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Sample records for radiation risk estimates

  1. Relating space radiation environments to risk estimates

    NASA Technical Reports Server (NTRS)

    Curtis, Stanley B.

    1993-01-01

    A number of considerations must go into the process of determining the risk of deleterious effects of space radiation to travelers. Among them are (1) determination of the components of the radiation environment (particle species, fluxes and energy spectra) which will encounter, (2) determination of the effects of shielding provided by the spacecraft and the bodies of the travelers which modify the incident particle spectra and mix of particles, and (3) determination of relevant biological effects of the radiation in the organs of interest. The latter can then lead to an estimation of risk from a given space scenario. Clearly, the process spans many scientific disciplines from solar and cosmic ray physics to radiation transport theeory to the multistage problem of the induction by radiation of initial lesions in living material and their evolution via physical, chemical, and biological processes at the molecular, cellular, and tissue levels to produce the end point of importance.

  2. Estimation of health risks from radiation exposures

    SciTech Connect

    Randolph, M.L.

    1983-08-01

    An informal presentation is given of the cancer and genetic risks from exposures to ionizing radiations. The risks from plausible radiation exposures are shown to be comparable to other commonly encountered risks.

  3. Relating space radiation environments to risk estimates

    SciTech Connect

    Curtis, S.B.

    1991-10-01

    This lecture will provide a bridge from the physical energy or LET spectra as might be calculated in an organ to the risk of carcinogenesis, a particular concern for extended missions to the moon or beyond to Mars. Topics covered will include (1) LET spectra expected from galactic cosmic rays, (2) probabilities that individual cell nuclei in the body will be hit by heavy galactic cosmic ray particles, (3) the conventional methods of calculating risks from a mixed environment of high and low LET radiation, (4) an alternate method which provides certain advantages using fluence-related risk coefficients (risk cross sections), and (5) directions for future research and development of these ideas.

  4. Estimating radiation risk induced by CT screening for Korean population

    NASA Astrophysics Data System (ADS)

    Yang, Won Seok; Yang, Hye Jeong; Min, Byung In

    2017-02-01

    The purposes of this study are to estimate the radiation risks induced by chest/abdomen computed tomography (CT) screening for healthcare and to determine the cancer risk level of the Korean population compared to other populations. We used an ImPACT CT Patient Dosimetry Calculator to compute the organ effective dose induced by CT screening (chest, low-dose chest, abdomen/pelvis, and chest/abdomen/pelvis CT). A risk model was applied using principles based on the BEIR VII Report in order to estimate the lifetime attributable risk (LAR) using the Korean Life Table 2010. In addition, several countries including Hong Kong, the United States (U.S.), and the United Kingdom, were selected for comparison. Herein, each population exposed radiation dose of 100 mSv was classified according to country, gender and age. For each CT screening the total organ effective dose calculated by ImPACT was 6.2, 1.5, 5.2 and 11.4 mSv, respectively. In the case of Korean female LAR, it was similar to Hong Kong female but lower than those of U.S. and U.K. females, except for those in their twenties. The LAR of Korean males was the highest for all types of CT screening. However, the difference of the risk level was negligible because of the quite low value.

  5. Risk estimation based on chromosomal aberrations induced by radiation

    NASA Technical Reports Server (NTRS)

    Durante, M.; Bonassi, S.; George, K.; Cucinotta, F. A.

    2001-01-01

    The presence of a causal association between the frequency of chromosomal aberrations in peripheral blood lymphocytes and the risk of cancer has been substantiated recently by epidemiological studies. Cytogenetic analyses of crew members of the Mir Space Station have shown that a significant increase in the frequency of chromosomal aberrations can be detected after flight, and that such an increase is likely to be attributed to the radiation exposure. The risk of cancer can be estimated directly from the yields of chromosomal aberrations, taking into account some aspects of individual susceptibility and other factors unrelated to radiation. However, the use of an appropriate technique for the collection and analysis of chromosomes and the choice of the structural aberrations to be measured are crucial in providing sound results. Based on the fraction of aberrant lymphocytes detected before and after flight, the relative risk after a long-term Mir mission is estimated to be about 1.2-1.3. The new technique of mFISH can provide useful insights into the quantification of risk on an individual basis.

  6. Cancer risk estimation caused by radiation exposure during endovascular procedure

    NASA Astrophysics Data System (ADS)

    Kang, Y. H.; Cho, J. H.; Yun, W. S.; Park, K. H.; Kim, H. G.; Kwon, S. M.

    2014-05-01

    The objective of this study was to identify the radiation exposure dose of patients, as well as staff caused by fluoroscopy for C-arm-assisted vascular surgical operation and to estimate carcinogenic risk due to such exposure dose. The study was conducted in 71 patients (53 men and 18 women) who had undergone vascular surgical intervention at the division of vascular surgery in the University Hospital from November of 2011 to April of 2012. It had used a mobile C-arm device and calculated the radiation exposure dose of patient (dose-area product, DAP). Effective dose was measured by attaching optically stimulated luminescence on the radiation protectors of staff who participates in the surgery to measure the radiation exposure dose of staff during the vascular surgical operation. From the study results, DAP value of patients was 308.7 Gy cm2 in average, and the maximum value was 3085 Gy cm2. When converted to the effective dose, the resulted mean was 6.2 m Gy and the maximum effective dose was 61.7 milliSievert (mSv). The effective dose of staff was 3.85 mSv; while the radiation technician was 1.04 mSv, the nurse was 1.31 mSv. All cancer incidences of operator are corresponding to 2355 persons per 100,000 persons, which deemed 1 of 42 persons is likely to have all cancer incidences. In conclusion, the vascular surgeons should keep the radiation protection for patient, staff, and all participants in the intervention in mind as supervisor of fluoroscopy while trying to understand the effects by radiation by themselves to prevent invisible danger during the intervention and to minimize the harm.

  7. BACKGROUND RADIATION MEASUREMENTS AND CANCER RISK ESTIMATES FOR SEBINKARAHISAR, TURKEY.

    PubMed

    Kurnaz, Asli

    2013-07-19

    This paper presents the measurement results of environmental radioactivity levels for Şebinkarahisar district (uranium-thorium area), Giresun, Turkey. The radioactivity concentrations of (238)U, (232)Th, (40)K and the fission product (137)Cs in soil samples collected from 73 regions from the surroundings of the study area were determined. In situ measurements of the gamma dose rate in air were performed in the same 73 locations where the soil samples were collected using a portable NaI detector. Also the mean radioactivity concentrations of (238)U, (232)Th and (40)K in rock samples collected from 50 regions were determined. The mean estimated cancer risk value was found. The seasonal variations of the indoor radon activity concentrations were determined in the 30 dwellings in the study area. In addition, the mean gross alpha, gross beta and radon activities in tap water samples were determined in the same 30 dwellings. The excess lifetime cancer risk was calculated using the risk factors of International Commission on Radiological Protection and Biological Effects of Ionizing Radiation. Radiological maps of the Şebinkarahisar region were composed using the results obtained from this study.

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

    NASA Technical Reports Server (NTRS)

    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

  9. Probabilistic methodology for estimating radiation-induced cancer risk

    SciTech Connect

    Dunning, D.E. Jr.; Leggett, R.W.; Williams, L.R.

    1981-01-01

    The RICRAC computer code was developed at Oak Ridge National Laboratory to provide a versatile and convenient methodology for radiation risk assessment. The code allows as input essentially any dose pattern commonly encountered in risk assessments for either acute or chronic exposures, and it includes consideration of the age structure of the exposed population. Results produced by the analysis include the probability of one or more radiation-induced cancer deaths in a specified population, expected numbers of deaths, and expected years of life lost as a result of premature fatalities. These calculatons include consideration of competing risks of death from all other causes. The program also generates a probability frequency distribution of the expected number of cancers in any specified cohort resulting from a given radiation dose. The methods may be applied to any specified population and dose scenario.

  10. An update on standards for radiation in the environment and associated estimates of risk

    SciTech Connect

    Kocher, D.C.

    1989-06-21

    This presentation reviews current and proposed standards, recommendations, and guidances for limiting routine radiation exposures of the public, and estimates the risk corresponding to standards, recommendations, and guidances. These estimates provide a common basis for comparing different criteria for limiting public exposures to radiation, as well as hazardous chemicals.

  11. Space Radiation Heart Disease Risk Estimates for Lunar and Mars Missions

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Chappell, Lori; Kim, Myung-Hee

    2010-01-01

    The NASA Space Radiation Program performs research on the risks of late effects from space radiation for cancer, neurological disorders, cataracts, and heart disease. For mortality risks, an aggregate over all risks should be considered as well as projection of the life loss per radiation induced death. We report on a triple detriment life-table approach to combine cancer and heart disease risks. Epidemiology results show extensive heterogeneity between populations for distinct components of the overall heart disease risks including hypertension, ischaemic heart disease, stroke, and cerebrovascular diseases. We report on an update to our previous heart disease estimates for Heart disease (ICD9 390-429) and Stroke (ICD9 430-438), and other sub-groups using recent meta-analysis results for various exposed radiation cohorts to low LET radiation. Results for multiplicative and additive risk transfer models are considered using baseline rates for US males and female. Uncertainty analysis indicated heart mortality risks as low as zero, assuming a threshold dose for deterministic effects, and projections approaching one-third of the overall cancer risk. Medan life-loss per death estimates were significantly less than that of solid cancer and leukemias. Critical research questions to improve risks estimates for heart disease are distinctions in mechanisms at high doses (>2 Gy) and low to moderate doses (<2 Gy), and data and basic understanding of radiation doserate and quality effects, and individual sensitivity.

  12. Estimate of Space Radiation-Induced Cancer Risks for International Space Station Orbits

    NASA Technical Reports Server (NTRS)

    Wu, Honglu; Atwell, William; Cucinotta, Francis A.; Yang, Chui-hsu

    1996-01-01

    Excess cancer risks from exposures to space radiation are estimated for various orbits of the International Space Station (ISS). Organ exposures are computed with the transport codes, BRYNTRN and HZETRN, and the computerized anatomical male and computerized anatomical female models. Cancer risk coefficients in the National Council on Radiation Protection and Measurements report No. 98 are used to generate lifetime excess cancer incidence and cancer mortality after a one-month mission to ISS. The generated data are tabulated to serve as a quick reference for assessment of radiation risk to astronauts on ISS missions.

  13. Estimate of Space Radiation-Induced Cancer Risks for International Space Station Orbits

    SciTech Connect

    Wu, H.; Atwell, W.; Cucinotta, F.A.; Yang, C.

    1996-03-01

    Excess cancer risks from exposures to space radiation are estimated for various orbits of the International Space Station (ISS). Organ exposures are computed with the transport codes, BRYNTRN and HZETRN, and the computerized anatomical male and computerized anatomical female models. Cancer risk coefficients in the National Council on Radiation Protection and Measurements report No. 98 are used to generate lifetime excess cancer incidence and cancer mortality after a one-month mission to ISS. The generated data are tabulated to serve as a quick reference for assessment of radiation risk to astronauts on ISS missions.

  14. Genome-based, mechanism-driven computational modeling of risks of ionizing radiation: The next frontier in genetic risk estimation?

    PubMed

    Sankaranarayanan, K; Nikjoo, H

    2015-01-01

    Research activity in the field of estimation of genetic risks of ionizing radiation to human populations started in the late 1940s and now appears to be passing through a plateau phase. This paper provides a background to the concepts, findings and methods of risk estimation that guided the field through the period of its growth to the beginning of the 21st century. It draws attention to several key facts: (a) thus far, genetic risk estimates have been made indirectly using mutation data collected in mouse radiation studies; (b) important uncertainties and unsolved problems remain, one notable example being that we still do not know the sensitivity of human female germ cells to radiation-induced mutations; and (c) the concept that dominated the field thus far, namely, that radiation exposures to germ cells can result in single gene diseases in the descendants of those exposed has been replaced by the concept that radiation exposure can cause DNA deletions, often involving more than one gene. Genetic risk estimation now encompasses work devoted to studies on DNA deletions induced in human germ cells, their expected frequencies, and phenotypes and associated clinical consequences in the progeny. We argue that the time is ripe to embark on a human genome-based, mechanism-driven, computational modeling of genetic risks of ionizing radiation, and we present a provisional framework for catalyzing research in the field in the 21st century.

  15. Problems and solutions in the estimation of genetic risks from radiation and chemicals

    SciTech Connect

    Russell, W. L.

    1980-01-01

    Extensive investigations with mice on the effects of various physical and biological factors, such as dose rate, sex and cell stage, on radiation-induced mutation have provided an evaluation of the genetics hazards of radiation in man. The mutational results obtained in both sexes with progressive lowering of the radiation dose rate have permitted estimation of the mutation frequency expected under the low-level radiation conditions of most human exposure. Supplementing the studies on mutation frequency are investigations on the phenotypic effects of mutations in mice, particularly anatomical disorders of the skeleton, which allow an estimation of the degree of human handicap associated with the occurrence of parallel defects in man. Estimation of the genetic risk from chemical mutagens is much more difficult, and the research is much less advanced. Results on transmitted mutations in mice indicate a poor correlation with mutation induction in non-mammalian organisms.

  16. Risk estimators for radiation-induced bone marrow syndrome lethality in humans

    SciTech Connect

    Scott, B.R.; Hahn, F.F.; McClellan, R.O.; Seiler, F.A.

    1988-09-01

    This manuscript provides risk estimators for acute lethality from radiation-induced injury to the bone marrow of humans after uniform total-body exposure to low linear energy transfer (LET) radiation. The risk estimators are needed for nuclear disaster risk assessment. The approach used is based on the dose X, in units of D50 (i.e., the dose required for 50% lethality). Using animal data, it is demonstrated that the use of dose in units of D50 eliminates most of the variability associated with mammalian species, type of low-LET radiation, and low-LET dose rate. Animal data are used to determine the shape of the dose-effect curve for marrow-syndrome lethality in man and to develop a functional relationship for the dependence of the D50 on dose rate. The functional relationship is used, along with the Weibull model, to develop acute lethality risk estimators for complex temporal patterns of continuous exposure to low-LET radiation. Animal data are used to test model predictions.

  17. Studies on the Hiroshima and Nagasaki survivors, and their use in estimating radiation risks.

    PubMed

    Muirhead, C R

    2003-01-01

    Epidemiological studies of the survivors of the atomic bombings of Hiroshima and Nagasaki have been conducted over many years. These studies have examined, inter alia, mortality and cancer incidence among the survivors. This paper summarises the form of the studies undertaken, outlines the main findings and describes how these results can be used in deriving estimates of radiation risks. In doing so, some areas of uncertainty and open issues are highlighted, such as the magnitude of lifetime cancer risks and the evidence for raised risks of non-cancer diseases at low doses. Continued follow-up of the survivors will be important in shedding further light on these issues.

  18. Uncertainties in estimating health risks associated with exposure to ionising radiation.

    PubMed

    Preston, R Julian; Boice, John D; Brill, A Bertrand; Chakraborty, Ranajit; Conolly, Rory; Hoffman, F Owen; Hornung, Richard W; Kocher, David C; Land, Charles E; Shore, Roy E; Woloschak, Gayle E

    2013-09-01

    The information for the present discussion on the uncertainties associated with estimation of radiation risks and probability of disease causation was assembled for the recently published NCRP Report No. 171 on this topic. This memorandum provides a timely overview of the topic, given that quantitative uncertainty analysis is the state of the art in health risk assessment and given its potential importance to developments in radiation protection. Over the past decade the increasing volume of epidemiology data and the supporting radiobiology findings have aided in the reduction of uncertainty in the risk estimates derived. However, it is equally apparent that there remain significant uncertainties related to dose assessment, low dose and low dose-rate extrapolation approaches (e.g. the selection of an appropriate dose and dose-rate effectiveness factor), the biological effectiveness where considerations of the health effects of high-LET and lower-energy low-LET radiations are required and the transfer of risks from a population for which health effects data are available to one for which such data are not available. The impact of radiation on human health has focused in recent years on cancer, although there has been a decided increase in the data for noncancer effects together with more reliable estimates of the risk following radiation exposure, even at relatively low doses (notably for cataracts and cardiovascular disease). New approaches for the estimation of hereditary risk have been developed with the use of human data whenever feasible, although the current estimates of heritable radiation effects still are based on mouse data because of an absence of effects in human studies. Uncertainties associated with estimation of these different types of health effects are discussed in a qualitative and semi-quantitative manner as appropriate. The way forward would seem to require additional epidemiological studies, especially studies of low dose and low dose

  19. Uncertainties in Estimates of the Risks of Late Effects from Space Radiation

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Schimmerling, W.; Wilson, J. W.; Peterson, L. E.; Saganti, P.; Dicelli, J. F.

    2002-01-01

    The health risks faced by astronauts from space radiation include cancer, cataracts, hereditary effects, and non-cancer morbidity and mortality risks related to the diseases of the old age. Methods used to project risks in low-Earth orbit are of questionable merit for exploration missions because of the limited radiobiology data and knowledge of galactic cosmic ray (GCR) heavy ions, which causes estimates of the risk of late effects to be highly uncertain. Risk projections involve a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Within the linear-additivity model, we use Monte-Carlo sampling from subjective uncertainty distributions in each factor to obtain a Maximum Likelihood estimate of the overall uncertainty in risk projections. The resulting methodology is applied to several human space exploration mission scenarios including ISS, lunar station, deep space outpost, and Mar's missions of duration of 360, 660, and 1000 days. The major results are the quantification of the uncertainties in current risk estimates, the identification of factors that dominate risk projection uncertainties, and the development of a method to quantify candidate approaches to reduce uncertainties or mitigate risks. The large uncertainties in GCR risk projections lead to probability distributions of risk that mask any potential risk reduction using the "optimization" of shielding materials or configurations. In contrast, the design of shielding optimization approaches for solar particle events and trapped protons can be made at this time, and promising technologies can be shown to have merit using our approach. The methods used also make it possible to express risk management objectives in terms of quantitative objective's, i.e., the number of days in space without exceeding a given risk level within well defined confidence limits.

  20. Uncertainties in estimates of the risks of late effects from space radiation

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Schimmerling, W.; Wilson, J. W.; Peterson, L. E.; Saganti, P. B.; Dicello, J. F.

    2004-01-01

    Methods used to project risks in low-Earth orbit are of questionable merit for exploration missions because of the limited radiobiology data and knowledge of galactic cosmic ray (GCR) heavy ions, which causes estimates of the risk of late effects to be highly uncertain. Risk projections involve a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Using the linear-additivity model for radiation risks, we use Monte-Carlo sampling from subjective uncertainty distributions in each factor to obtain an estimate of the overall uncertainty in risk projections. The resulting methodology is applied to several human space exploration mission scenarios including a deep space outpost and Mars missions of duration of 360, 660, and 1000 days. The major results are the quantification of the uncertainties in current risk estimates, the identification of factors that dominate risk projection uncertainties, and the development of a method to quantify candidate approaches to reduce uncertainties or mitigate risks. The large uncertainties in GCR risk projections lead to probability distributions of risk that mask any potential risk reduction using the "optimization" of shielding materials or configurations. In contrast, the design of shielding optimization approaches for solar particle events and trapped protons can be made at this time and promising technologies can be shown to have merit using our approach. The methods used also make it possible to express risk management objectives in terms of quantitative metrics, e.g., the number of days in space without exceeding a given risk level within well-defined confidence limits. Published by Elsevier Ltd on behalf of COSPAR.

  1. Estimates of Radiation Doses and Cancer Risk from Food Intake in Korea

    PubMed Central

    2016-01-01

    The aim of this study was to estimate internal radiation doses and lifetime cancer risk from food ingestion. Radiation doses from food intake were calculated using the Korea National Health and Nutrition Examination Survey and the measured radioactivity of 134Cs, 137Cs, and 131I from the Ministry of Food and Drug Safety in Korea. Total number of measured data was 8,496 (3,643 for agricultural products, 644 for livestock products, 43 for milk products, 3,193 for marine products, and 973 for processed food). Cancer risk was calculated by multiplying the estimated committed effective dose and the detriment adjusted nominal risk coefficients recommended by the International Commission on Radiation Protection. The lifetime committed effective doses from the daily diet are ranged 2.957-3.710 mSv. Excess lifetime cancer risks are 14.4-18.1, 0.4-0.5, and 1.8-2.3 per 100,000 for all solid cancers combined, thyroid cancer, and leukemia, respectively. PMID:26770031

  2. Estimates of Radiation Doses and Cancer Risk from Food Intake in Korea.

    PubMed

    Moon, Eun-Kyeong; Ha, Wi-Ho; Seo, Songwon; Jin, Young Woo; Jeong, Kyu Hwan; Yoon, Hae-Jung; Kim, Hyoung-Soo; Hwang, Myung-Sil; Choi, Hoon; Lee, Won Jin

    2016-01-01

    The aim of this study was to estimate internal radiation doses and lifetime cancer risk from food ingestion. Radiation doses from food intake were calculated using the Korea National Health and Nutrition Examination Survey and the measured radioactivity of (134)Cs, (137)Cs, and (131)I from the Ministry of Food and Drug Safety in Korea. Total number of measured data was 8,496 (3,643 for agricultural products, 644 for livestock products, 43 for milk products, 3,193 for marine products, and 973 for processed food). Cancer risk was calculated by multiplying the estimated committed effective dose and the detriment adjusted nominal risk coefficients recommended by the International Commission on Radiation Protection. The lifetime committed effective doses from the daily diet are ranged 2.957-3.710 mSv. Excess lifetime cancer risks are 14.4-18.1, 0.4-0.5, and 1.8-2.3 per 100,000 for all solid cancers combined, thyroid cancer, and leukemia, respectively.

  3. Estimating the risks of cancer mortality and genetic defects resulting from exposures to low levels of ionizing radiation

    SciTech Connect

    Buhl, T.E.; Hansen, W.R.

    1984-05-01

    Estimators for calculating the risk of cancer and genetic disorders induced by exposure to ionizing radiation have been recommended by the US National Academy of Sciences Committee on the Biological Effects of Ionizing Radiations, the UN Scientific Committee on the Effects of Atomic Radiation, and the International Committee on Radiological Protection. These groups have also considered the risks of somatic effects other than cancer. The US National Council on Radiation Protection and Measurements has discussed risk estimate procedures for radiation-induced health effects. The recommendations of these national and international advisory committees are summarized and compared in this report. Based on this review, two procedures for risk estimation are presented for use in radiological assessments performed by the US Department of Energy under the National Environmental Policy Act of 1969 (NEPA). In the first procedure, age- and sex-averaged risk estimators calculated with US average demographic statistics would be used with estimates of radiation dose to calculate the projected risk of cancer and genetic disorders that would result from the operation being reviewed under NEPA. If more site-specific risk estimators are needed, and the demographic information is available, a second procedure is described that would involve direct calculation of the risk estimators using recommended risk-rate factors. The computer program REPCAL has been written to perform this calculation and is described in this report. 25 references, 16 tables.

  4. Estimation of Effective Doses for Radiation Cancer Risks on ISS, Lunar, and Mars Missions with Space Radiation Measurement

    NASA Technical Reports Server (NTRS)

    Kim, M.Y.; Cucinotta, F.A.

    2005-01-01

    Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. The Phantom Torso Experiment (PTE) of NASA s Operational Radiation Protection Program has provided the actual flight measurements of active and passive dosimeters which were placed throughout the phantom on STS-91 mission for 10 days and on ISS Increment 2 mission. For the PTE, the variation in organ doses, which is resulted by the absorption and the changes in radiation quality with tissue shielding, was considered by measuring doses at many tissue sites and at several critical body organs including brain, colon, heart, stomach, thyroid, and skins. These measurements have been compared with the organ dose calculations obtained from the transport models. Active TEPC measurements of lineal energy spectra at the surface of the PTE also provided the direct comparison of galactic cosmic ray (GCR) or trapped proton dose and dose equivalent. It is shown that orienting the phantom body as actual in ISS is needed for the direct comparison of the transport models to the ISS data. One of the most important observations for organ dose equivalent of effective dose estimates on ISS is the fractional contribution from trapped protons and GCR. We show that for most organs over 80% is from GCR. The improved estimation of effective doses for radiation cancer risks will be made with the resultant tissue weighting factors and the modified codes.

  5. Cancer risk estimates from radiation therapy for heterotopic ossification prophylaxis after total hip arthroplasty

    SciTech Connect

    Mazonakis, Michalis; Berris, Theoharris; Damilakis, John; Lyraraki, Efrossyni

    2013-10-15

    Purpose: Heterotopic ossification (HO) is a frequent complication following total hip arthroplasty. This study was conducted to calculate the radiation dose to organs-at-risk and estimate the probability of cancer induction from radiotherapy for HO prophylaxis.Methods: Hip irradiation for HO with a 6 MV photon beam was simulated with the aid of a Monte Carlo model. A realistic humanoid phantom representing an average adult patient was implemented in Monte Carlo environment for dosimetric calculations. The average out-of-field radiation dose to stomach, liver, lung, prostate, bladder, thyroid, breast, uterus, and ovary was calculated. The organ-equivalent-dose to colon, that was partly included within the treatment field, was also determined. Organ dose calculations were carried out using three different field sizes. The dependence of organ doses upon the block insertion into primary beam for shielding colon and prosthesis was investigated. The lifetime attributable risk for cancer development was estimated using organ, age, and gender-specific risk coefficients.Results: For a typical target dose of 7 Gy, organ doses varied from 1.0 to 741.1 mGy by the field dimensions and organ location relative to the field edge. Blocked field irradiations resulted in a dose range of 1.4–146.3 mGy. The most probable detriment from open field treatment of male patients was colon cancer with a high risk of 564.3 × 10{sup −5} to 837.4 × 10{sup −5} depending upon the organ dose magnitude and the patient's age. The corresponding colon cancer risk for female patients was (372.2–541.0) × 10{sup −5}. The probability of bladder cancer development was more than 113.7 × 10{sup −5} and 110.3 × 10{sup −5} for males and females, respectively. The cancer risk range to other individual organs was reduced to (0.003–68.5) × 10{sup −5}.Conclusions: The risk for cancer induction from radiation therapy for HO prophylaxis after total hip arthroplasty varies considerably by the

  6. ADVISORY ON UPDATED METHODOLOGY FOR ESTIMATING CANCER RISKS FROM EXPOSURE TO IONIZING RADIATION

    EPA Science Inventory

    The National Academy of Sciences (NAS) published the Biological Effects of Ionizing Radiation (BEIR) committee's report (BEIR VII) on risks from ionizing radiation exposures in 2006. The Committee analyzed the most recent epidemiology from the important exposed cohorts and factor...

  7. Improved Radiation Dosimetry/Risk Estimates to Facilitate Environmental Management of Plutonium-Contaminated Sites

    SciTech Connect

    Scott, Bobby R.; Tokarskaya, Zoya B.; Zhuntova, Galina V.; Osovets, Sergey V.; Syrchikov, Victor A., Belyaeva, Zinaida D.

    2007-12-14

    This report summarizes 4 years of research achievements in this Office of Science (BER), U.S. Department of Energy (DOE) project. The research described was conducted by scientists and supporting staff at Lovelace Respiratory Research Institute (LRRI)/Lovelace Biomedical and Environmental Research Institute (LBERI) and the Southern Urals Biophysics Institute (SUBI). All project objectives and goals were achieved. A major focus was on obtaining improved cancer risk estimates for exposure via inhalation to plutonium (Pu) isotopes in the workplace (DOE radiation workers) and environment (public exposures to Pu-contaminated soil). A major finding was that low doses and dose rates of gamma rays can significantly suppress cancer induction by alpha radiation from inhaled Pu isotopes. The suppression relates to stimulation of the body's natural defenses, including immunity against cancer cells and selective apoptosis which removes precancerous and other aberrant cells.

  8. Estimating Radiogenic Cancer Risks

    EPA Pesticide Factsheets

    This document presents a revised methodology for EPA's estimation of cancer risks due to low-LET radiation exposures developed in light of information that has become available, especially new information on the Japanese atomic bomb survivors.

  9. Radiation Dose and Cancer Risk Estimates in 16-Slice Computed Tomography Coronary Angiography

    PubMed Central

    Einstein, Andrew J.; Sanz, Javier; Dellegrottaglie, Santo; Milite, Margherita; Sirol, Marc; Henzlova, Milena; Rajagopalan, Sanjay

    2008-01-01

    Background Recent advances have led to a rapid increase in the number of computed tomography coronary angiography (CTCA) studies performed. While several studies have reported effective dose (E), there is no data available on cancer risk for current CTCA protocols. Methods and Results E and organ doses were estimated, using scanner-derived parameters and Monte Carlo methods, for 50 patients having 16-slice CTCA performed for clinical indications. Lifetime attributable risks (LARs) were estimated with models developed in the National Academies’ Biological Effects of Ionizing Radiation VII report. E of a complete CTCA averaged 9.5 mSv, while that of a complete study, including calcium scoring when indicated, averaged 11.7 mSv. Calcium scoring increased E by 25%, while tube current modulation reduced it by 34% and was more effective at lower heart rates. Organ doses were highest to the lungs and female breast. LAR of cancer incidence from CTCA averaged approximately 1 in 1600, but varied widely between patients, being highest in younger women. For all patients, the greatest risk was from lung cancer. Conclusions CTCA is associated with non-negligible risk of malignancy. Doses can be reduced by careful attention to scanning protocol. PMID:18371595

  10. Radiation passport: an iPhone and iPod touch application to track radiation dose and estimate associated cancer risks.

    PubMed

    Baerlocher, Mark Otto; Talanow, Roland; Baerlocher, Adrian F

    2010-04-01

    The rapid increase in the use of radiology and related exams and procedures has led to a concomitant increase in associated radiation risk. An application for the iPhone and iPod Touch called 'Radiation Passport' is described, which provides radiation dose estimates and associated cancer risks (non fatal and fatal) and serves as a method by which to track an individual's cumulative exposure.

  11. Patients with Testicular Cancer Undergoing CT Surveillance Demonstrate a Pitfall of Radiation-induced Cancer Risk Estimates: The Timing Paradox

    PubMed Central

    Eisenberg, Jonathan D.; Lee, Richard J.; Gilmore, Michael E.; Turan, Ekin A.; Singh, Sarabjeet; Kalra, Mannudeep K.; Liu, Bob; Kong, Chung Yin; Gazelle, G. Scott

    2013-01-01

    Purpose: To demonstrate a limitation of lifetime radiation-induced cancer risk metrics in the setting of testicular cancer surveillance—in particular, their failure to capture the delayed timing of radiation-induced cancers over the course of a patient’s lifetime. Materials and Methods: Institutional review board approval was obtained for the use of computed tomographic (CT) dosimetry data in this study. Informed consent was waived. This study was HIPAA compliant. A Markov model was developed to project outcomes in patients with testicular cancer who were undergoing CT surveillance in the decade after orchiectomy. To quantify effects of early versus delayed risks, life expectancy losses and lifetime mortality risks due to testicular cancer were compared with life expectancy losses and lifetime mortality risks due to radiation-induced cancers from CT. Projections of life expectancy loss, unlike lifetime risk estimates, account for the timing of risks over the course of a lifetime, which enabled evaluation of the described limitation of lifetime risk estimates. Markov chain Monte Carlo methods were used to estimate the uncertainty of the results. Results: As an example of evidence yielded, 33-year-old men with stage I seminoma who were undergoing CT surveillance were projected to incur a slightly higher lifetime mortality risk from testicular cancer (598 per 100 000; 95% uncertainty interval [UI]: 302, 894) than from radiation-induced cancers (505 per 100 000; 95% UI: 280, 730). However, life expectancy loss attributable to testicular cancer (83 days; 95% UI: 42, 124) was more than three times greater than life expectancy loss attributable to radiation-induced cancers (24 days; 95% UI: 13, 35). Trends were consistent across modeled scenarios. Conclusion: Lifetime radiation risk estimates, when used for decision making, may overemphasize radiation-induced cancer risks relative to short-term health risks. © RSNA, 2012 Supplemental material: http

  12. The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry: estimates of radiation-related cancer risks.

    PubMed

    Cardis, E; Vrijheid, M; Blettner, M; Gilbert, E; Hakama, M; Hill, C; Howe, G; Kaldor, J; Muirhead, C R; Schubauer-Berigan, M; Yoshimura, T; Bermann, F; Cowper, G; Fix, J; Hacker, C; Heinmiller, B; Marshall, M; Thierry-Chef, I; Utterback, D; Ahn, Y-O; Amoros, E; Ashmore, P; Auvinen, A; Bae, J-M; Bernar, J; Biau, A; Combalot, E; Deboodt, P; Diez Sacristan, A; Eklöf, M; Engels, H; Engholm, G; Gulis, G; Habib, R R; Holan, K; Hyvonen, H; Kerekes, A; Kurtinaitis, J; Malker, H; Martuzzi, M; Mastauskas, A; Monnet, A; Moser, M; Pearce, M S; Richardson, D B; Rodriguez-Artalejo, F; Rogel, A; Tardy, H; Telle-Lamberton, M; Turai, I; Usel, M; Veress, K

    2007-04-01

    A 15-Country collaborative cohort study was conducted to provide direct estimates of cancer risk following protracted low doses of ionizing radiation. Analyses included 407,391 nuclear industry workers monitored individually for external radiation and 5.2 million person-years of follow-up. A significant association was seen between radiation dose and all-cause mortality [excess relative risk (ERR) 0.42 per Sv, 90% CI 0.07, 0.79; 18,993 deaths]. This was mainly attributable to a dose-related increase in all cancer mortality (ERR/Sv 0.97, 90% CI 0.28, 1.77; 5233 deaths). Among 31 specific types of malignancies studied, a significant association was found for lung cancer (ERR/Sv 1.86, 90% CI 0.49, 3.63; 1457 deaths) and a borderline significant (P = 0.06) association for multiple myeloma (ERR/Sv 6.15, 90% CI <0, 20.6; 83 deaths) and ill-defined and secondary cancers (ERR/Sv 1.96, 90% CI -0.26, 5.90; 328 deaths). Stratification on duration of employment had a large effect on the ERR/Sv, reflecting a strong healthy worker survivor effect in these cohorts. This is the largest analytical epidemiological study of the effects of low-dose protracted exposures to ionizing radiation to date. Further studies will be important to better assess the role of tobacco and other occupational exposures in our risk estimates.

  13. Patient-specific radiation dose and cancer risk estimation in CT: Part II. Application to patients

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P.

    2011-01-15

    Purpose: Current methods for estimating and reporting radiation dose from CT examinations are largely patient-generic; the body size and hence dose variation from patient to patient is not reflected. Furthermore, the current protocol designs rely on dose as a surrogate for the risk of cancer incidence, neglecting the strong dependence of risk on age and gender. The purpose of this study was to develop a method for estimating patient-specific radiation dose and cancer risk from CT examinations. Methods: The study included two patients (a 5-week-old female patient and a 12-year-old male patient), who underwent 64-slice CT examinations (LightSpeed VCT, GE Healthcare) of the chest, abdomen, and pelvis at our institution in 2006. For each patient, a nonuniform rational B-spine (NURBS) based full-body computer model was created based on the patient's clinical CT data. Large organs and structures inside the image volume were individually segmented and modeled. Other organs were created by transforming an existing adult male or female full-body computer model (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. A Monte Carlo program previously developed and validated for dose simulation on the LightSpeed VCT scanner was used to estimate patient-specific organ dose, from which effective dose and risks of cancer incidence were derived. Patient-specific organ dose and effective dose were compared with patient-generic CT dose quantities in current clinical use: the volume-weighted CT dose index (CTDI{sub vol}) and the effective dose derived from the dose-length product (DLP). Results: The effective dose for the CT examination of the newborn patient (5.7 mSv) was higher but comparable to that for the CT examination of the teenager patient (4.9 mSv) due to the size-based clinical CT protocols at our institution, which employ lower scan techniques for smaller

  14. Radiation risk estimation: Modelling approaches for “targeted” and “non-targeted” effects

    NASA Astrophysics Data System (ADS)

    Ballarini, Francesca; Alloni, Daniele; Facoetti, Angelica; Mairani, Andrea; Nano, Rosanna; Ottolenghi, Andrea

    The estimation of the risks from low doses of ionizing radiation - including heavy ions - is still a debated question. In particular, the action of heavy ions on biological targets needs further investigation. In this framework, we present a mechanistic model and a Monte Carlo simulation code for the induction of different types of chromosome aberrations. The model, previously validated for gamma rays and light ions, has recently started to be extended to heavy ions such as Iron and Carbon, which are of interest both for space radiation protection and for hadrontherapy. Preliminary results were found to be in agreement with experimental dose-response curves for aberration yields observed following heavy-ion irradiation of human lymphocytes treated with the Premature Chromosome Condensation technique. During the last 10 years, the "Linear No Threshold" hypothesis has been challenged by a large number of observations on the so-called "non-targeted effects" including bystander effect, which consists of the induction of cytogenetic damage in cells not directly traversed by radiation, most likely as a response to molecular messengers released by directly irradiated cells. Although it is now clear that cellular communication plays a fundamental role, our knowledge on the mechanisms underlying bystander effects is still poor, and would largely benefit from further investigations including theoretical models and simulation codes. In the present paper we will review different modelling approaches, including one that is being developed at the University of Pavia, focusing on the assumptions adopted by the various authors and on their implications in terms of low-dose radiation risk, as well as on the identification of "critical" parameters that can modulate the model outcomes.

  15. Biokinetic and dosimetric modelling in the estimation of radiation risks from internal emitters.

    PubMed

    Harrison, John

    2009-06-01

    The International Commission on Radiological Protection (ICRP) has developed biokinetic and dosimetric models that enable the calculation of organ and tissue doses for a wide range of radionuclides. These are used to calculate equivalent and effective dose coefficients (dose in Sv Bq(-1) intake), considering occupational and environmental exposures. Dose coefficients have also been given for a range of radiopharmaceuticals used in diagnostic medicine. Using equivalent and effective dose, exposures from external sources and from different radionuclides can be summed for comparison with dose limits, constraints and reference levels that relate to risks from whole-body radiation exposure. Risk estimates are derived largely from follow-up studies of the survivors of the atomic bombings at Hiroshima and Nagasaki in 1945. New dose coefficients will be required following the publication in 2007 of new ICRP recommendations. ICRP biokinetic and dosimetric models are subject to continuing review and improvement, although it is arguable that the degree of sophistication of some of the most recent models is greater than required for the calculation of effective dose to a reference person for the purposes of regulatory control. However, the models are also used in the calculation of best estimates of doses and risks to individuals, in epidemiological studies and to determine probability of cancer causation. Models are then adjusted to best fit the characteristics of the individuals and population under consideration. For example, doses resulting from massive discharges of strontium-90 and other radionuclides to the Techa River from the Russian Mayak plutonium plant in the early years of its operation are being estimated using models adapted to take account of measurements on local residents and other population-specific data. Best estimates of doses to haemopoietic bone marrow, in utero and postnatally, are being used in epidemiological studies of radiation-induced leukaemia

  16. Estimation of risk based on multiple events in radiation carcinogenesis of rat skin

    NASA Astrophysics Data System (ADS)

    Burns, F. J.; Jin, Y.; Garte, S. J.; Hosselet, S.

    1994-10-01

    In the multistage theory of carcinogenesis, cells progress to cancer through a series of discrete, irreversible, heritable genetic alterations or mutations. However data on radiation-induced cancer incidence in rat skin suggests that some part of an intermediate repairable alteration may occur. Data are presented on cancer induction in rat skin exposed to the following radiations: 1. an electron beam (LET = 0.34 keV/um, 2. a neon ion beam (LET = 25 keV/um and 3. an argon ion beam (LET = 125 keV/um. The latter 2 beams were generated by the Bevalac at the Lawrence Berkeley Laboratory, Berkeley, CA. About 6.0 cm2 of skin was irradiated per rat. The rats were observed every 6 weeks for at least 78 weeks and tumors were scored at first occurrence. Several histological types of cancer, including squamous and basal cell carcinomas, were induced. The cancer yield versus radiation dose was fitted by the quadratic equation (Y (D) = CLD + BD2), and the parameters C and B were estimated for each type of radiation. Analysis of the DNA from the electron-induced carcinomas indicated that K-ras and/or c-myc oncogenes were activated in all tumors tested, although only a small proportion of neon-induced tumors showed similar activation. In situ hybridization indicated that the cancers contain subpopulations of cells with differing amounts of c-myc and H-ras amplification. The results are consistent with the idea that ionizing radiation produces carcinogenically relevant lesions via 2 repairable events at low LET and via a non-repairable, linked event pathway at high LET; either pathway may advance the cell by 1 stage in the multistage model. The model, if validated, permits the direct calculation of cancer risk in rat skin in a way that can be subjected to experimental testing.

  17. Estimates of Radiation Effects on Cancer Risks in the Mayak Worker, Techa River and Atomic Bomb Survivor Studies.

    PubMed

    Preston, Dale L; Sokolnikov, Mikhail E; Krestinina, Lyudmila Yu; Stram, Daniel O

    2016-11-24

    For almost 50 y, the Life Span Study cohort of atomic bomb survivor studies has been the primary source of the quantitative estimates of cancer and non-cancer risks that form the basis of international radiation protection standards. However, the long-term follow-up and extensive individual dose reconstruction for the Russian Mayak worker cohort (MWC) and Techa River cohort (TRC) are providing quantitative information about radiation effects on cancer risks that complement the atomic bomb survivor-based risk estimates. The MWC, which includes ~26 000 men and women who began working at Mayak between 1948 and 1982, is the primary source for estimates of the effects of plutonium on cancer risks and also provides information on the effects of low-dose rate external gamma exposures. The TRC consists of ~30 000 men and women of all ages who received low-dose-rate, low-dose exposures as a consequence of Mayak's release of radioactive material into the Techa River. The TRC data are of interest because the exposures are broadly similar to those experienced by populations exposed as a consequence of nuclear accidents such as Chernobyl. In this presentation, it is described the strengths and limitations of these three cohorts, outline and compare recent solid cancer and leukemia risk estimates and discussed why information from the Mayak and Techa River studies might play a role in the development and refinement of the radiation risk estimates that form the basis for radiation protection standards.

  18. A framework for estimating radiation-related cancer risks in Japan from the 2011 Fukushima nuclear accident.

    PubMed

    Walsh, L; Zhang, W; Shore, R E; Auvinen, A; Laurier, D; Wakeford, R; Jacob, P; Gent, N; Anspaugh, L R; Schüz, J; Kesminiene, A; van Deventer, E; Tritscher, A; del Rosarion Pérez, M

    2014-11-01

    We present here a methodology for health risk assessment adopted by the World Health Organization that provides a framework for estimating risks from the Fukushima nuclear accident after the March 11, 2011 Japanese major earthquake and tsunami. Substantial attention has been given to the possible health risks associated with human exposure to radiation from damaged reactors at the Fukushima Daiichi nuclear power station. Cumulative doses were estimated and applied for each post-accident year of life, based on a reference level of exposure during the first year after the earthquake. A lifetime cumulative dose of twice the first year dose was estimated for the primary radionuclide contaminants ((134)Cs and (137)Cs) and are based on Chernobyl data, relative abundances of cesium isotopes, and cleanup efforts. Risks for particularly radiosensitive cancer sites (leukemia, thyroid and breast cancer), as well as the combined risk for all solid cancers were considered. The male and female cumulative risks of cancer incidence attributed to radiation doses from the accident, for those exposed at various ages, were estimated in terms of the lifetime attributable risk (LAR). Calculations of LAR were based on recent Japanese population statistics for cancer incidence and current radiation risk models from the Life Span Study of Japanese A-bomb survivors. Cancer risks over an initial period of 15 years after first exposure were also considered. LAR results were also given as a percentage of the lifetime baseline risk (i.e., the cancer risk in the absence of radiation exposure from the accident). The LAR results were based on either a reference first year dose (10 mGy) or a reference lifetime dose (20 mGy) so that risk assessment may be applied for relocated and non-relocated members of the public, as well as for adult male emergency workers. The results show that the major contribution to LAR from the reference lifetime dose comes from the first year dose. For a dose of 10 mGy in

  19. Sensitivity Analysis of Median Lifetime on Radiation Risks Estimates for Cancer and Circulatory Disease amongst Never-Smokers

    NASA Technical Reports Server (NTRS)

    Chappell, Lori J.; Cucinotta, Francis A.

    2011-01-01

    Radiation risks are estimated in a competing risk formalism where age or time after exposure estimates of increased risks for cancer and circulatory diseases are folded with a probability to survive to a given age. The survival function, also called the life-table, changes with calendar year, gender, smoking status and other demographic variables. An outstanding problem in risk estimation is the method of risk transfer between exposed populations and a second population where risks are to be estimated. Approaches used to transfer risks are based on: 1) Multiplicative risk transfer models -proportional to background disease rates. 2) Additive risk transfer model -risks independent of background rates. In addition, a Mixture model is often considered where the multiplicative and additive transfer assumptions are given weighted contributions. We studied the influence of the survival probability on the risk of exposure induced cancer and circulatory disease morbidity and mortality in the Multiplicative transfer model and the Mixture model. Risks for never-smokers (NS) compared to the average U.S. population are estimated to be reduced between 30% and 60% dependent on model assumptions. Lung cancer is the major contributor to the reduction for NS, with additional contributions from circulatory diseases and cancers of the stomach, liver, bladder, oral cavity, esophagus, colon, a portion of the solid cancer remainder, and leukemia. Greater improvements in risk estimates for NS s are possible, and would be dependent on improved understanding of risk transfer models, and elucidating the role of space radiation on the various stages of disease formation (e.g. initiation, promotion, and progression).

  20. REVIEW OF DRAFT REVISED BLUE BOOK ON ESTIMATING CANCER RISKS FROM EXPOSURE TO IONIZING RADIATION

    EPA Science Inventory

    In 1994, EPA published a report, referred to as the “Blue Book,” which lays out EPA’s current methodology for quantitatively estimating radiogenic cancer risks. A follow-on report made minor adjustments to the previous estimates and presented a partial analysis of the uncertainti...

  1. Space Radiation Cancer Risks

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.

    2007-01-01

    Space radiation presents major challenges to astronauts on the International Space Station and for future missions to the Earth s moon or Mars. Methods used to project risks on Earth need to be modified because of the large uncertainties in projecting cancer risks from space radiation, and thus impact safety factors. We describe NASA s unique approach to radiation safety that applies uncertainty based criteria within the occupational health program for astronauts: The two terrestrial criteria of a point estimate of maximum acceptable level of risk and application of the principle of As Low As Reasonably Achievable (ALARA) are supplemented by a third requirement that protects against risk projection uncertainties using the upper 95% confidence level (CL) in the radiation cancer projection model. NASA s acceptable level of risk for ISS and their new lunar program have been set at the point-estimate of a 3-percent risk of exposure induced death (REID). Tissue-averaged organ dose-equivalents are combined with age at exposure and gender-dependent risk coefficients to project the cumulative occupational radiation risks incurred by astronauts. The 95% CL criteria in practice is a stronger criterion than ALARA, but not an absolute cut-off as is applied to a point projection of a 3% REID. We describe the most recent astronaut dose limits, and present a historical review of astronaut organ doses estimates from the Mercury through the current ISS program, and future projections for lunar and Mars missions. NASA s 95% CL criteria is linked to a vibrant ground based radiobiology program investigating the radiobiology of high-energy protons and heavy ions. The near-term goal of research is new knowledge leading to the reduction of uncertainties in projection models. Risk projections involve a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. The current model for projecting space radiation

  2. Ionizing radiation bioeffects and risks

    SciTech Connect

    1992-12-31

    Radiation protection requires an understanding of the prompt and long-term biological effects of radiation and numerical estimates of radiation risks. This chapter presents the characteristics of the ``acute radiation syndrome`` which can occur if an individual is exposed to high doses of radiation, and the effects of high levels of radiation on the skin. It also describes the long term bioeffects of low levels of low LET radiation on individuals and the whole population. These risks are quantified and are put in perspective by comparison to other societal hazards.

  3. Radiation Exposure to Patient and Staff in Hepatic Chemoembolization: Risk Estimation of Cancer and Deterministic Effects

    SciTech Connect

    Hidajat, Nico Wust, Peter; Felix, Roland; Schroeder, Ralf Juergen

    2006-10-15

    The purpose of the study was to determine the risks of radiation-induced cancer and deterministic effects for the patient and staff in transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). Sixty-five patients with HCC underwent the first cycle of TACE. Thermoluminescence dosemeters and conversion factors were used to measure surface doses and to calculate organ doses and effective dose. For the patient, the risk of fatal cancer and severe genetic defect was in the magnitude of 10{sup -4} and 10{sup -5}, respectively. Five patients showed surface doses over the first lumbar vertebra exceeding 2000 mSv and 45 patients showed doses over the spine or the liver region above 500 mSv. The risk of fatal cancer and severe genetic defect for the radiologist and assistant was in the magnitude of 10{sup -7} to 10{sup -8}. They could exceed the threshold for lens opacity in the case of more than 490 and 1613 TACE yearly for a period of many years, respectively. Radiation dose could lead to local transient erythema and/or local depression of hematopoiesis in many patients after TACE. For the radiologist and assistant, risk of fatal cancer and genetic defect and lens opacity might arise when they perform interventions such as TACE intensively.

  4. Risks of circulatory diseases among Mayak PA workers with radiation doses estimated using the improved Mayak Worker Dosimetry System 2008.

    PubMed

    Moseeva, Maria B; Azizova, Tamara V; Grigoryeva, Evgenia S; Haylock, Richard

    2014-05-01

    The new Mayak Worker Dosimetry System 2008 (MWDS-2008) was published in 2013 and supersedes the Doses-2005 dosimetry system for Mayak Production Association (PA) workers. It provides revised external and internal dose estimates based on the updated occupational history data. Using MWDS-2008, a cohort of 18,856 workers first employed at one of the main Mayak PA plants during 1948-1972 and followed up to 2005 was identified. Incidence and mortality risks from ischemic heart disease (IHD) (International Classification of Diseases (ICD)-9 codes 410-414) and from cerebrovascular diseases (CVD) (ICD-9 codes 430-438) were examined in this cohort and compared with previously published risk estimates in the same cohort based on the Doses-2005 dosimetry system. Significant associations were observed between doses from external gamma-rays and IHD and CVD incidence and also between internal doses from alpha-radiation and IHD mortality and CVD incidence. The estimates of excess relative risk (ERR)/Gy were consistent with those estimates from the previous studies based on Doses-2005 system apart from the relationship between CVD incidence and internal liver dose where the ERR/Gy based on MWDS-2008 was just over three times higher than the corresponding estimate based on Doses-2005 system. Adjustment for smoking status did not show any effect on the estimates of risk from internal alpha-particle exposure.

  5. Use of risk projection models to estimate mortality and incidence from radiation-induced breast cancer in screening programs

    NASA Astrophysics Data System (ADS)

    Ramos, M.; Ferrer, S.; Villaescusa, J. I.; Verdú, G.; Salas, M. D.; Cuevas, M. D.

    2005-02-01

    The authors report on a method to calculate radiological risks, applicable to breast screening programs and other controlled medical exposures to ionizing radiation. In particular, it has been applied to make a risk assessment in the Valencian Breast Cancer Early Detection Program (VBCEDP) in Spain. This method is based on a parametric approach, through Markov processes, of hazard functions for radio-induced breast cancer incidence and mortality, with mean glandular breast dose, attained age and age-at-exposure as covariates. Excess relative risk functions of breast cancer mortality have been obtained from two different case-control studies exposed to ionizing radiation, with different follow-up time: the Canadian Fluoroscopy Cohort Study (1950-1987) and the Life Span Study (1950-1985 and 1950-1990), whereas relative risk functions for incidence have been obtained from the Life Span Study (1958-1993), the Massachusetts tuberculosis cohorts (1926-1985 and 1970-1985), the New York post-partum mastitis patients (1930-1981) and the Swedish benign breast disease cohort (1958-1987). Relative risks from these cohorts have been transported to the target population undergoing screening in the Valencian Community, a region in Spain with about four and a half million inhabitants. The SCREENRISK software has been developed to estimate radiological detriments in breast screening. Some hypotheses corresponding to different screening conditions have been considered in order to estimate the total risk associated with a woman who takes part in all screening rounds. In the case of the VBCEDP, the total radio-induced risk probability for fatal breast cancer is in a range between [5 × 10-6, 6 × 10-4] versus the natural rate of dying from breast cancer in the Valencian Community which is 9.2 × 10-3. The results show that these indicators could be included in quality control tests and could be adequate for making comparisons between several screening programs.

  6. Ionizing radiation and genetic risks. XIII. Summary and synthesis of papers VI to XII and estimates of genetic risks in the year 2000.

    PubMed

    Sankaranarayanan, K; Chakraborty, R

    2000-10-16

    This paper recapitulates the advances in the field of genetic risk estimation that have occurred during the past decade and using them as a basis, presents revised estimates of genetic risks of exposure to radiation. The advances include: (i) an upward revision of the estimates of incidence for Mendelian diseases (2.4% now versus 1.25% in 1993); (ii) the introduction of a conceptual change for calculating doubling doses; (iii) the elaboration of methods to estimate the mutation component (i.e. the relative increase in disease frequency per unit relative increase in mutation rate) and the use of the estimates obtained through these methods for assessing the impact of induced mutations on the incidence of Mendelian and chronic multifactorial diseases; (iv) the introduction of an additional factor called the "potential recoverability correction factor" in the risk equation to bridge the gap between radiation-induced mutations that have been recovered in mice and the risk of radiation-inducible genetic disease in human live births and (v) the introduction of the concept that the adverse effects of radiation-induced genetic damage are likely to be manifest predominantly as multi-system developmental abnormalities in the progeny. For all classes of genetic disease (except congenital abnormalities), the estimates of risk have been obtained using a doubling dose of 1 Gy. For a population exposed to low LET, chronic/ low dose irradiation, the current estimates for the first generation progeny are the following (all estimates per million live born progeny per Gy of parental irradiation): autosomal dominant and X-linked diseases, approximately 750-1500 cases; autosomal recessive, nearly zero and chronic multifactorial diseases, approximately 250-1200 cases. For congenital abnormalities, the estimate is approximately 2000 cases and is based on mouse data on developmental abnormalities. The total risk per Gy is of the order of approximately 3000-4700 cases which represent

  7. Estimate of the risk of radiation-induced cancers after linear-accelerator-based breast-cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Koh, Eui Kwan; Seo, Jungju; Baek, Tae Seong; Chung, Eun Ji; Yoon, Myonggeun; Lee, Hyun-ho

    2013-07-01

    The aim of this study is to assess and compare the excess absolute risks (EARs) of radiation-induced cancers following conformal (3D-CRT), fixed-field intensity-modulated (IMRT) and volumetric modulated arc (RapidArc) radiation therapy in patients with breast cancer. 3D-CRT, IMRT and RapidArc were planned for 10 breast cancer patients. The organ-specific EAR for cancer induction was estimated using the organ equivalent dose (OED) based on computed dose volume histograms (DVHs) and the secondary doses measured at various points from the field edge. The average secondary dose per Gy treatment dose from 3D-CRT, measured 10 to 50 cm from the field edge, ranged from 8.27 to 1.04 mGy. The secondary doses per Gy from IMRT and RapidArc, however, ranged between 5.86 and 0.54 mGy, indicating that IMRT and RapidArc are associated with smaller doses of secondary radiation than 3D-CRT. The organ specific EARs for out-of-field organs, such as the thyroid, liver and colon, were higher with 3D-CRT than with IMRT or RapidArc. In contrast, EARs for in-field organs were much lower with 3D-CRT than with IMRT or RapidArc. The overall estimate of EAR indicated that the radiation-induced cancer risk was 1.8-2.0 times lower with 3D-CRT than with IMRT or RapidArc. Comparisons of EARs during breast irradiation suggested that the predicted risk of secondary cancers was lower with 3D-CRT than with IMRT or RapidArc.

  8. Improved radiation dosimetry/risk estimates to facilitate environmental management of plutonium contaminated sites. 1998 annual progress report

    SciTech Connect

    Scott, B.R.

    1998-06-01

    'The objective of this research is to evaluate distributions of possible alpha radiation doses to the lung, bone, and liver and associated health-risk distributions for plutonium (Pu) inhalation-exposure scenarios relevant to environmental management of PuO{sub 2}-contaminated sites. Currently available dosimetry/risk models do not apply to exposure scenarios where, at most, a small number of highly radioactive PuO{sub 2} particles are inhaled (stochastic exposure [SE] paradigm). For the SE paradigm, risk distributions are more relevant than point estimates of risk. The focus of the research is on the SE paradigm and on high specific activity, alpha-emitting (HSA-aE) particles such as 238 PuO{sub 2} . The scientific goal is to develop a stochastic respiratory tract dosimetry/risk computer model for evaluating the desired absorbed dose distributions and associated health-risk distributions, for Department of Energy (DOE) workers and members of the public. This report summarizes results after 1 year of a 2-year project.'

  9. Cancer risks after radiation exposures

    SciTech Connect

    Voelz, G.L.

    1980-01-01

    A general overview of the effects of ionizing radiation on cancer induction is presented. The relationship between the degree of risk and absorbed dose is examined. Mortality from radiation-induced cancer in the US is estimated and percentages attributable to various sources are given. (ACR)

  10. Geosciences help to protect human health: estimation of the adsorbed radiation doses while flight journeys, as important step to radiation risk assessment

    NASA Astrophysics Data System (ADS)

    Chernov, Anatolii; Shabatura, Olexandr

    2016-04-01

    Estimation of the adsorbed radiation dose while flight journeys is a complex problem, which should be solved to get correct evaluation of equivalent effective doses and radiation risk assessment. Direct measurements of the adsorbed dose in the aircrafts during regional flights (3-10 hours) has shown that the radiation in the plane may increase 10-15 times (to 2-4 mSv/h) compared to the values on the surface of the Earth (0.2-0.5 mSv/h). Results of instrumental research confirmed by the other investigations. It is a fact that adsorbed doses per year while flight journeys are less than doses from medical tests. However, while flight journeys passengers get the same doses as nuclear power plant staff, people in zones of natural radiation anomalies and so should be evaluated. According to the authors' research, flight journeys are safe enough, when solar activity is normal and if we fly under altitude of 18 km (as usual, while intercontinental flights). Most of people travel by plane not so often, but if flight is lasting in dangerous periods of solar activity (powerful solar winds and magnetic field storms), passengers and flight crew can adsorb great amount of radiation doses. People, who spend more than 500 hours in flight journeys (pilots, business oriented persons', government representatives, etc.) get amount of radiation, which can negatively influence on health and provoke diseases, such as cancer. Authors consider that problem actual and researches are still going on. It is revealed, that radiation can be calculated, using special equations. Great part of radiation depends on very variable outer-space component and less variable solar. Accurate calculations of doses will be possible, when we will take into account all features of radiation distribution (time, season of year and exact time of the day, duration of flight), technical features of aircraft and logistics of flight (altitude, latitude). Results of first attempts of radiation doses modelling confirmed

  11. InterCardioRisk: a novel online tool for estimating doses of ionising radiation to occupationally-exposed medical staff and their associated health risks.

    PubMed

    Moriña, David; Grellier, James; Carnicer, Adela; Pernot, Eileen; Ryckx, Nick; Cardis, Elisabeth

    2016-09-01

    Those working in interventional cardiology and related medical procedures are potentially subject to considerable exposure to x-rays. Two types of tissue of particular concern that may receive considerable doses during such procedures are the lens of the eye and the brain. Ocular radiation exposure results in lens changes that, with time, may progress to partial or total lens opacification (cataracts). In the early stages, such opacities do not result in visual disability; the severity of such changes tends to increase progressively with dose and time until vision is impaired and cataract surgery is required. Scattered radiation doses to the eye lens of an interventional cardiologist in typical working conditions can exceed 34 μGy min(-1) in high-dose fluoroscopy modes and 3 μGy per image during image acquisition (instantaneous rate values) when radiation protection tools are not used. A causal relation between exposure to ionising radiation and increased risk of brain and central nervous system tumours has been shown in a number of studies. Although absorbed doses to the brain in interventional cardiology procedures are lower than those to the eye lens by a factor between 3.40 and 8.08 according to our simulations, doses to both tissues are among the highest occupational radiation doses documented for medical staff whose work involves exposures to x-rays. We present InterCardioRisk, a tool featuring an easy-to-use web interface that provides a general estimation of both cumulated absorbed doses experienced by medical staff exposed in the interventional cardiology setting and their estimated associated health risks. The tool is available at http://intercardiorisk.creal.cat.

  12. Space Radiation Cancer, Circulatory Disease and CNS Risks for Near Earth Asteroid and Mars Missions: Uncertainty Estimates for Never-Smokers

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Chappell, Lori J.; Wang, Minli; Kim, Myung-Hee

    2011-01-01

    The uncertainties in estimating the health risks from galactic cosmic rays (GCR) and solar particle events (SPE) are a major limitation to the length of space missions and the evaluation of potential risk mitigation approaches. NASA limits astronaut exposures to a 3% risk of exposure induced cancer death (REID), and protects against uncertainties in risks projections using an assessment of 95% confidence intervals after propagating the error from all model factors (environment and organ exposure, risk coefficients, dose-rate modifiers, and quality factors). Because there are potentially significant late mortality risks from diseases of the circulatory system and central nervous system (CNS) which are less well defined than cancer risks, the cancer REID limit is not necessarily conservative. In this report, we discuss estimates of lifetime risks from space radiation and new estimates of model uncertainties are described. The key updates to the NASA risk projection model are: 1) Revised values for low LET risk coefficients for tissue specific cancer incidence, with incidence rates transported to an average U.S. population to estimate the probability of Risk of Exposure Induced Cancer (REIC) and REID. 2) An analysis of smoking attributable cancer risks for never-smokers that shows significantly reduced lung cancer risk as well as overall cancer risks from radiation compared to risk estimated for the average U.S. population. 3) Derivation of track structure based quality functions depends on particle fluence, charge number, Z and kinetic energy, E. 4) The assignment of a smaller maximum in quality function for leukemia than for solid cancers. 5) The use of the ICRP tissue weights is shown to over-estimate cancer risks from SPEs by a factor of 2 or more. Summing cancer risks for each tissue is recommended as a more accurate approach to estimate SPE cancer risks. 6) Additional considerations on circulatory and CNS disease risks. Our analysis shows that an individual s

  13. Organ-specific radiation-induced cancer risk estimates due to radiotherapy for benign pigmented villonodular synovitis

    NASA Astrophysics Data System (ADS)

    Mazonakis, Michalis; Tzedakis, Antonis; Lyraraki, Efrossyni; Damilakis, John

    2016-09-01

    Pigmented villonodular synovitis (PVNS) is a benign disease affecting synovial membranes of young and middle-aged adults. The aggressive treatment of this disorder often involves external-beam irradiation. This study was motivated by the lack of data relating to the radiation exposure of healthy tissues and radiotherapy-induced cancer risk. Monte Carlo methodology was employed to simulate a patient’s irradiation for PVNS in the knee and hip joints with a 6 MV photon beam. The average radiation dose received by twenty-two out-of-field critical organs of the human body was calculated. These calculations were combined with the appropriate organ-, age- and gender-specific risk coefficients of the BEIR-VII model to estimate the lifetime probability of cancer development. The risk for carcinogenesis to colon, which was partly included in the treatment fields used for hip irradiation, was determined with a non-linear mechanistic model and differential dose-volume histograms obtained by CT-based 3D radiotherapy planning. Risk assessments were compared with the nominal lifetime intrinsic risk (LIR) values. Knee irradiation to 36 Gy resulted in out-of-field organ doses of 0.2-24.6 mGy. The corresponding range from hip radiotherapy was 1.2-455.1 mGy whereas the organ equivalent dose for the colon was up to 654.9 mGy. The organ-specific cancer risks from knee irradiation for PVNS were found to be inconsequential since they were at least 161.5 times lower than the LIRs irrespective of the patient’s age and gender. The bladder and colon cancer risk from radiotherapy in the hip joint was up to 3.2 and 6.6 times smaller than the LIR, respectively. These cancer risks may slightly elevate the nominal incidence rates and they should not be ignored during the patient’s treatment planning and follow-up. The probabilities for developing any other solid tumor were more than 20 times lower than the LIRs and, therefore, they may be considered as small.

  14. Radiation risks and dirty bombs.

    PubMed

    Ring, Joseph P

    2004-02-01

    For many, the thought of terrorists detonating a dirty bomb--a radiological dispersal device--is frightening. However, the radiation health risks from such an occurrence are small. For most people directly involved, the exposure would have an estimated lifetime health risk that is comparable to the health risk from smoking five packages of cigarettes or the accident risk from taking a hike. The actual impact of a dirty bomb would be economic and social (NCRP 2001). There would be an economic cost for clean-up as well as a decrease in economic activity in the affected area due to radiation fear. If such a bomb were detonated, those exposed as well as those not exposed would have great concern about potential health effects while seeking medical attention and avoiding the impacted area. This paper discusses the health risks from radiation exposure and compares them to risks from various activities of daily life and to exposure to hazardous chemicals.

  15. Effect of induction chemotherapy on estimated risk of radiation pneumonitis in bulky non–small cell lung cancer

    SciTech Connect

    Amin, Neha P.; Miften, Moyed; Thornton, Dale; Ryan, Nicole; Kavanagh, Brian; Gaspar, Laurie E

    2013-10-01

    Patients with bulky non–small cell lung cancer (NSCLC) may be at a high risk for radiation pneumonitis (RP) if treated with up-front concurrent chemoradiation. There is limited information about the effect of induction chemotherapy on the volume of normal lung subsequently irradiated. This study aims to estimate the reduction in risk of RP in patients with NSCLC after receiving induction chemotherapy. Between 2004 and 2009, 25 patients with Stage IV NSCLC were treated with chemotherapy alone (no surgery or radiation therapy [RT]) and had computed tomography (CT) scans before and after 2 cycles of chemotherapy. Simulated RT plans were created for the prechemotherapy and postchemotherapy scans so as to deliver 60 Gy to the thoracic disease in patients who had either a >20% volumetric increase or decrease in gross tumor volume (GTV) from chemotherapy. The prechemotherapy and postchemotherapy scans were analyzed to compare the percentage of lung volume receiving≥20 Gy (V20), mean lung dose (MLD), and normal tissue complication probability (NTCP). Eight patients (32%) had a GTV reduction >20%, 2 (8%) had GTV increase >20%, and 15 (60%) had stable GTV. In the 8 responders, there was an absolute median GTV decrease of 88.1 cc (7.3 to 351.6 cc) or a 48% (20% to 62%) relative reduction in tumor burden. One had >20% tumor progression during chemotherapy, yet had an improvement in dosimetric parameters postchemotherapy. Among these 9 patients, the median decrease in V20, MLD, and NTCP was 2.6% (p<0.01), 2.1 Gy (p<0.01), and 5.6% (p<0.01), respectively. Less than one-third of patients with NSCLC obtain >20% volumetric tumor reduction from chemotherapy alone. Even with that amount of volumetric reduction, the 5% reduced risk of RP was only modest and did not convert previously ineligible patients to safely receive definitive thoracic RT.

  16. Radiation Leukemogenesis: Applying Basic Science of Epidemiological Estimates of Low Dose Risks and Dose-Rate Effects

    SciTech Connect

    Hoel, D. G.

    1998-11-01

    The next stage of work has been to examine more closely the A-bomb leukemia data which provides the underpinnings of the risk estimation of CML in the above mentioned manuscript. The paper by Hoel and Li (Health Physics 75:241-50) shows how the linear-quadratic model has basic non-linearities at the low dose region for the leukemias including CML. Pierce et. al., (Radiation Research 123:275-84) have developed distributions for the uncertainty in the estimated exposures of the A-bomb cohort. Kellerer, et. al., (Radiation and Environmental Biophysics 36:73-83) has further considered possible errors in the estimated neutron values and with changing RBE values with dose and has hypothesized that the tumor response due to gamma may not be linear. We have incorporated his neutron model and have constricted new A-bomb doses based on his model adjustments. The Hoel and Li dose response analysis has also been applied using the Kellerer neutron dose adjustments for the leukemias. Finally, both Pierce's dose uncertainties and Kellerer neutron adjustments are combined as well as the varying RBE with dose as suggested by Rossi and Zaider and used for leukemia dose-response analysis. First the results of Hoel and Li showing a significantly improved fit of the linear-quadratic dose response by the inclusion of a threshold (i.e. low-dose nonlinearity) persisted. This work has been complete for both solid tumor as well as leukemia for both mortality as well as incidence data. The results are given in the manuscript described below which has been submitted to Health Physics.

  17. Improved Radiation Dosimetry/Risk Estimates to Facilitate Environmental Management of Plutonium Contaminated Sites

    SciTech Connect

    Scott, Bobby R.; Cheng, Yung-Sung; Zhou, Yue; Tokarskaya, Zoya B.; Zhuntova, Galina V.

    2003-06-11

    Our Phase II research evaluated health risks associated with inhaled plutonium. Our research objectives were to: (1) extend our stochastic model for deposition of plutonium in the respiratory tract to include additional key variability and uncertainty; (2) generate and analyze risk distributions for deterministic effects in the lung from inhaled plutonium that reflect risk model uncertainty; (3) acquire an improved understanding of key physiological effects of inhaled plutonium, based on evaluations of clinical data (e.g., hematological, respiratory function, chromosomal aberrations in lymphocytes) for Mayak workers in Russia who inhaled plutonium-239; (4) develop biological dosimetry for plutonium-239 that was inhaled by some Mayak workers (with unknown intake) based on clinical data for other workers with known plutonium-239 intake; (5) critically evaluate the validity of the linear no-threshold (LNT) risk model as it relates to cancer risks from inhaled plutonium-239 (base d on Mayak worker data); and (6) evaluate respirator filter penetration frequencies for airborne plutonium aerosols using surrogate high-density metals.

  18. Ionizing Radiation and Its Risks

    PubMed Central

    Goldman, Marvin

    1982-01-01

    Penetrating ionizing radiation fairly uniformly puts all exposed molecules and cells at approximately equal risk for deleterious consequences. Thus, the original deposition of radiation energy (that is, the dose) is unaltered by metabolic characteristics of cells and tissue, unlike the situation for chemical agents. Intensely ionizing radiations, such as neutrons and alpha particles, are up to ten times more damaging than sparsely ionizing sources such as x-rays or gamma rays for equivalent doses. Furthermore, repair in cells and tissues can ameliorate the consequences of radiation doses delivered at lower rates by up to a factor of ten compared with comparable doses acutely delivered, especially for somatic (carcinogenic) and genetic effects from x- and gamma-irradiation exposure. Studies on irradiated laboratory animals or on people following occupational, medical or accidental exposures point to an average lifetime fatal cancer risk of about 1 × 10-4 per rem of dose (100 per 106 person-rem). Leukemia and lung, breast and thyroid cancer seem more likely than other types of cancer to be produced by radiation. Radiation exposures from natural sources (cosmic rays and terrestrial radioactivity) of about 0.1 rem per year yield a lifetime cancer risk about 0.1 percent of the normally occurring 20 percent risk of cancer death. An increase of about 1 percent per rem in fatal cancer risk, or 200 rem to double the “background” risk rate, is compared with an estimate of about 100 rem to double the genetic risk. Newer data suggest that the risks for low-level radiation are lower than risks estimated from data from high exposures and that the present 5 rem per year limit for workers is adequate. PMID:6761969

  19. Multiparametric Determination of Radiation Risk

    NASA Technical Reports Server (NTRS)

    Richmond, Robert C.

    2003-01-01

    Predicting risk of human cancer following exposure to ionizing space radiation is challenging in part because of uncertainties of low-dose distribution amongst cells, of unknown potentially synergistic effects of microgravity upon cellular protein-expression, and of processing dose-related damage within cells to produce rare and late-appearing malignant transformation, degrade the confidence of cancer risk-estimates. The NASA- specific responsibility to estimate the risks of radiogenic cancer in a limited number of astronauts is not amenable to epidemiologic study, thereby increasing this challenge. Developing adequately sensitive cellular biodosimeters that simultaneously report 1) the quantity of absorbed close after exposure to ionizing radiation, 2) the quality of radiation delivering that dose, and 3) the risk of developing malignant transformation by the cells absorbing that dose could be useful for resolving these challenges. Use of a multiparametric cellular biodosimeter is suggested using analyses of gene-expression and protein-expression whereby large datasets of cellular response to radiation-induced damage are obtained and analyzed for expression-profiles correlated with established end points and molecular markers predictive for cancer-risk. Analytical techniques of genomics and proteomics may be used to establish dose-dependency of multiple gene- and protein- expressions resulting from radiation-induced cellular damage. Furthermore, gene- and protein-expression from cells in microgravity are known to be altered relative to cells grown on the ground at 1g. Therefore, hypotheses are proposed that 1) macromolecular expression caused by radiation-induced damage in cells in microgravity may be different than on the ground, and 2) different patterns of macromolecular expression in microgravity may alter human radiogenic cancer risk relative to radiation exposure on Earth. A new paradigm is accordingly suggested as a national database wherein genomic and

  20. Estimates of relative risks for cancers in a population after prolonged low-dose-rate radiation exposure: a follow-up assessment from 1983 to 2005.

    PubMed

    Hwang, Su-Lun; Hwang, Jing-Shiang; Yang, Yi-Ta; Hsieh, Wanhua A; Chang, Tien-Chun; Guo, How-Ran; Tsai, Mong-Hsun; Tang, Jih-Luh; Lin, I-Feng; Chang, Wushou Peter

    2008-08-01

    Radiation effects on cancer risks in a cohort of Taiwanese residents who received protracted low-dose-rate gamma-radiation exposures from (60)Co-contaminated reinforcing steel used to build their apartments were studied, and risks were compared to those in other radiation-exposed cohorts. Analyses were based on a more extended follow-up of the cohort population in which 117 cancer cases diagnosed between 1983 and 2005 among 6,242 people with an average excess cumulative exposure estimate of about 48 mGy. Cases were identified from Taiwan's National Cancer Registry. Radiation effects on cancer risk were estimated using proportional hazards models and were summarized in terms of the hazard ratio associated with a 100-mGy increase in dose (HR(100mGy)). A significant radiation risk was observed for leukemia excluding chronic lymphocytic leukemia (HR(100mGy) 1.19, 90% CI 1.01-1.31). Breast cancer exhibited a marginally significant dose response (HR(100mGy) 1.12, 90% CI 0.99-1.21). The results further strengthen the association between protracted low-dose radiation and cancer risks, especially for breast cancers and leukemia, in this unique cohort population.

  1. Systematic Review and Meta-analysis of Circulatory Disease from Exposure to Low-Level Ionizing Radiation and Estimates of Potential Population Mortality Risks

    PubMed Central

    Azizova, Tamara V.; Bazyka, Dimitry; Bouffler, Simon D.; Cardis, Elisabeth; Chekin, Sergey; Chumak, Vadim V.; Cucinotta, Francis A.; de Vathaire, Florent; Hall, Per; Harrison, John D.; Hildebrandt, Guido; Ivanov, Victor; Kashcheev, Valeriy V.; Klymenko, Sergiy V.; Kreuzer, Michaela; Laurent, Olivier; Ozasa, Kotaro; Schneider, Thierry; Tapio, Soile; Taylor, Andrew M.; Tzoulaki, Ioanna; Vandoolaeghe, Wendy L.; Wakeford, Richard; Zablotska, Lydia B.; Zhang, Wei; Lipshultz, Steven E.

    2012-01-01

    Background: Although high doses of ionizing radiation have long been linked to circulatory disease, evidence for an association at lower exposures remains controversial. However, recent analyses suggest excess relative risks at occupational exposure levels. Objectives: We performed a systematic review and meta-analysis to summarize information on circulatory disease risks associated with moderate- and low-level whole-body ionizing radiation exposures. Methods: We conducted PubMed/ISI Thomson searches of peer-reviewed papers published since 1990 using the terms “radiation” AND “heart” AND “disease,” OR “radiation” AND “stroke,” OR “radiation” AND “circulatory” AND “disease.” Radiation exposures had to be whole-body, with a cumulative mean dose of < 0.5 Sv, or at a low dose rate (< 10 mSv/day). We estimated population risks of circulatory disease from low-level radiation exposure using excess relative risk estimates from this meta-analysis and current mortality rates for nine major developed countries. Results: Estimated excess population risks for all circulatory diseases combined ranged from 2.5%/Sv [95% confidence interval (CI): 0.8, 4.2] for France to 8.5%/Sv (95% CI: 4.0, 13.0) for Russia. Conclusions: Our review supports an association between circulatory disease mortality and low and moderate doses of ionizing radiation. Our analysis was limited by heterogeneity among studies (particularly for noncardiac end points), the possibility of uncontrolled confounding in some occupational groups by lifestyle factors, and higher dose groups (> 0.5 Sv) generally driving the observed trends. If confirmed, our findings suggest that overall radiation-related mortality is about twice that currently estimated based on estimates for cancer end points alone (which range from 4.2% to 5.6%/Sv for these populations). PMID:22728254

  2. Estimates of radiation doses in tissue and organs and risk of excess cancer in the single-course radiotherapy patients treated for ankylosing spondylitis in England and Wales

    SciTech Connect

    Fabrikant, J.I.; Lyman, J.T.

    1982-02-01

    The estimates of absorbed doses of x rays and excess risk of cancer in bone marrow and heavily irradiated sites are extremely crude and are based on very limited data and on a number of assumptions. Some of these assumptions may later prove to be incorrect, but it is probable that they are correct to within a factor of 2. The excess cancer risk estimates calculated compare well with the most reliable epidemiological surveys thus far studied. This is particularly important for cancers of heavily irradiated sites with long latent periods. The mean followup period for the patients was 16.2 y, and an increase in cancers of heavily irradiated sites may appear in these patients in the 1970s in tissues and organs with long latent periods for the induction of cancer. The accuracy of these estimates is severely limited by the inadequacy of information on doses absorbed by the tissues at risk in the irradiated patients. The information on absorbed dose is essential for an accurate assessment of dose-cancer incidence analysis. Furthermore, in this valuable series of irradiated patients, the information on radiation dosimetry on the radiotherapy charts is central to any reliable determination of somatic risks of radiation with regard to carcinogenesis in man. The work necessary to obtain these data is under way; only when they are available can more precise estimates of risk of cancer induction by radiation in man be obtained.

  3. Radiation risk in nuclear medicine.

    PubMed

    Adelstein, S James

    2014-05-01

    Given the central roles that anatomical and functional imaging now play in medical practice, there have been concerns about the increasing levels of radiation exposure and their potential hazards. Despite incomplete quantitative knowledge of the risks, it is prudent to think of radiation, even at low doses, as a potential, albeit weak, carcinogen. Thus, we are obliged to minimize its dose and optimize its benefits. Hopefully, time will clarify our estimates of the dangers. Until then, we should educate and assure our patients, their families, and colleagues that the risks have been taken into account and are well balanced by the benefits.

  4. Accepting space radiation risks.

    PubMed

    Schimmerling, Walter

    2010-08-01

    The human exploration of space inevitably involves exposure to radiation. Associated with this exposure are multiple risks, i.e., probabilities that certain aspects of an astronaut's health or performance will be degraded. The management of these risks requires that such probabilities be accurately predicted, that the actual exposures be verified, and that comprehensive records be maintained. Implicit in these actions is the fact that, at some point, a decision has been made to accept a certain level of risk. This paper examines ethical and practical considerations involved in arriving at a determination that risks are acceptable, roles that the parties involved may play, and obligations arising out of reliance on the informed consent paradigm seen as the basis for ethical radiation risk acceptance in space.

  5. Injury Risk Estimation Expertise

    PubMed Central

    Petushek, Erich J.; Ward, Paul; Cokely, Edward T.; Myer, Gregory D.

    2015-01-01

    Background: Simple observational assessment of movement is a potentially low-cost method for anterior cruciate ligament (ACL) injury screening and prevention. Although many individuals utilize some form of observational assessment of movement, there are currently no substantial data on group skill differences in observational screening of ACL injury risk. Purpose/Hypothesis: The purpose of this study was to compare various groups’ abilities to visually assess ACL injury risk as well as the associated strategies and ACL knowledge levels. The hypothesis was that sports medicine professionals would perform better than coaches and exercise science academics/students and that these subgroups would all perform better than parents and other general population members. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 428 individuals, including physicians, physical therapists, athletic trainers, strength and conditioning coaches, exercise science researchers/students, athletes, parents, and members of the general public participated in the study. Participants completed the ACL Injury Risk Estimation Quiz (ACL-IQ) and answered questions related to assessment strategy and ACL knowledge. Results: Strength and conditioning coaches, athletic trainers, physical therapists, and exercise science students exhibited consistently superior ACL injury risk estimation ability (+2 SD) as compared with sport coaches, parents of athletes, and members of the general public. The performance of a substantial number of individuals in the exercise sciences/sports medicines (approximately 40%) was similar to or exceeded clinical instrument-based biomechanical assessment methods (eg, ACL nomogram). Parents, sport coaches, and the general public had lower ACL-IQ, likely due to their lower ACL knowledge and to rating the importance of knee/thigh motion lower and weight and jump height higher. Conclusion: Substantial cross-professional/group differences in visual ACL

  6. Radiation dose estimates for radiopharmaceuticals

    SciTech Connect

    Stabin, M.G.; Stubbs, J.B.; Toohey, R.E.

    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.

  7. Ultraviolet Radiation: Human Exposure and Health Risks.

    ERIC Educational Resources Information Center

    Tenkate, Thomas D.

    1998-01-01

    Provides an overview of human exposure to ultraviolet radiation and associated health effects as well as risk estimates for acute and chronic conditions resulting from such exposure. Demonstrates substantial reductions in health risk that can be achieved through preventive actions. Also includes a risk assessment model for skin cancer. Contains 36…

  8. Acute radiation risk models

    NASA Astrophysics Data System (ADS)

    Smirnova, Olga

    Biologically motivated mathematical models, which describe the dynamics of the major hematopoietic lineages (the thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems) in acutely/chronically irradiated humans are developed. These models are implemented as systems of nonlinear differential equations, which variables and constant parameters have clear biological meaning. It is shown that the developed models are capable of reproducing clinical data on the dynamics of these systems in humans exposed to acute radiation in the result of incidents and accidents, as well as in humans exposed to low-level chronic radiation. Moreover, the averaged value of the "lethal" dose rates of chronic irradiation evaluated within models of these four major hematopoietic lineages coincides with the real minimal dose rate of lethal chronic irradiation. The demonstrated ability of the models of the human thrombocytopoietic, lymphocytopoietic, granulocytopoietic, and erythropoietic systems to predict the dynamical response of these systems to acute/chronic irradiation in wide ranges of doses and dose rates implies that these mathematical models form an universal tool for the investigation and prediction of the dynamics of the major human hematopoietic lineages for a vast pattern of irradiation scenarios. In particular, these models could be applied for the radiation risk assessment for health of astronauts exposed to space radiation during long-term space missions, such as voyages to Mars or Lunar colonies, as well as for health of people exposed to acute/chronic irradiation due to environmental radiological events.

  9. Space radiation and cardiovascular disease risk.

    PubMed

    Boerma, Marjan; Nelson, Gregory A; Sridharan, Vijayalakshmi; Mao, Xiao-Wen; Koturbash, Igor; Hauer-Jensen, Martin

    2015-12-26

    Future long-distance space missions will be associated with significant exposures to ionizing radiation, and the health risks of these radiation exposures during manned missions need to be assessed. Recent Earth-based epidemiological studies in survivors of atomic bombs and after occupational and medical low dose radiation exposures have indicated that the cardiovascular system may be more sensitive to ionizing radiation than was previously thought. This has raised the concern of a cardiovascular disease risk from exposure to space radiation during long-distance space travel. Ground-based studies with animal and cell culture models play an important role in estimating health risks from space radiation exposure. Charged particle space radiation has dense ionization characteristics and may induce unique biological responses, appropriate simulation of the space radiation environment and careful consideration of the choice of the experimental model are critical. Recent studies have addressed cardiovascular effects of space radiation using such models and provided first results that aid in estimating cardiovascular disease risk, and several other studies are ongoing. Moreover, astronauts could potentially be administered pharmacological countermeasures against adverse effects of space radiation, and research is focused on the development of such compounds. Because the cardiovascular response to space radiation has not yet been clearly defined, the identification of potential pharmacological countermeasures against cardiovascular effects is still in its infancy.

  10. Space radiation and cardiovascular disease risk

    PubMed Central

    Boerma, Marjan; Nelson, Gregory A; Sridharan, Vijayalakshmi; Mao, Xiao-Wen; Koturbash, Igor; Hauer-Jensen, Martin

    2015-01-01

    Future long-distance space missions will be associated with significant exposures to ionizing radiation, and the health risks of these radiation exposures during manned missions need to be assessed. Recent Earth-based epidemiological studies in survivors of atomic bombs and after occupational and medical low dose radiation exposures have indicated that the cardiovascular system may be more sensitive to ionizing radiation than was previously thought. This has raised the concern of a cardiovascular disease risk from exposure to space radiation during long-distance space travel. Ground-based studies with animal and cell culture models play an important role in estimating health risks from space radiation exposure. Charged particle space radiation has dense ionization characteristics and may induce unique biological responses, appropriate simulation of the space radiation environment and careful consideration of the choice of the experimental model are critical. Recent studies have addressed cardiovascular effects of space radiation using such models and provided first results that aid in estimating cardiovascular disease risk, and several other studies are ongoing. Moreover, astronauts could potentially be administered pharmacological countermeasures against adverse effects of space radiation, and research is focused on the development of such compounds. Because the cardiovascular response to space radiation has not yet been clearly defined, the identification of potential pharmacological countermeasures against cardiovascular effects is still in its infancy. PMID:26730293

  11. Real Time Radiation Exposure And Health Risks

    NASA Technical Reports Server (NTRS)

    Hu, Shaowen; Barzilla, Janet E.; Semones, Edward J.

    2015-01-01

    Radiation from solar particle events (SPEs) poses a serious threat to future manned missions outside of low Earth orbit (LEO). Accurate characterization of the radiation environment in the inner heliosphere and timely monitoring the health risks to crew are essential steps to ensure the safety of future Mars missions. In this project we plan to develop an approach that can use the particle data from multiple satellites and perform near real-time simulations of radiation exposure and health risks for various exposure scenarios. Time-course profiles of dose rates will be calculated with HZETRN and PDOSE from the energy spectrum and compositions of the particles archived from satellites, and will be validated from recent radiation exposure measurements in space. Real-time estimation of radiation risks will be investigated using ARRBOD. This cross discipline integrated approach can improve risk mitigation by providing critical information for risk assessment and medical guidance to crew during SPEs.

  12. Risk Factors: Radiation

    Cancer.gov

    Radiation of certain wavelengths, called ionizing radiation, has enough energy to damage DNA and cause cancer. Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation.

  13. Patient-specific radiation dose and cancer risk estimation in CT: Part I. Development and validation of a Monte Carlo program

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P.

    2011-01-15

    Purpose: Radiation-dose awareness and optimization in CT can greatly benefit from a dose-reporting system that provides dose and risk estimates specific to each patient and each CT examination. As the first step toward patient-specific dose and risk estimation, this article aimed to develop a method for accurately assessing radiation dose from CT examinations. Methods: A Monte Carlo program was developed to model a CT system (LightSpeed VCT, GE Healthcare). The geometry of the system, the energy spectra of the x-ray source, the three-dimensional geometry of the bowtie filters, and the trajectories of source motions during axial and helical scans were explicitly modeled. To validate the accuracy of the program, a cylindrical phantom was built to enable dose measurements at seven different radial distances from its central axis. Simulated radial dose distributions in the cylindrical phantom were validated against ion chamber measurements for single axial scans at all combinations of tube potential and bowtie filter settings. The accuracy of the program was further validated using two anthropomorphic phantoms (a pediatric one-year-old phantom and an adult female phantom). Computer models of the two phantoms were created based on their CT data and were voxelized for input into the Monte Carlo program. Simulated dose at various organ locations was compared against measurements made with thermoluminescent dosimetry chips for both single axial and helical scans. Results: For the cylindrical phantom, simulations differed from measurements by -4.8% to 2.2%. For the two anthropomorphic phantoms, the discrepancies between simulations and measurements ranged between (-8.1%, 8.1%) and (-17.2%, 13.0%) for the single axial scans and the helical scans, respectively. Conclusions: The authors developed an accurate Monte Carlo program for assessing radiation dose from CT examinations. When combined with computer models of actual patients, the program can provide accurate dose

  14. The risks of radiation

    NASA Astrophysics Data System (ADS)

    Miettenen, Jorma K.

    1988-01-01

    The risks of radioactivity are a really complicated matter, yet they are much better known than are the risks relating to thousands of chemical poisons that occur in our environment. The greatest mistakes are probably made in the definition of safety margins. Except for the bombs dropped in Japan and one other case in the Marshall Islands, there has always—luckily—been a wide safety margin between fallout radiation and doses dangerous to health; the margin has actually been about 1000-fold. The Chernobyl dose of 0.5 mGy/year that we received is only 1/1000 of the acute dose of 0.5 Gy which would cause a slight and nonpermanent change in the blood picture. There is no such safety margin with respect to many air pollutants. The safety standards for sulfuric or nitric oxides, ozone and so on, have been set only just below the level that already causes a health hazard, and these standards are exceeded once in a while. Otherwise, traffic would have to be forbidden and many industrial plants, especially power stations using coal, would have to stop working whenever a low-temperature inversion occurred. Environmental radioactivity does not represent a likely health risk in Finland unless a nuclear war breaks out. Air pollutants, on the contrary, are a real and almost daily health risk that should be carefully considered when decisions about our energy production are being made. In spite of what happened at Chernobyl, global consumption of nuclear power will double by the year 2000, since there are about 140 nuclear power plants presently under construction. It is not likely that another catastrophe like Chernobyl will happen, yet nuclear plant accidents are of course possible, even if their likelihood is diminished by improving reactor safety and even if any eventual damage could be expected to be smaller. If a reactor is hooded by a containment structure, no significant release of radioactive materials should be possible even in case of an accident. However, we must

  15. Calculating Risk: Radiation and Chernobyl.

    ERIC Educational Resources Information Center

    Gale, Robert Peter

    1987-01-01

    Considers who is at risk in a disaster such as Chernobyl. Assesses the difficulty in translating information regarding radiation to the public and in determining the acceptability of technological risks. (NKA)

  16. Methods for estimation of radiation risk in epidemiological studies accounting for classical and Berkson errors in doses.

    PubMed

    Kukush, Alexander; Shklyar, Sergiy; Masiuk, Sergii; Likhtarov, Illya; Kovgan, Lina; Carroll, Raymond J; Bouville, Andre

    2011-02-16

    With a binary response Y, the dose-response model under consideration is logistic in flavor with pr(Y=1 | D) = R (1+R)(-1), R = λ(0) + EAR D, where λ(0) is the baseline incidence rate and EAR is the excess absolute risk per gray. The calculated thyroid dose of a person i is expressed as Dimes=fiQi(mes)/Mi(mes). Here, Qi(mes) is the measured content of radioiodine in the thyroid gland of person i at time t(mes), Mi(mes) is the estimate of the thyroid mass, and f(i) is the normalizing multiplier. The Q(i) and M(i) are measured with multiplicative errors Vi(Q) and ViM, so that Qi(mes)=Qi(tr)Vi(Q) (this is classical measurement error model) and Mi(tr)=Mi(mes)Vi(M) (this is Berkson measurement error model). Here, Qi(tr) is the true content of radioactivity in the thyroid gland, and Mi(tr) is the true value of the thyroid mass. The error in f(i) is much smaller than the errors in ( Qi(mes), Mi(mes)) and ignored in the analysis. By means of Parametric Full Maximum Likelihood and Regression Calibration (under the assumption that the data set of true doses has lognormal distribution), Nonparametric Full Maximum Likelihood, Nonparametric Regression Calibration, and by properly tuned SIMEX method we study the influence of measurement errors in thyroid dose on the estimates of λ(0) and EAR. The simulation study is presented based on a real sample from the epidemiological studies. The doses were reconstructed in the framework of the Ukrainian-American project on the investigation of Post-Chernobyl thyroid cancers in Ukraine, and the underlying subpolulation was artificially enlarged in order to increase the statistical power. The true risk parameters were given by the values to earlier epidemiological studies, and then the binary response was simulated according to the dose-response model.

  17. [Quantification of radiation-induced genetic risk].

    PubMed

    Ehling, U H

    1987-05-01

    Associated with technical advances of our civilization is a radiation- and chemically-induced increase in the germ cell mutation rate in man. This would result in an increase in the frequency of genetic diseases and would be detrimental to future generations. It is the duty of our generation to keep this risk as low as possible. The estimation of the radiation-induced genetic risk of human populations is based on the extrapolation of results from animal experiments. Radiation-induced mutations are stochastic events. The probability of the event depends on the dose; the degree of the damage does not. The different methods to estimate the radiation-induced genetic risk will be discussed. The accuracy of the predicted results will be evaluated by a comparison with the observed incidence of dominant mutations in offspring born to radiation exposed survivors of the Hiroshima and Nagasaki atomic bombings. These methods will be used to predict the genetic damage from the fallout of the reactor accident at Chernobyl. For the exposure dose we used the upper limits of the mean effective life time equivalent dose from the fallout values in the Munich region. According to the direct method for the risk estimation we will expect for each 100 to 500 spontaneous dominant mutations one radiation-induced mutation in the first generation. With the indirect method we estimate a ratio of 100 dominant spontaneous mutations to one radiation-induced dominant mutation. The possibilities and the limitations of the different methods to estimate the genetic risk will be discussed. The discrepancy between the high safety standards for radiation protection and the low level of knowledge for the toxicological evaluation of chemical mutagens will be emphasized.

  18. Ionizing radiation and heart risks.

    PubMed

    Bhattacharya, Souparno; Asaithamby, Aroumougame

    2016-10-01

    Cardiovascular disease and cancer are the two leading causes of morbidity and mortality worldwide. As advancements in radiation therapy (RT) have significantly increased the number of cancer survivors, the risk of radiation-induced cardiovascular disease (RICD) in this group is a growing concern. Recent epidemiological data suggest that accidental or occupational exposure to low dose radiation, in addition to therapeutic ionizing radiation, can result in cardiovascular complications. The progression of radiation-induced cardiotoxicity often takes years to manifest but is also multifaceted, as the heart may be affected by a variety of pathologies. The risk of cardiovascular disease development in RT cancer survivors has been known for 40 years and several risk factors have been identified in the last two decades. However, most of the early work focused on clinical symptoms and manifestations, rather than understanding cellular processes regulating homeostatic processes of the cardiovascular system in response to radiation. Recent studies have suggested that a different approach may be needed to refute the risk of cardiovascular disease following radiation exposure. In this review, we will focus on how different radiation types and doses may induce cardiovascular complications, highlighting clinical manifestations and the mechanisms involved in the pathophysiology of radiation-induced cardiotoxicity. We will finally discuss how current and future research on heart development and homeostasis can help reduce the incidence of RICD.

  19. Radiation: Doses, Effects, Risks.

    ERIC Educational Resources Information Center

    Lean, Geoffrey, Ed.

    Few scientific issues arouse as much public controversy as the effects of radiation. This booklet is an attempt to summarize what is known about radiation and provide a basis for further discussion and debate. The first four chapters of the booklet are based on the most recent reports to the United Nations' General Assembly by the United Nations…

  20. Mechanistic and quantitative studies of bystander response in 3D tissues for low-dose radiation risk estimations

    SciTech Connect

    Amundson, Sally A.

    2013-06-12

    We have used the MatTek 3-dimensional human skin model to study the gene expression response of a 3D model to low and high dose low LET radiation, and to study the radiation bystander effect as a function of distance from the site of irradiation with either alpha particles or low LET protons. We have found response pathways that appear to be specific for low dose exposures, that could not have been predicted from high dose studies. We also report the time and distance dependent expression of a large number of genes in bystander tissue. the bystander response in 3D tissues showed many similarities to that described previously in 2D cultured cells, but also showed some differences.

  1. Radiation cancer analysis and low dose risk estimation: new developments and perspectives - conference to be held Feb 2002. Final technical report for period November 1, 2001--October 31, 2002

    SciTech Connect

    Brugmans, M.J.P.; Leenhouts, H.P.

    2002-10-01

    The Proceedings of the 20th LH Gray Conference on Radiation Cancer Analysis and Low Dose Risk Estimation: New Developments and Perspectives (17-21 February 2002, Ede, the Netherlands) comprises 32 peer-reviewed papers on invited and proffered contributions to the conference with a preface by the guest editors. The on-going discussion of low dose radiation risk; the issue of the linear, non-threshold extrapolation; and the anticipated new recommendations, e.g. from BEIR and ICRP, provided the back-drop for the conference. The meeting dealt with topics such as basic mechanisms and bystander effects, cancer modeling, cancer genetics, radon exposure and lung cancer risk, cancer after medical exposure, cancer risk estimation, dose-effect relationships, and application to radiation protection.

  2. Estimating potential evapotranspiration with improved radiation estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potential evapotranspiration (PET) is of great importance to estimation of surface energy budget and water balance calculation. The accurate estimation of PET will facilitate efficient irrigation scheduling, drainage design, and other agricultural and meteorological applications. However, accuracy o...

  3. Estimating Terrorism Risk

    DTIC Science & Technology

    2005-01-01

    preparedness by addressing unique planning, equipment, training, and exercise needs of large urban areas (DHS, 2004). Al- though there appears to be agreement ...reasonable minimum standards for community preparedness. Until these questions are answered, allocating home- land security resources based on risk is the...and threats are correlated with population density. There are practical benefits for using simple risk indicators such as those based upon population

  4. Radiation risks for patients having X rays

    SciTech Connect

    Hale, J.; Thomas, J.W.

    1985-12-01

    In addition to radiation from naturally occurring radioactive materials and cosmic rays, individuals in developed countries receive radiation doses to bone marrow and gonads from the medical diagnostic use of X rays. A brief discussion of radiation epidemiology shows that deleterious effects are low even when doses are high. The concept of acceptable risk is introduced to help evaluate the small, but still existent, risks of radiation dose. Examples of bone marrow and gonadal doses for representative X-ray examinations are presented along with the current best estimates, per unit of X-ray dose, of the induction of leukemia or of genetic harm. The risk to the patient from an examination can then be compared with the normal risk of mortality from leukemia or of the occurrence of genetic defects. The risk increase is found to be very low. The risks to unborn children from radiographic examinations are also discussed. The benefit to the patient from information obtained from the examination must be balanced against the small risks.

  5. [Medical insurance estimation of risks].

    PubMed

    Dunér, H

    1975-11-01

    The purpose of insurance medicine is to make a prognostic estimate of medical risk-factors in persons who apply for life, health, or accident insurance. Established risk-groups with a calculated average mortality and morbidity form the basis for premium rates and insurance terms. In most cases the applicant is accepted for insurance after a self-assessment of his health. Only around one per cent of the applications are refused, but there are cases in which the premium is raised, temporarily or permanently. It is often a matter of rough estimate, since the knowlege of the long-term prognosis for many diseases is incomplete. The insurance companies' rules for estimate of risk are revised at intervals of three or four years. The estimate of risk as regards life insurance has been gradually liberalised, while the medical conditions for health insurance have become stricter owing to an increase in the claims rate.

  6. Estimating shortwave solar radiation using net radiation and meteorological measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shortwave radiation has a wide variety of uses in land-atmosphere interactions research. Actual evapotranspiration estimation that involves stomatal conductance models like Jarvis and Ball-Berry require shortwave radiation to estimate photon flux density. However, in most weather stations, shortwave...

  7. [Dose loads on and radiation risk values for cosmonauts on a mission to Mars estimated from actual Martian vehicle engineering development].

    PubMed

    Shafirkin, A V; Kolomenskiĭ, A V; Mitrikas, V G; Petrov, V M

    2010-01-01

    The current design philosophy of a Mars orbiting vehicle, takeoff and landing systems and the transport return vehicle was taken into consideration for calculating the equivalent doses imparted to cosmonaut's organs and tissues by galactic cosmic rays, solar rays and the Earth's radiation belts, values of the total radiation risk over the lifespan following the mission and over the whole career period, and possible shortening of life expectancy. There are a number of uncertainties that should be evaluated, and radiation limits specified before setting off to Mars.

  8. Estimating solar radiation for plant simulation models

    NASA Technical Reports Server (NTRS)

    Hodges, T.; French, V.; Leduc, S.

    1985-01-01

    Five algorithms producing daily solar radiation surrogates using daily temperatures and rainfall were evaluated using measured solar radiation data for seven U.S. locations. The algorithms were compared both in terms of accuracy of daily solar radiation estimates and terms of response when used in a plant growth simulation model (CERES-wheat). Requirements for accuracy of solar radiation for plant growth simulation models are discussed. One algorithm is recommended as being best suited for use in these models when neither measured nor satellite estimated solar radiation values are available.

  9. Evidence Report: Risk of Radiation Carcinogenesis

    NASA Technical Reports Server (NTRS)

    Huff, Janice; Carnell, Lisa; Blattnig, Steve; Chappell, Lori; Kerry, George; Lumpkins, Sarah; Simonsen, Lisa; Slaba, Tony; Werneth, Charles

    2016-01-01

    As noted by Durante and Cucinotta (2008), cancer risk caused by exposure to space radiation is now generally considered a main hindrance to interplanetary travel for the following reasons: large uncertainties are associated with the projected cancer risk estimates; no simple and effective countermeasures are available, and significant uncertainties prevent scientists from determining the effectiveness of countermeasures. Optimizing operational parameters such as the length of space missions, crew selection for age and sex, or applying mitigation measures such as radiation shielding or use of biological countermeasures can be used to reduce risk, but these procedures have inherent limitations and are clouded by uncertainties. Space radiation is comprised of high energy protons, neutrons and high charge (Z) and energy (E) nuclei (HZE). The ionization patterns and resulting biological insults of these particles in molecules, cells, and tissues are distinct from typical terrestrial radiation, which is largely X-rays and gamma-rays, and generally characterized as low linear energy transfer (LET) radiation. Galactic cosmic rays (GCR) are comprised mostly of highly energetic protons with a small component of high charge and energy (HZE) nuclei. Prominent HZE nuclei include He, C, O, Ne, Mg, Si, and Fe. GCR ions have median energies near 1 GeV/n, and energies as high as 10 GeV/n make important contributions to the total exposure. Ionizing radiation is a well known carcinogen on Earth (BEIR 2006). The risks of cancer from X-rays and gamma-rays have been established at doses above 50 mSv (5 rem), although there are important uncertainties and on-going scientific debate about cancer risk at lower doses and at low dose rates (<50 mSv/h). The relationship between the early biological effects of HZE nuclei and the probability of cancer in humans is poorly understood, and it is this missing knowledge that leads to significant uncertainties in projecting cancer risks during space

  10. Ionizing Radiation Environments and Exposure Risks

    NASA Astrophysics Data System (ADS)

    Kim, M. H. Y.

    2015-12-01

    Space radiation environments for historically large solar particle events (SPE) and galactic cosmic rays (GCR) are simulated to characterize exposures to radio-sensitive organs for missions to low-Earth orbit (LEO), moon, near-Earth asteroid, and Mars. Primary and secondary particles for SPE and GCR are transported through the respective atmospheres of Earth or Mars, space vehicle, and astronaut's body tissues using NASA's HZETRN/QMSFRG computer code. Space radiation protection methods, which are derived largely from ground-based methods recommended by the National Council on Radiation Protection and Measurements (NCRP) or International Commission on Radiological Protections (ICRP), are built on the principles of risk justification, limitation, and ALARA (as low as reasonably achievable). However, because of the large uncertainties in high charge and energy (HZE) particle radiobiology and the small population of space crews, NASA develops distinct methods to implement a space radiation protection program. For the fatal cancer risks, which have been considered the dominant risk for GCR, the NASA Space Cancer Risk (NSCR) model has been developed from recommendations by NCRP; and undergone external review by the National Research Council (NRC), NCRP, and through peer-review publications. The NSCR model uses GCR environmental models, particle transport codes describing the GCR modification by atomic and nuclear interactions in atmospheric shielding coupled with spacecraft and tissue shielding, and NASA-defined quality factors for solid cancer and leukemia risk estimates for HZE particles. By implementing the NSCR model, the exposure risks from various heliospheric conditions are assessed for the radiation environments for various-class mission types to understand architectures and strategies of human exploration missions and ultimately to contribute to the optimization of radiation safety and well-being of space crewmembers participating in long-term space missions.

  11. Radiation: What determines the risk?

    SciTech Connect

    Mitchel, R.E.J.; Trivedi, A. ||

    1993-12-31

    Radiation, like other DNA damaging agents, can initiate a series of cellular events responsible for cancer development. However, in any individual the risk of cancer arising from a carcinogen exposure is variable, and is not a fixed value dependent only on the dose of carcinogen. This variability in overall risk arises from variability in the probabilities of the intermediate steps of the multistep processes of carcinogenesis. Using cellular and animal model systems, we have shown that deliberate manipulation of these biological processes is possible, and that the risk of cancer from a fixed exposure to a carcinogen can be made to increase or decrease. We have also shown that such changes in risk can result from intervention at times long before or after that carcinogen exposure. These results indicate that the principles of radiation protection can be expanded. We suggest that in addition to offering protection against exposure, radiation protection can include the development of strategies for protection against the ultimate biological consequences of an exposure. Improved understanding of the biology of radiation responses may lead to techniques for deliberate intervention that could be particularly useful in long duration manned space flight.

  12. Estimating risks of perinatal death.

    PubMed

    Smith, Gordon C S

    2005-01-01

    The relative and absolute risks of perinatal death that are estimated from observational studies are used frequently in counseling about obstetric intervention. The statistical basis for these estimates therefore is crucial, but many studies are seriously flawed. In this review, a number of aspects of the approach to the estimation of the risk of perinatal death are addressed. Key factors in the analysis include (1) the definition of the cause of the death, (2) differentiation between antepartum and intrapartum events, (3) the use of the appropriate denominator for the given cause of death, (4) the assessment of the cumulative risk where appropriate, (5) the use of appropriate statistical tests, (6) the stratification of analysis of delivery-related deaths by gestational age, and (7) the specific features of multiple pregnancy, which include the correct determination of the timing of antepartum stillbirth and the use of paired statistical tests when outcomes are compared in relation to the birth order of twin pairs.

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

    PubMed

    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.

  14. Risk estimation using probability machines

    PubMed Central

    2014-01-01

    Background Logistic regression has been the de facto, and often the only, model used in the description and analysis of relationships between a binary outcome and observed features. It is widely used to obtain the conditional probabilities of the outcome given predictors, as well as predictor effect size estimates using conditional odds ratios. Results We show how statistical learning machines for binary outcomes, provably consistent for the nonparametric regression problem, can be used to provide both consistent conditional probability estimation and conditional effect size estimates. Effect size estimates from learning machines leverage our understanding of counterfactual arguments central to the interpretation of such estimates. We show that, if the data generating model is logistic, we can recover accurate probability predictions and effect size estimates with nearly the same efficiency as a correct logistic model, both for main effects and interactions. We also propose a method using learning machines to scan for possible interaction effects quickly and efficiently. Simulations using random forest probability machines are presented. Conclusions The models we propose make no assumptions about the data structure, and capture the patterns in the data by just specifying the predictors involved and not any particular model structure. So they do not run the same risks of model mis-specification and the resultant estimation biases as a logistic model. This methodology, which we call a “risk machine”, will share properties from the statistical machine that it is derived from. PMID:24581306

  15. [Use of ionizing radiation sources in metallurgy: risk assessment].

    PubMed

    Giugni, U

    2012-01-01

    Use of ionizing radiation sources in the metallurgical industry: risk assessment. Radioactive sources and fixed or mobile X-ray equipment are used for both process and quality control. The use of ionizing radiation sources requires careful risk assessment. The text lists the characteristics of the sources and the legal requirements, and contains a description of the documentation required and the methods used for risk assessment. It describes how to estimate the doses to operators and the relevant classification criteria used for the purpose of radiation protection. Training programs must be organized in close collaboration between the radiation protection expert and the occupational physician.

  16. Comparison of genotoxic potency of styrene 7,8-oxide with gamma radiation and human cancer risk estimation of styrene using the rad-equivalence approach.

    PubMed

    Godderis, Lode; Aka, P; Kirsch-Volders, M; Veulemans, H

    2007-05-01

    Styrene is suspected to cause lympho-hematopoietic malignancies through the formation of styrene 7,8-oxide. However, we are still unable to calculate the cancer risk for workers exposed to styrene using epidemiological data. The aims of this study were to determine the blood dose after styrene exposure and to compare the genotoxic potency of styrene 7,8-oxide and gamma radiation in order to calculate the cancer risk by means of the rad-equivalence approach. Leucocytes of 20 individuals were exposed to 0, 0.1, 0.2 or 0.3 mM styrene 7,8-oxide (1 h) or 1, 2 or 3 gray (=100, 200, 300 rad) gamma radiation. Genotoxicity was evaluated with the cytokinesis-block micronucleus assay. Comparison of the two slopes of the regression lines between micronuclei and dose revealed a genotoxic potency for styrene 7,8-oxide of 37 rad/mMh, corresponding with a median value derived from mutagenicity studies (1, 37, 208 rad/mMh). At exposure levels of 1 ppm styrene, a blood styrene 7,8-oxide concentration between 0.03 x 10(-)(6) and 0.42 x 10(-)(6) mM is to be expected using data of toxicokinetic models and human exposure studies. With the cancer risk per unit dose of gamma radiation as benchmark, we calculated a lifetime risk of acquiring a fatal lympho-hematopoietic cancer of 0.17 in 10(3) workers (between 0.037 x 10(-)(3) and 5.0 x 10(-)(3)) exposed to 20 ppm styrene during 40 years.

  17. A New View of Radiation-Induced Cancer: Integrating Short- and Long-Term Processes. Part II: Second Cancer Risk Estimation

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    As the number of cancer survivors grows, prediction of radiotherapy-induced second cancer risks becomes increasingly important. Because the latency period for solid tumors is long, the risks of recently introduced radiotherapy protocols are not yet directly measurable. In the accompanying article, we presented a new biologically based mathematical model, which, in principle, can estimate second cancer risks for any protocol. The novelty of the model is that it integrates, into a single formalism, mechanistic analyses of pre-malignant cell dynamics on two different time scales: short-term during radiotherapy and recovery; long-term during the entire life span. Here, we apply the model to nine solid cancer types (stomach, lung, colon, rectal, pancreatic, bladder, breast, central nervous system, and thyroid) using data on radiotherapy-induced second malignancies, on Japanese atomic bomb survivors, and on background US cancer incidence. Potentially, the model can be incorporated into radiotherapy treatment planning algorithms, adding second cancer risk as an optimization criterion.

  18. Minimizing and communicating radiation risk in pediatric nuclear medicine.

    PubMed

    Fahey, Frederic H; Treves, S Ted; Adelstein, S James

    2011-08-01

    The value of pediatric nuclear medicine is well established. Pediatric patients are referred to nuclear medicine from nearly all pediatric specialties including urology, oncology, cardiology, gastroenterology, and orthopedics. Radiation exposure is associated with a potential, small, risk of inducing cancer in the patient later in life and is higher in younger patients. Recently, there has been enhanced interest in exposure to radiation from medical imaging. Thus, it is incumbent on practitioners of pediatric nuclear medicine to have an understanding of dosimetry and radiation risk to communicate effectively with their patients and their families. This article reviews radiation dosimetry for radiopharmaceuticals and also CT given the recent proliferation of PET/CT and SPECT/CT. It also describes the scientific basis for radiation risk estimation in the context of pediatric nuclear medicine. Approaches for effective communication of risk to patients' families are discussed. Lastly, radiation dose reduction in pediatric nuclear medicine is explicated.

  19. Minimizing and communicating radiation risk in pediatric nuclear medicine.

    PubMed

    Fahey, Frederic H; Treves, S Ted; Adelstein, S James

    2012-03-01

    The value of pediatric nuclear medicine is well established. Pediatric patients are referred to nuclear medicine from nearly all pediatric specialties including urology, oncology, cardiology, gastroenterology, and orthopedics. Radiation exposure is associated with a potential, small, risk of inducing cancer in the patient later in life and is higher in younger patients. Recently, there has been enhanced interest in exposure to radiation from medical imaging. Thus, it is incumbent on practitioners of pediatric nuclear medicine to have an understanding of dosimetry and radiation risk to communicate effectively with their patients and their families. This article reviews radiation dosimetry for radiopharmaceuticals and also CT given the recent proliferation of PET/CT and SPECT/CT. It also describes the scientific basis for radiation risk estimation in the context of pediatric nuclear medicine. Approaches for effective communication of risk to patients' families are discussed. Lastly, radiation dose reduction in pediatric nuclear medicine is explicated.

  20. Box model of radionuclide dispersion and radiation risk estimation for population in case of radioactivity release from nuclear submarine {number_sign}601 dumped in the Kara Sea

    SciTech Connect

    Yefimov, E.I.; Pankratov, D.V.; Ignatiev, S.V.

    1997-12-31

    When ships with nuclear reactors or nuclear materials aboard suffer shipwreck or in the case of burial or dumping of radioactive wastes, atmospheric fallout, etc., radionuclides may be released and spread in the sea, contaminating the sea water and the sea bottom. When a nuclear submarine (NS) is dumped this spread of activity may occur due to gradual core destruction by corrosion over many years. The objective of this paper is to develop a mathematical model of radionuclide dispersion and to assess the population dose and radiation risk for radionuclide release from the NS No. 601, with Pb-Bi coolant that was dumped in the Kara Sea.

  1. Biological Bases of Space Radiation Risk

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session JP4, the discussion focuses on the following topics: Hematopoiesis Dynamics in Irradiated Mammals, Mathematical Modeling; Estimating Health Risks in Space from Galactic Cosmic Rays; Failure of Heavy Ions to Affect Physiological Integrity of the Corneal Endothelial Monolayer; Application of an Unbiased Two-Gel CDNA Library Screening Method to Expression Monitoring of Genes in Irradiated Versus Control Cells; Detection of Radiation-Induced DNA Strand Breaks in Mammalian Cells By Enzymatic Post-Labeling; Evaluation of Bleomycin-Induced Chromosome Aberrations Under Microgravity Conditions in Human Lymphocytes, Using "Fish" Techniques; Technical Description of the Space Exposure Biology Assembly Seba on ISS; and Cytogenetic Research in Biological Dosimetry.

  2. A Model to Estimate the Risk of Breast Cancer-Related Lymphedema: Combinations of Treatment-Related Factors of the Number of Dissected Axillary Nodes, Adjuvant Chemotherapy, and Radiation Therapy

    SciTech Connect

    Kim, Myungsoo; Kim, Seok Won; Lee, Sung Uk; Lee, Nam Kwon; Jung, So-Youn; Kim, Tae Hyun; Lee, Eun Sook; Kang, Han-Sung; Shin, Kyung Hwan

    2013-07-01

    Purpose: The development of breast cancer-related lymphedema (LE) is closely related to the number of dissected axillary lymph nodes (N-ALNs), chemotherapy, and radiation therapy. In this study, we attempted to estimate the risk of LE based on combinations of these treatment-related factors. Methods and Materials: A total of 772 patients with breast cancer, who underwent primary surgery with axillary lymph node dissection from 2004 to 2009, were retrospectively analyzed. Adjuvant chemotherapy (ACT) was performed in 677 patients (88%). Among patients who received radiation therapy (n=675), 274 (35%) received supraclavicular radiation therapy (SCRT). Results: At a median follow-up of 5.1 years (range, 3.0-8.3 years), 127 patients had developed LE. The overall 5-year cumulative incidence of LE was 17%. Among the 127 affected patients, LE occurred within 2 years after surgery in 97 (76%) and within 3 years in 115 (91%) patients. Multivariate analysis showed that N-ALN (hazard ratio [HR], 2.81; P<.001), ACT (HR, 4.14; P=.048), and SCRT (HR, 3.24; P<.001) were independent risk factors for LE. The total number of risk factors correlated well with the incidence of LE. Patients with no risk or 1 risk factor showed a significantly lower 5-year probability of LE (3%) than patients with 2 (19%) or 3 risk factors (38%) (P<.001). Conclusions: The risk factors associated with LE were N-ALN, ACT, and SCRT. A simple model using combinations of these factors may help clinicians predict the risk of LE.

  3. Evaluating Shielding Effectiveness for Reducing Space Radiation Cancer Risks

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Ren, Lei

    2007-01-01

    We discuss calculations of probability distribution functions (PDF) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPE). The PDF s are used in significance tests of the effectiveness of potential radiation shielding approaches. Uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments are considered in models of cancer risk PDF s. Competing mortality risks and functional correlations in radiation quality factor uncertainties are treated in the calculations. We show that the cancer risk uncertainty, defined as the ratio of the 95% confidence level (CL) to the point estimate is about 4-fold for lunar and Mars mission risk projections. For short-stay lunar missions (<180 d), SPE s present the most significant risk, however one that is mitigated effectively by shielding, especially for carbon composites structures with high hydrogen content. In contrast, for long duration lunar (>180 d) or Mars missions, GCR risks may exceed radiation risk limits, with 95% CL s exceeding 10% fatal risk for males and females on a Mars mission. For reducing GCR cancer risks, shielding materials are marginally effective because of the penetrating nature of GCR and secondary radiation produced in tissue by relativistic particles. At the present time, polyethylene or carbon composite shielding can not be shown to significantly reduce risk compared to aluminum shielding based on a significance test that accounts for radiobiology uncertainties in GCR risk projection.

  4. NASA Space Radiation Program Integrative Risk Model Toolkit

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Hu, Shaowen; Plante, Ianik; Ponomarev, Artem L.; Sandridge, Chris

    2015-01-01

    NASA Space Radiation Program Element scientists have been actively involved in development of an integrative risk models toolkit that includes models for acute radiation risk and organ dose projection (ARRBOD), NASA space radiation cancer risk projection (NSCR), hemocyte dose estimation (HemoDose), GCR event-based risk model code (GERMcode), and relativistic ion tracks (RITRACKS), NASA radiation track image (NASARTI), and the On-Line Tool for the Assessment of Radiation in Space (OLTARIS). This session will introduce the components of the risk toolkit with opportunity for hands on demonstrations. The brief descriptions of each tools are: ARRBOD for Organ dose projection and acute radiation risk calculation from exposure to solar particle event; NSCR for Projection of cancer risk from exposure to space radiation; HemoDose for retrospective dose estimation by using multi-type blood cell counts; GERMcode for basic physical and biophysical properties for an ion beam, and biophysical and radiobiological properties for a beam transport to the target in the NASA Space Radiation Laboratory beam line; RITRACKS for simulation of heavy ion and delta-ray track structure, radiation chemistry, DNA structure and DNA damage at the molecular scale; NASARTI for modeling of the effects of space radiation on human cells and tissue by incorporating a physical model of tracks, cell nucleus, and DNA damage foci with image segmentation for the automated count; and OLTARIS, an integrated tool set utilizing HZETRN (High Charge and Energy Transport) intended to help scientists and engineers study the effects of space radiation on shielding materials, electronics, and biological systems.

  5. Uncertainty of Calculated Risk Estimates for Secondary Malignancies After Radiotherapy

    SciTech Connect

    Kry, Stephen F. . E-mail: sfkry@mdanderson.org; Followill, David; White, R. Allen; Stovall, Marilyn; Kuban, Deborah A.; Salehpour, Mohammad

    2007-07-15

    Purpose: The significance of risk estimates for fatal secondary malignancies caused by out-of-field radiation exposure remains unresolved because the uncertainty in calculated risk estimates has not been established. This work examines the uncertainty in absolute risk estimates and in the ratio of risk estimates between different treatment modalities. Methods and Materials: Clinically reasonable out-of-field doses and calculated risk estimates were taken from the literature for several prostate treatment modalities, including intensity-modulated radiotherapy (IMRT), and were recalculated using the most recent risk model. The uncertainties in this risk model and uncertainties in the linearity of the dose-response model were considered in generating 90% confidence intervals for the uncertainty in the absolute risk estimates and in the ratio of the risk estimates. Results: The absolute risk estimates of fatal secondary malignancy were associated with very large uncertainties, which precluded distinctions between the risks associated with the different treatment modalities considered. However, a much smaller confidence interval exists for the ratio of risk estimates, and this ratio between different treatment modalities may be statistically significant when there is an effective dose equivalent difference of at least 50%. Such a difference may exist between clinically reasonable treatment options, including 6-MV IMRT versus 18-MV IMRT for prostate therapy. Conclusion: The ratio of the risk between different treatment modalities may be significantly different. Consequently risk models and associated risk estimates may be useful and meaningful for evaluating different treatment options. The calculated risk of secondary malignancy should be considered in the selection of an optimal treatment plan.

  6. Ionizing radiation risks to satellite power systems (SPS) workers

    SciTech Connect

    Lyman, J.T.; Ainsworth, E.J.; Alpen, E.L.; Bond, V.; Curtis, S.B.; Fry, R.J.M.; Jackson, K.L.; Nachtwey, S.; Sondhaus, C.; Tobias, C.A.; Fabrikant, J.I.

    1980-11-01

    The radiation risks to the health of workers who will construct and maintain solar power satellites in the space environment were examined. For ionizing radiation, the major concern will be late or delayed health effects, particularly the increased risk of radiation-induced cancer. The estimated lifetime risk for cancer is 0.8 to 5.0 excess deaths per 10,000 workers per rad of exposure. Thus, for example, in 10,000 workers who completed ten missions with an exposure of 40 rem per mission, 320 to 2000 additional deaths in excess of the 1640 deaths from normally occurring cancer, would be expected. These estimates would indicate a 20 to 120% increase in cancer deaths in the worker-population. The wide range in these estimates stems from the choice of the risk-projection model and the dose-response relationsip. The choice between a linear and a linear-quadratic dose-response model may alter the risk estimate by a factor of about two. The method of analysis (e.g., relative vs absolute risk model) can alter the risk estimate by an additional factor of three. Choosing different age and sex distributions can further change the estimate by another factor of up to three. The potential genetic consequences could be of significance, but at the present time, sufficient information on the age and sex distribution of the worker population is lacking for precise estimation of risk. The potential teratogenic consequences resulting from radiation are considered significant. Radiation exposure of a pregnant worker could result in developmental abnormalities.

  7. Medical radiation exposure and genetic risks

    SciTech Connect

    Baker, D.G.

    1980-09-01

    Everyone is exposed to background radiation throughout life (100 mrem/year to the gonads or 4 to 5 rem during the reproductive years). A lumbosacral series might deliver 2500 mrem to the male or 400 mrem to the female gonads. A radiologic procedure is a cost/benefit decision, and genetic risk is a part of the cost. Although cost is usually very low compared to benefit, if the procedure is unnecessary then the cost may be unacceptable. On the basis of current estimates, the doubling dose is assumed to be 40 rem (range 20 to 200) for an acute dose, and 100 rem for protracted exposure. Although there is no satisfactory way to predict the size of the risk for an individual exposed, any risk should be incentive to avoid unnecessary radiation to the gonads. Conception should be delayed for at least ten months for women and three or four months for men after irradiation of the gonads. The current incidence of genetically related diseases in the United States population is 60,000 per million live births. Based on the most conservative set of assumptions, an average gonadal dose of 1000 mrem to the whole population would increase the incidence of genetically related diseases by 0.2%.

  8. The assessment of risks from exposure to low-levels of ionizing radiation

    SciTech Connect

    Gilbert, E.S.

    1992-06-01

    This report is concerned with risk assessments for human populations receiving low level radiation doses; workers routinely exposed to radiation, Japanese victims of nuclear bombs, and the general public are all considered. Topics covered include risk estimates for cancer, mortality rates, risk estimates for nuclear site workers, and dosimetry.

  9. Radiation protection issues in galactic cosmic ray risk assessment

    NASA Technical Reports Server (NTRS)

    Sinclair, W. K.

    1994-01-01

    Radiation protection involves the limitation of exposure to below threshold doses for direct (or deterministic) effects and a knowledge of the risk of stochastic effects after low doses. The principal stochastic risk associated with low dose rate galactic cosmic rays is the increased risk of cancer. Estimates of this risk depend on two factors (a) estimates of cancer risk for low-LET radiation and (b) values of the appropriate radiation weighting factors, WR, for the high-LET radiations of galactic cosmic rays. Both factors are subject to considerable uncertainty. The low-LET cancer risk derived from the late effects of the atomic bombs is vulnerable to a number of uncertainties including especially that from projection in time, and from extrapolation from high to low dose rate. Nevertheless, recent low dose studies of workers and others tend to confirm these estimates. WR, relies on biological effects studied mainly in non-human systems. Additional laboratory studies could reduce the uncertainties in WR and thus produce a more confident estimate of the overall risk of galactic cosmic rays.

  10. Radiation protection issues in galactic cosmic ray risk assessment.

    PubMed

    Sinclair, W K

    1994-01-01

    Radiation protection involves the limitation of exposure to below threshold doses for direct (or deterministic) effects and a knowledge of the risk of stochastic effects after low doses. The principal stochastic risk associated with low dose rate galactic cosmic rays is the increased risk of cancer. Estimates of this risk depend on two factors (a) estimates of cancer risk for low-LET radiation and (b) values of the appropriate radiation weighting factors, WR, for the high-LET radiations of galactic cosmic rays. Both factors are subject to considerable uncertainty. The low-LET cancer risk derived from the late effects of the atomic bombs is vulnerable to a number of uncertainties including especially that from projection in time, and from extrapolation from high to low dose rate. Nevertheless, recent low dose studies of workers and others tend to confirm these estimates. WR, relies on biological effects studied mainly in non-human systems. Additional laboratory studies could reduce the uncertainties in WR and thus produce a more confident estimate of the overall risk of galactic cosmic rays.

  11. Instrumentation for investigation of the depth-dose distribution by the Liulin-5 instrument of a human phantom on the Russian segment of ISS for estimation of the radiation risk during long term space flights

    NASA Technical Reports Server (NTRS)

    Semkova, J.; Koleva, R.; Todorova, G.; Kanchev, N.; Petrov, V.; Shurshakov, V.; Tchhernykh, I.; Kireeva, S.

    2004-01-01

    Described is the Liulin-5 experiment and instrumentation, developed for investigation of the space radiation doses depth distribution in a human phantom on the Russian Segment of the International Space Station (ISS). Liulin-5 experiment is a part of the international project MATROSHKA-R on ISS. The experiment MATROSHKA-R is aimed to study the depth dose distribution at the sites of critical organs of the human body, using models of human body-anthropomorphic and spherical tissue-equivalent phantoms. The aim of Liulin-5 experiment is long term (4-5 years) investigation of the radiation environment dynamics inside the spherical tissue-equivalent phantom, mounted in different places of the Russian Segment of ISS. Energy deposition spectra, linear energy transfer spectra, flux and dose rates for protons and the biologically-relevant heavy ion components of the galactic cosmic radiation will be measured simultaneously with near real time resolution at different depths of the phantom by a telescope of silicon detectors. Data obtained together with data from other active and passive dosimeters will be used to estimate the radiation risk to the crewmembers, verify the models of radiation environment in low Earth orbit, validate body transport model and correlate organ level dose to skin dose. Presented are the test results of the prototype unit. The spherical phantom will be flown on the ISS in 2004 year and Liulin-5 experiment is planned for 2005 year. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  12. Instrumentation for investigation of the depth-dose distribution by the Liulin-5 instrument of a human phantom on the Russian segment of ISS for estimation of the radiation risk during long term space flights.

    PubMed

    Semkova, J; Koleva, R; Todorova, G; Kanchev, N; Petrov, V; Shurshakov, V; Tchhernykh, I; Kireeva, S

    2004-01-01

    Described is the Liulin-5 experiment and instrumentation, developed for investigation of the space radiation doses depth distribution in a human phantom on the Russian Segment of the International Space Station (ISS). Liulin-5 experiment is a part of the international project MATROSHKA-R on ISS. The experiment MATROSHKA-R is aimed to study the depth dose distribution at the sites of critical organs of the human body, using models of human body-anthropomorphic and spherical tissue-equivalent phantoms. The aim of Liulin-5 experiment is long term (4-5 years) investigation of the radiation environment dynamics inside the spherical tissue-equivalent phantom, mounted in different places of the Russian Segment of ISS. Energy deposition spectra, linear energy transfer spectra, flux and dose rates for protons and the biologically-relevant heavy ion components of the galactic cosmic radiation will be measured simultaneously with near real time resolution at different depths of the phantom by a telescope of silicon detectors. Data obtained together with data from other active and passive dosimeters will be used to estimate the radiation risk to the crewmembers, verify the models of radiation environment in low Earth orbit, validate body transport model and correlate organ level dose to skin dose. Presented are the test results of the prototype unit. The spherical phantom will be flown on the ISS in 2004 year and Liulin-5 experiment is planned for 2005 year.

  13. Radiation in medicine: Origins, risks and aspirations

    PubMed Central

    Donya, Mohamed; Radford, Mark; ElGuindy, Ahmed; Firmin, David; Yacoub, Magdi H.

    2014-01-01

    The use of radiation in medicine is now pervasive and routine. From their crude beginnings 100 years ago, diagnostic radiology, nuclear medicine and radiation therapy have all evolved into advanced techniques, and are regarded as essential tools across all branches and specialties of medicine. The inherent properties of ionizing radiation provide many benefits, but can also cause potential harm. Its use within medical practice thus involves an informed judgment regarding the risk/benefit ratio. This judgment requires not only medical knowledge, but also an understanding of radiation itself. This work provides a global perspective on radiation risks, exposure and mitigation strategies. PMID:25780797

  14. Estimated Radiation on Mars, Hits per Cell Nucleus

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This global map of Mars shows estimates for amounts of high-energy-particle cosmic radiation reaching the surface, a serious health concern for any future human exploration of the planet.

    The estimates are based on cosmic-radiation measurements made on the way to Mars by the Mars radiation environment experiment, an instrument on NASA's 2001 Mars Odyssey spacecraft, plus information about Mars' surface elevations from the laser altimeter instrument on NASA's Mars Global Surveyor. The areas of Mars expected to have least radiation are where elevation is lowest, because those areas have more atmosphere above them to block out some of the radiation. Earth's thick atmosphere shields us from most cosmic radiation, but Mars has a much thinner atmosphere than Earth does.

    Colors in the map refer to the estimated average number of times per year each cell nucleus in a human there would be hit by a high-energy cosmic ray particle. The range is generally from two hits (color-coded green), a moderate risk level, to eight hits (coded red), a high risk level.

    NASA's Jet Propulsion Laboratory, Pasadena, Calif. manages the 2001 Mars Odyssey and Mars Global Surveyor missions for NASA's Office of Space Science, Washington D.C. The Mars radiation environment experiment was developed by NASA's Johnson Space Center. Lockheed Martin Astronautics, Denver, is the prime contractor for Odyssey, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Probabilistic Assessment of Radiation Risk for Astronauts in Space Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; DeAngelis, Giovanni; Cucinotta, Francis A.

    2009-01-01

    Accurate predictions of the health risks to astronauts from space radiation exposure are necessary for enabling future lunar and Mars missions. Space radiation consists of solar particle events (SPEs), comprised largely of medium energy protons, (less than 100 MeV); and galactic cosmic rays (GCR), which include protons and heavy ions of higher energies. While the expected frequency of SPEs is strongly influenced by the solar activity cycle, SPE occurrences themselves are random in nature. A solar modulation model has been developed for the temporal characterization of the GCR environment, which is represented by the deceleration potential, phi. The risk of radiation exposure from SPEs during extra-vehicular activities (EVAs) or in lightly shielded vehicles is a major concern for radiation protection, including determining the shielding and operational requirements for astronauts and hardware. To support the probabilistic risk assessment for EVAs, which would be up to 15% of crew time on lunar missions, we estimated the probability of SPE occurrence as a function of time within a solar cycle using a nonhomogeneous Poisson model to fit the historical database of measurements of protons with energy > 30 MeV, (phi)30. The resultant organ doses and dose equivalents, as well as effective whole body doses for acute and cancer risk estimations are analyzed for a conceptual habitat module and a lunar rover during defined space mission periods. This probabilistic approach to radiation risk assessment from SPE and GCR is in support of mission design and operational planning to manage radiation risks for space exploration.

  16. Regional estimates of radiated seismic energy

    USGS Publications Warehouse

    Boatwright, J.; Choy, G.L.; Seekins, L.C.

    2002-01-01

    We revise the spectral technique for estimating radiated energy from recordings of large earthquakes at regional distances (?? 27.5 km from the source, we model the geometrical spreading of the regional wavefield as r-?? where???? = 0.5 for f ??? 0.2 Hz and ?? = 0.7 for f ??? 0.25 Hz. We fit the spectral falloff with distance using a frequency-dependent attenuation Q = 400(f/1.5)0.6, where Q = 400 for f ??? 1.5 Hz. There is little directivity apparent in the corrected velocity spectra: the velocity spectra observed to the northwest along strike are amplified by a factor of 2.5 from 0.3 to 1.0 Hz and those to the southeast are amplified by a factor of 1.6 from 0.3 to 0.7 Hz. We group the stations in NEHRP site classes, using average 1-D velocity structures to estimate site amplification as a function of frequency and assuming 0.40 ??? ?? ??? 0.55 sec for the near-surface attenuation. We increase the amplification of the soft-soil sites from 0.1 to 1.0 Hz by a factor that reaches 1.7 at 0.3 Hz because they are more strongly amplified than the NEHRP-D velocity structure predicts. We combine the 65 single-station estimates of radiated energy using an equal-azimuth weighting scheme that compensates for station distribution and incorporates the observed directivity, yielding a regional estimate of Es = 3.4 ?? 0.7 ?? 1022 dyne cm. This regional estimate of radiated energy corresponds closely to the teleseismic estimate of Es = 3.2 ?? 1022 dyne cm.

  17. Estimated radiation dose from timepieces containing tritium

    SciTech Connect

    McDowell-Boyer, L M

    1980-01-01

    Luminescent timepieces containing radioactive tritium, either in elemental form or incorporated into paint, are available to the general public. The purpose of this study was to estimate potential radiation dose commitments received by the public annually as a result of exposure to tritium which may escape from the timepieces during their distribution, use, repair, and disposal. Much uncertainty is associated with final dose estimates due to limitations of empirical data from which exposure parameters were derived. Maximum individual dose estimates were generally less than 3 ..mu..Sv/yr, but ranged up to 2 mSv under worst-case conditions postulated. Estimated annual collective (population) doses were less than 5 person/Sv per million timepieces distributed.

  18. Risk of Skin Cancer from Space Radiation. Chapter 11

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; George, Kerry A.; Wu, Hong-Lu

    2003-01-01

    We review the methods for estimating the probability of increased incidence of skin cancers from space radiation exposure, and describe some of the individual factors that may contribute to risk projection models, including skin pigment, and synergistic effects of combined ionizing and UV exposure. The steep dose gradients from trapped electrons, protons, and heavy ions radiation during EVA and limitations in EVA dosimetry are important factors for projecting skin cancer risk of astronauts. We estimate that the probability of increased skin cancer risk varies more than 10-fold for individual astronauts and that the risk of skin cancer could exceed 1 % for future lunar base operations for astronauts with light skin color and hair. Limitations in physical dosimetry in estimating the distribution of dose at the skin suggest that new biodosimetry methods be developed for responding to accidental overexposure of the skin during future space missions.

  19. Evaluations of Risks from the Lunar and Mars Radiation Environments

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Hayat, Matthew J.; Feiveson, Alan H.; Cucinotta, Francis A.

    2008-01-01

    Protecting astronauts from the space radiation environments requires accurate projections of radiation in future space missions. Characterization of the ionizing radiation environment is challenging because the interplanetary plasma and radiation fields are modulated by solar disturbances and the radiation doses received by astronauts in interplanetary space are likewise influenced. The galactic cosmic radiation (GCR) flux for the next solar cycle was estimated as a function of interplanetary deceleration potential, which has been derived from GCR flux and Climax neutron monitor rate measurements over the last 4 decades. For the chaotic nature of solar particle event (SPE) occurrence, the mean frequency of SPE at any given proton fluence threshold during a defined mission duration was obtained from a Poisson process model using proton fluence measurements of SPEs during the past 5 solar cycles (19-23). Analytic energy spectra of 34 historically large SPEs were constructed over broad energy ranges extending to GeV. Using an integrated space radiation model (which includes the transport codes HZETRN [1] and BRYNTRN [2], and the quantum nuclear interaction model QMSFRG[3]), the propagation and interaction properties of the energetic nucleons through various media were predicted. Risk assessment from GCR and SPE was evaluated at the specific organs inside a typical spacecraft using CAM [4] model. The representative risk level at each event size and their standard deviation were obtained from the analysis of 34 SPEs. Risks from different event sizes and their frequency of occurrences in a specified mission period were evaluated for the concern of acute health effects especially during extra-vehicular activities (EVA). The results will be useful for the development of an integrated strategy of optimizing radiation protection on the lunar and Mars missions. Keywords: Space Radiation Environments; Galactic Cosmic Radiation; Solar Particle Event; Radiation Risk; Risk

  20. Estimating cancer risks to adults undergoing body CT examinations.

    PubMed

    Huda, Walter; He, Wenjun

    2012-06-01

    The purpose of the study is to estimate cancer risks from the amount of radiation used to perform body computed tomography (CT) examination. The ImPACT CT Patient Dosimetry Calculator was used to compute values of organ doses for adult body CT examinations. The radiation used to perform each examination was quantified by the dose-length product (DLP). Patient organ doses were converted into corresponding age and sex dependent cancer risks using data from BEIR VII. Results are presented for cancer risks per unit DLP and unit effective dose for 11 sensitive organs, as well as estimates of the contribution from 'other organs'. For patients who differ from a standard sized adult, correction factors based on the patient weight and antero-posterior dimension are provided to adjust organ doses and the corresponding risks. At constant incident radiation intensity, for CT examinations that include the chest, risks for females are markedly higher than those for males, whereas for examinations that include the pelvis, risks in males were slightly higher than those in females. In abdominal CT scans, risks for males and female patients are very similar. For abdominal CT scans, increasing the patient age from 20 to 80 resulted in a reduction in patient risks of nearly a factor of 5. The average cancer risk for chest/abdomen/pelvis CT examinations was ∼26 % higher than the cancer risk caused by 'sensitive organs'. Doses and radiation risks in 80 kg adults were ∼10 % lower than those in 70 kg patients. Cancer risks in body CT can be estimated from the examination DLP by accounting for sex, age, as well as patient physical characteristics.

  1. Radiation Protection for Manned Interplanetary Missions - Radiation Sources, Risks, Remedies

    NASA Astrophysics Data System (ADS)

    Facius, R.; Reitz, G.

    Health risks in interplanetary explorative missions differ in two major features significantly from those during the manned missions experienced so far. For one, presently available technologies lead to durations of such missions significantly longer than so far encountered - with the added complication that emergency returns are ruled out. Thus radiation exposures and hence risks for late radiation sequelae like cancer increase proportional to mission duration - similar like most other health and many technical risks too. Secondly, loss of the geomagnetic shielding available in low earth orbits (LEO) does increase the radiation dose rates from galactic cosmic rays (GCR) since significant fractions of the GCR flux below about 10 GeV/n now can reach the space vehicle. In addition, radiation from solar particle events (SPE) which at most in polar orbit segments can contribute to the radiation exposure during LEO missions now can reach the spaceship unattenuated. Radiation doses from extreme SPEs can reach levels where even early acute radiation sickness might ensue - with the added risks from potentially associated crew performance decrements. In contrast to the by and large predictable GCR contribution, the doses and hence risks from large SPEs can only stochastically be assessed. Mission designers face the task to contain the overall health risk within acceptable limits. Towards this end they have to transport the particle fluxes of the radiation fields in free space through the walls of the spaceship and through the tissue of the astronaut to the radiation sensitive organs. To obtain a quantity which is useful for risk assessment, the radiobiological effectiveness as well as the specific sensitivity of a given organ has to be accounted for in such transport calculations which of course require a detailed knowledge of the spatial distribution and the atomic composition of the surrounding shielding material. In doing so the mission designer encounters two major

  2. Factors that modify risks of radiation-induced cancer

    SciTech Connect

    Fabrikant, J.I.

    1988-11-01

    The collective influence of biologic and physical factors that modify risks of radiation-induced cancer introduces uncertainties sufficient to deny precision of estimates of human cancer risk that can be calculated for low-dose radiation in exposed populations. The important biologic characteristics include the tissue sites and cell types, baseline cancer incidence, minimum latent period, time-to-tumor recognition, and the influence of individual host (age and sex) and competing etiologic influences. Physical factors include radiation dose, dose rate, and radiation quality. Statistical factors include time-response projection models, risk coefficients, and dose-response relationships. Other modifying factors include other carcinogens, and other biological sources (hormonal status, immune status, hereditary factors).

  3. Radiation Risk Assessment of the Individual Astronaut: A Complement to Radiation Interests at the NIH

    NASA Technical Reports Server (NTRS)

    Richmond, Robert C.

    2004-01-01

    Predicting human risks following exposure to space radiation is uncertain in part because of unpredictable distribution of high-LET and low-dose-derived damage amongst cells in tissues, unknown synergistic effects of microgravity upon gene- and protein-expression, and inadequately modeled processing of radiation-induced damage within cells to produce rare and late-appearing malignant cancers. Furthermore, estimation of risks of radiogenic outcome within small numbers of astronauts is not possible using classic epidemiologic study. It therefore seems useful to develop strategies of risk-assessment based upon large datasets acquired from correlated biological models useful for resolving radiogenic risk-assessment for irradiated individuals. In this regard, it is suggested that sensitive cellular biodosimeters that simultaneously report 1) the quantity of absorbed dose after exposure to ionizing radiation, 2) the quality of radiation delivering that dose, and 3) the biomolecular risk of malignant transformation be developed in order to resolve these NASA-specific challenges. Multiparametric cellular biodosimeters could be developed using analyses of gene-expression and protein-expression whereby large datasets of cellular response to radiation-induced damage are analyzed for markers predictive for acute response as well as cancer-risk. A new paradigm is accordingly addressed wherein genomic and proteomic datasets are registered and interrogated in order to provide statistically significant dose-dependent risk estimation in individual astronauts. This evaluation of the individual for assessment of radiogenic outcomes connects to NIH program in that such a paradigm also supports assignment of a given patient to a specific therapy, the diagnosis of response of that patient to therapy, and the prediction of risks accumulated by that patient during therapy - such as risks incurred by scatter and neutrons produced during high-energy Intensity-Modulated Radiation Therapy

  4. Estimating radiated energy for complex volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Fry, B.; Jolly, A. D.; Ristau, J. P.

    2013-12-01

    The August 6th, 2012 Te Maari eruption in the Tongariro National Park included a complex sequence of activity including a pre-eruption debris avalanche and at least three distinct eruptive pulses. In such a scenario, classic seismic methods such as moment tensor inversion struggle to characterize the whole event due to overlapping coda of the disparate bursts. To understand the entire eruption in terms of energy budget, we determine the trace energy density according to the more general formulations of Kanamori (1977) and Vassiliou and Kanamori (1982). By calculating the broad-band integral of the energy spectrum, we quantify radiated energy from the eruption cycle for each component at 3-component seismic monitoring sites surrounding the volcano and compare these results to observations at mid- and far-field distances. We correct for anelastic attenuation, noting that the solution is relatively insensitive to this correction as the records are essentially within the near-field. This suggests that even near to the source, most of the radiated energy is contained in relatively low frequencies which are less attenuated at short propagation distances. In the double-couple case of earthquakes (for which the method was originally developed), difficulties arise in situations with poor azimuthal data coverage. This is because the energy recorded at a single station is largely influenced by heterogeneous radiation patterns. For the volcano case, volumetric excitations of unknown source geometries may produce similar heterogeneities, which can be averaged by incorporation of well-distributed data. Our results provide estimates of radiated energy (Es) from the sequence ranging from 2.96 x 10^9 to 2.58 X 10^10 N*m, corresponding to an average energy magnitude of Me=3.72. This estimate is significantly lower than the predicted energy release based on an independently calculated moment tensor inversion. Preliminary results suggest that routine full-waveform energy calculations

  5. Space Radiation Cancer Risk Projections and Uncertainties - 2010

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Chappell, Lori J.

    2011-01-01

    Uncertainties in estimating health risks from galactic cosmic rays greatly limit space mission lengths and potential risk mitigation evaluations. NASA limits astronaut exposures to a 3% risk of exposure-induced death and protects against uncertainties using an assessment of 95% confidence intervals in the projection model. Revisions to this model for lifetime cancer risks from space radiation and new estimates of model uncertainties are described here. We review models of space environments and transport code predictions of organ exposures, and characterize uncertainties in these descriptions. We summarize recent analysis of low linear energy transfer radio-epidemiology data, including revision to Japanese A-bomb survivor dosimetry, longer follow-up of exposed cohorts, and reassessments of dose and dose-rate reduction effectiveness factors. We compare these projections and uncertainties with earlier estimates. Current understanding of radiation quality effects and recent data on factors of relative biological effectiveness and particle track structure are reviewed. Recent radiobiology experiment results provide new information on solid cancer and leukemia risks from heavy ions. We also consider deviations from the paradigm of linearity at low doses of heavy ions motivated by non-targeted effects models. New findings and knowledge are used to revise the NASA risk projection model for space radiation cancer risks.

  6. Risk cross sections and their application to risk estimation in the galactic cosmic-ray environment

    NASA Technical Reports Server (NTRS)

    Curtis, S. B.; Nealy, J. E.; Wilson, J. W.; Chatterjee, A. (Principal Investigator)

    1995-01-01

    Radiation risk cross sections (i.e. risks per particle fluence) are discussed in the context of estimating the risk of radiation-induced cancer on long-term space flights from the galactic cosmic radiation outside the confines of the earth's magnetic field. Such quantities are useful for handling effects not seen after low-LET radiation. Since appropriate cross-section functions for cancer induction for each particle species are not yet available, the conventional quality factor is used as an approximation to obtain numerical results for risks of excess cancer mortality. Risks are obtained for seven of the most radiosensitive organs as determined by the ICRP [stomach, colon, lung, bone marrow (BFO), bladder, esophagus and breast], beneath 10 g/cm2 aluminum shielding at solar minimum. Spectra are obtained for excess relative risk for each cancer per LET interval by calculating the average fluence-LET spectrum for the organ and converting to risk by multiplying by a factor proportional to R gamma L Q(L) before integrating over L, the unrestricted LET. Here R gamma is the risk coefficient for low-LET radiation (excess relative mortality per Sv) for the particular organ in question. The total risks of excess cancer mortality obtained are 1.3 and 1.1% to female and male crew, respectively, for a 1-year exposure at solar minimum. Uncertainties in these values are estimated to range between factors of 4 and 15 and are dominated by the biological uncertainties in the risk coefficients for low-LET radiation and in the LET (or energy) dependence of the risk cross sections (as approximated by the quality factor). The direct substitution of appropriate risk cross sections will eventually circumvent entirely the need to calculate, measure or use absorbed dose, equivalent dose and quality factor for such a high-energy charged-particle environment.

  7. Space Radiation Cancer Risks and Uncertainties for Mars Missions

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Schimmerling, W.; Wilson, J. W.; Peterson, L. E.; Badhwar, G. D.; Saganti, P. B.; Dicello, J. F.

    2001-01-01

    Projecting cancer risks from exposure to space radiation is highly uncertain because of the absence of data for humans and because of the limited radiobiology data available for estimating late effects from the high-energy and charge (HZE) ions present in the galactic cosmic rays (GCR). Cancer risk projections involve many biological and physical factors, each of which has a differential range of uncertainty due to the lack of data and knowledge. We discuss an uncertainty assessment within the linear-additivity model using the approach of Monte Carlo sampling from subjective error distributions that represent the lack of knowledge in each factor to quantify the overall uncertainty in risk projections. Calculations are performed using the space radiation environment and transport codes for several Mars mission scenarios. This approach leads to estimates of the uncertainties in cancer risk projections of 400-600% for a Mars mission. The uncertainties in the quality factors are dominant. Using safety standards developed for low-Earth orbit, long-term space missions (>90 days) outside the Earth's magnetic field are currently unacceptable if the confidence levels in risk projections are considered. Because GCR exposures involve multiple particle or delta-ray tracks per cellular array, our results suggest that the shape of the dose response at low dose rates may be an additional uncertainty for estimating space radiation risks.

  8. Space Radiation and Risks to Human Health

    NASA Technical Reports Server (NTRS)

    Huff, Janice L.

    2014-01-01

    The radiation environment in space poses significant challenges to human health and is a major concern for long duration manned space missions. Outside the Earth's protective magnetosphere, astronauts are exposed to higher levels of galactic cosmic rays, whose physical characteristics are distinct from terrestrial sources of radiation such as x-rays and gamma-rays. Galactic cosmic rays consist of high energy and high mass nuclei as well as high energy protons; they impart unique biological damage as they traverse through tissue with impacts on human health that are largely unknown. The major health issues of concern are the risks of radiation carcinogenesis, acute and late decrements to the central nervous system, degenerative tissue effects such as cardiovascular disease, as well as possible acute radiation syndromes due to an unshielded exposure to a large solar particle event. The NASA Human Research Program's Space Radiation Program Element is focused on characterization and mitigation of these space radiation health risks along with understanding these risks in context of the other biological stressors found in the space environment. In this overview, we will provide a description of these health risks and the Element's research strategies to understand and mitigate these risks.

  9. Radiation environments and absorbed dose estimations on manned space missions.

    PubMed

    Curtis, S B; Atwell, W; Beever, R; Hardy, A

    1986-01-01

    In order to make an assessment of radiation risk during manned missions in space, it is necessary first to have as accurate an estimation as possible of the radiation environment within the spacecraft to which the astronauts will be exposed. Then, with this knowledge and the inclusion of body self-shielding, estimations can be made of absorbed doses for various body organs (skin, eye, blood-forming organs, etc.). A review is presented of our present knowledge of the radiation environments and absorbed doses expected for several space mission scenarios selected for our development of the new radiation protection guidelines. The scenarios selected are a 90-day mission at an altitude (450 km) and orbital inclinations (28.5 degrees, 57 degrees and 90 degrees) appropriate for NASA's Space Station, a 15-day sortie to geosynchronous orbit and a 90-day lunar mission. All scenarios chosen yielded dose equivalents between five and ten rem to the blood forming organs if no large solar particle event were encountered. Such particle events could add considerable exposure particularly to the skin and eye for all scenarios except the one at 28.5 degrees orbital inclination.

  10. Managing Space Radiation Risks on Lunar and Mars Missions: Risk Assessment and Mitigation

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; George, K.; Hu, X.; Kim, M. H.; Nikjoo, H.

    2006-01-01

    Radiation-induced health risks are a primary concern for human exploration outside the Earth's magnetosphere, and require improved approaches to risk estimation and tools for mitigation including shielding and biological countermeasures. Solar proton events are the major concern for short-term lunar missions (<60 d), and for long-term missions (>60 d) such as Mars exploration, the exposures to the high energy and charge (HZE) ions that make-up the galactic cosmic rays are the major concern. Health risks from radiation exposure are chronic risks including carcinogenesis and degenerative tissue risks, central nervous system effects, and acute risk such as radiation sickness or early lethality. The current estimate is that a more than four-fold uncertainty exists in the projection of lifetime mortality risk from cosmic rays, which severely limits analysis of possible benefits of shielding or biological countermeasure designs. Uncertainties in risk projections are largely due to insufficient knowledge of HZE ion radiobiology, which has led NASA to develop a unique probabilistic approach to radiation protection. We review NASA's approach to radiation risk assessment including its impact on astronaut dose limits and application of the ALARA (As Low as Reasonably Achievable) principle. The recently opened NASA Space Radiation Laboratory (NSRL) provides the capability to simulate the cosmic rays in controlled ground-based experiments with biological and shielding models. We discuss how research at NSRL will lead to reductions in the uncertainties in risk projection models. In developing mission designs, the reduction of health risks and mission constraints including costs are competing concerns that need to be addressed through optimization procedures. Mitigating the risks from space radiation is a multi-factorial problem involving individual factors (age, gender, genetic makeup, and exposure history), operational factors (planetary destination, mission length, and period

  11. Managing Space Radiation Risks On Lunar and Mars Missions: Risk Assessment and Mitigation

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; George, K.; Hu, X.; Kim, M. H.; Nikjoo, H.

    2005-01-01

    Radiation-induced health risks are a primary concern for human exploration outside the Earth's magnetosphere, and require improved approaches to risk estimation and tools for mitigation including shielding and biological countermeasures. Solar proton events are the major concern for short-term lunar missions (<60 d), and for long-term missions (>60 d) such as Mars exploration, the exposures to the high energy and charge (HZE) ions that make-up the galactic cosmic rays are the major concern. Health risks from radiation exposure are chronic risks including carcinogenesis and degenerative tissue risks, central nervous system effects, and acute risk such as radiation sickness or early lethality. The current estimate is that a more than four-fold uncertainty exists in the projection of lifetime mortality risk from cosmic rays, which severely limits analysis of possible benefits of shielding or biological countermeasure designs. Uncertainties in risk projections are largely due to insufficient knowledge of HZE ion radiobiology, which has led NASA to develop a unique probabilistic approach to radiation protection. We review NASA's approach to radiation risk assessment including its impact on astronaut dose limits and application of the ALARA (As Low as Reasonably Achievable) principle. The recently opened NASA Space Radiation Laboratory (NSRL) provides the capability to simulate the cosmic rays in controlled ground-based experiments with biological and shielding models. We discuss how research at NSRL will lead to reductions in the uncertainties in risk projection models. In developing mission designs, the reduction of health risks and mission constraints including costs are competing concerns that need to be addressed through optimization procedures. Mitigating the risks from space radiation is a multi-factorial problem involving individual factors (age, gender, genetic makeup, and exposure history), operational factors (planetary destination, mission length, and period

  12. Managing Space Radiation Risks on Lunar and Mars Missions: Risk Assessment and Mitigation

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; George, K.; Hu, X.; Kim, M. H.; Nikjoo, H.; Ponomarev, A.; Ren, L.; Shavers, M. R.; Wu, H.

    2005-01-01

    Radiation-induced health risks are a primary concern for human exploration outside the Earth's magnetosphere, and require improved approaches to risk estimation and tools for mitigation including shielding and biological countermeasures. Solar proton events are the major concern for short-term lunar missions (<60 d), and for long-term missions (>60 d) such as Mars exploration, the exposures to the high energy and charge (HZE) ions that make-up the galactic cosmic rays are the major concern. Health risks from radiation exposure are chronic risks including carcinogenesis and degenerative tissue risks, central nervous system effects, and acute risk such as radiation sickness or early lethality. The current estimate is that a more than four-fold uncertainty exists in the projection of lifetime mortality risk from cosmic rays, which severely limits analysis of possible benefits of shielding or biological countermeasure designs. Uncertainties in risk projections are largely due to insufficient knowledge of HZE ion radiobiology, which has led NASA to develop a unique probabilistic approach to radiation protection. We review NASA's approach to radiation risk assessment including its impact on astronaut dose limits and application of the ALARA (As Low as Reasonably Achievable) principle. The recently opened NASA Space Radiation Laboratory (NSRL) provides the capability to simulate the cosmic rays in controlled ground-based experiments with biological and shielding models. We discuss how research at NSRL will lead to reductions in the uncertainties in risk projection models. In developing mission designs, the reduction of health risks and mission constraints including costs are competing concerns that need to be addressed through optimization procedures. Mitigating the risks from space radiation is a multi-factorial problem involving individual factors (age, gender, genetic makeup, and exposure history), operational factors (planetary destination, mission length, and period

  13. NASA Space Radiation Risk Project: Overview and Recent Results

    NASA Technical Reports Server (NTRS)

    Blattnig, Steve R.; Chappell, Lori J.; George, Kerry A.; Hada, Megumi; Hu, Shaowen; Kidane, Yared H.; Kim, Myung-Hee Y.; Kovyrshina, Tatiana; Norman, Ryan B.; Nounu, Hatem N.; Peterson, Leif E.; Plante, Ianik; Pluth, Janice M.; Ponomarev, Artem L.; Scott Carnell, Lisa A.; Slaba, Tony C.; Sridharan, Deepa; Xu, Xiaojing

    2015-01-01

    The NASA Space Radiation Risk project is responsible for integrating new experimental and computational results into models to predict risk of cancer and acute radiation syndrome (ARS) for use in mission planning and systems design, as well as current space operations. The project has several parallel efforts focused on proving NASA's radiation risk projection capability in both the near and long term. This presentation will give an overview, with select results from these efforts including the following topics: verification, validation, and streamlining the transition of models to use in decision making; relative biological effectiveness and dose rate effect estimation using a combination of stochastic track structure simulations, DNA damage model calculations and experimental data; ARS model improvements; pathway analysis from gene expression data sets; solar particle event probabilistic exposure calculation including correlated uncertainties for use in design optimization.

  14. [Socio-psychological and ecological aspects within the system of nuclear radiation risk mitigation].

    PubMed

    Davydov, B I; Ushakov, I B; Zuev, V G

    2004-01-01

    The authors bring into light several aspects of nuclear radiation risks, i.e. physical safety of nuclear technologies and ecology, place of operator within the nuclear radiation safety system (proficiency, protective culture, safety guides) and consider approaches to the human factor quantification within the system of mitigation of risks from nuclear technologies, and IAEA recommendations on probable risk estimation. Future investigations should be aimed at extension of the radiation sensitivity threshold, personnel selection as by psychological so genetic testing for immunity to ionizing radiation, development of pharmachemical and physical protectors and methods of enhancing nonspecific resistance to extreme, including radiation, environments, and building of radiation event simulators for training.

  15. [Fetus radiation doses from nuclear medicine and radiology diagnostic procedures. Potential risks and radiation protection instructions].

    PubMed

    Markou, Pavlos

    2007-01-01

    Although in pregnancy it is strongly recommended to avoid diagnostic nuclear medicine and radiology procedures, in cases of clinical necessity or when pregnancy is not known to the physician, these diagnostic procedures are to be applied. In such cases, counseling based on accurate information and comprehensive discussion about the risks of radiation exposure to the fetus should follow. In this article, estimations of the absorbed radiation doses due to nuclear medicine and radiology diagnostic procedures during the pregnancy and their possible risk effects to the fetus are examined and then discussed. Stochastic and detrimental effects are evaluated with respect to other risk factors and related to the fetus absorbed radiation dose and to the post-conception age. The possible termination of a pregnancy, due to radiation exposure is discussed. Special radiation protection instructions are given for radiation exposures in cases of possible, confirmed or unknown pregnancies. It is concluded that nuclear medicine and radiology diagnostic procedures, if not repeated during the pregnancy, are rarely an indication for the termination of pregnancy, because the dose received by the fetus is expected to be less than 100 mSv, which indicates the threshold dose for having deterministic effects. Therefore, the risk for the fetus due to these diagnostic procedures is low. However, stochastic effects are still possible but will be minimized if the radiation absorbed dose to the fetus is kept as low as possible.

  16. [Radiation conditions and radiation risks for cosmonauts flying to Mars using electrical jet microthrusters].

    PubMed

    Shafirkin, A V; Kolomenskiĭ, A V

    2008-01-01

    According to recent workups, the Mars mission spacecraft will be designed with an electrical jet microthrusters rather than a power reactor facility. The article contains analysis of the main sources of radiation hazard during the exploration mission using this cost-efficient, ecological, easy-to-operate propulsion powered by solar arrays. In addition, the authors make predictions of the generalized doses of ionizing radiation for mission durations of 730 and 900 days behind various shielding thicknesses, and on the Martian surface. Calculation algorithms are described and radiation risks are estimated for the crew life span and possible life time reduction in consequence of participation in the mission.

  17. Radiation risk and human space exploration.

    PubMed

    Schimmerling, W; Cucinotta, F A; Wilson, J W

    2003-01-01

    Radiation protection is essential to enable humans to live and work safely in space. Predictions about the nature and magnitude of the risks posed by space radiation are subject to very large uncertainties. Prudent use of worst-case scenarios may impose unacceptable constraints on shielding mass for spacecraft or habitats, tours of duty of crews on Space Station, and on the radius and duration of sorties on planetary surfaces. The NASA Space Radiation Health Program has been devised to develop the knowledge required to accurately predict and to efficiently manage radiation risk. The knowledge will be acquired by means of a peer-reviewed, largely ground-based and investigator-initiated, basic science research program. The NASA Strategic Plan to accomplish these objectives in a manner consistent with the high priority assigned to the protection and health maintenance of crews will be presented.

  18. Radiation risk and human space exploration

    NASA Technical Reports Server (NTRS)

    Schimmerling, W.; Cucinotta, F. A.; Wilson, J. W.

    2003-01-01

    Radiation protection is essential to enable humans to live and work safely in space. Predictions about the nature and magnitude of the risks posed by space radiation are subject to very large uncertainties. Prudent use of worst-case scenarios may impose unacceptable constraints on shielding mass for spacecraft or habitats, tours of duty of crews on Space Station, and on the radius and duration of sorties on planetary surfaces. The NASA Space Radiation Health Program has been devised to develop the knowledge required to accurately predict and to efficiently manage radiation risk. The knowledge will be acquired by means of a peer-reviewed, largely ground-based and investigator-initiated, basic science research program. The NASA Strategic Plan to accomplish these objectives in a manner consistent with the high priority assigned to the protection and health maintenance of crews will be presented. Published by Elsevier Science Ltd on behalf of COSPAR.

  19. Medical effects and risks of exposure to ionising radiation.

    PubMed

    Mettler, Fred A

    2012-03-01

    Effects and risk from exposure to ionising radiation depend upon the absorbed dose, dose rate, quality of radiation, specifics of the tissue irradiated and other factors such as the age of the individual. Effects may be apparent almost immediately or may take decades to be manifest. Cancer is the most important stochastic effect at absorbed doses of less than 1 Gy. The risk of cancer induction varies widely across different tissues; however, the risk of fatal radiation-induced cancer for a general population following chronic exposure is about 5% Sv(-1). Quantification of cancer risk at doses of less than 0.1 Gy remains problematic. Hereditary risks from irradiation that might result in effects to offspring of humans appear to be much lower and any such potential risks can only be estimated from animal models. At high doses (over 1 Gy) cell killing and modification causes deterministic effects such as skin burns, and bone marrow depression, in which case immunosuppression becomes a critical issue. Acute whole body penetrating gamma irradiation at doses in excess of 2 Gy results in varying degrees of acute radiation sickness and doses over 10 Gy are usually lethal as a result of combined organ injury.

  20. Patient radiation biological risk in computed tomography angiography procedure.

    PubMed

    Alkhorayef, M; Babikir, E; Alrushoud, A; Al-Mohammed, H; Sulieman, A

    2017-02-01

    Computed tomography angiography (CTA) has become the most valuable imaging modality for the diagnosis of blood vessel diseases; however, patients are exposed to high radiation doses and the probability of cancer and other biological effects is increased. The objectives of this study were to measure the patient radiation dose during a CTA procedure and to estimate the radiation dose and biological effects. The study was conducted in two radiology departments equipped with 64-slice CT machines (Aquilion) calibrated according to international protocols. A total of 152 patients underwent brain, lower limb, chest, abdomen, and pelvis examinations. The effective radiation dose was estimated using ImPACT scan software. Cancer and biological risks were estimated using the International Commission on Radiological Protection (ICRP) conversion factors. The mean patient dose value per procedure (dose length product [DLP], mGy·cm) for all examinations was 437.8 ± 166, 568.8 ± 194, 516.0 ± 228, 581.8 ± 175, and 1082.9 ± 290 for the lower limbs, pelvis, abdomen, chest, and cerebral, respectively. The lens of the eye, uterus, and ovaries received high radiation doses compared to thyroid and testis. The overall patient risk per CTA procedure ranged between 15 and 36 cancer risks per 1 million procedures. Patient risk from CTA procedures is high during neck and abdomen procedures. Special concern should be provided to the lens of the eye and thyroid during brain CTA procedures. Patient dose reduction is an important consideration; thus, staff should optimize the radiation dose during CTA procedures.

  1. Quantification of Contralateral Breast Dose and Risk Estimate of Radiation-Induced Contralateral Breast Cancer Among Young Women Using Tangential Fields and Different Modes of Breathing

    SciTech Connect

    Zurl, Brigitte; Stranzl, Heidi; Winkler, Peter; Kapp, Karin Sigrid

    2013-02-01

    Purpose: Whole breast irradiation with deep-inspiration breath-hold (DIBH) technique among left-sided breast cancer patients significantly reduces cardiac irradiation; however, a potential disadvantage is increased incidental irradiation of the contralateral breast. Methods and Materials: Contralateral breast dose (CBD) was calculated by comparing 400 treatment plans of 200 left-sided breast cancer patients whose tangential fields had been planned on gated and nongated CT data sets. Various anatomic and field parameters were analyzed for their impact on CBD. For a subgroup of patients (aged {<=}45 years) second cancer risk in the contralateral breast (CB) was modeled by applying the linear quadratic model, compound models, and compound models considering dose-volume information (DVH). Results: The mean CBD was significantly higher in DIBH with 0.69 Gy compared with 0.65 Gy in normal breathing (P=.01). The greatest impact on CBD was due to a shift of the inner field margin toward the CB in DIBH (mean 0.4 cm; range, 0-2), followed by field size in magnitude. Calculation with different risk models for CBC revealed values of excess relative risk/Gy ranging from 0.48-0.65 vs 0.46-0.61 for DIBH vs normal breathing, respectively. Conclusion: Contralateral breast dose, although within a low dose range, was mildly but significantly increased in 200 treatment plans generated under gated conditions, predominately due to a shift in the medial field margin. Risk modeling for CBC among women aged {<=}45 years also pointed to a higher risk when comparing DIBH with normal breathing. This risk, however, was substantially lower in the model considering DVH information. We think that clinical decisions should not be affected by this small increase in CBD with DIBH because DIBH is effective in reducing the dose to the heart in all patients.

  2. Cancer Risk Assessment for Space Radiation

    NASA Technical Reports Server (NTRS)

    Richmond, Robert C.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Predicting the occurrence of human cancer following exposure to any agent causing genetic damage is a difficult task. This is because the uncertainty of uniform exposure to the damaging agent, and the uncertainty of uniform processing of that damage within a complex set of biological variables, degrade the confidence of predicting the delayed expression of cancer as a relatively rare event within any given clinically normal individual. The radiation health research priorities for enabling long-duration human exploration of space were established in the 1996 NRC Report entitled "Radiation Hazards to Crews of Interplanetary Missions: Biological Issues and Research Strategies". This report emphasized that a 15-fold uncertainty in predicting radiation-induced cancer incidence must be reduced before NASA can commit humans to extended interplanetary missions. That report concluded that the great majority of this uncertainty is biologically based, while a minority is physically based due to uncertainties in radiation dosimetry and radiation transport codes. Since that report, the biologically based uncertainty has remained large, and the relatively small uncertainty associated with radiation dosimetry has increased due to the considerations raised by concepts of microdosimetry. In a practical sense, however, the additional uncertainties introduced by microdosimetry are encouraging since they are in a direction of lowered effective dose absorbed through infrequent interactions of any given cell with the high energy particle component of space radiation. The biological uncertainty in predicting cancer risk for space radiation derives from two primary facts. 1) One animal tumor study has been reported that includes a relevant spectrum of particle radiation energies, and that is the Harderian gland model in mice. Fact #1: Extension of cancer risk from animal models, and especially from a single study in an animal model, to humans is inherently uncertain. 2) One human database

  3. Are passive smoking, air pollution and obesity a greater mortality risk than major radiation incidents?

    PubMed Central

    Smith, Jim T

    2007-01-01

    Background Following a nuclear incident, the communication and perception of radiation risk becomes a (perhaps the) major public health issue. In response to such incidents it is therefore crucial to communicate radiation health risks in the context of other more common environmental and lifestyle risk factors. This study compares the risk of mortality from past radiation exposures (to people who survived the Hiroshima and Nagasaki atomic bombs and those exposed after the Chernobyl accident) with risks arising from air pollution, obesity and passive and active smoking. Methods A comparative assessment of mortality risks from ionising radiation was carried out by estimating radiation risks for realistic exposure scenarios and assessing those risks in comparison with risks from air pollution, obesity and passive and active smoking. Results The mortality risk to populations exposed to radiation from the Chernobyl accident may be no higher than that for other more common risk factors such as air pollution or passive smoking. Radiation exposures experienced by the most exposed group of survivors of Hiroshima and Nagasaki led to an average loss of life expectancy significantly lower than that caused by severe obesity or active smoking. Conclusion Population-averaged risks from exposures following major radiation incidents are clearly significant, but may be no greater than those from other much more common environmental and lifestyle factors. This comparative analysis, whilst highlighting inevitable uncertainties in risk quantification and comparison, helps place the potential consequences of radiation exposures in the context of other public health risks. PMID:17407581

  4. Broadband radiation modes: estimation and active control.

    PubMed

    Berkhoff, Arthur P

    2002-03-01

    In this paper we give a formulation of the most efficiently radiating vibration patterns of a vibrating body, the radiation modes, in the time domain. The radiation modes can be used to arrive at efficient weighting schemes for an array of sensors in order to reduce the controller dimensionality. Because these particular radiation modes are optimum in a broadband sense, they are termed broadband radiation modes. Methods are given to obtain these modes from measured data. The broadband radiation modes are used for the design of an actuator array in a feedback control system to reduce the sound power radiated from a plate. Three methods for the design of the actuator are compared, taking into account the reduction of radiated sound power in the controlled frequency range, but also the possible increase of radiated sound power in the uncontrolled frequency range.

  5. Technical Note: Estimating Aerosol Effects on Cloud Radiative Forcing

    SciTech Connect

    Ghan, Steven J.

    2013-10-09

    Estimating anthropogenic aerosol effects on the planetary energy balance through the aerosol influence on clouds using the difference in cloud radiative forcing from simulations with and without anthropogenic emissions produces estimates that are positively biased. A more representative method is suggested using the difference in cloud radiative forcing calculated with aerosol radiative effects neglected. The method also yields an aerosol radiative forcing decomposition that includes a term quantifying the impact of changes in surface albedo. The method requires only two additional diagnostic calculations: the whole-sky and clear-sky top-of-atmosphere radiative flux with aerosol radiative effects neglected.

  6. Emerging Radiation Health-Risk Mitigation Technologies

    SciTech Connect

    Wilson, J.W.; Cucinotta, F.A.; Schimmerling, W.

    2004-02-04

    Past space missions beyond the confines of the Earth's protective magnetic field have been of short duration and protection from the effects of solar particle events was of primary concern. The extension of operational infrastructure beyond low-Earth orbit to enable routine access to more interesting regions of space will require protection from the hazards of the accumulated exposures of Galactic Cosmic Rays (GCR). There are significant challenges in providing protection from the long-duration exposure to GCR: the human risks to the exposures are highly uncertain and safety requirements places unreasonable demands in supplying sufficient shielding materials in the design. A vigorous approach to future radiation health-risk mitigation requires a triage of techniques (using biological and technical factors) and reduction of the uncertainty in radiation risk models. The present paper discusses the triage of factors for risk mitigation with associated materials issues and engineering design methods.

  7. Submarine tower escape decompression sickness risk estimation.

    PubMed

    Loveman, G A M; Seddon, E M; Thacker, J C; Stansfield, M R; Jurd, K M

    2014-01-01

    Actions to enhance survival in a distressed submarine (DISSUB) scenario may be guided in part by knowledge of the likely risk of decompression sickness (DCS) should the crew attempt tower escape. A mathematical model for DCS risk estimation has been calibrated against DCS outcome data from 3,738 exposures of either men or goats to raised pressure. Body mass was used to scale DCS risk. The calibration data included more than 1,000 actual or simulated submarine escape exposures and no exposures with substantial staged decompression. Cases of pulmonary barotrauma were removed from the calibration data. The calibrated model was used to estimate the likelihood of DCS occurrence following submarine escape from the United Kingdom Royal Navy tower escape system. Where internal DISSUB pressure remains at - 0.1 MPa, escape from DISSUB depths < 200 meters is estimated to have DCS risk < 6%. Saturation at raised DISSUB pressure markedly increases risk, with > 60% DCS risk predicted for a 200-meter escape from saturation at 0.21 MPa. Using the calibrated model to predict DCS for direct ascent from saturation gives similar risk estimates to other published models.

  8. Radiation Risk Projections for Space Travel

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis

    2003-01-01

    Space travelers are exposed to solar and galactic cosmic rays comprised of protons and heavy ions moving with velocities close to the speed of light. Cosmic ray heavy ions are known to produce more severe types of biomolecular damage in comparison to terrestrial forms of radiation, however the relationship between such damage and disease has not been fully elucidated. On Earth, we are protected from cosmic rays by atmospheric and magnetic shielding, and only the remnants of cosmic rays in the form of ground level muons and other secondary radiations are present. Because human epidemiology data is lacking for cosmic rays, risk projection must rely on theoretical understanding and data from experimental models exposed to space radiation using charged particle accelerators to simulate space radiation. Although the risks of cancer and other late effects from cosmic rays are currently believed to present a severe challenge to space travel, this challenge is centered on our lack of confidence in risk projections methodologies. We review biophysics and radiobiology data on the effects of the cosmic ray heavy ions, and the current methods used to project radiation risks . Cancer risk projections are described as a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Risk projections for space travel are described using Monte-Carlo sampling from subjective error di stributions that represent the lack of knowledge in each factor that contributes to the projection model in order to quantify the overall uncertainty in risk projections. This analysis is applied to space mi ssion scenarios including lunar colony, deep space outpost, and a Mars mission. Results suggest that the number of days in space where cancer mortality risks can be assured at a 95% confidence level to be below the maximum acceptable risk for radi ation workers on Earth or the International Space Station is only on the order

  9. [Estimation of risk areas for hepatitis A].

    PubMed

    Braga, Ricardo Cerqueira Campos; Valencia, Luís Iván Ortiz; Medronho, Roberto de Andrade; Escosteguy, Claudia Caminha

    2008-08-01

    This study estimated hepatitis A risk areas in a region of Duque de Caxias, Rio de Janeiro State, Brazil. A cross-sectional study consisting of a hepatitis A serological survey and a household survey were conducted in 19 census tracts. Of these, 11 tracts were selected and 1,298 children from one to ten years of age were included in the study. Geostatistical techniques allowed modeling the spatial continuity of hepatitis A, non-use of filtered drinking water, time since installation of running water, and number of water taps per household and their spatial estimation through ordinary and indicator kriging. Adjusted models for the outcome and socioeconomic variables were isotropic; risk maps were constructed; cross-validation of the four models was satisfactory. Spatial estimation using the kriging method detected areas with increased risk of hepatitis A, independently of the urban administrative area in which the census tracts were located.

  10. Environmental chemical mutagens and genetic risks: Lessons from radiation genetics

    SciTech Connect

    Sankaranarayanan, K.

    1996-12-31

    The last three decades have witnessed substantial progress in the development and use of a variety of in vitro and in vivo assay systems for the testing of environmental chemicals which may pose a mutagenic hazard to humans. This is also true of basic studies in chemical mutagenesis on mechanisms, DNA repair, molecular dosimetry, structure-activity relationships, etc. However, the field of quantitative evaluation of genetic risks of environmental chemicals to humans is still in it infancy. This commentary addresses the question of how our experience in estimating genetic risks of exposure to ionizing radiation can be helpful in similar endeavors with environmental chemical mutagens. 24 refs., 3 tabs.

  11. Studies on the extended Techa river cohort: cancer risk estimation

    SciTech Connect

    Kossenko, M M.; Preston, D L.; Krestinina, L Y.; Degteva, M O.; Startsev, N V.; Thomas, T; Vyushkova, O V.; Anspaugh, L R.; Napier, Bruce A. ); Kozheurov, V P.; Ron, E; Akleyev, A V.

    2001-12-01

    Initial population-based studies of riverside residents were begun in the late 1950s and in 1967 a systematic effort was undertaken to develop a well-defined fixed cohort of Techa river residents, to carry out ongoing mortality and (limited) clinical follow-up of this cohort, and to provide individualized dose estimates for cohort members. Over the past decade, extensive efforts have been made to refine the cohort definition and improve both the follow-up and dosimetry data. Analyses of the Techa river cohort can provide useful quantitative estimates of the effects of low dose rate, chronic external and internal exposures on cancer mortality and incidence and non-cancer mortality rates. These risk estimates complement quantitative risk estimates for acute exposures based on the atomic bomb survivors and chronic exposure risk estimates from worker studies, including Mayak workers and other groups with occupational radiation exposures. As the dosimetry and follow-up are refined it may also be possible to gain useful insights into risks associated with 90Sr exposures.

  12. [Medium-term forecast of solar cosmic rays radiation risk during a manned Mars mission].

    PubMed

    Petrov, V M; Vlasov, A G

    2006-01-01

    Medium-term forecasting radiation hazard from solar cosmic rays will be vital in a manned Mars mission. Modern methods of space physics lack acceptable reliability in medium-term forecasting the SCR onset and parameters. The proposed estimation of average radiation risk from SCR during the manned Mars mission is made with the use of existing SCR fluence and spectrum models and correlation of solar particle event frequency with predicted Wolf number. Radiation risk is considered an additional death probability from acute radiation reactions (ergonomic component) or acute radial disease in flight. The algorithm for radiation risk calculation is described and resulted risk levels for various periods of the 23-th solar cycle are presented. Applicability of this method to advance forecasting and possible improvements are being investigated. Recommendations to the crew based on risk estimation are exemplified.

  13. Radiation effects: Modulating factors and risk assessment -- an overview.

    PubMed

    Wakeford, R

    2012-01-01

    Following low dose or low dose-rate exposures to ionising radiation, the principal resulting radiation-related risk is cancer. Site-specific cancer risk models have been developed that describe how the radiation-induced risk of a particular cancer type varies with the relevant tissue-specific absorbed dose of radiation. The degree of risk will also be determined by the radiation quality and the dose-rate, factors that will vary between types of radiation and cancer. Risk models also include a number of intrinsic factors that modify the radiation-related excess risk - sex, age at exposure, time since exposure, and attained age - although not all these factors enter into each site-specific model. Of some importance is how the radiation-related excess risk is transferred between populations when background incidence rates differ. For most cancer types, expert groups consider that the radiation-related excess risk in a population depends, to some extent, upon the background incidence rate, and therefore that radiation interacts with at least some of the major risk factors that determine the background risk for a person. For example, the radiation-induced risk of lung cancer depends on the degree of individual exposure to tobacco smoke, but the implicit assumption of the currently accepted risk transfer models is that interactions are a general feature of radiation-related cancer risk.

  14. Radiation Risk and the Mission to Mars

    NASA Astrophysics Data System (ADS)

    Durante, Marco

    2014-06-01

    Space radiation represents a major showstopper for human space exploration. While solar particle events and trapped protons can be effectively shielded, high-energy nuclei in the galactic cosmic radiation have a high biological effectiveness and cannot be shielded with the limited mass available on a spacecraft. A mission to Mars has been recently proposed (Inspiration Mars), consisting of a flyby with a crew of two astronauts starting in 2018 and lasting 501 days. Based on the recent measurements of the galactic cosmic ray dose on the Mars Science Laboratory and on the most recent update on the risk coefficients from the Atomic bomb survivors, it can be shown that the mission to Mars with current technology may expose the crew to a significant cancer risk.

  15. Spatial ascariasis risk estimation using socioeconomic variables.

    PubMed

    Valencia, Luis Iván Ortiz; Fortes, Bruno de Paula Menezes Drumond; Medronho, Roberto de Andrade

    2005-12-01

    Frequently, disease incidence is mapped as area data, for example, census tracts, districts or states. Spatial disease incidence can be highly heterogeneous inside these areas. Ascariasis is a highly prevalent disease, which is associated with poor sanitation and hygiene. Geostatistics was applied to model spatial distribution of Ascariasis risk and socioeconomic risk events in a poor community in Rio de Janeiro, Brazil. Data were gathered from a coproparasitologic and a domiciliary survey in 1550 children aged 1-9. Ascariasis risk and socioeconomic risk events were spatially estimated using Indicator Kriging. Cokriging models with a Linear Model of Coregionalization incorporating one socioeconomic variable were implemented. If a housewife attended school for less than four years, the non-use of a home water filter, a household density greater than one, and a household income lower than one Brazilian minimum wage increased the risk of Ascariasis. Cokriging improved spatial estimation of Ascariasis risk areas when compared to Indicator Kriging and detected more Ascariasis very-high risk areas than the GIS Overlay method.

  16. Main Sources and Doses of Space Radiation during Mars Missions and Total Radiation Risk for Cosmonauts

    NASA Astrophysics Data System (ADS)

    Mitrikas, Victor; Aleksandr, Shafirkin; Shurshakov, Vyacheslav

    This work contains calculation data of generalized doses and dose equivalents in critical organs and tissues of cosmonauts produces by galactic cosmic rays (GCR), solar cosmic rays (SCR) and the Earth’s radiation belts (ERB) that will impact crewmembers during a flight to Mars, while staying in the landing module and on the Martian surface, and during the return to Earth. Also calculated total radiation risk values during whole life of cosmonauts after the flight are presented. Radiation risk (RR) calculations are performed on the basis of a radiobiological model of radiation damage to living organisms, while taking into account reparation processes acting during continuous long-term exposure at various dose rates and under acute recurrent radiation impact. The calculations of RR are performed for crewmembers of various ages implementing a flight to Mars over 2 - 3 years in maximum and minimum of the solar cycle. The total carcinogenic and non-carcinogenic RR and possible life-span shortening are estimated on the basis of a model of the radiation death probability for mammals. This model takes into account the decrease in compensatory reserve of an organism as well as the increase in mortality rate and descent of the subsequent lifetime of the cosmonaut. The analyzed dose distributions in the shielding and body areas are applied to making model calculations of tissue equivalent spherical and anthropomorphic phantoms.

  17. Nuclear medicine dose equivalent a method for determination of radiation risk

    SciTech Connect

    Huda, W.

    1986-12-01

    Conventional nuclear medicine dosimetry involves specifying individual organ doses. The difficulties that can arise with this approach to radiation dosimetry are discussed. An alternative scheme is described that is based on the ICRP effective dose equivalent, H/sub E/, and which is a direct estimate of the average radiation risk to the patient. The mean value of H/sub E/ for seven common /sup 99m/Tc nuclear medicine procedures is 0.46 rem and the average radiation risk from this level of exposure is estimated to be comparable to the risk from smoking approx. 28 packs of cigarettes or driving approx. 1300 miles.

  18. Review of NASA approach to space radiation risk assessments for Mars exploration.

    PubMed

    Cucinotta, Francis A

    2015-02-01

    Long duration space missions present unique radiation protection challenges due to the complexity of the space radiation environment, which includes high charge and energy particles and other highly ionizing radiation such as neutrons. Based on a recommendation by the National Council on Radiation Protection and Measurements, a 3% lifetime risk of exposure-induced death for cancer has been used as a basis for risk limitation by the National Aeronautics and Space Administration (NASA) for low-Earth orbit missions. NASA has developed a risk-based approach to radiation exposure limits that accounts for individual factors (age, gender, and smoking history) and assesses the uncertainties in risk estimates. New radiation quality factors with associated probability distribution functions to represent the quality factor's uncertainty have been developed based on track structure models and recent radiobiology data for high charge and energy particles. The current radiation dose limits are reviewed for spaceflight and the various qualitative and quantitative uncertainties that impact the risk of exposure-induced death estimates using the NASA Space Cancer Risk (NSCR) model. NSCR estimates of the number of "safe days" in deep space to be within exposure limits and risk estimates for a Mars exploration mission are described.

  19. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    NASA Astrophysics Data System (ADS)

    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

  20. Estimating Terrorist Risk with Possibility Theory

    SciTech Connect

    J.L. Darby

    2004-11-30

    This report summarizes techniques that use possibility theory to estimate the risk of terrorist acts. These techniques were developed under the sponsorship of the Department of Homeland Security (DHS) as part of the National Infrastructure Simulation Analysis Center (NISAC) project. The techniques have been used to estimate the risk of various terrorist scenarios to support NISAC analyses during 2004. The techniques are based on the Logic Evolved Decision (LED) methodology developed over the past few years by Terry Bott and Steve Eisenhawer at LANL. [LED] The LED methodology involves the use of fuzzy sets, possibility theory, and approximate reasoning. LED captures the uncertainty due to vagueness and imprecision that is inherent in the fidelity of the information available for terrorist acts; probability theory cannot capture these uncertainties. This report does not address the philosophy supporting the development of nonprobabilistic approaches, and it does not discuss possibility theory in detail. The references provide a detailed discussion of these subjects. [Shafer] [Klir and Yuan] [Dubois and Prade] Suffice to say that these approaches were developed to address types of uncertainty that cannot be addressed by a probability measure. An earlier report discussed in detail the problems with using a probability measure to evaluate terrorist risk. [Darby Methodology]. Two related techniques are discussed in this report: (1) a numerical technique, and (2) a linguistic technique. The numerical technique uses traditional possibility theory applied to crisp sets, while the linguistic technique applies possibility theory to fuzzy sets. Both of these techniques as applied to terrorist risk for NISAC applications are implemented in software called PossibleRisk. The techniques implemented in PossibleRisk were developed specifically for use in estimating terrorist risk for the NISAC program. The LEDTools code can be used to perform the same linguistic evaluation as

  1. NASA Space Radiation Protection Strategies: Risk Assessment and Permissible Exposure Limits

    NASA Technical Reports Server (NTRS)

    Huff, J. L.; Patel, Z. S.; Simonsen, L. C.

    2017-01-01

    Permissible exposure limits (PELs) for short-term and career astronaut exposures to space radiation have been set and approved by NASA with the goal of protecting astronauts against health risks associated with ionizing radiation exposure. Short term PELs are intended to prevent clinically significant deterministic health effects, including performance decrements, which could threaten astronaut health and jeopardize mission success. Career PELs are implemented to control late occurring health effects, including a 3% risk of exposure induced death (REID) from cancer, and dose limits are used to prevent cardiovascular and central nervous system diseases. For radiation protection, meeting the cancer PEL is currently the design driver for galactic cosmic ray and solar particle event shielding, mission duration, and crew certification (e.g., 1-year ISS missions). The risk of cancer development is the largest known long-term health consequence following radiation exposure, and current estimates for long-term health risks due to cardiovascular diseases are approximately 30% to 40% of the cancer risk for exposures above an estimated threshold (Deep Space one-year and Mars missions). Large uncertainties currently exist in estimating the health risks of space radiation exposure. Improved understanding through radiobiology and physics research allows increased accuracy in risk estimation and is essential for ensuring astronaut health as well as for controlling mission costs, optimization of mission operations, vehicle design, and countermeasure assessment. We will review the Space Radiation Program Element's research strategies to increase accuracy in risk models and to inform development and validation of the permissible exposure limits.

  2. Almost efficient estimation of relative risk regression

    PubMed Central

    Fitzmaurice, Garrett M.; Lipsitz, Stuart R.; Arriaga, Alex; Sinha, Debajyoti; Greenberg, Caprice; Gawande, Atul A.

    2014-01-01

    Relative risks (RRs) are often considered the preferred measures of association in prospective studies, especially when the binary outcome of interest is common. In particular, many researchers regard RRs to be more intuitively interpretable than odds ratios. Although RR regression is a special case of generalized linear models, specifically with a log link function for the binomial (or Bernoulli) outcome, the resulting log-binomial regression does not respect the natural parameter constraints. Because log-binomial regression does not ensure that predicted probabilities are mapped to the [0,1] range, maximum likelihood (ML) estimation is often subject to numerical instability that leads to convergence problems. To circumvent these problems, a number of alternative approaches for estimating RR regression parameters have been proposed. One approach that has been widely studied is the use of Poisson regression estimating equations. The estimating equations for Poisson regression yield consistent, albeit inefficient, estimators of the RR regression parameters. We consider the relative efficiency of the Poisson regression estimator and develop an alternative, almost efficient estimator for the RR regression parameters. The proposed method uses near-optimal weights based on a Maclaurin series (Taylor series expanded around zero) approximation to the true Bernoulli or binomial weight function. This yields an almost efficient estimator while avoiding convergence problems. We examine the asymptotic relative efficiency of the proposed estimator for an increase in the number of terms in the series. Using simulations, we demonstrate the potential for convergence problems with standard ML estimation of the log-binomial regression model and illustrate how this is overcome using the proposed estimator. We apply the proposed estimator to a study of predictors of pre-operative use of beta blockers among patients undergoing colorectal surgery after diagnosis of colon cancer. PMID

  3. Radiation risk perception and public information

    SciTech Connect

    Boggs-Mayes, C.J.

    1988-01-01

    We as Health Physicists face what, at many times, appears to be a hopeless task. The task simply stated is informing the public about the risks (or lack thereof) of radiation. Unfortunately, the public has perceived radiation risks to be much greater than they actually are. An example of this problem is shown in a paper by Arthur C. Upton. Three groups of people -- the League of Women Voters, students, and Business and Professional Club members -- were asked to rank 30 sources of risk according to their contribution to the number of deaths in the United States. Not surprisingly, they ranked nuclear power much higher and medical x-rays much lower than the actual values. In addition to the perception problem, we are faced with another hurdle: health physicists as communicators. Members of the Health Physics Society (HPS) found that the communication styles of most health physicists appear to be dissimilar to those of the general public. These authors administered the Myers-Briggs Type Indicator to the HPS Baltimore-Washington Chapter. This test, a standardized test for psychological type developed by Isabel Myers, ask questions that provide a quantitative measure of our natural preferences in four areas. Assume that you as a health physicist have the necessary skills to communicate information about radiation to the public. Health physicists do nothing with these tools. Most people involved in radiation protection do not get involved with public information activies. What I will attempt to do is heighten your interest in such activities. I will share information about public information activities in which I have been involved and give you suggestions for sources of information and materials. 2 refs., 1 tab.

  4. Is cancer risk of radiation workers larger than expected?

    PubMed Central

    Jacob, P; Rühm, W; Walsh, L; Blettner, M; Hammer, G; Zeeb, H

    2009-01-01

    Occupational exposures to ionising radiation mainly occur at low-dose rates and may accumulate effective doses of up to several hundred milligray. The objective of the present study is to evaluate the evidence of cancer risks from such low-dose-rate, moderate-dose (LDRMD) exposures. Our literature search for primary epidemiological studies on cancer incidence and mortality risks from LDRMD exposures included publications from 2002 to 2007, and an update of the UK National Registry for Radiation Workers study. For each (LDRMD) study we calculated the risk for the same types of cancer among the atomic bomb survivors with the same gender proportion and matched quantities for dose, mean age attained and mean age at exposure. A combined estimator of the ratio of the excess relative risk per dose from the LDRMD study to the corresponding value for the atomic bomb survivors was 1.21 (90% CI 0.51 to 1.90). The present analysis does not confirm that the cancer risk per dose for LDRMD exposures is lower than for the atomic bomb survivors. This result challenges the cancer risk values currently assumed for occupational exposures. PMID:19570756

  5. Estimating the Radiation Dose to the Fetus in Prophylactic Internal Iliac Artery Balloon Occlusion: Three Cases

    PubMed Central

    Kai, Kentaro; Hamada, Tomohiro; Yuge, Akitoshi; Kiyosue, Hiro; Nishida, Yoshihiro; Nasu, Kaei; Narahara, Hisashi

    2015-01-01

    Background. Although radiation exposure is of great concern to expecting patients, little information is available on the fetal radiation dose associated with prophylactic internal iliac artery balloon occlusion (IIABO). Here we estimated the fetal radiation dose associated with prophylactic IIABO in Caesarean section (CS). Cases. We report our experience with the IIABO procedure in three consecutive patients with suspected placenta previa/accreta. Fetal radiation dose measurements were conducted prior to each CS by using an anthropomorphic phantom. Based on the simulated value, we calculated the fetal radiation dose as the absorbed dose. We found that the fetal radiation doses ranged from 12.88 to 31.6 mGy. The fetal radiation dose during the prophylactic IIABOs did not exceed 50 mGy. Conclusion. The IIABO procedure could result in a very small increase in the risk of harmful effects to the fetus. PMID:26180648

  6. Radiobiological foundation of crew radiation risk for mars mission

    NASA Astrophysics Data System (ADS)

    Shafirkin, A.

    The results of a comprehensive clinico-physiological study of 250 dogs after 22 hours per day chronic exposure to gamma -radiation throughout their life are presented. The exposure duration was 3 and 6 years. The dose rate varied between 25 and 150 cSv/year to simulate galactic cosmic ray dose of crew members during mars mission. Several groups of the dogs received an additional acute dose of 10 and 50 cSv during a day three times per year to simulate stochastic irradiation caused by solar cosmic rays. Data on the status of regulatory systems of organism, exchange processes dynamics, organism reaction on additional functional loads are also presented. Organism reaction and dynamics of kinetic relations are considered in detail for most radiosensitive and regenerating tissue systems of the organism, namely, bloodforming system and spermatogenic epithelium. The results on life span reduction of the dogs and dog race characteristics after the radiation exposure are discussed. Based on the results obtained in this study and in model experiments realized with big amount of small laboratory animals that were exposed to a wide dose range, using other published data, mathematical models were developed, e. g. a model of radiation damage forming as dependent on time with taking into account recovery processes, and a model of radiation mortality rate of mammals. Based on these models and analysis of radiation environment behind various shielding on the route to Mars, crew radiation risk was calculated for space missions of various durations. Total radiation risk values for cosmonaut lifetime after the missions were also estimated together with expected life span reduction.

  7. Radiobiological foundation of crew radiation risk for Mars mission

    NASA Astrophysics Data System (ADS)

    Aleksandr, Shafirkin; Grigoriev, Yurj

    The results of a comprehensive clinico-physiological study of 250 dogs after 22 hours per day chronic exposure to gamma-radiation throughout their life are presented. The exposure duration was 3 and 6 years. The dose rate varied between 25 and 150 cSv/year to simulate galactic cosmic ray dose of crew members during mars mission. Several groups of the dogs received an additional acute dose of 10 and 50 cSv during a day three times per year to simulate stochastic irradiation caused by solar cosmic rays. Data on the status of regulatory systems of organism, exchange processes dynamics, organism reaction on additional functional loads are also presented. Organism reaction and dynamics of kinetic relations are considered in detail for most radiosensitive and regenerating tissue systems of the organism, namely, bloodforming system and spermatogenic epithelium. The results on life span reduction of the dogs and dog race characteristics after the radiation exposure are discussed. Based on the results obtained in this study and in model experiments realized with big amount of small laboratory animals that were exposed to a wide dose range, using other published data, mathematical models were developed, e. g. a model of radiation damage forming as dependent on time with taking into account recovery processes, and a model of radiation mortality rate of mammals. Based on these models and analysis of radiation environment behind various shielding on the route to Mars, crew radiation risk was calculated for space missions of various durations. Total radiation risk values for cosmonaut lifetime after the missions were also estimated together with expected life span reduction.

  8. Estimates of health risk from exposure to radioactive pollutants

    SciTech Connect

    Sullivan, R.E.; Nelson, N.S.; Ellett, W.H.; Dunning, D.E. Jr.; Leggett, R.W.; Yalcintas, M.G.; Eckerman, K.F.

    1981-11-01

    A dosimetric and health effects analysis has been performed for the Office of Radiation Programs of the Environmental Protection Agency (EPA) to assess potential hazards from radioactive pollutants. Contemporary dosimetric methods were used to obtain estimates of dose rates to reference organs from internal exposures due to either inhalation of contaminated air or ingestion of contaminated food, or from external exposures due to either immersion in contaminated air or proximity to contaminated ground surfaces. These dose rates were then used to estimate the number of premature cancer deaths arising from such exposures and the corresponding number of years of life lost in a cohort of 100,000 persons, all simultaneously liveborn and all going through life with the same risks of dying from competing causes. The risk of dying from a competing cause for a given year was taken to be the probability of dying from all causes as given in a recent actuarial life table for the total US population.

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

    SciTech Connect

    Crook, J.E.; Carlton, J.E.; Stabin, M.; Watson, E.

    1985-01-01

    Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. We 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 radiation. 5 refs., 3 tabs.

  10. Estimated Autism Risk and Older Reproductive Age

    PubMed Central

    King, Marissa D.; Fountain, Christine; Dakhlallah, Diana

    2009-01-01

    Objectives. We sought to estimate the risk for autism associated with maternal and paternal age across successive birth cohorts. Methods. We linked birth records and autism diagnostic records from the California Department of Developmental Services for children born in California between 1992 and 2000 to calculate the risk associated with maternal and paternal age for each birth cohort as well as for the pooled data. Results. The categorical risks associated with maternal age over 40 years ranged from a high of 1.84 (95% confidence interval [CI] = 1.37, 2.47) to a low of 1.27 (95% CI = 0.95, 1.69). The risk associated with paternal age ranged from 1.29 (95% CI = 1.03, 1.6) to 1.71 (95% CI = 1.41, 2.08). Conclusions. Pooling data across multiple birth cohorts inflates the risk associated with paternal age. Analyses that do not suffer from problems produced by pooling across birth cohorts demonstrated that advanced maternal age, rather than paternal age, may pose greater risk. Future research examining parental age as a risk factor must be careful to avoid the paradoxes that can arise from pooling data, particularly during periods of social demographic change. PMID:19608957

  11. Estimating population health risk from low-level environmental radon

    SciTech Connect

    Fisher, D.R.

    1980-01-01

    Although incidence of respiratory cancer is directly related to inhalation of radon and radon daughters, the magnitude of the actual risk is uncertain for members of the general population exposed for long periods to low-level concentrations. Currently, any such estimate of the risk must rely on data obtained through previous studies of underground-miner populations. Several methods of risk analysis have resulted from these studies. Since the breathing atmospheres, smoking patterns, and physiology are different between miners and the general public, overestimates of lung cancer risk to the latter may have resulted. Strong evidence exists to support the theory of synergistic action between alpha radiation and other agents, and therefore a modified relative risk model was developed to predict lung cancer risks to the general public. The model considers latent period, observation period, age dependency, and inherent risks from smoking or geographical location. A test of the model showed excellent agreement with results of the study of Czechoslovakian uranium miners, for which the necessary time factors were available. The risk model was also used to predict lung cancer incidence among residents of homes on reclaimed Florida phosphate lands, and results of this analysis indicate that over the space of many years, the increased incidence of lung cancer due to elevated radon levels may be indisgtinguishable from those due to other causes.

  12. Risk Estimation Methodology for Launch Accidents.

    SciTech Connect

    Clayton, Daniel James; Lipinski, Ronald J.; Bechtel, Ryan D.

    2014-02-01

    As compact and light weight power sources with reliable, long lives, Radioisotope Power Systems (RPSs) have made space missions to explore the solar system possible. Due to the hazardous material that can be released during a launch accident, the potential health risk of an accident must be quantified, so that appropriate launch approval decisions can be made. One part of the risk estimation involves modeling the response of the RPS to potential accident environments. Due to the complexity of modeling the full RPS response deterministically on dynamic variables, the evaluation is performed in a stochastic manner with a Monte Carlo simulation. The potential consequences can be determined by modeling the transport of the hazardous material in the environment and in human biological pathways. The consequence analysis results are summed and weighted by appropriate likelihood values to give a collection of probabilistic results for the estimation of the potential health risk. This information is used to guide RPS designs, spacecraft designs, mission architecture, or launch procedures to potentially reduce the risk, as well as to inform decision makers of the potential health risks resulting from the use of RPSs for space missions.

  13. DNA Damage Signals and Space Radiation Risk

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.

    2011-01-01

    Space radiation is comprised of high-energy and charge (HZE) nuclei and protons. The initial DNA damage from HZE nuclei is qualitatively different from X-rays or gamma rays due to the clustering of damage sites which increases their complexity. Clustering of DNA damage occurs on several scales. First there is clustering of single strand breaks (SSB), double strand breaks (DSB), and base damage within a few to several hundred base pairs (bp). A second form of damage clustering occurs on the scale of a few kbp where several DSB?s may be induced by single HZE nuclei. These forms of damage clusters do not occur at low to moderate doses of X-rays or gamma rays thus presenting new challenges to DNA repair systems. We review current knowledge of differences that occur in DNA repair pathways for different types of radiation and possible relationships to mutations, chromosomal aberrations and cancer risks.

  14. From mechanisms to risk estimation--bridging the chasm.

    PubMed

    Curtis, S B; Hazelton, W D; Luebeck, E G; Moolgavkar, S H

    2004-01-01

    We have a considerable amount of work ahead of us to determine the importance of the wealth of new information emerging in the fields of sub-cellular, cellular and tissue biology in order to improve the estimation of radiation risk at low dose and protracted dose-rate. In this paper, we suggest that there is a need to develop models of the specific health effects of interest (e.g., carcinogenesis in specific tissues), which embody as much of the mechanistic (i.e., biological) information as is deemed necessary. Although it is not realistic to expect that every radiation-induced process should or could be included, we can hope that the major factors that shape the time dependence of evolution of damage can be identified and quantified to the point where reasonable estimations of risk can be made. Regarding carcinogenesis in particular, the structure of the model itself plays a role in determining the relative importance of various processes. We use a specific form of a multi-stage carcinogenic model to illustrate this point. We show in a review of the application of this model to lung cancer incidence and mortality in two exposed populations that for both high- and low-LET radiation, there is evidence of an "inverse dose-rate" or protraction effect. This result could be of some considerable importance, because it would imply that risk from protracted exposure even to low-LET radiation might be greater than from acute exposure, an opinion not currently held in the radiation protection community. This model also allows prediction of the evolution of the risk over the lifetimes of the exposed individuals. One inference is that radiation-induced initiation (i.e., the first cellular carcinogenic event(s) occurring in normal tissue after the passage of the radiation) may not be the driving factor in the risk, but more important may be the effects of the radiation on already-initiated cells in the tissue. Although present throughout the length of the exposure, radiation

  15. Individual-based model for radiation risk assessment

    NASA Astrophysics Data System (ADS)

    Smirnova, O.

    A mathematical model is developed which enables one to predict the life span probability for mammals exposed to radiation. It relates statistical biometric functions with statistical and dynamic characteristics of an organism's critical system. To calculate the dynamics of the latter, the respective mathematical model is used too. This approach is applied to describe the effects of low level chronic irradiation on mice when the hematopoietic system (namely, thrombocytopoiesis) is the critical one. For identification of the joint model, experimental data on hematopoiesis in nonirradiated and irradiated mice, as well as on mortality dynamics of those in the absence of radiation are utilized. The life span probability and life span shortening predicted by the model agree with corresponding experimental data. Modeling results show the significance of ac- counting the variability of the individual radiosensitivity of critical system cells when estimating the radiation risk. These findings are corroborated by clinical data on persons involved in the elimination of the Chernobyl catastrophe after- effects. All this makes it feasible to use the model for radiation risk assessments for cosmonauts and astronauts on long-term missions such as a voyage to Mars or a lunar colony. In this case the model coefficients have to be determined by making use of the available data for humans. Scenarios for the dynamics of dose accumulation during space flights should also be taken into account.

  16. Quality control and estimation of global solar radiation in China

    SciTech Connect

    Tang, Wenjun; He, Jie; Yang, Kun; Qin, Jun

    2010-03-15

    Measurements of surface radiation in China are too sparse to meet demand for scientific research and engineering applications. Moreover, the radiation data often include erroneous and questionable values though preliminary quality-check has been done before the data release. Therefore, quality control of radiation data is often a prerequisite for using these data. In this study, a set of quality-check procedures were implemented to control the quality of the solar radiation measurements at 97 stations in China. A hybrid model for estimating global solar radiation was then evaluated against the controlled data. The results show that the model can estimate the global radiation with accuracy of MBE less than 1.5 MJ m{sup -2} and RMSE less than 2.8 MJ m{sup -2} for daily radiation and RMSE less than 2.0 MJ m{sup -2} for monthly-mean daily radiation at individual stations over most of China except at a few stations where unsatisfactory estimates were possibly caused by severe air pollution or too dense clouds. The MBE averaged over all stations are about 0.7 MJ m{sup -2} and RMSE about 2.0 MJ m{sup -2} for daily radiation and RMSE about 1.3 MJ m{sup -2} for monthly-mean daily radiation. Finally, this model was used to fill data gaps and to expand solar radiation data set using routine meteorological station data in China. This data set would substantially contribute to some radiation-related scientific studies and engineering applications in China. (author)

  17. A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

    NASA Technical Reports Server (NTRS)

    Edmonds, L. D.

    2016-01-01

    Since advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

  18. A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

    NASA Technical Reports Server (NTRS)

    Edmonds, L. D.

    2016-01-01

    Because advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

  19. Personalized Cancer Risk Assessments for Space Radiation Exposures

    PubMed Central

    Locke, Paul A.; Weil, Michael M.

    2016-01-01

    Individuals differ in their susceptibility to radiogenic cancers, and there is evidence that this inter-individual susceptibility extends to HZE ion-induced carcinogenesis. Three components of individual risk: sex, age at exposure, and prior tobacco use, are already incorporated into the NASA cancer risk model used to determine safe days in space for US astronauts. Here, we examine other risk factors that could potentially be included in risk calculations. These include personal and family medical history, the presence of pre-malignant cells that could undergo malignant transformation as a consequence of radiation exposure, the results from phenotypic assays of radiosensitivity, heritable genetic polymorphisms associated with radiosensitivity, and postflight monitoring. Inclusion of these additional risk or risk reduction factors has the potential to personalize risk estimates for individual astronauts and could influence the determination of safe days in space. We consider how this type of assessment could be used and explore how the provisions of the federal Genetic Information Non-discrimination Act could impact the collection, dissemination and use of this information by NASA. PMID:26942127

  20. Auditory risk estimates for youth target shooting

    PubMed Central

    Meinke, Deanna K.; Murphy, William J.; Finan, Donald S.; Lankford, James E.; Flamme, Gregory A.; Stewart, Michael; Soendergaard, Jacob; Jerome, Trevor W.

    2015-01-01

    Objective To characterize the impulse noise exposure and auditory risk for youth recreational firearm users engaged in outdoor target shooting events. The youth shooting positions are typically standing or sitting at a table, which places the firearm closer to the ground or reflective surface when compared to adult shooters. Design Acoustic characteristics were examined and the auditory risk estimates were evaluated using contemporary damage-risk criteria for unprotected adult listeners and the 120-dB peak limit suggested by the World Health Organization (1999) for children. Study sample Impulses were generated by 26 firearm/ammunition configurations representing rifles, shotguns, and pistols used by youth. Measurements were obtained relative to a youth shooter’s left ear. Results All firearms generated peak levels that exceeded the 120 dB peak limit suggested by the WHO for children. In general, shooting from the seated position over a tabletop increases the peak levels, LAeq8 and reduces the unprotected maximum permissible exposures (MPEs) for both rifles and pistols. Pistols pose the greatest auditory risk when fired over a tabletop. Conclusion Youth should utilize smaller caliber weapons, preferably from the standing position, and always wear hearing protection whenever engaging in shooting activities to reduce the risk for auditory damage. PMID:24564688

  1. The quantitative estimation of IT-related risk probabilities.

    PubMed

    Herrmann, Andrea

    2013-08-01

    How well can people estimate IT-related risk? Although estimating risk is a fundamental activity in software management and risk is the basis for many decisions, little is known about how well IT-related risk can be estimated at all. Therefore, we executed a risk estimation experiment with 36 participants. They estimated the probabilities of IT-related risks and we investigated the effect of the following factors on the quality of the risk estimation: the estimator's age, work experience in computing, (self-reported) safety awareness and previous experience with this risk, the absolute value of the risk's probability, and the effect of knowing the estimates of the other participants (see: Delphi method). Our main findings are: risk probabilities are difficult to estimate. Younger and inexperienced estimators were not significantly worse than older and more experienced estimators, but the older and more experienced subjects better used the knowledge gained by knowing the other estimators' results. Persons with higher safety awareness tend to overestimate risk probabilities, but can better estimate ordinal ranks of risk probabilities. Previous own experience with a risk leads to an overestimation of its probability (unlike in other fields like medicine or disasters, where experience with a disease leads to more realistic probability estimates and nonexperience to an underestimation).

  2. Radiative heat transfer estimation in pipes with various wall emissivities

    NASA Astrophysics Data System (ADS)

    Robin, Langebach; Christoph, Haberstroh

    2017-02-01

    Radiative heat transfer is usually of substantial importance in cryogenics when systems are designed and thermal budgeting is carried out. However, the contribution of pipes is commonly assumed to be comparably low since the warm and cold ends as well as their cross section are fairly small. Nevertheless, for a first assessment of each pipe rough estimates are always appreciated. In order to estimate the radiative heat transfer with traditional “paper and pencil“ methods there is only one analytical case available in literature – the case of plane-parallel plates. This case can only be used to calculate the theoretical lower and the upper asymptotic values of the radiative heat transfer, since pipe wall radiation properties are not taken into account. For this paper we investigated the radiative heat transfer estimation in pipes with various wall emissivities with the help of numerical simulations. Out of a number of calculation series we could gain an empirical extension for the used approach of plane-parallel plates. The model equation can be used to carry out enhanced paper and pencil estimations for the radiative heat transfer through pipes without demanding numerical simulations.

  3. Observationally constrained estimates of carbonaceous aerosol radiative forcing.

    PubMed

    Chung, Chul E; Ramanathan, V; Decremer, Damien

    2012-07-17

    Carbonaceous aerosols (CA) emitted by fossil and biomass fuels consist of black carbon (BC), a strong absorber of solar radiation, and organic matter (OM). OM scatters as well as absorbs solar radiation. The absorbing component of OM, which is ignored in most climate models, is referred to as brown carbon (BrC). Model estimates of the global CA radiative forcing range from 0 to 0.7 Wm(-2), to be compared with the Intergovernmental Panel on Climate Change's estimate for the pre-Industrial to the present net radiative forcing of about 1.6 Wm(-2). This study provides a model-independent, observationally based estimate of the CA direct radiative forcing. Ground-based aerosol network data is integrated with field data and satellite-based aerosol observations to provide a decadal (2001 through 2009) global view of the CA optical properties and direct radiative forcing. The estimated global CA direct radiative effect is about 0.75 Wm(-2) (0.5 to 1.0). This study identifies the global importance of BrC, which is shown to contribute about 20% to 550-nm CA solar absorption globally. Because of the inclusion of BrC, the net effect of OM is close to zero and the CA forcing is nearly equal to that of BC. The CA direct radiative forcing is estimated to be about 0.65 (0.5 to about 0.8) Wm(-2), thus comparable to or exceeding that by methane. Caused in part by BrC absorption, CAs have a net warming effect even over open biomass-burning regions in Africa and the Amazon.

  4. Observationally constrained estimates of carbonaceous aerosol radiative forcing

    PubMed Central

    Chung, Chul E.; Ramanathan, V.; Decremer, Damien

    2012-01-01

    Carbonaceous aerosols (CA) emitted by fossil and biomass fuels consist of black carbon (BC), a strong absorber of solar radiation, and organic matter (OM). OM scatters as well as absorbs solar radiation. The absorbing component of OM, which is ignored in most climate models, is referred to as brown carbon (BrC). Model estimates of the global CA radiative forcing range from 0 to 0.7 Wm-2, to be compared with the Intergovernmental Panel on Climate Change’s estimate for the pre-Industrial to the present net radiative forcing of about 1.6 Wm-2. This study provides a model-independent, observationally based estimate of the CA direct radiative forcing. Ground-based aerosol network data is integrated with field data and satellite-based aerosol observations to provide a decadal (2001 through 2009) global view of the CA optical properties and direct radiative forcing. The estimated global CA direct radiative effect is about 0.75 Wm-2 (0.5 to 1.0). This study identifies the global importance of BrC, which is shown to contribute about 20% to 550-nm CA solar absorption globally. Because of the inclusion of BrC, the net effect of OM is close to zero and the CA forcing is nearly equal to that of BC. The CA direct radiative forcing is estimated to be about 0.65 (0.5 to about 0.8) Wm-2, thus comparable to or exceeding that by methane. Caused in part by BrC absorption, CAs have a net warming effect even over open biomass-burning regions in Africa and the Amazon. PMID:22753522

  5. Spectral estimates of solar radiation intercepted by corn canopies

    NASA Technical Reports Server (NTRS)

    Bauer, M. E. (Principal Investigator); Daughtry, C. S. T.; Gallo, K. P.

    1982-01-01

    Reflectance factor data were acquired with a Landsat band radiometer throughout two growing seasons for corn (Zea mays L.) canopies differing in planting dates, populations, and soil types. Agronomic data collected included leaf area index (LAI), biomass, development stage, and final grain yields. The spectral variable, greenness, was associated with 78 percent of the variation in LAI over all treatments. Single observations of LAI or greenness have limited value in predicting corn yields. The proportions of solar radiation intercepted (SRI) by these canopies were estimated using either measured LAI or greenness. Both SRI estimates, when accumulated over the growing season, accounted for approximately 65 percent of the variation in yields. Models which simulated the daily effects of weather and intercepted solar radiation on growth had the highest correlations to grain yields. This concept of estimating intercepted solar radiation using spectral data represents a viable approach for merging spectral and meteorological data for crop yield models.

  6. Stochastic Effects in Computational Biology of Space Radiation Cancer Risk

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Pluth, Janis; Harper, Jane; O'Neill, Peter

    2007-01-01

    Estimating risk from space radiation poses important questions on the radiobiology of protons and heavy ions. We are considering systems biology models to study radiation induced repair foci (RIRF) at low doses, in which less than one-track on average transverses the cell, and the subsequent DNA damage processing and signal transduction events. Computational approaches for describing protein regulatory networks coupled to DNA and oxidative damage sites include systems of differential equations, stochastic equations, and Monte-Carlo simulations. We review recent developments in the mathematical description of protein regulatory networks and possible approaches to radiation effects simulation. These include robustness, which states that regulatory networks maintain their functions against external and internal perturbations due to compensating properties of redundancy and molecular feedback controls, and modularity, which leads to general theorems for considering molecules that interact through a regulatory mechanism without exchange of matter leading to a block diagonal reduction of the connecting pathways. Identifying rate-limiting steps, robustness, and modularity in pathways perturbed by radiation damage are shown to be valid techniques for reducing large molecular systems to realistic computer simulations. Other techniques studied are the use of steady-state analysis, and the introduction of composite molecules or rate-constants to represent small collections of reactants. Applications of these techniques to describe spatial and temporal distributions of RIRF and cell populations following low dose irradiation are described.

  7. Perception of low dose radiation risks among radiation researchers in Korea

    PubMed Central

    Seo, Songwon; Lee, Dalnim; Park, Sunhoo; Jin, Young Woo; Lee, Seung-Sook

    2017-01-01

    Expert’s risk evaluation of radiation exposure strongly influences the public’s risk perception. Experts can inform laypersons of significant radiation information including health knowledge based on experimental data. However, some experts’ radiation risk perception is often based on non-conclusive scientific evidence (i.e., radiation levels below 100 millisievert), which is currently under debate. Examining perception levels among experts is important for communication with the public since these individual’s opinions have often exacerbated the public’s confusion. We conducted a survey of Korean radiation researchers to investigate their perceptions of the risks associated with radiation exposure below 100 millisievert. A linear regression analysis revealed that having ≥ 11 years’ research experience was a critical factor associated with radiation risk perception, which was inversely correlated with each other. Increased opportunities to understand radiation effects at < 100 millisievert could alter the public’s risk perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects < 100 millisievert is necessary for successful public communication. We concluded that sustained education addressing scientific findings is a critical attribute that will affect the risk perception of radiation exposure. PMID:28166286

  8. Estimating sound power radiated from rectangular baffled panels using a radiation factor.

    PubMed

    Palumbo, Dan

    2009-10-01

    A method is introduced which is shown to predict radiated sound power from rectangular baffled panels. The method employs a filtered wavenumber transform to extract the power in the supersonic wavenumbers on the panel and a radiation factor to scale the supersonic power to match the actual radiated sound power. Although empirically derived, the radiation factor is shown to be related to the radiation efficiency of an infinite panel. The radiation factor is simple, depending only on the ratio of the wavenumbers of the panel to the radiation medium, and the method is straightforward to use, requiring only the panel normal velocities. The computation is efficient, as much as two orders of magnitude faster than a Rayleigh integration, thus providing a means of combining sound power predictions with finite element optimizations. A formula is derived which predicts the lowest frequency for which the method is valid as a function of the bin width of the wavenumber transform. The radiation factor method is shown to produce radiated sound power estimates which favorably compare to estimates derived from intensity measurements of physical test specimens and to Rayleigh integral estimates computed using both simulated and measured velocities.

  9. Solar Radiation Estimated Through Mesoscale Atmospheric Modeling over Northeast Brazil

    NASA Astrophysics Data System (ADS)

    de Menezes Neto, Otacilio Leandro; Costa, Alexandre Araújo; Ramalho, Fernando Pinto; de Maria, Paulo Henrique Santiago

    2009-03-01

    The use of renewable energy sources, like solar, wind and biomass is rapidly increasing in recent years, with solar radiation as a particularly abundant energy source over Northeast Brazil. A proper quantitative knowledge of the incoming solar radiation is of great importance for energy planning in Brazil, serving as basis for developing future projects of photovoltaic power plants and solar energy exploitation. This work presents a methodology for mapping the incoming solar radiation at ground level for Northeast Brazil, using a mesoscale atmospheric model (Regional Atmospheric Modeling System—RAMS), calibrated and validated using data from the network of automatic surface stations from the State Foundation for Meteorology and Water Resources from Ceará (Fundação Cearense de Meteorologia e Recursos Hídricos- FUNCEME). The results showed that the model exhibits systematic errors, overestimating surface radiation, but that, after the proper statistical corrections, using a relationship between the model-predicted cloud fraction, the ground-level observed solar radiation and the incoming solar radiation estimated at the top of the atmosphere, a correlation of 0.92 with a confidence interval of 13.5 W/m2 is found for monthly data. Using this methodology, we found an estimate for annual average incoming solar radiation over Ceará of 215 W/m2 (maximum in October: 260 W/m2).

  10. Risks of carcinogenesis from electromagnetic radiation of mobile telephony devices.

    PubMed

    Yakymenko, I; Sidorik, E

    2010-07-01

    Intensive implementation of mobile telephony technology in everyday human life during last two decades has given a possibility for epidemiological estimation of long-term effects of chronic exposure of human organism to low-intensive microwave (MW) radiation. Latest epidemiological data reveal a significant increase in risk of development of some types of tumors in chronic (over 10 years) users of mobile phone. It was detected a significant increase in incidence of brain tumors (glioma, acoustic neuroma, meningioma), parotid gland tumor, seminoma in long-term users of mobile phone, especially in cases of ipsilateral use (case-control odds ratios from 1.3 up to 6.1). Two epidemiological studies have indicated a significant increase of cancer incidence in people living close to the mobile telephony base station as compared with the population from distant area. These data raise a question of adequacy of modern safety limits of electromagnetic radiation (EMR) exposure for humans. For today the limits were based solely on the conception of thermal mechanism of biological effects of RF/MW radiation. Meantime the latest experimental data indicate the significant metabolic changes in living cell under the low-intensive (non-thermal) EMR exposure. Among reproducible biological effects of low-intensive MWs are reactive oxygen species overproduction, heat shock proteins expression, DNA damages, apoptosis. The lack of generally accepted mechanism of biological effects of low-intensive non-ionizing radiation doesn't permit to disregard the obvious epidemiological and experimental data of its biological activity. Practical steps must be done for reasonable limitation of excessive EMR exposure, along with the implementation of new safety limits of mobile telephony devices radiation, and new technological decisions, which would take out the source of radiation from human brain.

  11. The carcinogenic risks of low-LET and high-LET ionizing radiations. Revision

    SciTech Connect

    Fabrikant, J.I. |

    1991-08-01

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary.

  12. The carcinogenic risks of low-LET and high-LET ionizing radiations

    SciTech Connect

    Fabrikant, J.I. California Univ., San Francisco, CA )

    1991-08-01

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary.

  13. Accurate Satellite-Derived Estimates of Tropospheric Ozone Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Joiner, Joanna; Schoeberl, Mark R.; Vasilkov, Alexander P.; Oreopoulos, Lazaros; Platnick, Steven; Livesey, Nathaniel J.; Levelt, Pieternel F.

    2008-01-01

    Estimates of the radiative forcing due to anthropogenically-produced tropospheric O3 are derived primarily from models. Here, we use tropospheric ozone and cloud data from several instruments in the A-train constellation of satellites as well as information from the GEOS-5 Data Assimilation System to accurately estimate the instantaneous radiative forcing from tropospheric O3 for January and July 2005. We improve upon previous estimates of tropospheric ozone mixing ratios from a residual approach using the NASA Earth Observing System (EOS) Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) by incorporating cloud pressure information from OMI. Since we cannot distinguish between natural and anthropogenic sources with the satellite data, our estimates reflect the total forcing due to tropospheric O3. We focus specifically on the magnitude and spatial structure of the cloud effect on both the shortand long-wave radiative forcing. The estimates presented here can be used to validate present day O3 radiative forcing produced by models.

  14. Assessing uncertainty in published risk estimates using ...

    EPA Pesticide Factsheets

    Introduction: The National Research Council recommended quantitative evaluation of uncertainty in effect estimates for risk assessment. This analysis considers uncertainty across model forms and model parameterizations with hexavalent chromium [Cr(VI)] and lung cancer mortality as an example. The objective is to characterize model uncertainty by evaluating estimates across published epidemiologic studies of the same cohort.Methods: This analysis was based on 5 studies analyzing a cohort of 2,357 workers employed from 1950-74 in a chromate production plant in Maryland. Cox and Poisson models were the only model forms considered by study authors to assess the effect of Cr(VI) on lung cancer mortality. All models adjusted for smoking and included a 5-year exposure lag, however other latency periods and model covariates such as age and race were considered. Published effect estimates were standardized to the same units and normalized by their variances to produce a standardized metric to compare variability within and between model forms. A total of 5 similarly parameterized analyses were considered across model form, and 16 analyses with alternative parameterizations were considered within model form (10 Cox; 6 Poisson). Results: Across Cox and Poisson model forms, adjusted cumulative exposure coefficients (betas) for 5 similar analyses ranged from 2.47 to 4.33 (mean=2.97, σ2=0.63). Within the 10 Cox models, coefficients ranged from 2.53 to 4.42 (mean=3.29, σ2=0.

  15. Solar cosmic rays as a specific source of radiation risk during piloted space flight.

    PubMed

    Petrov, V M

    2004-01-01

    Solar cosmic rays present one of several radiation sources that are unique to space flight. Under ground conditions the exposure to individuals has a controlled form and radiation risk occurs as stochastic radiobiological effects. Existence of solar cosmic rays in space leads to a stochastic mode of radiation environment as a result of which any radiobiological consequences of exposure to solar cosmic rays during the flight will be probabilistic values. In this case, the hazard of deterministic effects should also be expressed in radiation risk values. The main deterministic effect under space conditions is radiation sickness. The best dosimetric functional for its analysis is the blood forming organs dose equivalent but not an effective dose. In addition, the repair processes in red bone marrow affect strongly on the manifestation of this pathology and they must be taken into account for radiation risk assessment. A method for taking into account the mentioned above peculiarities for the solar cosmic rays radiation risk assessment during the interplanetary flights is given in the report. It is shown that radiation risk of deterministic effects defined, as the death probability caused by radiation sickness due to acute solar cosmic rays exposure, can be comparable to risk of stochastic effects. Its value decreases strongly because of the fractional mode of exposure during the orbital movement of the spacecraft. On the contrary, during the interplanetary flight, radiation risk of deterministic effects increases significantly because of the residual component of the blood forming organs dose from previous solar proton events. The noted quality of radiation responses must be taken into account for estimating radiation hazard in space.

  16. Radiation release and health effects lessons from the Three Mile Island incident: assessment of objective risks for emergency preparedness planning

    SciTech Connect

    Berger, C.D.; Mynatt, F.R.

    1980-01-01

    The accepted theories of radiation health effects are briefly discussed so that the Three Mile Island health effects estimations can be better understood. The author recommends that emergency response planners weigh the objective risks rather than the perceived risks of low-level radiation against those associated with evacuation of large population zones before a final plan is put into effect. (ACR)

  17. IMPROVED RISK ESTIMATES FOR CARBON TETRACHLORIDE

    SciTech Connect

    Benson, Janet M.; Springer, David L.

    1999-12-31

    Carbon tetrachloride has been used extensively within the DOE nuclear weapons facilities. Rocky Flats was formerly the largest volume consumer of CCl4 in the United States using 5000 gallons in 1977 alone (Ripple, 1992). At the Hanford site, several hundred thousand gallons of CCl4 were discharged between 1955 and 1973 into underground cribs for storage. Levels of CCl4 in groundwater at highly contaminated sites at the Hanford facility have exceeded 8 the drinking water standard of 5 ppb by several orders of magnitude (Illman, 1993). High levels of CCl4 at these facilities represent a potential health hazard for workers conducting cleanup operations and for surrounding communities. The level of CCl4 cleanup required at these sites and associated costs are driven by current human health risk estimates, which assume that CCl4 is a genotoxic carcinogen. The overall purpose of these studies was to improve the scientific basis for assessing the health risk associated with human exposure to CCl4. Specific research objectives of this project were to: (1) compare the rates of CCl4 metabolism by rats, mice and hamsters in vivo and extrapolate those rates to man based on parallel studies on the metabolism of CCl4 by rat, mouse, hamster and human hepatic microsomes in vitro; (2) using hepatic microsome preparations, determine the role of specific cytochrome P450 isoforms in CCl4-mediated toxicity and the effects of repeated inhalation and ingestion of CCl4 on these isoforms; and (3) evaluate the toxicokinetics of inhaled CCl4 in rats, mice and hamsters. This information has been used to improve the physiologically based pharmacokinetic (PBPK) model for CCl4 originally developed by Paustenbach et al. (1988) and more recently revised by Thrall and Kenny (1996). Another major objective of the project was to provide scientific evidence that CCl4, like chloroform, is a hepatocarcinogen only when exposure results in cell damage, cell killing and regenerative proliferation. In

  18. How Safe Is Safe Enough? Radiation Risk for a Human Mission to Mars

    PubMed Central

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Chappell, Lori J.; Huff, Janice L.

    2013-01-01

    Astronauts on a mission to Mars would be exposed for up to 3 years to galactic cosmic rays (GCR) — made up of high-energy protons and high charge (Z) and energy (E) (HZE) nuclei. GCR exposure rate increases about three times as spacecraft venture out of Earth orbit into deep space where protection of the Earth's magnetosphere and solid body are lost. NASA's radiation standard limits astronaut exposures to a 3% risk of exposure induced death (REID) at the upper 95% confidence interval (CI) of the risk estimate. Fatal cancer risk has been considered the dominant risk for GCR, however recent epidemiological analysis of radiation risks for circulatory diseases allow for predictions of REID for circulatory diseases to be included with cancer risk predictions for space missions. Using NASA's models of risks and uncertainties, we predicted that central estimates for radiation induced mortality and morbidity could exceed 5% and 10% with upper 95% CI near 10% and 20%, respectively for a Mars mission. Additional risks to the central nervous system (CNS) and qualitative differences in the biological effects of GCR compared to terrestrial radiation may significantly increase these estimates, and will require new knowledge to evaluate. PMID:24146746

  19. How safe is safe enough? Radiation risk for a human mission to Mars.

    PubMed

    Cucinotta, Francis A; Kim, Myung-Hee Y; Chappell, Lori J; Huff, Janice L

    2013-01-01

    Astronauts on a mission to Mars would be exposed for up to 3 years to galactic cosmic rays (GCR)--made up of high-energy protons and high charge (Z) and energy (E) (HZE) nuclei. GCR exposure rate increases about three times as spacecraft venture out of Earth orbit into deep space where protection of the Earth's magnetosphere and solid body are lost. NASA's radiation standard limits astronaut exposures to a 3% risk of exposure induced death (REID) at the upper 95% confidence interval (CI) of the risk estimate. Fatal cancer risk has been considered the dominant risk for GCR, however recent epidemiological analysis of radiation risks for circulatory diseases allow for predictions of REID for circulatory diseases to be included with cancer risk predictions for space missions. Using NASA's models of risks and uncertainties, we predicted that central estimates for radiation induced mortality and morbidity could exceed 5% and 10% with upper 95% CI near 10% and 20%, respectively for a Mars mission. Additional risks to the central nervous system (CNS) and qualitative differences in the biological effects of GCR compared to terrestrial radiation may significantly increase these estimates, and will require new knowledge to evaluate.

  20. The economic costs of radiation-induced health effects: Estimation and simulation

    SciTech Connect

    Nieves, L.A.; Tawil, J.J.

    1988-08-01

    This effort improves the quantitative information available for use in evaluating actions that alter health risks due to population exposure to ionizing radiation. To project the potential future costs of changes in health effects risks, Pacific Northwest Laboratory (PNL) constructed a probabilistic computer model, Health Effects Costs Model (HECOM), which utilizes the health effect incidence estimates from accident consequences models to calculate the discounted sum of the economic costs associated with population exposure to ionizing radiation. Application of HECOM to value-impact and environmental impact analyses should greatly increase the quality of the information available for regulatory decision making. Three major types of health effects present risks for any population sustaining a significant radiation exposure: acute radiation injuries (and fatalities), latent cancers, and impairments due to genetic effects. The literature pertaining to both incidence and treatment of these health effects was reviewed by PNL and provided the basis for developing economic cost estimates. The economic costs of health effects estimated by HECOM represent both the value of resources consumed in diagnosing, treating, and caring for the patient and the value of goods not produced because of illness or premature death due to the health effect. Additional costs to society, such as pain and suffering, are not included in the PNL economic cost measures since they do not divert resources from other uses, are difficult to quantify, and do not have a value observable in the marketplace. 83 refs., 3 figs., 19 tabs.

  1. A review of some epidemiological studies on cancer risk from low-dose radiation or other carcinogenic agents.

    PubMed

    Ogata, Hiromitsu

    2011-07-01

    It is extremely difficult to assess cancer risks accurately due to health effects of low-dose radiation exposure or other carcinogens based on epidemiological studies. For the detection of minute increases of the risk at low-level exposure, most of epidemiological studies lack statistical power, and they involve various complicated confounding factors. This paper reports on a literature survey of epidemiological studies published since 2000 on cancer risks associated with low-dose radiation and other carcinogens to gather major epidemiological data. Integrated risk indices were derived from those data by using, where possible, statistical models. Regarding risk assessment of low-dose radiation exposure, it is important to lower the degree of uncertainty arising from risk estimation. Risk assessment of low-dose radiation exposure could be scientific evidence when uncertainty is considered in comparing carcinogenic risks of radiation with those of other carcinogens.

  2. Radiative Energy Budget Estimates for the 1979 Southwest Summer Monsoon.

    NASA Astrophysics Data System (ADS)

    Ackerman, Steven A.; Cox, Stephen K.

    1987-10-01

    Obsemations of temperature moisture, cloud amount, cloud height and soil-derived aerosols are incorporated into radiative transfer models to yield estimates of the tropospheric and surface radiative energy budgets for the summer Monsoon of 1979. Results are presented for six phases of the monsoon for the region 30°S to 40°N latitude and 30°E to 100°E longitude. The derived radiative fields are significantly different from climatological estimates. The evolution of the radiative energy budgets are discussed in relation to monsoon activity. Total tropospheric convergence (TTC) for the January and February phases exhibits a minimum cooling over the southern Indian Ocean and a maximum tropospheric radiative energy loss over the Arabian Sea and Bay of Bengal. The early May, pre-onset, onset and post-onset periods exhibit cellular patterns in TTC, with maximum cooling over the cloud-free oceanic regions, and minimum cooling associated with continental regions and areas with large amounts of cloud. This cellular structure is still evident when TTC is averaged over 10° regions. Large seasonal variations in TTC are observed over the deserts, due to the presence of dust in the summer. Regions with large seasonal variations in cloud cover (e.g., the Arabian Sea) also display large variations in TTC. Regionally averaged radiative heating profiles also change significantly with period. These variations result primarily from changes in the cloud distribution associated with the evolution of the monsoon.The net surface radiative flux varies markedly from period to period, and within the same period. As expected, all six periods have a maximum surface radiative energy gain for the cloud-free oceanic regions, while cloudy and continental regions tend to have relative minimae. Large spatial and temporal variations exist in the net surface flux.

  3. Risk communication, radiation, and radiological emergencies: strategies, tools, and techniques.

    PubMed

    Covello, Vincent T

    2011-11-01

    Risk communication is the two-way exchange of information about risks, including risks associated with radiation and radiological events. The risk communication literature contains a broad range of strategies for overcoming the psychological, sociological, and cultural factors that create public misperceptions and misunderstandings about risks. These strategies help radiation risk communicators overcome the challenges posed by three basic observations about people under stress: (1) people under stress typically want to know that you care before they care about what you know; (2) people under stress typically have difficulty hearing, understanding, and remembering information; (3) people under stress typically focus more on negative information than positive information.

  4. Cancer Risks Associated with External Radiation From Diagnostic Imaging Procedures

    PubMed Central

    Linet, Martha S.; Slovis, Thomas L.; Miller, Donald L.; Kleinerman, Ruth; Lee, Choonsik; Rajaraman, Preetha; de Gonzalez, Amy Berrington

    2012-01-01

    The 600% increase in medical radiation exposure to the US population since 1980 has provided immense benefit, but potential future cancer risks to patients. Most of the increase is from diagnostic radiologic procedures. The objectives of this review are to summarize epidemiologic data on cancer risks associated with diagnostic procedures, describe how exposures from recent diagnostic procedures relate to radiation levels linked with cancer occurrence, and propose a framework of strategies to reduce radiation from diagnostic imaging in patients. We briefly review radiation dose definitions, mechanisms of radiation carcinogenesis, key epidemiologic studies of medical and other radiation sources and cancer risks, and dose trends from diagnostic procedures. We describe cancer risks from experimental studies, future projected risks from current imaging procedures, and the potential for higher risks in genetically susceptible populations. To reduce future projected cancers from diagnostic procedures, we advocate widespread use of evidence-based appropriateness criteria for decisions about imaging procedures, oversight of equipment to deliver reliably the minimum radiation required to attain clinical objectives, development of electronic lifetime records of imaging procedures for patients and their physicians, and commitment by medical training programs, professional societies, and radiation protection organizations to educate all stakeholders in reducing radiation from diagnostic procedures. PMID:22307864

  5. Cancer risks associated with external radiation from diagnostic imaging procedures.

    PubMed

    Linet, Martha S; Slovis, Thomas L; Miller, Donald L; Kleinerman, Ruth; Lee, Choonsik; Rajaraman, Preetha; Berrington de Gonzalez, Amy

    2012-01-01

    The 600% increase in medical radiation exposure to the US population since 1980 has provided immense benefit, but increased potential future cancer risks to patients. Most of the increase is from diagnostic radiologic procedures. The objectives of this review are to summarize epidemiologic data on cancer risks associated with diagnostic procedures, describe how exposures from recent diagnostic procedures relate to radiation levels linked with cancer occurrence, and propose a framework of strategies to reduce radiation from diagnostic imaging in patients. We briefly review radiation dose definitions, mechanisms of radiation carcinogenesis, key epidemiologic studies of medical and other radiation sources and cancer risks, and dose trends from diagnostic procedures. We describe cancer risks from experimental studies, future projected risks from current imaging procedures, and the potential for higher risks in genetically susceptible populations. To reduce future projected cancers from diagnostic procedures, we advocate the widespread use of evidence-based appropriateness criteria for decisions about imaging procedures; oversight of equipment to deliver reliably the minimum radiation required to attain clinical objectives; development of electronic lifetime records of imaging procedures for patients and their physicians; and commitment by medical training programs, professional societies, and radiation protection organizations to educate all stakeholders in reducing radiation from diagnostic procedures.

  6. Radiation as a Risk Factor for Cardiovascular Disease

    PubMed Central

    Moulder, John E.; Hopewell, John W.

    2011-01-01

    Abstract Humans are continually exposed to ionizing radiation from terrestrial sources. The two major contributors to radiation exposure of the U.S. population are ubiquitous background radiation and medical exposure of patients. From the early 1980s to 2006, the average dose per individual in the United States for all sources of radiation increased by a factor of 1.7–6.2 mSv, with this increase due to the growth of medical imaging procedures. Radiation can place individuals at an increased risk of developing cardiovascular disease. Excess risk of cardiovascular disease occurs a long time after exposure to lower doses of radiation as demonstrated in Japanese atomic bomb survivors. This review examines sources of radiation (atomic bombs, radiation accidents, radiological terrorism, cancer treatment, space exploration, radiosurgery for cardiac arrhythmia, and computed tomography) and the risk for developing cardiovascular disease. The evidence presented suggests an association between cardiovascular disease and exposure to low-to-moderate levels of radiation, as well as the well-known association at high doses. Studies are needed to define the extent that diagnostic and therapeutic radiation results in increased risk factors for cardiovascular disease, to understand the mechanisms involved, and to develop strategies to mitigate or treat radiation-induced cardiovascular disease. Antioxid. Redox Signal. 15, 1945–1956. PMID:21091078

  7. A Biodosimeter for Multiparametric Determination of Radiation Dose, Radiation Quality, and Radiation Risk

    NASA Technical Reports Server (NTRS)

    Richmond, Robert; Cruz, Angela; Jansen, Heather; Bors, Karen

    2003-01-01

    Predicting risk of human cancer following exposure of an individual or a population to ionizing radiation is challenging. To an approximation, this is because uncertainties of uniform absorption of dose and the uniform processing of dose-related damage at the cellular level within a complex set of biological variables degrade the confidence of predicting the delayed expression of cancer as a relatively rare event. Cellular biodosimeters that simultaneously report: 1) the quantity of absorbed dose after exposure to ionizing radiation, 2) the quality of radiation delivering that dose, and 3) the risk of developing cancer by the cells absorbing that dose would therefore be useful. An approach to such a multiparametric biodosimeter will be reported. This is the demonstration of a dose responsive field effect of enhanced expression of keratin 18 (K18) in cultures of human mammary epithelial cells irradiated with cesium-1 37 gamma-rays. Dose response of enhanced K18 expression was experimentally extended over a range of 30 to 90 cGy for cells evaluated at mid-log phase. K18 has been reported to be a marker for tumor staging and for apoptosis, and thereby serves as an example of a potential marker for cancer risk, where the reality of such predictive value would require additional experimental development. Since observed radiogenic increase in expression of K18 is a field effect, ie., chronically present in all cells of the irradiated population, it may be hypothesized that K18 expression in specific cells absorbing particulate irradiation, such as the high-LET-producing atomic nuclei of space radiation, will report on both the single-cell distributions of those particles amongst cells within the exposed population, and that the relatively high dose per cell delivered by densely ionizing tracks of those intersecting particles will lead to cell-specific high-expression levels of K18, thereby providing analytical end points that may be used to resolve both the quantity and

  8. Non-analog Monte Carlo estimators for radiation momentum deposition

    SciTech Connect

    Densmore, Jeffery D; Hykes, Joshua M

    2008-01-01

    The standard method for calculating radiation momentum deposition in Monte Carlo simulations is the analog estimator, which tallies the change in a particle's momentum at each interaction with the matter. Unfortunately, the analog estimator can suffer from large amounts of statistical error. In this paper, we present three new non-analog techniques for estimating momentum deposition. Specifically, we use absorption, collision, and track-length estimators to evaluate a simple integral expression for momentum deposition that does not contain terms that can cause large amounts of statistical error in the analog scheme. We compare our new non-analog estimators to the analog estimator with a set of test problems that encompass a wide range of material properties and both isotropic and anisotropic scattering. In nearly all cases, the new non-analog estimators outperform the analog estimator. The track-length estimator consistently yields the highest performance gains, improving upon the analog-estimator figure of merit by factors of up to two orders of magnitude.

  9. Space radiation dose estimates on the surface of Mars.

    PubMed

    Simonsen, L C; Nealy, J E; Townsend, L W; Wilson, J W

    1990-01-01

    A future goal of the U.S. space program is a commitment to the manned exploration and habitation of Mars. An important consideration of such missions is the exposure of crew members to the damaging effects of ionizing radiation from high-energy galactic cosmic ray fluxes and solar proton flares. The crew will encounter the most harmful radiation environment in transit to Mars from which they must be adequately protected. However, once on the planet's surface, the Martian environment should provide a significant amount of protection from free-space radiative fluxes. In current Mars scenario descriptions, the crew flight time to Mars is estimated to be anywhere from 7 months to over a year each way, with stay times on the surface ranging from 20 days to 2 years. To maintain dose levels below established astronaut limits, dose estimates need to be determined for the entire mission length. With extended crew durations on the surface anticipated, the characterization of the Mars radiation environment is important in assessing all radiation protection requirements. This synopsis focuses on the probable doses incurred by surface inhabitants from the transport of galactic cosmic rays and solar protons through the Mars atmosphere.

  10. Space Radiation Risks for Astronauts on Multiple International Space Station Missions

    PubMed Central

    Cucinotta, Francis A.

    2014-01-01

    Mortality and morbidity risks from space radiation exposure are an important concern for astronauts participating in International Space Station (ISS) missions. NASA’s radiation limits set a 3% cancer fatality probability as the upper bound of acceptable risk and considers uncertainties in risk predictions using the upper 95% confidence level (CL) of the assessment. In addition to risk limitation, an important question arises as to the likelihood of a causal association between a crew-members’ radiation exposure in the past and a diagnosis of cancer. For the first time, we report on predictions of age and sex specific cancer risks, expected years of life-loss for specific diseases, and probability of causation (PC) at different post-mission times for participants in 1-year or multiple ISS missions. Risk projections with uncertainty estimates are within NASA acceptable radiation standards for mission lengths of 1-year or less for likely crew demographics. However, for solar minimum conditions upper 95% CL exceed 3% risk of exposure induced death (REID) by 18 months or 24 months for females and males, respectively. Median PC and upper 95%-confidence intervals are found to exceed 50% for several cancers for participation in two or more ISS missions of 18 months or longer total duration near solar minimum, or for longer ISS missions at other phases of the solar cycle. However, current risk models only consider estimates of quantitative differences between high and low linear energy transfer (LET) radiation. We also make predictions of risk and uncertainties that would result from an increase in tumor lethality for highly ionizing radiation reported in animal studies, and the additional risks from circulatory diseases. These additional concerns could further reduce the maximum duration of ISS missions within acceptable risk levels, and will require new knowledge to properly evaluate. PMID:24759903

  11. Space radiation risks for astronauts on multiple International Space Station missions.

    PubMed

    Cucinotta, Francis A

    2014-01-01

    Mortality and morbidity risks from space radiation exposure are an important concern for astronauts participating in International Space Station (ISS) missions. NASA's radiation limits set a 3% cancer fatality probability as the upper bound of acceptable risk and considers uncertainties in risk predictions using the upper 95% confidence level (CL) of the assessment. In addition to risk limitation, an important question arises as to the likelihood of a causal association between a crew-members' radiation exposure in the past and a diagnosis of cancer. For the first time, we report on predictions of age and sex specific cancer risks, expected years of life-loss for specific diseases, and probability of causation (PC) at different post-mission times for participants in 1-year or multiple ISS missions. Risk projections with uncertainty estimates are within NASA acceptable radiation standards for mission lengths of 1-year or less for likely crew demographics. However, for solar minimum conditions upper 95% CL exceed 3% risk of exposure induced death (REID) by 18 months or 24 months for females and males, respectively. Median PC and upper 95%-confidence intervals are found to exceed 50% for several cancers for participation in two or more ISS missions of 18 months or longer total duration near solar minimum, or for longer ISS missions at other phases of the solar cycle. However, current risk models only consider estimates of quantitative differences between high and low linear energy transfer (LET) radiation. We also make predictions of risk and uncertainties that would result from an increase in tumor lethality for highly ionizing radiation reported in animal studies, and the additional risks from circulatory diseases. These additional concerns could further reduce the maximum duration of ISS missions within acceptable risk levels, and will require new knowledge to properly evaluate.

  12. Improvement of Risk Assessment from Space Radiation Exposure for Future Space Exploration Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Atwell, Bill; Ponomarev, Artem L.; Nounu, Hatem; Hussein, Hesham; Cucinotta, Francis A.

    2007-01-01

    Protecting astronauts from space radiation exposure is an important challenge for mission design and operations for future exploration-class and long-duration missions. Crew members are exposed to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR). If sufficient protection is not provided the radiation risk to crew members from SPEs could be significant. To improve exposure risk estimates and radiation protection from SPEs, detailed variations of radiation shielding properties are required. A model using a modern CAD tool ProE (TM), which is the leading engineering design platform at NASA, has been developed for this purpose. For the calculation of radiation exposure at a specific site, the cosine distribution was implemented to replicate the omnidirectional characteristic of the 4 pi particle flux on a surface. Previously, estimates of doses to the blood forming organs (BFO) from SPEs have been made using an average body-shielding distribution for the bone marrow based on the computerized anatomical man model (CAM). The development of an 82-point body-shielding distribution at BFOs made it possible to estimate the mean and variance of SPE doses in the major active marrow regions. Using the detailed distribution of bone marrow sites and implementation of cosine distribution of particle flux is shown to provide improved estimates of acute and cancer risks from SPEs.

  13. A meta-analysis of leukaemia risk from protracted exposure to low-dose gamma radiation

    PubMed Central

    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. PubMed and Embase databases were searched for additional occupational and environmental studies published between 2005 and 2009. Study selection We selected 23 studies that: (1) examined the association between protracted exposures to ionising radiation and leukaemia excluding chronic lymphocytic subtype; (2) were a cohort or nested case–control design without major bias; (3) reported quantitative estimates of exposure; and (4) conducted exposure–response analyses using relative or excess RR per unit exposure. Methods Studies were further screened to reduce information overlap. Random effects models were developed to summarise between-study variance and obtain an aggregate estimate of the excess RR at 100 mGy. Publication bias was assessed by trim and fill and Rosenthal's file drawer methods. Results We found an ERR at 100 mGy of 0.19 (95% CI 0.07 to 0.32) by modelling results from 10 studies and adjusting for publication bias. Between-study variance was not evident (p=0.99). Conclusions Protracted exposure to low-dose gamma radiation is significantly associated with leukaemia. Our estimate agreed well with the leukaemia risk observed among exposed adults in the Life Span Study (LSS) of atomic bomb survivors, providing increased confidence in the current understanding of leukaemia risk from ionising radiation. However, unlike the estimates obtained from the LSS, our model provides a precise, quantitative summary of the direct estimates of excess risk from studies of

  14. Space life sciences: radiation risk assessment and radiation measurements in low Earth orbit.

    PubMed

    2004-01-01

    The volume contains papers presented at COSPAR symposia in October 2002 about radiation risk assessment and radiation measurements in low Earth orbit. The risk assessment symposium brought together multidisciplinary expertise including physicists, biologists, and theoretical modelers. Topics included current knowledge about known and predicted radiation environments, radiation shielding, physics cross section models, improved ion beam transport codes, biological demonstrations of specific shielding materials and applications to a manned mission to Mars, advancements in biological measurement of radiation-induced protein expression profiles, and integration of physical and biological parameters to assess key elements of radiation risk. Papers from the radiation measurements in low Earth orbit symposium included data about dose, linear energy transfer spectra, and charge spectra from recent measurements on the International Space Station (ISS), comparison between calculations and measurements of dose distribution inside a human phantom and the neutron component inside the ISS; and reviews of trapped antiprotons and positrons inside the Earth's magnetosphere.

  15. Space radiation risks to the central nervous system

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis A.; Alp, Murat; Sulzman, Frank M.; Wang, Minli

    2014-07-01

    Central nervous system (CNS) risks which include during space missions and lifetime risks due to space radiation exposure are of concern for long-term exploration missions to Mars or other destinations. Possible CNS risks during a mission are altered cognitive function, including detriments in short-term memory, reduced motor function, and behavioral changes, which may affect performance and human health. The late CNS risks are possible neurological disorders such as premature aging, and Alzheimer's disease (AD) or other dementia. Radiation safety requirements are intended to prevent all clinically significant acute risks. However the definition of clinically significant CNS risks and their dependences on dose, dose-rate and radiation quality is poorly understood at this time. For late CNS effects such as increased risk of AD, the occurrence of the disease is fatal with mean time from diagnosis of early stage AD to death about 8 years. Therefore if AD risk or other late CNS risks from space radiation occur at mission relevant doses, they would naturally be included in the overall acceptable risk of exposure induced death (REID) probability for space missions. Important progress has been made in understanding CNS risks due to space radiation exposure, however in general the doses used in experimental studies have been much higher than the annual galactic cosmic ray (GCR) dose (∼0.1 Gy/y at solar maximum and ∼0.2 Gy/y at solar minimum with less than 50% from HZE particles). In this report we summarize recent space radiobiology studies of CNS effects from particle accelerators simulating space radiation using experimental models, and make a critical assessment of their relevance relative to doses and dose-rates to be incurred on a Mars mission. Prospects for understanding dose, dose-rate and radiation quality dependencies of CNS effects and extrapolation to human risk assessments are described.

  16. Radiation shielding estimates for manned Mars space flight.

    PubMed

    Dudkin, V E; Kovalev, E E; Kolomensky, A V; Sakovich, V A; Semenov, V F; Demin, V P; Benton, E V

    1992-01-01

    In the analysis of the required radiation shielding protection of spacecraft during a Mars flight, specific effects of solar activity (SA) on the intensity of galactic and solar cosmic rays were taken into consideration. Three spaceflight periods were considered: (1) maximum SA; (2) minimum SA; and (3) intermediate SA, when intensities of both galactic and solar cosmic rays are moderately high. Scenarios of spaceflights utilizing liquid-propellant rocket engines, low- and intermediate-thrust nuclear electrojet engines, and nuclear rocket engines, all of which have been designed in the Soviet Union, are reviewed. Calculations were performed on the basis of a set of standards for radiation protection approved by the U.S.S.R. State Committee for Standards. It was found that the lowest estimated mass of a Mars spacecraft, including the radiation shielding mass, obtained using a combination of a liquid propellant engine with low and intermediate thrust nuclear electrojet engines, would be 500-550 metric tons.

  17. Concepts and challenges in cancer risk prediction for the space radiation environment

    NASA Astrophysics Data System (ADS)

    Barcellos-Hoff, Mary Helen; Blakely, Eleanor A.; Burma, Sandeep; Fornace, Albert J.; Gerson, Stanton; Hlatky, Lynn; Kirsch, David G.; Luderer, Ulrike; Shay, Jerry; Wang, Ya; Weil, Michael M.

    2015-07-01

    Cancer is an important long-term risk for astronauts exposed to protons and high-energy charged particles during travel and residence on asteroids, the moon, and other planets. NASA's Biomedical Critical Path Roadmap defines the carcinogenic risks of radiation exposure as one of four type I risks. A type I risk represents a demonstrated, serious problem with no countermeasure concepts, and may be a potential "show-stopper" for long duration spaceflight. Estimating the carcinogenic risks for humans who will be exposed to heavy ions during deep space exploration has very large uncertainties at present. There are no human data that address risk from extended exposure to complex radiation fields. The overarching goal in this area to improve risk modeling is to provide biological insight and mechanistic analysis of radiation quality effects on carcinogenesis. Understanding mechanisms will provide routes to modeling and predicting risk and designing countermeasures. This white paper reviews broad issues related to experimental models and concepts in space radiation carcinogenesis as well as the current state of the field to place into context recent findings and concepts derived from the NASA Space Radiation Program.

  18. Concepts and challenges in cancer risk prediction for the space radiation environment.

    PubMed

    Barcellos-Hoff, Mary Helen; Blakely, Eleanor A; Burma, Sandeep; Fornace, Albert J; Gerson, Stanton; Hlatky, Lynn; Kirsch, David G; Luderer, Ulrike; Shay, Jerry; Wang, Ya; Weil, Michael M

    2015-07-01

    Cancer is an important long-term risk for astronauts exposed to protons and high-energy charged particles during travel and residence on asteroids, the moon, and other planets. NASA's Biomedical Critical Path Roadmap defines the carcinogenic risks of radiation exposure as one of four type I risks. A type I risk represents a demonstrated, serious problem with no countermeasure concepts, and may be a potential "show-stopper" for long duration spaceflight. Estimating the carcinogenic risks for humans who will be exposed to heavy ions during deep space exploration has very large uncertainties at present. There are no human data that address risk from extended exposure to complex radiation fields. The overarching goal in this area to improve risk modeling is to provide biological insight and mechanistic analysis of radiation quality effects on carcinogenesis. Understanding mechanisms will provide routes to modeling and predicting risk and designing countermeasures. This white paper reviews broad issues related to experimental models and concepts in space radiation carcinogenesis as well as the current state of the field to place into context recent findings and concepts derived from the NASA Space Radiation Program.

  19. Acceptability of risk from radiation: Application to human space flight

    SciTech Connect

    1997-04-30

    This one of NASA`s sponsored activities of the NCRP. In 1983, NASA asked NCRP to examine radiation risks in space and to make recommendations about career radiation limits for astronauts (with cancer considered as the principal risk). In conjunction with that effort, NCRP was asked to convene this symposium; objective is to examine the technical, strategic, and philosophical issues pertaining to acceptable risk and radiation in space. Nine papers are included together with panel discussions and a summary. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  20. Estimation of scattered radiation in digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Diaz, O.; Dance, D. R.; Young, K. C.; Elangovan, P.; Bakic, P. R.; Wells, K.

    2014-08-01

    Digital breast tomosynthesis (DBT) is a promising technique to overcome the tissue superposition limitations found in planar 2D x-ray mammography. However, as most DBT systems do not employ an anti-scatter grid, the levels of scattered radiation recorded within the image receptor are significantly higher than that observed in planar 2D x-ray mammography. Knowledge of this field is necessary as part of any correction scheme and for computer modelling and optimisation of this examination. Monte Carlo (MC) simulations are often used for this purpose, however they are computationally expensive and a more rapid method of calculation is desirable. This issue is addressed in this work by the development of a fast kernel-based methodology for scatter field estimation using a detailed realistic DBT geometry. Thickness-dependent scatter kernels, which were validated against the literature with a maximum discrepancy of 4% for an idealised geometry, have been calculated and a new physical parameter (air gap distance) was used to estimate more accurately the distribution of scattered radiation for a series of anthropomorphic breast phantom models. The proposed methodology considers, for the first time, the effects of scattered radiation from the compression paddle and breast support plate, which can represent more than 30% of the total scattered radiation recorded within the image receptor. The results show that the scatter field estimator can calculate scattered radiation images in an average of 80 min for projection angles up to 25° with equal to or less than a 10% error across most of the breast area when compared with direct MC simulations.

  1. Perspectives on radiation dose estimates for A-bomb survivors

    SciTech Connect

    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.

  2. Estimating worldwide solar radiation resources on a 40km grid

    SciTech Connect

    Maxwell, E.L.; George, R.L.; Brady, E.H.

    1996-11-01

    During 1995, the National Renewable Energy Laboratory (NREL), initiated the Data Grid Task under the auspices of DOE`s Resource Assessment Program. A data grid is a framework of uniformly spaced locations (grid points) for which data are available. Estimates of monthly averages of direct normal, diffuse horizontal, and global horizontal daily-total solar radiation energy (kWh/m{sup 2}) are being made for each point on a grid covering the US, Mexico, the Caribbean, and southern Canada. The grid points are separated by approximately 40 km. Using interpolation methods, the digital data grid can be used to estimate solar resources at any location. The most encouraging result to date has been the location of sources providing worldwide data for most of the input parameters required for modeling daily total solar radiation. This is a multiyear task expected to continue through the rest of this century.

  3. Surface daytime net radiation estimation using artificial neural networks

    DOE PAGES

    Jiang, Bo; Zhang, Yi; Liang, Shunlin; ...

    2014-11-11

    Net all-wave surface radiation (Rn) is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN) models (general regression neural networks (GRNN) and Neuroet) to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991–2010more » both in global mode (all data were used to fit the models) and in conditional mode (the data were divided into four subsets and the models were fitted separately). Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R2) of 0.92, a root mean square error (RMSE) of 34.27 W·m–2 , and a bias of –0.61 W·m–2 in global mode based on the validation dataset. In conclusion, ANN methods are a potentially powerful tool for global Rn estimation.« less

  4. [Radiation safety provisions in a piloted mission to Mars based on calculated risks of overdose behind shielding].

    PubMed

    Shafirkin, A V; Kolomenskiĭ, A V; Petrov, V M

    2007-01-01

    The article deals with the prime sources of radiation hazard in a mission to Mars, compares the radiation risk values in flight and over the life span with consideration for various shielding thicknesses in habitable compartments and radiation shelter, and estimates possible life shortening. Given the stochastic nature of solar cosmic rays effects in a two-year mission and probability of powerful solar proton events, calculated were not only the mean tissue-equivalent doses behind various thickness of the shelter but also probability of their violation, risks of immediate and delayed radiation consequences and conceivable approaches to risk mitigation.

  5. Changes in biomarkers from space radiation may reflect dose not risk

    NASA Astrophysics Data System (ADS)

    Brooks, Antone L.; Lei, Xingye C.; Rithidech, Kanokporn

    the shape of the dose response to the reference radiation than it is on the radiation type of interest.A large study using micronuclei as biomarkers following exposure to different energies of mono-energetic neutrons, x-rays and gamma rays delivered at very low doses (0.0 to 0.10 Gy) is reported. As additional biomarkers of risk involved in critical steps in the carcinogenic process are developed, it may become possible to base risk estimates on biological change rather than the radiation energy deposition or dose.

  6. Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment

    SciTech Connect

    Blaylock, B.G.; Frank, M.L.; O`Neal, B.R.

    1993-08-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy`s (DOE`s) recommended dose rate limit of 0.4 mGy h{sup {minus}1} (1 rad d{sup {minus}1}). A dose rate no greater than 0.4 mGy h{sup {minus}1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE`s recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h{sup {minus}1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted.

  7. The potential impact of bystander effects on radiation risks in a Mars mission

    NASA Technical Reports Server (NTRS)

    Brenner, D. J.; Elliston, C. D.; Hall, E. I. (Principal Investigator)

    2001-01-01

    Densely ionizing (high-LET) galactic cosmic rays (GCR) contribute a significant component of the radiation risk in free space. Over a period of a few months-sufficient for the early stages of radiation carcinogenesis to occur-a significant proportion of cell nuclei will not be traversed. There is convincing evidence, at least in vitro, that irradiated cells can send out signals that can result in damage to nearby unirradiated cells. This observation can hold even when the unirradiated cells have been exposed to low doses of low-LET radiation. We discuss here a quantitative model based on the a formalism, an approach that incorporates radiobiological damage both from a bystander response to signals emitted by irradiated cells, and also from direct traversal of high-LET radiations through cell nuclei. The model produces results that are consistent with those of a series of studies of the bystander phenomenon using a high-LET microbeam, with the end point of in vitro oncogenic transformation. According to this picture, for exposure to high-LET particles such as galactic cosmic rays other than protons, the bystander effect is significant primarily at low fluences, i.e., exposures where there are significant numbers of untraversed cells. If the mechanisms postulated here were applicable in vivo, using a linear extrapolation of risks derived from studies using intermediate doses of high-LET radiation (where the contribution of the bystander effect may be negligible) to estimate risks at very low doses (where the bystander effect may be dominant) could underestimate the true risk from low doses of high-LET radiation. It would be highly premature simply to abandon current risk projections for high-LET, low-dose radiation; however, these considerations would suggest caution in applying results derived from experiments using high-LET radiation at fluences above approximately 1 particle per nucleus to risk estimation for a Mars mission.

  8. Physical and biomedical countermeasures for space radiation risk.

    PubMed

    Durante, Marco

    2008-01-01

    Radiation exposure represents a serious hindrance for long-term interplanetary missions because of the high uncertainty on risk coefficients, and to the lack of simple countermeasures. Even if uncertainties in risk assessment will be reduced in the next few years, there is little doubt that appropriate countermeasures have to be taken to reduce the exposure or the biological damage produced by cosmic radiation. In addition, it is necessary to provide effective countermeasures against solar particle events, which can produce acute effects, even life threatening, for inadequately protected crews. Strategies that may prove to be effective in reducing exposure, or the effects of the irradiation, include shielding, administration of drugs or dietary supplements to reduce the radiation effects, crew selection based on a screening of individual radiation sensitivity. It is foreseeable that research in passive and active radiation shielding, radioprotective chemicals, and individual susceptibility will boost in the next years to provide efficient countermeasures to the space radiation threat.

  9. Radiation-induced liver disease in three-dimensional conformal radiation therapy for primary liver carcinoma: The risk factors and hepatic radiation tolerance

    SciTech Connect

    Liang Shixiong; Zhu Xiaodong; Xu Zhiyong

    2006-06-01

    Purpose: To identify risk factors relevant to radiation-induced liver disease (RILD) and to determine the hepatic tolerance to radiation. Methods and Materials: The data of 109 primary liver carcinomas (PLC) treated with hypofractionated three-dimensional conformal radiation therapy (3D-CRT) were analyzed. Seventeen patients were diagnosed with RILD and 13 of 17 died of it. Results: The risk factors for RILD were late T stage, large gross tumor volume, presence of portal vein thrombosis, association with Child-Pugh Grade B cirrhosis, and acute hepatic toxicity. Multivariate analyses demonstrated that the severity of hepatic cirrhosis was a unique independent predictor. For Child-Pugh Grade A patients, the hepatic radiation tolerance was as follows: (1) Mean dose to normal liver (MDTNL) of 23 Gy was tolerable. (2) For cumulative dose-volume histogram, the tolerable volume percentages would be less than: V{sub 5} of 86%, V{sub 1} of 68%, V{sub 15} of 59%, V{sub 2} of 49%, V{sub 25} of 35%, V{sub 3} of 28%, V{sub 35} of 25%, and V{sub 4} of 20%. (3) Tolerable MDTNL could be estimated by MDTNL (Gy) = -1.686 + 0.023 * normal liver volume (cm{sup 3}). Conclusion: The predominant risk factor for RILD was the severity of hepatic cirrhosis. The hepatic tolerance to radiation could be estimated by dosimetric parameters.

  10. Imaging Radiation Doses and Associated Risks and Benefits in Subjects Participating in Breast Cancer Clinical Trials

    PubMed Central

    Spera, Gonzalo; Meyer, Carlos; Cabral, Pablo; Mackey, John R.

    2015-01-01

    Background. Medical imaging is commonly required in breast cancer (BC) clinical trials to assess the efficacy and/or safety of study interventions. Despite the lack of definitive epidemiological data linking imaging radiation with cancer development in adults, concerns exist about the risks of imaging radiation-induced malignancies (IRIMs) in subjects exposed to repetitive imaging. We estimated the imaging radiation dose and IRIM risk in subjects participating in BC trials. Materials and Methods. The imaging protocol requirements in 10 phase III trials in the adjuvant and advanced settings were assessed to estimate the effective radiation dose received by a typical and fully compliant subject in each trial. For each study, the excess lifetime attributable cancer risk (LAR) was calculated using the National Cancer Institute’s Radiation Risk Assessment Tool, version 3.7.1. Dose and risk calculations were performed for both imaging intensive and nonintensive approaches to reflect the variability in imaging performed within the studies. Results. The total effective imaging radiation dose was 0.4–262.2 mSv in adjuvant trials and 26–241.3 mSv in metastatic studies. The dose variability resulted from differing protocol requirements and imaging intensity approaches, with computed tomography, multigated acquisition scans, and bone scans as the major contributors. The mean LAR was 1.87–2,410/100,000 in adjuvant trials (IRIM: 0.0002%–2.41% of randomized subjects) and 6.9–67.3/100,000 in metastatic studies (IRIM: 0.007%–0.067% of subjects). Conclusion. IRIMs are infrequent events. In adjuvant trials, aligning the protocol requirements with the clinical guidelines’ surveillance recommendations and substituting radiating procedures with equivalent nonradiating ones would reduce IRIM risk. No significant risk has been observed in metastatic trials, and potential concerns on IRIMs are not justified. Implications for Practice: Medical imaging is key in breast cancer

  11. Cancer Risk Assessment for Space Radiation

    NASA Technical Reports Server (NTRS)

    Richmond, Robert C.; Cruz, Angela; Bors, Karen; Curreri, Peter A. (Technical Monitor)

    2001-01-01

    Predicting the occurrence of human cancer following exposure to any agent causing genetic damage is a difficult task. This is because the uncertainty of uniform exposure to the damaging agent, and the uncertainty of uniform processing of that damage within a complex set of biological variables, degrade the confidence of predicting the delayed expression of cancer as a relatively rare event within any given clinically normal individual. The radiation health research priorities for enabling long-duration human exploration of space were established in the 1996 NRC Report entitled 'Radiation Hazards to Crews of Interplanetary Missions: Biological Issues and Research Strategies'. This report emphasized that a 15-fold uncertainty in predicting radiation-induced cancer incidence must be reduced before NASA can commit humans to extended interplanetary missions. That report concluded that the great majority of this uncertainty is biologically based, while a minority is physically based due to uncertainties in radiation dosimetry and radiation transport codes. Since that report, the biologically based uncertainty has remained large, and the relatively small uncertainty associated with radiation dosimetry has increased due to the considerations raised by concepts of microdosimetry. In a practical sense, however, the additional uncertainties introduced by microdosimetry are encouraging since they are in a direction of lowered effective dose absorbed through infrequent interactions of any given cell with the high energy particle component of space radiation. Additional information is contained in the original extended abstract.

  12. Risk of cancer subsequent to low-dose radiation

    SciTech Connect

    Warren, S.

    1980-01-01

    The author puts low dose irradiation risks in perspective using average background radiation doses for standards. He assailed irresponsible media coverage during the height of public interest in the Three-Mile Island Reactor incident. (PCS)

  13. A New Approach to Reduce Uncertainties in Space Radiation Cancer Risk Predictions

    PubMed Central

    Cucinotta, Francis A.

    2015-01-01

    The prediction of space radiation induced cancer risk carries large uncertainties with two of the largest uncertainties being radiation quality and dose-rate effects. In risk models the ratio of the quality factor (QF) to the dose and dose-rate reduction effectiveness factor (DDREF) parameter is used to scale organ doses for cosmic ray proton and high charge and energy (HZE) particles to a hazard rate for γ-rays derived from human epidemiology data. In previous work, particle track structure concepts were used to formulate a space radiation QF function that is dependent on particle charge number Z, and kinetic energy per atomic mass unit, E. QF uncertainties where represented by subjective probability distribution functions (PDF) for the three QF parameters that described its maximum value and shape parameters for Z and E dependences. Here I report on an analysis of a maximum QF parameter and its uncertainty using mouse tumor induction data. Because experimental data for risks at low doses of γ-rays are highly uncertain which impacts estimates of maximum values of relative biological effectiveness (RBEmax), I developed an alternate QF model, denoted QFγAcute where QFs are defined relative to higher acute γ-ray doses (0.5 to 3 Gy). The alternate model reduces the dependence of risk projections on the DDREF, however a DDREF is still needed for risk estimates for high-energy protons and other primary or secondary sparsely ionizing space radiation components. Risk projections (upper confidence levels (CL)) for space missions show a reduction of about 40% (CL∼50%) using the QFγAcute model compared the QFs based on RBEmax and about 25% (CL∼35%) compared to previous estimates. In addition, I discuss how a possible qualitative difference leading to increased tumor lethality for HZE particles compared to low LET radiation and background tumors remains a large uncertainty in risk estimates. PMID:25789764

  14. A new approach to reduce uncertainties in space radiation cancer risk predictions.

    PubMed

    Cucinotta, Francis A

    2015-01-01

    The prediction of space radiation induced cancer risk carries large uncertainties with two of the largest uncertainties being radiation quality and dose-rate effects. In risk models the ratio of the quality factor (QF) to the dose and dose-rate reduction effectiveness factor (DDREF) parameter is used to scale organ doses for cosmic ray proton and high charge and energy (HZE) particles to a hazard rate for γ-rays derived from human epidemiology data. In previous work, particle track structure concepts were used to formulate a space radiation QF function that is dependent on particle charge number Z, and kinetic energy per atomic mass unit, E. QF uncertainties where represented by subjective probability distribution functions (PDF) for the three QF parameters that described its maximum value and shape parameters for Z and E dependences. Here I report on an analysis of a maximum QF parameter and its uncertainty using mouse tumor induction data. Because experimental data for risks at low doses of γ-rays are highly uncertain which impacts estimates of maximum values of relative biological effectiveness (RBEmax), I developed an alternate QF model, denoted QFγAcute where QFs are defined relative to higher acute γ-ray doses (0.5 to 3 Gy). The alternate model reduces the dependence of risk projections on the DDREF, however a DDREF is still needed for risk estimates for high-energy protons and other primary or secondary sparsely ionizing space radiation components. Risk projections (upper confidence levels (CL)) for space missions show a reduction of about 40% (CL∼50%) using the QFγAcute model compared the QFs based on RBEmax and about 25% (CL∼35%) compared to previous estimates. In addition, I discuss how a possible qualitative difference leading to increased tumor lethality for HZE particles compared to low LET radiation and background tumors remains a large uncertainty in risk estimates.

  15. Space radiation risk limits and Earth-Moon-Mars environmental models

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis A.; Hu, Shaowen; Schwadron, Nathan A.; Kozarev, K.; Townsend, Lawrence W.; Kim, Myung-Hee Y.

    2010-12-01

    We review NASA's short-term and career radiation limits for astronauts and methods for their application to future exploration missions outside of low Earth orbit. Career limits are intended to restrict late occurring health effects and include a 3% risk of exposure-induced death from cancer and new limits for central nervous system and heart disease risks. Short-term dose limits are used to prevent in-flight radiation sickness or death through restriction of the doses to the blood forming organs and to prevent clinically significant cataracts or skin damage through lens and skin dose limits, respectively. Large uncertainties exist in estimating the health risks of space radiation, chiefly the understanding of the radiobiology of heavy ions and dose rate and dose protraction effects, and the limitations in human epidemiology data. To protect against these uncertainties NASA estimates the 95% confidence in the cancer risk projection intervals as part of astronaut flight readiness assessments and mission design. Accurate organ dose and particle spectra models are needed to ensure astronauts stay below radiation limits and to support the goal of narrowing the uncertainties in risk projections. Methodologies for evaluation of space environments, radiation quality, and organ doses to evaluate limits are discussed, and current projections for lunar and Mars missions are described.

  16. Time-dependent radiation dose estimations during interplanetary space flights

    NASA Astrophysics Data System (ADS)

    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 treatment for patients with intermediate-risk prostate cancer

    PubMed Central

    Mayadev, Jyoti S.; Valicenti, Richard K.

    2012-01-01

    Around 70% of men presenting with prostate cancer will have organ-confined disease, with the majority presenting with low- or intermediate-risk prostate cancer. This article reviews the evidence supporting the current standard of care in radiation oncology for the evaluation and management of men with intermediate-risk prostate cancer. Dose escalation, hormonal therapy, combined modality therapy, and modern techniques for the delivery of radiation therapy are reviewed. PMID:22654963

  18. Risks of radiation cataracts from interplanetary space missions.

    PubMed

    Lett, J T; Lee, A C; Cox, A B

    1994-11-01

    Recognition of the human risks from radiation exposure during manned missions in deep space has been fostered by international co-operation; interagency collaboration is facilitating their evaluation. Further co-operation can lead, perhaps by the end of this decade, to an evaluation of one of the three major risks, namely radiation cataractogenesis, sufficient for use in the planning of the manned mission to Mars.

  19. What Are the Radiation Risks from CT?

    MedlinePlus

    ... by some of the Japanese survivors of the atomic bombs. These survivors, who are estimated to have experienced ... by some of the Japanese survivors of the atomic bombs. These survivors, who are estimated to have experienced ...

  20. Estimation of Fire Radiative Energy in Siberia Using MODIS Data

    NASA Astrophysics Data System (ADS)

    Shvetsov, Eugene; Ponomarev, Evgenii

    2014-05-01

    The intensity of heat release during biomass combustion is an important characteristic of wildfires. Space-borne systems, such as MODIS radiometer, provide observations of fire locations, as well as an estimate of the amount of radiant energy emitted by the fire. Such measures of fire radiative power (FRP) provide information on the fireline heat release intensity and on the rate of biomass combustion in large scale and are important for the analysis of fire impact on vegetation. In this study we analyzed the spatial distribution and temporal dynamics of detected wildfires in Siberia considering their radiative power. For the analysis we used database of fire detections made by MODIS instrument located on TERRA and AQUA satellites for 2002- 2013. For the detected fire pixels the frequency of their occurrence was calculated depending on the radiative power. More than 80% of all detected pixels had radiative power less than 100 MW. The distribution of fires according to their radiative power values was obtained for different regions of Siberia characterized by various vegetation and climatic conditions. Geospatial analysis performed using vegetation maps for the territory of Siberia and GIS layers of active fire detections showed that fires in deciduous and pine forests generally had lower intensities than fires in larch and spruce/fir forests. The rate of biomass combustion and the amount of heat emitted are strongly related to fuel moisture and therefore to weather conditions. In this study weather conditions were characterized using Russian and Canadian weather fire danger indices. Using images obtained during day and night satellite passes daily and long-term dynamics of fire radiative power was calculated. The long-term dynamics of fire radiative power measured by MODIS sensor was compared to weather fire danger indices calculated using on-ground weather stations data located in several Siberian regions mostly liable to fires. For most of the weather stations

  1. Effects of IL-10 haplotype and atomic bomb radiation exposure on gastric cancer risk.

    PubMed

    Hayashi, Tomonori; Ito, Reiko; Cologne, John; Maki, Mayumi; Morishita, Yukari; Nagamura, Hiroko; Sasaki, Keiko; Hayashi, Ikue; Imai, Kazue; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Kusunoki, Yoichiro; Ohishi, Waka; Fujiwara, Saeko; Akahoshi, Masazumi; Nakachi, Kei

    2013-07-01

    Gastric cancer (GC) is one of the cancers that reveal increased risk of mortality and incidence in atomic bomb survivors. The incidence of gastric cancer in the Life Span Study cohort of the Radiation Effects Research Foundation (RERF) increased with radiation dose (gender-averaged excess relative risk per Gy = 0.28) and remains high more than 65 years after exposure. To assess a possible role of gene-environment interaction, we examined the dose response for gastric cancer incidence based on immunosuppression-related IL-10 genotype, in a cohort study with 200 cancer cases (93 intestinal, 96 diffuse and 11 other types) among 4,690 atomic bomb survivors participating in an immunological substudy. Using a single haplotype block composed of four haplotype-tagging SNPs (comprising the major haplotype allele IL-10-ATTA and the minor haplotype allele IL-10-GGCG, which are categorized by IL-10 polymorphisms at -819A>G and -592T>G, +1177T>C and +1589A>G), multiplicative and additive models for joint effects of radiation and this IL-10 haplotyping were examined. The IL-10 minor haplotype allele(s) was a risk factor for intestinal type gastric cancer but not for diffuse type gastric cancer. Radiation was not associated with intestinal type gastric cancer. In diffuse type gastric cancer, the haplotype-specific excess relative risk (ERR) for radiation was statistically significant only in the major homozygote category of IL-10 (ERR = 0.46/Gy, P = 0.037), whereas estimated ERR for radiation with the minor IL-10 homozygotes was close to 0 and nonsignificant. Thus, the minor IL-10 haplotype might act to reduce the radiation related risk of diffuse-type gastric cancer. The results suggest that this IL-10 haplotyping might be involved in development of radiation-associated gastric cancer of the diffuse type, and that IL-10 haplotypes may explain individual differences in the radiation-related risk of gastric cancer.

  2. Risk and survival outcomes of radiation-induced CNS tumors.

    PubMed

    Lee, Jessica W; Wernicke, A Gabriella

    2016-08-01

    Patients treated with cranial radiation are at risk of developing secondary CNS tumors. Understanding the incidence, treatment, and long-term outcomes of radiation-induced CNS tumors plays a role in clinical decision-making and patient education. Additionally, as meningiomas and pituitary tumors have been detected at increasing rates across all ages and may potentially be treated with radiation, it is important to know and communicate the risk of secondary tumors in children and adults. After conducting an extensive literature search, we identified publications that report incidence and long-term outcomes of radiation-induced CNS tumors. We reviewed 14 studies in children, which reported that radiation confers a 7- to 10-fold increase in subsequent CNS tumors, with a 20-year cumulative incidence ranging from 1.03 to 28.9 %. The latency period for secondary tumors ranged from 5.5 to 30 years, with gliomas developing in 5-10 years and meningiomas developing around 15 years after radiation. We also reviewed seven studies in adults, where the two strongest studies showed no increased risk while the remaining studies found a higher risk compared to the general population. The latency period for secondary CNS tumors in adults ranged from 5 to 34 years. Treatment and long-term outcomes of radiation-induced CNS tumors have been documented in four case series, which did not conclusively demonstrate that secondary CNS tumors fared worse than primary CNS tumors. Radiation-induced CNS tumors remain a rare occurrence that should not by itself impede radiation treatment. Additional investigation is needed on the risk of radiation-induced tumors in adults and the long-term outcomes of these tumors.

  3. SU-E-T-208: Incidence Cancer Risk From the Radiation Treatment for Acoustic Neuroma Patient

    SciTech Connect

    Kim, D; Chung, W; Shin, D; Yoon, M

    2014-06-01

    Purpose: The present study aimed to compare the incidence risk of a secondary cancer from therapeutic doses in patients receiving intensitymodulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS). Methods: Four acoustic neuroma patients were treated with IMRT, VMAT, or SRS. Their incidnece excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) were estimated using the corresponding therapeutic doses measured at various organs by radio-photoluminescence glass dosimeters (RPLGD) placed inside a humanoid phantom. Results: When a prescription dose was delivered in the planning target volume of the 4 patients, the average organ equivalent doses (OED) at the thyroid, lung, normal liver, colon, bladder, prostate (or ovary), and rectum were measured. The OED decreased as the distance from the primary beam increased. The thyroid received the highest OED compared to other organs. A LAR were estimated that more than 0.03% of AN patients would get radiation-induced cancer. Conclusion: The tyroid was highest radiation-induced cancer risk after radiation treatment for AN. We found that LAR can be increased by the transmitted dose from the primary beam. No modality-specific difference in radiation-induced cancer risk was observed in our study.

  4. Modeling of Radiation Risks for Human Space Missions

    NASA Technical Reports Server (NTRS)

    Fletcher, Graham

    2004-01-01

    Prior to any human space flight, calculations of radiation risks are used to determine the acceptable scope of astronaut activity. Using the supercomputing facilities at NASA Ames Research Center, Ames researchers have determined the damage probabilities of DNA functional groups by space radiation. The data supercede those used in the current Monte Carlo model for risk assessment. One example is the reaction of DNA with hydroxyl radical produced by the interaction of highly energetic particles from space radiation with water molecules in the human body. This reaction is considered an important cause of DNA mutations, although its mechanism is not well understood.

  5. Children’s Exposure to Diagnostic Medical Radiation and Cancer Risk: Epidemiologic and Dosimetric Considerations

    PubMed Central

    Linet, Martha S.; Kim, Kwang pyo; Rajaraman, Preetha

    2009-01-01

    While the etiology of most childhood cancers is largely unknown, epidemiologic studies have consistently found an association between exposure to medical radiation during pregnancy and risk of childhood cancer in offspring. The relation between early life diagnostic radiation exposure and occurrence of pediatric cancer risks is less clear. This review summarizes current and historical estimated doses for common diagnostic radiologic procedures as well as the epidemiologic literature on the role of maternal prenatal, children’s postnatal and parental preconception diagnostic radiologic procedures on subsequent risk of childhood malignancies Risk estimates are presented according to factors such as the year of birth of the child, trimester and medical indication for the procedure, and the number of films taken. The paper also discusses limitations of the methods employed in epidemiologic studies to assess pediatric cancer risks, the effects on clinical practice of the results reported from the epidemiologic studies, and clinical and public health policy implications of the findings. Gaps in understanding and additional research needs are identified. Important research priorities include nationwide surveys to estimate fetal and childhood radiation doses from common diagnostic procedures, and epidemiologic studies to quantify pediatric and lifetime cancer risks from prenatal and early childhood exposures to diagnostic radiography, computed tomography, and fluoroscopically-guided procedures. PMID:19083224

  6. Radiation and cancer risk in atomic-bomb survivors.

    PubMed

    Kodama, K; Ozasa, K; Okubo, T

    2012-03-01

    With the aim of accurately assessing the effects of radiation exposure in the Japanese atomic-bomb survivors, the Radiation Effects Research Foundation has, over several decades, conducted studies of the Life Span Study (LSS) cohort, comprising 93 000 atomic-bomb survivors and 27 000 controls. Solid cancer: the recent report on solid cancer incidence found that at age 70 years following exposure at age 30 years, solid cancer rates increase by about 35%  Gy(-1) for men and 58% Gy(-1) for women. Age-at-exposure is an important risk modifier. In the case of lung cancer, cigarette smoking has been found to be an important risk modifier. Radiation has similar effects on first-primary and second-primary cancer risks. Finally, radiation-associated increases in cancer rates appear to persist throughout life. Leukaemia: the recent report on leukaemia mortality suggests that radiation effects on leukaemia mortality persisted for more than 50 years. Moreover, significant dose-response for myelodysplastic syndrome was observed in Nagasaki LSS members even 40-60 years after radiation exposure. Future perspective: given the continuing solid cancer increase in the survivor population, the LSS will likely continue to provide important new information on radiation exposure and solid cancer risks for another 15-20 years, especially for those exposed at a young age.

  7. Estimation of neutron and other radiation exposure components in low earth orbit

    NASA Technical Reports Server (NTRS)

    Singleterry, R. C. Jr; Badavi, F. F.; Shinn, J. L.; Cucinotta, F. A.; Badhwar, G. D.; Clowdsley, M. S.; Heinbockel, J. H.; Wilson, J. W.; Atwell, W.; Beaujean, R.; Kopp, J.; Reitz, G.

    2001-01-01

    The interaction of high-energy space radiation with spacecraft materials generates a host of secondary particles, some, such as neutrons, are more biologically damaging and penetrating than the original primary particles. Before committing astronauts to long term exposure in such high radiation environments, a quantitative understanding of the exposure and estimates of the associated risks are required. Energetic neutrons are traditionally difficult to measure due to their neutral charge. Measurement methods have been limited by mass and weight requirements in space to nuclear emulsion, activation foils, a limited number of Bonner spheres, and TEPCs. Such measurements have had limited success in quantifying the neutron component relative to the charged components. We will show that a combination of computational models and experimental measurements can be used as a quantitative tool to evaluate the radiation environment within the Shuttle, including neutrons. Comparisons with space measurements are made with special emphasis on neutron sensitive and insensitive devices. c2001 Elsevier Science Ltd. All rights reserved.

  8. Surface daytime net radiation estimation using artificial neural networks

    SciTech Connect

    Jiang, Bo; Zhang, Yi; Liang, Shunlin; Zhang, Xiaotong; Xiao, Zhiqiang

    2014-11-11

    Net all-wave surface radiation (Rn) is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN) models (general regression neural networks (GRNN) and Neuroet) to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991–2010 both in global mode (all data were used to fit the models) and in conditional mode (the data were divided into four subsets and the models were fitted separately). Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R2) of 0.92, a root mean square error (RMSE) of 34.27 W·m–2 , and a bias of –0.61 W·m–2 in global mode based on the validation dataset. In conclusion, ANN methods are a potentially powerful tool for global Rn estimation.

  9. Risky business: challenges and successes in military radiation risk communication.

    PubMed

    Melanson, Mark A; Geckle, Lori S; Davidson, Bethney A

    2012-01-01

    Given the general public's overall lack of knowledge about radiation and their heightened fear of its harmful effects, effective communication of radiation risks is often difficult. This is especially true when it comes to communicating the radiation risks stemming from military operations. Part of this difficulty stems from a lingering distrust of the military that harkens back to the controversy surrounding Veteran exposures to Agent Orange during the Vietnam War along with the often classified nature of many military operations. Additionally, there are unique military exposure scenarios, such as the use of nuclear weapons and combat use of depleted uranium as antiarmor munitions that are not found in the civilian sector. Also, the large, diverse nature of the military makes consistent risk communication across the vast and widespread organization very difficult. This manuscript highlights and discusses both the common and the distinctive challenges of effectively communicating military radiation risks, to include communicating through the media. The paper also introduces the Army's Health Risk Communication Program and its role in assisting in effective risk communication efforts. The authors draw on their extensive collective experience to share 3 risk communication success stories that were accomplished through the innovative use of a matrixed, team approach that combines both health physics and risk communication expertise.

  10. New estimates of the Earth radiation budget under cloud-free conditions and cloud radiative effects

    NASA Astrophysics Data System (ADS)

    Wild, Martin; Hakuba, Maria Z.; Folini, Doris; Schär, Christoph; Long, Charles

    2017-02-01

    In previous studies1, 2 we derived new estimates for the magnitude of the components of the global mean energy budget using to the extent possible the information contained in direct observations from surface and space. Here we establish complementary estimates for the global mean energy budget specifically under cloud-free conditions. The energy fluxes under cloud-free conditions at the Top of Atmosphere (TOA) can be determined with high accuracy from satellite measurements (CERES-EBAF). For the estimation of their counterparts at the Earth's surface we follow the approach presented in our recent studies, based on an analysis of 39 state of the art global climate models from CMIP5 and their bias structure compared to a comprehensive set of high quality surface observations from the Baseline Surface Radiation Network (BSRN). Thereby we infer a best estimate of 249 Wm-2 for the global mean clear-sky downward shortwave radiation at the surface, and a corresponding clear-sky surface shortwave absorption of 216 Wm-2, considering a global mean surface albedo of 13 %. Combined with a best estimate for the global mean net shortwave influx at the TOA under cloud-free skies from CERES-EBAF of 287 Wm-2, this leaves an amount of 71 Wm-2 absorbed shortwave radiation in the cloud-free atmosphere. The 71 Wm-2 coincide with our earlier estimate for this quantity in Wild et al. (2006)3 based on older models and fewer direct observations, suggesting that this estimate is fairly robust. For the clear-sky downward longwave radiation at the Earth surface we obtain a best estimate of 314 Wm-2. A comparison of the clear-sky global energy balance diagram presented here with the corresponding all-sky diagram established in our previous studies enables a quantification of the global mean shortwave, longwave and net cloud-radiative effects at the TOA, within the atmosphere and at the surface, as well as an assessment of their representation in climate models.

  11. Spectral estimates of net radiation and soil heat flux

    USGS Publications Warehouse

    Daughtry, C.S.T.; Kustas, W.P.; Moran, M.S.; Pinter, P. J.; Jackson, R. D.; Brown, P.W.; Nichols, W.D.; Gay, L.W.

    1990-01-01

    Conventional methods of measuring surface energy balance are point measurements and represent only a small area. Remote sensing offers a potential means of measuring outgoing fluxes over large areas at the spatial resolution of the sensor. The objective of this study was to estimate net radiation (Rn) and soil heat flux (G) using remotely sensed multispectral data acquired from an aircraft over large agricultural fields. Ground-based instruments measured Rn and G at nine locations along the flight lines. Incoming fluxes were also measured by ground-based instruments. Outgoing fluxes were estimated using remotely sensed data. Remote Rn, estimated as the algebraic sum of incoming and outgoing fluxes, slightly underestimated Rn measured by the ground-based net radiometers. The mean absolute errors for remote Rn minus measured Rn were less than 7%. Remote G, estimated as a function of a spectral vegetation index and remote Rn, slightly overestimated measured G; however, the mean absolute error for remote G was 13%. Some of the differences between measured and remote values of Rn and G are associated with differences in instrument designs and measurement techniques. The root mean square error for available energy (Rn - G) was 12%. Thus, methods using both ground-based and remotely sensed data can provide reliable estimates of the available energy which can be partitioned into sensible and latent heat under nonadvective conditions. ?? 1990.

  12. Estimates of the radiation environment for a nuclear rocket engine

    SciTech Connect

    Courtney, J.C.; Manohara, H.M.; Williams, M.L.

    1992-12-31

    Ambitious missions in deep space, such as manned expeditions to Mars, require nuclear propulsion if they are to be accomplished in a reasonable length of time. Current technology is adequate to support the use of nuclear fission as a source of energy for propulsion; however, problems associated with neutrons and gammas leaking from the rocket engine must be addressed. Before manned or unmanned space flights are attempted, an extensive ground test program on the rocket engine must be completed. This paper compares estimated radiation levels and nuclear heating rates in and around the rocket engine for both a ground test and space environments.

  13. Managing Lunar and Mars Mission Radiation Risks. Part 1; Cancer Risks, Uncertainties, and Shielding Effectiveness

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Ren, Lei

    2005-01-01

    This document addresses calculations of probability distribution functions (PDFs) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPEs). PDFs are used to test the effectiveness of potential radiation shielding approaches. Monte-Carlo techniques are used to propagate uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments. Competing mortality risks and functional correlations in radiation quality factor uncertainties are treated in the calculations. The cancer risk uncertainty is about four-fold for lunar and Mars mission risk projections. For short-stay lunar missins (<180 d), SPEs present the most significant risk, but one effectively mitigated by shielding. For long-duration (>180 d) lunar or Mars missions, GCR risks may exceed radiation risk limits. While shielding materials are marginally effective in reducing GCR cancer risks because of the penetrating nature of GCR and secondary radiation produced in tissue by relativisitc particles, polyethylene or carbon composite shielding cannot be shown to significantly reduce risk compared to aluminum shielding. Therefore, improving our knowledge of space radiobiology to narrow uncertainties that lead to wide PDFs is the best approach to ensure radiation protection goals are met for space exploration.

  14. Optimal Allocation for the Estimation of Attributable Risk,

    DTIC Science & Technology

    control studies . Various optimal strategies are examined using alternative exposure-specific disease rates. Odd Ratio, Relative Risk and Attributable Risk....This paper derives an expression for the optimum sampling allocation under the minimum variance criterion of the estimated attributable risk for case

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

    NASA Astrophysics Data System (ADS)

    Brooks, A.

    The space environment is made up of many different kinds of radiation so that the proper use of biomarkers is essential to estimate radiation risk. This presentation will evaluate differences between biomarkers of dose and risk and demonstrate why they should not be confused following radiation exposures in deep space. Dose is a physical quantity, while risk is a biological quantity. Many examples exist w ereh dose or changes in biomarkers of dose are inappropriately used as predictors of risk. Without information on the biology of the system, the biomarkers of dose provide little help in predicting risk in tissues or radiation exposure types where no excess risk can be demonstrated. Many of these biomarkers of dose only reflect changes in radiation dose or exposure. However, these markers are often incorrectly used to predict risk. For example, exposure of the trachea or of the deep lung to high-LET alpha particles results in similar changes in the biomarker chromosome damage in these two tissues. Such an observation would predict that the risk for cancer induction would be similar in these two tissues. It has been noted , however, that there has never been a tracheal tumor observed in rats that inhaled radon, but with the same exposure, large numbers of tumors were produced in the deep lung. The biology of the different tissues is the major determinant of the risk rather than the radiation dose. Recognition of this fact has resulted in the generation of tissue weighting factors for use in radiation protection. When tissue weighting factors are used the values derived are still called "dose". It is important to recognize that tissue specific observations have been corrected to reflect risk, and therefore should no longer be viewed as dose. The relative biological effectiveness (RBE) is also used to estimate radiation risk. The use of biomarkers to derive RBE is a difficult since it involves the use of a biological response to a standard low-LET reference radiation

  16. The Australasian Radiation Protection Society's position statement on risks from low levels of ionizing radiation.

    PubMed

    Higson, Donald

    2007-09-30

    Controversy continues on whether or not ionizing radiation is harmful at low doses, with unresolved scientific uncertainty about effects below a few tens of millisieverts. To settle what regulatory controls should apply in this dose region, an assumption has to be made relating dose to the possibility of harm or benefit. The position of the Australasian Radiation Protection Society on this matter is set out in a statement adopted by the Society in 2005. Its salient features are: --There is insufficient evidence to establish a dose-effect relationship for doses that are less than a few tens of millisieverts in a year. A linear extrapolation from higher dose levels should be assumed only for the purpose of applying regulatory controls.--Estimates of collective dose arising from individual doses that are less than some tens of millisieverts in a year should not be used to predict numbers of fatal cancers. --The risk to an individual of doses significantly less than 100 microsieverts in a year is so small, if it exists at all, that regulatory requirements to control exposure at this level are not warranted.

  17. Prototype Biology-Based Radiation Risk Module Project

    NASA Technical Reports Server (NTRS)

    Terrier, Douglas; Clayton, Ronald G.; Patel, Zarana; Hu, Shaowen; Huff, Janice

    2015-01-01

    Biological effects of space radiation and risk mitigation are strategic knowledge gaps for the Evolvable Mars Campaign. The current epidemiology-based NASA Space Cancer Risk (NSCR) model contains large uncertainties (HAT #6.5a) due to lack of information on the radiobiology of galactic cosmic rays (GCR) and lack of human data. The use of experimental models that most accurately replicate the response of human tissues is critical for precision in risk projections. Our proposed study will compare DNA damage, histological, and cell kinetic parameters after irradiation in normal 2D human cells versus 3D tissue models, and it will use a multi-scale computational model (CHASTE) to investigate various biological processes that may contribute to carcinogenesis, including radiation-induced cellular signaling pathways. This cross-disciplinary work, with biological validation of an evolvable mathematical computational model, will help reduce uncertainties within NSCR and aid risk mitigation for radiation-induced carcinogenesis.

  18. Integration of a radiation biomarker into modeling of thyroid carcinogenesis and post-Chernobyl risk assessment

    PubMed Central

    Kaiser, Jan Christian; Meckbach, Reinhard; Eidemüller, Markus; Selmansberger, Martin; Unger, Kristian; Shpak, Viktor; Blettner, Maria; Zitzelsberger, Horst; Jacob, Peter

    2016-01-01

    Strong evidence for the statistical association between radiation exposure and disease has been produced for thyroid cancer by epidemiological studies after the Chernobyl accident. However, limitations of the epidemiological approach in order to explore health risks especially at low doses of radiation appear obvious. Statistical fluctuations due to small case numbers dominate the uncertainty of risk estimates. Molecular radiation markers have been searched extensively to separate radiation-induced cancer cases from sporadic cases. The overexpression of the CLIP2 gene is the most promising of these markers. It was found in the majority of papillary thyroid cancers (PTCs) from young patients included in the Chernobyl tissue bank. Motivated by the CLIP2 findings we propose a mechanistic model which describes PTC development as a sequence of rate-limiting events in two distinct paths of CLIP2-associated and multistage carcinogenesis. It integrates molecular measurements of the dichotomous CLIP2 marker from 141 patients into the epidemiological risk analysis for about 13 000 subjects from the Ukrainian-American cohort which were exposed below age 19 years and were put under enhanced medical surveillance since 1998. For the first time, a radiation risk has been estimated solely from marker measurements. Cross checking with epidemiological estimates and model validation suggests that CLIP2 is a marker of high precision. CLIP2 leaves an imprint in the epidemiological incidence data which is typical for a driver gene. With the mechanistic model, we explore the impact of radiation on the molecular landscape of PTC. The model constitutes a unique interface between molecular biology and radiation epidemiology. PMID:27729373

  19. Assessment of uncertainties in radiation-induced cancer risk predictions at clinically relevant doses

    SciTech Connect

    Nguyen, J.; Moteabbed, M.; Paganetti, H.

    2015-01-15

    Purpose: Theoretical dose–response models offer the possibility to assess second cancer induction risks after external beam therapy. The parameters used in these models are determined with limited data from epidemiological studies. Risk estimations are thus associated with considerable uncertainties. This study aims at illustrating uncertainties when predicting the risk for organ-specific second cancers in the primary radiation field illustrated by choosing selected treatment plans for brain cancer patients. Methods: A widely used risk model was considered in this study. The uncertainties of the model parameters were estimated with reported data of second cancer incidences for various organs. Standard error propagation was then subsequently applied to assess the uncertainty in the risk model. Next, second cancer risks of five pediatric patients treated for cancer in the head and neck regions were calculated. For each case, treatment plans for proton and photon therapy were designed to estimate the uncertainties (a) in the lifetime attributable risk (LAR) for a given treatment modality and (b) when comparing risks of two different treatment modalities. Results: Uncertainties in excess of 100% of the risk were found for almost all organs considered. When applied to treatment plans, the calculated LAR values have uncertainties of the same magnitude. A comparison between cancer risks of different treatment modalities, however, does allow statistically significant conclusions. In the studied cases, the patient averaged LAR ratio of proton and photon treatments was 0.35, 0.56, and 0.59 for brain carcinoma, brain sarcoma, and bone sarcoma, respectively. Their corresponding uncertainties were estimated to be potentially below 5%, depending on uncertainties in dosimetry. Conclusions: The uncertainty in the dose–response curve in cancer risk models makes it currently impractical to predict the risk for an individual external beam treatment. On the other hand, the ratio

  20. Space Radiation Cancer Risks and Uncertainities for Different Mission Time Periods

    NASA Technical Reports Server (NTRS)

    Kim,Myung-Hee Y.; Cucinotta, Francis A.

    2012-01-01

    Space radiation consists of solar particle events (SPEs), comprised largely of medium energy protons (less than several hundred MeV); and galactic cosmic ray (GCR), which includes high energy protons and high charge and energy (HZE) nuclei. For long duration missions, space radiation presents significant health risks including cancer mortality. Probabilistic risk assessment (PRA) is essential for radiation protection of crews on long term space missions outside of the protection of the Earth s magnetic field and for optimization of mission planning and costs. For the assessment of organ dosimetric quantities and cancer risks, the particle spectra at each critical body organs must be characterized. In implementing a PRA approach, a statistical model of SPE fluence was developed, because the individual SPE occurrences themselves are random in nature while the frequency distribution of SPEs depends strongly upon the phase within the solar activity cycle. Spectral variability of SPEs was also examined, because the detailed energy spectra of protons are important especially at high energy levels for assessing the cancer risk associated with energetic particles for large events. An overall cumulative probability of a GCR environment for a specified mission period was estimated for the temporal characterization of the GCR environment represented by the deceleration potential (theta). Finally, this probabilistic approach to space radiation cancer risk was coupled with a model of the radiobiological factors and uncertainties in projecting cancer risks. Probabilities of fatal cancer risk and 95% confidence intervals will be reported for various periods of space missions.

  1. Ionising radiation and risk of death from leukaemia and lymphoma in radiation-monitored workers (INWORKS): an international cohort study

    PubMed Central

    Leuraud, Klervi; Richardson, David B; Cardis, Elisabeth; Daniels, Robert D; Gillies, Michael; O'Hagan, Jacqueline A; Hamra, Ghassan B; Haylock, Richard; Laurier, Dominique; Moissonnier, Monika; Schubauer-Berigan, Mary K; Thierry-Chef, Isabelle; Kesminiene, Ausrele

    2015-01-01

    Summary Background There is much uncertainty about the risks of leukaemia and lymphoma after repeated or protracted low-dose radiation exposure typical of occupational, environmental, and diagnostic medical settings. We quantified associations between protracted low-dose radiation exposures and leukaemia, lymphoma, and multiple myeloma mortality among radiation-monitored adults employed in France, the UK, and the USA. Methods We assembled a cohort of 308 297 radiation-monitored workers employed for at least 1 year by the Atomic Energy Commission, AREVA Nuclear Cycle, or the National Electricity Company in France, the Departments of Energy and Defence in the USA, and nuclear industry employers included in the National Registry for Radiation Workers in the UK. The cohort was followed up for a total of 8·22 million person-years. We ascertained deaths caused by leukaemia, lymphoma, and multiple myeloma. We used Poisson regression to quantify associations between estimated red bone marrow absorbed dose and leukaemia and lymphoma mortality. Findings Doses were accrued at very low rates (mean 1·1 mGy per year, SD 2·6). The excess relative risk of leukaemia mortality (excluding chronic lymphocytic leukaemia) was 2·96 per Gy (90% CI 1·17–5·21; lagged 2 years), most notably because of an association between radiation dose and mortality from chronic myeloid leukaemia (excess relative risk per Gy 10·45, 90% CI 4·48–19·65). Interpretation This study provides strong evidence of positive associations between protracted low-dose radiation exposure and leukaemia. Funding Centers for Disease Control and Prevention, Ministry of Health, Labour and Welfare of Japan, Institut de Radioprotection et de Sûreté Nucléaire, AREVA, Electricité de France, National Institute for Occupational Safety and Health, US Department of Energy, US Department of Health and Human Services, University of North Carolina, Public Health England. PMID:26436129

  2. Radiation effects on cancer risks in the Life Span Study cohort.

    PubMed

    Kodama, Kazunori; Ozasa, Kotaro; Katayama, Hiroaki; Shore, Roy E; Okubo, Toshiteru

    2012-10-01

    To determine late health effects of radiation in atomic bomb survivors, the Radiation Effects Research Foundation has been conducting studies on the Life Span Study (LSS) population, which consists of 93,000 atomic bomb survivors and 27,000 controls. A recent report on the incidence of solid cancers estimates that at the age of 70 y, after exposure at the age of 30 y, solid-cancer rates increase by about 35% per Gy for men and 58% per Gy for women. The age-at-exposure is an important risk modifier. Furthermore, it seems that radiation-associated increases in cancer rates persist throughout life. In addition, radiation has similar effects upon first-primary and second-primary cancer risks. A recent report on leukemia mortality suggested that the effect of radiation on leukemia mortality persisted for more than five decades. In addition, a significant dose-response for myelodysplastic syndrome is found in Nagasaki LSS members 40-60 y after radiation exposure. In view of the nature of the continuing increase in solid cancers, the LSS should continue to provide important new information on cancer risks, as most survivors still alive today were exposed to the atomic bomb radiation under the age of 20 y and are now entering their cancer-prone years.

  3. [Estimation of absolute risk for fracture].

    PubMed

    Fujiwara, Saeko

    2009-03-01

    Osteoporosis treatment aims to prevent fractures and maintain the QOL of the elderly. However, persons at high risk of future fracture cannot be effectively identified on the basis of bone density (BMD) alone, although BMD is used as an diagnostic criterion. Therefore, the WHO recommended that absolute risk for fracture (10-year probability of fracture) for each individual be evaluated and used as an index for intervention threshold. The 10-year probability of fracture is calculated based on age, sex, BMD at the femoral neck (body mass index if BMD is not available), history of previous fractures, parental hip fracture history, smoking, steroid use, rheumatoid arthritis, secondary osteoporosis and alcohol consumption. The WHO has just announced the development of a calculation tool (FRAX: WHO Fracture Risk Assessment Tool) in February this year. Fractures could be prevented more effectively if, based on each country's medical circumstances, an absolute risk value for fracture to determine when to start medical treatment is established and persons at high risk of fracture are identified and treated accordingly.

  4. Recent Updates to Radiation Organ Dose Estimation Tool PIMAL

    SciTech Connect

    Akkurt, Hatice; Wiarda, Dorothea; Eckerman, Keith F

    2011-01-01

    A computational phantom with moving arms and legs and an accompanying graphical user interface, PIMAL, was previously developed to enable radiation dose estimation for different postures in a user-friendly manner. This initial version of the software was useful in adjusting the posture, generating the corresponding MCNP input file, and performing the radiation transport simulations for dose calculations using MCNP5 or MCNPX. However, it only included one mathematical phantom model (hermaphrodite) and allowed only isotropic point sources. Recently, the software was enhanced by adding two more mathematical phantom models, a male and female, and the source features were enhanced significantly by adding internal and external source options in a pull-down menu. Although the initial version of the software included only a mathematical hermaphrodite phantom, the features and models in the software are constantly being enhanced by adding more phantoms as well as other options to enable dose assessment for different configurations/cases in a user-friendly manner. In this latest version of the software, ICRP's recently released reference male and female voxel phantoms are included in a pull-down menu. The male and female models are described using 7 and 14 million voxels, respectively. Currently, the software is being modified further to include the International Commission on Radiation Protection's (ICRP) reference male and female voxel phantoms. Additionally, some case studies are being implemented and included in a library of input files. This paper describes recent updates to the software.

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

    PubMed

    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.

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

    PubMed Central

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

    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 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

  7. Evidence Report: Risk of Acute and Late Central Nervous System Effects from Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Nelson, Gregory A.; Simonsen, Lisa; Huff, Janice L.

    2016-01-01

    Possible acute and late risks to the central nervous system (CNS) from galactic cosmic rays (GCR) and solar particle events (SPE) are concerns for human exploration of space. Acute CNS risks may include: altered cognitive function, reduced motor function, and behavioral changes, all of which may affect performance and human health. Late CNS risks may include neurological disorders such as Alzheimer's disease (AD), dementia and premature aging. Although detrimental CNS changes are observed in humans treated with high-dose radiation (e.g., gamma rays and 9 protons) for cancer and are supported by experimental evidence showing neurocognitive and behavioral effects in animal models, the significance of these results on the morbidity to astronauts has not been elucidated. There is a lack of human epidemiology data on which to base CNS risk estimates; therefore, risk projection based on scaling to human data, as done for cancer risk, is not possible for CNS risks. Research specific to the spaceflight environment using animal and cell models must be compiled to quantify the magnitude of CNS changes in order to estimate this risk and to establish validity of the current permissible exposure limits (PELs). In addition, the impact of radiation exposure in combination with individual sensitivity or other space flight factors, as well as assessment of the need for biological/pharmaceutical countermeasures, will be considered after further definition of CNS risk occurs.

  8. Radiation Dose to the Brain and Subsequent Risk of Developing Brain Tumors in Pediatric Patients Undergoing Interventional Neuroradiology Procedures

    PubMed Central

    Thierry-Chef; Simon, S. L.; Land, C. E.; Miller, D. L.

    2014-01-01

    Radiation dose to the brain and subsequent lifetime risk of diagnosis of radiation-related brain tumors were estimated for pediatric patients undergoing intracranial embolization. Average dose to the whole brain was calculated using dosimetric data from the Radiation Doses in Interventional Radiology Study for 49 pediatric patients who underwent neuroradiological procedures, and lifetime risk of developing radiation-related brain tumors was estimated using published algorithms based on A-bomb survivor data. The distribution of absorbed dose within the brain can vary significantly depending on field size and movement during procedures. Depending on the exposure conditions and age of the patient, organ-averaged brain dose was estimated to vary from 6 to 1600 mGy. The lifetime risk of brain tumor diagnosis was estimated to be increased over the normal background rates (57 cases per 10,000) by 3 to 40% depending on the dose received, age at exposure, and gender. While significant uncertainties are associated with these estimates, we have quantified the range of possible dose and propagated the uncertainty to derive a credible range of estimated lifetime risk for each subject. Collimation and limiting fluoroscopy time and dose rate are the most effective means to minimize dose and risk of future induction of radiation-related tumors. PMID:18959462

  9. Spectral estimators of absorbed photosynthetically active radiation in corn canopies

    NASA Technical Reports Server (NTRS)

    Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

    1985-01-01

    Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a Landsat MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95 percent of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50 percent of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73 percent of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

  10. Spectral estimators of absorbed photosynthetically active radiation in corn canopies

    NASA Technical Reports Server (NTRS)

    Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

    1984-01-01

    Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a LANDSAT MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95% of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50% of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73% of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

  11. Non-parametric estimation of spatial variation in relative risk.

    PubMed

    Kelsall, J E; Diggle, P J

    We consider the problem of estimating the spatial variation in relative risks of two diseases, say, over a geographical region. Using an underlying Poisson point process model, we approach the problem as one of density ratio estimation implemented with a non-parametric kernel smoothing method. In order to assess the significance of any local peaks or troughs in the estimated risk surface, we introduce pointwise tolerance contours which can enhance a greyscale image plot of the estimate. We also propose a Monte Carlo test of the null hypothesis of constant risk over the whole region, to avoid possible over-interpretation of the estimated risk surface. We illustrate the capabilities of the methodology with two epidemiological examples.

  12. Parametric Estimation in a Recurrent Competing Risks Model.

    PubMed

    Taylor, Laura L; Peña, Edsel A

    2013-01-01

    A resource-efficient approach to making inferences about the distributional properties of the failure times in a competing risks setting is presented. Efficiency is gained by observing recurrences of the competing risks over a random monitoring period. The resulting model is called the recurrent competing risks model (RCRM) and is coupled with two repair strategies whenever the system fails. Maximum likelihood estimators of the parameters of the marginal distribution functions associated with each of the competing risks and also of the system lifetime distribution function are presented. Estimators are derived under perfect and partial repair strategies. Consistency and asymptotic properties of the estimators are obtained. The estimation methods are applied to a data set of failures for cars under warranty. Simulation studies are used to ascertain the small sample properties and the efficiency gains of the resulting estimators.

  13. Categorizing sources of risk and the estimated magnitude of risk.

    PubMed

    Aragonés, Juan Ignacio; Moyano, Emilio; Talayero, Fernando

    2008-05-01

    The social perception of risk is considered a multidimensional task, yet little attention has been paid to the cognitive components that organize sources of risk, despite their having been discovered in various research studies. This study attempts to concretely analyze the cultural dimension involved in those processes. In the first phase, we tried to discover to what extent sources of risk are organized into the same categories by people from different countries. In order to do so, two groups of participants were formed: 60 Spanish psychology students and 60 Chilean psychology students classified 43 sources of risk into different groups according to the criteria they found appropriate. The two samples classified risk into identical groups: acts of violence, drugs, electricity and home appliances, household chemicals, chemicals in the environment, public construction projects, transportation, sports, and natural disasters. In a second study, 100 Spanish and 84 Chilean students were asked to evaluate the magnitude of the damage incurred by 17 sources of risk. In both groups, it was observed that the evaluation of damage resulting from each source of risk was affected by its category.

  14. Cardiovascular diseases related to ionizing radiation: The risk of low-dose exposure (Review)

    PubMed Central

    Baselet, Bjorn; Rombouts, Charlotte; Benotmane, Abderrafi Mohammed; Baatout, Sarah; Aerts, An

    2016-01-01

    Traditionally, non-cancer diseases are not considered as health risks following exposure to low doses of ionizing radiation. Indeed, non-cancer diseases are classified as deterministic tissue reactions, which are characterized by a threshold dose. It is judged that below an absorbed dose of 100 mGy, no clinically relevant tissue damage occurs, forming the basis for the current radiation protection system concerning non-cancer effects. Recent epidemiological findings point, however, to an excess risk of non-cancer diseases following exposure to lower doses of ionizing radiation than was previously thought. The evidence is the most sound for cardiovascular disease (CVD) and cataract. Due to limited statistical power, the dose-risk relationship is undetermined below 0.5 Gy; however, if this relationship proves to be without a threshold, it may have considerable impact on current low-dose health risk estimates. In this review, we describe the CVD risk related to low doses of ionizing radiation, the clinical manifestation and the pathology of radiation-induced CVD, as well as the importance of the endothelium models in CVD research as a way forward to complement the epidemiological data with the underlying biological and molecular mechanisms. PMID:27748824

  15. A generic computerized method for estimate of familial risks.

    PubMed Central

    Colombet, Isabelle; Xu, Yigang; Jaulent, Marie-Christine; Desages, Daniel; Degoulet, Patrice; Chatellier, Gilles

    2002-01-01

    Most guidelines developed for cancers screening and for cardiovascular risk management use rules to estimate familial risk. These rules are complex, difficult to memorize, and need to collect a complete pedigree. This paper describes a generic computerized method to estimate familial risks and its implementation in an internet-based application. The program is based on 3 generic models: a model of the family; a model of familial risk; a display model for the pedigree. The model of family allows to represent each member of the family and to construct and display a family tree. The model of familial risk is generic and allows easy update of the program with new diseases or new rules. It was possible to implement guidelines dealing with breast and colorectal cancer and cardiovascular diseases prevention. First evaluation with general practitioners showed that the program was usable. Impact on quality of familial risk estimate should be more documented. PMID:12463810

  16. Time-dependent radiation hazard estimations during space flights

    NASA Astrophysics Data System (ADS)

    Dobynde, Mikhail; Shprits, Yuri; Drozdov, Alexander

    Cosmic particle radiation is a limiting factor for the out of magnetosphere crewed flights. The cosmic radiation uncrewed flights inside heliosphere and crewed flights inside of magnetosphere tend to become a routine procedure, whereas there have been only few shot time flights out of it (Apollo missions 1969-1972) with maximum duration less than a month. Long term crewed missions set much higher requirements to the radiation shielding, primarily because of long exposition term. Inside the helosphere there are two main sources of cosmic radiation: galactic cosmic rays (GCR) and coronal mass ejections (CME). GCR come from the outside of heliosphere forming a background of overall radiation that affects the spacecraft. The intensity of GCR is varied according to solar activity, increasing with solar activity decrease and backward, with the modulation time (time between nearest maxima) of 11 yeas. CME are shot term events, comparing to GCR modulation time, but are much more energetic. The probability of CME increases with the increase of solar activity. Time dependences of the intensity of these two components encourage looking for a time window of flight, when intensity and affection of CME and GCR would be minimized. Applying time dependent models of GCR spectra [1] and estimations of CME we show the time dependence of the radiation dose in a realistic human phantom [2] 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 the incident particle energy, at the same time minimizing flow of secondary induced particles and

  17. Assessment of Methods for Estimating Risk to Birds from ...

    EPA Pesticide Factsheets

    The U.S. EPA Ecological Risk Assessment Support Center (ERASC) announced the release of the final report entitled, Assessment of Methods for Estimating Risk to Birds from Ingestion of Contaminated Grit Particles. This report evaluates approaches for estimating the probability of ingestion by birds of contaminated particles such as pesticide granules or lead particles (i.e. shot or bullet fragments). In addition, it presents an approach for using this information to estimate the risk of mortality to birds from ingestion of lead particles. Response to ERASC Request #16

  18. Radiation and risk: A look at the data

    SciTech Connect

    Schillaci, M.E.

    1996-10-01

    This paper is a review of current data on the risks associated with human exposure to ionizing radiation. We examine these risks for dose levels ranging from very high (atomic bomb survivors) to very low (background). The principal end point considered is cancer mortality. Cancer is the only observed clinical manifestation of radiation-induced stochastic effects. Stochastic effects are caused by subtle radiation-induced cellular changes (DNA mutations) that are random in nature and have no threshold dose (assuming less than perfect repair). The probability of such effects increases with dose, but the severity does not. The time required for cancer to develop ranges from several years for leukemia to decades for solid tumors. In addition to somatic cells, radiation can also damage germ cells (ova and sperm) to produce hereditary effects, which are also classified as stochastic. However, clinical manifestations of such effects have not been observed in humans at a statistically significant level.

  19. Resources for global risk assessment: the International Toxicity Estimates for Risk (ITER) and Risk Information Exchange (RiskIE) databases.

    PubMed

    Wullenweber, Andrea; Kroner, Oliver; Kohrman, Melissa; Maier, Andrew; Dourson, Michael; Rak, Andrew; Wexler, Philip; Tomljanovic, Chuck

    2008-11-15

    The rate of chemical synthesis and use has outpaced the development of risk values and the resolution of risk assessment methodology questions. In addition, available risk values derived by different organizations may vary due to scientific judgments, mission of the organization, or use of more recently published data. Further, each organization derives values for a unique chemical list so it can be challenging to locate data on a given chemical. Two Internet resources are available to address these issues. First, the International Toxicity Estimates for Risk (ITER) database (www.tera.org/iter) provides chronic human health risk assessment data from a variety of organizations worldwide in a side-by-side format, explains differences in risk values derived by different organizations, and links directly to each organization's website for more detailed information. It is also the only database that includes risk information from independent parties whose risk values have undergone independent peer review. Second, the Risk Information Exchange (RiskIE) is a database of in progress chemical risk assessment work, and includes non-chemical information related to human health risk assessment, such as training modules, white papers and risk documents. RiskIE is available at http://www.allianceforrisk.org/RiskIE.htm, and will join ITER on National Library of Medicine's TOXNET (http://toxnet.nlm.nih.gov/). Together, ITER and RiskIE provide risk assessors essential tools for easily identifying and comparing available risk data, for sharing in progress assessments, and for enhancing interaction among risk assessment groups to decrease duplication of effort and to harmonize risk assessment procedures across organizations.

  20. Risk of a second cancer from scattered radiation in acoustic neuroma treatment

    NASA Astrophysics Data System (ADS)

    Yoon, Myonggeun; Lee, Hyunho; Sung, Jiwon; Shin, Dongoh; Park, Sungho; Chung, Weon Kuu; Jahng, Geon-Ho; Kim, Dong Wook

    2014-06-01

    The present study aimed to compare the risk of a secondary cancer from scattered and leakage doses in patients receiving intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS). Four acoustic neuroma patients were treated with IMRT, VMAT, or SRS. Their excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) of a secondary cancer were estimated using the corresponding secondary doses measured at various organs by using radio-photoluminescence glass dosimeters (RPLGD) placed inside a humanoid phantom. When a prescription dose was delivered in the planning target volume of the 4 patients, the average organ equivalent doses (OED) at the thyroid, lung, liver, bowel, bladder, prostate (or ovary), and rectum were 14.6, 1.7, 0.9, 0.8, 0.6, 0.6, and 0.6 cGy, respectively, for IMRT whereas they were 19.1, 1.8, 2.0, 0.6, 0.4, 0.4, and 0.4 cGy, respectively, for VMAT, and 22.8, 4.6, 1.4, 0.7, 0.5, 0.5, and 0.5 cGy, respectively, for SRS. The OED decreased as the distance from the primary beam increased. The thyroid received the highest OED compared to other organs. A lifetime attributable risk evaluation estimated that more than 0.03% of acoustic neuroma (AN) patients would get radiation-induced cancer within 20 years of receiving radiation therapy. The organ with the highest radiation-induced cancer risk after radiation treatment for AN was the thyroid. We found that the LAR could be increased by the transmitted dose from the primary beam. No modality-specific difference in radiation-induced cancer risk was observed in our study.

  1. Estimated ultraviolet radiation doses in wetlands in six national parks

    USGS Publications Warehouse

    Diamond, S.A.; Trenham, P.C.; Adams, Michael J.; Hossack, B.R.; Knapp, R.A.; Stark, L.; Bradford, D.; Corn, P.S.; Czarnowski, K.; Brooks, P.D.; Fagre, D.B.; Breen, B.; Dentenbeck, N.E.; Tonnessen, K.

    2005-01-01

    Ultraviolet-B radiation (UV-B, 280–320-nm wavelengths) doses were estimated for 1024 wetlands in six national parks: Acadia (Acadia), Glacier (Glacier), Great Smoky Mountains (Smoky), Olympic (Olympic), Rocky Mountain (Rocky), and Sequoia/Kings Canyon (Sequoia). Estimates were made using ground-based UV-B data (Brewer spectrophotometers), solar radiation models, GIS tools, field characterization of vegetative features, and quantification of DOC concentration and spectral absorbance. UV-B dose estimates were made for the summer solstice, at a depth of 1 cm in each wetland. The mean dose across all wetlands and parks was 19.3 W-h m−2 (range of 3.4–32.1 W-h m−2). The mean dose was lowest in Acadia (13.7 W-h m−2) and highest in Rocky (24.4 W-h m−2). Doses were significantly different among all parks. These wetland doses correspond to UV-B flux of 125.0 μW cm−2 (range 21.4–194.7 μW cm−2) based on a day length, averaged among all parks, of 15.5 h. Dissolved organic carbon (DOC), a key determinant of water-column UV-B flux, ranged from 0.6 (analytical detection limit) to 36.7 mg C L−1 over all wetlands and parks, and reduced potential maximal UV-B doses at 1-cm depth by 1%–87 %. DOC concentration, as well as its effect on dose, was lowest in Sequoia and highest in Acadia (DOC was equivalent in Acadia, Glacier, and Rocky). Landscape reduction of potential maximal UV-B doses ranged from zero to 77% and was lowest in Sequoia. These regional differences in UV-B wetland dose illustrate the importance of considering all aspects of exposure in evaluating the potential impact of UV-B on aquatic organisms.

  2. Radiation dose estimate in small animal SPECT and PET.

    PubMed

    Funk, Tobias; Sun, Mingshan; Hasegawa, Bruce H

    2004-09-01

    Calculations of radiation dose are important in assessing the medical and biological implications of ionizing radiation in medical imaging techniques such as SPECT and PET. In contrast, radiation dose estimates of SPECT and PET imaging of small animals are not very well established. For that reason we have estimated the whole-body radiation dose to mice and rats for isotopes such as 18F, 99mTc, 201Tl, (111)In, 123I, and 125I that are used commonly for small animal imaging. We have approximated mouse and rat bodies with uniform soft tissue equivalent ellipsoids. The mouse and rat sized ellipsoids had a mass of 30 g and 300 g, respectively, and a ratio of the principal axes of 1:1:4 and 0.7:1:4. The absorbed fractions for various photon energies have been calculated using the Monte Carlo software package MCNP. Using these values, we then calculated MIRD S-values for two geometries that model the distribution of activity in the animal body: (a) a central point source and (b) a homogeneously distributed source, and compared these values against S-value calculations for small ellipsoids tabulated in MIRD Pamphlet 8 to validate our results. Finally we calculated the radiation dose taking into account the biological half-life of the radiopharmaceuticals and the amount of activity administered. Our calculations produced S-values between 1.06 x 10(-13) Gy/Bq s and 2.77 x 10(-13) Gy/Bq s for SPECT agents, and 15.0 x 10(-13) Gy/Bq s for the PET agent 18F, assuming mouse sized ellipsoids with uniform source distribution. The S-values for a central point source in an ellipsoid are about 10% higher than the values obtained for the uniform source distribution. Furthermore, the S-values for mouse sized ellipsoids are approximately 10 times higher than for the rat sized ellipsoids reflecting the difference in mass. We reviewed published data to obtain administered radioactivity and residence times for small animal imaging. From these values and our computed S-values we estimated

  3. Exposure Risks Among Children Undergoing Radiation Therapy: Considerations in the Era of Image Guided Radiation Therapy.

    PubMed

    Hess, Clayton B; Thompson, Holly M; Benedict, Stanley H; Seibert, J Anthony; Wong, Kenneth; Vaughan, Andrew T; Chen, Allen M

    2016-04-01

    Recent improvements in toxicity profiles of pediatric oncology patients are attributable, in part, to advances in the field of radiation oncology such as intensity modulated radiation (IMRT) and proton therapy (IMPT). While IMRT and IMPT deliver highly conformal dose to targeted volumes, they commonly demand the addition of 2- or 3-dimensional imaging for precise positioning--a technique known as image guided radiation therapy (IGRT). In this manuscript we address strategies to further minimize exposure risk in children by reducing effective IGRT dose. Portal X rays and cone beam computed tomography (CBCT) are commonly used to verify patient position during IGRT and, because their relative radiation exposure is far less than the radiation absorbed from therapeutic treatment beams, their sometimes significant contribution to cumulative risk can be easily overlooked. Optimizing the conformality of IMRT/IMPT while simultaneously ignoring IGRT dose may result in organs at risk being exposed to a greater proportion of radiation from IGRT than from therapeutic beams. Over a treatment course, cumulative central-axis CBCT effective dose can approach or supersede the amount of radiation absorbed from a single treatment fraction, a theoretical increase of 3% to 5% in mutagenic risk. In select scenarios, this may result in the underprediction of acute and late toxicity risk (such as azoospermia, ovarian dysfunction, or increased lifetime mutagenic risk) in radiation-sensitive organs and patients. Although dependent on variables such as patient age, gender, weight, body habitus, anatomic location, and dose-toxicity thresholds, modifying IGRT use and acquisition parameters such as frequency, imaging modality, beam energy, current, voltage, rotational degree, collimation, field size, reconstruction algorithm, and documentation can reduce exposure, avoid unnecessary toxicity, and achieve doses as low as reasonably achievable, promoting a culture and practice of "gentle IGRT."

  4. Was the Risk from Nursing-Home Evacuation after the Fukushima Accident Higher than the Radiation Risk?

    PubMed

    Murakami, Michio; Ono, Kyoko; Tsubokura, Masaharu; Nomura, Shuhei; Oikawa, Tomoyoshi; Oka, Tosihiro; Kami, Masahiro; Oki, Taikan

    2015-01-01

    After the 2011 accident at the Fukushima Daiichi nuclear power plant, nursing-home residents and staff were evacuated voluntarily from damaged areas to avoid radiation exposure. Unfortunately, the evacuation resulted in increased mortalities among nursing home residents. We assessed the risk trade-off between evacuation and radiation for 191 residents and 184 staff at three nursing homes by using the same detriment indicator, namely loss of life expectancy (LLE), under four scenarios, i.e. "rapid evacuation (in accordance with the actual situation; i.e. evacuation on 22 March)," "deliberate evacuation (i.e. evacuation on 20 June)," "20-mSv exposure," and "100-mSv exposure." The LLE from evacuation-related mortality among nursing home residents was assessed with survival probability data from nursing homes in the city of Minamisoma and the city of Soma. The LLE from radiation mortality was calculated from the estimated age-specific mortality rates from leukemia and all solid cancers based on the additional effective doses and the survival probabilities. The total LLE of residents due to evacuation-related risks in rapid evacuation was 11,000 persons-d-much higher than the total LLEs of residents and staff due to radiation in the other scenarios (27, 1100, and 5800 persons-d for deliberate evacuation, 20 mSv-exposure, and 100 mSv-exposure, respectively). The latitude for reducing evacuation risks among nursing home residents is surprisingly large. Evacuation regulation and planning should therefore be well balanced with the trade-offs against radiation risks. This is the first quantitative assessment of the risk trade-off between radiation exposure and evacuation after a nuclear power plant accident.

  5. Was the Risk from Nursing-Home Evacuation after the Fukushima Accident Higher than the Radiation Risk?

    PubMed Central

    Murakami, Michio; Ono, Kyoko; Tsubokura, Masaharu; Nomura, Shuhei; Oikawa, Tomoyoshi; Oka, Tosihiro; Kami, Masahiro; Oki, Taikan

    2015-01-01

    After the 2011 accident at the Fukushima Daiichi nuclear power plant, nursing-home residents and staff were evacuated voluntarily from damaged areas to avoid radiation exposure. Unfortunately, the evacuation resulted in increased mortalities among nursing home residents. We assessed the risk trade-off between evacuation and radiation for 191 residents and 184 staff at three nursing homes by using the same detriment indicator, namely loss of life expectancy (LLE), under four scenarios, i.e. “rapid evacuation (in accordance with the actual situation; i.e. evacuation on 22 March),” “deliberate evacuation (i.e. evacuation on 20 June),” “20-mSv exposure,” and “100-mSv exposure.” The LLE from evacuation-related mortality among nursing home residents was assessed with survival probability data from nursing homes in the city of Minamisoma and the city of Soma. The LLE from radiation mortality was calculated from the estimated age-specific mortality rates from leukemia and all solid cancers based on the additional effective doses and the survival probabilities. The total LLE of residents due to evacuation-related risks in rapid evacuation was 11,000 persons-d—much higher than the total LLEs of residents and staff due to radiation in the other scenarios (27, 1100, and 5800 persons-d for deliberate evacuation, 20 mSv-exposure, and 100 mSv-exposure, respectively). The latitude for reducing evacuation risks among nursing home residents is surprisingly large. Evacuation regulation and planning should therefore be well balanced with the trade-offs against radiation risks. This is the first quantitative assessment of the risk trade-off between radiation exposure and evacuation after a nuclear power plant accident. PMID:26359666

  6. Evidence Report: Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Patel, Zarana; Huff, Janice; Saha, Janapriya; Wang, Minli; Blattnig, Steve; Wu, Honglu; Cucinotta, Francis

    2015-01-01

    (SI unit for ionizing radiation dosage, i.e. one joule of radiation energy per one kilogram of matter)) to facilitate risk prediction. This risk has considerable uncertainty associated with it, and no acceptable model for projecting degenerative tissue risk is currently available. In particular, risk factors such as obesity, alcohol, and tobacco use can act as confounding factors that contribute to the large uncertainties. The PELs could be violated under certain scenarios, including following a large SPE (solar proton event) or long-term GCR (galactic cosmic ray) exposure. Specifically, for a Mars mission, the accumulated dose is sufficiently high that epidemiology data and preliminary risk estimates suggest a significant risk for cardiovascular disease. Ongoing research in this area is intended to provide the evidence base for accurate risk quantification to determine criticality for extended duration missions. Data specific to the space radiation environment must be compiled to quantify the magnitude of this risk to decrease the uncertainty in current PELs and to determine if additional protection strategies are required. New research results could lead to estimates of cumulative radiation risk from CNS and degenerative tissue diseases that, when combined with the cancer risk, may have major negative impacts on mission design, costs, schedule, and crew selection. The current report amends an earlier report (Human Research Program Requirements Document, HRP-47052, Rev. C, dated Jan 2009) in order to provide an update of evidence since 2009.

  7. Transport calculations and accelerator experiments needed for radiation risk assessment in space.

    PubMed

    Sihver, Lembit

    2008-01-01

    The major uncertainties on space radiation risk estimates in humans are associated to the poor knowledge of the biological effects of low and high LET radiation, with a smaller contribution coming from the characterization of space radiation field and its primary interactions with the shielding and the human body. However, to decrease the uncertainties on the biological effects and increase the accuracy of the risk coefficients for charged particles radiation, the initial charged-particle spectra from the Galactic Cosmic Rays (GCRs) and the Solar Particle Events (SPEs), and the radiation transport through the shielding material of the space vehicle and the human body, must be better estimated Since it is practically impossible to measure all primary and secondary particles from all possible position-projectile-target-energy combinations needed for a correct risk assessment in space, accurate particle and heavy ion transport codes must be used. These codes are also needed when estimating the risk for radiation induced failures in advanced microelectronics, such as single-event effects, etc., and the efficiency of different shielding materials. It is therefore important that the models and transport codes will be carefully benchmarked and validated to make sure they fulfill preset accuracy criteria, e.g. to be able to predict particle fluence, dose and energy distributions within a certain accuracy. When validating the accuracy of the transport codes, both space and ground based accelerator experiments are needed The efficiency of passive shielding and protection of electronic devices should also be tested in accelerator experiments and compared to simulations using different transport codes. In this paper different multipurpose particle and heavy ion transport codes will be presented, different concepts of shielding and protection discussed, as well as future accelerator experiments needed for testing and validating codes and shielding materials.

  8. Radiation in the workplace-a review of studies of the risks of occupational exposure to ionising radiation.

    PubMed

    Wakeford, Richard

    2009-06-01

    Many individuals are, or have been, exposed to ionising radiation in the course of their work and the epidemiological study of occupationally irradiated groups offers an important opportunity to complement the estimates of risks to health resulting from exposure to radiation that are obtained from other populations, such as the Japanese survivors of the atomic bombings of Hiroshima and Nagasaki in 1945. Moreover, workplace exposure to radiation usually involves irradiation conditions that are of direct relevance to the principal concern of radiological protection: protracted exposure to low level radiation. Further, some workers have been exposed to radioactive material that has been inadvertently taken into the body, and the study of these groups leads to risk estimates derived directly from the experience of those irradiated by these 'internal emitters', intakes of alpha-particle-emitters being of particular interest. Workforces that have been the subject of epidemiological study include medical staff, aircrews, radium dial luminisers, underground hard-rock miners, Chernobyl clean-up workers, nuclear weapons test participants and nuclear industry workers. The first solid epidemiological evidence of the stochastic effects of irradiation came from a study of occupational exposure to medical x-rays that was reported in 1944, which demonstrated a large excess risk of leukaemia among US radiologists; but the general lack of dose records for early medical staff who tended to experience the highest exposures hampers the derivation of risks per unit dose received by medical workers. The instrument dial luminisers who inadvertently ingested large amounts of radium-based paint and underground hard-rock miners who inhaled large quantities of radon and its decay products suffered markedly raised excess risks of, respectively, bone and lung cancers; the miner studies have provided standard risk estimates for radon-induced lung cancer. The large numbers of nuclear industry

  9. Electromagnetic radiation--parameters for risk assessment.

    PubMed

    Israel, M S

    1994-01-01

    The assessment of human exposure to electromagnetic radiation (EMR) under occupational and environmental conditions is one of the most complicated problems of public health science and practice. The problems arise from the very essence of EMR, the conflicting requirements of the measuring instruments, the complexity of electromagnetic waves in the working environment, and the still unknown mechanisms of their biological effects. One of the best ways to develop methods and criteria for exposure assessment of EMR is to determine the electromagnetic field parameters as well as those related to the quantity of energy absorbed by the organism. Definitions have been given mainly regarding tissues' electric and magnetic characteristics, and regarding the energetic parameters of EMR, without description of concrete methods of exposure assessment in different complicated cases of wide-ranging impulsive, non-homogeneous radiation. The best parameters for exposure assessment are the Specific Absorption Rate (SAR), the energetic loading of the human body (the electromagnetic dose W), the time-weighted average (TWA), using time-dependent hygienic norms and standards.

  10. Development of human epithelial cell systems for radiation risk assessment

    NASA Astrophysics Data System (ADS)

    Yang, C. H.; Craise, L. M.

    1994-10-01

    The most important health effect of space radiation for astronauts is cancer induction. For radiation risk assessment, an understanding of carcinogenic effect of heavy ions in human cells is most essential. In our laboratory, we have successfully developed a human mammary epithelial cell system for studying the neoplastic transformation in vitro. Growth variants were obtained from heavy ion irradiated immortal mammary cell line. These cloned growth variants can grow in regular tissue culture media and maintain anchorage dependent growth and density inhibition property. Upon further irradiation with high-LET radiation, transformed foci were found. Experimental results from these studies suggest that multiexposure of radiation is required to induce neoplastic transformation of human epithelial cells. This multihits requirement may be due to high genomic stability of human cells. These growth variants can be useful model systems for space flight experiments to determine the carcinogenic effect of space radiation in human epithelial cells.

  11. Development of human epithelial cell systems for radiation risk assessment

    NASA Technical Reports Server (NTRS)

    Yang, C. H.; Craise, L. M.

    1994-01-01

    The most important health effect of space radiation for astronauts is cancer induction. For radiation risk assessment, an understanding of carcinogenic effect of heavy ions in human cells is most essential. In our laboratory, we have successfully developed a human mammary epithelial cell system for studying the neoplastic transformation in vitro. Growth variants were obtained from heavy ion irradiated immortal mammary cell line. These cloned growth variants can grow in regular tissue culture media and maintain anchorage dependent growth and density inhibition property. Upon further irradiation with high-Linear Energy Transfer (LET) radiation, transformed foci were found. Experimental results from these studies suggest that multiexposure of radiation is required to induce neoplastic tranformation of human epithelial cells. This multihits requirement may be due to high genomic stability of human cells. These growth variants can be useful model systems for space flight experiments to determine the carcinogenic effect of space radiation in human epithelial cells.

  12. The Concentration Of Tritium In Urine And Internal Radiation Dose Estimation Of PTNBR Radiation Workers

    SciTech Connect

    Tjahaja, Poppy Intan; Sukmabuana, Putu; Aisyah, Neneng Nur

    2010-12-23

    The operation of Triga 2000 reactor in Nuclear Technology Center for Materials and Radiometry (PTNBR BATAN) normally produce tritium radionuclide which is the activation product of deuterium atom in reactor primary cooling water. According to previous monitoring, tritium was detected with the concentration of 8.236{+-}0.677 kBq/L and 1.704{+-}0.046 Bq/L in the primary cooling water and in reactor hall air, respectively. The tritium in reactor hall air chronically can be inhaled by the workers. In this research, tritium content in radiation workers' urine was determined to estimate the internal radiation doses received by the workers. About 50-100 mL of urine samples were collected from 48 PTNBR workers that is classified as 24 radiation workers and 24 administration staffs as a control. Urine samples of 25 mL were then prepared by active charcoal and KMnO{sub 4} addition and followed with complete distillation. The 2 mL of distillate was added with 13 mL scintillator, shaked vigorously and remained in cool and dark condition for about 24 hours. The tritium in the samples was then measured using liquid scintillation counter (LSC) for 1 hour. From the measurement results it was obtained that the tritium concentration in the urine of radiation workers were in the range of not detected and 5.191 Bq/mL, whereas in the administration staffs the concentration were between not detected and 4.607 Bq/mL. Internally radiation doses were calculated using the tritium concentration data, and it was found the averages about 0.602 {mu}Sv/year and 0.532 {mu}Sv/year for radiation workers and administration staffs, respectively. The doses received by the workers were lower than that of the permissible doses from tritium, i.e. 40 {mu}Sv/year.

  13. Risk of Radiation Retinopathy in Patients With Orbital and Ocular Lymphoma

    SciTech Connect

    Kaushik, Megha; Pulido, Jose S.; Schild, Steven E.; Stafford, Scott

    2012-12-01

    Purpose: Radiation retinopathy is a potential long-term complication of radiation therapy to the orbit. The risk of developing this adverse effect is dose dependent; however, the threshold is unclear. The aim of this study was to identify the risk of developing radiation retinopathy at increasing radiation doses. Methods and Materials: A 40-year retrospective review was performed of patients who received external beam radiation therapy for ocular/orbital non-Hodgkin lymphoma (NHL). Results: Sixty-seven patients who had at least one ophthalmic follow-up examination were included in this study. Most patients (52%) were diagnosed with NHL involving the orbit. Patients received external beam radiation therapy at doses between 1886 and 5400 cGy (mean, 3033 {+-} 782 cGy). Radiation retinopathy developed in 12% of patients, and the median time to diagnosis was 27 months (range, 15-241months). The mean prescribed radiation dose in patients with retinopathy was 3309 {+-} 585 cGy, and the estimated retinal dose (derived by reviewing the dosimetry) was 3087 {+-} 1030 cGy. The incidence of retinopathy increased with dose. The average prescribed daily fractionated dose was higher in patients who developed retinopathy than in patients who did not (mean, 202 cGy vs 180 cGy, respectively; P = .04). More patients with radiation retinopathy had comorbid diabetes mellitus type 2 than patients without retinopathy (P = .015). In our study, the mean visual acuity of the eyes that received radiation was worse than that of the eyes that did not (P = .027). Other postradiotherapy ocular findings included keratitis (6%), dry eyes (39%), and cataract (33%). Conclusions: Radiation retinopathy, a known complication of radiotherapy for orbital tumors, relates to vascular comorbidities and dose. Higher total doses and larger daily fractions (>180 cGy) appear to be related to higher rates of retinopathy. Future larger studies are required to identify a statistically significant threshold for the

  14. Getting ready for the manned mission to Mars: the astronauts' risk from space radiation.

    PubMed

    Hellweg, Christine E; Baumstark-Khan, Christa

    2007-07-01

    Space programmes are shifting towards planetary exploration and, in particular, towards missions by human beings to the Moon and to Mars. Radiation is considered to be one of the major hazards for personnel in space and has emerged as the most critical issue to be resolved for long-term missions both orbital and interplanetary. The two cosmic sources of radiation that could impact a mission outside the Earth's magnetic field are solar particle events (SPE) and galactic cosmic rays (GCR). Exposure to the types of ionizing radiation encountered during space travel may cause a number of health-related problems, but the primary concern is related to the increased risk of cancer induction in astronauts. Predictions of cancer risk and acceptable radiation exposure in space are extrapolated from minimal data and are subject to many uncertainties. The paper describes present-day estimates of equivalent doses from GCR and solar cosmic radiation behind various shields and radiation risks for astronauts on a mission to Mars.

  15. Getting ready for the manned mission to Mars: the astronauts' risk from space radiation

    NASA Astrophysics Data System (ADS)

    Hellweg, Christine E.; Baumstark-Khan, Christa

    2007-07-01

    Space programmes are shifting towards planetary exploration and, in particular, towards missions by human beings to the Moon and to Mars. Radiation is considered to be one of the major hazards for personnel in space and has emerged as the most critical issue to be resolved for long-term missions both orbital and interplanetary. The two cosmic sources of radiation that could impact a mission outside the Earth’s magnetic field are solar particle events (SPE) and galactic cosmic rays (GCR). Exposure to the types of ionizing radiation encountered during space travel may cause a number of health-related problems, but the primary concern is related to the increased risk of cancer induction in astronauts. Predictions of cancer risk and acceptable radiation exposure in space are extrapolated from minimal data and are subject to many uncertainties. The paper describes present-day estimates of equivalent doses from GCR and solar cosmic radiation behind various shields and radiation risks for astronauts on a mission to Mars.

  16. Thinking Concretely Increases the Perceived Likelihood of Risks: The Effect of Construal Level on Risk Estimation.

    PubMed

    Lermer, Eva; Streicher, Bernhard; Sachs, Rainer; Raue, Martina; Frey, Dieter

    2016-03-01

    Recent findings on construal level theory (CLT) suggest that abstract thinking leads to a lower estimated probability of an event occurring compared to concrete thinking. We applied this idea to the risk context and explored the influence of construal level (CL) on the overestimation of small and underestimation of large probabilities for risk estimates concerning a vague target person (Study 1 and Study 3) and personal risk estimates (Study 2). We were specifically interested in whether the often-found overestimation of small probabilities could be reduced with abstract thinking, and the often-found underestimation of large probabilities was reduced with concrete thinking. The results showed that CL influenced risk estimates. In particular, a concrete mindset led to higher risk estimates compared to an abstract mindset for several adverse events, including events with small and large probabilities. This suggests that CL manipulation can indeed be used for improving the accuracy of lay people's estimates of small and large probabilities. Moreover, the results suggest that professional risk managers' risk estimates of common events (thus with a relatively high probability) could be improved by adopting a concrete mindset. However, the abstract manipulation did not lead managers to estimate extremely unlikely events more accurately. Potential reasons for different CL manipulation effects on risk estimates' accuracy between lay people and risk managers are discussed.

  17. Evaluation of risk from space radiation with high-energy heavy ion beams

    NASA Technical Reports Server (NTRS)

    Schimmerling, W.; Wilson, J. W.; Cucinotta, F.; Kim, M. H.

    1998-01-01

    The most challenging radiation in space consists of fully ionized atomic elements with high energy for which only the few lowest energy ions can be stopped in shielding materials. The health risk from exposure to these ions and their secondary radiations generated in shield materials is poorly understood since there are few human data and a systematic study in relevant animal model systems has not been made. The accuracy of risk prediction is described as the major limiting factor in the management of space radiation risk. The expected impact of systematic studies is examined using the limited available biological data and models. Given the limitations of current predictions, models must be developed that are able to incorporate the required fundamental scientific data into accurate risk estimates. The important radiation components that can be provided for laboratory testing are identified. The use of ground-based accelerator beams to simulate space radiation is explained and quantitative scientific constraints on such facilities are derived. Three facilities, one each in the United States, in Germany and in Japan, currently have the partial capability to satisfy these constraints. A facility has been proposed using the Brookhaven National Laboratory Booster Synchrotron in the United States; in conjuction with other on-site accelerators, it will be able to provide the full range of heavy ion beams and energies required.

  18. Technical Evaluation of the NASA Model for Cancer Risk to Astronauts Due to Space Radiation

    NASA Technical Reports Server (NTRS)

    2012-01-01

    At the request of NASA, the National Research Council's (NRC's) Committee for Evaluation of Space Radiation Cancer Risk Model reviewed a number of changes that NASA proposes to make to its model for estimating the risk of radiation-induced cancer in astronauts. The NASA model in current use was last updated in 2005, and the proposed model would incorporate recent research directed at improving the quantification and understanding of the health risks posed by the space radiation environment. NASA's proposed model is defined by the 2011 NASA report Space Radiation Cancer Risk Projections and Uncertainties 2010 (Cucinotta et al., 2011). The committee's evaluation is based primarily on this source, which is referred to hereafter as the 2011 NASA report, with mention of specific sections or tables cited more formally as Cucinotta et al. (2011). The overall process for estimating cancer risks due to low linear energy transfer (LET) radiation exposure has been fully described in reports by a number of organizations. They include, more recently: (1) The "BEIR VII Phase 2" report from the NRC's Committee on Biological Effects of Ionizing Radiation (BEIR) (NRC, 2006); (2) Studies of Radiation and Cancer from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2006), (3) The 2007 Recommendations of the International Commission on Radiological Protection (ICRP), ICRP Publication 103 (ICRP, 2007); and (4) The Environmental Protection Agency s (EPA s) report EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population (EPA, 2011). The approaches described in the reports from all of these expert groups are quite similar. NASA's proposed space radiation cancer risk assessment model calculates, as its main output, age- and gender-specific risk of exposure-induced death (REID) for use in the estimation of mission and astronaut-specific cancer risk. The model also calculates the associated uncertainties in REID. The general approach for

  19. Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

    NASA Astrophysics Data System (ADS)

    Priharti, W.; Samat, S. B.; Yasir, M. S.

    2015-09-01

    The radionuclides of 226Ra, 232Th and 40K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10-3 (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottled mineral water produced in Malaysia is safe for daily human consumption.

  20. Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

    SciTech Connect

    Priharti, W.; Samat, S. B.; Yasir, M. S.

    2015-09-25

    The radionuclides of {sup 226}Ra, {sup 232}Th and {sup 40}K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10{sup −3} (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottled mineral water produced in Malaysia is safe for daily human consumption.

  1. Cytogenetic examination of cosmonauts for space radiation exposure estimation

    NASA Astrophysics Data System (ADS)

    Snigiryova, G. P.; Novitskaya, N. N.; Fedorenko, B. S.

    2012-08-01

    PurposeTo evaluate radiation induced chromosome aberration frequency in peripheral blood lymphocytes of cosmonauts who participated in flights on Mir Orbital Station and ISS (International Space Station). Materials and methodsCytogenetic examination which has been performed in the period 1992-2008 included the analysis of chromosome aberrations using conventional Giemsa staining method in 202 blood samples from 48 cosmonauts who participated in flights on Mir Orbital Station and ISS. ResultsSpace flights led to an increase of chromosome aberration frequency. Frequency of dicentrics plus centric rings (Dic+Rc) depend on the space flight duration and accumulated dose value. After the change of space stations (from Mir Orbital Station to ISS) the radiation load of cosmonauts based on data of cytogenetic examination decreased. Extravehicular activity also adds to chromosome aberration frequency in cosmonauts' blood lymphocytes. Average doses after the first flight, estimated by the frequency of Dic+Rc, were 227 and 113 mGy Eq for long-term flights (LTF) and 107 and 53 mGy Eq for short-term flights (STF). ConclusionCytogenetic examination of cosmonauts can be applied to assess equivalent doses.

  2. Assessment of radiation-induced second cancer risks in proton therapy and IMRT for organs inside the primary radiation field.

    PubMed

    Paganetti, Harald; Athar, Basit S; Moteabbed, Maryam; A Adams, Judith; Schneider, Uwe; Yock, Torunn I

    2012-10-07

    There is clinical evidence that second malignancies in radiation therapy occur mainly within the beam path, i.e. in the medium or high-dose region. The purpose of this study was to assess the risk for developing a radiation-induced tumor within the treated volume and to compare this risk for proton therapy and intensity-modulated photon therapy (IMRT). Instead of using data for specific patients we have created a representative scenario. Fully contoured age- and gender-specific whole body phantoms (4 year and 14 year old) were uploaded into a treatment planning system and tumor volumes were contoured based on patients treated for optic glioma and vertebral body Ewing's sarcoma. Treatment plans for IMRT and proton therapy treatments were generated. Lifetime attributable risks (LARs) for developing a second malignancy were calculated using a risk model considering cell kill, mutation, repopulation, as well as inhomogeneous organ doses. For standard fractionation schemes, the LAR for developing a second malignancy from radiation therapy alone was found to be up to 2.7% for a 4 year old optic glioma patient treated with IMRT considering a soft-tissue carcinoma risk model only. Sarcoma risks were found to be below 1% in all cases. For a 14 year old, risks were found to be about a factor of 2 lower. For Ewing's sarcoma cases the risks based on a sarcoma model were typically higher than the carcinoma risks, i.e. LAR up to 1.3% for soft-tissue sarcoma. In all cases, the risk from proton therapy turned out to be lower by at least a factor of 2 and up to a factor of 10. This is mainly due to lower total energy deposited in the patient when using proton beams. However, the comparison of a three-field and four-field proton plan also shows that the distribution of the dose, i.e. the particular treatment plan, plays a role. When using different fractionation schemes, the estimated risks roughly scale with the total dose difference in%. In conclusion, proton therapy can

  3. Papillary Microcarcinoma of the Thyroid among Atomic Bomb Survivors: Tumor Characteristics and Radiation Risk

    PubMed Central

    Hayashi, Yuzo; Lagarde, Frederic; Tsuda, Nobuo; Funamoto, Sachiyo; Preston, Dale L.; Koyama, Kojiro; Mabuchi, Kiyohiko; Ron, Elaine; Kodama, Kazunori; Tokuoka, Shoji

    2009-01-01

    Background Radiation exposure is an established cause of clinical thyroid cancer, but little is known about radiation effects on papillary microcarcinoma (PMC) of the thyroid, a relatively common subclinical thyroid malignancy. Because the incidence of these small thyroid cancers has been increasing, it is important to better understand them and their relationship to radiation. Methods PMCs were identified in a subset of 7659 members of the Life Span Study of atomic-bomb survivors who had archived autopsy or surgical materials. We conducted a pathology review of these specimens and evaluated the histological features of the tumors and the association between PMCs and thyroid radiation dose. Results From 1958 to1995, 458 PMCs were detected among 313 study subjects. The majority of cancers exhibited pathologic features of papillary thyroid cancers. Overall, 81% of the PMCs were of the sclerosing variant and 91% were nonencapsulated, psammoma bodies occurred in 13% and calcification was observed in 23%. Over 95% had papillary or papillary-follicular architecture and most displayed nuclear overlap, clear nuclei, and nuclear grooves. Several of these features increased with increasing tumor size, but no association was found with radiation dose. A significant radiation-dose response was found for the prevalence of PMCs (estimated excess odds ratio/Gy=0.57; 95% CI: 0.01-1.55), with the excess risk observed primarily among females. Conclusion Low-to-moderate doses of ionizing radiation appears to increase the risk of thyroid PMCs, even when exposure occurs during adulthood. PMID:20120034

  4. Biological-Based Modeling of Low Dose Radiation Risks

    SciTech Connect

    Scott, Bobby R., Ph.D.

    2006-11-08

    The objective of this project was to refine a biological-based model (called NEOTRANS2) for low-dose, radiation-induced stochastic effects taking into consideration newly available data, including data on bystander effects (deleterious and protective). The initial refinement led to our NEOTRANS3 model which has undergone further refinement (e.g., to allow for differential DNA repair/apoptosis over different dose regions). The model has been successfully used to explain nonlinear dose-response curves for low-linear-energy-transfer (LET) radiation-induced mutations (in vivo) and neoplastic transformation (in vitro). Relative risk dose-response functions developed for neoplastic transformation have been adapted for application to cancer relative risk evaluation for irradiated humans. Our low-dose research along with that conducted by others collectively demonstrate the following regarding induced protection associated with exposure to low doses of low-LET radiation: (1) protects against cell killing by high-LET alpha particles; (2) protects against spontaneous chromosomal damage; (3) protects against spontaneous mutations and neoplastic transformations; (4) suppresses mutations induced by a large radiation dose even when the low dose is given after the large dose; (5) suppresses spontaneous and alpha-radiation-induced cancers; (6) suppresses metastasis of existing cancer; (7) extends tumor latent period; (8) protects against diseases other than cancer; and (9) extends life expectancy. These forms of radiation-induced protection are called adapted protection as they relate to induced adaptive response. Thus, low doses and dose rates of low-LET radiation generally protect rather than harm us. These findings invalidate the linear not threshold (LNT) hypothesis which is based on the premise that any amount of radiation is harmful irrespective of its type. The hypothesis also implicates a linear dose-response curve for cancer induction that has a positive slope and no

  5. [Exposure to ionizing radiation from computed tomography (CT) in childhood and cancer risk].

    PubMed

    Gianicolo, Emilio Antonio Luca; Pokora, Roman; Krille, Lucian; Blettner, Maria

    2016-01-01

    A recent US cohort study estimated 500 cancer cases attributable to exposure to CT out of 600,000 children aged <15 years who underwent a computed tomography (CT) to head or abdomen. This review synthetizes the evidence on the association between exposure to ionizing radiation through CT and cancer risk. Five cohort studies were identified. Three studies show clear increases in cancer risk among children and adolescents who underwent at least one CT. All studies had methodological limits, among which the lack of an individual level estimate of dose-organ specific absorbed by patient and problems of statistical power. Results from on-going large international studies will allow a more accurate risk estimation.

  6. Sensitivity of health risk estimates to air quality adjustment procedure

    SciTech Connect

    Whitfield, R.G.

    1997-06-30

    This letter is a summary of risk results associated with exposure estimates using two-parameter Weibull and quadratic air quality adjustment procedures (AQAPs). New exposure estimates were developed for children and child-occurrences, six urban areas, and five alternative air quality scenarios. In all cases, the Weibull and quadratic results are compared to previous results, which are based on a proportional AQAP.

  7. Impact of the 1980 BEIR-III report on low-level radiation risk assessment, radiation protection guides, and public health policy

    SciTech Connect

    Fabrikant, J.I.

    1981-06-01

    The author deals with the scientific basis for establishing appropriate radiation protection guides, and this effect on evaluation of societal activities concerned with the health effects in human populations exposed to low-level radiation. Methodology is discussed for estimating risks of radio-induced cancer and genetically related ill-health in man, the sources of data, the dose-response models used, and the precision ascribed to the process. (PSB)

  8. Impact on radiogenic cancer risk of persons exhibiting abnormal sensitivity to ionizing radiation

    SciTech Connect

    Gentner, N.E.; Morrison, D.P.; Myers, D.K.

    1988-08-01

    Human genotypes are known that confer both increased susceptibility or resistance to DNA damage and increased cancer risk after exposure to carcinogenic agents, including ionizing radiation (NAS 1980). The existence of sensitive subgroups at elevated risk, if they are of appreciable size, could have significant impact on the actual distribution of risk. The radiosensitive disorder ataxia-telangiectasia (A-T) serves as a good example: the significant at risk group, A-T heterozygotes, is estimated to comprise between 0.5% and 5% of the total population, and has a twofold elevated lifetime risk of fatal neoplasia. Other genetic syndromes that manifest abnormal radiosensitivity are also known, but no estimates are available for the population frequency of all such phenotypes, or for their overall degree of increased risk. As the first part of a program addressing these questions, we have developed a rapid and inexpensive assay for screening members of the general population for abnormal radiosensitivity; such persons would be regarded as at presumptive elevated risk of radiogenic cancer. Our method utilizes lymphoblastoid cell lines and chronic as opposed to acute gamma-ray exposure to amplify the difference between normal and somewhat sensitive strains. A simple grow-back assay assesses the survival response. Information on the extent of natural variation in inherited susceptibility to radiogenic cancers could be most useful for radiation protection in the future.

  9. Methodology for Estimating Radiation Dose Rates to Freshwater Biota Exposed to Radionuclides in the Environment

    SciTech Connect

    Blaylock, B.G.

    1993-01-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h{sup -1} (1 rad d{sup -1}). A dose rate no greater than 0.4 mGy h{sup -1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). The literature identifies the developing eggs and young of some species of teleost fish as the most radiosensitive organisms. DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0.1 mGy h{sup -1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be

  10. Non-Radiation Risk Factors for Leukemia: A case-control study among Chornobyl Cleanup Workers in Ukraine

    PubMed Central

    Gudzenko, Nataliya; Hatch, Maureen; Bazyka, Dimitry; Dyagil, Irina; Reiss, Robert F; Brenner, Alina; Chumak, Vadim; Babkina, Natalie; Zablotska, Lydia B; Mabuchi, Kiyohiko

    2015-01-01

    Background Occupational and environmental exposure to chemicals such as benzene has been linked to increased risk of leukemia. Cigarette smoking and alcohol consumption have also been found to affect leukemia risk. Previous analyses in a large cohort of Chornobyl clean-up workers in Ukraine found significant radiation-related increased risk for all leukemia types. We investigated the potential for additional effects of occupational and lifestyle factors on leukemia risk in this radiation-exposed cohort. Methods In a case-control study of chronic lymphocytic and other leukemias among Chornobyl cleanup workers, we collected data on a range of non-radiation exposures. We evaluated these other potential risk factors in analyses adjusting for estimated bone marrow radiation dose. We calculated Odds Ratios and 95% Confidence Intervals in relation to lifestyle factors and occupational hazards. Results After adjusting for radiation, we found no clear association of leukemia risk with smoking or alcohol but identified a two-fold elevated risk for non-CLL leukemia with occupational exposure to petroleum (OR=2.28; 95% Confidence Interval 1.13, 6.79). Risks were particularly high for myeloid leukemias. No associations with risk factors other than radiation were found for chronic lymphocytic leukemia. Conclusions These data – the first from a working population in Ukraine – add to evidence from several previous reports of excess leukemia morbidity in groups exposed environmentally or occupationally to petroleum or its products. PMID:26117815

  11. Improved aerosol radiative properties as a foundation for solar geoengineering risk assessment

    NASA Astrophysics Data System (ADS)

    Dykema, J. A.; Keith, D. W.; Keutsch, F. N.

    2016-07-01

    Side effects resulting from the deliberate injection of sulfate aerosols intended to partially offset climate change have motivated the investigation of alternatives, including solid aerosol materials. Sulfate aerosols warm the tropical tropopause layer, increasing the flux of water vapor into the stratosphere, accelerating ozone loss, and increasing radiative forcing. The high refractive index of some solid materials may lead to reduction in these risks. We present a new analysis of the scattering efficiency and absorption of a range of candidate solid aerosols. We utilize a comprehensive radiative transfer model driven by updated, physically consistent estimates of optical properties. We compute the potential increase in stratospheric water vapor and associated longwave radiative forcing. We find that the stratospheric heating calculated in this analysis indicates some materials to be substantially riskier than previous work. We also find that there are Earth-abundant materials that may reduce some principal known risks relative to sulfate aerosols.

  12. Animal studies of life shortening and cancer risk from space radiation

    NASA Astrophysics Data System (ADS)

    Wood, D. H.; Yochmowitz, M. G.; Hardy, K. A.; Salmon, Y. L.

    The U. S. Air Force study of the delayed effects of single, total body exposures to simulated space radiation in rhesus monkeys is now in its 21st year. Observations on 301 irradiated and 57 age-matched control animals indicate that life expectancy loss from exposure to protons in the energy range encountered in the Van Allen belts and solar proton events can be expressed as a logarithmic function of the dose. The primary causes of life shortening are cancer and endometriosis (an abnormal proliferation of the lining of the uterus in females). Life shortening estimates permit comparison of the risk associated with space radiation exposures to be compared with that of other occupational and environmental hazards, thereby facilitating risk/benefit decisions in the planning and operational phases of manned space missions. Calculations of the relative risk of fatal cancers in the irradiated subjects reveal that the total body surface dose required to double the risk of death from cancer over a 20-year post exposure period varies with the linear energy transfer (LET) of the radiation. The ability to determine the integrated dose and LET spectrum in space radiation exposures of human is, therefore, critical to the assessment of life-time cancer risk.

  13. Radiation risk from fluoroscopically-assisted anterior cruciate ligament reconstruction

    PubMed Central

    Chitnavis, JP; Karthikesaligam, A; Macdonald, A; Brown, C

    2010-01-01

    INTRODUCTION Precise tunnel positioning is crucial for success in anterior cruciate ligament (ACL) reconstruction. The use of intra-operative fluoroscopy has been shown to improve the accuracy of tunnel placement. Although radiation exposure is a concern, we lack information on the radiation risk to patients undergoing fluoroscopically-assisted ACL reconstruction with a standard C-arm. The aim of our study was to determine the mean radiation doses received by our patients. PATIENTS AND METHODS Radiation doses were recorded for 18 months between 1 April 2007 and 30 September 2008 for 58 consecutive patients undergoing ACL reconstruction assisted by intra-operative fluoroscopy. Dose area product (DAP) values were used to calculate the entrance skin dose (ESD), an indicator of potential skin damage and the effective dose (ED), an indicator of long-term cancer risk, for each patient. RESULTS The median age of 58 patients included in data analysis was 28 years (range, 14–52 years), of whom 44 were male (76%). The mean ESD during intra-operative fluoroscopy was 0.0015 ± 0.0029 Gy. The mean ED was 0.001 ± 0.002 mSv. No results exceeded the threshold of 2 Gy for skin damage, and the life-time risk of developing new cancer due to intra-operative fluoroscopy is less than 0.0001%. CONCLUSIONS Radiation doses administered during fluoroscopically-assisted ACL reconstruction were safe and do not represent a contra-indication to the procedure. PMID:20501019

  14. Estimation of photosynthetically active radiation absorbed at the surface

    NASA Astrophysics Data System (ADS)

    Li, Zhanqing; Moreau, Louis; Cihlar, Josef

    1997-12-01

    This paper presents a validation and application of an algorithm by Li and Moreau [1996] for retrieving photosynthetically active radiation (PAR) absorbed at the surface (APARSFC). APARSFC is a key input to estimating PAR absorbed by the green canopy during photosynthesis. Extensive ground-based and space-borne observations collected during the BOREAS experiment in 1994 were processed, colocated, and analyzed. They include downwelling and upwelling PAR observed at three flux towers, aerosol optical depth from ground-based photometers, and satellite reflectance measurements at the top of the atmosphere. The effects of three-dimensional clouds, aerosols, and bidirectional dependence on the retrieval of APARSFC were examined. While the algorithm is simple and has only three input parameters, the comparison between observed and estimated APARSFC shows a small bias error (<10 W m-2) and moderate random error (36 W m-2 for clear, 61 W m-2 for cloudy). Temporal and/or spatial mismatch between satellite and surface observations is a major cause of the random error, especially when broken clouds are present. The algorithm was subsequently employed to map the distribution of monthly mean APARSFC over the 1000×1000 km2 BOREAS region. Considerable spatial variation is found due to variable cloudiness, forest fires, and nonuniform surface albedo.

  15. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    NASA Astrophysics Data System (ADS)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  16. Improved fire radiative energy estimation in high latitude ecosystems

    NASA Astrophysics Data System (ADS)

    Melchiorre, A.; Boschetti, L.

    2014-12-01

    Scientists, land managers, and policy makers are facing new challenges as fire regimes are evolving as a result of climate change (Westerling et al. 2006). In high latitudes fires are increasing in number and size as temperatures increase and precipitation decreases (Kasischke and Turetsky 2006). Peatlands, like the large complexes in the Alaskan tundra, are burning more frequently and severely as a result of these changes, releasing large amounts of greenhouse gases. Remotely sensed data are routinely used to monitor the location of active fires and the extent of burned areas, but they are not sensitive to the depth of the organic soil layer combusted, resulting in underestimation of peatland greenhouse gas emissions when employing the conventional 'bottom up' approach (Seiler and Crutzen 1980). An alternative approach would be the direct estimation of the biomass burned from the energy released by the fire (Fire Radiative Energy, FRE) (Wooster et al. 2003). Previous works (Boschetti and Roy 2009; Kumar et al. 2011) showed that the sampling interval of polar orbiting satellite systems severely limits the accuracy of the FRE in tropical ecosystems (up to four overpasses a day with MODIS), but because of the convergence of the orbits, more observations are available at higher latitudes. In this work, we used a combination of MODIS thermal data and Landsat optical data for the estimation of biomass burned in peatland ecosystems. First, the global MODIS active fire detection algorithm (Giglio et al. 2003) was modified, adapting the temperature thresholds to maximize the number of detections in boreal regions. Then, following the approach proposed by Boschetti and Roy (2009), the FRP point estimations were interpolated in time and space to cover the full temporal and spatial extent of the burned area, mapped with Landsat5 TM data. The methodology was tested on a large burned area in Alaska, and the results compared to published field measurements (Turetsky et al. 2011).

  17. Estimating the re-identification risk of clinical data sets

    PubMed Central

    2012-01-01

    Background De-identification is a common way to protect patient privacy when disclosing clinical data for secondary purposes, such as research. One type of attack that de-identification protects against is linking the disclosed patient data with public and semi-public registries. Uniqueness is a commonly used measure of re-identification risk under this attack. If uniqueness can be measured accurately then the risk from this kind of attack can be managed. In practice, it is often not possible to measure uniqueness directly, therefore it must be estimated. Methods We evaluated the accuracy of uniqueness estimators on clinically relevant data sets. Four candidate estimators were identified because they were evaluated in the past and found to have good accuracy or because they were new and not evaluated comparatively before: the Zayatz estimator, slide negative binomial estimator, Pitman’s estimator, and mu-argus. A Monte Carlo simulation was performed to evaluate the uniqueness estimators on six clinically relevant data sets. We varied the sampling fraction and the uniqueness in the population (the value being estimated). The median relative error and inter-quartile range of the uniqueness estimates was measured across 1000 runs. Results There was no single estimator that performed well across all of the conditions. We developed a decision rule which selected between the Pitman, slide negative binomial and Zayatz estimators depending on the sampling fraction and the difference between estimates. This decision rule had the best consistent median relative error across multiple conditions and data sets. Conclusion This study identified an accurate decision rule that can be used by health privacy researchers and disclosure control professionals to estimate uniqueness in clinical data sets. The decision rule provides a reliable way to measure re-identification risk. PMID:22776564

  18. Model-based Small Area Estimates of Cancer Risk Factors and Screening Behaviors - Small Area Estimates

    Cancer.gov

    These model-based estimates use two surveys, the Behavioral Risk Factor Surveillance System (BRFSS) and the National Health Interview Survey (NHIS). The two surveys are combined using novel statistical methodology.

  19. Position of cytogenetic examination of cosmonauts for the space radiation expose estimate

    NASA Astrophysics Data System (ADS)

    Snigireva, Galina; Novitskaya, Natalia; Ivanov, Alexander

    Analysis of chromosome aberrations in human peripheral blood lymphocytes is widely used for the indication and quantitative assessment of radiation. The dose, as estimated by the frequency of chromosome aberrations takes into account not only the physical impact of radiation on the human body but also its individual characteristics, such as radiation sensitivity and functional conditions during irradiation. The purpose of this study was to evaluate the influence of radiation on the chromosome aberration frequency in peripheral blood lymphocytes of the cosmonauts who participated in flights on the ISS (International Space Station). Cytogenetic examination was performed in the period 1992-2013 and included the analysis of chromosome aberrations using conventional Giemsa staining method in blood samples from 38 cosmonauts who participated in flights on the ISS. The cytogenetic examination results showed that cosmic flights lead to an increase of chromosome aberrations in the lymphocytes of cosmonauts. Compared with the pre-flight levels frequencies of dicentrics and centric rings (the radiation exposure markers) are about 4 times higher for cosmonauts after flights. The frequency of chromosome aberrations depends on the length of the flight and, correspondingly, on the accumulated dose of cosmic irradiation. Between flights, a decrease in the chromosome aberration frequency is observed, but even several years after a flight, the level of chromosome aberrations in the lymphocytes of cosmonauts remains high. Cytogenetic monitoring of cosmonauts can undoubtedly play an important role in comprehensive medical surveys of these individuals if we take into account the possible connection of higher levels of chromosomal aberrations with the risk of oncological diseases. Analysis of chromosome aberration dynamics after flights will allow the determination of individuals with an increased cancerogenese risk and provision of required treatments.

  20. [Update - health risks induced by ionizing radiation from diagnostic imaging].

    PubMed

    Knüsli, Claudio; Walter, Martin

    2013-12-01

    Ionizing radiation is the most thoroughly investigated exogenous noxa. Since the early 20th century it is well known that using ionizing radiation in diagnostic procedures causes cancer - physicians themselves frequently being struck by this disease in those early days of radiology. Radiation protection therefore plays an important role. Below doses of 100 Millisievert (mSv) however much research has to be accomplished yet because not only malignant tumors, but cardiovascular diseases, malformations and genetic sequelae attributable to low dose radiation have been described. Unborns, children and adolescents are highly vulnerable. Dose response correlations are subject to continuing discussions because data stem mostly from calculations studying Japanese atomic bomb survivors. Radiation exposure is not exactly known, and it is unknown, if observations of radiation induced diseases in this ethnicity can be generalized. Nowadays the main source of low dose ionizing radiation from medical diagnostics is due to computertomography (CT). Large recent clinical studies from the UK and Australia investigating cancer incidence after exposition to CT in childhood and adolescence confirm that low doses in the range of 5 mSv already significantly increase the risk of malignant diseases during follow up. Imaging techniques as ultrasound and magnetic resonance tomography therefore should be preferred whenever appropriate.

  1. [Occupational risk related to optical radiation exposure in construction workers].

    PubMed

    Gobba, F; Modenese, A

    2012-01-01

    Optical Radiation is a relevant occupational risk in construction workers, mainly as a consequence of the exposure to the ultraviolet (UV) component of solar radiation (SR). Available data show that UV occupational limits are frequently exceeded in these workers, resulting in an increased occupational risk of various acute and chronic effects, mainly to skin and to the eye. One of the foremost is the carcinogenic effect: SR is indeed included in Group 1 IARC (carcinogenic to humans). UV exposure is related to an increase of the incidence of basal cell carcinoma, squamous cell carcinoma of the skin and cutaneous malignant melanoma (CMM). The incidence of these tumors, especially CMM, is constantly increasing in Caucasians in the last 50 years. As a conclusion, an adequate evaluation of the occupational risk related to SR, and adequate preventive measures are essential in construction workers. The role of occupational physicians in prevention is fundamental.

  2. Estimating and Mapping the Population at Risk of Sleeping Sickness

    PubMed Central

    Franco, José R.; Paone, Massimo; Diarra, Abdoulaye; Ruiz-Postigo, José Antonio; Fèvre, Eric M.; Mattioli, Raffaele C.; Jannin, Jean G.

    2012-01-01

    Background Human African trypanosomiasis (HAT), also known as sleeping sickness, persists as a public health problem in several sub-Saharan countries. Evidence-based, spatially explicit estimates of population at risk are needed to inform planning and implementation of field interventions, monitor disease trends, raise awareness and support advocacy. Comprehensive, geo-referenced epidemiological records from HAT-affected countries were combined with human population layers to map five categories of risk, ranging from “very high” to “very low,” and to estimate the corresponding at-risk population. Results Approximately 70 million people distributed over a surface of 1.55 million km2 are estimated to be at different levels of risk of contracting HAT. Trypanosoma brucei gambiense accounts for 82.2% of the population at risk, the remaining 17.8% being at risk of infection from T. b. rhodesiense. Twenty-one million people live in areas classified as moderate to very high risk, where more than 1 HAT case per 10,000 inhabitants per annum is reported. Discussion Updated estimates of the population at risk of sleeping sickness were made, based on quantitative information on the reported cases and the geographic distribution of human population. Due to substantial methodological differences, it is not possible to make direct comparisons with previous figures for at-risk population. By contrast, it will be possible to explore trends in the future. The presented maps of different HAT risk levels will help to develop site-specific strategies for control and surveillance, and to monitor progress achieved by ongoing efforts aimed at the elimination of sleeping sickness. PMID:23145192

  3. Estimating cancer risk from dental cone-beam CT exposures based on skin dosimetry

    NASA Astrophysics Data System (ADS)

    Pauwels, Ruben; Cockmartin, Lesley; Ivanauskaité, Deimante; Urbonienė, Ausra; Gavala, Sophia; Donta, Catherine; Tsiklakis, Kostas; Jacobs, Reinhilde; Bosmans, Hilde; Bogaerts, Ria; Horner, Keith; SEDENTEXCT Project Consortium, The

    2014-07-01

    The aim of this study was to measure entrance skin doses on patients undergoing cone-beam computed tomography (CBCT) examinations, to establish conversion factors between skin and organ doses, and to estimate cancer risk from CBCT exposures. 266 patients (age 8-83) were included, involving three imaging centres. CBCT scans were acquired using the SCANORA 3D (Soredex, Tuusula, Finland) and NewTom 9000 (QR, Verona, Italy). Eight thermoluminescent dosimeters were attached to the patient's skin at standardized locations. Using previously published organ dose estimations on various CBCTs with an anthropomorphic phantom, correlation factors to convert skin dose to organ doses were calculated and applied to estimate patient organ doses. The BEIR VII age- and gender-dependent dose-risk model was applied to estimate the lifetime attributable cancer risk. For the SCANORA 3D, average skin doses over the eight locations varied between 484 and 1788 µGy. For the NewTom 9000 the range was between 821 and 1686 µGy for Centre 1 and between 292 and 2325 µGy for Centre 2. Entrance skin dose measurements demonstrated the combined effect of exposure and patient factors on the dose. The lifetime attributable cancer risk, expressed as the probability to develop a radiation-induced cancer, varied between 2.7 per million (age >60) and 9.8 per million (age 8-11) with an average of 6.0 per million. On average, the risk for female patients was 40% higher. The estimated radiation risk was primarily influenced by the age at exposure and the gender, pointing out the continuing need for justification and optimization of CBCT exposures, with a specific focus on children.

  4. Estimating cancer risk from dental cone-beam CT exposures based on skin dosimetry.

    PubMed

    Pauwels, Ruben; Cockmartin, Lesley; Ivanauskaité, Deimante; Urbonienė, Ausra; Gavala, Sophia; Donta, Catherine; Tsiklakis, Kostas; Jacobs, Reinhilde; Bosmans, Hilde; Bogaerts, Ria; Horner, Keith

    2014-07-21

    The aim of this study was to measure entrance skin doses on patients undergoing cone-beam computed tomography (CBCT) examinations, to establish conversion factors between skin and organ doses, and to estimate cancer risk from CBCT exposures. 266 patients (age 8-83) were included, involving three imaging centres. CBCT scans were acquired using the SCANORA 3D (Soredex, Tuusula, Finland) and NewTom 9000 (QR, Verona, Italy). Eight thermoluminescent dosimeters were attached to the patient's skin at standardized locations. Using previously published organ dose estimations on various CBCTs with an anthropomorphic phantom, correlation factors to convert skin dose to organ doses were calculated and applied to estimate patient organ doses. The BEIR VII age- and gender-dependent dose-risk model was applied to estimate the lifetime attributable cancer risk. For the SCANORA 3D, average skin doses over the eight locations varied between 484 and 1788 µGy. For the NewTom 9000 the range was between 821 and 1686 µGy for Centre 1 and between 292 and 2325 µGy for Centre 2. Entrance skin dose measurements demonstrated the combined effect of exposure and patient factors on the dose. The lifetime attributable cancer risk, expressed as the probability to develop a radiation-induced cancer, varied between 2.7 per million (age >60) and 9.8 per million (age 8-11) with an average of 6.0 per million. On average, the risk for female patients was 40% higher. The estimated radiation risk was primarily influenced by the age at exposure and the gender, pointing out the continuing need for justification and optimization of CBCT exposures, with a specific focus on children.

  5. Perception of radiation dose and potential risks of computed tomography in emergency department medical personnel

    PubMed Central

    Lee, Jin Hee; Kim, Kyuseok; Lee, Kyoung Ho; Kim, Kwang Pyo; Kim, Yu Jin; Park, Chanjong; Kang, Changwoo; Lee, Soo Hoon; Jeong, Jin Hee; Rhee, Joong Eui

    2015-01-01

    Objective Use of computed tomography (CT) continues to increase, but the relatively high radiation doses associated with CT have raised health concerns such as future risk of cancer. We investigated the level of awareness regarding radiation doses and possible risks associated with CT in medical personnel (MP). Methods This study was conducted from April to May 2012 and included physicians and nurses who worked in the emergency department of 17 training hospitals. The questionnaire included measurement of the effect of CT or radiography on health using a 10-point numerical rating scale, estimation of the radiation dose of one abdominal CT scan compared with one chest radiograph, and perception of the increased lifetime risk of cancer associated with CT. Results A total of 354 MP participated in this study: 142 nurses, 87 interns, 86 residents, and 39 specialists. Interns were less aware of the effects of CT or radiography on health than other physicians or nurses (mean±SD of 4.8±2.7, 5.9±2.7, 6.1±2.7, and 6.0±2.2 for interns, residents, specialists, and nurses, respectively; P<0.05). There was a significant difference in knowledge about the relative radiation dose of one abdominal CT scan compared with one chest radiograph between physicians and nurses (48.6% vs. 28.9% for physicians vs. nurses, P<0.05). MP perceived an increased risk of cancer from radiation associated with CT. Conclusion MP perceive the risk of radiation associated with CT, but their level of knowledge seems to be insufficient. PMID:27752583

  6. Risk estimates for deterministic health effects of inhaled weapons grade plutonium.

    PubMed

    Scott, Bobby R; Peterson, Vern L

    2003-09-01

    Risk estimates for deterministic effects of inhaled weapons-grade plutonium (WG Pu) are needed to evaluate potential serious harm to (1) U.S. Department of Energy nuclear workers from accidental or other work-place releases of WG Pu; and (2) the public from terrorist actions resulting in the release of WG Pu to the environment. Deterministic health effects (the most serious radiobiological consequences to humans) can arise when large amounts of WG Pu are taken into the body. Inhalation is considered the most likely route of intake during work-place accidents or during a nuclear terrorism incident releasing WG Pu to the environment. Our current knowledge about radiation-related harm is insufficient for generating precise estimates of risk for a given WG Pu exposure scenario. This relates largely to uncertainties associated with currently available risk and dosimetry models. Thus, rather than generating point estimates of risk, distributions that account for variability/uncertainty are needed to properly characterize potential harm to humans from a given WG Pu exposure scenario. In this manuscript, we generate and summarize risk distributions for deterministic radiation effects in the lungs of nuclear workers from inhaled WG Pu particles (standard isotopic mix). These distributions were developed using NUREG/CR-4214 risk models and time-dependent, dose conversion factor data based on Publication 30 of the International Commission on Radiological Protection. Dose conversion factors based on ICRP Publication 30 are more relevant to deterministic effects than are the dose conversion factors based on ICRP Publication 66, which relate to targets for stochastic effects. Risk distributions that account for NUREG/CR-4214 parameter and model uncertainties were generated using the Monte Carlo method. Risks were evaluated for both lethality (from radiation pneumonitis) and morbidity (due to radiation-induced respiratory dysfunction) and were found to depend strongly on absorbed

  7. Multistage Carcinogenesis Modelling of Low and Protracted Radiation Exposure for Risk Assessment

    NASA Astrophysics Data System (ADS)

    Brugmans, M. J. P.; Bijwaard, H.

    Exposure to cosmic radiation in space poses an increased risk for radiation-induced cancer later in life. Modelling is essential to quantify these excess risks from low and protracted exposures to a mixture of radiation types, since they cannot be determined directly in epidemiological studies. Multistage carcinogenesis models provide a mechanistic basis for the extrapolation of epidemiological data to the regime that is relevant for radiation protection. In recent years, we have exploited the well-known two-mutation carcinogenesis model to bridge the gap between radiobiology and epidemiology. We have fitted this model to a number of animal and epidemiological data sets, using dose-response relationships for the mutational steps that are well established in cellular radiobiology. The methodology and implications for radiation risks are illustrated with analyses of two radiation-induced tumours: bone cancer from internal (high-LET and low-LET) emitters and lung cancer after radon exposure. For the risks of bone-seeking radionuclides (Ra-226, Sr-90, Pu-239), model fits to beagle data show that the dose-effect relationship for bone cancer at low intakes is linear-quadratic. This is due to a combination of equally strong linear dose-effects in the two subsequent mutational steps in the model. This supra-linear dose-effect relationship is also found in a model analysis of bone cancer in radium dial painters. This implies that at low intakes the risks from bone seekers are significantly lower than estimated from a linear extrapolation from high doses. Model analyses of radon-exposed rats and uranium miners show that lung-cancer induction is dominated by a linear radiation effect in the first mutational step. For two miner cohorts with significantly different lung cancer baselines a uniform description of the effect of radon is obtained in a joint analysis. This demonstrates the possibility to model risk transfer across populations. In addition to biologically based risk

  8. Radiation Dose-Response Relationships and Risk Assessment

    SciTech Connect

    Strom, Daniel J.

    2005-07-05

    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

  9. Evidence Report: Risk of Acute Radiation Syndromes Due to Solar Particle Events

    NASA Technical Reports Server (NTRS)

    Carnell, Lisa; Blattnig, Steve; Hu, Shaowen; Huff, Janice; Kim, Myung-Hee; Norman, Ryan; Patel, Zarana; Simonsen, Lisa; Wu, Honglu

    2016-01-01

    Crew health and performance may be impacted by a major solar particle event (SPE), multiple SPEs, or the cumulative effect of galactic cosmic rays (GCR) and SPEs. Beyond low-Earth orbit, the protection of the Earth's magnetosphere is no longer available, such that increased shielding and protective mechanisms are necessary in order to prevent acute radiation sickness and impacts to mission success or crew survival. While operational monitoring and shielding are expected to minimize radiation exposures, there are EVA scenarios outside of low-Earth orbit where the risk of prodromal effects, including nausea, vomiting, anorexia, and fatigue, as well as skin injury and depletion of the blood-forming organs (BFO), may occur. There is a reasonable concern that a compromised immune system due to high skin doses from a SPE or due to synergistic space flight factors (e.g., microgravity) may lead to increased risk to the BFO. The primary data available at present are derived from analyses of medical patients and persons accidentally exposed to acute, high doses of low-linear energy transfer (LET) (or terrestrial) radiation. Data more specific to the space flight environment must be compiled to quantify the magnitude of increase of this risk and to develop appropriate protection strategies. In particular, information addressing the distinct differences between solar proton exposures and terrestrial exposure scenarios, including radiation quality, dose-rate effects, and non-uniform dose distributions, is required for accurate risk estimation.

  10. Prophylactic radiotherapy against heterotopic ossification following internal fixation of acetabular fractures: a comparative estimate of risk

    PubMed Central

    Nasr, P; Yip, G; Scaife, J E; House, T; Thomas, S J; Harris, F; Owen, P J; Hull, P

    2014-01-01

    Objective: Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis. Methods: 34 patients underwent reconstruction of acetabular fractures through a posterior approach, followed by a 8-Gy single fraction. The mean age was 44 years. The mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared with a method (Trott and Kemprad) specifically for estimating RT risk for benign disease. These were compared with risks associated with indometacin and no prophylaxis. Results: 28 patients (82%) developed no HO; 6 developed Brooker Class I; and none developed Class II–IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1 in 1000 to 1 in 10,000; the Trott and Kemprad method suggests 1 in 3000. For younger patients, this may rise to 1 in 2000; and for elderly patients, it may fall to 1 in 6000. The risk of death from gastric bleeding or perforation from indometacin is 1 in 180 to 1 in 900 in older patients. Without prophylaxis risk of death from reoperation to remove HO is 1 in 4000 to 1 in 30,000. Conclusion: These results are encouraging, consistent with much larger series and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients. Advances in knowledge: The risk from RT prophylaxis is small, it is safer than indometacin and substantially overlaps with the range for no prophylaxis. PMID:25089852

  11. Computation of thyroid doses and carcinogenic radiation risks to patients undergoing neck CT examinations.

    PubMed

    Huda, Walter; Spampinato, Maria V; Tipnis, Sameer V; Magill, Dennise

    2013-10-01

    The aim of the study was to investigate how differences in patient anatomy and CT technical factors in neck CT impact on thyroid doses and the corresponding carcinogenic risks. The CTDIvol and dose-length product used in 11 consecutive neck CT studies, as well as data on automatic exposure control (AEC) tube current variation(s) from the image DICOM header, were recorded. For each CT image that included the thyroid, the mass equivalent water cylinder was estimated based on the patient cross-sectional area and average relative attenuation coefficient (Hounsfield unit, HU). Patient thyroid doses were estimated by accounting for radiation intensity at the location of the patient's thyroid, patient size and the scan length. Thyroid doses were used to estimate thyroid cancer risks as a function of patient demographics using risk factors in BEIR VII. The length of the thyroid glands ranged from 21 to 54 mm with an average length of 42 ± 12 mm. Water cylinder diameters corresponding to the central slice through the patient thyroid ranged from 18 to 32 cm with a mean of 25 ± 5 cm. The average CTDIvol (32-cm phantom) used to perform these scans was 26 ± 6 mGy, but the use of an AEC increased the tube current by an average of 44 % at the thyroid mid-point. Thyroid doses ranged from 29 to 80 mGy, with an average of 55 ± 19 mGy. A 20-y-old female receiving the highest thyroid dose of 80 mGy would have a thyroid cancer risk of nearly 0.1 %, but radiation risks decreased very rapidly with increasing patient age. The key factors that affect thyroid doses in neck CT examinations are the radiation intensity at the thyroid location and the size of the patient. The corresponding patient thyroid cancer risk is markedly influenced by patient sex and age.

  12. Radiation exposure and risk assessment for critical female body organs

    NASA Technical Reports Server (NTRS)

    Atwell, William; Weyland, Mark D.; Hardy, Alva C.

    1991-01-01

    Space radiation exposure limits for astronauts are based on recommendations of the National Council on Radiation Protection and Measurements. These limits now include the age at exposure and sex of the astronaut. A recently-developed computerized anatomical female (CAF) model is discussed in detail. Computer-generated, cross-sectional data are presented to illustrate the completeness of the CAF model. By applying ray-tracing techniques, shield distribution functions have been computed to calculate absorbed dose and dose equivalent values for a variety of critical body organs (e.g., breasts, lungs, thyroid gland, etc.) and mission scenarios. Specific risk assessments, i.e., cancer induction and mortality, are reviewed.

  13. Space Radiation Cancer Risk Projections for Exploration Missions: Uncertainty Reduction and Mitigation

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis; Badhwar, Gautam; Saganti, Premkumar; Schimmerling, Walter; Wilson, John; Peterson, Leif; Dicello, John

    2002-01-01

    In this paper we discuss expected lifetime excess cancer risks for astronauts returning from exploration class missions. For the first time we make a quantitative assessment of uncertainties in cancer risk projections for space radiation exposures. Late effects from the high charge and energy (HZE) ions present in the galactic cosmic rays including cancer and the poorly understood risks to the central nervous system constitute the major risks. Methods used to project risk in low Earth orbit are seen as highly uncertain for projecting risks on exploration missions because of the limited radiobiology data available for estimating HZE ion risks. Cancer risk projections are described as a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Monte-Carlo sampling from subjective error distributions represents the lack of knowledge in each factor to quantify risk projection overall uncertainty. Cancer risk analysis is applied to several exploration mission scenarios. At solar minimum, the number of days in space where career risk of less than the limiting 3% excess cancer mortality can be assured at a 95% confidence level is found to be only of the order of 100 days.

  14. Cancer risk estimation of genotoxic chemicals based on target dose and a multiplicative model

    SciTech Connect

    Granath, F.N. . Dept. of Mathematical Statistics Karolinska Inst., Stockholm . Dept. of Medical Epidemiology); Vaca, C.E. . Dept. of Radiobiology Casco Products AB, Stockholm ); Ehrenberg, L.G.; Toernqvist, M.A. )

    1999-04-01

    A mechanistic model and associated procedures are proposed for cancer risk assessment of genotoxic chemicals. As previously shown for ionizing radiation, a linear multiplicative model was found to be compatible with published experimental data for ethylene oxide, acrylamide, and butadiene. Concurrent analysis led to rejection of an additive model. A reanalysis of data for radiogenic cancer in mouse, dog and man shows that the relative risk coefficient is approximately the same for tumors induced in the three species. Doses in vivo, defined as the time-integrated concentrations of ultimate mutagens, expressed in millimol x kg[sup [minus]1] x h (mMh) are, like radiation doses given in Gy or rad, proportional to frequencies of potentially mutagenic events. The radiation dose equivalents of chemical doses are, calculated by multiplying chemical doses (in mMh) with the relative genotoxic potencies determined in vitro. In this way the relative cancer incidence increments in rats and mice exposed to ethylene oxide were shown to be about 0.4% per rad-equivalent, in agreement with the data for radiogenic cancer. The analyses suggest that values of the relative risk coefficients for genotoxic chemicals are independent of species and that relative cancer risks determined in animal tests apply also to humans. If reliable animal test data are not available, cancer risks may be estimated by the relative potency. In both cases exposure dose/target dose relationships, the latter via macromolecule adducts, should be determined.

  15. Exposure Estimation and Interpretation of Occupational Risk: Enhanced Information for the Occupational Risk Manager

    PubMed Central

    Waters, Martha; McKernan, Lauralynn; Maier, Andrew; Jayjock, Michael; Schaeffer, Val; Brosseau, Lisa

    2015-01-01

    The fundamental goal of this article is to describe, define, and analyze the components of the risk characterization process for occupational exposures. Current methods are described for the probabilistic characterization of exposure, including newer techniques that have increasing applications for assessing data from occupational exposure scenarios. In addition, since the probability of health effects reflects variability in the exposure estimate as well as the dose-response curve—the integrated considerations of variability surrounding both components of the risk characterization provide greater information to the occupational hygienist. Probabilistic tools provide a more informed view of exposure as compared to use of discrete point estimates for these inputs to the risk characterization process. Active use of such tools for exposure and risk assessment will lead to a scientifically supported worker health protection program. Understanding the bases for an occupational risk assessment, focusing on important sources of variability and uncertainty enables characterizing occupational risk in terms of a probability, rather than a binary decision of acceptable risk or unacceptable risk. A critical review of existing methods highlights several conclusions: (1) exposure estimates and the dose-response are impacted by both variability and uncertainty and a well-developed risk characterization reflects and communicates this consideration; (2) occupational risk is probabilistic in nature and most accurately considered as a distribution, not a point estimate; and (3) occupational hygienists have a variety of tools available to incorporate concepts of risk characterization into occupational health and practice. PMID:26302336

  16. Diagnostic medical imaging radiation exposure and risk of development of solid and hematologic malignancy.

    PubMed

    Fabricant, Peter D; Berkes, Marschall B; Dy, Christopher J; Bogner, Eric A

    2012-05-01

    Limiting patients' exposure to ionizing radiation during diagnostic imaging is of concern to patients and clinicians. Large single-dose exposures and cumulative exposures to ionizing radiation have been associated with solid tumors and hematologic malignancy. Although these associations have been a driving force in minimizing patients' exposure, significant risks are found when diagnoses are missed and subsequent treatment is withheld. Therefore, based on epidemiologic data obtained after nuclear and occupational exposures, dose exposure limits have been estimated. A recent collaborative effort between the US Food and Drug Administration and the American College of Radiology has provided information and tools that patients and imaging professionals can use to avoid unnecessary ionizing radiation scans and ensure use of the lowest feasible radiation dose necessary for studies. Further collaboration, research, and development should focus on producing technological advances that minimize individual study exposures and duplicate studies. This article outlines the research used to govern safe radiation doses, defines recent initiatives in decreasing radiation exposure, and provides orthopedic surgeons with techniques that may help decrease radiation exposure in their daily practice.

  17. Methods to Develop Inhalation Cancer Risk Estimates for ...

    EPA Pesticide Factsheets

    This document summarizes the approaches and rationale for the technical and scientific considerations used to derive inhalation cancer risks for emissions of chromium and nickel compounds from electric utility steam generating units. The purpose of this document is to discuss the methods used to develop inhalation cancer risk estimates associated with emissions of chromium and nickel compounds from coal- and oil-fired electric utility steam generating units (EGUs) in support of EPA's recently proposed Air Toxics Rule.

  18. Fetal radiation doses and subsequent risks from X-ray examinations: Should we be concerned?

    PubMed Central

    Chaparian, Ali; Aghabagheri, Mahdi

    2013-01-01

    Background: Pregnant women are sometimes exposed to ionizing radiation in radiology examinations for various reasons. In such cases, the radiation dose to the conceptus and subsequent risks should be estimated. Objective: The purpose of this study was the calculation and presentation of fetal dose and subsequent risks resulted from different X-ray examinations. Materials and Methods: An analytical simulation study was conducted and six common radiographies in different views and three types of special examinations were evaluated. The entrance skin exposure (ESE) was measured using a solid-state dosimeter. A Monte Carlo program was used in order to simulate different views of X-ray examinations and calculate the radiation doses received by the conceptus for every view of each examination. Then the risk of childhood cancer and small head size were calculated for different radiographies. Results: The fetal doses and consequence risks of the small head size and childhood cancer for the radiographs of chest, skull, and sinuses were negligible but the risks of childhood cancer and small head size due to radiographies of abdomen, lumbar spine, and pelvis areas were ponderable. Conclusion: Results of this study can be used for the pregnant women radiographies management. PMID:24639714

  19. Comparative dosimetry of radon in mines and homes. Panel of dosimetric assumptions affecting the application of radon risk estimates, Board on Radiation Effects Research, Commission on Life Sciences, National Research Council

    SciTech Connect

    Not Available

    1991-01-01

    The National Academy study addresses a topic of widespread attention since the discovery in 1984 of a worker found to be contaminated with radon in his home. Scientists have long understood the dangers of exposure to radon and its progeny and have analyzed the effects of exposure of these radionuclides in underground miner populations. However, extensive analyses on effects of radon exposure in the home are only now being performed. This study evaluates available data, describes uncertainties and attempts to translate dosimetric information related mine worker exposure to risk information regarding home radon exposures. The Academy's compilation and evaluation of the data are, as usual, pain-staking and thorough. Their discussions of uncertainties is helpful and careful to describe the boundaries and limitations of their results. The dosimetric model which resulted from their comparative evaluation is clearly presented. Risk assessors concerned about residential exposures to radionuclides will find this study useful.

  20. Estimating Radiation Dose Metrics for Patients Undergoing Tube Current Modulation CT Scans

    NASA Astrophysics Data System (ADS)

    McMillan, Kyle Lorin

    Computed tomography (CT) has long been a powerful tool in the diagnosis of disease, identification of tumors and guidance of interventional procedures. With CT examinations comes the concern of radiation exposure and the associated risks. In order to properly understand those risks on a patient-specific level, organ dose must be quantified for each CT scan. Some of the most widely used organ dose estimates are derived from fixed tube current (FTC) scans of a standard sized idealized patient model. However, in current clinical practice, patient size varies from neonates weighing just a few kg to morbidly obese patients weighing over 200 kg, and nearly all CT exams are performed with tube current modulation (TCM), a scanning technique that adjusts scanner output according to changes in patient attenuation. Methods to account for TCM in CT organ dose estimates have been previously demonstrated, but these methods are limited in scope and/or restricted to idealized TCM profiles that are not based on physical observations and not scanner specific (e.g. don't account for tube limits, scanner-specific effects, etc.). The goal of this work was to develop methods to estimate organ doses to patients undergoing CT scans that take into account both the patient size as well as the effects of TCM. This work started with the development and validation of methods to estimate scanner-specific TCM schemes for any voxelized patient model. An approach was developed to generate estimated TCM schemes that match actual TCM schemes that would have been acquired on the scanner for any patient model. Using this approach, TCM schemes were then generated for a variety of body CT protocols for a set of reference voxelized phantoms for which TCM information does not currently exist. These are whole body patient models representing a variety of sizes, ages and genders that have all radiosensitive organs identified. TCM schemes for these models facilitated Monte Carlo-based estimates of fully

  1. Exposure to UV radiation and risk of Hodgkin lymphoma: a pooled analysis

    PubMed Central

    Glaser, Sally L.; Schupp, Clayton W.; Ekström Smedby, Karin; de Sanjosé, Silvia; Kane, Eleanor; Melbye, Mads; Forétova, Lenka; Maynadié, Marc; Staines, Anthony; Becker, Nikolaus; Nieters, Alexandra; Brennan, Paul; Boffetta, Paolo; Cocco, Pierluigi; Glimelius, Ingrid; Clavel, Jacqueline; Hjalgrim, Henrik; Chang, Ellen T.

    2013-01-01

    Ultraviolet radiation (UVR) exposure has been inversely associated with Hodgkin lymphoma (HL) risk, but only inconsistently, only in a few studies, and without attention to HL heterogeneity. We conducted a pooled analysis of HL risk focusing on type and timing of UVR exposure and on disease subtypes by age, histology, and tumor-cell Epstein-Barr virus (EBV) status. Four case-control studies contributed 1320 HL cases and 6381 controls. We estimated lifetime, adulthood, and childhood UVR exposure and history of sunburn and sunlamp use. We used 2-stage estimation with mixed-effects models and weighted pooled effect estimates by inverse marginal variances. We observed statistically significant inverse associations with HL risk for UVR exposures during childhood and adulthood, sunburn history, and sunlamp use, but we found no significant dose-response relationships. Risks were significant only for EBV-positive HL (pooled odds ratio, 0.56; 95% confidence interval, 0.35 to 0.91 for the highest overall UVR exposure category), with a significant linear trend for overall exposure (P = .03). Pooled relative risk estimates were not heterogeneous across studies. Increased UVR exposure may protect against HL, particularly EBV-positive HL. Plausible mechanisms involving UVR induction of regulatory T cells or the cellular DNA damage response suggest opportunities for new prevention targets. PMID:24016459

  2. Preventing risk and promoting resilience in radiation health.

    PubMed

    Kurth, Margaret H; Linkov, Igor

    2016-10-01

    Because risk assessment is fundamentally deficient in the face of unknown or unforeseeable events and disasters such as occurred in 2011 at the Fukushima Daiichi Nuclear Power Station in Japan, resilience thinking, which focuses on the ability of both natural and human-made systems to prepare for, absorb, and recover from an adverse event and to adapt to new conditions is an important additional consideration in decision making. Radiation contamination is an impediment to most critical functions of a community; resilience planning considers how those critical functions will be maintained in the event that radiation contamination does occur. Therefore, planning should begin with resilience-based thinking and should be complemented with risk assessment-based tools. Integr Environ Assess Manag 2016;12:677-679. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  3. Radiation risk and protection of patients in clinical SPECT/CT.

    PubMed

    Brix, Gunnar; Nekolla, Elke A; Borowski, Markus; Noßke, Dietmar

    2014-05-01

    Clinical studies have demonstrated that hybrid single photon emission computed tomography (SPECT)/CT for various diagnostic issues has an added value as compared to SPECT alone. However, the combined acquisition of functional and anatomical images can substantially increase radiation exposure to patients, in particular when using a hybrid system with diagnostic CT capabilities. It is, therefore, essential to carefully balance the diagnostic needs and radiation protection requirements. To this end, the evidence on health effects induced by ionizing radiation is outlined. In addition, the essential concepts for estimating radiation doses and lifetime attributable cancer risks associated with SPECT/CT examinations are presented taking into account both the new recommendations of the International Commission on Radiological Protection (ICRP) as well as the most recent radiation risk models. Representative values of effective dose and lifetime attributable risk are reported for ten frequently used SPECT radiopharmaceuticals and five fully diagnostic partial-body CT examinations. A diagnostic CT scan acquired as part of a combined SPECT/CT examination contributes considerably to, and for some applications even dominates, the total patient exposure. For the common SPECT and CT examinations considered in this study, the lifetime attributable risk of developing a radiation-related cancer is less than 0.27 %/0.37 % for men/women older than 16 years, respectively, and decreases markedly with increasing age at exposure. Since there is no clinical indication for a SPECT/CT examination unless an emission scan has been indicated, the issue on justification comes down to the question of whether it is necessary to additionally acquire a low-dose CT for attenuation correction and anatomical localization of tracer uptake or even a fully diagnostic CT. In any case, SPECT/CT studies have to be optimized, e.g. by adapting dose reduction measures from state-of-the-art CT practice, and

  4. Temporal distributions of risk for radiation-induced cancers.

    PubMed

    Land, C E

    1987-01-01

    Observations of cancer risk in irradiated human populations over time after exposure suggest that there are at least two, and perhaps more, very different patterns of temporal distribution of risk for radiation-induced cancer. The first, exemplified by bone sarcoma following therapeutic injection of 224Ra and chronic granulocytic leukemia in Japanese A-bomb survivors, is an early, wave-like pulse consisting of an increase in risk followed by a gradual decline back to baseline levels. The second, exemplified by breast cancer following a brief exposure to external gamma ray or X ray, and by lung cancer and stomach cancer in A-bomb survivors, is an increase in relative risk over about 10 years to a value which appears to remain constant over time thereafter. The first pattern suggests that tumor growth kinetics may play a central role in the temporal distribution of risk following exposure, while the second seems more consistent with multi-event models for carcinogenesis, in which radiation or some other cause of early events must be followed by one or more later events whose frequencies depend mainly on attained age. There are, however, other data that appear to conform to neither of the two models just mentioned. Influences of other cancer causes, like tobacco smoking, are potentially serious confounding factors in studies of induction period.

  5. Ionizing radiation risks to Satellite Power Systems (SPS) workers in space

    SciTech Connect

    Not Available

    1980-12-01

    A reference Satellite Power System (SPS) has been designed by NASA and its contractors for the purposes of evaluating the concept and carrying out assessments of the various consequences of development, including those on the health of the space workers. The Department of Energy has responsibility for directing various assessments. Present planning calls for the SPS workers to move from Earth to a low earth orbit (LEO) at an altitude of 500 kilometers; to travel by a transfer ellipse (TE) trajectory to a geosynchronous orbit (GEO) at an altitude of 36,000 kilometers; and to remain in GEO orbit for about 90 percent of the total time aloft. The radiation risks to the health of workers who will construct and maintain solar power satellites in the space environment are studied. The charge to the committee was: (a) to evaluate the radiation environment estimated for the Reference System which could represent a hazard; (b) to assess the possible somatic and genetic radiation hazards; and (c) to estimate the risks to the health of SPS workers due to space radiation exposure, and to make recommendations based on these conclusions. Details are presented. (WHK)

  6. Estimating transport fatality risk from past accident data.

    PubMed

    Evans, Andrew W

    2003-07-01

    This paper examines the statistical properties of estimates of fatal accident rates, mean fatalities per accident, and fatality rates when these estimates are based on past accident data. The statistical properties are illustrated by two long-term transport fatal accident datasets from Great Britain, the principal one for railways and the other for roads, chosen to provide a statistical contrast. In both modes, the accident rates have fallen substantially over the long term. Two statistical estimates of current accident and fatality rates are presented for each dataset, one based only on recent data and the other based on estimates of long-term trends. The trend-based estimate is preferred for train accidents because this makes maximum use of the limited and variable data; the recent data are preferred for road accidents because this avoids unnecessary dependence on modelling the trends. For train accidents, the estimated fatality rate based on past accidents is compared with an estimate produced by the railway industry using a risk model. The statistical estimate is less than half the industry's estimate, and the paper concludes that the statistical estimate is to be preferred.

  7. Technical Evaluation of the NASA Model for Cancer Risk to Astronauts Due to Space Radiation

    NASA Technical Reports Server (NTRS)

    2012-01-01

    At the request of NASA, the National Research Council's (NRC's) Committee for Evaluation of Space Radiation Cancer Risk Model1 reviewed a number of changes that NASA proposes to make to its model for estimating the risk of radiation-induced cancer in astronauts. The NASA model in current use was last updated in 2005, and the proposed model would incorporate recent research directed at improving the quantification and understanding of the health risks posed by the space radiation environment. NASA's proposed model is defined by the 2011 NASA report Space Radiation Cancer Risk Projections and Uncertainties--2010 . The committee's evaluation is based primarily on this source, which is referred to hereafter as the 2011 NASA report, with mention of specific sections or tables. The overall process for estimating cancer risks due to low linear energy transfer (LET) radiation exposure has been fully described in reports by a number of organizations. The approaches described in the reports from all of these expert groups are quite similar. NASA's proposed space radiation cancer risk assessment model calculates, as its main output, age- and gender-specific risk of exposure-induced death (REID) for use in the estimation of mission and astronaut-specific cancer risk. The model also calculates the associated uncertainties in REID. The general approach for estimating risk and uncertainty in the proposed model is broadly similar to that used for the current (2005) NASA model and is based on recommendations by the National Council on Radiation Protection and Measurements. However, NASA's proposed model has significant changes with respect to the following: the integration of new findings and methods into its components by taking into account newer epidemiological data and analyses, new radiobiological data indicating that quality factors differ for leukemia and solid cancers, an improved method for specifying quality factors in terms of radiation track structure concepts as

  8. On the estimation of risk associated with an attenuation prediction

    NASA Technical Reports Server (NTRS)

    Crane, R. K.

    1992-01-01

    Viewgraphs from a presentation on the estimation of risk associated with an attenuation prediction is presented. Topics covered include: link failure - attenuation exceeding a specified threshold for a specified time interval or intervals; risk - the probability of one or more failures during the lifetime of the link or during a specified accounting interval; the problem - modeling the probability of attenuation by rainfall to provide a prediction of the attenuation threshold for a specified risk; and an accounting for the inadequacy of a model or models.

  9. Development of software for estimating clear sky solar radiation in Indonesia

    NASA Astrophysics Data System (ADS)

    Ambarita, H.

    2017-01-01

    Research on solar energy applications in Indonesia has come under scrutiny in recent years. Solar radiation is harvested by solar collector or solar cell and convert the energy into useful energy such as heat and or electricity. In order to provide a better configuration of a solar collector or a solar cell, clear sky radiation should be estimated properly. In this study, an in-house software for estimating clear sky radiation is developed. The governing equations are solved simultaneously. The software is tested in Medan city by performing a solar radiation measurements. For clear sky radiation, the results of the software and measurements ones show a good agreement. However, for the cloudy sky condition it cannot predict the solar radiation. This software can be used to estimate the clear sky radiation in Indonesia.

  10. Risk assessment for the harmful effects of UVB radiation on the immunological resistance to infectious diseases.

    PubMed Central

    Goettsch, W; Garssen, J; Slob, W; de Gruijl, F R; Van Loveren, H

    1998-01-01

    Risk assessment comprises four steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization. In this study, the effects of increased ultraviolet B(UVB, 280-315 nm) radiation on immune functions and the immunological resistance to infectious diseases in rats were analyzed according to this strategy. In a parallelogram approach, nonthreshold mathematical methods were used to estimate the risk for the human population after increased exposure to UVB radiation. These data demonstrate, using a worst-case strategy (sensitive individuals, no adaptation), that exposure for approximately 90 min (local noon) at 40 degrees N in July might lead to 50% suppression of specific T-cell mediated responses to Listeria monocytogenes in humans who were not preexposed to UVB (i.e., not adapted). Additionally, a 5% decrease in the thickness of the ozone layer might shorten this exposure time by approximately 2.5%. These data demonstrate that UVB radiation, at doses relevant to outdoor exposure, may affect the specific cellular immune response to Listeria bacteria in humans. Whether this will also lead to a lowered resistance (i.e.,increased pathogenic load) in humans is not known, although it was demonstrated that UVB-induced immunosuppression in rats was sufficient to increase the pathogenic load. Epidemiology studies are needed to validate and improve estimates for the potential effects of increased UVB exposure on infectious diseases in humans. Images Figure 1 Figure 2 PMID:9435148

  11. Radiobiologic risk estimation from dental radiology. Part II. Cancer incidence and fatality

    SciTech Connect

    Underhill, T.E.; Kimura, K.; Chilvarquer, I.; McDavid, W.D.; Langlais, R.P.; Preece, J.W.; Barnwell, G.

    1988-08-01

    With the use of the measured absorbed doses from part I of this article, the specific radiobiologic risk to the patient from (1) five different panoramic machines with rare-earth screens, (2) a 20-film complete-mouth survey with E-speed film, long round cone, (3) a 20-film complete-mouth survey with E-speed film, long rectangular cone, (4) a 4-film interproximal survey with E-speed film, long round cone, and (5) a 4-film interproximal survey with E-speed film, long rectangular cone, was calculated. The estimated risks are expressed in two ways: the probability of radiation-induced cancer in specific organs per million examinations and the probability of expression of a fatal cancer per million examinations. The highest risks calculated were from the complete-mouth survey with the use of round collimation. The lowest risks calculated were from panoramic radiography and four interproximal radiographs with rectangular collimation.

  12. Variants in activators and downstream targets of ATM, radiation exposure, and contralateral breast cancer risk in the WECARE study.

    PubMed

    Brooks, Jennifer D; Teraoka, Sharon N; Reiner, Anne S; Satagopan, Jaya M; Bernstein, Leslie; Thomas, Duncan C; Capanu, Marinela; Stovall, Marilyn; Smith, Susan A; Wei, Shan; Shore, Roy E; Boice, John D; Lynch, Charles F; Mellemkjaer, Lene; Malone, Kathleen E; Liang, Xiaolin; Haile, Robert W; Concannon, Patrick; Bernstein, Jonine L

    2012-01-01

    Ionizing radiation (IR) is a breast carcinogen that induces DNA double-strand breaks (DSBs), and variation in genes involved in the DNA DSB response has been implicated in radiation-induced breast cancer. The Women's Environmental, Cancer, and Radiation Epidemiology (WECARE) study is a population-based study of cases with contralateral breast cancer (CBC) and matched controls with unilateral breast cancer. The location-specific radiation dose received by the contralateral breast was estimated from radiotherapy records and mathematical models. One hundred fifty-two SNPs in six genes (CHEK2, MRE11A, MDC1, NBN, RAD50, TP53BP1) involved in the DNA DSBs response were genotyped. No variants or haplotypes were associated with CBC risk (649 cases and 1,284 controls) and no variants were found to interact with radiation dose. Carriers of a RAD50 haplotype exposed to ≥1 gray (Gy) had an increased risk of CBC compared with unexposed carriers (Rate ratios [RR] = 4.31 [95% confidence intervals [CI] 1.93-9.62]); with an excess relative risk (ERR) per Gy = 2.13 [95% CI 0.61-5.33]). Although the results of this study were largely null, carriers of a haplotype in RAD50 treated with radiation had a greater CBC risk than unexposed carriers. This suggests that carriers of this haplotype may be susceptible to the DNA-damaging effects of radiation therapy associated with radiation-induced breast cancer.

  13. Aspects of operational radiation protection during dismantling of nuclear facilities relevant for the estimation of internal doses.

    PubMed

    Labarta, T

    2007-01-01

    Operational radiation protection of workers during the dismantling of nuclear facilities is based on the same radiation protection principles as that applied in its exploitation period with the objective of ensuring proper implementation of the as-low-as-reasonably-achievable (ALARA) principle. These principles are: prior determination of the nature and magnitude of radiological risk; classification of workplaces and workers depending on the risks; implementation of control measures; monitoring of zones and working conditions, including, if necessary, individual monitoring. From the experiences and the lessons learned during the dismantling processes carried out in Spain, several important aspects in the practical implementation of these principles that directly influence and ensure an adequate prevention of exposures and the estimation of internal doses are pointed out, with special emphasis on the estimation of internal doses due to transuranic intakes.

  14. Ionizing radiation exposures in treatments of solid neoplasms are not associated with subsequent increased risks of chronic lymphocytic leukemia.

    PubMed

    Radivoyevitch, Tomas; Sachs, Rainer K; Gale, Robert Peter; Smith, Mitchell R; Hill, Brian T

    2016-04-01

    Exposure to ionizing radiation is not thought to cause chronic lymphocytic leukemia (CLL). Challenging this notion are recent data suggesting CLL incidence may be increased by radiation exposure from the atomic bombs (after many decades), uranium mining and nuclear power facility accidents. To assess the effects of therapeutic ionizing radiation for the treatment of solid neoplasms we studied CLL risks in data from the Surveillance, Epidemiology, and End Results (SEER) Program. Specifically, we compared the risks of developing CLL in persons with a 1(st) non-hematologic cancer treated with or without ionizing radiation. We controlled for early detection effects on CLL risk induced by surveillance after 1(st) cancer diagnoses by forming all-time cumulative CLL relative risks (RR). We estimate such CLL RR to be 1.20 (95% confidence interval, 1.17, 1.23) for persons whose 1(st) cancer was not treated with ionizing radiation and 1.00 (0.96, 1.05) for persons whose 1(st) cancer was treated with ionizing radiations. These results imply that diagnosis of a solid neoplasm is associated with an increased risk of developing CLL only in persons whose 1(st) cancer was not treated with radiation therapy.

  15. Microdosimetric-based risk factors for radiation received in space activities during a trip to Mars.

    PubMed

    Zaider, M

    1996-06-01

    A system for evaluating quality factors, Q, based on the microdosimetric distribution of the radiation field of interest has been set up; it makes use of a specific quality function (SQF) to obtain--given microdosimetric spectra--values for Q. The advantages of a system based on lineal energy are well recognized. Furthermore, recent studies have shown that spectra in 1-microm diameter tissue-equivalent spherical volumes reproduce correctly (in the sense of this formalism) measured RBE values, and thus a proportional counter would be usable as a practical instrument for radiation protection. All specific quality functions, q(y), available to date have been calculated from in vitro cellular data. To extend this approach to radiations of interest in space activities we have recently obtained a new function q(y) for in vivo radiogenic neoplasia using data on the Harderian gland of the mouse. These data were obtained for charged particles and energies relevant to space exposures. Furthermore, we introduce a new procedure that allows one to obtain--here with the use of microdosimetric distributions for the Hiroshima-Nagasaki radiation fields--risk factors scaled from the A-bomb survivorship results. We apply these concepts to particles and energies representing the galactic spectrum. We estimate that for a trip to Mars (450 d) the excess lifetime cancer mortality due to galactic cosmic ray (GCR) radiation is 0.037. This is about 50% lower than the risk coefficient obtained with the aid of standard (LET-based) quality factors.

  16. Sensitivity of risk estimates to wildlife bioaccumulation factors in ecological risk assessment

    SciTech Connect

    Karustis, C.G.; Brewer, R.A.

    1995-12-31

    The concept of conservatism in risk assessment is well established. However, overly conservative assumptions may result in risk estimates that incorrectly predict remediation goals. Therefore, realistic assumptions should be applied in risk assessment whenever possible. A sensitivity analysis was performed on conservative (i.e. bioaccumulation factor = 1) and scientifically-derived wildlife bioaccumulation factors (BAFs) utilized to calculate risks during a terrestrial ecological risk assessment (ERA). In the first approach, 100% bioaccumulation of contaminants was assumed to estimate the transfer of contaminants through the terrestrial food chain. In the second approach, scientifically-derived BAFs were selected from the literature. For one of the measurement species selected, total risks calculated during the first approach were higher than those calculated during the second approach by two orders of magnitude. However, potential risks due to individual contaminants were not necessarily higher using the conservative approach. Potential risk due to contaminants with low actual bioaccumulation were exaggerated while potential risks due to contaminants with greater than 100% bioaccumulation were underestimated. Therefore, the use of a default of 100% bioaccumulation (BAF = 1) for all contaminants encountered during an ERA could result in cases where contaminants are incorrectly identified as risk drivers, and the calculation of incorrect ecological risk-based cleanup goals. The authors suggest using site-specific or literature-derived BAFs whenever possible and realistic BAF estimates, based upon factors such as log K{sub ow}, when BAFs are unavailable.

  17. The myth of mean dose as a surrogate for radiation risk?

    NASA Astrophysics Data System (ADS)

    Samei, Ehsan; Li, Xiang; Chen, Baiyu; Reiman, Robert

    2010-04-01

    The current estimations of risk associated with medical imaging procedures rely on assessing the organ dose via direct measurements or simulation. Each organ dose is assumed to be homogeneous, a representative sample or mean of which is weighted by a corresponding tissue weighting factor provided by ICRP publication 103. The weighted values are summed to provide Effective Dose (ED), the most-widely accepted surrogate for population radiation risk. For individual risk estimation, one may employ Effective Risk (ER), which further incorporates gender- and age-specific risk factors. However, both the tissue-weighting factors (as used by ED) and the risk factors (as used by ER) were derived (mostly from the atomic bomb survivor data) under the assumption of a homogeneous dose distribution within each organ. That assumption is significantly violated in most medical imaging procedures. In chest CT, for example, superficial organs (eg, breasts) demonstrate a heterogeneous distribution while organs on the peripheries of the irradiation field (eg, liver) possess a nearly discontinuous dose profile. Projection radiography and mammography involve an even wider range of organ dose heterogeneity spanning up to two orders of magnitude. As such, mean dose or point measured dose values do not reflect the maximum energy deposited per unit volume of the organ, and therefore, effective dose or effective risk, as commonly computed, can misrepresent irradiation risk. In this paper, we report the magnitude of the dose heterogeneity in both CT and projection x-ray imaging, provide an assessment of its impact on irradiation risk, and explore an alternative model-based approach for risk estimation for imaging techniques involving heterogeneous organ dose distributions.

  18. The carcinogenic risks of low-LET and high-LET ionizing radiations

    SciTech Connect

    Fabrikant, J.I. )

    1989-08-01

    New information is available concerning the carcinogenic effects of radiation and the implications for risk assessment and risk management. This information comes from further follow-up of the epidemiological studies of the Japanese atomic bomb survivors, patients irradiated medically for cancer and allied conditions, and workers exposed in various occupations. In the Japanese atomic bomb survivors the carcinogenic risks are estimated to be somewhat higher than previously, due to the reassessment of the atomic-bomb dosimetry, further follow-up with increase in the number of excess cancer deaths, particularly in survivors irradiated early in life, and changes in the methods of analysis to compute the age-specific risks of cancer. Because of the characteristics of the atomic bomb survivor series as regards sample size, age and sex distribution, duration for follow-up, person-years at risk, and type of dosimetry, the mortality experience of the atomic bomb survivors was selected by the UNSCEAR Committee and the BEIR V Committee as the more appropriate basis for projecting risk estimates for the general population. In the atomic bomb survivors, the dose-effect relationship for overall cancer mortality other than leukemia is consistent with linearity below 3 Gy, while the dose-effect relationship for leukemia, excluding chronic lymphatic leukemia, conforms best to a linear-quadratic function. The shape of the dose-incidence curve at low doses still remains uncertain, and the data do not rule out the possible existence of a threshold for an neoplasm. The excess relative risk of mortality from all cancers combined is estimated to be 1.39 per Gy (shielded kerma), which corresponds to an absolute risk of 10.0 excess cancer deaths per 10,000 PYGy; the relative risks is 1.41 at 1 Gy (organ-absorbed dose), and an absolute risk of 13.07 excess cancer deaths per 10,000 PYGy. 19 refs.

  19. Reconstruction of financial networks for robust estimation of systemic risk

    NASA Astrophysics Data System (ADS)

    Mastromatteo, Iacopo; Zarinelli, Elia; Marsili, Matteo

    2012-03-01

    In this paper we estimate the propagation of liquidity shocks through interbank markets when the information about the underlying credit network is incomplete. We show that techniques such as maximum entropy currently used to reconstruct credit networks severely underestimate the risk of contagion by assuming a trivial (fully connected) topology, a type of network structure which can be very different from the one empirically observed. We propose an efficient message-passing algorithm to explore the space of possible network structures and show that a correct estimation of the network degree of connectedness leads to more reliable estimations for systemic risk. Such an algorithm is also able to produce maximally fragile structures, providing a practical upper bound for the risk of contagion when the actual network structure is unknown. We test our algorithm on ensembles of synthetic data encoding some features of real financial networks (sparsity and heterogeneity), finding that more accurate estimations of risk can be achieved. Finally we find that this algorithm can be used to control the amount of information that regulators need to require from banks in order to sufficiently constrain the reconstruction of financial networks.

  20. Estimates of endemic waterborne risks from community-intervention studies.

    PubMed

    Calderon, Rebecca L; Craun, Gunther F

    2006-01-01

    The nature and magnitude of endemic waterborne disease are not well characterized in the United States. Epidemiologic studies of various designs can provide an estimate of the waterborne attributable risk along with other types of information. Community drinking water systems frequently improve their operations and may change drinking water treatment and their major source of water. In the United States, many of these treatment changes are the result of regulations promulgated under the Safe Drinking Water Act. A community-intervention study design takes advantage of these "natural" experiments to assess changes in health risks. In this paper, we review the community-intervention studies that have assessed changes in waterborne gastroenteritis risks among immunocompetent populations in industrialized countries. Published results are available from two studies in Australia, one study in the United Kingdom, and one study in the United States. Preliminary results from two other US studies are also available. Although the current information is limited, the risks reported in these community-intervention studies can help inform the national estimate of endemic waterborne gastroenteritis. Information is provided about endemic waterborne risks for unfiltered surface water sources and a groundwater under the influence of surface water. Community-intervention studies with recommended study modifications should be conducted to better estimate the benefits associated with improved drinking water treatment.

  1. Radiation exposure and uterine artery embolization: current risks and risk reduction.

    PubMed

    Tse, Gary; Spies, James B

    2010-09-01

    Uterine embolization has become accepted into the mainstream of fibroid therapies and now is among the most common interventions for the condition. Because the procedure is based on angiographic techniques, it requires fluoroscopic and angiographic imaging, both dependent on exposure to ionizing radiation. Given the increasing popularity of this procedure, it is important to understand the potential impacts of this exposure on both individual patients and also the population as a whole. This review is intended to summarize the our current knowledge of the potential risks associated with the radiation exposure from procedure and how those risks might be controlled and reduced by adjusting techniques used during the procedure.

  2. Impact of microbial count distributions on human health risk estimates.

    PubMed

    Duarte, A S R; Nauta, M J

    2015-02-16

    Quantitative microbiological risk assessment (QMRA) is influenced by the choice of the probability distribution used to describe pathogen concentrations, as this may eventually have a large effect on the distribution of doses at exposure. When fitting a probability distribution to microbial enumeration data, several factors may have an impact on the accuracy of that fit. Analysis of the best statistical fits of different distributions alone does not provide a clear indication of the impact in terms of risk estimates. Thus, in this study we focus on the impact of fitting microbial distributions on risk estimates, at two different concentration scenarios and at a range of prevalence levels. By using five different parametric distributions, we investigate whether different characteristics of a good fit are crucial for an accurate risk estimate. Among the factors studied are the importance of accounting for the Poisson randomness in counts, the difference between treating "true" zeroes as such or as censored below a limit of quantification (LOQ) and the importance of making the correct assumption about the underlying distribution of concentrations. By running a simulation experiment with zero-inflated Poisson-lognormal distributed data and an existing QMRA model from retail to consumer level, it was possible to assess the difference between expected risk and the risk estimated with using a lognormal, a zero-inflated lognormal, a Poisson-gamma, a zero-inflated Poisson-gamma and a zero-inflated Poisson-lognormal distribution. We show that the impact of the choice of different probability distributions to describe concentrations at retail on risk estimates is dependent both on concentration and prevalence levels. We also show that the use of an LOQ should be done consciously, especially when zero-inflation is not used. In general, zero-inflation does not necessarily improve the absolute risk estimation, but performance of zero-inflated distributions in QMRA tends to be

  3. Neoplastic potential of gastric irradiation. IV. Risk estimates

    SciTech Connect

    Griem, M.L.; Justman, J.; Weiss, L.

    1984-12-01

    No significant tumor increase was found in the initial analysis of patients irradiated for peptic ulcer and followed through 1962. A preliminary study was undertaken 22 years later to estimate the risk of cancer due to gastric irradiation for peptic ulcer disease. A population of 2,049 irradiated patients and 763 medically managed patients has been identified. A relative risk of 3.7 was found for stomach cancer and an initial risk estimate of 5.5 x 10(-6) excess stomach cancers per person rad was calculated. A more complete follow-up is in progress to further elucidate this observation and decrease the ascertainment bias; however, preliminary data are in agreement with the Japanese atomic bomb reports.

  4. Medical radiation exposure and risk of retinoblastoma resulting from new germline RB1 mutation.

    PubMed

    Bunin, Greta R; Felice, Marc A; Davidson, William; Friedman, Debra L; Shields, Carol L; Maidment, Andrew; O'Shea, Michael; Nichols, Kim E; Leahey, Ann; Dunkel, Ira J; Jubran, Rima; Rodriguez-Galindo, Carlos; Schmidt, Mary Lou; Weinstein, Joanna L; Goldman, Stewart; Abramson, David H; Wilson, Matthew W; Gallie, Brenda L; Chan, Helen S L; Shapiro, Michael; Cnaan, Avital; Ganguly, Arupa; Meadows, Anna T

    2011-05-15

    Although ionizing radiation induces germline mutations in animals, human studies of radiation-exposed populations have not detected an effect. We conducted a case-control study of sporadic bilateral retinoblastoma, which results from a new germline RB1 mutation, to investigate gonadal radiation exposure of parents from medical sources before their child's conception. Parents of 206 cases from nine North American institutions and 269 controls participated; fathers of 184 cases and 223 friend and relative controls and mothers of 204 cases and 260 controls provided information in telephone interviews on their medical radiation exposure. Cases provided DNA for RB1 mutation testing. Of common procedures, lower gastrointestinal (GI) series conferred the highest estimated dose to testes and ovaries. Paternal history of lower GI series was associated with increased risk of retinoblastoma in the child [matched odds ratio (OR) = 3.6, 95% confidence interval (CI) = 1.2-11.2, two-sided p = 0.02], as was estimated total testicular dose from all procedures combined (OR for highest dose=3.9, 95% CI = 1.2-14.4, p = 0.02). Maternal history of lower GI series was also associated with increased risk (OR = 7.6, 95% CI = 2.8-20.7, p < 0.001) as was the estimated total dose (OR for highest dose = 3.0, 95% CI = 1.4-7.0, p = 0.005). The RB1 mutation spectrum in cases of exposed parents did not differ from that of other cases. Some animal and human data support our findings of an association of gonadal radiation exposure in men and women with new germline RB1 mutation detectable in their children, although bias, confounding, and/or chance may also explain the results.

  5. Medical radiation exposure and risk of retinoblastoma resulting from new germline RB1 mutation

    PubMed Central

    Bunin, Greta R; Felice, Marc A.; Davidson, William; Friedman, Debra L; Shields, Carol L; Maidment, Andrew; O'Shea, Michael; Nichols, Kim E; Leahey, Ann; Dunkel, Ira J; Jubran, Rima; Rodriguez-Galindo, Carlos; Schmidt, Mary Lou; Weinstein, Joanna L; Goldman, Stewart; Abramson, David H; Wilson, Matthew W; Gallie, Brenda L; Chan, Helen S L; Shapiro, Michael; Cnaan, Avital; Ganguly, Arupa; Meadows, Anna T

    2011-01-01

    Although ionizing radiation induces germline mutations in animals, human studies of radiation-exposed populations have not detected an effect. We conducted a case-control study of sporadic bilateral retinoblastoma, which results from a new germline RB1 mutation, to investigate gonadal radiation exposure of parents from medical sources before their child's conception. Parents of 206 cases from 9 North American institutions and 269 controls participated; fathers of 184 cases and 223 friend and relative controls and mothers of 204 cases and 260 controls provided information in telephone interviews on their medical radiation exposure. Cases provided DNA for RB1 mutation testing. Of common procedures, lower GI series conferred the highest estimated dose to testes and ovaries. Paternal history of lower GI series was associated with increased risk of retinoblastoma in the child (matched odds ratio (OR)=3.6, 95% confidence interval (CI) 1.2, 11.2, 2-sided P=0.02), as was estimated total testicular dose from all procedures combined (OR for highest dose=3.9, 95% CI 1.2, 14.4, P =0.02). Maternal history of lower GI series was also associated with increased risk (OR=7.6, 95% CI 2.8, 20.7, P <0.001) as was estimated total dose (OR for highest dose=3.0, 95% CI 1.4, 7.0, P =0.005). The RB1 mutation spectrum in cases of exposed parents did not differ from that of other cases. Some animal and human data support our findings of an association of gonadal radiation exposure in men and women with new germline RB1 mutation detectable in their children, although bias, confounding, and/or chance may also explain the results. PMID:20648557

  6. Estimates of cosmic radiation exposure on Tunisian passenger aircraft.

    PubMed

    Zarrouk, Neïla; Bennaceur, Raouf

    2008-01-01

    Radiation field produced by cosmic radiations in the earth's atmosphere is very complex and is significantly different from that found in the nuclear industry and other environments at ground level. Aircraft crew and frequent flyers are exposed to high levels of cosmic radiations of galactic and solar origin and to secondary radiation produced in the atmosphere. Following recommendations of the International Commission on Radiological Protection in publication 60, the European Union introduced a revised Basic Safety Standard Directive, which included exposure to natural sources of ionising radiations, including cosmic radiation, as occupational exposure. We computed the dose received by some Tunisian flights, using CARI-6, EPCARD, PCAIRE, and SIEVERT codes. Calculations performed during the year 2007, on mostly regular passenger flights of the Nouvelair Tunisian Company, indicate a mean effective dose rate ranging between 3 and 4 microSv/h. We give the general background and details, focusing on the situation in Tunisia with respect to radiation protection aspects of the cosmic radiation exposure. As far as we know, such a study has not previously been carried out.

  7. Models for the risk of secondary cancers from radiation therapy.

    PubMed

    Dasu, Alexandru; Toma-Dasu, Iuliana

    2017-02-24

    The interest in the induction of secondary tumours following radiotherapy has greatly increased as developments in detecting and treating the primary tumours have improved the life expectancy of cancer patients. However, most of the knowledge on the current levels of risk comes from patients treated many decades ago. As developments of irradiation techniques take place at a much faster pace than the progression of the carcinogenesis process, the earlier results could not be easily extrapolated to modern treatments. Indeed, the patterns of irradiation from historically-used orthovoltage radiotherapy and from contemporary techniques like conformal radiotherapy with megavoltage radiation, intensity modulated radiation therapy with photons or with particles are quite different. Furthermore, the increased interest in individualised treatment options raises the question of evaluating and ranking the different treatment plan options from the point of view of the risk for cancer induction, in parallel with the quantification of other long-term effects. It is therefore inevitable that models for risk assessment will have to be used to complement the knowledge from epidemiological studies and to make predictions for newer forms of treatment for which clinical evidence is not yet available. This work reviews the mathematical models that could be used to predict the risk of secondary cancers from radiotherapy-relevant dose levels, as well as the approaches and factors that have to be taken into account when including these models in the clinical evaluation process. These include the effects of heterogeneous irradiation, secondary particles production, imaging techniques, interpatient variability and other confounding factors.

  8. Radiation risk to low fluences of alpha particles may be greater than we thought.

    PubMed

    Zhou, H; Suzuki, M; Randers-Pehrson, G; Vannais, D; Chen, G; Trosko, J E; Waldren, C A; Hei, T K

    2001-12-04

    Based principally on the cancer incidence found in survivors of the atomic bombs dropped in Hiroshima and Nagasaki, the International Commission on Radiation Protection (ICRP) and the United States National Council on Radiation Protection and Measurements (NCRP) have recommended that estimates of cancer risk for low dose exposure be extrapolated from higher doses by using a linear, no-threshold model. This recommendation is based on the dogma that the DNA of the nucleus is the main target for radiation-induced genotoxicity and, as fewer cells are directly damaged, the deleterious effects of radiation proportionally decline. In this paper, we used a precision microbeam to target an exact fraction (either 100% or < or =20%) of the cells in a confluent population and irradiated their nuclei with exactly one alpha particle each. We found that the frequencies of induced mutations and chromosomal changes in populations where some known fractions of nuclei were hit are consistent with non-hit cells contributing significantly to the response. In fact, irradiation of 10% of a confluent mammalian cell population with a single alpha particle per cell results in a mutant yield similar to that observed when all of the cells in the population are irradiated. This effect was significantly eliminated in cells pretreated with a 1 mM dose of octanol, which inhibits gap junction-mediated intercellular communication, or in cells carrying a dominant negative connexin 43 vector. The data imply that the relevant target for radiation mutagenesis is larger than an individual cell and suggest a need to reconsider the validity of the linear extrapolation in making risk estimates for low dose, high linear-energy-transfer (LET) radiation exposure.

  9. Estimating the Reliability of Electronic Parts in High Radiation Fields

    NASA Technical Reports Server (NTRS)

    Everline, Chester; Clark, Karla; Man, Guy; Rasmussen, Robert; Johnston, Allan; Kohlhase, Charles; Paulos, Todd

    2008-01-01

    Radiation effects on materials and electronic parts constrain the lifetime of flight systems visiting Europa. Understanding mission lifetime limits is critical to the design and planning of such a mission. Therefore, the operational aspects of radiation dose are a mission success issue. To predict and manage mission lifetime in a high radiation environment, system engineers need capable tools to trade radiation design choices against system design and reliability, and science achievements. Conventional tools and approaches provided past missions with conservative designs without the ability to predict their lifetime beyond the baseline mission.This paper describes a more systematic approach to understanding spacecraft design margin, allowing better prediction of spacecraft lifetime. This is possible because of newly available electronic parts radiation effects statistics and an enhanced spacecraft system reliability methodology. This new approach can be used in conjunction with traditional approaches for mission design. This paper describes the fundamentals of the new methodology.

  10. Estimation of myocardial volume at risk from CT angiography

    NASA Astrophysics Data System (ADS)

    Zhu, Liangjia; Gao, Yi; Mohan, Vandana; Stillman, Arthur; Faber, Tracy; Tannenbaum, Allen

    2011-03-01

    The determination of myocardial volume at risk distal to coronary stenosis provides important information for prognosis and treatment of coronary artery disease. In this paper, we present a novel computational framework for estimating the myocardial volume at risk in computed tomography angiography (CTA) imagery. Initially, epicardial and endocardial surfaces, and coronary arteries are extracted using an active contour method. Then, the extracted coronary arteries are projected onto the epicardial surface, and each point on this surface is associated with its closest coronary artery using the geodesic distance measurement. The likely myocardial region at risk on the epicardial surface caused by a stenosis is approximated by the region in which all its inner points are associated with the sub-branches distal to the stenosis on the coronary artery tree. Finally, the likely myocardial volume at risk is approximated by the volume in between the region at risk on the epicardial surface and its projection on the endocardial surface, which is expected to yield computational savings over risk volume estimation using the entire image volume. Furthermore, we expect increased accuracy since, as compared to prior work using the Euclidean distance, we employ the geodesic distance in this work. The experimental results demonstrate the effectiveness of the proposed approach on pig heart CTA datasets.

  11. Identifying the health risks from very low-dose sparsely ionizing radiation.

    PubMed Central

    Dreyer, N A; Friedlander, E

    1982-01-01

    The health risks from low-dose sparsely ionizing (low-LET) radiation have been the subject of continued debate. At present, quantitative estimates of risk are extremely uncertain due to the controversy surrounding both the dosimetry for A-bomb survivor data and the choice of mathematical models for extrapolating risk from high to low doses. Nevertheless, much can be learned about the nature of the health risks by reviewing the epidemiologic literature. We present a summary of diseases which have been associated with low-LET radiation (less than 1000 rad) in at least two independent studies, according to the mean cumulative organ dose at which the disease was observed. At organ doses of less than or equal to 50 rad, the only diseases that have been reported consistently are thyroid cancer, salivary gland tumors, and leukemia. The first two diseases were observed in association with x-ray epilation of the scalp for tinea capitis, a therapy which is no longer employed. On the other hand, leukemia has been observed repeatedly to occur at cumulative doses of greater than or equal to 30 rad low-LET radiation. PMID:7041660

  12. [Solar radiation exposure in agriculture: an underestimated risk].

    PubMed

    Gobba, F

    2012-01-01

    Solar Radiation (SR) is a major occupational risk in agriculture, mainly related to its ultraviolet (UV) component. Available data show that UV occupational limits are frequently exceeded in these workers, resulting in an increased occupational risk of various acute and chronic effects, mainly to skin and to the eye. One of the foremost is the carcinogenic effect: SR is indeed included in Group 1 IARC (carcinogenic to humans). UV exposure is related to an increase of the incidence of basal cell carcinoma and squamous cell carcinoma of the skin, and cutaneous malignant melanoma (CMM). The incidence of these tumors, especially CMM, is constantly increasing in Caucasians in the last 50 years. As a conclusion, an adequate evaluation of the occupational risk related to SR, and adequate preventive measures are essential in agriculture. The role of the Occupational Physician in prevention is fundamental.

  13. Estimating Non-stationary Flood Risk in a Changing Climate

    NASA Astrophysics Data System (ADS)

    Yu, X.; Cohn, T. A.; Stedinger, J. R.

    2015-12-01

    Flood risk is usually described by a probability distribution for annual maximum streamflow which is assumed not to change with time. Federal, state and local governments in the United States are demanding guidance on flood frequency estimates that account for climate change. If a trend exists in peak flow series, ignoring it could result in large quantile estimator bias, while trying to estimate a trend will increase the flood quantile estimator's variance. Thus the issue is, what bias-variance tradeoff should we accept? This paper discusses approaches to flood frequency analysis (FFA) when flood series have trends. GCMs describe how annual runoff might vary over sub-continental scales, but this information is nearly useless for FFA in small watersheds. A LP3 Monte Carlo analysis and a re-sampling study of 100-year flood estimation (25- and 50-year projections) compares the performance of five methods: FFA as prescribed in national guidelines (Bulletin 17B), assumes the flood series is stationary and follows a log-Pearson type III (LP3) distribution; Fitting a LP3 distribution with time-varying parameters that include future trends in mean and perhaps variance, where slopes are assumed known; Fitting a LP3 distribution with time-varying parameters that capture future trends in mean and perhaps variance, where slopes are estimated from annual peak flow series; Employing only the most recent 30 years of flood records to fit a LP3 distribution; Applying a safety factor to the 100-year flood estimator (e.g. 25% increase). The 100-year flood estimator of method 2 has the smallest log-space mean squared error, though it is unlikely that the true trend would be known. Method 3 is only recommended over method 1 for large trends (≥ 0.5% per year). The 100-year flood estimators of method 1, 4, and 5 often have poor accuracy. Clearly, flood risk assessment will be a challenge in an uncertain world.

  14. Risk assessment in diabetes management: how do general practitioners estimate risks due to diabetes?

    PubMed Central

    Häussler, Bertram; Fischer, Gisela C; Meyer, Sibylle; Sturm, Diethard

    2007-01-01

    Objectives To evaluate the ability of general practitioners (GPs) in Germany to estimate the risk of patients with diabetes developing complications. Methods An interview study using a structured questionnaire to estimate risks of four case vignettes having diabetes‐specific complications within the next 10 years, risk reduction and life expectancy potential. A representative random sample of 584 GPs has been drawn, of which 150 could be interviewed. We compared GPs' estimates among each other (intraclass correlation coefficient (ICC) and Cohen's (multirater‐) κ) and with risks for long‐term complications generated by the multifactor disease model “Mellibase”, which is a knowledge‐based support system for medical decision management. Results The risk estimates by GPs varied widely (ICC 0.21 95% CI (0.13 to 0.36)). The average level of potential risk reduction was between 47% and 70%. Compared with Mellibase values, on average, the GPs overestimated the risk threefold. Mean estimates of potential prolongation of life expectancy were close to 10 years for each patient, whereas the Mellibase calculations ranged from 3 to 10 years. Conclusions Overestimation could lead to unnecessary care and waste of resources. PMID:17545348

  15. Monte Carlo mixture model of lifetime cancer incidence risk from radiation exposure on shuttle and international space station

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.; Cucinotta, F. A.; Wilson, J. W. (Principal Investigator)

    1999-01-01

    Estimating uncertainty in lifetime cancer risk for human exposure to space radiation is a unique challenge. Conventional risk assessment with low-linear-energy-transfer (LET)-based risk from Japanese atomic bomb survivor studies may be inappropriate for relativistic protons and nuclei in space due to track structure effects. This paper develops a Monte Carlo mixture model (MCMM) for transferring additive, National Institutes of Health multiplicative, and multiplicative excess cancer incidence risks based on Japanese atomic bomb survivor data to determine excess incidence risk for various US astronaut exposure profiles. The MCMM serves as an anchor point for future risk projection methods involving biophysical models of DNA damage from space radiation. Lifetime incidence risks of radiation-induced cancer for the MCMM based on low-LET Japanese data for nonleukemia (all cancers except leukemia) were 2.77 (90% confidence limit, 0.75-11.34) for males exposed to 1 Sv at age 45 and 2.20 (90% confidence limit, 0.59-10.12) for males exposed at age 55. For females, mixture model risks for nonleukemia exposed separately to 1 Sv at ages of 45 and 55 were 2.98 (90% confidence limit, 0.90-11.70) and 2.44 (90% confidence limit, 0.70-10.30), respectively. Risks for high-LET 200 MeV protons (LET=0.45 keV/micrometer), 1 MeV alpha-particles (LET=100 keV/micrometer), and 600 MeV iron particles (LET=180 keV/micrometer) were scored on a per particle basis by determining the particle fluence required for an average of one particle per cell nucleus of area 100 micrometer(2). Lifetime risk per proton was 2.68x10(-2)% (90% confidence limit, 0.79x10(-3)%-0. 514x10(-2)%). For alpha-particles, lifetime risk was 14.2% (90% confidence limit, 2.5%-31.2%). Conversely, lifetime risk per iron particle was 23.7% (90% confidence limit, 4.5%-53.0%). Uncertainty in the DDREF for high-LET particles may be less than that for low-LET radiation because typically there is very little dose-rate dependence

  16. Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

    SciTech Connect

    Baldini, Elizabeth H.; Abrams, Ross A.; Bosch, Walter; Roberge, David; Haas, Rick L.M.; Catton, Charles N.; Indelicato, Daniel J.; Olsen, Jeffrey R.; Deville, Curtiland; Chen, Yen-Lin; Finkelstein, Steven E.; DeLaney, Thomas F.; Wang, Dian

    2015-08-01

    Purpose: The purpose of this study was to evaluate the variability in target volume and organ at risk (OAR) contour delineation for retroperitoneal sarcoma (RPS) among 12 sarcoma radiation oncologists. Methods and Materials: Radiation planning computed tomography (CT) scans for 2 cases of RPS were distributed among 12 sarcoma radiation oncologists with instructions for contouring gross tumor volume (GTV), clinical target volume (CTV), high-risk CTV (HR CTV: area judged to be at high risk of resulting in positive margins after resection), and OARs: bowel bag, small bowel, colon, stomach, and duodenum. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: Ten radiation oncologists contoured both RPS cases, 1 contoured only RPS1, and 1 contoured only RPS2 such that each case was contoured by 11 radiation oncologists. The first case (RPS 1) was a patient with a de-differentiated (DD) liposarcoma (LPS) with a predominant well-differentiated (WD) component, and the second case (RPS 2) was a patient with DD LPS made up almost entirely of a DD component. Contouring agreement for GTV and CTV contours was high. However, the agreement for HR CTVs was only moderate. For OARs, agreement for stomach, bowel bag, small bowel, and colon was high, but agreement for duodenum (distorted by tumor in one of these cases) was fair to moderate. Conclusions: For preoperative treatment of RPS, sarcoma radiation oncologists contoured GTV, CTV, and most OARs with a high level of agreement. HR CTV contours were more variable. Further clarification of this volume with the help of sarcoma surgical oncologists is necessary to reach consensus. More attention to delineation of the duodenum is also needed.

  17. Legitimating a nuclear critic: John Gofman, radiation safety, and cancer risks.

    PubMed

    Semendeferi, Ioanna

    2008-01-01

    Whether low-level ionizing radiation has an effect on humans has been a polarizing issue for the last fifty years. The epicenter of this controversy has been the validity of the linear non-threshold dose-response model, according to which any amount of radiation, however small, causes damage to human genes and health. In the late 1960s and early 1970s, the nuclear scientist and medical researcher John Gofman (1918-2007) played a pivotal role in the debate. Historical accounts have treated Gofman as a radical antinuclear scientist whose unscientific arguments put enormous political pressure on the nuclear power industry and regulatory agencies. Gofman's bitter struggle with the Atomic Energy Commission, which funded his research at Lawrence Livermore National Laboratory, partly accounts for this view. However, my analysis of Gofman's involvement in the low-level radiation debate shows how he also helped shift the focus in radiation safety from the risks of genetic damage or leukemia to somatic or cancer risks. His arguments led to the introduction of the linear non-threshold radiation model as a means of numerically estimating cancer risks. This was a watershed event in radiation-safety science and politics. Gofman's case sheds light on the process by which a scientist could secure legitimation even when his technical arguments threatened the government's interests. I conclude that it also points to an open issue in the history of antinuclear scientists, or of other politically active scientists or technology critics: treating them as critics should not preclude historians from treating them as scientists.

  18. Cellular and molecular research to reduce uncertainties in estimates of health effects from low-level radiation

    SciTech Connect

    Elkind, M.M.; Bedford, J.; Benjamin, S.A.; Waldren, C.A. ); Gotchy, R.L. )

    1990-10-01

    A study was undertaken by five radiation scientists to examine the feasibility of reducing the uncertainties in the estimation of risk due to protracted low doses of ionizing radiation. In addressing the question of feasibility, a review was made by the study group: of the cellular, molecular, and mammalian radiation data that are available; of the way in which altered oncogene properties could be involved in the loss of growth control that culminates in tumorigenesis; and of the progress that had been made in the genetic characterizations of several human and animal neoplasms. On the basis of this analysis, the study group concluded that, at the present time, it is feasible to mount a program of radiation research directed at the mechanism(s) of radiation-induced cancer with special reference to risk of neoplasia due to protracted, low doses of sparsely ionizing radiation. To implement a program of research, a review was made of the methods, techniques, and instruments that would be needed. This review was followed by a survey of the laboratories and institutions where scientific personnel and facilities are known to be available. A research agenda of the principal and broad objectives of the program is also discussed. 489 refs., 21 figs., 14 tabs.

  19. Cumulative radiation exposure from imaging procedures and associated lifetime cancer risk for patients with lymphoma

    PubMed Central

    Fabritius, Grete; Brix, Gunnar; Nekolla, Elke; Klein, Stefan; Popp, Henning D.; Meyer, Mathias; Glatting, Gerhard; Hagelstein, Claudia; Hofmann, Wolf K.; Schoenberg, Stefan O.; Henzler, Thomas

    2016-01-01

    The aim of this study was to systematically evaluate the cumulative radiation exposure and the associated lifetime-cancer-risk from diagnostic imaging in patients with Hodgkin-lymphoma-(HL) or diffuse-large-B-cell-lymphoma (DLBCL). 99 consecutive patients (53-males) diagnosed with HL or DLBCL were included in the study and followed. Based on the imaging reports, organ and effective-doses-(ED) were calculated individually for each patient and the excess lifetime risks were estimated. The average ED in the first year after diagnosis was significantly different for men (59 ± 33 mSv) and women (744 ± 33 mSv)-(p < 0.05). The mean cumulative ED in each of the following 5 years was 16 ± 16 mSv without significant differences between men and women-(p > 0.05). Over all years, more than 90% of the ED resulted from CT. The average cumulative radiation risk estimated for the first year was significantly lower for men (0.76 ± 0.41%) as compared to women (1.28 ± 0.54%)-(p < 0.05). The same was found for each of the subsequent 5-years (men-0.18 ± 0.17%; women-0.28 ± 0.25%)-(p < 0.05). In conclusion, for HL and DLBCL patients investigated in this study, a cumulative radiation risk of about 1 excess cancer per 100 patients is estimated for diagnostic imaging procedures performed during both the first year after diagnosis and a follow-up period of 5 years. PMID:27748377

  20. Radiation efficacy and biological risk from whole-breast irradiation via intensity modulated radiation therapy (IMRT)

    NASA Astrophysics Data System (ADS)

    Desantis, David M.

    Radiotherapy is an established modality for women with breast cancer. During the delivery of external beam radiation to the breast, leakage, scattered x-rays from the patient and the linear accelerator also expose healthy tissues and organs outside of the breast, thereby increasing the patient's whole-body dose, which then increases the chance of developing a secondary, radiation-induced cancer. Generally, there are three IntensityModulated Radiotherapy (IMRT) delivery techniques from a conventional linear accelerator; forward planned (FMLC), inverse planned 'sliding window' (DMLC), and inverse planned 'step-and-shoot' (SMLC). The goal of this study was to determine which of these three techniques delivers an optimal dose to the breast with the least chance of causing a fatal, secondary, radiation-induced cancer. A conventional, non-IMRT, 'Wedge' plan also was compared. Computerized Tomography (CT) data sets for both a large and small sized patient were used in this study. With Varian's Eclipse AAA algorithm, the organ doses specified in the revised ICRP 60 publication were used to calculate the whole-body dose. Also, an anthropomorphic phantom was irradiated with thermoluminescent dosimeters (TLD) at each organ site for measured doses. The risk coefficient from the Biological Effects of Ionizing Radiation (BEIR) VII report of 4.69 x 10-2 deaths per Gy was used to convert whole-body dose to risk of a fatal, secondary, radiation-induced cancer. The FMLC IMRT delivered superior tumor coverage over the 3D conventional plan and the inverse DMLC or SMLC treatment plans delivered clinically equivalent tumor coverage. However, the FMLC plan had the least likelihood of inadvertently causing a fatal, secondary, radiation-induced cancer compared to the inverse DMLC, SMLC, and Wedge plans.

  1. [Mobile phones radiate--risk to the health?].

    PubMed

    Jokela, Kari; Auvinen, Anssi; Hämäläinen, Heikki

    2011-01-01

    The mobile phones radiate electromagnetic energy which is partly absorbed into the tissues in the vicinity of the phone. The minor heating, in maximum up to 0.3 degrees C, may cause some alterations in the expression of genes and proteins similar to physiological response to other stimuli. Biophysical studies at the cellular and molecular level have not revealed any well established interaction mechanism, through which mobile phone radiation could induce toxic effects below the thermal effect level. Research results on various biological effects in vitro and in vivo are continuously published but there is no consistent evidence on well established harmful effects. The mobile phone radiation is not carcinogenic for experimental animals or genotoxic for cells. According to epidemiological studies and psychophysiological brain function studies the use of mobile phones does not seem to increase the risk of tumors in the head and brain or disturb the function of central nervous system. However, there is a need for more research on the long-term effects of mobile phone radiation particularly on children.

  2. Acute Radiation Risk and BRYNTRN Organ Dose Projection Graphical User Interface

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Hu, Shaowen; Nounu, Hateni N.; Kim, Myung-Hee

    2011-01-01

    The integration of human space applications risk projection models of organ dose and acute radiation risk has been a key problem. NASA has developed an organ dose projection model using the BRYNTRN with SUM DOSE computer codes, and a probabilistic model of Acute Radiation Risk (ARR). The codes BRYNTRN and SUM DOSE are a Baryon transport code and an output data processing code, respectively. The risk projection models of organ doses and ARR take the output from BRYNTRN as an input to their calculations. With a graphical user interface (GUI) to handle input and output for BRYNTRN, the response models can be connected easily and correctly to BRYNTRN. A GUI for the ARR and BRYNTRN Organ Dose (ARRBOD) projection code provides seamless integration of input and output manipulations, which are required for operations of the ARRBOD modules. The ARRBOD GUI is intended for mission planners, radiation shield designers, space operations in the mission operations directorate (MOD), and space biophysics researchers. BRYNTRN code operation requires extensive input preparation. Only a graphical user interface (GUI) can handle input and output for BRYNTRN to the response models easily and correctly. The purpose of the GUI development for ARRBOD is to provide seamless integration of input and output manipulations for the operations of projection modules (BRYNTRN, SLMDOSE, and the ARR probabilistic response model) in assessing the acute risk and the organ doses of significant Solar Particle Events (SPEs). The assessment of astronauts radiation risk from SPE is in support of mission design and operational planning to manage radiation risks in future space missions. The ARRBOD GUI can identify the proper shielding solutions using the gender-specific organ dose assessments in order to avoid ARR symptoms, and to stay within the current NASA short-term dose limits. The quantified evaluation of ARR severities based on any given shielding configuration and a specified EVA or other mission

  3. Radiative energy budget estimates for the 1979 southwest summer monsoon

    NASA Technical Reports Server (NTRS)

    Ackerman, Steven A.; Cox, Stephen K.

    1987-01-01

    A major objective of the summer monsoon experiment (SMONEX) was the determination of the heat sources and sinks associated with the southwest summer monsoon. The radiative component is presented here. The vertically integrated tropospheric radiation energy budget is negative and varies significantly as a function of monsoon activity. The gradient in the latitudinal mean tropospheric cooling reverses between the winter periods and the late spring/early summer periods. The radiative component of the vertical profile of the diabatic heating is derived. These profiles are a strong function of the stage of the monsoon as well as the geographic region. In general, the surface experiences a net gain of radiative energy during the late spring and early summer periods. During the winter periods, areas northward of 25 N display net surface losses, while the remaining areas exhibit net gains.

  4. Biodosimetry as a New Paradigm for Determination of Radiation Risks and Risk-Mitigation in Astronauts Exposed to Space Radiation

    NASA Technical Reports Server (NTRS)

    Richmond, Robert; Cruz, Angela; Bors, Karen

    2004-01-01

    Predicting risk of cancer in astronauts exposed to space radiation is challenging partly because uncertainties of absorption of dose and the processing of dose-related damage at the cellular level degrade the confidence of predicting the expression of cancer. Cellular biodosimeters that simultaneously report: 1) the quantity of absorbed dose after exposure to ionizing radiation, 2) the quality of radiation delivering that dose, and 3) the macromolecular profiles related to malignant transformation in cells absorbing that dose would therefore be useful. An approach to such a multiparametric biodosimeter will be reported, This is the demonstration of two dose-responsive field-effects of enhanced protein-expression. In one case, expression of keratin 18 (K18) in cultures of human mammary epithelial cells (HMEC) irradiated with cesium-137 gamma-rays is enhanced following exposure of log phase cells to relatively low doses of 30 to 90 cGy. K18 has been reported by a marker for tumor staging and for apoptosis. In the second case, expression of connexin 43 (Cx43) is increased in irradiated stationary phase cultures of HMEC, indicating enhanced formation of gap junctions. Gap junctions have been reported to be involved in bystander effects following irradiation. It is a biodosimeter for assessing radiogenic damage. It is suggested further that such biomolecular dosimetry may introduce a new paradigm for assessing cancer risk and risk-mitigation in individuals, a requirement for managing radiation health in astronauts during extended missions in space. This new paradigm is built upon the statistical power provided by the use of functional genomics and proteomics represented in combined gene- and protein-expression assays.

  5. Attributable Risk Estimate of Severe Psoriasis on Major Cardiovascular Events

    PubMed Central

    Mehta, Nehal N.; Yu, YiDing; Pinnelas, Rebecca; Krishnamoorthy, Parasuram; Shin, Daniel B.; Troxel, Andrea B.; Gelfand, Joel M.

    2011-01-01

    Background Recent studies suggest that psoriasis, particularly if severe, may be a risk factor for major adverse cardiac events such as myocardial infarction, stroke, and mortality from cardiovascular disease. We compared the risk of major adverse cardiac events between patients with psoriasis and the general population and estimated the attributable risk of severe psoriasis. Methods We performed a cohort study in the General Practice Research Database. Severe psoriasis was defined as receiving a psoriasis diagnosis and systemic therapy (N=3,603). Up to 4 patients without psoriasis were selected from the same practices and start dates for each patient with psoriasis (N=14,330). Results Severe psoriasis was a risk factor for major adverse cardiac events (hazard ratio 1.53; 95% confidence interval 1.26, 1.85) after adjusting for age, gender, diabetes, hypertension, tobacco use and hyperlipidemia. After fully adjusted analysis, severe psoriasis conferred an additional 6.2% absolute risk of 10-year major adverse cardiac events. Conclusions Severe psoriasis confers an additional 6.2% absolute risk of 10-year rate of major adverse cardiac events compared to the general population. This potentially has important therapeutic implications for cardiovascular risk stratification and prevention in patients with severe psoriasis. Future prospective studies are needed to validate these findings. PMID:21787906

  6. Estimation of earthquake risk curves of physical building damage

    NASA Astrophysics Data System (ADS)

    Raschke, Mathias; Janouschkowetz, Silke; Fischer, Thomas; Simon, Christian

    2014-05-01

    In this study, a new approach to quantify seismic risks is presented. Here, the earthquake risk curves for the number of buildings with a defined physical damage state are estimated for South Africa. Therein, we define the physical damage states according to the current European macro-seismic intensity scale (EMS-98). The advantage of such kind of risk curve is that its plausibility can be checked more easily than for other types. The earthquake risk curve for physical building damage can be compared with historical damage and their corresponding empirical return periods. The number of damaged buildings from historical events is generally explored and documented in more detail than the corresponding monetary losses. The latter are also influenced by different economic conditions, such as inflation and price hikes. Further on, the monetary risk curve can be derived from the developed risk curve of physical building damage. The earthquake risk curve can also be used for the validation of underlying sub-models such as the hazard and vulnerability modules.

  7. Estimating risks of heat strain by age and sex: a population-level simulation model.

    PubMed

    Glass, Kathryn; Tait, Peter W; Hanna, Elizabeth G; Dear, Keith

    2015-05-18

    Individuals living in hot climates face health risks from hyperthermia due to excessive heat. Heat strain is influenced by weather exposure and by individual characteristics such as age, sex, body size, and occupation. To explore the population-level drivers of heat strain, we developed a simulation model that scales up individual risks of heat storage (estimated using Myrup and Morgan's man model "MANMO") to a large population. Using Australian weather data, we identify high-risk weather conditions together with individual characteristics that increase the risk of heat stress under these conditions. The model identifies elevated risks in children and the elderly, with females aged 75 and older those most likely to experience heat strain. Risk of heat strain in males does not increase as rapidly with age, but is greatest on hot days with high solar radiation. Although cloudy days are less dangerous for the wider population, older women still have an elevated risk of heat strain on hot cloudy days or when indoors during high temperatures. Simulation models provide a valuable method for exploring population level risks of heat strain, and a tool for evaluating public health and other government policy interventions.

  8. Ionizing radiation exposure of LDEF (pre-recovery estimates)

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Heinrich, W.; Parnell, T. A.; Armstrong, T. W.; Derrickson, J. H.; Fishman, G. J.; Frank, A. L.; Watts, J. W. Jr; Wiegel, B.

    1992-01-01

    The long duration exposure facility (LDEF), launched into a 258 nautical mile orbit with an inclination of 28.5 degrees, remained in space for nearly 6 yr. The 21,500 lb NASA satellite was one of the largest payloads ever deployed by the Space Shuttle. LDEF completed 32,422 orbits and carried 57 major experiments representing more than 200 investigators from 33 private companies, 21 universities and nine countries. The experiments covered a wide range of disciplines including basic science, electronics, optics, materials, structures and power and propulsion. A number of the experiments were specifically designed to measure the radiation environment. These experiments are of specific interest, since the LDEF orbit is essentially the same as that of the Space Station Freedom. Consequently, the radiation measurements on LDEF will play a significant role in the design of radiation shielding of the space station. The contributions of the various authors presented here attempt to predict the major aspects of the radiation exposure received by the various LDEF experiments and therefore should be helpful to investigators who are in the process of analyzing experiments which may have been affected by exposure to ionizing radiation. The paper discusses the various types and sources of ionizing radiation including cosmic rays, trapped particles (both protons and electrons) and secondary particles (including neutrons, spallation products and high-LET recoils), as well as doses and LET spectra as a function of shielding. Projections of the induced radioactivity of LDEF are also discussed.

  9. Radiation exposure and risk assessment for critical female body organs

    SciTech Connect

    Atwell, W.; Weyland, M.D.; Hardy, A.C. NASA, Johnson Space Center, Houston, TX )

    1991-07-01

    Space radiation exposure limits for astronauts are based on recommendations of the National Council on Radiation Protection and Measurements. These limits now include the age at exposure and sex of the astronaut. A recently-developed computerized anatomical female (CAF) model is discussed in detail. Computer-generated, cross-sectional data are presented to illustrate the completeness of the CAF model. By applying ray-tracing techniques, shield distribution functions have been computed to calculate absorbed dose and dose equivalent values for a variety of critical body organs (e.g., breasts, lungs, thyroid gland, etc.) and mission scenarios. Specific risk assessments, i.e., cancer induction and mortality, are reviewed. 13 refs.

  10. A Review of Expertise and Judgment Processes for Risk Estimation

    SciTech Connect

    R. L. Boring

    2007-06-01

    A major challenge of risk and reliability analysis for human errors or hardware failures is the need to enlist expert opinion in areas for which adequate operational data are not available. Experts enlisted in this capacity provide probabilistic estimates of reliability, typically comprised of a measure of central tendency and uncertainty bounds. While formal guidelines for expert elicitation are readily available, they largely fail to provide a theoretical basis for expertise and judgment. This paper reviews expertise and judgment in the context of risk analysis; overviews judgment biases, the role of training, and multivariate judgments; and provides guidance on the appropriate use of atomistic and holistic judgment processes.

  11. Machine detector interface studies: Layout and synchrotron radiation estimate in the future circular collider interaction region

    NASA Astrophysics Data System (ADS)

    Boscolo, Manuela; Burkhardt, Helmut; Sullivan, Michael

    2017-01-01

    The interaction region layout for the e+e- future circular collider FCC-ee is presented together with a preliminary estimate of synchrotron radiation that affects this region. We describe in this paper the main guidelines of this design and the estimate of synchrotron radiation coming from the last bending magnets and from the final focus quadrupoles, with the software tools developed for this purpose. The design follows the asymmetric optics layout as far as incoming bend radiation is concerned with the maximum foreseen beam energy of 175 GeV and we present a feasible initial layout with an indication of tolerable synchrotron radiation.

  12. Estimating Surface Radiation Fluxes in the Arctic from TOVS Brightness Temperatures

    NASA Technical Reports Server (NTRS)

    Schweiger, A. J.; Key, J. R.

    1997-01-01

    A new method for estimating downwelling shortwave and longwave radiation fluxes in the Arctic from TOVS brightness temperatures has been developed. The method employs a neural network to bypass computationally intensive inverse and for-ward radiative transfer calculations, Results from two drifting ice camps (CEAREX, LeadEx) and from one coastal station show that downwelling fluxes can be estimated with r.m.s. errors of 20 W/sq m for longwave radiation and 35 W/sq m for shortwave radiation. Mean errors are less than 4 W/sq m and are well within the bounds required for many climate process studies.

  13. Assessment of Radiation Risk by Circulating microRNAs

    NASA Astrophysics Data System (ADS)

    Wang, Jufang

    2016-07-01

    Highly energized particles delivered by galactic cosmic rays as well as solar particle events are one of the most severe detrimental factors to the health of crews during long-term space missions. Researches related to the assessment of radiation risk have been carried out with ground-based accelerator facilities all around the world. Circulating microRNAs (miRNAs) in blood have the advantages of specificity and stability, which could be used as disease biomarkers and potential bio-dosimeters to monitor the radiation risk. Based on this backgroud, circulating miRNAs were isolated from blood after Kunming mice were whole-body exposed to 300MeV/u carbon ion beam which were generated by the Heavy Ion Research Facility in Lanzhou (HIRFL), and the levels of miRNA expression were detected by miRNA PCR array. It was found that more than one hundred of circulating miRNAs were responded to carbon ion irradiation. Among these radiosensitive miRNAs, most of them were closely associated with immune system and hematopoietic system. The miRNA levels changed more than 2-fold were further verified by qRT-PCR analysis following exposure to X rays and iron ion beam. Some miRNAs such as let-7a, miR-34a, miR-223 and miR-150 showed obvious radio-sensitivity and dose-dependent effect, demonstrating that they were potential biomarkers of radiation and could be used as ideal bio-dosimeters. Those findings indicate that with the properties of high radio-sensitivity and time-saving quantification method by standard PCR assay, circulating miRNAs may become potential biomarkers for radiation detection in space exploration.

  14. Monte Carlo estimation of radiation doses during paediatric barium meal and cystourethrography examinations.

    PubMed

    Dimitriadis, A; Gialousis, G; Makri, T; Karlatira, M; Karaiskos, P; Georgiou, E; Papaodysseas, S; Yakoumakis, E

    2011-01-21

    Organ doses are important quantities in assessing the radiation risk. In the case of children, estimation of this risk is of particular concern due to their significant radiosensitivity and the greater health detriment. The purpose of this study is to estimate the organ doses to paediatric patients undergoing barium meal and micturating cystourethrography examinations by clinical measurements and Monte Carlo simulation. In clinical measurements, dose-area products (DAPs) were assessed during examination of 50 patients undergoing barium meal and 90 patients undergoing cystourethrography examinations, separated equally within three age categories: namely newborn, 1 year and 5 years old. Monte Carlo simulation of photon transport in male and female mathematical phantoms was applied using the MCNP5 code in order to estimate the equivalent organ doses. Regarding the micturating cystourethrography examinations, the organs receiving considerable amounts of radiation doses were the urinary bladder (1.87, 2.43 and 4.7 mSv, the first, second and third value in the parentheses corresponds to neonatal, 1 year old and 5 year old patients, respectively), the large intestines (1.54, 1.8, 3.1 mSv), the small intestines (1.34, 1.56, 2.78 mSv), the stomach (1.46, 1.02, 2.01 mSv) and the gall bladder (1.46, 1.66, 2.18 mSv), depending upon the age of the child. Organs receiving considerable amounts of radiation during barium meal examinations were the stomach (9.81, 9.92, 11.5 mSv), the gall bladder (3.05, 5.74, 7.15 mSv), the rib bones (9.82, 10.1, 11.1 mSv) and the pancreas (5.8, 5.93, 6.65 mSv), depending upon the age of the child. DAPs to organ/effective doses conversion factors were derived for each age and examination in order to be compared with other studies.

  15. Monte Carlo estimation of radiation doses during paediatric barium meal and cystourethrography examinations

    NASA Astrophysics Data System (ADS)

    Dimitriadis, A.; Gialousis, G.; Makri, T.; Karlatira, M.; Karaiskos, P.; Georgiou, E.; Papaodysseas, S.; Yakoumakis, E.

    2011-01-01

    Organ doses are important quantities in assessing the radiation risk. In the case of children, estimation of this risk is of particular concern due to their significant radiosensitivity and the greater health detriment. The purpose of this study is to estimate the organ doses to paediatric patients undergoing barium meal and micturating cystourethrography examinations by clinical measurements and Monte Carlo simulation. In clinical measurements, dose-area products (DAPs) were assessed during examination of 50 patients undergoing barium meal and 90 patients undergoing cystourethrography examinations, separated equally within three age categories: namely newborn, 1 year and 5 years old. Monte Carlo simulation of photon transport in male and female mathematical phantoms was applied using the MCNP5 code in order to estimate the equivalent organ doses. Regarding the micturating cystourethrography examinations, the organs receiving considerable amounts of radiation doses were the urinary bladder (1.87, 2.43 and 4.7 mSv, the first, second and third value in the parentheses corresponds to neonatal, 1 year old and 5 year old patients, respectively), the large intestines (1.54, 1.8, 3.1 mSv), the small intestines (1.34, 1.56, 2.78 mSv), the stomach (1.46, 1.02, 2.01 mSv) and the gall bladder (1.46, 1.66, 2.18 mSv), depending upon the age of the child. Organs receiving considerable amounts of radiation during barium meal examinations were the stomach (9.81, 9.92, 11.5 mSv), the gall bladder (3.05, 5.74, 7.15 mSv), the rib bones (9.82, 10.1, 11.1 mSv) and the pancreas (5.8, 5.93, 6.65 mSv), depending upon the age of the child. DAPs to organ/effective doses conversion factors were derived for each age and examination in order to be compared with other studies.

  16. Radiation Doses and Associated Risk From the Fukushima Nuclear Accident.

    PubMed

    Ishikawa, Tetsuo

    2017-03-01

    The magnitude of dose due to the Fukushima Daiichi Accident was estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2013 report published in April 2014. Following this, the UNSCEAR white paper, which comprises a digest of new information for the 2013 Fukushima report, was published in October 2015. Another comprehensive report on radiation dose due to the accident is the International Atomic Energy Agency (IAEA) report on the Fukushima Daiichi Accident published in August 2015. Although the UNSCEAR and IAEA publications well summarize doses received by residents, they review only literature published before the end of December 2014 and the end of March 2015, respectively. However, some studies on dose estimation have been published since then. In addition, the UNSCEAR 2013 report states it was likely that some overestimation had been introduced generally by the methodology used by the Committee. For example, effects of decontamination were not considered in the lifetime external dose estimated. Decontamination is in progress for most living areas in Fukushima Prefecture, which could reduce long-term external dose to residents. This article mainly reviews recent English language articles that may add new information to the UNSCEAR and IAEA publications. Generally, recent articles suggest lower doses than those presented by the UNSCEAR 2013 report.

  17. What Becomes of Nuclear Risk Assessment in Light of Radiation Hormesis?

    PubMed Central

    Cuttler, Jerry M.

    2007-01-01

    A nuclear probabilistic risk or safety assessment (PRA or PSA) is a scientific calculation that uses assumptions and models to determine the likelihood of plant or fuel repository failures and the corresponding releases of radioactivity. Estimated radiation doses to the surrounding population are linked inappropriately to risks of cancer death and congenital malformations. Even though PRAs use very pessimistic assumptions, they demonstrate that nuclear power plants and fuel repositories are very safe compared with the health risks of other generating options or other risks that people readily accept. Because of the frightening negative images and the exaggerated safety and health concerns that are communicated, many people judge nuclear risks to be unacceptable and do not favour nuclear plants. Large-scale tests and experience with nuclear accidents demonstrate that even severe accidents expose the public to only low doses of radiation, and a century of research has demonstrated that such exposures are beneficial to health. A scientific basis for this phenomenon now exists. PRAs are valuable tools for improving plant designs, but if nuclear power is to play a significant role in meeting future energy needs, we must communicate its many real benefits and dispel the negative images formed by unscientific extrapolations of harmful effects at high doses. PMID:18648610

  18. Demonstration of the Effect of Generic Anatomical Divisions versus Clinical Protocols on Computed Tomography Dose Estimates and Risk Burden

    PubMed Central

    Moorin, Rachael E.; Gibson, David A. J.; Forsyth, Rene K.; Fox, Richard

    2014-01-01

    Objective Choosing to undertake a CT scan relies on balancing risk versus benefit, however risks associated with CT scanning have generally been limited to broad anatomical locations, which do not provided adequate information to evaluate risk against benefit. Our study aimed to determine differences in radiation dose and risk estimates associated with modern CT scanning examinations when computed for clinical protocols compared with those using anatomical area. Methods Technical data were extracted from a tertiary hospital Picture Archiving Communication System for random samples of 20–40 CT examinations per adult clinical CT protocol. Organ and whole body radiation dose were calculated using ImPACT Monte Carlo simulation software and cancer incidence and mortality estimated using BEIR VII age and gender specific lifetime attributable risk weights. Results Thirty four unique CT protocols were identified by our study. When grouped according to anatomic area the radiation dose varied substantially, particularly for abdominal protocols. The total estimated number of incident cancers and cancer related deaths using the mean dose of anatomical area were 86 and 69 respectively. Using more specific protocol doses the estimates rose to 214 and 138 incident cancers and cancer related deaths, at least doubling the burden estimated. Conclusions Modern CT scanning produces a greater diversity of effective doses than much of the literature describes; where a lack of focus on actual scanning protocols has produced estimates that do not reflect the range and complexity of modern CT practice. To allow clinicians, patients and policy makers to make informed risk versus benefit decisions the individual and population level risks associated with modern CT practices are essential. PMID:24878841

  19. Risk assessment and late effects of radiation in low-earth orbits

    SciTech Connect

    Fry, R.J.M.

    1989-01-01

    The radiation dose rates in low-earth orbits are dependent on the altitude and orbital inclination. The doses to which the crews of space vehicles are exposed is governed by the duration of the mission and the shielding, and in low-earth orbit missions protons are the dominant particles encountered. The risk of concern with the low dose rates and the relatively low total doses of radiation that will be incurred on the space station is excess cancer. The National Council on Radiation Protection and Measurements has recently recommended career dose-equivalent limits that take into account sex and age. The new recommendations for career limits range from 1.0 Sv to 4 Sv, depending on sex and on the age at the time of their first space mission, compared to a single career limit of 4.0 Sv previously used by NASA. Risk estimates for radiated-induced cancer are evolving and changes in the current guidance may be required in the next few years. 10 refs., 1 fig., 3 tabs.

  20. Risk assessment and management of radiofrequency radiation exposure

    NASA Astrophysics Data System (ADS)

    Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

    2013-11-01

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

  1. Risk assessment and management of radiofrequency radiation exposure

    SciTech Connect

    Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

    2013-11-13

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

  2. Radiation-Induced Rib Fractures After Hypofractionated Stereotactic Body Radiation Therapy: Risk Factors and Dose-Volume Relationship

    SciTech Connect

    Asai, Kaori; Shioyama, Yoshiyuki; Nakamura, Katsumasa; Sasaki, Tomonari; Ohga, Saiji; Nonoshita, Takeshi; Yoshitake, Tadamasa; Ohnishi, Kayoko; Terashima, Kotaro; Matsumoto, Keiji; Hirata, Hideki; Honda, Hiroshi

    2012-11-01

    Purpose: The purpose of this study was to clarify the incidence, the clinical risk factors, and the dose-volume relationship of radiation-induced rib fracture (RIRF) after hypofractionated stereotactic body radiation therapy (SBRT). Methods and Materials: One hundred sixteen patients treated with SBRT for primary or metastatic lung cancer at our institution, with at least 6 months of follow-up and no previous overlapping radiation exposure, were included in this study. To determine the clinical risk factors associated with RIRF, correlations between the incidence of RIRF and the variables, including age, sex, diagnosis, gross tumor volume diameter, rib-tumor distance, and use of steroid administration, were analyzed. Dose-volume histogram analysis was also conducted. Regarding the maximum dose, V10, V20, V30, and V40 of the rib, and the incidences of RIRF were compared between the two groups divided by the cutoff value determined by the receiver operating characteristic curves. Results: One hundred sixteen patients and 374 ribs met the inclusion criteria. Among the 116 patients, 28 patients (46 ribs) experienced RIRF. The estimated incidence of rib fracture was 37.7% at 3 years. Limited distance from the rib to the tumor (<2.0 cm) was the only significant risk factor for RIRF (p = 0.0001). Among the dosimetric parameters used for receiver operating characteristic analysis, the maximum dose showed the highest area under the curve. The 3-year estimated risk of RIRF and the determined cutoff value were 45.8% vs. 1.4% (maximum dose, {>=}42.4 Gy or less), 51.6% vs. 2.0% (V40, {>=}0.29 cm{sup 3} or less), 45.8% vs. 2.2% (V30, {>=}1.35 cm{sup 3} or less), 42.0% vs. 8.5% (V20, {>=}3.62 cm{sup 3} or less), or 25.9% vs. 10.5% (V10, {>=}5.03 cm{sup 3} or less). Conclusions: The incidence of RIRF after hypofractionated SBRT is relatively high. The maximum dose and high-dose volume are strongly correlated with RIRF.

  3. Satellite Estimates of the Direct Radiative Forcing of Biomass Burning Aerosols Over South America and Africa

    NASA Technical Reports Server (NTRS)

    Christopher, Sundar A.; Wang, Min; Kliche, Donna V.; Berendes, Todd; Welch, Ronald M.; Yang, S.K.

    1997-01-01

    Atmospheric aerosol particles, both natural and anthropogenic are important to the earth's radiative balance. Therefore it is important to provide adequate validation information on the spatial, temporal and radiative properties of aerosols. This will enable us to predict realistic global estimates of aerosol radiative effects more confidently. The current study utilizes 66 AVHRR LAC (Local Area Coverage) and coincident Earth Radiation Budget Experiment (ERBE) images to characterize the fires, smoke and radiative forcings of biomass burning aerosols over four major ecosystems of South America.

  4. Improved risk estimates for carbon tetrachloride. 1998 annual progress report

    SciTech Connect

    Benson, J.M.; Springer, D.L.; Thrall, K.D.

    1998-06-01

    'The overall purpose of these studies is to improve the scientific basis for assessing the cancer risk associated with human exposure to carbon tetrachloride. Specifically, the toxicokinetics of inhaled carbon tetrachloride is being determined in rats, mice and hamsters. Species differences in the metabolism of carbon tetrachloride by rats, mice and hamsters is being determined in vivo and in vitro using tissues and microsomes from these rodent species and man. Dose-response relationships will be determined in all studies. The information will be used to improve the current physiologically based pharmacokinetic model for carbon tetrachloride. The authors will also determine whether carbon tetrachloride is a hepatocarcinogen only when exposure results in cell damage, cell killing, and regenerative cell proliferation. In combination, the results of these studies will provide the types of information needed to enable a refined risk estimate for carbon tetrachloride under EPA''s new guidelines for cancer risk assessment.'

  5. Estimation of tuberculosis risk on a commercial airliner.

    PubMed

    Ko, Gwangpyo; Thompson, Kimberly M; Nardell, Edward A

    2004-04-01

    This article estimates the risk of tuberculosis (TB) transmission on a typical commercial airliner using a simple one box model (OBM) and a sequential box model (SBM). We used input data derived from an actual TB exposure on an airliner, and we assumed a hypothetical scenario that a highly infectious TB source case (i.e., 108 infectious quanta per hour) travels as a passenger on an 8.7-hour flight. We estimate an average risk of TB transmission on the order of 1 chance in 1,000 for all passengers using the OBM. Applying the more realistic SBM, we show that the risk and incidence decrease sharply in a stepwise fashion in cabins downstream from the cabin containing the source case assuming some potential for airflow from more contaminated to less contaminated cabins. We further characterized spatial variability in the risk within the cabin by modeling a previously reported TB outbreak in an airplane to demonstrate that the TB cases occur most likely within close proximity of the source TB patient.

  6. Interactive Decision-Support Tool for Risk-Based Radiation Therapy Plan Comparison for Hodgkin Lymphoma

    SciTech Connect

    Brodin, N. Patrik; Maraldo, Maja V.; Aznar, Marianne C.; Vogelius, Ivan R.; Petersen, Peter M.; Bentzen, Søren M.; Specht, Lena

    2014-02-01

    Purpose: To present a novel tool that allows quantitative estimation and visualization of the risk of various relevant normal tissue endpoints to aid in treatment plan comparison and clinical decision making in radiation therapy (RT) planning for Hodgkin lymphoma (HL). Methods and Materials: A decision-support tool for risk-based, individualized treatment plan comparison is presented. The tool displays dose–response relationships, derived from published clinical data, for a number of relevant side effects and thereby provides direct visualization of the trade-off between these endpoints. The Quantitative Analyses of Normal Tissue Effects in the Clinic reports were applied, complemented with newer data where available. A “relevance score” was assigned to each data source, reflecting how relevant the input data are to current RT for HL. Results: The tool is applied to visualize the local steepness of dose–response curves to drive the reoptimization of a volumetric modulated arc therapy treatment plan for an HL patient with head-and-neck involvement. We also use this decision-support tool to visualize and quantitatively evaluate the trade-off between a 3-dimensional conformal RT plan and a volumetric modulated arc therapy plan for a patient with mediastinal HL. Conclusion: This multiple-endpoint decision-support tool provides quantitative risk estimates to supplement the clinical judgment of the radiation oncologist when comparing different RT options.

  7. A method for determining weights for excess relative risk and excess absolute risk when applied in the calculation of lifetime risk of cancer from radiation exposure.

    PubMed

    Walsh, Linda; Schneider, Uwe

    2013-03-01

    , the generalization and interpretation of radiation effect estimates based on the LSS cancer data, when projected to other populations, are particularly uncertain if considerable differences exist between site-specific baseline rates in the LSS and the other populations of interest. Definitive conclusions, regarding the appropriate method for transporting cancer risks, are limited by a lack of knowledge in several areas including unknown factors and uncertainties in biological mechanisms and genetic and environmental risk factors for carcinogenesis; uncertainties in radiation dosimetry; and insufficient statistical power and/or incomplete follow-up in data from radio-epidemiological studies.

  8. Estimates of the direct and indirect radiative forcing due to tropospheric aerosols: A review

    NASA Astrophysics Data System (ADS)

    Haywood, James; Boucher, Olivier

    2000-11-01

    This paper reviews the many developments in estimates of the direct and indirect global annual mean radiative forcing due to present-day concentrations of anthropogenic tropospheric aerosols since Intergovernmental Panel on Climate Change [1996]. The range of estimates of the global mean direct radiative forcing due to six distinct aerosol types is presented. Additionally, the indirect effect is split into two components corresponding to the radiative forcing due to modification of the radiative properties of clouds (cloud albedo effect) and the effects of anthropogenic aerosols upon the lifetime of clouds (cloud lifetime effect). The radiative forcing for anthropogenic sulphate aerosol ranges from -0.26 to -0.82 W m-2. For fossil fuel black carbon the radiative forcing ranges from +0.16 W m-2 for an external mixture to +0.42 W m-2 for where the black carbon is modeled as internally mixed with sulphate aerosol. For fossil fuel organic carbon the two estimates of the likely weakest limit of the direct radiative forcing are -0.02 and -0.04 W m-2. For biomass-burning sources of black carbon and organic carbon the combined radiative forcing ranges from -0.14 to -0.74 W m-2. Estimates of the radiative forcing due to mineral dust vary widely from +0.09 to -0.46 W m-2; even the sign of the radiative forcing is not well established due to the competing effects of solar and terrestrial radiative forcings. A single study provides a very tentative estimate of the radiative forcing of nitrates to be -0.03 W m-2. Estimates of the cloud albedo indirect radiative forcing range from -0.3 to approximately -1.8 W m-2. Although the cloud lifetime effect is identified as a potentially important climate forcing mechanism, it is difficult to quantify in the context of the present definition of radiative forcing of climate change and current model simulations. This is because its estimation by general circulation models necessarily includes some level of cloud and water vapor feedbacks

  9. RISKS AND RADIATION DOSES DUE TO RESIDENTIAL RADON IN GERMANY.

    PubMed

    Beck, T R

    2017-01-10

    The population-averaged risk rate and the annual average effective dose due to residential radon in Germany were calculated. The calculations were based on an epidemiological approach taking into account the age- and gender-specific lung cancer incidence rates for the German population and the excess relative risk of 0.16 per 100 Bq·m(-3) for residential radon. In addition, the risk estimates adjusted for the smoking habits were determined. The population-averaged risk rate for the whole population was estimated with 4.1·10(-5) y(-1) (95% confidence interval (CI) 1.4·10(-5)-7.6·10(-5) y(-1)). Residential radon causes a detriment per year of 3.3·10(-5) y(-1) (95% CI 1.1·10(-5)-6.0·10(-5) y(-1)), which corresponds to an annual average effective dose of 0.6 mSv (95% CI 0.2-1.1 mSv). Annually, ~3400 lung cancer incidences are attributed to residential radon. The results from the epidemiological approach exercised in this study are considerably lower than the effective dose, which would be obtained from the dose conversion coefficient calculated using biokinetic and dosimetric models.

  10. Risk evaluation - conventional and low level effects of radiation

    SciTech Connect

    Bond, V.P.; Varma, M.N.

    1984-04-01

    Any discussion of the risk of exposure to potentially-hazardous agents in the environment inevitably involves the question of whether the dose effect curve is of the threshold or linear, non-threshold type. A principal objective of this presentation is to show that the function is actually two separate relationships, each representing distinctly different functions with differing variables on the axes, and each characteristic of quite different functions with differing variables on the axes, and each characteristic of quite different disciplines (i.e., the threshold function, of Pharmacology, Toxicology and Medicine (PTM); the linear, non-threshold function, of Public Health including safety and accident statistics (PHS)). It is shown that low-level exposure (LLE) to radiation falls clearly in the PHS category. A function for cell dose vs. the fraction of single cell quantal responses is characterized, which reflects the absolute and relative sensitivities of cells. Acceptance of this function would obviate any requirement for the use in Radiation Protection of the concepts of a standard radiation, Q, dose equivalent and rem. 9 references, 4 figures.

  11. Estimated Ultraviolet Radiation Doses in Wetlands in Six National Parks

    EPA Science Inventory

    Ultraviolet radiation (UVR) has been suggested as a potential cause of population declines and increases in malformations in amphibians. This study indicates that the present distributions of amphibians in four western U.S. National Parks are not related to UVR exposure, and sugg...

  12. ESTIMATION OF UV RADIATION DOSE IN NORTHERN MINNESOTA WETLANDS

    EPA Science Inventory

    The ultraviolet (UV) B wavelength range (280 nm to 320 nm) of solar radiation can be a significant biological stressor, and has been hypothesized to be partially responsible for amphibian declines and malformation. This hypothesis has been difficult to evaluate, in part, because ...

  13. A case-control study of ultraviolet radiation exposure, vitamin D, and lymphoma risk in adults

    PubMed Central

    Kelly, Jennifer L.; Friedberg, Jonathan W.; Calvi, Laura M.; van Wijngaarden, Edwin; Fisher, Susan G.

    2010-01-01

    Recent research suggests that ultraviolet radiation exposure (UVRE), our major source of vitamin D, is associated with reduced lymphoma risk. Animal and human studies support an association between vitamin D (vitD) insufficiency and increased risk of some malignancies. We conducted a clinic-based case-control study (140 lymphoma cases, 139 controls; 2002–2005, Rochester, NY) to evaluate UVRE and vitD insufficiency in relation to lymphoma risk. Subjects completed a survey and provided a blood sample. We used multivariable logistic regression to estimate lymphoma risk in relation to past (5–10 years prior) UVRE and current vitD insufficiency (determined by serum 25(OH)D). Possible differences in effect by lymphoma subtype were explored, but statistical power was limited. We confirmed the previously reported decrease in lymphoma risk with past UVRE, specifically sunbathing (>once/week versus never); adjusted odds ratio (ORadj), = 0.28, 95% confidence interval (CI): 0.10–0.79. Current vitD insufficiency was not associated with lymphoma risk (ORadj=0.89, 95% CI: 0.47–1.72). However, current sunbathing frequency was correlated with measured serum 25(OH)D values. Therefore, while our data do not support an association with current vitD status, development of accurate methods for past vitD assessment to further investigate its role in the association between past UVRE and lymphoma risk is warranted. PMID:20373010

  14. Effects of radiation and lifestyle factors on risks of urothelial carcinoma in the Life Span Study of atomic bomb survivors.

    PubMed

    Grant, E J; Ozasa, K; Preston, D L; Suyama, A; Shimizu, Y; Sakata, R; Sugiyama, H; Pham, T-M; Cologne, J; Yamada, M; De Roos, A J; Kopecky, K J; Porter, M P; Seixas, N; Davis, S

    2012-07-01

    Among the Life Span Study (LSS) of Atomic-bomb survivors, recent estimates showed that unspecified bladder cancer had high radiation sensitivity with a notably high female-to-male excess relative risk (ERR) per radiation dose ratio and were the only sites for which the ERR did not decrease with attained age. These findings, however, did not consider lifestyle factors, which could potentially confound or modify the risk estimates. This study estimated the radiation risks of the most prevalent subtype of urinary tract cancer, urothelial carcinoma, while accounting for smoking, consumption of fruit, vegetables, alcohol and level of education (a surrogate for socioeconomic status). Eligible study subjects included 105,402 (males = 42,890) LSS members who were cancer-free in 1958 and had estimated radiation doses. Members were censored due to loss of follow-up, incident cancer of another type, death, or the end of calendar year 2001. Surveys (by mail or clinical interview) gathered lifestyle data periodically for 1963-1991. There were 63,827 participants in one or more survey. Five hundred seventy-three incident urothelial carcinoma cases occurred, of which 364 occurred after lifestyle information was available. Analyses were performed using Poisson regression methods. The excess relative risk per weighted gray unit (the gamma component plus 10 times the neutron component, Gy(w)) was 1.00 (95% CI: 0.43-1.78) but the risks were not dependent upon age at exposure or attained age. Lifestyle factors other than smoking were not associated with urothelial carcinoma risk. Neither the magnitude of the radiation ERR estimate (1.00 compared to 0.96), nor the female-to-male (F:M) ERR/Gy(w) ratio (3.2 compared to 3.4) were greatly changed after accounting for all lifestyle factors. A multiplicative model of gender-specific radiation and smoking effects was the most revealing though there was no evidence of significant departures from either the additive or multiplicative joint

  15. Estimating radiation dose to organs of patients undergoing conventional and novel multidetector CT exams using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Angel, Erin

    Advances in Computed Tomography (CT) technology have led to an increase in the modality's diagnostic capabilities and therefore its utilization, which has in turn led to an increase in radiation exposure to the patient population. As a result, CT imaging currently constitutes approximately half of the collective exposure to ionizing radiation from medical procedures. In order to understand the radiation risk, it is necessary to estimate the radiation doses absorbed by patients undergoing CT imaging. The most widely accepted risk models are based on radiosensitive organ dose as opposed to whole body dose. In this research, radiosensitive organ dose was estimated using Monte Carlo based simulations incorporating detailed multidetector CT (MDCT) scanner models, specific scan protocols, and using patient models based on accurate patient anatomy and representing a range of patient sizes. Organ dose estimates were estimated for clinical MDCT exam protocols which pose a specific concern for radiosensitive organs or regions. These dose estimates include estimation of fetal dose for pregnant patients undergoing abdomen pelvis CT exams or undergoing exams to diagnose pulmonary embolism and venous thromboembolism. Breast and lung dose were estimated for patients undergoing coronary CTA imaging, conventional fixed tube current chest CT, and conventional tube current modulated (TCM) chest CT exams. The correlation of organ dose with patient size was quantified for pregnant patients undergoing abdomen/pelvis exams and for all breast and lung dose estimates presented. Novel dose reduction techniques were developed that incorporate organ location and are specifically designed to reduce close to radiosensitive organs during CT acquisition. A generalizable model was created for simulating conventional and novel attenuation-based TCM algorithms which can be used in simulations estimating organ dose for any patient model. The generalizable model is a significant contribution of this

  16. Cardiovascular risks associated with low dose ionizing particle radiation.

    PubMed

    Yan, Xinhua; Sasi, Sharath P; Gee, Hannah; Lee, JuYong; Yang, Yongyao; Mehrzad, Raman; Onufrak, Jillian; Song, Jin; Enderling, Heiko; Agarwal, Akhil; Rahimi, Layla; Morgan, James; Wilson, Paul F; Carrozza, Joseph; Walsh, Kenneth; Kishore, Raj; Goukassian, David A

    2014-01-01

    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 ((1)H; 0.5 Gy, 1 GeV) and iron ion ((56)Fe; 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 (56)Fe ion-irradiated mice at 1 and 3 months but recovered at 10 months. In addition, (56)Fe 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.

  17. Cardiovascular Risks Associated with Low Dose Ionizing Particle Radiation

    DOE PAGES

    Yan, Xinhua; Sasi, Sharath P.; Gee, Hannah; ...

    2014-10-22

    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 initiallymore » 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. Finally, 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.« less

  18. Cardiovascular Risks Associated with Low Dose Ionizing Particle Radiation

    SciTech Connect

    Yan, Xinhua; Sasi, Sharath P.; Gee, Hannah; Lee, JuYong; Yang, Yongyao; Mehrzad, Raman; Onufrak, Jillian; Song, Jin; Enderling, Heiko; Agarwal, Akhil; Rahimi, Layla; Morgan, James; Wilson, Paul F.; Carrozza, Joseph; Walsh, Kenneth; Kishore, Raj; Goukassian, David A.

    2014-10-22

    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. Finally, 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.

  19. Cardiovascular Risks Associated with Low Dose Ionizing Particle Radiation

    PubMed Central

    Yan, Xinhua; Sasi, Sharath P.; Gee, Hannah; Lee, JuYong; Yang, Yongyao; Mehrzad, Raman; Onufrak, Jillian; Song, Jin; Enderling, Heiko; Agarwal, Akhil; Rahimi, Layla; Morgan, James; Wilson, Paul F.; Carrozza, Joseph; Walsh, Kenneth; Kishore, Raj; Goukassian, David A.

    2014-01-01

    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. PMID:25337914

  20. Risky Business: The Science and Art of Radiation Risk Communication in the High Risk Context of Space Travel

    NASA Technical Reports Server (NTRS)

    Elgart, Shona Robin; Shavers, Mark; Huff, Janice; Patel, Zarana; Semones, Edward

    2016-01-01

    Successfully communicating the complex risks associated with radiation exposure is a difficult undertaking; communicating those risks within the high-risk context of space travel is uniquely challenging. Since the potential risks of space radiation exposure are not expected to be realized until much later in life, it is hard to draw comparisons between other spaceflight risks such as hypoxia and microgravity-induced bone loss. Additionally, unlike other spaceflight risks, there is currently no established mechanism to mitigate the risks of incurred radiation exposure such as carcinogenesis. Despite these challenges, it is the duty of the Space Radiation Analysis Group (SRAG) at NASA's Johnson Space Center to provide astronauts with the appropriate information to effectively convey the risks associated with exposure to the space radiation environment. To this end, astronauts and their flight surgeons are provided with an annual radiation risk report documenting the astronaut's individual radiation exposures from space travel, medical, and internal radiological procedures throughout the astronaut's career. In an effort to improve this communication and education tool, this paper critically reviews the current report style and explores alternative report styles to define best methods to appropriately communicate risk to astronauts, flight surgeons, and management.

  1. How Many Significant Figures are Useful for Public Risk Estimates?

    NASA Astrophysics Data System (ADS)

    Wilde, Paul D.; Duffy, Jim

    2013-09-01

    This paper considers the level of uncertainty in the calculation of public risks from launch or reentry and provides guidance on the number of significant digits that can be used with confidence when reporting the analysis results to decision-makers. The focus of this paper is the uncertainty in collective risk calculations that are used for launches of new and mature ELVs. This paper examines the computational models that are used to estimate total collective risk to the public for a launch, including the model input data and the model results, and characterizes the uncertainties due to both bias and variability. There have been two recent efforts to assess the uncertainty in state-of-the-art risk analysis models used in the US and their input data. One assessment focused on launch area risk from an Atlas V at Vandenberg Air Force Base (VAFB) and the other focused on downrange risk to Eurasia from a Falcon 9 launched from Cape Canaveral Air Force Station (CCAFS). The results of these studies quantified the uncertainties related to both the probability and the consequence of the launch debris hazards. This paper summarizes the results of both of these relatively comprehensive launch risk uncertainty analyses, which addressed both aleatory and epistemic uncertainties. The epistemic uncertainties of most concern were associated with probability of failure and the debris list. Other major sources of uncertainty evaluated were: the casualty area for people in shelters that are impacted by debris, impact distribution size, yield from exploding propellant and propellant tanks, probability of injury from a blast wave for people in shelters or outside, and population density. This paper also summarizes a relatively comprehensive over-flight risk uncertainty analysis performed by the FAA for the second stage of flight for a Falcon 9 from CCAFS. This paper is applicable to baseline collective risk analyses, such as those used to make a commercial license determination, and

  2. Seismic Risk Assessment and Loss Estimation for Tbilisi City

    NASA Astrophysics Data System (ADS)

    Tsereteli, Nino; Alania, Victor; Varazanashvili, Otar; Gugeshashvili, Tengiz; Arabidze, Vakhtang; Arevadze, Nika; Tsereteli, Emili; Gaphrindashvili, Giorgi; Gventcadze, Alexander; Goguadze, Nino; Vephkhvadze, Sophio

    2013-04-01

    The proper assessment of seismic risk is of crucial importance for society protection and city sustainable economic development, as it is the essential part to seismic hazard reduction. Estimation of seismic risk and losses is complicated tasks. There is always knowledge deficiency on real seismic hazard, local site effects, inventory on elements at risk, infrastructure vulnerability, especially for developing countries. Lately great efforts was done in the frame of EMME (earthquake Model for Middle East Region) project, where in the work packages WP1, WP2 , WP3 and WP4 where improved gaps related to seismic hazard assessment and vulnerability analysis. Finely in the frame of work package wp5 "City Scenario" additional work to this direction and detail investigation of local site conditions, active fault (3D) beneath Tbilisi were done. For estimation economic losses the algorithm was prepared taking into account obtained inventory. The long term usage of building is very complex. It relates to the reliability and durability of buildings. The long term usage and durability of a building is determined by the concept of depreciation. Depreciation of an entire building is calculated by summing the products of individual construction unit' depreciation rates and the corresponding value of these units within the building. This method of calculation is based on an assumption that depreciation is proportional to the building's (constructions) useful life. We used this methodology to create a matrix, which provides a way to evaluate the depreciation rates of buildings with different type and construction period and to determine their corresponding value. Finally loss was estimated resulting from shaking 10%, 5% and 2% exceedance probability in 50 years. Loss resulting from scenario earthquake (earthquake with possible maximum magnitude) also where estimated.

  3. Estimating the Infrared Radiation Wavelength Emitted by a Remote Control Device Using a Digital Camera

    ERIC Educational Resources Information Center

    Catelli, Francisco; Giovannini, Odilon; Bolzan, Vicente Dall Agnol

    2011-01-01

    The interference fringes produced by a diffraction grating illuminated with radiation from a TV remote control and a red laser beam are, simultaneously, captured by a digital camera. Based on an image with two interference patterns, an estimate of the infrared radiation wavelength emitted by a TV remote control is made. (Contains 4 figures.)

  4. ULTRAVIOLET RADIATION IN NORTH AMERICAN LAKES: ATTENUATION ESTIMATES FROM DOC MEASUREMENTS AND IMPLICATIONS FOR PLANKTON COMMUNITIES

    EPA Science Inventory

    Climate warming in North America is likely to be accompanied by changes in other environmental stresses such as UV-B radiation. We apply an empirical model to available DOC (dissolved organic C) data to estimate the depths to which 1% of surface UV-B and UV-A radiation penetrate ...

  5. Electromagnetic radiation and health risks: Cell phones and microwave radiation in New Zealand

    SciTech Connect

    Smith, I.

    1996-07-01

    Presently the public is concerned over the proliferation of cellphone repeater sites around the cities of New Zealand and whether they pose a risk to health. The debate continued for some weeks over the proposal to erect a cellphone repeater in a school yard. The issues that came out of that debate are profiled in this paper -- environmental health professionals need to be able to communicate well-judged advice to their employers. Cellular phone networks use relatively low-powered transmitters to restrict coverage to a circumscribed locality and thereby enable particular carrier frequencies to be used simultaneously at different cell sites in the same general area. Compared with TV and radio broadcasting, the radiation power levels near cell sites are therefore relatively small. Broadcast transmission antennae are designed to confine the radiation so that it doesn`t go in directions where it is not required or not wanted.

  6. GERMcode: A Stochastic Model for Space Radiation Risk Assessment

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Ponomarev, Artem L.; Cucinotta, Francis A.

    2012-01-01

    A new computer model, the GCR Event-based Risk Model code (GERMcode), was developed to describe biophysical events from high-energy protons and high charge and energy (HZE) particles that have been studied at the NASA Space Radiation Laboratory (NSRL) for the purpose of simulating space radiation biological effects. In the GERMcode, the biophysical description of the passage of HZE particles in tissue and shielding materials is made with a stochastic approach that includes both particle track structure and nuclear interactions. The GERMcode accounts for the major nuclear interaction processes of importance for describing heavy ion beams, including nuclear fragmentation, elastic scattering, and knockout-cascade processes by using the quantum multiple scattering fragmentation (QMSFRG) model. The QMSFRG model has been shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections. For NSRL applications, the GERMcode evaluates a set of biophysical properties, such as the Poisson distribution of particles or delta-ray hits for a given cellular area and particle dose, the radial dose on tissue, and the frequency distribution of energy deposition in a DNA volume. By utilizing the ProE/Fishbowl ray-tracing analysis, the GERMcode will be used as a bi-directional radiation transport model for future spacecraft shielding analysis in support of Mars mission risk assessments. Recent radiobiological experiments suggest the need for new approaches to risk assessment that include time-dependent biological events due to the signaling times for activation and relaxation of biological processes in cells and tissue. Thus, the tracking of the temporal and spatial distribution of events in tissue is a major goal of the GERMcode in support of the simulation of biological processes important in GCR risk assessments. In order to validate our approach, basic radiobiological responses such as cell survival curves, mutation, chromosomal

  7. Radiation risk of individual multifactorial diseases in offspring of the atomic-bomb survivors: a clinical health study.

    PubMed

    Tatsukawa, Yoshimi; Cologne, John B; Hsu, Wan-Ling; Yamada, Michiko; Ohishi, Waka; Hida, Ayumi; Furukawa, Kyoji; Takahashi, Norio; Nakamura, Nori; Suyama, Akihiko; Ozasa, Kotaro; Akahoshi, Masazumi; Fujiwara, Saeko; Shore, Roy

    2013-06-01

    There is no convincing evidence regarding radiation-induced heritable risks of adult-onset multifactorial diseases in humans, although it is important from the standpoint of protection and management of populations exposed to radiation. The objective of the present study was to examine whether parental exposure to atomic-bomb (A-bomb) radiation led to an increased risk of common polygenic, multifactorial diseases-hypertension, hypercholesterolaemia, diabetes mellitus, angina pectoris, myocardial infarction or stroke-in the first-generation (F1) offspring of A-bomb survivors. A total of 11,951 F1 offspring of survivors in Hiroshima or Nagasaki, conceived after the bombing, underwent health examinations to assess disease prevalence. We found no evidence that paternal or maternal A-bomb radiation dose, or the sum of their doses, was associated with an increased risk of any multifactorial diseases in either male or female offspring. None of the 18 radiation dose-response slopes, adjusted for other risk factors for the diseases, was statistically significantly elevated. However, the study population is still in mid-life (mean age 48.6 years), and will express much of its multifactorial disease incidence in the future, so ongoing longitudinal follow-up will provide increasingly informative risk estimates regarding hereditary genetic effects for incidence of adult-onset multifactorial disease.

  8. Reproductive Status at First Diagnosis Influences Risk of Radiation-Induced Second Primary Contralateral Breast Cancer in the WECARE Study

    SciTech Connect

    Brooks, Jennifer D.; Boice, John D.; Stovall, Marilyn; Reiner, Anne S.; Bernstein, Leslie; John, Esther M.; Lynch, Charles F.; Mellemkjaer, Lene; Knight, Julia A.; Thomas, Duncan C.; Haile, Robert W.; Smith, Susan A.; Capanu, Marinela; Bernstein, Jonine L.; Shore, Roy E.

    2012-11-15

    Purpose: Our study examined whether reproductive and hormonal factors before, at the time of, or after radiation treatment for a first primary breast cancer modify the risk of radiation-induced second primary breast cancer. Methods and Materials: The Women's Environmental, Cancer and Radiation Epidemiology (WECARE) Study is a multicenter, population-based study of 708 women (cases) with asynchronous contralateral breast cancer (CBC) and 1399 women (controls) with unilateral breast cancer. Radiotherapy (RT) records, coupled with anthropomorphic phantom simulations, were used to estimate quadrant-specific radiation dose to the contralateral breast for each patient. Rate ratios (RR) and 95% confidence intervals (CI) were computed to assess the relationship between reproductive factors and risk of CBC. Results: Women who were nulliparous at diagnosis and exposed to {>=}1 Gy to the contralateral breast had a greater risk for CBC than did matched unexposed nulliparous women (RR = 2.2; 95% CI, 1.2-4.0). No increased risk was seen in RT-exposed parous women (RR = 1.1; 95% CI, 0.8-1.4). Women treated with RT who later became pregnant (8 cases and 9 controls) had a greater risk for CBC (RR = 6.0; 95% CI, 1.3-28.4) than unexposed women (4 cases and 7 controls) who also became pregnant. The association of radiation with risk of CBC did not vary by number of pregnancies, history of breastfeeding, or menopausal status at the time of first breast cancer diagnosis. Conclusion: Nulliparous women treated with RT were at an increased risk for CBC. Although based on small numbers, women who become pregnant after first diagnosis also seem to be at an increased risk for radiation-induced CBC.

  9. Leukemia risk associated with benzene exposure in the pliofilm cohort. II. Risk estimates.

    PubMed

    Paxton, M B; Chinchilli, V M; Brett, S M; Rodricks, J V

    1994-04-01

    The detailed work histories of the individual workers composing the Pliofilm cohort represent a unique resource for estimating the dose-response for leukemia that may follow occupational exposure to benzene. In this paper, we report the results of analyzing the updated Pliofilm cohort using the proportional hazards model, a more sophisticated technique that uses more of the available exposure data than the conditional logistic model used by Rinsky et al. The more rigorously defined exposure estimates derived by Paustenbach et al. are consistent with those of Crump and Allen in giving estimates of the slope of the leukemogenic dose-response that are not as steep as the slope resulting from the exposure estimates of Rinsky et al. We consider estimates of 0.3-0.5 additional leukemia deaths per thousand workers with 45 ppm-years of cumulative benzene exposure to be the best estimates currently available of leukemia risk from occupational exposure to benzene. These risks were estimated in the proportional hazards model when the exposure estimates of Crump and Allen or of Paustenbach et al. were used to derive a cumulative concentration-by-time metric.

  10. Estimating twin concordance for bivariate competing risks twin data.

    PubMed

    Scheike, Thomas H; Holst, Klaus K; Hjelmborg, Jacob B

    2014-03-30

    For twin time-to-event data, we consider different concordance probabilities, such as the casewise concordance that are routinely computed as a measure of the lifetime dependence/correlation for specific diseases. The concordance probability here is the probability that both twins have experienced the event of interest. Under the assumption that both twins are censored at the same time, we show how to estimate this probability in the presence of right censoring, and as a consequence, we can then estimate the casewise twin concordance. In addition, we can model the magnitude of within pair dependence over time, and covariates may be further influential on the marginal risk and dependence structure. We establish the estimators large sample properties and suggest various tests, for example, for inferring familial influence. The method is demonstrated and motivated by specific twin data on cancer events with the competing risk death. We thus aim to quantify the degree of dependence through the casewise concordance function and show a significant genetic component.

  11. INTERACTION OF LASER RADIATION WITH MATTER: Estimates of phase-transition heats in steels and ceramics heated by laser radiation

    NASA Astrophysics Data System (ADS)

    Tsar'kova, O. G.; Garnov, Sergei V.

    2003-08-01

    Measurements of the high-temperature dependences of the heat capacity of solids heated by high-power laser radiation and the model of formation of structural point defects (vacancies) are used to estimate the heats of sublimation, evaporation and melting, as well as enthalpy of phase transformations for modern processing of steels and ceramics.

  12. Cancer Risk Estimates from Space Flight Estimated Using Yields of Chromosome Damage in Astronaut's Blood Lymphocytes

    NASA Technical Reports Server (NTRS)

    George, Kerry A.; Rhone, J.; Chappell, L. J.; Cucinotta, F. A.

    2011-01-01

    To date, cytogenetic damage has been assessed in blood lymphocytes from more than 30 astronauts before and after they participated in long-duration space missions of three months or more on board the International Space Station. Chromosome damage was assessed using fluorescence in situ hybridization whole chromosome analysis techniques. For all individuals, the frequency of chromosome damage measured within a month of return from space was higher than their preflight yield, and biodosimetry estimates were within the range expected from physical dosimetry. Follow up analyses have been performed on most of the astronauts at intervals ranging from around 6 months to many years after flight, and the cytogenetic effects of repeat long-duration missions have so far been assessed in four individuals. Chromosomal aberrations in peripheral blood lymphocytes have been validated as biomarkers of cancer risk and cytogenetic damage can therefore be used to characterize excess health risk incurred by individual crewmembers after their respective missions. Traditional risk assessment models are based on epidemiological data obtained on Earth in cohorts exposed predominantly to acute doses of gamma-rays, and the extrapolation to the space environment is highly problematic, involving very large uncertainties. Cytogenetic damage could play a key role in reducing uncertainty in risk estimation because it is incurred directly in the space environment, using specimens from the astronauts themselves. Relative cancer risks were estimated from the biodosimetry data using the quantitative approach derived from the European Study Group on Cytogenetic Biomarkers and Health database. Astronauts were categorized into low, medium, or high tertiles according to their yield of chromosome damage. Age adjusted tertile rankings were used to estimate cancer risk and results were compared with values obtained using traditional modeling approaches. Individual tertile rankings increased after space

  13. Exposure to diagnostic radiation and risk of breast cancer among carriers of BRCA1/2 mutations: retrospective cohort study (GENE-RAD-RISK)

    PubMed Central

    Pijpe, Anouk; Andrieu, Nadine; Easton, Douglas F; Kesminiene, Ausrele; Cardis, Elisabeth; Noguès, Catherine; Gauthier-Villars, Marion; Lasset, Christine; Fricker, Jean-Pierre; Peock, Susan; Frost, Debra; Evans, D Gareth; Eeles, Rosalind A; Paterson, Joan; Manders, Peggy; van Asperen, Christi J; Ausems, Margreet G E M; Meijers-Heijboer, Hanne; Thierry-Chef, Isabelle; Hauptmann, Michael; Goldgar, David; Rookus, Matti A

    2012-01-01

    Objective To estimate the risk of breast cancer associated with diagnostic radiation in carriers of BRCA1/2 mutations. Design Retrospective cohort study (GENE-RAD-RISK). Setting Three nationwide studies (GENEPSO, EMBRACE, HEBON) in France, United Kingdom, and the Netherlands, Participants 1993 female carriers of BRCA1/2 mutations recruited in 2006-09. Main outcome measure Risk of breast cancer estimated with a weighted Cox proportional hazards model with a time dependent individually estimated cumulative breast dose, based on nominal estimates of organ dose and frequency of self reported diagnostic procedures. To correct for potential survival bias, the analysis excluded carriers who were diagnosed more than five years before completion of the study questionnaire. Results In carriers of BRCA1/2 mutations any exposure to diagnostic radiation before the age of 30 was associated with an increased risk of breast cancer (hazard ratio 1.90, 95% confidence interval 1.20 to 3.00), with a dose-response pattern. The risks by quarter of estimated cumulative dose <0.0020 Gy, ≥0.0020-0.0065 Gy, ≥0.0066-0.0173 Gy, and ≥0.0174 Gy were 1.63 (0.96 to 2.77), 1.78 (0.88 to 3.58), 1.75 (0.72 to 4.25), and 3.84 (1.67 to 8.79), respectively. Analyses on the different types of diagnostic procedures showed a pattern of increasing risk with increasing number of radiographs before age 20 and before age 30 compared with no exposure. A history of mammography before age 30 was also associated with an increased risk of breast cancer (hazard ratio 1.43, 0.85 to 2.40). Sensitivity analysis showed that this finding was not caused by confounding by indication of family history. Conclusion In this large European study among carriers of BRCA1/2 mutations, exposure to diagnostic radiation before age 30 was associated with an increased risk of breast cancer at dose levels considerably lower than those at which increases have been found in other cohorts exposed to radiation. The results of this

  14. Data Sources for the Model-based Small Area Estimates of Cancer Risk Factors and Screening Behaviors - Small Area Estimates

    Cancer.gov

    The model-based estimates of important cancer risk factors and screening behaviors are obtained by combining the responses to the Behavioral Risk Factor Surveillance System (BRFSS) and the National Health Interview Survey (NHIS).

  15. Spatio-temporal population estimates for risk management

    NASA Astrophysics Data System (ADS)

    Cockings, Samantha; Martin, David; Smith, Alan; Martin, Rebecca

    2013-04-01

    Accurate estimation of population at risk from hazards and effective emergency management of events require not just appropriate spatio-temporal modelling of hazards but also of population. While much recent effort has been focused on improving the modelling and predictions of hazards (both natural and anthropogenic), there has been little parallel advance in the measurement or modelling of population statistics. Different hazard types occur over diverse temporal cycles, are of varying duration and differ significantly in their spatial extent. Even events of the same hazard type, such as flood events, vary markedly in their spatial and temporal characteristics. Conceptually and pragmatically then, population estimates should also be available for similarly varying spatio-temporal scales. Routine population statistics derived from traditional censuses or surveys are usually static representations in both space and time, recording people at their place of usual residence on census/survey night and presenting data for administratively defined areas. Such representations effectively fix the scale of population estimates in both space and time, which is unhelpful for meaningful risk management. Over recent years, the Pop24/7 programme of research, based at the University of Southampton (UK), has developed a framework for spatio-temporal modelling of population, based on gridded population surfaces. Based on a data model which is fully flexible in terms of space and time, the framework allows population estimates to be produced for any time slice relevant to the data contained in the model. It is based around a set of origin and destination centroids, which have capacities, spatial extents and catchment areas, all of which can vary temporally, such as