Science.gov

Sample records for current radiation risk

  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. Current trends in estimating risk of cancer from exposure to low doses of ionising radiation.

    PubMed

    Majer, Marija; Knežević, Zeljka; Saveta, Miljanić

    2014-09-29

    Although ionising radiation has proven beneficial in the diagnosis and therapy of a number of diseases, one should keep in mind that irradiating healthy tissue may increase the risk of cancer. In order to justify an exposure to radiation, both the benefits and the risks must be evaluated and compared. The deleterious effects of medium and high doses are well known, but it is much less clear what effects arise from low doses (below 0.1 Gy), which is why such risk estimates are extremely important. This review presents the current state, important assumptions and steps being made in deriving cancer risk estimates for low dose exposures.

  3. [Diagnostic radiation exposure in children and cancer risk: current knowledge and perspectives].

    PubMed

    Baysson, H; Etard, C; Brisse, H J; Bernier, M-O

    2012-01-01

    The question of the risk of cancer associated with postnatal diagnostic medical exposure involving ionizing radiation in childhood is particularly relevant at the moment given the growing use of diagnostic examinations, especially computed tomography scans, in children. Compared to adults, pediatric patients are more sensitive to radiation and have more years of life expectancy and therefore more years at risk of cancer occurrence as compared to adults. This paper provides a description of diagnostic x-ray exposure in children in France and summarizes epidemiologic studies on subsequent risk of cancer. Overall, this review, based on 12 case-control studies and 6 cohort studies, shows no significant association between exposure to medical diagnostic radiation exposure and childhood cancer risk. The methodological limitations of these studies are discussed. As the expected cancer risks are low, epidemiological studies require very large sample sizes and long periods of follow-up in addition to a good dosimetry assessment to enable quantitative risk estimation. New cohort studies of young patients who underwent CT scans are currently underway within the European EPI-CT project. In the meantime, continued efforts to reduce doses and the number of radiological examinations in children are needed, including adhering to the "as long as reasonably achievable" (Alara) principle. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  4. Exposing the Thyroid to Radiation: A Review of Its Current Extent, Risks, and Implications

    PubMed Central

    Sinnott, Bridget; Ron, Elaine; Schneider, Arthur B.

    2010-01-01

    Radiation exposure of the thyroid at a young age is a recognized risk factor for the development of differentiated thyroid cancer lasting for four decades and probably for a lifetime after exposure. Medical radiation exposure, however, occurs frequently, including among the pediatric population, which is especially sensitive to the effects of radiation. In the past, the treatment of benign medical conditions with external radiation represented the most significant thyroid radiation exposures. Today, diagnostic medical radiation represents the largest source of man-made radiation exposure. Radiation exposure related to the use of computerized tomography is rising exponentially, particularly in the pediatric population. There is direct epidemiological evidence of a small but significant increased risk of cancer at radiation doses equivalent to computerized tomography doses used today. Paralleling the increasing use of medical radiation is an increase in the incidence of papillary thyroid cancer. At present, it is unclear how much of this increase is related to increased detection of subclinical disease from the increased utilization of ultrasonography and fine-needle aspiration, how much is due to a true increase in thyroid cancer, and how much, if any, can be ascribed to medical radiation exposure. Fortunately, the amount of radiation exposure from medical sources can be reduced. In this article we review the sources of thyroid radiation exposure, radiation risks to the thyroid gland, strategies for reducing radiation exposure to the thyroid, and ways that endocrinologists can participate in this effort. Finally, we provide some suggestions for future research directions. PMID:20650861

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. Ring current and radiation belts

    NASA Technical Reports Server (NTRS)

    Williams, D. J.

    1987-01-01

    Studies performed during 1983-1986 on the ring current, the injection boundary model, and the radiation belts are discussed. The results of these studies yielded the first observations on the composition and charge state of the ring current throughout the ring-current energy range, and strong observational support for an injection-boundary model accounting for the origins of radiation-belt particles, the ring current, and substorm particles observed at R less than about 7 earth radii. In addition, the results have demonstrated that the detection of energetic neutral atoms generated by charge-exchange interactions between the ring current and the hydrogen geocorona can provide global images of the earth's ring current and its spatial and temporal evolution.

  10. Current State and Problems of Radiation Risk Communication: Based on the Results of a 2012 Whole Village Survey

    PubMed Central

    Kuroda, Yujiro

    2017-01-01

    Purpose: The entire village of Iitate was contaminated by radioactive material from the Fukushima Daiichi Nuclear Power Plant; even today, the residents remain evacuated. For the villagers, risk communication is an important element of recovery and maintaining health. This analysis focuses on the problem of radiation, presents results from a questionnaire of villagers, and examines methods for future risk communication activities. Subjects and Methods: In May 2012, anonymous surveys were sent to 2914 heads of households whose addresses were registered in Iitate. Their understanding of radiation and information needs were extracted from the answers. Results and Discussion: There were 1755 valid responses (61.4%). In relation to understanding, the most frequent answer was “There are numerous opinions and I do not know which one is true” (72.2%), followed by “I definitely want opportunities to learn more about how radiation is created” (41.6%). Residents felt that they could not determine which of the available information was reliable. The 60s+ age group responded more than younger age groups that “I do not have much information and do not know much about it,” “I do not know much about it, so I want to learn more,” and “I definitely want opportunities to learn more about how radiation is created.” Among information needs, “publications” (50.2%) and “community associations” (45.9%) received many responses; residents want study groups to be held at places and through media that give them regular opportunities to connect with each other. Residents in their 20s and 30s preferred “publications,” while those in their 40s, 50s, and 60s+ were more likely to request “community associations” and “resident meetings.” In addition, we found gender differences in both understanding and information needs. These results indicate that radiation and health risk communication should be addressed in a way that aligns with residents’ needs by age

  11. 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.

  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. 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.

  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. 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)

  17. New radiobiological, radiation risk and radiation protection paradigms.

    PubMed

    Goodhead, Dudley T

    2010-05-01

    The long-standing conventional paradigm for radiobiology has formed a logical basis for the standard paradigm for radiation risk of cancer and heritable effects and, from these paradigms, has developed the internationally applied system for radiation protection, but with many simplifications, assumptions and generalizations. A variety of additional radiobiological phenomena that do not conform to the standard paradigm for radiobiology may have potential implications for radiation risk and radiation protection. It is suggested, however, that the current state of knowledge is still insufficient for these phenomena, individually or collectively, to be formulated systematically into a new paradigm for radiobiology. Additionally, there is at present lack of direct evidence of their relevance to risk for human health, despite attractive hypotheses as to how they might be involved. Finally, it remains to be shown how incorporation of such phenomena into the paradigm for radiation protection would provide sufficient added value to offset disruption to the present widely applied system. Further research should aim for better mechanistic understanding of processes such as radiation-induced genomic instability (for all radiation types) and bystander effects (particularly for low-fluence high-LET particles) and also priority should be given to confirmation, or negation, of the relevance of the processes to human health risks from radiation. Copyright 2010 Elsevier B.V. All rights reserved.

  18. Radiation risks from pediatric computed tomography scanning.

    PubMed

    Chodick, Gabriel; Kim, Kwang Pyo; Shwarz, Michael; Horev, Gad; Shalev, Varda; Ron, Elaine

    2009-12-01

    Although radiological exams are not frequently used to diagnose unsuspected endocrine disease, computed tomography (CT) plays a significant role in today's endocrinology. Despite the known association between radiation exposure during childhood and cancer, the use of pediatric CT, which delivers non-negligible radiation doses to some organs and tissues, continues to rise sharply. The purpose of this review is to describe the current use of pediatric CT, explain basic concepts in ionizing radiation physics and dosimetry, and discuss potential risks from pediatric CT scans. Finally, we will summarize two recent programs for reducing and controlling exposure to ionizing radiation from pediatric CT: the As Low As Reasonably Achievable (ALARA) concept and the Image Gently initiative. Promoting public awareness and particularly educating referring physicians, including endocrinologists, about the potential radiation-associated risks from CT scans, is essential for reducing unnecessary radiation exposure from CT in children.

  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. 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.

  1. Radiation Proctitis: Current Strategies in Management

    PubMed Central

    Do, Nhue L.; Nagle, Deborah; Poylin, Vitaliy Y.

    2011-01-01

    Radiation proctitis is a known complication following radiation therapy for pelvic malignancy. The majority of cases are treated nonsurgically, and an understanding of the available modalities is crucial in the management of these patients. In this paper, we focus on the current treatments of radiation proctitis. PMID:22144997

  2. 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)

  3. 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

  4. Radiation Hormesis: Historical and Current Perspectives.

    PubMed

    Baldwin, Jonathan; Grantham, Vesper

    2015-12-01

    The purpose of this article is to provide the reader with a better understanding of radiation hormesis, the investigational research that supports or does not support the theory, and the relationship between the theory and current radiation safety guidelines and practices. The concept of radiation hormesis is known to nuclear medicine technologists, but understanding its complexities and the historical development of the theory may bring about a better understanding of radiation safety and regulations.

  5. Very Low Dose Fetal Exposure to Chernobyl Contamination Resulted in Increases in Infant Leukemia in Europe and Raises Questions about Current Radiation Risk Models

    PubMed Central

    Busby, Christopher C.

    2009-01-01

    Following contamination from the Chernobyl accident in April 1986 excess infant leukemia (0–1 y) was reported from five different countries, Scotland, Greece, Germany, Belarus and Wales and Scotland combined. The cumulative absorbed doses to the fetus, as conventionally assessed, varied from 0.02 mSv in the UK through 0.06 mSv in Germany, 0.2 mSv in Greece and 2 mSv in Belarus, where it was highest. Nevertheless, the effect was real and given the specificity of the cohort raised questions about the safety of applying the current radiation risk model of the International Commission on Radiological Protection (ICRP) to these internal exposures, a matter which was discussed in 2000 by Busby and Cato [7,8] and also in the reports of the UK Committee examining Radiation Risk from Internal Emitters. Data on infant leukemia in the United Kingdom, chosen on the basis of the cohorts defined by the study of Greece were supplied by the UK Childhood Cancer Research Group. This has enabled a study of leukemia in the combined infant population of 15,466,845 born in the UK, Greece, and Germany between 1980 and 1990. Results show a statistically significant excess risk RR = 1.43 (95% CI 1.13 < RR < 1.80 (2-tailed); p = 0.0025) in those born during the defined peak exposure period of 01/07/86 to 31/12/87 compared with those born between 01/01/80 and 31/12/85 and 01/01/88 and 31/12/90. The excess risks in individual countries do not increase monotonically with the conventionally calculated doses, the relation being biphasic, increasing sharply at low doses and falling at high doses. This result is discussed in relation to fetal/cell death at higher doses and also to induction of DNA repair. Since the cohort is chosen specifically on the basis of exposure to internal radionuclides, the result can be expressed as evidence for a significant error in the conventional modeling for such internal fetal exposures. PMID:20049249

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  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. Radiation-induced vaginal stenosis: current perspectives

    PubMed Central

    Morris, Lucinda; Do, Viet; Chard, Jennifer; Brand, Alison H

    2017-01-01

    Treatment of gynecological cancer commonly involves pelvic radiation therapy (RT) and/or brachytherapy. A commonly observed side effect of such treatment is radiation-induced vaginal stenosis (VS). This review analyzed the incidence, pathogenesis, clinical manifestation(s) and assessment and grading of radiation-induced VS. In addition, risk factors, prevention and treatment options and follow-up schedules are also discussed. The limited available literature on many of these aspects suggests that additional studies are required to more precisely determine the best management strategy of this prevalent group after RT. PMID:28496367

  13. Determination of radiative current in LED's

    NASA Technical Reports Server (NTRS)

    Thomas, E. F.

    1976-01-01

    Directly measureable quantity of radiative output in LED's is total forward current. When applied forward voltage is below 1.05 V the forward current is primarily nonradiative and varies with forward voltage as exp(qV/2kT), when q is the charge, V is applied voltage, K is Boltzmann's constant, and T is operating temperature.

  14. Determination of radiative current in LED's

    NASA Technical Reports Server (NTRS)

    Thomas, E. F.

    1976-01-01

    Directly measureable quantity of radiative output in LED's is total forward current. When applied forward voltage is below 1.05 V the forward current is primarily nonradiative and varies with forward voltage as exp(qV/2kT), when q is the charge, V is applied voltage, K is Boltzmann's constant, and T is operating temperature.

  15. RADIATION-RELATED HEART DISEASE: CURRENT KNOWLEDGE AND FUTURE PROSPECTS

    PubMed Central

    Darby, Sarah C.; Cutter, David J.; Boerma, Marjan; Constine, Louis S.; Fajardo, Luis F.; Kodama, Kazunori; Mabuchi, Kiyo; Marks, Lawrence B.; Mettler, Fred A.; Pierce, Lori J.; Trott, Klaus R.; Yeh, Edward T.H.; Shore, Roy E.

    2014-01-01

    The heart has traditionally been considered a radio-resistant organ that would be unaffected by cardiac doses below about 30 Gray. During the last few years, however, evidence that radiation-related heart disease can occur following lower doses has emerged from several sources. These include studies of breast cancer patients, who received mean cardiac doses of 3–17 Gray when given radiotherapy following surgery, and studies of survivors of the atomic bombings of Japan who received doses of up to 4 Gray. At doses above 30 Gray, radiation-related heart disease may occur within a year or two of exposure and risk increases with higher radiotherapy dose, younger age at irradiation, and the presence of conventional risk factors. At lower doses the typical latent period is much longer and is often more than a decade. However, the nature and magnitude of the risk following lower doses is not well characterized, and it is not yet clear whether there is a threshold dose below which there is no risk. The evidence regarding radiation-related heart disease comes from several different disciplines. The present review brings together information from pathology, radiobiology, cardiology, radiation oncology and epidemiology. It summarises current knowledge, identifies gaps in that knowledge, and outlines some potential strategies for filling them. Further knowledge about the nature and magnitude of radiation-related heart disease would have immediate application in radiation oncology. It would also provide a basis for radiation protection policies for use in diagnostic radiology and occupational exposure. PMID:20159360

  16. 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

  17. Radiation protectants: current status and future prospects.

    PubMed

    Seed, Thomas M

    2005-11-01

    In today's heightened nuclear/biological/chemical threat environment, there is an increased need to have safe and effective means to protect not only special high-risk service groups, but also the general population at large, from the health hazards of unintended ionizing radiation exposures. An unfulfilled dream has been to have a globally effective pharmacologic that could be easily taken orally without any undue side effects prior to a suspected or impending nuclear/radiological event; such an ideal radioprotective agent has yet to be identified, let alone fully developed and approved for human use. No one would argue against the fact that this is problematic and needs to be corrected, but where might the ultimate solution to this difficult problem be found? Without question, representative species of the aminothiol family [e.g., Amifostine (MedImmune, Gaithersburg, Maryland)] have proven to be potent cytoprotectants for normal tissues subjected to irradiation or to radiomimetic chemicals. Although Amifostine is currently used clinically, drug toxicity, limited times of protection, and unfavorable routes of administration, all serve to limit the drug's utility in nonclinical settings. A full range of research and development strategies is being employed currently in the hunt for new safe and effective radioprotectants. These include: (1) large scale screening of new chemical classes or natural products; (2) restructuring/reformulating older protectants with proven efficacies but unwanted toxicities; (3) using nutraceuticals that are only moderately protective but are essentially nontoxic; (4) using low dose combinations of potentially toxic but efficacious agents that protect through different routes to foster radioprotective synergy; and (5) accepting a lower level of drug efficacy in lieu of reduced toxicity, banking on the premise that the protection afforded can be leveraged by post-exposure therapies. Although it is difficult to predict which of these

  18. 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

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

    PubMed

    Seong, Ki Moon; Kwon, TaeWoo; 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.

  20. Radiation Belt and Ring Current Forecasting Model

    NASA Astrophysics Data System (ADS)

    Fok, M.; Khazanov, G. V.

    2001-12-01

    A model has been developed to predict the radiation belt and ring current environment. The core of this forecasting model is a kinetic model, which solves the convection-diffusion equation of particle distributions at 10 keV to MeV energy range. This forecasting model is solely driven by the solar wind and IMF conditions. We will present the model logic, and the model validation by comparing measured particle fluxes during several magnetic storms with model calculations. In addition, we will estimate the radiation dose collected during these active periods. Finally, future development of this forecasting model will be discussed.

  1. 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.

  2. Radiation-Dominated Relativistic Current Sheets

    NASA Astrophysics Data System (ADS)

    Jaroschek, C. H.; Hoshino, M.

    2009-08-01

    Relativistic current sheets (RCSs) feature plasma instabilities considered as the potential key to magnetic energy dissipation in Poynting-flux-dominated plasma flows. Kinetic plasma simulations show that the physical nature of RCS evolution changes in the presence of radiation losses: In the ultrarelativistic regime (i.e., magnetization parameter σ=104 defined as the ratio of magnetic to plasma rest frame energy density), the combined effect of nonlinear RCS dynamics and synchrotron emission introduces a temperature anisotropy triggering the growth of the relativistic tearing mode. In contrast to previous studies of the RCS with σ˜1, the relativistic tearing mode then prevails over the drift kink mode. The ultrarelativistic RCS shows a typical life cycle from radiation-induced collapse towards a radiation-quiescent phase with topology analogous to that introduced by Sweet and Parker.

  3. Radiation Effects on Current Field Programmable Technologies

    NASA Technical Reports Server (NTRS)

    Katz, R.; LaBel, K.; Wang, J. J.; Cronquist, B.; Koga, R.; Penzin, S.; Swift, G.

    1997-01-01

    Manufacturers of field programmable gate arrays (FPGAS) take different technological and architectural approaches that directly affect radiation performance. Similar y technological and architectural features are used in related technologies such as programmable substrates and quick-turn application specific integrated circuits (ASICs). After analyzing current technologies and architectures and their radiation-effects implications, this paper includes extensive test data quantifying various devices total dose and single event susceptibilities, including performance degradation effects and temporary or permanent re-configuration faults. Test results will concentrate on recent technologies being used in space flight electronic systems and those being developed for use in the near term. This paper will provide the first extensive study of various configuration memories used in programmable devices. Radiation performance limits and their impacts will be discussed for each design. In addition, the interplay between device scaling, process, bias voltage, design, and architecture will be explored. Lastly, areas of ongoing research will be discussed.

  4. Radiation effects on current field programmable technologies

    NASA Astrophysics Data System (ADS)

    Katz, R.; LaBel, K.; Wang, J. J.; Cronquist, B.; Koga, R.; Penzin, S.; Swift, G.

    1997-12-01

    Manufacturers of field programmable gate arrays (FPGAs) take different technological and architectural approaches that directly affect radiation performance. Similar technological and architectural features are used in related technologies such as programmable substrates and quick-turn application specific integrated circuits (ASICs). After analyzing current technologies and architectures and their radiation-effects implications, this paper includes extensive test data quantifying various devices' total dose and single event susceptibilities, including performance degradation effects and temporary or permanent re-configuration faults. Test results will concentrate on recent technologies being used in space flight electronic systems and those being developed for use in the near term. This paper will provide the first extensive study of various configuration memories used in programmable devices. Radiation performance limits and their impacts will be discussed for each design. In addition, the interplay between device scaling, process, bias voltage, design, and architecture will be explored. Lastly, areas of ongoing research will be discussed.

  5. 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.

  6. 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%.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. Current issues and actions in radiation protection of patients.

    PubMed

    Holmberg, Ola; Malone, Jim; Rehani, Madan; McLean, Donald; Czarwinski, Renate

    2010-10-01

    Medical application of ionizing radiation is a massive and increasing activity globally. While the use of ionizing radiation in medicine brings tremendous benefits to the global population, the associated risks due to stochastic and deterministic effects make it necessary to protect patients from potential harm. Current issues in radiation protection of patients include not only the rapidly increasing collective dose to the global population from medical exposure, but also that a substantial percentage of diagnostic imaging examinations are unnecessary, and the cumulative dose to individuals from medical exposure is growing. In addition to this, continued reports on deterministic injuries from safety related events in the medical use of ionizing radiation are raising awareness on the necessity for accident prevention measures. The International Atomic Energy Agency is engaged in several activities to reverse the negative trends of these current issues, including improvement of the justification process, the tracking of radiation history of individual patients, shared learning of safety significant events, and the use of comprehensive quality audits in the clinical environment. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  13. 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.

  14. 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

  15. 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.

  16. Current Chemical Risk Reduction Activities

    EPA Pesticide Factsheets

    EPA's existing chemicals programs address pollution prevention, risk assessment, hazard and exposure assessment and/or characterization, and risk management for chemicals substances in commercial use.

  17. RADIATING CURRENT SHEETS IN THE SOLAR CHROMOSPHERE

    SciTech Connect

    Goodman, Michael L.; Judge, Philip G. E-mail: judge@ucar.edu

    2012-05-20

    An MHD model of a hydrogen plasma with flow, an energy equation, NLTE ionization and radiative cooling, and an Ohm's law with anisotropic electrical conduction and thermoelectric effects is used to self-consistently generate atmospheric layers over a 50 km height range. A subset of these solutions contains current sheets and has properties similar to those of the lower and middle chromosphere. The magnetic field profiles are found to be close to Harris sheet profiles, with maximum field strengths {approx}25-150 G. The radiative flux F{sub R} emitted by individual sheets is {approx}4.9 Multiplication-Sign 10{sup 5}-4.5 Multiplication-Sign 10{sup 6} erg cm{sup -2} s{sup -1}, to be compared with the observed chromospheric emission rate of {approx}10{sup 7} erg cm{sup -2} s{sup -1}. Essentially all emission is from regions with thicknesses {approx}0.5-13 km containing the neutral sheet. About half of F{sub R} comes from sub-regions with thicknesses 10 times smaller. A resolution {approx}< 5-130 m is needed to resolve the properties of the sheets. The sheets have total H densities {approx}10{sup 13}-10{sup 15} cm{sup -3}. The ionization fraction in the sheets is {approx}2-20 times larger, and the temperature is {approx}2000-3000 K higher than in the surrounding plasma. The Joule heating flux F{sub J} exceeds F{sub R} by {approx}4%-34%, the difference being balanced in the energy equation mainly by a negative compressive heating flux. Proton Pedersen current dissipation generates {approx}62%-77% of the positive contribution to F{sub J} . The remainder of this contribution is due to electron current dissipation near the neutral sheet where the plasma is weakly magnetized.

  18. Bubble Radiation Detection: Current and Future Capability

    SciTech Connect

    AJ Peurrung; RA Craig

    1999-11-15

    Despite a number of noteworthy achievements in other fields, superheated droplet detectors (SDDs) and bubble chambers (BCs) have not been used for nuclear nonproliferation and arms control. This report examines these two radiation-detection technologies in detail and answers the question of how they can be or should be ''adapted'' for use in national security applications. These technologies involve closely related approaches to radiation detection in which an energetic charged particle deposits sufficient energy to initiate the process of bubble nucleation in a superheated fluid. These detectors offer complete gamma-ray insensitivity when used to detect neutrons. They also provide controllable neutron-energy thresholds and excellent position resolution. SDDs are extraordinarily simple and inexpensive. BCs offer the promise of very high efficiency ({approximately}75%). A notable drawback for both technologies is temperature sensitivity. As a result of this problem, the temperature must be controlled whenever high accuracy is required, or harsh environmental conditions are encountered. The primary findings of this work are listed and briefly summarized below: (1) SDDs are ready to function as electronics-free neutron detectors on demand for arms-control applications. The elimination of electronics at the weapon's location greatly eases the negotiability of radiation-detection technologies in general. (2) As a result of their high efficiency and sharp energy threshold, current BCs are almost ready for use in the development of a next-generation active assay system. Development of an instrument based on appropriately safe materials is warranted. (3) Both kinds of bubble detectors are ready for use whenever very high gamma-ray fields must be confronted. Spent fuel MPC and A is a good example where this need presents itself. (4) Both kinds of bubble detectors have the potential to function as low-cost replacements for conventional neutron detectors such as {sup 3}He

  19. 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

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  4. [Therapy of radiation enteritis--current challenges].

    PubMed

    Baranyai, Zsolt; Sinkó, Dániel; Jósa, Valéria; Zaránd, Attila; Teknos, Dániel

    2011-07-10

    Radiation enteritis is one of the most feared complications after abdominal and pelvic radiation therapy. The incidence varies from 0.5 to 5%. It is not rare that the slowly progressing condition will be fatal. During a period of 13 years 24 patients were operated due to the complication of radiation enteritis. Despite different types of surgery repeated operation was required in 25% of cases and finally 4 patients died. Analyzing these cases predisposing factors and different therapeutic options of this condition are discussed. Treatment options of radiation induced enteritis are limited; however, targeted therapy significantly improves the outcome. Cooperation between oncologist, gastroenterologist and surgeon is required to establish adequate therapeutic plan.

  5. 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.

  6. 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.

  7. Radiation and cancer risk: a continuing challenge for epidemiologists

    PubMed Central

    2011-01-01

    This paper provides a perspective on epidemiological research on radiation and cancer, a field that has evolved over its six decade history. The review covers the current framework for assessing radiation risk and persistent questions about the details of these risks: is there a threshold and more generally, what is the shape of the dose-response relationship? How do risks vary over time and with age? What factors modify the risk of radiation? The example of radon progeny and lung cancer is considered as a case study, illustrating the modeling of epidemiological data to derive quantitative models and the coherence of the epidemiological and biological evidence. Finally, the manuscript considers the need for ongoing research, even in the face of research over a 60-year span. PMID:21489214

  8. 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.

  9. Benzene risk estimation using radiation equivalent coefficients.

    PubMed

    Nakayama, Aki; Isono, Tomomi; Kikuchi, Takuro; Ohnishi, Iichiro; Igarashi, Junichiro; Yoneda, Minoru; Morisawa, Shinsuke

    2009-03-01

    We estimated benzene risk using a novel framework of risk assessment that employed the measurement of radiation dose equivalents to benzene metabolites and a PBPK model. The highest risks for 1 microg/m(3) and 3.2 mg/m(3) life time exposure of benzene estimated with a linear regression were 5.4 x 10(-7) and 1.3 x 10(-3), respectively. Even though these estimates were based on in vitro chromosome aberration test data, they were about one-sixth to one-fourteenth that from other studies and represent a fairly good estimate by using radiation equivalent coefficient as an "internal standard."

  10. Current trends in nuclear and radiation sensing

    NASA Astrophysics Data System (ADS)

    McHugh, Harold R.; Quam, William

    2009-05-01

    This paper provides a brief overview of radiation detector history, a summary of the present state of the art, and some speculation on future developments in this field. Trends in the development of radiation detectors over the years are analyzed. Rapid progress in detection technology was experienced between WWII and the 1970s. Since then, fewer dramatic improvements have been seen. The authors speculate about the reasons for this trend and where the technology might take us in the next 20 years. Requirements for radiation detection equipment have changed drastically since 9/11; this demand is likely to accelerate detector development in the near future.

  11. [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.

  12. Radiation Metabolomics: Current Status and Future Directions

    PubMed Central

    Menon, Smrithi S.; Uppal, Medha; Randhawa, Subeena; Cheema, Mehar S.; Aghdam, Nima; Usala, Rachel L.; Ghosh, Sanchita P.; Cheema, Amrita K.; Dritschilo, Anatoly

    2016-01-01

    Human exposure to ionizing radiation (IR) disrupts normal metabolic processes in cells and organs by inducing complex biological responses that interfere with gene and protein expression. Conventional dosimetry, monitoring of prodromal symptoms, and peripheral lymphocyte counts are of limited value as organ- and tissue-specific biomarkers for personnel exposed to radiation, particularly, weeks or months after exposure. Analysis of metabolites generated in known stress-responsive pathways by molecular profiling helps to predict the physiological status of an individual in response to environmental or genetic perturbations. Thus, a multi-metabolite profile obtained from a high-resolution mass spectrometry-based metabolomics platform offers potential for identification of robust biomarkers to predict radiation toxicity of organs and tissues resulting from exposures to therapeutic or non-therapeutic IR. Here, we review the status of radiation metabolomics and explore applications as a standalone technology, as well as its integration in systems biology, to facilitate a better understanding of the molecular basis of radiation response. Finally, we draw attention to the identification of specific pathways that can be targeted for the development of therapeutics to alleviate or mitigate harmful effects of radiation exposure. PMID:26870697

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Radiation risk management at DOE accelerator facilities

    SciTech Connect

    Dyck, O.B. van

    1997-01-01

    The DOE accelerator contractors have been discussing among themselves and with the Department how to improve radiation safety risk management. This activity-how to assure prevention of unplanned high exposures-is separate from normal exposure management, which historically has been quite successful. The ad-hoc Committee on the Accelerator Safety Order and Guidance [CASOG], formed by the Accelerator Section of the HPS, has proposed a risk- based approach, which will be discussed. Concepts involved are risk quantification and comparison (including with non-radiation risk), passive and active (reacting) protection systems, and probabilistic analysis. Different models of risk management will be presented, and the changing regulatory environment will also be discussed..

  18. [Risks related to radiation therapy].

    PubMed

    Bey, Pierre

    2015-01-01

    Radiotherapy is used for about 60% of cancer patients, in 2/3rd of the cases with a curative intent. If the frequent early secondary effects are transitory and with a limited impact, some late effects, even rare as cardiac troubles and secondary tumors, are now more important due to the increase of cure rate and due to the improvement of life expectancy of cured patients. Technologic improvements of the last decades reduced some of these risks, as the strengthening of human resources and the development of quality assurance procedures have contributed to reduce the risk of major accidents.

  19. Radiation risk during long-term spaceflight.

    PubMed

    Petrov, V M

    2002-01-01

    Cosmonauts' exposure to cosmic rays during long-term spaceflight can cause unfavorable effects in health and risk for the crew members' lives. All unfavorable effects induced by exposure should be taken into consideration for the risk estimation. They should include both the acute deterministic effects and delayed effects called stochastic. On the ground the limitation of unfavorable consequences of acute exposure is achieved by means of establishing dose limits. But in space applications this approach can't be acceptable. Establishing a fixed dose limit is adequate to introducing indefinite reserve coefficient and therefore ineffective usage of spacecraft resource. The method of radiation risk calculation caused by acute and delayed effects of cosmonauts' exposure is discussed and substantiated in the report. Peculiarities of the impact of permanent radiation sources (galactic cosmic rays and trapped radiation) and the variable one (solar cosmic rays) are taken into consideration. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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."

  8. 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.

  9. 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

  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.

    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

  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.; 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

  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.

    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

  13. 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

  14. 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

  15. Current status of liquid sheet radiator research

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Calfo, Frederick D.; Mcmaster, Matthew S.

    1993-01-01

    Initial research on the external flow, low mass liquid sheet radiator (LSR), has been concentrated on understanding its fluid mechanics. The surface tension forces acting at the edges of the sheet produce a triangular planform for the radiating surface of width, W, and length, L. It has been experimentally verified that (exp L)/W agrees with the theoretical result, L/W = (We/8)exp 1/2, where We is the Weber number. Instability can cause holes to form in regions of large curvature such as where the edge cylinders join the sheet of thickness, tau. The W/tau limit that will cause hole formation with subsequent destruction of the sheet has yet to be reached experimentally. Although experimental measurements of sheet emissivity have not yet been performed because of limited program scope, calculations of the emissivity and sheet lifetime is determined by evaporation losses were made for two silicon based oils; Dow Corning 705 and Me(sub 2). Emissivities greater than 0.75 are calculated for tau greater than or equal to 200 microns for both oils. Lifetimes for Me(sub 2) are much longer than lifetimes for 705. Therefore, Me(sub 2) is the more attractive working fluid for higher temperatures (T greater than or equal to 400 K).

  16. Current status of liquid sheet radiator research

    NASA Astrophysics Data System (ADS)

    Chubb, Donald L.; Calfo, Frederick D.; McMaster, Matthew S.

    1993-01-01

    Initial research on the external flow, low mass liquid sheet radiator (LSR), has been concentrated on understanding its fluid mechanics. The surface tension forces acting at the edges of the sheet produce a triangular planform for the radiating surface of width, W, and length, L. It has been experimentally verified that (exp L)/W agrees with the theoretical result, L/W = (We/8)exp 1/2, where We is the Weber number. Instability can cause holes to form in regions of large curvature such as where the edge cylinders join the sheet of thickness, tau. The W/tau limit that will cause hole formation with subsequent destruction of the sheet has yet to be reached experimentally. Although experimental measurements of sheet emissivity have not yet been performed because of limited program scope, calculations of the emissivity and sheet lifetime is determined by evaporation losses were made for two silicon based oils; Dow Corning 705 and Me(sub 2). Emissivities greater than 0.75 are calculated for tau greater than or equal to 200 microns for both oils. Lifetimes for Me(sub 2) are much longer than lifetimes for 705. Therefore, Me(sub 2) is the more attractive working fluid for higher temperatures (T greater than or equal to 400 K).

  17. 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.

  18. 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.

  19. 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.

  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. 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.

  2. Cancer risks after radiation exposure in middle age.

    PubMed

    Shuryak, Igor; Sachs, Rainer K; Brenner, David J

    2010-11-03

    Epidemiological data show that radiation exposure during childhood is associated with larger cancer risks compared with exposure at older ages. For exposures in adulthood, however, the relative risks of radiation-induced cancer in Japanese atomic bomb survivors generally do not decrease monotonically with increasing age of adult exposure. These observations are inconsistent with most standard models of radiation-induced cancer, which predict that relative risks decrease monotonically with increasing age at exposure, at all ages. We analyzed observed cancer risk patterns as a function of age at exposure in Japanese atomic bomb survivors by using a biologically based quantitative model of radiation carcinogenesis that incorporates both radiation induction of premalignant cells (initiation) and radiation-induced promotion of premalignant damage. This approach emphasizes the kinetics of radiation-induced initiation and promotion, and tracks the yields of premalignant cells before, during, shortly after, and long after radiation exposure. Radiation risks after exposure in younger individuals are dominated by initiation processes, whereas radiation risks after exposure at later ages are more influenced by promotion of preexisting premalignant cells. Thus, the cancer site-dependent balance between initiation and promotion determines the dependence of cancer risk on age at radiation exposure. For example, in terms of radiation induction of premalignant cells, a quantitative measure of the relative contribution of initiation vs promotion is 10-fold larger for breast cancer than for lung cancer. Reflecting this difference, radiation-induced breast cancer risks decrease with age at exposure at all ages, whereas radiation-induced lung cancer risks do not. For radiation exposure in middle age, most radiation-induced cancer risks do not, as often assumed, decrease with increasing age at exposure. This observation suggests that promotional processes in radiation carcinogenesis

  3. Radiation Risk to the Fluoroscopy Operator and Staff.

    PubMed

    Stahl, Cosette M; Meisinger, Quinn C; Andre, Michael P; Kinney, Thomas B; Newton, Isabel G

    2016-10-01

    Recent articles discussing cases of brain cancer in interventionalists have raised concerns regarding the hazards of occupational exposure to ionizing radiation. We review the basics of radiation dose and the potential radiation effects, particularly as they pertain to the operator. Then we present the data regarding the risk of each type of radiation effect to the fluoroscopy operator and staff, with special attention on cancer induction, radiation-induced cataracts, and the pregnant operator. Although the evidence overwhelmingly shows that exposure to higher doses of radiation carries a risk of cancer and tissue reactions, the risks of chronic exposure to low-level radiation are less clear. Many studies examining occupational exposure to radiation fail to show an increased risk of stochastic effects of radiation, but the positive results raise concern that the studies are underpowered to consistently detect the small risk. The lack of information in these studies about radiation doses and adherence to radiation protection further confound their interpretation. Large prospective studies of populations with occupational exposure to low-level radiation might clarify this issue. More clearly established are the risks of radiation to the fetus and the risk of cataracts in interventional cardiologists and interventional radiologists. Interventionalists can mitigate these risks by following established radiation safety practices.

  4. Apparatuses and method for converting electromagnetic radiation to direct current

    DOEpatents

    Kotter, Dale K; Novack, Steven D

    2014-09-30

    An energy conversion device may include a first antenna and a second antenna configured to generate an AC current responsive to incident radiation, at least one stripline, and a rectifier coupled with the at least one stripline along a length of the at least one stripline. An energy conversion device may also include an array of nanoantennas configured to generate an AC current in response to receiving incident radiation. Each nanoantenna of the array includes a pair of resonant elements, and a shared rectifier operably coupled to the pair of resonant elements, the shared rectifier configured to convert the AC current to a DC current. The energy conversion device may further include a bus structure operably coupled with the array of nanoantennas and configured to receive the DC current from the array of nanoantennas and transmit the DC current away from the array of nanoantennas.

  5. Radiation risks: what is to be done?

    PubMed

    Huda, Walter

    2015-01-01

    What is currently known about radiologic risks is reviewed, policies that should be adopted based on our current knowledge are proposed, and how these policies can be applied to adequately protect patients in everyday clinical practice is described. All activities in life (e.g., driving automobiles) are associated with risks, and medical imaging is no different, so the most important message to convey to patients is whether a proposed examination is worthwhile. Our collective goal should be ensuring that all radiologic examinations are justified and are as low as reasonably achievable (ALARA), which maximizes the benefits of medical imaging for our patients.

  6. 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.

  7. Uncertainties in Projecting Risks of Late Effects from Space Radiation

    NASA Astrophysics Data System (ADS)

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

    The health risks faced by astronauts from space radiation include cancer, cataracts, hereditary effects, CNS risks, 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 the primary 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 objectives, i.e., number of days in space without exceeding a given risk level within well defined confidence limits

  8. 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

  9. Higher-spin currents and thermal flux from Hawking radiation

    SciTech Connect

    Iso, Satoshi; Morita, Takeshi; Umetsu, Hiroshi

    2007-06-15

    Quantum fields near black hole horizons can be described in terms of an infinite set of d=2 conformal fields. In this paper, by investigating transformation properties of general higher-spin currents under a conformal transformation, we reproduce the thermal distribution of Hawking radiation in both cases of bosons and fermions. As a by-product, we obtain a generalization of the Schwarzian derivative for higher-spin currents.

  10. Radiation from a current filament driven by a traveling wave

    NASA Technical Reports Server (NTRS)

    Levine, D. M.; Meneghini, R.

    1976-01-01

    Solutions are presented for the electromagnetic fields radiated by an arbitrarily oriented current filament located above a perfectly conducting ground plane and excited by a traveling current wave. Both an approximate solution, valid in the fraunhofer region of the filament and predicting the radiation terms in the fields, and an exact solution, which predicts both near and far field components of the electromagnetic fields, are presented. Both solutions apply to current waveforms which propagate along the channel but are valid regardless of the actual waveshape. The exact solution is valid only for waves which propagate at the speed of light, and the approximate solution is formulated for arbitrary velocity of propagation. The spectrum-magnitude of the fourier transform-of the radiated fields is computed by assuming a compound exponential model for the current waveform. The effects of channel orientation and length, as well as velocity of propagation of the current waveform and location of the observer, are discussed. It is shown that both velocity of propagation and an effective channel length are important in determining the shape of the spectrum.

  11. A radiating one-dimensional current sheet configuration

    NASA Technical Reports Server (NTRS)

    Pritchett, P. L.; Coroniti, F. V.

    1993-01-01

    The structure of the x-independent (one-dimensional) forced current sheet including a self consistent By component is investigated for the case of small normal field component, Bz/B0 much less than 1. A hybrid (kinetic ions, massless fluid electrons) simulation model is used to demonstrate that such a current sheet has a time-dependent structure which radiates incompressible Alfven waves with amplitude of the order of the asymptotic (lobe) field strength B0. The central density enhancement acts as the source of a propagating wavetrain in which Bx rotates into By and back again. One of the characteristic signatures of the radiating current sheet is the presence of a reversal in Bx (or By) without a corresponding increase in density.

  12. Spontaneous Smith-Purcell radiation described through induced surface currents

    NASA Astrophysics Data System (ADS)

    Brownell, J. H.; Walsh, J.; Doucas, G.

    1998-01-01

    An analytic solution for the radiated intensity distribution produced by an electron beam passing over a metallic diffraction grating (the Smith-Purcell effect) is derived. The approach is based upon an expression for the current traveling over the grating surface and the method can deal with arbitrary grating profiles. Although collective behavior in the electron beam is neglected, very high power density is predicted if high energy, short electron bunches are employed. The electron beam characteristics of various accelerators are used to illustrate the potential of high energy, accelerator based Smith-Purcell radiation sources.

  13. Monitoring cystic fibrosis lung disease by computed tomography. Radiation risk in perspective.

    PubMed

    Kuo, Wieying; Ciet, Pierluigi; Tiddens, Harm A W M; Zhang, Wei; Guillerman, R Paul; van Straten, Marcel

    2014-06-01

    Computed tomography (CT) is a sensitive technique to monitor structural changes related to cystic fibrosis (CF) lung disease. It detects structural pulmonary abnormalities such as bronchiectasis and trapped air, at an early stage, before they become apparent with other diagnostic tests. Clinical decisions may be influenced by knowledge of these abnormalities. CT imaging, however, comes with risk related to ionizing radiation exposure. The aim of this review is to discuss the risk of routine CT imaging in patients with CF, using current models of radiation-induced cancer, and to put this risk in perspective with other medical and nonmedical risks. The magnitude of the risk is a complex, controversial matter. Risk analyses have largely been based on a linear no-threshold model, and excess relative and excess absolute risk estimates have been derived mainly from atomic bomb survivors. The estimates have large confidence intervals. Our risk estimates are in concordance with previously reported estimates. A large proportion of radiation to which humans are exposed is from natural background sources and varies widely depending on geographical location. The risk differences due to variation in background radiation can be larger than the risks associated with CF lung disease monitoring by CT. We conclude that the risk related to routine usage of CT in clinical care is small. In addition, a life-limiting disease, such as CF, lowers the risk of radiation-induced cancer. Nonetheless, the use of CT should always be justified and the radiation dose should be kept as low as reasonably achievable.

  14. 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.

  15. 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.

  16. 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.

  17. Modeling the Inner Magnetosphere: Radiation Belts, Ring Current, and Composition

    NASA Technical Reports Server (NTRS)

    Glocer, Alex

    2011-01-01

    The space environment is a complex system defined by regions of differing length scales, characteristic energies, and physical processes. It is often difficult, or impossible, to treat all aspects of the space environment relative to a particular problem with a single model. In our studies, we utilize several models working in tandem to examine this highly interconnected system. The methodology and results will be presented for three focused topics: 1) Rapid radiation belt electron enhancements, 2) Ring current study of Energetic Neutral Atoms (ENAs), Dst, and plasma composition, and 3) Examination of the outflow of ionospheric ions. In the first study, we use a coupled MHD magnetosphere - kinetic radiation belt model to explain recent Akebono/RDM observations of greater than 2.5 MeV radiation belt electron enhancements occurring on timescales of less than a few hours. In the second study, we present initial results of a ring current study using a newly coupled kinetic ring current model with an MHD magnetosphere model. Results of a dst study for four geomagnetic events are shown. Moreover, direct comparison with TWINS ENA images are used to infer the role that composition plays in the ring current. In the final study, we directly model the transport of plasma from the ionosphere to the magnetosphere. We especially focus on the role of photoelectrons and and wave-particle interactions. The modeling methodology for each of these studies will be detailed along with the results.

  18. Current status of low-temperature radiator thermophotovoltaic devices

    SciTech Connect

    Charache, G.W.; Egley, J.L.; Danielson, L.R.; DePoy, D.M.; Baldasaro, P.F.; Campbell, B.C.; Hui, S.; Fraas, L.M.; Wojtczuk, S.J.

    1996-05-01

    The current performance status of low-temperature radiator (< 1,000 C) thermophotovoltaic (TPV) devices is presented. For low-temperature radiators, both power density and efficiency are equally important in designing an effective TPV system. Comparisons of 1 cm x 1 cm, 0.55 eV InGaAs and InGaAsSb voltaic devices are presented. Currently, InGaAs lattice-mismatched devices offer superior performance in comparison to InGaAsSb lattice-matched devices, due to the former`s long-term development for numerous optoelectronic applications. However, lattice-matched antimony-based quaternaries offer numerous potential advantages.

  19. HAMLET -Human Model MATROSHKA for Radiation Exposure Determination of Astronauts -Current status and results

    NASA Astrophysics Data System (ADS)

    Reitz, Guenther; Berger, Thomas; Bilski, Pawel; Burmeister, Soenke; Labrenz, Johannes; Hager, Luke; Palfalvi, Jozsef K.; Hajek, Michael; Puchalska, Monika; Sihver, Lembit

    The exploration of space as seen in specific projects from the European Space Agency (ESA) acts as groundwork for human long duration space missions. One of the main constraints for long duration human missions is radiation. The radiation load on astronauts and cosmonauts in space (as for the ISS) is a factor of 100 higher than the natural radiation on Earth and will further increase should humans travel to Mars. In preparation for long duration space missions it is important to evaluate the impact of space radiation in order to secure the safety of the astronauts and minimize their radiation risks. To determine the radiation risk on humans one has to measure the radiation doses to radiosensitive organs within the human body. One way to approach this is the ESA facility MATROSHKA (MTR), under the scientific and project lead of DLR. It is dedicated to determining the radiation load on astronauts within and outside the International Space Station (ISS), and was launched in January 2004. MTR is currently preparing for its fourth experimental phase inside the Japanese Experimental Module (JEM) in summer 2010. MTR, which mimics a human head and torso, is an anthropomorphic phantom containing over 6000 radiation detectors to determine the depth dose and organ dose distribution in the body. It is the largest international research initiative ever performed in the field of space dosimetry and combines the expertise of leading research institutions around the world, thereby generating a huge pool of data of potentially immense value for research. Aiming at optimal scientific exploitation, the FP7 project HAMLET aims to process and compile the data acquired individually by the participating laboratories of the MATROSHKA experiment. Based on experimental input from the MATROSHKA experiment phases as well as on radiation transport calculations, a three-dimensional model for the distribution of radiation dose in an astronaut's body will be built up. The scientific achievements

  20. 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

  1. 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

  2. [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.

  3. 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.

  4. 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.

  5. Minimizing Astronauts' Risk from Space Radiation during Future Lunar Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Hayat, Mathew; Nounu, Hatem N.; Feiveson, Alan H.; Cucinotta, Francis A.

    2007-01-01

    This viewgraph presentation reviews the risk factors from space radiation for astronauts on future lunar missions. Two types of radiation are discussed, Galactic Cosmic Radiation (GCR) and Solar Particle events (SPE). Distributions of Dose from 1972 SPE at 4 DLOCs inside Spacecraft are shown. A chart with the organ dose quantities is also given. Designs of the exploration class spacecraft and the planned lunar rover are shown to exhibit radiation protections features of those vehicles.

  6. Mitigating the risk of radiation-induced cancers: limitations and paradigms in drug development.

    PubMed

    Yoo, Stephen S; Jorgensen, Timothy J; Kennedy, Ann R; Boice, John D; Shapiro, Alla; Hu, Tom C-C; Moyer, Brian R; Grace, Marcy B; Kelloff, Gary J; Fenech, Michael; Prasanna, Pataje G S; Coleman, C Norman

    2014-06-01

    The United States radiation medical countermeasures (MCM) programme for radiological and nuclear incidents has been focusing on developing mitigators for the acute radiation syndrome (ARS) and delayed effects of acute radiation exposure (DEARE), and biodosimetry technologies to provide radiation dose assessments for guiding treatment. Because a nuclear accident or terrorist incident could potentially expose a large number of people to low to moderate doses of ionising radiation, and thus increase their excess lifetime cancer risk, there is an interest in developing mitigators for this purpose. This article discusses the current status, issues, and challenges regarding development of mitigators against radiation-induced cancers. The challenges of developing mitigators for ARS include: the long latency between exposure and cancer manifestation, limitations of animal models, potential side effects of the mitigator itself, potential need for long-term use, the complexity of human trials to demonstrate effectiveness, and statistical power constraints for measuring health risks (and reduction of health risks after mitigation) following relatively low radiation doses (<0.75 Gy). Nevertheless, progress in the understanding of the molecular mechanisms resulting in radiation injury, along with parallel progress in dose assessment technologies, make this an opportune, if not critical, time to invest in research strategies that result in the development of agents to lower the risk of radiation-induced cancers for populations that survive a significant radiation exposure incident.

  7. 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

  8. 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.

  9. Estimation of radiation cancer risk in CT-KUB

    NASA Astrophysics Data System (ADS)

    Karim, M. K. A.; Hashim, S.; Bakar, K. A.; Bradley, D. A.; Ang, W. C.; Bahrudin, N. A.; Mhareb, M. H. A.

    2017-08-01

    The increased demand for computed tomography (CT) in radiological scanning examinations raises the question of a potential health impact from the associated radiation exposures. Focusing on CT kidney-ureter-bladder (CT-KUB) procedures, this work was aimed at determining organ equivalent dose using a commercial CT dose calculator and providing an estimate of cancer risks. The study, which included 64 patients (32 males and 32 females, mean age 55.5 years and age range 30-80 years), involved use of a calibrated CT scanner (Siemens-Somatom Emotion 16-slice). The CT exposures parameter including tube potential, pitch factor, tube current, volume CT dose index (CTDIvol) and dose-length product (DLP) were recorded and analyzed using CT-EXPO (Version 2.3.1, Germany). Patient organ doses, including for stomach, liver, colon, bladder, red bone marrow, prostate and ovaries were calculated and converted into cancer risks using age- and sex-specific data published in the Biological Effects of Ionizing Radiation (BEIR) VII report. With a median value scan range of 36.1 cm, the CTDIvol, DLP, and effective dose were found to be 10.7 mGy, 390.3 mGy cm and 6.2 mSv, respectively. The mean cancer risks for males and females were estimated to be respectively 25 and 46 out of 100,000 procedures with effective doses between 4.2 mSv and 10.1 mSv. Given the increased cancer risks from current CT-KUB procedures compared to conventional examinations, we propose that the low dose protocols for unenhanced CT procedures be taken into consideration before establishing imaging protocols for CT-KUB.

  10. 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.

  11. Current experience on calibration of radiators in Cuba

    NASA Astrophysics Data System (ADS)

    Miranda, J. Fernandez

    This paper describes the experience acquired in calibration of three types of laboratory radiators installed in Cuba: the SINGLE-CELL-RAILSYSTEM, the GAMMA-CELL-500-001 and MRX-GAMMA-25M. The first two were made by Atomic Energy of Canada, Ltd. (AECL) in 1957 and 1984, respectively, and the last in 1971 in the USSR. All three incorporate a cobalt-60 source with different nominal activities and technical characteristic. During the dosimetric calibrations, these characteristics were studied on the basis of parameters, such as dose rate, intercept, uniformity ratio and tolerance limits. Fricke and Ceric sulfate dosimeters were used to perform the measurements. Statistical aspects of dose evaluation and its distribution were also considered. The accuracy of the results enable us to increase the efficacy in utilization of these radiators in the applications for which they are currently used.

  12. Cancer risks attributable to low doses of ionizing radiation: assessing what we really know.

    PubMed

    Brenner, David J; Doll, Richard; Goodhead, Dudley T; Hall, Eric J; Land, Charles E; Little, John B; Lubin, Jay H; Preston, Dale L; Preston, R Julian; Puskin, Jerome S; Ron, Elaine; Sachs, Rainer K; Samet, Jonathan M; Setlow, Richard B; Zaider, Marco

    2003-11-25

    High doses of ionizing radiation clearly produce deleterious consequences in humans, including, but not exclusively, cancer induction. At very low radiation doses the situation is much less clear, but the risks of low-dose radiation are of societal importance in relation to issues as varied as screening tests for cancer, the future of nuclear power, occupational radiation exposure, frequent-flyer risks, manned space exploration, and radiological terrorism. We review the difficulties involved in quantifying the risks of low-dose radiation and address two specific questions. First, what is the lowest dose of x- or gamma-radiation for which good evidence exists of increased cancer risks in humans? The epidemiological data suggest that it is approximately 10-50 mSv for an acute exposure and approximately 50-100 mSv for a protracted exposure. Second, what is the most appropriate way to extrapolate such cancer risk estimates to still lower doses? Given that it is supported by experimentally grounded, quantifiable, biophysical arguments, a linear extrapolation of cancer risks from intermediate to very low doses currently appears to be the most appropriate methodology. This linearity assumption is not necessarily the most conservative approach, and it is likely that it will result in an underestimate of some radiation-induced cancer risks and an overestimate of others.

  13. 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.

  14. Radiation induced leakage current and stress induced leakage current in ultra-thin gate oxides

    SciTech Connect

    Ceschia, M.; Paccagnella, A. |; Cester, A.; Scarpa, A.; Ghidini, G.

    1998-12-01

    Low-field leakage current has been measured in thin oxides after exposure to ionizing radiation. This Radiation Induced Leakage Current (RILC) can be described as an inelastic tunneling process mediated by neutral traps in the oxide, with an energy loss of about 1 eV. The neutral trap distribution is influenced by the oxide field applied during irradiation, thus indicating that the precursors of the neutral defects are charged, likely being defects associated to trapped holes. The maximum leakage current is found under zero-field condition during irradiation, and it rapidly decreases as the field is enhanced, due to a displacement of the defect distribution across the oxide towards the cathodic interface. The RILC kinetics are linear with the cumulative dose, in contrast with the power law found on electrically stressed devices.

  15. 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.

  16. Risk of second cancers in the era of modern radiation therapy: does the risk/benefit analysis overcome theoretical models?

    PubMed

    Chargari, Cyrus; Goodman, Karyn A; Diallo, Ibrahima; Guy, Jean-Baptiste; Rancoule, Chloe; Cosset, Jean-Marc; Deutsch, Eric; Magne, Nicolas

    2016-06-01

    In the era of modern radiation therapy, the compromise between the reductions in deterministic radiation-induced toxicities through highly conformal devices may be impacting the stochastic risk of second malignancies. We reviewed the clinical literature and evolving theoretical models evaluating the impact of intensity-modulated radiation therapy (IMRT) on the risk of second cancers, as a consequence of the increase in volumes of normal tissues receiving low doses. The risk increase (if any) is not as high as theoretical models have predicted in adults. Moreover, the increase in out-of-field radiation doses with IMRT could be counterbalanced by the decrease in volumes receiving high doses. Clinical studies with short follow-up have not corroborated the hypothesis that IMRT would drastically increase the incidence of second cancers. In children, the risk of radiation-induced carcinogenesis increases from low doses and consequently the relative risk of second cancers after IMRT could be higher than in adults, justifying current developments of proton therapy with priority given to this population. Although only longer follow-up will allow a true assessment of the real impact of these modern techniques on radiation-induced carcinogenesis, a comprehensive risk-adapted strategy will help minimize the probability of second cancers.

  17. Radiation Hormesis: Historical Perspective and Implications for Low-Dose Cancer Risk Assessment

    PubMed Central

    Vaiserman, Alexander M.

    2010-01-01

    Current guidelines for limiting exposure of humans to ionizing radiation are based on the linear-no-threshold (LNT) hypothesis for radiation carcinogenesis under which cancer risk increases linearly as the radiation dose increases. With the LNT model even a very small dose could cause cancer and the model is used in establishing guidelines for limiting radiation exposure of humans. A slope change at low doses and dose rates is implemented using an empirical dose and dose rate effectiveness factor (DDREF). This imposes usually unacknowledged nonlinearity but not a threshold in the dose-response curve for cancer induction. In contrast, with the hormetic model, low doses of radiation reduce the cancer incidence while it is elevated after high doses. Based on a review of epidemiological and other data for exposure to low radiation doses and dose rates, it was found that the LNT model fails badly. Cancer risk after ordinarily encountered radiation exposure (medical X-rays, natural background radiation, etc.) is much lower than projections based on the LNT model and is often less than the risk for spontaneous cancer (a hormetic response). Understanding the mechanistic basis for hormetic responses will provide new insights about both risks and benefits from low-dose radiation exposure. PMID:20585444

  18. Radiation-Induced Second Cancer Risk Estimates From Radionuclide Therapy

    NASA Astrophysics Data System (ADS)

    Bednarz, Bryan; Besemer, Abigail

    2017-09-01

    The use of radionuclide therapy in the clinical setting is expected to increase significantly over the next decade. There is an important need to understand the radiation-induced second cancer risk associated with these procedures. In this study the radiation-induced cancer risk in five radionuclide therapy patients was investigated. These patients underwent serial SPECT imaging scans following injection as part of a clinical trial testing the efficacy of a 131Iodine-labeled radiopharmaceutical. Using these datasets the committed absorbed doses to multiple sensitive structures were calculated using RAPID, which is a novel Monte Carlo-based 3D dosimetry platform developed for personalized dosimetry. The excess relative risk (ERR) for radiation-induced cancer in these structures was then derived from these dose estimates following the recommendations set forth in the BEIR VII report. The radiation-induced leukemia ERR was highest among all sites considered reaching a maximum value of approximately 4.5. The radiation-induced cancer risk in the kidneys, liver and spleen ranged between 0.3 and 1.3. The lifetime attributable risks (LARs) were also calculated, which ranged from 30 to 1700 cancers per 100,000 persons and were highest for leukemia and the liver for both males and females followed by radiation-induced spleen and kidney cancer. The risks associated with radionuclide therapy are similar to the risk associated with external beam radiation therapy.

  19. Interpreting snowpack radiometry using currently existing microwave radiative transfer models

    NASA Astrophysics Data System (ADS)

    Kang, Do-Hyuk; Tang, Shurun; Kim, Edward J.

    2015-10-01

    A radiative transfer model (RTM) to calculate the snow brightness temperatures (Tb) is a critical element in terrestrial snow parameter retrieval from microwave remote sensing observations. The RTM simulates the Tb based on a layered snow by solving a set of microwave radiative transfer equations. Even with the same snow physical inputs to drive the RTM, currently existing models such as Microwave Emission Model of Layered Snowpacks (MEMLS), Dense Media Radiative Transfer (DMRT-QMS), and Helsinki University of Technology (HUT) models produce different Tb responses. To backwardly invert snow physical properties from the Tb, differences from RTMs are first to be quantitatively explained. To this end, this initial investigation evaluates the sources of perturbations in these RTMs, and reveals the equations where the variations are made among the three models. Modelling experiments are conducted by providing the same but gradual changes in snow physical inputs such as snow grain size, and snow density to the 3 RTMs. Simulations are conducted with the frequencies consistent with the Advanced Microwave Scanning Radiometer- E (AMSR-E) at 6.9, 10.7, 18.7, 23.8, 36.5, and 89.0 GHz. For realistic simulations, the 3 RTMs are simultaneously driven by the same snow physics model with the meteorological forcing datasets and are validated against the snow insitu samplings from the CLPX (Cold Land Processes Field Experiment) 2002-2003, and NoSREx (Nordic Snow Radar Experiment) 2009-2010.

  20. Interpreting snowpack radiometry using currently existing microwave radiative transfer models

    NASA Astrophysics Data System (ADS)

    Kang, D. H.; Tan, S.; Kim, E. J.

    2015-12-01

    A radiative transfer model (RTM) to calculate a snow brightness temperature (Tb) is a critical element to retrieve terrestrial snow from microwave remote sensing observations. The RTM simulates the Tb based on a layered snow by solving a set of microwave radiative transfer formulas. Even with the same snow physical inputs used for the RTM, currently existing models such as Microwave Emission Model of Layered Snowpacks (MEMLS), Dense Media Radiative Transfer (DMRT-Tsang), and Helsinki University of Technology (HUT) models produce different Tb responses. To backwardly invert snow physical properties from the Tb, the differences from the RTMs are to be quantitatively explained. To this end, the paper evaluates the sources of perturbations in the RTMs, and reveals the equations where the variations are made among three models. Investigations are conducted by providing the same but gradual changes in snow physical inputs such as snow grain size, and snow density to the 3 RTMs. Simulations are done with the frequencies consistent with the Advanced Microwave Scanning Radiometer-E (AMSR-E) at 6.9, 10.7, 18.7, 23.8, 36.5, and 89.0 GHz. For realistic simulations, the 3 RTMs are simultaneously driven by the same snow physics model with the meteorological forcing datasets and are validated from the snow core samplings from the CLPX (Cold Land Processes Field Experiment) 2002-2003, and NoSREx (Nordic Snow Radar Experiment) 2009-2010.

  1. Improvements to the Ionizing Radiation Risk Assessment Program for NASA Astronauts

    NASA Technical Reports Server (NTRS)

    Semones, E. J.; Bahadori, A. A.; Picco, C. E.; Shavers, M. R.; Flores-McLaughlin, J.

    2011-01-01

    To perform dosimetry and risk assessment, NASA collects astronaut ionizing radiation exposure data from space flight, medical imaging and therapy, aviation training activities and prior occupational exposure histories. Career risk of exposure induced death (REID) from radiation is limited to 3 percent at a 95 percent confidence level. The Radiation Health Office at Johnson Space Center (JSC) is implementing a program to integrate the gathering, storage, analysis and reporting of astronaut ionizing radiation dose and risk data and records. This work has several motivations, including more efficient analyses and greater flexibility in testing and adopting new methods for evaluating risks. The foundation for these improvements is a set of software tools called the Astronaut Radiation Exposure Analysis System (AREAS). AREAS is a series of MATLAB(Registered TradeMark)-based dose and risk analysis modules that interface with an enterprise level SQL Server database by means of a secure web service. It communicates with other JSC medical and space weather databases to maintain data integrity and consistency across systems. AREAS is part of a larger NASA Space Medicine effort, the Mission Medical Integration Strategy, with the goal of collecting accurate, high-quality and detailed astronaut health data, and then securely, timely and reliably presenting it to medical support personnel. The modular approach to the AREAS design accommodates past, current, and future sources of data from active and passive detectors, space radiation transport algorithms, computational phantoms and cancer risk models. Revisions of the cancer risk model, new radiation detection equipment and improved anthropomorphic computational phantoms can be incorporated. Notable hardware updates include the Radiation Environment Monitor (which uses Medipix technology to report real-time, on-board dosimetry measurements), an updated Tissue-Equivalent Proportional Counter, and the Southwest Research Institute

  2. Predictions of space radiation fatality risk for exploration missions

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis A.; To, Khiet; Cacao, Eliedonna

    2017-05-01

    In this paper we describe revisions to the NASA Space Cancer Risk (NSCR) model focusing on updates to probability distribution functions (PDF) representing the uncertainties in the radiation quality factor (QF) model parameters and the dose and dose-rate reduction effectiveness factor (DDREF). We integrate recent heavy ion data on liver, colorectal, intestinal, lung, and Harderian gland tumors with other data from fission neutron experiments into the model analysis. In an earlier work we introduced distinct QFs for leukemia and solid cancer risk predictions, and here we consider liver cancer risks separately because of the higher RBE's reported in mouse experiments compared to other tumors types, and distinct risk factors for liver cancer for astronauts compared to the U.S. population. The revised model is used to make predictions of fatal cancer and circulatory disease risks for 1-year deep space and International Space Station (ISS) missions, and a 940 day Mars mission. We analyzed the contribution of the various model parameter uncertainties to the overall uncertainty, which shows that the uncertainties in relative biological effectiveness (RBE) factors at high LET due to statistical uncertainties and differences across tissue types and mouse strains are the dominant uncertainty. NASA's exposure limits are approached or exceeded for each mission scenario considered. Two main conclusions are made: 1) Reducing the current estimate of about a 3-fold uncertainty to a 2-fold or lower uncertainty will require much more expansive animal carcinogenesis studies in order to reduce statistical uncertainties and understand tissue, sex and genetic variations. 2) Alternative model assumptions such as non-targeted effects, increased tumor lethality and decreased latency at high LET, and non-cancer mortality risks from circulatory diseases could significantly increase risk estimates to several times higher than the NASA limits.

  3. Predictions of space radiation fatality risk for exploration missions.

    PubMed

    Cucinotta, Francis A; To, Khiet; Cacao, Eliedonna

    2017-05-01

    In this paper we describe revisions to the NASA Space Cancer Risk (NSCR) model focusing on updates to probability distribution functions (PDF) representing the uncertainties in the radiation quality factor (QF) model parameters and the dose and dose-rate reduction effectiveness factor (DDREF). We integrate recent heavy ion data on liver, colorectal, intestinal, lung, and Harderian gland tumors with other data from fission neutron experiments into the model analysis. In an earlier work we introduced distinct QFs for leukemia and solid cancer risk predictions, and here we consider liver cancer risks separately because of the higher RBE's reported in mouse experiments compared to other tumors types, and distinct risk factors for liver cancer for astronauts compared to the U.S. The revised model is used to make predictions of fatal cancer and circulatory disease risks for 1-year deep space and International Space Station (ISS) missions, and a 940 day Mars mission. We analyzed the contribution of the various model parameter uncertainties to the overall uncertainty, which shows that the uncertainties in relative biological effectiveness (RBE) factors at high LET due to statistical uncertainties and differences across tissue types and mouse strains are the dominant uncertainty. NASA's exposure limits are approached or exceeded for each mission scenario considered. Two main conclusions are made: 1) Reducing the current estimate of about a 3-fold uncertainty to a 2-fold or lower uncertainty will require much more expansive animal carcinogenesis studies in order to reduce statistical uncertainties and understand tissue, sex and genetic variations. 2) Alternative model assumptions such as non-targeted effects, increased tumor lethality and decreased latency at high LET, and non-cancer mortality risks from circulatory diseases could significantly increase risk estimates to several times higher than the NASA limits. Copyright © 2017 The Committee on Space Research (COSPAR

  4. 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

  5. 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.

  6. 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.

  7. Limited Stage Follicular Lymphoma: Current Role of Radiation Therapy

    PubMed Central

    Filippi, Andrea Riccardo; Ciammella, Patrizia; Ricardi, Umberto

    2016-01-01

    Radiation therapy (RT) alone has been considered for a long time as the standard therapeutic option for limited stage FL, due to its high efficacy in terms of local disease control with a quite significant proportion of “cured” patients (without further relapses at 10–15 years). Multiple therapeutic choices are currently accepted for the management of early stage FL at diagnosis, and better staging procedures as well as better systemic therapy partially modified the role of RT in this setting. RT has also changed in terms of prescribed dose as well as treatment volumes. In this review, we present and discuss the current role of RT for limited stage FL in light of the historical data and the modern RT concepts along with the possible combination with systemic therapy. PMID:27648204

  8. Short-Term Forecasting of Radiation Belt and Ring Current

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching

    2007-01-01

    A computer program implements a mathematical model of the radiation-belt and ring-current plasmas resulting from interactions between the solar wind and the Earth s magnetic field, for the purpose of predicting fluxes of energetic electrons (10 keV to 5 MeV) and protons (10 keV to 1 MeV), which are hazardous to humans and spacecraft. Given solar-wind and interplanetary-magnetic-field data as inputs, the program solves the convection-diffusion equations of plasma distribution functions in the range of 2 to 10 Earth radii. Phenomena represented in the model include particle drifts resulting from the gradient and curvature of the magnetic field; electric fields associated with the rotation of the Earth, convection, and temporal variation of the magnetic field; and losses along particle-drift paths. The model can readily accommodate new magnetic- and electric-field submodels and new information regarding physical processes that drive the radiation-belt and ring-current plasmas. Despite the complexity of the model, the program can be run in real time on ordinary computers. At present, the program can calculate present electron and proton fluxes; after further development, it should be able to predict the fluxes 24 hours in advance

  9. Radiation damage of biomolecules (RADAM) database development: current status

    NASA Astrophysics Data System (ADS)

    Denifl, S.; Garcia, G.; Huber, B. A.; Marinković, B. P.; Mason, N.; Postler, J.; Rabus, H.; Rixon, G.; Solov'yov, A. V.; Suraud, E.; Yakubovich, A. V.

    2013-06-01

    Ion beam therapy offers the possibility of excellent dose localization for treatment of malignant tumours, minimizing radiation damage in normal tissue, while maximizing cell killing within the tumour. However, as the underlying dependent physical, chemical and biological processes are too complex to treat them on a purely analytical level, most of our current and future understanding will rely on computer simulations, based on mathematical equations, algorithms and last, but not least, on the available atomic and molecular data. The viability of the simulated output and the success of any computer simulation will be determined by these data, which are treated as the input variables in each computer simulation performed. The radiation research community lacks a complete database for the cross sections of all the different processes involved in ion beam induced damage: ionization and excitation cross sections for ions with liquid water and biological molecules, all the possible electron - medium interactions, dielectric response data, electron attachment to biomolecules etc. In this paper we discuss current progress in the creation of such a database, outline the roadmap of the project and review plans for the exploitation of such a database in future simulations.

  10. Current Evidence for Developmental, Structural, and Functional Brain Defects following Prenatal Radiation Exposure

    PubMed Central

    Verreet, Tine; Quintens, Roel; Baatout, Sarah; Benotmane, Mohammed A.

    2016-01-01

    Ionizing radiation is omnipresent. We are continuously exposed to natural (e.g., radon and cosmic) and man-made radiation sources, including those from industry but especially from the medical sector. The increasing use of medical radiation modalities, in particular those employing low-dose radiation such as CT scans, raises concerns regarding the effects of cumulative exposure doses and the inappropriate utilization of these imaging techniques. One of the major goals in the radioprotection field is to better understand the potential health risk posed to the unborn child after radiation exposure to the pregnant mother, of which the first convincing evidence came from epidemiological studies on in utero exposed atomic bomb survivors. In the following years, animal models have proven to be an essential tool to further characterize brain developmental defects and consequent functional deficits. However, the identification of a possible dose threshold is far from complete and a sound link between early defects and persistent anomalies has not yet been established. This review provides an overview of the current knowledge on brain developmental and persistent defects resulting from in utero radiation exposure and addresses the many questions that still remain to be answered. PMID:27382490

  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. 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.

  13. 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.

  14. Stormtime transport of ring current and radiation belt ions

    NASA Technical Reports Server (NTRS)

    Chen, Margaret W.; Schulz, Michael; Lyons, Larry R.; Gorney, David J.

    1993-01-01

    A dynamical guiding-center simulation model is used to study the stormtime ion transport which leads to the formation of the ring current and diffusion in the radiation belts. Representative ions guiding-center motion in response to model storm-associated impulses in the convection electric field is traced for a range of ion mu values. The present numerical results are compared with previously formulated limiting idealization of particle transport in order to assess the limits of validity of these approximations. For ions having drift periods that exceed the duration of the main phase of the storm, their inward transport to form the stormtime ring current is appropriately described as direct convective access. For ions having drift periods comparable to the duration of the main phase of the storm, there is a transition between direct convective access and transport that resembles radial diffusion. Lower-energy ring-current ions at L of about 3 are freshly injected there from open adiabatic trajectories, whereas the higher-energy ring-current population consists of a mixture of freshly injected and previously trapped ions.

  15. 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)

  16. 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.

  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. Copyright © 2015 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

  19. 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.

  20. 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.

  1. Antidiabetic drugs and stroke risk. Current evidence.

    PubMed

    Castilla-Guerra, Luis; Fernandez-Moreno, María Del Carmen; Leon-Jimenez, David; Carmona-Nimo, Eduardo

    2017-09-20

    Cardiovascular disease (CVD) is the major cause of morbidity and mortality for individuals with type 2 diabetes (T2D). In particular, the risk for stroke is twice that of patients without diabetes, and diabetes may be responsible for >8% of first ischemic strokes. Therefore, the way to prevent stroke in these patients has become an important issue. Traditionally, glucose-lowering drugs had not been shown to protect against stroke. Moreover, several antidiabetic drugs (i.e., sulfonylureas, rosiglitazone) have been reported to be associated with increased risks of CVD and stroke. On the contrary, data on the CV risks and benefits associated with new antidiabetic treatment in patients with T2D are emerging - and look promising. Therefore, it could be of great value to find out if any type of these new antidiabetic agents has protective effect against stroke. We review the available evidence regarding the risk of stroke in individuals taking non-insulin antidiabetic agents. To date, several antidiabetic agents have shown to have a positive effect on stroke prevention. The accumulated evidence suggests that metformin, pioglitazone and semaglutide reduce stroke risk. These agents do not represent only a way of controlling blood glucose and but also offer the opportunity to reduce stroke risk. Surely, new data from ongoing and future studies will provide additional information to select the best treatment for decreasing stroke risk in T2D patients. Copyright © 2017. Published by Elsevier B.V.

  2. Current Trends in Gamma Radiation Detection for Radiological Emergency Response

    SciTech Connect

    Mukhopadhyay, S., Guss, P., Maurer, R.

    2011-09-01

    Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of interdisciplinary research and development has taken place–techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation–the so-called second line of defense.

  3. Current trends in gamma radiation detection for radiological emergency response

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Guss, Paul; Maurer, Richard

    2011-09-01

    Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of inter-disciplinary research and development has taken place-techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation-the so-called second line of defense.

  4. Risks of exposure to ionizing and millimeter-wave radiation from airport whole-body scanners.

    PubMed

    Moulder, John E

    2012-06-01

    Considerable public concern has been expressed around the world about the radiation risks posed by the backscatter (ionizing radiation) and millimeter-wave (nonionizing radiation) whole-body scanners that have been deployed at many airports. The backscatter and millimeter-wave scanners currently deployed in the U.S. almost certainly pose negligible radiation risks if used as intended, but their safety is difficult-to-impossible to prove using publicly accessible data. The scanners are widely disliked and often feared, which is a problem made worse by what appears to be a veil of secrecy that covers their specifications and dosimetry. Therefore, for these and future similar technologies to gain wide acceptance, more openness is needed, as is independent review and regulation. Publicly accessible, and preferably peer-reviewed evidence is needed that the deployed units (not just the prototypes) meet widely-accepted safety standards. It is also critical that risk-perception issues be handled more competently.

  5. Current Challenges in Neurotoxicity Risk Assessment ...

    EPA Pesticide Factsheets

    Neurotoxicity risk assessment must continue to evolve in parallel with advances in basic research. Along with this evolution is an expansion in the scope of neurotoxicity assessments of environmental health risks. Examples of this expansion include an increasing emphasis on complex animal models that better replicate human behavior and a wider array of molecular and mechanistic data relevant to interpreting the underlying cause(s) of toxicity. However, modern neurotoxicology studies are often more nuanced and complicated than traditional studies, and they often vary considerably in evaluation methods from one study to the next, impeding comparisons. This can pose particular difficulties for risk assessors, especially given the recent demand for chemical risk assessments to be more systematic and transparent. This presentation will introduce and provide some examples of specific challenges in neurotoxicity assessments of environmental chemicals. Some of these challenges are relatively new to the field, such as the incorporation of data on neuron-supportive glial cells into hazard characterization, while other challenges have persisted for several decades, but only recently are studies being designed to evaluate them, including analyses of latent neurotoxicity. The examples provided illustrate some future research areas of interest for scientists and risk assessors examining human neurotoxicity risk. This abstract will be presented to internal U.S. Food and Drug A

  6. Current Challenges in Neurotoxicity Risk Assessment ...

    EPA Pesticide Factsheets

    Neurotoxicity risk assessment must continue to evolve in parallel with advances in basic research. Along with this evolution is an expansion in the scope of neurotoxicity assessments of environmental health risks. Examples of this expansion include an increasing emphasis on complex animal models that better replicate human behavior and a wider array of molecular and mechanistic data relevant to interpreting the underlying cause(s) of toxicity. However, modern neurotoxicology studies are often more nuanced and complicated than traditional studies, and they often vary considerably in evaluation methods from one study to the next, impeding comparisons. This can pose particular difficulties for risk assessors, especially given the recent demand for chemical risk assessments to be more systematic and transparent. This presentation will introduce and provide some examples of specific challenges in neurotoxicity assessments of environmental chemicals. Some of these challenges are relatively new to the field, such as the incorporation of data on neuron-supportive glial cells into hazard characterization, while other challenges have persisted for several decades, but only recently are studies being designed to evaluate them, including analyses of latent neurotoxicity. The examples provided illustrate some future research areas of interest for scientists and risk assessors examining human neurotoxicity risk. This abstract will be presented to internal U.S. Food and Drug A

  7. 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.

  8. 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).

  9. Assessment of knowledge and awareness among radiology personnel regarding current computed tomography technology and radiation dose

    NASA Astrophysics Data System (ADS)

    Karim, M. K. A.; Hashim, S.; Bradley, D. A.; Bahruddin, N. A.; Ang, W. C.; Salehhon, N.

    2016-03-01

    In this paper, we evaluate the level of knowledge and awareness among 120 radiology personnel working in 7 public hospitals in Johor, Malaysia, concerning Computed Tomography (CT) technology and radiation doses based on a set of questionnaires. Subjects were divided into two groups (Medical profession (Med, n=32) and Allied health profession (AH, n=88). The questionnaires are addressed: (1) demographic data (2) relative radiation dose and (3) knowledge of current CT technology. One-third of respondents from both groups were able to estimate relative radiation dose for routine CT examinations. 68% of the allied health profession personnel knew of the Malaysia regulations entitled ‘Basic Safety Standard (BSS) 2010’, although notably 80% of them had previously attended a radiation protection course. No significant difference (p < 0.05) in mean scores of CT technology knowledge detected between the two groups, with the medical professions producing a mean score of (26.7 ± 2.7) and the allied health professions a mean score of (25.2 ± 4.3). This study points to considerable variation among the respondents concerning their understanding of knowledge and awareness of risks of radiation and CT optimization techniques.

  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. 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.

  13. 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

  14. 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

  15. Gravitational radiation theory. M.A. Thesis - Rice Univ.; [survey of current research

    NASA Technical Reports Server (NTRS)

    Wilson, T. L.

    1973-01-01

    A survey is presented of current research in the theory of gravitational radiation. The mathematical structure of gravitational radiation is stressed. Furthermore, the radiation problem is treated independently from other problems in gravitation. The development proceeds candidly through three points of view - scalar, rector, and tensor radiation theory - and the corresponding results are stated.

  16. ["Dose-risk" relationships at low doses of radiation].

    PubMed

    Stefanou, E P

    1988-01-01

    The ionizing radiation is inherently harmful to human beings, and people must be protected from unnecessary or excessive exposure to it. The harmful nature of high doses of x rays has been known for many years. However, for low doses such as those commonly employed in dental radiographic procedures the magnitude of the risk (or even if there is a risk) remains uncertain. The purpose of this paper is to do an analysis of the Dose-risk relationships at low doses of radiation according to the latest recommendations and philosophy of the International Commission on Radiological Protection (ICRP).

  17. 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

  18. [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.

  19. 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.

  20. 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.

  1. 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.

  2. Intensity modulated radiation therapy for breast cancer: current perspectives

    PubMed Central

    Buwenge, Milly; Cammelli, Silvia; Ammendolia, Ilario; Tolento, Giorgio; Zamagni, Alice; Arcelli, Alessandra; Macchia, Gabriella; Deodato, Francesco; Cilla, Savino; Morganti, Alessio G

    2017-01-01

    Background Owing to highly conformed dose distribution, intensity modulated radiation therapy (IMRT) has the potential to improve treatment results of radiotherapy (RT). Postoperative RT is a standard adjuvant treatment in conservative treatment of breast cancer (BC). The aim of this review is to analyze available evidence from randomized controlled trials (RCTs) on IMRT in BC, particularly in terms of reduction of side effects. Methods A literature search of the bibliographic database PubMed, from January 1990 through November 2016, was performed. Only RCTs published in English were included. Results Ten articles reporting data from 5 RCTs fulfilled the selection criteria and were included in our review. Three out of 5 studies enrolled only selected patients in terms of increased risk of toxicity. Three studies compared IMRT with standard tangential RT. One study compared the results of IMRT in the supine versus the prone position, and one study compared standard treatment with accelerated partial breast IMRT. Three studies reported reduced acute and/or late toxicity using IMRT compared with standard RT. No study reported improved quality of life. Conclusion IMRT seems able to reduce toxicity in selected patients treated with postoperative RT for BC. Further analyses are needed to better define patients who are candidates for this treatment modality. PMID:28293119

  3. Survey of current situation in radiation belt modeling.

    PubMed

    Fung, Shing F

    2004-01-01

    The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling.

  4. 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.

  5. The challenge of risk characterization: current practice and future directions.

    PubMed Central

    Gray, G M; Cohen, J T; Graham, J D

    1993-01-01

    Risk characterization is perhaps the most important part of risk assessment. As currently practiced, risk characterizations do not convey the degree of uncertainty in a risk estimate to risk managers, Congress, the press, and the public. Here, we use a framework put forth by an ad hoc study group of industry and government scientists and academics to critique the risk characterizations contained in two risks assessments of gasoline vapor. After discussing the strengths and weaknesses of each assessment's risk characterization, we detail an alternative approach that conveys estimates in the form of a probability distribution. The distributional approach can make use of all relevant scientific data and knowledge, including alternative data sets and all plausible mechanistic theories of carcinogenesis. As a result, this approach facilitates better public health decisions than current risk characterization procedures. We discuss methodological issues, as well as strengths and weaknesses of the distributional approach. PMID:8020444

  6. [Ionizing and non-ionizing radiation (comparative risk estimations)].

    PubMed

    Grigor'ev, Iu G

    2012-01-01

    The population has widely used mobile communication for already more than 15 years. It is important to note that the use of mobile communication has sharply changed the conditions of daily exposure of the population to EME We expose our brain daily for the first time in the entire civilization. The mobile phone is an open and uncontrollable source of electromagnetic radiation. The comparative risk estimation for the population of ionizing and non-ionizing radiation was carried out taking into account the real conditions of influence. Comparison of risks for the population of ionizing and non-ionizing radiation leads us to a conclusion that EMF RF exposure in conditions of wide use of mobile communication is potentially more harmful than ionizing radiation influence.

  7. Stormtime transport of ring current and radiation belt ions

    NASA Technical Reports Server (NTRS)

    Chen, Margaret W.; Schulz, Michael; Lyons, L. R.; Gorney, David J.

    1993-01-01

    This is an investigation of stormtime particle transport that leads to formation of the ring current. Our method is to trace the guiding-center motion of representative ions (having selected first adiabatic invariants mu) in response to model substorm-associated impulses in the convection electric field. We compare our simulation results qualitatively with existing analytically tractable idealizations of particle transport (direct convective access and radial diffusion) in order to assess the limits of validity of these approximations. For mu approximately less than 10 MeV/G (E approximately less than 10 keV at L equivalent to 3) the ion drift period on the final (ring-current) drift shell of interest (L equivalent to 3) exceeds the duration of the main phase of our model storm, and we find that the transport of ions to this drift shell is appropriately idealized as direct convective access, typically from open drift paths. Ion transport to a final closed drift path from an open (plasma-sheet) drift trajectory is possible for those portions of that drift path that lie outside the mean stormtime separatrix between closed and open drift trajectories, For mu approximately 10-25 MeV/G (110 keV approximately less than E approximately less than 280 keV at L equivalent to 3) the drift period at L equivalent to 3 is comparable to the postulated 3-hr duration of the storm, and the mode of transport is transitional between direct convective access and transport that resembles radial diffusion. (This particle population is transitional between the ring current and radiation belt). For mu approximately greater than 25 MeV/G (radiation-belt ions having E approximately greater than 280 keV at L equivalent to 3) the ion drift period is considerably shorter than the main phase of a typical storm, and ions gain access to the ring-current region essentially via radial diffusion. By computing the mean and mean-square cumulative changes in 1/L among (in this case) 12 representative

  8. 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.

  9. 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.

  10. Current Perspectives on Occupational Cancer Risks.

    PubMed

    Boffetta; Kogevinas; Simonato; Wilbourn; Saracci

    1995-10-01

    On the basis of the International Agency for Research on Cancer's evaluations of occupational exposures, 22 occupational agents are classified as human carcinogens and an additional 22 agents as probable human carcinogens. In addition, evidence of increased risk of cancer was associated with particular industries and occupations, although no specific agents could be identified as etiologic factors. The main problem in the construction and interpretation of such lists is the lack of detailed qualitative and quantitative knowledge about exposures to known or suspected carcinogens. The recent examples of recognized occupational carcinogens, such as cadmium, beryllium, and ethylene oxide, stress the importance of the refinement in the methods for exposure assessment and for statistical analysis on the one hand and the potential benefits from the application of biomarkers of exposure and early effect on the other hand. Other trends that may be identified include the increasing practice of multicentric studies and investigations of exposures relevant to white collar workers and women. Finally, there is a need for investigation of occupational cancer risks in developing countries.

  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. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. The Earth-Moon-Mars Radiation Environment Module (EMMREM): Framework and Current Developments

    NASA Astrophysics Data System (ADS)

    Kozarev, K. A.; Schwadron, N. A.; Townsend, L. W.; Hatcher, R.; Desai, M.; Al-Dayeh, M.; Squier, R.

    2009-04-01

    As the international space community is preparing to return humans to the Moon, and to set the stage for manned exploration of Mars, it remains unclear if long missions outside of Low-Earth Orbit (LEO) can be accomplished with acceptable risk. The central objective of our project, the Earth-Moon-Mars Radiation Environment Module (EMMREM), is to create a reliable numerical model for completely characterizing time-dependent radiation exposure in the Earth-Moon-Mars and Interplanetary space environments. EMMREM includes several submodules-an energetic particle transport code (EPREM), a baryon transport code (BRYNTRN), submodules for input and output, and visualization. EPREM (Energetic Particles Radiation Environment Module) is a 3D parallelized kinetic code, the core of EMMREM. It is being integrated into the EMMREM framework, and we've introduced accurate positions for solar system bodies, spacecraft, and other observers within the code, using the NASA SPICE package. The EMMREM framework is currently being comprehensively validated using well-studied solar energetic proton events. The results of EMMREM will improve risk assessment models so that future human exploration missions can be adequately planned.

  20. 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.

  1. Cancer and Radiation Therapy: Current Advances and Future Directions

    PubMed Central

    Baskar, Rajamanickam; Lee, Kuo Ann; Yeo, Richard; Yeoh, Kheng-Wei

    2012-01-01

    In recent years remarkable progress has been made towards the understanding of proposed hallmarks of cancer development and treatment. However with its increasing incidence, the clinical management of cancer continues to be a challenge for the 21st century. Treatment modalities comprise of radiation therapy, surgery, chemotherapy, immunotherapy and hormonal therapy. Radiation therapy remains an important component of cancer treatment with approximately 50% of all cancer patients receiving radiation therapy during their course of illness; it contributes towards 40% of curative treatment for cancer. The main goal of radiation therapy is to deprive cancer cells of their multiplication (cell division) potential. Celebrating a century of advances since Marie Curie won her second Nobel Prize for her research into radium, 2011 has been designated the Year of Radiation therapy in the UK. Over the last 100 years, ongoing advances in the techniques of radiation treatment and progress made in understanding the biology of cancer cell responses to radiation will endeavor to increase the survival and reduce treatment side effects for cancer patients. In this review, principles, application and advances in radiation therapy with their biological end points are discussed. PMID:22408567

  2. Current status and perspectives of synchrotron radiation in medicine

    SciTech Connect

    Thomlinson, W.

    1996-11-01

    The high flux and brightness, tunable beams, time structure and polarization of synchrotron radiation provide an ideal x-ray source for many medical applications. The present status of synchrotron angiography, multiple energy computed tomography, mammography and radiation therapy at laboratories around the world is reviewed and some future projections for these applications are addressed.

  3. [Hygienic assessment of the radiation risk of radon emanation in the Altai Krai].

    PubMed

    Saldan, I P; Balandovich, B A; Potseluev, N Yu; Flat, M Kh

    2014-01-01

    The unique climatic and geographical location of the Altai Krai determines the specific radiation dose load for the population, which is composed of the complex of radiological indices, the structure of which is largely dependent on the type of locality and, to a greater extent due to the action of radon, which is currently the main source of internal radiation of the population of upland districts and adjacent territories. There was performed a hygienic assessment of the radiation risk and the expected decline in life expectancy and population health due to radon exposure in the model areas of the Altai Krai. To calculate the additional risk there were used some models for radiation risk extrapolation: a risk constant model, model GSF (Jacobi's model), Lubin model (TSE/AGE/WL) and BEIR VI model for smoking and nonsmoking population, as well as the combined model. The lowest values of the radiation risk and the expected decline in life expectancy are typical for Charyshsko-Ust-Kalmanskaya zone, the maximum--for Kuryinsko--Pospelikhinskaya zone.

  4. 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.

  5. Risk Assessment of Radiation Exposure using Molecular Biodosimetry

    NASA Technical Reports Server (NTRS)

    Elliott, Todd F.; George, K.; Hammond, D. K.; Cucinotta, F. A.

    2007-01-01

    Current cytogenetic biodosimetry methods would be difficult to adapt to spaceflight operations, because they require toxic chemicals and a substantial amount of time to perform. In addition, current biodosimetry techniques are limited to whole body doses over about 10cGy. Development of new techniques that assess radiation exposure response at the molecular level could overcome these limitations and have important implications in the advancement of biodosimetry. Recent technical advances include expression profiling at the transcript and protein level to assess multiple biomarkers of exposure, which may lead to the development of a radiation biomarker panel revealing possible fingerprints of individual radiation sensitivity. So far, many biomarkers of interest have been examined in their response to ionizing radiation, such as cytokines and members of the DNA repair pathway. New technology, such as the Luminex system can analyze many biomarkers simultaneously in one sample.

  6. Risk Assessment of Radiation Exposure using Molecular Biodosimetry

    NASA Technical Reports Server (NTRS)

    Elliott, Todd F.; George, K.; Hammond, D. K.; Cucinotta, F. A.

    2007-01-01

    Current cytogenetic biodosimetry methods would be difficult to adapt to spaceflight operations, because they require toxic chemicals and a substantial amount of time to perform. In addition, current biodosimetry techniques are limited to whole body doses over about 10cGy. Development of new techniques that assess radiation exposure response at the molecular level could overcome these limitations and have important implications in the advancement of biodosimetry. Recent technical advances include expression profiling at the transcript and protein level to assess multiple biomarkers of exposure, which may lead to the development of a radiation biomarker panel revealing possible fingerprints of individual radiation sensitivity. So far, many biomarkers of interest have been examined in their response to ionizing radiation, such as cytokines and members of the DNA repair pathway. New technology, such as the Luminex system can analyze many biomarkers simultaneously in one sample.

  7. 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

  8. Moscow State University near-Earth radiation monitoring satellite system: current status and development

    NASA Astrophysics Data System (ADS)

    Panasyuk, Mikhail

    2016-07-01

    Radiation measurements using instruments have been designed and manufacturing in the Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University and installed onboard different satellites,i.e. LEO -"Meteor", ISS, GPS - GLONASS, GEO - "Electro" are presented as a basis of radiation monitoring system for control of radiation condition with a goal for to decrease radiation risk of spacecraft's damage on different orbits. Development of this system including radiation measurements onboard "Lomonosov"(LEO) satellite will be presented as well together with future project of multispacecraft LEO system for radiation monitoring.

  9. 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.

  10. 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

  11. 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

  12. Survey of current situation in radiation belt modeling

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.

    2004-01-01

    The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.

  13. Survey of current situation in radiation belt modeling

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.

    2004-01-01

    The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.

  14. [Evaluation of the radiation risk of determinate effects from space radiation in a piloted mission to Mars].

    PubMed

    Petrov, V M; Vlasov, A G

    2004-01-01

    Solar cosmic rays (SCR) are one of the sources of radiation risk specific to space flights. On Earth, occupational exposure has a regular character and radiation risk is an attribute of nothing else but stochasticity of radiobiological effects. In space flight, SCR impart stochasticity to the radiation environment and, therefore, probability to all, including determinate, radiobiological effects. The most dangerous effect is radiation disease the dosimetric functional of which is an equivalent dose to the blood-forming organs. In addition, this radiation pathology is modulated by reparative processes in the blood-forming tissue which must be also taken into account during radiation risk evaluation. Using the speculated mission to Mars as an example, it was shown that radiation risk of determinate effects defined as probability of death by radiation disease in consequence of exposure to SCR can be comparable in value to the risk from stochastic effects.

  15. [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.

  16. 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

  17. Radiation Power Affected by Current and Wall Radius in Water Cooled Vortex Wall-stabilized Arc

    NASA Astrophysics Data System (ADS)

    Iwao, Toru; Nakamura, Takaya; Yanagi, Kentaro; Yamamoto, Shinji

    2015-11-01

    The arc lighting to obtain the environment to evacuate, save the life, keep the safety and be comfortable are focus on. The lack of radiation intensity and color rendering is problem because of inappropriate energy balance. Some researchers have researched the arc lamp mixed with metal vapor for improvement of color rendering spectrum. The metal vapor can emit the high intense radiation. In addition, the radiation is derived from the high temperature medium. Because the arc temperature can be controlled by current and arc radius, the radiation can be controlled by the current and arc radius. This research elucidates the radiation power affected by the current and wall radius in wall-stabilized arc of water-cooled vortex type. As a result, the radiation power increases with increasing the square of current / square of wall radius because of the temperature distribution which is derived from the current density at the simulation.

  18. RadRAT: a radiation risk assessment tool for lifetime cancer risk projection.

    PubMed

    Berrington de Gonzalez, Amy; Iulian Apostoaei, A; Veiga, Lene H S; Rajaraman, Preetha; Thomas, Brian A; Owen Hoffman, F; Gilbert, Ethel; Land, Charles

    2012-09-01

    Risk projection methods allow for timely assessment of the potential magnitude of radiation-related cancer risks following low-dose radiation exposures. The estimation of such risks directly through observational studies would generally require infeasibly large studies and long-term follow-up to achieve reasonable statistical power. We developed an online radiation risk assessment tool (RadRAT) which can be used to estimate the lifetime risk of radiation-related cancer with uncertainty intervals following a user-specified exposure history (https://irep.nci.nih.gov/radrat). The uncertainty intervals constitute a key component of the program because of the various assumptions that are involved in such calculations. The risk models used in RadRAT are broadly based on those developed by the BEIR VII committee for estimating lifetime risk following low-dose radiation exposure of the US population for eleven site-specific cancers. We developed new risk models for seven additional cancer sites, oral, oesophagus, gallbladder, pancreas, rectum, kidney and brain/central nervous system (CNS) cancers, using data from Japanese atomic bomb survivors. The lifetime risk estimates are slightly higher for RadRAT than for BEIR VII across all exposure ages mostly because the weighting of the excess relative risk and excess absolute risk models was conducted on an arithmetic rather than a logarithmic scale. The calculator can be used to estimate lifetime cancer risk from both uniform and non-uniform doses that are acute or chronic. It is most appropriate for low-LET radiation doses < 1 Gy, and for individuals with life-expectancy and cancer rates similar to the general population in the US.

  19. Current and Future Challenges in Radiation Effects on CMOS Electronics

    NASA Astrophysics Data System (ADS)

    Dodd, P. E.; Shaneyfelt, M. R.; Schwank, J. R.; Felix, J. A.

    2010-08-01

    Advances in microelectronics performance and density continue to be fueled by the engine of Moore's law. Although lately this engine appears to be running out of steam, recent developments in advanced technologies have brought about a number of challenges and opportunities for their use in radiation environments. For example, while many advanced CMOS technologies have generally shown improving total dose tolerance, single-event effects continue to be a serious concern for highly scaled technologies. In this paper, we examine the impact of recent developments and the challenges they present to the radiation effects community. Topics covered include the impact of technology scaling on radiation response and technology challenges for both total dose and single-event effects. We include challenges for hardening and mitigation techniques at the nanometer scale. Recent developments leading to hardness assurance challenges are covered. Finally, we discuss future radiation effects challenges as the electronics industry looks beyond Moore's law to alternatives to traditional CMOS technologies.

  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. Dose-Volume Analysis of Radiation Nephropathy in Children: Preliminary Report of the Risk Consortium

    SciTech Connect

    Boelling, Tobias; Ernst, Iris; Pape, Hildegard; Martini, Carmen; Ruebe, Christian; Fischedick, Karin; Kortmann, Rolf-Dieter; Willich, Normann

    2011-07-01

    Purpose: To characterize kidney function in children and adolescents who had undergone radiation treatment that included parts of the kidney. Methods and Materials: Patients receiving radiotherapy during childhood or adolescence were prospectively registered in Germany's Registry for the Evaluation of Side Effects after Radiation in Childhood and Adolescence (RiSK). Detailed information was recorded regarding radiation doses at the organs at risk since 2001 all over Germany. Toxicity evaluation was performed according to standardized Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria. Results: Up to May 2009, 1086 patients from 62 centers were recruited, including 126 patients (median age, 10.2 years) who underwent radiotherapy to parts of the kidneys. Maximal late toxicity (median follow-up 28.5 months in 74 patients) was characterized as Grade 0 (n = 65), 1 (n = 7) or 2 (n = 2). All patients with late effects had received potentially nephrotoxic chemotherapy. A statistically significant difference between patients with and without Grade 1 toxicity, revealing higher exposed kidney volumes in patients with toxicity, was seen for the kidney volume exposed to 20 Gy (V20; p = 0.031) and 30 Gy (V30; p = 0.003). Conclusions: Preliminary data indicate that radiation-induced kidney function impairment is rare in current pediatric multimodal treatment approaches. In the future, RiSK will be able to provide further detailed data regarding dose-volume effect relationships of radiation-associated side effects in pediatric oncology patients.

  2. Mobile phone radiation health risk controversy: the reliability and sufficiency of science behind the safety standards

    PubMed Central

    2010-01-01

    There is ongoing discussion whether the mobile phone radiation causes any health effects. The International Commission on Non-Ionizing Radiation Protection, the International Committee on Electromagnetic Safety and the World Health Organization are assuring that there is no proven health risk and that the present safety limits protect all mobile phone users. However, based on the available scientific evidence, the situation is not as clear. The majority of the evidence comes from in vitro laboratory studies and is of very limited use for determining health risk. Animal toxicology studies are inadequate because it is not possible to "overdose" microwave radiation, as it is done with chemical agents, due to simultaneous induction of heating side-effects. There is a lack of human volunteer studies that would, in unbiased way, demonstrate whether human body responds at all to mobile phone radiation. Finally, the epidemiological evidence is insufficient due to, among others, selection and misclassification bias and the low sensitivity of this approach in detection of health risk within the population. This indicates that the presently available scientific evidence is insufficient to prove reliability of the current safety standards. Therefore, we recommend to use precaution when dealing with mobile phones and, whenever possible and feasible, to limit body exposure to this radiation. Continuation of the research on mobile phone radiation effects is needed in order to improve the basis and the reliability of the safety standards. PMID:20205835

  3. 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.

  4. Risk definition and management strategies in retinoblastoma: current perspectives

    PubMed Central

    Ghassemi, Fariba; Khodabande, Alireza

    2015-01-01

    This manuscript focuses on high-risk factors of metastatic disease in retinoblastoma and evaluation of the current treatments of retinoblastoma. Presence of histopathologic high-risk factors is associated with a higher risk of local recurrence and systemic metastasis. Currently, globe-sparing therapies, including systemic chemotherapy, intra-arterial chemoreduction, intravitreal chemotherapy, focal consolidation, and combination therapies, are being used and investigated actively. Major advances are being made in the diagnosis and management of retinoblastoma that will lead to improved morbidity and mortality rates in patients with retinoblastoma. By saving the globes, fronting with some high-risk factors for metastasis would be inevitable. International multi-institutional prospective studies could resolve current uncertainties regarding the main tumor treatment regimens for each patient and indications for chemoprophylaxis for high-risk-factor-bearing retinoblastoma cases. PMID:26089630

  5. Classification of radiation effects for dose limitation purposes: history, current situation and future prospects.

    PubMed

    Hamada, Nobuyuki; Fujimichi, Yuki

    2014-07-01

    Radiation exposure causes cancer and non-cancer health effects, each of which differs greatly in the shape of the dose-response curve, latency, persistency, recurrence, curability, fatality and impact on quality of life. In recent decades, for dose limitation purposes, the International Commission on Radiological Protection has divided such diverse effects into tissue reactions (formerly termed non-stochastic and deterministic effects) and stochastic effects. On the one hand, effective dose limits aim to reduce the risks of stochastic effects (cancer/heritable effects) and are based on the detriment-adjusted nominal risk coefficients, assuming a linear-non-threshold dose response and a dose and dose rate effectiveness factor of 2. On the other hand, equivalent dose limits aim to avoid tissue reactions (vision-impairing cataracts and cosmetically unacceptable non-cancer skin changes) and are based on a threshold dose. However, the boundary between these two categories is becoming vague. Thus, we review the changes in radiation effect classification, dose limitation concepts, and the definition of detriment and threshold. Then, the current situation is overviewed focusing on (i) stochastic effects with a threshold, (ii) tissue reactions without a threshold, (iii) target organs/tissues for circulatory disease, (iv) dose levels for limitation of cancer risks vs prevention of non-life-threatening tissue reactions vs prevention of life-threatening tissue reactions, (v) mortality or incidence of thyroid cancer, and (vi) the detriment for tissue reactions. For future discussion, one approach is suggested that classifies radiation effects according to whether effects are life threatening, and radiobiological research needs are also briefly discussed.

  6. Classification of radiation effects for dose limitation purposes: history, current situation and future prospects

    PubMed Central

    Hamada, Nobuyuki; Fujimichi, Yuki

    2014-01-01

    Radiation exposure causes cancer and non-cancer health effects, each of which differs greatly in the shape of the dose–response curve, latency, persistency, recurrence, curability, fatality and impact on quality of life. In recent decades, for dose limitation purposes, the International Commission on Radiological Protection has divided such diverse effects into tissue reactions (formerly termed non-stochastic and deterministic effects) and stochastic effects. On the one hand, effective dose limits aim to reduce the risks of stochastic effects (cancer/heritable effects) and are based on the detriment-adjusted nominal risk coefficients, assuming a linear-non-threshold dose response and a dose and dose rate effectiveness factor of 2. On the other hand, equivalent dose limits aim to avoid tissue reactions (vision-impairing cataracts and cosmetically unacceptable non-cancer skin changes) and are based on a threshold dose. However, the boundary between these two categories is becoming vague. Thus, we review the changes in radiation effect classification, dose limitation concepts, and the definition of detriment and threshold. Then, the current situation is overviewed focusing on (i) stochastic effects with a threshold, (ii) tissue reactions without a threshold, (iii) target organs/tissues for circulatory disease, (iv) dose levels for limitation of cancer risks vs prevention of non-life-threatening tissue reactions vs prevention of life-threatening tissue reactions, (v) mortality or incidence of thyroid cancer, and (vi) the detriment for tissue reactions. For future discussion, one approach is suggested that classifies radiation effects according to whether effects are life threatening, and radiobiological research needs are also briefly discussed. PMID:24794798

  7. 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

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

    PubMed

    Daniels, R D; Schubauer-Berigan, M K

    2011-06-01

    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. We conducted a meta-analysis examining the relationship between protracted low-dose ionising radiation exposure and leukaemia. 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. 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. 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. 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). 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 protracted radiation exposures.

  9. Heel spur radiotherapy and radiation carcinogenesis risk estimation.

    PubMed

    Surenkok, Serdar; Dirican, Bahar; Beyzadeoglu, Murat; Oysul, Kaan

    2006-10-01

    Radiotherapy is a nonsurgical alternative therapy of painful heel spur patients. Nonetheless, cancer induction is the most important somatic effect of ionizing radiation. This study was designed to evaluate the carcinogenesis risk factor in benign painful heel spur patients treated by radiotherapy. Between 1974 and 1999, a total of 20 patients received mean 8.16 Gy total irradiation dose in two fractions. Thermoluminescent dosimeters (TLD(100)) were placed on multiple phantom sites in vivo within the irradiated volume to verify irradiation accuracy and carcinogenesis risk factor calculation. The 20 still-alive patients, who had a minimum 5-year and maximum 29-year follow-up (mean 11.9 years), have been evaluated by carcinogenic radiation risk factor on the basis of tissue weighting factors as defined by the International Commission on Radiological Protection Publication 60. Reasonable pain relief has been obtained in all 20 patients. The calculated mean carcinogenesis risk factor is 1.3% for radiation portals in the whole group, and no secondary cancer has been clinically observed. Radiotherapy is an effective treatment modality for relieving pain in calcaneal spur patients. The estimated secondary cancer risk factor for irradiation of this benign lesion is not as high as was feared.

  10. ATM, radiation, and the risk of second primary breast cancer.

    PubMed

    Bernstein, Jonine L; Concannon, Patrick

    2017-07-27

    It was first suggested more than 40 years ago that heterozygous carriers for the human autosomal recessive disorder Ataxia-Telangiectasia (A-T) might also be at increased risk for cancer. Subsequent studies have identified the responsible gene, Ataxia-Telangiectasia Mutated (ATM), characterized genetic variation at this locus in A-T and a variety of different cancers, and described the functions of the ATM protein with regard to cellular DNA damage responses. However, an overall model of how ATM contributes to cancer risk, and in particular, the role of DNA damage in this process, remains lacking. This review considers these questions in the context of contralateral breast cancer (CBC). Heterozygous carriers of loss of function mutations in ATM that are A-T causing, are at increased risk of breast cancer. However, examination of a range of genetic variants, both rare and common, across multiple cancers, suggests that ATM may have additional effects on cancer risk that are allele-dependent. In the case of CBC, selected common alleles at ATM are associated with a reduced incidence of CBC, while other rare and predicted deleterious variants may act jointly with radiation exposure to increase risk. Further studies that characterize germline and somatic ATM mutations in breast cancer and relate the detected genetic changes to functional outcomes, particularly with regard to radiation responses, are needed to gain a complete picture of the complex relationship between ATM, radiation and breast cancer.

  11. Current clinical trials testing combinations of immunotherapy and radiation.

    PubMed

    Crittenden, Marka; Kohrt, Holbrook; Levy, Ronald; Jones, Jennifer; Camphausen, Kevin; Dicker, Adam; Demaria, Sandra; Formenti, Silvia

    2015-01-01

    Preclinical evidence of successful combinations of ionizing radiation with immunotherapy has inspired testing the translation of these results to the clinic. Interestingly, the preclinical work has consistently predicted the responses encountered in clinical trials. The first example came from a proof-of-principle trial started in 2001 that tested the concept that growth factors acting on antigen-presenting cells improve presentation of tumor antigens released by radiation and induce an abscopal effect. Granulocyte-macrophage colony-stimulating factor was administered during radiotherapy to a metastatic site in patients with metastatic solid tumors to translate evidence obtained in a murine model of syngeneic mammary carcinoma treated with cytokine FLT-3L and radiation. Subsequent clinical availability of vaccines and immune checkpoint inhibitors has triggered a wave of enthusiasm for testing them in combination with radiotherapy. Examples of ongoing clinical trials are described in this report. Importantly, most of these trials include careful immune monitoring of the patients enrolled and will generate important data about the proimmunogenic effects of radiation in combination with a variety of immune modulators, in different disease settings. Results of these studies are building a platform of evidence for radiotherapy as an adjuvant to immunotherapy and encourage the growth of this novel field of radiation oncology.

  12. Current Clinical Trials Testing Combinations of Immunotherapy and Radiation

    PubMed Central

    Crittenden, M.; Kohrt, H.; Levy, R.; Jones, J.; Camphausen, K.; Dicker, A.; Demaria, S.; Formenti, S.

    2014-01-01

    Preclinical evidence of successful combinations of ionizing radiation with immunotherapy has inspired testing the translation of these results to the clinic. Interestingly, the preclinical work has consistently predicted the responses encountered in clinical trials. The first example came from a proof-of-principle trial started in 2001 that tested the concept that growth factors acting on antigen-presenting cells improve presentation of tumor antigens released by radiation and induce an abscopal effect. Granulocyte-macrophage colony-stimulating factor was administered during radiotherapy to a metastatic site in patients with metastatic solid tumors to translate evidence obtained in a murine model of syngeneic mammary carcinoma treated with cytokine FLT-3L and radiation. Subsequent clinical availability of vaccines and immune checkpoint inhibitors has triggered a wave of enthusiasm for testing them in combination with radiotherapy. Examples of ongoing clinical trials are described in this report. Importantly, these trials include careful immune monitoring of the patients enrolled and will generate important data about the proimmunogenic effects of radiation in combination with a variety of immune modulators in different disease settings. Results of these studies are building a platform of evidence for radiotherapy as an adjuvant to immunotherapy and encourage the growth of this novel field of radiation oncology. PMID:25481267

  13. [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.

  14. IAEA experience in communicating radiation risks through the RPOP website.

    PubMed

    Rehani, M M; Holmberg, O

    2015-07-01

    The authors report here their successful experience of communicating information to health professionals, patients and the public on benefits and risks of ionising radiation in medical applications. The approaches used have been based on giving importance to clinical benefits against risks, as well as safety in use against risk of use. Communicating brief messages against catchy questions with positive and pragmatic approach resulted in making website on radiation protection of patients (RPOP) as the top website of the world in this area. Credibility of information has been maintained. The results show immense outreach in 213 countries/territories. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. On the ideality factor of the radiative recombination current in semiconductor light-emitting diodes

    SciTech Connect

    Lee, Gyeong Won; Shim, Jong-In; Shin, Dong-Soo

    2016-07-18

    While there have been many discussions on the standard Si pn-diodes, little attention has been paid and confusion still arises on the ideality factor of the radiative recombination current in semiconductor light-emitting diodes (LEDs). In this letter, we theoretically demonstrate and experimentally confirm by using blue and infrared semiconductor LEDs that the ideality factor of the radiative recombination current is unity especially for low-current-density ranges. We utilize the data of internal quantum efficiency measured by the temperature-dependent electroluminescence to separate the radiative current component from the total current.

  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. Fears, Feelings, and Facts: Interactively Communicating Benefits and Risks of Medical Radiation With Patients

    PubMed Central

    Dauer, Lawrence T.; Thornton, Raymond H.; Hay, Jennifer L.; Balter, Rochelle; Williamson, Matthew J.; St. Germain, Jean

    2013-01-01

    OBJECTIVE As public awareness of medical radiation exposure increases, there has been heightened awareness among patients and physicians of the importance of holistic benefit-and-risk discussions in shared medical decision making. CONCLUSION We examine the rationale for informed consent and risk communication, draw on the literature on the psychology of radiation risk communication to increase understanding, examine methods commonly used to communicate radiation risk, and suggest strategies for improving communication about medical radiation benefits and risk. PMID:21427321

  18. Radiation exposure risk to the surgeon during operative angiography

    SciTech Connect

    Ramalanjaona, G.R.; Pearce, W.H.; Ritenour, E.R.

    1986-09-01

    Intraoperative angiography has become an essential adjunct to reconstructive vascular surgery. Therefore, radiation exposure and its potential risks to the performing surgeon need to be known. To study this, we designed experimental and clinical tests quantifying the radiation exposure to the surgeon during different intraoperative angiograms. Radiation exposure to various parts of the surgeon's body was quantified by thermoluminescence dosimetry. During each exposure a surgeon standing one foot from the x-ray tube received an absorbed dose equivalent to 0.24 to 1.4 millirems, which is about half that of an intraoperative cholangiogram. With 5000 millirems considered the maximum permissible dose, this would imply that an upper limit of about 3500 intraoperative angiograms each year (68 each week) could be performed safely. Comparatively, abdominal angiography carried the most significant risk (p = 0.01) and peripheral angiography was the least hazardous. Fluoroscopy increased radiation exposure more than four times that of nonfluoroscopic procedures (p = 0.05). The surgeon's extremities received the greatest dose, followed by the eyes and neck, suggesting the need for individual monitoring devices for those parts to be worn by surgeons who perform operative angiograms more frequently than average. Our study indicates that the radiation dose received by the surgeon during operative angiography, especially that of peripheral vessels, is minimal. Operative arteriography is not only a simple and readily available diagnostic tool, but it is quite a safe procedure if applied correctly.

  19. Space Radiation Risk Assessment for Future Lunar Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Ponomarev, Artem; Atwell, Bill; Cucinotta, Francis A.

    2007-01-01

    For lunar exploration mission design, radiation risk assessments require the understanding of future space radiation environments in support of resource management decisions, operational planning, and a go/no-go decision. The future GCR flux was estimated as a function of interplanetary deceleration potential, which was coupled with the estimated neutron monitor rate from the Climax monitor using a statistical model. A probability distribution function for solar particle event (SPE) occurrence was formed from proton fluence measurements of SPEs occurred during the past 5 solar cycles (19-23). Large proton SPEs identified from impulsive nitrate enhancements in polar ice for which the fluences are greater than 2 10(exp 9) protons/sq cm for energies greater than 30 MeV, were also combined to extend the probability calculation for high level of proton fluences. The probability with which any given proton fluence level of a SPE will be exceeded during a space mission of defined duration was then calculated. Analytic energy spectra of SPEs at different ranks of the integral fluences were constructed over broad energy ranges extending out to GeV, and representative exposure levels were analyzed at those fluences. For the development of an integrated strategy for radiation protection on lunar exploration missions, effective doses at various points inside a spacecraft were calculated with detailed geometry models representing proposed transfer vehicle and habitat concepts. Preliminary radiation risk assessments from SPE and GCR were compared for various configuration concepts of radiation shelter in exploratory-class spacecrafts.

  20. Numerical Techniques for Coupled Ring Current - Radiation Belts Modelling

    NASA Astrophysics Data System (ADS)

    Aseev, Nikita; Shprits, Yuri; Kellerman, Adam; Drozdov, Alexander

    2016-04-01

    The dynamics of electrons in the Earth's radiation belts can be described by the Fokker-Planck equation, which includes radial and local diffusion processes. The Versatile Electron Radiation Belt (VERB) code was developed to solve the Fokker-Planck equation for electron PSD. It incorporates a range of numerical techniques, which are appropriate for this purpose. The code has been recently extended to include convection and now solves the convection-diffusion problem in 4D. This report is devoted to several numerical algorithms for modeling of the Earth's radiation belts. We concentrate on a comparison of 3rd and 9th-order schemes for solution of an advection problem, and show some results on the basis of the numerical solution of the local diffusion problem including mixed terms in 2D. Recent 4D modeling of storm events using the VERB-4D code will be also presented.

  1. Current knowledge on radon risk: implications for practical radiation protection? radon workshop, 1/2 December 2015, Bonn, BMUB (Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit; Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety).

    PubMed

    Müller, Wolfgang-Ulrich; Giussani, Augusto; Rühm, Werner; Lecomte, Jean-Francois; Harrison, John; Kreuzer, Michaela; Sobotzki, Christina; Breckow, Joachim

    2016-08-01

    ICRP suggested a strategy based on the distinction between a protection approach for dwellings and one for workplaces in the previous recommendations on radon. Now, the Commission recommends an integrated approach for the protection against radon exposure in all buildings irrespective of their purpose and the status of their occupants. The strategy of protection in buildings, implemented through a national action plan, is based on the application of the optimisation principle below a derived reference level in concentration (maximum 300 Bq m(-3)). A problem, however, arises that due to new epidemiological findings and application of dosimetric models, ICRP 115 (Ann ICRP 40, 2010) presents nominal probability coefficients for radon exposure that are approximately by a factor of 2 larger than in the former recommendations of ICRP 65 (Ann ICRP 23, 1993). On the basis of the so-called epidemiological approach and the dosimetric approach, the doubling of risk per unit exposure is represented by a doubling of the dose coefficients, while the risk coefficient of ICRP 103 (2007) remains unchanged. Thus, an identical given radon exposure situation with the new dose coefficients would result in a doubling of dose compared with the former values. This is of serious conceptual implications. A possible solution of this problem was presented during the workshop.

  2. [Current status and limitation of particle radiation therapy].

    PubMed

    Ogino, Takashi

    2009-11-01

    Almost 9,000 patients have been treated by particle radiation therapy as a highly advanced medical technology in Japan, and definitive evaluation of this technology might now be possible. The process of approval of medical equipment, the law of medical technologists, and the law of medicine for particle radiation therapy have also been prepared. Number of facilities is expected to increase, and time has come that the fee of this medicine would cover by social insurance. Much debate, however, has been published in English journals upon proton therapy. The National Cancer Institute has started to support clinical trials in the United States. In Japan, however, research funding is still quite small.

  3. 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

  4. 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.

  5. 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.

  6. Review of radiation risks from computed tomography: essentials for the pediatric surgeon.

    PubMed

    Rice, Henry E; Frush, Donald P; Farmer, Diana; Waldhausen, John H

    2007-04-01

    Over the past several years, increasing attention has been focused on the potential for radiation exposure from computed tomography (CT) for inducing the development of cancers. An understanding of these issues is important for the practice of pediatric surgery. Medline based clinical review of current medical literature of the risks for the induction of cancers by CT. Data includes estimates of cancer risk from computer models, epidemiologic data from survivors of atomic bomb radiation exposure, and consensus opinions from expert panels. Review of scientific evidence demonstrates varied opinions, but consensus suggests there may be a potential for an increased risk of cancer from low level radiation exposure such as from CT. These calculations suggest that there may be as high as 1 fatal cancer for every 1000 CT scans performed in a young child. Pediatric surgeons should be aware of the potential risks of CT. Minimizing the radiation risks of CT is a complex endeavor, and will require investments from pediatric surgeons as well as pediatric radiologists.

  7. Task-based measures of image quality and their relation to radiation dose and patient risk

    PubMed Central

    Barrett, Harrison H.; Myers, Kyle J.; Hoeschen, Christoph; Kupinski, Matthew A.; Little, Mark P.

    2015-01-01

    The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discussed. Then various standard methods for specifying radiation dose are reviewed and related to the mean number of photons in the image and hence to image quality. Current knowledge of the relation between local radiation dose and the risk of various adverse effects is summarized, and some graphical depictions of the tradeoffs between image quality and risk are introduced. Then various dose-reduction strategies are discussed in terms of their effect on task-based measures of image quality. PMID:25564960

  8. Impact of rocket propulsion technology on the radiation risk in missions to Mars

    NASA Astrophysics Data System (ADS)

    Durante, M.; Bruno, C.

    2010-10-01

    Exposure to cosmic radiation is today acknowledged as a major obstacle to human missions to Mars. In fact, in addition to the poor knowledge on the late effects of heavy ions in the cosmic rays, simple countermeasures are apparently not available. Shielding is indeed very problematic in space, because of mass problems and the high-energy of the cosmic rays, and radio-protective drugs or dietary supplements are not effective. However, the simplest countermeasure for reducing radiation risk is to shorten the duration time, particularly the transit time to Mars, where the dose rate is higher than on the planet surface. Here we show that using nuclear electric propulsion (NEP) rockets, the transit time could be substantially reduced to a point where radiation risk could be considered acceptable even with the current uncertainty on late effects.

  9. 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.

  10. 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.

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

    PubMed Central

    Hendry, Jolyon H; Simon, Steven L; Wojcik, Andrzej; Sohrabi, Mehdi; Burkart, Werner; Cardis, Elisabeth; Laurier, Dominique; Tirmarche, Margot; Hayata, Isamu

    2014-01-01

    Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of 222Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case–control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case–control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors. PMID:19454802

  12. 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.

  13. 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.

    2015-01-01

    Possible acute and late risks to the central nervous system (CNS) from galactic cosmic rays (GCR) and solar particle events (SPE) are a documented concern for human exploration of space. Acute CNS risks include: altered cognitive function, reduced motor function, and behavioral changes, all of which may affect performance and human health. Late CNS risks 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 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.

  14. Comparison of radiation exposure and associated radiation-induced cancer risks from mammography and molecular imaging of the breast.

    PubMed

    O'Connor, Michael K; Li, Hua; Rhodes, Deborah J; Hruska, Carrie B; Clancy, Conor B; Vetter, Richard J

    2010-12-01

    Recent studies have raised concerns about exposure to low-dose ionizing radiation from medical imaging procedures. Little has been published regarding the relative exposure and risks associated with breast imaging techniques such as breast specific gamma imaging (BSGI), molecular breast imaging (MBI), or positron emission mammography (PEM). The purpose of this article was to estimate and compare the risks of radiation-induced cancer from mammography and techniques such as PEM, BSGI, and MBI in a screening environment. The authors used a common scheme for all estimates of cancer incidence and mortality based on the excess absolute risk model from the BEIR VII report. The lifetime attributable risk model was used to estimate the lifetime risk of radiation-induced breast cancer incidence and mortality. All estimates of cancer incidence and mortality were based on a population of 100 000 females followed from birth to age 80 and adjusted for the fraction that survives to various ages between 0 and 80. Assuming annual screening from ages 40 to 80 and from ages 50 to 80, the cumulative cancer incidence and mortality attributed to digital mammography, screen-film mammography, MBI, BSGI, and PEM was calculated. The corresponding cancer incidence and mortality from natural background radiation was calculated as a useful reference. Assuming a 15%-32% reduction in mortality from screening, the benefit/risk ratio for the different imaging modalities was evaluated. Using conventional doses of 925 MBq Tc-99m sestamibi for MBI and BSGI and 370 MBq F-18 FDG for PEM, the cumulative cancer incidence and mortality were found to be 15-30 times higher than digital mammography. The benefit/risk ratio for annual digital mammography was >50:1 for both the 40-80 and 50-80 screening groups, but dropped to 3:1 for the 40-49 age group. If the primary use of MBI, BSGI, and PEM is in women with dense breast tissue, then the administered doses need to be in the range 75-150 MBq for Tc-99m

  15. Comparison of radiation exposure and associated radiation-induced cancer risks from mammography and molecular imaging of the breast1

    PubMed Central

    O’Connor, Michael K.; Li, Hua; Rhodes, Deborah J.; Hruska, Carrie B.; Clancy, Conor B.; Vetter, Richard J.

    2010-01-01

    Purpose: Recent studies have raised concerns about exposure to low-dose ionizing radiation from medical imaging procedures. Little has been published regarding the relative exposure and risks associated with breast imaging techniques such as breast specific gamma imaging (BSGI), molecular breast imaging (MBI), or positron emission mammography (PEM). The purpose of this article was to estimate and compare the risks of radiation-induced cancer from mammography and techniques such as PEM, BSGI, and MBI in a screening environment. Methods: The authors used a common scheme for all estimates of cancer incidence and mortality based on the excess absolute risk model from the BEIR VII report. The lifetime attributable risk model was used to estimate the lifetime risk of radiation-induced breast cancer incidence and mortality. All estimates of cancer incidence and mortality were based on a population of 100 000 females followed from birth to age 80 and adjusted for the fraction that survives to various ages between 0 and 80. Assuming annual screening from ages 40 to 80 and from ages 50 to 80, the cumulative cancer incidence and mortality attributed to digital mammography, screen-film mammography, MBI, BSGI, and PEM was calculated. The corresponding cancer incidence and mortality from natural background radiation was calculated as a useful reference. Assuming a 15%–32% reduction in mortality from screening, the benefit∕risk ratio for the different imaging modalities was evaluated. Results: Using conventional doses of 925 MBq Tc-99m sestamibi for MBI and BSGI and 370 MBq F-18 FDG for PEM, the cumulative cancer incidence and mortality were found to be 15–30 times higher than digital mammography. The benefit∕risk ratio for annual digital mammography was >50:1 for both the 40–80 and 50–80 screening groups, but dropped to 3:1 for the 40–49 age group. If the primary use of MBI, BSGI, and PEM is in women with dense breast tissue, then the administered doses need to

  16. Comparison of radiation exposure and associated radiation-induced cancer risks from mammography and molecular imaging of the breast

    SciTech Connect

    O'Connor, Michael K.; Li Hua; Rhodes, Deborah J.; Hruska, Carrie B.; Clancy, Conor B.; Vetter, Richard J.

    2010-12-15

    Purpose: Recent studies have raised concerns about exposure to low-dose ionizing radiation from medical imaging procedures. Little has been published regarding the relative exposure and risks associated with breast imaging techniques such as breast specific gamma imaging (BSGI), molecular breast imaging (MBI), or positron emission mammography (PEM). The purpose of this article was to estimate and compare the risks of radiation-induced cancer from mammography and techniques such as PEM, BSGI, and MBI in a screening environment. Methods: The authors used a common scheme for all estimates of cancer incidence and mortality based on the excess absolute risk model from the BEIR VII report. The lifetime attributable risk model was used to estimate the lifetime risk of radiation-induced breast cancer incidence and mortality. All estimates of cancer incidence and mortality were based on a population of 100 000 females followed from birth to age 80 and adjusted for the fraction that survives to various ages between 0 and 80. Assuming annual screening from ages 40 to 80 and from ages 50 to 80, the cumulative cancer incidence and mortality attributed to digital mammography, screen-film mammography, MBI, BSGI, and PEM was calculated. The corresponding cancer incidence and mortality from natural background radiation was calculated as a useful reference. Assuming a 15%-32% reduction in mortality from screening, the benefit/risk ratio for the different imaging modalities was evaluated. Results: Using conventional doses of 925 MBq Tc-99m sestamibi for MBI and BSGI and 370 MBq F-18 FDG for PEM, the cumulative cancer incidence and mortality were found to be 15-30 times higher than digital mammography. The benefit/risk ratio for annual digital mammography was >50:1 for both the 40-80 and 50-80 screening groups, but dropped to 3:1 for the 40-49 age group. If the primary use of MBI, BSGI, and PEM is in women with dense breast tissue, then the administered doses need to be in the range

  17. A comparative study of space radiation organ doses and associated cancer risks using PHITS and HZETRN.

    PubMed

    Bahadori, Amir A; Sato, Tatsuhiko; Slaba, Tony C; Shavers, Mark R; Semones, Edward J; Van Baalen, Mary; Bolch, Wesley E

    2013-10-21

    NASA currently uses one-dimensional deterministic transport to generate values of the organ dose equivalent needed to calculate stochastic radiation risk following crew space exposures. In this study, organ absorbed doses and dose equivalents are calculated for 50th percentile male and female astronaut phantoms using both the NASA High Charge and Energy Transport Code to perform one-dimensional deterministic transport and the Particle and Heavy Ion Transport Code System to perform three-dimensional Monte Carlo transport. Two measures of radiation risk, effective dose and risk of exposure-induced death (REID) are calculated using the organ dose equivalents resulting from the two methods of radiation transport. For the space radiation environments and simplified shielding configurations considered, small differences (<8%) in the effective dose and REID are found. However, for the galactic cosmic ray (GCR) boundary condition, compensating errors are observed, indicating that comparisons between the integral measurements of complex radiation environments and code calculations can be misleading. Code-to-code benchmarks allow for the comparison of differential quantities, such as secondary particle differential fluence, to provide insight into differences observed in integral quantities for particular components of the GCR spectrum.

  18. Current Radiation Issues for Programmable Elements and Devices

    NASA Technical Reports Server (NTRS)

    Katz, R.; Wang, J. J.; Koga, R.; LaBel, A.; McCollum, J.; Brown, R.; Reed, R. A.; Cronquist, B.; Crain, S.; Scott, T.; Paolini, W.; Sin, B.

    1998-01-01

    State of the an programmable devices are utilizing advanced processing technologies, non-standard circuit structures, and unique electrical elements in commercial-off-the-shelf (COTS)-based, high-performance devices. This paper will discuss that the above factors, coupled with the systems application environment, have a strong interplay that affect the radiation hardness of programmable devices and have resultant system impacts in (1) reliability of the unprogrammed, biased antifuse for heavy ions (rupture), (2) logic upset manifesting itself as clock upset, and (3) configuration upset. General radiation characteristics of advanced technologies are examined and manufacturers' modifications to their COTS-based and their impact on future programmable devices will be analyzed.

  19. Terahertz Radiation Driven Chiral Edge Currents in Graphene

    NASA Astrophysics Data System (ADS)

    Karch, J.; Drexler, C.; Olbrich, P.; Fehrenbacher, M.; Hirmer, M.; Glazov, M. M.; Tarasenko, S. A.; Ivchenko, E. L.; Birkner, B.; Eroms, J.; Weiss, D.; Yakimova, R.; Lara-Avila, S.; Kubatkin, S.; Ostler, M.; Seyller, T.; Ganichev, S. D.

    2011-12-01

    We observe photocurrents induced in single-layer graphene samples by illumination of the graphene edges with circularly polarized terahertz radiation at normal incidence. The photocurrent flows along the sample edges and forms a vortex. Its winding direction reverses by switching the light helicity from left to right handed. We demonstrate that the photocurrent stems from the sample edges, which reduce the spatial symmetry and result in an asymmetric scattering of carriers driven by the radiation electric field. The developed theory based on Boltzmann’s kinetic equation is in a good agreement with the experiment. We show that the edge photocurrents can be applied for determination of the conductivity type and the momentum scattering time of the charge carriers in the graphene edge vicinity.

  20. 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

  1. Study warns of radiation risk in medical imaging

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2009-10-01

    A study of a million US patients suggests that some who undergo medical imaging could be exposed to more ionizing radiation than those who work with radioactive materials in nuclear power plants. The study, reported in The New England Journal of Medicine (361 849), implies that current exposure to radiation from conventional X-ray equipment as well as computed tomography (CT) and positron-emission tomography (PET) scanners could lead to tens of thousands of extra cases of cancer in the US alone.

  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. The Magnetic and Shielding Effects of Ring Current on Radiation Belt Dynamics

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching

    2012-01-01

    The ring current plays many key roles in controlling magnetospheric dynamics. A well-known example is the magnetic depression produced by the ring current, which alters the drift paths of radiation belt electrons and may cause significant electron flux dropout. Little attention is paid to the ring current shielding effect on radiation belt dynamics. A recent simulation study that combines the Comprehensive Ring Current Model (CRCM) with the Radiation Belt Environment (RBE) model has revealed that the ring current-associated shielding field directly and/or indirectly weakens the relativistic electron flux increase during magnetic storms. In this talk, we will discuss how ring current magnetic field and electric shielding moderate the radiation belt enhancement.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. Genetic risks associated with radiation exposures during space flight

    SciTech Connect

    Grahn, D.

    1983-01-01

    Although the genetic risks of space radiation do not pose a significant hazard to the general population, the risks may be very important to the individual astronaut. The present paper summarizes some experimental results on the induction of dominant lethal mutations and chromosomal damage in the first generation which may be used in the prediction of the genetic risks of radiation exposures of space crews. Young adult male mice were exposed to single, weekly and continuous doses of gamma rays, neutrons in single doses and weekly exposures and continuous doses of Pu-239 alpha particles. Evaluation of fetal survival rates in females mated to the exposed males shows the mutation rate in individuals exposed to gamma rays to decline as the exposure period is prolonged and the dose rate is reduced, while the response to neutrons is in the opposite direction. Cytological determinations show the rate of balanced chromosomal translocations to drop as gamma ray exposures change from one-time to continuous, however little or no dose rate effect is seen with neutron radiation and alpha particle exposure shows no regular dose-response. Based on the above results, it is predicted that the rate of dominant mutations and transmissible chromosome aberrations in astronauts on a 100-day mission will increase by 4.5 to 41.25 percent over the spontaneous rate. 35 references.

  12. 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

  13. Imaging strategies to reduce the risk of radiation in CT studies, including selective substitution with MRI.

    PubMed

    Semelka, Richard C; Armao, Diane M; Elias, Jorge; Huda, Walter

    2007-05-01

    "When one admits that nothing is certain one must, I think, also admit that some things are much more nearly certain than others." Bertrand Russell (1872-1970) Computed tomography (CT) is one of the largest contributors to man-made radiation doses in medical populations. CT currently accounts for over 60 million examinations in the United States, and its use continues to grow rapidly. The principal concern regarding radiation exposure is that the subject may develop malignancies. For this systematic review we searched journal publications in MEDLINE (1966-2006) using the terms "CT," "ionizing radiation," "cancer risks," "MRI," and "patient safety." We also searched major reports issued from governmental U.S. and world health-related agencies. Many studies have shown that organ doses associated with routine diagnostic CT scans are similar to the low-dose range of radiation received by atomic-bomb survivors. The FDA estimates that a CT examination with an effective dose of 10 mSv may be associated with an increased chance of developing fatal cancer for approximately one patient in 2000, whereas the BEIR VII lifetime risk model predicts that with the same low-dose radiation, approximately one individual in 1000 will develop cancer. There are uncertainties in the current radiation risk estimates, especially at the lower dose levels encountered in CT. To address what should be done to ensure patient safety, in this review we discuss the "as low as reasonably achievable" (ALARA) principle, and the use of MRI as an alternative to CT. (c) 2007 Wiley-Liss, Inc.

  14. Summary of current radiation dosimetry results on manned spacecraft.

    PubMed

    Benton, E V

    1984-01-01

    Measurements of radiation exposures aboard manned space flights of various altitudes, orbital inclinations and durations were performed by means of passive radiation detectors, thermoluminescent detectors (TLD's), and in some cases by active electronic counters. The TLD's and electronic counters covered the lower portion of the LET (linear energy transfer) spectra, while the nuclear track detectors measured high-LET produced by HZE particles. In Spacelab (SL-1), TLD's recorded a range of 102 to 190-millirad, yielding an average low-LET dose rate of 11.2 mrad per day inside the module, about twice the dose rate measured on previous space shuttle flights. Because of a higher inclination of the SL-1 orbit (57 degrees versus 28.5 degrees for previous shuttle flights), substantial fluxes of highly ionizing HZE particles were also observed, yielding an overall average mission dose-equivalent of about 135 millirem, about three times higher than measured an previous shuttle missions. A dose rate more than an order of magnitude higher than for any other space shuttle light was obtained for mission STS-41C, reflecting the highest orbital altitude to date of 519 km.

  15. 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.

  16. Current issues and perspectives in food safety and risk assessment.

    PubMed

    Eisenbrand, G

    2015-12-01

    In this review, current issues and opportunities in food safety assessment are discussed. Food safety is considered an essential element inherent in global food security. Hazard characterization is pivotal within the continuum of risk assessment, but it may be conceived only within a very limited frame as a true alternative to risk assessment. Elucidation of the mode of action underlying a given hazard is vital to create a plausible basis for human toxicology evaluation. Risk assessment, to convey meaningful risk communication, must be based on appropriate and reliable consideration of both exposure and mode of action. New perspectives, provided by monitoring human exogenous and endogenous exposure biomarkers, are considered of great promise to support classical risk extrapolation from animal toxicology.

  17. The impact of solar particle events on radiation risk for human explorers of Mars

    NASA Astrophysics Data System (ADS)

    Gorguinpour, Camron Saul

    This project has examined one specific issue facing human explorers at Mars -- radiation dose from solar particle events (SPEs). While the issue is specific, the work involved in carrying out this study has been truly multidisciplinary. From space physics to modeling the Martian atmosphere to assessing radiation risk to humans, a lot of ground is covered. At each point along the way, efforts were made to clarify the science and assumptions used to derive quantitative estimates and draw meaningful conclusions. The data and analyses provided in this project represent the most comprehensive study of SPE's at a planetary body other than Earth. The analysis includes dose estimates from galactic cosmic radiation. The specific aims of this project are to: (1) Establish a methodology for estimating the fluence of energetic particles at Mars from SPEs; (2) Establish a predictive model to estimate the frequency of SPE occurrence and cumulative SPE fluence received at Mars, as a function of the Solar Cycle; (3) Develop a model to estimate the fluence of energetic particles from SPEs on the Martian surface; (4) Estimate and assess the radiation dose on the Martian surface from SPEs, as compared to galactic cosmic radiation (GCR); and (5) Assess the viability of various types of shielding and mission profiles to mitigate the radiation risk to human explorers on the Martian surface. Some of the conclusions drawn from this study include: (1) The MCP detector onboard MGS ER (and presumably other spacecraft) can serve as an effective detector for high-energy ionizing radiation. (2) Though more work is necessary, it is possible to estimate future solar activity at Earth and Mars based on current solar observations. (3) Spectral information from SPE's at Mars is required to thoroughly assess the radiation environment on the Martian surface. (4) An unshielded astronaut on the Martian surface may face long-term and acute radiation risk from SPE's, depending on the likelihood of their

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Genetic radiation risks: a neglected topic in the low dose debate

    PubMed Central

    2016-01-01

    Objectives To investigate the accuracy and scientific validity of the current very low risk factor for hereditary diseases in humans following exposures to ionizing radiation adopted by the United Nations Scientific Committee on the Effects of Atomic Radiation and the International Commission on Radiological Protection. The value is based on experiments on mice due to reportedly absent effects in the Japanese atomic bomb (Abomb) survivors. Methods To review the published evidence for heritable effects after ionising radiation exposures particularly, but not restricted to, populations exposed to contamination from the Chernobyl accident and from atmospheric nuclear test fallout. To make a compilation of findings about early deaths, congenital malformations, Down’s syndrome, cancer and other genetic effects observed in humans after the exposure of the parents. To also examine more closely the evidence from the Japanese A-bomb epidemiology and discuss its scientific validity. Results Nearly all types of hereditary defects were found at doses as low as one to 10 mSv. We discuss the clash between the current risk model and these observations on the basis of biological mechanism and assumptions about linear relationships between dose and effect in neonatal and foetal epidemiology. The evidence supports a dose response relationship which is non-linear and is either biphasic or supralinear (hogs-back) and largely either saturates or falls above 10 mSv. Conclusions We conclude that the current risk model for heritable effects of radiation is unsafe. The dose response relationship is non-linear with the greatest effects at the lowest doses. Using Chernobyl data we derive an excess relative risk for all malformations of 1.0 per 10 mSv cumulative dose. The safety of the Japanese A-bomb epidemiology is argued to be both scientifically and philosophically questionable owing to errors in the choice of control groups, omission of internal exposure effects and assumptions about

  3. Development of Graphical User Interface for ARRBOD (Acute Radiation Risk and BRYNTRN Organ Dose Projection)

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Hu, Shaowen; Nounu, Hatem N.; Cucinotta, Francis A.

    2010-01-01

    The space radiation environment, particularly solar particle events (SPEs), poses the risk of acute radiation sickness (ARS) to humans; and organ doses from SPE exposure may reach critical levels during extra vehicular activities (EVAs) or within lightly shielded spacecraft. NASA has developed an organ dose projection model using the BRYNTRN with SUMDOSE computer codes, and a probabilistic model of Acute Radiation Risk (ARR). The codes BRYNTRN and SUMDOSE, written in FORTRAN, are a Baryon transport code and an output data processing code, respectively. The ARR code is written in C. The risk projection models of organ doses and ARR take the output from BRYNTRN as an input to their calculations. BRYNTRN code operation requires extensive input preparation. With a graphical user interface (GUI) to handle input and output for BRYNTRN, the response models can be connected easily and correctly to BRYNTRN in friendly way. A GUI for the Acute Radiation Risk and BRYNTRN Organ Dose (ARRBOD) projection code provides seamless integration of input and output manipulations, which are required for operations of the ARRBOD modules: BRYNTRN, SUMDOSE, and the ARR probabilistic response model. The ARRBOD GUI is intended for mission planners, radiation shield designers, space operations in the mission operations directorate (MOD), and space biophysics researchers. The ARRBOD GUI will serve as a proof-of-concept example for future integration of other human space applications risk projection models. The current version of the ARRBOD GUI is a new self-contained product and will have follow-on versions, as options are added: 1) human geometries of MAX/FAX in addition to CAM/CAF; 2) shielding distributions for spacecraft, Mars surface and atmosphere; 3) various space environmental and biophysical models; and 4) other response models to be connected to the BRYNTRN. The major components of the overall system, the subsystem interconnections, and external interfaces are described in this

  4. Whether ionizing radiation is a risk factor for schizophrenia spectrum disorders?

    PubMed

    Loganovsky, Konstantin N; Volovik, Sergij V; Manton, Kenneth G; Bazyka, Dimitry A; Flor-Henry, Pierre

    2005-01-01

    The neural diathesis-stressor hypothesis of schizophrenia, where neurobiological genetic predisposition to schizophrenia can be provoked by environmental stressors is considered as a model of the effects of exposure to ionizing radiation. Analysis of information from electronic databases (MEDLINE, PsycINFO, EMBASE, Current Contents, Elsevier BIOBASE) and hand-made search was carried out. There are comparable reports on increases in schizophrenia spectrum disorders following exposure to ionizing radiation as a result of atomic bombing, nuclear weapons testing, the Chernobyl accident, environmental contamination by radioactive waste, radiotherapy, and also in areas with high natural radioactive background. The results of experimental radioneurobiological studies support the hypothesis of schizophrenia as a neurodegenerative disease. Exposure to ionizing radiation causes brain damage with limbic (cortical-limbic) system dysfunction and impairment of informative processes at the molecular level that can trigger schizophrenia in predisposed individuals or cause schizophrenia-like disorders. It is supposed that ionizing radiation can be proposed as a risk factor for schizophrenia spectrum disorders. The hypothesis that ionizing radiation is a risk factor for schizophrenia spectrum disorders can be tested using data from the Chernobyl accident aftermath. Implementation of a study on schizophrenia spectrum disorders in Chernobyl accident victims is of significance for both clinical medicine and neuroscience.

  5. [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.

  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. 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.

  8. Musculoskeletal disorder risk during automotive assembly: current vs. seated

    PubMed Central

    Ferguson, Sue A.; Marras, William S.; Allread, W. Gary; Knapik, Gregory G.; Splittstoesser, Riley E.

    2013-01-01

    Musculoskeletal disorder risk was assessed during automotive assembly processes. The risk associated with current assembly processes was compared to using a cantilever chair intervention. Spine loads and normalized shoulder muscle activity were evaluated during assembly in eight regions of the vehicle. Eight interior cabin regions of the vehicle were classified by reach distance, height from vehicle floor and front to back. The cantilever chair intervention tool was most effective in the far reach regions regardless of the height. In the front far reach regions both spine loads and normalized shoulder muscle activity levels were reduced. In the middle and close reach regions spine loads were reduced, however, shoulder muscle activity was not, thus an additional intervention would be necessary to reduce shoulder risk. In the back far reach region, spine loads were not significantly different between the current and cantilever chair conditions. Thus, the effectiveness of the cantilever chair was dependent on the region of the vehicle. PMID:22036450

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Modulating sub-THz radiation with current in superconducting metamaterial.

    PubMed

    Savinov, V; Fedotov, V A; Anlage, S M; de Groot, P A J; Zheludev, N I

    2012-12-14

    We show that subterahertz transmission of the superconducting metamaterial, an interlinked two-dimensional network of subwavelength resonators connected by a continuous superconducting wire loop, can be dynamically modulated by passing electrical current through it. We have identified the main mechanisms of modulation that correspond to the suppression of the superconductivity in the network by magnetic field and heat dissipation. Using the metamaterial fabricated from thin niobium film, we were able to demonstrate a transmission modulation depth of up to 45% and a bandwidth of at least 100 kHz. The demonstrated approach may be implemented with other superconducting materials at frequencies below the superconducting gap in the THz and subterahertz bands.

  16. 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.

  17. 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.

  18. Numerical modeling investigation of radiation stress in coastal wave-current coupling

    NASA Astrophysics Data System (ADS)

    Guan, Changlong; Li, Rui

    2014-05-01

    It is believed that the radiation stress is the main driving force for nearshore wave-induced currents. So far several theoretical formulas of radiation stress have been proposed, among which the vertical structures differ considerably. A numerical wave flume (NWF) have been established on the basis of the CFD software, and applied to simulate the wave motion in various shallow water topography with different incident waves. The results from the NWF is used to analyze the features of radiation stress. It is found, that the vertical integral of the radiation stress is agreeably consistent with the well-known classical result by Longuet-Higgins and Stewart (1964), while the vertical structure of the radiation stress is discontinuous at the surface where the maximum exists, which can be better characterized with the formula by Mellor (2008). The effects of radiation stress and wave roller are implemented in a coupled SWAN-POM model, so that the coupled model is able to simulate the wave setup and wave-induced current. The numerical modeling results have been verified by the field measurements. It is shown that the modelled wave setup corresponding to various radiation stress formulas is well in agreement with the field observation. This means the modeled wave setup is dependent on the vertical integral of radiation stress rather than the vertical structure of that. In comparison with the observed current velocity and direction data, it is shown that the modeled results with Mellor's radiation stress formula plus wave roller is able to be consistent with the filed measurement well. This indicates that the modeled wave-induced current is dependent on the vertical structure of radiation stress rather than the vertical integral of that.

  19. [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.

  20. Health risks associated with residential exposure to extremely low frequency electromagnetic radiation

    SciTech Connect

    Lamarine, R.J.; Narad, R.A. )

    1992-10-01

    Extremely low frequency electromagnetic radiation has received considerable attention recently as a possible threat to the health of persons living near high tension electric power lines, distribution substations, and even in close proximity to common household electric appliances. Results of epidemiological and laboratory research are examined to assess risks associated with magnetic fields generated by extremely low frequency electromagnetic sources. Health risks associated with such fields include a wide variety of ills ranging from disruption of normal circadian rhythms to childhood cancers. Risk assessment has been particularly difficult to determine in light of an ostensible lack of a dose-response relationship. Current media sensation fueled in part by an equivocal position adopted by the United States Environmental Protection Agency has contributed to the controversy. Recommendations for prudent avoidance of possible dangers are presented along with policy implications concerning health risks associated with magnetic fields.32 references.

  1. Health risks associated with residential exposure to extremely low frequency electromagnetic radiation.

    PubMed

    Lamarine, R J; Narad, R A

    1992-10-01

    Extremely low frequency electromagnetic radiation has received considerable attention recently as a possible threat to the health of persons living near high tension electric power lines, distribution substations, and even in close proximity to common household electric appliances. Results of epidemiological and laboratory research are examined to assess risks associated with magnetic fields generated by extremely low frequency electromagnetic sources. Health risks associated with such fields include a wide variety of ills ranging from disruption of normal circadian rhythms to childhood cancers. Risk assessment has been particularly difficult to determine in light of an ostensible lack of a dose-response relationship. Current media sensation fueled in part by an equivocal position adopted by the United States Environmental Protection Agency has contributed to the controversy. Recommendations for prudent avoidance of possible dangers are presented along with policy implications concerning health risks associated with magnetic fields.

  2. Ionizing radiation induced leakage current on ultra-thin gate oxides

    SciTech Connect

    Scarpa, A.; Paccagnella, A.; Montera, F.; Ghibaudo, G.; Pananakakis, G.; Fuochi, P.G.

    1997-12-01

    MOS capacitors with a 4.4 nm thick gate oxide have been exposed to {gamma} radiation from a Co{sup 60} source. As a result, the authors have measured a stable leakage current at fields lower than those required for Fowler-Nordheim tunneling. This Radiation Induced Leakage Current (RILC) is similar to the usual Stress Induced Leakage Currents (SILC) observed after electrical stresses of MOS devices. They have verified that these two currents share the same dependence on the oxide field, and the RILC contribution can be normalized to an equivalent injected charge for Constant Current Stresses. They have also considered the dependence of the RILC from the cumulative radiation dose, and from the applied bias during irradiation, suggesting a correlation between RILC and the distribution of trapped holes and neutral levels in the oxide layer.

  3. Contribution for Iron Vapor and Radiation Distribution Affected by Current Frequency of Pulsed Arc

    NASA Astrophysics Data System (ADS)

    Shimokura, Takuya; Mori, Yusuke; Iwao, Toru; Yumoto, Motoshige

    Pulsed GTA welding has been used for improvement of stability, weld speed, and heat input control. However, the temperature and radiation power of the pulsed arc have not been elucidated. Furthermore, arc contamination by metal vapor changes the arc characteristics, e.g. by increasing radiation power. In this case, the metal vapor in pulsed GTA welding changes the distribution of temperature and radiation power as a function of time. This paper presents the relation between metal vapor and radiation power at different pulse frequencies. We calculate the Fe vapor distribution of the pulsed current. Results show that the Fe vapor is transported at fast arc velocity during the peak current period. During the base current period, the Fe vapor concentration is low and distribution is diffuse. The transition of Fe vapor distribution does not follow the pulsed current; the radiation power density distribution differs for high frequencies and low frequencies. In addition, the Fe vapor and radiation distribution are affected by the pulsed arc current frequency.

  4. 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

  5. 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

  6. Ionizing radiation exposure in interventional cardiology: current radiation protection practice of invasive cardiology operators in Lithuania.

    PubMed

    Valuckiene, Zivile; Jurenas, Martynas; Cibulskaite, Inga

    2016-09-01

    Ionizing radiation management is among the most important safety issues in interventional cardiology. Multiple radiation protection measures allow the minimization of x-ray exposure during interventional procedures. Our purpose was to assess the utilization and effectiveness of radiation protection and optimization techniques among interventional cardiologists in Lithuania. Interventional cardiologists of five cardiac centres were interviewed by anonymized questionnaire, addressing personal use of protective garments, shielding, table/detector positioning, frame rate (FR), resolution, field of view adjustment and collimation. Effective patient doses were compared between operators who work with and without x-ray optimization. Thirty one (68.9%) out of 45 Lithuanian interventional cardiologists participated in the survey. Protective aprons were universally used, but not the thyroid collars; 35.5% (n  =  11) operators use protective eyewear and 12.9% (n  =  4) wear radio-protective caps; 83.9% (n  =  26) use overhanging shields, 58.1% (n  =  18)-portable barriers; 12.9% (n  =  4)-abdominal patient's shielding; 35.5% (n  =  11) work at a high table position; 87.1% (n  =  27) keep an image intensifier/receiver close to the patient; 58.1% (n  =  18) reduce the fluoroscopy FR; 6.5% (n  =  2) reduce the fluoro image detail resolution; 83.9% (n  =  26) use a 'store fluoro' option; 41.9% (N  =  13) reduce magnification for catheter transit; 51.6% (n  =  16) limit image magnification; and 35.5% (n  =  11) use image collimation. Median effective patient doses were significantly lower with x-ray optimization techniques in both diagnostic and therapeutic interventions. Many of the ionizing radiation exposure reduction tools and techniques are underused by a considerable proportion of interventional cardiology operators. The application of basic radiation protection tools and

  7. 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.

  8. Radiotherapy for benign disease; assessing the risk of radiation-induced cancer following exposure to intermediate dose radiation

    PubMed Central

    Hatfield, Paul; Prestwich, Robin JD; Shaffer, Richard E; Taylor, Roger E

    2015-01-01

    Most radiotherapy (RT) involves the use of high doses (>50 Gy) to treat malignant disease. However, low to intermediate doses (approximately 3–50 Gy) can provide effective control of a number of benign conditions, ranging from inflammatory/proliferative disorders (e.g. Dupuytren's disease, heterotopic ossification, keloid scarring, pigmented villonodular synovitis) to benign tumours (e.g. glomus tumours or juvenile nasopharyngeal angiofibromas). Current use in UK RT departments is very variable. This review identifies those benign diseases for which RT provides good control of symptoms with, for the most part, minimal side effects. However, exposure to radiation has the potential to cause a radiation-induced cancer (RIC) many years after treatment. The evidence for the magnitude of this risk comes from many disparate sources and is constrained by the small number of long-term studies in relevant clinical cohorts. This review considers the types of evidence available, i.e. theoretical models, phantom studies, epidemiological studies, long-term follow-up of cancer patients and those treated for benign disease, although many of the latter data pertain to treatments that are no longer used. Informative studies are summarized and considered in relation to the potential for development of a RIC in a range of key tissues (skin, brain etc.). Overall, the evidence suggests that the risks of cancer following RT for benign disease for currently advised protocols are small, especially in older patients. However, the balance of risk vs benefit needs to be considered in younger adults and especially if RT is being considered in adolescents or children. PMID:26462717

  9. Overview of Graphical User Interface for ARRBOD (Acute Radiation Risk and BRYNTRN Organ Dose Projection)

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Hu, Shaowen; Nounu, Hatem N.; Cucinotta, Francis A.

    2010-01-01

    Solar particle events (SPEs) pose the risk of acute radiation sickness (ARS) to astronauts, because organ doses from large SPEs may reach critical levels during extra vehicular activities (EVAs) or lightly shielded spacecraft. NASA has developed an organ dose projection model of Baryon transport code (BRYNTRN) with an output data processing module of SUMDOSE, and a probabilistic model of acute radiation risk (ARR). BRYNTRN code operation requires extensive input preparation, and 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, these response models can be connected easily and correctly to BRYNTRN in a user friendly way. The GUI for the Acute Radiation Risk and BRYNTRN Organ Dose (ARRBOD) projection code provides seamless integration of input and output manipulations required for operations of the ARRBOD modules: BRYNTRN, SUMDOSE, and the ARR probabilistic response model. The ARRBOD GUI is intended for mission planners, radiation shield designers, space operations in the mission operations directorate (MOD), and space biophysics researchers. Assessment of astronauts organ doses and ARS from the exposure to historically large SPEs is in support of mission design and operation planning to avoid ARS and stay within the current NASA short-term dose limits. The ARRBOD GUI will serve as a proof-of-concept for future integration of other risk projection models for human space applications. We present an overview of the ARRBOD GUI product, which is a new self-contained product, for the major components of the overall system, subsystem interconnections, and external interfaces.

  10. Overview of Graphical User Interface for ARRBOD (Acute Radiation Risk and BRYNTRN Organ Dose Projection)

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Hee Y.; Hu, Shaowen; Nounu, Hatem; Cucinotta, Francis A.

    Solar particle events (SPEs) pose the risk of acute radiation sickness (ARS) to astronauts be-cause organ doses from large SPEs may reach critical levels during extra vehicular activities (EVAs) or lightly shielded spacecraft. NASA has developed an organ dose projection model of Baryon transport code (BRYNTRN) with an output data processing module of SUMDOSE, and a probabilistic model of acute radiation risk (ARR). BRYNTRN code operation requires extensive input preparation, and 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, these response models can be connected easily and correctly to BRYNTRN in a user-friendly way. The GUI for the Acute Radiation Risk and BRYNTRN Organ Dose (ARRBOD) projection code provides seamless integration of input and output manipulations required for operations of the ARRBOD modules: BRYNTRN, SUMDOSE, and the ARR probabilistic response model. The ARRBOD GUI is intended for mission planners, radiation shield designers, space operations in the mission operations direc-torate (MOD), and space biophysics researchers. Assessment of astronauts' organ doses and ARS from the exposure to historically large SPEs is in support of mission design and opera-tion planning to avoid ARS and stay within the current NASA short-term dose limits. The ARRBOD GUI will serve as a proof-of-concept for future integration of other risk projection models for human space applications. We present an overview of the ARRBOD GUI prod-uct, which is a new self-contained product, for the major components of the overall system, subsystem interconnections, and external interfaces.

  11. 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.

  12. 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

  13. Current advances in synchrotron radiation instrumentation for MX experiments

    DOE PAGES

    Owen, Robin L.; Juanhuix, Jordi; Fuchs, Martin

    2016-04-01

    Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Moreover, it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choicemore » for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. One main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. Furthermore, we discuss the most critical optical components, aspects of endstation design, sample delivery, visualisation and positioning, the sample environment, beam shaping, detectors and data acquisition and processing.« less

  14. Current advances in synchrotron radiation instrumentation for MX experiments

    PubMed Central

    Owen, Robin L.; Juanhuix, Jordi; Fuchs, Martin

    2017-01-01

    Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Furthermore it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choice for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. A main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. The most critical optical components are discussed, as are aspects of endstation design, sample delivery, visualization and positioning, the sample environment, beam shaping, detectors and data acquisition and processing. PMID:27046341

  15. Current advances in synchrotron radiation instrumentation for MX experiments

    SciTech Connect

    Owen, Robin L.; Juanhuix, Jordi; Fuchs, Martin

    2016-04-01

    Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Moreover, it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choice for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. One main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. Furthermore, we discuss the most critical optical components, aspects of endstation design, sample delivery, visualisation and positioning, the sample environment, beam shaping, detectors and data acquisition and processing.

  16. Current advances in synchrotron radiation instrumentation for MX experiments

    SciTech Connect

    Owen, Robin L.; Juanhuix, Jordi; Fuchs, Martin

    2016-07-01

    Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Furthermore it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choice for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. A main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. The most critical optical components are discussed, as are aspects of endstation design, sample delivery, visualisation and positioning, the sample environment, beam shaping, detectors and data acquisition and processing.

  17. Current advances in synchrotron radiation instrumentation for MX experiments.

    PubMed

    Owen, Robin L; Juanhuix, Jordi; Fuchs, Martin

    2016-07-15

    Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Furthermore it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choice for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. A main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. The most critical optical components are discussed, as are aspects of endstation design, sample delivery, visualisation and positioning, the sample environment, beam shaping, detectors and data acquisition and processing. Copyright © 2016. Published by Elsevier Inc.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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

  4. Bibliographical database of radiation biological dosimetry and risk assessment: Part 1, through June 1988

    SciTech Connect

    Straume, T.; Ricker, Y.; Thut, M.

    1988-08-29

    This database was constructed to support research in radiation biological dosimetry and risk assessment. Relevant publications were identified through detailed searches of national and international electronic databases and through our personal knowledge of the subject. Publications were numbered and key worded, and referenced in an electronic data-retrieval system that permits quick access through computerized searches on publication number, authors, key words, title, year, and journal name. Photocopies of all publications contained in the database are maintained in a file that is numerically arranged by citation number. This report of the database is provided as a useful reference and overview. It should be emphasized that the database will grow as new citations are added to it. With that in mind, we arranged this report in order of ascending citation number so that follow-up reports will simply extend this document. The database cite 1212 publications. Publications are from 119 different scientific journals, 27 of these journals are cited at least 5 times. It also contains reference to 42 books and published symposia, and 129 reports. Information relevant to radiation biological dosimetry and risk assessment is widely distributed among the scientific literature, although a few journals clearly dominate. The four journals publishing the largest number of relevant papers are Health Physics, Mutation Research, Radiation Research, and International Journal of Radiation Biology. Publications in Health Physics make up almost 10% of the current database.

  5. 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.

  6. Communicating radiation risk to patients and referring physicians in the emergency department setting.

    PubMed

    Shyu, Jeffrey Y; Sodickson, Aaron D

    2016-01-01

    Heightened awareness about the radiation risks associated with CT imaging has increased patients' wishes to be informed of these risks, and has motivated efforts to reduce radiation dose and eliminate unnecessary imaging. However, many ordering providers, including emergency physicians, are ill prepared to have an informed discussion with patients about the cancer risks related to medical imaging. Radiologists, who generally have greater training in radiation biology and the risks of radiation, often do not have a face-to-face relationship with the patients who are being imaged. A collaborative approach between emergency physicians and radiologists is suggested to help explain these risks to patients who may have concerns about getting medical imaging.

  7. Current scaling of radiated power for 40-mm diameter single wire arrays on Z

    NASA Astrophysics Data System (ADS)

    Nash, T. J.; Cuneo, M. E.; Spielman, R. B.; Chandler, G. A.; Leeper, R. J.; Seaman, J. F.; McGurn, J.; Lazier, S.; Torres, J.; Jobe, D.; Gilliland, T.; Nielsen, D.; Hawn, R.; Bailey, J. E.; Lake, P.; Carlson, A. L.; Seamen, H.; Moore, T.; Smelser, R.; Pyle, J.; Wagoner, T. C.; LePell, P. D.; Deeney, C.; Douglas, M. R.; McDaniel, D.; Struve, K.; Mazarakis, M.; Stygar, W. A.

    2004-11-01

    In order to estimate the radiated power that can be expected from the next-generation Z-pinch driver such as ZR at 28 MA, current-scaling experiments have been conducted on the 20 MA driver Z. We report on the current scaling of single 40 mm diameter tungsten 240 wire arrays with a fixed 110 ns implosion time. The wire diameter is decreased in proportion to the load current. Reducing the charge voltage on the Marx banks reduces the load current. On one shot, firing only three of the four levels of the Z machine further reduced the load current. The radiated energy scaled as the current squared as expected but the radiated power scaled as the current to the 3.52±0.42 power due to increased x-ray pulse width at lower current. As the current is reduced, the rise time of the x-ray pulse increases and at the lowest current value of 10.4 MA, a shoulder appears on the leading edge of the x-ray pulse. In order to determine the nature of the plasma producing the leading edge of the x-ray pulse at low currents further shots were taken with an on-axis aperture to view on-axis precursor plasma. This aperture appeared to perturb the pinch in a favorable manner such that with the aperture in place there was no leading edge to the x-ray pulses at lower currents and the radiated power scaled as the current squared ±0.75. For a full-current shot we will present x-ray images that show precursor plasma emitting on-axis 77 ns before the main x-ray burst.

  8. 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

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  13. Trimming exposure data, putting radiation workers at risk: improving disclosure and consent through a national radiation dose-registry.

    PubMed

    Shrader-Frechette, Kristin

    2007-10-01

    In the United States, regulatory standards allow workers to be exposed to ionizing radiation that can cause 1 additional cancer fatality per 400 workers per year. Because radiation-dose limits cover only single sources (e.g., a nuclear plant) or exposure classes (workplace, medical, or public) and are defined for average occupational exposure, workers typically do not know their precise cumulative, individual, and relative risks from radiation. Nevertheless, this information is necessary for informed consent, because most scientists say radiation effects are cumulative and linear with no risk threshold. To promote public health, informed consent, and better understanding of the effects of low-dose radiation, I argue for a multistage National Radiation-Dose Registry, beginning with cumulative, individual worker doses.

  14. Real-time 3D radiation risk assessment supporting simulation of work in nuclear environments.

    PubMed

    Szőke, I; Louka, M N; Bryntesen, T R; Bratteli, J; Edvardsen, S T; RøEitrheim, K K; Bodor, K

    2014-06-01

    This paper describes the latest developments at the Institute for Energy Technology (IFE) in Norway, in the field of real-time 3D (three-dimensional) radiation risk assessment for the support of work simulation in nuclear environments. 3D computer simulation can greatly facilitate efficient work planning, briefing, and training of workers. It can also support communication within and between work teams, and with advisors, regulators, the media and public, at all the stages of a nuclear installation's lifecycle. Furthermore, it is also a beneficial tool for reviewing current work practices in order to identify possible gaps in procedures, as well as to support the updating of international recommendations, dissemination of experience, and education of the current and future generation of workers.IFE has been involved in research and development into the application of 3D computer simulation and virtual reality (VR) technology to support work in radiological environments in the nuclear sector since the mid 1990s. During this process, two significant software tools have been developed, the VRdose system and the Halden Planner, and a number of publications have been produced to contribute to improving the safety culture in the nuclear industry.This paper describes the radiation risk assessment techniques applied in earlier versions of the VRdose system and the Halden Planner, for visualising radiation fields and calculating dose, and presents new developments towards implementing a flexible and up-to-date dosimetric package in these 3D software tools, based on new developments in the field of radiation protection. The latest versions of these 3D tools are capable of more accurate risk estimation, permit more flexibility via a range of user choices, and are applicable to a wider range of irradiation situations than their predecessors.

  15. Simulation of ion beam induced current in radiation detectors and microelectronic devices.

    SciTech Connect

    Vizkelethy, Gyorgy

    2010-07-01

    Ionizing radiation is known to cause Single Event Effects (SEE) in a variety of electronic devices. The mechanism that leads to these SEEs is current induced by the radiation in these devices. While this phenomenon is detrimental in ICs, this is the basic mechanism behind the operation of semiconductor radiation detectors. To be able to predict SEEs in ICs and detector responses we need to be able to simulate the radiation induced current as the function of time. There are analytical models, which work for very simple detector configurations, but fail for anything more complex. On the other end, TCAD programs can simulate this process in microelectronic devices, but these TCAD codes costs hundreds of thousands of dollars and they require huge computing resources. In addition, in certain cases they fail to predict the correct behavior. A simulation model based on the Gunn theorem was developed and used with the COMSOL Multiphysics framework.

  16. Simulation of ion beam induced current in radiation detectors and microelectronic devices.

    SciTech Connect

    Vizkelethy, Gyorgy

    2009-10-01

    Ionizing radiation is known to cause Single Event Effects (SEE) in a variety of electronic devices. The mechanism that leads to these SEEs is current induced by the radiation in these devices. While this phenomenon is detrimental in ICs, this is the basic mechanism behind the operation of semiconductor radiation detectors. To be able to predict SEEs in ICs and detector responses we need to be able to simulate the radiation induced current as the function of time. There are analytical models, which work for very simple detector configurations, but fail for anything more complex. On the other end, TCAD programs can simulate this process in microelectronic devices, but these TCAD codes costs hundreds of thousands of dollars and they require huge computing resources. In addition, in certain cases they fail to predict the correct behavior. A simulation model based on the Gunn theorem was developed and used with the COMSOL Multiphysics framework.

  17. 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.

  18. 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.

  19. Molecular ecology studies of species radiations: current research gaps, opportunities, and challenges.

    PubMed

    de la Harpe, Marylaure; Paris, Margot; Karger, Dirk N; Rolland, Jonathan; Kessler, Michael; Salamin, Nicolas; Lexer, Christian

    2017-03-18

    Understanding the drivers and limits of species radiations is a crucial goal of evolutionary genetics and molecular ecology, yet research on this topic has been hampered by the notorious difficulty of connecting micro- and macro-evolutionary approaches to studying the drivers of diversification. To chart the current research gaps, opportunities, and challenges of molecular ecology approaches to studying radiations, we examine the literature in the journal Molecular Ecology and re-visit recent high-profile examples of evolutionary genomic research on radiations. We find that available studies of radiations are highly unevenly distributed among taxa, with many ecologically important and species-rich organismal groups remaining severely understudied, including arthropods, plants, and fungi. Most studies employed molecular methods suitable over either short or long evolutionary time scales, such as microsatellites or Restriction site Associated DNA sequencing (RAD-seq) in the former case and conventional amplicon sequencing of organellar DNA in the latter. The potential of molecular ecology studies to address and resolve patterns and processes around the species level in radiating groups of taxa is currently limited primarily by sample size and a dearth of information on radiating nuclear genomes as opposed to organellar ones. Based on our literature survey and personal experience, we suggest possible ways forward in the coming years. We touch on the potential and current limitations of whole genome sequencing (WGS) in studies of radiations. We suggest that WGS and targeted ('capture') resequencing emerge as the methods of choice for scaling up the sampling of populations, species, and genomes, including currently understudied organismal groups and the genes or regulatory elements expected to matter most to species radiations. This article is protected by copyright. All rights reserved.

  20. Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography.

    PubMed

    Einstein, Andrew J; Henzlova, Milena J; Rajagopalan, Sanjay

    2007-07-18

    Computed tomography coronary angiography (CTCA) has become a common diagnostic test, yet there are little data on its associated cancer risk. The recent Biological Effects of Ionizing Radiation (BEIR) VII Phase 2 report provides a framework for estimating lifetime attributable risk (LAR) of cancer incidence associated with radiation exposure from a CTCA study, using the most current data available on health effects of radiation. To determine the LAR of cancer incidence associated with radiation exposure from a 64-slice CTCA study and to evaluate the influence of age, sex, and scan protocol on cancer risk. Organ doses from 64-slice CTCA to standardized phantom (computational model) male and female patients were estimated using Monte Carlo simulation methods, using standard spiral CT protocols. Age- and sex-specific LARs of individual cancers were estimated using the approach of BEIR VII and summed to obtain whole-body LARs. Whole-body and organ LARs of cancer incidence. Organ doses ranged from 42 to 91 mSv for the lungs and 50 to 80 mSv for the female breast. Lifetime cancer risk estimates for standard cardiac scans varied from 1 in 143 for a 20-year-old woman to 1 in 3261 for an 80-year-old man. Use of simulated electrocardiographically controlled tube current modulation (ECTCM) decreased these risk estimates to 1 in 219 and 1 in 5017, respectively. Estimated cancer risks using ECTCM for a 60-year-old woman and a 60-year-old man were 1 in 715 and 1 in 1911, respectively. A combined scan of the heart and aorta had higher LARs, up to 1 in 114 for a 20-year-old woman. The highest organ LARs were for lung cancer and, in younger women, breast cancer. These estimates derived from our simulation models suggest that use of 64-slice CTCA is associated with a nonnegligible LAR of cancer. This risk varies markedly and is considerably greater for women, younger patients, and for combined cardiac and aortic scans.

  1. 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

  2. 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.

  3. ICNIRP Statement on Diagnostic Devices Using Non-ionizing Radiation: Existing Regulations and Potential Health Risks

    PubMed Central

    2017-01-01

    Abstract Use of non-ionizing radiation (NIR) for diagnostic purposes allows non-invasive assessment of the structure and function of the human body and is widely employed in medical care. ICNIRP has published previous statements about the protection of patients during medical magnetic resonance imaging (MRI), but diagnostic methods using other forms of NIR have not been considered. This statement reviews the range of diagnostic NIR devices currently used in clinical settings; documents the relevant regulations and policies covering patients and health care workers; reviews the evidence around potential health risks to patients and health care workers exposed to diagnostic NIR; and identifies situations of high NIR exposure from diagnostic devices in which patients or health care workers might not be adequately protected by current regulations. Diagnostic technologies were classified by the types of NIR that they employ. The aim was to describe the techniques in terms of general device categories which may encompass more specific devices or techniques with similar scientific principles. Relevant legally-binding regulations for protection of patients and workers and organizations responsible for those regulations were summarized. Review of the epidemiological evidence concerning health risks associated with exposure to diagnostic NIR highlighted a lack of data on potential risks to the fetus exposed to MRI during the first trimester, and on long-term health risks in workers exposed to MRI. Most of the relevant epidemiological evidence that is currently available relates to MRI or ultrasound. Exposure limits are needed for exposures from diagnostic technologies using optical radiation within the body. There is a lack of data regarding risk of congenital malformations following exposure to ultrasound in utero in the first trimester and also about the possible health effects of interactions between ultrasound and contrast media. PMID:28121732

  4. A theoretical concept of low level/low LET radiation carcinogenic risk (LLCR) projection

    SciTech Connect

    Filyushkin, I.V.

    1992-06-01

    Carcinogenic risk to humans resulting from low level/low LET radiation exposure (LLLCR) has not been observed directly because epidemiological observations have not yet provided statistically significant data on risk values. However, these values are of great interest for radiation health science and radiation protection practice under both normal conditions and emergency situations. This report presents a theoretical contribution to the validation of dose and dose rate efficiency factors (DDREF) transforming cocinogenic risk coefficients from those revealed in A-bomb survivors to factors appropriate for the projection of the risk resulting from very low levels of low LET radiation.

  5. Radiation-induced radioresistance of mammals and risk assessment

    NASA Astrophysics Data System (ADS)

    Smirnova, O.; Yonezawa, M.

    It is shown experimentally that a preliminary low dose exposure can induce radioresistance in mice in two (early and late) periods after preirradiation. The manifestation of such effects is reduced mortality of pre-exposed specimens after challenge acute irradiation, the reason of the animal death being the hematopoietic subsyndrome of the acute radiation syndrome. Therefore, proceeding from the radiobiological concept of the critical system, the theoretical investigation of the influence of preirradiation on mammalian radiosensitivity is conducted by making use of mathematical models of the vital body system, hematopoiesis. Modeling results make it possible to elucidate the mechanisms of the radioprotection effect of low level priming irradiation on mammals. Specifically, the state of acquired radioresistance in mice is caused by reduced radiosensitivity of lymphopoietic and thrombocytopoietic systems in the early period and by reduced radiosensitivity of granulocytopoietic system in the late period after preirradiation. It is important to emphasize that the evaluations of the duration of the early and late periods of postirradiation radioresistance in mice, carried out on the basis of the modeling and experimental investigations, practically coincide. All this demonstrates the effectiveness of joint modeling and experimental methods in studies and predictions of modification effects of preirradiation on mammalian radiosensitivity. The results obtained show the importance of accounting such effects in radiation risk assessments for cosmonauts and astronauts on long-term missions.

  6. An exploration of Canadian emergency physicians' and residents' knowledge of computed tomography radiation dosing and risk.

    PubMed

    Barbic, David; Barbic, Skye; Dankoff, Jerrald

    2015-03-01

    The objective of this study was to measure the current knowledge of Canadian emergency physicians and emergency medicine residents regarding computed tomography (CT) radiation dosing and its associated risks. Three focus groups were conducted as the qualitative element of this study. Cognitive debriefing was carried out to ensure the validity and reliability of the focus group findings and to aid with survey development. A 26-item electronic survey was developed and pilot tested for distribution to the membership of the Canadian Association of Emergency Physicians. Eighteen emergency medicine physicians and three emergency medicine residents participated in the focus groups. Four major themes emerged: 1) physician knowledge of risks associated with CT, 2) risk management strategies, 3) communication, and 4) knowledge translation. The survey response rate was 49.8% (638 of 1,281). The mean respondent age was 40.9±9.9 years, and 70.7% were male. Of all respondents, 82.5% were actively practicing attending physicians, 56.4% of all respondents practiced in urban academic emergency departments, and the average time practicing was 10.7±9.6 years. Radiography and CT were correctly identified by 92.2% and 95.1% of respondents, respectively, as sources of ionizing radiation, whereas magnetic resonance imaging and ultrasonography were selected by 1.0% and 0.5%, respectively. With respect to the lifetime attributable risk (LAR) of malignancy due to CT, 82.2% of participants correctly identified that abdominal CT increases the risk of cancer by 0.2 to 2%, whereas 51.3% correctly identified that the LAR increases twofold in a 7- year-old boy. When asked to identify populations at risk for potential harm due to ionizing radiation, 92.2% of respondents identified children, 80.3% identified pregnant women, and 71.4% identified women of reproductive age. A minority (37.2%) reported communicating the potential risks of CT to a majority of their patients. Electronic platforms were

  7. Radiation risk and cancer mortality in exposed populations living near the Techa River in Southern Urals

    SciTech Connect

    Kossenko, M.M.; Degteva, M.O.

    1992-06-01

    The appropriateness of applying risk coefficients calculated from short-term exposures at high doses for the assessment of radiation effects at low doses is currently much debated. The problem can be resolved on the basis of the data obtained from a long-term follow-up of the population exposed in the early 1950s when discharges of radioactive wastes from a radiochemical plant into the Techa River (southern Urals) occurred. This paper discusses the results of an analysis of cancer mortality during the period 1950-82. 10 refs., 5 figs., 8 tabs.

  8. Radiation-induced health effects on atmospheric flight crew members: clues for a radiation-related risk analysis.

    PubMed

    De Angelis, G; Caldora, M; Santaquilani, M; Scipione, R; Verdecchia, A

    2002-01-01

    There are few human data on low-dose-rate-radiation exposure and the consequent acute and late effects. This fact makes it difficult to assess health risks due to radiation in the space environment, especially for long-term missions. Epidemiological data on civilian flight personnel cohorts can provide information on effects due to the low-dose and low-dose rate mixed high- and low-LET radiation environment in the earth's atmosphere. The physical characteristics of the radiation environment of the atmosphere make the results of the studies of commercial flight personnel relevant to the studies of activities in space. The cooperative international effort now in progress to investigate dose reconstructions will contribute to our understanding of radiation risks for space exploration. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  9. Parametrization of the radiation induced leakage current increase of NMOS transistors

    NASA Astrophysics Data System (ADS)

    Backhaus, M.

    2017-01-01

    The increase of the leakage current of NMOS transistors during exposure to ionizing radiation is known and well studied. Radiation hardness by design techniques have been developed to mitigate this effect and have been successfully used. More recent developments in smaller feature size technologies do not make use of these techniques due to their drawbacks in terms of logic density and requirement of dedicated libraries. During operation the resulting increase of the supply current is a serious challenge and needs to be considered during the system design. A simple parametrization of the leakage current of NMOS transistors as a function of total ionizing dose is presented. The parametrization uses a transistor transfer characteristics of the parasitic transistor along the shallow trench isolation to describe the leakage current of the nominal transistor. Together with a parametrization of the number of positive charges trapped in the silicon dioxide and number of activated interface traps in the silicon to silicon dioxide interface the leakage current results as a function of the exposure time to ionizing radiation. This function is fitted to data of the leakage current of single transistors as well as to data of the supply current of full ASICs.

  10. Smokers May Be Prone to Risks from Breast Cancer Radiation Therapy

    MedlinePlus

    ... html Smokers May Be Prone to Risks From Breast Cancer Radiation Therapy Long-term chances of heart attack, ... 29, 2017 WEDNESDAY, March 29, 2017 (HealthDay News) -- Breast cancer patients who smoke have an increased risk for ...

  11. Current directions in screening-level ecological risk assessments

    SciTech Connect

    Carlsen, T M; Efroymson, R A

    2000-12-11

    Ecological risk assessment (ERA) is a tool used by many regulatory agencies to evaluate the impact to ecological receptors from changes in environmental conditions. Widespread use of ERAs began with the United States Environmental Protection Agency's Superfund program to assess the ecological impact from hazardous chemicals released to the environment. Many state hazardous chemical regulatory agencies have adopted the use of ERAs, and several state regulatory agencies are evaluating the use of ERAs to assess ecological impacts from releases of petroleum and gas-related products. Typical ERAs are toxicologically-based, use conservative assumptions with respect to ecological receptor exposure duration and frequency, often require complex modeling of transport and exposure and are very labor intensive. In an effort to streamline the ERA process, efforts are currently underway to develop default soil screening levels, to identify ecological screening criteria for excluding sites from formal risk assessment, and to create risk-based corrective action worksheets. This should help reduce the time spent on ERAs, at least for some sites. Work is also underway to incorporate bioavailability and spatial considerations into ERAs. By evaluating the spatial nature of contaminant releases with respect to the spatial context of the ecosystem under consideration, more realistic ERAs with respect to the actual impact to ecological receptors at the population, community or ecosystem scale should be possible. In addition, by considering the spatial context, it should be possible to develop mitigation and monitoring efforts to more appropriately address such sites within the context of an ecological framework.

  12. 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.

  13. CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?

    EPA Science Inventory

    Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?

    Abstract
    High doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situatio...

  14. CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?

    EPA Science Inventory

    Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?

    Abstract
    High doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situatio...

  15. Some current advances in biophysical applications of ionizing radiation for health preservation

    NASA Astrophysics Data System (ADS)

    Watt, D. E.

    1987-03-01

    Radiation Physics is a subject of major importance in application to health preservation through investigative, diagnostic, analytical and therapeutic procedures for clinical purposes. Its benefits are enormous and well-established. However there are also hazards and so it is important for health preservation purposes to establish quantitatively the degree of risk undergone by persons exposed to radiation in the natural environment, in their occupations and in medical treatment. In this paper a brief indication is given of the extensive utilisation of the unique properties of radiation in biomedical application. This is followed by fuller discussion on new developments in our understanding of radiation damage mechanisms in radiotherapy and radiological protection. An example is given in biomedical research into the role of trace elements in gallstone formation using neutron activation anaysis, proton induced X-ray emission and X-ray fluorescence analysis as complementary techniques for maximising sensitivity in multielemental analysis by induced radiation. Procedures are described for measuring radiation effect, at bone/ tissue and lung/air interfaces, due to the uptake of radioactive material from the natural environment. Finally a topical subject in nuclear medicine viz. the possible advantages and hazards of Auger electron cascades resulting from inner shell vacancies in electron capture nuclides, is examined in the light of new evidence.

  16. Nausea and vomiting induced by gastrointestinal radiation therapy: current status and future directions.

    PubMed

    Dennis, Kristopher; Poon, Michael; Chow, Edward

    2015-06-01

    Radiation therapy-induced nausea and vomiting (RINV) are common and troublesome symptoms among patients receiving radiation therapy for gastrointestinal cancers. Their impact on function, quality of life and, ultimately, cancer control warrant a review of their incidence, underlying mechanisms, treatments and research themes. Research in RINV is underrepresented relative to that in chemotherapy-induced nausea and vomiting. The incidence of RINV among patients receiving modern day radiation therapy is questioned and supportive care practice patterns vary among radiation oncologists. Antiemetic guideline recommendations for prophylactic and rescue therapy are based solely on the anatomic region being irradiated and not other patient-related, radiation therapy-related, or organ-specific dosimetric factors that likely modulate the risk of RINV. Dosimetric predictors are likely the most attainable biomarker moving forward, but only early steps have been taken. The small bowel and stomach will be the best first candidates for study among patients with gastrointestinal cancers. Studies of the mechanisms underlying RINV are conspicuously lacking. A new generation of observational studies and therapeutic clinical trials is needed, and more attention must be given to the relative impact of nausea and vomiting on the function and quality of life among specific homogeneous patient populations. Optimal supportive care strategies for RINV following radiation therapy for gastrointestinal cancers are lacking, and will not be known until future research answers the many open questions regarding the mechanisms underlying RINV, the true incidence and impact of these symptoms among patients and the best way to predict and mitigate them.

  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. Risk management of seasonal influenza during pregnancy: current perspectives

    PubMed Central

    Yudin, Mark H

    2014-01-01

    Influenza poses unique risks to pregnant women, who are particularly susceptible to morbidity and mortality. Historically, pregnant women have been overrepresented among patients with severe illness and complications from influenza, and have been more likely to require hospitalization and intensive care unit admission. An increased risk of adverse outcomes is also present for fetuses/neonates born to women affected by influenza during pregnancy. These risks to mothers and babies have been observed during both nonpandemic and pandemic influenza seasons. During the H1N1 influenza pandemic of 2009–2010, pregnant women were more likely to be hospitalized or admitted to intensive care units, and were at higher risk of death compared to nonpregnant adults. Vaccination remains the most effective intervention to prevent severe illness, and antiviral medications are an important adjunct to ameliorate disease when it occurs. Unfortunately, despite national guidelines recommending universal vaccination for women who are pregnant during influenza season, actual vaccination rates do not achieve desired targets among pregnant women. Pregnant women are also sometimes reluctant to use antiviral medications during pregnancy. Some of the barriers to use of vaccines and medications during pregnancy are a lack of knowledge of recommendations and of safety data. By improving knowledge and understanding of influenza and vaccination recommendations, vaccine acceptance rates among pregnant women can be improved. Currently, the appropriate use of vaccination and antiviral medications is the best line of defense against influenza and its sequelae among pregnant women, and strategies to increase acceptance are crucial. This article will review the importance of influenza in pregnancy, and discuss vaccination and antiviral medications for pregnant women. PMID:25114593

  19. Communicating Potential Radiation-Induced Cancer Risks From Medical Imaging Directly to Patients.

    PubMed

    Lam, Diana L; Larson, David B; Eisenberg, Jonathan D; Forman, Howard P; Lee, Christoph I

    2015-11-01

    Over the past decade, efforts have increasingly been made to decrease radiation dose from medical imaging. However, there remain varied opinions about whether, for whom, by whom, and how these potential risks should be discussed with patients. We aimed to provide a review of the literature regarding awareness and communication of potential radiation-induced cancer risks from medical imaging procedures in hopes of providing guidance for communicating these potential risks with patients. We performed a systematic literature review on the topics of radiation dose and radiation-induced cancer risk awareness, informed consent regarding radiation dose, and communication of radiation-induced cancer risks with patients undergoing medical imaging. We included original research articles from North America and Europe published between 1995 and 2014. From more than 1200 identified references, a total of 22 original research articles met our inclusion criteria. Overall, we found that there is insufficient knowledge regarding radiation-induced cancer risks and the magnitude of radiation dose associated with CT examinations among patients and physicians. Moreover, there is minimal sharing of information before nonacute imaging studies between patients and physicians about potential long-term radiation risks. Despite growing concerns regarding medical radiation exposure, there is still limited awareness of radiation-induced cancer risks among patients and physicians. There is also no consensus regarding who should provide patients with relevant information, as well as in what specific situations and exactly what information should be communicated. Radiologists should prioritize development of consensus statements and novel educational initiatives with regard to radiation-induced cancer risk awareness and communication.

  20. Mobile phone radiation and the risk of cancer; a review.

    PubMed

    Abdus-salam, A; Elumelu, T; Adenipekun, A

    2008-06-01

    With the licensing of mobile phone operators about 7 years ago, Nigeria joined many countries where worries about the health risks (including carcinogenesis) of mobile phones have become common. Opinions have also been expressed by many, some of which were inaccurate in the light of scientific evidence. This article reviewed the current scientific evidence of the role of mobile phones as possible cancer risk. The preponderance of published research works over several decades including some with over ten years of follow up have not demonstrated any significant increase in cancer among mobile phone users. However, the need for caution is emphasized as it may take up to four decades for carcinogenesis to become fully apparent.

  1. 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

  2. Late radiation responses in man: current evaluation from results from Hiroshima and Nagasaki.

    PubMed

    Schull, W J

    1983-01-01

    Among the late effects of exposure to the atomic bombings of Hiroshima and Nagasaki, none looms larger than radiation related malignancies. Indeed, the late effects of A-bomb radiation on mortality appear to be limited to an increase in malignant tumors. At present, it can be shown that cancers of the breast, colon, esophagus, lungs, stomach, thyroid, and urinary tract as well as leukemia and multiple myeloma increase in frequency with an increase in exposure. No significant relationship to radiation can as yet be established for malignant lymphoma, nor cancers of the rectum, pancreas or uterus. Radiation induced malignancies other than leukemia seem to develop proportionally to the natural cancer rate for the attained age. For specific age-at-death intervals, both relative and absolute risks tend to be higher for those of younger age at the time of bombing. Other late effects include radiation-related lenticular opacities, disturbances of growth among those survivors still growing at the time of exposure, and mental retardation and small head sizes among the in utero exposed. Chromosomal abnormalities too are more frequently encountered in the peripheral leukocytes of survivors, and this increase is functionally related to their exposure. Some uncertainty continues to surround both the quantity and quality of the radiation released by these two nuclear devices, particularly the Hiroshima bomb. A recent reassessment suggests that the gamma radiation estimates which have been used in the past may be too low at some distances and the neutron radiation estimates too high at all distances; moreover, the energies of the neutrons released now appear "softer" than previously conjectured. These uncertainties are not sufficiently large, however, to compromise the reality of the increased frequency of malignancy, but make estimates of the dose response, particularly in terms of gamma and neutron exposures, tentative.

  3. Late radiation responses in man: Current evaluation from results from Hiroshima and Nagasaki

    NASA Astrophysics Data System (ADS)

    Schull, William J.

    Among the late effects of exposure to the atomic bombings of Hiroshima and Nagasaki, none looms larger than radiation related malignancies. Indeed, the late effects of A-bomb radiation on mortality appear to be limited to an increase in malignant tumors. At present, it can be shown that cancers of the breast, colon, esophagus, lungs, stomach, thyroid, and urinary tract as well as leukemia and multiple myeloma increase in frequency with an increase in exposure. No significant relationship to radiation can as yet be established for malignant lymphoma, nor cancers of the rectum, pancreas or uterus. Radiation induced malignancies other than leukemia seem to develop proportionally to the natural cancer rate for the attained age. For specific age-at-death intervals, both relative and absolute risks tend to be higher for those of younger age at the time of bombing. Other late effects include radiation-related lenticular opacities, disturbances of growth among those survivors still growing at the time of exposure, and mental retardation and small head sizes among the in utero exposed. Chromosomal abnormalities too are more frequently encountered in the peripheral leucocytes of survivors, and this increase is functionally related to their exposure. Some uncertainty continues to surround both the quantity and quality of the radiation released by these two nuclear devices, particularly the Hiroshima bomb. A recent reassessment suggests that the gamma radiation estimates which have been used in the past may be too low at some distances and the neutron radiation estimates too high at all distances; moreover, the energies of the neutrons released now appear ``softer'' than previously conjectured. These uncertainties not sufficiently large, however, to compromise the reality of the increased frequency of malignancy, but make estimates of the dose response, particularly in terms of gamma and neutron exposures, tentative.

  4. The effect of dose heterogeneity on radiation risk in medical imaging.

    PubMed

    Samei, Ehsan; Li, Xiang; Chen, Baiyu; Reiman, Robert

    2013-06-01

    The current estimations of risk associated with medical imaging procedures rely on assessing the organ dose via direct measurements or simulation. The dose to each organ is assumed to be homogeneous. To take into account the differences in radiation sensitivities, the mean organ doses are weighted by a corresponding tissue-weighting coefficients provided by ICRP to calculate the effective dose, which has been used as a surrogate of radiation risk. However, those coefficients were derived under the assumption of a homogeneous dose distribution within each organ. That assumption is significantly violated in most medical-imaging procedures. In helical chest CT, for example, superficial organs (e.g. breasts) demonstrate a heterogeneous dose distribution, whereas organs on the peripheries of the irradiation field (e.g. liver) might possess a discontinuous dose profile. Projection radiography and mammography involve an even higher level 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. In this paper, the magnitude of the dose heterogeneity in both CT and projection X-ray imaging was reported, using Monte Carlo methods. The lung dose demonstrated factors of 1.7 and 2.2 difference between the mean and maximum dose for chest CT and radiography, respectively. The corresponding values for the liver were 1.9 and 3.5. For mammography and breast tomosynthesis, the difference between mean glandular dose and maximum glandular dose was 3.1. Risk models based on the mean dose were found to provide a reasonable reflection of cancer risk. However, for leukaemia, they were found to significantly under-represent the risk when the organ dose distribution is heterogeneous. A systematic study is needed to develop a risk model for heterogeneous dose distributions.

  5. Current and future flood risk to railway infrastructure in Europe

    NASA Astrophysics Data System (ADS)

    Bubeck, Philip; Kellermann, Patric; Alfieri, Lorenzo; Feyen, Luc; Dillenardt, Lisa; Thieken, Annegret H.

    2017-04-01

    CORINE, due to their line shapes. To assess current and future damage and risk to railway infrastructure in Europe, we apply the damage model RAIL -' RAilway Infrastructure Loss' that was specifically developed for railway infrastructure using empirical damage data. To adequately and comprehensively capture the line-shaped features of railway infrastructure, the assessment makes use of the open-access data set of openrailway.org. Current and future flood hazard in Europe is obtained with the LISFLOOD-based pan-European flood hazard mapping procedure combined with ensemble projections of extreme streamflow for the current century based on EURO-CORDEX RCP 8.5 climate scenarios. The presentation shows first results of the combination of the hazard data and the model RAIL for Europe.

  6. TU-C-18A-01: Models of Risk From Low-Dose Radiation Exposures: What Does the Evidence Say?

    SciTech Connect

    Bushberg, J; Boreham, D; Ulsh, B

    2014-06-15

    At dose levels of (approximately) 500 mSv or more, increased cancer incidence and mortality have been clearly demonstrated. However, at the low doses of radiation used in medical imaging, the relationship between dose and cancer risk is not well established. As such, assumptions about the shape of the dose-response curve are made. These assumptions, or risk models, are used to estimate potential long term effects. Common models include 1) the linear non-threshold (LNT) model, 2) threshold models with either a linear or curvilinear dose response above the threshold, and 3) a hormetic model, where the risk is initially decreased below background levels before increasing. The choice of model used when making radiation risk or protection calculations and decisions can have significant implications on public policy and health care decisions. However, the ongoing debate about which risk model best describes the dose-response relationship at low doses of radiation makes informed decision making difficult. This symposium will review the two fundamental approaches to determining the risk associated with low doses of ionizing radiation, namely radiation epidemiology and radiation biology. The strengths and limitations of each approach will be reviewed, the results of recent studies presented, and the appropriateness of different risk models for various real world scenarios discussed. Examples of well-designed and poorly-designed studies will be provided to assist medical physicists in 1) critically evaluating publications in the field and 2) communicating accurate information to medical professionals, patients, and members of the general public. Equipped with the best information that radiation epidemiology and radiation biology can currently provide, and an understanding of the limitations of such information, individuals and organizations will be able to make more informed decisions regarding questions such as 1) how much shielding to install at medical facilities, 2) at

  7. 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.

  8. Review of the Current State of Knowledge on the Effects of Radiation on Concrete

    SciTech Connect

    Rosseel, Thomas M.; Maruyama, Ippei; Le Pape, Yann; Kontani, Osamu; Giorla, Alain B.; Remec, Igor; Wall, James J.; Sircar, Madhumita; Andrade, Carmen; Ordonez, Manuel

    2016-07-01

    A review of the current state of knowledge on the effects of radiation on concrete in nuclear applications is presented. Emphasis is placed on the effects of radiation damage as reflected by changes in engineering properties of concrete in the evaluation of the long-term operation (LTO) and for Plant Life or Aging Management of nuclear power plants (NPPs) in Japan, Spain, and the United States. National issues and concerns are described for Japan and the US followed by a discussion of the fundamental understanding of the effects radiation on concrete. Specifically, the effects of temperature, moisture content, and irradiation on ordinary Portland cement paste and the role of temperature and neutron energy spectra on radiation induced volumetric expansion (RIVE) of aggregate-forming minerals are described. This is followed by a discussion of the bounding conditions for extended operation, the significance of accelerated irradiation conditions, the role of temperature, creep, and how these issues are being incorporated into numerical and meso-scale models. From these insights on radiation damage, analyses of these effects on concrete structures are reviewed and the current status of work in Japan and the US are described. Also discussed is the recent formation of a new international scientific and technical organization, the International Committee on Irradiated Concrete (ICIC), to provide a forum for timely information exchanges among organizations pursuing the identification, quantification, and modeling of the effects of radiation on concrete in commercial nuclear applications. Lastly, the paper concludes with a discussion of research gaps including: 1) interpreting test-reactor data, 2) evaluating service-irradiated concrete for aging management and to inform radiation damage models with the Zorita NPP (Spain) serving as the first comprehensive test case, 3) irradiated-assisted alkali-silica reactions, and 4) RIVE under constrained conditions.

  9. Review of the Current State of Knowledge on the Effects of Radiation on Concrete

    DOE PAGES

    Rosseel, Thomas M.; Maruyama, Ippei; Le Pape, Yann; ...

    2016-07-01

    A review of the current state of knowledge on the effects of radiation on concrete in nuclear applications is presented. Emphasis is placed on the effects of radiation damage as reflected by changes in engineering properties of concrete in the evaluation of the long-term operation (LTO) and for Plant Life or Aging Management of nuclear power plants (NPPs) in Japan, Spain, and the United States. National issues and concerns are described for Japan and the US followed by a discussion of the fundamental understanding of the effects radiation on concrete. Specifically, the effects of temperature, moisture content, and irradiation onmore » ordinary Portland cement paste and the role of temperature and neutron energy spectra on radiation induced volumetric expansion (RIVE) of aggregate-forming minerals are described. This is followed by a discussion of the bounding conditions for extended operation, the significance of accelerated irradiation conditions, the role of temperature, creep, and how these issues are being incorporated into numerical and meso-scale models. From these insights on radiation damage, analyses of these effects on concrete structures are reviewed and the current status of work in Japan and the US are described. Also discussed is the recent formation of a new international scientific and technical organization, the International Committee on Irradiated Concrete (ICIC), to provide a forum for timely information exchanges among organizations pursuing the identification, quantification, and modeling of the effects of radiation on concrete in commercial nuclear applications. Lastly, the paper concludes with a discussion of research gaps including: 1) interpreting test-reactor data, 2) evaluating service-irradiated concrete for aging management and to inform radiation damage models with the Zorita NPP (Spain) serving as the first comprehensive test case, 3) irradiated-assisted alkali-silica reactions, and 4) RIVE under constrained conditions.« less

  10. Review of the Current State of Knowledge on the Effects of Radiation on Concrete

    SciTech Connect

    Rosseel, Thomas M.; Maruyama, Ippei; Le Pape, Yann; Kontani, Osamu; Giorla, Alain B.; Remec, Igor; Wall, James J.; Sircar, Madhumita; Andrade, Carmen; Ordonez, Manuel

    2016-07-01

    A review of the current state of knowledge on the effects of radiation on concrete in nuclear applications is presented. Emphasis is placed on the effects of radiation damage as reflected by changes in engineering properties of concrete in the evaluation of the long-term operation (LTO) and for Plant Life or Aging Management of nuclear power plants (NPPs) in Japan, Spain, and the United States. National issues and concerns are described for Japan and the US followed by a discussion of the fundamental understanding of the effects radiation on concrete. Specifically, the effects of temperature, moisture content, and irradiation on ordinary Portland cement paste and the role of temperature and neutron energy spectra on radiation induced volumetric expansion (RIVE) of aggregate-forming minerals are described. This is followed by a discussion of the bounding conditions for extended operation, the significance of accelerated irradiation conditions, the role of temperature, creep, and how these issues are being incorporated into numerical and meso-scale models. From these insights on radiation damage, analyses of these effects on concrete structures are reviewed and the current status of work in Japan and the US are described. Also discussed is the recent formation of a new international scientific and technical organization, the International Committee on Irradiated Concrete (ICIC), to provide a forum for timely information exchanges among organizations pursuing the identification, quantification, and modeling of the effects of radiation on concrete in commercial nuclear applications. Lastly, the paper concludes with a discussion of research gaps including: 1) interpreting test-reactor data, 2) evaluating service-irradiated concrete for aging management and to inform radiation damage models with the Zorita NPP (Spain) serving as the first comprehensive test case, 3) irradiated-assisted alkali-silica reactions, and 4) RIVE under constrained conditions.

  11. 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

  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. Current Control and Future Risk in Asthma Management

    PubMed Central

    Sims, Erika J; Haughney, John; Ryan, Dermot; Thomas, Mike

    2011-01-01

    Despite international and national guidelines, poor asthma control remains an issue. Asthma exacerbations are costly to both the individual, and the healthcare provider. Improvements in our understanding of the therapeutic benefit of asthma therapies suggest that, in general, while long-acting bronchodilator therapy improves asthma symptoms, the anti-inflammatory activity of inhaled corticosteroids reduces acute asthma exacerbations. Studies have explored factors which could be predictive of exacerbations. A history of previous exacerbations, poor asthma control, poor inhaler technique, a history of lower respiratory tract infections, poor adherence to medication, the presence of allergic rhinitis, gastro-oesophageal reflux disease, psychological dysfunction, smoking and obesity have all been implicated as having a predictive role in the future risk of asthma exacerbation. Here we review the current literature and discuss this in the context of primary care management of asthma. PMID:21966601

  14. Effect of reabsorbed recombination radiation on the saturation current of direct gap p-n junctions

    NASA Technical Reports Server (NTRS)

    Von Roos, O.; Mavromatis, H.

    1984-01-01

    The application of the radiative transfer theory for semiconductors to p-n homojunctions subject to low level injection conditions is discussed. By virtue of the interaction of the radiation field with free carriers across the depletion layer, the saturation current density in Shockley's expression for the diode current is reduced at high doping levels. The reduction, due to self-induced photon generation, is noticeable for n-type material owing to the small electron effective mass in direct band-gap III-V compounds. The effect is insignificant in p-type material. At an equilibrium electron concentration of 2 x 10 to the 18th/cu cm in GaAs, a reduction of the saturation current density by 15 percent is predicted. It is concluded that realistic GaAs p-n junctions possess a finite thickness.

  15. Current issues in dietary acrylamide: formation, mitigation and risk assessment.

    PubMed

    Pedreschi, Franco; Mariotti, María Salomé; Granby, Kit

    2014-01-15

    Acrylamide (AA) is known as a neurotoxin in humans and it is classified as a probable human carcinogen by the International Agency of Research on Cancer. AA is produced as by-product of the Maillard reaction in starchy foods processed at high temperatures (>120 °C). This review includes the investigation of AA precursors, mechanisms of AA formation and AA mitigation technologies in potato, cereal and coffee products. Additionally, most relevant issues of AA risk assessment are discussed. New technologies tested from laboratory to industrial scale face, as a major challenge, the reduction of AA content of browned food, while still maintaining its attractive organoleptic properties. Reducing sugars such as glucose and fructose are the major contributors to AA in potato-based products. On the other hand, the limiting substrate of AA formation in cereals and coffee is the free amino acid asparagine. For some products the addition of glycine or asparaginase reduces AA formation during baking. Since, for potatoes, the limiting substrate is reducing sugars, increases in sugar content in potatoes during storage then introduce some difficulties and potentially quite large variations in the AA content of the final product. Sugars in potatoes may be reduced by blanching. Levels of AA in different foods show large variations and no general upper limit is easily applicable, since some formation will always occur. Current policy is that practical measures should be taken voluntarily to reduce AA formation in vulnerable foods since AA is considered a health risk at the concentrations found in foods.

  16. A unifying concept for carcinogenic risk assessments: comparison with radiation-induced leukemia in mice and men.

    PubMed

    Jones, T D

    1984-10-01

    This paper presents a new, general mathematical dose-response model which can use human, animal and cell culture data to predict the incidence of leukemia as a result of exposure to ionizing radiations. The model is based on simple considerations of fundamental biological processes of carcinogenic initiation, carcinogenic promotion and competing risk due to other toxic or disease reactions. The model can be used to predict the risk of leukemia for either human or animal populations which have been (or will be) treated with any radiation dose-time treatment protocol of interest. The model is both an extension and an outgrowth of earlier work done for the Oak Ridge dosimetry program in support activities for the Atomic Bomb Casualty Commission (formerly) and the Radiation Effects Research Foundation (currently).

  17. Cardiovascular risk in operators under radiofrequency electromagnetic radiation.

    PubMed

    Vangelova, Katia; Deyanov, Christo; Israel, Mishel

    2006-03-01

    The aim of the study was to assess the long-term effects of radiofrequency electromagnetic radiation (EMR) on the cardiovascular system. Two groups of exposed operators (49 broadcasting (BC) station and 61 TV station operators) and a control group of 110 radiorelay station operators, matched by sex and age, with similar job characteristics except for the radiofrequency EMR were studied. The EMR exposure was assessed and the time-weighted average (TWA) was calculated. The cardiovascular risk factors arterial pressure, lipid profile, body mass index, waist/hip ratio, smoking, and family history of cardiovascular disease were followed. The systolic and diastolic blood pressure (SBP and DBP), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were significantly higher in the two exposed groups. It was found that the radiofrequency EMR exposure was associated with greater chance of becoming hypertensive and dyslipidemic. The stepwise multiple regression equations showed that the SBP and TWA predicted the high TC and high LDL-C, while the TC, age and abdominal obesity were predictors for high SBP and DBP. In conclusion, our data show that the radiofrequency EMR contributes to adverse effects on the cardiovascular system.

  18. WE-C-217A-03: Biology versus Epidemiology: The Need for an Integrated Model of Radiation Risk.

    PubMed

    Vetter, D

    2012-06-01

    radiation. 1. List the current biological mechanisms that are affected by low doses of ionizing radiation. 2. Describe the dilemma of risk extrapolation based on current knowledge of biological effects of radiation. 3. Discuss the limitations of extrapolating lifetime attributable risk estimates to cancer mortality for low-dose medical procedures. © 2012 American Association of Physicists in Medicine.

  19. Current Status of Chemical Public Health Risks and Testing ...

    EPA Pesticide Factsheets

    The cardiovascular system, at all its various developmental and life stages, represents a critical target organ system that can be adversely affected by a variety of chemicals and routes of exposure. A World Health Organization report estimated the impact of environmental chemical exposures on health to be 16% (range: 7—23%) of the total global burden of cardiovascular disease, corresponding to ~2.5 million deaths per year. Currently, the overall impact of environmental chemical exposures on all causes of cardiovascular disease and the number one cause of morbidity and mortality in the United States is unknown. Evidence from epidemiology, clinical, and toxicological studies will be presented documenting adverse cardiovascular effects associated with environmental exposure to chemicals. The presentation will cover US EPA’s ability to regulate and test chemicals as well as current challenges faced by the Agency to assess chemical cardiovascular risk and public health safety. (This abstract does not necessarily reflect US EPA Policy) Will be presented at the Workshop titled

  20. 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. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Risk Analysis Training within the Army: Current Status, Future Trends,

    DTIC Science & Technology

    risk analysis . Since risk analysis training in the Army is...become involved in risk analysis training. He reviews all risk analysis -related training done in any course at the Center. Also provided is information...expected to use the training. Then the future trend in risk analysis training is presented. New course, course changes and hardware/software changes that will make risk analysis more palatable are

  3. 2013 Space Radiation Standing Review Panel Status Review for: The Risk of Acute and Late Central Nervous System Effects from Radiation Exposure, The Risk of Acute Radiation Syndromes Due to Solar Particle Events (SPEs), The Risk Of Degenerative Tissue Or Other Health Effects From Radiation Exposure, and The Risk of Radiation Carcinogenesis

    NASA Technical Reports Server (NTRS)

    2014-01-01

    The Space Radiation Standing Review Panel (from here on referred to as the SRP) was impressed with the strong research program presented by the scientists and staff associated with NASA's Space Radiation Program Element and National Space Biomedical Research Institute (NSBRI). The presentations given on-site and the reports of ongoing research that were provided in advance indicated the potential Risk of Acute and Late Central Nervous System Effects from Radiation Exposure (CNS) and were extensively discussed by the SRP. This new data leads the SRP to recommend that a higher priority should be placed on research designed to identify and understand these risks at the mechanistic level. To support this effort the SRP feels that a shift of emphasis from Acute Radiation Syndromes (ARS) and carcinogenesis to CNS-related endpoints is justified at this point. However, these research efforts need to focus on mechanisms, should follow pace with advances in the field of CNS in general and should consider the specific comments and suggestions made by the SRP as outlined below. The SRP further recommends that the Space Radiation Program Element continue with its efforts to fill the vacant positions (Element Scientist, CNS Risk Discipline Lead) as soon as possible. The SRP also strongly recommends that NASA should continue the NASA Space Radiation Summer School. In addition to these broad recommendations, there are specific comments/recommendations noted for each risk, described in detail below.

  4. Image-guided intraoperative radiation therapy: current developments and future perspectives.

    PubMed

    Pascau, Javier

    2014-09-01

    Intraoperative electron beam radiation therapy (IOERT) procedures involve the delivery of radiation to a target area during surgery by means of a specific applicator. This treatment is currently planned by means of specific systems that incorporate tools for both surgical simulation and radiation dose distribution estimation. Although the planning step improves treatment quality and facilitates follow-up, the actual position of the patient, the applicator and other tools during the surgical procedure is unknown. Image-guided navigation technologies could be introduced in IOERT treatments, but an innovative solution that overcomes the limitations of these systems in complex surgical scenarios is needed. A recent publication describes a multi-camera optical tracking system integrated in IOERT workflow. This technology has shown appropriate accuracy in phantom experiments, and could also be of interest in other surgical interventions, where the restrictions solved by this system are also present.

  5. Radiation Dose to Patients from Radiopharmaceuticals: a Compendium of Current Information Related to Frequently Used Substances.

    PubMed

    Mattsson, S; Johansson, L; Leide Svegborn, S; Liniecki, J; Noßke, D; Riklund, K Å; Stabin, M; Taylor, D; Bolch, W; Carlsson, S; Eckerman, K; Giussani, A; Söderberg, L; Valind, S

    2015-07-01

    This report provides a compendium of current information relating to radiation dose to patients, including biokinetic models, biokinetic data, dose coefficients for organ and tissue absorbed doses, and effective dose for major radiopharmaceuticals based on the radiation protection guidance given in Publication 60(ICRP, 1991). These data were mainly compiled from Publications 53, 80, and 106(ICRP, 1987, 1998, 2008), and related amendments and corrections. This report also includes new information for 82Rb-chloride, iodide (123I, 124I, 125I, and 131I) and 123I labeled 2ß-carbomethoxy 3ß-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (FPCIT).The coefficients tabulated in this publication will be superseded in due course by values calculated using new International Commission on Radiation Units and Measurements/International Commission on Radiological Protection adult and paediatric reference phantoms and Publication 103 methodology (ICRP,2007). The data presented in this report are intended for diagnostic nuclear medicine and not for therapeutic applications.

  6. Radiation induced currents in MRI RF coils: application to linac/MRI integration

    PubMed Central

    Burke, B; Fallone, B G; Rathee, S

    2010-01-01

    The integration of medical linear accelerators (linac) with magnetic resonance imaging (MRI) systems is advancing the current state of image-guided radiotherapy. The MRI in these integrated units will provide real-time, accurate tumor locations for radiotherapy treatment, thus decreasing geometric margins around tumors and reducing normal tissue damage. In the real-time operation of these integrated systems, the radiofrequency (RF) coils of MRI will be irradiated with radiation pulses from the linac. The effect of pulsed radiation on MRI radio frequency (RF) coils is not known and must be studied. The instantaneous radiation induced current (RIC) in two different MRI RF coils were measured and presented. The frequency spectra of the induced currents were calculated. Some basic characterization of the RIC was also done: isolation of the RF coil component responsible for RIC, dependence of RIC on dose rate, and effect of wax buildup placed on coil on RIC. Both the time and frequency characteristics of the RIC were seen to vary with the MRI RF coil used. The copper windings of the RF coils were isolated as the main source of RIC. A linear dependence on dose rate was seen. The RIC was decreased with wax buildup, suggesting an electronic disequilibrium as the cause of RIC. This study shows a measurable RIC present in MRI RF coils. This unwanted current could be possibly detrimental to the signal to noise ratio in MRI and produce image artifacts. PMID:20071754

  7. Radiation risks in lung cancer screening programs: a comparison with nuclear industry workers and atomic bomb survivors.

    PubMed

    McCunney, Robert J; Li, Jessica

    2014-03-01

    The National Lung Cancer Screening Trial (NLST) demonstrated that screening with low-dose CT (LDCT) scan reduced lung cancer and overall mortality by 20% and 7%, respectively. The LDCT scanning involves an approximate 2-mSv dose, whereas full-chest CT scanning, the major diagnostic study used to follow up nodules, may involve a dose of 8 mSv. Radiation associated with CT scanning and other diagnostic studies to follow up nodules may present an independent risk of lung cancer. On the basis of the NLST, we estimated the incidence and prevalence of nodules detected in screening programs. We followed the Fleischner guidelines for follow-up of nodules to assess cumulative radiation exposure over 20- and 30-year periods. We then evaluated nuclear worker cohort studies and atomic bomb survivor studies to assess the risk of lung cancer from radiation associated with long-term lung cancer screening programs. The findings indicate that a 55-year-old lung screening participant may experience a cumulative radiation exposure of up to 280 mSv over a 20-year period and 420 mSv over 30 years. These exposures exceed those of nuclear workers and atomic bomb survivors. This assessment suggests that long-term (20-30 years) LDCT screening programs are associated with nontrivial cumulative radiation doses. Current lung cancer screening protocols, if conducted over 20- to 30-year periods, can independently increase the risk of lung cancer beyond cigarette smoking as a result of cumulative radiation exposure. Radiation exposures from LDCT screening and follow-up diagnostic procedures exceed lifetime radiation exposures among nuclear power workers and atomic bomb survivors.

  8. Immunological Aspect of Radiation-Induced Pneumonitis, Current Treatment Strategies, and Future Prospects

    PubMed Central

    Kainthola, Anup; Haritwal, Teena; Tiwari, Mrinialini; Gupta, Noopur; Parvez, Suhel; Tiwari, Manisha; Prakash, Hrideysh; Agrawala, Paban K.

    2017-01-01

    Delivery of high doses of radiation to thoracic region, particularly with non-small cell lung cancer patients, becomes difficult due to subsequent complications arising in the lungs of the patient. Radiation-induced pneumonitis is an early event evident in most radiation exposed patients observed within 2–4 months of treatment and leading to fibrosis later. Several cytokines and inflammatory molecules interplay in the vicinity of the tissue developing radiation injury leading to pneumonitis and fibrosis. While certain cytokines may be exploited as biomarkers, they also appear to be a potent target of intervention at transcriptional level. Initiation and progression of pneumonitis and fibrosis thus are dynamic processes arising after few months to year after irradiation of the lung tissue. Currently, available treatment strategies are challenged by the major dose limiting complications that curtails success of the treatment as well as well being of the patient’s future life. Several approaches have been in practice while many other are still being explored to overcome such complications. The current review gives a brief account of the immunological aspects, existing management practices, and suggests possible futuristic approaches. PMID:28512460

  9. 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.

  10. 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.

  11. Food allergy and risk assessment: Current status and future directions

    NASA Astrophysics Data System (ADS)

    Remington, Benjamin C.

    2017-09-01

    Risk analysis is a three part, interactive process that consists of a scientific risk assessment, a risk management strategy and an exchange of information through risk communication. Quantitative risk assessment methodologies are now available and widely used for assessing risks regarding the unintentional consumption of major, regulated allergens but new or modified proteins can also pose a risk of de-novo sensitization. The risks due to de-novo sensitization to new food allergies are harder to quantify. There is a need for a systematic, comprehensive battery of tests and assessment strategy to identify and characterise de-novo sensitization to new proteins and the risks associated with them. A risk assessment must be attuned to answer the risk management questions and needs. Consequently, the hazard and risk assessment methods applied and the desired information are determined by the requested outcome for risk management purposes and decisions to be made. The COST Action network (ImpARAS, www.imparas.eu) has recently started to discuss these risk management criteria from first principles and will continue with the broader subject of improving strategies for allergen risk assessment throughout 2016-2018/9.

  12. Health risks of exposure to non-ionizing radiation--myths or science-based evidence.

    PubMed

    Hietanen, Maila

    2006-01-01

    The non-ionizing radiation (NIR) contains large range of wavelengths and frequencies from vacuum ultraviolet (UV) radiation to static electric and magnetic fields. Biological effects of electromagnetic (EM) radiation depend greatly on wavelength and other physical parameters. The Sun is the most significant source of environmental UV exposure, so that outdoor workers are at risk of chronic over-exposure. Also exposure to short-wave visible light is associated with the aging and degeneration of the retina. Especially hazardous are laser beams focused to a small spot at the retina, resulting in permanent visual impairment. Exposure to EM fields induces body currents and energy absorption in tissues, depending on frequencies and coupling mechanisms. Thermal effects caused by temperature rise are basically understood, whereas the challenge is to understand the suspected non-thermal effects. Radiofrequency (RF) fields around frequencies of 900 MHz and 1800 MHz are of special interest because of the rapid advances in the telecommunication technology. The field levels of these sources are so low that temperature rise is unlikely to explain possible health effects. Other mechanisms of interaction have been proposed, but biological experiments have failed to confirm their existence.

  13. Redundant drive current imbalance problem of the Automatic Radiator Inspection Device (ARID)

    NASA Technical Reports Server (NTRS)

    Latino, Carl D.

    1992-01-01

    The Automatic Radiator Inspection Device (ARID) is a 4 Degree of Freedom (DOF) robot with redundant drive motors at each joint. The device is intended to automate the labor intensive task of space shuttle radiator inspection. For safety and redundancy, each joint is driven by two independent motor systems. Motors driving the same joint, however, draw vastly different currents. The concern was that the robot joints could be subjected to undue stress. It was the objective of this summer's project to determine the cause of this current imbalance. In addition it was to determine, in a quantitative manner, what was the cause, how serious the problem was in terms of damage or undue wear to the robot and find solutions if possible. It was concluded that most problems could be resolved with a better motor control design. This document discusses problems encountered and possible solutions.

  14. Redundant drive current imbalance problem of the Automatic Radiator Inspection Device (ARID)

    NASA Astrophysics Data System (ADS)

    Latino, Carl D.

    1992-09-01

    The Automatic Radiator Inspection Device (ARID) is a 4 Degree of Freedom (DOF) robot with redundant drive motors at each joint. The device is intended to automate the labor intensive task of space shuttle radiator inspection. For safety and redundancy, each joint is driven by two independent motor systems. Motors driving the same joint, however, draw vastly different currents. The concern was that the robot joints could be subjected to undue stress. It was the objective of this summer's project to determine the cause of this current imbalance. In addition it was to determine, in a quantitative manner, what was the cause, how serious the problem was in terms of damage or undue wear to the robot and find solutions if possible. It was concluded that most problems could be resolved with a better motor control design. This document discusses problems encountered and possible solutions.

  15. Low Dose Radiation Cancer Risks: Epidemiological and Toxicological Models

    SciTech Connect

    David G. Hoel, PhD

    2012-04-19

    The basic purpose of this one year research grant was to extend the two stage clonal expansion model (TSCE) of carcinogenesis to exposures other than the usual single acute exposure. The two-stage clonal expansion model of carcinogenesis incorporates the biological process of carcinogenesis, which involves two mutations and the clonal proliferation of the intermediate cells, in a stochastic, mathematical way. The current TSCE model serves a general purpose of acute exposure models but requires numerical computation of both the survival and hazard functions. The primary objective of this research project was to develop the analytical expressions for the survival function and the hazard function of the occurrence of the first cancer cell for acute, continuous and multiple exposure cases within the framework of the piece-wise constant parameter two-stage clonal expansion model of carcinogenesis. For acute exposure and multiple exposures of acute series, it is either only allowed to have the first mutation rate vary with the dose, or to have all the parameters be dose dependent; for multiple exposures of continuous exposures, all the parameters are allowed to vary with the dose. With these analytical functions, it becomes easy to evaluate the risks of cancer and allows one to deal with the various exposure patterns in cancer risk assessment. A second objective was to apply the TSCE model with varing continuous exposures from the cancer studies of inhaled plutonium in beagle dogs. Using step functions to estimate the retention functions of the pulmonary exposure of plutonium the multiple exposure versions of the TSCE model was to be used to estimate the beagle dog lung cancer risks. The mathematical equations of the multiple exposure versions of the TSCE model were developed. A draft manuscript which is attached provides the results of this mathematical work. The application work using the beagle dog data from plutonium exposure has not been completed due to the fact

  16. Ultraviolet Radiation and Melanoma: AN Interdisciplinary Risk Assessment

    NASA Astrophysics Data System (ADS)

    Charache, Darryl H.

    1995-01-01

    A multidisciplinary study involving atmospheric, demographic, and epidemiologic disciplines has been conducted to investigate the relation between ultraviolet (UV) dose and melanoma incidence rate on a global scale. A multiple scattering radiative transfer model has been developed to estimate spectral irradiance and integrated biologically effective dose amounts in the UV-B and UV-A wavelength regime. Global maps of seasonally averaged and peak biologically effective dose on a 1^circ x 1^circ resolution have been created for significant land areas using satellite- and surface-derived atmospheric and topographic data sets. These maps have been coupled with worldwide melanoma incidence rates obtained from the International Agency for Research on Cancer (IARC) database and an ethnically-derived skin type classification system to estimate a "global" biological amplification factor (BAF) for males and females. With these BAFs, future estimates of incidence rates and number of additional melanoma cases that may be expected based on simulated increases in UV dose between the years 1980 -2000 can be estimated under simplifying atmospheric and demographic assumptions. Using worldwide melanoma rates and corresponding UV doses, BAFs of 1.67 and 1.26 were derived for white males and females, respectively. No significant relation was found for non-white skin types. Despite relatively low current incidence rates, projections indicate greater percentage changes in incidence rates at higher latitudes where downward trends in ozone are highest. Greater increases in total number of cases appear in countries having high white skin populations; the increase in total cases in these countries is due primarily to population size rather than estimated increases in UV dose. The integration of atmospheric, epidemiological, and demographic models in this study has established a framework that can be used to improve assessments when more data become available, and can be adapted to analyze

  17. Current opinions on medical radiation: a survey of oncologists regarding radiation exposure and dose reduction in oncology patients.

    PubMed

    Burke, Lauren M B; Bashir, Mustafa R; Neville, Amy M; Nelson, Rendon C; Jaffe, Tracy A

    2014-05-01

    The aim of this study was to evaluate oncologists' opinions about the use of ionizing radiation in medical imaging of oncology patients. An electronic survey was e-mailed to 2,725 oncologists at the top 50 National Cancer Institute-funded cancer centers. The survey focused on opinions on CT dose reduction in oncology patients and current philosophies behind long-term imaging in these patients. The response rate was 15% (415 of 2,725). Eighty-two percent of respondents stated that their patients or families have expressed anxiety regarding radiation dose from medical imaging. Although fewer than half of oncologists (48%) did not know whether CT dose reduction techniques were used at their institutions, only 25% were concerned that small lesions may be missed with low-dose CT techniques. The majority of oncologists (63%) follow National Comprehensive Cancer Network guidelines for imaging follow-up, while the remainder follow other national guidelines such as those of the Children's Oncology Group, the American Society of Clinical Oncology, or clinical trials. Ninety percent of respondents believe that long-term surveillance in oncology patients is warranted, particularly in patients with breast cancer, melanoma, sarcoma, and pediatric malignancies. The majority of oncologists would consider the use of low-dose CT imaging in specific patient populations: (1) children and young women, (2) those with malignancies that do not routinely metastasize to the liver, and (3) patients undergoing surveillance imaging. Cumulative radiation exposure is a concern for patients and oncologists. Among oncologists, there is support for long-term imaging surveillance despite lack of national guidelines. Published by Elsevier Inc.

  18. Perspective on the use of LNT for radiation protection and risk assessment by the U.S. Environmental Protection Agency.

    PubMed

    Puskin, Jerome S

    2009-08-21

    The U.S. Environmental Protection Agency (EPA) bases its risk assessments, regulatory limits, and nonregulatory guidelines for population exposures to low level ionizing radiation on the linear no-threshold (LNT) hypothesis, which assumes that the risk of cancer due to a low dose exposure is proportional to dose, with no threshold. The use of LNT for radiation protection purposes has been repeatedly endorsed by authoritative scientific advisory bodies, including the National Academy of Sciences' BEIR Committees, whose recommendations form a primary basis of EPA's risk assessment methodology. Although recent radiobiological findings indicate novel damage and repair processes at low doses, LNT is supported by data from both epidemiology and radiobiology. Given the current state of the science, the consensus positions of key scientific and governmental bodies, as well as the conservatism and calculational convenience of the LNT assumption, it is unlikely that EPA will modify this approach in the near future.

  19. Perception of Radiation Risk by Japanese Radiation Specialists Evaluated as a Safe Dose Before the Fukushima Nuclear Accident.

    PubMed

    Miura, Miwa; Ono, Koji; Yamauchi, Motohiro; Matsuda, Naoki

    2016-06-01

    From October to December 2010, just before the radiological accident at the Fukushima Daiichi nuclear power plant, 71 radiation professionals from radiation facilities in Japan were asked what they considered as a "safe dose" of radiation for themselves, their partners, parents, children, siblings, and friends. Although the 'safe dose' they noted varied widely, from less than 1 mSv y to more than 100 mSv y, the average dose was 35.6 mSv y, which is around the middle point between the legal exposure dose limits for the annual average and for any single year. Similar results were obtained from other surveys of members of the Japan Radioisotope Association (36.9 mSv y) and of the Oita Prefectural Hospital (36.8 mSv y). Among family members and friends, the minimum average "safe" dose was 8.5 mSv y for children, for whom 50% of the responders claimed a "safe dose" of less than 1 mSv. Gender, age and specialty of the radiation professional also affected their notion of a "safe dose." These findings suggest that the perception of radiation risk varies widely even for radiation professionals and that the legal exposure dose limits derived from regulatory science may act as an anchor of safety. The different levels of risk perception for different target groups among radiation professionals appear similar to those in the general population. The gap between these characteristics of radiation professionals and the generally accepted picture of radiation professionals might have played a role in the state of confusion after the radiological accident.

  20. Communication of radiation risk in nuclear medicine: Are we saying the right thing?

    PubMed

    Pandit, Manish; Vinjamuri, Sobhan

    2014-07-01

    The radiation risk arising from nuclear medicine investigations represents a small but manageable risk to patients and it needs to be effectively communicated to them. Frequently in the culture of "doctor knows best," patients trust their doctors to do whatever is right and appropriate and leave it to them to worry about any attendant risks associated with any tests involving the use of radiation. The benefit to the patient of having a speedier diagnosis and a further guide to management may not be effectively communicated in a comprehensive, timely and professional manner. In this article, we address the issue of communication of radiation risk and benefits to patients and the basis for such information. While there are different ways of communicating radiation risk, we recognize that certain basic parameters are absolutely essential for patients to enable them to make an informed choice about undergoing a nuclear medicine investigation under the direction of a well-trained and qualified individual.

  1. [Current status on storage, processing and risk communication of medical radioactive waste in Japan].

    PubMed

    Watanabe, Hiroshi; Yamaguchi, Ichiro; Kida, Tetsuo; Hiraki, Hitoshi; Fujibuchi, Toshioh; Maehara, Yoshiaki; Tsukamoto, Atsuko; Koizumi, Mitsue; Kimura, Yumi; Horitsugi, Genki

    2013-03-01

    Decay-in-storage for radioactive waste including that of nuclear medicine has not been implemented in Japan. Therefore, all medical radioactive waste is collected and stored at the Japan Radioisotope Association Takizawa laboratory, even if the radioactivity has already decayed out. To clarify the current situation between Takizawa village and Takizawa laboratory, we investigated the radiation management status and risk communication activities at the laboratory via a questionnaire and site visiting survey in June 2010. Takizawa laboratory continues to maintain an interactive relationship with local residents. As a result, Takizawa village permitted the acceptance of new medical radioactive waste containing Sr-89 and Y-90. However, the village did not accept any non-medical radioactive waste such as waste from research laboratories. To implement decay-in-storage in Japan, it is important to obtain agreement with all stakeholders. We must continue to exert sincere efforts to acquire the trust of all stakeholders.

  2. An Overview of NASA's Risk of Cardiovascular Disease from Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Patel, Zarana S.; Huff, Janice L.; Simonsen, Lisa C.

    2015-01-01

    The association between high doses of radiation exposure and cardiovascular damage is well established. Patients that have undergone radiotherapy for primary cancers of the head and neck and mediastinal regions have shown increased risk of heart and vascular damage and long-term development of radiation-induced heart disease [1]. In addition, recent meta-analyses of epidemiological data from atomic bomb survivors and nuclear industry workers has also shown that acute and chronic radiation exposures is strongly correlated with an increased risk of circulatory disease at doses above 0.5 Sv [2]. However, these analyses are confounded for lower doses by lifestyle factors, such as drinking, smoking, and obesity. The types of radiation found in the space environment are significantly more damaging than those found on Earth and include galactic cosmic radiation (GCR), solar particle events (SPEs), and trapped protons and electrons. In addition to the low-LET data, only a few studies have examined the effects of heavy ion radiation on atherosclerosis, and at lower, space-relevant doses, the association between exposure and cardiovascular pathology is more varied and unclear. Understanding the qualitative differences in biological responses produced by GCR compared to Earth-based radiation is a major focus of space radiation research and is imperative for accurate risk assessment for long duration space missions. Other knowledge gaps for the risk of radiation-induced cardiovascular disease include the existence of a dose threshold, low dose rate effects, and potential synergies with other spaceflight stressors. The Space Radiation Program Element within NASA's Human Research Program (HRP) is managing the research and risk mitigation strategies for these knowledge gaps. In this presentation, we will review the evidence and present an overview of the HRP Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation Exposure.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Current and Proposed Regulations Related to Minimum Risk Pesticides

    EPA Pesticide Factsheets

    Minimum risk pesticides are exempted from requirements for registration with EPA but are still subject to certain criteria to qualify as minimum risk and may be further regulated by states. See links to the key regulatory citations.

  8. Poster - Thur Eve - 19: Risk assessment of clinical radiation processes using failure modes and effect analysis.

    PubMed

    Angers, C; Studinski, R; La Russa, D; Bahm, J; Renaud, J; Clark, B G

    2012-07-01

    The aim of this work was to apply failure modes and effect analysis (FMEA) to assess risk in two radiation planning and treatment processes; our on-call (out-of-clinical hours) process and our tomotherapy process. The motivation was provided by analysis of 2506 adverse incidents reported over a 5 year period, the on-call process for giving rise to a higher than expected number of incidents and our tomotherapy process for the reverse. For the on-call scenario, three separate processes were analysed: our current process, our current process incorporating a software upgrade eliminating several planning steps and a fully integrated process in which the patient is imaged, planned and treated on a single platform (TomoTherapy Hi Art, Accuray Incorporated, Sunnyvale, CA). After construction of a detailed process map for each case, a multidisciplinary group identified potential failure modes for each process step, the effects of each failure and existing controls. Risk probability numbers were determined from severity, frequency of occurrence and detectability scores assigned to each failure mode according to a standard scale. The results were analysed to identify and prioritise feasible and effective process improvements. For the on-call process, our current workflow was identified as incurring the highest risk of the three processes analysed, demonstrating quantitatively the value of the software upgrade and providing a clear rationale for the associated expense. In summary, we have found FMEA to be a feasible tool for assessing relative risk in a clinical process. However, operational and resource issues must be considered separately. © 2012 American Association of Physicists in Medicine.

  9. Radiation protection information: can you trust the government's risks or risk the government's trust?: 1997 G. William Morgan lecture.

    PubMed

    Ziemer, P L

    1999-07-01

    Public acceptance of information concerning radiation risks has been impacted by the erosion of trust in government agencies and by societal images that personify radiation or its effects in terms of monsters and ogres. The loss of trust in government agencies, particularly the Atomic Energy Commission and later the Department of Energy, has been influenced by a number of key events and individuals. Examples of these are given, including the anti-Viet Nam war movement, the Watergate incident, the activities of the Union of Concerned Scientists, Ralph Nader and the Critical Mass movement, the claims of Ernest Sternglass, and the widely publicized views of John Gofman and Arthur Tamplin. The use of negative images, pictures, and symbols in the mass media has reinforced the public perception of radiation as a thing to be feared. There is growing evidence that the public perception of radiation risks is related more to mistrust and negative images than it is to the technical information health physicists provide or to the issue of whether or not the linear no-threshold theory of radiation risks is correct. Attempts by federal agencies to regain public trust in radiation risk information generated by health physicists or other radiation scientists appear to be largely unsuccessful. If health physicists hope to be successful in changing such public perceptions, they may have to focus efforts on the next generation and concentrate on assuring that elementary and secondary school children receive sound instruction on radiation risks. Additional research at the molecular biology level is needed to elucidate the risks, if any, at low doses so that the practice of extrapolating low dose responses from high dose data can be eliminated.

  10. Relationship between radiation exposure and risk of second primary cancers among atomic bomb survivors.

    PubMed

    Li, Christopher I; Nishi, Nobuo; McDougall, Jean A; Semmens, Erin O; Sugiyama, Hiromi; Soda, Midori; Sakata, Ritsu; Hayashi, Mikiko; Kasagi, Fumiyoshi; Suyama, Akihiko; Mabuchi, Kiyohiko; Davis, Scott; Kodama, Kazunori; Kopecky, Kenneth J

    2010-09-15

    Radiation exposure is related to risk of numerous types of cancer, but relatively little is known about its effect on risk of multiple primary cancers. Using follow-up data through 2002 from 77,752 Japanese atomic bomb survivors, we identified 14,048 participants diagnosed with a first primary cancer, of whom 1,088 were diagnosed with a second primary cancer. Relationships between radiation exposure and risks of first and second primary cancers were quantified using Poisson regression. There was a similar linear dose-response relationship between radiation exposure and risks of both first and second primary solid tumors [excess relative risk (ERR)/Gy = 0.65; 95% confidence interval (CI), 0.57-0.74 and ERR/Gy = 0.56; 95% CI, 0.33-0.80, respectively] and risk of both first and second primary leukemias (ERR/Gy = 2.65; 95% CI, 1.78-3.78 and ERR/Gy = 3.65; 95% CI, 0.96-10.70, respectively). Background incidence rates were higher for second solid cancers, compared with first solid cancers, until about age 70 years for men and 80 years for women (P < 0.0001), but radiation-related ERRs did not differ between first and second primary solid cancers (P = 0.70). Radiation dose was most strongly related to risk of solid tumors that are radiation-sensitive including second primary lung, colon, female breast, thyroid, and bladder cancers. Radiation exposure confers equally high relative risks of second primary cancers as first primary cancers. Radiation is a potent carcinogen and those with substantial exposures who are diagnosed with a first primary cancer should be carefully screened for second primary cancers, particularly for cancers that are radiation-sensitive.

  11. A self-powered thin-film radiation detector using intrinsic high-energy current

    SciTech Connect

    Zygmanski, Piotr E-mail: Erno-Sajo@uml.edu; Sajo, Erno E-mail: Erno-Sajo@uml.edu

    2016-01-15

    Purpose: The authors introduce a radiation detection method that relies on high-energy current (HEC) formed by secondary charged particles in the detector material, which induces conduction current in an external readout circuit. Direct energy conversion of the incident radiation powers the signal formation without the need for external bias voltage or amplification. The detector the authors consider is a thin-film multilayer device, composed of alternating disparate electrically conductive and insulating layers. The optimal design of HEC detectors consists of microscopic or nanoscopic structures. Methods: Theoretical and computational developments are presented to illustrate the salient properties of the HEC detector and to demonstrate its feasibility. In this work, the authors examine single-sandwiched and periodic layers of Cu and Al, and Au and Al, ranging in thickness from 100 nm to 300 μm and separated by similarly sized dielectric gaps, exposed to 120 kVp x-ray beam (half-value thickness of 4.1 mm of Al). The energy deposition characteristics and the high-energy current were determined using radiation transport computations. Results: The authors found that in a dual-layer configuration, the signal is in the measurable range. For a defined total detector thickness in a multilayer structure, the signal sharply increases with decreasing thickness of the high-Z conductive layers. This paper focuses on the computational results while a companion paper reports the experimental findings. Conclusions: Significant advantages of the device are that it does not require external power supply and amplification to create a measurable signal; it can be made in any size and geometry, including very thin (sub-millimeter to submicron) flexible curvilinear forms, and it is inexpensive. Potential applications include medical dosimetry (both in vivo and external), radiation protection, and other settings where one or more of the above qualities are desired.

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

    PubMed

    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

    2015-07-01

    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. 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. 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). This study provides strong evidence of positive associations between protracted low-dose radiation exposure and leukaemia. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. 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

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

    NASA Astrophysics Data System (ADS)

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

    This presentation evaluates differences between radiation biomarkers of dose and risk and demonstrates the consequential problems associated with using biomarkers to do risk calculations following radiation exposures to the complex radiation environment found in deep space. Dose is a physical quantity, while risk is a biological quantity. Dose does not predict risk. This manuscript discusses species sensitivity factors, tissue weighting factors, and radiation quality factors derived from relative biological effectiveness (RBE). These factors are used to modify dose to make it a better predictor of risk. At low doses, where it is not possible to measure changes in risk, biomarkers have been used incorrectly as an intermediate step in predicting risk. Examples of biomarkers that do not predict risk are reviewed. Species sensitivity factors were evaluated using the Syrian hamster and the Wistar rat. Although the frequency of chromosome damage is very similar in these two species, the Wistar rat is very sensitive to radiation-induced lung cancer while the Syrian hamster is very resistant. To illustrate problems involved in using tissue weighting factors, rat trachea and deep lung tissues were compared. The similar level of chromosome damage observed in these two tissues would predict that the risk for cancer induction would be the same. However, even though large numbers of deep lung tumors result from inhaled radon, under the same exposure conditions there has never been a tracheal tumor observed. Finally, the Relative Biological Effectiveness (RBE) used to generate "quality factors" that convert exposure and dose from different types of radiation to a single measure of risk, is discussed. Important risk comparisons are done at very low doses, where the response to the reference radiation has been shown to either increase or decrease as a function of dose. Thus, the RBE and the subsequent risk predicted is more dependent on the background response of the endpoint and

  15. Risk of mortality from circulatory diseases in Mayak workers cohort following occupational radiation exposure.

    PubMed

    Azizova, T V; Grigorieva, E S; Hunter, N; Pikulina, M V; Moseeva, M B

    2015-09-01

    Mortality from circulatory diseases (CD) (ICD-9 codes 390-459) was studied in an extended Mayak worker cohort, which included 22,377 workers first employed at the Mayak Production Association in 1948-1982 and followed up to the end of 2008. The enlarged cohort and extended follow-up as compared to the previous analyses provided an increased number of deaths from CD and improved statistical power of this mortality study. The analyses were based on dose estimates provided by a new Mayak Worker Dosimetry System 2008 (MWDS-2008). For the first time in the study of non-cancer effects in this cohort quantitative smoking data (smoking index) were taken into account. A significant increasing trend for CD mortality with increasing dose from external gamma-rays was found after having adjusted for non-radiation factors; the excess relative risk per unit dose (ERR/Gy) was 0.05 (95% confidence interval (CI):  >0, 0.11). Inclusion of an additional adjustment for dose from internal alpha-radiation to the liver resulted in a two-fold increase of ERR/Gy = 0.10 (95% CI: 0.02, 0.21). A significant increasing trend in CD mortality with increasing dose from internal alpha-radiation to the liver was observed (ERR/Gy = 0.27, 95% CI: 0.12, 0.48). However the ERR/Gy decreased and lost its significance after adjusting for dose from external gamma-rays. Results of the current study are in good agreement with risk estimates obtained for the Japanese LSS cohort as well as other studies of cohorts of nuclear workers.

  16. Understanding the Dynamical Evolution of the Earth Radiation Belt and Ring Current Coupled System

    NASA Astrophysics Data System (ADS)

    Shprits, Yuri; Usanova, Maria; Kellerman, Adam; Drozdov, Alexander

    2016-07-01

    Modeling and understanding the ring current and radiation belt-coupled system has been a grand challenge since the beginning of the space age. In this study we show long-term simulations with a 3D Versatile Electron Radiation Belt (VERB) code of modeling the radiation belts with boundary conditions derived from observations around geosynchronous orbit. Simulations can reproduce long term variations of the electron radiation belt fluxes and show the importance of local acceleration, radial diffusion, loss to the atmosphere and loss to the magnetopause. We also present 4D VERB simulations that include convective transport, radial diffusion, pitch angle scattering and local acceleration. VERB simulations show that the lower energy inward transport is dominated by the convection and higher energy transport is dominated by the diffusive radial transport. We also show that at energies of 100s of keV, a number of processes work simultaneously, including convective transport, radial diffusion, local acceleration, loss to the loss cone and loss to the magnetopause. The results of the simulation of the March 2013 storm are compared with Van Allen Probes observations.

  17. Modifiable risk factors of ecstasy use: risk perception, current dependence, perceived control, and depression

    PubMed Central

    Leung, Kit Sang; Ben Abdallah, Arbi; Cottler, Linda B.

    2009-01-01

    Risk perception, perceived behavioral control of obtaining ecstasy (PBC-obtaining), current ecstasy dependence, and recent depression have been associated with past ecstasy use, however, their utility in predicting ecstasy use has not been demonstrated. This study aimed to determine whether these four modifiable risk factors could predict ecstasy use after controlling for socio-demographic covariates and recent polydrug use. Data from 601 ecstasy users in the National Institute on Drug Abuse funded TriCity Study of Club Drug Use, Abuse and Dependence were analyzed using multivariate logistic regression. Participants were interviewed twice within a 2-week period using standardized instruments. Thirteen percent (n=80) of the participants reported using ecstasy between the two interviews. Low risk perception, high PBC-obtaining (an estimated ecstasy procurement time < 24 hours), and current ecstasy dependence were statistically associated with ecstasy use between the two interviews. Recent depression was not a significant predictor. Despite not being a target predictor, recent polydrug use was also statistically associated with ecstasy use. The present findings may inform the development of interventions targeting ecstasy users. PMID:19880258

  18. Modifiable risk factors of ecstasy use: risk perception, current dependence, perceived control, and depression.

    PubMed

    Leung, Kit Sang; Ben Abdallah, Arbi; Copeland, Jan; Cottler, Linda B

    2010-03-01

    Risk perception, perceived behavioral control of obtaining ecstasy (PBC-obtaining), current ecstasy dependence, and recent depression have been associated with past ecstasy use, however, their utility in predicting ecstasy use has not been demonstrated. This study aimed to determine whether these four modifiable risk factors could predict ecstasy use after controlling for socio-demographic covariates and recent polydrug use. Data from 601 ecstasy users in the National Institute on Drug Abuse-funded TriCity Study of Club Drug Use, Abuse and Dependence were analyzed using multivariate logistic regression. Participants were interviewed twice within a 2-week period using standardized instruments. Thirteen percent (n = 80) of the participants reported using ecstasy between the two interviews. Low risk perception, high PBC-obtaining (an estimated ecstasy procurement time < 24h), and current ecstasy dependence were statistically associated with ecstasy use between the two interviews. Recent depression was not a significant predictor. Despite not being a target predictor, recent polydrug use was also statistically associated with ecstasy use. The present findings may inform the development of interventions targeting ecstasy users.

  19. New risk metrics and mathematical tools for risk analysis: Current and future challenges

    NASA Astrophysics Data System (ADS)

    Skandamis, Panagiotis N.; Andritsos, Nikolaos; Psomas, Antonios; Paramythiotis, Spyridon

    2015-01-01

    The current status of the food safety supply world wide, has led Food and Agriculture Organization (FAO) and World Health Organization (WHO) to establishing Risk Analysis as the single framework for building food safety control programs. A series of guidelines and reports that detail out the various steps in Risk Analysis, namely Risk Management, Risk Assessment and Risk Communication is available. The Risk Analysis approach enables integration between operational food management systems, such as Hazard Analysis Critical Control Points, public health and governmental decisions. To do that, a series of new Risk Metrics has been established as follows: i) the Appropriate Level of Protection (ALOP), which indicates the maximum numbers of illnesses in a population per annum, defined by quantitative risk assessments, and used to establish; ii) Food Safety Objective (FSO), which sets the maximum frequency and/or concentration of a hazard in a food at the time of consumption that provides or contributes to the ALOP. Given that ALOP is rather a metric of the public health tolerable burden (it addresses the total `failure' that may be handled at a national level), it is difficult to be interpreted into control measures applied at the manufacturing level. Thus, a series of specific objectives and criteria for performance of individual processes and products have been established, all of them assisting in the achievement of FSO and hence, ALOP. In order to achieve FSO, tools quantifying the effect of processes and intrinsic properties of foods on survival and growth of pathogens are essential. In this context, predictive microbiology and risk assessment have offered an important assistance to Food Safety Management. Predictive modelling is the basis of exposure assessment and the development of stochastic and kinetic models, which are also available in the form of Web-based applications, e.g., COMBASE and Microbial Responses Viewer), or introduced into user-friendly softwares

  20. New risk metrics and mathematical tools for risk analysis: Current and future challenges

    SciTech Connect

    Skandamis, Panagiotis N. Andritsos, Nikolaos Psomas, Antonios Paramythiotis, Spyridon

    2015-01-22

    The current status of the food safety supply world wide, has led Food and Agriculture Organization (FAO) and World Health Organization (WHO) to establishing Risk Analysis as the single framework for building food safety control programs. A series of guidelines and reports that detail out the various steps in Risk Analysis, namely Risk Management, Risk Assessment and Risk Communication is available. The Risk Analysis approach enables integration between operational food management systems, such as Hazard Analysis Critical Control Points, public health and governmental decisions. To do that, a series of new Risk Metrics has been established as follows: i) the Appropriate Level of Protection (ALOP), which indicates the maximum numbers of illnesses in a population per annum, defined by quantitative risk assessments, and used to establish; ii) Food Safety Objective (FSO), which sets the maximum frequency and/or concentration of a hazard in a food at the time of consumption that provides or contributes to the ALOP. Given that ALOP is rather a metric of the public health tolerable burden (it addresses the total ‘failure’ that may be handled at a national level), it is difficult to be interpreted into control measures applied at the manufacturing level. Thus, a series of specific objectives and criteria for performance of individual processes and products have been established, all of them assisting in the achievement of FSO and hence, ALOP. In order to achieve FSO, tools quantifying the effect of processes and intrinsic properties of foods on survival and growth of pathogens are essential. In this context, predictive microbiology and risk assessment have offered an important assistance to Food Safety Management. Predictive modelling is the basis of exposure assessment and the development of stochastic and kinetic models, which are also available in the form of Web-based applications, e.g., COMBASE and Microbial Responses Viewer), or introduced into user

  1. End-To-End Risk Assesment: From Genes and Protein to Acceptable Radiation Risks for Mars Exploration

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Schimmerling, Walter

    2000-01-01

    The human exploration of Mars will impose unavoidable health risks from galactic cosmic rays (GCR) and possibly solar particle events (SPE). It is the goal of NASA's Space Radiation Health Program to develop the capability to predict health risks with significant accuracy to ensure that risks are well below acceptable levels and to allow for mitigation approaches to be effective at reasonable costs. End-to-End risk assessment is the approach being followed to understand proton and heavy ion damage at the molecular, cellular, and tissue levels in order to predict the probability of the major health risk including cancer, neurological disorders, hereditary effects, cataracts, and acute radiation sickness and to develop countermeasures for mitigating risks.

  2. End-To-End Risk Assesment: From Genes and Protein to Acceptable Radiation Risks for Mars Exploration

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Schimmerling, Walter

    2000-01-01

    The human exploration of Mars will impose unavoidable health risks from galactic cosmic rays (GCR) and possibly solar particle events (SPE). It is the goal of NASA's Space Radiation Health Program to develop the capability to predict health risks with significant accuracy to ensure that risks are well below acceptable levels and to allow for mitigation approaches to be effective at reasonable costs. End-to-End risk assessment is the approach being followed to understand proton and heavy ion damage at the molecular, cellular, and tissue levels in order to predict the probability of the major health risk including cancer, neurological disorders, hereditary effects, cataracts, and acute radiation sickness and to develop countermeasures for mitigating risks.

  3. Outdoor sports and risk of ultraviolet radiation-related skin lesions in children: evaluation of risks and prevention.

    PubMed

    Mahé, E; Beauchet, A; de Paula Corrêa, M; Godin-Beekmann, S; Haeffelin, M; Bruant, S; Fay-Chatelard, F; Jégou, F; Saiag, P; Aegerter, P

    2011-08-01

    Excessive ultraviolet (UV) radiation exposure can cause skin cancers, skin photoageing and cataracts. Children are targeted by sun-protection campaigns because high sun exposure and sunburn in childhood increase the risk of melanoma in adulthood. Little information is available about UV radiation risk and exposure in children who take part in outdoor sports. To evaluate the risk of developing UV radiation-induced skin lesions run by children who practise outdoor sports, and UV radiation exposure and sun-protection measures during a soccer tournament. Firstly, we evaluated the relationship between melanocytic naevus - a skin lesion linked with exposure to UV radiation - and outdoor sports in 660 11-year-old children. Secondly, we used the occasion of a 1-day soccer tournament held in the spring to evaluate UV radiation-protective measures used by soccer players and the public. We also evaluated the UV radiation index and cloud cover during the tournament, and calculated the UV radiation dose and minimal erythema dose depending on skin phototype. The naevus count and acquired naevus count measured over the 2 years of the study were higher in the 344 children who practised outdoor sports. Sun-protective measures were insufficient for soccer players and the public. This study shows that outdoor sports increase the risk of developing UV radiation-induced skin lesions in childhood. During a 1-day soccer tournament held in the spring, children and their parents were inadequately protected against the sun. These results suggest that sun-protection campaigns should be aimed at children who practise popular outdoor sports. © 2011 The Authors. BJD © 2011 British Association of Dermatologists 2011.

  4. 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

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

    PubMed Central

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

    2011-01-01

    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 (CTDIvol) 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 patients

  6. Effective Patient Education in Medical Imaging: Public Perceptions of Radiation Exposure Risk.

    ERIC Educational Resources Information Center

    Ludwig, Rebecca L.; Turner, Lori W.

    2002-01-01

    In a cross-sectional survey of 200 adults, less than half agreed with experts on the risks of radiation exposure; 75-90% thought that medical imaging providers should be highly regulated; and less than one-quarter knew that most radiation damage is not permanent. (SK)

  7. Effective Patient Education in Medical Imaging: Public Perceptions of Radiation Exposure Risk.

    ERIC Educational Resources Information Center

    Ludwig, Rebecca L.; Turner, Lori W.

    2002-01-01

    In a cross-sectional survey of 200 adults, less than half agreed with experts on the risks of radiation exposure; 75-90% thought that medical imaging providers should be highly regulated; and less than one-quarter knew that most radiation damage is not permanent. (SK)

  8. Gastrointestinal radiation injury: Symptoms, risk factors and mechanisms

    PubMed Central

    Shadad, Abobakr K; Sullivan, Frank J; Martin, Joseph D; Egan, Laurence J

    2013-01-01

    Ionising radiation therapy is a common treatment modality for different types of cancer and its use is expected to increase with advances in screening and early detection of cancer. Radiation injury to the gastrointestinal tract is important factor working against better utility of this important therapeutic modality. Cancer survivors can suffer a wide variety of acute and chronic symptoms following radiotherapy, which significantly reduces their quality of life as well as adding an extra burden to the cost of health care. The accurate diagnosis and treatment of intestinal radiation injury often represents a clinical challenge to practicing physicians in both gastroenterology and oncology. Despite the growing recognition of the problem and some advances in understanding the cellular and molecular mechanisms of radiation injury, relatively little is known about the pathophysiology of gastrointestinal radiation injury or any possible susceptibility factors that could aggravate its severity. The aims of this review are to examine the various clinical manifestations of post-radiation gastrointestinal symptoms, to discuss possible patient and treatment factors implicated in normal gastrointestinal tissue radiosensitivity and to outline different mechanisms of intestinal tissue injury. PMID:23345941

  9. Role of ULF Waves in Radiation Belt and Ring Current Dynamics

    NASA Astrophysics Data System (ADS)

    Mann, I. R.; Murphy, K. R.; Rae, I. J.; Ozeke, L.; Milling, D. K.

    2013-12-01

    Ultra-low frequency (ULF) waves in the Pc4-5 band can be excited in the magnetosphere by the solar wind. Much recent work has shown how ULF wave power is strongly correlated with solar wind speed. However, little attention has been paid the dynamics of ULF wave power penetration onto low L-shells in the inner magnetosphere. We use more than a solar cycle of ULF wave data, derived from ground-based magnetometer networks, to examine this ULF wave power penetration and its dependence on solar wind and geomagnetic activity indices. In time domain data, we show very clearly that dayside ULF wave power, spanning more than 4 orders of magnitude, follows solar wind speed variations throughout the whole solar cycle - during periods of sporadic solar maximum ICMEs, during declining phase fast solar wind streams, and at solar minimum, alike. We also show that time domain ULF wave power increases during magnetic storms activations, and significantly demonstrate that a deeper ULF wave power penetration into the inner magnetosphere occurs during larger negative excursions in Dst. We discuss potential explanations for this low-L ULF wave power penetration, including the role of plasma mass density (such as during plasmaspheric erosion), or ring current ion instabilities during near-Earth ring current penetration. Interestingly, we also show that both ULF wave power and SAMPEX MeV electron flux show a remarkable similarity in their penetration to low-L, which suggests that ULF wave power penetration may be important for understanding and explaining radiation belt dynamics. Moreover, the correlation of ULF wave power with Dst, which peaks at one day lag, suggests the ULF waves might also be important for the inward transport of ions into the ring current. Current ring current models, which exclude long period ULF wave transport, under-estimate the ring current during fast solar wind streams which is consistent with a potential role for ULF waves in ring current energisation. The

  10. Characterization of polarizing semiconductor radiation detectors by laser-induced transient currents

    NASA Astrophysics Data System (ADS)

    Musiienko, A.; Grill, R.; Pekárek, J.; Belas, E.; Praus, P.; Pipek, J.; Dědič, V.; Elhadidy, H.

    2017-08-01

    A method is presented for the determination of the carrier drift mobility, lifetime, electric field distribution, and the dynamics of space charge formation, including the detrapping energy and capture cross-section of the dominant trap level in polarizing semiconductor radiation detectors. The procedure stems from the laser-induced transient current measurements done at a steady-state and pulsed biasing and at variable temperature. The approach allows us the direct determination of detector parameters from measured data without a complex mathematical treatment. The detrimental effect of surface carrier recombination often hampering the evaluation of detector properties is eliminated. Lifetime worsening caused by the space charge formation is included. The usefulness of the procedure is demonstrated on a CdTe radiation detector.

  11. Assessment of Lymphedema Risk Following Lymph Node Dissection and Radiation Therapy for Primary Breast Cancer

    DTIC Science & Technology

    2004-09-01

    AD_ Award Number: DAMD17-03-1-0622 TITLE: Assessment of Lymphedema Risk Following Lymph Node Dissection and Radiation Therapy for Primary Breast...NUMBERS Assessment of Lymphedema Risk Following Lymph Node DAMDI7-03-1-0622 Dissection and Radiation Therapy for Primary Breast Cancer 6. AUThOR(S...axillary lymph nodes critical for upper extremity drainage predicts the development of lymphedema . In addition to funding this research project, the

  12. Ionizing Radiation and Cancer Risks: What Have We Learned From Epidemiology?

    PubMed Central

    Gilbert, Ethel S.

    2010-01-01

    Purpose Epidemiologic studies of persons exposed to ionizing radiation offer a wealth of information on cancer risks in humans. The Life Span Study cohort of Japanese A-bomb survivors, a large cohort that includes all ages and both sexes with a wide range of well-characterized doses, is the primary resource for estimating carcinogenic risks from low linear energy transfer external exposure. Extensive data on persons exposed for therapeutic or diagnostic medical reasons offer the opportunity to study fractionated exposure, risks at high therapeutic doses, and risks of site-specific cancers in non-Japanese populations. Studies of persons exposed for occupational and environmental reasons allow a direct evaluation of exposure at low doses and dose rates, and also provide information on different types of radiation such as radon and iodine-131. This article summarizes the findings from these studies with emphasis on studies with well-characterized doses. Conclusions Epidemiologic studies provide the necessary data for quantifying cancer risks as a function of dose and for setting radiation protection standards. Leukemia and most solid cancers have been linked with radiation. Most solid cancer data are reasonably well described by linear-dose response functions although there may be a downturn in risks at very high doses. Persons exposed early in life have especially high relative risks for many cancers, and radiation-related risk of solid cancers appears to persist throughout life. PMID:19401906

  13. Radiation risk perception: a discrepancy between the experts and the general population.

    PubMed

    Perko, Tanja

    2014-07-01

    Determining the differences in the perception of risks between experts who are regularly exposed to radiation, and lay people provides important insights into how potential hazards may be effectively communicated to the public. In the present study we examined lay people's (N = 1020) and experts' (N = 332) perception of five different radiological risks: nuclear waste, medical x-rays, natural radiation, an accident at a nuclear installation in general, and the Fukushima accident in particular. In order to link risk perception with risk communication, media reporting about radiation risks is analysed using quantitative and qualitative content analyses. The results showed that experts perceive radiological risks differently from the general public. Experts' perception of medical X-rays and natural radiation is significantly higher than in general population, while for nuclear waste and an accident at a nuclear installation, experts have lower risk perception than the general population. In-depth research is conducted for a group of workers that received an effective dose higher than 0.5 mSv in the year before the study; for this group we identify predictors of risk perception. The results clearly show that mass media don't use the same language as technical experts in addressing radiological risks. The study demonstrates that the discrepancy in risk perception and the communication gap between the experts and the general population presents a big challenge in understanding each other.

  14. Radiation effects.

    PubMed

    Preston, R J

    2012-01-01

    International Commission on Radiological Protection (ICRP) Committee 1 (C1) considers the risk of induction of cancer and heritable disease; the underlying mechanisms of radiation action; and the risks, severity, and mechanisms of induction of tissue reactions (formerly 'deterministic effects'). C1 relies upon the interpretation of current knowledge of radio-epidemiological studies; current information on the underlying mechanisms of diseases and radiation-induced disease; and current radiobiological studies at the whole animal, tissue, cell, and molecular levels. This overview will describe the activities of C1 in the context of the 2007 Recommendations of ICRP. In particular, the conclusions from the most recent C1 Task Group deliberations on radon and lung cancer, and tissue reactions will be discussed. Other activities are described in summary fashion to illustrate those areas that C1 judge to be likely to influence the development of the risk estimates and nominal risk coefficients used for radiation protection purposes.

  15. 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.

  16. Diagnostic Dental Radiation Risk during Pregnancy: Awareness among General Dentists in Tabriz.

    PubMed

    Razi, Tahmineh; Bazvand, Leila; Ghojazadeh, Morteza

    2011-01-01

    Pregnant women often do not receive proper dental care in emergency visits due to a lack of awareness of the effect of radiation doses and the involved risks for the fetus. The aim of the present study was to assess the awareness of general dentists practicing in Tabriz, Iran, of the risks involved during exposure to diagnostic dental radiation in pregnant women. In this descriptive/cross-sectional study, 250 general dentists, who had attended continuing education courses under the supervision of the Faculty of Dentistry, filled out questionnaires on their awareness of radiation risks. Data was analyzed by Spearman's correlation coefficient test. The mean of correct answers was 6.47±1.66, with the least and highest correct answers of 2 and 10, respectively. The highest and the lowest levels of awareness were related to the use of a lead apron (92%) and a long rectangular collimator (3.2%), respectively. There was a statistically significant correlation between the age of practitioners and awareness of radiation risks (P=0.02). However, no statistically significant correlation was observed between job experience (P=0.25) and the number of continuing education courses attended (P=0.16) and awareness of radiation risks. The studied population of dentists does not seem to have the sufficient knowledge regarding the diagnostic dental radiation risk during pregnancy. Further educational courses and pamphlets are recommended for increasing their awareness of this subject.

  17. The Current Status of Graduate Training in Suicide Risk Assessment

    ERIC Educational Resources Information Center

    Liebling-Boccio, Dana E.; Jennings, Heather R.

    2013-01-01

    Directors and coordinators (n = 75) of graduate programs in school psychology approved by the National Association of School Psychologists (NASP) were surveyed regarding their training practices in suicide risk assessment. Respondents viewed the assessment of suicide risk as an important part of graduate instruction, and most believed that…

  18. The Current Status of Graduate Training in Suicide Risk Assessment

    ERIC Educational Resources Information Center

    Liebling-Boccio, Dana E.; Jennings, Heather R.

    2013-01-01

    Directors and coordinators (n = 75) of graduate programs in school psychology approved by the National Association of School Psychologists (NASP) were surveyed regarding their training practices in suicide risk assessment. Respondents viewed the assessment of suicide risk as an important part of graduate instruction, and most believed that…

  19. A review of ground-based heavy-ion radiobiology relevant to space radiation risk assessment: Part II. Cardiovascular and immunological effects

    SciTech Connect

    Blakely, Eleanor A.; Chang, Polly Y.

    2007-02-26

    The future of manned space flight depends on an analysis of the numerous potential risks of travel into deep space. Currently no radiation dose limits have been established for these exploratory missions. To set these standards more information is needed about potential acute and late effects on human physiology from appropriate radiation exposure scenarios, including pertinent radiation types and dose rates. Cancer risks have long been considered the most serious late effect from chronic daily relatively low-dose exposures to the complex space radiation environment. However, other late effects from space radiation exposure scenarios are under study in ground-based accelerator facilities and have revealed some unique particle radiation effects not observed with conventional radiations. A comprehensive review of pertinent literature that considers tissue effects of radiation leading to functional detriments in specific organ systems has recently been published (NCRP National Council on Radiation Protection and Measurements, Information Needed to Make Radiation Protection Recommendations for Space Missions Beyond Low-Earth Orbit, Report 153, Bethesda, MD, 2006). This paper highlights the review of two non-cancer concerns from this report: cardiovascular and immunological effects.

  20. Occupational ionising radiation and risk of basal cell carcinoma in US radiologic technologists (1983-2005).

    PubMed

    Lee, Terrence; Sigurdson, Alice J; Preston, Dale L; Cahoon, Elizabeth K; Freedman, D Michal; Simon, Steven L; Nelson, Kenrad; Matanoski, Genevieve; Kitahara, Cari M; Liu, Jason J; Wang, Timothy; Alexander, Bruce H; Doody, Michele M; Linet, Martha S; Little, Mark P

    2015-12-01

    To determine risk for incident basal cell carcinoma from cumulative low-dose ionising radiation in the US radiologic technologist cohort. We analysed 65,719 Caucasian technologists who were cancer-free at baseline (1983-1989 or 1994-1998) and answered a follow-up questionnaire (2003-2005). Absorbed radiation dose to the skin in mGy for estimated cumulative occupational radiation exposure was reconstructed for each technologist based on badge dose measurements, questionnaire-derived work history and protection practices, and literature information. Radiation-associated risk was assessed using Poisson regression and included adjustment for several demographic, lifestyle, host and sun exposure factors. Cumulative mean absorbed skin dose (to head/neck/arms) was 55.8 mGy (range 0-1735 mGy). For lifetime cumulative dose, we did not observe an excess radiation-related risk (excess relative risk/Gy=-0.01 (95% CI -0.43 to 0.52). However, we observed that basal cell carcinoma risk was increased for radiation dose received before age 30 (excess relative risk/Gy=0.59, 95% CI -0.11 to 1.42) and before 1960 (excess relative risk/Gy=2.92, 95% CI 1.39 to 4.45). Basal cell carcinoma risk was unrelated to low-dose radiation exposure among radiologic technologists. Because of uncertainties in dosimetry and sensitivity to model specifications, both our null results and our findings of excess risk for dose received before age 30 and exposure before 1960 should be interpreted with caution. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. Radiation-Related Risk of Basal Cell Carcinoma: A Report From the Childhood Cancer Survivor Study

    PubMed Central

    2012-01-01

    Background Basal cell carcinoma (BCC) is the most common malignancy in the United States. Ionizing radiation is an established risk factor in certain populations, including cancer survivors. We quantified the association between ionizing radiation dose and the risk of BCC in childhood cancer survivors. Methods Participants in the Childhood Cancer Survivor Study who reported a BCC (case subjects, n = 199) were matched on age and length of follow-up to three study participants who had not developed a BCC (control subjects, n = 597). The radiation-absorbed dose (in Gy) to the BCC location was calculated based on individual radiotherapy records using a custom-designed dosimetry program. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between demographic and treatment factors, therapeutic radiation dose, and surrogate markers of sun sensitivity (skin and hair color) and the risk of BCC. A linear dose–response model was fitted to evaluate the excess odds ratio per Gy of radiation dose. Results Among case subjects, 83% developed BCC between the ages of 20 and 39 years. Radiation therapy, either alone or in combination with chemotherapy, was associated with an increased risk of BCC compared with no chemotherapy or radiation. The odds ratio for subjects who received 35 Gy or more to the skin site vs no radiation therapy was 39.8 (95% CI = 8.6 to 185). Results were consistent with a linear dose–response relationship, with an excess odds ratio per Gy of 1.09 (95% CI = 0.49 to 2.64). No other treatment variables were statistically significantly associated with an increased risk of BCC. Conclusions Radiation doses to the skin of more than 1 Gy are associated with an increased risk of BCC. PMID:22835387

  2. Inner Magnetosphere Modeling at the CCMC: Ring Current, Radiation Belt and Magnetic Field Mapping

    NASA Astrophysics Data System (ADS)

    Rastaetter, L.; Mendoza, A. M.; Chulaki, A.; Kuznetsova, M. M.; Zheng, Y.

    2013-12-01

    Modeling of the inner magnetosphere has entered center stage with the launch of the Van Allen Probes (RBSP) in 2012. The Community Coordinated Modeling Center (CCMC) has drastically improved its offerings of inner magnetosphere models that cover energetic particles in the Earth's ring current and radiation belts. Models added to the CCMC include the stand-alone Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model by M.C. Fok, the Rice Convection Model (RCM) by R. Wolf and S. Sazykin and numerous versions of the Tsyganenko magnetic field model (T89, T96, T01quiet, TS05). These models join the LANL* model by Y. Yu hat was offered for instant run earlier in the year. In addition to these stand-alone models, the Comprehensive Ring Current Model (CRCM) by M.C. Fok and N. Buzulukova joined as a component of the Space Weather Modeling Framework (SWMF) in the magnetosphere model run-on-request category. We present modeling results of the ring current and radiation belt models and demonstrate tracking of satellites such as RBSP. Calculations using the magnetic field models include mappings to the magnetic equator or to minimum-B positions and the determination of foot points in the ionosphere.

  3. Determination of High-Frequency Current Distribution Using EMTP-Based Transmission Line Models with Resulting Radiated Electromagnetic Fields

    SciTech Connect

    Mork, B; Nelson, R; Kirkendall, B; Stenvig, N

    2009-11-30

    Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.

  4. [The determination of the radiation risk during an interplanetary space flight at different periods of solar activity].

    PubMed

    Shafirkin, A V; Venediktova, V P

    1999-01-01

    Based on the own algorithm and Fortran calculation program the authors estimated radiation risk to cosmonauts on an interplanetary mission. They also analyzed the dependence of risk values on mission duration, space vehicle shield thickness, solar phase, and cosmonaut's age. The magnitudes of radiation risk to cosmonauts were compared with the national demographic risk of male lethality over a similar period of time.

  5. Current status of brachytherapy in Korea: a national survey of radiation oncologists.

    PubMed

    Kim, Haeyoung; Kim, Joo Young; Kim, Juree; Park, Won; Kim, Young Seok; Kim, Hak Jae; Kim, Yong Bae

    2016-07-01

    The aim of the present study was to acquire information on brachytherapy resources in Korea through a national survey of radiation oncologists. Between October 2014 and January 2015, a questionnaire on the current status of brachytherapy was distributed to all 86 radiation oncology departments in Korea. The questionnaire was divided into sections querying general information on human resources, brachytherapy equipment, and suggestions for future directions of brachytherapy policy in Korea. The response rate of the survey was 88.3%. The average number of radiation oncologists per center was 2.3. At the time of survey, 28 centers (36.8%) provided brachytherapy to patients. Among the 28 brachytherapy centers, 15 (53.5%) were located in in the capital Seoul and its surrounding metropolitan areas. All brachytherapy centers had a high-dose rate system using (192)Ir (26 centers) or (60)Co (two centers). Among the 26 centers using (192)Ir sources, 11 treated fewer than 40 patients per year. In the two centers using (60)Co sources, the number of patients per year was 16 and 120, respectively. The most frequently cited difficulties in performing brachytherapy were cost related. A total of 21 centers had a plan to sustain the current brachytherapy system, and four centers noted plans to upgrade their brachytherapy system. Two centers stated that they were considering discontinuation of brachytherapy due to cost burdens of radioisotope source replacement. The present study illustrated the current status of brachytherapy in Korea. Financial difficulties were the major barriers to the practice of brachytherapy.

  6. 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

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

    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

  8. Capsaicinoids Modulating Cardiometabolic Syndrome Risk Factors: Current Perspectives

    PubMed Central

    2016-01-01

    Capsaicinoids are bioactive nutrients present within red hot peppers reported to cut ad libitum food intake, to increase energy expenditure (thermogenesis) and lipolysis, and to result in weight loss over time. In addition it has shown more benefits such as improvement in reducing oxidative stress and inflammation, improving vascular health, improving endothelial function, lowering blood pressure, reducing endothelial cytokines, cholesterol lowering effects, reducing blood glucose, improving insulin sensitivity, and reducing inflammatory risk factors. All these beneficial effects together help to modulate cardiometabolic syndrome risk factors. The early identification of cardiometabolic risk factors can help try to prevent obesity, hypertension, diabetes, and cardiovascular disease. PMID:27313880

  9. Ischemic Heart Disease in Workers at Mayak PA: Latency of Incidence Risk after Radiation Exposure

    PubMed Central

    <