Estimation of health risks from radiation exposures

Energy Technology Data Exchange (ETDEWEB)

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.

Epidemiological data and radiation risk estimates

International Nuclear Information System (INIS)

Cardis, E.

2002-01-01

The results of several major epidemiology studies on populations with particular exposure to ionizing radiation should become available during the first years of the 21. century. These studies are expected to provide answers to a number of questions concerning public health and radiation protection. Most of the populations concerned were accidentally exposed to radiation in ex-USSR or elsewhere or in a nuclear industrial context. The results will complete and test information on risk coming from studies among survivors of the Hiroshima and Nagasaki atomic bombs, particularly studies on the effects of low dose exposure and prolonged low-dose exposure, of different types of radiation, and environmental and host-related factors which could modify the risk of radiation-induced effects. These studies are thus important to assess the currently accepted scientific evidence on radiation protection for workers and the general population. In addition, supplementary information on radiation protection could be provided by formal comparisons and analyses combining data from populations with different types of exposure. Finally, in order to provide pertinent information for public health and radiation protection, future epidemiology studies should be targeted and designed to answer specific questions, concerning, for example, the risk for specific populations (children, patients, people with genetic predisposition). An integrated approach, combining epidemiology and studies on the mechanisms of radiation induction should provide particularly pertinent information. (author)

Estimation of radiation cancer risk in CT-KUB

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

Kocher, D.C.

1989-01-01

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

Current estimates of radiation risks and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

The publication of the 1988 report of UNSCEAR represents a major step forward in that there is an international consensus on the estimation of risk from exposure to ionising radiation. The estimates of fatal cancers in the UNSCEAR report are up to 4 times the values in the 1977 review. This paper will describe the reasons for the increase, the remaining uncertainties and the implications for dose limits in occupational and public exposure. (author)

Estimating radiation risk induced by CT screening for Korean population

Science.gov (United States)

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.

A novel tool for user-friendly estimation of natural, diagnostic and professional radiation risk: Radio-Risk software

International Nuclear Information System (INIS)

Carpeggiani, Clara; Paterni, Marco; Caramella, Davide; Vano, Eliseo; Semelka, Richard C.; Picano, Eugenio

2012-01-01

Background: Awareness of radiological risk is low among doctors and patients. An educational/decision tool that considers each patient’ s cumulative lifetime radiation exposure would facilitate provider–patient communication. Aim: The purpose of this work was to develop user-friendly software for simple estimation and communication of radiological risk to patients and doctors as a part of the SUIT-Heart (Stop Useless Imaging Testing in Heart disease) Project of the Tuscany Region. Methods: We developed a novel software program (PC-platform, Windows OS fully downloadable at (http://suit-heart.ifc.cnr.it)) considering reference dose estimates from American Heart Association Radiological Imaging 2009 guidelines and UK Royal College of Radiology 2007 guidelines. Cancer age and gender-weighted risk were derived from Biological Effects of Ionising Radiation VII Committee, 2006. Results: With simple input functions (demographics, age, gender) the user selects from a predetermined menu variables relating to natural (e.g., airplane flights and geo-tracked background exposure), professional (e.g., cath lab workers) and medical (e.g., CT, cardiac scintigraphy, coronary stenting) sources. The program provides a simple numeric (cumulative effective dose in milliSievert, mSv, and equivalent number of chest X-rays) and graphic (cumulative temporal trends of exposure, cancer cases out of 100 exposed persons) display. Conclusions: A simple software program allows straightforward estimation of cumulative dose (in multiples of chest X-rays) and risk (in extra % lifetime cancer risk), with simple numbers quantifying lifetime extra cancer risk. Pictorial display of radiation risk may be valuable for increasing radiological awareness in cardiologists.

A novel tool for user-friendly estimation of natural, diagnostic and professional radiation risk: Radio-Risk software

Energy Technology Data Exchange (ETDEWEB)

Carpeggiani, Clara; Paterni, Marco [CNR, Institute of Clinical Physiology (Italy); Caramella, Davide [Radiology Department, Pisa University, Pisa (Italy); Vano, Eliseo [San Carlos Hospital, Radiology Department, Complutense University, Madrid (Spain); Semelka, Richard C. [University of North Carolina, Chapel Hill, NC (United States); Picano, Eugenio, E-mail: picano@ifc.cnr.it [CNR, Institute of Clinical Physiology (Italy)

2012-11-15

Background: Awareness of radiological risk is low among doctors and patients. An educational/decision tool that considers each patient' s cumulative lifetime radiation exposure would facilitate provider-patient communication. Aim: The purpose of this work was to develop user-friendly software for simple estimation and communication of radiological risk to patients and doctors as a part of the SUIT-Heart (Stop Useless Imaging Testing in Heart disease) Project of the Tuscany Region. Methods: We developed a novel software program (PC-platform, Windows OS fully downloadable at (http://suit-heart.ifc.cnr.it)) considering reference dose estimates from American Heart Association Radiological Imaging 2009 guidelines and UK Royal College of Radiology 2007 guidelines. Cancer age and gender-weighted risk were derived from Biological Effects of Ionising Radiation VII Committee, 2006. Results: With simple input functions (demographics, age, gender) the user selects from a predetermined menu variables relating to natural (e.g., airplane flights and geo-tracked background exposure), professional (e.g., cath lab workers) and medical (e.g., CT, cardiac scintigraphy, coronary stenting) sources. The program provides a simple numeric (cumulative effective dose in milliSievert, mSv, and equivalent number of chest X-rays) and graphic (cumulative temporal trends of exposure, cancer cases out of 100 exposed persons) display. Conclusions: A simple software program allows straightforward estimation of cumulative dose (in multiples of chest X-rays) and risk (in extra % lifetime cancer risk), with simple numbers quantifying lifetime extra cancer risk. Pictorial display of radiation risk may be valuable for increasing radiological awareness in cardiologists.

Use of BEIR V and UNSCEAR 1988 in radiation risk assessment: Lifetime total cancer mortality risk estimates at low doses and low dose rates for low-LET radiation

International Nuclear Information System (INIS)

1992-12-01

In November 1986, the Department of Defense (DoD) asked the Committee on Interagency Radiation Research and Policy Coordination (CIRRPC) to develop a coordinated Federal position on risk assessment for low levels of ionizing radiation. Since Federal risk assessment activities are based primarily on the scientific data and analyses in authoritative review documents prepared by groups like the National Academy of Sciences' Committee on the Biological Effects of Ionizing Radiation (BEIR), the National Council on Radiation Protection and Measurements (NCRP) and the United Nations' Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), DoD proposed that the CIRRPC Science Panel undertake the task of providing coordinated interagency positions on the use of information in the reports of such groups. The practice has been for individual Federal agencies to interpret and decide independently how to use the information provided in such reports. As a result of its deliberations, the Subpanel recommends two nominal risk estimates for lifetime total cancer mortality following whole-body exposure to low levels of low-LET ionizing radiation, one for the general population and one for the working-age population (see Section II). The recommended risk estimates reflect the general agreement of information in BEIR V and UNSCEAR 1988 for total cancer mortality. The Subpanel's risk estimates and associated statements are intended to meet the needs of the Federal agencies for: (a) values that are current; (b) values that are relevant to the low-dose and low dose-rate ionizing radiation exposures principally encountered in carrying out Federal responsibilities; (c) a statement of the change in the estimates of lifetime total cancer mortality relative to estimates in previous authoritative review documents; and (d) a practical statement on the scientific uncertainty associated with applying the lifetime total cancer mortality values at very low doses

The impact of advances in human molecular biology on radiation genetic risk estimation in man

International Nuclear Information System (INIS)

Sankaranarayanan, K.

1996-01-01

This paper provides an overview of the conceptual framework, the data base, methods and assumptions used thus far to assess the genetic risks of exposure of human populations to ionising radiation. These are then re-examined in the contemporary context of the rapidly expanding knowledge of the molecular biology of human mendelian diseases. This re-examination reveals that (i) many of the assumptions used thus far in radiation genetic risk estimation may not be fully valid and (ii) the current genetic risk estimates are probably conservative, but provide an adequate margin of safety for radiological protection. The view is expressed that further advances in the field of genetic risk estimation will be largely driven by advances in the molecular biology of human genetic diseases. (author). 37 refs., 5 tabs

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

Science.gov (United States)

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

Estimating radiation-induced cancer risk using MVK two-stage model for carcinogenesis

International Nuclear Information System (INIS)

Kai, M.; Kusama, T.; Aoki, Y.

1993-01-01

Based on the carcinogenesis model as proposed by Moolgavkar et al., time-dependent relative risk models were derived for projecting the time variation in excess relative risk. If it is assumed that each process is described by time-independent linear dose-response relationship, the time variation in excess relative risk is influenced by the parameter related with the promotion process. The risk model based carcinogenesis theory would play a marked role in estimating radiation-induced cancer risk in constructing a projection model or transfer model

Estimated risk of radiation-induced cancer from paediatric chest CT: two-year cohort study

Energy Technology Data Exchange (ETDEWEB)

Niemann, Tilo [Cantonal Hospital Baden, Department of Radiology, Baden (Switzerland); University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Colas, Lucie; Santangelo, Teresa; Faivre, Jean Baptiste; Remy, Jacques; Remy-Jardin, Martine [University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Roser, Hans W.; Bremerich, Jens [University of Basel Hospital, Clinic of Radiology and Nuclear Medicine, Medical Physics, Basel (Switzerland)

2015-03-01

The increasing absolute number of paediatric CT scans raises concern about the safety and efficacy and the effects of consecutive diagnostic ionising radiation. To demonstrate a method to evaluate the lifetime attributable risk of cancer incidence/mortality due to a single low-dose helical chest CT in a two-year patient cohort. A two-year cohort of 522 paediatric helical chest CT scans acquired using a dedicated low-dose protocol were analysed retrospectively. Patient-specific estimations of radiation doses were modelled using three different mathematical phantoms. Per-organ attributable cancer risk was then estimated using epidemiological models. Additional comparison was provided for naturally occurring risks. Total lifetime attributable risk of cancer incidence remains low for all age and sex categories, being highest in female neonates (0.34%). Summation of all cancer sites analysed raised the relative lifetime attributable risk of organ cancer incidence up to 3.6% in female neonates and 2.1% in male neonates. Using dedicated scan protocols, total lifetime attributable risk of cancer incidence and mortality for chest CT is estimated low for paediatric chest CT, being highest for female neonates. (orig.)

Cancer risk as a radiation detriment

International Nuclear Information System (INIS)

Servomaa, A.; Komppa, T.; Servomaa, K.

1992-11-01

Potential radiation detriment means a risk of cancer or other somatic disease, genetic damage of fetal injury. Quantative information about the relation between a radiation dose and cancer risk is needed to enable decision-making in radiation protection. However, assessment of cancer risk by means of the radiation dose is controversial, as epidemiological and biological information about factors affecting the origin of cancers show that risk assessment is imprecise when the radiation dose is used as the only factor. Focusing on radiation risk estimates for breast cancer, lung cancer and leukemia, the report is based on the models given in the Beir V report, on sources of radiation exposure and the uncertainty of risk estimates. Risk estimates are assessed using the relative risk model and the cancer mortality rates in Finland. Cancer incidence and mortality rates for men and women are shown in graphs as a function of age and time. Relative risks are shown as a function of time after exposure and lifetime risks as a function of age at exposure. Uncertainty factors affecting the radiation risk are examined from the point of view of epidemiology and molecular biology. (orig.)

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

International Nuclear Information System (INIS)

Russell, W.L.

1980-01-01

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

Risk estimation of radiation exposure in early pregnancy

International Nuclear Information System (INIS)

Neumeister, K.; Waesser, S.

1977-01-01

The biomedical effects of radiation exposure (occupational, by X-ray diagnosis or examinations in nuclear medicine) to low doses on early pregnancy have been subject of a research work dealing with the dose level which, in case of exceeding, may lead to somatic damage (1.5 to 10 rem), and with the type of radiation injuries (malformations, functional disorder, cancer induction, increase in morbidity rate, genetic damage). A pilot study was the basis for the programme which will record such cases from all over the GDR. Within the scope of the health centre at the National Board of Nuclear Safety and Radiation Protection of the GDR, medical opinion on the interruption or preservation of pregnancy at its early stage, after exposure, was delivered in more than 50 cases. Exposure of the foetus was exactly determined. These children were re-investigated at the age of 1 to 3 years by applying pediatric and genetic examinations. The latter were based on clinical and biochemical methods as well as chromosome analyses. From these results, the risk of exposure in early pregnancy is estimated and adequate dose limits are suggested. In case these limits are exceeded, an interruption should be advised

Genetic risks from radiation

International Nuclear Information System (INIS)

Selby, P.B.

Two widely-recognized committees, UNSCEAR and BEIR, have reevaluated their estimates of genetic risks from radiation. Their estimates for gene mutations are based on two different approaches, one being the doubling-dose approach and the other being a new direct approach based on an empirical determination of the amount of dominant induced damage in the skeletons of mice in the first generation following irradiation. The estimates made by these committees are in reasonably good agreement and suggest that the genetic risks from present exposures resultng from nuclear power production are small. There is room for much improvement in the reliability of the risk estimates. The relatively new approach of measuring the amount of induced damage to the mouse skeleton shows great promise of improving knowledge about how changes in the mutation frequency affect the incidence of genetic disorders. Such findings may have considerable influence on genetic risk estimates for radiation and on the development of risk estimates for other less-well-understood environmental mutagens. (author)

Competing risk theory and radiation risk assessment

International Nuclear Information System (INIS)

Groer, P.G.

1980-01-01

New statistical procedures are applied to estimate cumulative distribution functions (c.d.f.), force of mortality, and latent period for radiation-induced malignancies. It is demonstrated that correction for competing risks influences the shape of dose response curves, estimates of the latent period, and of the risk from ionizing radiations. The equivalence of the following concepts is demonstrated: force of mortality, hazard rate, and age or time specific incidence. This equivalence makes it possible to use procedures from reliability analysis and demography for radiation risk assessment. Two methods used by reliability analysts - hazard plotting and total time on test plots - are discussed in some detail and applied to characterize the hazard rate in radiation carcinogenesis. C.d.f.'s with increasing, decreasing, or constant hazard rate have different shapes and are shown to yield different dose-response curves for continuous irradiation. Absolute risk is shown to be a sound estimator only if the force of mortality is constant for the exposed and the control group. Dose-response relationships that use the absolute risk as a measure for the effect turn out to be special cases of dose-response relationships that measure the effect with cumulative incidence. (H.K.)

Current features on risk perception and risk communication of radiation

International Nuclear Information System (INIS)

Kusama, Tomoko

1997-01-01

Health effects and risks of radiation and radionuclides are being misunderstood by many members of general public. Many peoples have fear and anxieties for radiation. So far, the health effects from radiation at low dose and low dose rate have not been cleared on biological aspects. Then, we have quantitatively estimated health risks of low-dose radiation on the basis of linear dose response relationship without threshold from the viewpoints of radiation protection by using both epidemiological data, such as atomic bomb survivors, and some models and assumptions. It is important for researchers and relevant persons in radiation protection to understand the process of risk estimation of radiation and to communicate an exact knowledge of radiation risks of the public members. (author)

Theoretical epidemiology applied to health physics: estimation of the risk of radiation-induced breast cancer

International Nuclear Information System (INIS)

Sutherland, J.V.

1983-01-01

Indirect estimation of low-dose radiation hazards is possible using the multihit model of carcinogenesis. This model is based on cancer incidence data collected over many decades on tens of millions of people. Available data on human radiation effects can be introduced into the modeling process without the requirement that these data precisely define the model to be used. This reduction in the information demanded from the limited data on human radiation effects allows a more rational approach to estimation of low-dose radiation hazards and helps to focus attention on research directed towards understanding the process of carcinogenesis, rather than on repeating human or animal experiments that cannot provide sufficient data to resolve the low-dose estimation problem. Assessment of the risk of radiation-induced breast cancer provides an excellent example of the utility of multihit modeling procedures

Uncertainties in fatal cancer risk estimates used in radiation protection

International Nuclear Information System (INIS)

Kai, Michiaki

1999-01-01

Although ICRP and NCRP had not described the details of uncertainties in cancer risk estimates in radiation protection, NCRP, in 1997, firstly reported the results of uncertainty analysis (NCRP No.126) and which is summarized in this paper. The NCRP report pointed out that there are following five factors which uncertainty possessing: uncertainty in epidemiological studies, in dose assessment, in transforming the estimates to risk assessment, in risk prediction and in extrapolation to the low dose/dose rate. These individual factors were analyzed statistically to obtain the relationship between the probability of cancer death in the US population and life time risk coefficient (% per Sv), which showed that, for the latter, the mean value was 3.99 x 10 -2 /Sv, median, 3.38 x 10 -2 /Sv, GSD (geometrical standard deviation), 1.83 x 10 -2 /Sv and 95% confidential limit, 1.2-8.84 x 10 -2 /Sv. The mean value was smaller than that of ICRP recommendation (5 x 10 -2 /Sv), indicating that the value has the uncertainty factor of 2.5-3. Moreover, the most important factor was shown to be the uncertainty in DDREF (dose/dose rate reduction factor). (K.H.)

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

Science.gov (United States)

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

2011-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

We can do better than effective dose for estimating or comparing low-dose radiation risks

International Nuclear Information System (INIS)

Brenner, D.J.

2012-01-01

The effective dose concept was designed to compare the generic risks of exposure to different radiation fields. More commonly these days, it is used to estimate or compare radiation-induced cancer risks. For various reasons, effective dose represents flawed science: for instance, the tissue-specific weighting factors used to calculate effective dose are a subjective mix of different endpoints; and the marked and differing age and gender dependencies for different health detriment endpoints are not taken into account. This paper suggests that effective dose could be replaced with a new quantity, ‘effective risk’, which, like effective dose, is a weighted sum of equivalent doses to different tissues. Unlike effective dose, where the tissue-dependent weighting factors are a set of generic, subjective committee-defined numbers, the weighting factors for effective risk are simply evaluated tissue-specific lifetime cancer risks per unit equivalent dose. Effective risk, which has the potential to be age and gender specific if desired, would perform the same comparative role as effective dose, be just as easy to estimate, be less prone to misuse, be more directly understandable, and would be based on solid science. An added major advantage is that it gives the users some feel for the actual numerical values of the radiation risks they are trying to control.

Some statistical considerations related to the estimation of cancer risk following exposure to ionizing radiation

International Nuclear Information System (INIS)

Land, C.E.; Pierce, D.A.

1983-01-01

Statistical theory and methodology provide the logical structure for scientific inference about the cancer risk associated with exposure to ionizing radiation. Although much is known about radiation carcinogenesis, the risk associated with low-level exposures is difficult to assess because it is too small to measure directly. Estimation must therefore depend upon mathematical models which relate observed risks at high exposure levels to risks at lower exposure levels. Extrapolated risk estimates obtained using such models are heavily dependent upon assumptions about the shape of the dose-response relationship, the temporal distribution of risk following exposure, and variation of risk according to variables such as age at exposure, sex, and underlying population cancer rates. Expanded statistical models, which make explicit certain assumed relationships between different data sets, can be used to strengthen inferences by incorporating relevant information from diverse sources. They also allow the uncertainties inherent in information from related data sets to be expressed in estimates which partially depend upon that information. To the extent that informed opinion is based upon a valid assessment of scientific data, the larger context of decision theory, which includes statistical theory, provides a logical framework for the incorporation into public policy decisions of the informational content of expert opinion

Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

Directory of Open Access Journals (Sweden)

Adeleye Bamise

2017-12-01

Full Text Available The preference for computed tomography (CT for the clinical assessment of pulmonary tuberculosis (PTB infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05 between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05 and female patients (r2 = 0.989, P < 0.05. The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively. These variations provide an indication that the use of a scanner optimizing protocol is imperative.

Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

Science.gov (United States)

Adeleye, Bamise; Chetty, Naven

2017-12-01

The preference for computed tomography (CT) for the clinical assessment of pulmonary tuberculosis (PTB) infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05) between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05) and female patients (r2 = 0.989, P < 0.05). The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively). These variations provide an indication that the use of a scanner optimizing protocol is imperative.

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

Science.gov (United States)

Chappell, Lori J.; Cucinotta, Francis A.

2011-01-01

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

Dose-response relationships and risk estimates for the induction of cancer due to low doses of low-LET radiation

International Nuclear Information System (INIS)

Elaguppillai, V.

1981-01-01

Risk estimates for radiation-induced cancer at low doses can be obtained only by extrapolation from the known effects at high doses and high dose rates, using a suitable dose-response model. The applicability of three different models, linear, sublinear and supralinear, are discussed in this paper. Several experimental studies tend to favour a sublinear dose-response model (linear-quadratic model) for low-LET radiation. However, human epidemiological studies do not exclude any of the dose-response relationships. The risk estimates based on linear and linear quadratic dose-response models are compared and it is concluded that, for low-LET radiation, the linear dose-response model would probably over-estimate the actual risk of cancer by a factor of two or more. (author)

Quantifying Cancer Risk from Radiation.

Science.gov (United States)

Keil, Alexander P; Richardson, David B

2017-12-06

Complex statistical models fitted to data from studies of atomic bomb survivors are used to estimate the human health effects of ionizing radiation exposures. We describe and illustrate an approach to estimate population risks from ionizing radiation exposure that relaxes many assumptions about radiation-related mortality. The approach draws on developments in methods for causal inference. The results offer a different way to quantify radiation's effects and show that conventional estimates of the population burden of excess cancer at high radiation doses are driven strongly by projecting outside the range of current data. Summary results obtained using the proposed approach are similar in magnitude to those obtained using conventional methods, although estimates of radiation-related excess cancers differ for many age, sex, and dose groups. At low doses relevant to typical exposures, the strength of evidence in data is surprisingly weak. Statements regarding human health effects at low doses rely strongly on the use of modeling assumptions. © 2017 Society for Risk Analysis.

Assessment of risk from radiation sources

International Nuclear Information System (INIS)

Subbaratnam, T.; Madhvanath, U.; Somasundaram, S.

1976-01-01

Assessment of risk from exposure to ionizing radiations from man-made radiation sources and nuclear installations has to be viewed from three aspects, namely, dose-effect relationship (genetic and somatic) for humans, calculation of doses or dose-commitments to population groups, assessment of risk to radiation workers and the population at large from the current levels of exposure from nuclear industry and comparison of risk estimates with other industries in a modern society. These aspects are discussed in brief. On the basis of available data, it is shown that estimated incidence of genetic diseases and cancers due to exposure of population to radiation from nuclear industry is negligible in comparison with their natural incidence, and radiation risks to the workers in nuclear industry are much lower than the risks in other occupations. (M.G.B.)

The impact on radiation risk estimates of effect modifiers and confounders

International Nuclear Information System (INIS)

Sharp, G.B.; Cologne, J.B.; Pierce, D.A.; Tokuoka, S.

2003-01-01

We have conducted studies of the joint effects of radiation with other risk factors for liver, lung, and breast cancer in the cohort of Japanese survivors of the 1945 atomic bombings. Based on follow-up of 45,113 subjects from 1958 through 1994, of whom 592 developed lung cancer, we found the effects of smoking and radiation to be significantly non-multiplicative and consistent with additivity. Adjustment for smoking reduced the female:male ratio of radiation risk estimates for lung cancer in this cohort from 5.8 to 1.6, a ratio more similar to that for all solid cancers. We conducted cross sectional and case control studies within the A-bomb survivor cohort to assess the joint effects of radiation with hepatitis B virus (HBV) and C virus (HCV) infections on the etiology of liver cirrhosis and hepatocellular carcinoma (HCC). Our study of 268 pathologist-confirmed cirrhosis cases and 843 subjects without cirrhosis, found no relationship between A-bomb radiation and cirrhosis after adjustment for viral hepatitis. In terms of HCC, our study of 238 pathologist-confirmed cases and 894 controls showed super-multiplicative interaction between radiation and HCV infections. Our results suggest that while chronic radiation exposure acts as a complete carcinogen for HCC, acute irradiation may act in concert with an agent such as HCV that is associated with liver cell proliferation. Studies in progress of the joint effects of radiation with insulin-like growth factor 1 (IGF-1) and IGF Binding Protein 3 (IGFBP-3), and total estradiol on the etiology of breast cancer, a particularly radiogenic tumor, will also be discussed

Estimation of baseline lifetime risk of developed cancer related to radiation exposure in China

International Nuclear Information System (INIS)

Li Xiaoliang; Niu Haowei; Sun Quanfu; Ma Weidong

2011-01-01

Objective: To introduce the general international method for estimation of lifetime risk of developed cancer, and to estimate the lifetime risk baseline values of several kinds of cancers related to radiation exposures in China. Methods: The risk estimation was based on the data from Chinese Cancer Registry Annual Report (2010) and China Population and Employment Statistics Yearbook (2009), and made according to the method previously published by National Cancer Institute (NCI) in USA. Results: The lifetime risk of all cancer in China in 2007 was estimated to be 27.77%, that of lung cancer 5.96%, that of breast cancer for female 3.34%, that of all leukemia 0.14%, that of thyroid cancer 0.37%. The lifetime risks of all cancer were estimated to be 32.74% for males and 24.73% for females, and that was 36.47% for urban residents and 26.79% for rural people. Conclusions: The lifetime risk of all cancer for males in 2007 was about 1.25 times as much as that for females. The value of all cancer for urban residents was about 1.35 times as much as that for rural residents. The lifetime risk of developed cancers in 2007 in China is lower than that in the developed countries,such as Japan. (authors)

Probabilistic methodology for estimating radiation-induced cancer risk

International Nuclear Information System (INIS)

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

Radiation risks in pregnancy

International Nuclear Information System (INIS)

Mossman, K.L.; Hill, L.T.

1982-01-01

A major contraindication of radiodiagnostic procedures is pregnancy. Approximately 1% of all pregnant women are given abdominal x-rays during the first trimester of pregnancy. Evaluation of radiation exposure should involve consideration of the types of examinations performed and when performed, as well as radiation dose and risk estimation. This information is then weighed against other possible risks of the pregnancy as well as personal factors. In the authors' experiences, radiation exposures usually result in doses to the embryo of less than 5 cGy (rad); the resulting radiation risks are usually small compared with other risks of pregnancy. Procedures to minimize diagnostic x-ray exposure of the fetus are also discussed

An estimation of the risk for the use of stable iodine in radiation protection in an iodine deficient population

International Nuclear Information System (INIS)

Gloebel, B.; Gloebel, H.; Muth, H.; Andres, C.

1982-01-01

The radiation risk of the thyroid is estimated by use of data from the literature and our investigations. Comparing these results with the statistical incidence of radiation evoked diseases the risk of a patient to develop thyroid carcinoma receiving 50 μCi 131 I for thyroid diagnostics is about tenfold compared to the spontaneous risk with a twofold risk to develop hypothyroidism. Using sup(99m)Tc or 123 I these risks are minimized to a small percentage. For technicians in the RIA lab or during labelling of proteins the thyroid's radiation risk can be diminished by ingestion of inactive iodine, however, this procedure includes new risks of iodine side-effects. Comparing the pharmacological risks of iodine intake and the radiation risk it seems to be useful to suggest iodine prophylaxis when the expected radiation dose exceeds 10 rad in the thyroid. (author)

Hypofractionation does not increase radiation pneumonitis risk with modern conformal radiation delivery techniques

DEFF Research Database (Denmark)

Vogelius, Ivan R; Westerly, David C; Cannon, George M

2010-01-01

To study the interaction between radiation dose distribution and hypofractionated radiotherapy with respect to the risk of radiation pneumonitis (RP) estimated from normal tissue complication probability (NTCP) models.......To study the interaction between radiation dose distribution and hypofractionated radiotherapy with respect to the risk of radiation pneumonitis (RP) estimated from normal tissue complication probability (NTCP) models....

Risks for radiation workers

International Nuclear Information System (INIS)

Rotblat, J.

1978-01-01

The following topics are discussed: recommendations of the International Commission on Radiological Protection; methods for determining dose limits to workers; use of data from survivors of Hiroshima and Nagasaki for estimating risk factors; use of data from survivors of nuclear explosions in Marshall Islands, uranium miners, and patients exposed to diagnostic and therapeutic radiation; risk factors for radioinduced malignancies; evidence that risk factors for persons exposed to partial-body radiation and Japanese survivors are too low; greater resistance of A-bomb survivors to radiation; and radiation doses received by U.K. medical workers and by U.K. fuel reprocessing workers. It is suggested that the dose limit for radiation workers should be reduced by a factor of 5

Health risk assessment of exposure to ionizing radiation

International Nuclear Information System (INIS)

Ogata, Hiromitsu

2011-01-01

Risk assessment is an essential process for evaluating the human health effects of exposure to ionizing radiation and for determining acceptable levels of exposure. There are two major components of radiation risk assessment: a measure of exposure level and a measure of disease occurrence. For quantitative estimation of health risks, it is important to evaluate the association between exposure and disease occurrence using epidemiological or experimental data. In these approaches, statistical risk models are used particularly for estimating cancer risks related to exposure to low levels of radiation. This paper presents a summary of basic models and methods of risk assessment for studying exposure-risk relationships. Moreover, quantitative risk estimates are subject to several sources of uncertainty due to inherent limitations in risk assessment studies. This paper also discusses the limitations of radiation risk assessment. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Mazonakis, Michalis; Berris, Theoharris; Damilakis, John [Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, 71003 Iraklion, Crete (Greece); Lyraraki, Efrossyni [Department of Radiotherapy and Oncology, University Hospital of Iraklion, 71110 Iraklion, Crete (Greece)

2013-10-15

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

To manage the ionizing radiations risks

International Nuclear Information System (INIS)

Metivier, H.; Romerio, F.

2000-01-01

Mister Romerio's work tackles the problem of controversy revealed by the experts in the field of estimation and management of ionizing radiations risks. The author describes the three paradigms at the base of the debate: the relationship without threshold (typified by the ICRP and its adepts), these ones that think that low doses risks are overestimated ( Medicine Academia for example) or that ones that believe that dose limits are too severe and induce unwarranted costs; then that ones that think that these risks are under-estimated and limits should be more reduced, even stop these practices that lead to public exposure to ionizing radiations. The author details the uncertainties about the risk estimations, refreshes the knowledge in radiation protection with the explanations of the different paradigms. At the end a table summarize the positions of the three paradigms

Radiobiological risk estimates of adverse events and secondary cancer for proton and photon radiation therapy of pediatric medulloblastoma

Energy Technology Data Exchange (ETDEWEB)

Brodin, N. Patrik (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark); Niels Bohr Inst., Faculty of Sciences, Univ. of Copenhagen (Denmark)), e-mail: brodin.patrik@gmail.com; Munck af Rosenschoeld, Per; Aznar, Marianne C.; Vogelius, Ivan R. (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark)); Kiil-Berthelsen, Anne (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark); Dept. of Clinical Physiology and Nuclear Medicine, Centre of Diagnostic Investigations, Rigshospitalet, Univ. of Copenhagen (Denmark)); Nilsson, Per; Bjoerk-Eriksson, Thomas (Dept. of Oncology, Skaane Univ. Hospital and Lund Univ., Lund (Sweden)); Lannering, Birgitta (Dept. of Paediatric Oncology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden))

2011-08-15

Introduction. The aim of this model study was to estimate and compare the risk of radiation-induced adverse late effects in pediatric patients with medulloblastoma (MB) treated with either three-dimensional conformal radiotherapy (3D CRT), inversely-optimized arc therapy (RapidArc (RA)) or spot-scanned intensity-modulated proton therapy (IMPT). The aim was also to find dose-volume toxicity parameters relevant to children undergoing RT to be used in the inverse planning of RA and IMPT, and to use in the risk estimations. Material and methods. Treatment plans were created for all three techniques on 10 pediatric patients that have been treated with craniospinal irradiation (CSI) at our institution in 2007-2009. Plans were generated for two prescription CSI doses, 23.4 Gy and 36 Gy. Risk estimates were based on childhood cancer survivor data when available and secondary cancer (SC) risks were estimated as a function of age at exposure and attained age according to the organ-equivalent dose (OED) concept. Results. Estimates of SC risk was higher for the RA plans and differentiable from the estimates for 3D CRT at attained ages above 40 years. The risk of developing heart failure, hearing loss, hypothyroidism and xerostomia was highest for the 3D CRT plans. The risks of all adverse effects were estimated as lowest for the IMPT plans, even when including secondary neutron (SN) irradiation with high values of the neutron radiation weighting factors (WR{sub neutron}). Conclusions. When comparing RA and 3D CRT treatment for pediatric MB it is a matter of comparing higher SC risk against higher risks of non-cancer adverse events. Considering time until onset of the different complications is necessary to fully assess patient benefit in such a comparison. The IMPT plans, including SN dose contribution, compared favorably to the photon techniques in terms of all radiobiological risk estimates

Radiobiological risk estimates of adverse events and secondary cancer for proton and photon radiation therapy of pediatric medulloblastoma

International Nuclear Information System (INIS)

Brodin, N. Patrik; Munck af Rosenschoeld, Per; Aznar, Marianne C.; Vogelius, Ivan R.; Kiil-Berthelsen, Anne; Nilsson, Per; Bjoerk-Eriksson, Thomas; Lannering, Birgitta

2011-01-01

Introduction. The aim of this model study was to estimate and compare the risk of radiation-induced adverse late effects in pediatric patients with medulloblastoma (MB) treated with either three-dimensional conformal radiotherapy (3D CRT), inversely-optimized arc therapy (RapidArc (RA)) or spot-scanned intensity-modulated proton therapy (IMPT). The aim was also to find dose-volume toxicity parameters relevant to children undergoing RT to be used in the inverse planning of RA and IMPT, and to use in the risk estimations. Material and methods. Treatment plans were created for all three techniques on 10 pediatric patients that have been treated with craniospinal irradiation (CSI) at our institution in 2007-2009. Plans were generated for two prescription CSI doses, 23.4 Gy and 36 Gy. Risk estimates were based on childhood cancer survivor data when available and secondary cancer (SC) risks were estimated as a function of age at exposure and attained age according to the organ-equivalent dose (OED) concept. Results. Estimates of SC risk was higher for the RA plans and differentiable from the estimates for 3D CRT at attained ages above 40 years. The risk of developing heart failure, hearing loss, hypothyroidism and xerostomia was highest for the 3D CRT plans. The risks of all adverse effects were estimated as lowest for the IMPT plans, even when including secondary neutron (SN) irradiation with high values of the neutron radiation weighting factors (WR neutron ). Conclusions. When comparing RA and 3D CRT treatment for pediatric MB it is a matter of comparing higher SC risk against higher risks of non-cancer adverse events. Considering time until onset of the different complications is necessary to fully assess patient benefit in such a comparison. The IMPT plans, including SN dose contribution, compared favorably to the photon techniques in terms of all radiobiological risk estimates

Estimation, assessment and management of risks

International Nuclear Information System (INIS)

Reinoehl-Kompa, S.

2005-01-01

After the introductory lectures the closed conference divided into sessions on the estimation, assessment and management of risks. This review article summarises some of the central issues which were addressed in the discussions held during the closed conference and which may be of significance for the future work of the ''Radiation Risk'' Committee within the Radiation Protection Commission. Fundamental difficulties still persist in the implementation of risk quantities within the concepts of radiation protection (lectures by Breckow and Kiefer). Some of these difficulties have to do with the definition of dose quantities, in particular with the one most central to radiation protection, the effective dose. In the field of sparsely ionizing radiation attention was focused on two main topics, namely the risk of acquiring thyroid cancer in association with the Chernobyl desaster and analyses of new mortality data on the survivors of the nuclear bomb attacks on Hiroshima and Nagasaki. In the area of lung cancer risk from radon exposure, attention was focused on indoor exposure and the cohort study on bismuth miners. The body of knowledge that has accumulated on the risk of acquiring cancer through UV radiation takes a special position within the wider field of risks associated with nonionizing radiation, since much has already been achieved towards identifying the action mechanisms involved here. Since skin cancer shows the highest increments in incidence of all types of cancer, estimating the risk of acquiring skin cancer through UV radiation will be an important issue in future. One of the tasks of risk management is to translate the results of risk assessment into action. One task of particular importance in this regard is ''risk communication'', the problems surrounding which were illuminated from different perspectives in various contributions

The risk philosophy of radiation protection

International Nuclear Information System (INIS)

Lindell, B.

1996-01-01

The processes of risk assessment and risk evaluation are described. The assumptions behind current radiation risk assessments, which are focused on the probability of attributable death from radiation-induced cancer, are reviewed. These assessments involve projection models to take account of future cancer death in irradiated populations, the transfer of risk estimates between populations and the assumptions necessary to derive risk assessments for low radiation doses from actual observations at high doses. The paper ends with a presentation of the basic radiation protection recommendations of the International Commission on Radiological Protection (ICRP) in the context of a risk philosophy. (author)

Possibility of use of plat test systems for estimation of degree risk at radiation influence

International Nuclear Information System (INIS)

Gogebashvili, M.E.; Ivanishvili, N.I.

2010-01-01

Full text : Now one of the major problems of radiobiology is studying of degree risks at influence of small doses of an ionizing radiation. It is known, that not tumoral forms of the remote pathology are not stochastic, threshold, reactions of an organism to beam influence, frequency and weight depend on a dose, while carcinogenic and genetic effects (stochastic reactions) - frequency raises with dose increase. Last years the general hypothesis for definition of the raised risk in the irradiated populations, based on the theoretical analysis of extensive researches of various biological objects and epidemiological data, assumes existence of difficult parities between a dose of an irradiation and frequency of investigated effect. In this aspect the special importance is got by biological models with which help reception of quantitative parameters of influence of modifying factors for creation of more exact systems of monitoring of the remote radiobiological effects is possible. One of such systems is reciprocal grows reaction of stamen threads of plant tradescantia. At the heart of action of the given biomodel that growth tradescantia threads occurs from one initial cell is, and level of its radiating damage is shown in number of the subsequent cellular generation during the postradiating period. For an estimation of adequacy of the given model we had been chose two kinds tradescantia - Tradescantia virginiana L. and Tradescantia rosea Vent. It is notes, that at identical quantity of chromosomes their volume interface nucleus composable at Tradescantia virginiana L. 63.7 μ 3 , and at T.rosea Vent. - 38.5 μ 3 . Thus at interpretation of data it was possible to estimate them with the target theory. In work two basic criteria of an estimation of radiating damage - quantity of viable pollen threads and quantity of viable cells in each of threads have been used. The received results have shown strict correlation of reciprocal postradiating effects between used variants

Radiation risk and radiation protection concepts

International Nuclear Information System (INIS)

Doerschel, B.

1989-01-01

The revised dosimetry for the survivors of Hiroshima and Nagasaki implies an increased risk from low LET radiation compared with that currently used. During its meeting in 1987 the ICRP stated that the new data at present do not require any change in the dose limits. However, two other factors can cause larger changes in the present risk estimates. Firstly, for some types of cancer the relative risk model seems to describe the observed data better than the absolute risk model currently used by the ICRP. Secondly, the shape of the dose-response relationship considerably influences the derived risks. In the present paper the factor causing a substantial increase in radiation risk are analyzed. Conclusions are drawn in how far a change in the currently recommended dose limits seems to be necessary. (author)

A review of radiation risk estimates

International Nuclear Information System (INIS)

1991-06-01

Three authoritative reports (UNSCEAR-1988, BEIR-V-1990, and ICRP-1990 Recommendations) on risk estimates have been reviewed and compared to previous risk estimates published by the same organizations. The ICRP now uses the term 'probability' in place of the term 'risk'. For fatal cancers, the new ICRP probability estimates are 5.0 x 10 -2 Sv -1 for a population of all ages and 4.0 x 10 -2 Sv -1 for a population of working age. For serious hereditary effects summarized over all generations, the ICRP probability coefficients are 1.0 x 10 -2 Sv -1 for a population of all ages and 0.6 x 10 -2 Sv -1 for a population of working age. For prenatal irradiation, at 8 - 15 weeks after conception, there may be a decrease of 30 I.Q. points per Sv and a risk of cancer which may lie in the range of 2 to 10 x 10 -2 Sv -1 . Based mainly on the new probability estimates the ICRP recommends a limit on effective dose of 20 mSv per year, averaged over 5 years (100 mSv in 5 years) with the further provision that the effective dose should not exceed 50 mSv in any single year. For public exposure the ICRP recommends an annual limit on effective dose of 1 mSv. However, in special circumstances, a higher value of effective dose could be allowed in a single year provided that the average over 5 five years does not exceed 1 mSv per year. Once pregnancy has been declared, the conceptus should be protected by applying a supplementary equivalent dose limit to the surface of the woman's abdomen of 2 mSv for the remainder of the pregnancy and by limiting intakes of radionuclides to about 1/20 of the annual limit on intake. A brief survey of epidemiological studies of workers and the risks from radon and thoron progeny is also included. (110 refs, 29 tabs., 10 figs.)

Risk estimates for exposure to alpha emitters

International Nuclear Information System (INIS)

1982-07-01

The primary scope of this report is to evaluate the risk of lung cancer from occupational exposure to short-lived daughters of radon and thoron. The Subcommittee on Risk Estimates considers that inhalation of radon and thoron daughters is the major radiation hazard from alpha radiation in uranium mining. The secondary scope of this report is the consideration of the applicability of the risk estimates derived from miners to the general public. The risk to members of the public from radium-226 in drinking water is also considered. Some research requirments are suggested

Recent advances in the estimation of genetic risks of exposure to ionizing radiation

International Nuclear Information System (INIS)

Sankaranarayanan, K.

2002-01-01

This paper reviews the major advances that have occurred during the last few years in the estimation of genetic risks of exposure of human populations to ionizing radiation. Among these are: (i) an upward revision of the estimates of the baseline frequencies of Mendelian diseases (from 1.25% to 2.4%); (ii) the conceptual change to the use of a doubling dose based on human data on spontaneous mutation rates and mouse data on induced mutation rates (from the one based entirely on mouse data on spontaneous and induced mutation rates, which was the case thus far); (iii) the fuller development of the concept of mutation component (MC) and its application to predict the responsiveness of Mendelian and chronic multi factorial diseases to induced mutations; (iv) the introduction of the concept that the major adverse effects of radiation exposure of human germ cells are likely to be manifest as multi-system developmental abnormalities and (v) the introduction of concept of potential recoverability correction factor (PRCF) to bridge the gap between induced mutations studied in mice and the risk of genetic disease in humans are reviewed

Improved Radiation Dosimetry/Risk Estimates to Facilitate Environmental Management Of Plutonium Contaminated Sites

International Nuclear Information System (INIS)

Scott, B.R.

2001-01-01

Currently available radiation dosimetry/health-risk models for inhalation exposure to radionuclides are based on deterministic radiation intake and deterministic radiation doses (local and global). These models are not adequate for brief plutonium (Pu) exposure scenarios related to Department of Energy (DOE) decontamination/decommissioning (D and D) operations because such exposures involve the stochastic-intake (StI) paradigm. For this paradigm, small or moderate numbers of airborne, pure, highly radioactive PuO2 particles could be inhaled and deposited in the respiratory tract in unpredictable numbers (stochastic) during D and D incidents. Probabilistic relationships govern intake via the respiratory tract for the StI paradigm. An StIparadigm incident occurred on March 16, 2000, at Los Alamos National Laboratory. It involved eight workers who inhaled high-specific-activity, alpha-emitting (HSA-aE) 238PuO2-contaminated room air (glovebox-failure incident). Health-risk estimation is not trivial for the StI-exposure paradigm, especially for HSA-aE 238PuO2, as different individuals can have very different and uncertain radioactivity intakes for the same exposure duration and same incident. Indeed, this occurred in the Los Alamos incident. Rather than inappropriate point estimates of intake, dose, and risk, more appropriate probability distributions are needed. A main objective of this project has been to develop a stochastic dosimetry/risk computer model for evaluating radioactivity intake (by inhalation) distributions, organ dose distributions, and health risk distributions for DOE workers who may inhale airborne, alpha-emitting, pure PuO2 at DOE sites such as Rocky Flats. Another objective of this project has been to address the deterministic intake (DI) paradigm where members of the public could inhale, over years, millions and more resuspended, air-transported, PuO2-contaminated dust particles while residing (e.g., farmer) or working (e.g., office worker) at a

Radiation induced cancer risk, detriment and radiation protection

International Nuclear Information System (INIS)

Sinclair, W.K.

1992-01-01

Recommendations on radiation protection limits for workers and for the public depend mainly on the total health detriment estimated to be the result of low dose ionizing radiation exposure. This detriment includes the probability of a fatal cancer, an allowance for the morbidity due to non-fatal cancer and the probability of severe hereditary effects in succeeding generations. In a population of all ages, special effects on the fetus particularly the risk of mental retardation at defined gestational ages, should also be included. Among these components of detriment after low doses, the risk of fatal cancer is the largest and most important. The estimates of fatal cancer risk used by ICRP in the 1990 recommendations were derived almost exclusively from the study of the Japanese survivors of the atomic bombs of 1945. How good are these estimates? Uncertainties associated with them, apart from those due to limitations in epidemiological observation and dosimetry, are principally those due to projection forward in time and extrapolation from high dose and dose rate to low dose and dose rate, each of which could after the estimate by a factor of 2 or so. Recent estimates of risk of cancer derived directly from low dose studies are specific only within very broad ranges of risk. Nevertheless, such studies are important as confirmation or otherwise of the estimates derived from the atomic bomb survivors. Recent U.S. British and Russian studies are examined in this light. (author)

New risk estimates at low doses

International Nuclear Information System (INIS)

Fry, R.J.M.

1992-01-01

The age of molecular radiation epidemiology may be at hand. The techniques are available to establish with the degree of precision required to determine whether agent-specific mutations can be identified consistently. A concerted effort to examine radiation-induced changes in as many relevant genes as possible appears to be justified. Cancers in those exposed to low doses of ionizing radiation should be chosen for the investigation. Parallel studies of radiation-induced cancers in experimental animals would not only complement the human studies, but perhaps reveal approaches to extrapolation of risk estimates across species. A caveat should be added to this optimistic view of what molecular studies might contribute to the knotty problem of risk estimates at low doses. The suggestions are made by one with no expertise in the field of molecular biology

Radiation exposure and risk of death

International Nuclear Information System (INIS)

Hongo, Syozo

1979-01-01

By using the risk factor given in ICRP publication 26 and an assumption of linear relationship between risk and dose, death rate and death number which correspond to radiation dose level and collective dose level of Japanese are estimated and they are compared with vital statistics of Japanese in 1975 to get out some ideas about radiation risk relative to the risks of everyday life. (author)

Ionizing radiation risks to satellite power systems (SPS) workers

International Nuclear Information System (INIS)

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

Ionizing radiation risks to satellite power systems (SPS) workers

Energy Technology Data Exchange (ETDEWEB)

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.

MCNPX dosimetry and radiation-induced cancer risk estimation from 18F-FDG pediatric PET at Brazilian population

International Nuclear Information System (INIS)

Mendes, Bruno M.; Fonseca, Telma C.F.; Campos, Tarcisio P.R.

2017-01-01

Positron emission tomography (PET) using 18 F-FDG has increased significantly in pediatric patients. PET with 18 F-FDG has often been applied in oncology. Cancer induction is one of the main stochastic risk from exposure to ionizing radiation of 18 F-FDG. Radiation-induced cancer risk estimation due to medical exposures is an important tool for risk/benefit assessing. The objective was to perform dosimetry and estimate the risk of cancer induction due to pediatric use of 18 F-FDG. MCNPX Computational dosimetry was performed to estimate organ absorbed doses resulting from 18 F-FDG pediatric use. Two voxelized phantoms, kindly provided by the GSF - Helmholtz Zentrum, were used: 'Child' - 7 years child and 'Baby' 8-week-old infant. ICRP-128 publication provided the radiopharmaceutical biodistribution of F-18. Tables containing organ absorbed dose and effective dose per unit of injected activity for the two phantoms were obtained. The injected activities were estimated according to data provided in the literature. Images of the absorbed dose distribution were generated from both models. The BEIR VII methodology was used to calculate the risk of cancer induction. The risk of cancer induction (per imaging procedure) for the seven-year-old child was (0.09% ♂ and 0.15% ♀) and for the eight-week old baby was (0.11% ♂ and 0.21% ♀). The 18 F-FDG absorbed dose distribution in the children and infants showed some divergences in comparison to adult data. Probably, the biokinetic data used to children and infants is the main reason for this disconnection. (author)

Modified Exponential (MOE) Models: statistical Models for Risk Estimation of Low dose Rate Radiation

International Nuclear Information System (INIS)

Ogata, H.; Furukawa, C.; Kawakami, Y.; Magae, J.

2004-01-01

Simultaneous inclusion of dose and dose-rate is required to evaluate the risk of long term irradiation at low dose-rates, since biological responses to radiation are complex processes that depend both on irradiation time and total dose. Consequently, it is necessary to consider a model including cumulative dose,dose-rate and irradiation time to estimate quantitative dose-response relationship on the biological response to radiation. In this study, we measured micronucleus formation and (3H) thymidine uptake in U2OS, human osteosarcoma cell line, as indicators of biological response to gamma radiation. Cells were exposed to gamma ray in irradiation room bearing 50,000 Ci 60Co. After irradiation, they were cultured for 24h in the presence of cytochalasin B to block cytokinesis, and cytoplasm and nucleus were stained with DAPI and propidium iodide. The number of binuclear cells bearing a micronucleus was counted under a florescence microscope. For proliferation inhibition, cells were cultured for 48 h after the irradiation and (3h) thymidine was pulsed for 4h before harvesting. We statistically analyzed the data for quantitative evaluation of radiation risk at low dose/dose-rate. (Author)

Perspectives of decision-making and estimation of risk in populations exposed to low levels of ionizing radiations

Energy Technology Data Exchange (ETDEWEB)

Fabrikant, J.I.

1979-01-01

The setting of any permissible radiation level or guide remains essentially an arbitrary procedure. Based on the radiation risk estimates derived, any lack of precision does not minimize either the need for setting public health policies nor the conclusion that such risks are extremely small when compared with those avialable of alternative options, and those normally accepted by society as the hazards of everyday life. When compared with the benefits that society has established as goals derived from the necessary activities of medical care and energy production, it is apparent that society must establish appropriate standards and seek appropriate controlling procedures which continue to assure that its needs are being met with the lowest possible risks. This implies continuing decision-making processes in which risk-benefit and cost-effectiveness assessments must be taken into account. Much of the practical information necessary for determination of radiation protection standards for public health policy is still lacking. It is now assumed that any exposure to radiaion at low levels of dose carries some risk of deleterious effects. However, how low this level may be, or the probability, or magnitude of the risk, still are not known. Radiation and the public health becomes a societal and political problem and not solely a scientific one. Our best scientific knowledge and our best scientific advice are essential for the protection of the public health, for the effective application of new technologies in medicine, and for guidance in the production of energy in industry. Unless man wishes to dispense with those activities which inevitably involve exposure to low levels of ionizing radiations, he must recognize that some degree of risk, however small, exists. In the evaluation of such risks from radiation, it is necessary to limit the radiation exposure to a level at which the risk is acceptable both to the individual and to society.

Perspectives of decision-making and estimation of risk in populations exposed to low levels of ionizing radiations

International Nuclear Information System (INIS)

Fabrikant, J.I.

1979-01-01

The setting of any permissible radiation level or guide remains essentially an arbitrary procedure. Based on the radiation risk estimates derived, any lack of precision does not minimize either the need for setting public health policies nor the conclusion that such risks are extremely small when compared with those avialable of alternative options, and those normally accepted by society as the hazards of everyday life. When compared with the benefits that society has established as goals derived from the necessary activities of medical care and energy production, it is apparent that society must establish appropriate standards and seek appropriate controlling procedures which continue to assure that its needs are being met with the lowest possible risks. This implies continuing decision-making processes in which risk-benefit and cost-effectiveness assessments must be taken into account. Much of the practical information necessary for determination of radiation protection standards for public health policy is still lacking. It is now assumed that any exposure to radiaion at low levels of dose carries some risk of deleterious effects. However, how low this level may be, or the probability, or magnitude of the risk, still are not known. Radiation and the public health becomes a societal and political problem and not solely a scientific one. Our best scientific knowledge and our best scientific advice are essential for the protection of the public health, for the effective application of new technologies in medicine, and for guidance in the production of energy in industry. Unless man wishes to dispense with those activities which inevitably involve exposure to low levels of ionizing radiations, he must recognize that some degree of risk, however small, exists. In the evaluation of such risks from radiation, it is necessary to limit the radiation exposure to a level at which the risk is acceptable both to the individual and to society

Possibility of use of plant test systems for estimation of degree risk at radiation influence

International Nuclear Information System (INIS)

Gogebashvili, M.E; Ivanishvili, N.I.

2011-01-01

Full tex:Now one of the major problems of radiobiology is studying of degree risks at influence of small doses of an ionizing radiation. It is known, that not tumoral forms of the remote pathology are not stochastic, threshold, reactions of an organism to beam influence, frequency and weight depend on a dose, while carcinogenic and genetic effects (stochastic reactions) - frequency raises with dose increase. Last years the general hypothesis for definition of the raised risk in the irradiated populations, based on the theoretical analysis of extensive researches of various biological objects and epidemiological data, assumes existence of difficult parities between a dose of an irradiation and frequency of investigated effect. In this aspect the special importance is got by biological models with which help reception of quantitative parameters of influence of modifying factors for creation of more exact systems of monitoring of the remote radiobiological effects is possible.One of such systems is reciprocal grows reaction of stamen threads of plant tradescantia. At the heart of action of the given biomodel that growth tradescantia threads occurs from one initial cell is, and level of its radiating damage is shown in number of the subsequent cellular generation during the postradiating period. For an estimation of adequacy of the given model we had been chose two kinds tradescantia - Tradescantia virginiana L. and Tradescantia rosea Vent.In work two basic criteria of an estimation of radiating damage - quantity of viable pollen threads and quantity of viable cells in each of threads have been used. The received results have shown strict correlation of reciprocal postradiating effects between used variants.It is known, that at studying of influence of damaging factors of environment, including radiating, on live organisms the concept r iskcharacterizes degree of danger of influence expressed in quantity indicators. Thus, in most general case this includes probability

Ionizing radiation, genetic risks and radiation protection

International Nuclear Information System (INIS)

Sankaranarayanan, K.

1992-01-01

With one method of risk estimation, designed as the doubling dose method, the estimates of total genetic risk (i.e., over all generation) for a population continuously exposed at a rate of 0.01 Gy/generation of low LET irradiation are about 120 cases of Mendelian and chromosomal diseases/10 6 live births and about the same number of cases for multifactorial diseases (i.e., a total of 240 cases/10 6 ). These estimates provide the basis for risk coefficients for genetic effects estimated by ICRP (1991) in its Publication 60. These are: 1.0%/Sv for the general population (which is 40% of 240/10 6 /0.01 Gy), and 0.6%/Sv for radiation workers (which is 60% of that for the general population). The results of genetic studies carried out on the Japanese survivors of A-bombs have shown no significant adverse effects attributable to parental radiation exposures. The studies of Gardner and colleagues suggest that the risk of leukaemia in children born to male workers in the nuclear reprocessing facility in Sellafield, U.K., may be increased. However, this finding is at variance with the results from the Japanese studies and at present, does not lend itself to a simple interpretation based on radiobiological principles. In the light of recent advances in the molecular biology of naturally-occurring human Mendelian diseases and what we presently know about multifactorial diseases, arguments are advanced to support the thesis that (i) current risk estimates for Mendelian diseases may be conservative and (ii) an overall doubling dose for all adverse genetic effects may be higher than the 1 Gy currently used (i.e., the relative risks are probably lower). (author)

Cancer risks after radiation exposures

International Nuclear Information System (INIS)

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

Radiation risks in perspective

International Nuclear Information System (INIS)

Pochin, E.E.

1987-01-01

The problem of risk assessment is greater at the low effective dose rates now observed in the majority of all forms of exposure, usually of less than 3 mSv per year from natural causes, from occupational exposure, and from exposure of 'critical groups' of the general public. For most populations there are particular problems also in epidemiological studies at low dose, in addition to those due to the very large numbers of person-years that need to be studied and the long latencies of most radiation effects. Adequate estimates can, however, now be made of the carcinogenic risk of exposure at higher dose of various organs selectively and of the whole body uniformly, and of modes of inference to the risk at lower dose. Estimates can also be made of the risks of inducing major types of inheritable and developmental abnormality. An essential step in viewing the sum of all such radiation risks in the perspective of other occupational and public risks must now be to develop an informed consensus on the relative weight that is regarded as attaching to hazards of different kind and severity. (author)

Methods to estimate the genetic risk

International Nuclear Information System (INIS)

Ehling, U.H.

1989-01-01

The estimation of the radiation-induced genetic risk to 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 dose not. There are two main approaches in making genetic risk estimates. One of these, termed the direct method, expresses risk in terms of expected frequencies of genetic changes induced per unit dose. The other, referred to as the doubling dose method or the indirect method, expresses risk in relation to the observed incidence of genetic disorders now present in man. The advantage of the indirect method is that not only can Mendelian mutations be quantified, but also other types of genetic disorders. The disadvantages of the method are the uncertainties in determining the current incidence of genetic disorders in human and, in addition, the estimasion of the genetic component of congenital anomalies, anomalies expressed later and constitutional and degenerative diseases. Using the direct method we estimated that 20-50 dominant radiation-induced mutations would be expected in 19 000 offspring born to parents exposed in Hiroshima and Nagasaki, but only a small proportion of these mutants would have been detected with the techniques used for the population study. These methods were used to predict the genetic damage from the fallout of the reactor accident at Chernobyl in the vicinity of Southern Germany. The lack of knowledge for the interaction of chemicals with ionizing radiation and 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. (author)

Occupational radiation risk to radiologists

International Nuclear Information System (INIS)

Schuettmann, W.

1981-01-01

A review is given of the most important publications dealing with attempts to estimate the occupational radiation risk to radiologists by comparing data on their mortality from leukemia and other forms of cancer with respective data for other physicians who were not occupationally exposed to ionizing radiation. (author)

Genetic risks from radiation: recent assessments by the BEIR and UNSCEAR Committees and suggestions as to how future research can improve such estimates

International Nuclear Information System (INIS)

Selby, P.B.

1979-01-01

Recently two widely-recognized committees, namely the UNSCEAR and BEIR Committees, have reevaluated their estimates of genetic risks from radiation. Their estimates for gene mutations are based on two different approaches, one being the doubling-dose approach and the other being a new direct approach based on an empirical determination of the amount of dominant induced damage in the skeletons of mice in the first generation following irradiation. The estimates made by these committees are in reasonably good agreement and suggest that the genetic risks from present exposures resulting from nuclear power production are small. There is room for much improvement in the reliability of the risk estimates. The relatively new approach of measuring the amount of induced damage to the mouse skeleton shows great promise of improving knowledge about how changes in the mutation frequency affect the incidence of genetic disorders. Such findings may have considerable influence on genetic risk estimates for radiation and on the development of risk estimates for other less-well-understood environmental mutagens

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

International Nuclear Information System (INIS)

Scott, Bobby R.

1999-01-01

The objective of this research is to evaluate distributions of possible alpha radiation doses to the lung, bone, and liver, and associated health-risk distributions for plutonium (Pu) inhalation exposure scenarios relevant to environmental management of PuO2-contaminated sites. Currently available dosimetry/risk models do not apply to exposure scenarios where relatively small numbers of highly radioactive PuO2 particles are presented for inhalation (stochastic exposure [SE] paradigm). For the SE paradigm, distributions of possible risks are more relevant than point estimates of risk. The main goal of the project is to deliver a computer program that will allow evaluation of the indicated risk distributions for the SE paradigm. However, some of our work also relates to the deterministic exposure [DE] paradigm where large numbers of airborne particles (resuspended dust containing PuO2) are presented for inhalation to members of the public residing or working at a remediated Department of Energy (DOE) site

NASA Space Radiation Program Integrative Risk Model Toolkit

Science.gov (United States)

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.

Combining Radiation Epidemiology With Molecular Biology-Changing From Health Risk Estimates to Therapeutic Intervention.

Science.gov (United States)

Abend, Michael; Port, Matthias

2016-08-01

The authors herein summarize six presentations dedicated to the key session "molecular radiation epidemiology" of the ConRad meeting 2015. These presentations were chosen in order to highlight the promise when combining conventional radiation epidemiology with molecular biology. Conventional radiation epidemiology uses dose estimates for risk predictions on health. However, combined with molecular biology, dose-dependent bioindicators of effect hold the promise to improve clinical diagnostics and to provide target molecules for potential therapeutic intervention. One out of the six presentations exemplified the use of radiation-induced molecular changes as biomarkers of exposure by measuring stabile chromosomal translocations. The remaining five presentations focused on molecular changes used as bioindicators of the effect. These bioindicators of the effect could be used for diagnostic purposes on colon cancers (genomic instability), thyroid cancer (CLIP2), or head and neck squamous cell cancers. Therapeutic implications of gene expression changes were examined in Chernobyl thyroid cancer victims and Mayak workers.

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

Science.gov (United States)

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.

MCNPX dosimetry and radiation-induced cancer risk estimation from {sup 18}F-FDG pediatric PET at Brazilian population

Energy Technology Data Exchange (ETDEWEB)

Mendes, Bruno M.; Fonseca, Telma C.F. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Campos, Tarcisio P.R., E-mail: bmm@cdtn.br, E-mail: tcff@cdtn.br, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (PCTN/UFMG), Belo Horizonte, MG (Brazil). Programa de Pós-Graduação em Ciências e Técnicas Nucleares

2017-07-01

Positron emission tomography (PET) using {sup 18}F-FDG has increased significantly in pediatric patients. PET with {sup 18}F-FDG has often been applied in oncology. Cancer induction is one of the main stochastic risk from exposure to ionizing radiation of {sup 18}F-FDG. Radiation-induced cancer risk estimation due to medical exposures is an important tool for risk/benefit assessing. The objective was to perform dosimetry and estimate the risk of cancer induction due to pediatric use of {sup 18}F-FDG. MCNPX Computational dosimetry was performed to estimate organ absorbed doses resulting from {sup 18}F-FDG pediatric use. Two voxelized phantoms, kindly provided by the GSF - Helmholtz Zentrum, were used: 'Child' - 7 years child and 'Baby' 8-week-old infant. ICRP-128 publication provided the radiopharmaceutical biodistribution of F-18. Tables containing organ absorbed dose and effective dose per unit of injected activity for the two phantoms were obtained. The injected activities were estimated according to data provided in the literature. Images of the absorbed dose distribution were generated from both models. The BEIR VII methodology was used to calculate the risk of cancer induction. The risk of cancer induction (per imaging procedure) for the seven-year-old child was (0.09% ♂ and 0.15% ♀) and for the eight-week old baby was (0.11% ♂ and 0.21% ♀). The {sup 18}F-FDG absorbed dose distribution in the children and infants showed some divergences in comparison to adult data. Probably, the biokinetic data used to children and infants is the main reason for this disconnection. (author)

Radon and its decay products in living spaces: estimation of radiation exposure and risks for radon levels measured in Switzerland

International Nuclear Information System (INIS)

Burkart, W.

1984-03-01

After a general introduction to radiation levels, radon and its daughter products are considered. Radon in living spaces is discussed, in particular the radon concentration in family houses. The influence of energy saving characteristics on the radon concentration in the indoor air includes a 'matched pair' analysis and ventilation installations and dwell duration of indoor air noxious agents. Estimation of the radiation risks are determined, including risks of lung cancer, human epidemiological investigations (miners and radiation levels in living spaces), and possible results of energy saving characteristics. Finally characteristics and recommendations in general are given. (A.N.K.)

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

Energy Technology Data Exchange (ETDEWEB)

Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P. [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Department of Physics, and Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Duke Radiation Dosimetry Laboratory, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Duke Radiation Dosimetry Laboratory, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Division of Pediatric Radiology, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States)

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

Estimated risk for secondary cancer in the contra-lateral breast following radiation therapy of breast cancer

International Nuclear Information System (INIS)

Johansen, Safora; Danielsen, Turi; Olsen, Dag Rune

2008-01-01

Purpose. To facilitate a discussion about the impact of dose heterogeneity on the risk for secondary contralateral breast (CB) cancer predicted with linear and non linear models associated with primary breast irradiation. Methods and materials. Dose volume statistics of the CB calculated for eight patients using a collapsed cone algorithm were used to predict the excess relative risk (ERR) for cancer induction in CB. Both linear and non-linear models were employed. A sensitivity analysis demonstrating the impact of different parameter values on calculated ERR for the eight patients was also included in this study. Results. A proportionality assumption was established to make the calculations with a linear and non-linear model comparable. ERR of secondary cancer predicted by the linear model varied considerably between the patients, while the predicted ERR for the same patients using the non-linear model showed very small variation. The predicted ERRs by the two models were indistinguishable for small doses, i.e. below ∼3 Gy. The sensitivity analysis showed that the quadratic component of the radiation-induction pre-malignant cell term is negligible for lower dose level. The ERR is highly sensitive to the value of agr1 and agr2. Conclusions. Optimization of breast cancer radiation therapy, where also the risk for radiation induced secondary malignancies in the contralateral breast is taken into account, requires robust and valid risk assessment. The linear dose-risk model does not account for the complexity in the mechanisms underlying the development of secondary malignancies following exposure to radiation; this is particularly important when estimating risk associated with highly heterogeneous dose distributions as is the case in the contralateral breast of women receiving breast cancer irradiation

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-12-14

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Low-dose extrapolation of radiation health risks: some implications of uncertainty for radiation protection at low doses.

Science.gov (United States)

Land, Charles E

2009-11-01

Ionizing radiation is a known and well-quantified human cancer risk factor, based on a remarkably consistent body of information from epidemiological studies of exposed populations. Typical examples of risk estimation include use of Japanese atomic bomb survivor data to estimate future risk from radiation-related cancer among American patients receiving multiple computed tomography scans, persons affected by radioactive fallout, or persons whose livelihoods involve some radiation exposure, such as x-ray technicians, interventional radiologists, or shipyard workers. Our estimates of radiation-related risk are uncertain, reflecting statistical variation and our imperfect understanding of crucial assumptions that must be made if we are to apply existing epidemiological data to particular situations. Fortunately, that uncertainty is also highly quantifiable, and can be presented concisely and transparently. Radiation protection is ultimately a political process that involves consent by stakeholders, a diverse group that includes people who might be expected to be risk-averse and concerned with plausible upper limits on risk (how bad could it be?), cost-averse and concerned with lower limits on risk (can you prove there is a nontrivial risk at current dose levels?), or combining both points of view. How radiation-related risk is viewed by individuals and population subgroups also depends very much on perception of related benefit, which might be (for example) medical, economic, altruistic, or nonexistent. The following presentation follows the lead of National Council on Radiation Protection and Measurements (NCRP) Commentary 14, NCRP Report 126, and later documents in treating radiation protection from the viewpoint of quantitative uncertainty analysis.

Radiobiological risk estimates of adverse events and secondary cancer for proton and photon radiation therapy of pediatric medulloblastoma

DEFF Research Database (Denmark)

Brodin, N Patrik; Munck af Rosenschöld, Per Martin; Aznar, Marianne C

2011-01-01

The aim of this model study was to estimate and compare the risk of radiation-induced adverse late effects in pediatric patients with medulloblastoma (MB) treated with either three-dimensional conformal radiotherapy (3D CRT), inversely-optimized arc therapy (RapidArc(®) (RA)) or spot...

Sarcoma risk after radiation exposure

Directory of Open Access Journals (Sweden)

Berrington de Gonzalez Amy

2012-10-01

Full Text Available Abstract Sarcomas were one of the first solid cancers to be linked to ionizing radiation exposure. We reviewed the current evidence on this relationship, focusing particularly on the studies that had individual estimates of radiation doses. There is clear evidence of an increased risk of both bone and soft tissue sarcomas after high-dose fractionated radiation exposure (10 + Gy in childhood, and the risk increases approximately linearly in dose, at least up to 40 Gy. There are few studies available of sarcoma after radiotherapy in adulthood for cancer, but data from cancer registries and studies of treatment for benign conditions confirm that the risk of sarcoma is also increased in this age-group after fractionated high-dose exposure. New findings from the long-term follow-up of the Japanese atomic bomb survivors suggest, for the first time, that sarcomas can be induced by acute lower-doses of radiation (

Leukaemia and thyroid cancer in emergency workers of the Chernobyl accident:. Estimation of radiation risks (1986-1995)

International Nuclear Information System (INIS)

Ivanov, V.K.; Tsyb, A.F.; Gorsky, A.I.; Maksyutov, M.A.; Rastopchin, E.M.; Konogorov, A.P.; Korelo, A.M.; Biryukov, A.P.; Matyash, V.A.

1997-01-01

This work focuses on the direct epidemiological assessment of the risks of radiation-induced leukaemia and thyroid cancer in emergency workers (EW) after the Chernobyl accident. The Russian National Medical Dosimetric Registry (RNMDR) contains data for 168 000 EW as of January 1, 1996. The analysis relates to 48 leukaemias and 47 thyroid cancers, diagnosed and verified. Radiation risks are estimated by comparing the EW data with national data for a male population of the same age distribution. For leukaemia, an excess relative risk per Gy (ERR/Gy) of 4.30 (95% CI: 0.83, 7.75) is obtained, while the excess absolute risk per 10 4 person-years (PY) Gy (EAR/10 4 PY Gy) is found to be 1.31 (95% CI: 0.23, 2.39); for thyroid cancer an ERR/Gy of 5.31 (95% CI: 0.04, 10.58) is obtained, and an EAR/10 4 PY Gy of 1.15 (95% CI: 0.08, 2.22). (orig.). With 9 figs., 10 tabs

Estimation of cancer risks from radiotherapy of benign diseases

International Nuclear Information System (INIS)

Trott, K.R.; Kamprad, F.

2006-01-01

Background: The effective-dose method which was proposed by the ICRP (International Commission of Radiation Protection) for the estimation of risk to the general population from occupational or environmental, low-dose radiation exposure is not adequate for estimating the risk of cancer induction by radiotherapy of malignant or nonmalignant diseases. Methods:The risk of cancer induction by radiotherapy of benign diseases should be based on epidemiologic data directly derived from follow-up studies of patients who had been given radiotherapy for nonmalignant diseases in the past. Results: Risk factors were derived from epidemiologic studies of patients treated with irradiation for nonmalignant diseases to be used for selecting treatment options and optimizing treatment procedures. Conclusion: In most cases, cancer risks estimated by the effective-dose method may overestimate the true risks by one order of magnitude, yet in other cases even may underestimate it. The proposed method using organ-specific risk factors may be more suitable for treatment planning. (orig.)

Uranium mill tailings and risk estimation

International Nuclear Information System (INIS)

Marks, S.

1984-04-01

Work done in estimating projected health effects for persons exposed to mill tailings at vicinity properties is described. The effect of the reassessment of exposures at Hiroshima and Nagasaki on the risk estimates for gamma radiation is discussed. A presentation of current results in the epidemiological study of Hanford workers is included. 2 references

Estimating cancer risks to adults undergoing body CT examinations

International Nuclear Information System (INIS)

Huda, W.; He, W.

2012-01-01

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

Risks of low-level radiation - the evidence of epidemiology

International Nuclear Information System (INIS)

Gloag, D.

1980-01-01

The difficulties involved in estimating risks from very low levels of radiation and the use of dose-response models for cancer incidence are discussed with reference to the third BEIR Committee report on the Effects on Populations of Exposure to low levels of Ionizing Radiation (1980). Cancer risk estimates derived from different epidemiological studies are reviewed. They include atom bomb survivors, medically irradiated groups and occupational groups. (36 references). (author)

Studies on risk estimation to public from medical radiation (III)

Energy Technology Data Exchange (ETDEWEB)

Lee, Hai Yong; Kim, Jong Hyung; Kim, Hyeog Ju; Kim, Ji Soon; Oh, Hyeon Joo; Kim, Cheol Hyeon; Yang, Hyun Kyu [Korea Food and Drug Administraion, Seoul (Korea, Republic of); Park, Chan Il [Seoul National Univ., Seoul (Korea, Republic of)

1998-06-01

A nationwide survey was conducted to give representative levels of effective doses to patient for 17 types of CT examination and also representative level of MGD (mean glandular dose) to standard breast for mammography X-ray equipment. The effective doses to patient from 16 CT scanners were estimated from measurement of CTDI (Computed Tomography Dose Index) in air by multiplying conversion coefficients which are specified by National Radiological Protection Board in United Kingdom. The lowest and hightest mean values of effective dose measured to patient from CT scanner were 0.05 mSv for IAM examination and 17.75 mSv for routine abdomen examination, respectively. The average values of 17 effective doses were lower than other results of foreign countrys' surveys. The mean glandular doses to a standard breast for 26 mammography units were estimated from measurement of the air kerma at the surface of a 40 mm plain Perspex phantom by applying conversion factors described in Report 59 of the Institute of Physical Sciences in Medicine of United Kingdom. The exposure factors for this measurement were those used clinically at each hospital. The average MGD to standard breast was 1.06 mGy in units with grid and 0.49 mGy in units without grid. These results are lower than guidance levels by IPSM and AAPM. These results will be used for risk estimation to the Korean public from the medical radiation.

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

International Nuclear Information System (INIS)

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

Cancer risk from low doses of ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Auvinen, A

1997-06-01

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

Cancer risk from low doses of ionizing radiation

International Nuclear Information System (INIS)

Auvinen, A.

1997-06-01

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

Radiation quality and radiation risks - some current problems

International Nuclear Information System (INIS)

Kellerer, A.M.; Hahn, K.

1989-01-01

The newly evaluated cancer mortality data of the atomic bomb survivors suggest substantially enhanced risk estimates, and the various factors that are involved in the change are considered. The enhanced risk estimates have already led to added restrictions in the dose limits for radiation workers, and there may be a further tightening of regulations in the future. The impending revision of the quality factors in radiation protection may, therefore, lead to practical difficulties, and a careful consideration of the various aspects involved in a revision is required. A liaison group of ICRU and ICRP has proposed a reformulation of the quality factor that is related not to the LET, but to the microdosimetric variably y. The relation leads to increased quality factors for neutrons, but also to a quality factor for γ rays of only 0.5. Alternatives are presented that relate the quality factor to LET and that retain γ- rays as the reference radiation. One option corresponds to different quality factors for γ rays and X-rays, the other option sets the quality factor for photons approximately equal to unity, irrespective of energy. (author)

Using mortality data to estimate radiation effects on breast cancer incidence

International Nuclear Information System (INIS)

Hoel, D.G.; Dinse, G.E.

1990-01-01

In this paper we combine Japanese data on radiation exposure and cancer mortality with U.S. data on cancer incidence and lethality to estimate the effects of ionizing radiation on cancer incidence. The analysis is based on the mathematical relationship between the mortality rate and the incidence and lethality rates, as well as on statistical models that relate Japanese incidence rates to U.S. incidence rates and radiation risk factors. Our approach assumes that the risk of death from causes other than the cancer does not depend on whether or not the cancer is present, and among individuals with the cancer, the risk of death attributable to the cancer is the same in Japan and the U.S. and is not affected by radiation exposure. In particular, we focus on the incidence of breast cancer in Japanese women and how this incidence is affected by radiation risk factors. The analysis uses Japanese exposure and mortality data from the Radiation Effects Research Foundation study of atomic bomb survivors and U.S. incidence and lethality data from the Surveillance, Epidemiology, and End Results Registry. Even without Japanese incidence data, we obtain reasonable estimates of the incidence of breast cancer in unexposed Japanese women and identify the radiation risk factors that affect this incidence. Our analysis demonstrates that the age at exposure is an important risk factor, but that the incidence of breast cancer is not affected by the city of residence (Nagasaki versus Hiroshima) or the time since exposure

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

Science.gov (United States)

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.

Medical radiological consequences of the Chernobyl catastrophe in Russia. Estimation of radiation risks

International Nuclear Information System (INIS)

Ivanov, V.; Tsyb, A.; Ivanov, S.; Pokrovsky, V.

2004-01-01

The Chernobyl accident, one of the worst radiation-related disasters ever, occurred about 18 year ago. A lot has been done over the past years to mitigate the consequences of this accident, especially in the worst affected territories of Belarus, Russia and Ukraine. The efforts to study health effects of the accident, however, need to be continued for many years to come, being an integral part of developing a general strategy for dealing with long-term effects. The question now arises: To what extent health consequences could be evaluated in 1986, given the existing scientific base of radiation epidemiology? The latest 20-30 years have seen a rapid development of radiation epidemiology, which was brought about, first of all, by the need to analyze long-term radiation effects of the 1945 atomic bombing in Hiroshima and Nagasaki. It may now be considered as proved that high and medium radiation doses (above 0.3 Sv) lead to an increase in cancer incidence rates. Based on the Japanese data, the ICRP proposed mathematical models to be used for predicting long-term effects of radiation exposure. This brings up a question: Are radiation risks derived for Hiroshima and Nagasaki applicable to low doses (0.2 Sv)? An answer is critically important, as the overwhelming majority of emergency workers and the population exposed as a result of the Chernobyl accident received doses within this range. Actually, understanding of these issues is crucial for dealing with long-term radiation effects of the Chernobyl accident. Deriving radiation risk factors for the Japanese cohort with medium and high doses was based on large-scale epidemiological studies of 86.5 thousand people during a prolonged period. As of now, no other approaches exist to estimating long-term radiation effects. Following the Chernobyl accident the All-Union Distributed Registry of persons exposed to radiation was established as soon as in the summer 1986. The Research Institute of Medical Radiology (Medical

Radiation dose and cancer risk among pediatric patients undergoing interventional neuroradiology procedures

International Nuclear Information System (INIS)

Thierry-Chef, Isabelle; Simon, Steven L.; Miller, Donald L.

2006-01-01

During interventional neuroradiology procedures, patients can be exposed to moderate to high levels of radiation. Special considerations are required to protect children, who are generally more sensitive to the short- and long-term detrimental effects of radiation exposure. Estimates of dose to the skin of children from certain interventional procedures have been published elsewhere, but we are not aware of data on dose to the brain or on the long-term risk of cancer from brain radiation. Our goals were to estimate radiation doses to the brain in 50 pediatric patients who had undergone cerebral embolization and to assess their lifetime risks of developing radiation-related brain cancer. Entrance-peak skin dose and various assumptions on conditions of exposure were used as input for dosimetric calculations to estimate the spatial pattern of dose within the brain and the average dose to the whole brain for each child. The average dose and the age of the child at time of exposure were used to estimate the lifetime risk of developing radiation-related brain cancer. Among the 50 patients, average radiation doses to the brain were estimated to vary from 100 mGy to 1,300 mGy if exposed to non-collimated fields and from 20 mGy to 160 mGy for collimated, moving fields. The lifetime risk of developing brain cancer was estimated to be increased by 2% to 80% as a result of the exposure. Given the very small lifetime background risk of brain tumor, the excess number of cases will be small even though the relative increase might be as high as 80%. ALARA principles of collimation and dose optimization are the most effective means to minimize the risk of future radiation-related cancer. (orig.)

Factors that modify risks of radiation-induced cancer

International Nuclear Information System (INIS)

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)

Radiation risk - historical perspective and current issues

Energy Technology Data Exchange (ETDEWEB)

Kellerer, Albrecht M. [Strahlenbiologisches Institut, Ludwig-Maximilians-Universitaet, Munich, Germany and Institute for Radiation Biology, GSF-National Research Center for Environment and Health, Neuherberg (Germany)

2002-09-01

The assessment of radiation risk needs to be seen against the background of a historical development that has reversed the initial belief in a general beneficial effect of radiation to apprehension and fear. Numerical risk estimates are, today, based on large epidemiological studies, and the observations on the A-bomb survivors are outlined as the primary source of information. Since the epidemiological findings are obtained from relatively high radiation exposures, extrapolations are required to the much lower doses that are relevant to radiation protection. The evolution of extrapolation procedures up to current attempts at mechanistic modelling is outlined, and some of the open issues are reviewed. (author)

Radiation risk - historical perspective and current issues

International Nuclear Information System (INIS)

Kellerer, Albrecht M.

2002-01-01

The assessment of radiation risk needs to be seen against the background of a historical development that has reversed the initial belief in a general beneficial effect of radiation to apprehension and fear. Numerical risk estimates are, today, based on large epidemiological studies, and the observations on the A-bomb survivors are outlined as the primary source of information. Since the epidemiological findings are obtained from relatively high radiation exposures, extrapolations are required to the much lower doses that are relevant to radiation protection. The evolution of extrapolation procedures up to current attempts at mechanistic modelling is outlined, and some of the open issues are reviewed. (author)

Radiation risks for patients having X rays

International Nuclear Information System (INIS)

Hale, J.; Thomas, J.W.

1985-01-01

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

Radiation dose estimates for carbon-11-labelled PET tracers

International Nuclear Information System (INIS)

Aart, Jasper van der; Hallett, William A.; Rabiner, Eugenii A.; Passchier, Jan; Comley, Robert A.

2012-01-01

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

Radiation risk due to occupational exposure

International Nuclear Information System (INIS)

Kargbo, A.A

2012-04-01

Exposure to ionizing radiation occurs in many occupations. Workers can be exposed to both natural and artificial sources of radiation. Any exposure to ionizing radiation incurs some risk, either to the individual or to the individual's progeny. This dissertation investigated the radiation risk due to occupational exposure in industrial radiography. Analysis of the reported risk estimates to occupational exposure contained in the UNSCEAR report of 2008 in industrial radiography practice was done. The causes of accidents in industrial radiography include: Lack of or inadequate regulatory control, inadequate training, failure to follow operational procedures, human error, equipment malfunction or defect, inadequate maintenance and wilful violation have been identified as primary causes of accidents. To minimise radiation risks in industrial radiography exposure devices and facilities should be designed such that there is intrinsic safety and operational safety ensured by establishing a quality assurance programme, safety culture fostered and maintained among all workers, industrial radiography is performed in compliance with approved local rules, workers engaged have appropriate qualifications and training, available safe operational procedures are followed, a means is provided for detecting incidents and accidents and an analysis of the causes and lessons learned. (author)

Information from the National Institute of Radiation Protection about radiation doses and radiation risks at x-ray screening

International Nuclear Information System (INIS)

1975-05-01

This report gives a specification of data concerning radiation doses and risks at x-ray investigations of lungs. The dose estimations are principally based on measurements performed in 1974 by the National Institute of Radiation Protection. The radiation doses at x-ray screening are of that magnitude that the risk for acute radiation injuries is non-existent. At these low doses it has not either been able to prove that the radiation gives long-range effects as changes in the genes or cancer of late appearance. At considerable higher doses, more than tens of thousands of millirads, a risk of cancer appearance at a small part of all irradiated persons has been proved, based on the assumption that the cancer risk is proportional to the radiation dose. Cancer can thus occure at low radiation doses too. Because of the mass radiography in Sweden 1974 about twenty cases of cancer may appear in the future. (M.S.)

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

Science.gov (United States)

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.

A-BOMB SURVIVOR SITE-SPECIFIC RADIOGENIC CANCER RISKS ESTIMATES

Science.gov (United States)

A draft manuscript is being prepared that describes ways to improve estimates of risk from radiation that have been derived from A-bomb survivors. The work has been published in the journal Radiation Research volume 169, pages 87-98.

Low-level radiation: a review of current estimates of hazards to human populations

International Nuclear Information System (INIS)

Myers, D.K.

1977-12-01

Mankind has always lived with low levels of ionizing radiation from natural sources. This ionizing radiation may induce cancers in irradiated persons and genetic defects in the descendents of irradiated persons. The internationally accepted estimates of risks suggest that the numbers of cancers and genetic defects induced in the general population by natural background radiation are not more than about 1% of the numbers of cancers and genetic defects normally present in the general population. The added risks to the general public due to any prospective nuclear power program are minute compared to those from background radiation. At the maximum permissible levels of radiation exposures for occupational workers, the predicted number of fatal cancers induced would lead to a reduction in average life-span from 73.0 years to about 72.7 years. Since occupational exposures are usually much less than maximum permissible levels, the risks are correspondingly reduced. These occupational risks are comparable to those in most other industries and occupations. Some areas of uncertainty in the accepted risk estimates are discussed in detail in this review. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Kettunen, A. [Oulu Univ. (Finland)

2004-05-01

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

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

International Nuclear Information System (INIS)

Kettunen, A.

2004-05-01

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

Summary of the BEIR V committee's estimates of genetic risks

International Nuclear Information System (INIS)

Grahn, D.

1990-01-01

The Committee on the Biological Effects of Ionizing Radiations (BEIR V) was constituted in late 1986 to conduct a comprehensive review of the biological effects of ionizing radiations focusing on information reported since the conclusion of the 1980 BEIR study, and to provide new estimates of the risks of genetic and somatic effects in humans due to low-level exposures of ionizing radiation. The Committee preferred the doubling-dose method of genetic risk estimation over the direct method. Data from animal (mouse) studies provide a median value of 100 to 114 cGy for long-term low dose rate exposure doubling doses. These values are lower than the median from human studies. The BEIR Committee believed that a doubling dose of 100 cGy would be a prudent value leading to conservative estimates. The estimated risks themselves are not much different from those generated by previous BEIR committees, UNSCEAR, and other published estimates. The Committee estimates that between 100 and 200 added cases per million live births will be observed at genetic equilibrium if the population is exposed each generation to a dose of 0.01 Sv (1 rem). Nearly half ware attributed to clinically mild dominant defects, and the balance to congenital abnormalities. (L.L.) (2 tabs.)

Estimation of enhanced cancer risk with 18FDG PET/CT investigations

International Nuclear Information System (INIS)

Kaushik, Aruna; Mishra, Anil K.; Sharma, Rajnish; Mondal, Anupam; Dwarakanath, B.S.

2014-01-01

18 F-Fluorodeoxyglucose ( 18 FDG) Positron Emission Tomography/Computed Tomography (PET/CT) investigation involves internal administration of 18 FDG and use of CT X-rays for the purpose of obtaining functional and anatomical information of a patient. However, the radiation exposure from undergoing PET/CT investigation may enhance the risk of cancer incidence as per the Linear-No-Threshold (LNT) model. The objective of the present study was to quantify the risk of cancer incidence associated with radiation exposure from 18 FDG PET/CT investigations. The organ doses from internally administered 18 FDG were estimated using OLINDA/EXM Code by performing dynamic PET scans in different regions of the body in a total of forty-nine patients. Organ doses from the CT component were calculated using the software CT-Expo. The associated cancer risk was calculated in terms of life time risk of cancer incidence resulting from a specified dose of ionizing radiation and was expressed in terms of Lifetime Attributable Risk (LAR). LAR values and the organ doses estimated for males and females were used to estimate the lifetime risk of cancer incidence from whole body 18 FDG PET/CT scan. Since from 18 FDG whole body PET/CT investigations, various tissues of the body receive substantially different doses, the site specific risk of cancer incidence was estimated and summed to obtain the total risk. This was compared with the baseline lifetime risk of cancer incidence in Indian population. LAR of cancer incidence was observed to be relatively higher in females as compared to males. The risk estimates ranged from 0.36% to 0.49% for a 20 year old male and 0.58% to 0.79% for a 20 year old female and were observed to be higher in younger ages and decreased with age. 18 FDG whole body PET/CT investigation was observed to be associated with non-negligible radiation risk as compared to the risks associated with other diagnostic modalities. (author)

The importance of radiation risk assessment

International Nuclear Information System (INIS)

Pochin, E.E.

1979-01-01

In its Publication 26, ICRP recommends a system of radiation dose limitation that is designed to ensure adequate protection from the harmful effects of radiation in conditions both of occupational and of environmental exposure. Clearly, however, no such system can be recommended or accepted as sufficiently safe unless the risks of the resultant exposures have been quantitatively assessed. Publication 26 reflects the increasing quantitative information that is now available on (a) carcinogenic risks of radiation in man, both from exposure of the whole body and from that of individual organs, at moderate exposures; (b) theoretical bases for inference of risk, from moderate to lower exposures; (c) genetic risks in the mouse, and inferences from such risks to those in man; (d) the dose equivalent levels at which certain non-stochastic effects may be induced. Despite a number of uncertainties, substantially improved estimates can therefore be made of the levels of safety that are likely to be achieved by observing the Commission's recommended dose limits, and the associated system of limitation of exposures to levels as low as reasonably achievable below these limits. Both for occupational exposure and for the exposure of the members of the public, these estimates are expressed in Publication 26 in terms of the risk of inducing fatal malignancies or serious hereditary ill health. These frequencies are compared with those of occupational fatalities in other industries or with accidental fatalities amongst the general public. The comparison between harm from radiation and from other agents in different industries is extended in ICRP-27 (on ''Problems Involved in Developing an Index of Harm'') in a review of the time lost through occupational diseases and non-fatal accidents, as well as from fatal diseases and accidents, so that the levels of safety achievable by the Commission's recommendations can be reviewed in the general perspective of occupational safety. (author)

Consequences of the new atomic bomb survivor dosimetry on radiation risk estimates

International Nuclear Information System (INIS)

Doerschel, B.

1990-01-01

The assessment of radiation risk includes the following steps: a) selection of biological data from epidemiological studies, b) adjustment of biological data to radiation doses, c) time projection of risk beyond the observation period. The life-time risk used by the ICRP since 1977 is mainly based on the epidemiological data for the survivors of Hiroshima and Nagasaki as well as on the linear dose-response and the absolute risk model. A re-evaluation of the life-time risk seems to be useful because since that time the observation period was further growing and better arguments for choosing a time projection model are available. On the other hand the revised dose can cause changes in the shape of the dose-response curves and of the RBE of neutrons. In the present paper the influence of these factors on the life-time risk will be investigated. (author)

Ionizing radiation and genetic risks

International Nuclear Information System (INIS)

Sankaranarayanan, K.; Wassom, J.S.

2005-01-01

Recent estimates of genetic risks from exposure of human populations to ionizing radiation are those presented in the 2001 report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). These estimates incorporate two important concepts, namely, the following: (1) most radiation-induced mutations are DNA deletions, often encompassing multiple genes, but only a small proportion of the induced deletions is compatible with offspring viability; and (2) the viability-compatible deletions induced in germ cells are more likely to manifest themselves as multi-system developmental anomalies rather than as single gene disorders. This paper: (a) pursues these concepts further in the light of knowledge of mechanisms of origin of deletions and other rearrangements from two fields of contemporary research: repair of radiation-induced DNA double-strand breaks (DSBs) in mammalian somatic cells and human molecular genetics; and (b) extends them to deletions induced in the germ cell stages of importance for radiation risk estimation, namely, stem cell spermatogonia in males and oocytes in females. DSB repair studies in somatic cells have elucidated the roles of two mechanistically distinct pathways, namely, homologous recombination repair (HRR) that utilizes extensive sequence homology and non-homologous end-joining (NHEJ) that requires little or no homology at the junctions. A third process, single-strand annealing (SSA), which utilizes short direct repeat sequences, is considered a variant of HRR. HRR is most efficient in late S and G 2 phases of the cell cycle and is a high fidelity mechanism. NHEJ operates in all cell cycle phases, but is especially important in G 1 . In the context of radiation-induced DSBs, NHEJ is error-prone. SSA is also an error-prone mechanism and its role is presumably similar to that of HRR. Studies in human molecular genetics have demonstrated that the occurrence of large deletions, duplications or other rearrangements

Ionizing radiation and genetic risks

Energy Technology Data Exchange (ETDEWEB)

Sankaranarayanan, K. [Department of Toxicogenetics, Leiden University Medical Centre, Sylvius Laboratories, Wassenaarseweg 72, 2333 AL Leiden (Netherlands)]. E-mail: sankaran@lumc.nl; Wassom, J.S. [YAHSGS, LLC, Richland, WA 99352 (United States); Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States)

2005-10-15

Recent estimates of genetic risks from exposure of human populations to ionizing radiation are those presented in the 2001 report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). These estimates incorporate two important concepts, namely, the following: (1) most radiation-induced mutations are DNA deletions, often encompassing multiple genes, but only a small proportion of the induced deletions is compatible with offspring viability; and (2) the viability-compatible deletions induced in germ cells are more likely to manifest themselves as multi-system developmental anomalies rather than as single gene disorders. This paper: (a) pursues these concepts further in the light of knowledge of mechanisms of origin of deletions and other rearrangements from two fields of contemporary research: repair of radiation-induced DNA double-strand breaks (DSBs) in mammalian somatic cells and human molecular genetics; and (b) extends them to deletions induced in the germ cell stages of importance for radiation risk estimation, namely, stem cell spermatogonia in males and oocytes in females. DSB repair studies in somatic cells have elucidated the roles of two mechanistically distinct pathways, namely, homologous recombination repair (HRR) that utilizes extensive sequence homology and non-homologous end-joining (NHEJ) that requires little or no homology at the junctions. A third process, single-strand annealing (SSA), which utilizes short direct repeat sequences, is considered a variant of HRR. HRR is most efficient in late S and G{sub 2} phases of the cell cycle and is a high fidelity mechanism. NHEJ operates in all cell cycle phases, but is especially important in G{sub 1}. In the context of radiation-induced DSBs, NHEJ is error-prone. SSA is also an error-prone mechanism and its role is presumably similar to that of HRR. Studies in human molecular genetics have demonstrated that the occurrence of large deletions, duplications or other

Fundamentals of risk/benefit analysis in radiation uses in preventive medicine

International Nuclear Information System (INIS)

Stieve, F.E.

1977-01-01

The term 'risk' stems from the insurance branch. It serves to estimate the probability of making statements about future events on the basis of events which have taken place. Risk estimations are increasingly being made in medicine, especially for determining the advantages and dangers brought to the population by preventive measures. The international radiation protection commission has, for some time, been expressing the dangers of ionising radiation in terms of risk and using these terms as basis for the dose limit values it determined for the professional and general population. This paper deals with possibilities of determining risks in preventive medicine. For doing this, acceptable risk values must be determined and risks resulting from diseases, esp. from those which were not recognized in time, must be compared with those resulting from the application of ionising radiation. (orig.) [de

An interim UK response to revised risk estimates

International Nuclear Information System (INIS)

Beaver, P.F.; Bines, W.P.

1992-01-01

This paper describes the legal framework in place when the revised risk estimates were announced by the International Commission for Radiological Protection (ICRP) in 1987 and how an addition to that framework enabled the revised risk estimates to be taken into account when making decisions about radiation protection practice both at plant and individual worker level. It is suggested that this a may be an early example of the use of a constraint applied generically. (author)

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

International Nuclear Information System (INIS)

Fabrikant, J.I.

1991-08-01

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

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

International Nuclear Information System (INIS)

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

2005-01-01

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

Radiation risks and benefits: politics and morality

International Nuclear Information System (INIS)

Maxey, M.N.

1983-01-01

The bioethical framework from which moral reasoning concerning nuclear technology has been derived is both seriously flawed and conceptually inadequate. The reasons are examined and are arranged in response to three questions. First, what is the status of alleged scientific evidence from which moral conclusions about the unacceptability of man-made radiation exposures are derived. Secondly, what criticisms of risk assessment reasoning are pertinent to ethical reflection. Finally, what revisions in an ethical framework are necessary if risk estimates of low-dose radiation exposure are to be conducted properly

Comments on mutagenesis risk estimation

International Nuclear Information System (INIS)

Russell, W.L.

1976-01-01

Several hypotheses and concepts have tended to oversimplify the problem of mutagenesis and can be misleading when used for genetic risk estimation. These include: the hypothesis that radiation-induced mutation frequency depends primarily on the DNA content per haploid genome, the extension of this concept to chemical mutagenesis, the view that, since DNA is DNA, mutational effects can be expected to be qualitatively similar in all organisms, the REC unit, and the view that mutation rates from chronic irradiation can be theoretically and accurately predicted from acute irradiation data. Therefore, direct determination of frequencies of transmitted mutations in mammals continues to be important for risk estimation, and the specific-locus method in mice is shown to be not as expensive as is commonly supposed for many of the chemical testing requirements

Theoretical vs. measured risk estimates for the external exposure to ionizing radiation pathway - a case study of a major industrial site

International Nuclear Information System (INIS)

Dundon, S.T.

1996-01-01

Two methods of estimating the risk to industrial receptors to ionizing radiation are presented here. The first method relies on the use of the U.S. Environmental Protection Agency (EPA) external exposure slope factor combined with default exposure parameters for industrial land uses. The second method employs measured exposure rate date and site-specific exposure durations combined with the BEIR V radiological risk coefficient to estimate occupational risk. The uncertainties in each method are described qualitatively. Site-specific information was available for the exposure duration and the exposure frequency as well as historic dosimetry information. Risk estimates were also generated for the current regulatory cleanup level (removal risks included) and for a no action scenario. The study showed that uncertainties for risks calculated using measured exposure rates and site-specific exposure parameters were much lower and defendable than using EPA slope factors combined with default exposure parameters. The findings call into question the use of a uniform cleanup standard for depleted uranium that does not account for site-specific land uses and relies on theoretical models rather than measured exposure rate information

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

Directory of Open Access Journals (Sweden)

Francis A Cucinotta

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

The communication of the radiation risk from CT in relation to its clinical benefit in the era of personalized medicine. Pt. 1. The radiation risk from CT

Energy Technology Data Exchange (ETDEWEB)

Westra, Sjirk J. [Massachusetts General Hospital, Division of Pediatric Radiology, Boston, MA (United States)

2014-10-15

The theory of radiation carcinogenesis has been debated for decades. Most estimates of the radiation risks from CT have been based on extrapolations from the lifespan follow-up study of atomic bomb survivors and on follow-up studies after therapeutic radiation, using the linear no-threshold theory. Based on this, many population-based projections of induction of future cancers by CT have been published that should not be used to estimate the risk to an individual because of their large margin of error. This has changed recently with the publication of three large international cohort follow-up studies, which link observed cancers to CT scans received in childhood. A fourth ongoing multi-country study in Europe is expected to have enough statistical power to address the limitations of the prior studies. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) report released in 2013 specifically addresses variability in response of the pediatric population exposed to ionizing radiation. Most authorities now conclude that there is enough evidence to link future cancers to the radiation exposure from a single CT scan in childhood but that cancer risk estimates for individuals must be based on the specifics of exposure, age at exposure and absorbed dose to certain tissues. Generalizations are not appropriate, and the communication of the CT risk to individuals should be conducted within the framework of personalized medicine. (orig.)

The stochastic risks of radioactive radiation - risk assessment, risk proportions, dose limits

International Nuclear Information System (INIS)

Lindackers, K.H.

1990-01-01

The latest data on the delayed injury to the a-bomb survivors of Hiroshima and Nagasaki reveal that the effects of radiation are more severe than was estimated in the past. However, the application of these data to small dose rate radiation exposure over longer periods of time leads to an overestimation of the actual risk. The future supersonic aviation schemes for altitudes within 20,000 m should include early personnel check-ups for assessment of the required protective measures. (orig./DG) [de

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

International Nuclear Information System (INIS)

Scott, B.R.

1998-01-01

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

Assessment of genetic risk for human exposure to radiation

International Nuclear Information System (INIS)

Sevcenko, V.A.; Rubanovic, A.V.

2002-01-01

Full text: The methodology of assessing the genetic risk of radiation exposure is based on the concept of 'hitting the target' in development of which N.V. Timofeeff-Ressovsky has played and important role. To predict genetic risk posed by irradiation, the U N Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has worked out direct and indirect methods of assessment, extrapolation, integral and palpitation criteria of risk analysis that together permit calculating the risk from human exposure on the basis of data obtained for mice. Based on the reports of UNSCEAR for the period from 1958 to 2001 the paper presents a retrospective analysis of the use of direct methods and the doubling dose method for quantitative determination of the genetic risk of human exposure expressed as different hereditary diseases. As early as 1962 UNSCEAR estimated the doubling dose (a dose causing as many mutations as those occurring spontaneously during one generation) at 1 Gy for cases of exposure to ionizing radiations with low LET at a low dose rate and this value was confirmed in the next UNSCEAR reports up to now. For cases of acute irradiation the doubling dose was estimated at 0,3-0,4 Gy for the period under review. The paper considers the evolution of the concepts of human natural hereditary variability which is a basis for assessing the risk of exposure by the doubling dose method. The level of human natural genetic variability per 1 000 000 newborns is estimated at 738 000 hereditary diseases including mendelian, chromosomal and multifactorial ones. The greatest difficulties in assessing the doubling dose value were found to occur in the case of multifactorial diseases the pheno typical expression of which depends on mutational events in polygenic systems and on numerous environmental factors. The introduction in calculations of the potential recoverability correction factor (RPCF) made it possible to assess the genetic risk taking into account this class of

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

International Nuclear Information System (INIS)

Krille, Lucian; Hammer, Gael P.; Merzenich, Hiltrud; Zeeb, Hajo

2010-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Moseeva, Maria B.; Azizova, Tamara V.; Grigoryeva, Evgenia S. [Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region (Russian Federation); Haylock, Richard [Public Health of England, London (United Kingdom)

2014-05-15

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

Review of the controversy on risks from low levels of radiation

International Nuclear Information System (INIS)

Higson, D.

2001-01-01

The need for regulation of low levels of radiation exposure, and the estimation of risks from such exposures, are based on the assumption that risk is proportional to dose without a threshold, the 'linear no-threshold (LNT) hypothesis'. This assumption is not supported by scientific data. There is no clear evidence of harm from low levels of exposure, up to at least 20 mSv (acute dose) or total dose rates of at least 50 mSv per year. Even allowing for reasonable extrapolation from radiation levels at which harmful effects have been observed, the LNT assumption should not be used to estimate risks from doses less than 100 mSv. Laboratory and epidemiological evidence, and evolutionary expectations of biological effects from low level radiation, suggest that beneficial health effects (sometimes called 'radiation hormesis') are at least as likely as harmful effects from such exposures. Controversy on this matter strikes at the basis of radiation protection practice

Mutation frequencies in male mice and the estimation of genetic hazards of radiation in men: (specific-locus mutations/dose-rate effect/doubling dose/risk estimation)

International Nuclear Information System (INIS)

Russell, W.L.; Kelly, E.M.

1982-01-01

Estimation of the genetic hazards of ionizing radiation in men is based largely on the frequency of transmitted specific-locus mutations induced in mouse spermatogonial stem cells at low radiation dose rates. The publication of new data on this subject has permitted a fresh review of all the information available. The data continue to show no discrepancy from the interpretation that, although mutation frequency decreases markedly as dose rate is decreased from 90 to 0.8 R/min (1 R = 2.6 X 10 -4 coulombs/kg) there seems to be no further change below 0.8 R/min over the range from that dose rate to 0.0007 R/min. Simple mathematical models are used to compute: (a) a maximum likelihood estimate of the induced mutation frequency at the low dose rates, and (b) a maximum likelihood estimate of the ratio of this to the mutation frequency at high dose rates in the range of 72 to 90 R/min. In the application of these results to the estimation of genetic hazards of radiation in man, the former value can be used to calculate a doubling dose - i.e., the dose of radiation that induces a mutation frequency equal to the spontaneous frequency. The doubling dose based on the low-dose-rate data compiled here is 110 R. The ratio of the mutation frequency at low dose rate to that at high dose rate is useful when it becomes necessary to extrapolate from experimental determinations, or from human data, at high dose rates to the expected risk at low dose rates. The ratio derived from the present analysis is 0.33

The impact of involved node, involved field and mantle field radiotherapy on estimated radiation doses and risk of late effects for pediatric patients with Hodgkin lymphoma

DEFF Research Database (Denmark)

Maraldo, M V; Jørgensen, M; Brodin, N P

2014-01-01

BACKGROUND: The use of radiotherapy (RT) is debated for pediatric patients with Hodgkin lymphoma (HL) due to the late effects of treatment. Radiation doses to the thyroid, heart, lungs, and breasts are compared with the extensive mantle field (MF), Involved Field RT(IFRT), Modified IFRT (m......IFRT), and Involved Node RT (INRT) and the risk of radiation-induced cardiovascular disease, secondary cancers, and the corresponding Life Years Lost (LYL) is estimated with each technique. PROCEDURE: INRT, mIFRT, IFRT, and MF plans (20 and 30 Gy) were simulated for 10 supradiaphragmatic, clinical stage I......–II classical HL patients lung, breast, and thyroid cancer with each technique were estimated. The estimated excess risks attributable to RT were based on HL series with long-term follow...

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

Science.gov (United States)

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

2016-09-01

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

Implications of radiation risk for practical dosimetry

International Nuclear Information System (INIS)

Dennis, J.A.

1984-01-01

Radiobiological experiments with animals and cells have led to an expectation that the risks of cancer and hereditary effects are reduced at low doses and low dose rates of low LET radiation. Risk estimates derived from human exposures at high doses and dose rates usually contain an allowance for low dose effects in comparison with high dose effects, but no allowance may have been made for low dose rate effects. Although there are reasons for thinking that leukaemia risks may possibly have been underestimated, the total cancer risk assumed by ICRP for occupational exposures is reasonably realistic. For practical dosimetry the primary dose concepts and limits have to be translated into secondary quantities that are capable of practical realisation and measurement, and which will provide a stable and robust system of metrology. If the ICRP risk assumptions are approximately correct, it is extremely unlikely that epidemiological studies of occupational exposures will detect the influence of radiation. Elaboration of dosimetry and dose recording for epidemiological purposes is therefore unjustified except possibly in relation to differences between high and low LET radiations. (author)

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

Science.gov (United States)

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...

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

International Nuclear Information System (INIS)

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

1988-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1988-08-01

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

Diagnostic radiation risks

Energy Technology Data Exchange (ETDEWEB)

Sherwood, T [Addenbrooke' s Hospital, Cambridge (UK)

1980-04-01

A brief discussion on diagnostic radiation risks is given. First some fundamental facts on the concepts and units of radiation measurement are clarified. Medical diagnostic radiation doses are also compared to the radiation doses received annually by man from natural background radiation. The controversy concerning the '10-day rule' in X-raying women of child-bearing age is discussed; it would appear that the risk of malformation in an unborn child due to X-radiation is very much less than the natural level of risk of malformation. The differences in the radiographic techniques and thus the different X-ray doses needed to make adequate X-ray images of different parts of the body are considered. The radiation burden of nuclear medicine investigations compared to X-ray procedures is also discussed. Finally, the problems of using volunteers in radiation research are aired.

Evaluating shielding effectiveness for reducing space radiation cancer risks

International Nuclear Information System (INIS)

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

2006-01-01

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 PDFs are used in significance tests for evaluating 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 PDFs. Competing mortality risks and functional correlations in radiation quality factor uncertainties are included in the calculations. We show that the cancer risk uncertainty, defined as the ratio of the upper value of 95% confidence interval (CI) to the point estimate is about 4-fold for lunar and Mars mission risk projections. For short-stay lunar missions ( 180d) or Mars missions, GCR risks may exceed radiation risk limits that are based on acceptable levels of risk. For example, the upper 95% CI 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 cannot be shown to significantly reduce risk compared to aluminum shielding based on a significance test that accounts for radiobiology uncertainties in GCR risk projection

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

International Nuclear Information System (INIS)

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

1982-02-01

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

Radiation exposure to examiners and patients during therapeutic ERCP: Dose optimisation and risk estimation

International Nuclear Information System (INIS)

Sulieman, A.; Kappas, K.; Theodorou, K.; Paroutoglou, G.; Kapatenakis, A.; Kapsoritakis, A.; Potamianos, S.; Vlychou, M.; Fezoulidis, I.

2008-01-01

Aim: This study intended to optimise the radiation dose during therapeutic ERCP, and to estimate the risk for examiners and patients, to compare the doses based on available data obtained by other researchers and reference levels recommended by international organizations, and to evaluate the technique applied in order to reduce patient and examiners doses. Materials and Methods: 153 patients were studied in two Gastroenterology Departments, (group A, 111; group B, 42). Thermoluminescent dosimeters (TLD) were used to measure the staff and patients entrance surface dose (ESD) at different body sites. Results: The mean ESD, exit and thyroid surface dose per procedure was estimated to be 68.75 mGy, 3.45 mGy and 0.67 mGy, respectively. The mean patient effective dose was 3.44 mSv, and the cancer risk per procedure was estimated to be 190 x10 -6 . The effective dose for the first, second and third examiner was 0.4 μSv, 0.2 μSv and 5.0 μSv, respectively. Conclusion: The patient dose can be optimized by the presence of two experienced examiners and reduction of radiographic images. The examiners should use a wrap around lead apron since the highest dose originating from the X-ray tube, is incident on their side and back. The current formulae, which exist, underestimate the effective dose to the examiners, when they are applied for ERCP procedures. For both patients and examiners, our results were up to 60% lower compared to the lowest values found in previous studies. (authors)

Estimation of radiation dose and risk to children undergoing cardiac catheterization for the treatment of a congenital heart disease using Monte Carlo simulations

Energy Technology Data Exchange (ETDEWEB)

Yakoumakis, Emmanuel; Kostopoulou, Helen; Dimitriadis, Anastastios; Georgiou, Evaggelos [University of Athens, Medical Physics Department, Medical School, Athens (Greece); Makri, Triantafilia [' Agia Sofia' Hospital, Medical Physics Unit, Athens (Greece); Tsalafoutas, Ioannis [Anticancer-Oncology Hospital of Athens ' Agios Savvas' , Medical Physics Department, Athens (Greece)

2013-03-15

Children diagnosed with congenital heart disease often undergo cardiac catheterization for their treatment, which involves the use of ionizing radiation and therefore a risk of radiation-induced cancer. The purpose of this study was to calculate the effective and equivalent organ doses (H{sub T}) in those children and estimate the risk of exposure-induced death. Fifty-three children were divided into three groups: atrial septal defect (ASD), ventricular septal defect (VSD) and patent ductus arteriosus (PDA). In all procedures, the exposure conditions and the dose-area product meters readings were recorded for each individual acquisition. Monte Carlo simulations were run using the PCXMC 2.0 code and mathematical phantoms simulating a child's anatomy. The H{sub T} values to all irradiated organs and the resulting E and risk of exposure-induced death values were calculated. The average dose-area product values were, respectively, 40 {+-} 12 Gy.cm{sup 2} for the ASD, 17.5 {+-} 0.7 Gy.cm{sup 2} for the VSD and 9.5 {+-} 1 Gy.cm{sup 2} for the PDA group. The average E values were 40 {+-} 12, 22 {+-} 2.5 and 17 {+-} 3.6 mSv for ASD, VSD and PDA groups, respectively. The respective estimated risk of exposure-induced death values per procedure were 0.109, 0.106 and 0.067%. Cardiac catheterizations in children involve a considerable risk for radiation-induced cancer that has to be further reduced. (orig.)

Conceptus radiation dose and risk from chest screen-film radiography

International Nuclear Information System (INIS)

Damilakis, John; Perisinakis, Kostas; Dimovasili, Evangelia; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Varveris, Haralambos

2003-01-01

The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d a ) was estimated for 51 women of childbearing age from chest CT examinations. The value of d a was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10 -3 mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d a estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is no need for

Conceptus radiation dose and risk from chest screen-film radiography.

Science.gov (United States)

Damilakis, John; Perisinakis, Kostas; Prassopoulos, Panos; Dimovasili, Evangelia; Varveris, Haralambos; Gourtsoyiannis, Nicholas

2003-02-01

The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d(a)) was estimated for 51 women of childbearing age from chest CT examinations. The value of d(a) was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10(-3) mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d(a) estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is no need for

Conceptus radiation dose and risk from chest screen-film radiography

Energy Technology Data Exchange (ETDEWEB)

Damilakis, John; Perisinakis, Kostas; Dimovasili, Evangelia [Department of Medical Physics, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece); Prassopoulos, Panos; Gourtsoyiannis, Nicholas [Department of Radiology, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece); Varveris, Haralambos [Department of Radiotherapy, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece)

2003-02-01

The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d{sub a}) was estimated for 51 women of childbearing age from chest CT examinations. The value of d{sub a} was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10{sup -3} mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d{sub a} estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is

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

Directory of Open Access Journals (Sweden)

Francis A Cucinotta

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

Radiation doses and risks from internal emitters

International Nuclear Information System (INIS)

Harrison, John; Day, Philip

2008-01-01

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

Radiation related cancer risk after ionization radiation exposure to the Bulgarian population

International Nuclear Information System (INIS)

Chobanova, N.; Vasilev, G.; Hadjieva, T.

2008-01-01

Average annual individual effective dose of natural radiation background (NRB) for the Bulgarian population is estimated to be 2.33 mSv.a -1 (from 1.60 to 3.06). NRB has been considered nearly constant in time, but during the 20th century the radiation above NRB has gradually increased. It was mainly caused by the medical X-ray and radionuclide diagnostics, radiation treatment, occupational radiation, global radioactive fallout, Chernobyl accident, exploitation of thermal power and nuclear power stations, etc. For the years 1950-2000 collective dose from NRB represents 965 000 man.Sv and radiation over NRB gives 1 042 800 man.Sv. Population risk following radiation exposure is estimated mainly on stochastic health effect by implementation of the so-called Linear non-threshold model (LNM) dose-effect. It postulates no dose threshold for radiation-induced health effects. Using different models, assumptions and assessments, authors have determined the contribution of lethal radiogenic cancer to Bulgarian spontaneous cancer rate to be from 3.7% to 20.6%. Numerous contradictions and concepts about the LNM still persist, because from statistical point of view, LNM can neither be proved nor rejected. (authors)

The need to estimate risks

International Nuclear Information System (INIS)

Pochin, E.E.

1980-01-01

In an increasing number of situations, it is becoming possible to obtain and compare numerical estimates of the biological risks involved in different alternative sources of action. In some cases these risks are similar in kind, as for example when the risk of including fatal cancer of the breast or stomach by x-ray screening of a population at risk, is compared with the risk of such cancers proving fatal if not detected by a screening programme. In other cases in which it is important to attempt a comparison, the risks are dissimilar in type, as when the safety of occupations involving exposure to radiation or chemical carcinogens is compared with that of occupations in which the major risks are from lung disease or from accidental injury and death. Similar problems of assessing the relative severity of unlike effects occur in any attempt to compare the total biological harm associated with a given output of electricity derived from different primary fuel sources, with its contributions both of occupation and of public harm. In none of these instances is the numerical frequency of harmful effects alone an adequate measure of total biological detriment, nor is such detriment the only factor which should influence decisions. Estimations of risk appear important however, since otherwise public health decisions are likely to be made on more arbitrary grounds, and public opinion will continue to be affected predominantly by the type rather than also by the size of risk. (author)

Terrestrial Gamma Radiation Exposure Measurement and Risk Estimates in the Environments of Major Industries In Ota, Nigeria

Directory of Open Access Journals (Sweden)

Abodunrin Oluwasayo Peter

2016-11-01

Full Text Available When fast estimates are required, the in-situ method is more appropriate as this allows for quick results; preventing further exposure of the public and permitting quick intervention. Measurements of the terrestrial gamma radiation exposure have been carried out in the environments of major industries in Ota using a portable survey meter. The motivation for this study resulted from the uncertainty in the general public opinion on the effect of the presence, and activities of some of these industries in their environment. Measurements were taken twice daily within the vicinity of each industry to determine the dose levels. The mean values obtained range from 0.11 – 1.80 µSv/h. These values are within the results obtained from normal background areas except for site number 10. Annual effective dose values range from 0.25 – 5.21 mSv with a mean value of 1.21 mSv. Routine activities in some of these environments may have contributed significantly to the ambient natural background radiation resulting in high values as obtained in some of these locations. The total risks disparately estimated for cancer and genetic effects resulting from the results obtained range from 0.17 x 10-4 – 3.80 x 10-4 with a mean value of 0.94 x 10-4. These levels are within the range of the average annual risk for accidental death for all industries.

Assessment of the radiation risk from diagnostic radiology

International Nuclear Information System (INIS)

Streffer, C.; Mueller, W.U.

1995-01-01

In any assessment of radiation risks from diagnostic radiology the main concern is the possible induction of cancer. It now appears to be beyond all doubt that ionizing rays invite the development of cancer in humans. The radiation doses encountered in diagnostic radiology generally vary from 1 to 50 mSv. For this dose range, no measured values are available to ascertain cancer risks from ionizing rays. The effects of such doses must therefore be extrapolated from higher dose levels under consideration of given dose-effect relationships. All relevant figures for diagnostic X-ray measures are therefore mathematically determined approximate values. The stochastic radiation risk following non-homogeneous radiation exposure is assessed on the basis of the effective dose. This dose was originally introduced to ascertain the risk from radioactive substances incorporated at the working place. A secondary intention was to trigger further developmental processes in radiation protection. Due to the difficulties previously outlined and the uncertainties surrounding the determination and assessment of the effective dose from diagnostic X-ray procedures, this dose should merely be used for technological refinements and comaprisons of examination procedures. It appears unreasonable that the effective doses determined for the individual examinations are summed up to obtain a collective effective dose and to multiply this with a risk factor so as to give an approximation of the resulting deaths from cancer. A reasonable alternative is to inform patients subjected to X-ray examinations about the associated radiation dose and to estimate form this the magnitude of the probable radiation risk. (orig./MG) [de

Development of cancer risk estimates from epidemiologic studies

International Nuclear Information System (INIS)

Webster, E.W.

1983-01-01

Radiation risk estimates may be made for an increase in mortality from, or for an increase in incidence of, particular types of disease. For both endpoints, two numerical systems of risk expression are used: the absolute risk system (usually the excess deaths or cases per million persons per year per rad), and the relative risk system (usually excess deaths or cases per year per rad expressed as a percentage of those normally expected). Risks may be calculated for specific age groups or for a general population. An alternative in both risk systems is the estimation of cumulative of lifetime risk rather than annual risk (e.g. in excess deaths per million per rad over a specified long period including the remainder of lifespan). The derivation of both absolute and relative risks is illustrated by examples. The effects on risk estimates of latent period, follow-up time, age at exposure and age standardization within dose groups are illustrated. The dependence of the projected cumulative (lifetime) risk on the adoption of a constant absolute risk or constant relative risk is noted. The use of life-table data in the adjustment of cumulative risk for normal mortality following single or annual doses is briefly discussed

Assessment of impact of urbanisation on background radiation exposure and human health risk estimation in Kuala Lumpur, Malaysia.

Science.gov (United States)

Sanusi, M S M; Ramli, A T; Hassan, W M S W; Lee, M H; Izham, A; Said, M N; Wagiran, H; Heryanshah, A

2017-07-01

Kuala Lumpur has been undergoing rapid urbanisation process, mainly in infrastructure development. The opening of new township and residential in former tin mining areas, particularly in the heavy mineral- or tin-bearing alluvial soil in Kuala Lumpur, is a contentious subject in land-use regulation. Construction practices, i.e. reclamation and dredging in these areas are potential to enhance the radioactivity levels of soil and subsequently, increase the existing background gamma radiation levels. This situation is worsened with the utilisation of tin tailings as construction materials apart from unavoidable soil pollutions due to naturally occurring radioactive materials in construction materials, e.g. granitic aggregate, cement and red clay brick. This study was conducted to assess the urbanisation impacts on background gamma radiation in Kuala Lumpur. The study found that the mean value of measured dose rate was 251±6nGyh -1 (156-392nGyh -1 ) and 4 times higher than the world average value. High radioactivity levels of 238 U (95±12Bqkg -1 ), 232 Th (191±23Bqkg -1 ,) and 40 K (727±130Bqkg -1 ) in soil were identified as the major source of high radiation exposure. Based on statistical ANOVA, t-test, and analyses of cumulative probability distribution, this study has statistically verified the dose enhancements in the background radiation. The effective dose was estimated to be 0.31±0.01mSvy -1 per man. The recommended ICRP reference level (1-20mSvy -1 ) is applicable to the involved existing exposure situation in this study. The estimated effective dose in this study is lower than the ICRP reference level and too low to cause deterministic radiation effects. Nevertheless based on estimations of lifetime radiation exposure risks, this study found that there was small probability for individual in Kuala Lumpur being diagnosed with cancer and dying of cancer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radiobiology in clinical radiation therapy: Long term risks - Carcinogenic, hereditary, and teratogenetic effects

International Nuclear Information System (INIS)

Brenner, David J.

1997-01-01

The long-term risks induced by radiation are of much concern to patients and clinicians alike. As an example, perceived radiation risks are frequently cited in a woman's decision to choose a radical mastectomy over lumpectomy + radiation. In consequence, the actual radiation risks are often considerably overstated, or unreasonably downplayed. In this lecture we will discuss just what is known about the long term risks following radiotherapy, both from the human experience and from the laboratory. We will discuss risks both to the patient and to radiotherapy personnel. A good deal is known about the carcinogenic effects of high and low doses of radiation, in large part thanks to the careful study of the survivors of the atomic bombing in Japan, as well as studies of individuals exposed to medical x rays. It is possible to make an estimate, which is probably good to within a factor of, perhaps, three to five, of the cancer risks faced by a patient of a particular age and sex who is going to undergo a particular radiotherapeutic regimen. It is also possible to make an estimate of the risks faced by radiotherapy and nursing staff exposed to low doses. Brachytherapy related risk estimates are likely to be somewhat more uncertain, due to the poorly known sparing effects of the low dose rates used; for the radiotherapy personnel in brachytherapy, because of the doses which can be received, the risks can be quite significant. A recent complication in external-beam radiotherapy is the advent of high-energy linacs, which can produce a significant fast neutron dose which, dose for dose, may be ten to fifty times more carcinogenic than gamma rays. Data relating to the risks of hereditary effects of radiation come almost entirely from laboratory experiments in animals. Studies involving several million mice form the basis of most of our current understanding of hereditary effects. The results of these studies indicate that radiation is a relatively inefficient mutagen. The

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

Science.gov (United States)

Chernov, Anatolii; Shabatura, Olexandr

2016-04-01

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

A perspective on the radiation protection problem and risk analysis for the nuclear era

International Nuclear Information System (INIS)

Vohra, K.G.

1977-01-01

The projected large scale use of nuclear energy and sources of ionizing radiations would involve the radiation exposure of larger numbers of occupational workers, individuals and groups in the population, and the population-at-large. There is an urgent need for projecting these exposures in a proper perspective, by comparing the associated risks with the risks from alternative energy sources, e.g. with those from the combustion products released by the fossil fuel plants. A comparative study of the risk of cancer mortality from radiations and airborne chemical pollutants has been presented. Radiation risk data is given in terms of cancer deaths per million per year for a given dose rate, based on the human experience. The lung cancer risks of the combined products of coal burning and a specific carcinogen benzo(a)pyrene have also been estimated, based on the extensive epidemiological data available for different countries. Using the dose-response data for radiation exposure at different annual dose rates, dose equivalents of chemical pollutants have been determined. Whereas the estimated risk for power reactor effluents is found to be only 1% of the risk at the ICRP dose limits for ionizing radiations, the current urban levels of benzo(a)pyrene (a product of fossil fuel combustion) are already large enough to present a 100 fold higher risk, equivalent to that of the ICRP dose limit for ionizing radiations. Comparison shows that percentage contributions to the overall risk are 0.06, 5.5 and 19.0 for nuclear power, fossil fuel pollutant benzo(a)pyrene (per ng/m 3 ) and total coal pollutants (per ton/capita consumption), respectively. Risk estimates for different stages of the nuclear fuel cycle, including the fast breeder reactor fuel cycle, are also presented

A new index of risks for lethal diseases by ionizing radiation

International Nuclear Information System (INIS)

Sato, Fumiaki; Higuti, Isao.

1979-01-01

Estimates of the somatic risk of radiation exposure have mainly been based on the incidence of fatal cancers. An improvement on the estimates of the risk will be made by taking mean ages at deaths into consideration in addition to the incidence of cancer. The authors report on an index of contribution of each cause of death to life shortening. The index is the sum of three terms. The first term indicates a contribution of change in incidence and the second term indicates that of changes in mean age at death from the cause of death in question. The last term is an interaction term of the two factors mentioned above. If a radiation exposure increases incidence of a cause of death and shortens the mean age at death from the cause of death, the index gives a large positive value. On the other hand, an increase in incidence of a late occurring cause of death will bring about a small positive or sometimes negative value for the index. The index proposed here will be promising in estimating risks by ionizing radiation. (author)

Revision of risk estimates and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

It has been apparent for some time that our estimates of the risks associated with exposure to ionizing radiation must be increased above those values reported by UNSCEAR in 1977 an dused by ICRP to form their present recommendations. NRPB foresaw some of these changes and introduced interim advice within the UK to restrict exposures of wordkers and members of the public to levels below the existing limits. Since that advice was given, UNSCEAR has produced a 1988 report reviewing human data to provide new estimates of risks associated with exposure at high doses and high doserates. These risk figures are up to 4 times higher than when UNSCEAR reported in 1977. In this paper, the reasons for the changes in the estimates of risk will be described and the current NRPB guidelines for risk factors for protection purposes will be presented. The implications of these new risk factors for the setting of dose limits will then be discussed. (Author). 10 refs.; 2 tabs

Projection of radiation-induced cancer risks across time and populations

International Nuclear Information System (INIS)

Muirhead, C.R.

1991-01-01

Various methods can be used to project the risks of radiation-induced cancer estimated in cohort studies beyond the period of follow-up and to other populations. The choice of risk projection model is reviewed based on data from studies such as those of the Japanese atomic bomb survivors and UK ankylosing spondylitis patients given X ray therapy. Risk estimates applicable to a UK population are calculated on the basis of various models, including those developed by the BEIR V Committee. It is emphasised that the continued follow-up of populations such as the Japanese atomic bomb survivors is of great importance in estimating lifetime risks. (author)

Estimation of lung cancer risk from environmental exposure to airborne plutonium from the Rocky Flats Plant

International Nuclear Information System (INIS)

Sutherland, J.V.

1983-01-01

A three-phase study was undertaken to (1) determine the nature of disagreement among scientists concerning risk of environmental release of plutonium, (2) develop an analytic procedure for determining risk based on clearly stated principles defensible by reference to the literature, and (3) develop estimates of radiation dose to the lung from exposure to plutonium in ambient air for the purpose of evaluating risk to an individual with a specified age and smoking history. Eleven epidemiologists, biostatisticians and radiation scientists participated in Phase I of the study. It was shown that no clearly stated analytical principles for risk estimation were in common use, resulting in widely divergent risk estimates. Five of these disagreeing scientists in Phase I (including all cancer epidemiologists in the Denver metropolitan area) were chosen for Phase II of the study. A single analytic procedure was developed which was unanimously agreed upon. This procedure was dependent on the estimate of dose to the lung from ambient air levels of Rocky Flats plutonium. In Phase III of the study, a panel of four radiation scientists developed a procedure for estimation of dose to the lung from chronic exposure to plutonium ambient air levels. Results from all phases of the study were used to develop a method for estimation of relative risk of lung cancer for an individual, given plutonium dose to the lung, age, smoking history and other radiation exposure

Comparison of additive (absolute) risk projection models and multiplicative (relative) risk projection models in estimating radiation-induced lifetime cancer risk

International Nuclear Information System (INIS)

Kai, Michiaki; Kusama, Tomoko

1990-01-01

Lifetime cancer risk estimates depend on risk projection models. While the increasing lengths of follow-up observation periods of atomic bomb survivors in Hiroshima and Nagasaki bring about changes in cancer risk estimates, the validity of the two risk projection models, the additive risk projection model (AR) and multiplicative risk projection model (MR), comes into question. This paper compares the lifetime risk or loss of life-expectancy between the two projection models on the basis of BEIR-III report or recently published RERF report. With Japanese cancer statistics the estimates of MR were greater than those of AR, but a reversal of these results was seen when the cancer hazard function for India was used. When we investigated the validity of the two projection models using epidemiological human data and animal data, the results suggested that MR was superior to AR with respect to temporal change, but there was little evidence to support its validity. (author)

Radiation protection standards: A practical exercise in risk assessment

Energy Technology Data Exchange (ETDEWEB)

Clarke, Roger H [National Radiological Protection Board (United Kingdom)

1992-07-01

Within 12 months of the discovery of x-rays in 1895, it was reported that large doses of radiation were harmful to living human tissues. The first radiation protection standards were set to avoid the early effects of acute irradiation. By the 1950s, evidence was mounting for late somatic effects - mainly a small excess of cancers - in irradiated populations. In the late 1980's, sufficient human epidemiological data had been accumulated to allow a comprehensive assessment of carcinogenic radiation risks following the delivery of moderately high doses. Workers and the public are exposed to lower doses and dose-rates than the groups from whom good data are available so that risks have had to be estimated for protection purposes. However, in the 1990s, some confirmation of these risk factors has been derived occupationally exposed populations. If an estimate is made of the risk per unit dose, then in order to set dose limits, an unacceptable level of risk must be established for both workers and the public. There has been and continues to be a debate about the definitions of 'acceptable' and 'tolerable' and the attributing of numerical values to these definitions. This paper discusses the issues involved in the quantification of these terms and their application to setting dose limits on risk grounds. Conclusions are drawn about the present protection standards and the application of the methods to other fields of risk assessment. (author)

Radiation protection standards: A practical exercise in risk assessment

International Nuclear Information System (INIS)

Clarke, Roger H.

1992-01-01

Within 12 months of the discovery of x-rays in 1895, it was reported that large doses of radiation were harmful to living human tissues. The first radiation protection standards were set to avoid the early effects of acute irradiation. By the 1950s, evidence was mounting for late somatic effects - mainly a small excess of cancers - in irradiated populations. In the late 1980's, sufficient human epidemiological data had been accumulated to allow a comprehensive assessment of carcinogenic radiation risks following the delivery of moderately high doses. Workers and the public are exposed to lower doses and dose-rates than the groups from whom good data are available so that risks have had to be estimated for protection purposes. However, in the 1990s, some confirmation of these risk factors has been derived occupationally exposed populations. If an estimate is made of the risk per unit dose, then in order to set dose limits, an unacceptable level of risk must be established for both workers and the public. There has been and continues to be a debate about the definitions of 'acceptable' and 'tolerable' and the attributing of numerical values to these definitions. This paper discusses the issues involved in the quantification of these terms and their application to setting dose limits on risk grounds. Conclusions are drawn about the present protection standards and the application of the methods to other fields of risk assessment. (author)

Knowledge of medical imaging radiation dose and risk among doctors

International Nuclear Information System (INIS)

Brown, Nicholas; Jones, Lee

2013-01-01

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

Sensitivity of APSIM/ORYZA model due to estimation errors in solar radiation

Directory of Open Access Journals (Sweden)

Alexandre Bryan Heinemann

2012-01-01

Full Text Available Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, biomass, leaf area (LAI and total accumulated solar radiation (SRA during the crop cycle. The accuracy of the 5 models for estimated daily solar radiation was similar, and it was not substantially different among sites. For water limited environments (no irrigation, crop model outputs yield, biomass and LAI was not sensitive for the uncertainties in radiation models studied here.

From 'Image Gently' to image intelligently: a personalized perspective on diagnostic radiation risk

International Nuclear Information System (INIS)

Guillerman, R.P.

2014-01-01

The risk of ionizing radiation from diagnostic imaging has been a popular topic in the radiology literature and lay press. Communicating the magnitude of risk to patients and caregivers is problematic because of the uncertainty in estimates derived principally from epidemiological studies of large populations, and alternative approaches are needed to provide a scientific basis for personalized risk estimates. The underlying patient disease and life expectancy greatly influence risk projections. Research into the biological mechanisms of radiation-induced DNA damage and repair challenges the linear no-threshold dose-response assumption and reveals that individuals vary in sensitivity to radiation. Studies of decision-making psychology show that individuals are highly susceptible to irrational biases when judging risks. Truly informed medical decision-making that respects patient autonomy requires appropriate framing of radiation risks in perspective with other risks and with the benefits of imaging. To follow the principles of personalized medicine and treat patients according to their specific phenotypic and personality profiles, diagnostic imaging should optimally be tailored not only to patient size, body region and clinical indication, but also to underlying disease conditions, radio-sensitivity and risk perception and preferences that vary among individuals. (orig.)

Radiation dose estimates for radiopharmaceuticals

International Nuclear Information System (INIS)

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

1996-04-01

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

Radiation quality and effective dose equivalent of alpha particles from radon decay products indoors: uncertainties in risk estimation

Energy Technology Data Exchange (ETDEWEB)

Al-Affan, I.A. (Velindre Hospital, Whitchurch, Cardiff (United Kingdom))

1994-01-01

In order to make a better estimate of cancer risk due to radon the radiation quality of alpha particles emitted from the element and its daughters has been re-assessed. In particular, uncertainties in all components involved in the calculations of the effective dose E, have been investigated. This has been done in the light of the recent draft report of the ICRU on quantities and units for use in radiation protection (Allisy et al (1991) ICRU NEWS 2). On the assumption of an indoor radon concentration of 30 Bq.m[sup -3], microdose spectra have been calculated for alpha particles hitting lung cells at different depths. Then the mean quality factor Q-bar in the lung, dose equivalent H[sub T] to the lung and the effective dose have been calculated. A comparison between lung cancer risk from radon and that arising from diagnostic X rays to the chest is made. A suggestion to make the lung weighting factor w[sub T] a function of the fraction of lung cells hit is discussed. (Author).

[Regulatory radiation risks' for the population and natural objects within the Semipalatinsk Test Site].

Science.gov (United States)

Spiridonov, S I; Teten'kin, V L; Mukusheva, M K; Solomatin, V M

2008-01-01

Advisability of using risks as indicators for estimating radiation impacts on environmental objects and humans has been jusified. Results are presented from identification of dose burdens distribution to various cohorts of the population living within the Semipalatinsk Test Site (STS) and consuming contaminated farm products. Parameters of dose burden distributions are estimated for areas of livestock grazing and the most contaminated sectors within these areas. Dose distributions to meadow plants for the above areas have been found. Regulatory radiation risks for the STS population and meadow ecosystem components have been calculated. Based on the parameters estimated, levels of radiation exposure of the population and herbaceous plants have been compared.

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

Science.gov (United States)

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.

Assessment of radiation-induced cancer risks from the Chernobyl fallout in Finland

Energy Technology Data Exchange (ETDEWEB)

Servomaa, A; Komppa, T; Suomela, M [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

1997-09-01

Application of detailed radiation risk models to populations affected by radiation doses from the Chernobyl fallout allows forecasting and estimation of the consequences of the accident in countries far from the place of the accident, and comparison of the model estimates with epidemiological observations in low-dose conditions among large populations. 14 refs, 11 figs, 1 tab.

Assessment of radiation-induced cancer risks from the Chernobyl fallout in Finland

International Nuclear Information System (INIS)

Servomaa, A.; Komppa, T.; Suomela, M.

1997-01-01

Application of detailed radiation risk models to populations affected by radiation doses from the Chernobyl fallout allows forecasting and estimation of the consequences of the accident in countries far from the place of the accident, and comparison of the model estimates with epidemiological observations in low-dose conditions among large populations. 14 refs, 11 figs, 1 tab

Solar constant values for estimating solar radiation

International Nuclear Information System (INIS)

Li, Huashan; Lian, Yongwang; Wang, Xianlong; Ma, Weibin; Zhao, Liang

2011-01-01

There are many solar constant values given and adopted by researchers, leading to confusion in estimating solar radiation. In this study, some solar constant values collected from literature for estimating solar radiation with the Angstroem-Prescott correlation are tested in China using the measured data between 1971 and 2000. According to the ranking method based on the t-statistic, a strategy to select the best solar constant value for estimating the monthly average daily global solar radiation with the Angstroem-Prescott correlation is proposed. -- Research highlights: → The effect of the solar constant on estimating solar radiation is investigated. → The investigation covers a diverse range of climate and geography in China. → A strategy to select the best solar constant for estimating radiation is proposed.

Radiation risk index for pediatric CT. A patient-derived metric

International Nuclear Information System (INIS)

Samei, Ehsan; Tian, Xiaoyu; Paul Segars, W.; Frush, Donald P.

2017-01-01

There is a benefit in characterizing radiation-induced cancer risk in pediatric chest and abdominopelvic CT: a singular metric that represents the whole-body radiation burden while also accounting for age, gender and organ sensitivity. To compute an index of radiation risk for pediatric chest and abdominopelvic CT. Using a protocol approved by our institutional review board, 42 pediatric patients (age: 0-16 years, weight: 2-80 kg) were modeled into virtual whole-body anatomical models. Organ doses were estimated for clinical chest and abdominopelvic CT examinations of the patients using validated Monte Carlo simulations of two major scanner models. Using age-, size- and gender-specific organ risk coefficients, the values were converted to normalized effective dose (by dose length product) (denoted as the k factor) and a normalized risk index (denoted as the q factor). An analysis was performed to determine how these factors are correlated with patient age and size for both males and females to provide a strategy to better characterize individualized risk. The k factor was found to be exponentially correlated with the average patient diameter. For both genders, the q factor also exhibited an exponential relationship with both the average patient diameter and with patient age. For both factors, the differences between the scanner models were less than 8%. The study defines a whole-body radiation risk index for chest and abdominopelvic CT imaging, that incorporates individual estimated organ dose values, organ radiation sensitivity, patient size, exposure age and patient gender. This indexing metrology enables the assessment and potential improvement of chest and abdominopelvic CT performance through surveillance of practice dose profiles across patients and may afford improved informed communication. (orig.)

Radiation risk index for pediatric CT. A patient-derived metric

Energy Technology Data Exchange (ETDEWEB)

Samei, Ehsan [Duke University Medical Center, Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States); Duke University Medical Center, Department of Biomedical Engineering, Electrical and Computer Engineering, Durham, NC (United States); Duke University Medical Center, Medical Physics Graduate Program, Durham, NC (United States); Tian, Xiaoyu [Duke University Medical Center, Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States); Paul Segars, W. [Duke University Medical Center, Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States); Duke University Medical Center, Medical Physics Graduate Program, Durham, NC (United States); Frush, Donald P. [Duke University Medical Center, Medical Physics Graduate Program, Durham, NC (United States); Duke University Medical Center, Division of Pediatric Radiology, Department of Radiology, Durham, NC (United States)

2017-12-15

There is a benefit in characterizing radiation-induced cancer risk in pediatric chest and abdominopelvic CT: a singular metric that represents the whole-body radiation burden while also accounting for age, gender and organ sensitivity. To compute an index of radiation risk for pediatric chest and abdominopelvic CT. Using a protocol approved by our institutional review board, 42 pediatric patients (age: 0-16 years, weight: 2-80 kg) were modeled into virtual whole-body anatomical models. Organ doses were estimated for clinical chest and abdominopelvic CT examinations of the patients using validated Monte Carlo simulations of two major scanner models. Using age-, size- and gender-specific organ risk coefficients, the values were converted to normalized effective dose (by dose length product) (denoted as the k factor) and a normalized risk index (denoted as the q factor). An analysis was performed to determine how these factors are correlated with patient age and size for both males and females to provide a strategy to better characterize individualized risk. The k factor was found to be exponentially correlated with the average patient diameter. For both genders, the q factor also exhibited an exponential relationship with both the average patient diameter and with patient age. For both factors, the differences between the scanner models were less than 8%. The study defines a whole-body radiation risk index for chest and abdominopelvic CT imaging, that incorporates individual estimated organ dose values, organ radiation sensitivity, patient size, exposure age and patient gender. This indexing metrology enables the assessment and potential improvement of chest and abdominopelvic CT performance through surveillance of practice dose profiles across patients and may afford improved informed communication. (orig.)

Radiation carcinogenesis

International Nuclear Information System (INIS)

Fry, R.J.M.

1976-01-01

The risk of iatrogenic tumors with radiation therapy is so outweighed by the benefit of cure that estimates of risk have not been considered necessary. However, with the introduction of chemotherapy, combined therapy, and particle radiation therapy, the comparative risks should be examined. In the case of radiation, total dose, fractionation, dose rate, dose distribution, and radiation quality should be considered in the estimation of risk. The biological factors that must be considered include incidence of tumors, latent period, degree of malignancy, and multiplicity of tumors. The risk of radiation induction of tumors is influenced by the genotype, sex, and age of the patient, the tissues that will be exposed, and previous therapy. With chemotherapy the number of cells at risk is usually markedly higher than with radiation therapy. Clearly the problem of the estimation of comparative risks is complex. This paper presents the current views on the comparative risks and the importance of the various factors that influence the estimation of risk

The impact of involved node, involved field and mantle field radiotherapy on estimated radiation doses and risk of late effects for pediatric patients with Hodgkin lymphoma

DEFF Research Database (Denmark)

Maraldo, M. V.; Jorgensen, M.; Brodin, N. P.

2014-01-01

–II classical HL patients 4 x 2 plans for each patient. The lifetime excess risks of cardiac morbidity, cardiac mortality, lung, breast, and thyroid cancer with each technique were estimated. The estimated excess risks attributable to RT were based on HL series with long-term follow......IFRT), and Involved Node RT (INRT) and the risk of radiation-induced cardiovascular disease, secondary cancers, and the corresponding Life Years Lost (LYL) is estimated with each technique. PROCEDURE: INRT, mIFRT, IFRT, and MF plans (20 and 30 Gy) were simulated for 10 supradiaphragmatic, clinical stage I...... to the heart, lungs, breasts, and thyroid compared to past,extended fields, even for patients with mediastinal disease. This translated into a significantly reduced estimated risk of cardiovascular disease, secondary cancers, and LYL. CONCLUSIONS: Involved Node Radiotherapy should be considered for pediatric...

Radiation and risk

International Nuclear Information System (INIS)

Jacobi, W.

1983-01-01

From the beginnings of the peaceful utilization of nuclear energy, the principles of prevention and optimization have greatly limited the emission of radioactive substances. In this way, the radiation exposure associated with emissions from nuclear power plants during normal operation has been kept low compared with natural radiation exposure and its variance. This also applies to the local public in the vicinities of such plants. The present health hazard to the public arising from ionizing radiation is only a small fraction of the man-made risk to which the public is exposed in this country. This is also due to the fact that radiation protection employs the principle of prevention, which has been laid down in legal regulations. In this respect, the concepts and criteria developed in radiation protection for evaluation, limitation and optimization may be useful examples to other areas of safety at work and environmental protection. The acceptance of nuclear power is decisively influenced by the remaining residual risk of accidents. Extremely careful inspection and supervision of the technical safety of such plants is indispensable to prevent major accidents. The German Risk Study for Nuclear Power Plants has made an important contribution to this end. It is being continued. However, risk research must always be accompanied by risk comparison to allow numerical risk data to be evaluated properly and important features to be distinguished from unimportant ones. (orig.) [de

National Chernobyl registry of Russia: Radiation risks analysis

Energy Technology Data Exchange (ETDEWEB)

Ivanov, V K; Tsyb, A F [Medical Radiological Research Center (RAMS), Obninsk (Russian Federation)

1997-09-01

Ten years have elapsed after the Chernobyl accident. The problem concerning the estimation of the total integral damage to life and health of people exposed to radiation remains very complicated. A negative influence of the Chernobyl included a spectrum of factors which may reinforce each other. In particular, to date there are no theoretical models or practical recommendations on integral estimating the contribution of social and psycho-emotional factors to the risks of diseases due to radiological accidents. On the other hand, for maximum effective rehabilitation of suffered people the ranging and impartial determination of contribution both of proper radiation and non-radiation components of influence are needed. Therefore, continuation of long-standing investigations is of great practical importance to diminish health consequences of the accident. 5 refs, 7 figs, 4 tabs.

National Chernobyl registry of Russia: Radiation risks analysis

International Nuclear Information System (INIS)

Ivanov, V.K.; Tsyb, A.F.

1997-01-01

Ten years have elapsed after the Chernobyl accident. The problem concerning the estimation of the total integral damage to life and health of people exposed to radiation remains very complicated. A negative influence of the Chernobyl included a spectrum of factors which may reinforce each other. In particular, to date there are no theoretical models or practical recommendations on integral estimating the contribution of social and psycho-emotional factors to the risks of diseases due to radiological accidents. On the other hand, for maximum effective rehabilitation of suffered people the ranging and impartial determination of contribution both of proper radiation and non-radiation components of influence are needed. Therefore, continuation of long-standing investigations is of great practical importance to diminish health consequences of the accident. 5 refs, 7 figs, 4 tabs

Health effects of low-level ionising radiation: biological basis for risk assessment

International Nuclear Information System (INIS)

Upton, A.C.

1987-01-01

The biological basis for risk assessment is discussed. The risks of carcinogenic effects, teratogenic effects, and genetic (heritable) effects are estimated to vary in proportion with the dose of radiation in the low-dose domain; however, the risks also appear to vary with the LET of the radiation, age at the time of irradiation, and other variables. Although the data suffice to place the risks in perspective with other hazards of modern life, further research to refine the reliability of the risk assessment is called for. (author)

Ionization radiations - basis, risks and benefits

International Nuclear Information System (INIS)

Bodart, F.

1991-01-01

An attempt is made to discuss the use of ionizing radiations in an impartial way. Ionizing radiation is potentially harmfull; excessive doses have a devastating effect on living cells. However, there is no direct, conclusive evidence of human disability, either in the form of cancer or genetic anomalies, arising as a consequence of low-level doses of x- or gamma-rays of about 0.01 Gray (1 rad) the entire dose range involved in medical radiography or in nuclear industry. Statements appearing in the press that a certain number of excess cancers will be produced are estimates, based maybe on plausible assumptions, but estimates nevertheless; they are not measured quantities or established facts. A balanced view of radiation must include appreciation of the substantial benefits which result from their use in both medicine and industry. The risks are small and hard to demonstrate, and it is instructive to make a comparison with the other hazards occuring continually in an industrialized society, such as driving a motorcar or smoking cigarettes. (Author)

Radiation exposures: risks and realities

International Nuclear Information System (INIS)

Ganesh, G.

2010-01-01

Discovery of radioactivity in 1869 by Henry Becquerel and artificial radioactivity by Irene Curie in 1934 led to the development of nuclear field and nuclear materials in 20th century. They are widely used for man-kind across the globe in electricity production, carbon dating, treatment and diagnosis of diseases etc. While deriving benefits and utilizing nuclear resources for the benefit of man-kind, it is inevitable that exposure to radiation can not be avoided. Radiation exists all around us either natural or man-made which can not be totally eliminated or avoided. Radiation exposures from natural background contribute 2.4 to 3.6 mSv in a year. Radiation exposures incurred by a member of public due to nuclear industries constitute less than one hundredth of annual dose due to natural background. Hence it is important to understand the risk posed by radiation and comparison of radiation risk with various risks arising due to other sources. Studies have indicated that risks due to environmental pollution, cigarette smoking, alcohol consumption, heart diseases are far higher in magnitude compared to radiation risks from man made sources. This paper brings about the details and awareness regarding radiation exposures, radiation risk, various risks associated with other industries and benefits of radiation exposures. (author)

Issues raised in the limitation, control and measurement of radiation risks

International Nuclear Information System (INIS)

Dennis, J.A.

1989-01-01

Over the past few years a consistent set of quantities for ionising radiation measurements in radiological protection have been defined. The efforts being made by those concerned with radiation dosimetry to ensure the universal adoption and use of these quantities are now threatened by further developments in risk concepts. The most serious threats arise from changed perceptions about the quality factors appropriate for different radiations due to improved biological information about relative biological effectiveness, and the increased importance to be given to the cancer risk estimates derived from the Hiroshima and Nagasaki survivors following the revised dose estimates. A change in the basis of quality factor specification will require careful consideration if it is not to produce further problems in obtaining agreement on the conceptual basis for radiological protection metrology. The change is primarily for adoption in the calculation of the risk quantity, effective dose equivalent. Some of the possible options for taking account of the change in regard to the measurement quantities are examined. (author)

Risk of solid cancer in low dose-rate radiation epidemiological studies and the dose-rate effectiveness factor.

Science.gov (United States)

Shore, Roy; Walsh, Linda; Azizova, Tamara; Rühm, Werner

2017-10-01

Estimated radiation risks used for radiation protection purposes have been based primarily on the Life Span Study (LSS) of atomic bomb survivors who received brief exposures at high dose rates, many with high doses. Information is needed regarding radiation risks from low dose-rate (LDR) exposures to low linear-energy-transfer (low-LET) radiation. We conducted a meta-analysis of LDR epidemiologic studies that provide dose-response estimates of total solid cancer risk in adulthood in comparison to corresponding LSS risks, in order to estimate a dose rate effectiveness factor (DREF). We identified 22 LDR studies with dose-response risk estimates for solid cancer after minimizing information overlap. For each study, a parallel risk estimate was derived from the LSS risk model using matching values for sex, mean ages at first exposure and attained age, targeted cancer types, and accounting for type of dosimetric assessment. For each LDR study, a ratio of the excess relative risk per Gy (ERR Gy -1 ) to the matching LSS ERR risk estimate (LDR/LSS) was calculated, and a meta-analysis of the risk ratios was conducted. The reciprocal of the resultant risk ratio provided an estimate of the DREF. The meta-analysis showed a LDR/LSS risk ratio of 0.36 (95% confidence interval [CI] 0.14, 0.57) for the 19 studies of solid cancer mortality and 0.33 (95% CI 0.13, 0.54) when three cohorts with only incidence data also were added, implying a DREF with values around 3, but statistically compatible with 2. However, the analyses were highly dominated by the Mayak worker study. When the Mayak study was excluded the LDR/LSS risk ratios increased: 1.12 (95% CI 0.40, 1.84) for mortality and 0.54 (95% CI 0.09, 0.99) for mortality + incidence, implying a lower DREF in the range of 1-2. Meta-analyses that included only cohorts in which the mean dose was LDR data provide direct evidence regarding risk from exposures at low dose rates as an important complement to the LSS risk estimates used

Total Risk Management for Low Dose Radiation Exposures

International Nuclear Information System (INIS)

Simic, Z.; Mikulicic, V.; Sterc, D.

2012-01-01

health. This view is supported with numerous evidences, and explained with beneficial effects from the increased activity of immune system activated with small radiation exposures. Finally, theory in between is that small doses are less than linearly proportionally harmful and that they are presenting a much smaller risks than according to the LNT. This view is derived from the use of different evidences. Difficulties to find one single theory about effects of small radiation doses are related to existence of huge variability and uncertainty in the evidence data. This is very hard experimental and theoretical problem. It will require lots of additional research to reduce these uncertainties and find final theory. This might be too late for the number of people affected in different ways with current single most conservative LNT approach. The problem with the conservative LNT regulatory approach is resulting in enormous additional costs of nuclear energy and medical applications. Which is reasonable and acceptable during the regular operation when source is high and concentrated. But, this becomes unreasonable huge economic burden after accidents and for cleanups with nuclear facilities. Similar problem arises with restriction of medical examinations and treatments based on over conservative risk estimate. Special circumstances are with evacuated people from contaminated areas where they are on the one side saved from small radiation exposures, and on the other side exposed to years of life away from their home and with numerous direct and indirect additional risks (i.e., stress, social problems, etc.). It seems reasonable that some alternative (total) risk management approach might be much more suitable for this situation. Evacuation of people from contaminated area with small doses sources should not be done when that induces larger risks from even what is expected from radiation based on LNT. Similar total risk management could be also applied for with medical

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

International Nuclear Information System (INIS)

Wakeford, Richard

2009-01-01

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

Estimating shortwave solar radiation using net radiation and meteorological measurements

Science.gov (United States)

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

NASA Space Radiation Risk Project: Overview and Recent Results

Science.gov (United States)

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.;

Consolidating Risk Estimates for Radiation-Induced Complications in Individual Patient: Late Rectal Toxicity

Energy Technology Data Exchange (ETDEWEB)

Prior, Phillip; Devisetty, Kiran [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Tarima, Sergey S. [Division of Biostatistics, Institute for Health and Society, Medical College of Wisconsin, Milwaukee, WI (United States); Lawton, Colleen A.F. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Semenenko, Vladimir A., E-mail: vsemenenko@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)

2012-05-01

Purpose: To test the feasibility of a new approach to synthesize published normal tissue complication data using late rectal toxicity in prostate cancer as an example. Methods and Materials: A data survey was performed to identify the published reports on the dose-response relationships for late rectal toxicity. The risk estimates for Grade 1 or greater, Grade 2 or greater, and Grade 3 or greater toxicity were obtained for a test cohort of patients treated at our institution. The influence of the potential factors that might have affected the reported toxicity levels was investigated. The studies that did not conform to the general data trends were excluded, and single, combined risk estimates were derived for each patient and toxicity level. Results: A total of 21 studies of nonoverlapping patient populations were identified. Three studies provided dose-response models for more than one level of toxicity. Of these 21 studies, 6, 14, and 5 were used to derive the initial risk estimates for Grade 1, 2, and 3 or greater toxicity, respectively. A comparison of risk estimates between the studies reporting rectal bleeding and rectal toxicity (bleeding plus other symptoms) or between studies with follow-up <36 months and {>=}36 months did not reveal significant differences (p {>=} .29 for all comparisons). After excluding three reports that did not conform to the general data trends, the combined risk estimates were derived from 5 reports (647 patients), 11 reports (3,369 patients), and 5 reports (1,330 patients) for Grade 1, 2, and 3 or greater toxicity, respectively. Conclusions: The proposed approach is feasible and allows for more systematic use of published dose-response data to estimate the complication risks for the individual patient.

Consolidating Risk Estimates for Radiation-Induced Complications in Individual Patient: Late Rectal Toxicity

International Nuclear Information System (INIS)

Prior, Phillip; Devisetty, Kiran; Tarima, Sergey S.; Lawton, Colleen A.F.; Semenenko, Vladimir A.

2012-01-01

Purpose: To test the feasibility of a new approach to synthesize published normal tissue complication data using late rectal toxicity in prostate cancer as an example. Methods and Materials: A data survey was performed to identify the published reports on the dose–response relationships for late rectal toxicity. The risk estimates for Grade 1 or greater, Grade 2 or greater, and Grade 3 or greater toxicity were obtained for a test cohort of patients treated at our institution. The influence of the potential factors that might have affected the reported toxicity levels was investigated. The studies that did not conform to the general data trends were excluded, and single, combined risk estimates were derived for each patient and toxicity level. Results: A total of 21 studies of nonoverlapping patient populations were identified. Three studies provided dose–response models for more than one level of toxicity. Of these 21 studies, 6, 14, and 5 were used to derive the initial risk estimates for Grade 1, 2, and 3 or greater toxicity, respectively. A comparison of risk estimates between the studies reporting rectal bleeding and rectal toxicity (bleeding plus other symptoms) or between studies with follow-up <36 months and ≥36 months did not reveal significant differences (p ≥ .29 for all comparisons). After excluding three reports that did not conform to the general data trends, the combined risk estimates were derived from 5 reports (647 patients), 11 reports (3,369 patients), and 5 reports (1,330 patients) for Grade 1, 2, and 3 or greater toxicity, respectively. Conclusions: The proposed approach is feasible and allows for more systematic use of published dose–response data to estimate the complication risks for the individual patient.

Knowledge of medical imaging radiation dose and risk among doctors.

Science.gov (United States)

Brown, Nicholas; Jones, Lee

2013-02-01

The growth of computed tomography (CT) and nuclear medicine (NM) scans has revolutionised healthcare but also greatly increased population radiation doses. Overuse of diagnostic radiation is becoming a feature of medical practice, leading to possible unnecessary radiation exposures and lifetime-risks of developing cancer. Doctors across all medical specialties and experience levels were surveyed to determine their knowledge of radiation doses and potential risks associated with some diagnostic imaging. A survey relating to knowledge and understanding of medical imaging radiation was distributed to doctors at 14 major Queensland public hospitals, as well as fellows and trainees in radiology, emergency medicine and general practice. From 608 valid responses, only 17.3% correctly estimated the radiation dose from CT scans and almost 1 in 10 incorrectly believed that CT radiation is not associated with any increased lifetime risk of developing cancer. There is a strong inverse relationship between a clinician's experience and their knowledge of CT radiation dose and risks, even among radiologists. More than a third (35.7%) of doctors incorrectly believed that typical NM imaging either does not use ionising radiation or emits doses equal to or less than a standard chest radiograph. Knowledge of CT and NM radiation doses is poor across all specialties, and there is a significant inverse relationship between experience and awareness of CT dose and risk. Despite having a poor understanding of these concepts, most doctors claim to consider them prior to requesting scans and when discussing potential risks with patients. © 2012 The Authors. Journal of Medical Imaging and Radiation Oncology © 2012 The Royal Australian and New Zealand College of Radiologists.

Sensitivity of APSIM/ORYZA model due to estimation errors in solar radiation

OpenAIRE

Alexandre Bryan Heinemann; Pepijn A.J. van Oort; Diogo Simões Fernandes; Aline de Holanda Nunes Maia

2012-01-01

Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs) data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, ...

Medical effects and risks of exposure to ionising radiation

International Nuclear Information System (INIS)

Mettler, Fred A

2012-01-01

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. (note)

Review of problems and methods for radiation risk assessment in the environment of a nuclear power plant

International Nuclear Information System (INIS)

Grgic, M.

1966-01-01

Radiation impact on the nuclear power plant environment is a very important problem which has to be solved during design and construction. Damage that could be caused by release of radioactive material into the environment should be estimated and the magnitude of nuclear and radiation risk of the power plant should be evaluated. In general the accuracy of estimation is rather poor due to statistical fluctuations of the conditions which influence radioactivity expansion in the environment, especially in the air. Different uncertainties and unresolved problems influence the inaccuracy. Since any real risk should be extremely small compared to potential risk i.e. risk induced by nuclear power plant without any safety measures, even inaccurate estimations are very useful. Method for environmental radiation risk assessment is based on relatively simple models of radiation expansion in the environment and in the air. These models are theoretically solved but they are based on relatively limited number of experimental data. Assessment of the radiation effects on the population health and mortality is an important problem [sl

Risk estimates for bone

International Nuclear Information System (INIS)

Schlenker, R.A.

1982-01-01

Bone sarcoma data for 226 228 Ra and 224 Ra are analyzed within the dosage ranges where the observed risk is zero. The uncertainty in the risk may be effectively illustrated by using pairs of functions based on a statistically-based measure of confidence. For radiation protection, the appropriate measure of risk is cumulative incidence in the presence of competing risks, as this takes into account the reduction of radiation effects brought about by natural mortality

Estimating risks of radiotherapy complications as part of informed consent: the high degree of variability between radiation oncologists may be related to experience

International Nuclear Information System (INIS)

Shakespeare, Thomas Philip; Dwyer, Mary; Mukherjee, Rahul; Yeghiaian-Alvandi, Roland; Gebski, Val

2002-01-01

Purpose: Estimating the risks of radiotherapy (RT) toxicity is important for informed consent; however, the consistency in estimates has not been studied. This study aimed to explore the variability and factors affecting risk estimates (REs). Methods and Materials: A survey was mailed to Australian radiation oncologists, who were asked to estimate risks of RT complications given 49 clinical scenarios. The REs were assessed for association with oncologist experience, subspecialization, and private practice. Results: The REs were extremely variable, with a 50-fold median variability. The least variability (sevenfold) was for estimates of late, small intestinal perforation/obstruction after a one-third volume received 50 Gy with concurrent 5-fluorouracil (RE range 5-35%). The variation between the smallest and largest REs in 17 scenarios was ≥100-fold. The years of experience was significantly associated with REs of soft/connective-tissue toxicity (p=0.01) but inversely associated with estimates of neurologic/central nervous system toxicity (p=0.08). Ninety-six percent of respondents believed REs were important to RT practice; only 24% rated evidence to support their estimates as good. Sixty-seven percent believed national/international groups should pursue the issue further. Conclusion: Enormous variability exists in REs for normal tissue complications due to RT that is influenced by the years of experience. Risk estimation is perceived as an important issue without a good evidence base. Additional studies are strongly recommended

Real and perceived risks of medical radiation exposure

International Nuclear Information System (INIS)

Hendee, W.R.

1983-01-01

After considering all the evidence related to the health effects of exposure to low levels of radiation, it is apparent that the risk is immeasurably small to any single person in a population exposed to small amounts of radiation. However, multiplying this immeasurably small estimate of risk by very large populations yields numbers that seem to imply that significant health effects (cancer, malformations, genetic effects) occur following exposure to small quantities of radiation. Although many advisory groups have cautioned against this procedure and conclusion, both continue to be used by some scientists and political action groups. In a public opinion poll conducted by Decision Research, Inc. of Eugene, Oregon, three groups were asked to rank the relative risks of various societal activities. Two of the three groups ranked nuclear power as the most hazardous of all societal activities, with a risk factor greater than that for smoking, automobiles, handguns and alcohol. Actually, nuclear power is the least hazardous of all 30 of the activities included in the poll. It is a conservative posture and probably a wise course of action to assume that exposure to any amount of radiation carries with it some element of risk. For example, requests for x-ray studies and nuclear medicine procedures should always be accompanied by an appreciation of the possibility of risk to the patient and to radiological personnel. At the same time, this element of risk should be placed in a realistic perspective by comparing it with other risks we assume every day

Children's exposure to diagnostic medical radiation and cancer risk: epidemiologic and dosimetric considerations

International Nuclear Information System (INIS)

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

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, CT, and fluoroscopically guided procedures. (orig.)

Dose-stochastic radiobiological effect relationship in model of two reactions and estimation of radiation risk

International Nuclear Information System (INIS)

Komochkov, M.M.

1997-01-01

The model of dose-stochastic effect relationship for biological systems capable of self-defence under danger factor effect is developed. A defence system is realized in two forms of organism reaction, which determine innate μ n and adaptive μ a radiosensitivities. The significances of μ n are determined by host (inner) factors; and the significances of μ a , by external factors. The possibilities of adaptive reaction are determined by the coefficient of capabilities of the defence system. The formulas of the dose-effect relationship are the solutions of differential equations of assumed process in the defence system of organism. The model and formulas have been checked both at cell and at human levels. Based on the model and personal monitoring data, the estimation of radiation risk at the Joint Institute for Nuclear Research is done

Perception of low dose radiation risks among radiation researchers in Korea

Science.gov (United States)

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 risk perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects risk perception of radiation exposure. PMID:28166286

Is energy imparted a good measure of the radiation risk associated with CT examinations

International Nuclear Information System (INIS)

Huda, W.

1984-01-01

The dose distribution in a Rando phantom has been measured for typical EMI 5005 CT scans of the head, chest, abdomen and pelvis. These dose distributions have been used to generate quantitative estimates of the somatic and genetic radiation risks associated with these CT examinations and also to measure the total energy imparted during each scan. A comparison has been made between the radiation risk estimates and the energy imparted measurements. The energy imparted measurements are not a good indicator of the somatic and/or genetic risks when one type of CT scan is compared with another. However, for a given type of scan, the energy imparted may be a reasonable indicator of the relative somatic risks associated with different CT examinations. Considerable care should be taken when interpreting and using any measured value of energy imparted in a radiological examination since published values of the risk per unit energy imparted can significantly underestimate the radiation risk. (author)

Radiobiology in clinical radiation therapy - Part IV: Long term risks - Carcinogenic, hereditary, and teratogenetic effects

International Nuclear Information System (INIS)

Brenner, David J.

1996-01-01

The long-term risks induced by radiation are of much concern to patients and clinicians alike. As an example, perceived radiation risks are frequently cited in a woman's decision to choose a radical mastectomy over lumpectomy + radiation. In consequence, the actual radiation risks are often considerably overstated, or unreasonably downplayed. In this lecture we will discuss just what is known about the long term risks following radiotherapy, both from the human experience and from the laboratory. We will discuss risks both to the patient and to radiotherapy personnel. A good deal is known about the carcinogenic effects of high and low doses of radiation, in large part thanks to the careful study of the survivors of the atomic bombing in Japan, as well as studies of individuals exposed to medical x rays. It is possible to make an estimate, which is probably good to within a factor of, perhaps, three to five, of the cancer risks faced by a patient of a particular age and sex who is going to undergo a particular radiotherapeutic regimen. It is also possible to make an estimate of the risks faced by radiotherapy and nursing staff exposed to low doses. Brachytherapy related risk estimates are likely to be somewhat more uncertain, due to the poorly known sparing effects of the low dose rates used; for the radiotherapy personnel in brachytherapy, because of the doses which can be received, the risks can be quite significant. A recent complication in external-beam radiotherapy is the advent of high-energy linacs, which can produce a significant fast neutron dose which, dose for dose, may be ten to fifty times more carcinogenic than gamma rays. Data relating to the risks of hereditary effects of radiation come almost entirely from laboratory experiments in animals. Studies involving several million mice form the basis of most of our current understanding of hereditary effects. The results of these studies indicate that radiation is a relatively inefficient mutagen. The

Lifetime attributable risk for cancer from occupational radiation exposure among radiologic technologists

Energy Technology Data Exchange (ETDEWEB)

Moon, Eun Kyeong; Lee, Won Jin [Dept. of Preventive Medicine, Korea University College of Medicine, Seoul (Korea, Republic of)

2016-12-15

Medical radiation workers were among the earliest occupational groups exposed to external ionizing radiation due to their administration of a range of medical diagnostic procedures. Ionizing radiation is a confirmed human carcinogen for most organ sites. This study, therefore, was aimed to estimate lifetime cancer risk from occupational exposure among radiologic technologists that has been recruited in 2012-2013. Our findings showed a small increased cancer risk in radiologic technologists from their occupational radiation exposure in Korea. However, continuous dose monitoring and strict regulation on occupational safety at the government level should be emphasized to prevent any additional health hazards from occupational radiation exposure. Our findings showed a small increased cancer risk in radiologic technologists from their occupational radiation exposure in Korea. However, continuous dose monitoring and strict regulation on occupational safety at the government level should be emphasized to prevent any additional health hazards from occupational radiation exposure.

Lifetime attributable risk for cancer from occupational radiation exposure among radiologic technologists

International Nuclear Information System (INIS)

Moon, Eun Kyeong; Lee, Won Jin

2016-01-01

Medical radiation workers were among the earliest occupational groups exposed to external ionizing radiation due to their administration of a range of medical diagnostic procedures. Ionizing radiation is a confirmed human carcinogen for most organ sites. This study, therefore, was aimed to estimate lifetime cancer risk from occupational exposure among radiologic technologists that has been recruited in 2012-2013. Our findings showed a small increased cancer risk in radiologic technologists from their occupational radiation exposure in Korea. However, continuous dose monitoring and strict regulation on occupational safety at the government level should be emphasized to prevent any additional health hazards from occupational radiation exposure. Our findings showed a small increased cancer risk in radiologic technologists from their occupational radiation exposure in Korea. However, continuous dose monitoring and strict regulation on occupational safety at the government level should be emphasized to prevent any additional health hazards from occupational radiation exposure.

Cancer risk estimation from the A-bomb survivors

International Nuclear Information System (INIS)

Pierce, D.A.; Vaeth, M.

1989-10-01

Generalizations regarding radiogenic cancer risks from the A-bomb survivor data of the Radiation Effects Research Foundation involve a large number of well-identified uncertainties and approximations. These include extrapolation to low doses and dose rates, projections in time, sampling variation, the quality of the data, extrapolation to other populations, and the use of simplifying conventions. This paper discusses some of these issues, with emphasis on the first three. Results are given regarding the maximum 'linear-quadratic' curvature consistent with these data, taking into account uncertainties in individual exposure estimates. Discussion is given regarding use of relative risk models and projection of lifetime risks, emphasizing results for those who were old enough at exposure to have been followed up for a major part of their lives by now, and stressing the speculative aspects of conclusions about those exposed as children. Combining these results, and brief discussion of other uncertainties itemized above, comment is made on the evolution of risk estimates over the past 15 years. (author)

Estimated population exposure from nuclear power production and other radiation sources

International Nuclear Information System (INIS)

Pochin, E.E.

1976-01-01

Estimates are given of the total radiation dose from all forms of ionizing radiation resulting from nuclear power reduction. A power consumption of 1kW per head of population, derived entirely from nuclear energy, would increase the average radiation exposure of the whole population from 100mrem per year from natural sources (plus about 40mrem per year from medical procedures and other artificial causes) by about 6mrem per year. The genetically signifificant component of this increase would be about 4mrem per year. Available estimates of harm from radiation would indicate that this would give a risk per year per million of population of about 1 fatal induced malignancy, about the same number of malignancies fully treatable by operation, and, after many generations, about the same number of inherited defects, of greater or less severity, per year. Accidental injuries, particularly in constructional and mining work, would cause an estimated 1 fatality and 50 other accidents annually. Indications are given of the number of fatalities and accidents involved in equal power production by alternative methods, and of the value and limitations of such numerical comparisons in reaching decisions on the development of future power programmes

Radiation, cancer risk, and the new dosimetry

International Nuclear Information System (INIS)

Mole, R.H.

1987-01-01

This letter discusses revision of risk estimates in the light of the new dosimetry (DS86) and concludes that direct observation is more to be relied on than the extrapolation from A-bomb survivors' experience. X-ray treatment for ankylosing spondylitis, cervical cancer data, and figures observed from 50,000 workers occupationally exposed to radiation are used as examples. (U.K.)

From 'Image Gently' to image intelligently: a personalized perspective on diagnostic radiation risk

Energy Technology Data Exchange (ETDEWEB)

Guillerman, R.P. [Department of Pediatric Radiology, Texas Children' s Hospital, Baylor College of Medicine, Houston, TX (United States)

2014-10-15

The risk of ionizing radiation from diagnostic imaging has been a popular topic in the radiology literature and lay press. Communicating the magnitude of risk to patients and caregivers is problematic because of the uncertainty in estimates derived principally from epidemiological studies of large populations, and alternative approaches are needed to provide a scientific basis for personalized risk estimates. The underlying patient disease and life expectancy greatly influence risk projections. Research into the biological mechanisms of radiation-induced DNA damage and repair challenges the linear no-threshold dose-response assumption and reveals that individuals vary in sensitivity to radiation. Studies of decision-making psychology show that individuals are highly susceptible to irrational biases when judging risks. Truly informed medical decision-making that respects patient autonomy requires appropriate framing of radiation risks in perspective with other risks and with the benefits of imaging. To follow the principles of personalized medicine and treat patients according to their specific phenotypic and personality profiles, diagnostic imaging should optimally be tailored not only to patient size, body region and clinical indication, but also to underlying disease conditions, radio-sensitivity and risk perception and preferences that vary among individuals. (orig.)

How health risk from radiation is assessed

International Nuclear Information System (INIS)

Rahm-Crites, L.

1994-07-01

The likelihood that a dose of radiation will result in death from cancer at some future time can be estimated by multiplying the dose equivalent by a risk factor, or dose-to-risk conversion factor. Conversion factors, which are based on studies of atomic bomb survivors and others, provide approximate predictions of the health effects to be expected from a given radiological exposure. Following recommendations of the Nuclear Regulatory Commission, the Department of Energy currently uses risk conversion factors of 4 x 10 -4 (0.0004 LCFs) per person-rem for workers and 5 x 10 -4 (0.0005 LCFs) per person-rem for the general public (NRC 1991; DOE 1993). The conversion factor for general public is slightly higher than that for workers because the general public includes infants and children, who are more susceptible to cancer. The current overall death rate from cancer in the United States is between 20 and 25 percent, in other words, cancer accounts for one out of nearly every four deaths. An action affecting a population of 20,000 people, with the estimated potential to induce one latent cancer fatality, should therefore be understood as adding one death from cancer to a normally expected total of 4500. Studies dedicated to improving their ability to predict radiation health effects are constantly in progress, nationally and internationally, and risk conversion factors are periodically revised to incorporate new experimental and epidemiological information

The risks of leukaemia and other cancers in Seascale from radiation exposure

International Nuclear Information System (INIS)

Stather, J.W.; Dionian, J.; Brown, J.; Fell, T.P.; Muirhead, C.R.

1986-04-01

Including new data in the radiation dose calculations for the Seascale study population of 1225 children and young persons, followed to 20 years of age or 1980, has, with modifications to dosimetric models, increased the predicted number of radiation-induced leukaemia resulting from Sallafield discharges from 0.01 to 0.016. Risk to the average child in the study, from the discharges, is now calculated as about 1 in 75,000 with a maximum risk of about 1 in 30,000 for children born in the mid-1950s. For the four fatal leukemias to be attributed to the Sellafield operations, the calculated average risk for all the children would have to be increased about 250 times. Estimate of the overall risk of radiation-induced leukaemia in the study population, from combined sources, has increased by less than 10% of the previous estimate and the total number of cases is still rounded to 0.1, as in R171. Risk to the average child is now calculated as about 1 in 12,250, about two thirds from natural background, 16% from Sellafield discharges, and 9% each from weapons fallout and medical exposure. (U.K.)

New radiobiological, radiation risk and radiation protection paradigms

International Nuclear Information System (INIS)

Goodhead, Dudley T.

2010-01-01

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.

Assessment of radiation risk as a part of ecological risk in the Republic of Belarus after the Chernobyl accident

International Nuclear Information System (INIS)

Saltanova, Irina; Saltanov, Eugene

2008-01-01

Full text: The purpose of the work: foundation for principles of planning protection measures, that provide safety for population activity on the territories, contaminated with radio-nuclides, by analysing radio-chemical situation, using risk assessment methods. Problems set in the work: -) Analyses of radiation risk in the structure of ecological risk in the territory of the Republic of Belarus after the Chernobyl accident; -) Investigation of chemical risk level, connected with air pollution from stationary objects exhausts, for the territories, contaminated with Chernobyl radio-nuclides; -) Modelling of the combined impact of ionising radiation and chemical carcinogen for the possible ecological risk assessment; -) Involving modern geo informational systems in the radio-ecological risk assessment process; -) Foundation for the assessment methodology of the complex influence of negative factors in the territories, contaminated with Chernobyl radio-nuclides. The problems are solved by carrying out specific experiments and by analysing published and own data on radioactive and chemical contamination of some regions of Belarus. Major findings: Radiation input to the really registered carcinogens is estimated to app. 10 %. In case of multiple factors influence of different contaminators of industrial and natural origin (i.e. radiation is not the only negative factor), ignorance of non-radiation origin factors may seriously distort estimation of radiation risk, when it is related to the registered effects. Radiation should be in no way treated as the major factor of real ecological risk in Belarus. Method for comparative analysis of territories' ecological risk level is developed and implemented. A GIS segment, that includes subsystem of the real and forecasted radio-ecological mapping, is created. The authors grounded the experimental model for study the complex influence of radioactive and non-radioactive (chemical carcinogen) factors. Revealed dependencies 'dose

Radiation exposure and radiation risk of the population

International Nuclear Information System (INIS)

Jacobi, W.; Paretzke, H.G.; Ehling, U.H.

1981-02-01

The major scientifically founded results concerning the assessment of the radiation exposure and the analysis and evaluation of the radiationhazards for the population, particularly in the range of low doses, are presented. As to the risk analysis special attention is paid to the rays with low ionization density (X-, γ-, β- and electronrays). Contents: 1) Detailed survey of the results and conclusions; 2) Data on the radiation load of the population; 3) Results to epidemiological questioning on the risk of cancer; 4) Genetical radiation hazards of the population. For quantification purposes of the risk of cancer by γ-radiation the observations with the a-bomb survivors in Japan are taken as a basis, as the available dosimetrical data have to be revised. Appendices: 1) German translation of the UNSCEAR-Report (1977); 2) BEIR-Report (1980); 3) Comments from the SSK on the comparability of the risks of natural-artificial radiation exposure; 4) Comments from the SSK on the importance of synergistical influences for the radiation protection (23.9.1977). (HP) [de

Air travel and radiation risks - review of current knowledge

International Nuclear Information System (INIS)

Zeeb, H.; Blettner, M.

2004-01-01

Aircrew and passengers are exposed to cosmic radiation, in particular when travelling routes close to the poles and in high altitudes. The paper reviews current radiation measurement and estimation approaches as well as the actual level of cosmic radiation that personnel and travellers receive and summarizes the available epidemiological evidence on health effects of cosmic radiation. On average, German aircrew is exposed to les than 5 mSv per annum, and even frequent travellers only rarely reach values above 1 mSv/year. Cohort studies among aircrew have found very little evidence for an increased incidence or mortality of radiation-associated cancers. Only malignant melanoma rates have consistently found to be increased among male aircrew. Socioeconomic and reproductive aspects are likely to contribute to the slightly elevated breast cancer risk of female aircrew. Cytogenetic studies have not yielded consistent results. Based on these data overall risk increases for cancer among occupationally exposed aircrew appear unlikely. This also applies to air travellers who are usually exposed to much lower radiation levels. Occasional air travel during pregnancy does not pose a significant radiation risk, but further considerations apply in this situation. The currently available studies are limited with regard to methodological issues and case numbers so that a continuation of cohort studies in several European countries is being planned. (orig.) [de

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

Science.gov (United States)

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

2014-06-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Yoon, Myonggeun; Lee, Hyunho; Sung, Jiwon [Korea University, Seoul (Korea, Republic of); Shin, Dongoh [Kyung Hee University Medical Center, Seoul (Korea, Republic of); Park, Sungho [Ulsan University Hospital, Ulsan (Korea, Republic of); Chung, Weonkuu; Jahng, Geonho; Kim, Dongwook [Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of)

2014-06-15

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

Limitations and problems in deriving risk estimates for low-level radiation exposure

International Nuclear Information System (INIS)

Cohen, B.L.

1981-01-01

Some of the problems in determining the cancer risk of low-level radiation from studies of exposed groups are reviewed and applied to the study of Hanford workers by Mancuso, Stewart, and Kneale. Problems considered are statistical limitations, variation of cancer rates with geography and race, the ''healthy worker effect,'' calendar year and age variation of cancer mortality, choosing from long lists, use of proportional mortality rates, cigarette smoking-cancer correlations, use of averages to represent data distributions, ignoring other data, and correlations between radiation exposure and other factors that may cause cancer. The current status of studies of the Hanford workers is reviewed

Ionizing radiation: benefits vs. risks

International Nuclear Information System (INIS)

Wagner, H.N. Jr.

1986-01-01

No one has been identifiably injured by radiation within the levels set by the NCRP and ICRP in 1934. This fact and the level of natural radiation (average dose 102 millirems/year) help provide standards against which the authors can view the relative increases in exposure from manmade sources of radiation. Because one person in five in the US will die of cancer from all causes, it is impossible to detect small increases in some types of cancer from radiation. A valid assumption is that any exposure to radiation carries some possibility of harm and should be kept below the level of the expected benefits. More is known about radiation toxicity than about any other potentially toxic substances. An obstacle to progress in the use of radioactive materials in biology and medicine is an exaggerated impression by the public of the risk of radiation. Several studies indicate that the public perceives the risk of radiation to be the greatest of all societal risks and at times does not distinguish peaceful from military uses of radiation. It behooves scientists and physicians to inform the public about the benefits as well as the risks of procedures involving radiation

Radiation effects, nuclear energy and comparative risks

International Nuclear Information System (INIS)

Gopinath, D.V.

2007-01-01

Nuclear energy had a promising start as an unlimited, inexpensive and environmentally benign source of energy for electricity generation. However, over the decades its growth was severely retarded due to concerns about its possible detrimental effects on the well-being of mankind and the environment. Since such concerns are essentially due to the gigantic magnitude of radioactivity and ionizing radiations associated with nuclear energy, this article starts with a comprehensive account of effects of the ionizing radiation on living systems. Quantitative description of types of radiation exposure and their varied effects is given. The origin, type and magnitude of mutagenic effects of radiation are described. The concept of radiation risk factors, basis for their evaluation and their currently accepted values are presented. With this background, origin and magnitude of radioactivity and associated ionizing radiations in nuclear reactors are presented and the elaborate measures to contain them are described. It is recognized that notwithstanding all the measures taken in the nuclear industry, certain amount of radiation exposure, however small, is inevitable and the values, based on the experience world over, are presented. Estimated health risk due to such exposures is evaluated. For a comparative analysis, risks in other options of electricity generation such as hydel and fossil-fuelled plants are described. It is seen that on an overall basis, the nuclear option is no more risky than the other commonly employed options, and is in fact, significantly less. Lastly, since every option of electricity generation entails some risk, the case of 'no addition of electricity, and its impact on the society are considered. Based on the analysis of extensive data provided by UNDP on the human development parameters for different countries in the world, it is shown that at least for developing countries, any option of addition of electricity would be far more desirable than the

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

Science.gov (United States)

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 perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects perception of radiation exposure.

Reduction of the estimated radiation dose and associated patient risk with prospective ECG-gated 256-slice CT coronary angiography

International Nuclear Information System (INIS)

Efstathopoulos, E P; Kelekis, N L; Pantos, I; Brountzos, E; Argentos, S; Grebac, J; Ziaka, D; Seimenis, I; Katritsis, D G

2009-01-01

Computed tomography (CT) coronary angiography has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but high radiation doses have been reported. Prospective ECG-gating using a 'step-and-shoot' axial scanning protocol has been shown to reduce radiation exposure effectively while maintaining diagnostic accuracy. 256-slice scanners with 80 mm detector coverage have been currently introduced into practice, but their impact on radiation exposure has not been adequately studied. The aim of this study was to assess radiation doses associated with CT coronary angiography using a 256-slice CT scanner. Radiation doses were estimated for 25 patients scanned with either prospective or retrospective ECG-gating. Image quality was assessed objectively in terms of mean CT attenuation at selected regions of interest on axial coronary images and subjectively by coronary segment quality scoring. It was found that radiation doses associated with prospective ECG-gating were significantly lower than retrospective ECG-gating (3.2 ± 0.6 mSv versus 13.4 ± 2.7 mSv). Consequently, the radiogenic fatal cancer risk for the patient is much lower with prospective gating (0.0176% versus 0.0737%). No statistically significant differences in image quality were observed between the two scanning protocols for both objective and subjective quality assessments. Therefore, prospective ECG-gating using a 'step-and-shoot' protocol that covers the cardiac anatomy in two axial acquisitions effectively reduces radiation doses in 256-slice CT coronary angiography without compromising image quality.

Management of radiation risk

International Nuclear Information System (INIS)

Hubert, P.

1996-01-01

The need to control the risk from ionizing radiation can be tracked back to the eve of the twentieth century. However, as knowledge improved and practices expanded, the approaches to this control have evolved. No longer is the mere respect of some forms of exposure limits or safety related standards sufficient. Rather, it is widely admitted that there is a need for managing radiation risk, both by balancing the advantages and disadvantages of enhancing protection and by setting up a proper organization that allows handling of the risk. This paper describes the multiple aspects of radiation risk management and points out the main related issues. It critically analyzes ALARA and ICRP recommendations. 74 refs, 8 figs, 5 tabs

Radiation risk assessment for the transport of radioisotopes using KRI-BGM B(U) type container

International Nuclear Information System (INIS)

Cho, Woon-Kap

2008-01-01

The radiation risks were estimated for the transportation of radioisotopes using KRI-BGM transport container. KRI-BGM container was specially designed for transportation of large amount of radioisotopes for industrial or medical applications. The container can carry maximum 370 TBq of solid Ir-192, 29.6 TBq of liquid Mo-99 and 37 TBq of liquid I-131 respectively. For the radiation risk assessment, it was assumed that maximum design activity of those radioisotopes was transported. Transportation route is from Daejeon where radioisotopes are produced to Seoul where radioisotopes are consumed. Transport distance is 200 km including highway and downtown area from Daejeon to Seoul. As the transportation conveyance, an ordinary cargo truck is used exclusively. Radiation risks were estimated for incident free and accident condition of transportation and RADTRAN 5.6 was used as the risk assessment tool. For the risk assessment of radioisotopes transportation, various parameters such as population density around transport route, weather condition, probability of specific accidents such as impact, fire, etc. were considered. From the results of this study, the exclusive transportation of radioisotopes using KRI-BGM transport container by truck showed low radiological risks with manageable safety and health consequences. This paper discusses the methods and results of the radiation risks assessment for the radioisotopes transportation by an ordinary truck and presents the expected radiation risks in person-Sv and latent cancer fatalities. (author)

Fundamental matters on radiation risk communication

International Nuclear Information System (INIS)

Shinohara, Kunihiko; Nagai, Hiroyuki; Yonezawa, Rika; Ohuchi, Hiroko; Chikamoto, Kazuhiko; Taniguchi, Kazufumi; Morimoto, Eriko

2009-01-01

In the field of atomic energy and radiation utilization, radiation risk is considered as one of the social uneasy factors. About the perception of risks, there is a gap between experts and general public (non-experts). It is said that the general public tends to be going to judge risk from intuitive fear and a visible concrete instance whereas the experts judge it scientifically. A company, an administration or experts should disclose relating information about the risks and communicate interactively with the stakeholders to find the way to solve the problem with thinking together. This process is called 'risk communication'. The role of the expert is important on enforcement of risk communication. They should be required to explain the information on the risks with plain words to help stakeholders understand the risks properly. The Japan Health Physics Society (JHPS) is the largest academic society for radiation protection professionals in Japan, and one of its missions is supposed to convey accurate and trustworthy information about the radiation risk to the general public. The expert group on risk communication of ionizing radiation of the JHPS has worked for the purpose of summarizing the fundamental matters on radiation risk communication. 'Lecture on risk communication for the members of the JHPS.' which has been up on the JHPS web-site, and the symposium of 'For better understanding of radiation risk.' are a part of the activities. The expert group proposes that the JHPS should enlighten the members continuously for being interested in and practicing risk communication of radiation. (author)

Solid cancer risks from radiation exposure for the Australian population

International Nuclear Information System (INIS)

Wise, K.N.

2003-01-01

Estimates are made of the risks to the Australian population as a function of age and gender for mortality or morbidity for all solid cancers after exposure to radiation. Excess relative risk (ERR) and excess absolute risk (EAR) models are used. The model coefficients are re-evaluated for radiation doses expressed as effective dose using data from the Japanese Life Span Study. Life-table methods are used throughout and the risk measures studied are: the risk of exposure related death, RERD and the risk of exposure related cancer, RERC. Australian life-table data and the age-specific cancer incidence and mortality rates of Australian males and females are taken from recent published tables. No dose and dose-rate effectiveness factor is applied. Sources of uncertainty used to calculate the confidence regions for the estimated risks include the statistical uncertainties of the model parameters and of the extrapolation of the risks beyond the period supported by the epidemiological data. Summary values of the risks are reported as averages of those calculated from the ERR and the EAR models. For males, the mortality risks per sievert range from 14% for 0-9 year age group, 7% at 30-39 years and 4% at 50-59 years. Corresponding values for females are 20%, 10% and 6%. Incidence risks are higher: for males the estimates are 32% for the 0-9 year group, 12% at 30-39 and 5% at 50-59. Corresponding values for females are 56%, 20% and 8%. The 90% confidence regions are about ± 50% of these values. Estimates are given for the risks from CT whole-body scanning or virtual colonoscopy which could be used for cancer screening. If used at 3 year intervals and the effective dose per procedure is 10 mSv, then the RERD for males beginning screening at 40, 50 and 60 years is 0.4%, 0.3% and 0.1%, respectively and for females, 0.6%, 0.4% and 0.2%, respectively. RERD estimates for a 5 year interval between screens are about one-third smaller. Copyright (2003) Australasian College of

Report on some methods of determining the state of convergence of Monte Carlo risk estimates

International Nuclear Information System (INIS)

Orford, J.L.; Hufton, D.; Johnson, K.

1991-05-01

The Department of the Environment is developing a methodology for assessing potential sites for the disposal of low and intermediate level radioactive wastes. Computer models are used to simulate the groundwater transport of radioactive materials from a disposal facility back to man. Monte Carlo methods are being employed to conduct a probabilistic risk assessment (pra) of potential sites. The models calculate time histories of annual radiation dose to the critical group population. The annual radiation dose to the critical group in turn specifies the annual individual risk. The distribution of dose is generally highly skewed and many simulation runs are required to predict the level of confidence in the risk estimate i.e. to determine whether the risk estimate is converged. This report describes some statistical methods for determining the state of convergence of the risk estimate. The methods described include the Shapiro-Wilk test, calculation of skewness and kurtosis and normal probability plots. A method for forecasting the number of samples needed before the risk estimate is converged is presented. Three case studies were conducted to examine the performance of some of these techniques. (author)

Formation of potential radiation risk groups to render timely targeted medical care: Lessons of Chernobyl

International Nuclear Information System (INIS)

Ivanov, V. K.; Kashcheev, V. V.; Zamulaeva, I. A.; Saenko, A. S.; Orlova, N. V.; Smirnova, S. G.; Korelo, A. M.; Gorsky, A. I.; Maksioutov, M. A.

2012-01-01

The paper discusses technology for establishing potential cancer risk groups, based on methods of molecular and radiation epidemiology. Assay of gene mutations at the T-cell receptor (TCR) locus as the method of molecular epidemiology was used for measuring the frequency of TCR-mutations in 320 nuclear workers of the Inst. of Physics and Power Engineering (IPPE). The method of radiation epidemiology was applied to the estimation of attributable risk fraction (ARF) for solid cancers in these groups. The main estimates of radiation risk after the Chernobyl accident are in close agreement with the International Commission on Radiological Protection (ICRP) Publication, 103 models published in 2007. In nuclear workers of the IPPE with ARF ≥ 10%, the increased level of TCR-mutations occurs more often (risk ratio=9.7; 95% CI: 2.9; 32.1). (authors)

Dose dependence on stochastic radiobiological effect in radiation risk estimation

International Nuclear Information System (INIS)

Komochkov, M.M.

1999-01-01

The analysis of the results in dose -- effect relationship observation has been carried out on the cell and organism levels, with the aim to obtain more precise data on the risk coefficients at low doses. The results are represented by two contrasting groups of dose dependence on effect: a downwards concave and a J-shaped curve. Both types of dependence are described by the equation solutions of an assumed unified protective mechanism, which comprises two components: constitutive and adaptive or inducible ones. The latest data analysis of the downwards concave dependence curves shows a considerable underestimation of radiation risk in all types of cancer, except leukemia, for a number of critical groups in a population, at low doses comparing to the ICRP recommendations. With the dose increase, the decrease of the effect value per dose unit is observed. It may be possibly related to the switching of the activity of the adaptive protective mechanism, with some threshold dose values being exceeded

Risks associated with utilization of radiation

International Nuclear Information System (INIS)

Matsuoka, Satoshi; Kumazawa, Shigeru; Aoki, Yoshiro; Nakamura, Yuji; Takeda, Atsuhiko; Kusama, Tomoko; Inaba, Jiro; Tanaka, Yasumasa.

1993-01-01

When mankind decides action, the conveniences and the risks obtained by the action are weighed up. When socially important judgement is done, the logical discussion based on objective data is indispensable. The utilization of radiation spread from industrial circles to general public, accordingly the circumstances changed from the recognition of its risks by professionals to that by general public. The radiation exposure dose of public has increased rapidly by medical treatment. The global radioactivity contamination accompanying nuclear explosion experiment and the Chernobyl accident raised the psychological risk recognition of public. Now, the fear of the potential radioactivity which may be released from nuclear power plants and nuclear fuel cycle facilities expanded. The radiation exposure due to its utilization in recent years is mostly at the level below natural radiation. The acute radiation syndrome by whole body exposure is shown, and the effect is probabilistic. The evaluation of the risks due to radiation in the early effect, the hereditary effect and the delayed effect including canceration is explained. The risks in general human activities, the concept of risks in radiation protection, the effect of Chernobyl accident and the perception of general public on radiation risks are reported. (K.I.)

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

Energy Technology Data Exchange (ETDEWEB)

Kim, D [Kyung Hee University International Med. Serv., Seoul (Korea, Republic of); Chung, W [Kyung Hee University Hospital at Gangdong, Seoul, Seoul (Korea, Republic of); Shin, D [Kyung Hee University Hospital, Seoul, Seoul (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of)

2014-06-01

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

Relations between radiation risks and radiation protection measuring techniques

International Nuclear Information System (INIS)

Herrmann, K.; Kraus, W.

Relations between radiation risks and radiation protection measuring techniques are considered as components of the radiation risk. The influence of the exposure risk on type and extent of radiation protection measurements is discussed with regard to different measuring tasks. Based upon measuring results concerning the frequency of certain external and internal occupational exposures in the GDR, it has been shown that only a small fraction of the monitored persons are subjected to a high exposure risk. As a consequence the following recommendations are presented: occupationally exposed persons with small exposure risk should be monitored using only a long-term desimeter (for instance a thermoluminescence desimeter). In the case of internal exposure, the surface and air contamination levels should be controlled so strictly that routine measurements of internal contamination need not be performed

Aspects of risk analysis application to estimation of nuclear accidents and tests consequences and intervention management

International Nuclear Information System (INIS)

Demin, V.F.; Hedemann-Jensen, P.; Rolevich, I.V.; Schneider, T.S.; Sobolev, B.G.

1996-01-01

For assessment of accident consequences and a post-accident management a risk analysis methodology and data bank (BARD) with allowance for radiation and non-radiation risk causes should be developed and used. Aspects of these needs and developments are considered. Some illustrative results of health risk estimation made with BARD for the Bryansk region territory with relatively high radioactive contamination from the Chernobyl accident are presented

Effective doses and standardised risk factors from paediatric diagnostic medical radiation exposures: Information for radiation risk communication

International Nuclear Information System (INIS)

Bibbo, Giovanni

2018-01-01

In the paediatric medical radiation setting, there is no consistency on the radiation risk information conveyed to the consumer (patient/carer). Each communicator may convey different information about the level of risk for the same radiation procedure, leaving the consumer confused and frustrated. There is a need to standardise risks resulting from medical radiation exposures. In this study, paediatric radiographic, fluoroscopic, CT and nuclear medicine examination data have been analysed to provide (i) effective doses and radiation induced cancer risk factors from common radiological and nuclear medicine diagnostic procedures in standardised formats, (II) awareness of the difficulties that may be encountered in communicating risks to the layperson, and (iii) an overview of the deleterious effects of ionising radiation so that the risk communicator can convey with confidence the risks resulting from medical radiation exposures. Paediatric patient dose data from general radiographic, computed tomography, fluoroscopic and nuclear medicine databases have been analysed in age groups 0 to <5 years, 5 to <10 years, 10 to <15 years and 15 to <18 years to determine standardised risk factors. Mean, minimum and maximum effective doses and the corresponding mean lifetime risks for general radiographic, fluoroscopic, CT and nuclear medicine examinations for different age groups have been calculated. For all examinations, the mean lifetime cancer induction risk is provided in three formats: statistical, fraction and category. Standardised risk factors for different radiological and nuclear medicine examinations and an overview of the deleterious effects of ionising radiation and the difficulties encountered in communicating the risks should facilitate risk communication to the patient/carer.

The effects and control of radiation

International Nuclear Information System (INIS)

Saunders, P.A.H.

1982-12-01

The subject is discussed under the headings: introduction; ionising radiation (alpha and beta particles, gamma- and X-radiation, neutrons, half-life, sources of radiation); biological effects; risk estimates (somatic) (early effects, delayed effects); risk estimates (hereditary); control of radiation; risk estimates (accidents). (U.K.)

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-06-01

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

Adjustment for smoking reduces radiation risk: fifth analysis of mortality of nuclear industry workers in Japan, 1999-2010

Energy Technology Data Exchange (ETDEWEB)

Kudo, S.; Ishida, J.; Yoshimoto, K.; Mizuno, S.; Ohshima, S.; Kasagi, F., E-mail: s_kudo@rea.or.jp [Instituto of Radiation Epidemiology, Radiation Effects Association, 1-9-16 Kajicho, Chiyoda-ku, 101-0044 Tokyo (Japan)

2015-10-15

Full text: Many cohort studies among nuclear industry workers have been carried out to determine the possible health effects of low-level radiation. In those studies, confounding factors, for example, age was adjusted to exclude the effect of difference of mortality by age to estimate radiation risk. But there are few studies adjusting for smoking that is known as a strong factor which affects mortality. Radiation Effects Association (Rea) initiated a cohort study of nuclear industry workers mortality in 1990. To examine non-radiation factors confounding on the mortality risk among the radiation workers, Rea have performed life-style questionnaire surveys among the part of workers at 1997 and 2003 and found the correlation between radiation dose and smoking rate. Mortality follow-up were made on 75,442 male respondents for an average of 8.3 years during the observation period 1999-2010. Estimates of Excess Relative Risk percent (Err %) per 10 mSv were obtained by using the Poisson regression. The Err for all causes was statistically significant (1.05 (90 % CI 0.31 : 1.80)), but no longer significant after adjusting for smoking (0.45 (-0.24 : 1.13)). The Err for all cancers excluding leukemia was not significant (0.92 (-0.30 : 2.16)), but after adjusting for smoking, it decreased (0.36 (-0.79 : 1.50)). Thus smoking has a large effect to obscure a radiation risk, so adjustment for smoking is important to estimate radiation risk. (Author)

Adjustment for smoking reduces radiation risk: fifth analysis of mortality of nuclear industry workers in Japan, 1999-2010

International Nuclear Information System (INIS)

Kudo, S.; Ishida, J.; Yoshimoto, K.; Mizuno, S.; Ohshima, S.; Kasagi, F.

2015-10-01

Full text: Many cohort studies among nuclear industry workers have been carried out to determine the possible health effects of low-level radiation. In those studies, confounding factors, for example, age was adjusted to exclude the effect of difference of mortality by age to estimate radiation risk. But there are few studies adjusting for smoking that is known as a strong factor which affects mortality. Radiation Effects Association (Rea) initiated a cohort study of nuclear industry workers mortality in 1990. To examine non-radiation factors confounding on the mortality risk among the radiation workers, Rea have performed life-style questionnaire surveys among the part of workers at 1997 and 2003 and found the correlation between radiation dose and smoking rate. Mortality follow-up were made on 75,442 male respondents for an average of 8.3 years during the observation period 1999-2010. Estimates of Excess Relative Risk percent (Err %) per 10 mSv were obtained by using the Poisson regression. The Err for all causes was statistically significant (1.05 (90 % CI 0.31 : 1.80)), but no longer significant after adjusting for smoking (0.45 (-0.24 : 1.13)). The Err for all cancers excluding leukemia was not significant (0.92 (-0.30 : 2.16)), but after adjusting for smoking, it decreased (0.36 (-0.79 : 1.50)). Thus smoking has a large effect to obscure a radiation risk, so adjustment for smoking is important to estimate radiation risk. (Author)

Magnitude estimate of occupational risks located in a radiative facility and its main health impacts

International Nuclear Information System (INIS)

Alves, Alice dos Santos; Gerulis, Eduardo; Carneiro, Janete C.G.G.

2014-01-01

The work routine of Radiopharmacy Center (CR) personnel of the Institute of Energy Research and Nuclear (IPEN / CNEN-SP) includes singularities not exist in other professions. Relevant examples to this study can be cited: exposure to physical, chemical, biological hazards, to accidents and ergonomic risks. The objective of this study is to conduct a quantitative and qualitative evaluation of occupational exposure existing in the workplace and its impact on the health of occupationally exposed individuals (IOE's). The proposed methodology was based on systematic observation and a questionnaire to the managers of each practice held at CR. The evaluation process involved three steps: a) characterization of exposure; b) identification of the main points of exposure and possible routes of exposure; c) quantifying of exposure. Seventeen occupational agents related to the tasks of different groups of IOE's were identified. Ionizing radiation (physical risk) and the situations that cause stress (ergonomic risk) had the highest frequencies. According to the applied methodology risks was considered mostly acceptable. Quantification of exposure was basically referring to physical risk agent (Ionizing radiation), because it is a radioactive installation. Based on the records analyzed, not was observed health risks to workers arising from the activities undertaken

Solar radiation estimation based on the insolation

International Nuclear Information System (INIS)

Assis, F.N. de; Steinmetz, S.; Martins, S.R.; Mendez, M.E.G.

1998-01-01

A series of daily global solar radiation data measured by an Eppley pyranometer was used to test PEREIRA and VILLA NOVA’s (1997) model to estimate the potential of radiation based on the instantaneous values measured at solar noon. The model also allows to estimate the parameters of PRESCOTT’s equation (1940) assuming a = 0,29 cosj. The results demonstrated the model’s validity for the studied conditions. Simultaneously, the hypothesis of generalizing the use of the radiation estimative formulas based on insolation, and using K = Ko (0,29 cosj + 0,50 n/N), was analysed and confirmed [pt

Children's exposure to diagnostic medical radiation and cancer risk: epidemiologic and dosimetric considerations

Energy Technology Data Exchange (ETDEWEB)

Linet, Martha S.; Rajaraman, Preetha [National Cancer Institute, Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, Bethesda, MD (United States); Kim, Kwang pyo [National Cancer Institute, Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, Bethesda, MD (United States); Kyung Hee University, Department of Nuclear Engineering, Yongin-si, Gyeonggi (Korea)

2009-02-15

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, CT, and fluoroscopically guided procedures. (orig.)

Estimating surface solar radiation from upper-air humidity

Energy Technology Data Exchange (ETDEWEB)

Kun Yang [Telecommunications Advancement Organization of Japan, Tokyo (Japan); Koike, Toshio [University of Tokyo (Japan). Dept. of Civil Engineering

2002-07-01

A numerical model is developed to estimate global solar irradiance from upper-air humidity. In this model, solar radiation under clear skies is calculated through a simple model with radiation-damping processes under consideration. A sky clearness indicator is parameterized from relative humidity profiles within three atmospheric sublayers, and the indicator is used to connect global solar radiation under clear skies and that under cloudy skies. Model inter-comparisons at 18 sites in Japan suggest (1) global solar radiation strongly depends on the sky clearness indicator, (2) the new model generally gives better estimation to hourly-mean solar irradiance than the other three methods used in numerical weather predictions, and (3) the new model may be applied to estimate long-term solar radiation. In addition, a study at one site in the Tibetan Plateau shows vigorous convective activities in the region may cause some uncertainties to radiation estimations due to the small-scale and short life of convective systems. (author)

Secondary Breast Cancer Risk by Radiation Volume in Women With Hodgkin Lymphoma

Energy Technology Data Exchange (ETDEWEB)

Conway, Jessica L. [Centre for Lymphoid Cancer, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Department of Surgery, University of British Columbia, Vancouver, British Columbia (Canada); Connors, Joseph M. [Centre for Lymphoid Cancer, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Tyldesley, Scott [Centre for Lymphoid Cancer, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Department of Surgery, University of British Columbia, Vancouver, British Columbia (Canada); Savage, Kerry J. [Centre for Lymphoid Cancer, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Campbell, Belinda A. [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Zheng, Yvonne Y.; Hamm, Jeremy [Department of Cancer Surveillance and Outcomes, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Pickles, Tom, E-mail: TPickles@bccancer.bc.ca [Centre for Lymphoid Cancer, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Department of Surgery, University of British Columbia, Vancouver, British Columbia (Canada)

2017-01-01

Purpose: To determine whether the risk of secondary breast cancer (SBC) is reduced in women with Hodgkin lymphoma (HL) treated with smaller field radiation therapy (SFRT) versus mantle field radiation therapy (MRT). Methods and Materials: We used the BC Cancer Agency (BCCA) Lymphoid Cancer Database to identify female patients treated for HL between January 1961 and December 2009. Radiation therapy volumes were categorized as MRT or SFRT, which included involved field, involved site, or involved nodal radiation therapy. SBC risk estimates were compared using competing risk analysis and Fine and Gray multivariable model: MRT ± chemotherapy, SFRT ± chemotherapy, or chemotherapy-only. Results: Of 734 eligible patients, 75% of the living patients have been followed up for more than 10 years, SBC has developed in 54, and 15 have died of breast cancer. The 20-year estimated risks (competing risk cumulative incidence) for SBC differed significantly: MRT 7.5% (95% confidence interval [CI] 4.4%-11.5%), SFRT 3.1% (95% CI 1.0%-7.7%), and chemotherapy-only 2.2% (95% CI 1.0%-4.8%) (P=.01). Using a Fine and Gray model to control for death and patients lost to follow-up, MRT was associated with a higher risk of SBC (hazard ratio [HR] = 2.9; 95% CI 1.4%-6.0%; P=.004) compared with chemotherapy-only and with SFRT (HR = 3.3; 95% CI 1.3%-8.4%; P=.01). SFRT was not associated with a greater risk of SBC compared with chemotherapy-only (HR = 0.87; 95% CI 0.28%-2.66%; P=.80). Conclusion: This study confirms that large-volume MRT is associated with a markedly increased risk of SBC; however, more modern small-volume RT is not associated with a greater risk of SBC than chemotherapy alone.

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

Energy Technology Data Exchange (ETDEWEB)

1980-12-01

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

Photometric estimation of defect size in radiation direction

International Nuclear Information System (INIS)

Zuev, V.M.

1993-01-01

Factors, affecting accuracy of photometric estimation of defect size in radiation transmission direction, are analyzed. Experimentally obtained dependences of contrast of defect image on its size in radiation transmission direction are presented. Practical recommendations on improving accuracy of photometric estimation of defect size in radiation transmission direction, are developed

Perception of risks from radiation by faculty and students of Nagasaki University

International Nuclear Information System (INIS)

Miura, Miwa; Yoshida, Masahiro; Takao, Hideaki; Matsuda, Naoki

2008-01-01

Although a variety of radiation-related education courses are provided in universities, information on faculty and student perceptions of radiation risk is limited. To obtain quantitative data on this issue, we conducted a written questionnaire survey at Nagasaki University on the perceived risks of 13 health hazards, of which six related to radiation exposure. The respondents were asked to estimate the risk of the various items to health on a rating scale of 1 to 5. 'Living near a nuclear plant' received the highest rating of 4, followed by 'not using solar UV protection in midsummer'. 'X-ray diagnostic tests' were rated at only 2, which was lower than the rating for 'air travel'. Among the respondents, undergraduate students showed the highest average risk rating across all items followed by nurses, and staff and graduate students, with doctors and dentists producing the lowest scores. These results suggest that level of specialist knowledge is associated with risk perception, and therefore that radiation education should be carefully planned to improve levels of understanding. (author)

Average annual doses, lifetime doses and associated risk of cancer death for radiation workers in various fuel fabrication facilities in India

International Nuclear Information System (INIS)

Iyer, P.S.; Dhond, R.V.

1980-01-01

Lifetime doses based on average annual doses are estimated for radiation workers in various fuel fabrication facilities in India. For such cumulative doses, the risk of radiation-induced cancer death is computed. The methodology for arriving at these estimates and the assumptions made are discussed. Based on personnel monitoring records from 1966 to 1978, the average annual dose equivalent for radiation workers is estimated as 0.9 mSv (90 mrem), and the maximum risk of cancer death associated with this occupational dose as 1.35x10 -5 a -1 , as compared with the risk of death due to natural causes of 7x10 -4 a -1 and the risk of death due to background radiation alone of 1.5x10 -5 a -1 . (author)

Estimation of radiation risks at low dose

International Nuclear Information System (INIS)

1990-04-01

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

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

Science.gov (United States)

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

2016-12-01

Strong evidence for the statistical association between radiation exposure and disease has been produced for thyroid cancer by epidemiological studies after the Chernobyl accident. However, limitations of the epidemiological approach in order to explore health risks especially at low doses of radiation appear obvious. Statistical fluctuations due to small case numbers dominate the uncertainty of risk estimates. Molecular radiation markers have been searched extensively to separate radiation-induced cancer cases from sporadic cases. The overexpression of the CLIP2 gene is the most promising of these markers. It was found in the majority of papillary thyroid cancers (PTCs) from young patients included in the Chernobyl tissue bank. Motivated by the CLIP2 findings we propose a mechanistic model which describes PTC development as a sequence of rate-limiting events in two distinct paths of CLIP2-associated and multistage carcinogenesis. It integrates molecular measurements of the dichotomous CLIP2 marker from 141 patients into the epidemiological risk analysis for about 13 000 subjects from the Ukrainian-American cohort which were exposed below age 19 years and were put under enhanced medical surveillance since 1998. For the first time, a radiation risk has been estimated solely from marker measurements. Cross checking with epidemiological estimates and model validation suggests that CLIP2 is a marker of high precision. CLIP2 leaves an imprint in the epidemiological incidence data which is typical for a driver gene. With the mechanistic model, we explore the impact of radiation on the molecular landscape of PTC. The model constitutes a unique interface between molecular biology and radiation epidemiology. © The Author 2016. Published by Oxford University Press.

Estimation of solar radiation from Australian meterological observations

International Nuclear Information System (INIS)

Moriarty, W.W.

1991-01-01

A carefully prepared set of Australian radiation and meteorological data was used to develop a system for estimating hourly or instantaneous broad band direct, diffuse and global radiation from meteorological observations. For clear sky conditions relationships developed elsewhere were adapted to Australian data. For cloudy conditions the clouds were divided into two groups, high clouds and opaque (middle and low) clouds, and corrections were made to compensate for the bias due to reporting practices for almost clear and almost overcast skies. Careful consideration was given to the decrease of visible sky toward the horizon caused by the vertical extent of opaque clouds. Equations relating cloud and other meteorological observations to the direct and diffuse radiation contained four unknown quantities, functions of cloud amount and of solar elevation, which were estimated from the data. These were the proportions of incident solar radiation passed on as direct and as diffuse radiation by high clouds, and as diffuse radiation by opaque clouds, and a factor to describe the elevation dependence of the fraction of sky not obscured by opaque clouds. When the resulting relationships were used to estimate global, direct and diffuse radiation on a horizontal surface, the results were good, especially for global radiation. Some discrepancies between estimates and measurements of diffuse and direct radiation were probably due to erroneously high measurements of diffuse radiation

Radiation. Doses, effect, risk

International Nuclear Information System (INIS)

Vapirev, E.; Todorov, P.

1994-12-01

This book outlines in a popular form the topic of ionizing radiation impacts on living organisms. It contains data gathered by ICRP for a period of 35 years. The essential dosimetry terms and units are presented. Natural and artificial sources of ionizing radiation are described. Possible biological radiation effects and diseases as a consequence of external and internal irradiation at normal and accidental conditions are considered. An assessment of genetic risk for human populations is presented and the concept of 'acceptable risk' is discussed

Risks of secondary malignancies with heterotopic bone radiation therapy for patients younger than 40 years

Energy Technology Data Exchange (ETDEWEB)

Cadieux, Catherine L., E-mail: ccadieux@umail.iu.edu [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); DesRosiers, Colleen [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); McMullen, Kevin [Department of Radiation Oncology, IU Health Methodist Hospital, Indianapolis, IN (United States)

2016-10-01

Heterotopic ossification (HO) of the bone is defined as a benign condition in which abnormal bone formation occurs in soft tissue. One of the most common prophylactic treatments for HO is radiation therapy (RT). This study retrospectively reviewed 20 patients younger than the age of 40 who received radiation to prevent HO in a single fraction of 7 Gray. The purpose of this study is to assess the risk of a second malignancy in these patients by recreating their treatment fields and contouring organs at risk to estimate the radiation dose absorbed by normal tissues outside the radiation treatment field. Diagnostic computed tomography (CT) scans for each patient were used to recreate treatment fields and to calculate dose to structures of interest. The distance from the field edge to each structure and its depth was recorded. Dose measurements in a water phantom were performed for the range of depths, distances, and field sizes used in the actual treatment plans. Computer-generated doses were compared to estimates based on measurement. The structure dose recorded was the higher dose generated between the 2 methods. Scatter dose was recorded to the rectum, bladder, sigmoid colon, small bowel, ovaries and utero-cervix in female patients, and prostate and gonads in male patients. In some patients, there is considerable dose received by certain organs from scatter because of their proximity to the radiation field. The average dose to the ovarian region was 4.125 Gy with a range of 1.085 to 6.228 Gy. The risk estimate for these patients ranged from 0.16% to 0.93%. The average total lifetime risk estimate for the bladder in all patients is 0.22% and the average total lifetime risk estimate for the remainder organs in all patients is 1.25%. In conclusions, proper shielding created from multileaf collimators (MLCs), blocks, and shields should always be used when possible.

Risks of secondary malignancies with heterotopic bone radiation therapy for patients younger than 40 years

International Nuclear Information System (INIS)

Cadieux, Catherine L.; DesRosiers, Colleen; McMullen, Kevin

2016-01-01

Heterotopic ossification (HO) of the bone is defined as a benign condition in which abnormal bone formation occurs in soft tissue. One of the most common prophylactic treatments for HO is radiation therapy (RT). This study retrospectively reviewed 20 patients younger than the age of 40 who received radiation to prevent HO in a single fraction of 7 Gray. The purpose of this study is to assess the risk of a second malignancy in these patients by recreating their treatment fields and contouring organs at risk to estimate the radiation dose absorbed by normal tissues outside the radiation treatment field. Diagnostic computed tomography (CT) scans for each patient were used to recreate treatment fields and to calculate dose to structures of interest. The distance from the field edge to each structure and its depth was recorded. Dose measurements in a water phantom were performed for the range of depths, distances, and field sizes used in the actual treatment plans. Computer-generated doses were compared to estimates based on measurement. The structure dose recorded was the higher dose generated between the 2 methods. Scatter dose was recorded to the rectum, bladder, sigmoid colon, small bowel, ovaries and utero-cervix in female patients, and prostate and gonads in male patients. In some patients, there is considerable dose received by certain organs from scatter because of their proximity to the radiation field. The average dose to the ovarian region was 4.125 Gy with a range of 1.085 to 6.228 Gy. The risk estimate for these patients ranged from 0.16% to 0.93%. The average total lifetime risk estimate for the bladder in all patients is 0.22% and the average total lifetime risk estimate for the remainder organs in all patients is 1.25%. In conclusions, proper shielding created from multileaf collimators (MLCs), blocks, and shields should always be used when possible.

Medical radiation exposure and genetic risks

International Nuclear Information System (INIS)

Baker, D.G.

1980-01-01

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%

Techniques for detecting and determining risks from low-level radiation

International Nuclear Information System (INIS)

Boice, J.D.

1980-01-01

Epidemiology is the study of disease in man. In evaluating radiation hazards, analytic studies have utilized the cohort type of investigation (where persons exposed and not exposed to radiation are followed forward in time for determination of disease experience) or case-control approaches (where persons with and without a specific disease are evaluated for previous exposure to radiation). Most radiation studies have evaluated cohorts (e.g., radiologists), although important case-control studies have been conducted (e.g., childhood leukemia as related to prenatal x ray). At its best, epidemiology is capable fo evaluating relative risks (RR) on the order of 1.4 (i.e., a 40% relative excess). However, the RRs of interest following low doses of radiation (1 rad) are on the order of 1.02-1.002. Thus, not much should be anticipated from direct observations at 1 rad, and indirect approaches must be taken to estimate low-dose effects. Such indirect approaches include evaluating 1) populations exposed to a range of doses, both low and high, where interpolation models can be reasonably applied to estimate low-dose effects; and 2) populations exposed to fractionated doses over a long period of time where the resulting dose-effect relationship theoretically should be linear and the estimation of low-level health effects facilitated

Joint Estimation of Cardiac Toxicity and Recurrence Risks After Comprehensive Nodal Photon Versus Proton Therapy for Breast Cancer

DEFF Research Database (Denmark)

Stick, Line B; Yu, Jen; Maraldo, Maja V

2017-01-01

PURPOSE: The study aims to perform joint estimation of the risk of recurrence caused by inadequate radiation dose coverage of lymph node targets and the risk of cardiac toxicity caused by radiation exposure to the heart. Delivered photon plans are compared with realistic proton plans, thereby pro...

Radiation effects on cancer risks in the life span study cohort

International Nuclear Information System (INIS)

Kodama, K.; Ozasa, K.; Katayama, H.; Shore, R. E.; Okubo, T.

2012-01-01

To determine late health effects of radiation in atomic bomb survivors, the Radiation Effects Research Foundation has been conducting studies on the Life Span Study (LSS) population, which consists of 93 000 atomic bomb survivors and 27.000 controls. A recent report on the incidence of solid cancers estimates that at the age of 70 y, after exposure at the age of 30 y, solid-cancer rates increase by about 35 % per Gy for men and 58 % per Gy for women. The age-at-exposure is an important risk modifier. Furthermore, it seems that radiation-associated increases in cancer rates persist throughout life. In addition, radiation has similar effects upon first-primary and second-primary cancer risks. A recent report on leukemia mortality suggested that the effect of radiation on leukemia mortality persisted for more than five decades. In addition, a significant dose-response for myelodysplastic syndrome is found in Nagasaki LSS members 40-60 y after radiation exposure. In view of the nature of the continuing increase in solid cancers, the LSS should continue to provide important new information on cancer risks, as most survivors still alive today were exposed to the atomic bomb radiation under the age of 20 y and are now entering their cancer-prone years. (authors)

Radiation Dose Assesment And Risk Estimation During Extracorporeal Shock Wave Lithotripsy

International Nuclear Information System (INIS)

Sulieman, A.; Ibrahim, A.A.; Osman, H.; Yousef, M.

2011-01-01

Extracorporeal shockwave lithotripsy (ESWL) is considered the gold standard for calculi fragmentation. The aims of this study are to measure the entrance surface dose (ESD) using thermo-luminescence dosimeter (TLDs) and to estimate the probability of carcinogenesis during ESWL procedure. The study was carried out at two centers (Group A, 50 patients) and (Group B, 25 patients). The mean ESD and effective doses were 36 mGy and 34 mSv. The results show that the probability of carcinogenesis is a tiny value 100 per million patients) but the main biological effect is occurring due to the accumulative impact of radiation.

Mammography and radiation risk; Mammographie und Strahlenrisiko

Energy Technology Data Exchange (ETDEWEB)

Jung, H. [Hamburg Univ. (Germany). Inst. fuer Biophysik und Strahlenbiologie

1998-10-01

Breast cancer is the most frequent malignant neoplasia among women in Germany. The use of mammography as the most relevant diagnostic procedure has increased rapidly over the last decade. Radiation risks associated with mammography may be estimated from the results of numerous epidemiological studies providing risk coefficients for breast cancer in relation to age at exposure. Various calculations can be performed using the risk coefficients. For instance, a single mammography examination (bilateral, two views of each breast) of a women aged 45 may enhance the risk of developing breast cancer during her lifetime numerically from about 12% of 12.0036%. This increase in risk is lower by a factor of 3,300 as compared to the risk of developing breast cancer in the absence of radiation exposure. At the age of 40 or more, the benefit of mammography exceeds the radiation risk by a factor of about 100. At higher ages this factor increases further. Finally, the dualism of individual risk and collective risk is considered. It is shown that the individual risk of a patient, even after multiple mammography examinations, is vanishingly small. Nevertheless, the basic principle of minimising radiation exposure must be followed to keep the collective risk in the total population as low as reasonably achievable. (orig.) [Deutsch] Das Mammakarzinom ist in Deutschland die haeufigste Krebserkrankung der Frau, und entsprechend oft wird die Mammographie als das derzeit wichtigste Diagnoseverfahren eingesetzt. Zur Beurteilung des mit einer mammographischen Untersuchung verbundenen Strahlenrisikos liegen die Resultate einer groesseren Anzahl strahlenepidemiologischer Studien vor. Diese liefern den Risikokoeffizienten fuer Brustkrebs in Abhaengigkeit vom Lebensalter bei Strahlenexposition und ermoeglichen somit die Berechnung des altersabhaengigen Strahlenrisikos. Beispielsweise wird durch eine einmalige Mammographie-Untersuchung (bilateral, je zwei Aufnahmen in zwei Ebenen) bei einer 45

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

Energy Technology Data Exchange (ETDEWEB)

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

2000-10-01

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

Epidemiological methods of assessing risks from low level occupational exposure to ionising radiation

International Nuclear Information System (INIS)

Reissland, J.A.

1982-01-01

The resolution of radiation-attributable malignancies from the background of malignancies which are responsible for about 20% of all deaths in the Western world, presents a formidable challenge to epidemiological methods. Some of the major difficulties facing those with the task of estimating the risks associated with exposure to low level ionising radiation are discussed, particularly in the context of radiological protection. Some of the studies currently in progress are summarised and suggestions are made for other work which may help to contribute to a better understanding of the quantitative aspects of radiation risk assessment. (author)

Perception of risk from radiation

International Nuclear Information System (INIS)

Slovic, P.

1996-01-01

Perceptions of risk from radiation have been studied systematically for about 20 years. This paper summarises the key findings and conclusions from this research with regard to the nature of risk perceptions, the impacts of these perceptions, and the need for communication about radiological hazards. Perhaps the most important generalisation from research in this area is that there is no uniform or consistent perception of radiation risks. Public perception and acceptance is determined by the context in which the radiation is used -and the very different reactions to different uses provide insight into the nature of perception and the determinants of acceptable risk. (author)

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

Directory of Open Access Journals (Sweden)

Smith Jim T

2007-04-01

Full Text Available Abstract 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.

Risk concepts in various fields including radiation protection. A historical review and some recent topics

International Nuclear Information System (INIS)

Kai, Michiaki

2000-01-01

This is a review by the expert group concerning risks in radiation protection and in chemical management, recent state of protection and of health-risk assessment of low dose radiation, and risk concepts in other fields. Risk concepts in radiation protection are described mainly on ICRP: Its history leading to its Publication 1 (1958), Pub. 9 (1965), Pub. 26 (1977) and Pub. 60 (1990). In that recent publication, the term, risk, is used only for the established one like estimated risk or excess relative risk. Risk management of chemicals involves that against pollution from environmental and ecological aspects, and assessment of dioxin and chemicals from toxicology and carcinogenicity aspects. Recently, risks of low dose radiation have been actively discussed conceivably because of possible reduction of the exposure limit in ICRP Recommendation 1990, Chernobyl accident, advances of radiation biology and radiation protection problem in the radioactive waste disposition. Globally, many academic societies such as American Health-Physics Society published Position Statements and Reports and there are activities like the Research program plan for the risk and an international conference of bridging radiation policy and science. Risk concepts involve technological and ecological ones, insurance ones and health ones. Risk assessment or analysis is done through recognition, measurement and prediction, thus through the scientific process based on objective facts. (K.H.)

Modifying EPA radiation risk models based on BEIR VII

International Nuclear Information System (INIS)

Pawel, D.; Puskin, J.

2007-01-01

This paper summarizes a 'draft White Paper' that provides details on proposed changes in EPA's methodology for estimating radiogenic cancer risks. Many of the changes are based on the contents of a recent National Academy of Sciences (NAS) report (BEIR VII), that addresses cancer and genetic risks from low doses of low-LET radiation. The draft White Paper was prepared for a meeting with the EPA's Science Advisory Board's Radiation Advisory Committee (RAC) in September for seeking advice on the application of BEIR VII and on issues relating to these modifications and expansions. After receiving the Advisory review, we plan to implement the changes by publishing the new methodology in an EPA report, which we expect to submit to the RAC for final review. The revised methodology could then be applied to update the cancer risk coefficients for over 800 radionuclides that are published in EPA's Federal Guidance Report 13. (author)

Individual-based model for radiation risk assessment

Science.gov (United States)

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.

Risk management of radiation therapy. Survey by north Japan radiation therapy oncology group

International Nuclear Information System (INIS)

Aoki, Masahiko; Abe, Yoshinao; Yamada, Shogo; Hareyama, Masato; Nakamura, Ryuji; Sugita, Tadashi; Miyano, Takashi

2004-01-01

A North Japan Radiation Oncology Group (NJRTOG) survey was carried out to disclose the risk management of radiation therapy. During April 2002, we sent questionnaires to radiation therapy facilities in northern Japan. There were 31 replies from 27 facilities. Many incidents and accidents were reported, including old cases. Although 60% of facilities had a risk management manual and/or risk manager, only 20% had risk management manuals for radiation therapy. Eighty five percent of radiation oncologists thought that incidents may be due to a lack of manpower. Ninety percent of radiation oncologists want to know the type of cases happened in other facilities. The risk management system is still insufficient for radiation therapy. We hope that our data will be a great help to develop risk management strategies for radiation therapy for all radiation oncologists in Japan. (author)

Radiation risk in space exploration

International Nuclear Information System (INIS)

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

1997-01-01

Humans living and working in space are exposed to energetic charged particle radiation due to galactic cosmic rays and solar particle emissions. In order to keep the risk due to radiation exposure of astronauts below acceptable levels, the physical interaction of these particles with space structures and the biological consequences for crew members need to be understood. Such knowledge is, to a large extent, very sparse when it is available at all. Radiation limits established for space radiation protection purposes are based on extrapolation of risk from Japanese survivor data, and have been found to have large uncertainties. In space, attempting to account for large uncertainties by worst-case design results in excessive costs and accurate risk prediction is essential. It is best developed at ground-based laboratories, using particle accelerator beams to simulate individual components of space radiation. Development of mechanistic models of the action of space radiation is expected to lead to the required improvements in the accuracy of predictions, to optimization of space structures for radiation protection and, eventually, to the development of biological methods of prevention and intervention against radiation injury. (author)

Fire simulation in radioactive waste disposal and the radiation risk associated

International Nuclear Information System (INIS)

Domingos, Érica Nascimento

2018-01-01

An atmospheric dispersion of radioactive material is one of the possible consequences of an accident scenario in nuclear installations, radiative and radioactive waste deposit. Taking into account a possibility of this release of radioactive material into the atmosphere this work proposes a modeling of the atmospheric dispersion from a fire scenario in a deposit of radioactive waste of low and middle level of radiation varying the amount of inventory released in the fire. For this simulation was adopted the software of physical codes of medical health, the HotSpot Health Physics Codes which uses the Gaussian model to calculate an atmospheric dispersion based on the Pasquill atmospheric stability classes. This software calculates a total effective dose in relation to distance, such as a compromised dose in a list of specific organs, among them the lung, object of work study for calculating the risk of cancer associated with a low dose of radiation. The radiological risk calculation is held by the BEIR V model, Biological Effects of Ionizing Radiations, one of the models to estimate the relative risk of cancer induced by ionizing radiation. (author)

Model-free approach to the estimation of radiation hazards. I. Theory

International Nuclear Information System (INIS)

Zaider, M.; Brenner, D.J.

1986-01-01

The experience of the Japanese atomic bomb survivors constitutes to date the major data base for evaluating the effects of low doses of ionizing radiation on human populations. Although numerous analyses have been performed and published concerning this experience, it is clear that no consensus has emerged as to the conclusions that may be drawn to assist in setting realistic radiation protection guidelines. In part this is an inherent consequences of the rather limited amount of data available. In this paper the authors address an equally important problem; namely, the use of arbitrary parametric risk models which have little theoretical foundation, yet almost totally determine the final conclusions drawn. They propose the use of a model-free approach to the estimation of radiation hazards

Generalized indices for radiation risk analysis

International Nuclear Information System (INIS)

Bykov, A.A.; Demin, V.F.

1989-01-01

A new approach to ensuring nuclear safety has begun forming since the early eighties. The approach based on the probabilistic safety analysis, the principles of acceptable risk, the optimization of safety measures, etc. has forced a complex of adequate quantitative methods of assessment, safety analysis and risk management to be developed. The method of radiation risk assessment and analysis hold a prominent place in the complex. National and international research and regulatory organizations ICRP, IAEA, WHO, UNSCEAR, OECD/NEA have given much attention to the development of the conceptual and methodological basis of those methods. Some resolutions of the National Commission of Radiological Protection (NCRP) and the Problem Commission on Radiation Hygiene of the USSR Ministry of Health should be also noted. Both CBA (cost benefit analysis) and other methods of radiation risk analysis and safety management use a system of natural and socio-economic indices characterizing the radiation risk or damage. There exist a number of problems associated with the introduction, justification and use of these indices. For example, the price, a, of radiation damage, or collective dose unit, is a noteworthy index. The difficulties in its qualitative and quantitative determination are still an obstacle for a wide application of CBA to the radiation risk analysis and management. During recent 10-15 years these problems have been a subject of consideration for many authors. The present paper also considers the issues of the qualitative and quantitative justification of the indices of radiation risk analysis

The estimation of risks from the induction of recessive mutations after exposure to ionising radiation

International Nuclear Information System (INIS)

Searle, A.G.; Edwards, J.H.

1986-01-01

Induced recessive mutations can cause harm by (1) partnership with a defective allele already established in the population; (2) partnership with another recessive mutation induced at the same locus; (3) the formation of homozygous descendants, that is, identify by descent; and (4) heterozygous effects. Calculations based on a combination of data from observations on human populations and from mouse experiments suggest that an extra genetically significant dose of 1 cGy X or γ irradiation received by each parent in a stable population with a million liveborn offspring would induce up to 1200 extra recessive mutations. From partnership effects, about one extra case of recessive disease would be expected in the following 10 generations. Homozygosity resulting from identity by descent could not normally occur until the fourth generation after exposure but, on certain assumptions, about ten extra cases of recessive disease would be expected from this cause by the tenth generation. In the same period, about 250 recessive alleles would be eliminated in heterozygotes given 2.5% heterozygous disadvantage. These deleterious heterozygous effects should not be combined with those of dominants, as has been done in some previous risk estimates. It is considered unlikely that many radiation induced recessives would show heterozygous advantage. Certain dominants should be excluded from calculations of mutational risk because they are unlikely to be maintained by mutation. (author)

Observationally constrained estimates of carbonaceous aerosol radiative forcing.

Science.gov (United States)

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

2012-07-17

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

Female gonadal shielding with automatic exposure control increases radiation risks

Energy Technology Data Exchange (ETDEWEB)

Kaplan, Summer L.; Zhu, Xiaowei [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA (United States); Magill, Dennise; Felice, Marc A. [University of Pennsylvania, Environmental Health and Radiation Safety, Philadelphia, PA (United States); Xiao, Rui [University of Pennsylvania, Department of Biostatistics and Epidemiology, Philadelphia, PA (United States); Ali, Sayed [Temple University Hospital, Department of Radiology, Philadelphia, PA (United States)

2018-02-15

Gonadal shielding remains common, but current estimates of gonadal radiation risk are lower than estimated risks to colon and stomach. A female gonadal shield may attenuate active automatic exposure control (AEC) sensors, resulting in increased dose to colon and stomach as well as to ovaries outside the shielded area. We assess changes in dose-area product (DAP) and absorbed organ dose when female gonadal shielding is used with AEC for pelvis radiography. We imaged adult and 5-year-old equivalent dosimetry phantoms using pelvis radiograph technique with AEC in the presence and absence of a female gonadal shield. We recorded DAP and mAs and measured organ absorbed dose at six internal sites using film dosimetry. Female gonadal shielding with AEC increased DAP 63% for the 5-year-old phantom and 147% for the adult phantom. Absorbed organ dose at unshielded locations of colon, stomach and ovaries increased 21-51% in the 5-year-old phantom and 17-100% in the adult phantom. Absorbed organ dose sampled under the shield decreased 67% in the 5-year-old phantom and 16% in the adult phantom. Female gonadal shielding combined with AEC during pelvic radiography increases absorbed dose to organs with greater radiation sensitivity and to unshielded ovaries. Difficulty in proper use of gonadal shields has been well described, and use of female gonadal shielding may be inadvisable given the risks of increasing radiation. (orig.)

Female gonadal shielding with automatic exposure control increases radiation risks

International Nuclear Information System (INIS)

Kaplan, Summer L.; Zhu, Xiaowei; Magill, Dennise; Felice, Marc A.; Xiao, Rui; Ali, Sayed

2018-01-01

Gonadal shielding remains common, but current estimates of gonadal radiation risk are lower than estimated risks to colon and stomach. A female gonadal shield may attenuate active automatic exposure control (AEC) sensors, resulting in increased dose to colon and stomach as well as to ovaries outside the shielded area. We assess changes in dose-area product (DAP) and absorbed organ dose when female gonadal shielding is used with AEC for pelvis radiography. We imaged adult and 5-year-old equivalent dosimetry phantoms using pelvis radiograph technique with AEC in the presence and absence of a female gonadal shield. We recorded DAP and mAs and measured organ absorbed dose at six internal sites using film dosimetry. Female gonadal shielding with AEC increased DAP 63% for the 5-year-old phantom and 147% for the adult phantom. Absorbed organ dose at unshielded locations of colon, stomach and ovaries increased 21-51% in the 5-year-old phantom and 17-100% in the adult phantom. Absorbed organ dose sampled under the shield decreased 67% in the 5-year-old phantom and 16% in the adult phantom. Female gonadal shielding combined with AEC during pelvic radiography increases absorbed dose to organs with greater radiation sensitivity and to unshielded ovaries. Difficulty in proper use of gonadal shields has been well described, and use of female gonadal shielding may be inadvisable given the risks of increasing radiation. (orig.)

Female gonadal shielding with automatic exposure control increases radiation risks.

Science.gov (United States)

Kaplan, Summer L; Magill, Dennise; Felice, Marc A; Xiao, Rui; Ali, Sayed; Zhu, Xiaowei

2018-02-01

Gonadal shielding remains common, but current estimates of gonadal radiation risk are lower than estimated risks to colon and stomach. A female gonadal shield may attenuate active automatic exposure control (AEC) sensors, resulting in increased dose to colon and stomach as well as to ovaries outside the shielded area. We assess changes in dose-area product (DAP) and absorbed organ dose when female gonadal shielding is used with AEC for pelvis radiography. We imaged adult and 5-year-old equivalent dosimetry phantoms using pelvis radiograph technique with AEC in the presence and absence of a female gonadal shield. We recorded DAP and mAs and measured organ absorbed dose at six internal sites using film dosimetry. Female gonadal shielding with AEC increased DAP 63% for the 5-year-old phantom and 147% for the adult phantom. Absorbed organ dose at unshielded locations of colon, stomach and ovaries increased 21-51% in the 5-year-old phantom and 17-100% in the adult phantom. Absorbed organ dose sampled under the shield decreased 67% in the 5-year-old phantom and 16% in the adult phantom. Female gonadal shielding combined with AEC during pelvic radiography increases absorbed dose to organs with greater radiation sensitivity and to unshielded ovaries. Difficulty in proper use of gonadal shields has been well described, and use of female gonadal shielding may be inadvisable given the risks of increasing radiation.

Estimated radiation doses to different organs among patients treated for ankylosing spondylitis with a single course of X rays

International Nuclear Information System (INIS)

Lewis, C.A.; Smith, P.G.; Stratton, I.M.; Darby, S.C.; Doll, R.

1988-01-01

A follow-up study of over 14000 patients treated with a single course of X rays for ankylosing spondylitis demonstrated substantial excess risk of developing cancer. Previously the excess risk of leukaemia has been related to the estimated mean radiation dose to active bone marrow but detailed estimates were not made of the radiation doses to other organs. Data extracted from the original treatment records of a random sample of one in 15 patients have been used to make dose estimates, using Monte Carlo methods, for 30 specific organs or body regions and 12 bone marrow sites. Estimates of mean and median organ doses, standard deviations and ranges have been tabulated. Detailed distributions are presented for six organs (lung, bronchi, stomach, oesophagus, active bone marrow and total body). Comparison with the earlier bone marrow estimates and more recent theoretical estimates shows good agreement. (author)

Dose estimation for space radiation protection

International Nuclear Information System (INIS)

Xu Feng; Xu Zhenhua; Huang Zengxin; Jia Xianghong

2007-01-01

For evaluating the effect of space radiation on human health, the dose was estimated using the models of space radiation environment, models of distribution of the spacecraft's or space suit's mass thickness and models of human body. The article describes these models and calculation methods. (authors)

Radiation risk of diagnostical procedures

International Nuclear Information System (INIS)

Pohlit, W.

1986-01-01

The environmental radiation burden of man in Germany is about 1 mGy (Milligray) per year. This is, of course, also valid for children. Due to diagnostical procedures this burden is increased to about 1.3 mGy. The question arises wether this can be neglected, or important consequences have to be drawn. To give a clear answer, the action of ionizing radiation in living cells and in organisms is explained in detail. Many of the radiation actions at the DNA can soon be repaired by the cell, if the radiation dose was small. Some damage, however will remain irreparable for the cell and consequently leads to cell death, to mutations or to cell transformation. The number of these lesion increases or decreases linearily with radiation dose. Therefore, it must be expected that the risk of tumour induction is increased to above the normal background even by the smallest doses. This small but not negligible risk has to be compared with other risks of civilization or with other medical risks. But also the benefit and the efficacy of diagnostic procedures have to be considered. (orig./HSCH) [de

Estimation of radiation losses from sheathed thermocouples

International Nuclear Information System (INIS)

Roberts, I.L.; Coney, J.E.R.; Gibbs, B.M.

2011-01-01

Thermocouples are often used for temperature measurements in heat exchangers. However if the radiation losses from a thermocouple in a high temperature gas flow to colder surroundings are ignored significant errors can occur. Even at moderate temperature differences, these can be significant. Prediction of radiation losses from theory can be problematic, especially in situations where there are large variations in the measured temperatures as the emissivity and radiative heat transfer coefficient of the thermocouple are not constant. The following approach combines experimental results with established empirical relationships to estimate losses due to radiation in an annular heat exchanger at temperatures up to 950 o C. - Highlights: → Sheathed thermocouples are often used to measure temperatures in heat exchangers. → Errors are introduced if radiation losses are ignored. → Radiation losses are environment specific and may be significant. → Experimental and theoretical methods are used to estimate losses. → Hot side maximum temperature 950 o C.

Report on a workshop to examine methods to arrive at risk estimates for radiation-induced cancer in the human based on laboratory data. Jointly sponsored by the Office of Health and Energy Research, Department of Energy, and Columbia University.

Science.gov (United States)

1993-09-01

This summary is a record of discussions and the general consensus reached by the participants. The views expressed are those of the attending scientists and do not necessarily represent the policy or opinion of the Department of Energy. An urgent need is recognized for better estimates of the risk of cancer from low levels of radiation. This need arises because of the ongoing nuclear energy option, the hazard of naturally occurring radon, and the possibility of an increasing number of lawsuits by individuals exposed to radiation in the past. The most recent estimates of risk evaluated by UN-SCEAR and BEIR V rely heavily on epidemiological studies of the A-bomb survivors which have recognized limitations and cannot provide direct risk information for chronic low-dose-rate exposure such as that experienced in occupational and medical settings. It was the consensus view that an effort to obtain information relative to risk estimates for radiation-induced cancer in humans, based on laboratory data, would be both important and timely: important, because of the opportunity to extend existing epidemiological data and overcome existing limitations; and timely, because of advances in cellular and molecular biology. In the short term, such an effort could supplement epidemiological data by providing information on the variation of cancer risk estimates with radiation dose rate and radiation quality and by providing guidance on the extrapolation of data measured at high doses to low dose regions where direct measurements are not feasible. In the long term, it may be possible to use new information about the genome from cellular and molecular studies to refine epidemiological data, i.e., to integrate classical epidemiological approaches with cell and animal biology as well as molecular genetics. Laboratory-based studies may be able to supplement epidemiological studies by: (1) identifying the molecular lesions involved in radiation-induced cancer and resolving dose, dose

Radiation protection in space

Energy Technology Data Exchange (ETDEWEB)

Blakely, E.A. [Lawrence Berkeley Lab., CA (United States); Fry, R.J.M. [Oak Ridge National Lab., TN (United States)

1995-02-01

The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in the present state of knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared to previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space.

Radiation protection in space

International Nuclear Information System (INIS)

Blakely, E.A.; Fry, R.J.M.

1995-01-01

The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in the present state of knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared to previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space

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

Science.gov (United States)

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

2015-09-01

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

The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry

DEFF Research Database (Denmark)

Cardis, E; Vrijheid, M; Blettner, M

2007-01-01

A 15-Country collaborative cohort study was conducted to provide direct estimates of cancer risk following protracted low doses of ionizing radiation. Analyses included 407,391 nuclear industry workers monitored individually for external radiation and 5.2 million person-years of follow-up. A sign...

Whole body [{sup 11}C]-dihydrotetrabenazine imaging of baboons: biodistribution and human radiation dosimetry estimates

Energy Technology Data Exchange (ETDEWEB)

Murthy, Rajan [Columbia University College of Physicians and Surgeons, Department of Psychiatry, New York, NY (United States); New York State Psychiatric Institute, Department of Neuroscience, Division of Brain Imaging, New York, NY (United States); Harris, Paul; Leibel, Rudolph [Columbia University College of Physicians and Surgeons, Department of Medicine, New York, NY (United States); Simpson, Norman; Parsey, Ramin [Columbia University College of Physicians and Surgeons, Department of Psychiatry, New York, NY (United States); Van Heertum, Ronald [Columbia University College of Physicians and Surgeons, Department of Radiology, New York, NY (United States); New York State Psychiatric Institute, Department of Neuroscience, Division of Brain Imaging, New York, NY (United States); Mann, J.J. [Columbia University College of Physicians and Surgeons, Department of Psychiatry, New York, NY (United States); Columbia University College of Physicians and Surgeons, Department of Radiology, New York, NY (United States); New York State Psychiatric Institute, Department of Neuroscience, Division of Brain Imaging, New York, NY (United States)

2008-04-15

Vesicular monoamine transporter type 2 abundance quantified using the radiotracer [{sup 11}C]-dihydrotetrabenazine (DTBZ) has been used to study diagnosis and pathogenesis of dementia and psychiatric disorders in humans. In addition, it may be a surrogate marker for insulin-producing pancreatic beta cell mass, useful for longitudinal measurements using positron emission tomography to track progression of autoimmune diabetes. To support the feasibility of long-term repeated administrations, we estimate the biodistribution and dosimetry of [{sup 11}C]-DTBZ in humans. Five baboon studies were acquired using a Siemens ECAT camera. After transmission scanning, 165-210 MBq of [{sup 11}C]-DTBZ were injected, and dynamic whole body emission scans were conducted. Time-activity data were used to obtain residence times and estimate absorbed radiation dose according to the MIRD model. Most of the injected tracer localized to the liver and the lungs, followed by the intestines, brain, and kidneys. The highest estimated absorbed radiation dose was in the stomach wall. The largest radiation dose from [{sup 11}C]-DTBZ is to the stomach wall. This dose estimate, as well as the radiation dose to other radiosensitive organs, must be considered in evaluating the risks of multiple administrations. (orig.)

NEW MODEL FOR SOLAR RADIATION ESTIMATION FROM ...

African Journals Online (AJOL)

NEW MODEL FOR SOLAR RADIATION ESTIMATION FROM MEASURED AIR TEMPERATURE AND ... Nigerian Journal of Technology ... Solar radiation measurement is not sufficient in Nigeria for various reasons such as maintenance and ...

Risk equivalent of exposure versus dose of radiation

International Nuclear Information System (INIS)

Bond, V.P.

1986-01-01

Radiation is perhaps unique among all agents of interest in the Health Sciences in that it alone is both a therapeutic agent for the control of cancer and an essentially ubiquitous environmental agent with a potential for increasing the cancer rate in human populations. Therapy of tumors is accomplished with the high-level exposure (HLE) to radiation in order to effect control or a cure. Thus, it conforms to the concepts and approaches of pharmacology, toxicology, and therapeutic medicine. Only one function, that which relates the object-oriented and nonstochastic independent variable organ dose to its effect on a cancer or an organ, is needed to estimate the probability, P 2 , of a quantal response. Only P 2 is needed because P 1 , that the cancer slated for such treatment will receive some amount of the agent and be affected to some degree, is effectively unity. The health problem involving low-level exposure (LLE) to radiation, in contrast, is not at all analogous to those of pharmacology, toxicology, and medicine. Rather, it presents a public health problem in that it is a health population, albeit of cells, that is exposed in a radiation field composed of moving radiation particles with some attendant low-order carcinogenic or mutagenic risk. Thus, the concepts, quantities, and terminology applied to low-level radiation must be modified from their present orientation toward pharmacology, toxicology, medicine, and dose to conform to those of public health and accident statistics, in which both P 1 and P 2 for the exposed cells must be estimated

Interest and limits of epidemiology for the evaluation of radiation induced cancer risks and the setting up of radiation protection standards

International Nuclear Information System (INIS)

Hubert, D.

1990-01-01

Epidemiological studies allow to confirm that a risk does exist for some types of cancer following high-dose exposures often at high dose-rates. However, no conclusion can be drawn for low doses and low dose-rates. Therefore we have to extrapolate from known high-dose risks to low doses and low dose-rates by various dose-response patterns. Another difficulty in assessing radiation cancer risks comes from the long latency time, which explains that all excess cancers have not yet been observed in the irradiated population studied. Once more, mathematical models are used to project excess lifetime cancer mortality. The estimations of radiation cancer risks are therefore marked by a great number of uncertainties, since they change accordingly to the model used. Other uncertainties come from the data, especially the dose estimates and are heightened when extrapolating to other populations. In 1988, UNSCEAR assessed new estimates for excess lifetime cancer mortality in the range of 4 to 11% per gray. These values mean a revaluation of the previous estimates by a 1.6 to 4.4 factor, which is mainly consecutive to the use of different projection models. Besides, they are solely based on the Hiroshima and Nagasaki survivors, whereas patient studies assess a lower risk. Finally UNSCEAR does not precisely state what is the available reduction factor to modify risks for low doses and low dose rates which should lie between 2 and 10. Due to a number of persistent uncertainties, we should not consider it justified to revise protection standards presently. 9 tabs.; 45 refs [fr

Interests and limits of epidemiology for the evaluation of risks of radiation induced cancer and the establishing of radiation protection standards

International Nuclear Information System (INIS)

Hubert, D.

1991-04-01

Epidemiological studies allow to confirm that a risk does exist for some types of cancer following high-dose exposures often at high dose-rates. However, no conclusion can be drawn for low doses and low dose-rates. Therefore we have to extrapolate from known high-dose risks to low doses and low dose-rates by various dose-response patterns. Another difficulty in assessing radiation cancer risks comes from the long latency time, which explains that all excess cancers have not yet been observed in the irradiated population studied. Once more, mathematical models are used to project excess lifetime cancer mortality. The estimations of radiation cancer risks are therefore marked by a great number of uncertainties, since they change accordingly to the model used. Other uncertainties come from the data, especially the dose estimates and are heightened when extrapolating to other populations. In 1988, UNSCEAR assessed new estimates for excess lifetime cancer mortality in the range of 4 to 11% per gray. These values mean a revaluation of the previous estimates by a 1.6 to 4.4 factor, which is mainly consecutive to the use of different projection models. Besides, they are solely based on the Hiroshima and Nagasaki survivors, whereas patient studies assess a lower risk. Finally UNSCEAR does not precisely state what is the available reduction factor to modify risks for low doses and low dose rates which should lie between 2 and 10. Due to a number of persistent uncertainties, we should not consider it justified to revise protection standards presently. (author)

Cardiovascular event-free survival after adjuvant radiation therapy in breast cancer patients stratified by cardiovascular risk

International Nuclear Information System (INIS)

Onwudiwe, Nneka C; Kwok, Young; Onukwugha, Eberechukwu; Sorkin, John D; Zuckerman, Ilene H; Shaya, Fadia T; Daniel Mullins, C

2014-01-01

The objective of this study was to estimate the risk of a cardiovascular event or death associated with modern radiation in a population of elderly female breast cancer patients with varying baseline cardiovascular risk. The data used for this analysis are from the linked Surveillance, Epidemiology, and End-Results (SEER)-Medicare database. The retrospective cohort study included women aged 66 years and older with stage 0–III breast cancer diagnosed between 2000 and 2005. Women were grouped as low, intermediate, or high cardiovascular risk based on the presence of certain clinical diagnoses. The risk for the combined outcome of a hospitalization for a cardiovascular event or death within 6 months and 24 months of diagnosis was estimated using a multivariable Cox model. The median follow-up time was 24 months. Among the 91,612 women with American Joint Committee on Cancer (AJCC) stage 0–III breast cancer: 39,555 (43.2%) were treated with radiation therapy and 52,057 (56.8%) were not. The receipt of radiation therapy in the first 6 months was associated with a statistically significant increased risk for the combined outcome in women categorized as high risk (HR = 1.510; 95% CI, 1.396–1.634) or intermediate risk (HR = 1.415; 95% CI, 1.188–1.686) but not low risk (HR = 1.027; 95% CI, 0.798–1.321). Women with a prior medical history of cardiovascular disease treated with radiation therapy are at increased risk for an event and should be monitored for at least 6 months following treatment with radiation therapy

Some concepts, terminology, and methodology for radiation risk assessment

International Nuclear Information System (INIS)

Groer, P.G.; Barlow, R.E.

1982-01-01

The controversy concerning cancer risk estimates for human populations exposed to low doses of ionizing radiations is discussed. The authors note that while little can be done to obtain more and better data on human populations, the analysis of available data can be sharpened through the consistent use of appropriate statistical techniques. Some probabilistic concepts that will help to define ''dose-response curve'' are given

Exposure to diagnostic radiation and risk of breast cancer among carriers of BRCA1/2 mutations: retrospective cohort study (GENE-RAD-RISK)

NARCIS (Netherlands)

Pijpe, Anouk; Andrieu, Nadine; Easton, Douglas F.; Kesminiene, Ausrele; Cardis, Elisabeth; Noguès, Catherine; Gauthier-Villars, Marion; Lasset, Christine; Fricker, Jean-Pierre; Peock, Susan; Frost, Debra; Evans, D. Gareth; Eeles, Rosalind A.; Paterson, Joan; Manders, Peggy; van Asperen, Christi J.; Ausems, Margreet G. E. M.; Meijers-Heijboer, Hanne; Thierry-Chef, Isabelle; Hauptmann, Michael; Goldgar, David; Rookus, Matti A.; van Leeuwen, Flora E.; Fourme, Emmanuelle; Lidereau, Rosette; Stevens, Denise; Stoppa-Lyonnet, Dominique; Chompret, Agnès; Berthet, Pascaline; Luporsi, Elisabeth; Bonadona, Valérie; Gauducheau, René; de Sienne, Catherine; Lortholary, Alain; Frénay, Marc; Faivre, Laurence; Sobol, Hagay; Huiart, Laetitia; Longy, Michel; Nguyen, Tan Dat; Gladieff, Laurence; Guimbaud, Rosine; Gesta, Paul; Vennin, Philippe; Adenis, Claude; Chevrier, Annie; Rossi, Annick; Perrin, Jean; Bignon, Yves-Jean; Limacher, Jean-Marc; Dugast, Catherine; Courlancy, Polyclinique; Demange, Liliane; Zattara-Cannoni, Hélène; Dreyfus, Hélène; Noruzinia, Mehrdad; Venat-Bouvet, Laurence; Cook, Margaret; Oliver, Clare; Gregory, Helen; Cole, Trevor; Burgess, Lucy; Rogers, Mark; Hughes, Lisa; Brewer, Carole; Davidson, Rosemarie; Bradshaw, Nicola; Izatt, Louise; Pichert, Gabriella; Langman, Caroline; Chu, Carol; Miller, Julie; Evans, Gareth; Lalloo, Fiona; Shenton, Andrew; Side, Lucy; Bancroft, Elizabeth; Page, Elizabeth; Castro, Elena; Houlston, Richard; Rahman, Nazneen; Shanley, Susan; Cook, Jackie; Baxter, Lauren; Hodgson, Shirley; Goff, Sheila; Eccles, Diana; Verhoef, Senno; Brohet, Richard; Hogervorst, Frans; van 't Veer, Laura; van Leeuwen, Flora; Rookus, Matti; Collée, Margriet; van den Ouweland, Ans; Kriege, Mieke; Schutte, Mieke; Hooning, Maartje; Seynaeve, Caroline; Tollenaar, Rob; van Asperen, Christi; Wijnen, Juul; Devilee, Peter; Ligtenberg, Marjolijn; Ausems, Margreet; van der Luijt, Rob; Aalfs, Cora; van Os, Theo; Gille, Hans; Gomez-Garcia, Encarna; Blok, Rien; Oosterwijk, Jan; van der Hout, Annemiek; Vasen, Hans; van Leeuwen, Inge

2012-01-01

To estimate the risk of breast cancer associated with diagnostic radiation in carriers of BRCA1/2 mutations. Retrospective cohort study (GENE-RAD-RISK). Three nationwide studies (GENEPSO, EMBRACE, HEBON) in France, United Kingdom, and the Netherlands, 1993 female carriers of BRCA1/2 mutations

Understanding and characterisation of the risks to human health from exposure to low levels of radiation

International Nuclear Information System (INIS)

Goodhead, D. T.

2009-01-01

Exposure to ionising radiation can lead to a wide variety of health effects. Cancer is judged to be the main risk from radiation at low doses and low dose rates, and controlling this risk has been the main factor in developing radiation protection practice. Conventional paradigms of radiobiology and radiation carcinogenesis have served to guide extrapolations of epidemiological data on exposed human populations, so as to estimate risks at low doses and low dose rates, to other types of ionising radiation and to non-uniform exposures. These paradigms are founded on a century of experimental and theoretical studies, but nevertheless there remain many uncertainties. Major assumptions and simplifications have been introduced to achieve a practical system of additive doses (and implied risks) for radiation protection. Advancing epidemiological studies and experimental research continue to reduce uncertainties in some areas while, in others, they raise new challenges to the generality and applicability of the conventional paradigms. (authors)

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

Science.gov (United States)

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.

Data error effects on net radiation and evapotranspiration estimation

International Nuclear Information System (INIS)

Llasat, M.C.; Snyder, R.L.

1998-01-01

The objective of this paper is to evaluate the potential error in estimating the net radiation and reference evapotranspiration resulting from errors in the measurement or estimation of weather parameters. A methodology for estimating the net radiation using hourly weather variables measured at a typical agrometeorological station (e.g., solar radiation, temperature and relative humidity) is presented. Then the error propagation analysis is made for net radiation and for reference evapotranspiration. Data from the Raimat weather station, which is located in the Catalonia region of Spain, are used to illustrate the error relationships. The results show that temperature, relative humidity and cloud cover errors have little effect on the net radiation or reference evapotranspiration. A 5°C error in estimating surface temperature leads to errors as big as 30 W m −2 at high temperature. A 4% solar radiation (R s ) error can cause a net radiation error as big as 26 W m −2 when R s ≈ 1000 W m −2 . However, the error is less when cloud cover is calculated as a function of the solar radiation. The absolute error in reference evapotranspiration (ET o ) equals the product of the net radiation error and the radiation term weighting factor [W = Δ(Δ1+γ)] in the ET o equation. Therefore, the ET o error varies between 65 and 85% of the R n error as air temperature increases from about 20° to 40°C. (author)

Radiation Measurement And Risk Estimation For Pediatric Patients During Routine Diagnostic Examination

International Nuclear Information System (INIS)

Bushra, E.; Sulieman, A.; Osman, H.

2011-01-01

The aim of the present work was to evaluate Entrance Surface Dose (ESD) to the patient using Thermo luminescence dosimeters (TLD) during some common routine pediatrics X-ray examinations in main pediatrics hospitals in Sudan. ESD and Effective Dose (E) for pediatrics have been carried out for 250 patients undergoing five different examinations. The mean ESD ranged for neonates ranged between 0.17 mGy-0.30 mGy per radiograph with scattered thyroid dose 0.01 to 0.19 mGy. The risk of radiation induced cancer of was 0.13 x 10-6.

Estimation of stochastic effects risk in children from areas affected by the Chernobyl accident

International Nuclear Information System (INIS)

Jova S, L.; Garcia L, O.; Valdes R, M.

1996-01-01

Radiation risk estimation of stochastic effect was evaluated in a group of children assisted in the Cuba Republic as part of the program for medical attention with children from areas affected by the Chernobyl accident . Doses, received from different sources, were estimated for risk evaluation. The study shows total detrimental effects between 0,02 - 0,01% for different groups; values lower than expected for developed country (17-20%). Fatal thyroid cancer increased up to 0,07% in one of the studied groups. (authors). 8 refs., 4 tabs

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

Energy Technology Data Exchange (ETDEWEB)

Priharti, W.; Samat, S. B.; Yasir, M. S. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

2015-09-25

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

The Increase in Animal Mortality Risk following Exposure to Sparsely Ionizing Radiation Is Not Linear Quadratic with Dose.

Directory of Open Access Journals (Sweden)

Benjamin M Haley

Full Text Available The US government regulates allowable radiation exposures relying, in large part, on the seventh report from the committee to estimate the Biological Effect of Ionizing Radiation (BEIR VII, which estimated that most contemporary exposures- protracted or low-dose, carry 1.5 fold less risk of carcinogenesis and mortality per Gy than acute exposures of atomic bomb survivors. This correction is known as the dose and dose rate effectiveness factor for the life span study of atomic bomb survivors (DDREFLSS. It was calculated by applying a linear-quadratic dose response model to data from Japanese atomic bomb survivors and a limited number of animal studies.We argue that the linear-quadratic model does not provide appropriate support to estimate the risk of contemporary exposures. In this work, we re-estimated DDREFLSS using 15 animal studies that were not included in BEIR VII's original analysis. Acute exposure data led to a DDREFLSS estimate from 0.9 to 3.0. By contrast, data that included both acute and protracted exposures led to a DDREFLSS estimate from 4.8 to infinity. These two estimates are significantly different, violating the assumptions of the linear-quadratic model, which predicts that DDREFLSS values calculated in either way should be the same.Therefore, we propose that future estimates of the risk of protracted exposures should be based on direct comparisons of data from acute and protracted exposures, rather than from extrapolations from a linear-quadratic model. The risk of low dose exposures may be extrapolated from these protracted estimates, though we encourage ongoing debate as to whether this is the most valid approach. We also encourage efforts to enlarge the datasets used to estimate the risk of protracted exposures by including both human and animal data, carcinogenesis outcomes, a wider range of exposures, and by making more radiobiology data publicly accessible. We believe that these steps will contribute to better estimates

Bioavailable serum estradiol may alter radiation risk of postmenopausal breast cancer: a nested case-control study.

Science.gov (United States)

Grant, Eric J; Cologne, John B; Sharp, Gerald B; Eguchi, Hidetaka; Stevens, Richard G; Izumi, Shizue; Kim, Young-Min; Berrington de González, Amy; Ohishi, Waka; Nakachi, Kei

2018-02-01

Ionizing radiation and high levels of circulating estradiol are known breast cancer carcinogens. We investigated the risk of first primary postmenopausal breast cancer in relation to the combined effects of whole-body ionizing radiation exposure and prediagnostic levels of postmenopausal sex hormones, particularly bioavailable estradiol (bE 2 ). A nested case-control study of 57 incident breast cancer cases matched with 110 controls among atomic bomb survivors. Joint effects of breast radiation dose and circulating levels of sex hormones were assessed using binary regression and path analysis. Radiation exposure, higher levels of bE 2 , testosterone and progesterone, and established reproductive risk factors were positively associated with postmenopausal breast cancer risk. A test for mediation of the effect of radiation via bE 2 level suggested a small (14%) but significant mediation (p = 0.004). The estimated interaction between radiation and bE 2 was large but not significant (interaction = 3.86; p = 0.32). There is accumulating evidence that ionizing radiation not only damages DNA but also alters other organ systems. While caution is needed, some portion of the radiation risk of postmenopausal breast cancer appeared to be mediated through bE 2 levels, which may be evidence for cancer risks due to both direct and indirect effects of radiation.

Updated estimates of the proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionising radiation

International Nuclear Information System (INIS)

Little, Mark P; Wakeford, Richard; Kendall, Gerald M

2009-01-01

The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionising radiation, such as was experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily upon studies of the Japanese A-bomb survivors imply that low-level exposure to ionising radiation, including to ubiquitous natural background radiation, also raises the risk of childhood leukaemia. In a recent paper (Wakeford et al 2009 Leukaemia 23 770-6) we estimated the proportion of childhood leukaemia incidence in Great Britain attributable to natural background radiation to be about 20%. In this paper we employ the two sets of published leukaemia risk models used previously, but use recently published revised estimates of natural background radiation doses received by the red bone marrow of British children to update the previous results. Using the newer dosimetry we calculate that the best estimate of the proportion of cases of childhood leukaemia in Great Britain predicted to be attributable to this source of exposure is 15-20%, although the uncertainty associated with certain stages in the calculation (e.g. the nature of the transfer of risk between populations and the pertinent dose received from naturally occurring alpha-particle-emitting radionuclides) is significant. The slightly lower attributable proportions compared with those previously derived by Wakeford et al (Leukaemia 2009 23 770-6) are largely due to the lower doses (and in particular lower high LET doses) for the first year of life.

Risks associated with low level ionizing radiation (with special reference to nuclear power workers)

International Nuclear Information System (INIS)

1989-01-01

This document describes a project to use epidemiological studies of workers in the nuclear industry to estimate the cancer risk associated with low-dose chronic exposure to ionizing radiation. The project aims both to improve the basis for radiation risk assessment and to test the validity of currently used models for the extrapolation of radiation risk. This report focusses on the former aim, and summarizes discussions at two meetings held in June 1988. One of these was a small working group consisting mainly of epidemiologists who had carried out studies of nuclear workers; the other included nominees of the nuclear industries of eleven countries as well as epidemiologists and radiation physicists and biologists. As a result of the meetings, efforts are underway to pool existing data and a feasibility study is addressing the possibility of an international collaborative study of unstudied groups of nuclear workers

Estimating hourly direct and diffuse solar radiation for the compilation of solar radiation distribution maps

International Nuclear Information System (INIS)

Ueyama, H.

2005-01-01

This paper presents a new method for estimating hourly direct and diffuse solar radiation. The essence of the method is the estimation of two important factors related to solar radiation, atmospheric transmittance and a dimensionless parameter, using empirical and physical equations and data from general meteorological observation stations. An equation for atmospheric transmittance of direct solar radiation and a dimensionless parameter representing diffuse solar radiation are developed. The equation is based on multiple regression analysis and uses three parameters as explanatory variates: calculated hourly extraterrestrial solar radiation on a horizontal plane, observed hourly sunshine duration and hourly precipitation as observed at a local meteorological observatory. The dimensionless parameter for estimating a diffuse solar radiation is then determined by linear least squares using observed hourly solar radiation at a local meteorological observatory. The estimated root mean square error (RMSE) of hourly direct and diffuse solar radiation is about 0.0-0.2 MJ¥m(-2)¥h(-1) in each mean period. The RMSE of the ten-day and monthly means of these quantities is about 0.0-0.2 MJ¥m(-2)¥h(-1), based on comparisons with AMeDAS station data, located at a distance of 6 km

Introduction to dosimetry and risk estimation of second cancer induction following radiotherapy

International Nuclear Information System (INIS)

Harrison, R.M.

2013-01-01

This brief review of dosimetry in second cancer dosimetry introduces work carried out by Working Group 9 (Radiation Protection Dosimetry in Medicine) of the European Radiation Dosimetry Group (EURADOS). The work described in the following papers in this edition was presented at a Workshop on Dosimetry for Second Cancer Risk Estimation given at the EURADOS Annual meeting in Vienna on February 8th 2012. The work concentrates on the measurement of out-of-field doses in water tanks and BOMAB-like phantoms using a variety of dosimeters to measure photon and neutron doses. These include optically stimulated luminescence (OSL), radiophotoluminescence (RPL) and thermoluminescence (TLD) dosimeters for photon dosimetry (together with ion chambers for reference measurements traceable to primary standards) and track etch and bubble detectors for neutron measurements. A discussion of the various phantoms available for these measurements is presented together with a brief introduction to a model for the relationship between organ doses and the risk of induction of second cancers. The estimation of second cancer risks is not trivial and involves processes which are currently incompletely understood. However, progress in this field requires a robust foundation and methodology for the measurement or calculation of organ doses following radiotherapy, so that risks can be placed in perspective, algorithms for out-of-field doses can be compared with measured data, and future epidemiological studies may have a reliable foundation of organ dosimetry for retrospective dosimetry studies. -- Highlights: ► Brief review of second cancer induction following radiotherapy. ► Out-of-field doses for estimating risks to remote organs. ► Introduction to dosimetry techniques and dosimeters used. ► Out-of-field dose measurements in phantoms

On ionising radiation and breast cancer risk

Energy Technology Data Exchange (ETDEWEB)

Mattson, Anders

1999-05-01

A cohort of 3,090 women with clinical diagnosis of benign breast disease (BBD) was studied. Of these, 1,216 were treated with radiation therapy during 1925-54 (median age 40 years). The mean dose to the breasts was 5.8 Gy (range 0-50 Gy). Among other organs the lung received the highest scattered dose (0.75 Gy; range 0.004-8.98 Gy) and the rectum the lowest (0.008 Gy; range 0-0.06 Gy). A pooled analysis of eight breast cancer incidence cohorts was done, including: tumour registry data on breast cancer incidence among women in the Life Span Study cohort of atomic bomb survivors; women in Massachusetts who received repeated chest fluoroscopic during lung collapse treatment for tuberculosis; women who received x-ray therapy for acute post-partum mastitis; women who were irradiated in infancy for enlarged thymus glands ; two Swedish cohorts of women who received radiation treatments during infancy for skin hemangioma; and the BBD cohort. Together the cohorts included almost 78,000 women (-35,000 were exposed), around 1.8 million woman-years and 1500 cases. The breast cancer incidence rate as a function of breast dose was analysed using linear-quadratic Poisson regression models. Cell-killing effects and other modifying effects were incorporated through additional log-linear terms. Additive (EAR) and multiplicative (ERR) models were compared in estimating the age-at-exposure patterns and time related excess. The carcinogenic risks associated with radiation in mammographic mass screening is evaluated. Assessment was made in terms of breast cancer mortality and years of life. Effects were related to rates not influenced by a mammographic mass screening program and based on a hypothetical cohort of 100,000 40-year old women with no history of breast cancer being followed to 100 years of age. Two radiation risk assumptions were compared. The dose-response relationship is linear with little support in data for an upward curvature at low to medium doses. The competing effect

On ionising radiation and breast cancer risk

International Nuclear Information System (INIS)

Mattson, Anders

1999-01-01

A cohort of 3,090 women with clinical diagnosis of benign breast disease (BBD) was studied. Of these, 1,216 were treated with radiation therapy during 1925-54 (median age 40 years). The mean dose to the breasts was 5.8 Gy (range 0-50 Gy). Among other organs the lung received the highest scattered dose (0.75 Gy; range 0.004-8.98 Gy) and the rectum the lowest (0.008 Gy; range 0-0.06 Gy). A pooled analysis of eight breast cancer incidence cohorts was done, including: tumour registry data on breast cancer incidence among women in the Life Span Study cohort of atomic bomb survivors; women in Massachusetts who received repeated chest fluoroscopic during lung collapse treatment for tuberculosis; women who received x-ray therapy for acute post-partum mastitis; women who were irradiated in infancy for enlarged thymus glands ; two Swedish cohorts of women who received radiation treatments during infancy for skin hemangioma; and the BBD) cohort. Together the cohorts included almost 78,000 women (-35,000 were exposed), around 1.8 million woman-years and 1500 cases. The breast cancer incidence rate as a function of breast dose was analysed using linear-quadratic Poisson regression models. Cell-killing effects and other modifying effects were incorporated through additional log-linear terms. Additive (EAR) and multiplicative (ERR) models were compared in estimating the age-at-exposure patterns and time related excess. The carcinogenic risks associated with radiation in mammographic mass screening is evaluated. Assessment was made in terms of breast cancer mortality and years of life. Effects were related to rates not influenced by a mammographic mass screening program and based on a hypothetical cohort of 100,000 40-year old women with no history of breast cancer being followed to 100 years of age. Two radiation risk assumptions were compared. The dose-response relationship is linear with little support in data for an upward curvature at low to medium doses. The competing effect

Risk estimates of stochastic effects due to exposure to radiation - a stochastic harm index

International Nuclear Information System (INIS)

Gonen, Y.G.

1980-01-01

The effects of exposure to low level radiation on the survival probability and life expectancy were investigated. The 1977 vital statistics of Jewish males in Israel were used as a baseline, mainly the data on normalized survival probability and life expectation as functions of age. Assumed effects of exposure were superposed on these data and the net differences calculated. It was found that the realistic rate effects of exposure to radiation are generally less than calculated by multiplying the collective dose by the risk factor. The effects are strongly age-dependent, decreasing sharply with age at exposure. The assumed harm due to exposure can be more than offset by improvements in medical care and safety. (H.K.)

Estimation of diffuse from measured global solar radiation

International Nuclear Information System (INIS)

Moriarty, W.W.

1991-01-01

A data set of quality controlled radiation observations from stations scattered throughout Australia was formed and further screened to remove residual doubtful observations. It was then divided into groups by solar elevation, and used to find average relationships for each elevation group between relative global radiation (clearness index - the measured global radiation expressed as a proportion of the radiation on a horizontal surface at the top of the atmosphere) and relative diffuse radiation. Clear-cut relationships were found, which were then fitted by polynomial expressions giving the relative diffuse radiation as a function of relative global radiation and solar elevation. When these expressions were used to estimate the diffuse radiation from the global, the results had a slightly smaller spread of errors than those from an earlier technique given by Spencer. It was found that the errors were related to cloud amount, and further relationships were developed giving the errors as functions of global radiation, solar elevation, and the fraction of sky obscured by high cloud and by opaque (low and middle level) cloud. When these relationships were used to adjust the first estimates of diffuse radiation, there was a considerable reduction in the number of large errors