program for deriving muon and neutrino spectra generated by the Moon, converting an existing CERN computer program known as GEANT which does the same for the Earth. In so doing, this will (1) determine an accurate prompt neutrino spectrum produced by the lunar surface; (2) determine the lunar subsurface particle flux; (3) determine the consequence of charm production physics upon the lunar background radiation environment; and (4) provide an analytical tool for the NASA astrophysics community with which to begin an assessment of the Moon as a scientific laboratory versus its particle radiation environment. This will be done on a recurring basis with the latest experimental results of the particle data groups at Earth-based high-energy accelerators, in particular with the latest branching ratios for charmed meson decay. This will be accomplished for the first time as a full 3-dimensional simulation.

  3. Radiation Dose Risk and Diagnostic Benefit in Imaging Investigations

    CERN Document Server

    Dobrescu, Lidia

    2015-01-01

    The paper presents many facets of medical imaging investigations radiological risks. The total volume of prescribed medical investigations proves a serious lack in monitoring and tracking of the cumulative radiation doses in many health services. Modern radiological investigations equipment is continuously reducing the total dose of radiation due to improved technologies, so a decrease in per caput dose can be noticed, but the increasing number of investigations has determined a net increase of the annual collective dose. High doses of radiation are cumulated from Computed Tomography investigations. An integrated system for radiation safety of the patients investigated by radiological imaging methods, based on smart cards and Public Key Infrastructure allow radiation absorbed dose data storage.

  4. A survey of senile dementia in the high background radiation areas in Yangjiang, China

    International Nuclear Information System (INIS)

    Objective: To evaluate the effects of long-term low dose and low dose-rate ionizing radiation exposure on the prevalence rate of senile dementia, further assess the effects of low-dose radiation exposure on central nervous system and study the pathogen of senile dementia, and provide direct observational data of human beings. Methods: A cross-sectional study of the prevalence of senile dementia was carried out in high background radiation areas in Yangjiang, Guangdong Province, China. The survey was conducted in two stages. For the initial screening, Hasegawa Dementia Scale (HDS) was used for all subjects. In the second stage, the stage of diagnosis, special questionnaires of healthy state of old people were sued. The final diagnoses were made according to the third revised edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM III-R) of American Psychiatric Association. Results: 1018 inhabitants aged 65 years and over, including 513 persons in HBRA and 505 in CA were observed. According to DSM III-R, 61 cases (31 cases in HBRA and 30 cases in CA) of senile dementia were diagnosed. The prevalence rates of senile dementia are 6.04% in HBRA and 5.94% in CA, the total prevalence rate being 5.99%. Conclusion: No significant statistical difference in the prevalence rate of senile dementia between the two areas was found, suggesting that the prevalence rate of senile dementia in these areas is not associated with the high background radiation exposure

  5. Radiation doses from contaminant aerosol deposition to the human body

    International Nuclear Information System (INIS)

    Nearly all assessments of radiation doses received following accidental airborne releases have focused on the contributions originating from the plume and from ground deposition. Very little thought has however been given to doses received from deposition directly onto humans. The results of recent experimental investigations of aerosol deposition to and clearance from human skin and clothing have been used to model the doses potentially received in an accident situation. It was found that both the skin dose from β-emitters and the whole body dose from γ-emitters may be significant compared with doses received through other pathways, such as external radiation from the environment. (au)

  6. Knowledge of medical imaging radiation dose and risk among doctors

    International Nuclear Information System (INIS)

    The growth of computed tomography (CT) and nuclear medicine (NM) scans has revolutionised healthcare but also greatly increased population radiation doses. Overuse of diagnostic radiation is becoming a feature of medical practice, leading to possible unnecessary radiation exposures and lifetime-risks of developing cancer. Doctors across all medical specialties and experience levels were surveyed to determine their knowledge of radiation doses and potential risks associated with some diagnostic imaging. A survey relating to knowledge and understanding of medical imaging radiation was distributed to doctors at 14 major Queensland public hospitals, as well as fellows and trainees in radiology, emergency medicine and general practice. From 608 valid responses, only 17.3% correctly estimated the radiation dose from CT scans and almost 1 in 10 incorrectly believed that CT radiation is not associated with any increased lifetime risk of developing cancer. There is a strong inverse relationship between a clinician's experience and their knowledge of CT radiation dose and risks, even among radiologists. More than a third (35.7%) of doctors incorrectly believed that typical NM imaging either does not use ionising radiation or emits doses equal to or less than a standard chest radiograph. Knowledge of CT and NM radiation doses is poor across all specialties, and there is a significant inverse relationship between experience and awareness of CT dose and risk. Despite having a poor understanding of these concepts, most doctors claim to consider them prior to requesting scans and when discussing potential risks with patients.

  7. Vertebrate radiations of the Jehol Biota and their environmental background

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhonghe

    2004-01-01

    @@ Significant progress has been made in recent years in the studies of various groups of the Jehol Biota, particularly concerning the origin of birds and their flight as well as the evolution of Early Cretaceous birds, dinosaurs, mammals, insects and flowering plants[1-5]. As a result, the Jehol Biota has become well known to both the scientific community and the public. The studies on the Jehol Biota also revealed the patterns and processes of the evolutionary radiations of many major groups of Early Cretaceous animals and plants, such as the earliest known radiation of angiosperms and birds, early differentiation of mammals and many Cretaceous dinosaurian groups. Notably, the radiations of the Jehol vertebrates share some similar patterns attributable to the particular environmental background. For instance, the Jehol vertebrate radiations are highlighted by the presence of abundant arboreal adaptations and herbivorous forms, thus closely linked to the forest environments. In addition, the differentiation of habitats and diets is also characteristic of the evolutionary radiations of pterosaurs, dinosaurs, birds and mammals in the Jehol Biota.

  8. Mortality from diseases other than cancer following low doses of ionizing radiation

    DEFF Research Database (Denmark)

    Vrijheid, M; Cardis, E; Ashmore, P;

    2007-01-01

    BACKGROUND: Ionizing radiation at very high (radio-therapeutic) dose levels can cause diseases other than cancer, particularly heart diseases. There is increasing evidence that doses of the order of a few sievert (Sv) may also increase the risk of non-cancer diseases. It is not known, however......, whether such effects also occur following the lower doses and dose rates of public health concern. METHODS: We used data from an international (15-country) nuclear workers cohort study to evaluate whether mortality from diseases other than cancer is related to low doses of external ionizing radiation....... Analyses included 275 312 workers with adequate information on socioeconomic status, over 4 million person-years of follow-up and an average cumulative radiation dose of 20.7 mSv; 11 255 workers had died of non-cancer diseases. RESULTS: The excess relative risk (ERR) per Sv was 0.24 [95% CI (confidence...

  9. Assessment of background gamma radiation and determination of excess lifetime cancer risk in Sabzevar City, Iran in 2014

    Directory of Open Access Journals (Sweden)

    Akbar Eslami

    2016-01-01

    Full Text Available Background: Background gamma radiation levels vary in different locations and depended on many factors such as radiation properties of soil, building materials as well as construction types which human lives on it. People are always exposed to ionizing radiation, which could badly influence their health. The aim of this study was to evaluate the background gamma-ray dose rate and the estimated annual effective dose equivalent and determination of excess lifetime cancer risk in Sabzevar City, Iran. Methods: The aim of this cross-sectional study was to determine the dose rate of background gamma radiation in outdoor an indoor areas, 26 stations were selected using the map of the Sabzevar City. The amount of gamma radiation was measured at 4 months (September to January in 2014 year. The dosimeter used in this study was a survey meter, that is designed for monitoring radiation of x, gamma and beta rays. Results: The obtained results show that there are significant differences between the indoor and outdoor exposures (P> 0.05. We did not observe significant differences between the time of sampling and sampling locations, (P<0.05. The minimum and maximum values of dose rate were found 66±20 nSvh-1 and 198±28 nSvh-1. The annual effective dose for Sabzevar residents was estimated to be 0.85 mSv and also the amount of excess lifetime cancer risk was estimated 3.39×10-3. Conclusion: According to the results, the excess lifetime cancer risk and the annual effective dose for the Sabzavar City residents due to the background gamma radiation was higher than the global average (0.5 mSv. The epidemiological studies have been proposed to evaluate the risk of chronic diseases associated with natural radiation exposure among residents.

  10. Personal exposure to grass pollen: relating inhaled dose to background concentration

    DEFF Research Database (Denmark)

    Peel, Robert George; Hertel, Ole; Smith, Matt;

    2013-01-01

    . A 2003 World Health Organization report highlighted the need for an improved understanding of the relation between monitoring station data and actual exposure. Objective: To investigate the relation between grass pollen dose and background concentrations measured at a monitoring station, to assess...... the fidelity of monitoring station data as a qualitative proxy for dose, and to evaluate the ratio of dose rate to background concentration. Methods: Grass pollen dose data were collected in Aarhus, Denmark, in an area where grass pollen sources were prevalent, using Nasal Air Samplers. Sample collection...... of day when grass species likely to be present in the area are expected to flower. From 4 to 8 PM, dose rate and background concentration data were found to be strongly and significantly correlated (r(s) = 0.81). Averaged dose rate and background concentration data showed opposing temporal trends...

  11. Energies, health, medicine. Low radiation doses; Energies, sante, medecine. Les faibles doses de rayonnement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This file concerns the biological radiation effects with a special mention for low radiation doses. The situation of knowledge in this area and the mechanisms of carcinogenesis are detailed, the different directions of researches are given. The radiation doses coming from medical examinations are given and compared with natural radioactivity. It constitutes a state of the situation on ionizing radiations, known effects, levels, natural radioactivity and the case of radon, medicine with diagnosis and radiotherapy. (N.C.)

  12. The 1999 Lauriston S. Taylor lecture--back to background: natural radiation and radioactivity exposed.

    Science.gov (United States)

    Harley, N H

    2000-08-01

    I am profoundly grateful for being chosen as the twenty-third presenter of the Lauriston S. Taylor Lecture, and I share this honor with a list of distinguished scientists, including my husband, who pay tribute to the premier leader in radiation protection. In 1938, Laurie was working for the National Bureau of Standards and chaired the Advisory Committee on X-ray and Radium Protection, a group of 8 persons, who set the pace for all forthcoming radiation standards. NBS had, since 1913, been standardizing essentially all of the radium offered for sale in the U.S., and the problem arose to revise the handbook on proper conditions for handling radium based on the then current knowledge. This resulted in Handbook 23 (1938) superseding the 1934 work. At the time Laurie was a scientist working in the measurements side of radiation and though he contributed much to that field, his name is inseparably linked with guidance in radiation protection. Today we pay tribute for his leadership that he carried out with intelligence, grace, and personal warmth. My talk today deals mostly with measured data for naturally occurring internal radiation emitters and how these data can be used for predictive purposes in estimating the dose and risk from internal body contamination. This stresses the "and Measurements" part of the Council's title. The topic of this year's NCRP Annual Meeting is "Radiation Protection in Medicine: Contemporary Issues." I believe that physicians and State and Federal agencies will have to cope with complaints following various exposure situations resulting from the cleanup of background radionuclides during closure at nuclear facilities, military use of radioactivity, and occurrences of high natural background in some locations. They will find comfort in the knowledge that existing background radiation data can be the basis for predictions of realistic dose and risk in most situations. PMID:10910381

  13. Confounding factors in radiation epidemiology and their comparability between high background radiation areas and control areas in Yangjiang, China

    International Nuclear Information System (INIS)

    Objective: Confounding factors in radiation epidemiology and their comparability among the four different dose-rate groups in high background radiation areas were studied. Methods: The demography data were collected by a specific registration method. For the components of diet and life style, the samples were taken by a stratified random sampling method. Results: The sex-, age-distributions and the life expectancy of the members of a cohort 35 years old and above in the four dose-rate groups were similar to each other. The components of diet were constituted mostly of grains and vegetables with less meat, eggs and milk. The percentages of cigarette smokers were 27.7%-31.3% in both male and female subjects and the percentages of alcohol drinkers were 4.0%-6.9% in them. Conclusion: The results show that there is good comparability between the four dose-rate groups except for background radiation level, and it is suggested that the taken food consisting of grains and vegetables may be a beneficial factor leading to low incidence of malignancies in this area

  14. Measuring radiation dose to patients undergoing fluoroscopically-guided interventions

    Science.gov (United States)

    Lubis, L. E.; Badawy, M. K.

    2016-03-01

    The increasing prevalence and complexity of fluoroscopically guided interventions (FGI) raises concern regarding radiation dose to patients subjected to the procedure. Despite current evidence showing the risk to patients from the deterministic effects of radiation (e.g. skin burns), radiation induced injuries remain commonplace. This review aims to increase the awareness surrounding radiation dose measurement for patients undergoing FGI. A review of the literature was conducted alongside previous researches from the authors’ department. Studies pertaining to patient dose measurement, its formalism along with current advances and present challenges were reviewed. Current patient monitoring techniques (using available radiation dosimeters), as well as the inadequacy of accepting displayed dose as patient radiation dose is discussed. Furthermore, advances in real-time patient radiation dose estimation during FGI are considered. Patient dosimetry in FGI, particularly in real time, remains an ongoing challenge. The increasing occurrence and sophistication of these procedures calls for further advances in the field of patient radiation dose monitoring. Improved measuring techniques will aid clinicians in better predicting and managing radiation induced injury following FGI, thus improving patient care.

  15. The researches of medical and environmental radiation protection dose

    OpenAIRE

    盧, 暁光

    2013-01-01

    Nowadays, with the development of modern radiation science, application of radiation exposure has been paid more and more attention in various fields. Although there are many benefits for human by the use of radiation in such as medical diagnose and treatment, utilization of nuclear power, more efforts should be made to radiation hazards and their control that are often neglected. The researches in this study were intended to meet the requirements with the center of radiation protection dose ...

  16. Radiation dose distributions due to sudden ejection of cobalt device.

    Science.gov (United States)

    Abdelhady, Amr

    2016-09-01

    The evaluation of the radiation dose during accident in a nuclear reactor is of great concern from the viewpoint of safety. One of important accident must be analyzed and may be occurred in open pool type reactor is the rejection of cobalt device. The study is evaluating the dose rate levels resulting from upset withdrawal of co device especially the radiation dose received by the operator in the control room. Study of indirect radiation exposure to the environment due to skyshine effect is also taken into consideration in order to evaluate the radiation dose levels around the reactor during the ejection trip. Microshield, SHLDUTIL, and MCSky codes were used in this study to calculate the radiation dose profiles during cobalt device ejection trip inside and outside the reactor building. PMID:27423021

  17. Calculation of the dose caused by internal radiation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    For the purposes of monitoring radiation exposure it is necessary to determine or to estimate the dose caused by both external and internal radiation. When comparing the value of exposure to the dose limits, account must be taken of the total dose incurred from different sources. This guide explains how to calculate the committed effective dose caused by internal radiation and gives the conversion factors required for the calculation. Application of the maximum values for radiation exposure is dealt with in ST guide 7.2, which also sets out the definitions of the quantities and concepts most commonly used in the monitoring of radiation exposure. The monitoring of exposure and recording of doses are dealt with in ST Guides 7.1 and 7.4.

  18. Low dose radiation and plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Jae; Lee, Hae Youn; Park, Hong Sook

    2001-03-01

    Ionizing radiation includes cosmic radiation, earth radiation, radionuclides for the medical purpose and nuclear industry, fallout radiation. From the experimental results of various radiation effects on seeds or seedlings, it was found that germination rate, development, respiration rate, reproduction and blooming were accelerated compared with the control. In mammal, hormesis phenomenon manifested itself in increased disease resistance, lifespan, and decreased rate of tumor incidence. In plants, it was shown that germination, sprouting, growth, development, blooming and resistance to disease were accelerated.

  19. Low dose radiation and plant growth

    International Nuclear Information System (INIS)

    Ionizing radiation includes cosmic radiation, earth radiation, radionuclides for the medical purpose and nuclear industry, fallout radiation. From the experimental results of various radiation effects on seeds or seedlings, it was found that germination rate, development, respiration rate, reproduction and blooming were accelerated compared with the control. In mammal, hormesis phenomenon manifested itself in increased disease resistance, lifespan, and decreased rate of tumor incidence. In plants, it was shown that germination, sprouting, growth, development, blooming and resistance to disease were accelerated

  20. A Bayesian Semiparametric Model for Radiation Dose-Response Estimation.

    Science.gov (United States)

    Furukawa, Kyoji; Misumi, Munechika; Cologne, John B; Cullings, Harry M

    2016-06-01

    In evaluating the risk of exposure to health hazards, characterizing the dose-response relationship and estimating acceptable exposure levels are the primary goals. In analyses of health risks associated with exposure to ionizing radiation, while there is a clear agreement that moderate to high radiation doses cause harmful effects in humans, little has been known about the possible biological effects at low doses, for example, below 0.1 Gy, which is the dose range relevant to most radiation exposures of concern today. A conventional approach to radiation dose-response estimation based on simple parametric forms, such as the linear nonthreshold model, can be misleading in evaluating the risk and, in particular, its uncertainty at low doses. As an alternative approach, we consider a Bayesian semiparametric model that has a connected piece-wise-linear dose-response function with prior distributions having an autoregressive structure among the random slope coefficients defined over closely spaced dose categories. With a simulation study and application to analysis of cancer incidence data among Japanese atomic bomb survivors, we show that this approach can produce smooth and flexible dose-response estimation while reasonably handling the risk uncertainty at low doses and elsewhere. With relatively few assumptions and modeling options to be made by the analyst, the method can be particularly useful in assessing risks associated with low-dose radiation exposures. PMID:26581473

  1. Radiation dose rates from UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Friend, P.J. [Urenco, Capenhurst (United Kingdom)

    1991-12-31

    This paper describes the results of many studies, both theoretical and experimental, which have been carried out by Urenco over the last 15 years into radiation dose rates from uranium hexafluoride (UF{sub 6}) cylinders. The contents of the cylinder, its history, and the geometry all affect the radiation dose rate. These factors are all examined in detail. Actual and predicted dose rates are compared with levels permitted by IAEA transport regulations.

  2. Cosmic Rays Induced Background Radiation on Board of Commercial Flights

    CERN Document Server

    Pinilla, S; Núñez, L A

    2015-01-01

    The aim of this work is to determine the total integrated flux of cosmic radiation which a commercial aircraft is exposed to along specific flight trajectories. To study the radiation background during a flight and its modulation by effects such as altitude, latitude, exposure time and transient magnetospheric events, we perform simulations based on Magnetocosmics and CORSIKA codes, the former designed to calculate the geomagnetic effects on cosmic rays propagation and the latter allows us to simulate the development of extended air showers in the atmosphere. In this first work, by considering the total flux of cosmic rays from 5 GeV to 1 PeV, we obtained the expected integrated flux of secondary particles on board of a commercial airplane during the Bogot\\'a-Buenos Aires trip by point-to-point numerical integration.

  3. Radionuclides and radiation indices of high background radiation area in Chavara-Neendakara placer deposits (Kerala, India.

    Directory of Open Access Journals (Sweden)

    Mary Thomas Derin

    Full Text Available The present paper describes a detailed study on the distribution of radionuclides along Chavara - Neendakara placer deposit, a high background radiation area (HBRA along the Southwest coast of India (Kerala. Judged from our studies using HPGe gamma spectrometric detector, it becomes evident that Uranium ((238U, Thorium ((232Th and Potassium ((40K are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation between (238U and (232Th, implicating that the levels of these elements are interdependent. Our SEM-EDAX analyses reveal that titanium (Ti and zircon (Zr are the major trace elements in the sand samples, followed by aluminum, copper, iron, ruthenium, magnesium, calcium, sulphur and lead. This is first of its kind report on the radiation hazard indices on this placer deposit. The average absorbed dose rates (9795 nGy h(-1 computed from the present study is comparable with the top-ranking HBRAs in the world, thus offering the Chavara-Neendakara placer the second position, after Brazil; pertinently, this value is much higher than the World average. The perceptibly high absorbed gamma dose rates, entrained with the high annual external effective dose rates (AEED and average annual gonadal dose equivalent (AGDE values existing in this HBRA, encourage us to suggest for a candid assessment of the impact of the background radiation, if any, on the organisms that inhabit along this placer deposit. Future research could effectively address the issue of the possible impact of natural radiation on the biota inhabiting this HBRA.

  4. Radiation dose estimates for copper-64 citrate in man

    International Nuclear Information System (INIS)

    Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. The authors have performed studies with animal-tumor-bearing models that have demonstrated the rapid uptake of copper-64. The radiation dose estimates for man indicate that the intravenous administration of 7.0 mCi would result in radiation doses to the kidney of 9.8 to 10.5 rads with other organs receiving substantially less radiations. 5 references, 3 tables

  5. How to understand the radiation effects of small dose - some critical comments on ICRP recommendations

    International Nuclear Information System (INIS)

    The widespread feeling of 'radiophobia' by the general public has its basis on the ICRP's 'linear no-threshold' hypothesis in dose-response relationship for low dose radiation from the standpoint of radiation protection. Although this common feeling served as a merit for constructing the 'safety culture' of society, it has now become a large obstacle for the development of peaceful uses of nuclear technology as a demerit. Recently many data have been accumulated for the radiation effects of low dose, both epidemiologically and experimentally. Although in general it is very difficult to obtain clear evidence of presence or absence of threshold, it seems to be true that the risk by radiation exposure at low level (the definition of which is below 0.2 Gy) is not so large as that of extrapolation from the high or medium dose range. In fact, many data suggest that some quite different mechanisms are working in low dose from high dose, such as 'adaptive response', and a new concept, 'radiation hormesis', has emerged, that the low level radiation is not only quite harmless but is rather necessary for living cells or beneficial for human health. In this paper, some critical comments on ICRP recommendations are given as a personal view by the author. These include: (1) a question of exact assessment of exposed dose by A-bomb survivors used for the epidemiological data, which are regarded to be the most authentic and important; (2) a brief summary of effects at the natural radiation level, including the high background area data; (3) the importance of dose rate effect, which reflects the living matter's repairability from radiation injury, and (4) the proposal of new paradigm by adopting the reasonable 'de minimis' level (below which there is no harm) both for low dose and at low dose rate. A simple mathematical analysis for representative data of dose rate effect was shown as an appendix

  6. Reduction of the radiation dose received by interventional cardiologists following training in radiation protection

    International Nuclear Information System (INIS)

    The University General Hospital of Alexandroupolis was established in 2003 to cover Eastern Macedonia and Thrace Districts of Northern Greece. The hospital has two interventional cardiology units and the occupational radiation exposure of the cardiologists was the highest of all specialties using ionising radiation. In order to aid in decreasing the radiation dose levels, a seminar was organised for all personnel working in interventional radiology field. After this, an important reduction of the radiation dose of the cardiologists was noted. Training in radiation protection is essential to reduce the radiation doses and consequently the deterministic and stochastic effects of ionising radiation of cardiologists working in interventional radiology. (authors)

  7. Long-term radiation dose reduction plan of KHNP

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Saeng-Ki; Shin, Sang-Woon; Lim, Byoung-Chan [Korea Hydro and Nuclear Power Company, Seoul (Korea, Republic of)

    2002-07-01

    Annual radiation dose limit to radiation worker was substantially lowered in Korea by the adoption of 1990 recommendations of the International Commission on Radiation Protection (ICRP 60) in its legislation. On the other hand, radiation management environment in nuclear power plants is getting more worse because of the accumulation of radiation sources inside the system and the frequent need for maintenance according as the operation years of nuclear power plants increase. Therefore, Korea Hydro and Nuclear power Co., Ltd. (KHNP) has established a long-term 10 years' plan from 2001 to 2010 for the reduction of radiation dose to workers. The plan is aimed for the reduction of annual dose per unit averaged over 5 years from 0.9 man-Sv in 2001 to 0.75 man- Sv in 2010 by radiation source reduction, equipment/tool improvement or new equipment development for easy maintenance, and the improvement of administration and system.

  8. Assessment of dose level of ionizing radiation in army scrap

    International Nuclear Information System (INIS)

    Radiation protection is the science of protecting people and the environment from the harmful effects of ionizing radiation, which includes both particle radiation and high energy radiation. Ionizing radiation is widely used in industry and medicine. Any human activity of nuclear technologies should be linked to the foundation of scientific methodology and baseline radiation culture to avoid risk of radiation and should be working with radioactive materials and expertise to understand, control practices in order to avoid risks that could cause harm to human and environment. The study was conducted in warehouses and building of Sudan air force Khartoum basic air force during September 2010. The goal of this study to estimate the radiation dose and measurement of radioactive contamination of aircraft scrap equipment and increase the culture of radiological safety as well as the concept of radiation protection. The results showed that there is no pollution observed in the contents of the aircraft and the spire part stores outside, levels of radiation dose for the all contents of the aircraft and spire part within the excitable level, except temperature sensors estimated radiation dose about 43 μSv/h outside of the shielding and 12 μSv/h inside the shielding that exceeded the internationally recommended dose level. One of the most important of the identification of eighteen (18) radiation sources used in temperature and fuel level sensors. These are separated from the scrap, collected and stored in safe place. (Author)

  9. Doses and biological effect of ionizing radiation

    International Nuclear Information System (INIS)

    Basic values and their symbols as well as units of physical dosimetry are given. The most important information about biological radiation effects is presented. Polish radiation protection standards are cited. (A.S.)

  10. Research And Investigation To Establish The Database Of Environment Radiation Background For Vietnam (Phase 2009 -2011)

    International Nuclear Information System (INIS)

    Setting up data base of natural radiation background serves for planning socio-economics development in a province as well as the whole country and estimating annual effective dose of population. Beside external irradiation dose caused by the natural radioisotopes in the series 238U, 232Th and 40K in soil, population has been received internal dose caused by the above radioisotopes taken in the body from several ways. In order to complete the database of national radiation background and go to estimate annual effective radiation dose of population in the whole country, this project focus to carry out the works as following: (i) Setting up database of radiation background in the whole country: 150 soil samples that collected in the districts of 46 provinces have been analyzed. The average activity concentration of 238U, 232Th and 40K are 37.86 Bq/kg, 58.88 Bq/kg and 462.78 Bq/kg, respectively. The outdoor, indoor and total annual effective doses are calculated: 0.087±0.036 mSv; 0.488±0.202 mSv and 0.576± 0.240 mSv, respectively. (ii) Setting up database of radiation background of province Ninh Thuan and Quang Nam: The detailed database of radiation background of all villages in Ninh Thuan and Quang Nam has been established. 84 soil samples in Ninh Thuan and 311 in Quang Nam were collected for analyze. The indoor and outdoor radon concentration at sampling positions has been measured. The average activities of 238U, 232Th, 40K, and 222Rn isotopes in Ninh Thuan are reported: 33.50 Bq/kg, 55.43 Bq/kg, 701.12 Bq/kg and 12.1 Bq/m3, 9.5 Bq/m3, respectively. The outdoor, indoor and total annual effective doses in Ninh Thuan are calculated: 0.095±0.029 mSv; 0.529±0.162 mSv and 0.624± 0.382 mSv, respectively. The average activities of 238U, 232Th, 40K, and 222Rn isotopes in Quang Nam are reported: 44.47 Bq/kg, 52.68 Bq/kg, 459.33 Bq/kg, 18.0 Bq/m3. The outdoor, indoor and total annual effective doses are calculated: 0.086±0.039 mSv; 0.482±0.216 mSv and 0.568± 0

  11. Dose Assurance in Radiation Processing Plants

    DEFF Research Database (Denmark)

    Miller, Arne; Chadwick, K.H.; Nam, J.W.

    1983-01-01

    Radiation processing relies to a large extent on dosimetry as control of proper operation. This applies in particular to radiation sterilization of medical products and food treatment, but also during development of any other process. The assurance that proper dosimetry is performed at the radiat...

  12. Audit of radiation dose during balloon mitral valvuloplasty procedure

    Energy Technology Data Exchange (ETDEWEB)

    Livingstone, Roshan S [Department of Radiology, Christian Medical College, Vellore-632004, TN (India); Chandy, Sunil [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); Peace, B S Timothy [Department of Radiology, Christian Medical College, Vellore-632004, TN (India); George, Paul [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); John, Bobby [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); Pati, Purendra [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India)

    2006-12-15

    Radiation doses to patients during cardiological procedures are of concern in the present day scenario. This study was intended to audit the radiation dose imparted to patients during the balloon mitral valvuloplasty (BMV) procedure. Thirty seven patients who underwent the BMV procedure performed using two dedicated cardiovascular machines were included in the study. The radiation doses imparted to patients were measured using a dose area product (DAP) meter. The mean DAP value for patients who underwent the BMV procedure from one machine was 19.16 Gy cm{sup 2} and from the other was 21.19 Gy cm{sup 2}. Optimisation of exposure parameters and radiation doses was possible for one machine with the use of appropriate copper filters and optimised exposure parameters, and the mean DAP value after optimisation was 9.36 Gy cm{sup 2}.

  13. Large-Angular-Scale Anisotropy in the Cosmic Background Radiation

    Science.gov (United States)

    Gorenstein, M. V.; Smoot, G. F.

    1980-05-01

    We report the results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3 K cosmic background radiation. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (.089 cm wavelength) flown on board a U-2 aircraft to 20 km altitude. In eleven flights, between December 1976 and May 1978, the radiometer measured differential intensity between pairs of directions distributed over most of the northern hemisphere with an rms sensitivity of 47 mK Hz{sup 1�}. The measurements how clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fit by a first order spherical harmonic of amplitude 360{+ or -}50km sec{sup -1} toward the direction 11.2{+ or -}0.5 hours of right ascension and 19 {+ or -}8 degrees declination. A simultaneous fit to a combined hypotheses of dipole and quadrupole angular distributions places a 1 mK limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 mK limit on uncorrelated fluctuations (sky-roughness) in the 3 K background on an angular scale of the antenna beam width, about 7 degrees.

  14. Biological effects of low doses of radiation at low dose rate

    International Nuclear Information System (INIS)

    The purpose of this report was to examine available scientific data and models relevant to the hypothesis that induction of genetic changes and cancers by low doses of ionizing radiation at low dose rate is a stochastic process with no threshold or apparent threshold. Assessment of the effects of higher doses of radiation is based on a wealth of data from both humans and other organisms. 234 refs., 26 figs., 14 tabs

  15. KREAM: Korean Radiation Exposure Assessment Model for Aviation Route Dose

    Science.gov (United States)

    Hwang, J.; Dokgo, K.; Choi, E. J.; Kim, K. C.; Kim, H. P.; Cho, K. S. F.

    2014-12-01

    Since Korean Air has begun to use the polar route from Seoul/ICN airport to New York/JFK airport on August 2006, there are explosive needs for the estimation and prediction against cosmic radiation exposure for Korean aircrew and passengers in South Korea from public. To keep pace with those needs of public, Korean government made the law on safety standards and managements of cosmic radiation for the flight attendants and the pilots in 2013. And we have begun to develop our own Korean Radiation Exposure Assessment Model (KREAM) for aviation route dose since last year funded by Korea Meteorological Administration (KMA). GEANT4 model and NRLMSIS 00 model are used for calculation of the energetic particles' transport in the atmosphere and for obtaining the background atmospheric neutral densities depending on altitude. For prediction the radiation exposure in many routes depending on the various space weather effects, we constructed a database from pre-arranged simulations using all possible combinations of R, S, and G, which are the space weather effect scales provided by the National Oceanic and Atmospheric Administration (NOAA). To get the solar energetic particles' spectrum at the 100 km altitude which we set as a top of the atmospheric layers in the KREAM, we use ACE and GOES satellites' proton flux observations. We compare the results between KREAM and the other cosmic radiation estimation programs such as CARI-6M which is provided by the Federal Aviation Agency (FAA). We also validate KREAM's results by comparison with the measurement from Liulin-6K LET spectrometer onboard Korean commercial flights and Korean Air Force reconnaissance flights.

  16. Brain Radiation Information Data Exchange (BRIDE): Integration of experimental data from low-dose ionising radiation research for pathway discovery

    NARCIS (Netherlands)

    C. Karapiperis (Christos); S.J. Kempf (Stefan J.); R. Quintens (Roel); O. Azimzadeh (Omid); V.L. Vidal (Victoria Linares); S. Pazzaglia; D. Bazyka (Dimitry); P.G. Mastroberardino (Pier); Z.G. Scouras (Zacharias G.); S. Tapio (Soile); M.A. Benotmane (Mohammed Abderrafi); C.A. Ouzounis (Christos A.)

    2016-01-01

    textabstractBackground: The underlying molecular processes representing stress responses to low-dose ionising radiation (LDIR) in mammals are just beginning to be understood. In particular, LDIR effects on the brain and their possible association with neurodegenerative disease are currently being ex

  17. Commentary 2 to Cox and Little: radiation-induced oncogenic transformation: the interplay between dose, dose protraction, and radiation quality

    Science.gov (United States)

    Brenner, D. J.; Hall, E. J.

    1992-01-01

    There is now a substantial body of evidence for end points such as oncogenic transformation in vitro, and carcinogenesis and life shortening in vivo, suggesting that dose protraction leads to an increase in effectiveness relative to a single, acute exposure--at least for radiations of medium linear energy transfer (LET) such as neutrons. Table I contains a summary of the pertinent data from studies in which the effect is seen. [table: see text] This phenomenon has come to be known as the "inverse dose rate effect," because it is in marked contrast to the situation at low LET, where protraction in delivery of a dose of radiation, either by fractionation or low dose rate, results in a decreased biological effect; additionally, at medium and high LET, for radiobiological end points such as clonogenic survival, the biological effectiveness is independent of protraction. The quantity and quality of the published reports on the "inverse dose rate effect" leaves little doubt that the effect is real, but the available evidence indicates that the magnitude of the effect is due to a complex interplay between dose, dose rate, and radiation quality. Here, we first summarize the available data on the inverse dose rate effect and suggest that it follows a consistent pattern in regard to dose, dose rate, and radiation quality; second, we describe a model that predicts these features; and, finally, we describe the significance of the effect for radiation protection.

  18. Total Risk Management for Low Dose Radiation Exposures

    International Nuclear Information System (INIS)

    Our civilization is witnessing about century of nuclear age mixed with enormous promises and cataclysmic threats. Nuclear energy seems to encapsulate both potential for pure good and evil or at least we humans are able to perceive that. These images are continuously with us and they are both helping and distracting from making best of nuclear potentials for civilization. Today with nuclear use significantly present and with huge potential to further improve our life with energy and medical use it is of enormous importance to try to have calmed, rational, and objective view on potential risks and certain benefits. Because all use of nuclear energy proved that their immediate risks are negligible (i.e., Three Mile Island and Fukushima) or much smaller than from the other alternatives (i.e., Chernobyl) it seems that the most important issue is the amount of risk from the long term effects to people from exposure to small doses of radiation. A similar issue is present in the increased use of modern computational tomography and other radiation sources use in medicine for examination and therapy. Finally, extreme natural exposures are third such potential risk sources. Definition of low doses varies depending on the way of delivery (i.e., single, multiple or continuous exposures), and for this paper usual dose of 100 mSv is selected as yearly upper amount. There are three very different scientifically supported views on the potential risks from the low doses exposure. The most conservative theory is that all radiation is harmful, and even small increments from background levels (i.e., 2-3 mSv) present additional risk. This view is called linear no threshold theory (LNT) and it is accepted as a regulatory conservative simple approach which guarantees safety. Risk is derived from the extrapolation of the measured effects of high levels of radiation. Opposite theory to LNT is hormesis which assumes that in fact small doses of radiation are helpful and they are improving our

  19. Development of Plant Application Technique of Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek (and others)

    2007-07-15

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources.

  20. Biological indicators for radiation absorbed dose: a review

    International Nuclear Information System (INIS)

    Biological dosimetry has an important role to play in assessing the cumulative radiation exposure of persons working with radiation and also in estimating the true dose received during accidents involving external and internal exposure. Various biodosimetric methods have been tried to estimate radiation dose for the above purposes. Biodosimetric methods include cytogenetic, immunological and mutational assays. Each technique has certain advantages and disadvantages. We present here a review of each technique, the actual method used for detection of dose, the sensitivity of detection and its use in long term studies. (author)

  1. Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia

    International Nuclear Information System (INIS)

    A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h−1 to 500 nGy h−1. The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h−1. This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h−1 (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation. - Highlights: • A methodology is presented to reduce terrestrial gamma dose rate field survey. • Geological background of acid intrusive of granitic type has the highest dose rates. • The mean dose rate is 2 times higher than the world average. • Isodose map of terrestrial gamma radiation for Selangor, Kuala Lumpur and Putrajaya was produced

  2. Radiation Doses Received by the Irish Population 2014

    International Nuclear Information System (INIS)

    People are constantly exposed to a variety of sources of both natural and artificial radioactivity. The radiation dose received by the population from such sources is periodically estimated by the Radiological Protection Institute of Ireland RPII. This report is an update of a population dose assessment undertaken in 2008 and includes the most recent data available on the principal radiation exposure pathways. Wherever possible the collective dose and the resulting average annual dose to an individual living in Ireland, based on the most recently published figure for the population of Ireland, have been calculated for each of the pathways of exposure

  3. A review of the studies on the high background radiation areas of the world

    International Nuclear Information System (INIS)

    The most important places among the well documented high background radiation areas (HBRA) of the world inhabited by sizable populations are : Guarapari (Brazil), Yangjiang (China), Chavara and Manavalakkurichy (India), and Ramsar (Iran). While the source of the high background radiation is monazite deposits in the first three cases, radium in soil/water and radon in air are the sources of high background radiation in Ramsar. In India, there are quite a few monazite placer deposits along its long coastal line: Ullal (Karnataka), Chavara (Kerala), Manavalakkurichy and Kalpakkam (Tamilnadu), and Chatrapur (Orissa). During the last three decades many investigations have been carried out in these areas covering various aspects such as radiation dosimetry, biological effects, ecological effects, epidemiology etc. Reports, often vague and inconclusive, continue to appear in literature on topics like genetic effects, cancer risk, hormesis, radon dose estimates etc. A summary of all the important results reported so far, as well as some thoughts on possible future programmes in these areas are presented. (author). 7 refs., 1 tab., 1 fig

  4. Radiation doses to rodents inhabiting a radioactive waste receiving area

    International Nuclear Information System (INIS)

    A study was conducted of the gamma ray doses to four species of native rodents inhabiting a low level radioactive liquid waste disposal area. Absorbed doses of radiation were measured with lithium fluoride thermoluminescent dosimeters that were implanted subcutaneously. The absorbed radiation doses and 137Cs body burdens were significantly higher for western harvest mice (Reithrodontomys megalotis) than for deer mice (Peromyscus maniculatus), pinon mice (P. truei) and the least chipmunk (Eutamias minimus), reflecting differences in mobility and habitat preferences of the respective species. The average dose received by harvest mice was 26 mrad/day, which was 26% of the highest gamma dose detected at the ground surface in the study plot, although the maximum dose received by individual mice was as high as 45% of the maximum dose rates in the plot. (author)

  5. Space Radiation Quality Factors and the Delta Ray Dose and Dose-Rate Reduction Effectiveness Factor.

    Science.gov (United States)

    Cucinotta, Francis A; Cacao, Eliedonna; Alp, Murat

    2016-03-01

    In this paper, the authors recommend that the dose and dose-rate effectiveness factor used for space radiation risk assessments should be based on a comparison of the biological effects of energetic electrons produced along a cosmic ray particles path in low fluence exposures to high dose-rate gamma-ray exposures of doses of about 1 Gy. Methods to implement this approach are described. PMID:26808878

  6. Review of low dose-rate epidemiological studies and biological mechanisms of dose-rate effects on radiation induced carcinogenesis

    International Nuclear Information System (INIS)

    Radiation protection system adopts the linear non-threshold model with using dose and dose-rate effectiveness factor (DDREF). The dose-rate range where DDREF is applied is below 100 mGy per hour, and it is regarded that there are no dose-rate effects at very low dose rate, less than of the order of 10 mGy per year, even from the biological risk evaluation model based on cellular and molecular level mechanisms for maintenance of genetic integrity. Among low dose-rate epidemiological studies, studies of residents in high natural background areas showed no increase of cancer risks at less than about 10 mGy per year. On the other hand, some studies include a study of the Techa River cohort suggested the increase of cancer risks to the similar degree of Atomic bomb survivor data. The difference of those results was supposed due to the difference of dose rate. In 2014, International Commission on Radiological Protection opened a draft report on stem cell biology for public consultations. The report proposed a hypothesis based on the new idea of stem cell competition as a tissue level quality control mechanism, and suggested that it could explain the dose-rate effects around a few milligray per year. To verify this hypothesis, it would be needed to clarify the existence and the lowest dose of radiation-induced stem cell competition, and to elucidate the rate of stem cell turnover and radiation effects on it. As for the turnover, replenishment of damaged stem cells would be the important biological process. It would be meaningful to collect the information to show the difference of dose rates where the competition and the replenishment would be the predominant processes. (author)

  7. Telomere length in human adults and high level natural background radiation.

    Directory of Open Access Journals (Sweden)

    Birajalaxmi Das

    Full Text Available BACKGROUND: Telomere length is considered as a biomarker of aging, stress, cancer. It has been associated with many chronic diseases such as hypertension and diabetes. Although, telomere shortening due to ionizing radiation has been reported in vitro, no in vivo data is available on natural background radiation and its effect on telomere length. METHODOLOGY/PRINCIPAL FINDINGS: The present investigation is an attempt to determine the telomere length among human adults residing in high level natural radiation areas (HLNRA and the adjacent normal level radiation areas (NLNRA of Kerala coast in Southwest India. Genomic DNA was isolated from the peripheral blood mononuclear cells of 310 individuals (HLNRA: N = 233 and NLNRA: N = 77. Telomere length was determined using real time q-PCR. Both telomere (T and single copy gene (S specific primers were used to calculate the relative T/S and expressed as the relative telomere length. The telomere length was determined to be 1.22+/-0.15, 1.12+/-0.15, 1.08+/-0.08, 1.12+/-0.11, respectively, among the four dose groups (5.00 mGy per year, which did not show any dose response. The results suggested that the high level natural chronic radiation did not have significant effect on telomere length among young adult population living in HLNRA, which is indicative of better repair of telomeric ends. No significant difference in telomere length was observed between male and female individuals. In the present investigation, although the determination of telomere length was studied among the adults with an age group between 18 to 40 years (mean maternal age: 26.10+/-4.49, a negative correlation was observed with respect to age. However, inter-individual variation was (0.81-1.68 was clearly observed. CONCLUSIONS/SIGNIFICANCE: In this preliminary investigation, we conclude that elevated level of natural background radiation has no significant effect on telomere length among the adult population residing in HLNRAs of

  8. Estimating radiation doses from reactor accidents

    International Nuclear Information System (INIS)

    In order to plan for emergency response to reactor accidents involving large radiation releases, it is necessary to determine the medical resources, such as diagnostic laboratory tests, hospital facilities and convalescent care, needed to care for a large population exposed to radiation. A determination of the needed medical resources is difficult because of the widely varying sensitivity humans exhibit to radiation exposure and because of the large number of assumptions involved in predicting radiation dispersion. This paper demonstrates a simple method for approximating medical needs in response to a severe reactor accident. The method requires a model for radiation dispersion from the accident and data for population distribution surrounding the reactor. With this information, tables developed in this paper may be used to project medical needs. The needs identified by this methodology may be compared against the actual medical resources of nearby communities to determine the size of the area impacted

  9. Evaluation of the natural background radiation in City Sopron

    Energy Technology Data Exchange (ETDEWEB)

    Spaits, T. [West Hungary Univ., Institute of Forestry Mechanics (Hungary); Divos, F. [West Hungary Univ., National Radiation Control System - Sopron Unit (Hungary); Kavasi, N. [Veszprem Univ., Dept. of Radiochemistry (Hungary); Boka, Z. [West Hungary Univ., Dept. of Geodetics and Remote Sensing (Hungary)

    2006-07-01

    In the Postgraduate School of the Faculty of Forestry of the University of West Hungary a project with the topic Research of natural radioactive isotopes in our built and natural environs is being run. Preparing this map is an organic part of this PhD research. The measurements are being made in Sopron city and in its next surroundings, trying to estimate, which dose of radiation a citizen of Sopron is exposed, according to his age and lifestyle. The measurements completely cover the built-up area of Sopron, moreover they exceed the confines, so thus they provide information about the natural areas in the vicinity of the city. In figures, the detection carried out in an area of 24 square kilometres, working with a grid mesh of 200 metres. A sodium-iodide detector was used. We have faced several anomalies while mapping. These are the following: On Main Square (Foter), Ursulin Square (Orsolya ter), Paulites Square (Palosok tere, where a higher dose can be measured, due to granite cobbles, used to cover the pavements of the squares and streets. This was confirmed by the gamma spectrometric examination of the granite stones. In these areas, a triple of the mean dose-rate of 70-90 n Sv/h in Sopron was detected. The highest values of 400 n Sv/h were detected in the cinder-covered car-park of the paint store in Koszegi Street. The total gamma activity concentration of the cinder used in the car-park was nearly 2000 Bq/kg. A triple to a quadruple of the natural level was detected in the vicinity of the chimney of the former thermal power plant and the brick factory. The detection was carried out in four directions with raising range starting by the chimneys, which has spectacularly shown, that the sedimentation of the aerosols can be tracked is a function of distance. The measurements have also shown, that there is a significant difference between dose-levels of the natural areas beyond the eastern and western edge of the city, which can be explained with the different

  10. A family of statistical distributions for modelling occupational radiation doses in low dose occupations

    International Nuclear Information System (INIS)

    New statistical distributions have been defined to describe occupational exposures to ionising radiation. These distributions are particularly useful in modelling occupations where most doses are low. The maximum likelihood method was used for parameter estimation and has been adapted to allow doses that are recorded as zero to be included in the calculations. The method can then be applied to estimate true doses from the complete set of recorded dose values when the a priori dose distribution and the dose measurement distributions have been derived previously. This application is important in epidemiological cohort studies where it can improve the accuracy of excess relative risk estimates. (authors)

  11. Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia.

    Science.gov (United States)

    Sanusi, M S M; Ramli, A T; Gabdo, H T; Garba, N N; Heryanshah, A; Wagiran, H; Said, M N

    2014-09-01

    A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h(-1) to 500 nGy h(-1). The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h(-1). This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h(-1) (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation.

  12. Cosmic Background Radiation and `ether-drift' experiments

    CERN Document Server

    Consoli, M; Rapisarda, A

    2016-01-01

    `Ether-drift' experiments have played a crucial role for the origin of relativity. Though, a recent re-analysis shows that those original measurements where light was still propagating in gaseous systems, differently from the modern experiments in vacuum and in solid dielectrics, indicate a small universal anisotropy which is naturally interpreted in terms of a non-local thermal gradient. We argue that this could possibly be the effect, on weakly bound gaseous matter, of the temperature gradient due to the Earth's motion within the Cosmic Background Radiation (CBR). Therefore, a check with modern laser interferometers is needed to reproduce the conditions of those early measurements with today's much greater accuracy. We emphasize that an unambiguous confirmation of our interpretation would have far reaching consequences. For instance, it would also imply that all physical systems on the moving Earth are exposed to a tiny energy flow, an effect that, in principle, could induce forms of self-organization in ma...

  13. Far Infrared Spectrometry of the Cosmic Background Radiation

    Science.gov (United States)

    Mather, J. C.

    1974-01-01

    I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

  14. Characteristic angular scales in cosmic microwave background radiation

    International Nuclear Information System (INIS)

    We investigate the stochasticity in temperature fluctuations in the cosmic microwave background (CMB) radiation data from the Wilkinson Microwave Anisotropy Probe. We show that the angular fluctuation of the temperature is a Markov process with a Markov angular scale, Markov 1.01-0.07+0.09. We characterize the complexity of the CMB fluctuations by means of a Fokker-Planck or Langevin equation and measure the associated Kramers-Moyal coefficients for the fluctuating temperature field T(n-circumflex) and its increment, ΔT = T(n-circumflex1) - T(n-circumflex2). Through this method we show that temperature fluctuations in the CMB have fat tails compared to a Gaussian distribution. (author)

  15. Online Radiation Dose Measurement System for ATLAS experiment

    CERN Document Server

    Mandić, I; The ATLAS collaboration

    2012-01-01

    Particle detectors and readout electronics in the high energy physics experiment ATLAS at the Large Hadron Collider at CERN operate in radiation field containing photons, charged particles and neutrons. The particles in the radiation field originate from proton-proton interactions as well as from interactions of these particles with material in the experimental apparatus. In the innermost parts of ATLAS detector components will be exposed to ionizing doses exceeding 100 kGy. Energetic hadrons will also cause displacement damage in silicon equivalent to fluences of several times 10e14 1 MeV-neutrons per cm2. Such radiation doses can have severe influence on the performance of detectors. It is therefore very important to continuously monitor the accumulated doses to understand the detector performance and to correctly predict the lifetime of radiation sensitive components. Measurements of doses are important also to verify the simulations and represent a crucial input into the models used for predicting future ...

  16. Low dose ionizing radiation induced acoustic neuroma: A putative link?

    Directory of Open Access Journals (Sweden)

    Sachin A Borkar

    2012-01-01

    Full Text Available Although exposure to high dose ionizing radiation (following therapeutic radiotherapy has been incriminated in the pathogenesis of many brain tumors, exposure to chronic low dose ionizing radiation has not yet been shown to be associated with tumorigenesis. The authors report a case of a 50-year-old atomic reactor scientist who received a cumulative dose of 78.9 mSv over a 10-year period and was detected to have an acoustic neuroma another 15 years later. Although there is no proof that exposure to ionizing radiation was the cause for the development of the acoustic neuroma, this case highlights the need for extended follow-up periods following exposure to low dose ionizing radiation.

  17. Radiation dose measurement of paediatric patients in Estonia

    Energy Technology Data Exchange (ETDEWEB)

    Kepler, K. [Training Centre of Medical Physics and Biomedical Engineering, University of Tartu (Estonia); Lintrop, M. [Department of Radiology, Tartu University Hospital, Tartu (Estonia); Servomaa, A.; Parviainen, T. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland); Eek, V.; Filippova, I. [Estonian Radiation Protection Centre, Tallinn (Estonia)

    2003-06-01

    According to the Medical Exposure Directive (97/43/Euratom) the radiation doses to patients should be measured in every hospital and doses should be compared to the reference doses established by the competent authorities. Special attention should be paid to the paediatric x-ray examinations, because the paediatric patients are more radiosensitive than adult patients. The requirement of measurements of radiation dose to patients is not yet included in the Estonian radiation act, but the purpose to join the European Communities makes the quality control in radiology very actual in Estonia. The necessity exists to introduce suitable measurement methods in the Xray departments of Estonian hospitals for establishing feedback system for radiologists, radiographers and medical physicists in optimising the radiation burden of patients and image quality. (orig.)

  18. Biological effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Few weeks ago, when the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) submitted to the U.N. General Assembly the UNSCEAR 1994 report, the international community had at its disposal a broad view of the biological effects of low doses of ionizing radiation. The 1994 report (272 pages) specifically addressed the epidemiological studies of radiation carcinogenesis and the adaptive responses to radiation in cells and organisms. The report was aimed to supplement the UNSCEAR 1993 report to the U.N. General Assembly- an extensive document of 928 pages-which addressed the global levels of radiation exposing the world population, as well as some issues on the effects of ionizing radiation, including: mechanisms of radiation oncogenesis due to radiation exposure, influence of the level of dose and dose rate on stochastic effects of radiation, hereditary effects of radiation effects on the developing human brain, and the late deterministic effects in children. Those two UNSCEAR reports taken together provide an impressive overview of current knowledge on the biological effects of ionizing radiation. This article summarizes the essential issues of both reports, although it cannot cover all available information. (Author)

  19. KERMA-based radiation dose management system for real-time patient dose measurement

    Science.gov (United States)

    Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

    2016-07-01

    Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

  20. Internal dose assessment in radiation accidents

    International Nuclear Information System (INIS)

    Although numerous models have been developed for occupational and medical internal dosimetry, they may not be applicable to an accident situation. Published dose coefficients relate effective dose to intake, but if acute deterministic effects are possible, effective dose is not a useful parameter. Consequently, dose rates to the organs of interest need to be computed from first principles. Standard bioassay methods may be used to assess body contents, but, again, the standard models for bioassay interpretation may not be applicable because of the circumstances of the accident and the prompt initiation of decorporation therapy. Examples of modifications to the standard methodologies include adjustment of biological half-times under therapy, such as in the Goiania accident, and the same effect, complicated by continued input from contaminated wounds, in the Hanford 241Am accident. (author)

  1. Epidemiological investigation of radiological effects in high background radiation areas of Yangjiang, China

    International Nuclear Information System (INIS)

    The purpose of this investigation is to provide some information for providing whether any detrimental effects exist in a large population whose families have been continuously exposed to a low dose rate radiation. Two areas in Yangjiang Country, characterized by high background radiation (HBR) with environmental gamma exposure, large population size and long-term inhabitants, were selected for evaluation of late effects of HBR. The areas with normal radiation background close to the Yangjiang Country were selected as control areas. Up to 1986 approximately one million person-years in each area in both HBR and control areas have been observed. No increase of cancer mortality was found in the HBR areas; on the contrary, cancer mortality tended to be lower in the HBR areas than the control areas. The prevalence of hereditary diseases and congenital defects was similar in both HBR and control areas, but the frequency of Down's syndrome was higher in the HBR areas (through within the normal range) than the control areas. A possible explanation is the difference of age of maternity between the HBR and control areas, and the extremely low frequency in the control areas. Possible factors influencing the incidence of mutationbased diseases were comparable in the HBR and control groups. However, the cultural and educational levels were somewhat different, probably affecting health status and family planning. It is likely that there may be a dose threshold for cancer incidence, but this remains to be determined by further research. (N.K.)

  2. Depth dose and angular dose distribution experiments with high energy electron-photon radiation

    International Nuclear Information System (INIS)

    India's first synchrotron radiation source, Indus-1, is commissioned at the Centre for Advanced Technology (CAT), Indore. Radiation environment of this facility is quite different in comparison to that of nuclear or irradiator facilities and proton or heavy ion accelerator facilities. The primary particle accelerated being the electron, the radiation environment mainly comprises of Bremsstrahlung photons followed by photo-neutrons, whereas electron contamination too exists within the containment area. Due to the complex nature of the radiation viz. high energy, broad energy spectrum, pulsed, mixed field, sharp angular distribution etc. quantification of radiation dose becomes a difficult task. In this paper, experiments on depth dose and angular dose distribution done with 450 MeV electron-photon radiation are described

  3. Radioactivity in the groundwater of a high background radiation area.

    Science.gov (United States)

    Shabana, E I; Kinsara, A A

    2014-11-01

    Natural radioactivity was measured in groundwater samples collected from 37 wells scattered in an inhabited area of high natural background radiation, in a purpose of radiation protection. The study area is adjacent to Aja heights of granitic composition in Hail province, Saudi Arabia. Initial screening for gross α and gross β activities showed levels exceeded the national regulation limits set out for gross α and gross β activities in drinking water. The gross α activity ranged from 0.17 to 5.41 Bq L(-)(1) with an average value of 2.15 Bq L(-)(1), whereas gross β activity ranged from 0.48 to 5.16 Bq L(-)(1), with an average value of 2.60 Bq L(-)(1). The detail analyses indicated that the groundwater of this province is contaminated with uranium and radium ((226)Ra and (228)Ra). The average activity concentrations of (238)U, (234)U, (226)Ra and (228)Ra were 0.40, 0.77, 0.29 and 0.46 Bq L(-)(1), respectively. The higher uranium content was found in the samples of granitic aquifers, whereas the higher radium content was found in the samples of sandstone aquifers. Based on the obtained results, mechanism of leaching of the predominant radionuclides has been discussed in detail.

  4. Evaluation of occupational and patient radiation doses in orthopedic surgery

    Energy Technology Data Exchange (ETDEWEB)

    Sulieman, A. [Salman bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P.O. Box 422, Alkharj (Saudi Arabia); Habiballah, B.; Abdelaziz, I. [Sudan Univesity of Science and Technology, College of Medical Radiologic Sciences, P.O. Box 1908, Khartoum (Sudan); Alzimami, K. [King Saud University, College of Applied Medical Sciences, Radiological Sciences Department, P.O. Box 10219, 11433 Riyadh (Saudi Arabia); Osman, H. [Taif University, College of Applied Medical Science, Radiology Department, Taif (Saudi Arabia); Omer, H. [University of Dammam, Faculty of Medicine, Dammam (Saudi Arabia); Sassi, S. A., E-mail: Abdelmoneim_a@yahoo.com [Prince Sultan Medical City, Department of Medical Physics, Riyadh (Saudi Arabia)

    2014-08-15

    Orthopedists are exposed to considerable radiation dose during orthopedic surgeries procedures. The staff is not well trained in radiation protection aspects and its related risks. In Sudan, regular monitoring services are not provided for all staff in radiology or interventional personnel. It is mandatory to measure staff and patient exposure in order to radiology departments. The main objectives of this study are: to measure the radiation dose to patients and staff during (i) Dynamic Hip Screw (Dhs) and (i i) Dynamic Cannula Screw (Dcs); to estimate the risk of the aforementioned procedures and to evaluate entrance surface dose (ESD) and organ dose to specific radiosensitive patients organs. The measurements were performed in Medical Corps Hospital, Sudan. The dose was measured for unprotected organs of staff and patient as well as scattering radiation. Calibrated Thermoluminescence dosimeters (TLD-Gr-200) of lithium fluoride (LiF:Mg, Cu,P) were used for ESD measurements. TLD signal are obtained using automatic TLD Reader model (Plc-3). The mean patients doses were 0.46 mGy and 0.07 for Dhs and Dcs procedures, respectively. The mean staff doses at the thyroid and chest were 4.69 mGy and 1.21 mGy per procedure. The mean radiation dose for staff was higher in Dhs compared to Dcs. This can be attributed to the long fluoroscopic exposures due to the complication of the procedures. Efforts should be made to reduce radiation exposure to orthopedic patients, and operating surgeons especially those with high work load. Staff training and regular monitoring will reduce the radiation dose for both patients and staff. (Author)

  5. Monitoring of radiation exposure and registration of doses

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    The guide defines the concepts relevant to the monitoring of radiation exposure and working conditions and provides guidelines for determining the necessity of monitoring and subsequently organizing it. In addition, instructions are given for reporting doses to the Dose Register of the Finnish Centre for Radiation and Nuclear Safety (STUK). Also the procedures are described for situations leading to exceptional exposures. (10 refs., 1 tab.).

  6. Iodine 131 therapy patients: radiation dose to staff

    International Nuclear Information System (INIS)

    Metastasis to the skeletal system from follicular thyroid carcinoma may be treated with an oral dose of 131I-NaI. Radiation exposures to hospital personnel attending these patients were calculated as a function of administered dose, distance from the patient and time after administration. Routine or emergency patient handling tasks would not exceed occupational radiation protection guidelines for up to 30 min immediately after administration. The emergency handling of several patients presents the potential for exceeding these guidelines. (author)

  7. Radiation doses to personnel during common angiographic procedures involving DSA

    International Nuclear Information System (INIS)

    In this study, the radiation doses received by the staff are monitored during common angiographic procedures involving digital subtraction angiography (DSA). Doses are assessed by direct measurement using lithium fluoride thermoluminescent dosemeters (TLDs). The entrance surface dose (mGy) at the different locations on each of the staff for the three different procedures are given. As the result, on the whole, the main operator, who is standing closest to the x-ray tube and patient, receive the highest dose while the radiographer receives the lowest dose

  8. Investigation of background radiation and associated anomalies in Rifle, Colorado

    International Nuclear Information System (INIS)

    In addition to examining anomalies and establishing the background gamma exposure rate range, the study presents a formula to convert thousand counts per minute (kcpm) from a gamma scintillator to microroentgen per hour (μRh) for the Rifle region. Also, a method is presented to identify contaminated areas containing excess 226Ra, by using a GR-410 gamma spectrometer. This method is suggested to be applied to all property surveys in the Rifle area. The Wasatch Formation, which outcrops extensively in the Rifle area, was found to have a major influence on the background radiation. Varying potassium concentrations and naturally occurring uranium in this rock unit reveal varying gamma exposure rates. Examining RaTh ratios from laboratory analysis of soil samples or use of RaTh ratios from GR-410 gamma spectrometer readings on site allows discrimination between mill related contamination and naturally occuring radioactivity. Radioactive coal clinkers were found used as fill material throughout the Rifle region and have been determined to be a product of the mill and subject to remediation. Finally, windblown mill tailings contamination is addressed in some detail. Mill tailings redistributed from the Rifle uranium mill tailings piles by prevailing winds were detected extensively on vicinity properties in Rifle. Some radioactive components of the windblown tailings were found to have leached into the subsurface soil. The combination of Wasatch Formation, radioactive coal clinkers, and windblown tailings accounts for many of the anomalous gamma exposure rates observed by the radiological survey teams. 11 refs., 10 figs., 3 tabs

  9. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors.

    Science.gov (United States)

    Sasaki, Masao S; Tachibana, Akira; Takeda, Shunichi

    2014-05-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to (239)Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation-environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking. PMID:24366315

  10. The effects of small doses of radiation

    International Nuclear Information System (INIS)

    The following topics were discussed in outline at a two day conference organized by I.B.C. Technical Services Ltd, February 1989, in London: radiation carcinogenesis mechanisms, environmental exposure, occupational exposure trends and comparisons, ICRP risk assessment and use of data including that of A-Bomb survivors, the ankylosing spondylitis study, UKAEA and AWE mortality studies, Sellafield, leukemia clusters and radiation hormesis. (UK)

  11. Dose Response for Chromosome Aberrations in Human Lymphocytes and Fibroblasts After Exposure to Very Low Dose of High Let Radiation

    Science.gov (United States)

    Hada, M.; George, K.; Chappell, L.; Cucinotta, F. A.

    2011-01-01

    The relationship between biological effects and low doses of absorbed radiation is still uncertain, especially for high LET radiation exposure. Estimates of risks from low-dose and low-dose-rates are often extrapolated using data from Japanese atomic bomb survivor with either linear or linear quadratic models of fit. In this study, chromosome aberrations were measured in human peripheral blood lymphocytes and normal skin fibroblasts cells after exposure to very low dose (0.01 - 0.20 Gy) of 170 MeV/u Si-28 ions or 600 MeV/u Fe-56 ions, including doses where on average less than one direct ion traversal per cell nucleus occurs. Chromosomes were analyzed using the whole-chromosome fluorescence in situ hybridization (FISH) technique during the first cell division after irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). The responses for doses above 0.1 Gy (more than one ion traverses a cell) showed linear dose responses. However, for doses less than 0.1 Gy, both Si-28 ions and Fe-56 ions showed a dose independent response above background chromosome aberrations frequencies. Possible explanations for our results are non-targeted effects due to aberrant cell signaling [1], or delta-ray dose fluctuations [2] where a fraction of cells receive significant delta-ray doses due to the contributions of multiple ion tracks that do not directly traverse cell nuclei where chromosome aberrations are scored.

  12. Adaptive response in frogs chronically exposed to low doses of ionizing radiation in the environment

    International Nuclear Information System (INIS)

    Using the micronucleus assay, decreased levels of DNA damage were found after high dose ionizing radiation exposure of liver cells taken from frogs inhabiting a natural environment with above-background levels of ionizing radiation, compared to cells taken from frogs inhabiting background areas. The data obtained from a small number of animals suggest that stress present in the above-background environment could induce an adaptive response to ionizing radiation. This study did not reveal harmful effects of exposure to low levels of radioactivity. On the contrary, stress present in the above-background area may serve to enhance cellular defense mechanisms. - Highlights: → Frogs were collected from background and higher tritium level habitats. → The micronucleus assay was conducted on liver cells obtained from the frogs. → No detrimental effects were noted in frogs exposed to elevated tritium. → Adaptive responses were observed in frogs exposed to elevated tritium.

  13. Adaptive response in frogs chronically exposed to low doses of ionizing radiation in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Audette-Stuart, M., E-mail: stuartm@aecl.ca [Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1P0 (Canada); Kim, S.B.; McMullin, D.; Festarini, A.; Yankovich, T.L.; Carr, J.; Mulpuru, S. [Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1P0 (Canada)

    2011-06-15

    Using the micronucleus assay, decreased levels of DNA damage were found after high dose ionizing radiation exposure of liver cells taken from frogs inhabiting a natural environment with above-background levels of ionizing radiation, compared to cells taken from frogs inhabiting background areas. The data obtained from a small number of animals suggest that stress present in the above-background environment could induce an adaptive response to ionizing radiation. This study did not reveal harmful effects of exposure to low levels of radioactivity. On the contrary, stress present in the above-background area may serve to enhance cellular defense mechanisms. - Highlights: > Frogs were collected from background and higher tritium level habitats. > The micronucleus assay was conducted on liver cells obtained from the frogs. > No detrimental effects were noted in frogs exposed to elevated tritium. > Adaptive responses were observed in frogs exposed to elevated tritium.

  14. The dose makes the poison. Even for radiation

    International Nuclear Information System (INIS)

    The dose makes the poison, a quote by Paracelsus a doctor who lived half a millennium ago, is still valid today. Nevertheless this general accepted fact is being excluded in relation to ionizing radiation, which is wrongly considered as radioactive radiation. Here applies the LNT-Hypothesis (Linear No Threshold), agreed on by the ICRP, the Commission on Radiological Protection, a dose-to-effect relationship, which is based on the EU directives and the German Radiation Protection Ordinance. The LNT-hypothesis states, that even every smallest dose of radiation already provides a potentiality of danger and was introduced as precaution assuming that self-healing mechanisms even through weak radiation of damaged cells can be excluded and every damage caused by radiation inevitably leads to cell mutation and with it to cancer development. Without any further knowledge assumptions were made, that the same mechanism for cancer development applies for high and small doses. This assumption turned out to be wrong, as it is increasingly reported on findings which show, that smaller doses of ionized radiation demonstrably does not cause any damage, but on the contrary can even be healthy.

  15. Radiation Dose to the Thyroid and Gonads in Patients Undergoing Cardiac CT Angiography

    OpenAIRE

    Behroozi, Hamid; Davoodi, Mohammad; Aghasi, Shahriar

    2015-01-01

    Background: The present data show a global increase in the rate of cardiovascular disease. Cardiac CT angiography has developed as a fast and non-invasive cardiac imaging modality following the introduction of multi-slice computed tomogaraphy. Objectives: The aim of this study was to measure the radiation dose to the thyroid and pelvis regions in patients undergoing cardiac CT angiography using the Care Dose 4D method of 64-slice scanner. Patients and Methods: Eighty-one patients (41 males an...

  16. Issues in Low Dose Radiation Biology: The Controversy Continues. A Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, William F.; Bair, William J.

    2013-05-01

    Both natural and man-made sources of ionizing radiation contribute to human exposure and consequently pose a risk to human health. Much of this is unavoidable, e.g., natural background radiation, and as the use of radiation in modern medicine and industry increases so does the potential health risk. This perspective reflects the author’s view of current issues in low dose radiation biology research, highlights some of the controversies therein, and suggests areas of future research to address these issues. The views expressed here are the authors own and do not represent any institution, organization or funding body.

  17. Mutation process at low or high radiation doses

    International Nuclear Information System (INIS)

    A concise review is given of the status of research on the genetic effects of low-level radiation in general. The term ''low dose'' is defined and current theories on low dose are set out. Problems and their solutions are discussed. (author)

  18. Radiation Dose-Volume Effects in the Esophagus

    International Nuclear Information System (INIS)

    Publications relating esophageal radiation toxicity to clinical variables and to quantitative dose and dose-volume measures derived from three-dimensional conformal radiotherapy for non-small-cell lung cancer are reviewed. A variety of clinical and dosimetric parameters have been associated with acute and late toxicity. Suggestions for future studies are presented.

  19. The clinical demand for information and the radiation dose in pelvimetry and amniography

    International Nuclear Information System (INIS)

    Radiographic measurements are an important part of antenatal care and are in fact used to a great extent in nulliparous women. In view of this clinical background and also for ethical reasons, reduction of the radiation doses is mandatory. As radiographic pelvimetry is used in so many pregnant women, it is of importance that no higher radiation doses are applied than are absolutely needed to guarantee correct and necessary information. Dose reduction is afforded in two different ways - by optimizing the imaging techniques and by closing a suitable film-screen combination. Measurement of absorbed doses in patients was carried out with highly sensitive lithium fluoride thermoluminiscence dosimeters (TLD) with a dimension of 3x3x0.9 mm (Harshaw type TLD-100). All TLD probes were calibrated with Co60 radiation between the measurement series. Absorbed radiation doses were measured in the rectum for different film-screen combinations. Depending on the position of the fetus in relation to the maternal pelvis, it is obvious that in any individual case varying parts of the fetus will lie directly in the radiation beam. In amniography the absorbed radiation doses will vary from case to case depending on the number of exposures, which should not exceed six, and the duration of fluoroscopy, which should be no longer than 1 min. With the use of lanex Regular screens and highly coned images the radiation dose will not exceed 3.0 mGy. Since a high image quality is mandatory for evaluation of disorders in the fetal skeleton, measurements were not performed with other high-speed screens. The MR 800 screen appears to provide further reduction of the radiation dose in this type of examination. (orig./MG)

  20. Environmental policy. Ambient radioactivity levels and radiation doses in 1996

    International Nuclear Information System (INIS)

    The report is intended as information for the German Bundestag and Bundesrat as well as for the general population interested in issues of radiological protection. The information presented in the report shows that in 1996, the radiation dose to the population was low and amounted to an average of 4 millisievert (mSv), with 60% contributed by natural radiation sources, and 40% by artificial sources. The major natural source was the radioactive gas radon in buildings. Anthropogenic radiation exposure almost exclusively resulted from application of radioactive substances and ionizing radiation in the medical field, for diagnostic purposes. There still is a potential for reducing radiation doses due to these applications. In the reporting year, there were 340 000 persons occupationally exposed to ionizing radiation. Only 15% of these received a dose different from zero, the average dose was 1.8 mSv. The data show that the anthropogenic radiation exposure emanating from the uses of atomic energy or applications of ionizing radiation in technology is very low. (orig./CB)

  1. Sensors of absorbed dose of ionizing radiation based on mosfet

    OpenAIRE

    Perevertaylo V. L.

    2010-01-01

    The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  2. Therapeutic effects of low radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Trott, K.R. (Dept. of Radiation Biology, St. Bartholomew' s Medical College, London (United Kingdom))

    1994-01-01

    This editorial explores the scientific basis of radiotherapy with doses of < 1 Gy for various non-malignant conditions, in particular dose-effect relationships, risk-benefit considerations and biological mechanisms. A review of the literature, particularly clinical and experimental reports published more than 50 years ago was conducted to clarify the following problems. 1. The dose-response relationships for the therapeutic effects on three groups of conditions: non-malignant skin disease, arthrosis and other painful degenerative joint disorders and anti-inflammatory radiotherapy; 2. risks after radiotherapy and after the best alternative treatments; 3. the biological mechanisms of the different therapeutic effects. Radiotherapy is very effective in all three groups of disease. Few dose-finding studies have been performed, all demonstrating that the optimal doses are considerable lower than the generally recommended doses. In different conditions, risk-benefit analysis of radiotherapy versus the best alternative treatment yields very different results: whereas radiotherapy for acute postpartum mastitis may not be justified any more, the risk-benefit ratio of radiotherapy of other conditions and particularly so in dermatology and some anti-inflammatory radiotherapy appears to be more favourable than the risk-benefit ratio of the best alternative treatments. Radiotherapy can be very effective treatment for various non-malignant conditions such as eczema, psoriasis, periarthritis humeroscapularis, epicondylitis, knee arthrosis, hydradenitis, parotitis and panaritium and probably be associated with less acute and long-term side effects than similarly effective other treatments. Randomized clinical studies are required to find the optimal dosage which, at present, may be unnecessarily high.

  3. Two pediatric cases of high dose radiation-induced meningiomas

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Miho [National Yokosuka Hospital, Kanagawa (Japan); Nagashima, Goro; Fujimoto, Tsukasa; Aoyagi, Masaru; Takasato, Yoshio

    2001-10-01

    There have been many reports of low dose radiation-induced meningiomas, and the number of reports of high dose radiation-induced meningiomas has been increasing recently. In this report, we present two cases of pediatric radiation-induced meningiomas, one 14 years after 36 Gy of radiation therapy for medulloblastoma and the other 8 years after 20 Gy of local radiation therapy for germinoma. Both patients underwent surgical removal of the meningiomas. The case of medulloblastoma was later revealed to be basal cell phacomatosis syndrome. Basal cell phacomatosis syndrome is a disease that occurs as a result of abnormality of chromosome 9. We speculate that the occurrence of radiation-induced meningioma may have been related to the basic genetic vulnerability of the patients. (author)

  4. Radiation Dose from Lunar Neutron Albedo

    Science.gov (United States)

    Adams, J. H., Jr.; Bhattacharya, M.; Lin, Zi-Wei; Pendleton, G.

    2006-01-01

    The lunar neutron albedo from thermal energies to 8 MeV was measured on the Lunar Prospector Mission in 1998-1999. Using GEANT4 we have calculated the neutron albedo due to cosmic ray bombardment of the moon and found a good-agreement with the measured fast neutron spectra. We then calculated the total effective dose from neutron albedo of all energies, and made comparisons with the effective dose contributions from both galactic cosmic rays and solar particle events to be expected on the lunar surface.

  5. Radiation Dose-Response Relationships and Risk Assessment

    International Nuclear Information System (INIS)

    The notion of a dose-response relationship was probably invented shortly after the discovery of poisons, the invention of alcoholic beverages, and the bringing of fire into a confined space in the forgotten depths of ancient prehistory. The amount of poison or medicine ingested can easily be observed to affect the behavior, health, or sickness outcome. Threshold effects, such as death, could be easily understood for intoxicants, medicine, and poisons. As Paracelsus (1493-1541), the 'father' of modern toxicology said, 'It is the dose that makes the poison.' Perhaps less obvious is the fact that implicit in such dose-response relationships is also the notion of dose rate. Usually, the dose is administered fairly acutely, in a single injection, pill, or swallow; a few puffs on a pipe; or a meal of eating or drinking. The same amount of intoxicants, medicine, or poisons administered over a week or month might have little or no observable effect. Thus, before the discovery of ionizing radiation in the late 19th century, toxicology ('the science of poisons') and pharmacology had deeply ingrained notions of dose-response relationships. This chapter demonstrates that the notion of a dose-response relationship for ionizing radiation is hopelessly simplistic from a scientific standpoint. While useful from a policy or regulatory standpoint, dose-response relationships cannot possibly convey enough information to describe the problem from a quantitative view of radiation biology, nor can they address societal values. Three sections of this chapter address the concepts, observations, and theories that contribute to the scientific input to the practice of managing risks from exposure to ionizing radiation. The presentation begins with irradiation regimes, followed by responses to high and low doses of ionizing radiation, and a discussion of how all of this can inform radiation risk management. The knowledge that is really needed for prediction of individual risk is presented

  6. Radiation Dose from Medical Imaging: A Primer for Emergency Physicians

    OpenAIRE

    Jones, Jesse G.A; Mills, Christopher N.; Mogensen, Monique A.; Lee, Christoph I.

    2012-01-01

    Introduction: Medical imaging now accounts for most of the US population’s exposure to ionizing radiation. A substantial proportion of this medical imaging is ordered in the emergency setting. We aim to provide a general overview of radiation dose from medical imaging with a focus on computed tomography, as well as a literature review of recent efforts to decrease unnecessary radiation exposure to patients in the emergency department setting. Methods: We conducted a literature revie...

  7. Molecular targets for radioprotection by low dose radiation exposure

    International Nuclear Information System (INIS)

    Adaptive response is a reduced effect from a higher challenging dose of a stressor after a smaller inducing dose had been applied a few hrs earlier. Radiation induced fibrosarcoma (RIF) cells did not show such an adaptive response, i.e. a reduced effect from a higher challenging dose (2 Gy) of a radiation after a priming dose (1 cGy) had been applied 4 or 7 hrs earlier, but its thermoresistant clone (TR) did. Since inducible HSP70 and HSP25 expressions were different between these two cell lines, the role of inducible HSP70 and HSP25 in adaptive response was examined. When inducible hsp70 or hsp25 genes were transfected to RIF cells, radioresistance in clonogenic survival and reduction of apoptosis was detected. The adaptive response was also acquired in these two cell lines, and inducible hsp70 transfectant showed more pronounced adaptive response than hsp25 transfectant. From these results, inducible HSP70 and HSP25 are at least partly responsible for the induction of adaptive response in these cells. Moreover, when inducible HSP70 or HSP25 genes were transfected to RIF cells, coregulation of each gene was detected and heat shock factor (HSF) was found to be responsible for these phenomena. In continuation of our earlier study on the involvement of heat shock protein (HSP) 25 and HSP70 in the induction of adaptive response, we have now examined the involvement of these proteins in the induction of the adaptive response, using an animal model system. C57BL6 mice were irradiated with 5 cGy of gamma radiation 3 times for a week (total of 15cGy) and a high challenge dose (6Gy) was given on the day following the last low dose irradiation. Survival rate of the low dose pre-irradiated mice was increased to 30%. Moreover, high dose-mediated induction of apoptosis was also reduced by low dose pre-irradiation. To elucidate any link existing between HSP and induction of the adaptive response, reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis was performed

  8. Effective UV radiation dose in polyethylene exposed to weather

    Science.gov (United States)

    González-Mota, R.; Soto-Bernal, J. J.; Rosales-Candelas, I.; Calero Marín, S. P.; Vega-Durán, J. T.; Moreno-Virgen, R.

    2009-09-01

    In this work we quantified the effective UV radiation dose in orange and colorless polyethylene samples exposed to weather in the city of Aguascalientes, Ags. Mexico. The spectral distribution of solar radiation was calculated using SMART 2.9.5.; the samples absorption properties were measured using UV-Vis spectroscopy and the quantum yield was calculated using samples reflectance properties. The determining factor in the effective UV dose is the spectral distribution of solar radiation, although the chemical structure of materials is also important.

  9. Do changes in biomarkers from space radiation reflect dose or risk?

    Science.gov (United States)

    Brooks, A.

    . Following low-LET radiation exposure, the biological response often does not increase as a linear function of dose. Thus, the RBE and the subsequent risk predicted is dependent on the dose where the two radiation types are compared. To avoid this problem the standard procedure is to use the dose and dose-rate response and compare the linear components of the two r diation exposures. Important riska comparisons are often done at very low doses, where the reference radiation may either increase or decrease as a function of dose. Since the low-LET exposure often does not produce a significant change above the background level of damage, the derived RBE factors can become very large.Studies using micronuclei as biomarkers following exposure to mono-energetic neutrons, x-rays and gamma rays delivered at very low doses (up to 0.10 Gy) demonstrated the differences in the shape of each dose-response relationship and the problems associated with the RBE. These studies show that RBE may not accurately reflect the hazards or risk associated with space radiation exposure. As additional measures of biological change are developed, it may become possible to base risk on biological change and not on changes in radiation doses. Research funded through grants # DE-FG03-99ER62787 from DOE Office of Biological and Environmental Research and RO1 CA74053-01 from NIH/NASA to Washington State University Tri-Cities.

  10. Radiation doses to children with shunt-treated hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    Holmedal, Lise J. [Helse Fonna, Department of Radiology, Stord Hospital, Stord (Norway); Friberg, Eva G.; Boerretzen, Ingelin; Olerud, Hilde [The Norwegian Radiation Protection Authority, Oesteraas (Norway); Laegreid, Liv [Haukeland University Hospital, Department of Paediatrics, Bergen (Norway); Rosendahl, Karen [University of Bergen, Department of Surgical Sciences, Radiology Section, Bergen (Norway); Great Ormond Street Hospital for Children, Department of Diagnostic Radiology, London (United Kingdom)

    2007-12-15

    Children with shunt-treated hydrocephalus are still followed routinely with frequent head CT scans. To estimate the effective dose, brain and lens doses from these examinations during childhood, and to assess dose variation per examination. All children born between 1983 and 1995 and treated for hydrocephalus between 1983 and 2002 were included. We retrospectively registered the number of examinations and the applied scan parameters. The effective dose was calculated using mean conversion factors from the CT dose index measured free in air, while doses to the lens and brain were estimated using tabulated CT dose index values measured in a head phantom. A total of 687 CT examinations were performed in 67 children. The mean effective dose, lens dose and brain dose to children over 6 months of age were 1.2 mSv, 52 mGy and 33 mGy, respectively, and the corresponding doses to younger children were 3.2 mSv, 60 mGy and 48 mGy. The effective dose per CT examination varied by a factor of 64. None of the children was exposed to doses known to cause deterministic effects. However, since the threshold for radiation-induced damage is not known with certainty, alternative modalities such as US and MRI should be used whenever possible. (orig.)

  11. Dose received by radiation workers in Australia, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Morris, N.D.

    1994-07-01

    Exposure to radiation can cause genetic defects or cancer. People who use sources of radiation as part of their employment are potentially at a greater risk than others owing to the possibility of their being continually exposed to small radiation doses over a long period. In Australia, the National Health and Medical Research Council has established radiation protection standards and set annual effective dose limits for radiation workers in order to minimise the chance of adverse effects occurring. These standards are based on the the recommendations of the International Commission on Radiological Protection (ICRP 1990). In order to ensure that the prescribed limits are not exceeded and to ensure that doses are kept to a minimum, some sort of monitoring is necessary. The primary purpose of this report is to provide data on the distribution of effective doses for different occupational categories of radiation worker in Australia. The total collective effective dose was found to be of the order of 4.9 Sv for a total of 34750 workers. 9 refs., 16 tabs., 6 figs.

  12. Radiation dose estimates for carbon-11-labelled PET tracers

    International Nuclear Information System (INIS)

    Introduction: Carbon-11-labelled positron emission tomography (PET) tracers commonly used in biomedical research expose subjects to ionising radiation. Dosimetry is the measurement of radiation dose, but also commonly refers to the estimation of health risk associated with ionising radiation. This review describes radiation dosimetry of carbon-11-labelled molecules in the context of current PET research and the most widely used regulatory guidelines. Methods: A MEDLINE literature search returned 42 articles; 32 of these were based on human PET data dealing with radiation dosimetry of carbon-11 molecules. Radiation burden expressed as effective dose and maximum absorbed organ dose was compared between tracers. Results: All but one of the carbon-11-labelled PET tracers have an effective dose under 9 μSv/MBq, with a mean of 5.9 μSv/MBq. Data show that serial PET scans in a single subject are feasible for the majority of radiotracers. Conclusion: Although differing in approach, the two most widely used regulatory frameworks (those in the USA and the EU) do not differ substantially with regard to the maximum allowable injected activity per PET study. The predictive validity of animal dosimetry models is critically discussed in relation to human dosimetry. Finally, empirical PET data are related to human dose estimates based on homogenous distribution, generic models and maximum cumulated activities. Despite the contribution of these models to general risk estimation, human dosimetry studies are recommended where continued use of a new PET tracer is foreseen.

  13. Status of eye lens radiation dose monitoring in European hospitals

    International Nuclear Information System (INIS)

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. (paper)

  14. Direct determination of radiation dose in human blood

    CERN Document Server

    Tanir, Ayse Gunes; Sahiner, Eren; Bolukdemir, Mustafa Hicabi; Koc, Kemal; Meric, Niyazi; Kelec, Sule Kaya

    2014-01-01

    Our purpose is to measure the internal radiation dose (ID) using human blood sample. In the literature, there is no process that allows the direct measurement of ID received by a person. This study has shown that it is possible to determine ID in human blood exposed to internal or external ionizing radiation treatment both directly and retrospectively. OSL technique was used to measure the total dose from the blood sample. OSL counts from the waste blood of the patient injected with a radiopharmaceutical for diagnostic or treatment purposes and from a blood sample having a laboratory-injected radiation dose were both used for measurements. The decay and dose-response curves (DRC) were plotted for different doses. The doses received by different blood aliquots have been determined by interpolating the natural luminescence counts to DRC. In addition, OSL counts from a healthy blood sample exposed to an external radiation source were measured. The blood aliquots were given different 0-200Gy beta doses and their ...

  15. Investigation of radiation doses in open space using TLD detectors

    Energy Technology Data Exchange (ETDEWEB)

    Reitz, G.; Facius, R.; Bilski, P.; Olko, P

    2002-07-01

    The low energy component of the cosmic radiation field is strongly modified by the shielding of the spacecraft and it is time and location dependent. Thermoluminescent lithium fluoride detectors have been applied to determine the radiation doses inside the ESA-Facility BIOPAN. The BIOPAN facility was mounted outside and launched on a Foton spacecraft and opened to space to allow exposure of several experiments to open space. Standard TLD-600, TLD-700 chips, two layers MTS-Ns sintered pellets with different effective thickness of the sensitive layer and MTS-N of different thickness have been exposed with different shielding thickness in front of them. The measured TL signal in the 0.1 mm thick detector just shielded by an aluminised Kapton foil of 25 {mu}m thickness in front yielded a dose of 29.8 Gy (calibrated with {sup 137}Cs gamma rays) for an exposure time of 12.7 days; after 2.5 gcm{sup -2} shielding the doses dropped to 3 mGy. The monitoring of radiation doses and its depth dose distribution outside the spacecraft are of great interest for radiation protection of astronauts working in the open space. The knowledge of depth-dose distribution is a prerequisite to determine the organ doses an astronaut will receive during an extravehicular activity. The BIOPAN experiments are to be continued in the future. (author)

  16. Investigation of radiation doses in open space using TLD detectors.

    Science.gov (United States)

    Reitz, G; Facius, R; Bilski, P; Olko, P

    2002-01-01

    The low energy component of the cosmic radiation field is strongly modified by the shielding of the spacecraft and it is time and location dependent. Thermoluminescent lithium fluoride detectors have been applied to determine the radiation doses inside the ESA-Facility BIOPAN. The BIOPAN facility was mounted outside and launched on a Foton spacecraft and opened to space to allow exposure of several experiments to open space. Standard TLD-600. TLD-700 chips, two layers MTS-Ns sintered pellets with different effective thickness of the sensitive layer and MTS-N of different thickness have been exposed with different shielding thicknesses in front of them. The measured TL signal in the 0.1 mm thick detector just shielded by an aluminised Kapton foil of 25 microm thickness in front yielded a dose of 29.8 Gy (calibrated with 137Cs gamma rays) for an exposure time of 12.7 days: after 2.5 g.cm(-2) shielding the doses dropped to 3 mGy. The monitoring of radiation doses and its depth dose distribution outside the spacecraft are of great interest for radiation protection of astronauts working in open space. The knowledge of depth-dose distribution is a prerequisite to determine the organ doses an astronaut will receive during an extravehicular activity (EVA). The BIOPAN experiments are to be continued in the future. PMID:12382937

  17. Errors and Uncertainties in Dose Reconstruction for Radiation Effects Research

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J.

    2008-04-14

    Dose reconstruction for studies of the health effects of ionizing radiation have been carried out for many decades. Major studies have included Japanese bomb survivors, atomic veterans, downwinders of the Nevada Test Site and Hanford, underground uranium miners, and populations of nuclear workers. For such studies to be credible, significant effort must be put into applying the best science to reconstructing unbiased absorbed doses to tissues and organs as a function of time. In many cases, more and more sophisticated dose reconstruction methods have been developed as studies progressed. For the example of the Japanese bomb survivors, the dose surrogate “distance from the hypocenter” was replaced by slant range, and then by TD65 doses, DS86 doses, and more recently DS02 doses. Over the years, it has become increasingly clear that an equal level of effort must be expended on the quantitative assessment of uncertainty in such doses, and to reducing and managing uncertainty. In this context, this paper reviews difficulties in terminology, explores the nature of Berkson and classical uncertainties in dose reconstruction through examples, and proposes a path forward for Joint Coordinating Committee for Radiation Effects Research (JCCRER) Project 2.4 that requires a reasonably small level of effort for DOSES-2008.

  18. Low-Dose Radiation Cataract and Genetic Determinants of Radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kleiman, Norman Jay [Columbia University

    2013-11-30

    The lens of the eye is one of the most radiosensitive tissues in the body. Ocular ionizing radiation exposure results in characteristic, dose related, progressive lens changes leading to cataract formation. While initial, early stages of lens opacification may not cause visual disability, the severity of such changes progressively increases with dose until vision is impaired and cataract extraction surgery may be required. Because of the transparency of the eye, radiation induced lens changes can easily be followed non-invasively over time. Thus, the lens provides a unique model system in which to study the effects of low dose ionizing radiation exposure in a complex, highly organized tissue. Despite this observation, considerable uncertainties remain surrounding the relationship between dose and risk of developing radiation cataract. For example, a growing number of human epidemiological findings suggest significant risk among various groups of occupationally and accidentally exposed individuals and confidence intervals that include zero dose. Nevertheless, questions remain concerning the relationship between lens opacities, visual disability, clinical cataract, threshold dose and/or the role of genetics in determining radiosensitivity. Experimentally, the response of the rodent eye to radiation is quite similar to that in humans and thus animal studies are well suited to examine the relationship between radiation exposure, genetic determinants of radiosensitivity and cataractogenesis. The current work has expanded our knowledge of the low-dose effects of X-irradiation or high-LET heavy ion exposure on timing and progression of radiation cataract and has provided new information on the genetic, molecular, biochemical and cell biological features which contribute to this pathology. Furthermore, findings have indicated that single and/or multiple haploinsufficiency for various genes involved in DNA repair and cell cycle checkpoint control, such as Atm, Brca1 or Rad9

  19. Occupational radiation doses in Portugal from 1994 to 1998

    International Nuclear Information System (INIS)

    This work reports on the occupational radiation doses for external radiation received in 1994-1998 by the radiation workers monitored by the Radiological Protection and Nuclear Safety Department (DPRSN) in Portugal. Individual monitoring for external radiation is carried out in Portugal by DPRSN since the 60s, and the workers are monitored on a monthly or quarterly bases. In 1995 DPRSN monitored approximately 8000 people and was the only laboratory carrying out this sort of activity in Portugal. In 1998 the number of monitored people increased to nearly 8500 from 860 facilities, which leads us to state that the results shown in this work are well representative of the universe of radiation workers in Portugal. Until 1996, the dose measurement procedure was based only on film dosimetry and the results reported for the 1994-1995 period were obtained with this methodology. Since 1996, thermoluminescent dosimetry (TLD) was gradually introduced and since then an effort has been made to transfer the monitored workers from film to TLD. In 1998, both film and TLD dosimetry systems were running simultaneously, with average numbers of 4500 workers monitored with film dosimetry, while 4000 were monitored with TLD. The data presented from 1996 to 1998 were obtained with both methodologies. This work reports the annual mean effective doses received from external radiation, for the monitored and exposed workers in the different fields of activity, namely, industry, research laboratories, health and mining. The distribution of the annual effective dose by dose intervals is also reported. The collective annual dose by field of activity is estimated and the contribution to the total annual collective dose is determined. The collective dose estimates for the period 1994 to 1998 demonstrated that the health sector is the most representative exposed group in Portugal. (author)

  20. Time-dependent radiation dose simulations during interplanetary space flights

    Science.gov (United States)

    Dobynde, Mikhail; Shprits, Yuri; Drozdov, Alexander; Hoffman, Jeffrey; Li, Ju

    2016-07-01

    Space radiation is one of the main concerns in planning long-term interplanetary human space missions. There are two main types of hazardous radiation - Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR). Their intensities and evolution depend on the solar activity. GCR activity is most enhanced during solar minimum, while the most intense SEPs usually occur during the solar maximum. SEPs are better shielded with thick shields, while GCR dose is less behind think shields. Time and thickness dependences of the intensity of these two components encourage looking for a time window of flight, when radiation intensity and dose of SEP and GCR would be minimized. In this study we combine state-of-the-art space environment models with GEANT4 simulations to determine the optimal shielding, geometry of the spacecraft, and launch time with respect to the phase of the solar cycle. The radiation environment was described by the time-dependent GCR model, and the SEP spectra that were measured during the period from 1990 to 2010. We included gamma rays, electrons, neutrons and 27 fully ionized elements from hydrogen to nickel. We calculated the astronaut's radiation doses during interplanetary flights using the Monte-Carlo code that accounts for the primary and the secondary radiation. We also performed sensitivity simulations for the assumed spacecraft size and thickness to find an optimal shielding. In conclusion, we present the dependences of the radiation dose as a function of launch date from 1990 to 2010, for flight durations of up to 3 years.

  1. Radon-thoron exposures in high background radiation areas: a review

    International Nuclear Information System (INIS)

    The radon-thoron measurements reported in literature for the high background radiation areas (HBRAs) of the world are summarised here. The most important areas covered are the Radon Spas and the thorium bearing monazite deposits. Special mention is made of the ongoing programmes of radon-thoron survey in the monazite beach areas of India; preliminary measurements indicate significant levels of thoron exposures. The diurnal and seasonal variations are quite wide underscoring the importance of carrying out integrated measurements for meaningful assessments of population exposures. Radon-thoron inhalation dose rates upto 30 mSv/y have been measured in lran as well as India. It has been generally observed that the cumulative population doses due to radon-thoron inhalation are as high as those due to the external exposures in these HBRAs. (author). 7 refs., 2 tabs., 3 figs

  2. Space radiation absorbed dose distribution in a human phantom.

    Science.gov (United States)

    Badhwar, G D; Atwell, W; Badavi, F F; Yang, T C; Cleghorn, T F

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  3. Radiation-dose consequences of acid rain

    International Nuclear Information System (INIS)

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially Ra and Cs, are among these materials. Generally, a decrease in soil pH by 1 unit will cause increases in mobility and plant uptake by factors of 2 to 7. Several simulation models were tested with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modelled a typical, acid rain sensitive soil using meterological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed direct proportionality between the mobility of the nuclides and dose. Based on the literature available, a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor or 2 or more. This will lead to increases in plant uptake and ultimate dose to man of about the same extent

  4. Radiation dose assessments for materials with elevated natural radioactivity

    International Nuclear Information System (INIS)

    The report provides practical information needed for evaluating the radiation dose to the general public and workers caused by materials containing elevated levels of natural radionuclides. The report presents criteria, exposure scenarios and calculations used to assess dose with respect to the safety requirements set for construction materials in accordance with the Finnish Radiation Act. A method for calculating external gamma exposure from building materials is presented in detail. The results for most typical cases are given as specific dose rates in table form to enable doses to be assessed without computer calculation. A number of such dose assessments is presented, as is the corresponding computer code. Practical investigation levels for the radioactivity of materials are defined. (23 refs.)

  5. Dose dependent rearrangement of cellular membranes induced by ionizing radiation

    International Nuclear Information System (INIS)

    The radiation-induced effects at dose rate of 0.35 Gy/min (in vivo) and of ultra-low doses (in vitro) on the cell membranes structural state were shown. The modifications of the membrane protein and lipid components and their dynamic state were revealed at experimental irradiation conditions by fluorescent probe analysis. The principal component analysis of the research data indicates the dose-dependent decrease of plasma membrane structural orderliness of the small intestine enterocytes with the increase of the ionizing irradiation acute dose of 0.5, 1.0, 2.0, 3.0 Gy at dose rate of 0.35 Gy/min. The complex response of the biological structure - the erythrocytes plasma membrane, on the ionizing radiation action at ultra-low doses that occurred through macromolecular structural rearrangements was also demonstrated. The features of the structural rearrangement of the cellular membranes depending on the ionizing radiation dose (dose rate) are found out

  6. Biological dosimetry of ionizing radiation in the high dose range

    International Nuclear Information System (INIS)

    The report reviews briefly methods of dose evaluation after exposure to high doses of ionizing radiation. Validation of two methods also is described: micronucleus (Mn) frequency estimation according Muller and Rode and premature chromosome condensation (PCC) combined with painting of 3 pairs of chromosomes in human lymphocytes. According to Muller and Rode, micronucleus frequency per binucleated cells with at least one Mn linearly increases with dose up to 15 Gy and is suitable end-point for biological dosimetry. These authors, however, examined cells from only one donor. The data reported below were obtained for 5 donors; they point to a considerable individual variation of thus measured response to irradiation. Due to the high degree of inter-donor variability, there is no possibility to apply this approach in biological dosimetry in the dose range 5 - 20 Gy gamma 60Co radiation. A linear response up to 10 Gy was observed only in the case of certain donors. In contrast, determination of the dose-effect relationship with the PCC method gave good results (small inter-individual variation, no plateau effect up to dose 10 Gy), so that with a calibration curve it could be used for dose estimation after exposure to doses up to 10 Gy of X or gamma 60Co radiation. (author)

  7. Human evidence on the shape of the dose-response curves for radiation carcinogenesis

    International Nuclear Information System (INIS)

    The carcinogenic effects of high levels of ionizing radiation are better understood than those of any other environmental agent. However, the somatic risk from low doses is highly disputed. The uncertainties stem from the fact that a direct estimation of small risks requires impracticably large samples. Therefore, risk estimates for low doses have to be derived indirectly by extrapolation from high exposure data and are heavily dependent on assumptions about the form of the dose-response curve. Although radiobiological theories tested on in vitro systems predict a quadratic term in the dose-response equation which should, at least for sparsely ionizing radiation, dominate the shape of the curve, the epidemiological data available cannot exclude the possibility of a pure linear relationship. In some cases, apparent thresholds may result from latent periods inversely related to dose. Besides depending on the quality of the radiation, the shape seems also to differ with the type of cancer induced. Studies on uranium miners, atomic bomb survivors and on irradiated patients are reviewed with emphasis on the shape of the dose-response. The credibility of the most publicized reports claiming a large cancer risk from low levels of radiation is assessed. The feasibility of a new study in an area of high natural background is explored. Finally, the influence of the uncertainties concerning the effect of low level radiation on future exposure limits set by regulatory bodies is discussed. (Auth.)

  8. Phosphoproteomics profiling of human skin fibroblast cells reveals pathways and proteins affected by low doses of ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Feng Yang

    Full Text Available BACKGROUND: High doses of ionizing radiation result in biological damage; however, the precise relationships between long-term health effects, including cancer, and low-dose exposures remain poorly understood and are currently extrapolated using high-dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose-dependent responses to radiation. PRINCIPAL FINDINGS: We have identified 7117 unique phosphopeptides (2566 phosphoproteins from control and irradiated (2 and 50 cGy primary human skin fibroblasts 1 h post-exposure. Semi-quantitative label-free analyses were performed to identify phosphopeptides that are apparently altered by radiation exposure. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation-responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatic analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role for MAP kinase and protein kinase A (PKA signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. CONCLUSIONS: Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provide a basis for the systems-level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at different radiation doses and elucidate the impact of low-dose radiation exposure on human health.

  9. A Cosmic Microwave Background Radiation Polarimeter Using Superconducting Bearings

    CERN Document Server

    Hanany, S; Johnson, B; Jones, T; Hull, J R; Ma, K B

    2003-01-01

    Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured the coefficient of friction as a function of several parameters including temperature between 15 and 80 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm, and ambient pressure between 10^{-7} and 1 torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.

  10. Photosensitivity of murine skin greatly depends on the genetic background: clinically relevant dose as a new measure to replace minimal erythema dose in mouse studies.

    Science.gov (United States)

    Gyöngyösi, Nóra; Lőrincz, Kende; Keszeg, András; Haluszka, Dóra; Bánvölgyi, András; Tátrai, Erika; Kárpáti, Sarolta; Wikonkál, Norbert M

    2016-07-01

    Artificial UV irradiation of murine skin is a frequently used method for testing photosensitivity, study carcinogenesis and photoprotective effects of different compounds. However, doses of UV radiation and mouse strains used in experiments vary greatly. The genetic background of mice may influence the photosensitivity as melanin content, pigmentation and hair cycle parameters are dissimilar. Doses of UV are often expressed in relation to the minimal erythema dose (MED) that was not necessarily determined for the given strain. We set out to standardize the method of measuring photosensitivity in three commonly used mouse strains, C57BL/6N, Balb/c and SKH-1. We found that MED may not be determined for some strains as erythema development in mice with diverse genotypes differs greatly. We measured the oedema response in vivo and ex vivo by using OCT. Given the strain-specific variability of erythema, we introduced Clinically Relevant Dose (CRD) as a new term to replace MED in experiments, to describe the lowest dose that triggers a perceptible skin reaction in mice. Not only the CRD but the proportion of erythema and oedema were different in strains examined. C57BL/6N mice display skin reactions at the lowest UVB dose, while SKH-1 hairless mice show changes, mostly oedema, after higher doses of UVB. The cellular composition and skin thickness were examined by histopathology. IL-1beta and IL-6 levels in skin correlated with the increasing doses of UVB. Despite the variations in the degree of erythema and oedema, no major differences in cytokine expressions were seen among various strains of mice. PMID:26910301

  11. Environmental gamma monitoring in high background radiation areas of Orissa using CaSO4:Dy TL dosimeters

    International Nuclear Information System (INIS)

    Naturally occurring radionuclides are the major contributor to the total effective dose of ionizing radiation received by the population. In India, there are quite a few monazite sand bearing placer deposits causing high background radiation along its long coastline. Chatrapur, Orissa is one of the high background areas of India. The beach sand of this area contains natural mineral Monazite abundantly. Maximum and minimum dose were found 1202. 1 μGy in spring and 483.8 μGy in monsoon at Port School and Gopalpur respectively. In spring, summer, monsoon and winter season the dose ranges were observed 1202.1-520.3, 1154.7-503.6, 1066.3-483.8 and 1141.7-508.5 μG respectively. (author)

  12. Biological impact of high-dose and dose-rate radiation exposure

    International Nuclear Information System (INIS)

    Experimental anti-radiation vaccine is a power tool of immune - prophylaxis of the acute radiation disease. Existing principles of treatment of the acute radiation dis ease are based on a correction of developing patho-physiological and biochemical processes within the first days after irradiation. Protection from radiation is built on the general principles of immunology and has two main forms - active and passive immunization. Active immunization by the essential radiation toxins of specific radiation determinant (S.D.R.) group allows significantly reduce the lethality and increase duration of life among animals that are irradiated by lethal and sub-lethal doses of gamma radiation.The radiation toxins of S.D.R. group have antigenic properties that are specific for different forms of acute radiation disease. Development of the specific and active immune reaction after intramuscular injection of radiation toxins allows optimize a manifestation of a clinical picture and stabilize laboratory parameters of the acute radiation syndromes. Passive immunization by the anti-radiation serum or preparations of immune-globulins gives a manifestation of the radioprotection effects immediately after this kind of preparation are injected into organisms of mammals. Providing passive immunization by preparations of anti-radiations immune-globulins is possible in different periods of time after radiation. Providing active immunization by preparations of S.D.R. group is possible only to achieve a prophylaxis goal and form the protection effects that start to work in 18 - 35 days after an injection of biological active S.D.R. substance has been administrated. However active and passive immunizations by essential anti-radiation toxins and preparations of gamma-globulins extracted from a hyper-immune serum of a horse have significantly different medical prescriptions for application and depend on many factors like a type of radiation, a power of radiation, absorption doses, a time of

  13. Biological impact of high-dose and dose-rate radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Maliev, V.; Popov, D. [Russian Academy of Science, Vladicaucas (Russian Federation); Jones, J.; Gonda, S. [NASA -Johnson Space Center, Houston (United States); Prasad, K.; Viliam, C.; Haase, G. [Antioxida nt Research Institute, Premier Micronutrient Corporation, Novato (United States); Kirchin, V. [Moscow State Veterinary and Biotechnology Acade my, Moscow (Russian Federation); Rachael, C. [University Space Research Association, Colorado (United States)

    2006-07-01

    Experimental anti-radiation vaccine is a power tool of immune - prophylaxis of the acute radiation disease. Existing principles of treatment of the acute radiation dis ease are based on a correction of developing patho-physiological and biochemical processes within the first days after irradiation. Protection from radiation is built on the general principles of immunology and has two main forms - active and passive immunization. Active immunization by the essential radiation toxins of specific radiation determinant (S.D.R.) group allows significantly reduce the lethality and increase duration of life among animals that are irradiated by lethal and sub-lethal doses of gamma radiation.The radiation toxins of S.D.R. group have antigenic properties that are specific for different forms of acute radiation disease. Development of the specific and active immune reaction after intramuscular injection of radiation toxins allows optimize a manifestation of a clinical picture and stabilize laboratory parameters of the acute radiation syndromes. Passive immunization by the anti-radiation serum or preparations of immune-globulins gives a manifestation of the radioprotection effects immediately after this kind of preparation are injected into organisms of mammals. Providing passive immunization by preparations of anti-radiations immune-globulins is possible in different periods of time after radiation. Providing active immunization by preparations of S.D.R. group is possible only to achieve a prophylaxis goal and form the protection effects that start to work in 18 - 35 days after an injection of biological active S.D.R. substance has been administrated. However active and passive immunizations by essential anti-radiation toxins and preparations of gamma-globulins extracted from a hyper-immune serum of a horse have significantly different medical prescriptions for application and depend on many factors like a type of radiation, a power of radiation, absorption doses, a time of

  14. Photon and neutron dose evaluation in experimental hall of Indus-1 synchrotron radiation source

    International Nuclear Information System (INIS)

    Radiation measurement in Indus-1 experimental hall and Control Room area was performed for evaluating the photon and neutron dose rates during various operating conditions. The measurements were carried out using VICTOREEN 451 P and LUDLUM Model 2363 survey meter for photon and neutron dose rate measurement respectively. From the measurements, it was seen that during Indus-1 injection, maximum photon dose rate of 410 μSv/h and maximum neutron dose rate of 15.9 μSv/h was observed at one of the hot spots (front of pre-mirror, Beam Line-1). At experimental station of the beam lines, the neutron dose rates observed were in the range 1.0 - 3.4 μSv/h whereas the photon dose rates were up to 0.9 μSv/h. During Indus-1 storage condition, the radiation levels were near background levels except at one of the hot spots (pre-mirror, BL-4) where photon and neutron dose rates observed were 6.3 μSv/h and 45.1 μSv/h respectively. During Indus-2 injection neutron dose rates ranging from background to 3.3 μSv/h were observed in the sitting area at experimental station whereas photon dose rate was noticed up to 0.4 μSv/h. For the control room area, neutron dose rates up to a maximum of 3 μSv/h were observed during Indus-1 injection only. During other operation modes, dose rates in control room are of background level. Details of the measurements and results are presented in the paper. (author)

  15. Radiation doses to the staff of a nuclear cardiology department

    International Nuclear Information System (INIS)

    The last years, new radiopharmaceuticals are used in a Nuclear Medicine (NM) Department. Nowadays, Single Photon Emission Computed Tomography (SPECT) is a method of routine imaging, a fact that has required increased levels of radioactivity in certain patient examinations. The staff that is more likely to receive the greatest radiation dose in a NM Department is the technologist who deals with performance of patient examination and injection of radioactive material and the nurse who is caring for the patients visiting the Department some of which being totally helpless. The fact that each NM Dept possesses equipment with certain specifications, deals with various kind of patients, has specific design and radiation protection measures which can differ from other NM Depts and uses various examination protocols, makes essential the need to investigate the radiation doses received by each member of the staff, so as to continuously monitor doses and take protective measures if required, control less experienced staff and ensure that radiation dose levels are kept as low as possible at all times. The purpose of the current study was to evaluate radiation dose to the nuclear cardiology department staff by thermoluminescent dosemeters (TLDs) placed on the the skin at thyroid and abdominal region as well as evaluating protection measures taken currently in the Dept

  16. A method of estimating fetal dose during brain radiation therapy

    International Nuclear Information System (INIS)

    Purpose: To develop a simple method of estimating fetal dose during brain radiation therapy. Methods and Materials: An anthropomorphic phantom was modified to simulate pregnancy at 12 and 24 weeks of gestation. Fetal dose measurements were carried out using thermoluminescent dosimeters. Brain radiation therapy was performed with two lateral and opposed fields using 6 MV photons. Three sheets of lead, 5.1-cm-thick, were positioned over the phantom's abdomen to reduce fetal exposure. Linear and nonlinear regression analysis was used to investigate the dependence of radiation dose to an unshielded and/or shielded fetus upon field size and distance from field isocenter. Results: Formulas describing the exponential decrease of radiation dose to an unshielded and/or shielded fetus with distance from the field isocenter are presented. All fitted parameters of the above formulas can be easily derived using a set of graphs showing their correlation with field size. Conclusion: This study describes a method of estimating fetal dose during brain radiotherapy, accounting for the effects of gestational age, field size and distance from field isocenter. Accurate knowledge of absorbed dose to the fetus before treatment course allows for the selection of the proper irradiation technique in order to achieve the maximum patient benefit with the least risk to the fetus

  17. Cosmic background radiation spectral distortion and radiative decays of relic neutral particles

    International Nuclear Information System (INIS)

    The recently observed excess of photons on a short wavelength side of the peak of a cosmic background radiation spectrum can be described by radiative decays of relic neutral particles. The lifetime and mass of a decaying particle must satisfy the following conditions: 2x109 s14 s, 0.4 eV-9-8x10-8) μb, and the interaction of new particles with the usual matter must be rather strong. The generalization of the standard SU(3)xSU(2)xU(1) model is presented which includes new particles with the desired properties. 18 refs.; 3 figs.; 2 tabs

  18. Techniques and radiation dose in CT examinations of adult patients

    International Nuclear Information System (INIS)

    The use of CT in medical diagnosis delivers radiation dose to patients that are higher than those from other radiological procedures. Lake of optimized protocols could be an additional source of increased dose. The aim of this study was to measure radiation doses in CT examination of the adults in three Sudanese hospitals. Details were obtained from approximately 160 CT examination carried out in 3 hospitals (3 CT scanners). Effective dose was calculated for each examination using CT dose indices. exposure related parameters and CT D1- to- effective dose conversion factors. CT air kerma index (CT D1) and dose length products (DLP) determined were below the established international reference dose levels. The mean effective doses in this study for the head, chest, and abdomen are 0.82, 3.7 and 5.4 mGy respectively. These values were observed that the effective dose per examination was lower in Sudan than in other countries. The report of a CT survey done in these centers indicates that the mean DLP values for adult patients were ranged from 272-460 mGy cm (head) 195-995 mGy cm (chest), 270-459 mGy cm (abdomen). There are a number of observed parameters that greatly need optimization, such as minimize the scan length, without missing any vital anatomical regions, modulation of exposure parameters (kV, mA, exposure time, and slice thickness) based on patient size and age. Another possible method is through use of contrast media only to optimize diagnostic yield. The last possible method is the use of radio protective materials for protection however, in order to achieve the above optimization strategies: there is great demand to educate CT personnel on the effects of scan parameter settings on radiation dose to patients and image quality required for accurate diagnosis. (Author)

  19. Reduction of patient radiation dose in Spiral CT scan

    International Nuclear Information System (INIS)

    To optimize patient radiation dose in Spiral CT scan of dento-maxillo-facial region by measuring the absorbed dose in the phantom and to evaluate reliability of dose estimation methods using CTDI (CT Dose Index, FDA, USA). Spiral CT scanning with 'pitchs' (ratio of table speed to slice thickness per rotation) more than 1 was used for dose measurements. The dose was measured using a human phantom (Alderson Research Laboratories, USA) in the CT scan with a 3rd generation CT scanner of Somatom Plus (Siemens, Germany) for bone imaging. CTDI for this CT scanner were 9.2 mGy/100 mA at the center in an acrylic resin phantom with diameter of 16 cm and 8.5 mGy/100 mA at 1 cm depth from the phantom surface. X-ray tube voltage of 120 kV and tube current of 85 mA was used. Slice thickness was varied from 1 to 3 mm and table speed per rotation was also varied from 1 to 5 mm per rotation. X-Omat-V (Eastman Kodak, USA) films and TLD (Thermo-Luminescent-Dosimetry) dosimeters of the type of MSO-S (Kyokko, Japan) were used in the dosimetry. Patients radiation dose reduced with increasing the pitch of SPIRAL scan. Measured dose was uniformly distributed and well corresponded to the dose calculated using CTDI. However, measured doses on scanning with 1 mm slice thickness were always higher than those with 2 to 5 mm slice thickness. The lowest radiation dose was obtained with scanning with 2 mm slice thickness and table speed of 4 mm per rotation which give the dose of about 4 mGy per one CT examination in the imaged tissues. The highest dose per one CT examination was measured in 'dental CT' for the mandibular region with 1 mm slice thickness and table speed of 1 mm per rotation which gave 12 mGy by film dosimetry and 9 mGy by TLD dosimetry. SPIRAL scan with pitch more than 1 was effective for reduction of patient radiation dose without reducing the image quality. CTDI was also useful to estimate the dose except scans with 1 mm slice thickness. (author)

  20. Social economical and psychological considerations in conveying potential radiation risks from high level natural background radiation to the residents of Ramsar, Iran

    International Nuclear Information System (INIS)

    X-rays and radioactivity were discovered more than 100 years ago but the need for protection against very low doses of ionizing radiation and especially different levels of natural radiation is still among the most controversial matters in radiobiology and radiation protection. According to formal reports, some areas in Ramsar, a city in northern Iran, are the inhabited areas with the highest levels of natural radiation studied so far. A population of about 2000 is exposed to average annual radiation levels of 10.2 mGy y''-1 and the highest recorded external gamma dose rates are about 130 mGy y''-1. We have previously shown that in high background radiation areas (HBRAs), cultured human lymphocytes of the inhabitants whose cumulative radiation doses were as much as 170 times more than those of a control area when subjected to 1.5 Gy challenge dose,were significantly more radioresistant compared to the residents of the control area (Mortazavi et al. 2002a,b, Mortazavi and Karam 2002, Ghiassi-Najed et al. 2002). The people who live in these areas are usually unaware of the high levels of natural radiation in their environment. Studies performed on the residents of these areas have indicated that the effective dose of the inhabitants, in some cases, is much higher than the dose limits for occupational irradiation. Considering recent policies of ICRP regarding suggesting dose limits for exposure to natural sources of ionizing including radon, it seems that the inhabitants should become familiar with the possible risks of the exposure to high levels of ionizing radiation. They should also realize that studies performed over the past years have indicated no detrimental effect. On the other hand, according to ICRP suggestions and considering the experiences in other countries, especially evacuation of the residents of contaminated areas after Chernobyl accident, setting any radiation protection regulation for the inhabitants without considering social, economic and

  1. Phosphoproteomics profiling of human skin fibroblast cells reveals pathways and proteins affected by low doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Feng; Waters, Katrina M.; Miller, John H.; Gritsenko, Marina A.; Zhao, Rui; Du, Xiuxia; Livesay, Eric A.; Purvine, Samuel O.; Monroe, Matthew E.; Wang, Yingchun; Camp, David G.; Smith, Richard D.; Stenoien, David L.

    2010-11-30

    Background: High doses of ionizing radiation result in biological damage, however the precise relationships between long term health effects, including cancer, and low dose exposures remain poorly understood and are currently extrapolated using high dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose dependent responses to radiation. Principle Findings: We have identified 6845 unique phosphopeptides (2566 phosphoproteins) from control and irradiated (2 and 50 cGy) primary human skin fibroblasts one hour post-exposure. Dual statistical analyses based on spectral counts and peak intensities identified 287 phosphopeptides (from 231 proteins) and 244 phosphopeptides (from 182 proteins) that varied significantly following exposure to 2 and 50 cGy respectively. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatics analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role of MAP kinase and protein kinase A (PKA) signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. Conlcusions: Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provides a basis for the systems level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at

  2. Vertical distribution of radiation dose rates in the water of a brackish lake in Aomori Prefecture, Japan

    International Nuclear Information System (INIS)

    Seasonal radiation dose rates were measured with glass dosemeters housed in watertight cases at various depths in the water of Lake Obuchi, a brackish lake in Aomori Prefecture, Japan, during fiscal years 2011-2013 to assess the background external radiation dose to aquatic biota in the lake. The mean radiation dose in the surface water of the lake was found to be 27 nGy h-1, which is almost the same as the absorption dose rate due to cosmic ray reported in the literature. Radiation dose rates decreased exponentially with water depth down to a depth of 1 m above the bottom sediment. In the water near the sediment, the dose rate increased with depth owing to the emission of γ-rays from natural radionuclides in the sediment. (authors)

  3. Excess relative risk of solid cancer mortality after prolonged exposure to naturally occurring high background radiation in Yangjiang, China

    Energy Technology Data Exchange (ETDEWEB)

    Sun Quanfu; Tao Zufan [Ministry of Health, Beijing (China). Lab. of Industrial Hygiene; Akiba, Suminori (and others)

    2000-10-01

    A study was made on cancer mortality in the high-background radiation areas of Yangjiang, China. Based on hamlet-specific environmental doses and sex- and age-specific occupancy factors, cumulative doses were calculated for each subject. In this article, we describe how the indirect estimation was made on individual dose and the methodology used to estimate radiation risk. Then, assuming a linear dose response relationship and using cancer mortality data for the period 1979-1995, we estimate the excess relative risk per Sievert for solid cancer to be -0.11 (95% CI, -0.67, 0.69). Also, we estimate the excess relative risks of four leading cancers in the study areas, i.e., cancers of the liver, nasopharynx, lung and stomach. In addition, we evaluate the effects of possible bias on our risk estimation. (author)

  4. Health Effects of Exposure to Low Dose of Radiation

    International Nuclear Information System (INIS)

    Human beings are exposed to natural radiation from external sources include radionuclides in the earth and cosmic radiation, and by internal radiation from radionuclides, mainly uranium and thorium series, incorporated into the body. Living systems have adapted to the natural levels of radiation and radioactivity. But some industrial practices involving natural resources enhance these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Biological effects of ionizing radiation are the outcomes of physical and chemical processes that occur immediately after the exposure, then followed by biological process in the body. These processes will involve successive changes in the molecular, cellular, tissue and whole organism levels. Any dose of radiation, no matter how small, may produce health effects since even a single ionizing event can result in DNA damage. The damage to DNA in the nucleus is considered to be the main initiating event by which radiation causes damage to cells that results in the development of cancer and hereditary disease. It has also been indicated that cytogenetic damage can occur in cells that receive no direct radiation exposure, known as bystander effects. This paper reviews health risks of low dose radiation exposure to human body causing stochastic effects, i.e. cancer induction in somatic cells and hereditary disease in genetic cells. (author)

  5. Low-level radiation doses - a hazard to health?

    International Nuclear Information System (INIS)

    The health hazard induced by low radiation doses can be understood only if we gain an understanding of the fate of the radiation-sensitive structural element within the biological system which it undergoes in the radiation field, and its significance for the total system. In the low-level dose range, single absorption events occur in individual cells as sensitive elements; such single events cause an acute, temporary thymidine kinase inhibition. During this reaction, the affected cell reveals to be resistant to a second event. These observations question the generality of a linear realation between dose and biological effect. We may even have to consider a beneficial effect of single absorption events in the affected cells. (orig./HP)

  6. Local dose enhancement in radiation therapy: Monte Carlo simulation study

    International Nuclear Information System (INIS)

    The development of nanotechnology has boosted the use of nanoparticles in radiation therapy in order to achieve greater therapeutic ratio between tumor and healthy tissues. Gold has been shown to be most suitable to this task due to the high biocompatibility and high atomic number, which contributes to a better in vivo distribution and for the local energy deposition. As a result, this study proposes to study, nanoparticle in the tumor cell. At a range of 11 nm from the nanoparticle surface, results have shown an absorbed dose 141 times higher for the medium with the gold nanoparticle compared to the water for an incident energy spectrum with maximum photon energy of 50 keV. It was also noted that when only scattered radiation is interacting with the gold nanoparticles, the dose was 134 times higher compared to enhanced local dose that remained significant even for scattered radiation. (author)

  7. Dose Definition and Physical Dose Evaluation for the Human Body in External Radiation Accidents

    International Nuclear Information System (INIS)

    For the bone marrow type of radiation sickness, it is possible to describe the injury to whole-body haematopoietic tissue using stem cell dose. In the case of highly non-uniform exposure, an extra-high local dose to certain parts of the body or absorbed dose to critical organs should be additionally described. To obtain objective dosimetric data from objects carried by the irradiated victims, the watch is an easily available accident dosemeter. Watch rubies can be used as thermoluminescence dosemeters, and the watch glass can be used in electron spin resonance dose measurement. (author)

  8. Radiation-induced stress effects following low dose exposure

    International Nuclear Information System (INIS)

    Complete text of publication follows. Recent advances in our understanding of effects of radiation on living cells suggest that fundamentally different mechanisms are operating at low doses compared with high doses. Also, acute low doses appear to involve different response mechanisms compared with chronic low doses. Both genomic instability and so called 'bystander effects' show many similarities with well known cellular responses to oxidative stress. These predominate following low dose exposures and are maximally expressed at doses as low as 5mGy. At the biological level this is not surprising. Chemical toxicity has been known for many years to show these patterns of dose response. Cell signaling and coordinated stress mechanisms appear to dominate acute low dose exposure to chemicals. Adaptation to chemical exposures is also well documented although mechanisms of adaptive responses are less clear. In the radiation field adaptive responses also become important when low doses are protracted or fractionated. Recent data from our group concerning bystander effects following multiple low dose exposures suggest that adaptive responses can be induced in cells which only receive signals from irradiated neighbours. We have data showing delayed and bystander effects in humans, rodents 3 fish species and in prawns following in vitro and/or in vivo irradiation of haematopoietic tissues and, from the aquatic groups, gill and skin/fin tissue. Bystander signals induced by radiation can be communicated from fish to fish in vivo and are detectable as early as the eyed egg stage, i.e. as soon as tissue starts to develop. Using proteomic approaches we have determined that the bystander and the direct irradiation proteomes are different. The former show significant upregulation of 5 proteins with anti-oxidant, regenerative and restorative functions while the direct radiation proteome has 2 upregulated proteins both involved in proliferation. These data have implications for

  9. Uncertainty of dose measurement in radiation processing

    DEFF Research Database (Denmark)

    Miller, A.

    1996-01-01

    The major standard organizations of the world have addressed the issue of reporting uncertainties in measurement reports and certificates. There is, however, still some ambiguity in the minds of many people who try to implement the recommendations in real life. This paper is a contribution...... that contribute to the observable uncertainty of repeated measurements and those that do not. Examples of the use of these principles are presented in the paper....... to the running debate and presents the author's view, which is based upon experience in radiation processing dosimetry. The origin of all uncertainty components must be identified and can be classified according to Type A and Type B, but it is equally important to separate the uncertainty components into those...

  10. Early radiation dose-response in lung: an ultrastructural study

    International Nuclear Information System (INIS)

    A systematic fine-structural study of dog lungs was undertaken to ascertain the radiation dose response in the lungs of large animals. The capillary endothelium appeared to be the initial site of the post-irradiation pulmonary damage. This subpheural response included diffuse septal thickening, fibrosis, edema, and reduced alveolar lumina. The deep parenchymal response involved perivascular fibrosis, which was associated with perivascular hyperplasia of Type II pneumocytes, increased number and sizes of lamellar bodies, increased production and release of lamellar surfactant. No changes of alveolar luminar size were noted. The most significant changes were observed in those dose zones exposed to greater than 2400 rad, suggesting the possibility of an identifiable dose-response relationship. Early detection of radiation pneumonitis by electron microscopy is demonstrated, and qualitative and quantitative correlation of injury with both postirradiation time and dose is presented

  11. Radiation dose to physicians’ eye lens during interventional radiology

    Science.gov (United States)

    Bahruddin, N. A.; Hashim, S.; Karim, M. K. A.; Sabarudin, A.; Ang, W. C.; Salehhon, N.; Bakar, K. A.

    2016-03-01

    The demand of interventional radiology has increased, leading to significant risk of radiation where eye lens dose assessment becomes a major concern. In this study, we investigate physicians' eye lens doses during interventional procedures. Measurement were made using TLD-100 (LiF: Mg, Ti) dosimeters and was recorded in equivalent dose at a depth of 0.07 mm, Hp(0.07). Annual Hp(0.07) and annual effective dose were estimated using workload estimation for a year and Von Boetticher algorithm. Our results showed the mean Hp(0.07) dose of 0.33 mSv and 0.20 mSv for left and right eye lens respectively. The highest estimated annual eye lens dose was 29.33 mSv per year, recorded on left eye lens during fistulogram procedure. Five physicians had exceeded 20 mSv dose limit as recommended by international commission of radiological protection (ICRP). It is suggested that frequent training and education on occupational radiation exposure are necessary to increase knowledge and awareness of the physicians’ thus reducing dose during the interventional procedure.

  12. Low dose ionizing radiation exposure and cardiovascular disease mortality: cohort study based on Canadian national dose registry of radiation workers

    International Nuclear Information System (INIS)

    The purpose of our study was to assess the risk of cardiovascular disease (CVD) mortality in a Canadian cohort of 337 397 individuals (169 256 men and 168 141 women) occupationally exposed to ionizing radiation and included in the National Dose Registry (NDR) of Canada. Material and Methods: Exposure to high doses of ionizing radiation, such as those received during radiotherapy, leads to increased risk of cardiovascular diseases. The emerging evidence of excess risk of CVDs after exposure to doses well below those previously considered as safe warrants epidemiological studies of populations exposed to low levels of ionizing radiation. In the present study, the cohort consisted of employees at nuclear power stations (nuclear workers) as well as medical, dental and industrial workers. The mean whole body radiation dose was 8.6 mSv for men and 1.2 mSv for women. Results: During the study period (1951 - 1995), as many as 3 533 deaths from cardiovascular diseases have been identified (3 018 among men and 515 among women). In the cohort, CVD mortality was significantly lower than in the general population of Canada. The cohort showed a significant dose response both among men and women. Risk estimates of CVD mortality in the NDR cohort, when expressed as excess relative risk per unit dose, were higher than those in most other occupational cohorts and higher than in the studies of Japanese atomic bomb survivors. Conclusions: The study has demonstrated a strong positive association between radiation dose and the risk of CVD mortality. Caution needs to be exercised when interpreting these results, due to the potential bias introduced by dosimetry uncertainties, the possible record linkage errors, and especially by the lack of adjustment for non-radiation risk factors. (authors)

  13. Cytogenetic effects of low ionising radiation doses and biological dosimetry

    OpenAIRE

    Gricienė, Birutė

    2010-01-01

    The intensive use of ionising radiation (IR) sources and development of IR technology is related to increased exposure and adverse health risk to workers and public. The unstable chromosome aberration analysis in the group of nuclear energy workers (N=84) has shown that doses below annual dose limit (50 mSv) can induce chromosome aberrations in human peripheral blood lymphocytes. Significantly higher frequencies of the total chromosome aberrations were determened in the study group when compa...

  14. Radiation impact on spaceborne optics: the dose coefficients approach

    Science.gov (United States)

    Fruit, Michel; Gusarov, Andrei I.; Doyle, Dominic B.; Ulbrich, Gerd J.

    1999-12-01

    During the past 30 years of development of Space optical instrumentation for such missions as METEOSAT, SPOT, HIPPARCOS and SILEX with ESA and CNES, Matra Marcon Space (MMS) has conducted extensive studies on the behavior of optical materials under irradiation such as quantifying transmission losses in optical glasses and measuring the dimensional stability of Zerodur as a substrate for mirror applications. Thanks to this background experience, MMS, in cooperation with SCK-CEN, is conducting a study (under ESA sponsorship) to define the approach for the gathering of a comprehensive data base to quantify these effects through the use of linear sensitivity coefficients (so-called `Dose Coefficients'). This follows recent investigations which have shown that the space radiation environment can affect not only transmission but also other characteristics of refractive optical materials in both classical and Cerium doped glasses. A number of selected examples from specific MMS studies will first be shown. Then, the actual approach being taken to this problem, on the basis of already obtained results from preliminary experiments performed by ESTEC, will be presented.

  15. Management of pediatric radiation dose using Agfa computed radiography

    Energy Technology Data Exchange (ETDEWEB)

    Schaetzing, R. [Agfa Corp., Greenville, SC (United States)

    2004-10-01

    Radiation dose to patients and its management have become important considerations in modern radiographic imaging procedures, but they acquire particular significance in the imaging of children. Because of their longer life expectancy, children exposed to radiation are thought to have a significantly increased risk of radiation-related late sequelae compared to adults first exposed to radiation later in life. Therefore, current clinical thinking dictates that dose in pediatric radiography be minimized, while simultaneously ensuring sufficient diagnostic information in the image, and reducing the need for repeat exposures. Dose management obviously starts with characterization and control of the exposure technique. However, it extends farther through the imaging chain to the acquisition system, and even to the image processing techniques used to optimize acquired images for display. Further, other factors, such as quality control procedures and the ability to handle special pediatric procedures, like scoliosis exams, also come into play. The need for dose management in modern radiography systems has spawned a variety of different solutions, some of which are similar across different manufacturers, and some of which are unique. This paper covers the techniques used in Agfa Computed Radiography (CR) systems to manage dose in a pediatric environment. (orig.)

  16. Update on radiation safety and dose reduction in pediatric neuroradiology

    International Nuclear Information System (INIS)

    The number of medical X-ray imaging procedures is growing exponentially across the globe. Even though the overall benefit from medical X-ray imaging procedures far outweighs any associated risks, it is crucial to take all necessary steps to minimize radiation risks to children without jeopardizing image quality. Among the X-ray imaging studies, except for interventional fluoroscopy procedures, CT studies constitute higher dose and therefore draw considerable scrutiny. A number of technological advances have provided ways for better and safer CT imaging. This article provides an update on the radiation safety of patients and staff and discusses dose optimization in medical X-ray imaging within pediatric neuroradiology. (orig.)

  17. Update on radiation safety and dose reduction in pediatric neuroradiology

    Energy Technology Data Exchange (ETDEWEB)

    Mahesh, Mahadevappa [Johns Hopkins University School of Medicine, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States)

    2015-09-15

    The number of medical X-ray imaging procedures is growing exponentially across the globe. Even though the overall benefit from medical X-ray imaging procedures far outweighs any associated risks, it is crucial to take all necessary steps to minimize radiation risks to children without jeopardizing image quality. Among the X-ray imaging studies, except for interventional fluoroscopy procedures, CT studies constitute higher dose and therefore draw considerable scrutiny. A number of technological advances have provided ways for better and safer CT imaging. This article provides an update on the radiation safety of patients and staff and discusses dose optimization in medical X-ray imaging within pediatric neuroradiology. (orig.)

  18. Radiation dose evaluation during X-ray examinations in human medicine, dentistry, veterinary medicine and border controls using ionizing radiation

    International Nuclear Information System (INIS)

    The report on radiation dose evaluation during X-ray examinations includes the following chapters: (1) Scope of the project. (2) Measuring instruments. (3) Part I: Radiation dose evaluation during X-ray examinations in human medicine, dentistry, veterinary medicine. (4) Radiation dose evaluation during X-ray examinations during border controls using ionizing radiation. (5) Summary of results.

  19. Measurement of radiation dose in paediatric micturating cystourethrography

    International Nuclear Information System (INIS)

    Paediatrics and children have been recognized that they have a higher risk of developing cancer from the radiation than adults. Therefor, increased attention has been directed towards the dose to the patients. Micturating Cystourethrography (MCU) is a commonly use ed fluoroscopic procedure in children and commonly used to detect the vesicoureteric reflux (VUR) and show urethral and bladder and abnormalities. This study aims to measure the pediatric patients undergoing MCU. The study was carried out in two hospitals in Khartoum. The entrance surface dose (ESD) was determined determined by indirect method for 45 children. Furthermore, the mean ESD, sd and range resulting from MCU procedures has been estimated to be 0.7±.5 (0.2-2.5) mGy for the total patient population. The radiation dose to the patients is well within established safety limits, in the light of the current practice. The radiation dose results of this study are appropriate for adoption as the local initial dose reference level (DRL) value for this technique. The data presented in this study showed our doses to be approximately 50% lower than the lower mean values presented in the literature.(Author)

  20. Sensors of absorbed dose of ionizing radiation based on mosfet

    Directory of Open Access Journals (Sweden)

    Perevertaylo V. L.

    2010-10-01

    Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  1. Calibration of high-dose radiation facilities (Handbook)

    International Nuclear Information System (INIS)

    In India at present several high intensity radiation sources are used. There are 135 teletheraphy machines and 65 high intensity cobalt-60 sources in the form of gamma chambers (2.5 Ci) and PANBIT (50 Ci). Several food irradiation facilities and a medical sterilization plant ISOMED are also in operation. The application of these high intensity sources involve a wide variation of dose from 10 Gy to 100 kGy. Accurate and reproducible radiation dosimetry is essential in the use of these sources. This handbook is especially compiled for calibration of high-dose radiation facilities. The first few chapters discuss such topics as interaction of radiation with matter, radiation chemistry, radiation processing, commonly used high intensity radiation sources and their special features, radiation units and dosimetry principles. In the chapters which follow, chemical dosimeters are discussed in detail. This discussion covers Fricke dosimeter, FBX dosimeter, ceric sulphate dosimeter, free radical dosimetry, coloured indicators for irrdiation verification. A final chapter is devoted to practical hints to be followed in calibration work. (author)

  2. Effect of staff training on radiation dose in pediatric CT

    Energy Technology Data Exchange (ETDEWEB)

    Hojreh, Azadeh, E-mail: azadeh.hojreh@meduniwien.ac.at [Medical University of Vienna, Department of Biological Imaging and Image-guided Therapy, Division of General and Paediatric Radiology, Waehringer Guertel 18–20, A-1090 Vienna (Austria); Weber, Michael, E-mail: michael.Weber@Meduniwien.Ac.At [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of General and Paediatric Radiology, Waehringer Guertel 18–20, A-1090 Vienna (Austria); Homolka, Peter, E-mail: peter.Homolka@Meduniwien.Ac.At [Medical University of Vienna, Centre for Medical Physics and Biomedical Engineering, Waehringer Guertel 18–20, A-1090 Vienna (Austria)

    2015-08-15

    Highlights: • Pediatric patient CT doses were compared before and after staff training. • Staff training increasing dose awareness resulted in patient dose reduction. • Application of DRL reduced number of CT's with unusually high doses. • Continuous education and training are effective regarding dose optimization. - Abstract: Objective: To evaluate the efficacy of staff training on radiation doses applied in pediatric CT scans. Methods: Pediatric patient doses from five CT scanners before (1426 scans) and after staff training (2566 scans) were compared statistically. Examinations included cranial CT (CCT), thoracic, abdomen–pelvis, and trunk scans. Dose length products (DLPs) per series were extracted from CT dose reports archived in the PACS. Results: A pooled analysis of non-traumatic scans revealed a statistically significant reduction in the dose for cranial, thoracic, and abdomen/pelvis scans (p < 0.01). This trend could be demonstrated also for trunk scans, however, significance could not be established due to low patient frequencies (p > 0.05). The percentage of scans performed with DLPs exceeding the German DRLs was reduced from 41% to 7% (CCT), 19% to 5% (thorax-CT), from 9% to zero (abdominal–pelvis CT), and 26% to zero (trunk; DRL taken as summed DRLs for thorax plus abdomen–pelvis, reduced by 20% accounting for overlap). Comparison with Austrian DRLs – available only for CCT and thorax CT – showed a reduction from 21% to 3% (CCT), and 15 to 2% (thorax CT). Conclusions: Staff training together with application of DRLs provide an efficient approach for optimizing radiation dose in pediatric CT practice.

  3. Effect of staff training on radiation dose in pediatric CT

    International Nuclear Information System (INIS)

    Highlights: • Pediatric patient CT doses were compared before and after staff training. • Staff training increasing dose awareness resulted in patient dose reduction. • Application of DRL reduced number of CT's with unusually high doses. • Continuous education and training are effective regarding dose optimization. - Abstract: Objective: To evaluate the efficacy of staff training on radiation doses applied in pediatric CT scans. Methods: Pediatric patient doses from five CT scanners before (1426 scans) and after staff training (2566 scans) were compared statistically. Examinations included cranial CT (CCT), thoracic, abdomen–pelvis, and trunk scans. Dose length products (DLPs) per series were extracted from CT dose reports archived in the PACS. Results: A pooled analysis of non-traumatic scans revealed a statistically significant reduction in the dose for cranial, thoracic, and abdomen/pelvis scans (p < 0.01). This trend could be demonstrated also for trunk scans, however, significance could not be established due to low patient frequencies (p > 0.05). The percentage of scans performed with DLPs exceeding the German DRLs was reduced from 41% to 7% (CCT), 19% to 5% (thorax-CT), from 9% to zero (abdominal–pelvis CT), and 26% to zero (trunk; DRL taken as summed DRLs for thorax plus abdomen–pelvis, reduced by 20% accounting for overlap). Comparison with Austrian DRLs – available only for CCT and thorax CT – showed a reduction from 21% to 3% (CCT), and 15 to 2% (thorax CT). Conclusions: Staff training together with application of DRLs provide an efficient approach for optimizing radiation dose in pediatric CT practice

  4. The relevance of radiation induced bystander effects for low dose radiation carcinogenic risk

    International Nuclear Information System (INIS)

    Full text: Where epidemiology studies lack the ability to prescribe radiation doses, customise sample sizes and replicate findings, radiobiology experiments provide greater flexibility to control experimental conditions. This control simplifies the process of answering questions concerning carcinogenic risk after low dose radiation exposures. However, the flexibility requires critical evaluation of radiobiology findings to ensure that the right questions are being asked, the experimental conditions are relevant to human exposure scenarios and that the data are cautiously interpreted in the context of the experimental model. In particular, low dose radiobiology phenomena such as adaptive responses, genomic instability and bystander effects need to be investigated thoroughly, with continual reference to the way these phenomena might occur in the real world. Low dose radiation induced bystander effects are of interest since their occurrence in vivo could complicate the shape of the radiation dose-response curve in the low dose range for a number of biological endpoints with subsequent effects on radiation-induced cancer risk. Conversely, radiation-induced abscopal effects implicate biological consequences of radiation exposure outside irradiated volumes, and complicate the notion of effective dose calculations. Achieving a consensus on the boundaries that distinguish the radiobiology phenomena of bystander and abscopal effects will aid progress towards understanding their relevance to in vivo radiation exposures. A proposed framework for discussing bystander effects and abscopal effects in their appropriate context will be outlined, with a discussion on the future investigation of radiation-induced bystander effects. Such frameworks can assist the integration of results from experimental radiobiology to risk evaluation and management practice. This research was funded by the Low Dose Radiation Research Program, BioI. and Environ. Research, US Dept. of Energy, Grant DE

  5. Assessment of Environmental Gamma Radiation Dose Rate in Ardabil and Sarein in 2009

    Directory of Open Access Journals (Sweden)

    M Alighadri

    2011-10-01

    Full Text Available Background and Objectives: Gamma rays, the most energetic photons within the any other wave in the electromagnetic spectrum, pose enough energy to form charged particles and adversely affect human health. Provided that the external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined, environmental gamma dose rate and corresponding annual effective dose were determined in the cities of Ardabil and Sar Ein.Materials and Methods: Outdoor environmental gamma dose rates were measured using an Ion Chamber Survey Meter in 48 selected locations (one in city center and the remaining in cardinal and ordinal directions in Ardabil and Sar Ein. Ten more locations were monitored along the hot springs effluent in Sar Ein. Measurements of gamma radiation dose rate were performed at 20 and 100 cm above the ground for a period of one hour.Results: Average outdoor environmental gamma dose rate were determined as 265, 219, and 208  for Ardabil, Sar Ein, and along the hot spring effluent, respectively. The annual affective dose for Ardabil and Sar Ein residents were estimated to be 1.45 and 1.39 mSv, respectively.Conclusion: Calculated annual effective dose of 1.49 and 1.35 are appreciably higher than the population weighted average exposure to environmental gamma radiation worldwide and that analysis of soil content to different radionuclide is suggested.

  6. Measurement and assessment of doses from external radiations required for revised radiation protection regulations

    International Nuclear Information System (INIS)

    Radiation protection regulations based on the 1990 recommendations of ICRP have been revised and will take effect from Apr., 2001. The major changes concerning on the measurement and assessment of doses from external radiations are as follows. (1) Personal dose equivalent and ambient dose equivalent stated in ICRP Publication 74 are introduced as quantities to be measured with personal dosimeters and survey instruments, respectively. (2) For multiple dosimetry for workers, the compartment weighting factors used for a realistic assessment of effective dose are markedly changed. In advance of the introduction of the new radiation protection regulations, the impacts on workplace and personal monitoring for external radiations by these revisions were investigated. The following results were obtained. (1) A new ambient dose equivalent to neutrons is higher with a factor of 1.2 than the old one for moderated fission neutron spectra. Therefore, neutron dose equivalent monitors for workplace monitoring at MOX fuel for facilities should be recalibrated for measurement of the new ambient dose equivalent. (2) Annual effective doses of workers were estimated by applying new calibration factors to readings of personal dosimeters, worn by workers. Differences between effective doses and effective dose equivalents are small for workers engaged in the fabrication process of MOX fuel. (author)

  7. The assessment of personal dose due to external radiation

    International Nuclear Information System (INIS)

    The fundamental basis of thermoluminescent dosimetry (TLD) is discussed and a number of considerations in the measurement of thermoluminescence described, with particular reference to CaSO4:Dy. The steps taken to convert a thermoluminescence measurement to an exposure and then an absorbed dose are outlined. The calculation of effective dose equivalents due to external exposure to γ-radiation in a number of situations commonly encountered in a uranium mine is discussed. Factors which may affect the accuracy of external dose assessments are described

  8. Characteristics of radiation dose rate distribution in living environment

    International Nuclear Information System (INIS)

    Natural radiation survey has been performed to characterize the gamma and cosmic ray dose rate distribution in living environment. Various places/environments which we encounter in our daily life were measured with high precision dose rate meter equipped with a pulse height spectrum-to-dose rate converter and a 7.6 cm diameter spherical NaI (Tl) scintillation detector. Several aspects of dose rate distribution have been found through these data; typical and interesting examples are as follows. (1) Gamma ray dose rates were measured inside and outside wooden houses in snowy season and in snowless season to see the effect of snow cover to the diminution of terrestrial gamma ray dose rate. The snow cover turned to be less effective inside a house than outside for the diminution of gamma ray dose rate. (2) Gamma ray dose rates were measured in a 2-storied concrete residence during its construction. The dose rate increased with progressing the construction, which implies that the indoor gamma ray dose rate depends not only on the building material but also on the building structure, that is the solid angle to the natural gamma ray sources such as the floor, ceiling and walls. (3) Continuous measurement was performed while a person made a business trip to Tokyo. Both gamma and cosmic ray dose rate showed a marked variation from place to place, which was found to be caused by the change of environmental conditions such as the nature and geometrical arrangement of the surrounding materials. Based on these data it was known that the gamma ray dose rate generally shows upward tendency and the cosmic ray dose rate downward in artificial environment compared with natural environment. (author)

  9. High Precision Cosmology with the Cosmic Background Radiation

    Science.gov (United States)

    Farhang, Marzieh

    In this thesis we investigate the two cosmic epochs of inflation and recombination, through their imprints on the temperature and polarization anisotropies of the cosmic microwave background radiation. To probe the early universe we develop a map-based maximum-likelihood estimator to measure the amplitude of inflation-induced gravity waves, parametrized by r, from the cosmic microwave background (CMB) polarization maps. Being optimal by construction, the estimator avoids E-B mixing, a possible source of contamination in the tiny B-mode detection, the target of many current and near future CMB experiments. We explore the leakage from the E- to the B-mode of polarization by using this estimator to study the linear response of the B-mode signal at different scales to variations in the E- mode power. Similarly, for various observational cases, we probe the dependence of r measurement on the signal from different scales of E and B polarization. The estimator is used to make forecasts for Spider-like and Planck-like experimental specifications and to investigate the sky-coverage optimization of the Spider-like case. We compare the forecast errors on r to the results from a similar multipole-based estimator which, by ignoring the mode-mixing, sets a lower limit on the achievable error on r. We find that an experiment with Spider-like specifications with fsky ˜ 0:02--0:2 could place a 2sigma r ≈ 0:014 bound (˜ 95% CL), which rises to 0:02 with an ℓ-dependent foreground residual left over from an assumed efficient component separation. For the Planck-like survey, a Galaxy-masked ( fsky = 0:75) sky would give 2sigmar ≈ 0:015, rising to ≈ 0:05 with the foreground residuals. We also use a novel information-based framework to compare how different generations of CMB experiments reveal information about the early universe, through their measurements of r. We also probe the epoch of recombination by investigating possible fluctuations in the free electron fraction Xe

  10. Effect of low dose ionizing radiation upon concentration of

    Energy Technology Data Exchange (ETDEWEB)

    Viliae, M.; Kraljeviae, P.; Simpraga, M.; Miljaniae, S.

    2004-07-01

    It is known that low dose ionizing radiation might have stimulating effects (Luckey, 1982, Kraljeviae, 1988). This fact has also been confirmed in the previous papers of Kraljeviae et al. (2000-2000a; 2001). Namely, those authors showed that irradiation of chicken eggs before incubation by a low dose of 0.15 Gy gamma radiation increases the activity aspartateaminotrasferases (AST) and alanine-aminotransferases (ALT) in blood plasma of chickens hatched from irradiated eggs, as well as growth of chickens during the fattening period. Low doses might also cause changes in the concentration of some biochemical parameters in blood plasma of the same chickens such as changes in the concentration of total proteins, glucose and cholesterol. In this paper, an attempt was made to investigate the effects of low dose gamma radiation upon the concentration of sodium and potassium in the blood plasma of chickens which were hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy. Obtained results were compared with the results from the control group (chickens hatched from nonirradiated eggs). After hatching, all other conditions were the same for both groups. Blood samples were drawn from heart, and later from the wing vein on days 1, 3, 5, 7, 10, 20, 30 and 42. The concentration of sodium and potassium was determined spectrophotometrically by atomic absorbing spectrophotometer Perkin-Elmer 1100B. The concentration of sodium and potassium in blood plasma of chickens hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy indicated a statistically significant increase (P>0.01) only on the first day of the experiment. Obtained results showed that irradiation of eggs on the 19th day of incubation by dose of 0.15 Gy gamma radiation could have effects upon the metabolism of electrolytes in chickens. (Author)

  11. Problems in radiation absorbed dose estimation from positron emitters

    International Nuclear Information System (INIS)

    The positron emitters commonly used in clinical imaging studies for the most part are short-lived, so that when they are distributed in the body the radiation absorbed dose is low even though most of the energy absorbed is from the positrons themselves rather than the annihilation radiation. These considerations do not apply to the administration pathway for a radiopharmaceutical where the activity may be highly concentrated for a brief period rather than distributed in the body. Thus, high local radiation absorbed doses to the vein for an intravenous administration and to the upper airways during administration by inhalation can be expected. For these geometries, beta point source functions (FPS's) have been employed to estimate the radiation absorbed dose in the present study. Physiologic measurements were done to determine other exposure parameters for intravenous administration of O-15 and Rb-82 and for administration of O-15-CO2 by continuous breathing. Using FPS's to calculate dose rates to the vein wall from O-15 and Rb-82 injected into a vein having an internal radius of 1.5 mm yielded dose rates of 0.51 and 0.46 (rad x g/μCi x h), respectively. The dose gradient in the vein wall and surrounding tissues was also determined using FPS's. Administration of O-15-CO2 by continuous breathing was also investigated. Using ultra-thin thermoluninescent dosimeters (TLD's) having the effective thickness of normal tracheal mucosa, experiments were performed in which 6 dosimeters were exposed to known concentrations of O-15 positrons in a hemicylindrical tracheal phantom having an internal radius of 0.96 cm and an effective length of 14 cm. The dose rate for these conditions was 3.4 (rads/h)/(μCi/cm3). 15 references, 7 figures, 6 tables

  12. Application of maximum values for radiation exposure and principles for the calculation of radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The guide sets out the mathematical definitions and principles involved in the calculation of the equivalent dose and the effective dose, and the instructions concerning the application of the maximum values of these quantities. further, for monitoring the dose caused by internal radiation, the guide defines the limits derived from annual dose limits (the Annual Limit on Intake and the Derived Air Concentration). Finally, the guide defines the operational quantities to be used in estimating the equivalent dose and the effective dose, and also sets out the definitions of some other quantities and concepts to be used in monitoring radiation exposure. The guide does not include the calculation of patient doses carried out for the purposes of quality assurance.

  13. Low doses effects of ionizing radiation on Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The exposure of living cells to low doses of ionizing radiation induce in response the activation of cellular protection mechanisms against subsequent larger doses of radiation. This cellular adaptive response may vary depending on radiation intensity and time of exposure, and also on the testing probes used whether they were mammalian cells, yeast, bacteria and other organisms or cell types. The mechanisms involved are the genome activation, followed by DNA repair enzymes synthesis. Due to the prompt cell response, the cell cycle can be delayed, and the secondary detoxification of free radicals and/or activation of membrane bound receptors may proceed. All these phenomena are submitted to intense scientific research nowadays, and their elucidation will depend on the complexity of the organism under study. In the present work, the effects of low doses of ionizing radiation (gamma rays) over a suspension of the yeast Saccharomyces cerevisiae (Baker's yeast) was studied, mainly in respect to survival rate and radio-adaptive response. At first, the yeast surviving curve was assessed towards increasing doses, and an estimation of Lethal Dose 50 (LD50) was made. The irradiation tests were performed at LINAC (electrons Linear Accelerator) where electron energy reached approximately 2.65 MeV, and gamma-radiation was produced for bremsstrahlung process over an aluminium screen target. A series of experiments of conditioning doses was performed and an increment surviving fraction was observed when the dose was 2.3 Gy and a interval time between this and a higher dose (challenging dose) of 27 Gy was 90 minutes. A value of 58 ± 4 Gy was estimated for LD50, at a dose rate of 0.44 ± 0.03 Gy/min These quantities must be optimized. Besides data obtained over yeast survival, an unusual increasing amount of tiny yeast colonies appeared on the agar plates after incubation, and this number increased as increasing the time exposure. Preliminary results indicate these colonies as

  14. Low radiation dose imaging of myocardial perfusion and coronary angiography with a hybrid PET/CT scanner

    OpenAIRE

    Kajander, S; Ukkonen, H; Sipilä, H.; Teräs, M.; Knuuti, J

    2009-01-01

    Objectives: To test the image quality and feasibility of a sequential low radiation dose protocol for hybrid cardiac PET/CT angiography (CTA). Background: Multidetector computed tomography (MDCT) is a non-invasive method for coronary angiography. The negative predictive value of MDCT is high but perfusion imaging has a role in detecting functional significance of coronary lesions. This has encouraged combining these techniques. However, radiation dose is of concern. We report our first experi...

  15. Cancer risk from low doses of ionizing radiation

    International Nuclear Information System (INIS)

    The aim of the study was to estimate cancer risk from small doses of ionizing radiation from various sources, including both external and internal exposure. The types of radiation included alpha, gamma, and neutron radiation. A nationwide follow-up study covering the years up to 1992 revealed no significant association between fallout from the Chernobyl accident and incidence of childhood leukemia. An excess of eight cases or more per year could be excluded. However, some indication of an increase was evident in the most heavily affected areas. Furthermore, the risk estimates were in accordance with those reported from Hiroshima and Nagasaki, although the confidence intervals were wide. (282 refs.)

  16. A consideration of low dose radiation effects on human health

    International Nuclear Information System (INIS)

    On March 11, 2011, an earthquake categorized as 9 Mw occurred off the northeast coast of Japan. The subsequent destructive tsunami disabled emergency units of Fukushima Dai'ichi Nuclear Power Plant and caused partial meltdown of reactors and explosions. Resulting radiation releases forced large evacuations, bore concerns about food and water and fears against human health. In this manuscript, we described the effect of radiation, especially low dose radiation below 100 mSv, on cancer risk, focusing on fetuses and children. (author)

  17. Cancer risk from low doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Auvinen, A.

    1997-06-01

    The aim of the study was to estimate cancer risk from small doses of ionizing radiation from various sources, including both external and internal exposure. The types of radiation included alpha, gamma, and neutron radiation. A nationwide follow-up study covering the years up to 1992 revealed no significant association between fallout from the Chernobyl accident and incidence of childhood leukemia. An excess of eight cases or more per year could be excluded. However, some indication of an increase was evident in the most heavily affected areas. Furthermore, the risk estimates were in accordance with those reported from Hiroshima and Nagasaki, although the confidence intervals were wide. (282 refs.).

  18. Prenatal radiation exposure. Dose calculation; Praenatale Strahlenexposition. Dosisermittlung

    Energy Technology Data Exchange (ETDEWEB)

    Scharwaechter, C.; Schwartz, C.A.; Haage, P. [University Hospital Witten/Herdecke, Wuppertal (Germany). Dept. of Diagnostic and Interventional Radiology; Roeser, A. [University Hospital Witten/Herdecke, Wuppertal (Germany). Dept. of Radiotherapy and Radio-Oncology

    2015-05-15

    The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero X-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties.

  19. Evaluation of radiation doses and dose conversion coefficients for pediatric cardiac catheterization procedures

    International Nuclear Information System (INIS)

    Pediatric cardiac catheterization covers both diagnostic and therapeutic procedures that range from simple to complex and can subject pediatric patients to varying radiation doses. There is limited information on radiation doses delivered by pediatric cardiac catheterization procedures and there is no recommended reference dose levels established yet. The study aims to determine the variation in patient radiation doses in terms of dose area product values and effective doses; determine factors that contribute to high doses to optimize protection; and determine the effective dose conversion coefficient. It is also aimed to provide data to help in the establishment of reference dose levels. A total of 761 pediatric patients belonging to age groups 0, 1, 5 and 10 years who undergo diagnostic and three selected therapeutic procedures at King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia are included in the study. Therapeutic procedures include COA, PDA and pulmonary procedures. Fluoroscopy and cine radiography are used in all procedures. Patient demography (weight, age, gender and height), radiographic technique factors, fluoroscopy and cine time, frame rate, and dose area product values are taken from patients records. Results show that the kVp varies by ± 1 kVp between procedures and by ± 6 kVp between AP and oblique + lateral projection for all procedures. The mA for lateral and oblique is about 40-70% higher than for AP. Effective doses for each procedure are estimated from the DAP values. The mean DAP and effective dose per procedure are analyzed for correlation with patient equivalent cylindrical diameter, weight, fluoroscopy time and number of frames. Initial results show that age group 0 and 1 year old have the highest mean value for effective dose (11.3 and 13.8 mSv respectively) for pulmonary procedure. Pooling all ages for each procedure, the pulmonary and PDA procedures gave the highest mean values for effective dose (10 and 8.2 m

  20. Background study of absorbed dose in biological experiments at the Modane Underground Laboratory

    Science.gov (United States)

    Lampe, Nathanael; Marin, Pierre; Castor, Jean; Warot, Guillaume; Incerti, S.; Maigne, Lydia; Sarramia, David; Breton, Vincent

    2016-09-01

    Aiming to explore how biological systems respond to ultra-low background environ-ments, we report here our background studies for biological experiments in the Modane Under-ground Laboratory. We find that the minimum radioactive background for biology experiments is limited by the potassium content of the biological sample itself, coming from its nutritive me-dium, which we find in our experimental set-up to be 26 nGy hr-1. Compared to our reference radiation environment in Clermont-Ferrand, biological experiments can be conducted in the Modane laboratory with a radiation background 8.2 times lower than the reference above-ground level. As the radiation background may be further reduced by using different nutritive media, we also provide measurements of the potassium concentration by gamma spectroscopy of yeast extract (63.3±1.2 mg g-1) and tryptone (2.5±0.2 mg g-1) in order to guide media selection in future experiments.

  1. Radiation Dose from Medical Imaging: A Primer for Emergency Physicians

    Directory of Open Access Journals (Sweden)

    Jesse G.A. Jones, MD

    2012-05-01

    Full Text Available Introduction: Medical imaging now accounts for most of the US population’s exposure to ionizingradiation. A substantial proportion of this medical imaging is ordered in the emergency setting. We aimto provide a general overview of radiation dose from medical imaging with a focus on computedtomography, as well as a literature review of recent efforts to decrease unnecessary radiation exposureto patients in the emergency department setting.Methods: We conducted a literature review through calendar year 2010 for all published articlespertaining to the emergency department and radiation exposure.Results: The benefits of imaging usually outweigh the risks of eventual radiation-induced cancer inmost clinical scenarios encountered by emergency physicians. However, our literature review identified3 specific clinical situations in the general adult population in which the lifetime risks of cancer mayoutweigh the benefits to the patient: rule out pulmonary embolism, flank pain, and recurrent abdominalpain in inflammatory bowel disease. For these specific clinical scenarios, a physician-patientdiscussion about such risks and benefits may be warranted.Conclusion: Emergency physicians, now at the front line of patients’ exposure to ionizing radiation,should have a general understanding of the magnitude of radiation dose from advanced medicalimaging procedures and their associated risks. Future areas of research should include thedevelopment of protocols and guidelines that limit unnecessary patient radiation exposure.

  2. Comparison of measured and calculated peripheral doses in patients undergoing radiation therapy

    International Nuclear Information System (INIS)

    Background and purpose: Many papers have been published on the measurement for specific treatment machines and/or techniques of the dose to points outside the primary beam, often called the peripheral dose (PD). Most papers concern measurements in phantoms. We report on the results of a comparison of estimates of the PD, based on these phantom measurements, with PDs measured on patients. Material and methods: A special holder with thermoluminescent dosimeters was placed against the perineum of patients referred to our institute for radiation therapy. The measured dose was then compared with the dose calculated on the basis of published PD data. Results: For all measurements together, the calculated values exceeded the measured PDs by about 9%, with a standard deviation of 35%. The correlation varied between specific subgroups but the difference between measurement and calculation did not exceed 50%. Conclusions: We conclude that published PD data can be used to accurately predict the peripheral dose in the clinical situation

  3. Use of glasses as radiation detectors for high doses

    International Nuclear Information System (INIS)

    Glass samples were tested in relation to the possibility of use in high dose dosimetry in medical and industrial areas. The main characteristics were determined: detection threshold, reproducibility, response to gamma radiation of 137Cs and 6 Co and thermal decay at ambient temperature, with the use of optical absorption and thermoluminesce techniques. (author)

  4. Population doses from naturally occurring radiation in Norway

    International Nuclear Information System (INIS)

    The main purpose of this work was to study the radiological consequences of the introduction of building materials with high concentrations of radioactivity and to analyse the impact of a reduction of the ventilation rates in houses on the population dose from inhalation of natural airborne radioactivity. The general problems of radioactivity in building materials are discussed. Measurements of radioactivity in building materials from different parts of the country are reported, together with theoretical calculations of the gamma doses in houses. These calculations are compared with experimental results and earlier measurements of the indoor gamma radiation in Norway. Measurements of the outdoor gamma radiation in different parts of Norway are presented. These results are used together with earlier measurements of the gamma radiation inside houses to calculate the average, and variations of population dose from this radiation. An experimental study on the radon concentrations inside different types of dwellings, and a discussion of the respiratory dose received by the inhalation of radon daughters is presented. Some factors that may have influence upon the radon concentrations are also discussed. A method for measurement of radon and thoron daughters in air is discussed. The possible radiological effects of an increased radon concentration in houses are discussed. (Auth.)

  5. Dose loading mathematical modelling of moving through heterogeneous radiation fields

    International Nuclear Information System (INIS)

    Software component for management of data on gamma exposition dose spatial distribution was created in the frameworks of the Ukryttya information model creation. Availability of state-of-the-art programming technologies (NET., ObjectARX) for integration of different models of radiation-hazardous condition to digital engineer documentation system (AutoCAD) was shown on the basis of the component example

  6. On the radiation dose required to cure intracranial germinoma

    Energy Technology Data Exchange (ETDEWEB)

    Shibamoto, Yuta [Kyoto Univ. (Japan). Inst. for Frontier Medical Sciences

    1999-09-01

    Despite its high radiosensitivity, intracranial germinoma has most often been treated with a radiation dose of 50 Gy. Relatively old literature suggested that 50 Gy was appropriate, but several newer studies indicate that 40-45 Gy may be sufficient. Regarding this issue, we conducted a phase II study in which the total dose to the primary site was planned to be 40 Gy to tumors <2.5 cm in diameter, 45 Gy to 2.5-4 cm tumors, and 50 Gy to tumors >4 cm, using 1.6-1.8 Gy daily fractions. Thirty-eight patients were enrolled. Within a median follow-up period of 116 months, no patients developed local recurrence, and only two developed CSF dissemination. Intracranial germinoma <4 cm in diameter can be cured with radiation doses of 40-45 Gy. Radiotherapy alone with these reduced doses should be compared with the ongoing protocols of chemotherapy plus further reduced dose (24-30 Gy) radiation in future studies. (author)

  7. Individual radiation doses registration, management and information system

    International Nuclear Information System (INIS)

    Full text: One of the important parts of dose monitoring is proper recording of radiation doses and share of information with responsible personal and customers. International organizations stressing the necessity for harmonization of dose record keeping systems and specifying the data they may contain. Constant control on process of dosimeters issue, return, reading, data evaluation and personal dose calculation is essential part of quality system in dosimetry service. Keeping records of dosimeters wearing terms and conditions, damages, and other discharges can help dosimetry service to work with customers more efficiently. Analytical information, including time of analyses, the analyst names and analytical techniques used, analytical results, and quality assurance/quality control of such analyses could be used to improve quality of dosimetry service. The individual radiation doses registration, management and information system is developed and now is under implementation in Latvian Radiation Safety Centre. This system is more than just a computer based data storage system and displays results of all analyses, including laboratory reports and different summary tables or interpretive reports. Each step of dosimeters processing in the dosimetric laboratory is controlled and recorded. Contract and the other customer related information is stored in the system. Database uses standard MS Windows software, which makes it fully compatible with most computers. System is flexible, has friendly interface, possibility for modification of reports according to user requirements. Internet access option implemented in the system simplifies process information delivery to the customers. (author)

  8. Radiation-induced biomarkers for the detection and assessment of absorbed radiation doses

    Directory of Open Access Journals (Sweden)

    Sudha Rana

    2010-01-01

    Full Text Available Radiation incident involving living organisms is an uncommon but a very serious situation. The first step in medical management including triage is high-throughput assessment of the radiation dose received. Radiation exposure levels can be assessed from viability of cells, cellular organelles such as chromosome and different intermediate metabolites. Oxidative damages by ionizing radiation result in carcinogenesis, lowering of the immune response and, ultimately, damage to the hematopoietic system, gastrointestinal system and central nervous system. Biodosimetry is based on the measurement of the radiation-induced changes, which can correlate them with the absorbed dose. Radiation biomarkers such as chromosome aberration are most widely used. Serum enzymes such as serum amylase and diamine oxidase are the most promising biodosimeters. The level of gene expression and protein are also good biomarkers of radiation.

  9. Methionine Uptake and Required Radiation Dose to Control Glioblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Iuchi, Toshihiko, E-mail: tiuchi@chiba-cc.jp [Division of Neurological Surgery, Chiba Cancer Center, Chiba (Japan); Hatano, Kazuo [Division of Radiation Oncology, Tokyo Bay Advanced Imaging and Radiation Oncology Clinic, Makuhari, Chiba (Japan); Uchino, Yoshio [Division of Nuclear Medicine, Chiba Ryogo Center, Chiba (Japan); Itami, Makiko [Division of Surgical Pathology, Chiba Cancer Center, Chiba (Japan); Hasegawa, Yuzo; Kawasaki, Koichiro; Sakaida, Tsukasa [Division of Neurological Surgery, Chiba Cancer Center, Chiba (Japan); Hara, Ryusuke [Division of Radiation Oncology, Chiba Cancer Center, Chiba (Japan)

    2015-09-01

    Purpose: The purpose of this study was to retrospectively assess the feasibility of radiation therapy planning for glioblastoma multiforme (GBM) based on the use of methionine (MET) positron emission tomography (PET), and the correlation among MET uptake, radiation dose, and tumor control. Methods and Materials: Twenty-two patients with GBM who underwent MET-PET prior to radiation therapy were enrolled. MET uptake in 30 regions of interest (ROIs) from 22 GBMs, biologically effective doses (BEDs) for the ROIs and their ratios (MET uptake:BED) were compared in terms of whether the ROIs were controlled for >12 months. Results: MET uptake was significantly correlated with tumor control (odds ratio [OR], 10.0; P=.005); however, there was a higher level of correlation between MET uptake:BED ratio and tumor control (OR, 40.0; P<.0001). These data indicated that the required BEDs for controlling the ROIs could be predicted in terms of MET uptake; BED could be calculated as [34.0 × MET uptake] Gy from the optimal threshold of the MET uptake:BED ratio for tumor control. Conclusions: Target delineation based on MET-PET was demonstrated to be feasible for radiation therapy treatment planning. MET-PET could not only provide precise visualization of infiltrating tumor cells but also predict the required radiation doses to control target regions.

  10. Dose response curves for effects of low-level radiation

    International Nuclear Information System (INIS)

    The linear dose-response model used by international committees to assess the genetic and carcinogenic hazards of low-level radiation appears to be the most reasonable interpretation of the available scientific data that are relevant to this topic. There are, of course, reasons to believe that this model may overestimate radiation hazards in certain instances, a fact acknowledged in recent reports of these committees. The linear model is now also being utilized to estimate the potential carcinogenic hazards of other agents such as asbestos and polycyclic aromatic hydrocarbons. This model implies that there is no safe dose for any of these agents and that potential health hazards will increase in direct proportion to total accumulated dose. The practical implication is the recommendation that all exposures should be kept 'as low as reasonably achievable, economic and social factors being taken into account'. (auth)

  11. Impact of dose calculation algorithm on radiation therapy

    Institute of Scientific and Technical Information of China (English)

    Wen-Zhou; Chen; Ying; Xiao; Jun; Li

    2014-01-01

    The quality of radiation therapy depends on the ability to maximize the tumor control probability while minimizing the normal tissue complication probability.Both of these two quantities are directly related to the accuracy of dose distributions calculated by treatment planning systems.The commonly used dose calculation algorithms in the treatment planning systems are reviewed in this work.The accuracy comparisons among these algorithms are illustrated by summarizing the highly cited research papers on this topic.Further,the correlation between the algorithms and tumor control probability/normal tissue complication probability values are manifested by several recent studies from different groups.All the cases demonstrate that dose calculation algorithms play a vital role in radiation therapy.

  12. Attributability of Health Effects at Low Radiation Doses

    International Nuclear Information System (INIS)

    Full text: A controversy still persists on whether health effects can be alleged from radiation exposure situations involving low radiation doses (e.g. below the international dose limits for the public). Arguments have evolved around the validity of the dose response representation that is internationally used for radiation protection purposes, namely the so-called linear-non-threshold (LNT) model. The debate has been masked by the intrinsic randomness of radiation interaction at the cellular level and also by gaps in the relevant scientific knowledge on the development and expression of health effects. There has also been a vague use, abuse, and misuse of radiation-related risk concepts and quantities and their associated uncertainties. As a result, there is some ambiguity in the interpretation of the phenomena and a general lack of awareness of the implications for a number of risk-causation qualities, namely its attributes and characteristics. In particular, the LNT model has been used not only for protection purposes but also for blindly attributing actual effects to specific exposure situations. The latter has been discouraged as being a misuse of the model, but the supposed incorrectness has not been clearly proven. The paper will endeavour to demonstrate unambiguously the following thesis in relation to health effects due to low radiation doses: (i) Their existence is highly plausible. A number of epidemiological statistical assessments of sufficiently large exposed populations show that, under certain conditions, the prevalence of the effects increases with dose. From these assessments, it can be hypothesized that the occurrence of the effects at any dose, however small, appears decidedly worthy of belief. While strictly the evidence does not allow to conclude that a threshold dose level does not exist either In fact, a formal quantitative uncertainty analysis, combining the different uncertain components of estimated radiation-related risk, with and

  13. Attributability of health effects at low radiation doses

    International Nuclear Information System (INIS)

    Full text: A controversy still persists on whether health effects can be alleged from radiation exposure situations involving low radiation doses (e.g. below the international dose limits for the public). Arguments have evolved around the validity of the dose-response representation that is internationally used for radiation protection purposes, namely the so-called linear-non-threshold (LNT) model. The debate has been masked by the intrinsic randomness of radiation interaction at the cellular level and also by gaps in the relevant scientific knowledge on the development and expression of health effects. There has also been a vague use, abuse, and misuse of radiation-related risk concepts and quantities and their associated uncertainties. As a result, there is some ambiguity in the interpretation of the phenomena and a general lack of awareness of the implications for a number of risk-causation qualities, namely its attributes and characteristics. In particular, the LNT model has been used not only for protection purposes but also for blindly attributing actual effects to specific exposure situations. The latter has been discouraged as being a misuse of the model, but the supposed incorrectness has not been clearly proven. The paper will endeavour to demonstrate unambiguously the following thesis in relation to health effects due to low radiation doses: 1) Their existence is highly plausible. A number of epidemiological statistical assessments of sufficiently large exposed populations show that, under certain conditions, the prevalence of the effects increases with dose. From these assessments, it can be hypothesized that the occurrence of the effects at any dose, however small, appears decidedly worthy of belief. While strictly the evidence does not allow to conclude that a threshold dose level does not exist either. In fact, a formal quantitative uncertainty analysis, combining the different uncertain components of estimated radiation-related risk, with and

  14. In vitro cell culture lethal dose submitted to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Carolina S.; Rogero, Sizue O.; Rogero, Jose Roberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: carolina_sm@hotmail.com; Ikeda, Tamiko I.; Cruz, Aurea S. [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil)

    2009-07-01

    The present study was designed to evaluate the in vitro effect of gamma radiation in cell culture of mouse connective tissue exposed to different doses of gamma radiation and under several conditions. The cell viability was analyzed by neutral red uptake methodology. This assay was developed for establish a methodology to be used in the future in the study of resveratrol radioprotection. Resveratrol (3,4',5- trihydroxystilbene), a phenolic phytoalexin that occurs naturally in some spermatophytes, such as grapevines, in response to injury as fungal infections and exposure to ultraviolet light. In the wines this compound is found at high levels and is considered one of the highest antioxidant constituents. The intense antioxidant potential of resveratrol provides many pharmacological activities including cardioprotection, chemoprevention and anti-tumor effects. Our results demonstrated that {sup 60}Co gamma radiation lethal dose (LD50) on NCTC clone 929 cells was about 340Gy. (author)

  15. In vitro cell culture lethal dose submitted to gamma radiation

    International Nuclear Information System (INIS)

    The present study was designed to evaluate the in vitro effect of gamma radiation in cell culture of mouse connective tissue exposed to different doses of gamma radiation and under several conditions. The cell viability was analyzed by neutral red uptake methodology. This assay was developed for establish a methodology to be used in the future in the study of resveratrol radioprotection. Resveratrol (3,4',5- trihydroxystilbene), a phenolic phytoalexin that occurs naturally in some spermatophytes, such as grapevines, in response to injury as fungal infections and exposure to ultraviolet light. In the wines this compound is found at high levels and is considered one of the highest antioxidant constituents. The intense antioxidant potential of resveratrol provides many pharmacological activities including cardioprotection, chemoprevention and anti-tumor effects. Our results demonstrated that 60Co gamma radiation lethal dose (LD50) on NCTC clone 929 cells was about 340Gy. (author)

  16. PET/CT-guided Interventions: Personnel Radiation Dose

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, E. Ronan, E-mail: ronan@ronanryan.com; Thornton, Raymond; Sofocleous, Constantinos T.; Erinjeri, Joseph P. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Hsu, Meier [Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics (United States); Quinn, Brian; Dauer, Lawrence T. [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics (United States); Solomon, Stephen B. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States)

    2013-08-01

    PurposeTo quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.MethodsIn this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).ResultsThe median effective dose was 0.02 (range 0-0.13) mSv for the primary operator, 0.01 (range 0-0.05) mSv for the nurse anesthetist, and 0.02 (range 0-0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0-0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).ConclusionThe operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient.

  17. The effect of radiation dose on mouse skeletal muscle remodeling

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the effect of two clinically relevant radiation doses on the susceptibility of mouse skeletal muscle to remodeling. Alterations in muscle morphology and regulatory signaling were examined in tibialis anterior and gastrocnemius muscles after radiation doses that differed in total biological effective dose (BED). Female C57BL/6 (8-wk) mice were randomly assigned to non-irradiated control, four fractionated doses of 4 Gy (4x4 Gy; BED 37 Gy), or a single 16 Gy dose (16 Gy; BED 100 Gy). Mice were sacrificed 2 weeks after the initial radiation exposure. The 16 Gy, but not 4x4 Gy, decreased total muscle protein and RNA content. Related to muscle regeneration, both 16 Gy and 4x4 Gy increased the incidence of central nuclei containing myofibers, but only 16 Gy increased the extracellular matrix volume. However, only 4x4 Gy increased muscle 4-hydroxynonenal expression. While both 16 Gy and 4x4 Gy decreased IIB myofiber mean cross-sectional area (CSA), only 16 Gy decreased IIA myofiber CSA. 16 Gy increased the incidence of small diameter IIA and IIB myofibers, while 4x4 Gy only increased the incidence of small diameter IIB myofibers. Both treatments decreased the frequency and CSA of low succinate dehydrogenase activity (SDH) fibers. Only 16 Gy increased the incidence of small diameter myofibers having high SDH activity. Neither treatment altered muscle signaling related to protein turnover or oxidative metabolism. Collectively, these results demonstrate that radiation dose differentially affects muscle remodeling, and these effects appear to be related to fiber type and oxidative metabolism

  18. Radiation doses from computed tomography practice in Johor Bahru, Malaysia

    Science.gov (United States)

    Karim, M. K. A.; Hashim, S.; Bradley, D. A.; Bakar, K. A.; Haron, M. R.; Kayun, Z.

    2016-04-01

    Radiation doses for Computed Tomography (CT) procedures have been reported, encompassing a total of 376 CT examinations conducted in one oncology centre (Hospital Sultan Ismail) and three diagnostic imaging departments (Hospital Sultanah Aminah, Hospital Permai and Hospital Sultan Ismail) at Johor hospital's. In each case, dose evaluations were supported by data from patient questionnaires. Each CT examination and radiation doses were verified using the CT EXPO (Ver. 2.3.1, Germany) simulation software. Results are presented in terms of the weighted computed tomography dose index (CTDIw), dose length product (DLP) and effective dose (E). The mean values of CTDIw, DLP and E were ranged between 7.6±0.1 to 64.8±16.5 mGy, 170.2±79.2 to 943.3±202.3 mGy cm and 1.6±0.7 to 11.2±6.5 mSv, respectively. Optimization techniques in CT are suggested to remain necessary, with well-trained radiology personnel remaining at the forefront of such efforts.

  19. Background radiation and individual dosimetry in the costal area of Tamil Nadu, India.

    Science.gov (United States)

    Matsuda, Naoki; Brahmanandhan, G M; Yoshida, Masahiro; Takamura, Noboru; Suyama, Akihiko; Koguchi, Yasuhiro; Juto, Norimichi; Raj, Y Lenin; Winsley, Godwin; Selvasekarapandian, S

    2011-07-01

    South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2×7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1).

  20. Radiation doses to neonates and issues of radiation protection in a special care baby unit

    International Nuclear Information System (INIS)

    Radiographs are most commonly taken in the neonatal period to assist in the diagnosis and management of respiratory difficulties. Frequent accurate radiographic assessment is required and a knowledge of the radiation dose is necessary to make the justification of such exposures. A survey of radiation doses to neonates from diagnostic X-ray examinations (chest and abdomen) has been carried out in the special care baby unit (SCBU) of the Royal Free Hospital. Entrance surface dose (ESD) was calculated from Quality Control measurements on the X-ray set itself. Direct measurement of radiation doses was also performed using highly sensitive thermoluminescence dosimeters (LiF:Mg,Cu,P), calibrated and tested for consistency in sensitivity. The mean ESD per radiograph was calculated to be 36μGy (with a standard deviation of 6μGy), averaged over 95 X-ray examinations. The ESD's as derived from the TLD crystals, ranged from 18μGy to 60μGy. The mean energy imparted (EI) and the mean whole body dose per radiograph were estimated to be 14μJ and 10μGy respectively. Assuming that neonates and foetuses are equally susceptible to carcinogenic effects of radiation (it involves an overestimation of risk), the radiation risk of childhood cancer from a single radiograph was estimated to be of the order (0.3-1.3)x10-6. Radiation doses compared favourably with the reference value of 80μGy ESD published by CEC in 1996. (author)

  1. Contribution of maternal radionuclide burdens to prenatal radiation doses

    International Nuclear Information System (INIS)

    This report describes approaches to calculating and expressing radiation doses to the embryo/fetus from internal radionuclides. Information was obtained for selected, occupationally significant radioelements that provide a spectrum of metabolic and dosimetric characteristics. Evaluations are also presented for inhaled inert gases and for selected radiopharmaceuticals. Fractional placental transfer and/or ratios of concentration in the embryo/fetus to that in the woman were calculated for these materials. The ratios were integrated with data from biokinetic transfer models to estimate radioactivity levels in the embryo/fetus as a function of stage of pregnancy and time after entry into the transfer compartment or blood of the pregnant woman. These results are given as tables of deposition and retention in the embryo/fetus as a function of gestational age at exposure and elapsed time following exposure. Methodologies described by MIRD were extended to formalize and describe details for calculating radiation absorbed doses to the embryo/fetus. Calculations were performed using a model situation that assumed a single injection of 1 μCi into a woman's blood; independent calculations were performed for administration at successive months of pregnancy. Gestational -stage-dependent dosimetric tabulations are given together with tables of correlations and relationships. Generalized surrogate dose factors and categorizations are provided in the report to provide for use in operational radiological protection situations. These approaches to calculation yield radiation absorbed doses that can be converted to dose equivalent by multiplication by quality factor. Dose equivalent is the most common quantity for stating prenatal dose limits in the United States and is appropriate for the types of effect that are usually associated with prenatal exposure. If it is desired to obtain alternatives for other purposes, this value can be multiplied by appropriate weighting factors

  2. Contribution of maternal radionuclide burdens to prenatal radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Sikov, M.R.; Hui, T.E.

    1996-05-01

    This report describes approaches to calculating and expressing radiation doses to the embryo/fetus from internal radionuclides. Information was obtained for selected, occupationally significant radioelements that provide a spectrum of metabolic and dosimetric characteristics. Evaluations are also presented for inhaled inert gases and for selected radiopharmaceuticals. Fractional placental transfer and/or ratios of concentration in the embryo/fetus to that in the woman were calculated for these materials. The ratios were integrated with data from biokinetic transfer models to estimate radioactivity levels in the embryo/fetus as a function of stage of pregnancy and time after entry into the transfer compartment or blood of the pregnant woman. These results are given as tables of deposition and retention in the embryo/fetus as a function of gestational age at exposure and elapsed time following exposure. Methodologies described by MIRD were extended to formalize and describe details for calculating radiation absorbed doses to the embryo/fetus. Calculations were performed using a model situation that assumed a single injection of 1 {mu}Ci into a woman`s blood; independent calculations were performed for administration at successive months of pregnancy. Gestational -stage-dependent dosimetric tabulations are given together with tables of correlations and relationships. Generalized surrogate dose factors and categorizations are provided in the report to provide for use in operational radiological protection situations. These approaches to calculation yield radiation absorbed doses that can be converted to dose equivalent by multiplication by quality factor. Dose equivalent is the most common quantity for stating prenatal dose limits in the United States and is appropriate for the types of effect that are usually associated with prenatal exposure. If it is desired to obtain alternatives for other purposes, this value can be multiplied by appropriate weighting factors.

  3. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    Science.gov (United States)

    Wang, Chu

    Patients undergoing cardiac catheterization are potentially at risk of radiation-induced health effects from the interventional fluoroscopic X-ray imaging used throughout the clinical procedure. The amount of radiation exposure is highly dependent on the complexity of the procedure and the level of optimization in imaging parameters applied by the clinician. For cardiac catheterization, patient radiation dosimetry, for key organs as well as whole-body effective, is challenging due to the lack of fixed imaging protocols, unlike other common X-ray based imaging modalities. Pediatric patients are at a greater risk compared to adults due to their greater cellular radio-sensitivities as well as longer remaining life-expectancy following the radiation exposure. In terms of radiation dosimetry, they are often more challenging due to greater variation in body size, which often triggers a wider range of imaging parameters in modern imaging systems with automatic dose rate modulation. The overall objective of this dissertation was to develop a comprehensive method of radiation dose estimation for pediatric patients undergoing cardiac catheterization. In this dissertation, the research is divided into two main parts: the Physics Component and the Clinical Component. A proof-of-principle study focused on two patient age groups (Newborn and Five-year-old), one popular biplane imaging system, and the clinical practice of two pediatric cardiologists at one large academic medical center. The Physics Component includes experiments relevant to the physical measurement of patient organ dose using high-sensitivity MOSFET dosimeters placed in anthropomorphic pediatric phantoms. First, the three-dimensional angular dependence of MOSFET detectors in scatter medium under fluoroscopic irradiation was characterized. A custom-made spherical scatter phantom was used to measure response variations in three-dimensional angular orientations. The results were to be used as angular dependence

  4. Biological dose assessment of 15 victims in Haerbin radiation accident

    International Nuclear Information System (INIS)

    Full text: a) On July 5 and 8, 2005, Two patients with bone marrow suppression were successively hospitalized by the First Affiliated Hospital of Haerbin Medical University. Examination results showed that the patients seemed to get suspicious radiation disease. On July 13, 2005, a radioactive source was found in the patients' dwelling. The radiation source is Iridium-192 with 0.5 Ci(1.85 x 1010Bq) radioactivity. The radiation source is a metal bar which is a kind of radioactive industrial detection source for welding. The source is currently stored in the urban radioactive waste storehouse of Heilongjiang province. After finding the radioactive source on July 13, The Haerbin municipal government initiated an emergency response plan and developed medical rescue, radioactive source examination and case detection through organizing ministries involving health, environmental protection and public security. After receiving a report at 17:00 on July 14, 2005, Chinese Ministry of Health immediately sent experts to the spot for investigation, dose estimation and direction of patients' rescue. Health authority carried out physical examination twice on 113 residents within 30 meters to the source, among which 4 got radiation sickness, 5 showed abnormal hemotogram, and others showed no abnormal response. Of 4 patients with radiation sickness, one 81 year old patient has died of severe bone marrow form of sub acute radiation sickness coupled with lung infection and prostrate apparatus at 13:00 on Oct., 20. Two children have been treated in Beitaiping Road Hospital in Beijing, another patient has been treated in local hospital. b) Biological dosimetry using conventional chromosome aberration analysis in human peripheral blood lymphocytes has been shown as a reliable and useful tool in medical management of radiation accident victims. Peripheral blood lymphocytes of the victims were cultured using conventional culture medium with colchicine added at the beginning. Chromosome

  5. Effects of low dose gamma radiation on the early growth of red pepper and the resistance to subsquent high dose of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Baek, M. H.; Kim, D. H.; Lee, Y. K. [KAERI, Taejon (Korea, Republic of); Lee, Y. B. [Chungnam National Univ., Taejon (Korea, Republic of)

    2001-05-01

    Red pepper (capsicum annuum L. cv. Jokwang and cv. Johong) seeds were irradiated with the dose of 0{approx}50 Gy to investigated the effect of the low dose gamma radiation on the early growth and resistance to subsequent high dose of radiation. The effect of the low dose gamma radiation on the early growth and resistance to subsequenct high dose of radiation were enhanced in Johong cultivar but not in Jokwang cultivar. Germination rate and early growth of Johong cultivar were noticeably increased at 4 Gy-, 8 Gy- and 20 Gy irradiation group. Resistance to subsequent high dose of radiation of Johong cultivar were increased at almost all of the low dose irradiation group. Especially it was highest at 4 Gy irradiation group. The carotenoid contents and enzyme activity on the resistance to subsequent high dose of radiation of Johong cultivar were increased at the 4 Gy and 8 Gy irradiation group.

  6. Radiation doses to staff on a department of nuclear medicine

    International Nuclear Information System (INIS)

    A survey of data concerning radiation protection of staff working in the Nuclear Medicine Department and associated sections of the Physics Department at the Royal Marsden Hospital (Surrey Branch) is given for the period 1972 to 1975 inclusive. Results of routine film monitoring and whole-body counting are presented. Additional film monitors were used to check working areas, finger doses and any discrepancies between doses to the upper and lower trunk of personnel. In general, exposure to staff in the Nuclear Medicine Department is below 220 mrad per person per year, and below 1,000 mrad per person per year in the Radioisotope Dispensary. The dose received by radiographers is primarily due to spending time close to patients. Since about 5,000 intravenous injections of radionuclides are given each year in this department, the resulting finger doses to the staff involved may give rise to concern unless the task is shared. (author)

  7. Radiation Background and Attenuation Model Validation and Development

    Energy Technology Data Exchange (ETDEWEB)

    Peplow, Douglas E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Santiago, Claudio P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-08-05

    This report describes the initial results of a study being conducted as part of the Urban Search Planning Tool project. The study is comparing the Urban Scene Simulator (USS), a one-dimensional (1D) radiation transport model developed at LLNL, with the three-dimensional (3D) radiation transport model from ORNL using the MCNP, SCALE/ORIGEN and SCALE/MAVRIC simulation codes. In this study, we have analyzed the differences between the two approaches at every step, from source term representation, to estimating flux and detector count rates at a fixed distance from a simple surface (slab), and at points throughout more complex 3D scenes.

  8. Low doses effects and gamma radiations low dose rates; Les effets des faibles doses et des faibles debits de doses de rayons gamma

    Energy Technology Data Exchange (ETDEWEB)

    Averbeck, D. [Institut Curie, CNRS UMR 2027, 75 - Paris (France)

    1999-07-01

    This expose wishes for bringing some definitions and base facts relative to the problematics of low doses effects and low dose rates effects. It shows some already used methods and some actual experimental approaches by focusing on the effects of ionizing radiations with a low linear energy transfer. (N.C.)

  9. Radiation doses to children during modified barium swallow studies

    International Nuclear Information System (INIS)

    There are minimal data on radiation doses to infants and children undergoing a modified barium swallow (MBS) study. To document screening times, dose area product (DAP) and effective doses to children undergoing MBS and to determine factors associated with increased screening times and effective dose. Fluoroscopic data (screening time, DAP, kVp) for 90 consecutive MBS studies using pulse fluoroscopy were prospectively recorded; effective dose was calculated and data were analyzed for effects of behavior, number of swallow presentations, swallowing dysfunction and medical problems. Mean effective dose for the entire group was 0.0826 ± 0.0544 mSv, screening time 2.48 ± 0.81 min, and DAP 28.79 ± 41.72 cGy cm2. Significant differences were found across three age groups (≤1.0, >1.0-3.0 and >3.0 years) for effective dose (mean 0.1188, 0.0651 and 0.0529 mSv, respectively; P < 0.001), but not for screening time or DAP. Effective dose was correlated with screening time (P 0.007), DAP (P < 0.001), number of swallow presentations (P = 0.007), lower age (P = 0.017), female gender (P = 0.004), and height (P < 0.001). Screening time was correlated with total number of swallow presentations (P < 0.001) and DAP (P < 0.001). Screening times, DAP, effective dose, and child and procedural factors associated with higher effective doses are presented for children undergoing MBS studies. (orig.)

  10. Radiation doses to children during modified barium swallow studies

    Energy Technology Data Exchange (ETDEWEB)

    Weir, Kelly A. [University of Queensland, Discipline of Paediatrics and Child Health, School of Medicine, Herston, Queensland (Australia); McMahon, Sandra M. [SpeechNet Speech Pathology Services, Brisbane (Australia); Long, Gillian; Bunch, Judith A. [Royal Children' s Hospital, Department of Medical Imaging, Herston (Australia); Pandeya, Nirmala [Queensland Institute of Medical Research, Herston (Australia); Coakley, Kerry S. [Biomedical Technology Services, Royal Brisbane and Women' s Hospital, Herston (Australia); Chang, Anne B. [Royal Children' s Hospital, Department of Respiratory Medicine, Herston (Australia)

    2007-03-15

    There are minimal data on radiation doses to infants and children undergoing a modified barium swallow (MBS) study. To document screening times, dose area product (DAP) and effective doses to children undergoing MBS and to determine factors associated with increased screening times and effective dose. Fluoroscopic data (screening time, DAP, kVp) for 90 consecutive MBS studies using pulse fluoroscopy were prospectively recorded; effective dose was calculated and data were analyzed for effects of behavior, number of swallow presentations, swallowing dysfunction and medical problems. Mean effective dose for the entire group was 0.0826 {+-} 0.0544 mSv, screening time 2.48 {+-} 0.81 min, and DAP 28.79 {+-} 41.72 cGy cm{sup 2}. Significant differences were found across three age groups ({<=}1.0, >1.0-3.0 and >3.0 years) for effective dose (mean 0.1188, 0.0651 and 0.0529 mSv, respectively; P < 0.001), but not for screening time or DAP. Effective dose was correlated with screening time (P = 0.007), DAP (P < 0.001), number of swallow presentations (P = 0.007), lower age (P = 0.017), female gender (P = 0.004), and height (P < 0.001). Screening time was correlated with total number of swallow presentations (P < 0.001) and DAP (P < 0.001). Screening times, DAP, effective dose, and child and procedural factors associated with higher effective doses are presented for children undergoing MBS studies. (orig.)

  11. Radiation doses from Hanford site releases to the atmosphere

    International Nuclear Information System (INIS)

    Radiation doses to individuals were estimated for the years 1944-1992. The dose estimates were based on the radioactive-releases from the Hanford Site in south central Washington. Conceptual models and computer codes were used to reconstruct doses through the early 1970s. The published Hanford Site annual environmental data were used to complete the does history through 1992. The most significant exposure pathway was found to be the consumption of cow's milk containing iodine-131. For the atmospheric pathway, median cumulative dose estimates to the thyroid of children ranged from < 0.1 to 235 rad throughout the area studied. The geographic distribution of the dose levels was directly related to the pattern of iodine-131 deposition and was affected by the distribution of commercial milk and leafy vegetables. For the atmospheric pathway, the-highest estimated cumulative-effective-dose-equivalent (EDE) to an adult was estimated to be 1 rem at Ringold, Washington for the period 1944-1992. For the Columbia River pathway, cumulative EDE estimates ranged from <0.5 to l.5 rem cumulative dose to maximally exposed adults downriver from the Hanford Site for the years 1944-1992. The most significant river exposure pathway was consumption of resident fish containing phosphorus-32 and zinc-65

  12. Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff

    International Nuclear Information System (INIS)

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R50%); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D2cm) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ2 test was used to examine the difference in parameters between groups. The PTV V100% PD ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V90% PD ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D2cm, 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives

  13. Strategies to reduce radiation dose in cardiac PET/CT

    Science.gov (United States)

    Wu, Tung Hsin; Wu, Nien-Yun; Wang, Shyh-Jen; Wu, Jay; S. P. Mok, Greta; Yang, Ching-Ching; Huang, Tzung-Chi

    2011-08-01

    Our aim was to investigate CT dose reduction strategies on a hybrid PET/CT scanner for cardiac applications.MaterialsImage quality and dose estimation of different CT scanning protocols for CT coronary angiography (CTCA), and CT-based attenuation correction for PET imaging were investigated. Fifteen patients underwent CTCA, perfusion PET imaging at rest and under stress, and FDG PET for myocardial viability. These patients were divided into three groups based on the CTCA technique performed: retrospectively gated helical (RGH), ECG tube current modulation (ETCM), and prospective gated axial (PGA) acquisitions. All emission images were corrected for photon attenuation using CT images obtained by default setting and an ultra-low dose CT (ULDCT) scan.ResultsRadiation dose in RGH technique was 22.2±4.0 mSv. It was reduced to 10.95±0.82 and 4.13±0.31 mSv using ETCM and PGA techniques, respectively. Radiation dose in CT transmission scan was reduced by 96.5% (from 4.53±0.5 to 0.16±0.01 mSv) when applying ULDCT as compared to the default CT. No significant difference in terms of image quality was found among various protocols.ConclusionThe proposed CT scanning strategies, i.e. ETCM or PGA for CTCA and ULDCT for PET attenuation correction, could reduce radiation dose up to 47% without degrading imaging quality in an integrated cardiac PET/CT coronary artery examination.

  14. Optimization of radiation protection exemplified by job-related doses

    International Nuclear Information System (INIS)

    For recurrent work on nuclear steam generators it is demonstrated, what factors have dominated the radiation exposures in nuclear power plants and how dose increasing effects were counteracted. As primary influencing factors, besides the dose rate in the working place, the extent of inspections and the occurrence of defects at steam generator tubes can be shown. The evaluated radiation level is characteristic for all work at the primary circuit. Possibilities for reducing the dose rate have been recognized and realized rather early (coolant chemistry). An increasing extent of inspection as dose influencing parameter can be noticed especially for the ultrasonic/surface inspection of the steam generators. A solution was sought and found in the reduction of preparation work and in automatisation. Defects by corrosion at the steam generator tubes are presumably the strongest influencing factor. Counter-measures were here especially the change of the tube material, improvement of methods for repairs and inspections as well as constructive changes at new steam generators. All works have in common a dose reduction by increasing experience and training, what can be clearly shown especially for the eddy current test of tubes. (orig./HP)

  15. The relationship between compression force, image quality and radiation dose in mammography

    Directory of Open Access Journals (Sweden)

    A Korf

    2009-11-01

    Full Text Available Background. Mammography aims to obtain mammograms of best possible image quality with least possible radiation dose.1 Theoretically, an increase in breast compression gives a reduction in thickness, without changing the density, resulting in improved image quality and reduced radiation dose. Aim.\tThis study aims to investigate the relationship between compression force, phantom thickness, image quality and radiation dose. The existence of a compression point beyond which increased compression gives a change in density rather than thickness is also considered. Method. Image quality is assessed with a contrast-detail phantom within Superflab phantom on a computed radiography (CR mammography unit using automatic exposure control (AEC. Image quality is determined by visual inspection and image quality figure (IQF scoring. The effect of compression and lesion depth on image quality is determined. Entrance and exit doses are calculated. The relationship between entrance dose, compression and thickness is investigated, as is the existence of a compression point beyond which a change in phantom density occurs. The average glandular dose (AGD is calculated from the scanning average level (SAL and logarithmic mean (LgM according to Koen et al,2 and compared to the allowable limit. Results.\tThe geometry effect was not observed. An improvement in image quality with increased compression was found. Entrance dose did decrease with increased compression. This trend was not observed with exit dose as AEC was used and exit dose was calculated from SAL values. The “change-in-density” point of compression was determined. Both LgM and SAL could be used successfully for AGD calculation.

  16. Radioactivity in Soil and Building Materials and Gamma Radiation Doses Committed to Alexandria Population

    International Nuclear Information System (INIS)

    The natural radionuclides (238 U, 232Th, and40 K) contents of soil samples at various locations in Alexandria, building materials, commonly used in Alexandria and road construction materials have been determined by low background spectroscopy using HPGeD of coaxial type. From the measured radionuclide contents, estimation have been made of the absorbed dose rate of gamma radiation in indoor and outdoor air. Finally, calculations have been carried out of the annual effective dose equivalent for the Alexandria population. The estimated value is 0.56 m Sv from indoor and 0.06 m Sv from outdoor

  17. Low dose radiation enhances the Locomotor activity of D. melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Ki Moon; Lee, Buyng Sub; Nam Seon Young; Kim, Ji Young; Yang, Kwang Hee; Choi, Tae In; Kim, Cha Soon [Radiation Effect Research Team, Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., Gyeongju (Korea, Republic of)

    2013-04-15

    Mild stresses at low level including radiation can induce the beneficial effects in many vertebrate and invertebrate species. However, a large amount of studies in radiation biology have focused on the detrimental effects of high dose radiation (HDR) such as the increased incidence of cancers and developmental diseases. Low dose radiation (LDR) induces biologically favorable effects in diverse fields, for example, cancer development, genomic instability, immune response, and longevity. Our previous data indicated that LDR promotes cells proliferation of which degree is not much but significant, and microarray data explained that LDR irradiated fruit flies showing the augmented immunity significantly changed the program for gene expression of many genes in Gene Ontology (GO) categories related to metabolic process. Metabolic process in development one of major contributors in organism growth, interbreeding, motility, and aging. Therefore, it is valuable to examine whether LDR change the physiological parameters related to metabolism, and how LDR regulates the metabolism in D. melanogaster. In this study, to investigate that LDR influences change of the metabolism, a representative parameter, locomotor activity. In addition, the activation of several cellular signal molecules was determined to investigate the specific molecular mechanism of LDR effects on the metabolism. We explored whether ionizing radiation affects the motility activity. We performed the RING assays to evaluate the locomotor activity, a representative parameter presenting motility of fruit flies. HDR dramatically decreased the motor activity of irradiated flies. Surprisingly, the irradiated flies at low dose radiation in both acute and chronic showed the significantly increased locomotor activity, compared to non-irradiated flies. Irradiation would induce change of the several signal pathways for flies to respond to it. The activation of some proteins involved in the cells proliferation and stress

  18. Radiation leakage dose from Elekta electron collimation system.

    Science.gov (United States)

    Pitcher, Garrett M; Hogstrom, Kenneth R; Carver, Robert L

    2016-01-01

    This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-field dose profiles. Off-axis dose profiles were measured in a water phantom at 100 cm SSD for 1 and 2 cm depths along the in-plane, cross-plane, and both diagonal axes using a cylindrical ionization chamber with the 10 × 10 and 20 × 20 cm2 applicators and 7, 13, and 20 MeV beams. Dose distributions were calculated using a previously developed BEAMnrc MC model of the Elekta Infinity accelerator for the same beam energies and applicator sizes and compared with measurements. Measured results showed that the in-field beam flatness met our acceptance criteria (± 3% on major and ±4% on diagonal axes) and that out-of-field mean and maximum percent leakage doses in the patient plane met acceptance criteria as specified by the International Electrotechnical Commission (IEC). Cross-plane out-of-field dose profiles showed greater leakage dose than in-plane profiles, attributed to the curved edges of the upper X-ray jaws and multileaf collimator. Mean leakage doses increased with beam energy, being 0.93% and 0.85% of maximum central axis dose for the 10 × 10 and 20 × 20 cm2 applicators, respectively, at 20 MeV. MC calculations predicted the measured dose to within 0.1% in most profiles outside the radiation field; however, excluding model-ing of nontrimmer applicator components led to calculations exceeding measured data by as much as 0.2% for some regions

  19. Response of radiation monitors for ambient dose equivalent, H*(10)

    International Nuclear Information System (INIS)

    Radiation monitors are used all over the world to evaluate if places with presence of ionising radiation present safe conditions for people. Radiation monitors should be tested according to international or national standards in order to be qualified for use. This work describes a methodology and procedures to evaluate the energy and angular responses of any radiation monitor for ambient dose equivalent, H*(10), according to the recommendations of ISO and IEC standards. The methodology and the procedures were applied to the Monitor Inteligente de Radiacao MIR 7026, developed by the Instituto em Engenharia Nuclear (IEN), to evaluate and to adjust its response for H*(10), characterizing it as an ambient dose equivalent meter. The tests were performed at the Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI), at Instituto de Radioprotecao e Dosimetria (IRD), and results showed that the Monitor Inteligente de Radiacao MIR 7026 can be used as an EI*(10) meter, in accordance to the IEC 60846 standard requirements. The overall estimated uncertainty for the determination of the MIR 7026 response, in all radiation qualities used in this work, was 4,5 % to a 95 % confidence limit. (author)

  20. Non-uniform dose distributions in cranial radiation therapy

    Science.gov (United States)

    Bender, Edward T.

    Radiation treatments are often delivered to patients with brain metastases. For those patients who receive radiation to the entire brain, there is a risk of long-term neuro-cognitive side effects, which may be due to damage to the hippocampus. In clinical MRI and CT scans it can be difficult to identify the hippocampus, but once identified it can be partially spared from radiation dose. Using deformable image registration we demonstrate a semi-automatic technique for obtaining an estimated location of this structure in a clinical MRI or CT scan. Deformable image registration is a useful tool in other areas such as adaptive radiotherapy, where the radiation oncology team monitors patients during the course of treatment and adjusts the radiation treatments if necessary when the patient anatomy changes. Deformable image registration is used in this setting, but there is a considerable level of uncertainty. This work represents one of many possible approaches at investigating the nature of these uncertainties utilizing consistency metrics. We will show that metrics such as the inverse consistency error correlate with actual registration uncertainties. Specifically relating to brain metastases, this work investigates where in the brain metastases are likely to form, and how the primary cancer site is related. We will show that the cerebellum is at high risk for metastases and that non-uniform dose distributions may be advantageous when delivering prophylactic cranial irradiation for patients with small cell lung cancer in complete remission.

  1. Stable chromosome aberrations in the reconstruction of radiation doses

    International Nuclear Information System (INIS)

    Chromosome-type aberrations, such as dicentric and translocation chromosomes, are biomarkers of exposure to ionizing radiation. So far, analysis of dicentric chromosomes in peripheral blood lymphocytes has been the only method routinely used in biological dose assessment. During division of T cell precursors, proliferative death of cells containing dicentric chromosomes reduces the number of such lymphocytes in peripheral blood. Dicentrics are thus suitable for dose calculations during a reasonably short period after exposure to radiation. Unlike dicentrics, translocations persist in cell division and enable dose estimation over long time periods following exposure. A recent development in molecular biology, the FISH (fluorescence in situ hybridization) chromosome-painting technique, has opened the possibility for accurate recognition of translocations and thus retrospective determination of dose. The purpose of the present study was to evaluate the applicability of translocation analysis by means of FISH chromosome painting for retrospective dosimetry. In the construction of acute dose-effect curves for 60Co g-ray-induced chromosomal aberrations using FISH chromosome painting, translocations showed a linear-quadratic relationship to dose, similar to that seen in dicentrics. Donor-dependent translocation frequencies at control level and at low doses were observed. The linear part of the calibration curve for two way translocations, i.e. both translocation chromosomes present, proved to be more reliable than the comparable low-dose response for total translocations, which include both two- and one-way translocations. The results indicate that the linear part of the curve requires precise determination, particularly since application of the technique will probably cover mainly chronically exposed subjects. An opportunity to gain direct information on translocation persistence over time was opened by obtaining repeated samples from subjects accidentally exposed to

  2. Hawking's radiation in non-stationary rotating de Sitter background

    CERN Document Server

    Ibohal, Ng; 10.1007/s10509-011-0606-0

    2011-01-01

    Hawking's radiation effect of Klein-Gordon scalar field, Dirac particles and Maxwell's electromagnetic field in the non-stationary rotating de Sitter cosmological space-time is investigated by using a method of generalized tortoise co-ordinates transformation. The locations and the temperatures of the cosmological horizons of the non-stationary rotating de Sitter model are derived. It is found that the locations and the temperatures of the rotating cosmological model depend not only on the time but also on the angle. The stress-energy regularization techniques are applied to the two dimensional analog of the de Sitter metrics and the calculated stress-energy tensor contains the thermal radiation effect.

  3. Radiological mapping of Kelantan, Malaysia, using terrestrial radiation dose rate.

    Science.gov (United States)

    Garba, Nuraddeen Nasiru; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Sanusi, Syazwan Mohd; Gabdo, Hamman Tukur

    2016-06-01

    Measurements of the environmental terrestrial gamma radiation dose rate (TGRD) in each district of Kelantan state, Malaysia, were carried out using a portable hand-held radiation survey meter and global positioning system. The measurements were done based on geology and soil types of the area. The mean TGRD was found to be 209 nGy h(-1). Few areas of relatively enhanced activity were observed in Pasir Mas, Tanah Merah and Jeli districts, which have a mean TGRD between 300 and 500 nGy h(-1). An isodose map of the area was produced using ArcGIS software version 9.3. PMID:26540360

  4. Radiological mapping of Kelantan, Malaysia, using terrestrial radiation dose rate.

    Science.gov (United States)

    Garba, Nuraddeen Nasiru; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Sanusi, Syazwan Mohd; Gabdo, Hamman Tukur

    2016-06-01

    Measurements of the environmental terrestrial gamma radiation dose rate (TGRD) in each district of Kelantan state, Malaysia, were carried out using a portable hand-held radiation survey meter and global positioning system. The measurements were done based on geology and soil types of the area. The mean TGRD was found to be 209 nGy h(-1). Few areas of relatively enhanced activity were observed in Pasir Mas, Tanah Merah and Jeli districts, which have a mean TGRD between 300 and 500 nGy h(-1). An isodose map of the area was produced using ArcGIS software version 9.3.

  5. Predicted effects of countermeasures on radiation doses from contaminated food

    International Nuclear Information System (INIS)

    Quantitative assessments of the effects on radiation-dose reductions from nine typical countermeasures against accidental fod contamination have been carried out with dynamic radioecological models. The foodstuffs are assumed to be contaminated with iodine-131, caesium-134 and caesium-137 after a release of radioactive materials from the Ringhals nuclear power station in Sweden resulting from a hypothetical core melt accident. The release of activity of these radionuclides is assumed at 0.07% of the core inventory of the unit 1 reactor (1600 TBq of I-131, 220 TBq of Cs-134 and 190 TBq of Cs-137). Radiation doses are estimated for the 55,000 affected inhabitants along the south-eastern coast of Sweden eating locally produced foodstuffs. The average effective dose equivalent to an individual in the critical group is predicted to be 2.9 mSv from food consumption contaminated with I-131. An accident occurring during winter is estimated to cause average individual doses of 0.32 mSv from Cs-134 and 0.47 mSv from Cs-137, and 9.4 mSv and 6.8 mSv from Cs-134 and Cs-137, respectively, for an accident occurring during summer. Doses from the intake of radioiodine may be reduced by up to a factor of 60 by rejecting contaminated food for 30 days. For the doses from radiocaesium, the largest effect is found form deep ploughing which may reduce the dose by up to a factor of 80. (au) (12 tabs., 6 ills., 19 refs.)

  6. Detecting a non-Gaussian stochastic background of gravitational radiation

    CERN Document Server

    Drasco, S; Drasco, Steve; Flanagan, Eanna E.

    2002-01-01

    We derive a detection method for a stochastic background of gravitational waves produced by events where the ratio of the average time between events to the average duration of an event is large. Such a signal would sound something like popcorn popping. Our derivation is based on the somewhat unrealistic assumption that the duration of an event is smaller than the detector time resolution.

  7. Detecting a non-Gaussian stochastic background of gravitational radiation

    OpenAIRE

    Drasco, Steve; Flanagan, Eanna E.

    2001-01-01

    We derive a detection method for a stochastic background of gravitational waves produced by events where the ratio of the average time between events to the average duration of an event is large. Such a signal would sound something like popcorn popping. Our derivation is based on the somewhat unrealistic assumption that the duration of an event is smaller than the detector time resolution.

  8. Excess cancer risk among inhabitants in the high background radiation area of Yangjiang, China (1979-1998)

    International Nuclear Information System (INIS)

    The mortality among the inhabitants in the high background radiation area (HBRA) of Yangjiang, Guangdong Province, China was first reported internationally in 1980. Most of the inhabitants lived in the study areas for six or more generations. External radiation dose from the natural sources, including thorium, was estimated to be 2.10 mSv/a in the HBRA and 0.77 mSv/a in the control area (CA). Regarding internal radiation exposure, it was estimated that internal radiation doses in the HBRA and the CA were 4.27 mSv/a and 1.65 mSv/a, respectively. The epidemiological studies had failed to show any excess risk of cancer. The major purpose of the present study is to evaluate the effects of continuous low dose-rate exposure to low-linear energy transfer (LET) ionizing radiation on excess cancer risk. In this report, we present the results of cancer mortality analysis during the period 1979-1998, adding 3 years to the previous reports. (author)

  9. Dose conversion factors for radiation doses at normal operation discharges. F. Methods report

    International Nuclear Information System (INIS)

    A study has been performed in order to develop and extend existing models for dose estimations at emissions of radioactive substances from nuclear facilities in Sweden. This report gives a review of the different exposure pathways that have been considered in the study. Radioecological data that should be used in calculations of radiation doses are based on the actual situation at the nuclear sites. Dose factors for children have been split in different age groups. The exposure pathways have been carefully re-examined, like the radioecological data; leading to some new pathways (e.g. doses from consumption of forest berries, mushrooms and game) for cesium and strontium. Carbon 14 was given a special treatment by using a model for uptake of carbon by growing plants. For exposure from aquatic emissions, a simplification was done by focussing on the territory for fish species, since consumption of fish is the most important pathway

  10. Towards individualized dose constraints: Adjusting the QUANTEC radiation pneumonitis model for clinical risk factors

    DEFF Research Database (Denmark)

    Appelt, Ane L; Vogelius, Ivan R.; Farr, Katherina P.;

    2014-01-01

    factors, in order to enable individual risk prediction. The approach is validated in an independent dataset. Material and methods. The prevalence of risk factors in the patient populations underlying the QUANTEC analysis was estimated, and a previously published method to adjust dose......-response relationships for clinical risk factors was employed. Effect size estimates (odds ratios) for risk factors were drawn from a recently published meta-analysis. Baseline values for D50 and γ50 were found. The method was tested in an independent dataset (103 patients), comparing the predictive power of the dose......Background. Understanding the dose-response of the lung in order to minimize the risk of radiation pneumonitis (RP) is critical for optimization of lung cancer radiotherapy. We propose a method to combine the dose-response relationship for RP in the landmark QUANTEC paper with known clinical risk...

  11. Radiation dose and radiation risk to foetuses and newborns during X-ray examinations

    International Nuclear Information System (INIS)

    The purpose of this study is to determine the way in which the demands set by degree 423/2000 by the Ministry of Social Affairs and Health are fulfilled with respect to the most radiosensitive groups, the foetus and the child, by estimating the radiation dose and radiation risk to the foetus from x-ray examinations of an expectant mother's pelvic region, finding out the practice involved in preventing doses to embryos and foetuses and assessing dose practices in cases where an embryo or foetus is or shall be exposed, and by estimating radiation dose and risk due to the radiation received by a new-born being treated in a paediatric intensive care unit. No statistics are available in Finland to indicate how many x-ray examinations of the pelvic region and lower abdomen are made to pregnant patients or to show the dose and risk to the foetus due these examinations. In order to find out the practices in radiological departments concerning the pelvic x-ray examination of fertile woman and the number of foetuses exposed, a questionnaire was sent to all radiation safety officers responsible for the safe use of radiation (n = 290). A total of 173 questionnaires were returned. This study recorded the technique and Dose-Area Product of 118 chest examinations of newborns in paediatric intensive care units. Entrance surface doses and effective doses were calculated separately to each newborn. Based on the patient records, the number of all x-ray examinations during the study was calculated and the effective doses were estimated retrospectively to each child. The radiation risk was estimated both for the foetuses and for the newborns. According to this study, it is rare in Finland to expose a pregnant woman to radiation. On the other hand, with the exception of pelvimetry examinations, there are no compiled statistics concerning the number of pelvic x-ray examinations of a pregnant woman. There was no common practice on how to exclude the possibility of pregnancy. The dose to a

  12. Radiation dose and radiation risk to foetuses and newborns during X-ray examinations

    Energy Technology Data Exchange (ETDEWEB)

    Kettunen, A. [Oulu Univ. (Finland)

    2004-05-01

    The purpose of this study is to determine the way in which the demands set by degree 423/2000 by the Ministry of Social Affairs and Health are fulfilled with respect to the most radiosensitive groups, the foetus and the child, by estimating the radiation dose and radiation risk to the foetus from x-ray examinations of an expectant mother's pelvic region, finding out the practice involved in preventing doses to embryos and foetuses and assessing dose practices in cases where an embryo or foetus is or shall be exposed, and by estimating radiation dose and risk due to the radiation received by a new-born being treated in a paediatric intensive care unit. No statistics are available in Finland to indicate how many x-ray examinations of the pelvic region and lower abdomen are made to pregnant patients or to show the dose and risk to the foetus due these examinations. In order to find out the practices in radiological departments concerning the pelvic x-ray examination of fertile woman and the number of foetuses exposed, a questionnaire was sent to all radiation safety officers responsible for the safe use of radiation (n = 290). A total of 173 questionnaires were returned. This study recorded the technique and Dose-Area Product of 118 chest examinations of newborns in paediatric intensive care units. Entrance surface doses and effective doses were calculated separately to each newborn. Based on the patient records, the number of all x-ray examinations during the study was calculated and the effective doses were estimated retrospectively to each child. The radiation risk was estimated both for the foetuses and for the newborns. According to this study, it is rare in Finland to expose a pregnant woman to radiation. On the other hand, with the exception of pelvimetry examinations, there are no compiled statistics concerning the number of pelvic x-ray examinations of a pregnant woman. There was no common practice on how to exclude the possibility of pregnancy. The dose

  13. 85Kr management trade-offs: a perspective to total radiation dose commitment

    Energy Technology Data Exchange (ETDEWEB)

    Mellinger, P.J.; Hoenes, G.R.; Brackenbush, L.W.; Greenborg, J.

    1980-01-01

    Radiological consequences arising from the trade-offs for /sup 85/Kr waste management from possible nuclear fuel resource recovery activities have been investigated. The reference management technique is to release all the waste gas to the atmosphere where it is diluted and dispersed. A potential alternative is to collect, concentrate, package and submit the gas to long-term storage. This study compares the radiation dose commitment to the public and to the occupationally exposed work force from these alternatives. The results indicate that it makes little difference to the magnitude of the world population dose whether /sup 85/Kr is captured and stored or chronically released to the environment. Further, comparisons of radiation exposures (for the purpose of estimating health effects) at very low dose rates to very large populations with exposures to a small number of occupationally exposed workers who each receive much higher dose rates may be misleading. Finally, cost studies (EPA 1976 and DOE 1979a) show that inordinate amounts of money will be required to lower this already extremely small 80-year cumulative world population dose of 0.05 mrem/person (<0.001% of natural background radiation for the same time period).

  14. Low doses of ionizing radiation: Biological effects and regulatory control. Invited papers and discussions. Proceedings of an international conference

    International Nuclear Information System (INIS)

    The levels and biological effects resulting from exposure to ionizing radiation are continuously reviewed by the United Nations Committee on the Effects of Atomic Radiation (UNSCEAR). Since its creation in 1928, the International Commission on Radiological Protection (ICRP) has issued recommendations on protection against ionizing radiation. The UNSCEAR estimates and the ICRP recommendations have served as the basis for national and international safety standards on radiation safety, including those developed by the International Atomic Energy Agency (IAEA) and the World Health Organization (WHO). Concerning health effects of low doses of ionizing radiation, the international standards are based on the plausible assumption that, above the unavoidable background radiation dose, the probability of effects increases linearly with dose, i.e. on a 'linear, no threshold' (LNT) assumption. However, in recent years the biological estimates of health effects of low doses of ionizing radiation and the regulatory approach to the control of low level radiation exposure have been much debated. To foster information exchange on the relevant issues, an International Conference on Low Doses of Ionizing Radiation: Biological Effects and Regulatory Control, jointly sponsored by the IAEA and WHO in co-operation with UNSCEAR, was held from 17-21 November 1997 at Seville, Spain. These Proceedings contain the invited special reports, keynote papers, summaries of discussions, session summaries and addresses presented at the opening and closing of the Conference

  15. Patient radiation dose audits for fluoroscopically guided interventional procedures

    Energy Technology Data Exchange (ETDEWEB)

    Balter, Stephen; Rosenstein, Marvin; Miller, Donald L.; Schueler, Beth; Spelic, David [Department of Radiology and Department of Medicine, Columbia University, New York, New York 10032 (United States); Clarksburg, Maryland 20871 (United States); Department of Radiology, F. Edward Hebert School of Medicine, Uniformed Services University, Bethesda, Maryland 20814 (United States); Department of Radiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905 (United States); Division of Mammography Quality and Radiation Programs, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20903 (United States)

    2011-03-15

    Purpose: Quality management for any use of medical x-ray imaging should include monitoring of radiation dose. Fluoroscopically guided interventional (FGI) procedures are inherently clinically variable and have the potential for inducing deterministic injuries in patients. The use of a conventional diagnostic reference level is not appropriate for FGI procedures. A similar but more detailed quality process for management of radiation dose in FGI procedures is described. Methods: A method that takes into account both the inherent variability of FGI procedures and the risk of deterministic injuries from these procedures is suggested. The substantial radiation dose level (SRDL) is an absolute action level (with regard to patient follow-up) below which skin injury is highly unlikely and above which skin injury is possible. The quality process for FGI procedures collects data from all instances of a given procedure from a number of facilities into an advisory data set (ADS). An individual facility collects a facility data set (FDS) comprised of all instances of the same procedure at that facility. The individual FDS is then compared to the multifacility ADS with regard to the overall shape of the dose distributions and the percent of instances in both the ADS and the FDS that exceed the SRDL. Results: Samples of an ADS and FDS for percutaneous coronary intervention, using the dose metric of reference air kerma (K{sub a,r}) (i.e., the cumulative air kerma at the reference point), are used to illustrate the proposed quality process for FGI procedures. Investigation is warranted whenever the FDS is noticeably different from the ADS for the specific FGI procedure and particularly in two circumstances: (1) When the facility's local median K{sub a,r} exceeds the 75th percentile of the ADS and (2) when the percent of instances where K{sub a,r} exceeds the facility-selected SRDL is greater for the FDS than for the ADS. Conclusions: Analysis of the two data sets (ADS and FDS

  16. Evaluation of Background Ionization Radiation Level in some selected Dumpsites in Delta State, Nigeria

    OpenAIRE

    Avwiri, O Gregory; Emmanuel, O Esi

    2014-01-01

    This paper reports on the evaluation of background Ionization radiation level (BIR) in some selected Dumpsites in Uvwie, Udu and Ughelli North Local government area of Delta State, Nigeria. Background ionization radiation measurements were carried out in five Dumpsites. An in- situ measurement was done using a well calibrated nuclear radiation meters Radalert-100 and a geographical positioning system (GPS). Readings were taken once in a week for one month in ten different locations within eac...

  17. The efects of low-dose ionizing radiation on angiogenesis

    OpenAIRE

    Oliveira, Inês Sofia Batista Vala Silva de, 1981-

    2011-01-01

    Tese de doutoramento, Biologia (Biologia Celular), Universidade de Lisboa, Faculdade de Ciências, 2011 Angiogenesis is the formation of new blood vessels from pre‐existing ones. This process is regulated by a balance between pro‐ and anti‐angiogenic molecules and is derailed in various diseases, such as cancer. Radiotherapy is a commonly‐used treatment for cancer. However, recent studies suggest that ionizing radiation (IR) doses delivered inside the tumor target volume during fractionated...

  18. Single-Dose Radiation-Induced Oral Mucositis Mouse Model

    Science.gov (United States)

    Maria, Osama Muhammad; Syme, Alasdair; Eliopoulos, Nicoletta; Muanza, Thierry

    2016-01-01

    The generation of a self-resolved radiation-induced oral mucositis (RIOM) mouse model using the highest possibly tolerable single ionizing radiation (RT) dose was needed in order to study RIOM management solutions. We used 10-week-old male BALB/c mice with average weight of 23 g for model production. Mice were treated with an orthovoltage X-ray irradiator to induce the RIOM ulceration at the intermolar eminence of the animal tongue. General anesthesia was injected intraperitoneally for proper animal immobilization during the procedure. Ten days after irradiation, a single RT dose of 10, 15, 18, 20, and 25 Gy generated a RIOM ulcer at the intermolar eminence (posterior upper tongue surface) with mean ulcer floor (posterior epithelium) heights of 190, 150, 25, 10, and 10 μm, respectively, compared to 200 μm in non-irradiated animals. The mean RIOM ulcer size % of the total epithelialized upper surface of the animal tongue was RT dose dependent. At day 10, the ulcer size % was 2, 5, 27, and 31% for 15, 18, 20, and 25 Gy RT, respectively. The mean relative surface area of the total epithelialized upper surface of the tongue was RT dose dependent, since it was significantly decreased to 97, 95, 88, and 38% with 15, 18, 20, and 25 Gy doses, respectively, at day 10 after RT. Subcutaneous injection of 1 mL of 0.9% saline/6 h for 24 h yielded a 100% survival only with 18 Gy self-resolved RIOM, which had 5.6 ± 0.3 days ulcer duration. In conclusion, we have generated a 100% survival self-resolved single-dose RIOM male mouse model with long enough duration for application in RIOM management research. Oral mucositis ulceration was radiation dose dependent. Sufficient hydration of animals after radiation exposure significantly improved their survival. PMID:27446800

  19. Development of a mid-head radiation dose response function

    International Nuclear Information System (INIS)

    Calculations have been made of the incident neutron and gamma-ray absorbed dose response as a function of energy in the mid-head position of a phantom model. The calculations were performed with the DOT discrete ordinates transport code in the adjoint mode using co-axial cylinders to represent the head and torso. Results, given in a coupled 37-neutron-group, 21-gamma-ray-group structure (37/21) and a 22-neutron-group, 18-gamma-ray-group structure (22/18), are compared with previously obtained results. The mid-head response is less than the conventional radiation protection fluence-to-dose factors which are based on maximum phantom values. In the case of a fission source in air the neutron dose is about a factor of 4 less, and the secondary gamma-ray dose is about a factor of 1.5 less. For a fusion source the neutron dose ratio varies from about 1.9 at close range to about 3. The gamma-ray dose ratio is about the same as for the fission source. Tables of the various response functions are presented in the Appendix A

  20. Patient absorbed radiation doses estimation related to irradiation anatomy

    International Nuclear Information System (INIS)

    Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector

  1. How do we face low-dose radiation exposure

    International Nuclear Information System (INIS)

    Radio-contamination caused by Fukushima Daiichi Nuclear Power Plant Accident has spread to wide areas of the Prefecture and the present radiation level even in its capital Fukushima City is around 1 micro-Sv/h, 20 times as high as the past before the Accident. Japanese Government defines that the level <20 mSv/y is not hazardous to human health but residents always feel uneasiness. This paper describes about radiation problems present in administrative guidance from the scientific view. There are 3 different opinions about the health hazard of low dose exposure of <100 mSv/y: no influence, lower risk corresponding to lower dose (linear no threshold theory), and not always lower risk corresponding to lower dose. These are scientifically uncertain, and safety for radiation cannot be easily defined. Additional dose limit defined by Administration is 1 mSv/y for general public, to which compliance should be thought to be a prerequisite condition. The project of Fukushima Health Management Survey should be conducted in order to lessen the unnecessary exposure dose of residents as one of its aims. The most effective decontamination means are unknown at present, and therefore, whether the level of <1 mSv/y is attainable by decontamination of areas exceeding this is unknown. As seeable in easily declared safety of rice, people should not be overconfident in systems for monitoring urgently established after the accident. Three risk advisers invited by the Prefecture are saying that unnecessary exposure should be avoided, despite that they have the opinion of null risk at <100 mSv/y. The author comments that as the limited, insufficient information is said to lead the public to anxiety, confusion and finally panic, the Administration should not take a willful attitude tending to safety. (T.T.)

  2. Distribution of terrestrial gamma radiation dose rate in the eastern coastal area of Odisha, India.

    Science.gov (United States)

    Gusain, G S; Rautela, B S; Sahoo, S K; Ishikawa, T; Prasad, G; Omori, Y; Sorimachi, A; Tokonami, S; Ramola, R C

    2012-11-01

    Terrestrial gamma radiation is one of the important radiation exposures on the earth's surface that results from the three primordial radionuclides (226)Ra, (232)Th and (40)K. The elemental concentration of these elements in the earth's crust could result in the anomalous variation of the terrestrial gamma radiation in the environment. The geology of the local area plays an important role in distribution of these radioactive elements. Environmental terrestrial gamma radiation dose rates were measured around the eastern coastal area of Odisha with the objective of establishing baseline data on the background radiation level. The values of the terrestrial gamma radiation dose rate vary significantly at different locations in the study area. The values of the terrestrial gamma dose rate ranged from 77 to 1651 nGy h(-1), with an average of 230 nGy h(-1). During the measurement of the terrestrial gamma dose rate, sand and soil samples were also collected for the assessment of natural radionuclides. The activities of (226)Ra, (232)Th and (40)K from these samples were measured using a gamma-ray spectrometry with a NaI(Tl) detector. Activity concentrations of (226)Ra, (232)Th and (40)K ranged from 15.6 to 69 Bq kg(-1) with an average of 46.7 Bq kg(-1), from 28.9 to 973 Bq kg(-1) with an average of 250 Bq kg(-1) and from 139 to 952 Bq kg(-1) with an average of 429, respectively. The detailed significance of these studies has been discussed from the radiation protection point of view. PMID:22874894

  3. Radiation dose in radiotherapy from prescription to delivery

    International Nuclear Information System (INIS)

    Cancer incidence is increasing in developed as well as in developing countries. Cancer may be expected to become a prominent problem and this will result in public pressure for higher priorities on cancer care. In some relatively advanced developing countries radiation therapy is applied in about 50% of all detected cancer cases. Approximately half of these treatments have curative intent. Surgery and radiotherapy applied individually or combined result in the cure of about 40% of all patients. The application of chemotherapy alone has curative effects only on a small percentage of cancer patients. It is encouraging to note that the results achieved by radiation therapy show continuous improvement. This can be traced back to a number of developments: increased knowledge regarding tumour and normal tissue response to radiation, early diagnosis with improved tumour localisation, improved dosimetry and dose planning. The introduction of modern equipment has been crucial in these developments and makes possible a more accurate target delineation, better treatment planning resulting in irradiation of the Planning Target Volume (PTV) with a highly uniform dose and, simultaneously, a reduction in dose to healthy tissues outside the PTV. Experience shows that high quality radiotherapy can only be achieved if its conducted by a skilled team working closely together with good communication between various categories of staff. Therefore, seminars and training courses covering all aspects of radiotherapy and dosimetry are of great importance and should be held regionally or nationally on a regular basis. Refs, figs, tabs

  4. Radiation-Induced Leukemia at Doses Relevant to Radiation Therapy: Modeling Mechanisms and Estimating Risks

    Science.gov (United States)

    Shuryak, Igor; Sachs, Rainer K.; Hlatky, Lynn; Mark P. Little; Hahnfeldt, Philip; Brenner, David J.

    2006-01-01

    Because many cancer patients are diagnosed earlier and live longer than in the past, second cancers induced by radiation therapy have become a clinically significant issue. An earlier biologically based model that was designed to estimate risks of high-dose radiation induced solid cancers included initiation of stem cells to a premalignant state, inactivation of stem cells at high radiation doses, and proliferation of stem cells during cellular repopulation after inactivation. This earlier model predicted the risks of solid tumors induced by radiation therapy but overestimated the corresponding leukemia risks. Methods: To extend the model to radiation-induced leukemias, we analyzed in addition to cellular initiation, inactivation, and proliferation a repopulation mechanism specific to the hematopoietic system: long-range migration through the blood stream of hematopoietic stem cells (HSCs) from distant locations. Parameters for the model were derived from HSC biologic data in the literature and from leukemia risks among atomic bomb survivors v^ ho were subjected to much lower radiation doses. Results: Proliferating HSCs that migrate from sites distant from the high-dose region include few preleukemic HSCs, thus decreasing the high-dose leukemia risk. The extended model for leukemia provides risk estimates that are consistent with epidemiologic data for leukemia risk associated with radiation therapy over a wide dose range. For example, when applied to an earlier case-control study of 110000 women undergoing radiotherapy for uterine cancer, the model predicted an excess relative risk (ERR) of 1.9 for leukemia among women who received a large inhomogeneous fractionated external beam dose to the bone marrow (mean = 14.9 Gy), consistent with the measured ERR (2.0, 95% confidence interval [CI] = 0.2 to 6.4; from 3.6 cases expected and 11 cases observed). As a corresponding example for brachytherapy, the predicted ERR of 0.80 among women who received an inhomogeneous low-dose

  5. Ionizing Radiation Dose Due to the Use of Agricultural Fertilizers

    International Nuclear Information System (INIS)

    The transference of radionuclides from the fertilizers to/and from soils to the foodstuffs can represent an increment in the internal dose when the vegetables are consumed by the human beings. This work evaluates the contribution of fertilizers to the increase of radiation level in the environment and of dose to the people. Samples of fertilizers, soils and vegetables produced in farms located in the neighbourhood of Sao Paulo city in the State of Sao Paulo, Brazil were analysed through gamma spectroscopy. The values of specific activity of 40K, 238U and 232Th show that there is no significant transference of natural radionuclides from fertilizers to the final product of the food chain. The annual committed effective dose due to the ingestion of 40K contained in the group of consumed vegetables analysed in this work resulted in the very low value of 0.882 μSv

  6. Dose monitor chamber for electron or x-ray radiation

    International Nuclear Information System (INIS)

    This invention relates to a dose monitor chamber for electron or X-ray radiation, preferably for use in conjunction with a linear accelerator. The dose monitor chamber comprises two measuring electrodes. The first electrode is essentially a ring portion which at its circumference extends from 0 degrees to approximately 180 degrees. The second electrode is located in the same plane as the first electrode. It comprises a full inner circular area to the periphery of which a second ring portion adjoins in an electrically conducting manner. The measuring electrodes are electrically insulated from each other. They are preferably thin electrically-conductive layers affixed to an insulating material. With such a dose monitor chamber, two electrical signals can be obtained, each produced by one electrode. Both symmetry signals and flatness signals may be obtained

  7. Cone beam computed tomography radiation dose and image quality assessments.

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  8. Response of pig skin to fractionated radiation doses

    International Nuclear Information System (INIS)

    The individual components of a fractionated course of irradiation treatment have been considered separately. Methods of accurate measurement of individual parameters has brought to light different interpretations of the observations. Reasons are given for the necessity of having a radiobiological model which has a direct relevance to the clinical situation. Results are reported for fractionated regimes of irradiation in which the dose has been varied above and below normal tissue tolerance which has been equated with clinical skin necrosis. The components of the acute skin reaction, erythema, pigmentation and desquamation have been analysed separately and their contribution as a method of measurement assessed. Initially, the range of numerical scores attributed to erythema did not reach the scores attributed to necrosis but we now believe that radiation damage expressed as erythema can move directly into necrosis without passing through desquamation. Desquamation, on the other hand, only became a useful parameter at higher dose levels; it has also been shown to be a component associated with skin breakdown. Pigmentation showed no dose response at the dose levels employed in our experiments and it is our belief that this is due to this system being fully saturated under these circumstances. Measurement of the late radiation reaction in the skin has been considered in detail and our results have been expressed by comparing the relative lengths of irradiated and control fields in the same pig. From these findings iso-effect graphs have been constructed and time and fractionation factors have been derived. (author)

  9. Radiation dose reduction in direct digital panoramic radiography

    Energy Technology Data Exchange (ETDEWEB)

    Gavala, Sophia; Donta, Catherine [Department of Oral Diagnosis and Oral Radiology, School of Dentistry, University of Athens, 2 Thivon Street Goudi, 115 27 Athens (Greece); Tsiklakis, Kostas [Department of Oral Diagnosis and Oral Radiology, School of Dentistry, University of Athens, 2 Thivon Street Goudi, 115 27 Athens (Greece)], E-mail: ktsiklak@dent.uoa.gr; Boziari, Argyro; Kamenopoulou, Vasiliki [Greek Atomic Energy Commission (Greece); Stamatakis, Harry C. [Department of Oral Diagnosis and Oral Radiology, School of Dentistry, University of Athens, 2 Thivon Street Goudi, 115 27 Athens (Greece)

    2009-07-15

    Objectives: (a) To measure the absorbed radiation doses at 16 anatomical sites of a Rando phantom and (b) to calculate the effective doses including and excluding the salivary gland doses in panoramic radiography using a conventional and a digital panoramic device. Study design: Thermoluminescent dosimeters (TLD-100) were placed at 16 sites in a Rando phantom, using a conventional, Planmeca Promax and a digital, Planmeca PM2002CC Proline 2000 (Planmeca Oy, 00880 Helsinki, Finland) panoramic device for panoramic radiography. During conventional radiography the selected exposure settings were 66 kVp, 6 mA and 16 s, while during digital radiography two combinations were selected 60 kVp, 4 mA, 18 s and 66 kVp, 8 mA, 18 s with and without image processing function. The dosimeters were annealed in a PTW-TLDO Harshaw oven. TLD energy response was studied using RQN beam narrow series at GAEC's Secondary Standard Calibration Laboratory. The reader used was a Harshaw, 4500. Effective dose was estimated according to ICRP{sub 60} report (E{sub ICRP60}). An additional estimation of the effective dose was accomplished including the doses of the salivary glands (E{sub SAL}). A Wilcoxon signed ranks test was used for statistical analysis. Results: The effective dose, according to ICRP report (E{sub ICRP60}) in conventional panoramic radiography was 17 {mu}Sv and E{sub SAL} was 26 {mu}Sv. The respective values in digital panoramic radiography were E{sub ICRP60} = 23 {mu}Sv and E{sub SAL} = 38 {mu}Sv; while using the lowest possible radiographic settings E{sub ICRP60} was 8 {mu}Sv and E{sub SAL} was 12 {mu}Sv. Conclusions: The effective dose reduction in digital panoramic radiography can be achieved, if the lowest possible radiographic settings are used.

  10. Optimization of radiation dosing schedules for proneural glioblastoma.

    Science.gov (United States)

    Badri, H; Pitter, K; Holland, E C; Michor, F; Leder, K

    2016-04-01

    Glioblastomas are the most aggressive primary brain tumor. Despite treatment with surgery, radiation and chemotherapy, these tumors remain uncurable and few significant increases in survival have been observed over the last half-century. We recently employed a combined theoretical and experimental approach to predict the effectiveness of radiation administration schedules, identifying two schedules that led to superior survival in a mouse model of the disease (Leder et al., Cell 156(3):603-616, 2014). Here we extended this approach to consider fractionated schedules to best minimize toxicity arising in early- and late-responding tissues. To this end, we decomposed the problem into two separate solvable optimization tasks: (i) optimization of the amount of radiation per dose, and (ii) optimization of the amount of time that passes between radiation doses. To ensure clinical applicability, we then considered the impact of clinical operating hours by incorporating time constraints consistent with operational schedules of the radiology clinic. We found that there was no significant loss incurred by restricting dosage to an 8:00 a.m. to 5:00 p.m. window. Our flexible approach is also applicable to other tumor types treated with radiotherapy. PMID:26094055

  11. Dietary intake of naturally occurring radionuclides from thorium series, uranium series and potassium-40 in high background radiation areas of Manavalakurichi, Tamil Nadu

    International Nuclear Information System (INIS)

    Natural background radiation is a major source of human exposure to radiation. The source of background radiation is due to monazite containing naturally occurring radionuclides like thorium and uranium. These natural radionuclides are found in all environmental matrices like rocks, soil, water, and dietary sources. The intake of natural radionuclides to public would occur in ingestion pathway via dietary sources. The present study aims to evaluate the natural radionuclides in dietary sources from Manavalakurichi region, which is a High Background Radiation Area's (HBRA's) in Tamil Nadu. The natural radionuclides such as Uranium (238U and 234U), Radium (226Ra and 228Ra), Polonium (210Po) and Potassium (40K) in the dietary products were analyzed in various dietary sources and computed the ingestion dose for different age group of public residing in and around Manavalakurichi. The study can act as existing data for Indian population living in the high radiation background areas

  12. Radiation dose and subsequent risk for stomach cancer in long-term survivors of cervical cancer

    DEFF Research Database (Denmark)

    Kleinerman, Ruth A; Smith, Susan A; Holowaty, Eric;

    2013-01-01

    To assess the dose-response relationship for stomach cancer after radiation therapy for cervical cancer.......To assess the dose-response relationship for stomach cancer after radiation therapy for cervical cancer....

  13. Dark energy and the cosmic microwave background radiation

    Science.gov (United States)

    Dodelson, S.; Knox, L.

    2000-01-01

    We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe.

  14. Fast shutter for low background radiation environments at SPR III

    International Nuclear Information System (INIS)

    A fast shutter system has been developed and used to isolate experiments from the radiation emitted after the main pulse of the Sandia Pulse Reactor, SPR 3. In about 15 ms the system moves a massive 20 kg shield in front of the beam port aperture in the facility shield wall. A second gravity-driven shutter is dropped into place in about 200 ms. The total attenuation achieved in the beam intensity is about a factor of one hundred. The shutter assembly was used, along with a sensitive detection system, to observe the gamma ray flux emitted by various materials activated by the neutron beam at levels nine orders of magnitude smaller than the gamma flux level at the target during the reactor pulse

  15. Even low doses of radiation lead to DNA damage accumulation in lung tissue according to the genetically-defined DNA repair capacity

    International Nuclear Information System (INIS)

    Background and purpose: Intensity-modulated radiation therapy for thoracic malignancies increases the exposure of healthy lung tissue to low-dose radiation. The biological impact of repetitive low-dose radiation on the radiosensitive lung is unclear. Materials and methods: In the present study, using mouse strains with different genetic DNA repair capacities, we monitored the extent of DNA damage in lung parenchyma after 2, 4, 6, 8, and 10 weeks of daily low-dose 100-mGy radiation. Results: Using 53BP1 as a marker for double-strand breaks, we observed DNA damage accumulation during fractionated low-dose radiation with increasing cumulative doses. The amount of radiation-induced 53BP1 varied significantly between bronchiolar and alveolar epithelial cells, suggesting that different cell populations in the lung parenchyma had varying vulnerabilities to ionizing radiation. The genetic background of DNA repair determined the extent of cumulative low-dose radiation damage. Moreover, increased DNA damage during fractionated low-dose radiation affected replication, and apoptosis in the lung parenchyma, which may influence overall lung function. Conclusion: Collectively, our results suggest that low, yet damaging, doses of radiation increase the risk of toxicity to normal lung tissue and the probability of developing secondary malignancies

  16. Applicability of the tissue stem cell turnover concept on the validity of cumulative dose based radiation risk evaluation

    International Nuclear Information System (INIS)

    The radiation protection system adopts the linear no-threshold model to achieve proper radiation protection for considering cancer risks resulting from radiation exposure. This model uses cumulative dose to a tissue for risk evaluation in which cumulative dose is related to the amount of DNA damage and consequential induction of gene mutation. In this concept, gene mutation accumulates in tissue stem cells, the putative target of carcinogenesis, with total dose given to the tissue. Unlike high-dose-rate exposure, epidemiological studies in high radiation background areas, such as Kerala in India, revealed that cancer risks is not elevated by the dose to the inhabitants, suggesting that there exists some mechanisms to eliminate the damage/mutation in the exposed tissue under extremely low-dose-rate exposure situations. In this report, the dynamics of tissue stem cell turnover is evaluated as a possible mechanism under extremely low-dose-rate exposure situations. To this end, we reviewed recent literatures studying tissue stem cell turnover, and found that great advances in stem cell research have made it possible to trace a fate of stem cells in tissues. Furthermore, turnover of tissue stem cells is found to occur after irradiation, due to competition of stem cells within tissues. This raises a possibility that radiation effects may not accumulate in a tissue depending on the dose-rate and duration of exposure period. (author)

  17. THE BACKGROUND RADIATION AND EXPOSURE LEVELS AT VARIOUS SOUTH AFRICAN WEST COAST MILITARY UNITS

    Directory of Open Access Journals (Sweden)

    Jacques Bezuidenhout

    2014-11-01

    Full Text Available The West Coast of South Africa between St Helena Bay to the north and Langebaan Lagoon to the south is characterised by numerous granite protrusions. These outcrops are elements of the underlying Cape Granite Suite, which forms the bedrock of a large part of the Western Cape. Granite contains high levels of natural radionuclides, which results in high levels of natural background radiation in the surrounding area. The impacts of these high levels of radiation exposure on military personal are of concern. There are four military units located in this part of the West Coast, namely SAS Saldanha, 4 Special Forces Regiment, Langebaan Road Air Force Base and the Military Academy. Different sites in and around these military units were selected and soil samples were taken. Laboratory gamma ray measurements were done to determine the levels of natural radioactive nuclides in the soil samples. The radioactive nuclide concentrations were interpolated and then mapped with the help of geographic information systems (also known as geospatial information systems or GIS software. An evaluation of the annual dose rate of military personnel at the units on the West Coast was made and found to range between 0,017 mSv/y and 0,163 mSv/y. These values were mapped and compared to the average global annual dose rate of 0,070 mSv/y. This article reports on an investigation of these results and the overall exposure levels of personnel from the various military units on the West Coast of South Africa.

  18. Effects of dose, dose-rate and fraction on radiation-induced breast and lung cancers

    International Nuclear Information System (INIS)

    Recent results from a large Canadian epidemiologic cohort study of low-LET radiation and cancer will be described. This is a study of 64,172 tuberculosis patients first treated in Canada between 1930 and 1952, of whom many received substantial doses to breast and lung tissue from repeated chest fluoroscopies. The mortality of the cohort between 1950 and 1987 has been determined by computerized record linkage to the National Mortality Data Base. There is a strong positive association between radiation and breast cancer risk among the females in the cohort, but in contrast very little evidence of any increased risk in lung cancer. The results of this and other studies suggest that the effect of dose-rate and/or fractionation on cancer risk may will differ depending upon the particular cancer being considered. (author)

  19. Pre operational background radiation monitoring around Kudankulam Nuclear Power Project site - a decade long experience

    International Nuclear Information System (INIS)

    Pre-operational environmental background radiation monitoring around nuclear power plants is very important to understand baseline values existing in the site and also to identify any hot spots of naturally occurring high background radiation areas and their sources. These baseline measurements will act as a benchmark for future comparison after the reactors go into operation. The radiation measurements are continued during the operational phase of the plant and the results are compared to see whether there is any impact of the operation of the plant on the environment. A comprehensive background radiation monitoring plan has been in vogue at site from 2004 to meet this objective. This paper describes the different monitoring strategies adopted around Kudankulam Nuclear Power Project site and throws light on the pre operational background radiation levels in the environment

  20. Self-amplifying Hawking radiation and its background: a numerical study

    CERN Document Server

    Steinhauer, Jeff

    2016-01-01

    We numerically study an analogue black hole with two horizons with similar parameters to a recent experiment. We find that the Hawking radiation exists on a background which contains a density oscillation, a zero-frequency ripple. The Hawking radiation evolves from spontaneous to self-amplifying, while the background ripple grows steadily with no qualitative change. It is seen that the self-amplifying Hawking radiation has a non-zero frequency. The background ripple appears even before the inner horizon is created, in contrast to predictions. This work is in agreement with the recent observation of self-amplifying Hawking radiation, and explains some of the features seen. In contrast to recent works, our study differentiates between the Hawking radiation observed, and the evolution of the background.

  1. TL dating: low background gamma spectrometry as a tool for the determination of the annual dose

    International Nuclear Information System (INIS)

    The analysis of the natural radioactivity of archaeological artefacts for thermoluminescence (TL) dating is now realized in the CRIAA TL laboratory (Bordeaux) by low background gamma spectrometry. An original calibration procedure permits the non-destructive measurement of natural radioelement contents (K, U and Th) and the control of the equilibrium state of the U series (loss of 222Rn, ratio of activities 238U/226Ra). An intercomparison of analytical methods has shown the excellent potentialities of gamma spectrometry. The low detection limits and the easy implementation make this method particularly suitable for determining the annual dose for TL dating. (author)

  2. The influence of high doses of radiation in citrine stones

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M. I. [Universidade Nove de Julho - UNINOVE, Rua Vergueiro 235/249, 01504-001 Sao Paulo (Brazil); Caldas, L. V. E., E-mail: miteixeira@ipen.br [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The possibility of using samples of Brazilian stones as quartz, amethyst, topaz, jasper, etc. for high-dose dosimetry has been studied in recent years at IPEN, using the techniques of optical absorption (Oa), thermoluminescent (Tl), optically stimulated luminescence (OSL) and resonance paramagnetic electron (EPR). In this work, the Tl properties of citrine samples were studied. They were exposed to different doses of gamma radiation ({sup 60}Co). The natural citrine stone was extracted from a mine in Minas Gerais state, Brazil; it is a tecto silicate ranked as one of three-dimensional structure, showing clear yellow to golden brown color. The natural citrine stone is classified as quartz (SiO{sub 2}), and it has a lower symmetry and more compact reticulum. The Tl emission curve showed two peaks at 160 grades C and 220 grades C. To remove the Tl peak (160 grades C) of the sintered citrine pellet glow curves, different thermal treatments were tested during several time intervals. The Tl dose-response curve between 50 Gy and 100 kGy, the reproducibility of Tl response and the lower detection dose were obtained. The results show that citrine may be useful as high-dose detectors. (Author)

  3. How does radiative feedback from a UV background impact reionization?

    CERN Document Server

    Sobacchi, Emanuele

    2013-01-01

    An ionizing UV background (UVB) inhibits gas accretion and photo-evaporates gas from the shallow potential wells of small, dwarf galaxies. During cosmological reionization, this effect can result in negative feedback: suppressing star-formation inside HII regions, thus impeding their continued growth. It is difficult to model this process, given the enormous range of scales involved. We tackle this problem using a tiered approach: combining parameterized results from single-halo collapse simulations with large-scale models of reionization. In the resulting reionization models, the ionizing emissivity of galaxies depends on the local values of the reionization redshift and the UVB intensity. We present a physically-motivated analytic expression for the average minimum mass of star-forming galaxies, which can be readily used in modeling galaxy formation. We find that UVB feedback: (i) delays the end stages of reionization by less than 0.5 in redshift; (ii) results in a more uniform distribution of HII regions, ...

  4. Low-dose radiation employed in diagnostic imaging causes genetic effects in cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Ponzinibbio, Maria V.; Peral-Garcia, Pilar; Seoane, Analia (Inst. de Genetica Veterinaria, Univ. Nacional de La Plata CONICET, La Plata (Argentina)), e-mail: aseoane@fcv.unlp.edu.ar; Crudeli, Cintia (Agencia Nacional de Promocion Cientifica y Tecnologica, La Plata (Argentina))

    2010-11-15

    Background: Exposure to environmental, diagnostic, and occupational sources of radiation frequently involves low doses. Although these doses have no immediately noticeable impact on human health there is great interest in their long-term biological effects. Purpose: To assess immediate and time-delayed DNA damage in two cell lines exposed to low doses of ionizing radiation by using the comet assay and micronucleus test, and to compare these two techniques in the analysis of low-dose induced genotoxicity. Material and Methods: CHO and MRC-5 cells were exposed to 50 milliSievert (mSv) of ionizing radiation and assayed immediately after irradiation and at 16 or 12 passages post-irradiation, respectively. Comet assay and micronucleus test were employed. Results: The comet assay values observed in 50 mSv-treated cells were significantly higher than in the control group for both sample times and cell lines (P < 0.001). Micronuclei frequencies were higher in treated cells than in the control group (P < 0.01, CHO cells passage 16; P < 0.05, MRC-5 cells immediately after exposure; P < 0.01 MRC-5 cells passage 12). Correlation analysis between the two techniques was statistically significant (correlation coefficient 0.82, P < 0.05 and correlation coefficient 0.86, P < 0.05 for CHO and MRC-5 cells, respectively). Cells scored at passages 12 or 16 showed more damage than those scored immediately after exposure in both cell lines (no statistically significant differences). Conclusion: Cytomolecular and cytogenetic damage was observed in cells exposed to very low doses of X-rays and their progeny. A single low dose of ionizing radiation was sufficient to induce such response, indicating that mammalian cells are exquisitely sensitive to it. Comet and micronucleus assays are sensitive enough to assess this damage, although the former seems to be more efficient

  5. Is the Linear No-Threshold Dose-Response Paradigm Still Necessary for the Assessment of Health Effects of Low Dose Radiation?

    Science.gov (United States)

    Seong, Ki Moon; Seo, Songwon; Lee, Dalnim; Kim, Min-Jeong; Lee, Seung-Sook; Park, Sunhoo; Jin, Young Woo

    2016-02-01

    Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation. PMID:26908982

  6. Personal radiation monitoring and assessment of doses received by radiation workers (1996)

    International Nuclear Information System (INIS)

    Since late 1986, all persons monitored by the Australian Radiation Laboratory have been registered on a data base which maintains records of the doses received by each individual wearer. At present, the Service regularly monitors approximately 30,000 persons, which is roughly 90 percent of those monitored in Australia, and maintains dose histories of over 75,000 people. The skin dose for occupationally exposed workers can be measured by using one of the five types of monitor issued by the Service: Thermoluminescent Dosemeter (TLD monitor), Finger TLD 3, Neutron Monitor, Special TLD and Environmental monitor. The technical description of the monitors is provided along with the method for calculating the radiation dose. 5 refs., 7 tabs., 5 figs

  7. Personal radiation monitoring and assessment of doses received by radiation workers (1996)

    Energy Technology Data Exchange (ETDEWEB)

    Morris, N.D.

    1996-12-01

    Since late 1986, all persons monitored by the Australian Radiation Laboratory have been registered on a data base which maintains records of the doses received by each individual wearer. At present, the Service regularly monitors approximately 30,000 persons, which is roughly 90 percent of those monitored in Australia, and maintains dose histories of over 75,000 people. The skin dose for occupationally exposed workers can be measured by using one of the five types of monitor issued by the Service: Thermoluminescent Dosemeter (TLD monitor), Finger TLD 3, Neutron Monitor, Special TLD and Environmental monitor. The technical description of the monitors is provided along with the method for calculating the radiation dose. 5 refs., 7 tabs., 5 figs.

  8. High background radiation areas of Ram sar in Iran: evaluation of DNA damage by alkaline single cell gel electrophoresis (SCE)

    Energy Technology Data Exchange (ETDEWEB)

    Masoomi, J.R. [Biophysics Department, College of Sciences, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Mohammadi, Sh. [Radiation Molecular Genetic Laboratory, National Radiation Protection Department (NRPD), Iranian Nuclear Regulatory Authority (INRA), P.O. Box 14155-4494, Tehran (Iran, Islamic Republic of); Amini, M. [Faculty of Pharmacy, Azad University of Tehran (Iran, Islamic Republic of); Ghiassi-Nejad, M. [Biophysics Department, College of Sciences, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of)]. E-mail: ghiassi@mailcity.com

    2006-07-01

    The hot springs in special areas in Ram sar, a northern coastal town in Iran, contain {sup 226}Ra and {sup 222}Rn. The natural radiation effects, radiosensitivity or adaptive responses, on the inhabitants of high natural radiation in Ram sar were studied. The single cell gel electrophoresis was used to monitor DNA damages. Three groups of volunteers were selected, one from high natural background radiation areas as the case group and two from normal background radiation areas as controls (control 1 and control 2). The latter one had the similar living situation to case group while the other (control 2) had different living situation from the other groups. Peripheral blood mononuclear cells (PMNCs) were separated and irradiated by {sup 6}Co source at five different gamma doses. It was found that the spontaneous level of DNA damage and the induced DNA damage in all challenging doses in case group was considerably higher than control groups (p < 0.05). On the other hand, the repair rate in those volunteers, who received less than 10.2 mSv/y was significantly more than the control groups. In the contrary, individuals who live in homes with more than 10.2 mSv/y had incomplete repair. Additionally the plasma and urinary levels of vitamin C were measured spectrophotometrically. Although the concentration of vitamin C of plasma was equal in case and control 1 groups, the urinary level of vitamin C was found to be lower in the case group.

  9. Modeling Background Radiation in our Environment Using Geochemical Data

    Energy Technology Data Exchange (ETDEWEB)

    Malchow, Russell L.; Marsac, Kara [University of Nevada, Las Vegas; Burnley, Pamela [University of Nevada, Las Vegas; Hausrath, Elisabeth [Uniiversity of Nevada, Las Vegas; Haber, Daniel [University of Nevada, Las Vegas; Adcock, Christopher [University of Nevada, Las Vegas

    2015-02-01

    Radiation occurs naturally in bedrock and soil. Gamma rays are released from the decay of the radioactive isotopes K, U, and Th. Gamma rays observed at the surface come from the first 30 cm of rock and soil. The energy of gamma rays is specific to each isotope, allowing identification. For this research, data was collected from national databases, private companies, scientific literature, and field work. Data points were then evaluated for self-consistency. A model was created by converting concentrations of U, K, and Th for each rock and soil unit into a ground exposure rate using the following equation: D=1.32 K+ 0.548 U+ 0.272 Th. The first objective of this research was to compare the original Aerial Measurement System gamma ray survey to results produced by the model. The second objective was to improve the method and learn the constraints of the model. Future work will include sample data analysis from field work with a goal of improving the geochemical model.

  10. Small Bowel Dose Tolerance for Stereotactic Body Radiation Therapy.

    Science.gov (United States)

    LaCouture, Tamara A; Xue, Jinyu; Subedi, Gopal; Xu, Qianyi; Lee, Justin T; Kubicek, Gregory; Asbell, Sucha O

    2016-04-01

    Inconsistencies permeate the literature regarding small bowel dose tolerance limits for stereotactic body radiation therapy (SBRT) treatments. In this review, we organized these diverse published limits with MD Anderson at Cooper data into a unified framework, constructing the dose-volume histogram (DVH) Risk Map, demonstrating low-risk and high-risk SBRT dose tolerance limits for small bowel. Statistical models of clinical data from 2 institutions were used to assess the safety spectrum of doses used in the exposure of the gastrointestinal tract in SBRT; 30% of the analyzed cases had vascular endothelial growth factor inhibitors (VEGFI) or other biological agents within 2 years before or after SBRT. For every dose tolerance limit in the DVH Risk Map, the probit dose-response model was used to estimate the risk level from our clinical data. Using the current literature, 21Gy to 5cc of small bowel in 3 fractions has low toxicity and is reasonably safe, with 6.5% estimated risk of grade 3 or higher complications, per Common Terminology Criteria for Adverse Events version 4.0. In the same fractionation for the same volume, if lower risk is required, 16.2Gy has an estimated risk of only 2.5%. Other volumes and fractionations are also reviewed; for all analyzed high-risk small bowel limits, the risk is 8.2% or less, and the low-risk limits have 4% or lower estimated risk. The results support current clinical practice, with some possibility for dose escalation. PMID:27000513

  11. Improvements in extremity dose assessment in ionizing radiation medical applications

    International Nuclear Information System (INIS)

    Full text: Whole-body personal dosimetry is well established for the individual monitoring of radiation workers. Legal dosimetry is usually based on TL or film passive dosimeters worn on the trunk and evaluated by an authorised dosimetric service. However, although extremity and skin dosimetry is required by law for any practice where extremities or skin are the critical organs, the development of extremity dosemetry has not been as well established. Only a few European dosimetry services offer this service. Moreover, there is hardly any recommendation on the most suitable place for wearing this type of dosemeter. The present paper aims at testing the INTE-UPC ring dosemeter based on MCPNs and TLD-100 detectors on some users from the field of medicine, namely manual brachytherapy operators, nuclear medicine technologists from a radiopharmaceutical unit, personnel at a cyclotron facility with the corresponding FDG synthesis cells, radiographers and surgeons participating in interventional radiology. The staff were chosen due to the fact that they had a significantly high risk of exposure to their hands. According to previous results, MCPNs TL thin material is used in the radiology measurements, whereas TLD100 is preferred for the other applications. Prior to use, the dosemeters were tested for waterproof and cold sterilisation sensitivity. Preliminary results confirm the need to implement extremity dosimetry in the above- mentioned jobs, where finger dose can be of the order of 40 times the whole body dose and 3 times the wrist dose. Selection of an appropriate dosemeter can mean changes in the classification of the worker as category A or B. The study shows good correlation between workload and integrated dose, and small differences between experienced workers' dose. As a conclusion, some guidelines for radiation protection optimization are presented. (author)

  12. The assessment of the natural radiation dose committed to the Hong Kong people

    International Nuclear Information System (INIS)

    The natural radionuclide (238U, 226Ra, 232Th and 40K) contents of soil samples at various locations in Hong Kong, building materials commonly used in Hong Kong and construction materials for roads have been determined by low background gamma-ray spectroscopy using an n-type high purity germanium detector. From the measured radionuclide contents, estimations have been made of the absorbed gamma dose rate in air and the indoor radon concentration in Hong Kong. Both are in good agreement with in-situ measurements. Finally, calculations have been made of the annual individual effective dose equivalent contributed by all kinds of natural background radiations. The total value is 3.2 mSv which is about 60% higher than the global average. Of this total value, 80% comes from the radiation from building materials. The present work suggests that building materials are the primary source of natural background radiation in Hong Kong. Therefore, more extensive studies and perhaps limitation of the radionuclide concentration of building materials in the near future seems necessary. (author)

  13. The Cosmic Background Radiation circa ν2K

    Science.gov (United States)

    Bond, J. Richard; Pogosyan, Dmitry; Prunet, Simon

    We describe the implications of cosmic microwave background (CMB) observations and galaxy and cluster surveys of large scale structure (LSS) for theories of cosmic structure formation, especially emphasizing the recent Boomerang and Maxima CMB balloon experiments. The inflation-based cosmic structure formation paradigm we have been operating with for two decades has never been in better shape. Here we primarily focus on a simplified inflation parameter set, {ωb, ωcdm, Ωtot, ΩΛ, ns, τC, σ8}. Combining all of the current CMB+LSS data points to the remarkable conclusion that the local Hubble patch we can access has little mean curvature (Ωtot = 1.08 +/- 0.06) and the initial fluctuations were nearly scale invariant (ns = 1.03 +/- 0.08), both predictions of (non-baroque) inflation theory. The baryon density is found to be slightly larger than that preferred by independent Big Bang Nucleosynthesis estimates (ωb --- Ωbh2 = 0.030 +/- 0.005 cf. 0.019 +/- 0.002). The CDM density is in the expected range (ωcdm = 0.17+/-0.02). Even stranger is the CMB+LSS evidence that the density of the universe is dominated by unclustered energy akin to the cosmological constant (ΩΛ = 0.66 +/- 0.06), at the same level as that inferred from high redshift supernova observations. We also sketch the CMB+LSS implications for massive neutrinos.

  14. The Cosmic Background Radiation circa nu2K

    CERN Document Server

    Bond, J R; Prunet, S; Ade, P; Balbi, A; Bock, J J; Borrill, J; Boscaleri, A; Coble, K; Crill, B P; De Bernardis, P; Farese, P; Ferreira, P; Ganga, K; Giacometti, M; Hanany, S; Hivon, E; Hristov, V V; Iacoangeli, A; Jaffe, A; Lange, A; Lee, A; Martinis, L; Masi, S; Mauskopf, P D; Melchiorri, A; Montroy, T; Netterfield, C B; Oh, S; Pascale, E; Piacentini, F; Rabii, B; Rao, S; Richards, P; Romeo, G; Ruhl, J E; Scaramuzzi, F; Sforza, D M; Smoot, G F; Stompor, R; Winant, C; Wu, P

    2000-01-01

    We describe the implications of cosmic microwave background (CMB) observations and galaxy and cluster surveys of large scale structure (LSS) for theories of cosmic structure formation, especially emphasizing the recent Boomerang and Maxima CMB balloon experiments. The inflation-based cosmic structure formation paradigm we have been operating with for two decades has never been in better shape. Here we primarily focus on a simplified inflation parameter set, {omega_b,omega_{cdm},Omega_{tot}, Omega_\\Lambda,n_s,\\tau_C, \\sigma_8}. Combining all of the current CMB+LSS data points to the remarkable conclusion that the local Hubble patch we can access has little mean curvature (Omega_{tot}=1.08\\pm 0.06) and the initial fluctuations were nearly scale invariant (n_s=1.03\\pm 0.08), both predictions of (non-baroque) inflation theory. The baryon density is found to be slightly larger than that preferred by independent Big Bang Nucleosynthesis estimates (omega_b=0.030\\pm 0.005 cf. 0.019\\pm 0.002). The CDM density is in th...

  15. Radiation Risk Associated with Low Doses of Ionizing Radiation: Irrational Fear or Real Danger

    International Nuclear Information System (INIS)

    The established worldwide practice of protecting people from radiation based on the assessments of radiation risk received in the researches carried out earlier costs hundreds of billions of dollars a year to implement. In the opinion of the well-known experts, the maintenance of the existing radiation protection regulations or moreover acceptance of more tough regulations can influence the development of nuclear power engineering. The accepted practice of assessment of human health risk from radiation may also significantly affect our perception of threats of radiation terrorism. In this work, the critical analysis of publications on the assessment of the effects of small doses of radiation on human health is carried out. In our analysis, we especially emphasize the data on cancer mortality among survivors of the atomic bombing of Hiroshima and Nagasaki who received instantaneous radiation doses of less than 200 mSv including the data on leukemia and solid cancer, as well as epidemiological studies in the regions of India and China with high level of natural radiation. Since the investigations of radiation risk is a base for formulating modern radiation protection regulations, their reliability and validity are of great importance. As follows from the analysis, the subsequent, during three decades, toughening of radiation protection regulations has already led to exceedingly prohibitive standards and impractical recommendations the science-based validity of which can cause serious doubts. Now, a number of world-wide known scientists and authoritative international organizations call for revision of these standards and of the radiation safety concept itself. (author)

  16. The relationships between radiation doses and their effects

    International Nuclear Information System (INIS)

    Dose-effect relationships have been developed both for the biological effects studied by Radiobiology and the long-term pathological effects (malignant diseases) studied by Radiation Protection. The former approach chiefly considers the primary biological injuries at the cellular level, and the relationship between the dependent variable characteristic of the effect and the dose -an independent variable- has an explanatory meaning. The parameters associated to the independent variable have a biophysical signification and fit into a model of the action of ionizing radiations. In the latter approach, the relationship is pragmatic and the previous parameters are just the results of a curve-fitting procedure realized on experimental or human data. The biophysical models have led to a general formulation associating a linear term to a quadratic term both of them weighted by an exponential term describing cellular killing at the highest doses. To a certain extent the curves obtained for leukemias, bronchopulmonary and breast cancers prove the validity of the pragmatic model

  17. Risk of breast cancer following low-dose radiation exposure

    International Nuclear Information System (INIS)

    Risk of breast cancer following radiation exposure was studied, based on surveys of tuberculosis patients who had multiple fluoroscopic examinations of the chest, mastitis patients given radiotherapy, and atomic bomb survivors. Analysis suggests that the risk is greatest for persons exposed as adolescents, although exposure at all ages carries some risk. The dose-response relationship was consistent with linearity in all studies. Direct evidence of radiation risk at doses under 0.5 Gy (50 rad) is apparent among A-bomb survivors. Fractionation does not appear to diminish risk, nor does time since exposure (even after 45 years of observation). The interval between exposure and the clinical appearance of radiogenic breast cancer may be mediated by hormonal or other age-related factors but is unrelated to dose. Age-specific absolute risk estimtes for all studies are remarkably similar. The best estimate of risk among American women exposed after age 20 is 6.6 excess cancers/104 WY-Gy

  18. [Effect of chronic exposure to low doses of ionized radiation on embryonal development of the Japanese quail].

    Science.gov (United States)

    Gur'eva, T S; Dadasheva, O A; Tsetlin, V V; Mednikova, E I; Lebedeva, Z N

    2007-01-01

    Experiments on Japanese quail embryogenesis on a background of chronic exposure to gamma- and neutron doses comparable with the doses of ionized radiation inside the orbital space stations Mir and ISS, and exploration vehicles gave evidence that permanent absorption of low gamma-doses (0,15 cgy/d) did not impact development of the Japanese quail embryos. On the contrary, the neutron dose of 200 microgy/d imparted by the neutron flux of 30 particles/cm2s was hazardous to embryos as it caused morphological disorders in 12% of embryos. PMID:18672515

  19. Th Cell Gene Expression and Function in Response to Low Dose and Acute Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Daila S. Gridley, PhD

    2012-03-30

    FINAL TECHNICAL REPORT Supported by the Low Dose Radiation Research Program, Office of Science U.S. Department of Energy Grant No. DE-FG02-07ER64345 Project ID: 0012965 Award Register#: ER64345 Project Manager: Noelle F. Metting, Sc.D. Phone: 301-903-8309 Division SC-23.2 noelle.metting@science.doe.gov Submitted March 2012 To: https://www.osti.gov/elink/241.3.jsp Title: Th Cell Gene Expression and Function in Response to Low Dose and Acute Radiation PI: Daila S. Gridley, Ph.D. Human low dose radiation data have been derived primarily from studies of space and airline flight personnel, nuclear plant workers and others exposed occupationally, as well as victims in the vicinity of atomic bomb explosions. The findings remain inconclusive due to population inconsistencies and complex interactions among total dose, dose rate, radiation quality and age at exposure. Thus, safe limits for low dose occupational irradiation are currently based on data obtained with doses far exceeding the levels expected for the general population and health risks have been largely extrapolated using the linear-nonthreshold dose-response model. The overall working hypothesis of the present study is that priming with low dose, low-linear energy transfer (LET) radiation can ameliorate the response to acute high-dose radiation exposure. We also propose that the efficacy of low-dose induced protection will be dependent upon the form and regimen of the high-dose exposure: photons versus protons versus simulated solar particle event protons (sSPE). The emphasis has been on gene expression and function of CD4+ T helper (Th) lymphocytes harvested from spleens of whole-body irradiated C57BL/6 mice, a strain that provides the genetic background for many genetically engineered strains. Evaluations of the responses of other selected cells, tissues such as skin, and organs such as lung, liver and brain were also initiated (partially funded by other sources). The long-term goal is to provide information

  20. Radiation signature on exposed cells: Relevance in dose estimation

    Institute of Scientific and Technical Information of China (English)

    Venkatachalam; Perumal; Tamizh; Selvan; Gnana; Sekaran; Venkateswarlu; Raavi; Safa; Abdul; Syed; Basheerudeen; Karthik; Kanagaraj; Amith; Roy; Chowdhury; Solomon; FD; Paul

    2015-01-01

    The radiation is considered as a double edged sword, as its beneficial and detrimental effects have been demonstrated. The potential benefits are being exploited to its maximum by adopting safe handling of radionuclide stipulated by the regulatory agencies. While the occupational workers are monitored by personnel monitoring devices, for general publics, it is not a regular practice. However, it can be achieved by using biomarkers with a potential for the radiation triage and medical management. An ideal biomarker to adopt in those situations should be rapid, specific, sensitive, reproducible, and able to categorize the nature of exposure and could provide a reliable dose estimation irrespective of the time of the exposures. Since cytogenetic markers shown to have many advantages relatively than other markers, the origins of various chromosomal abnormalities induced by ionizing radiations along with dose-response curves generated in the laboratory are presented. Current status of the gold standard dicentric chromosome assay, micronucleus assay, translocation measurement by fluorescence insitu hybridization and an emerging protein marker the g-H2 AX assay are discussed with our laboratory data. With the wide choice of methods, an appropriate assay can be employed based on the net.

  1. Radiation signature on exposed cells: Relevance in dose estimation.

    Science.gov (United States)

    Perumal, Venkatachalam; Gnana Sekaran, Tamizh Selvan; Raavi, Venkateswarlu; Basheerudeen, Safa Abdul Syed; Kanagaraj, Karthik; Chowdhury, Amith Roy; Paul, Solomon Fd

    2015-09-28

    The radiation is considered as a double edged sword, as its beneficial and detrimental effects have been demonstrated. The potential benefits are being exploited to its maximum by adopting safe handling of radionuclide stipulated by the regulatory agencies. While the occupational workers are monitored by personnel monitoring devices, for general publics, it is not a regular practice. However, it can be achieved by using biomarkers with a potential for the radiation triage and medical management. An ideal biomarker to adopt in those situations should be rapid, specific, sensitive, reproducible, and able to categorize the nature of exposure and could provide a reliable dose estimation irrespective of the time of the exposures. Since cytogenetic markers shown to have many advantages relatively than other markers, the origins of various chromosomal abnormalities induced by ionizing radiations along with dose-response curves generated in the laboratory are presented. Current status of the gold standard dicentric chromosome assay, micronucleus assay, translocation measurement by fluorescence in-situ hybridization and an emerging protein marker the γ-H2AX assay are discussed with our laboratory data. With the wide choice of methods, an appropriate assay can be employed based on the net. PMID:26435777

  2. Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Linda X., E-mail: lhong0812@gmail.com [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Shankar, Viswanathan [Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (United States); Shen, Jin [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Kuo, Hsiang-Chi [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Mynampati, Dinesh [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Yaparpalvi, Ravindra [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Goddard, Lee [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Basavatia, Amar; Fox, Jana; Garg, Madhur; Kalnicki, Shalom; Tomé, Wolfgang A. [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States)

    2015-10-01

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R{sub 50%}); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D{sub 2cm}) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ{sup 2} test was used to examine the difference in parameters between groups. The PTV V{sub 100%} {sub PD} ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V{sub 90%} {sub PD} ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D{sub 2cm}, 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives.

  3. Ionizing radiation population doses at Sao Paulo city, Brazil: open-pit gamma dose measurement

    International Nuclear Information System (INIS)

    The effects of ionizing radiation to the human beings are well known for high and intermediate doses. As far as low level) radiation doses are concerned, there is no consensus. In order to get a better understanding of such effects it is necessary to assess the low doses with better accuracy. In this work, it was made an estimate of the annual ambient dose equivalent (H*(10)) to which the people are exposed in the city of Sao Paulo. Until now there are no data about it available in the literature. For the purpose of this evaluation, a map with various routes covering the largest and more representative area of the city was designed. The choice of points for data collection was made taking into account mainly the occupancy of the region. A portable gamma spectrometry system was used. It furnishes the rate of H*(10) and the measured gamma spectrum (in the range from 50 to 1670 keV) in the place of interest. The measurements were performed in a short time interval, since the gamma radiation arrives from a great extent of soil. Each measurement was done 1 m above the soil during 300 s. The rates of H*(10) varied from 33.1 to 152.3 nSv.h-1, net values, obtained after subtraction of the cosmic rays contribution. The standard deviation was 22 n Sv.h-1 for an average for the city of Sao Paulo of 96.1(24) nSv.h-1. In addition, average values of H*(10) rates for the city Health Divisions were calculated. Those values are not statistically equivalent and the whole set of data could not be treated as one, as the statistical Student test indicated a non homogeneity of the group of data. Hence it is necessary the accomplishment of a more detailed survey in order to verify the origin of the discrepancy. The mean value of H*(10) rate obtained for the city of Sao Paulo as converted to effective dose. in order to be compared with other places results It could be noticed that the annual average of effective dose for the city of Sao Paulo, 0.522(13) mSv, is superior to the world

  4. The cosmic background radiation circa {nu}2K

    Energy Technology Data Exchange (ETDEWEB)

    Bond, J. Richard; Pogosyan, Dmitry; Prunet, Simon

    2000-01-01

    We describe the implications of cosmic microwave background (CMB) observations and galaxy and cluster surveys of large scale structure (LSS) for theories of cosmic structure formation, especially emphasizing the recent Boomerang and Maxima CMB balloon experiments. The inflation-based cosmic structure formation paradigm we have been operating with for two decades has never been in better shape. Here we primarily focus on a simplified inflation parameter set, {l_brace}{omega}{sub b}, {omega}{sub cdm}, {omega}{sub tot}, {omega}{sub {lambda}}, n{sub s}, {tau}{sub C}, {sigma}{sub 8}{r_brace}. Combining all of the current CMB+LSS data points to the remarkable conclusion that the local Hubble patch we can access has little mean curvature ({omega}{sub tot} = 1.08 {+-} 0.06) and the initial fluctuations were nearly scale invariant (n{sub s} 1.03 {+-} 0.08), both predictions of (non-baroque) inflation theory. The baryon density is found to be slightly larger than that preferred by independent Big Bang Nucleosynthesis estimates ({omega}{sub b}-{omega}{sub b}h{sup 2} 0.030 {+-} 0.005 cf. 0.019 {+-} 0.002). The CDM density is in the expected range ({omega}{sub cdm} 0.17{+-}0.02). Even stranger is the CMB+LSS evidence that the density of the universe is dominated by unclustered energy akin to the cosmological constant ({omega}{sub {lambda}} = 0.66 {+-} 0.06), at the same level as that inferred from high redshift supernova observations. We also sketch the CMB+LSS implications for massive neutrinos.

  5. Health Risks From Low Doses and Low Dose-Rates of Ionizing Radiation. Session 5: Future of Radiation Protection Regulations.

    Science.gov (United States)

    Cool, Donald A

    2016-03-01

    The system of radiological protection is a prospective approach to protection of individuals in all exposure situations. It must be applied equitably across all age groups and all populations. This is a very different circumstance from dose assessment for a particular individual where the unique characteristics of the individual and the exposure can be taken into account. Notwithstanding the ongoing discussions on the possible shape of the dose response at low doses and dose rates, the prospective system of protection has therefore historically used a linear assumption as a pragmatic, prudent and protective approach. These radiation protection criteria are not intended to be a demarcation between "safe" and "unsafe" and are the product of a risk-informed judgement that includes inputs from science, ethics, and experience. There are significant implications for different dose response relationships. A linear model allows for equal treatment of an exposure, irrespective of the previously accumulated exposure. In contrast, other models would predict different implications. Great care is therefore needed in separating the thinking around risk assessment from risk management, and prospective protection for all age groups and genders from retrospective assessment for a particular individual. In the United States, the prospective regulatory structure functions effectively because of assumptions that facilitate independent treatment of different types of exposures, and which provide pragmatic and prudent protection. While the a linear assumption may, in fact, not be consistent with the biological reality, the implications of a different regulatory model must be considered carefully. PMID:26808877

  6. Distribution of background radiation and radioactive materials in Aomori Prefecture

    International Nuclear Information System (INIS)

    The first commercial nuclear fuel reprocessing plant in Japan is now being constructed in Rokkasho Village, Aomori Prefecture and large amounts of Pu and U will be treated in the plant. Therefore, we made a plan for getting background levels of Pu, U and other related radionuclides in soil samples around the plant beginning with plowed fields, then rice fields, orchards, forests and un-cultivated fields, ie a different field type, year by year. This is the first report of results for plowed fields. The soil samples were collected at 13 plowed fields in Rokkasho and three control sites in Tohoku Town, Hachinohe City and Hirosaki City. Five core samples of 75 mmφ, down to approximately 1 m deep, were taken in each field in 2001. Three to five layers were distinguished by a visual inspection, and the same layers from each of the five cores were combined. When depth profiles of layers for some cores were different from those of others, those cores were separately treated. Concentrations of 137Cs and 210Pb in the sample were measured with γ-ray spectrometers using Ge detectors. Pu, U and Th in the soil samples were analyzed with a ICP-MS. Since fields under yam (Dioscorea babatus) cultivation are dug up to approximately 1 m deep at harvesting, depth profiles of fallout radionuclides were heavily disturbed for most fields in Rokkasho. The mean and standard deviation of inventory of Pu (239+240Pu) in three fields where have not cultivated yam in Rokkasho was 120 ± 50 Bq m-2. The mean inventory was similar to that in Hachinohe City. However, the inventory was approximately a half of that in Hirosaki City. The Pu concentrations very well correlated with 137Cs (r=0.97), and the ratio of Pu/137Cs was 0.037 ± 0.007, which is a typical value for global fallout. This showed that the movements of Pu and 137Cs in soil were similar in spite of heavy soil disturbance, and the ratio could be used for distinguishing the plant Pu from global fallout. Since the concentrations of

  7. Radiation dose and image quality for paediatric interventional cardiology

    Science.gov (United States)

    Vano, E.; Ubeda, C.; Leyton, F.; Miranda, P.

    2008-08-01

    Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 µGy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 µGy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.

  8. Radiation dose and image quality for paediatric interventional cardiology

    Energy Technology Data Exchange (ETDEWEB)

    Vano, E [Radiology Department, Medicine School, Complutense University and San Carlos University Hospital, 28040 Madrid (Spain); Ubeda, C [Clinical Sciences Department, Faculty of the Science of Health, Tarapaca University, 18 de Septiembre 2222, Arica (Chile); Leyton, F [Institute of Public Health of Chile, Marathon 1000, Nunoa, Santiago (Chile); Miranda, P [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Avenida Antonio Varas 360, Providencia, Santiago (Chile)], E-mail: eliseov@med.ucm.es

    2008-08-07

    Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 {mu}Gy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 {mu}Gy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.

  9. Mortality risk coefficients for radiation-induced cancer at high doses and dose-rates, and extrapolation to the low dose domain.

    Science.gov (United States)

    Liniecki, J

    1989-01-01

    Risk coefficients for life-long excessive mortality due to radiation-induced cancers are presented, as derived in 1988 by the U.N. Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), principally on the basis of follow-up from A-bomb survivors in Japan, over the period from 1950 through 1985. The data are based on the new, revised dosimetry (DS 86) in the two cities, and reflect the effects of high and intermediate doses of basically low LET radiation delivered instantaneously. The author presents arguments relevant to the extrapolation of the risk to the low dose (dose rate) domain, as outlined by UNSCEAR in its 1986, and the NCRP (USA) in its 1980, (no 64), reports. The arguments are based on models and dose-response relationships for radiation action, derived from data on cellular radiobiology, animal experiments on radiation-induced cancers and life shortening, as well as the available limited human epidemiological evidence. The available information points to the lower effectiveness of sparsely ionizing radiation at low doses and low dose-rates, as compared with that observed for high, acutely delivered doses. The possible range of the reduction values (DREF) is presented. For high LET radiations, the evidence is less extensive and sometimes contradictory; however, it does not point to a reduction of the effectiveness at low doses/dose-rates, relative to the high dose domain. Practical consequences of these facts are considered. PMID:2489419

  10. Improvement of quantification of somatic radiation risks at low doses

    International Nuclear Information System (INIS)

    In this research contract several selected topics of basic relevancy for assessment models of radiological consequences of hypothetical reactor accidents have been considered. The investigations focussed on the following areas: 1) Age dependent dose conversion factors for members of the public and their variability for radioisotopes of iodine, strontium, and caesium, - improvement of the accuracy of dose calculations for external gamma irradiation from cloud- and ground-shine; 2) analysis of data and models relevant for the assessment of exposure-time-effect relationships for lethal somatic late effects of lung and breast cancer and of leukemia; 3) analysis of various health status indices (e.g. ''loss of healthy life span'') with respect to their usefulness in addition to incidence, mortality, etc. for the evaluation of the magnitude of a health detriment due to a previous radiation exposure. (orig./HP)

  11. Radiation doses in angiography in the University Hospital of Caracas

    International Nuclear Information System (INIS)

    In the present work is evaluated, in angiography procedures carried out in the Radiology Department of the University Hospital of Caracas, the radiation dose received by the exposed professional when they carry out these explorations invasive and the followed norms of radiological protection during the exploration. The measurement was carried out on the exposed professional conformed by a medical interventionist, a medical assistant (resident), a nurse and a technical radiologist. Dosimeters TL was placed in the inter-orbital line at level of the crystalline lens, on thyroid, on the hands, thorax, breast, and on the gonads. The maximum values of dose (in mGy) that were measured: 1,84 at level of the crystalline lens; 1,24 on thyroid; 9,04 on the right hand; 65,04 on hand left; 0,07 on thorax; 0,07 on Breast; 0,07 for ovaries; and smaller than 0,04 for testicle. (author)

  12. Source term calculations for assessing radiation dose to equipment

    International Nuclear Information System (INIS)

    This study examines results of analyses performed with the Source Term Code Package to develop updated source terms using NUREG-0956 methods. The updated source terms are to be used to assess the adequacy of current regulatory source terms used as the basis for equipment qualification. Time-dependent locational distributions of radionuclides within a containment following a severe accident have been developed. The Surry reactor has been selected in this study as representative of PWR containment designs. Similarly, the Peach Bottom reactor has been used to examine radionuclide distributions in boiling water reactors. The time-dependent inventory of each key radionuclide is provided in terms of its activity in curies. The data are to be used by Sandia National Laboratories to perform shielding analyses to estimate radiation dose to equipment in each containment design. See NUREG/CR-5175, ''Beta and Gamma Dose Calculations for PWR and BWR Containments.'' 6 refs., 11 tabs

  13. Radiation dose optimization in CT planning of corrective scoliosis surgery. A phantom study.

    OpenAIRE

    Abul-Kasim, Kasim; Gunnarsson, Mikael; Maly, Pavel; Ohlin, Acke; Sundgren, Pia

    2008-01-01

    The aim of the study was to explore the possibility of obtaining a helical CT scan of a long segment of vertebral column, optimally reduce the radiation dose, compare the radiation dose of the low dose helical CT with that of some of the CT protocols used in clinical practice and finally assess the impact of such a dose reduction on the image quality. A chest phantom was examined with a 16-slice CT scanner. Six scans were performed with different radiation doses. The lowest radiation dose whi...

  14. Perspectives on radiation dose estimates for A-bomb survivors

    Energy Technology Data Exchange (ETDEWEB)

    Loewe, W.E.

    1986-12-01

    Four decades after the actual events, quantitative characterization of the radiation fields at Hiroshima and Nagasaki continues to be sought, with high accuracy a goal justified by the unique contribution to radiation protection standards that is represented by the medical records of exposed survivors. The most recent effort is distinguished by its reliance on computer modeling and concomitant detail, and by its decentralized direction, both internationally and internally to the US and Japan, with resultant ongoing peer review and wide scope of inquiry. A new system for individual dose estimation has been agreed upon, and its scientific basis has been elaborated in the literature as well as in a comprehensive treatise to be published in the Spring of 1987. In perspective, this new system appears to be an unusually successful achievement that offers the expectation of reliable estimates with the desired accuracy. Some aspects leading to this expectation, along with a caveat, are discussed here. 4 refs., 8 figs., 3 tabs.

  15. The spectrum of mutation produced by low dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Morley,Alexander,A; Turner, David,R

    2004-10-31

    Inherited mutations are the basis of evolution and acquired mutations in humans are important in ageing, cancer and possibly various forms of tissue degeneration. Mutations are responsible for many of the long-term effects of radiation. However, sensitive direct detection of mutations in humans has been difficult. The aims of the project were to develop methods for the sensitive enumeration of mutations in DNA, to measure mutation frequencies in a wide variety of tissue types and to quantify the mutational effect of direct oxidative damage produced by radiation, at both high and low doses. The project was successful in developing a sensitive method which could detect mutations directly in the genetic material, DNA at a sensitivity of 1 mutated molecule in 1000000000 unmutated molecules. However a number of methodological problems had to be overcome and lack of ongoing funding made it impossible to fulfill all of the aims of the project

  16. Radiation dose evaluation in patients submitted to conventional radiological examinations

    International Nuclear Information System (INIS)

    This work presents the results of the evaluation of radiation dose delivered to the patients undergoing conventional radiological procedures. Based in the realized measurement some indicators are settled to quantitative appraisal of the radiological protection conditions offered to the population. Data assessment was done in the county of Curitiba, in Parana State, Brazil, from 12/95 to 04/96, in ten rooms of three different institutions, under 101 patients, adults with 70 ± 10 kg, during real examinations of chest PA, chest LAT and abdomen AP. (author)

  17. Exposure to low dose ionising radiation: Molecular and clinical consequences.

    LENUS (Irish Health Repository)

    Martin, Lynn M

    2014-07-10

    This review article provides a comprehensive overview of the experimental data detailing the incidence, mechanism and significance of low dose hyper-radiosensitivity (HRS). Important discoveries gained from past and present studies are mapped and highlighted to illustrate the pathway to our current understanding of HRS and the impact of HRS on the cellular response to radiation in mammalian cells. Particular attention is paid to the balance of evidence suggesting a role for DNA repair processes in the response, evidence suggesting a role for the cell cycle checkpoint processes, and evidence investigating the clinical implications\\/relevance of the effect.

  18. Effects of low doses of ionizing radiation; Effets des faibles doses de rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R. [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

    2006-07-01

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

  19. Radiation Doses to Hanford Workers from Natural Potassium-40

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lynch, Timothy P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Weier, Dennis R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2009-02-01

    The chemical element potassium is an essential mineral in people and is subject to homeostatic regulation. Natural potassium comprises three isotopes, 39K, 40K, and 41K. Potassium-40 is radioactive, with a half life of 1.248 billion years. In most transitions, it emits a β particle with a maximum energy of 0.560 MeV, and sometimes a gamma photon of 1.461 MeV. Because it is ubiquitous, 40K produces radiation dose to all human beings. This report contains the results of new measurements of 40K in 248 adult females and 2,037 adult males performed at the Department of Energy Hanford Site in 2006 and 2007. Potassium concentrations diminish with age, are generally lower in women than in men, and decrease with body mass index (BMI). The average annual effective dose from 40K in the body is 0.149 mSv y-1 for men and 0.123 mSv y-1 women respectively. Averaged over both men and women, the average effective dose per year is 0.136 mSv y-1. Calculated effective doses range from 0.069 to 0.243 mSv y-1 for adult males, and 0.067 to 0.203 mSv y-1 for adult females, a roughly three-fold variation for each gender. The need for dosimetric phantoms with a greater variety of BMI values should be investigated. From our data, it cannot be determined whether the potassium concentration in muscle in people with large BMI values differs from that in people with small BMI values. Similarly, it would be important to know the potassium concentration in other soft tissues, since much of the radiation dose is due to beta radiation, in which the source and target tissues are the same. These uncertainties should be evaluated to determine their consequences for dosimetry.

  20. Effects at exposure to low doses of ionising radiation. Carcinogenic effect - validity of the linear no-threshold model

    International Nuclear Information System (INIS)

    The paper considers the validity of the linear no-threshold model (LNT) for estimating the risk related to low (below 200 mSv) and very low (below 10 mSv) doses. LNT was launched in the early 60s aiming mainly at data registering and radiation protection (RP) measures, since it allows the estimation of the risk just by summing all radiation exposures regardless of the dose and dose rates. In 1965 the International Commission on Radiological Protection (ICRP) stated its position: 'As the existence of a threshold dose is unknown it has been assumed that even the smallest doses involve a proportionately small risk of induction of malignancies. Also, because of the lack of knowledge of the nature of the dose-effect relationship in the induction of malignancies in man - particularly at the dose levels which are relevant in radiological protection - the Commission sees no practical alternative, for the purposes of radiological protection, to assuming non-linear relationship between dose and effect, and that doses act cumulatively. The Commission is aware that the assumptions of no-threshold and of complete ditivity of all doses, but is satisfied that they are unlikely to lead to the underestimation of risks'. In the end of the 70s the discovery of oncogenes was interpreted as a scientific basis of this hypothesis, since only one mutation can transform a proto-oncogene into an oncogene. Meanwhile, LNT validity was questioned by many radiobiologists. The doubts were related to the scientific basis of LNT especially as regards very low doses. This debate is of great importance because the major aim of radiation protection is to estimate the risk related to doses of the order of few mSv, and these are the doses which are received in most of the medical examinations and which are comparable to values from the natural radiation background

  1. Reduction of Radiation Dose Requirements of Foods by Additives

    International Nuclear Information System (INIS)

    Utilizing a recording photometer, a rapid turbidimetric method was worked out for the determination of nisin and tylosin activity. Those antibiotics affected by irradiation with X-rays in the range of 0 to 800 krad were also investigated. In a solution of pH 5.7 containing pea extract, the activity of the antibiotics decreased at a high rate when irradiated up to 200 krad, however, this rate slowed down with further radiation treatment. Tylosin lactate proved more radiation resistant than nisin. When treated with dosages between 400 and 800 krad the activity of nisin decreased by 73 to 87% and that of tylosin lactate by only 52 to 57%. During one-month storage at room temperature the residual activity of both the irradiated and untreated antibiotic solutions remained practically unchanged. The addition of antibiotics increased the preserving effect of X-rays. A 1:1 mixture of peas and a solution containing 4% sugar and 1.5% salt was heat treated for 15 minutes at 70°C. Samples taken from the liquid phase of this mixture were treated with various radiation-antibiotic combinations. When 100 ppm Nisaplin or 1 ppm tylosin lactate was added the radiation dose requirement was a quarter of that needed in the control samples to ensure microbiological stability. (author)

  2. Telomere Length in Human Adults and High Level Natural Background Radiation

    OpenAIRE

    Birajalaxmi Das; Divyalakshmi Saini; Seshadri, M

    2009-01-01

    BACKGROUND: Telomere length is considered as a biomarker of aging, stress, cancer. It has been associated with many chronic diseases such as hypertension and diabetes. Although, telomere shortening due to ionizing radiation has been reported in vitro, no in vivo data is available on natural background radiation and its effect on telomere length. METHODOLOGY/PRINCIPAL FINDINGS: The present investigation is an attempt to determine the telomere length among human adults residing in high level na...

  3. Stereotactic body radiation therapy for melanoma and renal cell carcinoma: impact of single fraction equivalent dose on local control

    OpenAIRE

    Robinson William; Lewis Karl; Flaig Thomas; Gonzalez Rene; Schefter Tracey E; Kavanagh Brian D; Stinauer Michelle A; Chidel Mark; Glode Michael; Raben David

    2011-01-01

    Abstract Background Melanoma and renal cell carcinoma (RCC) are traditionally considered less radioresponsive than other histologies. Whereas stereotactic body radiation therapy (SBRT) involves radiation dose intensification via escalation, we hypothesize SBRT might result in similar high local control rates as previously published on metastases of varying histologies. Methods The records of patients with metastatic melanoma (n = 17 patients, 28 lesions) or RCC (n = 13 patients, 25 lesions) t...

  4. Study of doses of radiation from about 1 m on the ground to underground measured by radio-isotope cone penetrometers

    International Nuclear Information System (INIS)

    When wet density ρt of the ground is measured by using Radio-Isotope cone penetration test (RI-CPT), natural doses of radiation (The background: It is called BG) are measured in the state that the radiation source is not installed. Next, doses of radiation in the state to install an artificial radiation source are measured. There was a good correlation between air dose rate E(μSv/h) and number of counts N (cps) (It is called the counting rate at the following) measured by BG measurement. Then, we compared the air dose rate converted by using the counting rate with the published date of the environmental radiation monitoring system. As a result, it was revealed that both showed a good correlation. It became clear that RI-CPT is effective as the technique to measure the influence of natural dose of radiation from the ground level to underground. (author)

  5. Radiation-induced bystander effects and adaptive responses--the Yin and Yang of low dose radiobiology?

    Energy Technology Data Exchange (ETDEWEB)

    Mothersill, Carmel [Medical Physics and Applied Radiation Sciences Unit, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)]. E-mail: mothers@mcmaster.ca; Seymour, Colin [Medical Physics and Applied Radiation Sciences Unit, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)]. E-mail: seymouc@mcmaster.ca

    2004-12-02

    Our current knowledge of the mechanisms underlying the induction of bystander effects by low doses of high or low LET ionizing radiation is reviewed. The question of what actually constitutes a protective effect is discussed in the context of adaptive (often referred to as hormetic or protective) responses. Finally the review considers critically, how bystander effects may be related to observed adaptive responses or other seemingly protective effects of low doses exposures. Bystander effects induce responses at the tissue level, which are similar to generalized stress responses. Most of the work involving low LET radiation exposure discussed in the existing literature measures a death response. Since many cell populations carry damaged cells without being exposed to radiation (so-called 'background damage'), it is possible that low doses exposures cause removal of cells carrying potentially problematic lesions, prior to exposure to radiation. This mechanism could lead to the production of 'U-shaped' or hormetic dose-response curves. The level of adverse, adaptive or apparently beneficial response will be related to the background damage carried by the original cell population, the level of organization at which damage or harm are scored and the precise definition of 'harm'. This model may be important when attempting to predict the consequences of mixed exposures involving low doses of radiation and other environmental stressors.

  6. Implications of radiation dose and exposed populations on radiation protection in the 21st century.

    Science.gov (United States)

    Boice, John D

    2014-02-01

    Radiation is in the public eye because of Fukushima, computed tomography examinations, airport screenings, and possible terrorist attacks. What if the Boston Marathon pressure cooker had also contained a radioactive source? Nuclear power may be on the resurgence. Because of the increasing uses of radiation, the increases in population exposures, and the increasing knowledge of radiation effects, constant vigilance is needed to keep up with the changing times. Psychosocial disorders associated with the inappropriate (but real) fear of radiation need to be recognized as radiation detriments. Radiation risk communication, radiation education, and communication must improve at all levels: to members of the public, to the media, to other scientists, and to radiation professionals. Stakeholders must continue to be involved in all radiation protection initiatives. Finally, we are at a crisis as the number of war babies (me) and baby boomers (you?) who are also radiation professionals continues its rapid decline, and there are few in the pipeline to fill the current and looming substantial need: "The old road is rapidly agin'" (Dylan). NCRP has begun the WARP initiative-Where Are the Radiation Professionals?-an attempt to rejuvenate the pipeline of future professionals before the trickle becomes tiny drops. A Workshop was held in July 2013 with government agencies, military, private sector, universities, White House representatives, and societies to develop a coordinated and national action plan. A "Manhattan Project" is needed to get us "Back to the Future" in terms of the funding levels that existed in years past that provided the necessary resources to train, engage, and retain (a.k.a., jobs) the radiation professionals needed for the nation. If we don't keep swimmin' (Disney's Nemo) we'll "sink like a stone" (Dylan).Introduction of Implications of Radiation Dose and Exposed Populations (Video 2:06, http://links.lww.com/HP/A25). PMID:24378509

  7. Spectrum of the cosmic background radiation: early and recent measurements from the White Mountain Research Station

    International Nuclear Information System (INIS)

    The White Mountain Research Station has provided a support facility at a high, dry, radio-quiet site for measurements that have established the blackbody character of the cosmic microwave background radiation. This finding has confirmed the interpretation of the radiation as a relic of the primeval fireball and helped to establish the hot Big Bang theory as the standard cosmological model

  8. Injury of the blood-testies barrier after low-dose-rate chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Young Hoon; Bae Min Ji; Lee, Chang Geun; Yang, Kwang Mo; Jur, Kyu; Kim, Jong Sun [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-04-15

    The systemic effect of radiation increases in proportionally with the dose and dose rate. Little is known concerning the relationships between harmful effects and accumulated dose, which is derived from continuous low-dose rate radiation exposure. Recent our studies show that low-dose-rate chronic radiation exposure (3.49 mGy/h) causes adverse effects in the testis at a dose of 2 Gy (6 mGy/h). However, the mechanism of the low-dose-rate 2 Gy irradiation induced testicular injury remains unclear. The present results indicate that low-dose rate chronic radiation might affect the BTB permeability, possibly by decreasing levels of ZO-1, Occludin-1, and NPC-2. Furthermore, our results suggest that there is a risk of male infertility through BTB impairment even with low-dose-rate radiation if exposure is continuous.

  9. AAPM/RSNA Physics Tutorial for Residents: Topics in CT. Radiation dose in CT.

    Science.gov (United States)

    McNitt-Gray, Michael F

    2002-01-01

    This article describes basic radiation dose concepts as well as those specifically developed to describe the radiation dose from computed tomography (CT). Basic concepts of radiation dose are reviewed, including exposure, absorbed dose, and effective dose. Radiation dose from CT demonstrates variations within the scan plane and along the z axis because of its unique geometry and usage. Several CT-specific dose descriptors have been developed: the Multiple Scan Average Dose descriptor, the Computed Tomography Dose Index (CTDI) and its variations (CTDI(100), CTDI(w), CTDI(vol)), and the dose-length product. Factors that affect radiation dose from CT include the beam energy, tube current-time product, pitch, collimation, patient size, and dose reduction options. Methods of reducing the radiation dose to a patient from CT include reducing the milliampere-seconds value, increasing the pitch, varying the milliampere-seconds value according to patient size, and reducing the beam energy. The effective dose from CT can be estimated by using Monte Carlo methods to simulate CT of a mathematical patient model, by estimating the energy imparted to the body region being scanned, or by using conversion factors for general anatomic regions. Issues related to radiation dose from CT are being addressed by the Society for Pediatric Radiology, the American Association of Physicists in Medicine, the American College of Radiology, and the Center for Devices and Radiological Health of the Food and Drug Administration.

  10. Chromosome aberration, cancer mortality and hormetic phenomena among inhabitants in areas of high background radiation in China

    Energy Technology Data Exchange (ETDEWEB)

    Deqing, Chen; Luxin, Wei (High Background Radiation Research Group, Beijing (China))

    1991-12-01

    The respective average annual doses are about 330 and 110 mR/yr, in the high background radiation areas (HBRA) in Yangjiang County and the control areas (CA) in Enping and Taishan Counties. Both the HBRA and CA are in Guangdong Province which borders the South China Sea. The frequencies of chromosome aberration in circulating lymphocytes were examined for persons residing in the HBRA and CA. Those in the HBRA had increased frequencies of detectable abnormalities in stable aberrations (translocations and inversions) and unstable aberrations (dicentrics and rings). Previous reports have shown that when samples of circulating lymphocytes taken from inhabitants were tested in vitro for mitotic responses to phytohemagglutinin (PHA) and for the degree of unscheduled DNA synthesis (UDS) induced by UV-irradiation, there were higher responsiveness and UDS rates for those in the HBRA than in the CA. In contrast, mortality from all cancers and those from leukemia, breast and lung cancers that are inducible by radiation was not higher in the HBRA. Although the differences in the cancer mortality rates for the HBRA and CA are not significant, the findings are compatible with the assumption that the lower mortality from cancer in the HBRA is the result of the hormetic effects of the three-fold higher dose rate of background radiation in that areas. This assumption requires further study. (author).

  11. COMPARISON OF NATURAL BACKGROUND DOSE RATES FOR RESIDENTS OF THE AMARGOSA VALLEY, NV, TO THOSE IN LEADVILLE, CO, AND THE STATES OF COLORADO AND NEVADA

    Energy Technology Data Exchange (ETDEWEB)

    D. Moeller and L. C. Sun

    2006-02-24

    In the latter half of 2005, the U.S. Environmental Protection Agency (USEPA) published a Proposed Rule (40 CFR Part 197) for establishing a dose rate standard for limiting radionuclide releases from the proposed Yucca Mountain high-level radioactive waste repository during the time period from 10{sup 4} to 10{sup 6} years after closure. The proposed standard was based on the difference in the estimated total dose rate from natural background in the Amargosa Valley and the ''average annual background radiation'' for the State of Colorado. As defined by the USEPA, ''natural background radiation consists of external exposures from cosmic and terrestrial sources, and internal exposures from indoor exposures to naturally-occurring radon''. On the basis of its assessments, the USEPA estimated that the difference in the dose rate in the two identified areas was 3.5 mSv y{sup -1}. The purpose of this review was to provide an independent evaluation and review of this estimate. One of the first observations was that, because site-specific dose rate measurements for the Amargosa Valley ''were not available'', the dose rates for various sources of natural background in that area, used by the USEPA in its assessment, were based on modifications of the average values for the State of Nevada. A second observation was that the conversion factor applied in estimating the dose rates due to exposures to indoor radon and its decay products was a factor of 2 higher than the currently accepted value. Further review revealed that site-specific data for many natural background sources in the Amargosa Valley were available. One particularly important observation was that about 91% of the residents of that area live in mobile homes which, due to their construction and design, have indoor radon concentrations comparable to, or less than, those outdoors. For that reason, alone, the USEPA estimate of the average dose rate for

  12. X-γ Radiation Dose Survey for HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    SONGXiariying; LIXu; YANGJinwei

    2003-01-01

    X-γ radiation belong to the ionizing radiation. Ionizing radiation sinks to energy in organism but produce a disservice to the organism. Just as medicine, the disservice of the radiation towards Organism is decided by to accept radiation quantify, the radiation quantify was named dose. Radiation protection's basic missions is to want to result the dose to fix quantify. In this survey the dose at workplace and its surroundings environments of HL-2A device was measured and the assessment was given out.

  13. Assessment of medical occupational radiation doses in Costa Rica.

    Science.gov (United States)

    Mora, P; Acuña, M

    2011-09-01

    Participation of the University of Costa Rica (UCR) in activities in an IAEA Regional Project RLA/9/066 through training, equipment and expert missions, has enabled to setting up of a national personal monitoring laboratory. Since 2007, the UCR has been in charge of monitoring around 1800 medical radiation workers of the Social Security System. Individual external doses are measured with thermoluminescent dosemeter using a Harshaw 6600 Plus reader. The service has accreditation with ISO/IEC 17025:2005. Distribution of monitored medical personnel is as follows: 83 % in diagnostic radiology, 6 % in nuclear medicine and 6 % in radiotherapy. Preliminary values for the 75 percentile of annual H(p)(10) in mSv are: radiology 0.37; interventional radiology 0.41; radiotherapy 0.53 and nuclear medicine 1.55. The service provided by the UCR in a steady and reliable way can help to implement actions to limit the doses received by the medical workers and optimise their radiation protection programs. PMID:21856694

  14. Some trial for reducing radiation doses at radiographic measurement of the pelvis

    International Nuclear Information System (INIS)

    The radiation doses were measured by TLD on the skin surface at the x-ray measurement of the pelvis and the following results were obtained. The radiation doses determined by either Martius of Guthmann method. By applying additional aluminum filters thickening between 0.5 mm and 1.0 mm, 50% of the radiation doses were reduced at radiation voltage of between 105 kv and 110 kv. (author)

  15. Cosmic background radiation anisotropy in an open inflation, cold dark matter cosmogony

    Science.gov (United States)

    Kamionkowski, Marc; Ratra, Bharat; Spergel, David N.; Sugiyama, Naoshi

    1994-01-01

    We compute the cosmic background radiation anisotropy, produced by energy-density fluctuations generated during an early epoch of inflation, in an open cosmological model based on the cold dark matter scenario. At Omega(sub 0) is approximately 0.3-0.4, the Cosmic Background Explorer (COBE) normalized open model appears to be consistent with most observations.

  16. Time-dependent radiation dose estimations during interplanetary space flights

    Science.gov (United States)

    Dobynde, M. I.; Shprits, Y.; Drozdov, A.

    2015-12-01

    Time-dependent radiation dose estimations during interplanetary space flights 1,2Dobynde M.I., 2,3Drozdov A.Y., 2,4Shprits Y.Y.1Skolkovo institute of science and technology, Moscow, Russia 2University of California Los Angeles, Los Angeles, USA 3Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, Moscow, Russia4Massachusetts Institute of Technology, Cambridge, USASpace radiation is the main restriction for long-term interplanetary space missions. It induces degradation of external components and propagates inside providing damage to internal environment. Space radiation particles and induced secondary particle showers can lead to variety of damage to astronauts in short- and long- term perspective. Contribution of two main sources of space radiation- Sun and out-of-heliosphere space varies in time in opposite phase due to the solar activity state. Currently the only habituated mission is the international interplanetary station that flights on the low Earth orbit. Besides station shell astronauts are protected with the Earth magnetosphere- a natural shield that prevents significant damage for all humanity. Current progress in space exploration tends to lead humanity out of magnetosphere bounds. With the current study we make estimations of spacecraft parameters and astronauts damage for long-term interplanetary flights. Applying time dependent model of GCR spectra and data on SEP spectra we show the time dependence of the radiation in a human phantom inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease

  17. Radiation exposure dose on persons engaged in radiation-related industries in Korea

    International Nuclear Information System (INIS)

    This study investigated the status of radiation exposure doses since the establishment of the 'Regulations on Safety Management of Diagnostic Radiation Generation Device' in January 6, 1995. The level of radiation exposure in people engaged or having been engaged in radiation-related industries of inspection organizations, educational organization, military units, hospitals, public health centers, businesses, research organizations or clinics over a 5 year period from Jan. 1, 2000 to Dec. 31, 2004 was measured. The 149,205 measurement data of 57,136 workers registered in a measurement organization were analysed in this study. Frequency analysis, a Chi-square test, Chi-square trend test, and ANOVA was used for data analysis. Among 57,136 men were 40,870 (71.5%). 50.3% of them were radiologic technologists, otherwise medical doctors (22.7%), nurse (2.9%) and others (24.1%). The average of depth radiation and surface radiation during the 5-year period were found to decrease each year. Both the depth radiation and surface radiation exposure were significantly higher in males, in older age groups, in radiological technologists of occupation. The departments of nuclear medicine had the highest exposure of both depth and surface radiation of the divisions of labor. There were 1.98 and 2.57 per 1,000 person-year were exposed more than 20 mSv (limit recommended by International Commission on Radiological Protection) in depth and surface radiation consequently. The total exposure per worker was significantly decreased by year. But Careful awareness is needed for the workers who exposed over 20 mSv per year. In order to minimize exposure to radiation, each person engaged in a radiation-related industry must adhere to the individual safety management guidelines more thoroughly. In addition, systematic education and continuous guidance aimed at increasing the awareness of safety must be provided

  18. Acute radiation enteritis caused by dose-dependent radiation exposure in dogs: experimental research.

    Science.gov (United States)

    Xu, Wenda; Chen, Jiang; Xu, Liu; Li, Hongyu; Guo, Xiaozhong

    2014-12-01

    Accidental or intended radiation exposure in mass casualty settings presents a serious and on-going threat. The development of mitigating and treating agents requires appropriate animal models. Unfortunately, the majority of research on radiation enteritis in animals has lacked specific assessments and targeted therapy. Our study showed beagle dogs, treated by intensity-modulated radiation therapy (IMRT) for abdominal irradiation, were administered single X-ray doses of 8-30 Gy. The degree of intestinal tract injury for all of the animals after radiation exposure was evaluated with regard to clinical syndrome, endoscopic findings, histological features, and intestinal function. The range of single doses (8 Gy, 10-14 Gy, and 16-30 Gy) represented the degree of injury (mild, moderate, and severe, respectively). Acute radiation enteritis included clinical syndrome with fever, vomiting, diarrhea, hemafecia, and weight loss; typical endoscopic findings included edema, bleeding, mucosal abrasions, and ulcers; and intestinal biopsy results revealed mucosal necrosis, erosion, and loss, inflammatory cell infiltration, hemorrhage, and congestion. Changes in serum diamine oxides (DAOs) and d-xylose represented intestinal barrier function and absorption function, respectively, and correlated with the extent of damage (P enteritis, thus obtaining a relatively objective evaluation of intestinal tract injury based on clinical performance and laboratory examination. The method of assessment of the degree of intestinal tract injury after abdominal irradiation could be beneficial in the development of novel and effective therapeutic strategies for acute radiation enteritis.

  19. Study of the natural radiation background affected on the human body in some areas of Viet Nam

    International Nuclear Information System (INIS)

    The author had studied the natural radiation background in 68 districts belong 40 provinces and cities of Vietnam from 2002 to 2005. The estimated results clearly show that the average external irradiation dose levels and the average annual external radiation equivalent dose affected on the human body are 0.181± 0.0189 μSv/h and 1599 ± 171.8 μSv/year respectively, both are in normal limit; the highest levels are in Lai Chau district (Lai Chau province); the lowest levels are in Buon Ma Thuot city (DakLak province), Phuoc Son district (Quang Nam province), Tan An district (Long An province). The radon concentration in the human being and the average annual internal inhalation irradiation equivalent dose affected on the human beings are 26.9 ± 15.89 Bq/m3 and 392.88 ± 231.99 μSv/year respectively; the maximums are in Nha Trang city (Khanh Hoa province), Bac Binh district (Binh Phuoc province); the minimums are in Vung Tau city (Ba Ria- Vung Tau province), Tan An district (Long An province), Rach Gia district (Kien Giang province). The terrestrial radionuclide concentrations in the cereals, foodstuffs (rice, meat, vegetables), water, earth and the average annual internal irradiation equivalent dose are 829.2 ± 38.06 Bq/kg and 229.3 ± 67.70 μSv/year respectively; the highest levels are in Phong Tho district (Lai Chau province), Dien Bien city; the lowest levels are in Dong Xoai district (Binh Phuoc province), Tan An district (Long An province). The average total annual natural radiation background effective equivalent dose level affected on the human body is 2206.9 ± 529.30 μSv/year; the highest levels are in Lai Chau district (Lai Chau province); the lowest levels are in Tan An district (Long An province). The 14 maps of Natural Radiation Background in several localized regions belong 40 provinces and cities of Viet Nam had been set up. These results can reserve for serviceman and public health in the both wartime and peacetime. (author)

  20. Radiobiological analysis of region with higher radiation background. The effect of the background on the isomorphism of some enzymes

    International Nuclear Information System (INIS)

    An attempt is made to establish the the time when the prolong impact of slightly increased radiation background get over the compensator mechanisms of living systems. The object of investigation was the ecosystem of the Bay of Wromos (Black Sea, BG) and its surroundings where the flotation slack from an uranium mine was disposed. radioactivity. The following radiobiological picture of the site is obtained according to measurements performed: the alpha-activity of the beach sands is higher than one of the slack and is different in plants; the beta-activity is higher compared to controls in all samples investigated; the gamma spectra show high concentration of the members of U-238 and Th-232 series. The biological effect provoked by this heightened radiation background is studied by means of the isoenzymes as indicators of changes on molecular level. The isoenzyme spectra of lactate dehydrogenase and butyrol dehydrogenase is studied by vertical electrophoresis. The following species are tested: Tettigonia candata charp, Galliptumus italicus, Grillus campestris and Lumbicus terrestrial. An increase in activity and quantity of enzymes as well as changes of their isoenzyme spectra is observed. Calliptumus italicus could be used as a bio indicator of contamination, as it show better separation of the LDH and BDH-isoforms of LDH and BDH, and is more wide-spread. The increase in activity and quantity of some isoenzyme fractions in the conditions of this experiment is one of the possible mechanisms for increase in radioresistance of the living systems. 3 tabs., 2 figs., 8 refs

  1. OMINEX: Survey of internal dose monitoring programmes for radiation workers

    International Nuclear Information System (INIS)

    Monitoring of the workforce in the nuclear industries is carried out primarily in order to demonstrate compliance with European Union (EU) legislation and the Basic Safety Standards for the protection of the health of workers against the dangers arising from ionising radiation recommended by the International Atomic Energy Agency (IAEA). There is, however, no common strategy for internal dose monitoring programmes currently in use in the EU countries. Surveys have been carried out in which organisations were asked to provide information on the design of their internal dose monitoring programmes and on the costs of these programmes. Information was requested from both EU countries and Associated States. Databases for storage and reporting of all gained information were constructed, and results from the surveys have been compiled. This work was carried out within the EC 5th Framework Programme project, OMINEX, which aims to provide advice and guidance on designing and implementing internal dose monitoring programmes in the workplace in such a way that best use is made of available resources, while minimising costs. (author)

  2. Toward high-contrast breast CT at low radiation dose.

    Science.gov (United States)

    Keyriläinen, Jani; Fernández, Manuel; Karjalainen-Lindsberg, Marja-Liisa; Virkkunen, Pekka; Leidenius, Marjut; von Smitten, Karl; Sipilä, Petri; Fiedler, Stefan; Suhonen, Heikki; Suortti, Pekka; Bravin, Alberto

    2008-10-01

    This study was approved by the local research ethics committee, and patient informed consent was obtained. The purpose of this study was to demonstrate that high-spatial-resolution low-dose analyzer-based x-ray computed tomography (CT) can substantially improve the radiographic contrast of breast tissue in vitro when compared with that attained by using diagnostic mammography and CT. An excised human breast tumor was examined by using analyzer-based x-ray imaging with synchrotron radiation. The correspondence between analyzer-based x-ray images and diagnostic mammograms, CT images, and histopathologic findings was determined. Calcifications and fine details of soft tissue, which are at the contrast detection limit on diagnostic mammograms, are clearly visible on planar analyzer-based x-ray images. Analyzer-based x-ray CT yields high contrast from smoothly varying internal structures, such as tumorous mass lesions, corresponding to information on actual structures seen at histopathologic analysis. The mean glandular dose of 1.9 mGy in analyzer-based x-ray CT is approximately equivalent to the dose administered during single-view screening mammography. The improved visibility of mammographically indistinguishable lesions in vitro suggests that analyzer-based x-ray CT may be a valuable method in radiographic evaluation of the breast, thereby justifying further investigations. PMID:18796684

  3. Cardiovascular risks associated with low dose ionizing particle radiation.

    Directory of Open Access Journals (Sweden)

    Xinhua Yan

    Full Text Available Previous epidemiologic data demonstrate that cardiovascular (CV morbidity and mortality may occur decades after ionizing radiation exposure. With increased use of proton and carbon ion radiotherapy and concerns about space radiation exposures to astronauts on future long-duration exploration-type missions, the long-term effects and risks of low-dose charged particle irradiation on the CV system must be better appreciated. Here we report on the long-term effects of whole-body proton ((1H; 0.5 Gy, 1 GeV and iron ion ((56Fe; 0.15 Gy, 1GeV/nucleon irradiation with and without an acute myocardial ischemia (AMI event in mice. We show that cardiac function of proton-irradiated mice initially improves at 1 month but declines by 10 months post-irradiation. In AMI-induced mice, prior proton irradiation improved cardiac function restoration and enhanced cardiac remodeling. This was associated with increased pro-survival gene expression in cardiac tissues. In contrast, cardiac function was significantly declined in (56Fe ion-irradiated mice at 1 and 3 months but recovered at 10 months. In addition, (56Fe ion-irradiation led to poorer cardiac function and more adverse remodeling in AMI-induced mice, and was associated with decreased angiogenesis and pro-survival factors in cardiac tissues at any time point examined up to 10 months. This is the first study reporting CV effects following low dose proton and iron ion irradiation during normal aging and post-AMI. Understanding the biological effects of charged particle radiation qualities on the CV system is necessary both for the mitigation of space exploration CV risks and for understanding of long-term CV effects following charged particle radiotherapy.

  4. Radiolytic yield of ozone in air for low dose neutron and x-ray/gamma-ray radiation

    International Nuclear Information System (INIS)

    Radiation ionizes surrounding air and produces molecular species, and these localized effects may be used as a signature of, and for quantification of, radiation. Low-level ozone production measurements from radioactive sources have been performed in this work to understand radiation chemical yields at low doses. The University of New Mexico AGN-201 M reactor was used as a tunable radiation source. Ozone levels were compared between reactor-on and reactor-off conditions, and differences (0.61 to 0.73 ppb) well below background levels were measured. Simulations were performed to determine the dose rate distribution and average dose rate to the air sample within the reactor, giving 35 mGy of mixed photon and neutron dose. A radiation chemical yield for ozone of 6.5±0.8 molecules/100 eV was found by a variance weighted average of the data. The different contributions of photons and neutrons to radiolytic ozone production are discussed. - Highlights: • Localized ozone production in air may be an indicator of radioactive material. • Radiolytic ozone work is dominated by high radiation fields in the saturation regime. • For low level measurements we used a reactor as a mixed photon/neutron source. • Monte Carlo simulations were performed to understand the dose profile to air. • Different contributions to ozone production are discussed for neutrons and photons

  5. DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Behne, Patrick Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-08

    The modeling of the detectability of special nuclear material (SNM) at ports and border crossings requires accurate knowledge of the background radiation at those locations. Background radiation originates from two main sources, cosmic and terrestrial. Cosmic background is produced by high-energy galactic cosmic rays (GCR) entering the atmosphere inducing a cascade of particles that eventually impact the earth’s surface. The solar modulation potential represents one of the primary inputs to modeling cosmic background radiation. Usosokin et al. formally define solar modulation potential as “the mean energy loss [per unit charge] of a cosmic ray particle inside the heliosphere…” Modulation potential, a function of elevation, location, and time, shares an inverse relationship with cosmic background radiation. As a result, radiation detector thresholds require adjustment to account for differing background levels, caused partly by differing solar modulations. Failure to do so can result in higher rates of false positives and failed detection of SNM for low and high levels of solar modulation potential, respectively. This study focuses on solar modulation’s time dependence and seeks the best method to predict modulation for future dates using Python. To address the task of predicting future solar modulation, we utilize both non-linear least squares sinusoidal curve fitting and cubic spline interpolation. This material will be published in transactions of the ANS winter meeting of November, 2016.

  6. Radiation dose assessment of musa acuminata - triploid (AAA)

    International Nuclear Information System (INIS)

    Bananas are radioactive due to the presence of the radioisotope-40K. This imposes a possible health risk to the general public. This study intended to assess the annual equivalent dosages and the annual effective dosage committed by the body. This seeks to benefit the general public, students and researchers, and entrepreneurs. Using atomic absorption spectrophotometry, lakatan banana (Musa acuminata-triploid (AAA), the most purchased variety cultivated in Barangay Adlawon, Cebu City, Philippines, was found to contain 0.53 g of total potassium for every 100 g of its fresh fruit wherein 6.2 x 10-5 g of which is potassium-40. Based on its 40K content banana was calculated to have a radioactivity of 16 Bq/100 g. it was found out that the body is exposed to radiation dosages ranging from 2.8 x 10-3 rem annually by eating 100 g of lakatan bananas everyday. Conversely, it is equivalent to the annual effective dosage of 0.0043 rem; the amount at which the body of an individual is uniformly exposed. However, no or extremely minute health risk was determined by just eating bananas. In fact, to exceed the radiation dose limits set by the International Commission on Radiation Protection, an individual may eat 116 kg of lakatan bananas everyday for a year. Fertilizers may be the major source of the radioisotope - 40K and assimilated by the plants. (author)

  7. Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

    2007-02-07

    Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash.

  8. Technology Development for Radiation Dose Measurement and Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bong Hwan; Chang, S. Y.; Lee, T. Y. (and others)

    2007-06-15

    The correction factors essential for the operation of In-Vivo counting system were produced and implemented into a field operation for the improvement of accuracy in measurement of the radioactivity inside a human body. The BiDAS2007 code which calculate an internal dose was developed by upgrading the former code prepared in the previous stage of this project. The method of using the multibioassy data, the maximum likelihood function and the Bayesian statistics were established to an internal dose based on the measurement data of radioactivity, intakes and retention of radioactivity in a human body and it can improve the accuracy in estimation of the intakes of radioactivity and the committed effective dose equivalent. In order to solve the problem of low detection efficiency of the conventional Bonner Sphere (BS) to a high energy neutron, the extended BS's were manufactured and the technique for neutron field spectrometry was established. The fast neutron and gamma spectrometry system with a BC501A scintillation detector was also prepared. Several neutron fluence spectra at several nuclear facilities were measured and collected by using the extended BS. The spectrum weighted responses of some neutron monitoring instruments were also derived by using these spectra and the detector response functions. A high efficient TL material for the neutron personal dosimeter was developed. It solved the main problem of low thermal stability and high residual dose of the commercial TLDs and has the sensitivity to neutron and to gamma radiation with 40 and 10 times higher respectively than them.

  9. Coronary computed tomography angiography using ultra-low-dose contrast media: radiation dose and image quality.

    Science.gov (United States)

    Komatsu, Sei; Kamata, Teruaki; Imai, Atsuko; Ohara, Tomoki; Takewa, Mitsuhiko; Ohe, Ryoko; Miyaji, Kazuaki; Yoshida, Junichi; Kodama, Kazuhisa

    2013-08-01

    To analyze the invasiveness and image quality of coronary CT angiography (CCTA) with 80 kV. We enrolled 181 patients with low body weight and low calcium level. Of these, 154 patients were randomly assigned to 1 of 3 groups: 280 HU/80 kV (n = 51); 350 HU/80 kV (n = 51); or 350 HU/120 kV (n = 52). The amount of contrast media (CM) was decided with a CT number-controlling system. Twenty-seven patients were excluded because of an invalid time density curve by timing bolus. The predicted amount of CM, volume CT dose index, dose-length product, effective dose, image noise, and 5-point image quality were measured. The amounts of CM for the 80 kV/280 HU, 80 kV/350 HU, and 120 kV/350 HU groups were 10 ± 4 mL, 15 ± 7 mL, and 30 ± 6 mL, respectively. Although image noise was greater at 80 than 120 kV, there was no significant difference in image quality between 80 kV/350 HU and 120 kV/350 HU (p = 0.390). There was no significant difference in image quality between 80 kV/280 HU and 80 kV/350 HU (4.4 ± 0.7 vs. 4.7 ± 0.4, p = 0.056). The amount of CM and effective dose was lower for 80 kV CCTA than for 120 kV CCTA. CCTA at 80 kV/280 HU may decrease the amount of CM and radiation dose necessary while maintaining image quality.

  10. MOSFET assessment of radiation dose delivered to mice using the Small Animal Radiation Research Platform (SARRP).

    Science.gov (United States)

    Ngwa, Wilfred; Korideck, Houari; Chin, Lee M; Makrigiorgos, G Mike; Berbeco, Ross I

    2011-12-01

    The Small Animal Radiation Research Platform (SARRP) is a novel isocentric irradiation system that enables state-of-the-art image-guided radiotherapy research to be performed with animal models. This paper reports the results obtained from investigations assessing the radiation dose delivered by the SARRP to different anatomical target volumes in mice. Surgically implanted metal oxide semiconductor field effect transistors (MOSFET) dosimeters were employed for the dose assessment. The results reveal differences between the calculated and measured dose of -3.5 to 0.5%, -5.2 to -0.7%, -3.9 to 0.5%, -5.9 to 2.5%, -5.5 to 0.5%, and -4.3 to 0% for the left kidney, liver, pancreas, prostate, left lung, and brain, respectively. Overall, the findings show less than 6% difference between the delivered and calculated dose, without tissue heterogeneity corrections. These results provide a useful assessment of the need for tissue heterogeneity corrections in SARRP dose calculations for clinically relevant tumor model sites. PMID:21962005

  11. A study of radiation exposure dose in young dental patients

    International Nuclear Information System (INIS)

    In order to clarify the trend in dental radiography for young patients up to 18 years old and the accompanying radiation exposures, surveys were made at Fukuoka Dental College Hospital and thirty-five dental offices in Fukuoka city and Kitakyushu city. Each kind of radiography increased in average number with age and 16-18 group was given 4.60 times of radiography of one kind or another in the clinic of college hospital. In the dental offices, the number of radiography taken was about one-fourth that of the clinic of college hospital. Although exposure dose varies with exposure factors, distance and angle of exposure, in addition to time factor, were found to affect doses subtly. In the clinic of college hospital the average of estimated doses to organs per person per year were 105.4 mrad (25.2 mrad for 5-year-old children) in the salivary gland, 55.9 mrad (18.9 mrad for 5-year-old) in the thyroid gland, 52.1 mrad (15.0 mrad for 5-year-old) in the lens of the eye and 52.2 mrad (8.7 mrad for 5-year-old) in the sella turcica. In the dental offices, the same average of estimated doses to organs were 40.5 mrad (7.4 mrad for 5-year-old) in the salivary gland, 17.4 mrad (8.0 mrad for 5-year-old) in the thyroid gland, 12.2 mrad (6.1 mrad for 5-year-old) in the lens of eye and 13.1 mrad (1.3 mrad for 5-year-old) in the sella turcica. In all kinds of radiograpy, the estimated doses in genital glands were in μrad. In the dental offices, both the percentage of young patients to all patients and the radiographing rate were lower as compared with those in the clinic of college hospital. The estimated doses were also lower at one-half to one-fifth and those by age and by organ were found to be one-tenth or lower. (J.P.N.)

  12. PABLM: a computer program to calculate accumulated radiation doses from radionuclides in the environment

    International Nuclear Information System (INIS)

    A computer program, PABLM, was written to facilitate the calculation of internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. This report contains details of mathematical models used and calculational procedures required to run the computer program. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides in the environment after the releases have ended. Radioactive decay is considered during the release of radionuclides, after they are deposited on the plants or ground, and during holdup of food after harvest. The radiation dose models consider several exposure pathways. Doses may be calculated for either a maximum-exposed individual or for a population group. The doses calculated are accumulated doses from continuous chronic exposure. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and MPC's of each radionuclide. The radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption that the contaminated medium is large enough to be considered an infinite volume or plane relative to the range of the emitted radiations. The equations for calculations of the radiation dose from external exposure to shoreline sediments include a correction for the finite width of the contaminated beach

  13. Individual Dose Monitor of External Radiation Personnel in IMP (1996~2001)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    For evaluating the individual annual effective dose of eternal radiation personnel in IMP, we monitored individual dose of external radiation personnel every year. The monitoring results are shown in Table 1, from which it is known from 1998 to 2001, we monitored 1099 workers, the mean annual effective dose is 0.13 mSv.

  14. Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

    Science.gov (United States)

    Zhao, Qian; Sun, Yeqing; Wang, Wei

    2016-07-01

    Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

  15. ABOUT THE IMPROVEMENT OF HEALTHFUL EVALUATION OF RADIATION DOSE IN X-RAY ODONTOLOGY

    OpenAIRE

    A. A. Cherednikova; S. I. Ivanov; N. A. Akopova

    2010-01-01

    The article represents the data about individual effective radiation doses adult patients in x-ray odontology procedures in medical organisations of Ryazan region. On the ground of the results collected in radiation induced characteristics of the x-ray odontology units calculate avarage level individual effective radiation dose corresponding groups teeth: upper and lover jours are calculated.

  16. Monte Carlo study of radiation dose enhancement by gadolinium in megavoltage and high dose rate radiotherapy.

    Directory of Open Access Journals (Sweden)

    Daniel G Zhang

    Full Text Available MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitative investigation of high-Z material Gd-induced dose enhancement in megavoltage external beam photon therapy. BEAMnrc, a radiotherapy Monte Carlo simulation package, was used to calculate dose enhancement as a function of Gd concentration. Published phase space files for the TrueBeam flattening filter free (FFF and conventional flattened 6MV photon beams were used. High dose rate (HDR brachytherapy with Ir-192 source was also investigated as a reference. The energy spectra difference caused a dose enhancement difference between the two beams. Since the Ir-192 photons have lower energy yet, the photoelectric effect in the presence of Gd leads to even higher dose enhancement in HDR. At depth of 1.8 cm, the percent mean dose enhancement for the FFF beam was 0.38±0.12, 1.39±0.21, 2.51±0.34, 3.59±0.26, and 4.59±0.34 for Gd concentrations of 1, 5, 10, 15, and 20 mg/mL, respectively. The corresponding values for the flattened beam were 0.09±0.14, 0.50±0.28, 1.19±0.29, 1.68±0.39, and 2.34±0.24. For Ir-192 with direct contact, the enhanced were 0.50±0.14, 2.79±0.17, 5.49±0.12, 8.19±0.14, and 10.80±0.13. Gd-containing materials used in MRI as contrast agents can also potentially serve as radiosensitizers in radiotherapy. This study demonstrates that Gd can be used to enhance radiation dose in target volumes not only in HDR brachytherapy, but also in 6 MV FFF external beam radiotherapy, but higher than the currently used clinical concentration (>5 mg/mL would be needed.

  17. Monte Carlo study of radiation dose enhancement by gadolinium in megavoltage and high dose rate radiotherapy.

    Science.gov (United States)

    Zhang, Daniel G; Feygelman, Vladimir; Moros, Eduardo G; Latifi, Kujtim; Zhang, Geoffrey G

    2014-01-01

    MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd)-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitative investigation of high-Z material Gd-induced dose enhancement in megavoltage external beam photon therapy. BEAMnrc, a radiotherapy Monte Carlo simulation package, was used to calculate dose enhancement as a function of Gd concentration. Published phase space files for the TrueBeam flattening filter free (FFF) and conventional flattened 6MV photon beams were used. High dose rate (HDR) brachytherapy with Ir-192 source was also investigated as a reference. The energy spectra difference caused a dose enhancement difference between the two beams. Since the Ir-192 photons have lower energy yet, the photoelectric effect in the presence of Gd leads to even higher dose enhancement in HDR. At depth of 1.8 cm, the percent mean dose enhancement for the FFF beam was 0.38±0.12, 1.39±0.21, 2.51±0.34, 3.59±0.26, and 4.59±0.34 for Gd concentrations of 1, 5, 10, 15, and 20 mg/mL, respectively. The corresponding values for the flattened beam were 0.09±0.14, 0.50±0.28, 1.19±0.29, 1.68±0.39, and 2.34±0.24. For Ir-192 with direct contact, the enhanced were 0.50±0.14, 2.79±0.17, 5.49±0.12, 8.19±0.14, and 10.80±0.13. Gd-containing materials used in MRI as contrast agents can also potentially serve as radiosensitizers in radiotherapy. This study demonstrates that Gd can be used to enhance radiation dose in target volumes not only in HDR brachytherapy, but also in 6 MV FFF external beam radiotherapy, but higher than the currently used clinical concentration (>5 mg/mL) would be needed.

  18. Is There a Dose-Response Relationship for Heart Disease With Low-Dose Radiation Therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eugene [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Corbett, James R. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Moran, Jean M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Griffith, Kent A. [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Marsh, Robin B.; Feng, Mary; Jagsi, Reshma; Kessler, Marc L. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Ficaro, Edward C. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Pierce, Lori J., E-mail: ljpierce@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-03-15

    Purpose: To quantify cardiac radiation therapy (RT) exposure using sensitive measures of cardiac dysfunction; and to correlate dysfunction with heart doses, in the setting of adjuvant RT for left-sided breast cancer. Methods and Materials: On a randomized trial, 32 women with node-positive left-sided breast cancer underwent pre-RT stress single photon emission computed tomography (SPECT-CT) myocardial perfusion scans. Patients received RT to the breast/chest wall and regional lymph nodes to doses of 50 to 52.2 Gy. Repeat SPECT-CT scans were performed 1 year after RT. Perfusion defects (PD), summed stress defects scores (SSS), and ejection fractions (EF) were evaluated. Doses to the heart and coronary arteries were quantified. Results: The mean difference in pre- and post-RT PD was −0.38% ± 3.20% (P=.68), with no clinically significant defects. To assess for subclinical effects, PD were also examined using a 1.5-SD below the normal mean threshold, with a mean difference of 2.53% ± 12.57% (P=.38). The mean differences in SSS and EF before and after RT were 0.78% ± 2.50% (P=.08) and 1.75% ± 7.29% (P=.39), respectively. The average heart Dmean and D95 were 2.82 Gy (range, 1.11-6.06 Gy) and 0.90 Gy (range, 0.13-2.17 Gy), respectively. The average Dmean and D95 to the left anterior descending artery were 7.22 Gy (range, 2.58-18.05 Gy) and 3.22 Gy (range, 1.23-6.86 Gy), respectively. No correlations were found between cardiac doses and changes in PD, SSS, and EF. Conclusions: Using sensitive measures of cardiac function, no clinically significant defects were found after RT, with the average heart Dmean <5 Gy. Although a dose response may exist for measures of cardiac dysfunction at higher doses, no correlation was found in the present study for low doses delivered to cardiac structures and perfusion, SSS, or EF.

  19. Is There a Dose-Response Relationship for Heart Disease With Low-Dose Radiation Therapy?

    International Nuclear Information System (INIS)

    Purpose: To quantify cardiac radiation therapy (RT) exposure using sensitive measures of cardiac dysfunction; and to correlate dysfunction with heart doses, in the setting of adjuvant RT for left-sided breast cancer. Methods and Materials: On a randomized trial, 32 women with node-positive left-sided breast cancer underwent pre-RT stress single photon emission computed tomography (SPECT-CT) myocardial perfusion scans. Patients received RT to the breast/chest wall and regional lymph nodes to doses of 50 to 52.2 Gy. Repeat SPECT-CT scans were performed 1 year after RT. Perfusion defects (PD), summed stress defects scores (SSS), and ejection fractions (EF) were evaluated. Doses to the heart and coronary arteries were quantified. Results: The mean difference in pre- and post-RT PD was −0.38% ± 3.20% (P=.68), with no clinically significant defects. To assess for subclinical effects, PD were also examined using a 1.5-SD below the normal mean threshold, with a mean difference of 2.53% ± 12.57% (P=.38). The mean differences in SSS and EF before and after RT were 0.78% ± 2.50% (P=.08) and 1.75% ± 7.29% (P=.39), respectively. The average heart Dmean and D95 were 2.82 Gy (range, 1.11-6.06 Gy) and 0.90 Gy (range, 0.13-2.17 Gy), respectively. The average Dmean and D95 to the left anterior descending artery were 7.22 Gy (range, 2.58-18.05 Gy) and 3.22 Gy (range, 1.23-6.86 Gy), respectively. No correlations were found between cardiac doses and changes in PD, SSS, and EF. Conclusions: Using sensitive measures of cardiac function, no clinically significant defects were found after RT, with the average heart Dmean <5 Gy. Although a dose response may exist for measures of cardiac dysfunction at higher doses, no correlation was found in the present study for low doses delivered to cardiac structures and perfusion, SSS, or EF

  20. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, R.P.

    1991-01-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examining the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute [gamma]-radiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. It was concluded that oligodendrocytes in irradiated cultures had significantly lower functional capacity than did unirradiated controls. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. At DIC 14, the group irradiated in a single fraction had significantly lower oligodendrocyte counts than any group given split doses; all irradiated cultures had marked depression of MBP synthesis, but to significant differences referable to time interval between doses. At DIC 21, cultures irradiated at intervals of 0 h to 2 h had similar oligodendrocyte counts to one another, but these counts were significantly lower than in cultures irradiated at intervals of 4 h to 6 h; MBP levels remained depressed at DIC 21 for all irradiated cultures. The oligodendrocyte response to dose rate (0.03 to 1.97 Gy/min) was evaluated at DIC 14 and DIC 21. Exposure at 0.03 Gy/min suppressed oligodendrocyte counts at DIC 21 less than did higher dose rates in 5-Gy irradiated cultures.

  1. Galactic cosmic ray induced radiation dose on terrestrial exoplanets

    CERN Document Server

    Atri, Dimitra; Griessmeier, Jean-Mathias

    2013-01-01

    This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground and space based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets, falling in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in case of super earths. Such exoplanets are subjected to a high flux of Galactic Cosmic Rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin, which strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another fac...

  2. Doses in radiation accidents investigated by chromosome aberration analysis

    International Nuclear Information System (INIS)

    Results from cytogenetic investigations into 55 cases of suspected over-exposure to radiation during 1977 are reviewed. This report is the seventh in an annual series (previous results were published in NRPB-R5, R10, R23, R35, R41 and R57) which together contain data on 327 studies. Results from all investigations have been pooled for general analysis. Brief accounts are given in an appendix of the circumstances behind the past year's investigations and, where possible, physical estimates of dose have been included for comparison. Two cases are described in more detail: the first concerned a non-classified worker who put an iridium-192 source in his pocket and took it home; and the second involved the accidental contamination of two people with tritium gas. In a second appendix, the confidence limits on cytogenetic dosimetry for X- and γ-ray over-exposures are given and the derivation of these limits is discussed. (author)

  3. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    International Nuclear Information System (INIS)

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain

  4. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, R.P.

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute {gamma}-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  5. The interaction of natural background gamma radiation with depleted uranium micro-particles in the human body.

    Science.gov (United States)

    Pattison, John E

    2013-03-01

    In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm(3) of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant. PMID:23295360

  6. The effective dose equivalent from external and internal radiation

    International Nuclear Information System (INIS)

    The various sources of low-level ionizing radiation are discussed and compared in terms of mean effective dose equivalent to man. For the most nonoccupationally exposed individuals, natural sources given the dominating contribution to the effective dose equivalent. The size of this contribution is strongly dependent on human activities. Natural sources contribution on average 2.4 mSV per year, of which half is due to irradiation of lungs and airways from short lived radon daughters present in indoor air. In Sweden this radon daughter contribution is considerably higher and contributes a mean of 3 mSv per year, thus giving a total contribution from natural radiation of about 4 mSV per year. In extreme cases, radon daughter contributions of several hundreds of mSv per year may be reached. Medical exposure, mainly diagnostic X-rays, contributes 0.4-1 mSv per year both in Sweden and as a world average. The testing of nuclear weapons in the atmosphere has given 1-2 mSv to each person in the world as a mean. The contribution from the routine operation of nuclear reactors is insignificant. The reactor accident in Chernobyl resulted in widely varying exposures of the European population. The average for Sweden is estimated to be 0.1 mSv during the first year and about 1 mSv during a 50-year period. For groups of Swedes who eat a considerable amount of game this contribution will be 10 times higher, and for the Lapps who breed reindeer in the most contaminated areas, typical values of 20-70 mSv and extreme values of about 1 Sv may be reached in 50 years. This means that the Chernobyl reactor accident for several years will be their dominating source of irradiation

  7. A Systems Genetic Approach to Identify Low Dose Radiation-Induced Lymphoma Susceptibility/DOE2013FinalReport

    Energy Technology Data Exchange (ETDEWEB)

    Balmain, Allan [University of California, San Francisco; Song, Ihn Young [University of California, San Francisco

    2013-05-15

    The ultimate goal of this project is to identify the combinations of genetic variants that confer an individual's susceptibility to the effects of low dose (0.1 Gy) gamma-radiation, in particular with regard to tumor development. In contrast to the known effects of high dose radiation in cancer induction, the responses to low dose radiation (defined as 0.1 Gy or less) are much less well understood, and have been proposed to involve a protective anti-tumor effect in some in vivo scientific models. These conflicting results confound attempts to develop predictive models of the risk of exposure to low dose radiation, particularly when combined with the strong effects of inherited genetic variants on both radiation effects and cancer susceptibility. We have used a Systems Genetics approach in mice that combines genetic background analysis with responses to low and high dose radiation, in order to develop insights that will allow us to reconcile these disparate observations. Using this comprehensive approach we have analyzed normal tissue gene expression (in this case the skin and thymus), together with the changes that take place in this gene expression architecture a) in response to low or high- dose radiation and b) during tumor development. Additionally, we have demonstrated that using our expression analysis approach in our genetically heterogeneous/defined radiation-induced tumor mouse models can uniquely identify genes and pathways relevant to human T-ALL, and uncover interactions between common genetic variants of genes which may lead to tumor susceptibility.

  8. Fluoroscopically Guided Percutaneous Vertebroplasty: Assessment of Radiation Doses and Implementation of Procedural Routines to Reduce Operator Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wrangel, A. von; Cederblad, Aa. (Dept. of Medical Physics and Biomedical Engineering, Sahlgrenska Univ. Hospital, Goeteborg (Sweden)); Rodriguez-Catarino, M. (Dept. of Radiology, Sahlgrenska Univ. Hospital, Goeteborg (Sweden))

    2009-06-15

    Background: Percutaneous vertebroplasty (PVP) is a fluoroscopically guided procedure for the treatment of painful vertebral compression fractures and metastases. Routine legal personal dosimetry repeatedly showed dosimeter doses exceeding 1 mSv/month for the only radiologist performing PVP at our hospital. Based on the nature of the procedure, this raised concern about potentially high doses to the eyes and fingers. Purpose: To assess radiation doses to the operator, and to evaluate possibilities for dose reduction. Material and Methods: Measurements of scattered radiation in simulated thoracic and lumbar PVP procedures were performed using two anatomical phantoms - thorax and lower trunk - and a radiation survey meter. The standard position of the operator was determined as being 50 cm from the irradiated area of the phantom. The protection ability of lead-free gloves was evaluated during the simulations. Operator doses to fingers and eyes during 10 clinical PVP procedures performed by a single operator were measured, and the annual dose was calculated. Routine personal dosimetry was performed using thermoluminescent dosimeter (TLD) badges beneath the lead apron, and doses to fingers and eyes were measured with small TLD tablets. Results: During simulations, the measured operator dose rate arising from lateral fluoroscopy at the thorax and lumbar level was reduced by a factor of 4-5 when the X-ray tube was moved from the operator's side of the patient to the opposite side. Wearing protective gloves reduced radiation dose to the hands by 30-40%. The mean doses arising from the 10 clinical PVP procedures to the right and left hands, using protection gloves, were 2.0 mSv and 4.8 mSv, respectively. The mean dose to the eyes was 0.23 mSv. The mean effective dose to the patients was 12 mSv. Conclusion: Placing the X-ray tube on the side of the patient opposite to the operator and the use of radiation protection gloves significantly reduces radiation exposure to the

  9. Involved-nodal radiation therapy leads to lower doses to critical organs-at-risk compared to involved-field radiation therapy

    International Nuclear Information System (INIS)

    Background: Involved field radiotherapy (IFRT) after cytotoxic chemotherapy has become the standard of care in treating pediatric patients with Hodgkin lymphoma. However, recent interest in shrinking the treatment volume to involved node radiotherapy (INRT) may allow lower doses to critical organ structures. We dosimetrically compared IFRT and INRT treatment approaches. Methods: INRT treatment plans were retrospectively constructed from 17 consecutively treated pediatric patients identified with Hodgkin lymphoma who had been previously treated with conventional IFRT. The radiation doses delivered to organs-at-risk (OARs) with virtual INRT treatment plans based on INRT field design were then compared to the original IFRT treatment plans. Metrics for comparison included mean doses to organs and volumes of organ receiving at least 50% of the original prescription dose (V50%). A one-tailed, paired t-test was then performed to verify statistical significance at an alpha level of 0.05. Results: All organs at risk compared in this investigation (kidneys, heart, thyroid, parotids, and lungs) had significantly lower doses of radiation with INRT when compared to IFRT (p < 0.05). Furthermore, the volume of the breast receiving at least 50% of the initial prescription dose was statistically lower in the INRT plans. Conclusions: Utilizing the concept of INRT results in a reduction of radiation dose to critical organ structures in pediatric patients with Hodgkin lymphoma when compared to the more traditional method of IFRT

  10. Association of elevated radiation dose with mortality in patients with acute myocardial infarction undergoing percutaneous coronary intervention

    Energy Technology Data Exchange (ETDEWEB)

    Parikh, Puja B.; Prakash, Sheena; Tahir, Usman; Kort, Smadar; Gruberg, Luis; Jeremias, Allen, E-mail: allen.jeremias@stonybrook.edu

    2014-09-15

    Objectives: This study sought to identify clinical and procedural predictors of elevated radiation dose received by patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) and to determine if elevated radiation dose was predictive of mortality in this population. Background: Little data exist regarding the impact of excessive radiation burden on clinical outcomes in patients undergoing PCI. Methods: The study population included 1,039 patients who underwent PCI for an AMI between January 1, 2007 and December 31, 2008 at an academic tertiary care teaching hospital. Cumulative skin dose (measured in milligray [mGy]) was selected as a measurement of patient radiation burden. Clinical and procedural variables were analyzed in multiple logistic and linear regression models to determine predictors of higher skin dose, and its impact was evaluated on all-cause intermediate-term mortality at two years. Results: Median skin dose was 2120 mGy (IQR 1379–3190 mGy) in the overall population, of which 153 (20.8%) patients received an elevated skin dose (defined as a skin dose > 4,000 mGy). Independent predictors of elevated skin dose included male gender, obesity, multivessel intervention, and presentation with a non-ST-elevation MI (NSTEMI) versus an ST-elevation MI (STEMI). Increased skin dose was not predictive of intermediate-term mortality by multivariate analysis in the overall population or in either subgroup of STEMI and NSTEMI. Conclusions: In this contemporary observational study examining patients with AMI undergoing PCI, male gender, obesity, multivessel intervention, and presentation with a NSTEMI were associated with increased radiation exposure.

  11. On the radiative and thermodynamic properties of the Cosmic Microwave Background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Use formulas to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density in the finite range of frequencies are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.728 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant are calculated. In the case of the dipole spectrum, the constants a and the Stefan-Bol...

  12. Radiation Sialadenitis Induced by High-dose Radioactive Iodine Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Shin Young; Lee, Jaetae [Kyungpook National University Hospital, Daegu (Korea, Republic of)

    2010-06-15

    Radioactive iodine ({sup 131}I) is accumulated in the thyroid tissue and plays an important role in the treatment of differentiated papillary and follicular cancers after thyroidectomy. Simultaneously, {sup 131}I is concentrated in the salivary glands and secreted into the saliva. Dose-related damage to the salivary parenchyma results from the {sup 131}I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of {sup 131}I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, candidiasis, and neoplasia. Prevention of {sup 131}I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration. Recently interventional sialoendoscopy has been introduced an effective tool for the management of patients with {sup 131}I-induced sialadenitis that is unresponsive to medical treatment.

  13. Radiation Sialadenitis Induced by High-dose Radioactive Iodine Therapy

    International Nuclear Information System (INIS)

    Radioactive iodine (131I) is accumulated in the thyroid tissue and plays an important role in the treatment of differentiated papillary and follicular cancers after thyroidectomy. Simultaneously, 131I is concentrated in the salivary glands and secreted into the saliva. Dose-related damage to the salivary parenchyma results from the 131I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of 131I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, candidiasis, and neoplasia. Prevention of 131I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration. Recently interventional sialoendoscopy has been introduced an effective tool for the management of patients with 131I-induced sialadenitis that is unresponsive to medical treatment.

  14. Dose-dependent hepatic transcriptional responses in Atlantic salmon (Salmo salar) exposed to sublethal doses of gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Song, You, E-mail: you.song@niva.no [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo (Norway); Salbu, Brit; Teien, Hans-Christian; Heier, Lene Sørlie [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Rosseland, Bjørn Olav [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Norwegian University of Life Sciences (NMBU), Department of Ecology and Natural Resource Management, P.O. Box 5003, N-1432 Ås (Norway); Tollefsen, Knut Erik [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo (Norway)

    2014-11-15

    Highlights: • First study on early stress responses in salmon exposed to low-dose gamma radiation. • Dramatic dose-dependent transcriptional responses characterized. • Multiple modes of action proposed for gamma radiation. - Abstract: Due to the production of free radicals, gamma radiation may pose a hazard to living organisms. The high-dose radiation effects have been extensively studied, whereas the ecotoxicity data on low-dose gamma radiation is still limited. The present study was therefore performed using Atlantic salmon (Salmo salar) to characterize effects of low-dose (15, 70 and 280 mGy) gamma radiation after short-term (48 h) exposure. Global transcriptional changes were studied using a combination of high-density oligonucleotide microarrays and quantitative real-time reverse transcription polymerase chain reaction (qPCR). Differentially expressed genes (DEGs; in this article the phrase gene expression is taken as a synonym of gene transcription, although it is acknowledged that gene expression can also be regulated, e.g., at protein stability and translational level) were determined and linked to their biological meanings predicted using both Gene Ontology (GO) and mammalian ortholog-based functional analyses. The plasma glucose level was also measured as a general stress biomarker at the organism level. Results from the microarray analysis revealed a dose-dependent pattern of global transcriptional responses, with 222, 495 and 909 DEGs regulated by 15, 70 and 280 mGy gamma radiation, respectively. Among these DEGs, only 34 were commonly regulated by all radiation doses, whereas the majority of differences were dose-specific. No GO functions were identified at low or medium doses, but repression of DEGs associated with GO functions such as DNA replication, cell cycle regulation and response to reactive oxygen species (ROS) were observed after 280 mGy gamma exposure. Ortholog-based toxicity pathway analysis further showed that 15 mGy radiation

  15. Palliative radiation treatment of cutaneous mycosis fungoides - a dose response

    Energy Technology Data Exchange (ETDEWEB)

    Cotter, G.W.; Baglan, R.J.; Wasserman, T.H.; Mill, W.

    1983-10-01

    Between 1966 and 1981, 20 patients (191 lesions) underwent palliative radiation therapy for control of biopsy-proven cutaneous mycosis fungoides. Six patients (47 lesions) and an additional 34 lesions from the remaining 14 patients with complete response to treatment were excluded from the study because of follow-up of less than one year. Included in the remaining 110 lesions were all recurrences and all partial responses. The modalities for treatment included superficial X rays, Cobalt-60 or electron beam irradiation. The total tumor doses employed ranged from 600-4000 cGy. The 110 lesions (14 patients) were retrospectively analyzed to determine the dose required for local control of the lesions. Fifty-three percent of the lesions were classified as plaques, 20% as tumors less than or equal to 3 cm in diameter, and 27% as tumors > 3 cm in diameter. Complete response to treatment was observed in 95% of the plaque lesions, 95% of the tumors less than or equal to 3 cm in diameter and 93% of tumor > 3 cm in diameter. A complete response to treatment was noted in all lesions receiving greater than 2000 cGy. In the total population of lesions having a complete response, a local infield recurrence rate of 42% was noted in the group receiving less than or equal to 1000 cGy, 32% in those receiving 1001-2000 cGy, 21% in those receiving 2001-3000 cGy, and 0% in the group receiving > 3000 cGy. The data from this study indicate that tumor doses equivalent to at least 3000 cGy at 200 cGy per fraction, five fractions per week (TDF greater than or equal to) are needed for adquate local control of cutaneous mycosis fungoides lesions.

  16. Dosimetry for quantitative analysis of low dose ionizing radiation effects on humans in radiation therapy patients

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, J; Stern, R L; Daly, T P; Schwieter, C W; Jones, G E; Arnold, M L; Hartmann-Siantar, C L; Goldberg, Z

    2004-04-20

    We have successfully developed a practical approach to predicting the location of skin surface dose at potential biopsy sites that receive 1 cGy and 10 cGy, respectively, in support of in vivo biologic dosimetry in humans. This represents a significant technical challenge as the sites lie on the patient surface out side the radiation fields. The PEREGRINE Monte Carlo simulation system was used to model radiation dose delivery and TLDs were used for validation on a phantom and confirmation during patient treatment. In the developmental studies the Monte Carlo simulations consistently underestimated the dose at the biopsy site by approximately 15% for a realistic treatment configuration, most likely due to lack of detail in the simulation of the linear accelerator outside the main beam line. Using a single, thickness-independent correction factor for the clinical calculations, the average of 36 measurements for the predicted 1 cGy point was 0.985 cGy (standard deviation: 0.110 cGy) despite patient breathing motion and other real world challenges. Since the 10 cGy point is situated in the region of high dose gradient at the edge of the field, patient motion had a greater effect and the six measured points averaged 5.90 cGy (standard deviation: 1.01 cGy), a difference that is equivalent to approximately a 6 mm shift on the patient's surface.

  17. Dosimetry for quantitative analysis of low dose ionizing radiation effects on humans in radiation therapy patients

    International Nuclear Information System (INIS)

    We have successfully developed a practical approach to predicting the location of skin surface dose at potential biopsy sites that receive 1 cGy and 10 cGy, respectively, in support of in vivo biologic dosimetry in humans. This represents a significant technical challenge as the sites lie on the patient surface out side the radiation fields. The PEREGRINE Monte Carlo simulation system was used to model radiation dose delivery and TLDs were used for validation on a phantom and confirmation during patient treatment. In the developmental studies the Monte Carlo simulations consistently underestimated the dose at the biopsy site by approximately 15% for a realistic treatment configuration, most likely due to lack of detail in the simulation of the linear accelerator outside the main beam line. Using a single, thickness-independent correction factor for the clinical calculations, the average of 36 measurements for the predicted 1 cGy point was 0.985 cGy (standard deviation: 0.110 cGy) despite patient breathing motion and other real world challenges. Since the 10 cGy point is situated in the region of high dose gradient at the edge of the field, patient motion had a greater effect and the six measured points averaged 5.90 cGy (standard deviation: 1.01 cGy), a difference that is equivalent to approximately a 6 mm shift on the patient's surface

  18. The Very High Background Radiation Area in Ramsar, Iran: Public Health Risk or Signal for a Regulatory Paradigm Shift?

    Energy Technology Data Exchange (ETDEWEB)

    Karam, P. Andrew [Univ. of Rochester, Rochester, NY (United States); Mortazavi, S.M. Javad [Rafsanjan Univ. of Medical Sciences (Iran, Islamic Republic of). Medical Physics Dept.

    2001-07-01

    Ramsar, a city on the Caspian Sea in northern Iran hosts the highest measured natural background radiation levels in the world. These are due to the local geology and hydrogeology and, in some places, deliver radiation doses far in excess of those recommended for radiation workers. A population of about 2000 is exposed to average annual radiation levels of 10.2 mGy/yr and the highest recorded doses are about 260 mGy/yr. These high radiation levels are due to the deposition of {sup 226}Ra in local rocks and, because these rocks are used in the construction of many local houses, interior radiation levels are often similar to those found outside. The presence of areas such as Ramsar raises an interesting public health policy question: Is it necessary to relocate the inhabitants to areas of lower natural background radiation levels in the interests of public health? According to the linear, no-threshold (LNT) hypothesis, there is no doubt that relocating the population of Ramsar will result in a reduction in cancer incidence. Therefore, under any reasonable policy based on the LNT hypothesis, the public health is best served by relocating many of Ramsar's inhabitants to other areas along the Caspian Sea. At present, there is no reliable epidemiological data on cancer incidence among the inhabitants of Ramsar's high background radiation areas (HBRAs), but local physicians feel that local cancer incidence rates are lower than in neighboring cities. Furthermore, preliminary results indicate that there is a statistically significant radio adaptation in the inhabitants of Ramsar. Interestingly, it seems that the frequency of chromosome aberrations in the lymphocytes of the inhabitants of Ramsar is no higher than the control areas. This important finding suggests that the cancer rate in Ramsar should be no higher than in other comparable parts of Iran. In other HBRAs such as Yangjiang, China it has been reported that mortality from all cancers and those from

  19. The Very High Background Radiation Area in Ramsar, Iran: Public Health Risk or Signal for a Regulatory Paradigm Shift?

    International Nuclear Information System (INIS)

    Ramsar, a city on the Caspian Sea in northern Iran hosts the highest measured natural background radiation levels in the world. These are due to the local geology and hydrogeology and, in some places, deliver radiation doses far in excess of those recommended for radiation workers. A population of about 2000 is exposed to average annual radiation levels of 10.2 mGy/yr and the highest recorded doses are about 260 mGy/yr. These high radiation levels are due to the deposition of 226Ra in local rocks and, because these rocks are used in the construction of many local houses, interior radiation levels are often similar to those found outside. The presence of areas such as Ramsar raises an interesting public health policy question: Is it necessary to relocate the inhabitants to areas of lower natural background radiation levels in the interests of public health? According to the linear, no-threshold (LNT) hypothesis, there is no doubt that relocating the population of Ramsar will result in a reduction in cancer incidence. Therefore, under any reasonable policy based on the LNT hypothesis, the public health is best served by relocating many of Ramsar's inhabitants to other areas along the Caspian Sea. At present, there is no reliable epidemiological data on cancer incidence among the inhabitants of Ramsar's high background radiation areas (HBRAs), but local physicians feel that local cancer incidence rates are lower than in neighboring cities. Furthermore, preliminary results indicate that there is a statistically significant radio adaptation in the inhabitants of Ramsar. Interestingly, it seems that the frequency of chromosome aberrations in the lymphocytes of the inhabitants of Ramsar is no higher than the control areas. This important finding suggests that the cancer rate in Ramsar should be no higher than in other comparable parts of Iran. In other HBRAs such as Yangjiang, China it has been reported that mortality from all cancers and those from leukemia, breast and

  20. Estimation of doses to patients with chronic radiation sickness from external occupational exposure

    International Nuclear Information System (INIS)

    The doses to patients with chronic radiation sickness who had engaged in diagnostic radiology have been estimated according to the radiation work load, type and capacity of X-ray equipment, protection conditions, data of nationwide survey on doses to X-ray workers in China, or the data of dose monitoring in working places. Based on the activities of radium sources, time taken up in performing radium therapy, distance to radium sources and radiation work load, the doses to patients who had engaged in radium therapy have been estimated. The results of estimated average doses for 29 cases of chronic radiation sickness are given. Their average red marrow dose, trunk dose and effective dose equivalent are 1.3 Gy, 1.2 Gy and 1.6 Sv, respectively

  1. Radiation dose measurements during kilovoltage-cone beam computed tomography imaging in radiotherapy

    Directory of Open Access Journals (Sweden)

    A Sathish Kumar

    2016-01-01

    Conclusion: Radiation dose to the eye, breast, and the surface of the pelvis have been arrived at during CBCT. The doses measured on patients agreed closely with those measured on humanoid phantom and with published values.

  2. A meta-analysis of leukaemia risk from protracted exposure to low-dose gamma radiation

    OpenAIRE

    Daniels, R D; Schubauer-Berigan, M K

    2010-01-01

    Context More than 400 000 workers annually receive a measurable radiation dose and may be at increased risk of radiation-induced leukaemia. It is unclear whether leukaemia risk is elevated with protracted, low-dose exposure. Objective We conducted a meta-analysis examining the relationship between protracted low-dose ionising radiation exposure and leukaemia. Data sources Reviews by the National Academies and United Nations provided a summary of informative studies published before 2005. PubM...

  3. The measurement of radiation doses from P32 chromic phosphate therapy of the peritoneum using SPECT

    International Nuclear Information System (INIS)

    Single photon emission computed tomogrpahy (SPECT) has been shown to be of value in estimating the radiation dose to the peritoneum from 32P therapy. Simple dosimetry calculations, assuming uniform irradiation of tissue, indicate that radiation doses of proportional40 Gy to the peritoneal surface are achieved. However, the images show that the radionuclide distribution is non-uniform, giving rise to radiation dose variations of at least a factor of 10. (orig.)

  4. The Inhibitory Effects of Low-Dose Ionizing Radiation in IgE-Mediated Allergic Responses.

    Directory of Open Access Journals (Sweden)

    Hae Mi Joo

    Full Text Available Ionizing radiation has different biological effects according to dose and dose rate. In particular, the biological effect of low-dose radiation is unclear. Low-dose whole-body gamma irradiation activates immune responses in several ways. However, the effects and mechanism of low-dose radiation on allergic responses remain poorly understood. Previously, we reported that low-dose ionizing radiation inhibits mediator release in IgE-mediated RBL-2H3 mast cell activation. In this study, to have any physiological relevance, we investigated whether low-dose radiation inhibits allergic responses in activated human mast cells (HMC-1(5C6 and LAD2 cells, mouse models of passive cutaneous anaphylaxis and the late-phase cutaneous response. High-dose radiation induced cell death, but low-dose ionizing radiation of <0.5 Gy did not induce mast cell death. Low-dose ionizing radiation that did not induce cell death significantly suppressed mediator release from human mast cells (HMC-1(5C6 and LAD2 cells that were activated by antigen-antibody reaction. To determine the inhibitory mechanism of mediator released by low-dose ionizing radiation, we examined the phosphorylation of intracellular signaling molecules such as Lyn, Syk, phospholipase Cγ, and protein kinase C, as well as the intracellular free Ca2+ concentration ([Ca2+]i. The phosphorylation of signaling molecules and [Ca2+]i following stimulation of FcεRI receptors was inhibited by low dose ionizing radiation. In agreement with its in vitro effect, ionizing radiation also significantly inhibited inflammatory cells infiltration, cytokine mRNA expression (TNF-α, IL-4, IL-13, and symptoms of passive cutaneous anaphylaxis reaction and the late-phase cutaneous response in anti-dinitrophenyl IgE-sensitized mice. These results indicate that ionizing radiation inhibits both mast cell-mediated immediate- and delayed-type allergic reactions in vivo and in vitro.

  5. Optimization of paediatric radiation doses with CR systems

    International Nuclear Information System (INIS)

    Full text: Radiation protection of paediatric patients is a primary objective in paediatric radiology due the higher life expectance of the little patients undergoing radiology examinations and due to the higher radiosensitivity of tissues. Aim of this work is the study of the optimization process in paediatric doses needed after the recent installation of a new Computed Radiography System in the Radiology of the Meyer paediatric Hospital, in Florence, Italy. This process involves both the use of new dedicated digitizer (Agfa DX-S) and elaboration software (Agfa NX2.0). The choice of the DX-S systems has been performed in consideration of high resolution (Scanhead technology - DirectriX detector), image sharpness and portability of the cassettes that make DX-S ideal in paediatric applications as neonatal intensive care. The NX software for image processing has been installed with the 'Paediatric' licence that optimizes paediatric images especially for exposures of premature newborns. Paediatric NX automatically selects the paediatric age group, depending on the patient's birth date. Each age group contains enhanced algorithms and settings adapted to age group, for optimized visibility of fine details. All the CR system has been accepted by mean of quality control acceptance tool AGFA AutoQC2, and all the automatic exposure control devices installed on radiographic devices were previously calibrated in accordance to literature with signal to noise vs dose considerations [S. Mazzocchi et al. 'AEC set-up optimization with computed radiography imaging' Radiat. Prot. Dosim. 117, 169-173 2005]. Paediatric patients were then divided into age-weight categories and the Entrance Surface Doses (ESD) were calculated by output x-rays measurements. ESD for thorax examinations were correlated to the image evaluations performed by experienced radiologists following European Guidelines on quality criteria for diagnostic radiographic images in paediatrics (EUR 16261, European

  6. A technique for multi-dimensional optimization of radiation dose, contrast dose, and image quality in CT imaging

    Science.gov (United States)

    Sahbaee, Pooyan; Abadi, Ehsan; Sanders, Jeremiah; Becchetti, Marc; Zhang, Yakun; Agasthya, Greeshma; Segars, Paul; Samei, Ehsan

    2016-03-01

    The purpose of this study was to substantiate the interdependency of image quality, radiation dose, and contrast material dose in CT towards the patient-specific optimization of the imaging protocols. The study deployed two phantom platforms. First, a variable sized phantom containing an iodinated insert was imaged on a representative CT scanner at multiple CTDI values. The contrast and noise were measured from the reconstructed images for each phantom diameter. Linearly related to iodine-concentration, contrast to noise ratio (CNR), was calculated for different iodine-concentration levels. Second, the analysis was extended to a recently developed suit of 58 virtual human models (5D-XCAT) with added contrast dynamics. Emulating a contrast-enhanced abdominal image procedure and targeting a peak-enhancement in aorta, each XCAT phantom was "imaged" using a CT simulation platform. 3D surfaces for each patient/size established the relationship between iodine-concentration, dose, and CNR. The Sensitivity of Ratio (SR), defined as ratio of change in iodine-concentration versus dose to yield a constant change in CNR was calculated and compared at high and low radiation dose for both phantom platforms. The results show that sensitivity of CNR to iodine concentration is larger at high radiation dose (up to 73%). The SR results were highly affected by radiation dose metric; CTDI or organ dose. Furthermore, results showed that the presence of contrast material could have a profound impact on optimization results (up to 45%).

  7. Basic research of the relationship between irradiation dose and volume in radiation-induced pulmonary injury

    Institute of Scientific and Technical Information of China (English)

    PANG Qing-song; WANG Ping; WANG Jing; WANG Wei; WANG Jun; YUAN Zhi-yong

    2009-01-01

    Background Irradiation dose and volume are the major physical factors of radiation-induced lung injury.The study investigated the relationships between the irradiation dose and volume in radiation-induced lung injury by setting up a model of graded volume irradiation of the rat lung.Methods Animals were randomly assigned to three groups.The ELEKTA precise 2.03 treatment plan system was applied to calculate the irradiation dose and volume.The treatment plan for the three groups was:group 1 received a "high dose to a small volume" (25% volume group) with the mean irradiation volume being 1.748 cm3 (25% lung volume);the total dose and mean lung dose (MLD) were 4610 cGy and 2006 cGy,respectively (bilateral AP-PA fields,source to axis distance (SAD)=100 cm,6MVX,single irradiation);Group 2 received a "low dose to a large volume" (100% volume group) with the mean irradiation volume being 6.99 cm3 (100% lung volume);the total dose was 1153 cGy.MLD was 2006 cGy,which was the same as that of group 1 (bilateral AP-PA fields,SAD = 100 cm,6MVX,single irradiation);Group 3 was a control group.With the exception of receiving no irradiation,group 3 had rest steps that were the same as those of the experimental groups.After irradiation,functional,histopathological,and CT changes were compared every two weeks till the 16th week.Results Functionally,after irradiation breath rate (BR) increases were observed in both group 1 and group 2,especially during the period of 6th-8th weeks.The changes of BR in the 100% volume group were earlier and faster.For the 25% volume group,although pathology was more severe,hardly any obvious increase in BR was observed.Radiographic changes were observed during the early period (the 4th week) and the most obvious changes manifested during the mediated period (the 8th week).The extensiveness of high density and the decreased lung permeability were presented in the 100% volume group,and ground glass opacity and patchy consolidation were presented in the 25

  8. REDUCING STRAY RADIATION DOSE FOR A PEDIATRIC PATIENT RECEIVING PROTON CRANIOSPINAL IRRADIATION

    OpenAIRE

    Taddei, Phillip J; Mirkovic, Dragan; Fontenot, Jonas D.; Giebeler, Annelise; Zheng, Yuanshui; Titt, Uwe; Woo, Shiao; Newhauser, Wayne D.

    2009-01-01

    The aim of this study was to quantify stray radiation dose from neutrons emanating from a proton treatment unit and to evaluate methods of reducing this dose for a pediatric patient undergoing craniospinal irradiation. The organ equivalent doses and effective dose from stray radiation were estimated for a 30.6-Gy treatment using Monte Carlo simulations of a passive scattering treatment unit and a patient-specific voxelized anatomy. The treatment plan was based on computed tomography images of...

  9. MO-G-18A-01: Radiation Dose Reducing Strategies in CT, Fluoroscopy and Radiography

    International Nuclear Information System (INIS)

    Advances in medical x-ray imaging have provided significant benefits to patient care. According to NCRP 160, there are more than 400 million x-ray procedures performed annually in the United States alone that contributes to nearly half of all the radiation exposure to the US population. Similar growth trends in medical x-ray imaging are observed worldwide. Apparent increase in number of medical x-ray imaging procedures, new protocols and the associated radiation dose and risk has drawn considerable attention. This has led to a number of technological innovations such as tube current modulation, iterative reconstruction algorithms, dose alerts, dose displays, flat panel digital detectors, high efficient digital detectors, storage phosphor radiography, variable filters, etc. that are enabling users to acquire medical x-ray images at a much lower radiation dose. Along with these, there are number of radiation dose optimization strategies that users can adapt to effectively lower radiation dose in medical x-ray procedures. The main objectives of this SAM course are to provide information and how to implement the various radiation dose optimization strategies in CT, Fluoroscopy and Radiography. Learning Objectives: To update impact of technological advances on dose optimization in medical imaging. To identify radiation optimization strategies in computed tomography. To describe strategies for configuring fluoroscopic equipment that yields optimal images at reasonable radiation dose. To assess ways to configure digital radiography systems and recommend ways to improve image quality at optimal dose

  10. Low dose gamma radiation on maize seed and its effect on plant growth and yield

    International Nuclear Information System (INIS)

    Seed or plant treatment with ionizing radiations, at certain doses can promote an increase and/or germination acceleration, greater plant development, an agricultural production increase, etc. Radiation doses used to obtain these stimuli do not provoke alteration on the genetic patrimony, because generally the dose level is very low. Low doses of gamma radiation have been reported to induce useful effects in rice, wheat, corn, tomato, radish, etc. which resulted in improved germination and higher yields. The present work is aimed to examine the effects of 60Co gamma radiation on maize seeds, on its development and crop production

  11. Estimation of radiation doses from 137Cs to frogs in a wetland ecosystem

    International Nuclear Information System (INIS)

    Currently, there is no established methodology to estimate radiation doses to non-human biota. Therefore, in this study, various dose models were used to estimate radiation doses to moor frogs (Rana arvalis) in a wetland ecosystem contaminated with 137Cs. External dose estimations were based on activity concentrations of 137Cs in soil and water, considering changes in habitat over a life-cycle. Internal doses were calculated from the activity concentrations of 137Cs measured in moor frogs. Depending on the dose model used, the results varied substantially. External dose rates ranged from 21 to 160 mGy/y, and internal dose rates varied between 1 and 14 mGy/y. Maximum total dose rates to frogs were below the expected safe level for terrestrial populations, but close to the suggested critical dose rate for amphibians. The results show that realistic assumptions in dose models are particularly important at high levels of contamination

  12. Analysis of occupational doses of workers on the dose registry of the Federal Radiation Protection Service in 2000 and 2001

    International Nuclear Information System (INIS)

    In 2000 and 2001 about 279 and 221 radiation workers, respectively, were monitored by the Federal Radiation Protection Service, University of Ibadan, in Nigeria. The distribution of the occupational doses shows that the majority of workers received doses below 4 mSv in each of the two years. The radiation workers in the two years are classified into two occupational categories: medicine and industry. The mean annual effective doses, collective doses and the collective dose distribution ratios for workers in each category and the entire monitored workers were calculated. The mean annual effective doses were compared with their corresponding worldwide values quoted by UNSCEAR. In each of the two years, a few workers in industry received doses higher than 50 mSv. The collective dose distribution ratio was found to be about 0.49, which is very close to the highest value of 0.5 in the range of values considered by UNSCEAR as normal for this parameter. This suggests that extra measures have to be taken, particularly in industry, to ensure that the proportion of workers at risk does not go outside this normal range. The occupational doses were also modelled by both the log-normal and Weibull distributions. Both distributions were found to describe the data in almost the same way. (author)

  13. TU-C-18A-01: Models of Risk From Low-Dose Radiation Exposures: What Does the Evidence Say?

    International Nuclear Information System (INIS)

    At dose levels of (approximately) 500 mSv or more, increased cancer incidence and mortality have been clearly demonstrated. However, at the low doses of radiation used in medical imaging, the relationship between dose and cancer risk is not well established. As such, assumptions about the shape of the dose-response curve are made. These assumptions, or risk models, are used to estimate potential long term effects. Common models include 1) the linear non-threshold (LNT) model, 2) threshold models with either a linear or curvilinear dose response above the