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Sample records for biological dose estimation

  1. Dose estimation by biological methods

    International Nuclear Information System (INIS)

    The human being is exposed to strong artificial radiation sources, mainly of two forms: the first is referred to the occupationally exposed personnel (POE) and the second, to the persons that require radiological treatment. A third form less common is by accidents. In all these conditions it is very important to estimate the absorbed dose. The classical biological dosimetry is based in the dicentric analysis. The present work is part of researches to the process to validate the In situ Fluorescent hybridation (FISH) technique which allows to analyse the aberrations on the chromosomes. (Author)

  2. Biological dosimetry - Dose estimation method using biomakers

    International Nuclear Information System (INIS)

    The individual radiation dose estimation is an important step in the radiation risk assessment. In case of radiation incident or radiation accident, sometime, physical dosimetry method can not be used for calculating the individual radiation dose, the other complement method such as biological dosimetry is very necessary. This method is based on the quantitative specific biomarkers induced by ionizing radiation, such as dicentric chromosomes, translocations, micronuclei... in human peripheral blood lymphocytes. The basis of the biological dosimetry method is the close relationship between the biomarkers and absorbed dose or dose rate; the effects of in vitro and in vivo are similar, so it is able to generate the calibration dose-effect curve in vitro for in vivo assessment. Possibilities and perspectives for performing biological dosimetry method in radiation protection area are presented in this report. (author)

  3. Cytogenetic biological dosimetry. Dose estimative in accidental exposure

    International Nuclear Information System (INIS)

    The methodology of cytogenetic biological dosimetry is studied. The application in estimation of dose in five cases of accidental exposure is reported. An hematological study and culture of lymphocytes is presented. (M.A.C.)

  4. Biological dose estimation for accidental supra-high dose gamma-ray exposure

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y., E-mail: yingchen29@yahoo.com.cn [Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Haidian District, Beijing 100850 (China); Yan, X.K. [Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Haidian District, Beijing 100850 (China); Department of Radiation Safety, Beijing Institute of Nuclear and Chemical Safety, 14 Guan-cun, Dongcheng District, Beijing 100077 (China); Du, J.; Wang, Z.D.; Zhang, X.Q.; Zeng, F.G.; Zhou, P.K. [Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Haidian District, Beijing 100850 (China)

    2011-09-15

    To correctly estimate the biological dose of victims accidentally exposed to a very high dose of {sup 60}Co gamma-ray, a new dose-effect curve of chromosomal dicentrics/multicentrics and rings in the supra-high dose range was established. Peripheral blood from two healthy men was irradiated in vitro with doses of {sup 60}Co gamma-rays ranging from 6 to 22 Gy at a dose rate of 2.0 Gy/min. Lymphocytes were concentrated, cultured and harvested at 52 h, 68 h and 72 h. The numbers of dic + r were counted. The dose-effect curves were established and validated using comparisons with doses from the Tokai-mura accident and were then applied to two victims of supra-high dose exposure accident. The results indicated that there were no significant differences in chromosome aberration frequency among the different culture times from 52 h to 72 h. The 6-22 Gy dose-effect curve was fitted to a linear quadratic model Y = -2.269 + 0.776D - 7.868 x l0{sup -3}D{sup 2}. Using this mathematic model, the dose estimates were similar to data from Tokai-mura which were estimated by PCC ring. Whole body average doses of 9.7 Gy and 18.1 Gy for two victims in the Jining accident were satisfactorily given. We established and successfully applied a new dose-effect curve of chromosomal dicentrics plus ring (dic + r) after 6-22 Gy {gamma}-irradiation from a supra-high dose {sup 60}Co gamma-ray accident.

  5. Biological dose estimation and cytogenetic follow-up observation for a patient with subacute radiation sickness

    International Nuclear Information System (INIS)

    Objective: To conduct the biological dose estimation and cytogenetic observation for the patient with subacute radiation sickness in a 192Ir source radiation accident. Methods: Conventional chromosome aberration analysis and micronucleus assay in peripheral blood lymphocytes were performed, and the accumulated dose was estimated by G function according to the frequencies of dicentric and ring on the patient. Results: The estimated doses were close to those values estimated by physical method, in accordance with the appearance expression of clinical symptoms. At 1.5 and 2.5 years after the accident, clear decrease were observed in dicentric chromosomes but not in acentric fragments and micronuclei. Conclusions: The estimation of accumulated dose by G function can reflect the real degree of radiation damage. The decreased rate of chromosome aberration and micronucleus in the patient with subacute radiation sickness might be slower than those with acute radiation sickness. (authors)

  6. Biological radiation dose estimation by chromosomal aberrations analysis in human peripheral blood (dose-effect curve)

    International Nuclear Information System (INIS)

    In order to draw a dose-effect curve, experimentally gamma ray induced chromosomal aberrations in human peripheral lymphocytes from eight healthy people were studied. Samples from 4 males and 4 females were irradiated in tubes with 0.15, 0.25, 0.5, 1, 1.5, 2, 2.5 gray of gamma ray (Co60 at dose rate 0.3 Gy/min). Irradiated and control samples were incubated in 37 centigrade for 48 hours cell cultures. Cell cultures then were stopped and metaphases spread, Giemsa stained to score the induced chromosomal aberrations. Chromosomal aberrations from 67888 metaphases were scored. Curves from the total number of dicentrics, dicentrics + rings and total numbers of breaks in cell for each individual or for all people were drawn. An increase of all chromosomal aberrations types with the elevation of the doses was observed. The yield of chromosome aberrations is related to the dose used. These curves give a quick useful estimation of the accidentally radiation exposure. (author)

  7. Biologically motivated tumor-models used for risk estimates at low doses of radiation

    International Nuclear Information System (INIS)

    Biologically motivated tumour models are necessary for estimating the radiation risk at low doses, as epidemiological studies cannot give significant results for sufficiently small risks as a matter of principle. The tumour models combine knowledge about the mechanisms of tumour development with epidemiological data and results of animal experiments. The are usefuls for testing hypothesis on radiation carcinogenesis. In the framework of EU-projects European partners work on the difficult task of quantifying the relevant biological parameters, and the radiation risk at low doses. Various data sets are described well by assuming an initiating and a promoting action of radiation. As an example a new analysis of radon-induced lung tumours in the Colorado plateau miners is discussed. The estimated lifetime relative risk extrapolated to exposures as they hold in indoor situations is substantially lower than estimated in the BEIR VI report. (orig.)

  8. Application of Benchmark Dose (BMD) in Estimating Biological Exposure Limit (BEL) to Cadmium

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To estimate the biological exposure limit (BEL) using benchmark dose (BMD) based on two sets of data from occupational epidemiology. Methods Cadmium-exposed workers were selected from a cadmium smelting factory and a zinc product factory. Doctors, nurses or shop assistants living in the same area served as a control group. Urinary cadmium (UCd) was used as an exposure biomarker and urinary β2-microgloburin (B2M), N-acetyl-β-D-glucosaminidase (NAG) and albumin (ALB) as effect biomarkers. All urine parameters were adjusted by urinary creatinine. Software of BMDS (Version 1.3.2, EPA.U.S.A) was used to calculate BMD. Results The cut-off point (abnormal values) was determined based on the upper limit of 95% of effect biomarkers in control group. There was a significant dose response relationship between the effect biomarkers (urinary B2M, NAG, and ALB) and exposure biomarker (UCd). BEL value was 5 μg/g creatinine for UB2M as an effect biomarker, consistent with the recommendation of WHO. BEL could be estimated by using the method of BMD. BEL value was 3 μg/g creatinine for UNAG as an effect biomarker. The more sensitive the used biomarker is, the more occupational population will be protected. Conclusion BMD can be used in estimating the biological exposure limit (BEL). UNAG is a sensitive biomarker for estimating BEL after cadmium exposure.

  9. Dose estimation by biological methods; Estimacion de dosis por metodos biologicos

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero C, C.; David C, L.; Serment G, J.; Brena V, M. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The human being is exposed to strong artificial radiation sources, mainly of two forms: the first is referred to the occupationally exposed personnel (POE) and the second, to the persons that require radiological treatment. A third form less common is by accidents. In all these conditions it is very important to estimate the absorbed dose. The classical biological dosimetry is based in the dicentric analysis. The present work is part of researches to the process to validate the In situ Fluorescent hybridation (FISH) technique which allows to analyse the aberrations on the chromosomes. (Author)

  10. Biological dose estimation of partial body exposures in cervix cancer patients

    International Nuclear Information System (INIS)

    At present, unstable chromosome aberrations analysis in peripheral blood lymphocytes is the most sensitive method to provide a biological estimation of the dose in accidental radiation over exposures. The assessment of the dose is particularly reliable in cases of acute, uniform, whole-body exposures or after irradiation of large parts of the body. However, the scenarios of most radiation accidents result in partial-body exposures or non-uniform dose distribution, leading to a differential exposure of lymphocytes in the body. Inhomogeneity produces a yield of dicentrics, which does not conform to a Poisson distribution, but is generally over dispersed. This arises because those lymphocytes in tissues outside the radiation field will not be damaged. Most of the lymphocytes (80 %) belong to the 'redistributional pool' (lymphatic tissues and other organs) and made recirculate into peripheral blood producing a mixed irradiated and unirradiated population of lymphocytes. So-called over dispersion, with a variance greater than the mean, can be taken as an indication of non-uniform exposure. The main factors operating in vivo partial-body irradiation may be the location and size of the irradiation field and, at high doses, various cellular reactions such as reduced blast transformation, mitotic delay or interphase death may contribute. For partial-body exposures, mathematical-statistical analysis of chromosome aberration data can be performed to derive a dose estimate for the irradiated fraction of the body, been more realistic than to quote a mean equivalent uniform whole body dose. The 'Contaminated Poisson' method of Dolphin or the Qdr method of Sasaki, both based on similar principles, can achieve this. Contaminated Poisson considers the over dispersed distribution of dicentrics among all the cells scored. The observed distribution is considered to be the sum of a Poisson distribution, which represents the irradiated fraction of the body, and the remaining unexposed

  11. TLD estimation of absorbed dose for 131I on the surface of biological organs of REMCAL phantom

    International Nuclear Information System (INIS)

    In nuclear medicine, the accuracy of absorbed dose of an internally distributed radiopharmaceuticals estimated by the MIRD (medical internal radiation dose) method depends on the cumulated activity of the source organs and their mass. The usual method for obtaining the cumulated activities are: 1) direct measurements by a) positron emission tomography (PET) and b) single photon emission computed tomography (SPECT) 2) extrapolation from animal data and 3) calculations based on the mathematical biokinetic model. Among these methods, extrapolation of animal data to humans includes inevitable inaccuracy due to large interspecies metabolic differences with regard to the administered radiochemical. Biokinetic modeling requires adequate knowledge of various kinetic parameters, which is based on some biological assumptions. Direct measurements can provide cumulated distributions with fewer biological assumptions. But direct measurements of PET/SPECT are difficult to perform routinely. A method has been developed to obtain the surface dose of different biological organs by using TLDs. Here, a number of TLDs are placed just above the surface of the biological organs of the REMCAL Alderson human phantom filled with water. Firstly, investigation of the accuracy of this method by calibration studies using the said phantom, which is having the entire biological organ intact and simulate the organs as human body is done. These organs are filled with the known activity of the radioisotope. In the present study, estimation of radiation dose received by fifteen different target organs, when the known activity was filled in the three major organs of interest was carried out

  12. Biological dosimetry - a Bayesian approach in the presentation of the uncertainty of the estimated dose in cases of exposure to low dose radiation

    International Nuclear Information System (INIS)

    Biodosimetry laboratory experience has shown that there are limitations in the existing statistical methodology. Statistical difficulties generally occur due to the low number of aberrations leading to large uncertainties for dose estimation. Some problems derived from limitations of the classical statistical methodology, which requires that chromosome aberration yields be considered as something fixed and consequently provides a deterministic dose estimation and associated confidence limits. On the other hand, recipients of biological dosimetry reports, including medical doctors, regulators and the patients themselves may have a limited comprehension of statistics and of informed reports. Thus, the objective of the present paper is to use a Bayesian approach to present the uncertainty on the estimated dose to which a person could be exposed, in the case of low dose (occupational doses) radiation exposure. Such methodology will allow the biodosimetrists to adopt a probabilistic approach for the cytogenetic data analysis. At present, classical statistics allows to produce a confidence interval to report such dose, with a lower limit that could not detach from zero. In this situation it becomes difficult to make decisions as they could impact on the labor activities of the worker if an exposure exceeding the occupational dose limits is inferred. The proposed Bayesian approach is applied to occupational exposure scenario to contribute to take the appropriate radiation protection measures. (authors)

  13. Biologically based pesticide dose estimates for children in an agricultural community.

    OpenAIRE

    Fenske, R A; Kissel, J C; Lu, C.; Kalman, D A; Simcox, N J; Allen, E. H.; Keifer, M.C.

    2000-01-01

    Current pesticide health risk assessments in the United States require the characterization of aggregate exposure and cumulative risk in the setting of food tolerances. Biologic monitoring can aggregate exposures from all sources and routes, and can integrate exposures for chemicals with a common mechanism of action. Its value was demonstrated in a recent study of organophosphorus (OP) pesticide exposure among 109 children in an agricultural community in Washington State; 91 of the children h...

  14. Biological characterization of radiation exposure and dose estimates for inhaled uranium milling effluents. Annual progress report, April 1981-March 1982

    International Nuclear Information System (INIS)

    The problems addressed are the protection of uranium will workers from occupational exposure to uranium through routine bioassay programs and the assessment of accidental worker exposures. Comparisons of chemical properties and the biological behavior of refined uranium ore (yellowcake) are made to identify important properties that influence uranium distribution patterns among organs. These studies will facilitate calculations of organ doses for specific exposures and associated health risk estimates and will identify important bioassay procedures to improve evaluations of human exposures. Sampling of airborne yellowcake at four uranium mills showed that aerosols were heterogeneous, changed with time and contained approx. 50% of the airborne uranium in particles greater than 12 μm aerodynamic diameter. Results are related to specific packaging steps and to predictions of appreciable upper respiratory tract deposition rates for the aerosols, if inhaled by a worker without respiratory protection. Previously used in vitro dissolution techniques were evaluated and the uses of the results for interpreting urinary bioassay data are described. Preliminary results from an inhalation experiment using rats indicate that the clearance patterns of inhaled uranium from lung agreed quantitatively with results from in vitro dissolution and infrared analyses of the yellowcake used. Preliminary results from an experiment to simulate contamination of a wound by yellowcake showed that more of the implanted dose of a less soluble form of yellowcake was retained at the wound site than of a more soluble form at 32 days after implantation. The results did not quantitatively agree with in vitro dissolution results. A two-year study of yellowcake from two mills was initiated. Twenty Beagle dogs were exposed by nose-only inhalation to a more soluble form of yellowcake and 20 to a less soluble form

  15. The MIRD method of estimating absorbed dose

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine.

  16. Radiation biology of low doses

    International Nuclear Information System (INIS)

    Present risk assessments and standards in radiation protection are based on the so-called linear no-threshold (LNT) dose - effect hypothesis, i.e., on a linear, proportional relationship between radiation doses and their effects on biological systems. This concept presupposes that any dose, irrespective of its level and time of occurrence, carries the same risk coefficient and, moreover, that no individual biological effects are taken into account. This contribution presents studies of low energy transfer (LET) radiation which deal with the risk of cancer to individual cells. According to the LNT hypothesis, the relationship for the occurrence of these potential effects should be constant over the dose range: successful repair, cell death, mutation with potential carcinogenesis. The results of the studies presented here indicate more differentiated effects as a function of dose application as far as damage to cellular DNA by ionizing radiation is concerned. At the same overall dose level, multiple exposures to low doses sometimes give rise to much smaller effects than those arising from one single exposure to the total dose. These adaptive effects of cells are known from other studies. The results of the study allow the conclusion to be drawn that non-linear relationships must be assumed to exist for the LET radiation considered. Correspondingly, the linear no-threshold hypothesis model should at least be reconsidered with respect to the low dose range in the light of recent biological findings. The inclusion of other topical research findings also could give rise to a new, revised, risk-oriented approach in radiological protection. (orig.)

  17. Radiation dose estimates for radiopharmaceuticals

    International Nuclear Information System (INIS)

    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

  18. Weldon Spring historical dose estimate

    Energy Technology Data Exchange (ETDEWEB)

    Meshkov, N.; Benioff, P.; Wang, J.; Yuan, Y.

    1986-07-01

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr.

  19. Weldon Spring historical dose estimate

    International Nuclear Information System (INIS)

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr

  20. Dose estimation in interventional radiology

    International Nuclear Information System (INIS)

    Values of absorbed dose received for patients and professionals in interventionist radiology can be significant, therefore these procedures to spend of long times of fluoroscopy. There are diverse methods of estimate and reduce values dose in interventional radiology particularly because the fluoroscopy is responsible for the high contribution of dose in the patient and the professionals. The aim of the present work is using of thermoluminescent dosimetry in order to determine dose values in extremities (fingers) of professionals involved in interventional radiology and the dose-area (DAP) was also investigated, using a Diamentor. This evaluation of DAP is important because in this procedures there are interest in multiple regions of the organism. The estimated dose values for radiology professionals in the present study were: 137,25 mSv/years for doctors, 40,27 mSv/years for nurses and 51,95 mSv/years for the auxiliary doctor. These values are lower than the norm, but this study did not take into consideration for emergency examinations, because they are specific procedures. The DAP values obtained are elevated, for patients when they are associated with a cancer risk, but they are inside the same range of values as those encountered in the literature. (author)

  1. Biology responses to low dose radiation

    International Nuclear Information System (INIS)

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

  2. Generalized Spearman estimators of relative dose.

    Science.gov (United States)

    Morton, R

    1981-06-01

    In a biological assay the expected response may be transformed to a variable bounded between 0 and 1. If the transformed response is regarded as analogous to the tolerance distribution function, the mean of that distribution may be estimated for the standard and test preparations, and a simple estimator of the relative potency obtained. The special case where the identity transformation is used for a quantal response corresponds to Spearman's estimator, and our generalization has similar unbiasedness properties to that estimator. Asymptotic results are derived when the intervals between dose levels decrease and the sample of each dose level simultaneously increases. These results are evaluated for the case with equal sample sizes at regularly spaced values of the dose metameter. An approximate test for similarity is proposed. If the tolerance distribution is known up to a scale parameter, then the transformation may be chosen so that the estimator is asymptotically fully efficient. An application to the thermal disinfestation of wheat is given. PMID:7272411

  3. New risk estimates at low doses

    International Nuclear Information System (INIS)

    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

  4. Theory and data for estimating the risk at low doses and dose rates

    International Nuclear Information System (INIS)

    Radiological protection bases the Linear Non-Threshold (LNT) model for estimating the risk at low doses and dose rates. Incorporation of risk concept into radiological protection brought the LNT model that implies that there is no wholly ''safe'' dose of radiation. Epidemiological studies have provided statistically reasonable basis for the LNT model for radiological protection. In estimating the cancer risk at low dose and dose rate using the atomic bomb survivor data, the dose and dose rate effectiveness factor (DDREF) is estimated. Theoretical and methodological issues on the DDREF emerged from the biological points of view. The International Commission of Radiological Protection (ICRP) indicated that uncertainty analysis of the risk suggests that the LNT model is more reasonable than the threshold model with uncertain threshold doses. The latest epidemiological studies at low dose rates support LNT models. The gap between biology and epidemiology is increasing although some issues already exist in risk estimation at low doses. To get more scientifically reliable risk estimate, the dialogue between biology and epidemiology is needed to construct the framework of risk estimation such as biologically-based carcinogenesis models. (author)

  5. Biological characterization of radiation exposure and dose estimates for inhaled uranium milling effluents. Annual progress report April 1, 1982-March 31, 1983

    Energy Technology Data Exchange (ETDEWEB)

    Eidson, A.F.

    1984-05-01

    The problems addressed are the protection of uranium mill workers from occupational exposure to uranium through routine bioassay programs and the assessment of accidental worker exposures. Comparisons of chemical properties and the biological behavior of refined uranium ore (yellowcake) are made to identify important properties that influence uranium distribution patterns among organs. These studies will facilitate calculations of organ doses for specific exposures and associated health risk estimates and will identify important bioassay procedures to improve evaluations of human exposures. A quantitative analytical method for yellowcake was developed based on the infrared absorption of ammonium diuranate and U/sub 3/O/sub 8/ mixtures in KBr. The method was applied to yellowcake samples obtained from six operating mills. The composition of yellowcake from the six mills ranged from nearly pure ammonium diuranate to nearly pure U/sub 3/O/sub 8/. The composition of yellowcake samples taken from lots from the same mill was only somewhat less variable. Because uranium mill workers might be exposed to yellowcake either by contamination of a wound or by inhalation, a study of retention and translocation of uranium after subcutaneous implantation in rats was done. The results showed that 49% of the implanted yellowcake cleared from the body with a half-time (T sub 1/2) in the body of 0.3 days, and the remainder was cleared with a T sub 1/2 of 11 to 30 days. Exposures of Beagle dogs by nose-only inhalation to aerosols of commercial yellowcake were completed. Biochemical indicators of kidney dysfunction that appeared in blood and urine 4 to 8 days after exposure to the more soluble yellowcake showed significant changes in dogs, but levels returned to normal by 16 days after exposure. No biochemical evidence of kidney dysfunction was observed in dogs exposed to the less soluble yellowcake form. 18 figures, 9 tables.

  6. Biological characterization of radiation exposure and dose estimates for inhaled uranium milling effluents. Annual progress report April 1, 1982-March 31, 1983

    International Nuclear Information System (INIS)

    The problems addressed are the protection of uranium mill workers from occupational exposure to uranium through routine bioassay programs and the assessment of accidental worker exposures. Comparisons of chemical properties and the biological behavior of refined uranium ore (yellowcake) are made to identify important properties that influence uranium distribution patterns among organs. These studies will facilitate calculations of organ doses for specific exposures and associated health risk estimates and will identify important bioassay procedures to improve evaluations of human exposures. A quantitative analytical method for yellowcake was developed based on the infrared absorption of ammonium diuranate and U3O8 mixtures in KBr. The method was applied to yellowcake samples obtained from six operating mills. The composition of yellowcake from the six mills ranged from nearly pure ammonium diuranate to nearly pure U3O8. The composition of yellowcake samples taken from lots from the same mill was only somewhat less variable. Because uranium mill workers might be exposed to yellowcake either by contamination of a wound or by inhalation, a study of retention and translocation of uranium after subcutaneous implantation in rats was done. The results showed that 49% of the implanted yellowcake cleared from the body with a half-time (T sub 1/2) in the body of 0.3 days, and the remainder was cleared with a T sub 1/2 of 11 to 30 days. Exposures of Beagle dogs by nose-only inhalation to aerosols of commercial yellowcake were completed. Biochemical indicators of kidney dysfunction that appeared in blood and urine 4 to 8 days after exposure to the more soluble yellowcake showed significant changes in dogs, but levels returned to normal by 16 days after exposure. No biochemical evidence of kidney dysfunction was observed in dogs exposed to the less soluble yellowcake form. 18 figures, 9 tables

  7. Observations on the biological foundations of dose limits

    International Nuclear Information System (INIS)

    In the present article the author examines a certain number of results of biological observations associated to external irradiations and arrives at following conclusions: For γ-radiation the results show an biological efficiency which is below the value of 10-4 rad-1 and which is equally sensitive to lower rates than the minimal dose. For X-radiation at the maximal dose rate of 30 rad/min the observed dose-effect relations are linear according to the CIPR model. For neutrons recently a revision of the estimations of the expositions of the survivants of the nuclear explosions at Japan was performed. The first published results of this revision lead to a dose-effect relationship of D0.7 and a biological efficiency of low doses which is more important than the results of precedent estimations. (orig.)

  8. Biological indicators for radiation absorbed dose: a review

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-06-01

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

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

    International Nuclear Information System (INIS)

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

  11. Uncertainty analysis of dose estimation

    International Nuclear Information System (INIS)

    This article is designed from the point of quantification of uncertainty associated with the measurement of radiation dose. Therefore, before introducing uncertainty quantification, it is always better to recap the few common terminologies of radiation dosimetry. We know that when radiation interacts with matter, electrons are removed from atoms through the process called ionization. When the energy of the radiation is not strong enough, electron excitation (jumps from lower shells to upper shells) may occur. The excitation of molecules or breaking of molecular bonds can also occur, causing damage to living cells. When the energy of radiation is large enough to produce ionizations, the radiation is called ionizing radiation. Otherwise, it is called non-ionizing radiation. When dealing with the interaction of gamma and X-rays in air, the term exposure is used. Exposure measures the electric charge (positive or negative) produced by electromagnetic radiation in a unit mass of air, at normal atmospheric conditions

  12. Gamma dose estimation with the thermoluminescence method

    Energy Technology Data Exchange (ETDEWEB)

    Kumamoto, Yoshikazu [National Inst. of Radiological Sciences, Chiba (Japan)

    1994-03-01

    Absorbed dose in radiation accidents can be estimated with the aid of materials which have the ability of dose recording and were exposed during the accidents. Quartz in bricks and tiles used to construct the buildings has the thermoluminescent properties. These materials exposed to radiations emit light when heated. Quartz and ruby have been used for the estimation of dose. The requirements for such dosemeters include; (1)the high kiln temperature at which all thermoluminescent energies accrued from natural radiations are erased. (2)the negligible fading of thermoluminescent energies after the exposure to radiations. (3)the determination of dose from natural radiations after the making of the matcrials. (4)the geometry of the place at which materials are collected. Bricks or tiles are crushed in the motar, sieved into sizes, washed with HF, HCl, alchol, aceton and water, and given with a known calibration dose. The pre-dose method and high-temperature method are used. In the former, glow curves with and without calibration dose are recorded. In the latter, glow peaks at 110degC with and without calibration dose are recorded after the heating of quartz up to 500degC. In this report, the method of the sample preparation, the measurement procedures and the results of dose estimation in the atomic bombing, iridium-192 and Chernobyl accident are described. (author).

  13. Low dose irradiation and biological defense mechanisms

    International Nuclear Information System (INIS)

    It has been generally accepted in the context of radiation protection that ionizing radiation has some adverse effect even at low doses. However, epidemiological studies of human populations cannot definitively show its existence or absence. Furthermore, recent studies of populations living in areas of different background radiation levels reported some decrease in adverse health effects at high background levels. Genetic studies of atomic bomb survivors failed to produce statistically significant findings on the mutagenic effects of ionizing radiation. A British study however, suggests that a father's exposure to low dose radiation on the job may increase his children's risk of leukemia. On the other hand, many experimental studies have raised the possibility that low doses of ionizing radiation may not be harmful or may even produce stimulating or adaptive responses. The term 'hormesis' has come to be used to describe these phenomena produced by low doses of ionizing radiation when they were beneficial for the organisms studied. At the end of the International Conference on Low Dose Irradiation one conclusion appeared to be justified: radiation produces an adaptive response, though it is not universally detected yet. The conference failed to obtain any consensus on risk assessment at low doses, but raised many problems to be dealt with by future studies. The editors therefore believe that the Proceedings will be useful for all scientists and people concerned with radiation protection and the biological effects of low-dose irradiation

  14. Estimation of dose from chromosome aberration rate

    International Nuclear Information System (INIS)

    The methods and skills of evaluating dose from correctly scored shromsome aberration rate are presented, and supplemented with corresponding BASIC computer code. The possibility and preventive measures of excessive probability of missing score of the aberrations in some of the current routine score methods are discussed. The use of dose-effect relationship with exposure time correction factor G in evaluating doses and their confidence intervals, dose estimation in mixed n-γ exposure, and identification of high by nonuniform acute exposure to low LET radiation and its dose estimation are discussed in more detail. The difference of estimated dose due to whether the interaction between subleisoms produced by n and γ have been taken into account is examined. In fitting the standard dose-aberration rate curve, proper weighing of experiment points and comparison with commonly accepted values are emphasised, and the coefficient of variation σy√y of the aberration rate y as a function of dose and exposure time is given. In appendix I and II, the dose-aberration rate formula is derived from dual action theory, and the time variation of subleisom is illustrated and in appendix III, the estimation of dose from scores of two different types of aberrations (of other related score) is illustrated. Two computer codes are given in appendix IV, one is a simple code, the other a complete code, including the fitting of standard curve. the skills of using compressed data storage, and the production of simulated 'data ' for testing the curve fitting procedure are also given

  15. Biological indicators for radiation dose assessment

    International Nuclear Information System (INIS)

    After an introductory report on the present level of practical experience in using biological indicator systems to identify and assess doses from radiation exposures, the state of the art in the field of biochemical, cytological and immunological indicators was presented as a basis for discussions in working groups. With reference to the type of radiation - gamma radiation, electrons, neutrons - the question was examined how and to which extent body doses could be evaluated on the basis of results from biological indicator systems. The indicator systems were examined and evaluated in working groups under the aspects of practical use, validity of results and demand of research according to uniform criteria. These were, among others, dose effect relationship, detection limit, reproducibility and specificity, interference factors, stress and reasonable inconvenience of the examined person, earliest possible availability of results and the maximum time needed to identify a biological effect after radiation exposure, as well as the possible maximum number of persons examined from a population group of radiation exposed individuals. The results of the working groups discussions were compiled and summarized in recommendations. (orig./MG)

  16. Organ dose estimates for the Japanese atomic-bomb survivors

    International Nuclear Information System (INIS)

    Recent studies concerning radiation risks to man by the Committee on Biological Effects of Ionizing Radiation of the National Academy of Sciences-National Research Council and the United Nations Scientific Committee on the Effects of Atomic Radiation have emphasized the need for estimates of dose to organs of the Japanese atomic-bomb survivors. Shielding of internal organs by the body has been investigated for fission-weapon gamma rays and neutrons, and ratios of mean absorbed dose in a number of organs to survivors' T65D assignments of tissue kerma in air are provided for adults. Ratios of mean absorbed dose to tissue kerma in air are provided also for the thyroid and active bone marrow of juveniles. These organ dose estimates for juveniles are of interest in studies of radiation risks due to an elevated incidence of leukemia and thyroid cancer in survivors exposed as children compared to survivors exposed as adults

  17. Effective biological dose from occupational exposure during nanoparticle synthesis

    International Nuclear Information System (INIS)

    Nanomaterial and nanotechnology safety require the characterization of occupational exposure levels for completing a risk assessment. However, equally important is the estimation of the effective internal dose via lung deposition, transport and clearance mechanisms. An integrated source-to-biological dose assessment study is presented using real monitoring data collected during nanoparticle synthesis. Experimental monitoring data of airborne exposure levels during nanoparticle synthesis of CaSO4 and BiPO4 nanoparticles in a research laboratory is coupled with a human lung transport and deposition model, which solves in an Eulerian framework the general dynamic equation for polydisperse aerosols using particle specific physical-chemical properties. Subsequently, the lung deposition model is coupled with a mathematical particle clearance model providing the effective biological dose as well as the time course of the biological dose build-up after exposure. The results for the example of BiPO4 demonstrate that even short exposures throughout the day can lead to particle doses of 1.10·E+08/(kg-bw·8h-shift), with the majority accumulating in the pulmonary region. Clearance of particles is slow and is not completed within a working shift following a 1 hour exposure. It mostly occurs via macrophage activity in the alveolar region, with small amounts transported to the interstitium and less to the lymph nodes.

  18. Effective biological dose from occupational exposure during nanoparticle synthesis

    Science.gov (United States)

    Demou, Evangelia; Tran, Lang; Housiadas, Christos

    2009-02-01

    Nanomaterial and nanotechnology safety require the characterization of occupational exposure levels for completing a risk assessment. However, equally important is the estimation of the effective internal dose via lung deposition, transport and clearance mechanisms. An integrated source-to-biological dose assessment study is presented using real monitoring data collected during nanoparticle synthesis. Experimental monitoring data of airborne exposure levels during nanoparticle synthesis of CaSO4 and BiPO4 nanoparticles in a research laboratory is coupled with a human lung transport and deposition model, which solves in an Eulerian framework the general dynamic equation for polydisperse aerosols using particle specific physical-chemical properties. Subsequently, the lung deposition model is coupled with a mathematical particle clearance model providing the effective biological dose as well as the time course of the biological dose build-up after exposure. The results for the example of BiPO4 demonstrate that even short exposures throughout the day can lead to particle doses of 1.10·E+08#/(kg-bw·8h-shift), with the majority accumulating in the pulmonary region. Clearance of particles is slow and is not completed within a working shift following a 1 hour exposure. It mostly occurs via macrophage activity in the alveolar region, with small amounts transported to the interstitium and less to the lymph nodes.

  19. Three dimensional biological dose distribution of antiprotons

    International Nuclear Information System (INIS)

    The goal of external beam cancer therapy is to destroy the tumour while sparing the healthy tissue around it. In hadron therapy, the dose profile of heavy charged particles satisfies this request, because most of the energy is deposited at the end of the particle path, in the Bragg peak. Antiprotons are even more promising, thanks to the extra energy released by annihilation when captured in a normal atom at the end of range. The aim of the AD-4/ACE experiment at CERN is to determine the increase in biological dose near the Bragg peak due to densely ionizing particles emanating from the annihilation of antiprotons. Initial experiments showed the damage to cells inflicted at the end of the beam for identical damage at the skin level to be four times higher for antiprotons than for protons. The radiation field in a spread-out Bragg peak produced with antiprotons is highly mixed and for proper dose planning knowledge of linear energy transfer (LET) and relative biological efficiency (RBE) at any point in the target is needed. We are studying a number of detection methods for their response to mixed radiation fields with the goal to obtain a direct measurement of the 3D LET distribution and report on first results.

  20. Methemoglobin-Based Biological Dose Assessment for Human Blood.

    Science.gov (United States)

    Zhang, Xiao-Hong; Hu, Xiao-Dan; Zhao, Su-Ying; Xie, Li-Hua; Miao, Yu-Ji; Li, Qun; Min, Rui; Liu, Pei-Dang; Zhang, Hai-Qian

    2016-07-01

    Methemoglobin is an oxidative form of hemoglobin in erythrocytes. The authors' aim was to develop a new biological dosimeter based on a methemoglobin assay. Methemoglobin in peripheral blood (of females or males) that was exposed to a Co source (0.20 Gy min) was quantified using an enzyme-linked immunosorbent assay. The dose range was 0.5-8.0 Gy. In a time-course experiment, the time points 0, 0.02, 1, 2, 3, 7, 15, 21, and 30 d after 4-Gy irradiation of heparinized peripheral blood were used. Methemoglobin levels in a lysed erythrocyte pellet from the irradiated blood of females and males increased with the increasing dose. Methemoglobin levels in female blood irradiated with γ-doses more than 4 Gy were significantly higher than those in male samples at the same doses. Two dose-response relations were fitted to the straight line: one is with the correlation coefficient of 0.98 for females, and the other is with the correlation coefficient of 0.99 for males. The lower limit of dose assessment based on methemoglobin is about 1 Gy. Methemoglobin levels in blood as a result of auto-oxidation increase after 7-d storage at -20 °C. The upregulation of methemoglobin induced by γ-radiation persists for ∼3 d. The absorbed doses that were estimated using the two dose-response relations were close to the actual doses. The results suggest that methemoglobin can be used as a rapid and accurate biological dosimeter for early assessment of absorbed γ-dose in human blood. PMID:27218292

  1. A Paradigm Shift in Low Dose Radiation Biology

    Directory of Open Access Journals (Sweden)

    Z. Alatas

    2015-08-01

    Full Text Available When ionizing radiation traverses biological material, some energy depositions occur and ionize directly deoxyribonucleic acid (DNA molecules, the critical target. A classical paradigm in radiobiology is that the deposition of energy in the cell nucleus and the resulting damage to DNA are responsible for the detrimental biological effects of radiation. It is presumed that no radiation effect would be expected in cells that receive no direct radiation exposure through nucleus. The risks of exposure to low dose ionizing radiation are estimated by extrapolating from data obtained after exposure to high dose radiation. However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose radiation than they do to high dose radiation. Moreover, recent experimental evidences from many laboratories reveal the fact that radiation effects also occur in cells that were not exposed to radiation and in the progeny of irradiated cells at delayed times after radiation exposure where cells do not encounter direct DNA damage. Recently, the classical paradigm in radiobiology has been shifted from the nucleus, specifically the DNA, as the principal target for the biological effects of radiation to cells. The universality of target theory has been challenged by phenomena of radiation-induced genomic instability, bystander effect and adaptive response. The new radiation biology paradigm would cover both targeted and non-targeted effects of ionizing radiation. The mechanisms underlying these responses involve biochemical/molecular signals that respond to targeted and non-targeted events. These results brought in understanding that the biological response to low dose radiation at tissue or organism level is a complex process of integrated response of cellular targets as well as extra-cellular factors. Biological understanding of

  2. Biological effect of low dose radiation

    International Nuclear Information System (INIS)

    This document describes the recent findings in studies of low dose radiation effect with those by authors' group. The low dose radiation must be considered in assessment of radiation effects because it induces the biological influence unexpected hitherto; i.e., the bystander effect and genetic instability. The former is a non-targeted effect that non-irradiated cells undergo the influence of directly irradiated cells nearby, which involves cell death, chromosome aberration, micronucleus formation, mutation and carcinogenesis through cellular gap junction and/or by signal factors released. Authors' group has found the radical(s) possessing as long life time as >20 hr released from the targeted cells, a possible mediator of the effect; the generation of aneuploid cells as an early carcinogenetic change; and at dose level <10 Gy, activation of MAPK signal pathway leading to relaxation of chromatin structure. The genetic instability means the loss of stability where replication and conservation of genome are normally maintained, and is also a cause of the late radiation effect. The group has revealed that active oxygen molecules can affect the late effect like delayed cell death, giant cell formation and chromosome aberration, all of which lead to the instability, and is investigating the hypothesis that the telomere instability resulted from the abnormal post-exposure interaction with its nuclear membrane or between chromatin and nuclear matrix, is enhanced by structural distortion of nuclear genes. As well, shown is the possible suppression of carcinogenesis by p53. The group, to elucidate the mechanism underlying the low dose radiation effect, is conducting their studies in consideration of the sequential bases of physical, chemical and biological processes. (R.T.)

  3. Estimation of Absorbed Dose in Occlusal Radiography

    International Nuclear Information System (INIS)

    The purpose of this study was to estimate absorbed dose of each important anatomic site of phantom (RT-210 Head and Neck Section R, Humanoid Systems Co., U.S.A.) head in occlusal radiography. X-radiation dosimetry at 12 anatomic sites in maxillary anterior topography, maxillary posterior topography, mandibular anterior cross-section, mandibular posterior cross-section, mandibular anterior topographic, mandibular posterior topographic occlusal projection was performed with calcium sulfate thermoluminescent dosimeters under 70 Kvp and 15 mA, 1/4 second (8 inch cone ) and 1 second (16 inch cone) exposure time. The results obtained were as follows: Skin surface produced highest absorbed dose ranged between 3264 mrad and 4073 mrad but there was little difference between projections. In maxillary anterior topographic occlusal radiography, eyeballs, maxillary sinuses, and pituitary gland sites produced higher absorbed doses than those of other sites. In maxillary posterior topographic occlusal radiography, exposed eyeball site and exposed maxillary sinus site produced high absorbed doses. In mandibular anterior cross-sectional occlusal radiography, all sites were produced relatively low absorbed dose except eyeball sites. In Mandibular posterior cross-sectional occlusal radiography, exposed eyeball site and exposed maxillary sinus site were produced relatively higher absorbed doses than other sites. In mandibular anterior topographic occlusal radiography, maxillary sinuses, submandibular glands, and thyroid gland sites produced high absorbed doses than other sites. In mandibular posterior topographic occlusal radiography, submandibular gland site of the exposed side produced high absorbed dose than other sites and eyeball site of the opposite side produced relatively high absorbed dose.

  4. Estimation of Absorbed Dose in Occlusal Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Young Ah; Choi, Karp Shick [Dept. of Oral Radiology, College of Dentistry, Kyungpuk National University, Daegu (Korea, Republic of); Lee, Sang Han [Dept. of Oral and Maxillofacial Surgery, College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of)

    1990-02-15

    The purpose of this study was to estimate absorbed dose of each important anatomic site of phantom (RT-210 Head and Neck Section R, Humanoid Systems Co., U.S.A.) head in occlusal radiography. X-radiation dosimetry at 12 anatomic sites in maxillary anterior topography, maxillary posterior topography, mandibular anterior cross-section, mandibular posterior cross-section, mandibular anterior topographic, mandibular posterior topographic occlusal projection was performed with calcium sulfate thermoluminescent dosimeters under 70 Kvp and 15 mA, 1/4 second (8 inch cone) and 1 second (16 inch cone) exposure time. The results obtained were as follows: Skin surface produced highest absorbed dose ranged between 3264 mrad and 4073 mrad but there was little difference between projections. In maxillary anterior topographic occlusal radiography, eyeballs, maxillary sinuses, and pituitary gland sites produced higher absorbed doses than those of other sites. In maxillary posterior topographic occlusal radiography, exposed eyeball site and exposed maxillary sinus site produced high absorbed doses. In mandibular anterior cross-sectional occlusal radiography, all sites were produced relatively low absorbed dose except eyeball sites. In Mandibular posterior cross-sectional occlusal radiography, exposed eyeball site and exposed maxillary sinus site were produced relatively higher absorbed doses than other sites. In mandibular anterior topographic occlusal radiography, maxillary sinuses, submandibular glands, and thyroid gland sites produced high absorbed doses than other sites. In mandibular posterior topographic occlusal radiography, submandibular gland site of the exposed side produced high absorbed dose than other sites and eyeball site of the opposite side produced relatively high absorbed dose.

  5. Transmission dose estimation algorithm for tissue deficit

    International Nuclear Information System (INIS)

    Measurement of transmission dose is useful for in vivo dosimetry. In this study, previous algorithm for estimation of transmission dose was modified for use in cases with tissue deficit. The beam data was measured with flat solid phantom in various conditions of tissue deficit. New algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. The algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients using multiple sheets of solid phantoms. The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within ± 1.0% in most situations and within ± 3.0% in experimental settings with irregular contours mimicking breast cancer treatment set-up. Developed algorithm could accurately reflect the effect of tissue deficit and irregularly shaped body contour on transmission dosimetry

  6. Estimation of 18FDG doses's cost

    International Nuclear Information System (INIS)

    The cyclotron facility, essentially for medical use, is far from being a simple establishment of a dedicated device to accelerate particles producing a beta plus emitter radioelement. The cyclotron site encompasses more over all necessary equipments for the production and the quality control of considered radiotracer that 18FDG is just one example. This facility is subject to strict standards in terms of radiopharmaceutical production, radiation level, pressure level and airflow resulting in the production of a drug submitted to the MA (Marketing Authorization). These multiple factors directly influence the final cost of the dose that remains to be reachable by the patient. The aim of this work is to estimate the cost of a dose of 18FDG to ensure financial viability of the project while accessible to the patient. The cost of the facility will entail the following: buildings and utilities, equipment and operational cost. This calculation is possible only if we define in advance the type of cyclotron, which is bound to the market needs in particular the number of PET facilities, the number of scans per day and the radioactive decay of radioelement. Our study represents a simulation that considers some hypothesis. We assumed that the cyclotron is installed in Sousse and that the PET facilities number (positon emission tomography) is 6 in which 4 are located 2 hours away. For a PET scan, the average dose per patient is about 350 MBq (5 MBq/kg) and the exam duration is about 45 minutes. Each center performs 10 tests per day. In terms of fees, we considered device and building's cost, facility amortization, consumables (target, marking accessories), maintenance, remuneration expense and the annual electricity consumption. All our calculations have been reported to the number of working days per year. The estimates were made outside the customs duties and technical assistance that may last up to 2 years. Requirements and needs were estimated at 5.4 curies per day. For

  7. Estimation of effective dose during hysterosalpingography procedures

    International Nuclear Information System (INIS)

    Hysterosalpingography (HSG) is the most frequently used diagnostic tool to evaluate the endometrial cavity and fallopian tube by using conventional x-ray or fluoroscopy. Determination of the patient radiation doses values from x-ray examinations provides useful guidance on where best to concentrate efforts on patient dose reduction in order to optimize the protection of the patients. The aims of this study were to measure the patients entrance surface air kerma doses (ESA K), effective doses and to compare practices between different hospitals in Sudan. ESA K were measured for patient using calibrated thermo luminance dosimeters (TLDs, Gr-200A). Effective doses were estimated using National Radiological Protection Board (NRPB) software. This study was conducted in five radiological departments: Two Teaching Hospitals (A and D), two private hospitals (B and C) and one University Hospital (E). The mean ESD was 20.1 mGy, 28.9 mGy, 13.6 mGy, 58.65 mGy, 35.7, 22.4 and 19.6 mGy for hospitals A,B,C,D, and E), respectively. The mean effective dose was 2.4 mSv, 3.5 mSv, 1.6 mSv, 7.1 mSv and 4.3 mSv in the same order. The study showed wide variations in the ESDs with three of the hospitals having values above the internationally reported values. Number of x-ray images, fluoroscopy time, operator skills x-ray machine type and clinical complexity of the procedures were shown to be major contributors to the variations reported. Results demonstrated the need for standardization of technique throughout the hospital. The results also suggest that there is a need to optimize the procedures. Local DRLs were proposed for the entire procedures. (author)

  8. Estimation of human dose to radon progeny

    Energy Technology Data Exchange (ETDEWEB)

    Shimo, Michikuni [Gifu Coll. of Medical Technology, Sekiichi, Gifu (Japan)

    1996-12-01

    The aim of the paper is the estimation of the effective dose due to radon progeny for Japanese population. The estimation was performed by a modified UNSCEAR equation. The equation was needed the radon concentration annual occupancy time and the tidal volume on Japanese people and the dose conversion coefficient are needed. Furthermore, not only these figures but also unattached fraction and aerosol distribution data obtained in Japan and the factor related to the Japanese living style were used in the calculation. We used following figures as representative value in Japan; radon concentration: 13(6 - 25) Bq/m{sup 3} indoors and 6.7(3.5 - 13) Bq/m{sup 3} outdoors; the equilibrium factor: 0.45(0.35 - 0.57) indoors and 0.70(0.50 - 0.90) outdoors; the occupancy factor: 0.87 indoors, 0.09 outdoors and 0.04 in vehicle for male and 0.91 indoors, 0.06 outdoors and 0.03 in vehicle for female; the tidal volume: 7,000 (4,000 - 8,000) m{sup 3} for male, 6,200 (3,500 - 7,500) m{sup 3} for female. The effective doses due to radon progeny were estimated to be 0.45 mSv/y for male and 0.40 mSv/y for female, and the variance was -80 - +130%. These values were 1/2 - 1/3 as small as values shown by UNSCEAR 1993 Report and estimated by ICRP Publication 65. (author)

  9. Abundance estimation and Conservation Biology

    Directory of Open Access Journals (Sweden)

    Nichols, J. D.

    2004-06-01

    Full Text Available Abundance is the state variable of interest in most population–level ecological research and in most programs involving management and conservation of animal populations. Abundance is the single parameter of interest in capture–recapture models for closed populations (e.g., Darroch, 1958; Otis et al., 1978; Chao, 2001. The initial capture–recapture models developed for partially (Darroch, 1959 and completely (Jolly, 1965; Seber, 1965 open populations represented efforts to relax the restrictive assumption of population closure for the purpose of estimating abundance. Subsequent emphases in capture–recapture work were on survival rate estimation in the 1970’s and 1980’s (e.g., Burnham et al., 1987; Lebreton et al.,1992, and on movement estimation in the 1990’s (Brownie et al., 1993; Schwarz et al., 1993. However, from the mid–1990’s until the present time, capture–recapture investigators have expressed a renewed interest in abundance and related parameters (Pradel, 1996; Schwarz & Arnason, 1996; Schwarz, 2001. The focus of this session was abundance, and presentations covered topics ranging from estimation of abundance and rate of change in abundance, to inferences about the demographic processes underlying changes in abundance, to occupancy as a surrogate of abundance. The plenary paper by Link & Barker (2004 is provocative and very interesting, and it contains a number of important messages and suggestions. Link & Barker (2004 emphasize that the increasing complexity of capture–recapture models has resulted in large numbers of parameters and that a challenge to ecologists is to extract ecological signals from this complexity. They offer hierarchical models as a natural approach to inference in which traditional parameters are viewed as realizations of stochastic processes. These processes are governed by hyperparameters, and the inferential approach focuses on these hyperparameters. Link & Barker (2004 also suggest that

  10. Improved dose estimates for nuclear criticality accidents

    International Nuclear Information System (INIS)

    Slide rules are improved for estimating doses and dose rates resulting from nuclear criticality accidents. The original slide rules were created for highly enriched uranium solutions and metals using hand calculations along with the decades old Way-Wigner radioactive decay relationship and the inverse square law. This work uses state-of-the-art methods and better data to improve the original slide rules and also to extend the slide rule concept to three additional systems; i.e., highly enriched (93.2 wt%) uranium damp (H/235U = 10) powder (U3O8) and low-enriched (5 wt%) uranium mixtures (UO2F2) with a H/235U ratio of 200 and 500. Although the improved slide rules differ only slightly from the original slide rules, the improved slide rules and also the new slide rules can be used with greater confidence since they are based on more rigorous methods and better nuclear data

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

    International Nuclear Information System (INIS)

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

  12. A Mathematical Model for Estimating Biological Damage Caused by Radiation

    CERN Document Server

    Manabe, Yuichiro; Bando, Masako

    2012-01-01

    We propose a mathematical model for estimating biological damage caused by low-dose irradiation. We understand that the Linear Non Threshold (LNT) hypothesis is realized only in the case of no recovery effects. In order to treat the realistic living objects, our model takes into account various types of recovery as well as proliferation mechanism, which may change the resultant damage, especially for the case of lower dose rate irradiation. It turns out that the lower the radiation dose rate, the safer the irradiated system of living object (which is called symbolically "tissue" hereafter) can have chances to survive, which can reproduce the so-called dose and dose-rate effectiveness factor (DDREF).

  13. A Mathematical Model for Estimating Biological Damage Caused by Radiation

    Science.gov (United States)

    Manabe, Yuichiro; Ichikawa, Kento; Bando, Masako

    2012-10-01

    We propose a mathematical model for estimating biological damage caused by low-dose irradiation. We understand that the linear non threshold (LNT) hypothesis is realized only in the case of no recovery effects. In order to treat the realistic living objects, our model takes into account various types of recovery as well as proliferation mechanism, which may change the resultant damage, especially for the case of lower dose rate irradiation. It turns out that the lower the radiation dose rate, the safer the irradiated system of living object (which is called symbolically ``tissue'' hereafter) can have chances to survive, which can reproduce the so-called dose and dose-rate effectiveness factor (DDREF).

  14. Biological equivalent dose studies for dose escalation in the stereotactic synchrotron radiation therapy clinical trials

    International Nuclear Information System (INIS)

    Synchrotron radiation is an innovative tool for the treatment of brain tumors. In the stereotactic synchrotron radiation therapy (SSRT) technique a radiation dose enhancement specific to the tumor is obtained. The tumor is loaded with a high atomic number (Z) element and it is irradiated in stereotactic conditions from several entrance angles. The aim of this work was to assess dosimetric properties of the SSRT for preparing clinical trials at the European Synchrotron Radiation Facility (ESRF). To estimate the possible risks, the doses received by the tumor and healthy tissues in the future clinical conditions have been calculated by using Monte Carlo simulations (PENELOPE code). The dose enhancement factors have been determined for different iodine concentrations in the tumor, several tumor positions, tumor sizes, and different beam sizes. A scheme for the dose escalation in the various phases of the clinical trials has been proposed. The biological equivalent doses and the normalized total doses received by the skull have been calculated in order to assure that the tolerance values are not reached.

  15. Dose estimation for paediatric cranial computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Curci Daros, K.A.; Bitelli Medeiros, R. [Sao Paulo Univ. Federal (Brazil); Curci Daros, K.A.; Oliveira Echeimberg, J. de [Centro Univ. Sao Camilo, Sao Paulo (Brazil)

    2006-07-01

    region defined by position 6.0dose was 11.3(3.3) mGy. Eye region calculated dose was 0.4(0.1) mGy. Conclusion: Thermoluminescent dosimetry can be used in determining integral patient absorbed dose distribution in the three cranial regions under different X-ray exposure conditions. The proposed function permitted dose estimation in cranial paediatric exams independent of mAs because maximum T.L readings were determined in the supratentorial region, maintaining the above-mentioned operational and geometrical conditions. (authors)

  16. A Bayesian Dose-finding Design for Oncology Clinical Trials of Combinational Biological Agents.

    Science.gov (United States)

    Cai, Chunyan; Yuan, Ying; Ji, Yuan

    2014-01-01

    Treating patients with novel biological agents is becoming a leading trend in oncology. Unlike cytotoxic agents, for which efficacy and toxicity monotonically increase with dose, biological agents may exhibit non-monotonic patterns in their dose-response relationships. Using a trial with two biological agents as an example, we propose a dose-finding design to identify the biologically optimal dose combination (BODC), which is defined as the dose combination of the two agents with the highest efficacy and tolerable toxicity. A change-point model is used to reflect the fact that the dose-toxicity surface of the combinational agents may plateau at higher dose levels, and a flexible logistic model is proposed to accommodate the possible non-monotonic pattern for the dose-efficacy relationship. During the trial, we continuously update the posterior estimates of toxicity and efficacy and assign patients to the most appropriate dose combination. We propose a novel dose-finding algorithm to encourage sufficient exploration of untried dose combinations in the two-dimensional space. Extensive simulation studies show that the proposed design has desirable operating characteristics in identifying the BODC under various patterns of dose-toxicity and dose-efficacy relationships. PMID:24511160

  17. Biological effective doses in the intracavitary high dose rate brachytherapy of cervical cancer

    Directory of Open Access Journals (Sweden)

    Y. Sobita Devi

    2011-12-01

    Full Text Available Purpose: The aim of this study is to evaluate the decrease of biological equivalent dose and its correlation withlocal/loco-regional control of tumour in the treatment of cervical cancer when the strength of the Ir-192 high dose rate(HDR brachytherapy (BT source is reduced to single, double and triple half life in relation to original strength of10 Ci (~ 4.081 cGy x m2 x h–1. Material and methods: A retrospective study was carried out on 52 cervical cancer patients with stage II and IIItreated with fractionated HDR-BT following external beam radiation therapy (EBRT. International Commission onRadiation Units and Measurement (ICRU points were defined according to ICRU Report 38, using two orthogonal radiographimages taken by Simulator (Simulix HQ. Biologically effective dose (BED was calculated at point A for diffe -rent Ir-192 source strength and its possible correlation with local/loco-regional tumour control was discussed. Result: The increase of treatment time per fraction of dose due to the fall of dose rate especially in HDR-BT of cervicalcancer results in reduction in BED of 2.59%, 7.02% and 13.68% with single, double and triple half life reduction ofsource strength, respectively. The probabilities of disease recurrence (local/loco-regional within 26 months are expectedas 0.12, 0.12, 0.16, 0.39 and 0.80 for source strength of 4.081, 2.041, 1.020, 0.510 and 0.347 cGy x m2 x h–1, respectively.The percentages of dose increase required to maintain the same BED with respect to initial BED were estimated as1.71, 5.00, 11.00 and 15.86 for the dose rate of 24.7, 12.4, 6.2 and 4.2 Gy/hr at point A, respectively. Conclusions: This retrospective study of cervical cancer patients treated with HDR-BT at different Ir-192 sourcestrength shows reduction in disease free survival according to the increase in treatment time duration per fraction.The probable result could be associated with the decrease of biological equivalent dose to point A. Clinical

  18. Can results from animal studies be used to estimate dose or low dose effects in humans

    International Nuclear Information System (INIS)

    We have devised a method to extrapolate biological equilibrium levels between animal species and subsequently to humans. Our initial premise was based on the observation that radionuclide retention is normally a function of metabolism so that direct or indirect measures could be described by a power law based on body weights of test animal species. However, we found that such interspecies comparisons ought to be based on the coefficient of the power equation rather than on the exponential parameter. The method is illustrated using retention data obtained from five non-ruminant species (including humans) that were fed radionuclides with different properties. It appears that biological equilibrium level for radionuclides in man can be estimated using data from mice, rats and dogs. The need to extrapolate low-dose effects data obtained from small animals (usually rodents) to humans is not unique to radiation dosimetry or radiation protection problems. Therefore, researchers have reviewed some quantitative problems connected with estimating low-dose effects from other disciplines, both because of the concern about effects induced by the radionuclide moiety of a radiopharmaceutical and those of the nonradioactive component. The possibility of extrapolating low-dose effects calculated from animal studies to humans is discussed

  19. Can results from animal studies be used to estimate dose or low dose effects in humans

    International Nuclear Information System (INIS)

    A method has been devised to extrapolate biological equilibrium levels between animal species and subsequently to humans. Our initial premise was based on the observation that radionuclide retention is normally a function of metabolism so that direct or indirect measures could be described by a power law based on body weights of test animal species. However, we found that such interspecies comparisons ought to be based on the coefficient of the power equation rather than on the exponential parameter. The method is illustrated using retention data obtained from five non-ruminant species (including humans) that were fed radionuclides with different properties. It appears that biological equilibrium level for radionuclides in man can be estimated using data from mice, rats, and dogs. The need to extrapolate low-dose effects data obtained from small animals (usually rodents) to humans is not unique to radiation dosimetry or radiation protection problems. Therefore, some quantitative problems connected with estimating low-dose effects from other disciplines have been reviewed, both because of the concern about effects induced by the radionuclide moiety of a radiopharmaceutical and those of the nonradioactive component. The possibility of extrapolating low-dose effects calculated from animal studies to human is discussed

  20. Biological effects of low-dose ionizing radiation exposure

    International Nuclear Information System (INIS)

    The report on the meeting of the Strahlenschutzkommission 2007 concerning biological effects of low-dose ionizing radiation exposure includes the following contributions: Adaptive response. The importance of DNA damage mechanisms for the biological efficiency of low-energy photons. Radiation effects in mammography: the relative biological radiation effects of low-energy photons. Radiation-induced cataracts. Carcinomas following prenatal radiation exposure. Intercellular apoptosis induction and low-dose irradiation: possible consequences for the oncogenesis control. Mechanistic models for the carcinogenesis with radiation-induced cell inactivation: application to all solid tumors in the Japanese atomic bomb survivors. Microarrays at low radiation doses. Mouse models for the analysis of biological effects of low-dose ionizing radiation. The bystander effect: observations, mechanisms and implications. Lung carcinoma risk of Majak workers - modeling of carcinogenesis and the bystander effect. Microbeam studies in radiation biology - an overview. Carcinogenesis models with radiation-induced genomic instability. Application to two epidemiological cohorts.

  1. Doses and biological effect of ionizing radiation

    International Nuclear Information System (INIS)

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

  2. Dose-painting IMRT optimization using biological parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yusung (Dept. of Radiation Oncology, Univ. of Iowa, Iowa City (United States)); Tome, Wolfgang A. (Dept. of Human Oncology Univ. of Wisconsin, Madison (United States)), E-mail: tome@humonc.wisc.edu

    2010-11-15

    Purpose. Our work on dose-painting based on the possible risk characteristics for local recurrence in tumor subvolumes and the optimization of treatment plans using biological objective functions that are region-specific are reviewed. Materials and methods. A series of intensity modulated dose-painting techniques are compared to their corresponding intensity modulated plans in which the entire PTV is treated to a single dose level, delivering the same equivalent uniform dose (EUD) to the entire PTV. Iso-TCP and iso-NTCP maps are introduced as a tool to aid the planner in the evaluation of the resulting non-uniform dose distributions. Iso-TCP and iso-NTCP maps are akin to iso-dose maps in 3D conformal radiotherapy. The impact of the currently limited diagnostic accuracy of functional imaging on a series of dose-painting techniques is also discussed. Results. Utilizing biological parameters (risk-adaptive optimization) in the generation of dose-painting plans results in an increase in the therapeutic ratio as compared to conventional dose-painting plans in which optimization techniques based on physical dose are employed. Conclusion. Dose-painting employing biological parameters appears to be a promising approach for individualized patient- and disease-specific radiotherapy

  3. Dose-painting IMRT optimization using biological parameters

    International Nuclear Information System (INIS)

    Purpose. Our work on dose-painting based on the possible risk characteristics for local recurrence in tumor subvolumes and the optimization of treatment plans using biological objective functions that are region-specific are reviewed. Materials and methods. A series of intensity modulated dose-painting techniques are compared to their corresponding intensity modulated plans in which the entire PTV is treated to a single dose level, delivering the same equivalent uniform dose (EUD) to the entire PTV. Iso-TCP and iso-NTCP maps are introduced as a tool to aid the planner in the evaluation of the resulting non-uniform dose distributions. Iso-TCP and iso-NTCP maps are akin to iso-dose maps in 3D conformal radiotherapy. The impact of the currently limited diagnostic accuracy of functional imaging on a series of dose-painting techniques is also discussed. Results. Utilizing biological parameters (risk-adaptive optimization) in the generation of dose-painting plans results in an increase in the therapeutic ratio as compared to conventional dose-painting plans in which optimization techniques based on physical dose are employed. Conclusion. Dose-painting employing biological parameters appears to be a promising approach for individualized patient- and disease-specific radiotherapy

  4. Biological effects at low irradiation doses

    International Nuclear Information System (INIS)

    Full text: The best scientific evidence of radiation effects in humans initially came from epidemiological studies of atomic bomb survivors in Hiroshima and Nagasaki. While no evidence of genetic effects has been found, these studies showed a roughly linear relationship between the induction of cancer and extremely high dose-rate of atomic bomb radiation. This was consistent with the knowledge that ionizing radiation can damage DNA in linear proportion to high-dose exposures and so produces gene mutations known to be associated with cancer. In the absence of comparable low dose effects it was prudent to propose tentatively the no-threshold hypothesis (LNT) that extrapolates linearly from effects observed at very high doses to the same effects at very low doses. It was accepted by the International Commission on Radiological Protection (ICRP) and afterwards adopted by national radiation protection organizations to guide regulations for the protection of occupationally exposed workers and the public. This hypothesis that all radiation is harmful in linear proportion to the dose is the principle used for collective dose calculations of the number of deaths produced by any radiation, natural of generated, no matter how small (BEIR-2000). The National Council of Radiation Protection and Measurements Report 121, summarizes the basis for adherence to linearity of radiation health effects. Confidence in LNT at low doses is based on our understanding of the basic mechanisms involved. Genetic effects may result from a gene mutation or a chromosome aberration. The activation of a dominant acting oncogene is frequently associated with leukemia and lymphomas, while the loss of suppressor genes appears to be more frequently associated with solid tumors. It is conceptually possible, but with a vanishing small probability, that any of these effects could result from the passage of a single charged particle, causing damage to DNA that could be expressed as a mutation or small

  5. SWEET CORN CULTIVAR INFLUENCES BIOLOGICALLY EFFECTIVE HERBICIDE DOSE [ABSTRACT

    Science.gov (United States)

    Competitive crop cultivars are considered a component of integrated weed management systems; however specific knowledge of interactions among crop cultivars and other management tactics, such as biologically effective herbicide dose, is limited. Observed variation in crop tolerance and weed supp...

  6. Strategies for Biologic Image-Guided Dose Escalation: A Review

    International Nuclear Information System (INIS)

    There is increasing interest in how to incorporate functional and molecular information obtained by noninvasive, three-dimensional tumor imaging into radiotherapy. The key issues are to identify radioresistant regions that can be targeted for dose escalation, and to develop radiation dose prescription and delivery strategies providing optimal treatment for the individual patient. In the present work, we review the proposed strategies for biologic image-guided dose escalation with intensity-modulated radiation therapy. Biologic imaging modalities and the derived images are discussed, as are methods for target volume delineation. Different dose escalation strategies and techniques for treatment delivery and treatment plan evaluation are also addressed. Furthermore, we consider the need for response monitoring during treatment. We conclude with a summary of the current status of biologic image-based dose escalation and of areas where further work is needed for this strategy to become incorporated into clinical practice

  7. Dosimetry in Interventional Radiology - Effective Dose Estimation

    International Nuclear Information System (INIS)

    Interventional radiological procedures can lead to significant radiation doses to patients and to staff members. In order to evaluate the personal doses with respect to the regulatory dose limits, doses measured by dosimeters have to be converted to effective doses (E). Measurement of personal dose equivalent Hp(10) using a single unshielded dosimeter above the lead apron can lead to significant overestimation of the effective dose, while the measurement with dosimeter under the apron can lead to underestimation. To improve the accuracy, measurements with two dosimeters, one above and the other under the apron have been suggested (double dosimetry). The ICRP has recommended that interventional radiology departments develop a policy that staff should wear two dosimeters. The aim of this study was to review the double dosimetry algorithms for the calculation of effective dose in high dose interventional radiology procedures. The results will be used to develop general guidelines for personal dosimetry in interventional radiology procedures. This work has been carried out by Working Group 9 (Radiation protection dosimetry of medical staff) of the CONRAD project, which is a Coordination Action supported by the European Commission within its 6th Framework Program.(author)

  8. Coincidence in the dose estimation in a OEP by different methods

    International Nuclear Information System (INIS)

    The case of an apparent overexposure to radiation according to that indicated for the thermoluminescent dosemeter 81.59 mSv (TLD) of a occupationally exposed hard-working (POE), for that was practiced the study of biological dosimetry. The estimated dose was 0.12 Gy with which was proven the marked dose registration by the TLD dosemeter. It was concluded that both doses are the same ones. (Author)

  9. Are there dangers in biologic dose reduction strategies?

    Science.gov (United States)

    Chan, Christopher K Y; Holroyd, Christopher R; Mason, Alice; Zarroug, Jalaa; Edwards, Christopher J

    2016-07-01

    Biologic dose reduction strategies, for patients with inflammatory rheumatic diseases, have been assessed in multiple studies to assess outcomes compared to ongoing maintenance dosing. Whilst cessation in established disease usually leads to disease flare, dose tapering approaches for those achieving low disease activity often appear to be successful in the short term. However, tapering can be associated with a higher risk of losing disease control and rates of recapture of disease control using the original biologic dose vary between studies. Over relatively short periods of follow-up, a number of studies have shown no statistical difference in radiographic progression in patients tapering or discontinuing biologics. However, a Cochrane review found that radiographic and functional outcomes may be worse after TNF inhibitor discontinuation, and over long-term disease follow-up flares have been associated with radiographic progression and worse patient reported outcomes. To date, no studies of biological therapy dose reduction have specifically investigated the risk of increased immunogenicity or the effects on cardiovascular risk and other co-morbidities, although these remain important potential risks. In addition, whether there are greater dangers in certain dose reduction approaches such as a reduction in dose at the same frequency or a spacing of doses is not established. PMID:26970488

  10. Estimation of radiation risks at low dose

    International Nuclear Information System (INIS)

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

  11. Relationship between biologic tissue heterogeneity and absorbed dose distribution in therapy of oncologic patients with cyclotron U-120 fast neutrons

    International Nuclear Information System (INIS)

    Effect of biological tissue heterogeneity on the absorbed dose distribution of U-120 cyclotron fast neutron beam was studied by estimation and experimental method. It was found that adipose and bone tissues significantly changes the pattern of neutron absorbed dose distribution in patient body. Absorbed dose in adipose layer increase by 20% as compared to the dose in soft biological tissue. Approximation method for estimation of the absorbed dose distribution of fast neutrons in heterogeneities was proposed which could be applied in the dosimetric planning of U-120 cyclotron neutron therapy of neoplasms

  12. Ingestion of Nevada Test Site Fallout: Internal dose estimates

    International Nuclear Information System (INIS)

    This paper summarizes individual and collective dose estimates for the internal organs of hypothetical yet representative residents of selected communities that received measurable fallout from nuclear detonations at the Nevada Test Site. The doses, which resulted from ingestion of local and regional food products contaminated with over 20 radionuclides, were estimated with use of the PATHWAY food-chain-transport model to provide estimates of central tendency and uncertainty. The thyroid gland received much higher doses than other internal organs and tissues. In a avery few cases, infants might have received thyroid doses in excess of 1 Gy, depending on location, diet, and timing of fallout. 131I was the primary thyroid dose contributor, and fresh milk was the main exposure pathway. With the exception of the thyroid, organ doses from the ingestion pathway were much smaller (<3%) than those from external gamma exposure to deposited fallout. Doses to residents living closest to the Nevada Test Site were contributed mainly by a few fallout events; doses to more distantly located people were generally smaller, but a greater number of events provided measurable contributions. The effectiveness of different fallout events in producing internal organ doses through ingestion varied dramatically with seasonal timing of the test, with maximum dose per unit fallout occurring for early summer depositions when milk cows were on pasture and fresh, local vegetables were used. Within specific communities, internal doses differed by age, sex, and lifestyle. Collective internal dose estimates for specific geographic areas are provided

  13. Occupational dose estimates for a monitored retrievable storage facility

    International Nuclear Information System (INIS)

    Occupational doses were estimated for radiation workers at the monitored retrievable storage (MRS) facility. This study provides an estimate of the occupational dose based on the current MRS facility design, examines the extent that various design parameters and assumptions affect the dose estimates, and identifies the areas and activities where exposures can be reduced most effectively. Occupational doses were estimated for both the primary storage concept and the alternate storage concept. The dose estimates indicate the annual dose to all radiation workers will be below the 5 rem/yr federal dose equivalent limit. However, the estimated dose to most of the receiving and storage crew (the workers responsible for the receipt, storage, and surveillance of the spent fuel and its subsequent retrieval), to the crane maintenance technicians, and to the cold and remote maintenance technicians is above the design objective of 1 rem/yr. The highest annual dose is received by the riggers (4.7 rem) in the receiving and storage crew. An indication of the extent to which various design parameters and assumptions affect the dose estimates was obtained by changing various design-based assumptions such as work procedures, background dose rates in radiation zones, and the amount of fuel received and stored annually. The study indicated that a combination of remote operations, increased shielding, and additional personnel (for specific jobs) or changes in operating procedures will be necessary to reduce worker doses below 1.0 rem/yr. Operations that could be made at least partially remote include the removal and replacement of the tiedowns, impact limiters, and personnel barriers from the shipping casks and the removal or installation of the inner closure bolts. Reductions of the background dose rates in the receiving/shipping and the transfer/discharge areas may be accomplished with additional shielding

  14. Estimation of the integral dose of neutrons using monitoring data

    International Nuclear Information System (INIS)

    The Japan Atomic Energy Research Institute's Labor Union estimated the integrated dose of neutrons using the monitoring data immediately after the JCO accident. The integral doses at 13 points located on the external boundary of the JCO site were estimated. As a result of regression analysis, it was calculated that the integral dose at the 350 m point, which was the limit for evacuation decided by the chief of the village, was about 2 mSv

  15. Modelling the Influence of Shielding on Physical and Biological Organ Doses

    CERN Document Server

    Ballarini, Francesca; Ferrari, Alfredo; Ottolenghi, Andrea; Pelliccioni, Maurizio; Scannicchio, Domenico

    2002-01-01

    Distributions of "physical" and "biological" dose in different organs were calculated by coupling the FLUKA MC transport code with a geometrical human phantom inserted into a shielding box of variable shape, thickness and material. While the expression "physical dose" refers to the amount of deposited energy per unit mass (in Gy), "biological dose" was modelled with "Complex Lesions" (CL), clustered DNA strand breaks calculated in a previous work based on "event-by-event" track-structure simulations. The yields of complex lesions per cell and per unit dose were calculated for different radiation types and energies, and integrated into a version of FLUKA modified for this purpose, allowing us to estimate the effects of mixed fields. As an initial test simulation, the phantom was inserted into an aluminium parallelepiped and was isotropically irradiated with 500 MeV protons. Dose distributions were calculated for different values of the shielding thickness. The results were found to be organ-dependent. In most ...

  16. Estimation of neutron doses in Hiroshima and Nagasaki atomic bombings

    International Nuclear Information System (INIS)

    For the radiation doses in the Hiroshima and the Nagasaki atomic bombings, the estimated values of T65D (in the United States) have been used. In recent years, however, these values are being restudied. On the basis of the neutron spectra from atomic bombings published from LANL in 1976, the neutron doses in the Hiroshima and Nagasaki atomic bombings were estimated. It was pointed out that the neutron doses of T65D were overestimated. The results of calculation in this estimation were that at the distance from 1 km to 2 km, the neutron doses in Hiroshima and Nagasaki were from 1/5 to 1/9 and about 1/3, respectively, as compared with those in T65D. The estimation of the neutron doses in the atomic bombings by calculation, the difference from T65D and the comparison with the measured radioactivities immediately after atomic bombings are described. (Mori, K.)

  17. Cellular vs. organ approaches to dose estimates

    International Nuclear Information System (INIS)

    The cellular distribution of tissue-incorporated radionuclides has generally been neglected in the dosimetry of internal emitters. Traditional dosimetry assumes homogeneous distribution of radionuclides in organs of interest, while presuming that the ranges of particulate radiations are large relative to typical cell diameters. The macroscopic distribution of dose thus calculated has generally served as a sufficient approximation for the energy deposited within radiosensitive sites. However, with the increasing utilization of intracellular agents, such as thallium-201, it has become necessary to examine the microscopic distribution of energy at the cellular level. This is particularly important in the instance of radionuclides that decay by electron capture or by internal conversion with the release of Auger and Coster-Kronig electrons. In many instances, these electrons are released as a dense shower of low-energy particles with ranges of subcellular dimensions. The high electron density in the immediate vicinity of the decaying atom produces a focal deposition of energy that far exceeds the average dose taken over several cell diameters. These studies point out the increasing need to take into account the microscopic distribution of dose on the cellular level as radionuclides distributed in cells become more commonplace, especially if the decay involves electron capture or internal conversion. As radiotracers are developed for the measurement of intracellular functions these factors should be given greater consideration. 16 references, 5 figures, 5 tables

  18. Molecular circuits, biological switches, and nonlinear dose-response relationships.

    OpenAIRE

    Andersen, Melvin E.; Yang, Raymond S.H.; French, C. Tenley; Chubb, Laura S; Dennison, James E

    2002-01-01

    Signaling motifs (nuclear transcriptional receptors, kinase/phosphatase cascades, G-coupled protein receptors, etc.) have composite dose-response behaviors in relation to concentrations of protein receptors and endogenous signaling molecules. "Molecular circuits" include the biological components and their interactions that comprise the workings of these signaling motifs. Many of these molecular circuits have nonlinear dose-response behaviors for endogenous ligands and for exogenous toxicants...

  19. Methodology for Estimating Ingestion Dose for Emergency Response at SRS

    International Nuclear Information System (INIS)

    At the Savannah River Site (SRS), emergency response computer models are used to estimate dose following releases of radioactive materials to the environment. Downwind air and ground concentrations and their associated doses from inhalation and ground shine pathways are estimated. The emergency response model (PUFF-PLUME) uses real-time data to track either instantaneous (puff) or continuous (plume) releases. A site-specific ingestion dose model was developed for use with PUFF-PLUME that includes the following ingestion dose pathways pertinent to the surrounding SRS area: milk, beef, water, and fish. The model is simplistic and can be used with existing code output

  20. Dose estimation in embryo or fetus in external fields

    International Nuclear Information System (INIS)

    The embryo or the fetus can be irradiated as result of radiological procedures of diagnosis of therapy in where the beam effects directly on the same one or in tissues or peripherical organs. Some authors have suggested that in the first stages of the pregnancy the dose in ovaries can be the good estimated of the dose in embryo or fetus. In advanced conditions of the development, probably also in the early stage, is more appropriated to specify the dose in the embryo or fetus equal of the uterus. The dose in the uterus is a good estimated so much for external irradiation as for radionuclides incorporation

  1. Fetal dose estimates for radiotherapy of brain tumors during pregnancy

    International Nuclear Information System (INIS)

    Purpose: To determine clinically the fetal dose from irradiation of brain tumors during pregnancy and to quantitate the components of fetal dose using phantom measurements. Methods and Materials: Two patients received radiotherapy during pregnancy for malignant brain tumors. Case 1 was treated with opposed lateral blocked 10 x 15 cm fields and case 2 with 6 x 6 cm bicoronal wedged arcs, using 6 MV photons. Fetal dose was measured clinically and confirmed with phantom measurements using thermoluminescent dosimeters (TLDs). Further phantom measurements quantitated the components of scattered dose. Results: For case 1, both clinical and phantom measurements estimated fetal dose to be 0.09% of the tumor dose, corresponding to a total fetal dose of 0.06 Gy for a tumor dose of 68.0 Gy. Phantom measurements estimated that internal scatter contributed 20% of the fetal dose, leakage 20%, collimator scatter 33%, and block scatter 27%. For case 2, clinical and phantom measurements estimated fetal dose to be 0.04% of the tumor dose, corresponding to a total fetal dose of 0.03 Gy for a tumor dose of 78.0 Gy. Leakage contributed 74% of the fetal dose, internal scatter 13%, collimator scatter 9%, and wedge scatter 4%. Conclusions: When indicated, brain tumors may be irradiated to high dose during pregnancy resulting in fetal exposure < 0.10 Gy, conferring an increased but acceptable risk of leukemia in the child, but no other deleterious effects to the fetus after the fourth week of gestation. For our particular field arrangements and linear accelerators, internal scatter contributed a small component of fetal dose compared to leakage and scatter from the collimators and blocks, and 18 MV photons resulted in a higher estimated fetal dose than 6 MV photons due to increased leakage and collimator scatter. These findings are not universal, but clinical and phantom TLD measurements estimate fetal dose accurately for energies < 10 MV and should be taken for each pregnant patient

  2. Adult head CT scans: the uncertainties of effective dose estimates

    International Nuclear Information System (INIS)

    Full Text: CT scanning is a high dose imaging modality. Effective dose estimates from CT scans can provide important information to patients and medical professionals. For example, medical practitioners can use the dose to estimate the risk to the patient, and judge whether this risk is outweighed by the benefits of the CT examination, while radiographers can gauge the effect of different scanning protocols on the patient effective dose, and take this into consideration when establishing routine scan settings. Dose estimates also form an important part of epidemiological studies examining the health effects of medical radiation exposures on the wider population. Medical physicists have been devoting significant effort towards estimating patient radiation doses from diagnostic CT scans for some years. The question arises: How accurate are these effective dose estimates? The need for a greater understanding and improvement of the uncertainties in CT dose estimates is now gaining recognition as an important issue (BEIR VII 2006). This study is an attempt to analyse and quantify the uncertainty components relating to effective dose estimates from adult head CT examinations that are calculated with four commonly used methods. The dose estimation methods analysed are the Nagel method, the ImpaCT method, the Wellhoefer method and the Dose-Length Product (DLP) method. The analysis of the uncertainties was performed in accordance with the International Standards Organisation's Guide to the Expression of Uncertainty in Measurement as discussed in Gregory et al (Australas. Phys. Eng. Sci. Med., 28: 131-139, 2005). The uncertainty components vary, depending on the method used to derive the effective dose estimate. Uncertainty components in this study include the statistical and other errors from Monte Carlo simulations, uncertainties in the CT settings and positions of patients in the CT gantry, calibration errors from pencil ionization chambers, the variations in the organ

  3. Biological effects and equivalent doses in radiotherapy: a software solution

    CERN Document Server

    Voyant, Cyril; Roustit, Rudy; Biffi, Katia; Marcovici, Celine Lantieri

    2013-01-01

    The limits of TDF (time, dose, and fractionation) and linear quadratic models have been known for a long time. Medical physicists and physicians are required to provide fast and reliable interpretations regarding the delivered doses or any future prescriptions relating to treatment changes. We therefore propose a calculation interface under the GNU license to be used for equivalent doses, biological doses, and normal tumor complication probability (Lyman model). The methodology used draws from several sources: the linear-quadratic-linear model of Astrahan, the repopulation effects of Dale, and the prediction of multi-fractionated treatments of Thames. The results are obtained from an algorithm that minimizes an ad-hoc cost function, and then compared to the equivalent dose computed using standard calculators in seven French radiotherapy centers.

  4. Dose estimates in Japan following the Chernobyl reactor accident

    International Nuclear Information System (INIS)

    Estimates have been made of the maximum individual doses and the collective doses in Japan following the Chernobyl reactor accident. Based on the measured data of ground deposition and radionuclide concentrations in air, raw milk, milk on sale and leafy vegetables, the doses from some significant radionuclides were calculated for 5 typical exposure pathways; cloudshine, groundshine, inhalation, ingestion of milk and leafy vegetables. The maximum effective dose equivalents for hypothetical individuals were calculated to be 1.8 mrem for adults, 3.7 mrem for children and 6.0 mrem for infants. The collective effective dose equivalent in Japan was estimated to be 5.8 x 104 man · rem; 0.50 mrem of the average dose per capita. (author)

  5. Model Averaging Software for Dichotomous Dose Response Risk Estimation

    Directory of Open Access Journals (Sweden)

    Matthew W. Wheeler

    2008-02-01

    Full Text Available Model averaging has been shown to be a useful method for incorporating model uncertainty in quantitative risk estimation. In certain circumstances this technique is computationally complex, requiring sophisticated software to carry out the computation. We introduce software that implements model averaging for risk assessment based upon dichotomous dose-response data. This software, which we call Model Averaging for Dichotomous Response Benchmark Dose (MADr-BMD, fits the quantal response models, which are also used in the US Environmental Protection Agency benchmark dose software suite, and generates a model-averaged dose response model to generate benchmark dose and benchmark dose lower bound estimates. The software fulfills a need for risk assessors, allowing them to go beyond one single model in their risk assessments based on quantal data by focusing on a set of models that describes the experimental data.

  6. Biological dosimetry: chromosomal aberration analysis for dose assessment

    International Nuclear Information System (INIS)

    In view of the growing importance of chromosomal aberration analysis as a biological dosimeter, the present report provides a concise summary of the scientific background of the subject and a comprehensive source of information at the technical level. After a review of the basic principles of radiation dosimetry and radiation biology basic information on the biology of lymphocytes, the structure of chromosomes and the classification of chromosomal aberrations are presented. This is followed by a presentation of techniques for collecting blood, storing, transporting, culturing, making chromosomal preparations and scaring of aberrations. The physical and statistical parameters involved in dose assessment are discussed and examples of actual dose assessments taken from the scientific literature are given

  7. Estimation of organ doses and risk from personnel monitoring data

    International Nuclear Information System (INIS)

    The study of occupationally exposed workers to radiation has been based on recorded annual radiation doses. Personal monitoring programs in Ghana use thermoluminescent dosimeter to measure the whole body radiation dose and not the actual dose to the organs and tissues. In this study, Bayesian Statistical model has been used to estimate the annual effective doses to the organs and tissues of radiation workers including red bone marrow, female breast, thyroid, ovary, testes, lung and skin. The organ doses averaged over a cohort of occupationally exposed workers were estimated from personal monitoring data over a period of five years. The results from the study shows that the skin is more susceptible to radiation with the highest mean dose of 1.15±0.59 mSv averaged over five years followed by the thyroid and the female breast with the mean dose of 0.90±0.46 mSv and 0.72±0.38 msV averaged over five years respectively. The red bone marrow, ovary and lungs received the lowest doses with the mean dose estimate of 0.12 ± 0.11 mSv, 0.20±0.10mSv and 0.39±0.19mSv averaged over five years respectively. The statistical analysis software, SPSS was used to analyze the recorded data. The estimated mean annual cancer risks using International Commission on Radiological protection publication 103 showed low estimate's as compared to the international reference levels. The study shows that the radiation doses are within the limits for occupational exposure indicating that medical facilities and techniques used are adequate and acceptable. (au)

  8. Collective effective dose equivalent, population doses and risk estimates from occupational exposures in Japan

    International Nuclear Information System (INIS)

    Collective dose equivalent and population dose from occupational exposures in Japan, 1988 were estimated on the basis of a nationwide survey. The survey was conducted on annual collective dose equivalents by sex, age group and type of radiation work for about 0.21 million workers except for the workers in nuclear power stations. The data on the workers in nuclear power stations were obtained from the official report of the Japan Nuclear Safety Commission. The total number of workers including nuclear power stations was estimated to be about 0.26 million. Radiation works were subdivided as follows: medical works including dental; non-atomic energy industry; research and education; atomic energy industry and nuclear power station. For the determination of effective dose equivalent and population dose, organ or tissue doses were measured with a phantom experiment. The resultant doses were compared with the doses previously calculated using a chord length technique and with data from ICRP publications. The annual collective effective dose equivalent were estimated to be about 21.94 person·Sv for medical workers, 7.73 person·Sv for industrial workers, 0.75 person·Sv for research and educational workers, 2.48 person·Sv for atomic energy industry and 84.4 person ·Sv for workers in nuclear power station. The population doses were calculated to be about 1.07 Sv for genetically significant dose, 0.89 Sv for leukemia significant dose and 0.42 Sv for malignant significant dose. The population risks were estimated using these population doses. (author)

  9. Estimation of inhalation doses from airborne releases using gross monitors

    International Nuclear Information System (INIS)

    Monitoring programs at most nuclear facilities involve continuous gross measurements supplemented by periodic isotopic analyses of release samples. The isotopic measurements are required to accurately assess the potential dose from the various effluent streams, but in between these measurements, one depends on the gross monitors to provide approximate indications of the dose. The effluent streams release a variety of nuclides, each with its own dose factor. This means that the relationship between the counting rate in a gross monitor and the potential dose of the effluent being monitored will depend on the isotopic composition of this release. If this composition changes, then the dose indicated by the gross monitor (calibrated for the original group of isotopes) may be significantly in error. The problem of indicating inhalation doses from gross monitoring of airborne releases is considered. In order for this type of monitor to accurately indicate dose, regardless of the isotopic makeup of a release, the analysis shows that its response to each isotope should be proportional to the dose factor of that isotope. These ideas are applied to the monitoring of air particulates using gross beta and gross gamma monitors. The study shows that the former more closely satisfies this condition and as a result, satisfactorily indicates the actual dose from reactor effluents, as determined from detailed isotopic data published in the literature. On the other hand, the gross gamma monitor, with its poorer fit to the condition, provided less than satisfactory accuracy in its dose estimates. In addition, a variety of other mathematical response functions were considered but their dose estimation capabilities were not much better than the straight beta response. The study shows that reasonably accurate dose estimates can be made using properly selected gross monitors, but that significant errors can result with improper ones. (author)

  10. The estimation of galactic cosmic ray penetration and dose rates

    Science.gov (United States)

    Burrell, M. O.; Wright, J. J.

    1972-01-01

    This study is concerned with approximation methods that can be readily applied to estimate the absorbed dose rate from cosmic rays in rads - tissue or rems inside simple geometries of aluminum. The present work is limited to finding the dose rate at the center of spherical shells or behind plane slabs. The dose rate is calculated at tissue-point detectors or for thin layers of tissue. This study considers cosmic-rays dose rates for both free-space and earth-orbiting missions.

  11. Estimation of dose to man from environmental tritium

    International Nuclear Information System (INIS)

    Factors important for characterization of tritium in environmental pathways leading to exposure of man are reviewed and quantification of those factors is discussed. Parameters characterizing the behavior of tritium in man are also subjected to review. Factors to be discussed include organic binding, bioaccumulation, quality factor and transmutation. A variety of models are presently in use to estimate dose to man from environmental releases of tritium. Results from four representative models are compared and discussed. Site-specific information is always preferable when parameterizing models to estimate dose to man. There may be significant differences in dose potential among geographic regions due to variable factors. An example of one such factor examined is absolute humidity. It is concluded that adequate methodologies exist for estimation of dose to man from environmental tritium although a number of areas are identified where additional tritium research is desirable

  12. Analysis of patient exposure dose for mammography. Estimation of average glandular dose in 1998 questionnaire

    International Nuclear Information System (INIS)

    Recently, patient exposure dose for mammography are varied because of a great demand for mammography, which non-palpable lesion can be detected, diffusion of special X-ray equipment, progress of CR and enlightenment or study on mammography in Japanese society of radiological technology. Therefore, the newest patient exposure dose obtained from '98 questionnaire carried out to the whole country in Japan was investigated. Furthermore, the average glandular dose based on '98 was compared with that of '93. The average glandular dose can be calculated from the product of the breast entrance skin exposure and DgN (the average glandular dose per unit entrance skin exposure). The breast entrance skin dose was estimated from the dose of 782 institutions in '98, which was calculated from data measured at 51 institutions in Tokai and Hokuriku area. DgN was used published table of 50% adipose-50% glandular breast composition and 4.2 cm breast thickness corresponding to measured half-value layer (HVL) on each tube voltages. Then, patient exposure dose for mammography was estimated from exposure condition (tube voltage, mAs value) obtained '98 questionnaire. The dose in '98 estimated 1.422 mGy was reduced that compared with in '93 estimated 1.610 mGy. The dose of '98 without grid was reduced about 30% of '93. The dose of 98 with grid was not any reduced than the dose of '93. However, the number of institution of '98 with grid was about 2.8 times than '93. The patient exposure dose for mammography was reduced approximately 10% during 5 years. There are probability that mammography with grid for guidance level will be 1.5 mGy. (author)

  13. Chest X ray effective doses estimation in computed radiography

    International Nuclear Information System (INIS)

    Conventional chest radiography is technically difficult because of wide in tissue attenuations in the chest and limitations of screen-film systems. Computed radiography (CR) offers a different approach utilizing a photostimulable phosphor. photostimulable phosphors overcome some image quality limitations of chest imaging. The objective of this study was to estimate the effective dose in computed radiography at three hospitals in Khartoum. This study has been conducted in radiography departments in three centres Advanced Diagnostic Center, Nilain Diagnostic Center, Modern Diagnostic Center. The entrance surface dose (ESD) measurement was conducted for quality control of x-ray machines and survey of operators experimental techniques. The ESDs were measured by UNFORS dosimeter and mathematical equations to estimate patient doses during chest X rays. A total of 120 patients were examined in three centres, among them 62 were males and 58 were females. The overall mean and range of patient dosed was 0.073±0.037 (0.014-0.16) mGy per procedure while the effective dose was 3.4±01.7 (0.6-7.0) mSv per procedure. This study compared radiation doses to patients radiographic examinations of chest using computed radiology. The radiation dose was measured in three centres in Khartoum- Sudan. The results of the measured effective dose showed that the dose in chest radiography was lower in computed radiography compared to previous studies.(Author)

  14. Estimation of Radiobiologic Parameters and Equivalent Radiation Dose of Cytotoxic Chemotherapy in Malignant Glioma

    International Nuclear Information System (INIS)

    Purpose: To determine the radiobiologic parameters for high-grade gliomas. Methods and Materials: The biologic effective dose concept is used to estimate the α/β ratio and K (dose equivalent for tumor repopulation/d) for high-grade glioma patients treated in a randomized fractionation trial. The equivalent radiation dose of temozolomide (Temodar) chemotherapy was estimated from another randomized study. The method assumes that the radiotherapy biologic effective dose is proportional to the adjusted radiotherapy survival duration of high-grade glioma patients. Results: The median tumor α/β and K estimate is 9.32 Gy and 0.23 Gy/d, respectively. Using the published surviving fraction after 2-Gy exposure (SF2) data, and the above α/β ratio, the estimated median α value was 0.077 Gy-1, β was 0.009 Gy-2, and the cellular doubling time was 39.5 days. The median equivalent biologic effective dose of temozolomide was 11.03 Gy9.3 (equivalent to a radiation dose of 9.1 Gy given in 2-Gy fractions). Random sampling trial simulations based on a cure threshold of 70 Gy in high-grade gliomas have shown the potential increase in tumor cure with dose escalation. Partial elimination of hypoxic cells (by chemical hypoxic cell sensitizers or carbon ion therapy) has suggested that considerable gains in tumor control, which are further supplemented by temozolomide, are achievable. Conclusion: The radiobiologic parameters for human high-grade gliomas can be estimated from clinical trials and could be used to inform future clinical trials, particularly combined modality treatments with newer forms of radiotherapy. Other incurable cancers should be studied using similar radiobiologic analysis

  15. Methodology for Estimating Ingestion Dose for Emergency Response at SRS

    CERN Document Server

    Simpkins, A A

    2002-01-01

    At the Savannah River Site (SRS), emergency response models estimate dose for inhalation and ground shine pathways. A methodology has been developed to incorporate ingestion doses into the emergency response models. The methodology follows a two-phase approach. The first phase estimates site-specific derived response levels (DRLs) which can be compared with predicted ground-level concentrations to determine if intervention is needed to protect the public. This phase uses accepted methods with little deviation from recommended guidance. The second phase uses site-specific data to estimate a 'best estimate' dose to offsite individuals from ingestion of foodstuffs. While this method deviates from recommended guidance, it is technically defensibly and more realistic. As guidance is updated, these methods also will need to be updated.

  16. Biological effect of Pulsed Dose Rate brachytherapy with stepping sources

    International Nuclear Information System (INIS)

    Purpose: To explore the possible increase of radiation effect in tissues irradiated by pulsed brachytherapy (PDR), for local tissue dose-rates between those 'averaged over the whole pulse' and the instantaneous high dose rates close to the dwell positions. An earlier publication (Fowler and Mount 1992) had shown that, for dose rates (averaged for the duration of the pulse) up to 3 Gy/h, little change of isoeffect doses from continuous low dose rate (CLDR) are expected, unless larger doses per fraction than 1 Gy are used, and especially if components of very rapid repair are present with half-times of less than about 0.5 hours. However, local and transient dose rates close to stepping sources can be up to several Gy per minute. Methods: Calculations were done assuming the linear quadratic formula for radiation damage, in which only the dose-squared term is subject to repair, at a constant exponential rate. The formula developed by Dale for fractionated low-dose-rate radiotherapy was used. A constant overall time of 140 hours and constant total dose of 70 Gy were assumed throughout, the continuous low dose-rate of 0.5 Gy/h (CLDR) providing the unitary standard effects for each PDR condition. Effects of dose-rates ranging from 4 Gy/h to 120 Gy/h (HDR at 2 Gy/min) were studied, and T (1(2)) from 4 minutes to 1.5 hours. Results: Curves are presented relating the ratio of increased biological effect (proportional to log cell kill) calculated for PDR relative to CLDR. Ratios as high as 1.5 can be found for large doses per pulse (> 1 Gy) at high instantaneous dose-rates if T (1(2)) in tissues is as short as a few minutes. The major influences on effect are dose per pulse, half-time of repair in the tissue, and - when T (1(2)) is short - the instantaneous dose-rate. Maximum ratios of PDR/CLDR effect occur when the dose-rate is such that pulse duration is approximately equal to T (1(2)) of repair. Results are presented for late-responding tissues, the differences from CLDR

  17. Estimation of the fetal dose by dose measurement during an irradiation of a parotid tumor

    International Nuclear Information System (INIS)

    The irradiation of a five months pregnant patient has been made for a right parotid attack. In conformation with the legislative texts relative to radiation protection ( publication 84 of the ICRP) an estimation of the dose received for the fetus has been led by dose measurement on phantom. With the dose limit ( 100 mGy) recommended in the publication 84 of the ICRP neither modification of the treatment nor abortion was necessary. (N.C.)

  18. Estimation of organ doses and effective doses in image-guided respiration-gated radiotherapy

    International Nuclear Information System (INIS)

    Dose conformity in thoracic and abdominal ion-beam radiotherapy is degraded by respiratory motion. To improve conformity, an image-guided respiration-gated system can be used in the treatment room. The purpose of this study was to estimate the organ doses and effective doses to patients from an image-guided respiration-gated system. Glass dosemeters were inserted into an adult anthropomorphic phantom and were attached to the surface on the phantom. The phantom was placed on the treatment couch, and the imaging dose from fluoroscopy was evaluated. In addition to the organ doses, the effective doses were also estimated according to the ICRP Publication 103. The irradiation time is over 3-5 min per beam angle. When image acquisition conditions were assumed for thoracic treatment, the effective doses and maximal skin doses were 0.48-0.79 mSv and 5.9-9.9 mGy, respectively. The estimated doses can be the base data for considering radiological protection in the radiotherapy. (authors)

  19. Estimating thyroid dose in pediatric CT exams from surface dose measurement

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the possibility of estimating pediatric thyroid doses from CT using surface neck doses. Optically stimulated luminescence dosimeters were used to measure the neck surface dose of 25 children ranging in ages between one and three years old. The neck circumference for each child was measured. The relationship between obtained surface doses and thyroid dose was studied using acrylic phantoms of various sizes and with holes of different depths. The ratios of hole-to-surface doses were used to convert patients' surface dose to thyroid dose. ImPACT software was utilized to calculate thyroid dose after applying the appropriate age correction factors. A paired t-test was performed to compare thyroid doses from our approach and ImPACT. The ratio of thyroid to surface dose was found to be 1.1. Thyroid doses ranged from 20 to 80 mGy. Comparison showed no statistical significance (p = 0.18). In addition, the average of surface dose variation along the z-axis in helical scans was studied and found to range between 5% (in 10 cm diameter phantom/24 mm collimation/pitch 1.0) and 8% (in 16 cm diameter phantom/12 mm collimation/pitch 0.7). We conclude that surface dose is an acceptable predictor for pediatric thyroid dose from CT. The uncertainty due to surface dose variability may be reduced if narrower collimation is used with a pitch factor close to 1.0. Also, the results did not show any effect of thyroid depth on the measured dose. (paper)

  20. Radiation dose estimates for typical piloted NTR lunar and Mars mission engine operations

    Energy Technology Data Exchange (ETDEWEB)

    Schnitzler, B.G. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Borowski, S.K. (National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center)

    1991-01-01

    The natural and manmade radiation environments to be encountered during lunar and Mars missions are qualitatively summarized. The computational methods available to characterize the radiation environment produced by an operating nuclear propulsion system are discussed. Mission profiles and vehicle configurations are presented for a typical all-propulsive, fully reusable lunar mission and for a typical all-propulsive Mars mission. Estimates of crew location biological doses are developed for all propulsive maneuvers. Post-shutdown dose rates near the nuclear engine are estimated at selected mission times. 15 refs., 4 figs.

  1. Dose evaluation and effective dose estimation from CT fluoroscopy-guided lung biopsy

    International Nuclear Information System (INIS)

    The development of computerized tomography (CT) has made CT fluoroscopy possible with real-time CT images. However examination are expected to have high medical and occupational exposures. Then, exposures to patients and operating and assisting physicians during the CT fluoroscopy-guided lung biopsy were estimated. And changes in the examination conditions to lower the dose were made. Patient exposure was measured using an anthropomorphic phantom by simulation of clinical examination conditions. The surface dose to the physician was measured during actual clinical examinations. The average effective dose for the patient was 34±22 mSv. The highest surface dose amounted to 1.9 Gy, although this was in a very narrow field. Patient doses could be reduced by a factor of 2.5-3 by changing examination methods while still retaining diagnostic quality. The highest dose to the operating physician was 10 mGy which was recorded on the back of the hand and the average effective dose was estimated as 5.99 μSv per 1-minute examination. Doses were reduced by about a factor of 50 by lowering the tube voltage from 120 kV to 80 kV and using a supplementary tool. The doses for assisting physicians were not significant. The exposure for physicians and patients was much affected by lowering the tube voltage used for fluoroscopy. Using a supplementary tool was effective for reducing the dose for physicians. (author)

  2. Dose Estimation from Daily and Weekly Dosimetry Data

    Energy Technology Data Exchange (ETDEWEB)

    Ostrouchov, G.

    2001-11-16

    Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses (yearly dose of record). It is usually assumed that the dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. In our previous work with weekly data, a probability distribution was used to describe an individual's dose during a specific period of time and statistical methods were developed for estimating it from weekly film dosimetry data. This study showed that the yearly dose of record systematically underestimates doses for Oak Ridge National Laboratory (ORNL) workers. This could result in biased estimates of dose-response coefficients and their standard errors. The results of this evaluation raise serious questions about the suitability of the yearly dose of record for direct use in low-dose studies of nuclear industry workers. Here, we extend our previous work to use full information in Pocket meter data and develop the Data Synthesis for Individual Dose Estimation (DSIDE) methodology. Although the DSIDE methodology in this study is developed in the context of daily and weekly data to produce a cumulative yearly dose estimate, in principle it is completely general and can be extended to other time period and measurement combinations. The new methodology takes into account the ''measurement error'' that is produced by the film and pocket-meter dosimetry systems, the biases introduced by policies that lead to recording left-censored doses as zeros, and other measurement and recording practices. The DSIDE method is applied to a sample of dose histories obtained from hard copy dosimetry records at ORNL for the years 1945 to 1955. First, the rigorous addition of daily pocket-meter information shows that the negative bias is generally more severe than was reported in our work based on weekly film data only, however, the

  3. Dose Estimation from Daily and Weekly Dosimetry Data

    International Nuclear Information System (INIS)

    Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses (yearly dose of record). It is usually assumed that the dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. In our previous work with weekly data, a probability distribution was used to describe an individual's dose during a specific period of time and statistical methods were developed for estimating it from weekly film dosimetry data. This study showed that the yearly dose of record systematically underestimates doses for Oak Ridge National Laboratory (ORNL) workers. This could result in biased estimates of dose-response coefficients and their standard errors. The results of this evaluation raise serious questions about the suitability of the yearly dose of record for direct use in low-dose studies of nuclear industry workers. Here, we extend our previous work to use full information in Pocket meter data and develop the Data Synthesis for Individual Dose Estimation (DSIDE) methodology. Although the DSIDE methodology in this study is developed in the context of daily and weekly data to produce a cumulative yearly dose estimate, in principle it is completely general and can be extended to other time period and measurement combinations. The new methodology takes into account the ''measurement error'' that is produced by the film and pocket-meter dosimetry systems, the biases introduced by policies that lead to recording left-censored doses as zeros, and other measurement and recording practices. The DSIDE method is applied to a sample of dose histories obtained from hard copy dosimetry records at ORNL for the years 1945 to 1955. First, the rigorous addition of daily pocket-meter information shows that the negative bias is generally more severe than was reported in our work based on weekly film data only, however, the amount of bias also varies

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  6. Estimation of eye lens doses received by pediatric interventional cardiologists

    International Nuclear Information System (INIS)

    Maximum Hp(0.07) dose to the eye lens received in a year by the pediatric interventional cardiologists has been estimated. Optically stimulated luminescence dosimeters were placed on the eyes of an anthropomorphic phantom, whose position in the room simulates the most common irradiation conditions. Maximum workload was considered with data collected from procedures performed in the Hospital. None of the maximum values obtained exceed the dose limit of 20 mSv recommended by ICRP

  7. Identification and dose estimation of irradiated onions by chromosomal studies

    International Nuclear Information System (INIS)

    Post-irradiation identification and imparted dose determination are very much required to build the consumer confidence and for appropriate enforcement of the technology by the food inspectors. Towards this end, chromosomal aberration studies were attempted. Onions irradiated to different doses of gamma radiation, viz., 30, 60, 90, 120 and 150 Gy were scored for various types of chromosomal aberrations. The aberrations were found to increase with the dose and maximum type of aberrations were observed at 150 Gy. Single minutes, followed by double minutes were found to have outnumbered the other types at all the doses of irradiation. Tetracentrics were observed only at 150 Gy. The proportion of dicentric chromosomes appeared to be the most reliable parameter to estimate the irradiation dose given to onions. (author)

  8. Patient absorbed radiation doses estimation related to irradiation anatomy

    International Nuclear Information System (INIS)

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

  9. Dose estimation of the THOR BNCT treatment room

    International Nuclear Information System (INIS)

    BNCT beam of Tsing Hua Open-pool Reactor (THOR) was designed and constructed since 1998. A treatment room for the newly modified THOR BNCT beam was constructed for the next clinical-stage trials in 2004. Dose distribution in a patient (or a phantom) is important as irradiated with the BNCT beam. The dose distributions for different type of radiations such as neutron and photons in the treatment room are strongly becoming the index or reference of success for a BNCT facility. An ART head phantom was placed in front of the THOR BNCT beam port and was irradiated. In each section of the head phantom, numbers of small holes are inside and separated uniformly. Dual detector: TLD-600 and TLD-700 chips were placed inside these holes within the phantom to distinct doses of neutron and photon. Besides, Dual-TLD chips were latticed placed in the horizontal plane of beam central axis, in the treatment room to estimate the spatial dose distribution of neutron and photon. Gold foils were assisted in TLD dose calibrations. Neutron and photon dose distributions in phantom and spatial dose distributions in the THOR BNCT treatment room were both estimated in this work. Testing and improvement in THOR BNCT beam were continuative during these years. Results of this work could be the reference and be helpful for the further clinical trials in nearly future. (author)

  10. Patient-specific dose estimation for pediatric chest CT

    International Nuclear Information System (INIS)

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (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. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ dose for

  11. Patient-specific dose estimation for pediatric chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P. [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Global Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin 53188 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham North Carolina 27710 (United States)

    2008-12-15

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (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. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ

  12. Biologically effective doses of postoperative radiotherapy in the prevention of keloids. Dose-effect relationship

    International Nuclear Information System (INIS)

    Purpose: To review the recurrence rates of keloids after surgical excision followed by radiotherapy, and to answer the question whether after normalization of the dose, a dose-effect relationship could be derived. Material and Methods: A literature search was performed to identify studies dealing with the efficacy of various irradiation regimes for the prevention of keloids after surgery. Biologically effective doses (BEDs) of the various irradiation regimens were calculated using the linear-quadratic concept. A distinction between recurrence rates of keloids in the face and neck region and those in other parts of the body was made. Results: 31 reports were identified with PubMed with the search terms keloids, surgery, radiation therapy, radiotherapy. 13 reports were excluded, because no link could be found between recurrence rate and dose, or if less than ten patients per dose group. The recurrence rate for surgery only was 50-80%. For BED values >10 Gy the recurrence rate decreased as a function of BED. For BED values >30 Gy the recurrence rate was <10%. For a given dose, the recurrence rates of keloids in the sites with high stretch tension were not significantly higher than in sites without stretch tension. Conclusion: The results of this study indicate that for effectively treating keloids postoperatively, a relatively high dose must be applied in a short overall treatment time. The optimal treatment probably is an irradiation scheme resulting in a BED value of at least 30 Gy. A BED value of 30 Gy can be obtained with, for instance, a single acute dose of 13 Gy, two fractions of 8 Gy two fractions of 8 Gy or three fractions of 6 Gy, or a single dose of 27 Gy at low dose rate. The radiation treatment should be administered within 2 days after surgery. (orig.)

  13. Estimation of cosmic ray dose in airplanes with pocket dosimeters

    International Nuclear Information System (INIS)

    0.4. It means that raw data of PDM-303 vary in proportion to raw data of PDM-101 while PDM-101 records only ionizing components. This is consistent with the hypothesis that neutron dose holds about a constant fraction, 40% in this case, of ionizing component dose. The obtained relationship can be suggested as an empirical formula which translates indicated neutron doses of the pocket dosimeter (PDM-303) to more realistic values. However, such a smooth relationship ironically implies that we do not have to use PDM-303 in estimating neutron dose when we have PDM-101. (author)

  14. Biological optimization of heterogeneous dose distributions in systemic radiotherapy

    International Nuclear Information System (INIS)

    The standard computational method developed for internal radiation dosimetry is the MIRD (medical internal radiation dose) formalism, based on the assumption that tumor control is given by uniform dose and activity distributions. In modern systemic radiotherapy, however, the need for full 3D dose calculations that take into account the heterogeneous distribution of activity in the patient is now understood. When information on nonuniform distribution of activity becomes available from functional imaging, a more patient specific 3D dosimetry can be performed. Application of radiobiological models can be useful to correlate the calculated heterogeneous dose distributions to the current knowledge on tumor control probability of a homogeneous dose distribution. Our contribution to this field is the introduction of a parameter, the F factor, already used by our group in studying external beam radiotherapy treatments. This parameter allows one to write a simplified expression for tumor control probability (TCP) based on the standard linear quadratic (LQ) model and Poisson statistics. The LQ model was extended to include different treatment regimes involving source decay, incorporating the repair 'μ' of sublethal radiation damage, the relative biological effectiveness and the effective 'waste' of dose delivered when repopulation occurs. The sensitivity of the F factor against radiobiological parameters (α,β,μ) and the influence of the dose volume distribution was evaluated. Some test examples for 131I and 90Y labeled pharmaceuticals are described to further explain the properties of the F factor and its potential applications. To demonstrate dosimetric feasibility and advantages of the proposed F factor formalism in systemic radiotherapy, we have performed a retrospective planning study on selected patient case. F factor formalism helps to assess the total activity to be administered to the patient taking into account the heterogeneity in activity uptake and dose

  15. Biological effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  17. Estimation of dose in irradiated chicken bone by ESR method

    International Nuclear Information System (INIS)

    The author studied the conditions needed to routinely estimate the radiation dose in chicken bone by repeated re-irradiation and measuring ESR signals. Chicken meat containing bone was γ-irradiated at doses of up to 3kGy, accepted as the commercially used dose. The results show that points in sample preparation and ESR measurement are as follows: Both ends of bone are cut off and central part of compact bone is used for experiment. To obtain accurate ESR spectrum, marrow should be scraped out completely. Sample bone fragments of 1-2mm particle size and ca.100mg are recommended to obtain stable and maximum signal. In practice, by re-irradiating up to 5kGy and extrapolating data of the signal intensity to zero using linear regression analysis, radiation dose is estimated. For example, in one experiment, estimated doses of chicken bones initially irradiated at 3.0kGy, 1.0kGy, 0.50kGy and 0.25kGy were 3.4kGy, 1.3kGy, 0.81kGy and 0.57kGy. (author)

  18. Estimation of dose in dental radiology exams in critical regions

    International Nuclear Information System (INIS)

    The objective of this paper is to estimate the values of doses, which are absorbed dose to the lens and thyroid in a dental X-ray. Thermoluminescence dosimeters were used, once they provide a reading of quality and effectiveness. This study was based on dental exams conducted in patients in order to estimate the dose that disperses to the lens of the eye and for the thyroid during an intraoral exam. Data collection took place in two institutions, one governmental, which had the device SELETRONIC 70X and other particular. This study showed that there is a considerable variation between the appliances. Using the appliance DABI 1070, there was a greater absorption of radiation in the right eye (values greater than 5 mGy) and a lower dose in the thyroid, and the Seletronic 70X presented an incidence of higher dose deposited in the skin and in other points there was a balance in the values. In the appliance SELETRONIC 70X, there was again a greater absorption of radiation in the right eye and a lower setting in the thyroid. The excessive dose, besides does not favor at all for the quality of radiograph, represents a risk for the patient who absorbs unnecessary and harmful radiation to the body

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

    International Nuclear Information System (INIS)

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

  20. Effect of radon measurement methods on dose estimation

    International Nuclear Information System (INIS)

    Different radon measurement methods were applied in the old and new buildings of the Turkish bath of Eger (Hungary), in order to elaborate a radon measurement protocol. Besides, measurements were also made concerning the radon and thoron short-lived decay products, gamma dose from external sources and water radon. The most accurate results for dose estimation were provided by the application of personal radon meters. Estimated annual effective doses from radon and its short-lived decay products in the old and new buildings, using 0.2 and 0.1 measured equilibrium factors, were 0.83 and 0.17 mSv, respectively. The effective dose from thoron short-lived decay products was only 5 % of these values. The respective external gamma radiation effective doses were 0.19 and 0.12 mSvy-1. Effective dose from the consumption of tap water containing radon was 0.05 mSvy-1, while in the case of spring water, it was 0.14 mSvy-1. (authors)

  1. Effect of radon measurement methods on dose estimation.

    Science.gov (United States)

    Kávási, Norbert; Kobayashi, Yosuke; Kovács, Tibor; Somlai, János; Jobbágy, Viktor; Nagy, Katalin; Deák, Eszter; Berhés, István; Bender, Tamás; Ishikawa, Tetsuo; Tokonami, Shinji; Vaupotic, Janja; Yoshinaga, Shinji; Yonehara, Hidenori

    2011-05-01

    Different radon measurement methods were applied in the old and new buildings of the Turkish bath of Eger, Hungary, in order to elaborate a radon measurement protocol. Besides, measurements were also made concerning the radon and thoron short-lived decay products, gamma dose from external sources and water radon. The most accurate results for dose estimation were provided by the application of personal radon meters. Estimated annual effective doses from radon and its short-lived decay products in the old and new buildings, using 0.2 and 0.1 measured equilibrium factors, were 0.83 and 0.17 mSv, respectively. The effective dose from thoron short-lived decay products was only 5 % of these values. The respective external gamma radiation effective doses were 0.19 and 0.12 mSv y(-1). Effective dose from the consumption of tap water containing radon was 0.05 mSv y(-1), while in the case of spring water, it was 0.14 mSv y(-1). PMID:21450699

  2. Maximum likelihood estimation for cytogenetic dose-response curves

    International Nuclear Information System (INIS)

    In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa[γd + g(t, tau)d2], where t is the time and d is dose. The coefficient of the d2 term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure

  3. Dose estimates for the 1104 m APS storage ring

    International Nuclear Information System (INIS)

    The estimated dose equivalent rates outside the shielded storage ring, and the estimated annual dose equivalent to members of the public due to direct radiation and skyshine from the ring, have been recalculated. The previous estimates found in LS-84 and cited in the 1987 Conceptual Design Report of the APS required revision because of changes in the ring circumference and in the proposed location of the ring with respect to the nearest site boundary. The values assumed for the neutron quality factors were also overestimated (by a factor of 2) in the previous computation, and the correct values have been used for this estimate. The methodology used to compute dose and dose rate from the storage ring is the same as that used in LS-90. The calculations assumed 80 cm thick walls of ordinary concrete (or the shielding equivalent of this) and a roof thickness of 1 meter of ordinary concrete. The circumference of the ring was increased to 1104 m, and the closest distance to the boundary was taken as 140 m. The recalculation of the skyshine component used the same methodology as that used in LS-84

  4. Estimation of Radiation Dose for a Sitting Phantom Using PIMAL

    International Nuclear Information System (INIS)

    To assess the radiation dose in different configurations when needed (e.g., occupational exposure or public exposure in a radiologically significant event), the mathematical phantom has recently been revised to enable freely moving abilities for arms and legs. The revised phantom is called PIMAL: Phantom with Moving Arms and Legs. Additionally, a graphical user interface has been developed to assist the analyst with input preparation and output manipulation. To investigate the impact of the phantom configuration on the estimated organ doses, PIMAL has been used in a different posture than the standard vertical-upright position. In this paper, the estimated organ and effective dose values for a representative posture, the phantom in a sitting position, compared with those for the phantom in standing position, are presented

  5. Estimations of population doses and risk estimates from occupational exposures in Japan, 1978, 2

    International Nuclear Information System (INIS)

    The population doses and risks of stochastic effects from occupational exposures in Japan in 1978 were estimated on the basis of a nation-wide survey. The survey was conducted on annual collective dose equivalents by sex, age group and type of radiation work for about 82,500 workers other than the workers in nuclear power stations. The data on the workers in nuclear power stations were obtained from the offitial publication of the Japan Nuclear Safety Commission. The total number of workers except for nuclear power stations was estimated to be about 170,000 persons. Radiation works were subdivided as follows: medical works including dental; nondestructive inspectional; non-atomic energy industrial; research and educational; atomic energy industrial and nuclear power industrial. The annual collective dose equivalents were estimated to be about 6,000 man rem for medical workers, 450 man rem for non-destructive inspectional, 450 man rem for non-atomic energy industrial and 13,300 man rem for nuclear power industrial, respectively. The population doses from occupational exposures in Japan were calculated to be about 0.14 mrad person-1 year-1 for the genetically significant dose, 0.15 mrad person-1 year-1 for per Caput mean bone marrow dose, 0.14 mrad person-1 year-1 for the leukemia significant dose and 0.07 mrad person-1 year-1 for the malignancy significant dose, respectively. The risks of stochastic effects to individual and the Japanese population from occupational exposures were estimated using the data on the annual collective dose equivalent to individual and on the population doses, respectively. The total risk of population was estimated to be about 4 persons year-1. The analyses of occupational exposures such as the dose equivalent per unit electrical power generated by nuclear energy or per radiological practice to patients were carried out. (author)

  6. GARDEC, Estimation of dose-rates reduction by garden decontamination

    International Nuclear Information System (INIS)

    1 - Description of program or function: GARDEC estimates the reduction of dose rates by garden decontamination. It provides the effect of different decontamination Methods, the depth of soil to be considered, dose-rate before and after decontamination and the reduction factor. 2 - Methods: This code takes into account three Methods of decontamination : (i)digging a garden in a special way, (ii) a removal of the upper layer of soil, and (iii) covering with a shielding layer of soil. The dose-rate conversion factor is defined as the external dose-rate, in the air, at a given height above the ground from a unit concentration of a specific radionuclide in each soil layer

  7. Developing milk industry estimates for dose reconstruction projects

    International Nuclear Information System (INIS)

    One of the most important contributors to radiation doses from hanford during the 1944-1947 period was radioactive iodine. Consumption of milk from cows that ate vegetation contaminated with iodine is likely the dominant pathway of human exposure. To estimate the doses people could have received from this pathway, it is necessary to reconstruct the amount of milk consumed by people living near Hanford, the source of the milk, and the type of feed that the milk cows ate. This task is challenging because the dairy industry has undergone radical changes since the end of World War 2, and records that document the impact of these changes on the study area are scarce. Similar problems are faced by researchers on most dose reconstruction efforts. The purpose of this work is to document and evaluate the methods used on the Hanford Environmental Dose Reconstruction (HEDR) Project to reconstruct the milk industry and to present preliminary results

  8. Modeling of biological doses and mechanical effects on bone transduction

    CERN Document Server

    Rieger, Romain; Jennane, Rachid; 10.1016/j.jtbi.2011.01.003

    2012-01-01

    Shear stress, hormones like parathyroid and mineral elements like calcium mediate the amplitude of stimulus signal which affects the rate of bone remodeling. The current study investigates the theoretical effects of different metabolic doses in stimulus signal level on bone. The model was built considering the osteocyte as the sensing center mediated by coupled mechanical shear stress and some biological factors. The proposed enhanced model was developed based on previously published works dealing with different aspects of bone transduction. It describes the effects of physiological doses variations of Calcium, Parathyroid Hormone, Nitric Oxide and Prostaglandin E2 on the stimulus level sensed by osteocytes in response to applied shear stress generated by interstitial fluid flow. We retained the metabolic factors (Parathyroid Hormone, Nitric Oxide, and Prostaglandin E2) as parameters of bone cell mechanosensitivity because stimulation/inhibition of induced pathways stimulates osteogenic response in vivo. We t...

  9. Estimation of absorbed organ doses and effective dose based on body mass index in digital radiography

    International Nuclear Information System (INIS)

    With the introduction of digital radiography, patients undergoing radiographic procedures are subject to being overexposed to radiation. Therefore, it is necessary to estimate the absorbed organ dose and the effective dose, which are significant for patient health, along with body type. During chest radiographic examinations conducted in 899 patients for screening, the absorbed dose of the 13 major organs, the average whole-body dose, and two effective doses weighted by factors published in ICRP 60 and ICRP 103 were calculated on the basis of patient information such as height, weight and examination condition, including kilovolt potential, focus-skin distance and entrance surface dose (ESD), using a PC-based Monte Carlo program simulation. It was found that dose per unit ESD had a tendency to decrease with body mass index (BMI). In particular, the absorbed dose for most organs was larger at high voltages (140 kVp) than at low voltages (120 kVp, 100 kVp). In addition, the effective dose which was based on ICRP 60 and ICRP 103 also represented the same tendency in respect of BMI and tube voltage. (authors)

  10. Biological effective doses in 300 patients undergoing therapy with 177Lu-octreotate

    International Nuclear Information System (INIS)

    Full text of publication follows. Aim: fractionated therapy with 177Lu-octreotate has been reported to be an effective treatment option for patients with generalized neuroendocrine tumors. The main aim of this study was to calculate the biological effective dose (BED) to the kidneys using an individualized dosimetry protocol, and to assess differences in the number of possible treatment cycles based on BED compared to those based on absorbed dose. Methods: a total of 148 female and 152 male patients with neuroendocrine tumors with high somatostatin receptor expression (grade 3 or 4) were included. After infusion of 7.4 GBq of 177Lu-octreotate SPECT/CT images over the abdomen were acquired at 24, 96 and 168 h after infusion. Absorbed dose to kidneys was calculated based on pharmacokinetic data obtained from SPECT/CT. From this the effective half-life of 177Lu-octreotate in the kidneys was estimated, and BED was calculated using the equation described by Barone et al. (1). Results and discussion: for a single treatment cycle of 7.4 GBq, median (1:st-3:rd quartiles) BED was 5.0 Gy (3.9-6.1) in the right kidney and 4.7 Gy (3.7-5.8) in the left kidney. For the same treatment cycle, BED was 9.0% (7.1-11.3) and 8.7% (7.0-10.9) higher than absorbed dose in right and left kidneys, respectively. In patients with high absorbed doses, BED could be more than 20% higher than absorbed dose. Assuming an absorbed dose limit of 23 Gy and a BED limit of 45 Gy to the kidneys, the possible number of treatment cycles was 5.4 (4.5-6.8) based on absorbed dose while using BED increased the number of possible cycles to 9.8 (8.1-12.5). Conclusions: although biological effective dose to the kidneys is higher than absorbed dose, use of BED to estimate the number of possible treatment cycles in 177Lu-octreotate therapy may allow for more treatment cycles than the use of absorbed dose. Refs: 1) Barone, R. et al. Patient-specific dosimetry in predicting renal toxicity with (90)Y

  11. Dose inhomogeneities at various levels of biological organization

    International Nuclear Information System (INIS)

    Dose inhomogeneities in both tumor and normal tissue, inherent to the application of boron neutron capture therapy (BNCT), can be the result not only of ununiform distribution of 10B at various levels of biological organization, but also of the distribution of the thermal neutrons and of the energy depositions from more energetic neutrons and other radiations comprising the externally-applied beams. The severity of the problems resulting from such inhomogeneities, and approaches to evaluating them, are illustrated by three examples, at the macro, micro and intermediate levels

  12. Estimating the “First in human” dose – a revisit with particular emphasis on oncology drugs

    OpenAIRE

    Tam, Kin

    2013-01-01

    The initial dose selection is one of the important steps for any investigative new drug (IND) entering the first clinical study in humans. In this mini review, we will discuss the no observed adverse effect level (NOAEL) and the minimum anticipated biological effect level (MABEL) approaches for the estimation of the first in human (FIH) dose. Particular attention will be placed on the development of the FIH dose for oncology drugs.

  13. DOSGEN: 'An integrated data and dose estimation system for the cytogenetic dosimetry'

    International Nuclear Information System (INIS)

    The biological dosimetry is the only available tool for dose estimation in numerous nuclear and radiological accidents. The cytogenetic dosimetry, which uses the frequency of chromosomal aberrations in the lymphocytes of the peripheral blood as reference indicator is the most precise biological dosimetry method. The Biological Dosimetry Laboratory of the Center for Radiation Protection and Hygiene has more than 20 years of expertise carrying out the Cytogenetic Dosimetric Service; also it has implemented the requirements of ISO 19238:2004 and the ISO 17025:2005 in the laboratory management system establishment, with a complex and voluminous although necessary documentation. Furthermore, the results of mathematical procedures for dose estimations can only be achieved in a accuracy way with an adequate automation. DOSGEN allows the processing of all the information of the cases, from the patient reception up to the final report. DOSGEN has an independent module with the main mathematical operations in the Cytogenetic Dosimetry, among them all the recommended in the IAEA 405 technical report, i.e. calculating the fit coefficients of the dose response curves, checking for the adjustment of Poisson distribution of the aberration by cell, dose estimation in cases of total irradiations and the dose and the irradiated fraction estimation in cases of partial irradiations using Dolphin or Qdr method. The system records the calibration curves that are used by the laboratory. The coefficients of these curves may be calculated using the data obtained by the in vitro irradiation in the laboratory or may be introduced by the user if the coefficients were obtained out of the system. DOSGEN program was developed in Borland Delphis for Windows and Microsoft Access, with different levels of access control according to the type of user. An attractive and comprehensible environment is provided and it allows to work in network. The results can be presented by reports and correlations

  14. Estimate of dose in interventional radiology: a study of cases

    International Nuclear Information System (INIS)

    Values of absorbed dose taken by patients and professionals involved in interventional radiology can be significant mainly for the reason of these proceedings taking long time of fluoroscopy There are many methods to estimate and reduce doses of radiation in the interventional radiology, particularly because the fluoroscopy is responsible for the high dose contribution in the patient and in the professional. The aim of this work is the thermoluminescent dosimetry to estimate the dose values of the extremities of the professionals involved in the interventional radiology and the product dose-area was investigated using a Diamentor. This evaluation is particularly useful for proceedings that interest multiple parts of the organism. In this study were used thermoluminescent dosimeters (LiF:Mg, Ti - Harshaw) to estimate the dose values of the extremities of the professionals and to calibrate them. They were irradiated with X rays at 50 mGy, in Kerma in air and read in the reader Harshaw-5500. The product dose-area (D.A.P.) were obtained through the Diamentor (M2-P.T.W.) calibrated in Cgy.cm2 fixed in the exit of the X-rays tube. The patients of these study were divided in three groups: individuals submitted to proceedings of embolization, individuals submitted to cerebral and renal arteriography and individuals submitted to proceedings of Transjungular Inthahepatic Porta Systemic Stent Shunt (TIPS). The texts were always carried out by the same group: radiologist doctor), an auxiliary doctor and a nursing auxiliary. The section of interventional radiology has an Angiostar Plus Siemens equipment type arc C, in which there is trifocal Megalix X-ray tube and a intensifier of image from Sirecon 40-4 HDR/33 HDR. In this work the dose estimated values were 137.25 mSv/year for the doctors, 40.27 mSv/year for the nursing and 51.95 mSv/year for the auxiliary doctor and they are below the rule, but in this study it was not taken in consideration the emergency texts as they were

  15. Estimating effective doses to children from CT examinations

    International Nuclear Information System (INIS)

    Full text: Assessing doses to patients in diagnostic radiology is an integral part of implementing optimisation of radiation protection. Sources of normalised data are available for estimating doses to adults undergoing CT examinations, but for children this is not the case. This paper describes a simple method for estimating effective doses arising from paediatric CT examinations. First the effective dose to an adult is calculated, having anatomically matched the scanned regions of the child and the adult and also matched the irradiation conditions. A conversion factor is then applied to the adult effective dose, based on the region of the body being scanned - head, upper or lower trunk. This conversion factor is the child-to-adult ratio of the ratios of effective dose per entrance air kerma (in the absence of the patient) at the FAD. The values of these conversion factors were calculated by deriving effective dose per entrance air kerma at the FAD for new-born, 1, 5, 10, 15 and adult phantoms using four projections (AP, PA, left and right laterals) over a range of beam qualities and FADs.The program PCXMC was used for this purpose. Results to date suggest that the conversion factors to give effective doses for children undergoing CT examinations of the upper trunk are approximately 1.3, 1.2, 1.15, 1.1 and 1.05 for ages 0, 1, 5, 10 and 15 years respectively; CT of the lower trunk - 1.4, 1.3, 1.2, 1.2, 1.1; and CT of the head - 2.3, 2.0, 1.5, 1.3, 1.1. The dependence of these factors on beam quality (HVL from 4 to 10 mm Al) is less than 10%, with harder beams resulting in slightly smaller conversion factors. Dependence on FAD is also less than 10%. Major sources of uncertainties in the conversion factors include matching anatomical regions across the phantoms, and the presence of beam divergence in the z-direction when deriving the factors. The method described provides a simple means of estimating effective doses arising from paediatric CT examinations with

  16. Radiation Dose Assesment And Risk Estimation During Extracorporeal Shock Wave Lithotripsy

    International Nuclear Information System (INIS)

    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.

  17. Dose estimates for the solid waste performance assessment

    International Nuclear Information System (INIS)

    The Solid Waste Performance Assessment calculations by PNL in 1990 were redone to incorporate changes in methods and parameters since then. The ten scenarios found in their report were reduced to three, the Post-Drilling Resident, the Post-Excavation Resident, and an All Pathways Irrigator. In addition, estimates of population dose to people along the Columbia River are also included. The attached report describes the methods and parameters used in the calculations, and derives dose factors for each scenario. In addition, waste concentrations, ground water concentrations, and river water concentrations needed to reach the performance objectives of 100 mrem/yr and 500 person-rem/yr are computed. Internal dose factors from DOE-0071 were applied when computing internal dose. External dose rate factors came from the GENII Version 1.485 software package. Dose calculations were carried out on a spreadsheet. The calculations are described in detail in the report for 63 nuclides, including 5 not presently in the GENII libraries. The spreadsheet calculations were checked by comparison with GENII, as described in Appendix D

  18. I-125 seed dose estimates in heterogeneous phantom

    Energy Technology Data Exchange (ETDEWEB)

    Branco, Isabela S.L.; Antunes, Paula C.G.; Cavalieri, Tassio A.; Moura, Eduardo S.; Zeituni, Carlos A.; Yoriyaz, Helio, E-mail: isabela.slbranco@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Brachytherapy plays an important role in the healing process involving tumors in a variety of diseases. Several studies are currently conducted to examine the heterogeneity effects of different tissues and organs in brachytherapy clinical situations and a great effort has been made to incorporate new methodologies to estimate doses with greater accuracy. The objective of this study is to contribute to the assessment of heterogeneous effects on dose due to I-125 brachytherapy source in the presence of different materials with different densities and chemical compositions. The study was performed in heterogeneous phantoms using materials that simulate human tissues. Among these is quoted: breast, fat, muscle, lungs (exhaled and inhaled) and bones with different densities. Monte Carlo simulations for dose calculation in these phantoms were held and subsequently validated. The model 6711 I-125 seed was considered because it is widely used as a brachytherapy permanent implant and the one used in clinics and hospitals in Brazil. Thermoluminescent dosimeters TLD-700 (LiF: Mg, Ti) were simulated for dose assess. Several tissue configurations and positioning of I-125 sources were studied by simulations for future dose measurements. The methodology of this study so far shall be suitable for accurate dosimetric evaluation for different types of brachytherapy treatments, contributing to brachytherapy planning systems complementation allowing a better assessment of the dose actually delivered to the patient. (author)

  19. Dose estimates for the solid waste performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rittman, P.D.

    1994-08-30

    The Solid Waste Performance Assessment calculations by PNL in 1990 were redone to incorporate changes in methods and parameters since then. The ten scenarios found in their report were reduced to three, the Post-Drilling Resident, the Post-Excavation Resident, and an All Pathways Irrigator. In addition, estimates of population dose to people along the Columbia River are also included. The attached report describes the methods and parameters used in the calculations, and derives dose factors for each scenario. In addition, waste concentrations, ground water concentrations, and river water concentrations needed to reach the performance objectives of 100 mrem/yr and 500 person-rem/yr are computed. Internal dose factors from DOE-0071 were applied when computing internal dose. External dose rate factors came from the GENII Version 1.485 software package. Dose calculations were carried out on a spreadsheet. The calculations are described in detail in the report for 63 nuclides, including 5 not presently in the GENII libraries. The spreadsheet calculations were checked by comparison with GENII, as described in Appendix D.

  20. Reconstruction of biologically equivalent dose distribution on CT-image from measured physical dose distribution of therapeutic beam in water phantom

    International Nuclear Information System (INIS)

    From the standpoint of quality assurance in radiotherapy, it is very important to compare the dose distributions realized by an irradiation system with the distribution planned by a treatment planning system. To compare the two dose distributions, it is necessary to convert the dose distributions on CT images to distributions in a water phantom or convert the measured dose distributions to distributions on CT images. Especially in heavy-ion radiotherapy, it is reasonable to show the biologically equivalent dose distribution on the CT images. We developed tools for the visualization and comparison of these distributions in order to check the therapeutic beam for each patient at the National Institute of Radiological Sciences (NIRS). To estimate the distribution in a patient, the dose is derived from the measurement by mapping it on a CT-image. Fitting the depth-dose curve to the calculated SOBP curve also gives biologically equivalent dose distributions in the case of a carbon beam. Once calculated, dose distribution information can be easily handled to make a comparison with the planned distribution and display it on a grey-scale CT-image. Quantitative comparisons of dose distributions can be made with anatomical information, which also gives a verification of the irradiation system in a very straightforward way. (author)

  1. Dose estimation in interventional radiology; Estimativa de dose na radiologia intervencionista

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Nivia G.V.; Braz, Delson; Lopes, Ricardo T. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Lab. de Instrumentacao Nuclear]. E-mail: nvillela@con.ufrj.br; Vallim, Marcus A. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil); Padilha Filho, Lucas Gomes; Azevedo, Feliciano S. [Hospital Universitario Clementino Fraga Filho (HUCFF/UFRJ), Rio de Janeiro, RJ (Brazil); Barroso, Regina C. Rodrigues [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Dept. de Fisica Aplicada

    2005-07-01

    Values of absorbed dose received for patients and professionals in interventionist radiology can be significant, therefore these procedures to spend of long times of fluoroscopy. There are diverse methods of estimate and reduce values dose in interventional radiology particularly because the fluoroscopy is responsible for the high contribution of dose in the patient and the professionals. The aim of the present work is using of thermoluminescent dosimetry in order to determine dose values in extremities (fingers) of professionals involved in interventional radiology and the dose-area (DAP) was also investigated, using a Diamentor. This evaluation of DAP is important because in this procedures there are interest in multiple regions of the organism. The estimated dose values for radiology professionals in the present study were: 137,25 mSv/years for doctors, 40,27 mSv/years for nurses and 51,95 mSv/years for the auxiliary doctor. These values are lower than the norm, but this study did not take into consideration for emergency examinations, because they are specific procedures. The DAP values obtained are elevated, for patients when they are associated with a cancer risk, but they are inside the same range of values as those encountered in the literature. (author)

  2. 210Po inhalation due to smoking. A dose estimation

    International Nuclear Information System (INIS)

    Smoking is the second reason for developing lung cancer. Our goal was to determine how the amount of 210Po in the tobacco is distributed among the cigarette parts and what percentage reaches the respiratory system, calculating the effective dose. 210Po from tobacco, filter and ash samples were measured from seven Romanian cigarette brands by alpha spectrometry. The obtained average results were 13.97 ± 1.75 mBq/cigarette in the tobacco; 1.61 ± 0.25 mBq/cigarette in the filter and 3.33 ± 0.29 mBq/cigarette in the ash. The dose originating from active smoking was estimated to have an average of 8.36 ± 0.91 μSv/year, while the passive smoking dose reaching the respiratory system was 5.92 ± 0.49 μSv. (author)

  3. Development of PC version code system for radiation dose estimation

    International Nuclear Information System (INIS)

    Since a direct access from a radiation work site to a main frame computer is usually difficult, evaluation of radiation sources and/or doses are often carried out by handcalculations with less accuracy. So considering a recent remarkable progress of PC (Personal computer), we have developed an interactive code system of PC version to calculate dose equivalent values with high accuracy. It consists of a radiation source calculation code ORIGEN-2 and point kernel shielding calculation codes, QAD-CGGP2 and G33-GP2. With the present system, you can easily obtain dose equivalent values at any detector point starting from radiation source estimation. Validity of these codes have been verified individually on a main frame computer through various benchmark calculations. Thus we verified the present PC version system by comparing the PC calculations with those using a main frame computer. Excellent agreement was obtained between them. (author)

  4. Estimates of Effective Doses Among Czech Uranium Miners

    International Nuclear Information System (INIS)

    Czech uranium mining started on industrial base in the 1890s. It is estimated that total production has been 110 000 t of uranium and the uranium industry employed nearly 100 000 underground workers. Radiation doses in uranium mines include contribution form inhalation of uranium dust (long lived radionuclides), inhalation of radon and doses from external gamma radiation. The presentation is based on recent observations in Czech uranium mines. The Czech uranium mines belong to very few ones operated in Europe. The presentation is aimed at the estimation of radiation doses from long lived radionuclides, which is based on measurements of physical and chemical characteristics conducted recently in the Czech uranium mines. The main studied parameters were: size, chemical solubility in lung fluid, and amount of Rn gas emanating from uranium particles. The mean size of particles for different radionuclides in terms of AMAD was in the range 5.2-7.8 μm. Study of kinetics of dissolution of uranium collected on filters from personal dosemeters ALGADE resulted in estimated rapidly dissolved fraction (solubility class F) of 0.142 and 0.177 for U-238 and U-234, respectively. Fraction of Rn gas escaping from uranium particles was estimated by measuring the ratio of activities of radon progeny and Ra-226. These fractions, which determine how the gross long lived alpha activity is divided into separate radionuclides of the uranium series, were in the range 23% - 56% with the mean of 40%. Based on these parameters, committed effective doses from long lived radionuclides in uranium dust were calculated using conversion tables given in ICRP Publications 68 and 72 In conclusion, the results demonstrate that in present uranium mines, the annual effective doses from all three radiation components are approximately equal and separately well below 20mSv. The total annual effective dose adjusted for annual duration of 1700 hours in most workers (88%) is below 20mSv. Annual doses

  5. Development of Software for Supporting Internal Dose Estimation

    International Nuclear Information System (INIS)

    Recently developed biokinetic models of ICRP permit more realistic description of the behaviour of radionuclides in human body. This, however, has made the interpretation of bioassay data extremely difficult. Thus computer programs for implementing these models have become needed, but very few. The present work provides a personal-computer (PC) based software: MONDAL3 (Monitoring to Dose Calculation Ver.3). The models and parameter values used for computation are the respiratory tract model described in ICRP Publication 66, the biokinetic models in Publications 30, 56, 67, 69 and 71, the GI tract model in Publication 30 and the dose coefficients given in the ICRP Database of Dose Coefficients. Forty-two radionuclides are treated in this software, which cover all radionuclides in ICRP Publications 54 and 78. The subjects are both ICRP reference workers and members of the public. An AMAD of aerosol particles can be chosen among 0.1, 0.3, 1.0, 3.0, 5.0 or 10 Mum for workers. For members of the public AMAD is fixed to 1.0 mum. Three different intake modes such as acute, chronic or uneven chronic intake are considered. The present PC software supports radiation officers, whether specialists or non-specialists, to estimate readily the intake of radionuclides and resulting tissue equivalent doses and effective doses delivered for various periods from measurement results of radioactivity in a whole body or in specific organs or in excreta. (Author) 15 refs

  6. Problems in radiation absorbed dose estimation from positron emitters

    International Nuclear Information System (INIS)

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

  7. Estimation of radiation dose received by the victims in a Chinese radiation accident

    International Nuclear Information System (INIS)

    In April 1999, a radiation accident happened in Henan province, China. In this accident, A 60 Co ex-service therapy radiation source was purchased by a waster purchase company, then some persons break the lead pot and taken out the stainless steel drawer with the radiation source, then sell the drawer to another small company, and the buyer reserved the drawer in his bed room until all of his family members shoot their cookies. During the event, seven persons received overdose exposure, the dose rang is about 1.0 - 6.0Gy, especially, all of the buyer family members meet with bad radiation damage. In order to assess the accident consequences and cure the patients of the bad radiation damage, it is necessary to estimate the doses of the Victims in the accident. In the dose reconstruction of the accident victims, we adopted biologic dose method, experiment-simulating method with an anthropomorphic phantom, and theory simulating method with Monte Carlo to estimate the doses of the victims. In this paper, the frame of the accident and the Monte Carlo method in our work will be described, the main dose results of the three methods mentioned above will be reported and a comparison analysis will be presented

  8. Influence of elemental weight of human tissues estimated by ICCT software in absorbed dose calculation

    Energy Technology Data Exchange (ETDEWEB)

    Massicano, Felipe; Possani, Rafael G.; Yoriyaz, Helio [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear; Cintra, Felipe B.; Massicano, Adriana V.F., E-mail: massicano@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (DIRF/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Diretoria de Radiofarmacia

    2011-07-01

    Therapeutic use of radiopharmaceuticals in Nuclear Medicine has been well established and presented good success rates against many forms of cancer. The biologic effects of radionuclide therapy are measured via a physical quantity, the absorbed dose, which is defined as per unit mass of tissue. Therefore, it is of great important an accurate dosimetry to assess the potential effects of treatment and to confirm or contradict the treatment predictions. The most common method used to estimate the absorbed dose at organ level was developed by Medical Internal Radiation Dose (MIRD) Committee, called MIRD system. However, this method does not have adequate patient data to obtain a dose estimate accurate in therapy. In recent years, internal radionuclide radiation dosimetry system evaluated spatial dose distribution. This system is based in Monte Carlo radiation transport codes with anatomical and functional information of the patient. The high accuracy is, at least in part, due to the Monte Carlo method allows human tissues to be characterized by elemental composition and mass density. Thus, a reliable estimation of human tissues (elemental composition and mass density) must be obtained. According to Schneider, Bortfield and Schlegel, the tissue parameters (mass densities ({rho}) and elemental weights ({omega}{sub i})) can be obtained using Hounsfield units provided from Computed Tomography (CT) images. Based on this, the Nuclear Engineer Center of IPEN developed the ICCT software (Image Converter Computed Tomography). It converts CT images in tissue parameters (mass densities ({rho}) and elemental weights ({omega}{sub i}). This work intended to verify if the estimate values by software ICCT of the tissue parameter and elemental weights ({omega}{sub i}) are plausible to estimate the absorbed dose with reasonable accuracy. (author)

  9. Radiation Dose Estimation Using Realistic Postures with PIMAL

    International Nuclear Information System (INIS)

    For correct radiation dose assessment, it is important to take the posture into account. A computational phantom with moving arms and legs was previously developed to address this need. Further, an accompanying graphical user interface (GUI), called PIMAL, was developed to enable dose estimation using realistic postures in a user-friendly manner such that the analyst's time could be substantially reduced. The importance of the posture for correct dose estimation has been demonstrated with a few case studies in earlier analyses. The previous version of PIMAL was somewhat limited in its features (i.e., it contained only a hermaphrodite phantom model and allowed only isotropic source definition). Currently GUI is being further enhanced by incorporating additional phantom models, improving the features, and increasing the user friendliness in general. This paper describes recent updates to the PIMAL software. In this summary recent updates to the PIMAL software, which aims to perform radiation transport simulations for phantom models in realistic postures in a user-friendly manner, are described. In future work additional phantom models, including hybrid phantom models, will be incorporated. In addition to further enhancements, a library of input files for the case studies that have been analyzed to date will be included in the PIMAL.

  10. Estimates of dose equivalent rates from natural background radiation

    International Nuclear Information System (INIS)

    Environmental monitoring in Khartoum is being conducted using thermoluminescent dosimetry.The purpose of the study is to estimate dose-equivalent rates from natural background radiation.TL phosphorus LiF.Mg, Cu, P and CaSO4:Mn were used to measure the exposure over land for natural background radiation of terrestrial origin plus cosmic radiation and at position over the Blue Nile to account for natural background radiation of extraterrestrial origin (cosmic rays).The associated dose-equivalent rates have been determined.It was found that the dose-equivalent rates from cosmic radiation obtained through this work using the two types of the TLD phosphorus GR-200 A and CaSO4 are 0.295 mSv per year and 0.265 mSv per year, respectively.While the dose-equivalent rates from total natural background radiation obtained through this work are 0.395 mSv per year using GR-200 A and CaSO4 phosphorus, respectively. (Author)

  11. In-flight measured and predicted ambient dose equivalent and latitude differences on effective dose estimates

    International Nuclear Information System (INIS)

    The results from 2 years (2001-2002) of experimental measurements of in-board radiation doses received at Iberia commercial flights are presented. The routes studied cover the most significant destinations and provide a good estimate of the route doses as required by the new Spanish regulations on air crew radiation protection. Details on the experimental procedures and calibration methods are given. The experimental measurements from the different instruments (Tissue Equivalent Proportional Counter and the combination of a high pressure ion chamber and a high-energy neutron compensated rem-counter) and their comparison with the predictions from some route-dose codes (CARI-6, EPCARD 3.2) are discussed. In contrast with the already published data, which are mainly focused on North latitudes over parallel 50, many of the data presented in this work have been obtained for routes from Spain to Central and South America. (authors)

  12. Estimation of mean glandular dose for mammography of augmented breasts

    Science.gov (United States)

    Beckett, J. R.; Kotre, C. J.

    2000-11-01

    The standard quantity used to relate breast surface exposure to radiation risk is the mean dose received by the radiation sensitive tissue contained within the female breast, the mean glandular dose (MGD). At present, little is known about the MGD received by women with breast implants as there is no technique available to facilitate its calculation. The present work has involved modification of the conventional method for MGD estimation to make it applicable to women with augmented breasts. The technique was used to calculate MGDs for a cohort of 80 women with breast implants, which were compared with similar data calculated for a total of 1258 non-augmented women. Little difference was found in median MGD at low compressed breast thickness. At high breast thickness, however, the MGDs received by women with augmented breasts were found to be considerably lower than those relating to their non-augmented counterparts.

  13. Influence of TLD position on the estimate of fetal dose

    International Nuclear Information System (INIS)

    This report examines the adequacy of the practice of using a single dosimeter worn at the front of the body as an estimate of the dose received by nuclear medicine technologies. In order to investigate this, a group of approximately 50 technologists at 9 different hospitals were double-badged, i.e. provided with front and back dosimeters, and the ratio of front to back dose computed. Both aggregate data and hospital-specific data are presented and accompanied by several forms of statistical analysis. Apparent trends and possible explanations are discussed. Recommendations are provided for additional studies relating to the badging of nuclear medicine technologists. (author). 125 refs., 15 tabs., 13 figs

  14. Estimation of mean glandular dose for mammography of augmented breasts

    International Nuclear Information System (INIS)

    The standard quantity used to relate breast surface exposure to radiation risk is the mean dose received by the radiation sensitive tissue contained within the female breast, the mean glandular dose (MGD). At present, little is known about the MGD received by women with breast implants as there is no technique available to facilitate its calculation. The present work has involved modification of the conventional method for MGD estimation to make it applicable to women with augmented breasts. The technique was used to calculate MGDs for a cohort of 80 women with breast implants, which were compared with similar data calculated for a total of 1258 non-augmented women. Little difference was found in median MGD at low compressed breast thickness. At high breast thickness, however, the MGDs received by women with augmented breasts were found to be considerably lower than those relating to their non-augmented counterparts. (author)

  15. Measuring radon concentrations and estimating dose in tourist caves.

    Science.gov (United States)

    Martín Sánchez, A; de la Torre Pérez, J; Ruano Sánchez, A B; Naranjo Correa, F L

    2015-11-01

    Caves and mines are considered to be places of especial risk of exposure to (222)Rn. This is particularly important for guides and workers, but also for visitors. In the Extremadura region (Spain), there are two cave systems in which there are workers carrying out their normal everyday tasks. In one, visits have been reduced to maintain the conditions of temperature and humidity. The other comprises several caves frequently visited by school groups. The caves were radiologically characterised in order to estimate the dose received by workers or possible hazards for visitors. PMID:25948834

  16. Measuring radon concentrations and estimating dose in tourist caves

    International Nuclear Information System (INIS)

    Caves and mines are considered to be places of especial risk of exposure to 222Rn. This is particularly important for guides and workers, but also for visitors. In the Extremadura region (Spain), there are two cave systems in which there are workers carrying out their normal everyday tasks. In one, visits have been reduced to maintain the conditions of temperature and humidity. The other comprises several caves frequently visited by school groups. The caves were radiologically characterised in order to estimate the dose received by workers or possible hazards for visitors. (authors)

  17. Radiopharmaceuticals introduction to drug evaluation and dose estimation

    CERN Document Server

    Williams, Lawerence E

    2010-01-01

    Nanoengineering, energized by the desire to find specific targeting agents, is leading to dramatic acceleration in novel drug design. However, in this flurry of activity, some issues may be overlooked. This is especially true in the area of determining dosage and evaluating the effects of multiple agents designed to target more than one site of metastasis. Offering the unique perspective of a medical physicist who has worked directly with cancer patients for over three decades, Radiopharmaceuticals: Introduction to Drug Evaluation and Dose Estimation starts by exploring the recent history and

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

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

    International Nuclear Information System (INIS)

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

  20. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    Science.gov (United States)

    Wang, Chu

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Loewe, W.E.

    1986-12-01

    Four decades after the actual events, quantitative characterization of the radiation fields at Hiroshima and Nagasaki continues to be sought, with high accuracy a goal justified by the unique contribution to radiation protection standards that is represented by the medical records of exposed survivors. The most recent effort is distinguished by its reliance on computer modeling and concomitant detail, and by its decentralized direction, both internationally and internally to the US and Japan, with resultant ongoing peer review and wide scope of inquiry. A new system for individual dose estimation has been agreed upon, and its scientific basis has been elaborated in the literature as well as in a comprehensive treatise to be published in the Spring of 1987. In perspective, this new system appears to be an unusually successful achievement that offers the expectation of reliable estimates with the desired accuracy. Some aspects leading to this expectation, along with a caveat, are discussed here. 4 refs., 8 figs., 3 tabs.

  2. 324 Building life cycle dose estimates for planned work

    International Nuclear Information System (INIS)

    This report describes a tool for use by organizational management teams to plan, manage, and oversee personnel exposures within their organizations. The report encompasses personnel radiation exposures received from activities associated with the B-Cell Cleanout Project, Surveillance and Maintenance Project, the Mk-42 Project, and other minor activities. It is designed to provide verifiable Radiological Performance Reports. The primary area workers receive radiation exposure is the Radiochemical Engineering Complex airlock. Entry to the airlock is necessary for maintenance of cranes and other equipment, and to set up the rail system used to move large pieces of equipment and shipping casks into and out of the airlock. Transfers of equipment and materials from the hot cells in the complex to the airlock are required to allow dose profiles of waste containers, shuffling of waste containers to allow grouting activities to go on, and to allow maintenance of in-cell cranes. Both DOE and the Pacific Northwest Laboratory (PNL) are currently investing in state-of-the-art decontamination equipment. Challenging goals for exposure reduction were established for several broad areas of activity. Exposure estimates and goals developed from these scheduled activities will be compared against actual exposures for scheduled and unscheduled activities that contributed to exposures received by personnel throughout the year. Included in this report are life cycle exposure estimates by calendar year for the B-Cell Cleanout project, a three-year estimate of exposures associated with Surveillance and Maintenance, and known activities for Calendar Year (CY) 1995 associated with several smaller projects. These reports are intended to provide a foundation for future dose estimates, by year, requiring updating as exposure conditions change or new avenues of approach to performing work are developed

  3. Biological dosimetry in radiological protection: dose response curves elaboration for 60Co and 137Cs

    International Nuclear Information System (INIS)

    Ionizing radiation sources for pacific uses are being extensively utilized by modern society and the applications of these sources have raised the probability of the occurrence of accidents. The accidental exposition to radiation creates a necessity of the development of methods to evaluate dose quantity. This data could be obtained by the measurement of damage caused by radiation in the exposed person. The radiation dose can be estimated in exposed persons through physical methods (physical dosimetry) but the biological methods can't be dispensed, and among them, the cytogenetic one that makes use of chromosome aberrations (dicentric and centric ring) formed in peripheral blood lymphocytes (PBL) exposed to ionizing radiation. This method correlates the frequency of radioinduced aberrations with the estimated absorbed dose, as in vitro as in vivo, which is called cytogenetic dosimetry. By the introduction of improved new techniques in culture, in the interpretation of aberrations in the different analysers of slides and by the adoption of different statistical programs to analyse the data, significant differences are observed among laboratories in dose-response curves (calibration curves). The estimation of absorbed dose utilizing other laboratory calibration curves may introduce some uncertainties, so the International Atomic Energy Agency (IAEA) advises that each laboratory elaborates your own dose-response curve for cytogenetic dosimetry. The results were obtained from peripheral blood lymphocytes of the healthy and no-smoking donors exposed to 60Co and 137Cs radiation, with dose rate of 5 cGy.min.-1. Six points of dose were determined 20,50,100,200,300,400 cGy and the control not irradiated. The analysed aberrations were of chromosomic type, dicentric and centric ring. The dose response curve for dicentrics were obtained by frequencies weighted in liner-quadratic mathematic model and the equation resulted were for 60Co: Y = (3 46 +- 2.14)10-4 cGy-1 + (3.45 +- 0

  4. Calibration factor for estimating personal dose equivalent with imaging plates

    International Nuclear Information System (INIS)

    A personal imaging plate (IP) dosimeter is in the process of being developed for neutron fields using the BaFBr:Eu2+ phosphor. A configuration incorporating a polyethylene radiator placed before the IP detector is used to produce protons via (n,p) elastic scattering. For a dosimeter sensitive to thermal neutrons, a Nylon plate (100μm thick) is placed between the polyethylene (1.2mm thick) radiator and the IP (130μm thick sensitive layer) detector to produce protons via the 14N(n,p)14C reaction. Dosimeters having these configurations have been exposed to neutrons from 241Am-Be and 252Cf sources at the Institute for Radioprotection and Nuclear Safety of Cadarache at angles of 0 deg. (normal incidence), 30 deg. and 60 deg. and several dose equivalents. The personal dose equivalent response in terms of Hp(10) is evaluated from the net measured photostimulated luminescence densities (PSLmm-2). The calibration factor obtained for estimating the personal dose equivalent with this dosimeter is 9.20x10-5mSvPSL-1mm2 for 241Am-Be and 13.07x10-5mSvPSL-1mm2 for 252Cf

  5. Estimates of dose from radon daughters in UK mines

    International Nuclear Information System (INIS)

    Radon concentrations in many non-coal and private sector coal mines were measured with passive radon monitors in a cooperative exercise between the National Radiological Protection Board and the Mines Inspectorate of the Health and Safety Executive. Radon daughter concentrations were measured in deep coal mines by British Coal. The results presented show that, in the mines surveyed, statutory regulations require supervision or control of doses in about one-third of the non-coal mines and almost one-tenth of the private sector coal mines and in virtually no deep coal mines. Average annual doses in the three groups of mines are estimated at 14 mSv, 5 mSv and 0.95 mSv respectively; the average for all UK miners is 1.3 mSv. Progress with the supervision and control of doses is described, and information presented on large reductions in concentrations achieved by the straightforward application of good ventilation principles. (Author)

  6. Biological dose representation for carbon-ion radiotherapy of unconventional fractionation

    OpenAIRE

    Kanematsu, Nobuyuki; Inaniwa, Taku

    2016-01-01

    In carbon-ion radiotherapy, single-beam delivery each day in alternate directions has been commonly practiced for operational efficiency, taking advantage of the Bragg peak and the relative biological effectiveness (RBE) for uniform dose conformation to a tumor. The treatment plans are usually evaluated with total RBE-weighted dose, which is however deficient in relevance to the biological effect in the linear-quadratic model due to its quadratic-dose term, or the dose-fractionation effect. I...

  7. Estimated doses from decommissioning activities at commercial nuclear power stations

    International Nuclear Information System (INIS)

    This paper reviews generic population dose estimates for decommissioning reference boiling water reactors (BWRs) and pressurized water reactors (PWRs) and provides extrapolated estimates of the total collective dose resulting from decommissioning commercial nuclear reactors operated in the United States. Decontamination and decommissioning of retired nuclear power reactors is a necessary part of the nuclear fuel cycle. During decommissioning of large facilities, radioactivity will be encountered in activated reactor components and in contaminated piping, equipment, and building surfaces. The US Nuclear Regulatory Commission (NRC) sponsored a series of studies to evaluate the technology, safety, and costs of decommissioning a variety of nuclear fuel cycle facilities. The NRC adopted the following standardized definitions concerning decommissioning: (1) decommissioning: the measures taken at the end of a facility's operating lifetime to ensure the protection of the public from any residual radioactivity or other hazards present in the facility; (2) DECON: immediate decontamination leading to the release of the facility for unrestricted use; (3) SAFSTOR: safe storage plus deferred decontamination leading to release of the facility for unrestricted use; and (4) ENTOMB: entombment plus decay leading to release of the facility for unrestricted use. In the NRC studies, the most likely decommissioning alternative for most facilities was assumed to be DECON or SAFSTOR

  8. Parameter estimation in systems biology models using spline approximation

    OpenAIRE

    Yeung Lam F; Zhan Choujun

    2011-01-01

    Abstract Background Mathematical models for revealing the dynamics and interactions properties of biological systems play an important role in computational systems biology. The inference of model parameter values from time-course data can be considered as a "reverse engineering" process and is still one of the most challenging tasks. Many parameter estimation methods have been developed but none of these methods is effective for all cases and can overwhelm all other approaches. Instead, vari...

  9. Influence of radioactive contaminants on absorbed dose estimates for radiopharmaceuticals

    International Nuclear Information System (INIS)

    Several popular radiopharmaceutical products contain low levels of radioactive contaminants. These contaminants increase the radiation absorbed dose to the patient without any increased benefit and, in some cases, with a decrease in image quality. The importance of a contaminant to the radiation dosimetry picture is a function of 1) the contaminant level, 2) the physical half-life of the contaminant, 3) the organ uptake and the biological half-time of the contaminant in the various body systems, and 4) the decay mode, energy, etc. of the contaminant. The general influence of these parameters is discussed in this paper; families of curves are included that reflect the changing importance of contaminant dosimetry with respect to the primary radionuclide as a function of these variables. Several specific examples are also given of currently used radiopharmaceutical products which can contain radioactive contaminants (I-123, In-111, Tl-201, Ir-191m, Rb-82, Au-195m). 7 references, 8 figures, 4 tables

  10. Comparison in the determination of absorbed dose by biological and physical methods to patients in treatment of cardiac intervention

    International Nuclear Information System (INIS)

    The use of less invasive procedures, lower risk and quick recovery as cardiac intervention have proven to be an efficient alternative to reestablish the correct bloodstream of the patient. In this case the patient is subjected to values of absorbed dose above to which is subjected in a study with X-rays for medical diagnosis, and this can cause radiation injuries to the skin. The target organ, in this case can be exposed to doses of 2 Gy above. Different methods to estimate the dose were use, physical by Radiochromic film, as biological by dicentric analysis. Both methods provided additional information demonstrating thus the risk in the target organ and the patient. The most reliable biological indicator of exposure to ionizing radiation is the study of chromosomal aberrations, specifically dicentric in human lymphocytes. This test allowed establishing the exposure dose depending of the damage. (Author)

  11. Development of Two-Dosemeter Algorithm for Better Estimation of Effective Dose Equivalent and Effective Dose

    International Nuclear Information System (INIS)

    An optimal algorithm, which suitably combines two dosemeter readings, one dosemeter on the chest and the other on the back, for better estimation of effective dose equivalent (HE) and effective dose (E), was developed by utilising hundreds of broad parallel photon beam irradiation geometries. The developed algorithm, weighting front (chest) and back dosemeter readings by 0.58 and 0.42, respectively, was found to be superior to other currently available algorithms, neither underestimating HE or E by more than 14%, nor overestimating by more than a few tens of a per cent for a broad range of frontal and dorsal incident beams. Like other algorithms, however, this algorithm tends to overestimate HE and E significantly for the lateral, overhead and underfoot beam directions. This study also suggests that this overestimation problem significantly decreases when one uses typical commercial dosemeters instead of isotropic-responding dosemeters. (author)

  12. Dynamic noise, chaos and parameter estimation in population biology

    OpenAIRE

    Stollenwerk, N.; Aguiar, M; Ballesteros, S.; Boto, J.; Kooi, B. W.; Mateus, L.

    2012-01-01

    We revisit the parameter estimation framework for population biological dynamical systems, and apply it to calibrate various models in epidemiology with empirical time series, namely influenza and dengue fever. When it comes to more complex models such as multi-strain dynamics to describe the virus–host interaction in dengue fever, even the most recently developed parameter estimation techniques, such as maximum likelihood iterated filtering, reach their computational limits. However, the fir...

  13. Estimated UV doses to psoriasis patients during climate therapy at Gran Canaria in March 2006

    Directory of Open Access Journals (Sweden)

    L. T. N. Nilsen

    2008-01-01

    Full Text Available Psoriasis is a chronic inflammatory disease involving about 2–3% of the Norwegian population. Sun exposure has a positive effect on most psoriasis lesions, but ultraviolet (UV radiation also causes a direct DNA damage in the skin cells and comprises a carcinogenic potential. UV exposure on the skin causes a local as well as a systemic immune suppressive effect, but the relation between sun exposure and these biological effects is not well known. In March 2006 a study was carried out to investigate possible therapeutic outcome mechanisms in 20 psoriasis patients receiving climate therapy at Gran Canaria. This paper presents estimates of their individual skin UV-doses based on UV measurements and the patients' diaries with information on time spent in the sun.

    On the first day of exposure the patients received on average 5.1 Standard Erythema Doses (SED: median=4.0 SED, range 2.6–10.3 SED estimated to the skin. During the 15 days study they received 165.8 SED (range 104.3–210.1 SED. The reduction in PASI score was 72.8% on average, but there was no obvious relation between the improvement and the UV dose. The UV doses were higher than those found from climate therapy studies at other locations. It seems beneficial to use more strict exposure schedules that consider the available UV irradiance, depending on time of the day, time of the year and weather conditions.

  14. An estimate of cosmic dose component around Kudankulam site

    International Nuclear Information System (INIS)

    Natural ionizing radiation pervades the whole environment and enters human lives in a wide variety of ways. It arises from natural processes such as the decay of terrestrially deposited radionuclides in the earth, and artificial processes like the use of X-rays in medicine. Thus, radiation can be classified as natural and artificial depending on its origin. Natural sources include cosmic rays, terrestrial gamma radiation, radon and its decay products in air and various radio nuclides found naturally in food and drink. Cosmic rays reach the earth from outer space. Artificial sources include medical X-rays, therapeutic use of radioisotopes, fallout from past weapon tests, discharges from nuclear industry, industrial gamma rays and use of radioisotopes in consumer products. This paper attempts to estimate the natural cosmic dose component around Kudankulam Nuclear Power Plant site in the south eastern coast of India. (author)

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

  16. Use of doubling doses for the estimation of genetic risks

    International Nuclear Information System (INIS)

    Doubling dose estimates derived from radiation experiments in mice are proving of great value for the assessment of genetic hazards to man from extra radiation exposure because they allow the latest information on mutation frequencies and the incidence of genetic disease in man to be used in the assessment process. The similarity in spectra of 'spontaneous' and induced mutations increases coincidence in the validity of this approach. Data on rates of induction of dominant and recessive mutations, translocations and X-chromosome loss are used to derive doubling doses for chronic exposures to both low and high-LET radiations. Values for γ and X-rays, derived from both male and female germ-cells, fall inside a fairly small range and it is felt that the use of an overall figure of 100 rads is justifiable for protection purposes. Values for neutrons and α-particles, obtained from male germ-cells, varied according to neutron energy etc. but clustered around a value of 5 rads for fission neutrons

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

    Science.gov (United States)

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

    2015-09-28

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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 μn and adaptive μa radiosensitivities. The significances of μn are determined by host (inner) factors; and the significances of μa, 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

  20. Concept of dose estimation system based on the analysis of environment transfer

    International Nuclear Information System (INIS)

    A personal computer program system (IDES) was developed in the past by authors for estimation of internal radiation dose for Japanese people. Since the metabolism and environment models could be described as transformation determinants, the above authors' system was found to be expanded to the calculation of exposure dose (ERMA) by simulation of radionuclide transfer model in the environment. The model was the ICRP one where radionuclides released in the environment were finally incorporated in the human body after dilution and/or concentration in the complicated physical, chemical and biological systems which were depicted as the respective compartments. At present, the program is made up as a system provided with Xwindow, Web-browser and e-mail user-interphase. (K.H.)

  1. Estimation of radiation doses from 137Cs to frogs in a wetland ecosystem

    International Nuclear Information System (INIS)

    Currently, there is no established methodology to estimate radiation doses to non-human biota. Therefore, in this study, various dose models were used to estimate radiation doses to moor frogs (Rana arvalis) in a wetland ecosystem contaminated with 137Cs. External dose estimations were based on activity concentrations of 137Cs in soil and water, considering changes in habitat over a life-cycle. Internal doses were calculated from the activity concentrations of 137Cs measured in moor frogs. Depending on the dose model used, the results varied substantially. External dose rates ranged from 21 to 160 mGy/y, and internal dose rates varied between 1 and 14 mGy/y. Maximum total dose rates to frogs were below the expected safe level for terrestrial populations, but close to the suggested critical dose rate for amphibians. The results show that realistic assumptions in dose models are particularly important at high levels of contamination

  2. Radiobiological impact of dose calculation algorithms on biologically optimized IMRT lung stereotactic body radiation therapy plans

    OpenAIRE

    Liang, X.; Penagaricano, J.; Zheng, D.; Morrill, S.; Zhang, X; Corry, P.; Griffin, R. J.; Han, E. Y.; Hardee, M.; Ratanatharathom, V.

    2016-01-01

    Background The aim of this study is to evaluate the radiobiological impact of Acuros XB (AXB) vs. Anisotropic Analytic Algorithm (AAA) dose calculation algorithms in combined dose-volume and biological optimized IMRT plans of SBRT treatments for non-small-cell lung cancer (NSCLC) patients. Methods Twenty eight patients with NSCLC previously treated SBRT were re-planned using Varian Eclipse (V11) with combined dose-volume and biological optimization IMRT sliding window technique. The total dos...

  3. Dose-Volume Histogram Prediction using KernelDensity Estimation

    OpenAIRE

    SKARPMAN MUNTER, JOHANNA

    2014-01-01

    Dose plans developed for stereotactic radiosurgery are assessed by studying so called Dose-Volume Histograms. Since it is hard to compare an individual dose plan with doseplans created for other patients, much experience and knowledge is lost. This thesis therefore investigates a machine learning approach to predicting such Dose-Volume Histograms for a new patient, by learning from previous dose plans.The training set is chosen based on similarity in terms of tumour size. The signed distances...

  4. Standards in biological dosimetry: A requirement to perform an appropriate dose assessment.

    Science.gov (United States)

    Voisin, Philippe

    2015-11-01

    Every year, many countries perform a significant number of investigations based on biological radiation dose assessment to check suspected or true overexposure by irradiation of radiation workers and individuals of the general population. The scoring of dicentrics in peripheral blood lymphocytes has gradually become the "gold standard" for the biodosimetry-based assessment of accidental situations. Nevertheless, other "classical" biodosimetric methods such as micronuclei, prematurely condensed chromosomes (PCC) and FISH translocations are relevant in some exposure situations, also for surveillance of groups of populations at risk. Historical international intercomparison studies have shown discrepancies among dose-effect curves used to estimate doses from blood samples irradiated between 0 and 4Gy. Recent experimental work performed by the biological dosimetry laboratory of the French Institute for Radiation Protection and Nuclear Safety (IRSN) has shown the impact of some blood harvesting parameters on the mitotic index, and consequently on the quality of dose assessment. Therefore, it was relevant to define the best Quality Assurance (QA) and Quality Control (QC) criteria to harmonize protocols among biodosimetry laboratories. Complementary with several editions of an IAEA technical manual, ISO standards were written with the view of considering the most used chromosome aberrations assays: dicentrics and micronuclei. An important feature of these standards is to address the organization of population triage and laboratories networking that would be required in case of a large nuclear event or malicious act involving radioactive material. These ISO standards are relevant and helpful to implement a coordinated response of several biodosimetry networks in Europe, Japan, Canada, and to support European programs such as MULTIBIODOSE and RENEB. A new important ISO standard on the use of FISH translocations in retrospective dosimetry is now being drafted. PMID:26520381

  5. Biologically effective uniform dose (D) for specification, report and comparison of dose response relations and treatment plans

    International Nuclear Information System (INIS)

    Developments in radiation therapy planning have improved the information about the three-dimensional dose distribution in the patient. Isodose graphs, dose volume histograms and most recently radiobiological models can be used to evaluate the dose distribution delivered to the irradiated organs and volumes of interest. The concept of a biologically effective uniform dose (D) assumes that any two dose distributions are equivalent if they cause the same probability for tumour control or normal tissue complication. In the present paper the D concept both for tumours and normal tissues is presented, making use of the fact that probabilities averaged over both dose distribution and organ radiosensitivity are more relevant to the clinical outcome than the expected number of surviving clonogens or functional subunits. D can be calculated in complex target volumes or organs at risk either from the 3D dose matrix or from the corresponding dose volume histograms of the dose plan. The value of the D concept is demonstrated by applying it to two treatment plans of a cervix cancer. Comparison is made of the D concept with the effective dose (Deff) and equivalent uniform dose (EUD) that have been suggested in the past. The value of the concept for complex targets and fractionation schedules is also pointed out. (author)

  6. CY 1995 radiation dose reconciliation report and resulting CY 1996 dose estimate for the 324 nuclear facility

    International Nuclear Information System (INIS)

    In this report, the dose estimate for CY 1995 is reconciled by month wih actual doses received. Results of the reconciliation were used to revise estimates of worker dose for CY 1996. Resulting dose estimate for the facility is also included. Support for two major programs (B-Cell Cleanout and Surveillance and Maintenance) accounts for most of the exposure received by workers in the faility. Most of the expousre received by workers comes from work in the Radiochemical Engineering Complex airlock. In spite of schedule and work scope changes during CY 1995, dose estimates were close to actual exposures received. A number of ALARA measures were taken throughout the year; exposure reduction due to those was 20.6 Man-Rem, a 28% reduction from the CY 1995 estimate. Baseline estimates for various tasks in the facility were used to compile the CY 1996 dose estimate of 45.4 Man-Rem; facility goal for CY 1996 is to reduce worker dose by 20%, to 36.3 Man-Rem

  7. CY 1995 radiation dose reconciliation report and resulting CY 1996 dose estimate for the 324 nuclear facility

    Energy Technology Data Exchange (ETDEWEB)

    Landsman, S.D.; Thornhill, R.E.; Peterson, C.A.

    1996-04-01

    In this report, the dose estimate for CY 1995 is reconciled by month wih actual doses received. Results of the reconciliation were used to revise estimates of worker dose for CY 1996. Resulting dose estimate for the facility is also included. Support for two major programs (B-Cell Cleanout and Surveillance and Maintenance) accounts for most of the exposure received by workers in the faility. Most of the expousre received by workers comes from work in the Radiochemical Engineering Complex airlock. In spite of schedule and work scope changes during CY 1995, dose estimates were close to actual exposures received. A number of ALARA measures were taken throughout the year; exposure reduction due to those was 20.6 Man-Rem, a 28% reduction from the CY 1995 estimate. Baseline estimates for various tasks in the facility were used to compile the CY 1996 dose estimate of 45.4 Man-Rem; facility goal for CY 1996 is to reduce worker dose by 20%, to 36.3 Man-Rem.

  8. Biological effects in lymphocytes irradiated with 99mTc: determination of the curve dose-response

    International Nuclear Information System (INIS)

    Biological dosimetry estimates the absorbed dose taking into account changes in biological parameters. The most used biological indicator of an exposition to ionizing radiation is the quantification of chromosomal aberrations of lymphocytes from irradiated individuals. The curves of dose versus induced biological effects, obtained through bionalyses, are used in used in retrospective evaluations of the dose, mainly in the case of accidents. In this research, a simple model for electrons and photons transports was idealized to simulate the irradiation of lymphocytes with 99m Tc, representing a system used for irradiation of blood cells. The objective of the work was to establish a curve of dose versus frequencies of chromosomal aberrations in lymphocytes of human blood. For the irradiation of blood samples micro spheres of human serum of albumin (HSAM) market with 99m Tc were used, allowing the irradiation of blood with different administered activities of 99m Tc, making possible the study the cytogenetical effects as a function of such activities. The conditions of irradiation in vivo using HSAM spheres marked with 99m Tc were simulated with MCNP 4C (Monte Carlo N-Particle) code to obtain the dose-response curve. Soft tissue composition was employed to simulate blood tissue and the analyses of the curve of dose versus biological effect showed a linear quadratic response of the unstable chromosomal aberrations. As a result, the response of dose versus chromosomal aberrations of blood irradiation with 99m Tc was best fitted by the curve Y=(8,99 ±2,06) x 1--4 + (1,24 ±0,62) x 10-2 D + (5,67 ± 0,64) x 10-2 D2. (author)

  9. Isoeffective dose: a concept for biological weighting of absorbed dose in proton and heavier-ion therapies

    CERN Document Server

    Wambersie, A; Menzel, H G; Gahbauer, R; DeLuca, P M; Hendry, J H; Jones, D T L

    2011-01-01

    When reporting radiation therapy procedures, International Commission on Radiation Units and Measurements (ICRU) recommends specifying absorbed dose at/in all clinically relevant points and/or volumes. In addition, treatment conditions should be reported as completely as possible in order to allow full understanding and interpretation of the treatment prescription. However, the clinical outcome does not only depend on absorbed dose but also on a number of other factors such as dose per fraction, overall treatment time and radiation quality radiation biology effectiveness (RBE). Therefore, weighting factors have to be applied when different types of treatments are to be compared or to be combined. This had led to the concept of `isoeffective absorbed dose', introduced by ICRU and International Atomic Energy Agency (IAEA). The isoeffective dose D(IsoE) is the dose of a treatment carried out under reference conditions producing the same clinical effects on the target volume as those of the actual treatment. It i...

  10. Size-specific dose estimate (SSDE) provides a simple method to calculate organ dose for pediatric CT examinations

    International Nuclear Information System (INIS)

    Purpose: To investigate the correlation of size-specific dose estimate (SSDE) with absorbed organ dose, and to develop a simple methodology for estimating patient organ dose in a pediatric population (5–55 kg). Methods: Four physical anthropomorphic phantoms representing a range of pediatric body habitus were scanned with metal oxide semiconductor field effect transistor (MOSFET) dosimeters placed at 23 organ locations to determine absolute organ dose. Phantom absolute organ dose was divided by phantom SSDE to determine correlation between organ dose and SSDE. Organ dose correlation factors (CFSSDEorgan) were then multiplied by patient-specific SSDE to estimate patient organ dose. The CFSSDEorgan were used to retrospectively estimate individual organ doses from 352 chest and 241 abdominopelvic pediatric CT examinations, where mean patient weight was 22 kg ± 15 (range 5–55 kg), and mean patient age was 6 yrs ± 5 (range 4 months to 23 yrs). Patient organ dose estimates were compared to published pediatric Monte Carlo study results. Results: Phantom effective diameters were matched with patient population effective diameters to within 4 cm; thus, showing appropriate scalability of the phantoms across the entire pediatric population in this study. IndividualCFSSDEorgan were determined for a total of 23 organs in the chest and abdominopelvic region across nine weight subcategories. For organs fully covered by the scan volume, correlation in the chest (average 1.1; range 0.7–1.4) and abdominopelvic region (average 0.9; range 0.7–1.3) was near unity. For organ/tissue that extended beyond the scan volume (i.e., skin, bone marrow, and bone surface), correlation was determined to be poor (average 0.3; range: 0.1–0.4) for both the chest and abdominopelvic regions, respectively. A means to estimate patient organ dose was demonstrated. Calculated patient organ dose, using patient SSDE and CFSSDEorgan, was compared to previously published pediatric patient doses that

  11. Radioactivity levels of basic foodstuffs and dose estimates in Sudan

    International Nuclear Information System (INIS)

    In this work a comprehensive study was carried out for the determination of different radionuclides activities in foodstuff consumed and evaluation of dose levels in different food stuffs were collected from eight States in Sudan (cereals, vegetables, meat, fruits, milk, and fermented milk, baby milk, cans, spices, additives, others). The concentrations of different radionuclides in the food samples were determined by gamma spectrometry using an HPGe detector. Radionuclides observed include: Bi-212, Bi-214, Cs-134, Cs-137, K-40, Pb-212, Pb-214, Ra-224, Ra-226, Th-228, Ac-228, TI-208, Th-232, and U-238. The activity concentration of these radionuclides were found in the following ranges: 0.51 - 19.42 Bq/Kg, 0.47 - 12.13 Bq/kg, 0.5 - 1.29 Bq/kg, 0.001 - 3.41 Bq/kg, 19.25 -2521.82 Bq/kg, 0.08 - 6.84 Bq/kg, 0.02 - 6.87 Bq/kg, 6.08 - 32.02 Bq/kg, 0.03 - 21. 53 Bq/kg, 0.92 - 26.77 Bq/kg, 0.91 - 1200 Bq/kg, 0.14 - 2.58 Bq/Kg, 0.03 - 9.65 Bq/kg, 0.03 - 9.65 Bq/kg and 0.82 - 5.27 Bq/kg respectively. High concentrations were typically found in portulaca, the lowest concentrations were found in barley and bread additives. The annual effective dose due to the different foodstuff estimated was found to be 2.78±0.44 mSv/y and 1.18±mSv/y for age categories 7-12 y and> 17y respectively. (Author)

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

    International Nuclear Information System (INIS)

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

  13. Estimation of the fetal dose by dose measurement during an irradiation of a parotid tumor; Estimation de la dose foetale par mesure de dose lors d'une irradiation d'une tumeur de la parotide

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, V.; Graff-Cailleaud, P.; Peiffert, D. [Centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Noel, A. [Institut National Polytechnique de Lorraine, CRAN CNRS UMR-7039, 54 - Vandoeuvre-les-Nancy (France)

    2006-11-15

    The irradiation of a five months pregnant patient has been made for a right parotid attack. In conformation with the legislative texts relative to radiation protection ( publication 84 of the ICRP) an estimation of the dose received for the fetus has been led by dose measurement on phantom. With the dose limit ( 100 mGy) recommended in the publication 84 of the ICRP neither modification of the treatment nor abortion was necessary. (N.C.)

  14. Estimating human cancer risk from the results of animal experiments: relationship between mechanism and dose-rate and dose

    International Nuclear Information System (INIS)

    Experimental animals are often used as surrogate models in estimating human cancer risk from environmental agents when adequate epidemiological data are not available. Studies in experimental animals have usually evaluated the effects of exposure to single substances; however, humans receive combinations of exposures, to both initiators and promoters of carcinogenesis. Exposure to several agents may modify the carcinogenic process of one of them. For many agents, the relationship between dose and carcinogenic response depends on both dose-rate and cumulative dose. For a given total dose, dose-rate may affect carcinogenic potency both qualitatively (target organ) and quantitatively. The effects of dose-rate are a function of total dose, species, and most importantly, the mechanism by which the agent exerts its carcinogenic effect. Prediction of the effects of different dose-rates of potentially carcinogenic agents can be based on knowledge of its mechanism of action.43 references

  15. Estimation of skin dose in interventional neuro and cardiac procedures

    International Nuclear Information System (INIS)

    The dose thresholds for inducing deterministic effects such as erythema and epilation are now within the range of some interventional radiology procedures. It is important to identify those procedures where such dose levels are possible so that more detailed dosimetry and dose reduction can be introduced to minimise the risk of such effects. This paper presents results of work on anthropomorphic phantoms to establish a link between a commonly measured dose indicator (dose-area product) and skin dose, for equipment and geometries commonly used for cardiac and neurological interventional radiology procedures. The results indicate that a conversion to skin dose is equipment specific and furthermore depends on field size and projection. By auditing a sample set of patient data, however, it is possible to identify potentially high dose procedures. (author)

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

    Science.gov (United States)

    Dobynde, M. I.; Shprits, Y.; Drozdov, A.

    2015-12-01

    Time-dependent radiation dose estimations during interplanetary space flights 1,2Dobynde M.I., 2,3Drozdov A.Y., 2,4Shprits Y.Y.1Skolkovo institute of science and technology, Moscow, Russia 2University of California Los Angeles, Los Angeles, USA 3Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, Moscow, Russia4Massachusetts Institute of Technology, Cambridge, USASpace radiation is the main restriction for long-term interplanetary space missions. It induces degradation of external components and propagates inside providing damage to internal environment. Space radiation particles and induced secondary particle showers can lead to variety of damage to astronauts in short- and long- term perspective. Contribution of two main sources of space radiation- Sun and out-of-heliosphere space varies in time in opposite phase due to the solar activity state. Currently the only habituated mission is the international interplanetary station that flights on the low Earth orbit. Besides station shell astronauts are protected with the Earth magnetosphere- a natural shield that prevents significant damage for all humanity. Current progress in space exploration tends to lead humanity out of magnetosphere bounds. With the current study we make estimations of spacecraft parameters and astronauts damage for long-term interplanetary flights. Applying time dependent model of GCR spectra and data on SEP spectra we show the time dependence of the radiation in a human phantom inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease

  17. LASER BIOLOGY: Laser spectroscopy technique for estimating the efficiency of photosensitisers in biological media

    Science.gov (United States)

    Ryabova, A. V.; Stratonnikov, Aleksandr A.; Loshchenov, V. B.

    2006-06-01

    A fast and highly informative method is presented for estimating the photodynamic activity of photosensitisers. The method makes it possible to determine the rate of photodegradation in erythrocyte-containing biological media in nearly in vivo conditions, estimate the degree of irreversible binding of oxygen dissolved in the medium during laser irradiation in the presence of photosensitisers, and determine the nature of degradation of photosensitisers exposed to light (photobleaching).

  18. Biological dose volume histograms during conformal hypofractionated accelerated radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Radiobiological data suggest that prostate cancer has a low α/β ratio. Large radiotherapy fractions may, therefore, prove more efficacious than standard radiotherapy, while radiotherapy acceleration should further improve control rates. This study describes the radiobiology of a conformal hypofractionated accelerated radiotherapy scheme for the treatment of high risk prostate cancer. Anteroposterior fields to the pelvis deliver a daily dose of 2.7 Gy, while lateral fields confined to the prostate and seminal vesicles deliver an additional daily dose of 0.7 Gy. Radiotherapy is accomplished within 19 days (15 fractions). Dose volume histograms, calculated for tissue specific α/β ratios and time factors, predict a high biological dose to the prostate and seminal vesicles (77-93 Gy). The biological dose to normal pelvic tissues is maintained at standard levels. Radiobiological dosimetry suggests that, using hypofractionated and accelerated radiotherapy, high biological radiation dose can be given to the prostate without overdosing normal tissues

  19. Stimulation of biological activities using low radiation doses

    International Nuclear Information System (INIS)

    Hormesis is the excitation, or stimulation, by low doses of any agent in any system; high doses inhibit but low doses stimulate. Don Luckey from the University of Florida identified the phenomenon of radiation hormesis, in 1982. After nearly ten years of data surveys and animal tests in many universities to examine the truth about radiation hormesis, we realized the scientific significance of the stimulating effects caused by low levels of radiation exposure. Stimulation with Ionizing radiation presented evidence of increased vigor in plants, bacteria, invertebrates and vertebrates. Most physiologic reactions in living cells are stimulated by low doses of ionizing radiation. This stimulating effect includes enzyme induction, photosynthesis, respiration and growth. Radiation stimulation to the immune system decreases infection and premature death in radiation exposed individuals. (author)

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

    OpenAIRE

    Gricienė, Birutė

    2010-01-01

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

  1. Dose dependence on stochastic radiobiological effect in radiation risk estimation

    International Nuclear Information System (INIS)

    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

  2. Radiation induced damage to the cells of pig hairs: a biological indicator of radiation dose and dose distribution in skin

    International Nuclear Information System (INIS)

    Radiation damage to the matrix cells of actively growing pig hairs resulted in a transient reduction in diameter. This was clearly dose dependent for doses in the range 0.5-5 Gy for 250 kV X rays and 3-8 Gy surface dose for 90Sr β rays. While the relationship between the percentage reduction in hair diameter and the X ray dose was linear between 0.5 and 5 Gy, the skin surface dose for β rays and the percentage reduction in hair diameter was found to be best fitted by a quadratic equation. Differences in the effect produced by X and β ray irradiation can be attributed to the absorption of β rays with depth in the dermis and a correction for this has been applied. This system would appear to have considerable potential for use as a biological dosemeter. (author)

  3. Biological effects of irradiation on skin and recommended dose limits

    International Nuclear Information System (INIS)

    The range of radiation responses of the skin are reviewed in terms of the time course over which damage is expressed and the likely underlying pathogenesis. Responses of specific concern in radiological protection have been identified; these include acute necrosis/ulceration after exposure to radioactive 'hot' particles, and moist desquamation, late dermal atrophy or telangiectasia after more generalised exposures from intermediate and high energy β emitters. Acute epidermal necrosis is the only endpoint of concern after exposure to low energy β emitters. Dose-effect relationships have been established for each of these responses and on this basis recommendations for dose limitation for the skin can be made along with proposals for the depths at which dose should be assessed in routine monitoring procedures. (author)

  4. Estimation of dose uncertainty measurement in a Nuclear Medicine Service

    International Nuclear Information System (INIS)

    Full text: The accuracy of activity measurement is the first step in safety and radiation protection of patient. The uncertainty of activity measurement has a lot of aspect to take into account: calibration factors, geometric of the sample, position, stability of the equipment parameters, stability, etc. More over, operational parameters change between different equipment, for that reason guarantee the traceability of measurement is very important in quality assurance. The objective of this study was determined the combine uncertainty of activity measurement for isotopes I131 and Tc99m , using dose calibrators well establish in Latin American countries Capintec CRC-15R and PTW Curimentor 3 those present in our Nuclear Medicine Service. The uncertainty could be defined as a parameter associated with the result of a measurement, which characterises the dispersion of the values that could reasonably be attributed to the measured. The parameter may be, for example, a standard deviation (or a given multiple of it), or the width of a confidence interval. Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of series of measurements and can be characterised by standard deviations. The other components, which also can be characterised by standard deviations, are evaluated from assumed probability distributions based on experience or other information. These different cases are defining as Type A and Type B estimations respectively. The combine uncertainty is calculated as the square root of the square sum of all uncertainty components. These uncertainties are associates to calibration factor, linearity, reproducibility, radioactive background, stability, radioactive decay correction, etc. For that reason the performance of accuracy, precision, the linearity of activity response and reproducibility were study during 6 month. In order to check the precision and accuracy

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

    International Nuclear Information System (INIS)

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

  6. Radiobiological impact of dose calculation algorithms on biologically optimized IMRT lung stereotactic body radiation therapy plans

    International Nuclear Information System (INIS)

    The aim of this study is to evaluate the radiobiological impact of Acuros XB (AXB) vs. Anisotropic Analytic Algorithm (AAA) dose calculation algorithms in combined dose-volume and biological optimized IMRT plans of SBRT treatments for non-small-cell lung cancer (NSCLC) patients. Twenty eight patients with NSCLC previously treated SBRT were re-planned using Varian Eclipse (V11) with combined dose-volume and biological optimization IMRT sliding window technique. The total dose prescribed to the PTV was 60 Gy with 12 Gy per fraction. The plans were initially optimized using AAA algorithm, and then were recomputed using AXB using the same MUs and MLC files to compare with the dose distribution of the original plans and assess the radiobiological as well as dosimetric impact of the two different dose algorithms. The Poisson Linear-Quadatric (PLQ) and Lyman-Kutcher-Burman (LKB) models were used for estimating the tumor control probability (TCP) and normal tissue complication probability (NTCP), respectively. The influence of the model parameter uncertainties on the TCP differences and the NTCP differences between AAA and AXB plans were studied by applying different sets of published model parameters. Patients were grouped into peripheral and centrally-located tumors to evaluate the impact of tumor location. PTV dose was lower in the re-calculated AXB plans, as compared to AAA plans. The median differences of PTV(D95%) were 1.7 Gy (range: 0.3, 6.5 Gy) and 1.0 Gy (range: 0.6, 4.4 Gy) for peripheral tumors and centrally-located tumors, respectively. The median differences of PTV(mean) were 0.4 Gy (range: 0.0, 1.9 Gy) and 0.9 Gy (range: 0.0, 4.3 Gy) for peripheral tumors and centrally-located tumors, respectively. TCP was also found lower in AXB-recalculated plans compared with the AAA plans. The median (range) of the TCP differences for 30 month local control were 1.6 % (0.3 %, 5.8 %) for peripheral tumors and 1.3 % (0.5 %, 3.4 %) for centrally located tumors. The lower TCP

  7. Estimation of parameters of dose-volume models and their confidence limits

    International Nuclear Information System (INIS)

    Predictions of the normal-tissue complication probability (NTCP) for the ranking of treatment plans are based on fits of dose-volume models to clinical and/or experimental data. In the literature several different fit methods are used. In this work frequently used methods and techniques to fit NTCP models to dose response data for establishing dose-volume effects, are discussed. The techniques are tested for their usability with dose-volume data and NTCP models. Different methods to estimate the confidence intervals of the model parameters are part of this study. From a critical-volume (CV) model with biologically realistic parameters a primary dataset was generated, serving as the reference for this study and describable by the NTCP model. The CV model was fitted to this dataset. From the resulting parameters and the CV model, 1000 secondary datasets were generated by Monte Carlo simulation. All secondary datasets were fitted to obtain 1000 parameter sets of the CV model. Thus the 'real' spread in fit results due to statistical spreading in the data is obtained and has been compared with estimates of the confidence intervals obtained by different methods applied to the primary dataset. The confidence limits of the parameters of one dataset were estimated using the methods, employing the covariance matrix, the jackknife method and directly from the likelihood landscape. These results were compared with the spread of the parameters, obtained from the secondary parameter sets. For the estimation of confidence intervals on NTCP predictions, three methods were tested. Firstly, propagation of errors using the covariance matrix was used. Secondly, the meaning of the width of a bundle of curves that resulted from parameters that were within the one standard deviation region in the likelihood space was investigated. Thirdly, many parameter sets and their likelihood were used to create a likelihood-weighted probability distribution of the NTCP. It is concluded that for the

  8. Coincidence in the dose estimation in a OEP by different methods; Coincidencia en la estimacion de dosis en un POE por diferentes metodos

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero C, C.; Arceo M, C.; Brena V, M. [ININ, Km. 36.5, Carretera Mexico-Toluca, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: cgc@nuclear.inin.mx

    2007-07-01

    The case of an apparent overexposure to radiation according to that indicated for the thermoluminescent dosemeter 81.59 mSv (TLD) of a occupationally exposed hard-working (POE), for that was practiced the study of biological dosimetry. The estimated dose was 0.12 Gy with which was proven the marked dose registration by the TLD dosemeter. It was concluded that both doses are the same ones. (Author)

  9. Estimation of Fetal Dose during Radiation Therapy of Pregnant Patient

    International Nuclear Information System (INIS)

    To evaluate the effectiveness of a simple and practical shielding device to reduce the fetal dose for a pregnant patient undergoing radiation therapy of brain metastasis. The dose to the fetus was evaluated by simulating the treatments using the anthropomorphic phantom. The prescription dose at mid-brain is 300 cGy x 10 fractions with 6 MV photon with 18 x 22 cm2 field size. The additional shielding devices to reduce the fetal dose are a shielding wall, cerrobend plates and lead (Pb) sheets over acrylic bridge. Various points of measurement with off-field distance were detected by using ion-chamber (30, 40, 50, and 60 cm) with and without the shielding devices and TLD (30, 40, 50, 60, and 70 cm) only with the shielding devices. The doses to the fetus without shielding were 3.20, 3.21, 1.44, 0.90 cGy at the distances of 30, 40, 50, and 60 cm from the treatment field edge. With shielding, the doses were reduced to 0.88, 0.60, 0.35, 0.25 cGy, and the ratio of the shielding effect varied from 70% to 80%. TLD results were 1.8, 1.2, 0.8, 1.2, and 0.8 cGy (70 cm). The total dose to the fetus was expected to be under 1 cGy during the entire treatment. The essential point during radiation therapy of pregnant patient would be minimizing the fetal dose. 10 cGy to 20 cGy is the threshold dose for fetal radiation effects. Our newly developed device reduced the fetal dose far below the safe level. Therefore, our additional shielding devices are useful and effective to reduce the fetal dose.

  10. The estimation of effective doses using measurement of several relevant physical parameters from radon exposures

    International Nuclear Information System (INIS)

    In the present investigation, we will be study the dose relevant factors from continual monitoring in real homes into account getting more accurate estimation of 222Rn the effective dose. The dose relevant parameters include the radon concentration, the equilibrium factor (f), the fraction (fp) of unattached radon decay products and real time occupancy people in home. The result of the measurement are the time courses of radon concentration that are based on estimation effective doses together with assessment of the real time occupancy people indoor. We found out by analysis that year effective dose is lower than effective dose estimated by ICRP recommendation from the integral measurement that included only average radon concentration. Our analysis of estimation effective doses using measurement of several physical parameters was made only in one case and for the better specification is important to measure in different real occupancy houses. (authors)

  11. Effective dose estimation to patients and staff during urethrography procedures

    Energy Technology Data Exchange (ETDEWEB)

    Sulieman, A. [Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P. O- Box 422, Alkharj 11942 (Saudi Arabia); Barakat, H. [Neelain University, College of Science and Technology, Medical Physics Department, Khartoum (Sudan); Alkhorayef, M.; Babikir, E. [King Saud University, College of Applied Sciences, Radiological Sciences Department, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Dalton, A.; Bradley, D. [University of Surrey, Centre for Nuclear and Radiation Physics, Department of Physics, Surrey, GU2 7XH Guildford (United Kingdom)

    2015-10-15

    Medical-related radiation is the largest source of controllable radiation exposure to humans and it accounts for more than 95% of radiation exposure from man-made sources. Few data were available worldwide regarding patient and staff dose during urological ascending urethrography (ASU) procedure. The purposes of this study are to measure patient and staff entrance surface air kerma dose (ESAK) during ASU procedure and evaluate the effective doses. A total of 243 patients and 145 staff (Urologist) were examined in three Hospitals in Khartoum state. ESAKs were measured for patient and staff using thermoluminescent detectors (TLDs). Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB). The mean ESAK dose for patients and staff dose were 7.79±6.7 mGy and 0.161±0.30 mGy per procedures respectively. The mean and range of the effective dose was 1.21 mSv per procedure. The radiation dose in this study is comparable with previous studies except Hospital C. It is obvious that high patient and staff exposure is due to the lack of experience and protective equipment s. Interventional procedures remain operator dependent; therefore continuous training is crucial. (Author)

  12. Effective dose estimation to patients and staff during urethrography procedures

    International Nuclear Information System (INIS)

    Medical-related radiation is the largest source of controllable radiation exposure to humans and it accounts for more than 95% of radiation exposure from man-made sources. Few data were available worldwide regarding patient and staff dose during urological ascending urethrography (ASU) procedure. The purposes of this study are to measure patient and staff entrance surface air kerma dose (ESAK) during ASU procedure and evaluate the effective doses. A total of 243 patients and 145 staff (Urologist) were examined in three Hospitals in Khartoum state. ESAKs were measured for patient and staff using thermoluminescent detectors (TLDs). Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB). The mean ESAK dose for patients and staff dose were 7.79±6.7 mGy and 0.161±0.30 mGy per procedures respectively. The mean and range of the effective dose was 1.21 mSv per procedure. The radiation dose in this study is comparable with previous studies except Hospital C. It is obvious that high patient and staff exposure is due to the lack of experience and protective equipment s. Interventional procedures remain operator dependent; therefore continuous training is crucial. (Author)

  13. Estimation of doses to patients with chronic radiation sickness from external occupational exposure

    International Nuclear Information System (INIS)

    The doses to patients with chronic radiation sickness who had engaged in diagnostic radiology have been estimated according to the radiation work load, type and capacity of X-ray equipment, protection conditions, data of nationwide survey on doses to X-ray workers in China, or the data of dose monitoring in working places. Based on the activities of radium sources, time taken up in performing radium therapy, distance to radium sources and radiation work load, the doses to patients who had engaged in radium therapy have been estimated. The results of estimated average doses for 29 cases of chronic radiation sickness are given. Their average red marrow dose, trunk dose and effective dose equivalent are 1.3 Gy, 1.2 Gy and 1.6 Sv, respectively

  14. Novel metaheuristic for parameter estimation in nonlinear dynamic biological systems

    Directory of Open Access Journals (Sweden)

    Banga Julio R

    2006-11-01

    Full Text Available Abstract Background We consider the problem of parameter estimation (model calibration in nonlinear dynamic models of biological systems. Due to the frequent ill-conditioning and multi-modality of many of these problems, traditional local methods usually fail (unless initialized with very good guesses of the parameter vector. In order to surmount these difficulties, global optimization (GO methods have been suggested as robust alternatives. Currently, deterministic GO methods can not solve problems of realistic size within this class in reasonable computation times. In contrast, certain types of stochastic GO methods have shown promising results, although the computational cost remains large. Rodriguez-Fernandez and coworkers have presented hybrid stochastic-deterministic GO methods which could reduce computation time by one order of magnitude while guaranteeing robustness. Our goal here was to further reduce the computational effort without loosing robustness. Results We have developed a new procedure based on the scatter search methodology for nonlinear optimization of dynamic models of arbitrary (or even unknown structure (i.e. black-box models. In this contribution, we describe and apply this novel metaheuristic, inspired by recent developments in the field of operations research, to a set of complex identification problems and we make a critical comparison with respect to the previous (above mentioned successful methods. Conclusion Robust and efficient methods for parameter estimation are of key importance in systems biology and related areas. The new metaheuristic presented in this paper aims to ensure the proper solution of these problems by adopting a global optimization approach, while keeping the computational effort under reasonable values. This new metaheuristic was applied to a set of three challenging parameter estimation problems of nonlinear dynamic biological systems, outperforming very significantly all the methods previously

  15. Estimating Annual Individual Doses for Evacuees Returning Home to Areas Affected by the Fukushima Nuclear Accident.

    Science.gov (United States)

    Yajima, Kazuaki; Kurihara, Osamu; Ohmachi, Yasushi; Takada, Masashi; Omori, Yasutaka; Akahane, Keiichi; Kim, Eunjoo; Torikoshi, Masami; Yonehara, Hidenori; Yoshida, Satoshi; Sakai, Kazuo; Akashi, Makoto

    2015-08-01

    To contribute to the reconstruction and revitalization of Fukushima Prefecture following the 2011 nuclear power disaster, annual individual doses were estimated for evacuees who will return home to Tamura City, Kawauchi Village, and Iitate Village in Fukushima. Ambient external dose rates and individual doses obtained with personal dosimeters were measured at many residential and occupational sites throughout the study areas to obtain fundamental data needed for the estimation. The measurement results indicated that the ratio of individual dose based on a personal dosimeter to the ambient external dose measurement was 0.7 with 10% uncertainty. Multiplying the ambient external dose by 0.7 may be an appropriate measure of the effective dose to an individual in the investigated area. Annual individual doses were estimated for representative lifestyles and occupations based on the ambient external dose rates at the measurement sites, taking into account the relationship between the ambient external dose and individual dose. The results were as follows: 0.6-2.3 mSv y in Tamura, 1.1-5.5 mSv y in Kawauchi, and 3.8-17 mSv y in Iitate. For all areas investigated, the estimated dose to outdoor workers was higher than that to indoor workers. Identifying ways to reduce the amount of time that an outdoor worker spends outdoors would provide an effective measure to reduce dose. PMID:26107433

  16. Contribution of the modulation of intensity and the optimization to deliver a dose adapted to the biological heterogeneities

    International Nuclear Information System (INIS)

    The recent progress in functional imaging by Positron Emission Tomography (TEP) opens new perspectives in the delineation of target volumes in radiotherapy. The functional data is major; we can intend to adapt the irradiation doses on the tumor activity (TA) and to perform a dose escalation. Our objectives were (i) to characterize the TEP threshold, by quantifying the uncertainties of the target volume contour according to the lesion size and the threshold contour level, (ii) to set up the geometry suited to perform a high-precision irradiation based on the TA, (iii) to estimate the dosimetric impact of this new protocol and (iv) to verify that dosimetry is perfectly distributed. Three original phantoms were specially created to satisfy the constraints met, as well as two virtual phantoms containing 3 dose levels (dose level 3 = TA). Our results showed the importance of the effect threshold-volume on the planning in radiotherapy. To use this irradiation method, the diameter of 1 cm for the third level was able to be reached. A dose escalation of 20 Gy was possible between the second (70 Gy) and the third level (90 Gy). The dosimetric impact estimated on two real cases was suitable - increase of COIN (conformal index) from 0.6 to 0.8 and decrease of NTCP (normal tissue complication probability) of a factor 5 -. In absolute and relative dosimetry, the clinical tolerances were respected. So all the treatment process, going from the diagnosis with the TEP to reveal the TA, to the patient treatment made beforehand on phantom, and going through the ballistic and the dose calculation, was estimated and validated according to our objective to adapt the irradiation to the biological heterogeneities. However such high doses should be carefully estimated before being prescribed clinically and progress is also expected in imaging, because the minimal size which we can irradiate is on the limit of the resolution TEP. (author)

  17. Requirements for estimation of doses from contaminants dispersed by a 'dirty bomb' explosion in an urban area

    International Nuclear Information System (INIS)

    The ARGOS decision support system is currently being extended to enable estimation of the consequences of terror attacks involving chemical, biological, nuclear and radiological substances. This paper presents elements of the framework that will be applied in ARGOS to calculate the dose contributions from contaminants dispersed in the atmosphere after a 'dirty bomb' explosion. Conceptual methodologies are presented which describe the various dose components on the basis of knowledge of time-integrated contaminant air concentrations. Also the aerosolisation and atmospheric dispersion in a city of different types of conceivable contaminants from a 'dirty bomb' are discussed.

  18. Estimation and uncertainty analysis of dose response in an inter-laboratory experiment

    Science.gov (United States)

    Toman, Blaza; Rösslein, Matthias; Elliott, John T.; Petersen, Elijah J.

    2016-02-01

    An inter-laboratory experiment for the evaluation of toxic effects of NH2-polystyrene nanoparticles on living human cancer cells was performed with five participating laboratories. Previously published results from nanocytoxicity assays are often contradictory, mostly due to challenges related to producing a reliable cytotoxicity assay protocol for use with nanomaterials. Specific challenges include reproducibility preparing nanoparticle dispersions, biological variability from testing living cell lines, and the potential for nano-related interference effects. In this experiment, such challenges were addressed by developing a detailed experimental protocol and using a specially designed 96-well plate layout which incorporated a range of control measurements to assess multiple factors such as nanomaterial interference, pipetting accuracy, cell seeding density, and instrument performance. Detailed data analysis of these control measurements showed that good control of the experiments was attained by all participants in most cases. The main measurement objective of the study was the estimation of a dose response relationship between concentration of the nanoparticles and metabolic activity of the living cells, under several experimental conditions. The dose curve estimation was achieved by imbedding a three parameter logistic curve in a three level Bayesian hierarchical model, accounting for uncertainty due to all known experimental conditions as well as between laboratory variability in a top-down manner. Computation was performed using Markov Chain Monte Carlo methods. The fit of the model was evaluated using Bayesian posterior predictive probabilities and found to be satisfactory.

  19. Dose estimation and dating of pottery from Turkey

    Science.gov (United States)

    Altay Atlıhan, M.; Şahiner, Eren; Soykal Alanyalı, Feriştah

    2012-06-01

    The luminescence method is a widely used technique for environmental dosimetry and dating archaeological, geological materials. In this study, equivalent dose (ED) and annual dose rate (AD) of an archaeological sample were measured. The age of the material was calculated by means of equivalent dose divided by the annual dose rate. The archaeological sample was taken from Antalya, Turkey. Samples were prepared by the fine grain technique and equivalent dose was found using multiple-aliquot-additive-dose (MAAD) and single aliquot regeneration (SAR) techniques. Also the short shine normalization-MAAD and long shine normalization-MAAD were applied and the results of the methods were compared with each other. The optimal preheat temperature was found to be 200 °C for 10 min. The annual doses of concentrations of the major radioactive isotopes were determined using a high-purity germanium detector and a low-level alpha counter. The age of the sample was found to be 510±40 years.

  20. Biological effects of low doses of ionising radiation

    International Nuclear Information System (INIS)

    A study was performed with the aim to examine whether the progeny of cells that had been repeatedly irradiated with low doses of gamma rays will change their sensitivity to cytotoxic agents. Four mammalian cell lines were used in the experiment. It was found that the progeny of cells irradiated in this way do not change their sensitivity to gamma rays but would change their sensitivity to various cytostatics drugs. (A.K.)

  1. The biological basis for dose limitation to the skin

    International Nuclear Information System (INIS)

    Ionizing radiation may cause deterministic effects and cancer. It has been the policy to base dose limits for radiation protection of the skin on the prevention of deterministic effects (1). In the case of cancer in general, dose limitation for radiation protection is based on limiting excess cancer mortality to low levels of radiation. Since skin cancers are seldom lethal, the general radiation protection standards will protect against an increase in excess mortality from skin cancer. However, with the dose limits selected to prevent deterministic effects, there is a significant probability of an excess incidence of skin cancer occurring as a result of exposure during a working lifetime. The induction of skin cancer by radiation is influenced significantly by subsequent exposure to ultraviolet radiation (UVR) from sunlight. This finding raises not only interesting questions about the mechanisms involved, but also about the differences in risk of skin cancer in different populations. The amount and distribution of melanin in the skin determines the degree of the effect of UVR. This paper discusses the mechanisms of the induction of both deterministic and stochastic effects in skin exposed to radiation in relation to radiation protection. (author)

  2. Convolution-based estimation of organ dose in tube current modulated CT.

    Science.gov (United States)

    Tian, Xiaoyu; Segars, W Paul; Dixon, Robert L; Samei, Ehsan

    2016-05-21

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460-7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18-70 years, weight range: 60-180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ([Formula: see text]) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate [Formula: see text] values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying [Formula: see text] with the organ dose coefficients ([Formula: see text]). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled. The discrepancy between the estimated organ dose and dose simulated using TCM Monte Carlo program was quantified. We further compared the

  3. Convolution-based estimation of organ dose in tube current modulated CT

    Science.gov (United States)

    Tian, Xiaoyu; Segars, W. Paul; Dixon, Robert L.; Samei, Ehsan

    2016-05-01

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460–7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18–70 years, weight range: 60–180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ({{h}\\text{Organ}} ) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} with the organ dose coefficients ({{h}\\text{Organ}} ). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled

  4. Absorbed Doses and Risk Estimates of (211)At-MX35 F(ab')2 in Intraperitoneal Therapy of Ovarian Cancer Patients

    DEFF Research Database (Denmark)

    Cederkrantz, Elin; Andersson, Håkan; Bernhardt, Peter;

    2015-01-01

    , intraperitoneal (i.p.) targeted α therapy has been proposed as an adjuvant treatment for minimal residual disease after successful primary treatment. In the present study, we calculated absorbed and relative biological effect (RBE)-weighted (equivalent) doses in relevant normal tissues and estimated the effective...... infused therapy solution. RESULTS: The urinary bladder, thyroid, and kidneys (1.9, 1.8, and 1.7 mGy per MBq/L) received the 3 highest estimated absorbed doses. When the tissue-weighting factors were applied, the largest contributors to the effective dose were the lungs, stomach, and urinary bladder. Using...... 100 MBq/L, organ equivalent doses were less than 10% of the estimated tolerance dose. CONCLUSION: Intraperitoneal (211)At-MX35 F(ab')2 treatment is potentially a well-tolerated therapy for locally confined microscopic ovarian cancer. Absorbed doses to normal organs are low, but because the effective...

  5. A unified framework for benchmark dose estimation applied to mixed models and model averaging

    DEFF Research Database (Denmark)

    Ritz, Christian; Gerhard, Daniel; Hothorn, Ludwig A.

    2013-01-01

    This article develops a framework for benchmark dose estimation that allows intrinsically nonlinear dose-response models to be used for continuous data in much the same way as is already possible for quantal data. This means that the same dose-response model equations may be applied to both...

  6. Computer subroutines for the estimation of nuclear reaction effects in proton-tissue-dose calculations

    Science.gov (United States)

    Wilson, J. W.; Khandelwal, G. S.

    1976-01-01

    Calculational methods for estimation of dose from external proton exposure of arbitrary convex bodies are briefly reviewed. All the necessary information for the estimation of dose in soft tissue is presented. Special emphasis is placed on retaining the effects of nuclear reaction, especially in relation to the dose equivalent. Computer subroutines to evaluate all of the relevant functions are discussed. Nuclear reaction contributions for standard space radiations are in most cases found to be significant. Many of the existing computer programs for estimating dose in which nuclear reaction effects are neglected can be readily converted to include nuclear reaction effects by use of the subroutines described herein.

  7. Estimates of collective doses from a hypothetical accident of a nuclear submarine

    International Nuclear Information System (INIS)

    The collective dose to the Japanese population has been estimated from a hypothetical accident of a nuclear submarine if it sinks in an offshore region around Japan. A computer code system DSOCEAN has been used for assessing the collective dose due to radionuclides released to the ocean from a sunken nuclear submarine. The estimated collective effective dose commitment from all of the radionuclides released after the break of the fuel pellets is estimated to be 2.5 x l04 man·Sv. The contribution of 241 Am to the total collective effective dose commitment is the highest, followed by 137Cs, 238Pu, 240Pu, 239Pu and 241Pu. The maximum of the estimated collective effective dose by the annual intake of marine products after radionuclide releases for one year is approximately 0.3% of the annual average dose by the natural radiation that is reported by UNSCEAR. (author)

  8. Estimation of personal dose while processing NORM contaminated metal scrap

    International Nuclear Information System (INIS)

    In 1998 Siempelkamp Nukleartechnik started to operate a special melting shop at the Krefeld site. Contaminated metal scrap resulting from decommissioning of natural oil and gas production plants, the mining industry, fertilizer production and groundwater extraction is melted in order to transfer the contamination such as mercury and NORM into the slag and the dust, enabling the decontaminated metal to be recycled. Usually, NORM contamination results from the radium decay chain 226Ra and/or from the thorium decay chain. According to the German radiation protection ordinance, based on the Euratom radiation protection recommendations, an observation of the working areas is necessary if the dose caused by NORM during the total disposal process exceeds 1 mSv/a. To determine the worker doses, measurements were made in 2005 in various ways. Besides long term TLD dose measurements, workplaces were measured with electronic dosimeters for 24 h periods. Additionally, the workers wore personal dosimeters during their working time. The working time at each workplace was documented to be able to weight the daily dose for the specific workplace. Contrary to the dose from external radiation, a former study has shown that incorporation of radionuclides into the body is negligible. Due to the possible mercury concentration in the air, all of the workers wear breathing apparatus with a filtration factor of 99.997%. No radioactivity has been detected by urine analyses. The resulting personal doses calculated from the measurements are approximately 0.08-0.3 mSv/a, which is in the range of previous results, ascertained only by TLD dose measurements. (author)

  9. Estimated neutron dose to embryo and foetus during commercial flight.

    Science.gov (United States)

    Chen, J; Lewis, B J; Bennett, L G I; Green, A R; Tracy, B L

    2005-01-01

    A study has been carried out to assess the radiation exposure from cosmic-ray neutrons to the embryo and foetus of pregnant aircrew and air travellers in consideration of the radiation exposure from cosmic-ray neutrons to the embryo and foetus. A Monte Carlo analysis was performed to determine the equivalent dose from neutrons to the brain and body of an embryo at 8 weeks and to the foetus at the 3, 6 and 9 month periods. Neutron fluence-to-absorbed dose conversion coefficients for the foetal brain and for the entire foetal body (isotropic irradiation geometry) have been determined at the four developmental stages. The equivalent dose rate to the foetus during commercial flights has been further evaluated considering the fluence-to-absorbed dose conversion coefficients, a neutron spectrum measured at an altitude of 11.3 km and an ICRP-92 radiation-weighting factor for neutrons. This study indicates that the foetus can exceed the annual dose limit of 1 mSv for the general public after, for example, 15 round trips on commercial trans-Atlantic flights. PMID:15860538

  10. Application of cytogenetic methods for estimation of absorbed dose

    International Nuclear Information System (INIS)

    Accumulated data on the practical application of cytogenetic technique to evaluate the absorbed dose for men involved in activities to eliminate the effects of the Chernobyl NPP accident were analyzed. Those data were compared with the results of cytogenetic studies conducted in other Russia regions affected by radiation impacts (Muslyumovo settle., Chelyabinsk Region, the Altay Territory settlements near the Semipalatinsk test range) and with the examination results of population of the territory of the Three Mile Island NPP (Island, Pennsylvania, USA) where in 1975 the nuclear accident took place. The cytogenetic studies were carried out using the standard analysis technique evaluating the frequency of unstable aberrations of chromosomes (UA) and using FISH-technique designed to evaluate the frequency of stable aberrations of chromosomes. It was pointed out that UA-technique could not be used efficiently for the retrospective evaluation of the absorbed doses with no clear idea correlating the nature and the rate of elimination with cell life time, especially, in case of small doses of irradiation. Analysis of the stable translocation using FISH-technique enabled to evaluate the absorbed dose within 8-9 years following the accident. The range of the absorbed doses of the examined persons varied from the background ones up to 1 Gy

  11. Age- and sex-dependent model for estimating radioiodine dose to a normal thyroid

    International Nuclear Information System (INIS)

    This paper describes the derivation of an age- and sex-dependent model of radioiodine dosimetry in the thyroid and the application of the model to estimating the thyroid dose for each of 4215 patients who were exposed to 131I in diagnostic and therapeutic procedures. The model was made to conform to these data requirements by the use of age-specific estimates of the biological half-time of iodine in the thyroid and an age- and sex-dependent representation of the mass of the thyroid. Also, it was assumed that the thyroid burden was maximum 24 hours after administration (the 131I dose is not critically sensitive to this assumption). The metabolic model is of the form A(t) = K[exp(-μ1t) - exp(-μ2t)] (μCi), where μ1 = lambda/sub r/ + lambda/sub i//sup b/ (i = 1, 2), lambda/sub r/ is the radiological decay-rate coefficient, and lambda/sub i//sup b/ are biological removal rate coefficients. The values of lambda/sub i//sup b/ are determined by solving a nonlinear equation that depends on assumptions about the time of maximum uptake and the eventual biological loss rate (through which age dependence enters). The value of K may then be calculated from knowledge of the uptake at a particular time. The dosimetric S-factor (rad/μCi-day) is based on specific absorbed fractions for photons of energy ranging from 0.01 to 4.0 MeV for thyroid masses from 1.29 to 19.6 g; the functional form of the S-factor also involves the thyroid mass explicitly, through which the dependence on age and sex enters. An analysis of sensitivity of the model to uncertainties in the thyroid mass and the biological removal rate for several age groups is reported. The model could prove useful in the dosimetry of very short-lived radioiodines. Tables of age- and sex-dependent coefficients are provided to enable readers to make their own calculations. 12 refs., 5 figs., 4 tabs

  12. Biological effectiveness on live cells of laser driven protons at dose rates exceeding 109 Gy/s

    International Nuclear Information System (INIS)

    The ultrashort duration of laser-driven multi-MeV ion bursts offers the possibility of radiobiological studies at extremely high dose rates. Employing the TARANIS Terawatt laser at Queen's University, the effect of proton irradiation at MeV-range energies on live cells has been investigated at dose rates exceeding 109 Gy/s as a single exposure. A clonogenic assay showed consistent lethal effects on V-79 live cells, which, even at these dose rates, appear to be in line with previously published results employing conventional sources. A Relative Biological Effectiveness (RBE) of 1.4±0.2 at 10% survival is estimated from a comparison with a 225 kVp X-ray source.

  13. Physics must join with biology in better assessing risk from low-dose irradiation

    International Nuclear Information System (INIS)

    This review summarises the complex response of mammalian cells and tissues to low doses of ionising radiation. This thesis encompasses induction of DNA damage, and adaptive protection against both renewed damage and against propagation of damage from the basic level of biological organisation to the clinical expression of detriment. The induction of DNA damage at low radiation doses apparently is proportional to absorbed dose at the physical/chemical level. However, any propagation of such damage to higher levels of biological organisation inherently follows a sigmoid function. Moreover, low-dose-induced inhibition of damage propagation is not linear, but instead follows a dose-effect function typical for adaptive protection, after an initial rapid rise it disappears at doses higher than ∼0.1-0.2 Gy to cells. The particular biological response duality at low radiation doses precludes the validity of the linear-no-threshold hypothesis in the attempt to relate absorbed dose to cancer. In fact, theory and observation support not only a lower cancer incidence than expected from the linear-no-threshold hypothesis, but also a reduction of spontaneously occurring cancer, a hormetic response, in the healthy individual. (authors)

  14. Dose estimative in operators during petroleum wells logging with nuclear wireless probes through computer modelling

    International Nuclear Information System (INIS)

    This paper evaluates the absorbed dose and the effective dose on operators during the petroleum well logging with nuclear wireless that uses gamma radiation sources. To obtain the data, a typical scenery of a logging procedure will be simulated with MCNPX Monte Carlo code. The simulated logging probe was the Density Gamma Probe - TRISOND produced by Robertson Geolloging. The absorbed dose values were estimated through the anthropomorphic simulator in male voxel MAX. The effective dose values were obtained using the ICRP 103

  15. Retrospective dosimetry: Estimation of the dose to quartz using the single-aliquot regenerative-dose protocol

    DEFF Research Database (Denmark)

    Banerjee, D.; Bøtter-Jensen, L.; Murray, A.S.

    2000-01-01

    We report on the application of the single-aliquot regenerative-dose protocol to retrospective dosimetry, using the optically stimulated luminescence (OSL) from quartz extracted from fired bricks. These bricks had previously been exposed to enhanced levels of ionising radiation while part of...... meets the fundamental requirement of the single-aliquot regenerative-dose protocol, in that any change in the luminescence recombination probability can be corrected for by using the OSL response to a fixed test dose. The response of a particular aliquot is examined after three different treatments...... (untreated, reset by exposure to light and reset by heating to 500 degrees C) and it is shown that, after sensitivity correction, the dose-response curves are indistinguishable up to 10 Gy. The routine application of the protocol is then described and dose estimates are shown to be insensitive to preheat...

  16. Patient absorbed radiation doses estimation related to irradiation anatomy; Estimativa de dose absorvida pelo paciente relacionada a anatomia irradiada

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes, E-mail: prof.flavio@gmail.com, E-mail: amanda-a-soares@hotmail.com, E-mail: gabriellygkahl@gmail.com [Instituto Federal de Eduacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis, SC (Brazil)

    2014-07-01

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

  17. Uncertainties in effective dose estimates of adult CT head scans: The effect of head size

    International Nuclear Information System (INIS)

    Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT-EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes. Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads. Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%-31% (CT-EXPO), 15%-30% (CTDOSIMETRY), 20%-36% (IMPACTDOSE), and 31%-40% (DLP). Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

  18. Dose estimation for the eye lens dealing with radioactive wastes

    International Nuclear Information System (INIS)

    A significant reduction of the dose limit for the lens of the eye is currently discussed in international committees. The ICRP had recommended a reduction from 150 mSv to 20 mSv, the IAEA-BSS have already adopted this value and the Euratom-BSS propose this too. In the practice of radiation protection the compliance with the limit for the lens of the eye has played a minor role so far. This was in practice assured by the compliance with the limit for the effective dose. With a possible stipulation of a much lower value in the Radiation Protection Ordinance (StrlSchV), the question of compliance arises again. When handling radioactive waste where often gamma radiation is dominant it may happen that the (unshielded) eye region is much more exposed as the location of the (shielded) personal dosimeter. A theoretical study of typical GNS-workplaces in radioactive waste management has shown that up to a factor of 4 higher exposures may occur. A generic assessment under very conservative assumptions that was done first did not allow for the conclusion that the compliance of the new dose limit for the lens of the eye is given by complying with the limit for the effective dose. To get a more reliable basis the exposure situation will now be investigated by measurements that are carried out with specific TLDs provided by the MPA Dortmund. (orig.)

  19. Internal dose estimation by bio-assay techniques

    International Nuclear Information System (INIS)

    Radiation exposure, both external and internal, can occur to radiation workers during the operation of various nuclear fuel cycle facilities and radiation facilities. The assessment of radiation doses to workers, routinely or potentially exposed to radiation, through intake of radionuclide is an integral part of the radiation protection programme. Internal dose is the radiation exposure that results from the intake of radioactive materials into the body by inhalation, ingestion, absorption through the skin or via wounds. Assessment of radiation doses arising from the intake of radioactive material by the workers is termed as internal exposure assessment. Unlike external exposure, internal exposure cannot be measured directly. Its evaluation is based on the calculation of the intake of radionuclide either from direct measurements (e.g, external monitoring of whole body or of specific organs and tissues) or indirect measurements (e.g. radioactivity in urine, faeces, breath or samples from the working environment) (ICRP Pub. 78, 1997 and NRPB-W60, 2004). Another method of internal dose assessment is based on the measurement of airborne radionuclides in the working areas of the facility and the worker's occupancy in those areas

  20. A simplified method to estimate gamma dose from atmospheric releases

    International Nuclear Information System (INIS)

    Computation of gamma dose due to atmospheric releases is a tedious and time consuming process needing a large and fast computer. A simple approximate procedure is evolved which circumvents the need of a large body of precalculated data. Error analysis of the method is also presented. (author)

  1. Major cost savings associated with biologic dose reduction in patients with inflammatory arthritis.

    LENUS (Irish Health Repository)

    Murphy, C L

    2015-01-01

    The purpose of this study was to explore whether patients with Inflammatory Arthritis (IA) (Rheumatoid Arthritis (RA), Psoriatic Arthritis (PsA) or Ankylosing Spondylitis (AS)) would remain in remission following a reduction in biologic dosing frequency and to calculate the cost savings associated with dose reduction. This prospective non-blinded non-randomised study commenced in 2010. Patients with Inflammatory Arthritis being treated with a biologic agent were screened for disease activity. A cohort of those in remission according to standardized disease activity indices (DAS28 < 2.6, BASDAI < 4) was offered a reduction in dosing frequency of two commonly used biologic therapies (etanercept 50 mg once per fortnight instead of weekly, adalimumab 40 mg once per month instead of fortnightly). Patients were assessed for disease activity at 3, 6, 12, 18 and 24 months following reduction in dosing frequency. Cost saving was calculated. 79 patients with inflammatory arthritis in remission were recruited. 57% had rheumatoid arthritis (n = 45), 13% psoriatic arthritis (n = 10) and 30% ankylosing spondylitis (n = 24). 57% (n = 45) were taking etanercept and 43% (n = 34) adalimumab. The percentage of patients in remission at 24 months was 56% (n = 44). This resulted in an actual saving to the state of approximately 600,000 euro over two years. This study demonstrates the reduction in biologic dosing frequency is feasible in Inflammatory Arthritis. There was a considerable cost saving at two years. The potential for major cost savings in biologic usage should be pursued further.

  2. Imprecision in predicted dose from 137Cs resulting from biological variability

    International Nuclear Information System (INIS)

    The variability of observed values of human metabolic and physiological characteristics which influence estimates of dose from ingestion of a unit of Cesium-137 activity, and the subsequent predicted total-body dose commitment is analyzed. The analysis is based on extensive literature review and statistical comparison of parameter variability, correlation and reliability

  3. The Fukushima Health Management Survey: estimation of external doses to residents in Fukushima Prefecture

    Science.gov (United States)

    Ishikawa, Tetsuo; Yasumura, Seiji; Ozasa, Kotaro; Kobashi, Gen; Yasuda, Hiroshi; Miyazaki, Makoto; Akahane, Keiichi; Yonai, Shunsuke; Ohtsuru, Akira; Sakai, Akira; Sakata, Ritsu; Kamiya, Kenji; Abe, Masafumi

    2015-08-01

    The Fukushima Health Management Survey (including the Basic Survey for external dose estimation and four detailed surveys) was launched after the Fukushima Dai-ichi Nuclear Power Plant accident. The Basic Survey consists of a questionnaire that asks Fukushima Prefecture residents about their behavior in the first four months after the accident; and responses to the questionnaire have been returned from many residents. The individual external doses are estimated by using digitized behavior data and a computer program that included daily gamma ray dose rate maps drawn after the accident. The individual external doses of 421,394 residents for the first four months (excluding radiation workers) had a distribution as follows: 62.0%, <1 mSv 94.0%, <2 mSv 99.4%, <3 mSv. The arithmetic mean and maximum for the individual external doses were 0.8 and 25 mSv, respectively. While most dose estimation studies were based on typical scenarios of evacuation and time spent inside/outside, the Basic Survey estimated doses considering individually different personal behaviors. Thus, doses for some individuals who did not follow typical scenarios could be revealed. Even considering such extreme cases, the estimated external doses were generally low and no discernible increased incidence of radiation-related health effects is expected.

  4. Progress in estimation of dose due to the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    The magnitude of dose due to the Fukushima Daiichi Nuclear Power Plant accident was revealed by the UNSCEAR 2013 report published in April 2014. In the report, effective doses and thyroid doses were estimated for 1-year-old infants and 10-year-old children as well as adults. The UNSCEAR Committee formally agreed to rely principally on data available and literature published before the end of September 2012. However, studies on dose estimation have been conducted after that. Then, recent papers and activities of 'Fukushima Health Management Survey' are presented. In relation to this, the effective dose estimated by the UNSCEAR report was compared with the estimation by another method (extrapolation from the result of Fukushima Health Management Survey with data on individual dose measurement using personal dosimeters). As a result, they were generally consistent each other. The UNSCEAR report states, it is likely that some overestimation has been introduced generally by the methodology used by the Committee. In the case of internal dose, direct measurements of the radioactive content of the thyroid indicated doses being lower than those estimated by the Committee, by a factor of about 3 to 5. Thus, studies on reconstructing a more realistic dose for residents are still needed. (author)

  5. Rat skin carcinogenesis as a basis for estimating risks at low doses and dose rates of various types of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Burns, F. J.; Vanderlaan, M.; Strickland, P.; Albert, R. E.

    1976-01-01

    The recovery rate, age dependence and latent period for tumor induction in rat skin were measured for single and split doses of radiation, and the data were analyzed in terms of a general model in an attempt to estimate the expected tumor response for various types of radiation given at low dose rates for long periods of time. The dorsal skin of male rats was exposed to electrons, x rays, or protons in either single or split doses for several doses and the tumor responses were compared during 80 weeks of observation. A two stage model incorporating a reversible or recoverable mode was developed and various parameters in the model, including recovery rate, dose-response coefficients, and indices of age sensitivity, were evaluated experimentally. The measured parameters were then utilized to calculate expected tumor responses for exposure periods extending for duration of life. The calculations indicated that low dose rates could be markedly (/sup 1///sub 100/ to /sup 1///sub 1000/) less effective in producing tumors than the same dose given in a short or acute exposure, although the magnitude of the reduction in effectiveness declines as the dose declines.

  6. Estimation of eye absorbed doses in head & neck radiotherapy practices using thermoluminescent detectors

    Directory of Open Access Journals (Sweden)

    Gh Bagheri

    2011-09-01

    Full Text Available  Determination of eye absorbed dose during head & neck radiotherapy is essential to estimate the risk of cataract. Dose measurements were made in 20 head & neck cancer patients undergoing 60Co radiotherapy using LiF(MCP thermoluminescent dosimeters. Head & neck cancer radiotherapy was delivered by fields using SAD & SSD techniques. For each patient, 3 TLD chips were placed on each eye. Head & neck dose was about 700-6000 cGy in 8-28 equal fractions. The range of eye dose is estimated to be (3.49-639.1 mGy with a mean of maximum dose (98.114 mGy, which is about 3 % of head & neck dose. Maximum eye dose was observed for distsnces of about 3 cm from edge of the field to eye.

  7. Effects of exposure imprecision on estimation of the benchmark dose

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Esben; Keiding, Niels; Grandjean, Philippe

    2004-01-01

    , then the benchmark approach produces results that are biased toward higher and less protective levels. It is therefore important to take exposure measurement error into account when calculating benchmark doses. Methods that allow this adjustment are described and illustrated in data from an epidemiological study......In regression analysis failure to adjust for imprecision in the exposure variable is likely to lead to underestimation of the exposure effect. However, the consequences of exposure error for determination of safe doses of toxic substances have so far not received much attention. The benchmark...... approach is one of the most widely used methods for development of exposure limits. An important advantage of this approach is that it can be applied to observational data. However, in this type of data, exposure markers are seldom measured without error. It is shown that, if the exposure error is ignored...

  8. Preliminary dose estimations for a lead fast reactor

    International Nuclear Information System (INIS)

    As specified in the IAEA Safety Standards, the important sources of radiation and contamination against which protection for site personnel, the public and the environment has to be provided should be described and evaluated during the design stage of the reactor. Some of the main radiation sources during normal operation of the ELSY (European Lead Cooled System) reactor are analyzed and their contributions to the doses in few critical points from personnel radioprotection point of view are presented in the paper. Preliminary dose contributions due to lead coolant activation, due to stainless steel impurities removed by the coolant from the Internals (by corrosion/erosion) and due to the activated air flowing through the reactor vessel cooling system are also presented. The isotope inventories carried out for the analyzed reactor components could be also subsequently used in the radioprotection evaluations or in waste characterization and disposal. (authors)

  9. Effective dose estimates for cone beam computed tomography in interventional radiology

    International Nuclear Information System (INIS)

    To compare radiation doses in cone beam computed tomography (CBCT) with those of multi-detector computed tomography (MDCT) using manufacturers' standard protocols. Dose-levels in head and abdominal imaging were evaluated using a dosimetric phantom. Effective dose estimates were performed by placing thermoluminescent dosimeters in the phantom. Selected protocols for two CBCT systems and comparable protocols for one MDCT system were evaluated. Organ doses were measured and effective doses derived by applying the International Commission on Radiological Protection 2007 tissue weighting factors. Effective doses estimated for the head protocol were 4.4 and 5.4 mSv for the two CBCT systems respectively and 4.3 mSv for MDCT. Eye doses for one CBCT system and MDCT were comparable (173.6 and 148.4 mGy respectively) but significantly higher compared with the second CBCT (44.6 mGy). Two abdominal protocols were evaluated for each system; the effective doses estimated were 15.0 and 18.6 mSv, 25.4 and 37.0 mSv, and 9.8 and 13.5 mSv, respectively, for each of the CBCT and MDCT systems. The study demonstrated comparable dose-levels for CBCT and MDCT systems in head studies, but higher dose levels for CBCT in abdominal studies. There was a significant difference in eye doses observed between the CBCT systems. (orig.)

  10. Irradiation in helical scanner: doses estimation, parameters choice; Irradiation en scanner helicoidal: estimation des doses, choix des parametres

    Energy Technology Data Exchange (ETDEWEB)

    Cordoliani, Y.S.; Boyer, B.; Jouan, E.; Beauvais, H

    2001-07-01

    The new generation of helical scanners improves the diagnosis abilities and the service done to the patients. The rational use allows to give the patients a ratio benefit/risk far better than the almost medical examinations. It is particularly true for over sixty years old aged people, that have a null genetic risk and a practically null carcinogen risk; However, for young adults and children, it is necessary to banish any useless irradiation and limit exposure to the strict necessary for the diagnosis. It is necessary to develop a radiation protection culture, possible by the radiation doses index display and doses benchmarks knowledge. (N.C.)

  11. Experimental estimates of peak skin dose and its relationship to the CT dose index using the CTDI head phantom

    International Nuclear Information System (INIS)

    A straightforward method is presented to estimate peak skin doses (PSDs) delivered by computed tomography (CT) scanners. The measured PSD values are related to the well-known volume CT dose index (CTDIvol), displayed on the console of CT scanners. PSD measurement estimates were obtained, in four CT units, by placing radiochromic film on the surface of a CTDI head phantom. Six different X-ray tube currents including the maximum allowed value were used to irradiate the phantom. PSD and CTDIvol were independently measured and later related to the CTDIvol value displayed on the console. A scanner-specific relationship was found between the measured PSD and the associated CTDIvol displayed on the console. The measured PSD values varied between 27 and 136 mGy among all scanners when the routine head scan parameters were used. The results of this work allow relating the widely used CTDIvol to an actual radiation dose delivered to the skin of a patient. (authors)

  12. Dosimetric Aspects of Personnel Skin Contamination by Radionuclides - Estimate of a Skin Dose, Monitoring and Interpretation of Results

    International Nuclear Information System (INIS)

    Full text: On the basis of a critical comparison of literary data, tables are compiled of beta and gamma dose rate in mSvh-1 (kBqcm-1) to the basal layer of the skin at 0.07 mm depth from contamination by 75 radionuclides unsealed sources; radioactive substances are assumed to reside on the skin surface. The residence time needed for the estimate of the skin dose is calculated assuming that a residual activity per unit area of any radionuclide on the skin, which could not be removed by the repeated careful decontamination, is supposed to be eliminated with the biological half-life of 116 h as a consequence of the natural sloughing off of the skin. Radionuclides are divided into five groups according to the dose estimate in mSv (kBqcm-2): ≥250 (e.g. 32P, 89Sr, 137Cs/137mBa), 100-250 (e.g. 90Y, 131I, 186Re), 10-100 (e.g. 35S, 67Ga, 200Tl), 1-10 (e.g. 18F, 51Cr, 99mTc), ≤1 (e.g. 63Ni, 144Pr, 238U). If it is possible, doses can be determined more precisely by measuring the effective half-life of the residual activity on the contaminated area. Our dose estimates are approximately valid on the condition that, after decontamination, residual activity of radionuclides persists predominantly in the superficial layers of epidermis. This and further uncertainties connected with the dose assessment are discussed. Our tables can help to determine easily rough values of doses to personnel in contamination incidents and to interpret them in relation to regulatory derived limits. This work was supported by State Office for Nuclear Safety in Prague. (author)

  13. Estimation and significance of patient doses from diagnostic X ray practices in India

    International Nuclear Information System (INIS)

    Population exposure resulting from diagnostic X ray examinations is quite considerable. This exposure of the population of India was estimated from the data collected about the number of examinations per 1000 persons per year, the doses measured at the entrance surface in diagnostic examinations, conversion factors measured and organ doses estimated therefrom. The 'per caput' effective dose equivalent from diagnostic radiology is estimated to be 0.021 mSv per year. Even though this is low compared to the values reported for developed countries there is good scope for its reduction by properly optimising the X ray procedures and by ensuring Quality Assurance in diagnostic radiology

  14. The impact of different dose response parameters on biologically optimized IMRT in breast cancer

    Science.gov (United States)

    Costa Ferreira, Brigida; Mavroidis, Panayiotis; Adamus-Górka, Magdalena; Svensson, Roger; Lind, Bengt K.

    2008-05-01

    The full potential of biologically optimized radiation therapy can only be maximized with the prediction of individual patient radiosensitivity prior to treatment. Unfortunately, the available biological parameters, derived from clinical trials, reflect an average radiosensitivity of the examined populations. In the present study, a breast cancer patient of stage I II with positive lymph nodes was chosen in order to analyse the effect of the variation of individual radiosensitivity on the optimal dose distribution. Thus, deviations from the average biological parameters, describing tumour, heart and lung response, were introduced covering the range of patient radiosensitivity reported in the literature. Two treatment configurations of three and seven biologically optimized intensity-modulated beams were employed. The different dose distributions were analysed using biological and physical parameters such as the complication-free tumour control probability (P+), the biologically effective uniform dose (\\bar{\\bar{D}} ), dose volume histograms, mean doses, standard deviations, maximum and minimum doses. In the three-beam plan, the difference in P+ between the optimal dose distribution (when the individual patient radiosensitivity is known) and the reference dose distribution, which is optimal for the average patient biology, ranges up to 13.9% when varying the radiosensitivity of the target volume, up to 0.9% when varying the radiosensitivity of the heart and up to 1.3% when varying the radiosensitivity of the lung. Similarly, in the seven-beam plan, the differences in P+ are up to 13.1% for the target, up to 1.6% for the heart and up to 0.9% for the left lung. When the radiosensitivity of the most important tissues in breast cancer radiation therapy was simultaneously changed, the maximum gain in outcome was as high as 7.7%. The impact of the dose response uncertainties on the treatment outcome was clinically insignificant for the majority of the simulated patients

  15. The impact of different dose-response parameters on biologically optimized IMRT in breast cancer

    International Nuclear Information System (INIS)

    The full potential of biologically optimized radiation therapy can only be maximized with the prediction of individual patient radiosensitivity prior to treatment. Unfortunately, the available biological parameters, derived from clinical trials, reflect an average radiosensitivity of the examined populations. In the present study, a breast cancer patient of stage I-II with positive lymph nodes was chosen in order to analyse the effect of the variation of individual radiosensitivity on the optimal dose distribution. Thus, deviations from the average biological parameters, describing tumour, heart and lung response, were introduced covering the range of patient radiosensitivity reported in the literature. Two treatment configurations of three and seven biologically optimized intensity-modulated beams were employed. The different dose distributions were analysed using biological and physical parameters such as the complication-free tumour control probability (P+), the biologically effective uniform dose, dose volume histograms, mean doses, standard deviations, maximum and minimum doses. In the three-beam plan, the difference in P+ between the optimal dose distribution (when the individual patient radiosensitivity is known) and the reference dose distribution, which is optimal for the average patient biology, ranges up to 13.9% when varying the radiosensitivity of the target volume, up to 0.9% when varying the radiosensitivity of the heart and up to 1.3% when varying the radiosensitivity of the lung. Similarly, in the seven-beam plan, the differences in P+ are up to 13.1% for the target, up to 1.6% for the heart and up to 0.9% for the left lung. When the radiosensitivity of the most important tissues in breast cancer radiation therapy was simultaneously changed, the maximum gain in outcome was as high as 7.7%. The impact of the dose-response uncertainties on the treatment outcome was clinically insignificant for the majority of the simulated patients. However, the jump

  16. Importance of pre-treatment radiation absorbed dose estimation for radioimmunotherapy of non-Hodgkin's lymphoma

    International Nuclear Information System (INIS)

    Non-Hodgkin's lymphoma I-131 radioimmunotherapy data were analyzed to determine whether a predictive relationship exists between radiation absorbed doses calculated from biodistribution studies and doses derived from patient size. Radioactivity treatment administrations scaled to patient size (MBq/kg or MBq/m2) or fixed MBq doses do not produce consistent radiation absorbed dose to critical organs. Treatment trials that do not provide dose estimates for critical normal organs are less likely to succeed in identifying a clinical role for radioimmunotherapy

  17. Accuracy of patient specific organ-dose estimates obtained using an automated image segmentation algorithm

    Science.gov (United States)

    Gilat-Schmidt, Taly; Wang, Adam; Coradi, Thomas; Haas, Benjamin; Star-Lack, Josh

    2016-03-01

    The overall goal of this work is to develop a rapid, accurate and fully automated software tool to estimate patient-specific organ doses from computed tomography (CT) scans using a deterministic Boltzmann Transport Equation solver and automated CT segmentation algorithms. This work quantified the accuracy of organ dose estimates obtained by an automated segmentation algorithm. The investigated algorithm uses a combination of feature-based and atlas-based methods. A multiatlas approach was also investigated. We hypothesize that the auto-segmentation algorithm is sufficiently accurate to provide organ dose estimates since random errors at the organ boundaries will average out when computing the total organ dose. To test this hypothesis, twenty head-neck CT scans were expertly segmented into nine regions. A leave-one-out validation study was performed, where every case was automatically segmented with each of the remaining cases used as the expert atlas, resulting in nineteen automated segmentations for each of the twenty datasets. The segmented regions were applied to gold-standard Monte Carlo dose maps to estimate mean and peak organ doses. The results demonstrated that the fully automated segmentation algorithm estimated the mean organ dose to within 10% of the expert segmentation for regions other than the spinal canal, with median error for each organ region below 2%. In the spinal canal region, the median error was 7% across all data sets and atlases, with a maximum error of 20%. The error in peak organ dose was below 10% for all regions, with a median error below 4% for all organ regions. The multiple-case atlas reduced the variation in the dose estimates and additional improvements may be possible with more robust multi-atlas approaches. Overall, the results support potential feasibility of an automated segmentation algorithm to provide accurate organ dose estimates.

  18. Effective dose and organ doses estimation taking tube current modulation into account with a commercial software package

    International Nuclear Information System (INIS)

    To evaluate the effect of including tube current modulation (TCM) versus using the average mAs in estimating organ and effective dose (E) using commercial software. Forty adult patients (24 females, 16 males) with normal BMI underwent chest/abdomen computed tomography (CT) performed with TCM at 120 kVp, reference mAs of 110 (chest) and 200 (abdomen). Doses to fully irradiated organs (breasts, lungs, stomach, liver and ovaries) and E were calculated using two versions of a dosimetry software: v.2.0, which uses the average mAs, and v.2.2, which accounts for TCM by implementing a gender-specific mAs profile. Student's t-test was used to assess statistically significant differences between organ doses calculated with the two versions. A statistically significant difference (p < 0.001) was found for E on chest and abdomen CT, with E being lower by 4.2 % when TCM is considered. Similarly, organ doses were also significantly lower (p < 0.001): 13.7 % for breasts, 7.3 % for lungs, 9.1 % for the liver and 8.5 % for the stomach. Only the dose to the ovaries was higher with TCM (11.5 %). When TCM is used, for the stylized phantom, the doses to lungs, breasts, stomach and liver decreased while the dose to the ovaries increased. (orig.)

  19. Effective dose and organ doses estimation taking tube current modulation into account with a commercial software package

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rendon, X. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); Bosmans, H.; Zanca, F. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Oyen, R. [University Hospitals Leuven, Department of Radiology, Leuven (Belgium)

    2015-07-15

    To evaluate the effect of including tube current modulation (TCM) versus using the average mAs in estimating organ and effective dose (E) using commercial software. Forty adult patients (24 females, 16 males) with normal BMI underwent chest/abdomen computed tomography (CT) performed with TCM at 120 kVp, reference mAs of 110 (chest) and 200 (abdomen). Doses to fully irradiated organs (breasts, lungs, stomach, liver and ovaries) and E were calculated using two versions of a dosimetry software: v.2.0, which uses the average mAs, and v.2.2, which accounts for TCM by implementing a gender-specific mAs profile. Student's t-test was used to assess statistically significant differences between organ doses calculated with the two versions. A statistically significant difference (p < 0.001) was found for E on chest and abdomen CT, with E being lower by 4.2 % when TCM is considered. Similarly, organ doses were also significantly lower (p < 0.001): 13.7 % for breasts, 7.3 % for lungs, 9.1 % for the liver and 8.5 % for the stomach. Only the dose to the ovaries was higher with TCM (11.5 %). When TCM is used, for the stylized phantom, the doses to lungs, breasts, stomach and liver decreased while the dose to the ovaries increased. (orig.)

  20. Integrated Codes for Estimating Environmental Accumulation and Individual Dose from Past Hanford Atmospheric Releases: Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Ikenberry, T. A.; Burnett, R. A.; Napier, B. A.; Reitz, N. A.; Shipler, D. B.

    1992-02-01

    Preliminary radiation doses were estimated and reported during Phase I of the Hanford Environmental Dose Reconstruction (HEDR) Project. As the project has progressed, additional information regarding the magnitude and timing of past radioactive releases has been developed, and the general scope of the required calculations has been enhanced. The overall HEDR computational model for computing doses attributable to atmospheric releases from Hanford Site operations is called HEDRIC (Hanford Environmental Dose Reconstruction Integrated Codes). It consists of four interrelated models: source term, atmospheric transport, environmental accumulation, and individual dose. The source term and atmospheric transport models are documented elsewhere. This report describes the initial implementation of the design specifications for the environmental accumulation model and computer code, called DESCARTES (Dynamic EStimates of Concentrations and Accumulated Radionuclides in Terrestrial Environments), and the individual dose model and computer code, called CIDER (Calculation of Individual Doses from Environmental Radionuclides). The computations required of these models and the design specifications for their codes were documented in Napier et al. (1992). Revisions to the original specifications and the basis for modeling decisions are explained. This report is not the final code documentation but gives the status of the model and code development to date. Final code documentation is scheduled to be completed in FY 1994 following additional code upgrades and refinements. The user's guide included in this report describes the operation of the environmental accumulation and individual dose codes and associated pre- and post-processor programs. A programmer's guide describes the logical structure of the programs and their input and output files.

  1. SBML-PET: a Systems Biology Markup Language-based parameter estimation tool

    OpenAIRE

    Zi, Z.; Klipp, E.

    2006-01-01

    The estimation of model parameters from experimental data remains a bottleneck for a major breakthrough in systems biology. We present a Systems Biology Markup Language (SBML) based Parameter Estimation Tool (SBML-PET). The tool is designed to enable parameter estimation for biological models including signaling pathways, gene regulation networks and metabolic pathways. SBML-PET supports import and export of the models in the SBML format. It can estimate the parameters by fitting a variety of...

  2. Biological dose representation for carbon-ion radiotherapy of unconventional fractionation

    CERN Document Server

    Kanematsu, Nobuyuki

    2016-01-01

    In carbon-ion radiotherapy, single-beam delivery each day in alternate directions has been commonly practiced for operational efficiency, taking advantage of the Bragg peak and the relative biological effectiveness (RBE) for uniform dose conformation to a tumor. The treatment plans are usually evaluated with total RBE-weighted dose, which is however deficient in relevance to the biological effect in the linear-quadratic model due to its quadratic-dose term, or the dose-fractionation effect. In this study, we reformulate the extrapolated response dose (ERD), or synonymously BED, which normalizes the dose-fractionation and cell-repopulation effects as well as the RBE of treating radiation, based on inactivation of a single model cell system and a typical treating radiation in carbon-ion RT. The ERD distribution virtually represents the biological effect of the treatment regardless of radiation modality or fractionation scheme. We applied the ERD formulation to simplistic model treatments and to a preclinical su...

  3. Metastatic renal cell carcinoma: can it be palliated with radiotherapy? Do higher biologically effective doses help?

    International Nuclear Information System (INIS)

    BACKGROUND: Renal cell carcinoma (RCC) has traditionally been regarded as a 'radioresistant cancer'. Yet controversy exists as to whether dose escalation can overcome the inherent resistance of such tumors when they metastasize. Using a Tumor Dose Factor (TDF) model, Onuffrey et al. (IJROB 11:2007, 1985) showed that TDF >70 was predictive of higher palliative response rates. In contrast, Halperin et al (Cancer 51:614, 1983) could not establish a correlation between TDF equivalent dose and frequency of palliative response. Since that time, the linear quadratic model has emerged as an alternative paradigm for biologically effective dose (BED). The current project was undertaken to determine the ability of radiotherapy to palliate focally metastatic RCC and to assess whether the delivery of higher biologically effective dose was more likely to bring about complete palliative response (CR). METHODS: Between 1966 and 1995, 107 patients with renal cell metastases at 150 sites were irradiated with palliative intent. Sites irradiated included bone (n=89), soft tissue (n=16), brain (n=20), spinal cord (n=9), and pulmonary (n=16). To determine dose effectiveness, the biological effective dose (BED) was calculated according to the following formula Gy10 = Total Dose (1 + fractional dose/α-β) using an α-β of 10. The above table presents univariate comparisons. For the entire series, 94% of patients derived a palliative response after treatment with irradiation. The median duration of palliation was 4 months (range, 2-80 months). With respect to overall response, only patients with metastases to the spinal cord were significantly less likely to derive palliation in multivariate analysis (p70) and the rate of CR (p=0.03). When entered as a dichotomous variable (e.g., relative to 39 Gy 10) increasing biologically effective dose was not associated with an increased rate of complete palliation; however, when entered as a continuous variable, increasing BED was strongly

  4. The biological response of plucked human hair to low-dose radiation: a measure of individual radiosensitivity and a technique for biological dosimetry

    International Nuclear Information System (INIS)

    It is often assumed that the effects of radiation are linear with dose and that high dose effects can be extrapolated to low dose levels. However, there are a variety of mechanisms which can alter the response at low doses. The most important of these relate to induced sensitivity or induced repair mechanisms. It is therefore important that this area is studied in more depth by looking at the molecular effects and damage to cells at low doses. It is well known that there are certain rare genetic syndromes which predispose individuals to cancer, e.g. ataxia telangiectasia. It is also probable that there is a large range of sensitivity in the natural variation of individuals to the risk of radiation-induced cancer. It is proposed that radiosensitivity is studied using stimulated lymphocytes from whole blood and the technique extended to look at the effects in cell cultures established from human hair. Radiation treatment of cell cultures established from plucked human hair has been previously advocated as a non-invasive technique for non-uniform biological dosimetry and it is proposed that these techniques are adapted to the use of hair to estimate individual radiosensitivity. The aim is to establish and optimize these techniques for culturing keratinocytes from plucked human hair follicles with a view to study biological markers for the subsequent assessment of radiosensitivity. Preliminary results are promising and suggest that the technique for culturing keratinocytes from hair presents a feasible approach. Results from this primary cell culture technique and results from the comparison of the micronuclei data obtained from the cell cultures and stimulated lymphocytes will be presented. (author)

  5. Improved estimates of Ar-41 gamma dose rates around Hinkley Point power station

    International Nuclear Information System (INIS)

    The dominant source of external gamma dose rates at population centres within a few kilometres of Hinkley Point Power Station arising from operation of the station is the routine discharge of Ar-41 from the 'A' station magnox reactors. Earlier estimates of Ar-41 radiation dose rates were based upon measured discharge rates, combined with calculations using standard plume dispersion and cloud-gamma integration models. This paper presents improved dose estimates derived from environmental gamma dose rate measurements made at distances up to about 1 km from the site, minimising the degree of extrapolation introduced in estimating dose rates at locations up to a few kilometres from the site. Results from associated chemical tracer measurements and wind tunnel simulations covering distances up to about 4 km from the station are outlined. (author)

  6. Age- and sex-dependent model for estimating radioiodine dose to a normal thyroid

    International Nuclear Information System (INIS)

    This paper describes the derivation of an age- and sex-dependent model of radioiodine dosimetry in the thyroid and the application of the model to estimating the thyroid dose for each of 4215 patients who were exposed to 131I in diagnostic and therapeutic procedures. In most cases, the available data consisted of the patient's age at the time of administration, the patient's sex, the quantity of activity administered, the clinically-determined uptake of radioiodine by the thyroid, and the time after administration at which the uptake was determined. The metabolic model is of the form A(t) = K[exp(-μ1t) -exp(-μ2t)] (μCi), where μ1 = λ/sub r/ - λ/sub i//sup b/ (i = 1, 2), λ/sub r/ is the radiological decay-rate coefficient, and λ/sub i//sup b/ are biological removal rate coefficients. The values of λ/sub i//sup b/ are determined by solving a nonlinear equation that depends on assumptions about the time or maximum uptake an the eventual biological loss rate (through which age dependence enters). The value of K may then be calculated from knowledge of the uptakes at a particular time. The dosimetric S-factor (rad/μCi-day) is based on specific absorbed fractions for photons of energy ranging from 0.01 to 4.0 MeV for thyroid masses from 1.29 to 19.6 g; the functional form of the S-factor also involves the thyroid mass explicitly, through which the dependence on age and sex enters. An analysis of sensitivity of the model to uncertainties in the thyroid mass and the biological removal rate for several age groups is reported. 12 references, 5 figures, 5 tables

  7. The dose-effect relationship and the estimation of carcinogen effects of low dose of ionizing radiation

    International Nuclear Information System (INIS)

    biological effectiveness varies as a function of total dose and dose rate. In conclusion, this report raises doubts on the validity of using linear no threshold relationship for evaluating the carcinogenic risk of low doses ( under 100 mSv) and even more for very low doses( under 10 mSv). This report confirms the inappropriateness of the collective dose concept to evaluate population irradiation risks. (N.C.)

  8. ORERP (Off-Site Radiation Exposure Review Project) internal dose estimates for individuals

    International Nuclear Information System (INIS)

    A method was developed to reconstruct the internal radiation dose to off-site individuals who were exposed to fallout from nuclear weapons tests at the Nevada Test Site (NTS). By this method, committed absorbed doses can be estimated for 22 target organs of persons in four age groups and for selected organs of the fetus. Ingestion doses are calculated by combining age-group dose factors and intakes specific for age group, test event, and location as calculated by the PATHWAY food-chain model. Inhalation doses are calculated by combining age-group dose factors and breathing rates, and time-integrated air concentrations that are derived from the ORERP Air-Quality Data Base. Dose estimates are calculated for the radionuclides that contribute significantly to the total dose; these number 20 via the ingestion pathway and 46 via the inhalation pathway. Internal doses to nonspecified individuals and nonspecified fetuses are being reconstructed for each location in the ORERP Town Data Base for which exposure rates and cloud-arrival times are listed. Examples of reconstructing internal dose are presented. This method will also be adapted to reconstruct internal doses from NTS fallout to specific individuals in accordance with the person's age, past residence, life-style, and living pattern

  9. Off-Label Biologic Regimens in Psoriasis: A Systematic Review of Efficacy and Safety of Dose Escalation, Reduction, and Interrupted Biologic Therapy

    OpenAIRE

    Elizabeth A. Brezinski; Armstrong, April W.

    2012-01-01

    OBJECTIVES: While off-label dosing of biologic treatments may be necessary in selected psoriasis patients, no systematic review exists to date that synthesizes the efficacy and safety of these off-label dosing regimens. The aim of this systematic review is to evaluate efficacy and safety of off-label dosing regimens (dose escalation, dose reduction, and interrupted treatment) with etanercept, adalimumab, infliximab, ustekinumab, and alefacept for psoriasis treatment. DATA SOURCES AND STUDY SE...

  10. IDEAS: estimation of committed dose from incorporation monitoring data

    International Nuclear Information System (INIS)

    This project addresses specific problems and issues encountered in the nuclear industry, and other users of radioactive materials, in the area of internal dose assessment. The innovative aspects relate mainly to the development and application of new methods, rather than the acquisition of new knowledge or information on biokinetics and internal dosimetry. The project has three main scientific/technological objectives: (1) the creation of a database of well-documented cases, and the filling during and after the project to provide a source of basic information about internal exposure for a large number of radionuclides; (2) the development of a general philosophy for the evaluation of monitoring data from the practical experience of the scientific community; (3) the definition of general guidelines according to the general philosophy

  11. Estimating Dose Painting Effects in Radiotherapy: A Mathematical Model

    Science.gov (United States)

    López Alfonso, Juan Carlos; Jagiella, Nick; Núñez, Luis; Herrero, Miguel A.; Drasdo, Dirk

    2014-01-01

    Tumor heterogeneity is widely considered to be a determinant factor in tumor progression and in particular in its recurrence after therapy. Unfortunately, current medical techniques are unable to deduce clinically relevant information about tumor heterogeneity by means of non-invasive methods. As a consequence, when radiotherapy is used as a treatment of choice, radiation dosimetries are prescribed under the assumption that the malignancy targeted is of a homogeneous nature. In this work we discuss the effects of different radiation dose distributions on heterogeneous tumors by means of an individual cell-based model. To that end, a case is considered where two tumor cell phenotypes are present, which we assume to strongly differ in their respective cell cycle duration and radiosensitivity properties. We show herein that, as a result of such differences, the spatial distribution of the corresponding phenotypes, whence the resulting tumor heterogeneity can be predicted as growth proceeds. In particular, we show that if we start from a situation where a majority of ordinary cancer cells (CCs) and a minority of cancer stem cells (CSCs) are randomly distributed, and we assume that the length of CSC cycle is significantly longer than that of CCs, then CSCs become concentrated at an inner region as tumor grows. As a consequence we obtain that if CSCs are assumed to be more resistant to radiation than CCs, heterogeneous dosimetries can be selected to enhance tumor control by boosting radiation in the region occupied by the more radioresistant tumor cell phenotype. It is also shown that, when compared with homogeneous dose distributions as those being currently delivered in clinical practice, such heterogeneous radiation dosimetries fare always better than their homogeneous counterparts. Finally, limitations to our assumptions and their resulting clinical implications will be discussed. PMID:24586734

  12. Estimation of annual radiation dose received by some industrial workers

    International Nuclear Information System (INIS)

    Radon and its progeny in the atmosphere, soil, ground water, oil and gas deposits contributes the largest fraction of the natural radiation dose to populations, enhanced interest exhibited in tracking its concentration is thus fundamental for radiation protection. The combustion of coal in various industrial units like thermal power plants. National fertilizer plants, paper mill etc. results in the release of some natural radioactivity to the atmosphere through formation of fly ash and bottom ash or slag. This consequent increases the radioactivity in soil, water and atmosphere around thermal power plants. Keeping this in mind the measurements of radon, thoron and their progeny concentration in the environment of some industrial units has been carried out using solid state nuclear track detectors (SSNTD). The specially designed twin cup dosimeter used here consists two chambers of cylindrical geometry separated by a wall in the middle with each having length of 4.5 cm and radius of 3.1 cm. This dosimeter employs three SSNTDs out of which two detectors were placed in each chamber and a third one was placed on the outer surface of the dosimeter. One chamber is fitted with glass fiber filter so that radon and thoron both can diffuse into the chamber while in other chamber, a semi permeable membrane is used. The membrane mode measures the radon concentration alone as it can diffuse through the membrane but suppresses the thoron. The twin cup dosimeter also has a provision for bare mode enabling it to register tracks due to radon, thoron and their progeny in total. Therefore, using this dosimeter we can measure the individual concentration of radon, thoron, and their progeny at the same time. The annual effective doses received by the workers in some industrial units has been calculated. The results indicate some higher levels in coal handling and fly ash area of the plants. (author)

  13. Uncertainties in estimating heart doses from 2D-tangential breast cancer radiotherapy

    DEFF Research Database (Denmark)

    Lorenzen, Ebbe L; Brink, Carsten; Taylor, Carolyn W; Darby, Sarah C; Ewertz, Marianne

    2016-01-01

    -based planning scans for 40 patients with left-sided and 10 with right-sided breast cancer. Setup errors and organ motion were simulated using estimated uncertainties. For left-sided patients, mean heart dose was related to maximum heart distance in the medial field. RESULTS: For left-sided breast cancer, mean...... uncertainty of estimates based on individual CT-scans. For right-sided breast cancer patients, mean heart dose based on individual CT-scans was always <1Gy and maximum dose always <5Gy for all three regimens. CONCLUSIONS: The use of stored individual simulator films provides a method for estimating heart......BACKGROUND AND PURPOSE: We evaluated the accuracy of three methods of estimating radiation dose to the heart from two-dimensional tangential radiotherapy for breast cancer, as used in Denmark during 1982-2002. MATERIAL AND METHODS: Three tangential radiotherapy regimens were reconstructed using CT...

  14. Estimates of Radiation Dose Rates Near Large Diameter Sludge Containers in T Plant

    CERN Document Server

    Himes, D A

    2002-01-01

    Dose rates in T Plant canyon during the handling and storage of large diameter storage containers of K Basin sludge were estimated. A number of different geometries were considered from which most operational situations of interest can be constructed.

  15. A method of estimating conceptus doses resulting from multidetector CT examinations during all stages of gestation

    International Nuclear Information System (INIS)

    Purpose: Current methods for the estimation of conceptus dose from multidetector CT (MDCT) examinations performed on the mother provide dose data for typical protocols with a fixed scan length. However, modified low-dose imaging protocols are frequently used during pregnancy. The purpose of the current study was to develop a method for the estimation of conceptus dose from any MDCT examination of the trunk performed during all stages of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study to model the Siemens Sensation 16 and Sensation 64 MDCT scanners. Four mathematical phantoms were used, simulating women at 0, 3, 6, and 9 months of gestation. The contribution to the conceptus dose from single simulated scans was obtained at various positions across the phantoms. To investigate the effect of maternal body size and conceptus depth on conceptus dose, phantoms of different sizes were produced by adding layers of adipose tissue around the trunk of the mathematical phantoms. To verify MCNP results, conceptus dose measurements were carried out by means of three physical anthropomorphic phantoms, simulating pregnancy at 0, 3, and 6 months of gestation and thermoluminescence dosimetry (TLD) crystals. Results: The results consist of Monte Carlo-generated normalized conceptus dose coefficients for single scans across the four mathematical phantoms. These coefficients were defined as the conceptus dose contribution from a single scan divided by the CTDI free-in-air measured with identical scanning parameters. Data have been produced to take into account the effect of maternal body size and conceptus position variations on conceptus dose. Conceptus doses measured with TLD crystals showed a difference of up to 19% compared to those estimated by mathematical simulations. Conclusions: Estimation of conceptus doses from MDCT examinations of the trunk performed on pregnant patients during all stages of gestation can be made

  16. Blood residue effect on organs and its repercussion in dose estimation

    International Nuclear Information System (INIS)

    In this paper the authors use the Theory of Compartment analysis to show the effect of residual blood in the organs, which would imply overestimated doses. Based on the results obtained, it is observed the utility of Compartment Analysis whenever studies are conducted 'post-mortis' for better estimation of absorbed doses in organs and tissues

  17. Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment.

    Science.gov (United States)

    Ramola, R C; Prasad, Mukesh; Kandari, Tushar; Pant, Preeti; Bossew, Peter; Mishra, Rosaline; Tokonami, S

    2016-01-01

    The annual exposure to indoor radon, thoron and their progeny imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive measurements of indoor radon, thoron and their progeny concentrations that were carried out in Garhwal Himalaya with the aim of investigating significant health risk to the dwellers in the region. The measurements were performed using recently developed LR-115 detector based techniques. The experimentally determined values of radon, thoron and their progeny concentrations were used to estimate total annual inhalation dose and annual effective doses. The equilibrium factors for radon and thoron were also determined from the observed data. The estimated value of total annual inhalation dose was found to be 1.8 ± 0.7 mSv/y. The estimated values of the annual effective dose were found to be 1.2 ± 0.5 mSv/y and 0.5 ± 0.3 mSv/y, respectively. The estimated values of radiation doses suggest no important health risk due to exposure of radon, thoron and progeny in the study area. The contribution of indoor thoron and its progeny to total inhalation dose ranges between 13-52% with mean value of 30%. Thus thoron cannot be neglected when assessing radiation doses. PMID:27499492

  18. Equivalent dose (palaeo-dose) estimation in thermoluminescence dating using a single aliquot of poly-mineral fine grains

    International Nuclear Information System (INIS)

    A single aliquot protocol for the estimation of the natural dose in thermoluminescence dating (SATL) is presented that makes use of poly-mineral fine grains extracted from ceramic materials. The protocol is demonstrated using aliquots made from two Neolithic sherds and is compared with results from an additive dose poly-mineral technique. The results of both techniques are in close agreement and highlight the potential advantages of the new procedure, especially when sample availability is restricted, e.g. dating of small pottery fragments, or in cases of authenticity testing. (authors)

  19. Answers to questions about updated estimates of occupational radiation doses at Three Mile Island, Unit 2

    Energy Technology Data Exchange (ETDEWEB)

    1983-12-01

    The purpose of this question and answer report is to provide a clear, easy-to-understand explanation of revised radiation dose estimates which workers are likely to receive over the course of the cleanup at Three Mile Island, Unit 2, and of the possible health consequences to workers of these new estimates. We will focus primarily on occupational dose, although pertinent questions about public health and safety will also be answered.

  20. Answers to questions about updated estimates of occupational radiation doses at Three Mile Island, Unit 2

    International Nuclear Information System (INIS)

    The purpose of this question and answer report is to provide a clear, easy-to-understand explanation of revised radiation dose estimates which workers are likely to receive over the course of the cleanup at Three Mile Island, Unit 2, and of the possible health consequences to workers of these new estimates. We will focus primarily on occupational dose, although pertinent questions about public health and safety will also be answered

  1. Dose estimation from food intake due to the Fukushima Daiichi nuclear power plant accident

    International Nuclear Information System (INIS)

    Since the Fukushima Daiichi nuclear power plant accident, concerns have arisen about the radiation safety of food raised at home and abroad. Therefore, many measures have been taken to address this. To evaluate the effectiveness of these measures, dose estimation due to food consumption has been attempted by various methods. In this paper, we show the results of dose estimation based on the monitoring data of radioactive materials in food published by the Ministry of Health, Labour and Welfare. The Radioactive Material Response Working Group in the Food Sanitation Subcommittee of the Pharmaceutical Affairs and Food Sanitation Council reported such dose estimation results on October 31, 2011 using monitoring data from immediately after the accident through September, 2011. Our results presented in this paper were the effective dose and thyroid equivalent dose integrated up to December 2012 from immediately after the accident. The estimated results of committed effective dose by age group derived from the radioiodine and radiocesium in food after the Fukushima Daiichi nuclear power plant accident showed the highest median value (0.19 mSv) in children 13-18 years of age. The highest 95% tile value, 0.33 mSv, was shown in the 1-6 years age range. These dose estimations from food can be useful for evaluation of radiation risk for individuals or populations and for radiation protection measures. It would also be helpful for the study of risk management of food in the future. (author)

  2. Estimation of Dose Received in Decommissioning of Phosphate Acid Factory-Petro Kimia Gresik

    International Nuclear Information System (INIS)

    The estimation of dose received in decommissioning of Phosphate Acid Factory-Petro Kimia Gresik (PAF-PKG) was carried out. The external dose estimated base on the radiation rate in each working area of zona-1, 2, 3 and 4. The internal dose estimated base on the radionuclides activity and diameter of particulate exist in each working area. The calculation of the internal dose was carried out by LUDEP 2.0 computer code. The results indicated that in the normal activity of decommissioning, the effective dose will received by the worker per year were 0.27 mSv in zona-1, 1.23 mSv in zona-2, 1.37 mSv in zona-3 and 11.85 mSv in zona-4. The internal dose received when a worse accident happens in decommissioning activity is 21.06 mSv for lung organ or 4.2 % of the dose limit for that organ. Based on the discussion above, indicated that in the decommissioning of PAF-PKG the dose received by the workers is far lower than the dose limit. (author)

  3. Assessment of internal dose from incorporated plutonium-239 by means of biological dosimetry

    International Nuclear Information System (INIS)

    Intra- and inter-chromosomal aberration frequency in Mayak P.A. nuclear workers was studied by mFISH and mBAND techniques. Intra-chromosomal aberrations in lymphocytes from the peripheral blood were found to be a bio marker of densely-ionizing radiation (alpha-particles) in workers exposed to radiation many years ago. A dependence of the frequency of intra-chromosomal aberrations in plutonium workers on absorbed dose to the red bone marrow from internal exposure to incorporated plutonium-239 was found. A preliminary 'bio dosimetry system' was developed. Its capability to estimate internal doses from incorporated plutonium-239 in plutonium production workers based on the frequency of intra-chromosomal aberrations detected in these workers was tested. Estimates of internal doses from incorporated plutonium - 239 obtained using the preliminary 'bio dosimetry system' were compared with doses calculated by a model based on measurements of plutonium excretion in urine ('Mayak Doses-2000'). Estimates of internal doses from incorporated plutonium-239 obtained using both independent techniques demonstrated a highly significant correlation (correlation coefficient, R2 = 74%). At the current research phase, the developed 'bio dosimetry system' is to be adjusted, which will allow to estimate plutonium-239 body burden with an uncertainty less than 30%. (authors)

  4. Sensitivity and uncertainty investigations for Hiroshima dose estimates and the applicability of the Little Boy mockup measurements

    International Nuclear Information System (INIS)

    This paper describes sources of uncertainty in the data used for calculating dose estimates for the Hiroshima explosion and details a methodology for systematically obtaining best estimates and reduced uncertainties for the radiation doses received

  5. Cancer risk estimates from the combined Japanese A-bomb and Hodgkin cohorts for doses relevant to radiotherapy.

    Science.gov (United States)

    Schneider, Uwe; Walsh, Linda

    2008-04-01

    Most information on the dose-response of radiation-induced cancer is derived from data on the A-bomb survivors who were exposed to gamma-rays and neutrons. Since, for radiation protection purposes, the dose span of main interest is between 0 and 1 Gy, the analysis of the A-bomb survivors is usually focused on this range. However, estimates of cancer risk for doses above 1 Gy are becoming more important for radiotherapy patients and for long-term manned missions in space research. Therefore in this work, emphasis is placed on doses relevant for radiotherapy with respect to radiation-induced solid cancer. The analysis of the A-bomb survivor's data was extended by including two extra high-dose categories (4-6 Sv and 6-13 Sv) and by an attempted combination with cancer data on patients receiving radiotherapy for Hodgkin's disease. In addition, since there are some recent indications for a high neutron dose contribution, the data were fitted separately for three different values for the relative biological effectiveness (RBE) of the neutrons (10, 35 and 100) and a variable RBE as a function of dose. The data were fitted using a linear, a linear-exponential and a plateau-dose-response relationship. Best agreement was found for the plateau model with a dose-varying RBE. It can be concluded that for doses above 1 Gy there is a tendency for a nonlinear dose-response curve. In addition, there is evidence of a neutron RBE greater than 10 for the A-bomb survivor data. Many problems and uncertainties are involved in combing these two datasets. However, since very little is currently known about the shape of dose-response relationships for radiation-induced cancer in the radiotherapy dose range, this approach could be regarded as a first attempt to acquire more information on this area. The work presented here also provides the first direct evidence that the bending over of the solid cancer excess risk dose response curve for the A-bomb survivors, generally observed above 2 Gy

  6. Use of virtual reality to estimate radiation dose rates in nuclear plants

    International Nuclear Information System (INIS)

    Operators in nuclear plants receive radiation doses during several different operation procedures. A training program capable of simulating these operation scenarios will be useful in several ways, helping the planning of operational procedures so as to reduce the doses received by workers, and to minimize operations' times. It can provide safe virtual operation training, visualization of radiation dose rates, and estimation of doses received by workers. Thus, a virtual reality application, a free game engine, has been adapted to achieve the goals of this project. Simulation results for Argonauta research reactor of Instituto de Engenharia Nuclear are shown in this paper. A database of dose rate measurements, previously performed by the radiological protection service, has been used to display the dose rate distribution in the region of interest. The application enables the user to walk in the virtual scenario, displaying at all times the dose accumulated by the avatar. (author)

  7. Low doses of ionizing radiation: Biological effects and regulatory control. Contributed papers

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency and the World Health Organization, in cooperation with the United Nations Scientific Committee on the Effects of Atomic Radiation, organized an international conference on Low Doses of Ionizing Radiation: Biological Effects and Regulatory Control, held in seville, Spain, from 17 to 21 November 1997. This technical document contains concise papers submitted to the conference

  8. Estimation of staff lens doses during interventional procedures. Comparing cardiology, neuroradiology and interventional radiology

    International Nuclear Information System (INIS)

    The purpose of this article is to estimate lens doses using over apron active personal dosemeters in interventional catheterisation laboratories (cardiology IC, neuroradiology IN and radiology IR) and to investigate correlations between occupational lens doses and patient doses. Active electronic personal dosemeters placed over the lead apron were used on a sample of 204 IC procedures, 274 IN and 220 IR (all performed at the same university hospital). Patient dose values (kerma area product) were also recorded to evaluate correlations with occupational doses. Operators used the ceiling-suspended screen in most cases. The median and third quartile values of equivalent dose Hp(10) per procedure measured over the apron for IC, IN and IR resulted, respectively, in 21/67, 19/44 and 24/54 μSv. Patient dose values (median/third quartile) were 75/128, 83/176 and 61/159 Gy cm2, respectively. The median ratios for dosemeters worn over the apron by operators ( protected by the ceiling-suspended screen) and patient doses were 0.36; 0.21 and 0.46 μSv Gy-1 cm-2, respectively. With the conservative approach used (lens doses estimated from the over apron chest dosemeter) we came to the conclusion that more than 800 procedures y-1 and per operator were necessary to reach the new lens dose limit for the three interventional specialties. (authors)

  9. Estimation of staff lens doses during interventional procedures. Comparing cardiology, neuroradiology and interventional radiology.

    Science.gov (United States)

    Vano, E; Sanchez, R M; Fernandez, J M

    2015-07-01

    The purpose of this article is to estimate lens doses using over apron active personal dosemeters in interventional catheterisation laboratories (cardiology IC, neuroradiology IN and radiology IR) and to investigate correlations between occupational lens doses and patient doses. Active electronic personal dosemeters placed over the lead apron were used on a sample of 204 IC procedures, 274 IN and 220 IR (all performed at the same university hospital). Patient dose values (kerma area product) were also recorded to evaluate correlations with occupational doses. Operators used the ceiling-suspended screen in most cases. The median and third quartile values of equivalent dose Hp(10) per procedure measured over the apron for IC, IN and IR resulted, respectively, in 21/67, 19/44 and 24/54 µSv. Patient dose values (median/third quartile) were 75/128, 83/176 and 61/159 Gy cm(2), respectively. The median ratios for dosemeters worn over the apron by operators (protected by the ceiling-suspended screen) and patient doses were 0.36; 0.21 and 0.46 µSv Gy(-1) cm(-2), respectively. With the conservative approach used (lens doses estimated from the over apron chest dosemeter) we came to the conclusion that more than 800 procedures y(-1) and per operator were necessary to reach the new lens dose limit for the three interventional specialties. PMID:25848117

  10. Estimation of the absorbed dose in gamma irradiated food containing bone by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    The use of electron spin resonance (ESR) spectroscopy to accurately evaluate the absorbed dose to radiationprocessed bones (and thus meats) is examined. The exposure of foodstuffs containing bone to a dose of ionizing radiation results in the formation of long lived free radicals which give rise to characteristics ESR signals. The yield of radicals was found to be proportional to absorbed dose. Additive re-irradiation of previously irradiated bone was used to estimate the absorbed dose in the irradiated chicken bone. Simple non-linear rational equation was found to fit to the data and yields good dose estimates for irradiated bone in the range of doses (1.0 - 5.0 kGy). Decay of the ESR signal intensity was monitored at different dose levels (2.0 and 7.0 kGy) up to 22 days. The absorbed dose in irradiated chicken (2.Om 3.0 and 6.0 kGy) was assessed at 2, 6 and 12 days after irradiation. Relatively good results were obtained when measurements were made within the following days (up to 12 days) after irradiation. The ability of the dose additive method to provide accurate dose assessments is tested here

  11. Dose estimation in postoperative keloid irradiation with special consideration of ovarian dose

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, W.F.O.; Hohenberg, G.; Handl-Zeller, L. (Vienna Univ. (Austria). Klinik fuer Strahlentherapie und Strahlenbiologie)

    1991-09-01

    For a long time now, surgery followed irradiation has been the preferred therapy in the treatment of keloids. Radiation can be administered by means of X-rays (energy level {<=} 100 KV), electrons (energy level {<=} 5 MeV) or {sup 191}Ir-wires. The choice of one of these methods depends on the availability of suitable facilities within a short period of time (<24 hours postoperatively), and the possibility of adapting the irradiation field quickly and easily to the scar. A further criterion is the dose received by underlying organs possibly, especially the ovaries of women of child-bearing age. It consists of primary and secondary (scattered) parts of radiation and was measured in two standard field sizes for the various types of radiation so as to allow a rapid evaluation. Apart from the types of radiation mentioned above, such measurements were also carried out for {sup 125}I seeds. With a field size of 20x1.5 cm{sup 2} and a surface dose of 10 Gy, ovaries at a depth of 10 cm in the central beam will receive a dose of between <1 mGy in electron therapy to around 1 Gy in X-ray therapy (100 KV). (orig.).

  12. Slide Rule for Rapid Response Estimation of Radiological Dose from Criticality Accidents

    International Nuclear Information System (INIS)

    This paper describes a functional slide rule that provides a readily usable in-hand method for estimating nuclear criticality accident information from sliding graphs, thereby permitting (1) the rapid estimation of pertinent criticality accident information without laborious or sophisticated calculations in a nuclear criticality emergency situation, (2) the appraisal of potential fission yields and external personnel radiation exposures for facility safety analyses, and (3) a technical basis for emergency preparedness and training programs at nonreactor nuclear facilities. The slide rule permits the estimation of neutron and gamma dose rates and integrated doses based upon estimated fission yields, distance from the fission source, and time-after criticality accidents for five different critical systems. Another sliding graph permits the estimation of critical solution fission yields based upon fissile material concentration, critical vessel geometry, and solution addition rate. Another graph provides neutron and gamma dose-reduction factors for water, steel, and concrete shields

  13. Arsenic, mode of action at biologically plausible low doses: What are the implications for low dose cancer risk?

    International Nuclear Information System (INIS)

    Arsenic is an established human carcinogen. However, there has been much controversy about the shape of the arsenic response curve, particularly at low doses. This controversy has been exacerbated by the fact that the mechanism(s) of arsenic carcinogenesis are still unclear and because there are few satisfactory animal models for arsenic-induced carcinogenesis. Recent epidemiological studies have shown that the relative risk for cancer among populations exposed to ≤60 ppb As in their drinking water is often lower than the risk for the unexposed control population. We have found that treatment of human keratinocyte and fibroblast cells with 0.1 to 1 μM arsenite (AsIII) also produces a low dose protective effect against oxidative stress and DNA damage. This response includes increased transcription, protein levels and enzyme activity of several base excision repair genes, including DNA polymerase β and DNA ligase I. At higher concentrations (> 10 μM), As induces down-regulation of DNA repair, oxidative DNA damage and apoptosis. This low dose adaptive (protective) response by a toxic agent is known as hormesis and is characteristic of many agents that induce oxidative stress. A mechanistic model for arsenic carcinogenesis based on these data would predict that the low dose risk for carcinogenesis should be sub-linear. The threshold dose where toxicity outweighs protection is hard to predict based on in vitro dose response data, but might be estimated if one could determine the form (metabolite) and concentration of arsenic responsible for changes in gene regulation in the target tissues

  14. Dose estimates for the heavy concrete ratchet wall configuration

    International Nuclear Information System (INIS)

    During the 1987 meeting of the APS User's Subcommittee on Conventional Facilities, we were urged to study changes in shield-wall geometry for the storage ring so as to provide an increased portion of the photon beam outside that shield. The shield-wall position, with respect to the source point, is a geometric function of the thickness of the wall, the clearance between the photon beam inside the wall (front-end area), and the corresponding clearance outside the wall. The relationship of any of these three dimensions and the resulting movement of the ratchet portion of the wall (and thus the portion of the beam line outside the shield) is about one-to-eleven, so that for each inch given up in clearance or wall thickness, eleven inches of beam-line length is exposed. Unfortunately, the two clearances were already considered minimal, and the shield-wall thickness determines the radiation dose received on the operating floor and is not really a open-quote free parameterclose quotes. The first change made in geometry was to consider the use of heavy concrete for the wall construction. (The inner wall and roof are still considered to be normal concrete.) A thickness of 0.56 m was chosen, since that provided the same shield quality as the former 0.8-m normal concrete wall. The ratchet thickness itself was left at 0.8 m for several reasons: the wall encloses a lead/concrete plug of 0.8 m total length; there is only a one-to-one relationship between this dimension and the beam-line length exposed; and the 0.8-m length will prove to be important in consideration of the forward-angle bremsstrahlung radiation

  15. On the uncertainties in effective dose estimates of adult CT head scans

    International Nuclear Information System (INIS)

    Estimates of the effective dose to adult patients from computed tomography (CT) head scanning can be calculated using a number of different methods. These estimates can be used for a variety of purposes, such as improving scanning protocols, comparing different CT imaging centers, and weighing the benefits of the scan against the risk of radiation-induced cancer. The question arises: What is the uncertainty in these effective dose estimates? This study calculates the uncertainty of effective dose estimates produced by three computer programs (CT-EXPO, CTDosimetry, and ImpactDose) and one method that makes use of dose-length product (DLP) values. Uncertainties were calculated in accordance with an internationally recognized uncertainty analysis guide. For each of the four methods, the smallest and largest overall uncertainties (stated at the 95% confidence interval) were: 20%-31% (CT-EXPO), 15%-28% (CTDosimetry), 20%-36% (ImpactDose), and 22%-32% (DLP), respectively. The overall uncertainties for each method vary due to differences in the uncertainties of factors used in each method. The smallest uncertainties apply when the CT dose index for the scanner has been measured using a calibrated pencil ionization chamber

  16. A practical and transferable methodology for dose estimation in irradiated spices, based on thermoluminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    D' Oca, M.C. [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, Via M.Cipolla 74d, 90123 Palermo (Italy)], E-mail: cristinadoca@libero.it; Bartolotta, A.; Cammilleri, C.; Giuffrida, S. [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, Via M.Cipolla 74d, 90123 Palermo (Italy); Parlato, A. [Dipartimento di Ingegneria Nucleare, Universita di Palermo, Viale delle Scienze, Edificio 6, 90100 Palermo (Italy); Di Stefano, V. [Dipartimento di Chimica e Tecnologie Farmaceutiche, Universita di Palermo, Via Archirafi 32, 90123 Palermo (Italy)

    2010-04-15

    The thermoluminescence technique is recommended by the European Committee for Standardization for the detection of irradiated food containing silicates as contaminants. In this work, the applicability of the thermoluminescence technique as a quantitative method to assess the original dose in irradiated oregano was studied; the additive-dose method was used, with reirradiation doses up to 600 Gy. The proposed new procedure allows to clearly discriminate irradiated from unirradiated samples, even after one year storage, and it gives an acceptable estimation of the original dose; the overall modified procedure requires only one day to be completed.

  17. Doses due to tritium releases by NET - data base and relevant parameters on biological tritium behaviour

    International Nuclear Information System (INIS)

    This study gives an overview on the current knowledge about the behaviour of tritium in plants and in food chains in order to evaluate the ingestion pathway modelling of existing computer codes for dose estimations. The tritium uptake and retention by plants standing at the beginning of the food chains is described. The different chemical forms of tritium, which may be released into the atmosphere (HT, HTO and tritiated organics), and incorporation of tritium into organic material of plants are considered. Uptake and metabolism of tritiated compounds in animals and man are reviewed with particular respect to organically bound tritium and its significance for dose estimations. Some basic remarks on tritium toxicity are also included. Furthermore, a choice of computer codes for dose estimations due to chronic or accidental tritium releases has been compared with respect to the ingestion pathway. (orig.)

  18. Estimation of the effective doses for interventional employees in three common interventional diagnosis and treatment procedures

    International Nuclear Information System (INIS)

    Objective: To study and estimate the effective dose of interventional employees in the common cerebral vascular, cardiovascular and liver interventional diagnosis and treatment. Methods: The absorbed doses of tissue or organ of anthropomorphic phantom in these three procedures were estimated by the anthropomorphic phantom experiment. The effective doses were calculated by the tissue weight factor which was given by International Commission on Radiological Protection publication 103. Results: The effective doses to high, medium and low group were 24.0, 9.7, 6.8 μSv for cerebral vascular interventional diagnosis and treatment, and 36.3, 29.3, 17.8 μSv for cardiovascular interventional diagnosis and treatment, and 23.9, 11.3, 5.5 μ Sv for liver interventional diagnosis and treatment, respectively. Conclusions: The effective doses of high, medium and low group of interventional employees in cardiovascular interventional procedure are higher than those of cerebral vascular and liver interventional procedures. (authors)

  19. Estimation of photon dose generated by a short pulse high power laser

    International Nuclear Information System (INIS)

    The authors obtain a new equation to estimate the forward component of a photon dose generated through the interaction between a target and a short pulse high power laser. As the equation is quite simple, it is useful for calculating the photon dose. The equation shows that the photon dose is proportional to the electron temperature in the range >3 MeV and proportional to the square of the electron temperature in the range <3 MeV. The dose estimated with this method is roughly consistent with the result of Monte Carlo simulation. With some assumptions and corrections, it can reproduce experimental results obtained and the dose result calculated at other laboratories. (authors)

  20. Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project: Draft

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.M.; Bates, D.J.; Marsh, T.L.

    1993-03-01

    This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

  1. Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.M.; Bates, D.J.; Marsh, T.L.

    1993-07-01

    This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

  2. Estimation of effective dose at thyroid cancer patients treated with I131

    International Nuclear Information System (INIS)

    Full text of publication follows. Radioiodine therapy for thyroid cancer patients and hyperthyroid patients at the Institute of Pathophysiology and nuclear medicine is performed in a form of capsules. During the oral application it is reasonable to presume that 15 minutes in stomach is long enough to make additional exposure to stomach as well to other organs nearby. It is almost impossible to perform direct measurements to estimate internal doses of organs, so it is rather recommended to estimate the dose by calculation. Absorbed energy per unit transformation in stomach and surrounding organs has been calculated. The dose equivalents in several internal organs have been calculated in aim to determine the effective doses using appropriate tissue weighting factor values. The MCNP-4b model was used for this calculation. The phantom model was created using three major sections: - an elliptical cylinder representing the trunk and arms - two truncated circular cones representing the legs and feet - a circular cylinder on which sits an elliptical cylinder capped by half an ellipsoid representing the neck and head. The stomach wall is represented by the volume between two concentric ellipsoids and the contents by the volume within the inner ellipsoid. Also TLD measurements were performed over gastric region for limited time of 15 minutes. Estimated effective dose was highest in stomach 7,43*10-02 Sv. The estimated values for other organs like colon, liver, lungs, ovary and bone surface was less than the estimated effective dose of stomach. (authors)

  3. Intake estimation and dose assessment of 90Sr, 137Cs around QNPP base

    International Nuclear Information System (INIS)

    90Sr and 137Cs are important radionuclides in environmental investigation related to nuclear power stations. A mode of intake estimation and dose assessment via various food chains is made in this paper. Based on daily food consumption and dietary composition for Chinese reference man and for man of Zhejiang province and the concentration of 137Cs and 90Sr around QNPP Base, the intake estimation and dose of 90Sr and 137Cs around QNPP Base are calculated. It shows that the main food sources of intake of 90Sr and 137Cs are rice,vegetable and aquatic product. Also the public average annual committed effective dose of 90Sr(2.5 μSv)is obviously higher than the contribution of dose of the 137Cs(0.36 μSv). A practical estimation method was made by taking QNPP Base as an example in this paper, while no background change occurs after its commercial operation. (authors)

  4. Effect of tube current modulation for dose estimation using a simulation tool on body CT examination

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the effect of tube current modulation for dose estimation of a body computed tomography (CT) examination using a simulation tool. The authors also compared longitudinal variations in tube current values between iterative reconstruction (IR) and filtered back-projection (FBP) reconstruction algorithms. One hundred patients underwent body CT examinations. The tube current values around 10 organ regions were recorded longitudinally from tube current information. The organ and effective doses were simulated by average tube current values and longitudinal modulated tube current values. The organ doses for the bladder and breast estimated by longitudinal modulated tube current values were 20 % higher and 25 % lower than those estimated using the average tube current values, respectively. The differences in effective doses were small (mean, 0.7 mSv). The longitudinal variations in tube current values were almost the same for the IR and FBP algorithms. (authors)

  5. Estimation of terrestrial air-absorbed dose rate from the data of regional geochemistry database

    International Nuclear Information System (INIS)

    This paper presents an estimation of air-absorbed dose rate from the data of K2O, U and Th content from Chinese regional geochemical database. A total of 421 group original data of combined samples in Zhongshan City (ZSC), Guangdong Province and south China were extracted from the national geochemical database. Estimated average value of air-absorbed dose rate is 139.4 nGy h-1 in the granite area and 73.7 nGy h-1 in the sedimentary area. The level of air-absorbed dose rate is closely related with the surface lithology. Estimated mean air-absorbed dose rate approximates to the measured average value by a portable plastic scintillator dosemeter in Zhuhai City were bordered with ZSC. The results show that the pre-evaluation of ionizing radiation level using regional geochemical data is feasible. (author)

  6. An estimate of the doubling dose of ionizing radiation for humans

    International Nuclear Information System (INIS)

    All accumulated data on the children of Hiroshima and Nagasaki survivors have been analyzed employing the revised procedures for estimating gonadal radiation exposures that became effective in 1986. The basic statistical procedure employed has been to obtain a linear regression of indicator on the combined gonadal exposures of the parents. There is no statistically significant regression of indicator on dose for any of the indicators; however, it is accepted that some mutations were produced in the survivors of the bombings. The implications of the data for the genetic doubling dose of radiation for humans have been explored. The appropriate dose rate factor to be applied in extrapolating to the effect of chronic radiation is 2. This leads to a doubling dose estimate for the chronic irradiation of humans of between 3.4 and 4.5 Sv. The error is large but indeterminate, but the estimate is based on conservative assumptions. (3 tabs.)

  7. Estimation of the Dose of Radiation Received by Patient and Physician During a Videofluoroscopic Swallowing Study.

    Science.gov (United States)

    Morishima, Yoshiaki; Chida, Koichi; Watanabe, Hiroshi

    2016-08-01

    Videofluoroscopic swallowing study (VFSS) is considered the standard diagnostic imaging technique to investigate swallowing disorders and dysphagia. Few studies have been reported concerning the dose of radiation a patient receives and the scattering radiation dose received by a physician during VFSS. In this study, we investigated the dose of radiation (entrance skin dose, ESD) estimated to be received by a patient during VFSS using a human phantom (via a skin-dose monitor sensor placed on the neck of the human phantom). We also investigated the effective dose (ED) and dose equivalent (DE) received by a physician (wearing two personal dosimeters) during an actual patient procedure. One dosimeter (whole body) was worn under a lead apron at the chest, and the other (specially placed to measure doses received by the lens of the eye) outside the lead apron on the neck collar to monitor radiation doses in parts of the body not protected by the lead apron. The ESD for the patient was 7.8 mGy in 5 min. We estimated the average patient dose at 12.79 mGy per VFSS procedure. The physician ED and DE during VFSS were 0.9 mSv/year and 2.3 mSv/year, respectively. The dose of radiation received by the physician in this study was lower than regulatory dose limits. However, in accordance with the principle that radiation exposure should be as low as reasonably achievable, every effort should be made (e.g., wearing lead glasses) to reduce exposure doses. PMID:27318941

  8. Estimation of staff doses in complex radiological examinations using a Monte Carlo computer code

    International Nuclear Information System (INIS)

    The protection of medical personnel in interventional radiology is an important issue of radiological protection. The irradiation of the worker is largely non-uniform, and a large part of his body is shielded by a lead apron. The estimation of effective dose (E) under these conditions is difficult and several approaches are used to estimate effective dose involving such a protective apron. This study presents a summary from an extensive series of simulations to determine scatter-dose distribution around the patient and staff effective dose from personal dosimeter readings. The influence of different parameters (like beam energy and size, patient size, irradiated region, worker position and orientation) on the staff doses has been determined. Published algorithms that combine readings of an unshielded and a shielded dosimeter to estimate effective dose have been applied and a new algorithm, that gives more accurate dose estimates for a wide range of situations was proposed. A computational approach was used to determine the dose distribution in the worker's body. The radiation transport and energy deposition was simulated using the MCNP4B code. The human bodies of the patient and radiologist were generated with the Body Builder anthropomorphic model-generating tool. The radiologist is protected with a lead apron (0.5 mm lead equivalent in the front and 0.25 mm lead equivalent in the back and sides) and a thyroid collar (0.35 mm lead equivalent). The lower-arms of the worker were folded to simulate the arms position during clinical examinations. This realistic situation of the folded arms affects the effective dose to the worker. Depending on the worker position and orientation (and of course the beam energy), the difference can go up to 25 percent. A total of 12 Hp(10) dosimeters were positioned above and under the lead apron at the neck, chest and waist levels. Extra dosimeters for the skin dose were positioned at the forehead, the forearms and the front surface of

  9. Estimation of radionuclide ingestion: Lessons from dose reconstruction for fallout from the Nevada Test Site

    International Nuclear Information System (INIS)

    The United States conducted atmospheric testing of nuclear devices at the Nevada Test Site from 1951 through 1963. In 1979 the U.S. Department of Energy established the Off-Site Radiation Exposure Review Project to compile a data base related to health effects from nuclear testing and to reconstruct doses to public residing off of the Nevada Test Site. This project is the most comprehensive dose reconstruction project to date, and, since similar assessments are currently underway at several other locations within and outside the U.S., lessons from ORERP can be valuable. A major component of dose reconstruction is estimation of dose from radionuclide ingestion. The PATHWAY food-chain model was developed to estimate the amount of radionuclides ingested. For agricultural components of the human diet, PATHWAY predicts radionuclide concentrations and quantities ingested. To improve accuracy and model credibility, four components of model analysis were conducted: estimation of uncertainty in model predictions, estimation of sensitivity of model predictions to input parameters, and testing of model predictions against independent data (validation), and comparing predictions from PATHWAY with those from other models. These results identified strengths and weaknesses in the model and aided in establishing the confidence associated with model prediction, which is a critical component risk assessment and dose reconstruction. For fallout from the Nevada Test Site, by far, the largest internal doses were received by the thyroid. However, the predicted number of fatal cancers from ingestion dose was generally much smaller than the number predicted from external dose. The number of fatal cancers predicted from ingestion dose was also orders of magnitude below the normal projected cancer rate. Several lessons were learned during the study that are relevant to other dose reconstruction efforts

  10. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    Energy Technology Data Exchange (ETDEWEB)

    Alva-Sánchez, Héctor, E-mail: halva@ciencias.unam.mx [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico); Reynoso-Mejía, Alberto [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F., Mexico and Departamento de Neuroimagen, Instituto Nacional de (Mexico); Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús [Departamento de Neuroimagen, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico)

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  11. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    Science.gov (United States)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-11-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  12. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    International Nuclear Information System (INIS)

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens

  13. ESR dating of elephant teeth and radiation dose rate estimation in soil

    International Nuclear Information System (INIS)

    Chemical analysis of 238U, 232Th and 40K in the dentine as well as enamel of elephant tooth fossil has been carried out in order to estimate the internal absorbed dose rate of the specimens, which was estimated to be (39±4) mrad/y on the assumption of early uptake model of radionuclides. The external radiation dose rate in the soil including the contribution from cosmic rays was also estimated to be (175±18) mrad/y with the help of γ-ray spectroscopic techniques of the soil samples in which the specimens were buried. The 60Co γ-ray equivalent accumulated dose of (2±0.2) x 104 rad for the tooth enamel gave ''ESR age'' of (9±2) x 104 y, which falls in the geologically estimated range between 3 x 104 and 30 x 104 y before the present. (author)

  14. Extension of CASCADE.04 to estimate neutron fluence and dose rates and its validation

    Indian Academy of Sciences (India)

    H Kumawat; V Kumar; P Srinivasan

    2009-03-01

    Capability to compute neutron dose rate is introduced for the first time in the new version of the CASCADE.04 code. Two different methods, `track length estimator' and `collision estimator' are adapted for the estimation of neutron fluence rate needed to calculate the ambient dose rate. For the validation of the methods, neutron dose rates are experimentally measured at different locations of a 5Ci Am–Be source, shielded in Howitzer-type system and these results are compared with those estimated using (i) modified CASCADE.04.d and (ii) MCNP4A codes and it is found that the agreement is good. The paper presents details of modification and results of the comparative study.

  15. State Estimation for a Biological Phosphorus Removal Process using an Asymptotic Observer

    DEFF Research Database (Denmark)

    Larose, Claude Alain; Jørgensen, Sten Bay

    2001-01-01

    This study investigated the use of an asymptotic observer for state estimation in a continuous biological phosphorus removal process. The estimated states are the concentration of heterotrophic, autotrophic, and phosphorus accumulating organisms, polyphosphate, glycogen and PHA. The reaction scheme...

  16. Organ doses for reference adult male and female undergoing computed tomography estimated by Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choonsik; Kim, Kwang Pyo; Long, Daniel; Fisher, Ryan; Tien, Chris; Simon, Steven L.; Bouville, Andre; Bolch, Wesley E. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20852 (United States); Department of Nuclear Engineering, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States); Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20852 (United States); Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States)

    2011-03-15

    Purpose: To develop a computed tomography (CT) organ dose estimation method designed to readily provide organ doses in a reference adult male and female for different scan ranges to investigate the degree to which existing commercial programs can reasonably match organ doses defined in these more anatomically realistic adult hybrid phantomsMethods: The x-ray fan beam in the SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code MCNPX2.6. The simulated CT scanner model was validated through comparison with experimentally measured lateral free-in-air dose profiles and computed tomography dose index (CTDI) values. The reference adult male and female hybrid phantoms were coupled with the established CT scanner model following arm removal to simulate clinical head and other body region scans. A set of organ dose matrices were calculated for a series of consecutive axial scans ranging from the top of the head to the bottom of the phantoms with a beam thickness of 10 mm and the tube potentials of 80, 100, and 120 kVp. The organ doses for head, chest, and abdomen/pelvis examinations were calculated based on the organ dose matrices and compared to those obtained from two commercial programs, CT-EXPO and CTDOSIMETRY. Organ dose calculations were repeated for an adult stylized phantom by using the same simulation method used for the adult hybrid phantom. Results: Comparisons of both lateral free-in-air dose profiles and CTDI values through experimental measurement with the Monte Carlo simulations showed good agreement to within 9%. Organ doses for head, chest, and abdomen/pelvis scans reported in the commercial programs exceeded those from the Monte Carlo calculations in both the hybrid and stylized phantoms in this study, sometimes by orders of magnitude. Conclusions: The organ dose estimation method and dose matrices established in this study readily provides organ doses for a reference adult male and female for different

  17. Biological UV-doses and the effect on an ozone layer depletion

    International Nuclear Information System (INIS)

    Effective UV-doses were calculated based on the integrated product of the biological action spectrum and the solar radiation. The calculations included absorption and scattering of UV-radiation in the atmosphere, both for normal ozone conditions as well as for a depleted ozone layer. The effective annual UV-dose increases by approximately 4% per degree of latitude towards the equator. An ozone depletion of 1% increases the annual UV-dose by approximately 1% at 60o N. A large depletion of 50% over Scandinavia (60o N) would give this region an effective UV-dose similar to that obtained, with normal ozone conditions, at a latitude of 40o N (California or the Mediterranean countries). The Antarctic ozone hole increases the annual UV-dose by 20 to 25% which is a similar increase as that attained by moving 5 to 6 degrees of latitude nearer the equator. The annual UV-dose on higher latitudes is mainly determined by the summer values of ozone. Both the ozone values and the effective UV-doses vary from one year to another (within ±4%). No positive or negative trend is observed for Scandinavia from 1978 to 1988

  18. Influence of variations in dose and dose rates on biological effects of inhaled beta-emitting radionuclides

    International Nuclear Information System (INIS)

    The biological effects of inhaled β-emitting radionuclides, 90Y, 91Y, 144Ce and 90Sr, are being investigated in beagle dogs that received single acute exposures at 12 to 14 months of age. The aerosols studied have included 91YC13,144CeC13, 90SrC12, and 90Y, 91Y, 144Ce or 90Sr in aluminosilicate particles. Thus, 91YCl3, 144CeCl3 and the aluminosilicate containing radionuclide particles all resulted in significant exposures to lung; 91YC13, 144CeC13 an 90SrC12 resulted in significant exposures to bone; 91YC13 and 144 CeC13 resulted in significant exposures to liver. The higher initial doserate exposures have been more effective than low dose-rate exposures on a per-rad basis in producing early effects. To date (144CeO2, it was observed that, on a μCi initial lung burden per kilogram body weight basis, mice did not develop pulmonary tumours whereas beagle dogs did. To fid out the reason for this observation mice have been repeatedly exposed by inhalation to 144CeO2 to maintain lung burdens of 144Ce that resulted in radiation dose rates similar to that observed in beagle dogs. Several of the repeatedly exposed mice developed malignant pulmonary tumours. Thus, with similar dose rates and cumulative doses to the lung, mice and dogs responded in a similar manner to chronic β radiation

  19. Estimation of breast dose and cancer risk in chest and abdomen CT procedures

    International Nuclear Information System (INIS)

    The use of CT in medical diagnosis delivers radiation doses to patents that are higher than those from other radiological procedures. Lack of optimized protocols be an additional source of increased dose in developing countries. The aims of this study are first, to measure patient doses during CT chest and abdomen procedures, second, to estimate the radiation dose to the breast, and third to quantify the radiation risks during the procedures. Patient doses from two common CT examinations were obtained from four hospitals in Khartoum.The patient doses were estimated using measurement of CT dose indexes (CTDI), exposure-related parameters, and the IMPACT spreadsheet based on NRPB conversion factors. A large variation of mean organ doses among hospitals was observed for similar CT examinations. These variations largely originated from different CT scanning protocols used in different hospitals and scanner type. The largest range was found for CT of the chest, for which the dose varied from 2.3 to 47 (average 24.7) mSv and for abdomen CT, it was 1.6 to 18.8 (average 10.2) mSv. Radiation dose to the breast ranged from 1.6 to 32.9 mSv for the chest and 1.1 to 13.2 mSv for the abdomen. The radiation risk per procedure was high. The obtained values were mostly higher than the values of organ doses reported from the other studies. It was concluded that current clinical chest and abdomen protocols result in variable radiation doses to the breast. The magnitude of exposure may have implications for imaging strategies.(Author)

  20. Biological modelling of the radiation dose escalation effect of regional hyperthermia in cervical cancer

    International Nuclear Information System (INIS)

    Locoregional hyperthermia combined with radiotherapy significantly improves locoregional control and overall survival for cervical tumors compared to radiotherapy alone. In this study biological modelling is applied to quantify the effect of radiosensitization for three cervical cancer patients to evaluate the improvement in equivalent dose for the combination treatment with radiotherapy and hyperthermia. The Linear-Quadratic (LQ) model extended with temperature-dependent LQ-parameters α and β was used to model radiosensitization by hyperthermia and to calculate the conventional radiation dose that is equivalent in biological effect to the combined radiotherapy and hyperthermia treatment. External beam radiotherapy planning was performed based on a prescription dose of 46Gy in 23 fractions of 2Gy. Hyperthermia treatment using the AMC-4 system was simulated based on the actual optimized system settings used during treatment. The simulated hyperthermia treatments for the 3 patients yielded a T50 of 40.1 °C, 40.5 °C, 41.1 °C and a T90 of 39.2 °C, 39.7 °C, 40.4 °C, respectively. The combined radiotherapy and hyperthermia treatment resulted in a D95 of 52.5Gy, 55.5Gy, 56.9Gy in the GTV, a dose escalation of 7.3–11.9Gy compared to radiotherapy alone (D95 = 45.0–45.5Gy). This study applied biological modelling to evaluate radiosensitization by hyperthermia as a radiation-dose escalation for cervical cancer patients. This model is very useful to compare the effectiveness of different treatment schedules for combined radiotherapy and hyperthermia treatments and to guide the design of clinical studies on dose escalation using hyperthermia in a multi-modality setting

  1. Estimated collective effective dose to the population from nuclear medicine examinations in Slovenia

    International Nuclear Information System (INIS)

    A national survey of patient exposure from nuclear medicine diagnostic procedures was performed by Slovenian Radiation Protection Administration in order to estimate their contribution to the collective effective dose to the population of Slovenia. A set of 36 examinations with the highest contributions to the collective effective dose was identified. Data about frequencies and average administered activities of radioisotopes used for those examinations were collected from all nuclear medicine departments in Slovenia. A collective effective dose to the population and an effective dose per capita were estimated from the collected data using dose conversion factors. The total collective effective dose to the population from nuclear medicine diagnostic procedures in 2011 was estimated to 102 manSv, giving an effective dose per capita of 0.05 mSv. The comparison of results of this study with studies performed in other countries indicates that the nuclear medicine providers in Slovenia are well aware of the importance of patient protection measures and of optimisation of procedures

  2. Dose estimation in CT exams of the abdomen based on values of DLP

    International Nuclear Information System (INIS)

    One of the challenges of multidetector computerized tomography is to minimize the risk of ionizing radiation using optimized protocols since higher doses are necessary to obtain high image quality. It was also noted that, due to the geometry in image acquisition using MDCT becomes necessary to estimate dose values consistent with the hypothesis clinically and with the specificities of the tomographic equipment. The aim of this study was to estimate the doses in abdomen exams from the data recorded on the MDCT console and dimensions obtained from DICOM images of patients undergoing different clinical protocols. Were collected, from the image DICOM of 101 exams, values of the dose length product (DLP) provided by Philips Health Care - Brilliance 64 equipment console, in order to relate them with the dose values obtained by means of thermoluminescent dosimeters ( TLD ) of CasSo4:Mn placed on the surface of a cylindrical simulator abdomen acrylic manufactured under the technical - operational conditions for a typical abdomen exam. From the data obtained, it was possible to find a factor of 1.16 ( 5 % ) indicating that the DLP values Brilliance 64 console underestimate the doses and this should be used with correction factor to estimate the total dose of the patient. (author)

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

    International Nuclear Information System (INIS)

    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)

  4. Dose estimation of animal experiments at the THOR BNCT beam by NCTPlan and Xplan

    International Nuclear Information System (INIS)

    Dose estimation of animal experiments affects many subsequent derived quantities, such as RBE and CBE values. It is important to ensure the trustiness of calculated dose of the irradiated animals. However, the dose estimation was normally calculated using simplified geometries and tissue compositions, which led to rough results. This paper introduces the use of treatment planning systems NCTplan and Xplan for the dose estimation. A mouse was taken as an example and it was brought to hospital for micro-PET/CT scan. It was found that the critical organ doses of an irradiated mouse calculated by simplified model were unreliable in comparison to Xplan voxel model. The difference could reach the extent of several tenths percent. It is recommended that a treatment planning system should be introduced to future animal experiments to upgrade the data quality. - Highlights: • This study presents the new BNCT treatment planning system Xplan for animal experiments. • Xplan is based on a pixel-to-pixel conversion which has the same resolution as the CT images. • NCTplan and a simplified geometry for rat were used for the sake of comparison. • The spatial resolution applied in calculation is crucial to the reliability of estimated dose

  5. Environmental radioactivity investigation and external dose estimation in some districts of Yunnan Province

    International Nuclear Information System (INIS)

    Objective: To measure the current environmental radioactivity levels in some districts of Yunnan Province, and to estimate the external doses to local residents. Methods: The surface soil, aerosol and water samples were collected and analyzed by HPGe gamma spectrometry. Based on the estimation model selected by Ministry of Health in the nationwide soil survey,the doses to local residents from 238U, 226Ra, 232Th, 40K and 137Cs in environmental samples were estimated. CARI-6 software issued by FAA (Federal Aviation Administration) was used to estimate cosmic radiation dose to the local population. Results: The external annual dose rate to the local people was 1.13 mSv per year, of which 0.52 mSv per year was contributed by natural radionuclides in soil, 0.6 μ Sv per year by 137Cs in soil and 0.61 mSv per year by cosmic radiation. Conclusions: The cosmic radiation and natural radionuclides in soil might contribute 99.95% of external exposure dose, while artificial radionuclide 137Cs contribute 0.05% of external exposure dose. (authors)

  6. RADTRAD: A simplified model for RADionuclide Transport and Removal And Dose estimation

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, S.L.; Miller, L.A.; Monroe, D.K. [Sandia National Labs., Albuquerque, NM (United States); Heames, T.J. [ITSC, Albuquerque, NM (United States)

    1998-04-01

    This report documents the RADTRAD computer code developed for the U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation (NRR) to estimate transport and removal of radionuclides and dose at selected receptors. The document includes a users` guide to the code, a description of the technical basis for the code, the quality assurance and code acceptance testing documentation, and a programmers` guide. The RADTRAD code can be used to estimate the containment release using either the NRC TID-14844 or NUREG-1465 source terms and assumptions, or a user-specified table. In addition, the code can account for a reduction in the quantity of radioactive material due to containment sprays, natural deposition, filters, and other natural and engineered safety features. The RADTRAD code uses a combination of tables and/or numerical models of source term reduction phenomena to determine the time-dependent dose at user-specified locations for a given accident scenario. The code system also provides the inventory, decay chain, and dose conversion factor tables needed for the dose calculation. The RADTRAD code can be used to assess occupational radiation exposures, typically in the control room; to estimate site boundary doses; and to estimate dose attenuation due to modification of a facility or accident sequence.

  7. Development of mathematical model for estimation of entrance surface dose in mammography

    International Nuclear Information System (INIS)

    Computer simulation is a convenient and frequently used tool in the study of x-ray mammography, for the design of novel detector systems, the evaluation of dose deposition, x-ray technique optimization, and other applications. An important component in the simulation process is the accurate computer generation of x-ray spectra. A computer model for the generation of x-ray spectra in the mammographic energy rang from 18 keV to 40 ke V has been developed by Boone et al. Due to the lack of QC and dose measurement tools, in addition to unavailability of medical physics, a mathematical tool was developed for estimation of patient exposure and entrance dose. The proposed model require no assumptions concerning the physics of x-ray production in an x-ray tube, but rather makes use of x-ray spectra recently measured experimentally by John M Boone (Department of Radiology, University of California). Using experimental dose measurements for specific tube voltage and tube current the generated x-ray spectra were calibrated. The spectrum calibration factors show a tube voltage dependency. From the calibrated x-ray spectrum, the exposure and entrance dose were estimated for different k Vp and m A. Results show good agreement between the measured and estimated values for tube voltage between 18 to 45 k Vp with a good correlation of nearly 1 and equal slope. The maximum estimated different between the measured and the simulated dose is approximately equal to 0.07%.(Author)

  8. Estimation of organ and effective dose due to Compton backscatter security scans

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Michael E.; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin 53201 (United States)

    2012-06-15

    Purpose: To estimate organ and effective radiation doses due to backscatter security scanners using Monte Carlo simulations and a voxelized phantom set. Methods: Voxelized phantoms of male and female adults and children were used with the GEANT4 toolkit to simulate a backscatter security scan. The backscatter system was modeled based on specifications available in the literature. The simulations modeled a 50 kVp spectrum with 1.0 mm-aluminum-equivalent filtration and a previously measured exposure of approximately 4.6 {mu}R at 30 cm from the source. Photons and secondary interactions were tracked from the source until they reached zero kinetic energy or exited from the simulation's boundaries. The energy deposited in the phantoms' respective organs was tallied and used to calculate total organ dose and total effective dose for frontal, rear, and full scans with subjects located 30 and 75 cm from the source. Results: For a full screen, all phantoms' total effective doses were below the established 0.25 {mu}Sv standard, with an estimated maximum total effective dose of 0.07 {mu}Sv for full screen of a male child. The estimated maximum organ dose due to a full screen was 1.03 {mu}Gy, deposited in the adipose tissue of the male child phantom when located 30 cm from the source. All organ dose estimates had a coefficient of variation of less than 3% for a frontal scan and less than 11% for a rear scan. Conclusions: Backscatter security scanners deposit dose in organs beyond the skin. The effective dose is below recommended standards set by the Health Physics Society (HPS) and the American National Standards Institute (ANSI) assuming the system provides a maximum exposure of approximately 4.6 {mu}R at 30 cm.

  9. Variability in dose estimates associated with the food-chain transport and ingestion of selected radionuclides

    International Nuclear Information System (INIS)

    Dose predictions for the ingestion of 90Sr and 137Cs, using aquatic and terrestrial food chain transport models similar to those in the Nuclear Regulatory Commission's Regulatory Guide 1.109, are evaluated through estimating the variability of model parameters and determining the effect of this variability on model output. The variability in the predicted dose equivalent is determined using analytical and numerical procedures. In addition, a detailed discussion is included on 90Sr dosimetry. The overall estimates of uncertainty are most relevant to conditions where site-specific data is unavailable and when model structure and parameter estimates are unbiased. Based on the comparisons performed in this report, it is concluded that the use of the generic default parameters in Regulatory Guide 1.109 will usually produce conservative dose estimates that exceed the 90th percentile of the predicted distribution of dose equivalents. An exception is the meat pathway for 137Cs, in which use of generic default values results in a dose estimate at the 24th percentile. Among the terrestrial pathways of exposure, the non-leafy vegetable pathway is the most important for 90Sr. For 90Sr, the parameters for soil retention, soil-to-plant transfer, and internal dosimetry contribute most significantly to the variability in the predicted dose for the combined exposure to all terrestrial pathways. For 137Cs, the meat transfer coefficient the mass interception factor for pasture forage, and the ingestion dose factor are the most important parameters. The freshwater finfish bioaccumulation factor is the most important parameter for the dose prediction of 90Sr and 137Cs transported over the water-fish-man pathway

  10. Biological effects in lymphocytes irradiated with {sup 99m}Tc: determination of the curve dose-response; Efeitos biologicos em linfocitos irradiados com {sup 99m}Tc: determinacao da curva dose-resposta

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Romero Marcilio Barros Matias de

    2002-08-01

    Biological dosimetry estimates the absorbed dose taking into account changes in biological parameters. The most used biological indicator of an exposition to ionizing radiation is the quantification of chromosomal aberrations of lymphocytes from irradiated individuals. The curves of dose versus induced biological effects, obtained through bionalyses, are used in used in retrospective evaluations of the dose, mainly in the case of accidents. In this research, a simple model for electrons and photons transports was idealized to simulate the irradiation of lymphocytes with {sup 99m} Tc, representing a system used for irradiation of blood cells. The objective of the work was to establish a curve of dose versus frequencies of chromosomal aberrations in lymphocytes of human blood. For the irradiation of blood samples micro spheres of human serum of albumin (HSAM) market with {sup 99m} Tc were used, allowing the irradiation of blood with different administered activities of {sup 99m} Tc, making possible the study the cytogenetical effects as a function of such activities. The conditions of irradiation in vivo using HSAM spheres marked with {sup 99m} Tc were simulated with MCNP 4C (Monte Carlo N-Particle) code to obtain the dose-response curve. Soft tissue composition was employed to simulate blood tissue and the analyses of the curve of dose versus biological effect showed a linear quadratic response of the unstable chromosomal aberrations. As a result, the response of dose versus chromosomal aberrations of blood irradiation with {sup 99m} Tc was best fitted by the curve Y=(8,99 {+-}2,06) x 1-{sup -4} + (1,24 {+-}0,62) x 10{sup -2} D + (5,67 {+-} 0,64) x 10{sup -2} D{sup 2}. (author)

  11. Establishment of a γ-H2AX foci-based assay to determine biological dose of radon to red bone marrow in rats

    Science.gov (United States)

    Wang, Jing; He, Linfeng; Fan, Dunhuang; Ding, Defang; Wang, Xufei; Gao, Yun; Zhang, Xuxia; Li, Qiang; Chen, Honghong

    2016-07-01

    The biodosimetric information is critical for assessment of cancer risk in populations exposed to high radon. However, no tools are available for biological dose estimation following radon exposure. Here, we established a γ-H2AX foci-based assay to determine biological dose to red bone marrow (RBM) in radon-inhaled rats. After 1–3 h of in vitro radon exposure, a specific pattern of γ-H2AX foci, linear tracks with individual p-ATM and p-DNA-PKcs foci, was observed, and the yield of γ-H2AX foci and its linear tracks displayed a linear dose-response manner in both rat peripheral blood lymphocytes (PBLs) and bone-marrow lymphocytes (BMLs). When the cumulative doses of radon inhaled by rats reached 14, 30 and 60 working level months (WLM), the yields of three types of foci markedly increased in both PBLs and BMLs, and γ-H2AX foci-based dose estimates to RBM were 0.97, 2.06 and 3.94 mGy, respectively. Notably, BMLs displayed a more profound increase of three types of foci than PBLs, and the absorbed dose ratio between BMLs and PBLs was similar between rats exposed to 30 and 60 WLM of radon. Taken together, γ-H2AX foci quantitation in PBLs is able to estimate RBM-absorbed doses with the dose-response curve of γ-H2AX foci after in vitro radon exposure and the ratio of RBM- to PBL-absorbed doses in rats following radon exposure.

  12. Establishment of a γ-H2AX foci-based assay to determine biological dose of radon to red bone marrow in rats

    Science.gov (United States)

    Wang, Jing; He, Linfeng; Fan, Dunhuang; Ding, Defang; Wang, Xufei; Gao, Yun; Zhang, Xuxia; Li, Qiang; Chen, Honghong

    2016-01-01

    The biodosimetric information is critical for assessment of cancer risk in populations exposed to high radon. However, no tools are available for biological dose estimation following radon exposure. Here, we established a γ-H2AX foci-based assay to determine biological dose to red bone marrow (RBM) in radon-inhaled rats. After 1–3 h of in vitro radon exposure, a specific pattern of γ-H2AX foci, linear tracks with individual p-ATM and p-DNA-PKcs foci, was observed, and the yield of γ-H2AX foci and its linear tracks displayed a linear dose-response manner in both rat peripheral blood lymphocytes (PBLs) and bone-marrow lymphocytes (BMLs). When the cumulative doses of radon inhaled by rats reached 14, 30 and 60 working level months (WLM), the yields of three types of foci markedly increased in both PBLs and BMLs, and γ-H2AX foci-based dose estimates to RBM were 0.97, 2.06 and 3.94 mGy, respectively. Notably, BMLs displayed a more profound increase of three types of foci than PBLs, and the absorbed dose ratio between BMLs and PBLs was similar between rats exposed to 30 and 60 WLM of radon. Taken together, γ-H2AX foci quantitation in PBLs is able to estimate RBM-absorbed doses with the dose-response curve of γ-H2AX foci after in vitro radon exposure and the ratio of RBM- to PBL-absorbed doses in rats following radon exposure. PMID:27445126

  13. Establishment of a γ-H2AX foci-based assay to determine biological dose of radon to red bone marrow in rats.

    Science.gov (United States)

    Wang, Jing; He, Linfeng; Fan, Dunhuang; Ding, Defang; Wang, Xufei; Gao, Yun; Zhang, Xuxia; Li, Qiang; Chen, Honghong

    2016-01-01

    The biodosimetric information is critical for assessment of cancer risk in populations exposed to high radon. However, no tools are available for biological dose estimation following radon exposure. Here, we established a γ-H2AX foci-based assay to determine biological dose to red bone marrow (RBM) in radon-inhaled rats. After 1-3 h of in vitro radon exposure, a specific pattern of γ-H2AX foci, linear tracks with individual p-ATM and p-DNA-PKcs foci, was observed, and the yield of γ-H2AX foci and its linear tracks displayed a linear dose-response manner in both rat peripheral blood lymphocytes (PBLs) and bone-marrow lymphocytes (BMLs). When the cumulative doses of radon inhaled by rats reached 14, 30 and 60 working level months (WLM), the yields of three types of foci markedly increased in both PBLs and BMLs, and γ-H2AX foci-based dose estimates to RBM were 0.97, 2.06 and 3.94 mGy, respectively. Notably, BMLs displayed a more profound increase of three types of foci than PBLs, and the absorbed dose ratio between BMLs and PBLs was similar between rats exposed to 30 and 60 WLM of radon. Taken together, γ-H2AX foci quantitation in PBLs is able to estimate RBM-absorbed doses with the dose-response curve of γ-H2AX foci after in vitro radon exposure and the ratio of RBM- to PBL-absorbed doses in rats following radon exposure. PMID:27445126

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

    International Nuclear Information System (INIS)

    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)

  15. Estimation of dose distribution in occupationally exposed individuals to FDG-18F

    International Nuclear Information System (INIS)

    The use of unsealed radiation sources in nuclear medicine can lead to important incorporation of radionuclides, especially for occupationally exposed individuals (OEIs) during production and handling of radiopharmaceuticals. In this study, computer simulation was proposed as an alternative methodology for evaluation of the absorbed dose distribution and for the effective dose value in OEIs. For this purpose, the Exposure Computational Model (ECM) which is named as FSUP (Female Adult Mesh - supine) were used. This ECM is composed of: voxel phantom FASH (Female Adult MeSH) in the supine position, the MC code EGSnrc and an algorithm simulator of general internal source. This algorithm was modified to adapt to specific needs of the positron emission from FDG-18F. The obtained results are presented as absorbed dose/accumulated activity. To obtain the absorbed dose distribution it was necessary to use accumulative activity data from the in vivo bioassay. The absorbed dose distribution and the value of estimated effective dose in this study did not exceed the limits for occupational exposure. Therefore, the creation of a database with the distribution of accumulated activity is suggested in order to estimate the absorbed dose in radiosensitive organs and the effective dose for OEI in similar environment. (author)

  16. The new radiation dose estimation for people exposed to atomic bomb radiation in Nagasaki

    International Nuclear Information System (INIS)

    ABS93D (Atomic Bomb Survivor 1993 Dose) which being a method established in Atomic Bomb-Radiation Medical Institute of Hiroshima University for estimating the atomic-bomb radiation dose based on DS86 (Dosimetry System 1986), was applied for people exposed to Nagasaki atomic bomb radiation who had been registered in the Database Center for Atomic Bomb Radiation, School of Medicine, Nagasaki University. It was possible to estimate the dose for 10,022 people who had been present at the known distance from the explosion site and had been either exposed ''unshielded'' in the open-air or exposed ''shielded'' outdoors by a wooden construction or trees and indoors in a wooden construction. The population exposed at <0.005 Gy was calculated to be 19.1%, 0.005-1 Gy, 71.4%, and ≥1 Gy, 9.5%. Comparison of this ABS93D dose with the dose on T65D (Tentative 1965 Dose) in the same individuals revealed that the dose on ABS93D was lower than T65D dose. The method and parameters to calculate the free-air kerma, shield kerma and organ kerma based on ABS93D were presented in the appendix. (K.H.)

  17. Estimation of the effects of normal tissue sparing using equivalent uniform dose-based optimization

    Directory of Open Access Journals (Sweden)

    K Senthilkumar

    2016-01-01

    Full Text Available In this study, we intend to estimate the effects of normal tissue sparing between intensity modulated radiotherapy (IMRT treatment plans generated with and without a dose volume (DV-based physical cost function using equivalent uniform dose (EUD. Twenty prostate cancer patients were retrospectively selected for this study. For each patient, two IMRT plans were generated (i EUD-based optimization with a DV-based physical cost function to control inhomogeneity (EUDWith DV and (ii EUD-based optimization without a DV-based physical cost function to allow inhomogeneity (EUDWithout DV. The generated plans were prescribed a dose of 72 Gy in 36 fractions to planning target volume (PTV. Mean dose, D30%, and D5%were evaluated for all organ at risk (OAR. Normal tissue complication probability was also calculated for all OARs using BioSuite software. The average volume of PTV for all patients was 103.02 ± 27 cm3. The PTV mean dose for EUDWith DVplans was 73.67 ± 1.7 Gy, whereas for EUDWithout DVplans was 80.42 ± 2.7 Gy. It was found that PTV volume receiving dose more than 115% of prescription dose was negligible in EUDWith DV plans, whereas it was 28% in EUDWithout DV plans. In almost all dosimetric parameters evaluated, dose to OARs in EUDWith DVplans was higher than in EUDWithout DVplans. Allowing inhomogeneous dose (EUDWithout DV inside the target would achieve better normal tissue sparing compared to homogenous dose distribution (EUDWith DV. Hence, this inhomogeneous dose could be intentionally dumped on the high-risk volume to achieve high local control. Therefore, it was concluded that EUD optimized plans offer added advantage of less OAR dose as well as selectively boosting dose to gross tumor volume.

  18. Estimation of the effects of normal tissue sparing using equivalent uniform dose-based optimization.

    Science.gov (United States)

    Senthilkumar, K; Maria Das, K J; Balasubramanian, K; Deka, A C; Patil, B R

    2016-01-01

    In this study, we intend to estimate the effects of normal tissue sparing between intensity modulated radiotherapy (IMRT) treatment plans generated with and without a dose volume (DV)-based physical cost function using equivalent uniform dose (EUD). Twenty prostate cancer patients were retrospectively selected for this study. For each patient, two IMRT plans were generated (i) EUD-based optimization with a DV-based physical cost function to control inhomogeneity (EUDWith DV) and (ii) EUD-based optimization without a DV-based physical cost function to allow inhomogeneity (EUDWithout DV). The generated plans were prescribed a dose of 72 Gy in 36 fractions to planning target volume (PTV). Mean dose, D30%, and D5% were evaluated for all organ at risk (OAR). Normal tissue complication probability was also calculated for all OARs using BioSuite software. The average volume of PTV for all patients was 103.02 ± 27 cm(3). The PTV mean dose for EUDWith DV plans was 73.67 ± 1.7 Gy, whereas for EUDWithout DV plans was 80.42 ± 2.7 Gy. It was found that PTV volume receiving dose more than 115% of prescription dose was negligible in EUDWith DV plans, whereas it was 28% in EUDWithout DV plans. In almost all dosimetric parameters evaluated, dose to OARs in EUDWith DV plans was higher than in EUDWithout DV plans. Allowing inhomogeneous dose (EUDWithout DV) inside the target would achieve better normal tissue sparing compared to homogenous dose distribution (EUDWith DV). Hence, this inhomogeneous dose could be intentionally dumped on the high-risk volume to achieve high local control. Therefore, it was concluded that EUD optimized plans offer added advantage of less OAR dose as well as selectively boosting dose to gross tumor volume. PMID:27217624

  19. Long-term intercomparison of Spanish environmental dosimetry services. Study of transit dose estimations

    International Nuclear Information System (INIS)

    This paper presents the layout and results of a three-year follow-up of a national intercomparison campaign organized on a voluntary basis among the Spanish Laboratories in charge of environmental monitoring at and in the vicinity of Spanish nuclear installations. The dosemeters were exposed in the field at an environmental reference station with a known ambient dose equivalent, and controlled meteorological parameters. The study aimed at verifying the consistency of the different laboratories in estimating the ambient dose equivalent in realistic fields and to evaluate the influence of two different procedures to estimate the transit dose during the transfer of the dosemeters both from and to the dosimetric laboratory and the monitored site. All the results were within 20% of the reference doses for all the dosemeters tested, and in most cases they were within 10%

  20. Estimated Radiation Doses to the Israeli Population from Nuclear Medicine Diagnostic Procedures

    International Nuclear Information System (INIS)

    Nuclear medicine diagnostic procedures were analyzed with the purpose of estimating their contribution to the individual and collective radiation doses to the Israeli population. An annual average of thirty nuclear medicine diagnostic procedures per 1,000 population were performed in Israel around the year 1998. The estimated mean effective dose per procedure due to nuclear medicine was 10.9 mSv and the annual collective effective dose resulting from these procedures - 2,000 man-Sv or 0.3 mSv per capita. The level of radiation doses to the Israeli population resulting from nuclear medicine diagnostic is mainly due to the relatively high number of procedures per capita and to the frequent use of high activity, especially Tl-201, for cardiology imaging procedures

  1. MAXINE: An improved methodology for estimating maximum individual dose from chronic atmospheric radioactive releases

    International Nuclear Information System (INIS)

    An EXCEL reg-sign spreadsheet has been developed that, when combined with the PC version of XOQDOQ, will generate estimates of maximum individual dose from routine atmospheric releases of radionuclides. The spreadsheet, MAXINE, utilizes a variety of atmospheric dispersion factors to calculate radiation dose as recommended by the US Nuclear Regulatory Commission in Regulatory Guide 1.109 [USNRC 1977a]. The methodology suggested herein includes use of both the MAXINE spreadsheet and the PC version of XOQDOQ

  2. Estimated collective effective dose to the population from nuclear medicine examinations in Slovenia

    OpenAIRE

    Skrk, Damijan; Zontar, Dejan

    2013-01-01

    Background A national survey of patient exposure from nuclear medicine diagnostic procedures was performed by Slovenian Radiation Protection Administration in order to estimate their contribution to the collective effective dose to the population of Slovenia. Methods A set of 36 examinations with the highest contributions to the collective effective dose was identified. Data about frequencies and average administered activities of radioisotopes used for those examinations were collected from ...

  3. Estimation of fetal dose to patients undergoing diagnostic x-ray procedures

    International Nuclear Information System (INIS)

    The estimation of fetal dose incurred by patients undergoing various radiologic procedures can be very perplexing. The problem is especially critical for women who do not know that they are pregnant at the time of x-ray exposure. A description is offered of efforts to quantitate the fetal dose by after-the-fact calculations. Such conservatively employed calculations may be essential for a clinical decision regarding therapeutic abortion

  4. 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

  5. Report of task group on the biological basis for dose limitation in the skin

    International Nuclear Information System (INIS)

    Researchers have drawn attention to what they consider inconsistencies in the manner in which ICRP have considered skin in relation to the effective dose equivalent. They urge that the dose to the skin should be considered routinely for inclusion in the effective dose equivalent in the context of protection of individuals and population groups. They note that even with a weighting factor of only 0.01 that the dose to the skin can be a significant contributor to the effective dose equivalent including skin for practical exposure conditions. In the case of many exposures the risk to the skin can be ignored but exposure in an uniformly contaminated cloud that might occur with 85Kr the dose to the skin could contribute 60% of the stochastic risk if included in the effective dose equivalent with a WT of 0.01. Through the years and even today the same questions about radiation effects in the skin and dosimetry keep being asked. This report collates the available data and current understanding of radiation effects on the skin, and may make it possible to estimate risks more accurately and to improve the approach to characterizing skin irradiations. 294 refs., 29 figs

  6. Radiochemical separation and effective dose estimation due to ingestion of 90Sr

    International Nuclear Information System (INIS)

    Since 2007. Institute for Public Health of Federation of Bosnia and Herzegovina-Radiation Protection Centre, within the framework of monitoring of radioactivity of environment carried out measurement of specific activity of 90Sr content in selected food and water samples. The paper described the methods of measurement and radiochemical separation. Presented results, as average values of specific activity of 90Sr, were used for estimation of effective dose due to ingestion of 90Sr for 2007. and 2008. Estimated effective dose for 2007. due to ingestion of 90Sr for adults was 1,36 μSv and 2,03 μSv for children (10 year old), and for 2008. 0,67 μSv (adults) and 1,01 μSv (children 10 year old). Estimated effective doses for 2007. and 2008. are varied because of different average specific activity radionuclide 90Sr in selected samples of food, their number, species and origin. (author)

  7. The influence of low doses of ionizing radiation on biological systems

    International Nuclear Information System (INIS)

    Recent results concerning possible beneficial effects of low doses of ionizing radiation on biological systems are summarized. It is also pointed out on the basis of existing evidence that harmful effects on living organisms take place not only in the case of excess but also in the case of deficiency of ionizing radiation. Possibility of using radio-enhanced ultralow luminescence for studying hormesis phenomena is discussed. 24 refs., 4 figs. (author)

  8. Organ doses for reference pediatric and adolescent patients undergoing computed tomography estimated by Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choonsik; Kim, Kwang Pyo; Long, Daniel J.; Bolch, Wesley E. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20852 (United States); Department of Nuclear Engineering, Kyung Hee University, Gyeonggi-do, 446906 (Korea, Republic of); J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States)

    2012-04-15

    Purpose: To establish an organ dose database for pediatric and adolescent reference individuals undergoing computed tomography (CT) examinations by using Monte Carlo simulation. The data will permit rapid estimates of organ and effective doses for patients of different age, gender, examination type, and CT scanner model. Methods: The Monte Carlo simulation model of a Siemens Sensation 16 CT scanner previously published was employed as a base CT scanner model. A set of absorbed doses for 33 organs/tissues normalized to the product of 100 mAs and CTDI{sub vol} (mGy/100 mAs mGy) was established by coupling the CT scanner model with age-dependent reference pediatric hybrid phantoms. A series of single axial scans from the top of head to the feet of the phantoms was performed at a slice thickness of 10 mm, and at tube potentials of 80, 100, and 120 kVp. Using the established CTDI{sub vol}- and 100 mAs-normalized dose matrix, organ doses for different pediatric phantoms undergoing head, chest, abdomen-pelvis, and chest-abdomen-pelvis (CAP) scans with the Siemens Sensation 16 scanner were estimated and analyzed. The results were then compared with the values obtained from three independent published methods: CT-Expo software, organ dose for abdominal CT scan derived empirically from patient abdominal circumference, and effective dose per dose-length product (DLP). Results: Organ and effective doses were calculated and normalized to 100 mAs and CTDI{sub vol} for different CT examinations. At the same technical setting, dose to the organs, which were entirely included in the CT beam coverage, were higher by from 40 to 80% for newborn phantoms compared to those of 15-year phantoms. An increase of tube potential from 80 to 120 kVp resulted in 2.5-2.9-fold greater brain dose for head scans. The results from this study were compared with three different published studies and/or techniques. First, organ doses were compared to those given by CT-Expo which revealed dose

  9. Low doses of ionizing radiation: Relationship between biological benefit and damage induction. A synopsis

    International Nuclear Information System (INIS)

    Absorption of ionizing radiation in biological tissue stochastically interacts with constituent atoms and molecules and always generates energy deposition (track) events accompanied by bursts of reactive oxygen species (ROS). These ROS are quite similar to those ROS that arise abundantly and constantly by normal oxidative metabolism. ROS effects from either source need attention when assessing radiation-induced alterations in biological structure and function. Endogenous ROS alone induce about 106 DNA oxyadducts per cell per day compared to about 5x10-3 total DNA damage per average cell per day from background radiation exposure (1 mGy per year). At this background level, the corresponding ratio of probabilities of endogenous versus radiogenic DNA double strand breaks (DSBs) per cell per day is about 103 with some 25-40 % of low-LET caused radiogenic DNA-DSBs being of the multi-damage-site type. Radiogenic DNA damage increases in proportion to absorbed dose over a certain dose range. By evolution, tissues possess physiological mechanisms of protection against an array of potentially toxic agents, externally from the environment and endogenously from metabolism, mainly against the abundantly and constantly produced ROS. Ad hoc protection operates at a level that is genetically determined. Following small to moderate perturbation of cell-tissue homeostasis by a toxic impact, adaptive responses develop with a delay and may last from hours to weeks, even months, and aim at protecting the system against renewed insults. Protective responses encompass defense by scavenging mechanisms, DNA repair, damage removal largely by apoptosis and immune responses, as well as changes in cell proliferation. Acute low-dose irradiation below about 0.2 Gy can not only disturb cell-tissue homeostasis but also initiate adaptived protection that appears with a delay of hours and may last from less than a day to months. The balance between damage production and adaptive protection favors

  10. Dose-effect relationship based on the estimation of radiation cataract frequency

    International Nuclear Information System (INIS)

    The results of experiments on random bred mice concerning dose-effect relationship estimated by radiation cataract developing 1 year after x-ray irradiation at doses of 0.05, 0.5, 4, 7 and 10 Gy are presented. It was shown that the effect of ionizing radiation on the lens registerd by its opacity, could be threshold-free and described with the equation of the straight line. The authors found it appropriate to introduce a concept of a permissible risk dose causing a certain degree of cataract. In their opinion, the existing maximum tolerance radiation dose based on the absence of cataract at doses less than 7.5 Gy, should be lowered not less than by one order

  11. Fetal radiation dose estimates for I-131 sodium iodide in cases where conception occurs after administration

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, R.B.; Stabin, M.G. [Oak Ridge Inst. for Science and Education, TN (United States)

    1999-01-01

    After administration of I-131 to the female patient, the possibility of radiation exposure of the embryo/fetus exists if the patient becomes pregnant while radioiodine remains in the body. Fetal radiation dose estimates for such cases were calculated. Doses were calculated for various maternal thyroid uptakes and time intervals between administration and conception, including euthyroid and hyperthyroid cases. The maximum fetal dose calculating was about 9.8E-03 mGy/MBq, which occurred with 100% maternal thyroid uptake and a 1 week interval between administration and conception. Placental crossover of the small amount of radioiodine remaining 90 days after conception was also considered. Such crossover could result in an additional fetal dose of 9.8E-05 mGy/MBq and a maximum fetal thyroid self dose of 3.5E-04 mGy/MBq.

  12. Estimating effective dose for a cardiac catheterisation procedure with single or double personal dosemeters

    International Nuclear Information System (INIS)

    In most countries of the European Union legislation requires individual determination and registration of the dose to radiological workers exposed to ionising radiation to check whether dose limits are exceeded. To assess stochastic risk, ideally effective dose (E) should be known. In practice, personal dose equivalent [Hp(10)] is used as it can be measured with a personal dosemeter. The dosemeter reading may provide a reasonable assessment of Hp(10), but it may deviate strongly from E, in particular in radiology procedures for medical diagnosis or intervention when protective clothing like lead-equivalent apron and thyroid collar is worn. In the literature various correction factors and algorithms to convert readings of single or dual dosemeters to an estimate of E can be found. An illustrative example of a cardiac catheterisation procedure, in which dose calculations are made by Monte Carlo simulation of radiation transport, shows that such corrections may still yield considerable overestimation. (authors)

  13. Estimates of internal-dose equivalent from inhalation and ingestion of selected radionuclides

    International Nuclear Information System (INIS)

    This report presents internal radiation dose conversion factors for radionuclides of interest in environmental assessments of nuclear fuel cycles. This volume provides an updated summary of estimates of committed dose equivalent for radionuclides considered in three previous Oak Ridge National Laboratory (ORNL) reports. Intakes by inhalation and ingestion are considered. The International Commission on Radiological Protection (ICRP) Task Group Lung Model has been used to simulate the deposition and retention of particulate matter in the respiratory tract. Results corresponding to activity median aerodynamic diameters (AMAD) of 0.3, 1.0, and 5.0 μm are given. The gastorintestinal (GI) tract has been represented by a four-segment catenary model with exponential transfer of radioactivity from one segment to the next. Retention of radionuclides in systemic organs is characterized by linear combinations of decaying exponential functions, recommended in ICRP Publication 30. The first-year annual dose rate, maximum annual dose rate, and fifty-year dose commitment per microcurie intake of each radionuclide is given for selected target organs and the effective dose equivalent. These estimates include contributions from specified source organs plus the systemic activity residing in the rest of the body; cross irradiation due to penetrating radiations has been incorporated into these estimates. 15 references

  14. The use of chromosomic anomalies for the estimation of an accidental acute irradiation dose in man

    International Nuclear Information System (INIS)

    The induction of chromosome abnormalities (dicentrics, rings and fragments) in human blood samples subjected to cobalt 60 gamma irradiation was studied for 11 doses varying from 25 to 1800 rads. The chromosome aberrations were counted in lymphocytes after 48 hours of in vitro culture. The results obtained from the observation of 6400 cells made it possible to establish dose-effect relationships for each types of abnormality (dicentrics, dicentrics and rings, and fragments). The dose-effect relationships were used to estimate doses received by 9 workers submitted to relatively homogeneous global acute irradiation and for which an evaluation of the average absorbed dose was possible. There is in general a good agreement between the estimation of the average absorbed dose based on chromosome damage and the physical dosimeter data. The study of the time-dependent evolution of the chromosome abnormalities in the lymphocytes of irradiated subjects shows that dosimetric estimations based on lymphocyte chromosome abnormalities in human blood are valid for several weeks after irradiation

  15. Estimates of internal-dose equivalent from inhalation and ingestion of selected radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, D.E.

    1982-01-01

    This report presents internal radiation dose conversion factors for radionuclides of interest in environmental assessments of nuclear fuel cycles. This volume provides an updated summary of estimates of committed dose equivalent for radionuclides considered in three previous Oak Ridge National Laboratory (ORNL) reports. Intakes by inhalation and ingestion are considered. The International Commission on Radiological Protection (ICRP) Task Group Lung Model has been used to simulate the deposition and retention of particulate matter in the respiratory tract. Results corresponding to activity median aerodynamic diameters (AMAD) of 0.3, 1.0, and 5.0 ..mu..m are given. The gastorintestinal (GI) tract has been represented by a four-segment catenary model with exponential transfer of radioactivity from one segment to the next. Retention of radionuclides in systemic organs is characterized by linear combinations of decaying exponential functions, recommended in ICRP Publication 30. The first-year annual dose rate, maximum annual dose rate, and fifty-year dose commitment per microcurie intake of each radionuclide is given for selected target organs and the effective dose equivalent. These estimates include contributions from specified source organs plus the systemic activity residing in the rest of the body; cross irradiation due to penetrating radiations has been incorporated into these estimates. 15 references.

  16. Estimated Risk Level of Unified Stereotactic Body Radiation Therapy Dose Tolerance Limits for Spinal Cord.

    Science.gov (United States)

    Grimm, Jimm; Sahgal, Arjun; Soltys, Scott G; Luxton, Gary; Patel, Ashish; Herbert, Scott; Xue, Jinyu; Ma, Lijun; Yorke, Ellen; Adler, John R; Gibbs, Iris C

    2016-04-01

    A literature review of more than 200 stereotactic body radiation therapy spine articles from the past 20 years found only a single article that provided dose-volume data and outcomes for each spinal cord of a clinical dataset: the Gibbs 2007 article (Gibbs et al, 2007(1)), which essentially contains the first 100 stereotactic body radiation therapy (SBRT) spine treatments from Stanford University Medical Center. The dataset is modeled and compared in detail to the rest of the literature review, which found 59 dose tolerance limits for the spinal cord in 1-5 fractions. We partitioned these limits into a unified format of high-risk and low-risk dose tolerance limits. To estimate the corresponding risk level of each limit we used the Gibbs 2007 clinical spinal cord dose-volume data for 102 spinal metastases in 74 patients treated by spinal radiosurgery. In all, 50 of the patients were previously irradiated to a median dose of 40Gy in 2-3Gy fractions and 3 patients developed treatment-related myelopathy. These dose-volume data were digitized into the dose-volume histogram (DVH) Evaluator software tool where parameters of the probit dose-response model were fitted using the maximum likelihood approach (Jackson et al, 1995(3)). Based on this limited dataset, for de novo cases the unified low-risk dose tolerance limits yielded an estimated risk of spinal cord injury of ≤1% in 1-5 fractions, and the high-risk limits yielded an estimated risk of ≤3%. The QUANTEC Dmax limits of 13Gy in a single fraction and 20Gy in 3 fractions had less than 1% risk estimated from this dataset, so we consider these among the low-risk limits. In the previously irradiated cohort, the estimated risk levels for 10 and 14Gy maximum cord dose limits in 5 fractions are 0.4% and 0.6%, respectively. Longer follow-up and more patients are required to improve the risk estimates and provide more complete validation. PMID:27000514

  17. Biological monitoring to determine worker dose in a butadiene processing plant

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, W.E.; Hayes, R.B. [National Cancer Inst., Bethesda, MD (United States)

    1995-12-01

    Butadiene (BD) is a reactive gas used extensively in the rubber industry and is also found in combustion products. Although BD is genotoxic and acts as an animal carcinogen, the evidence for carcinogenicity in humans is limited. Extrapolation from animal studies on BD carcinogenicity to risk in humans has been controversial because of uncertainties regarding relative biologic exposure and related effects in humans vs. experimental animals. To reduce this uncertainty, a study was designed to characterize exposure to BD at a polymer production facility and to relate this exposure to mutational and cytogenetic effects. Biological monitoring was used to better assess the internal dose of BD received by the workers. Measurement of 1,2-dihydroxy-4-(N-acetylcysteinyl) butane (M1) in urine served as the biomarker in this study. M1 has been shown to correlate with area monitoring in previous studies. Most studies that relate exposure to a toxic chemical with its biological effects rely on exposure concentration as the dose metric; however, exposure concentration may or may not reflect the actual internal dose of the chemical.

  18. Estimation of radiation dose rates around medical isotopes production facility of Cyclotron

    International Nuclear Information System (INIS)

    The demand of the radio isotopes for medical application is increasing day by day. Cyclotron is a tool for production of these proton rich isotopes which are termed a SPECT and PET isotopes. The irradiated hot targets from a cyclotron bunker are transferred to the hot cells for processing chemically to obtain the required radioisotope. A pre estimation of dose rates at various locations of the hot cells with worst and normal operation conditions is essential. An exercise of estimation of worst cases also gives an idea about the dose to the workers and necessary preparedness without compromising on the regulatory aspects. 18F, 67Ga, 201Tl are the most important isotopes that will be produced in medical cyclotron. They are produced by bombarding proton on suitable target materials. The activated targets transferred to the hot cells from irradiated machine/production bunker. Chemist has to work at hot cells for chemical synthesis for 18F to form FDG. For SPECT isotope production target has to under go two stages of chemical synthesis. The dose rate estimation around the hot cells will give the estimation of dose to the radiation workers. In addition to medical isotope the other materials surrounding the target also get activated because of proton or neutron activation. The dose estimation depends on the total activity that is produced and the period of time for entire the chemical processing. The dose rate are estimated by using suitable expressions considering normal and worst scenario conditions. A procedure and a case was discussed and result shown both for normal and worse scenario case. It is observed that not only shielding many other factors like ventilation etc played important role. A case study was made and results are shown with the suggestive preventive measures. (author)

  19. Computational method for realistic estimates of the dose to active marrow

    International Nuclear Information System (INIS)

    Calculation of absorbed dose to active marrow from photon radiation is a complex problem because electronic equilibrium may not exist in the vicinity of soft tissue-bone mineral interfaces. Snyder et al. recognized the intractable geometry of trabecular bone in their studies of photon transport in the body and formulated marrow dose estimates in a conservative manner. Other investigators have noted that this approach leads to overestimate by factors of 3 or more at low photon energy. In this paper the absorbed dose is formulated in terms of physical and anatomical parameters defining the energy deposition in the marrow space. 17 references, 2 figures, 1 table

  20. Definition of the dose(tempo)-distribution in the biological irradiation-facility of the RIVM

    International Nuclear Information System (INIS)

    The RIVM biological irradiation facility (BBF) for the irradiation of biological samples and small animals is a self shielded device and can be safely operated in an existing laboratory environment. There are two 137Cs sources (15TBq) in a bilateral geometry to give maximum dose uniformity. The easily accessible irradiation chamber is housed in a rotating lead shielding. The dosimetry of BBF was performed by the Dosimetry Section of the RIVM. Experiments were made to determine the absorbed dose in plastic tubes filled with water and the dose distribution over the tube-holder. Separate experiments were made to determine the absorbed dose during the rotation of the irradiation chamber and to check the irradiation timer. For the experiments LiF:Mg,Ti (TLD-100) extruded ribbons were used. The TLDs were calibrated in a collimated beam of 137Cs gamma rays. The determination of the absorbed dose in water was based on a users biological irradiation set up. The TLDs were individually sealed in thin plastic foil and put in plastic tubes filled for 1/3 with water. The tubes were vertically placed in the tube-holder and placed in the centre of the irradiation chamber. The results show that the absorbed dose in water (determined on January 1, 1990) is equal to 0.97 Gy/timer-unit, with a total uncertainty of 7 percent (1σ). During the rotation of the irradiation chamber the absorbed dose (determined on January 1, 1990) is equal to 0.38 Gy, with a total uncertainty of 15 percent (1σ). The variation of the dose distribution was determined at 15 different measurement points distributed over the tube-holder. The dosis in the measurement point in the centre of the tube-holder was taken as reference value. The maximum observed deviation over the other 14 measurement points amounts to -16 percent of it. The BBF-timer was checked against a special timer. The results indicate that within a range from 2-11 'timer-units' no differences are present. (author). 6 refs.; 6 figs.; 3 fotos; 11

  1. Internal thyroid doses to Fukushima residents-estimation and issues remaining.

    Science.gov (United States)

    Kim, Eunjoo; Kurihara, Osamu; Kunishima, Naoaki; Momose, Takumaro; Ishikawa, Tetsuo; Akashi, Makoto

    2016-08-01

    Enormous quantities of radionuclides were released into the environment following the disastrous accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011. It is of great importance to determine the exposure doses received by the populations living in the radiologically affected areas; however, there has been significant difficulty in estimating the internal thyroid dose received through the intake of short-lived radionuclides (mainly, (131)I), because of the lack of early measurements on people. An estimation by the National Institute of Radiological Sciences for 1 April 2012 to 31 March 2013 was thus performed using a combination of the following three sources: thyroid measurement data ((131)I) for 1080 children examined in the screening campaign, whole-body counter measurement data ((134)Cs, (137)Cs) for 3000 adults, and atmospheric transport dispersion model simulations. In this study, the residents of Futaba town, Iitate village and Iwaki city were shown to have the highest thyroid equivalent dose, and their doses were estimated to be mostly below 30 mSv. However, this result involved a lot of uncertainties and provided only representative values for the residents. The present paper outlines a more recent dose estimation and preliminary analyses of personal behavior data used in the new method. PMID:27538842

  2. Estimates of Columbia River radionuclide concentrations: Data for Phase 1 dose calculations

    International Nuclear Information System (INIS)

    Pacific Northwest Laboratory is conducting the Hanford Environmental Dose Reconstruction Project to estimate the radiation doses people may have received from historical Hanford Site operations. Under the direction of an independent Technical Steering Panel, the project is being conducted in phases. The objective of the first phase is to assess the feasibility of the project-wide technical approach for acquiring data and developing models needed to calculate potential radiation doses. This report summarizes data that were generated for the Phase 1 dose calculations. These included monthly average concentrations of specific radionuclides in Columbia River water and sediments between Priest Rapids Dam and McNary Dam for the years 1964 to 1966. Nine key radionuclides were selected for analysis based on estimation of their contribution to dose. Concentrations of these radionuclides in the river were estimated using existing measurements and hydraulic calculations based on the simplifying assumption that dilution and decay were the primary processes controlling the fate of radionuclides released to the river. Five sub-reaches between Priest Rapids Dam and McNary Dam, corresponding to population centers and tributary confluences, were identified and monthly average radionuclide concentrations were calculated for each sub-reach. The hydraulic calculations were performed to provide radionuclide concentration estimates for time periods and geographic locations where measured data were not available. The validity of the calculation method will be evaluated in Phase 2. 12 refs., 13 figs., 49 tabs

  3. Estimation dose in organs of hyperthyroidism patients treated with I-131

    International Nuclear Information System (INIS)

    Full text: The absorbed dose in organs of hyperthyroidism patients, which received 370 MBq and 555 MBq of I-131 were estimated, using the MIRDOSE computational program and data of the ICRP-53 publication. The calculus were done considering an equal uptake to 45% and an effective half life of 5 days, these values are closed to the average values found in 17 studied patients. The thyroidal masses were previously determined by the physicians and varied between 40 g and 80 g The results showed that the dose in the thyroid, for an activity of 370 MBq, varied between 99 Gy and 49,5 Gy for the masses of 40 g and 80 g respectively. In the case of the administration of 555 MBq the patients had thyroidal masses between 60 g and 80 g and the doses varied between 99 Gy and 74,2 Gy, respectively. These values showed that the absorbed doses in thyroid are within limits expected for the hyperthyroidism therapy, which are of 506 Gy to 100 Gy. The 100 Gy dose would be exceeded, if the patients with thyroidal mass of 40 g had received a therapeutic dose of 555 MBq. The estimated media doses in others organs were relatively low, with inferior values of 0,1 Gy in kidneys, bone marrow and ovaries and of 0,19 Gy in stomach

  4. Fetus dose estimation in thyroid cancer post-surgical radioiodine therapy

    International Nuclear Information System (INIS)

    Unrecognised pregnancy during radioisotope therapy of thyroid cancer results in hardly definable embryo/fetus exposures, particularly when the thyroid gland is already removed. Sources of such difficulty include uncertainty in data like pregnancy commencing time, amount and distribution of metastasized thyroid cells in body, effect of the thyroidectomy on the fetus dose coefficient etc. Despite all these uncertainties, estimation of the order of the fetus dose in most cases is enough for medical and legal decision-making purposes. A model for adapting the dose coefficients recommended by the well-known methods to the problem of fetus dose assessment in athyrotic patients is proposed. The model defines a correction factor for the problem and ensures that the fetus dose in athyrotic pregnant patients is less than the normal patients. A case of pregnant patient undergone post-surgical therapy by I-131 is then studied for quantitative comparison of the methods. The results draw a range for the fetus dose in athyrotic patients using the derived factor. This reduces the concerns on under- or over-estimation of the embryo/fetus dose and is helpful for personal and/or legal decision-making on abortion. (authors)

  5. Comment on a mathematical model for estimating biological damage caused by radiation. Whack-A-Mole model

    International Nuclear Information System (INIS)

    We propose a mathematical model, Whack-A-Mole (WAM) model which can estimate the biological effect caused by radiation. The WAM model assumes that the basic element is a cell and the number of cells increases or decreases due to response to stimulus, damage and recovery, cause by radiation and so on. WAM takes into account dose rate as an important physical quantity, which marks a fundamental difference from target theory or LQ model. WAM model reproduces various experimental data of mutation frequency induced by radiation, for example, mega-mouse project. Furthermore, we can predict unknown experimental results. From WAM model, it is learnt that the mutation frequency caused by radiation is not proportional to dose but also have saturation value. There is some possibility that the WAM model will drastically change risk estimation of radiation as it brings us different results from those of target theory or LQ model. (author)

  6. Estimated effective dose of CT-guided percutaneous cryoablation of liver tumors

    International Nuclear Information System (INIS)

    Purpose: To estimate effective dose during CT-guided cryoablation of liver tumors, and to assess which procedural factors contribute most to dose. Materials and methods: Our institutional review board approved this retrospective, HIPAA-compliant study. A total of 20 CT-guided percutaneous liver tumor cryoablation procedures were performed in 18 patients. Effective dose was determined by multiplying the dose length product for each CT scan obtained during the procedure by a conversion factor (0.015 mSv/mGy-cm), and calculating the sum for each phase of the procedure: planning, targeting, monitoring, and post-ablation survey. Effective dose of each phase was compared using a repeated measures analysis. Using Spearman correlation coefficients, effective doses were correlated with procedural factors including number of scans, ratio of targeting distance to tumor size, anesthesia type, number of applicators, performance of ancillary procedures (hydrodissection and biopsy), and use of CT fluoroscopy. Results: Effective dose per procedure was 72 ± 18 mSv. The effective dose of targeting (37.5 ± 12.5 mSv) was the largest component compared to the effective dose of the planning phase (4.8 ± 2.2 mSv), the monitoring phase (25.5 ± 6.8 mSv), and the post-ablation survey (4.1 ± 1.9 mSv) phase (p < 0.05). Effective dose correlated positively only with the number of scans (p < 0.01). Conclusions: The effective dose of CT-guided percutaneous cryoablation of liver tumors can be substantial. Reducing the number of scans during the procedure is likely to have the greatest effect on lowering dose.

  7. Comparison of breast sequential and simultaneous integrated boost using the biologically effective dose volume histogram (BEDVH)

    International Nuclear Information System (INIS)

    A method is presented to radiobiologically compare sequential (SEQ) and simultaneously integrated boost (SIB) breast radiotherapy. The method is based on identically prescribed biologically effective dose (iso-BED) which was achieved by different prescribed doses due to different fractionation schemes. It is performed by converting the calculated three-dimensional dose distribution to the corresponding BED distribution taking into consideration the different number of fractions for generic α/β ratios. A cumulative BED volume histogram (BEDVH) is then derived from the BED distribution and is compared for the two delivery schemes. Ten breast cancer patients (4 right-sided and 6 left-sided) were investigated. Two tangential intensity modulated whole breast beams with two other oblique (with different gantry angles) beams for the boost volume were used. The boost and the breast target volumes with either α/β = 10 or 3 Gy, and ipsi-lateral and contra-lateral lungs, heart, and contra-lateral breast as organs at risk (OARs) with α/β = 3 Gy were compared. Based on the BEDVH comparisons, the use of SIB reduced the biological breast mean dose by about 3 %, the ipsi-lateral lung and heart by about 10 %, and contra-lateral breast and lung by about 7 %. BED based comparisons should always be used in comparing plans that have different fraction sizes. SIB schemes are dosimetrically more advantageous than SEQ in breast target volume and OARs for equal prescribed BEDs for breast and boost

  8. Gold nanoparticle-aided brachytherapy with vascular dose painting: Estimation of dose enhancement to the tumor endothelial cell nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Ngwa, Wilfred; Makrigiorgos, G. Mike; Berbeco, Ross I. [Department of Radiation Oncology, Division of Medical Physics and Biophysics, Brigham and Women' s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115 (United States)

    2012-01-15

    Purpose: Theoretical microdosimetry at the subcellular level is employed in this study to estimate the dose enhancement to tumor endothelial cell nuclei, caused by radiation-induced photo/Auger electrons originating from gold nanoparticles (AuNPs) targeting the tumor endothelium, during brachytherapy. Methods: A tumor vascular endothelial cell (EC) is modeled as a slab of 2 {mu}m (thickness) x 10 {mu}m (length) x 10 {mu}m (width). The EC contains a nucleus of 5 {mu}m diameter and thickness of 0.5-1 {mu}m, corresponding to nucleus size 5%-10% of cellular volume, respectively. Analytic calculations based on the electron energy loss formula of Cole were carried out to estimate the dose enhancement to the nucleus caused by photo/Auger electrons from AuNPs attached to the exterior surface of the EC. The nucleus dose enhancement factor (nDEF), representing the ratio of the dose to the nucleus with and without the presence of gold nanoparticles was calculated for different AuNP local concentrations. The investigated concentration range considers the potential for significantly higher local concentration near the EC due to preferential accumulation of AuNP in the tumor vasculature. Four brachytherapy sources: I-125, Pd-103, Yb-169, and 50 kVp x-rays were investigated. Results: For nucleus size of 10% of the cellular volume and AuNP concentrations ranging from 7 to 140 mg/g, brachytherapy sources Pd-103, I-125, 50 kVp, and Yb-169 yielded nDEF values of 5.6-73, 4.8-58.3, 4.7-56.6, and 3.2-25.8, respectively. Meanwhile, for nucleus size 5% of the cellular volume in the same concentration range, Pd-103, I-125, 50 kVp, and Yb-169 yielded nDEF values of 6.9-79.2, 5.1-63.2, 5.0-61.5, and 3.3-28.3, respectively. Conclusions: The results predict that a substantial dose boost to the nucleus of endothelial cells can be achieved by applying tumor vasculature-targeted AuNPs in combination with brachytherapy. Such vascular dose boosts could induce tumor vascular shutdown, prompting

  9. Radon air concentrations in karst caves and estimates of personal doses at employees

    International Nuclear Information System (INIS)

    The results are presented of the determination of seasonal variations of radon concentration in the air in 10 Slovak karst caves frequently visited by tourists, together with estimates of doses to 13 tourist guides from 7 caves over a 2 year period. Solid state nuclear track detectors of the CR-39 type were used to measure annual radon concentrations. Short-term measurements of radon and its progeny were performed by means of 170 ml Lucas cells. Personal doses were measured with a pair of CR-39 detectors in a passive two-chamber system. Results of the measurements and estimates are given in graphs and tables. (A.K.)

  10. Military Participants at U.S. Atmospheric Nuclear Weapons Testing— Methodology for Estimating Dose and Uncertainty

    OpenAIRE

    Till, John E.; Beck, Harold L.; Aanenson, Jill W.; Grogan, Helen A.; Mohler, H. Justin; Mohler, S. Shawn; Voillequé, Paul G.

    2014-01-01

    Methods were developed to calculate individual estimates of exposure and dose with associated uncertainties for a sub-cohort (1,857) of 115,329 military veterans who participated in at least one of seven series of atmospheric nuclear weapons tests or the TRINITY shot carried out by the United States. The tests were conducted at the Pacific Proving Grounds and the Nevada Test Site. Dose estimates to specific organs will be used in an epidemiological study to investigate leukemia and male breas...

  11. Dose estimation due to 129I release by nuclear installations. Local and regional scales

    International Nuclear Information System (INIS)

    On a regional scale, doses related to 129I release in the environment were calculated by two methods: the specific activity method and the critical pathway or transfer chain method. The transfer chain method evaluates all the possible pathways of man environmental exposure and calculates 129I concentration in the various part of the food chain and the corresponding exposure. This method enables a more realistic dose estimation than the specific activity method. On a regional scale, the published estimations of 129I release impact are few and based on very different hypothesis, nevertheless the results obtained are relatively similar

  12. Explanation of method of dose estimation using chromosome translocation with fluorescence in situ hybridization

    International Nuclear Information System (INIS)

    National occupational health standard-Method of Dose Estimation Using Chromosome Translocation with Fluorescence in Situ Hybridization has been developed, which based on comprehensive collection, reading and analysis of relevant literature both abroad and domestic and the existing diagnostic criteria for radiation diseases of the China, and the repeated experimental verification. This standard is mainly applied for dose estimation for individuals who previously exposed to irradiation by accident, and provide the scientific diagnosis of radiation sickness. To better understand and implement it, the contents of this standard were interpreted in this article. (authors)

  13. Combined methodology for estimating dose rates and health effects from exposure to radioactive pollutants

    International Nuclear Information System (INIS)

    The work described in the report is basically a synthesis of two previously existing computer codes: INREM II, developed at the Oak Ridge National Laboratory (ORNL); and CAIRD, developed by the Environmental Protection Agency (EPA). The INREM II code uses contemporary dosimetric methods to estimate doses to specified reference organs due to inhalation or ingestion of a radionuclide. The CAIRD code employs actuarial life tables to account for competing risks in estimating numbers of health effects resulting from exposure of a cohort to some incremental risk. The combined computer code, referred to as RADRISK, estimates numbers of health effects in a hypothetical cohort of 100,000 persons due to continuous lifetime inhalation or ingestion of a radionuclide. Also briefly discussed in this report is a method of estimating numbers of health effects in a hypothetical cohort due to continuous lifetime exposure to external radiation. This method employs the CAIRD methodology together with dose conversion factors generated by the computer code DOSFACTER, developed at ORNL; these dose conversion factors are used to estimate dose rates to persons due to radionuclides in the air or on the ground surface. The combination of the life table and dosimetric guidelines for the release of radioactive pollutants to the atmosphere, as required by the Clean Air Act Amendments of 1977

  14. Estimating Effective Dose from Phantom Dose Measurements in Atrial Fibrillation Ablation Procedures and Comparison of MOSFET and TLD Detectors in a Small Animal Dosimetry Setting

    Science.gov (United States)

    Anderson-Evans, Colin David

    Two different studies will be presented in this work. The first involves the calculation of effective dose from a phantom study which simulates an atrial fibrillation (AF) ablation procedure. The second involves the validation of metal-oxide semiconducting field effect transistors (MOSFET) for small animal dosimetry applications as well as improved characterization of the animal irradiators on Duke University's campus. Atrial Fibrillation is an ever increasing health risk in the United States. The most common type of cardiac arrhythmia, AF is associated with increased mortality and ischemic cerebrovascular events. Managing AF can include, among other treatments, an interventional procedure called catheter ablation. The procedure involves the use of biplane fluoroscopy during which a patient can be exposed to radiation for as much as two hours or more. The deleterious effects of radiation become a concern when dealing with long fluoroscopy times, and because the AF ablation procedure is elective, it makes relating the risks of radiation ever more essential. This study hopes to quantify the risk through the derivation of dose conversion coefficients (DCCs) from the dose-area product (DAP) with the intent that DCCs can be used to provide estimates of effective dose (ED) for typical AF ablation procedures. A bi-plane fluoroscopic and angiographic system was used for the simulated AF ablation procedures. For acquisition of organ dose measurements, 20 diagnostic MOSFET detectors were placed at selected organs in a male anthropomorphic phantom, and these detectors were attached to 4 bias supplies to obtain organ dose readings. The DAP was recorded from the system console and independently validated with an ionization chamber and radiochromic film. Bi-plane fluoroscopy was performed on the phantom for 10 minutes to acquire the dose rate for each organ, and the average clinical procedure time was multiplied by each organ dose rate to obtain individual organ doses. The

  15. Deterministic absorbed dose estimation in computed tomography using a discrete ordinates method

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Edward T.; Liu, Xin, E-mail: xinliu@mst.edu [Nuclear Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States); Hsieh, Jiang [GE Healthcare, Waukesha, Wisconsin 53188 (United States)

    2015-07-15

    Purpose: Organ dose estimation for a patient undergoing computed tomography (CT) scanning is very important. Although Monte Carlo methods are considered gold-standard in patient dose estimation, the computation time required is formidable for routine clinical calculations. Here, the authors instigate a deterministic method for estimating an absorbed dose more efficiently. Methods: Compared with current Monte Carlo methods, a more efficient approach to estimating the absorbed dose is to solve the linear Boltzmann equation numerically. In this study, an axial CT scan was modeled with a software package, Denovo, which solved the linear Boltzmann equation using the discrete ordinates method. The CT scanning configuration included 16 x-ray source positions, beam collimators, flat filters, and bowtie filters. The phantom was the standard 32 cm CT dose index (CTDI) phantom. Four different Denovo simulations were performed with different simulation parameters, including the number of quadrature sets and the order of Legendre polynomial expansions. A Monte Carlo simulation was also performed for benchmarking the Denovo simulations. A quantitative comparison was made of the simulation results obtained by the Denovo and the Monte Carlo methods. Results: The difference in the simulation results of the discrete ordinates method and those of the Monte Carlo methods was found to be small, with a root-mean-square difference of around 2.4%. It was found that the discrete ordinates method, with a higher order of Legendre polynomial expansions, underestimated the absorbed dose near the center of the phantom (i.e., low dose region). Simulations of the quadrature set 8 and the first order of the Legendre polynomial expansions proved to be the most efficient computation method in the authors’ study. The single-thread computation time of the deterministic simulation of the quadrature set 8 and the first order of the Legendre polynomial expansions was 21 min on a personal computer

  16. Deterministic absorbed dose estimation in computed tomography using a discrete ordinates method

    International Nuclear Information System (INIS)

    Purpose: Organ dose estimation for a patient undergoing computed tomography (CT) scanning is very important. Although Monte Carlo methods are considered gold-standard in patient dose estimation, the computation time required is formidable for routine clinical calculations. Here, the authors instigate a deterministic method for estimating an absorbed dose more efficiently. Methods: Compared with current Monte Carlo methods, a more efficient approach to estimating the absorbed dose is to solve the linear Boltzmann equation numerically. In this study, an axial CT scan was modeled with a software package, Denovo, which solved the linear Boltzmann equation using the discrete ordinates method. The CT scanning configuration included 16 x-ray source positions, beam collimators, flat filters, and bowtie filters. The phantom was the standard 32 cm CT dose index (CTDI) phantom. Four different Denovo simulations were performed with different simulation parameters, including the number of quadrature sets and the order of Legendre polynomial expansions. A Monte Carlo simulation was also performed for benchmarking the Denovo simulations. A quantitative comparison was made of the simulation results obtained by the Denovo and the Monte Carlo methods. Results: The difference in the simulation results of the discrete ordinates method and those of the Monte Carlo methods was found to be small, with a root-mean-square difference of around 2.4%. It was found that the discrete ordinates method, with a higher order of Legendre polynomial expansions, underestimated the absorbed dose near the center of the phantom (i.e., low dose region). Simulations of the quadrature set 8 and the first order of the Legendre polynomial expansions proved to be the most efficient computation method in the authors’ study. The single-thread computation time of the deterministic simulation of the quadrature set 8 and the first order of the Legendre polynomial expansions was 21 min on a personal computer

  17. Estimation of skyshine dose from turbine building of BWR plant using Monte Carlo code

    International Nuclear Information System (INIS)

    The Monte Carlo N-Particle transport code (MCNP) was adopted to calculate the skyshine dose from the turbine building of a BWR plant for obtaining precise estimations at the site boundary. In MCNP calculation, the equipment and piping arranged on the operating floor of the turbine building were considered and modeled in detail. The inner and outer walls of the turbine building, the shielding materials around the high-pressure turbine, and the piping connected from the moisture separator to the low-pressure turbine were all considered. A three-step study was conducted to estimate the applicability of MCNP code. The first step is confirming the propriety of calculation models. The atmospheric relief diaphragms, which are installed on top of the low-pressure turbine exhaust hood, are not considered in the calculation model. There was little difference between the skyshine dose distributions that were considered when using and not using the atmospheric relief diaphragms. The calculated dose rates agreed well with the measurements taken around the turbine. The second step is estimating the dose rates on the outer roof surface of the turbine building. This calculation was made to confirm the dose distribution of gamma-rays on the turbine roof before being scattered into the air. The calculated dose rates agreed well with the measured data. The third step is making a final confirmation by comparing the calculations and measurements of skyshine dose rates around the turbine building. The source terms of the main steam system are based on the measured activity data of N-16 and C-15. As a conclusion, we were able to calculate reasonable skyshine dose rates by using MCNP code. (authors)

  18. Estimation of frequency, population doses and stochastic risks in stomach mass screening examinations in Japan, 1980

    International Nuclear Information System (INIS)

    The population doses and the stochastic risks from stomach photofluorographic examinations were estimated on the basis of a nationwide survey. The annual number of photofluorographic examinations was 2.14 million for male and 1.96 million for female, with a total of 4.10 million. Organ or tissue doses related to the stochastic effects were determined with a phantom measurement using X-ray apparatuses of stomach mass screening. The average organ or tissue dose per full examination was evaluated from the experimental data by assuming mean technical factors such as X-ray tube voltage and body thickness of preson, based on the results of nationwide survey. The collective effective dose equivalent from stomach mass screening was 16, 135 man Sv, which was calculated according to the ICRP recommendation. The per Caput mean effective dose equivalent was 0.37 cSv for male and 0.42 for female, including skin cancer. The annual population doses were 1.8 Gy for genetically significant dose, 117 μGy for per Caput mean bone arrow dose, 100 μGy for leukemia significant dose and 79.4 μGy for malignant significant dose. The population risks, which were calculated using the population doses and risk factors of stochastic effects were 3 for genetic effects, 24 for leukemia and 153 for malignant diseases, respectively, for the whole population of Japan. The individual stochastic risks from photofluorographic examinations for stomach mass screening were lower than the risks from radiographic examination for stomach X-ray diagnosis. (author)

  19. Estimate of the absorbed dose in the mouse organs and tissues after tritium administration

    International Nuclear Information System (INIS)

    Chronic and accidental release of tritium from future fusion facilities may cause some extent of hazardous effect to the public health. Various experiments using small animals such as mice have been performed to mimic the dose accumulation due to tritium intake by the human body. An difficulty in such animal experiments using small animals is that it is rather difficult to administer tritium orally and estimate the dose to small organs or tissues. In the course of our study, a simple method to administer THO and T-labeled amino acids orally to the mouse was dictated and dose accumulation in various organs and tissues was determined. The tritium retention in the bone marrow was also determined using the micro-centrifuge method. Throughout our experiment, colony-bred DDY mice were used. The 8-10 week old male mice were orally and intraperitoneally administered THO water or T-amino acids mixture solution. For the purpose of oral administration, a 10 μl aliquot of T-containing saline solution was placed on the tongue of the mice using an automatic micropipette. At various times after tritium administration, the animals were sacrificed and the amount of tritium in various tissues and organs including bone marrow was examined. Dose accumulation pattern after THO intake and T-amino acids was compared between intraperitoneal injection and oral administration. The accumulated dose after oral administration of THO exhibited a tendency to be 10-20% higher than after intraperitoneal injection. The bone marrow dose after oral intake of THO was found to be lower than the doses to urine, blood, liver and testis. In contrast, the blood dose gave a conservative estimate for the dose to the other tissues and organs. (author)

  20. Early biological effects of low doses of ionizing radiation on yeast cells

    International Nuclear Information System (INIS)

    The biological effectiveness of different radiation types for variety organisms requires further study. For fundamental studies of this problem it is worthwhile to use the most thoroughly investigated biological objects, for example, yeasts. The yeast Saccharomyces cerevisiae was used as the test eukaryotic organism which gives the experimenter complete control over its chemical and physical environment. The aim of the study consisted in comparative analysis of early effects induced by low doses of low LET (60Co and 137Cs) and high LET ( α-particles 239Pu, neutrons) radiation on eukaryotic cells (cell survival about 100%). Biological effects of low doses of ionizing radiation were studied by two criteria: 1.delay of cell division and kinetics of yeast cells micro-colonies formation; 2.morphology of micro-colonies at different temperature. The results have shown that only small part of irradiated cell population (∼10%) divided at the same rate as unirradiated cells. Other part of cells had a delayed division. Unirradiated control cells formed typical micro-colonies at the solid nutrient media (YEPD) after 10 15 h of incubation. The fraction of cells population (20- 25%) exposed to low doses of?-particles or neutrons formed spectrum of untypical micro-colonies for the same incubation time, which consisted of small number of larger and more elongated cells. Some of these micro-colonies had 10 50 cells were of exotic forms ('spider'), differed from other micro-colonies in population. Using this method we can reveal an early response of cells at very low doses (survival about 100%) and determine the number non-lethally damaged cells. (author)

  1. Uncertainties in estimating dose-effects relationships under emergency (Hiroshima, Nagasaki 1945, Bikini 1954)

    International Nuclear Information System (INIS)

    There are many types of uncertainties involved in the estimation of risks or dose-effect relationships under emergency conditions, However, they may be divided into two major categories: uncertainty due to randomness and that due to fuzziness. The conventional methods of treating uncertainty are to apply statistical methods of estimation, which are, in turn, based upon the concept of probability. Even in cases where the source of uncertainty is of non-statistical nature, formal application of statistical methods of analysis is often made to deal quantitatively with uncertainty, tacitly accepting the premise that uncertainty - whatever its nature - can be equated with randomness. Most of the work on risk analysis or risk assessment has been done using such methods. In the fuzzy set concept set uncertainties are accepted as uncertain with the introduction of the membership function. Instead of the non-fuzzy two-valued logic 'true or false' any intermediate value between zero (false) and one (true) can be assumed for the membership function in the fuzzy set theory. Use of the fuzzy set theory is proposed in an attempt to analyse the causal relation between dose and effects under emergency conditions. After the atomic bombings in Hiroshima and Nagasaki and the Bikini Accident many efforts have been made to estimate the dose of survivors. However, because of various uncertainties involved in this type of estimation under the emergency conditions, the accurate estimation of the individual dose is very difficult. It was recently reported that ESR dosimetry could be applied to estimate the radiation doses of the individual using the enamel of the teeth of the survivors or material such as shell-button, sugar etc. found on the person. (author)

  2. Age- and gender-specific estimates of cumulative CT dose over 5 years using real radiation dose tracking data in children

    International Nuclear Information System (INIS)

    It is necessary to develop a mechanism to estimate and analyze cumulative radiation risks from multiple CT exams in various clinical scenarios in children. To identify major contributors to high cumulative CT dose estimates using actual dose-length product values collected for 5 years in children. Between August 2006 and July 2011 we reviewed 26,937 CT exams in 13,803 children. Among them, we included 931 children (median age 3.5 years, age range 0 days-15 years; M:F = 533:398) who had 5,339 CT exams. Each child underwent at least three CT scans and had accessible radiation dose reports. Dose-length product values were automatically extracted from DICOM files and we used recently updated conversion factors for age, gender, anatomical region and tube voltage to estimate CT radiation dose. We tracked the calculated CT dose estimates to obtain a 5-year cumulative value for each child. The study population was divided into three groups according to the cumulative CT dose estimates: high, ≥30 mSv; moderate, 10-30 mSv; and low, <10 mSv. We reviewed clinical data and CT protocols to identify major contributors to high and moderate cumulative CT dose estimates. Median cumulative CT dose estimate was 5.4 mSv (range 0.5-71.1 mSv), and median number of CT scans was 4 (range 3-36). High cumulative CT dose estimates were most common in children with malignant tumors (57.9%, 11/19). High frequency of CT scans was attributed to high cumulative CT dose estimates in children with ventriculoperitoneal shunt (35 in 1 child) and malignant tumors (range 18-49). Moreover, high-dose CT protocols, such as multiphase abdomen CT (median 4.7 mSv) contributed to high cumulative CT dose estimates even in children with a low number of CT scans. Disease group, number of CT scans, and high-dose CT protocols are major contributors to higher cumulative CT dose estimates in children. (orig.)

  3. Age- and gender-specific estimates of cumulative CT dose over 5 years using real radiation dose tracking data in children

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eunsol; Goo, Hyun Woo; Lee, Jae-Yeong [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of)

    2015-08-15

    It is necessary to develop a mechanism to estimate and analyze cumulative radiation risks from multiple CT exams in various clinical scenarios in children. To identify major contributors to high cumulative CT dose estimates using actual dose-length product values collected for 5 years in children. Between August 2006 and July 2011 we reviewed 26,937 CT exams in 13,803 children. Among them, we included 931 children (median age 3.5 years, age range 0 days-15 years; M:F = 533:398) who had 5,339 CT exams. Each child underwent at least three CT scans and had accessible radiation dose reports. Dose-length product values were automatically extracted from DICOM files and we used recently updated conversion factors for age, gender, anatomical region and tube voltage to estimate CT radiation dose. We tracked the calculated CT dose estimates to obtain a 5-year cumulative value for each child. The study population was divided into three groups according to the cumulative CT dose estimates: high, ≥30 mSv; moderate, 10-30 mSv; and low, <10 mSv. We reviewed clinical data and CT protocols to identify major contributors to high and moderate cumulative CT dose estimates. Median cumulative CT dose estimate was 5.4 mSv (range 0.5-71.1 mSv), and median number of CT scans was 4 (range 3-36). High cumulative CT dose estimates were most common in children with malignant tumors (57.9%, 11/19). High frequency of CT scans was attributed to high cumulative CT dose estimates in children with ventriculoperitoneal shunt (35 in 1 child) and malignant tumors (range 18-49). Moreover, high-dose CT protocols, such as multiphase abdomen CT (median 4.7 mSv) contributed to high cumulative CT dose estimates even in children with a low number of CT scans. Disease group, number of CT scans, and high-dose CT protocols are major contributors to higher cumulative CT dose estimates in children. (orig.)

  4. A novel method of estimating effective dose from the point dose method: a case study—parathyroid CT scans

    International Nuclear Information System (INIS)

    The purpose of this study was to validate a novel approach of applying a partial volume correction factor (PVCF) using a limited number of MOSFET detectors in the effective dose (E) calculation. The results of the proposed PVCF method were compared to the results from both the point dose (PD) method and a commercial CT dose estimation software (CT-Expo). To measure organ doses, an adult female anthropomorphic phantom was loaded with 20 MOSFET detectors and was scanned using the non-contrast and 2 phase contrast-enhanced parathyroid imaging protocols on a 64-slice multi-detector computed tomography scanner. E was computed by three methods: the PD method, the PVCF method, and the CT-Expo method. The E (in mSv) for the PD method, the PVCF method, and CT-Expo method was 2.6  ±  0.2, 1.3  ±  0.1, and 1.1 for the non-contrast scan, 21.9  ±  0.4, 13.9  ±  0.2, and 14.6 for the 1st phase of the contrast-enhanced scan, and 15.5  ±  0.3, 9.8  ±  0.1, and 10.4 for the 2nd phase of the contrast-enhanced scan, respectively. The E with the PD method differed from the PVCF method by 66.7% for the non-contrast scan, by 44.9% and by 45.5% respectively for the 1st and 2nd phases of the contrast-enhanced scan. The E with PVCF was comparable to the results from the CT-Expo method with percent differences of 15.8%, 5.0%, and 6.3% for the non-contrast scan and the 1st and 2nd phases of the contrast-enhanced scan, respectively. To conclude, the PVCF method estimated E within 16% difference as compared to 50–70% in the PD method. In addition, the results demonstrate that E can be estimated accurately from a limited number of detectors. (paper)

  5. Estimation of absorbed radiation dose rates in wild rodents inhabiting a site severely contaminated by the Fukushima Dai-ichi nuclear power plant accident

    International Nuclear Information System (INIS)

    The dose rates of radiation absorbed by wild rodents inhabiting a site severely contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident were estimated. The large Japanese field mouse (Apodemus speciosus), also called the wood mouse, was the major rodent species captured in the sampling area, although other species of rodents, such as small field mice (Apodemus argenteus) and Japanese grass voles (Microtus montebelli), were also collected. The external exposure of rodents calculated from the activity concentrations of radiocesium (134Cs and 137Cs) in litter and soil samples using the ERICA (Environmental Risk from Ionizing Contaminants: Assessment and Management) tool under the assumption that radionuclides existed as the infinite plane isotropic source was almost the same as those measured directly with glass dosimeters embedded in rodent abdomens. Our findings suggest that the ERICA tool is useful for estimating external dose rates to small animals inhabiting forest floors; however, the estimated dose rates showed large standard deviations. This could be an indication of the inhomogeneous distribution of radionuclides in the sampled litter and soil. There was a 50-fold difference between minimum and maximum whole-body activity concentrations measured in rodents at the time of capture. The radionuclides retained in rodents after capture decreased exponentially over time. Regression equations indicated that the biological half-life of radiocesium after capture was 3.31 d. At the time of capture, the lowest activity concentration was measured in the lung and was approximately half of the highest concentration measured in the mixture of muscle and bone. The average internal absorbed dose rate was markedly smaller than the average external dose rate (<10% of the total absorbed dose rate). The average total absorbed dose rate to wild rodents inhabiting the sampling area was estimated to be approximately 52 μGy h−1 (1.2 mGy d−1), even 3 years after

  6. Relative biological effectiveness of 125I seeds for low-dose-rate irradiation of PANC-1

    International Nuclear Information System (INIS)

    Objective: To investigate the relative biological effectiveness(RBE) of National Model 6711 125I seeds and the response patterns of PANC-1 exposed to 125I seeds irradiation. Methods: PANC-1 cells in exponential growth were irradiated at initial dose rate of 2.59 cGy/h in vitro and exposed to 1, 2, 4, 6, 8 and 10 Gy. Meanwhile, the other part of cells were exposed to the same doses by 60Co at dose rate of 2.21 Gy/min. After irradiation, the cells were stained by trypan blue to measure the cellular mortality rate and to compare the changes along with plating times of 12, 24, 48 and 72 h after 4 Gy. The colonies were counted to obtain the plating efficiencies by colony-forming assay and the cell surviving faction was calculated to plot cell survival curves, and RBE of 125I seeds relative to 60Co was determined. Results: The cell death rate for continuous low- dose-rate (LDR) irradiation by 125I seeds was greater than 60Co at the same doses above or equal to 4 Gy. After 4 Gy irradiation, the cellular mortality rates were increased with times. The difference was significant between 125I seeds and 60Co. The survival fractions of 125I were lower than those of 60Co, and the RBE of 125I relative to 60Co was determined to be 1.45. Conclusion: The cell-killing effects for continuous low-dose-rate (LDR) irradiation by 125I seeds are greater than acute high-dose-rate of 60Co. (authors)

  7. Estimated collective effective dose to the population from radiological examinations in Slovenia

    International Nuclear Information System (INIS)

    The aim of the study was to systematically evaluate population exposure from diagnostic and interventional radiological procedures in Slovenia. The study was conducted in scope of the “Dose Datamed 2” project. A standard methodology based on 20 selected radiological procedures was adopted. Frequencies of the procedures were determined via questionnaires that were sent to all providers of radiological procedures while data about patient exposure per procedure were collected from existing databases. Collective effective dose to the population and effective dose per capita were estimated from the collected data (DLP for CT, MGD for mammography and DAP for other procedures) using dose conversion factors. The total collective effective dose to the population from radiological in 2011 was estimated to 1300 manSv and an effective dose per capita to 0.6 mSv of which approximately 2/3 are due to CT procedures. The first systematic study of population exposure to ionising radiation from radiological procedures in Slovenia was performed. The results show that the exposure in Slovenia is under the European average. It confirmed large contributions of computed tomography and interventional procedures, identifying them as the areas that deserve special attention when it comes to justification and optimisation

  8. Intercomparison of iodine thyroid doses estimated for people living in urban and rural environments

    International Nuclear Information System (INIS)

    The radioecological model ECOSYS, developed in GSF-Institut fuer Strahlenschutz has been applied to calculate thyroid doses to the population due to I-131 exposures after the Chernobyl accident. The main contribution to the thyroid doses calculated is given by the consumption of milk and vegetables. Results are presented taking into account the different activity concentrations measured in milk of private family cows and mixed collective milk of a creamery in upper Bavaria, as well as different consumption behaviour of children and adults in rural and urban areas. Thyroid doses due to different milk consumption habits and a different milk origin in adults living in urban environments are estimated to be up to 12 times, in children up to 3 times lower than those estimated for rural environments. The dose contribution by vegetables, however, in any case exceeded the one by milk because of the high intake rates for the case investigated here. These values, however, may be overestimates for vegetables and have a very high uncertainty. For adults total thyroid dose by ingestion was higher in rural areas by a factor of 1.4, for children at the age of 10 years, total thyroid dose by ingestion was 1.5 times higher in urban environments for the conditions described here. (author)

  9. Estimate of the dose received in crystalline lens by pediatric interventional cardiologists

    International Nuclear Information System (INIS)

    The objective of this work is to estimate the maximum dose accumulated during one year in the crystalline lens of the pediatric interventional cardiologists that work in the Hospital Universitario La Paz. Optically Stimulated Luminescence Dosimeters (OSLDs) were used for to carry out this estimation, placed in the eyes of an anthropomorphic mannequin whose position in the room simulates the more habitual conditions of the clinical practice. Previously to the simulation, different tests to validate the used dosimetric system were realized, including those related with the stability, reproducibility and lector linearity, as well as the angular and energy dependence of the OSLDs. During the simulation the mannequin eyes were irradiated and were measured with OSLDs the rate of superficial equivalent dose in crystalline lens for the different qualities of beam habitually used, as much in fluoroscopy as in acquisition. With the obtained data during three years, corresponding to the fluoroscopy times and the acquisitions number of the interventional procedures carried out; as much therapeutic as diagnostic, and rate by measuring of obtained dose, has been considered the superficial equivalent dose and the equivalent dose at 3 mm deep accumulated in the crystalline lens of the pediatric interventional cardiologist with more work load of the Hospital, during the years 2011 and 2012. None of the obtained maximum values exceed the new dose annual limit in crystalline lens of 20 mSv, recommended by ICRP in April of 2011. (author)

  10. Estimation of radiation doses to patients and surgeons from various fluoroscopically guided orthopaedic surgeries

    International Nuclear Information System (INIS)

    In this study, a mathematical method was used to estimate the entrance surface dose (ESD) to the patient and the scattered dose (Ds) to the operating surgeon during various fluoroscopically guided surgical orthopaedic procedures. For 204 patients, the procedure type, the fluoroscopy time and the highest tube potential and current values observed during fluoroscopy were recorded. For the most often performed procedures (intramedullary nailing of peritrochanteric fractures, open reduction and internal fixation of malleolar fractures and intramedullary nailing of diaphyseal fractures of the femur), the respective mean fluoroscopy times were 3.2, 1.5 and 6.3 min while the estimated mean ESDs were 183, 21 and 331 mGy, respectively. The estimated Ds rates for the hands, chest, thyroid, eyes, gonads and legs of the operating surgeon were on average to 0.103, 0.023, 0.013, 0.012, 0.066 and 0.045 mGy min-1, respectively, and compare well with the literature. The mathematical estimation of doses cannot replace actual measurements; however, it can be used for a preliminary assessment of the radiation dose levels during various surgical procedures, so that the operator, the surgeon and the rest of the medical staff involved could be aware of the associated radiation risk and the radiation protection measures required. (authors)

  11. Research on the main factors of dose estimation influenced by autoradiography

    International Nuclear Information System (INIS)

    Objective: In most situations, the spatial locations of radiopharmaceuticals are not uniform, so that in order to estimate the dose to cells and cell nuclei is necessary. Methods: Auto-radio-graphy (ARG) is a method to obtain the precise spatial information of the (radio-labels, relative to the tissue histology. In the study, the microscopic locations of this) radioactive substance in the liver of mice were investigated through microscopic frozen section ARG, and a mathematical model was developed, which can be conveniently used to microdosimetry, such as estimations of the doses received by the cell nuclei in rat liver after injection of 99mTc-MIBI via tail veins in the test. Results: A comparison of the radiation dose rate estimates was conducted between the cellular dosimetry model and MIRD, revealing significant differences. Conclusion: ARG was proved to be a useful approach to provide detailed spatial and dosimetric information on radiopharmaceuticals within organs so that the authors can evaluate precisely the effectiveness of radiotherapy and radiotoxicity and microscopic radiation-effect in nuclear medicine. In the study the influence factors of dose estimation are detail analysed and discussed

  12. Monte Carlo estimation of photoneutrons spectra and dose equivalent around an 18 MV medical linear accelerator

    Science.gov (United States)

    Alem-Bezoubiri, A.; Bezoubiri, F.; Badreddine, A.; Mazrou, H.; Lounis-Mokrani, Z.

    2014-04-01

    A fully detailed Monte Carlo geometrical model of an 18 MV Varian Clinac 2100C medical linear accelerator, lodged at Blida Anti-Cancer Centre in Algeria, was developed during this study to estimate the photoneutrons spectra and doses at the patient table in a radiotherapy treatment room, for radiation protection purposes.

  13. Primate polonium metabolic models and their use in estimation of systemic radiation doses from bioassay data. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, N. [New York Univ. Medical Center, Tuxedo, NY (United States). Dept. of Environmental Medicine

    1989-03-15

    A Polonium metabolic model was derived and incorporated into a Fortran algorithm which estimates the systemic radiation dose from {sup 210}Po when applied to occupational urine bioassay data. The significance of the doses estimated are examined by defining the degree of uncertainty attached to them through comprehensive statistical testing procedures. Many parameters necessary for dosimetry calculations (such as organ partition coefficients and excretion fractions), were evaluated from metabolic studies of {sup 210}Po in non-human primates. Two tamarins and six baboons were injected intravenously with {sup 210}Po citrate. Excreta and blood samples were collected. Five of the baboons were sacrificed at times ranging from 1 day to 3 months post exposure. Complete necropsies were performed and all excreta and the majority of all skeletal and tissue samples were analyzed radiochemically for their {sup 210}Po content. The {sup 210}Po excretion rate in the baboon was more rapid than in the tamarin. The biological half-time of {sup 210}Po excretion in the baboon was approximately 15 days while in the tamarin, the {sup 210}Po excretion rate was in close agreement with the 50 day biological half-time predicted by ICRP 30. Excretion fractions of {sup 210}Po in the non-human primates were found to be markedly different from data reported elsewhere in other species, including man. A thorough review of the Po urinalysis procedure showed that significant recovery losses resulted when metabolized {sup 210}Po was deposited out of raw urine. Polonium-210 was found throughout the soft tissues of the baboon but not with the partition coefficients for liver, kidneys, and spleen that are predicted by the ICRP 30 metabolic model. A fractional distribution of 0.29 for liver, 0.07 for kidneys, and 0.006 for spleen was determined. Retention times for {sup 210}Po in tissues are described by single exponential functions with biological half-times ranging from 15 to 50 days.

  14. Predictive estimate of blood dose from external counting data preceding radioiodine therapy for thyroid cancer

    International Nuclear Information System (INIS)

    Bone marrow depression following 131I therapy for metastatic thyroid cancer can occur in up to one-quarter of all patients so treated. An analysis was made of the 131I whole body (WB) retention and its relationship to activity in blood for 46 patients (45 adult, 1 adolescent in 49 total studies) to define the accuracy of utilizing WB external counting data as a predictor of blood dose in comparison to the more classical method which requires data from sequential blood samples. The mean percentage differences between blood dose estimates based on external WB counting and those calculated by the classical method lie within ± 10%. The WB methodology provides a useful first-order approximation for hematopietic dose estimates in adult patients undergoing 131I therapy for thyroid cancer. (author)

  15. Estimation of exposed radiation dose in radiography of the chest. Mainly on the dose at health examination on automobiles

    International Nuclear Information System (INIS)

    The exposure doses in radiography and photofluorography of the chest at health examination on automobiles were estimated and compared with those using other hospital equipments. The tube voltage, effective energy and half value layer under ordinary conditions for radiography and fluorography were measured by KYOKKO model 100 X-ray analyzer and output pulse shape was confirmed by the fluorometer (TOREKEY-1001 C). The dose at the body surface was measured by the ionization chambers (VICTOREEN RADCON 500 and 30-330) which had been equipped in the WAC chest phantom (JIS Z 4915, Kyoto Kagaku). Nine automobiles of 3 facilities were used, of which X-ray generating apparatuses of either condenser or inverter type were manufactured by Hitachi (5 machines), Toshiba (1) and Shimadzu (3). The examined apparatuses not for the automobile were Toshiba-20 and Hitachi SIRIUS-100 portable ones and Hitachi DH-1520 TM high-voltage one. The effective energy was found dependent on the tube voltage (100-130 kV) and X-ray generating system (35.1-54.37 keV in the condenser type and 41.1-43.9 keV in the inverter type). Pulse shape analysis revealed that the pulse height and area under the pulse height-time curve were larger in the inverter system. The mean doses in photofluorography and radiography on automobiles were 0.525 and 0.297 mGy, respectively. The mean dose of 0.61 mGy in radiography at home with the portable apparatus was the highest even when compared with that of 0.525 mGy for fluorography on the automobile. Thus, the inverter system on the car can guarantee the level of 0.4 mGy defined by IAEA guideline (Safety series No. 115, 1996). (K.H.)

  16. In-flight dose estimates for military aircraft crew on transport missions

    International Nuclear Information System (INIS)

    Full text: Aircraft fighter pilots may experience risks other than the cosmic radiation exposure due to the characteristics of a typical fighter flight. The combined risks for fighter pilots due to the G-forces, hypobaric hypoxia, cosmic radiation exposure, etc. have determined that pregnant female pilots should remain on ground. However, several military transport missions can be considered an ordinary civil aircraft flight and the question arises whether the pregnant female pilot could be part of the aircrew. In this work the cosmic radiation dose received in several transport missions was estimated. Typical transport missions carried out in one month by a single air squad were considered. The flights departured from Lisbon to areas such as the Azores, to several countries in central and southern Africa, to the western coast of the USA and to the Balkans and an estimate of the cosmic radiation dose received on each flight was carried out. A monthly average cosmic radiation dose to the aircrew was determined and the dose values obtained were discussed in relation to the limits established by the European Union Council Directive 96/29/Euratom. The cosmic ray dose estimates were performed using the EPCARD v3.2 and the CARI-6 computing codes. EPCARD v3.2 was kindly made available by GSF-National Research Centre for Environment and Health, Institute of Radiation Protection (Neuherberg, Germany). CARI-6 (version July 7th, 2004) was downloaded from the web site of the Civil Aerospace Medical Institute, Federal Aviation Administration (USA). In this work an estimate of the cosmic radiation dose received by military aircraft crew on realistic typical transport missions is made. (author)

  17. Natural radionuclides in cigarette tobacco from Serbian market and effective dose estimate from smoke inhalation

    International Nuclear Information System (INIS)

    The activity concentrations of natural radionuclides (40K, 210Pb, 210Po, 226Ra and 228Ra) in 17 most frequently used cigarette brands in Serbia and corresponding effective doses due to smoke inhalation are presented. The mean annual effective doses for 210Pb and 210Po were estimated to be 47.3 and 724 μSv y-1 for 210Pb and 210Po, respectively. Serbia currently has the highest smoking rate in the world. The results of this study indicate the high contribution of the annual effective dose due to smoke inhalation to the total inhalation dose from natural radionuclides. The more effective implementation of actions for reducing smoking prevalence in Serbia is highly needed. (authors)

  18. Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams

    International Nuclear Information System (INIS)

    Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 γ-ray beams. Either the Klein--Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source--surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm

  19. Dose estimates for patients receiving radiation from various instruments used for measuring bone mass and density

    International Nuclear Information System (INIS)

    The patient dose from in vivo measurement of bone mass and density was estimated by a phantom method. The measurement methods studied were microdensitometry (MD method), single photon absorptiometry (SPA), dual energy X ray absorptiometry (DEXA), quantitative computed tomography (QCT) and conventional X-ray photography (X-P) for vertebrae, all of which have been used for mass screening or clinical examination of osteoporosis. The organ absorbed doses from the QCT and X ray photography were several mSv and these values were one to two orders of magnitude higher than those from the DEXA method. The effective dose and entrance skin dose from the QCT and X ray photography were one to two orders of magnitude higher than the DEXA, which were μSv and some ten μSv, respectively. The application of X-P and QCT for a young population should be carefully judged. (author)

  20. SU-E-T-238: Monte Carlo Estimation of Cerenkov Dose for Photo-Dynamic Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chibani, O; Price, R; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Eldib, A [Fox Chase Cancer Center, Philadelphia, PA (United States); University Cairo (Egypt); Mora, G [de Lisboa, Codex, Lisboa (Portugal)

    2014-06-01

    Purpose: Estimation of Cerenkov dose from high-energy megavoltage photon and electron beams in tissue and its impact on the radiosensitization using Protoporphyrine IX (PpIX) for tumor targeting enhancement in radiotherapy. Methods: The GEPTS Monte Carlo code is used to generate dose distributions from 18MV Varian photon beam and generic high-energy (45-MV) photon and (45-MeV) electron beams in a voxel-based tissueequivalent phantom. In addition to calculating the ionization dose, the code scores Cerenkov energy released in the wavelength range 375–425 nm corresponding to the pick of the PpIX absorption spectrum (Fig. 1) using the Frank-Tamm formula. Results: The simulations shows that the produced Cerenkov dose suitable for activating PpIX is 4000 to 5500 times lower than the overall radiation dose for all considered beams (18MV, 45 MV and 45 MeV). These results were contradictory to the recent experimental studies by Axelsson et al. (Med. Phys. 38 (2011) p 4127), where Cerenkov dose was reported to be only two orders of magnitude lower than the radiation dose. Note that our simulation results can be corroborated by a simple model where the Frank and Tamm formula is applied for electrons with 2 MeV/cm stopping power generating Cerenkov photons in the 375–425 nm range and assuming these photons have less than 1mm penetration in tissue. Conclusion: The Cerenkov dose generated by high-energy photon and electron beams may produce minimal clinical effect in comparison with the photon fluence (or dose) commonly used for photo-dynamic therapy. At the present time, it is unclear whether Cerenkov radiation is a significant contributor to the recently observed tumor regression for patients receiving radiotherapy and PpIX versus patients receiving radiotherapy only. The ongoing study will include animal experimentation and investigation of dose rate effects on PpIX response.

  1. SU-E-T-238: Monte Carlo Estimation of Cerenkov Dose for Photo-Dynamic Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: Estimation of Cerenkov dose from high-energy megavoltage photon and electron beams in tissue and its impact on the radiosensitization using Protoporphyrine IX (PpIX) for tumor targeting enhancement in radiotherapy. Methods: The GEPTS Monte Carlo code is used to generate dose distributions from 18MV Varian photon beam and generic high-energy (45-MV) photon and (45-MeV) electron beams in a voxel-based tissueequivalent phantom. In addition to calculating the ionization dose, the code scores Cerenkov energy released in the wavelength range 375–425 nm corresponding to the pick of the PpIX absorption spectrum (Fig. 1) using the Frank-Tamm formula. Results: The simulations shows that the produced Cerenkov dose suitable for activating PpIX is 4000 to 5500 times lower than the overall radiation dose for all considered beams (18MV, 45 MV and 45 MeV). These results were contradictory to the recent experimental studies by Axelsson et al. (Med. Phys. 38 (2011) p 4127), where Cerenkov dose was reported to be only two orders of magnitude lower than the radiation dose. Note that our simulation results can be corroborated by a simple model where the Frank and Tamm formula is applied for electrons with 2 MeV/cm stopping power generating Cerenkov photons in the 375–425 nm range and assuming these photons have less than 1mm penetration in tissue. Conclusion: The Cerenkov dose generated by high-energy photon and electron beams may produce minimal clinical effect in comparison with the photon fluence (or dose) commonly used for photo-dynamic therapy. At the present time, it is unclear whether Cerenkov radiation is a significant contributor to the recently observed tumor regression for patients receiving radiotherapy and PpIX versus patients receiving radiotherapy only. The ongoing study will include animal experimentation and investigation of dose rate effects on PpIX response

  2. Radiation doses and estimated risk from angiographic projections during coronary angiography performed using novel flat detector.

    Science.gov (United States)

    Varghese, Anna; Livingstone, Roshan S; Varghese, Lijo; Kumar, Parveen; Srinath, Sirish Chandra; George, Oommen K; George, Paul V

    2016-01-01

    Coronary angiography (CA) procedure uses various angiographic projections to elicit detailed information of the coronary arteries with some steep projections involving high radiation dose to patients. This study intends to evaluate radiation doses and estimated risk from angiographic projections during CA procedure performed using novel flat detector (FD) system with improved image processing and noise reduction techniques. Real-time monitoring of radiation doses using kerma-area product (KAP) meter was performed for 140 patients using Philips Clarity FD system. The CA procedure involved seven standard projections, of which five were extensively selected by interventionalists. Mean fluoroscopic time (FT), KAP, and reference air kerma (Ka,r) for CA procedure were 3.24 min (0.5-10.51), 13.99Gycm2 (4.02-37.6), and 231.43 mGy (73.8-622.15), respectively. Effective dose calculated using Monte Carlo-based PCXMC software was found to be 4.9mSv. Left anterior oblique (LAO) 45° projection contributed the highest radiation dose (28%) of the overall KAP. Radiation-induced risk was found to be higher in females compared to males with increased risk of lung cancer. An increase of 10%-15% in radiation dose was observed when one or more additional projections were adopted along with the seven standard projections. A 14% reduction of radiation dose was achieved from novel FD system when low-dose protocol during fluoroscopy and medium-dose protocol during cine acquisitions were adopted, compared to medium-dose protocol. PMID:27167263

  3. Low-dose neutron dose response of zebrafish embryos obtained from the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility

    International Nuclear Information System (INIS)

    The dose response of embryos of the zebrafish, Danio rerio, irradiated at 5 h post fertilization (hpf) by 2-MeV neutrons with ≤100 mGy was determined. The neutron irradiations were made at the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility in the National Institute of Radiological Sciences (NIRS), Chiba, Japan. A total of 10 neutron doses ranging from 0.6 to 100 mGy were employed (with a gamma-ray contribution of 14% to the total dose), and the biological effects were studied through quantification of apoptosis at 25 hpf. The responses for neutron doses of 10, 20, 25, and 50 mGy approximately fitted on a straight line, while those for neutron doses of 0.6, 1 and 2.5 mGy exhibited neutron hormetic effects. As such, hormetic responses were generically developed by different kinds of ionizing radiations with different linear energy transfer (LET) values. The responses for neutron doses of 70 and 100 mGy were significantly below the lower 95% confidence band of the best-fit line, which strongly suggested the presence of gamma-ray hormesis. - Highlights: • Neutron dose response was determined for embryos of the zebrafish, Danio rerio. • Neutron doses of 0.6, 1 and 2.5 mGy led to neutron hormetic effects. • Neutron doses of 70 and 100 mGy accompanied by gamma rays led to gamma-ray hormesis

  4. Late biological effects of ionizing radiation as influenced by dose, dose rate, age at exposure and genetic sensitivity to neoplastic transformation

    International Nuclear Information System (INIS)

    A most comprehensive investigation is in progress at the Los Alamos Scientific Laboratory to study the late biological effects of whole-body exposure to gamma irradiation as they may be influenced by total dose, dose rate, age at exposure and genetic background. Strain C57B1/6J mice of four age groups (newborn, 2, 6 and l5 months) were given five doses (20, 60, 180, 540, and 1620 rads) of gamma rays, with each dose being delivered at six dose rates (0.7, 2.1, 6.3, 18.9, 56.7 rads/day and 25 rads/min). Forty to sixty mice were used in each of the approximately 119 dose/dose-rate and age combinations. The study was done in two replications with an equal number of mice per replicaton. Strain RF/J mice were used in a companion study to investigate the influence of genetic background on the type and magnitude of effect. Results of the first and second replications of the l5-month-old age group and data on the influence of genetic background on biological response have been completed, and the results show no significant life shortening within the dose and dose-rate range used. It was also concluded that radiaton-induced neoplastic transformaton was significantly greater in mice with a known genetic sensitivity to neoplastic disease than in mammals which do not normally have a significant incidence of tumours. (author)

  5. Estimating the radiation dose of patient in cardiovascular disease interventional procedures

    International Nuclear Information System (INIS)

    Nuclear and radiation technology have a breakthrough development in the application of medical clinics. Some new radiological diagnosis and radiotherapy technologies have brought tremendous interest for human. Radiological intervention is the most representative of this type of radiation therapy technology. Large doses can cause possible skin and eye lens radiation damage, and is one of the most difficult occupational radiation protection. Because about 60 percent of surgical intervention is used in the treatment of cardiovascular diseases, the issue of radiation protection of patients in cardiovascular interventional has aroused widely attention both at home and abroad and carried out more extensive research. A large number of studies have shown that, cardiovascular intervention may cause high exposure doses to the patients that should be paid more attention. Surface dose is not enough to evaluate how much risk the patients suffering. When the human body suffer strongly penetrating power of radiation (X ray, γ ray, neutron) and the dose achieve a certain quantity, deep tissue and organ damage will happen. So when studying the surface dose, it is important to research the dose of the tissues and organs. Radiation intervention can result in stochastic effects such as oncology and genetic damage, therefore it is necessary to estimate the effective dose. (authors)

  6. Estimation of effective dose during hystrosalpingography procedures in certain hospitals in Sudan

    International Nuclear Information System (INIS)

    The aims of this study were to measure the patients’ entrance surface air kerma doses (ESAK), effective doses and to compare practices between different hospitals in Sudan. ESAK were measured for patient using calibrated thermo luminance dosimeters (TLDs, GR200A). Effective doses were estimated using National radiological Protection Board (NRPB) software. This study was conducted in five radiological departments: Two Teaching Hospitals (A and D), two private hospitals (B and C) and one University Hospital (E). The mean ESAK was 20.1 mGy, 28.9 mGy, 13.6 mGy, 17.5 mGy, 35.7 mGy for hospitals A, B, C, D, and E, respectively. The mean effective dose was 2.4 mSv, 3.5 mSv, 1.6 mSv, 2.1 mSv and 4.3 mSv in the same order. The study showed wide variations in the ESDs with three of the hospitals having values above the internationally reported values. - Highlights: • Radiation dose was made for females in child bearing age undergoing HSG procedure. • Radiation doses were measured using calibrated TLD GR200A. • The study revealed the urgent need for dose reduction techniques. • Adoption of quality control measures may help to limit variations which are due to equipment related factors

  7. Estimated Fluoride Doses from Toothpastes Should be Based on Total Soluble Fluoride

    Directory of Open Access Journals (Sweden)

    Jaime A. Cury

    2013-11-01

    Full Text Available The fluoride dose ingested by young children may be overestimated if based on levels of total fluoride (TF rather than levels of bioavailable fluoride (total soluble fluoride—TSF in toothpaste. The aim of the present study was to compare doses of fluoride intake based on TF and TSF. Fluoride intake in 158 Brazilian children aged three and four years was determined after tooth brushing with their usual toothpaste (either family toothpaste (n = 80 or children’s toothpaste (n = 78. The estimated dose (mg F/day/Kg of body weight of TF or TSF ingested was calculated from the chemical analysis of the toothpastes. Although the ingested dose of TF from the family toothpastes was higher than that from the children’s toothpastes (0.074 ± 0.007 and 0.039 ± 0.003 mg F/day/Kg, respectively; p 0.05. The fluoride dose ingested by children from toothpastes may be overestimated if based on the TF of the product. This finding suggests that the ingested dose should be calculated based on TSF. Dose of TSF ingested by children is similar whether family or children’s toothpaste is used.

  8. Methods used to estimate the collective dose in Denmark from diagnostic radiology

    International Nuclear Information System (INIS)

    According to EU directive 97/43/Euratom all member states must estimate doses to the public from diagnostic radiology. In Denmark the National Institute of Radiation Hygiene (NIRH) is about to finish a project with the purpose of estimating the collective dose in Denmark from diagnostic radiology. In this paper methods, problems and preliminary results will be presented. Patient doses were obtained from x-ray departments, dentist and chiropractors. Information about the frequencies of examination was collected from each of the Danish hospitals or counties. It was possible to collect information for nearly all of the hospitals. The measurements were done by means of dose area product meters in x-ray departments and by thermoluminescent dosimetry at chiropractors and solid-sate detectors at dentists. Twenty hospitals, 3,200 patients and 23,000 radiographs were measured in this study. All data were stored in a database for quick retrieval. The DAP (Dose Area Product) measurements was done 'automatically' controlled by PC based software. Later these recordings could be analysed by means of specially designed software and transferred to the database. Data from the chiropractors were obtained by mail. NIRH sent each chiropractor TLD's and registration form. The chiropractor did the measurements him self and returned afterwards the TLD's and registration forms. On the registration form height, weight, age etc. of the patient was noted and so was information about applied high-tension, current-time product and projection. Calculation of the effective dose from the DAP values and the surface entrance dose were done by Monte Carlo techniques. For each radiographs two pictures of the mathematical phantom were generated to ensure that the x-ray field where properly placed. The program 'diagnostic dose' developed by NIRH did the Monte Carlo calculations. (author)

  9. Estimate of return periods for enhanced gamma ray dose rates due to precipitation

    International Nuclear Information System (INIS)

    In order to contribute for the establishment of criteria whether the high level of gamma (γ) ray dose rate is an unusual value, statistical analysis for its frequency distribution was carried out. The γ ray dose rates monitored at six sites (Minamihoroni, Kariwa, Wajima, Asahikawa, Ohno, and Tokai-mura Oshinobe) in Japan during the periods from 2000 to 2004 were subjected to the analysis. The γ ray dose rates were not normally distributed but the distribution distorted to higher side. Our statistical analysis suggests that the γ ray dose rates above 'average + 3σ' or '100nGy/h', which are the conventional definition, occurred frequently. Here we propose the use of more suitable method to detect the unusual value of the enhanced γ ray dose rates on the basis of the 'return period'. It is the recurrence frequency of high γ ray dose rates. Estimate of the return periods, which is usually used for the extreme event of meteorology, is given for the first time in this field. In this study, we compared two methods to calculate the return periods: empirical return period (TH) based on Hazen plot by using the enhanced γ ray dose rates and theoretical estimated return period (TG) based on Gumbel distribution by using average and standard deviation of the enhanced γ ray dose rates. There were significant difference of TH as well as TG between monitoring sites. It turned out that the judgement of an unusual value must be considered based on TH and TG at each monitoring site. (author)

  10. Estimation of Ga-67 radiation dose to a breast-fed infant

    International Nuclear Information System (INIS)

    Full text: The quality assurance programs for the practice of nuclear medicine in Colombia include optimization of public exposure by the radioactive sources used in medical diagnosis and treatment. Precautionary measures notwithstanding, occasionally members of the public receive doses larger than expected; usually there is no direct data to evaluate dose. We briefly describe the process to estimate the radiation dose absorbed by a 5-month-old baby that was inadvertently breast-fed for 48 hours by his 22-year-old mother that was administered 296 MBq of radioactive Ga-67 citrate. After the intravenous administration, the Ga-67 is commonly observed in the intestine, and other organs, and in the breasts of lactating women, thus possibly leading to radiation exposure of the infant's lower intestine. We had 256x256 single photon emission computed tomography (SPECT) images, and whole-body 1024 x 256 planar images, taken 48h and 72 h after Ga-67 intake. The images were obtained with a Siemens E-cam gamma camera, a 20% energy window was placed at the 93, 184 and 296 keV gamma photopeaks. From these images we calculated the concentration of Ga-67 in mother's milk (using Medical Internal Radiation Dose MIRD methodology). Hence, the dose absorbed by the baby. The radioactivity in breast milk per liter was 4% of the injected activity. The dose absorbed by the infant's lower intestine was 11 mGy. The effective dose to the infant was estimated as 7 mSv, which is above the annual limit to the general public (1 mSv/year). Hence, an infant breast-fed by a mother undergoing Ga-67 treatment may easily receive a radiation dose in excess of the annual upper limit. From the viewpoint of radiation protection it is extremely important to convey to the mother the necessity of abiding by the standard medical recommendation of discontinuing breast feeding for at least 2 weeks after Ga-67 intake. (author)

  11. The accuracy of absorbed dose estimates in tumours determined by Quantitative SPECT: A Monte Carlo study

    International Nuclear Information System (INIS)

    Background. Dosimetry in radionuclide therapy estimates delivered absorbed doses to tumours and ensures that absorbed dose levels to normal organs are below tolerance levels. One procedure is to determine time-activity curves in volumes-of-interests from which the absorbed dose is estimated using SPECT with appropriate corrections for attenuation, scatter and collimator response. From corrected SPECT images the absorbed energy can be calculated by (a) assuming kinetic energy deposited in the same voxel where particles were emitted, (b) convolve with point-dose kernels or (c) use full Monte Carlo (MC) methods. A question arises which dosimetry method is optimal given the limitations in reconstruction- and quantification procedures. Methods. Dosimetry methods (a) and (c) were evaluated by comparing dose-rate volume histograms (DrVHs) from simulated SPECT of 111In, 177Lu, 131I and Bremsstrahlung from 90Y to match true dose rate images. The study used a voxel-based phantom with different tumours in the liver. SPECT reconstruction was made using an iterative OSEM method and MC dosimetry was performed using a charged-particle EGS4 program that also was used to determined true absorbed dose rate distributions for the same phantom geometry but without camera limitations. Results. The DrVHs obtained from SPECT differed from true DrVH mainly due to limited spatial resolution. MC dosimetry had a marginal effect because the SPECT spatial resolution is in the same order as the energy distribution caused by the electron track ranges. For 131I, full MC dosimetry made a difference due to the additional contribution from high-energy photons. SPECT-based DrVHs differ significantly from true DrVHs unless the tumours are considerable larger than the spatial resolution. Conclusion. It is important to understand limitations in quantitative SPECT images and the reasons for apparent heterogeneities since these have an impact on dose-volume histograms. A MC-based dosimetry calculation from

  12. Estimation of patient exposure dose in the X-ray diagnoses

    International Nuclear Information System (INIS)

    Fundamental concept to asses the patient dose and its calculating methods are explained for X-ray examinations like radiography, abdominal fluoroscopy and CT, from the technological aspect of radiological protection. Justification of medical exposure, optimization of its dose and assessment of absorbed dose in patients are essentially based on guides by ICRP, IAEA and ICRU, and their application to Japanese standard has been being conducted. The numerical dose determination (NDD) method has been widely used by calculating the patient entrance air kerma using parameters of the tube voltage, tube current-time product, distance from the focus to skin, total filtration and back scatter. Coefficients for NDD are obtained from the tube voltage and Al filtration of X-ray spectrum with an empirical formula. The add-in software (NDD-Modify) in MS-Excel later developed can conveniently give the rough patient dose and is utilized in such facilities as having no dosimeter. radiology information system (RIS) equipped in the X-ray machine displays the estimated patient dose by NDD base and the actual output dose before and after imaging, respectively. This NDD comes from standardized coefficients of parameters above for 5 x 5-30 x 30 cm irradiation sizes using their corresponding back scatter coefficients calculated by Monte Carlo techniques for modeled structures of the tube, multi-leaf diaphragm and water phantom, and has been also able to be applied in the personal computer (PC) with the software estimation of patient dose (EPD). The PC-based Monte Carlo program for calculating organ doses of patients undergoing medical X-ray examinations (PCXMC) of radiology and fluoroscopy is written with Delphi Object Pascal code; is composed from the photoelectric absorption, coherent and incoherent scatters; and widely used at present. imaging performance assessment of CT scanners (ImPACT) is the excel bookfile, usable to calculate the organ dose and effective dose. In future, patient

  13. Contribution of the modulation of intensity and the optimization to deliver a dose adapted to the biological heterogeneities; Apport de la modulation d'intensite et de l'optimisation pour delivrer une dose adaptee aux heterogeneites biologiques

    Energy Technology Data Exchange (ETDEWEB)

    Kubs, F

    2007-10-15

    The recent progress in functional imaging by Positron Emission Tomography (TEP) opens new perspectives in the delineation of target volumes in radiotherapy. The functional data is major; we can intend to adapt the irradiation doses on the tumor activity (TA) and to perform a dose escalation. Our objectives were (i) to characterize the TEP threshold, by quantifying the uncertainties of the target volume contour according to the lesion size and the threshold contour level, (ii) to set up the geometry suited to perform a high-precision irradiation based on the TA, (iii) to estimate the dosimetric impact of this new protocol and (iv) to verify that dosimetry is perfectly distributed. Three original phantoms were specially created to satisfy the constraints met, as well as two virtual phantoms containing 3 dose levels (dose level 3 = TA). Our results showed the importance of the effect threshold-volume on the planning in radiotherapy. To use this irradiation method, the diameter of 1 cm for the third level was able to be reached. A dose escalation of 20 Gy was possible between the second (70 Gy) and the third level (90 Gy). The dosimetric impact estimated on two real cases was suitable - increase of COIN (conformal index) from 0.6 to 0.8 and decrease of NTCP (normal tissue complication probability) of a factor 5 -. In absolute and relative dosimetry, the clinical tolerances were respected. So all the treatment process, going from the diagnosis with the TEP to reveal the TA, to the patient treatment made beforehand on phantom, and going through the ballistic and the dose calculation, was estimated and validated according to our objective to adapt the irradiation to the biological heterogeneities. However such high doses should be carefully estimated before being prescribed clinically and progress is also expected in imaging, because the minimal size which we can irradiate is on the limit of the resolution TEP. (author)

  14. Application of laboratory sourceless object counting for the estimation of the neutron dose

    International Nuclear Information System (INIS)

    Objective: To estimate the neutron dose using 24Na energy spectrum analysis method. Methods: Genius-2000 GeomComposer software package was used to calibrate the efficiency of the detector. Results: The detection efficiency of the detector toward γ photon with an energy of 1.368 MeV was quickly found to be 4.05271×10-3 while the error of the software was 4.0% . The estimated dose value of the neutron irradiation samples was between 1.94 Gy and 2.82 Gy, with an arithmetic mean value of 2.38 Gy. The uncertainty of the dosimetry was about 20.07% . Conclusion: The application of efficiency calibration without a radioactive source of the energy spectrum analysis of the 24Na contained in human blood with accelerate the estimation process. (authors)

  15. Absorbed dose and biologically effective dose in patients with high-risk non-Hodgkin's lymphoma treated with high-activity myeloablative {sup 90}Y-ibritumomab tiuxetan (Zevalin registered)

    Energy Technology Data Exchange (ETDEWEB)

    Chiesa, C.; Coliva, A.; Maccauro, M.; Seregni, E.; Bombardieri, E. [Foundation IRCCS Istituto Nazionale Tumori, Nuclear Medicine Division, Milan (Italy); Botta, F. [University of Milan, Health Physics Postgraduate School, Milan (Italy); Devizzi, L.; Guidetti, A. [Foundation IRCCS Istituto Nazionale Tumori, ' ' Cristina Gandini' ' Medical Oncology, Milan (Italy); Carlo-Stella, C.; Gianni, M.A. [Foundation IRCCS Istituto Nazionale Tumori, ' ' Cristina Gandini' ' Medical Oncology, Milan (Italy); University of Milan, Medical Oncology, Milan (Italy)

    2009-11-15

    The aim of this study was to carry out two different dose estimation approaches in patients with non-Hodgkin's lymphoma (NHL) treated with a myeloablative amount of {sup 90}Y-labelled ibritumomab tiuxetan (Zevalin registered) in an open-label dose escalation study. Twenty-seven patients with relapsed/refractory or de novo high-risk NHL receiving one myeloablative dose of {sup 90}Y-ibritumomab tiuxetan followed by tandem stem cell reinfusion were evaluated for dose estimate. The injected activity was 30 MBq/kg in 12 patients and 45 MBq/kg in 15 patients. Dose estimation was performed 1 week prior to {sup 90}Y-ibritumomab tiuxetan by injection of {sup 111}In-ibritumomab tiuxetan (median activity: 200 MBq). The absorbed dose (D) and the biologically effective dose (BED) were calculated. The absorbed doses per unit activity (Gy/GBq) were [median (range)]: heart wall 4.6 (2.5-9.7), kidneys 5.1 (2.8-10.5), liver 6.1 (3.9-10.4), lungs 2.9 (1.5-6.8), red marrow 1.0 (0.5-1.7), spleen 7.0 (1.5-14.4) and testes 4.9 (2.9-16.7). The absorbed dose (Gy) for the 15 patients treated with 45 MBq/kg were: heart wall 17.0 (8.7-25.4), kidneys 17.1 (7.9-22.4), liver 20.8 (15.4-28.3), lungs 8.1 (5.4-11.4), red marrow 3.1 (2.0-4.0), spleen 26.2 (17.0-35.6) and testes 17.3 (9.0-28.4). At the highest activities the acute haematological toxicity was mild or moderate and of very short duration, and it was independent of the red marrow absorbed dose. No secondary malignancy or treatment-related myelodysplastic syndrome was observed. No non-haematological toxicity (liver, kidney, lung) was observed during a follow-up period of 24-48 months. The use of 45 MBq/kg of {sup 90}Y-ibritumomab tiuxetan in association with stem cell autografting resulted in patients being free of toxicity in non-haematological organs. These clinical findings were in complete agreement with our dose estimations, considering both organ doses and BED values. (orig.)

  16. The debate about effects of low doses: from epidemiology to biology

    International Nuclear Information System (INIS)

    The validity of the linear no-threshold dose-carcinogenic effect relationship used in radio protection was called into question by the discovery during the past 15 years of three cell mechanisms for protection of the genome: antioxidant systems that react to oxidative stress, DNA repair, and elimination by death of cells with damaged DNA, either when the DNA repair mechanisms were not activated because of the very low dose (or dose rate) or by apoptosis for higher doses because the DNA damage was not appropriately repaired. It is now clear that these mechanisms are more effective for low closes (<100 mSv) than for doses exceeding several hundred mSv, therefore the biological data are no longer compatible with the hypothesis of a linear no-threshold relationship (LNT). This conclusion is consistent with the experimental (both in vivo and in vitro) and epidemiologic data, which reveal no harmful effects for doses less than approximately 100 mSv. Accordingly, the principal conclusion that has been drawn from the LNT, that is, that any close, however low, is carcinogenic, is called into question because it no longer has a scientific basis. This dogma, which has been extended to all carcinogenic agents, causes diffuse anxiety in all those exposed to carcinogenic agents, even at very low concentrations. It has led to the refusal of some to submit to radiologic examinations (such as mammographic screening for breast cancer), with sometimes regrettable medical consequences. After the Chernobyl catastrophe it caused panic and the evacuation of vast territories where natural irradiation was only very slightly increased, with social and medical consequences due to displacement of more than 200,000 people. It is therefore urgent to reconsider it. (author)

  17. Environmental radioactivity in the UK: the airborne geophysical view of dose rate estimates

    International Nuclear Information System (INIS)

    This study considers UK airborne gamma-ray data obtained through a series of high spatial resolution, low altitude surveys over the past decade. The ground concentrations of the naturally occurring radionuclides Potassium, Thorium and Uranium are converted to air absorbed dose rates and these are used to assess terrestrial exposure levels from both natural and technologically enhanced sources. The high resolution airborne information is also assessed alongside existing knowledge from soil sampling and ground-based measurements of exposure levels. The surveys have sampled an extensive number of the UK lithological bedrock formations and the statistical information provides examples of low dose rate lithologies (the formations that characterise much of southern England) to the highest sustained values associated with granitic terrains. The maximum dose rates (e.g. >300 nGy h−1) encountered across the sampled granitic terrains are found to vary by a factor of 2. Excluding granitic terrains, the most spatially extensive dose rates (>50 nGy h−1) are found in association with the Mercia Mudstone Group (Triassic argillaceous mudstones) of eastern England. Geological associations between high dose rate and high radon values are also noted. Recent studies of the datasets have revealed the extent of source rock (i.e. bedrock) flux attenuation by soil moisture in conjunction with the density and porosity of the temperate latitude soils found in the UK. The presence or absence of soil cover (and associated presence or absence of attenuation) appears to account for a range of localised variations in the exposure levels encountered. The hypothesis is supported by a study of an extensive combined data set of dose rates obtained from soil sampling and by airborne geophysical survey. With no attenuation factors applied, except those intrinsic to the airborne estimates, a bias to high values of between 10 and 15 nGy h−1 is observed in the soil data. A wide range of

  18. Effects of the loss of correlation structure on Phase 1 dose estimates

    International Nuclear Information System (INIS)

    In Phase I of the Hanford Environmental Dose Reconstruction Project, a step-by-step (modular) calculational structure was used. This structure was intended (1) to simplify the computational process, (2) to allow storage of intermediate calculations for later analyses, and (3) to guide the collection of data by presenting understandable structures for its use. The implementation of this modular structure resulted in the loss of correlation among inputs and outputs of the code, resulting in less accurate dose estimates than anticipated. The study documented in this report investigated two types of correlations in the Phase I model: temporal and pathway. Temporal correlations occur in the simulation when, in the calculation, data estimated for a previous time are used in a subsequent calculation. If the various portions of the calculation do not use the same realization of the earlier estimate, they are no longer correlated with respect to time. Similarly, spatial correlations occur in a simulation when, in the calculation, data estimated for a particular location are used in estimates for other locations. If the various calculations do not use the same value for the original location, they are no longer correlated with respect to location. The loss of the correlation structure in the Phase I code resulted in dose estimates that are biased. It is recommended that the air pathway dose model be restructured and the intermediate histograms eliminated. While the restructured code may still contain distinct modules, all input parameters to each module and all out put from each module should be retained in a database such that subsequent modules can access all the information necessary to retain the correlation structure

  19. Prospective estimation of organ dose in CT under tube current modulation

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Xiaoyu, E-mail: xt3@duke.edu [Department of Biomedical Engineering, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Li, Xiang [Department of Physics, Cleveland State University, Cleveland, Ohio 44115 (United States); Segars, W. Paul [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Frush, Donald P. [Division of Pediatric Radiology, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States); Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Departments of Physics and Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27705 (United States)

    2015-04-15

    Purpose: Computed tomography (CT) has been widely used worldwide as a tool for medical diagnosis and imaging. However, despite its significant clinical benefits, CT radiation dose at the population level has become a subject of public attention and concern. In this light, optimizing radiation dose has become a core responsibility for the CT community. As a fundamental step to manage and optimize dose, it may be beneficial to have accurate and prospective knowledge about the radiation dose for an individual patient. In this study, the authors developed a framework to prospectively estimate organ dose for chest and abdominopelvic CT exams under tube current modulation (TCM). Methods: The organ dose is mainly dependent on two key factors: patient anatomy and irradiation field. A prediction process was developed to accurately model both factors. To model the anatomical diversity and complexity in the patient population, the authors used a previously developed library of computational phantoms with broad distributions of sizes, ages, and genders. A selected clinical patient, represented by a computational phantom in the study, was optimally matched with another computational phantom in the library to obtain a representation of the patient’s anatomy. To model the irradiation field, a previously validated Monte Carlo program was used to model CT scanner systems. The tube current profiles were modeled using a ray-tracing program as previously reported that theoretically emulated the variability of modulation profiles from major CT machine manufacturers Li et al., [Phys. Med. Biol. 59, 4525–4548 (2014)]. The prediction of organ dose was achieved using the following process: (1) CTDI{sub vol}-normalized-organ dose coefficients (h{sub organ}) for fixed tube current were first estimated as the prediction basis for the computational phantoms; (2) each computation phantom, regarded as a clinical patient, was optimally matched with one computational phantom in the library; (3

  20. Biological stress response terminology: Integrating the concepts of adaptive response and preconditioning stress within a hormetic dose-response framework

    International Nuclear Information System (INIS)

    Many biological subdisciplines that regularly assess dose-response relationships have identified an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to a moderate to severe level of stress. Due to a lack of frequent interaction among scientists in these many areas, there has emerged a broad range of terms that describe such dose-response relationships. This situation has become problematic because the different terms describe a family of similar biological responses (e.g., adaptive response, preconditioning, hormesis), adversely affecting interdisciplinary communication, and possibly even obscuring generalizable features and central biological concepts. With support from scientists in a broad range of disciplines, this article offers a set of recommendations we believe can achieve greater conceptual harmony in dose-response terminology, as well as better understanding and communication across the broad spectrum of biological disciplines

  1. Estimation of the uncertainty in internal dose calculation for two contamination cases

    International Nuclear Information System (INIS)

    Full text: The result of dosimetric expertise after internal contamination is usually presented as a 'best estimate' calculated from the available monitoring data and information about the conditions of exposure. Reference assumptions are applied to make up for unknown parameter values. However, previous intercomparisons demonstrated that the evaluation of internal dose is subject to a large uncertainty coming from both the technical limits of measuring apparatus and the assumptions made by the expert. In this work we propose an alternative approach to the assessment of internal dose that enables to report the confidence interval associated with the evaluated dose value. So far, four sources of uncertainties on input data have been considered: the physicochemical characteristics of the radioactive material (absorption type and diameter of aerosols), the time pattern of intake, the counting error and the stochastic variability of excretion or bioassay sampling. Three successive steps of approximation are suggested, depending on the expected level of dose, for which increasingly realistic parameter values should be sought and applied. The propagation of errors from input data to dose result is performed through Monte Carlo calculation. Finally, the results of dose calculation are presented in the form of mean possible dose value, medium possible dose value and upper 95th percentile. This approach has been implemented in internal dose calculation softwares and applied to two example cases of routine monitoring of uranium and special monitoring of caesium. It provides a useful tool for both reporting the results of expertise and designing realistic monitoring programs, and it will be improved in the future by further investigation of the sources of uncertainty in internal dosimetry. (author)

  2. GLODEP2: a computer model for estimating gamma dose due to worldwide fallout of radioactive debris

    International Nuclear Information System (INIS)

    The GLODEP2 computer code provides estimates of the surface deposition of worldwide radioactivity and the gamma-ray dose to man from intermediate and long-term fallout. The code is based on empirical models derived primarily from injection-deposition experience gained from the US and USSR nuclear tests in 1958. Under the assumption that a nuclear power facility is destroyed and that its debris behaves in the same manner as the radioactive cloud produced by the nuclear weapon that attached the facility, predictions are made for the gamma does from this source of radioactivity. As a comparison study the gamma dose due to the atmospheric nuclear tests from the period of 1951 to 1962 has been computed. The computed and measured values from Grove, UK and Chiba, Japan agree to within a few percent. The global deposition of radioactivity and resultant gamma dose from a hypothetical strategic nuclear exchange between the US and the USSR is reported. Of the assumed 5300 Mton in the exchange, 2031 Mton of radioactive debris is injected in the atmosphere. The highest estimated average whole body total integrated dose over 50 years (assuming no reduction by sheltering or weathering) is 23 rem in the 30 to 50 degree latitude band. If the attack included a 100 GW(e) nuclear power industry as targets in the US, this dose is increased to 84.6 rem. Hotspots due to rainfall could increase these values by factors of 10 to 50

  3. GLODEP2: a computer model for estimating gamma dose due to worldwide fallout of radioactive debris

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, L.L.; Harvey, T.F.; Peterson, K.R.

    1984-03-01

    The GLODEP2 computer code provides estimates of the surface deposition of worldwide radioactivity and the gamma-ray dose to man from intermediate and long-term fallout. The code is based on empirical models derived primarily from injection-deposition experience gained from the US and USSR nuclear tests in 1958. Under the assumption that a nuclear power facility is destroyed and that its debris behaves in the same manner as the radioactive cloud produced by the nuclear weapon that attached the facility, predictions are made for the gamma does from this source of radioactivity. As a comparison study the gamma dose due to the atmospheric nuclear tests from the period of 1951 to 1962 has been computed. The computed and measured values from Grove, UK and Chiba, Japan agree to within a few percent. The global deposition of radioactivity and resultant gamma dose from a hypothetical strategic nuclear exchange between the US and the USSR is reported. Of the assumed 5300 Mton in the exchange, 2031 Mton of radioactive debris is injected in the atmosphere. The highest estimated average whole body total integrated dose over 50 years (assuming no reduction by sheltering or weathering) is 23 rem in the 30 to 50 degree latitude band. If the attack included a 100 GW(e) nuclear power industry as targets in the US, this dose is increased to 84.6 rem. Hotspots due to rainfall could increase these values by factors of 10 to 50.

  4. Dose estimation for atomic bomb survivor studies: its evolution and present status.

    Science.gov (United States)

    Cullings, Harry M; Fujita, Shoichiro; Funamoto, Sachiyo; Grant, Eric J; Kerr, George D; Preston, Dale L

    2006-07-01

    In the decade after the bombings of Hiroshima and Nagasaki, several large cohorts of survivors were organized for studies of radiation health effects. The U.S. Atomic Bomb Casualty Commission (ABCC) and its U.S./Japan successor, the Radiation Effects Research Foundation (RERF), have performed continuous studies since then, with extensive efforts to collect data on survivor locations and shielding and to create systems to estimate individual doses from the bombs' neutrons and gamma rays. Several successive systems have been developed by extramural working groups and collaboratively implemented by ABCC and RERF investigators. We describe the cohorts and the history and evolution of dose estimation from early efforts through the newest system, DS02, emphasizing the technical development and use of DS02. We describe procedures and data developed at RERF to implement successive systems, including revised rosters of survivors, development of methods to calculate doses for some classes of persons not fitting criteria of the basic systems, and methods to correct for bias arising from errors in calculated doses. We summarize calculated doses and illustrate their change and elaboration through the various systems for a hypothetical example case in each city. We conclude with a description of current efforts and plans for further improvements. PMID:16808610

  5. Dose estimation for the reuse of wooden chips contaminated by radioactive cesium

    International Nuclear Information System (INIS)

    Wood and wooden wastes potentially contaminated by radioactive cesium released by Fukushima Daiichi Nuclear Power Plant have been reused for various purposes as wooden chips. The Ministry of the Environment indicated that the general disaster wastes including the wooden wastes were reusable with the criteria of total radioactive cesium (cesium-134 and metal generated at nuclear power plant and not on dose estimation for reuse of wooden chips. The purpose of this study is to confirm the validity of the criteria by the dose estimation approach. We investigated actual conditions of production and use for main five reuse purposes of wooden chips around Fukushima. On the basis of this investigation, exposure pathways and parameters for workers and public involved with the reuse of wooden chips were selected. We calculated dose for the exposure pathways and evaluated radioactive concentrations of wooden chips corresponding to dose criteria for safety reuse of radioactive materials. From the calculation result, all radioactive concentrations corresponding to the dose criteria are more than the reuse criteria of 100 Bq/kg, which ensures the validity of the criteria for the safety of present reuse of wood and wooden wastes. (author)

  6. Amorphous and crystalline optical materials used as instruments for high gamma radiation doses estimations

    Science.gov (United States)

    Ioan, M.-R.

    2016-06-01

    Nuclear radiation induce some changes to the structure of exposed materials. The main effect of ionizing radiation when interacting with optical materials is the occurrence of color centers, which are quantitatively proportional to the up-taken doses. In this paper, a relation between browning effect magnitude and dose values was found. Using this relation, the estimation of a gamma radiation dose can be done. By using two types of laser wavelengths (532 nm and 633 nm), the optical powers transmitted thru glass samples irradiated to different doses between 0 and 59.1 kGy, were measured and the associated optical browning densities were determined. The use of laser light gives the opportunity of using its particularities: monochromaticity, directionality and coherence. Polarized light was also used for enhancing measurements quality. These preliminary results bring the opportunity of using glasses as detectors for the estimation of the dose in a certain point in space and for certain energy, especially in particles accelerators experiments, where the occurred nuclear reactions are involving the presence of high gamma rays fields.

  7. Estimation of delivered doses to the fetus in a external radiation therapy treatment of megavoltage

    International Nuclear Information System (INIS)

    This work, stimulated by the entrance to our radiotherapy service several cases of central nervous system injury in pregnant patients, involves the estimation of doses to the fetus from the comparative analysis and verification of theoretical and experimental data. Um phantom was designed with the pregnant morphology about 28 weeks gestation, with inserts for waterproof ionization chamber in the head and abdominal area. From the scan of the anthropomorphic phantom were reproduced in 3D planner treatments comprised of pregnant patients, estimating the dose in the lesion and at different points in the abdominal area. With the phantom in the beam of radiation treatment conditions were measured with the camera dose at the same points of the abdomen mentioned and the isocenter of the injury. The dose was also measured on surface of the abdominal area with diode array to establish correlation with the measured dose ionization chamber calibrated with water. The work provided medical radiotherapists fundamental experimental data for elevated risk assessment framework for radiation protection of the fetus. It also set the reference calibration for in vivo dosimetry in the abdominal area in pregnant patients treated for external radiotherapy. The results obtained with the implemented dosimetry design will determine the procedures that will form the operating rules institution and thus how professionals working within it

  8. Biochemical estimation of ovaries after whole body irradiation with low doses of gamma radiation

    International Nuclear Information System (INIS)

    Public concern is being expressed over the effects on men and his environment of exposure to low levels of ionizing radiation from the increasing use of atomic energy in medicine industry and power generation. An evaluation of the toxic effects of gamma radiation on female reproduction was made by biochemical estimations of cytoplasmic and membrane bound, Glycogen, Acid and Alkaline phosphatases and cholesterol in the rat varies after whole body irradiation with the low doses of gamma rays. Female Sprague Dawley rats of 12 weeks were divided randomly into four groups Two groups were exposed to 60Co gamma rays of 0.10 Gy and 0.40 Gy respectively at the dose rate 0.0589 Gy/min. These groups were further exposed to the same respective doses and dose rates each month for two consecutive months i .e. when the animals were 16 and 20 weeks old. Total doses delivered in three fractionated doses to the two groups were therefore 0.30 Gy and 1.20 Gy respectively. The remaining two groups were exposed as above but at the dose rate of 0.00368 Gy/min. This would mean that these animals received the same respective doses i.e 0.30 Gy and 1.20 Gy but at the dose rate 1/16th of the above. A day after the last dose the animals were sacrificed by decapitation, ovaries were extirpated put in normal saline and freed from fat and adhering connective tissues. The cleared ovaries were soaked on a piece of filter paper, weighed, minced and homogenized in known volume ice-cold phosphate - buffer saline (PBS, pH 7.4) and the ovarian homogenate was centrifuged for biochemical estimation. Radiation caused degenerative changes in the ovaries as evidenced by a significant decrease in the concentration of cytoplasmic as well as membrane bound glycogen and cholesterol. AKP activity is associated with follicular atrophy. The growing follicles had less AKP activity than antral follicle. The high concentration of ACP in small antral follicles might limit their ability to respond radiation stimulation

  9. Estimation of external dose by car-borne survey in Kerala, India.

    Science.gov (United States)

    Hosoda, Masahiro; Tokonami, Shinji; Omori, Yasutaka; Sahoo, Sarata Kumar; Akiba, Suminori; Sorimachi, Atsuyuki; Ishikawa, Tetsuo; Nair, Raghu Ram; Jayalekshmi, Padmavathy Amma; Sebastian, Paul; Iwaoka, Kazuki; Akata, Naofumi; Kudo, Hiromi

    2015-01-01

    A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7-2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y. PMID:25885680

  10. Estimation of external dose by car-borne survey in Kerala, India.

    Directory of Open Access Journals (Sweden)

    Masahiro Hosoda

    Full Text Available A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7-2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

  11. Estimation of External Dose by Car-Borne Survey in Kerala, India

    Science.gov (United States)

    Hosoda, Masahiro; Tokonami, Shinji; Omori, Yasutaka; Sahoo, Sarata Kumar; Akiba, Suminori; Sorimachi, Atsuyuki; Ishikawa, Tetsuo; Nair, Raghu Ram; Jayalekshmi, Padmavathy Amma; Sebastian, Paul; Iwaoka, Kazuki; Akata, Naofumi; Kudo, Hiromi

    2015-01-01

    A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7–2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y. PMID:25885680

  12. Estimation of dose to man from evironmental tritium based on tritium analysis of hair and urine

    International Nuclear Information System (INIS)

    A dose to man was estimated both from organically bound tritium (OBT) and from free water tritium (FWT). The OBT and FWT were determined from the concentrations of tritium in hair and urine, respectively. It was assumed that the concentration of OBT in the body was equal to that in hair, whereas the concentration of FWT in body water was equal to that in urine. Samples of hair and urine were collected from people taken at random from the general population in the period from May 1982 to October 1983. The OBT concentration in hair was found to be 56+-19 mBq/mL and the FWT concentration in urine was 12+-4 mBq/mL, the ratio of OBT to FWT being 4.7+-2.2. The estimated annual dose to man in the general population was 0.6+-0.2 μGy/a. The contribution of OBT to the total dose was about 68%. It is suggested that the method based on determination of tritium in hair and urine might be useful for dose estimation, especially in regard to critical groups. (author)

  13. Use of prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent

    International Nuclear Information System (INIS)

    The possibility of using measured prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent is explored theoretically. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of a high density polyethylene cylinder to emit prompt gammas from interaction of neutrons with the nuclei of hydrogen and carbon present in polyethylene. The neutron energy dependent responses of hydrogen and carbon nuclei are combined appropriately to match the energy dependent neutron fluence to ambient dose equivalent conversion coefficients. The proposed method is tested initially with simulated spectra and then validated using experimental measurements with an Am–Be neutron source. Experimental measurements and theoretical simulations have established the feasibility of estimating neutron ambient dose equivalent using measured neutron induced prompt gammas emitted from polyethylene with an overestimation of neutron dose at very low energies. - Highlights: • A new method for estimating H⁎(10) using prompt gamma emissions from HDPE. • Linear combination of 2.2 MeV and 4.4 MeV gamma intensities approximates DCC (ICRP). • Feasibility of the method was established theoretically and experimentally. • The response of the present technique is very similar to that of the rem meters

  14. Use of prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Priyada, P.; Sarkar, P.K., E-mail: pradip.sarkar@manipal.edu

    2015-06-11

    The possibility of using measured prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent is explored theoretically. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of a high density polyethylene cylinder to emit prompt gammas from interaction of neutrons with the nuclei of hydrogen and carbon present in polyethylene. The neutron energy dependent responses of hydrogen and carbon nuclei are combined appropriately to match the energy dependent neutron fluence to ambient dose equivalent conversion coefficients. The proposed method is tested initially with simulated spectra and then validated using experimental measurements with an Am–Be neutron source. Experimental measurements and theoretical simulations have established the feasibility of estimating neutron ambient dose equivalent using measured neutron induced prompt gammas emitted from polyethylene with an overestimation of neutron dose at very low energies. - Highlights: • A new method for estimating H{sup ⁎}(10) using prompt gamma emissions from HDPE. • Linear combination of 2.2 MeV and 4.4 MeV gamma intensities approximates DCC (ICRP). • Feasibility of the method was established theoretically and experimentally. • The response of the present technique is very similar to that of the rem meters.

  15. Similarity criterion analysis of dose-response curves in biological assay and radioimmunoassay of hormones

    International Nuclear Information System (INIS)

    The difficulties involved in the control of biological and radioimmunological assay systems, and in the maintenance of standard, as well as, the usual heterogeneity of assayed samples require some evidence of similarity between the dose-response curves obtained with the standard and the sample. Nowadays the parallelism test is used to provide such evidence. However, some indications of non-normal errors distribution, such as the presence of out layers, render the parallelism test both conceptually implausible and statistically inefficient. In such a manner we suggest the non-parametric 'frequencial' test as a more sounding option. (author)

  16. Estimating Radiological Doses to Predators Foraging in a Low-Level Radioactive Waste Management Area

    International Nuclear Information System (INIS)

    Since 1957, Los Alamos National Laboratory has operated Area G as its low-level, solid radioactive waste management and disposal area. Although the waste management area is developed, plants, small mammals, and avian and mammalian predators still occupy the less disturbed and revegetated portions of the land. For almost a decade, we have monitored the concentrations of selected radionuclides in soils, plants, and small mammals at Area G. The radionuclides tritium, plutonium-238, and plutonium-239 are regularly found at levels above regional background in all three media. Based on radionuclide concentrations in mice collected from 1994 to 1999, we calculated doses to higher trophic levels (owl, hawk, kestrel, and coyote) that forage on the waste management area. These predators play important functions in the regional ecosystems and are an important part of local Native American traditional tales that identify the uniqueness of their culture. The estimated doses are compared to Department of Energy's interim limit of 0.1 rad/day for the protection of terrestrial wildlife. We used exposure parameters that were derived from the literature for each receptor, including Environmental Protection Agency's exposure factors handbook. Estimated doses to predators ranged from 9E-06 to 2E-04 rad/day, assuming that they forage entirely on the waste management area. These doses are greater than those calculated for predators foraging exclusively in reference areas, but are still well below the interim dose limit. We believe that these calculated doses represent upper-bound estimates of exposure for local predators because the larger predators forage over areas that are much greater than the 63-acre waste management area. Based on these results, we concluded that predators foraging on this area do not face a hazard from radiological exposure under current site conditions

  17. Estimating internal dose due to ingestion of radionuclides from Nevada Test Site fallout

    International Nuclear Information System (INIS)

    The U.S. Department of Energy initiated the Radiation Exposure Review Project to provide a critical reexamination of radiation doses to people resulting from testing nuclear devices at the Nevada Test Site. One part of this effort focused on the dose resulting from the ingestion of contaminated food. The PATHWAY radionuclide transport model was developed to provide estimates of food concentrations for 20 radionuclides for each of 86 test events and 15 agricultural scenarios. These results were then used as input to the Human Ingestion model to provide dose estimates for individuals and populations in 9 western states. The model considered the life-style and age of the people, and accounted for the transport of milk between locations. Estimates of uncertainty were provided for all doses using Monte Carlo simulation techniques. Propagation of uncertainty between the PATHWAY model and the Human Ingestion model required the development of special strategies to ensure that the inherent correlations between concentrations of the radionuclides in foods were handled properly. In addition, the size of the input data base (60 megabytes), the number of cases to consider (over 30,000), and the number of Monte Carlo simulations (over 6 million) required the development of efficient and reliable methods of data access and storage while running simulations concurrently on up to 14 UNIX workstations. The problems encountered in this effort are likely to be typical of any dose reconstruction involving geographically heterogeneous environmental conditions. This paper documents the methods used to disaggregate the system to achieve computation efficiency, the methods used to propagate uncertainty through the model system, and the techniques used to manage data in a distributed computing environment. The radionuclide and age specific dose factors used in the analysis are also provided

  18. Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight

    Directory of Open Access Journals (Sweden)

    Quinn Brian

    2011-10-01

    Full Text Available Abstract Background The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose. Methods One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population. Results Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters. Conclusions A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques.

  19. Activation of chemical biological defense mechanisms and remission of vital oxidative injury by low dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaoka, K. [Okayama University Medical School, Okayama (Japan); Nomura, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan); Kojima, S. [Science University of Tokyo, Chiba (Japan)

    2000-05-01

    Excessive active oxygen produced in vivo by various causes is toxic. Accumulation of oxidation injuries due to excessive active causes cell and tissue injuries, inducing various pathologic conditions such as aging and carcinogenesis. On the other hand, there are chemical defense mechanisms in the body that eliminate active oxygen or repair damaged molecules, defending against resultant injury. It is interesting reports that appropriate oxidation stress activate the chemical biological defense mechanisms. In this study, to elucidate these phenomena and its mechanism by low dose radiation, we studied on the below subjects. Activation of chemical biological defense mechanisms by low dose radiation: (1) The effects radiation on lipid peroxide (LPO) levels in the organs, membrane fluidity and the superoxide dismutase (SOD) activity were examined in rats and rabbits. Rats were irradiated with low dose X-ray over their entire bodies, and rabbits inhaled vaporized radon spring water, which primarily emitted {alpha}-ray. The following results were obtained. Unlike high dose X-ray, low dose X-ray and radon inhalation both reduced LPO levels and made the state of the SH-group on membrane-bound proteins closer to that of juvenile animals, although the sensitivity to radioactivity varied depending on the age of the animals and among different organs and tissues. The SOD activity was elevated, suggesting that low dose X-ray and radon both activate the host defensive function. Those changes were particularly marked in the organs related to immune functions of the animals which received low dose X-ray, while they were particularly marked in the brain after radon inhalation. It was also found that those changes continued for longer periods after low dose X-irradiation. (2) Since SOD is an enzyme that mediates the dismutation of O{sub 2}- to H{sub 2}O{sub 2}, the question as to whether the resultant H{sub 2}O{sub 2} is further detoxicated into H{sub 2}O and O{sub 2} or not must

  20. Activation of chemical biological defense mechanisms and remission of vital oxidative injury by low dose radiation

    International Nuclear Information System (INIS)

    Excessive active oxygen produced in vivo by various causes is toxic. Accumulation of oxidation injuries due to excessive active causes cell and tissue injuries, inducing various pathologic conditions such as aging and carcinogenesis. On the other hand, there are chemical defense mechanisms in the body that eliminate active oxygen or repair damaged molecules, defending against resultant injury. It is interesting reports that appropriate oxidation stress activate the chemical biological defense mechanisms. In this study, to elucidate these phenomena and its mechanism by low dose radiation, we studied on the below subjects. Activation of chemical biological defense mechanisms by low dose radiation: (1) The effects radiation on lipid peroxide (LPO) levels in the organs, membrane fluidity and the superoxide dismutase (SOD) activity were examined in rats and rabbits. Rats were irradiated with low dose X-ray over their entire bodies, and rabbits inhaled vaporized radon spring water, which primarily emitted α-ray. The following results were obtained. Unlike high dose X-ray, low dose X-ray and radon inhalation both reduced LPO levels and made the state of the SH-group on membrane-bound proteins closer to that of juvenile animals, although the sensitivity to radioactivity varied depending on the age of the animals and among different organs and tissues. The SOD activity was elevated, suggesting that low dose X-ray and radon both activate the host defensive function. Those changes were particularly marked in the organs related to immune functions of the animals which received low dose X-ray, while they were particularly marked in the brain after radon inhalation. It was also found that those changes continued for longer periods after low dose X-irradiation. (2) Since SOD is an enzyme that mediates the dismutation of O2- to H2O2, the question as to whether the resultant H2O2 is further detoxicated into H2O and O2 or not must still be evaluated. Hence, we studied the effect of

  1. A new online detector for estimation of peripheral neutron equivalent dose in organ

    Energy Technology Data Exchange (ETDEWEB)

    Irazola, L., E-mail: leticia@us.es; Sanchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain and Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Lorenzoli, M.; Pola, A. [Departimento di Ingegneria Nuclear, Politecnico di Milano, Milano 20133 (Italy); Bedogni, R. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN), Frascati Roma 00044 (Italy); Terrón, J. A. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Sanchez-Nieto, B. [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago 4880 (Chile); Expósito, M. R. [Departamento de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Lagares, J. I.; Sansaloni, F. [Centro de Investigaciones Energéticas y Medioambientales y Tecnológicas (CIEMAT), Madrid 28040 (Spain)

    2014-11-01

    Purpose: Peripheral dose in radiotherapy treatments represents a potential source of secondary neoplasic processes. As in the last few years, there has been a fast-growing concern on neutron collateral effects, this work focuses on this component. A previous established methodology to estimate peripheral neutron equivalent doses relied on passive (TLD, CR39) neutron detectors exposed in-phantom, in parallel to an active [static random access memory (SRAMnd)] thermal neutron detector exposed ex-phantom. A newly miniaturized, quick, and reliable active thermal neutron detector (TNRD, Thermal Neutron Rate Detector) was validated for both procedures. This first miniaturized active system eliminates the long postprocessing, required for passive detectors, giving thermal neutron fluences in real time. Methods: To validate TNRD for the established methodology, intrinsic characteristics, characterization of 4 facilities [to correlate monitor value (MU) with risk], and a cohort of 200 real patients (for second cancer risk estimates) were evaluated and compared with the well-established SRAMnd device. Finally, TNRD was compared to TLD pairs for 3 generic radiotherapy treatments through 16 strategic points inside an anthropomorphic phantom. Results: The performed tests indicate similar linear dependence with dose for both detectors, TNRD and SRAMnd, while a slightly better reproducibility has been obtained for TNRD (1.7% vs 2.2%). Risk estimates when delivering 1000 MU are in good agreement between both detectors (mean deviation of TNRD measurements with respect to the ones of SRAMnd is 0.07 cases per 1000, with differences always smaller than 0.08 cases per 1000). As far as the in-phantom measurements are concerned, a mean deviation smaller than 1.7% was obtained. Conclusions: The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an

  2. Non-Linear Dose Response Relationships in Biology, Toxicology, and Medicine (June 8-10, 2004). Final Report

    International Nuclear Information System (INIS)

    The conference attracts approximately 500 scientists researching in the area of non-linear low dose effects. These scientists represent a wide range of biological/medical fields and technical disciplines. Observations that biphasic dose responses are frequently reported in each of these areas but that the recognition of similar dose response relationships across disciplines is very rarely appreciated and exploited. By bringing scientist of such diverse backgrounds together who are working on the common area of non-linear dose response relationships this will enhance our understanding of the occurrence, origin, mechanism, significance and practical applications of such dose response relationships

  3. Correlation of clinical outcome to the estimated radiation dose from Boron Neutron Capture Therapy (BNCT)

    Energy Technology Data Exchange (ETDEWEB)

    Chadha, M. [Beth Israel Medical Center, NY (United States). Dept. of Radiation Oncology; Coderre, J.A.; Chanana, A.D. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1996-12-31

    A phase I/II trial delivering a single fraction of BNCT using p-Boronophenylalanine-Fructose and epithermal neutrons at the the Brookhaven Medical Research Reactor was initiated in September 1994. The primary endpiont of the study was to evaluate the feasibility and safety of a given BNCT dose. The clinical outcome of the disease was a secondary endpoint of the study. The objective of this paper is to evaluate the correlation of the clinical outcome of patients to the estimated radiation dose from BNCT.

  4. An estimation of population doses from a nuclear power plant during normal operation

    International Nuclear Information System (INIS)

    A model is presented for estimation of the potential submersion and inhalation radiation doses to people located within a distance of 1000 km from a nuclear power plant during normal operation. The model was used to calculate doses for people living 200-1000 km from hypothetical nuclear power facility sited near the geographical centre of Denmark. Two kinds of sources are considered for this situation: - unit release of 15 isotopes of noble gases and iodines, - effluent releases from two types of 1000 MWe Light Water Power Reactors: PWR and BWR. Parameter variations were made and analyzed in order to obtain a better understanding of the mechanisms of the model. (author)

  5. Estimation of External Dose by Car-Borne Survey in Kerala, India

    OpenAIRE

    Hosoda, Masahiro; Tokonami, Shinji; Omori, Yasutaka; Sahoo, Sarata Kumar; Akiba, Suminori; Sorimachi, Atsuyuki; Ishikawa, Tetsuo; Nair, Raghu Ram; Jayalekshmi, Padmavathy Amma; Sebastian, Paul; Iwaoka, Kazuki; Akata, Naofumi; Kudo, Hiromi

    2015-01-01

    A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was obser...

  6. Correlation of clinical outcome to the estimated radiation dose from Boron Neutron Capture Therapy (BNCT)

    International Nuclear Information System (INIS)

    A phase I/II trial delivering a single fraction of BNCT using p-Boronophenylalanine-Fructose and epithermal neutrons at the the Brookhaven Medical Research Reactor was initiated in September 1994. The primary endpiont of the study was to evaluate the feasibility and safety of a given BNCT dose. The clinical outcome of the disease was a secondary endpoint of the study. The objective of this paper is to evaluate the correlation of the clinical outcome of patients to the estimated radiation dose from BNCT

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

    OpenAIRE

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

    2015-01-01

    The aim of this study was to estimate internal radiation doses and lifetime cancer risk from food ingestion. Radiation doses from food intake were calculated using the Korea National Health and Nutrition Examination Survey and the measured radioactivity of 134Cs, 137Cs, and 131I from the Ministry of Food and Drug Safety in Korea. Total number of measured data was 8,496 (3,643 for agricultural products, 644 for livestock products, 43 for milk products, 3,193 for marine products, and 973 for pr...

  8. Estimated radiation doses from thorium and daughters contained in thoriated welding electrodes

    International Nuclear Information System (INIS)

    The collective radiation dose commitment to the general U.S. population estimated for the annual distribution, use, and disposal of one million thoriated welding electrodes was found to range between 7.9 x 102 to 6.4 x 103 man-rem to the bone (56 to 5.4 x 102 man-rem to the whole body). These values represent the potential dose received by the general U.S. population over a 50-year period following exposure during one year

  9. Equivalent dose (palaeodose) estimation in thermoluminescence dating using a single aliquot of polymineral fine grains.

    Science.gov (United States)

    Michael, C T; Zacharias, N

    2006-01-01

    A single aliquot protocol for the estimation of the natural dose in thermoluminescence dating (SATL) is presented that makes use of polymineral fine grains extracted from ceramic materials. The protocol is demonstrated using aliquots made from two Neolithic sherds and is compared with results from an additive dose polymineral technique. The results of both techniques are in close agreement and highlight the potential advantages of the new procedure, especially when sample availability is restricted, e.g. dating of small pottery fragments, or in cases of authenticity testing. PMID:16822781

  10. Estimation of the average glandular dose on a team of tomosynthesis

    International Nuclear Information System (INIS)

    Seeking to improve the information that gives us an image of mammography the manufacturers have implemented tomosynthesis. With this method of acquisition and reconstruction of image we went from having a 2D to a 3D image image, in such a way that it reduces or eliminates the effect of overlap of tissues. The estimate of the dose, which is always a fundamental parameter in the control of quality of radiology equipment, is more in the case of mammography by the radiosensitivity of this body and the frequency of their use. The objective of this work is the determination of the mean in a team glandular dose of with tomosynthesis mammography. (Author)

  11. The calculation of radial dose from heavy ions: predictions of biological action cross sections

    Science.gov (United States)

    Katz, R.; Cucinotta, F. A.; Zhang, C. X.; Wilson, J. W. (Principal Investigator)

    1996-01-01

    The track structure model of heavy ion cross sections was developed by Katz and co-workers in the 1960s. In this model the action cross section is evaluated by mapping the dose-response of a detector to gamma rays (modeled from biological target theory) onto the radial dose distribution from delta rays about the path of the ion. This is taken to yield the radial distribution of probability for a "hit" (an interaction leading to an observable end-point). Radial integration of the probability yields the cross section. When different response from ions of different Z having the same stopping power is observed this model may be indicated. Since the 1960s there have been several developments in the computation of the radial dose distribution, in the measurement of these distributions, and in new radiobiological data against which to test the model. The earliest model, by Butts and Katz made use of simplified delta ray distribution functions, of simplified electron range-energy relations, and neglected angular distributions. Nevertheless it made possible the calculation of cross sections for the inactivation of enzymes and viruses, and allowed extension to tracks in nuclear emulsions and other detectors and to biological cells. It set the pattern for models of observable effects in the matter through which the ion passed. Here we outline subsequent calculations of radial dose which make use of improved knowledge of the electron emission spectrum, the electron range-energy relation, the angular distribution, and some considerations of molecular excitation, of particular interest both close to the path of the ion and the outer limits of electron penetration. These are applied to the modeling of action cross sections for the inactivation of several strains of E-coli and B. subtilis spores where extensive measurements in the "thin-down" region have been made with heavy ion beams. Such calculations serve to test the radial dose calculations at the outer limit of electron

  12. The study of influence of relevant physical parameters variations on the estimates of the effective doses of Rn-222

    International Nuclear Information System (INIS)

    Based on the analysis of 12 weekly continuous measurements and 4 integral measurements performed in different seasons in actual apartment rooms, bedrooms in particular, we attempted to identify the uncertainties that are involved in the estimation of radiation doses to lung tissues. We found that the parameters of time of residence, concentration, and equilibrium factor can affect substantially the estimate of the overall early effective dose. The weekly averaged concentration measured in one term is not sufficient for a fairly accurate estimate; actually, the equilibrium factor f must also be known and the actual real individual time of residence must be estimated if we want to adopt this approach to the dose estimation

  13. Impacts of Stable Element Intake on 14C and 129I Dose Estimates - Implications for Proposed Yucca Mountain Repository

    International Nuclear Information System (INIS)

    , is 400 pg. This is twice the value listed by the ICRP for Reference Man. This leads to a dose estimate that is too high by a factor of two. Although the ICRP accounts for stable isotope contributions through the selection of a corresponding biological half-time for iodine, the selection in this case may need reevaluation especially with respect to assessments of potential 129I releases from the proposed Yucca Mountain high-level radioactive waste repository. The third conclusion, which confirms earlier studies, is that an increase in the intake of either 14C or 129I will not lead to an increase in the dose if there is a corresponding increase in the intake of stable carbon or iodine such that the ratio of 14C or 129I to stable carbon or iodine does not change

  14. Impacts of Stable Element Intake on C and I Dose Estimates - Implications for Proposed Yucca Mountain Repository

    Energy Technology Data Exchange (ETDEWEB)

    D.W. Moeller; M.T. Ryan; Lin-Shen C. Sun; R.N. Cherry Jr.

    2004-12-21

    stable iodine by the adult U.S. population, for example, is 400 pg. This is twice the value listed by the ICRP for Reference Man. This leads to a dose estimate that is too high by a factor of two. Although the ICRP accounts for stable isotope contributions through the selection of a corresponding biological half-time for iodine, the selection in this case may need reevaluation especially with respect to assessments of potential {sup 129}I releases from the proposed Yucca Mountain high-level radioactive waste repository. The third conclusion, which confirms earlier studies, is that an increase in the intake of either {sup 14}C or {sup 129}I will not lead to an increase in the dose if there is a corresponding increase in the intake of stable carbon or iodine such that the ratio of {sup 14}C or {sup 129}I to stable carbon or iodine does not change.

  15. Biological Stress Response Terminology: Integrating the Concepts of Adaptive Response and Preconditioning Stress Within a Hormetic Dose-Response Framework

    Science.gov (United States)

    Many biological subdisciplines that regularly assess dose-response relationships have identified an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to a moderate to severe level of stres...

  16. Estimation of Rectal Dose Using Daily Megavoltage Cone-Beam Computed Tomography and Deformable Image Registration

    International Nuclear Information System (INIS)

    Purpose: The actual dose delivered to critical organs will differ from the simulated dose because of interfractional organ motion and deformation. Here, we developed a method to estimate the rectal dose in prostate intensity modulated radiation therapy with consideration to interfractional organ motion using daily megavoltage cone-beam computed tomography (MVCBCT). Methods and Materials: Under exemption status from our institutional review board, we retrospectively reviewed 231 series of MVCBCT of 8 patients with prostate cancer. On both planning CT (pCT) and MVCBCT images, the rectal contours were delineated and the CT value within the contours was replaced by the mean CT value within the pelvis, with the addition of 100 Hounsfield units. MVCBCT images were rigidly registered to pCT and then nonrigidly registered using B-Spline deformable image registration (DIR) with Velocity AI software. The concordance between the rectal contours on MVCBCT and pCT was evaluated using the Dice similarity coefficient (DSC). The dose distributions normalized for 1 fraction were also deformed and summed to estimate the actual total dose. Results: The DSC of all treatment fractions of 8 patients was improved from 0.75±0.04 (mean ±SD) to 0.90 ±0.02 by DIR. Six patients showed a decrease of the generalized equivalent uniform dose (gEUD) from total dose compared with treatment plans. Although the rectal volume of each treatment fraction did not show any correlation with the change in gEUD (R2=0.18±0.13), the displacement of the center of gravity of rectal contours in the anterior-posterior (AP) direction showed an intermediate relationship (R2=0.61±0.16). Conclusion: We developed a method for evaluation of rectal dose using DIR and MVCBCT images and showed the necessity of DIR for the evaluation of total dose. Displacement of the rectum in the AP direction showed a greater effect on the change in rectal dose compared with the rectal volume

  17. Potential Offsite Radiological Doses Estimated for the Proposed Divine Strake Experiment, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Ron Warren

    2006-12-01

    An assessment of the potential radiation dose that residents offsite of the Nevada Test Site (NTS) might receive from the proposed Divine Strake experiment was made to determine compliance with Subpart H of Part 61 of Title 40 of the Code of Federal Regulations, National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities. The Divine Strake experiment, proposed by the Defense Threat Reduction Agency, consists of a detonation of 700 tons of heavy ammonium nitrate fuel oil-emulsion above the U16b Tunnel complex in Area 16 of the NTS. Both natural radionuclides suspended, and historic fallout radionuclides resuspended from the detonation, have potential to be transported outside the NTS boundary by wind. They may, therefore, contribute radiological dose to the public. Subpart H states ''Emissions of radionuclides to the ambient air from Department of Energy facilities shall not exceed those amounts that would cause any member of the public to receive in any year an effective dose equivalent of 10 mrem/yr'' (Title 40 of the Code of Federal Regulations [CFR] 61.92) where mrem/yr is millirem per year. Furthermore, application for U.S. Environmental Protection Agency (EPA) approval of construction of a new source or modification of an existing source is required if the effective dose equivalent, caused by all emissions from the new construction or modification, is greater than or equal to 0.1 mrem/yr (40 CFR 61.96). In accordance with Section 61.93, a dose assessment was conducted with the computer model CAP88-PC, Version 3.0. In addition to this model, a dose assessment was also conducted by the National Atmospheric Release Advisory Center (NARAC) at the Lawrence Livermore National Laboratory. This modeling was conducted to obtain dose estimates from a model designed for acute releases and which addresses terrain effects and uses meteorology from multiple locations. Potential radiation dose to a

  18. The estimation of lung dose from mid-perineum ionization chamber measurements in total body irradiations: A quality control check on dose delivery

    International Nuclear Information System (INIS)

    A series of patients (eleven males and eight females) receiving total body irradiation prior to bone marrow transplantation was monitored during treatment by recording the dose from an ionization chamber placed between the thighs in the mid-perineal region. The treatment was delivered by opposed lateral 6 MV photon beams. The patient was encompassed by the radiation field with the maximum collimator opening at a distance of 3.49 m from the X-ray focus to the patient mid-line. An analysis was made of the measured dose and the calculated percentage average lung dose for each patient in the series to seek a correlation between measured doses and patients' anatomical data so that estimates of delivered lung doses could be made. Whilst a global factor can be applied to measured dose to predict lung dose, it is concluded that perineal dose measurements distal to the region where dose is prescribed (mean lung dose) are sub-optimal for checks on target dose delivery. Entrance and exit dose measurements at the level of dose prescription (in the thorax) are preferable for more accurate predictions and quality control checks. 6 refs., 1 tab., 2 figs

  19. The estimation of lung dose from mid-perineum ionization chamber measurements in total body irradiations: A quality control check on dose delivery

    Energy Technology Data Exchange (ETDEWEB)

    Cross, P. [Saint Vincent`s Hospital, Darlinghurst, NSW (Australia)

    1995-11-01

    A series of patients (eleven males and eight females) receiving total body irradiation prior to bone marrow transplantation was monitored during treatment by recording the dose from an ionization chamber placed between the thighs in the mid-perineal region. The treatment was delivered by opposed lateral 6 MV photon beams. The patient was encompassed by the radiation field with the maximum collimator opening at a distance of 3.49 m from the X-ray focus to the patient mid-line. An analysis was made of the measured dose and the calculated percentage average lung dose for each patient in the series to seek a correlation between measured doses and patients` anatomical data so that estimates of delivered lung doses could be made. Whilst a global factor can be applied to measured dose to predict lung dose, it is concluded that perineal dose measurements distal to the region where dose is prescribed (mean lung dose) are sub-optimal for checks on target dose delivery. Entrance and exit dose measurements at the level of dose prescription (in the thorax) are preferable for more accurate predictions and quality control checks. 6 refs., 1 tab., 2 figs.

  20. The Estimation of Collective Dose from Medical Exposures from Diagnostic Nuclear Medicine Examinations in Croatia

    International Nuclear Information System (INIS)

    The largest contribution to the man made radiation exposure of population is from medical exposures and it continues growing. In this work, the collective doses from medical exposures from nuclear medicine diagnostic examinations were estimated for year 2010 in Republic of Croatia according to the European Commission DDM2 project methodology. The collective dose was calculated according to the frequencies of the most frequent nuclear medicine examinations and average effective dose per procedure. The frequencies of different examinations were extracted from Croatian Institute for Health Insurance (CIHI) database. Since the database is made for reimbursement, we investigated usability of the database by comparing it with a survey in 7 out of 9 major Croatian nuclear medicine departments. Average administered activities for 28 most frequent nuclear medicine examinations were surveyed and converted to effective doses according to the ICRP dose coefficients. 41 700 nuclear medicine examinations in a year period leaded to 139 manSv collective effective dose. The frequency of nuclear medicine examination was 10.4 examinations annually per 1,000 members of population with 34.8 μSv effective dose per caput what is comparable to the published values from the DDM2 project. The range and the mean of administered activities are in the range of published values. A lot of uncertainties were revealed if CIHI database is used for population dose survey. If such surveys would be done regularly, the national radiation protection regulatory body and relevant professional societies should work on more straightforward way of data acquisition. (author)

  1. A perspective on dose limits and biological effects of radiation on the foetus

    International Nuclear Information System (INIS)

    The potential biological effects of radiation doses to pregnant workers consistent with Canadian regulations and ICRP recommendations are reviewed. These hazards are in general very small compared to the normal hazards associated with human development. Potential carcinogenic effects may well be the major biological problem associated with foetal exposures. Radiation hazards to the embryo are essentially zero for exposures occurring during the first four weeks after conception. The new ICRP recommendations on exposures of pregnant women suggest a number of problems to be solved. These include (a) improvements in current methods of measuring both external radiation doses and intakes of certain radionuclides in Canada, (b) further research on the metabolism of radionuclides in pregnant women, including concentrations of certain radionuclides in foetal/embryonic tissues and also in adjacent tissues of the mother; and (c) socio-economic problems that may be involved in the implementation of the recommendations on exposures of pregnant workers, particularly in small facilities such as nuclear medicine departments in hospitals. (Author) 3 tabs., 21 refs

  2. Estimation of frequency, population doses and stochastic risks in medical uses of radiopharmaceuticals in Japan, 1982, 3

    International Nuclear Information System (INIS)

    The population doses have been estimated on the basis of the annual number of nuclear medicine procedures evaluated from a nationwide survey, using organ or tissue dose determined with a modified MIRD technique. Risk estimates of the stochastic effects have been evaluated using the organ or tissue doses, population doses and risk factors. The annual population doses from diagnostic nuclear medicine procedures were 4.2 μGy person-1 for the genetically significant dose, 15.7 μGy person-1 for per Caput mean bone marrow dose, 12.0 μGy person-1 for the leukemia significant dose and 5.0 μGy person-1 for the malignant significant dose, respectively. The collective dose equivalents from diagnostic nuclear medicine procedures were estimated to be 2334 man Sv for male and 1907 man Sv for female, with a total of 4241 man Sv. The common use of unsealed radionuclides for therapy is administration of sodium iodine-131 (Na 131I) for hyperthyroidism. The pupulation doses from the therapeutic procedures for hyperthyroidism using 131I were 0.19μGy person-1 year-1 for the genetically significant dose, 8.0μGy person-1 year-1 for the per Caput mena bone marrow dose, 7.0μGy person-1 year-1 for the leukemia significant dose and 464 μGy person-1 year-1 for the malignant significant dose. The collective effective dose equivalent was estimated to be 64000 man Sv for male and 621000 man Sv for female, with a total of 685000 man Sv. The risk of stochastic effects from the uses of radiopharmaceuticals for diagnosis and therapy was estimated to be about 7 for genetic effects, about 5 for leukemogenesis and about 913 for carcinogenesis for the whole population in Japan. The large value of carcinogenetic risk may be due to the highest exposure of the thyroids during the therapy for hyperthyroidism. (author)

  3. Risk estimation of benzene-induced leukemia by radiation equivalent dose

    International Nuclear Information System (INIS)

    Based on the Hiroshima and Nagasaki epidemiological study, risk assessment system for radiation has been well developed and is practically applied to the international protection standards. Hence, defining the radiation equivalent dose for chemical agents could place in the order of their risk. As well as the radiation, benzene causes leukemia to humans. Therefore, we evaluated the radiation-equivalent dose for benzene based on chromosome aberration rates induced by its metabolites and low-dose rate radiation because chromosome aberration is thought to be closely related to the leukemogenesis. Using radiation risk coefficient, the leukemia risk caused by 1 mg/m3 benzene inhalation was estimated 5.5 - 7.3 x 10-8, which is underestimated compared to other studies based on human epidemiological researches. (author)

  4. Dose estimations of fast neutrons from a nuclear reactor by micronuclear yields in onion seedlings

    International Nuclear Information System (INIS)

    Irradiations of onion seedlings with fission neutrons from bare, Pb-moderated, and Fe-moderated 252Cf sources induced micronuclei in the root-tip cells at similar rates. The rate per cGy averaged for the three sources, n>, was 19 times higher than rate induced by 60Co γ-rays. When neutron doses, Dn, were estimated from frequencies of micronuclei induced in onion seedlings after exposure to neutron-γmixed radiation from a 1 W nuclear reactor, using the reciprocal of n> as conversion factor, resulting Dn values agreed within 10% with doses measured with paired ionizing chambers. This excellent agreement was achieved by the high sensitivity of the onion system to fast neutrons relative to γ-rays and the high contribution of fast neutrons to the total dose of mixed radiation in the reactor's field. (author)

  5. Prostate cancer: estimating long-term rectal bleeding risk using dose-volume histograms

    International Nuclear Information System (INIS)

    Objective: Dose-volume histograms (DVHs) may be very useful tools for estimating probability of normal tissue complications (NTCP), but there is not yet an agreed upon method for their analysis. This study introduces a statistical method of aggregating and analyzing primary data from DVHs and associated outcomes, with the goal of exploring the dose-volume relationship for NTCP of the rectum, using long-term data of rectal wall bleeding following irradiation for prostate cancer. Comparison is made between these results and those generated by a mathematical model of NTCP. Materials and Methods: Previously published data were updated on 41 patients with stages T3 and T4 prostatic carcinoma treated with photons followed by perineal proton boost. DVHs of each patient's anterior rectal wall were used as well as data on the occurrence of post-irradiation rectal bleeding (minimum FU > 4 yrs). 128 separate dose-volume combinations were analyzed. For a given dose-volume combination, each patient's DVH was classified as low-risk or high-risk, and this classification was evaluated as an independent variable with treatment outcome as the dependent variable in a logistic regression. The odds-ratios derived from the regression coefficients of those combinations that tested significant (p<.05 by Wald Chi-Square) were compared. Combinations of these 'statistically significant discriminators' (SSDs) were analyzed for predictive power. These results were compared with results of the 'critical volume model', a mathematical model based on underlying biophysical assumptions. Results: 9 of 128 dose-volume combinations proved to be SSDs between bleeders ((15(41))) and non-bleeders ((26(41))), ranging contiguously between 60 Cobalt-Gy-equivalent (CGE) to 70% of the anterior rectal wall and 75 CGE to 30%. Calculated odds-ratios between low- and high-risk groups were not significantly different across the SSDs, a result of high correlation among groupings across SSDs. However, analysis

  6. Predictive estimate of effective dose to family members from patients of thyroid carcinoma treated with radioiodine

    International Nuclear Information System (INIS)

    The radiation dose received by any member of the family attending to the patient released after 131I therapy, primarily will be influenced by the whole body activity retained by the patient, the effective half-life of 131I in the body and the length and proximity of contact with the patient i e. the occupancy factor. According to International Commission of Radiological Protection (ICRP 60), the annual effective dose limit for the members of the public is 1 mSv. In the reports available of the doses received by the family members from patients treated with 131I, the doses either have been estimated using dosimeters worn by the relatives for a specific time period or have been theoretically calculated considering physical decay of the radionuclide. In the present study, the likely doses to the family members were estimated based on calculations, wherein the actual effective half-life of 131I and whole body activity of 131I have been used. Two distances (0.6 m and 1 m) and 4 different occupancy factors (0.125, 0.25, 0.75 and 1), were considered for these calculations. In India, the patient is released from the hospital when the whole body 131I activity is less than or equal to 555 MBq (15 mCi), a limit stipulated by AERB. The objective of retaining the patient in the hospital till the whole body retained activity has fallen below the recommended limit is to minimize the radiation exposure to the general public and family members. Our predictive estimated values of effective dose suggests that with proper instructions of radiation safety and hygiene to the patient, doses to the family members and public can be kept below the limit of 1 mSv. Since some individuals in the family will be knowingly and willingly involved in the care, support and comfort of the patient, a dose of more than 1 mSv is acceptable, however, it should be constrained so that it does not exceed 5 mSv. (author)

  7. Estimation of radiation doses characterizing CANDU spent fuel transport and intermediate dry storage

    International Nuclear Information System (INIS)

    Shielding analyses are an essential component of the nuclear safety. The estimations of radiation doses in order to reduce them under specified limitation values is the main task here. In the last decade, a general trend to raise the discharge fuel burnup has been world wide registered for both operating reactors and future reactor projects. For CANDU type reactors, one of the most attractive solutions seems to be SEU fuels utilization. The goal of this paper is to estimate CANDU spent fuel photon dose rates at the shipping cask/storage basket wall and in air, at different distances from the cask/ basket, for two different fuel projects, after a defined cooling period in the NPP pools. Spent fuel inventories and photon source profiles are obtained by means of ORIGEN-S code. The shielding calculations have been performed by using Monte Carlo MORSE-SGC code. A comparison between the two types of CANDU fuels has been also performed. (authors)

  8. A method applicable to effective dose rate estimates for aircrew dosimetry

    CERN Document Server

    Ferrari, A; Rancati, T

    2001-01-01

    The inclusion of cosmic radiation as occupational exposure under ICRP Publication 60 and the European Union Council Directive 96/29/Euratom has highlighted the need to estimate the exposure of aircrew. According to a report of the Group of Experts established under the terms of Article 31 of the European Treaty, the individual estimates of dose for flights below 15 km may be done using an appropriate computer program. In order to calculate the radiation exposure at aircraft altitudes, calculations have been performed by means of the Monte Carlo transport code FLUKA. On the basis of the calculated results, a simple method is proposed for the individual evaluation of effective dose rate due to the galactic component of cosmic radiation as a function of latitude and altitude. (13 refs).

  9. Estimated dose to man from uranium milling via the terrestrial food-chain pathway

    International Nuclear Information System (INIS)

    One of the major pathways of radiological exposure to man from uranium milling operations is through the terrestrial food chain. Studies by various investigators have shown the extent of uptake and distribution of U-238, U-234, Th-230, Ra-226, Pb-210, and Po-210 in plants and animals. These long-lived natural radioisotopes, all nuclides of the uranium decay series, are found in concentrated amounts in uranium mill tailings. Data from these investigations are used to estimate the dose to man from consumption of beef and milk contaminated by the tailings. This dose estimate from this technologically enhanced source is compared with that from average normal dietary intake of these radionuclides from natural sources

  10. Estimate of whole body doses for Lynette Tew and Becky Farnsworth from Nevada Test Site local fallout

    International Nuclear Information System (INIS)

    Lynette Tew and Becky Farnsworth are decendents whose relatives are litigants in Timothy vs US. The litigants allege that the decendents were harmed by radiation doses received as a result of local fallout from the testing of nuclear weapons at the Nevada Test Site. We have calculated a best estimate of the whole body dose received by each decendent from external exposure and the ingestion of radionuclides with food. In each case the dose via ingestion is trivial compared to the external dose. For Lynette Tew the dose estimate is 0.28 rads. For Becky Farnsworth it is 0.0035 rads. 23 references, 4 tables

  11. Estimation of Collective Effective Dose Due to Cosmic Ray Exposures to Members of The Public and to Airline Passenger

    International Nuclear Information System (INIS)

    Using UNSCEAR 2000 report to United Nation General Assembly and its appendices, Annual collective dose to Egyptian members of the public (75097301). Was estimated to be 252.5 man Sv , hence the average collective effective dose to air line passenger for 10 million is estimated as 25.25 micro Sievert. Furthermore using hypothetical approach for Egyptian passengers who fly locally, regionally and internationally, the collective dose was estimated to be 252.5 man Sv , hence the average average collective effective dose for Egyptian passenger is due to Aviation is 3.36 micro Sievert

  12. Dose estimate for personal music players including earphone sensitivity and characteristic

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Ordoñez Pizarro, Rodrigo Eduardo; Christensen, Anders Tornvig

    2016-01-01

    Personal music players can expose their listeners to high sound pressure levels over prolonged periods of time. The risk associated with prolonged listening is not readily available to the listener, and efforts are made to standardize dose estimates that may be displayed for the user. In the...... present paper, the significance of including the specific sensitivity and frequency response of the earphone type is considered, and a proposal for a revised approach to the implementation of such standardized estimates is assessed. The study is based on simulation of given use-case scenarios using...

  13. Dose estimation of the radiation workers in the SK cyclotron center using dual-TLD method

    International Nuclear Information System (INIS)

    The Cyclotron Center in Shin Kong Wu Ho-Su Memorial Hospital (SK Cyclotron Center) produced the 18F-FDG compound and provided it to the Positron Emission Tomography (PET) center for diagnosis services. The works in SK Cyclotron Center are distinguished into three procedures including production, dispensation, and carry of the compound. As the medical cyclotron was operated to produce the radioactive compounds, secondary radiations such as neutrons and γ-rays were also induced. To estimate the exposure for the staffs working in the SK Cyclotron Center, the dual-TLD (TLD-600/700) chips were used to measure the doses contributed from photons and neutrons during the operation of the cyclotron, and the doses contributed from photons during dispensation and carry of the nuclear compounds. In the results, the mean Hp(10) and Hp(0.07) of the finger for a worker were 2.11 mSv y-1 and 96.19 mSv y-1, respectively. Results estimated by the regular personal chest badges and finger ring dosimeters which considered only the doses of photons were compared. By means of the results of this work, doses contributed from different working procedures and from different types of radiation to the workers in the SK Cyclotron Center were realized.

  14. Estimating doses and risks associated with decontamination and decommissioning activities using the CRRIS

    International Nuclear Information System (INIS)

    The Computerized Radiological Risk Investigation System (CRRIS) is applicable to determining doses and risks from a variety of decontamination and decommissioning activities. For example, concentrations in air from resuspended radionuclides initially deposited on the ground surface and the concentrations of deposited radionuclides in various soil layers can be obtained. The CRRIS will estimate exposure to radon and its progeny in terms of working-level months, and will compute the resulting health risks. The CRRIS consists of seven integrated computer codes that stand alone or are run as a system to calculate environmental transport, doses, and risks. PRIMUS output provides other CRRIS codes the capability to handle radionuclide decay chains. ANEMOS and RETADD-II calculate atmospheric dispersion and deposition for local and regional distances, respectively. Multiple ANEMOS runs for sources within a small area are combined on a master grid by SUMIT. MLSOIL is used to estimate effective ground surface concentrations for dose computations. TERRA calculates food chain transport, and ANDROS calculates individual or population exposures, doses, and risks. Applications of the CRRIS to decontamination problems are discussed. 16 refs., 1 fig

  15. Method for estimating occupational doses to staff in diagnostic X-ray departments

    International Nuclear Information System (INIS)

    Because of the lack of personal monitoring data, a method for estimating the doses received by diagnostic radiological workers, using the normalized work load, is suggested. The primary mathematical mode of the method is as follows: Dsub(i)=pΣsub(j)Σsub(k)rsub(k)Wsub(ijk). Wsub(ijk) is the work load of individual i working at the place under condition k of radiation protection for number of years j; rsub(k) is the correction coefficient for condition; k of radiation protection (normalized coefficient); Dsub(i) is the dose received by a radiological worker; and P is the dose received by the person per normalized work load of 103 person-times. The value of P was determined by means of personal dose monitoring, and it was about 26.3 mGy/103 person-times. In general, the normalized coefficients were affected by the following factors: the condition of radiation protection; effective emission quanta of X-rays per person-time (mA . s) in different kinds of examinations and the quality of X-rays. The normalized coefficients have been estimated. If the work load of a radiological worker is known, the Wsub(ijk) can be worked out by dividing the whole work load into the work loads of different types. Otherwise, the average work load for all diagnostic X-ray workers can be used. (Author)

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Estimation of the Indoor Radon and the Annual Effective Dose from Granite Samples

    International Nuclear Information System (INIS)

    Inhalation of radon and radon daughters increases the risk of lung cancer. The main sources of indoor radon are the building materials especially granite. The aim of this research is to estimate the indoor radon and the annual effective dose from the building materials. Eighteen granite samples bought from the market in Thailand were measured using an ionization chamber (ATMOS 12 DPX) for the radon concentration in air. Radon exhalation rates were calculated using the radon concentration in air. And then the indoor radon and the annual effective dose were estimated from the granite samples using radon exhalation rates. The radon exhalation rates ranged from 0.05-15.55 Bq m-2 h-1 with an average of 5.87 Bq m-2 h-1. The indoor radon concentration ranged from 10.00-59.33 Bq m-3 with an average of 28.53 Bq m-3. The annual effective dose ranged from 0.25-1.49 mSv y-1 with an average of 0.72 mSv y-1. A good correlation between the radon exhalation rate and the indoor radon concentration was observed. Six samples showed the annual effective dose higher than the annual exposure limit for the general public (1 mSv y-1) recommended by the International Commission on Radiological Protection (ICRP).

  18. The combined biological effects of low dose radiation, carbon monoxide, benzene and noise on rats

    International Nuclear Information System (INIS)

    Objective: To investigate the combined biological effects of low dose radiation, carbon monoxide,benzene and noise on rats. Methods: Sixteen male SD rats were randomly divided into experiment group and control group. The experiment group was exposed to carbon monoxide, benzene, low dose radiation and noise daily, the control group was in common environment. Peripheral blood, organ index, and marrow DNA content were detected. Two-dimensional electrophoresis (2-DE) was performed on serum protein analysis. Differential expressed proteins were identified by a matrix assisted laser desorption/ionization time of flight mass spectrometry (MAIDI-TOF-MS). Results: Compared to control group, the liver index, spleen index, thymus index, leukocytes, platelets count, and marrow DNA content of the experiment group were decreased significantly (t=2.732, 4.141, 3.053, 2.211, 2.668, 11.592, P<0.05). 12 altered proteins were detected and through identification, 3 proteins were definite in terms of serum amyloid A-4 protein (SAA4), trichoplein keratin filament-binding protein (TCHP) and tubulin alpha-4A chain (TUBA4A). Conclusions: The hematopoietic system and immune system of rats are damaged significantly with the changes of several serum protein expressions by the combined exposure of low dose radiation, carbon monoxide, benzene and noise. This study may provide new information for the mechanism of the combination effects. (authors)

  19. Thyroid dose estimation with potassium iodide (KI) administration in a nuclear emergency

    International Nuclear Information System (INIS)

    In a breach-of-containment nuclear reactor accident, the near-field exposure is primarily through inhalation of radioiodine. Thyroid blockade by oral potassium iodide (KI) is a practical and effective protective measure for the general public in such an emergency. The retention functions incorporating the thyroid blocking effects by KI have been derived using a standard three-compartment model of iodine metabolism. This allows more accurate estimation of the thyroid dose by calculating the blocking factor. (authors)

  20. Conversion factors for the estimation of effective dose in paediatric cardiac angiography

    International Nuclear Information System (INIS)

    Conversion factors, which relate the kerma-area product to effective dose, have been estimated for paediatric cardiac x-ray angiography. Monte Carlo techniques have been used to calculate the conversion factors for a wide range of projection angles for children of five ages and for adults. Correction factors are provided so that the conversion factors can be adjusted for different tube potentials and filtrations. (author)

  1. A revised burial dose estimation procedure for optical dating of youngand modern-age sediments

    Science.gov (United States)

    Arnold, L.J.; Roberts, R.G.; Galbraith, R.F.; DeLong, S.B.

    2009-01-01

    The presence of genuinely zero-age or near-zero-age grains in modern-age and very young samples poses a problem for many existing burial dose estimation procedures used in optical (optically stimulated luminescence, OSL) dating. This difficulty currently necessitates consideration of relatively simplistic and statistically inferior age models. In this study, we investigate the potential for using modified versions of the statistical age models of Galbraith et??al. [Galbraith, R.F., Roberts, R.G., Laslett, G.M., Yoshida, H., Olley, J.M., 1999. Optical dating of single and multiple grains of quartz from Jinmium rock shelter, northern Australia: Part I, experimental design and statistical models. Archaeometry 41, 339-364.] to provide reliable equivalent dose (De) <